JP2009139803A - Light source device for image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact light source device for an image forming apparatus, in which optical element holders are disposed with a small pitch on a frame. <P>SOLUTION: The light source device 1 for image forming apparatus has a plurality of laser element holders 14a and 14b which are provided with: a flange part 19 which holds a laser element 13 and is perpendicular to laser light; and a plurality of arm parts 20a and 20b which extend from the flange part 19 to the side face of the optical element holder 16, and are connected to the optical element holder 16 which holds the optical element 15, wherein the arm parts 20a and 20b are provided being shifted to the position in a subscanning direction at least at the side of the optical element holder 16 so that the arm parts 20a and 20b of one laser element holder are not superimposed with the arm parts 20a and 20b of adjacent laser element holders 14a and 14b in a main scanning direction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a light source device for an image forming apparatus.

  In Patent Document 1, a base (laser element holder) that holds a semiconductor laser element and a lens barrel (optical element holder) that holds a lens (optical element) are bonded to each other by a groove provided on a bonding surface. An optical device is described. In this case, it is important to maintain the positional relationship between the base and the lens barrel until the adhesive is cured.

  Patent Document 2 describes an optical device in which a lens barrel is bonded to a holder with an ultraviolet curable resin (photo-curing adhesive) having a short curing time, and a base is screwed to the holder. However, since a light beam cannot be applied to the joint surface where the light-shielding members are in close contact with each other, it is not possible to simply apply the photocurable adhesive to the joint between the base and the lens barrel of Patent Document 1.

  Since a light-curing adhesive that joins the base that holds the laser element and the lens barrel that holds the lens is arranged in a column shape and a gap is provided on the joint surface between the base and the lens barrel, an optical path can be secured. The base and the lens barrel can be joined with a photo-curing adhesive. However, since the photocurable adhesive contracts as it hardens, the distance between the laser element and the lens is shortened. For example, if the lens is a collimator lens that converts laser light into parallel light, the distance between the laser element and the lens is shortened, so that the laser light that has passed through the lens is slightly diffused, resulting in poor optical performance. A problem occurs.

  At the time of assembling the light source device, the positions of the base and the lens barrel are determined while checking the image of the laser beam, and the light curable adhesive is cured by irradiating the light curable adhesive with light. For this reason, it is difficult to add extra photocurable adhesive to the extent that it shrinks. Even if the shrinkage of the cured resin at the time of assembly can be corrected, the photo-curing adhesive gradually expands due to moisture absorption, so that the distance between the laser element and the lens increases with time and the optical performance deteriorates. .

Therefore, as shown in FIG. 15, the laser element holder 32 that holds the laser element 31 is formed in a U-shape extending to the side of the optical element holder 34 that holds the lens 33, and the optical element holder 34 side is formed. By mounting the photocurable adhesive 35 on the side and joining the base, the expansion and contraction of the photocurable adhesive 35 can be prevented from moving the laser element 31 in the optical axis direction. However, since the laser element holder 32 extends to the side of the optical element holder 34, the distance between the optical element holders 34 is increased when the laser element holder 32 is arranged on the common frame 36, and the light source device is increased in size. is there.
Japanese Patent Laid-Open No. 5-136852 Japanese Patent Application Laid-Open No. 5-273383

  In view of the above problems, it is an object of the present invention to provide a small light source device for an image forming apparatus in which optical element holders are arranged on a frame at a small interval.

  In order to solve the above problems, a light source device for an image forming apparatus according to the present invention holds a plurality of laser elements that emit laser light, a plurality of optical elements that shape the laser light, and the optical elements one by one. The plurality of optical element holders and the laser elements are held one by one, the flange portion of the laser element is perpendicular to the laser beam, and the flange portion is extended to the side surface of the optical element holder and joined to the optical element holder. A plurality of laser element holders having a plurality of arm portions, and a frame in which the optical element holders are arranged in a main scanning direction perpendicular to the laser light, and the arm portions include at least the optical element The adjacent arm portions on the side of the element holder so as not to overlap the adjacent arm portions of the adjacent laser element holder in the main scanning direction; And what is provided by shifting the position in the vertical sub-scanning direction to serial main scanning direction and the optical axis.

  According to this configuration, by arranging the arm portions alternately, the interval between the adjacent optical element holders can be shortened without bringing the arm portions into contact with each other, and the light source device can be miniaturized.

  In the light source device for an image forming apparatus according to the present invention, the laser element holders may be arranged in an arc shape so that the optical axes intersect at one point.

  According to this configuration, the downstream components can be efficiently arranged by collecting the laser beams emitted from the respective laser elements at one point.

  In the light source device for an image forming apparatus according to the present invention, the laser element holder may be made of a metal material.

  According to this configuration, the laser element holder can be used as a heat radiating plate or an electric circuit of the laser element.

  In the light source device for an image forming apparatus according to the present invention, the arm portion may be joined to the optical element holder with a gap by a photo-curing adhesive placed on the optical element holder.

  According to this configuration, the laser element holder can be bonded to the optical element holder in a state where the laser element is accurately positioned with respect to the optical element.

  In the light source device for an image forming apparatus according to the present invention, the arm portion may be at least partially covered with an insulating material.

  According to this configuration, even if the laser element holder is conductive and is used as an electric circuit, the portion where the arms of the adjacent laser element holders are closest to each other is covered with the insulating material, so that Short circuit can be prevented.

  The laser element holder is provided with an arm that extends in the sub-scanning direction from the adjacent laser element holder and extends to the side surface of the optical element holder, so that the laser element can be accurately positioned and fixed with respect to the optical element. Since the element holders can be arranged at a small interval, a small light source device for an image forming apparatus can be provided.

Embodiments of the present invention will now be described with reference to the drawings.
FIG. 1 shows a tandem scanning optical device 2 for an image forming apparatus provided with a light source device 1 of the present invention. In the light source device 1, a total of four types of laser units 4a and 4b are arranged on the frame 3, and the laser beams emitted from the laser units 4a and 4b are superimposed by the half mirror 5, and the reflecting mirror 6 and The polarizer 8 is irradiated through the cylindrical lens 7. The polarizer 8 changes the direction of reflection so as to scan the laser beam. The laser units 4 a and 4 b are arranged on the frame 3 side by side in the main scanning direction orthogonal to the optical axis of the laser light within the plane in which the laser light is scanned by the polarizer 8.

  The scanning optical device 2 irradiates the photoconductor 11Y with the laser light emitted from the light source device 1 via the first scanning lens 9 and the second scanning lens, and further performs photosensitivity via the mirrors 12M, 12C, and 12K. The bodies 11M, 11C, and 11K are irradiated to form electrostatic latent images on the surfaces of the photoreceptors 11Y, 11M, 11C, and 11K, respectively.

  FIG. 2 shows details of the light source device 1. The laser unit 4a includes a metal laser element holder 14a that holds a laser diode (laser element) 13 that emits laser light, and a collimator lens (optical element) 15 that shapes the laser light emitted by the laser diode 13 into parallel rays. It comprises an optical element holder 16 made of a light-shielding resin to be held, and a laser element holder 14 a is joined to the optical element holder 16 by a photocurable adhesive 17. Each of the laser units 4 a is joined to the frame 3 by a photocurable adhesive 18.

  Further, as shown in detail in FIG. 3, the laser element holder 14 a has a plate shape perpendicular to the optical axis of the laser diode 13, a flange portion 19 that holds the laser diode 13, and an optical axis from the end of the flange portion 19. And a plurality of arm portions 20a that are joined to the optical element holder 16 with a gap therebetween by a photo-curing adhesive 17 that extends to the side surface of the optical element holder 16 and that has a tip placed on the optical element holder 16. Become. The laser element holder 14a also functions as a heat radiating plate that efficiently dissipates heat generated by the laser diode 13 into the surrounding air by providing a gap between the laser element holder 14a and the optical element holder 16.

  As shown in FIG. 4, the arm portion 20a of the laser element holder 14a is adjacent to the arm portion 20b of the adjacent laser element holder 14b and the sub-scanning direction (height direction) orthogonal to the main scanning direction and the optical axis of the laser beam. ) Are shifted so that they do not overlap when viewed in the main scanning direction. Specifically, the laser unit 4a having the laser element holder 14a extending from the upper and lower ends of the side edge of the flange portion 19 and the two arm portions 20b from the vicinity of the center of the side edge of the flange portion 19, respectively. Are alternately arranged with laser units 4b having laser element holders 14b extending. The laser unit 4a and the laser unit 4b are arranged so that the arm part 20a of the laser element holder 14a overlaps the adjacent arm part 20b of the laser element holder 14b in the sub-scanning direction.

  When assembling the laser units 4a and 4b, the laser element holders 14a and 14b on which the photocurable adhesive 17 is mounted and the laser diode 13 is fixed are placed at predetermined positions on the side surfaces of the optical element holder 16, and the arm portions 20a and 20b are attached. The tip is pushed and expanded within an elastic range so that the arms 20 a and 20 b do not come into contact with the photocurable adhesive 17 and are arranged at a predetermined position with respect to the optical element holder 16. In this state, the arm portions 20a and 20b are restored, and the arm portions 20a and 20b are brought into contact with the tip of the photocurable adhesive 17 placed on the optical element holder 16, so that the optical element holder 16 and the arm portions 20a and 20b These are cross-linked by the photocurable resin 17. Then, power is supplied to the laser diode 13 to generate laser light, and while monitoring the laser light emitted from the collimator lens 15, the laser element holders 14 a and 14 b can be maintained within a range in which the crosslinked state of the photocurable resin 17 can be maintained. The laser element holders 14a and 14b are held at positions where the laser light emitted from the collimator lens 15 becomes a strict parallel light beam. In this state, the laser element holders 14 a and 14 b are bonded to the optical element holder 16 by irradiating ultraviolet rays from the gap between the optical element holder 16 and the arm portions 20 a and 20 b to cure the photocurable adhesive 17. To do.

  By assembling in the above procedure, the laser units 4a and 4b have the optimum positional relationship between the laser diode 13 and the collimator lens 15 and can emit precise parallel rays. Similarly, the laser unit is positioned with respect to the downstream member below the half mirror 5 and fixed to the frame 3 by the photo-curing adhesive 18, whereby the high-performance light source device 1 can be assembled.

  Further, by providing the arm portions 20a and 20b of the laser element holders 14a and 14b alternately, the interval between the laser units 4a and 4b can be shortened in the main scanning direction, and the light source device 1 can be reduced in size.

  If the processing accuracy of the collimator lens 15 and the optical element holder 16 is high, the frame 3 and the optical element holder 16 may be integrally formed as in the light source device 1 of the second embodiment of the present invention shown in FIG. . In the following description of the present embodiment, the same components as those described above are denoted by the same reference numerals, and redundant descriptions are omitted.

  FIG. 6 shows the shape of the laser element holder 14 of the light source device 1 according to the third embodiment of the present invention. The laser element holder 14 of this embodiment is sub-scanned slightly larger than the width of the arm part 20a extending in the optical axis direction from one end of the side of the flange part 19 and the arm part 20a of the laser element holder 14 adjacent from the other end. And an arm portion 20b that is offset in the direction and extends in the optical axis direction. As shown in the figure, the arm portions 20a and 20b of the adjacent laser element holders 14 are alternately extended, but these laser element holders 14 have the same shape and are arranged upside down. Only. In this embodiment, since the shape of the laser element holder 14 is only one type, the component cost is low.

  Further, like the laser element holder 14 of the light source device 1 according to the fourth embodiment of the present invention shown in FIG. 7, the arm portion 20b on one side of the flange portion 19 is provided near the center, and the arm on the other side is provided. The shape of the laser element holder 14 can also be unified by providing the portions 20a at the upper and lower ends.

  FIG. 8 shows a view of the light source device 1 according to the fifth embodiment of the present invention viewed from the downstream side of the laser beam. The optical element holder 16 of the present embodiment has a T-shaped projection shape in the optical axis direction, and the laser element holder 14 extends to both end portions of the T-shaped horizontal bar of the optical element holder 16. A pair of arm portions 20 are provided. The optical element holder 16 is disposed on the frame 3 so as to be upside down with respect to the adjacent optical element holder 16. In the present embodiment, the arm portion 20 of the laser element holder 14 of each laser unit 4 is arranged closer to the center of the adjacent laser unit 4 than the arm portion 20 of the laser element holder 14 of the adjacent laser unit 4.

  Similarly, as in the light source device 1 of the sixth embodiment of the present invention shown in FIG. 9 and the light source device 1 of the seventh embodiment of the present invention shown in FIG. By disposing the arm portion 20 of the element holder 14 in the sub-scanning direction so as not to overlap the arm portion 20 of the laser element holder 14 of the adjacent adjacent laser unit 4 in the main scanning direction, a gap between the laser units 4 is provided. Can be reduced.

  Further, FIG. 11 shows a laser unit 4a of the light source device 1 according to the eighth embodiment of the present invention. In the present embodiment, the outer side of the arm portion 21 of the laser element holder 14a on the downstream side in the optical axis direction is covered with an insulating tape (insulating material) 21 made of, for example, a fluororesin. As a result, even when the arm portion 20a is deformed, or when the laser element holder 14a needs to be greatly inclined when the laser unit 4a is assembled, the arm portion 20b of the laser unit 4b adjacent to the arm portion 20a (non- Do not touch directly. For this reason, even when the metal laser element holder 14a is used as an electric circuit for supplying power to the laser diode 13, it is not short-circuited with the electric circuit of the laser diode 13 of the adjacent laser unit 4b.

  Furthermore, in FIG. 12, the shape of the laser element holder 14a of the light source device 1 of 9th Embodiment of this invention is shown. In the present embodiment, the laser element holder 14a has a connection portion 22 that extends in the optical axis direction from the sides on both sides, and further extends on both sides in the sub-scanning direction. A step is formed so as to extend from both ends in the sub-scanning direction in the main scanning direction, and is formed on the side surface of the optical element holder 16 so as to extend in the optical axis direction.

  As shown in the present embodiment, in the present invention, the laser element holder 14a may have only the arm portion 20a extending in the optical axis direction on the outermost side in the main scanning direction. Then, for example, like the laser element holder 14 of the light source device 1 of the tenth embodiment of the present invention shown in FIG. 13, the arm portions 20 a and 20 b are separated from the adjacent arm portions 20 a and 20 b of the adjacent laser element holder 14. By shifting the position in the sub-scanning direction so that at least a portion extending to the side of the optical element holder 16 does not overlap in the main scanning direction, the laser units 4 can be arranged at a small interval.

  FIG. 14 shows a light source device 1 according to an eleventh embodiment of the present invention. In the present embodiment, the optical element holder 16 is arranged on the frame 3 so as to draw an arc so that the laser beams emitted from the laser units 4 a and 4 b intersect at one point in the polarizer 8. Here, the main scanning direction referred to in the present invention is a direction perpendicular to the optical axis of each laser beam in each of the laser units 4a and 4b, and is a direction in which the laser beam is scanned. Thus, the directions of the laser units 4a and 4b may be different.

  In the present embodiment, the laser units 4a and 4b are arranged in an arc shape so that the laser beams of the laser units 4a and 4b are collected at one central point of the arc, so that a special laser beam such as the half mirror 5 is superimposed. Even without such a member, the downstream configuration can be integrated into one and simplified.

1 is a schematic view of a scanning optical device having a light source device according to a first embodiment of the present invention. The side view of the light source device of FIG. The perspective view of the laser unit of the light source device of FIG. The fragmentary perspective view of the light source device of FIG. The side view of the light source device of 2nd Embodiment of this invention. The perspective view of the laser element holder of the light source device of 3rd Embodiment of this invention. The perspective view of the laser element holder of the light source device of 4th Embodiment of this invention. The front view of the light source device of 5th Embodiment of this invention. The front view of the light source device of 6th Embodiment of this invention. The front view of the light source device of 7th Embodiment of this invention. The perspective view of the laser unit of the light source device of 8th Embodiment of this invention. The perspective view of the laser element holder of the light source device of 9th Embodiment of this invention. The perspective view of the laser element holder of the light source device of 10th Embodiment of this invention. The top view of the light source device of 11th Embodiment of this invention. The top view of the light source device by a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Light source device 2 ... Scanning optical apparatus 3 ... Frame 4, 4a, 4b ... Laser unit 13 ... Laser diode (laser element)
14, 14a, 14b ... Laser element holder 15 ... Collimator lens (optical member)
DESCRIPTION OF SYMBOLS 16 ... Optical member holder 17 ... Photocurable adhesive 18 ... Photocurable adhesive 19 ... Flange part 20, 20a, 20b ... Arm part 21 ... Insulating tape (insulating material)
22 ... Connection part

Claims (5)

A plurality of laser elements emitting laser light;
A plurality of optical elements for shaping the laser beam;
A plurality of optical element holders for holding the optical elements one by one;
Holding the laser elements one by one, a flange portion perpendicular to the laser light of the laser element and a plurality of arm portions extending from the flange portion to a side surface of the optical element holder and joined to the optical element holder A plurality of laser element holders comprising:
The optical element holder has a frame arranged in a main scanning direction perpendicular to the laser beam,
The arm portion is adjacent to the adjacent arm portion of the adjacent laser element holder at least on the side of the optical element holder in the main scanning direction so as not to overlap the adjacent main arm direction and the main scanning direction. A light source device for an image forming apparatus, wherein the light source device is provided with a position shifted in a sub-scanning direction perpendicular to the optical axis.   The light source device for an image forming apparatus according to claim 1, wherein the laser element holders are arranged in an arc shape so that the optical axes intersect at one point.   The light source device for an image forming apparatus according to claim 1, wherein the laser element holder is made of a metal material.   4. The image formation according to claim 1, wherein the arm portion is joined to the optical element holder with a gap by a photo-curing adhesive placed on the optical element holder. 5. Light source device for apparatus.   5. The light source device for an image forming apparatus according to claim 1, wherein the arm portion is at least partially covered with an insulating material.

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