JP2009139464A - Light source device for image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light source device for an image forming apparatus capable of precisely regulating a positional relationship of a laser device and an optical element by joining a holding member for holding the optical element with a photocuring resin. <P>SOLUTION: The light source device attaches a laser device holding member 9 for holding the laser device 1 emitting laser light, and an optical element holding member 10 for holding the optical element 2 shaping the laser light to a laser fixing part 13 and an optical element fixing part 14 of a holder 11 respectively, with a gap on the same side of an optical axis direction of the laser light by means of a plurality of columnar built-up photocuring resins 12. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a light source device for an image forming apparatus such as a laser beam printer.

  In Patent Document 1, a base (laser element holding member) for holding a semiconductor laser element and a lens barrel (optical element holding member) for holding a lens (optical element) are provided with a groove on the joint surface and an adhesive. A bonded 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 adhesive (photo-curing resin) having a short curing time, and a base is screwed to the holder. However, since light cannot be applied to the joint surface where the light-shielding members are in close contact with each other, the photo-curing resin cannot be simply applied to the joint between the base and the lens barrel of Patent Document 1.

  As shown in FIG. 15, a photo-curing resin 35 that joins a base 32 that holds a laser element 31 and a lens barrel 34 that holds a lens 33 is arranged in a column shape, and a joint surface between the base 32 and the lens barrel 34. Since a light path can be secured if a gap is provided, the base 32 and the lens barrel 34 can be bonded to each other by the photo-curing resin 35. However, as shown in FIG. 16, since the photo-curing resin 35 contracts with curing, the distance between the laser element 31 and the lens 33 is shortened. For example, if the lens 33 is a collimator lens that converts laser light into parallel rays, the distance between the laser element 31 and the lens 33 is shortened, so that the laser light that has passed through the lens 33 is slightly diffused. There is a problem that performance decreases.

At the time of assembling the light source device, the positions of the base 32 and the lens barrel 34 are determined while confirming the image of the laser beam, and the light curable resin 35 is irradiated with light to cure the light curable resin 35. For this reason, it is difficult to provide extra photocurable resin 35 as much as it shrinks. Even if the shrinkage of the cured resin 35 at the time of assembly can be corrected, the photocurable resin 35 gradually expands due to moisture absorption, so that the distance between the laser element 31 and the lens 33 increases with time, and the optical performance is improved. There is a problem of lowering.
Japanese Patent Laid-Open No. 5-136852 Japanese Patent Application Laid-Open No. 5-273383

  In view of the above problems, the present invention provides a light source device for an image forming apparatus capable of joining a holding member for holding an optical element with a photo-curing resin and capable of precisely adjusting the positional relationship between the laser element and the optical element. The task is to do.

  In order to solve the above problems, a light source device for an image forming apparatus according to the present invention includes a laser element holding member that holds a laser element that emits laser light, and an optical element holding member that holds an optical element that shapes the laser light. A laser element fixing part for attaching the laser element holding member, an optical element fixing part for attaching the optical element holding member, and a holder comprising a base part for holding the laser element fixing part and the optical element fixing part. The laser element holding member and the optical element holding member are respectively arranged in the optical axis direction of the laser beam by a photo-curing resin arranged at a plurality of positions with respect to the laser element fixing portion and the optical element fixing portion, respectively. It shall be installed on the same side with a gap.

  According to this configuration, the shrinkage accompanying the curing of the photocurable resin and the elongation due to the aging of the photocurable resin move the laser element holding member and the optical element holding member in the same direction. For this reason, the positional relationship between the laser element and the optical element does not change, and the positional accuracy when adjusted at the time of assembly can be continuously maintained after the photo-curing resin is cured and thereafter used.

  In the light source device for an image forming apparatus of the present invention, the holder may be formed integrally with the base portion and the optical element fixing portion.

  According to this configuration, the number of parts is small and the dimensional accuracy is high.

  In the light source device for an image forming apparatus according to the present invention, the optical element fixing portion has an attachment surface orthogonal to the optical axis of the laser light, and the optical element holding member is attached to the attachment surface. Good.

  According to this configuration, since the movement of the laser element and the optical element due to the curing of the photo-curing resin is in the optical axis direction, the laser element and the optical element are not misaligned with respect to the holder.

  In the light source device for an image forming apparatus according to the present invention, the optical element may have a function of a collimator lens and a cylindrical lens.

  According to this configuration, the collimator lens that converts the laser light into parallel rays and the cylindrical lens that condenses the parallel rays into a linear shape are integrated, so that the number of components to be positioned is small.

  In the light source device for an image forming apparatus of the present invention, the photocurable resin may have a glass transition temperature of 110 ° C. or lower.

  According to this configuration, the laser element holding member and the optical element holding member are hardly peeled off, and the secular change is small.

  In the light source device for an image forming apparatus according to the present invention, the gap between the laser element holding member and the laser element fixing portion, and the gap between the optical element holding member and the optical element fixing portion are respectively 0. The photocuring resin may have a viscosity at 25 ° C. of 6000 mPa · s or more and 30000 mPa · s or less when uncured.

  According to this configuration, since the viscosity is high, the photocurable resin can be arranged in a column shape at the time of assembly, and since the viscosity is not too high, the supply amount of the photocurable resin can be appropriately controlled at the time of assembly.

  In the light source device for an image forming apparatus according to the present invention, the photocurable resin may be an ultraviolet curable resin.

  According to this configuration, positioning is performed while visually observing under visible light, and the photo-curing resin can be cured by ultraviolet rays, so that assembly is easy.

  In the light source device for an image forming apparatus according to the present invention, the distance from the center of the photocurable resin to the end of the optical element holding member is five times the gap between the optical element holding member and the optical element fixing portion. It may be the following.

  According to this configuration, it is possible to irradiate a light beam sufficient to cure the photocurable resin from the gap between the optical element holding member and the optical element fixing portion.

  In the light source device for an image forming apparatus of the present invention, a recess for receiving the photocurable resin is provided in at least one of the laser element holding member, the laser element fixing portion, the optical element holding member, and the optical element fixing portion. It may be provided.

  According to this configuration, the depression serves as a mark for the position where the photo-curing resin is to be placed, and can be held in a columnar shape by preventing dripping due to the surface tension of the photo-curing resin. Moreover, since a hollow increases a contact area with cured resin, it can raise adhesive strength.

  Further, in the light source device for an image forming apparatus of the present invention, a protrusion embedded in at least one of the laser element holding member, the laser element fixing portion, the optical element holding member, and the optical element fixing portion. May be provided.

  According to this configuration, the protrusion serves as a mark of the position where the photocurable resin is to be placed, and the protrusion holds the photocurable resin by placing the photocurable resin around the protrusion. it can. As a result, the gap between the laser element holding member and the laser element fixing portion and the gap between the optical element holding member and the optical element fixing portion, that is, the optical path of the light beam for curing the photocurable resin can be increased. It is surely cured.

  In the light source device for an image forming apparatus according to the present invention, the photocurable resin is disposed in at least one of the laser element holding member, the laser element fixing portion, the optical element holding member, and the optical element fixing portion. A small hole may be provided at the position.

  According to this configuration, the small hole serves as a mark for the position where the cured resin is to be placed, and can be used as an optical path for irradiating a light beam for curing the photocurable resin. Alternatively, a photo-curing resin can be injected from the small holes and arranged in a columnar shape.

  According to the present invention, the laser element holding member and the optical element holding member are attached to the holder with a gap on the same side in the optical axis direction of the laser beam by the photo-curing resin arranged at a plurality of locations. The expansion and contraction of the photo-curing resin moves the laser element holding member and the optical element holding member in the same direction. For this reason, the positional relationship between the laser element and the optical element does not change, and the positional accuracy when adjusted at the time of assembly can be continuously maintained after the photo-curing resin is cured and thereafter used.

Embodiments of the present invention will now be described with reference to the drawings.
FIG. 1 shows a configuration of a print head of a laser beam printer (image forming apparatus). The print head includes a laser diode (laser element) 1 that emits a laser beam, a collimator lens (optical element) 2 that shapes the laser beam emitted from the laser diode 1 into a parallel beam, and reflects the laser beam in the main scanning direction. , A deflector 3 that deflects the laser beam, a first scanning lens 4 and a second scanning lens 5 that focus the laser beam, a cover glass 6, and a photoconductor 7 on which an electrostatic latent image is formed by the laser beam. And have.

  FIG. 2 is an exploded perspective view of the light source device 8 according to the first embodiment of the present invention including the laser diode 1 and the collimator lens 2, and FIGS. 3 and 4 are a side view and a plan view of the light source device 8, respectively. The light source device 8 includes an ultraviolet curable resin (light) in which a laser element holding member 9 for holding the laser diode 1 and an optical element holding member 10 for holding the collimator lens 2 are arranged in a columnar shape with respect to the holder 11. (Hardened resin) 12 is attached.

  The holder 11 has a laser element fixing portion 13 constituting an attachment surface 13a orthogonal to the optical axis of the laser beam to which the laser element holding member 9 is attached, and an attachment orthogonal to the optical axis of the laser light to which the optical element holding member 10 is attached. The optical element fixing part 14 which comprises the surface 14a, and the base part 15 holding the laser element fixing part 13 and the optical element fixing part 14 are comprised. Each of the laser element fixing part 13 and the optical element fixing part 14 has an opening serving as an optical path for laser light.

  The ultraviolet curable resin 12 is arranged on the same side in the optical axis direction of the laser element fixing portion 13 and the optical element fixing portion 14 (on the upstream side of the laser beam), and is arranged in a columnar shape with equal heights at a plurality of locations. The member 9 and the optical element holding member 10 are held with an equal gap between the laser element fixing portion 13 and the optical element fixing portion 14, respectively.

  In assembling the light source device 8, first, the ultraviolet curable resin 12 is placed at a plurality of locations of the laser element fixing portion 13 and the optical element fixing portion 14. Then, the laser element holding member 9 to which the laser diode 1 is fixed and the optical element holding member 10 to which the collimator lens 2 is fixed are placed in contact with the laser element fixing portion 13 and the optical element fixing portion 14 with a gap therebetween. It arrange | positions in contact with the front-end | tip of the ultraviolet curable resin 12 currently made. Thereby, a plurality of columns of the ultraviolet curable resin 12 are formed between the laser element holding member 9 and the laser element fixing portion 13 and between the optical element holding member 10 and the optical element fixing portion 14, respectively. Then, laser light is generated by the laser diode 1 and the positions of the laser element holding member 9 and the optical element holding member 10 are finely adjusted while confirming the laser light emitted from the position. When the optical axes of the laser diode 1 and the collimator lens 2 are aligned, and the distance between the laser diode 1 and the collimator lens 2 is the designed distance, the parallel light beam is emitted from the collimator lens 2, so that the parallel light beam is confirmed. While the laser element holding member 9 and the optical element holding member 10 are held in such a state, the column of the ultraviolet curable resin 12 is irradiated with ultraviolet rays and cured.

  The ultraviolet curable resin 12 contracts at the time of curing and moves the laser element holding member 9 and the optical element holding member 10 in the optical axis direction. However, since the lengths thereof are substantially the same, the contraction amounts are substantially equal. Further, since the laser element holding member 9 and the optical element holding member 10 are disposed on the same side with respect to the laser element fixing part 13 and the optical element fixing part 14, the laser element holding member 9 and the optical element holding member 9 are The direction in which the optical element holding member 10 moves is the same. Therefore, the laser element holding member 9 and the optical element holding member 10 are moved by the same distance in the optical axis direction by the same distance due to the shrinkage of the ultraviolet curable resin 12, and the distance between the laser diode 1 and the collimator lens 2 is kept constant. Further, the ultraviolet curable resin 12 expands due to moisture absorption when used for a long period of time, but the movement of the laser element holding member 9 and the optical element holding member 10 due to such a change with time also occurs substantially equally, so the laser diode 1 and the collimator The distance to the lens 2 is unchanged. As described above, the light source device 8 can maintain the positional relationship between the laser diode 1 and the collimator lens 2 adjusted at the time of assembly regardless of the expansion / contraction of the ultraviolet curable resin 12 and accurately emit parallel laser light. Can do.

  5 to 7 show a light source device 8a according to a second embodiment of the present invention. In the following description, the same components as those described above are denoted by the same reference numerals, and redundant descriptions are omitted. In the light source device 8a of the present embodiment, the laser element holding member 9 and the optical element holding member 10 are respectively provided with mounting surfaces 13a and 14a as the downstream surfaces of the laser light of the laser element fixing portion 13 and the optical element fixing portion 14, respectively. These are mounted with a space between the mounting surfaces 13a and 14a by the ultraviolet curable resin 12 arranged in a columnar shape at a plurality of locations.

  In the present embodiment, contrary to the first embodiment, when the ultraviolet curable resin 12 contracts, the laser diode 1 and the collimator lens 2 move to the laser diode 1 side (upstream side of the laser light) in the optical axis direction, and the ultraviolet light When the cured resin 12 expands, the laser diode 1 and the collimator lens 2 move to the collimator lens 2 side (downstream side of the laser light) in the optical axis direction. It goes without saying that the positional relationship between the laser diode 1 and the collimator lens 2 is unchanged even with this configuration.

  In addition, it is preferable that the viscosity at normal temperature (25 degreeC) at the time of uncuring is 6000 mPa * s or more so that the ultraviolet curable resin 12 may be piled up in a column shape without dripping. Moreover, since it will become difficult to supply a predetermined amount correctly when the viscosity is too high, it is preferable that it is 30000 mPa * s or less.

  Further, the height of the ultraviolet curable resin 12 (the gap between the laser element holding member 9 and the optical element holding member 10 and the laser element fixing portion 13 and the optical element fixing portion 14) is an ultraviolet light path for curing the ultraviolet curable resin 12. In order to ensure, it is preferable to set it as 0.1 mm or more, and it is preferable to set it as 1 mm or less in order to maintain a columnar bridge | crosslinking state before hardening. A photo-curing resin that is cured by light having a wavelength other than ultraviolet light may be used. However, in order to perform assembly work under visible light, it is preferable to use an ultraviolet-curing resin that is cured by ultraviolet light.

  Further, in order to secure an ultraviolet light path for curing the ultraviolet curable resin 12, the distance from the center of each ultraviolet curable resin 12 to the end of the laser element holding member 9 or the optical element holding member 10 is determined by the laser element holding member 9. It is preferable that the gap be equal to or less than five times the gap between the laser element fixing portion 13 and the gap between the optical element holding member 10 and the optical element fixing portion 14 (height of the ultraviolet curable resin 12).

  Further, the ultraviolet curable resin 12 having a glass transition temperature of 110 ° C. or lower can reduce dimensional displacement due to secular change, and the laser element holding member 9, the optical element holding member 10, the laser element fixing portion 13, and the like. While peeling from the optical element fixing | fixed part 14 can be prevented, the movement of the laser diode 1 and the collimator lens 2 in the optical axis direction can be made small.

  Furthermore, in order to facilitate placing the ultraviolet curable resin 12 in a columnar shape, as illustrated in FIG. 8, at least one of the laser element holding member 9, the optical element holding member 10, the laser element fixing portion 13, and the optical element fixing portion 14. In any case, a recess 16 for receiving the ultraviolet curable resin 12 may be formed. Since the recess 16 holds the ultraviolet curable resin 12, even if the ultraviolet curable resin 12 is placed high, it is difficult for the liquid to drip. In addition, the recess 16 serves as a mark for a position where the ultraviolet curable resin 12 is placed when the light source device 8 is assembled, and extends from the center of the ultraviolet curable resin 12 to the end of the laser element holding member 9 or the optical element holding member 10. The distance can be as designed.

  Further, as illustrated in FIG. 9, at least one of the laser element holding member 9, the optical element holding member 10, the laser element fixing portion 13, and the optical element fixing portion 14 is provided with a protrusion 17 embedded in the ultraviolet curable resin 12. May be. By placing the ultraviolet curable resin 12 around the protrusion 17, the ultraviolet curable resin 12 can be held on the protrusion 17, and the ultraviolet curable resin 12 can be easily formed in a columnar shape. Further, the protrusion 17 also serves as a mark for a position where the ultraviolet curable resin 12 is to be placed.

  Further, as illustrated in FIG. 10, the small hole 18 is provided at a position where the ultraviolet curable resin 12 of at least one of the laser element holding member 9, the optical element holding member 10, the laser element fixing portion 13, and the optical element fixing portion 14 is placed. May be provided. The ultraviolet curable resin 12 may be provided with the small hole 18 as a mark, or the ultraviolet curable resin 12 may be injected from the small hole 18. Further, the small holes 18 can be used as an optical path of ultraviolet rays for curing the ultraviolet curable resin 12.

  Further, FIG. 11 shows a light source device 8b according to a third embodiment of the present invention. In the present embodiment, the holder 11 further includes a laser element holding member 9 and a laser element fixing portion 13 formed of a columnar ultraviolet curing resin 12 on the housing 19 that holds the polarizer 3 of FIG. The gap and the same gap as the gap between the optical element holding member 10 and the optical element fixing portion 14 are attached. The columns of the ultraviolet curable resin 12 that joins the holder 11 and the housing 19 are the same height on the same side in the optical axis direction as the columns of the ultraviolet curable resin 12 that join the laser element holding member 9 and the optical element holding member 10. It is so arranged.

  In the present embodiment, when the ultraviolet curable resin 12 contracts, the laser element holding member 9 and the optical element holding member 10 move by the same distance to the laser diode 1 side (laser light upstream side) in the optical axis direction. Are moved to the collimator lens 2 side (laser beam downstream side) in the optical axis direction by the same distance on the housing 19. As a result, the movement of the laser element holding member 9 and the optical element holding member 10 in the optical axis direction is canceled out, and the laser diode 1 and the collimator lens 2 not only keep the distance from each other but also move in the optical axis direction. According to this configuration, it is possible to provide a light source device that employs a lens that focuses laser light at a predetermined position as an optical element and has no focus error.

  Moreover, like the light source device 8c of 4th Embodiment of this invention shown in FIG. 12, this invention is applicable also to the light source device which has a member like the mirror 20 which bends a laser beam as an optical element. In the present embodiment, the outer peripheral portion of the mirror 20 also serves as an optical element holding member. In addition, the mounting surface 14a of the optical element fixing portion 14 of the present embodiment is inclined with respect to the optical axis, but the columns of the ultraviolet curable resin 12 for mounting the mirror 20 on the optical element fixing portion 14 are arranged in parallel to the optical axis. And has the same height in the optical axis direction as the other columns of the ultraviolet curable resin 12.

  Moreover, you may attach the holder 11 in the flame | frame 21 with the pillar of the ultraviolet curable resin 12 like the light source device 8d of 5th Embodiment of this invention shown in FIG.

  Furthermore, FIG. 14 shows a light source device 8e according to a sixth embodiment of the present invention. In the present embodiment, the optical elements are the collimator lens 2 and the cylindrical lens 22, and the optical element holding member is the lens barrel 23 that holds the collimator lens 2 and the cylindrical lens 22. The cylindrical lens 22 further shapes the laser beam shaped by the collimator lens 2 into parallel rays so that the laser beam is focused on the photoconductor 7 only in the main scanning direction in the print head of FIG. In this embodiment, even if the ultraviolet curable resin 12 expands and contracts, the distance between the laser diode 1 and the collimator lens 2 is not changed, and the position of the cylindrical lens 22 in the optical axis direction is not changed. It is possible to irradiate a laser beam with a focus.

FIG. 3 is a perspective view illustrating a configuration of a printer head to which the light source device of the invention is applied. The disassembled perspective view of the light source device of 1st Embodiment of this invention. The side view of the light source device of FIG. The top view of the light source device of FIG. The disassembled perspective view of the light source device of 2nd Embodiment of this invention. The side view of the light source device of FIG. The top view of the light source device of FIG. Sectional drawing which shows the 1st modification of the arrangement part of the photocurable resin of this invention. Sectional drawing which shows the 2nd modification of the arrangement part of the photocurable resin of this invention. Sectional drawing which shows the 3rd modification of the arrangement part of the photocurable resin of this invention. The side view of the light source device of 3rd Embodiment of this invention. The side view of the light source device of 4th Embodiment of this invention. The top view of the light source device of 5th Embodiment of this invention. The side view of the light source device of 6th Embodiment of this invention. The side view of the light source device which attached the optical element with photocuring resin. The side view when photocuring resin contracts in the light source device of FIG.

Explanation of symbols

1 ... Laser diode (laser element)
2 ... Collimator lens (optical element)
8, 8a, 8b, 8c, 8d, 8e ... Light source device 9 ... Laser element holding member 10 ... Optical element holding member 11 ... Holder 12 ... UV curable resin (photo curable resin)
DESCRIPTION OF SYMBOLS 13 ... Laser element fixing | fixed part 14 ... Optical element fixing | fixed part 15 ... Base part 16 ... Depression 17 ... Protrusion 18 ... Small hole 19 ... Housing 20 ... Mirror (optical element and optical element holding member)
21 ... Frame 22 ... Cylindrical lens (optical element)
23 ... Lens barrel (optical element holding member)

Claims (11)

A laser element holding member that holds a laser element that emits laser light;
An optical element holding member for holding an optical element for shaping the laser beam;
A laser element fixing part for attaching the laser element holding member; an optical element fixing part for attaching the optical element holding member; and a holder comprising a base part for holding the laser element fixing part and the optical element fixing part. ,
The laser element holding member and the optical element holding member are respectively on the same side in the optical axis direction of the laser beam by the photo-curing resin disposed at a plurality of positions with respect to the laser element fixing portion and the optical element fixing portion. A light source device for an image forming apparatus, wherein the light source device is attached with a gap.   2. The light source device for an image forming apparatus according to claim 1, wherein the base is integrally formed with the base portion and the optical element fixing portion.   The image according to claim 1, wherein the optical element fixing portion has an attachment surface orthogonal to the optical axis of the laser light, and the optical element holding member is attached to the attachment surface. Light source device for forming apparatus.   The light source device for an image forming apparatus according to claim 1, wherein the optical element has a function of a collimator lens and a cylindrical lens.   The light source device for an image forming apparatus according to claim 1, wherein the photocurable resin has a glass transition temperature of 110 ° C. or less. The gap between the laser element holding member and the laser element fixing portion and the gap between the optical element holding member and the optical element fixing portion are 0.1 mm or more and less than 1 mm, respectively.
6. The light source device for an image forming apparatus according to claim 1, wherein the photocurable resin has an uncured viscosity at 25 ° C. of 6000 mPa · s or more and 30000 mPa · s or less.   The light source device for an image forming apparatus according to claim 1, wherein the photocurable resin is an ultraviolet curable resin.   8. The distance from the center of the photo-curing resin to the end of the optical element holding member is not more than 5 times the gap between the optical element holding member and the optical element fixing portion. The light source device for an image forming apparatus according to any one of the above.   9. A recess for receiving the photo-curing resin is provided in at least one of the laser element holding member, the laser element fixing portion, the optical element holding member, and the optical element fixing portion. The light source device for an image forming apparatus according to any one of the above.   10. A projection embedded in the photo-curing resin is provided on at least one of the laser element holding member, the laser element fixing portion, the optical element holding member, and the optical element fixing portion. The light source device for an image forming apparatus according to any one of the above.   The small hole is provided in the position where the said photocurable resin is arranged in at least any one of the said laser element holding member, the said laser element fixing | fixed part, the said optical element holding member, and the said optical element fixing | fixed part. The light source device for an image forming apparatus according to any one of 1 to 10.

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