JP2021189199A - Optical scanner and image forming apparatus - Google Patents

Abstract

To improve the assemblability of a holding member that holds a light source and a lens.SOLUTION: An optical scanner comprises: a first holding member for holding a light source and a lens; a second holding member for holding the first holding member; and an urging member that urges the first holding member with respect to the second holding member in a direction intersecting with an insertion direction. The first holding member has: a cylindrical part; a light source holding part that is provided at one end of the cylindrical part, is provided projecting in a radial direction from an outer peripheral surface of the cylindrical part, and holds the light source; a lens holding part that is provided at the other end of the cylindrical part, is provided projecting in the radial direction from the outer peripheral surface of the cylindrical part, and holds the lens; a guide rib that is provided projecting in the radial direction on the outer peripheral surface of the cylindrical part, and has a first contact surface that is in contact with the urging member continued on the outer peripheral surface of the lens holding part without steps, and is provided along the insertion direction from the outer peripheral surface of the lens holding part toward the light source; and urging ribs that are provided in the radial direction on the outer peripheral surface of the cylindrical part and provided with second contact surfaces in contact with the urging member in a circumferential direction of the cylindrical part from the first contact surface.SELECTED DRAWING: Figure 6

Description

The present invention relates to an optical scanning apparatus that deflects and scans light from a light source onto an object to be scanned by a deflector, and an image forming apparatus including the optical scanning apparatus.

Conventionally, an optical scanning device used in an electrophotographic image forming apparatus such as a printer or a copying machine periodically deflects and scans light emitted from a light source in response to an image signal by a deflector such as a rotating multi-sided mirror. , The imaging optical system focuses the photosensitive drum as the object to be scanned in a spot shape. The spot light focused on the photosensitive drum forms an electrostatic latent image by the main scan by the deflector and the sub-scan by the rotation of the photosensitive drum, and the image is recorded.

Inside the optical scanning device, a semiconductor laser is provided as the light source, and a rotating polymorphic mirror is provided as the deflector. By rotating this rotating multi-sided mirror at high speed, the laser light emitted from the semiconductor laser is deflected and scanned, and the semiconductor laser is repeatedly emitted and turned off to obtain a desired latent image on the photosensitive drum as the object to be scanned. To form.

In recent years, in image forming apparatus, products that draw high-definition images such as 1200 dpi and 2400 dpi have become mainstream, and products with high output number per unit time and high productivity have been demanded.

As a technique for responding to this, a method of increasing the number of light emitting points of the light source and a method of increasing the rotation speed of the deflector can be considered. In the method of increasing the rotation speed of the deflector, energy consumption is high, so that the lens or mirror vibrates due to the vibration generated during rotation or is deformed due to the temperature rise. In the method of increasing the light emitting points of the light source, the above-mentioned problems can be suppressed, but it is necessary to adjust the light interval in the object to be scanned so as to have a desired value.

Japanese Unexamined Patent Publication No. 11-72729

Patent Document 1 proposes a configuration in which a laser unit including a light source and a lens through which light from the light source passes is rotated around an optical axis to adjust the interval to a desired light. .. The laser unit described in Patent Document 1 includes the light source, the lens, a lens holding member that holds the lens, and a laser holder that holds the light source, the lens, and the lens holding member. Become.

Further, in order to reduce the cost, a configuration is used in which the laser unit is held by the laser holder for the light source and the lens. In this configuration, while each component is miniaturized, the optical magnification from the light source to the surface to be scanned is reduced, and the influence of variations such as temperature rise (thermal deformation of the optical component, etc.) is reduced. The focal length is set long. In this case, since the distance between the light source and the lens is determined by the focal length of the lens, the distance between the light source and the lens becomes long even though the outer diameters of the light source and the lens are about the same.

On the other hand, when molding the laser holder, it is necessary to prevent the laser holder from being damaged or deformed in the process of pulling out the laser holder from the mold in the direction from the lens side to the light source side. Therefore, the cylindrical portion of the laser holder from the portion that holds the light source to the portion that holds the lens is tilted so that the outer diameter on the lens side is smaller than the outer diameter on the light source side. By tilting the cylindrical part of the laser holder, it becomes easier to pull out the laser holder from the mold. Therefore, the cylindrical portion of the laser holder has a constricted shape that is thinner than the portion that holds the light source and the portion that holds the lens. However, if the cylindrical portion of the laser holder is tilted with respect to the outer diameter on the lens side as described above, the outer diameter on the light source side becomes large and the laser holder becomes large. Therefore, the central portion between the portion that holds the light source and the portion that holds the lens of the laser holder has a so-called constriction shape in which the outer diameter is smaller than that of the portion that holds the light source and the portion that holds the lens.

However, when the laser holder is constricted, a step is generated between the portion of the laser holder that holds the lens and the central portion. Therefore, when assembling the laser holder, the step is caught and the assembling property of the laser holder is deteriorated.

Therefore, an object of the present invention is to improve the assembleability of a laser holder holding a light source and a lens.

In order to achieve the above object, the present invention is an optical scanning device that deflects and scans light from a light source onto an object to be scanned by a deflector, wherein the light source, a lens through which light from the light source passes, and the light source. A first holding member for holding the lens, a second holding member for holding the first holding member, and the second holding member provided on the second holding member. On the other hand, when the first holding member is inserted in the insertion direction from the light source side toward the lens side, it comes into contact with the first holding member and the first holding member is brought into contact with the second holding member. The first holding member includes a urging member for urging in a direction intersecting the insertion direction, and the first holding member includes a cylindrical cylindrical portion through which light emitted from the light source passes through and a cylindrical portion of the cylindrical portion. A light source holding portion that is provided at one end of the cylindrical portion in the longitudinal direction and projects radially from the outer peripheral surface of the cylindrical portion to hold the light source, and the other of the cylindrical portion in the longitudinal direction. A lens holding portion for holding the lens, which is provided at the end portion and protrudes radially from the outer peripheral surface of the cylindrical portion, and a urging member which protrudes radially from the outer peripheral surface of the cylindrical portion. The first contact surface to be abutted is continuous with the outer peripheral surface of the lens holding portion without a step, and the guide rib provided along the insertion direction from the outer peripheral surface of the lens holding portion toward the light source side and the outer periphery of the cylindrical portion. A second contact surface that is radially projected from the surface and with which the urging member abuts has an urging rib provided in the circumferential direction of the cylindrical portion from the first contact surface. It is a feature.

According to the present invention, when the first holding member holding the light source and the lens is inserted into the second holding member, the urging member abuts on the guide rib provided on the first holding member and guides in the insertion direction. Will be done. As a result, the urging member does not get caught in the step between the lens holding portion and the cylindrical portion of the first holding member, and the assembleability of the first holding member that holds the light source and the lens can be improved.

Schematic cross-sectional view showing a schematic configuration of an image forming apparatus provided with an optical scanning apparatus. The figure which shows the incident optical system in an optical scanning apparatus. The figure which shows the emission optical system in an optical scanning apparatus. The figure which shows the light source unit in an optical scanning apparatus. The figure where the tip holder is attached to the laser holder The figure where the tip holder is attached to the laser holder (A) A diagram showing how the laser beam is scanned on the photosensitive drum in the main scanning direction, (b) an enlarged view of scanning lines on the photosensitive drum, and (c) a semiconductor laser having a plurality of light emitting points are shown. figure Cross section of the tip holder The figure which shows the opening amount of the urging member in an optical scanning apparatus. The figure which shows the process of attaching a chip holder to a laser holder

Hereinafter, preferred embodiments of the present invention will be exemplified in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described in the following embodiments should be appropriately changed depending on the configuration of the apparatus to which the present invention is applied and various conditions. It is not intended to limit the scope of the invention to those alone.

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

The intermediate transfer belt 20 is formed in an endless shape and is hung around a pair of belt transport rollers 21 and 22, and a toner image formed by each image formation engine 10 is transferred while rotating in the direction of arrow H. It is configured as follows. Further, a secondary transfer roller 23, which is a second transfer means, is arranged at a position facing the one belt transfer roller 21 with the intermediate transfer belt 20 interposed therebetween. The recording sheet P is inserted between the secondary transfer roller 23 and the intermediate transfer belt 20 which are in pressure contact with each other, and the toner image is transferred from the intermediate transfer belt 20. The four image-forming engines 10Y, 10M, 10C, and 10Bk described above are arranged in parallel on the lower side of the intermediate transfer belt 20, and a toner image formed according to the image information of each color is formed on the intermediate transfer belt. It is designed to be transferred to 20 (hereinafter referred to as primary transfer). These four image-forming engines 10 include an image-forming engine 10Y for yellow, an image-forming engine 10M for magenta, and an image-forming engine 10C for cyan along the rotation direction (arrow H direction) of the intermediate transfer belt 20. And the image formation engine for black 10Bk are arranged in this order.

Further, below the image forming engine 10, an optical scanning device 40 for exposing a photosensitive drum (photoreceptor) 11 which is an object to be scanned provided in each image forming engine 10 according to image information is arranged. .. The optical scanning device 40 is shared by all image forming engines 10Y, 10M, 10C, and 10Bk, and is a light source that emits a laser beam (light beam) that is light modulated according to the image information of each color 4. It comprises a base semiconductor laser 62 (see FIG. 2). Further, the optical scanning device 40 includes a rotating multi-sided mirror unit (hereinafter referred to as a deflector) 41 that rotates at high speed and deflects and scans the laser beam of these four optical paths along the rotation axis direction of each photosensitive drum 11. Each laser beam scanned by the deflector 41 travels on a predetermined path while being guided by an optical member installed in the optical scanning device 40. Then, each laser beam that has traveled along the predetermined path exposes each photosensitive drum 11 of each image formation engine 10 through the dustproof glass 42, which is each irradiation port provided in the upper part of the optical scanning device 40.

Further, each image formation engine 10 includes a photosensitive drum 11 and a charging roller 12 that charges the photosensitive drum 11 to a uniform background potential. Further, each image forming engine 10 includes a developer 13 which is a developing means for developing an electrostatic latent image formed on the photosensitive drum 11 (on the object to be scanned) by exposure to a laser beam to form a toner image. ing. The developer 13 forms a toner image corresponding to the image information of each color on the photosensitive drum 11 which is a photoconductor. The developer 13 is a method using a two-component developer in which toner and carriers are mixed. The developer 13 is replenished with a developer in which toner and a carrier are mixed from a replenishment cartridge (not shown) in order to omit maintenance for replacement of the developer due to changes over time. For the developer 13, a developing method is used in which the deteriorated developer is automatically discharged. As described above, each image forming engine 10 includes a photosensitive drum 11 as an object to be scanned, a charging roller 12 (charging means), and a developer 13 (developing means) as process means acting on the photosensitive drum 11.

At a position facing the photosensitive drum 11 of each image forming engine 10, a primary transfer roller 15 as a first transfer means is arranged so as to sandwich an intermediate transfer belt 20. When a predetermined transfer voltage is applied to the primary transfer roller 15, the toner image on the photosensitive drum 11 is transferred to the intermediate transfer belt 20.

On the other hand, the recording sheet P is supplied from the paper feed cassette 2 housed in the lower part of the printer housing 1 to the inside of the printer, specifically, the secondary transfer position where the intermediate transfer belt 20 and the secondary transfer roller 23 abut. Will be done. A pickup roller 24 and a paper feed roller 25 for pulling out the recording sheet P housed in the paper feed cassette 2 are arranged side by side on the upper part of the paper feed cassette 2. Further, a retard roller 26 for preventing double feeding of the recording sheet P is arranged at a position facing the paper feed roller 25. The transport path 27 of the recording sheet P inside the printer is provided substantially vertically along the right side surface of the printer housing 1. The recording sheet P pulled out from the paper feed cassette 2 located at the bottom of the printer housing 1 is sent to the registration roller 29 through the transport path 27. Further, the recording sheet P is fed with the entry timing controlled with respect to the secondary transfer position by the registration roller 29. After that, the recording sheet P is transferred to the fixing device 3 which is a fixing means provided on the downstream side in the transport direction after the toner image is transferred at the secondary transfer position. The unfixed toner image on the recording sheet P (on the recording medium) is fixed on the recording sheet P by the fixing device 3. Then, the recording sheet P on which the toner image is fixed by the fixing device 3 is discharged to the discharge tray 1a provided on the upper part of the printer housing 1 via the discharge roller 28.

In forming a full-color image by the color laser beam printer configured as described above, first, the optical scanning apparatus 40 exposes the photosensitive drum 11 of each image formation engine 10 at a predetermined timing according to the image information of each color. As a result, a latent image corresponding to the image information is formed on the photosensitive drum 11 of each image forming engine 10. Here, in order to obtain high-quality image quality, the latent image image formed by the optical scanning device 40 must be accurately reproduced at a predetermined position on the photosensitive drum 11.

[Configuration of optical scanning device]
FIG. 2 is a schematic diagram showing a schematic diagram of a light beam emitted from a light source reaching the deflector 41, and FIG. 3 is a schematic diagram showing an optical path of the light beam deflected by the deflector 41 leading to each photosensitive drum 11. ..

Inside the optical scanning device 40, a semiconductor laser 62, a collimator lens 63, a chip holder 61, a laser holder 68, a deflector 41, a cylindrical lens 46, optical lenses 43a, 43b, reflection mirrors 44a to 44d, and the like are housed 49. It is installed inside. Here, a configuration in which four chip holders 61 are provided is illustrated, and the light from the light source of each chip holder is guided to the corresponding photosensitive drum 11.

The chip holder 61 is a first holding member for holding the semiconductor laser 62 which is a light source and the collimator lens 63 through which the light from the semiconductor laser 62 passes. Further, the chip holder 61 is provided with a sub-scanning diaphragm 64. The diffused light emitted from the semiconductor laser 62 is converted into parallel light by the collimator lens 63 and emitted. The light beam emitted from the semiconductor laser 62 of the chip holder 61 has a desired light beam width defined by the main scanning diaphragm 47, and is focused on the deflector 41 by the cylindrical lens 46. In FIG. 2, the optical axis of the tip holder 61 is arranged so as to have an angle with respect to a plane orthogonal to the rotation axis of the deflector 41. The light beam deflected by the deflector 41 passes through the optical lenses 43a, 43b, is reflected by the reflection mirrors 44a, 44b, 44c, 44d, passes through the dustproof glass 42 provided on the lid 48, and is scanned by the object to be scanned. An image is formed on a certain photosensitive drum 11. A light-shielding wall 50 is provided between the deflector 41 and the optical lens 43a closest to the deflector 41.

Further, the tip holder 61 will be described. FIG. 4 is a detailed view of the chip holder 61 holding the semiconductor laser 62 and the collimator lens 63. The chip holder 61, which is the first holding member, includes a cylindrical portion 65c, a light source holding portion 65a for holding the semiconductor laser 62, a lens holding portion 65b for holding the collimator lens 63, a guide rib 66, and an urging rib 67. ,have. The cylindrical portion 65c has a cylindrical shape with a hollow inside so that the light emitted from the semiconductor laser 62 can pass through the inside.

The light source holding portion 65a is provided at one end of the cylindrical portion 65c in the first direction, and projects radially from the outer peripheral surface of the cylindrical portion 65c. The lens holding portion 65b is provided at the other end of the cylindrical portion 65c in the first direction, and projects radially from the outer peripheral surface of the cylindrical portion 65c. The semiconductor laser 62 is press-fitted and held by the light source holding portion 65a of the chip holder 61, and the collimator lens 63 is adhered and held by the lens holding portion 65b. The tip holder 61 is provided with a guide rib 66 extending in the first direction on the outer peripheral surface of the cylindrical portion 65c between the light source holding portion 65a and the lens holding portion 65b, and the second is orthogonal to the first direction. An urging rib 67 is provided so as to extend in the direction. Here, the first direction is the insertion direction in which the chip holder 61 holding the semiconductor laser 62 and the collimator lens 63 is inserted into the laser holder 68 (see FIG. 5), and the chip holder 61 is from the light source side to the lens side. (The direction of the arrow in the figure). That is, the first direction is the same as the longitudinal direction of the cylindrical portion 65c. The second direction is a direction orthogonal to the insertion direction, and is a circumferential direction of the cylindrical portion 65c of the tip holder 61.

The guide rib 66 is radially projected from the outer peripheral surface of the cylindrical portion 65c. The guide rib 66 has a first contact surface 66a with which the urging member 69 (see FIG. 6), which will be described later, abuts in the insertion direction (first) from the outer peripheral surface of the lens holding portion 65b toward the semiconductor laser side which is the light source side. It is provided along the direction). The urging rib 67 is radially projected on the outer peripheral surface of the cylindrical portion 65c. The urging rib 67 is provided with a second contact surface 67a with which the urging member 69 abuts in the circumferential direction (second direction) of the cylindrical portion 65c from the first contact surface 66a. In the guide rib 66, the first contact surface 66a is connected to the outer peripheral surface of the lens holding portion 65b without a step. However, the guide rib 66 is allowed as long as the step of the first contact surface 66a with the outer peripheral surface of the lens holding portion 65b is within the tolerance range of 0.1 mm. Further, the urging rib 67 is connected in a direction in which the second contact surface 67a intersects the first contact surface 66a without a step. Further, the urging rib 67 is provided between the semiconductor laser 62 and the collimator lens 63 in the insertion direction (first direction).

As shown in FIGS. 5 and 6, the optical scanning device 40 includes a laser holder 68 which is a second holding member for holding the chip holder 61 which is the first holding member. Further, the optical scanning device 40 includes an urging member 69 that abuts on the chip holder 61 and urges the chip holder 61 with respect to the laser holder 68 in a direction intersecting the insertion direction. The urging member 69 is provided on the laser holder 68. FIG. 5 is a diagram in which a chip holder 61 holding a semiconductor laser 62 and a collimator lens 63 is attached to the laser holder 68. FIG. 6 is a view showing the tip holder 61 and the urging member 69 by seeing through the laser holder 68 (not shown) in FIG.

Here, the assembly procedure will be described. The semiconductor laser 62 is press-fitted into the light source holding portion 65a of the chip holder 65 and held in the chip holder 61. The collimator lens 63 is adhered to the lens holding portion 65b of the chip holder 65 and held by the chip holder 61. The chip holder 61 holding the semiconductor laser 62 and the collimator lens 63 is inserted into the laser holder 68 in the insertion direction in which the chip holder 61 is directed from the semiconductor laser 62 side to the collimator lens 63 side. Here, the insertion direction of the tip holder 61 with respect to the laser holder 68 is the same as the above-mentioned first direction (the direction of the arrow in FIG. 4). The urging member 69 comes into contact with the tip holder 61 when the tip holder 61 is inserted into the laser holder 68 in the insertion direction. The urging member 69 in contact with the tip holder 61 urges the tip holder 61 with respect to the laser holder 68 in a direction intersecting the insertion direction as described above. That is, the tip holder 61 is urged to the laser holder 68 by the urging member 69. After being inserted into the laser holder 68, the chip holder 61 is rotated in the direction of the arrow f, irradiated from the semiconductor laser 62, and the scanning line spacing of the light scanned on the photosensitive drum is adjusted. After that, the chip holder 65 is adhered to the adhesive portion 70 of the laser holder 68 with an adhesive and fixed to the laser holder 68.

Here, the adjustment of the scanning line spacing will be described with reference to FIG. 7A. The chip holder 61 measures the scanning line spacing on the object to be scanned (on the photosensitive drum), and is adhesively fixed to the laser holder 68 at the adhesive portion 70 at an angle of a desired value.

FIG. 7A is a diagram showing a state in which the laser beam emitted from the semiconductor laser 62 and reflected by the reflecting surface of the deflector 41 is scanned on the photosensitive drum 11 in the main scanning direction. FIG. 7B is an enlarged view of a scanning line on the photosensitive drum 11 shown in FIG. 7A. FIG. 7C is a diagram showing a semiconductor laser 62 having four light emitting points LD1, LD2, LD3, and LD4 as a plurality of light emitting points. In FIG. 7B, SLD1 shows a spot formed on the photosensitive drum 11 by the laser beam emitted from the emission point LD1 of the semiconductor laser 62. The SLD 2 indicates a spot formed on the photosensitive drum 11 by the laser beam emitted from the light emitting point LD2 of the semiconductor laser 62. The SLD 3 indicates a spot formed on the photosensitive drum 11 by the laser beam emitted from the light emitting point LD3 of the semiconductor laser 62. The SLD 4 indicates a spot formed on the photosensitive drum 11 by the laser beam emitted from the light emitting point LD4 of the semiconductor laser 62.

As shown in FIG. 7B, the distance between the spots of the laser beam on the photosensitive drum 11 is defined as ΔD (hereinafter referred to as the spot distance). The semiconductor laser 62 is adjusted by rotating the chip holder 61 in the arrow f direction when assembling the optical scanning device at the factory so that the spot spacing ΔD corresponds to the resolution of the image forming apparatus. At this time, the tip holder 61 is rotated in the direction of the arrow f by operating the knob 61a. The knob 61a is provided on the light source holding portion 65a side on the upstream side in the insertion direction of the tip holder 61, and is extended in the second direction so that the rotation can be easily adjusted. The knob 61a is operated to adjust the rotation of the chip holder 61 holding the semiconductor laser 62. As a result, the positional relationship (exposure position relationship) of the spots on the photosensitive drum 11 of the laser light emitted from each light emitting point LD1, LD2, LD3, LD4 in the semiconductor laser 62 is as shown in FIG. 7 (b). Assuming that the distance between the spot SLD1 and the spot SLD4 is F, the spot distance ΔD is expressed as ΔD = F / 3.

[Shape of tip holder]
The diameter of the semiconductor laser 62 and the collimator lens 63 has been reduced due to the demand for miniaturization and cost reduction. FIG. 8 is a cross-sectional view of the tip holder 61. As shown in FIG. 8, in this embodiment, the outer diameter d1 of the semiconductor laser 62 is φ5.6 mm, and the outer diameter d2 of the collimator lens 63 is φ8 mm. The focal length of the collimator lens 63 is 37 mm, which is substantially equal to the distance between the light emitting point of the semiconductor laser 62 and the collimator lens 63. The focal length of the collimator lens 63 should be set as appropriate, and is not limited thereto. In an optical scanning device having a light source having a plurality of light emitting points, it is desired to extend the focal length of the collimator lens 63 in order to reduce the optical magnification from the light emitting point to the surface to be scanned and to reduce the influence of variation such as temperature rise. There is a request.

Since the chip holder 61 is inserted into the laser holder 68, the collimator lens 63 side, which is the downstream side in the insertion direction (tip side in the insertion direction), is thinner than the semiconductor laser 62 side, which is the upstream side in the insertion direction. Must be in the shape of the lens.

Further, since the tip holder 61 is manufactured by resin molding, it is necessary to equalize the wall thickness t in order to stabilize the molding accuracy. A wall thickness t of 2 mm is required to have sufficient rigidity. In order to remove the chip holder 61 from the mold by the eject pin, the chip holder 61 is arranged in the molding mold so that the semiconductor laser 62 side on which the pin can be arranged is the core side (movable side). In order to improve the releasability, the cylindrical surface inside the chip holder 61 is provided with a draft so as to become thinner from the semiconductor laser 62 side toward the collimator lens 63 side. Generally, the draft angle is about 1 deg.

Here, since the focal length of the collimator lens 63 is 37 mm as described above, the draft of 1 deg is the diameter on the tip side in the insertion direction from the following equation (37 × tan (1 deg) × 2 ≈ 1.3). Is reduced by about 1.3 mm. Since the diameter of the semiconductor laser 62 is 5.8 mm, the inner diameter d3 of the tip of the cylindrical portion 65c in the chip holder 65 is about 4.3 mm. On the other hand, since the outer diameter of the collimator lens 63 is φ8 mm, a step is inevitably generated between the lens holding portion 65b and the cylindrical portion 65c on the tip end side of the tip holder 65. As described above, the guide rib 66 is provided on the cylindrical portion 65c of the tip holder 61 so that the urging member 69 can pass through the tip holder 61 without being caught in the step when the tip holder 61 is assembled.

Here, FIG. 9A shows the shape of the urging member 69 before inserting the tip holder 61 into the laser holder 68. Further, FIG. 9B shows the shape of the urging member 69 after the tip holder 61 is inserted into the laser holder 68. Since the urging member 69 generates an urging force after the tip holder 61 is inserted, the tip holder shown in FIG. 9D is compared with the opening amount α before the tip holder 61 is inserted shown in FIG. 9A. It is necessary that the opening amount β after the insertion of 61 is small.

If the opening amount of the urging member 69 before the insertion of the tip holder 61 is increased, the urging member 69 comes into contact with the collimator lens 63 at the time of insertion. It is necessary to set the opening amount α. Therefore, in order to reduce the opening amount β after insertion, an urging rib 67 is provided on the outer peripheral surface of the cylindrical portion 65c of the tip holder 61 so as to project radially.

[Assembly of tip holder]
10 (a) to 10 (d) are views showing a process of attaching the chip holder 61 to the laser holder 68. Although the laser holder 68 is not shown for simplification, the chip holder 61 is urged to the receiving portion 68a provided in the vertical direction of the laser holder 68 shown in FIG. Here, a configuration in which two chip holders 61 are attached to one laser holder 68 is illustrated.

FIG. 10A shows a state before the two chip holders 61 are inserted into the laser holder. At this time, the urging member 69 is opened with the opening amount α shown in FIG. 9A. Specifically, the opening of the urging member 69 is about the same height as the insertion direction tip portion (lens holding portion 65b) of the tip holder 65 that adheres and holds the collimator lens 63. This prevents the urging member 69 from coming into contact with the collimator lens 63 of the tip holder 61 inserted into the laser holder. Further, the guide rib 66 of the tip holder 61 has its first contact surface 66a connected to the outer peripheral surface of the lens holding portion 65b without a step. That is, the guide rib 66 of the tip holder 61 is provided at the same position as the outer peripheral surface of the lens holding portion 65b in the circumferential direction of the tip holder 61. This makes it possible to insert the urging member 69 in a phase that does not contact the collimator lens 63 when the tip holder 61 is inserted.

FIG. 10B is a diagram when one tip holder 61 is inserted into the laser holder and the urging member 69 is transferred from the lens holding portion 65b of the tip holder 61 to the guide rib 66. When the tip holder 61 is inserted into the laser holder, the lens holding portion 65b, which is the tip of the tip holder 61, comes into contact with the urging member 69 and pushes the urging member 69 in a direction in which the opening amount becomes smaller. At this time, the outer peripheral surface of the lens holding portion 65b and the first contact surface 66a of the guide rib 66 are arranged in the same phase in the circumferential direction of the tip holder 61, and are arranged between the lens holding portion 65b and the cylindrical portion 65c. It is arranged so that there is no step. Therefore, the urging member 69 is guided from the outer peripheral surface of the lens holding portion 65b provided on the tip holder 61 to the first contact surface 66a of the guide rib 66 without being caught by the step.

FIG. 10 (c) is a diagram when one tip holder 61 is further inserted and passed from the first contact surface 66a of the guide rib 66 to the second contact surface 67a of the urging rib 67. The second contact surface 67a of the urging rib 67 is connected to the first contact surface 66a of the guide rib 66 in a direction in which there is no step and intersects with the first contact surface 66a. Therefore, there is no step between the first contact surface 66a of the guide rib 66 and the second contact surface 67a of the urging rib 67, and the urging member 69 is inserted from the guide rib 66 into the urging rib 67. Delivery is smooth.

FIG. 10D is a diagram in which one of the tip holders 61 is further inserted and is in an attached state. The urging rib 67 is a rib extending in the circumferential direction of the tip holder 61, and its second contact surface 67a is continuous with the first contact surface 66a of the guide rib 66 in a direction in which there is no step and intersects. Therefore, there is no step between the first contact surface 66a of the guide rib 66 and the second contact surface 67a of the urging rib 67, and the insertion direction of the urging member 69 from the guide rib 66 to the urging rib 67. Delivery in the direction of intersection is also smooth. As a result, even when the tip holder 61 is rotated around the optical axis for rotation adjustment, the urging force applied to the tip holder 61 by the urging member 69 does not change, and the position is stable.

After that, the assembly of the light source unit is completed by inserting the other chip holder into the laser holder in the same manner as the one chip holder.

As described above, according to the present embodiment, when the tip holder 61 is inserted into the laser holder 68, the urging member 69 abuts on the guide rib 66 provided in the tip holder 61 and is guided in the insertion direction. As a result, the urging member 69 does not get caught in the step between the lens holding portion 65b and the cylindrical portion 65c of the tip holder 61, and the assembling property of the tip holder 61 can be improved.

Further, the urging rib 67 is connected in a direction in which the second contact surface 67a intersects the first contact surface 66a of the guide rib 66 without a step. As a result, even when the tip holder 61 is rotated in the circumferential direction (around the optical axis), the tip holder 61 is stably urged by the urging member 69, so that the assembling property is good.

Further, even when the tip holder 61 is pulled out, the urging member 69 moves on the first contact surface 66a of the guide rib 66, so that the insertability is good.

Further, when the tip holder 61 is inserted, the urging member 69 does not come into contact with the collimator lens 63, and it is possible to prevent the occurrence of scratches and the displacement of the lens position.

Further, the urging rib 67 is provided between the semiconductor laser 62 and the collimator lens 63 in the insertion direction. As a result, the tip holder 61 is urged by the urging member 69 between the semiconductor laser 62 and the collimator lens 63, so that the angle of the optical axis is accurately maintained.

Further, since there is no step at the boundary between the urging rib 67 and the guide rib 66, the assembleability is good.

In the above-described embodiment, four image-creating engines are used, but the number of engines used is not limited and may be appropriately set as needed.

Further, in the above-described embodiment, the printer is exemplified as the image forming apparatus, but the present invention is not limited thereto. For example, it may be another image forming apparatus such as a copying machine or a facsimile apparatus, or another image forming apparatus such as a multifunction device combining these functions. Alternatively, it may be an image forming apparatus that uses a recording medium carrier and sequentially superimposes and transfers toner images of each color on the recording medium supported on the recording medium carrier. Similar effects can be obtained by applying the present invention to the optical scanning apparatus used in these image forming apparatus.

11 ... Photosensitive drum 40 ... Optical scanning device 41 ... Deflection 61 ... Chip holder 62 ... Semiconductor laser 63 ... Collimator lens 65a ... Light source holding part 65b ... Lens holding part 65c ... Cylindrical part 66 ... Guide rib 66a ... First contact surface 67 ... Biasing rib 67a ... Second contact surface 68 ... Laser holder 69 ... Biasing member

Claims (5)

An optical scanning device that deflects and scans the light from a light source onto an object to be scanned by a deflector.
With the light source
A lens through which light from the light source passes and
A first holding member for holding the light source and the lens, and
A second holding member for holding the first holding member, and
It is provided on the second holding member, and when the first holding member is inserted into the second holding member in the insertion direction from the light source side toward the lens side, it comes into contact with the first holding member. A urging member that urges the first holding member in a direction intersecting the insertion direction with respect to the second holding member.
Equipped with
The first holding member is
A cylindrical portion having a cylindrical shape through which light emitted from the light source passes through,
A light source holding portion for holding the light source, which is provided at one end of the cylindrical portion in the longitudinal direction of the cylindrical portion and projects radially from the outer peripheral surface of the cylindrical portion.
A lens holding portion for holding the lens, which is provided at the other end of the cylindrical portion in the longitudinal direction and projects radially from the outer peripheral surface of the cylindrical portion.
The first contact surface that is radially projected from the outer peripheral surface of the cylindrical portion and with which the urging member abuts is continuously connected to the outer peripheral surface of the lens holding portion without a step, and is from the outer peripheral surface of the lens holding portion to the light source side. With the guide ribs provided along the insertion direction,
A second contact surface that is radially projected from the outer peripheral surface of the cylindrical portion and with which the urging member abuts is provided with an urging rib provided in the circumferential direction of the cylindrical portion from the first contact surface. ,
An optical scanning device characterized by having. The optical scanning apparatus according to claim 1, wherein the urging rib is continuous with the first contact surface in a direction in which the second contact surface has no step and intersects with the first contact surface. The optical scanning apparatus according to claim 1 or 2, wherein the urging rib is provided between the light source and the lens in the insertion direction. The first holding member according to any one of claims 1 to 3, wherein the first holding member is provided with a gradient so that the cylindrical surface inside the cylindrical portion becomes thinner from the light source side toward the lens side. Optical scanning device. An image forming apparatus comprising a photoconductor and an optical scanning device according to any one of claims 1 to 4, which exposes the photoconductor according to image information.

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