KR100580201B1 - Mirror positioning apparatus of laser scanning unit - Google Patents

Abstract

The present invention discloses an apparatus for adjusting the position of the reflector capable of easily adjusting the rotation angle and the linear movement amount of the reflecting mirror for scanning inclination and scanning curvature correction. According to one type of the present invention, in the reflector position adjusting device mounted on the frame of the optical scanning device to adjust the reflector rotation angle and linear movement amount of the optical scanning device, a groove for inserting and fixing the reflecting mirror is formed on one surface thereof. A reflector fixing member in which a rotating shaft having a tapered end portion having a predetermined curvature protrudes perpendicular to the other surface; And a reflector position fixing member having an opening engaged with an end of the rotating shaft of the reflector fixing member, the reflector position fixing member having an inner diameter of the opening having a curvature equal to the curvature formed at the end of the rotating shaft. Is coupled to the reflector position fixing member attached to the outer frame through the frame.

Description

Mirror positioning apparatus for adjusting the scanning tilt and scanning curvature

1A and 1B show a conventional optical scanning device and a reflector structure.

Figure 2 shows a conventional structure for adjusting and fixing the tilt of the reflector.

Figure 3 shows the scanning inclination and the scanning curve generated in the optical scanning device in the form of a graph.

Figure 4 shows a reflector fixing member of the reflector position adjusting apparatus according to the present invention.

5 shows a reflector position fixing member of the reflector position adjusting device according to the present invention.

6 shows an assembled state of the reflector position adjusting device according to the present invention.

7A to 7C show the operation of the reflector position adjusting device according to the present invention.

8 shows a reflector position guide member of the reflector position adjusting device according to the present invention.

9 shows an assembled state of the reflector position adjusting device including the reflector position guide member.

10A to 10C show the operation of the reflector position adjusting device including the reflector position guide member.

11 is a view illustrating a scan slope and a scan curvature correcting operation by adjusting a rotation and a position of a reflector in the optical scanning apparatus according to the present invention.

※ Explanation of code about main part of drawing ※

10 ..... reflector fixing member 20 ..... reflector position fixing member

30 ..... Reflector position guide member

50 ..... reflector

The present invention relates to an apparatus for adjusting the position of a reflector for scanning inclination and scanning curvature correction, and more particularly, to an apparatus for adjusting the position of a reflector for easily adjusting the rotation angle and linear movement amount of a reflecting mirror for scanning inclination and scanning curvature correction. It is about.

Background Art In general, a laser printer is a printing apparatus that forms an image while scanning laser light emitted from a laser diode on a photosensitive member, and reproduces an image image by transferring a latent image formed on the photosensitive member onto a medium such as paper. Gwangju presidential device is an image forming apparatus that generates a laser light in such a laser printer to form an image on a photosensitive member. 1A and 1B schematically illustrate a typical Gwangju presidential device. As shown in FIGS. 1A and 1B, the optical scanning apparatus 100 generally includes a light source 111, a collimating lens 112, an aperture diaphragm 113, a cylinder lens 114, and a polygon mirror 115. ), A scanning lens 116, a reflecting mirror 117, a photosensitive drum 118, and the like. In this case, the light source 111, the collimating lens 112, the aperture stop 113, the cylinder lens 114, the polygon mirror 115, the scanning lens 116 and the reflector 117 is dust generated inside the printer In order to prevent contamination due to the like is installed in a separate frame (110).

In such a structure, the light beam emitted from the light source 111 such as a laser diode is converted into a parallel beam with respect to the optical axis by the collimating lens 112. After the parallel beam is restricted by the aperture stop 113, the parallel beam passes through the cylinder lens 114 and converges in the sub scanning direction to become linear light in a horizontal direction with respect to the sub scanning direction. Thereafter, the horizontal linear light is moved at a constant velocity in the main scanning direction (ie, the horizontal direction of the paper) by the polygon mirror 115 rotating at a high speed while the scanning lens 116 and the reflecting mirror 117 are moved. It forms on the photosensitive drum 118 via. Here, the scanning lens 116 has a constant refractive index with respect to the optical axis, and functions to focus the light on the photosensitive drum 118 by polarizing light having a constant velocity reflected by the polygon mirror 115 in the main scanning direction.

In the optical scanning device 100, the light beam passing through the scanning lens 116 should be scanned on a scan surface such as the photosensitive drum 118 in a straight line along the main scanning direction. However, due to assembly tolerances and aberrations, as shown in FIG. 3, the light beam is finely deviated in the sub-scanning direction and does not scan in a straight line along the main scanning direction of the scan surface. In FIG. 3, a phenomenon in which the heights X ₁ and X ₂ of both ends A and B of the trajectory of the beam spot of the beam spot are different in the sub-scanning direction is called a skew, and the scan line does not become a straight line. The phenomenon of bending is called a bow. Such scanning inclination and scanning curvature lower the printing accuracy and lower the image quality. In particular, in the case of a tandem optical scanning device used in a color laser printer or the like, scanning inclination and scanning curvature are a big problem. In the case of a color laser printer using a tandem type optical scanning device, the scan line curvature on each photosensitive drum is formed differently, and color reproducibility is greatly reduced. The reflector 117 serves to correct the scanning inclination and the scanning curvature by appropriately adjusting the incident angle of the light beam.

2 exemplarily illustrates a conventional structure for adjusting the inclination of the reflector 117. As shown in FIG. 2, in the conventional case, the groove 125 is formed in the frame 110, and the lower end portion of the reflector 117 is inclined to the groove 125. The screw 122 is installed at a position on the frame 110 corresponding to the upper end of the reflector 117. Thereafter, the screw 122 is rotated to appropriately adjust the insertion depth of the screw 122, thereby adjusting the angle of the reflector 117. Then, the reflector 117 is firmly fixed using the leaf spring 120.

In the related art, by adjusting the angle of the reflector, the angle of the beam scanned by the photosensitive drum is changed to correct the scanning distortion of the beam. However, in order to correct the distortion more efficiently, not only the angle of the beam scanned by the photosensitive drum should be aligned by adjusting the rotation angle of the reflector between the scanning lens and the photosensitive drum, but also the beam incident on the scanning lens at the same time. The inclination position of the beam must be corrected by adjusting the incidence position of the beam so that the scanning slope and the scanning curvature can be corrected simultaneously. Therefore, there is a need for a new technology capable of simultaneously adjusting the incident angle and the incident position of the scanning beam, rather than the conventional technique of correcting the scanning distortion phenomenon by only adjusting the rotation angle of the reflector. There is also a need for a complementary technique that allows for more robust attachment of reflectors.

The present invention is directed to improving the above-mentioned conventional problem. Accordingly, it is an object of the present invention to provide a reflector position adjusting device capable of easily adjusting the rotation angle and the linear movement amount of the reflector and a photo-preservation device employing the same.

It is also an object of the present invention to improve the quality of color print images by mechanically correcting the scanning inclination and the scanning curvature phenomena caused by the alignment error of the laser beam in the tandem optical scanning device.

According to one type of the present invention, in the reflector position adjusting device mounted on the frame of the optical scanning device to adjust the reflector rotation angle and linear movement amount of the optical scanning device, a groove for inserting and fixing the reflecting mirror is formed on one surface thereof. A reflector fixing member in which a rotating shaft having a tapered end portion having a predetermined curvature protrudes perpendicular to the other surface; And a reflector position fixing member having an opening engaged with an end of the rotating shaft of the reflector fixing member, the reflector position fixing member having an inner diameter of the opening having a curvature equal to the curvature formed at the end of the rotating shaft. The penetrating penetrates the frame and is coupled to the reflector position fixing member attached to an outer frame.

At this time, the curvature formed at the end of the rotating shaft of the reflector fixing member and the curvature formed in the opening of the reflector position fixing member may be a hemispherical curvature, or may be a conical curvature. Then, the end of the rotating shaft of the reflector fixing member having a curvature and the inner diameter of the opening of the reflector position fixing member are surface-treated to prevent slippage.

In addition, a cylindrical bar having a diameter smaller than the diameter of the rotating shaft may be protruded from an end of the rotating shaft of the reflector fixing member.

The reflector position adjusting device according to the present invention is attached to the frame by penetrating the frame between the reflector fixing member and the reflector position fixing member, and an opening is formed therein so that the rotating shaft of the reflector fixing member can penetrate. It may further include a reflector position guide member, wherein the opening of the position guide member is characterized in that the form of a long hole for adjusting the linear movement amount of the reflector fixing member.

Hereinafter, with reference to the accompanying drawings, the configuration and operation of the reflector position adjusting apparatus according to an embodiment of the present invention will be described in detail.

Figure 4 shows a reflector fixing member of the reflector position adjusting device according to the present invention, which is a front view, a side view, and a rear view in order from the left. As shown in Figure 4, the front surface of the reflector fixing member 10 of the reflector position adjusting device according to the present invention, the rotating shaft 12 is formed to protrude vertically, the rear of the insertion groove 11 for inserting and holding the reflector ) Is formed. When the reflector fixing member 10 rotates about the rotation shaft 12, a reflector (not shown) inserted into the insertion groove 11 rotates to adjust the angle of the reflector. At the end of the rotating shaft 12, a curvature portion 13 that is thinned to have a predetermined curvature is formed. For example, the curvature 13 may have a hemispherical curvature or a conical curvature. In addition, a cylindrical bar 14 having a diameter smaller than the diameter of the rotation shaft 12 protrudes from the curvature 13 formed at the end of the rotation shaft 12. Therefore, when the rotation angle and the linear movement amount of the reflector are adjusted, the cylindrical bar 14 may be grasped to rotate or move the reflector fixing member 10.

Figure 5 shows a reflector position fixing member of the reflector position adjusting device according to the present invention, the center is a front view, the bottom is a bottom view, the right is a side view. As shown in FIG. 5, an opening that engages with the curvature portion 13 formed on the rotation shaft 12 of the reflector fixing member 10 near the center of the reflector position fixing member 20 of the reflector position adjusting device according to the present invention. 21 is formed. At this time, the inner diameter 23 of the opening 21 has the same curvature as the curvature of the curvature 13 so that it can be accurately engaged with the curvature 13 formed at the end of the rotary shaft 12. Then, near each corner of the reflector position fixing member 20, for example, a fastening member (not shown) for fixing the reflector position fixing member 20 to the outer frame 40 (see FIG. 6) of the optical scanning device. The fastener 22 to be inserted is formed. The fastener 22 has a form of a long hole so that the linear movement amount of the reflector position fixing member 20 can be adjusted within a predetermined range.

6 is an assembled state of the reflector position adjusting apparatus according to the present invention. As shown in Figure 6, the reflector fixing member 10 for supporting and rotating the reflector is located inside the optical scanning device. At this time, the rotating shaft 12 of the reflector fixing member 10 passes through the opening 45 formed in the frame 40 to protrude out of the frame 40. As described above, a hemispherical or conical curvature 13 is formed in the cross section of the rotation shaft 12. In addition, a cylindrical bar 14 protruding from the center of the curvature 13 is formed so as to allow axial rotation and horizontal movement manually or automatically. On the other hand, the opening 45 of the frame 40 has a guide surface in the form of a long hole so that the linear movement amount of the reflector fixing member 10 can be adjusted within a predetermined range. That is, the height of the opening 45 is equal to the diameter of the rotating shaft 12, the width is the length of the horizontal movement distance of the reflector fixing member 10 plus the diameter of the rotating shaft 12 plus the necessary tolerances by tilting. .

In this state, after adjusting the scan inclination and the scanning curvature through the axial rotation and the horizontal movement of the reflector rotating member 10, the reflector fixing member 10 is fixed to the adjusted position. To this end, the reflector position fixing member 20 is fixed to the frame 40 in close contact with the reflector fixing member 10 from the outside of the frame 40. The fixing of the reflector position fixing member 20 inserts a fastening member (not shown) into the fastener 22 formed near the edge of the reflector position fixing member 20 and the fastener 42 formed in the frame 40. By doing so. In this case, the cylindrical bar 14 of the reflector fixing member 10 passes through the opening 21 formed in the reflector position fixing member 20, and the curvature 13 of the reflector fixing member 10 is the opening 21. It is engaged with the inner diameter (23) of. Since the inner diameter 23 and the curvature portion 13 of the opening 21 have surfaces with the same curvature, they can be closely adhered to each other accurately.

Since the reflector fixing member 10 and the reflector position fixing member 20 each have the same curvature, the reflector fixing member 10 is oblique to the frame 40 during the axial rotation and the horizontal movement. Even if it is inclined, the reflector position fixing member 20 may be horizontally fixed to the frame 40. Therefore, the reflector fixing member 10 and the reflector position fixing member 20 can be stably fixed to the frame 40 while maintaining the adjusted values of the scan tilt and the scan curvature. After adjusting and fixing the scan inclination and the scan curvature, the curvature 13 of the reflector fixing member 10 is minimized in order to minimize a phenomenon in which the relative positions of the reflector fixing member 10 and the reflector position fixing member 20 are changed by an impact or the like. ) And the inner diameter 23 of the reflector position fixing member 20 can be molded by adjusting the surface roughness. Alternatively, the curvature 13 and the inner diameter 23 may be surface treated to form a non-slip coating on the surfaces of the curvature 13 and the inner diameter 23.

7A to 7C show the operation of the reflector position adjusting device according to the present invention. First, after combining the reflector 50 and the reflector fixing member 10, the reflector fixing member 10 is inserted into the frame 40. Then, in the state in which the reflector position fixing member 20 is fitted to both ends of the reflector fixing member 10, by rotating or moving the reflector fixing member 10 in the horizontal direction, the rotation angle and the linear movement amount of the reflector 50 are changed. Adjust After the rotation angle and the linear movement amount of the reflector 50 are adjusted, the reflector position fixing member 20 fitted to the reflector fixing member 10 is fixed to the frame 40. In this case, as shown in FIG. 7A, the reflector 50 may be positioned at the center of the reference line, may be fixed by moving horizontally from the reference line as shown in FIG. 7B, or may be fixed by being inclined with respect to the reference line as shown in FIG. 7C. As shown in FIG. 7B, when the reflector 50 is fixed by moving horizontally from the reference line, the reflector position fixing member 20 on the left and right sides is fixed to the frame 40 by moving in the same direction. In addition, as shown in FIG. 7C, when the reflector 50 is inclined and fixed with respect to the reference line, the reflector position fixing members 20 on the left and right sides move in opposite directions and are fixed to the frame 40. In any case, due to the curvature surfaces formed on the reflector fixing member 10 and the reflector position fixing member 20, the reflector fixing member 10 and the reflector position fixing are maintained while the adjustment values of the scan tilt and the scan curvature are maintained. The member 20 can be stably fixed to the frame 40.

On the other hand, when it is difficult to precisely mold the guide surface of the reflector fixing member 10 to the frame 40, the reflector position guide member 30 as shown in Figure 8 may be manufactured separately and assembled to the frame 40. As illustrated in FIG. 8, the reflector position guide member 30 according to the present invention has an opening 32 formed therein so that the rotating shaft 12 of the reflector fixing member 10 may be guided in a horizontal direction. It is. The opening 32 of the reflector position guide member 30 has a guide surface in the form of a long hole so that the linear movement amount of the reflector fixing member 10 can be adjusted within a predetermined range. That is, the height of the opening 32 is equal to the diameter of the rotating shaft 12, the width is the length of the horizontal movement distance of the reflector fixing member 10 plus the diameter and the necessary tolerances by tilting the rotating shaft 12. . Fastening holes 33 for fixing the reflector position guide member 30 to the frame 40 are formed at both sides of the opening 32.

9 shows an assembled state of the reflector position adjusting device including the reflector position guide member 30. As shown in FIG. 9, the reflector position guide member 30 is fixed to the frame 40 through the frame 40 between the reflector fixing member 10 and the reflector position fixing member 30. . The rotation shaft 12 of the reflector fixing member 10 protrudes out of the frame 40 through the opening 32 formed in the reflector position guide member 30. In this state, after adjusting the scan tilt and scan curvature through the axial rotation and horizontal movement of the reflector rotating member 10, the reflector fixing member 10 using the reflector position fixing member 20 To the fixed position. That is, it is assembled in the same manner as in FIG. 6 except that a separate reflector position guide member 30 is used without directly forming a guide surface on the frame 40.

10A to 10C show the operation of the reflector position adjusting device including the reflector position guide member 30. It works the same as described in FIGS. 7A-7C except that the reflector position guide member 30 is added. That is, the reflector 50 may be positioned at the center of the reference line as shown in FIG. 10A, may be fixed by moving horizontally from the reference line as shown in FIG. 10B, or may be fixed to the reference line as shown in FIG. 10C. When the reflector 50 is moved horizontally from the reference line and fixed, the reflector position fixing members 20 on the left and right sides move in the same direction and are fixed to the frame 40. In addition, when the reflector 50 is inclined with respect to the reference line and fixed, the reflector position fixing members 20 on the left and right sides are moved in opposite directions to be fixed to the frame 40. As described above, in any case, due to the curvature planes formed on the reflector fixing member 10 and the reflector position fixing member 20, the reflector fixing member 10 is maintained in the state in which the adjustment values of the scan tilt and the scan curvature are maintained as they are. ) And the reflector position fixing member 20 can be stably fixed to the frame 40.

Next, the process of correcting the scanning slope and the scanning curvature in the optical scanning device using the position adjusting device of the reflector according to the present invention having the above-described configuration and operation will be described. As described above, the scan tilt and the scan curvature are mainly caused by the light beams being finely deviated due to assembly tolerances and aberrations. The present invention corrects such scan slope and scan curvature by independently adjusting the rotation angle and position of the reflector. 11 is a case where the position adjusting device of the reflector is located between the polygon mirror 50 and the scanning lens 60. Thus, the reflector 40 is also between the polygon mirror 50 and the scanning lens 60. As shown in FIG. 11, by appropriately rotating the reflector 40, the incident angle at which the light beam deflected by the polygon mirror 50 is incident on the scanning lens 60 is adjusted. When the light beam does not enter the center of the scanning lens 60 accurately, the light beam deflected by the polygon mirror 50 is moved by shifting the position of the reflector 40 using the position adjusting device of the reflecting mirror. The incident position incident on 60) can be adjusted.

Although FIG. 11 shows the case where the position adjusting device of the reflecting mirror is located between the polygon mirror 50 and the scanning lens 60, the reflecting position adjusting device is, for example, the scanning lens 60 and the scanning surface, that is, It may be located between the photosensitive drum 70.

In particular, the present invention mechanically corrects scan tilt and scan curvature phenomena that are difficult to correct circuitally among scan distortion phenomena caused by laser beam alignment in a tandem type multi-scanning apparatus applied to a color laser printer. By doing so, the quality of the color print image can be improved. In addition, according to the present invention, by simply adjusting the angle and position of the reflector at the same time, it is possible to correct the scanning inclination and the scanning curvature phenomenon.

Claims (5)

In the reflector position adjusting device mounted on the frame of the optical scanning device in order to adjust the angle of rotation of the reflector and the linear movement amount of the optical scanning device, A reflector fixing member having a groove for inserting and fixing the reflector, the rotating shaft having a tapered end portion having a predetermined curvature protruding perpendicularly to the other surface; And And an opening formed in engagement with an end of the rotating shaft of the reflector fixing member, wherein the inner diameter of the opening has a curvature equal to the curvature formed at the end of the rotating shaft. And a rotation axis of the reflector fixing member is coupled to the reflector position fixing member attached to an outer portion of the frame through the frame. The method of claim 1, And a curvature formed at an end of the rotating shaft of the reflector fixing member and a curvature formed at an opening of the reflector position fixing member is a hemispherical curvature or a conical curvature. The method according to claim 1 or 2, And a rotating shaft end of the reflector fixing member having a curvature formed therein and an inner diameter of the opening of the reflector position fixing member being surface-treated to prevent slippage. The method of claim 2, And a cylindrical bar having a diameter smaller than the diameter of the rotating shaft from the end of the rotating shaft of the reflector fixing member. The method of claim 2, It is attached to the frame through the frame between the reflector fixing member and the reflector position fixing member, further comprising a reflector position guide member having an opening formed therein so that the rotation axis of the reflector fixing member, And the opening of the position guide member is in the form of a long hole to adjust the linear movement amount of the reflector fixing member.

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