JP2014134711A - Optical scanner and grounding structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the posture deformation of an optical scanner S attached to the body frame 46 of an image forming apparatus body.SOLUTION: In the optical scanner S which comprises a housing member 30 storing an optical member and attached to the body frame 46 of the image forming apparatus body and a metallic cover member 31 closing the housing 30 and in which the cover member 31 is grounded in such a state that the cover member 31 and the body frame 46 are electrically connected by a grounding member 50 provided to be elastically deformed between the housing member 30 and the body frame 46, the housing member 30 includes a force receiving part receiving a force by an elastic repulsive force, so that the force acts in a direction where the housing member 30 is pressed to the body frame by the elastic repulsive force generated by the elastic deformation of the grounding member 50.

Description

  The present invention relates to an optical scanning device and a grounding structure for grounding a metal cover member of a housing member of the optical scanning device.

2. Description of the Related Art Conventionally, an optical scanning device periodically deflects and scans a light beam that has been modulated from a light source according to an image signal by an optical deflector such as a rotary polygon mirror, and uses an imaging optical system having fθ characteristics to provide a photosensitive member. Focus in a spot shape on the upper image plane. An image forming apparatus provided with this optical scanning device forms an electrostatic latent image in accordance with main scanning by an optical deflector and sub-scanning by rotation of a photosensitive member, and performs image recording. In the tandem type color image forming apparatus, a number of light beams corresponding to a plurality of photosensitive members are irradiated onto the photosensitive member, and a color image is formed by superimposing the respective colors.
In recent years, there has been an increasing demand for higher definition and higher speed in color image forming apparatuses. When the polygon mirror, which is a rotating polygon mirror, is rotated at a higher speed to meet this requirement, dust entering from the outside adheres to the effective reflection surface of the polygon mirror, and the reflectivity decreases, resulting in image defects such as low image density. Arise. For this reason, the further sealing property of the housing member which accommodates an optical component (optical member) is requested | required. Further, since the operating noise is increased by rotating the polygon mirror at a high speed, the sealing performance of the housing member is also required from this viewpoint.
As the cover member for sealing the housing member, a resin molded product or a metal plate is usually used, but when a metal plate is used, a gap with the housing member due to the warpage of the cover member can be reduced compared to the resin molded product, The sealing performance of the housing member can be improved.
However, the optical scanning device includes components that handle high-frequency signals such as a laser unit and a scanner motor. If the cover member is made of metal, the cover member serves as an antenna and generates electromagnetic waves to the outside. Radiation noise becomes a problem.
Therefore, it is necessary to ground the cover member. Conventionally, one end of the grounding member is fastened to the cover member with a screw, and the other end is grounded by pressing the main body frame (Patent Document 1).
Further, as another conventional example, there has been proposed one in which the tip of a screw for fastening the cover member and the housing member is extended and the main body frame is pressed by the tip of the screw to make a ground (Patent Document 2). .

JP 2002-328326 A Japanese Patent Laid-Open No. 11-231250

However, the techniques described in Patent Documents 1 and 2 may cause the following problems.
In the configuration shown in FIG. 3 of Patent Document 1, the reaction force of the earth spring, which is a grounding member, acts in the direction of floating the optical scanning device from the main body frame to which the optical scanning device is attached. Similarly, in the configuration shown in FIG. 1 of Patent Document 2, the optical scanning device receives a force in the direction of floating from the main body frame by a screw also serving as a grounding member. When the optical scanning device receives a force in the direction of floating from the main body frame in this way, the posture of the optical scanning device changes, and as a result, color misregistration occurs.

In view of the above problems, an object of the present invention is to suppress posture deformation of an optical scanning device attached to a main body frame of an image forming apparatus main body.

In order to achieve the above object, an optical scanning device according to the present invention includes:
An optical box that houses the optical member and is attached to the main body frame of the image forming apparatus main body;
A metal lid member for closing the optical box;
Have
In the optical scanning device in which the lid member and the main body frame are electrically connected and the lid member is grounded by a grounding member that is elastically deformed between the optical box and the main body frame.
The optical box is
A force receiving portion for receiving a force by the elastic repulsive force is provided so that a force is exerted in a direction in which the optical box is pressed against the main body frame by an elastic repulsive force generated by elastic deformation of the grounding member.

The grounding structure according to the present invention is
A grounding member elastically deformed between an optical box that houses an optical member and is closed by a metal lid member, and a main body frame of an image forming apparatus main body to which the optical box is attached, A grounding member for grounding the lid member by electrically connecting the lid member and the main body frame;
The grounding member is formed such that a force acting on the optical box by an elastic repulsive force generated by elastic deformation of the grounding member acts in a direction in which the optical box is pressed against the main body frame.

  According to the present invention, it is possible to suppress the posture deformation of the optical scanning device attached to the main body frame of the image forming apparatus main body.

Schematic perspective view of the optical scanning device according to the present embodiment Schematic which shows the optical path of the light beam deflected with the deflector in a present Example. Schematic sectional view showing the optical path of the light beam incident on the deflector in the present embodiment Top side perspective view when the optical scanning device is attached to the main body frame Bottom perspective view of the optical scanning device when attached to the body frame Schematic explaining the attachment of the optical scanning device to the main body frame Top perspective view of the optical scanning device of the comparative example when attached to the main body frame Schematic diagram when mounting the optical scanning device to the body frame Schematic sectional view of the overall configuration of the image forming apparatus according to the present embodiment

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be exemplarily described in detail with reference to the drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described in this embodiment should be appropriately changed according to the configuration of the apparatus to which the invention is applied and various conditions. That is, it is not intended to limit the scope of the present invention to the following embodiments. Further, in the following description, a subscript given to a reference sign to indicate that it is an element provided for one of the colors of yellow Y, magenta M, cyan C, and black K unless particularly distinguished. In the description, Y, M, C, and K are omitted.

<Overall configuration of image forming apparatus>
First, the overall configuration of a color image forming apparatus (hereinafter referred to as an image forming apparatus) D according to the present embodiment will be described with reference to FIG. FIG. 9 is a schematic cross-sectional view of the overall configuration of the image forming apparatus according to the present embodiment. As shown in FIG. 9, the image forming apparatus D according to the present embodiment includes an optical scanning device S1, a photosensitive member 40 as an image carrier, a primary charger 43, and a developing unit 44 as a developing unit as main components. A fixing device 47 and a transfer belt 49.

  In the present embodiment, the optical scanning device S1 emits light beams LY to LK that are respectively light-modulated based on image information, and irradiates the surfaces of the corresponding photoreceptors 40Y to 40K to form electrostatic latent images. Form. At this time, the surfaces of the photoconductors 40Y to 40K are charged by the primary charger 43, respectively.

  The electrostatic latent images formed on the surfaces of the photoreceptors 40Y to 40K are visualized as toner images as developer images of yellow Y, magenta M, cyan C, and black K, respectively, by developing units 44Y to 44K. The On the other hand, the recording material P placed on the paper feed tray is fed by the feed roller 45 and conveyed to the nip portion between the transfer belt 49 and the photoreceptor 40. The visualized toner images of yellow Y, magenta M, cyan C, and black K are sequentially transferred onto the recording material P at each nip to form a color image.

  The drive roller 41 accurately feeds the transfer belt 49 and is connected to a drive motor (not shown) with little rotation unevenness. The color image formed on the recording material P is thermally fixed by the fixing device 47 and then discharged outside the device by the discharge roller 48 and the like.

<Optical scanning device>
Next, the optical scanning device S1 according to the present embodiment will be described with reference to FIGS. FIG. 1 is a schematic perspective view of the optical scanning device according to the present embodiment. FIG. 2 is a schematic diagram showing an optical path of a light beam deflected by a deflector in this embodiment. FIG. 3 is a schematic cross-sectional view showing the path of the light beam incident on the deflector in the present embodiment.

  As shown in FIG. 3, the optical scanning device S1 includes semiconductor lasers 11Y to 11K as a plurality of light sources, light source holding members 13Y to 13K that hold the light sources, and a deflector 20 that deflects and scans the light beams emitted from the light sources. Have. As shown in FIG. 2, the optical scanning device S <b> 1 is arranged on both sides so as to sandwich the deflector 20 with the rotation axis 20 a of the deflector 20 being symmetrical, and the light beam L deflected by the deflector 20 Each has a plurality of optical scanning systems for scanning (light guiding) on separate photoconductors 40Y to 40K. As shown in FIG. 2, the optical scanning system includes scanning lenses 23, 24, 25Y, 25M, 25C, and 25K, and folding mirrors 26Y1 to 26K1, 26M2, and the like. 26C2.

  Further, as shown in FIG. 1, the optical scanning device S1 includes a housing member 30 as an optical box that accommodates optical members such as the light source holding members 13Y to 13K, the deflector 20, and the plurality of optical scanning systems. . In this embodiment, a resin material such as PC (polycarbonate) -ABS (acrylonitrile / butadiene / styrene copolymer) is used as the material of the housing member 30.

  Further, details of the optical scanning device S1 according to the present embodiment will be described. The optical scanning device S1 according to the present embodiment is a unit mounted on the tandem color image forming apparatus main body. The optical scanning device S1 performs optical scanning on the photoreceptors 40Y, 40M, 40C, and 40K corresponding to the colors of yellow Y, magenta M, cyan C, and black K. In the following description, for convenience, the optical scanning system corresponding to each color will be referred to as Y station, M station, C station, and K station.

The optical scanning device S1 includes light source units 10Y to 10K, a deflector 20, and a housing member 30.
have. In FIG. 2, the optical scanning device S <b> 1 has a first optical scanning system on the left side and a second optical scanning system on the right side with respect to the rotation shaft 20 a of the deflector 20. 1 and 3, the light source units 10Y to 10K include semiconductor lasers 11Y to 11K as light sources, collimator lenses 12Y to 12K, and light source holding members 13Y to 13K.

  The semiconductor lasers 11Y to 11K are four light sources that are independently controlled to emit light according to image information. The semiconductor laser 11M constitutes a first light source, and the semiconductor laser 11C constitutes a second light source. The collimator lenses 12Y to 12K correspond to the respective semiconductor lasers 11Y to 11K. The light source holding members 13Y to 13K hold the semiconductor lasers 11Y to 11K and the lenses 12Y to 12K with high accuracy. As shown in FIG. 3, the deflector 20 includes a rotary polygon mirror 21 that reflects the light beams emitted from the semiconductor lasers 11 </ b> Y to 11 </ b> K to the scanning lens side, and a motor unit 21 b that rotates the rotary polygon mirror 21. . A rotating shaft 20 a of the deflector 20 is a rotating shaft of the rotary polygon mirror 21.

  The first optical scanning system and the second optical scanning system include first scanning lenses 23 and 24, second scanning lenses 25Y to 25K, folding mirrors 26Y1 to 26K1, 26M2, and 26C2, and a cylindrical lens 27. The first optical scanning system (Y station, M station) and the second optical scanning system (C station, K station) respectively scan two independent light beams. The housing member 30 is configured to accommodate the deflector 20, the scanning lenses 23, 24, 25Y to 25K, and the folding mirrors 26Y1 to 26K1, 26M2, and 26C2.

  In the Y station, the light beam LY emitted from the semiconductor laser 11Y is substantially collimated by the lens 12Y, passes through the cylindrical lens 27, and is deflected by the deflector 20. The deflected light beam LY passes through the first scanning lens 23 and the second scanning lens 25Y, is reflected (folded back) by the folding mirror 26Y1 of the plane mirror, and passes through the emission port provided on the bottom surface of the housing member 30. Then, it is guided to the photoreceptor 40Y and draws a scanning line.

  In the M station, the light beam LM emitted from the semiconductor laser 11M is made into substantially parallel light by the lens 12M, passes through the lens 27, and is deflected by the deflector 20. The deflected light beam LM passes through the first scanning lens 23, is changed in direction by the folding mirror 26M1, passes through the second scanning lens 25M, is reflected by the folding mirror 26M2, and is provided on the bottom surface of the housing member 30. Pass through the exit. In this way, the light beam LM is guided to the photoreceptor 40M and draws a scanning line.

  The first optical scanning system and the second optical scanning system have different light fluxes on different sides with respect to the rotating shaft 20a of the deflector 20, that is, on the left and right sides with respect to the rotating shaft 20a of the deflector 20, as shown in FIG. Is a so-called face-to-face scanning system in which scanning is deflected. Here, in FIG. 2, the left and right sides with respect to the rotation axis 20a of the deflector 20 are the left and right sides with respect to the rotation axis 20a of the rotary polygon mirror 21 when the deflector 20 is viewed from the semiconductor lasers 11Y to 11K. That means. Therefore, the C station has a configuration similar to the M station, and the K station has a configuration similar to the Y station.

Here, the light beam LM emitted from the semiconductor laser 11M forms a first light beam, and the light beam LC emitted from the semiconductor laser 11C forms a second light beam. Further, the folding mirror 26M1 constitutes a first folding mirror that folds the light beam LM so as to approach the deflector 20 in the optical axis direction of the light beam LM deflected and scanned by the deflector 20. The folding mirror 26M2 constitutes a second folding mirror that folds the light beam LM folded by the folding mirror 26M1 toward the photoconductor 40M. The folding mirror 26C1 constitutes a third folding mirror that folds the light beam LC so as to approach the deflector 20 in the optical axis direction of the light beam LC deflected and scanned by the deflector 20. The folding mirror 26C2 constitutes a fourth folding mirror that folds the light beam LC folded by the folding mirror 26C1 toward the photoconductor 40C.

Example 1
Next, the attachment of the optical scanning device S1 according to the first embodiment to the main body frame 46 will be described with reference to FIGS. FIG. 4 is a top side perspective view of the optical scanning device according to the first embodiment when attached to the main body frame. FIG. 5 is a bottom perspective view of the optical scanning apparatus according to the first embodiment when attached to the main body frame.

  As shown in FIG. 4, the main body frame 46 of the image forming apparatus D is provided so as to be opposed, and the optical scanning device S <b> 1 is assembled between the opposed main body frames 46. Further, as shown in FIG. 4, the optical scanning device S <b> 1 has mounting portions 30 a and 30 b provided at one of both ends of the bottom surface of the housing member 30 in the photoconductor arrangement direction, and a mounting portion 30 c provided at the other. doing. The housing member 30 is covered and closed by a cover member 31 as a metal lid member provided to face the bottom surface.

  In the optical scanning device S1, the attachment portions 30a to 30c are urged in the direction of arrow A in FIG. 4 by an unillustrated elastic member, so that the three attachment surfaces 30a1, 30b1, and 30c1 shown in FIG. In contact with the image forming apparatus D. The reason for using the elastic member is to suppress deformation of the housing member 30 that occurs when the optical scanning device S1 is fixed to the main body frame 46. In the case of fastening with screws, when the screw header portion contacts the housing member 30, the rotational torque of the screws is transmitted to the housing member 30, and the housing member 30 is deformed by the rotational torque, and the position of the optical component is accordingly displaced. There is a risk that. As a result, the irradiation position of the light beams of the respective colors adjusted with high accuracy onto the photosensitive member is shifted, and color shift occurs.

  In addition, as shown in FIG. 5, the positioning bosses 32 and 33 of the housing member 30 are fitted into the holes 46a and the long holes 46b provided in the main body frame 46, respectively. It is done by doing.

<Example 1: Grounding structure>
Next, the grounding structure of the cover member 31 using the grounding member 50, which is a characteristic part of the first embodiment, will be described with reference to FIG. FIG. 6 is a schematic diagram illustrating attachment of the optical scanning device according to the first embodiment to the main body frame. FIG. 6A is a schematic diagram before the optical scanning device is attached to the main body frame, and FIG. 6B is a schematic diagram in a state where the optical scanning device is attached to the main body frame.

  As shown in FIG. 6 (a), the grounding member 50 is a leaf spring having a substantially U shape composed of a straight portion 50a and a bending portion 50b, and has a grounding portion 50c that presses the main body frame 46. ing. The grounding member 50 is a thin plate-like metal elastic member having a spring property. On the other hand, on the outer wall side surface of the housing member 30, as shown in FIG. 6A, an inclined surface as a force receiving portion (force receiving surface) that is inclined so as to approach the housing member 30 as the distance from the mounting surfaces 30 a 1 and 30 b 1 increases. A member having 34 is provided. In other words, the inclined surface 34 is inclined with respect to the direction in which the elastic repulsion force by the grounding member 50 acts.

As shown in FIG. 6B, the ground member 50 is provided between the main body frame 46 and the housing member 30 by being elastically compressed (elastically deformed). Then, the grounding member 50 is fixed to the housing member 30 by fastening one end extended from the straight portion 50 a to the cover member 31 with the screw 35 in a state where the straight portion 50 a is in contact with the inclined surface 34.

  In a state where the optical scanning device S1 is attached to the main body frame 46, the grounding portion 50c presses the main body frame 46 with a predetermined pressure by an elastic repulsive force generated by the bending portion 50b of the grounding member 50 being bent. Become. By attaching the grounding member 50 in this manner, the cover member 31 is grounded by electrically connecting the metal cover member 31 and the main body frame 46.

  Here, as shown in FIG. 6B, the optical scanning device S1 (housing member 30) receives the elastic repulsion force of the grounding member 50 when the optical scanning device S1 is attached to the main body frame. Since the slope 34 receives the elastic repulsive force from the straight portion 50a, the direction of the elastic repulsive force that the optical scanning device S1 receives from the grounding member 50 is the direction of arrow B in FIG. That is, the optical scanning device S1 is urged (pressed) in the direction pressed against the main body frame 46 and in the direction perpendicular thereto. In this manner, the optical scanning device S1 receives a force biased (pressed) from the grounding member 50, and therefore does not leave the main body frame 46. Therefore, since the mounting posture of the optical scanning device S1 with respect to the main body frame 46 does not change, and the irradiation position of each color does not change, the occurrence of color misregistration can be suppressed.

  Further, as described above, the optical scanning device S1 is urged in a direction perpendicular to the direction in which the optical scanning device S1 is pressed against the main body frame 46 (a direction parallel to the mounting surfaces 30a1 to 30c1) by the elastic repulsive force. When such an acting force is applied, for example, as shown in FIG. 7, when the mounting position of the grounding member 50 is outside the positioning bosses 32, 33, the optical scanning device S <b> 1 has the positioning boss 32. Will receive a force rotating in the direction of arrow C about the rotation axis 32a. In positioning, since the fitting play is provided to some extent due to its attachment property, the optical scanning device S1 is rotated in a state in which the attachment surfaces 30a1, 30b1, 30c1 are in contact with the frame 46 because of the fitting play. As a result, the irradiation position also changes and color misregistration occurs. However, in this embodiment, as shown in FIG. 4, the mounting position of the grounding member 50 is between both positioning bosses 32 and 33. For this reason, since no rotational force is generated around one of the positioning bosses, the optical scanning device S1 does not rotate by the amount of fitting backlash, and the fitting backlash can always be moved in the same direction.

  As described above, in the first embodiment, the optical scanning device S1 causes the elastic repulsive force of the grounding member 50 to act in the direction of the mounting plane 36 of the main body frame 46, thereby suppressing the posture deformation of the optical scanning device S1. be able to. As a result, color misregistration can be reduced.

  Furthermore, by providing the grounding member 50 between the positioning bosses 32 and 33, it is possible to suppress the posture deformation caused by the rotation of the optical scanning device S1 due to the fitting backlash. As a result, color misregistration can be reduced.

(Example 2)
Next, Example 2 in which the grounding member has another shape will be described with reference to FIG. FIG. 8 is a schematic diagram when the optical scanning device according to the second embodiment is attached to the main body frame. In addition, the same code | symbol is attached | subjected about the component similar to Example 1 mentioned above, and the description is abbreviate | omitted. As shown in FIG. 8, in the second embodiment, the grounding member 60 is fastened to the main body frame 46 with screws 35. The ground member 60 is attached by being elastically deformed.

In the second embodiment, as shown in FIG. 8, the cover member 31 has a bent portion 31 a as a force receiving surface that receives the elastic repulsive force of the grounding member 60. The elastically deformed grounding member 60 presses the bent portion 31a in the direction of arrow D in FIG. 8 by the grounding portion 60c.
Therefore, the optical box 30 receives a force due to the elastic repulsive force of the grounding member 60 via the bent portion 31 a of the cover member 31. With such a configuration, the same effect as in the first embodiment can be obtained. In addition, the problem of deformation of the grounding member during handling of the optical scanning device S1, which is a concern when the grounding member is fastened to the cover member 31 of the housing member 30 in the configuration of the first embodiment, can be prevented. .

  DESCRIPTION OF SYMBOLS 30 ... Housing member, 31 ... Cover member, 46 ... Main body frame, 50 ... Grounding member, S1 ... Optical scanning device

Claims (8)

An optical box that houses the optical member and is attached to the main body frame of the image forming apparatus main body;
A metal lid member for closing the optical box;
Have
In the optical scanning device in which the lid member and the main body frame are electrically connected and the lid member is grounded by a grounding member that is elastically deformed between the optical box and the main body frame.
The optical box is
An optical scanning having a force receiving portion that receives a force of the elastic repulsive force so that a force acts in a direction in which the optical box is pressed against the main body frame by an elastic repulsive force generated by elastic deformation of the grounding member. apparatus.   The optical scanning device according to claim 1, wherein the force receiving portion is a force receiving surface that receives the elastic repulsion force formed on a side surface of the outer wall of the optical box.   The optical scanning device according to claim 1, wherein the force receiving portion receives a force due to the elastic repulsive force through a force receiving surface that receives the elastic repulsive force formed on the lid member.   The optical force according to claim 2 or 3, wherein the force receiving surface is inclined with respect to a direction in which the elastic repulsive force acts so that a force acts in the pressing direction by the elastic repulsive force. Scanning device. The optical box and the main body frame are positioned in a plurality of positioning portions,
5. The optical scanning device according to claim 1, wherein the force receiving portion is formed between any two positioning portions of the plurality of positioning portions. 6. The optical member is
At least a light source, a light source holding member that holds the light source, a deflecting unit that deflects a light beam emitted from the light source, a scanning lens and a folding mirror that introduces the light beam deflected by the deflecting unit into the image carrier, The optical scanning device according to claim 1, wherein the optical scanning device is configured as follows. A grounding member elastically deformed between an optical box that houses an optical member and is closed by a metal lid member, and a main body frame of an image forming apparatus main body to which the optical box is attached, A grounding member for grounding the lid member by electrically connecting the lid member and the main body frame;
The grounding member is formed so that a force acting on the optical box by an elastic repulsive force generated by elastic deformation of the grounding member acts in a direction of pressing the optical box against the main body frame. Construction. The grounding member is
The grounding structure according to claim 7, wherein the grounding structure is a substantially U-shaped leaf spring that is elastically compressed between the optical box and the main body frame.

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