JP2000206811A - Heat fixing device and image forming device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] In on-demand fixing, a plurality of heating elements cannot be controlled without information on a transfer material. Transfer material detecting means corresponding to various transfer material widths is required, and there is a problem that the apparatus is complicated and the cost is increased. A heating rotator includes a flexible film having a release layer formed on a surface layer, and a plurality of heating rotators each having a different heat generation distribution in a direction orthogonal to the recording material feeding direction, each of which is independently controlled for energization. Heating elements 12a and 12b are provided on a heat-resistant substrate, and a heater 12 fixedly arranged so as to contact the inner peripheral surface of the flexible film is used.
The power supply to each of the heating elements is controlled based on the temperature detection results of a plurality of temperature detection elements 14a and 14b provided at different positions in a direction orthogonal to the recording material feeding direction of the heater. .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat fixing device used for an electrophotographic copying machine, a printer, a recording device, and the like, and an image forming apparatus to which the heat fixing device is applied.

[0002]

2. Description of the Related Art Conventionally, as this kind of heat fixing means,
It employs a contact heating type heat roller fixing method with good thermal efficiency and safety, and an energy saving type film heating method.

[0003] The heat fixing device of the heat roller fixing system basically has a heating roller (fixing roller) as a heating rotating body and an elastic pressure roller as a pressing rotating body pressed against the heating roller. A recording material (transfer material sheet, electrostatic recording paper, electrofax) as a material to be heated in which an unfixed image (toner image) is formed and carried on a pressure contact nip portion (fixing nip portion) of the pair of rollers by rotating a roller. Paper, printing paper, etc.) and passes through the press-contact nip section while pinching and passing, so that the heat from the fixing roller and the pressing force of the press-contact nip section cause the unfixed toner image to be permanently fixed on the recording material surface as a hot-press image. It is to fix it.

Further, a heat fixing device of a film heating system is disclosed in, for example, Japanese Patent Application Laid-Open No. 63-313182,
57878, JP-A-4-44075 to JP-A-4-4083, JP-A-4-204980 to JP-A-4-204984, and the like,
A heat-resistant film (fixing film), which is a rotating body for heating, is brought into close contact with a heating element by a rotating body for pressure (elastic roller) and slid and conveyed, and a heating element (heater) is sandwiched between the fixing film.
A recording material (hereinafter, referred to as a transfer material) carrying an unfixed toner image is introduced into a pressure contact nip formed by the pressure member and the pressing member, and is conveyed together with the fixing film to be applied via the fixing film. The unfixed toner image is fixed as a permanent image on the transfer material by the heat from the heater and the pressing force of the pressure contact nip.

[0005] The heat fixing device of the film heating type is
Since a linear heating element having a low heat capacity and a film having a low heat capacity of a thin film can be used as the heater, power saving and shortening of wait time (quick start property) are possible.

[0006]

In the above-described heat fixing apparatus of the film heating type, since the heat capacity of both the heater and the fixing film is small, the heat in the direction perpendicular to the feeding direction of the transfer material (hereinafter referred to as the longitudinal direction). When the transfer material with poor conductivity and a width smaller than the maximum size is passed, the temperature rise in the non-sheet passing area is likely to be large, and the members holding the heater, the film, the pressure roller, etc. are thermally damaged. In order to prevent this, the throughput (feed interval) of small-sized paper has to be reduced.

Further, when a wide transfer material is passed immediately after the small-size paper is passed, only the non-passage area of the small-size paper has a heater,
Because the temperature of the pressure roller is high, hot offset is likely to occur in this area, and in order to prevent this phenomenon, a pause must be provided before printing large-sized paper after passing small-sized paper. There were also issues.

Further, recently, the number of occasions for printing mails such as envelopes using a laser beam printer has been increasing.
At this time, the address of the destination is printed on the envelope, and the text is printed on plain paper alternately.
Is widespread. In contrast to such alternate sheet feeding, the conventional film heating type heat fixing device has a disadvantage that hot offset occurs on plain sheet after passing the envelope unless the interval between alternate sheet feeding of envelope and plain sheet is widened. Yes, it was necessary to increase the paper feed interval in accordance with the increase in the number of continuous prints of the alternate paper feed. However, control in a case where various print modes are assumed (particularly, the history before the start of the alternate paper feed of the fixing device) becomes complicated. Actually, only the paper feed interval is made constant.

For this reason, the alternate paper feed interval is very long in order to provide a sufficient margin in advance, assuming that the number of continuous print sheets is large. Even in an image forming apparatus capable of printing sheets, in alternate paper feeding, when only one set of envelopes and plain paper is used, only about two sets of throughput per minute can be obtained, and the throughput is extremely reduced.

In order to prevent this phenomenon, there has been proposed an idea that a heating element on a heater is divided into a plurality of heating elements and a heating area is made variable in accordance with the width of a transfer material. At present, it has not been put to practical use yet.

When a transfer material having a small width is passed, the temperature distribution on the ceramic substrate is rapidly increased in a non-sheet passing area immediately outside the sheet passing area. Therefore, in order to cope with various transfer material widths, it is necessary to independently control the energization of several types of heating elements, and a large number of contact electrodes corresponding to the independent heating elements are required. In addition, the number of drive circuits for driving each heating element becomes too large, resulting in high cost and no practical use.

Further, if there is no information about the transfer material width, it is impossible to control the plurality of heating elements, so that a transfer material width detecting means corresponding to various different transfer material widths is required. This leads to increased complexity and cost, and is not practical. Particularly, in recent years, transfer materials other than the standard size have been widely used, and it has become impossible to detect all the transfer material widths.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has been made to reduce the non-sheet-passing temperature rise in on-demand fixing, to improve the throughput at the time of small-size sheet passing, and to optimize the heater control for the transfer material size. It is an object of the present invention to obtain a heat fixing device that can be realized regardless of the above.

Another object of the present invention is to provide an image forming apparatus which performs a high quality image forming operation by a smooth fixing operation by applying the heat fixing device.

[0015]

According to the present invention, there is provided a heat fixing apparatus and an image forming apparatus having the following constitution.

(1) A recording material having an unfixed toner image on its surface is passed through a nip formed by a heating rotator and a pressing rotator, so that the unfixed toner image is transferred onto the recording material surface. In the heat fixing device for performing permanent fixing, the heating rotator includes a flexible film having a release layer formed on a surface layer and heat generation different in a direction perpendicular to the recording material feeding direction, in which power is independently controlled. A plurality of heating elements having a distribution are provided on a heat-resistant substrate and fixedly arranged so as to come into contact with the inner peripheral surface of the flexible film. The heater has a different direction perpendicular to the recording material feeding direction of the heater. A heating and fixing device, characterized in that energization of each of the heating elements is controlled based on temperature detection results of a plurality of temperature detection elements provided at positions.

(2) The flexible film has a thickness of 20 to 1
It is either a cylindrical shape of 00 μm, an endless shape, or a rolled web shape (1).
The fixing device according to claim 1.

(3) The heat fixing apparatus according to (1), wherein the heat-resistant substrate is made of ceramic.

(4) The heating / fixing apparatus according to (1), wherein at the start of the printing operation, the paper feed timing is determined based on the temperature detection results of the plurality of temperature detecting elements and information on the transfer material to be printed.

(5) The heat fixing device according to (1), wherein the energization of each of the heating elements is controlled based on the temperature detection results of the plurality of temperature detection elements, and simultaneously the transfer interval of the transfer material is controlled.

(6) During or before the fixing operation, the energization of each heating element is controlled on the basis of information on the size of the transfer material to be entered next in the fixing operation and the temperature detection results of the plurality of temperature detecting elements. 1) The heat fixing device according to 1).

(7) At least the temperature detecting element provided outside the minimum size paper passing area is in contact with a high heat conductive member provided in contact with the ceramic substrate in the longitudinal direction. 1) The heat fixing device according to 1).

(8) The heat fixing device according to (1), wherein the ceramic substrate is made of A1N.

(9) An image forming apparatus comprising: an image forming means for forming and carrying an unfixed toner image on a recording material; and a heat fixing means for heating and fixing the unfixed toner image formed and carried on the recording material to the recording material. An image forming apparatus, wherein the heat fixing unit is the heat fixing device according to any one of (1) to (8).

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a schematic sectional view showing a film heating type fixing device according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 10 denotes a cylindrical or endless belt-like film which is fitted around a semicircular film guide member (stay) 13 with a margin in the circumferential length. The film 10 is made of a heat-resistant resin such as a polyimide film or a PEEK film having a total thickness of 100 μm or less, preferably 60 μm or less and 20 μm or more, in order to reduce the heat capacity and improve the quick start property. Reference numeral 11 denotes a pressure roller as a pressure rotating body, and a metal core 1 made of iron, aluminum, or the like.
A silicone rubber layer 11b is provided on 1a, and a resin tube layer 11c such as a PFA tube is provided on the silicone rubber layer as a release layer.

By rotating the pressure roller 11, the film 10 is brought into close contact with the surface of the heater 12 in the clockwise direction indicated by an arrow at least during execution of image fixing, and slides on the surface of the heater 12 at a predetermined peripheral speed, ie, not shown. The transfer material P carrying the unfixed toner image T conveyed from the image forming unit side is rotationally driven at substantially the same peripheral speed as the conveyance speed without wrinkles. The heater 12 includes heating elements (resistance heating elements) 12a and 12b as heat sources that generate heat by supplying power.
The temperature rises due to the heat generated in b.

The transfer material P passes through the fixing nip portion during
Heat energy is applied from the heater 12 via the film 10, so that the unfixed toner image T on the transfer material P is heated and melt-fixed, and the transfer material P is separated and discharged from the film 10 after passing through the fixing nip portion. .

The fixing film 10 used in the heat fixing apparatus according to the first embodiment is prepared by applying a polyimide varnish to a cylindrical surface at a predetermined thickness, heating and curing the same, and then applying PF to the surface.
A, PTFE or a mixture thereof is obtained by coating and baking. In the first embodiment, polyimide having a thickness of 50 μm is used as a film substrate, and
A PFA layer of 0 μm is provided.
5φ.

The pressure roller 11 is a core metal 11 made of iron, aluminum or the like.
a, after performing surface roughening treatment such as blasting,
Next, the core metal 11a is inserted into a cylindrical mold, and liquid silicone rubber is injected into the mold and cured by heating. At this time, in order to form a resin tube layer 11c such as a PFA tube as a release layer on the surface layer of the pressure roller, a tube coated with a primer on the inner surface in advance is inserted into the mold, thereby heating and curing the rubber. At the same time, the resin tube layer 11c and the rubber layer 11b
Perform bonding. Pressure roller 1 molded in this way
1 performs secondary vulcanization after demolding. At this time, the core metal diameter of the pressure roller 11 is φ14, the thickness of the rubber layer is 4 mm,
The thickness of the tube layer is 50 μm, and a pressure roller having an outer diameter of about φ22 is used.

The heater 12 serving as a heater for heating includes A12
03 is printed on the substrate with a thick film of Ag / Pd paste in the pattern shown in FIG.
12b is formed, and a glass coating layer having a thickness of 50 to 60 μm is provided thereon. On the other hand, the heating element 12
A chip-shaped thermistor 14a is formed on the substrate on the side opposite to the surface on which the a and 12b are formed by thick-film printing in a region where the heating elements 12a and 12b are both present (in a region where the minimum size width transfer material passes). The temperature of the heater substrate is monitored by bonding and fixing on the formed electrode pattern.
A thermistor 14b is also provided at a position near the end of. The thermistor 14b is fixed to the substrate at a predetermined pressure by a pressing means such as a spring (not shown) in order to detect a temperature exceeding the heat resistant temperature of the adhesive.

With such a configuration, even if accurate transfer material width information is not provided, by controlling the energization of the heating elements 12a and 12b based on the temperature information of the thermistors 14a and 14b, excessive non-sheet passing temperature rise It is possible to maintain the optimum fixing property while preventing the occurrence of the problem.

In the first embodiment, the heating element 1
A sensor is provided slightly outside the width of 2b, and a heating element to be energized in accordance with a signal from the sensor is selected. Specifically, the maximum size width of the transfer material is set to letter (216 mm), and the transfer material of A5 size (148 mm) or less
2b, the fixing operation is performed by controlling the temperature, and the transfer material P wider than the A5 size is transferred to the thermistor 14b.
a, 14b, based on the temperature detection results.
2b is controlled.

The operation and effect of the present invention will be described below based on specific examples.

This heat fixing device is applied to a laser beam printer of 16 sheets per minute (A4 size longitudinal feed),
The width of each of 2a and 12b is 5 mm, and the width of the heater substrate is 14 m.
m, the length of the heating element 12a is 222 mm, the length of the heating element 12b is 154 mm, and the thermistor 14a has a heating element position 12a, a heating element position 12a, within the minimum size transfer material passing area corresponding to the central portion of the transfer material passing area. The thermistor 14b is provided in the heating element region 12b (in the first embodiment, the transfer material is transported with reference to the center), and the thermistor 14b is disposed outside the B5 size width at a position 10 mm from the end of the heating element 12a. .

In such a heating and fixing apparatus, the transfer material having an A4 size width (210 mm) or more has a throughput of 16 sheets per minute, and the heater temperature of the thermistor portion is 190 ° C. by the thermistor 14a provided on the heater substrate. As described above, by controlling the energization of the heating element 12a by the control circuit 21, it was possible to obtain a sufficient fixing property.

On the other hand, the transfer material having an A5 size width or less is 1 / min.
To obtain a throughput of 0 sheets by controlling the energization of the heating element 12b by the control circuit 22 so that the heater temperature of the thermistor section becomes 190 ° C. by the thermistor 14a in the same manner as described above while securing sufficient fixing property. Was completed.

Here, the throughput of the transfer material of A5 width or less is reduced by assuming that the transfer material having a width smaller than that of A5 size such as an envelope is passed. The throughput is reduced to prevent thermal damage to the heater support member, the fixing film, the pressure roller, and the like due to the temperature. Also, it is wider than A5 size width and B5 size width (1
For a transfer material of 82 mm) or less, the energization of the heating elements 12a and 12b is controlled by the following algorithm, and the maximum throughput can be obtained while maintaining the desired fixing property.

When the size of the transfer material is determined to be equal to or larger than the A5 size by a sensor (not shown) provided in the main body conveyance path, as shown in the flowchart of FIG. In the first embodiment, the energization control is performed so that the heater temperature Ta of the thermistor 14a is maintained at 190 ° C. (S2, S3). In this state, the fixing operation of the transfer material having the A5 size width or more is performed. At this time, the temperature Tb of the thermistor 14b is simultaneously monitored, and the temperature Tb is set to the specified temperature T1 (210 ° C. in the first embodiment).
(S4, S5, S6), the heating elements 12a, 1
Thermistor 14 is set while setting the energizing ratio of 2b to 10: 1.
The energization control is performed so that the heater temperature of part a is maintained at 190 ° C. (Electrification is performed to the heating elements 12 a and 12 b by wave number or phase control so as to maintain a predetermined energization ratio between 0.5 and 1.0 sec. I do).

Here, when the heating element 12b is energized, there is a concern about the fixability of the toner on the transfer material outside the heating element 12b. When the temperature rises outside the paper passing area, the heat of that part slightly flows into the transfer material passage area, so that fixing failure does not occur.

During this operation, the thermistor 1
When the heater temperature Tb detected at the portion 4b falls below the specified temperature T1, the energization ratio of the heating elements 12a and 12b is again 10:
0, and the temperature control is performed only by the heating element 12a.

As a result of this control, the temperature of the A4 size and the letter size, in which the thermistor 14b is provided in the paper passing area, is always controlled by energizing only the heating element 12a. When the above control is being performed, the thermistor 14
When the heater temperature Tb of the portion b exceeds the specified temperature T2 (220 ° C.) (S7, S8), the energization ratio of the heating elements 12a and 12b is set to 10: 2, and the heater temperature Ta of the thermistor 14a is maintained at 190 ° C. The energization control is performed so that it is dripped.

Further, when the above control is being performed, the heater temperature Tb of the thermistor 14b is adjusted to the specified temperature T3 (230
° C) (S9, S10), the heating elements 12a, 12
The energization ratio of b is set to 10: 3, and energization is controlled so that the heater temperature Ta of the thermistor 14a is maintained at 190 ° C.

When the heater temperature Tb of the thermistor 14b continues to rise and exceeds the specified temperature T4 (240 ° C.) even in the above control mode, the heating elements 12a, 1
It is determined that it is impossible to suppress the non-sheet-passing temperature rise while maintaining the fixing property (particularly, the outer portion of the heating element 12b) only by switching the energization ratio of 2b, and temporarily interrupts the continuous feeding operation of the transfer material P. (S11).

Thereafter, when the temperature Tb of the thermistor 14b drops below a predetermined temperature (220 ° C. in the first embodiment), the printing operation is started again (S12).
By providing a plurality of tables for switching the energization ratio to the heating elements 12a and 12b in accordance with the temperature detected by the thermistor 14b, even if there is no accurate transfer material width information, the paper throughput can be maintained while maintaining a predetermined throughput. Can be performed.

In the first embodiment, the following control is performed on the assumption that a paper feed port or a transfer material size is changed when the next printing operation is performed. First, when the engine receives the print start command, for example, the paper feed port has changed from the previous print operation at the next print operation, and the transfer material size of the changed paper feed port is larger than the transfer material size printed last time. When it is determined that the width is small, the printing operation is immediately performed, and the feeding of the transfer material can be started.

However, when the transfer material size of the changed paper feed port is wider than the transfer material size printed last time,
Alternatively, when it is not clear whether the width is wide or not, as shown in the flowchart of FIG. 4, after the print start command is received, the detection temperatures Ta and Tb of the thermistors 14a and 14b are monitored, and the temperature difference Ta− Tb is a predetermined temperature T5
(30 ° C. in the first embodiment) or less, the transfer material P
(S45, S46), and the predetermined temperature T5
In the above case, the engine unit accepts the print command from the controller in the ready state, but when the detected temperature difference between the thermistors 14a and 14b becomes equal to or lower than the predetermined temperature T5 after receiving the print start command, the transfer material feeding operation. Is started (S46).

At this time, the engine does not perform the paper feeding operation, but the engine starts the print preparation operation, the rotation of the main motor is performed, and the potential stabilizing operation of the photosensitive drum is performed.
The rotation of the polygon mirror of the laser scanner optical system is started (S44). The heat fixing device is a thermistor 14a,
Based on the monitor temperature of the thermistor 14b, the transfer material P having the size of A5 or less is continuously fed,
If the temperature Ta is higher than the temperature Tb of the thermistor 14b, power is supplied to the heating element 12a having a longer width, and the power supply is controlled so that the temperature difference Ta-Tb between the thermistors 14a and 14b becomes equal to or lower than a predetermined temperature (S47, S49) A local fixing failure is prevented by setting the entire heater to a uniform temperature.

On the other hand, when a transfer material larger than A5 size and narrower than A4 size is continuously fed,
The monitor temperature Tb of the thermistor 14b is
Since the temperature is higher than the monitor temperature Ta of the a, the heating element 12b having a short width is energized, and the thermistors 14a, 14b
Is controlled so that the temperature difference Ta−Tb becomes equal to or lower than a predetermined temperature, and the entire heater has a uniform temperature to prevent hot offset.

Here, the heating element 12a or the heating element 12b is energized by rotating the fixing film while the engine is rotating. At this time, if the heating and fixing device is cold, The high viscosity of the grease interposed between the heater and the fixing film prevents the rotation of the fixing film from slipping and damaging the surface of the fixing film. This is to improve the fixability during printing.

When the detected temperature Tb of the thermistor 14b is equal to or higher than the specified temperature T4, the engine of the image forming apparatus temporarily enters the standby state as described in the above-described control operation, and does not receive a print command from the controller. (S42).

Next, when the temperature Tb of the thermistor 14b becomes lower than the specified temperature T2, the engine unit becomes ready and receives a print command from the controller.
The same energization control as described above is performed (S43, S44), and when the temperature Tb of the thermistor 14b becomes 210 ° C. or less, the sheet feeding and image forming operations are performed (S46), and according to the width of the transfer material conveyed at the same time. The heating element to be energized is determined in the same manner as described above (return to S1 in FIG. 3).

When the print command is sent to the image forming apparatus, the above control is performed when the size of the transfer material in the cassette is changed, for example, even if the paper feed port is the same. Also, in the case of paper feeding from a paper feeding port whose transfer material size is unknown, such as paper feeding from a multi-purpose tray, after the continuous printing from the multi-purpose tray is completed, when the next printing operation is performed, the next printing operation is performed. The same control is performed irrespective of the print sheet feeding port and the transfer material size. As a result, when a wide transfer material is passed immediately after a narrow transfer material is passed, printing without a hot offset or a local fixing failure is performed without making a user wait longer than necessary. It is also possible.

By performing the above-described temperature control, for example, in the case where the transfer material width is 170 mm in an irregular size, in the first embodiment, even if the paper is continuously passed at a throughput of 16 sheets per minute, the temperature of the thermistor 14b is reduced. The heater temperature Tb is 23
The temperature was around 0 ° C., and the fixing property was also at a sufficient level.

On the other hand, if the transfer material is passed at a throughput of 16 sheets per minute and the power supply is controlled only by the heating element 12a, the heater temperature Tb of the thermistor 14b exceeds 240 ° C. If you have to use a resin with high heat resistance, it will increase the cost, or if you immediately pass a wide transfer material such as A4 size, letter size, etc.
Inconveniences such as a severe hot offset occurring in a portion where the temperature of non-sheet passing is large are generated.

In order to prevent such inconvenience, a detecting means for detecting the size of the transfer material more finely in the transport path is added, and the throughput is reduced when the transfer material having a predetermined width is passed. Although it is necessary, in addition to the disadvantage that the throughput is reduced, the cost of adding a transfer material width detecting unit is increased.

However, as described above, a plurality of independently driven heating elements 12a and 12b are provided on the heater 12, and these are heated by a plurality of temperature sensing elements provided at different positions in the longitudinal direction on the heater 12. By controlling the energization ratio, the fixing property can be maintained, the throughput can be maintained regardless of the transfer material width, the required transfer material width detecting means is minimized, and the transfer material other than the standard size can be easily applied to the transfer material. A heat fixing device that can be provided can be provided.

Further, even if the size of the transfer material printed last time is unknown, the feed timing of the next print is determined by the temperature information of the temperature detecting element in the non-sheet passing area with respect to the minimum size when starting the next print. By determining an image forming operation such as delaying or leaving it as it is, an image forming apparatus that has various paper feed ports and prints various transfer material sizes does not cause hot offset and the paper feed delay time It can be minimized.

Embodiment 2 In the second embodiment, two heating elements 12a, 12a, and 12b are provided in accordance with the temperature detection result of the thermistor 14b provided at the end in the first embodiment.
In addition to controlling the energization ratio of 12b, the feeding interval of the transfer material is made variable, which will be specifically described below.

The heat fixing device according to the second embodiment is applied to a laser beam printer of 16 sheets per minute (A4 size longitudinal feed), and the width of the heating elements 12a and 12b is 5 mm each.
The width of the heater substrate is 14 mm, and the length of the heating element 12a is 2 mm.
22 mm, the length of the heating element 12b is 154 mm, and the thermistor 14a corresponds to the center of the transfer material passing area, and within the minimum size transfer material passing area, within the heating area of the heating elements 12a and 12b (this embodiment). In the second embodiment, the transfer material is transported with reference to the center.

With such a heating and fixing apparatus, the transfer material having an A4 size width (210 mm) or more has a throughput of 16 sheets per minute, and the heater temperature of the thermistor portion is 190 ° C. by the thermistor 14 a provided on the heater substrate. As described above, by controlling the energization of the heating element 12 a by the control circuit 21, it was possible to obtain sufficient fixing performance.

On the other hand, the transfer material having an A5 size width or less has a throughput of 10 sheets per minute in the same manner as described above.
Thus, by controlling the energization of the heating element 12b by the control circuit 22 so that the heater temperature of the thermistor portion becomes 190 ° C., it was possible to obtain a sufficient fixing property.

The reason why the throughput of the transfer material having the A5 width or less is reduced is that the transfer material having a width smaller than that of the A5 size such as an envelope is passed. The temperature reduces the throughput in order not to cause thermal damage to the heater support member, the fixing film, the pressure roller, and the like. For a transfer material wider than the A5 size width and less than the B5 size width (182 mm), the energization of the heating elements 12a and 12b is controlled by the following algorithm, and the maximum throughput is obtained while maintaining the desired fixing property. It becomes possible.

When the size of the transfer material is determined to be equal to or larger than the A5 size by a sensor (not shown) provided in the main body transport path, first, as shown in the flowchart of FIG. In the second embodiment, energization control is performed so as to maintain the heater temperature of the thermistor 14a at 190 ° C. (S2, S3). In this state, the fixing operation of the transfer material having the A5 size width or more is performed. At this time, the temperature of the thermistor 14b is simultaneously monitored, and when the temperature exceeds the specified temperature T1 (210 ° C. in the second embodiment), The energization control is performed such that the heater temperature of the thermistor 14a is maintained at 190 ° C. while the energization ratio of the heating elements 12a and 12b is set to 10: 1 (S5, S6).

Here, when the heating element 12b is energized, there is a concern about the fixability of the toner on the transfer material outside the heating element 12b. When the temperature rises outside the paper passing area, the heat of that part slightly flows into the transfer material passage area, so that fixing failure does not occur.

During this operation, the thermistor 1
When the heater temperature Tb detected in the portion 4b falls below T1,
The energization ratio of the heating elements 12a and 12b is set to 10: 0 again, and the temperature control is performed only by the heating element 12a. Further, if the heater temperature Tb of the thermistor 14b exceeds the specified temperature T2 (220 ° C.) during the above control, the energization ratio of the heating elements 12a and 12b is set to 10: 2, and the position of the thermistor 14a is determined. The energization is controlled so that the heater temperature Ta is maintained at 190 ° C. (S7, S8). At this time, the feeding interval of the transfer material during the continuous feeding is controlled to be 14 sheets per minute.

Further, when the above control is being performed, the heater temperature Tb at the position of the thermistor 14b is set to the specified temperature T3.
When the temperature exceeds (230 ° C.), the energization ratio of the heating elements 12a and 12b is set to 10: 3, and energization control is performed so that the heater temperature Ta at the position of the thermistor 14a is maintained at 190 ° C.
At this time, the feeding interval of the transfer material during continuous feeding is controlled to be 12 sheets per minute (S9, S10).

When the heater temperature Tb of the thermistor 14b continues to rise even after entering the above control mode and exceeds the specified temperature T4 (240 ° C.), the heating elements 12a, 12
It is determined that it is impossible to suppress the non-sheet-passing temperature increase while maintaining the fixing property (particularly the outer portion of the heating element 12b) only by switching the energization ratio of b, and temporarily suspends the continuous feeding operation of the transfer material. (S11).

As described above, a plurality of tables for switching the energization ratio to the heating elements 12a and 12b in accordance with the detected temperature Tb of the thermistor 14b are provided, and the throughput is also switched at the same time, so that good fixing can be achieved without accurate transfer material width information. It is possible to carry out continuous paper passing without causing excessive temperature rise in non-paper passing while maintaining the property.

By performing the temperature control as described above, for example, when the transfer material width is 170 mm and the paper thickness is 300 mm
Even when a very thick transfer material such as μm is passed, if the sheet is continuously passed at a throughput of 16 sheets per minute, the heater temperature at the thermistor 14b is about 30 sheets and 240
Exceeds ° C. As a result, in the control method according to the first embodiment, the printer is stopped and a problem may occur. However, as in the second embodiment, when the same thick paper is passed as described above by changing the throughput in accordance with the temperature detection result of the thermistor 14b, 100 or more continuous papers can be passed. .

In the second embodiment, as in the first embodiment, when the paper feed port is changed at the time of the next printing after the end of the continuous printing, the thermistor 14a,
The printing operation is determined based on the temperature detection result of 14b.

A control method for alternately feeding different transfer material sizes will be described below. In this example, plain paper (letter size: width 216 mm) and envelope (Com10:
A control method in the case of alternately feeding paper (width 104.8 mm) will be described with reference to the flowchart of FIG. First
When printing the plain paper on the page, since the transfer material width is larger than the A5 size as described above, only the heating element 12a is energized, and the temperature Ta of the thermistor 14a is set to a predetermined temperature (this second embodiment).
Is controlled to keep at 190 ° C.) (S63, S63).
1). Then, the envelopes are fed. At this time, if it is known that the next print is plain paper, the thermistors 14a and 14b are each set to a predetermined temperature (even if the width of the envelopes is smaller than A5 size). (In both embodiments, 190 ° C)
The energization of both the heating elements 12a and 12b is controlled so as to satisfy (S64 to S74).

More specifically, when the temperature Tb detected by the thermistor 14b falls below 180 ° C., the heating element 12a is energized to control the position of the thermistor 14a to be maintained at 190 ° C. (S70). To S73). In this case, the temperature at the position of the thermistor 14b rises due to the non-sheet-passing temperature in the middle of the envelope passing, and when the temperature exceeds 200 ° C, the heating element 12b is energized next, and the position of the thermistor 14a is 190 ° C. (S70 to S7)
4).

As described above, the temperature distribution in the ceramic substrate of the heater 12 is maintained substantially uniform by repeating this operation when the envelope is passed. As a result, even if plain paper is fed after the envelope is passed and the fixing operation is started, local fixing failure and occurrence of hot offset can be prevented.

Further, since the throughput of the image forming apparatus is controlled to 16 sheets per minute for plain paper and 10 sheets per minute for envelopes, the feed timing of plain paper is 3.75 seconds. In the case of alternating paper feeding, the envelope after plain paper is fed when 3.75 seconds elapse after plain paper feeding, and the plain paper after envelope is fed in envelope feeding. When six seconds have elapsed, the paper feeding operation is performed. As a result, the throughput of the alternate sheet feeding is 6.15 sets when one set of plain paper and envelope is used, and relatively high-speed printing is possible.

In the control method described in the second embodiment, for example, in addition to the alternate paper supply of plain paper and envelopes, the paper supply port is alternately switched, and a narrow transfer material and a wide transfer material are alternately switched. The present invention is also applicable to a case in which the sheet is fed to the printer, or a case in which at least one size of the transfer material is unknown.

As described above, a plurality of independently driven heating elements are provided on the heater substrate, and each of the heating elements is provided by a plurality of thermistors (temperature detecting elements) provided at different positions in the longitudinal direction of the heater substrate. By controlling the paper supply interval at the same time as controlling the energization ratio of the body, the fixing property is maintained, and long-term continuous printing can be performed regardless of the transfer material width and thickness. As a result, the required transfer material width detecting means is minimized, and a heat fixing device that can easily cope with a transfer material having a size other than the standard size can be provided.

Embodiment 3 In the third embodiment, as shown in FIG. 7, a high heat conductive metal plate 71 of Al, copper, iron, or the like is provided on the downstream side in the sheet passing direction on the side opposite to the nip surface (thermistor contact surface side) of the heater substrate. And the thermistor 14a is directly adhered to the ceramic substrate in the area where the transfer material of the minimum size width passes, and the thermistor 1 for the non-sheet passing temperature rise monitor
Reference numeral 4b denotes a high heat conductive metal plate 71 which is in contact with a heat-resistant resin or ceramic plate via a heat-resistant resin or ceramic plate. Is variable.

Hereinafter, the third embodiment will be specifically described. This heat fixing device is applied to a laser beam printer of 16 sheets (A4 size longitudinal feed) per minute,
a and 12b each have a width of 5 mm and a heater substrate width of 14 mm
The length of the heating element 12a is 222 mm,
Is 154 mm, the thermistor 14a corresponds to the center of the transfer material passing area, and within the minimum size transfer material passing area, within the heat generating area of the heating elements 12a and 12b (the third embodiment is based on the central reference). The thermistor 14b is provided in the area outside the B5 size width.
It is arranged at a position 20 mm from the end of 2a. The high thermal conductive metal plate 71 made of Al (thickness 1 mm, width 3 mm)
As shown in FIG. 7, the heater is in contact with the ceramic substrate.

With such a heat-fixing apparatus, the transfer material having an A4 size width (210 mm) or more has a throughput of 16 sheets per minute and the thermistor 14a provided on the heater substrate makes the heater temperature of the thermistor portion 190 ° C. As described above, by controlling the energization of the heating element 12 a by the control circuit 21, it was possible to obtain sufficient fixing performance.

On the other hand, for a transfer material having a B5 size width or less, the energization of the heating elements 12a and 12b is controlled by the following algorithm, and the maximum throughput can be obtained while maintaining the desired fixing property.

In the third embodiment, the transfer material size is determined by a sensor (not shown) provided in the main body conveyance path.
When it is determined that the size is equal to or larger than 5 sizes and when it is determined that the size is equal to or smaller than A5 size, the energization ratio to the heating elements 12a and 12b and the throughput of the transfer material are determined based only on the temperature detection results of the thermistors 14a and 14b.

More specifically, as shown in the flowcharts of FIGS. 8 and 9, when the size of the transfer material is determined to be A5 size or more, the heating element 12a is energized. In the third embodiment, the thermistor is used. Heater temperature Ta at position 14a
Is controlled to maintain the temperature at 190 ° C. (S83,
S84, S812, S813). In this state, the fixing operation of the transfer material is performed. At this time, the temperature Tb of the thermistor 14b is monitored at the same time, and when the temperature exceeds a specified temperature T1 (200 ° C. in the third embodiment), the heating element 12
The energization control is performed so that the heater temperature Ta at the position of the thermistor 14 is maintained at 190 ° C. while the energization ratio of a and 12b is set to 10: 2 (S815, S816).

If the width of the transfer material is wider than the heating element 12b, the heating element 12
Although there is a concern about the fixability of the toner on the transfer material in a portion outside the transfer material b, the heat in the portion becomes high due to the sufficiently short energization time of the heating element 12b and the temperature rise outside the transfer material passing area. There is no occurrence of defective fixing due to the transmission of the conductive metal plate into the transfer material passage area.

During this operation, if the heater temperature Ta detected by the thermistor 14b falls below the specified temperature T1, the energization ratio of the heating elements 12a and 12b is changed again to 10:
0, and the temperature control is performed only by the heating element 12a. If the heater temperature Tb at the position of the thermistor 14b exceeds the specified temperature T2 (210 ° C.) during the above control, the energization ratio of the heating elements 12a and 12b is set to 10: 4, and the position of the thermistor 14a is set. Heater temperature Ta is 19
The energization is controlled so as to be maintained at 0 ° C. (S817, S81
8).

Further, when the above control is being performed, the heater temperature Tb at the position of the thermistor 14b is set to the specified temperature T3.
(220 ° C.), the energization ratio of the heating elements 12a and 12b is set to 10: 8, and at this time, the feeding interval of the transfer material during continuous paper passing is controlled to be 14 sheets per minute ( S81
9, S820).

When the above control is being performed, the heater temperature Tb at the position of the thermistor 14b is set to the specified temperature T3.
When the temperature exceeds (230 ° C.), the energization ratio of the heating elements 12a and 12b is set to 10:10, and energization control is performed so that the heater temperature Ta at the position of the thermistor 14a is maintained at 190 ° C. At this time, the feeding interval of the transfer material during continuous feeding is 1 per minute.
Control is performed so that the number of sheets becomes two (S821, S822).

Then, even when the above control mode is entered, the heater temperature Tb at the position of the thermistor 14b continues to rise,
When the temperature exceeds the specified temperature T4 (240 ° C.), the heating element 12
The energization ratios of a and 12b are set to 10:10, and at this time, the feeding interval of the transfer material during the continuous feeding is controlled to be eight sheets per minute (S821, 823).

Next, when it is determined that the transfer material size is equal to or smaller than the A5 size, power is supplied to the heating element 12b, and in the third embodiment, the heater temperature Ta at the thermistor 14a is maintained at a throughput of 16 sheets / min. The energization control is performed so as to maintain the temperature at 190 ° C. (S83 to S87).

In this state, the fixing operation of the transfer material is performed. At this time, the temperature Tb of the thermistor 14b is monitored at the same time, and the temperature Tb is set to the specified temperature T1 '(third embodiment).
(150 ° C.), it is determined that the transfer material is narrower than the A5 size, and the throughput is reduced to 12 sheets / min (S89, S810). After this, the heater temperature Tb at the position of the thermistor 14b further continues to rise, and
If the temperature exceeds ℃, the throughput is further reduced to 10 sheets / min (S89, S811).

As described above, by bringing the high thermal conductive member into contact with the heater, it is possible not only to suppress the decrease in throughput due to the width of the transfer material, but also to reduce the width of the transfer material even when the transfer material has a smaller width. Since the temperature information corresponding to the transfer material width can be obtained by the thermistor provided at the end, the throughput can be accurately controlled corresponding to a wide range of the transfer material width.

Embodiment 4 The fourth embodiment is different from the first embodiment in that a backside heating type heater 12 in which the backside of the substrate contacts the fixing nip surface is used.
The heating element is made of aluminum nitride (hereinafter, AlN)
Is abbreviated). This AlN substrate has the following advantages mainly over the conventional alumina substrate.

The AlN substrate has a thermal conductivity of 220 (W / m ·
° k) and about 11 times higher than that of the alumina substrate (20 W / m · ° k), and the heat capacity is as small as about 2/3 if the volume is the same. Since uniformity is possible and the thermal shock resistance is about twice as much, even if the heating element is made thinner and used at a high temperature, there are many advantages that the substrate is hardly damaged by rapid heating.

In particular, since the AlN substrate has a thermal conductivity that is about two orders of magnitude higher than that of the glass coat layer, the thickness of the substrate is at least 10 times as thick as the glass coat layer (the substrate thickness is about 0.5 to 0.8 mm). In the fourth embodiment, 0.65 mm
And On the other hand, despite the glass thickness being about 30 to 60 μm), as in Embodiment 4, the heating element 12a, the glass coat layer (not shown) and the thermistor are arranged on the upper surface of the substrate, and The backside heating type AlN heater 12 that contacts the fixing nip surface can be used.

The alumina substrate rises faster than the conventional heater and has high thermal conductivity, so that the entire substrate can be heated uniformly and widely, and high fixing performance can be maintained even when the speed is increased. Further, since the temperature distribution in the longitudinal direction is also easily made uniform, there is an effect of alleviating the excessive temperature rise in the non-sheet passing portion, which is a problem when small size paper is continuously passed.

In the fourth embodiment, as shown in the cross-sectional view of FIG. 10, two types of heating elements, ie, a heating element 12a for a wide transfer material and a heating element 12b for a narrow transfer material, are used as the transfer material width. Is independently controlled according to the current. The heating element formed on the AlN substrate in the pattern shown in FIG. 2 is obtained by printing and baking a thick film of Ag · Pd ぺ, on which a glass coating layer 12c is provided with a thickness of 30 to 50 μm. .

On the other hand, the substrate surface opposite to the heating element forming surface is
By lapping the surface or providing a thin glass coating layer having a thickness of 15 μm or less, the surface is smoothened, and the slidability with the film is improved.

The thermistor 14a is composed of the heating elements 12a and 13b
Are brought into contact with the glass layer on the heating element via an insulating heat-resistant resin or ceramic substrate by a spring pressing means (not shown) in the area where both are present (in the area where the transfer material minimum size width paper passes). One thermistor 14b is arranged in a region outside the A5 size width at a position 20 mm from the end of the heating element 12a, similarly to the thermistor 14a.

In the fourth embodiment, a sensor is provided in the transport path slightly outside the width of the heating element 12b, and a heating element to be energized in accordance with a signal from the sensor is selected.

With such a heating and fixing apparatus, the transfer material having an A4 size width (210 mm) or more has a throughput of 16 sheets per minute, and the heater temperature of the thermistor portion becomes 190 ° C. by the thermistor 14a provided on the heater substrate. As described above, by controlling the energization of the heating element 12 a by the control circuit 21, it was possible to obtain sufficient fixing performance. On the other hand, for a transfer material having a B5 size width or less, the energization of the heating elements 12a and 12b is controlled by the following algorithm, and the maximum throughput can be obtained while maintaining the desired fixing property.

In the fourth embodiment, the size of the transfer material is controlled by a sensor (not shown) provided in the main body conveyance path.
When it is determined that the size is equal to or larger than 5 sizes and when it is determined that the size is equal to or smaller than A5 size, the power supply ratio to the heating elements 12a and 12b and the throughput of the transfer material are determined based only on the temperature detection results of the thermistors 14a and 14b.

More specifically, as shown in the flowcharts of FIGS. 11 and 12, when it is determined that the transfer material size is equal to or larger than the A5 size, the heating element 12a is energized. In the fourth embodiment, the thermistor 14a is used. Control is performed such that the heater temperature Ta of the section is maintained at 190 ° C. (S103, S103).
104, S112, S113, S114). In this state, the fixing operation of the transfer material is performed. At this time, the temperature Tb of the thermistor 14b is simultaneously monitored, and when the temperature Tb exceeds the specified temperature T1 (200 ° C. in the fourth embodiment), the heating element 12a , And 12b, the heater temperature Ta at the thermistor 14a position is 19: 3.
The energization control is performed so as to be maintained at 0 ° C. (S115, S11
6).

If the width of the transfer material is wider than the heating element 12b, the heating element 12b is energized when the heating element 12b is energized.
b, there is a concern about the fixability of the toner on the transfer material in the portion outside the transfer material b. However, since the energization time of the heating element 12b is sufficiently short and the temperature rises outside the transfer material passing area, the heat in that portion is reduced to Al.
By transmitting through the high thermal conductive substrate made of N and flowing into the transfer material passage area, fixing failure does not occur. If the heater temperature Tb detected at the position of the thermistor 14b during this operation falls below the specified temperature T1,
The energization ratio of the heating elements 12a and 12b is set to 10: 0 again, and the temperature control is performed only by the heating element 12a.

When the above control is being performed, the heater temperature Tb at the position of the thermistor 14b is set to the specified temperature T2.
When the temperature exceeds (210 ° C.), the energization ratio of the heating elements 12a and 12b is set to 10: 5, and the energization is controlled so that the heater temperature Ta at the position of the thermistor 14a is maintained at 190 ° C. (S117, S118).

Further, when the above control is being performed, the heater temperature Tb at the position of the thermistor 14b is set to the specified temperature T3.
(220 ° C.), the energization ratio of the heating elements 12a and 12b is set to 10:10, and at this time, the feeding interval of the transfer material during continuous paper feeding is controlled to be 14 sheets per minute ( S1
19, S120).

When the above control is being performed, the heater temperature Tb at the position of the thermistor 14b is set to the specified temperature T3.
When the temperature exceeds (230 ° C.), the energization ratio of the heating elements 12a and 12b is set to 10:10, and energization control is performed so that the heater temperature Ta at the position of the thermistor 14a is maintained at 190 ° C. At this time, the feeding interval of the transfer material during continuous feeding is 1 per minute.
Control is performed so that the number of sheets becomes two (S121, S122).

Then, even when the control mode described above is entered, the heater temperature Tb at the position of the thermistor 14b continues to rise,
When the temperature exceeds the specified temperature T4 (240 ° C.), the heating element 12
The energization ratio of a and 12b is set to 10:10, and at this time, the feeding interval of the transfer material during continuous feeding is controlled to be 10 sheets per minute (S121, S123).

Next, when it is determined that the transfer material size is equal to or smaller than the A5 size, power is supplied to the heating element 12b. In the fourth embodiment, the heater temperature Ta at the thermistor 14a is maintained at a throughput of 16 / min. The energization control is performed so as to maintain the temperature at 190 ° C. (S103, S105, S10
6, S107). In this state, the fixing operation of the transfer material is performed. At this time, the temperature Tb of the thermistor 14b is monitored at the same time, and when the temperature Tb exceeds the specified temperature T1 ′ (150 ° C. in the fourth embodiment), the A5 size It is determined that the transfer material is narrower than the transfer material, and the throughput is 12 sheets /
(S109, S110). After this, the heater temperature Tb at the position of the thermistor 14b is further increased to 160 ° C.
Is exceeded, the throughput is further reduced to 10 sheets / minute (S109, S111).

By bringing the high thermal conductive member into contact with the heater in this manner, it is possible not only to suppress a decrease in the throughput due to the width of the transfer material, but also to reduce the edge when the transfer material having a smaller width is passed. Since the temperature information corresponding to the transfer material width can be obtained by the thermistor provided in the section, the throughput can be accurately controlled corresponding to a wide range of the transfer material width.

Embodiment 5 FIG. FIG. 13 is a block diagram showing an image forming apparatus according to the present invention. In FIG. 13, reference numeral 1 denotes a photosensitive drum on which a photosensitive material such as OPC, amorphous Se, or amorphous Si is formed on a cylindrical substrate such as aluminum or nickel. . The photosensitive drum 1 is driven to rotate in the direction of the arrow, and first, its surface is uniformly charged by a charging roller 2 as a charging device. Next, a laser beam 3 serving as an exposure unit
Is subjected to ON / OFF control exposure in accordance with image information, and an electrostatic latent image is formed on the photosensitive drum 1. This electrostatic latent image is developed by the developing device 4 and visualized. As a developing method, a jumping developing method, a two-component developing method, or the like is used, and in many cases, a combination of image exposure and reversal developing is used. The visualized toner image is transferred from the photosensitive drum 1 to a transfer material P fed and conveyed from a feed port of a cassette or a multi-purpose tray at a predetermined timing by a transfer roller as a transfer device.
The transfer material P holding the toner image is conveyed to the fixing device 6 described in each of the above embodiments, and is heated and pressed at the nip portion of the fixing device 6, so that the toner image is fixed on the transfer material and a permanent image is formed. Become. On the other hand, the transfer residual toner remaining on the photosensitive drum 1 after the transfer is removed from the surface of the photosensitive drum 1 by the cleaning device 7 and used for the next image formation.

[0110]

As described above, according to the present invention,
A flexible film having a release layer formed on the surface layer, and a plurality of heating elements having different heat distributions in directions perpendicular to the recording material feeding direction, each of which is independently controlled to be supplied, are provided on a heat-resistant substrate. Using a heating rotator comprising a heater fixedly arranged to contact the inner peripheral surface of the flexible film,
Since the configuration is such that the energization of each of the heating elements is controlled based on the temperature detection results of a plurality of temperature detection elements provided at different positions in a direction orthogonal to the recording material feed direction of the heater, the width is particularly narrow. By detecting the temperatures of the paper passing area and the non-paper passing area with the plurality of temperature detecting elements when the transfer material is passed, the power supply to the plurality of heating elements is controlled according to the width of the transfer material. This makes it possible to eliminate or minimize the transfer material width detecting means.

Further, since the feeding timing is determined based on a plurality of temperature detecting elements and information on the transfer material to be printed at the start of the printing operation, a large-size transfer material can be transferred immediately after the transfer of a narrow transfer material. This has the effect of effectively preventing phenomena such as hot offset and local fixing failure that occur when paper is passed.

Further, since the power supply to each of the heating elements is controlled based on the temperature detection results of the plurality of temperature detecting elements, and at the same time the paper feed interval of the transfer material is controlled, the need for the transfer material width detecting means is eliminated. In addition to minimizing the number of required heating elements, it is possible to minimize the number of required heating elements as well as minimize the number of required heating elements. There is.

Further, according to the transfer material size information which enters the fixing operation before or during the fixing operation, the energization of each heating element is controlled based on the temperature detection results of the plurality of temperature detecting elements. Therefore, even when transfer materials of different sizes are alternately fed, phenomena such as hot offset and fixing failure can be effectively prevented without significantly lowering the throughput.

Further, at least the temperature detecting element provided outside the minimum size paper passing area is configured to contact the high heat conductive member provided in contact with the ceramic substrate in the longitudinal direction, so that the transfer material is provided. In addition to eliminating or minimizing the width detection means, it is possible to control the power supply to the optimal heating element for various sizes of irregularly shaped transfer materials. The number can be minimized. In addition, since the ceramic substrate is made of AlN, it is possible to obtain a heat fixing device that can obtain the same effect as the above with a simpler structure.

Further, by applying this heat fixing device, it is possible to obtain an image forming device capable of forming a high quality image by a smooth fixing operation.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a heat fixing device according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a heater applied to the heat fixing device.

FIG. 3 is a flowchart for explaining a heater energizing operation.

FIG. 4 is a flowchart illustrating an operation after receiving a print start command.

FIG. 5 is a flowchart illustrating an energizing operation according to a second embodiment of the present invention.

FIG. 6 is a flowchart illustrating an operation after receiving a print start command.

FIGS. 7A and 7B are explanatory views of a heater according to a third embodiment of the present invention, wherein FIG. 7A is a front view and FIG. 7B is a side view.

FIG. 8 is a flowchart illustrating an operation after receiving a print start command.

FIG. 9 is a flowchart illustrating an operation after receiving a print start command.

FIG. 10 is an explanatory diagram of a heater according to a fourth embodiment of the present invention.

FIG. 11 is a flowchart illustrating an operation after receiving a print start command.

FIG. 12 is a flowchart illustrating an operation after receiving a print start command.

FIG. 13 is a schematic configuration diagram illustrating an image forming apparatus according to a fifth embodiment of the present invention.

[Explanation of symbols]

1 photosensitive drum, 2 charging roller, 3 laser beam, 6
Heat fixing device, 10 film, 11 pressure roller, 12
Heater, 12a, 12b Heating element, 14a, 14b
Thermistor.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05B 3/20 328 G03G 21/00 372 F term (Reference) 2H027 DA12 DC02 DC10 EA12 ED17 2H033 AA03 BA25 BA26 BA32 BE03 CA07 CA16 CA17 CA37 3K034 AA02 AA10 BA05 BA17 BB06 BB14 BC01 BC12 BC24 CA32 DA05 DA08 EA03 EA13 HA01 HA10 3K058 AA02 AA34 AA41 AA45 AA65 AA81 AA92 BA18 CA12 CA16 CA23 CA46 CA61 CB14 CB25 CE06 CE03 CE02 CE02 CB42 DA01 EE11 FF01 FF10 GG04 HH02 KK05 MM09

Claims (9)

[Claims] An unfixed toner image is made permanent on the surface of the recording material by passing a recording material having an unfixed toner image on its surface through a nip formed by a heating rotator and a pressing rotator. In the heat fixing device for fixing, the heating rotator includes a flexible film having a release layer formed on a surface layer, and a heat generation distribution different in a direction orthogonal to the recording material feeding direction, in which the energization is independently controlled. A plurality of heating elements provided on a heat-resistant substrate and fixedly arranged to be in contact with the inner peripheral surface of the flexible film, and different positions in a direction orthogonal to a recording material feeding direction of the heater. A heating and fixing device for controlling the energization of each of the heat generating elements based on the temperature detection results of the plurality of temperature detecting elements provided in the fixing device. 2. The flexible film has a thickness of 20 to 100.
2. The heat fixing device according to claim 1, wherein the heat fixing device has a cylindrical shape, an endless shape, or a roll-up web shape having a thickness of μm. 3. The heat fixing device according to claim 1, wherein the heat-resistant substrate is made of ceramic. 4. The heat fixing device according to claim 1, wherein at the start of the printing operation, the sheet feeding timing is determined based on temperature detection results of a plurality of temperature detecting elements and information on a transfer material to be printed. 5. The heat fixing apparatus according to claim 1, wherein the control unit controls the energization of each of the heat generating elements based on the temperature detection results of the plurality of temperature detecting elements, and simultaneously controls the sheet feeding interval of the transfer material. 6. The method according to claim 1, further comprising the step of controlling the energization of each heating element based on information on a size of the transfer material to be transferred to the next fixing operation and a temperature detection result of the plurality of temperature detecting elements during or before the fixing operation. 2. The heat fixing device according to 1. 7. The temperature detecting element provided at least outside the minimum size paper passing area is in contact with a high heat conductive member provided in contact with the ceramic substrate in the longitudinal direction. 2. The heat fixing device according to 1. 8. The heat fixing device according to claim 1, wherein the ceramic substrate is made of A1N. 9. An image forming apparatus comprising: image forming means for forming and carrying an unfixed toner image on a recording material; and heat fixing means for heating and fixing the unfixed toner image formed and carried on the recording material to the recording material. 5. The image forming apparatus according to claim 1, wherein the heat fixing unit is the heat fixing device according to claim 1. 6.