JPH03211141A - Shifting controller for turning endless film - Google Patents

Abstract

PURPOSE:To prevent an endless film from sustaining a damage by installing a mechanism, which selects a shifting direction of the endless film being installed in a winding means and turned and driven and performs its shifting control, and a fixed means which stores the shifting direction of the endless film, respectively. CONSTITUTION:A bearing 20 is shifted in the longitudinal directions of arrows A, B by an ON-OFF energizing current to a solenoid 23 whereby its film shifting control takes place. An endless film 11 first controls the solenoid 23 in conformity with the contents of a fixed random access memory (RAM) which stores the shifting direction controlled up to that time, since a motor 27 has turned. Next, when a sensor 16 is ON at the time of motor rotation, it waits to come to OFF and when it is off at that time, it waits to come to ON. After that it waits to come to OFF. A timing that output of a film that output of a film position sensor 16 is selected to OFF from ON is detected, setting the initial state, then a film position is detected from an OFF time till the sensor 16 is select to ON from OFF.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is a device for controlling the deviation of an endless film (endless belt body) which is suspended by a suspension means and is rotationally driven. The present invention relates to a device that prevents a film from shifting to one side or the other side in the width direction during a rotational movement process.

NFa+"g-1111 (prior art) For convenience, in image forming apparatuses such as copying machines and printers,
A fixing device that performs image fixing using a rotating endless film will be described as an example.

Various configurations and systems of fixing devices for image forming apparatuses are known and are in practical use.

Recently, a heating device (film heating method) has been devised that consists of a fixedly supported heating element, a film in contact with the heating element, and a pressure member that presses the recording material against the heating element through the film. There is.

The device disclosed in Japanese Patent Application Laid-Open No. 63-313182, which was previously proposed by the present applicant, belongs to this category, and the unfixed recording material is transferred through a thin heat-resistant film (sheet) that slides in pressure contact with a fixed heating element. It is a heating means/device that basically applies thermal energy to the toner image to soften and melt it, and then separate the film and recording material, or to separate the film and recording material after the toner has cooled and solidified.

This film heating type fixing device is different from other heat fixing devices such as heat roller type, hot plate type, flash fixing type, and oven fixing type because it can use a low heat capacity linear heating element. , it saves power, shortens wait time (quick start), and prevents offset because the fixing point and separation point can be set separately.
In addition, it has other advantages such as being able to solve various drawbacks of other types of devices, and is therefore effective.

The film can be of an endless type and can be rotatably driven and used repeatedly for fixing.
It is also possible to adopt an apparatus configuration in which a rolled film with an end is fed out and run for fixing.

In a fixing device using an endless type film, it is necessary to prevent the film from shifting (shifting) during the film rotation process. The causes of this positional shift are the parallelism of the rollers that suspend and stretch the endless film, and the parallelism of at least two endless film suspension and tension members.
However, there is a limit to how much accuracy can be improved, and it is extremely difficult to prevent the film from shifting by simply improving the accuracy.

Therefore, as a means of controlling the deviation of endless film,
At least one roller of the members on which the endless film is stretched is made into a crown shape, or flanges are attached to both ends of the roller to prevent the endless film from shifting.

(Problem to be solved by the invention) However, with such film bias regulating means,
If a thin heat-resistant sheet with a film thickness of less than 100μ is used, even if a crown roller or flange roller is used, the heat-resistant sheet as an endless film will not have elasticity, and because it is thin, wrinkles will occur in the heat-resistant sheet. Therefore, it was difficult to control the bias.

By displacing the roller shaft of at least one of the members on which the endless film is suspended,
By changing the degree of parallelism with other members to switch the shifting direction of the endless film, and at the same time providing a sensor that detects the position of the endless film and controlling the shifting, it is possible to regulate the shifting.

However, in this film shift control mechanism, when the film shift control starts immediately after the power is turned on, control is performed in a predetermined direction as an initial setting, so if there is a large speed difference depending on the film shift direction, the film shift control is In the time between detecting the initial film position and starting the actual shift control, the endless film may shift to either end, and in that case, not only will the endless film be damaged, but the fixing It also has the disadvantage of damaging the device.

For this purpose, there arises the drawback that the aforementioned tension adjustment of the endless film must be carried out with high accuracy in order to minimize the speed difference in the shifting direction.

The present invention aims to solve the above-mentioned problems when such a film shift control mechanism is adopted.

(Means for Solving the Problems) The present invention has a mechanism that performs shifting control by switching the shifting direction of an endless film stretched on a hanging means and rotationally driven, and which controls the shifting direction of the endless film. The object of the present invention is to provide a shift control device for a rotating endless film, which is characterized by having a non-volatile means for storing the information.

(Function) That is, with the configuration of the device described above, even in a case such as immediately after the power is turned on, it is possible to set the direction of the shift control at the same time as starting the shift control.

As a result, during the uncontrollable state from the start of control until the initial film position is detected and actual deviation control becomes possible, if the speed difference due to the deviation direction is large, the end of the endless film is This has the effect of preventing damage due to shifting and enabling reliable shifting control.

Of course, this makes it possible to prevent damage to the fixing device itself as in the above example, and at the same time, it is possible to control the shifting even if the speed difference depending on the direction of shifting of the endless film is large, so it is also possible to adjust the tension of the endless film. This also has the effect of eliminating the need for precision and increasing design margin.

(Example) <Example 1> Fig. 1 is a partially omitted plan view of an example of a fixing device using an endless film to which the film deviation control device according to the present invention is applied, Fig. 2 is a side view, and Fig. 3 is a partially omitted plan view. A schematic configuration of an example of an image forming apparatus incorporating this fixing device is shown.

(A) Configuration of Image Forming Apparatus The image forming apparatus shown in the example in FIG. 3 is an electrophotographic copying machine with a reciprocating document table, a rotating tram type, and a transfer type.The configuration, image forming process, etc. of this copying machine are known. Since it belongs to , I will only give a brief explanation.

Reference numeral 52 denotes a reciprocating document table glass disposed on the top plate 51 of the copying machine housing 50, and is driven to reciprocate in the left and right directions by a drive mechanism (not shown).

An original 53 is placed at a predetermined position on the second side of the original table glass 52 with the image side to be copied facing downward, and the original pressing plate 5
4 and set.

The downward image surface of the set original 53 is on the original platen glass 52.
The slit illumination scan is performed by sequentially passing through the illumination section 55 during the forward or backward movement process. 56 indicates an illumination light source.

Then, the downward reflected light of the original surface of the slit illumination light is sequentially imaged and exposed by an imaging lens (short focus imaging element array) 57 onto the surface of a photosensitive drum 58 which rotates in synchronization with the scanning of the original image.

The photosensitive drum 58 is charged positively or negatively by a discharger 59, and then subjected to the above-mentioned imaging exposure, so that an electrostatic latent image corresponding to the original image is sequentially formed on the drum circumferential surface. There is.

Next, the surface of the photosensitive drum 58 on which the latent images are formed sequentially passes through a developing device 60, and the latent images are sequentially developed.

The developed image on the surface of the photosensitive drum 58 reaches the transfer discharger 61 position.

On the other hand, the transfer material P is fed from the transfer material cassette 62 to the paper feed roller 6.
At step 3, one sheet is fed into the copying machine, and at that point, the leading end of the registration roller pair 64 is received in the nip portion of the registration roller pair 64, which is in a stopped state.

At a predetermined timing synchronized with the rotation of the photosensitive drum 58, rotation of the pair of registration rollers 64 is started, whereby the transfer material P is guided by the guide member and fed toward the photosensitive drum 58, and is exposed to the photosensitive drum 58. The developed image on the surface of the photosensitive drum 58 is sequentially transferred onto the transfer material P by introducing it into the transfer section between the drum 58 and the transfer discharger 61.

The copy material P on which the image has been transferred is sequentially separated from the surface of the photosensitive drum 58 by a separating means (not shown), is introduced into the fixing device 1 by the conveyance device 65, undergoes image fixation, and is delivered to the discharge roller as an image-formed product (copy). At 66, the paper is discharged to a paper discharge tray 67 outside the machine.

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

(B) Fixing device 1 In Figures 1 and 2, 13 and 12 are a pair of left and right endless film drive rollers that are arranged approximately parallel to each other, and a driven roller that also serves as a tension roller, and 11 is between these rollers 13 and 12. The drive roller 13 is rotated in the clockwise direction as shown by the arrow a by a drive system including a drive motor 27, so that it rotates at a predetermined circumferential speed in the clockwise direction shown by the arrow a. Driven.

Film 11 is a heat resistant film having a total thickness of 100μ, more preferably less than 40μ.

In this example, the endless film is made of a base film of polyimide, polyetherimide, PES-PFA, etc. with a thickness of about 20 microns, and a release layer of about 10 microns of PTFE or the like coated on the image contacting surface thereof.

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

Reference numeral 15 denotes a pressure roller having a rubber elastic layer with good mold releasability such as silicone rubber, and the film portion on the downward side of the endless film 11 is sandwiched between it and the heater 14 and is pressed by a biasing means (not shown), for example. They are brought into contact with each other with a total contact pressure of 4 to 5 kg, and as the film moves, they rotate forward in the film moving direction at a circumferential speed approximately concave to the film speed.

The transfer material P carrying an unfixed toner image t (heat-fusible toner) on its upper surface, which is transported from the transfer section 61 (FIG. 3) to the fixing device 1 by the transport device 65, is an endless film 11.
The film 11 and the pressure roller 1 of the pressure contact part (fixing nip part) N formed by the heater 14 and the pressure roller 15 with
5, the unfixed image surface is in a state of surface movement in the same direction as the transport speed of the transfer material P at approximately the same speed as the transfer material P. The surface of the film 11 is in close contact with the film 11, and the unfixed image surface is in the fixing nip in an overlapping state with the film 11. It passes through N while being subjected to a clamping force.

In this process, the toner image bearing surface of the transfer material P is heated by receiving heat from the heater 14 via the film 11, and at least the surface layer of the toner image t is completely softened and melted, and is thermally fixed to the surface of the transfer material P. .

The transfer material P that has passed through the fixing nip portion N is then separated from the surface of the film 11 by the curvature of the film 11 along the roller 13 when passing through the position of the film drive roller 13 .

(C) Film deviation control mechanism The driving roller 13 and driven roller 12 of the endless film 11 are disposed with bearings between the front side plate 19 and the rear side plate 18 of the fixing device 1, as shown in the first figure. It is. Reference numerals 21 and 20 denote a bearing on the front end side and a bearing on the rear end side of the driven roller 12.

Here, a driving roller 13, a driven roller 12, a heater 14,
Unless the accuracy of the parallelism (X-axis 2 direction, Y-axis direction, Z-axis direction) of the pressure roller 15 is set to ±0, the drive roller 13 is driven to rotate the film 11 in the direction of the arrow. As time goes by, this film 11 becomes the film shown by the solid line in FIG. 11 to the right or left in the film width direction,
The edge of the film will rub against the side plate 18 or 19 and be damaged.

Therefore, in this embodiment, the bearing 20 on the rear end side of the driven roller 12 is supported by the side plate 18 with a degree of freedom of movement in the front-rear direction of the arrow A-B, and is normally supported by the compression spring 22 in the forward direction A. The solenoid 23 is moved and energized to the first position shown by the solid line, where the receiver is stopped by a stopper (not shown), and the plunger of the solenoid 23 is connected to energize the solenoid.
N, the bearing 20 is pulled in the backward direction B against the compression spring 22 and displaced to the second position shown by the two-dot chain line.

That is, the degree of parallelism of the driven roller 12 with respect to the drive roller 13 and the heater 14 can be varied by turning ON/OFF the power supply to the solenoid 23.

In this example, when the solenoid 23 is OFF and the bearing 20 is in the first position shown by the solid line, the rotary film 11 moves over the suspension tension members 13, 12, and 14 along its length in the film width direction. When the solenoid 23 is turned on and the bearing 2o is in the second position shown by the two-dot chain line, the rotating film 11 moves to the left, that is, toward the far end of the rollers 13 and 12. Right side in the width direction, that is, rollers 13 and 12
It moves closer to the front end of the .

Reference numeral 16 denotes a photosensor that detects the shifting position of the film. In addition, as shown in FIG.
The masking process is applied as shown by diagonal lines to block the light.

In this embodiment, a photointerrupter is used as the photosensor 16, but if a reflective photosensor is used here, the end 3 portions of the film 11 need to be treated with a reflective material to reflect light. be.

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

Reference numeral 4 denotes a film edge cleaning member, which constantly cleans the film edge to prevent erroneous reading due to dirt or the like on the film edge when a reflective sensor is used, for example. Although felt is used in this embodiment, any type can be used as long as it has a cleaning effect.

FIG. 4 shows the external shape of the film 11. As mentioned above, this film is an endless belt, and its diameter is φM. Also, as shown in the figure, one end (the end on the near side) of the film 11 is cut diagonally, and the length of the longest part is Lmax, and the length of the shortest part is Lmin.
The dimension of the diagonally cut portion of the film 11 (diagonal cut portion) is determined by Lmax-Lmin, which is herein referred to as ΔL (film diagonal cut amount). This diagonal cut portion is placed on the front side of the main fixing device as shown in FIG.
is configured to detect the position of.

FIG. 5 is a detailed diagram of the positional relationship between the photosensor 16 and the film 11. In this embodiment, a transmission type photointerrupter is used as the photosensor 16, and its detection position is indicated by b. This means that when the film 11 is on the back side of the position b, the photosensor 16 is ON/OFF, and when it is on the near side of the position b, the photo sensor 16 is turned OFF.

Further, the diagonal cut portion of the film 11 is configured to be located at this detection position.

That is, as the film 11 rotates in the direction of the arrow a shown in FIG.
FF will be repeated, and the period ratio (duty ratio) of the 6 ON10 FF will vary depending on the film position (shift position).

The film position shown in FIG. 5 represents a reference position where the center of the diagonally cut portion of the film 11 is located at the detection position of the photosensor 16. The graph in FIG. 6 shows the relationship between the film position and the OFF time of the photosensor 16 with this film reference position as the center.

As shown in FIG. 6, when the film 11 is at the reference position, the OFF time of the photosensor 16 is 0 seconds, and when the film 11 is located at least ΔL/2 in front of the reference position, the OFF time of the photosensor 16 is 0 seconds. The OFF time of the photosensor 16 is 0 seconds.

Conversely, when the film 11 is located further back than the reference position by ΔL/2 or more, the photosensor 16 continues to be OFF.

Here, the position of the film 11 is such that the photosensor 16 is at 0.
FFL/The OFF time just before the continuing position is d seconds, which can be considered to be almost the same as the time for one rotation of the film 11, and the OFF time C seconds at the reference position is the OFF time at the diagonal cut part of the film. Since it is in the center, the O
The FF time is d seconds, which is about half the time.

(D) Film shift control circuit Next, FIG. 7 shows a schematic diagram of electrical control.

26 is a microcomputer whose input terminal IN
The photosensor 16 is connected to I. Also 0U
A solenoid 23 is connected to the TI terminal. 0UT
A rotation control signal for a motor 27 which also drives the main fixing device is output to the second terminal.

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

Although not shown, terminals for other human input signals and output signals of the copying machine using this fixing device are also provided, and the microcomputer 26 contains block programs such as sequence programs for the copying operation of this copying machine. In addition to the ROM and RAM, the memory contents are retained even if the power supply to the microcomputer 26 is cut off.
Built-in AM.

8 to 11 show flowcharts of the film deviation control program of the present fixing device.

This program is also programmed in the built-in ROM in the microcomputer 26, and is called and executed from the main sequence program or the like at fixed time intervals or as needed.

First, after the start, in step 1 (FIG. 8), it is determined whether the motor 27 is ONL.

If the motor 27 is ONL, step 2
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 far to move toward the front side. This is the non-volatile RAM in the microcomputer 26 mentioned above.
The contents of the predetermined address above are set as the near side flag, and when the state of the memory is 1, that is, when the control has been on the near side so far, the process moves to step 3 and the solenoid 23 is turned ON/OFF.
The shift control is set to the front side and the process moves to step 4. If the near side flag is 0 in step 2, the film has been controlled so far to move toward the back side, so the process directly proceeds to step 4.

In step 4, it is determined whether the sensor 16 is OFF or not. If the sensor 16 is ON, the process moves to step 8, and if it is OFF, the process moves to step 5.

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

In step 6, it is determined whether or not the sensor 16 is on, and if it is not on, the process moves to step 7.

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

0 Here, the contents of the error check routine will be explained based on FIG. 10. First, in step S1, the motor 27
is ON or not, and if it is ON, the process moves to step S2, and if it is not ON, the process goes to step S13 (
9).

In step S2, it is determined whether the error timer value is greater than d seconds, and if it is smaller, the process moves to the exit of this routine. If the error timer value is greater than d seconds in step S2, the process moves to step S3.

In step S3, an error flag is set and the process moves to the exit of this routine.

Next, in step 6, if the sensor 16 is ON, the process moves to step 8, where the value of the error timer is reset to 0, measurement is started, and the process moves to step 9.

In step 9, it is determined whether the sensor 16 is OFF or not. If it is not OFF, the process moves to step 10, executes an error check routine, and returns to step 9. If the sensor 16 is OFF, the process moves to step 11. Then, the value of timer 1 is reset to 0, measurement is started, and the process moves to step 12 (FIG. 9).

In step 12, it is determined whether or not the motor 27 is on, and if it is on, the process moves to step 14.

In step 14, it is determined whether the sensor 16 is ON or not. If it is not ON, the process moves to step 15, executes an error check routine, and returns to step 14.
If it is ON, the process moves to step 16.

In step 16, a comparison is made to see if the measured value of the timer 1 is smaller than d/4 seconds, and if it is smaller, it can be determined that the film 11 is located on the front side. For,
Proceeding to step 17, the solenoid 23 is switched to 0FFL/the film 11 shifting direction to the rear side, the front flag is reset to 0, and the process proceeds to step 2o.

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

In step 18, a comparison is made to see if the measured value of timer 1 is greater than 3d/4 seconds, and if it is not, the process moves to step 20, and if it is, film 1
Since it can be determined that the film 1 is located on the back side, the process moves to step 19, turns on the solenoid 23, switches the shifting direction of the film 11 to the front side, sets the front flag to 1, and moves to step 20.

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

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

If the sensor 16 is OFF in step 21, the process moves to step 23, where the value of the timer 13 is reset to 0 and measurement is started, and the process returns to step 12.

If the motor 27 is OFF in step 12, the process moves to step 13, where the timer 1 stops measuring, the measured value is reset to 0, and then the solenoid 2 is turned off.
3 will be turned OFF and the process will return to step 1.

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

If the error flag is set in step 24, the process moves to step 25, where all outputs of all devices (in this example, the copying machine) are turned off, and then the process moves to step 26, where a film abnormality display is displayed. The execution step 26 is set as an endless loop so that the main program cannot be executed.

As described above, when the motor rotates, the endless film 11 of the present fixing device first controls the solenoid 23 according to the contents of the non-volatile RAM that stores the shifting direction that was previously controlled. Next, if the sensor 16 is ON when the motor is rotating, wait until it turns OFF.
If the sensor 16 is OFF, it waits until it turns ON and then turns OFF, and the timing at which the output of the film position sensor 16 switches from ON to OFF is detected and the initial setting is completed. And then sensor 1
O of sensor 16 until 6 switches from OFF to ON
The position of the film 11 is detected only after measuring the FF time.

In other words, the control of the film 11 is disabled until this first measurement of the OFF time of the sensor 16, so by setting the film 11 in the direction in which it was being controlled before then, the above-mentioned uncontrollable state can be avoided. This prevents the film from abnormally shifting to either end. Thereafter, from the timing when the sensor 16 switches from ON to OFF, until the sensor 16 switches from OFF to ON.
The OFF time of the film is measured and the film position is controlled to be within a predetermined control range.

Further, in this embodiment, a transmission type photosensor is used as the sensor 16, but it goes without saying that the same effect may be obtained by using a sensor such as a microswitch or a reflection type photosensor.

<Embodiment 2> FIG. 12 shows a schematic diagram of electrical control of a second embodiment of the present invention, and the other configuration is the same as that of the above-mentioned embodiment 1. 28 is a microcomputer; Input terminal IN
A photosensor 1 that detects the position of the film 11 on I
6 is connected. Further, a solenoid 23 is connected to the 0UT1 terminal.

The 0UT2 terminal is connected to the 0UT2 terminal, which also drives the main fixing device.
The number of rotation control signals No. 7 is outputted is the same as that shown in FIG. 7 of the first embodiment.

A +5V power supply is connected to the VDD terminal, and at the same time, a battery 30 is also connected via a diode 29.

Further, the GND terminal is connected to ground.

Although not shown, it is equipped with terminals for other input signals and human input signals of the copying machine using this fixing device, and the microcomputer 28 is programmed with a sequence program for the copying operation of this copying machine. It has a built-in ROM and RAM, but it does not have a built-in non-volatile RAM whose memory contents will not be erased even if the power supply is cut off.

However, even if the +5V power supply is cut off, the aforementioned battery 30
Since the power is supplied from the microcomputer 28
It is possible for the contents of the RAM within the device to remain intact. Therefore, it goes without saying that the same operation as in the first embodiment is possible and the same effects can be obtained.

<Example 3> A third embodiment is shown in FIGS. 13 to 16.

The configuration of this embodiment is the same as that of the first embodiment, but the solenoid 2
3 is replaced with a monostable latching solenoid 31.

FIG. 13 shows a schematic diagram of the electrical control.

First, 32 is a microcomputer, and a photosensor 16 for detecting the position of the film 11 is connected to its input terminal INI.

Further, the 0UTI terminal and the 0UT2 terminal are connected to a monostable latching solenoid 31 (hereinafter referred to as a latching solenoid). This is because the latching solenoid used in this example is of a two-winding type, and the suction side winding is zero.
It is connected to the UT1 terminal, and the release side winding is connected to the 0UT2 terminal. A rotation control signal for a motor 27 that also drives the fixing device is output to the 0UT3 terminal.

A +5v power supply is connected to the VDD terminal, and the GND terminal is connected to the ground.

8 Although not shown, terminals for other manual signals and output signals of the copying machine using this fixing device are provided, and the microcomputer 32 is programmed with a sequence program for the copying operation of this copying machine. Built-in ROM, RAM, etc.

To explain the latching solenoid 31 here, this solenoid has a built-in permanent magnet, and when the plunger is pulled by applying voltage to the attraction side winding, the plunger is held by the permanent magnet. Therefore, there is no need to apply voltage to the suction side winding.

Furthermore, when a voltage is applied to the release side winding, a magnetic force is generated to cancel the magnetic force of the permanent magnet, so that the attraction is released by the action of the compression spring 22 as shown in FIG. In this case as well, it is unnecessary to apply voltage to the release side winding after release. From this, it is sufficient to apply a pulse voltage to each winding of the latching solenoid, and in this embodiment, a pulse voltage with a pulse width of 100 m5 is applied.

14 to 16 show flowcharts of the film deviation control program of this embodiment.

This program is also programmed in the built-in ROM in the microcomputer 32, and is called and executed from the main sequence program or the like at fixed time intervals or as needed.

First, after starting, in step 101 (FIG. 14), it is determined whether the motor 27 is ONL.

If the motor 27 is ON, step 10
4, and if the motor 27 is OFF, step 10
1 and waits until the motor 27 is turned on.

Next, in step 104, it is determined whether the sensor 16 is ON or not. If the sensor 16 is OFF, the process moves to step 108, and if it is ON, the process moves to step 105.

In step 105, the value of the error timer is reset to 0, measurement is started, and the process moves to step 106.

In step 106, it is determined whether or not the sensor 16 is on. If it is not on, the process moves to step 107.

In step 107, an error check routine is executed and the process returns to step 106.

Here, the contents of the error check routine will be explained based on FIG. 16. First, in step 5101, it is determined whether or not the motor 27 is ON. If it is ON, the process moves to step 5102, and if it is not ON, the process moves to step 5102. Then the process moves to step 113 (FIG. 15).

In step 5102, it is determined whether the error timer value is greater than d seconds, and if it is smaller, the process moves to the exit of this routine.

If the error timer value is greater than 5 seconds in step 5102, the process moves to step 5103.

In step 5103, an error flag is set and the routine moves to exit [1].

1 Next, in step 106 (FIG. 14), the sensor 16
If it is ON, proceed to step 108, reset the error timer value to 0, start measurement, and proceed to step 1.
Move to 09.

In step 109, it is determined whether or not the sensor 16 is OFF. If it is not OFF, the process moves to step 110 and an error check routine is executed, and step 109
Return to Step 1 if the sensor 16 is turned off.
11, the value of timer 1 is reset to O, measurement is started, and the process moves to step 112 (FIG. 15).

In step 112, it is determined whether or not the motor 27 is on. If it is on, the process moves to step 114.

In step 114, it is determined whether the sensor 16 is ON or not. If it is not ON, the process moves to step 115 to execute an error check routine and returns to step 114. If it is ON, the process moves to step 116.

In step 116, a comparison is made to see if the measured value of timer 1 is smaller than 2 d/4 seconds, and if it is smaller, it is determined that the film 11 is located on the front side, so the process moves to step 117. Solenoid 31
The suction release drive signal is output, the direction of shifting of the film 11 is switched to the back side, and the process moves to step 120.

Also, in step 116, whether the measured value of timer 1 is d/4
If it is not smaller than seconds, the process moves to step 118.

In step 118, a comparison is made to see if the measured value of timer 1 is greater than 3d/4 seconds, and if it is not, the process moves to step 120, and if it is greater, it is determined that the film 11 is located on the back side. Because it is possible, step 11
9, output a suction drive signal for the solenoid 32, change the direction of shifting of the film 11 to the front side, and step 12.
Transition to 0.

In step 120, the value of the error timer is reset to 0 and measurement is started, and the process moves to step 121.

In step 121, it is determined whether the sensor 16 is OFF or not. If it is not OFF, the process moves to step 122 and an error check routine is executed.
Return to 21.

See you at step 12! If the sensor 16 is OFF, the process moves to step 123, where the value of the timer 1 is reset to 0 and measurement is started, and the process returns to step 112.

If the motor 27 is OFF in step 112, the process moves to step 113, where the timer 1 stops measuring, resets the measured value to 0, and returns to step 101 (
This will return to Figure 14).

It should be noted that the film abnormality processing program, which is a part of the main program, is the same as that in the first embodiment described above, so a description thereof will be omitted here.

As explained above, the sensor 16 is ON when the motor is rotating.
If so, wait until the sensor 16 turns OFF, and then turn the sensor 16 OFF again.
In the case of F, wait until it turns ON and then wait until it turns OFF, so that the output of the fill person position sensor 16 turns ON.
The initial setting is completed by detecting the timing of switching from to OFF. Then, the position of the film 11 is detected only after measuring the OFF time of the sensor 16 until the sensor 16 is switched from OFF to ON.

In other words, the control of the film 11 is disabled until this first measurement of the OFF time of the sensor 16, but since the latching solenoid 32 is set in the direction in which it was previously controlled, the above-mentioned This prevents the film from shifting abnormally to either end during uncontrolled conditions. Thereafter, the OFF time of the sensor 16 is measured from the timing when the sensor 16 is switched from ON to OFF, and the film position is controlled to be within a predetermined control range. Furthermore, by using a latching solenoid, it is only necessary to apply a pulsed voltage to the ON10 FF of the solenoid, resulting in an energy saving effect.

(Effects of the Invention) As explained above, the shifting control of a rotating endless film has a mechanism that performs shifting control by switching the shifting direction of the endless film, and has a nonvolatile means for memorizing the shifting direction of the endless film. The device makes it possible to set the direction of shift control that was previously used at the same time as the shift control starts, even in cases such as immediately after the power is turned on.

As a result, during the uncontrollable state from when the initial film position is detected to the time when the actual film position control becomes possible, if there is a large speed difference depending on the direction of the film, the endless film moves in either direction in the width direction. This has the effect of preventing damage from occurring near the edges.

Of course, this makes it possible to prevent damage to the fixing device using endless film as in the above example, and at the same time, it is possible to control the shifting of the endless film even if there is a large speed difference depending on the shifting direction of the endless film. Precision is no longer required for tension adjustment, and there is also the effect of increasing design margin.

Therefore, by applying the present invention to a fixing device such as the one described above using an endless film, it is possible to greatly improve the reliability and practicality of this type of fixing device.

[Brief explanation of drawings]

FIG. 1 is a partially omitted plan view of an example of a fixing device to which a film deviation control device according to the present invention is applied. Figure 2 is its side view. FIG. 3 is a schematic configuration diagram of an example of an image forming apparatus. Figure 4 shows the outline of the endless film. FIG. 5 is a diagram showing the relationship between the film sensor and the film position. FIG. 6 is a graph showing the relationship between film position and film sensor output. FIG. 7 is a schematic diagram of electrical control in the first embodiment. 8 to 11 are flowcharts of the shift control program of the first embodiment. FIG. 12 is a schematic diagram of electrical control of the second embodiment. FIG. 13 is a schematic diagram of electrical control of the third embodiment. 14 to 16 are flowcharts of the shift control program of the third embodiment. 11 is an endless film fixing sheet, 12 is a driven roller, 13 is a driving roller, 14 is a fixing heater, 15 is a pressure roller, 16 is a photosensor 23 is a solenoid, 26.
28 and 32 are microcomputers, 27 is a motor, 3
0 is a battery, 31 is a monostable latching solenoid.

Claims (1)

[Claims] (1) It has a mechanism for controlling the shifting by switching the shifting direction of the endless film that is stretched on the hanging means and is rotationally driven, and has a non-volatile means for memorizing the shifting direction of the endless film. A rotating endless film shift control device featuring: