JP3067333B2 - Image heating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotating endless shape.
And the direction perpendicular to the direction of movement of this film
Deviation control means for controlling the deviation of the film toward the
Then, the image on the recording material is added by the heat from the film side.
The present invention relates to a heating device for heating an image .

[0002]

2. Description of the Related Art A heating apparatus of the above-mentioned film heating type is known from Japanese Patent Application Laid-Open No. 63-313182, and is an image heating and fixing apparatus in an image forming apparatus such as an electrophotographic copying machine, a printer and a facsimile. That is, electrophotography
Indirectly to the surface of recording material (transfer material sheet, electrostatic recording sheet, electrofax sheet, printing paper, etc.) using toner made of resin which can be heated and melted by image forming process means such as electrostatic recording and magnetic recording. It can be used as an image heating / fixing apparatus that heats and fixes an unfixed visible image (toner image) corresponding to target image information as a fixed image on a recording material carrying the image, which is formed by a (transfer) method or a direct method. . 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] Regarding the image fixing apparatus of the film heating type, there are a hot roller type, a hot plate type, a flash fixing type,
In comparison with other thermal fixing devices such as oven fixing method. Since a low heat capacity linear heating element 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, the rise time to a predetermined fixing temperature can be reduced, and power can be saved. 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 shift control means switches the shift direction of the film between the forward and reverse directions under certain fixed conditions. However, if some external condition is applied, even if the transport means is displaced, the film does not shift in the predetermined direction, that is, if the film runs backward or the film shifts at a rapid speed, Stable film running, such as skew and film wrinkles, cannot be realized.

As the above-mentioned external conditions, the influence of heat is the most important, and it is not necessary to consider an extreme temperature difference in general film (belt) conveyance. In the temperature rising state, the temperature of each component rises to about 150 ° C. to 200 ° C. The rise in temperature naturally changes (generally reduces) the friction coefficient of the conveying means and the surface of the heating element, and the initial reciprocating condition closer to the film may be lost. Also, there is a temperature distribution in the heating element itself, the size of the recording material to be passed, and the temperature rise in the non-sheet passing portion based on one side (the temperature rises in the portion where there is no recording material because there is no escape of heat by the recording material). If so, the conveying means also has a temperature gradient, causing a difference in thermal expansion in the longitudinal direction, and as a result, a shift due to a difference in conveying speed.

Further, due to the durability, the friction coefficient changes due to abrasion of the inner surface of the film, the conveying means, and the surface of the heating element, which also becomes a factor of changing the conditions.

Further, in the film heat fixing device, since the film is conveyed while rubbing the fixedly supported low heat capacity heating element, fluorine-based heat-resistant grease is applied to the inner surface of the film for the purpose of preventing vibration at the rubbing portion and reducing torque. May be lubricated. In this case, since the grease viscosity has a temperature dependency and the grease application state after the initial and endurance changes, this also causes a change in the film shift condition,
This will affect the above-mentioned deviation control.

Accordingly, the present invention relates to a film heating type heating apparatus using an endless film provided with the above-mentioned film shift movement control mechanism. By providing a means for adjusting the film damage,
It is an object of the present invention to improve the reliability of an apparatus by always enabling stable film deviation control and film transport without generating wrinkles or the like.

[0014] (1) against the rotatable endless film, a deviation control means for controlling the deviation of the film in the direction perpendicular to the moving direction of said film, said film
A pressure member that touches , the film and the pressure unit
An image heating apparatus for nipping and transporting a recording material carrying an image at a contact portion of the material and heating an image on the recording material by heat from the film side, comprising a temperature detecting unit for detecting a temperature of the pressing member; an image heating apparatus characterized by controlling the deviation rate of the film by the shift control means in accordance with the detected temperature from said temperature detecting means.

(2) Endless rotatable film
And filling in a direction orthogonal to the direction of movement of the film.
Shift control means for controlling shift of the system,
Image heating that heats the image on the recording material with heat from the lum side
In the apparatus, a temperature detection for detecting the temperature of the film
Means, and according to the temperature detected by the temperature detecting means.
Controlling the shift speed of the film by the shift control means
An image heating device , characterized in that:

(3) A heating element and a rotating member that slides on the heating element.
Rollable endless film and transfer of said film
To control the movement of the film in the direction perpendicular to the moving direction.
And heating means via the film.
Image heating device that heats the image on the recording material by heat from the body
In the above, a temperature detecting means for detecting the temperature of the heating element
The temperature sensor according to the temperature detected by the temperature detector.
Control of the film shift speed by the
Characteristic image heating device. (4) A rotatable endless film and the film
Controls the movement of the film in the direction perpendicular to the moving direction of the film.
Control means for controlling the shift from the film side.
An image heating device that heats an image on a recording material by heat
Te, the temperature detecting means for detecting the temperature near both ends of the direction of the film orthogonal to the moving direction of the film, respectively
A, this <br/> the image heating apparatus you said to control the deviation rate of the film by the shift control means in accordance with the difference between the detected temperature from said temperature detecting means.

< Operation > That is, a pressing member, a film,
By detecting the temperature near the heating element, or both ends of the film and changing the speed toward the film accordingly,
Even if the film deviation movement control becomes unstable due to the heat storage of the device, that is, even if the film deviation speed changes due to temperature factors or durability changes, the film deviation control reciprocating frequency can be suppressed to a certain range, This can prevent excessive stress on the film and eliminate wrinkles and the like. In addition, the shift of the moving distance reduces the rubbing wear of the same portion of the film, the heating element, and the heating element supporting member, so that the life of the entire apparatus can be extended.
The film shift control mechanism can be implemented without increasing the complexity and size of the film shift control mechanism, and includes a rotating endless film and a shift control means for controlling the shift of the film in a direction orthogonal to the direction of movement of the film. An image heating apparatus for heating an image on a recording material by heat from the film side can realize long-term stable conveyance of a film as described above, and can improve the reliability of the apparatus.

[0018]

【Example】

<First Embodiment> (FIGS. 1 to 13) FIG. 1 is a partially omitted plan view of an example of a heating device according to the present invention, FIG. 2 is a side view, and FIG.
Is a perspective view, and FIG. 4 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 (FIG. 4) The image forming apparatus shown in FIG. 4 is an electrophotographic copying machine of a platen reciprocating type, a rotating drum type, and a transfer type.・ Since the image forming process and the like belong to the public domain, only a brief explanation will be given.

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 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 feed cassette 62 by the paper feed roller 63, and the leading end of the transfer material P is received at the nip portion of the registration roller pair 64 at the time of rotation stop. 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 portion between the photosensitive drum 58 and the transfer discharger 61, and is sequentially transferred onto the transfer material P on the photosensitive drum 58 surface side. Is transferred.

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 (FIGS. 1 to 3) 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 and stretched between 12, and the drive roller 13 is driven to rotate clockwise as shown by an arrow a by a drive system (not shown) including a drive motor 27 (FIG. 2); It is rotationally driven at a predetermined peripheral speed in a clockwise direction. 22
FIG. 1 shows a compression spring that biases the driven roller 12 as a tension roller.

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 carrying the unfixed toner image t (heat-fusible toner) on the upper surface of the transfer material P transported from the transfer unit 61 (FIG. 4) to the fixing device 1 by the transport 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 shift control mechanism (FIG. 1)
FIG. 3) The drive roller 13 and the driven roller 12 of the endless film 11 are disposed between the front side plate 19 and the rear side plate 18 of the fixing device 1 as shown in FIG. 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,
When the drive roller 13 is driven (Y-axis direction, Z-axis direction) to rotate the film 11 in the direction indicated by the arrow a, the film 11 is rotated by the rollers 13 and 12 and the heater Due to the positional relationship of the three members (variation in each direction of the X, Y, and Z axes), the initial position of the film 11 indicated by the solid line in FIG. A shift occurs to the rear side direction C) or to the left side (front side direction B of the apparatus), so that the end of the film rubs against the side plate 18 or the side plate 19 and is damaged.

In the present embodiment, the bearing 21 on the front side of the driven roller 12 has a degree of freedom of movement in the vertical direction directly with respect to the side plate 19 in the directions indicated by arrows P and Q in FIG.
The parallelism of the driven roller 12 with respect to the driving roller 13 can be changed by vertically moving P · Q by a fork arm 24 that is driven to swing vertically by a stepping motor 23.

When the stepping motor 23 rotates clockwise, that is, when the arm 24 rotates clockwise U, the front end of the driven roller 12 is displaced in the direction of arrow P. When the front end of the driven roller 12 is lifted in the direction indicated by the arrow P, the film 11 is set to shift in the direction indicated by the arrow B on the front side. Conversely, the stepping motor 23 rotates counterclockwise,
Is rotated in the counterclockwise direction D, so that the front end of the driven roller 12 is lowered, so that the film 11 is shifted in the direction of the arrow C on the back side.

In this embodiment, the stepping motor 23 is rotated clockwise in accordance with the output of a temperature detecting means to be described later so as to lift the driven roller 12 upward. , And conversely, the stepping motor 23 is rotated counterclockwise so that the driven roller 12 is lowered, whereby the film 11 is set to be shifted toward the back of the apparatus. At this time, by controlling the number of drive pulses applied to the stepping motor 23, the amount of inclination of the driven roller 12 can be changed, and the speed of the endless film 11 can be varied.

Numeral 16 denotes a photo sensor for detecting the position of the shift of the film. 1 and 3
As shown in the figure, the front end 3 of the film 11 (shaded portion)
Is masked so as to block the light of the photo sensor 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 position of the film 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 for the film end 3, which is always cleaned so as to prevent erroneous reading when a reflection type sensor is used due to contamination of the film end. Is what you are doing. In the present embodiment, felt is used, but any type may be used as long as it has a cleaning effect.

FIG. 5 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. 6 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, when the film 11 rotates in the direction of arrow a, the photosensor 16 repeats ON / OFF, and the ON / OFF cycle ratio (duty ratio) depends on the film position (deviation position). 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. 7, 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. 8 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 stepping motor 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 thermistor RT1 is connected to the analog input port AN1 of the microcomputer 26, and the thermistor RT2 is connected to the analog input port AN2. Thermistor RT
1 is attached near the fixing device, and detects the temperature of the heater 14. The microcomputer 26 sends a signal to the power supply circuit 25 so that the temperature of the heater 14 detected by the thermistor RT1 becomes constant, and controls the temperature of the heater 14.

Then, the temperature of the pressure roller 15 is detected by the thermistor RT2. As shown in FIG. 13, when the temperature of the pressure roller 15 is a predetermined temperature, for example, 150 ° C. or higher, the displacement of the driven roller 12 is 40 steps, and when the temperature is 150 ° C. or lower, the step is 20 steps. To save. At this time, the driven rollers 12 are each 4 mm.
And 2 mm. In this way, the displacement of the driven roller 12 is controlled according to the temperature of the pressure roller 15 based on the temperature of the pressure roller 15.

(E) Control program FIGS. 9 to 12 show flowcharts of a film shift movement 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 if the motor 27 is off, the process returns to step 1 and waits until the motor 27 is turned on.

In step 2, the stepping motor 23 for initial control is initialized. In the initialization operation, the stepping motor 23 is rotated counterclockwise, and is rotated until the driven roller 12 descends to a predetermined lowermost position. Thereafter, the lowest position is set to 0, and the axis position is controlled by the number of pulses from this point. Next, the routine proceeds to step 101.

In step 101, 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. The process moves to 103, and the stepping motor 23 is rotated clockwise to a pulse position where the driven roller 12 is higher than the middle point by the amount of displacement.

In this embodiment, the middle point is a position 50 steps from the above-mentioned zero point, and the displacement is
The number of steps is determined by the temperature of 5. Assuming that the temperature of the pressure roller 15 is 150 ° C. or less, the stepping motor 23 is rotated for 70 steps. The position at this time is stored in the RAM. When the front flag is 0, the motor 23 is turned to the position [50-displacement amount], and the step position is stored in the RAM.

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 16.

In step 16, the measured value of timer 1 is set to d /
A comparison is made as to whether or not 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 on the front side of the first shift control range. −displacement amount], the current position is stored in the RAM, the direction of shifting of the film 11 is switched to the back side, the front flag is reset to 0, and the routine proceeds to step 20.

If it is determined in step 16 that the measured value of the timer 1 is not smaller than d / 4 seconds, 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 on the back side of the first shift control range. Therefore, the process proceeds to step 19 until the stepping motor 23 becomes [50 + variable position]. By turning clockwise, the current position is stored in the RAM, the approach direction of the film 11 is switched to the near side, the near 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.

At 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 first stopped, the measured value is reset to 0, then all the phase excitations of the stepping motor 23 are turned off, and the process returns to step 1.

Although not described in detail, the driving of the stepping motor 23 is performed with respect to the current position in the RAM.
For example, when the current position is at 30 steps and at 70 steps, it is moved clockwise by 40 steps. Current position is 3
To move to the position of 10 steps at 0 step, move 20 steps counterclockwise.

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 outputs of all the devices (copiers in this embodiment), and then goes to step 26 to go to film 26. 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.
The stepping motor 23 is controlled according to the content of AM. Next, when the sensor 16 is ON during the rotation of the motor,
The output of the film position sensor 16 is changed from ON to OFF by waiting until the FF is turned off, and when the sensor 16 is OFF, waits until the sensor 16 is turned ON and then turns OFF.
The timing of switching to 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 time when the sensor 16 switches from ON to OFF to the time when the sensor 16 switches from OFF to ON is measured and the film position is controlled to be within a predetermined control range.
The displacement of the driven roller is controlled by the displacement according to the temperature of the pressure roller.

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

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. 14) The amount of displacement of the film transport means for controlling the shift to the film may be changed according to the temperature of the fixing film. In this embodiment, as shown in FIG. 14, the temperature of the fixing film 11 is detected by pressing the thermistor TR2 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 a predetermined temperature, the displacement is controlled in 40 steps, and when the temperature is lower than the predetermined temperature, the displacement is controlled in 20 steps. Other configurations and controls are the same as those in the first embodiment.

Further, the thermistor TR2 is
The same applies if the control is switched to another fixing device component such as the roller 12 or the side plates 18 and 19 in accordance with the temperature of the component.

<Third Embodiment> (FIG. 15) In this embodiment, the shift control displacement is switched using a thermistor RT1 for detecting the temperature of the heater 14. FIG. 15 is 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 is equal to or higher than a predetermined temperature, for example, 150 ° C., the process proceeds to step 103 and the control change position is set to 40 steps.
If the temperature of the heater 14 is equal to or lower than 150 ° C., the process proceeds to step 104, where the control displacement amount is set to 20 steps. 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> (FIG. 16) In this embodiment, as shown in FIG. 1, both the front side plate 19 and the rear side plate 18 of the apparatus 1 are provided with thermistors T.
R3 and TR4 are attached to detect the temperatures of the near side and the far side of the apparatus. Then, the front-side displacement amount and the back-side displacement amount are respectively changed according to the temperature difference between the near side and the back side.

In this way, it is possible to cope with the film-side speed balance caused by the temperature difference between the front and the back.

FIG. 16 shows a routine called to determine the amount of displacement. When the temperature of the front side plate 19 is higher than the temperature of the rear side plate 18 by 50 ° C. or more, it is difficult to shift to the front side. Therefore,
The displacement amount shifted to the back side is set to 40 steps. In the opposite case, the amount of displacement approaching the front side is set to 40 steps.

As described above, according to the present invention, the pressing member,
Film, heating element, or temperature near the edges of the film
The film shift speed is controlled according to the change in the film shift speed due to thermal changes (due to the friction coefficient between the transport roller and the film, the transport roller diameter), temperature distribution difference, and grease lubrication before and after running. Even if occurs, the shift speed of the film can be controlled in accordance with the temperature, and stable shift control can be performed.

[0092]

The present invention can easily implement the film deviation control means without complicating the structure and increasing the size thereof, and is an extremely effective means for long-term stable conveyance of a thin film.

[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 perspective view

FIG. 4 is a schematic configuration diagram of an example of an image forming apparatus using the heating device as a fixing device.

FIG. 5 is an outline drawing of an endless film.

FIG. 6 is a relationship diagram between a film sensor and a film position.

FIG. 7 is a graph showing a relationship between a film position and a film sensor output.

FIG. 8 is a schematic diagram of a control system.

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 of a film shift control program.
Chart

FIG. 13 is a flowchart of a film shift control program.
Chart

FIG. 14 is a side view of the device of the second embodiment.

FIG. 15 is a control flowchart of the apparatus according to the third embodiment.

FIG. 16 is a control flowchart of the device of the fourth embodiment.

[Explanation of symbols]

 Reference Signs List 11 endless film fixing sheet 12 driven roller 13 driving roller 14 fixing heater 15 pressure roller 16 photosensor 23 stepping motor 26 microcomputer 27 motor RTI, RT2 thermistor

Claims (4)

(57) [Claims] And 1. A shaped rotatable endless film,
A deviation control means for controlling the deviation of the film in the direction perpendicular to the moving direction of the film, to contact with the film
A pressure member, and the film and the pressure member
In an image heating apparatus for heating an image on a recording material by heat from the recording material bearing an image is nipped and conveyed the film side at the contact portion has a temperature detecting means for detecting a temperature of the pressure member, before
Serial image heating apparatus and controlling a deviation rate of the film by the shift control means in accordance with the detected temperature from the temperature detecting means. 2. A rotatable endless film,
A shift control unit for controlling the shift of the film in a direction orthogonal to the direction of movement of the film, and an image heating apparatus that heats an image on a recording material by heat from the film side; An image heating apparatus, comprising: a temperature detecting means for detecting a shift of the film by the shift controlling means in accordance with 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
Deviation control to control the deviation of the film in the direction perpendicular to the direction
Control means, and the heating element via the film
Image heating device that heats the image on the recording material
There are, have a temperature detecting means for detecting a temperature of said heating body, wherein
The deviation control means according to the temperature detected by the temperature detection means
You and controlling a deviation rate of the film by
Image heating device. 4. An endless rotatable film,
Of the film in a direction perpendicular to the moving direction of the film
Shift control means for controlling shift, and the film
Image heating device that heats the image on the recording material by heat from the side
In, have a temperature detecting means for detecting the temperature near both ends of the direction of the film orthogonal to the moving direction of the film, respectively
And an image heating device for controlling a shift speed of the film by the shift control unit in accordance with a difference between the detected temperatures from the temperature detection unit .