JP2011017854A - Light source device and optical scanner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the misalignment involved in fixing a coupling lens to an adhering member which holds a light source device with an adhesive.SOLUTION: The light source device 120 includes: a semiconductor laser (light-emitting element) 121; the coupling lens 122; and the holder (holding member) 123. The holder 123 holds the semiconductor laser 121 and the coupling lens 122. The holder 123, which holds the semiconductor laser and the coupling lens 122, has a fixed surface 123E that is opposite to a surface of the coupling lens 122 facing to the semiconductor laser in a direction of an optical axis of the coupling lens. A part of the surface of the coupling lens 122 facing to the semiconductor laser is bonded to the fixed surface 123E.

Description

  The present invention relates to a light source device and an optical scanning device.

  In general, an image forming apparatus such as a laser printer is provided with an optical scanning device as a part of an optical system for forming an electrostatic latent image on a photosensitive member. The optical scanning device includes a light source device, a deflector that deflects the light beam emitted from the light source device and scans the surface of the photosensitive member (a surface to be scanned), and the light beam deflected by the polarizer. And an imaging optical system for forming an image.

  As such a light source device for an optical scanning device, a light source device in which a coupling lens is positioned on a protrusion provided on a holding member for holding a light emitting element such as a semiconductor laser and fixed by an ultraviolet curable adhesive is known. (Patent Document 1).

JP 2002-31773 A

  In the light source device described in Patent Document 1 (see FIG. 1 and FIG. 2), since the adhesive is applied to the peripheral end surface of the coupling lens and only to the lower portion thereof, the adhesive is cured and contracted. Therefore, there is a problem that the optical axes of the light emitting element and the coupling lens are likely to be shifted (in this case, particularly in the vertical direction), and accurate optical axis alignment is difficult.

  The inventor who paid attention to this problem is a research for providing a light source device capable of suppressing a shift when the coupling lens is fixed to the holding member by adhesion, and an optical scanning device including such a light source device. The present invention was invented in the process of.

  A light source device as one embodiment of the present invention includes a light emitting element, a coupling lens that collects a light beam emitted from the light emitting element, and a holding member that holds the light emitting element and the coupling lens. The holding member has a fixed surface facing the light emitting element side surface of the coupling lens in the optical axis direction of the coupling lens, and a part of the surface of the coupling lens on the light emitting element side is It is bonded to the fixed surface.

  According to the light source device, since the surface of the coupling lens on the light emitting element side is bonded to the fixed surface of the holding member facing in the optical axis direction, the displacement of the coupling lens due to the curing shrinkage of the adhesive is mainly coupled. It becomes the optical axis direction of the lens, and the deviation of the optical axes of the light emitting element and the coupling lens is suppressed. An optical scanning device including such a light source device accurately forms an image on a surface to be scanned because the light beam emitted from the light emitting element is incident on the scanning optical system and the imaging optical system with high accuracy. be able to.

1 is a cross-sectional view of a laser printer as an example of an image forming apparatus. It is a top view of an optical scanning device. It is sectional drawing of an optical scanning device. It is a disassembled perspective view of a light source device. (A) is a top view inside the light source device shown with the shielding member removed, and (b) is a longitudinal sectional view of the light source device shown in FIG. It is a front view for demonstrating the protection part shape of a holder (holding member). It is the perspective view seen from the LD attachment part side of a holder. (A) is the perspective view seen from the aperture side of the light source device, (b) is the perspective view seen from the circuit board back side of the light source device. It is a perspective view which shows the process of positioning and fixing a coupling lens to a holder. It is a perspective view which shows the process of electrically connecting the semiconductor laser (light emitting element) hold | maintained at the holder, and a circuit board.

  Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. In the following description, first, a schematic configuration of the laser printer 1 as an example of an image forming apparatus will be described, and then configurations related to characteristic portions of the optical scanning device 100 and the light source device 120 will be described in detail.

<Schematic configuration of laser printer>
As shown in FIG. 1, a laser printer 1 includes a paper feeding unit 3 that supplies paper P, an optical scanning device 100, a process cartridge 5 that transfers a toner image onto the paper P, and paper. It mainly includes a fixing device 8 that thermally fixes the toner image transferred onto P.

  Hereinafter, in describing the arrangement and operation of the components of the laser printer 1, the direction is displayed in a direction based on the user who uses the laser printer 1. That is, the right side in FIG. 1 is “front”, the left side is “rear”, the front side is “left”, and the back side is “right”. Also, the vertical direction in FIG.

  The paper feed unit 3 is provided in the lower part of the main casing 2, and includes a paper feed tray 31 that accommodates the paper P, a paper pressing plate 32 that lifts the front side of the paper P, a paper feed roller 33, and a paper feed pad 34. The paper dust removing rollers 35 and 36 and the registration roller 37 are mainly provided. The paper P in the paper feed tray 31 is brought close to the paper feed roller 33 by the paper pressing plate 32 and separated one by one by the paper feed roller 33 and the paper feed pad 34, and the paper dust removing rollers 35 and 36 and the registration roller 37. Then, it is conveyed toward the process cartridge 5.

  The optical scanning device 100 is disposed in the upper part of the main casing 2 and emits laser light (light beam: see chain line) based on image data, and exposes the surface of the photosensitive drum 61 as an example of a photosensitive member to statically. An electrostatic latent image is formed. A detailed configuration of the optical scanning device 100 will be described later.

  The process cartridge 5 is disposed below the optical scanning device 100 and is configured to be detachably attached to the main body casing 2 through an opening formed when the front cover 21 provided in the main body casing 2 is opened. . The process cartridge 5 includes a drum unit 6 and a developing unit 7.

  The drum unit 6 mainly includes a photosensitive drum 61, a charger 62, and a transfer roller 63 in a drum case 60. The developing unit 7 is configured to be detachably attached to the drum unit 6. A developing roller 71, a supply roller 72, a layer thickness regulating blade 73, and toner are accommodated in the developing case 70. The toner container 74 is mainly provided.

  In the process cartridge 5, the surface of the photosensitive drum 61 is uniformly charged by the charger 62 and then exposed by high-speed scanning of the laser beam from the optical scanning device 100, whereby an image is formed on the photosensitive drum 61. An electrostatic latent image based on the data is formed. Further, the toner in the toner container 74 is supplied to the developing roller 71 via the supply roller 72 and enters between the developing roller 71 and the layer thickness regulating blade 73 to form a thin layer with a certain thickness. Supported on.

  The toner carried on the developing roller 71 is supplied from the developing roller 71 to the electrostatic latent image formed on the photosensitive drum 61. As a result, the electrostatic latent image is visualized and a toner image is formed on the photosensitive drum 61. Thereafter, the sheet P is conveyed between the photosensitive drum 61 and the transfer roller 63, whereby the toner image on the photosensitive drum 61 is transferred onto the sheet P.

  The fixing device 8 is provided behind the process cartridge 5, and includes a heating roller 81, a pressure roller 82 that sandwiches the paper P between the heating roller 81, and a conveyance roller 83 that conveys the paper P after fixing. Mainly prepared. The toner transferred onto the paper P is thermally fixed by the paper P being conveyed between the heating roller 81 and the pressure roller 82. The sheet P on which the toner image has been thermally fixed is conveyed to the discharge path 23 by the conveyance roller 83 and is discharged from the discharge path 23 onto the discharge tray 22 by the discharge roller 24.

<Detailed configuration of optical scanning device>
Next, a detailed configuration of the optical scanning device 100 will be described. As shown in FIGS. 2 and 3, the optical scanning device 100 is an example of a light source device 120 and a deflector that deflects laser light (light beam) emitted from the light source device in a resin scanner frame 110. Polygon mirror 130 and an image forming optical system for forming an image of the laser beam deflected by the polygon mirror 130 on the surface (scanned surface) of the photosensitive drum 61. In the present embodiment, the imaging optical system includes an fθ lens 150, a cylindrical lens 160, and mirrors 170 and 180.

  The light source device 120 is a device that emits a laser beam (light beam) for exposing the surface of the photosensitive drum 61 in accordance with image data. A detailed configuration of the light source device 120 will be described later.

  The polygon mirror 130 is disposed on the downstream side of the light source device 120, and a reflection mirror is formed on each side surface of the hexagonal prism. The polygon mirror 130 reflects the laser light from the light source device 120 while rotating at high speed, and deflects it in the main scanning direction and scans it at an equiangular speed.

  As shown in FIG. 3, the fθ lens 150 is a scanning lens that is disposed on the downstream side of the polygon mirror 130 and through which the laser light deflected and scanned by the polygon mirror 130 passes. The fθ lens 150 converts the laser beam scanned by the polygon mirror 130 at a constant angular speed so as to scan at a constant speed.

  The mirror 170 is disposed on the downstream side of the fθ lens 150, reflects the laser light that has passed through the fθ lens 150, turns back the optical path of the laser light, and directs it toward the cylindrical lens 160.

  The cylindrical lens 160 is a scanning lens that is disposed on the downstream side of the mirror 170 and above the fθ lens 150 and through which the laser light reflected by the mirror 170 passes. The cylindrical lens 160 refracts the laser light and converges it in the sub-scanning direction.

  The mirror 180 is disposed on the downstream side of the cylindrical lens 160, reflects the laser light that has passed through the cylindrical lens 160, and directs it toward the photosensitive drum 61 (see FIG. 1). Specifically, the laser light reflected by the mirror 180 passes through the glass plate 190 attached to the scanner frame 110 and is scanned at high speed on the surface of the photosensitive drum 61.

  The scanner frame 110 is a frame formed of a resin in a substantially box shape, and the light source device 120 (see FIG. 2), the fθ lens 150, the cylindrical lens 160, the mirrors 170 and 180, and the like are fixed. The scanner frame 110 is attached to the metal frame 200.

  The metal frame 200 is a frame formed by bending a metal plate. The resin scanner frame 110 is reinforced by being attached to the metal frame 200. By attaching the metal frame 200 to the main casing 2, the optical scanning device 100 is positioned and fixed to the upper part in the main casing 2 (see FIG. 1).

  As shown in FIG. 1, the main casing 2 supports a metal frame 200 on which the optical scanning device 100 is disposed and a photosensitive drum 61. The photosensitive drum 61 is supported in a state of being positioned below the optical scanning device 100 in the main body casing 2 via a case (drum case 60) of the attached process cartridge 5.

<Detailed configuration of light source device>
Next, a detailed configuration of the light source device 120 will be described. As illustrated in FIGS. 4 and 5, the light source device 120 includes a semiconductor laser 121 as an example of a light emitting element, a coupling lens 122, and a holding member that holds the semiconductor laser 121 and the coupling lens 122. A holder 123, a circuit board 124, and a shielding member 125 are mainly provided.

  In the following description, the downstream side of the traveling direction of the laser light emitted from the light source device 120 is “front”, the upstream side is “rear”, and the upper, lower, left, and right are as appropriate. Based on the direction shown in FIG.

  The semiconductor laser 121 is a known laser light source (laser diode: LD) that emits light by injecting carriers into a semiconductor pn junction. The semiconductor laser 121 is electrically connected to a drive unit 124A mounted on the circuit board 124. When the drive unit 124A receives a light emission control signal based on image data to be formed, the drive unit 124A drives the semiconductor laser 121 in accordance with the control signal.

  The coupling lens 122 condenses the divergent laser light (light beam) emitted from the semiconductor laser 121 into a parallel or substantially parallel light beam and couples it to the subsequent (downstream) optical system (collimator). Lens). When the laser light that has passed through the coupling lens 122 passes through an aperture 126 (see FIG. 8A) formed in a shielding member 125, which will be described later, the range of the beam bundle cross section is restricted and the polygon mirror 130 ( Go to Figure 2).

  As shown in FIGS. 4 to 7, the holder 123 is a member formed so as to hold the semiconductor laser 121 at the rear end and the coupling lens 122 at the front end in a state of alignment adjustment. (Insulator) is integrally formed. Specifically, the holder 123 has a substantially rectangular box shape whose main body is opened on the lower side, a lens mounting portion on which a coupling lens is mounted on the front side, and an LD on which a semiconductor laser is mounted on the rear side. A mounting portion is formed.

  An opening 123C and an opening 123F are provided in the LD attachment portion and the lens attachment portion of the holder 123, respectively. Therefore, the laser light emitted from the semiconductor laser 121 passes through the inside of the holder 123 from the opening 123C, passes through the opening 123F, and enters the coupling lens 122. Fastening portions 123 </ b> D having screw insertion holes for attaching the holder 123 to the scanner frame 110 are formed on the left and right side wall portions of the holder 123 so as to protrude left and right.

  As shown in FIG. 7, a socket portion 123 </ b> A having a shape in which the light emitting surface side end portion of the semiconductor laser 121 can be inserted from the rear of the holder 123 is formed at the rear end portion (LD mounting portion) of the holder 123. Notches 123B for holding the adhesive are provided at the upper and lower portions of the opening periphery of the socket 123A. The opening 123C of the LD mounting portion is formed at the bottom (front) center of the socket portion 123A.

  As shown in FIGS. 4 and 5, a fixing surface 123 </ b> E to which the coupling lens 122 is fixed (adhered) at the peripheral edge of the surface on the semiconductor laser 121 side is provided at the front end portion (lens mounting portion) of the holder 123. A protective portion 123G is formed around the fixed surface 123E so as to surround the coupling lens 122 with a space therebetween. Note that, in FIGS. 5 and 6 and FIGS. 9 and 10 to be referred to later, the adhesive for bonding the coupling lens 122 is exaggerated regardless of the actual size ratio.

  The fixed surface 123E is a surface facing the surface on the semiconductor laser 121 side of the coupling lens 122 in the optical axis direction. Specifically, a bulging portion that bulges forward is formed at two left and right sides (positions symmetrical to the optical axis) adjacent to the edge of the opening 123F, and is formed at the front end of the bulging portion. The flat surface portion becomes the fixed surface 123E. The distance between the two fixing surfaces 123E is such that the portion of the coupling lens 122 bonded to the fixing surface 123E is outside the region through which the laser light emitted from the semiconductor laser 121 is transmitted.

  Two protective parts 123G are provided at positions that partially cover the periphery of the side surface when the coupling lens 122 is attached. The protection unit 123G is separated from the coupling lens 122 in a direction orthogonal to the optical axis of the coupling lens 122, and is ahead of the laser light emission side surface of the coupling lens 122 (downstream in the laser light traveling direction). Protruding.

  As shown in FIG. 6, the distance L1 between the side surface of the coupling lens 122 and the protection part 123G is larger than the radius R of the coupling lens 122 (L1> R). These two protection parts 123G are each formed in a substantially U shape when viewed in the optical axis direction of the coupling lens 122. Note that the front end portion of the protruding protective portion 123G is in a plane perpendicular to the optical axis of the coupling lens 122, and when the front end portion faces downward, the front end portion is used as a support leg portion, and the holder 123 is a horizontal surface. It has a shape that can be stably placed on top.

  In this embodiment, the small protrusion 123K is provided on the plane which comprises the front-end part of the protection part 123G. This is used to position and arrange the holder 123 on a dedicated workbench provided with a corresponding positioning hole in a process of soldering the circuit board 124 to a lead pin of the semiconductor laser 121 described later. The small protrusion 123K is an option provided only when soldering using such a dedicated workbench. The small protrusion 123 </ b> K does not constitute an end portion having a function as a “support leg” of the holder 123.

  An open portion 123H (see FIG. 5A) that exposes the side surface of the coupling lens 122 is formed between the two protective portions 123G. When the coupling lens 122 is fixed to the fixing surface 123E of the holder 123, the opening 123H holds a side surface of the coupling lens 122 and a predetermined position near the fixing surface 123E by a chuck 300 (see FIG. 9) described later. It is for enabling positioning.

  Therefore, the distance L2 between the protection parts 123G separated by the open part 123H is larger than the diameter D of the coupling lens 122 so as not to interfere with the chuck 300 at the time of positioning in the direction orthogonal to the optical axis direction of the coupling lens 122. It is designed to be slightly larger (L2> D). In particular, in the present embodiment, the open portion 123H extends to the rear (toward the semiconductor laser 121) than the surface of the coupling lens 122 on the semiconductor laser 121 side, so that the optical axis direction of the coupling lens 122 by the chuck 300 is increased. Can be easily and smoothly implemented without being obstructed by the protective portion 123G.

  Circuits and elements such as a drive unit (driver chip) 124A for driving the semiconductor laser 121 are mounted on the surface of the circuit board 124, as shown in FIGS. The semiconductor laser 121 is electrically connected to the drive unit 124A by being soldered to the circuit board 124 (see reference numeral 124c in FIG. 10). In addition, the grounding portion 124 </ b> B is provided around the two cutout portions that engage with the shielding member 125 on the back side of the circuit board 124.

  The shielding member 125 is formed by pressing a metal plate. As shown in FIGS. 5B and 8, the shielding member 125 is provided with an aperture 126 that extends to cover the front end of the holder 123. The first wall 125A, the second wall 125B extending from the upper end of the first wall 125A so as to cover the coupling lens 122 and the semiconductor laser 121, and the rear end of the second wall 125B. To a third surface extending so as to cover a part of the back surface of the circuit board 124 (the surface opposite to the surface on which the circuits and elements are mounted) (at least the substantially central portion including the portion where the semiconductor laser is mounted). Wall part 125C.

  Further, the shielding member 125 has four side band portions 125 </ b> D that extend downward along the side wall of the holder 123 from two front and rear portions of the left and right edges of the second wall portion 125 </ b> B. The side band portion 125 </ b> D is provided with openings at positions corresponding to the four fitting protrusions formed on the side wall portion of the holder 123, and the shielding member 125 is snap-fitted to the holder 123 using this. And fixed.

  The shielding member 125 is engaged with the notch portion of the circuit board 124 at two positions behind the side band portion 125D on the rear side, and is soldered and fixed to the grounding portion 124B provided on the back side of the circuit board 124.

<Manufacturing process of light source device>
Next, the manufacturing process of the light source device 120 according to the present embodiment will be described.
(Step 1) The holder 123 is integrally molded by injecting the heat-melted resin material into a dedicated injection mold.

  (Step 2) The shielding member 125 is formed by subjecting the sheet metal to a press machine and processing such as shearing, punching, and bending.

  (Step 3) The semiconductor laser 121 is inserted into the socket portion 123A formed at the rear end portion (LD mounting portion) of the holder 123, and is fixed with an adhesive filled in the notch portion 123B of the socket portion 123A.

  (Step 4) An adhesive made of an ultraviolet curable resin is applied to the fixing surface 123E formed on the front end portion (lens mounting portion) of the holder 123, and the coupling lens 122 held by the chuck 300 is positioned. After the positioning is completed, as shown in FIG. 9, the adhesive is cured by irradiating ultraviolet rays (UV) with an ultraviolet irradiator 400, and after the curing is completed, the chuck 300 is retracted from the coupling lens 122.

  (Step 5) As shown in FIG. 10, the holder 123 is placed on the work table with its rear end facing upward, and the circuit board 124 is soldered to the lead pins of the semiconductor laser 121 (see reference numeral 124c). In the illustrated embodiment, the small protrusion 123K formed on the front end portion of the holder 123 is fitted into the positioning hole formed on the workbench so that the holder 123 can be stably prevented from being displaced on the workbench. Placed.

  (Step 6) With the semiconductor laser 121 soldered to the circuit board 124, the shielding member 125 is snap-fitted and fixed to the holder 123 using the side band portion 125D.

  (Step 7) The shielding member 125 is soldered to the circuit board 124 at the two ground portions 124B shown in FIG. As a result, the shielding member 125 is electrically connected to the ground portion 124B of the circuit board 124 and is physically fixed. As a result, the circuit board 124 is indirectly fixed to the holder 123 through the shielding member 125 snap-fitted to the holder 123.

<Action and effect>
The features and effects of this embodiment and the main advantages (effects) obtained thereby will be described below.
1. Mounting structure of coupling lens to holder According to the present embodiment, the holder 123 has a fixed surface 123E facing the surface of the coupling lens 122 on the semiconductor laser 121 side in the optical axis direction of the coupling lens 122, A part of the surface of the coupling lens 122 on the semiconductor laser 121 side is bonded to the fixed surface 123E.

  As a result, the surface of the coupling lens 122 on the semiconductor laser 121 side is bonded to the fixed surface 123E of the holder 123 facing in the optical axis direction, so that the displacement of the coupling lens 122 due to curing shrinkage of the adhesive is mainly coupled. It becomes the optical axis direction of the lens 122, and the optical axis shift of the semiconductor laser 121 and the coupling lens 122 is suppressed. Therefore, the coupling lens 122 can be more accurately positioned than the conventional mounting structure in which the side surfaces of the lens are bonded.

  In the present embodiment, an ultraviolet curable resin is used for bonding the coupling lens 122 to the holder 123. The UV curable resin has a short time to cure, so the time for holding the lens in an alignment adjusted state can be shortened. Moreover, since there is no whitening phenomenon as seen in an instantaneous adhesive and it does not harden unless it is exposed to ultraviolet rays, it can be applied before adjustment. Therefore, there is an advantage that the degree of freedom in process design is high.

  Further, according to the present embodiment, the fixing surface 123E to which the adhesive is applied is set at two symmetrical positions when viewed from the optical axis direction of the coupling lens 122, and therefore, the adhesive surface is bonded only to one side of the lens side surface. Compared with the prior art mounting structure in which the agent is applied, it is possible to further suppress the deviation of the optical axis.

  The position where the adhesive is applied is preferably set so that the resultant force acting on the coupling lens 122 during curing shrinkage of the photo-curing resin is balanced on a plane perpendicular to the optical axis of the coupling lens 122. Therefore, it is advantageous from the viewpoint of positioning accuracy that the photo-curing resin is applied to a plurality of positions that are rotationally symmetric when viewed from the optical axis direction of the coupling lens 122. It illustrates the simplest form.

  In the present embodiment, a light beam (laser light) on the surface of the coupling lens 122 on the light emitting element (semiconductor laser 121) side is used as a portion to be bonded to the holder 123 (fixed surface 123E) of the coupling lens 122. Since the outside of the transmitting region is effectively used, it can be realized without impairing the function of the lens.

2. Protective structure for holder lens mounting portion In a conventional light source device, when a coupling lens is aligned and fixed to a holder holding a light emitting element, a circuit board for driving the light emitting element is first attached to the holder, and the light emitting element It was soldered to. However, with this method, it has been impossible to simultaneously perform characteristic inspection and alignment adjustment of a single light emitting element. According to this embodiment, since the circuit board 124 can be attached after the coupling lens 122 is aligned and fixed to the holder 123, the characteristic inspection of the single light emitting element can be performed at the time of alignment adjustment.

  When the coupling lens 122 is fixed directly to the holder 123 without using a lens barrel or the like as in this embodiment, the coupling lens 122 after alignment adjustment is exposed on the holder front end side, and the circuit board 124 is attached to the holder rear end. There is a problem that it is difficult to perform the work of soldering to the semiconductor laser 121 on the side. In the present embodiment, the holder 123 is separated from the coupling lens 122 in the direction orthogonal to the optical axis of the coupling lens 122 and is further downstream in the light beam traveling direction than the surface of the coupling lens 122 on the light beam emission side. Therefore, the coupling lens 122 is not exposed.

  Furthermore, according to the present embodiment, as shown in FIG. 10, the end portion of the protective portion 123G extending in the optical axis direction of the coupling lens 122 far from the semiconductor laser 121 is the optical axis of the coupling lens 122. The protection part 123G is configured to be a support leg when the holder 123 is placed on a horizontal plane with the end on the light emitting element (semiconductor laser 121) side facing upward. . Thereby, workability when soldering the semiconductor laser 121 to the circuit board 124 is improved.

  Note that a plurality of protection portions 123G are provided around the side surface of the coupling lens 122, and are arranged so that an opening portion 123H that exposes the side surface of the coupling lens 122 is formed between a pair of adjacent protection portions 123G. Yes. The opening portion 123H is designed such that the distance L2 between a pair of adjacent protection portions 123G separated by the opening portion 123H is larger than the diameter D of the coupling lens 122, and beyond the coupling lens 122, the light emitting element It extends to the (semiconductor laser 121) side. Therefore, when the coupling lens 122 is positioned using the chuck 300 (see FIG. 9), the protection unit 123G does not get in the way.

  The distance L1 between the side surface of the coupling lens 122 and the protection portion 123G is designed to be larger than the radius R of the coupling lens 122. Therefore, it becomes difficult to accidentally attach the adhesive to the protective part 123G during the operation of applying the adhesive to the fixed part. Further, when the ultraviolet curable resin is cured and bonded using the ultraviolet irradiator 400 after positioning the coupling lens 122 (see FIG. 9), it does not interfere with the ultraviolet irradiation.

  In the present embodiment, two protective portions 123G are formed in a substantially U shape when viewed in the optical axis direction of the coupling lens 122. This is an example of a preferable shape as a support leg that enables the holder 123 to be more stably placed on the horizontal work surface when the semiconductor laser 121 is soldered to the circuit board 124.

3. Mounting structure of the circuit board to the holder The screw of about M3, which is usually used for fixing the holder and the circuit board in the conventional light source device, has a large screw head compared to the light emitting element size, which has been a restriction on the miniaturization of the holder. . Further, by providing a screw hole near the center of the circuit board, electromagnetic interference (EMI) shielding performance may be impaired particularly when a circuit or an element is mounted on one side of the circuit board. Furthermore, in order to prevent the holder from being distorted by the tightening torque of the screw, the holder needs to have a strength sufficient to resist the tightening torque.

  According to the present embodiment, since the circuit board 124 is fixed to the holder 123 via the shielding member 125 as described above, it is not necessary to screw the circuit board 124 to the holder 123. Therefore, even when the circuit board 124 is attached after the coupling lens 122 is aligned and fixed to the holder 123 as in the present embodiment, the coupling lens 122 is displaced due to the distortion of the holder 123 due to the screw tightening torque. There is no end. Therefore, an increase in the size of the holder 123 due to the provision of the screwing portion (and the structure for preventing the influence of the fastening torque of the screw) can be avoided. Further, it is possible to prevent the EMI shielding performance from being lowered due to the screw hole.

4). Structure of Shielding Member According to the present embodiment, the shielding member 125 formed of a metal plate has a light emitting element (semiconductor laser) formed by the first wall portion 125A, the second wall portion 125B, and the third wall portion 125C. 121) and at least a part of the circuit board 124. In addition, the shielding member 125 is fixed to the grounding part 124 </ b> B of the circuit board 124. Therefore, the light-emitting element (semiconductor laser 121) that is weak against static electricity, the electronic components of the circuit board 124, and the like are shielded and are not easily affected by electromagnetic waves.

  In particular, when the shielding member having an aperture is a separate member installed in an electrically floating state without being grounded, the influence of the surge current generated there is a light emitting element or an element on a circuit board. Etc. As a result, the light emitting element and the like are gradually destroyed, and there is a problem that the life of the light emitting element and the like is shortened.

  According to the present embodiment, since the shielding member 125 (first wall portion 125A) having the aperture 126 is electrically connected to the grounding portion 124B, the light emitting element (semiconductor laser 121) or the like is destroyed by a surge current. Thus, the durability of the light source device 120 can be improved. Further, the surroundings of the semiconductor laser 121 and the circuit board 124 are shielded by the ground potential by the shielding member 125, and electromagnetic compatibility (EMC) is improved.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment. About a concrete structure, it can change suitably in the range which does not deviate from the meaning of this invention described in the claim.

  In the embodiment, the example in which the shielding member 125 is fixed to the ground portion 124B of the circuit board 124 by soldering has been described. The fixing method suitable for the present invention is not limited to this specific example. For example, other known joining methods that can realize electrical connection as well as fixation, such as welding, brazing, and adhesion using a conductive adhesive, can be employed.

  In the embodiment, the example in which the coupling lens 122 and the fixing surface 123E are bonded with the ultraviolet curable resin is shown. The bonding method that can be used in the practice of the present invention is not limited to this, and for example, bonding using a resin that is cured by light in the visible light region or bonding using other known adhesives may be used. Good.

  In the above embodiment, the case where the portions bonded to the holding member (holder 123) of the coupling lens 122 are two points at symmetrical positions when viewed from the optical axis direction of the coupling lens 122 is illustrated. The invention is not limited to this. For example, a configuration in which three or more spots are bonded can be implemented. In this case, it is preferable that all the adhesion spots are arranged at positions that are rotationally symmetric when viewed from the optical axis direction of the coupling lens 122, but this is not a limitation.

  The specific configuration (shape and size) of the protective part 123G shown in the above embodiment is merely an example that is preferred from the viewpoint of convenience in the manufacturing process, and the present invention is not limited thereto. . For example, there may be only one protective part, and the opening part may not be provided. Or there may be a structure without a protection part. The open portion 123H may be any one that is exposed to the extent that the surface of the coupling lens 122 to be positioned on the light emitting element side can be gripped by the chuck 300, and does not necessarily exceed the coupling lens 122. It does not have to extend to the side.

  Even when a plurality of protection parts 123G are provided, it is not necessary that the plurality of protection parts 123G have the same shape. Further, the shape of the coupling lens 122 viewed in the optical axis direction may be, for example, an L shape extending from a rectangular holder corner, or a substantially arc shape, instead of a substantially U shape. Well, you may combine them suitably as needed.

  The holder 123 is preferably an integrally molded resin part including the fixing surface 123E and the protective part 123G, but the present invention is not limited thereto. For example, in the configuration in which the protection portion 123G is provided, it is preferable that an external force that may be applied to the protection portion 123G is not transmitted to the coupling lens 122 or the bonding portion thereof, and the protection portion 123G is separated from the holder 123. It may be formed by a member and fixed.

  In the embodiment, the polygon mirror 130 that deflects the laser light by rotating the reflection surface is exemplified as the polarizer of the optical scanning device 100, but the present invention is not limited to this. For example, a oscillating mirror that deflects laser light by oscillating the reflecting surface may be employed.

  In the embodiment, as the imaging optical system of the optical scanning device 100, laser light scanned at a constant angular velocity is converted so as to be scanned at a constant velocity by the fθ lens 150, and then incident on the cylindrical lens 160 by the mirror 170. Although the laser beam focused in the sub-scanning direction by the cylindrical lens 160 is exemplified on the surface to be scanned (photosensitive drum 61) by the mirror 180, the present invention is not limited to this. For example, the fθ lens 150 and the cylindrical lens 160 are used in one set, sharing the function of converting laser light scanned at a constant speed so as to scan at a constant speed and the function of converging the laser light in the sub-scanning direction. It can be replaced with a lens.

  In the embodiment, the example in which the optical scanning device 100 having the light source device 120 is applied to the laser printer 1 has been described. However, the present invention is not limited to this, and other image forming apparatuses such as a copying machine and a multifunction machine are used. It can also be applied to measuring devices other than image forming devices, inspection devices, and the like.

120 Light Source Device 121 Semiconductor Laser (Light Emitting Element)
122 Coupling lens 123 Holder (holding member)
123A Socket part 123B Notch part 123C Opening 123D Fastening part 123E Fixing surface 123F Opening 123G Protection part 123H Opening part

Claims (14)

A light source device comprising: a light emitting element; a coupling lens that collects a light beam emitted from the light emitting element; and a holding member that holds the light emitting element and the coupling lens.
The holding member has a fixed surface facing the surface on the light emitting element side of the coupling lens in the optical axis direction of the coupling lens,
A part of the surface of the coupling lens on the light emitting element side is bonded to the fixed surface.   The light source device according to claim 1, wherein a portion of the coupling lens that is bonded to the holding member is outside a region through which the light beam is transmitted.   The light source device according to claim 1, wherein the coupling lens and the fixing surface are bonded with a photo-curing resin.   The light source device according to claim 3, wherein the photocurable resin is applied to a plurality of positions that are rotationally symmetric when viewed from the optical axis direction of the coupling lens.   The holding member is separated from the coupling lens in a direction perpendicular to the optical axis of the coupling lens, and further downstream of the light beam emission side surface of the coupling lens in the traveling direction of the light beam. The light source device according to claim 1, wherein the light source device has a protruding protective portion. A plurality of the protective portions are provided around the side surface of the coupling lens,
The light source device according to claim 5, wherein the light source device is disposed so as to form an open portion that exposes a side surface of the coupling lens between a pair of adjacent protective portions.   The light source device according to claim 6, wherein a distance between a pair of adjacent protection parts separated by the opening part is larger than a diameter of the coupling lens.   8. The light source device according to claim 6, wherein at least one of the plurality of protection portions is substantially U-shaped when viewed in an optical axis direction of the coupling lens.   9. The light source device according to claim 6, wherein at least one of the plurality of protection portions has a substantially arc shape when viewed in an optical axis direction of the coupling lens.   The light source device according to any one of claims 6 to 9, wherein the opening portion extends to the light emitting element side beyond the coupling lens.   The light source device according to any one of claims 5 to 10, wherein a distance between a side surface of the coupling lens and the protection unit is larger than a radius of the coupling lens.   An end portion of the protection portion extending in the optical axis direction of the coupling lens and being far from the light emitting element is in a plane perpendicular to the optical axis of the coupling lens, and the protection portion is the light emitting device. 12. The light source device according to claim 5, wherein the light source device is a support leg when the holding member is placed on a horizontal surface with an end on an element side facing upward.   The light source device according to claim 1, wherein the holding member is integrally formed. The light source device according to any one of claims 1 to 13,
A deflector for deflecting the light beam emitted from the light source device to scan the surface to be scanned;
An imaging optical system that forms an image on the surface to be scanned with the light beam deflected by the polarizer;
An optical scanning device comprising:

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