JP2009222863A - Scanning optical device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a scanning optical device capable of position-regulating an optical element along a main scanning direction and a sub-scanning direction, by simple constitution. <P>SOLUTION: This scanning optical device exposes respective different photoreceptor drums with a plurality of beams deflected by a deflector, via a scanning optical system comprising a plurality of second lenses 22. The second casing portion 35 holds the second lenses 22 on a prescribed plane S. A regulation mechanism 39 is in parallel to the plane S, and regulates positions of the second lenses 22, by sliding the second lenses 22 along an x-axial direction and a y-axial direction perpendicular each other. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a scanning optical apparatus that exposes a beam onto a surface to be scanned.

  A scanning optical device described in Patent Document 1 is proposed as a compact scanning optical device that suppresses registration deviation in the sub-scanning direction between colors, suppresses a single magnification in the main scanning direction, and is suitable for high-definition printing. ing. In the scanning optical device, in order to correct the bending of the scanning line, the diffractive optical element is rotated to adjust the bending of the scanning line.

  However, the scanning optical device described in Patent Document 1 has a problem that the configuration for rotating the diffractive optical element becomes complicated and large as described below. More specifically, in the scanning optical device described in Patent Document 1, the diffractive optical element can be rotated about two axes orthogonal to each other as central axes. In the scanning optical device, in order to enable such rotation in two directions, a holding member that holds the diffractive optical element so as to be rotatable in the first direction, and a holding member that is rotatable in the second direction are held. And a chassis to be provided. Thus, in the scanning optical device, since the diffractive optical element is attached to the chassis via the holding member, complication of the configuration becomes a problem.

  On the other hand, Patent Document 2 proposes a laser scanning optical device that can correct skew and bow of a scanning line with a simple configuration. In the laser scanning optical device, the position of the lens is adjusted by pushing out the lens with an adjusting screw provided in the adjusting means. Therefore, in the laser scanning optical device, unlike the scanning optical device described in Patent Document 1, a holding member or the like that rotatably holds the lens is not required, and the configuration can be simplified and downsized.

However, in the laser scanning optical device described in Patent Document 2, the lens can be adjusted only in the sub-scanning direction. For this reason, the laser scanning optical device cannot perform correction when the scanning line is shifted in the main scanning direction.
JP-A-11-326804 JP 2007-114396 A

  Accordingly, an object of the present invention is to provide a scanning optical device capable of adjusting the position of an optical element in the main scanning direction and the sub-scanning direction with a simple configuration.

  According to the present invention, in a scanning optical device that exposes a beam deflected by a deflector onto a surface to be scanned via a scanning optical system comprising optical elements, the optical elements are held on a predetermined plane. A housing, and an adjustment means for adjusting the position by sliding the optical element in a main scanning direction and a sub-scanning direction that are parallel to the plane and perpendicular to each other. Features.

  According to the present invention, the position of the optical element is adjusted by sliding the optical element on a plane in the main scanning direction and the sub-scanning direction. Thus, the structure which slides on a plane is realizable by comparatively simple structure like the adjustment part which consists of a bracket and an adjustment screw, for example. As a result, it is possible to provide a scanning optical device capable of adjusting the position of the optical element in the main scanning direction and the sub-scanning direction with a simple configuration.

  Hereinafter, a scanning optical device according to an embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a sectional structural view of a scanning optical device 1 according to an embodiment of the present invention. FIG. 2 is an external perspective view of the second housing portion 35 of the scanning optical device 1. 1 and 2, the y-axis direction indicates the main scanning direction, and the x-axis direction indicates the sub-scanning direction perpendicular to the main scanning direction. The z-axis direction is the height direction.

  As shown in FIG. 1, the scanning optical device 1 is configured for image exposure of a tandem type image forming apparatus using electrophotography, and is arranged in parallel with four photosensitive drums 10Y, 10M, 10C, and 10K (hereinafter referred to as “photosensitive”). The body drums are collectively referred to as the photosensitive drums 10). The beams BY, BM, BC, and BK are scanned.

  Known image forming elements such as a charging device, a developing device, and a transfer device are arranged around each photosensitive drum 10, and are configured as four image forming units. An image (electrostatic latent image) formed on each photosensitive drum 10 by beam scanning is developed with yellow, magenta, cyan, and black toners, and is primarily transferred / combined on an intermediate transfer member (not shown). Further, secondary transfer is performed on the transfer material. This type of tandem image forming process is well known and will not be described.

  The scanning optical device 1 includes a light source unit (not shown), a polygon mirror 5 and a scanning optical system 20. The light source unit consists of four laser diodes and emits a beam. The polygon mirror 5 functions as a deflector that deflects the beam emitted from the light source unit. The scanning optical system 20 forms an optical path from the polygon mirror 5 to each photosensitive drum 10. The light source unit, the polygon mirror 5 and the scanning optical system 20 are held in a housing 30.

  The scanning optical system 20 includes a first lens 21, plane mirrors 23Y, 23M, 23C, 23K, 24Y, 24M, and 24C (hereinafter, the plane mirrors are collectively referred to as plane mirrors 23 and 24) and the first. 2 lenses 22Y, 22M, 22C, and 22K (hereinafter, the second lens is collectively referred to as the second lens 22). The first lens 21 is a scanning lens common to the four optical paths. The second lens 22 is a long scanning lens that is located at the terminal end of the scanning optical system 20 and is individually disposed in the four optical paths. The second lens 22 is arranged so as to be aligned in the x-axis direction, and the longitudinal direction of the second lens 22 is arranged so as to coincide with the y-axis direction as shown in FIG.

  The light source unit emits a beam having a predetermined angle in the z-axis direction with respect to the polygon mirror 5, and the beam is deflected at a constant angular velocity in the y-axis direction based on the rotation of the polygon mirror 5. In FIG. 1, BY, BM, BC, and BK indicate beams deflected by the polygon mirror 5. The first lens 21 and the second lens 22 have a function of giving fθ characteristics to each beam and correcting aberration.

  The beam BY passes through the first lens 21, is reflected by the plane mirrors 23Y and 24Y, passes through the second lens 22Y, and exposes the photosensitive drum 10Y. The beam BM passes through the first lens 21, is reflected by the plane mirrors 23M and 24M, passes through the second lens 22M, and exposes the photosensitive drum 10M. The beam BC passes through the first lens 21, is reflected by the plane mirrors 23C and 24C, passes through the second lens 22C, and exposes the photosensitive drum 10C. The beam BK passes through the first lens 21, is reflected by the plane mirror 23K, passes through the second lens 22K, and exposes the photosensitive drum 10K.

  The housing 30 is roughly divided into two parts, a first housing portion 31 and a second housing portion 35. The second housing portion 35 is formed with an opening 36 through which each beam BY, BM, BC, BK passes. The first housing portion 31 holds the polygon mirror 5 including the motor 6, the first lens 21, and the plane mirrors 23Y, 23M, 23C, 23K, 24Y, 24M, and 24C. The second casing portion 35 is made of the same material as that of the first casing portion 31 and is disposed closer to the photosensitive drum 10 (scanned surface) than the first casing portion 31. Yes. Further, the second casing portion 35 is exposed on the photosensitive drum 10 side, and is on a plane SY, SM, SC, SK (hereinafter, the plane is collectively referred to as the plane S). The second lenses 22Y, 22M, 22C, and 22K are held. The plane S is parallel to the x-axis direction and the y-axis direction.

  As shown in FIGS. 1 and 2, the second housing portion 35 is provided with an adjustment mechanism 39 so as to correspond to each second lens 22. The adjustment mechanism 39 is a member for adjusting the position by sliding the second lenses 22 in the x-axis direction and the y-axis direction on the plane S. The adjustment unit 39 includes the adjustment unit 40, the leaf springs 43 a and 43 b, and the support member 44. It is configured.

  The adjustment unit 40 includes a bracket 41 and an adjustment screw 42, and is exposed to the outside of the second housing portion 35 so as to face the photosensitive drum 10, as shown in FIG. The bracket 41 is configured by bending a metal plate and is fixed to the second casing portion 35. The adjustment screw 42 is screwed into a hole provided in the bracket 41. The adjustment unit 40 is provided in each second lens 22 so as to come into contact with the second lens 22 from the positive direction side in the x-axis direction in the vicinity of the central portion in the y-axis direction and the end portion in the positive direction in FIG. Yes.

  The support member 44 is provided in each second lens 22 so as to come into contact with the second lens 22 from the positive side in the x-axis direction in the vicinity of the end in the negative direction in the y-axis direction of FIG. The leaf springs 43a and 43b are opposed to the support member 44 and the adjustment unit 40 with the second lens 22 interposed therebetween. More specifically, the leaf spring 43a is provided in the second lens 22 in the vicinity of the center portion in the y-axis direction and the end portion in the negative direction in FIG. It is an elastic member that biases each second lens 22 in the positive direction. Further, the leaf spring 43b is provided in the vicinity of the positive end portion in the y-axis direction of FIG. 2 in each second lens 22 and on the negative direction side in the x-axis direction, and in the positive direction in the x-axis direction. An elastic member that biases the second lens 22. Thus, the second lens 22 is sandwiched and fixed by the adjustment screw 42, the support member 44, and the leaf springs 43a and 43b. In FIG. 2, the second lens 22 </ b> K is not provided with the adjustment unit 40 and cannot be adjusted in position. Therefore, as shown in FIG. 2, a support member 44 is provided instead of the adjustment unit 40.

  The position adjustment of the second lens 22 by the adjusting mechanism 39 is performed by bending the scanning line on the photosensitive drum 10 by each beam as shown in the plan view of the second housing portion 35 shown in FIG. This is performed to correct the inclination (skew) of the main scanning line with respect to the main scanning direction or the shift of the center position of the scanning line (partial magnification). More specifically, when adjusting the bow, as shown in the second lens 22C of FIG. 3, the adjustment screw 42 arranged at the center portion is screwed to push out the center portion of the second lens 22C in the x-axis direction. Then, the second lens 22C is bent in a bow shape. At the time of skew adjustment, as shown in the second lens 22M of FIG. 3, the adjustment screw 42 arranged near the end on the positive direction side in the y-axis direction is screwed in so that the end on the negative direction side in the y-axis direction is The second lens 22M is rotated around the z-axis (around the optical axis of the second lens 22M) as the center.

  Further, when adjusting the partial magnification, by loosening the adjustment screw 42, the second lens 22Y is translated in the y-axis direction as shown by the second lens 22Y in FIG. At this time, as shown in FIGS. 2 and 3, the reference portion 46 provided at the end of the second lens 22Y on the negative side in the y-axis direction is used as a positioning member for movement in the y-axis direction. More specifically, the position of the reference portion 46 is regarded as the position of the second lens 22Y, and the position of the reference portion 46 is adjusted to adjust the position of the second lens 22Y.

  As described above, in the scanning optical device 1, the position of the second lens 22 is adjusted by sliding the second lens 22 on the plane S in the x-axis direction and the y-axis direction. As described above, the configuration for sliding on the plane S can be realized by a relatively simple configuration such as the adjustment unit 40 including the bracket 41 and the adjustment screw 42. As a result, it is possible to provide the scanning optical device 1 that can adjust the position of the second lens 22 in the main scanning direction and the sub-scanning direction with a simple configuration.

  In the scanning optical device 1, the adjustment unit 40 used when adjusting the bow and the adjustment unit 40 used when adjusting the skew are in contact with the second lens 22 from the same direction. Accordingly, the directions in which the two adjustment units 40 push out the second lens 22 are the same. As a result, each of the bow adjustment and the skew adjustment is reduced from adversely affecting the other adjustment.

  In the scanning optical apparatus 1, the center of rotation of the second lens 22 at the time of adjusting the skew and the reference portion 46 used at the time of adjusting the partial magnification are also located at the end on the negative direction side in the y-axis direction. is doing. Therefore, even if the second lens 22 rotates during skew adjustment, the position of the reference portion 46 hardly changes. Therefore, in the scanning optical device 1, it is possible to accurately adjust the partial magnification even after adjusting the skew.

  In the scanning optical device 1, the adjustment mechanism 39 of the second lens 22 is exposed to the outside from the first housing portion 31 and the second housing portion 35. Therefore, the position of the second lens 22 can be adjusted even after the second housing portion 35 is attached to the first housing portion 31.

  Also, since the first casing portion 31 and the second casing portion 35 are made of the same material, the linear expansion coefficients due to these heats become the same, and the first casing portion 31 and the second casing portion. The distortion of 35 is reduced.

  The second housing part 35 is directly attached to the first housing part 31. Therefore, the mounting accuracy of the second housing portion 35 with respect to the first housing portion 31 is improved as compared with the case where another member is interposed between them.

  Further, since the second lens 22 is a long lens having a longitudinal direction in the y-axis direction, the second lens 22 is not easily damaged even if it is deformed so as to bend during bow adjustment.

  In the scanning optical device 1, the housing 30 is composed of two housing portions, the first housing portion 31 and the second housing portion 35, but is composed of one housing portion. It may be.

  The adjustment mechanism 39 includes the bracket 41 and the adjustment screw 42, but a cam or the like may be used instead of the adjustment screw 42, for example.

1 is a cross-sectional structure diagram of a scanning optical device according to an embodiment of the present invention. It is an external appearance perspective view of the 2nd housing | casing part of the scanning optical apparatus shown in FIG. It is a top view of the 2nd housing | casing part shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Scanning optical device 5 Polygon mirror 10Y, 10M, 10C, 10K Photosensitive drum 20 Scanning optical system 21 First lens 22Y, 22M, 22C, 22K Second lens 30 Housing 31 First housing portion 35 Second housing Body part 39 Adjustment mechanism 40 Adjustment part 41 Bracket 42 Adjustment screw 46 Reference part

Claims (10)

In a scanning optical device that exposes a beam deflected by a deflector onto a surface to be scanned through a scanning optical system composed of optical elements,
A housing holding the optical element on a predetermined plane;
Adjusting means for adjusting the position by sliding the optical element in a main scanning direction and a sub-scanning direction that are parallel to the plane and perpendicular to each other;
Having
A scanning optical device. The adjusting unit corrects the inclination of the scanning line on the scanned surface with respect to the main scanning direction, the curvature of the scanning line on the scanned surface, and the shift of the center position of the scanning line on the scanned surface. ,
The scanning optical apparatus according to claim 1. The adjusting means performs position adjustment by moving the optical element in a main scanning direction;
The scanning optical apparatus according to claim 2. The adjusting means performs position adjustment by rotating the optical element around an optical axis;
The scanning optical device according to claim 2, wherein The adjusting means bends the optical element to adjust the position;
The scanning optical device according to claim 2, wherein the scanning optical device is a scanning optical device. The adjusting means performs position adjustment by rotating the optical element around the optical axis, and performs position adjustment by moving the optical element in the main scanning direction,
The center of rotation about the optical axis of the optical element is the first end of the optical element;
The optical element has a positioning member in movement in the main scanning direction on the first end side;
The scanning optical apparatus according to claim 2. The optical element is a long lens provided so that a longitudinal direction thereof coincides with the main scanning direction,
The adjusting means includes
A first support member provided to contact the first end of the long lens;
First adjusting means provided so as to come into contact with a longitudinal central portion of the long lens;
A second adjusting means provided so as to contact the second end of the long lens;
A second support member, a third support member, and a fourth support member that face each of the first adjustment unit, the second adjustment unit, and the first support member with the optical element interposed therebetween. When,
Including
The scanning optical device according to claim 1, wherein When correcting the inclination of the scanning line on the scanned surface with respect to the main scanning direction, the second adjustment unit rotates the long lens,
When correcting the curvature of the scanning line on the surface to be scanned, the first adjusting means bends the long lens;
The scanning optical apparatus according to claim 7. A plurality of the optical elements are provided;
9. A scanning optical device according to claim 1, wherein The adjusting means is provided so as to be exposed to the outside of the housing;
The scanning optical device according to claim 1, wherein

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