JPH0569979A - Control device for snaking of belt - Google Patents

Abstract

PURPOSE:To provide a device with which snaking of a belt is controlled in simple constitution so as to stably run the belt. CONSTITUTION:An endless belt 22 is tensely mounted between at least two rollers 23, 24, one is a drive roller 23, the other is an oscillatable driven roller 24, and torque of a drive motor 26 to drive the rotation of the drive roller 23 is transmitted through a spring clutch 27 as a transmission control means, by rotating an operation member 31 to move according to deviation of the belt 22. A control device for snaking of the belt is constituted so that an oscillating lever 33 is rotated by the rotation transmitted, the oscillatable driven roller is oscillated in the direction of moving the belt 22 on the reverse side of the deviation direction of the belt 22, and hereby snaking of the belt 22 can be controlled. Consequently, the drive motor 26 to drive the drive roller 23 can be utilized as it is for controlling snaking of the belt 22, and miniaturization and cost down can be attained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoreceptor belt having a photosensitive layer for forming an image, a transfer belt for transferring a toner image formed on the photoreceptor, and a toner image in an image forming apparatus or the like. The present invention relates to a device that stabilizes the running of a belt by performing a meandering control of the belt such as a heat resistant belt for fixing the toner.

[0002]

2. Description of the Related Art In an image forming apparatus adopting an electrophotographic system, a photosensitive member travels in one direction at a constant speed (rotation / movement).
Then, by exposing the optical information, an electrostatic latent image corresponding to the optical information is formed on the surface thereof. Here, as the photosensitive member, there are one that rotates a cylindrical drum, one that runs a sheet-shaped endless belt, and the like.

In the case of the above cylindrical drum, there is no problem when it is rotationally driven with the center axis of the drum as a rotation axis, but when a belt-shaped photosensitive member is run, a problem of meandering occurs, and the meandering is caused. If it is left as it is, a normal image cannot be formed, and problems such as image distortion occur.

Therefore, a belt meandering control device as disclosed in Japanese Patent Laid-Open No. 54-69442 has been proposed. This meandering control device stretches a belt between driving and driven rollers, and installs a swingable swinging roller that is in contact with the inner surface of the belt at a substantially middle portion of the belt, and detects deviation of the belts arranged at both ends of the belt. The swing roller is swung in any direction (the shaft is tilted) according to a signal from the detecting means.

With the above structure, the belt is stably run, and in response to the detection of the deviation of the belt to one side, the swing roller is tilted in one direction with respect to the rotation axis so that the belt is biased to the other side. Drive to control the belt meandering.

[0006]

In the conventional belt meandering control device, position detecting means at both ends of the belt, driving means for swinging the swinging roller in either direction, and controlling the means. A control unit and the like are required, and the cost is increased due to an increase in the number of parts and an increase in the size of the device.

Further, since the conventional apparatus becomes large in size, it cannot be applied as it is to a small fixing apparatus using a heat resistant belt.

The present invention provides a meandering control device having a very simple structure by reducing the number of parts in order to solve the above-mentioned conventional drawbacks.

The present invention also provides a device which can be used also as a belt meandering control in a fixing device.

[0010]

According to the belt meandering control device of the present invention, an endless belt is stretched between at least two rollers, and the rollers are rotated to drive and drive the belt. A drive source for driving the rotation drive roller, wherein the rotation roller is provided separately from the rotation roller, and the wobble roller is rocked as necessary to control the meandering. It is characterized in that the rotating roller is swung in response to the deviation of the belt by utilizing the rotational force of.

Particularly, in the belt meandering control device of the present invention, since the rotational force of the drive source for rotationally driving the drive roller is utilized, the rotational force of the drive source is transmitted in response to the deviation of the belt in one direction. It is characterized in that a transmission means for enabling the movement is provided and the rocking roller is swung by the rotation transmitted by the transmission means to control the meandering of the belt.

Further, the transmission means is characterized in that a rotational force is transmitted by a spring clutch to swing the swing roller.

[0013]

According to the belt meandering control device of the present invention, the endless photosensitive belt or the heat-resistant belt of the fixing device is driven in one direction by the driving roller being driven by the rotational force of the driving source. .. If the belt is biased in any direction while the belt is running, the rocking roller is rocked by utilizing the rotational force of the drive source that drives the drive roller in response to the bias. That is, the rocking roller is tilted so as to move the belt in the direction opposite to the one-sided direction. As a result, the running belt moves in the opposite direction and the meandering is controlled.

In particular, the transmission means for transmitting or not transmitting the rotational force in order to swing the swing roller in either direction by the rotational force from the drive source of the drive roller when the belt is deviated. For example, a spring clutch is used, and the operating member that responds to the deviation of the belt is operated by this spring clutch, and the rotational force from the drive source is transmitted as it is. That is, if the belt is biased in either direction, the rotational force from the drive source is transmitted by the spring clutch. For example, the swing control means that rotates by this rotation is
The oscillating roller is oscillated so as to incline the biased belt to the opposite side.

By using the spring clutch as the transmission means, the rotational force of the drive source can be transmitted to the rocking roller via the means that mechanically responds to the deviation of the belt, and the structure can be made very simple and the cost etc. can be reduced. Can be reduced.

[0016]

FIG. 1 is a side view showing a belt meandering control device according to the present invention, and this embodiment shows a heat fixing device. FIG. 2 is a top view of the belt meandering control device according to the present invention of FIG. 1 as viewed from above. 3 and 4 are side and top views corresponding to FIGS. 1 and 2 for explaining the operation of the meandering control of the present invention, and FIG. 5 is an electronic device using the belt meandering prevention device of the present invention as a fixing device. It is a cross-sectional view showing the overall configuration of an optical printer according to the photographic method.

In FIG. 5, 1 is a photosensitive drum, 2 is a charging device (charging roller), 3 is an LED array, 4 is a developing device,
Reference numeral 5 is a transfer device (transfer roller), 6 is a cleaner, 7 is a paper feeding device, 8 is a paper feeding tray, 9 is a fixing device, 10 is a paper ejection tray, and 11 and 12 are paper detection switches. First, the surface of the photosensitive drum 1 is uniformly charged by the charger 2 in a dark place. Next, the LED array 3 exposes the image pattern to remove the charged electric charge in the exposed portion to form an electrostatic latent image. In the developing device 4, a toner having the same polarity as the charged charges on the photoconductor drum 1 is attached to the portion from which the charged charges have been removed to form a visible image (reverse development). Then, the transfer paper 13 is superposed on this visible image, and a voltage having a polarity opposite to that of the toner is applied from the back side of the transfer paper 13 by the transfer device 5 to electrostatically attract the toner image on the surface of the photoreceptor 1 to transfer the transfer paper 13. Transfer to. The transferred toner image is fixed on the transfer paper by the fixing device 9.

As shown in FIGS. 1 and 2, the fixing device 9 has an endless heat-resistant belt 22 made of, for example, a polyimide resin-based film stretched between a driving roller 23 and a driven roller 24. And a pressure roller 25 that is appropriately pressed against the pressure roller 25.
The heating member 21 is provided so as to come into pressure contact with the inner surface of the belt 22 in the portion facing the. The heating device 20 includes a heating member 21 made of, for example, a ceramic heater, and a heat insulating material 19 that holds the heating member 21 and thermally shields at least the opposite surface that contacts the belt 22. This heating device 2
0 is a heat insulating material 19 fixed to a mounting plate (not shown) fixed to a frame (not shown) of the printer main body,
The pressure roller 25 is pressed against the heat resistant belt 22.

According to the fixing device 9 having the above-described structure, when the transfer paper 13 carrying the transferred toner image is conveyed from the right side in the figure to the contact point between the heat resistant belt 22 and the pressure roller 25, the heat resistant belt is formed. Since 22 is driven in the direction of the arrow by the drive roller 23, the pressure roller 25 is driven according to the movement of the heat resistant belt 22, and therefore the transfer paper 13 is conveyed while being pinched on the left side in the drawing. Since the heat-resistant belt has a thin thickness of about 30 μm and a small heat capacity, the heat generated by the heating member 21 is instantly transferred to the transfer paper 13 to melt and fix the toner. A feature of this fixing method is that the waiting time during warm-up is shorter than that of the conventional heat roller fixing method. That is, by driving the heating member 21 immediately before the transfer paper 13 is sent to the fixing device 9, sufficient fixing can be performed.

Next, the meandering control device for the heat resistant belt 2 will be described. In FIG. 1, a driven roller 24 is a swinging roller that is swingably provided to control meandering, and a rotation shaft 24a is rotatably supported by both frames (not shown). In order to make the driven roller 24 swingable in the vertical direction in FIG. 1, for example, the back side of the rotating shaft 24a is rotatably held in a fixed position on the frame, and the driven roller 24 is mounted on the front side frame. It is rotatably supported so that it can move up and down.

In the driven roller 24, one end of a rotary shaft 24a is connected to an L-shaped rocking lever 33, and the rocking lever 33 is not shown so as to be rotatable around the shaft 33a. It is supported by one frame on the front side.
Therefore, the driven roller 24 swings when the swing lever 33 rotates and the rotation shaft 24a moves up and down, and tilts with respect to the shaft of the drive roller 23.

On the other hand, in order to control the meandering of the heat resistant belt 22, an actuating member 31 provided so as to be in contact with one end of the heat resistant belt 22 is rotatably provided. The actuating member 1 is rotatably provided around the shaft portion 31a, and normally the heat resistant belt 2 is urged by the urging force of the spring 32.
The contact piece 31b is rotated so as to contact the one side end of the No. 2 side. The rotation control piece 31c on the opposite side of the contact piece 31b of the actuating member 31 is arranged so as to face the sleeve 30 that constitutes the spring clutch 27, which is a transmission means for transmitting or non-transmitting the rotational force. ..

As clearly shown in FIG. 2, the spring clutch 27 protrudes from the outer peripheral surface of the sleeve 30 and has a pawl 30a.
And 30b are formed, and the claws 30a and 30b are formed so as to deviate by 180 ° in terms of rotational angle and also deviate in the axial direction. Therefore, the rotation control piece 31c of the operating member 31 is connected to the claw 30 of the sleeve 30.
The heat-resistant belt 22 moves in response to the one side of the heat resistant belt 22 so as to face the a or 30b.

The spring clutch 27 transmits the rotation of the input side, that is, the rotation of the input section 28 to which the rotational force of the drive motor 26 for rotationally driving the drive roller 23 is transmitted, to the output section 29. .. That is, the rotation control piece 31c of the operating member 31 is attached to the claw 30a of the sleeve 30.
However, in the locked state, the rotation of the input unit 28 is not transmitted to the output unit 29, and the rotation control piece 31c is not connected to the claw 30a.
When it is disengaged (moved upward in FIG. 2), it is transmitted to the output unit 29, and when it is rotated 180 ° (half rotation), the pawl 30b is locked to the rotation control piece 31c to transmit the rotation. Be stopped.

As shown in detail in FIG. 8, the spring clutch 27 is rotatably supported by a fixed shaft 27a fixed to a frame or the like.
8 and an output part 29 are provided, and a spring 40 is wound around both peripheral surfaces of the boz part 28b of the input part and the boz part 29b of the output part, which are integrally formed with them, and around the spring 40. The sleeve 30 is arranged in the above. Each of the boss portions 28b and 29b is a separate body, and is formed so that the outer diameters thereof are substantially the same. The spring 40 is wound around both the boss portions 28b and 29b in a state where the winding direction is set so that the inner diameter is contracted by the rotation of the input portion 28, and one end of the spring 40 is locked to the output portion 29 and the other end. Is locked to the sleeve 30.

Due to the above structure, the sleeve 30
Is not locked by the rotation control piece 31c and its rotation is not restricted, the spring 40 rotates the input portion 28, so that the spring 40 causes the boss portions 28b and 29b of the input portion and the output portion.
The rotation of the input unit 28 is transmitted to the output unit 29. On the other hand, if the rotation of the sleeve 30 is restricted, even if the input portion 28 rotates, the spring 40 loosens without wrapping around the boss portions 28b and 29b, so that the rotation is transmitted to the output portion 29. It becomes a state. for that reason,
The rotation control piece 31c for restricting the rotation of the sleeve 30 has the claw 3
When the rotation of the sleeve 30 is unrestricted without being locked to 0a or 30b, the sleeve 30 rotates at the same time as the rotation of the input portion 28, transmits the rotation of the output portion 29, and the claw 30a
Alternatively, if the rotation control piece 31c is locked to 30b to restrict the rotation, the rotation is not transmitted to the output unit 29.

A sprocket or a gear 28a, for example, through which the rotational force of the drive motor 26 for rotationally driving the drive roller 23 is transmitted via a transmission mechanism such as a churn or a gear (gear), is fixed to the input section 28. The drive motor 26 rotates to rotate around the fixed shaft 27a. At this time, the heat resistant belt 22 is also rotated at the same time.

The spring clutch 27 transmits or does not transmit rotation from the input portion 28 rotated by the drive motor 26 to the output portion 29. Therefore, an eccentric cam 41 for rotating a swing lever 33 for swinging the driven roller 24 for controlling the meandering of the heat resistant belt 22 around the shaft portion 33a is fixed to the output portion 29. There is. The eccentric cam 41 is rotated about the fixed shaft 27a, and the longest diameter surface from the shaft 27a is the swing lever when the rotation control piece 31c is locked to the claw 30a of the sleeve 30 as shown in FIG. When the rotation control piece 31c is in contact with the claw 30b and the pawl 30b, the minimum diameter surface is in contact with the swing lever 33. In particular, the swing lever 33 is always urged to rotate counterclockwise in FIG. 1 by the spring 34 so as to always contact the peripheral surface of the eccentric cam 41.

The belt meandering control device is configured as described above, and its operation will be described below with reference to FIGS. 1 to 4, 6 and 7.

As shown in FIG. 2, when the heat resistant belt 22 is running at the position of arrow A, the rotation control piece 31c of the actuating member 31 of the sleeve 30 constituting the spring clutch 27. Since it is locked to the claw 30a, the rotation from the input unit 28 is not transmitted to the output unit 29. At this time, the swing lever 33 is pushed against the spring 34 by the longest diameter surface of the eccentric cam 41 and is rotated clockwise, as clearly shown in FIG. Therefore, the driven roller 2 whose one end is connected to the swing lever 33
4, the driven shaft 24 is lifted upward and the driven roller 24 is tilted upward in FIG.
The side to which is connected is inclined upward from the back surface).
In this state, the heat resistant belt 22 is run by the rotation of the drive roller 23.

When the driven roller 24 is tilted upward, the heat-resistant belt 22 runs, so that the heat-resistant belt 22 gradually starts to shift to the position shown by the arrow B. That is, as shown in FIG. 6 which is a schematic view of the driven roller 24 viewed from the right side in FIG. 1, the heat resistant belt 22 is run along the peripheral surface of the driven roller 24 in the direction of arrow D. Since the driven roller 24 is inclined downward to the right as shown in FIG.
Looking at the point a at which the belt 22 and the driven roller 24 do not come in close contact with each other, the point a becomes the point b when the belt 22 runs and the belt 22 and the driven roller 24 start to separate from each other. Moving. By performing this continuously, the belt 22 gradually moves in the direction of arrow E downward in FIG.

By moving the heat-resistant belt 22 downward in FIG. 2, the contact piece 31 is formed at one end of the belt 22.
b is pushed, and the operating member 31 is rotated counterclockwise about the shaft 31a. Therefore, the rotation control piece 31c moves upward, the heat-resistant belt 22 moves to the position of the arrow B, and travels, so that the rotation control piece 31c moves from the claw 30a of the sleeve 30 of the spring clutch 27 as shown in FIG. It comes off and moves to a position corresponding to the claw 30b. Thereby, the rotation of the spring clutch 27 can be transmitted, and the rotation of the input unit 28 is transmitted to the output unit 29. As a result, the eccentric cam 41 is rotated, and the minimum diameter surface of the eccentric cam 41 faces the swing lever 33. In this state, the claw 30b of the sleeve 30 is locked to the rotation control piece 31c, the rotation transmission to the output unit 29 is stopped, and the position is maintained.

In the above-described state, the driven roller 24 connected to the swing lever 33 is pushed downward on the front side as shown in FIG. 3, and the driven roller 24 is moved downward (downward in FIG. 4). (The shaft end of is below the shaft end of the back)
Tilt to. As shown in FIG. 7 which is a schematic view of the driven roller 24 portion when viewed from the right side of FIG. 4, the point c at which the belt 22 and the driven roller 24 start contacting each other is the belt along the driven roller inclined upward to the right. Is driven, the belt 22 moves to a point d where the belt 22 starts to separate from the driven roller. By continuing this, the heat-resistant belt 22 moves in the direction of arrow F and upward in FIG. 4, contrary to FIG.

By repeating the above operation, the meandering of the heat resistant belt 22 can be controlled and the belt can be stably run.

According to the present embodiment, the meandering control of the endless belt in the fixing device has been described, but the present invention is not limited to this device. For example, in the case where the photoconductor is configured in a belt shape, the photoconductor belt is stretched between at least the driving roller and the driven roller, and the driven roller is shown in FIG.
This can be implemented by using the same structure as the meandering control device as shown in FIG. Further, in the case where the toner image formed on the photoconductor is once transferred to an intermediate intermediate transfer medium and then retransferred to a member such as paper, the same applies to a belt-shaped intermediate transfer medium. Can be carried out.

Moreover, in FIG. 1, the heat resistant belt 22 is stretched between the two rollers 23 and 24, but the number of rollers is not limited to two and the belt may be driven by more rollers. The present invention can be applied.

Further, according to the embodiment of the present invention, as a structure for swingably supporting the driven roller 24, the rotation shaft 24a of the driven roller 24 of the swing lever 33 is connected to the swing roller 33 so that the driven roller 24 can swing. It uses the rotation to move up and down. In this case, the rotation shaft 24a of the driven roller 24 holds the end portion on the side opposite to the side connected to the swing lever 33 at a fixed position. Therefore, the rotating shaft 24a is rotatably supported by a frame (not shown) on the side held at the fixed position, and the end of the rotating shaft connected to the swing lever 33 is attached to the swing lever 3.
It may be rotatably held at 3. As a result, the driven roller 24 can be swung with respect to the drive roller 23 so that the rotation shaft is inclined in any direction.

Not limited to this, the rotation lever 2 is attached to the swing lever 33.
4a is urged by a spring or the like so that the rotary shaft 24a of the driven roller 24 is always in contact with the rocking lever 33 so as to maintain the contact relationship without connecting the one end of 4a so as to rotatably support it. Alternatively, the driven roller 24 may be moved up and down by the rotation of the swing lever 33. In this case, the side of the rotary shaft 24a of the driven roller 24 corresponding to the swing lever 33 is rotatably held in the frame via the bearing, and the bearing is moved (slide) in the vertical direction with respect to the frame. It should be provided. In particular, a long hole is formed in the frame to move the bearing up and down, and the frame moves within the long hole. Then, the rotation shaft 24a, which contacts the swing lever 33, may be moved in the up-down direction by the rotation of the swing lever 33 against the spring.

Further, a support member rotatably supporting both ends of the rotary shaft 24a of the driven roller 24 is provided, and the support member is, for example, clockwise or counterclockwise around the central portion (position near the point a) in FIG. It is configured to be held rotatably in a clockwise direction, and in a normal state, a rotational biasing force is applied to the rocking lever 33 so that the shaft 24a contacts the rocking lever 33.
The driven roller 34 may be vertically swung by the rotation of 3.

[0040]

As described above, the apparatus of the present invention requires means for detecting deviation of the belt, means for swinging the roller for preventing belt meandering in response to the detection of the detecting means, and the like. Without using the drive source, the belt driving source can be used as it is to control the belt meandering by a simple means, and the belt can be run in a stable state, and the size can be reduced by reducing the number of parts. The cost can be reduced.

In particular, it can be applied to a fixing device using a belt.

[Brief description of drawings]

FIG. 1 is a side view showing an example of an apparatus for controlling the meandering of a belt according to the present invention.

2 is a top view of the device according to the invention in FIG.

3 is a side view for explaining an operation in reverse meandering control of a belt in the apparatus of FIG.

FIG. 4 is a top view showing a state in which FIG. 3 is viewed from above.

FIG. 5 is a side sectional view showing a state where the belt meandering control device according to the present invention is applied to a fixing unit of an electrophotographic printer.

FIG. 6 is a diagram for explaining the operation of the meandering control according to the present invention.
Schematic diagram of the driven roller section seen from the right side of the

FIG. 7 is a diagram illustrating an operation of meandering control according to the present invention.
Schematic diagram of the driven roller section seen from the right side of the

FIG. 8 is a cross-sectional view showing an example of a spring clutch that constitutes a rotational force transmitting means according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor 9 Fixing device 22 Heat resistant belt 23 Drive roller 24 Driven roller 27 Spring clutch 28 Rotation input section 29 Rotation output section 30 Sleeve 31 Operating member 33 Swing lever

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location G03G 15/16 7818-2H 21/00 119 6605-2H // G03G 15/20 101 6830-2H

Claims (4)

[Claims] 1. An endless belt is stretched between at least two rollers, and one roller is driven to rotate so that the belt travels between the rollers to swing the one roller. A device for controlling the meandering of a belt by oscillating the roller alternately in either direction, utilizing the rotational force of a drive source that rotationally drives the drive roller for running the belt, A belt meandering control device characterized in that a roller provided so as to be tiltable with respect to the rotation axis of the drive roller is rocked. 2. A swing roller in which an endless belt is stretched between at least two rollers, one roller is a drive roller, and one roller is driven to be rotatable and swingable. In a device for controlling the meandering of the belt by swinging the swing roller as needed, a transmission means for controlling transmission of a rotational force of a drive source for rotationally driving the drive roller, and the transmission means. Swing control means for inclining the swing roller in either direction by the rotational force transmitted by means of the rotation force, and actuating means for responding to the deviation of the belt to cause transmission or non-transmission of the transmission means. And a belt meandering control device. 3. The belt meandering control device according to claim 2, wherein the transmission means is a spring clutch. 4. The belt meandering control device according to claim 1, wherein the belt is a heat resistant belt for heat fixing.