JP2014139627A - Light source unit, scanning optical device, and image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source unit that absorbs deformation caused by heat from the outside to eliminate influences on the fitting positions of components, and to provide a scanning optical device and an image formation device that include the light source unit.SOLUTION: As shown in FIG. 7, a light source unit 500 comprises open holes (light-emitting element installation units) 565y, 565m, 565c, 565k that are provided on a light source holding unit 562a, aligned in order from a side closer to an optical scanning unit 84. The open holes 565y, 565m, 565c, 565k are provided such that their hights are in order of 565y, 565m, 565c and 565k when the open hole 565y closest to the optical scanning unit 84 serving as a heat source is located at the lowest position and the open hole 565k furthest from the optical scanning unit 84 is located at the highest position.

Description

  The present invention relates to a light source unit that emits laser light to perform exposure scanning to form an electrostatic latent image on a photoconductor, a scanning optical device, and an image forming apparatus including the scanning optical device. The present invention relates to a light source unit for irradiating a beam, a scanning optical device, and an image forming apparatus including the scanning optical device.

  2. Description of the Related Art An electrophotographic image forming apparatus includes a scanning optical device that irradiates a surface of a photosensitive drum with a light beam using a laser beam so that a toner image to be transferred onto a recording sheet is carried on the photosensitive drum. The scanning optical device irradiates and scans the surface of the photosensitive drum with a light beam to form an electrostatic latent image on the surface of the photosensitive drum, and the electrostatic latent image is visualized with toner. Thus, a toner image is formed. In such an electrophotographic image forming apparatus that prints out a color image on a recording sheet, a light beam is applied to a plurality of photosensitive drums that carry toner images of respective colors. What has a scanning optical device capable of being provided is provided.

  As a scanning optical device in the image forming apparatus, there is disclosed an optical scanning unit that can easily adjust the optical axis of each light beam by fine adjustment of a single light source unit corresponding to each color (see Patent Document 1). In this optical scanning unit of Patent Document 1, each color single light source unit is configured by attaching a substrate on which a light source is mounted to a bracket of a metal member, and the bracket is brought into contact with the same plane of a metal mounting base. It is supposed to be attached. Thereby, the optical axis of the light beam radiate | emitted from each single light source unit can be adjusted with high precision by adjusting the position of the single light source unit to which the attachment base material is attached in the surface direction.

Japanese Patent No. 4231011

  In an electrophotographic image forming apparatus, the positional relationship between a laser diode, which is a light source, and a collimator lens greatly affects the adjustment of light beam focus and registration. Therefore, in the light source unit to which the laser diode and the collimator lens are attached, a configuration is required in which the positional relationship between the laser diode and the collimator lens can be adjusted with high accuracy and the adjusted positional relationship can be maintained from the initial state. Therefore, a metal material such as aluminum having high rigidity has been used as a material constituting the light source unit as in the optical scanning unit of Patent Document 1.

  However, since a metal material is often formed by die casting, it is difficult to process a light source unit that requires high accuracy. Therefore, the light source unit made of a metal material, like the optical scanning unit of Patent Document 1, requires secondary processing for adjusting the position of the single light source unit attached to the attachment member, and is expensive. It was. On the other hand, when the secondary processing is omitted, in the assembly work of the light source unit, the installation work of the single light source unit for adjusting the optical axis of the light beam becomes complicated.

  The light source unit can also be configured using a resin material that is easier to process than a metal material. However, since the resin material is not only weak in the light source unit but also greatly affected by heat, it is made of resin material by the heat generated when the deflector (polygon mirror) that scans the light beam is rotated. The light source unit is deformed. Therefore, the positional relationship between the laser diode adjusted at the time of attachment and the collimator lens is shifted, resulting in a shift in the focus and registration of the light beam, leading to image quality degradation.

  An object of the present invention is to provide a light source unit that does not affect the mounting position of each component by absorbing deformation caused by heat from the outside, and a scanning optical device and an image forming apparatus including the light source unit. And

  The light source unit of the present invention includes a plurality of light emitting elements that emit light beams, an optical member that guides a plurality of light beams emitted from each of the plurality of light emitting elements to irradiate an external optical scanning unit, A light source holding part for holding a light source unit; and an optical system holding part for holding the optical member, and the optical system holding part is fixed to a scanning optical device having the light scanning part for deflecting and scanning a light beam. The light source holding unit includes a surface that is erected from a side portion of the optical system holding unit and that is perpendicular to the optical axis of the light beam emitted from the light emitting element. The plurality of light emitting elements held by the light source holding unit are fixed side by side in a direction parallel to the surface of the optical system holding unit, and at a height position along a direction away from the optical scanning unit Is high Characterized in that it is arranged so that.

  In such a light source unit, the light source holding unit includes a light emitting element installation unit in which the light emitting element is installed, and a light emitting element fixing unit that fixes the light emitting element installed in the light emitting element installation unit, When the direction in which a plurality of light emitting elements are arranged is the left and right direction, the light emitting element fixing portions may be disposed on both the left and right sides of the light emitting element installation portion. The light emitting element fixing portion may be disposed above and below the light emitting element installation portion.

  In each of the light source units described above, the light source holding part is at least one of the positions between the fixed light emitting elements from the end opposite to the connecting part to the optical system holding part to the lower side. It does not matter as a thing provided with the notch used as a notch.

  In these light source units, the optical member includes a plurality of collimator lenses in which a light incident surface is disposed at a position facing the irradiation surface of each of the plurality of light emitting elements.

  In any of the light source units described above, the light source holding part and the optical system holding part may be integrally formed of a resin material.

  Furthermore, in any one of the light source units described above, a part of the fixed position to the scanning optical device may be in the vicinity of both sides of the connection portion between the light source holding unit and the optical system holding unit.

A scanning optical device of the present invention is a scanning optical device including a light source unit that irradiates a plurality of light beams and an optical scanning unit that deflects and scans each of the plurality of light beams emitted from the light source unit.
Any one of the light source units described above is installed in the light source unit.

  An image forming apparatus according to the present invention includes: the above-described scanning optical device; and a plurality of photosensitive drums that form an electrostatic latent image on a surface by being irradiated with each of a plurality of light beams from the scanning optical device. And

  According to the present invention, the light emitting element disposed near the optical scanning unit serving as the heat source is installed at a position close to the optical system holding unit fixed to the scanning optical device, so that the light emitting element close to the heat source is fixed. The position where the influence of thermal deformation of the light source holding part is small can be set. Therefore, since the positional deviation of the light emitting element can be suppressed, the optical performance set with high accuracy in the initial state can be maintained.

  In addition, by arranging the light emitting element fixing parts on both the left and right sides of the light emitting element installation part, the light emitting element can be installed as close to the optical system holding part as possible, so that the influence of thermal deformation of the light source holding part can be further reduced. . Further, by providing a notch between the light emitting element installation positions, it is possible to reduce the mutual influence of thermal deformation in each of the light emitting element installation areas. Furthermore, by positioning a part of the fixed position to the scanning optical device in the vicinity of both sides of the connection part of the light source holding part and the optical system holding part, the rigidity of the holding member by the light source holding part and the optical system holding part is increased, Thermal deformation of the light source holding part can be suppressed.

1 is a schematic diagram illustrating an internal configuration of an image forming apparatus of the present invention. It is a schematic sectional drawing which shows the internal structure of the scanning optical apparatus of this invention. It is a top view which shows the internal structure of the scanning optical apparatus of FIG. It is an enlarged view which shows the structure of the principal part of the light source part and optical scanning part of the scanning optical apparatus of FIG. It is a top view which shows the structure of the light source unit installed in the light source part shown in FIG. It is a schematic sectional drawing which shows the structure of the light source holding part in the light source unit of FIG. It is a front view which shows the structure of the holding member of the light source unit in the 1st Embodiment of this invention. It is a front view which shows the structure of the light source unit in the 1st Embodiment of this invention. It is a front view which shows the structure of the holding member of the light source unit in the 2nd Embodiment of this invention. It is a front view which shows the structure of the light source unit in the 2nd Embodiment of this invention. It is a front view which shows the structure of the light source unit in the 3rd Embodiment of this invention. It is a front view which shows another structure of the light source unit in the 3rd Embodiment of this invention.

<Overall configuration of image forming apparatus>
An overall configuration of an image forming apparatus common to the following embodiments will be described with reference to the drawings. FIG. 1 is a schematic diagram showing the internal configuration of the image forming apparatus of the present invention.

  As shown in FIG. 1, the image forming apparatus 1 includes an image reading device 3 that reads an image from a document, a paper feeding device 4 that stores recording paper on which an image is formed, and a toner image after the toner image is formed. The image forming unit 5 for transferring the toner image to the recording paper fed from the paper feeding device 4, the fixing device 6 for fixing the toner image transferred to the recording paper by the image forming unit 5, and the image fixed by the fixing device 6 Is provided with a paper discharge tray 7 on which the recording paper on which is formed is discharged, and a scanning optical device 8 that irradiates the photosensitive drum 61 in the image forming unit 5 with laser light. In this image forming apparatus 1, an image reading device 3 is provided on the upper part of the apparatus main body 2, and inside the apparatus main body 2, as shown in FIG. 1, a sheet feeding device 4, a scanning optical device 8, Each of the image forming unit 5 and the fixing device 6 is provided.

  The paper discharge tray 7 is provided on the upper side of the apparatus main body 2 in order to receive the recording paper on which the image is recorded and discharged by the fixing device 6, and the paper supply apparatus 3 is connected to the image forming unit 5 in the apparatus main body 2. It is configured to be insertable / removable on the lower side. With this configuration, the recording paper stored in the paper feeding device 4 is fed into the apparatus main body 2 and then transported upward, thereby forming an image formed on the upper portion of the paper feeding device 4. After the image is formed by the unit 5 and the fixing device 6, the image is discharged onto a paper discharge tray 7 provided in a space (dent space) below the image reading device 3.

  The image reading device 3 provided on the upper part of the apparatus main body 2 includes a scanner unit 31 that reads an image from a document, and an automatic document transport unit that is provided on the upper part of the scanner unit 31 and transports the document P1 to the scanner unit 31 one by one. ADF (Auto Document Feeder) 32. The scanner unit 31 includes a document table 33 having a platen glass (not shown) on the upper surface side, a light source device 34 that emits light to the document P1, and an image sensor 35 that photoelectrically converts reflected light from the document into image data. And an imaging lens 36 that forms an image of the reflected light on the image sensor 35 and a mirror group 37 that sequentially reflects the reflected light from the original and enters the imaging lens 36. The ADF 32 includes a document placement tray 38 and a document discharge tray 39, and is provided on the upper surface side of the scanner unit 31 so as to be openable and closable with respect to the document table 33.

  In the image reading device 3, when reading a document on a platen glass (not shown) of the document table 33, light is irradiated to the document from a light source device 34 that moves in the sub-scanning direction, and the reflected light is reflected from a mirror group. An image is formed on the image sensor 35 through the image forming lens 37 and the image forming lens 36. As a result, the image sensor 35 generates an electrical signal based on the reflected light from the document and outputs it as image data. On the other hand, when reading a document placed on the document placement tray 38, a light source device 34 and a mirror group 37 fixed at predetermined positions inside the document table 33 are fixed, and a document composed of a plurality of rollers or the like. The document is transported to the reading position by the transport mechanism 40. Accordingly, when the light from the light source device 34 is irradiated onto the original conveyed by the original conveying mechanism 40, the reflected light is imaged on the image sensor 35 and image data is output.

  The image forming unit 5 includes a photosensitive drum 61 that carries toner images of Y (Yellow), M (Magenta), C (Cyan), and K (Key tone) colors, and a photosensitive drum 61 of each color arranged in the horizontal direction. The intermediate transfer belt 53 to which the toner images of each color are transferred from the image forming unit 61, and the photosensitive drums 61 of the respective colors so as to be sandwiched between the photosensitive drum 61 and the intermediate transfer belt 53. A primary transfer roller 54 provided at an opposing position, a drive roller 55 that rotates the intermediate transfer belt 53, a driven roller 56 that rotates when rotation of the drive roller 55 is transmitted through the intermediate transfer belt 53, and intermediate transfer A secondary transfer roller 57 installed at a position facing the driving roller 55 across the belt 53 and a position opposed to the driven roller 56 across the intermediate transfer belt 53. And a cleaner 58, which is provided.

  Further, on the outer peripheral side of the photosensitive drum 61, a charging device 62 that charges the outer peripheral surface of the photosensitive drum 61 by corona discharge, and a developing device that adheres the toner charged by stirring to the outer peripheral surface of the photosensitive drum 61. 63, and a cleaner 64 for removing toner remaining on the outer peripheral surface of the photosensitive drum 61 after the toner image is transferred to the intermediate transfer belt 53. At this time, the photosensitive drum 61 is installed at a position facing the primary transfer roller 54 with the intermediate transfer belt 53 interposed therebetween, and rotates in the clockwise direction in FIG. Around the photosensitive drum 61, a primary transfer roller 54, a cleaner 64, a charging device 62, and a developing device 63 are sequentially arranged along the rotation direction of the photosensitive drum 61.

  Further, the intermediate transfer belt 53 is composed of, for example, an endless belt member having conductivity, and is wound around the drive roller 55 and the driven roller 56 without looseness, so that the intermediate transfer belt 53 is rotated according to the rotation of the drive roller 55. In the counterclockwise direction. Around the intermediate transfer belt 53, along the rotational direction of the intermediate transfer belt 53, the secondary transfer roller 57, the cleaner 58, and the photosensitive drums 61 for each color of YMCK are arranged in order.

  A scanning optical device 8 is installed below the image forming unit 5 as an exposure device for forming an electrostatic latent image on the surface of the photosensitive drum 61 for each color of YMCK in the image forming unit 5. The scanning optical device 8 irradiates the surface of the photosensitive drum 61 for each color of YMCK with laser beams LY, LM, LC, and LK, which are light beams for each color of YMCK. The laser beams LY, LM, LC, and LK irradiated on the surface of the photosensitive drum 61 pass between the charging device 62 and the developing device 63 for each color of YMCK and reach the photosensitive drum 61. The detailed configuration of the scanning optical device 8 will be described later.

  The fixing device 6 includes a heating roller 59 including a halogen lamp that heats the toner image on the recording paper to be fixed, and a pressure roller 60 that presses the recording paper while sandwiching the recording paper together with the heating roller 59. The heating roller 59 may be one in which the surface of the heating roller 59 is heated by generating an eddy current on the surface by electromagnetic induction. A toner replenishing device 8 that contains toner to be replenished to the developing device 63 for each color of YMCK is disposed above the intermediate transfer belt 53. The toner replenishing device 8 is arranged corresponding to each color of YMCK and is connected to the developing device 63 of each color of YMCK via a toner conveying member (not shown), and replenishes toner to the developing device 63 through this toner conveying member.

  As a paper feeding mechanism for taking out the recording paper stored in the paper feeding device 4 one by one, a feeding roller 41 for feeding the recording paper stored in the paper feeding device 4 from the uppermost layer and the fed recording paper one by one. A separation roller pair 42 for separation. Further, the recording paper in the paper feeding device 4 is sent out one by one from the uppermost layer toward the main transport path R0 by the rotational drive of the feeding roller 41 and the separation roller pair 42. On the downstream side of the fixing device 6 in the main transport path R0, a paper discharge roller pair 71 for discharging printed recording paper is disposed. The printed recording paper is discharged to the paper discharge tray 7 by the rotation drive of the paper discharge roller pair 71.

  Further, in the apparatus main body 2 of the image forming apparatus 1 configured as described above, there is further provided a circulation conveyance unit R1 for performing double-sided printing by reversing the recording paper after single-sided printing. The discharge roller pair 71 is configured to be able to rotate forward and backward, so that the recording sheet can be discharged to the discharge tray 7 outside the apparatus main body 2 or switched back by the forward and reverse rotation of the discharge roller pair 71. Or reversely) and return to the circulation conveyance path R1 in the apparatus main body 2.

  A printing operation by the image forming apparatus 1 will be briefly described. The image forming apparatus 1 receives a start signal, an image signal, and the like and starts a printing operation. When the printing operation starts, the recording paper fed out from the paper feeding device 4 is transported to the image forming unit 5 along the main transport path R0. In this image forming unit 5, the surface of the photosensitive drum 61 charged by the charging device 62 is irradiated with laser beams LY, LM, LC, and LK from the scanning optical device 8, and electrostatic latent images corresponding to images of YMCK colors. Is formed on the surface of the photosensitive drum 61.

  The toner charged by the developing device 63 is transferred to the surface of the photosensitive drum 61 on which the electrostatic latent image is formed, and a toner image is formed on the photosensitive drum 61. The toner image carried on the surface of the photosensitive drum 61 is transferred to the intermediate transfer belt 53 by the electrostatic force of the primary transfer roller 54 when coming into contact with the intermediate transfer belt 53. In addition, a toner image in which each color of YMCK is overlapped is formed. On the other hand, the untransferred toner remaining on the photosensitive drum 61 having the toner image transferred to the intermediate transfer belt 53 is scraped off by the cleaner 64 and removed from the photosensitive drum 61.

  The toner image transferred to the intermediate transfer belt 53 is moved to the transfer position where the intermediate transfer belt 53 contacts the secondary transfer roller 57 by the rotation of the intermediate transfer belt 53 by the driving roller 55 and the driven roller 56, and on the main transport path R0. The image is transferred onto a recording sheet conveyed to the transfer position. Untransferred toner remaining on the intermediate transfer belt 53 that has transferred the toner image onto the recording paper is scraped off by the cleaner 58 and removed from the intermediate transfer belt 53. Further, the recording paper on which the toner image is transferred at the contact position with the secondary transfer roller 57 is conveyed to the fixing device 6.

  The recording paper on which the unfixed toner image is placed on one side is heated by the heating roller 59 and pressed by the pressure roller 60 when passing through the fixing position of the fixing device 6, so that the unfixed toner image is applied to the paper surface. It is fixed. In the case of single-sided printing, the recording paper after toner image fixing (after single-sided printing) is discharged to the paper discharge tray 7 by the paper discharge roller pair 71. On the other hand, in the case of double-sided printing, the recording paper after single-sided printing is transported to the circulation transport path R1 for double-sided printing, turned over, and returned to the main transport path R0, whereby recording is performed by the image transfer unit 5 and the fixing device 6. After the toner image is transferred and fixed on the other side of the paper, it is discharged to the paper discharge tray 7.

<Configuration of scanning optical device>
The configuration of the scanning optical device 8 in the image forming apparatus of FIG. 1 will be described below with reference to the drawings. FIG. 2 is a schematic cross-sectional view showing the internal configuration of the scanning optical device 8, and FIG. 3 is a plan view showing the internal configuration of the scanning optical device 8. 4 is an enlarged view showing the configuration of the main part of the light source unit and the optical scanning unit of the scanning optical device 8, and FIG. 5 is a schematic perspective view showing the configuration of the light source unit installed in the light source unit. . In the plan view of FIG. 3, the upper cover is removed to clarify the internal structure. Further, in the following description, when using terms indicating a specific direction or position (for example, “left / right”, “up / down”, “front / rear”) as necessary, the front of the paper in FIG. This is based on this. That is, the main scanning direction corresponds to the “front-rear direction” with reference to FIG.

  As shown in FIGS. 3 and 4, the scanning optical device 8 includes a housing whose side walls 82 f, 82 b, 82 l, and 82 r are erected at the front and rear, left and right peripheral ends of a substantially rectangular bottom plate 81 and covered with an upper lid 83. Each optical member described later is installed in the body 80. The scanning optical device 8 includes a light scanning unit 84 in which the scanner unit 400 is installed and a light source unit 85 in which a light source unit 500 described later is installed on the left side wall 82 l side of the housing 80. The light source unit 85 is provided on the front side wall 82 f side, and the optical scanning unit 84 is provided so as to be adjacent to the rear side of the light source unit 85.

  A long scanning lens 201 composed of an fθ lens is installed at a position facing the right side of the optical scanning unit 84, and a long length composed of an fθ lens is also disposed on the right side of the scanning lens 201. A scanning lens 202 is installed. Longer reflecting mirrors 203y, 203m, 203c, and 203k are fixed in order toward the right side further to the right side from the installation position of the scanning lens 202. The reflecting mirrors 203y, 203m, 203c, and 203k have laser beams LY, LM, LC, and LK that are scanned by the optical scanning unit 84 and transmitted through the scanning lenses 201 and 202 by setting the vertical height positions to different positions. Receive each.

  Scanning lenses 205y, 205m, 205c, and 205k that transmit the laser beams LY, LM, LC, and LK reflected by the reflecting mirrors 203y, 203m, 203c, and 203k are respectively provided above the reflecting mirrors 203y, 203m, 203c, and 203k. It is fixed. That is, the long scanning lenses 205y, 205m, 205c, and 205k are installed on the optical paths of the laser beams LY, LM, LC, and LK that reflect the reflecting mirrors 203y, 203m, 203c, and 203k, respectively. On the upper left side of each of the scanning lenses 205y, 205m, and 205c, the elongated reflecting mirrors 204y, 204m, and 204c are positioned to receive the laser beams LY, LM, and LC transmitted through the scanning lenses 205y, 205m, and 205c, respectively. Installed. Each of the reflecting mirrors 203y, 203m, 203c, 203k, 204y, 204m, and 204c is installed with its mirror surface inclined at a predetermined angle.

  Further, the upper lid 83 covering the upper side of the casing 80 is a dust-proof fitting fitted into an opening for emitting each of the laser beams LY, LM, LC reflecting the reflecting mirrors 204y, 204m, 204c to the outside of the apparatus. Window glasses 231y, 231m, and 231c, and a dust-proof window glass 231k fitted into an opening for emitting laser light LK transmitted through the scanning lens 205k to the outside of the apparatus are provided. Each of the window glasses 231y, 231m, 231c, and 231k is formed in a long shape, and is disposed on the reflecting mirrors 204y, 204m, and 204c and the scanning lens 205k.

  As shown in FIGS. 3 and 4, the optical scanning unit 84 is provided with a slit 404 at a position facing the scanning lens 201, and emits laser light LY, LM, LC, LK to the scanning lens 201. The scanner unit 400 installed in the optical scanning unit 84 includes a motor 402 configured on the substrate 401 and a polygon mirror 403 that is supported by the rotation shaft of the motor 402. By configuring the optical scanning unit 84 in this way, the laser beams LY, LM, LC, and LK emitted from the light source unit 85 are applied to the polygon mirror 403 that is rotated by the motor 402. Then, the laser light LY, LM, LC, and LK reflected and scanned by the polygon mirror 403 is irradiated to the scanning lens 201 through the slit 404. Further, in a region of the upper lid 83 that covers the upper side of the optical scanning unit 84, a radiation fin 404 that dissipates heat due to the rotation of the motor 402 and the polygon mirror 403 is installed.

  As shown in FIGS. 4 and 5, the light source unit 85 includes laser diodes 501y, 501m, 501c, and 501k, collimator lenses 502y, 502m, 502c, and 502k, reflection mirrors 503y, 503m, 503c, 503k, and 504, and cylindrical. A lens 505 includes a light source unit 500 fixed on a holding member 506. The holding member 506 in the light source unit 500 is vertically provided with respect to the optical system holding unit 561 from the side of the optical system holding unit 561 and a plate-like optical system holding unit 561 that is screwed to the bottom plate 81 with screws 507. And a plate-like light source holding part 562.

  The light source holding unit 562 is inclined and arranged from the left rear to the right front, and the laser diodes 501y, 501m, 501c, and 501k are fixed along the direction away from the optical scanning unit 84. In the optical system holding unit 561, the collimator lenses 502y, 502m, 502c, and 502k are fixed at positions facing the laser diodes 501y, 501m, 501c, and 501k, respectively. In the optical system holding unit 561, reflecting mirrors 503y, 503m, 503c, and 503k are provided upright at positions opposite to the light source holding unit 562 of the collimator lenses 502y, 502m, 502c, and 502k. In the optical system holding unit 561, the reflection mirror 504 is erected on the extended line where the reflection mirrors 503y, 503m, 503c, and 503k are arranged, and the optical system is held more than the fixed position of the reflection mirrors 503y, 503m, 503c, and 503k. A cylindrical lens 505 is erected at a position away from the portion 561.

  The reflection mirrors 503y, 503m, 503c, and 503k are erected from the optical system holding unit 561 so as to be inclined at the same angle with respect to the optical axes of the collimator lenses 502y, 502m, 502c, and 502k. Further, the collimator lenses 502y, 502m, 502c, and 502k are respectively disposed from the left rear to the right front, and the reflection mirrors 503y, 503m, 503c, 503k, and 504 are respectively disposed from the left rear to the right front. The A cylindrical lens 505 is arranged on the left rear side with respect to the reflection mirror 504 on a straight line connecting the reflection mirror 504 and the polygon mirror 403.

  The optical system holding unit 561 includes two through holes 563 into which screws 507 are inserted in positions near the connection portion with the light source holding unit 562 and on both sides of the light source holding unit 562, and the light source holding unit. Another through-hole 564 into which the screw 508 is inserted is provided at a position away from 562. As a result, the screws 507 and 508 pass through the optical holding portion 561 and are screwed into the bottom plate 81 of the housing 80, the optical system holding portion 561 is fixed to the bottom plate 81, and the holding member 506 is fixed to the housing 80. Is done.

  At this time, the screw 507 that is screwed fixes both sides of the attachment portion (root) of the light source holding unit 562 to the optical system holding unit 561, so that the optical system holding unit 561 is deformed to the light source holding unit 562. The influence can be suppressed. That is, two lines are provided on both sides of the light source holding unit 562 so that the straight line connecting the fixing points by the screws 507 on both sides of the light source holding unit 562 approaches the side of the optical system holding unit 561 where the light source holding unit 562 is erected. A through hole 563 is provided.

  Furthermore, the holding member 506 is made of a resin material, and for example, may be formed by molding so that the optical system holding unit 561 and the light source holding unit 562 are integrated. Even in the holding member 506 made of the resin material in this way, a part of the fixing point by the screw 507 is arranged on both sides of the connection portion between the light source holding unit 562 and the optical system holding unit 561 as described above. Thus, the rigidity of the holding member 506 can be increased, and the influence of thermal deformation can be reduced. This eliminates the need to provide ribs on the holding member 506 and eliminates the need for a housing. Therefore, not only can the amount of the resin material used for molding the holding member 506 be reduced, but the above-described optical components can be easily mounted, and the mounting accuracy of the optical components can be maintained with high accuracy.

  As shown in FIGS. 5 and 6, the laser diodes 501y, 501m, 501c, and 501k fixed to the light source holding portion 562 of the holding member 506 are inserted into the element holder 511 to be light emitting element units 512y, 512m, 512c, and 512k. Is configured. The light emitting element units 512y, 512m, 512c, and 512k are installed such that the light emitting sides of the laser diodes 501y, 501m, 501c, and 501k face the light incident sides of the collimator lenses 502y, 502m, 502c, and 502k. That is, the light emitting surfaces of the laser diodes 501y, 501m, 501c, and 501k are installed at a position facing the through hole (light emitting element installation unit) 565 of the light source holding unit 562 so that the laser beam can pass therethrough. Then, the light source holding part 562 and the element holder 511 are screwed together, whereby the light emitting element unit 512 is fixed to the light source holding part 562. Accordingly, the laser diodes 501y, 501m, 501c, and 501k and the collimator lenses 502y, 502m, 502c, and 502k are installed at a predetermined distance. At the same time, the optical axes of the laser diodes 501y, 501m, 501c, and 501k coincide with the optical axes of the collimator lenses 502y, 502m, 502c, and 502k.

  In the light source unit 85 configured in this manner, each of the multi-beam type laser diodes 501y, 501m, 501c, and 501k fixed to the light source holding unit 562 oscillates two laser beams to generate laser beams LY and LM. , LC and LK are emitted. The laser beams LY, LM, LC, and LK emitted from the laser diodes 501y, 501m, 501c, and 501k are transmitted through the collimator lenses 502y, 502m, 502c, and 502k, respectively, to become parallel beams, and the reflection mirrors 503y and 503m. , 503c, and 503k. The reflecting mirrors 503y, 503m, 503c, and 503k are inclined at 45 degrees with respect to the optical axis of the collimator lenses 502y, 502m, 502c, and 502k, for example, so that the collimator lenses 502y, 502m, and 502c. , 502k, laser beams LY, LM, LC, and LK are reflected at right angles.

  The laser beams LY, LM, LC, and LK reflected from the reflection mirrors 503y, 503m, 503c, and 503k are further reflected by the reflection mirror 504 and irradiated toward the polygon mirror 403. At this time, the laser beams LY, LM, LC, and LK reflected by the reflection mirror 504 pass through the cylindrical lens 505, and are condensed at substantially the same position on each mirror surface of the polygon mirror 403.

  The laser beams LY, LM, LC, and LK emitted from the light source unit 85 are deflected and scanned by the rotation of the polygon mirror 403 of the optical scanning unit 84. At this time, the light beams of the laser beams LY, LM, LC, and LK reflected from the polygon mirror 403 are positioned in the order of LY, LM, LC, and LK from the bottom plate 81 of the housing 80 toward the upper lid 83. When the laser beams LY, LM, LC, and LK are sequentially transmitted through the scanning lenses 201 and 202, they are reflected by the reflecting mirrors 203y, 203m, 203c, and 203k.

  The laser beams LY, LM, and LC reflected from the reflecting mirrors 203y, 203m, and 203c are folded upward on the left side by the reflecting mirrors 203y, 203m, and 203c, respectively, and transmitted through the scanning lenses 205y, 205m, and 205c configured by fθ lenses. After that, the light is reflected by the reflecting mirrors 204y, 204m, and 204c, and is emitted to the outside from the window glasses 231y, 231m, and 231c of the upper lid 23. Further, the laser beam LK reflected by the reflecting mirror 203k is folded upward by the reflecting mirror 203k, passes through the scanning lens 205k constituted by an fθ lens, and is emitted to the outside from the window glass 231k of the upper lid 23. As a result, the laser beams LY, LM, LC, and LK are emitted from the scanning optical device 8 as light beams applied to the YMCK color photosensitive drums 61.

  A more detailed configuration of the light source unit 500 in the scanning optical device 8 configured as described above will be described in the following embodiments.

<First Embodiment>
A light source unit according to a first embodiment of the present invention will be described below with reference to the drawings. FIG. 7 is a front view showing the configuration of the holding member in the light source unit of the present embodiment, and FIG. 8 is a front view showing the configuration of the light source unit of the present embodiment. 7 and 8, the same parts as those in FIGS. 5 and 6 are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 7, in the light source unit 500 of this embodiment, in the light source holding part 562a of the holding member 506a, through holes (light emitting element installation parts) 565y and 565m from the side close to the light scanning part 84 (see FIG. 4). , 565c, 565k are provided side by side. The through-holes 565y, 565m, 565c, and 565k have the through-hole 565y closest to the optical scanning unit 84 serving as a heat source as the lowest position, and the through-hole 565k farthest from the optical scanning unit 84 as the highest position. The heights are provided in the order of 565y, 565m, 565c, and 565k. Screw holes (light emitting element fixing portions) 566 into which screws 567 (see FIG. 8) are screwed are provided above and below the through holes 565y, 565m, 565c, and 565k.

  As shown in FIG. 8, the light source holding part 562a shown in FIG. 7 includes light-emitting element units 512y, 512m, 512c, and 512k formed by laser diodes 501y, 501m, 501c, and 501k inserted in the element holder 511. , 565m, 565c, and 565k. At this time, the element holder 511 is screwed by the light source holding part 562 with the screw 567, and the installation positions of the light emitting element units 512y, 512m, 512c, and 512k are determined. Accordingly, the optical axes of the laser diodes 501y, 501m, 501c, and 501k are perpendicular to the optical axes so as to coincide with the optical axes of the collimator lenses 502y, 502m, 502c, and 502k (see FIG. 5). The positions of the laser diodes 501y, 501m, 501c, and 501k in the surface direction are determined.

  Then, the position of the light emitting surface of the laser diodes 501y, 501m, 501c, and 501k is specified by the element holder 511 coming into contact with the light source holding part 562a. Accordingly, the distances between the laser diodes 501y, 501m, 501c, and 501k and the collimator lenses 502y, 502m, 502c, and 502k are distances corresponding to the focal lengths of the collimator lenses 502y, 502m, 502c, and 502k. The position in the optical axis direction is determined.

  In this way, when the positions of the laser diodes 501y, 501m, 501c, and 501k are adjusted by the light source holding portion 562a, the screw 567 that penetrates the element holder 511 of the light emitting element units 512y, 512m, 512c, and 512k is inserted into the screw hole 566. Screw in. As a result, the light emitting element units 512y, 512m, 512c, and 512k are screwed to the light source holding portion 562a, and the laser diodes 501y, 501m, 501c, and 501k are fixed to the light source unit 500.

  As described above, in the light source unit 500 of the present embodiment, the laser diodes 501y, 501m, 501c, and 501k are made higher in order from the side closer to the optical scanning unit 84 where the respective height positions are heat sources by the light source holding unit 562a. Fix so that it becomes. Since the light source holding portion 562a is erected from the optical system holding portion 561 (see FIG. 6), only the connection portion with the optical system holding portion 561 is fixed. Therefore, when the light source holding unit 562a is deformed by the influence of heat generated by the light scanning unit 84 (see FIG. 4), the light source holding unit 562a is deformed so as to be inclined with respect to the height direction.

  The inclination of the light source holding unit 562a increases as the distance from the heat source increases. However, by installing the laser diode 501y close to the heat source at a position close to the connection portion with the optical system holding unit 561, the laser diode 501y is deformed due to thermal deformation. Misalignment can be suppressed. Further, since the height positions of the laser diodes 501y, 501m, 501c, and 501k are set to be lower as they approach the heat source, it is possible to minimize each positional deviation due to thermal deformation. Therefore, it is possible to suppress the influence due to the thermal deformation of the light source unit 500 and maintain the optical performance set with high accuracy in the initial state.

<Second Embodiment>
A light source unit according to a second embodiment of the present invention will be described below with reference to the drawings. FIG. 9 is a front view illustrating the configuration of the holding member in the light source unit of the present embodiment, and FIG. 10 is a front view illustrating the configuration of the light source unit of the present embodiment. In the configuration of FIGS. 9 and 10, the same components as those in FIGS. 7 and 8 are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 9, in the light source unit 500 of the present embodiment, in the light source holding part 562b of the holding member 506b, through holes 565y, 565m, which are the same as the light source holding part 562a (see FIG. 7) in the first embodiment. 565c and 565k are provided, and screw holes 566 are provided on the left and right sides of the through holes 565y, 565m, 565c and 565k. Accordingly, as shown in FIG. 10, each of the light emitting element units 512y, 512m, 512c, and 512k is screwed to the light source holding portion 562b by screws 567 inserted on the left and right of the laser diodes 501y, 501m, 501c, and 501k. .

  In the light source unit 500 of the present embodiment, as described above, the screws 566 for fixing the light emitting element units 512y, 512m, 512c, and 512k are inserted to the left and right of the laser diodes 501y, 501m, 501c, and 501k, respectively. Become. Therefore, compared with the configuration of the first embodiment, the installation positions of the laser diodes 501y, 501m, 501c, and 501k can be lowered toward the optical system holding portion 561. That is, the height positions of the laser diodes 501y, 501m, 501c, and 501k approach the connection portion with the optical system holding unit 561. Thereby, since the light source unit 500 of this embodiment can further suppress the positional deviation of the laser diodes 501y, 501m, 501c, and 501k due to thermal deformation, the ability to maintain the optical performance is increased.

<Third Embodiment>
A light source unit according to a third embodiment of the present invention will be described below with reference to the drawings. FIG. 11 is a front view showing the configuration of the light source unit of the present embodiment. In the configuration of FIG. 11, the same parts as those of the configuration of FIG.

  As shown in FIG. 11, the light source unit 500 of the present embodiment includes an optical system holding unit 561 and a light source holding unit 562 c of the holding member 506 c, in addition to the light source holding unit 562 b (see FIG. 9) in the second embodiment. It becomes the structure which added the notch part 569 used as the notch toward the lower side from the edge part 568 used as the reverse side of this connection part. In the configuration of FIG. 11, the notch 569 is configured as a cut to a position higher than the height position of the laser diode 501y at a position between the light emitting element units 512y and 512m arranged side by side in FIG.

  With this configuration, it is possible to prevent the deformation in the installation area of the laser diode 501y that is most affected by the thermal deformation from affecting the installation areas of the laser diodes 501m, 501c, and 501k. That is, in the light source holding part 562c at the time of thermal deformation, the inclination angle is different between the installation region 621 of the laser diode 501y and the installation region 622 of the laser diodes 501m, 501c, and 501k. Accordingly, since the inclination in the installation region 622 of the laser diodes 501m, 501c, and 501k far from the heat source is reduced, the positional deviation of the laser diodes 501m, 501c, and 501k installed at a position higher than the laser diode 501y can be further reduced.

  In the present embodiment, the light source holding part 562c has been described with reference to the configuration example in which the light source holding part 562a is provided with the notch 568. However, the light source holding part 562a (see FIG. 7) in the first embodiment is notched. A configuration may be employed in which the portion 569 is provided.

  Further, as shown in FIG. 12, the notch 569 may be provided between the installation regions of the laser diodes 501m, 501c, and 501k. At this time, for example, the notch 569 provided between the laser diodes 501m and 501c is cut to a position higher than the height position of the laser diode 501m, and the notch provided between the laser diodes 501c and 501k. The part 569 may be cut to a position higher than the height position of the laser diode 501c. Furthermore, not all the three notches 569 shown in FIG. 12 are provided, and any one notch 569 may be provided.

  In each of the above-described embodiments, the optical members are installed so that the height positions of the laser beams LY, LM, LC, and LK increase in the order of LY, LM, LC, and LK. It is not limited by the combination of the positions. That is, the installation positions of the optical members are determined so that the positional relationship of the laser diodes 501y, 501m, 501c, and 501k in the light source holding unit 562 and the positional relationship of the YMCK photosensitive drums 61 are relatively matched. As long as it is a thing, you may match | combine with another combination in the height position of laser beam LY, LM, LC, LK.

  In the light source unit 500 in each of the above-described embodiments, the reflection mirrors 503m, 503c, and 503k (see FIG. 5) are lasers that reflect the reflection mirrors 503y, 503m, and 503c (see FIG. 5) arranged on the upper left of the respective mirrors. The height position is set and installed so that light passes through the lower side. As a result, the laser beam LY that reflects the reflection mirror 503y passes through the lower side of the reflection mirrors 503m, 503c, and 503k, and the laser beam LM that reflects the reflection mirror 503m passes through the lower side of the reflection mirrors 503c and 503k. The laser light LC reflected from the reflection mirror 503c is transmitted below the reflection mirror 503k, and each of the laser lights LY, LM, LC, and LK is incident on the reflection mirror 504.

  The image forming apparatus according to the present invention may be an MFP (Multifunction Peripheral) having a copy function, a scanner function, a printer function, and a fax function as long as it includes each of the light source units in each of the above-described embodiments. It may be a printer, a copier, a facsimile, or the like. In addition, the structure of each part is not limited to embodiment of illustration, A various change is possible in the range which does not deviate from the meaning of this invention.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Apparatus main body 3 Image reading apparatus 4 Paper feeding apparatus 5 Image forming unit 6 Fixing apparatus 7 Paper discharge tray 8 Scanning optical apparatus 80 Case 81 Bottom plate 82f, 82b Side plate (front and rear)
82l, 82r side plate (left, right)
83 Upper lid 84 Optical scanning unit 85 Light source unit 201, 202 Scanning lens 203y, 203m Reflective mirror 203c, 203k Reflective mirror 204y, 204m Reflective mirror 204c Reflective mirror 205 Scanning lens 205y, 205m Scanning lens 205c, 205k Scanning lens 231y, 231m Window glass 231c, 231k Window glass 400 Scanner unit 401 Substrate 402 Motor 403 Polygon mirror 404 Radiation fin 500 Light source unit 501y, 501m Laser diode 501c, 501k Laser diode 502y, 502m Collimator lens 502c, 502k Collimator lens 503y, 503m Reflective mirror 503c 503k reflection mirror 504 reflection mirror 505 cylindrical lens 506 Holding member 506a to 506c Holding member 511 Element holder 512y, 512m Light emitting element unit 512c, 512k Light emitting element unit 507,508 Screw 561 Optical system holding part 562 Light source holding part 562a to 562c Light source holding part 563, 564 Through hole 565 Through hole ( (Light emitting element installation part)
565y, 565m Through hole (light emitting element installation part)
565c, 565k Through hole (light emitting element installation part)
566 Screw hole (light emitting element fixing part)
567 Screw 568 End 569 Notch 621, 622 Installation area

Claims (8)

A plurality of light emitting elements that irradiate light beams, an optical member that guides a plurality of light beams emitted from each of the plurality of light emitting elements to irradiate an external optical scanning unit, and a light source holding that holds the light source unit And an optical system holding unit that holds the optical member, and a light source unit in which the optical system holding unit is fixedly attached to a scanning optical device having the optical scanning unit that deflects and scans a light beam. And
The light source holding unit includes a surface that is erected from a side of the optical system holding unit and is perpendicular to the optical axis of the light beam emitted from the light emitting element,
The plurality of light emitting elements held by the light source holding unit are fixed side by side in a direction parallel to the surface of the optical system holding unit, and a height position thereof is along a direction away from the optical scanning unit. A light source unit that is arranged to be higher. The light source holding unit includes a light emitting element installation unit in which the light emitting element is installed, and a light emitting element fixing unit that fixes the light emitting element installed in the light emitting element installation unit,
2. The light source unit according to claim 1, wherein when the direction in which the plurality of light emitting elements are arranged is a left-right direction, the light emitting element fixing portions are arranged on both left and right sides of the light emitting element installation portion.   The light source holding part has a notch part that cuts downward from an end opposite to the connection part to the optical system holding part at at least one position between the fixed light emitting elements. The light source unit according to claim 1, wherein the light source unit is a light source unit.   The said optical member is equipped with the several collimator lens by which a light-incidence surface is arrange | positioned in the position which opposes the irradiation surface of each of these light emitting elements. Light source unit.   The light source unit according to claim 1, wherein each of the light source holding part and the optical system holding part is integrally formed of a resin material.   6. The light source according to claim 1, wherein a part of a fixed position to the scanning optical device is in the vicinity of both sides of a connection portion between the light source holding unit and the optical system holding unit. unit. A scanning optical device comprising: a light source unit that emits a plurality of light beams; and an optical scanning unit that deflects and scans each of the plurality of light beams emitted from the light source unit,
A scanning optical device, wherein the light source unit according to claim 1 is installed in the light source unit.   8. An image forming apparatus comprising: the scanning optical device according to claim 7; and a plurality of photosensitive drums that are each irradiated with a plurality of light beams from the scanning optical device to form an electrostatic latent image on the surface. apparatus.

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