JPH0634903A - Method of adjusting optical scanning device - Google Patents

Abstract

PURPOSE:To easily correct the inclination and the positional deviation of a scanning line with a simple structure by supporting an adjustable mirror which guides scanning laser beam onto a photosensitive drum at three points and independently adjusting the mirror arround the axes connecting the respective two fulcra as a center. CONSTITUTION:The laser beam from a laser diode 1 is collimated by a collimator lens 2 into parallel light converged by a cylindrical lens on a rotary polygon mirror 4, a scan is further made by the rotary polygon mirror 4 and the light diverged again is converged on the photosensitive drum 9 through f-theta lenses 5-7. The three-point supported adjustable mirror 8 which guides the scanning laser beam onto the photosensitive drum 9 is provided and adjusted independently about the axes connecting those two fulcra. Consequently, when the photosensitive drum is scanned with the laser beam, a scanning line 11 (positional deviation) or scanning line 12 (angle deviation) which deviates owing to the machining errors and assembly errors of respective components and a housing can easily be approximated to a desired scanning line 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning optical system. More specifically, the present invention relates to a scanning optical system having a reflector provided with an adjusting unit capable of correcting the inclination and positional deviation of the scanning line on the medium to be scanned.

[0002]

2. Description of the Related Art A conventional apparatus is disclosed in Japanese Patent Laid-Open No. 104915/1982.
It is known that, as described in Japanese Patent Laid-Open Publication No. 2003-242242, the reflector is supported by three elastic bodies, and the three adjusting means corresponding thereto move the reflector to correct the deviation of the scanning line.

Further, as described in Japanese Patent Laid-Open No. 59-147317, a reflector is provided with two fixed rotary shafts which are orthogonal to each other, and the reflector is rotated around these shafts so that the scanning line shifts. It is known to correct

[0004]

[Problems to be Solved by the Invention] JP-A-57-1049
In the reflector adjusting means described in Japanese Patent No. 15, the adjustments of the inclination of the scanning line and the correction of the positional deviation are not independent, and the adjustment work is likely to be complicated and requires skill. The adjusting means of the reflector described in JP-A-59-147317 is easy to adjust, but has a complicated structure.

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical scanning device which can easily correct the inclination and position shift of a scanning line and has a simple structure and is inexpensive.

A further object of the present invention is to provide an optical scanning device which can easily correct the length of a scanning line and has a simple structure and is inexpensive.

[0007]

A light source unit, a deflector for scanning a light beam from the light source unit, and a reflector long in the scanning direction for guiding the light beam scanned by the deflector onto a medium to be scanned. In the optical scanning device, three points A, B and C are set on the reflecting surface of the reflector or on the surface facing the reflecting surface, and the three points are sides B.
C forms a triangle perpendicular to the scanning direction, and the reflector is independently rotated about two straight lines of sides AB and BC, thereby adjusting the inclination of the scanning line and the positional deviation.

[0008]

2 is a view showing the surface of the mirror 8 which faces the reflecting surface. The point 13 corresponding to the point A, the point 14 corresponding to the point B, and the point 15 corresponding to the point C described above are set.
A straight line 18 connecting the points 14, a straight line 19 connecting the points 13 and 15,
There is a straight line 17 connecting points 14 and 15. The straight line 16 is a straight line facing the scanning light flux, and the straight line 17 is orthogonal to the straight line 16.

FIG. 4 is a view showing an embodiment in which a section is taken along the line 17, and FIG. 5 is a view taken in a plane which passes through the point 13 and is perpendicular to the mirror 8. Reference numeral 20 denotes a housing made of cast aluminum or plastic, which is provided with a screw hole, and has a screw 21 and a screw 2.
4 is installed so that it can move back and forth. Leaf spring 22,
The leaf spring 25 is fixed to the housing and applies a pressing force to the mirror 8. The mirror 8 contacts the housing at point 14,
The screw 24 and the screw 21 are in contact with each other at points 13 and 15, respectively. The reflecting surface of the mirror 8 is fixed to one plane in space by these three points. Furthermore, in order to regulate the movement of the mirror 8 on the plane, the points 23 and 26 are in contact with the housing. Therefore, by moving the screw 24 and the screw 21 back and forth respectively, the angle of the mirror 8 with respect to the scanning light beam can be changed within a certain range.

That is, when the screw 24 is moved back and forth, the mirror 8
Rotates about the straight line 17, and the angular deviation of the scanning line can be corrected. Further, when the screw 21 is moved back and forth, the mirror 8 rotates around the straight line 18, and the positional deviation of the scanning line can be corrected. However, this correction of the positional deviation causes a considerable amount of angular deviation. However, if the straight line 18 is sufficiently larger than the straight line 17, the angular deviation is slight, and if the screw 24 is moved back and forth again to correct the angular deviation, the scanning line can be the desired scanning line 10. .
As described above, the positional deviation correction includes the angular deviation, but the angular deviation correction hardly includes the positional deviation, so that the adjustment becomes easy. FIG. 3 is a diagram showing another embodiment of FIG. 2 and shows a special case where the straight line 17 and the straight line 18 are orthogonal to each other. In this case, the positional deviation correction of the scanning line due to the advance / retreat of the screw 21 hardly includes the angular deviation, and the positional deviation correction and the angular deviation correction are independent of each other.
Therefore, the adjustment becomes easier.

FIG. 6 is a diagram showing another embodiment of FIG.
In this case, the mirror 8 has three screws 21, a screw 24, and a screw 2.
It is fixed to one plane in space by 7, and the mirror 8 is moved in parallel by advancing and retracting these three screws in the same direction. Therefore, the distance from the rotary polygon mirror 4 to the photosensitive drum 9 changes, and the correction of the length of the scanning line 10 can be adjusted.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing an embodiment of the present invention.
A laser diode 1 which is a light source unit, a collimator lens 2 which collimates laser light diffused from the light source unit,
A cylindrical lens 3 for converging parallel light by a rotary polygon mirror 4 which is a deflector, and a laser beam which is scanned by the rotary polygon mirror 4 and diffused again is focused and scanned on a photosensitive drum 9 which is a medium to be scanned. It is composed of f-θ lenses 5, 6 and 7 for keeping the speed constant, and an adjustable mirror 8 for guiding the scanned laser beam onto the photosensitive drum 9 which is a feature of the present invention.

When scanning with laser light, the photosensitive drum 9
With respect to the desired scanning line 10 above, there are scanning lines 11 which are referred to as “positional deviation” and which are displaced in parallel, and scanning lines 12 which are deviated at an angle referred to as “angle deviation”. As a cause of the deviation, there are processing errors and assembling errors of each part and the case, and it takes a great deal of effort to eliminate them, and the current processing technology is almost impossible in terms of cost.

That is, taking a laser printer as an example, when writing on a sheet on which a format is printed in advance, there is a problem that the format deviates. Therefore, an adjustment work for correcting the deviation of the scanning line must be performed. . Therefore, it is necessary to bring the displaced scanning line 11 or scanning line 12 closer to the desired scanning line 10 by adjusting the rotation of the mirror 8, which is a feature of the present invention.

[0015]

According to the present invention, the reflector is independently rotated around two sides of a triangle formed by three points set on one surface of the reflector, and the inclination and position of the scanning line are adjusted. Since the adjustment of the deviation correction can be performed, the adjustment operation becomes extremely easy.
Further, the adjustment mechanism can be greatly simplified, and an inexpensive optical scanning device can be obtained.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an optical scanning device according to the present invention.

FIG. 2 is a principle diagram showing a surface of a reflector that faces a reflecting surface.

FIG. 3 is a principle view showing a surface of a reflector that faces a reflecting surface.

FIG. 4 is a sectional view of the reflector taken along a plane including a straight line 17 and perpendicular to the reflector.

5 is a cross-sectional view of the reflector taken along a plane passing through a point 13 and perpendicular to the reflector. FIG.

FIG. 6 is a cross-sectional view of the reflector taken along a plane including a straight line 17 and perpendicular to the reflector.

[Explanation of symbols]

1 is a laser diode, 4 is a rotating polygon mirror, 5, 6 and 7 are f
A-? Lens, 8 is a reflector, 9 is a medium to be scanned, 20 is a housing, 21, 24 and 27 are screws, and 22 and 25 are leaf springs.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takahiro Kikuchi 1060 Takeda, Katsuta City, Ibaraki Prefecture Hitachi Koki Co., Ltd.

Claims (2)

[Claims] 1. An optical scanning device comprising a light source section, a deflector for scanning a light beam from the light source section, and a reflector which is long in the scanning direction and guides the light beam scanned by the deflector onto a medium to be scanned. , Three points A, B, and C are set on the reflecting surface of the reflector or on a surface facing the reflecting surface, and the side BC forms a triangle whose side is perpendicular to the scanning direction. An adjusting method for an optical scanning device, characterized in that the reflector is independently rotated about two straight lines of BC to adjust the inclination of the scanning line and the positional deviation. 2. The reflectors are moved in parallel by advancing / retreating the three points A, B, C in the same amount in the same direction, and the correction of the length of the scanning line on the medium to be scanned is adjusted. The method for adjusting an optical scanning device according to claim 1, wherein