JP2000267032A - Light source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a light source device constituted so that the alignment of the optical axes and the foci of a light source part and a beam shaping lens can be easily adjusted with high accuracy and it can be adjusted even in an image forming device specially having plural light source parts. SOLUTION: This light source device 10 is constituted so that a circuit board 14 holding a semiconductor laser 12 can be moved along the side wall 63 of an optical box 62 and the fitting position thereof is adjusted by an adjustment screw with a fixed flange 16. Then, a lens holding pedestal 20 to which a collimator lens 22 is fitted can be moved in an optical axis direction independently of the board 14. Besides, the pedestal 20 is pressed to the laser 12 side by the leaf spring part 30A of a spring 30 and interposed between an adjustment screw 18. Thus, the alignment of the optical axes is executed by operating the board 14 from the outside of the box 62 and moving it within a plane surface being vertical to the optical axis. Besides, the alignment of the foci is executed by moving the screw 18 forward and backward and moving the pedestal 20 in the optical axis direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light source device, and more particularly, to a light source device which is provided in an image forming apparatus such as a laser printer or a digital copying machine and has a position adjusting mechanism between a laser light source and a beam shaping lens. About.

[0002]

2. Description of the Related Art Generally, a light source device used in an image forming apparatus such as a laser printer or a digital copying machine emits a laser beam for forming an electrostatic latent image on a photosensitive drum from a laser light source. The laser beam is converted into a light beam of a predetermined shape by an optical system including a collimator lens and an aperture stop.

FIG. 8 shows a laser printer as an example of an image forming apparatus equipped with such a light source device.

[0004] The laser printer 100 includes a photosensitive drum 102 rotating at a constant speed, a charging device 104 disposed around the photosensitive drum 102 to uniformly charge the surface of the photosensitive drum 102, and a photosensitive drum 102 based on image data. Drum 102
An optical scanning device 106 for forming an electrostatic latent image on the surface, a developing device 108 for developing the electrostatic latent image, a transfer device 112 for transferring a toner image obtained by development to a recording sheet 110, and a transferred toner The image forming apparatus includes a fixing device 114 that fixes an image on the recording paper 110 and a device control unit 116 (Main Control Unit) that controls the entire laser printer 100.

[0005] The laser printer 100 is connected to a printer control device 118 typified by a computer, for example, by a cable 119.
8 to print out based on the image data transmitted from.

FIG. 9 shows an optical scanning device mounted on the laser printer.

The optical scanning device 106 includes a semiconductor laser device 120 as a light source, a semiconductor laser control device 122 controlled by a device control section 116 to control the semiconductor laser device 120 to be turned on / off (modulated) according to an image signal, A collimator lens 130 for converting a laser beam (divergent light beam) emitted from the laser 120 into a substantially parallel light beam, and an aperture stop 132 for shaping the substantially parallel laser light beam
A cylindrical lens 134 through which the shaped laser beam passes, a first plane mirror 136 that reflects the laser beam from the cylindrical lens 134 and makes it incident on the rotating polygon mirror 138, and rotates at a constant speed in the direction of arrow E; A rotary polygon mirror 138 that repeatedly deflects a laser beam emitted in accordance with an image signal, and a scanning lens group that forms an image of the deflected laser beam on the surface of the photosensitive drum 102 and scans the main scanning direction (the direction of arrow F). 140 and scanning lens group 1
A second plane mirror 142 and a cylindrical mirror 144 for guiding the scanning beam from 40 to the photosensitive drum 102
A dust-proof glass 145 for preventing dust and the like from entering the photosensitive drum 102; and an SOS (Start of Scan) sensor for detecting a scanning beam, determining an image signal modulation in each scan, and determining a scan start timing. 1
48 and the scanning beam from the scanning lens group 140
And a third flat mirror 150 that is incident on the sensor 148.

In such an optical scanning device, generally, the optical axis is adjusted so that the laser beam from the laser light source is aligned with the optical axis of the collimator lens, and the spot diameter of the laser beam formed on the photosensitive drum is adjusted. It is necessary to adjust the focus position (focus adjustment) to a predetermined diameter, and these adjustment mechanisms are provided in a light source device provided in the optical scanning device.

That is, the laser light source and the collimator lens installed in the light source device are configured so that their relative positions can be changed, and the optical axis and the focus can be adjusted by adjusting the positional relationship between the two components within a predetermined accuracy. Adjustments are made.

In these adjustments, a jig (a photodetector or the like) for detecting a laser beam characteristic is used, and the optical scanning optical system emitted from the laser light source is mounted on the jig installed at a position equivalent to the surface of the photosensitive drum. Image the laser beam that passed through,
A method of monitoring the output at this time is generally used.

By adopting such an adjustment system, there is a merit that the accuracy error of the optical box and the optical parts constituting the optical scanning device can be absorbed and the cost of the device can be suppressed.

FIGS. 10 and 11 show examples of a light source device provided with an adjustment mechanism.

FIG. 10 (conventional example 1: JP-A-5-29730)
30), the collimator lens unit 91 holding the collimator lens 41 is positioned by pins (not shown) and fixed to the side wall of the optical box.

The semiconductor lasers 25 arranged at predetermined intervals substantially on the optical axis of the collimator lens 41 are made of an elastically deformable material such as a sheet metal, and the deformation of the collimator lens 41 in the optical axis direction. Is mounted on an LD mounting member 81 having a notch for facilitating the mounting.
A spacing member 96 provided on the back of the semiconductor laser 25
The adjustment screw 86 screwed to the adjustment screw holding member 82 is in contact with the adjustment screw holding member 82. The adjustment screw holding member 82 is fixed to the LD mounting member 81 by the adjustment screw holding member fixing screws 83 and 84.
It is fixed to.

Thus, the adjusting screw 86 is moved forward and backward, and the LD holding portion 87 to which the semiconductor laser 25 is attached is deformed in the optical axis direction (the direction of arrow Z1 in the figure), so that the collimator lens 41 and the semiconductor laser 25 are moved. Perform interval adjustment (focus adjustment).

The LD mounting member 81 moves within a plane perpendicular to the optical axis of the collimator lens 41 (arrows X1 and X2 in the figure).
(Y1 direction) to enable the collimator lens unit 91
By moving the LD mounting member 81, the optical axis adjustment for aligning the optical axes of the collimator lens 41 and the semiconductor laser 25 is performed.

Recently, as shown in FIG. 11 (conventional example 2), the structure of the light source device has been further simplified, and at the same time, unnecessary radio noise (radio noise generated from a cable for supplying a current or a signal to a semiconductor laser) has been reduced. To suppress outbreak,
A light source integrated substrate type device in which a laser light source body is mounted on a control circuit board is also widely used.

The optical axis adjustment in the light source device 124 is as follows.
The circuit board 123 (light source integrated board) attached to the side wall 107A of the optical box 107 with the adjusting screw 126 is attached to the optical box 1
Collimator lens 1 placed on pedestal 131 in
30 in a plane perpendicular to the optical axis (arrows X2 and Y2 in the figure).
Direction), and the laser emission optical axis of the semiconductor laser 121 directed to the inside of the optical box 107 through the mounting hole 107B of the side wall 107A is aligned with the optical axis of the collimator lens 130.

The focus adjustment is performed by accessing a collimator lens 130 that can be moved only in the optical axis direction (direction of arrow Z2 in the figure) by using a lens adjustment jig (jig finger or the like). Adjust the interval. After the focus adjustment, the collimator lens 130 is fixed with an adhesive or the like.

[0020]

However, image forming apparatuses in recent years are required to have higher resolution.
In an optical scanning device with a small beam spot diameter corresponding to this high resolution, it is necessary to adjust the optical axis and the focus with higher accuracy such as several tens of microns to several microns.

Further, there is a type of optical scanning device which responds to recent high-speed and high-resolution operation, in which a plurality of laser light sources are provided in one optical box to perform a plurality of scans, and each scanning line of the plurality of laser light sources is provided. For each color [Y
(Yellow), M (magenta), C (cyan), Bk
(Black)], an optical scanning device for a color image forming apparatus has also been developed.

In the case where the optical scanning device having a plurality of laser light sources has a plurality of optical systems, each component of the optical system is accommodated in a limited space (in the optical box) of the image forming apparatus. However, the mounting density of the components must be increased, and this also complicates the layout of the components and the optical path of the laser beam. That is, around the beam shaping lens such as the collimator lens, various optical components forming the optical system and their holding members are arranged. In addition to the optical path of the laser beam passing through the beam shaping lens, these optical components are also provided. There are various optical paths formed by

Therefore, in such an optical scanning device, a more difficult operation of adjusting a plurality of laser light sources and optical systems with high accuracy in a space (narrow space) with a high mounting density is required.

On the other hand, the conventional example 1 described above (FIGS. 9 and 1)
The optical axis and focus adjustment by the light source device 0) are performed by operating only the laser light source unit side from the outside of the optical box (X1, Y).
1, Z1 direction), so that the adjustment can be performed without being affected by the mounting density of the optical components and the like arranged in the optical box.
However, when the adjustment precision becomes severe, the adjustment deviation due to the mutual influence in each adjustment cannot be ignored.

In other words, this is a structure in which the movement (focus adjustment) of the semiconductor laser 25 in the direction of the optical axis utilizes the deformation of the LD holding portion 87 holding the semiconductor laser 25. The torsion of the part 87 and the like causes the laser emission optical axis of the laser light to be slightly shifted from the optical axis of the collimator lens 41. If the deviation does not fall within the allowable accuracy of the optical axis adjustment, the optical axis and the focus adjustment are repeatedly performed, resulting in a problem that the workability is reduced.

In the case of Conventional Example 2 (FIG. 11), the semiconductor laser 121 integrated with the control circuit board 123 and the collimator lens 130 mounted in the optical box 107 are used.
And have a structure that can move independently of each other, so that there is no problem of mutual influence that occurs during adjustment.

However, at the time of focus adjustment, the optical box 10
In order to move the collimator lens 130 in 7 in the optical axis direction by accessing it from above the optical box 107 with a lens adjusting jig or the like, the collimator lens 130 is moved by a large number of optical components or a complicated optical path. The problem that access becomes difficult occurs. Here, if these optical paths are blocked, the adjustment parts can be easily accessed. However, this makes it impossible to perform real-time adjustment while detecting the characteristic value on the image plane by the above-described light detection jig or the like (or the photosensitive drum), and thus the work time is greatly increased.

After the adjustment, the collimator lens needs to be fixed with an adhesive or the like, so that the workability is poor.

According to the present invention, in consideration of the above fact, the alignment of the optical axis and the focal position between the light source unit and the beam shaping lens can be easily adjusted even with high accuracy, and particularly in an image forming apparatus having a plurality of light source units. It is another object of the present invention to provide a light source device that can also adjust.

[0030]

According to a first aspect of the present invention, there is provided a light source device which is movable in a plane perpendicular to an optical axis and whose mounting position is adjustable from outside an optical box. A holding member for holding a beam shaping lens arranged on the optical axis, which is movable independently of the portion in the optical axis direction,
The light source device according to claim 1, further comprising an adjusting unit that adjusts a focal position of the beam shaping lens by operating the holding member from the light source unit side.

That is, in the present invention, the light source unit can move in a plane perpendicular to the optical axis, and the mounting position can be adjusted from outside the optical box. Further, the holding member for disposing the beam shaping lens on the optical axis of the light source unit can be moved in the optical axis direction independently of the light source unit. There is provided an adjusting means for adjusting the focal position of the beam shaping lens with respect to the light source section by operating the holding member from above.

Thus, in each adjustment for aligning the relative positions of the light source unit and the beam shaping lens, the optical axis alignment is
This is performed by operating the light source unit from the outside of the optical box and moving the light source unit in a plane perpendicular to the optical axis. The focus position is adjusted by moving the holding member in the optical axis direction by adjusting means that can be operated from the light source unit side.

As described above, since the position adjustment of the light source unit and the beam shaping lens is performed from the light source unit side (outside the optical box), the adjustment operation inside the optical box becomes unnecessary. This means that, for example, in order to operate the light source unit or the beam shaping lens disposed inside the optical box, it is not necessary to bring an adjustment jig or the like close to or in contact with these components.

Therefore, even in a color image forming apparatus or the like having a plurality of light source sections and having a complicated optical path,
This eliminates the problem that the optical path is blocked by a jig or the like at the time of adjustment, or that the jig or the like interferes with the light source or other optical system components arranged near the beam shaping lens, making it difficult to operate the component. The adjustment can be performed while checking the laser beam characteristics (the spot light to be imaged) on the surface. Therefore, these adjustment operations are facilitated, and the structure of a jig or the like used for the adjustment can be simplified.

Further, the light source section and the beam shaping lens are provided independently of each other, and are configured to move individually, so that either the light source section or the beam shaping lens can be moved. , The other mounting position is not affected. Therefore, even in an image forming apparatus with high adjustment accuracy, there is no waste due to repeated adjustment (optical axis and focus position adjustment) and the like, and the work time is reduced.

According to a second aspect of the present invention, in the light source device according to the first aspect, the adjusting means includes an elastic member for urging the holding member in the direction of the light source unit, and is screwed from the light source unit side. And a screw member abutting on the holding member.

That is, in the second aspect of the present invention, the holding member is urged toward the light source by the elastic member, and the holding member is in contact with a screw member screwed in from the light source.

Thus, the holding member can be easily moved only by the operation of moving the screw member forward and backward, and the focal positions of the light source unit and the beam shaping lens are adjusted. In addition, fine adjustment is possible by using a screw member for the adjustment means,
Even when the adjustment is performed with high accuracy, it can be easily performed.

Since the holding member for holding the beam shaping lens is sandwiched between the elastic member and the screw member, the adjusted position does not easily shift. Further, work such as bonding for fixing the beam shaping lens is not required, and the work time is shortened.

According to a third aspect of the present invention, in the light source device according to the second aspect, a female screw portion is provided at a core portion of a fixing screw which is fixed after adjusting a mounting position of the light source portion from outside the optical box. The screw member is formed and screwed into the female screw portion to penetrate.

In other words, according to the third aspect of the present invention, the screw member is screwed and penetrated to the female screw portion formed on the core portion of the fixing screw to be fixed after adjusting the mounting position of the light source portion. In this state, it is in contact with a holding member that holds the beam shaping lens.

As described above, since the screw member is provided integrally with the fixing screw of the light source unit, it is not necessary to separately provide an installation space for the screw member, and the light source unit can be downsized.

According to a fourth aspect of the present invention, in the light source device according to any one of the first to third aspects, the light source unit is mounted on a top plate of an optical box, and is emitted from the light source unit to form the beam shaping lens. Is reflected by a reflecting mirror and guided to an optical system.

That is, in the invention of claim 4, the light source is mounted on the top plate of the optical box, and the beam emitted from the light source and passed through the beam shaping lens is reflected by the reflection mirror and guided to the optical system. Is done.

Accordingly, even when there is a restriction on the light source unit mounting space on the side wall of the optical box, or in an image forming apparatus having a plurality of light source units whose mounting density is increased due to the layout of the optical system components and the like, the upper part of the optical box can be used. By arranging the light source unit on the top plate of the optical box using the empty space, it is possible to store the light source unit in a predetermined space. Further, in this case, a beam emitted downward from the light source unit can be guided to the optical system (lateral direction) by a simple structure in which only a reflection mirror is provided.

Further, according to the first aspect of the present invention, since each adjustment of the optical axis and the focus position can be performed from the light source unit side (outside the optical box), the adjustment can be performed even when the light source unit is mounted on the top plate of the optical box. Yes, for example, there is no need to provide a hole for inserting a jig in the side wall of the optical box or the top plate of the optical box in order to insert an adjustment jig or the like into the optical box and operate each component. The structure of the top plate can be simplified.

[0047]

An embodiment of the present invention will be described below with reference to the drawings.

1 to 4 show the overall configuration of an optical scanning device to which the light source device according to the embodiment of the present invention is applied. The optical scanning device here is of a type corresponding to colorization mounted on a color image forming apparatus, and a plurality of optical scanning devices for scanning a photosensitive drum for each color (Y, M, C, Bk). System and a plurality of light source devices.

The outline of the optical system arranged inside the optical box 62 of the optical scanning device 60 is as follows: the light source block 11 including the light source device 10, the plane mirrors 64 and 74, and the Fθ lens group 66.
, A rotary polygon mirror 70 provided on a deflector 68, and a cylindrical mirror 78 provided on a cylindrical mirror holding plate 76, and a photosensitive device corresponding to each color is provided below the optical scanning device 60. Body drum 80
Is installed.

First, the light source device according to this embodiment will be described in detail. However, in the present embodiment, the four light source blocks provided are formed as one set of two, and are arranged symmetrically on both sides of the rotary polygon mirror. Therefore, one set is used and further installed on the side wall of the optical box. A description will be given of the light source block.

The light source device 10 shown in FIGS. 5 to 7 includes a circuit section (not shown) for controlling the lighting of the laser beam of the semiconductor laser 12 on the side wall 63 of the optical box 62, and the semiconductor laser 12 is mounted. A circuit board 14 provided substantially at the center of the surface 14A is attached. The semiconductor laser 12 has a substantially cylindrical shape, and an emission optical axis (hereinafter, referred to as a “laser optical axis”) of a laser beam with respect to the mounting surface 14A is aligned substantially perpendicularly.

Further, mounting holes 14B are provided on both sides of the semiconductor laser 12 in the longitudinal direction of the circuit board 14 (in the direction of the arrow X in the figure), and adjustment holes 14C are provided outside the mounting holes 14B. I have.

At a position corresponding to the semiconductor laser 12 on the side wall 63, a hole 63A having an inner diameter larger than the outer diameter of the semiconductor laser 12 by a predetermined dimension is provided.
The circuit board 14 is attached to the side wall 63 with the semiconductor laser 12 penetrating the 3A. Therefore, the laser beam of the semiconductor laser 12 is emitted in a direction substantially perpendicular to the side wall 63 toward the inside of the optical box 62.

Further, the diameter of the mounting hole 14B is formed on the side wall 63 at a position corresponding to the mounting hole 14B provided in the circuit board 14.
A screw hole 63B smaller than the inner diameter of the screw hole 63B is formed. The screw portion 16B of the fixing screw 16 with the fixed flange provided with the head flange 16A is screwed into the screw hole 63B. Therefore, the mounting position of the circuit board 14 movable along the side wall 63 (in the directions of arrows X and Y in the figure) can be adjusted within a predetermined range by the adjustment screw 16 with the fixing flange, and is fixed to the side wall 63. Is done.

A female screw 16C penetrating in the axial direction is formed at the core of the adjusting screw 16 with a fixed flange. An adjusting screw 18 having a longer overall length than the adjusting screw 16 with the fixed flange is formed on the female screw 16C. Are combined.

Adjusting Screw 18 and Adjusting Screw 1 with Fixed Flange
As shown in FIG. 7, the positional relationship between the adjusting screw 6 and the adjusting screw 6 is such that the distal end of the adjusting screw 18 protrudes from the distal end 16D of the adjusting screw 16 with a fixed flange.

On the other hand, in front of the semiconductor laser 12, a lens holding base 20 for disposing a collimator lens 22 (beam shaping lens) for shaping a laser beam on the laser optical axis of the semiconductor laser 12 is provided. I have. A collimator lens 22 is provided substantially at the center of the lens hole 20A provided in the lens holding base 20 in the optical axis direction (the direction of arrow Z in the drawing).
Is attached. A concave portion 20C is formed on the lower surface of the lens holding base 20 by leg portions 20B protruding at both ends in the width direction (the arrow X direction in the figure).

The lens holding base 20 is located on the bottom surface 6 of the optical box 62.
A guide portion 61A having a width slightly smaller than the width of the concave portion 20C and projecting therefrom is formed at a predetermined position on the side wall 1 in a direction substantially perpendicular to the side wall 63. The concave portion 20C of the lens holding base 20 is slidably fitted to the guide portion 61A, so that the lens holding base 20 can be moved in a direction substantially perpendicular to the side wall 63 of the optical box 62 (in the figure). (Z direction).

Therefore, the moving direction of the lens holding base 20 is substantially parallel to the laser optical axis of the semiconductor laser 12, and
Further, the distance between the semiconductor laser 12 and the collimator lens 22 in the optical axis direction can be adjusted.

Further, since the dimensional difference between the fitting portion of the concave portion 20C and the guide portion 61A is small, the lens holding base 20 is inclined with respect to the laser optical axis, or is not in the optical axis direction (for example, (Eg, orthogonal directions).

The lens holding base 20 (collimator lens 2)
A plate-shaped spring 30 is attached to the bottom surface 61 of the optical box 62 by a spring attachment screw 32 on the side of the laser beam transmission exit side (2) opposite to the semiconductor laser 12).

The width direction of the spring 30 (the direction of the arrow X in the figure)
The size is substantially equal to the width of the lens holding base 20, and from both sides in the width direction of the edge of the spring 30 on the side of the semiconductor laser 12, a leaf spring portion 30A extends obliquely upward toward the semiconductor laser 12. Is out.

The bent portion 30B formed in the middle of the plate spring portion 30A in the longitudinal direction is in contact with the lens holding base 20, so that the lens holding base 20 applies the elastic force (predetermined force) of the plate spring portion 30A. ), And is held in contact with the tip 18A of the adjusting screw 18 projecting from the tip 16D of the adjusting screw 16 with the fixed flange.

By moving the adjusting screw 18 forward and backward, the lens holding base 20 moves in the optical axis direction, and the leaf spring portion 30A makes the both side edges of the lens holding base 20 in the width direction substantially equal in force. By pressing the recess 20C.
It can slide smoothly without being caught by the guide part 61A.

The structure of the light source device 10 installed on the side wall 63 of the optical box 62 has been described above. The light source device 10 has the aperture stop 36 arranged in this order on the laser beam transmission exit side of the lens holding base 20. And cylindrical lens 38
The light source block 11 is configured by adding (FIG. 4).

The configuration of the optical scanning device 10 arranged on the upper surface of the cylindrical mirror holding plate 76 is also substantially the same as that described above.

Circuit board 14 holding semiconductor laser 12
Is attached to the upper surface of the cylindrical mirror holding plate 76 by the adjusting screw 16 having a fixed flange to which the adjusting screw 18 is screwed.
The lens holding base 20 to which is attached, and the spring 30
The optical box 62 is installed on an inner vertical wall (not shown).

However, on the laser beam transmission exit side (lower side) of the lens holding base 20, there is provided a plane mirror 40 which is arranged at a predetermined angle with respect to the optical axis and guides the laser beam into the optical box 62. is set up.

Hereinafter, the arrangement of each optical component of the optical scanning device 60 and the optical path of the laser beam will be described. The optical system including the light source block 11 constitutes an optical system that is symmetrical on both sides of the rotary polygon mirror 70 as described above. Therefore, the optical system on one side will be described here. Also for convenience,
The laser beam from the optical scanning device 10 installed on the side wall 63 of the optical box 62 is called “beam A”, and the laser beam from the optical scanning device 10 installed on the cylindrical mirror holding plate 76 is called “beam B”.

As shown in FIG. 4, in each light source block 11, beams A and B emitted from the semiconductor laser 12 are emitted.
The (divergent light beam) is shaped into a beam (substantially parallel light beam) by the collimator lens 22, and the light beam width is regulated by the aperture stop 36. (Long) linear light flux.

After passing through the cylindrical lens 38, the beam A is directly incident on the plane mirror 64, and the beam B is made substantially the same direction as the beam A by reflection on the plane mirror 40 and is incident on the plane mirror 64. However, the beams A and B here enter the plane mirror 64 with a predetermined angle difference in the sub-scanning direction, and are reflected toward the rotary polygon mirror 70.

In this case, both beams are rotated by the polygon mirror 70.
When the light is reflected and deflected by the rotating polygon mirror 70, the light is transmitted through the Fθ lens group 66 in the main scanning direction, and further, the beam is incident on the rotating polygon mirror 70 from the center of the scanning angle formed by the reflected and deflected beam. (A front-incidence double-pass optical system).

The beams A and B reflected on the plane mirror 64 and incident on the rotary polygon mirror 70 from obliquely above indicate the incident position in the height direction on the rotary polygon mirror 70 by the incident angle in the sub-scanning direction. Is made lower than the beam A whose incident angle is made smaller. As a result, an interval in the sub-scanning direction between the two beams on the rotating polygon mirror 70 is secured. Further, the interval between the beams A and B reflected and deflected by the rotary polygon mirror 70 in the sub-scanning direction gradually increases, and the interval between the two beams secured after passing through the Fθ lens group 66 is increased. Thus, the arrangement of each optical component is facilitated.

The beams A and B deflected by the rotary polygon mirror 70 and transmitted through the Fθ lens group 66 are given a predetermined amount in the sub-scanning direction as shown in FIG. The light is reflected at an angle and passes above the rotary polygon mirror 70 to reach each of the cylindrical mirrors 78.

The beams A and B reflected downward by the cylindrical mirror 78 pass through the side of the Fθ lens group 66, that is, pass through the inside of the optical scanning device 60 again in the vertical direction, so that each photosensitive member It reaches the drum 80.

The above is the optical system on one side and the optical path of the laser beam by the optical system. Although the description is omitted, the other optical system located on the opposite side of the rotary polygon mirror 70 is also used for each optical component. The arrangement and the optical path of the laser beam are the same. 2 and 3, “beam C” corresponds to “beam A”, and “beam D” corresponds to “beam B”.

As described above, the optical scanning device 60 of the present embodiment
In the optical system of (1), two beams on one side of the rotary polygon mirror 70 are simultaneously deflected and scanned as a total of four beams on both sides, and black (Bk) and yellow (Y) are emitted by these laser beams emitted from each light source device 10. ), Magenta (M), and cyan (C) on the photosensitive drum 80 corresponding to each color.

In the optical scanning device 60 of the present embodiment, by taking the miniaturization into consideration, the optical path of each laser beam is formed by arranging the respective optical components as described above without waste, thereby reducing the dimension in the height direction. The size is reduced and the photoconductor drum 80 is arranged close to the photoconductor drum 80.

In this case, however, by increasing the mounting density in the optical box 62, a holding portion for the optical components can be formed without interrupting the laser beam scanned between the optical components. It is not easy to make each adjustment.

The cylindrical mirror 78 is attached not to the optical box 62 but to a cylindrical mirror holding plate 76 disposed at the upper part, in consideration of the rigidity of the entire optical scanning device 60 and the workability of assembly and adjustment. This cylindrical mirror holding plate 76
Is accurately fixed to the optical box 62. Therefore, in this embodiment, the optical path of the laser beam from the semiconductor laser 12 to the photosensitive drum 80 is formed by placing the cylindrical mirror holding plate 76 on the optical box 62.

For this reason, in the movement adjustment of the collimator lens 22 in the focus adjustment, the above-described conventional example 2 is used.
In the configuration described above, it is difficult to access the collimator lens 22 inside the optical box 62 with a jig or the like.

Next, a method of adjusting the optical axis and the focus of the optical scanning device 10 will be described.

The optical axis is adjusted by rotating a jig having a photodetector from between 8 (in the direction of arrow G in the figure) of the cylindrical mirror 78 of the optical scanning device 60 shown in FIGS.
The jig finger is inserted from the outside of the optical box 62 into the adjustment hole 14C of the circuit board 14 from the outside of the optical box 62 based on the position information of the laser beam before deflection which is incident on the rotary polygon mirror 70 and the circuit board 14 is The semiconductor laser 12 is moved in a plane perpendicular to the axis (the X and Y directions) so that the laser optical axis of the semiconductor laser 12 matches the optical axis of the optical system including the collimator lens 22.

After the adjustment, the circuit board 14 is fixed to the side wall 63 of the optical box 62 or the cylindrical mirror holding plate 76 by the adjusting screw 16 with fixing flange.

Next, focus adjustment is performed on the photosensitive drum 80.
The adjusting screw 18 screwed to the adjusting screw 16 with the fixed flange is advanced and retracted so that the beam spot detected by the photodetector installed at the position equivalent to the above has a predetermined spot diameter, and the lens holding base 20 is laser-driven. It is performed by moving in the optical axis direction.

As described above, in the light source device 10 of the present embodiment, the semiconductor laser 12 and the collimator lens 2
Since the position adjustment 2 is performed from the semiconductor laser 12 side (outside the optical box), the adjustment operation inside the optical box 62 is not required.

Therefore, even in a color image forming apparatus or the like having a plurality of semiconductor lasers 12 as in this embodiment and having a complicated optical path, the optical path may be blocked by a jig or the like during adjustment, or the semiconductor laser 12 Or collimator lens 2
The other problem that the optical component and the like arranged near the lens holding base 20 interfere with the jig and the like and the component becomes difficult to operate is eliminated, and the spot light imaged on the light detection jig and the like is eliminated. It is possible to adjust while confirming.

The lens holding base 20 is urged toward the semiconductor laser 12 by a spring 30 so that the semiconductor laser 1
Since the lens holding base 20 is in contact with the adjustment screw 18 screwed in from the second side, the lens holding base 20 can be moved only by the operation of moving the adjustment screw 18 forward and backward, and fine adjustment for high adjustment accuracy is also possible.

Further, since the lens holding base 20 for holding the collimator lens 22 is sandwiched between the spring 30 and the adjusting screw 18, the position after adjustment does not easily shift, and the lens holding base 20 for fixing the collimator lens 22 is not fixed. Work such as bonding is not required.

The semiconductor laser 12 and the collimator lens 22 are provided independently of each other, and are configured to move individually, so that the circuit board 14 (semiconductor laser 12) or the lens holding base 20 By moving either one of the (collimator lens 22),
The other mounting position is not affected. Therefore,
Even in an image forming apparatus with high adjustment accuracy, waste due to repeated adjustment (optical axis and focus position alignment) and the like is eliminated.

Accordingly, the work of adjusting the optical axis and the focus becomes easy, and the work time is shortened.
Also, the structure of a jig and the like used for adjustment can be simplified.

Further, the adjusting screw 18 is screwed and disposed on a female screw 16C formed on the core of the adjusting screw 16 with a fixed flange for adjusting the mounting position of the semiconductor laser 12, and the adjusting screw 18 is fixed. By being provided integrally with the adjusting screw 16 with a flange, there is no need to separately provide an installation space for the adjusting screw 18, and the circuit board 14 can be downsized.

Further, in the present embodiment in which one light source block 11 is formed as a set of two light source blocks, one of the light source blocks 11 in each set is attached to the cylindrical mirror holding plate 76, so that the optical system components and the like are provided. Even in a color image forming apparatus whose mounting density is increased by the above layout, it can be accommodated in a predetermined space. In this case, a laser beam emitted downward from the semiconductor laser 12 can be guided to the optical system (lateral direction) by a simple structure in which the plane mirror 40 is simply provided.

Here, since each adjustment of the optical axis and the focus position can be performed from the semiconductor laser 12 side (outside the optical box), the adjustment can be performed even when the semiconductor laser 12 is arranged on the upper surface of the optical box 62. In order to insert an adjustment jig and the like into the optical box and operate each component, the side wall 63 of the optical box 62 or the cylindrical mirror holding plate 7
There is no need to provide a hole or the like for inserting a jig in the optical box 62.
And the structure of the cylindrical mirror holding plate 76 can be simplified.

In the present embodiment, two adjustment screws 16 with fixed flanges are used in consideration of the stability when the circuit board 14 is fixed. However, the number of adjustment screws 16 with fixed flanges is limited to this. However, the number of adjusting screws 18 can be changed to one or three or more, and the number of adjusting screws 18 can be changed according to the number.

Further, in the present embodiment, the collimator lens 22
Is mounted on the lens holding base 20 slidable in the optical axis direction, and the movement is adjusted. However, even when movement adjustment of a cylindrical lens having a beam shaping function is required, the same structure is used. Can be adjusted.

[0097]

According to the light source device of the present invention, the optical axis and the focal position between the light source and the beam shaping lens can be easily adjusted with high precision. The adjustment can be performed even in the image forming apparatus provided with the image forming apparatus.

[Brief description of the drawings]

FIG. 1 is a perspective view of an optical scanning device equipped with a light source device according to an embodiment of the present invention.

FIG. 2 is a perspective view showing an overall configuration of an optical scanning device equipped with a light source device according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram showing an optical system and an optical path of a laser beam of the optical scanning device according to one embodiment of the present invention.

FIG. 4 is a perspective view illustrating an optical system on one side and an optical path of a laser beam of an optical scanning device equipped with a light source device according to an embodiment of the present invention.

FIG. 5 is a perspective view of a light source device according to an embodiment of the present invention.

FIG. 6 is a perspective view of the light source device according to the embodiment of the present invention as viewed from the outside of the optical box.

FIG. 7 is a top view showing an assembled state of the light source device according to one embodiment of the present invention.

FIG. 8 is a schematic diagram illustrating an entire configuration of a conventional image forming apparatus.

FIG. 9 is a schematic diagram showing an overall configuration of a conventional optical scanning device mounted on the image forming apparatus of FIG.

10A and 10B are diagrams illustrating a configuration of a conventional light source device (conventional example 1), wherein FIG. 10A is a cross-sectional view taken along line AA of FIG. 10B, and FIG. It is a plan view seen,
(C) is a top view of an LD mounting member.

11A and 11B are diagrams illustrating a configuration of a conventional light source device (conventional example 2), where FIG. 11A is a perspective view as viewed from the outside of the optical box, and FIG. 11B is a cross-sectional view as viewed from the side of the optical box. It is.

[Explanation of symbols]

Reference Signs List 10 light source device 12 semiconductor laser (light source unit) 14 circuit board (light source unit) 16 adjusting screw 16 with fixing flange (fixing screw) 16C female screw (female screw portion) 18 adjusting screw 18 (adjusting means / screw member) 20 lens holding Base 22 Collimator lens (beam shaping lens) 30 Spring (adjustment means) 40 Plane mirror (reflection mirror) 62 Optical box 76 Cylindrical mirror holding plate (top plate of optical box)

Claims (4)

[Claims] 1. A movable member in a plane perpendicular to an optical axis,
A light source section whose mounting position can be adjusted from outside the optical box,
A light source device that is movable in the optical axis direction independently of the light source unit and has a holding member that holds a beam shaping lens disposed on the optical axis. A light source device comprising an adjusting means for adjusting a focal position of the beam shaping lens by operating the light source device. 2. The apparatus according to claim 1, wherein the adjusting unit includes an elastic member for urging the holding member toward the light source unit, and a screw member screwed from the light source unit side and abutting on the holding member. The light source device according to claim 1. 3. A female screw portion is formed in a core portion of a fixing screw which is fixed after adjusting a mounting position of the light source portion from the outside of the optical box, and the screw member is screwed into the female screw portion to penetrate. The light source device according to claim 2, wherein: 4. The light source unit is mounted on a top plate of an optical box, and a beam emitted from the light source unit and passed through the beam shaping lens is reflected by a reflection mirror and guided to an optical system. Item 5. The light source device according to any one of Items 1 to 3.