JP6266066B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus including an optical scanning device having a transparent window for passing laser light and a mechanism for moving a shutter that covers the transparent window for passing laser light.

  An optical scanning device provided in an electrophotographic image forming apparatus includes a transparent window that allows laser light deflected by a polygon mirror to pass outside the optical scanning device. Dust adhering to the transparent window blocks the laser beam, leading to a reduction in the quality of the output image. In particular, in the case of an optical scanning device that exposes a photosensitive member from the lower side in the direction of gravity, toner dropped from the developing device adheres to the transparent window due to vibration when removing a cartridge in which the developing device and the photosensitive member are integrated.

  For such a problem, Patent Document 1 describes an image forming apparatus in which a slit for passing a laser beam provided in an optical scanning device is moved by a shutter moving mechanism so as to prevent dust from being formed in the slit. . In FIG. 8 of Patent Document 1, a shutter is moved in a first direction by a motor, an opening is provided in the shutter, and an elastic force of a spring connected to the inner wall of the shutter opening and the upper cover of the optical scanning device is used. A configuration in which the shutter is moved in the second direction is described.

JP 2007-148276 A

  However, Patent Document 1 is configured to attach a spring to the upper cover of the optical scanning device. In the configuration of Patent Document 1, it is necessary to provide a gap for providing a spring between the shutter and the upper cover, or it is necessary to design the spring so that the spring fits inside the opening by increasing the thickness of the shutter. There arises a problem that the configuration of the shutter and the optical scanning device is increased.

In response to the above problems, the image forming apparatus of the present invention has a first light source that emits a first light beam for exposing the first photoconductor, and a second light source for exposing the second photoconductor. A second light source that emits the light beam, and the first light beam scans the first photoconductor, and the second light beam scans the second photoconductor. A rotating polygon mirror that deflects the first light beam and the second light beam on opposite sides of the rotating polygon mirror. A mirror, an optical box that accommodates the rotary polygon mirror therein, a cover that closes the optical box, and a first transparent window through which the first light beam deflected by the rotary polygon mirror passes. A second transparent that allows the second light beam deflected by the rotary polygon mirror to pass therethrough. And a cover disposed on opposite sides of the rotary polygon mirror, a cover disposed to face the cover, a position covering the first transparent window and the second transparent window, and the first A shutter that slides back and forth between an optical path of the first light beam that has passed through the transparent window and a position retracted from the optical path of the second light beam that has passed through the second transparent window; A pressing unit that slides the shutter by pressing the shutter, a direction that is connected to the shutter and the cover, and that the pressing unit presses as the amount of movement of the shutter pressed by the pressing unit increases; A spring that deforms so as to increase an elastic force that urges the shutter in the opposite direction, and slides the shutter in the opposite direction by the elastic force. And an opposite surface of the cover that faces the shutter is opposite to the first light source and the second light source with the rotary polygon mirror interposed therebetween, and the first A concave portion is provided between the transparent window and the second transparent window, the concave portion falling on the inner side of the optical box closed by the cover, and a coupling portion to which the spring coupled to the shutter is coupled to the concave portion. Provided,
In the rotation axis direction of the rotary polygon mirror, the base of the connecting portion standing from the bottom of the recess is located on the bottom side of the optical box with respect to the first transparent window. The image forming apparatus of the present invention also includes a first light source that emits a first light beam for exposing the first photoconductor, and a second light beam for exposing the second photoconductor. The first light beam and the second light source to be emitted and the first light beam scan the first photoconductor, and the second light beam scans the second photoconductor. A rotary polygon mirror that deflects the second light beam; an optical box that houses the rotary polygon mirror; and a cover that closes the optical box, the first polygon being deflected by the rotary polygon mirror A cover having a first transparent window through which a light beam passes and a second transparent window through which the second light beam deflected by the rotary polygon mirror passes; and a cover arranged to face the cover. , A position covering the first transparent window and the second transparent window, and the first A shutter that slides back and forth between an optical path of the first light beam that has passed through the transparent window and a position retracted from the optical path of the second light beam that has passed through the second transparent window; A pressing unit that slides the shutter by pressing the shutter, a direction that is connected to the shutter and the cover, and that the pressing unit presses as the amount of movement of the shutter pressed by the pressing unit increases; A shutter moving mechanism that includes a spring that is deformed so as to increase an elastic force that urges the shutter in the opposite direction and slides the shutter in the opposite direction by the elastic force, and is opposed to the shutter. A concave portion that falls into the inner side of the optical box is provided on the facing surface of the cover, and the concave portion is connected to the shutter. A connecting portion to which a connection is made, and when the optical box and the shutter moving mechanism are viewed from the rotational axis direction of the rotary polygon mirror, the concave portion, the first light source, and the second light source, The rotary polygon mirror is positioned between the two.

  According to the image forming apparatus of the present invention, the concave portion is provided on the facing surface of the cover that faces the shutter, and the spring for sliding the shutter is connected to the connecting portion provided in the concave portion, thereby configuring the shutter and the optical scanning device. Increase in size can be suppressed.

Schematic sectional view of the image forming apparatus Perspective view of appearance of image forming apparatus The figure which shows the connection state of a collection | recovery toner container and a cleaning apparatus, and the perspective view of the collection | recovery toner container 114 The figure which shows the state in which the collection | recovery toner container was attached to the image forming apparatus, and the enlarged view around a toner container holding mechanism Diagram showing process cartridge installation / removal configuration The perspective view which shows the structure of an optical scanning device, and sectional drawing of an optical scanning device Perspective view showing optical box and shutter Top view of shutter moving mechanism, shutter, and optical scanning device provided in main body of image forming apparatus Diagram showing shutter moving mechanism The figure which shows operation | movement of a shutter moving mechanism (shutter opening / closing mechanism). The figure which shows operation | movement of a shutter moving mechanism (shutter opening / closing mechanism). The figure which shows the effect by the shutter movement mechanism of Example 1.

Example 1
(Image forming device)
FIG. 1 is a schematic cross-sectional view of an electrophotographic image forming apparatus 100. An image forming apparatus 100 illustrated in FIG. 1 includes four image forming units 101Y, 101M, 101C, and 101BK that form toner images of yellow, magenta, cyan, and black. Each of the image forming units 101Y, 101M, 101C, and 101BK includes photosensitive drums 102Y, 102M, 102C, and 102BK that are photosensitive members. Each image forming unit includes charging devices 103Y, 103M, 103C, and 103BK that charge the photosensitive drums 102Y, 102M, 102C, and 102BK, and developing devices 104Y and 104M that develop the electrostatic latent image on the photosensitive drum using toner. , 104C, 104BK. Further, each image forming unit includes cleaning devices 111Y, 111M, 111C, and 111BK that remove residual toner on the photosensitive drum from the photosensitive drum.

  Each image forming unit constitutes a process cartridge in which the above-described photosensitive drum, charging device, developing device, and cleaning device are integrated. The process cartridge is an exchange unit that can be attached to and detached from the image forming apparatus. Hereinafter, the image forming units 101Y, 101M, 101C, and 101BK are referred to as process cartridges 101Y, 101M, 101C, and 101BK.

  The main body of the image forming apparatus 100 includes an optical scanning device 200, transfer rollers 105Y, 105M, 105C, and 105BK, an intermediate transfer belt 106, a cleaning device 112, a paper feeding unit 109, a paper discharge unit 110, a transfer roller 107, and a fixing device 108. Is provided. The optical scanning device 200 is disposed on the lower side in the gravity direction with respect to each photosensitive drum. The optical scanning device may be arranged to expose the photosensitive drum from the upper side in the gravity direction.

  Next, the image forming process will be described. The optical scanning device 200 emits light beams LY, LM, LC, and LBK (laser light) that expose the photosensitive drums 102Y, 102M, 102C, and 102BK charged by the charging devices 103Y, 103M, 103C, and 103BK, respectively. An electrostatic latent image is formed on the photosensitive drums 102Y, 102M, 102C, and 102BK by exposure with the light beam.

  The developing device 104Y develops the electrostatic latent image formed on the photosensitive drum 102Y with yellow toner. The developing device 104M develops the electrostatic latent image formed on the photosensitive drum 102M with magenta toner. The developing device 104C develops the electrostatic latent image formed on the photosensitive drum 102C with cyan toner. The developing device 104BK develops the electrostatic latent image formed on the photosensitive drum 102BK with black toner.

  The yellow toner image formed on the photosensitive drum 102Y is transferred to the intermediate transfer belt 106, which is an intermediate transfer body, by the transfer roller 105Y in the transfer portion Ty. The cleaning device 111Y collects toner remaining on the photosensitive drum 102Y without being transferred to the intermediate transfer belt 106, between the transfer portion Ty in the rotation direction of the photosensitive drum 102Y and the charging portion of the charging device 103Y.

  The magenta toner image formed on the photosensitive drum 102M is transferred to the intermediate transfer belt 106 by the transfer roller 105M at the transfer portion Tm. The cleaning device 111M collects the toner remaining on the photosensitive drum 102M without being transferred to the intermediate transfer belt 106 between the transfer portion Tm in the rotation direction of the photosensitive drum 102M and the charging portion of the charging device 103M.

  The cyan toner image formed on the photosensitive drum 102C is transferred to the intermediate transfer belt 106 by the transfer roller 105C at the transfer portion Tc. The cleaning device 111C collects the toner remaining on the photosensitive drum 102C without being transferred to the intermediate transfer belt 106 between the transfer portion Tc in the rotation direction of the photosensitive drum 102C and the charging portion of the charging device 103C.

  The black toner image formed on the photosensitive drum 102BK is transferred to the intermediate transfer belt 106 by the transfer roller 105BK at the transfer portion TBk. The cleaning device 111BK collects the toner remaining on the photosensitive drum 102BK without being transferred to the intermediate transfer belt 106 between the transfer portion TBk in the rotation direction of the photosensitive drum 102BK and the charging portion of the charging device 103BK.

  The cleaning devices 111Y, 111M, 111C, and 111BK of this embodiment include a blade that contacts the photosensitive drum, and collects the residual toner by scraping the toner remaining on the photosensitive drum by the blade.

  The toner images of the respective colors transferred onto the intermediate transfer belt 106 are transferred onto the recording paper conveyed from the paper supply unit 109 by the transfer roller 107 in the transfer unit T2. The toner image transferred to the recording paper in the transfer unit T2 is fixed by the fixing device 108 and discharged to the paper discharge unit 110 after the fixing process.

  The image forming apparatus 100 includes a cleaning device 112 between the transfer unit T2 and the transfer unit Ty in the rotation direction of the intermediate transfer belt 106. The cleaning device 112 includes a blade that comes into contact with the intermediate transfer belt 106, and scrapes residual toner on the intermediate transfer belt 106 with the blade, thereby removing toner remaining on the intermediate transfer belt 106 without being transferred to the recording medium. to clean up.

(Image forming device door and recovered toner container)
FIG. 2 is a perspective view of the appearance of the image forming apparatus 100. As shown in FIG. 2, the image forming apparatus 100 of this embodiment includes a maintenance door 113. A collected toner container 114 is attached to the inside of the door 113 of the image forming apparatus 100. The collected toner container 114 accumulates the toner collected from the respective photosensitive drums by the cleaning devices 111Y, 111M, 111C, and 111BK, and the toner collected from the intermediate transfer belt 106 by the cleaning device 112. The collected toner container 114 is an exchange unit that can be attached to and detached from the main body of the image forming apparatus 100. The user performs an operation of replacing the collected toner container 114 by displaying a prompt to replace the collected toner container 114 on a display unit (not shown).

  As shown in FIG. 2B, the user removes the collected toner container 114 from the image forming apparatus 100 by moving the collected toner container 114 attached to the image forming apparatus 100 in the −X direction (FIG. 2B). c)). On the other hand, when the user moves the collected toner container 114 in the + X direction from the state shown in FIG. 2C, the collected toner container 114 is attached to the image forming apparatus 100 as shown in FIG. It should be noted that the user cannot remove the process cartridge while the collected toner container 114 is attached to the image forming apparatus 100.

(Recovered toner container)
FIG. 3A is a diagram illustrating a connection state between the collected toner container 114 and the cleaning device 112. FIG. 3B is a perspective view of the collected toner container 114.

  As shown in FIG. 3B, a toner conveyance path 114 a connected to the cleaning device 112 is integrally formed in the collected toner container 114. The toner conveyance path 114a is provided with a toner receiving port 114d through which the toner conveyed from the cleaning device 112 flows. In a state where the collected toner container 114 is attached to the image forming apparatus, the toner receiving port 114d is connected to the toner conveyance path 112a of the cleaning device 112. The toner cleaned by the cleaning device 112 during image formation is moved by a transport screw (not shown) and passes through the toner transport path 112a on the cleaning device 112 side and the toner transport path 114a on the recovery toner container 114 side to the recovered toner container 114. Collected.

  Further, the collection toner container 114 is formed with receiving ports 114e, 114f, 114g, and 114h for receiving toner conveyed from the cleaning devices 111Y, 111M, 111C, and 111BK. The receiving port 114e is connected to the cleaning device 111Y, the receiving port 114f is connected to the cleaning device 111M, the receiving port 114g is connected to the cleaning device 111C, and the receiving port 114h is connected to the cleaning device 111BK.

  Further, the collected toner container 114 includes a toner accumulating portion 114i that accumulates toner flowing in from each cleaning device, and a protrusion 114b. As shown in FIG. 3B, the protrusion 114b includes a first flat surface 114b1 (first inclined portion) and a second flat surface 114b2 (second inclined portion). The first plane 114b1 is a plane inclined with respect to a virtual plane (XZ plane) parallel to the moving direction (X-axis direction) of the collected toner container 114b when the collected toner container 114 is attached and detached. On the other hand, the second plane 114b2 is a plane that is continuous with the first plane 114b1 and is inclined with respect to the virtual plane. The inclination angle of the second plane 114b2 with respect to the virtual plane is smaller than the inclination angle of the first plane 114b1 with respect to the virtual plane. In the present embodiment, the angle between the virtual plane and the second plane 114b2 is approximately 0 degrees. The protrusion 114b will be described later. The first plane 114b1 and the second plane 114b2 may have a linear shape such as a V-shaped top.

  FIG. 4A (a) is a diagram illustrating a state where the collected toner container 114 is attached to the image forming apparatus 100. The image forming apparatus 100 includes a toner container holding mechanism 115 (toner container holding unit) that holds the collected toner container 114 to such an extent that the user can easily attach and detach it. The toner container holding mechanism 115 includes a contact member 401 that contacts a protrusion 114 c (positioning protrusion) provided on the collected toner container 114 and a spring 402 that is attached to the contact member 401.

  4B to 4D are enlarged views around the toner container holding mechanism 115, and are diagrams for explaining an operation example of the toner container holding mechanism 115 when the collected toner container 114 is attached to and detached from the image forming apparatus. It is. FIG. 4B (b) shows a state before the collected toner container 114 is attached to a position (predetermined position) for receiving toner from each cleaning device. FIG. 4B (d) shows a state where the collected toner container 100 is attached to a predetermined position of the image forming apparatus. FIG. 4B (c) shows a state between FIG. 4A (a) and FIG. 4B (d).

  As shown in FIG. 4B (b), the contact member 401 includes a top 401a, an inclined surface 401b inclined to the door 113 side with the top 401a as a boundary, and an inclined surface 401c inclined to the side where the optical scanning device 200 is disposed. Is formed. The spring 402 is attached to the other end side of the contact member 401 when the top portion 401a is one end.

  When the user moves the collected toner container 114 in the + X direction of FIG. 4B (b) to attach the collected toner container 114 to the image forming apparatus, the collected toner container 114 is provided in the collected toner container 114 as shown in FIG. 4B (c). The positioning protrusion 114c comes into contact with the inclined surface 401b. When the user further moves the collected toner container 114 in the + X direction, the inclined surface 401b is pressed against the positioning protrusion 114c. Then, the spring 402 contracts, and the contact member 401 pressed by the positioning protrusion 114c moves in the −Z direction. When the user further moves the collected toner container 114 in the + X direction, the lower end of the positioning projection 114c and the top portion 401a come into contact with each other.

  When the user further moves the collected toner container 114 in the + X direction from the state in which the lower end of the positioning projection 114c is in contact with the top portion 401a, the positioning projection 114c comes into contact with the inclined surface 401c, and the contact member 401 is in FIG. It moves in the + Z direction shown in (d). When the collected toner container 114 moves to a predetermined position of the image forming apparatus, the positioning protrusion 114c is engaged with the contact member 401 as shown in FIG. 4B (d), and the collected toner container 114 is moved in the −X direction. The movement is restricted, and the collected toner container 114 is attached to a predetermined position of the image forming apparatus. In addition to the positions shown in FIGS. 4A and 4B, a plurality of toner container holding mechanisms 115 for positioning the collected toner container 114 with respect to the image forming apparatus are provided in the image forming apparatus. The collected toner container 114 is securely held at a predetermined position of the image forming apparatus by a plurality of toner container holding mechanisms.

(Removal of process cartridge)
As described above, the process cartridges 101Y, 101M, 101C, and 101BK are exchange units that can be attached to and detached from the image forming apparatus main body. As shown in FIG. 5B, the image forming apparatus 100 is provided with holding rails 501, 502, 503, 504, and 505 (cartridge holding units) that hold process cartridges. The holding rails 501 and 502 hold the process cartridge 101Y. Further, the holding rails 501 and 502 have a function of a guide rail (guide member) for guiding the movement of the process cartridge in the + X direction or the −X direction when the process cartridge 101Y is attached or detached. The holding rail 502 and the holding rail 503 hold the process cartridge 101M, the holding rail 503 and the holding rail 504 hold the process cartridge 101C, and the holding rail 504 and the holding rail 505 hold the process cartridge 101BK. Since the functions of the holding rail 503 to the holding rail 505 are the same as those of the holding rail 501 and the holding rail 502, the description thereof is omitted.

  When the collected toner container 114 is attached to the image forming apparatus, the collected toner container 114 covers a part of the process cartridge. Therefore, the process cartridge cannot be removed from the image forming apparatus in this state.

  Therefore, when replacing the process cartridge, the user opens the door 113 and then removes the collected toner container 114 from the image forming apparatus 100. When the collected toner container 114 is removed from the image forming apparatus, the process cartridges 101Y, 101M, 101C, and 101BK are slid in the −X direction as shown in FIG. Then, the user slides the process cartridge to be replaced in the −X direction, and removes the used process cartridge from the main body of the image forming apparatus 100. Thereafter, the user slides a new process cartridge in the + X direction and attaches the process cartridge to the main body of the image forming apparatus 100. Finally, the user attaches the collected toner container 114 to the image forming apparatus 100 and closes the door 113. When the user performs the above steps, the replacement of the process cartridge is completed.

(Optical scanning device)
Next, the optical scanning device 200 will be described. 6A is a perspective view showing the configuration of the optical scanning device 200, and FIG. 6B is a cross-sectional view of the optical scanning device 200. FIG.

  As shown in FIG. 6A, light source units 202Y, 202M, 202C, and 202BK are attached to the outer wall (side wall) of the optical box (housing) 201 of the optical scanning device 200. The light source unit 202Y that is a third light source emits a laser beam LY (third light beam) that exposes the photosensitive drum 102Y that is a third photosensitive member. The light source unit 202M that is a first light source emits a laser beam LM (first light beam) that exposes the photosensitive drum 102M that is a first photosensitive member. The light source unit 202C as the second light source emits a laser beam LC (second light beam) for exposing the photosensitive drum 102C as the second photosensitive member. The light source unit 202BK as the fourth light source emits laser light LBK (third light beam) for exposing the photosensitive drum 102BK as the fourth photosensitive member.

  The light source units 202Y, 202M, 202C, 202BK are arranged close to each other. Here, a plane crossing the polygon mirror 203 with the rotation axis of the polygon mirror 203 as a normal is defined as a virtual plane. The laser light LY emitted from the light source unit 202Y and the laser light LBK emitted from the light source unit 202Bk are incident on the reflecting surface of the polygon mirror 203 through an optical path obliquely incident on the virtual plane from the upper side in the gravity direction. On the other hand, the laser beam LC emitted from the light source unit 202C and the laser beam LM emitted from the light source unit 202M take an optical path obliquely incident on the virtual plane from the lower side in the gravitational direction and are reflected from the polygon mirror 203. Is incident on.

  As shown in FIG. 6A, a polygon mirror (rotating polygonal mirror) 203 having four reflecting surfaces is installed at the center of the optical box 201. During image formation, the polygon mirror 203 rotates the rotation axis indicated by the dotted line in FIG. 6A in the R1 direction.

  The laser beam LY emitted from the light source unit 202Y enters the reflection surface of the polygon mirror 203. The laser beam LY is deflected (reflected) to the A side shown in FIG. The laser beam LM emitted from the light source unit 202M is incident on the same reflecting surface as the reflecting surface of the polygon mirror 203 on which the laser beam LY is incident. The laser beam LM is deflected to the same side (A side) as the laser beam LY by the reflection surface of the polygon mirror 203.

  On the other hand, the laser beam LBK emitted from the light source unit 202BK is incident on a reflection surface different from the reflection surface on which the laser beams LY and LM are incident. The laser beam LBK is deflected by the reflection surface of the polygon mirror 203 to the B side shown in FIG. The laser beam LC emitted from the light source unit 202C is incident on the same reflecting surface as the reflecting surface of the polygon mirror 203 on which the laser beam LBK is incident. The laser beam LC is deflected to the same side (B side) as the laser beam LBK by the reflection surface of the polygon mirror 203.

  That is, the laser beam LY and the laser beam LBK are deflected by the polygon mirror 203 to the opposite sides with the polygon mirror 203 interposed therebetween. The laser beam LM and the laser beam LC are deflected by the polygon mirror 203 to the opposite sides with the polygon mirror 203 interposed therebetween.

  The laser beams LY and LM deflected by the polygon mirror 203 become laser beams that move in the + X direction. That is, by being deflected by the rotating polygon mirror 203, the laser beam LY becomes a laser beam that scans the photosensitive drum 102Y in the + X direction, and the laser beam LM becomes a laser beam that scans the photosensitive drum 102M in the + X direction.

  On the other hand, the laser beams LBK and LC deflected by the polygon mirror 203 become laser beams moving in the −X direction. That is, by being deflected by the rotating polygon mirror 203, the laser beam LBK becomes a laser beam that scans the photosensitive drum 102BK in the -X direction, and the laser beam LC becomes a laser beam that scans the photosensitive drum 102C in the -X direction. .

  Next, the optical paths of the laser beams LY, LM, LC, and LBK deflected by the polygon mirror 203 will be described with reference to FIG. As shown in FIG. 6B, the optical box 201 includes a polygon mirror 203, lenses 206, 207, 208, 209, 210, 211, reflection mirrors 212, 213, 214, 215, 216, 217, and the like. Optical components are attached. The optical box 201 is further provided with a cover 218 for dust-proofing the polygon mirror 203, each lens, and each reflection mirror.

  The laser beam LY deflected by the polygon mirror 203 passes through the lens 206 and the lens 207 and then enters the reflection mirror 212. The reflection mirror 212 reflects the incident laser beam LY toward the photosensitive drum 102Y. The cover 218 has an opening 219 through which the laser light LY reflected by the reflection mirror 212 passes. The opening 219 is closed by a transparent dustproof window 223 (third transparent window) that allows the laser beam LY to pass therethrough. The laser beam LY that has passed through the dustproof window 223 forms an image on the photosensitive drum 102Y.

  The laser beam LM deflected by the polygon mirror 203 passes through the lens 206 and then enters the reflection mirror 213. The reflection mirror 213 reflects the incident laser beam LM toward the reflection mirror 214 toward the lens 208. The laser beam LM reflected by the reflection mirror 213 passes through the lens 208 and enters the reflection mirror 214. The reflection mirror 214 reflects the incident laser light LM toward the photosensitive drum 102M. The cover 218 has an opening 220 through which the laser light LM reflected by the reflection mirror 214 passes. The opening 219 is closed by a transparent dustproof window 224 (first transparent window) that allows the laser light LM to pass therethrough. The laser beam LM that has passed through the dustproof window 224 forms an image on the photosensitive drum 102M.

  The laser beam LBK deflected by the polygon mirror 203 passes through the lens 209 and the lens 210 and then enters the reflection mirror 215. The reflection mirror 215 reflects the incident laser beam LBK toward the photosensitive drum 102BK. The cover 218 has an opening 222 through which the laser light LBK reflected by the reflection mirror 215 passes. The opening 222 is closed by a transparent dustproof window 226 (fourth transparent window) that allows the laser beam LBK to pass therethrough. The laser beam LBK that has passed through the dustproof window 222 forms an image on the photosensitive drum 102BK.

  The laser beam LC deflected by the polygon mirror 203 passes through the lens 209 and then enters the reflection mirror 216. The reflection mirror 216 reflects the incident laser light LC toward the lens 211. The laser beam LC reflected by the reflection mirror 211 passes through the lens 211 and enters the reflection mirror 217. The reflection mirror 217 reflects the incident laser beam LC toward the photosensitive drum 102C. The cover 218 has an opening 221 through which the laser light LC reflected by the reflection mirror 218 passes. The opening 221 is closed by a transparent dustproof window 225 (second transparent window) that allows the laser light LC to pass therethrough. The laser beam LC that has passed through the dustproof window 225 forms an image on the photosensitive drum 102C.

(cover)
The cover 218 will be described. As shown in FIG. 7A, a cover 218 is attached to the optical box 201 in order to close the internal space of the optical box 201. The cover 218 is provided with a plurality of hook portions 218a. The cover 218 is attached to the optical box 201 by a snap-fit structure in which the plurality of hook portions 218a are engaged with the plurality of protrusions 220a provided on the outer wall of the optical box. It is done. As shown in FIG. 7A, the cover 218 includes a recess 218 b that falls toward the inside of the optical box 201 on the facing surface 218 g of the cover 218 that faces the shutter 300, and toward the outside of the optical box 201. Projecting convex portions 218c (first convex portions) and 218d (second convex portions) are provided.

(Shutter)
Next, the shutter 300 will be described. The shutter 300 is a member for preventing foreign matters such as toner from adhering to the dustproof windows 223, 224, 225, and 226. When the user opens the door 113 and attaches / detaches the process cartridge in order to perform maintenance of the image forming apparatus, the toner may fall from the cartridge due to the movement of the process cartridge. Therefore, at least when the process cartridge is replaced, it is desirable that the shutter 300 covers the dustproof windows 223, 224, 225, and 226.

  FIG. 7B is a perspective view showing the shutter 300 attached to the optical scanning device so as to cover the cover 218. The shutter 300 is a single plate-like resin member that faces the cover 218 and is a common member that covers the dustproof windows 223, 224, 225, and 226 of the cover 218. In this embodiment, the outer shape of the shutter 300 is a rectangle that is substantially the same as the outer shape of the cover 218 of the optical scanning device. The shutter 300 includes an opening 323 that allows the laser light LY that has passed through the dust-proof window 223 to pass, an opening 324 that allows the laser light LM that has passed through the dust-proof window 224 to pass, and an opening 325 that allows the laser light LC that has passed through the dust-proof window 225 to pass. An opening 326 (light beam passage portion) through which the laser light LBK that has passed through the dustproof window 226 passes is formed. The shutter 300 is formed with a long hole 301 for attaching a spring 310 which is an elastic body to be described later. In addition, elongated holes 302 and 303 are formed in the shutter 300. The convex part 218c of the cover 218 is inserted into the long hole 302 (first insertion part). On the other hand, the convex part 218d of the cover 218 is inserted into the elongated hole 303 (second insertion part). The long holes 302 and 303 and the convex portions 218c and 218d are engaging mechanisms in which the long hole 302 and the convex portion 218c and the long hole 303 and the convex portion 218d engage with each other, and the moving direction (sliding direction) of the cover 218 is changed. It functions as a guide mechanism that restricts in the Y-axis direction. Since the long hole 302 and the long plan 303 are long holes in a direction parallel to the Y axis of the shutter 300, the movement of the shutter 300 is performed in a reciprocating direction parallel to the Y axis by the long holes 302 and 303 and the convex portions 218c and 218d. Be regulated. The shutter 300 may be attached to the image forming apparatus side.

  Note that the convex portion provided on the shutter 300 side, the concave portion (insertion portion) corresponding to the long hole provided on the cover 218 side, and the convex portion provided on the shutter 300 side may be inserted into the concave portion to serve as a guide member.

(Shutter moving mechanism)
The shutter 300 according to the present embodiment is provided to prevent dust such as toner from adhering to the dustproof windows 223, 224, 225, and 226 of the cover 218. The shutter 300 moves when a mechanism for moving the shutter described below operates.

  FIG. 8A is a top view of the shutter moving mechanism, the shutter, and the optical scanning device provided in the image forming apparatus 100 main body. FIG. 8B is a top view of the rotation mechanism 400 constituting a part of the shutter moving mechanism.

  As illustrated in FIG. 8B, the rotation mechanism 803 includes a rotation shaft 804, a rotation unit 805, a first arm unit 806, and a second arm unit 807. The rotation shaft 804 is a fixed shaft provided in the main body of the image forming apparatus 100 and having a circular cross section. The rotation unit 805, the first arm unit 806, and the second arm unit 807 constitute one rotation member, and the shaft 804 passes through an opening 808 provided in the rotation unit 805. A first arm portion 806 and a second arm portion 807 extend from the rotating portion 805 in the radial direction of the shaft 804.

  As shown in FIG. 8A, the rotating member constituted by the rotating unit 805, the first arm unit 806, and the second arm unit 807 has a rotating shaft 804 as a center of rotation (having a circular cross section of the rotating shaft 804). It can rotate in the clockwise direction (first rotation direction) and the counterclockwise direction (second rotation direction: the direction opposite to the first rotation direction) with the center as the rotation center.

  Next, the spring 310 constituting a part of the shutter moving mechanism will be described with reference to FIG. Fig.9 (a) is sectional drawing between AA of Fig.8 (a). FIG. 9B is an enlarged perspective view of the recess 218 b provided in the cover 218. FIG. 9C shows an enlarged perspective view of the opening 301 of the shutter 300. FIG. 9D is an enlarged cross-sectional view of the attachment portion of the spring 310.

  As shown in FIG. 9B, the concave portion 218b of the cover 218 is provided with an engaging portion 218e (second connecting portion) with which one end of a spring 310 such as a coil spring engages. On the other hand, as shown in FIG. 9C, the shutter 300 is provided with an engaging portion 304 (first connecting portion) with which the other end of the spring 310 is engaged. That is, the cover 218 and the shutter 300 are connected by the spring 310.

  As shown in FIG. 9A, the bottom surface 218f of the recess 218b of the cover 218 is closer to the optical box 201 than the dustproof windows 223, 224, 225, 226 in the rotation axis direction (Z-axis direction) of the polygon mirror 203. It is provided on the bottom side.

  The recess 218b is provided on an extension of the optical path of the laser light that is emitted from the light source units 202Y, 202M, 202C, and 202BK and enters the polygon mirror 203. That is, when viewed from the rotation axis direction of the polygon mirror 203, the recess 218b is provided on the opposite side of the light sources 202Y, 202M, 202C, and 202BK with the polygon mirror 203 interposed therebetween. 8A indicates the arrangement position of the rotary polygon mirror, and line segments 801 and 802 indicate the scanning region end portions of the laser light deflected by the polygon mirror 203. In FIG. Here, the scanning area refers to an effective scanning area corresponding to one end to the other end of the electrostatic latent image formed on the photosensitive drum in the rotation axis direction of each photosensitive drum. As shown in FIG. 8A, when viewed from the rotational axis direction of the polygon mirror 203, the recess 218b of the cover 218 avoids the optical path of each laser beam deflected by the polygon mirror 203 inside the optical scanning device. In the position. Therefore, it is possible to provide a recess 218b that protrudes to the inside of the optical scanning device from the position of the dustproof window in the rotation axis direction of the polygon mirror 203 without interfering with the optical path of each laser beam inside the optical scanning device. . In addition, a connecting portion to which the spring 310 is connected is provided on the bottom surface 218f of the recess 218b so that the spring 310 can be received in the recess 218b.

  By providing the recess 218b on the facing surface 218g facing the shutter 300 of the cover 218 in this way, the spring 310 does not have to be provided on the facing surface 218g, and therefore the optical scanning device 200 in the rotation axis direction of the polygon mirror 203 can be provided. Larger size can be avoided. Further, since the shutter 300 and the cover 218 can be disposed close to each other, an increase in the size of the guide members such as the convex portions 218c and 218d can be suppressed.

(Operation of shutter moving mechanism)
Next, the operation of the shutter moving mechanism (shutter opening / closing mechanism) will be described with reference to FIGS.

  FIG. 10A is a top view of a state before the collected toner container 114 is mounted on the toner container holding mechanism 115. In FIG. 10A, the shutter 300 covers openings 223, 224, 225, and 226 provided in the cover 218. Even if the laser beams LY, LM, LC, and LBK are emitted, Laser light is blocked by the shutter. In this embodiment, the state shown in FIG. 10A is the shutter closed state where the shutter 300 shields the laser light, or the state where the shutter 300 is located at the second position located on the optical path of the laser light.

  FIG. 10B is a top view of the state in which the collected toner container 114 is held by the toner container holding mechanism 115. In FIG. 10B, the shutter 300 is located at the first position retracted from the optical path of the laser light. Therefore, the laser beams LY, LM, LC, and LBK can pass through the openings 223, 224, 225, and 226 of the shutter member 300. In this embodiment, the state shown in FIG. 10A is a shutter open state where the shutter 300 does not block the laser beam.

  In the state of FIG. 10A, the tip end portion 806a of the first arm portion 806 (first moving portion) and the protrusion 114b of the collected toner container 114 are in contact with each other, and the second arm portion 807 (second The front end 807a of the moving part) and the end of the shutter 300 are in contact with each other (the left figure in FIG. 10A). In addition, the right figure of Fig.10 (a) has shown the state of the spring 310 in the state of the left figure of Fig.10 (a).

  Fig.11 (a) is an enlarged view of the rotation mechanism 803 in the state of Fig.10 (a). The positions of the first arm portion 806 and the second arm portion 807 shown in FIG. In the subsequent FIGS. 11B to 11D, the initial positions of the first arm portion 806 and the second arm portion 807 are indicated by dotted lines. In this embodiment, movement of the shutter in the + Y direction is defined as movement in the first direction, and movement in the −Y direction is defined as movement in the second direction. The movement in the + Y direction of the shutter may be defined as the movement in the second direction, and the movement in the −Y direction may be defined as the movement in the first direction.

  When the user moves the collected toner container 114 in the + X direction from the state of FIG. 10A, the tip end portion 806a of the first arm portion 806 moves in the arrow C direction on the first flat surface 114b1 of the protrusion 114b. . When the tip end portion 806a of the first arm portion 806 moves in the direction of arrow C, the first arm portion 806 turns (moves) clockwise around the rotation shaft 804, and at the same time, the second arm portion 807 is moved. Also turns (moves) in the clockwise direction (FIG. 11B).

  The shutter 300 pressed by the distal end portion 807a of the second arm portion 807 that is turned (moved) by turning the first arm portion 806 slides in the −Y direction (short direction of the transparent window). When the shutter 300 slides in the −Y direction from the state of FIG. 11A, the spring 310 expands. The amount of movement of the shutter 300 in the −Y direction increases as the elastic force of the spring 310 (the biasing force that biases the shutter 300 in the + direction by the spring 310). The elastic force of the spring 310 acts on the shutter 300 in the + Y direction. Therefore, the state where the shutter 300 and the distal end portion 807a of the second arm portion 807 are in contact with each other is maintained.

  When the user further moves the collected toner container 114 in the + X direction from the state of FIG. 11B, the first arm 806 and the second arm 807 are rotated clockwise by the movement of the collected toner container 114 in the + X direction. Turn in the direction. Then, the shutter 300 pressed by the second arm portion 807 further slides in the −Y direction (FIG. 11C).

  In the state of FIG. 11C, the collected toner container 114 is not completely held by the toner container holding mechanism 115 of the image forming apparatus 100, and can be further moved in the + X direction. When the user further moves the collected toner container 114 in the + X direction from the state shown in FIG. 11C, the tip end portion 806a of the first arm portion 806 comes into contact with the second flat surface 114b2 of the protrusion 114b. The second plane 114b2 is a plane parallel to the X axis. Therefore, even if the front end portion 806a of the first arm portion 806 moves on the second plane 114b, the first arm portion 806 and the second arm portion 807 can move in either clockwise or counterclockwise directions. Do not turn.

  When the contact point between the first arm 806 and the second flat surface 114b2 of the protrusion 114b is at the position shown in FIG. 11D, the recovered toner container 114 is a toner container holding mechanism as shown in FIG. 4B (d). 115 is held. By setting the second plane 114b to be a plane parallel to the X axis, the tip 806a of the first arm 806 is in contact with the tip 806a of the first arm 806 and the second plane 114b2. A force in the −X direction does not act on the protrusion 114b. By providing the second flat surface 114b2 in this way, it is possible to suppress the recovered toner container 114 from being detached from the toner container holding mechanism 115 in the −X direction in the state of FIG. 4B (d) due to vibration or the like.

  As shown in FIGS. 10A and 10B, in the image forming apparatus of this embodiment, the contact between the second arm portion 807 and the shutter 300 regardless of the position of the shutter 300 in the Y-axis direction. Portion (first contact portion), engagement portion 304 as a contact portion (second contact portion) between shutter 300 and spring 310, and engagement portion 218e as a contact portion between spring 310 and cover 218 are substantially straight. Arranged above (on the dotted line in FIG. 10A). With this configuration, the direction in which the force is applied from the second arm 807 to the shutter 300 and the direction in which the force is applied from the spring 310 to the shutter 300 are substantially collinear (on the dotted line in FIG. 10A). On. Therefore, the generation of a rotational moment with respect to the shutter 300 due to the force acting on the shutter 300 from the second arm 807 and the spring 310 is suppressed. Therefore, it is possible to reduce the load on the engaging mechanism of the convex portion 218c inserted into the long hole 302 and the convex portion 218d inserted into the long hole 303 due to the rotation of the shutter 300. And since the load concerning the convex part 218c and the convex part 218d is reduced, the deformation | transformation of the optical scanning device containing the cover 218 can be suppressed, As a result, the optical path of the laser beam resulting from a deformation | transformation of an optical scanning device A decrease in image quality due to fluctuations can be suppressed.

  In the image forming apparatus according to the present exemplary embodiment, the convex portion 218c inserted into the elongated hole 302 and the convex portion 218d inserted into the elongated hole 303 are arranged on the dotted line in FIG. With such a configuration, the pressing force pressing the shutter 300 in the −Y direction by the second arm portion 807 is applied to the convex portion 218c and the convex portion 218d from the long hole 302 and the long hole 303 of the shutter 300, respectively. Conversion to force acting in the X-axis direction can be suppressed. In addition, the elastic force of the spring 310 that biases the shutter 300 in the −Y direction is converted into a force acting in the X-axis direction on the convex portion 218c and the convex portion 218d from the long hole 302 and the long hole 303 of the shutter 300, respectively. Can be suppressed. That is, when the shutter 300 is moved, generation of a force acting in the X-axis direction on the convex portions 218c and 218d can be suppressed, so that deformation of the optical scanning device 200 (particularly, the cover 218) is suppressed. can do.

  Note that, in the X-axis direction, the position of the contact portion between the second arm portion 807 and the shutter 300 is slightly changed by the rotational movement of the second arm portion 807. Therefore, in the image forming apparatus of the present embodiment, the movement range of the contact portion between the second arm portion 807 and the shutter 300 accompanying the movement of the second arm portion 807 is within the width of both ends of the long hole in the X-axis direction. Designed to fit. In the present embodiment, as long as the movement range of the contact portion between the second arm portion 807 and the shutter 300 is within the width of both ends of the long hole in the X-axis direction, the contact portion between the second arm portion 807 and the shutter 300 is It is defined that an engagement portion 218e that is a contact portion between the shutter 300 and the spring 310 and an engagement portion 218e that is a contact portion between the spring 310 and the cover 218 are substantially on a straight line.

  In the present embodiment, the convex portion 218d is provided between the dustproof window 223 and the dustproof window 224 of the cover 218, and the convex portion 218c is provided between the dustproof window 225 and the dustproof window 226. Further, a long hole 303 is provided between the opening 323 and the opening 324 of the shutter 300, a long hole 302 is provided between the opening 325 and the opening 326, and an opening 301 is provided between the opening 324 and the opening 325. Yes. With this configuration, the contact portion between the second arm portion 807 and the shutter 300 and the contact portion between the shutter 300 and the spring 310 regardless of the position of the shutter 300 in the Y-axis direction. The engaging portion 218e which is a contact portion between the joining portion 304 spring 310 and the cover 218, the convex portion 218c inserted into the elongated hole 302, and the convex portion 218d inserted into the elongated hole 303 can be arranged on a substantially straight line. .

  FIG. 12 is a diagram illustrating the magnitude of the force in the −X direction that acts on the collected toner container 114 from the first arm portion 806. (A) to (d) shown on the horizontal axis in FIG. 12 correspond to FIGS. 11 (a) to (d), respectively. In the state of FIG. 11A, the force of Fa acts in the + Y direction from the shutter 113 to the second arm portion 807 by the elastic force of the spring 310 that biases the shutter 300 due to the extension of the spring 310. Thus, the force of F′a corresponding to Fa acts on the first plane 114b1 from the first contact portion 806a of the first arm portion 806. If the angle between the direction in which F′a acts at this time and the X-axis direction is θb, the collected toner container 114 in the state of FIG. 11A has a force of F′a × cos θa in the −X direction. Works. In the configuration of this embodiment, a force of about 130 gf acts on the collected toner container 114 in the −X direction in the state shown in FIG.

  When the user moves the collected toner container 114 in the + X direction from the state shown in FIG. 11A, the elastic force of the spring 310 that urges the shutter 300 due to the extension of the spring increases. Forces Fb (FIG. 11 (b)) and Fc (FIG. 11 (c)) larger than Fa act on the arm (Fa <Fb <Fc). Therefore, F′b corresponding to Fb and F′c corresponding to Fc act on the first plane 114b1 from the first contact portion 806a of the first arm portion 806. In the state shown in FIG. 11B, F′b × cos θb acts in the −X direction in the state shown in FIG. 11B, and F′c × cos θc acts in the −X direction in the state shown in FIG. In the configuration of this embodiment, about 200 gf of force in the −X direction acts on the collected toner container 114 in the state of FIG. 11B, and about 210 gf of force in the −X direction in the state of FIG. Act.

  On the other hand, in the state of FIG. 11D, the second plane 114b2 and the contact portion 806a of the first arm portion 806 are in contact with each other, and therefore the force acting on the collected toner container 114 in the −X direction is 0 gf. Become. Therefore, in FIG. 11D, the collected toner container 114 is in a state where it is difficult to drop off from the toner container holding mechanism 115. Note that the second plane 114b2 does not necessarily have to be parallel to the X axis, and it is desirable to make the inclination angle of the second plane 114b2 smaller than the inclination angle of the first plane 114b1 with respect to the X axis. Further, the contact portion 806a does not need to be configured by only two planes such as the first plane 114b1 and the second plane 114b2, and may be configured by three or more planes. Further, the shape of the contact portion 806a may be a curved surface in which the inclination angle with respect to the virtual plane becomes gentler in the −X direction.

  As described above, the concave portion 218b is provided on the facing surface 218g of the cover 218 facing the shutter 300, and the spring 310 for sliding the shutter 300 is connected to the connecting portion 218e provided on the concave portion 218b. And the enlargement of the structure of an optical scanning device can be suppressed.

  The present invention is not limited to the above-described embodiment, and various changes and modifications can be made without departing from the spirit and scope of the present invention. Therefore, in order to make the scope of the present invention public, the following claims are attached.

218 Cover 218b Concave part 218c, 218d Convex part 218e Engaging part 218g Opposing surface 302, 303 Long hole 300 Shutter 310 Spring

Claims (5)

A first light source that emits a first light beam for exposing the first photoreceptor;
A second light source that emits a second light beam for exposing the second photoreceptor;
The first light beam and the second light beam are deflected so that the first light beam scans the first photoconductor and the second light beam scans the second photoconductor. A rotating polygon mirror that deflects the first light beam and the second light beam to opposite sides of the rotating polygon mirror; and
An optical box that houses the rotary polygon mirror;
A cover for closing the optical box, wherein the first transparent window through which the first light beam deflected by the rotary polygon mirror passes and the second light beam deflected by the rotary polygon mirror pass through. A second transparent window to be covered with a cover disposed on the opposite side of the rotary polygon mirror;
Positioned to face the cover, covers the first transparent window and the second transparent window, the optical path of the first light beam that has passed through the first transparent window, and the second A shutter that slides back and forth between a position retracted from the optical path of the second light beam that has passed through the transparent window;
A pressing unit that slides the shutter by pressing the shutter, a direction that is connected to the shutter and the cover, and that the pressing unit presses as the amount of movement of the shutter pressed by the pressing unit increases; A shutter moving mechanism that includes a spring that deforms so as to increase an elastic force that urges the shutter in the opposite direction and slides the shutter in the opposite direction by the elastic force,
The facing surface of the cover facing the shutter is on the opposite side of the first light source and the second light source with the rotary polygon mirror interposed therebetween, and the first transparent window and the second transparent A recess is provided between the window and the inner side of the optical box closed by the cover, and the recess is provided with a connecting portion to which the spring connected to the shutter is connected.
The image forming apparatus according to claim 1, wherein a base of the connecting portion standing from a bottom portion of the concave portion is positioned closer to a bottom portion side of the optical box than the first transparent window in a rotation axis direction of the rotary polygon mirror. A third light beam is emitted to expose a third photoconductor disposed on the same side of the rotary polygon mirror as the first photoconductor and further from the first photoconductor. A third light source;
A fourth light beam is emitted to expose a fourth photoconductor disposed on the same side of the rotary polygon mirror as the second photoconductor and far from the second photoconductor. A fourth light source,
The third light beam is deflected to the same side as the first light beam by the rotary polygon mirror so that the third light beam scans the third photoconductor,
The fourth light beam is deflected to the same side as the second light beam by the rotary polygon mirror so that the fourth light beam scans the fourth photoreceptor,
The cover is disposed at a position farther than the first transparent window with respect to the rotary polygon mirror, and a third transparent window through which the third light beam deflected by the rotary polygon mirror passes, A fourth transparent window disposed at a position farther than the second transparent window with respect to the rotary polygon mirror and allowing the fourth light beam deflected by the rotary polygon mirror to pass therethrough. The image forming apparatus according to claim 1 . The concave portion is provided at a position outside the scanning region of the first light beam and the second light beam deflected by the rotary polygon mirror when the optical box is viewed from the rotation axis direction of the rotary polygon mirror. The image forming apparatus according to claim 1 , wherein the image forming apparatus is provided. The concave portion includes the first light beam, the second light beam, and the third light beam that are deflected by the rotary polygon mirror when the optical box is viewed from a rotation axis direction of the rotary polygon mirror. The image forming apparatus according to claim 2 , wherein the image forming apparatus is provided at a position outside a scanning region of the fourth light beam. A first light source that emits a first light beam for exposing the first photoreceptor;
A second light source that emits a second light beam for exposing the second photoreceptor;
The first light beam and the second light beam are deflected so that the first light beam scans the first photoconductor and the second light beam scans the second photoconductor. Rotating polygon mirror,
An optical box that houses the rotary polygon mirror;
A cover for closing the optical box, the first transparent window through which the first light beam deflected by the rotary polygon mirror passes; and the second light beam deflected by the rotary polygon mirror. A cover having a second transparent window to pass through;
Positioned to face the cover, covers the first transparent window and the second transparent window, the optical path of the first light beam that has passed through the first transparent window, and the second A shutter that slides back and forth between a position retracted from the optical path of the second light beam that has passed through the transparent window;
A pressing unit that slides the shutter by pressing the shutter, a direction that is connected to the shutter and the cover, and that the pressing unit presses as the amount of movement of the shutter pressed by the pressing unit increases; A shutter moving mechanism that includes a spring that deforms so as to increase an elastic force that urges the shutter in the opposite direction and slides the shutter in the opposite direction by the elastic force,
A concave portion that falls into the inner side of the optical box is provided on the facing surface of the cover that faces the shutter, and a coupling portion to which the spring coupled to the shutter is coupled is provided in the concave portion,
When the optical box and the shutter moving mechanism are viewed from the rotation axis direction of the rotary polygon mirror, the rotary polygon mirror is positioned between the concave portion, the first light source, and the second light source. An image forming apparatus.