JP2023083740A - Scanning optical device - Google Patents

Abstract

To prevent a situation where dust near a coupling lens moves toward a polygon mirror and is attached to the polygon mirror.SOLUTION: A scanning optical device 1 comprises: a semiconductor laser 10 that emits light; a coupling lens 20 that converts the light from the semiconductor laser 10 into a beam; a condensing lens 40 that condenses the light from the coupling lens 20 in a sub scanning direction; a deflector 50 that has a polygon mirror 51 deflecting the beam from the condensing lens 40 in a main scanning direction; a scanning optical system Lo that forms the light from the deflector 50 into an image on an image surface; a frame F to which the deflector 50 and the scanning optical system Lo are fixed; and a cover that covers at least a part of the frame F where the deflector 50 is arranged. The frame F has a first wall F1 that has a first opening through which the beam traveling toward the polygon mirror 51 passes. The condensing lens 40 closes the first opening.SELECTED DRAWING: Figure 1

Description

The present invention relates to a scanning optical device comprising a coupling lens and a deflector.

Conventional scanning optical devices include a coupling lens for converting light from a semiconductor laser into a beam, a deflector having a polygon mirror for deflecting the beam from the coupling lens, and a beam deflected by the deflector onto an image plane. A scanning optical system that forms an image and a frame that holds a coupling lens, a deflector, and the scanning optical system are known (see Patent Document 1). In this technique, the frame has a first recess opening in one direction of the rotation axis of the polygon mirror and a second recess opening in the other direction of the rotation axis. The coupling lens and deflector are arranged in the first recess and the scanning optics are arranged in the second recess.

JP 2015-206910 A

However, in the prior art, since the coupling lens and the deflector are in the same space and are not separated, dust near the coupling lens may move toward the polygon mirror and adhere to the polygon mirror.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to prevent dust near a coupling lens from moving toward and adhering to a polygon mirror.

In order to solve the above problems, a scanning optical device according to the present invention includes a semiconductor laser that emits light, a coupling lens that converts the light from the semiconductor laser into a beam, and a sub-scanning beam from the coupling lens. a condenser lens for condensing light in a direction, a deflector having a polygon mirror for deflecting the beam from the condenser lens in the main scanning direction, and a scanning optical system for forming an image of the light from the deflector on an image plane; a frame to which the deflector and the scanning optical system are fixed; and a cover that covers at least a portion of the frame where the deflector is arranged.
The frame has a first wall with a first aperture through which the beam directed to the polygon mirror passes.
The condensing lens closes the first opening.

According to this configuration, the condenser lens closes the first opening through which the beam from the coupling lens to the polygon mirror passes, so that dust in the vicinity of the coupling lens is prevented from moving toward the polygon mirror and adhering to the polygon mirror. can be suppressed.

Moreover, the cover may have a first rib that overlaps the first wall when viewed from the traveling direction of the beam incident on the condenser lens.

According to this configuration, it is possible to improve the sealing performance between the first wall and the cover.

Also, the frame has an aperture plate positioned between the coupling lens and the condensing lens and having an aperture stop through which the beam passes, the condensing lens being located between the first wall and the aperture plate. may be sandwiched between

According to this configuration, by sandwiching the condenser lens between the first wall and the aperture plate, the condenser lens can be brought into close contact with the first wall, and sealing can be improved.

The frame has a second wall having a second aperture through which the beam reflected by the polygon mirror passes, and the scanning lens closest to the polygon mirror in the scanning optical system has the second aperture. You can block it.

With this configuration, it is possible to prevent dust from moving toward the polygon mirror and adhering to the polygon mirror near the scanning optical system.

Also, the scanning optical device may further include a sealing member positioned between the scanning lens and the cover.

With this configuration, the sealing between the scanning lens and the cover can be enhanced.

Further, the cover may have a second rib that overlaps the second wall when viewed from the traveling direction of the beam incident on the scanning lens.

According to this configuration, it is possible to improve the sealing performance between the cover and the second wall.

The scanning optical system is arranged on one side of the polygon mirror in a second direction perpendicular to the first direction along the axis of rotation of the polygon mirror, and perpendicular to the first direction and the second direction. A beam deflected in the main scanning direction is incident, and the scanning optical device further includes a first screw and a second screw for fixing the cover to the frame, and the rotation axis is aligned in the main scanning direction with the It may be located between the first screw and the second screw.

According to this configuration, it is possible to enhance the sealing performance of the portion of the frame where the deflector is arranged.

Further, the semiconductor laser and the coupling lens are provided in plurality, two of the beams emitted from the plurality of coupling lenses are separated in the second direction, and the first screw is the It may be located between the optical paths of the two beams.

Also, the cover may cover the deflector and at least part of the scanning optical system.

According to this configuration, the scanning optical system can also be sealed together with the cover that covers the deflector.

Also, the frame intersects a first base wall on which the deflector is mounted in a first direction along the rotational axis of the polygon mirror, intersects in the first direction, and is relative to the first base wall. and a second base wall positioned at a position shifted to one side in the first direction, wherein the deflector is positioned on the one side in the first direction with respect to the first base wall, The coupling lens may be positioned on the other side in the first direction with respect to the second base wall.

Further, the semiconductor laser includes a first semiconductor laser and a second semiconductor laser arranged at a position spaced apart from the first semiconductor laser in the sub-scanning direction, and the coupling lens is the second semiconductor laser. a first coupling lens for converting light from one semiconductor laser into a beam; and a second coupling lens for converting light from the second semiconductor laser into a beam; The beam from the coupling lens and the beam from the second coupling lens may be condensed in the sub-scanning direction.

According to this configuration, the first aperture through which a plurality of beams pass can be closed with one condensing lens.

Further, the semiconductor laser is arranged at a position spaced apart from the first semiconductor laser in a direction orthogonal to the sub-scanning direction and the advancing direction of the beam incident on the condenser lens from the first semiconductor laser. a third semiconductor laser, wherein the coupling lens comprises a first coupling lens that converts the light from the first semiconductor laser into a beam; and a third coupling lens that converts the light from the third semiconductor laser into a beam. and a coupling lens, wherein the condenser lens may converge the beam from the first coupling lens and the beam from the third coupling lens in the sub-scanning direction.

According to this configuration, the first aperture through which a plurality of beams pass can be closed with one condensing lens.

Further, the condenser lens may have a rib that protrudes in a traveling direction of the beam incident on the condenser lens and contacts the first wall.

According to this configuration, the first opening can be sealed with the condenser lens without bringing the optical surface of the condenser lens into contact with the first wall.

According to the present invention, it is possible to prevent dust near the coupling lens from moving toward the polygon mirror and adhering to the polygon mirror.

3 is a perspective view of the scanning optical device according to one embodiment as viewed from the other side in the first direction; FIG. 4 is a perspective view showing a structure around a coupling lens; FIG. 4 is a perspective view of the scanning optical device as seen from one side in a first direction; FIG. FIG. 2 is a sectional view along IV-IV in FIG. 1; FIG. 2 is a cross-sectional view taken along line VV of FIG. 1; FIG. 10 is a perspective view of the frame viewed from the other side in the first direction; It is the perspective view which looked at the flame|frame from one side of the 1st direction. FIG. 4 is a cross-sectional view showing a structure for attaching a reflecting mirror to a frame; FIG. 4 is an exploded perspective view showing the frame, the first cover, and the second cover; FIG. 4 is a plan view of the frame viewed from one side in the first direction; FIG. 4 is a plan view of the frame to which the first cover is attached, viewed from one side in the first direction; FIG. 5 is a cross-sectional view showing a second rib of the first cover; FIG. 5 is a cross-sectional view showing a sealing member between the first cover and the first scanning lens; It is the perspective view which looked at the 2nd cover from the one side of the 1st direction. FIG. 5 is a cross-sectional view showing the relationship between the first wall and the first rib of the second cover;

As shown in FIGS. 1 to 3, the scanning optical device 1 includes a frame F, an incident optical system Li, a deflector 50, and a scanning optical system Lo. The scanning optical device 1 is applied to an electrophotographic image forming apparatus. In the following description, the direction along the rotation axis X1 of the polygon mirror 51 shown in FIG. 3 is referred to as "first direction". A direction orthogonal to the first direction and in which the polygon mirror 51 and the first scanning lens 60 shown in FIG. 3 are arranged is referred to as a "second direction". Also, a direction orthogonal to the first direction and the second direction is referred to as a "third direction". Note that the third direction corresponds to the main scanning direction in the scanning optical system Lo, and the first direction corresponds to the sub-scanning direction. Also, an arrow indicating each direction in the drawings indicates "one side" in each direction.

As shown in FIG. 2, the incident optical system Li includes four semiconductor lasers 10, four coupling lenses 20, an aperture plate 30, and a condenser lens 40 (see FIG. 1).

The semiconductor laser 10 is a device that emits light. Four semiconductor lasers 10 are provided corresponding to the four photosensitive drums 200 (see FIG. 5) that are scanned and exposed by the scanning optical device 1 . A toner image of a different color is formed on each photosensitive drum 200 .

In this embodiment, the first color is "yellow (Y)," the second color is "magenta (M)," the third color is "cyan (C)," and the fourth color is "black (K)." and In the following description, the name of the part corresponding to the first color may be prefixed with "first" and the part corresponding to the first color may be distinguished by adding "Y" to the end of the reference numeral. Parts corresponding to the second, third, and fourth colors are similarly prefixed with "second," "third," and "fourth," and suffixed with "M , “C”, and “K” may be used for distinction.

The first semiconductor laser 10Y is arranged with a gap in the first direction from the second semiconductor laser 10M. The first semiconductor laser 10Y is located on one side in the first direction with respect to the second semiconductor laser 10M.

The third semiconductor laser 10C is spaced apart from the second semiconductor laser 10M in the second direction. The third semiconductor laser 10C is positioned on the other side in the second direction with respect to the second semiconductor laser 10M. The fourth semiconductor laser 10K is spaced apart from the third semiconductor laser 10C in the first direction and spaced from the first semiconductor laser 10Y in the second direction.

The coupling lens 20 is a lens that converts the light from the semiconductor laser 10 into a beam. Coupling lenses 20Y, 20M, 20C and 20K corresponding to each color are arranged at positions facing corresponding semiconductor lasers 10Y, 10M, 10C and 10K.

As shown in FIG. 1, the diaphragm plate 30 is a part having an aperture diaphragm 31 through which the beam from the coupling lens 20 passes, and is formed integrally with the frame F. As shown in FIG. A diaphragm plate 30 is located between the coupling lens 20 and the condenser lens 40 .

The condenser lens 40 is a lens for condensing the beam from the coupling lens 20 onto the polygon mirror 51 in the sub-scanning direction. The condenser lens 40 is located on the side opposite to the coupling lens 20 with respect to the aperture plate 30 .

As shown in FIG. 3, the deflector 50 has a polygon mirror 51 and a motor 52 . The polygon mirror 51 is a mirror that deflects the beam from the condenser lens 40 in the main scanning direction. The polygon mirror 51 has five mirror surfaces equidistant from the rotation axis X1. A motor 52 is a motor for rotating the polygon mirror 51 . The motor 52 is fixed to the frame F.

The scanning optical system Lo is an optical system that forms an image of the beam deflected by the deflector 50 on the surface of the photosensitive drum 200 as an image plane. The scanning optical system Lo is fixed to the frame F. As shown in FIG. 5, the scanning optical system Lo includes a first scanning optical system LoY for yellow, a second scanning optical system LoM for magenta, a third scanning optical system LoC for cyan, and a scanning optical system LoC for black. and a fourth scanning optical system LoK corresponding to .

The first scanning optical system LoY and the second scanning optical system LoM are arranged on one side of the polygon mirror 51 in the second direction. The third scanning optical system LoC and the fourth scanning optical system LoK are arranged on the other side of the polygon mirror 51 in the second direction. A beam deflected in the main scanning direction by a polygon mirror 51 is incident on each of the scanning optical systems LoY, LoM, LoC, and LoK.

The first scanning optical system LoY has a first scanning lens 60YM, a second scanning lens 70Y, and a reflecting mirror 81Y.

The first scanning lens 60YM is a lens that refracts the beams BY and BM deflected by the deflector 50 in the main scanning direction and forms an image on the image plane. Further, the first scanning lens 60YM has an fθ characteristic that causes the light scanned at a constant angular velocity by the deflector 50 to have a constant velocity on the image plane. The first scanning lens 60YM is the scanning lens closest to the polygon mirror 51 in the first scanning optical system LoY.

The reflecting mirror 81Y is a mirror that reflects the beam BY from the first scanning lens 60YM toward the image plane.
The second scanning lens 70Y is a lens that refracts the beam BY reflected by the reflecting mirror 81Y in the sub-scanning direction and forms an image on the image plane. The second scanning lens 70Y is arranged on one side of the polygon mirror 51 in the first direction. The second scanning lens 70Y is the scanning lens closest to the image plane in the first scanning optical system LoY.

The second scanning optical system LoM has a first scanning lens 60YM, a second scanning lens 70M, a reflecting mirror 81M, and a mirror 82M.

The first scanning lens 60YM is shared with the first scanning optical system LoY. The second scanning lens 70M and reflecting mirror 81M have the same functions as the second scanning lens 70Y and reflecting mirror 81Y of the first scanning optical system LoY. The mirror 82M is a mirror that reflects the beam BM from the first scanning lens 60YM to the reflecting mirror 81M.

The third scanning optical system LoC has a structure that is substantially line-symmetrical to the second scanning optical system LoM with respect to the rotation axis X1 of the polygon mirror 51 . Specifically, the third scanning optical system LoC has a first scanning lens 60CK, a second scanning lens 70C, a reflecting mirror 81C and a mirror 82C that have the same functions as the members of the second scanning optical system LoM.

The fourth scanning optical system LoK has a structure substantially line-symmetrical to the first scanning optical system LoY with respect to the rotation axis X1 of the polygon mirror 51 . Specifically, the fourth scanning optical system LoK has a first scanning lens 60CK, a second scanning lens 70K, and a reflecting mirror 81K that have the same functions as the members of the first scanning optical system LoY.

As shown in FIG. 4, the light emitted from each of the semiconductor lasers 10Y, 10M, 10C and 10K passes through the corresponding coupling lenses 20Y, 20M, 20C and 20K to form beams BY, BM, BC and BK. converted. The beams BY, BM, BC, and BK pass through the corresponding aperture stops 31Y, 31M, 31C, and 31K of the diaphragm plate 30, pass through the condenser lens 40, and are incident on the polygon mirror 51. FIG. The condenser lens 40 is a lens through which the beams BY, BM, BC, and BK commonly pass, and has a cylindrical entrance surface and a plane exit surface.

As shown in FIG. 5, the polygon mirror 51 deflects the beams BY, BM, BC and BK toward the corresponding scanning optics LoY, LoM, LoC and LoK. The beam BY directed toward the first scanning optical system LoY passes through the first scanning lens 60YM, is reflected by the reflecting mirror 81Y, passes through the second scanning lens 70Y, and is emitted toward the image plane on one side in the first direction. be done. The beam BY is emitted from the second scanning lens 70Y at a predetermined angle with respect to the first direction. The beam BY is imaged on the surface of the first photosensitive drum 200Y and scanned in the main scanning direction.

The beam BM traveling toward the second scanning optical system LoM passes through the first scanning lens 60YM, is reflected by the mirror 82M and the reflecting mirror 81M, passes through the second scanning lens 70M, and reaches the image plane on one side in the first direction. emitted towards. The beam BM is emitted from the second scanning lens 70M at a predetermined angle with respect to the first direction. The beam BM is imaged on the surface of the second photosensitive drum 200M and scanned in the main scanning direction. The beams BC and BK are similarly emitted toward the image plane on one side in the first direction by the corresponding scanning optical systems LoC and LoK, and are imaged on the surfaces of the corresponding photosensitive drums 200C and 200K. , are scanned in the main scanning direction.

The frame F is made of resin and integrally formed by molding. The frame F has a first recess CP1 shown in FIG. 7 and a second recess CP2 shown in FIG. The first recess CP1 opens on one side in the first direction. The second recess CP2 opens on the other side in the first direction. As shown in FIG. 5, the deflector 50 and part of the scanning optical system Lo are arranged in the first concave portion CP1. Specifically, the members of the scanning optical system Lo other than the reflecting mirrors 81 are arranged in the first concave portion CP1. As shown in FIG. 2, the coupling lens 20, the aperture plate 30 and the condenser lens 40 (see FIG. 1) are arranged inside the second recess CP2.

As shown in FIGS. 6 and 7, the frame F has a first base wall Fb1 positioned at the bottom of the first recess CP1 and a second base wall Fb2 positioned at the bottom of the second recess CP2.

The first base wall Fb1 and the second base wall Fb2 are walls that intersect in the first direction. Specifically, the first base wall Fb1 and the second base wall Fb2 are walls whose thickness direction is along the first direction. That is, the first base wall Fb1 and the second base wall Fb2 are walls having planes orthogonal to the first direction.

The second base wall Fb2 is located at a position shifted to one side in the first direction with respect to the first base wall Fb1. As shown in FIG. 5, a deflector 50 is attached to the first base wall Fb1. Specifically, a substrate that constitutes the motor 52 is fixed to the first base wall Fb1 with screws from one side in the first direction. In addition, the aforementioned part of the scanning optical system Lo is attached to the first base wall Fb1 on one side in the first direction. Specifically, the first scanning lenses 60YM and 60CK are attached to the first seat surface B1, which is part of the first base wall Fb1, as shown in FIG. The first seat surface B1 is a surface deviated to one side in the first direction from the portion of the first base wall Fb1 to which the deflector 50 is attached. Second scanning lenses 70Y, 70M, 70C, and 70K are attached to a second seating surface B2 that protrudes from the first base wall Fb1 to one side in the first direction. Mirrors 82M and 82C are attached to a third seating surface B3 that protrudes from the first base wall Fb1 to one side in the first direction. A portion of the first base wall Fb1 that overlaps the mirrors 82M and 82C in the first direction is a surface shifted to one side in the first direction from the portion of the first base wall Fb1 to which the deflector 50 is attached. Therefore, the deflector 50 and part of the scanning optical system Lo are positioned on one side in the first direction with respect to the first base wall Fb1. As shown in FIG. 2, the semiconductor laser 10, the coupling lens 20 and the aperture plate 30 are positioned on the other side in the first direction with respect to the second base wall Fb2. Further, as shown in FIG. 1, the condenser lens 40 and the reflecting mirror 81 are also positioned on the other side in the first direction with respect to the second base wall Fb2.

The reflecting mirror 81 is arranged near the first base wall Fb1 and exposed on the other side in the first direction with respect to the first base wall Fb1. In other words, the first base wall Fb1 does not have a portion located on the other side of the reflecting mirror 81 in the first direction. Accordingly, the reflecting mirror 81 is exposed on the other side in the first direction without being hidden by the first base wall Fb1, and can be attached to the frame F from the other side in the first direction.

As shown in FIG. 6, the frame F further has a first wall F1 located between the first recess CP1 and the second recess CP2. The first wall F1 is connected to the first base wall Fb1 and the second base wall Fb2 (see also FIG. 7). The first wall F1 protrudes from the second base wall Fb2 to the other side in the first direction and protrudes from the first base wall Fb1 to one side in the first direction.

The first wall F1 has two first apertures F11, F12 through which the beams BY, BM, BC, BK directed from each aperture stop 31 of the aperture plate 30 to the polygon mirror 51 pass. The first openings F11 and F12 are formed in a slit shape elongated in the first direction, penetrate in the third direction, and open on one side in the first direction (see FIG. 7). The first aperture F11 passes the beams BY and BM. The first aperture F12 passes the beams BC, BK.

As shown in FIG. 1, the condenser lens 40 is arranged to close the first openings F11 and F12 shown in FIG. The condenser lens 40 is sandwiched between the first wall F1 and the aperture plate 30. As shown in FIG. As shown in FIG. 15, the condenser lens 40 has ribs 40A that protrude from the exit surface to one side in the third direction, and the ribs 40A are in contact with the first wall F1. The condenser lens 40 also has a rib 40B projecting from the entrance surface to the other side in the third direction, and the rib 40B is in contact with the aperture plate 30 . Specifically, each end in the second direction of the rib 40B is in contact with the aperture plate 30 (see FIG. 1). The ribs 40A and 40B are configured to surround the exit surface and the entrance surface, which are the optical surfaces of the condenser lens 40. As shown in FIG. As a result, the condenser lens 40 can block the first apertures F11 and F12 without bringing the optical surface of the condenser lens 40 into direct contact with the first wall F1 and the aperture plate 30 .

As shown in FIGS. 3 and 7, the frame F further has two second walls F2 positioned on either side of the polygon mirror 51 (see FIG. 3) in the second direction. A second wall F2 on one side in the second direction has a second opening F21 through which the beams BY and BM reflected by the polygon mirror 51 pass. A second wall F2 on the other side in the second direction has a second opening F22 through which the beams BC and BK reflected by the polygon mirror 51 pass. Each of the second openings F21 and F22 penetrates in the second direction and opens on one side in the first direction.

Each second wall F2 protrudes from the first base wall Fb1 to one side in the first direction. Each 2nd wall F2 is connected to the 1st wall F1 and the 1st side wall F41 mentioned later. Thus, the first base wall Fb1, the first wall F1, the second walls F2, and the first side walls F41 form an accommodation recess CP3 for accommodating the polygon mirror 51. As shown in FIG.

The first scanning lens 60YM is arranged so as to block part of the second opening F21. The first scanning lens 60CK is arranged so as to block part of the second opening F22.

The frame F further has a first side wall F41, a second side wall F42, a third side wall F43 and a fourth side wall F44 forming a substantially rectangular frame surrounding the recesses CP1 and CP2.

The first side wall F41 is located on the side opposite to the semiconductor laser 10 with respect to the deflector 50 . The first side wall F41 protrudes from the first base wall Fb1 to one side in the first direction.

The second side wall F42 is located on the opposite side of the deflector 50 from the first side wall F41. Specifically, the second side wall F42 is located on the side opposite to the deflector 50 with respect to the coupling lens 20 . The second side wall F42 protrudes from the second base wall Fb2 to the other side in the first direction.

The third side wall F43 is located on the side opposite to the deflector 50 with respect to the first scanning lens 60YM. The third side wall F43 is connected to one end in the second direction of the first side wall F41, the first base wall Fb1, the second base wall Fb2, and the second side wall F42. A portion of the third side wall F43 protrudes from the first base wall Fb1 to one side in the first direction, and the other portion protrudes from the second base wall Fb2 to the other side in the first direction.

The fourth side wall F44 is located on the side opposite to the deflector 50 with respect to the first scanning lens 60CK. The fourth side wall F44 is connected to ends of the first side wall F41, the first base wall Fb1, the second base wall Fb2, and the second side wall F42 on the other side in the second direction. A portion of the fourth side wall F44 protrudes from the first base wall Fb1 to one side in the first direction, and the other portion protrudes from the second base wall Fb2 to the other side in the first direction.

As shown in FIG. 8, the scanning optical device 1 further has a support member Fs that can be attached to and detached from the frame F having the above-described first recess CP1 and second recess CP2. The support member Fs is a member that supports the reflecting mirror 81 . The support member Fs has a bearing surface FsZ that supports the reflecting mirror 81 and is adjustable in angle. The seat surface FsZ has a spherical protrusion Fs1 capable of tiltably supporting the reflecting mirror 81 . The protrusion Fs1 protrudes toward the reflecting mirror 81 and becomes a fulcrum when the reflecting mirror 81 is adjusted in its orientation by coming into contact with the reflecting mirror 81 . The orientation of the reflecting mirror 81 with respect to the seat surface FsZ is fixed by the photocurable resin P. As shown in FIG. The photocurable resin P can be, for example, an ultraviolet curable resin. The reflecting mirror 81 and the support member Fs fixed by the photocurable resin P are attached to the frame F by U-shaped leaf springs SP.

One supporting member Fs and one plate spring SP are arranged at both ends of the reflecting mirror 81 in the longitudinal direction for one reflecting mirror 81 . A pair of supporting members Fs and a pair of leaf springs SP corresponding to one reflecting mirror 81 are provided for each of the four reflecting mirrors 81 .

The frame F has a support surface Fm1 that supports the support member Fs. The support surface Fm1 is arranged at a position corresponding to each longitudinal end of the four reflecting mirrors 81 (see FIG. 6).

When the reflecting mirror 81 is attached to the frame F, the photocurable resin P is applied to both sides of the protrusion Fs1 of the support member Fs, and the support member Fs is attached to the support surface Fm1. After that, the first reflecting mirror 81 is brought into contact with the protrusion Fs1 of the support member Fs. At this time, the photocurable resin P is arranged in contact with both the supporting member Fs and the first reflecting mirror 81 . After that, the plate spring SP is attached, and the first reflecting mirror 81 is pressed toward the frame F together with the support member Fs. Next, while light is being emitted from the semiconductor laser 10, the angle of the first reflecting mirror 81 is changed while monitoring the position of the beam on the image plane by tilting the first reflecting mirror 81 with the projection Fs1 as a starting point. adjust. When adjusting the angle, an arm (not shown) is pressed against the first reflecting mirror 81 to move the first reflecting mirror 81 . After the angle adjustment is completed, the photocurable resin P is exposed to light, thereby fixing the first reflecting mirror 81 to the support member Fs.

As shown in FIG. 2, the scanning optical device 1 further includes a first laser holder H11, a second laser holder H12, a first lens holder H21, and a second lens holder H22.

The first laser holder H11 is an L-shaped member in cross section that holds the first semiconductor laser 10Y, the second semiconductor laser 10M, and the first coupling lens 20Y. The first coupling lens 20Y is fixed to the first laser holder H11 with photocurable resin. The first coupling lens 20Y can be attached to the first laser holder H11 from the other side in the first direction. The first laser holder H11 is fixed to the frame F. Note that the second laser holder H12 differs from the first laser holder H11 only in the object to be held, and is otherwise configured in the same manner as the first laser holder H11, so description thereof will be omitted.

The first lens holder H21 is a member that holds the second coupling lens 20M at a position aligned in the first direction with respect to the first coupling lens 20Y. The first lens holder H21 has a tubular portion in which the second coupling lens 20M is fitted. The first lens holder H21 is fixed to the first laser holder H11 with a photocurable resin. The first lens holder H21 can be attached to the first laser holder H11 from the other side in the first direction. The second lens holder H22 differs from the first lens holder H21 in that it only holds and fixes to the second laser holder H12, and is otherwise configured in the same manner as the first lens holder H21. Therefore, the description is omitted.

When attaching the coupling lens 20 to the frame, the laser holders H11 and H12 are fixed to the frame F first. After that, a photocurable resin is applied to the first coupling lens 20Y or the first laser holder H11, and the position of the first coupling lens 20Y is adjusted with respect to the first semiconductor laser 10Y. After adjusting the position, the first coupling lens 20Y is fixed to the first laser holder H11 by applying light to the photocurable resin. The fourth coupling lens 20K is also fixed to the second laser holder H12 in the same manner as the first coupling lens 20Y.

After that, a photocurable resin is applied to the first lens holder H21 or the first laser holder H11 holding the second coupling lens 20M, and the position of the second coupling lens 20M is adjusted with respect to the second semiconductor laser 10M. do. After adjusting the position, the first lens holder H21 is fixed to the first laser holder H11 by exposing the photocurable resin to light. The third coupling lens 20C is also fixed to the second laser holder H12 via the second lens holder H22 in the same manner as the second coupling lens 20M.

The scanning optical device 1 further comprises a cover C, as shown in FIG. The cover C has a first cover C1 and a second cover C2.

The first cover C1 is a cover that covers the deflector 50 and the first base wall Fb1 from one side in the first direction. Specifically, the first cover C1 covers the first recess CP1.

The second cover C2 is a cover that covers the coupling lens 20 and the second base wall Fb2 from the other side in the first direction. Specifically, the second cover C2 covers the second recess CP2.

The scanning optical device 1 further comprises a first screw N1, a second screw N2 and two third screws N3. The first screw N1 and the second screw N2 are screws for fixing the first cover C1 to the frame F. As shown in FIG. Each third screw N3 is a screw for fixing the second cover C2 to the frame F. As shown in FIG.

As shown in FIG. 10, the frame F has a first boss F51 to which the first screw N1 is fastened, and a second boss F52 to which the second screw N2 is fastened. The first boss F51, the rotation axis X1 of the polygon mirror 51, and the second boss F52 are arranged in the third direction. Specifically, the first boss F51 and the second boss F52 are positioned on a straight line LN extending in the third direction and passing through the rotation axis X1. The rotation axis X1 is located between the first boss F51 and the second boss F52 in the third direction. Also, the first boss F51 is positioned between the optical paths of two beams separated in the second direction, for example, the beams BY and BK.

Therefore, as shown in FIG. 11, when the first cover C1 is attached to the frame F, the rotation axis X1 is located between the first screw N1 and the second screw N2 in the third direction. Also, the first screw N1 and the second screw N2 are positioned on the straight line LN described above. Furthermore, the first screw N1 is positioned between the optical paths of the two beams BY and BK that are separated in the second direction.

As shown in FIG. 12, the first cover C1 has two second ribs R21 and R22. Each of the second ribs R21 and R22 overlaps the second wall F2 when viewed from the traveling direction of the beam incident on the first scanning lens 60YM (see FIG. 13), more specifically from the second direction. Each second rib R21, R22 extends in the third direction. Each of the second ribs R21 and R22 has a distance in the second direction from the second wall F2 smaller than the thickness of the second wall F2. The two second ribs R21 and R22 sandwich the second wall F2 in the second direction. Of the two, the second rib R21 on the side farther from the polygon mirror 51 protrudes toward the first base wall Fb1 than the second rib R22 on the closer side. The two second ribs R21 and R22 are similarly provided on the second wall F2 on the other side of the polygon mirror 51 in the second direction.

As shown in FIG. 13, the scanning optical device 1 further includes a seal member SL positioned between the first scanning lens 60YM and the second rib R21 of the first cover C1. The seal member SL is made of an elastic member such as sponge. The sealing member SL closes the second opening F21 (see FIG. 3) of the second wall F2 together with the first scanning lens 60YM. The sealing member SL is similarly provided for the first scanning lens 60CK located on the other side of the polygon mirror 51 in the second direction.

As shown in FIG. 14, the second cover C2 has a first rib R1 and two third ribs R3. The first rib R1 extends in the second direction. The two third ribs R3 are arranged side by side in the second direction with a gap therebetween in the second direction central portion of the first rib R1. Each third rib R3 protrudes further toward the second base wall Fb2 (see FIG. 15) than the first rib R1.

As shown in FIG. 15, the first rib R1 overlaps the first wall F1 when viewed from the traveling direction of the beam incident on the condenser lens 40, specifically from the third direction. The distance between the first rib R1 and the first wall F1 in the third direction is equal to or less than the thickness of the first wall F1.

As shown in FIG. 4, the third rib R3 overlaps the first wall F1 when viewed from the third direction. The distance in the third direction between the third rib R3 and the first wall F1 is smaller than the thickness of the first wall F1. The third rib R3 and the frame F sandwich the condensing lens 40 therebetween.

Next, operations for adjusting the positions and orientations of the members of the scanning optical device 1 will be described.
As shown in FIGS. 1 and 2, when adjusting the position of the coupling lens 20, a jig for holding the coupling lens 20 or the lens holders H21 and H22 is moved from the other side in the first direction into the second concave portion. Put in CP2. Therefore, the device for position adjustment is arranged on the other side of the frame F in the first direction.

Further, when performing an inspection for detecting the beam incident on the polygon mirror 51, the device for inspection is put into the first concave portion CP1 from one side in the first direction. Therefore, the device for inspection is arranged on one side of the frame F in the first direction.

When adjusting the angle of the reflecting mirror 81, the jig holding the reflecting mirror 81 is brought into contact with the reflecting mirror 81 from the other side in the first direction. Therefore, the device for angle adjustment is arranged on the other side of the frame F in the first direction. At that time, the beam is detected by an inspection device arranged on one side of the second scanning lens 70 in the first direction. A device for detecting the beam is arranged on one side of the frame F in the first direction, and a device for adjusting the position of the coupling lens 20 and a device for adjusting the angle of the reflecting mirror 81 are arranged on the other side of the frame F in the first direction. It can be placed on the side. Since the device for detection and the device for adjustment can be arranged on opposite sides of the frame F, restrictions on the structure of manufacturing equipment can be relaxed. Further, this makes it possible to continuously adjust the position of the coupling lens 20 and the angle of the reflection mirror 81 while fixing the frame F to the manufacturing equipment.

According to the above, the following effects can be obtained in this embodiment.
A device for adjusting the position of the coupling lens 20 can be arranged on the other side of the frame F in the first direction, and a device for detecting light incident on the polygon mirror 51 can be arranged on one side of the frame F in the first direction. Since it can be placed in the space, restrictions on the structure of the equipment can be relaxed.

By arranging the deflector 50 and part of the scanning optical system Lo on the same side with respect to the first base wall Fb1, the attachment direction of the deflector 50 and part of the scanning optical system Lo becomes the same direction. The optical system Lo can be arranged with high accuracy.

Since the beam from the scanning optical system Lo is emitted to one side in the first direction, the beam emitted from the scanning optical system Lo can be measured from the opposite side of the device for adjusting the position of the coupling lens 20. .

Since the reflecting mirror 81 is exposed on the other side in the first direction with respect to the first base wall Fb1, the coupling lens 20 and the reflecting mirror 81 requiring adjustment can be adjusted from the same side.

Since the first cover C1 that covers the deflector 50 and the first base wall Fb1 from one side in the first direction is provided, the first cover C1 can prevent dust from adhering to the deflector 50 .

Since the second cover C2 is provided to cover the coupling lens 20 and the second base wall Fb2 from the other side in the first direction, the second cover C2 can prevent dust from adhering to the coupling lens 20.

Since the rotation axis X1 of the polygon mirror 51 is positioned between the first screw N1 and the second screw N2 in the main scanning direction, the sealing of the portion of the frame F where the deflector 50 is arranged can be enhanced.

Since the first apertures F11 and F12 through which the beams from the coupling lens 20 to the polygon mirror 51 pass are blocked by the condenser lens 40, dust near the coupling lens 20 moves toward the polygon mirror 51 and falls on the polygon mirror 51. Adhesion can be suppressed.

Since the second cover C2 has the first rib R1 that overlaps the first wall F1 when viewed from the third direction, it is possible to improve the airtightness between the first wall F1 and the second cover C2.

Since the condenser lens 40 is sandwiched between the first wall F1 and the aperture plate 30, the condenser lens 40 can be brought into close contact with the first wall F1, thereby improving sealing.

Since the second apertures F21 and F22 through which the beams reflected by the polygon mirror 51 pass are blocked by the first scanning lenses 60YM and 60CK, dust in the vicinity of the scanning optical system Lo moves toward the polygon mirror 51 and hits the polygon mirror 51. Adhesion can be suppressed.

Since the sealing member SL is provided between the first scanning lenses 60YM, 60CK and the first cover C1, the sealing between the first scanning lenses 60YM, 60CK and the first cover C1 can be improved.

Since the first cover C1 has the second ribs R21 and R22 that overlap the second wall F2 when viewed from the second direction, it is possible to enhance the airtightness between the first cover C1 and the second wall F2.

Also, the cover may cover the deflector and at least part of the scanning optical system.

Since the first cover C1 covers the deflector 50 and part of the scanning optical system Lo, the first cover C1 can seal the deflector 50 and part of the scanning optical system Lo together.

The present invention is not limited to the above-described embodiments, and can be used in various forms as exemplified below.

Although a part of the scanning optical system Lo is attached to one side of the first base wall Fb1 in the first direction in the above embodiment, the present invention is not limited to this. For example, the entire scanning optical system may be mounted on one side of the first base wall in the first direction.

In the above embodiment, the frame F is provided with the first sidewall F41, the second sidewall F42, the third sidewall F43, and the fourth sidewall F44, but the invention is not limited to this, and at least one of the four sidewalls is , may be provided on the cover.

The cover may cover at least the portion of the frame where the deflector is arranged. For example, a cover that covers the deflector and a cover that covers a part of the scanning optical system may be separate. Also, the cover may cover the entire scanning optical system. For example, when the entire scanning optical system is accommodated in the first recess, the cover may cover the entire scanning optical system.

The numbers of the first ribs and the second ribs are not limited to those in the above embodiment, and may be any number. Alternatively, two first ribs may be provided and the first wall may be sandwiched between the two first ribs.

In the above embodiment, the support member Fs having the seat surface FsZ is made of a member different from the frame F, but the seat surface FsZ may be provided integrally with the frame F.

The semiconductor laser 10 may be configured to have a plurality of light emitting points. As a result, a plurality of beams emitted from the semiconductor laser 10 are converted into a plurality of beams by one coupling lens 20, and the plurality of beams are imaged on the surface of the photosensitive drum 200 by the corresponding scanning optical system Lo. may When configured in this manner, the beams BY, BM, BC, and BK of the above embodiment each include a plurality of beams.

Although the scanning optical device applied to the color image forming apparatus is exemplified in the above embodiment, the scanning optical device may be applied to a monochrome image forming apparatus that scans only one beam.

Each element described in the above embodiment and modifications may be implemented in any combination.

REFERENCE SIGNS LIST 1 scanning optical device 10 semiconductor laser 20 coupling lens 40 condenser lens 50 deflector 51 polygon mirror C cover F frame F1 first wall F11 first aperture F12 first aperture Lo scanning optical system

Claims (13)

a semiconductor laser that emits light;
a coupling lens for converting light from the semiconductor laser into a beam;
a condenser lens for condensing the beam from the coupling lens in a sub-scanning direction;
a deflector having a polygon mirror that deflects the beam from the condenser lens in a main scanning direction;
a scanning optical system that forms an image of the light from the deflector on an image plane;
a frame to which the deflector and the scanning optical system are fixed;
a cover that covers at least a portion of the frame where the deflector is arranged;
the frame has a first wall with a first aperture through which a beam directed to the polygon mirror passes;
The scanning optical device, wherein the condensing lens closes the first opening. The cover is
2. A scanning optical apparatus according to claim 1, further comprising a first rib that overlaps with said first wall when viewed from a direction in which a beam incident on said condenser lens travels. The frame is
a diaphragm plate positioned between the coupling lens and the condenser lens and having an aperture diaphragm through which the beam passes;
3. A scanning optical device according to claim 1, wherein said condenser lens is sandwiched between said first wall and said aperture plate. the frame has a second wall with a second aperture through which the beam reflected by the polygon mirror passes;
4. The scanning optical apparatus according to claim 1, wherein the scanning lens closest to the polygon mirror in the scanning optical system closes the second aperture. 5. The scanning optical device of claim 4, further comprising a sealing member positioned between said scanning lens and said cover. The cover is
6. A scanning optical device according to claim 4, further comprising a second rib that overlaps with the second wall when viewed from the direction of travel of the beam incident on the scanning lens. The scanning optical system is arranged on one side of the polygon mirror in a second direction perpendicular to the first direction along the axis of rotation of the polygon mirror, and the scanning optical system is arranged on one side of the polygon mirror and is perpendicular to the first direction and the second direction. A beam deflected in the scanning direction is incident,
the scanning optics further comprising a first screw and a second screw securing the cover to the frame;
7. The scanning optical device according to claim 1, wherein the rotation axis is positioned between the first screw and the second screw in the main scanning direction. Having a plurality of the semiconductor lasers and the coupling lenses,
two of the beams emitted from the plurality of coupling lenses are separated in the second direction;
8. The scanning optical apparatus of claim 7, wherein said first screw is positioned between the optical paths of said two beams. 9. The scanning optical device according to claim 1, wherein the cover covers the deflector and at least part of the scanning optical system. The frame is
a first base wall that intersects a first direction along the axis of rotation of the polygon mirror and on which the deflector is mounted;
a second base wall that intersects the first direction and is located at a position shifted to one side in the first direction with respect to the first base wall;
the deflector is positioned on one side in the first direction with respect to the first base wall;
10. The scanning optical device according to claim 1, wherein the coupling lens is positioned on the other side in the first direction with respect to the second base wall. the semiconductor laser includes a first semiconductor laser and a second semiconductor laser spaced from the first semiconductor laser in the sub-scanning direction;
the coupling lens includes a first coupling lens that converts light from the first semiconductor laser into a beam, and a second coupling lens that converts light from the second semiconductor laser into a beam;
11. Any of claims 1 to 10, wherein the condenser lens converges the beam from the first coupling lens and the beam from the second coupling lens in the sub-scanning direction. A scanning optical device according to any one of the preceding claims. The semiconductor laser is arranged at a position spaced apart from the first semiconductor laser in a direction orthogonal to the sub-scanning direction and the traveling direction of the beam incident on the condenser lens from the first semiconductor laser. a semiconductor laser;
the coupling lens includes a first coupling lens that converts light from the first semiconductor laser into a beam, and a third coupling lens that converts light from the third semiconductor laser into a beam;
12. The condensing lens converges the beam from the first coupling lens and the beam from the third coupling lens in the sub-scanning direction. A scanning optical device according to any one of the preceding claims. 13. The condensing lens according to any one of claims 1 to 12, wherein the condensing lens has a rib that protrudes in a traveling direction of the beam incident on the condensing lens and contacts the first wall. scanning optics.

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