JP2011203586A - Optical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem with a conventional optical device, wherein an angle of a reflecting mirror is not adjusted to a desired angle because the reflecting mirror may be moved, due to friction force, in a vertical direction being not a direction in which the reflecting mirror should be displaced in accordance with movement of an adjusting screw, and a relative position between the reflecting mirror and a holding part is changed when the reflecting mirror is moved in the vertical direction during adjustment and then is moved to a stable position again.SOLUTION: The adjusting screw 308 is screwed with an adjustment base 307, and is brought into contact with a supporting member 303 in adjusting the position screwed to the adjustment base 307, thereby causing a force to act on a reflecting mirror 212 from the adjusting screw 308 via the supporting member 303.

Description

  The present invention relates to a reflection mirror position adjusting mechanism in an optical apparatus used in an image forming apparatus such as an electrophotographic copying machine or a printer.

  Scanning optical devices used in electrophotographic copying machines, printers, and the like are photosensitive drum surfaces by deflecting and scanning a light beam (laser light) from a light source (for example, a semiconductor laser) by a deflection scanning device such as a rotary polygon mirror. The top is scanned. The laser beam deflected and scanned by the rotating polygon mirror is imaged by the optical lens, reflected by the reflecting mirror, and guided to the photosensitive drum. For this reason, the laser beam toward the photosensitive drum surface is displaced from the desired optical path due to variations in positioning accuracy when mounting the optical lens and molding accuracy of the optical box, and as a result, the irradiation position of the laser beam on the photosensitive drum is shifted from the desired position. It may shift.

  To solve such a problem, the optical path of the laser beam is adjusted by adjusting the position (angle) of the reflection mirror when the scanning optical device is assembled or when the image forming apparatus is assembled, and thereby the laser beam on the photosensitive drum is adjusted. An apparatus having a configuration for performing irradiation position adjustment is disclosed (see Patent Document 1). The reflection mirror in the scanning optical device described in Patent Document 1 is pressed against the casing by a leaf spring, and thereby the reflection mirror is positioned with respect to the casing. The head of an adjustment screw screwed into the housing is in direct contact with the reflection mirror. The angle of the reflection mirror is changed by adjusting the screwing amount (screwing position) of the adjusting screw to the housing.

Japanese Patent Application Laid-Open No. 10-077854

  However, in the adjustment mechanism shown in Patent Document 1, the adjustment screw is in direct contact with the reflection mirror, and the moving direction of the adjustment screw is different from the adjustment displacement direction of the reflection mirror. For this reason, there is a possibility that the reflecting mirror moves in the vertical direction (direction of arrow A in FIG. 6A) that is not the direction to be displaced following the movement of the adjusting screw due to the frictional force. When the reflection mirror moves in the vertical direction during adjustment (FIG. 6B) and then moves again to the stable position (FIG. 6C), the angle of the reflection mirror is not adjusted to a desired angle. Since the adjustment accuracy of the reflection mirror is required to be about 0.01 degree, the positioning accuracy of the reflection mirror greatly affects the image quality. Therefore, when such a phenomenon occurs, the position of the reflecting mirror must be readjusted.

  According to the present invention, when the adjustment screw is moved to adjust the position (angle adjustment) of the reflection mirror, the movement of the adjustment screw is adjusted by using a configuration in which no frictional force is generated between the adjustment screw and the reflection mirror. An object of the present invention is to provide an optical device including an adjustment mechanism that suppresses the movement of the reflection mirror.

  The optical device according to the present invention is an optical device having a reflection mirror that guides the light beam to an irradiated object by reflecting the light beam emitted from a light source, and a housing that houses the reflection mirror. An adjustment mechanism that adjusts the installation angle of the reflection mirror through the support member, and an adjustment mechanism that adjusts the installation angle of the reflection mirror in the housing. It is characterized by having.

  According to the optical device of the present invention, since the frictional force generated between the adjusting screw and the reflecting mirror does not occur when adjusting the installation angle of the reflecting mirror, the movement of the reflecting mirror along the movement of the adjusting screw can be suppressed. .

1 is a cross-sectional view of an image forming apparatus according to Embodiment 1. FIG. FIG. 2 is a top view and a cross-sectional view of a scanning optical device according to Example 1. FIG. 3 is a diagram illustrating a position adjustment mechanism provided in the scanning optical device according to the first embodiment. FIG. 3 is a cross-sectional view of a part of the position adjustment mechanism and the scanning optical device provided in the scanning optical device according to the first embodiment. The figure which shows the other example of a position adjustment mechanism. The figure which shows the conventional position adjustment mechanism.

Example 1
The image forming apparatus according to the present embodiment will be described below with reference to FIG. FIG. 1A is a cross-sectional view of the image forming apparatus 100 according to the present embodiment. The image forming apparatus 100 includes four image forming units 101Y, 101M, 101C, and 101Bk that form toner images for each color of yellow, magenta, cyan, and black. These four image forming units 101Y, 101M, 101C, and 101Bk are an image forming unit 101Y that forms a yellow toner image along the rotation direction of an intermediate transfer belt, which will be described later, and an image forming unit 101M that forms a magenta toner image. The image forming unit 101C for forming a cyan toner image and the image forming unit 101Bk for forming a black toner image are arranged in this order. A scanning optical device 105 is provided below the four image forming units.

  FIG. 1B is an enlarged view of each image forming unit. The image forming units 101Y, 101M, 101C, and 101Bk include photosensitive drums 102Y, 102M, 102C, and 102Bk (irradiated bodies) that are photosensitive members, and a charging device that charges the photosensitive drums to a uniform background portion potential. 103Y, 103M, 103C, 103Bk. Further, the image forming units 101Y, 101M, 101C, and 101Bk include developing devices 104Y, 104M, 104C, and 104Bk that develop an electrostatic latent image formed on each photosensitive drum by a scanning optical device 105, which will be described later, with toner. Yes.

  1A, an image forming apparatus 100 according to the present exemplary embodiment includes an intermediate transfer belt 106 (Intermediate Transfer Belt) on which a toner image is primarily transferred from the photosensitive drums 102Y, 102M, 102C, and 102Bk of each image forming unit. Prepare. The intermediate transfer belt 106 is formed in an endless manner and stretched between a pair of belt conveying rollers 107 and 108, and rotates in the direction of the arrow in FIG. A toner image formed on each photosensitive drum is primarily transferred to the intermediate transfer belt 106. Primary transfer rollers 109Y, 109M, 109C, and 109Bk are disposed at positions facing the photosensitive drums of the image forming units so as to sandwich the intermediate transfer belt 106, respectively. By applying a predetermined transfer bias voltage to these primary transfer rollers 109Y, 109M, 109C, 109Bk, an electric field is formed between each photosensitive drum and the primary transfer rollers 109Y, 109M, 109C, 109Bk. The charged toner on each photosensitive drum is transferred to the intermediate transfer belt 106 by Coulomb force.

  The toner image that has been multiple-transferred to the intermediate transfer belt 106 is secondarily transferred to the recording sheet P (recording medium P) at the secondary transfer portion. At the secondary transfer position, a secondary transfer roller 110 is disposed at a position facing one of the belt conveying rollers 108, and the recording sheet P is between the secondary transfer roller 110 and the intermediate transfer belt 106 that are pressed against each other. The toner image is transferred from the intermediate transfer belt 106.

  On the other hand, the recording sheet P is fed from the paper feed cassette 111 stored in the lower part of the housing of the image forming apparatus 100 to the inside of the image forming apparatus 100, specifically, the secondary transfer roller 106 and the secondary transfer roller 110 are in contact with each other. Supplied to the transfer position.

  After receiving the transfer of the toner image at the secondary transfer position, the recording sheet P is sent to the fixing device 112 provided immediately above the secondary transfer position. Then, the toner image on the recording sheet P is heated and fixed by the fixing device 112, and then the recording sheet P is discharged through a discharge roller 113 to a discharge tray 114 provided at the upper part of the casing of the image forming apparatus 100. .

  Next, the scanning optical device 105 (scanner unit) shown in FIG. 1A will be described with reference to FIG. Below the image forming units 101Y, 101M, 101C, and 101Bk, a scanning optical device 105 that exposes the photosensitive drum in order to form an electrostatic latent image corresponding to image information on the photosensitive drum is disposed. . The scanning optical device 105 forms electrostatic latent images on the photosensitive drums provided in all the image forming units 101Y, 101M, 101C, and 101Bk.

  FIG. 2A is a top view showing the internal configuration of the scanning optical apparatus. The light source 201 includes a semiconductor laser for exposing the photosensitive drum 102Y and a semiconductor laser for exposing the photosensitive drum 102M. The light source 202 includes a semiconductor laser for exposing the photosensitive drum 102C and a semiconductor laser for exposing the photosensitive drum 102Bk. The light source is housed in the optical box 200 together with four collimator lenses (not shown) that convert the laser beam into parallel light. Corresponding to each light source, there are provided compound cylindrical lenses (204, 205) for condensing a laser beam into a long line in the main scanning direction on a polygon mirror (rotating polygonal mirror) 203 as a deflection scanning device. ing.

  The polygon mirror 203 is rotationally driven by a brushless motor (not shown), scans the black Bk laser beam and the cyan C laser beam on the right side in FIG. 2A, and sets magenta M and yellow Y on the left side of the deflector. Scan on the left side respectively.

  FIG. 2B is a sectional view of the scanning optical device 105 according to the present embodiment. Laser light deflected and scanned by the polygon mirror 203 is provided with magenta M and yellow Y optical systems independently for the black K provided on the right side of the polygon mirror 203 and on the left side of the cyan C deflector. The laser beam deflected and scanned by the detector is condensed at a predetermined position on the photosensitive drum of each color. The scanning optical system includes a first imaging lens (206, 207), a second imaging lens (208, 209, 210, 211), and reflection mirrors (212 to 219). The first imaging lens 206 is a common imaging lens for yellow laser light and magenta laser light, and the first imaging lens 207 is cyan laser light and black laser light. Is a common imaging lens. The second imaging lens is individually provided for each laser beam as shown in FIG. The first imaging lens and the second imaging lens correct Fθ of the scanning light, but the imaging in the sub-scanning direction is mainly performed by the second imaging lens.

  The laser beam for yellow and the laser beam for black are respectively guided onto the respective photosensitive drums by one reflecting mirror (a reflecting mirror 212 for yellow and a reflecting mirror 219 for black). The magenta laser light and the cyan laser light are respectively guided to the respective photosensitive drums by three reflecting mirrors (magenta reflecting mirrors 213, 214, and 215, and cyan reflecting mirrors 216, 217, and 218).

  Next, the path of a laser beam (light beam) when forming an electrostatic latent image on the photosensitive drum 102M of the magenta image forming unit 101M will be described. The description of the path of the laser beam to the photosensitive drum of the other image forming units is omitted because the characteristics of the imaging lens that passes through only the optical path is the same. The laser light emitted from the light source based on the magenta image signal modulated according to the image information is deflected and scanned by the polygon mirror 203 that is driven to rotate. The laser beam that has been deflected and scanned passes through the first imaging lens 206 and is reflected by the reflection mirrors 213, 214, and 215. The laser light passes through the second imaging lens 209 between the reflection mirror 214 and the reflection mirror 215. The laser light is reflected by the reflecting mirror 206 toward the transparent plate 212, and then passes through the transparent plate 212M and reaches the photosensitive drum 102M.

  The scanning optical apparatus according to the present embodiment has been described by taking a scanning optical apparatus provided in a color image forming apparatus having four photosensitive drums as an example. However, in the embodiment, the scanning optical apparatus is provided in a monochrome image forming apparatus. It may be a device. Further, the scanning optical apparatus according to the present embodiment has been described by taking an example of the scanning optical apparatus of the opposed scanning system that is provided in the color image forming apparatus and deflects the laser beam bidirectionally with the polygon mirror interposed therebetween and guides it to the photosensitive drum. However, the embodiment may be a scanning optical device provided for each of the four photosensitive drums.

  Next, the reflection mirror position adjustment mechanism (installation angle adjustment mechanism) that is a feature of the scanning optical apparatus according to the present embodiment will be described in detail. When assembling the above scanning optical device, the installation position (installation angle) inside the housing is adjusted for the reflection mirrors (212, 215, 218, 219) that finally reflect the laser light directed to the respective photosensitive drums. To do. By adjusting the installation position, the angle of the reflection mirror with respect to the reference surface (non-moving surface) of the scanning optical apparatus or the image forming apparatus is changed, so that the angle of the reflection mirror with respect to the incident laser light is adjusted. By performing this adjustment, the optical path of the reflected light can be adjusted, and the imaging position of the laser beam in the sub-scanning direction (rotating direction of the photosensitive drum) on the photosensitive drum can be adjusted. After adjusting the reflection mirror, a dust-proof lid 220 is attached to the optical box, and the optical box is attached to the image forming apparatus.

  FIG. 3A is a schematic explanatory view in which only the reflection mirror 212 and its supporting structure and position adjustment mechanism are extracted from the scanning optical device 105. Since this structure is similarly provided for the four reflection mirrors 212, 215, 218, and 219, the description will be given only for the reflection mirror 212. An arrow B direction shown in FIG. 3A is a direction in which the laser beam is scanned (main scanning direction), and is hereinafter referred to as a longitudinal direction of the reflection mirror 212.

  As shown in FIG. 3A, the reflection mirror 212 is positioned on one end side in the longitudinal direction by a position adjusting mechanism 300 and a spring member 304 described later, and the other end side is a projection 305 provided on the optical box 200. And the spring member 306.

  The position adjustment mechanism 300 in this embodiment is provided on the spring member 304 side. The position adjustment mechanism 300 mainly includes an adjustment table 307, an adjustment screw 308 that is an adjustment member, and a support member 303.

  FIG. 3B is a diagram in which the reflection mirror position adjusting mechanism 300 provided in the scanning optical apparatus according to the present embodiment is separated. FIG. 3C is an enlarged view of the support member 303. As shown in FIG. 3C, the support member 303 is provided with a bent portion 303c. On one side of the bent portion 303 c, a grip shape portion 303 a that grips the adjustment table 307 is provided, and the support member 303 is fixed to the adjustment table 307 according to the configuration. Further, the reflection mirror 212 is supported on the other side of the bent portion of the support member 303. Hereinafter, this portion is referred to as a support portion 303b. (See FIG. 4). The support portion 303b is formed integrally with the grip shape portion 303a so that the angle formed between the support portion 303b and the adjustment table 307 becomes an acute angle when the support member 303 is attached to the adjustment table 307. A part of the support portion 303b is planar, and one end side of the reflection mirror 212 is supported by the plane.

  The adjusting table 307 is fixed to the optical box 200 with an adhesive, a fixing screw, or the like. The adjustment base 307 is provided with a hole 310 provided with a screw thread, and the adjustment screw 308 is screwed there.

  A hemispherical tip 309 is provided at the tip of the adjustment screw 308, and the tip 309 is in contact with the support portion 303 b of the support member 303. The position of the reflection mirror 212 is adjusted (angle adjustment) by rotating the head of the adjustment screw with a jig driver.

  FIG. 4 is a cross-sectional view of the position adjusting mechanism 300 when viewed from the direction of arrow B shown in FIG. As shown in FIG. 4, in the longitudinal direction of the reflection mirror 212, one end of the reflection mirror 212 is supported by protrusions 401 and 402 provided on the optical box 200 and a support member 303. The reflection mirror 212 is pressed by the spring member 304 toward the protrusions 401 and 402 and the support member 303 and is positioned thereby. A space is provided between the optical box 200 (housing) and the reflection mirror 212 by being supported by the protrusion 401 and the protrusion 402. By providing this space, the reflection mirror 212 does not interfere with the casing when the reflection mirror 212 is rotated by the position adjustment mechanism 300.

  As shown in FIG. 4, when the adjustment screw 308 is rotated in the clockwise direction, the screwing position of the adjustment screw 308 with respect to the adjustment base 307 changes, and the adjustment screw 308 advances in the direction indicated by the black arrow. Then, the distal end portion 309 presses a part of the support portion 303b, and accordingly, the support portion 303b swings clockwise around a bent portion located in the vicinity of the adjusting table 307. The reflection mirror 212 is pressurized by the support portion 303b, and rotates in the direction of the white arrow in the figure with the protrusion 401 of the optical box 200 as a substantially rotation center.

  On the other hand, when the adjustment screw 308 is rotated counterclockwise, the adjustment screw 308 advances in the direction opposite to the direction indicated by the black arrow. Then, the tip 309 oscillates counterclockwise around the bent portion while the tip portion 309 is in contact with a part of the support portion 303b due to the elastic force of the support member 303 generated by providing the bent portion. Since the reflection mirror 212 is pressurized by the spring member 304, it follows the movement of the support portion 303b, and rotates in the direction opposite to the white arrow direction in the figure with the protrusion 401 as a substantially rotation center.

  FIG. 5 shows an adjustment plate that is a resin molding member, in which a mirror pressing portion of the adjustment plate is integrally provided on the adjustment table 400 with respect to the configuration of the adjustment plate 400 attached to the adjustment table 307 by the gripping shape portion 303a. A support portion 303 b is integrally provided with respect to 307. In this embodiment, an integrally molded product of resin material is used. However, an integrated product obtained by processing a leaf spring can have the same function. In addition, you may form the adjustment stand 307 and a housing | casing integrally.

  In this way, the force generated by the movement of the adjustment screw 308 by the support member 303 changes in a direction that changes the angle of the reflection mirror, and the force acts on the reflection mirror 212 via the support member 303, thereby causing the reflection mirror 212. Can be adjusted. Further, by providing the support member 303 between the adjustment screw 308 and the reflection mirror, the adjustment screw 308 and the reflection mirror 308 are not in direct contact with each other. No frictional force is generated between the mirror 212 and the mirror 212. Therefore, when the adjusting screw 308 is moved, the movement of the reflection mirror 212 in the direction of arrow A shown in FIG. 6 due to the frictional force is suppressed.

  Further, by employing the position adjustment mechanism 300 of this embodiment in the color image forming apparatus, it is possible to correct the laser light irradiation position on the photosensitive drum in the sub-scanning direction (rotating direction of the photosensitive drum). Accordingly, color misregistration of each color toner image transferred onto the intermediate transfer belt can be suppressed. Further, by adopting a position adjusting mechanism in the monochrome image forming apparatus, it is possible to improve the accuracy of the image forming position in the sub-scanning direction with respect to the recording paper.

212 Reflecting mirror 300 Position adjustment mechanism 303 Support member 303b Support part 307 Adjustment stand 308 Adjustment screw

Claims (5)

In an optical device having a reflection mirror that guides the light beam to an irradiated object by reflecting the light beam emitted from the light source, and a housing that houses the reflection mirror,
A support member for supporting the reflection mirror;
An adjustment member that adjusts an installation angle of the reflection mirror in the housing, and the adjustment member adjusts the installation angle of the reflection mirror via the support member;
An optical device comprising:   The adjustment mechanism includes an adjustment base to which the support member is attached and an adjustment screw that is the adjustment member. The adjustment screw abuts on the support member and adjusts a screwing position of the adjustment screw with respect to the adjustment base. The optical device according to claim 1, wherein the optical device is an adjustment mechanism that adjusts the installation angle. The support member has a bent portion, one side of the bent portion is fixed to the adjustment table, and the support member supports the reflection mirror on the other side,
The optical apparatus according to claim 2, wherein the adjustment mechanism is an adjustment mechanism that adjusts the installation angle by adjusting an angle of a bent portion of the support member.   The optical apparatus according to claim 1, wherein the casing houses the support member and the adjustment screw, and the adjustment base is provided integrally with the casing.   The optical device according to claim 4, wherein the support member is integrally provided on the adjustment table.

Images