JP5183452B2 - Belt drive device and image forming apparatus - Google Patents

Description

  The present invention relates to a belt driving device that drives a belt such as an intermediate transfer belt, a fixing belt, and a recording paper conveyance belt, and an image forming apparatus having the belt driving device.

  Conventional image forming apparatuses are provided with various types of belts such as an intermediate transfer belt, a fixing belt, and a recording paper conveyance belt.

  These belts are driven to rotate by being suspended by a plurality of rollers. During the belt rotation process, the belt moves toward one end or the other end in the width direction (hereinafter referred to as meandering). Tend to. Due to the meandering of the belt, the belt may fall off from the roller that is suspending the belt, or the end of the belt may be damaged.

  Therefore, there is an edge sensor that detects an edge position in the width direction of the belt, and based on the detection result of the edge sensor, there is an apparatus that corrects the meandering of the belt by controlling the tilting operation of the steering roller that supports the belt. (For example, refer to Patent Document 1).

This edge sensor has a contactor that contacts one end of the belt and a displacement sensor that detects a positional variation of the contactor, and continuously detects meandering of the belt.
JP 2000-034031 A

  In an image forming apparatus having such an edge sensor, when an operator replaces the belt, the belt is mounted in a state where the contact does not come into contact with the end of the belt, for example, a state where the belt rides on the contact. There was a case.

  FIG. 8 is a diagram for explaining a state in which the belt rides on the contact of the edge sensor.

  As shown by the dotted line in FIG. 8A, the intermediate transfer belt 8 is supported by a steering roller 10, a belt driving roller 11, and a rotating roller 21, and is applied with an appropriate tension. As shown in FIG. 4A, a contact 202 for detecting the amount of movement of the intermediate transfer belt 8 in the width direction is pressed against the end of the intermediate transfer belt 8 with an appropriate force. .

  Here, when the operator replaces the intermediate transfer belt 8, the intermediate transfer belt 8 is loosened as shown by the solid line by moving the steering roller 10 in the direction of the arrow in FIG. It becomes easy to exchange. At this time, since the looseness of the intermediate transfer belt 8 is large, the end of the intermediate transfer belt 8 is detached from the contactor 202.

  After the replacement of the intermediate transfer belt 8, when the steering roller 10 is returned again to apply tension to the intermediate transfer belt 8, the operator retracts the contact 202 to the end side of the intermediate transfer belt 8. If this evacuation is not performed well, as shown in FIGS. 4B and 8B, the contact 202 does not contact the end of the intermediate transfer belt 8, and the intermediate transfer belt 8 does not contact the contact 202. It will be in the state of riding on the tip of.

  In this case, since the normal belt meandering control is not performed, the positional accuracy of the image transferred onto the recording paper is lowered, or the contact 202 and the intermediate transfer belt 8 are rubbed due to long-term use. There was a problem that was damaged.

  Therefore, the present invention improves the positional accuracy of the image transferred to the recording paper by preventing the meandering control from being normally performed because the contact is not in contact with the end of the belt, The purpose is to prevent damage to the belt.

  In order to achieve the above object, a belt drive device according to the present invention abuts on a belt that rotates and moves in a predetermined direction, and an end of the belt in the width direction orthogonal to the predetermined direction, and the belt in the width direction of the belt. A contact that is displaced according to the position; a sensor that detects the position of the contact; and a control unit that controls the position of the belt in the width direction based on a detection result of the sensor. The means is characterized in that the belt is moved in the width direction and in a direction away from the contact according to the exchange of the belt.

  The image forming apparatus according to the present invention includes the belt driving device and an image carrier that carries a toner image on a surface thereof, and the toner image is primarily transferred from the image carrier on the belt. An intermediate transfer belt, a fixing belt that heats and fixes a toner image formed on the recording paper, or a recording paper conveyance belt that conveys the recording paper.

  According to the present invention, it is possible to prevent the meandering control from being performed normally, improve the positional accuracy of the image transferred to the recording paper, and prevent the belt from being damaged.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a cross-sectional view illustrating an overall configuration of an image forming apparatus including a belt driving device.

  The image forming apparatus 1 is an electrophotographic full-color printer that forms an image on recording paper. The image forming apparatus 1 includes four photosensitive drums 2a to 2d, chargers 3a to 3d, cleaners 4a to 4d, laser scanning units 5a to 5d, transfer blades 6a to 6d, developing units 7a to 7d, and an intermediate transfer belt 8. And a cleaner 12 are provided. Further, the image forming apparatus 1 is provided with a steering roller 10 that supports the intermediate transfer belt 8 and a belt driving roller 11 that rotates and moves the intermediate transfer belt 8 in a predetermined direction.

  A plurality of recording sheets S set on the manual feed tray 13 are separated into a single sheet by a pickup roller 14 and a separation roller 15 and fed. On the other hand, a plurality of recording sheets S stored in the sheet feeding cassette 17 are separated and fed by a pickup roller 18 and a separation roller 19 and then conveyed by a vertical path roller 20.

  The fed recording sheet S is conveyed to the secondary transfer roller 22 while the registration roller 16 sets the registration timing. Here, the rollers 14, 15, 16, 18, 19, and 20 for transporting the recording paper S are each driven by an independent stepping motor in order to realize a high-speed and stable transport operation.

  On the other hand, the chargers 3a to 3d uniformly charge the surfaces of the photosensitive drums 2a to 2d as image carriers that carry toner images. Each of the laser scanning units 5a to 5d using the semiconductor laser as a light source irradiates the photosensitive drums 2a to 2d of the respective colors with lasers, thereby forming electrostatic latent images on the surfaces of the respective photosensitive drums 2a to 2d. . The developing units 7a to 7d develop the electrostatic latent image as a toner image.

  Next, the transfer blades 6 a to 6 d transfer the color toner images developed on the photosensitive drums 2 a to 2 d to the intermediate transfer belt 8. The toner image on the intermediate transfer belt 8 is transferred to the recording paper at the nip portion between the rotating roller 21 and the secondary transfer roller 22. Then, heat is applied to the toner image transferred onto the recording paper by the fixing device 23 having a heating roller, and the toner image is fixed onto the recording paper.

  In double-sided printing, the recording paper S that has passed through the fixing unit 23 is guided in the direction of the double-sided reversing path 27 and then conveyed in the reverse direction so that the front and back are reversed and conveyed to the double-sided path 28. The recording paper S that has passed through the double-sided path 28 is conveyed again by the vertical path roller 20, forms an image on the second side as with the first side, and is discharged to the paper discharge tray 25 by the paper discharge roller 24.

  FIG. 2 is a diagram showing a schematic configuration for explaining the meandering correction control of the intermediate transfer belt 8.

  The belt driving motor 210 rotationally drives the belt driving roller 11 in order to convey the intermediate transfer belt 8 in the arrow direction shown in FIG. The steering roller 10 is a roller for correcting movement variation (meandering) in the width direction of the intermediate transfer belt 8. A belt HP sensor 205 and an edge sensor 203 are disposed downstream of the steering roller 10 in the belt conveyance direction.

  The belt HP sensor 205 detects a home position mark 204 attached to the back surface of the intermediate transfer belt 8 and generates a belt position reference signal (HP signal). The edge sensor 203 detects the amount of movement (displacement) of the contact 202 arranged so as to contact the end (edge) of the intermediate transfer belt 8 and outputs an output signal corresponding to the meandering of the intermediate transfer belt 8. Occur.

  A position variation in the width direction of the intermediate transfer belt 8 can be detected according to the detection result of the edge sensor 203, and the tilting operation of the steering roller 10 is controlled based on the position variation. Thereby, the meandering of the intermediate transfer belt 8 can be corrected.

  As the belt drive motor 210 and the steering motor 209, a stepping motor capable of controlling the rotation angle and rotation speed with high accuracy is used.

  FIG. 3 is a diagram for explaining the principle of meandering correction of the intermediate transfer belt.

  From the left of this figure, a front view of the eccentric cam 208, a side view of the eccentric cam 208 and the steering roller 10, and a front view of the steering roller 10 are shown.

  As shown in FIG. 3A, in the state where the eccentric cam 208 stops at a predetermined angle and the steering roller 10 is held substantially horizontal (tilt is almost zero) corresponding to the stop angle, the basic operation is basically performed. The intermediate transfer belt 8 does not move (meander) in the width direction.

  3B, when the eccentric cam 208 is rotated by driving the steering motor 209, the swing arm 206 swings in the θ1 direction according to the amount of eccentricity of the eccentric cam 208. Thereby, since one end of the steering roller 10 is lifted by the swing arm 206, the steering roller 10 is inclined according to the lift amount. At this time, the intermediate transfer belt 8 wound around the steering roller 10 moves to the roller end side lifted by the swing arm 206.

  On the other hand, as shown in FIG. 3C, when the eccentric cam 208 is rotated by driving the steering motor 209, the swing arm 206 swings in the θ2 direction according to the amount of eccentricity of the eccentric cam 208. . Thereby, since one end of the steering roller 10 is pushed down by the swing arm 206, the steering roller 10 is inclined according to the amount of the push-down. At this time, the intermediate transfer belt 8 wound around the steering roller 10 moves to the side opposite to the roller end pushed down by the swing arm 206.

  Therefore, the position variation in the width direction of the intermediate transfer belt 8 is continuously detected by the edge sensor 203, and the tilting operation of the steering roller 10 is controlled based on the detection result, whereby the meandering of the intermediate transfer belt 8 is performed. Can be corrected.

  FIG. 4 is a diagram illustrating a specific configuration of the edge sensor.

  Here, FIG. 4A shows a state in which the contact 202 is normally pressed against the end of the intermediate transfer belt 8. FIG. 4B shows a state in which the intermediate transfer belt 8 rides on the contact 202 without the contact 202 being pressed against the end of the intermediate transfer belt 8.

  As shown in FIG. 4A, one end of the contactor 202 is held in pressure contact with the end of the intermediate transfer belt 8 by receiving a pulling force from the spring 401. The pressing force of the contactor 202 by the spring 401 is set to an appropriate magnitude so as not to deform the intermediate transfer belt 8.

  Further, the intermediate portion of the contactor 202 is rotatably supported by the support shaft 402. The displacement sensor 403 is disposed to face the other end side of the contactor 202. The displacement sensor 403 is an optical sensor that irradiates the contactor 202 light, receives light reflected from the contactor 202, and detects the displacement of the contactor 202 according to the amount of received light.

  The edge sensor 203 replaces the movement amount in the width direction orthogonal to the traveling direction of the intermediate transfer belt 8 with the movement of the contactor 202 that presses against the end of the intermediate transfer belt 8. At this time, since the output level of the displacement sensor 403 varies according to the displacement of the contactor 202, the position variation of the end portion of the intermediate transfer belt 8 can be continuously detected based on the sensor output.

  On the other hand, as shown in FIG. 4B, when the contact 202 does not contact the end of the intermediate transfer belt 8 and the intermediate transfer belt 8 rides on the contact 202, the edge sensor 203 operates as the intermediate transfer belt. 8 position variation cannot be detected accurately.

  As in the example of this figure, the contactor 202 remains at an appropriate position where the output of the displacement sensor 403 indicates a normal value. This is because the intermediate transfer belt 8 is supported by the steering roller 10, the belt driving roller 11, and the rotating roller 21 with an appropriate tension, so that the force causes the force from the tip of the contactor 202 toward the support shaft 402. Because it is added.

  In this riding state, an abnormality cannot be detected based on the output of the edge sensor 203, and the intermediate transfer belt 8 continues to be driven as usual.

  FIG. 5 is a control block diagram of the image forming apparatus.

  The control unit 501 includes a CPU 502, a ROM 503, and a RAM 504. The CPU 502 is a control circuit that controls the entire image forming apparatus 1. The ROM 503 stores a control program for controlling various processes executed by the image forming apparatus 1.

  A RAM 504 is a system work memory for the CPU 502 to operate, and also functions as an image memory for temporarily storing image data. A hard disk drive (HDD) 505 stores data such as system software and image data.

  In the control unit 501, the CPU 502 is configured to acquire a detection signal from the belt HP sensor 205 for detecting the home position mark 204. Further, the CPU 502 acquires a detection signal from the edge sensor 203 during the rotational movement of the intermediate transfer belt 8 and calculates a position change amount (hereinafter referred to as displacement) corresponding to the meandering amount of the intermediate transfer belt 8.

  Then, the CPU 502 outputs a steering control signal including a driving direction and a driving amount to the steering motor 209 so as to reduce the meandering according to the calculated displacement of the intermediate transfer belt 8, and drives the steering motor 209.

  The control unit 501 is connected to a display unit 506 configured by a touch panel display or the like for displaying the state of the image forming apparatus 1 and receiving an operation input from the user.

  FIG. 6 is a diagram for explaining the principle of returning from the belt riding state by performing steering control.

  FIG. 6A shows a state where the intermediate transfer belt 8 rides on the contact 202. In this case, the steering roller 10 is tilted by a preset inclination α in order to return the intermediate transfer belt 8 from the state where the intermediate transfer belt 8 rides on the contactor 202 to the normal state.

  When the steering control is performed in this way, as shown in FIG. 6B, the intermediate transfer belt 8 moves away from the contact 202 in accordance with the inclination of the steering roller 10, and the intermediate transfer belt 8 is moved to the contact. A state (normal state) where the vehicle is not on board 202 is entered.

  FIG. 7 is a flowchart showing steering control for canceling belt riding.

  A program for executing this flowchart is stored in the ROM 503 and is executed by being read by the CPU 502.

  First, the CPU 502 determines whether or not the intermediate transfer belt 8 has been replaced (S701). This determination is made based on whether or not an input indicating that the intermediate transfer belt 8 has been replaced has been made by the user from the display unit 506.

  If the intermediate transfer belt 8 has not been replaced, it is considered that there is no possibility that the intermediate transfer belt 8 is riding on the contactor 202, and thus this control flow ends.

  When the intermediate transfer belt 8 is replaced, the CPU 502 drives the belt drive motor 210 to rotate the intermediate transfer belt 8 (S702). Next, the CPU 502 drives the steering motor 209 to incline the steering roller 10 in the first direction by a preset inclination α (S703).

  Thus, by tilting the steering roller 10 in the first direction, the intermediate transfer belt 8 starts to move away from the contactor 202. Here, even if the intermediate transfer belt 8 rides on the contactor 202, the intermediate transfer belt 8 moves until the ride-on state is finally canceled by the movement of the intermediate transfer belt 8.

  Thereafter, the CPU 502 determines whether or not the output of the edge sensor 203 is within a predetermined range (S704). That is, when the running of the intermediate transfer belt 8 is canceled, the position of the contact 202 is the position shown in FIG. 6B, and the edge sensor 203 is within a predetermined margin from this position. Determine whether there is any output.

  When the output of the edge sensor 203 is within the predetermined range, the CPU 502 drives the steering motor 209 to tilt the steering roller 10 in the second direction opposite to the first direction (S705). ). As a result, the intermediate transfer belt 8 starts to move in a direction approaching the contact 202, and finally the intermediate transfer belt 8 comes into contact with the contact 202.

  Next, the CPU 502 determines whether or not the output of the edge sensor 203 is fluctuating (S706). When the intermediate transfer belt 8 is eliminated, the steering roller 10 is tilted so that the intermediate transfer belt 8 comes into contact with the contact 202 and the output of the edge sensor 203 changes. On the other hand, if the intermediate transfer belt 8 has not been lifted, the output of the edge sensor 203 does not fluctuate even if the steering roller 10 is tilted.

  When the output of the edge sensor 203 is fluctuating, the intermediate transfer belt 8 is not on the contactor 202, so the CPU 502 controls the meandering correction of the intermediate transfer belt 8 by controlling the driving of the steering motor 209. (S707). Thereafter, this control flow is terminated.

  On the other hand, if it is determined in step S704 that the output of the edge sensor 203 is not within the predetermined range, or if it is determined in step S706 that the output of the edge sensor 203 has not changed, an error is displayed on the display unit 506. (S708). Thereby, it can be notified to the user that the intermediate transfer belt 8 has run over the contactor 202.

  As described above, according to the present embodiment, it is possible to eliminate the intermediate transfer belt 8 and prevent the meandering correction control from being performed normally. As a result, it is possible to improve the positional accuracy of the image transferred to the recording paper and prevent the intermediate transfer belt from being damaged.

  In the above description, the intermediate transfer belt is described as an example of the belt, but is not limited thereto. For example, the present invention may be applied to meandering correction control for a fixing belt, a recording paper conveyance belt, and the like and control for eliminating the belt running.

  In the above description, the method for notifying the belt riding state has been described by taking a message on the display unit as an example, but is not limited thereto. For example, the user may be notified by voice.

1 is a cross-sectional view illustrating an overall configuration of an image forming apparatus including a belt driving device. It is a figure which shows schematic structure for demonstrating the meandering correction | amendment control of an intermediate transfer belt. FIG. 6 is a diagram for explaining the principle of meandering correction of an intermediate transfer belt. It is a figure which shows the specific structure of an edge sensor. 2 is a control block diagram of the image forming apparatus. FIG. It is a figure explaining the principle which returns from a belt riding state by performing steering control. It is a flowchart which shows the steering control for canceling | releasing belt riding. It is a figure for demonstrating the riding state of the belt to the contactor of an edge sensor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 8 Intermediate transfer belt 10 Steering roller 11 Belt drive roller 202 Contact 203 Edge sensor 205 Belt HP sensor 209 Steering motor 210 Belt drive motor 403 Displacement sensor 501 Control unit 502 CPU
503 ROM
504 RAM
505 HDD
506 Display

Claims (6)

A belt that rotates in a predetermined direction;
A contact that abuts against an end of the belt in the width direction perpendicular to the predetermined direction and is displaced according to the position of the belt in the width direction;
A sensor for detecting the position of the contact;
Control means for controlling the position of the belt in the width direction based on the detection result of the sensor,
The control means moves the belt in the width direction and in a direction away from the contact in response to the replacement of the belt. The belt is supported by a plurality of rollers,
2. The belt driving device according to claim 1, wherein the control unit controls the position of the belt in the width direction by inclining an axis of any one of the plurality of rollers.   The control means tilts the shaft of one of the plurality of rollers in a first direction in response to the replacement of the belt, thereby moving the belt from the contact in the width direction. The belt is moved in the width direction and in the direction approaching the contact by tilting the roller shaft in a second direction opposite to the first direction. The belt driving device according to claim 2.   The control means determines whether the output of the sensor has changed after tilting the roller shaft from the first direction to the second direction, and the output of the sensor has not changed. The belt driving device according to claim 3, wherein the belt driving device is determined to be abnormal.   5. The belt driving device according to claim 4, further comprising notification means for notifying the user of an abnormality when the control means determines that an abnormality has occurred. A belt driving device according to any one of claims 1 to 5;
An image carrier that carries a toner image on the surface,
The belt is an intermediate transfer belt on which the toner image is primarily transferred from the image carrier, a fixing belt that heats and fixes the toner image formed on the recording paper, or a recording paper conveyance belt that conveys the recording paper An image forming apparatus.

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