Scanning optical device

Abstract

To facilitate the insertion of a lead terminal of a semiconductor laser into a hole of a substrate.SOLUTION: A scanning optical device 5 includes a first semiconductor laser LDM having a first lead terminal TM, a polygonal mirror 54 that deflects and scans light from the first semiconductor laser LDM, and a laser substrate 100 having a hole 101M into which a first lead terminal TM of the first semiconductor laser LDM is inserted and configured to control the first semiconductor laser LDM. A scanner frame 50 includes a first positioning unit 151 that positions the laser substrate 100 in a long side direction, and a second positioning unit 152 and a third positioning unit 153 that position the laser substrate 100 in a short side direction. The second positioning unit 152 and the third positioning unit 153 are disposed on one side and the other side respectively with the first semiconductor laser LDM therebetween in the long side direction.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a scanning optical device including a deflector that deflects light from a semiconductor laser.

Background Art

[0002] Conventionally, as described in Patent Document 1, for example, there is known a device having a positioning portion for positioning a substrate connected to a laser light source on a side wall of a housing of an image forming apparatus.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the image forming apparatus described in Patent Document 1, the side wall of the housing has two circular bosses for positioning, and the bosses are positioned by engaging with the terminal insertion holes of the substrate. The bosses are configured such that the tip portions have a small diameter and can guide the terminal insertion holes of the substrate. However, since the substrate has a degree of freedom of movement in the radial direction of the bosses, when inserting the lead terminals of the laser light source into the terminal insertion holes of the substrate, it may require man-hours.

[0005] An object of the present invention is to provide a scanning optical device capable of easily inserting the lead terminals of a semiconductor laser into the holes of a substrate.

Means for Solving the Problems

[0006] To achieve the above object, an image forming apparatus of the present invention includes a first semiconductor laser having lead terminals, a deflector that deflects and scans light from the first semiconductor laser, A laser substrate having a hole into which the lead terminal of the first semiconductor laser is inserted, and which controls the first semiconductor laser, and a scanner frame that supports the first semiconductor laser, the deflector, and the laser substrate. The scanner frame has a first positioning portion that protrudes in a direction penetrating the laser substrate and positions the laser substrate in the longitudinal direction, a second positioning portion that protrudes in a direction penetrating the laser substrate and positions the laser substrate in the short-side direction, and a third positioning portion that protrudes in a direction penetrating the laser substrate and positions the laser substrate in the short-side direction. The second positioning portion and the third positioning portion are respectively disposed on one side and the other side of the first semiconductor laser across the first semiconductor laser in the longitudinal direction of the laser substrate.

[0007] In the scanning optical device of the present invention, in the scanner frame, a first positioning portion for positioning the laser substrate in the longitudinal direction, and a second positioning portion and a third positioning portion for positioning the laser substrate in the short-side direction are provided. When attaching the laser substrate to the scanner frame, first, the longitudinal position of the laser substrate is positioned using the first positioning portion. Thereafter, with the longitudinal direction positioned, the short-side position of the laser substrate is positioned in order, either the second positioning portion or the third positioning portion, and then the other. With such a procedure, the laser substrate can be attached to the scanner frame while restricting the position of the laser substrate by the first to third positioning portions, making it easy to insert the lead terminal of the first semiconductor laser into the hole of the laser substrate.

[0008] Furthermore, the scanning optical device has a second semiconductor laser disposed side by side with the first semiconductor laser in the longitudinal direction of the laser substrate, and the position of the first positioning portion in the longitudinal direction of the laser substrate may be between the position of the first semiconductor laser in the longitudinal direction and the position of the second semiconductor laser in the longitudinal direction.

[0009] In the scanning optical device of the present invention, the distance from the first positioning unit to the first semiconductor laser and the distance from the first positioning unit to the second semiconductor laser can be made substantially the same. As a result, while positioning the laser substrate in the longitudinal direction by the first positioning unit, the lead terminals of the first semiconductor laser and the second semiconductor laser can be inserted into the holes of the laser substrate almost simultaneously. Further, even when there is a difference in the coefficient of thermal expansion between the laser substrate and the scanner frame, since the distances from the first positioning unit to the first semiconductor laser or the second semiconductor laser are substantially the same as described above, the adverse effects due to the above thermal expansion difference can be reduced.

[0010] Furthermore, the scanning optical device has a third semiconductor laser arranged side by side with the first semiconductor laser in the short side direction of the laser substrate, and the positions of the second positioning unit and the third positioning unit in the short side direction may be between the position of the first semiconductor laser in the short side direction and the position of the third semiconductor laser in the short side direction.

[0011] In the scanning optical device of the present invention, the distance from the second positioning unit and the third positioning unit to the first semiconductor laser and the distance from the second positioning unit and the third positioning unit to the third semiconductor laser can be made substantially the same. As a result, while positioning the laser substrate in the short side direction by the second positioning unit and the third positioning unit, the lead terminals of the first semiconductor laser and the third semiconductor laser can be inserted into the holes of the laser substrate almost simultaneously. Further, even when there is a difference in the coefficient of thermal expansion between the laser substrate and the scanner frame, since the distances from the second and third positioning units to the first semiconductor laser and the distances from the second and third positioning units to the third semiconductor laser are substantially the same as described above, the adverse effects due to the above thermal expansion difference can be reduced.

[0012] Furthermore, the scanning optical device may include a first screw and a second screw for fastening the laser substrate to the scanner frame, and the first screw and the second screw may be arranged on a straight line connecting the second positioning portion and the third positioning portion, and the first screw and the second screw may be respectively arranged on one side and the other side of the first semiconductor laser in the longitudinal direction of the laser substrate.

[0013] When there is a difference in the coefficient of thermal expansion between the laser substrate and the scanner frame, the influence becomes more prominent at a portion farther from the second positioning portion and the third positioning portion, and stress is generated. In the present invention, since the first screws for fastening are located between the second positioning portion and the third positioning portion which are separated from each other in the longitudinal direction, at least in the short direction, the above influence can be reduced, and the adverse effects caused by the generation of stress can be suppressed.

[0014] Furthermore, the scanning optical device may include an elastic member interposed between the head of the first screw and the laser substrate. In the present invention, instead of directly pressing and fastening the laser substrate with the first screw, an elastic member is interposed. Thereby, even when there is a difference in the coefficient of thermal expansion between the laser substrate and the scanner frame, the displacement between the laser substrate and the scanner frame due to the difference in thermal expansion can be released by the sliding on the surface of the elastic member, and the generation of stress can be suppressed.

[0015] In addition, the laser substrate may include a first to-be-positioned portion positioned by the first positioning portion passing therethrough, and the first to-be-positioned portion may be a groove extending in the short direction. Since the first to-be-positioned portion is a groove in the short direction, when the laser substrate is attached to the scanner frame, freedom in the short direction can be provided. Thereby, when attaching the laser substrate, it is easy to surely insert the lead terminals of the first semiconductor laser into the holes of the laser substrate.

[0016] In addition, the first positioning portion may include a positioning surface extending in the short direction along the groove. In the present invention, since the first positioning portion has a positioning surface extending in the short side direction, rotation of the laser substrate (rotation about an axis orthogonal to the surface of the laser substrate) can be restricted when the laser substrate is inserted into the groove. As a result, attachment of the laser substrate to the scanner frame becomes even easier.

[0017] Further, one end of the groove in the short side direction may be open. In the present invention, one end in the short side direction of the first positioned portion having a groove shape is released. Thereby, the first positioning portion can be easily engaged with the first positioned portion.

[0018] Further, the second positioning portion may have a substantially cylindrical shape. Since the second positioning portion has a substantially cylindrical shape, handling and engagement when attaching the laser substrate to the scanner frame are easy.

[0019] Further, the second positioning portion may integrally include a rib portion for strength reinforcement on the base portion side of the substantially cylindrical shape. The strength can be increased and the rigidity can be increased as compared with the case where the second positioning portion has only a simple cylindrical shape.

[0020] Further, the scanner frame may have a contact portion that protrudes in a direction penetrating the laser substrate and contacts an end portion of the laser substrate in the short side direction. By contacting and guiding the end portion of the laser substrate when attaching the laser substrate to the scanner frame, rotation of the laser substrate (rotation about an axis orthogonal to the surface of the substrate) can be restricted.

[0021] Further, the scanner frame may include a frame body that supports the deflector and the laser substrate, a laser holder into which the first semiconductor laser is press-fitted, and a third screw that fixes the laser holder to the frame body. In the present invention, the assembly process can be smoothly carried out in the following flow: press-fitting the first semiconductor laser into the laser holder, fixing the laser holder to the main body of the scanner frame with screws, and then attaching the laser substrate to the scanner frame (soldering by passing the lead terminals through the holes in the substrate).

Advantages of the Invention

[0022] According to the present invention, it is possible to facilitate inserting the lead terminals of the semiconductor laser into the holes in the substrate.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[0024] Next, an embodiment of the present invention will be described in detail with appropriate reference to the drawings.

[0025] <Overview of Color Printer> As shown in FIG. 1, a color printer 1, which is an example of an image forming apparatus according to the present embodiment, is a printer that can perform printing with a total of four-color developers including yellow, magenta, cyan, and black in this example. The color printer 1 includes a paper feeding unit 3 that supplies paper (not shown) and an image forming unit 4 that forms an image on the supplied paper within a main body frame 2. The image forming unit 4 includes a scanning optical device 5, four process units 6, a transfer device 7, and a fixing unit 8. The side where the paper feeding unit 3 is located is the front side of the main body frame 2, and the side where the fixing unit 8 is located is the rear side of the main body frame 2.

[0026] The four process units 6 include process units 6Y, 6M, 6C, and 6K, and these process units 6Y, 6M, 6C, and 6K are arranged side by side in this order from the front side to the rear side. The process units 6Y, 6M, 6C, and 6K contain yellow, magenta, cyan, and black developers, respectively. In this specification, hereinafter, when identifying each component corresponding to the color of the developer, as described above, symbols Y, M, C, and K are attached and expressed corresponding to yellow, magenta, cyan, and black, respectively. In addition, when collectively referring to these components without distinguishing the color of the developer, they are expressed without attaching the symbols Y, M, C, and K.

[0027] The process units 6Y, 6M, 6C, and 6K each include a cylindrical photoreceptor 61Y, 61M, 61C, and 61K. Each photoreceptor 61Y, 61M, 61C, and 61K is held by the main body frame 2 and is arranged at a predetermined interval in the front-rear direction. Each process unit 6 includes a charger 62, a developing roller 63, a supply roller 64, and a toner storage unit 66 that stores the developer.

[0028] The paper feeding unit 3 includes a paper feeding tray 31 that stores paper and a paper feeding mechanism 32 that supplies the paper from the paper feeding tray 31 to the image forming unit 4. The side where the paper feeding tray 31 is located is the lower side of the main body frame 2.

[0029] The scanning optical device 5 irradiates the groups of light beams BY, BM, BC, and BK based on the print data onto the surfaces of the photoreceptors 61Y, 61M, 61C, and 61K, respectively. By the irradiation, the surfaces of the photoreceptors 61Y, 61M, 61C, and 61K are exposed and an electrostatic latent image is formed.

[0030] The transfer device 7 includes a driving roller 71, a driven roller 72, a transfer belt 73 annularly spanned between the driving roller 71 and the driven roller 72, and four transfer rollers 74. The surface located on the outer side of the annulus of the transfer belt 73 is in contact with each photoreceptor 61. The transfer rollers 74 are arranged inside the annulus of the transfer belt 73. The four transfer rollers 74 include transfer rollers 74Y, 74M, 74C, and 74K that sandwich the transfer belt 73 between the transfer rollers 74Y, 74M, 74C, and 74K and the photoreceptors 61Y, 61M, 61C, and 61K, respectively.

[0031] The fixing unit 8 includes a heating roller 81 and a pressure roller 82 that presses the heating roller 81.

[0032] <Image forming operation on the paper> In the image forming unit 4, the surfaces of the photoreceptors 61Y, 61M, 61C, and 61K are uniformly charged by the charger 62. By irradiating and exposing the groups of light beams BY, BM, BC, and BK from the scanning optical device 5, electrostatic latent images based on the print data are respectively formed on the photoreceptors 61Y, 61M, 61C, and 61K. The developer of each color carried on the developing roller 63 is supplied to the electrostatic latent images respectively formed on the photoreceptors 61Y, 61M, 61C, and 61K, and the electrostatic latent images are visualized. Developer images are formed on the photoreceptors 61Y, 61M, 61C, and 61K.

[0033] The paper, which is an example of a transfer medium supplied from the paper feed unit 3, moves on the transfer belt 73 from the front side to the rear side while sequentially contacting the photoreceptors 61Y, 61M, 61C, and 61K. The developer images formed on the photoreceptors 61Y, 61M, 61C, and 61K are sequentially superimposed and transferred onto a common sheet of paper from the photoreceptors 61 by a transfer roller 74 to which a transfer bias is applied. The paper onto which the developer image has been transferred passes between the heating roller 81 and the pressure roller 82, whereby the developer image is thermally fixed, and is discharged above the main body frame 2 by the conveying roller 23.

[0034] <Schematic of the Scanning Exposure Device> As shown in FIGS. 2, 3, 4, and 1, the scanning optical device 5 includes a scanner frame 50. The scanner frame 50 is the frame of the scanning optical device 5. Inside the scanner frame 50, four light source devices 51M, 51K, 51Y, and 51C that respectively emit light beam groups BM, BK, BY, and BC are provided. The light source devices 51M, 51K, 51Y, and 51C each have a semiconductor laser LDM, LDK, LDY, LDC and a coupling lens CLM, CLK, CLY, CLC. The semiconductor lasers LDM, LDK, LDY, and LDC are composed of a first semiconductor laser LDM, a second semiconductor laser LDC, a third semiconductor laser LDY, and a fourth semiconductor laser LDK, and each has a plurality of emission points. Each light beam group B is composed of a plurality, in this example two beams, corresponding to the emission points.

[0035] The scanning optical device 5 also includes a single polygon mirror 54 and a scanning optical system. In the present embodiment, a motor (not shown) for rotating the polygon mirror 54 is provided on a polygon substrate (not shown) including the polygon mirror 54, and a deflector is formed by the polygon mirror 54, the polygon substrate, and the motor. The scanning optical system includes two cylindrical lenses, two first scanning lenses 55, a plurality of reflecting mirrors 56, and four second scanning lenses 57. That is, the scanner frame 50 is an optical box that houses the polygon mirror 54 and the scanning optical system, and the first to fourth semiconductor lasers LDM, LDC, LDY, LDK and the deflector including the polygon mirror 54 are supported by the scanner frame 50.

[0036] <Details of the light source device> The coupling lens CL constitutes the incident optical system and condenses the laser light emitted from the semiconductor laser LD and converts it into a light beam group B.

[0037] The cylindrical lens refracts the light beam group B from the coupling lens CL to condense it in the sub-scanning direction in order to correct the tilt of the polygon mirror 54, and forms an image in a linear shape that is long in the main scanning direction on the reflecting surface 54A of the polygon mirror 54. The main scanning direction is the direction deflected by the polygon mirror 54, and the sub-scanning direction is the direction orthogonal to both the traveling direction of the light beam group B and the main scanning direction.

[0038] The polygon mirror 54 has six reflecting surfaces 54A provided at an equal distance from the rotation axis k, and each reflecting surface 54A rotates at a constant speed around the rotation axis k. The polygon mirror 54 reflects the light beam group B that has passed through the coupling lens CL and deflects it in the main scanning direction.

[0039] The first scanning lens 55 scans the light beam group B scanned at a constant angular velocity by the polygon mirror 54 at a constant speed in the main scanning direction on the surface of the photoreceptor 61.

[0040] The reflecting mirror 56 reflects the light beam group B that has passed through the first scanning lens 55 toward the second scanning lens 57.

[0041] The second scanning lens 57 refracts the light beam group B to converge it in the sub-scanning direction in order to correct the tilt of the polygon mirror 54, and forms an image on the scanned surface of the surface of the photoreceptor 61.

[0042] In the scanning optical device 5 configured as described above, the light beam groups BM, BC, BY, and BK from the light source devices 51M, 51K, 51Y, and 51C, specifically from the semiconductor lasers LDM, LDC, LDY, and LDK, are deflected and scanned in the main scanning direction by the polygon mirror 54. The light beam groups BM, BC, BY, and BK deflected by the polygon mirror 54 pass through the first scanning lens 55 respectively and are reflected by the reflecting mirror 56. After the reflected light beam groups BM, BC, BY, and BK pass through the second scanning lens 57 and the exposure openings formed on the bottom surface of the scanner frame 50, they scan and expose the scanned surfaces of the photoreceptors 61M, 61K, 61Y, and 61C respectively.

[0043] <Laser substrate> Also, as shown in FIGS. 2 to 5, a laser substrate 100, which is a circuit board for controlling the lighting of the first to fourth semiconductor lasers LDM, LDC, LDY, and LDK, is provided on the outer wall of the scanner frame 50, and the laser substrate 100 is supported by the scanner frame 50. Specifically, the laser substrate 100 is supported by the frame body 50A of the scanner frame 50 together with the deflector.

[0044] As shown in FIGS. 5, 7(a), and 7(b), the scanner frame 50 has a laser holder 171 into which the first semiconductor laser LDM and the third semiconductor laser LDY are press-fitted, and a laser holder 172 into which the second semiconductor laser LDC and the fourth semiconductor laser LDK are press-fitted. The laser holders 171 and 172 are fixed to the frame body 50A by the third screws S3 respectively.

[0045] As shown in FIG. 7(b), the second semiconductor laser LDC is arranged side by side with the first semiconductor laser LDM in the longitudinal direction of the laser substrate 100. The third semiconductor laser LDY is arranged side by side with the first semiconductor laser LDM in the short-side direction of the laser substrate 100. The fourth semiconductor laser LDK is arranged side by side with the second semiconductor laser LDC in the short-side direction of the laser substrate 100 and is arranged side by side with the third semiconductor laser LDY in the longitudinal direction of the laser substrate 100. The first semiconductor laser LDM has a first lead terminal TM. The second semiconductor laser LDC has a second lead terminal TC. The third semiconductor laser LDY has a third lead terminal TY. The fourth semiconductor laser LDK has a fourth lead terminal TK.

[0046] As shown in FIG. 6, the laser substrate 100 has holes 101M, 101C, 101Y, and 101K. As shown in FIGS. 5, 6, 7(a), and 7(b), the first lead terminal TM of the first semiconductor laser LDM is inserted into the hole 101M. The second lead terminal TC of the second semiconductor laser LDC is inserted into the hole 101C. The third lead terminal TY of the third semiconductor laser LDY is inserted into the hole 101Y. The fourth lead terminal TK of the fourth semiconductor laser LDK is inserted into the hole 101K.

[0047] <Configuration for positioning on the scanner frame side> As shown in FIGS. 5, 7(a), 7(b), and 8, the scanner frame 50 has a first positioning portion 151 for positioning the laser substrate 100 in the longitudinal direction, a second positioning portion 152 for positioning the laser substrate 100 in the lateral direction, and a third positioning portion 153 for positioning the laser substrate 100 in the lateral direction. Further, the scanner frame 50 has a contact portion 170 that protrudes in a direction penetrating the laser substrate 100 and contacts an end portion of the laser substrate 100 in the lateral direction. The contact portions 170 are respectively arranged on one side and the other side of the first positioning portion 151 in the longitudinal direction of the laser substrate 100. The laser substrate 100 has a contacted portion 114 that contacts the contact portion 170. The contacted portion 114 is arranged at a position recessed from one end of the laser substrate 100 in the lateral direction.

[0048] As shown in FIGS. 5, 8(a), and 8(b), the first to third positioning portions 151, 152, and 153 respectively protrude in a direction penetrating the laser substrate 100.

[0049] In this example, the first positioning portion 151 is substantially rectangular and has a positioning surface 151a extending in the short direction along the groove. As shown in FIG. 7(b), the position of the first positioning portion 151 in the longitudinal direction of the laser substrate 100 is between the positions of the first semiconductor laser LDM and the second semiconductor laser LDC in the longitudinal direction, but it does not have to be exactly the midpoint between these two positions.

[0050] The second positioning portion 152 and the third positioning portion 153 are respectively arranged on one side and the other side sandwiching the first and second semiconductor lasers LDM and LDC in the longitudinal direction of the laser substrate 100. The positions of the second positioning portion 152 and the third positioning portion 153 in the short direction of the laser substrate 100 are between the positions of the first and second semiconductor lasers LDM and LDC in the short direction and the positions of the third and fourth semiconductor lasers LDY and LDK in the short direction, but they do not have to be exactly the midpoint between these two short-direction positions.

[0051] The second positioning portion 152 and the third positioning portion 153 each have a substantially cylindrical shape and an attracting shape in which the tip side of the cylinder becomes thinner. Further, each of the second and third positioning portions 152 and 153 integrally includes a rib portion 160 for strength reinforcement on the base side of the substantially cylindrical shape (see also FIG. 9(b)).

[0052] <Configuration for positioning on the laser substrate side> As shown in FIG. 6, the laser substrate 100 includes a first to-be-positioned portion 111 positioned by the first positioning portion 151 passing through it, a second to-be-positioned portion 112 positioned by the second positioning portion 152 passing through it, and a third to-be-positioned portion 113 positioned by the third positioning portion 153 passing through it.

[0053] In this example, the first to-be-positioned portion 111 is configured in a notch shape. In particular, in this example, the first to-be-positioned portion 111 is a groove extending in the short direction of the laser substrate 100, and one end of the groove in the short direction is open. Further, in this example, the second positioned part 112 and the third positioned part 113 are each configured in a notch shape, but they may be configured as holes.

[0054] The laser substrate 100 is attached to the scanner frame 50 by fastening a plurality of screws including the first screw S1 and the second screw S2 to a plurality of screw holes including the corresponding screw holes U1, U2 of the scanner frame 50. As shown in FIG. 9(a), which is an enlarged view of part C in FIG. 8(b), an elastic member 180 made of, for example, a ring-shaped urethane foam is interposed between the head of each of the first screw S1 and the second screw S2 and the laser substrate 100.

[0055] As shown in FIGS. 7(a) and 7(b), the first screw S1 and the second screw S2 are respectively arranged on one side and the other side of the first and second semiconductor lasers LDM, LDC with the longitudinal direction of the laser substrate 100 interposed therebetween. Further, the first screw S1 and the second screw S2 are arranged on a straight line J connecting the second positioning part 152 and the third positioning part 153. Note that it is not necessary for the centers of the first screw S1 and the second screw S2 to be exactly on the straight line J, and it is sufficient that the heads of the first screw S1 and the second screw S2 are located on the straight line J.

[0056] <Effects of the Embodiment> As described above, in the scanning optical device 5 of the present embodiment, in the scanner frame 50, a first positioning part 151 for positioning the laser substrate 100 in the longitudinal direction, and a second positioning part 152 and a third positioning part 153 for positioning in the short-side direction are provided. When attaching the laser substrate 100 to the scanner frame 50, first, the first positioning portion 151 is used to position the laser substrate 100 in the longitudinal direction. After that, with the longitudinal direction being positioned, the laser substrate 100 is positioned in the short-side direction in the order of either one of the second positioning portion 152 and the third positioning portion 153, and then the other one. In such a process, the laser substrate 100 can be attached to the scanner frame 50 while regulating the position of the laser substrate 100 by the first to third positioning portions 153. Therefore, the first to fourth lead terminals TM, TC, TY, TK of the first to fourth semiconductor lasers LDM, LDC, LDY, LDK can be easily inserted into the holes 101M, 101C, 101Y, 101K of the laser substrate 100 respectively.

[0057] Also, particularly in this embodiment, the position of the first positioning portion 151 in the longitudinal direction is between the position of the first semiconductor laser LDM in the longitudinal direction and the position of the second semiconductor laser LDC in the longitudinal direction. Thereby, the distance from the first positioning portion 151 to the first semiconductor laser LDM and the distance from the first positioning portion 151 to the second semiconductor laser LDC can be made substantially the same. As a result, while positioning the laser substrate 100 in the longitudinal direction by the first positioning portion 151, the first and second lead terminals TM, TC of the first and second semiconductor lasers LDM, LDC respectively can be inserted into the holes 101M, 101C of the laser substrate 100 almost simultaneously. Further, even when there is a difference in the coefficient of thermal expansion between the laser substrate 100 and the scanner frame 50, since the distances from the first positioning portion 151 to the first semiconductor laser LDM or the second semiconductor laser LDC are substantially the same as each other as described above, the adverse effects due to the thermal expansion difference can be reduced.

[0058] In particular, in this embodiment, the positions of the second positioning portion 152 and the third positioning portion 153 in the short side direction are between the position of the first semiconductor laser LDM in the short side direction and the position of the third semiconductor laser LDY in the short side direction. As a result, the distance from the second and third positioning portions 152, 153 to the first semiconductor laser LDM and the distance from the second and third positioning portions 152, 153 to the third semiconductor laser LDY can be made substantially the same. As a result, while positioning the laser substrate 100 in the short side direction by the second positioning portion 152 and the third positioning portion 153, the first and third lead terminals TM and TY of the first and third semiconductor lasers LDM and LDY can be inserted into the holes 101M and 101Y of the laser substrate 100 almost simultaneously. Also, even when there is a difference in the coefficient of thermal expansion between the laser substrate 100 and the scanner frame 50, since the distance from the second and third positioning portions 152, 153 to the first semiconductor laser LDM and the distance from the second and third positioning portions 152, 153 to the third semiconductor laser LDY are substantially the same as described above, the adverse effects due to the thermal expansion difference can be reduced.

[0059] Also, when there is a difference in the coefficient of thermal expansion between the laser substrate 100 and the scanner frame 50, the influence becomes more prominent at a portion farther from the second positioning portion 152 and the third positioning portion 153, and stress is generated. In particular, in this embodiment, since the first screw S1 and the second screw S2 for fastening are located between the second positioning portion 152 and the third positioning portion 153 that are separated from each other in the longitudinal direction, at least in the short side direction, the above influence can be reduced, and the adverse effects due to the generation of stress can be suppressed.

[0060] In particular, in this embodiment, the laser substrate 100 is not directly pressed and fastened by the first screw S1 and the second screw S2, but the elastic member 180 is interposed therebetween. As a result, even when there is a difference in the coefficient of thermal expansion between the laser substrate 100 and the scanner frame 50, the displacement between the laser substrate 100 and the scanner frame 50 due to the thermal expansion difference can be released by the sliding on the surface of the elastic member 180, and the generation of stress can be suppressed.

[0061] Further, in particular, in the present embodiment, the first positioned portion 111 is a groove in the short-side direction. Thereby, when the laser substrate 100 is attached to the scanner frame 50, a degree of freedom in the short-side direction can be provided. As a result, when attaching the laser substrate 100, it is easy to surely insert the lead terminal of the first semiconductor laser LDM into the hole of the laser substrate 100.

[0062] Further, in particular, in the present embodiment, the first positioning portion 151 has a positioning surface 151a extending in the short-side direction. Thereby, when inserted into the groove-shaped first positioned portion 111 of the laser substrate 100, rotation of the laser substrate 100, that is, rotation about an axis orthogonal to the surface of the laser substrate 100, can be restricted. As a result, attachment of the laser substrate 100 to the scanner frame 50 becomes even easier.

[0063] Further, in particular, in the present embodiment, one end of the first positioned portion 111 having a groove shape in the short-side direction is open. Thereby, the first positioning portion 151 can be easily engaged with the first positioned portion 111.

[0064] Further, in particular, in the present embodiment, the second positioning portion 152 has a substantially cylindrical shape. Thereby, handling and engagement when attaching the laser substrate 100 to the scanner frame 50 are easy.

[0065] Further, in particular, in the present embodiment, the second positioning portion 152 integrally includes a rib portion 160 for strength reinforcement on the base side having the substantially cylindrical shape. Thereby, the strength can be increased and the rigidity can be increased compared to the case where the second positioning portion 152 is merely a cylindrical shape.

[0066] Further, in particular in this embodiment, the scanner frame 50 has a contact portion 170 that protrudes in a direction penetrating the laser substrate 100 and contacts the end portion of the laser substrate 100 in the short-side direction. Thereby, when the laser substrate 100 is attached to the scanner frame 50, the contact portion 170 contacts the end portion of the laser substrate 100 to perform guiding, so that rotation about an axis orthogonal to the surface of the laser substrate 100 can be restricted.

[0067] Further, in particular in this embodiment, the scanner frame 50 includes a frame body 50A that supports the deflector and the laser substrate 100, laser holders 171 and 172 into which semiconductor lasers LDM, LDC, LDY, and LDK are press-fitted, and a third screw S3 that fixes the laser holders 171 and 172 to the frame body 50A of the scanner frame 50. Thereby, in this embodiment, unlike the conventional method of first assembling the holder and the laser substrate, in the assembling process, first, the semiconductor lasers LDM, LDC, LDY, and LDK are press-fitted into the laser holders 171 and 172, and the laser holders 171 and 172 are fixed to the frame body 50A of the scanner frame 50 with the third screw S3. Thereafter, the laser substrate 100 can be smoothly attached to the scanner frame 50, that is, the lead terminals TM, TC, TY, and TK can be inserted into the holes 101M, 101C, 101Y, and 101K of the laser substrate 100 and soldered.

[0068] <Modification> Note that the present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit and technical idea thereof.

[0069] That is, in the above, the case where the present invention is applied to a color printer has been described as an example, but the present invention can also be applied to other image forming apparatuses such as a multifunction machine and a copying machine.

[0070] Further, in the above, the polygon mirror 54 has been shown, but as the optical deflector, a vibrating mirror, so-called a galvano mirror, can also be adopted. Also, in the above description, the direct transfer method of transporting the paper and transferring the developer image onto the paper during the image forming process has been described as an example, but it is not limited to this. That is, a so-called intermediate transfer method may be used in which the developer image from the photoreceptor 61 is transferred to the transfer belt during the image forming process, and the developer image on the transfer belt is transferred to the paper that is separately transported.

[0071] Also, in addition to what has already been described above, the methods according to the above-described embodiments and each modification example may be appropriately combined and used.

[0072] Although not exemplified one by one, the present invention may be implemented with various modifications within the scope not departing from its gist.

Explanation of Reference Numerals

[0073] 5 Scanning Optical Device 50 Scanner Frame 50A Frame Body 54 Polygon Mirror 100 Laser Substrate 101M Hole 101C Hole 101K Hole 101Y Hole 111 First Positioning Portion 112 Second Positioning Portion 113 Third Positioning Portion 151 First Positioning Portion 151a Positioning Surface 152 Second Positioning Portion 153 Third Positioning Portion 160 Rib Portion 170 Contact Portion 171 Laser Holder 172 Laser Holder 180 Elastic Member LDM First Semiconductor Laser LDC Second Semiconductor Laser LDY Third Semiconductor Laser S1 First Screw S2 Second Screw S3 Third Screw TM First Lead Terminal (corresponding to an example of a lead terminal) TC Second Lead Terminal TY Third Lead Terminal

Claims

1. a first semiconductor laser having lead terminals; a deflector that deflects and scans light from the first semiconductor laser; a laser substrate that has a hole into which the lead terminals of the first semiconductor laser are inserted and controls the first semiconductor laser; a scanner frame that supports the first semiconductor laser, the deflector, and the laser substrate; comprising: the scanner frame includes: a first positioning portion that protrudes in a direction penetrating the laser substrate and positions the laser substrate in the longitudinal direction; a second positioning portion that protrudes in a direction penetrating the laser substrate and positions the laser substrate in the short-side direction; a third positioning portion that protrudes in a direction penetrating the laser substrate and positions the laser substrate in the short-side direction; having: the second positioning portion and the third positioning portion are respectively disposed on one side and the other side of the first semiconductor laser in the longitudinal direction of the laser substrate with the first semiconductor laser interposed therebetween; A scanning optical device characterized by the above.

2. having a second semiconductor laser disposed side by side with the first semiconductor laser in the longitudinal direction of the laser substrate; the position of the laser substrate in the longitudinal direction of the first positioning portion is between the position of the first semiconductor laser in the longitudinal direction and the position of the second semiconductor laser in the longitudinal direction; The scanning optical device according to claim 1, characterized by the above.

3. having a third semiconductor laser disposed side by side with the first semiconductor laser in the short-side direction of the laser substrate; the positions of the second positioning portion and the third positioning portion in the short-side direction are between the position of the first semiconductor laser in the short-side direction and the position of the third semiconductor laser in the short-side direction; The scanning optical device according to claim 1, characterized by the above.

4. having a first screw and a second screw for fastening the laser substrate to the scanner frame, the first screw and the second screw are arranged on a straight line connecting the second positioning portion and the third positioning portion, and the first screw and the second screw are respectively disposed on one side and the other side of the first semiconductor laser in the longitudinal direction of the laser substrate with the first semiconductor laser interposed therebetween; The scanning optical device according to claim 1, characterized by the above.

5. having an elastic member interposed between the head of the first screw and the laser substrate; The scanning optical device according to claim 4, characterized by the above.

6. The laser substrate has a first part to be positioned which is positioned by the first positioning part passing therethrough. The first part to be positioned is a groove extending in the short-side direction. The scanning optical device according to claim 1, characterized in that.

7. The first positioning part has a positioning surface extending in the short-side direction along the groove. The scanning optical device according to claim 6, characterized in that.

8. One end of the groove in the short-side direction is open. The scanning optical device according to claim 6, characterized in that.

9. The second positioning part has a substantially cylindrical shape. The scanning optical device according to claim 1, characterized in that.

10. The second positioning part integrally includes a rib part for strength reinforcement on the base part side of the substantially cylindrical shape. The scanning optical device according to claim 9, characterized in that.

11. The scanner frame has a contact part that protrudes in a direction passing through the laser substrate and contacts an end part of the laser substrate in the short-side direction. The scanning optical device according to claim 1, characterized in that.

12. The scanner frame includes a frame body that supports the deflector and the laser substrate, a laser holder into which the first semiconductor laser is press-fitted, and a third screw that fixes the laser holder to the frame body. The scanning optical device according to claim 1, characterized by having.

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