JP2011154255A - Optical scanning device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical scanning device and an image forming device, suppressing dirt of an exit window and suppressing the temperature increase in the devices. <P>SOLUTION: An open hole 64 is provided above a polygon scanner 50 of a shutter member 60. Outside air blown from a blowing fan 70 is guided in the open hole 64 by an airflow guide 62 and flows on the upper surface of a deflector cover 105. The outside air flowing on the upper surface of the deflector cover 105 removes heat radiated from the upper surface of the deflector cover 105 and then it is discharged through the open hole 64, a passing hole 63C, or an end in the main scanning direction of the shutter member 60. Thereby, the detention of the outside air around the deflector cover 105 is suppressed and the decrease of heat radiation efficiency of the deflector cover 105 is suppressed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an optical scanning device and an image forming apparatus.

  A so-called tandem type color image forming apparatus is known that forms images of different colors (visible images) on a plurality of latent image carriers and superimposes these images on each other to form a color image. This image forming apparatus forms a latent image on a latent image carrier by irradiating the surface of each latent image carrier, which is a surface to be scanned, with writing light corresponding to the image information and scanning it. To develop an image.

  In this tandem type image forming apparatus, a counter scanning type optical scanning apparatus is generally used as an optical scanning apparatus that irradiates each latent image carrier with a writing light, which is a light beam corresponding to image information, and scans it. Used.

  The opposed scanning type optical scanning device includes a polygon scanner which is composed of a polygon mirror as a rotating deflector, a polygon motor for rotating the polygon mirror, and a circuit board for controlling the driving of the polygon motor at the substantially center of the optical scanning device. Install. Then, a scanning lens or reflecting mirror, which is an optical element, is arranged so as to be line symmetric with respect to a single symmetry line drawn through the polygon mirror rotation center and perpendicular to the polygon mirror rotation axis direction. is doing. Further, the optical scanning device is arranged in the image forming apparatus so that the same number of latent image carriers as the left and right are arranged with respect to the arrangement position of the polygon mirror when viewed from the axial direction of the latent image carrier. A light source corresponding to each latent image carrier is attached to the housing of the optical scanning device.

  Among a plurality of light sources, light emitted from a certain light source is deflected and scanned by a polygon mirror, enters an optical element located on the left side with respect to the position of the polygon mirror, and passes through dust-proof glass as an exit window. The latent image carrier disposed on the left side with respect to the position of the polygon mirror is irradiated. Of the plurality of light sources, light emitted from another light source is incident on the other optical element located on the right side of the polygon mirror arrangement position, passes through the dust-proof glass, and reaches the polygon mirror arrangement position. The latent image carrier arranged on the right side is irradiated.

  In recent years, there has been a demand for higher image quality in image forming apparatuses, and in optical scanning apparatuses, dirt such as dust and toner adheres to each dust-proof glass, and the problem that image quality deteriorates due to shielding of laser light has become serious. I came. Patent Document 1 describes an optical scanning device provided with a shutter mechanism that covers a plurality of dust-proof glasses.

FIG. 11 is a schematic configuration diagram showing an optical writing unit 215 having a shutter mechanism described in Patent Document 1, together with four photoconductors 209a, 209b, 209c, and 209d. In this figure, the shutter member 214 is located at the open position.
As shown in FIG. 11, a plate-like shutter member 214 is perpendicular to the main scanning direction on the upper cover 211 as a window forming surface provided with a plurality of dustproof glasses 208a, 208b, 208c, 208d of the optical scanning device 215. It is slidably mounted in the direction of The shutter member 214 has three openings 218 provided in parallel with the main scanning direction so as to allow scanning light to pass through. As shown in FIG. 11, in the shutter open position, the three openings 218 are located at positions facing the dustproof glasses 208b, 208c, and 208d. In FIG. 11, the opening corresponding to the dustproof glass 208a at the left end is not provided in the shutter member 214, and the dustproof glass 208a is opened when the left end portion of the shutter member 214 in the drawing is located on the right side of the dustproof glass 208a. Is done. Thus, when the shutter member 214 is in the open position, the scanning lights L1 to L4 pass through the dust-proof glasses 208a, 208b, 208c, and 208d and are irradiated to the photosensitive members 209a, 209b, 209c, and 209d.

  Then, when the shutter member 214 moves in the A2 direction from the open position in FIG. 11, each opening 218 of the shutter member 214 is displaced from the position facing the dustproof glass 208b, 208c, 208d, and the left end of the shutter member 214 in the figure. The part moves to a position facing the dust-proof glass 208a, so that all the dust-proof glass 208a, 208b, 208c, and 208d are covered with the shutter member 214.

  Thereby, it is possible to suppress dirt and toner from adhering to the dustproof glasses 208a, 208b, 208c, and 208d when the apparatus is stopped.

  However, in the optical scanning device 215 described in Patent Document 1, since the upper cover 211 is covered with the shutter member 214, the following problem occurs.

  When deflecting the laser beam, the polygon mirrors 201a and 201b are rotated at a high speed, and the bearings of the polygon motor generate heat. The generated heat is radiated to the outside of the apparatus through the portion of the upper cover 211 facing the polygon scanner 201, thereby suppressing the inside of the optical scanning apparatus from becoming a high temperature. However, in Patent Document 1, since the upper cover 211 is covered with the shutter member 214 as described above, the heat radiated from the upper cover 211 stays between the upper cover 211 and the shutter member 214. . As a result, the heat dissipation efficiency from the upper cover 211 as the window forming surface is lowered, the inside of the optical scanning device becomes high temperature, and there is a possibility that optical parts such as an imaging lens are thermally deformed. When the optical system component is thermally deformed, there arises a problem that the writing light cannot be imaged on the surface of the photosensitive member. Further, there is a problem in that the color misregistration occurs because the irradiation position on the surface of each photoconductor is deviated.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an optical scanning device and an image forming apparatus capable of suppressing the contamination of the exit window and suppressing the temperature rise in the apparatus. That is.

In order to achieve the above object, the invention according to claim 1 is directed to deflecting and scanning light emitted from a light source by a rotary deflector and emitting the light from an exit window of an optical housing that houses the light source and the rotary deflector. In an optical scanning device that scans a surface to be scanned, the optical housing is disposed to face the window forming surface on which the exit window is formed, and moves parallel to the window forming surface to shield and open the exit window. And an airflow guide for allowing air to flow between the shutter member and the window forming surface.
According to a second aspect of the present invention, there is provided the optical scanning device according to the first aspect, wherein the optical scanning device includes a plurality of the light sources, passes through the rotation center of the rotary deflector, and is an axis of the rotary shaft of the rotary deflector. At least a pair of optical elements arranged symmetrically with respect to a symmetry line drawn in a direction orthogonal to the direction, and an exit window, and the light emitted from at least one of the plurality of light sources is one of the light beams by the rotary deflector. Light that is incident on an optical element, exits from one exit window, and exits from another light source is incident on the other optical element by the rotary deflector and is emitted from the other exit window. An optical scanning device, wherein the shutter member is provided from the one exit window to the other exit window, and shields and opens the exit windows.
According to a third aspect of the present invention, in the optical scanning device according to the second aspect, the shutter member has an opening hole that opens a portion of the window forming surface of the optical housing that faces the rotary deflector. The airflow guide is provided at the end of the hole.
According to a fourth aspect of the present invention, in the optical scanning device of the third aspect, a wall portion for allowing air to flow into the airflow guide is provided on the shutter member.
According to a fifth aspect of the present invention, in the optical scanning device according to any one of the first to fourth aspects, the shutter member and the airflow guide are integrally formed of resin.
According to a sixth aspect of the present invention, in the optical scanning device according to any one of the first to fourth aspects, the shutter member is formed of a sheet metal, and the airflow guide is formed by bending.
According to a seventh aspect of the present invention, in the optical scanning device according to any of the first to fourth aspects, the airflow guide is formed by attaching a resin plate to a shutter member.
According to an eighth aspect of the present invention, in the optical scanning device according to any one of the first to seventh aspects, the shutter member is provided with a cleaning member that cleans the emission window while rubbing against the emission window. Is.
According to a ninth aspect of the present invention, there is provided a plurality of light sources, a rotary deflector that deflects and scans light emitted from the plurality of light sources in the main scanning direction, and a rotation center of the rotary deflector. A light beam emitted from at least one of a plurality of light sources includes at least a pair of optical elements and an emission window arranged symmetrically with respect to a symmetry line drawn in a direction orthogonal to the axial direction of the rotation axis. The opposite scanning method in which the light that is incident on one optical element and exits from one exit window and the light emitted from another light source is incident on the other optical element by the rotary deflector and exits from one exit window. In this optical scanning device, the optical housing in which the pair of optical elements, the rotary deflector, and the light source are housed is disposed to face a window forming surface on which a plurality of exit windows are formed, and the window forming surface is opposed to the window forming surface. parallel The shutter member has a shutter member that moves and shields and opens the plurality of exit windows, and an opening hole that opens a portion of the window forming surface of the optical housing that faces the rotary deflector is provided in the shutter member. It is a feature.
According to a tenth aspect of the present invention, in the image forming apparatus provided with the optical writing means for writing the latent image on the surface of the latent image carrier, the optical scanning according to any one of the first to ninth aspects is used as the optical writing means. An apparatus is used.
According to an eleventh aspect of the present invention, there is provided the image forming apparatus according to the tenth aspect, further comprising a blowing unit for blowing outside air to the airflow guide.

According to the first aspect of the present invention, air flows between the shutter member and the window forming surface by causing the airflow guide to cause air to flow between the shutter member and the window forming surface. The air flowing between the shutter member and the window forming surface takes away the heat released from the window forming surface, and finally flows out from the facing portion between the end of the shutter member and the window forming surface. . Thereby, it can suppress that heat retains between a shutter member and a window formation surface, and can suppress that the thermal radiation efficiency from a window formation surface falls. As a result, it is possible to suppress the inside of the apparatus from becoming high temperature and to suppress thermal deformation of the optical element.
Further, by shielding the exit window with the shutter member, it is possible to suppress dust, toner, and the like from adhering to the exit window, and it is possible to suppress contamination of the exit window.

According to the ninth aspect of the present invention, since the shutter member is provided with the opening hole that opens the portion facing the rotation deflector of the window forming surface of the optical housing, the portion of the window forming surface facing the rotation deflector is provided. The heat from the rotary deflector radiated from the heat is radiated through the opening hole. As a result, the heat from the rotating deflector radiated from the portion of the window forming surface facing the rotating deflector is prevented from staying between the window forming surface and the shutter member, and the heat dissipation efficiency from the window forming surface Can be suppressed. As a result, it is possible to suppress the inside of the apparatus from becoming high temperature and to suppress thermal deformation of the optical element.
Further, by shielding the exit window with the shutter member, in order for floating toner and dust to adhere to the exit window, the shutter member and the window formation are formed through the opening hole between the shutter member and the window forming surface. Need to move between planes. Therefore, the floating toner or dust is likely to adhere to the window forming surface or the surface facing the window forming surface of the shutter member before adhering to the exit window. Thereby, compared with the case where the exit window is always exposed, it is possible to suppress dust, toner, and the like from adhering to the exit window, and to prevent the exit window from being soiled.

1 is a schematic configuration diagram illustrating a printer according to an embodiment. FIG. 2 is a schematic configuration diagram illustrating an image forming station for Y in the printer. FIG. 2 is a schematic configuration diagram showing an optical writing unit in the printer together with four photosensitive members. The top view of the optical writing unit. The perspective view of the optical writing unit. The schematic block diagram when the shutter member in the optical writing unit exists in a closed position. FIG. 10 is a schematic configuration diagram showing an optical writing unit of Modification 1 together with four photoconductors. FIG. 10 is a schematic configuration diagram showing an optical writing unit of Modification 2 together with four photoconductors. FIG. 10 is a schematic configuration diagram showing an optical writing unit of Modification 3 together with four photoconductors. FIG. 10 is a schematic configuration diagram of an optical writing unit according to Modification 4; FIG. 6 is a schematic configuration diagram showing a conventional optical writing unit together with four photoconductors.

Hereinafter, an embodiment in which the present invention is applied to an electrophotographic color laser printer (hereinafter simply referred to as a printer) will be described.
FIG. 1 is a schematic configuration diagram illustrating a printer according to the present embodiment. The printer includes a housing 1 and a paper feed cassette 2 that can be pulled out from the housing 1. Image forming stations 3Y, 3C, and 3C for forming toner images (visible images) of each color of yellow (Y), cyan (C), magenta (M), and black (K) are provided at the center of the housing 1. 3M, 3K. Hereinafter, the subscripts Y, C, M, and K of the respective symbols indicate members for yellow, cyan, magenta, and black, respectively.

FIG. 2 is a schematic configuration diagram showing an image forming station for yellow (Y). The other image forming stations have the same configuration.
As shown in FIGS. 1 and 2, the image forming stations 3Y, 3C, 3M, and 3K include drum-shaped photoconductors 10Y, 10C, 10M, and 10K as latent image carriers that rotate in the direction of arrow A in the drawing. ing. Each of the photoreceptors 10Y, 10C, 10M, and 10K includes an aluminum cylindrical substrate having a diameter of 40 [mm] and an OPC (organic photo semiconductor) photosensitive layer that covers the surface of the photoreceptor. Each of the image forming stations 3Y, 3C, 3M, and 3K includes charging devices 11Y, 11C, 11M, and 11K that charge the photoconductors around the photoconductors 10Y, 10C, 10M, and 10K, respectively. Further, developing devices 12Y, 12C, 12M, and 12K as developing means for developing the latent image formed on the photosensitive member, and cleaning devices 13Y, 13C, 13M, and 13K for cleaning residual toner on the photosensitive member are also provided around the photosensitive member. In preparation.

  Below each of the image forming stations 3Y, 3C, 3M, and 3K, there is provided an optical writing unit 4 as an optical scanning device that performs optical scanning with the writing light L on the photoreceptors 10Y, 10C, 10M, and 10K. Yes. Further, an intermediate transfer unit 5 including an intermediate transfer belt 20 to which toner images formed by the image forming stations 3Y, 3C, 3M, and 3K are transferred above the image forming stations 3Y, 3C, 3M, and 3K. It has. Further, a fixing unit 6 is provided for fixing the toner image transferred to the intermediate transfer belt 20 onto a recording paper P as a transfer member. In addition, toner bottles 7Y, 7C, 7M, and 7K that store toners of each color of yellow (Y), cyan (C), magenta (M), and black (K) are loaded on the top of the housing 1. . The toner bottles 7 </ b> Y, 7 </ b> C, 7 </ b> M, and 7 </ b> K can be detached from the housing 1 by opening a paper discharge tray 8 formed on the top of the housing 1.

  An optical writing unit 4 as an optical scanning device has a semiconductor laser as a light source, and writing light L as a light beam is directed from this semiconductor laser toward a polygon mirror having a regular polygonal column structure that is rotationally driven. Fire. The emitted writing light L is reflected while being deflected in the main scanning direction by the mirror surface of the rotating polygon mirror. Then, after being folded by a plurality of reflecting mirrors, the peripheral surfaces of the photoreceptors 10Y, 10C, 10M, and 10K that are uniformly charged by the charging devices 11Y, 11C, 11M, and 11K are scanned. Thereby, electrostatic latent images for Y, C, M, and K are formed on the peripheral surfaces of the photoreceptors 10Y, 10C, 10M, and 10K as latent image carriers. The detailed description of the optical writing unit 4 will be described later.

  The intermediate transfer belt 20 of the intermediate transfer unit 5 serving as transfer means is driven to rotate counterclockwise in the figure at a predetermined timing while being wound around a drive roller 21, a tension roller 22 and a driven roller 23. In addition, the intermediate transfer unit 5 includes primary transfer rollers 24Y, 24C, 24M, and 24K that primarily transfer the toner images formed on the photoreceptors 10Y, 10C, 10M, and 10K to the intermediate transfer belt 20. Further, a secondary transfer roller 25 that transfers the toner image primarily transferred onto the intermediate transfer belt 20 to the recording paper P, and a belt that cleans residual toner on the intermediate transfer belt 20 that has not been transferred onto the recording paper P. A cleaning device 26 is also provided.

Next, a process for obtaining a color image in this printer will be described.
First, in the image forming stations 3Y, 3C, 3M, and 3K, the photoreceptors 10Y, 10C, 10M, and 10K are uniformly charged by the charging devices 11Y, 11C, 11M, and 11K. Thereafter, scanning exposure is performed with the writing light L generated based on the image information, and electrostatic latent images are formed on the surfaces of the photoreceptors 10Y, 10C, 10M, and 10K. These electrostatic latent images are developed with toners of the respective colors carried on the developing rollers 15Y, 15C, 15M, and 15K of the developing devices 12Y, 12C, 12M, and 12K, and are converted into Y, C, M, and K toner images. Become. The Y, C, M, and K toner images on the photoreceptors 10Y, 10C, 10M, and 10K are formed on the intermediate transfer belt 20 that is rotated counterclockwise by the action of the primary transfer rollers 24Y, 24C, 24M, and 24K. The primary transfer is carried out in order. The image forming operation of each color at this time is shifted in timing from the upstream side in the moving direction of the intermediate transfer belt 20 toward the downstream side so that the toner image is transferred to the same position on the intermediate transfer belt 20. Executed.

  The surfaces of the photoconductors 10Y, 10C, 10M, and 10K after the completion of the primary transfer are cleaned by the cleaning blades 13a of the cleaning devices 13Y, 13C, 13M, and 13K to prepare for the next image formation.

  The toner filled in the toner bottles 7Y, 7C, 7M, and 7K is placed in the developing devices 12Y, 12C, 12M, and 12K of the image forming stations 3Y, 3C, 3M, and 3K by a conveyance path (not shown) as necessary. A fixed amount is supplied.

  On the other hand, the recording paper P in the paper feed cassette 2 is transported into the housing 1 by a paper feed roller 27 disposed in the vicinity of the paper feed cassette 2 and is secondary by a registration roller pair 28 at a predetermined timing. It is conveyed to the transfer unit. Then, the toner image formed on the intermediate transfer belt 20 is transferred to the recording paper P in the secondary transfer portion. The recording paper P onto which the toner image has been transferred passes through the fixing unit 6 to fix the toner image, and is then discharged to the paper discharge tray 8 by the discharge roller 29. Similar to the photoconductor 10, the transfer residual toner remaining on the intermediate transfer belt 20 is cleaned by a belt cleaning device 26 that contacts the intermediate transfer belt 20.

Next, the optical writing unit 4 will be described.
3 is a schematic cross-sectional view showing the configuration of the optical writing unit 4, FIG. 4 is a schematic plan view of the optical writing unit 4, and FIG. 5 is a perspective view of the optical writing unit 4.
The optical writing unit 4 includes optical elements such as a polygon scanner 50, various reflection mirrors, and various lenses, which are housed in an optical housing 131. The upper opening of the optical housing 131 is covered with the upper cover 107. The upper cover 107 is provided with dustproof glasses 48Y, 48C, 48M, and 48K as exit windows through which the writing light passes, and includes an optical cover 106 that covers the mirrors 44 and 45, the scanning lens 43, and a polygon scanner. And a deflector cover 105 for covering. The optical cover 106 has an opening at a portion facing the polygon scanner, and a deflector cover 105 is attached to the opening.

  The polygon scanner 50 as a rotary deflector includes a polygon motor 51, and an upper polygon mirror 52b and a lower polygon mirror 52a each having a regular polygonal column shape fixed to a rotation shaft 51a of the polygon motor 51. The polygon scanner 50 is disposed substantially at the center of the optical writing unit 4 and is surrounded by a soundproof glass, a soundproof wall, and a deflector cover 105 (not shown).

  An M optical system and a K optical system are arranged on the right side of the polygon scanner 50 in the drawing. On the left side of the polygon scanner 50 in the drawing, an optical system for Y and an optical system for C are arranged. As shown in FIG. 4, the optical writing unit 4 is a position where the optical elements and the like are line symmetric with respect to a symmetric line drawn in a direction orthogonal to the axial direction of the rotation axis through the rotation center of the polygon mirror 52. Is a counter scanning type optical scanning device arranged in pairs. Specifically, the optical system for Y has a configuration that is line-symmetric with the optical system for K. In addition, the optical system for C is configured to have a line-symmetric relationship with the optical system for M.

  As shown in FIG. 4, semiconductor lasers 53K, 53M, 53C, and 53Y as light sources that emit writing light Lk, Lm, Lc, and Ly as light beams respectively corresponding to the photosensitive members 10K, 10M, 10C, and 10Y are provided. I have. The semiconductor laser 53K is arranged directly below the semiconductor laser 53M and is not shown. Further, the semiconductor laser 53Y is disposed directly below the semiconductor laser 53C and is not shown. A collimating lens, an aperture (not shown), and a cylindrical lens are arranged on the optical path from the semiconductor laser to the polygon mirror. The K-color collimating lens is not shown because it is directly below the M-color collimating lens 54M, and the K-color cylindrical lens is directly below the M-color cylindrical lens 55M. Similarly, the Y-color collimating lens is not shown because it is directly under the C-color collimating lens 54C, and the Y-color cylindrical lens is directly under the C-color cylindrical lens 55C.

  Further, as shown in FIG. 3, scanning lenses (fθ lenses) 43a and 43b, first mirrors 44K, 44M, 44C and 44Y, and second mirrors 45M and 45C, which are optical elements, are irradiated objects from the polygon scanner 50. It is arranged on the optical path to a certain photoconductor 10.

  The writing light Lk emitted from a K semiconductor laser (not shown) passes through a K collimator lens (not shown) and is then shaped into a fixed shape by a K aperture (not shown). Next, by passing through a cylindrical lens for K (not shown), the light is condensed in the sub-scanning direction (the direction corresponding to the moving direction of the photosensitive member surface on the photosensitive member surface) and incident on the side surface of the lower polygon mirror 52a. To do. When the writing light Lk is incident on the side surface of the lower polygon mirror 52a, the writing light Lk is deflected and scanned in the main scanning line direction. The writing light Lk deflected and scanned by the lower polygon mirror 52a is collected by the scanning lens 43a (fθ lens). The K writing light Lk collected by the scanning lens 43a is applied to the photoconductor 10K through the first mirror 44K.

  The writing light Lm emitted from the M semiconductor laser 53M, like the K color, passes through the M collimating lens 54M, the M aperture (not shown), the M cylindrical lens 55M, etc., and the upper polygon mirror 52b. Scanned. The M-color writing light Lm scanned by the upper polygon mirror 52b passes through the scanning lens 43a, the first mirror 44M, and the second mirror 45M, and irradiates the photoconductor 10M.

  The writing light Lc emitted from the C semiconductor laser 53C also passes through the C collimating lens 54C, the C aperture (not shown), the C cylindrical lens 55C, etc., and is scanned by the upper polygon mirror 52b. . The C-color writing light Lc scanned by the upper polygon mirror 52b passes through the scanning lens 43b, the first mirror 44C, and the second mirror 45C and is irradiated onto the photoconductor 10C.

  The writing light Ly emitted from the Y semiconductor laser (not shown) also passes through the Y collimating lens (not shown), the Y aperture (not shown), the Y cylindrical lens (not shown), etc. It is scanned by the mirror 52a. The Y-color writing light Ly scanned by the lower polygon mirror 52a passes through the scanning lens 43b and the first mirror 44Y and is irradiated to the photoreceptor 10Y.

  Further, as shown in FIG. 3, the shutter member 60 is slidably and integrally mounted on the upper cover 107 (the optical cover 106 and the deflector cover 105). As shown in FIG. 5, the shutter member 60 has two guide holes 69 extending in a direction orthogonal to the main scanning direction (longitudinal direction of the optical writing unit 4). In each guide hole 69, a stepped screw 68 is screwed to the upper cover 107 so as to press the shutter member 60. Thereby, the shutter member 60 is supported by the upper cover 107 so as to be able to reciprocate.

  The shutter member 60 is provided with four passage holes 63Y, 63C, 63M, and 63K for allowing the writing light extending parallel to the main scanning direction to pass therethrough. As shown in FIG. 3, one end of a shielding plate 66Y, 66C, 66M, 66K is attached to the opening end of each passage hole 63Y, 63C, 63M, 63K, and the other end is provided with dustproof glass 48Y, Cleaning members 67Y, 67C, 67M, and 67K that clean the surfaces of the dust-proof glasses 48Y, 48C, 48M, and 48K by rubbing with 48C, 48M, and 48K are attached. As shown in FIG. 3, when the shutter member 60 is in the open position, the cleaning members 67Y, 67C, 67M, and 67K are in contact with the left ends of the dustproof glasses 48Y, 48C, 48M, and 48K in the drawing.

  A drive mechanism (not shown) is provided on one end side in the longitudinal direction of the shutter member 60. By driving the drive mechanism (not shown), the shutter member 60 in the open position is shown in FIG. Move to the closed position as shown in FIG. At this time, the cleaning members 67Y, 67C, 67M, and 67K rub against the surfaces of the dust-proof glasses 48Y, 48C, 48M, and 48K, and the toner and dust adhered to the surfaces of the dust-proof glasses 48Y, 48C, 48M, and 48K. Remove.

  When the optical writing unit is not in operation, as shown in FIG. 6, the shutter member 60 is in the closed position, and the shielding plates 66Y, 66C, 66M, 66K cover the dust-proof glasses 48Y, 48C, 48M, 48K. . Thereby, it is possible to prevent the toner and dust from adhering to the surfaces of the dust-proof glasses 48Y, 48C, 48M, and 48K. In particular, in the present embodiment, as shown in FIG. 1, since the optical writing unit 4 is arranged below the image forming stations 3Y, 3C, 3M, and 3K, the image forming stations 3Y, 3C, 3M, and 3K are arranged. Then, the toner falls to the optical writing unit 4 and the toner easily adheres to the dustproof glasses 48Y, 48C, 48M, and 48K. Therefore, when the optical writing unit is not in operation, the dustproof glasses 48Y, 48C, 48M, and 48K are covered with the shielding plates 66Y, 66C, 66M, and 66K, so that the image forming stations 3Y and 3C are formed on the dustproof glasses 48Y, 48C, 48M, and 48K. , 3M, 3K can be prevented from adhering to the toner that has fallen off, which is effective. When irradiating the photoconductors 10Y, 10C, 10M, and 10K with writing light, the shutter member 60 is moved to the left side in the drawing from the state where the shutter member 60 shown in FIG. Position to open position as shown. As a result, the writing light emitted from each light source passes through the dust-proof glasses 48Y, 48C, 48M, and 48K and the through holes 63Y, 63C, 63M, and 63K, and is irradiated to the respective photoreceptors 10Y, 10C, 10M, and 10K. The

  The polygon motor 51 generates heat because it rotates at high speed when deflecting and scanning the writing light. The deflector cover 105 is made of a heat conductive material having good heat conductivity such as metal, and heat from the polygon scanner 50 is radiated to the outside of the apparatus via the deflector cover 105, and soundproofing (not shown) is performed. The space surrounded by the glass, the sound barrier, and the deflector cover 105 is prevented from becoming high temperature. At this time, if the shutter member 60 covers the deflector cover 105, the heat radiated from the deflector cover 105 stays between the deflector cover 105 and the shutter member 60. As a result, the heat dissipation efficiency from the deflector cover 105 is lowered, the space surrounded by the soundproof glass, the soundproof wall, and the deflector cover 105 (not shown) becomes high temperature, the optical housing 131 is thermally deformed, and the polygon scanner 50 There is a risk that the image will be disturbed, for example, when the axis of rotation of the rotation axis collapses.

  In the present embodiment, an open hole 64 is provided above the polygon scanner 50 of the shutter member 60. As a result, the heat radiated from the deflector cover 105 is radiated through the opening hole 64, so that the heat radiated from the deflector cover 105 stays between the deflector cover 105 and the shutter member 60. Can be suppressed. Thereby, it can suppress that the thermal radiation efficiency of the deflector cover 105 falls, and can suppress that the space enclosed by the soundproof glass not shown and the soundproof wall and the deflector cover 105 becomes high temperature. .

  Further, in the present embodiment, as shown in FIGS. 1 and 3 to 6, as a blowing means for letting outside air flow between the image forming stations 3 Y, 3 C, 3 M, and 3 K and the optical writing unit 4. A fan 70 is provided. Further, the shutter member 60 is provided with an airflow guide 62 that guides the outside air sent from the blower fan 70 to the opening hole 64 on the upper surface of the deflector cover 105. The airflow guide 62 has a shape that curves from the periphery of the opening hole 64 on the upper surface of the shutter member 60 and then curves toward the blower fan 70 side.

  The shutter member 60 and the airflow guide 62 are the same resin material and are integrally molded by injection molding or the like. In this manner, the shutter member 60 and the airflow guide 62 are integrally formed, so that the shutter member 60 and the airflow guide 62 are separate parts, and the airflow guide 62 is compared with the configuration in which the airflow guide 62 is attached to the shutter member 60. The operation of attaching to the shutter member 60 is not necessary, and the number of assembling steps can be reduced. Thereby, manufacturing cost can be reduced.

  As shown in FIG. 3, the outside air taken into the apparatus by the blower fan 70 flows on the upper surface of the shutter member 60 in parallel with the moving direction of the shutter member 60. The airflow flowing on the upper surface of the shutter member 60 flows into the upper surface of the deflector cover 105 by the airflow guide 62. The outside air that has flowed into the upper surface removes heat radiated from the upper surface of the deflector cover 105 and then escapes from the opening hole 64, the passage hole 63 </ b> C, and the end of the shutter member 60 in the main scanning direction. Thereby, it is possible to suppress the heat from staying around the deflector cover 105, and it is possible to further suppress the decrease in the heat dissipation efficiency of the deflector cover 105.

  Next, a modification of the optical writing unit 4 will be described.

[Modification 1]
FIG. 7 is a schematic configuration diagram of the optical writing unit 4-1 according to the first modification.
In the optical writing unit 4-1 of the first modification, the shutter member 60 is formed of sheet metal, and the airflow guide is formed by bending.
As shown in FIG. 7, the optical writing unit 4 of the first modification includes a first airflow guide 62-1 in which the blower fan 70 side of the open hole 64 end is bent to the deflector cover 105 side, and the open hole end. And a second airflow guide 62-2 in which the side opposite to the blower fan 70 side is bent to the photosensitive member side.

  Thus, by forming the shutter member 60 from sheet metal, the heat dissipation effect of the shutter member 60 can be enhanced as compared to the case where the shutter member 60 is formed from resin. Therefore, the heat radiated from the upper cover 107 is radiated through the shutter member 60, and the heat can be prevented from staying between the shutter member 60 and the upper cover 107. Thereby, compared with the case where the shutter member 60 is formed of resin, the inside of the optical housing 131 can be suppressed from becoming high temperature. Also, the shutter member 60 can be made thinner and the optical writing unit 4-1 can be made smaller than when the shutter member 60 is made of resin. Further, by forming the airflow guide 62 by bending, the rigidity of the shutter member 60 can be increased, and the shutter member 60 and the airflow guide 62 are formed separately, and the airflow guide 62 is provided on the shutter member 60. Compared with the case of assembling, the assembly man-hours can be reduced.

[Modification 2]
FIG. 8 is a schematic configuration diagram of the optical writing unit 4-2 of the second modification.
The optical writing unit 4-2 of the second modification is formed by sticking Mylar (registered trademark), which is a resin plate, to the shutter member 60 to form an airflow guide.
As shown in FIG. 8, the optical writing unit 4-2 of Modification 2 has Mylar (registered trademark) pasted on the air blowing fan 70 side and the air blowing fan 70 side at the end of the opening hole 64. Airflow guides 62a-1 and 62a-2 are formed. The first airflow guide 62a-1 made of Mylar (registered trademark) affixed to the end of the open hole is bent toward the deflector cover 105 side, and Mylar (registered trademark) affixed to the side opposite to the blower fan 70 side. The second airflow guide 62a-2 is bent to the photoconductor side.

  Thus, by forming the airflow guides 62a-1 and 62a-2 with Mylar (registered trademark), the structure of the shutter member 60 can be simplified, and the shutter member 60 can be made inexpensive. Moreover, the airflow guide 62 can be formed with an inexpensive material cost, and the cost of the apparatus can be suppressed.

[Modification 3]
FIG. 9 is a perspective view of the optical writing unit 4-3 of Modification 3 with the shutter member 60 removed.
As shown in the figure, in the optical writing unit 4-3 of the third modification, wall portions 71 extending upward are provided at both ends of the shutter member 60 in the main scanning direction. Thus, by providing the wall portion 71, it is possible to suppress the outside air sent from the blower fan 70 to the upper surface of the shutter member 60 from flowing out from both ends of the shutter member 60 in the main scanning direction. Accordingly, a large amount of outside air can be caused to flow into the airflow guide 62, and a large amount of outside air can be applied to the deflector cover 105. Therefore, it is possible to further suppress a decrease in the heat dissipation efficiency of the deflector cover 105.

[Modification 4]
FIG. 10 is a schematic configuration diagram of an optical writing unit 4-4 of the fourth modification.
As shown in the figure, the fourth modification is located on the side surface in the main scanning direction (short direction of the optical writing unit 4-4) of the apparatus and at a position facing the substantially center of the optical writing unit 4-4. A blower fan 70 is disposed. As a result, the outside air taken in by the blower fan 70 flows above the deflector cover 105 in the main scanning direction. As shown in the figure, an introduction hole 72 for guiding the outside air taken in by the blower fan 70 between the shutter member 60 and the deflector cover 105 is provided near the end of the shutter member 60 on the blower fan 70 side. An airflow guide 62 is provided. The airflow guide 62 is provided at the end of the introduction hole 72 opposite to the blower fan 70 side. As described above, the airflow guide 62 may be formed by attaching Mylar (registered trademark) to the end of the introduction hole 72 opposite to the blower fan side. When the shutter member 60 is a sheet metal, You may form by a bending process. Moreover, when the shutter member 60 is resin, you may shape | mold integrally by injection molding etc.

  The outside air taken in from the blower fan 70 and flowing in the main scanning direction is guided to the introduction hole 72 by the airflow guide 62 and flows between the shutter member 60 and the deflector cover 105 from the introduction hole 72. Thereby, it is possible to suppress the heat radiated from the deflector cover 105 from staying around the deflector cover 105, and it is possible to further suppress a decrease in the heat dissipation efficiency of the deflector cover 105.

  Further, in the configuration shown in FIG. 10, an introduction hole 72 is provided in the vicinity of the end of the shutter member 60 on the blower fan 70 side, and outside air is taken in between the shutter member 60 and the deflector cover 105. Similarly to the embodiments and the first to third modifications, an open hole may be provided above the polygon scanner 50 of the shutter member 60, and outside air may be taken in between the shutter member 60 and the deflector cover 105.

  In the above description, the upper cover 107 is composed of two members, ie, the deflector cover 105 and the optical cover, but may be composed of one cover member.

As described above, the optical writing unit 4 as the optical scanning device of the present embodiment deflects and scans the light emitted from the semiconductor laser as the light source by the polygon scanner 50 as the rotary deflector and emits it from the dust-proof glass 48 as the exit window. The photosensitive member 10 which is the surface to be scanned is scanned. Further, the optical writing unit 4 of the present embodiment is disposed so as to face the upper cover 107 (consisting of the optical cover 106 and the deflector cover 105) as a window forming surface on which the dustproof glass 48 is formed. The shutter member 60 moves horizontally and shields and opens the dust-proof glass 48. An airflow guide 62 for allowing air to flow between the shutter member 60 and the upper cover 107 is provided.
With such a configuration, the airflow guide 62 suppresses the heat from staying between the shutter member 60 and the upper cover 107 by allowing air to flow between the shutter member 60 and the upper cover 107. It is possible to prevent the heat dissipation efficiency from the upper cover 107 from being lowered. Thereby, it can suppress that the inside of an apparatus becomes high temperature, and can suppress the thermal deformation of an optical element. Further, by shielding the dust-proof glass 48 with the shutter member 60, it is possible to suppress dust and toner from adhering to the dust-proof glass 48, and to prevent the dust-proof glass 48 from being contaminated.

  Further, in the optical writing unit 4 of this embodiment, the optical element for K (scanning lens, mirror), the optical element for Y, the optical element for M, and the optical element for C are rotated by the polygon scanner 50. This is an optical scanning unit of an opposite scanning system that is arranged symmetrically with respect to a symmetry line drawn in a direction orthogonal to the axial direction of the rotation axis of the polygon scanner 50 through the center. The dust-proof glass for Y is symmetrically arranged with respect to the dust-proof glass for K and the above-mentioned symmetry line, and the dust-proof glass for M is symmetrically arranged with respect to the dust-proof glass for C and the symmetry line. The shutter member shields and opens the four dust-proof glasses 48Y, 48M, 48C, and 48K. Thereby, compared with the structure which provides a shutter member for every dustproof glass, a number of parts can be reduced and the cost of an apparatus can be aimed at.

  Further, according to the optical writing unit 4 of the present embodiment, the opening 64 is provided in a portion facing the polygon scanner 50 with the deflector cover 105 that is a part of the upper cover 107 of the shutter member 60 interposed therebetween. As a result, heat generated from the polygon scanner 50 is radiated from the opening hole 64 of the shutter member 60 via the deflector cover 105, and the heat is prevented from staying between the shutter member 60 and the deflector cover 105. Therefore, it is possible to suppress a decrease in the heat dissipation efficiency of the deflector cover 105. Further, since the airflow guide 62 is provided at the end of the opening hole 64, air flows into the deflector cover 105 from the opening hole 64 by the airflow guide 62. Thereby, it is possible to further suppress the heat from staying between the shutter member 60 and the deflector cover 105.

  Further, as shown in the third modification, the shutter member 60 is provided with a wall portion 71 for allowing air to flow into the airflow guide 62. Thereby, it can suppress that air (outside air) flows in into another part, and can flow much air (outside air) between the shutter member 60 and the upper cover 107 with an airflow guide.

  According to the present embodiment, since the shutter member 60 and the airflow guide 62 are integrally formed of resin, the shutter member 60 and the airflow guide 62 are separate components, and the airflow guide 62 is attached to the shutter member 60. In comparison with the above, it is not necessary to attach the airflow guide 62 to the shutter member 60, and the number of assembling steps can be reduced. Thereby, manufacturing cost can be reduced.

  Moreover, as shown in the modification 1, the shutter member 60 may be formed by sheet metal, and the airflow guide 62 may be formed by bending. By forming the shutter member 60 from sheet metal, the heat dissipation effect of the shutter member 60 can be enhanced compared to the case where the shutter member 60 is formed from resin. Therefore, the heat radiated from the upper cover 107 is radiated through the shutter member 60, and the heat can be prevented from staying between the shutter member 60 and the upper cover 107. Thereby, compared with the case where the shutter member 60 is formed of resin, the inside of the optical housing 131 can be suppressed from becoming high temperature. Also, the shutter member 60 can be made thinner and the optical writing unit 4-1 can be made smaller than when the shutter member 60 is made of resin. Further, by forming the airflow guide 62 by bending, the rigidity of the shutter member 60 can be increased, and the shutter member 60 and the airflow guide 62 are formed separately, and the airflow guide 62 is provided on the shutter member 60. Compared with the case of assembling, the assembly man-hours can be reduced.

  Further, as shown in the second modification, the airflow guide 62 may be formed by sticking Mylar (registered trademark), which is a resin plate, to the shutter member 60. By forming the airflow guides 62a-1 and 62a-2 with Mylar (registered trademark), the structure of the shutter member 60 can be simplified, and the shutter member 60 can be made inexpensive. Moreover, the airflow guide 62 can be formed with an inexpensive material cost, and the cost of the apparatus can be suppressed.

  Further, by providing the shutter member 60 with the cleaning member 67 that cleans the dust-proof glass while sliding on the dust-proof glass 48, it is possible to suppress the contamination of the dust-proof glass 48 such as toner.

  Further, according to the image forming apparatus of the present embodiment, by providing the above-described writing unit, it is possible to obtain a good image without color misregistration.

  In addition, by providing the blower fan 70 as a blowing unit that blows outside air to the airflow guide, the outside air can be blown to the airflow guide.

4: Optical writing units 10Y, 10C, 10M, 10K: Photoconductors 48Y, 48C, 48M, 48K: Dust-proof glass 50: Polygon scanner 52a: Lower polygon mirror 52b: Upper polygon mirror 53K, 53M, 53C, 53Y: Semiconductor laser 60: Shutter member 62: Airflow guides 63Y, 63C, 63M, 63K: Passing hole 64: Opening holes 66Y, 66C, 66M, 66K: Shielding plates 67Y, 67C, 67M, 67K: Cleaning member 70: Blower fan 71: Wall portion 72: Introduction hole 105: Deflector cover 106: Optical cover 107: Upper cover 131: Optical housing

JP 2007-148276 A

Claims (11)

In an optical scanning device that scans a surface to be scanned by deflecting and scanning light emitted from a light source by an output window of an optical housing that houses the light source and the rotary deflector.
A shutter member that is arranged opposite to the window forming surface on which the exit window of the optical housing is formed, moves parallel to the window forming surface, and shields and opens the exit window;
An optical scanning device comprising an airflow guide for allowing air to flow between the shutter member and the window forming surface. The optical scanning device according to claim 1.
The optical scanning device includes a plurality of the light sources, passes through the rotational center of the rotary deflector, and at least a pair arranged symmetrically with respect to a symmetry line drawn in a direction orthogonal to the axial direction of the rotational axis of the rotary deflector. The light emitted from at least one of the plurality of light sources is incident on one of the optical elements by the rotary deflector, exits from one of the exit windows, and another light source. The light emitted from the light beam is incident on the other optical element by the rotary deflector and emitted from the other emission window.
The shutter member is provided from the one emission window to the other emission window, and shields and opens these emission windows. The optical scanning device according to claim 2.
The shutter member has an opening hole that opens a portion of the window forming surface of the optical housing that faces the rotating deflector, and the airflow guide is provided at an end of the opening hole. apparatus. The optical scanning device according to claim 3.
An optical scanning device characterized in that a wall for allowing air to flow into the airflow guide is provided on the shutter member. In the optical scanning device in any one of Claims 1 thru | or 4,
An optical scanning device, wherein the shutter member and the airflow guide are integrally formed of resin. In the optical scanning device in any one of Claims 1 thru | or 4,
The optical scanning device, wherein the shutter member is made of sheet metal and the airflow guide is formed by bending. In the optical scanning device in any one of Claims 1 thru | or 4,
The optical scanning device according to claim 1, wherein the airflow guide is formed by attaching a resin plate to a shutter member. In the optical scanning device in any one of Claims 1 thru | or 7,
An optical scanning device, wherein the shutter member is provided with a cleaning member that cleans the exit window while sliding on the exit window. Multiple light sources;
A rotating deflector that deflects and scans light emitted from a plurality of light sources in the main scanning direction;
Including at least a pair of optical elements and an emission window arranged symmetrically with respect to a symmetry line drawn in a direction perpendicular to the axial direction of the rotation axis of the rotary deflector, passing through the rotation center of the rotary deflector,
Light emitted from at least one of the plurality of light sources is incident on one optical element by the rotary deflector and exits from one exit window, and light emitted from another light source is transmitted by the rotary deflector. In the optical scanning device of the opposed scanning system that enters the other optical element and exits from one exit window,
The optical housing housing the pair of optical elements, the rotary deflector, and the light source is disposed to face a window forming surface on which a plurality of exit windows are formed, and moves parallel to the window forming surface, A shutter member for shielding and opening the plurality of exit windows;
An optical scanning device characterized in that an opening hole for opening a portion of the window forming surface of the optical housing facing the rotary deflector is provided in the shutter member. In an image forming apparatus including an optical writing unit for writing a latent image on the surface of the latent image carrier,
An image forming apparatus using the optical scanning device according to claim 1 as the optical writing unit. The image forming apparatus according to claim 10.
An image forming apparatus comprising a blowing unit for blowing outside air to the airflow guide.

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