JP2010191045A - Optical scanner and image forming apparatus equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical scanner in which the shift of a light beam radiation position is corrected on a face to be scanned corresponding to the accuracy and error of the manufacturing and assembling of a housing, a lens and a mirror or the like. <P>SOLUTION: The optical scanner 20 includes: a light source 22 which radiates a light beam; an optical deflector 40 which deflects the light beam radiated from the light source 22 in a main scanning direction; and an optical path adjustment mirror 61 on the optical path at the upstream side of the light advancing direction of the optical deflector 40 with which the position of the reflection point and the angle of reflection of the light beam arriving at the optical deflector 40 with respect to the reflection face of the optical deflector are adjustable. Thus, a position in the main scanning direction and a scanning line pitch in the sub-scanning direction of the light beam arriving at the polygon mirror 41 of the optical deflector 40 are accurately adjustable. Furthermore, since such adjustment is performed at one position, a time and labor necessary for adjusting installation angles of a plurality of other mirrors and lenses are reduced. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical scanning device that is mounted on an image forming apparatus such as a copying machine, a printer, or a facsimile machine, and exposes and scans the surface of an image carrier with a light beam (for example, laser light). The present invention also relates to an image forming apparatus equipped with this optical scanning device.

  An optical scanning device mounted on an image forming apparatus such as a copying machine, a printer, or a facsimile is generally exposed while scanning the surface of an image carrier represented by a photosensitive drum, that is, a scanned surface. A predetermined electrostatic latent image is formed on the drum surface. In an optical scanning device, a light beam such as laser light emitted from a light source is deflected in a main scanning direction by an optical deflector and emitted toward a surface to be scanned by a reflecting mirror.

  Specifically, the optical scanning device generally includes a light source such as a laser diode, and laser light emitted from the light source is incident on a polygon mirror that is a rotating polygon mirror of the optical deflector. The polygon mirror reflects the laser beam on its reflecting surface and deflects it in the main scanning direction. Each laser beam deflected in the main scanning direction is subsequently deflected at a constant speed in parallel with the axial direction of the photosensitive drum by an fθ lens, and is emitted toward the surface of the photosensitive drum through a reflection mirror to form an image. The Note that in an optical scanning device that supports color printing, laser light may be irradiated onto the same reflecting surface of a polygon mirror simultaneously from a plurality of light sources.

  In such an optical scanning device, the irradiation position of the light beam on the surface to be scanned is intended due to the accuracy and error in the assembly and manufacturing of the housing, lens, and mirror of the optical scanning device body. The problem of shifting will occur. In order to solve this problem, various methods for adjusting the irradiation position of the light beam on the surface to be scanned have been proposed, and examples thereof can be seen in Patent Documents 1 and 2. The optical scanning devices described in Patent Documents 1 and 2 include a mechanism that changes the installation angle of the folding mirror and the imaging lens.

JP 2003-337294 A (page 6-7, FIG. 4, FIG. 6) JP 2007-139932 A (page 15, FIG. 7)

  The optical scanning devices described in Patent Documents 1 and 2 adjust the irradiation position of the light beam by changing the installation angle of the folding mirror and the imaging lens. However, in this configuration, since the irradiation position of the light beam after being reflected by the polygon mirror of the optical deflector is adjusted, an abnormality occurs in the optical path before reaching the polygon mirror, and the irradiation position with respect to the polygon mirror is detected. If there is a large deviation, there is a possibility that the irradiation position cannot be properly adjusted thereafter. Therefore, the deviation of the light beam irradiation position on the surface to be scanned cannot be corrected, and there is a possibility that high-quality image formation cannot be realized. In the case of an optical scanning device for color printing, there are a plurality of folding mirrors and imaging lenses corresponding to each color. Therefore, in the configurations of Patent Documents 1 and 2, the installation angles of the folding mirrors and imaging lenses are set differently. Adjustment is required, which is very inconvenient and requires a considerable amount of time for adjustment.

  On the other hand, especially in an optical scanning device that supports color printing, the position in the main scanning direction and the scanning line pitch in the sub-scanning direction of a plurality of light beams simultaneously irradiated on the same reflecting surface of the polygon mirror must be adjusted with high accuracy. I must. Furthermore, with the recent increase in printing speed, which is strictly required, the polygon mirror tends to be multi-faced and the width of the reflecting surface tends to be narrowed, and the light beam may deviate from the reflecting surface area. As a result, there is a possibility that an image defect may occur on the surface to be scanned, so that a highly accurate adjustment is required with respect to the position in the main scanning direction on the reflecting surface.

  The present invention has been made in view of the above points, and in the manufacture of the housing, lens, mirror, etc. of the optical scanning device, the position of the light beam irradiation position on the surface to be scanned corresponds to the accuracy and error in assembly. It is an object of the present invention to provide an optical scanning device that can correct a deviation and obtain a high-quality image. Another object of the present invention is to provide a high-performance image forming apparatus equipped with such an optical scanning device.

  In order to solve the above problems, the present invention provides a light source that emits a light beam, a light deflector that deflects the light beam emitted from the light source in the main scanning direction, and a light beam reflected by the light deflector. And an optical member group for guiding the light beam onto the surface to be scanned, the light beam reaching the light deflector on the optical path upstream in the light traveling direction of the light deflector with respect to the light deflector reflecting surface. An optical path adjustment mirror capable of adjusting the reflection point position and reflection angle is provided.

  In the optical scanning device having the above-described configuration, the optical path adjustment mirror can be rotated about an axis parallel to the main scanning direction of the light beam and can be rotated about an axis perpendicular to the main scanning direction of the light beam. It was supposed to be.

  In the optical scanning device having the above-described configuration, the support member that supports the optical path adjustment mirror, the biasing member that presses the optical path adjustment mirror toward the support member, and the support member against the elastic force of the biasing member. The optical path adjusting mirror is provided with a displacement member that rotates and displaces the optical path adjusting mirror about the axis that is perpendicular to the main scanning direction of the light beam in the direction away from it.

  In the optical scanning device having the above-described configuration, a support member that supports the optical path adjustment mirror, and a shaft portion that holds the support member and rotates the support member about an axis that is perpendicular to the main scanning direction of the light beam. And provided base member.

  Further, in the optical scanning device having the above-described configuration, bosses are provided at both ends of the support member in a direction parallel to the main scanning direction of the light beam, and V-shaped grooves that hold the locations of the bosses of the support member are provided. I decided to prepare.

  In the present invention, the optical scanning device is mounted on an image forming apparatus.

  According to the configuration of the present invention, the light source that irradiates the light beam, the optical deflector that deflects the light beam emitted from the light source in the main scanning direction, and the light beam reflected by the optical deflector In the optical scanning device comprising the optical member group guided upward, the reflection point position of the light beam reaching the optical deflector on the optical path on the upstream side in the light traveling direction of the optical deflector with respect to the optical deflector reflecting surface; Since the optical path adjustment mirror capable of adjusting the reflection angle is provided, the position of the light beam reaching the optical deflector in the main scanning direction and the scanning line pitch in the sub-scanning direction can be accurately adjusted. And since those adjustments can be performed at one place, it is possible to reduce the labor involved in adjusting the installation angles of a plurality of other mirrors and lenses. In addition, even when the reflection surface of the polygon mirror becomes narrow in response to the increase in speed, it is possible to perform highly accurate optical path adjustment on the reflection surface. In this way, the deviation of the light beam irradiation position on the surface to be scanned can be corrected in accordance with the accuracy and error in the fabrication and assembly of the optical scanning device housing, lens, mirror, etc. An optical scanning device capable of obtaining a quality image can be provided.

  Further, the optical path adjusting mirror can be rotated about an axis center parallel to the main scanning direction of the light beam and can be rotated about an axis center perpendicular to the main scanning direction of the light beam. With the configuration, the reflection point position and reflection angle of the light beam reaching the optical deflector with respect to the optical deflector reflection surface can be adjusted. As a result, it is possible to further reduce the trouble of adjusting the position of the light beam reaching the optical deflector in the main scanning direction and the scanning line pitch in the sub-scanning direction, and further increase the optical path adjustment corresponding to high-speed printing. It is possible to improve the accuracy. Therefore, the image quality can be improved.

  A support member that supports the optical path adjustment mirror; an urging member that presses the optical path adjustment mirror toward the support member; and an optical path adjustment mirror that emits light in a direction away from the support member against the elastic force of the urging member. Since it is provided with a displacement member that is rotationally displaced about the axis that is perpendicular to the main scanning direction of the beam, the light deflector reflection surface of the light beam that easily reaches the light deflector simply by operating the displacement member It is possible to adjust the reflection point position with respect to. Thereby, when performing highly accurate optical path adjustment corresponding to high-speed printing, the effort concerning adjustment of the position of the light beam reaching the optical deflector in the main scanning direction can be further reduced.

  A support member that supports the optical path adjusting mirror; and a base member that holds the support member and is provided with a shaft portion that rotates the support member about an axis that is perpendicular to the main scanning direction of the light beam. As a result, it is possible to easily adjust the position of the reflection point of the light beam reaching the optical deflector with respect to the optical deflector reflection surface simply by operating the base member. Thereby, when performing highly accurate optical path adjustment corresponding to high-speed printing, the effort concerning adjustment of the position of the light beam reaching the optical deflector in the main scanning direction can be further reduced.

  Further, since the boss portions are provided at both ends of the support member in the direction parallel to the main scanning direction of the light beam, and the V-shaped groove portion for holding the location of the boss portion of the support member is provided, the V-shape The optical path adjustment mirror can be easily rotated about the axis parallel to the main scanning direction of the light beam along the groove. Thereby, the reflection angle of the light beam reaching the optical deflector with respect to the optical deflector reflection surface can be adjusted with a simpler configuration. Therefore, it is possible to further reduce the labor involved in adjusting the scanning line pitch in the sub-scanning direction of the light beam reaching the optical deflector, and it is possible to further improve the optical path adjustment.

  In the present invention, since the optical scanning device is mounted on the image forming apparatus, the surface to be scanned corresponds to the accuracy and error in assembling the housing, lens, mirror, etc. of the optical scanning device. It is possible to provide a high-performance image forming apparatus that can correct the deviation of the light beam irradiation position above and obtain a high-quality image.

1 is a schematic vertical sectional front view of an image forming apparatus equipped with an optical scanning device according to a first embodiment of the present invention. It is a model vertical cross section front view of the optical scanning device shown in FIG. FIG. 3 is a schematic top view of the optical scanning device shown in FIG. 2. FIG. 4 is a partially enlarged top view around the optical path adjustment mechanism of the optical scanning device shown in FIG. 3. FIG. 5 is a vertical sectional view taken along line VV around the optical path adjustment mechanism shown in FIG. 4. FIG. 5 is a perspective view around the optical path adjustment mechanism shown in FIG. 4. It is the perspective view seen from the front side of the optical path adjustment mirror and support member shown in FIG. It is the perspective view seen from the back side of the optical path adjustment mirror and support member shown in FIG. It is a perspective view of the pressing member shown in FIG. It is a partial enlarged top view of the periphery of the optical path adjustment mechanism of the optical scanning device according to the second embodiment of the present invention. FIG. 11 is a vertical sectional view taken along line XI-XI around the optical path adjusting mechanism shown in FIG. 10. It is the perspective view seen from the upper direction of the base member shown in FIG. It is the perspective view seen from the downward direction of the base member shown in FIG. It is a perspective view of the supporting member shown in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  First, the image output operation of the image forming apparatus equipped with the optical scanning device according to the first embodiment of the present invention will be described while explaining the outline of the structure with reference to FIG. FIG. 1 is a schematic vertical sectional front view of an image forming apparatus. This image forming apparatus is of a color printing type in which a toner image is transferred onto a sheet using an intermediate transfer belt.

  As shown in FIG. 1, a paper feed cassette 3 is disposed below the inside of the main body 2 of the image forming apparatus 1. The paper feed cassette 3 stores and accommodates paper P such as cut paper before printing. The sheets P are separated and sent one by one toward the upper left of the sheet cassette 3 in FIG. The paper feed cassette 3 can be pulled out horizontally from the front side of the main body 2.

  A first paper transport unit 4 is provided inside the main body 2 and to the left of the paper feed cassette 3. The first paper transport unit 4 is formed substantially vertically along the left side surface of the main body 2. The first paper transport unit 4 receives the paper P sent out from the paper feed cassette 3 and transports the paper P vertically upward along the left side surface of the main body 2 to the secondary transfer unit 9.

  A manual paper feed unit 5 is provided above the paper feed cassette 3 at a location on the right side which is the side opposite to the left side of the main body 2 where the first paper transport unit 4 is formed. Yes. In the manual paper feed unit 5, paper of a size that is not in the paper feed cassette 3, or paper that is to be manually fed, such as thick paper and OHP sheets, is placed.

  A second paper transport unit 6 is provided on the left side of the manual paper feed unit 5. The second paper transport unit 6 is located immediately above the paper feed cassette 3, extends substantially horizontally from the manual paper feed unit 5 to the first paper transport unit 4, and joins the first paper transport unit 4. The second paper transport unit 6 receives the paper sent out from the manual paper feed unit 5 and transports it to the first paper transport unit 4 substantially horizontally.

  On the other hand, the image forming apparatus 1 receives document image data from an external computer (not shown). The information of the image data is sent to the optical scanning device 20 that is an exposure unit disposed above the second paper transport unit 6. The laser beam L controlled based on the image data is emitted toward the image forming unit 30 by the optical scanning device 20.

  A total of four image forming units 30 are provided above the optical scanning device 20, and an intermediate transfer belt 7 using an intermediate transfer member in the form of an endless belt is provided above each image forming unit 30. The intermediate transfer belt 7 is supported by being wound around a plurality of rollers, and is rotated clockwise in FIG. 1 by a driving device (not shown).

  As shown in FIG. 1, the four image forming units 30 are of a so-called tandem type arranged in a line from the upstream side in the rotational direction to the downstream side in the rotational direction of the intermediate transfer belt 7. The four image forming units 30 are, in order from the upstream side, a yellow image forming unit 30Y, a magenta image forming unit 30M, a cyan image forming unit 30C, and a black image forming unit 30B. These image forming units 30 are replenished with a developer (toner) by a developer supply container and a conveying unit (not shown) corresponding to each color. In the following description, the identification symbols “Y”, “M”, “C”, and “B” are omitted unless particularly limited.

  In each image forming unit 30, an electrostatic latent image of a document image is formed by the laser light L emitted by the optical scanning device 20 that is an exposure unit, and a toner image is developed from the electrostatic latent image. The toner image is primarily transferred to the surface of the intermediate transfer belt 7 by the primary transfer unit 8 provided above each image forming unit 30. Then, as the intermediate transfer belt 7 rotates, the toner image of each image forming unit 30 is transferred to the intermediate transfer belt 7 at a predetermined timing, so that the surface of the intermediate transfer belt 7 has four colors of yellow, magenta, cyan, and black. A color toner image is formed by superimposing the color toner images.

  A secondary transfer unit 9 is disposed at a position where the intermediate transfer belt 7 is suspended on the sheet conveyance path. The color toner image on the surface of the intermediate transfer belt 7 is transferred to the paper P sent in synchronization by the first paper transport unit 4 at the secondary transfer nip portion formed in the secondary transfer unit 9.

  After the secondary transfer, deposits such as toner remaining on the surface of the intermediate transfer belt 7 are cleaned for the intermediate transfer belt 7 provided on the upstream side in the rotation direction of the yellow image forming portion 30Y with respect to the intermediate transfer belt 7. It is cleaned and collected by the apparatus 10.

  A fixing device 11 is provided above the secondary transfer unit 9. The sheet P carrying the unfixed toner image in the secondary transfer unit 9 is sent to the fixing device 11 where the toner image is heated and pressed by a heat roller and a pressure roller to be fixed.

  A branch portion 12 is provided above the fixing device 11. The sheet P discharged from the fixing device 11 is discharged from the branching unit 12 to the sheet discharging unit 13 provided at the upper part of the image forming apparatus 1 when double-sided printing is not performed.

  The discharge port portion from which the paper P is discharged from the branch portion 12 toward the paper discharge portion 13 functions as the switchback portion 14. When performing duplex printing, the switchback unit 14 switches the transport direction of the paper P discharged from the fixing device 11. Then, the sheet P is sent downward through the branching unit 12, the left side of the fixing device 11, and the left side of the secondary transfer unit 9, and again passes through the first sheet transport unit 4 to the secondary transfer unit 9. Sent.

  Next, an outline of the structure of the optical scanning device 20 of the image forming apparatus 1 will be described with reference to FIGS. 2 and 3. 2 is a schematic vertical sectional front view of the optical scanning device, and FIG. 3 is a schematic top view of the optical scanning device. As described above, the optical scanning device 20 is designed to be mounted on the tandem-type image forming apparatus 1 provided with four photosensitive drums corresponding to four colors of yellow, magenta, cyan, and black. It has been done.

  As shown in FIGS. 2 and 3, the optical scanning device 20 includes a light source 22, an optical deflector 40, an optical member group 50, an optical sensor 23, and an optical path adjustment mechanism 60 inside the housing 21.

  The housing 21 has a box shape with an upper surface formed as an open portion. A thin plate-like lid member (not shown) is mounted on the upper surface of the housing 21 so as to cover and close the open portion. Both the housing 21 and the lid member are made of synthetic resin.

  The light source 22 is provided on one end side of the housing 21, that is, on the right end side in FIG. The optical scanning device 20 corresponds to four colors of yellow, magenta, cyan, and black, and four independent light sources 22 are provided. The light source 22 is composed of a laser diode having a specification for irradiating a visible region light beam, for example, a laser beam of about 670 nm.

  The optical deflector 40 is provided in the vicinity of the light source 22 and on one end side of the housing 21, that is, on the right end side in FIG. The optical deflector 40 includes a polygon mirror 41 that is a rotating polygon mirror and a motor 42. The motor 42 rotates the polygon mirror 41 having a regular polygonal plane shape around the axis in the vertical direction in FIG. A plurality of reflecting surfaces for reflecting light are provided around the polygon mirror 41 that rotates about the axis.

  The laser beams LY, LM, LC, and LB emitted from the four light sources 22 are incident on the reflection surface around the polygon mirror 41 while being shifted by a minute angle in the sub-scanning direction (vertical direction in FIG. 2). . While rotating, the polygon mirror 41 reflects each laser beam on its reflecting surface and deflects it in the main scanning direction (vertical direction in FIG. 3), while at the other end in the housing 21, that is, the left in FIGS. Lead towards the direction.

  The optical member group 50 is provided in a region in the housing 21 where the laser light reflected by the optical deflector 40 travels. The optical member group 50 includes a first fθ lens 51, a second fθ lens 52, and a reflection mirror 53.

  The first fθ lens 51 is disposed at a position immediately ahead where the laser beams LY, LM, LC, and LB reflected by the optical deflector 40 travel. The first fθ lens 51 is shared by the laser beams LY, LM, LC, and LB, and one first fθ lens 51 is provided. In the first fθ lens 51, the laser beams LY, LM, LC, and LB are deflected at a constant speed in the main scanning direction. Furthermore, the first fθ lens 51 corrects the adverse effects on the scanning such as the incident angles of the laser beams LY, LM, LC, and LB to the polygon mirror 41 and the surface tilt of the polygon mirror 41, while correcting the laser beams LY, LM, and LC. , Slightly increase the angle of LB in the sub-scanning direction.

  The yellow laser light LY that has passed through the first fθ lens 51 is reflected by the reflection mirror 53Ya in the vicinity of the inner bottom surface of the housing 21 and is folded back toward the first fθ lens 51. Thereafter, the laser beam LY passes through the second fθ lens 52Y, is reflected by the reflection mirror 53Yb near the upper end of the housing 21, and reaches the surface of the yellow photosensitive drum 31Y, which is the scanning surface, to form an image.

  The magenta laser light LM that has passed through the first fθ lens 51 is also reflected by the reflection mirror 53Ma near the inner bottom surface of the housing 21 and folded back toward the first fθ lens 51, similarly to the yellow laser light LY. Thereafter, the laser beam LM passes through the second fθ lens 52M, is reflected by the reflection mirror 53Mb near the upper end of the housing 21, reaches the surface of the magenta photosensitive drum 31M, which is the scanning surface, and forms an image.

  The cyan laser light LC that has passed through the first fθ lens 51 is reflected substantially vertically upward by the reflecting mirror 53Ca in the vicinity of the inner bottom surface of the housing 21, and then substantially in the horizontal direction by the reflecting mirror 53Cb in the vicinity of the upper end of the housing 21. Then, it is folded in the direction of the first fθ lens 51. Thereafter, the laser beam LC passes through the second fθ lens 52C, is reflected by the reflection mirror 53Cc, and reaches the surface of the cyan photosensitive drum 31C, which is the scanning surface, to form an image.

  The black laser beam LB that has passed through the first fθ lens 51 passes through the second fθ lens 52B directly without passing through the reflection mirror. Thereafter, the laser beam LB is reflected by the reflection mirror 53B and reaches the surface of the black photosensitive drum 31B, which is the surface to be scanned, and forms an image.

  As shown in FIG. 3, the optical sensor 23 is disposed in the vicinity of the reflection mirror 53Ya and the second fθ lens 52M and closer to the outside in the main scanning direction. The optical sensor 23 receives a laser beam reflected by the polygon mirror 41 of the optical deflector 40 that is outside the effective exposure area of the surface to be scanned. The laser light received by the optical sensor 23 is reflected toward the optical sensor 23 by the reflection mirror 24 provided in the vicinity of the second fθ lens 52B. The optical sensor 23 is a synchronization detection sensor for measuring the scanning timing of the laser beams LY, LM, LC, and LB corresponding to the four colors, and is called a BD sensor.

  Here, as shown in FIG. 3, an optical path adjusting mechanism 60 provided with an optical path adjusting mirror 61 (see FIG. 4) is provided on the optical path immediately upstream of the light traveling direction of the optical deflector 40. ing.

  Next, the configuration of the optical path adjusting mechanism 60 will be described in detail with reference to FIGS. 4 to 9 in addition to FIG. 4 is a partially enlarged top view around the optical path adjustment mechanism, FIG. 5 is a vertical sectional view around the optical path adjustment mechanism shown in FIG. 4, taken along line VV, FIG. 6 is a perspective view around the optical path adjustment mechanism, and FIG. FIG. 8 is a perspective view seen from the back side of the optical path adjusting mirror and the support member, and FIG. 9 is a perspective view of the pressing member. In FIG. 6, the drawing of the pressing member of the optical path adjustment mechanism is omitted.

  The optical path adjusting mechanism 60 reflects the laser light L emitted from the light source 22 and guides it to the polygon mirror 41 of the optical deflector 40 (see FIGS. 3 and 4). As shown in FIGS. 4 to 6, the optical path adjustment mechanism 60 includes an optical path adjustment mirror 61, a support member 62, a biasing member 63, a displacement member 64, a receiving portion 65, and a pressing member 66.

  The optical path adjustment mirror 61 is supported by the support member 62 and is disposed on the optical path of the laser light L emitted from the light source 22. The optical path adjustment mirror 61 has a flat plate shape, a reflection surface is formed on the front surface thereof, and reflects the laser light L.

  The support member 62 supports the optical path adjustment mirror 61 so that the back surface of the optical path adjustment mirror 61 is in close contact, and is provided to place the optical path adjustment mirror 61 on the optical path of the laser light L. As shown in FIGS. 7 and 8, the support member 62 includes a main body portion 62a having a substantially rectangular parallelepiped shape and a boss portion 62b. The bosses 62b are provided at both ends in the main scanning direction of the light beam of the main body 62a, that is, in the direction parallel to the horizontal direction, so as to protrude outward in that direction. The axes of the two boss portions 62b coincide.

  As shown in FIG. 7, the urging member 63 is attached to the support member 62 so as to press the optical path adjusting mirror 61 toward the support member 62. The urging member 63 includes a plate spring, and includes two arm portions 63a extending toward the reflection surface of the optical path adjustment mirror 61 so as to avoid a substantially central portion of the reflection surface. The support member 62 is sandwiched and held together.

  As shown in FIG. 8, the displacement member 64 is provided on the back side of the support member 62 with respect to the front side that supports the optical path adjustment mirror 61. The displacement member 64 is disposed at a substantially central portion in the vertical direction at a position corresponding to one end of the optical path adjustment mirror 61 in the main scanning direction of the light beam. The displacement member 64 is configured by a screw, extends straight from the back surface to the front surface of the support member 62 in a direction substantially perpendicular to the reflection surface of the optical path adjustment mirror 61, and the tip of the displacement member 64 is the back surface of the optical path adjustment mirror 61. Touching.

  When the displacement member 64 is screwed toward the optical path adjustment mirror 61, the support member is resisted against the elastic force of the urging member 63 with the one end of the optical path adjustment mirror 61 in the main scanning direction as the fulcrum. It will push in the direction away from 62. As a result, the displacement member 64 can rotationally displace the optical path adjusting mirror 61 about an axial center that is substantially parallel to the reflecting surface and perpendicular to the main scanning direction of the light beam, that is, substantially perpendicular. Therefore, the optical path adjustment mirror 61 can adjust the reflection point position of the light beam reaching the polygon mirror 41 of the optical deflector 40 with respect to the polygon mirror reflection surface.

  As shown in FIGS. 4 to 6, the receiving portion 65 is provided on the inner bottom surface of the housing 21 at a location corresponding to the optical path adjusting mechanism 60. The receiving portion 65 includes two V-shaped groove portions 65a shown in FIG. The two V-shaped groove portions 65a receive and hold the peripheral surfaces of the boss portions 62b provided at both ends in the main scanning direction of the support member 62, respectively. As a result, the support member 62 (optical path adjusting mirror 61) can rotate around the axis of the boss portion 62b, that is, an axis parallel to the main scanning direction of the light beam. Therefore, the optical path adjustment mirror 61 can adjust the reflection angle of the light beam reaching the polygon mirror 41 of the optical deflector 40 with respect to the polygon mirror reflection surface.

  As shown in FIGS. 4 and 5, the pressing member 66 is configured by a leaf spring, and is attached to the receiving portion 65. As shown in FIG. 9, the pressing member 66 includes two arm portions 66 a corresponding to the boss portions 62 b of the support member 62. This arm portion 66a is directed toward the V-shaped groove portion 65a so that the support member 62 can be accurately rotated around an axis parallel to the main scanning direction of the light beam without the support member 62 falling off the receiving portion 65. The boss 62b is pressed down.

  As described above, the light source 22 that emits the light beam, the light deflector 40 that deflects the light beam emitted from the light source 22 in the main scanning direction, and the light beam reflected by the light deflector 40 is scanned. In the optical scanning device 20 including the optical member group 50 guided onto the surface, the light beam reaching the light deflector 40 on the optical path upstream of the light deflector 40 in the light traveling direction with respect to the light deflector reflecting surface. Since the optical path adjustment mirror 61 capable of adjusting the reflection point position and reflection angle is provided, the position of the light beam reaching the polygon mirror 41 of the optical deflector 40 in the main scanning direction and the scanning line pitch in the sub-scanning direction are determined. It can be adjusted with high accuracy. And since those adjustments can be performed at one place, it is possible to reduce the labor involved in adjusting the installation angles of a plurality of other mirrors and lenses. In addition, even when the reflection surface of the polygon mirror 41 becomes narrow in response to the increase in speed, it is possible to perform highly accurate optical path adjustment on the reflection surface. In this manner, the deviation of the light beam irradiation position on the surface to be scanned can be corrected in accordance with the accuracy and error in manufacturing the housing 21, the lens, and the mirror of the optical scanning device 20. The optical scanning device 20 capable of obtaining a high-quality image can be provided.

  Further, the optical path adjusting mirror 61 can be rotated about an axis parallel to the main scanning direction of the light beam and can be rotated about an axis perpendicular to the main scanning direction of the light beam. The reflection point position and reflection angle of the light beam reaching the optical deflector 20 with respect to the optical deflector reflection surface can be adjusted. As a result, it is possible to further reduce the trouble of adjusting the position of the light beam reaching the optical deflector 20 in the main scanning direction and the scanning line pitch in the sub-scanning direction, and further adjust the optical path corresponding to high-speed printing. High accuracy can be achieved. Therefore, the image quality can be improved.

  Then, a support member 62 that supports the optical path adjustment mirror 61, a biasing member 63 that presses the optical path adjustment mirror 61 toward the support member 62, and a direction away from the support member 62 against the elastic force of the biasing member 63. The optical path adjustment mirror 61 is provided with a displacement member 64 for rotationally displacing the optical axis adjustment mirror 61 about the axis perpendicular to the main scanning direction of the light beam, so that the optical deflector 40 can be easily reached only by operating the displacement member 64. The reflection point position of the light beam with respect to the reflection surface of the optical deflector can be adjusted. Thereby, when performing highly accurate optical path adjustment corresponding to high-speed printing, the effort concerning adjustment of the position of the light beam reaching the optical deflector 40 in the main scanning direction can be further reduced.

  Further, the support member 62 is provided with boss portions 62b at both ends in the direction parallel to the main scanning direction of the light beam, and is provided with a V-shaped groove portion 65a for holding the location of the boss portion 62b of the support member 62. The optical path adjusting mirror 61 can be easily rotated about the axis parallel to the main scanning direction of the light beam along the V-shaped groove 65a. Thereby, the reflection angle of the light beam reaching the optical deflector 40 with respect to the optical deflector reflection surface can be adjusted with a simpler configuration. Therefore, it is possible to further reduce the labor involved in adjusting the scanning line pitch in the sub-scanning direction of the light beam reaching the optical deflector 40, and it is possible to further improve the optical path adjustment.

  Further, in the present invention, since the optical scanning device 20 is mounted on the image forming apparatus 1, the manufacturing of the housing 21, the lens, the mirror, and the like of the optical scanning device 20, and the accuracy of the assembly and the error are subject to scanning. It is possible to provide a high-performance image forming apparatus 1 that can correct the deviation of the light beam irradiation position on the surface and can obtain a high-quality image.

  Next, a detailed configuration of the optical scanning device according to the second embodiment of the present invention will be described with reference to FIGS. 10 is a partially enlarged top view of the periphery of the optical path adjustment mechanism of the optical scanning device, FIG. 11 is a vertical sectional view taken along line XI-XI around the optical path adjustment mechanism shown in FIG. 10, and FIG. FIG. 13 is a perspective view of the base member, and FIG. 14 is a perspective view of the support member. Note that the basic configuration of this embodiment is the same as that of the first embodiment described with reference to FIGS. 1 to 9, so the configuration common to the first embodiment is described in the drawings, and The description will be omitted.

  The optical path adjustment mechanism 60 of the optical scanning device 20 according to the second embodiment includes a base member 67 as shown in FIGS. 10 and 11. As shown in FIG. 12, the base member 67 has a box shape in which an upper surface is formed as an open portion and an opening 67 a for allowing laser light to pass through is provided on one side surface. A receiving portion 65 having two V-shaped groove portions 65 a is formed inside the base member 67. As shown in FIGS. 10 and 11, the base member 67 is provided with a support member 62 that holds the optical path adjustment mirror 61 in the receiving portion 65, and a pressing member 66 is attached.

  As shown in FIG. 13, a shaft portion 67 b is provided on the outer bottom surface of the base member 67 so as to protrude further downward. The shaft portion 67b is disposed at a position corresponding to a position substantially below the center of the optical path adjustment mirror 61 in the main scanning direction, and the axis extends in a direction substantially perpendicular, that is, a direction perpendicular to the main scanning direction of the light beam. As a result, the base member 67 can rotationally displace the support member 62 (optical path adjusting mirror 61) about an axis that is substantially parallel to the reflecting surface and perpendicular to the main scanning direction of the light beam. Accordingly, the base member 67 can adjust the position of the reflection point of the light beam reaching the polygon mirror 41 of the optical deflector 40 with respect to the polygon mirror reflection surface.

  As shown in FIG. 14, the support member 62 includes a handle 62c at the top thereof. When the handle 62c is held and operated, the support member 62 (optical path adjusting mirror 61) has an axis parallel to the main scanning direction of the light beam, that is, the axis of the boss 62b, as indicated by an arrow in FIG. It can rotate around the center. The optical path adjustment mirror 61 is attached to the front surface of the support member 62 without using the biasing member 63 and the displacement member 64 (see FIGS. 7 and 8).

  As described above, the support member 62 that supports the optical path adjustment mirror 61 and the shaft portion 67b that holds the support member 62 and rotates the support member 62 about the axis that is perpendicular to the main scanning direction of the light beam are provided. Therefore, it is possible to easily adjust the position of the reflection point of the light beam reaching the light deflector 40 with respect to the light deflector reflecting surface simply by operating the base member 67. Thereby, when performing highly accurate optical path adjustment corresponding to high-speed printing, the effort concerning adjustment of the position of the light beam reaching the optical deflector 40 in the main scanning direction can be further reduced.

  Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention.

  For example, in the embodiment of the present invention, an optical scanning device mounted on a tandem type image forming apparatus provided with four photosensitive drums has been described as an example, but the target optical scanning device is in this form. However, the present invention is not limited thereto, and may be an optical scanning device mounted on another type of image forming apparatus.

  The present invention can be used in all optical scanning devices.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 20 Optical scanning device 21 Housing 22 Light source 40 Optical deflector 41 Polygon mirror 60 Optical path adjustment mechanism 61 Optical path adjustment mirror 62 Support member 62b Boss part 63 Biasing member 64 Displacement member 65 Receiving part 65a V-shaped groove part 66 Holding member 67 Base member 67b Shaft

Claims (6)

A light source for irradiating a light beam, a light deflector for deflecting the light beam emitted from the light source in the main scanning direction, and an optical member group for guiding the light beam reflected by the light deflector onto the surface to be scanned. In the optical scanning device provided,
An optical path adjustment mirror capable of adjusting a reflection point position and a reflection angle of a light beam reaching the optical deflector with respect to the optical deflector reflection surface is provided on the optical path upstream of the optical deflector in the light traveling direction. Optical scanning device.   2. The optical path adjusting mirror according to claim 1, wherein the optical path adjusting mirror is rotatable about an axis parallel to the main scanning direction of the light beam and is rotatable about an axis center perpendicular to the main scanning direction of the light beam. The optical scanning device described.   A support member that supports the optical path adjustment mirror; an urging member that presses the optical path adjustment mirror toward the support member; and the optical path adjustment mirror that moves away from the support member against the elastic force of the urging member. The optical scanning device according to claim 1, further comprising: a displacement member that is rotationally displaced about an axis that is perpendicular to the main scanning direction.   A support member that supports the optical path adjustment mirror; and a base member that holds the support member and is provided with a shaft portion that rotates the support member about an axis that is perpendicular to the main scanning direction of the light beam. The optical scanning device according to claim 1, wherein the optical scanning device is characterized.   The boss part is provided in the both ends of the said support member in the direction parallel to the main scanning direction of a light beam, The V-shaped groove part which hold | maintains the location of the boss | hub part of this support member is provided. The optical scanning device according to claim 4.   An image forming apparatus comprising the optical scanning device according to claim 1.

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