CN116224576A - Scanning optical device and method for manufacturing scanning optical device - Google Patents

Abstract

The invention discloses a scanning optical device and a method for manufacturing the same, which can mount a plurality of coupling lenses from the same direction to restrain the complexity of manufacturing process. The scanning optical device includes: a first coupling lens (20Y) and a second coupling lens (20M) for converting light from a semiconductor laser into a light beam, a polygon mirror for deflecting the light beam from the coupling lens (20), a first holding member (a first laser holder (H11)) having a seat surface (Hf) for fixing the first coupling lens by a photo-setting resin (P), and a second holding member (a first lens holder (H2A)) for holding the second coupling lens. The second semiconductor lasers (10M) are arranged in the direction of the rotation axis of the polygon mirror with respect to the first semiconductor lasers (10Y). The second holding member holds the second coupling lenses at positions aligned in the rotation axis direction with respect to the first coupling lenses and is fixed to the first holding member by a photo-setting resin.

Description

Scanning optical device and method for manufacturing scanning optical device

Technical Field

The present invention relates to a scanning optical device including a plurality of semiconductor lasers and a coupling lens, and a method for manufacturing the scanning optical device.

Background

Conventionally, as a scanning optical device, a scanning optical device including a holder having two seating surfaces to which two coupling lenses are attached, in which two semiconductor lasers are pressed, has been known (see patent document 1). Specifically, in this technique, the holder has a wall located between two coupling lenses, and one surface and the other surface of the wall are each a seat surface for mounting each coupling lens.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 2007-144952

Technical problem to be solved by the invention

However, in the prior art, after one coupling lens is mounted on the seat surface on one side of the wall from one side, the other coupling lens is required to be mounted on the seat surface on the other side from the direction opposite to the mounting direction of the one coupling lens, which has a problem of complicating the manufacturing process.

Disclosure of Invention

Accordingly, an object of the present invention is to prevent a manufacturing process from being complicated by enabling a plurality of coupling lenses to be mounted from the same direction.

Technical means for solving the technical problems

In order to solve the above-described problems, a scanning optical device according to the present invention includes: a first semiconductor laser that emits light; a second semiconductor laser that emits light; a first coupling lens that converts light from the first semiconductor laser into a light beam; a second coupling lens that converts light from the second semiconductor laser into a light beam; a polygon mirror that deflects the light beam from the first coupling lens and the light beam from the second coupling lens; a first holding member that holds the first coupling lens and has a seating surface to which the first coupling lens is fixed by a photo-setting resin; and a second holding member that holds the second coupling lens.

The second semiconductor lasers are arranged in the rotation axis direction of the polygon mirror with respect to the first semiconductor lasers.

The second holding member holds the second coupling lenses at positions aligned in the rotation axis direction with respect to the first coupling lenses, and is fixed to the first holding member by a photo-setting resin.

According to this configuration, after the first coupling lens is mounted on the seating surface of the first holding member from the predetermined direction, the second holding member holding the second coupling lens can be mounted on the first holding member from the predetermined direction, whereby a plurality of coupling lenses can be mounted from the same direction, and the complexity of the manufacturing process can be suppressed.

The seating surface may be a plane orthogonal to the rotation axis direction.

The second holding member may include: a lens mounting portion to which the second coupling lens is mounted; and a leg portion extending from the lens mounting portion toward the seating surface, the leg portion being fixed to the seating surface by a photo-setting resin.

According to this configuration, since the second holding member has the leg portion extending from the lens mounting portion, interference between the lens mounting portion and the first coupling lens can be suppressed.

The leg portion may have: a first foot; and a second leg portion that is separated from the first leg portion in a direction orthogonal to the rotation axis direction and the optical axis direction of the first semiconductor laser, and through which light that has traveled from the first semiconductor laser to the first coupling lens passes between the first leg portion and the second leg portion.

According to this structure, since the two legs of the second holding member are fixed to the seating surface, the second coupling lens can be stably held by the second holding member.

The second holding member may be made of a material that is transparent to light for curing the photocurable resin.

According to this configuration, when the second holding member is fixed to the first holding member, light can be passed through the second holding member to cure the photocurable resin, and thus the second holding member can be easily fixed to the first holding member.

In addition, the first holding member may include: a first portion having the seating surface; and a second portion extending from the first portion toward the rotation axis direction and holding the first semiconductor laser and the second semiconductor laser.

According to this configuration, since the portion holding the first semiconductor laser is integrated with the mount surface to which the first coupling lens is fixed, the positional accuracy of the first coupling lens with respect to the first semiconductor laser can be improved.

In addition, the first holding member and the second holding member may be made of resin.

According to this configuration, the linear expansion coefficients of the first holding member and the second holding member can be unified, and therefore, misalignment between the first coupling lens and the second coupling lens can be suppressed when the respective holding members are linearly expanded.

The method for manufacturing a scanning optical device according to the present invention is a method for manufacturing a scanning optical device including: a first semiconductor laser that emits light; a second semiconductor laser that emits light; a first coupling lens that converts light from the first semiconductor laser into a light beam; a second coupling lens that converts light from the second semiconductor laser into a light beam; a polygon mirror that deflects the light beam from the first coupling lens and the light beam from the second coupling lens; a first holding member that holds the first coupling lens and has a seating surface to which the first coupling lens is fixed; and a second holding member that holds the second coupling lens, the second semiconductor laser being arranged in a rotation axis direction of the polygon mirror with respect to the first semiconductor laser, the second holding member holding the second coupling lens in a position arranged in the rotation axis direction with respect to the first coupling lens.

The method for manufacturing the scanning optical device comprises the following steps: a first bonding step of adjusting a position of the first coupling lens with respect to the first semiconductor laser and bonding and fixing the first coupling lens to the seating surface of the first holding member; and a second bonding step of adjusting a position of the second coupling lens with respect to the second semiconductor laser and bonding and fixing the second holding member to which the second coupling lens is attached to the first holding member.

According to this manufacturing method, after the first coupling lens is mounted on the seating surface of the first holding member from the predetermined direction, the second holding member holding the second coupling lens can be mounted on the first holding member from the predetermined direction, so that a plurality of coupling lenses can be mounted from the same direction, and the complexity of the manufacturing process can be suppressed.

In the first bonding step, a photo-setting resin may be disposed between the first coupling lens and the seat surface, the first coupling lens may be bonded and fixed to the seat surface by applying light to the photo-setting resin after the position of the first coupling lens is adjusted, and the second bonding step, a photo-setting resin may be disposed between the second holding member and the first holding member, and the second holding member may be bonded and fixed to the first holding member by applying light to the photo-setting resin after the position of the second coupling lens is adjusted.

Further, the position of the first coupling lens may be adjusted using a jig that clamps the first coupling lens in an orthogonal direction orthogonal to the optical axis direction of the first semiconductor laser and the rotation axis direction.

Further, the jig may clamp the second holding member from the orthogonal direction to adjust the position of the second coupling lens.

As another aspect of the scanning optical device for solving the above-described problems, the scanning optical device includes: a first semiconductor laser that emits light; a second semiconductor laser that emits light; a first coupling lens that converts light from the first semiconductor laser into a light beam; a second coupling lens that converts light from the second semiconductor laser into a light beam; a deflector having a polygon mirror that deflects the light beam from the first coupling lens and the light beam from the second coupling lens in directions; a frame to which the deflector is fixed; a first holding member that holds the first coupling lens and has a first seating surface to which the first coupling lens is fixed by a photo-setting resin; and a second holding member that holds the second coupling lens and has a second seating surface to which the second coupling lens is fixed by a photo-setting resin.

The second semiconductor lasers are arranged in the rotation axis direction of the polygon mirror with respect to the first semiconductor lasers.

The second holding member holds the second coupling lenses at positions aligned in the rotation axis direction with respect to the first coupling lenses, and is fixed to the frame.

According to this configuration, the first coupling lens is mounted on the seating surface of the first holding member from a predetermined direction, the second holding member is mounted on the frame, and then the second coupling lens can be mounted on the second holding member from a predetermined direction.

Further, the first seat surface and the second seat surface may be planes orthogonal to the rotation axis direction.

The second holding member may include: a base having the second seating surface; and a leg portion extending from the base portion toward a side opposite to the second seating surface, the leg portion being fixed to the frame.

According to this structure, the second holding member has the leg portion extending from the base portion, so that interference between the base portion and the first coupling lens can be suppressed.

The leg portion may have: a first foot; and a second leg portion that is separated from the first leg portion in an orthogonal direction orthogonal to an optical axis direction of the first semiconductor laser and the rotation axis direction, and that passes between the first leg portion and the second leg portion, light that has traveled from the first semiconductor laser to the first coupling lens.

According to this structure, the two legs of the second holding member are fixed to the frame, so the second coupling lens can be stably held by the second holding member.

In addition, the first holding member may include: a first portion having the first seating surface; and a second portion extending from the first portion toward the rotation axis direction and holding the first semiconductor laser and the second semiconductor laser.

According to this configuration, since the portion holding the first semiconductor laser is integrated with the first seating surface to which the first coupling lens is fixed, the positional accuracy of the first coupling lens with respect to the first semiconductor laser can be improved.

The frame may further include: a first positioning surface that positions the first holding member in a first prescribed direction; and a second regulating portion that positions the second holding member in the first predetermined direction, the second regulating portion intersecting a first plane including the first positioning surface.

According to this configuration, the second regulating portion is disposed at substantially the same position as the first positioning surface in the first predetermined direction, so that the influence of thermal expansion of each holding member in the first predetermined direction can be reduced.

The frame may further include: a first regulating portion that positions the first holding member in a second predetermined direction; and a second positioning surface that positions the second holding member in the second predetermined direction, the first restricting portion intersecting a second plane including the second positioning surface.

According to this configuration, the first regulating portion is disposed at substantially the same position as the second positioning surface in the second predetermined direction, so that the influence of thermal expansion of each holding member in the second predetermined direction can be reduced.

The second holding member may be fixed to the frame by a screw.

The scanning optical device may further include: a third semiconductor laser arranged with the second semiconductor laser in an orthogonal direction orthogonal to an optical axis direction of the first semiconductor laser and the rotation axis direction; a fourth semiconductor laser arranged with the first semiconductor laser in the orthogonal direction and with the third semiconductor laser in the rotation axis direction; a third coupling lens that converts light from the third semiconductor laser into a light beam; and a fourth coupling lens that converts light from the fourth semiconductor laser into a light beam, the third coupling lens being fixed to the second seating surface by a photo-setting resin.

According to this configuration, the second coupling lens and the third coupling lens are fixed to the second seating surface of the second holding member, and therefore, the number of components can be reduced as compared with a configuration in which the third coupling lens is fixed to a component different from the second holding member, for example.

In another aspect of the method for manufacturing a scanning optical device, the scanning optical device includes: a first semiconductor laser that emits light; a second semiconductor laser that emits light; a first coupling lens that converts light from the first semiconductor laser into a light beam; a second coupling lens that converts light from the second semiconductor laser into a light beam; a deflector having a polygon mirror that deflects the light beam from the first coupling lens and the light beam from the second coupling lens in directions; a frame to which the deflector is fixed; a first holding member that holds the first coupling lens and has a first seating surface to which the first coupling lens is fixed by a photo-setting resin; and a second holding member that holds the second coupling lens and has a second seating surface to which the second coupling lens is fixed, the second semiconductor lasers being aligned in a rotation axis direction of the polygon mirror with respect to the first semiconductor lasers, the second holding member holding the second coupling lens in a position aligned in the rotation axis direction with respect to the first coupling lens and being fixed to the frame.

The method for manufacturing the scanning optical device comprises the following steps: a first bonding step of adjusting a position of the first coupling lens with respect to the first semiconductor laser and bonding and fixing the first coupling lens to the first seating surface of the first holding member; an attaching step of attaching the second holding member to the frame; and a second bonding step of adjusting a position of the second coupling lens with respect to the second semiconductor laser and bonding and fixing the second coupling lens to the second seating surface of the second holding member.

According to this manufacturing method, since the first coupling lens is mounted on the seat surface of the first holding member from the predetermined direction, the second holding member is mounted on the frame, and then the second coupling lens can be mounted on the second holding member from the predetermined direction, a plurality of coupling lenses can be mounted from the same direction, and the complexity of the manufacturing process can be suppressed.

In the first bonding step, a photo-setting resin may be disposed between the first coupling lens and the first seat surface, the first coupling lens may be bonded and fixed to the first seat surface by applying light to the photo-setting resin after the position of the first coupling lens is adjusted, and the second coupling lens may be bonded and fixed to the second seat surface by applying light to the photo-setting resin after the position of the second coupling lens is adjusted.

Further, the position of the first coupling lens may be adjusted using a jig that clamps the first coupling lens in an orthogonal direction orthogonal to the optical axis direction of the first semiconductor laser and the rotation axis direction.

Further, the jig may clamp the second coupling lens from the orthogonal direction to adjust the position of the second coupling lens.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, since a plurality of coupling lenses can be mounted from the same direction, the complexity of the manufacturing process can be suppressed.

Drawings

Fig. 1 is a perspective view of a scanning optical device according to an embodiment, viewed from the other side in the first direction.

Fig. 2 is a perspective view showing a structure around the coupling lens.

Fig. 3 is a perspective view of the scanning optical device viewed from one side in the first direction.

Fig. 4 is a cross-sectional view of IV-IV of fig. 1.

Fig. 5 is a V-V cross-sectional view of fig. 1.

Fig. 6 (a) is a perspective view showing the first laser holder, (b) is a rear view of the first laser holder as seen from the other side in the third direction, and (c) is a side view showing a part of the first laser holder in a cut-away manner.

Fig. 7 is an exploded perspective view showing the relationship of the frame and the laser holder.

Fig. 8 (a) is a view of the frame from the other side in the third direction, and (b) is a cross-sectional view showing a hole forming the aperture stop.

Fig. 9 (a) is a perspective view showing the first lens holder, and (b) is a view showing the relationship between light from the first semiconductor laser and the first lens holder.

Fig. 10 (a) to (d) are diagrams showing a method of attaching the coupling lens to the frame.

Fig. 11 is a perspective view showing a relationship between an insert and a frame.

Fig. 12 is a cross-sectional view showing a state after the frame is injection molded by a mold.

Fig. 13 is a perspective view showing a configuration around a coupling lens in the scanning optical device according to the modification.

Fig. 14 (a) is a perspective view of the lens holder viewed from one side in the third direction, and (b) is a perspective view viewed from the other side in the third direction.

Fig. 15 is a diagram showing a relationship between the second boss and the first positioning surface.

Fig. 16 is a diagram showing a relationship between the first boss and the second positioning surface.

Fig. 17 (a) to (c) are diagrams showing a method of attaching the second coupling lens to the frame.

Symbol description

1 scanning optical device

10Y first semiconductor laser

10M second semiconductor laser

20Y first coupling lens

20M second coupling lens

50 deflector

51 polygon mirror

H11 First laser holder

H2A first lens holder

F frame

H2 lens holder

Hf seat surface

Hf1 first seat surface

Hf21 second seat surface

P-photo-curable resin

X1 axis of rotation

Detailed Description

As shown in fig. 1 to 3, the scanning optical device 1 includes: frame F, incidence optical system Li, deflector 50, and scanning optical system Lo. The scanning optical device 1 is applied to an electrophotographic image forming apparatus. In the following description, a direction along the rotation axis X1 of the polygon mirror 51 shown in fig. 3 is referred to as a "first direction". The direction orthogonal to the first direction, that is, the direction in which the polygon mirror 51 and the first scanning lens 60 shown in fig. 3 are arranged is referred to as "second direction". In addition, a direction orthogonal to the first direction and the second direction is referred to as a "third direction". The third direction corresponds to the optical axis direction of the first semiconductor laser 10Y and the main scanning direction in the scanning optical system Lo, which will be described later. The first direction corresponds to the sub-scanning direction. The second direction corresponds to an orthogonal direction orthogonal to the rotation axis direction and the optical axis direction. The arrow in the drawings indicating each direction 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, a diaphragm plate 30, and a condensing lens 40 (see fig. 1).

The semiconductor laser 10 is a device that emits light. The semiconductor laser 10 is provided with four photosensitive drums 200 (see fig. 5) corresponding to the scanning exposure performed by the scanning optical device 1. Toner images of different colors are formed on the photosensitive drums 200.

In the present 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)". In the following description, the "first" may be given to the beginning of the name of the component corresponding to the first color, and the "Y" may be given to the end of the symbol of the component corresponding to the first color. In the same manner, the members corresponding to the second color, the third color, and the fourth color may be distinguished by labeling the first of the names "second", "third", and "fourth", and labeling the last of the symbols "M", "C", and "K".

The first semiconductor lasers 10Y are arranged at intervals in the first direction with respect to the second semiconductor lasers 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 lasers 10C are arranged at intervals in the second direction with respect to the second semiconductor lasers 10M. The third semiconductor laser 10C is located on the other side in the second direction with respect to the second semiconductor laser 10M. The fourth semiconductor laser 10K is arranged at intervals from the third semiconductor laser 10C in the first direction and from the first semiconductor laser 10Y in the second direction.

The coupling lens 20 is a lens that converts light from the semiconductor laser 10 into a light beam. The coupling lenses 20Y, 20M, 20C, and 20K corresponding to the respective colors are arranged at positions facing the corresponding semiconductor lasers 10Y, 10M, 10C, and 10K. The coupling lens 20 is a resin lens having an optical surface with both an incident surface and an exit surface being axisymmetric, and having a refractive index and a diffraction rate.

As shown in fig. 1, the aperture plate 30 is a part having an aperture stop 31 through which the light beam from the coupling lens 20 passes, and is integrally formed with the frame F. The aperture plate 30 is located between the coupling lens 20 and the condensing lens 40. The aperture plate 30 has a number of plural aperture stops 31Y, 31M, 31C, 31K corresponding to the plural semiconductor lasers 10Y, 10M, 10C, 10K.

The condenser lens 40 condenses the light flux from the coupling lens 20 on the polygon mirror 51 in the sub-scanning direction. The condenser lens 40 is located on the opposite side of the coupling lens 20 from the aperture plate 30. In other words, the condenser lens 40 is disposed between the aperture stop 31 and the polygon mirror 51.

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 light flux from the condenser lens 40 in the main scanning direction. The polygon mirror 51 has five mirror surfaces disposed equidistantly from the rotation axis X1. The motor 52 rotates the polygon mirror 51. The motor 52 is fixed to the frame F.

The scanning optical system Lo is an optical system that images the light beam deflected in the direction 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 corresponding to yellow, a second scanning optical system LoM corresponding to magenta, a third scanning optical system LoC corresponding to cyan, and a fourth scanning optical system LoK corresponding to black.

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 disposed on the other side of the polygon mirror 51 in the second direction. The light fluxes deflected in the main scanning direction by the polygon mirror 51 are incident on the respective scanning optical systems LoY, loM, loC, loK.

The first scanning optical system LoY includes: the first scanning lens 60YM, the second scanning lens 70Y, and the reflecting mirror 81Y.

The first scanning lens 60YM is a lens for refracting the light fluxes BY and BM deflected in the direction BY the deflector 50 in the main scanning direction to form an image on an image plane. The first scanning lens 60YM has an fθ characteristic such that the light scanned at an equiangular velocity by the deflector 50 becomes an equal 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 mirror 81Y is a mirror that reflects the light beam BY from the first scanning lens 60YM toward the image plane.

The second scanning lens 70Y is a lens for refracting the light beam BY reflected BY the mirror 81Y in the sub-scanning direction to form an image on the image plane. The second scanning lens 70Y is disposed at a position on one side in the first direction with respect to the polygon mirror 51. 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 includes: the first scanning lens 60YM, the second scanning lens 70M, the reflecting mirror 81M, and the mirror 82M.

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

The third scanning optical system LoC 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 includes a first scanning lens 60CK, a second scanning lens 70C, a reflecting mirror 81C, and a mirror 82C, and the first scanning lens 60CK, the second scanning lens 70C, the reflecting mirror 81C, and the mirror 82C have the same functions as the respective components of the second scanning optical system LoM.

The fourth scanning optical system LoK is 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 includes a first scanning lens 60CK, a second scanning lens 70K, and a reflecting mirror 81K, and the first scanning lens 60CK, the second scanning lens 70K, and the reflecting mirror 81K have the same functions as the respective components of the first scanning optical system LoY.

As shown in fig. 4, light emitted from the semiconductor lasers 10Y, 10M, 10C, and 10K passes through the corresponding coupling lenses 20Y, 20M, 20C, and 20K, and is converted into a light beam BY, BM, BC, BK. The light flux BY, BM, BC, BK passes through the aperture stops 31Y, 31M, 31C, and 31K of the aperture plate 30, and then enters the polygon mirror 51 through the condenser lens 40. The condenser lens 40 is a lens through which the light flux BY, BM, BC, BK passes in common, and is configured such that an incident surface is a cylindrical surface and an outgoing surface is a plane surface.

As shown in fig. 5, the polygon mirror 51 deflects the light beam BY, BM, BC, BK toward the corresponding scanning optical system LoY, loM, loC, loK. The light beam BY directed to the first scanning optical system LoY is reflected BY the reflecting mirror 81Y after passing through the first scanning lens 60YM, and is emitted to the image plane on one side in the first direction BY passing through the second scanning lens 70Y. The light beam BY is emitted from the second scanning lens 70Y at a predetermined angle to the first direction. The light beam BY is imaged on the surface of the first photosensitive drum 200Y and scanned in the main scanning direction.

The light beam BM directed to the second scanning optical system LoM is reflected by the mirror 82M and the reflecting mirror 81M after passing through the first scanning lens 60YM, and is emitted to the image plane on one side in the first direction by passing through the second scanning lens 70M. The light beam BM is emitted from the second scanning lens 70M at a predetermined angle to the first direction. The light beam BM images on the surface of the second photosensitive drum 200M and scans in the main scanning direction. The light fluxes BC and BK are similarly emitted to the image surface on one side in the first direction by the corresponding scanning optical systems LoC and LoK, are formed on the surfaces of the corresponding photosensitive drums 200C and 200K, and are scanned in the main scanning direction.

The frame F is made of resin and is integrally manufactured by molding. The frame F has a first concave portion CP1 shown in fig. 3 and a second concave portion CP2 shown in fig. 1. The first concave portion CP1 is open on one side in the first direction. The second concave portion CP2 is open on the other side in the first direction. As shown in fig. 5, a deflector 50 and a part of the scanning optical system Lo are disposed in the first concave portion CP 1. Specifically, the components of the scanning optical system Lo other than the respective mirrors 81 are disposed in the first concave portion CP 1. As shown in fig. 2, a coupling lens 20, an aperture plate 30, and a condenser lens 40 (see fig. 1) are disposed in the second concave portion CP2.

As shown in fig. 1, the frame F has a first base wall Fb1 located at the bottom of the first concave portion CP1 and a second base wall Fb2 located at the bottom of the second concave portion CP2.

The first base wall Fb1 and the second base wall Fb2 are walls intersecting in the first direction. In detail, the first base wall Fb1 and the second base wall Fb2 are walls in the first direction in the thickness direction. That is, the first base wall Fb1 and the second base wall Fb2 are walls having planes orthogonal in the first direction.

The second base wall Fb2 is located at a position offset to one side in the first direction with respect to the first base wall Fb1. As shown in fig. 5, the deflector 50 and the aforementioned part of the scanning optical system Lo are directly or indirectly attached to the first base wall Fb1 from one side in the first direction. Therefore, the deflector 50 and a part of the scanning optical system Lo are located 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 located on the other side in the first direction with respect to the second base wall Fb2. 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 mirror 81 is disposed near the first base wall Fb1 and exposed to the other side in the first direction with respect to the first base wall Fb 1. In other words, the first base wall Fb1 does not have a portion on the other side in the first direction of the mirror 81. Thereby, the reflecting mirror 81 is exposed to the other side in the first direction without being covered by the first base wall Fb1, and can be attached to the frame F from the other side in the first direction.

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 that constitute a substantially rectangular frame surrounding the respective concave portions CP1, CP 2.

The first side wall F41 is located on the opposite side of the semiconductor laser 10 from 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 opposite to the first side wall F41 with respect to the deflector 50. In detail, the second sidewall F42 is located at the opposite side of 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 opposite side of the deflector 50 from the first scanning lens 60 YM. The third side wall F43 is connected to one end portion of the first side wall F41, the first base wall Fb1, the second base wall Fb2, and the second side wall F42 in the second direction. A part of the third side wall F43 protrudes from the first base wall Fb1 to one side in the first direction, and the other part protrudes from the second base wall Fb2 to the other side in the first direction.

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

As shown in fig. 2, the scanning optical device 1 further includes a first laser holder H11 and a second laser holder H12 as an example of the first holding member; and a first lens holder H2A and a second lens holder H2B as an example of the second holding member. The first laser holder H11, the second laser holder H12, the first lens holder H2A, and the second lens holder H2B are made of resin. The first lens holder H2A and the second lens holder H2B are made of a material that is permeable to light for curing the photocurable resin.

The first laser holder H11 is a member for holding the first semiconductor laser 10Y, the second semiconductor laser 10M, and the first coupling lens 20Y in an L-shape in cross section. The first coupling lens 20Y is fixed to the first laser holder H11 by a photo-curable 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. The structure of the first laser holder H11 will be described in detail later. The second laser holder H12 is a member for holding the third semiconductor laser 10C, the fourth semiconductor laser 10K, and the fourth coupling lens 20K in an L-shape in cross section. The second laser holder H12 is different from the first laser holder H11 in only the object to be held, and is otherwise configured in the same manner as the first laser holder H11, and therefore a detailed description thereof is omitted.

The first lens holder H2A 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 H2A is fixed to the first laser holder H11 by a photo-curable resin. The first lens holder H2A can be attached to the first laser holder H11 from the other side in the first direction. The structure of the first lens holder H2A will be described in detail later. The second lens holder H2B is a member that holds the third coupling lens 20C at a position aligned in the first direction with respect to the fourth coupling lens 20K. The object and the fixed target held by the second lens holder H2B and the first lens holder H2A are changed to the second laser holder H12, and otherwise, the second lens holder H2B is configured in the same manner as the first lens holder H2A, and therefore, a detailed description thereof is omitted.

As shown in fig. 6 (a), the first laser holder H11 has: a first portion 111, a second portion 112, two third portions 113, a first bracket location 114, and a second bracket location 115.

The first portion 111 is a plate-like portion along the first direction in the thickness direction, and the dimension in the third direction is larger than the dimension in the second direction. The first portion 111 has a seating surface Hf. The seating surface Hf has a first seating surface Hf1 and a second seating surface Hf2. The first seating surface Hf1 and the second seating surface Hf2 are planes orthogonal in the first direction. The first seat surface Hf1 and the second seat surface Hf2 face the other side in the first direction. As shown in fig. 6 (c), the first portion 111 is disposed with a gap from the frame F in the first direction.

The first seating surface Hf1 is a seating surface to which the first coupling lens 20Y is fixed by the photo-curable resin. The first seating surface Hf1 is located at one end portion of the first portion 111 in the third direction.

The second seating surface Hf2 is a seating surface to which the first lens holder H2A is fixed by the photo-curable resin. The second seating surface Hf2 is provided one at each end portion of the first portion 111 in the second direction. The second seating surface Hf2 is located on the other side in the first direction than the first seating surface Hf 1.

As shown in fig. 6 (a), the second portion 112 extends from the end on the other side in the third direction of the first portion 111 toward the other side in the first direction. The second portion 112 has a first holding portion 112A holding the first semiconductor laser 10Y and a second holding portion 112B holding the second semiconductor laser 10M. The first holding portion 112A and the second holding portion 112B each have a hole penetrating in the third direction and a pair of semi-cylindrical ribs extending from the peripheral edge of the hole to the other side in the third direction. The semiconductor laser 10 is held by being pressed between a pair of ribs.

The third portion 113 extends from the first portion 111 toward one side in the first direction. The third portion 113 is provided one at each end of the first portion 111 in the second direction. The third portion 113 is formed over a predetermined range from the end on the other side in the third direction of the first portion 111. The first portion 111 protrudes to one side in the third direction than the third portion 113.

As shown in fig. 6 (b) and (c), the first holder positioning portion 114 is a portion for positioning the first laser holder H11 with respect to the frame F. The first bracket positioning portion 114 extends from the first portion 111 toward one side in the first direction. The first bracket positioning portion 114 is located between the two third portions 113 and connected to the two third portions 113. The first holder positioning portion 114 has a face 114A for positioning the first laser holder H11 in the third direction and a hole 114B for positioning the first holder positioning portion 114 in the first direction and the second direction.

As shown in fig. 6 (c), the frame F has a first boss F51 as an example of the first contact portion. The first boss F51 has a cylindrical shape protruding toward the other side in the third direction. The first boss F51 has a first positioning surface F511 which is a contact surface with the surface 114A of the first bracket positioning portion 114 in the third direction and a protrusion F512 fitted into the hole 114B. The first positioning surface F511 is a surface for positioning the first laser holder H11 in a third direction, which is an example of the first predetermined direction. The protrusion F512 is an example of a first restriction portion, and is a portion for positioning the first laser holder H11 in the first direction and the second direction, which are examples of the second predetermined direction. The protrusion F512 protrudes from the center of the first positioning surface F511.

A hole F513 (see fig. 7) into which the screw N is inserted is formed in the center of the tip surface of the protrusion F512. The first bracket positioning portion 114 is fixed to the frame F by a screw N in the third direction. In detail, the first bracket positioning portion 114 is sandwiched between the head of the screw N and the first positioning surface F511 of the first boss F51.

As shown in fig. 6 (b), the second holder positioning portion 115 is a portion that restricts the rotation of the first laser holder H11 about the first boss F51. The second bracket positioning portion 115 extends from the end of the second portion 112 on the other side in the first direction to the other side in the third direction, and then extends to the other side in the first direction. The second holder positioning portion 115 has a groove 115A for restricting the rotation of the first laser holder H11. The groove 115A penetrates in the third direction and opens on the other side in the first direction.

The frame F has a contact rib F52 as an example of the second contact portion. The contact rib F52 has a shape protruding toward one side in the first direction and protruding toward the other side in the third direction (see fig. 7). In a state where the first laser holder H11 is mounted to the frame F, the contact rib F52 enters into the groove 115A of the second holder positioning portion 115. The contact rib F52 contacts the groove 115A in the second direction. A gap for releasing thermal expansion is formed between the second bracket positioning portion 115 and the first direction of the frame F.

The first bracket positioning portion 114, the first holding portion 112A, the second holding portion 112B, and the second bracket positioning portion 115 are arranged in order from one side in the first direction. The first holding portion 112A and the second holding portion 112B are located between the first bracket positioning portion 114 and the second bracket positioning portion 115 in the first direction. In addition, the aforementioned first portion 111 is located between the first holding portion 112A and the first bracket positioning portion 114 in the first direction.

Accordingly, the first mount positioning portion 114, the first semiconductor laser 10Y, the second semiconductor laser 10M, and the second mount positioning portion 115 are sequentially arranged in the arrangement direction of the semiconductor lasers 10Y, 10M in a state where the semiconductor lasers 10Y, 10M are mounted on the first laser mount H11. In addition, in a state where the semiconductor lasers 10Y, 10M are mounted on the first laser holder H11, the semiconductor lasers 10Y, 10M are located between the first holder positioning portion 114 and the second holder positioning portion 115 in the arrangement direction. In addition, in a state where the semiconductor lasers 10Y, 10M are mounted on the first laser holder H11, the first semiconductor laser 10Y is located between the second semiconductor laser 10M and the first holder positioning portion 114 in the arrangement direction. In addition, in a state where the semiconductor lasers 10Y, 10M are mounted on the first laser holder H11, the first portion 111 is located between the first semiconductor laser 10Y and the first holder positioning portion 114 in the arrangement direction.

As shown in fig. 7, the frame F has two positioning portions F50, and the positioning portions F50 have the aforementioned first bosses F51 and contact ribs F52. The positioning portion F50 on one side in the second direction positions the first laser holder H11, and the positioning portion F50 on the other side in the second direction positions the second laser holder H12. Each first boss F51 protrudes from the second base wall Fb2 of the frame F toward the other side in the third direction. The first bosses F51 are arranged at intervals in the second direction.

The second side wall F42 is located opposite to the deflector 50 with respect to each first boss F51 (see fig. 1). The second side wall F42 has an opening F421 for making each of the aperture stops 31Y, 31M, 31C, 31K and each of the first bosses F51 face outward.

The opening F421 penetrates in the third direction and opens on one side in the first direction. Each contact rib F52 is formed on the other side edge in the first direction among the edges of the opening F421. Each contact rib F52 protrudes from the edge of the opening F421 to one side in the first direction.

As a result, as shown in fig. 8 (a), the aperture stops 31Y, 31M, 31C, 31K and the positioning portion F50 can be visually confirmed from the third direction in a state where no other member is attached to the frame F. The aperture stops 31Y and 31M and the positioning portion F50 on one side in the second direction are arranged on a straight line along the first direction as viewed from the third direction. The aperture stops 31C and 31K and the positioning portion F50 on the other side in the second direction are arranged on a straight line along the first direction as viewed from the third direction.

The aperture stops 31Y, 31M are located between the first boss F51 and the contact rib F52 on one side in the second direction in the first direction. The aperture stops 31C, 31K are located between the first boss F51 and the contact rib F52 on the other side in the second direction in the first direction.

As shown exaggeratedly in fig. 8 (b), the aperture 32 forming the aperture stop 31 has an opening on the side closer to the condenser lens 40 smaller than the opening on the side farther from the condenser lens 40. The aperture stop 31 is an opening of the hole 32 on the side close to the condenser lens 40.

As shown in fig. 9 (a), the first lens holder H2A has a lens mounting portion 21 and a leg portion 22. The lens mounting portion 21 is a portion to which the second coupling lens 20M is mounted. The lens mounting portion 21 is cylindrical, and a second coupling lens 20M is fitted to one end in the third direction. The lens mounting portion 21 protrudes to one side in the third direction with respect to the leg portion 22.

The foot 22 has a first foot 22A and a second foot 22B. The first leg 22A and the second leg 22B extend from the lens mounting portion 21 to one side in the first direction. Thus, as shown in fig. 9 (b), in a state where the first lens holder H2A is attached to the first laser holder H11, the leg portion 22 extends from the lens attachment portion 21 toward the second seating surface Hf2. The first leg 22A and the second leg 22B are separated in the second direction. The first leg 22A and the second leg 22B are fixed to the second seating surface Hf2 by photo-setting resins, respectively.

The first leg 22A and the second leg 22B of the first lens holder H2A are arranged so as to cross the optical path of the light from the first semiconductor laser 10Y. Thus, light traveling from the first semiconductor laser 10Y toward the first coupling lens 20Y passes between the first leg 22A and the second leg 22B.

Next, a method of manufacturing the scanning optical device 1 will be described. First, a method of attaching the coupling lens 20 to the frame F will be described, and finally, a method of molding the frame F will be described.

As shown in fig. 7, when the coupling lens 20 is mounted on the frame F, first, the laser holders H11 and H12 holding the state of the semiconductor laser 10 are mounted on the frame F by the screws N. After that, after the first bonding step shown in fig. 10 (a) and (b), the second bonding step shown in fig. 10 (c) and (d) is performed.

As shown in fig. 10 (a), in the first bonding step, first, the first coupling lens 20Y is held by using a jig J that clamps the first coupling lens 20Y from the second direction. Next, the uncured photo-curing resin P is disposed between the first coupling lens 20Y and the first seating surface Hf1 of the first laser holder H11. In the drawing, the first coupling lens 20Y is brought close to the first seating surface Hf1 after the photo-setting resin P is applied to the first seating surface Hf1 of the first laser holder H11.

Then, the jig J is moved to one side in the first direction, so that the first coupling lens 20Y approaches the first seating surface Hf1 from the other side in the first direction, and the photocurable resin P is sandwiched between the first coupling lens 20Y and the first seating surface Hf1. Then, the position of the first coupling lens 20Y with respect to the first semiconductor laser 10Y is adjusted by moving the jig J in the first direction, the second direction, and the third direction.

After the position is adjusted, light is irradiated to the photo-setting resin P, and as shown in fig. 10 (b), the first coupling lens 20Y is adhesively fixed to the first seating surface Hf1 of the first laser holder H11. The fourth coupling lens 20K is also adhesively fixed to the second laser holder H12 by the same method as the method of mounting the first coupling lens 20Y. In the present embodiment, the photo-curable resin P is an ultraviolet curable resin, and light for curing the resin P is ultraviolet.

As shown in fig. 10 (c), in the second bonding step, first, the first lens holder H2A holding the second coupling lens 20M is gripped by the jig J from the second direction. Next, the uncured photo-curing resin P is disposed between the first lens holder H2A and the second seating surface Hf2 of the first laser holder H11. In the drawing, the first lens holder H2A is brought close to the second seating surface Hf2 after the photo-setting resin P is applied to the second seating surface Hf2 of the first laser holder H11.

Then, the jig J is moved to one side in the first direction, so that the first lens holder H2A approaches the second seating surface Hf2 from the other side in the first direction, and the photocurable resin P is sandwiched between the first lens holder H2A and the second seating surface Hf2. Then, the position of the second coupling lens 20M with respect to the second semiconductor laser 10M is adjusted by moving the jig J in the first direction, the second direction, and the third direction.

After the position adjustment, the light is irradiated to the photo-setting resin P, whereby the first lens holder H2A is adhesively fixed to the second seating surface Hf2 of the first laser holder H11 as shown in fig. 10 (d). At this time, the light for curing the photo-curable resin P can be made to strike the photo-curable resin P through the transparent first lens holder H2A, and thus the entire photo-curable resin P can be reliably cured. The third coupling lens 20C is also fixed to the second laser holder H12 via the second lens holder H2B by the same method as the mounting method of the second coupling lens 20M.

As shown in fig. 12, in the method of molding the frame F, the frame F is injection molded using the injection molding die M having the first die M1, the second die M2, and the insert M3, whereby the aperture stop 31 and the positioning portion F50 are integrally formed in the frame F. The first mold M1 is a mold that forms one surface of the frame F in the first direction. The second mold M2 is a mold that forms the other surface of the frame F in the first direction. At least one of the first mold M1 and the second mold M2 is movable in the first direction.

The insert M3 is a mold for forming the positioning portion F50 of the frame F and the aperture stop 31. The insert M3 is movable in a third direction.

As shown in fig. 11, the insert M3 integrally has a first molding surface M31 and two second molding surfaces M32 and M33. The first shaping surface M31 is a surface for forming four aperture stops 31. The first molding surface M31 has four protrusions M311 for forming four aperture stops 31, in detail, four holes 32 (refer to fig. 8). The projection M311 is configured such that the area of the tip end portion when projected in the third direction is smaller than the cross-sectional area of the portion near the first molding surface M31. Thus, the opening of the hole 32 on the side close to the condenser lens 40 can be made small, and the insert M3 can be easily moved in the third direction to be separated from the frame F.

The second molding surface M32 is a surface for forming two first bosses F51. The second molding surface M32 has two concave portions M321 for forming two first bosses F51. The second molding surface M33 is a surface for forming two contact ribs F52 (see fig. 8). The second molding surface M33 has two concave portions M331 for forming two contact ribs F52.

The method for forming the frame F includes a first step, a second step, and a third step.

As shown in fig. 12, in the first step, the frame F is formed by injecting resin into the mold M in which the first mold M1, the second mold M2, and the insert M3 are combined.

In the second step, after the frame F is formed, at least one of the first mold M1 and the second mold M2 is moved in the first direction and separated from the frame F. In the third step, after the frame F is formed, the insert M3 is moved in the third direction and separated from the frame F. Through the above-described steps, the aperture stop 31 and the positioning portion F50 can be integrally formed with the frame F.

As described above, the following effects can be obtained in the present embodiment.

After the first coupling lens 20Y is mounted on the first seating surface Hf1 from the other side in the first direction, the first lens holder H2A holding the second coupling lens 20M can be mounted on the second seating surface Hf2 from the other side in the first direction, so that a plurality of coupling lenses 20 can be mounted from the same direction, and the complexity of the manufacturing process can be suppressed.

The first lens holder H2A has the leg portion 22 extending from the lens mounting portion 21, and therefore, the lens mounting portion 21 can be prevented from interfering with the first coupling lens 20Y.

The two legs 22A, 22B of the first lens holder H2A are fixed to the first laser holder H11, and therefore the second coupling lens 20M can be stably held by the first lens holder H2A.

When the first lens holder H2A is fixed to the first laser holder H11, light can be passed through the transparent first lens holder H2A to cure the photo-curable resin P, and thus the fixation of the first lens holder H2A to the first laser holder H11 can be easily performed.

The second portion 112 holding the first semiconductor laser 10Y is integrated with the seating surface Hf on which the first coupling lens 20Y is fixed, so that the positional accuracy of the first coupling lens 20Y with respect to the first semiconductor laser 10Y can be improved.

Since the first laser holder H11 and the first lens holder H2A are both made of resin, the linear expansion coefficients of the first laser holder H11 and the first lens holder H2A can be unified, and therefore, misalignment of the first coupling lens 20Y and the second coupling lens 20M can be suppressed when the first laser holder H11 and the first lens holder H2A thermally expand. Further, the first laser holder H11 and the first lens holder H2A can be configured to compensate for changes in refractive index and diffraction rate of the first coupling lens 20Y and the second coupling lens 20M due to temperature fluctuations by using their linear expansion coefficients.

Since the mount positioning portions 114 and 115 and the semiconductor lasers 10Y and 10M are aligned in the alignment direction, tolerance management can be easily performed.

Since the first semiconductor laser 10Y and the second semiconductor laser 10M are arranged in the sub-scanning direction, the first semiconductor laser 10Y and the second semiconductor laser 10M having different image surfaces exposed to light can be mounted on one first laser holder H11.

The frame F has the first boss F51 contacting the first holder positioning portion 114 in the third direction, and thus the first laser holder H11 can be positioned in the third direction with respect to the frame F.

The frame F has the contact rib F52 that contacts the second holder positioning portion 115 in the second direction, and thus the first laser holder H11 can be restrained from rotating relative to the frame F.

Since the first coupling lens 20Y is fixed to the seating surface Hf by the photo-setting resin, the first coupling lens 20Y can be fixed to the seating surface Hf by adjusting the first coupling lens 20Y with respect to the first semiconductor laser 10Y and then directing light to the photo-setting resin.

The first portion 111 is disposed with a gap from the frame F in the first direction, and therefore the seating surface Hf is not affected by the tolerance of the frame F and the first laser holder H11 to each other.

Since the first laser holder H11 is made of resin, the degree of freedom in the shape of the first laser holder H11 can be increased, and the setting range of the linear expansion coefficient can be increased.

Since the aperture stop 31 and the positioning portion F50 are formed of the same insert M3, the positional accuracy of the aperture stop 31 and the positioning portion F50 can be improved.

The aperture 32 forming the aperture stop 31 is formed such that the aperture on the side closer to the condenser lens 40 is smaller than the aperture on the side farther from the condenser lens 40, whereby the size of the aperture stop 31 as the aperture closer to the condenser lens 40 can be set as a reference size.

The rigidity of the frame F can be improved by providing the second side wall F42, and the aperture stop 31 and the positioning portion F50 can be formed by the same insert M3 by forming the aperture F421 in the second side wall F42.

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

In the above embodiment, the first holding member is used as the laser holder, but the present invention is not limited to this, and the first holding member may be, for example, a frame of the scanning optical device. In this case, the semiconductor laser may be held by a laser holder attached to the frame or may be held by the frame.

In the above embodiment, the second holding member is fixed to the seating surface of the first holding member by the photo-setting resin, but the present invention is not limited to this, and for example, the second holding member may be fixed to a portion other than the seating surface of the first holding member by the photo-setting resin. The number of the legs of the second holding member may be one or three or more.

In the above embodiment, the coupling lens and the like are fixed to the seating surface using the photo-setting resin, but the present invention is not limited to this, and for example, an adhesive other than the photo-setting resin may be used to fix the coupling lens and the like to the seating surface.

In the above embodiment, the first lens holder and the second lens holder are made of transparent resin, but the present invention is not limited to this, and a material that allows light to pass through for curing a light-curable resin other than transparent resin may be used. In addition, a structure may be provided in which light can reach between the first lens holder and the second mount surface and between the second lens holder and the second mount surface.

In the above embodiment, the positioning portion is formed in a convex shape, but the present invention is not limited to this, and the positioning portion may be formed in a concave shape in the optical axis direction.

In the above embodiment, the first contact portion is formed as the boss and the hole into which the boss enters is formed in the first bracket positioning portion, but the present invention is not limited to this, and the first bracket positioning portion may be formed as the boss and the hole into which the boss enters is formed in the first contact portion.

The semiconductor laser 10 may have a structure having a plurality of light emitting points. Thus, a plurality of light beams from the semiconductor laser 10 may be converted into a plurality of light beams by one coupling lens 20, and imaged on the surface of the photosensitive drum 200 by the scanning optical system Lo corresponding to the plurality of light beams. In the case of such a configuration, each of the light fluxes BY, BM, BC, BK of the above-described embodiment includes a plurality of light fluxes.

Next, a modified example of the above embodiment will be described mainly with reference to fig. 13 to 17, focusing on points different from the above embodiment. In the above embodiment, the embodiment in which the second holding member is constituted by the first lens holder H2A holding the second coupling lens 20M and the second lens holder H2B holding the third coupling lens 20C is exemplified. In the modification shown below, the second holding member is constituted by a separate lens holder H2.

As shown in fig. 13, the scanning optical device 1 further includes a first laser holder H11 and a second laser holder H12 as an example of the first holding member; and a lens holder H2 as an example of the second holding member. The first laser holder H11, the second laser holder H12, and the lens holder H2 are made of resin.

The lens holder H2 is a member that holds the second coupling lens 20M and the third coupling lens 20C. Specifically, the lens holder H2 holds the second coupling lenses 20M at positions aligned in the first direction with respect to the first coupling lenses 20Y. In addition, the lens holder H2 holds the third coupling lens 20C at a position aligned in the first direction with respect to the fourth coupling lens 20K.

The lens holder H2 is fixed to the second base wall Fb2 of the frame F by a screw N1. The lens holder H2 can be attached to the second base wall Fb2 from the other side in the first direction. The structure of the lens holder H2 will be described in detail later.

As shown in fig. 14, the lens holder H2 has a base H21 and a foot H22. The base H21 has two second seating surfaces Hf21, hf22. The two second seating surfaces Hf21, hf22 are arranged at intervals in the second direction. The second seating surface Hf21 on one side in the second direction is a seating surface to which the second coupling lens 20M is fixed by the photo-setting resin. The second seating surface Hf22 on the other side in the second direction is a seating surface to which the third coupling lens 20C is fixed by the photo-setting resin. The two second seating surfaces Hf21, hf22 are planes orthogonal in the first direction. The base portion H21 protrudes toward one side in the third direction with respect to the leg portion H22. The base portion H21 covers the first coupling lens 20Y and the fourth coupling lens 20K from the other side in the first direction (see fig. 13).

The leg portion H22 has a first leg portion H22A and a second leg portion H22B. The first leg H22A and the second leg H22B are separated in the second direction. The first leg H22A and the second leg H22B extend from the base H21 to one side in the first direction. In other words, the first leg H22A and the second leg H22B extend from the base H21 toward the opposite side of the second seating surfaces Hf21, hf22. The first leg H22A and the second leg H22B extend in directions away from each other after extending from the base H21 to one side in the first direction.

The two second seating surfaces Hf21, hf22 are located between the first leg H22A and the second leg H22B in the second direction. As shown in fig. 13, the first leg H22A and the second leg H22B are fixed to the second base wall Fb2 of the frame F by screws N1, respectively.

The first leg H22A and the second leg H22B of the lens holder H2 are arranged so as to cross the optical paths of the light from the first semiconductor laser 10Y and the fourth semiconductor laser 10K. Thus, the light traveling from the first semiconductor laser 10Y to the first coupling lens 20Y and the light traveling from the fourth semiconductor laser 10K to the fourth coupling lens 20K pass between the first leg H22A and the second leg H22B.

The first leg H22A and the second leg H22B have a face H23 for positioning the lens holder H2 in the first direction and a hole H24 for positioning the lens holder H2 in the third direction, respectively.

As shown in fig. 15 and 16, the second base wall Fb2 of the frame F has two second positioning surfaces F61 for positioning the lens holder H2 in the first direction and two cylindrical second bosses F62 for positioning the lens holder H2 in the third direction. The second positioning surface F61 faces the other side in the first direction. In a state where the lens holder H2 is attached to the frame F, the second positioning surface F61 is in contact with the surface H23 of the lens holder H2.

The second boss F62 is an example of a second regulating portion, and protrudes from the second positioning surface F61 to the other side in the first direction. The second boss F62 is fitted into the hole H24 of the lens holder H2 in a state where the lens holder H2 is mounted to the frame F.

A hole F621 into which the screw N1 is inserted is formed in the center of the tip end surface of the second boss F62. In a state where the lens holder H2 is attached to the frame F, the tip end portion of the leg portion H22 is sandwiched between the head portion of the screw N1 and the second positioning surface F61 (see fig. 17 (a) and (b)).

As shown in fig. 15, the second boss F62 and the second positioning surface F61 intersect the first plane PF1 including the aforementioned first positioning surface F511. Specifically, the first plane PF1 is a plane obtained by extending the first positioning surface F511, and is parallel to the first positioning surface F511 and passes through the first positioning surface F511. In the present embodiment, the second positioning surface F61 is orthogonal to the first plane PF 1. In addition, the first plane PF1 passes through the center of the second boss F62.

As shown in fig. 16, the protrusion F512 and the first positioning surface F511 of the first boss F51 intersect the second plane PF2 including the second positioning surface F61. Specifically, the second plane PF2 is a plane obtained by extending the second positioning surface F61, and is parallel to the second positioning surface F61 and passes through the second positioning surface F61. In this embodiment, the first positioning plane F511 is orthogonal to the second plane PF 2. In addition, the second plane PF2 passes through the center of the first boss F51.

Next, a method of manufacturing the scanning optical device 1 will be described. In detail, a method of attaching the coupling lens 20 to the frame F will be described.

In the case of attaching the coupling lens 20 to the frame F, first, as in the above-described embodiment, as shown in fig. 7, after the laser holders H11 and H12 holding the semiconductor laser 10 are attached to the frame F by the screws N, the first bonding step shown in fig. 10 (a) and (b) is performed. Thereafter, the mounting steps shown in fig. 17 (a) and (b) are performed, and the second bonding step shown in fig. 17 (b) and (c) is further performed.

As shown in fig. 17 (a) and (b), in the mounting step, the lens holder H2 is mounted to the frame F by the screw N1. The lens holder H2 and the screw N1 may be attached by the hand of an operator or by a dedicated machine.

As shown in fig. 17 (b), in the second bonding step, first, the second coupling lens 20M is gripped by the jig J from the second direction. Next, the uncured state photo-curing resin P is disposed between the second coupling lens 20M and the second seating surface Hf21 of the lens holder H2. In the drawing, the second coupling lens 20M is brought close to the second seating surface Hf21 after the photo-setting resin P is applied to the second seating surface Hf21 of the lens holder H2.

Then, the jig J is moved to one side in the first direction, so that the second coupling lens 20M approaches the second seating surface Hf21 from the other side in the first direction, and the photo-curable resin P is sandwiched between the second coupling lens 20M and the second seating surface Hf21. Then, the position of the second coupling lens 20M with respect to the second semiconductor laser 10M is adjusted by moving the jig J in the first direction, the second direction, and the third direction.

After the position is adjusted, light is irradiated to the photo-setting resin P, and as shown in fig. 17 (c), the second coupling lens 20M is adhesively fixed to the second seating surface Hf21 of the lens holder H2. The third coupling lens 20C is also adhesively fixed to the second seating surface Hf22 of the lens holder H2 by the same method as the mounting method of the second coupling lens 20M.

As described above, the following effects can be obtained in the present modification.

The plurality of coupling lenses 20 can be mounted from the same direction, and thus, the complexity of the manufacturing process can be suppressed.

The lens holder H2 has a leg portion H22 extending from the base portion H21, and therefore interference between the base portion H21 and the first coupling lens 20Y can be suppressed.

The two leg portions H22A, H B of the lens holder H2 are fixed to the frame F, and therefore the second coupling lens 20M can be stably held by the lens holder H2.

Since the portion holding the first semiconductor laser 10Y is integrated with the first seating surface Hf1 to which the first coupling lens 20Y is fixed, the positional accuracy of the first coupling lens 20Y with respect to the first semiconductor laser 10Y can be improved.

Since the second boss F62 intersects the first plane PF1, the second boss F62 and the first positioning surface F511 are disposed at substantially the same position in the third direction, and therefore, the influence of thermal expansion of the brackets H11, H12, H2 in the third direction can be reduced.

The frame may have a first restricting portion for positioning the first holding member in a second predetermined direction and a second positioning surface for positioning the second holding member in the second predetermined direction, and the first restricting portion may intersect a second plane including the second positioning surface.

Since the protrusion F512 of the first boss F51 intersects the second plane PF2, the protrusion F512 and the second positioning surface F61 are disposed at substantially the same position in the first direction, and therefore, the influence of thermal expansion of the brackets H11, H12, H2 in the first direction can be reduced.

Since the second coupling lens 20M and the third coupling lens 20C are fixed to the second seating surfaces Hf21 and Hf22 of the lens holder H2, the number of components can be reduced as compared with a structure in which the third coupling lens is fixed to a component different from the component holding the second coupling lens, for example.

The first laser holder H11, the second laser holder H12, and the lens holder H2 are each made of resin, and thus the linear expansion coefficients of the first laser holder H11, the second laser holder H12, and the lens holder H2 can be unified, and misalignment of the four coupling lenses 20 can be suppressed when the first laser holder H11, the second laser holder H12, and the lens holder H2 are thermally expanded. In addition, the changes in refractive index and diffraction rate of the four coupling lenses 20 due to the temperature fluctuation can be compensated for by the linear expansion coefficients of the first laser holder H11, the second laser holder H12, and the lens holder H2.

The present modification can be utilized in various ways as exemplified below.

The method of fixing the frame to the second holding member is not limited to the screw, and may be fixed by, for example, an adhesive, fitting, or the like.

The first seat surface and the second seat surface may be oriented such that the first seat surface and the second seat surface are orthogonal in, for example, the second direction.

The first restriction portion is a protrusion F512 and the second restriction portion is a second boss F62, and each restriction portion may be a recess or a hole. The first predetermined direction and the second predetermined direction may be different from the above-described direction.

The number of feet of the second holding member may be one or more than three.

The elements described in the above embodiments and modifications may be arbitrarily combined and implemented.

Claims (11)

1. A scanning optical device is characterized by comprising:

a first semiconductor laser that emits light;

a second semiconductor laser that emits light;

a first coupling lens that converts light from the first semiconductor laser into a light beam;

a second coupling lens that converts light from the second semiconductor laser into a light beam;

a polygon mirror that deflects the light beam from the first coupling lens and the light beam from the second coupling lens;

a first holding member that holds the first coupling lens and has a seating surface to which the first coupling lens is fixed by a photo-setting resin; and

a second holding member that holds the second coupling lens,

the second holding member holds the second coupling lenses at positions aligned in the rotation axis direction with respect to the first coupling lenses, and is fixed to the first holding member by a photo-setting resin.

2. The scanning optical device according to claim 1, wherein,

the seating surface is a plane orthogonal to the rotation axis direction.

3. The scanning optical device according to claim 1, wherein,

the second holding member has:

a lens mounting portion to which the second coupling lens is mounted; and

a leg portion extending from the lens mounting portion toward the seat surface,

the leg portion is fixed to the seat surface by a photo-setting resin.

4. A scanning optical device as claimed in claim 3, characterized in that,

the foot has:

a first foot; and

a second leg portion which is separated from the first leg portion in an orthogonal direction orthogonal to the rotation axis direction and the optical axis direction of the first semiconductor laser,

light traveling from the first semiconductor laser to the first coupling lens passes between the first leg and the second leg.

5. The scanning optical device according to claim 1, wherein,

the second holding member is made of a material that is transparent to light for curing the photocurable resin.

6. The scanning optical device according to claim 1, wherein,

The second semiconductor lasers are arranged in the rotation axis direction of the polygon mirror with respect to the first semiconductor lasers,

the first holding member has:

a first portion having the seating surface; and

and a second portion extending from the first portion in the rotation axis direction and holding the first semiconductor laser and the second semiconductor laser.

7. The scanning optical device according to claim 1, wherein,

the first holding member and the second holding member are made of resin.

8. A method for manufacturing a scanning optical device, the scanning optical device comprising:

a first semiconductor laser that emits light;

a second semiconductor laser that emits light;

a first coupling lens that converts light from the first semiconductor laser into a light beam;

a second coupling lens that converts light from the second semiconductor laser into a light beam;

a polygon mirror that deflects the light beam from the first coupling lens and the light beam from the second coupling lens;

A first holding member that holds the first coupling lens and has a seating surface to which the first coupling lens is fixed; and

a second holding member that holds the second coupling lens,

the second holding member holds the second coupling lens at a position aligned in the rotation axis direction with respect to the first coupling lens,

the method for manufacturing the scanning optical device is characterized by comprising the following steps:

a first bonding step of adjusting a position of the first coupling lens with respect to the first semiconductor laser and bonding and fixing the first coupling lens to the seating surface of the first holding member; and

and a second bonding step of adjusting a position of the second coupling lens with respect to the second semiconductor laser and bonding and fixing the second holding member to which the second coupling lens is attached to the first holding member.

9. The method of manufacturing a scanning optical device according to claim 8, wherein,

in the first bonding step of the present invention,

a photo-curable resin is disposed between the first coupling lens and the seating surface,

after the position of the first coupling lens is adjusted, the first coupling lens is adhesively fixed to the seating surface by irradiating light to the photocurable resin,

In the second bonding step of the present invention,

a photocurable resin is disposed between the second holding member and the first holding member,

after the position adjustment of the second coupling lens is performed, the second holding member is adhesively fixed to the first holding member by irradiating light to the photocurable resin.

10. The method of manufacturing a scanning optical device according to claim 8, wherein,

the position adjustment of the first coupling lens is performed using a jig that clamps the first coupling lens in an orthogonal direction orthogonal to an optical axis direction of the first semiconductor laser and the rotation axis direction.

11. The method of manufacturing a scanning optical device according to claim 10, wherein,

the jig clamps the second holding member from the orthogonal direction to adjust the position of the second coupling lens.

Images