JPH11231242A - Optical scanner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a reflection mirror in size without varying an optical path length and making an adjustment sensitivity too sensitive at the time of adjusting a scanning line position of the reflection mirror. SOLUTION: In an adjacent relation to a bearing part 30 bearing a bottom surface of a reflection mirror 26, a 1st support part 32 and a 2nd support part 34 are projectingly arranged and supporting the reflection mirror 26 on the side of the reflection surface at two points. The 1st support part 32 and the 2nd support part 34 are on an extension of a scanning line L formed on the reflection surface of the reflection mirror 26, and when an adjusting screw 40 is drawn out, the reflection mirror 26 turns centering the scanning line L, and a scanning line position on a scanned body is adjusted. In this case, the reflection point on the reflection mirror 26 is not moved front and rear in position, and the optical path length does not change. Moreover, although an unnecessary area of the reflection mirror 26 is eliminated, it is diagonally eliminated, therefore, an adjustment sensitivity will not become too sensitive.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical scanning apparatus used in an electrophotographic apparatus such as a laser printer or a digital copying machine for recording an image by scanning and exposing a laser beam on a scanning object in accordance with image information. Related to the device.

[0002]

2. Description of the Related Art In general, as shown in FIG. 11, an optical scanning device 68 includes a light source device 70, a rotary polygon mirror 72, an imaging lens system 74, and a reflecting mirror 78 for guiding a scanning line onto an object 76 to be scanned.
It has. In such an optical scanning device 68, in order to adjust the scanning line position on the scanned object 76, the reflecting mirror 7 is used.
8 can be rotated.

For example, in an angle adjusting mechanism of the reflecting mirror 78 as shown in FIGS. 12 to 15 (see Japanese Patent Application Laid-Open No. 6-34903), the back surface (non-reflecting surface) of the reflecting mirror 78 is supported by a support portion 80 and an adjusting screw 82. , And the adjusting screw 84 are supported at three points, and a virtual line connecting these three points forms a right triangle.

The lower surface of the reflecting mirror 78 is rotatably supported by a support portion 86, and a leaf spring 90 attached to a housing 88 contacts the reflecting surface of the reflecting mirror 78, so that the reflecting mirror 78 is moved. Support part 80, adjustment screw 82, and adjustment screw 84
It is urging toward.

In such an angle adjusting mechanism, as shown in FIG. 14, when the adjusting screw 84 is pulled out, the reflecting mirror 78 is rotated about the imaginary line α to adjust the scanning line position on the object 76 to be scanned. You. When the adjusting screw 82 (see FIG. 15) is pulled out, the reflecting mirror 78 is rotated about the virtual line β to adjust the scanning line angle on the scanned object 76.

However, the virtual line α that is displaced from the scanning line L
When the reflecting mirror 78 is rotated about the axis, the designed reflection point T moves back and forth by x, and the optical path length (the distance from the light source to the object to be scanned) changes.

As a means for solving such a problem, it is theoretically possible to employ a configuration in which the support portion 80 is also used as an adjusting screw and the three adjusting screws are adjusted so that the optical path length is not changed. Adjustment becomes very complicated and it is impossible in practice. In addition, increasing the number of adjustment screws increases the cost of the angle adjustment mechanism.

Further, the reflecting mirror 78 has a necessary area for reflecting the scanning line L and an unnecessary area which is not used for reflection, so that it cannot be said that the cost performance is good as a product (the larger the total area of the reflecting mirror, Manufacturing costs increase).

However, it is not a problem that the unnecessary area may be simply cut while leaving only the necessary area. This problem will be described below by taking an optical scanning device of a division scanning system as an example.

As shown in FIG. 16, the split-scan optical scanning device uses two light sources 92A and 92B. One light source 92A scans a scanning surface from a scanning start portion to a scanning center portion, and the other light source 92B. Scanning is performed from the scanning center portion to the scanning end portion, and high-speed and high-quality image writing can be performed.

In such a configuration, the imaging lens system 9
The light beams LA and LB including the information having passed through the fourth
A, 96B are reflected toward the cylindrical reflecting mirrors 98A, 98B to form an electrostatic latent image on the surface of the scanned object 100.

The reflecting mirrors 96A and 96B are arranged as shown in FIG.
As shown in the figure, the scanning lines LAL and LBL of the light beams LA and LB are arranged such that the interval in the sub-scanning direction is h1 on the reflecting surface. Further, in order to prevent the upper portion of the reflecting mirror 96A from covering the scanning line LBL, the interval h4 between the scanning line LAL and the upper end is set to be small.

The reflecting mirrors 96A and 96B are supported at three points, respectively (see FIG. 12), and rotate about the imaginary line α. It is necessary to secure a necessary distance β (length of the arm), and the height of the reflecting mirrors 96A and 96B must be at least h.

This is because, as shown in FIG.
The distance h1 between the AL and LBL in the sub-scanning direction and the scanning line LA
As long as the reflection areas of L and LBL are secured, the reflection mirror 96A
It is possible to reduce the height h6 of the
The distance from No. 4 to the imaginary line α becomes short, and the adjustment sensitivity becomes too sensitive (even if the adjustment screw is slightly pulled out, the reflecting mirror is greatly inclined).

Therefore, in order to make the adjustment sensitivity slow,
As shown in FIG. 17, the height of the reflecting mirrors 96A and 96B is required to be at least h, and it is difficult to make the total height lower than h5, so that the demand for downsizing the optical scanning device cannot be met.

[0016]

SUMMARY OF THE INVENTION In consideration of the above facts, the present invention reduces the size of a reflecting mirror without changing the optical path length when adjusting the scanning line position of the reflecting mirror and without making the adjustment sensitivity sensitive. To reduce the manufacturing cost.

[0017]

According to the first aspect of the present invention, there is provided an angle adjusting means for rotatably supporting a reflecting mirror for guiding a scanning line onto an object to be scanned. The angle adjusting means rotates the reflecting mirror about the position of the scanning line on the reflecting surface of the reflecting mirror as a rotation axis. For this reason, the optical path length does not change before and after the reflection point.

According to the second aspect of the present invention, the angle adjusting means supports the reflecting surface side of the reflecting mirror, and the first supporting portion is an extension of the scanning line, and is separated from the first supporting portion by the scanning line. A second support portion that is on an extension of the above and supports the reflecting surface side of the reflecting mirror; and a second supporting portion that is located above or below the first supporting portion or the second supporting portion, supports the reflecting surface side of the reflecting mirror, and An adjusting member for pressing, and a reflecting mirror disposed on the non-reflective surface side of the reflecting mirror;
It is composed of a biasing means for biasing the support, the second support, and the adjustment member, and a support for rotatably supporting the lower surface of the reflecting mirror.

In this configuration, the reflecting surface of the reflecting mirror whose lower surface is rotatably supported by the support portion is stably supported at three points of the first support portion, the second support portion, and the adjustment member. .
Then, the urging means urges the reflecting mirror from the non-reflective surface side of the reflecting mirror toward the first supporting portion, the second supporting portion, and the adjusting member.

The first support and the second support are on an extension of the scanning line, and are pressed by an adjustment member above or below the first support or the second support. That is, by operating the adjustment member, the reflecting mirror rotates around a line (scanning line on the reflecting surface) connecting the first support and the second support. Therefore, the reflection point of the reflecting mirror does not move back and forth, and the optical path length does not change.

According to the third aspect of the present invention, the reflecting mirror leaves an area where the scanning line reflection area, the first support section, the second support section, and the adjustment member abut, leaving an unnecessary area (for scanning line reflection). Area that does not contribute) has been deleted.

As described above, by leaving only the area necessary for the function of the reflecting mirror and reducing the unnecessary area, the size of the reflecting mirror can be reduced and the manufacturing cost can be reduced. Also, the first support portion,
The portion where the second support portion and the adjustment member abut is left, and the line connecting the first support portion and the second support portion and the distance to the adjustment member are maintained at a predetermined value.

Therefore, the distance between the line connecting the first support portion and the second support portion to the adjustment member is reduced, and the adjustment sensitivity does not become sensitive.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a housing 12 of an optical scanning device 10 according to a first embodiment is mounted on a main body frame 14 in an electrophotographic apparatus, and is fixed by screws 16. The housing 12 is provided with a light source device 18. In the light source device 18, a light beam including information generated from a semiconductor laser is collimated by a collimator lens and emitted.

The light beam emitted from the light source device 18 is rotated by a polygonal mirror (not shown) by a rotary polygon mirror 20.
And is incident on the rotating polygon mirror 20. The incident light beam is deflected and scanned by the rotating polygon mirror 20 and is condensed as a light spot on the scanned object 24 by the imaging lens system 22. Next, the light beam including the information passing through the imaging lens system 22 is reflected by the reflecting mirror 26 and
After passing through the second transmission port 28, an electrostatic latent image is formed on the surface of the scanned object 24.

Here, the mounting structure of the reflecting mirror 26 will be described. As shown in FIG. 2 to FIG.
At 2A, support portions 30 are protruded from near both ends in the width direction, and support the lower surface of the reflecting mirror 26 in a tilted state. Further, adjacent to the support portion 30, the first support portion 3
The second and second support portions 34 are projected and support the reflecting surface side of the reflecting mirror 26 at two points.

The first support part 32 and the second support part 34
Is on an extension of the scanning line L formed on the reflecting surface of the reflecting mirror 26, and the reflecting mirror 26 rotates around an axis connecting the first support 32 and the second support 34 as an axis.

On the other hand, an L-shaped adjustment bracket 36 is fixed to the first support portion 32 with a screw 38.
An adjusting screw 4 is provided on the upper part of the adjusting bracket 36.
0 is screwed in, and the distal end supports the upper portion of the reflecting mirror 26 with an interval H from the support point of the first support 32.

Thus, the reflecting surface side of the reflecting mirror 26 is
The first support portion 32, the second support portion 34, and the adjusting screw 40 are supported at three points, and the length of the arm that generates a moment for rotating the reflecting mirror 26 is H.

Further, a spring 42 is fixed to the non-reflective surface side of the reflecting mirror 26 with a screw 38. The projection 42A provided at the tip of the spring 42 comes into contact with the non-reflective surface of the reflecting mirror 26, and attaches the reflecting mirror 26 toward the first support 32, the second support 34, and the adjusting screw 40. To keep the reflecting mirror 26 in a stable state.

The upper portion of the reflecting mirror 26 is cut obliquely from the adjusting screw 40 toward the second support portion 34 to have a trapezoidal shape, and unnecessary regions (regions that do not contribute to the reflection of scanning lines) are deleted. I have. For this reason, as shown in FIG. 5, by cutting the processing base material 27 obliquely, it is possible to manufacture more reflecting mirrors 26 than in the related art, and it is possible to reduce the manufacturing cost.

Next, a method of adjusting the reflection mirror 26 will be described.
When the adjusting screw 40 is extended, the reflecting mirror 26 is rotated about the scanning line L, and the position of the scanning line on the scanned body 24 is adjusted. At this time, the reflection point of the reflection mirror 26 does not move back and forth, and the optical path length does not change.

Although the unnecessary area of the reflecting mirror 26 is deleted, it is cut obliquely and the arm length H is secured, so that the adjustment sensitivity is not sensitive.

Next, an optical scanning device according to a second embodiment will be described. In the second embodiment, the light scanning device 46 is a split-scan optical scanning device, which includes two light source devices 48A and 48B, two first reflecting mirrors 50A and 50B provided for each light source device, and a rotating polygonal surface for deflecting a light beam. A mirror 52, an imaging lens system 54 for condensing the light beam deflected by the rotating polygon mirror 52, a second reflecting mirror 56A for reflecting the light beam passing through the imaging lens system 54 and guiding the light beam to the scanning object 24; 56B and cylindrical reflecting mirrors 58A, 58
B.

In the optical scanning device 46, the rotary polygon mirror 52
Are incident on the same scanning surface at predetermined angles in the main scanning direction and at different incident angles in the sub-scanning direction. While the rotary polygon mirror 52 rotates, the two light beams are deflected in the main scanning direction within a predetermined angle range with respect to the center line.

Next, the deflected light beams are individually
The light beam LB is reflected by the reflecting mirrors 56A and 56B, further reflected by the cylindrical reflecting mirrors 58A and 58B, from the scanning start portion S to the scanning center portion C, and from the scanning center portion C to the scanning end portion. Until E, one line of the scanned object 24 is scanned in two parts.

Here, the mounting structure of the second reflecting mirrors 56A and 56B will be described. As shown in FIG.
The mounting structure of A and 56B is basically the same as that of the first embodiment, and therefore details are omitted, but scanning with a line (rotation axis) connecting the first support portion 60 and the second support portion 62 of the second reflector 56B is performed. Line LB
L does not match.

For this reason, when the adjusting screw 40 is screwed in and the angle of the second reflecting mirror 56B for reflecting the light beam LB including the information from the scanning center portion C to the scanning end portion E is changed, the scanning is slightly increased. The line angle may be out of order.

However, the first support portion 60 and the second support portion 6
2 supports the reflecting surface side of the second reflecting mirror 56B instead of the non-reflecting surface side of the reflecting mirror as in the conventional adjusting mechanism,
The deviation of the scanning line angle is small. The deviation can be eliminated by providing a scanning line angle adjusting mechanism in the cylindrical reflecting mirror 58B.

As shown in FIG. 8, the second reflecting mirror 56
By reducing the area of A and making it trapezoidal, the second reflecting mirror 5
When 6A and the second reflecting mirror 56B are wrapped, there is no need to escape either of the second reflecting mirrors in the vertical direction. As a result, the height of the second reflecting mirror as a whole can be reduced (the height of one second reflecting mirror is sufficient), and the height H of the optical scanning device 46 shown in FIG. Can be reduced in size.

Next, an optical scanning device according to a third embodiment will be described. As shown in FIG. 9, in the third embodiment, the second reflecting mirror 64
A and the mounting structure of the second reflecting mirror 64B are the same as those of the first embodiment.

Therefore, even if the scanning line angles of the second reflecting mirrors 64A and 64B are adjusted, the optical path length does not change.
As compared with the second embodiment, as shown in FIG. 10, the height h2 of the second reflecting mirror as a whole is higher.

This is because the interval h1 between the scanning line LAL and the scanning line LBL is ensured, and the lower part of the second reflecting mirror 64B is used as the reflection area of the scanning line LBL to cut off the upper unnecessary area. It is higher by the distance h3 between the lower surface of the mirror 64B and the lower surface of the second reflecting mirror 64A.

However, as compared with the second embodiment, the manufacturing cost of the second reflecting mirror is reduced, so that the optical scanning device 46 can be manufactured at low cost.

[0045]

According to the present invention, the optical path length does not change when the scanning line position of the reflecting mirror is adjusted. In addition, the adjustment sensitivity is low, and further, by cutting unnecessary regions of the reflecting mirror, manufacturing costs can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing an optical scanning device according to a first embodiment.

FIG. 2 is a perspective view showing a mounting structure of a reflecting mirror of the optical scanning device according to the first embodiment.

FIG. 3 is a front view showing a support state of a reflecting mirror of the optical scanning device according to the first embodiment.

FIG. 4 is a side view showing a mounting structure of a reflecting mirror of the optical scanning device according to the first embodiment.

FIG. 5 is an explanatory diagram showing a manufacturing process of the reflection mirror of the optical scanning device according to the first embodiment.

FIG. 6 is a schematic perspective view showing an optical scanning device according to a second embodiment.

FIG. 7 is a perspective view showing a mounting structure of a reflecting mirror of the optical scanning device according to the second embodiment.

FIG. 8 is a front view showing a support state of a reflecting mirror of the optical scanning device according to the second embodiment.

FIG. 9 is a perspective view showing a mounting structure of a reflecting mirror of an optical scanning device according to a modification.

FIG. 10 is a front view showing a supporting state of a reflecting mirror of an optical scanning device according to a modification.

FIG. 11 is a schematic perspective view showing a conventional optical scanning device.

FIG. 12 is a front view showing a supporting state of a reflecting mirror of the conventional optical scanning device.

FIG. 13 is a side view showing a mounting structure of a reflecting mirror of a conventional optical scanning device.

FIG. 14 is a side view showing a mounting structure of a reflecting mirror of a conventional optical scanning device.

FIG. 15 is a side view showing a mounting structure of a reflecting mirror of a conventional optical scanning device.

FIG. 16 is a conceptual diagram showing a split-scan optical scanning device.

FIG. 17 is a front view showing a supporting state of a reflecting mirror of the optical scanning device of the division scanning system.

FIG. 18 is a front view showing a modification of the reflecting mirror.

[Explanation of symbols]

 26 Reflecting mirror 30 Bearing 32 First support 34 Second support 40 Adjusting screw (adjusting member) 42 Leaf spring (biasing means) 56A Reflecting mirror 56B Reflecting mirror 64A Reflecting mirror 64B Reflecting mirror

Claims (3)

[Claims] 1. An optical scanning device comprising a light source, a rotating polygon mirror, an imaging lens system, and a reflecting mirror for guiding a scanning line onto an object to be scanned, wherein the position of the scanning line on the reflecting surface of the reflecting mirror is rotated. As an axis,
An optical scanning device comprising an angle adjusting means for rotatably supporting a reflecting mirror. 2. The apparatus according to claim 1, wherein the angle adjusting means supports a reflecting surface of the reflecting mirror, and includes a first support portion on an extension of the scanning line, and a first support portion separated from the first support portion and on the extension of the scanning line. A second support portion for supporting a reflection surface side of the reflection mirror; and a reflection surface side of the reflection mirror which is located above or below the first support portion or the second support portion and supports the reflection surface side of the reflection mirror. An adjusting member for pressing, disposed on the non-reflective surface side of the reflecting mirror, and
An optical scanning unit comprising: a biasing unit configured to bias the support unit, the second support unit, and the adjustment member; and a support unit configured to rotatably support a lower surface of the reflecting mirror. apparatus. 3. The method according to claim 2, wherein the reflecting mirror is a reflection area of the scanning line,
3. The device according to claim 2, wherein the first support portion, the second support portion, and an adjustment member are removed except for a portion in contact with the adjustment member.
3. The optical scanning device according to claim 1.