JPH11338298A - Heating device and image forming apparatus provided with the heating device - Google Patents

Abstract

(57) An object of the present invention is to provide a heating device or a heating device capable of preventing overshooting of a heating body until the peripheral speed of the rotating body reaches a predetermined peripheral speed when the rotating body is in a high temperature state. It is an object to provide an image forming apparatus including a heating device. SOLUTION: Power supply from a commercial power supply to a ceramic heater 15 is achieved by setting the peripheral speed of a pressure roller 17 to start when the peripheral speed reaches a predetermined peripheral speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating device for performing a heating process on a recording medium carrying an unfixed image or a fixed image, and an image forming apparatus provided with the heating device.

[0002]

2. Description of the Related Art A recording medium carrying an unfixed image or a fixed image is subjected to a heat treatment by being heated from a heating body while passing through a nip formed between a pair of rotating bodies pressed against each other. Generally, in recent years, a heat-generating portion that generates heat by receiving power supply from a power supply source is provided on one surface of a substrate mainly made of ceramics,
In addition, by adopting a ceramic heater in which a temperature detector is in contact with or close to the other surface of the substrate as a heater,
The startup speed of the heating device is increased.

Conventionally, the temperature control of a ceramic heater (hereinafter, simply referred to as a heater) is performed as shown in FIG.
First, the temperature of the heater is rapidly raised in accordance with the rising temperature raising control, and then the heater is heated to the target heating temperature in accordance with the normal temperature raising control in which the temperature of the heater is gradually raised from the time of the rising temperature raising control. During a period (hereinafter, referred to as a sheet interval) from the end of the processing and the heating process to an arbitrary recording medium to the start of the heating process to the next recording medium, the heater sets the heating target temperature for the heating process and the sheet interval. It was done by being maintained.

That is, when the heating device has not been operated for a long period of time, for example, 5 to 6 hours, the heating device has cooled down to almost room temperature. [° C.].

With the start of the image forming process of the image forming apparatus equipped with such a heating device (time T0), the heater rapidly rises in temperature according to the temperature rise control (time T0 to time T1), and the target heating temperature is 190. Transition temperature taken below [° C] =
The temperature is raised to 180 ° C. (time T0 to time T1).

[0006] With the transition temperature rise of the heater (time T1), the temperature control of the heater is started up, the transition from the temperature rise control to the normal temperature rise control is performed, and the heater is heated until the recording medium enters the nip portion. By raising the temperature to the target temperature, overshoot (a phenomenon in which the heater temperature exceeds the target heating temperature) and undershoot (a phenomenon in which the heater temperature falls below the target heating temperature) are prevented.

Therefore, while the heater is maintained at the target heating temperature during the passage of the recording medium through the nip portion (time T2 to time T3), the unfixed image softens and melts, soaks into the recording medium and becomes a fixed image. It is recorded on a recording medium. Further, the time span from the end of the heating process to an arbitrary recording medium to the start of the heating process to the next recording medium (time T3 to time T3).
At time T4), the heater is maintained at the target sheet interval temperature 170 ° C. lower than the target heating temperature, so that the temperature difference between the sheet passing area and the non-sheet passing area on the surface of the rotating body is alleviated. The heater is maintained at the heating target temperature again until the next nip portion of the recording medium enters.

FIG. 12 shows a conventional heater temperature control.
As shown in FIG. 5, the heating target temperature is set to 190 [° C.], 180 [° C.], 170 [° C.] according to the number of heat-treated recording media.
It is also performed in accordance with the control of the number of sheets to be reduced to 160 [° C.].

That is, the control of the number of sheets means, for example, in the continuous heating process from a state where the heating device is sufficiently cooled as in the morning, for example, the heating during the heating process for the first to third recording media. Target temperature = 190 [° C.] Heating target temperature during the heat treatment of the fourth to sixth sheets = 180 [° C.], 7 to 15
Heating target temperature during heating processing of the recording medium up to the first sheet = 170
[° C.] and the target heating temperature during the heating processing of the sixteenth and subsequent recording media = 160 [° C.]. Control.

The reason is that the temperature of the rotating body increases with an increase in the number of heat-treated recording media, and the amount of heat supplied to the recording medium is determined by “the heating value of the heating member + the heating value of the rotating member = constant”. Since it is preferable that the heat treatment property is maintained, as the temperature of the rotating body increases and the calorific value of the rotating body increases, by reducing the heating target temperature of the heating body and decreasing the calorific value of the heating body, This is because it is necessary to keep the amount of heat supplied to the recording medium constant.

The above-mentioned control is the temperature control of the heater in the continuous heating process. In the intermittent heating process, the first recording medium heating process is performed based on the temperature of the heater before the rotation of the rotating body is started. The temperature control of the heater in the intermittent heating process in which the heating target temperature at the time is determined is disclosed in
It is published in 165368 and the like.

Therefore, conventionally, when the rotating body is started, electric power is supplied to the heater in accordance with the temperature difference between the heater temperature and the heating target temperature before the rotating body is started, so that the heater is heated. The target heating temperature was raised.

[0013]

2. Description of the Related Art Image forming apparatuses employing an electrophotographic method have been widely used all over the world in recent years. Particularly, in an image forming apparatus having a heating apparatus employing a film heating method, Since the temperature of the heater can be instantaneously raised to the target heating temperature, there is an advantage that the power consumption of the heater in the heating standby can be reduced as compared with the heat roller method.

However, in such a heating apparatus, a certain period of time is required until the peripheral speed of the drive motor for rotating the rotating body reaches a predetermined peripheral speed, for example, 200 to 50 hours.
Since a time of about 0 msec is required, a certain amount of time is required until the peripheral speed of the rotating body reaches a predetermined peripheral speed.

Therefore, by starting power supply to the heater simultaneously with the start of rotation of the rotating body as in such a heating device, when power supply to the heater is started when the rotating body is in a high temperature state, Before the peripheral speed of the rotating body reaches the predetermined peripheral speed, the heater instantaneously rises to the heating target temperature, and there is a possibility that "overshoot" occurs in which the heater rises to the target temperature or higher. .

Accordingly, the present invention comprises a heating device or a heating device capable of preventing overshooting of a heating member until the peripheral speed of the rotating member reaches a predetermined peripheral speed when the rotating member is in a high temperature state. An image forming apparatus is provided.

[0017]

SUMMARY OF THE INVENTION According to the present application, the above-described object is to reduce the power while passing a recording medium carrying an unfixed image or a fixed image between a pair of rotatable rotating members which are pressed against each other. A heating device that receives power supply from a supply source and performs a heating process on the recording medium with a heating body that is turned on, and a fixing device including a temperature detection body that detects a temperature of the heating body.
The power supply is achieved by the first invention in which the power supply is set to start when a predetermined time has elapsed from the start of rotation of the rotating body or when the peripheral speed of the rotating body has reached the predetermined peripheral speed.

Further, according to the present application, the above object is achieved in the first invention according to the present application, in which the power supply start timing is determined based on the temperature detected by the temperature detector before rotation of the rotating body. This is also achieved by the second invention.

Further, according to the present application, the above object is achieved in the first invention according to the present application, wherein the power supply start timing is determined based on the elapsed time from the end of a previous series of heating processes. This is also achieved by the third invention.

Further, according to the present application, the above-described object is to provide a recording medium carrying an unfixed image or a fixed image between a pair of rotating members that are pressed against each other and are rotatable, and the power is supplied from a power supply source. In a fixing device provided with a temperature detector for detecting the temperature of the heating body, the fixing device performs a heating process on the recording medium with a heating body that is supplied and turned on.
After being started along with the start of rotation of the rotating body, when a predetermined time has elapsed from the start of rotation or when the peripheral speed of the rotating body has reached a predetermined peripheral speed, it is set to be changed to a predetermined constant power. This is also achieved by the fourth invention.

Further, according to the present application, the above object is achieved according to the fourth invention of the present application, in which the power supplied at the start of rotation of the rotating body is detected by the temperature detector before the rotation of the rotating body starts. This is also achieved by the fifth invention that is determined based on the temperature.

Further, according to the present application, the above-described object is to allow a recording medium carrying an unfixed image or a fixed image to pass between a pair of rotatable rotating members which are pressed against each other and are supplied with a power from a power supply source. In a heating device that performs a heating process on the recording medium with a heating element that is supplied and turned on, and includes a temperature detection element that detects the temperature of the heating element, the heating element starts up when the rotating body starts, and the temperature rises. After the temperature rises sharply in accordance with the control, the heating element is started up and the temperature is gradually increased from the temperature rise control. The transition temperature to the temperature raising control is also achieved by the sixth invention in which the temperature is set to be determined based on the temperature detected by the temperature detector before the start of the rotating body.

Further, according to the present application, the above object is to provide a recording medium carrying an unfixed image or a fixed image while allowing a recording medium carrying an unfixed image or a fixed image to pass between a pair of rotatable rotating members which are pressed against each other, and supplied from a power supply source. In the heating device provided with a temperature detector for detecting the temperature of the heating element, the heating apparatus performs a heating process on the recording medium by a heating element that receives the supply and lights up.
After the temperature rises sharply in accordance with the temperature rise control, the temperature of the heating element is raised to the target heating temperature in accordance with the normal temperature rise control in which the temperature of the heating body is gradually increased from the time of the temperature rise control. The seventh invention in which the transition temperature from the temperature control to the normal temperature increase control is set to be determined based on the elapsed time from the end of the previous series of heating processes is also achieved.

Further, according to the present application, the above object is achieved by allowing a recording medium carrying an unfixed image or a fixed image to pass between a pair of rotatable rotating members which are pressed against each other, and supplied from a power supply source. In a heating apparatus which performs a heating process on the recording medium with a heating body which is supplied and turned on, and which includes a temperature detecting body for detecting the temperature of the heating body, a heating target heating method for heating the heating body is performed as a heating method. The first method of raising the temperature of the heating element to the target heating temperature in accordance with the normal temperature raising control in which the heating element is rapidly raised in temperature according to the temperature control, and then the heating element is started and the temperature is gradually increased from the temperature raising control. In addition, a second method of raising the temperature of the heating body to the target heating temperature only in accordance with the normal temperature rise control alone is predetermined, and the heating body depends on the temperature detected by the temperature detection body before the start of the rotating body. First method and second method By a process selected from also achieved by the eighth invention of being set to heating to target temperature.

Further, according to the present application, the above object is achieved by allowing a recording medium carrying an unfixed image or a fixed image to pass between a pair of rotatable rotating members which are pressed against each other and are supplied with a power from a power supply source. In a heating apparatus which performs a heating process on the recording medium with a heating body which is supplied and turned on, and which includes a temperature detecting body for detecting the temperature of the heating body, a heating target heating method for heating the heating body is performed as a heating method. The first method of raising the temperature of the heating element to the target heating temperature in accordance with the normal temperature raising control in which the heating element is rapidly raised in temperature according to the temperature control, and then the heating element is started and the temperature is gradually increased from the temperature raising control. And, the second method of raising the temperature of the heating body to the heating target temperature in accordance with only the normal temperature rise control is predetermined, and the heating body is
Achieved also by the ninth invention in which the temperature is set to be increased to the heating target temperature by a method selected from the first method and the second method according to the elapsed time from the end of the previous series of heating processes. Is done.

Further, according to the present application, the above-mentioned object is to provide a recording medium carrying an unfixed image or a fixed image between a pair of rotating members which are pressed against each other and are rotatable, and an electric power is supplied from a power supply source. In a heating apparatus which performs a heating process on the recording medium with a heating body which is supplied and turned on, and which includes a temperature detecting body for detecting the temperature of the heating body, a heating target heating method for heating the heating body is performed as a heating method. The first method of raising the temperature of the heating element to the target heating temperature in accordance with the normal temperature raising control in which the heating element is rapidly raised in temperature according to the temperature control, and then the heating element is started and the temperature is gradually increased from the temperature raising control. In addition, a second method of raising the temperature of the heating body to the heating target temperature based only on the normal temperature raising control is predetermined, and the heating body has a reference elapsed time from the end of the previous series of heating processing. When it's over The temperature is raised to the heating target temperature by the first method, and when the elapsed time from the end of the previous series of heating processing is less than the reference elapsed time, the temperature is raised to the heating target temperature by the second method. In addition, the heating target temperature and the supply power at the start of power supply in the second method are the supply power at the end of the previous series of heating processing and the heating target temperature or recording in the previous series of heating processing. The present invention is also achieved by the tenth invention in which the setting is made based on the number of medium heat treatments.

Further, according to the present application, the above object is achieved in the first to tenth inventions according to the present application, wherein one of the rotating bodies is an endless belt-shaped heat-resistant film, and the other is a rotating body. Is a cylindrical or substantially cylindrical pressure roller, and the heating element is provided with a heating element that receives power supply from a power supply source and generates heat on one surface of a substrate mainly made of ceramics. The invention is also attained by an eleventh invention in which a temperature heater is a ceramic heater in which the temperature detector is in contact with or close to the temperature detector.

Further, according to the present application, the object is to form a latent image formed on a latent image carrier into a visible image by using a developer, and then transfer the visible image to a recording medium to obtain an unfixed image. Forming an unfixed image as a fixed image on the recording medium, further comprising a heating device according to the first invention of the present application. It is also achieved by the invention.

Further, according to the present application, the above object is achieved in the twelfth invention according to the present application, in which the power supply start timing is determined based on the temperature detected by the temperature detector before the rotation of the rotating body. This is also achieved by the thirteenth invention.

Further, according to the present application, the above object is achieved in the twelfth invention according to the present application, in that the power supply start timing is determined based on an elapsed time from the end of a previous series of heating processes. This is also achieved by the fourteenth invention.

Further, according to the present application, the object is to form a latent image formed on a latent image carrier into a visible image with a developer, and then transfer the visible image to a recording medium to form an unfixed image. Forming an image on the recording medium, and further recording the unfixed image as a fixed image on the recording medium, the fifteenth aspect including the heating device according to the fourth invention of the present application. It is also achieved by the invention.

Further, according to the present application, the above object is achieved in the fifteenth invention according to the present application, in which the power supplied at the start of rotation of the rotating body is equal to the temperature of the temperature detector before the rotation of the rotating body starts. This is also achieved by the sixteenth invention in which the determination is made based on the detected temperature.

Further, according to the present application, the object is to form a latent image formed and carried on a latent image carrier into a visible image by a developer, and then transfer the visible image to a recording medium to obtain an unfixed image. Is formed on the recording medium, and further, the image forming apparatus records the unfixed image as a fixed image on the recording medium, and includes a heating device according to the sixth invention of the present application. Is also achieved by

Further, according to the present application, the object is to form a latent image formed on a latent image carrier into a visible image by using a developer, and then transfer the visible image to a recording medium to obtain an unfixed image. Forming an unfixed image as a fixed image on the recording medium, and further comprising a heating device according to the seventh invention of the present application. Is also achieved by

Further, according to the present application, the object is to form a latent image formed on a latent image carrier into a visible image with a developer, and then transfer the visible image to a recording medium to obtain an unfixed image. Forming an image on the recording medium, and further recording the unfixed image as a fixed image on the recording medium, the image forming apparatus comprising the heating device according to the eighth aspect of the present invention. Forming equipment.

Further, according to the present application, the object is to form a latent image formed and carried on a latent image carrier into a visible image by a developer, and then transfer the visible image to a recording medium to obtain an unfixed image. Forming an unfixed image on the recording medium as a fixed image, and further comprising a heating device according to the ninth aspect of the present invention. It is also achieved by the invention.

Further, according to the present application, the object is to form a latent image formed on a latent image carrier into a visible image by using a developer, and then transfer the visible image to a recording medium to obtain an unfixed image. Is formed on the recording medium, and further, the image forming apparatus records the unfixed image as a fixed image on the recording medium, and further includes a heating device according to the tenth aspect of the present invention. The invention is also achieved by the invention of

Further, according to the present application, the above object is achieved in the twelfth invention to the twenty-first invention according to the present application, wherein one of the rotating bodies is an endless belt-shaped heat-resistant film, The rotating body is a cylindrical or substantially cylindrical pressing roller, and the heating body is provided with a heating element that generates heat by receiving power supply from a power supply source on one surface of a substrate mainly made of ceramics. The invention is also attained by a twenty-second invention in which the ceramic heater is a ceramic heater in which a temperature detecting body is placed in contact with or close to another surface.

Further, according to the present application, the above object is achieved in the twelfth invention to the twenty-first invention according to the present application, wherein the heating device performs a heating process on a recording medium carrying an unfixed image. The present invention is also achieved by a twenty-third invention in which a fixing device for fixing the unfixed image to the recording medium by performing the fixing is provided.

Further, according to the present application, the above object is achieved in the twelfth invention to the twenty-first invention according to the present application, wherein the heating device performs a heating process on a recording medium carrying an unfixed image. The present invention is also achieved by a twenty-fourth aspect of the invention in which a hypothetical fixing device for hypothetically applying the unfixed image to the recording medium by applying the same is configured.

Further, according to the present application, the above object is achieved in the twelfth invention to the twenty-first invention according to the present application, wherein the heating device performs a heating process on a recording medium carrying an unfixed image. The present invention is also achieved by the twenty-fifth invention in which a surface property modifying apparatus for modifying the surface property of the recording medium by applying the composition is constituted.

That is, according to the first invention of the present application, when a predetermined time has elapsed from the start of rotation of the rotating body or when the circumferential speed of the rotating body has reached the predetermined circumferential speed, the power from the power supply source to the heating body is reduced. Supply is started.

In the second invention according to the present application,
The start timing of power supply from the power supply source to the heating body is determined based on the detected temperature of the temperature detection body before the rotation of the rotating body.

Further, in the third invention according to the present application, the timing of starting power supply from the power supply source to the heating element is determined based on the elapsed time from the end of the previous series of heating processes.

In the fourth invention according to the present application,
After the power supply is started along with the start of rotation of the rotating body, when a predetermined time has elapsed from the start of the rotation or when the peripheral speed of the rotating body has reached the predetermined peripheral speed, the power supply source changes to a predetermined constant power from the power supply source to the heating body. Is changed.

Further, in the fifth invention according to the present application, the power supply at the start of rotation of the rotator is determined based on the temperature detected by the temperature detector before the start of rotation of the rotator.

In the sixth invention according to the present application,
After the heating element rises to the transition temperature in accordance with the startup temperature increase control, the heating element rises to the target heating temperature in accordance with the normal temperature elevation control, and the temperature detected by the temperature detector before the start of the rotating body. , The transition temperature from the startup temperature raising control to the normal temperature raising control is determined.

Further, in the seventh invention according to the present application, after the heating element is heated to the transition temperature in accordance with the startup temperature raising control, the heating element is raised to the target heating temperature in accordance with the normal temperature raising control. The transition temperature from the startup temperature increase control to the normal temperature increase control is determined based on the temperature and the elapsed time from the end of the previous series of heating processes.

In the eighth invention according to the present application,
As a method for raising the heating target temperature of the heating body, the heating body is rapidly heated according to the rising temperature rising control, and then the heating body is gradually warmed up according to the normal temperature rising control. The first method of raising the temperature to the heating target temperature,
And, a second method of raising the temperature of the heating body to the heating target temperature in accordance with only the normal temperature raising control is predetermined.
The heating body is heated to the heating target temperature by a method selected from the first method and the second method according to the detected temperature of the temperature detection body before the start of the rotating body.

Further, in the ninth invention according to the present application, as a method for raising the heating target temperature of the heating element, the heating element is rapidly heated in accordance with the startup temperature increasing control, and then the heating element is activated. The first method in which the heating element is heated to the heating target temperature in accordance with the normal heating control in which the temperature is raised more slowly than in the heating control, and the heating element is heated to the heating target temperature in accordance with only the normal heating control. The second method of letting you do is predetermined, and according to the method selected from the first method and the second method according to the elapsed time from the end of the previous series of heat treatment,
The heating element rises to the target heating temperature.

In the tenth invention according to the present application,
As a method for raising the heating target temperature of the heating body, the heating body is rapidly heated according to the rising temperature rising control, and then the heating body is gradually warmed up according to the normal temperature rising control. The first method of raising the temperature to the heating target temperature,
And, a second method of raising the temperature of the heating body to the heating target temperature in accordance with only the normal temperature raising control is predetermined.
When the elapsed time from the end of the previous series of heating processing is equal to or longer than the reference elapsed time, the heating element is heated to the heating target temperature by the first method, and the elapsed time from the end of the previous series of heating processing is equal to the reference elapsed time. When the time is less than the time, the heating element is heated to the heating target temperature by the second method, and the power supply at the end of the previous series of heating processing, and the heating target temperature or the heating series temperature in the previous series of heating processing. The heating target temperature and the power supply at the start of power supply in the second method are determined based on the number of recording medium heat treatments.

Further, in the eleventh invention according to the present application, the ceramic heater is heated to the heating target temperature by the control described in the first to tenth inventions according to the present application, and
The film and the pressure roller are heated by the ceramic heater maintained at the heating target temperature.

Further, in the twelfth invention according to the present application, when a predetermined time has elapsed from the start of rotation of the rotating body or when the peripheral speed of the rotating body has reached the predetermined peripheral speed, the electric power is supplied from the power source to the heating body. Power supply is started.

Further, in the thirteenth invention according to the present application, the start timing of power supply from the power supply source to the heating element is determined based on the temperature detected by the temperature detection element before the rotation of the rotating body. .

Further, in the fourteenth invention according to the present application, the timing of starting power supply from the power supply source to the heating element is determined based on the elapsed time from the end of the previous series of heating processing.

Further, in the fifteenth invention according to the present application, after the power supply is started at the start of the rotation of the rotating body, a predetermined time has elapsed from the start of the rotation or the peripheral speed of the rotating body has become the predetermined value. When the peripheral speed is reached, the power supply from the power supply source to the heating element is changed to a predetermined constant power.

Further, in the sixteenth invention according to the present application, the power supply at the start of rotation of the rotator is determined based on the temperature detected by the temperature detector before the start of rotation of the rotator.

Further, in the seventeenth invention according to the present application, after the heating element is heated to the transition temperature in accordance with the startup temperature increase control, the heating element is normally heated to the target heating temperature in accordance with the temperature elevation control. Based on the temperature detected by the temperature detector before the rotation of the rotating body starts, the transition temperature from the startup temperature raising control to the normal temperature raising control is determined.

Further, in the eighteenth invention according to the present application, after the heating element is heated to the transition temperature according to the startup temperature increasing control, the heating element is normally heated to the heating target temperature according to the temperature increasing control. The transition temperature from the startup temperature raising control to the normal temperature raising control is determined based on the temperature rise and the elapsed time from the end of the previous series of heating processes.

Further, in the nineteenth invention according to the present application, as a heating target temperature heating method of the heating body, the heating body is rapidly heated in accordance with the startup temperature rising control, and then the heating body is started. The first method in which the heating element is heated to the target heating temperature in accordance with the normal temperature raising control in which the temperature is raised more slowly than in the temperature raising control, and the heating element is raised to the target heating temperature in accordance with only the normal temperature raising control. The second method of warming is predetermined, and according to the method selected from the first method and the second method according to the detected temperature of the temperature detecting body before the start of the rotating body,
The heating element rises to the target heating temperature.

Further, in the twentieth invention according to the present application, as a method of raising the heating target temperature of the heating body, the heating body is rapidly heated in accordance with the rising temperature rise control, and then the heating body is started up. The first method in which the heating element is heated to the target heating temperature in accordance with the normal temperature raising control in which the temperature is raised more slowly than in the temperature raising control, and the heating element is raised to the target heating temperature in accordance with only the normal temperature raising control. The second method of warming is predetermined, and according to the method selected from the first method and the second method according to the elapsed time from the end of the previous series of heat treatment,
The heating element rises to the target heating temperature.

Further, in the twenty-first invention according to the present application, as a heating target temperature heating method of the heating body, the heating body is rapidly heated in accordance with the startup temperature rise control, and then the heating body is heated. The first method of raising the temperature of the heating body to the target heating temperature in accordance with the normal temperature raising control in which the temperature is raised more slowly than in the startup temperature raising control, and the heating element is heated to the target heating temperature in accordance with only the normal temperature raising control. The second method of raising the temperature is predetermined, and when the elapsed time from the end of the previous series of heating processing is equal to or longer than the reference elapsed time, the heating element is heated to the heating target temperature by the first method. When the elapsed time from the end of the previous series of heating processing is less than the reference elapsed time, the heating element is heated to the heating target temperature by the second method, and the supply at the end of the previous series of heating processing is performed. Electricity and heating from previous series of heat treatments Based on the target temperature or the recording medium heating processing sheets, supply power at the start target temperature and the power supply in the second method is determined.

In the twenty-second invention according to the present application, the ceramic heater is heated to the target heating temperature by the control described in the twelfth invention to the twenty-first invention according to the present application. The film and the pressure roller are heated by the ceramic heater maintained at the heating target temperature.

Further, in the twenty-third invention according to the present application, the heating element which can be heated to the target heating temperature by the control described in the twelfth invention to the twenty-first invention according to the present application. The fixing device provided with the fixing device performs a heat treatment on the recording medium carrying the unfixed image, thereby fixing the unfixed image on the recording medium.

Further, in the twenty-fourth invention according to the present application, the heating element which can be heated to the target heating temperature by the control described in the twelfth invention to the twenty-first invention according to the present application. Is applied to the recording medium carrying the unfixed image, thereby causing the unfixed image to be temporarily attached to the recording medium.

Further, in the twenty-fifth invention according to the present application, the heating element which can be heated to the heating target temperature by the control described in the twelfth invention to the twenty-first invention according to the present application. The surface property reforming apparatus having the above-mentioned structure heats the recording medium carrying the fixed image, thereby modifying the surface property of the recording medium.

[0067]

Embodiments of the present invention will be described with reference to the accompanying drawings.

(First Embodiment) First, a first embodiment according to the present invention will be described with reference to FIGS.

FIG. 1 is a schematic cross-sectional view showing a schematic configuration of a laser printer 1 (hereinafter, abbreviated as printer 1) as a preferred example of the image forming apparatus according to the present embodiment.

The printer 1 is an output device (not shown) such as a host computer provided outside the main body of the printer 1.
This is an image forming apparatus in which a reproduced image corresponding to image information provided from a printer is recorded on a recording medium P.

The printer 1 is an image forming apparatus in which an image corresponding to information provided from an output device (not shown) such as a host computer provided outside the main body of the printer 1 is recorded on a recording medium P. .

As shown in FIG. 1, the printer 1 has a drum-shaped latent image carrier 2 which carries an electrostatic latent image corresponding to information provided from an output device on an outer peripheral surface, and develops the electrostatic latent image. And a transfer roller 4 for transferring the developer image as an unfixed image to a recording medium P.
And a fixing device 5 as a heating device for performing a heating process on the recording medium P after the transfer process.

In the present embodiment, the latent image carrier 2 and the developing device 3 are controlled by the engine controller 6 provided in the main body of the printer 1 in this embodiment. I have.

The surface layer of the latent image carrier 2 is a photoconductive layer mainly composed of an organic photoreceptor, and receives a driving force from a driving mechanism (not shown) provided in the main body of the printer 1. Thereby, it is driven to rotate clockwise.

That is, after the outer peripheral surface of the latent image carrier 2 is charged to a predetermined potential distribution by the primary charging roller 7, the laser La blinked from the exposure device 24 according to the information provided from the output device is applied to the mirror 8 or the like. By being exposed through
An electrostatic latent image corresponding to the provided information is formed.

The transfer roller 4 is rotatably supported at a position in contact with or in proximity to the latent image carrier 2 so that the transfer nip portion TN for performing a transfer process on the recording medium P is moved to the latent image carrier. 2 is formed.

That is, in the present embodiment, the transfer roller 4 charges the recording medium P, which has reached the transfer nip portion TN, to a polarity opposite to that of the developer image on the outer peripheral surface of the latent image carrier 2. An electrical interaction is caused between the developer image and the recording medium P, so that the developer image is carried on the recording medium P as an unfixed image.

In this embodiment, the recording medium P
First, a transport roller 11 rotatably supported by a paper feed roller 10 from a cassette 9 removably supported by the main body of the printer 1 at a position upstream of the paper feed roller 10 in the recording medium transport direction. Is fed to

Next, the recording medium P that has reached the transport roller 11 is fed by the transport roller 11 to a sheet feed sensor 12 disposed at a position upstream of the transport roller 11 in the recording medium transport direction.
Transported to

The feed sensor 12 moves the recording medium P to the transfer nip portion TN so that the leading end of the unfixed image carrying portion on the recording medium P and the leading end of the image forming portion on the outer peripheral surface of the latent image carrier 2 are synchronized. Will be transported to

As shown in FIG. 2, the fixing device 5 includes a ceramic heater 15 (hereinafter, simply referred to as a heater 15) as a heating body and an endless belt-shaped film 16 as one rotating body.
And a cylindrical or substantially cylindrical rotatable pressure roller 17 as the other rotating body, and a thermistor temperature sensing element 18 as a temperature detecting body for detecting the temperature of the heater 15 (hereinafter abbreviated as the thermistor 18). , Which supports the heater 15 and guides the movement of the film 16 in a predetermined direction.
And

FIG. 2 is a schematic sectional view showing a schematic configuration of the fixing device 5.

As shown in FIG. 3, the heater 15 is made of a substrate 15 mainly composed of a good heat conductive ceramic such as alumina.
On one surface of A, a heating resistor 15B mainly composed of Ag / Pd (silver palladium) or the like and having a thickness of 10 μm and a width of 1 to 3 mm is provided, and a thermistor 18 is provided on the other surface of the substrate 15A. The one surface is coated with a protective layer 15C mainly composed of glass or fluororesin for protection from sliding contact with the film 16 or the like.

FIG. 3 is a schematic sectional view showing a schematic configuration of the heater 15.

The heating resistor 15B is, as shown in FIG.
A commercial power supply 21 serving as a power supply source via a triac 20
The power supply from the commercial power supply 21 to the heating element 15B is controlled by a central processing unit 23 (hereinafter abbreviated as CPU 23) as a power supply control unit. .

FIG. 4 shows a state in which the heating element 15 is
FIG. 4 is a schematic block diagram illustrating a power supply path to B.

That is, the heater 15 is turned on when the heating element 15B supplied with electric power from the commercial power supply 21 generates heat.

As shown in FIG. 2, the inner peripheral length of the film 16 is slightly smaller than the outer peripheral length of the holder 19, for example, 3 m.
Thus, the film 16 is externally fitted to the holder 19 without tension.

In order to reduce the heat capacity of the film 16, the present embodiment employs a single-layered structure in which the film 16 is an endless band having polyimide as a main component.

The structure of the film 16 is not limited to this embodiment. As another effective structure for reducing the heat capacity, for example, PTFE, PFA, FEP or the like as a heat-resistant material is used as a main component. Single layer structure of endless strip, or polyimide, polyamide imide, PEE
A two-layer structure in which an outer peripheral surface of an endless band mainly composed of K, PES, PPS or the like is coated with an endless band mainly composed of PTFE, PFA, FEP, or the like.

The pressure roller 17 has a cylindrical or substantially cylindrical core metal 17A mainly composed of iron or aluminum or the like covered with an elastic layer 17B mainly composed of a good release silicone rubber or the like. ing.

The pressure roller 17 is configured to be pressed against the film 16 by a pressure mechanism (not shown) provided outside the fixing device 5, so that the pressure rollers 17 are pressed against each other. A nip portion N through which a recording medium P carrying an unfixed image passes is formed between the film 16 and the pressure roller 17.

Further, the pressure roller 17 is driven to rotate counterclockwise by receiving a driving force from a driving mechanism (not shown) provided outside the fixing device 5.

Therefore, while the recording medium P which has begun to enter the nip portion N is conveyed while being held between the film 16 and the pressure roller 17, the unfixed image is melted by the heating of the heater 15, and the recorded image is formed as a fixed image. It will be recorded on the medium P.

Next, control of power supply from the commercial power supply 21 to the heater 15 according to this embodiment will be described with reference to FIG. 5A and 5B are explanatory diagrams of the power supply start timing from the commercial power supply 21 to the heater 15, wherein FIG. 5A is an explanatory diagram of the conventional power supply start timing, and FIG. FIG. 3 is an explanatory diagram of the power supply start timing in the present embodiment.

In this embodiment, it takes about 200 to 500 [msec] from the start of rotation of the pressure roller 17 to the time when the peripheral speed of the pressure roller 17 reaches a predetermined peripheral speed.

As shown in FIG. 5A, in the conventional film heating apparatus, the power supply from the commercial power supply 21 to the heater 15 is started simultaneously with the start of the rotation of the pressure roller 17 (time T0). However, in the present embodiment, as shown in FIG. 5B, at the same time when the peripheral speed of the pressure roller 17 reaches the predetermined peripheral speed (time T1), the commercial power supply 21 The power supply is set to be started. In the present embodiment, the occurrence of overshoot from time T0 to time T1 can be prevented.

Therefore, actually, the maximum sheet passing width = A4 vertical size and the recording medium conveyance speed (process speed) = 51.
When the present embodiment is adopted in the image forming apparatus adopted in [mm / sec], it depends on the performance of a driving motor (not shown) serving as a driving force supply source to the pressing roller 17 and the like.
By starting the power supply from the commercial power supply 21 to the heater 15 at the time T1, the result of preventing the occurrence of overshoot from the time T0 to the time T1 was obtained.

Therefore, in the present embodiment, the power supply from the commercial power supply 21 to the heater 15 is started at the same time when the peripheral speed of the pressure roller 17 reaches the predetermined peripheral speed.
Overshoot from the start of rotation of the pressure roller 17 to the arrival at the predetermined peripheral speed can be reliably prevented.

The overshoot occurs halfway from the start of rotation of the pressure roller 17 to the peripheral speed of the pressure roller 17 reaching a predetermined peripheral speed when the pressure roller 17 is sufficiently warm.

Therefore, when the pressure roller 17 is at a relatively low temperature, even if the power supply from the commercial power supply 21 to the heater 15 is started at the same time when the rotation of the pressure roller 17 is started, the pressure roller 17 No overshoot can occur from the start of rotation of the roller until the peripheral speed of the pressure roller 17 reaches a predetermined peripheral speed.

Therefore, in the present embodiment, the temperature of the heater 15 at any time before the rotation of the pressure roller 17 starts (hereinafter referred to as the initial temperature of the heater 15) is detected by the thermistor 18, The initial temperature of the heater 15 is 70
When the temperature is lower than [° C.], as shown in FIG.
The power supply from the commercial power supply 21 to the heater 15 is started at the same time when the rotation of the pressure roller 17 is started. When the initial temperature of the heater 15 is 70 ° C. or more, as shown in FIG. The power supply may be started at the same time when the pressure roller 17 reaches the predetermined peripheral speed.

Therefore, in this embodiment, the heater 1
When the pressure roller 17 is at a relatively low temperature, the power supply start timing from the commercial power supply 21 to the heater 15 is switched based on the initial temperature of the heater 1.
5 can be instantly heated to the heating target temperature,
Further, when the pressure roller 17 is sufficiently warm, it is possible to reliably prevent the occurrence of overshoot from the start of rotation of the pressure roller 17 to the arrival at the predetermined peripheral speed, and it is preferable that the operability is better than that of the previous embodiment. The advantage is that a simple fixing device can be realized.

Further, in the present embodiment, a timer is provided in the image forming apparatus of the present embodiment, and the heater 1 is supplied from the commercial power source 21 based on the elapsed time from the end of the previous series of heating processing.
5 may be switched.

That is, specifically, when the elapsed time from the end of the previous series of heating processing is 40 seconds or more,
As shown in FIG. 5A, the power supply from the commercial power supply 21 to the heater 15 is started at the same time when the rotation of the pressure roller 17 is started. On the other hand, when the elapsed time is less than 40 [seconds], as shown in FIG. As shown in (B), the power supply may be started at the same time when the pressure roller 17 reaches a predetermined peripheral speed,
It is needless to say that the same effect and advantage as in the present embodiment can be obtained by switching the power supply start timing from the commercial power supply 21 to the heater 15 based on the elapsed time.

(Second Embodiment) Next, a second embodiment according to the present invention will be described with reference to FIGS.
The schematic configuration of the image forming apparatus and the fixing device according to the present embodiment is the same as the schematic configuration of the image forming apparatus and the fixing device of the first embodiment. Omitted.

FIG. 6 is a schematic diagram for explaining switching of the number of input waves to the heater 15 according to the present embodiment.
(A) shows the state of the heater 15 when the heater 15 is fully turned on.
FIG. 4B is a diagram showing the input wave number to the heater 15, while FIG. 6B is a diagram showing the input to the heater 15 of 8 [waves] of the basic wave number = 15 [waves].

In the present embodiment, as shown in FIG. 6A, the temperature control of the heater 15 is performed by setting the half-wave of the AC power output from the commercial power supply 21 to one wave number and the fundamental wave number to 15 waves. Wave number control is adopted.

That is, when the frequency of the AC power supply output from the commercial power supply 21 is 50 [Hz], one wave number = 1
0 [msec], so that the number of fundamental waves = 15 waves = 1
It reaches 50 [msec].

Therefore, in this embodiment, as shown in FIG. 6, by switching the number of input waves actually input to the heating resistor 15B of the heater 15 out of the 15 fundamental waves, 150 [msec. ], The wave number control for controlling the power supply from the commercial power supply 21 to the heating resistor 15B is adopted.

Conventionally, as shown in FIG. 7A, when the heater 15 is cooled down to about room temperature, the "basic" as shown in FIG. Wave number =
15 waves "is input to the heating resistor 15B,
After the heater 15 is heated to a transition temperature of 180 ° C., which is 10 ° C. lower than the target heating temperature = 190 ° C., the transition temperature of the heater 15 is raised by 180 ° C. By shifting from the temperature increase control to the PID control which is the normal temperature increase control, the temperature of the heater 15 is raised to the target heating temperature to prevent overshoot and undershoot.

Thus, the target heating temperature of the heater 15 = 19
After the temperature rises to 0 [° C.], the heating resistor 1 is maintained in order to maintain the heater 15 at the target heating temperature = 190 [° C.].
The input wave number input to 5B is 150 according to the PID control.
It is switched every [msec].

FIGS. 7A and 7B are explanatory diagrams of the startup temperature raising control according to the present embodiment. In particular, FIG. 7A shows the startup input to the heating resistor 15B by the conventional startup temperature raising control. FIG. 8B is a control table of the rising wave number which is input to the heating resistor 15B in the rising temperature rising control of the present embodiment.

In the conventional startup temperature raising control, FIG.
After the heating target temperature and the rising wave number of the heater 15 are determined based on the comparison between the control table of FIG. 5A and the initial temperature of the heater 15, the heater 15 is input by inputting the determined rising wave number to the heating resistor 15B. Was heated to the target heating temperature.

However, in the conventional startup temperature raising control, the thermistor 18 sets the temperature of the heater 15 to 150 [ms].
ec], and the number of rising waves is increased or decreased based on a comparison result of the thermistor detected temperature before 150 [msec] and the thermistor detected temperature at the present time.

That is, for example, when the difference between the thermistor detection temperature before 150 [msec] and the thermistor detection temperature at the present time is 10 [° C.] or less, the number of rising waves is up to 15 one by one. The rise and fall of the rising wave number to the effect of increasing is being performed.

By the way, when the switching of the rising wave number is executed, the case where the temperature of the heater 15 is extremely difficult to rise is increased. In this case, the temperature of the heater 15 is likely to rise.

Therefore, during the switching of the rising wave number, "overshoot from the start of rotation of the pressure roller 17 to the peripheral speed of the pressure roller 17 reaching the predetermined peripheral speed" cannot occur. Thus, hereinafter, the input wave number once determined is switched during the execution of the start-up control over the start-up temperature rise control of the heater 15 according to the present embodiment.

In the present embodiment, as shown in the control table of FIG. 7B, the rising wave number from the start of the rotation of the pressure roller 17 until the peripheral speed of the pressure roller 17 reaches a predetermined peripheral speed is It is set to a value smaller than the rising wave number after the peripheral speed of the pressure roller 17 reaches the predetermined peripheral speed, and the heating resistor 15B is applied to the peripheral speed of the pressure roller 17 when the peripheral speed reaches the predetermined peripheral speed. The input wave number is switched based on the control table of FIG.

That is, in the present embodiment, based on the elapsed time from the start of rotation of the pressure roller 17 and the control table of FIG. The rising wave number in the period until the peripheral speed reaches the predetermined peripheral speed is determined. Next, the rising wave number is switched based on the control table of FIG. In addition, it is possible to prevent occurrence of overshoot from the start of rotation of the pressure roller 17 to the time when the peripheral speed of the pressure roller 17 reaches a predetermined peripheral speed.

Therefore, when the present embodiment is employed in the image forming apparatus having the above-described various numerical values, it depends on the performance of the driving motor serving as the driving force supply source of the pressing roller 17 and the like. ), The temperature of the heater 15 is raised in accordance with the startup temperature raising control based on the control table, thereby causing the occurrence of overshoot from the start of rotation of the pressure roller 17 until the peripheral speed of the pressure roller 17 reaches a predetermined peripheral speed. Was obtained.

The overshoot occurs between the start of rotation of the pressure roller 17 and the arrival of the peripheral speed of the pressure roller 17 at a predetermined peripheral speed when the pressure roller 17 is sufficiently warm. When the temperature of the roller 17 is relatively low, it is determined that the temperature of the heater 15 has been increased by inputting the rising wave number shown in the control table of FIG. It is not considered possible.

Therefore, as shown in the control table of FIG.
When the initial temperature of the heater 15 is lower than 70 [° C.], the rising wave number is maintained at a value determined with the start of the rotation of the pressure roller 17, while the initial temperature of the heater 15 is 7 °.
When the temperature is equal to or higher than 0 ° C., it is needless to say that the above effect can be obtained by setting the rising wave number to be switched when the peripheral speed of the pressure roller 17 reaches a predetermined peripheral speed. .

That is, the initial temperature of the heater 15 = 60 [° C.]
Is satisfied, the temperature of the heater 15 is raised to the transition temperature while maintaining the rising wave number = 13 [waves] during the rising temperature rising control of the heater 15, while the initial temperature of the heater 15 is 80 [ ° C].
7 is set to 7 [waves] from the start of rotation of the pressure roller 7 to the peripheral speed of the pressure roller 17 reaching the predetermined peripheral speed. The rising wave number is switched to 12 [waves].

Accordingly, in the image forming apparatus employing the control table shown in FIG. 8, the above-described effect can be obtained, and the initial temperature of the heater 15 is set to the threshold temperature = 70 [° C.].
When the pressure roller 17 is less than the predetermined temperature, the rising wave number input to the heating resistor 15B is set to a large value from the beginning of the rotation of the pressure roller 17 in accordance with the rising temperature rising control, so that the pressure roller 17 is kept at a relatively low temperature. Since overshooting from the start of rotation of the pressure roller 17 to the arrival of the peripheral speed of the pressure roller 17 at a predetermined peripheral speed cannot occur, the heater 1
5 has the advantage that the temperature can be quickly raised to the target heating temperature, and also has the advantage that the fixability of the unfixed image carried on the recording medium P can be ensured. .

(Third Embodiment) Next, a third embodiment according to the present invention will be described with reference to FIGS. The schematic configuration of the image forming apparatus and the fixing device according to the present embodiment is the same as the schematic configuration of the image forming apparatus and the fixing device of the first embodiment. Omitted.

In the present embodiment, when the pressure roller 17 is sufficiently warm, the difference X between the transition temperature and the target heating temperature at which the transition from the rising temperature raising control to the PID control which is the normal temperature raising control is performed. Is set to be switched based on the temperature detected by the thermistor 18, thereby preventing the occurrence of overshoot from the start of rotation of the pressure roller 17 until the peripheral speed of the pressure roller 17 reaches a predetermined peripheral speed. .

FIG. 9 is a diagram for explaining the switching of the difference between the target heating temperature and the transition temperature according to the present embodiment. In particular, FIG. 9A is a control table showing a conventional set value of the transition temperature. Yes, on the other hand, (B) is a control table showing set values of the transition temperature in the present embodiment.

In the related art, as shown in FIG. 9A, the difference X = the target heating temperature−the transition temperature = the constant, and is based on the initial temperature of the heater 15 detected by the thermistor 18 and the like. After the heating target temperature of the heater 15 is determined, from the start of rotation of the pressure roller 17 to the transition temperature = the heating target temperature−10 [° C.] until the temperature of the heater 15 rises, the heater 15 is controlled according to the rising temperature rising control. After the temperature of the heater 15 was raised to the transition temperature, the temperature was raised from the rising temperature control to the normal temperature raising control in accordance with the transition temperature of the heater 15, and the heater 15 was heated to the heating target temperature.

The PID control is a well-known proportional / integral / differential control, and is a control for determining an input wave number input to the heating resistor 15B so as to maintain the heater 15 at a heating target temperature. .

In the PID control name, "P" stands for proportional control, "I" stands for integral control, and "D" stands for differential control. In the following, proportional control and the like will be abbreviated as P control and the like.

That is, the heating resistor 15 in the PID control
The input wave number to B is generally determined at the start of PID control and based on a base setting wave number (hereinafter, referred to as an offset wave number) determined based on the ID control and P control. In the present embodiment, each control of the D control is executed once every 150 [msec], and each parameter is changed in each control.

Thus, the PID control according to the present embodiment will be described in detail below.

In the P control, based on the offset wave number, the fundamental wave number = 15 waves from the difference between the current temperature of the heater 15 detected by the thermistor 18 and the target heating temperature of the heater 15 (see FIG. 6). Of the input wave number actually input to the heating resistor 15B, a predetermined control table, for example, in the present embodiment, a P control table shown in FIG. I have.

FIG. 10 is a control table for P control according to this embodiment.

In the I control, the temperature of the heater 15 is prevented from gradually increasing with the temperature of the pressure roller 17, and the optimal offset wave number is determined. The offset wave number is changed based on the cumulative addition value of the difference between the temperature of the heater 15 and the target heating temperature at the start of the PID control detected by the above, and a predetermined control table (not shown). Has become.

Further, in the D control, the input power to the heating resistor 15B changes due to a voltage fluctuation or the like based on external disturbance or the like, and a rapid change in the temperature of the heater 15 occurs. In this case, the offset wave number is changed so as to quickly return the heater 15 to the target heating temperature.

That is, in the PID control of the present embodiment, the comparison result between the thermistor detected temperature before 150 [msec] and the current thermistor detected temperature is based on a predetermined control table (not shown). , The number of offset waves is changed.

The initial offset wave number at the start of the PID control is determined during the fixing process on the first recording medium P by the heating resistor 15B at the end of the temperature rise control.
According to the present embodiment, for example, 4
This is done by subtracting waves.

Next, during the fixing process to the second recording medium, the offset wave number at the end of the previous PID control and the heating target temperature in the previous PID control are provided in the printer body or the like. Stored in the storage means (not shown), and the stored value of the storage means is adopted as a new initial offset wave number.

The startup temperature rise control is a control for rapidly raising the temperature of the heater 15 to the transition temperature.
The control is a control for raising the temperature from the transition temperature of the heater 15 to the target heating temperature and for maintaining the target heating temperature of the heater 15. By shifting from the temperature control to the PID control, the occurrence of overshoot and undershoot at the time of raising the heating target temperature of the heater 15 has been attempted.

By speeding up the transition from the rising temperature rise control to the PID control, it is possible to prevent a large temperature rise of the heater 15 and to prevent a temperature effect, that is, to maintain the target heating temperature of the heater 15. , The temperature change of the heater 15 can be reduced.

Therefore, conventionally, the heater 15 starts up at the same time as the rotation of the pressure roller 17 and starts to rapidly rise to the transition temperature in accordance with the temperature rise control. The control was shifted from the startup temperature increase control to the PID control, and the heater 15 was heated from the transition temperature to the target heating temperature, and the difference X = the target heating temperature−the transition temperature = 10 [° C.] = Constantly maintained.

However, in this embodiment, the heater 1
By switching the difference X (= heating target temperature−transition temperature) based on the initial temperature of No. 5, when the pressure roller 17 is sufficiently warm, the rotation of the pressure roller 17 It is possible to prevent the occurrence of overshoot until the peripheral speed reaches the predetermined peripheral speed.

Therefore, when the present embodiment is actually applied to an image forming apparatus having the above-mentioned various values,
As a result, overshoot was prevented from occurring from the start of rotation of the pressure roller 17 to the time when the peripheral speed of the pressure roller 17 reached a predetermined peripheral speed.

In this embodiment, as shown in FIG. 9B, when the initial temperature of the heater 15 is less than 70 ° C., the difference X = the target heating temperature−the transition temperature = 10
[° C.], while the initial temperature of the heater 15 is 70
If it is equal to or higher than [° C.], the difference X is set to be 40 [° C.].

Therefore, in this embodiment, when the pressure roller 17 is sufficiently warmed, that is, when the initial temperature of the heater 15 is 70 ° C. or more, the difference X = the target heating temperature. -Transfer temperature = 40 [° C], heater 15
When the initial temperature of the pressure roller 17 is less than 70 ° C., the difference X is set to a value larger than 10 ° C. so that the peripheral speed of the pressure roller 17 reaches a predetermined peripheral speed from the start of rotation of the pressure roller 17. The occurrence of overshoot up to this point can be prevented.

In this embodiment, the pressure roller 1
7 is at a relatively low temperature, that is, when the initial temperature of the heater 15 is lower than 70 [° C.], as in FIG. 9A, the difference X = the target heating temperature−the transition temperature = 10 [ ° C]
Since no overshoot can occur between the start of rotation of the pressure roller 17 and the peripheral speed of the pressure roller 17 reaching the predetermined peripheral speed, the temperature of the heater 15 can be quickly raised to the target heating temperature. The advantage of realization is obtained.

Note that, based on the initial temperature of the heater 15 detected by the thermistor 18, the transition temperature from the rising temperature raising control to the normal temperature raising control is determined. However, in the image forming apparatus of this embodiment, Needless to say, a timer may be provided to switch the difference X = the target heating temperature−the transition temperature based on the elapsed time from the end of the previous series of heating processes.

Specifically, when the elapsed time from the end of the previous series of heat treatment is less than 40 [seconds],
Since the pressure roller 17 is sufficiently warm, the difference X = 4
If the elapsed time from the previous series of heat treatment lapses is 40 seconds or more, the pressure roller 17 is at a relatively low temperature, and the difference X = 10 ° C.
It is needless to say that the same effect as in the present embodiment can be obtained by setting to [° C.].

(Fourth Embodiment) Next, a fourth embodiment according to the present invention will be described with reference to FIG.

In the present embodiment, when the pressure roller 17 is sufficiently warmed, the heater 1 is turned on at the same time as the rotation of the pressure roller 17 according to PID control, which is a normal temperature rise control.
By raising the temperature of the pressure roller 5 to the target heating temperature, overshoot is prevented until the peripheral speed of the pressure roller 17 reaches a predetermined peripheral speed.

By the way, conventionally, as shown in FIG. 9 (A), when the temperature of the heater 15 is raised from the target heating temperature to a transition temperature having a difference X = 10 [° C.] lower, the rising temperature raising control is performed. From the transition to the PID control, the heater 15 is heated from the transition temperature to the target heating temperature, that is, the difference X is uniformly set to 10 [° C.] regardless of the initial temperature of the heater 15.

However, in this embodiment, FIG.
When the pressure roller 17 is at a relatively low temperature as shown in FIG.
After the temperature of the heater 5 is raised to the transition temperature, the heater 15 is raised to the transition temperature, the control is switched from the temperature rise control to the PID control, and the heater 15 is heated from the transition temperature to the heating target temperature. ing.

FIG. 11 shows a heater 1 according to this embodiment.
5A and 5B are explanatory diagrams relating to the control up to the heating target temperature increase of 5, and in particular, FIG. 5A is a control table until the heating target temperature of the heater 15 according to the present embodiment is increased, and FIG.
Is a control table up to the heating target temperature increase of the heater 15 when the initial temperature of the heater 15 is 70 [° C.] or more.

On the other hand, when the pressure roller 17 is sufficiently warm, as shown in FIG.
7, the PID control is started with the start of rotation, and the heater 15 is heated to the heating target temperature in accordance with the PID control.

That is, in this embodiment, the heater 15
When the initial temperature of the pressure roller is 60 [° C.], the pressure roller 1
7 and the heater 15 is heated up to a transition temperature 170 [° C.], and then the transition temperature is raised from the start-up temperature rise control to the PID control. Then, the temperature of the heater 15 is raised from the transition temperature to the target heating temperature of 180 ° C.

Further, when the initial temperature of the heater 15 is 80 [° C.], the PI
The D control is started, and the heater 15 is heated to the heating target temperature.

Therefore, when the present embodiment is actually applied to an image forming apparatus having the above-described various values,
Depending on the performance of the driving motor as a driving force supply source of the pressure roller 17, the temperature rise up to the heating target temperature of the heater 15 is performed based on the control tables in FIGS. 11A and 11B. As a result, the result of preventing the occurrence of overshoot from the start of rotation of the pressure roller 17 to the peripheral speed of the pressure roller 17 reaching a predetermined peripheral speed was obtained.

In the present embodiment, when the heater 15 is heated to the heating target temperature only by the PID control, the temperature rising gradient of the heater 15 can be suppressed small.
Thus, it is considered that the time required for heating the heater 15 to the target heating temperature of the heater 15 is longer than in the case where the heater 15 is heated to the target heating temperature in accordance with the startup temperature raising control and the normal temperature raising control.

However, in the present embodiment, when the heating target temperature of the heater 15 is raised only by the PID control, the initial temperature of the heater 15 is 70 ° C. or more, that is, the pressure roller 17 Is sufficiently warm, the pressing roller 17 starts rotating from the pressing roller 17.
Overshoot until the peripheral speed reaches a predetermined peripheral speed can be prevented.

By the way, up to the above embodiment, “PI
In the D control, the initial offset wave number is determined based on the input wave number input to the heating resistor 15B at the end of the temperature rise control during the fixing process on the first recording medium P, for example, by four. It is done by waving. "

However, in the present embodiment, when the pressure roller 17 is sufficiently warm,
Since the heater 15 is heated to the heating target temperature only according to the PID control with the start of the rotation of, and the startup temperature rise control is not performed, it is necessary to arbitrarily set the initial offset wave number.

Therefore, the initial temperature of the heater 15 is set to 70 ° C.
In the case described above, for example, the offset wave number and the number of heat-processed sheets of the recording medium P at the end of the previous PID control are stored in a storage unit (not shown), and the next value is stored based on the stored value in the storage unit. The heating target temperature in the heat treatment is determined, and the initial offset wave number in the next heat treatment =
Offset wave number at the end of previous PID control-Z
By taking Z [wave] to an arbitrary value based on [wave],
It is possible to set an initial offset in the next heat treatment.

Therefore, actually, the target heating temperature in the next heating process = the target heating temperature in the previous heating process-1.
By taking at 0 [° C] and taking Z = 4 [waves]
As a result, overshoot was prevented from occurring from the start of rotation of the pressure roller 17 to the time when the peripheral speed of the pressure roller 17 reached a predetermined peripheral speed.

In this embodiment, the thermistor 1
8 based on the initial temperature of the heater 15 detected by
"Heater 15 based on startup temperature rise control and PID control
Of the heater 15 to the heating target temperature based only on the PID control. However, the image forming apparatus of the present embodiment has a timer. Are provided, based on the elapsed time from the end of the previous series of heating processes, "heat-up to the heating target temperature of the heater 15 in accordance with the startup temperature increase control and PID control" and "the heater 15 in accordance with only the PID control. It is needless to say that the selection may be made to any one of "the heating to the heating target temperature".

Specifically, when the elapsed time from the end of the previous series of heat treatments is less than 40 [seconds],
Since the pressure roller 17 has sufficiently warmed up, the PID control is started with the rotation of the pressure roller 17 and the heater 15 is started.
Is raised to the target heating temperature. On the other hand, if the elapsed time from the end of the previous series of heating processing is 40 seconds or more, the pressure roller 17 is at a relatively low temperature. After the heater 15 is heated up to the transition temperature in accordance with the start-up temperature increase control at the start of rotation of the heater 17, the transition from the start-up temperature increase control to the PID control is performed with the transition temperature increase of the heater 15, and the heater 15 is turned on. It is needless to say that the same effect as in the present embodiment can be obtained by setting the temperature to rise from the transition temperature to the heating target temperature.

Although the first to fourth embodiments have been described as being independent from each other, the first to fourth embodiments can be arbitrarily combined. It goes without saying that you can do it.

Further, in the first to fourth embodiments, the detection of the elapsed time from the end of the previous heating process is performed by detecting the extinction time of the heater 15. For example, various sensors (not shown) provided in the image forming apparatus for detecting the passage of the recording medium, such as detecting the elapsed time after the passage of the recording medium by a paper ejection sensor (not shown) of the heating device. ) Determines the elapsed time from the end of the previous heating process, or detects the stop time of the drive motor for driving the pressure roller to determine the elapsed time from the end of the previous heating process. It goes without saying that the form can be considered.

Furthermore, various numerical values and control values used in the first to fourth embodiments are for convenience of explanation, and any values are used as long as they fall within the scope of the present invention. It goes without saying that it can be taken.

[0171]

As described above, according to the first aspect of the present invention, when a predetermined time has elapsed from the start of rotation of the rotating body or when the peripheral speed of the rotating body has reached the predetermined peripheral speed, Since the power supply from the power supply source to the heating body is started, even when the rotating body is in a high temperature state, overshooting of the heating body until the peripheral speed of the rotating body reaches a predetermined peripheral speed is prevented. be able to.

Further, according to the second aspect of the present invention, based on the temperature detected by the temperature detector before the rotation of the rotating body,
Since the power supply start timing from the power supply source to the heating element is determined, when the rotating body is in a high temperature state, overshoot of the heating body until the peripheral speed of the rotating body reaches a predetermined peripheral speed is determined. When the rotating body is in a relatively low temperature state, the temperature of the nip formed between the rotating body pair can be rapidly increased.

Further, according to the third invention of the present application,
Based on the elapsed time from the end of the previous series of heating processing, the power supply start timing from the power supply source to the heating body is determined, so when the rotating body is in a high temperature state,
It is possible to prevent the heating element from overshooting until the peripheral speed of the rotating body reaches a predetermined peripheral speed, and when the rotating body is in a relatively low temperature state, it is formed between the rotating body pair. Nip portion can be quickly heated.

Further, according to the fourth invention of the present application, after the power supply is started at the start of rotation of the rotating body, a predetermined time has elapsed from the start of rotation or the peripheral speed of the rotating body has been reduced to the predetermined speed. When the speed is reached, the power supply from the power supply source to the heating body is changed to a predetermined constant power, so that even when the rotating body is in a high temperature state, the circumferential speed of the rotating body is set to the predetermined circumferential speed. It is possible to prevent the overshoot of the heating element until reaching the temperature.

Further, according to the fifth invention of the present application,
Since the power supply at the start of rotation of the rotating body is determined based on the temperature detected by the temperature detecting body before the rotation of the rotating body, the temperature of the nip formed between the rotating body pair rises to the target heating temperature. The speed-up of the temperature can be realized according to the detected temperature of the temperature detector before the rotation of the rotating body starts.

Further, according to the sixth invention of the present application, after the heating element is heated to the transition temperature according to the startup temperature raising control, the heating element is raised to the target heating temperature according to the normal temperature raising control. In addition, since the transition temperature from the rising temperature rising control to the normal temperature rising control is determined based on the temperature detected by the temperature detector before the start of the rotating body, when the rotating body is in a high temperature state, Even so, it is possible to prevent overshooting of the heating element until the peripheral velocity of the rotating body reaches the predetermined peripheral velocity.

Furthermore, according to the seventh invention of the present application,
After the heating element rises to the transition temperature in accordance with the startup temperature elevation control, the heating element rises to the target heating temperature in accordance with the normal temperature elevation control, and based on the elapsed time from the end of the previous series of heating processing. Since the transition temperature from the rising temperature raising control to the normal temperature raising control is determined, even when the rotating body is in a high temperature state, the heating body is kept rotating until the circumferential speed of the rotating body reaches a predetermined circumferential speed. Overshoot can be prevented.

Further, according to the eighth aspect of the present invention, as a method for raising the heating target temperature of the heating element, the heating element is rapidly heated in accordance with the startup temperature increasing control, and then the heating element is activated. The first method in which the heating element is heated to the heating target temperature in accordance with the normal heating control in which the temperature is raised more slowly than in the heating control, and the heating element is heated to the heating target temperature in accordance with only the normal heating control. The second method of squeezing is predetermined, and the heating target is set to the heating target according to the method selected from the first method and the second method according to the detected temperature of the temperature detector before the start of the rotating body. Since the temperature rises to a temperature, even when the rotating body is in a high temperature state, overshooting of the heating body until the circumferential speed of the rotating body reaches a predetermined circumferential speed can be prevented.

Further, according to the ninth invention of the present application,
As a method for raising the heating target temperature of the heating body, the heating body is rapidly heated according to the rising temperature rising control, and then the heating body is gradually warmed up according to the normal temperature rising control. The first method of raising the temperature to the heating target temperature,
And, a second method of raising the temperature of the heating body to the target heating temperature in accordance with only the normal temperature raising control is predetermined, and the first method and the second method are performed according to the elapsed time from the end of the previous series of heating processing. The heating element is heated to the heating target temperature by the method selected from the two methods. Therefore, even when the rotating body is in a high temperature state, the heating element is kept until the peripheral speed of the rotating body reaches the predetermined peripheral speed. Overshoot can be prevented.

Further, according to the tenth aspect of the present invention, as a method of raising the heating target temperature of the heating element, the heating element is rapidly heated in accordance with the startup temperature increase control, and then the heating element is activated. The first method in which the heating element is heated to the heating target temperature in accordance with the normal heating control in which the temperature is raised more slowly than in the heating control, and the heating element is heated to the heating target temperature in accordance with only the normal heating control. The second method of squeezing is predetermined, and when the elapsed time from the end of the previous series of heating processing is equal to or longer than the reference elapsed time, the heating element is heated to the heating target temperature by the first method, and When the elapsed time from the end of the series of heating processes is less than the reference elapsed time, the heating element is heated to the heating target temperature by the second method, and the power supply at the end of the previous series of heating processes and , Heating target temperature in the previous series of heat treatment Alternatively, the heating target temperature and the power supply at the start of power supply in the second method are determined based on the number of recording medium heat treatments, so that even when the rotating body is in a high temperature state, It is possible to prevent the heating element from overshooting until the peripheral speed reaches the predetermined peripheral speed.

Further, according to the eleventh aspect of the present invention, the ceramic heater is heated to the heating target temperature by the control described in the first to tenth aspects of the present invention, and
Since the film and the pressure roller are heated by the ceramic heater maintained at the heating target temperature, the heating device having the effects of the first to tenth inventions according to the present application is provided. It is possible to provide a heating device in which a nip portion formed between pressure rollers is quickly heated.

According to the twelfth invention of the present application,
When a predetermined time has elapsed from the start of rotation of the rotating body or when the peripheral speed of the rotating body has reached the predetermined peripheral speed, power supply from the power supply source to the heating body is started. Also, it is possible to provide an image forming apparatus including a heating device that prevents overshooting of the heating body until the peripheral speed of the rotating body reaches a predetermined peripheral speed.

Further, according to the thirteenth aspect of the present invention, the timing of starting the power supply from the power supply source to the heating element is determined based on the temperature detected by the temperature detecting element before the rotation of the rotating body. Therefore, when the rotating body is in a high temperature state, it is possible to prevent overshooting of the heating body until the circumferential speed of the rotating body reaches a predetermined circumferential speed,
Further, when the rotating body is in a relatively low temperature state, it is possible to provide an image forming apparatus provided with a heating device capable of realizing a rapid temperature rise of the nip formed between the rotating body pair.

According to the fourteenth aspect of the present invention,
Based on the elapsed time from the end of the previous series of heating processing, the power supply start timing from the power supply source to the heating body is determined, so when the rotating body is in a high temperature state,
It is possible to prevent the heating element from overshooting until the peripheral speed of the rotating body reaches a predetermined peripheral speed, and when the rotating body is in a relatively low temperature state, it is formed between the rotating body pair. An image forming apparatus having a heating device capable of realizing a rapid temperature rise of the nip portion can be provided.

Further, according to the fifteenth invention of the present application, after the power supply is started along with the start of rotation of the rotating body, when a predetermined time has elapsed from the start of the rotation or when the peripheral speed of the rotating body has reached the predetermined value. When the peripheral speed is reached, the power supply from the power supply source to the heating element is changed to a predetermined constant power, so that even when the rotating body is in a high temperature state, the peripheral speed of the rotating body is increased to the predetermined peripheral speed. And an image forming apparatus provided with a heating device in which overshooting of the heating element is prevented until the temperature reaches the threshold value.

According to a sixteenth aspect of the present invention,
Since the power supply at the start of rotation of the rotating body is determined based on the temperature detected by the temperature detecting body before the rotation of the rotating body, the temperature of the nip formed between the rotating body pair rises to the target heating temperature. It is possible to provide an image forming apparatus including a heating device capable of realizing rapid temperature increase in accordance with the temperature detected by the temperature detector before the rotation of the rotating body starts.

Further, according to the seventeenth invention of the present application, after the heating element is heated up to the transition temperature in accordance with the startup temperature increase control, the heating element is heated to the target heating temperature in accordance with the normal temperature elevation control. When the temperature of the rotating body is high, the transition temperature from the rising temperature rising control to the normal temperature rising control is determined based on the temperature detected by the temperature detecting body before the start of the rotating body. In this case, it is possible to provide an image forming apparatus including a heating device in which overshoot of the heating body is prevented until the peripheral speed of the rotating body reaches a predetermined peripheral speed.

According to the eighteenth aspect of the present invention,
After the heating element rises to the transition temperature in accordance with the startup temperature elevation control, the heating element rises to the target heating temperature in accordance with the normal temperature elevation control, and based on the elapsed time from the end of the previous series of heating processing. Since the transition temperature from the rising temperature raising control to the normal temperature raising control is determined, even when the rotating body is in a high temperature state, the heating body is kept rotating until the circumferential speed of the rotating body reaches a predetermined circumferential speed. An image forming apparatus including a heating device in which overshoot is prevented can be provided.

Further, according to the nineteenth aspect of the present invention, as a method for raising the heating target temperature of the heating body, the heating body is rapidly heated in accordance with the rising temperature rise control, and then the heating body is started up. The first method in which the heating element is heated to the target heating temperature in accordance with the normal temperature raising control in which the temperature is raised more slowly than in the temperature raising control, and the heating element is raised to the target heating temperature in accordance with only the normal temperature raising control. The second method of warming is predetermined, and according to the method selected from the first method and the second method according to the detected temperature of the temperature detecting body before the start of the rotating body,
Since the heating body is heated to the heating target temperature, even when the rotating body is in a high temperature state, a heating device that prevents overshooting of the heating body until the peripheral speed of the rotating body reaches a predetermined peripheral speed. An image forming apparatus provided with:

According to the twentieth invention of the present application,
As a method for raising the heating target temperature of the heating body, the heating body is rapidly heated according to the rising temperature rising control, and then the heating body is gradually warmed up according to the normal temperature rising control. The first method of raising the temperature to the heating target temperature,
And, a second method of raising the temperature of the heating body to the heating target temperature in accordance with only the normal temperature raising control is predetermined.
When the rotating body is in a high temperature state, the heating body is heated to the heating target temperature by the method selected from the first method and the second method according to the elapsed time from the end of the previous series of heating treatments. In this case, it is possible to provide an image forming apparatus including a heating device in which overshoot of the heating body is prevented until the peripheral speed of the rotating body reaches a predetermined peripheral speed.

Further, according to the twenty-first aspect of the present invention, as a method for raising the heating target temperature of the heating body, the heating body is rapidly heated in accordance with the startup temperature rise control, and then the heating body is heated. The first method of raising the temperature of the heating body to the target heating temperature in accordance with the normal temperature raising control in which the temperature is raised more slowly than in the startup temperature raising control, and the heating element is heated to the target heating temperature in accordance with only the normal temperature raising control The second method of raising the temperature is predetermined, and when the elapsed time from the end of the previous series of heating processing is equal to or longer than the reference elapsed time, the heating element is heated to the heating target temperature by the first method. When the elapsed time from the end of the previous series of heating processing is less than the reference elapsed time, the heating element is heated to the heating target temperature by the second method, and the supply at the end of the previous series of heating processing is performed. Electricity and heating value from previous heat treatment Since the heating target temperature and the power supply at the start of power supply in the second method are determined based on the temperature or the number of recording medium heating treatments, even when the rotating body is in a high temperature state, It is possible to provide an image forming apparatus provided with a heating device that prevents overshooting of the heating element until the peripheral speed reaches a predetermined peripheral speed.

Further, according to the twenty-second invention according to the present application, the ceramic heater is heated to the target heating temperature by the control described in the twelfth invention to the twenty-first invention according to the present application. Also, since the film and the pressure roller are heated by the ceramic heater maintained at the heating target temperature,
A heating device having the effects of the twelfth invention to the twenty-first invention according to the present application, wherein heating is performed such that a nip portion formed between a film and a pressure roller is rapidly heated. An image forming apparatus including the apparatus is provided.

Further, according to the twenty-third invention of the present application, the heating element which can be heated to the heating target temperature by the control described in the twelfth to twenty-first inventions of the present application. The fixing device having the fixing device fixes the unfixed image on the recording medium by performing a heating process on the recording medium carrying the unfixed image. Therefore, the twelfth invention to the twenty-first invention according to the present application are described below. An image forming apparatus including a fixing device having the effects of the present invention is provided.

According to the twenty-fourth invention of the present application, the heating element which can be heated to the target heating temperature by the control described in the twelfth to twenty-first inventions of the present application. The non-fixed image is subjected to heat treatment on the recording medium carrying the unfixed image, so that the unfixed image is hypothetically attached to the recording medium. According to another aspect of the present invention, there is provided an image forming apparatus including a hypothetical receiving device having the effects of the invention.

Further, according to the twenty-fifth invention according to the present application, the heating element which can be heated to the target heating temperature by the control described in the twelfth invention to the twenty-first invention according to the present application. The surface property reforming device having the property improves the surface properties of the recording medium carrying the fixed image by performing a heat treatment on the recording medium, so that the twelfth invention to the twenty-first invention according to the present application are described. An image forming apparatus provided with a surface property modifying device having the effects of the present invention is realized.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view illustrating a schematic configuration of an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic sectional view showing a schematic configuration of the fixing device of FIG.

FIG. 3 is a schematic sectional view showing a schematic configuration of the ceramic heater of FIG. 2;

FIG. 4 is a schematic block diagram showing a power supply path from a commercial power supply to the ceramic heater of FIG. 2;

FIG. 5 is an explanatory diagram of a power supply start timing from a commercial power supply to a ceramic heater according to the first embodiment of the present invention, wherein (A) is an explanatory diagram of the conventional power supply start timing. (B) is an explanatory diagram of the power supply start timing in the first embodiment.

FIG. 6 is a schematic diagram for explaining switching of an input wave number to a ceramic heater according to a second embodiment of the present invention, in which (a) illustrates an input to the ceramic heater when the ceramic heater is fully turned on. It is a figure which shows a wave number, On the other hand, (b) is a figure which shows the input to the ceramic heater of 8 [waves] of 15 [waves] fundamental wave number.

FIG. 7 is an example of an explanatory diagram relating to a startup temperature increase control according to a second embodiment of the present invention, and in particular, FIG.
6 is a control table showing the rising wave number input to the heating resistor in the conventional rising temperature rising control;
5 is a control table showing the rising wave number input to the heating resistor in the rising temperature rising control of the present embodiment.

FIG. 8 is another example of an explanatory diagram regarding the startup temperature increase control according to the second embodiment of the present invention.

FIG. 9 is an explanatory diagram relating to switching of a difference between a heating target temperature and a transition temperature according to the third embodiment of the present invention, and in particular, (A) shows a conventional set value of the transition temperature. FIG. 7B is a control table showing a set value of a transition temperature in the present embodiment.

FIG. 10 is a control table for P control according to a third embodiment of the present invention.

FIG. 11 is an explanatory diagram regarding switching of a difference between a heating target temperature and a transition temperature according to the fourth embodiment of the present invention, and in particular, FIG. 11A illustrates a heating target of the ceramic heater according to the embodiment; FIG. 6B is a control table until the temperature rises. On the other hand, FIG.
4 is a control table up to a heating target temperature increase of the ceramic heater when the temperature is [° C.] or more.

FIG. 12 is a graph showing a change in temperature of a heating body in a conventional temperature control.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laser printer (Image forming apparatus) 2 Latent image carrier 5 Fixing apparatus (Heating apparatus) 15 Ceramic heater (Heating body) 16 Film (Rotating body) 17 Pressure roller (Rotating body) 18 Thermistor temperature sensing element (Temperature detecting body) ) 19 holder 20 triac 21 commercial power supply 22 analog-digital conversion circuit 23 central processing unit (power supply control means) 15A substrate 15B heating resistor 15C protective layer

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H05B 3/14 G03G 21/00 372

Claims (25)

[Claims] 1. A recording medium carrying an unfixed image or a fixed image passes between a pair of rotatable rotating members which are pressed against each other and are supplied with electric power from a power supply source to be turned on by the heating member. Heat-treat the medium,
In a fixing device including a temperature detector that detects the temperature of the heating element, power supply is set to start when a predetermined time has elapsed from the start of rotation of the rotating body or when the peripheral speed of the rotating body has reached a predetermined peripheral speed. A heating device, characterized in that: 2. The heating apparatus according to claim 1, wherein the power supply start timing is determined based on a detected temperature of the temperature detector before rotation of the rotating body. 3. The heating apparatus according to claim 1, wherein the power supply start timing is determined based on an elapsed time from the end of a previous series of heating processes. 4. A recording medium carrying an unfixed image or a fixed image is passed between a pair of rotatable rotating members which are pressed against each other and are supplied with power from a power supply source, and the recording medium is turned on by a heating member. Heat-treat the medium,
In a fixing device provided with a temperature detector that detects the temperature of the heating element, the supply power is started at the start of rotation of the rotating body, and then after a predetermined time has elapsed from the start of rotation or when the peripheral speed of the rotating body has reached the predetermined peripheral speed. A heating device which is set so as to be changed to a predetermined constant power at the time of arrival. 5. The heating device according to claim 4, wherein the power supply at the start of rotation of the rotating body is determined based on a temperature detected by the temperature detector before the rotation of the rotating body starts. 6. A recording medium carrying an unfixed image or a fixed image is passed between a pair of rotatable rotating members which are pressed against each other, and the recording medium is turned on by receiving a power supply from a power supply source. Heat-treat the medium,
In a heating device provided with a temperature detector that detects the temperature of the heating element, the heating element rises rapidly with the start of the rotating body, rises in temperature according to the temperature rise control, and then starts up the heating body more than at the time of temperature rise control. The temperature is raised to the heating target temperature in accordance with the normal temperature rise control that gradually raises the temperature.The transition temperature from the startup temperature rise control to the normal temperature rise control depends on the temperature of the temperature detector before the start of the rotating body. A heating device set to be determined based on a detected temperature. 7. A heating element which receives power from a power supply source and turns on while allowing a recording medium carrying an unfixed image or a fixed image to pass between a pair of rotatable rotating members which are pressed against each other and are turned on. Heat-treat the medium,
In a heating device provided with a temperature detector that detects the temperature of the heating element, the heating element is heated up rapidly according to the startup temperature elevation control, and then is heated up more slowly than at the time of the startup temperature elevation control. The temperature is raised to the heating target temperature in accordance with the temperature control, and the transition temperature from the startup temperature raising control to the normal temperature raising control is determined based on the elapsed time from the end of the previous series of heating processes. A heating device characterized by being set. 8. A recording medium carrying an unfixed image or a fixed image is passed between a pair of rotatable rotating members which are pressed against each other, and are supplied with electric power from a power supply source to be turned on by the heating member. Heat-treat the medium,
In a heating device equipped with a temperature detector that detects the temperature of the heating element, as a method of elevating the target heating temperature of the heating element, the temperature of the heating element is rapidly increased in accordance with the startup temperature elevation control, and then the heating element is activated and heated. The first method of raising the temperature of the heating element to the target heating temperature in accordance with the normal temperature raising control in which the temperature is raised more slowly than the control, and the method of raising the temperature of the heating element to the target heating temperature in accordance with only the normal temperature raising control A second method is predetermined, and the heating target is heated to a target heating temperature by a method selected from the first method and the second method in accordance with the detected temperature of the temperature detector before the start of the rotating body. A heating device characterized in that the temperature is set to rise. 9. A recording medium carrying a non-fixed image or a fixed image passing between a pair of rotatable rotating members which are pressed against each other and illuminated by receiving power from a power supply source. Heat-treat the medium,
In a heating device equipped with a temperature detector that detects the temperature of the heating element, as a method of elevating the target heating temperature of the heating element, the temperature of the heating element is rapidly increased in accordance with the startup temperature elevation control, and then the heating element is activated and heated. The first method of raising the temperature of the heating element to the target heating temperature in accordance with the normal temperature raising control in which the temperature is raised more slowly than the control, and the method of raising the temperature of the heating element to the target heating temperature in accordance with only the normal temperature raising control A second method is predetermined, and the heating element is heated to the heating target temperature by a method selected from the first method and the second method according to the elapsed time from the end of the previous series of heating processes. A heating device set to be heated. 10. A recording medium carrying an unfixed image or a fixed image is passed between a pair of rotatable rotating members which are pressed against each other and received by a power supply from a power supply source. Heat-treat the medium,
Also, in a heating device provided with a temperature detector for detecting the temperature of the heating element, as a method of elevating the target heating temperature of the heating element, the heating element is rapidly heated in accordance with the startup temperature elevation control, and then the heating element is activated. The first method in which the heating element is heated to the heating target temperature in accordance with the normal heating control in which the temperature is raised more slowly than in the heating control, and the heating element is heated to the heating target temperature in accordance with only the normal heating control. The second method of squeezing is predetermined, and the heating element is heated to the heating target temperature by the first method when the elapsed time from the end of the previous series of heating processing is equal to or longer than the reference elapsed time, When the elapsed time from the end of the previous series of heating processing is less than the reference elapsed time, the temperature is raised to the heating target temperature by the second method, and the heating target temperature and the power in the second method are increased. At the start of supply The power supply is set so as to be determined based on the power supply at the end of the previous series of heating processing and the heating target temperature or the number of recording medium heating processing in the previous series of heating processing. Heating equipment. 11. One rotating body is an endless belt-shaped heat-resistant film, the other rotating body is a cylindrical or substantially cylindrical pressing roller, and the heating body is one surface of a substrate mainly made of ceramics. A heating resistor provided with power supply from a power supply source to generate heat, and a ceramic heater having a temperature detector abutting on or adjacent to the other surface of the substrate. The heating device according to claim 10. 12. A latent image formed and carried on a latent image carrier is made a visible image with a developer, and then the visible image is transferred to a recording medium to form an unfixed image on the recording medium.
An image forming apparatus for recording the unfixed image as a fixed image on the recording medium, comprising the heating device according to claim 1. 13. The image forming apparatus according to claim 12, wherein the power supply start timing is determined based on a detected temperature of the temperature detector before rotation of the rotating body. 14. The image forming apparatus according to claim 12, wherein the power supply start timing is determined based on an elapsed time from the end of a previous series of heating processes. 15. A latent image formed and carried on the latent image carrier is made visible by a developer, and then the visible image is transferred to a recording medium to form an unfixed image on the recording medium.
An image forming apparatus for recording the unfixed image as a fixed image on the recording medium, comprising the heating device according to claim 4. 16. The image forming apparatus according to claim 15, wherein the power supply at the start of rotation of the rotating body is determined based on the temperature detected by the temperature detector before the rotation of the rotating body starts. 17. A latent image formed and carried on a latent image carrier is made visible by a developer, and then the visible image is transferred to a recording medium to form an unfixed image on the recording medium.
An image forming apparatus for recording the unfixed image as a fixed image on the recording medium, comprising the heating device according to claim 6. 18. A latent image formed and carried on a latent image carrier is made visible with a developer, and then the visible image is transferred to a recording medium to form an unfixed image on the recording medium.
An image forming apparatus for recording the unfixed image as a fixed image on the recording medium, comprising the heating device according to claim 7. 19. A latent image formed and carried on a latent image carrier is made visible by a developer, and then the visible image is transferred to a recording medium to form an unfixed image on the recording medium.
An image forming apparatus for recording the unfixed image as a fixed image on the recording medium, comprising the heating device according to claim 8. 20. A latent image formed and carried on a latent image carrier is converted into a visible image by a developer, and then the visible image is transferred to a recording medium to form an unfixed image on the recording medium.
An image forming apparatus for recording the unfixed image as a fixed image on the recording medium, comprising the heating device according to claim 9. 21. A latent image formed and carried on a latent image carrier is formed into a visible image by a developer, and then the visible image is transferred to a recording medium to form an unfixed image on the recording medium.
An image forming apparatus for recording the unfixed image as a fixed image on the recording medium, comprising the heating device according to claim 10. 22. One rotating body is an endless belt-shaped heat-resistant film, the other rotating body is a cylindrical or substantially cylindrical pressing roller, and the heating body is one surface of a substrate mainly made of ceramics. 13. A ceramic heater in which a heating resistor which receives power supply from a power supply source and generates heat is provided, and a temperature detector is in contact with or close to the other surface of the substrate. 22. The heating device according to 21. 23. The fixing device according to claim 12, wherein the heating device is configured to fix the unfixed image on the recording medium by performing a heating process on the recording medium carrying the unfixed image. The image forming apparatus as described in the above. 24. The heating device according to claim 12, wherein the heating device performs a heating process on the recording medium carrying the unfixed image, thereby forming an assumed fixing device on the recording medium. Item 23. An image forming apparatus according to Item 22. 25. The heating device according to claim 12, wherein the heating device performs a heating process on the recording medium carrying the unfixed image to improve the surface properties of the recording medium. Item 23. An image forming apparatus according to Item 22.