JP2012150132A - Mechanism for adjusting and fixing light-emitting element, optical scanner, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mechanism for adjusting and fixing a light-emitting element for preventing an optical axis or beam pitch of a light-emitting element from changing between adjustment time and fixing time.SOLUTION: In a mechanism for adjusting and fixing a light-emitting element, a light-emitting element having a plurality of light-emitting points is rotated around an optical axis to adjust a distance between respective light-emitting points and fix the light-emitting element to a housing. The mechanism includes: a holding member 22 that holds the light-emitting element; an attachment hole 13 having a reference surface 7b with which the light-emitting element is attached to the housing; and a holding part 11 that holds the holding member 22 so that the light-emitting element is rotatably in contact with the reference surface 7b. The light-emitting element is rotated and adjusted in a state where the holding member 22 is held by the holding part 11 before being fixed to the housing.

Description

  The present invention relates to an optical scanning device used in a writing optical system of an image forming apparatus such as a digital copying machine or a laser printer, and more particularly to a position adjustment and fixing technique of a light emitting element having a plurality of light beams.

  2. Description of the Related Art Conventionally, an image forming apparatus using a laser as a light source in electrophotographic image formation is widely known. As a technique for adjusting the pitch of a beam emitted from a plurality of laser diodes, a light source unit on which laser diodes are mounted. For example, "Patent Document 1" and "Patent Document 2" disclose a technique for fixing a light source unit to a light source mounting portion with a screw after adjusting by rotating.

  However, in the above-described technique, it is necessary to press the light source unit against the reference surface of the light source mounting portion with a rotating jig at the time of rotation adjustment. At this time, the light source mounting portion falls down due to the pressing. When adjustment and fixing are performed in such a state where the tilt has occurred, the tilt of the light source mounting part returns to its original state when the rotating jig is removed after adjustment and fixing. There is a problem that the amount of tilting is different, the distance and position of the projected light is shifted due to the tilting of the optical axis, and the writing image quality is lowered in the writing system.

  Therefore, as a technique for preventing the light source mounting portion from collapsing, a reinforcing rib is disposed on the side of the opening provided on the side wall of the optical box to which the light source unit is mounted, thereby locally reinforcing the rigidity of the side wall of the optical box. The technique is disclosed in, for example, “Patent Document 3”.

  However, in the technique disclosed in “Patent Document 3”, the rigidity is locally strengthened and the influence of the collapse is not completely eliminated. The accuracy of the beam pitch on the photoconductor has several error tolerances. Sufficient accuracy could not be achieved because it had to be controlled very strictly at μm or less.

  An object of the present invention is to solve the above-described problems and provide an adjustment fixing structure for a light emitting element capable of preventing the optical axis and beam pitch of the light emitting element from changing during adjustment and fixing.

  According to a first aspect of the present invention, a light emitting element that fixes a light emitting element to a housing by adjusting a distance between the light emitting points by rotating a light emitting element having a plurality of light emitting points around an optical axis of the light emitting point. In the adjusting and fixing structure, the light emitting element is held by a holding member, and the housing has a mounting hole having a reference surface to which the light emitting element is attached and the light emitting element is rotatable in a state where the light emitting element is in contact with the reference surface. A holding portion for holding the holding member, and the light emitting device is fixed to the housing after the light emitting device is rotationally adjusted in a state where the holding member is held by the holding portion.

  According to a second aspect of the present invention, in the adjustment fixing structure for a light emitting element according to the first aspect, the holding portion is further formed so that the thickness thereof is sufficiently thinner than the thickness of the housing.

  According to a third aspect of the present invention, in the adjustment fixing structure for a light emitting device according to the first or second aspect, the holding member further has a flange portion formed by bending.

  According to a fourth aspect of the present invention, in the adjustment fixing structure for a light emitting device according to any one of the first to third aspects, the holding member further includes a mounting portion to which a rotating jig used during adjustment is mounted. Features.

  According to a fifth aspect of the present invention, in the light-emitting element adjustment fixing structure according to any one of the first to fourth aspects, the holding member further holds the light-emitting element by press-fitting the light-emitting element. It is characterized by.

  According to a sixth aspect of the present invention, in the adjustment fixing structure of the light emitting element according to the fifth aspect, the light emitting element is further press-fitted into the holding member while being inclined at a predetermined angle according to an image pitch.

  A seventh aspect of the invention is an optical scanning device having the light emitting element adjusting and fixing structure according to any one of the first to sixth aspects.

  The invention according to claim 8 is an image forming apparatus having the optical scanning device according to claim 7.

  According to the present invention, it is possible to prevent the position of the scanning light beam from being changed due to the tilt of the side wall of the housing, so that if the optical writing system is used, the stability of the scanning line can be obtained, so that good image quality can be obtained. .

1 is a schematic front view of an image forming apparatus to which an embodiment of the present invention can be applied. It is the schematic explaining the optical scanning device used for one Embodiment of this invention. It is the schematic explaining adjustment of the light emitting element in one Embodiment of this invention. It is the schematic explaining the adjustment fixing structure of the light emitting element used for one Embodiment of this invention. It is the schematic explaining the light source unit used for one Embodiment of this invention. It is the schematic explaining the adjustment fixation procedure of the light emitting element in one Embodiment of this invention. It is the schematic explaining the adjustment fixation procedure of the light emitting element in one Embodiment of this invention. It is the schematic explaining the adjustment fixation procedure of the light emitting element in one Embodiment of this invention. It is the schematic explaining the adjustment fixation procedure of the light emitting element in one Embodiment of this invention. It is the schematic which shows the problem of a prior art. It is the schematic explaining attachment of the light source unit used for the modification of one Embodiment of this invention. It is the schematic explaining attachment of the light source unit used for the modification of one Embodiment of this invention. It is the schematic explaining attachment of the light source unit used for the other modification of one Embodiment of this invention. It is the schematic explaining attachment of the light source unit used for the other modification of one Embodiment of this invention. It is the schematic explaining the light source unit used for the further another modification of one Embodiment of this invention. It is the schematic explaining the holding | maintenance part used for the other modification of one Embodiment of this invention.

  FIG. 1 shows an image forming apparatus employing one embodiment of the present invention. In the figure, an image forming apparatus 500 includes an optical scanning device 100, four photosensitive drums 30A, 30B, 30C, and 30D, an intermediate transfer belt 40, a paper feed tray 60, a paper feed roller 54, registration roller pairs 52 and 56, A fixing unit 50, a paper discharge roller pair 58, a control unit (not shown), an apparatus main body 501, and the like are included. On the upper surface of the apparatus main body 501, a paper discharge tray 501a for discharging printed paper is provided, and the optical scanning device 100 is disposed below the paper discharge tray 501a. Based on image information sent from an image reading device (not shown) or an external device, the optical scanning device 100 emits a black image component laser beam to the photosensitive drum 30A, and a cyan image component laser to the photosensitive drum 30B. The light is scanned with the laser light of the magenta image component on the photosensitive drum 30C, and the laser light of the yellow image component is scanned on the photosensitive drum 30D.

  The photosensitive drums 30A, 30B, 30C, and 30D are juxtaposed below the optical scanning device 100, and are each driven to rotate clockwise in FIG. 1 by driving means (not shown). Around the photosensitive drum 30A, a charging unit 32A for charging the surface of the photosensitive drum 30A with a predetermined voltage, a developing unit 33A having a cartridge filled with black component toner, a developing roller, and the like, and the photosensitive drum 30A A cleaning unit 31A that has a cleaning blade in contact with the surface and cleans the surface of the photosensitive drum 30A is disposed. A similar configuration is also arranged around the other photosensitive drums 30B, 30C, and 30D except for the color of the toner stored in the developing means, and cyan toner is supplied to the developing means 33C in the developing means 33B. Is a magenta component toner, and the developing means 33D stores a yellow component toner.

  The endless belt-shaped intermediate transfer belt 40 is stretched around driven rollers 40a and 40c and a driving roller 40b, and the upper surface thereof is disposed so as to be in contact with each of the photosensitive drums 30A, 30B, 30C and 30D. When 40b is driven to rotate, it is driven to travel in the direction of the arrow in FIG. At a position facing the driven roller 40c via the intermediate transfer belt 40, there is a transfer charger 48 as a transfer means for applying a voltage having a polarity opposite to that of the charging means 32A, 32B, 32C, 32D to the intermediate transfer belt 40. The intermediate transfer belt 40 is disposed close to the intermediate transfer belt 40 at a predetermined distance.

  A sheet feeding tray 60 for storing a plurality of sheets 61 is disposed below the intermediate transfer belt 40, and a sheet feeding unit for separating and feeding the sheets 61 one by one at the upper right side of the sheet feeding tray in FIG. A roller 54 is provided. The sheet 61 fed from the sheet feed tray 60 by the sheet feed roller 54 is fed toward the gap between the transfer belt 40 and the transfer charger 48 via the registration roller pair 56.

  A fixing unit 50 comprising a roller pair of a pressure roller and a heating roller is disposed on the downstream side in the sheet conveyance direction of the proximity portion between the transfer belt 40 and the transfer charger 48. The fixing means 50 fixes the toner image transferred onto the paper 61 by heat and pressure, and the fixed paper 61 is sent to a paper discharge roller pair 58 comprising a pair of rollers via a registration roller pair 52. The paper is sequentially discharged onto the paper discharge tray 501a.

  As shown in FIG. 2, the optical scanning device 100 generates two laser beams P1 and P2 which are a plurality of light emitting points from the light emitting element 1, and parallelizes the beams P1 and P2 by the collimator lens 2, respectively. Then, the light is irradiated onto the reflection surface of the polygon mirror 4 serving as scanning means via the cylindrical lens 3, and formed on the photosensitive drum 30 via the fθ lens 5 and the exit window 6. At this time, the laser beam P guided onto the photosensitive drum 30 is scanned in the main scanning direction Q1 with the predetermined pitch X1 in the sub-scanning direction Q2 orthogonal to the main scanning direction Q1 by the rotation of the polygon mirror 4. In the laser scanning optical device using the light emitting element 1, writing is performed by simultaneously scanning the photosensitive drum 30 over many rows.

  The collimating lens 2, the cylindrical lens 3, the polygon mirror 4, the fθ lens 5 and the like are attached to the bottom wall of the optical housing 7 attached to the apparatus main body 501, and the light emitting element 1 is attached to the side wall 7 a of the optical housing 7. After each optical component is attached to the optical housing 7, the upper opening of the optical housing 7 is closed by a lid member (not shown). The attachment of the light emitting element 1 to the side wall 7a will be described later.

The operation of the image forming apparatus 500 including the optical scanning device 100 described above will be described below.
When image information is sent from an external device or the like, the laser beams P1 and P2 emitted from the light emitting element 1 are condensed on the reflecting surface of the polygon mirror 4 by the collimating lens 2 and the cylindrical lens 3. The laser beams P1 and P2 deflected by the polygon mirror 4 are condensed on the surface of the photosensitive drum 30A through the fθ lens 5. Similarly, laser beams emitted from other light emitting elements (not shown) are respectively deflected by polygon mirrors and condensed on the surfaces of the other photosensitive drums 30B, 30C, and 30D. At this time, the laser beam from the optical scanning device 100 is incident on the writing area of each of the photosensitive drums 30A to 30D in a state adjusted to a preset intensity.

  The photosensitive layers provided on the respective surfaces of the photosensitive drums 30A, 30B, 30C, and 30D are charged with a predetermined voltage by the charging means 32A, 32B, 32C, and 32D, so that charges are distributed at a constant density. ing. When each of the photoconductive drums 30A, 30B, 30C, and 30D is scanned as described above, the photosensitive layer at the portion where the laser beam is condensed has conductivity, and the potential is almost zero in that portion. It becomes. Thus, when the surface of each of the photoconductive drums 30A, 30B, 30C, and 30D is scanned by the laser beam while rotating in the direction indicated by the arrow in FIG. 1, the surface of each of the photoconductive drums 30A, 30B, 30C, and 30D Each is formed with an electrostatic latent image.

  When electrostatic latent images are formed on the surfaces of the photosensitive drums 30A, 30B, 30C, and 30D, the photosensitive drums 30A, 30B, 30C, and 30D are developed by the developing rollers of the developing units 33A, 33B, 33C, and 33D. Toner is supplied to the surface of 30D. The supplied toner is electrostatically attached to the electrostatic latent images on the photosensitive drums 30A, 30B, 30C, and 30D, and each electrostatic latent image is visualized by each color toner. Each visualized toner image is superimposed and transferred onto the surface of the intermediate transfer belt 40, and a full-color toner image is formed on the intermediate transfer belt 40. The formed full-color toner image is collectively transferred to the surface of the paper 61 fed from the paper feed tray 60 by the operation of the transfer charger 48, and the paper 61 on which the image is transferred is sent to the fixing means 50 and transferred. After the image is fixed, the paper is discharged onto the paper discharge tray 501a by the paper discharge roller pair 58.

  Here, the mounting configuration of the light-emitting element 1 which is a characteristic part of the present invention will be described. In the optical scanning device 100 described above, since a large number of lines are simultaneously written on the photosensitive drum 30, it is necessary to adjust the rotation of the light emitting element 1 so as to satisfy the predetermined pitch X1 on the photosensitive drum 30. In this rotation adjustment, the light emitting element 1 is rotated about the optical axis direction, thereby adjusting the light emitting point interval.

  FIG. 3 shows a two-beam light-emitting element 1. The light emitting element 1 is obtained by packaging a laser array 1a having two light emitting points P1 and P2. The package has a flange 1b, and the flange portion 1b is a straight line connecting the light emitting points P1 and P2. Two notches 1c are provided in a shape. By rotating and adjusting the light emitting element 1 in the direction of the arrow R shown in FIG. 3, the interval ΔP in the sub-scanning direction Q2 between the light emitting points P1 and P2 is adjusted so as to satisfy the predetermined pitch X1.

  As shown in FIG. 4, a mounting hole 13 for mounting the light emitting element 1 on the side wall 7 a, and a reference for positioning the light emitting element 1 in the optical axis direction when the light emitting element 1 is integrally formed with the mounting hole 13. A holding portion 11 formed integrally with the surface 7b and the side wall 7a, a circular recess 12, and a screw hole (not shown) are provided. The holding portion 11 has a hole for inserting the fixing screw 10 shown in FIG. 11a is drilled. The circular recess 12 has an outer diameter that allows a holding member 21 to be described later to rotate about the mounting hole 13, and the holding portion 11 is formed to be sufficiently thin compared to the thickness of the side wall 7a. 12 is formed to cover the shape. A gap slightly larger than the thickness of a brim portion 21 b of the holding member 21 described later is provided between the holding portion 11 and the circular concave portion 12, and the holding member 21 is provided between the holding portion 11 and the circular concave portion 12. It is configured to be able to move comfortably. The above-described holes 11a, screw holes (not shown), and mounting holes 13 are arranged so as to be positioned on a straight line parallel to the main scanning direction Q1.

  As shown in FIG. 5, the light-emitting element 1 has its flange portion 1b press-fitted and held in a holding hole 21a of a holding member 21 having a holding hole 21a, two flange portions 21b, and a hole 21c formed in each flange portion 21b. The light source unit 25 shown in FIG. 4 is configured by the light emitting element 1 and the holding member 21. The light emitting element 1 is held by the holding member 21 in such a manner that the light emitting side end surface (the back side surface in FIG. 5) of the flange portion 1 b protrudes from the holding member 21. It is comprised so that it may correspond to the level | step difference with the surface 7b. At the time of press-fitting, press-fitting is performed so that the angle formed by the straight line connecting the centers of the holes 21c and the straight line connecting the notches 1c is 6 to 7 ° so that the predetermined pitch X1 is 20 μm. Do. In this embodiment, the angle is 6 to 7 °, but this angle is changed depending on the set value of the predetermined pitch X1.

  Next, a procedure for adjusting the attachment of the light source unit 25 including the light emitting element 1 to the side wall 7a will be described. First, the light source unit 25 is inserted into the mounting hole 13. Next, the light source unit 25 is rotated around the optical axis as shown in FIG. 6, and the flanges 21b are inserted into the gaps between the holding parts 11 and the circular recesses 12 as shown in FIG. At this time, each collar portion 21b is pressed by each holding portion 11, and the light source unit 25 is fixed in the optical axis direction with the flange portion 1b in contact with the reference surface 7b. Then, as shown in FIG. 8, the light source unit 25 is chucked by the rotating jig J, and the light source unit 25 is rotated around the optical axis to adjust the beam interval. After adjustment, the light source unit 25 is fixed as shown in FIG. The holding member 21 is fixed to the side wall 7a by the screw 10. At the time of fixing, the thickness of the holding portion 11 is sufficiently thin with respect to the thickness of the side wall 7a, so that the rigidity is low, so that deformation of the side wall 7a at the time of fixing is suppressed, and the side wall 7a is deformed at the time of fixing, thereby changing the optical axis. Tilt is prevented.

  With the above-described configuration, the light source unit 25 is positioned by contact with the reference surface 7b by the holding portion 11, so that the light emitting element 1 or the rotation jig itself is pushed against the side wall 7a by the rotation jig as shown in FIG. Since the side wall 7a is not subjected to unnecessary external force without being hit, it is not elastically deformed, and the occurrence of the problem that the elastic deformation of the side wall 7a affects the adjustment of the beam interval during and after the beam interval adjustment is prevented. can do.

  With the above-described configuration, it is possible to prevent the position of the scanning light beam from changing due to the tilt of the side wall of the optical housing. Therefore, if the optical writing system is used, the stability of the scanning line can be obtained, so that a good image quality can be obtained. . In addition, since the function of the jig for holding the light emitting element can be limited to only rotation adjustment, the structure of the jig can be simplified and the cost can be reduced.

  FIG. 11 shows a modification of the above embodiment of the present invention. In this modification, instead of the holding member 21, a holding member 22 having two flange portions 22 a that are bent so as to be folded is used, and a gap between the holding portion 11 and the circular recess 12 is formed as a flange portion 22 a. This is different from the above embodiment in that it is formed to be smaller than the thickness (the thickness of the base and the free end). Each flange portion 22a is formed with two holes through which the fixing screw 10 is inserted. According to this modification, when the holding member 22 is submerged between the holding portion 11 and the circular concave portion 12, it has a function of applying pressure to each holding portion 11 by each flange portion 22a as shown in FIG. Therefore, the light emitting element 1 can be reliably pressed against the reference surface 7b as compared with the above embodiment, and the positioning accuracy can be improved.

  FIG. 13 shows another modification of the above embodiment. In this example, there are two flange portions 23a that are bent and two protrusion portions 23b that are formed separately from each flange portion 23a, and the fixing screw 10 is inserted into each protrusion portion 23b. A holding member 23 having a mounting portion 23d for mounting the hole 23c and the rotating jig J is used. In this case, the holding part 11 has a shape as shown in FIG. By adopting this configuration, the light source unit 25 can be fixed to the side wall 7a without using the bent flange portion 23a, so that the fluctuation of the beam interval at the time of fixing can be further reduced.

  FIG. 15 shows still another modification of the above embodiment. In this example, there are two flange portions 24a that are bent and two protrusion portions 24b that are bent separately from each flange portion 24a, and the fixing screw 10 is inserted into each protrusion 24b. The holding member 24 in which the hole 24c and the connecting portion 24d with the rotating jig are formed is used. With this configuration, the beam width can be adjusted with a simpler rotating jig.

  Although the number of laser beams is 2 in the above embodiment and each modification, it may be 3 or more, and the number of holding portions 11 and the corresponding flange portions 21b, 22a, 23a, 24a is 2. May be 3 or more. Moreover, in the said embodiment and each modification, although the holding part 11 was integrally formed with the side wall 7a, as shown in FIG. 16, it is good also as a structure which fixes the plate member 15 which has a function of a holding part to the side wall 7a. Further, in the present embodiment and each modification, the light emitting element 1 is fixed to the holding members 21, 22, 23, and 24 by press-fitting, but instead of press-fitting, the light-emitting element 1 is fixed by a method such as adhesion, brazing, or welding. May be. Furthermore, in this embodiment and each modification, the light source unit 25 is fixed to the side wall 7a by the fixing screw 10, but instead, it may be fixed by a method such as adhesion, brazing, or welding.

1 Light Emitting Element 7 Housing (Optical Housing)
7b Reference surface 7c, 7d, 7e Mounting hole 11 Holding portion 13 Mounting hole 21, 22, 23, 24 Holding member 21b, 22a, 23a, 24a Hook portion 23d Mounting portion 100 Optical scanning device 500 Image forming device P1, P2 Light emitting point (Laser beam)

Japanese Patent Laid-Open No. 10-10447 JP-A-10-319338 Japanese Patent Laid-Open No. 11-72728

Claims (8)

In a light emitting element adjustment fixing structure in which a light emitting element having a plurality of light emitting points is rotated around an optical axis of the light emitting point to adjust a distance between the light emitting points and fix the light emitting element to a housing.
The light emitting element is held by a holding member, and the holding member is held so that the housing can rotate freely in a state where the light emitting element is in contact with the reference surface and a mounting hole having a reference surface to which the light emitting element is attached. An adjustment fixing structure for a light emitting element, wherein the light emitting element is fixed to the housing after the light emitting element is rotationally adjusted in a state where the holding member is held by the holding part. In the adjustment fixing structure of the light emitting element according to claim 1,
The structure of adjusting and fixing a light-emitting element, wherein the holding portion has a thickness sufficiently smaller than a thickness of the housing. In the adjustment fixing structure of the light emitting element according to claim 1 or 2,
The holding structure of the light emitting element is characterized in that the holding member has a flange portion formed by bending. In the adjustment fixing structure of the light emitting element as described in any one of Claims 1 thru | or 3,
The light-emitting element adjustment fixing structure, wherein the holding member has an attachment portion to which a rotating jig used for adjustment is attached. In the adjustment fixing structure of the light emitting element according to any one of claims 1 to 4,
The light-emitting element adjusting and fixing structure, wherein the holding member holds the light-emitting element by press-fitting the light-emitting element. In the adjustment fixing structure of the light emitting element according to claim 5,
The light-emitting element adjusting and fixing structure, wherein the light-emitting element is press-fitted into the holding member while being inclined at a predetermined angle according to an image pitch.   An optical scanning device comprising the light emitting element adjustment fixing structure according to claim 1.   An image forming apparatus comprising the optical scanning device according to claim 7.

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