Optical scanning device and image forming apparatus equipped with the same

Abstract

An optical scanning device (12) comprises: a housing (12a); transparent members (52); a linear member (54); a drive unit (55); guide rails (61); a pair of cleaning holders (511); cleaning members (53); a detection unit (56); and a control unit (90). The control unit (90) controls the driving of the drive unit (55). When the detection unit detects that one of the cleaning holders (511) has reached one end of a movement path of the cleaning holders (511) while a cleaning mode is in execution, the control unit (90) initiates an outward-trip operation, whereas when the detection unit (56) detects that the other of the cleaning holders (511) has reached the one end of the movement path of the cleaning holders (511), the control unit initiates a return-trip operation.

Description

[Technical Field]

[0001] The present invention relates to an optical scanning device that forms an electrostatic latent image by irradiating light onto an image carrier in an electrophotographic image forming apparatus, and to an image forming apparatus equipped with an optical scanning device. [Background technology]

[0002] Conventionally, optical scanning devices have been disclosed (see, for example, Patent Document 1). This optical scanning device irradiates a charged image carrier with light to form an electrostatic latent image on the image carrier. The optical scanning device includes a housing, a transparent member, a linear member, a driving member, a guide rail, a cleaning holder, a cleaning member, and a stopper.

[0003] The housing has a laser beam exit opening formed therein, the exit opening extending in the main scanning direction of the laser beam irradiated onto the image carrier. The transparent member extends in the main scanning direction of the laser beam and seals the laser beam exit opening. The spiral member extends in the extending direction of the transparent member. The guide rail is arranged in parallel with the exit opening and extends in the extending direction of the transparent member.

[0004] The cleaning holders are connected to the linear member, and the two cleaning holders move along the permeable member as the linear member moves in a circular motion. The cleaning members are fixed to the cleaning holders, and clean the permeable member by sliding against it as the cleaning holder moves. The cleaning holders come into contact with a stopper at one end of their movement path, stopping the movement of the linear member. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-31467 Summary of the Invention [Problem to be solved by the invention]

[0006] In conventional optical scanning devices, the cleaning holder is stopped in abutment with a stopper when switching from forward movement to backward movement, which places a large tension (load) on the linear member, causing the problem of damage to the gears that support the linear member so that it can move in a circular motion.

[0007] SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide an optical scanning device capable of reducing the load on a linear member, and an image forming apparatus including the same. [Means for solving the problem]

[0008] In order to achieve the above object, a first configuration of the present invention is an optical scanning device that forms an electrostatic latent image by irradiating an image carrier with laser light, and includes a housing, a transparent member, a linear member, a drive unit, a guide rail, a pair of cleaning holders, a cleaning member, a detection unit, and a control unit. The housing has a plurality of laser light emission openings that extend in the main scanning direction of the laser light corresponding to the image carrier. The transparent member is transparent to the laser light, extends in the main scanning direction of the laser light, and seals the laser light emission openings. The linear member is stretched in a ring shape on the housing. The drive unit causes the linear member to travel in a first direction and a second direction. The guide rail is arranged juxtaposed to the emission openings and extends in the extension direction of the transparent member. The pair of cleaning holders are fixed to the linear member and move in opposite directions on adjacent transparent members along the guide rail when the linear member is driven to travel in a ring shape by the drive unit. The cleaning member is fixed to the cleaning holder and cleans the transparent member by sliding against it as the cleaning holder moves. The detection unit is disposed on one side of the extending direction of the transparent member and detects when the cleaning holder reaches one end of the cleaning holder's movement path. The control unit controls the driving of the drive unit. The control unit is capable of executing a cleaning mode including an outward movement and a return movement. In the outward movement, the linear member is moved in a first direction, causing the cleaning holder to move along the extending direction of the transparent member. In the return movement, after the outward movement is executed, the linear member is moved in a second direction, causing the cleaning holder to move in the opposite direction to the outward movement. During execution of the cleaning mode, the outward movement is initiated when the detection unit detects that one side of the cleaning holder has reached one end of the cleaning holder's movement path, and the return movement is initiated when the detection unit detects that the other side of the cleaning holder has reached one end of the cleaning holder's movement path. [Effects of the Invention]

[0009] According to the first configuration of the present invention, the load applied to the linear member can be reduced. [Brief explanation of the drawings]

[0010] [Figure 1]FIG. 1 is a cross-sectional view showing a schematic overall configuration of an image forming apparatus 1 equipped with an optical scanning device 12 according to the present invention. [Figure 2] 1 is a perspective view of an optical scanning device 12 according to an embodiment of the present invention; [Figure 3] FIG. 1 is an enlarged perspective view showing a portion of an optical scanning device 12 according to an embodiment of the present invention. [Figure 4] FIG. 1 is an enlarged perspective view showing a portion of an optical scanning device 12 according to an embodiment of the present invention. [Figure 5] 1 is a cross-sectional view showing a part of the optical scanning device 12 according to an embodiment of the present invention, viewed from the direction of movement of the cleaning holder 511. [Figure 6] FIG. 1 is a plan view schematically illustrating an optical scanning device 12 according to an embodiment of the present invention. [Figure 7] FIG. 1 is a plan view schematically illustrating an optical scanning device 12 according to an embodiment of the present invention. [Figure 8] FIG. 1 is a perspective view schematically illustrating a part of an optical scanning device 12 according to an embodiment of the present invention. [Figure 9] FIG. 1 is a perspective view schematically illustrating a part of an optical scanning device 12 according to an embodiment of the present invention. [Figure 10] FIG. 1 is a block diagram showing an example of a control path used in an image forming apparatus 1 according to an embodiment of the present invention. [Figure 11] 1 is a flowchart showing a first example of drive control of the winding motor 55 in the cleaning mode. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a schematic overall configuration of an image forming apparatus 1 equipped with an optical scanning device of the present invention. The image forming apparatus 1 is a tandem color printer. The image forming apparatus 1 is equipped with rotatable photosensitive drums 11a to 11d as image carriers. The photosensitive drums 11a to 11d are made of organic photosensitive materials (OPC photosensitive materials) having an organic photosensitive layer formed thereon, or amorphous silicon photosensitive materials having an amorphous silicon photosensitive layer formed thereon. The photosensitive drums 11a to 11d are arranged in tandem corresponding to the colors magenta, cyan, yellow, and black.

[0012] Developing device 2a, charger 13a, and cleaning device 14a are disposed around photosensitive drum 11a. Similarly, developing devices 2b to 2d, chargers 13b to 13d, and cleaning devices 14b to 14d are disposed around photosensitive drums 11b to 11d, respectively. In addition, optical scanning device 12 is disposed below developing devices 2a to 2d.

[0013] The developing devices 2a to 2d are disposed to the right of the photosensitive drums 11a to 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 the right and left in the drawings.

[0014] The chargers 13a to 13d are disposed upstream of the developing devices 2a to 2d in the direction of rotation of the photosensitive drums 11a to 11d, and face the surfaces of the photosensitive drums 11a to 11d, respectively. The chargers 13a to 13d uniformly charge the surfaces of the photosensitive drums 11a to 11d, respectively.

[0015] The optical scanning device 12 irradiates (optical scans) the surfaces of the photosensitive drums 11a to 11d, which have been uniformly charged by the chargers 13b to 13d, with light based on image data such as characters and pictures input to an image input unit from a personal computer or the like, and forms electrostatic latent images on the surfaces of the photosensitive drums 11a to 11d.

[0016] The housing 12a of the optical scanning device 12 includes a storage section 12b with one surface open, and a cover section 12c that covers the opening. The storage section 12b incorporates a scanning optical system 120 therein. The cover section 12c is formed with exit openings 12d (see FIG. 4) through which light (laser light) is emitted from the scanning optical system 120 corresponding to the photosensitive drums 11a to 11d. Furthermore, as will be described later, each of the exit openings 12d is covered with a transparent member 52. The transparent member 52 is transparent to the light emitted from the scanning optical system 120.

[0017] The scanning optical system 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. Laser light emitted from the laser light source is irradiated onto the surfaces of the photosensitive drums 11a to 11d from downstream of the chargers 13a to 13d in the rotation direction of the photosensitive drums 11a to 11d, via the polygon mirror, the reflecting mirror group, and the lens group. 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 the developing devices 2a to 2d.

[0018] An endless intermediate transfer belt 17 is stretched over a tension roller 6, a drive 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 driven to circulate in the clockwise direction in FIG.

[0019] The photosensitive drums 11a to 11d are arranged adjacent to each other along the transport direction (the direction of the arrow in FIG. 1) below the intermediate transfer belt 17. The photosensitive drums 11a to 11d are in contact with the intermediate transfer belt 17. The primary transfer rollers 26a to 26d face the photosensitive drums 11a to 11d, respectively, with the intermediate transfer belt 17 sandwiched therebetween. The primary transfer rollers 26a to 26d are each pressed against the intermediate transfer belt 17 and form a primary transfer portion together with the photosensitive drums 11a to 11d. At this primary transfer portion, toner images are transferred onto the intermediate transfer belt 17. More specifically, a primary transfer voltage is applied to the primary transfer rollers 26a to 26d, so that the toner images on the photosensitive 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 on the surface of the intermediate transfer belt 17, in which toner images of four colors, magenta, cyan, yellow, and black, are superimposed in a predetermined positional relationship.

[0020] The secondary transfer roller 34 faces the drive roller 25 with the intermediate transfer belt 17 sandwiched therebetween. The secondary transfer roller 34 is pressed against the intermediate transfer belt 17 and forms a secondary transfer section together with the drive roller 25. In this secondary transfer section, a secondary transfer voltage is applied to the secondary transfer roller 34, so that the toner image on the surface of the intermediate transfer belt 17 is transferred to the paper P. After the toner image is transferred, a belt cleaning device 31 cleans off any toner remaining on the intermediate transfer belt 17.

[0021] A paper feed cassette 32 is disposed at the bottom within the image forming apparatus 1. The paper feed cassette 32 can store multiple sheets of paper P. A stack tray 35 for manual paper feed is disposed to the right of the paper feed cassette 32. A first paper transport path 33 is disposed to the left of the paper feed cassette 32. The first paper transport path 33 transports paper P fed from the paper feed cassette 32 to the secondary transfer unit. A second paper transport path 36 is disposed to the left of the stack tray 35. The second paper transport path 36 transports paper fed from the stack tray 35 to the secondary transfer unit. Furthermore, a fixing unit 18 and a third paper transport path 39 are disposed at the upper left within the image forming apparatus 1. The fixing unit 18 performs a fixing process on paper P on which an image has been formed. The third paper transport path 39 transports paper P after the fixing process to a paper discharge unit 37.

[0022] The sheets P stored in the sheet cassette 32 are fed one by one to the first sheet transport path 33 by a pickup roller 33b and a pair of separating rollers 33a.

[0023] The first paper transport path 33 and the second paper transport path 36 merge before (upstream from) the pair of registration rollers 33c. The pair of registration rollers 33c transports the paper P to the secondary transfer unit in accordance with the timing of the image formation 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 onto the paper P transported to the secondary transfer unit by the secondary transfer roller 34 to which a secondary transfer voltage is applied. The paper P to which the full-color toner image has been transferred is transported to the fixing unit 18.

[0024] The fixing unit 18 includes a fixing belt heated by a heater, a fixing roller in contact with the inside of the fixing belt, and a pressure roller that is pressed against the fixing roller across the fixing belt. The fixing unit 18 heats and presses the paper P onto which the toner image has been transferred, thereby carrying out the fixing process. The paper P onto which the toner image has been fixed in the fixing unit 18 is turned over as necessary in the fourth paper transport path 40. The paper P is then transported again to the secondary transfer unit via the registration roller pair 33c, and a new toner image is secondarily transferred onto the back side of the paper P by the secondary transfer roller 34, and fixed in the fixing unit 18. The paper P with the fixed toner image passes through the third paper transport path 39 and is discharged to the paper discharge unit 37 by the discharge roller pair 19.

[0025] Next, the optical scanning device 12 will be described with reference to Figs. 2 to 6. Fig. 2 is a perspective view of the optical scanning device 12. Figs. 3 and 4 are enlarged perspective views of a portion of the optical scanning device 12. Fig. 5 is a cross-sectional view schematically showing a portion of the optical scanning device 12 from the movement direction of the cleaning holder 511. Figs. 6 and 7 are plan views schematically showing the optical scanning device 12.

[0026] In the following drawings, the extension direction of the transparent member 52 is defined as the X direction, with X1 representing one side of the extension direction of the transparent member 52 approaching the detection unit 56 and X2 representing the other side of the extension direction of the transparent member 52 moving away from the detection unit 56. The parallel direction of the transparent member 52 is defined as the Y direction, with Y1 representing one side of the parallel direction of the transparent member 52 and Y2 representing the other side of the extension direction of the transparent member 52. Also, in FIG. 2, the shapes and positional relationships of the various parts will be described assuming that the cleaning holders 511 and 512 are on top of the cover portion 12c. The terms "upper" and "lower" are used merely for the purpose of explanation and do not limit the orientation of the optical scanning device 12 when incorporated into the image forming apparatus 1.

[0027] The optical scanning device 12 includes a housing 12a, a transparent member 52, a linear member 54, a motor (drive unit) 55, a guide rail 61, a stopper 62, cleaning holders 511 and 512, a cleaning member 53, a detection unit 56, and a control unit 90 (see FIG. 10).

[0028] Housing 12a includes a storage section 12b and a cover section 12c attached to storage section 12b, and cover section 12c has four laser beam outlets 12d (see FIG. 5) arranged side by side in correspondence with four photosensitive drums 11a to 11d. Each outlet 12d has a rectangular shape that is long in the main scanning direction (X direction) of the corresponding laser beam, and each outlet 12d is formed so that its longitudinal direction (X direction) is parallel to one another.

[0029] The transparent members 52 are formed in the shape of rectangular plates and seal each of the emission openings 12d. This prevents toner, dust, and the like from entering the interior of the optical scanning device 12 through each of the emission openings 12d. The four transparent members 52 are arranged side by side so that their longitudinal directions (X direction) are parallel to each other. Each transparent member 52 is, for example, a glass cover.

[0030] The guide rails 61 are arranged in pairs on both sides of the pair of transparent members 52. That is, four guide rails 61 are arranged side by side. The guide rails 61 protrude from the upper surface of the cover portion 12c and extend in the extension direction (X direction) of the transparent members 52. The guide rails 61 have guide ribs 61a that protrude outward from the tip end and extend in the extension direction (X direction) of the transparent members 52 (see FIG. 5).

[0031] The stoppers 62 are arranged on one side (X1 side) in the extension direction of the guide rails 61, and restrict movement of the cleaning holders 511, 512 to one side (X1 side) in the extension direction. The stoppers 62 are fixed to the upper surface of the cover portion 12c. In this embodiment, the stoppers 62 are provided on one side of the two guide rails 61 that the cleaning holders 511, 512 straddle, and extend in the parallel direction (Y direction) of the permeable member 52.

[0032] The cleaning holders 511 and 512 are disposed on the upper surface of the cover 12c (the surface facing the photosensitive drums 11a to 11d) and include a main body 51a, an engaging portion 51b, and light-shielding portions 511a and 512a. The main body 51a is formed in a plate shape and extends in the parallel direction (Y direction) of the transparent members 52 so as to straddle the space between two adjacent transparent members 52.

[0033] The cleaning members 53 are fixed to the lower surface of the main body 51a (see FIG. 5). A pair of cleaning members 53 are arranged inside the engaging portion 51b in the parallel direction (Y direction). As the linear members 54 travel in an annular motion, each cleaning member 53 slides on the upper surface of each transparent member 52 (the surface facing the photosensitive drums 11a to 11d). As a result, the upper surfaces of each transparent member 52 are simultaneously cleaned by the corresponding cleaning members 53.

[0034] The cleaning members 53 are, for example, rubber pads. The material of the rubber pads can be, for example, silicone rubber. Each of the cleaning holders 511, 512 is formed from, for example, resin. Note that each of the cleaning members 53 is not limited to rubber pads and may be, for example, nonwoven fabric.

[0035] A pair of engagement portions 51b are arranged on both sides of the pair of guide rails 61. The engagement portions 51b protrude downward from the bottom surface of the main body portion 51a, with their tips bent toward the adjacent guide rail 61. The engagement portions 51b engage with the guide ribs 61a. The cleaning holders 511, 512 are guided along the corresponding pair of guide rails 61. This allows the cleaning holders 511, 512 to move stably on each transparent member 52 in the extension direction (X direction).

[0036] Furthermore, the engaging portion 51b engages with the guide rib 61a, and both ends of the main body 51a are locked to the guide rail 61 in the direction away from the housing 12a of the optical scanning device 12 (upward in FIG. 5). This restricts the upward movement (misalignment) of the cleaning holders 511 and 512, preventing them from detaching from the cover 12c. Therefore, the cleaning members 53 can be stably attached to each transparent member 52.

[0037] Also, the other end (X2 side) of the guide rail 61 in the extension direction (X direction) is open (see FIGS. 6 and 7). This allows the cleaning holders 511, 512 to be easily incorporated into the guide rail 61 by sliding the cleaning holders 511, 512 from the other end of the guide rail 61 in the extension direction to one side (X1 side) of the guide rail 61 while engaging the engaging portion 51b with the guide rib 61a. This improves the ease of assembly of the optical scanning device 12.

[0038] The engaging portion 51b and the guide rib 61a are an example of the engagement between the cleaning holders 511 and 512 and the cover portion 12c, and the present invention is not limited to this structure.

[0039] The light shielding portion 511a is arranged at a side end portion on one side (Y1 side) in the parallel direction of the main body portion 51a of the cleaning holder 511, and protrudes to one side in the extension direction (X1 direction) (see FIGS. 6 and 7). The light shielding portion 512a is arranged at a side end portion on the other side (Y2 side) in the parallel direction of the main body portion 51a of the cleaning holder 512, and protrudes to one side in the extension direction (X1 direction) (see FIGS. 6 and 7). The shapes of the light shielding portion 511a and the light shielding portion 512a will be described in detail later.

[0040] The main body 51a has a recess 51c recessed downward from the top surface, and the linear member 54 fits into the recess 51c. The recess 51c also has a protrusion 51d protruding inward from the inner surface, and the provision of the protrusion 51d causes the linear member 54 to bend within the recess 51c. This firmly fixes the cleaning holders 511 and 512 to the linear member 54. The recess 51c may also be recessed upward from the bottom surface of the main body 51a.

[0041] The linear member 54 may be, for example, a timing belt or a wire. The linear member 54 passes between two transparent members 52 in the housing 12a and is stretched in a ring shape between four tensioning pulleys 57. The linear member 54 extends between two adjacent transparent members 52 in a direction parallel to the extension direction (X direction) of each transparent member 52. The four tensioning pulleys 57 are rotatably held on the upper surface of the cover portion 12c.

[0042] One of the tensioning pulleys 57 is connected to a gear 57a arranged on the underside of the cover portion 12c (see FIGS. 6 and 7). The gear 57a is connected to a motor 55. The motor 55 rotates the gear 57a, causing the linear member 54 to travel in a circular motion.

[0043] The motor (drive unit) 55 is disposed outside the linear member 54 and is fixed to the lower surface of the cover portion 12c. That is, the upper end of the motor 55 is disposed lower than the upper end of the linear member 54. This saves space on the upper surface of the cover portion 12c. Furthermore, by disposing the motor 55 outside the linear member 54, maintenance of the motor 55 and the gear 57a is facilitated. The motor 55 is rotatable forward and backward. When driven by the motor 55, the linear member 54 moves circularly in a clockwise direction (direction D2) or counterclockwise direction (direction D1) in a top view (see FIGS. 6 and 7). This causes the cleaning holders 511 and 512 to reciprocate along the longitudinal direction of the transparent member 52 (the main scanning direction of the laser light). During this reciprocating movement, the cleaning holders 511 and 512 move linearly in opposite directions.

[0044] The cleaning process is executed when the image forming apparatus 1 is in the maintenance mode and the user inputs a process start command from the operation unit 80 (see FIG. 10) or a higher-level device such as a personal computer. The cleaning process may also be executed periodically, for example, every time approximately 10,000 sheets of printing (image formation) are performed.

[0045] The detection unit 56 is disposed on one side (X1 side) in the extension direction of the permeable member 52, and is disposed between the movement path of the cleaning holder 511 and the movement path of the cleaning holder 512 in the parallel direction (Y direction) of the permeable member 52 (see FIGS. 6 and 7). The detection unit 56 detects that one of the cleaning holders 511, 512 has reached one end of the movement path of the cleaning holders 511, 512. When the cleaning holders 511, 512 have reached one end of the movement path, they come into contact with a stopper 62, and their movement to one side (X1 side) in the extension direction is restricted.

[0046] The detection unit 56 is a sensor having a light-emitting unit 56a and a light-receiving unit 56b, and one sensor can detect that either the cleaning holder 511 or the cleaning holder 512 has reached one end of the movement path. The light-emitting unit 56a emits light in the parallel direction (Y direction) of the transparent member 52. The light-receiving unit 56b receives the light emitted from the light-emitting unit 56a. Note that, although the light-emitting unit 56a is arranged on one side (Y1 side) of the light-receiving unit 56b in the parallel direction in this embodiment, the light-emitting unit 56a may be arranged on the other side (Y2 side) of the light-receiving unit 56b in the parallel direction.

[0047] Next, the detection unit 56 and the light-blocking units 511a and 512a will be described with reference to Fig. 8 and Fig. 9. Fig. 8 and Fig. 9 are perspective views that schematically show the detection unit 56 and the light-blocking units 511a and 512a, with Fig. 8 showing the relationship between the detection unit 56 and the light-blocking unit 511a and Fig. 9 showing the relationship between the detection unit 56 and the light-blocking unit 512a.

[0048] The light-shielding portion 511a and the light-shielding portion 512a have different shapes. In this embodiment, the light-shielding portion 512a has through-holes 512b formed therein that penetrate in the parallel direction (Y direction) (see FIG. 9), but the light-shielding portion 511a does not have through-holes 512b formed therein (see FIG. 8).

[0049] As a result, when cleaning member holder 511 or cleaning member holder 512 reaches one end of the movement path, the light receiving pattern received by light receiving portion 56b differs between light blocking portion 511a and light blocking portion 512a.

[0050] Specifically, when the tip of the light-shielding portion 511a, which is moving toward one side in the extension direction (the X1 side), is inserted between the light-emitting portion 56a and the light-receiving portion 56b, the light emitted from the light-emitting portion 56a is blocked by the tip of the light-shielding portion 511a. As a result, the light-receiving portion 56b cannot receive the light emitted from the light-emitting portion 56a. At this time, the detection portion 56 is turned on. Furthermore, by moving the light-shielding portion 511a toward one side in the extension direction (the X1 side), the cleaning holder 511 reaches one end of the movement path and comes into contact with the stopper 62. As a result, the movement of the cleaning holder 511 toward the one side in the extension direction (the X1 side) is restricted. At this time, the light emitted from the light-emitting portion 56a is blocked by the light-shielding portion 511a, and the detection portion 56 is maintained in the on state (see FIG. 8).

[0051] On the other hand, when the tip of the light-shielding portion 512a, which is moving toward one side in the extension direction (the X1 side), is inserted between the light-emitting portion 56a and the light-receiving portion 56b, the light emitted from the light-emitting portion 56a is blocked by the tip of the light-shielding portion 512a. As a result, the light-receiving portion 56b cannot receive the light emitted from the light-emitting portion 56a. At this time, the detection portion 56 is turned on. Furthermore, by moving the light-shielding portion 512a toward one side in the extension direction (the X1 side), the cleaning holder 512 reaches one end of the movement path and comes into contact with the stopper 62. As a result, the movement of the cleaning holder 512 toward the one side in the extension direction (the X1 side) is restricted. At this time, the light emitted from the light-emitting portion 56a passes through the through-hole 512b and is received by the light-receiving portion 56b, and the detection portion 56 is switched off (see FIG. 9).

[0052] As a result, when the detection unit 56 remains on for a predetermined time while the cleaning mode is being executed, it can detect that the cleaning holder 511 has reached one end of its movement path. Furthermore, when the detection unit 56 remains on for a predetermined time while the cleaning mode is being executed and then switches to the off state, it can detect that the cleaning holder 512 has reached one end of its movement path. At this time, the linear member 54 stops traveling. That is, when one of the cleaning holders 511, 512 reaches one end of its movement path and its movement is restricted by the stopper 62, the other of the cleaning holders 511, 512 stops moving. This prevents the other of the cleaning holders 511, 512 from coming off the guide rail 61 on the other side (X2 side) of the extended direction of the opened guide rail 61.

[0053] 6 and 7, the operation of the cleaning holder 51 will be described. In this embodiment, as described above, in one cleaning process, the corresponding cleaning member 53 reciprocates once along the extension direction (X direction) of each permeable member 52. Here, a case will be described in which the traveling 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.

[0054] At the start of the cleaning process, the cleaning holder 511 turns on the detection unit 56 at one end of its movement path (see FIG. 6). By setting the state where the cleaning holder 511 is positioned at one end of its movement path as the initial position at the start of the cleaning mode, the detection unit 56 can detect the cleaning holder 511 in the on state. This makes it possible to prevent an initial error from occurring during the cleaning process.

[0055] When the cleaning process starts, the linear member 54 moves in the first direction indicated by arrow D1 (see FIG. 6). As a result, the cleaning holder 511 and the cleaning holder 512 move from the position shown in FIG. 6 to the position shown in FIG. 7, and the detection unit 56 detects that the cleaning holder 512 has reached one end of the movement path, causing the linear member 54 to stop moving. As a result, the cleaning holder 511 and the cleaning holder 512 stop.

[0056] Next, the rotation direction of the motor 55 is reversed, and the linear member 54 travels in a second direction (opposite to the first direction) indicated by arrow D2 (see FIG. 7). As a result, the cleaning holder 511 and the cleaning holder 512 move from the position shown in FIG. 7 to the position shown in FIG. 6, and the detection unit 56 detects that the cleaning holder 511 has reached one end of the movement path, and stops the travel of the linear member 54. As a result, the operation of the cleaning holder 511 and the cleaning holder 512 stops. Note that the execution of the cleaning mode will be described in detail later.

[0057] 10 is a block diagram showing an example of a control path used in the image forming apparatus 1. Note that, since various controls are performed on each section of the image forming apparatus 1 when the image forming apparatus 1 is used, the control path for the entire image forming apparatus 1 becomes complex. Therefore, the following description will focus on the parts of the control path that are necessary for implementing the present invention.

[0058] The voltage control circuit 71 is connected to a motor drive power supply 73, and operates the motor drive power supply 73 in response to an output signal from the control unit 90. The motor drive power supply 73 applies a predetermined drive voltage to the motor 55 in the optical scanning device 12 in response to a control signal from the voltage control circuit 71.

[0059] The operation unit 80 is provided with a liquid crystal display unit 81 and an LED 82 that indicates various states, and is configured to show the state of the image forming apparatus 1, the image formation status, and the number of copies to be printed. Various settings for the image forming apparatus 1 are made using the printer driver of the personal computer.

[0060] The control unit 90 includes at least a CPU (Central Processing Unit) 91 as a central processing unit, a ROM (Read Only Memory) 92 as a read-only memory unit, a RAM (Random Access Memory) 93 as a readable and writable memory unit, a timer 95, and an I / F (Interface) 96 that sends control signals to each device within the image forming apparatus 1 and receives input signals from the operation unit 70.

[0061] The ROM 92 stores data that will not be changed while the image forming apparatus 1 is in use, such as control programs for the image forming apparatus 1 and numerical values ​​necessary for control. The RAM 93 stores necessary data that is generated during the control of the image forming apparatus 1 and data that is temporarily necessary for the control of the image forming apparatus 1. The RAM 93 (or ROM 92) also stores the voltage value (DUTY) applied to the motor 55 in each operation mode of the cleaning holder 51, which will be described later, and the driving time of the motor 55, when cleaning the transparent member 52 of the optical scanning device 12. The timer 95 measures the driving time of the motor 55.

[0062] 11 is a flowchart showing an example of drive control of motor 55 in the cleaning mode. A first example of control of motor 55 will be described along the steps of FIG. 11, with reference to FIGS. 1 to 10 as needed.

[0063] When the cleaning mode starts, the control unit 90 determines whether the detection unit 56 is on (step S1). If the detection unit 56 is on (Yes in step S1), the cleaning holder 511 is placed in an initial position at one end of the movement path, and the light-shielding unit 511a is inserted between the light-emitting unit 56a and the light-receiving unit 56b to block the light emitted from the light-emitting unit 56a, as shown in Fig. 6. As a result, if the detection unit 56 is on in step S1, the control unit 90 determines that the cleaning holder 511 is in the initial position and proceeds to step S2.

[0064] On the other hand, if the detection unit 56 is off (No in step S1), the control unit 90 determines that the cleaning device holder 512 is positioned at one end of the movement path, and proceeds to step S8. In step S8, the return operation is started.

[0065] That is, when the cleaning mode starts, the control unit 90 uses the detection unit 56 to determine whether cleaning holder 511 or cleaning holder 512 is located at one end of the movement path, and then decides whether to start forward movement or backward movement. This allows the cleaning operation to start quickly regardless of whether cleaning holder 511 or cleaning holder 512 was located at one end of the movement path when the previous cleaning mode ended.

[0066] In step S2, the control unit 90 continues the forward rotation of the motor 55 in the first operation mode M1. The control unit 90 sends a control signal to the voltage control circuit 71 to supply a drive voltage from the motor drive power supply 73 to the motor 55. This causes the motor 55 to rotate forward in the first operation mode M1 (initial operation mode).

[0067] By the forward rotation of the motor 55, the linear member 54 moves in the direction of the arrow D1 from the state in FIG. 6, and the cleaning holder 511 starts to move downward in FIG. 6, and the cleaning holder 512 starts to move upward in FIG.

[0068] In step S3, the control unit 90 waits until the detection unit 56 is turned on. As the cleaning holder 511 moves downward in FIG. 6 from the initial position, the light-blocking portion 511a moves away from between the light-emitting portion 56a and the light-receiving portion 56b, and the detection unit 56 is turned off. If the detection unit 56 is turned off (No in step S3), the forward rotation of the motor 55 in the first operation mode M1 continues.

[0069] On the other hand, when the cleaning holder 512 approaches one end of the movement path (see FIG. 7), the tip of the light-shielding part 512a is inserted between the light-emitting part 56a and the light-receiving part 56b, and the detection part 56 is turned on. At this time, the process proceeds to step S4.

[0070] In step S4, the control unit 90 starts the forward rotation of the motor 55 in the second operation mode M2. The rotation speed of the motor 55 in the second operation mode M2 ​​is lower than the rotation speed of the motor 55 in the first operation mode M1. In step S4, the light-shielding unit 512a is further inserted between the light-emitting unit 56a and the light-receiving unit 56b. At this time, by making the rotation speed of the motor 55 in the second operation mode M2 ​​lower than the rotation speed of the motor 55 in the first operation mode M1, the detection unit 56 can accurately detect the movement of the light-shielding unit 512a.

[0071] In step S5, it is determined whether the detection unit 56 is in the ON state. By inserting the light-shielding portion 512a further between the light-emitting portion 56a and the light-receiving portion 56b, the through-hole 512b is inserted between the light-emitting portion 56a and the light-receiving portion 56b, and light emitted from the light-emitting portion 56a passes through the through-hole 512b. As a result, the light-receiving portion 56b receives the light from the light-emitting portion 56a, and the detection unit 56 is turned OFF. At this time, the control unit 90 determines that the cleaning holder 512 is positioned at one end of the movement path, and proceeds to step S7.

[0072] In step S7, the control unit 90 sends a control signal to the voltage control circuit 71 to stop the forward rotation of the motor 55. The operations in steps S1 to S7 described above are the forward movement of the cleaning holder 511 and the cleaning holder 512.

[0073] On the other hand, if the detection unit 56 is in the ON state in step S5, the process proceeds to step S6, where it is determined whether time T1 has elapsed. If time T1 has not elapsed, steps S5 and S6 are repeated to continue driving the motor 55 in the second operation mode M2 ​​until time T1 has elapsed. At this time, the light-shielding unit 512a is further inserted between the light-emitting unit 56a and the light-receiving unit 56b.

[0074] If the detection unit 56 remains on after the time T1 has elapsed, the control unit 90 determines that an error has occurred in the movement of the cleaning holder 511 or the cleaning holder 512, and proceeds to step S13. In step S13, the driving of the motor 55 is stopped and the cleaning mode is ended. At this time, an error is displayed on the LCD display unit 81.

[0075] Next, the control unit 90 sends a control signal to the voltage control circuit 71 to supply a drive voltage from the motor drive power supply 73 to the motor 55. This causes the motor 55 to rotate in reverse in the first operation mode M1 (step S8).

[0076] By the reverse rotation of the motor 55, the linear member 54 moves in the direction of the arrow D2 from the state in FIG. 7, and the cleaning holder 511 starts to move upward in FIG. 7, and the cleaning holder 512 starts to move downward in FIG.

[0077] In step S9, the control unit 90 waits until the detection unit 56 is turned on. As the cleaning holder 512 moves downward in FIG. 7, the light-blocking portion 512a moves away from between the light-emitting portion 56a and the light-receiving portion 56b, and the detection unit 56 remains in the off state. If the detection unit 56 is in the off state (No in step S9), the reverse rotation of the motor 55 in the first operation mode M1 continues.

[0078] On the other hand, when the cleaning holder 511 approaches one end of the movement path (see FIG. 6), the tip of the light-shielding part 511a is inserted between the light-emitting part 56a and the light-receiving part 56b, and the detection part 56 is turned on. At this time, the process proceeds to step S10.

[0079] In step S10, the control unit 90 starts reverse rotation of the motor 55 in the second operation mode M2. The rotation speed of the motor 55 in the second operation mode M2 ​​is lower than the rotation speed of the motor 55 in the first operation mode M1. At this time, by making the rotation speed of the motor 55 in the second operation mode M2 ​​lower than the rotation speed of the motor 55 in the first operation mode M1, the detection unit 56 can accurately detect the movement of the light-blocking portion 511a.

[0080] In step S11, it is determined whether or not the detection unit 56 is in the ON state. Even if the light-shielding unit 511a is further inserted between the light-emitting unit 56a and the light-receiving unit 56b, the through-hole 512b is not yet formed in the light-shielding unit 511a, and the detection unit 56 remains in the ON state.

[0081] In step S11, if the detection unit 56 is in the ON state, the process proceeds to step S12 to determine whether time T1 has elapsed. If time T1 has not elapsed, steps S11 and S12 are repeated to continue driving the motor 55 in the second operation mode M2 ​​until time T1 has elapsed.

[0082] If the detection unit 56 is still on after the time T1 has elapsed, the control unit 90 determines that the cleaning holder 511 has reached one end of the movement path, and proceeds to step S13. In step S13, the driving of the motor 55 is stopped, and the cleaning mode is ended.

[0083] On the other hand, if the detection unit 56 turns off before the time T1 has elapsed, it is determined that an error has occurred in the movement of either the cleaning holder 511 or the cleaning holder 512, and the process proceeds to step S13. In step S13, the driving of the motor 55 is stopped and the cleaning mode is ended. At this time, an error is displayed on the LCD display unit 81.

[0084] The above operations in steps S8 to S13 are the return operation by cleaning unit holder 511 and cleaning unit holder 512.

[0085] According to this embodiment, when the detection unit 56 detects that one of the cleaning holders 512 has reached one end of the movement path during execution of the cleaning mode, the outgoing movement is started (steps S1 and S2), and when the detection unit 56 detects that the other of the cleaning holders 511 has reached one end of the movement path, the return movement is started (steps S3 to S8). As a result, the control unit 90 determines whether to switch between the return movement and the outgoing movement based on the detection result of the detection unit 56, thereby reducing the load on the linear member 54 and preventing damage to the tensioning pulley 57.

[0086] Furthermore, the light-shielding portion 511a and the light-shielding portion 512a have different shapes, and the light-shielding portion 512a has a through-hole 512b. This allows the detection unit 56 to detect whether the cleaning holder 511 or the cleaning holder 512 has reached one end of the movement path based on the light-receiving pattern received by the light-receiving portion 56b. Therefore, the detection unit 56 can be simplified, and the manufacturing cost of the optical scanning device 12 can be reduced.

[0087] Furthermore, by forming through holes 512b in the light-shielding portion 512a, it is possible to easily detect whether cleaning holder 511 or cleaning holder 512 has reached one end of the movement path based on the light-receiving pattern received by light-receiving portion 56b.

[0088] Furthermore, by setting the state in which the cleaning holder 511 is positioned at one end of the movement path as the initial position when the cleaning mode starts, the detection unit 56 can detect the cleaning holder 511 in the on state. This makes it possible to prevent the occurrence of an initial error in the cleaning process.

[0089] Furthermore, when the cleaning mode starts, the control unit 90 uses the detection unit 56 to determine whether cleaning holder 511 or cleaning holder 512 is located at one end of the movement path, and determines whether to start forward movement or backward movement. This allows the cleaning operation to start quickly regardless of whether cleaning holder 511 or cleaning holder 512 was located at one end of the movement path when the previous cleaning mode ended.

[0090] The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present invention. For example, in the above-described embodiment, a tandem color printer was used as the image forming apparatus 1, but the present invention is not limited to color printers and can be applied to electrophotographic color image forming apparatuses such as color copiers and facsimiles. [Industrial Applicability]

[0091] 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 using the present invention, it is possible to provide an optical scanning device and an image forming apparatus equipped with the same that can suppress stretching and breakage of a linear member caused by continuous application of load to the linear member when a cleaning holder that cleans a transparent member that transmits laser light is stopped.

Claims

1. An optical scanning device that forms an electrostatic latent image by irradiating an image carrier with laser light, a housing having a plurality of laser light emission openings formed therein corresponding to the image carrier, the laser light emission openings extending in the main scanning direction of the laser light; a transparent member that is transparent to the laser light, extends in the main scanning direction of the laser light, and seals an exit port of the laser light; a linear member stretched in a ring shape on the housing; a drive unit that causes the linear member to travel in a first direction and a second direction; a guide rail arranged in parallel with the light exit port and extending in the extending direction of the transparent member; a pair of cleaning holders fixed to the linear member and moving in opposite directions on adjacent transparent members along the guide rail when the linear member is circularly moved by the driving unit; a cleaning member fixed to the cleaning holder and configured to clean the permeable member by sliding relative to the permeable member as the cleaning holder moves; a detector disposed on one side of the transparent member in the extending direction, the detector detecting that the cleaning holder has reached one end of the moving path of the cleaning holder; a control unit that controls the driving of the drive unit; Equipped with The control unit an outgoing movement in which the linear member is moved in the first direction, so that the cleaning holder moves along the extending direction of the permeable member; a return movement in which, after the outward movement, the linear member is caused to travel in the second direction, thereby moving the cleaning holder in a direction opposite to the outward movement; and During execution of the cleaning mode, when the detection unit detects that one of the cleaning holders has reached one end of the movement path of the cleaning holder, the outgoing movement is started, and when the detection unit detects that the other of the cleaning holders has reached one end of the movement path of the cleaning holder, the return movement is started, the detection unit includes a light-emitting unit that emits light in a parallel direction of the transparent members, and a light-receiving unit that receives the light emitted from the light-emitting unit; the pair of cleaning holders each have a light-blocking portion that is inserted between the light-emitting portion and the light-receiving portion when the cleaning holder reaches one end of the movement path and blocks the light emitted from the light-emitting portion; The light-shielding portions of the cleaning holders have different shapes, the other of the pair of cleaning holders has a through hole that penetrates the light-shielding portion and through which the light emitted from the light-emitting portion passes; When the other cleaning holder reaches one end of the movement path during execution of the cleaning mode, the detection unit detects that light emitted from the light emitting unit passes through the through hole and is received by the light receiving unit, An optical scanning device, characterized in that when one of the cleaning holders reaches one end of the movement path, the detection unit detects that the light emitted from the light emitting unit is blocked by the light blocking unit.

2. 2. The optical scanning device according to claim 1, wherein one of the cleaning holders is disposed at one end of the movement path of the cleaning holder when the cleaning mode is started.

3. The optical scanning device of claim 1, characterized in that when the cleaning mode starts, the control unit uses a detection unit to determine whether one or the other of the cleaning holders is positioned at one end of the cleaning holder's movement path, and decides whether to start the forward operation or the return operation.

4. one or more of the image carriers; an optical scanning device according to claim 1 , wherein an electrostatic latent image is formed on the image carrier by irradiating the image carrier with a laser beam; An image forming apparatus comprising:

Images