JP2716504B2 - Optical scanning device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical scanning device of an image forming apparatus that repeatedly deflects a light beam carrying an image information signal using a rotating polygon mirror to write light on a photosensitive member.

2. Description of the Related Art In a laser printer or a copying machine that reads a document as an image information signal and performs optical writing with a laser beam based on the signal, the laser beam emitted from the laser light source and modulated by the image information signal is repeatedly deflected at a certain angle. In this way, the photoconductor is main-scanned, the surface of the photoconductor is moved at a constant speed in a direction perpendicular to the main scanning direction, sub-scanning is performed, optical writing is performed on the photoconductor, and an image is formed by an electrostatographic process. A rotating polygon mirror is widely used as a deflector for deflecting the laser light.

FIG. 6 is a diagram showing an example of an optical system of an optical scanning device of a laser printer.

A laser beam emitted from the semiconductor laser 1 and modulated by an image information signal is converted into a parallel light beam by a collimating lens 2 and shaped by a beam shaping aperture 3.
The light enters the rotating polygon mirror 5 rotating at high speed through the first cylindrical lens 4, is deflected a predetermined angle once by each mirror surface, and the imaging point is linearly formed on the photosensitive drum 11 by the f-θ lens 6. Is corrected to move at a constant speed, and is reflected by the mirror 7 toward the photosensitive drum 11,
The tilt of the rotary polygon mirror 5 is corrected by the second cylindrical lens 8, an image is formed on the photosensitive drum 11, and optical writing is performed.

The vicinity of both ends of the deflection range by each mirror surface of the rotary polygon mirror 5 is not used for optical writing, and a part of the light beam (indicated by a broken line in the figure) is used as synchronization detection light and reflected by the mirror 9. The light enters the input end 12 of the optical fiber 10, is guided to the synchronization detecting element 13 via the optical fiber 10, and synchronizes the main scanning with the detection signal.

The above-mentioned writing optical system is housed in an optical housing to prevent the influence of dust and to prevent unnecessary light from entering, and each optical element is mounted on the inner surface of the housing. Dustproof glass is provided. In the case of the example shown in the drawing, the second cylindrical lens 8 is also used as the dustproof glass.

Now, the synchronization detection light is accurately transmitted to the input end 12 of the optical fiber 10.
It is necessary to be incident on. However, if the optical axis in the height direction shifts due to replacement of the drive motor of the rotary polygon mirror or the semiconductor laser as the light source, the synchronization detection light reflected by the mirror 9 will not accurately enter the incident end of the optical fiber 10. Therefore, it has been conventionally performed to adjust the inclination of the mirror 9 in the vertical direction so that the reflected light is accurately incident on the incident end of the optical fiber. Even if the horizontal inclination of the mirror 9 is shifted, there is no need to adjust because the timing of incidence of the synchronization detection light on the optical fiber is slightly shifted by the same amount on each surface of the rotary polygon mirror.

It is desirable that the inclination angle of the mirror 9 can be adjusted from the outside without removing the cover of the optical housing.
For example, Japanese Unexamined Patent Publication No. 60-95419 discloses that a mirror 9 for reflecting a synchronization detection light is provided on a bottom plate of an optical housing as shown in FIG.
15 is fixed to a spring plate 16 fixed to the inner surface of the mirror 15, and the vicinity of the upper end of the back surface of the reflecting surface of the mirror 9 is pressed by an adjusting screw 19 screwed into a screw hole 18 provided in a housing side wall 17 facing the back surface of the mirror. A device that adjusts a vertical tilt angle of a mirror by rotating an adjustment screw 19 with a driver 20 is disclosed.

However, in this method, it is necessary to arrange the mounting position of the reflection mirror of the synchronization detection light immediately near the optical housing,
There is a disadvantage that the arrangement of the optical system is restricted. If the reflector is located far from the side wall of the housing, the same adjustment method is to be adopted.A rib is protruded from the bottom of the housing near the back of the reflector, and an adjustment screw is attached to this rib. However, there are various parts inside the optical housing, and there are many cases where a driver or the like does not enter from a required direction, and the angle of the mirror cannot always be adjusted by this method.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described drawbacks of the conventional tilt angle adjusting mechanism of the synchronous detection light reflecting mirror, and more easily adjusts the tilt angle from the upper part of the housing of the optical scanning device and holds the angle after the adjustment. It is an object of the present invention to provide an optical scanning device provided with an adjustment mechanism capable of reliably performing the scanning.

Means for Solving the Problems According to the present invention, in order to achieve the above object, an inclination angle adjusting means of a reflection surface of a synchronization detecting light reflecting member is fixed to the optical housing and extends in a width direction of the light reflecting member. A horizontal support shaft rotatably supporting a lower portion of the member, means for biasing the light reflecting member to rotate about the support shaft in a direction in which an upper portion of the reflection surface is pushed rearward, An adjusting member whose tip abuts on a point on the upper surface opposite to the reflecting surface and whose position can be adjusted in a horizontal plane in a direction substantially perpendicular to the reflecting surface; and a vertical axis engaged with the adjusting member and fixed to the optical housing. And an eccentric cam rotatable around the adjusting member for adjusting the position of the adjusting member.

Since the inclination angle adjusting means of the reflecting surface of the synchronization detecting light reflecting member of the present invention has the above-described configuration, by rotating the eccentric cam rotatable around the vertical axis about the axis, the adjusting member is The means for moving back and forth horizontally in a direction substantially perpendicular to the surface of the reflecting member and urging the reflecting member in the direction in which the upper back surface thereof comes into contact with the front end of the adjusting member always causes the upper back surface of the mirror surface of the reflecting member to be the adjusting member. The tilt angle is adjusted while maintaining the state of being pressed against the tip of the. After the adjustment is completed, if the adjustment member is fixed with a screw that can be turned from above, the adjustment position can be maintained. Since the contact position between the cam surface of the eccentric cam and the adjusting member is almost perpendicular to the direction of the line of action of the biasing force via the adjusting member, if there is no play in the moving direction of the adjusting member and the rotation axis of the eccentric cam, the adjusting member is not moved. Even if it is not fixed, the eccentric cam does not rotate without permission, so that the adjusted position can be maintained.

Since the optical housing is often made flat in the horizontal direction, the reflection member can be easily reflected from above by simply rotating the eccentric cam with a rotating tool such as a driver from above if the housing cover is removed, regardless of the position of the reflection member. The angle of the reflection surface of the member can be adjusted.

Hereinafter, an embodiment of a device for adjusting the inclination angle of a reflection surface of a reflection member according to the present invention will be described in detail with reference to the drawings.

1, 2 and 3 are a sectional view, a top view and an exploded perspective view of an embodiment of the present invention, respectively.

A block 21 is integrally formed on the optical housing bottom plate 15 behind the position where the synchronization detection light reflecting mirror 9 is installed. The lower portion of the mirror-side surface of the block 21 protrudes toward the mirror, and the lower end of the mirror at the corner thereof swingably supports the lower portion of the back surface of the mirror and forms a support shaft 22. Forming a horizontal stopper 23 for the protruding mirror 9;
The support shaft 22 extends between the stoppers 23 on both sides. However, the support shaft may be divided and provided at several places.

A bracket 24 is mounted on the block 21 so as to be horizontally movable within a predetermined range in a direction perpendicular to the surface of the mirror 9 (in the direction of arrow A in FIG. 1) in contact with the upper back surface of the mirror 9. This moving range is a long hole 24b provided in the moving direction of the bracket 24 in the longitudinal direction thereof and a screw screwed into a screw hole 25 formed in the upper surface of the block 21 through the long hole 24b.
A guide groove 27 is formed on the upper surface of the block 21 for guiding both sides of the portion where the long hole of the bracket 24 is provided in order to regulate the moving direction, which is determined by 26. The rear part of the bracket 24 (the side opposite to the mirror 9) has a forked shape,
Is formed. A shallow circular recess 28 is formed on the upper surface of the block 21, and an eccentric cam 30 is provided on the upper surface of a disk 29 fitted into the recess 28. Disc 29 is a bracket
The fork 24 is held down by the fork 24a and is prevented from being pulled out of the recess 28. The cam surface of the eccentric cam 30 is engaged with the back side 24c of the "U" -shaped concave portion of the bracket 24 which is urged rearward via the mirror 9 by the action of a leaf spring 34 to be described later. The cam 24 is inserted into a deformed hole 30a, such as a hexagonal hole or the like, formed vertically in the center of the disk 29 from above, and a rotating tool 32 having a sectional shape adapted to the hole is inserted from above and rotated to move the bracket 24 back and forth. The position can be adjusted in the direction. The shape of the hole 30a provided in the eccentric cam is a hexagonal hole (+) hole, a (-) hole or the like as shown in FIGS. 5 (a), (b) and (c) according to the rotary tool.

The lower surface of the mirror 9 is rotatably supported by contacting the lower portion of the back surface thereof with the support shaft 22 formed as the ridge, and the center of the upper surface of the back surface is brought into contact with the front end of the bracket 24, and the mirror surface side Is pressed and held by a hemispherical protrusion 34a formed on a leaf spring 34 fixed to the upper surface of the housing bottom plate by screws 33. The upper end of the leaf spring 34 is bent so as to cover the upper end surface of the mirror to prevent the mirror from coming off.
The tip portion 24d of the bracket 24 is formed in an arc shape centered on the center of the above-mentioned elongated hole, and the back surface of the mirror 9 is a bracket.
Press the tip of 24 at one point. As shown in FIG. 4, the position where the leaf spring 34 is pressed by the projection 34a must be inside a triangle formed by the support shaft 22 and the tip of the bracket.

The synchronization detection light is incident on the mirror surface of the mirror 9 outside the range of the leaf spring 34, is reflected, and is directed to the incident end 13 of the optical fiber 10.

Therefore, by rotating the eccentric cam 30, the bracket 24 moves in a direction substantially perpendicular to the mirror 9, and the upper part of the mirror pressed against the tip end 24d rotates about the support shaft 22, and the inclination angle Can be adjusted.

After adjusting the tilt angle, the bracket 24 is fixed to the block 21 with the screws 26, so that the mirror 9 can be maintained in the adjusted tilt angle state.

Since the distal end of the bracket 24 is formed in an arc shape centered on the center of the elongated hole 24b, the bracket 24 and the guide groove
Even if there is some backlash between the mirror 27 and the side surface of the mirror 9, the distance between the center of rotation by the screw 26 and the position in contact with the back surface of the mirror 9 does not change, and the tilt angle of the mirror is adjusted. Can be held.

In addition, since the cam surface of the eccentric cam 30 comes into contact with the deep side of the recessed portion of the bracket 24, the force of the leaf spring acts in a direction perpendicular to the contact surface, so that a self-locking mechanism is formed.
If the eccentric cam does not rotate naturally, and if there is no play between the bracket 24 and the guide groove 27 and the shaft support of the eccentric cam and play, the adjusted position can be maintained without fixing with screws. it can.

Effects As described above, according to the present invention, regardless of the mounting position of the mirror, the rotating tool can be inserted from above the optical housing to adjust the tilt angle of the mirror, and the adjusted state is maintained. Since the mirror can be held, the degree of freedom of the mounting position of the mirror increases, and the adjustment work becomes easy.

[Brief description of the drawings]

1 is a sectional view showing the structure of an embodiment of the present invention, FIG. 2 is a top view thereof, FIG. 3 is an exploded perspective view thereof, FIG. 4 is an explanatory view of a mirror pressing position by a leaf spring, and FIG. (A) (b)
(C) is a plan view showing an example of the shape of a key hole for rotating the eccentric cam, FIG. 6 is a perspective view showing an example of an optical scanning device of a laser printer without a housing, and FIG. It is sectional drawing which shows an example of a mirror inclination angle adjustment apparatus. 9: Synchronous detection light reflection mirror (light reflection member), 15: housing bottom plate, 22: horizontal support shaft, 24: bracket (adjustment member), 30: eccentric cam, 34: leaf spring

Claims (1)

(57) [Claims] 1. A light beam emitted from a light source unit and carrying an image information signal is repeatedly deflected by a rotating polygon mirror at a constant angle to form an image on a photoreceptor to perform main scanning. Optical writing is performed on the photoconductor by performing sub-scanning by moving at a constant speed in the perpendicular direction, and a part of the deflection light outside the image writing range is used as main scanning synchronization detection light, and a light reflecting member is used. In the optical scanning device in which an optical system which is made incident on the synchronization detecting means via the optical scanning device is mounted in an optical housing which is flat in the horizontal direction, in order to adjust the deviation of the optical axis in the height direction of the main scanning synchronization detecting light. A horizontal support shaft fixed to the optical housing, extending in the width direction of the light reflecting member, and rotatably supporting a lower portion of the light reflecting member; The top of its reflective surface is backward Means for rotating and biasing the support shaft around the support shaft in the direction in which the light reflecting member is pushed, and a tip abutting on a point on the upper surface opposite to the reflecting surface of the light reflecting member and positioned in a horizontal plane in a direction substantially perpendicular to the reflecting surface An optical scanning device, comprising: an adjustable adjustment member; and an eccentric cam engaged with the adjustment member and rotatable about a vertical axis fixed to an optical housing and configured to adjust the position of the adjustment member. .