JPH0894913A - Optical scanner - Google Patents

Abstract

PURPOSE: To provide an optical scanner whose structure is simple without using a spring and which is provided with the adjustment device of a mirror which is easily adjusted. CONSTITUTION: The optical scanner is provided with the adjustment means adjusting the inclination of a scanning line by rotating the cylindrical mirror 7 arranged in the middle of an optical path and the cylindrical shaft of the mirror 7. The adjustment means is provided with a supporting means supporting the mirror 7 so that the cylindrical surface thereof is made to abut on three reference pins, a turnable turning member 10 which supports one side surface near one end of the mirror 7 in a longitudinal direction by a fixed pin 9 and whose surfaces abutting on the mirror 7 and being the opposite side thereof are a spherical surface or the surface of curvature and a supporting means consisting of a screw 4 being a pressing means pressing the turning member 10 to the other side surface near one end of the mirror 7. Besides, it is provided with a side surface supporting means supporting both side surfaces near the other end of the mirror 7 by a supporting point whose position can be adjusted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mirror adjusting device for adjusting the position of a light beam on a surface to be scanned in an optical scanning device such as a digital copying machine or a printer.

[0002]

2. Description of the Related Art Conventionally, many optical scanning devices having a structure for adjusting the attitude of a mirror immediately before a scanning surface have been proposed in order to finally position a scanning position. Japanese Patent Publication 62-23
Japanese Patent No. 844 describes a structure in which a mirror is supported by three-point plungers. However, in such a structure, if one plunger is adjusted, at least two or more parameters of the direction horizontal to the drum axis, the direction vertical to the axis, and the optical path length change at the same time, which makes adjustment work difficult and the plunger is difficult to adjust. Supported by springs,
Considering the distortion, the force for pressing the mirror cannot be increased to a certain extent or more, so that the position is likely to be displaced due to vibration, impact, or the like. This is more noticeable when the mirror is large and heavy.

Japanese Patent Publication No. 2-338927 does not show a specific structure, but the mirror has a first rotation axis that intersects the optical axis in the mirror plane and is parallel to the main scanning direction, and the mirror. There is described a configuration in which the second rotation shaft intersects the optical axis in the plane and is rotatably supported by the second rotation shaft perpendicular to the first rotation shaft. With such a configuration, adjustment of the paper feed direction and tilt adjustment (skew adjustment) with respect to the drum axis can be performed by rotating each axis, but a large and heavy mirror is centered on an axis perpendicular to the drum axis. Providing a rotating shaft structure complicates the mechanism and is disadvantageous in terms of cost. In Japanese Patent Publication No. 22928/1990, a shaft for rotating a mirror is provided to adjust the tilt in the main scanning direction, and one end is supported by a spring and a movable support point. Also in this configuration, providing a shaft structure with high precision for rotating a large and heavy mirror also complicates the mechanism and is disadvantageous in terms of cost. Further, the support by the spring is apt to be displaced due to vibration, impact or the like.

As an improvement plan of the above conventional example, FIG.
There has been proposed a support adjustment structure for a mirror as shown in FIG.
This mirror support adjustment structure supports the cylinder surface of a cylinder mirror 7 having a reflecting surface having the shape of a cylinder surface by three reference pins 3-1, 3-2, 3-3,
By pressing from the back with a spring etc. during adjustment,
The three supporting points are supported so that the cylinder surface can move while abutting, and the screws 31, 32, 33, 3 which are supporting points whose positions can be adjusted are provided on the side surfaces of the four corners.
4 is provided. Moreover, a pin for passing the cylinder surface and rotating the mirror about an axis parallel to the cylinder axis is provided on the outside of the side plate 1, and this pin is fitted to a frame (not shown). This mirror support mechanism, by adjusting the support points with screws at the four corners,
Skew adjustment is performed by rotating the cylinder surface around an axis perpendicular to the paper surface of FIG. 6, and the structure is simple, and the skew adjustment operation and the position adjustment operation in the sub-scanning direction (paper feed direction) are separated. Therefore, adjustment of one does not shift the other. Also, since no spring is used, it is strong against vibration and shock.

[0005]

In the conventional mirror support structure, it is difficult to adjust by a simple three-point support, and if a shaft structure in a direction perpendicular to the cylinder surface is provided, the mechanism becomes complicated and expensive. There is a problem in that it is susceptible to vibration and shock when supported by a spring. Further, in the mirror support adjusting device as shown in FIG. 6, when the adjustment is performed, the adjusting screws 31, 3 at one end are used.
Even if the mirror is adjusted only by 2, the mirror will be distorted if the adjustment screws 33, 34 at the other end are tightened. Therefore, it is necessary to loosen the screws at both ends for adjustment. Therefore, even if adjustment is performed while looking at the scanning surface, when the screws at both ends are finally tightened, the positions are displaced, and it is necessary to repeat the adjustment again. SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the prior art and to provide an optical scanning device having a mirror adjusting device which has a simple structure without using a spring or a shaft structure and which can be easily adjusted. .

[0006]

According to the present invention, in an optical scanning device having a cylinder mirror and adjusting means for adjusting the posture of the cylinder mirror, the adjusting means has at least a surface contacting the cylinder mirror having a spherical surface or a curved surface. It is characterized by including side surface supporting means for supporting one side surface of one end of the cylinder mirror by any one of the rotating members.

[0007]

In the present invention, one side surface of one end of the mirror is supported by the rotatable member. Therefore, when the position of the other end is changed, the rotating member rotates to cause the mirror to move. It is possible to prevent stress exerting an adverse effect such as distortion from being applied, and since the end portion on the rotating member side can be adjusted while being tightened, it is not necessary to perform the adjustment again. Further, since the shaft structure is not used, the structure is simple and the vibration resistance and shock resistance are improved.

[0008]

2 is a vertical sectional view of an embodiment of an optical scanning device to which the present invention is applied. A frame 20 made of aluminum or the like is provided with an optical casing 21 made of resin or the like, on which an fo lens 16 and the like are mounted, and a polygon scanner 19 having a polygon mirror 15. Frame 20
The mirrors 17 and 18 and the cylinder mirror 7 relating to the present invention are attached to the side surface of the sheet. By rotating the cylinder mirror 7 and its entire supporting member around an axis passing through the cylinder surface, the sheet feeding on the photosensitive drum 11 is performed. It is configured to adjust the positioning in the direction. The light beam output from the laser light source unit (not shown) is deflected in the main scanning direction by the polygon mirror 15, and f
After passing through the o lens 16, the light is reflected by the mirrors 18 and 19 and the cylinder mirror 7, and then focused on the photosensitive drum 11. In addition, 12 is a rotating direction of the drum, 13 is a charger, and 14 is an imaging beam.

FIG. 3 is a plan view of a mirror support adjusting device according to the present invention. The same members as in FIG. 6 are given the same numbers. This mirror support adjusting device has a housing 2 that surrounds the side surface and the back surface of the mirror 7. Then, the cylinder surface of the cylinder mirror 7 having a reflecting surface having the shape of the cylinder surface is provided with three reference pins 3-1.
It is supported by 3-2 and 3-3. Mirror 7 is the third
The side surface of one end is supported by the position adjusting screws 4-2 and 4-3 provided on the housing 2, which is the side surface supporting means, and the other end is the fixing pin 9 which is the first side surface supporting means.
Further, the surface that abuts on the mirror and the surface that faces the mirror, which constitute the second side surface supporting means, are spherical or cylindrical, and are supported by the pin member 10 that is rotatably mounted. The screw 4-1 serving as a pressing unit presses the pin member 10 against the side surface of the mirror 7. A pin 21 is provided on the outside of the side plate 1 for rotating the mirror about an axis passing through the cylinder surface and parallel to the cylinder axis.

FIG. 4 is a sectional view taken along the line MM in FIG. 3 of the mirror support adjusting device according to the present invention, and FIG. 5 is a sectional view taken along the line NN in FIG. At the time of adjustment, the rear surface fixing screws 5-1 and 5-2 provided on the rear surface of the housing 2 surrounding the side surface and the rear surface of the mirror 7 are loosened, and the mirror 7 is pressed from the rear surface by the spring 6 of FIG. Is structured so that the cylinder surface can move and rotate while contacting the three support points. Reference numeral 8 is a screw for fixing the spring to the housing 2. After the adjustment is completed, the screw 5 for fixing the rear surface of FIG.
The mirror 7 is fixed by tightening -2.

FIG. 1 is an enlarged view of the lower mirror support structure of FIG. The pin member 10 is, for example, a metal pin whose both ends are processed into a spherical shape, and the diameter of the sphere is, for example, equal to the length of the pin 10, that is, the sphere cut into a cylindrical shape can be used. The bottom surface of the screw 4-1 for pressing and fixing the pin member 10 to the mirror 7 is processed into a flat shape. Also,
The shape of the tip of the fixing pin 9 that faces the pin member 10 and supports the side surface on the opposite side is also spherical, and the fixing pin 9 may be simply inserted into the hole of the housing, or fixed by any means. It may have been done.

When adjusting the cylinder mirror support adjusting device of the optical scanning device of the present invention, it is not necessary to open both ends of the mirror as in the conventional example shown in FIG. The fixed pin 9 and the pin member 10 which is the rotating member may remain clamped with the screws 4-1 at an appropriate strength. Then, the adjustment screw 4- on the upper side of FIG.
By adjusting 2 and 4-3, the mirror 7 rotates about the fixed pin 9 which is a substantially fixed support point. Then, as the mirror 7 rotates, the rotating pin 10 moves the mirror 7
And the bottom surface of the fixing screw 4-1 to rotate to reduce the stress applied to the mirror 7. Now, the displacements dx and dy at the contact point P between the pin member 10 and the mirror 7 when the mirror 7 is tilted in the direction indicated by the alternate long and short dash line in FIG. Mirror 7 at the end of adjusting screws 4-2 and 4-3 side in FIG.
Is C, the length of the mirror 7 is L, the width is W, and the rotation angle is dθ, the following expression 1 is established.

Tan (dθ) = C / L Equation 1

Therefore, dy is approximately obtained by the following equation 2.

Dy = W · tan (dθ) = W · C / L Formula 2

Further, dx is approximately obtained by the following equation 3.

Dx = dy · tan (dθ) = dy · C / L Formula 3

Assuming that the length L of the mirror 7 in the actual device is, for example, 600 mm, the width W is 20 mm, and the movement amount C is 2 mm, substituting these values into the equations 2 and 3, dy is about 0. 07mm, dx is about 0.0002mm
That is, it becomes 0.2 μm. Therefore, the pin member 10 is the mirror 7
It suffices if the end of the pin that comes into contact with is rolled by about 0.07 mm. However, when the pin member 10 is in contact with the hole provided in the housing 2, the pin member 10 cannot rotate any more. Therefore, when the pin member 10 is separated from the side surface of the surrounding hole by the maximum movement distance of the pin or more. Need to assemble. The displacement dx in the x direction is only 0.2 μm, which is a negligible value.
Therefore, even if the mirror is tilted while the screw 4-1 is tightened, the mirror 7 can be adjusted without being distorted.

Although the embodiments have been described above, the present invention may be modified as follows. The shape of the pin member 10 does not need to be a pin and may be a sphere. The diameter of the spherical surface does not have to match the length of the pin. If a spherical surface having a diameter different from the diameter of the pin is adopted, the fixed pin and the bottom surface of the screw that presses the movable pin member when the mirror is tilted are used. It is also possible to keep the distance constant and the clamping force unchanged. The same effect can be obtained by processing the bottom surface of the screw into a curved surface. The ends of the movable pin and the fixed pin may have a spherical shape, or a cross section parallel to the mirror surface of the mirror 7 may have an end shape such as a semicircle, a trapezoid, or a triangle, and the shape of the contact surface with the mirror 7. The shape may be a dot, a circle, a straight line, a rectangle, or the like. In order to assemble the pin member so that it does not come into contact with the surroundings, a member such as a soft sponge may be wrapped around the pin and then inserted into the hole. As the third side surface supporting means, any method other than the method of supporting both side surfaces with screws can be adopted.

[0020]

As described above, according to the present invention,
Since one side surface of one end of the mirror is supported by a rotatable member, when the position of the other end is changed for adjustment, the rotating member rotates, which may adversely affect the mirror such as distortion. The applied stress can be prevented. Therefore, there is an effect that the end portion on the side of the rotating member can be adjusted while being tightened, and it is not necessary to redo the adjustment. Furthermore, since the shaft structure etc. is not used, the structure is simple, and after adjustment it is not supported by springs etc.
Since it is firmly fixed with screws, it also has the effect of improving vibration resistance and shock resistance.

[Brief description of drawings]

FIG. 1 is an enlarged view of a lower mirror support structure of FIG.

FIG. 2 is a vertical sectional view of an embodiment of an optical scanning device to which the present invention is applied.

FIG. 3 is a plan view of a mirror support adjusting device according to the present invention.

FIG. 4 is a sectional view taken along the line MM of the mirror support adjustment device according to the present invention.

FIG. 5 is a sectional view of the mirror support adjusting device according to the present invention taken along the line NN.

FIG. 6 is a plan view of a conventional mirror support adjusting device.

[Explanation of symbols]

1 ... Side plate, 2 ... Housing, 3 ... Reference pin, 4 ... Adjusting screw, 5 ... Rear fixing screw, 6 ... Leaf spring, 7 ... Cylinder mirror, 8 ... Screw, 9 ... Fixing pin, 10 ... Pin member

Claims (1)

[Claims] 1. An optical scanning device having a cylinder mirror and adjusting means for adjusting the posture of the cylinder mirror, wherein the adjusting means is a rotating member having at least a surface abutting on the cylinder mirror which is a spherical surface or a curved surface. An optical scanning device comprising a side surface supporting means for supporting one side surface of one end of a cylinder mirror.