JPH11167309A - Temperature control device, fixing device, and image forming apparatus having the same - Google Patents

Abstract

(57) Abstract: The present invention relates to a fixing device in which a temperature ripple, which is a difference between a maximum value and a minimum value of a temperature of a fixing roller during a step of maintaining the fixing roller at a target temperature, is reduced. It is an object of the present invention to provide an image forming apparatus having this. SOLUTION: In accordance with a detected temperature of a thermistor 38 and a detected temperature of a thermistor 39, a switch means switches between energization and cutoff from a commercial power supply to a halogen heater 37, so that the fixing roller 10a reaches a target temperature. Raise and maintain temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical or substantially cylindrical member having an outer peripheral surface formed on a sheet-like recording material carrying an unfixed image and conducting heat from a heating means which generates heat by supplying electricity from a commercial power supply. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature control device for controlling the temperature of a rotatable fixing roller, a fixing device, and an image forming apparatus having the same.

[0002]

2. Description of the Related Art Conventionally, as such a fixing device, a halogen heater which generates heat when energized by a commercial power supply as a heating means, a cylindrical or substantially cylindrical rotatable fixing roller, 2. Description of the Related Art A fixing device including a rotatable pressure roller having a cylindrical shape, a substantially cylindrical shape, a columnar shape, or a substantially columnar shape is known and is in practical use.

[0003] A fixing roller provided in such a fixing device includes:
An outer peripheral surface of a cylindrical or substantially cylindrical core metal mainly composed of aluminum or the like is coated with an elastic layer mainly composed of silicone rubber or the like, and is rotatably supported by a fixing device body or the like. I have.

In the hollow portion of the fixing roller, a halogen heater is disposed along the axial direction of the fixing roller. On the outer peripheral surface of the fixing roller, a thermistor temperature sensor for detecting the temperature of the fixing roller (hereinafter referred to as a sensor) is provided. , A thermistor) is disposed in contact with or in proximity to the power supply, so that, depending on the temperature detected by the thermistor, a switch is made between power supply from the commercial power supply to the halogen heater and cutoff between the commercial power supply and the halogen heater. The temperature of the fixing roller is raised and maintained at the target temperature by ON / OFF control of switching means.

A pressure roller provided in such a fixing device is
A nip portion for performing a fixing process on a recording material carrying an unfixed image is formed by being pressed against a fixing roller from a pressing mechanism provided in an image forming apparatus having a fixing device. Thus, when one of the fixing roller and the pressing roller is rotationally driven by the driving mechanism provided in the image forming apparatus, the other roller is driven by the rotation of the one roller. .

Therefore, in such a fixing device, while the recording material bearing the unfixed image is passed through the nip portion, the recording material is heated by the halogen heater and pressed by the pressure contact between the fixing roller and the pressure roller. The unfixed image was recorded by melting and infiltrating into the recording material.

[0007]

However, in such a fixing device, the power supply from the commercial power supply to the halogen heater is turned on in accordance with the detected temperature of a thermistor disposed in contact with or close to the outer peripheral surface of the fixing roller. / OFF control, there is a possibility that the thermal response of the thermistor may be delayed due to the heat capacity of the elastic layer of the fixing roller or the like. Therefore, as shown in FIG. O
It has been difficult to reduce the temperature ripple, which is the difference between the maximum value and the minimum value of the temperature detected by the thermistor during the process of maintaining the fixing roller at the target temperature by the FF control.

FIG. 6 is a graph showing an example of a change in the temperature detected by the thermistor during the process of maintaining the fixing roller at the target temperature.

Accordingly, the first object of the present invention is to provide a temperature control device capable of reducing a temperature ripple which is a difference between a maximum value and a minimum value of the temperature of the fixing roller during a step of maintaining the fixing roller at a target temperature. The purpose of.

The present invention also provides a fixing device in which the temperature ripple, which is the difference between the maximum value and the minimum value of the temperature of the fixing roller during the step of maintaining the fixing roller at the target temperature, is reduced. The purpose of.

Further, the present invention provides an image forming apparatus having a fixing device in which a temperature ripple, which is a difference between a maximum value and a minimum value of the temperature of the fixing roller during a step of maintaining the fixing roller at a target temperature, is reduced. Is the third purpose.

[0012]

According to the present invention, the first object is to conduct heat from a heating means which generates heat by supplying electricity from a commercial power supply to a sheet-like recording material carrying an unfixed image. A temperature control device for controlling the temperature of a cylindrical or substantially cylindrical rotatable fixing roller having an outer peripheral surface formed thereon, wherein the fixing roller is a cylindrical or substantially cylindrical core metal. Heating means is disposed in the hollow portion while being covered with a coating layer mainly composed of an elastic material on the outer peripheral surface, and first temperature detecting means for detecting the temperature of the outer peripheral surface of the fixing roller, A temperature control device comprising: switch means for switching between energization and interruption of the heating means from the commercial power supply, and a second temperature detection means for detecting the temperature of the core metal, One of the temperature detecting means Switch means in accordance with the detection value of the knowledge value and the second temperature detecting means is achieved by the first invention of being set to switch to one of the current supply and interruption of the heating unit from the commercial power source.

According to the present application, the first object is to
In the first invention according to the present application, the first temperature detecting means is arranged to be in contact with or close to the outer peripheral surface of the fixing roller to detect one or more temperature detectors for detecting the temperature of the outer peripheral surface. This is also achieved by the second invention that is a sensor.

Further, according to the present application, the first object is to provide the first or second invention according to the present application, wherein
The second temperature detecting means is also achieved by the third invention in that the second temperature detecting means is a temperature detecting sensor that detects the temperature of the core metal by being disposed in contact with or close to the outer peripheral surface or the inner peripheral surface of the core metal. You.

According to the present application, the first object is to
In any one of the first to third inventions according to the present application, when the detected value of the first temperature detecting means is equal to or more than the target value of the outer peripheral surface of the fixing roller, the commercial power supply and the heating means are shut off. When the detected value of the first temperature detecting means is equal to or less than the target value of the outer peripheral surface, the commercial power supply is determined according to the comparison between the second temperature detecting body and the target value of the core metal of the fixing roller. The present invention is also achieved by the fourth invention in which the switch means is switched to either one of energization to the heating means and interruption to the heating means.

Further, according to the present application, the first object is that in any one of the first to fourth inventions according to the present application, the target value of the core metal of the fixing roller is the outer circumference of the fixing roller. The present invention is also achieved by the fifth invention in which the setting is made in accordance with the target value of the surface.

According to the present application, the second object is to
A fixing device configured to perform a fixing process on a sheet-shaped recording material carrying an unfixed image by heating a heating unit, wherein an elastic material is a main component on an outer peripheral surface of a cylindrical or substantially cylindrical core. A rotatable fixing roller covered with a coating layer and having a heating means disposed in a hollow portion of the cored bar; and a cylindrical or substantially cylindrical cylinder pressed against the fixing roller via the recording material. And a temperature control device according to a first aspect of the present invention, wherein the temperature of the fixing roller is controlled by a temperature control device according to the first invention of the present application. The invention is achieved by the invention of (1).

Further, according to the present application, the second object is that in the sixth invention according to the present application, the first temperature detecting means is disposed in contact with or close to the outer peripheral surface of the fixing roller. Accordingly, the present invention is also achieved by the seventh invention in which the temperature sensor is one or a plurality of temperature detectors for detecting the temperature of the outer peripheral surface.

According to the present application, the second object is to
In the sixth invention or the seventh invention according to the present application, the second temperature detecting means detects the temperature of the core metal by being placed in contact with or close to the outer peripheral surface or the inner peripheral surface of the core metal. The present invention is also achieved by the eighth invention in which the temperature sensor is a temperature sensor.

Further, according to the present application, the second object is that in any one of the sixth to eighth inventions according to the present invention, the detection value of the first temperature detecting means is a value of the fixing roller. When it is equal to or more than the target value of the outer peripheral surface, the switch means is switched so as to shut off the commercial power supply and the heating means, and when the detected value of the first temperature detecting means is equal to or less than the target value of the outer peripheral surface, the second temperature is set. The invention is also achieved by the ninth invention in which the switch means is switched to either one of energization and cutoff from the commercial power supply to the heating means in accordance with the comparison between the target value of the core metal of the detection body and the fixing roller. You.

According to the present application, the second object is to
In any one of the sixth invention to the ninth invention according to the present application, a tenth aspect is that the target value of the core metal of the fixing roller is set to be determined according to the target value of the outer peripheral surface of the fixing roller. It is also achieved by the invention.

Further, according to the present application, the third object is to provide a temperature control device according to the first invention of the present application,
This is achieved by an eleventh invention that includes the fixing device according to the sixth invention of the present application.

According to the present application, the third object is to
In the eleventh invention according to the present application, the first temperature detecting means is arranged to abut on or be close to the outer peripheral surface of the fixing roller to detect one or more temperatures for detecting the temperature of the outer peripheral surface. The present invention is also achieved by a twelfth invention that is a detector.

Further, according to the present application, the third object is as described in the eleventh invention or the twelfth invention according to the present application, wherein the second temperature detecting means comprises an outer peripheral surface of a cored bar or The invention is also achieved by a thirteenth invention in which the temperature sensor is a temperature detection sensor that detects the temperature of the cored bar by being placed in contact with or close to the inner peripheral surface.

According to the present application, the third object is to
In any one of the eleventh to thirteenth inventions according to the present application, when the detection value of the first temperature detection unit is equal to or more than the target value of the outer peripheral surface of the fixing roller, the commercial power supply and the heating unit are connected. When the detection value of the first temperature detecting means is equal to or less than the target value of the outer peripheral surface, the switch means is switched so as to cut off the second temperature detecting body and the target value of the core metal of the fixing roller. The present invention is also achieved by a fourteenth invention in which the switch means is switched to either one of energization and cutoff from the commercial power supply to the heating means.

Further, according to the present application, the third object is to provide the fixing roller according to any one of the eleventh to fourteenth inventions, wherein the target value of the core metal of the fixing roller is The invention is also attained by the fifteenth invention that is set so as to be determined according to the target value of the outer peripheral surface.

That is, in the first invention according to the present application, the switch means switches from the commercial power supply to the heating means according to the detection value of the first temperature detection means and the detection value of the second temperature detection means. By switching to either energization or interruption, the temperature of the fixing roller is raised and maintained at the target temperature.

In the second invention according to the present application,
The switch means switches from the commercial power supply to the heating means in accordance with each detection value of one or more temperature detection sensors disposed in contact with or close to the outer peripheral surface of the fixing roller and the detection value of the second temperature detection means. By switching to either energization or interruption, the temperature of the fixing roller is raised and maintained at the target temperature.

Further, in the third invention according to the present application, the temperature detected by the first temperature detecting means and the temperature detection disposed in contact with or close to the outer peripheral surface or the inner peripheral surface of the cored bar. The switch means switches between energization and cutoff from the commercial power supply to the heating means in accordance with the detection value of the sensor, thereby raising and maintaining the fixing roller at the target temperature.

In the fourth invention according to the present application,
When the detected value of the first temperature detecting means is equal to or more than the target value of the outer peripheral surface of the fixing roller, the switch means is switched so as to shut off the commercial power supply and the heating means, and the detected value of the first temperature detecting means is equal to the outer peripheral value. When the temperature is equal to or less than the target value of the surface, the switch means is switched to one of energization and cutoff from the commercial power supply to the heating means in accordance with the comparison between the second temperature detector and the target value of the core metal of the fixing roller. Thereby, the temperature of the fixing roller is raised and maintained at the target temperature.

Further, in the fifth invention according to the present application, the target value of the core metal of the fixing roller is determined according to the target value of the outer peripheral surface of the fixing roller.

In the sixth invention according to the present application,
The switch unit switches between one of energization and interruption of the heating unit from the commercial power supply according to the detection value of the first temperature detection unit and the detection value of the second temperature detection unit. The temperature of the rotatable fixing roller is raised and maintained at the target temperature.

In the seventh invention according to the present application,
The switch means switches from the commercial power supply to the heating means in accordance with each detection value of one or more temperature detection sensors disposed in contact with or close to the outer peripheral surface of the fixing roller and the detection value of the second temperature detection means. By switching to either energization or interruption, the temperature of the rotatable fixing roller provided in the fixing device is raised and maintained at the target temperature.

Further, in the eighth invention according to the present application, the temperature detected by the first temperature detecting means and the temperature detection disposed in contact with or close to the outer peripheral surface or the inner peripheral surface of the cored bar. The switch means switches between energization and interruption of the heating means from the commercial power supply in accordance with the detection value of the sensor, thereby raising and maintaining the temperature of the rotatable fixing roller provided in the fixing device to the target temperature. Is performed.

In the ninth invention according to the present application,
When the detected value of the first temperature detecting means is equal to or more than the target value of the outer peripheral surface of the fixing roller, the switch means is switched so as to cut off the commercial power supply and the heating means, When the temperature is equal to or less than the target value of the surface, the switch means is switched to one of energization and cutoff from the commercial power supply to the heating means in accordance with the comparison between the second temperature detector and the target value of the core metal of the fixing roller. Accordingly, the temperature of the rotatable fixing roller provided in the fixing device is raised to and maintained at the target temperature.

Further, in the tenth invention according to the present application, the target value of the core metal of the fixing roller is determined according to the target value of the outer peripheral surface of the rotatable fixing roller provided in the fixing device. .

In the eleventh invention according to the present application, the switch is operated in accordance with the detection value of the first temperature detection means and the detection value of the second temperature detection means provided in the temperature control device. The unit switches the current from the commercial power supply to the energization to the heating unit or cuts off the heating unit, thereby raising and maintaining the temperature of the rotatable fixing roller provided in the fixing device to the target temperature.

In the twelfth invention according to the present application, the temperature control device is provided so as to be in contact with or close to the outer peripheral surface of the rotatable fixing roller provided in the fixing device. The switch means switches between one of energization and cutoff from the commercial power supply to the heating means in accordance with each detection value of one or more temperature detection sensors and the detection value of the second temperature detection means, thereby fixing the image. The temperature of the roller is raised and maintained at the target temperature.

Further, in the thirteenth invention according to the present application, the detection value of the first temperature detecting means provided in the temperature control device and the rotatable fixing roller provided in the fixing device are constituted. The switch means switches between energization and cutoff from the commercial power supply to the heating means in accordance with a detection value of a temperature detection sensor arranged in contact with or close to the outer peripheral surface or the inner peripheral surface of the cored bar. Accordingly, the temperature of the rotatable fixing roller provided in the fixing device is raised and maintained at the target temperature.

Further, in the fourteenth invention according to the present application, the detection value of the first temperature detecting means provided in the temperature control device is determined by detecting the outer periphery of the rotatable fixing roller provided in the fixing device. When it is equal to or more than the target value of the surface, the switch means is switched so as to shut off the commercial power supply and the heating means. When the detection value of the first temperature detection means is equal to or less than the target value of the outer peripheral surface, the second temperature detection is performed. By switching the switch means to either energize or cut off from the commercial power supply to the heating means according to the comparison between the target value of the core metal of the body and the fixing roller, the rotatable fixing roller provided in the fixing device is switched. Raise and maintain the target temperature.

Further, according to the fifteenth invention of the present application, the target value of the core metal of the fixing roller is determined according to the target value of the outer peripheral surface of the rotatable fixing roller provided in the fixing device. You.

[0042]

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

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

FIG. 1 is a schematic cross-sectional view showing a schematic configuration of a digital type full-color copying machine (hereinafter, abbreviated as a copying machine) as an example preferably showing the image forming apparatus of the present embodiment.

After reading the image information of the document D (including characters and the like drawn on the document D), the copying machine reads the image information.
A digital color image reader unit I (hereinafter, referred to as a reader unit) configured to perform image processing such as color separation of the read image information for each color of yellow, cyan, magenta, and black, and output the processed image information. Then, after forming an image in accordance with the output for each color from the reader unit I, the image formed in accordance with each color is superimposed on the recording material P to carry the image corresponding to the image information of the document D. It is mainly divided into a digital color image printer section II (hereinafter, abbreviated as printer section II) which is formed on the recording material P and records.

The reader unit I of the copier includes an original platen glass 12a on which the original D is placed, an exposure lamp 12b for exposing and scanning the original D while moving from one light in the horizontal direction to the other direction, and an exposure lamp 12b. A plurality of mirrors 12c for reflecting the light reflected on the document D by the exposure scanning further in a prescribed direction, a lens 12d for collecting the light reflected from the plurality of mirrors 12c, and the above-mentioned light collected by the lens 12d. The reflected light is composed of a full-color sensor 12e that outputs a color-separated image signal corresponding to each color of yellow, cyan, magenta, and black, and the like, and the color of each color output from the full-color sensor 12e The color-separated image signal is amplified by an amplification circuit (not shown) constituting the reader unit I, and the video signal constituting the reader unit I is processed. After having been subjected to image processing by O processing unit (not shown), and is output to the printer unit II.

The printer unit II of the copier includes a rotatable photosensitive drum 1 having a cylindrical or substantially cylindrical shape or a cylindrical or substantially cylindrical shape, and a color image output from the reader unit I and subjected to amplification processing and image processing. Exposure device 3 that forms an electrostatic latent image on the outer peripheral surface of photosensitive drum 1 according to image information of document D by performing an exposure processing step according to the decomposed image signal
A developing device 4 for developing an electrostatic latent image with a yellow toner, a cyan toner, a magenta toner, and a black toner as a developer; and a yellow toner image, a cyan toner image, and a magenta toner image formed on the outer peripheral surface. And a transfer device 5 for transferring the black toner image onto the recording material P
A paper feeder 8 for conveying the recording material P to the transfer device 5, a fixing device 10 for performing a fixing process on the recording material P carrying an unfixed image, and a copying machine And a paper discharge unit 11 that is discharged from the printer and stacked.

The photosensitive drum 1 provided in the printer unit II
Is composed of a cylindrical or substantially cylindrical or cylindrical or substantially cylindrical substrate 1a containing aluminum as a main component, and an inner peripheral surface of which is coated with an OPC (organic semiconductor). The driving mechanism (not shown) provided in the main body of R
It is driven to rotate in one direction.

Around the photosensitive drum 1, a primary charger 2 for charging the outer peripheral surface of the photosensitive drum 1 to a specified potential distribution before the exposure processing by the exposure device 3, and after the transfer processing to one recording material P, A cleaning device 6 for collecting the residue on the outer peripheral surface, and a pre-exposure lamp 7 for removing electricity from the outer peripheral surface after the transfer processing are arranged.

Around the photosensitive drum 1, a potential sensor Sl for detecting a potential distribution on the outer peripheral surface of the photosensitive drum 1 is disposed between the primary charger 2 and the developing device 4 in the direction of arrow R1. A density sensor S2 for detecting the density of the toner image formed on the outer peripheral surface is disposed between the developing device 4 and the transfer device 5 in the direction of arrow R1.

In the present embodiment, the primary charger 2 disposed around the photosensitive drum 1 has a shield 2a having an opening at a portion facing the photosensitive drum 1, and a photosensitive drum 2a inside the shield 2a. A discharge wire 2b arranged in parallel with the axial direction of the body drum 1; and a grid 2c attached to the opening to adjust the potential distribution on the outer peripheral surface of the photosensitive drum 1; A corona charger is used to charge the outer peripheral surface to a specified potential distribution by applying a bias from an external power supply (not shown) provided in the power supply.

The cleaning device 6 disposed around the photosensitive drum 1 includes a cleaning blade 6a for scraping off the residue on the outer peripheral surface of the photosensitive drum 1 after the transfer process to one recording material P, and a cleaning blade 6a. A cleaning container 6b for collecting the residue scraped off by 6a.

The pre-exposure lamp 7 arranged around the photosensitive drum 1 is arranged on the upstream side of the primary charger 2 with respect to the direction of the arrow R1, and the photosensitive drum 1 from which the residue has been collected by the cleaning device 6. Unnecessary charges on the outer peripheral surface are removed.

Exposure device 3 provided in printer unit II
A laser output unit (not shown) that blinks a laser E in response to the amplified and image-processed color separation image signal output from the reader unit I, and a laser E from the laser output unit in a specified direction. A rotatable polygon mirror 3a that reflects toward the photosensitive drum 1, a lens 3b that focuses the laser E reflected from the polygon mirror 3a, and a mirror 3c that reflects the laser E focused by the lens 3b toward the photosensitive drum 1. In the original embodiment, an electrostatic latent image corresponding to each color of yellow, cyan, magenta, and black is formed in this order on the photosensitive drum 1 based on the image of the original.
Is formed on the outer peripheral surface.

Developing device 4 provided in printer unit II
Is a developing device 4Y that supplies the yellow toner to the developing process,
A developing unit 4C for developing the cyan toner in the developing process, a developing unit 4M for developing the magenta toner in the developing process, and four developing units 4Bk for developing the black toner in the developing process; , 4M, and 4Bk are arranged around the photosensitive drum 1 in order from the upstream side in the Rl direction, and carry toner corresponding to each color, and are formed on the outer peripheral surface of the photosensitive drum 1 for electrostatic latent images. The yellow toner includes a rotatable developing sleeve 4a having a cylindrical or substantially cylindrical shape or a cylindrical or substantially cylindrical shape having an outer peripheral surface formed thereon for attaching to an image, and a rotatable eccentric cam 4b. During the development process, the developing sleeve 4a of the developing device 4Y is brought close to the outer peripheral surface of the photosensitive drum 1 by the eccentric cam 4b of the corresponding developing device 4Y. On the other hand, the developing devices 4C, 4M, 4Bk
The developing sleeve 4a is detached from the outer peripheral surface of the photosensitive drum 1 to perform a developing process corresponding to each color.

Transfer device 5 provided in printer unit II
Is a cylindrical or substantially cylindrical rotatable transfer drum 5a on which an outer peripheral surface for supporting the recording material P is formed, and a toner image for each color formed on the outer peripheral surface of the photosensitive drum 1. A transfer charger 5b for transferring to the recording material P;
Charger 5 for adsorbing the toner on the outer peripheral surface of the transfer drum 5a
c, a rotatable suction roller 5d arranged to face the suction charger 5c via the transfer drum 5a, a charger 5e for charging the transfer drum 5a and the like from the inside, and charging the transfer drum 5a and the like from the outside. And a charging device 5f.

The transfer drum 5a of the transfer device 5 is driven to rotate in the direction of arrow R5 by a drive mechanism (not shown) provided in the main body of the copying machine. A recording material carrying sheet 5g mainly composed of a dielectric is stretched integrally with the outer peripheral surface in the formed opening, so that the recording material P is carried on the outer peripheral surface. .

In the present embodiment, the recording material carrying sheet 5g integrally stretched on the outer peripheral surface of the transfer drum 5a is as follows.
A dielectric sheet typified by a polycarbonate film or the like is employed.

A separating device 9 for separating the transfer-processed recording material P from the outer peripheral surface of the transfer drum 5a is arranged around the transfer drum 5a.
A separating charger 9a for charging the recording material P adsorbed on the outer peripheral surface for separation, a separating claw 9b for separating the recording material P from the outer peripheral surface, and a separating claw 9b for separating the recording material P from the outer peripheral surface. Separation push-up roller 9 that pushes up recording material P 9
c.

Paper feed transport unit 8 provided in printer unit II
Are a plurality of paper feed cassettes 8a for storing the recording materials P by stacking the recording materials P, and a rotatable paper feed roller for taking out the recording materials P from each paper feed cassette 8a and feeding the recording materials P toward the transfer device 5. 8b, and a rotatable registration roller 8c that conveys the recording material P from each paper feed cassette 8a to the transfer device 5 at a predetermined timing or the like. The recording material P of the adjusted size is fed from the sheet feeding unit 8 to the transfer device 5 and is conveyed.

Paper discharge unit 11 provided in printer unit II
Is a transport path switching guide 11a that is disposed downstream of the fixing device 10 with respect to the transport direction of the recording material P, and switches the transport of the recording material P after the fixing process to either inside or outside the apparatus; A rotatable discharge roller 11b for discharging the recording material P out of the machine, a discharge tray 11c for loading and supporting the recording material P discharged from the copying machine by the discharge roller 11b, A conveying vertical path 11d through which a recording material P on which the image has been formed and the other surface of which is to be image-formed (hereinafter, referred to as a recording material P on which both surfaces are formed) passes, and an image is formed on both surfaces. A reversing path 11e for passing the recording material P in preparation for reversing, a loading member 11f for temporarily loading the recording material P on which images are to be formed on both sides in preparation for reversing, and a recording material P for forming images on both surfaces. Ready for image formation again Intermediate tray 11 for temporarily accommodating
g, rotatable transport rollers 11h and 11i for transporting the recording material P on which images are formed on both surfaces passing through the transport vertical path 11d in a predetermined direction, and reversing the recording material P on which images are formed on both surfaces. Rotatable reversing roller 11j
And are arranged.

Next, an outline of a series of image forming steps in the copying machine will be described. In the following description, a copy machine adopting a method of forming a full-color image of four colors in the order of yellow, cyan, magenta, and black will be described.

First, in the reader unit I, the image information of the original D placed on the original platen glass 12a is
After the exposure scanning of 2b, a color-separated image signal (hereinafter, referred to as a yellow image signal) corresponding to yellow from the full-color sensor 12e is subjected to amplification processing by an amplifier circuit, image processing by a video processing unit, and the like. Output to the device 3.

On the other hand, in the printer section II, the outer peripheral surface of the photosensitive drum 1, which is rotationally driven in the direction of the arrow Rl by the driving mechanism, is charged to a specified potential distribution by the primary charger 2 at a predetermined timing or the like. Later, Reader I
The laser E is blinked from the laser output unit of the exposure means 3 in response to the yellow image signal output from the device, and a charged portion (hereinafter referred to as a charged area) of the outer peripheral surface via the polygon mirror 3a or the like. .), The charged area is discharged, and an electrostatic image corresponding to the yellow image signal is formed.

Next, a developing unit 4Y is disposed at a position for performing a predetermined developing process (hereinafter, referred to as a developing position), and the other developing units 4C, 4M, and 4Bk are retracted from the developing position. The electrostatic latent image formed on the outer peripheral surface of the photosensitive drum 1 according to the yellow image signal is visualized as a yellow toner image by the yellow toner of the developing device 4Y.

Next, the recording material P on which an image corresponding to the image information of the document D is formed is supplied from, for example, a sheet feeding cassette 8a containing a recording material P of a size suitable for the image information to a sheet feeding roller 8b and a sheet feeding roller 8b. The transfer drum 5a is conveyed to the transfer drum 5a at a predetermined timing via the registration roller 8c and the like, is wound around the outer peripheral surface of the transfer drum 5a by the suction charger 5c and the suction roller 5d, and the transfer drum 5a is driven to rotate in the direction of arrow R5. Accordingly, the yellow toner image formed on the outer peripheral surface of the photosensitive drum 1 is transferred by the transfer charger 5b.

On the other hand, after the transfer process, the photosensitive drum 1 is subjected to the residual collection by the cleaning unit 6 and the charge removal by the pre-exposure lamp 7, and then the color separation corresponding to the cyan output from the full color sensor 12e. In order to prepare for the formation of an electrostatic latent image based on an image signal, the outer peripheral surface of the photosensitive drum 1 is again charged to a specified potential distribution by the primary charger 2.

Therefore, the process from reading of the image information of the document D by the reader unit I to the transfer process to the recording material P carried on the outer peripheral surface of the transfer drum 5a, and the photosensitive drum 1 by the primary charger 2 The process from the charging process to the specified potential distribution on the outer peripheral surface of the outer peripheral surface to the collection of the residue on the outer peripheral surface after the transfer process and the charge removal is repeated for the color separation information corresponding to each color of cyan, mass center, and black. As a result, an image obtained by superimposing the four color toner images synchronously, that is, an image corresponding to the image information of the document D (hereinafter, referred to as a full color image) is formed on the outer peripheral surface of the transfer drum 5a. The recording material P is carried on the wound recording material P.

The recording material P carrying an unfixed full-color image (hereinafter referred to as an unfixed image) is separated from the outer peripheral surface of the transfer drum 5a by a separation charger 9a and a separation claw 9b and the like. P is conveyed to the fixing device 10 with the unfixed image carrying surface of the
The fixing process is performed by heating and pressurizing in the above.

Next, the recording material P on which the fixing process has been performed is discharged out of the apparatus by discharge rollers 11 b and the like, and is discharged from the discharge tray 11.
c, or when images are formed on one surface and image formation is performed on the other surface,
The sheet is once guided to the reversing path 11e by being conveyed into the apparatus by the conveyance path switching guide 11a or the like, then reversed by the reversing roller 11j and temporarily stored in the intermediate tray 11g. After the forming process is repeated, the sheets are stacked on the sheet discharge tray 11c.

On the other hand, the transfer drum 5a, from which the transfer-processed recording material P of four colors of yellow, cyan, magenta, and black is separated from the outer peripheral surface, scatters powder or the like onto the recording material carrying sheet 5g. Fur brush 13a, backup brush 13b, and rotatable oil, which face each other via the recording material carrying sheet 5g, in order to prevent the ink from adhering to the recording material P on which an image is to be formed next. Removal roller 14a and backup brush 14b
The cleaning is performed by the fur brush 13a and the like before the image forming process is started, after the image forming process is completed, and also when a paper jam occurs.

Next, the fixing device 10 provided in the printer section II will be described with reference to FIG. FIG.
3 is a schematic diagram showing a schematic configuration of the fixing device 10;
2A is a schematic cross-sectional view illustrating a schematic configuration of the fixing device 10, while FIG. 2B is a schematic cross-sectional view of a fixing roller 10 a provided in the fixing device 10.

The fixing device 10 includes a cylindrical or substantially cylindrical rotatable fixing roller 10a, and a columnar or substantially columnar rotatable pressure roller 10b.

The fixing roller 10 provided in the fixing device 10
a is formed on the outer peripheral surface of a cylindrical or substantially cylindrical rotatable metal core 31 mainly composed of iron and having a thickness of 0.7 mm, and a layer mainly composed of silicone rubber having a thickness of 1.2 mm. The elastic layer 32 is covered with the fixing roller 10.
The outer diameter of a is set to 40 mm.

In the hollow portion of the fixing roller 10a, halogen heaters 37 having different light distributions as heating means are arranged along the axial direction of the fixing roller 10a, and a thermistor as a temperature detecting sensor is provided on the outer peripheral surface of the fixing roller 10a. Temperature sensing sensor 38 (hereinafter abbreviated as thermistor 39)
A thermistor temperature sensing sensor 39 (hereinafter, abbreviated as the thermistor 39), which is a temperature detecting sensor, is in contact with the outer peripheral surface of one end of the core metal 31 in the axial direction of the core metal 31. And the fixing device 1
0, the switching mechanism 40 disposed outside the thermistor 3
The switch means (not shown) is switched to either supply of electric power to the halogen heater 37 from a commercial power supply (not shown) outside the apparatus or disconnection of the halogen heater 37 from the commercial power supply according to the detected values of 8 and 39. With the ON / OFF control, the temperature of the fixing roller 10a is raised to and maintained at the target temperature of 190 ° C.

In this embodiment, the fixing roller 1
Although the target temperature of 0a is set to 190 ° C., it goes without saying that the target temperature is not limited to this value.

In the present embodiment, the halogen heater 37 disposed in the hollow portion of the fixing roller 10a has a power value of 800 W and is uniform or substantially uniform along the axial direction of the fixing roller 10a. The light distribution is set to be different.

On the other hand, the pressing roller 10b provided in the fixing device 10 has a cylindrical or substantially cylindrical core metal 34 mainly composed of iron, and has a layer thickness of 5 mm mainly composed of silicone rubber. The outer diameter of the pressure roller 10b is set to 30 mm.

The pressure roller 10b is adapted to be pressed to the fixing roller 10a at a specified total pressure value by a pressure mechanism (not shown) provided in the main body of the copying machine. Are driven to rotate at a specified peripheral speed by a driving device (not shown) provided in the control unit.

Therefore, in the fixing device 10, the fixing roller 10 a and the pressing roller 1
When the recording material P carrying the unfixed image passes through the nip portion N formed between the non-fixed image and the non-fixed image, the unfixed image is softened and melted by the heating of the halogen heater 37 and is pressed by the pressing. The recording material P is melted by the pressure, so that an image corresponding to the image information of the document D is recorded on the recording material P.

In this embodiment, the fixing roller 10a
The temperature control device for controlling the temperature of the thermistor 38,
39, and a switching mechanism 40, so that the halogen heater 37 is turned on / off according to the flowchart shown in FIG.
By performing FF control, the target temperature 1 of the fixing roller 10a
The temperature is maintained at 90 ° C. In addition, FIG.
9 is a flowchart showing an ON / OFF control process of the halogen heater 37 during a process of maintaining the fixing roller 10a at a target temperature of 190 ° C.

Next, the fixing roller 10 according to the present embodiment will be described.
The ON / OFF control process of the halogen heater 37 during the process of maintaining the target temperature a at the target temperature of 190 ° C. will be described with reference to FIG.

First, when a power source (not shown) provided in the main body of the copying machine is pressed by a user or the like (step S100), various devices provided in the main body are started up. Then, the activated switch means is switched to the energization from the commercial power supply to the halogen heater 37, and the heating of the fixing roller 10a by the halogen heater 37 is started (step S101).

Next, when the detected temperature Ta of the thermistor 38 exceeds the target temperature Ta0, or almost simultaneously (step S102), the detected temperature Tb of the thermistor 39 when the detected temperature Ta reaches the target temperature Ta0 is calculated.
(Step S1).
03), switch means using a commercial power supply and a halogen heater 37
The heating of the fixing roller 10a by the halogen heater 37 is stopped (step S104).

Next, it is determined whether the detected temperature Ta of the thermistor 38 is higher or lower than the target temperature Ta0 (step S105). While the detected temperature Ta is higher than the target temperature Ta0, the halogen heater 37 is detected. O
Continue FF.

On the other hand, it is determined whether or not the detected temperature Tb of the thermistor 39 is higher or lower than the target temperature Tb0 at the same time or almost simultaneously when the detected temperature Ta of the thermistor 38 is lower than the target temperature Ta0 (step S10).
6) While the detected temperature Tb is higher than the target temperature Tb0, the halogen heater 37 is kept turned off (Step S).
107) On the other hand, when the detected temperature Tb falls below the target temperature Tb0, the halogen heater 37 is turned on at the same time or almost simultaneously, and the process returns to step S105.

Therefore, the inventor of the present invention turned on / off the present embodiment to confirm the effect obtained by the present embodiment.
When the fixing roller 10a is maintained at the target temperature by the F control, and when the fixing roller 10a is turned on in accordance with the temperature detected by the thermistor 38.
When the fixing roller 10a was maintained at the target temperature by the / OFF control (corresponding to the conventional ON / OFF control process), the maximum temperature and the minimum temperature of the fixing roller 10a were compared and measured. Table 1 below
Was obtained.

[0088]

[Table 1]

Therefore, in this embodiment, the detected temperature Ta of the thermistor 38 and the detected temperature Tb of the thermistor 39
In response to the above, the switch means switches to either one of energization and cutoff from the commercial power supply to the halogen heater 37 to raise and maintain the temperature of the fixing roller 10a to the target temperature Ta0. Ta0
The temperature ripple, which is the difference between the maximum value and the minimum value of the temperature of the fixing roller 10a during the maintenance process, can be reduced, and the fixing property of the fixing device 10 can be stably maintained. Image formation according to the image information of D can be provided to a user or the like in a favorable state.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIG.

FIG. 4 is a schematic diagram showing a schematic configuration of a fixing device 50 (hereinafter, referred to as a fixing device 50) which is a preferred example of the fixing device of the present embodiment. It is a schematic cross-sectional view showing a schematic configuration of,
(B) shows a fixing roller 10 a provided in the fixing device 50.
FIG. 3 is a schematic sectional view of FIG.

In FIG. 4, parts common to the fixing device 10 are given the same reference numerals as in FIG.

The fixing device 50 has a cylindrical or substantially cylindrical rotatable fixing roller 10a and a columnar or substantially columnar rotatable pressure roller 10b.

The fixing roller 10 provided in the fixing device 510
Halogen heaters 37 having different light distributions as heating means are arranged along the axial direction of the fixing roller 10a in the hollow portion of a, and a thermistor 39 as a temperature detection sensor abuts on the outer peripheral surface of the fixing roller 10a. Arranged, metal core 3
A thermistor temperature sensing sensor 51 (hereinafter, abbreviated as the thermistor 51), which is a temperature sensing sensor, is disposed in contact with the inner peripheral surface of one end of the cored bar 31 in the axial direction of the shaft 1. A switching mechanism 40 disposed outside the device 50 supplies power to the halogen heater 37 from a commercial power supply (not shown) outside the apparatus and switches between the commercial power supply and the halogen heater 37 according to the detection values of the thermistors 38 and 51. O means to switch the switch means (not shown) to one of the interruptions
By performing the N / OFF control in accordance with the flowchart shown in FIG. 3, the temperature of the fixing roller 10a is raised to and maintained at the target temperature of 190 ° C.

In this embodiment, the fixing roller 1
Although the target temperature of 0a is set to 190 ° C., it goes without saying that the target temperature is not limited to this value.

Therefore, the inventor of the present invention turned on / off the present embodiment to confirm the effect obtained by the present embodiment.
When the fixing roller 10a is maintained at the target temperature by the F control, and when the fixing roller 10a is turned on in accordance with the temperature detected by the thermistor 38.
When the fixing roller 10a was maintained at the target temperature by the / OFF control (corresponding to the conventional ON / OFF control process), the maximum temperature and the minimum temperature of the fixing roller 10a were compared and measured. Table 2 below
Was obtained.

[0097]

[Table 2]

Therefore, in this embodiment, the same effects as those of the first embodiment can be obtained, and the thermistor 51 can be used.
Are arranged in contact with the inner peripheral surface of one end of the cored bar 31, so that the responsiveness of temperature detection with respect to the heating of the fixing roller 10a by the halogen heater 37 can be further improved.

(Third Embodiment) Next, a third embodiment of the present invention will be described with reference to FIG.

FIG. 5 is a schematic diagram showing a schematic configuration of a fixing device 60 (hereinafter, referred to as a fixing device 60) which is a preferred example of the fixing device of the present embodiment. It is a schematic cross-sectional view showing a schematic configuration of,
(B) shows a fixing roller 10 a provided in the fixing device 60.
FIG. 3 is a schematic sectional view of FIG.

In FIG. 5, the common parts with the fixing device 10 are given the same reference numerals as those in FIG.

The fixing device 60 includes a cylindrical or substantially cylindrical rotatable fixing roller 10a, and a cylindrical or substantially cylindrical rotatable pressure roller 10b.

In the present embodiment, a thermistor temperature sensing sensor 61 (hereinafter, thermistor 6) which is a temperature sensing sensor is used.
Abbreviated as 1. ) Is disposed close to the outer peripheral surface of the fixing roller 10a, and the switching mechanism 40
The switch means (not shown) is switched to either energization from the commercial power supply (not shown) to the halogen heater 37 or disconnection from the commercial power supply to the halogen heater 37 in accordance with the detected values 9 and 61. The ON / OFF control is performed in accordance with the flowchart shown in FIG. 3 to raise and maintain the fixing roller 10a at the target temperature of 190 ° C.

In this embodiment, the fixing roller 1
Although the target temperature of 0a is set to 190 ° C., it goes without saying that the target temperature is not limited to this value.

The inventor of the present invention turned on / off the present embodiment in order to confirm the effect obtained by the present embodiment.
When the fixing roller 10a is maintained at the target temperature by the F control, and when the fixing roller 10a is turned on in accordance with the temperature detected by the thermistor 38.
When the fixing roller 10a was maintained at the target temperature by the / OFF control (corresponding to the conventional ON / OFF control process), the maximum temperature and the minimum temperature of the fixing roller 10a were compared and measured. Table 3 below
Was obtained.

[0106]

[Table 3] Therefore, in the present embodiment, the same effect as that of the first embodiment can be obtained, and the thermistor 61 is arranged close to the outer peripheral surface of the fixing roller 10a. Abrasion of the fixing roller 10a and the like due to sliding contact with the fixing roller 10a and the like can be prevented beforehand, so that the life of the fixing roller 10a and the like can be maintained for a long time.

In the first to third embodiments, the fixing roller 10a is driven by the rotation of the pressing roller 10b by rotating the pressing roller 10b. However, the fixing roller 10a
, The fixing roller 10a is driven by the rotation of the pressure roller 10b. However, the fixing roller 10a described in any one of the first to third embodiments can be driven. It goes without saying that the effects and advantages of any of the first to third embodiments can be obtained by performing the ON / OFF control.

Further, in the first to third embodiments, a copy machine which performs a series of image forming processes by reading image information of a document D has been described. Even a printer or the like that performs a series of image forming processes according to image information employs the ON / OFF control described in any of the first to third embodiments. As a result, it goes without saying that the effects and advantages of any of the first to third embodiments can be obtained.

[0109]

As described above, according to the first aspect of the present invention, according to the detection value of the first temperature detection means and the detection value of the second temperature detection means, Since the switch means switches between energization and interruption of the heating means from the commercial power supply, the temperature of the fixing roller is raised and maintained at the target temperature. Therefore, the fixing roller is maintained during the process of maintaining the fixing roller at the target temperature. The temperature ripple, which is the difference between the maximum value and the minimum value of the temperature, can be reduced.

Further, according to the second invention of the present application, each detected value of one or a plurality of temperature detecting sensors arranged in contact with or close to the outer peripheral surface of the fixing roller and the second temperature are detected. The switch means switches between energization and cutoff of the heating means from the commercial power supply according to the detection value of the detection means, thereby raising and maintaining the temperature of the fixing roller at the target temperature. The temperature ripple, which is the difference between the maximum value and the minimum value of the temperature of the fixing roller during the step of maintaining the temperature, can be reduced.Especially, when a plurality of temperature detection sensors are provided, each of the above detection values and the second The temperature distribution of the fixing roller can be grasped in detail by the combination with the detected value of the temperature detecting means.

Further, according to the third invention of the present application,
The switch means switches from the commercial power supply to the heating means in accordance with the detection value of the first temperature detection means and the detection value of the temperature detection sensor disposed in contact with or close to the outer or inner peripheral surface of the cored bar. By switching to either energization or interruption,
Since the temperature of the fixing roller is raised to and maintained at the target temperature, the temperature ripple, which is the difference between the maximum value and the minimum value of the temperature of the fixing roller during the process of maintaining the fixing roller at the target temperature, can be reduced. When the temperature detection sensor is disposed in contact with or close to the inner peripheral surface of the cored bar, the responsiveness of temperature detection to heating of the fixing roller by the heating unit can be further improved.

According to the fourth aspect of the present invention, when the detected value of the first temperature detecting means is equal to or more than the target value of the outer peripheral surface of the fixing roller, the commercial power supply and the heating means are shut off. When the detected value of the first temperature detecting means is equal to or less than the target value of the outer peripheral surface, the commercial power supply is determined according to the comparison between the second temperature detecting body and the target value of the core metal of the fixing roller. Since the temperature of the fixing roller is raised to and maintained at the target temperature by switching the switch means to either energization to the heating means or to cutoff, the temperature of the fixing roller during the process of maintaining the fixing roller at the target temperature is maintained. The temperature ripple, which is the difference between the highest value and the lowest value, can be reduced.

Furthermore, according to the fifth invention of the present application,
Since the target value of the core metal of the fixing roller is determined according to the target value of the outer peripheral surface of the fixing roller, the temperature of the fixing roller can be adjusted according to the peripheral temperature and humidity of the fixing roller.

Further, according to the sixth aspect of the present invention, the switch means switches from the commercial power supply to the heating means in accordance with the detection value of the first temperature detection means and the detection value of the second temperature detection means. By switching to either energization or interruption,
Since the temperature of the rotatable fixing roller provided in the fixing device is raised and maintained at the target temperature, the difference between the maximum value and the minimum value of the fixing roller temperature during the process of maintaining the fixing roller at the target temperature is calculated. By reducing the temperature ripple, it is possible to provide a fixing device that maintains stable fixing performance.

Further, according to the seventh aspect of the present invention, each detected value of one or more temperature detecting sensors arranged in contact with or in close proximity to the outer peripheral surface of the fixing roller and the second temperature are detected. The switch means switches between energization and cutoff from the commercial power supply to the heating means in accordance with the detection value of the detection means, thereby increasing the temperature of the rotatable fixing roller provided in the fixing device to the target temperature and Since the maintenance is performed, a fixing device that maintains stable fixing performance by reducing a temperature ripple, which is a difference between the maximum value and the minimum value of the temperature of the fixing roller during the process of maintaining the fixing roller at the target temperature, is achieved. In particular, when a plurality of temperature detection sensors are provided, the temperature distribution of the fixing roller can be grasped in detail by combining the above detection values and the detection value of the second temperature detection unit. Ah It is possible to provide a fixing device.

Further, according to the eighth invention of the present application,
The switch means switches from the commercial power supply to the heating means in accordance with the detection value of the first temperature detection means and the detection value of the temperature detection sensor disposed in contact with or close to the outer or inner peripheral surface of the cored bar. By switching to either energization or interruption,
Since the temperature of the rotatable fixing roller provided in the fixing device is raised and maintained at the target temperature, the difference between the maximum value and the minimum value of the fixing roller temperature during the process of maintaining the fixing roller at the target temperature is calculated. It is possible to provide a fixing device that maintains stable fixing performance by reducing the temperature ripple, and particularly when the temperature detection sensor is disposed in contact with or close to the inner peripheral surface of the cored bar. Can provide a fixing device in which the responsiveness of temperature detection to the heating of the fixing roller by the heating unit is further improved.

According to the ninth aspect of the present invention, when the detected value of the first temperature detecting means is equal to or more than the target value of the outer peripheral surface of the fixing roller, the commercial power supply and the heating means are shut off. When the detected value of the first temperature detecting means is equal to or less than the target value of the outer peripheral surface, the commercial power supply is determined according to the comparison between the second temperature detecting body and the target value of the core metal of the fixing roller. By switching the switch means to either the energization to the heating means or to the interruption of the heating means, the temperature of the rotatable fixing roller provided in the fixing device is raised and maintained at the target temperature. By reducing the temperature ripple, which is the difference between the maximum value and the minimum value of the temperature of the fixing roller during the maintenance process, it is possible to provide a fixing device that maintains stable fixing performance.

Further, according to the tenth invention of the present application,
Since the target value of the core metal of the fixing roller is determined according to the target value of the outer peripheral surface of the rotatable fixing roller provided in the fixing device, the temperature of the fixing roller is adjusted according to the peripheral temperature and humidity of the fixing roller. Can be provided.

According to the eleventh invention of the present application,
The switch means switches between one of energization and cutoff from the commercial power supply to the heating means according to the detection value of the first temperature detection means and the detection value of the second temperature detection means provided in the temperature control device. In this manner, the temperature of the rotatable fixing roller provided in the fixing device is raised and maintained at the target temperature, and the difference between the maximum value and the minimum value of the fixing roller temperature during the process of maintaining the fixing roller at the target temperature It is possible to provide an image forming apparatus having a fixing device in which the temperature ripple has been reduced, thereby providing a stable image.

According to the twelfth invention of the present application,
Each detected value of one or a plurality of temperature detection sensors provided in the temperature control device so as to be in contact with or close to the outer peripheral surface of the rotatable fixing roller provided in the fixing device and the second temperature detection The temperature of the fixing roller is raised and maintained at the target temperature by fixing the temperature of the fixing roller to the target temperature of the fixing roller. Image forming apparatus having a fixing device in which the temperature ripple, which is the difference between the maximum value and the minimum value of the temperature of the fixing roller during the maintenance process, is reduced. In particular, when a plurality of temperature detection sensors are provided, the temperature distribution of the fixing roller can be grasped in detail by combining the above detection values and the detection value of the second temperature detection unit. It is possible to provide an image forming apparatus having that fixing device.

Further, according to the thirteenth invention of the present application, the detection value of the first temperature detecting means provided in the temperature control device and the rotatable fixing roller provided in the fixing device are constituted. The switch means switches between energization and cutoff from the commercial power supply to the heating means in accordance with a detection value of a temperature detection sensor arranged in contact with or close to the outer peripheral surface or the inner peripheral surface of the cored bar. In this manner, the temperature of the rotatable fixing roller provided in the fixing device is raised and maintained at the target temperature, and the difference between the maximum value and the minimum value of the fixing roller temperature during the process of maintaining the fixing roller at the target temperature It is possible to provide an image forming apparatus having a fixing device in which the temperature ripple is reduced, and to provide a stable image. Abut or close to When location can provide an image forming apparatus having a fixing device further improvement in responsiveness of the temperature detection is achieved for heating of the fixing roller of the heating means.

According to a fourteenth aspect of the present invention,
When the detected value of the first temperature detecting means provided in the temperature control device is equal to or more than the target value on the outer peripheral surface of the rotatable fixing roller provided in the fixing device, the commercial power supply and the heating means are shut off. When the detection value of the first temperature detecting means is equal to or less than the target value of the outer peripheral surface, the switch means is switched from the commercial power supply according to the comparison between the second temperature detecting body and the target value of the core metal of the fixing roller. By switching the switch means to either energization or cutoff of the heating means,
Since the temperature of the rotatable fixing roller provided in the fixing device is raised and maintained at the target temperature, the temperature which is the difference between the maximum value and the minimum value of the fixing roller temperature during the process of maintaining the fixing roller at the target temperature is performed. An image forming apparatus having a fixing device with reduced ripple can be provided, and
It is possible to provide a stable image.

Further, according to the fifteenth aspect of the present invention, the target value of the core metal of the fixing roller is determined according to the target value of the outer peripheral surface of the rotatable fixing roller provided in the fixing device. Therefore, it is possible to provide an image forming apparatus having a fixing device capable of adjusting the temperature of the fixing roller according to the ambient temperature and humidity of the fixing roller.

[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.

FIGS. 2A and 2B are schematic diagrams illustrating a schematic configuration of the fixing device illustrated in FIG. 1; FIG. 2A is a schematic cross-sectional view illustrating a schematic configuration of the fixing device; FIG. 3 is a schematic cross-sectional view of a fixing roller provided in the printer.

FIG. 3 is a flowchart showing a halogen heater ON / OFF control process during a process of maintaining the fixing roller at a target temperature of 190 ° C. shown in FIG. 2;

FIG. 4 is a schematic diagram illustrating a schematic configuration of a fixing device according to a second embodiment of the present invention. FIG. 4A is a schematic cross-sectional view illustrating a schematic configuration of the fixing device. Is
FIG. 3 is a schematic sectional view of a fixing roller provided in the fixing device.

5A and 5B are schematic diagrams illustrating a schematic configuration of a fixing device according to a third embodiment of the present invention, and FIG. 5A is a schematic cross-sectional view illustrating a schematic configuration of the fixing device, and FIG. Is
FIG. 3 is a schematic sectional view of a fixing roller provided in the fixing device.

FIG. 6 is a graph showing an example of a change in the temperature detected by a thermistor during a process of maintaining a fixing roller provided in a conventional fixing device at a target temperature.

[Description of Signs] 10 Fixing device 37 Halogen heater (heating means) 38 Thermistor temperature detection sensor (Temperature detection sensor) 39 Thermistor temperature detection sensor (Temperature detection sensor) 40 Switching mechanism 50 Fixing device 51 Thermistor temperature detection sensor ( Temperature detection sensor) 61 Thermistor temperature detection sensor (Temperature detection sensor) 10a Fixing roller 10b Pressure roller P Recording material

Claims (15)

[Claims] 1. A cylindrical or substantially cylindrical rotatable fixing member having an outer peripheral surface formed on a sheet-shaped recording material carrying an unfixed image and conducting heat from a heating unit which generates heat by supplying electricity from a commercial power supply. A temperature control device adapted to control a temperature of a roller, wherein a fixing roller is covered with a coating layer mainly composed of an elastic material on an outer peripheral surface of a cylindrical or substantially cylindrical core. A heating means is disposed in the hollow portion together with the first temperature detecting means for detecting the temperature of the outer peripheral surface of the fixing roller, and a switch means for switching either one of energization from the commercial power supply to the heating means and cutoff. And a second temperature detecting means for detecting the temperature of the cored bar, wherein a detected value of the first temperature detecting means and a detected value of the second temperature detecting means are provided. And switch A temperature control device, wherein the switching means is set to switch between energization and interruption of the heating means from the commercial power supply. 2. The temperature detecting device according to claim 1, wherein the first temperature detecting unit is one or a plurality of temperature detecting sensors that detect the temperature of the outer peripheral surface by being disposed in contact with or close to the outer peripheral surface of the fixing roller. The temperature control device according to claim 1. 3. The temperature detecting device according to claim 2, wherein the second temperature detecting means is a temperature detecting sensor that detects a temperature of the core metal by being disposed in contact with or close to an outer peripheral surface or an inner peripheral surface of the core metal. The temperature control device according to claim 1 or 2. 4. When the detected value of the first temperature detecting means is equal to or more than a target value on the outer peripheral surface of the fixing roller, the switch means is switched to cut off the commercial power supply and the heating means. When the detected value is equal to or less than the target value of the outer peripheral surface, one of the power supply to the heating unit from the commercial power supply and the cutoff is performed according to the comparison between the second temperature detector and the target value of the core metal of the fixing roller. The temperature control device according to any one of claims 1 to 3, wherein the switch means is switched. 5. The fixing device according to claim 1, wherein the target value of the core metal of the fixing roller is set according to the target value of the outer peripheral surface of the fixing roller. Temperature control device. 6. A fixing device for applying a fixing process to a sheet-like recording material carrying an unfixed image by heating a heating means, wherein the fixing device is provided on an outer peripheral surface of a cylindrical or substantially cylindrical core. A rotatable fixing roller covered with a coating layer mainly composed of an elastic material and having a heating means disposed in a hollow portion of the core metal, is pressed against the fixing roller via the recording material. A rotatable pressure roller having a cylindrical or substantially cylindrical shape or a cylindrical or substantially cylindrical shape, wherein the temperature of the fixing roller is controlled by the temperature control device according to claim 1. Fixing device. 7. The temperature detecting device according to claim 1, wherein the first temperature detecting means is one or a plurality of temperature detecting members which detect the temperature of the outer peripheral surface by being disposed in contact with or close to the outer peripheral surface of the fixing roller. The fixing device according to claim 6. 8. The temperature detecting sensor according to claim 1, wherein the second temperature detecting means is a temperature detecting sensor that detects a temperature of the core metal by being disposed in contact with or close to an outer peripheral surface or an inner peripheral surface of the core metal. The fixing device according to claim 6. 9. When the detected value of the first temperature detecting means is equal to or more than the target value of the outer peripheral surface of the fixing roller, the switch means is switched so as to cut off the commercial power supply and the heating means. When the detected value is equal to or less than the target value of the outer peripheral surface, one of the power supply to the heating unit from the commercial power supply and the cutoff is performed according to the comparison between the second temperature detector and the target value of the core metal of the fixing roller. 9. The fixing device according to claim 6, wherein a switch unit is switched. 10. The fixing device according to claim 6, wherein the target value of the core metal of the fixing roller is set so as to be determined according to the target value of the outer peripheral surface of the fixing roller. Fixing device. 11. An image forming apparatus comprising: the temperature control device according to claim 1; and the fixing device according to claim 6. 12. The temperature detecting means according to claim 1, wherein said first temperature detecting means is one or a plurality of temperature detecting bodies which detect the temperature of said outer peripheral surface by being placed in contact with or close to the outer peripheral surface of said fixing roller. The image forming apparatus according to claim 11, wherein: 13. The temperature detecting sensor according to claim 1, wherein the second temperature detecting means is a temperature detecting sensor that detects the temperature of the core metal by being disposed in contact with or close to the outer peripheral surface or the inner peripheral surface of the core metal. An image forming apparatus according to claim 11 or claim 12. 14. When the detected value of the first temperature detecting means is equal to or more than the target value of the outer peripheral surface of the fixing roller, the switch means is switched so as to cut off the commercial power supply and the heating means. When the detected value is equal to or less than the target value of the outer peripheral surface, one of the power supply to the heating unit from the commercial power supply and the cutoff is performed according to the comparison between the second temperature detector and the target value of the core metal of the fixing roller. 14. A switch according to claim 11, wherein the switch is switched.
The image forming apparatus according to claim 1. 15. The fixing roller according to claim 11, wherein the target value of the core metal of the fixing roller is set so as to be determined according to the target value of the outer peripheral surface of the fixing roller. Image forming apparatus.