JP6840563B2 - Optical scanning device and image forming device - Google Patents

Description

The present invention relates to an optical scanning device used in an image forming device such as a copier, a printer, a facsimile, and a multifunction device thereof, and an image forming device including the optical scanning device.

As an optical scanning apparatus used in an electrophotographic image forming apparatus, an optical scanning apparatus having the following configuration is well known. That is, the light beam emitted from the light source is deflected by a rotating multifaceted mirror, and the deflected light beam is guided onto the photosensitive surface of the photoconductor by an optical component such as a lens or a mirror, thereby producing a latent image on the photoconductor. It is an optical scanning device to be formed.

Inside the optical scanning device, a deflector having a rotating multifaceted mirror is provided for deflecting and scanning the laser light emitted from the semiconductor laser. The laser beam is scanned on the photoconductor by a rotating multifaceted mirror, and the semiconductor laser is repeatedly emitted and turned off in accordance with the operation of the photoconductor, so that a predetermined latent image image can be obtained on the photoconductor.

The scanning imaging optical system has a reflection mirror that reflects the laser beam and guides the laser beam to the photoconductor. The reflection mirror has a long shape in a direction parallel to the scanning direction of the laser beam. The reflective mirror is installed on a seating surface provided on the housing. The seat surface provided on the housing is also used for positioning the reflection mirror, and needs to be arranged in the vicinity of the side wall surface of the housing. In the housing of the optical scanning device, it is necessary to enable the functions to be exhibited even if the shape provided for exerting other functions and the seating surface of the reflection mirror are close to each other.

For example, a hole is provided on the side wall surface of the housing of the optical scanning device, and the hole and the duct are communicated with each other to guide an air flow containing dust and dirt to the duct to prevent dust and dirt from entering the housing. Is disclosed (see, for example, Patent Document 1). In addition, the deflector is a cause of generating an air flow toward the inside of the optical scanning device. For example, a configuration is disclosed in which a duct is provided around the deflector to limit the place where outside air enters (see, for example, Patent Document 2). By providing a structure for catching dust and dirt in the duct, dust and dirt are prevented from entering the optical scanning device.

Japanese Unexamined Patent Publication No. 2009-217091 Japanese Unexamined Patent Publication No. 2010-113329

In order to achieve both the miniaturization of the optical scanning device and the configuration for preventing the inflow of dust and dirt into the optical scanning device, the following measures are required. The seating surface for installing the reflective mirror provided in the housing and the configuration provided for exerting other functions of the housing are arranged so as not to interfere with each other's functions. Need to be.

The present invention has been made under such circumstances, and an object of the present invention is to achieve both miniaturization of an optical scanning apparatus and a dustproof function.

In order to solve the above-mentioned problems, the present invention includes the following configurations.

(1) An optical scanning device attached to an image forming apparatus including a first photoconductor and a plurality of photoconductors including the second photoconductor, and light attached to the lower side in the vertical direction of the plurality of photoconductors. In the scanning apparatus, the first light source that emits a first laser beam that exposes the first photoconductor and the second light source that emits a second laser beam that exposes the second photoconductor are used. A rotating multifaceted mirror that deflects a plurality of light sources including the mirrors and laser beams emitted from the plurality of light sources so that the first laser beam and the second laser beam are incident on the same reflecting surface. A rotating multifaceted mirror arranged with respect to the first light source and the second light source, a plurality of optical members for guiding laser light deflected by the rotating multifaceted mirror to corresponding photoconductors, a bottom surface, and the above. A housing having a side wall surface erected from the bottom surface, the plurality of light sources are attached to the side wall surface, and the rotating multifaceted mirror and the plurality of optical members are housed therein, and the side wall surface from the side wall surface. The first laser beam extending toward the rotating multi-sided mirror inside the housing and emitted from the first light source toward the rotating multi-faceted mirror and the rotating multi-sided mirror emitted from the second light source. A tubular portion through which the second laser beam heading toward is passed through the inside, and supports the tubular portion integrally formed in the housing and the plurality of optical members formed in the housing. The rotary multifaceted mirror is arranged at a position closer to the second photoconductor than the first photoconductor, and the tubular portion is provided with a surface on the outer periphery of the tubular portion. The normal vector has a slope toward the space side where the first photoconductor and the second light source are arranged, and one of the plurality of support portions is provided on the slope. An optical scanning device characterized in that the support portion supports one mirror that guides the second laser beam to the second photoconductor among the plurality of optical members.

(2) A photoconductor, an optical scanning device according to (1) for forming a latent image on the photoconductor, and a developing means for developing a latent image formed by the optical scanning device with toner to form a toner image. An image forming apparatus including a transfer means for transferring a toner image formed by the developing means to a transfer target.

According to the present invention, both the miniaturization of the optical scanning device and the dustproof function can be achieved at the same time.

The figure which shows the structure of the image forming apparatus of an Example A perspective view and a cross-sectional view showing the configuration of the optical scanning apparatus of the embodiment. Sectional drawing of the cylinder part of the housing of the optical scanning apparatus of an Example Explanatory drawing of an optical scanning apparatus when miniaturization of an embodiment was attempted. Cross-sectional view of an optical scanning device when there is a seating surface on the slope of the tubular portion of the embodiment. Cross-sectional view of an optical scanning device when there is a seating surface on the upper part of the tubular portion of the embodiment. Sectional drawing explaining the optical path of the laser beam of an Example

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings by way of examples. In the following description, the rotation axis direction of the rotating polymorphic mirror is the Z-axis direction, the main scanning direction which is the scanning direction of the laser beam or the longitudinal direction of the mirror is the Y-axis direction, and the direction perpendicular to the Y-axis and the Z-axis is X. Axial direction.

[Configuration of image forming apparatus]
The configuration of the image forming apparatus of the embodiment will be described. FIG. 1 is a schematic configuration diagram showing the overall configuration of the tandem type color laser beam printer of the embodiment. This laser beam printer (hereinafter, simply referred to as a printer) has four image-forming engines 10Y and 10M that form toner images for each of the colors yellow (Y), magenta (M), cyan (C), and black (Bk). It is provided with 10C and 10Bk (shown by a long and short dash line). Further, the printer includes an intermediate transfer belt 20 which is a transfer target to which a toner image is transferred from each image formation engine 10Y, 10M, 10C, 10Bk. The toner image multiplex-transferred to the intermediate transfer belt 20 is configured to be transferred to a recording sheet P, which is a recording medium, to form a full-color image. Hereinafter, the symbols Y, M, C, and Bk representing each color will be omitted unless necessary.

The intermediate transfer belt 20 is formed in an endless shape and is hung around a pair of belt transport rollers 21 and 22, and the toner image formed by each image forming engine 10 is transferred while rotating in the direction of arrow H. It is configured as follows. Further, a secondary transfer roller 30 is arranged at a position facing one of the belt transport rollers 21 with the intermediate transfer belt 20 in between. The recording sheet P is inserted between the secondary transfer roller 30 and the intermediate transfer belt 20 which are in pressure contact with each other, and the toner image is transferred from the intermediate transfer belt 20. The four image-forming engines 10Y, 10M, 10C, and 10Bk described above are arranged in parallel on the lower side of the intermediate transfer belt 20, and a toner image formed according to the image information of each color is formed on the intermediate transfer belt. It is designed to be transferred to 20 (hereinafter referred to as primary transfer). These four image-forming engines 10 are the image-forming engine 10Y for yellow, the image-forming engine 10M for magenta, and the image-forming engine 10C for cyan along the rotation direction (arrow H direction) of the intermediate transfer belt 20. And the image-forming engine for black 10Bk are arranged in this order.

Further, on the lower side in the vertical direction of the image forming engine 10, an optical scanning device 40 for exposing the photosensitive drum (photoreceptor) 50, which is an object to be scanned, provided in each image forming engine 10 according to image information is arranged. Has been done. The optical scanning device 40 is shared by all image forming engines 10Y, 10M, 10C, and 10Bk, and four semiconductor lasers 52 (light beams) that emit laser light (light beam) modulated according to the image information of each color ( (See 52a in FIG. 3). Further, the optical scanning device 40 includes a rotating multifaceted mirror 42 that rotates at high speed and scans the laser light of these four optical paths along the rotation axis direction of the photosensitive drum 50 (see FIG. 2 and the like).

Each laser beam scanned by the rotating multi-sided mirror 42 travels on a predetermined path while being guided by an optical member installed in the optical scanning device 40. Each laser beam traveling along a predetermined path exposes each photosensitive drum 50 of each image forming engine 10 through each irradiation port (also referred to as a transparent window) (not shown) provided in the upper part of the optical scanning device 40. The rotating multifaceted mirror 42 is arranged at a position closer to the photosensitive drum 50M, which is the second photoconductor, than the photosensitive drum 50Y, which is the first photoconductor.

Further, each image forming engine 10 includes a photosensitive drum 50 and a charging roller 12 that charges the photosensitive drum 50 to a uniform background potential. Further, each image forming engine 10 includes a developer 13 that develops an electrostatic latent image formed on the photosensitive drum 50 (on the object to be scanned) by exposure to laser light to form a toner image. The developer 13 forms a toner image corresponding to the image information of each color on the photosensitive drum 50 which is a photoconductor. The developer 13 is a method using a two-component developer in which toner and carriers are mixed. The developer 13 is replenished with a developer in which toner and carriers are mixed from a replenishment cartridge (not shown) in order to omit maintenance for replacement of the developer due to changes with time. For the developer 13, a developing method is used in which the deteriorated developer is automatically discharged.

A primary transfer roller 15 is arranged at a position facing the photosensitive drum 50 of each image forming engine 10 so as to sandwich the intermediate transfer belt 20. When a predetermined transfer voltage is applied to the primary transfer roller 15, the toner image on the photosensitive drum 50 is transferred to the intermediate transfer belt 20.

On the other hand, the recording sheet P is supplied from the paper feed cassette 2 housed in the lower part of the printer housing 1 to the inside of the printer, specifically, the secondary transfer position where the intermediate transfer belt 20 and the secondary transfer roller 30 come into contact with each other. Will be done. A pickup roller 24 and a paper feed roller 25 for pulling out the recording sheet P housed in the paper feed cassette 2 are arranged side by side on the upper portion of the paper feed cassette 2. Further, a retard roller 26 for preventing double feeding of the recording sheet P is arranged at a position facing the paper feed roller 25. The transport path 27 of the recording sheet P inside the printer is provided substantially vertically along the right side surface of the printer housing 1. The recording sheet P pulled out from the paper feed cassette 2 located at the bottom of the printer housing 1 rises the transport path 27 and is fed to the registration roller 29 that controls the entry timing of the recording sheet P with respect to the secondary transfer position. Be done. After that, the recording sheet P is transferred to the fuser 3 (shown by the broken line) provided on the downstream side in the transport direction after the toner image is transferred at the secondary transfer position. Then, the recording sheet P on which the toner image is fixed by the fixing device 3 is discharged to the discharge tray 1a provided on the upper portion of the printer housing 1 via the discharge roller 28.

In forming a full-color image by the color laser beam printer configured in this way, first, the optical scanning device 40 exposes the photosensitive drum 50 of each image formation engine 10 at a predetermined timing according to the image information of each color. As a result, a latent image image corresponding to the image information is formed on the photosensitive drum 50 of each image forming engine 10. Here, in order to obtain high-quality image quality, the latent image image formed by the optical scanning device 40 must be accurately reproduced at a predetermined position on the photosensitive drum 50.

In recent years, the image forming apparatus is required to reduce the installation area of the image forming apparatus by, for example, reducing the width in the lateral direction (X-axis direction) in FIG. As a means for reducing the installation area of the image forming apparatus, it is conceivable to make the interval between the image forming engines 10 narrower than before. When the distance between the image-forming engines 10 is narrower than before, it is affected by the fact that the distance between the photosensitive drums 50 is narrower than before.

[Optical scanning device]
FIG. 2A is a perspective view of the optical scanning device 40 in which the upper lid 69 (see FIG. 2B) of the optical scanning device 40 is removed so that the rotating multifaceted mirror 42, optical components, and the like can be seen. For example, in the embodiment, one light source unit 51 (see 51a and 51b in FIG. 3), which is a light source, is provided for one image-forming engine 10. Specifically, the light source unit 51a corresponds to the image forming engine 10Y, the light source unit 51b corresponds to the image forming engine 10M, the light source unit 51c corresponds to the image forming engine 10C, and the image forming engine 10Bk corresponds to the light source unit 51c. The light source unit 51d corresponds (see FIG. 5A). In the rotating multifaceted mirror 42, the first laser light emitted from the light source unit 51a, which is the first light source, and the second laser light emitted from the light source unit 51b, which is the second light source, are incident on the same reflecting surface. As described above, they are arranged with respect to the light source units 51a and 51b. In the following description, the description of the subscripts a to d of the reference numerals will be omitted unless necessary.

The light source unit 51 is mounted on the circuit board 45 together with a laser driver (not shown) that drives the light source unit 51. The circuit board 45 is attached to a side wall surface 101d erected from the bottom surface of the housing 101. Specifically, the two light source units 51a and 51b, which are a plurality of light sources, are mounted on the circuit board 45a, and the two light source units 51c and 51d are mounted on the circuit board 45b. The optical paths of the laser beams emitted from the light source units 51a and 51b are mounted on the circuit board 45a so as to have an angular difference in the main scanning direction and the sub-scanning direction from each other (see FIG. 3). The two circuit boards 45a and 45b are attached to the side wall surface 101d of the housing 101 as shown in FIG. 2A. A light receiving sensor 55, which will be described later, is mounted on the circuit board 45a.

A rotating multi-sided mirror 42 that deflects the laser light emitted from the light source unit 51 and a scanner motor 41 that rotates the rotating multi-sided mirror 42 are attached to the bottom surface of the housing 101. The laser light emitted from the light source unit 51 is reflected by the rotating multifaceted mirror 42, and the laser light reflected by the rotating multifaceted mirror 42 is directed to the photosensitive drum 50 which is the surface to be scanned. Further, the laser light reflected by the rotating multi-sided mirror 42 goes to the light receiving sensor 55, which is a detection means mounted on the circuit board 45.

It is necessary to operate in a state where the time from the timing when the laser light is received by the light receiving sensor 55 to the start of the formation of the latent image by the laser light in the photosensitive drum 50 is kept constant. The light receiving sensor 55 is arranged to operate while keeping this time constant. That is, the light receiving sensor 55 is used to determine the timing at which the laser beam is emitted from the light source units 51a and 51b. The light receiving sensor 55 is arranged directly above the light source unit 51a (in the + Z direction) (see FIG. 5). The laser light directed to the light receiving sensor 55 and the laser light emitted from the light source unit 51a have a relationship that does not have an angular difference in the main scanning direction. On the other hand, a plurality of light source units 51 are arranged in the optical scanning device 40. For example, the light source units 51a and 51b and the light source are located on the + X side and the −X side with reference to the YZ plane including the rotation axis of the rotating multifaceted mirror 42. Units 51c and 51d are provided. For example, the optical paths of the laser light emitted from the light source unit 51a and the light source unit 51b, which are the two light sources on one side, are provided with different angles in the main scanning direction (see FIG. 5A). The optical paths of the laser light emitted from the two light source units 51a and 51b are provided with an angle difference in the main scanning direction for the following reasons. That is, even if the sizes of the light source units 51a and 51b are increased, in order to arrange the light source units 51a and 51b so that the oblique incident angle in the sub-scanning direction is small, the optical paths of the two laser beams are arranged in the main scanning direction. There is an angle difference.

When the circuit board 45 is attached to the side wall surface 101d of the optical scanning device 40, the light source unit 51 is in a state of projecting inside the optical scanning device 40 (see FIG. 3). Therefore, the housing 101 has a partition wall portion (hereinafter, referred to as a tubular portion 101b) having a shape that covers the light source unit 51. The side wall surface 101d of the housing 101 to which the circuit board 45 is mounted is provided with an opening 101c so that the laser light emitted from the light source unit 51 is guided to the rotating multifaceted mirror 42 (see FIG. 6). The opening 101c connects the inside of the optical scanning device 40 and the outside of the optical scanning device 40. That is, the outside air outside the optical scanning device 40 can enter the optical scanning device 40 through the opening 101c. Therefore, the opening 101c needs to be sealed by a sealing member that seals the opening 101c. In the embodiment, the cylinder lens 65 also functions as a sealing member for sealing the opening 101c. The opening 101c is provided at the tip of the tubular portion 101b, which is a place where the sealing member can be easily installed. The tubular portion 101b is a partition wall for separating the outside and the inside of the optical scanning device 40. The opening 101c is provided to allow the laser light emitted from the light source unit 51a to pass from the outside of the housing 101 to the inside of the housing 101. Further, the opening 101c is also provided to allow the laser light to pass from the inside of the housing 101 to the outside of the housing 101 because the laser light reflected by the rotating multifaceted mirror 42 is received by the light receiving sensor 55. There is. The tubular portion 101b, the slope portion 101a, and the mirror seat surface 70 will be described later.

[Optical path of laser light]
The optical scanning device 40 is provided with optical lenses 60a to 60f for guiding each laser beam onto the photosensitive drum 50 and forming an image, and reflection mirrors 62a to 62h which are optical components. For the sake of readability of the figure, reference numerals 60a to 60f and 62a to 62h are not shown in FIG. 2A. The housing 101 internally houses the rotary multifaceted mirror 42 and the reflective mirrors 62a to 62h. A state in which the laser beam is guided to the photosensitive drum 50 by the optical lenses 60a to 60f and the reflection mirrors 62a to 62h will be described with reference to FIG. 2B. FIG. 2B is a schematic cross-sectional view showing an overall image of the optical scanning apparatus 40 to which the optical components are attached. The laser beam LY corresponding to the photosensitive drum 50Y emitted from the light source unit 51a is deflected by the rotating multifaceted mirror 42 and incident on the optical lens 60a. The laser beam LY that has passed through the optical lens 60a is incident on the optical lens 60b, passes through the optical lens 60b, and is reflected by the reflection mirror 62a. The laser beam LY reflected by the reflection mirror 62a passes through the transparent window and scans the photosensitive drum 50Y. The reflection mirror that reflects the laser light LY is one reflection mirror 62a.

The laser beam LM corresponding to the photosensitive drum 50M emitted from the light source unit 51b is deflected by the rotating multifaceted mirror 42 and incident on the optical lens 60a. The laser beam LM that has passed through the optical lens 60a is reflected by the reflection mirror 62b and the reflection mirror 62c, is incident on the optical lens 60e, passes through the optical lens 60e, and is reflected by the reflection mirror 62d. The laser beam LM reflected by the reflection mirror 62d passes through the transparent window and scans the photosensitive drum 50M. The reflection mirrors that reflect the laser light LM, which is one laser light, are the reflection mirrors 62b, 62c, and 62d. Among the reflection mirrors 62b, 62c, and 62d, the reflection mirror that last reflects the laser beam LM is the reflection mirror 62d. Hereinafter, the reflection mirror 62d is also referred to as a reflection mirror 44a.

The laser beam LC corresponding to the photosensitive drum 50C emitted from the light source unit 51c is deflected by the rotating multifaceted mirror 42 and incident on the optical lens 60c. The laser light LC that has passed through the optical lens 60c is reflected by the reflection mirror 62e and the reflection mirror 62f and is incident on the optical lens 60f, and the laser light LC that has passed through the optical lens 60f is reflected by the reflection mirror 62g. The laser beam LC reflected by the reflection mirror 62g passes through the transparent window and scans the photosensitive drum 50C. Among the reflection mirrors 62e, 62f, and 62g, the reflection mirror that reflects the laser light LC, which is one laser light, is the reflection mirror 62g, and the reflection mirror that last reflects the laser light LC is the reflection mirror 62g. Hereinafter, the reflection mirror 62g is also referred to as a reflection mirror 44a.

The laser beam LBk corresponding to the photosensitive drum 50Bk emitted from the light source unit 51d is deflected by the rotating multifaceted mirror 42 and incident on the optical lens 60c. The laser beam LBk that has passed through the optical lens 60c is incident on the optical lens 60d, passes through the optical lens 60d, and is reflected by the reflection mirror 62h. The laser beam LBk reflected by the reflection mirror 62h passes through the transparent window and scans the photosensitive drum 50Bk. The reflection mirror that reflects the laser light LBk is one reflection mirror 62h. In the following description, the optical lenses 60a to 60d are collectively referred to as an optical lens 60, and the reflection mirrors 62a to 62h are collectively referred to as a reflection mirror 62.

[Cylinder]
FIG. 3 is a cross-sectional view taken along the line AA of FIG. 2A, which is a cross-sectional view taken through the light source unit 51a and the rotation axis of the rotary multifaceted mirror 42 and cut along a plane parallel to the rotating axis of the rotating multifaceted mirror 42. is there. The tubular portion 101b is a tunnel-shaped portion that extends from the side wall surface 101d toward the inside of the housing 101 and allows the laser light emitted from the light source unit 51 to pass through the inside. The tubular portion 101b is integrally formed with the housing 101. The light source unit 51a includes a semiconductor laser 52a, a collimator lens 53a, and a diaphragm 54a. The light source units 51b, 51c, and 51d are also configured in the same manner as the light source unit 51a. The diffused light emitted from the semiconductor laser 52a is converted into parallel light by the collimator lens 53a. The laser light that has become parallel light by the collimator lens 53a is focused on the mirror surface of the rotating multifaceted mirror 42 by the cylinder lens 65. The cylinder lens 65 is installed at a position closer to the rotating multifaceted mirror 42 than the mirror seating surface 70, which is a support portion of the reflecting mirror 44a.

In order to reduce the size of the optical scanning device 40, the light source unit 51 is attached to the side wall surface 101d of the housing 101. The housing 101 is provided with a tubular portion 101b that covers the light source unit 51. As shown in FIG. 3, the cylinder portion 101b is formed as a tunnel shape protruding inside the housing 101 in order to keep a distance between the collimator lens 53 and the cylinder lens 65. The housing 101 is provided with an opening 101c through which the laser light emitted from the light source unit 51 passes. The opening 101c is provided at the tip of the tubular portion 101b on the inner side of the housing 101. The cylinder portion 101b is extended to the vicinity of the cylinder lens 65 in order to improve the dust resistance inside the housing 101.

[Miniaturization of image forming part]
FIG. 4 (a) shows a schematic view of a main part of the image forming apparatus when the interval between the photosensitive drums 50 is the conventional interval, and FIG. 4 (b) shows the interval between the photosensitive drums 50 as compared with the conventional one. A schematic diagram of the main part of the image forming apparatus when narrowed is shown. Here, the reflection mirror 44a is a reflection mirror for guiding the laser light to the two photosensitive drums 50M and 50C arranged near the rotating multifaceted mirror 42 among the four photosensitive drums 50 (FIG. 2B). 62d, 62g). Further, the reflection mirror 44a is a reflection mirror that finally reflects the laser light among the plurality of reflection mirrors that guide the laser light reflected by the rotating multifaceted mirror 42 to the photosensitive drums 50M and 50C.

In the image forming apparatus of FIG. 4B, as compared with the image forming apparatus of FIG. 4A, the reflection mirror 44a is centered in the left-right direction of the optical scanning apparatus 40 (installation position of the rotating multifaceted mirror 42). Is approaching. When the two reflection mirrors 44a are closer to the rotating multifaceted mirror 42 than before, the light source unit 51a, the optical path of the laser light emitted from the light source unit 51a, the optical path of the laser light toward the light receiving sensor 55, and the reflection mirror 44a. Will be closer to. Further, when the reflective mirror 44a is installed in the housing, the position of the mirror seating surface 70, which will be described later, which supports the reflective mirror 44a, and the above-mentioned tubular portion 101b interfere with each other. In the following description, the present embodiment relates to a tubular portion 101b that covers two light source units 51a and 51b on a circuit board 45a provided with a light receiving sensor 55, and a mirror seat surface 70 of a reflection mirror 62d (44a). The case of application will be described. However, this embodiment may be applied to the tubular portion covering the two light source units 51c and 51d on the circuit board 45b on which the light receiving sensor 55 is not provided, and the reflection mirror 62g (44a).

[Position of the seating surface of the reflective mirror]
FIG. 5A is a perspective view of a part of the optical scanning device 40 as viewed from the direction (+ side of the Y axis) from the rotary multifaceted mirror 42 toward the light source unit 51. At one corner of the tubular portion 101b having a shape that covers the light source unit 51, a part of the shape is a surface shape (hereinafter, referred to as a slope portion) 101a. The slope portion 101a is provided so that the surface normal vector N (broken line arrow in FIG. 5A) is not parallel to the rotation axis of the rotating polyplane mirror 42 and is not orthogonal to the rotation axis. Further, the slope portion 101a is provided so that the normal vector N of the surface is oriented away from the rotation axis of the rotary multifaceted mirror 42.

FIG. 5B is an enlarged view of the vicinity of the slope portion 101a. A mirror seat surface 70 for installing the reflection mirror 44a is provided on the portion of the tubular portion 101b where the slope portion 101a exists. The reflection mirror 44a is fixed to the mirror seat surface 70 provided on the slope portion 101a of the tubular portion 101b. The mirror seat surface 70 exists directly above the optical path of the laser beam LY emitted from the light source unit 51a and the optical path of the laser beam reflected by the rotating multifaceted mirror 42 toward the light receiving sensor 55 in the Z direction. That is, the mirror seat surface 70 is provided on the tubular portion 101b to support the reflective mirror 44a on the housing 101. The mirror seat surface 70 is provided above the optical path of the laser light emitted from the light source unit 51a, which is one of the light sources units 51a and 51b, which are a plurality of light sources, in the rotation axis direction of the rotating multifaceted mirror 42. Has been done. Further, the mirror seat surface 70 is provided above the optical path of the laser beam emitted from the light source unit 51a and deflected by the rotating multifaceted mirror 42 toward the light receiving sensor 55 in the rotation axis direction of the rotating multifaceted mirror 42.

The laser beam reflected by the rotating multi-sided mirror 42 and directed toward the light receiving sensor 55 has an angle difference with respect to the horizontal direction (XY plane). The surface of the slope portion 101a of the tubular portion 101b is formed as a surface substantially parallel to the laser beam directed to the light receiving sensor 55. By forming the surface of the slope portion 101a so as to be parallel to the optical path of the laser light toward the light receiving sensor 55, the distance between the housing 101 and the laser light toward the light receiving sensor 55 can be minimized. The mirror seat surface 70 is provided directly above the optical path of the laser beam toward the light receiving sensor 55. As a result, the reflection mirror 44a can be arranged at a position closest to the bottom surface of the optical scanning device 40 in the rotation axis direction (vertical direction / gravity direction) of the rotary multifaceted mirror 42.

As described above, the tubular portion 101b has a slope portion 101a whose surface normal vector faces the space side where the photosensitive drum 50Y and the photosensitive drum 50M are arranged on the outer periphery of the tubular portion 101b. One of the plurality of support portions is provided on the slope portion 101a, and the support portion supports one mirror that guides a second laser beam to the photosensitive drum 50M among the plurality of optical members.

FIG. 6 is a perspective view of the optical scanning device 40 when the slope portion 101a is not provided on the tubular portion 101b having a shape that covers the light source unit 51 of the housing 101. When the slope portion 101a is not provided, the mirror seat surface 70 of the reflection mirror 44a is provided on the upper surface 101e of the tubular portion 101b. The upper surface 101e of the tubular portion 101b is a surface parallel to the lower surface of the housing 101. When the mirror seat surface 70 is provided on the upper surface 101e of the tubular portion 101b, the reflection mirror 44a is about 5 mm in the rotation axis direction of the rotary multifaceted mirror 42, as compared with the case of FIG. 5A, and the optical scanning device 40. It is placed away from the bottom of the. As a result, the height of the side wall surface 101d of the housing 101 from the bottom surface of the optical scanning device 40 in the case of FIG. 6 is also about 5 mm higher than that in the case of FIG. 5A. Assuming that the height of the side wall surface 101d of the housing 101 in FIG. 5A is Z1 (mm) and the height of the side wall surface of the housing 101 in FIG. 6 is Z2 (mm), Z2 = Z1 + 5 (mm). ing.

The reflection mirror 44a is a component (see FIG. 2B) that is arranged at the position farthest from the bottom surface of the optical scanning device 40 among the optical components (mirrors and lenses) of the optical scanning device 40 (see FIG. 2B). Therefore, by adopting the configuration as shown in FIG. 5, the size (that is, the height) of the rotating multifaceted mirror 42 of the optical scanning device 40 in the rotation axis direction can be made smaller than before.

In the optical scanning device 40 of the embodiment, an example in which the light receiving sensor 55 is arranged directly above the light source unit 51 has been described. However, when the light receiving sensor 55 is not arranged directly above the light source unit 51a and is arranged with an angle difference in the main scanning direction with respect to the light source unit 51a, the same effect is exhibited and the optical scanning is performed. The size of the device 40 can be reduced.

FIG. 7A illustrates a part of the optical scanning device 40 and the laser beam passing in the vicinity of the reflection mirror 44a. FIG. 7B is an enlarged view of the vicinity of the slope portion 101a. The photosensitive drum 50 is housed in a unit 125 provided with an opening in a portion through which the laser beam reflected by the reflection mirror 44a passes. In FIG. 7, the photosensitive drum 50M and the unit 125 of the photosensitive drum 50M are shown. The optical path 200a of the laser beam is an optical path of the laser beam that is guided to a predetermined position on the photosensitive drum 50M and passes through a predetermined position. The optical path 200b of the laser beam is an optical path of the laser beam that is not guided on the photosensitive drum 50 and passes through a position other than a predetermined position. In the optical scanning device 40, the reflection mirror 44a is installed on the mirror seat surface 70 so that the reflection surface 44aR of the reflection mirror 44a and the surface 101aS of the slope portion 101a of the tubular portion 101b of the housing 101 are parallel to each other. (Fig. 7 (b) broken line). The laser beam passing through the optical path 200b is reflected by the slope portion 101a of the tubular portion 101b and is not irradiated on the photosensitive drum 50. In this way, the reflection surface 44aR of the reflection mirror 44a and the surface 101aS of the slope portion 101a are made parallel to each other. As a result, even when an unintended laser beam passes through the optical path 200b and heads toward the photosensitive drum 50M, the unit 125 blocks the laser beam passing through the optical path 200b. This makes it possible to prevent image defects due to unintended laser light.

In the housing 101 of the optical scanning device 40, the tubular portion 101b having a shape that covers the periphery of the light source unit 51 and the opening 101c that communicates with the inside and outside of the housing 101 are arranged close to each other. The aperture 101c is sealed by the cylinder lens 65 required for condensing the laser beam on the photosensitive drum 50. This makes it possible to reduce the size by preventing the inflow of dust, dust, etc. into the inside of the housing 101. Specifically, the mirror seat surface is integrated with the tubular portion 101b, which has a shape that covers the periphery of the light source unit 51, and is directly above the optical path where the laser light reflected by the rotating multifaceted mirror 42 faces the light receiving sensor 55. 70 is provided. This makes it possible to achieve both dustproofness and miniaturization of the optical scanning device 40.

As described above, the slope portion 101a is provided on the tubular portion 101b, which is the partition wall of the housing 101 that separates the inside and the outside of the optical scanning device 40, and the mirror seat surface 70 of the reflection mirror 44a is provided on the slope portion 101a.
This makes it possible to reduce the size of the optical scanning device 40 while preventing dust inside the optical scanning device 40. As described above, according to the embodiment, it is possible to achieve both the miniaturization of the optical scanning device and the dustproof function.

40 Optical scanning device 42 Rotating multi-sided mirror 44a Reflective mirror 50 Photosensitive drum 51 Light source unit 70 Mirror seat surface 101 Housing 101a Slope 101b Cylinder

Claims (9)

An optical scanning device attached to an image forming apparatus including a first photoconductor and a plurality of photoconductors including a second photoconductor, and the optical scanning device attached to the lower side in the vertical direction of the plurality of photoconductors. ,
A plurality of light sources including the first light source that emits a first laser beam that exposes the first photoconductor and a second light source that emits a second laser beam that exposes the second photoconductor. When,
A rotating multifaceted mirror that deflects laser light emitted from the plurality of light sources, the first light source and the first light source so that the first laser light and the second laser light are incident on the same reflecting surface. A rotating multi-sided mirror arranged for two light sources,
A plurality of optical members for guiding the laser beam deflected by the rotating multi-sided mirror to the corresponding photoconductors, and
A housing having a bottom surface and a side wall surface erected from the bottom surface, the plurality of light sources are attached to the side wall surface, and the rotating multifaceted mirror and the plurality of optical members are housed therein.
The first laser beam and the second light source that extend from the side wall surface toward the rotating polymorphic mirror inside the housing and are emitted from the first light source and directed toward the rotating multifaceted mirror are emitted. A tubular portion through which the second laser beam directed toward the rotary multifaceted mirror passes through the inside, and the tubular portion integrally formed with the housing.
A plurality of support portions formed in the housing and for supporting the plurality of optical members, respectively.
With
The rotating multifaceted mirror is arranged at a position closer to the second photoconductor than the first photoconductor.
The tubular portion has a slope having a surface normal vector on the outer periphery of the tubular portion toward the space side where the first photoconductor and the second photoconductor are arranged.
One of the plurality of support portions is provided on the slope, and the support portion supports one mirror that guides the second laser beam to the second photoconductor among the plurality of optical members. An optical scanning device characterized by being A lens for condensing laser light emitted from the plurality of light sources on the rotating multi-sided mirror is provided.
The optical scanning apparatus according to claim 1, wherein the lens is arranged at a position closer to the rotating multifaceted mirror than the support portion. The tubular portion is provided with an opening for allowing laser light emitted from the plurality of light sources to pass from the outside to the inside of the housing.
The optical scanning apparatus according to claim 2, wherein the opening is sealed by the lens. According to claim 1, the support portion is provided above the optical path of the laser light emitted from one of the plurality of light sources in the rotation axis direction of the rotating multifaceted mirror. The optical scanning apparatus according to any one of claims 3. Claims 1 to 4 are characterized in that a reflective surface that reflects laser light of the optical member when the optical member is supported by the support portion and a surface of the slope are parallel to each other. The optical scanning apparatus according to any one of the above items. The light according to any one of claims 1 to 5, wherein the optical paths of the respective laser beams emitted from the plurality of light sources have an angular difference in the main scanning direction and the sub-scanning direction. Scanning device. It has a detection means used to determine the timing of emitting laser light from the light source.
The claim is characterized in that the support portion is provided above the optical path of the laser beam emitted from the light source and deflected by the rotating polymorphic mirror toward the detecting means in the rotation axis direction of the rotating multifaceted mirror. The optical scanning apparatus according to any one of claims 1 to 6. The optical member supported by the support portion provided on the slope is an optical member that finally reflects the laser beam among the plurality of optical members that reflect one laser beam, and is close to the rotary multifaceted mirror. The optical scanning apparatus according to any one of claims 1 to 7, wherein the optical member is arranged at a position. Photoreceptor and
The optical scanning apparatus according to any one of claims 1 to 8, which forms a latent image on the photoconductor.
A developing means for developing a latent image formed by the optical scanning device with toner to form a toner image,
A transfer means for transferring the toner image formed by the developing means to the transfer target, and a transfer means.
An image forming apparatus comprising.

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