JP6188501B2 - Optical scanning apparatus and image forming apparatus - Google Patents

Description

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

  2. Description of the Related Art An electrophotographic image forming apparatus such as a laser beam printer or a digital copying machine is provided with an optical scanning device for exposing a photosensitive member. The optical scanning device deflects the laser light emitted from the semiconductor laser with a rotating polygon mirror and scans the photosensitive member. As a result, an electrostatic latent image is formed on the photosensitive member, and a toner image is formed by attaching the toner to the electrostatic latent image and developing it, and this is transferred to a sheet to create an image.

  In recent years, colorization of image forming apparatuses has progressed, and color image forming apparatuses include a so-called tandem method in which an image of each color is collectively formed on an intermediate transfer body with a dedicated photoconductor for each color. The so-called method is becoming mainstream. Further, in this tandem image forming apparatus, since it is advantageous in unit size and cost, a so-called 4-in-1 optical scanning apparatus that performs exposure of all four colors with one rotating polygon mirror is widely used. .

  By the way, recent trends in image forming apparatuses include higher speed and higher resolution in addition to the above-mentioned colorization. In order to realize this high speed and high resolution, the rotating polygon mirror may be rotated at high speed as one means. However, when the rotary polygon mirror is rotated at a high speed, a high negative pressure is generated inside the optical scanning device around the vicinity of the rotary polygon mirror, and air is easily sucked from the outside of the optical scanning device. In some cases, the air outside the optical scanning device is mixed with very fine dust and dirt and volatile substances such as grease used in the image forming apparatus itself. When such air enters the inside of the optical scanning device, the adhesion to the reflecting surface of the rotating polygon mirror proceeds in several weeks to several months, and the light intensity of the exposure decreases and the density becomes extremely thin partially. May cause defects.

  In order to prevent this, the cover of the optical box is provided with an elastic seal member made of synthetic rubber, polyurethane, or the like at the joint that contacts the outer peripheral edge of the optical box. By sealing the optical box, the inside of the optical box is secured. Up to now, this seal member has been attached to a cover or optical box with double-sided tape, but in order to seal it securely, it is necessary to apply it carefully along the shape of the cover member or optical box. The work was very complicated.

  On the other hand, in Patent Document 1, for example, an assembly process is performed by adopting a configuration in which an elastomer seal member is integrally injection-molded into an optical box or a cover instead of attaching a separate seal member. An optical scanning device having a hermeticity while being simplified is proposed.

JP 2004-262118 A

  As described above, when the sealing member is injection-molded on the cover of the optical box, a gate portion for filling the melted material forming the sealing portion is required. In this gate portion, the material injected at the time of molding is not contained. In some cases, it accumulates to form a convex gate mark.

  In recent years, in order to efficiently use the space inside the apparatus for the purpose of saving space, a so-called bottom exposure method in which an optical scanning device exposes from the lower surface of a photoreceptor is often used. In such a bottom exposure type image forming apparatus, when a process cartridge integrated with a photoreceptor or a developing device is attached or detached for maintenance and inspection, toner or the like may scatter from the process cartridge due to an impact at the time of attachment or detachment. is there. When these scattered objects fall and adhere to the exit window of the optical scanning device, the scanning light traveling toward the photosensitive member may be blocked, causing streak-like image defects. For this reason, in order to avoid the adhering of scattered objects, an open / close type dustproof shutter is often provided on the upper part of the bottom exposure type optical scanning device. In particular, since there is a restriction on the space between the photosensitive member and the optical scanning device, a shutter of a type that slides a flat shutter is often used.

  However, when such a slide type shutter is combined with the cover having the above-described injection-molded seal member, if there is a gate portion of the seal member on the side facing the shutter, the protruding gate mark is formed on the shutter. May interfere with the operation of the shutter.

  The present invention has been made under such circumstances, and it is an object of the present invention to ensure high dustproof performance of an optical scanning device and reliable operation of a shutter covering the upper portion thereof.

  In order to solve the above-described problems, the present invention is configured as follows.

  (1) A light source, a deflecting unit that deflects the light beam emitted from the light source, an optical member that guides the light beam deflected by the deflecting unit to a photosensitive member, the light source, and the deflecting unit, An optical box that houses an optical member; a transparent window that allows the light beam to pass through; a cover that covers an open surface of the optical box; and the transparent window that is disposed between the photoconductor and the cover. And a shutter that moves between a position retracted from the optical path of the light beam that has passed through and a position covering the transparent window, wherein the cover is in contact with the optical box. A light having a sealing member molded integrally with a cover, and a gate portion for molding the sealing member is provided in a concave portion provided on a surface of the cover facing the shutter. scanning Location.

  (2) A light source, a deflecting unit that deflects the light beam emitted from the light source, an optical member that guides the light beam deflected by the deflecting unit to a photosensitive member, the light source, and the deflecting unit, and An optical box that houses an optical member; a transparent window that allows the light beam to pass through; a cover that covers an open surface of the optical box; and the transparent window that is disposed between the photoconductor and the cover. And a shutter that moves between a position retracted from the optical path of the light beam that has passed through and a position that covers the transparent window, wherein the cover is disposed at a portion that contacts the optical box. One or more gate portions for molding a seal member molded integrally with the cover, and the shutter includes a recess at a position facing each of the gate portions. Scanning device.

  (3) The optical scanning device according to (1) or (2), the photosensitive member scanned by the light beam from the optical scanning device, and the electrostatic latent image formed on the photosensitive member are developed. An image forming apparatus.

  According to the present invention, it is possible to guarantee the high dustproof performance of the optical scanning device and the reliable operation of the shutter covering the upper part.

Schematic cross-sectional view of image forming apparatuses of Examples 1 to 3 The perspective view which shows the structure of the optical scanning device of Examples 1-3, and sectional drawing of an optical scanning device The perspective view which shows the optical box of Examples 1-3, and a shutter. Top view of shutter moving mechanism, shutter, and optical scanning device of first to third embodiments The figure explaining the cover structure of Examples 1-3. The figure explaining the cover structure of Example 1, and a gate part. The figure explaining the gate part of the cover of Example 1. Sectional drawing of cover and shutter of Example 1 The figure explaining the gate part of the cover of Example 2. FIG. 6 is a diagram illustrating a shutter configuration according to the third embodiment.

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

  Embodiments of the present invention will be described below with reference to the drawings.

[Outline of image forming apparatus]
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 each color of yellow (Y), magenta (M), cyan (C), and black (Bk). Is provided. Hereinafter, the symbols Y, M, C, and Bk representing each color are omitted unless necessary. The image forming unit 101 includes a photosensitive drum 102 that is a photosensitive member. Each image forming unit includes a charging device 103 that charges the photosensitive drum 102 and a developing device 104 that develops the electrostatic latent image on the photosensitive drum with toner. Each image forming unit further includes a cleaning device 111 that removes residual toner on the photosensitive drum from the photosensitive drum (on the photosensitive member).

  Each image forming unit constitutes a process cartridge in which the above-described photosensitive drum 102, charging device 103, developing device 104, and cleaning device 111 are integrated. This 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 102. The optical scanning device 200 may be arranged so as to expose the photosensitive drum 102 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 that expose the photosensitive drums 102Y, 102M, 102C, and 102Bk charged by the charging devices 103Y, 103M, 103C, and 103Bk, respectively. Exposure to light beams forms electrostatic latent images on the photosensitive drums 102Y, 102M, 102C, and 102Bk.

  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 at 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 device 111 according to the present exemplary embodiment includes a blade that contacts the photosensitive drum 102, and scrapes the toner remaining on the photosensitive drum with the blade, thereby collecting the residual toner.

  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 with respect to the rotation direction of the intermediate transfer belt 106 (the arrow direction (counterclockwise direction in the drawing)). 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 this blade, thereby removing toner remaining on the intermediate transfer belt 106 without being transferred to the recording medium. to clean up.

  Regarding the configuration described below, the embodiments are a monochrome image forming apparatus having one photosensitive drum, and an image forming apparatus that directly transfers toner images formed on a plurality of photosensitive drums to a recording medium. Also good.

[Outline of optical scanning device]
Next, the optical scanning device 200 will be described. FIG. 2A is a perspective view showing the configuration of the optical scanning device 200, and FIG. 2B is a cross-sectional view of the optical scanning device 200. In the following description, the rotation axis direction of the rotary polygon mirror 203 is the Z-axis direction, the main scanning direction which is the scanning direction of the light beam, or the longitudinal direction of the reflection mirror is the X-axis direction, and the direction perpendicular to the X-axis and Z-axis Is the Y-axis direction.

  As shown in FIG. 2A, light source units 202Y, 202M, 202C, and 202Bk are attached to the outer wall of the optical box 201 of the optical scanning device 200. The light source unit 202Y emits laser light LY that exposes the photosensitive drum 102Y, and the light source unit 202M emits laser light LM that exposes the photosensitive drum 102M. The light source unit 202C emits laser light LC that exposes the photosensitive drum 102C, and the light source unit 202Bk emits laser light LBk that exposes the photosensitive drum 102Bk.

  The light source units 202Y, 202M, 202C, 202Bk are arranged close to each other. Here, a plane crossing the rotating polygon mirror 203 with the rotation axis of the rotating polygon mirror 203 as a normal is defined as a virtual plane. The laser beam LY emitted from the light source unit 202Y and the laser beam LBk emitted from the light source unit 202Bk are incident on the reflecting surface of the rotary 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 light LC emitted from the light source unit 202C and the laser light LM emitted from the light source unit 202M take an optical path that is obliquely incident on the above-described virtual plane from the lower side in the gravitational direction. Incident on the reflecting surface.

  As shown in FIG. 2A, a rotary polygon mirror 203 having four reflecting surfaces is installed in the central portion of the optical box 201. At the time of image formation, the rotary polygon mirror 203 rotates the rotation axis indicated by the dotted line in FIG. 2A in the R1 direction.

  The laser beam LY emitted from the light source unit 202Y is incident on the reflecting surface of the rotary polygon mirror 203. The laser light 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 rotary 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 reflecting surface of the rotary 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 toward 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 rotary 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 reflecting surface of the rotary polygon mirror 203.

  The laser beams LY and LM deflected by the rotary 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 rotary 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 is a laser beam that scans the photosensitive drum 102C in the −X direction. Become.

  Next, the optical paths of the laser beams LY, LM, LC, and LBk deflected by the rotary polygon mirror 203 will be described with reference to FIG. As shown in FIG. 2B, inside the optical box 201, there are a rotating polygon mirror 203, lenses 206, 207, 208, 209, 210, 211, reflecting mirrors 212, 213, 214, 215, 216, 217, and the like. The optical member is accommodated. On the open surface of the upper part of the optical box 201, a rotating polygon mirror 203, the lenses described above, and a cover 218 for protecting the reflection mirrors are attached.

  The laser beam LY deflected by the rotary 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 dustproof window 223 that is a transparent 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 rotary polygon mirror 203 passes through the lens 206 and then enters the reflection mirror 213. The reflection mirror 213 reflects the incident laser light LM toward the reflection mirror 214. 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 220 is closed by a transparent dustproof window 224 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 rotating polygonal 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 beam LBk reflected by the reflection mirror 215 passes. The opening 222 is closed by a transparent dustproof window 226 that allows the laser beam LBk to pass therethrough. The laser beam LBk that has passed through the dustproof window 226 forms an image on the photosensitive drum 102Bk.

  The laser beam LC deflected by the rotating polygon mirror 203 passes through the lens 209 and then enters the reflection mirror 216. The reflection mirror 216 reflects the incident laser beam LC toward the reflection mirror 217. The laser beam LC reflected by the reflection mirror 216 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 217 passes. The opening 221 is closed by a transparent dustproof window 225 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.

[Overview of cover]
The cover 218 will be described with reference to FIG. Details of FIG. 6A will be described later. As shown in FIG. 2B, the optical box 201 secures the hermeticity inside the optical box 201 by attaching a cover 218. As shown in FIG. 6A, the cover 218 is provided with a plurality of hook portions 218a. As shown in FIG. 3, the cover 218 is attached to the optical box 201 by a snap fit structure in which the plurality of hook portions 218 a are engaged with the plurality of protrusions 220 a provided on the outer wall of the optical box 201. As shown in FIG. 6A, the cover 218 includes a recess 218b that is recessed toward the inside of the optical box 201, and a protrusion 218c that protrudes toward the outside of the optical box 201 (on the shutter 300 side). 218d is provided.

[Outline of 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 provided on the cover 218 shown in FIG. In order to perform maintenance of the image forming apparatus 100, when the process cartridge 101 is attached / detached by opening a maintenance door, toner may be scattered from the process cartridge 101 due to the attachment / detachment of the process cartridge 101. Therefore, at least when the process cartridge 101 is replaced, it is desirable that the shutter 300 covers the dustproof windows 223, 224, 225, and 226 of the cover 218.

  FIG. 3 is a perspective view showing the shutter 300 attached to the optical scanning device 200 so as to cover the cover 218. The shutter 300 is a single plate-like resin member that faces the cover 218, and is provided on the upper surface of the cover 218 of the optical scanning device 200. The shutter 300 is guided by four guide claws 228 provided on the cover 218 of the optical scanning device so as not to come off, and is a member that covers the dustproof windows 223, 224, 225, and 226 of the cover 218. 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. . Furthermore, the shutter 300 has an opening 326 through which the laser beam LBk that has passed through the dustproof window 226 passes.

  The shutter 300 is formed with a long hole 301 for attaching a spring 310 which is an elastic body to be described later. Further, the shutter 300 is formed with elongated holes 302 and 303, the convex portion 218 c of the cover 218 is inserted into the elongated hole 302, and the convex portion 218 d of the cover 218 is inserted into the elongated hole 303. Accordingly, 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 are engaged, respectively. It functions as a guide member limited in the axial direction.

  The shutter 300 is always urged by a spring 310 in a direction to shield the opening. During normal image formation, the shutter 300 is pushed in the opening direction by a moving mechanism described later. On the other hand, during maintenance, the shutter 300 returns to the shielding position, and the dustproof windows 223, 224, 225, and 226 of all the colors of the YMCK of the cover 218 are closed at the same time, and scattered matters such as toner adhere to the dustproof windows of the optical scanning device 200. prevent. Since the long holes 302 and 303 of the shutter 300 are long holes in the direction parallel to the Y axis of the shutter 300, the movement of the shutter 300 by the long holes 302 and 303 and the convex portions 218c and 218d is a reciprocating direction parallel to the Y axis. Regulated by Note that the shutter 300 may be attached to the image forming apparatus side. Further, the above-described convex portion may be provided on the shutter 300 side, the concave portion (insertion portion) corresponding to the above-described opening may be 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. .

[Outline of shutter moving mechanism]
FIG. 4 is a top view of the shutter moving mechanism, the shutter, and the optical scanning device as viewed from above. FIG. 4A shows a state where the shutter 300 is closed and the dustproof windows 223, 224, 225, and 226 of the cover 218 are shielded by the shutter 300. On the other hand, in FIG. 4B, since the shutter 300 is opened and is located at a position retracted from the optical path of the laser beam, the dustproof windows 223, 224, 225, 226 of the cover 218 are not shielded by the shutter 300, The open state is shown. The shutter moving mechanism is provided on the image forming apparatus 100 side. A rotating mechanism that constitutes a part of the shutter moving mechanism is composed of a rotating mechanism and a pressing portion 309. As shown in FIG. 4A, the rotation mechanism includes a rotation shaft 305, a rotation unit 306, a lever 307, and a lever 308. The rotating unit 306 and the levers 307 and 308 constitute one rotating member, and the levers 307 and 308 extend from the rotating unit 306. The rotating member constituted by the rotating unit 306, the lever 307, and the lever 308 can rotate in the clockwise direction and the counterclockwise direction about the rotating shaft 305 as the rotation center.

  Next, the spring 310 constituting a part of the shutter moving mechanism will be described with reference to FIG. As shown in FIG. 4A, the recess 218b of the cover 218 is provided with an engaging portion 218e that engages with one end of a spring 310 such as a coil spring. On the other hand, as shown in FIG. 4B, the shutter 300 is provided with an engaging portion 304 that engages with the other end of the spring 310. That is, the cover 218 and the shutter 300 are connected by the spring 310, and the shutter 300 is always urged by the spring 310 in the direction of shielding the opening. In the present embodiment, the spring 310 connects the cover 218 and the shutter 300, but may be configured to connect the optical box 201 and the shutter 300.

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

  FIG. 4A is a top view of the state before the collection toner container (not shown) is mounted on the image forming apparatus 100 as viewed from above the shutter 300. In this embodiment, the state of FIG. 4A shows a state in which the spring 310 is contracted, the shutter 300 shields the laser beam from the optical scanning device 200, and the shutter 300 is closed. Therefore, in FIG. 4A, the shutter 300 covers the dustproof windows 223, 224, 225, and 226 provided on the cover 218. Even if the laser beams LY, LM, LC, and LBk are emitted, Those laser beams are blocked by the shutter 300.

  On the other hand, FIG. 4B is a top view of the state in which a collection toner container (not shown) is mounted on the image forming apparatus 100 as viewed from above the shutter 300. When a collected toner container (not shown) is attached to the image forming apparatus 100 from the state of FIG. 4A, the slope of the pressing portion 309 provided in the collected toner container moves in the direction of the arrow in the drawing, so that the lever 307 is moved. , 308 rotate in the clockwise direction (the arrow direction in the figure). As a result, the spring 310 is extended, and the shutter 300 moves in the opening direction (the arrow direction shown in FIG. 4A), so that the state shown in FIG. 4B is obtained. In this embodiment, the state of FIG. 4B shows a state in which the shutter 300 is not opened and the shutter 300 is not shielded from the laser beam from the optical scanning device 200. Therefore, in FIG. 4B, the shutter 300 does not cover the dustproof windows 223, 224, 225, and 226 provided on the cover 218, and the laser beams LY, LM, LC, and LBk are in the opening 323 of the shutter 300. 324, 325, 326.

  On the other hand, at the time of maintenance, since the collected toner container (not shown) is surely removed, the pushing force by the pressing portion 309 is lost, and the shutter 300 returns to the shielding position (the state shown in FIG. 4A) by the spring 310. In this embodiment, a recovery toner container (not shown) is used as a method of rotating the levers 307 and 308. However, if the operation is performed prior to removing the process cartridge during maintenance, the recovery toner container is not necessarily required. Absent.

[Composition of cover]
FIG. 5A is a diagram illustrating the configuration of the cover 218 in the present embodiment, and is a perspective view of the cover 218 viewed from the optical box 201 side. In FIG. 5A, the cover 218 is provided with a plurality of hook portions 218a that form a snap-fit structure by engaging protrusions 220a provided on the outer wall of the optical box 201. The cover 218 is provided with dustproof windows 223, 224, 225, and 226. Further, the cover 218 is provided with a seal portion 250 made of a polyolefin-based hot melt adhesive (hereinafter referred to as “hot melt”) on the entire circumference facing the outer peripheral edge of the optical box 201 when mounted on the optical box 201. It is formed by injection molding. Further, although four gate portions 250a for injecting hot melt at the time of injection molding are provided in FIG. 5A, at least one or more gate portions 250a may be provided.

  The seal portion 250 is formed on the cover 218 by injecting a polyolefin-based hot melt into a space between the formed cover 218 and a mold that is in contact with the cover 218. FIG. 5B is a view in which the cover 218 is cut at the position of the arrow shown in FIG. 5A, and is a cross-sectional view showing the relationship between the cover 218 and the seal portion 250. In FIG. 5B, the cover 218 is provided with a groove portion 218f, and the seal portion 250 is formed by filling the groove portion 218f with hot melt. An anchor groove 218g having a smaller width and a shallower depth is provided in the groove portion 218f, and the contact area between the cover 218 and the seal portion 250 is increased. Thereby, the adhesiveness between the cover 218 and the seal part 250 is ensured so that the seal member is not unintentionally peeled off from the cover 218. In addition, a concave groove is formed on the surface of the seal portion 250, and the outer periphery of the optical box 201 is inserted into the groove, so that the optical box 201 is sealed.

[Configuration of gate part]
FIG. 6A is a diagram illustrating the configuration of the cover 218 in the present embodiment, and is a perspective view of the cover 218 viewed from above. The cover 218 is provided with a plurality of hook portions 218a, and the cover 218 is attached to the optical box 201 by engaging each of the plurality of hook portions 218a with a plurality of protrusions 220a provided on the outer wall of the optical box 201. It is done. Further, the cover 218 is provided with a recess 218 b that is recessed toward the inside of the optical box 201 and a protrusion 218 c and 218 d that protrudes toward the outside of the optical box 201. Then, by engaging the convex portions 218c and 218d with the elongated holes 302 and 303 of the shutter 300, respectively, the convex portions 218c and 218d function as guide members that limit the moving direction of the shutter 300 to a predetermined direction. Furthermore, four gate portions 250 a for injecting molding material at the time of injection molding of the seal portion 250 are provided on the upper surface of the cover 218. When the hot melt is filled in the seal portion 250 constituted by a narrow and long space as in this embodiment, the heater is also used for the injection nozzle for injecting the hot melt in order to improve the fluidity of the hot melt. The injection material is maintained at a high temperature. For this reason, an injection nozzle will enlarge. On the other hand, usually, the cover 218 is often provided with a standing wall on the optical box 201 side or a protrusion (for example, a hook portion 218a) for fixing to the optical box 201 along the periphery. FIG. 7 is a view in the case where an injection port for injecting hot melt is provided in the gate portion 250a provided on the optical box side of the cover 218. The hatched circular portion is an injection nozzle for injecting hot melt. The nozzle range is shown. As described above, since the injection nozzle is provided with a heater, the nozzle shape becomes large, and as shown in FIG. 7, the projection such as the hook portion 218a provided on the outer peripheral portion of the cover 218 interferes with the injection nozzle. There is a case. Therefore, in order to avoid this, in this embodiment, the hot melt inlet of the gate portion 250a is provided on the upper surface of the cover 218.

  By the way, when hot melt is injected, since the hot melt has high fluidity, the molding material accumulates so as to pull the yarn, and protrudes into the injection port of the gate portion 250a as a convex gate mark. There is a case. FIG. 8 is a cross-sectional view in which the cover 218 and the shutter 300 are cut at a portion including the gate portion 250a. In FIG. 8, the shutter 300 is in an open state, and scanning light that is laser light from the optical box 201 passes through dustproof windows 223, 224, 225, and 226 provided on the cover 218, and the openings 323 and 324 of the shutter 300. 325, 326. 8A shows a gate mark when the inlet of the gate portion 250a is provided on the surface of the cover 218, and FIG. 8B shows a surface (one step) where the inlet of the gate portion 250a is lowered by one step from the surface of the cover 218. It is a figure which shows the gate trace at the time of providing in a low surface. If the surface of the gate portion 250a is flush with the surrounding cover surface as shown in FIG. 8 (a), even if the gate trace protrudes toward the shutter 300 even slightly, the gate trace interferes with the shutter 300, and the shutter 300 In the drawing, the movement in the shutter moving direction indicated by the arrow is obstructed. In this case, for example, secondary processing such as cutting and flattening the protruding portion of the gate trace with a blade is necessary, and labor and cost are generated.

  Therefore, in this embodiment, in order to avoid labor and cost, the gate portion 250a is provided on the surface of the cover 218 as shown in FIG. FIG. 6B is an enlarged view of the cover 218 surrounded by a circle in FIG. In FIG. 6B, the gate portion 250a is provided in a recess provided on the surface of the cover 218, and a hot melt inlet 250b is provided at the center of the gate portion 250a. FIG. 8B shows the state of FIG. 6B in a cross-sectional view. As shown in FIG. 8B, the surface of the gate portion 250a is provided in a recess that is one step lower than the surface of the cover 218. I understand that. Thereby, even if the gate trace protrudes from the injection port 250b, it does not interfere with the shutter 300, and the movement in the moving direction of the shutter 300 indicated by an arrow in the figure is not hindered. Specifically, in this embodiment, for example, even if the gate mark protrudes by 1 mm, it does not interfere with the shutter 300, and 1 mm is a protrusion amount that can be sufficiently managed by the discharge control at the time of molding. And so on.

  As described above, according to this embodiment, it is possible to guarantee the high dustproof performance of the optical scanning device and the reliable operation of the shutter that covers the upper portion. In an optical scanning device that combines a cover member that is integrally provided with a seal portion 250 by injection molding and a shutter that slides and moves on the upper surface of the cover, a gate portion is provided in a recess that is one step lower than the surface of the cover. . As a result, even if the convex gate trace protrudes from the gate portion, the shutter can be opened and closed reliably without interfering with the shutter and hindering the sliding operation of the shutter, and the smooth movement of the shutter is ensured. be able to.

[Configuration of gate part]
FIG. 9 is an enlarged view of a portion of the cover 218 surrounded by a circle in FIG. 6A, and is a diagram showing a configuration of the gate portion in the present embodiment. In FIG. 9, a concave portion is provided in the center of the gate portion 250a, and an injection port 250c for the molding material of the seal portion 250 is provided in the concave portion. In FIG. 9 of the present embodiment, the surface of the injection port 250c into which the hot melt is injected is in a position that is one step lower than that in FIG. 6B of the first embodiment. Therefore, in this embodiment, the injection port 250c is provided at a position lower than the position of the gate surface shown in FIG. As a result, the clearance to the shutter 300 can be made larger with respect to the protrusion of the gate trace in a limited space.

  As described above, according to this embodiment, it is possible to guarantee the high dustproof performance of the optical scanning device and the reliable operation of the shutter that covers the upper portion.

  In the first and second embodiments, the example in which the hot melt injection port of the gate portion 250 a is provided at a position lower than the surface of the cover 218 so that the gate trace does not interfere with the shutter 300 has been described. In the third embodiment, a configuration of the shutter 300 that prevents the gate trace from interfering with the shutter 300 will be described. In addition, the structure of the cover 218 in a present Example is the same as that of Fig.6 (a), and abbreviate | omits description.

[Configuration of shutter]
FIG. 10 is a diagram illustrating a configuration of the shutter 300 according to the present exemplary embodiment, and is a perspective view of the shutter 300 viewed from the cover 218 side. In FIG. 10, the shutter 300 includes openings 323, 324, 325, and 326 that allow the laser light that has passed through the dustproof windows 223, 224, 225, and 226 to pass therethrough as described above. Further, the shutter 300 includes long holes 301 for attaching the springs 310 and long holes 302 and 303 that are engaged with the convex portions 218c and 218d of the cover 218 and function as guide members. Further, in this embodiment, the shutter 300 is provided with a recess 300e at a position facing the gate portion 250a of the cover 218. FIG. 10 corresponds to the gate portion 250a shown in FIG. Four recesses 300e are provided. The recess 300e has a depth and width (length in a direction orthogonal to the shutter moving direction) such that the gate mark formed in the gate portion 250a does not interfere with the shutter 300. As a result, the gate trace formed on the gate portion 250a of the cover 218 abuts against the shutter 300, thereby preventing interference. In the present embodiment, the gate portion 250a has been described based on the configuration described in the first embodiment. However, the configuration of the gate portion 250a in the second embodiment can also be applied. Further, by associating the depth and width of the recess 300e, for example, the present embodiment can be applied even when the gate portion 250a is provided on the surface of the cover 218 at the same height as the cover 218.

  As described above, according to this embodiment, it is possible to guarantee the high dustproof performance of the optical scanning device and the reliable operation of the shutter that covers the upper portion.

200 Optical Scanning Device 201 Optical Box 218 Cover 250a Gate Part 300 Shutter

Claims (8)

A light source;
Deflecting means for deflecting the light beam emitted from the light source;
An optical member for guiding the light beam deflected by the deflecting means to the photosensitive member;
An optical box to which the light source is attached, the deflection means, and the optical member are housed therein;
A cover having a transparent window through which the light beam passes, and covering an open surface of the optical box;
A shutter that is disposed between the photoconductor and the cover and moves between a position retracted from an optical path of a light beam that has passed through the transparent window and a position that covers the transparent window;
An optical scanning device comprising:
The cover includes a seal member molded integrally with the cover at a portion that contacts the optical box,
An optical scanning device, wherein a gate portion for molding the seal member is provided in a concave portion provided on a surface of the cover facing the shutter.   The optical scanning device according to claim 1, wherein one or more gate portions are provided on the cover.   The optical scanning device according to claim 1, wherein an injection port for injecting a molding material to mold the seal member is provided in the concave portion. The recess has a further recess therein;
The optical scanning device according to claim 1, wherein an injection port for injecting a molding material to mold the seal member is provided in the further recess.   5. The optical scanning device according to claim 3, wherein the molding material is injected by an injection nozzle having a heater that maintains the molding material in a high temperature state. 6. A light source;
Deflecting means for deflecting the light beam emitted from the light source;
An optical member for guiding the light beam deflected by the deflecting means to the photosensitive member;
An optical box to which the light source is attached, the deflection means, and the optical member are housed therein;
A cover having a transparent window through which the light beam passes, and covering an open surface of the optical box;
A shutter that is disposed between the photoconductor and the cover and moves between a position retracted from an optical path of a light beam that has passed through the transparent window and a position that covers the transparent window;
An optical scanning device comprising:
The cover includes one or more gate portions for molding a seal member molded integrally with the cover at a portion in contact with the optical box,
The optical scanning device, wherein the shutter includes a concave portion at a position facing each of the gate portions. An optical scanning device according to any one of claims 1 to 6,
The photoconductor scanned by a light beam from the optical scanning device;
Developing means for developing an electrostatic latent image formed on the photoreceptor;
An image forming apparatus comprising:   The image forming apparatus according to claim 7, wherein the optical scanning device is disposed below the photoconductor in the direction of gravity and exposes the photoconductor with a light beam that has passed through the transparent window.

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