JP7310384B2 - OPTICAL SCANNER AND IMAGE FORMING APPARATUS INCLUDING THE SAME - Google Patents

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 equipped with the optical scanning device.

2. Description of the Related Art An image forming apparatus such as a copier or a printer that employs an electrophotographic method is provided with an optical scanning device. The optical scanning device irradiates a 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 section with an opening on one side and a cover section that covers the opening. A scanning optical system is incorporated inside the accommodating portion, and the cover portion is formed with an exit opening for light emitted from the scanning optical system corresponding to the image carrier. Furthermore, the exit port is covered with a transparent member. The transmissive member is a member that transmits light emitted from the scanning optical system.

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

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

Further, in Patent Document 2, two cleaning holders each holding two cleaning members are connected to a linear member, and the two cleaning holders move along the permeable member as the linear member travels circularly. Also disclosed is an optical scanning device in which each cleaning member slides over a corresponding transmissive member. Further, it is described that the cleaning holder comes into contact with the stopper at one end of the moving path, thereby stopping the traveling of the linear member.

Japanese Patent Application Laid-Open No. 2009-143108 JP 2016-31467 A

In the configuration of Patent Document 2, after the cleaning holder is reciprocated, it is stopped in a state of 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 performed. As a result, the linear member is elongated, and in the worst case, the linear member may break.

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides an optical scanning device capable of suppressing elongation and breakage of a linear member due to continuous load applied to the linear member when the cleaning holder is stopped, and an image forming apparatus having the same. intended to provide

In order to achieve the above object, a first configuration of the present invention is an optical scanning device for forming an electrostatic latent image by irradiating an image carrier with laser light, comprising: a housing; a shape member, a driving portion, a cleaning holder, a cleaning member, a stopper, and a control portion. The housing is formed with a laser light exit opening extending in the main scanning direction of the laser light corresponding to the image carrier. The transmissive member has transparency to the laser beam, extends in the main scanning direction of the laser beam, and seals the exit port of the laser beam. The linear member is annularly stretched around the housing. The driving section 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 permeable member when the linear member is circularly traveled by the drive unit. The cleaning member is fixed to the cleaning holder, and cleans the permeable member by sliding against the permeable member as the cleaning holder moves. The stopper is arranged at the end of the moving path of the cleaning holder and regulates the movement of the cleaning holder. The control section controls driving of the driving section. The controller causes the linear member to travel in the first direction, thereby causing the cleaning holder to move along the extending direction of the transparent member. By running, it is possible to execute a cleaning mode including at least one of an outward movement and a return movement in which the cleaning holder moves in the opposite direction. After executing the cleaning mode, the control unit executes a load release operation for moving the cleaning holder by a predetermined amount in a direction opposite to the forward movement or the return movement, which is the final movement of the cleaning mode.

According to the first configuration of the present invention, after the cleaning mode is executed, the load release operation is performed to move the cleaning holder in the opposite direction by a predetermined amount, so that the cleaning holder can be stopped while being separated from the stopper. 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.

FIG. 1 is a cross-sectional view schematically showing the overall configuration of an image forming apparatus 1 in which an optical scanning device 12 of the present invention is mounted; FIG. 2 is a plan view showing the cover portion 12c of the optical scanning device 12 according to one embodiment of the present invention; 4 is a plan view for explaining the operation of the cleaning holder 51 provided on the cover portion 12c in the optical scanning device 12 of the present embodiment; FIG. 5 is a cross-sectional view of a portion of the cover portion 12c in the optical scanning device 12 of the present embodiment, viewed from the moving direction of the cleaning holder 51; FIG. 1 is a block diagram showing an example of a control path used in the image forming apparatus 1; FIG. Flowchart showing a first control example of drive control of the winding motor 55 in the cleaning mode Flowchart showing a second control example of drive control of the winding motor 55 in the cleaning mode FIG. 4 is a cross-sectional view of a part of the cover portion 12c of the optical scanning device 12 of the present embodiment, viewed from a direction orthogonal to the moving direction of the cleaning holder 51; 2 is a plan view showing a moving mechanism of a cleaning holder 51 in an optical scanning device 12 used in a monochrome image forming apparatus; FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view schematically showing the overall configuration of an image forming apparatus 1 in which an optical scanning device of the present invention is mounted. The image forming apparatus 1 is a tandem color printer. The image forming apparatus 1 includes rotatable photosensitive drums 11a to 11d as image carriers. For the photoreceptor drums 11a to 11d, an organic photoreceptor (OPC photoreceptor) on which an organic photoreceptor layer is formed, an amorphous silicon photoreceptor on which an amorphous silicon photoreceptor layer is formed, or the like is used. The photoreceptor 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 photosensitive drum 11a. Similarly, developing devices 2b to 2d, chargers 13b to 13d and cleaning devices 14b to 14d are arranged around the respective photosensitive drums 11b to 11d. An optical scanning device 12 is arranged below the developing devices 2a to 2d. In this specification, "bottom" and "top" refer to "bottom" and "top" in the drawings.

The developing devices 2a-2d are arranged on the right side of the photosensitive drums 11a-11d, respectively. The developing devices 2a to 2d face the photosensitive drums 11a to 11d, respectively, and supply toner to the photosensitive drums 11a to 11d. In this specification, right and left refer to right and left in the drawings.

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

The optical scanning device 12 emits light onto the surfaces of the photosensitive drums 11a to 11d, which are 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. are irradiated (optically scanned) to form electrostatic latent images on the surfaces of the photosensitive drums 11a to 11d.

A housing 12a of the optical scanning device 12 includes a housing portion 12b having an opening on one side and a cover portion 12c covering the opening. A scanning optical system 120 is incorporated inside the accommodating portion 12b. The cover portion 12c is formed with outlets for light (laser light) emitted from the scanning optical system 120 corresponding to the photosensitive drums 11a to 11d. Furthermore, as will be described later, each exit port is covered with a transparent member 52 (see FIG. 2). The transmissive member 52 is transmissive to light emitted from the scanning optical system 120 .

Scanning optics 120 includes a laser light source (not shown) and a polygon mirror. The scanning optical system 120 also includes at least one reflecting mirror and a lens corresponding to each of the photosensitive drums 11a to 11d. A laser beam emitted from a laser light source passes through a polygon mirror, a group of reflecting mirrors, and a group of lenses, from the downstream side of the chargers 13a to 13d in the rotation direction of the photosensitive drums 11a to 11d. The surface of 11d is irradiated respectively. As a result, electrostatic latent images are formed on the surfaces of the photosensitive drums 11a to 11d. These electrostatic latent images are developed into toner images by developing devices 2a to 2d.

An endless intermediate transfer belt 17 is stretched around a tension roller 6 , a driving roller 25 and a driven roller 27 . As the drive roller 25 is rotated by a motor (not shown), the intermediate transfer belt 17 is driven to circulate clockwise in FIG.

The photoreceptor drums 11a to 11d are arranged below the intermediate transfer belt 17 so as to be adjacent to each other along the conveying direction (the arrow direction in FIG. 1). Further, the photosensitive drums 11a to 11d are in contact with the intermediate transfer belt 17 respectively. The primary transfer rollers 26a-26d face the photosensitive drums 11a-11d, respectively, with the intermediate transfer belt 17 interposed therebetween. The primary transfer rollers 26a-26d are pressed against the intermediate transfer belt 17, respectively, and form a primary transfer portion together with the photosensitive drums 11a-11d. A toner image is transferred to the intermediate transfer belt 17 at these primary transfer portions. Specifically, by applying a primary transfer voltage to the primary transfer rollers 26a to 26d, the toner images on the photosensitive drums 11a to 11d are sequentially transferred to the intermediate transfer belt 17 at predetermined timings. As a result, a full-color toner image is formed on the surface of the intermediate transfer belt 17 by superimposing four color toner images of magenta, cyan, yellow, and black in 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 and forms a secondary transfer portion together with the driving roller 25 . In this secondary transfer portion, the toner image on the surface of the intermediate transfer belt 17 is transferred to the paper P by applying a 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 disposed below the image forming apparatus 1 . The paper feed cassette 32 can accommodate a plurality of sheets of paper P. As shown in FIG. A stack tray 35 for manual paper feeding is arranged on the right side of the paper feeding 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 drawn out from the paper feed cassette 32 to the secondary transfer portion. A second paper transport path 36 is arranged to the left of the stack tray 35 . The second paper transport path 36 transports the paper drawn out from the stack tray 35 to the secondary transfer portion. Furthermore, a fixing section 18 and a third paper transport path 39 are arranged in the upper left part of the image forming apparatus 1 . The fixing section 18 performs a fixing process on the paper P on which the image is formed. The third paper transport path 39 transports the paper P on which the fixing process has been performed to the paper discharge section 37 .

The paper P stored in the paper feed cassette 32 is delivered one by one to the first paper transport path 33 side by a pick-up roller 33b and a separating roller pair 33a.

The first paper transport path 33 and the second paper transport path 36 join before (on the upstream side of) the registration roller pair 33c. The registration roller pair 33c conveys the paper P to the secondary transfer portion at the timing of the image forming operation on the intermediate transfer belt 17 and the feeding operation to the secondary transfer portion. The full-color toner image on the intermediate transfer belt 17 is secondarily transferred onto the sheet P conveyed to the secondary transfer portion by the secondary transfer roller 34 to which the secondary transfer voltage is applied. The paper P onto which the full-color toner image has been transferred is conveyed to the fixing section 18 .

The fixing unit 18 includes a fixing belt heated by a heater, a fixing roller in contact with the fixing belt, a pressure roller in pressure contact with the fixing roller with the fixing belt interposed therebetween, and the like. The fixing section 18 heats and presses the paper P onto which the toner image has been transferred. Thus, the fixing process is performed. The sheet P on which the toner image is fixed in the fixing section 18 is turned upside down in the fourth sheet conveying path 40 if necessary. After that, the paper P is again conveyed to the secondary transfer section via the pair of registration rollers 33 c , and a new toner image is secondarily transferred to the back surface of the paper P by the secondary transfer roller 34 and fixed by the fixing section 18 . be. The paper P on which the toner image is fixed passes through the third paper conveying path 39 and is discharged to the paper discharge section 37 by the discharge roller pair 19 .

Next, the optical scanning device 12 will be described with reference to FIGS. 2, 3, and 4. FIG. FIG. 2 is a plan view showing the cover portion 12c of the optical scanning device 12. As shown in FIG. 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 as seen from the moving direction of the cleaning holder 51, and is a front view of the cleaning holder 51. As shown in FIG.

As described above, the housing 12a of the optical scanning device 12 includes the housing portion 12b and the cover portion 12c attached to the housing portion 12b. Correspondingly, four laser beam exit openings are arranged side by side. Each emission port has a rectangular shape elongated in the main scanning direction of the corresponding laser beam, and each emission port is formed such that the longitudinal directions thereof are parallel to each other. Each exit port is sealed with a rectangular plate-shaped transparent member 52 . The four transmissive members 52 are arranged side by side so that their longitudinal directions are parallel to each other. Each transparent member 52 is provided to prevent toner, dust, and the like from entering the optical scanning device 12 . Each transparent member 52 is, for example, a glass cover.

The optical scanning device 12 has 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 51 a extends across two adjacent transmissive members 52 and holds two cleaning members 53 . Each cleaning holder 51 is provided on the outer surface (surface on the side of the photosensitive drums 11a to 11d) of the cover portion 12c. Each cleaning member 53 is held by each holding portion 51 a so as to be arranged corresponding to each transmissive member 52 . Each cleaning member 53 is, for example, a rubber pad. Silicon rubber, for example, can be used as the material of the rubber pad. Each cleaning holder 51 is made of resin, for example. Note that each cleaning member 53 is not limited to a rubber pad, and may be, for example, a nonwoven fabric.

Each cleaning holder 51 is connected to a linear member 54 that is annularly stretched so as to pass between two adjacent transmissive members 52 . The linear member 54 travels in a loop by the driving force of the winding motor 55, which is the driving portion. The linear member 54 is, for example, a wire.

The four cleaning members 53 slide on the outer surfaces of the four transmissive members 52 (surfaces on the side of the photosensitive drums 11a to 11d) as the linear members 54 travel in a circular fashion. Thereby, the outer surface of each permeable member 52 is simultaneously cleaned by the corresponding cleaning member 53 .

The winding motor 55 can rotate forward and backward. This makes it possible to repeatedly perform the cleaning process for each transmissive member 52 . In the present embodiment, the winding motor 55 is rotated forward and reverse in one cleaning process to reciprocate the corresponding cleaning member 53 along the longitudinal direction of each transmissive 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 host device such as a personal computer while the image forming apparatus 1 is in the maintenance mode. be. Also, the cleaning process may be performed periodically, for example, every time printing (image formation) of about 10,000 sheets is performed.

In this embodiment, as the linear member 54 travels circularly, the first cleaning holder 511 and the second cleaning holder 512 move in opposite directions along the longitudinal direction of each transmissive member 52 (the main scanning direction of the laser beam). move in a straight line. A first stopper 56 a is provided at one end of the moving path of the first cleaning holder 511 , and a second stopper 56 b 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 of each transmissive member 52 in the longitudinal direction between two adjacent transmissive members 52 . When the first cleaning holder 511 or the second cleaning holder 512 moves to one end of its movement path and contacts the corresponding first stopper 56a or second stopper 56b, the linear member 54 stops running. When the linear member 54 stops traveling and the load acting on the winding motor 55 increases, the rotation direction of the winding motor 55 is reversed or the operation of the winding motor 55 stops. Resin, for example, 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 made 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. FIG. In this embodiment, as described above, the corresponding cleaning member 53 reciprocates once along the longitudinal direction of each transmissive member 52 in one cleaning process. Here, a case will be described where the running direction of the linear member 54 changes from the direction indicated by arrow D1 (first direction) to the direction indicated by arrow D2 (second direction) during the cleaning process.

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. abut. As a result, the linear member 54 stops traveling, and the first cleaning holder 511 and the second cleaning holder 512 stop. At this time, the load acting on the winding motor 55 increases.

In response to this increase in load, the rotation direction of the winding motor 55 is reversed, and the linear member 54 travels in the second direction (opposite to the first direction) indicated by 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 its movement path. touch. As a result, the linear member 54 stops traveling, and the operations of the first cleaning holder 511 and the second cleaning holder 512 stop. At this time, the load acting on the winding motor 55 increases. In response to this load increase, the winding motor 55 stops.

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

Further, in this embodiment, four tensioning pulleys 57 are rotatably held on the outer surface of the cover portion 12c. Four tensioning pulleys 57 are provided to tension the linear member 54 into a predetermined annular shape. A tension adjusting pulley 58 is rotatably held on the outer surface of the cover portion 12c. The linear member 54 is annularly stretched between a plurality of tension pulleys 57 and tension adjustment pulleys 58 . Specifically, the linear member 54 is stretched between two adjacent permeable members 52 by four tensioning pulleys 57 so as to be parallel to the longitudinal direction of each permeable member 52 . The tension adjusting pulley 58 is an example of a tension adjusting mechanism. A tension adjusting pulley 58 is provided to adjust 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 a loop, the linear member 54 can be made to run smoothly in a loop.

The linear member 54 is wound around the winding drum 59 many times, and the winding drum 59 is rotated by the winding motor 55 so that the linear member 54 travels circularly. The winding motor 55 and the winding drum 59 are arranged in a recess 60 formed in the cover portion 12c. Specifically, the winding drum 59 is rotatably held in the recess 60 by the cover portion 12c. The winding motor 55 is fixed to the cover portion 12c within the recess 60. As shown in FIG. Note that the winding motor 55 may be fixed to the housing portion 12b.

Further, each cleaning holder 51 is engaged with the cover portion 12c so as to be movable along the longitudinal direction of each transparent member 52. As shown in FIG. An example of engagement between each cleaning holder 51 and the cover portion 12c will be described below with reference to FIGS. 2 and 4. FIG.

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

Further, each guide rail 61 is provided with a locking portion 61 a projecting toward the corresponding cleaning holder 51 . Each locking portion 61 a extends along the longitudinal direction of each transparent member 52 . Both ends of the holding portion 51a of each cleaning holder 51 are engaged with the engaging 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 direction in FIG. 4). As a result, the upward movement (positional deviation) of each cleaning holder 51 is restricted. Further, each locking portion 61a can prevent each cleaning holder 51 from being detached from the cover portion 12c, and can stably bring the corresponding cleaning member 53 into close contact with each transparent member 52. As shown in FIG. More preferably, each locking portion 61a is provided so that both end portions of the holding portion 51a of each cleaning holder 51 are always in contact with the corresponding locking portions 61a of the pair of guide rails 61, respectively. Thereby, each cleaning member 53 can be pressed against the corresponding transparent member 52 . Therefore, it becomes possible to bring each cleaning member 53 into close contact with the corresponding transmissive member 52 more stably.

Further, in the present embodiment, two guide ribs (guide members) 62 are protruded from the outer surface of the cover portion 12c corresponding to each cleaning holder 51. As shown in FIG. The guide rib 62 is an example of a second guide member. Each guide rib 62 extends between two adjacent transmissive members 52 along the longitudinal direction of each transmissive 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 . Thereby, each cleaning holder 51 can be stably moved along the longitudinal direction of each transmissive member 52 .

Each guide rib 62 is desirably arranged at a position closer to the linear member 54 . This makes it possible to further suppress the swinging of each cleaning holder 51 during the cleaning process. That is, each cleaning holder 51 can be moved more stably along the longitudinal direction of each transmissive member 52 . More preferably, each guide rib 62 is provided directly below the linear member 54 . As a result, swinging of the cleaning holders 51 during the cleaning process can be further suppressed.

In this embodiment, the linear member 54 is connected to the upper end side of the holding portion 51 a of each cleaning holder 51 , and each engaging portion 63 is connected to the lower end side of the holding portion 51 a of the corresponding cleaning holder 51 . is provided. Thereby, the engaging portions of the guide ribs 62 and the engaging portions 63 can be provided directly below the connecting portions of the corresponding cleaning holders 51 and the linear members 54 .

Further, in this embodiment, as shown in FIG. 4, each engaging portion 63 includes a pair of projecting portions 63a projecting downward from the corresponding cleaning holder 51, and each guide rib 62 includes a pair of corresponding projecting portions. 63a. Thereby, the lateral movement of each cleaning holder 51 can be restricted. In addition, swinging of each cleaning holder 51 about the axis extending in the vertical direction (swinging of each cleaning holder 51 in the moving direction) can be restricted.

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

When both end portions of the holding portion 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 transmissive member 52, Each cleaning holder 51 can deform into an arcuate shape. When each cleaning holder 51 deforms into an arc, each cleaning member 53 may separate from the corresponding permeable member 52 on the central side of each cleaning holder 51 . On the other hand, in the present embodiment, the cover portion 12c has the locking portion 62a and each cleaning holder 51 has the locking portion 63b. The locking portion 63b of the corresponding cleaning holder 51 is locked to the stopping portion 62a in the direction away from the housing 12a of the optical scanning device 12, thereby suppressing the arcuate deformation of each cleaning holder 51. As shown in FIG. As a result, the corresponding cleaning member 53 can be stably brought into close contact with each transparent member 52 . More preferably, the engaging portion 62a of each guide rib 62 engages the engaging portion 63b of the corresponding cleaning holder 51 (engaging portion 63) below the position where each transparent member 52 is arranged. As a result, the effect of suppressing arcuate deformation of each cleaning holder 51 can be enhanced.

FIG. 5 is a block diagram showing an example of control paths used in the image forming apparatus 1. As shown in FIG. Since various parts of the apparatus are controlled when the image forming apparatus 1 is used, the overall control path of the image forming apparatus 1 is complicated. Therefore, here, the portion of the control path that is necessary for implementing 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 according to the output signal from the control section 90 . A motor driving power supply 73 applies a predetermined driving voltage to the winding motor 55 in the optical scanning device 12 according to a control signal from the voltage control circuit 71 . The current detection section 75 detects the drive current that flows when the drive voltage is applied to the winding motor 55 .

An operation unit 80 is provided with a liquid crystal display unit 81 and LEDs 82 for indicating various states, and is adapted to indicate the state of the image forming apparatus 1, the image forming state, and the number of copies to be printed. 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 readable and writable storage unit, and a timer. 95 , and at least an I/F (interface) 96 for transmitting control signals to each device in the image forming apparatus 1 and for receiving input signals from the operation unit 70 .

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

As described above, in this embodiment, the winding motor 55 is stopped when the second cleaning holder 512 contacts the second stopper 56b. Therefore, tension (load) continues to be applied to the linear member 54 until the next cleaning operation is performed. As a result, the linear member 54 is elongated, and in the worst case, the linear member 54 may break.

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 cleaning mode), the first cleaning holder 511 and the second cleaning holder that constitute the cleaning mode After the reciprocating motion 512, the load releasing motion 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. Drive control of the winding motor 55 in the cleaning mode will be described in detail below.

FIG. 6 is a flow chart showing a first control example of driving control of the winding motor 55 in the cleaning mode. A first control example of the winding motor 55 will be described along the steps of FIG. 6 while referring to FIGS. 1 to 5 as necessary.

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

2, the first cleaning holder 511 moves upward in FIG. 2, and the second cleaning holder 512 moves downward in FIG. to and start moving respectively.

Next, the control unit 90 determines whether or not the time T1 has elapsed since the winding motor 55 started to rotate forward (step S2). If the time T1 has not elapsed (No in step S2), the forward rotation of the winding motor 55 is continued in the first operation mode M1.

If the time T1 has passed (Yes in step S2), the control unit 90 transmits a control signal to the voltage control unit 71 to drive the winding motor 55 in the forward rotation with a higher drive torque than in the first operation mode M1. It changes to the small 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 movement path, the first cleaning holder 511 contacts the first stopper 56a. At this time, the load acting on the winding motor 55 increases and the driving current value flowing through the winding motor 55 increases. It is determined whether or not (step S4). If the drive current value is not equal to or greater than the threshold value (No in step S4), the forward rotation of the winding motor 55 is continued in the second operation mode M2.

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 controls the voltage control unit 71. to stop the forward rotation of the winding motor 55 (step S5). The operations of steps S 1 to S 5 described above are forward movement operations 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 drive voltage from the motor drive power supply 73 to the winding motor 55 . As a result, the winding motor 55 is reversely rotated in the first operation mode M1 (step S6). Specifically, a drive voltage with a duty of 100% is supplied from the motor drive power supply 73 . At the same time, the timer 95 starts measuring the driving time of the winding motor 55 .

3, the first cleaning holder 511 moves downward in FIG. 3, and the second cleaning holder 512 moves upward in FIG. to and start moving respectively.

Next, the control unit 90 determines whether or not the time T1 has elapsed since the reverse rotation of the winding motor 55 was started (step S7). If the time T1 has not elapsed (No in step S7), the reverse rotation of the winding motor 55 is continued in the first operation mode M1.

If the time T1 has passed (Yes in step S7), the control unit 90 transmits a control signal to the voltage control unit 71 to drive the winding motor 55 in the reverse rotation with a higher drive torque than in the first operation mode M1. It changes to the small 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 movement path, the second cleaning holder 512 contacts the second stopper 56b. At this time, the load acting on the winding motor 55 increases and the driving current value flowing through the winding motor 55 increases. It is determined whether or not (step S9). If the driving current value is not equal to or greater than the threshold value (No in step S9), the reverse rotation of the winding motor 55 is continued in the second operation mode M2.

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 controls the voltage control unit 71 to stop the reverse rotation of the winding motor 55 (step S10). The operations in steps S6 to S10 described above are the return operations by the first cleaning holder 511 and the second cleaning holder 512. FIG.

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

Next, the control unit 90 determines whether or not the time T2 has elapsed since the winding motor 55 started to rotate forward (step S12). If the time T2 has not elapsed (No in step S12), the forward rotation of the winding motor 55 is continued in the third operation mode M3.

If the time T2 has elapsed (Yes in step S12), the forward rotation of the winding motor 55 in the third operation mode M3 is stopped. The operations of steps S11 to S13 are load releasing operations for releasing the tension (load) of the linear member 54 after the backward movement.

According to the first control example shown in FIG. 6, after the return movement is completed, the load release operation is performed to move the first cleaning holder 511 and the second cleaning holder 512 in the forward movement direction by a predetermined amount. The cleaning holder 512 can be stopped in a state 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 even when an inexpensive wire is used as the linear member 54, the linear member 54 can be prevented from being stretched or broken.

In addition, since the magnitude of the driving torque in the first operation mode M1, the second operation mode M2, and the third operation mode M3 is in the order of M1, M3>M2, the driving torque when starting the load release operation is The torque is always greater than the drive torque at the end of the return motion. Therefore, it is possible to avoid the problem that the winding motor 55 is locked when the load releasing operation is started.

Note that in steps S4 and S9 of FIG. 6, the forward and reverse rotation of the winding motor 55 in the second operation mode M2 is continued depending on whether or not the drive current value detected by the current detection unit 75 is equal to or greater than the threshold value. Although it is determined whether or not to drive, the drive voltage value may be detected instead of the drive current value, and determination may be made based on whether or not the drive voltage value is equal to or greater than the threshold value.

FIG. 7 is a flow chart showing a second control example of drive control of the winding 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. (step S12). Other steps are the same as in the first control example.

According to the second control example, the end of the second operation mode M2 in the outward movement and return movement of the first cleaning holder 511 and the second cleaning holder 512 is determined based on the drive time of the winding motor 55. The detection of the driving current value and the driving voltage value of 55 becomes unnecessary. However, in order to suppress variations in stop positions of the first cleaning holder 511 and the second cleaning holder 512, a first stopper 56a and a second stopper 56b are provided as shown in FIGS.

In the second control example shown in FIG. 7 as well, by performing the load releasing operation as in the first control example, the second 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 even when an inexpensive wire is used as the linear member 54, the linear member 54 can be prevented from being stretched or broken.

FIG. 8 is a cross-sectional view of a portion of the cover portion 12c of the optical scanning device 12 as seen from a direction perpendicular to the moving direction of the cleaning holder 51. As shown in FIG. 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 area between the intersections of L1 and L2 and the transmissive member 52 is the light emission range. 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, if the switching position of the operation mode overlaps the light beam emission range R shown in FIG. At this position, the moving speed of the first cleaning holder 511 and the second cleaning holder 512 is decelerated, or the first cleaning holder 511 and the second cleaning holder 512 stop momentarily due to control restrictions, so that the cleaning member 53 does not wipe. Leftovers may occur. Therefore, the time T1 is set so that the operation mode switching position does not overlap the light emission range R. FIG. In the second control example, by setting T1<T2, the operation mode is switched from the first operation mode M1 to the second operation mode M2 before the first cleaning holder 511 and the second cleaning holder 512 reach the light emission range R. .

The relationship between times T1, T2 and T3 is T3<T1, 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 beam emission range R shown in FIG. This is because the emitted laser light may be 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 to stop the first cleaning holder 511 and the second cleaning holder 512 before the light beam emission 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 winding motor 55 in the third operation mode M3, which is the load release operation, is the same as in the first operation mode M1 (100% ). In this case, there is an advantage that the winding motor 55 can be prevented from being locked at the start of the third operation mode M3. There is a risk that the stop position of the second cleaning holder 512 will overshoot and overlap with the light emission range R (see FIG. 8).

Therefore, in order to reliably avoid the overshoot of the stop positions of the first cleaning holder 511 and the second cleaning holder 512, the DUTY of the drive voltage applied to the winding motor 55 in the third operation mode M3 is set to the second operation mode M2. can be the same as (70%). In this case, the winding motor 55 may be locked at the start of the third operation mode M3, but at the start of the next cleaning mode (forward movement), it is driven in the first operation mode M1 with a large drive torque. Therefore, there is no possibility that the winding motor 55 will be locked.

In addition, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the present invention. For example, in the above-described embodiment, a tandem color printer was described as an example of the image forming apparatus 1, but the present invention is not limited to color printers, and is applicable to electrophotographic color image forming apparatuses such as color copiers and facsimiles. Applicable.

In addition, the present invention is applicable not only to color image forming apparatuses but also to electrophotographic monochrome image forming apparatuses such as monochrome printers and monochrome multifunction peripherals. In the case of a monochrome image forming apparatus, since there is one photosensitive drum, the optical scanning device 12 has one exit port for laser light emitted from the scanning optical system 120 to the photosensitive drum. Therefore, there is also only one transmissive member 52 that seals the exit port.

FIG. 9 is a plan view showing the moving mechanism of the cleaning holder 51 in the optical scanning device 12 used in the monochrome image forming apparatus. As shown in FIG. 9, one cleaning holder 51 that reciprocates along the permeable member 52 is provided, and a linear member 54 is fixed at the center in the width direction orthogonal to the moving direction of the cleaning holder 51 . The cleaning member 53 is held at a position facing the permeable member 52 on one widthwise end of the cleaning holder 51 , and the guide rail 61 extends on the other widthwise end 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.

In the configuration of FIG. 9 as well, by driving the winding motor 55 according to the first and second control examples described above, it is possible to avoid a state in which tension (load) is continuously applied to the linear member 54 . In the case of the first control example, it is necessary for the cleaning holder 51 to be in contact with the stoppers at the end of the outward movement and the return movement. It is necessary to arrange the stopper 56b.

Further, in the above-described embodiment, the first stopper 56a and the second stopper 56b move along the permeable member 52 in the outward motion, and following the outward motion, the first stopper 56a and the second stopper 56b move in the direction opposite to the outward motion. Although an example in which the cleaning mode is performed with one cycle of the backward movement of moving to and the cleaning mode, it is also possible to configure the cleaning mode with only one forward movement or only one return movement. Even in that case, by performing a load releasing operation after the forward movement or after the return movement, it is possible to avoid a state in which tension (load) is continuously applied to the linear member 54 .

Also, the material, shape, etc. of each component shown in the above embodiment are examples and are not particularly limited, and various changes are possible within the scope of the effects of the present invention. For example, in the above-described embodiment, the tensioning pulley 57 for annularly tensioning the linear member 54 is used. may be provided, and the linear member 54 may be bridged over each projection. Similarly, as the tension adjusting mechanism, instead of the tension adjusting pulley 58, at least one protrusion may be provided on the outer surface of the cover portion 12c. Also, the tension adjusting mechanism and the winding drum 59 can be omitted.

INDUSTRIAL APPLICABILITY The present invention can be used for an optical scanning device that irradiates an image carrier with light to form an electrostatic latent image. By using the present invention, an optical scanning device capable of suppressing elongation and breakage of a linear member due to continuous load applied to the linear member when a cleaning holder that cleans a transparent member that transmits laser light is stopped, and the same. can be provided.

1 image forming apparatus 11a to 11d photoreceptor drum 12 optical scanning device 12a housing 12b housing portion 12c cover portion 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 First stopper 56b Second 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 optical system

Claims (8)

An optical scanning device that forms an electrostatic latent image by irradiating an image carrier with laser light,
a housing in which an emission port for the laser light extending in the main scanning direction of the laser light is formed corresponding to the image carrier;
a transparent member that has transparency to the laser beam, extends in the main scanning direction of the laser beam, and seals an exit port of the laser beam;
a linear member that is annularly stretched around the housing;
a driving unit that causes the linear member to travel in a first direction and a second direction;
a cleaning holder that is fixed to the linear member and moves in the extending direction of the permeable member when the linear member is circularly traveled by the drive unit;
a cleaning member that is fixed to the cleaning holder and that cleans the permeable member by sliding on the permeable member as the cleaning holder moves;
a stopper arranged at the end of the movement path of the cleaning holder and restricting the movement of the cleaning holder;
a drive voltage power supply that supplies a drive voltage to the drive unit;
a control unit that controls driving of the drive unit;
with
The control unit
an outward motion in which the cleaning holder moves along the extending direction of the permeable member by causing the linear member to travel in the first direction;
a return movement in which the cleaning holder moves in a direction opposite to the outward movement by causing the linear member to travel in the second direction after execution of the outward movement;
is capable of executing a cleaning mode including at least one of
After executing the cleaning mode, executing a load release operation of moving the cleaning holder by a predetermined amount in a direction opposite to the forward movement or the return movement, which is the final movement of the cleaning mode ,
The outward movement and the return movement include two or more operation modes with different driving torques of the drive unit, and the load release operation includes a final operation mode set at the end of the outward movement and the return movement and the driving mode. drive torque is the same, and in the forward movement and the return movement, which are the cleaning modes subsequent to the load releasing operation, the driving torque is greater than that in the load releasing operation, and the first operation mode is driven. An optical scanning device characterized by: 2. The optical scanning device according to claim 1 , wherein a duration of said operation mode in said load releasing operation is shorter than all of said operation modes in said cleaning mode . 3. The optical scanning device according to claim 2, wherein the control unit stops the driving unit at a timing when the cleaning holder is out of the light beam emission range of the transparent member when the load releasing operation is finished. . 3. The control unit switches between the respective operation modes in the outward movement and the return movement at a timing when the cleaning holder is out of a light beam emission range of the transparent member. 4. The optical scanning device according to claim 3. 5. The controller according to any one of claims 1 to 4, wherein the control unit adjusts the drive torque in each of the operation modes during the cleaning mode and during the load release operation by changing the duty of the drive voltage. The optical scanning device according to . A detection unit that detects a current value or a voltage value that flows when the drive voltage is supplied to the drive unit,
The controller determines that the cleaning holder has come into contact with the stopper when the current value or the voltage value detected by the detector becomes larger than a predetermined value, and performs the outward movement or the homeward movement. 6. The optical scanning device according to any one of claims 1 to 5, wherein the driving section is stopped when the scanning is completed . the housing in which a plurality of laser light exit openings extending in a main scanning direction of the laser light are arranged in parallel so as to correspond to the plurality of image carriers;
a plurality of the transmissive members that respectively block the plurality of laser light exit ports;
a first cleaning holder and a second cleaning holder as the cleaning holders, which move along the extending direction of the transparent member when the linear member is circularly traveled by the drive unit;
a first stopper, as the stopper, which is arranged at one end of the permeable member in the extending direction and restricts movement of the first cleaning holder to the one side;
a second stopper disposed at one end in the extending direction of the permeable member and restricting movement of the second cleaning holder to the one side;
with
In the outward movement, the first cleaning holder moves to the one side, and the second cleaning holder moves to the other side opposite to the one side, and in the returning movement, the first cleaning holder moves to the other side. 7. The optical scanning device according to claim 1 , wherein said second cleaning holder moves to said one side . one or more of the image carriers;
8. The optical scanning device according to claim 1, wherein the image carrier is irradiated with a laser beam to form an electrostatic latent image;
image forming apparatus .

Images