JP2021014037A - Optical scanner and image formation apparatus provided with the same - Google Patents

Abstract

To provide an optical scanner which can suppress elongation and breakage of a linear member by continuously applying a load to the liner member at the time of stopping of a cleaning holder, and an image formation apparatus provided with the same.SOLUTION: An optical scanner includes a housing, a permeable member, a linear member, a driving part, a cleaning holder, pa cleaning member, a stopper, and a control part. The control part controls driving of the driving part. The control part can execute a cleaning mode including at least one of a forward operation of moving the cleaning holder in an extension direction of the permeable member by traveling the linear member in a first direction, and a backward operation of moving the cleaning holder in an opposite direction to the forward operation by traveling the linear member in a second direction after execution of the forward operation. The control part executes a load release operation of moving the cleaning holder by a predetermined amount in an opposite direction to the forward operation or the backward operation that is the final operation of the cleaning mode after execution of the cleaning mode.SELECTED DRAWING: Figure 6

Description

The present invention relates to an optical scanning device that irradiates an image carrier with light to form an electrostatic latent image in an electrophotographic image forming apparatus, and an image forming apparatus including the optical scanning device.

An optical scanning device is provided in an image forming device such as a copier or a printer that adopts an electrophotographic method. The optical scanning device irradiates the charged image carrier with light to form an electrostatic latent image on the image carrier. The housing of the optical scanning device includes a housing portion having one surface open and a cover portion covering the opening. A scanning optical system is incorporated inside the accommodating portion, and an outlet for light emitted from the scanning optical system is formed in the cover portion corresponding to the image carrier. Further, the outlet is covered with a transparent member. The transmissive member is a member that is transparent to the light emitted from the scanning optical system.

The transmissive member is provided to prevent toner, dust, etc. from entering the inside of the optical scanning device. If toner, dust, or the like adheres to a part or all of a plurality of optical components arranged inside the optical scanning device, the optical characteristics may deteriorate. Deterioration of optical characteristics deteriorates the quality of images formed on recording media such as paper.

On the other hand, when toner, dust, or the like adheres to a part or all of the outer surface of the transparent member, the optical characteristics may deteriorate. Therefore, it is necessary to periodically clean the outer surface of the transparent member. For example, Patent Document 1 discloses an automatic cleaning mechanism that automatically cleans the outer surface of the transparent member. In this automatic cleaning mechanism, a plurality of cleaning holders are simultaneously moved in the same direction by each screw shaft arranged along the longitudinal direction of the plurality of transparent members. Each cleaning holder holds one cleaning member, and each cleaning holder slides on the outer surface of the corresponding permeable member as each cleaning holder moves its own movement path. As a result, each transparent member is cleaned at the same time.

Further, in Patent Document 2, two cleaning holders holding two cleaning members each are connected to the linear member, and the two cleaning holders move along the transparent member as the linear member travels in a ring shape. At the same time, an optical scanning device in which each cleaning member slides on a corresponding transmissive member is disclosed. Then, it is described that the running of the linear member is stopped when the cleaning holder comes into contact with the stopper at one end of the moving path.

JP-A-2009-143108 Japanese Unexamined Patent Publication No. 2016-31467

In the configuration of Patent Document 2, after the cleaning holder is reciprocated, it is stopped in a state of being in contact with the stopper. When the cleaning holder is in contact with the stopper, tension (load) continues to be applied to the linear member until the next cleaning operation is executed. As a result, the linear member is stretched, and in the worst case, the linear member may be broken.

In view of the above problems, the present invention provides an optical scanning device capable of suppressing elongation or breakage of the linear member due to continuous load applied to the linear member when the cleaning holder is stopped, and an image forming apparatus provided with the optical scanning device. The purpose is to provide.

In order to achieve the above object, the first configuration of the present invention is an optical scanning device that irradiates an image carrier with laser light to form an electrostatic latent image, and comprises a housing, a transmissive member, and a wire. It includes a shape member, a drive unit, a cleaning holder, a cleaning member, a stopper, and a control unit. The housing is formed with a laser beam outlet extending in the main scanning direction of the laser beam corresponding to the image carrier. The transmissive member has transparency to the laser light, extends in the main scanning direction of the laser light, and seals the emission port of the laser light. The linear member is stretched in an annular shape on the housing. The drive unit causes the linear member to travel in the first direction and the second direction. The cleaning holder is fixed to the linear member and moves in the extending direction of the transparent member when the linear member is annularly traveled by the drive unit. The cleaning member is fixed to the cleaning holder and slides with respect to the transparent member as the cleaning holder moves to clean the transparent member. The stopper is placed at the end of the movement path of the cleaning holder to regulate the movement of the cleaning holder. The control unit controls the drive of the drive unit. The control unit moves the linear member in the first direction, so that the cleaning holder moves along the extending direction of the transparent member, and after the outbound operation is executed, the linear member is moved in the second direction. By traveling, it is possible to execute a cleaning mode including at least one of a return operation in which the cleaning holder moves in the opposite direction to the outward operation. After executing the cleaning mode, the control unit executes a load release operation of moving the cleaning holder by a predetermined amount in the direction opposite to the outbound operation or the inbound operation, which is the final operation of the cleaning mode.

According to the first configuration of the present invention, after the cleaning mode is executed, the cleaning holder can be stopped in a state of being separated from the stopper by performing a load release operation of moving the cleaning holder in the opposite direction by a predetermined amount. it can. Therefore, it is possible to avoid a state in which tension (load) is continuously applied to the linear member, and it is possible to suppress elongation and breakage of the linear member.

Cross-sectional view schematically showing the overall configuration of the image forming apparatus 1 on which the optical scanning apparatus 12 of the present invention is mounted. Top view showing the cover part 12c of the optical scanning apparatus 12 which concerns on one Embodiment of this invention. Top view for explaining the operation of the cleaning holder 51 provided in the cover part 12c in the optical scanning apparatus 12 of this embodiment. Cross-sectional view of a part of the cover portion 12c in the optical scanning device 12 of the present embodiment as viewed from the moving direction of the cleaning holder 51. A block diagram showing an example of a control path used in the image forming apparatus 1. A flowchart showing a first control example of drive control of the take-up motor 55 in the cleaning mode. Flow chart showing a second control example of drive control of the take-up motor 55 in the cleaning mode Cross-sectional view of a part of the cover portion 12c in the optical scanning device 12 of the present embodiment as viewed from a direction orthogonal to the moving direction of the cleaning holder 51. Top view showing the moving mechanism of the cleaning holder 51 in the optical scanning apparatus 12 used for the monochrome image forming apparatus.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view schematically showing an overall configuration of an image forming apparatus 1 on which the optical scanning apparatus of the present invention is mounted. The image forming apparatus 1 is a tandem type color printer. The image forming apparatus 1 includes photoconductor drums 11a to 11d that are rotatable as an image carrier. For the photoconductor drums 11a to 11d, an organic photoconductor (OPC photoconductor) on which an organic photosensitive layer is formed, an amorphous silicon photoconductor on which an amorphous silicon photosensitizer layer is formed, or the like is used. The photoconductor drums 11a to 11d are arranged in tandem corresponding to each color of magenta, cyan, yellow, and black.

A developing device 2a, a charging device 13a, and a cleaning device 14a are arranged around the photoconductor drum 11a. Similarly, developing devices 2b to 2d, chargers 13b to 13d, and cleaning devices 14b to 14d are arranged around the photoconductor drums 11b to 11d, respectively. Further, the optical scanning device 12 is arranged below the developing devices 2a to 2d. In addition, in this specification, the bottom and the top indicate the bottom and the top in the drawing.

The developing devices 2a to 2d are arranged on the right side of the photoconductor drums 11a to 11d, respectively. The developing devices 2a to 2d face the photoconductor drums 11a to 11d, respectively, and supply toner to the photoconductor drums 11a to 11d. In addition, in this specification, right and left indicate right and left in a drawing.

The chargers 13a to 13d are arranged on the upstream side of the developing devices 2a to 2d with respect to the rotation direction of the photoconductor drums 11a to 11d, and face the surfaces of the photoconductor drums 11a to 11d, respectively. The chargers 13a to 13d uniformly charge the surfaces of the photoconductor drums 11a to 11d, respectively.

The optical scanning device 12 emits light on the surfaces of the photoconductor drums 11a to 11d uniformly charged by the chargers 13b to 13d based on image data such as characters and patterns input to the image input unit from a personal computer or the like. Is irradiated (light scanning) to form an electrostatic latent image on the surfaces of the photoconductor drums 11a to 11d.

The housing 12a of the optical scanning device 12 includes an accommodating portion 12b having one surface open and a cover portion 12c covering the opening. The scanning optical system 120 is incorporated in the accommodating portion 12b. The cover portion 12c is formed with an outlet for light (laser light) emitted from the scanning optical system 120 corresponding to the photoconductor drums 11a to 11d. Further, as will be described later, each outlet is covered with a transparent member 52 (see FIG. 2). The transmissive member 52 has transparency to the light emitted from the scanning optical system 120.

The scanning optical system 120 includes a laser light source (not shown) and a polygon mirror. Further, the scanning optical system 120 includes at least one reflecting mirror and a lens corresponding to the photoconductor drums 11a to 11d. The laser light emitted from the laser light source passes through the polygon mirror, the reflection mirror group, and the lens group from the downstream side in the rotation direction of the photoconductor drums 11a to 11d with respect to the chargers 13a to 13d, and the photoconductor drums 11a to 11a to Each surface of 11d is irradiated. As a result, an electrostatic latent image is formed on the surfaces of the photoconductor drums 11a to 11d. These electrostatic latent images are developed into toner images by the developing devices 2a to 2d.

The endless intermediate transfer belt 17 is stretched on a tension roller 6, a driving roller 25, and a driven roller 27. When the drive roller 25 is rotated by a motor (not shown), the intermediate transfer belt 17 is circulated and driven in the clockwise direction of FIG.

The photoconductor drums 11a to 11d are arranged adjacent to each other along the transport direction (arrow direction in FIG. 1) below the intermediate transfer belt 17. Further, the photoconductor drums 11a to 11d are in contact with the intermediate transfer belt 17, respectively. The primary transfer rollers 26a to 26d face the photoconductor drums 11a to 11d with the intermediate transfer belt 17 interposed therebetween. The primary transfer rollers 26a to 26d are pressure-contacted with the intermediate transfer belt 17, respectively, to form a primary transfer portion together with the photoconductor drums 11a to 11d. In these primary transfer portions, the toner image is transferred to the intermediate transfer belt 17. Specifically, by applying the primary transfer voltage to the primary transfer rollers 26a to 26d, the toner images of the photoconductor drums 11a to 11d are sequentially transferred to the intermediate transfer belt 17 at a predetermined timing. As a result, a full-color toner image is formed in which four color toner images of magenta, cyan, yellow, and black are superimposed on the surface of the intermediate transfer belt 17 with a predetermined positional relationship.

The secondary transfer roller 34 faces the drive roller 25 with the intermediate transfer belt 17 interposed therebetween. The secondary transfer roller 34 is pressed against the intermediate transfer belt 17 to form a secondary transfer portion together with the drive roller 25. In this secondary transfer unit, the toner image on the surface of the intermediate transfer belt 17 is transferred to the paper P by applying the secondary transfer voltage to the secondary transfer roller 34. After transferring the toner image, the belt cleaning device 31 cleans the toner remaining on the intermediate transfer belt 17.

A paper feed cassette 32 is arranged below the image forming apparatus 1. The paper feed cassette 32 can store a plurality of sheets P. A stack tray 35 for manual paper feeding is arranged on the right side of the paper feed cassette 32. A first paper transport path 33 is arranged on the left side of the paper feed cassette 32. The first paper transport path 33 transports the paper P fed from the paper feed cassette 32 to the secondary transfer unit. A second paper transport path 36 is arranged on the left side of the stack tray 35. The second paper transport path 36 transports the paper fed from the stack tray 35 to the secondary transfer unit. Further, a fixing portion 18 and a third paper transport path 39 are arranged on the upper left side of the image forming apparatus 1. The fixing unit 18 performs a fixing process on the paper P on which the image is formed. The third paper transport path 39 transports the fixed paper P to the paper discharge unit 37.

The paper P stored in the paper feed cassette 32 is fed one by one to the first paper transport path 33 side by the pickup roller 33b and the handling roller pair 33a.

The first paper transport path 33 and the second paper transport path 36 meet in front of (upstream side) the resist roller pair 33c. The resist roller pair 33c conveys the paper P to the secondary transfer unit at the timing of the image forming operation on the intermediate transfer belt 17 and the paper feeding operation to the secondary transfer unit. The full-color toner image on the intermediate transfer belt 17 is secondarily transferred by the secondary transfer roller 34 to which the secondary transfer voltage is applied to the paper P conveyed to the secondary transfer unit. The paper P on which the full-color toner image is transferred is conveyed to the fixing unit 18.

The fixing portion 18 includes a fixing belt heated by a heater, a fixing roller inscribed in the fixing belt, a pressure roller which is pressed against the fixing roller with the fixing belt sandwiched, and the like. The fixing unit 18 heats and pressurizes the paper P on which the toner image is transferred. As a result, the fixing process is carried out. The front and back sides of the paper P on which the toner image is fixed in the fixing portion 18 are reversed in the fourth paper transport path 40 as needed. After that, the paper P is again conveyed to the secondary transfer section via the resist roller pair 33c, and then a new toner image is secondarily transferred to the back surface of the paper P by the secondary transfer roller 34 and fixed at the fixing section 18. Toner. The paper P on which the toner image is fixed is discharged to the paper discharge unit 37 by the discharge roller pair 19 through the third paper transport path 39.

Next, the optical scanning apparatus 12 will be described with reference to FIGS. 2, 3, and 4. FIG. 2 is a plan view showing the cover portion 12c of the optical scanning device 12. FIG. 3 is a plan view for explaining the operation of the cleaning holder 51 provided on the cover portion 12c. FIG. 4 is a cross-sectional view of a part of the cover portion 12c viewed from the moving direction of the cleaning holder 51, and the cleaning holder 51 is viewed from the front.

As described above, the housing 12a of the optical scanning apparatus 12 includes the accommodating portion 12b and the cover portion 12c attached to the accommodating portion 12b, and the cover portion 12c includes four photoconductor drums 11a to 11d. Correspondingly, four laser light outlets are arranged side by side. The shape of each outlet is a rectangular shape that is long in the main scanning direction of the corresponding laser beam, and each outlet is formed so that their longitudinal directions are parallel to each other. Each outlet is sealed by a rectangular plate-shaped transparent member 52. The four transparent members 52 are arranged side by side so that their longitudinal directions are parallel to each other. Each transmissive member 52 is provided to prevent toner, dust, and the like from entering the inside of the optical scanning device 12. Each transparent member 52 is, for example, a glass cover.

The optical scanning device 12 includes two cleaning holders 51, a first cleaning holder 511 and a second cleaning holder 512.

Each cleaning holder 51 has a holding portion 51a (see FIG. 4). The holding portion 51a extends so as to straddle between two adjacent transparent members 52, and holds the two cleaning members 53. Each cleaning holder 51 is provided on the outer surface (the surface on the photoconductor drums 11a to 11d side) of the cover portion 12c. Each cleaning member 53 is held by each holding portion 51a so as to be arranged corresponding to each transparent member 52. Each cleaning member 53 is, for example, a rubber pad. As the material of the rubber pad, for example, silicon rubber can be used. Each cleaning holder 51 is made of, for example, resin. The cleaning member 53 is not limited to the rubber pad, and may be, for example, a non-woven fabric.

Each cleaning holder 51 is connected to a linear member 54 stretched in an annular shape so as to pass between two adjacent transparent members 52. The linear member 54 travels in an annular shape by the driving force of the take-up motor 55, which is a driving unit. The linear member 54 is, for example, a wire.

The four cleaning members 53 slide on the outer surfaces (surfaces on the photoconductor drums 11a to 11d side) of the four transparent members 52 as the linear member 54 travels in an annular manner. As a result, the outer surface of each transparent member 52 is simultaneously cleaned by the corresponding cleaning member 53.

The take-up motor 55 can rotate forward and reverse. This makes it possible to repeatedly perform the cleaning process of each transparent member 52. In the present embodiment, in one cleaning process, the take-up motor 55 is rotated in the forward and reverse directions to reciprocate the corresponding cleaning member 53 along the longitudinal direction of each transparent member 52. The cleaning process is executed by the user inputting a process start command from the operation unit 80 (see FIG. 5) or a higher-level device such as a personal computer when the state of the image forming apparatus 1 is in the maintenance mode. To. Further, for example, every time about 10,000 sheets are printed (image formation), the cleaning process may be executed periodically.

In the present embodiment, the first cleaning holder 511 and the second cleaning holder 512 are opposite to each other along the longitudinal direction (main scanning direction of the laser beam) of each transmissive member 52 as the linear member 54 travels in an annular shape. Move linearly in the direction. A first stopper 56a is provided at one end of the moving path of the first cleaning holder 511, and a second stopper 56b is provided at one end of the moving path of the second cleaning holder 512. The first and second stoppers 56a and 56b are provided on one side in the longitudinal direction of each of the two transparent members 52 adjacent to each other. When the first cleaning holder 511 or the second cleaning holder 512 moves to one end of the movement path and comes into contact with the corresponding first stopper 56a or second stopper 56b, the linear member 54 stops traveling. When the running of the linear member 54 is stopped and the load acting on the take-up motor 55 is increased, the rotation direction of the take-up motor 55 is reversed or the operation of the take-up motor 55 is stopped. For example, resin can be used as the material of the first stopper 56a and the second stopper 56b. When the first stopper 56a and the second stopper 56b are formed of resin, the first stopper 56a and the second stopper 56b may be integrally formed with the cover portion 12c.

Here, the operation of the cleaning holder 51 during one cleaning process will be described with reference to FIGS. 2 and 3. In the present embodiment, as described above, in one cleaning process, the corresponding cleaning member 53 reciprocates once along the longitudinal direction of each transparent member 52. Here, a case where the traveling direction of the linear member 54 changes from the direction indicated by the arrow D1 (first direction) to the direction indicated by the arrow D2 (second direction) during the cleaning process will be described.

When the cleaning process is started, the linear member 54 travels in the first direction indicated by the arrow D1 (see FIG. 2). As a result, the first cleaning holder 511 and the second cleaning holder 512 move from the position shown in FIG. 2 to the position shown in FIG. 3, and the first cleaning holder 511 moves to the first stopper 56a at one end of the moving path. Contact. As a result, the running of the linear member 54 is stopped, and the first cleaning holder 511 and the second cleaning holder 512 are stopped. At this time, the load acting on the take-up motor 55 increases.

In response to this increase in load, the rotation direction of the take-up motor 55 is reversed, and the linear member 54 travels in the second direction (opposite to the first direction) indicated by the arrow D2 (see FIG. 3). Then, the first cleaning holder 511 and the second cleaning holder 512 move from the position shown in FIG. 3 to the position shown in FIG. 2, and the second cleaning holder 512 hits the second stopper 56b at one end of the moving path. Get in touch. As a result, the running of the linear member 54 is stopped, and the operations of the first cleaning holder 511 and the second cleaning holder 512 are stopped. At this time, the load acting on the take-up motor 55 increases. The take-up motor 55 stops in response to this increase in load.

Further, during the cleaning process, the two cleaning members 53 held in each cleaning holder 51 move in the same direction. Here, if one cleaning holder 51 holds one cleaning member 53, as many cleaning holders 51 as the number of transparent members 52 are required, so one cleaning holder 51 as in the present embodiment. The length of the linear member 54 for moving the cleaning holder 51 is longer than that in the case where a plurality of cleaning members 53 are held. According to this embodiment, the number of cleaning holders 51 can be reduced, the required length of the linear member 54 can be shortened, and the manufacturing cost can be reduced.

Further, in the present embodiment, four tension pulleys 57 are rotatably held on the outer surface of the cover portion 12c. The four tension pulleys 57 are provided to stretch the linear member 54 into a predetermined annular shape. Further, the tension adjusting pulley 58 is rotatably held on the outer surface of the cover portion 12c. The linear member 54 is annularly stretched between the plurality of tension pulleys 57 and the tension adjusting pulleys 58. Specifically, the linear member 54 is stretched by four tensioning pulleys 57 between two adjacent transparent members 52 so as to be parallel to the longitudinal direction of each transparent member 52. The tension adjusting pulley 58 is an example of the tension adjusting mechanism. The tension adjusting pulley 58 is provided for adjusting the tension applied to the linear member 54. In this way, by using the rotatable pulleys 57 and 58 to stretch the linear member 54 in an annular shape, the linear member 54 can be smoothly run in an annular shape.

Further, the linear member 54 is wound around the take-up drum 59 many times, and the take-up motor 55 rotates the take-up drum 59, so that the linear member 54 runs in an annular shape. The take-up motor 55 and the take-up drum 59 are arranged in the recess 60 formed in the cover portion 12c. Specifically, the take-up drum 59 is rotatably held by the cover portion 12c in the recess 60. The take-up motor 55 is fixed to the cover portion 12c in the recess 60. The take-up motor 55 may be fixed to the accommodating portion 12b.

Further, each cleaning holder 51 is movably engaged with the cover portion 12c along the longitudinal direction of each transparent member 52. Hereinafter, an example of engagement between each cleaning holder 51 and the cover portion 12c will be described with reference to FIGS. 2 and 4.

As shown in FIGS. 2 and 4, in the present embodiment, two sets of a pair of guide rails (guide members) 61 are provided on the outer surface of the cover portion 12c corresponding to each cleaning holder 51. The pair of guide rails 61 is an example of the first guide member. Each guide rail 61 extends along the longitudinal direction of each transparent member 52, and both ends of each cleaning holder 51 (holding portion 51a) engage with a pair of corresponding guide rails 61. Each cleaning holder 51 is guided along the longitudinal direction of each transparent member 52 by a pair of corresponding guide rails 61. Therefore, each cleaning holder 51 can be stably moved along the longitudinal direction of each transparent member 52.

Further, each guide rail 61 is provided with a locking portion 61a that projects toward the corresponding cleaning holder 51. Each locking portion 61a extends along the longitudinal direction of each transmissive member 52. Both ends of the holding portion 51a of each cleaning holder 51 are locked to the locking portions 61a of the corresponding pair of guide rails 61 in the direction away from the housing 12a of the optical scanning device 12 (upward in FIG. 4). As a result, the upward movement (positional deviation) of each cleaning holder 51 is restricted. Further, each of the locking portions 61a can prevent the cleaning holder 51 from being detached from the cover portion 12c, and the corresponding cleaning member 53 can be stably brought into close contact with each of the transparent members 52. More preferably, each locking portion 61a is provided so that both ends of the holding portions 51a of each cleaning holder 51 are always in contact with the locking portions 61a of the corresponding pair of guide rails 61. As a result, each cleaning member 53 can be pressed against the corresponding transparent member 52. Therefore, each cleaning member 53 can be more stably adhered to the corresponding transparent member 52.

Further, in the present embodiment, two guide ribs (guide members) 62 are provided on the outer surface of the cover portion 12c corresponding to each cleaning holder 51. The guide rib 62 is an example of the second guide member. Each guide rib 62 extends between two adjacent transparent members 52 along the longitudinal direction of each transparent member 52. On the other hand, an engaging portion 63 is provided on the lower end side of each cleaning holder 51, and each engaging portion 63 engages with the corresponding guide rib 62. Therefore, each guide rib 62 guides the corresponding cleaning holder 51 along the longitudinal direction of each transparent member 52. As a result, each cleaning holder 51 can be stably moved along the longitudinal direction of each transparent member 52.

It is desirable that each guide rib 62 be arranged closer to the linear member 54. As a result, the swing of each cleaning holder 51 can be further suppressed during the cleaning process. That is, each cleaning holder 51 can be moved more stably along the longitudinal direction of each transparent member 52. More preferably, each guide rib 62 is provided directly below the linear member 54. As a result, the swing of each cleaning holder 51 during the cleaning process can be further suppressed.

In the present embodiment, the linear member 54 is connected to the upper end side of the holding portion 51a of each cleaning holder 51, and each engaging portion 63 is connected to the lower end side of the holding portion 51a of the corresponding cleaning holder 51. It is provided. As a result, the engaging portion between each guide rib 62 and each engaging portion 63 can be provided directly below the connecting portion between the corresponding cleaning holder 51 and the linear member 54.

Further, in the present embodiment, as shown in FIG. 4, each engaging portion 63 includes a pair of protruding portions 63a projecting downward from the corresponding cleaning holder 51, and each guide rib 62 includes a pair of corresponding protruding portions. It is sandwiched between 63a. Thereby, the movement of each cleaning holder 51 in the left-right direction can be restricted. Further, it is possible to limit the swing around the axis of each cleaning holder 51 extending in the vertical direction (the swing of each cleaning holder 51 in the moving direction).

Further, in the present embodiment, each guide rib 62 has a protruding portion 62b protruding from the cover portion 12c and a locking portion 62a projecting from the tip end portion of the protruding portion 62b. The locking portion 62a extends in the left direction (one direction in the extending direction of the holding portion 51a) from the tip end portion of the protruding portion 62b. On the other hand, each cleaning holder 51 extends in the right direction (the other direction in the extending direction of the holding portion 51a) from one protruding portion 63a of the pair of protruding portions 63a of each engaging portion 63, and locks the guide rib 62. It has a locking portion 63b that engages with the portion 62a. As a result, the upward movement of each cleaning holder 51 can be restricted. Further, it is possible to prevent the cleaning holder 51 from being detached from the cover portion 12c.

When both ends of the holding portions 51a of each cleaning holder 51 are always in contact with the locking portions 61a of the corresponding pair of guide rails 61, and each cleaning member 53 is brought into close contact with the corresponding transparent member 52. Each cleaning holder 51 may be deformed into a bow shape. When each cleaning holder 51 is deformed into a bow shape, each cleaning member 53 may be separated from the corresponding transparent member 52 on the central side of each cleaning holder 51. On the other hand, in the present embodiment, since the cover portion 12c includes the locking portion 62a and each cleaning holder 51 includes the locking portion 63b, when each cleaning holder 51 is deformed into an arch shape, the guide ribs 62 are engaged. The locking portion 63b of the corresponding cleaning holder 51 is locked to the stop portion 62a in the direction away from the housing 12a of the optical scanning device 12, whereby the bow-shaped deformation of each cleaning holder 51 is suppressed. As a result, the corresponding cleaning member 53 can be stably brought into close contact with each of the transparent members 52. More preferably, the locking portion 63b of the corresponding cleaning holder 51 (engaging portion 63) is locked to the locking portion 62a of each guide rib 62 below the position where each transparent member 52 is arranged. As a result, the effect of suppressing the deformation of the bow shape of each cleaning holder 51 can be enhanced.

FIG. 5 is a block diagram showing an example of a control path used in the image forming apparatus 1. Since various controls are performed for each part of the image forming apparatus 1 in using the image forming apparatus 1, the control path of the entire image forming apparatus 1 becomes complicated. Therefore, here, the part of the control path required for carrying out the present invention will be mainly described.

The voltage control circuit 71 is connected to the motor drive power supply 73, and operates the motor drive power supply 73 by an output signal from the control unit 90. The motor drive power supply 73 applies a predetermined drive voltage to the take-up motor 55 in the optical scanning device 12 by a control signal from the voltage control circuit 71. The current detection unit 75 detects the drive current that flows when a drive voltage is applied to the take-up motor 55.

The operation unit 80 is provided with a liquid crystal display unit 81 and LEDs 82 indicating various states, and is adapted to indicate the state of the image forming apparatus 1 and to display the image forming status and the number of printed copies. Various settings of the image forming apparatus 1 are performed from the printer driver of the personal computer.

The control unit 90 includes a CPU (Central Processing Unit) 91 as a central processing unit, a ROM (Read Only Memory) 92 as a read-only storage unit, a RAM (Random Access Memory) 93 as a read / write storage unit, and a timer. 95, At least an I / F (interface) 96 for transmitting a control signal to each device in the image forming device 1 and receiving an input signal from the operation unit 70 is provided.

The ROM 92 contains data such as a control program for the image forming apparatus 1 and numerical values necessary for control that are not changed during use of the image forming apparatus 1. The RAM 93 stores necessary data generated during the control of the image forming apparatus 1, data temporarily required for controlling the image forming apparatus 1, and the like. Further, the RAM 93 (or ROM 92) includes a voltage value (DUTY) applied to the take-up motor 55 and take-up in each operation mode of the cleaning holder 51, which will be described later, when the transparent member 52 of the optical scanning device 12 is cleaned. The driving time of the motor 55 and the like are also stored. The timer 95 measures the drive time of the take-up motor 55.

As described above, in the present embodiment, the take-up motor 55 is stopped when the second cleaning holder 512 comes into contact with the second stopper 56b. Therefore, tension (load) continues to be applied to the linear member 54 until the next cleaning operation is executed. As a result, the linear member 54 is stretched, and in the worst case, the linear member 54 may be broken.

Therefore, in the present embodiment, when the transparent member 52 is cleaned by the first cleaning holder 511 and the second cleaning holder 512 (hereinafter referred to as the cleaning mode), the first cleaning holder 511 and the second cleaning holder constituting the cleaning mode are formed. Following the reciprocating operation of 512, the load release operation is performed to release the load applied to the linear member 54 at the end of the cleaning mode. As a result, an inexpensive wire can be used as the linear member 54, and the service life of the linear member 54 can be extended. Hereinafter, the drive control of the take-up motor 55 in the cleaning mode will be described in detail.

FIG. 6 is a flowchart showing a first control example of drive control of the take-up motor 55 in the cleaning mode. A first control example of the take-up motor 55 will be described along the steps of FIG. 6 with reference to FIGS. 1 to 5 as necessary.

When the cleaning mode is started, the control unit 90 transmits a control signal to the voltage control unit 71, and supplies a drive voltage from the motor drive power supply 73 to the take-up motor 55. As a result, the take-up motor 55 is rotated forward in the first operation mode M1 (initial operation mode) (step S1). Here, the take-up motor 55 is driven and controlled by PWM (Pulse Width Modulation) control, and in the first operation mode M1, a drive voltage of 100% DUTY is supplied from the motor drive power supply 73. At the same time, the timer 95 starts measuring the drive time of the take-up motor 55.

Due to the forward rotation of the take-up motor 55, the linear member 54 travels in the direction of arrow D1 from the state shown in FIG. 2, the first cleaning holder 511 moves upward in FIG. 2, and the second cleaning holder 512 moves downward in FIG. Start moving to each.

Next, the control unit 90 determines whether or not the time T1 has elapsed from the start of the forward rotation of the take-up motor 55 (step S2). If the time T1 has not elapsed (No in step S2), the forward rotation of the take-up motor 55 in the first operation mode M1 is continued.

When the time T1 has elapsed (Yes in step S2), the control unit 90 transmits a control signal to the voltage control unit 71, and the forward rotation drive of the take-up motor 55 is performed with a drive torque higher than that of the first operation mode M1. Change to the smaller second operation mode M2 (final operation mode) (step S3). Specifically, the DUTY of the drive voltage supplied from the motor drive power supply 73 is changed from 100% to 70%.

As shown in FIG. 3, when the first cleaning holder 511 and the second cleaning holder 512 move to one end of the moving path, the first cleaning holder 511 comes into contact with the first stopper 56a. At this time, the load acting on the take-up motor 55 increases, and the drive current value flowing through the take-up motor 55 rises. Therefore, in the control unit 90, the drive current value detected by the current detection unit 75 is equal to or higher than the threshold value. Whether or not it is determined (step S4). If the drive current value is not equal to or higher than the threshold value (No in step S4), the forward rotation of the take-up motor 55 in the second operation mode M2 is continued.

If the drive current value is equal to or greater than the threshold value (Yes in step S4), it is determined that the first cleaning holder 511 and the second cleaning holder 512 have moved to one end of the movement path, and the control unit 90 determines that the voltage control unit 71 has moved. A control signal is transmitted to the take-up motor 55 to stop the forward rotation of the take-up motor 55 (step S5). As described above, the operation of steps S1 to S5 is the outbound operation by the first cleaning holder 511 and the second cleaning holder 512.

Next, the control unit 90 transmits a control signal to the voltage control unit 71, and supplies a drive voltage from the motor drive power supply 73 to the take-up motor 55. As a result, the take-up motor 55 is rotated in the reverse direction in the first operation mode M1 (step S6). Specifically, a drive voltage of 100% DUTY is supplied from the motor drive power supply 73. At the same time, the timer 95 starts measuring the drive time of the take-up motor 55.

Due to the reverse rotation of the take-up motor 55, the linear member 54 travels in the direction of arrow D2 from the state shown in FIG. 3, the first cleaning holder 511 moves downward in FIG. 3, and the second cleaning holder 512 moves upward in FIG. Start moving to each.

Next, the control unit 90 determines whether or not the time T1 has elapsed from the start of the reverse rotation of the take-up motor 55 (step S7). If the time T1 has not elapsed (No in step S7), the reverse rotation of the take-up motor 55 in the first operation mode M1 is continued.

When the time T1 has elapsed (Yes in step S7), the control unit 90 transmits a control signal to the voltage control unit 71, and the reverse rotation drive of the take-up motor 55 is driven by a drive torque higher than that of the first operation mode M1. Change to the smaller second operation mode M2 (step S8). Specifically, the DUTY of the drive voltage supplied from the motor drive power supply 73 is changed from 100% to 70%.

As shown in FIG. 2, when the first cleaning holder 511 and the second cleaning holder 512 move to the other end of the moving path, the second cleaning holder 512 comes into contact with the second stopper 56b. At this time, the load acting on the take-up motor 55 increases, and the drive current value flowing through the take-up motor 55 rises. Therefore, in the control unit 90, the drive current value detected by the current detection unit 75 is equal to or higher than the threshold value. Whether or not it is determined (step S9). If the drive current value is not equal to or greater than the threshold value (No in step S9), the reverse rotation of the take-up motor 55 in the second operation mode M2 is continued.

If the drive current value is equal to or greater than the threshold value (Yes in step S9), it is determined that the first cleaning holder 511 and the second cleaning holder 512 have moved to the other end of the movement path, and the control unit 90 determines that the voltage control unit 90 has moved. A control signal is transmitted to 71 to stop the reverse rotation of the take-up motor 55 (step S10). As described above, the operation of steps S6 to S10 is the return operation by the first cleaning holder 511 and the second cleaning holder 512.

Next, the control unit 90 transmits a control signal to the voltage control unit 71, and supplies a drive voltage from the motor drive power supply 73 to the take-up motor 55. As a result, the take-up motor 55 is rotated forward in the third operation mode M3 (step S11). Specifically, a drive voltage of 100% DUTY is supplied from the motor drive power supply 73. At the same time, the timer 95 starts measuring the drive time of the take-up motor 55.

Next, the control unit 90 determines whether or not the time T2 has elapsed from the start of the forward rotation of the take-up motor 55 (step S12). If the time T2 has not elapsed (No in step S12), the forward rotation of the take-up motor 55 in the third operation mode M3 is continued.

When the time T2 has elapsed (Yes in step S12), the forward rotation of the take-up motor 55 in the third operation mode M3 is stopped. The operations of steps S11 to S13 are load release operations for releasing the tension (load) of the linear member 54 after the return path operation.

According to the first control example shown in FIG. 6, after the return operation is completed, the load release operation of moving the first cleaning holder 511 and the second cleaning holder 512 by a predetermined amount in the outward direction is performed to perform the second operation. The cleaning holder 512 can be stopped in a state of being separated from the second stopper 56b. Therefore, it is possible to avoid a state in which tension (load) is continuously applied to the linear member 54, and it is possible to suppress elongation and breakage of the linear member 54 even when an inexpensive wire is used as the linear member 54.

Further, since the magnitudes of the drive torques of the first operation mode M1, the second operation mode M2, and the third operation mode M3 are in the order of M1, M3> M2, the drive when the load release operation is started is started. The torque is always larger than the drive torque at the end of the return operation. Therefore, it is possible to avoid a problem that the take-up motor 55 is locked at the start of the load release operation.

In steps S4 and S9 of FIG. 6, the forward rotation and the reverse rotation of the take-up motor 55 in the second operation mode M2 are continued depending on whether or not the drive current value detected by the current detection unit 75 is equal to or higher than the threshold value. Although it is determined whether or not to do so, the drive voltage value may be detected instead of the drive current value, and it may be determined whether or not the drive voltage value is equal to or greater than the threshold value.

FIG. 7 is a flowchart showing a second control example of drive control of the take-up motor 55 in the cleaning mode. In the second control example shown in FIG. 7, the second operation mode M2 of the first control example shown in FIG. 6 is terminated by the passage of time T2 (steps S4 and S9), and the third operation mode M3 is set to time T3. (Step S12). The other steps are the same as in the first control example.

According to the second control example, since the end of the second operation mode M2 in the outward path operation and the return path operation of the first cleaning holder 511 and the second cleaning holder 512 is determined by the drive time of the take-up motor 55, the take-up motor It is not necessary to detect the drive current value and the drive voltage value of 55. However, in order to suppress variations in the stop positions of the first cleaning holder 511 and the second cleaning holder 512, the first stopper 56a and the second stopper 56b are provided as shown in FIGS. 2 and 3.

Also in the second control example shown in FIG. 7, the second cleaning holder 512 can be stopped in a state of being separated from the second stopper 56b by performing the load release operation in the same manner as in the first control example. .. Therefore, it is possible to avoid a state in which tension (load) is continuously applied to the linear member 54, and it is possible to suppress elongation and breakage of the linear member 54 even when an inexpensive wire is used as the linear member 54.

FIG. 8 is a cross-sectional view of a part of the cover portion 12c of the optical scanning device 12 as viewed from a direction orthogonal to the moving direction of the cleaning holder 51. In FIG. 8, L1 and L2 indicate the outermost angle rays emitted from the laser light source (not shown) of the scanning optical system 120, and the region between the intersections of L1 and L2 and the transmissive member 52 is the ray emission range. It is R.

In the first control example and the second control example described above, when changing from the first operation mode M1 to the second operation mode M2, when the operation mode switching position overlaps with the light emission range R shown in FIG. Since the moving speed of the first cleaning holder 511 and the second cleaning holder 512 is slowed down at the position, or the first cleaning holder 511 and the second cleaning holder 512 stop momentarily due to control restrictions, wiping with the cleaning member 53 There is a risk of residue. Therefore, the time T1 is set so that the switching position of the operation mode does not overlap with the light ray emitting range R. In the second control example, by setting T1 <T2, the first operation mode M1 and the second operation mode M2 are switched before the first cleaning holder 511 and the second cleaning holder 512 reach the light ray emitting range R. ..

Further, the relationship between the times T1, T2 and T3 is T3 <T1 and T2. The reason for this is that when the stop positions of the first cleaning holder 511 and the second cleaning holder 512 overlap the light emission range R shown in FIG. 8 at the end of the load release operation (third operation mode M3), the light emission range R is emitted from the scanning optical system 120. This is because the generated laser light is blocked by the first cleaning holder 511 and the second cleaning holder 512, and a part of the image may be lost. Therefore, the duration T3 of the third operation mode M3 is shortened, and the first cleaning holder 511 and the second cleaning holder 512 are stopped before the light ray emitting range R.

By the way, in the first control example and the second control example described above, the DUTY of the drive voltage applied to the take-up motor 55 in the third operation mode M3 which is the load release operation is the same as that of the first operation mode M1 (100%). ). In this case, while there is an advantage that the take-up motor 55 can be prevented from being locked at the start of the third operation mode M3, the drive torque is too strong and the first cleaning holder 511 at the end of the third operation mode M3, The stop position of the second cleaning holder 512 may overshoot and fall into the light emitting range R (see FIG. 8).

Therefore, in order to reliably avoid overshooting the stop positions of the first cleaning holder 511 and the second cleaning holder 512, the DUTY of the drive voltage applied to the take-up motor 55 in the third operation mode M3 is set to the second operation mode M2. It can also be the same as (70%). In this case, the take-up motor 55 may be locked at the start of the third operation mode M3, but is driven by the first operation mode M1 having a large drive torque at the start of the next cleaning mode (outward route operation). Therefore, there is no possibility that the take-up motor 55 will be locked.

Others The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the above embodiment, a tandem color printer has been described as an example of the image forming apparatus 1, but the present invention is not limited to the color printer, but may be applied to an electrophotographic color image forming apparatus such as a color copier or a facsimile. Applicable.

Further, it can be applied not only to a color image forming apparatus but also to an electrophotographic type monochrome image forming apparatus such as a monochrome printer and a monochrome multifunction device. In the case of the monochrome image forming apparatus, since there is only one photoconductor drum, the optical scanning apparatus 12 has one emission port of the laser light emitted from the scanning optical system 120 to the photoconductor drum. Therefore, there is only one transparent member 52 that seals the outlet.

FIG. 9 is a plan view showing a moving mechanism of the cleaning holder 51 in the optical scanning device 12 used in the monochrome image forming device. As shown in FIG. 9, one cleaning holder 51 that reciprocates along the transparent member 52 is provided, and the linear member 54 is fixed at the center in the width direction orthogonal to the moving direction of the cleaning holder 51. Then, the cleaning member 53 is held at a position facing the transparent member 52 on one end side in the width direction of the cleaning holder 51, and the guide rail 61 is extended to the other end side in the width direction of the cleaning holder 51. A first stopper 56a and a second stopper 56b are arranged on one end side (upper end side) and the other end side (lower end side) of the cleaning holder 51 in the moving direction, respectively.

Also in the configuration of FIG. 9, by driving the take-up motor 55 according to the first and second control examples described above, it is possible to avoid a state in which tension (load) continues to be applied to the linear member 54. In the case of the first control example, since the cleaning holder 51 needs to be in contact with the stoppers at the end of the outward path operation and the return path operation, the first stoppers 56a and the second stopper 56a are on both ends in the moving direction of the cleaning holder 51. It is necessary to arrange the stopper 56b.

Further, in the above embodiment, the first stopper 56a and the second stopper 56b move along the transparent member 52 in the outward path operation, and following the outward path operation, the first stopper 56a and the second stopper 56b move in the opposite directions to the outward path operation. Although the example of executing the cleaning mode with the return operation of moving to and one cycle is described, the cleaning mode can be configured with only one outbound operation or only one return operation. Even in that case, it is possible to avoid a state in which tension (load) continues to be applied to the linear member 54 by performing the load release operation after the end of the outward path operation or the end of the return path operation.

Further, the material, shape, and the like of each component shown in the above embodiment are merely examples and are not particularly limited, and various changes can be made without substantially deviating from the effects of the present invention. For example, in the above embodiment, the tensioning pulley 57 in which the linear member 54 is stretched in an annular shape is used, but instead of the tensioning pulley 57, a plurality of protrusions are provided on the outer surface of the cover portion 12c. The linear member 54 may be provided and may be bridged over each protrusion. Similarly, as the tension adjusting mechanism, at least one protrusion may be provided on the outer surface of the cover portion 12c instead of the tension adjusting pulley 58. Further, the tension adjusting mechanism and the take-up drum 59 may be omitted.

The present invention can be used in an optical scanning device that irradiates an image carrier with light to form an electrostatic latent image. By utilizing the present invention, an optical scanning device capable of suppressing elongation or breakage of a linear member due to continuous load applied to the linear member when the cleaning holder for cleaning a transparent member transmitting laser light is stopped, and an optical scanning device thereof. An image forming apparatus including the above can be provided.

1 Image forming device 11a to 11d Photoreceptor drum 12 Optical scanning device 12a Housing 12b Accommodating part 12c Cover part 51 Cleaning holder 511 First cleaning holder 512 Second cleaning holder 52 Transparent member 53 Cleaning member 34 Linear member 55 Winding Motor (drive unit)
56a 1st stopper 56b 2nd stopper 57 Pulley for tensioning 58 Pulley for tension adjustment 73 Motor drive power supply (drive voltage power supply)
75 Current detection unit 90 Control unit 95 Timer (time measurement unit)
120 scanning optics

Claims (11)

An optical scanning device that irradiates an image carrier with laser light to form an electrostatic latent image.
A housing in which an outlet for the laser beam extending in the main scanning direction of the laser beam is formed corresponding to the image carrier.
A transmissive member having transparency to the laser beam, extending in the main scanning direction of the laser beam, and sealing the emission port of the laser beam.
A linear member stretched in an annular shape on the housing,
A drive unit that causes the linear member to travel in the first direction and the second direction,
A cleaning holder that is fixed to the linear member and moves in the extending direction of the transparent member when the linear member is annularly driven by the driving unit.
A cleaning member that is fixed to the cleaning holder and slides with respect to the transparent member as the cleaning holder moves to clean the transparent member.
A stopper arranged at the end of the movement path of the cleaning holder and restricting the movement of the cleaning holder,
A control unit that controls the drive of the drive unit,
With
The control unit
By moving the linear member in the first direction, the cleaning holder moves along the extending direction of the transparent member, and the outbound operation.
After executing the outbound operation, the cleaning holder moves in the opposite direction to the outbound operation by moving the linear member in the second direction, and a return operation.
It is possible to perform a cleaning mode that includes at least one of the
An optical scanning apparatus characterized in that after the execution of the cleaning mode, a load release operation of moving the cleaning holder by a predetermined amount in a direction opposite to the outward path operation or the return path operation, which is the final operation of the cleaning mode, is executed. The outbound operation and the return operation include two or more operation modes in which the drive torque of the drive unit is different, and the load release operation is compared with the final operation mode set at the end of the outbound operation and the return operation. The optical scanning apparatus according to claim 1, further comprising one operation mode in which the drive torque of the drive unit is large. The outward path operation and the return path operation include two or more operation modes in which the drive torque of the drive unit is different, and the load release operation is a final operation mode and the drive set at the end of the outward path operation and the return path operation. The optical scanning apparatus according to claim 1, wherein the optical scanning apparatus has one operation mode in which the drive torques of the units are the same. The optical scanning apparatus according to claim 2, wherein the duration of the operation mode in the load release operation is shorter than that of all the operation modes in the cleaning mode. The optical scanning apparatus according to claim 4, wherein the control unit stops the drive unit at a timing when the cleaning holder is outside the light emitting range of the transparent member at the end of the load release operation. .. The initial operation mode set at the start of the outward path operation and the return path operation is according to any one of claims 2 to 5, wherein the drive torque of the drive unit is larger than that of the final operation mode. Optical scanning device. 2. The control unit is characterized in that switching between the operation modes in the outbound operation and the inbound operation is executed at a timing when the cleaning holder is outside the light emitting range of the transmissive member. The optical scanning apparatus according to any one of claims 6. A drive voltage power supply that supplies a drive voltage to the drive unit is provided.
The second to seventh aspects of the invention, wherein the control unit adjusts the drive torque of each of the operation modes during the cleaning mode and in the load release operation by changing the DUTY of the drive voltage. Optical scanning device. A detection unit that detects the current value or voltage value that flows when the drive voltage is supplied to the drive unit is provided.
When the current value or the voltage value detected by the detection unit becomes larger than a predetermined value, the control unit determines that the cleaning holder has come into contact with the stopper, and determines that the outbound operation or the inbound operation The optical scanning apparatus according to any one of claims 1 to 8, wherein the drive unit is stopped at the end of the above-mentioned method. A housing in which a plurality of laser beam outlets extending in the main scanning direction of the laser beam are arranged side by side corresponding to the plurality of image carriers.
The plurality of transmissive members that block the plurality of laser beam outlets, respectively,
As the cleaning holder, a first cleaning holder and a second cleaning holder that move along the extending direction of the transparent member when the linear member is annularly traveled by the driving unit.
As the stopper, a first stopper which is arranged at one end of the transmissive member in the extending direction and regulates the movement of the first cleaning holder to the one side,
A second stopper arranged at one end of the transparent member in the extending direction and restricting the movement of the second cleaning holder to the one side,
With
In the outbound operation, the first cleaning holder moves to the one side, the second cleaning holder moves to the other side in the direction opposite to the one side, and in the return operation, the first cleaning holder moves to the other side. The optical scanning apparatus according to any one of claims 1 to 9, wherein the second cleaning holder moves to the one side. With one or more of the image carriers
An image forming apparatus comprising the optical scanning apparatus according to any one of claims 1 to 10, wherein the image carrier is irradiated with laser light to form an electrostatic latent image.