JP3013537B2 - 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. In addition, when a film detection failure or a driving means for displacing the film-suspending conveyance roller, for example, a solenoid is used, the driving frequency of the solenoid increases, and the solenoid itself may be heated more than necessary. These condition settings can be optimized in the initial state by component accuracy, adjustment, and the like. However, the above-mentioned film shift speed is an unstable factor because a change in durability or the like is expected.

[0010] Particularly, unlike the general film (belt) conveyance, the present apparatus is a heating apparatus.
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.

It is also known that in a film heating type heating apparatus, 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.

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

[0013] Further, the heat is absorbed by a material to be heated such as a recording material to be heated and fixed to be introduced into the apparatus, so that a temperature distribution imbalance can be caused in the longitudinal direction of the heating portion, or a non-uniformity due to the introduction of a small-sized material to be heated can occur. The temperature distribution unbalance due to the rise in the temperature of the paper passing portion also causes the film-slope speed to change, thereby making the film-slope condition unstable.

Accordingly, the present invention relates to a film heating type heating apparatus using an endless film provided with the above-described film shift movement control mechanism, the temperature along the longitudinal direction of the heating section due to the size of the material to be introduced. Stable film deviation control that prevents film detection errors without causing film damage, wrinkles, etc. even if the film deviation speed changes due to distribution imbalance or excessive temperature rise in the non-paper passing area And to improve the reliability of the device.

[0015]

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

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 so as to be within a predetermined range. An image heating apparatus that heats an image on a recording material by detecting a width of the recording material in a direction orthogonal to a moving direction of the film, and performing the deviation control according to a detection width from the detecting device. An image heating apparatus characterized in that a predetermined range is changed by means.

<Operation> That is, by switching the film-side movement control range according to the width size information of the recording material to be introduced into the apparatus, the heat is absorbed by the introduced recording material, so that the temperature distribution unfolds with respect to the length of the heating section. Even if the film shift speed changes due to the ability to balance and the temperature distribution unbalance due to the rise in the temperature of the non-sheet passing portion due to the introduction of a small-sized recording material, the film movement distance range of the film reciprocation in the film shift control Is variable, it is possible to suppress the reciprocation frequency of the film shift control 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 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. .

[0018]

【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 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 platen glass disposed on the upper plate 51 of the copier housing 50, which is reciprocally driven in the left and right direction 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 downwardly reflected light from the original surface of the slit illumination light is sequentially imaged and exposed by an imaging lens (short focus imaging element array) 57 on the surface of a photosensitive drum 58 which rotates in synchronization with the scanning of the original image.

The photosensitive drum 58 is subjected to a uniform positive or negative charging process by a discharger 59 and then subjected to the above-mentioned image forming exposure, so that an electrostatic latent image corresponding to a document 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 into the copying machine by the paper feed roller 63, and the leading end is received at the nip portion of the registration roller pair 64 which is in a rotation stopped state at that time. Here, the photosensitive drum 5
The rotation of the registration roller pair 64 is started at a predetermined timing synchronized with the rotation of the rotation of the transfer roller 8, whereby the transfer material P is guided by the guide member and fed toward the photosensitive drum 58, and is transferred to the photosensitive drum 58. The developed image on the surface of the photosensitive drum 58 is sequentially transferred to the transfer material P introduced into the transfer section between the discharge units 61 for use.

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 driving 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 μ, more preferably less than 40 μ. 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 side 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.

Reference numeral 15 denotes a pressure roller having a rubber elastic layer of silicon rubber or the like having good releasability, and a pressing portion (not shown) sandwiching the film portion on the lower side of the endless film 11 between the pressing roller and the heater 14. 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.

The transfer material P, which has been transported from the transfer section 61 (FIG. 3) to the fixing device 1 by the transport device 65 and carries the unfixed toner image t (heat-fusible toner) on the upper surface, sandwiches the endless film 11. 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.

Numeral 16 denotes a photo sensor for detecting the position of the shift of the film. 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 film edge cleaning member. The film edge is always cleaned so as to prevent erroneous reading when a reflection type sensor is used, for example, due to contamination of the film edge. 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 and closer to the near side than 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. 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 switches SW1 to SW4 for detecting the code of the sheet cassette mounted on the image forming apparatus are connected to the input ports IN2 to IN5 of the microcomputer 26. When this switch is selectively pressed and turned on by a claw on the loading paper cassette described below, information on the size of the transfer material contained in the cassette (that is, information on the width of the transfer material) is input to the microcomputer 26. I do.

(E) Transfer Material Size Detecting Means FIG. 8 is a view of the paper feed cassette 62 viewed from the rear. When paper is set in the cassette, the pawl 7 behind the paper feed cassette is used.
1 is set to a predetermined value corresponding to the size of the accommodated paper, and the paper feed cassette 62 is mounted on the image forming apparatus.
Is selectively turned on by the claw 71, so that the cassette 6
2 can be detected. In the case of FIG. 8, when the claw 71 is on, it becomes "1" at the input ports IN2 to IN5 of the microcomputer 26, and when it is not on, it becomes "0". For example, if the 4-bit signal is “0110”, it is determined that A4 size paper is in the cassette 62.

As described above, the size of the transfer paper is determined by detecting the pawl 71 of the paper feed cassette 62, and the film deviation control range is switched accordingly as described later. In the present embodiment, when the width of the fed transfer material P is less than half the width of the film 11, it is the second shift control range, and when it is more than half, it is the first shift control range.

(F) Control Program FIGS. 9 to 13 show flowcharts of a film shift control program of the fixing device.

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

First, after the start, in step 1 (FIG. 9), it is determined whether or not the motor 27 is ON. If the motor 27 is ON, the process proceeds to step 2, and a subroutine for determining the film deviation control range based on the paper size (transfer material width size) is called. If the motor 27 is off, the process returns to step 1 and waits until the motor 27 is turned on.

FIG. 13 shows a routine for determining the film deviation control range based on the paper size. In step 30, the input ports IN2 to IN2 of the microcomputer 26 (FIG. 7)
The state of the switches SW1 to SW4 connected to N5 is read. The paper size is determined from the result of this input. Next, the process proceeds to step 31, where it is determined whether the paper size width is smaller than 1/2 of the width of the film 11. If it is smaller, the process proceeds to step 32, and the paper size flag is turned on.
At 3, the paper size flag is turned off.

Next, in step 2, it is determined whether or not the film has been controlled so as to be shifted to the near 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.

At step 5, the value of the error timer is reset to 0, measurement is started, and the routine goes 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.

Here, the contents of the error check routine will 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. 10).

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. 10).

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.

In 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.

In step 27, it is determined whether the paper size 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.

At step 28, the value measured by 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 process proceeds 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.

In step 18, the value measured by 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 not, 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. 12 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 (copying device in this embodiment). 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 with the non-volatile R which stores the shift direction which has been controlled before 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 to determine the film position and the paper size width. The control is performed so as to be within the control range.

In this embodiment, a transmission type photo sensor is used as the sensor 16. However, it goes without saying that the same applies when a sensor such as a micro switch or a reflection type photo sensor is used.

In this embodiment, the control range for the back side and the control range for the front side are simultaneously switched. However, only the range on the back side may be changed. Further, the deviation control range may be switched to a plurality according to the paper size.

<Second Embodiment> (FIGS. 14 and 15) FIG. 14A shows a manual tray portion of a manual paper feed type image forming apparatus. The transfer material P is placed on the manual feed tray 80 by inserting the leading end of the transfer material P into the nip portion between the feed roller 81 and the tray 80. The paper feed roller 81 is driven to rotate by the paper feed start signal, and the transfer material P on the tray 80 is fed into the apparatus, and is fed to the image transfer unit via the registration roller 64.

Reference numerals 82 and 83 denote optical sensor arrays as paper size detecting means disposed downstream of the paper feed roller 81 in the transfer material feeding direction. FIG. 14B is a perspective view of the optical sensor array portion.

Reference numeral 82 denotes an LED array as a light emitting side;
Denotes a phototransistor array on the light receiving side, which is arranged to face each other. The transfer material P fed from above the tray 80 by the paper feed roller 81 is
And the phototransistor array 83, the portion through which the paper (transfer material) passes during the passing process is where the light emission of the LED array 82 to the phototransistor array 83 on the light receiving side is blocked, and the portion that does not pass through is LED
The detection signal obtained from the phototransistor that has received the array light and received the light is a paper size detection microcomputer 84 shown in FIG.
Through the input ports IN2 to IN2 of the microcomputer 26.
It is output to IN5 as a 4-bit signal.

Therefore, the same operation as in the first embodiment can be performed, and the same effect can be obtained. The optical sensor arrays 82 and 83 may be provided anywhere in the paper transport section from the paper feed section to the entrance of the fixing device.

<Third Embodiment> (FIG. 16) This embodiment is another embodiment of the paper size detecting means.

FIG. 16A shows a manual paper feed type image forming apparatus similar to that shown in FIG.
As paper size detecting means in a direction downstream feeding the transfer material feeding than 1, and Tsumearei 86 arranged claws 85 ₁ ... 85 ₆ of retractable ((b) is a perspective view thereof), is opposed to this Tsumearei 86 A paper holder 88 is arranged. Claw array 8
The 6 are arranged a photo-interrupter 87 ₁ ... 87 ₆ respectively corresponding to Kakuka倒claws 85 ₁ ... 85 _6.

The transfer material P fed from above the tray 80 by the paper feed roller 81 passes between the claw array 86 and the paper retainer 88, and passes through the transfer material passage portion in accordance with the width of the fed transfer material P. The claws 85 ₁ … 85 ₆ are selectively collapsed, and the photo-interrupters 87 ₁ … 87 ₆ corresponding to the claws that have fallen.
((C) → (d)), and the signal is input to the microcomputer (26) to detect the paper size.

Therefore, the same operation as that of the first embodiment can be performed, and the same effect can be obtained. In addition, the sensor 8 of the present embodiment
6.88 may be provided anywhere in the paper transport section from the paper feed section to the entrance of the fixing device.

[0095]

As described above, according to the present invention, in a film heating type image heating apparatus using an endless film, a temperature distribution imbalance can be caused by heat being introduced by an introduced recording material, and a non-paper passing state can be achieved. Even if the film distribution speed changes due to the temperature distribution imbalance due to the temperature rise of the part, the film movement distance of the reciprocating motion in the film deviation control is variable, so the reciprocation frequency of the film deviation control can be kept within a certain range Thus, it is possible to prevent excessive stress on the film and eliminate wrinkles and the like. In addition, erroneous detection of the film and the temperature rise of the solenoid can be minimized. Life can be extended. Complicated film shift control mechanism
The present invention can be implemented without increasing the size, and can stably convey a film in an image heating apparatus of a film heating method using an endless film, thereby improving the reliability of the apparatus.

[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 an explanatory diagram of a paper feed cassette and a paper size detecting unit.

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

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

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

FIG. 12 is a flowchart of a film shift control program.
Chart

FIG. 13 is a flowchart for determining a film shift movement control range.

14A is a partial view of a manual sheet feeding type image forming apparatus provided with a paper size detecting unit according to the second embodiment, and FIG. 14B is a perspective view of the paper size detecting unit.

FIG. 15 is a schematic diagram of a control system.

16A is a partial view of a manual sheet feeding type image forming apparatus provided with a paper size detecting unit according to the third embodiment, FIG. 16B is a perspective view of a claw array of the paper size detecting unit,
(C) is a state diagram of the paper size detection unit before the paper passes, (d)
Is a state diagram during paper passage.

[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 71 ・ SW1-SW4 Paper size detecting means 82 ・ 83 Paper size detecting means 86 ・ 88 Paper size detecting means

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

Claims (1)

(57) [Claims] A rotating endless film;
Film in a direction perpendicular to the direction of film movement
Deviation control means for controlling the deviation to be within a predetermined range;
Having an image on a recording material by heat from the film side
An image heating apparatus for heating a recording material in a direction orthogonal to a moving direction of the film.
Detection means for detecting the width of the
Changing the predetermined range by the deviation control means according to the knowledge width
An image heating apparatus, comprising: