JP3070628B2 - Image heating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a rotating endless film and a deviation control means for controlling the deviation of the film in a direction perpendicular to the moving direction of the film to be within a predetermined range. And an image heating apparatus for heating an image on a recording material by heat from the film side.

[0002]

2. Description of the Related Art An image heating apparatus of the above-described film heating type is known from Japanese Patent Application Laid-Open No. 63-313182, and is an image heating fixing apparatus in an image forming apparatus such as an electrophotographic copying machine, a printer and a facsimile. That is, electrophotography
An image forming process such as an electrostatic recording or a magnetic recording may be directly applied to a surface of a recording material (an electrofax sheet, an electrostatic recording sheet, a transfer material sheet printing paper, etc.) using a toner made of a heat-meltable resin or the like. The present invention can be utilized as an image heating and fixing apparatus for performing a heat fixing process on an unfixed visible image (toner image) formed by an indirect (transfer) method and corresponding to target image information as a fixed image on a recording material carrying the image. Further, for example, it can be used as a device for heating a recording material carrying an image to improve the surface properties such as gloss, or a device for performing a temporary deposition process.

[0003] As for the film heating type fixing device, in comparison with other heat fixing type devices such as a heat roller type, a hot plate type, a flash fixing type and an oven fixing type. Since a linear heating element having a low heat capacity can be used as the heating element, and a thin film having a thickness of, for example, about 40 μm can be used as the heating element, it is possible to shorten a rise time to a predetermined fixing temperature and save power. Since the fixing point and the separation point between the film and the recording material can be set separately, toner offset can be prevented, and other advantages such as solving various drawbacks of other system devices can be solved, which is effective. .

[0004] As described above, an endless type film can be used to rotate and drive the film to be used repeatedly, or an endless roll-wound film can be used by running out. it can.

[0005] In a film heating type heating device using an endless type film, the film moves and moves in the width direction (direction perpendicular to the film rotation direction) during the rotation driving process of the film. Actions are taken to restrict movement.

[0006] In order to control the shift, the ribs and flange members are used to restrict the movement of the film. For example, when the shape of the film-suspending and conveying roller is formed into a crown shape, the film is made of a thin film and is made of a material such as polyimide having low elasticity. In some cases, it is difficult to restrict the shift of the film, and it is difficult to ensure the stable rotation and transport of the film.

In view of the above, a means for detecting a shift position of the film is provided, and when it is detected that the shift to one side in the width direction of the film has reached a predetermined limit position, the shift of the film in the return direction is detected. Activating the means for displacing the film suspension conveyance roller so as to change to the other side in the film width direction, and when it is detected that the shift of the film to the other side in the width direction has reached the predetermined limit position, By providing a film shift control mechanism configured to actuate a means for displacing the film suspension transport roller so as to change the film shift to one side in the film width direction that is the return direction, the rotation drive of the endless film In the process, a shift movement control process is performed in which the shift movement in the film width direction is controlled by reciprocating infinitely within a predetermined range.

[0008]

However, a heating device of the film heating type using an endless film provided with the above-mentioned film shift movement control mechanism also has a film shift control instability due to a temperature factor or durability change. is there.

That is, the above-mentioned film shift control mechanism detects the position of the film shift within a certain range, and reciprocates the film within the range to control the shift of the film. When the speed becomes higher, the frequency of reciprocating motion of the film naturally increases, which causes problems such as damage to the film and generation of wrinkles.

[0010] In addition, when a film detection failure or a driving means for displacing the film-suspending conveyance roller, such as a solenoid, is used, the driving frequency of the solenoid increases, and the solenoid itself may be heated more than necessary.

[0011] These conditions can be optimized in the initial state by adjusting the precision and adjustment of parts.
The above-described film shift speed is an unstable factor because a change in durability or the like is expected.

In particular, unlike the general film (belt) conveyance, since the present apparatus is a heating apparatus, the apparatus is heated up to 150 to 150 ° C.
Since the temperature reaches about 200 ° C., the normal temperature state means that the initial film shift condition changes due to the coefficient of friction of the film transporting means, the surface of the heating element, and the thermal expansion of parts such as the film transport roller. I have to.

In a film heating type heating apparatus, it is also known that a fluorine-based heat-resistant grease is applied to the inner surface of the film as a lubricant because the film is conveyed while sliding with a fixedly supported heating element. However, since this type of grease viscosity has a large temperature dependency, this point is also a factor that makes the conditions near the film unstable.

If the film is always reciprocated in the same area, the wear on the surface of the heating element, the heating element supporting member, and the film transport means may be reduced.

Accordingly, the present invention relates to a film heating type heating apparatus using an endless film, which is provided with the above-described film shift movement control mechanism. An object of the present invention is to improve the reliability of an apparatus by enabling stable film shift control for preventing a film detection error from occurring without causing film damage, wrinkles, and the like even if it occurs.

[0016]

According to the present invention, there is provided an image heating apparatus having the following constitution.

[0017] (1) a rotatable endless film, a deviation control means for deviation of the film in the direction perpendicular to the moving direction of the film is controlled to be within a predetermined range, pressure in contact with the film It includes a member, the, before
An image bearing an image at a contact portion between the film and the pressing member.
In an image heating apparatus for nipping and transporting a recording material and heating an image on the recording material by heat from the film side, the pressing member
Temperature detecting comprises means, image heating apparatus characterized by changing the width of the predetermined range by the shift control means in accordance with the detected temperature from the temperature detection means for detecting the temperature of the.

(2) Endless rotatable film
And filling in a direction orthogonal to the direction of movement of the film.
Deviation control hand that controls the deviation of the system to be within a predetermined range.
And a step on the recording material by heat from the film side.
An image heating apparatus for heating an image of
Temperature detecting means for detecting a temperature, wherein the temperature detecting means
A predetermined range by the deviation control means in accordance with the detected temperature from
An image heating apparatus you and changing the width of the circumference.

(3) A heating element and a circuit that slides on the heating element.
Rollable endless film and transfer of said film
The deviation of the film in the direction perpendicular to the moving direction is within the specified range
Shift control means for performing control so that
The image on the recording material is generated by the heat from the heating element through the film.
In an image heating device for heating an image , the temperature of the heating body is
It has a temperature detecting means for detecting, from the temperature detecting means
The width of a predetermined range by the deviation control means according to the detected temperature
An image heating apparatus characterized by changing the following. (4) A rotatable endless film and the film
The film is leaning in the direction perpendicular to the moving direction of the film.
Deviation control means for controlling so as to fall within a fixed range.
Then, the image on the recording material is added by the heat from the film side.
In an image heating apparatus to be heated, the temperature near both ends of the film in a direction orthogonal to the moving direction of the film is respectively
A temperature detection unit for detecting, and a predetermined range determined by the shift control unit in accordance with a difference between the detected temperatures from the temperature detection unit.
An image heating apparatus you and changing the width.

<Operation> That is, a pressing member, a film,
By detecting the temperature near the heating element or both ends of the film and switching the width of the film shift control range accordingly, even if the shift control of the film becomes unstable due to the heat storage of the device, etc. Even if a change in the speed of the film shift due to a change in the endurance occurs, the reciprocation frequency of the film shift control can be suppressed to a certain range, thereby preventing excessive stress on the film and eliminating the occurrence of wrinkles and the like. . In addition, erroneous detection of the film and temperature rise of the solenoid can be minimized, and the shift of the moving distance reduces the rubbing wear of the same part of the film, the heating element and the heating element supporting material. Can extend the life of the device. It can be implemented without increasing the size and complexity of the mechanism for controlling the movement of the film, and can realize stable conveyance of the film with respect to the image heating apparatus of the film heating type using the endless film, thereby improving the reliability of the apparatus. .

[0021]

【Example】

<First Embodiment> (FIGS. 1 to 12) FIG. 1 is a plan view of an example of a heating device according to the present invention,
FIG. 2 is a side view, and FIG. 3 is a schematic configuration diagram of an example of an image forming apparatus in which the heating device is incorporated as a fixing device.

(A) Configuration of Example of Image Forming Apparatus The image forming apparatus shown in FIG. 3 is an electrophotographic copying machine of a platen reciprocating type, a rotating drum type, and a transfer type. Etc. belong to the public domain and will be described only briefly.

Reference numeral 52 denotes a reciprocating original table glass disposed on the upper plate 51 of the copier housing 50, which is driven to reciprocate in the left and right directions by a drive mechanism (not shown). The original 53 is placed at a predetermined position on the upper surface of the original platen glass 52 with the image surface to be copied facing downward, and is held down by the original pressing plate 54 and set.

The downward image surface of the set original 53 undergoes slit illumination scanning by sequentially passing through the illuminating section 55 during the forward or backward movement of the original table glass 52. Reference numeral 56 denotes an illumination light source.

The downward illumination of the slit illumination light reflected from the original surface is sequentially imaged and exposed on an image forming lens (short focus imaging element array) 57 on the surface of a photosensitive drum 58 which rotates synchronously with the scanning of the original image.

The photosensitive drum 58 is subjected to a uniform charging process, positive or negative, by the discharger 59 and then subjected to the above-mentioned image forming exposure, so that an electrostatic latent image corresponding to the original image is sequentially formed on the peripheral surface of the drum. Is formed.

Next, the photosensitive drum 58 on which the latent image is formed
The surface sequentially passes the position of the developing device 60 and undergoes sequential development of the latent image. The developed image on the surface of the photosensitive drum 58 reaches the position of the transfer discharger 61 by the subsequent rotation of the photosensitive drum.

On the other hand, the transfer material P is fed one by one into the copying machine from the paper supply cassette 62 by the paper supply roller 63, and the leading end of the transfer material P is received at the nip portion of the registration roller pair 64 which is in a rotation stopped state at that time. Has been stopped. Here, the photosensitive drum 58
The rotation of the registration roller pair 64 is started at a predetermined timing synchronized with the rotation of the transfer material P.
Is guided toward the photosensitive drum 58 by a guide member, is introduced into a transfer section between the photosensitive drum 58 and the transfer discharger 61, and the developed image on the surface of the photosensitive drum 58 is sequentially transferred to the transfer material P. You.

The copy material P having received the image transfer is a photosensitive drum 58
The transfer device 6 is sequentially separated from the surface by a separation unit (not shown).
5, the image is introduced into the fixing device 1, and the image is fixed.
It is discharged to 7.

After the image is transferred, the surface of the photosensitive drum 58 is cleaned by a cleaning device 68 and repeatedly used for image formation.

(B) Fixing device 1 In FIGS. 1 and 2, reference numerals 13 and 12 denote a pair of left and right endless film drive rollers and a driven roller which also serves as a tension roller. An endless film stretched between 12 and having a predetermined peripheral speed in the clockwise direction of arrow a by the drive roller 13 being driven to rotate clockwise in the direction of arrow by the drive system including the drive motor 27; It is driven to rotate.

The film 11 is a heat-resistant film having a total thickness of 100 μm, more preferably less than 40 μm. In this embodiment, an endless film having a thickness of about 20 μm such as polyimide, polyetherimide, PES, PFA or the like as a base film and a release layer of PTFE or the like coated on the image contact surface by about 10 μm.

Reference numeral 14 denotes a heating element fixedly disposed (fixed and supported by a fixing device) on the inner surface of the descending film portion of the endless film 11 described above. This heating element is a film 11
Is a low-heat-capacity linear heating element (hereinafter, referred to as a heater) having a length in the direction intersecting the surface movement direction, that is, the film width direction, and generates heat when energized.

RT1 is a first for detecting the temperature of the heater 14.
, And is mounted near the heater 14. As will be described later, the detected temperature information of the first thermistor RT1 is input to the microcomputer 26 (FIG. 7), and the microcomputer 26 receives the information from the thermistor RT1.
A signal is sent to the heater energizing circuit 25 to control the temperature of the heater 14 so that the detected temperature of the heater 14 becomes a predetermined substantially constant.

Reference numeral 15 denotes a pressure roller having a rubber elastic layer having good releasability, such as silicon rubber, and a biasing portion (not shown) sandwiching the film portion on the lower side of the endless film 11 between the heater 14 and the pressure roller. By means, for example, total pressure 4-5kg
, And rotates in the film moving direction in the forward direction at the same peripheral speed as the film speed as the film moves.

Reference numeral 24 denotes a thermistor unit pressed against the surface of the pressure roller 15, and a second thermistor RT is attached to the sponge.
2 and the surface is covered with Kapton tape, and the temperature of the pressure roller 15 is detected. The detected temperature information about the pressure roller 15 by the second thermistor RT2 is also input to the microcomputer 26 (FIG. 7).

The transfer material P carrying the unfixed toner image t (heat-fusible toner) on the upper surface of the transfer material P conveyed from the transfer unit 61 (FIG. 3) to the fixing device 1 by the conveyance device 65 with the endless film 11 interposed therebetween. The unfixed image surface enters between the film 11 and the pressure roller 15 of the pressure contact portion (fixing nip portion) N formed by the heater 14 and the pressure roller 15 so that the unfixed image surface becomes the transfer material P.
At a speed substantially the same as the transport speed of the film 11, and passes through the fixing nip N while receiving the clamping pressure in a state of being overlapped with the film 11 in a plane moving state in the same direction. In this process, the toner image bearing surface of the transfer material P is heated by receiving the heat of the heater 14 via the film 11, and the toner image t is completely softened and melted at least in the surface layer portion, and is thermally fixed to the transfer material P surface. . The transfer material P that has passed through the fixing nip portion N is separated from the surface of the film 11 at the curvature of the film 11 along the roller 13 when the transfer material P passes through the position of the film drive roller 13.

(C) Film-Side Movement Control Mechanism The drive roller 13 and the driven roller 12 of the endless film 11 are supported between the front side plate 19 and the rear side plate 18 of the fixing device 1 as shown in FIG. It is arranged. 21
Reference numeral 20 denotes a front end bearing and a rear end bearing of the driven roller 12.

Here, the driving roller 13, the driven roller 12,
The parallelism of the heater 14 and the pressure roller 15 (X-axis direction,
Unless the accuracy in the (Y-axis direction, Z-axis direction) is set to ± 0, when the drive roller 13 is driven to rotate the film 11 in the direction of arrow a, the film 11 Due to the positional relationship (variation in the X, Y, and Z axes) of the three members of the rollers 13 and 12 and the heater 14, the length of the rollers 13 and 12 is longer than the initial position of the film 11 shown by the solid line in FIG. Is shifted to the right or left in the film width direction along the side plate 18 or the side plate 18 or the side plate 19.
In this case, the edge of the film may be rubbed and damaged.

Therefore, in this embodiment, the driven roller 1
2 is supported on the side plate 18 with a degree of freedom of movement in the front and rear directions of arrows A and B with respect to the side plate 18, and is normally urged to move in the forward direction A by the compression spring 22 as indicated by the solid line. At the first position, it is received by a stopper (not shown), and the plunger of the solenoid 23 is connected. When the energization of the solenoid 23 is turned on, the bearing 20 is pulled in the retreating direction B against the compression spring 22. Then, the position is displaced to the second position indicated by the two-dot chain line.

That is, energization ON / OFF of the solenoid 23
Thus, the degree of parallelism of the driven roller 12 with respect to the driving roller 13 and the heater 14 can be changed.

In this embodiment, when the solenoid 23 is off and the bearing 20 is at the first position shown by the solid line, the rotating film 11
Moves toward the left side in the film width direction, that is, toward the far end side of the rollers 13 and 12 along the length of the suspended tension members 13, 12 and 14 along the length thereof. Is in the second position shown by the two-dot chain line, the rotating film 11 moves to the right in the film width direction, that is, toward the front ends of the rollers 13 and 12, in contrast to the above.

Reference numeral 16 denotes a photosensor for detecting the position of the film shift. Also, as shown in FIG. 1, the front end 3 of the film 11 is masked as indicated by hatching so as to block the light of the photosensor 16 around the entire edge.

In this embodiment, a photo-interrupter is used for the photosensor 16. However, when a reflection-type photosensor is used here, the end portion 3 of the film 11 is treated with a reflection member that reflects light. is necessary. Alternatively, the image may be read by a photo sensor via a movable piece that moves along the edge of the film 11.

In this embodiment, the processing such as masking is performed only on one end of the film 11, but it goes without saying that the processing may be performed on the entire film.

Reference numeral 4 denotes a cleaning member at the edge of the film. The edge of the film is always cleaned so as to prevent erroneous reading when a reflection type sensor is used due to contamination of the edge of the film. Is what it is. In the present embodiment, felt is used, but any type may be used as long as it has a cleaning effect.

FIG. 4 shows the outer shape of the film 11. This film is an endless belt as described above, and its diameter is φM. Also, as shown in the figure, film 1
One end (the front end) of 1 is cut diagonally,
Let the length of the longest part be Lmax and the length of the shortest part be Lm
If in, the dimension of the obliquely cut portion (oblique cut portion) of the film 11 is obtained by Lmax-Lmin, and is set to ΔL (the oblique cut amount of the film) here. The oblique cut portion is arranged on the front side of the main fixing device as shown in FIG. 1 so that the photo sensor 16 detects the position of the film 11.

FIG. 5 is a detailed view of the positional relationship between the photo sensor 16 and the film 11. In this embodiment, the photo sensor 1
A transmission type photo-interrupter is used for 6 and its detection position is indicated by b. This is film 11
Is on the back side of the position b, the photo sensor 16 is ON
In the case of being on the near side of the position b, the switch is turned off. Further, the oblique cut portion of the film 11 is configured to be at the position of the detection position b.

That is, the film 11 is formed by the arrow a shown in FIG.
The photo sensor 16 is turned to O
N / OFF is repeated, and the ON / OFF cycle ratio (duty) depends on the film position (deviation position).
Ratio) will be variable.

The film position shown in FIG.
6 represents a reference position where the center of the oblique cut portion of the film 11 is located at the detection position b. The film position and OFF of the photo sensor 16 are centered on the reference position of the film.
The relationship of time is shown in the graph of FIG.

As shown in FIG. 6, when the film 11 is at the reference position b, the OFF time of the photosensor 16 is c seconds, and the film 11 is located at least ΔL / 2 or more in front of the reference position b. At this time, the OFF time of the photo sensor 16 is 0 second.

Conversely, when the film 11 is located at least ΔL / 2 behind the reference position b, the photo sensor 16 is kept off.

Here, the OF in the case where the shift position of the film 11 is immediately before the position where the photo sensor 16 is kept turned off.
The F time is d seconds, which can be considered to be substantially the same as the time for the film 11 to make one round, and the OFF time c seconds at the reference position b is the center of the film oblique cut portion. The time is almost half of d seconds.

(D) Film-Side Movement Control Circuit FIG. 7 is a schematic diagram of a control system.

Reference numeral 26 denotes a microcomputer, and the photo sensor 16 is connected to an input terminal IN1 of the microcomputer. A solenoid 23 is connected to the OUT1 terminal. An OUT2 terminal outputs a rotation control signal of the motor 27 that also drives the fixing device.

A + 5V power supply is connected to the VDD terminal.
The GND terminal is connected to the ground.

Although not shown, other input and output signal terminals of a copying machine using the present fixing device are provided, and a microcomputer 26 has a copying operation system for the copying machine. A built-in non-volatile RAM, which retains its stored contents even when power supply to the microcomputer 26 is cut off, together with a ROM and a RAM in which a can program and the like are programmed.

The detected temperature information of the first thermistor RT1 (FIG. 2) for detecting the temperature of the heater 14 is input to the analog input port AN1 of the microcomputer 26. The microcomputer 26 is provided with the thermistor R
A signal is sent to the heater energizing circuit 25 so that the temperature of the heater 14 detected by T1 becomes a predetermined substantially constant temperature.
4 is controlled (temperature control control).

The detected temperature information of the second thermistor RT2 (FIG. 2) for detecting the temperature of the pressure roller 15 is input to the analog input port AN2 of the microcomputer 26. In the microcomputer 26, as shown in the flowchart of FIG.
For example, when the temperature is equal to or higher than 150 ° C., the shift control flag is turned ON (step 30 → step 31). When the temperature is lower than 150 ° C., the shift control flag is turned off (step 30 → 3).
2). Then, as described later, the shift control range is switched between a first shift control range and a second shift control range in accordance with this flag.

(E) Control Program FIGS. 8 to 12 show flowcharts of a film shift movement control program of the fixing device.

This program is also programmed in the above-mentioned built-in ROM in the microcomputer 26, and is called and executed by a main sequence program or the like at regular time intervals or as needed. It has become.

First, after the start, in step 1 (FIG. 8), it is determined whether or not the motor 27 is ON. If the motor 27 is on, the process proceeds to step 2, and if the motor 27 is off, the process returns to step 1 and waits until the motor 27 is turned on.

Next, in step 2, it is determined whether or not the film has been controlled so as to approach the front side. This means that the content of a predetermined address in the nonvolatile RAM in the microcomputer 26 is set as a near side flag, and when the state of the memory is 1, that is, when the memory has been controlled to the near side, the step is performed. Step 3 is performed, the solenoid 23 is turned on, and the deviation control is set to the near side.
Move to. In step 2, the front flag is set to 0.
In the case of, since the film has been controlled so as to be shifted to the far side, the process proceeds to step 4 as it is.

At step 4, it is determined whether or not the sensor 16 is off. If the sensor 16 is on, the process proceeds to step 8, and if it is off, the process proceeds to step 5.

In step 5, the value of the error timer is reset to 0, measurement is started, and the process proceeds to step 6.

In step 6, it is determined whether or not the sensor 16 is ON. If not, the process proceeds to step 7.

In step 7, an error check routine is executed, and the process returns to step 6.

The contents of the error check routine will now be described with reference to FIG.
It is determined whether or not 7 is ON. If ON, the process proceeds to step S2.
Move to (FIG. 9).

In step S2, it is determined whether or not the error timer value is greater than d seconds. If the error timer value is less than d seconds, the process proceeds to the exit of this routine. If the error timer value is greater than d seconds in step S2, step S
It will shift to 3. In step S3, an error flag is set, and the routine goes to the exit of this routine.

Next, at step 6, the sensor 16
If N, the process proceeds to step 8 to reset the value of the error timer to 0, start the measurement, and proceed to step 9. In step 9, it is determined whether or not the sensor 16 is OFF. If the sensor 16 is not OFF, the process proceeds to step 10 to execute an error check routine and returns to step 9, and if the sensor 16 is turned off, the process proceeds to step 11. Then, the value of the timer 1 is reset to 0 and the measurement is started, and the process proceeds to step 12 (FIG. 9).

In step 12, it is determined whether or not the motor 27 is ON. If the motor 27 is ON, the process proceeds to step 14.

At step 14, it is determined whether or not the sensor 16 is ON.
The process proceeds to step 5 to execute an error check routine, and returns to step 14. If it is ON, the process proceeds to step 27.

At step 27, it is determined whether or not the shift control flag is ON. In this embodiment, the first deviation control range is d / 4 to 3d / 4, and the second deviation control range is 2d / 5 to 3d / 5. If the flag is ON in step 27, the process proceeds to step 28, where control is performed in the second shift control range, and
If not, the process proceeds to step 16 to perform control in the first shift control range.

In step 28, the measured value of the timer 1 is 2d
A comparison is made to determine whether or not the time is shorter than / 5 seconds. If the time is shorter, it can be determined that the film 11 is located on the front side of the second shift control range. The approach direction of the film 11 is switched to the back side, the front flag is reset to 0, and the process proceeds to step 20.

If the measured value of the timer 1 is not smaller than 2d / 5 seconds in step 28, the flow shifts to step 29.

In step 29, the value measured by the timer 1 becomes 3
It is comparing whether it is larger than d / 5 seconds,
If it is not larger, the process proceeds to step 20. If it is larger, it can be determined that the film 11 is located on the far side of the second shift control range.
3 is turned on to switch the direction of shifting of the film 11 to the near side, the foreground flag is set to 1, and the routine proceeds to step 20.

In step 16, the measured value of timer 1 is set to d /
A comparison is made as to whether the time is less than 4 seconds. If the time is smaller than 4 seconds, it can be determined that the film 11 is located closer to the front side than the first shift control range. The direction of the approach 11 is switched to the back side, the front flag is reset to 0, and the process proceeds to step 20.

If the measured value of the timer 1 is not smaller than d / 4 seconds in step 16, the process proceeds to step 18.

At step 18, the measured value of the timer 1 becomes 3
It is comparing whether it is larger than d / 4 seconds,
If it is not larger, the process proceeds to step 20. If it is larger, it can be determined that the film 11 is located farther than the first shift control range.
3 is turned on to switch the direction of shifting of the film 11 to the near side, the foreground flag is set to 1, and the routine proceeds to step 20.

In step 20, the value of the error timer is reset to 0 and measurement is started, and the process proceeds to step 21.

In step 21, it is determined whether or not the sensor 16 is OFF. If the sensor 16 is not OFF, the process proceeds to step 22, executes an error check routine, and returns to step 21.

In step 21, the sensor 16
In the case of FF, the process proceeds to step 23, where the value of the timer 1 is reset to 0, measurement is started, and the process returns to step 12.

In step 12 described above, the motor 27
In the case of the FF, the process proceeds to step 13, where the measurement of the timer 1 is stopped, the measured value is reset to 0, the solenoid 23 is turned off, and the process returns to step 1.

FIG. 11 shows a flowchart of a film abnormality processing program which is a part of the main program. Here, it is determined in step 24 whether or not the error flag is set. If the error flag is not set, the process proceeds to the exit and the next main sequence program is executed.

If the error flag is set in step 24, the flow goes to step 25 to turn off all the outputs of all the devices (the copying device in this embodiment), and then goes to step 26 to move to the film An abnormality is displayed and the step 26 is set as a permanent loop so that the main program cannot be executed.

As described above, the endless film 11 of the present fixing device starts from the time of rotation of the motor, and the non-volatile R which stores the shift direction controlled up to that time.
The solenoid 23 is controlled according to the content of AM. Next, when the sensor 16 is ON when the motor is rotating, wait until the sensor 16 is turned OFF, and when the sensor 16 is OFF, wait until the sensor 16 is turned ON and then wait until the sensor 16 is turned OFF. The timing of switching to OFF is detected, and the initial setting ends. Then, the position of the film 11 is detected only by measuring the OFF time of the sensor 16 until the sensor 16 switches from OFF to ON.

Thereafter, the OFF time of the sensor 16 from the timing when the sensor 16 switches from ON to OFF until the sensor 16 switches from OFF to ON is measured so that the film position falls within a predetermined control range corresponding to the temperature of the pressure roller. Is controlled.

In this embodiment, a transmission type photosensor is used as the sensor 16, but it goes without saying that the same applies to a sensor such as a microswitch or a reflection type photosensor.

Further, a plurality of thermistor units may be provided, and the control may be changed depending on the detected temperatures of many members.

Second Embodiment (FIG. 13) The shift control range may be switched according to the temperature of the fixing film. In this embodiment, as shown in FIG. 13, the temperature of the fixing film 11 is detected by pressing the thermistor unit 24 against the surface of the fixing film 11 at the position of the drive roller 13. When the temperature of the fixing film 11 is equal to or higher than the predetermined temperature, the control is performed in the second shift control range, and when the temperature is lower than the predetermined temperature, the control is performed in the first shift control range. Other configurations and controls are the same as those in the first embodiment.

The same applies when the thermistor unit 24 is attached to another fixing device component such as the driving roller 13 or the roller 12, or the side plate 18 or 19, and the control is switched according to the temperature of the component.

<Third Embodiment> (FIG. 14) This embodiment is a thermistor RT for detecting the temperature of the heater 14.
1 is used to switch the shift control range. FIG.
Reference numeral 4 denotes a flowchart of this embodiment, which is called at the start of copying.

In step 101, it is determined whether or not copying has started. When copying is started, the process proceeds to step 102. In step 102, the temperature of the heater 14 is determined from the value of the thermistor RT1. If the temperature of the heater 14 is 150 ° C. or less, step 1
04 and turns off the control flag. Thereafter, the routine proceeds to step 105, where the motor is turned ON, the heater energization is started, and the routine exits. The other deviation control is the same as in the first embodiment.

As in the present embodiment, the heat storage of the fixing device can be determined by determining the temperature before the heater is energized, and a similar result can be obtained by switching the shift control range. <Fourth Embodiment> In this embodiment, thermistors 28 and 29 (FIG. 1) are attached to both the front side plate 19 and the back side plate 18 of the apparatus 1 to detect the temperatures of the front side and the back side of the apparatus.
Then, the near-side control range and the back-side control range are changed according to the temperature difference between the near side and the back side.

For example, when the temperature of the front side plate is higher than the temperature of the rear side plate by 50 ° C. or more, the near side control range is set to 2 d / 5 seconds.
The control range on the back side is set to 3d / 4 seconds. In this way, even if there is a temperature difference between the front and the back, the movement can be controlled from a stable film.

[0096]

As described above, according to the present invention, for a film heating type image heating apparatus using an endless film, even if a change in the film shift speed due to a temperature factor or a change in durability occurs, the reciprocation frequency of the film shift control reciprocation. Can be suppressed to a certain range, thereby preventing excessive stress on the film and eliminating wrinkles and the like.
In addition, erroneous detection of the film and temperature rise of the solenoid can be minimized, and the displacement of the film, the heating element, and the heating element supporting member can be reduced by abrasion of the same part. Life can be extended. It can be implemented without increasing the complexity of the film shift control mechanism, making it possible to realize stable film transport for film heating type image heating devices using endless films and improve the reliability of the device. Was.

[Brief description of the drawings]

FIG. 1 is a partially omitted plan view of an example of a heating device according to the present invention.

Fig. 2 Side view

FIG. 3 is a schematic configuration diagram of an example of an image forming apparatus using the heating device as a fixing device.

Fig. 4 Outline drawing of endless film

FIG. 5 is a diagram showing a relationship between a film sensor and a film position.

FIG. 6 is a graph showing a relationship between a film position and a film sensor output.

FIG. 7 is a schematic diagram of a control system.

FIG. 8 is a flowchart of a film shift control program.

FIG. 9 is a flowchart of a film shift control program.

FIG. 10 is a flowchart of a film shift control program.
Chart

FIG. 11 is a flowchart of a film shift control program.
Chart

FIG. 12 is a flowchart for determining a film shift movement control range.

FIG. 13 is a side view of the device according to the second embodiment.

FIG. 14 is a control flowchart of the apparatus according to the third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Endless film fixing sheet 12 Follower roller 13 Drive roller 14 Fixing heater 15 Pressure roller 16 Photosensor 23 Solenoid 26 Microcomputer 27 Motor RTI, RT2 Thermistor

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03G 15/20

Claims (4)

(57) [Claims] And 1. A shaped rotatable endless film,
Has a deviation control means for deviation of the film in the direction perpendicular to the moving direction of the film is controlled to be within a predetermined range, a pressure member in contact with the film, the said
Recording carrying an image at the contact portion between the film and the pressing member
In an image heating apparatus for nipping and conveying a material and heating an image on a recording material by heat from the film side, the image heating device has a temperature detecting means for detecting a temperature of the pressing member, and detects a temperature detected by the temperature detecting means. An image heating apparatus, wherein the width of the predetermined range is changed by the shift control means in response to the change. 2. A rotatable endless film,
Image shift control means for controlling the shift of the film in a direction perpendicular to the direction of movement of the film to be within a predetermined range, and heating the image on the recording material by heat from the film side. An image heating apparatus, comprising: a temperature detecting means for detecting a temperature of the film; and changing a width of a predetermined range by the shift control means according to a temperature detected by the temperature detecting means. 3. A heating element, and a rotatable member that slides on the heating element.
Endless film and how to move the film
The deviation of the film in the direction perpendicular to the direction is within the specified range.
Control means for controlling the
The image on the recording material by the heat from the heating element through the
In an image heating device for heating, the image heating device has a temperature detection unit for detecting a temperature of the heating body ,
The deviation control means according to the temperature detected by the temperature detection means
An image heating apparatus you and changing the width of a predetermined range due. 4. An endless rotatable film,
Of the film in a direction perpendicular to the moving direction of the film
Deviation control means for controlling the deviation to be within a predetermined range
And, on the recording material by heat from the film side
In an image heating apparatus for heating an image, there is provided temperature detecting means for detecting temperatures near both ends of the film in a direction orthogonal to the moving direction of the film.
And, an image heating apparatus you and changing the width of the predetermined range by the shift control means in accordance with the difference between the detected temperature from said temperature detecting means.