JPH0882736A - Optical scanner - Google Patents

Abstract

PURPOSE: To easily and simultaneously perform adjustment of slope of a reflection mirror in the direction of a main scan and the adjustment of the slope in the direction of a sub-scan for leading a light beam to a position detection element. CONSTITUTION: The reflection mirror 45 reflecting a laser beam deflection scanned by a polygon mirror in a position excepting an effective area for printing and leading it to the position detection element is inserted and held to a tiltable part 47a of a mirror hold member 47 made of a metal plate member with bending processing by a mirror press member 48 to be held. Then, an adjusting pin of an adjusting jig is fitted to an adjusting pin fitting hole 47k, and the mirror hold member 47 is turned in the direction of the arrow A, and the light receiving angle of the laser beam in the direction of the main scan for the position detection element is adjusted, and simultaneously, the adjusting pin of the adjusting jig is moved in the direction of the arrow B, and the tiltable part is inclined, and the reflection surface of the reflection mirror 45 is inclined in the direction of the arrow C, and then, the light receiving angle of the laser beam in the direction of the sub-scan for the position detection element is adjusted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical scanning device applied to an exposure device of a laser printer, for example.

[0002]

2. Description of the Related Art The electrophotographic printing system has been applied to copying machines, printers, facsimiles, etc., and has become an important printing technique. In this printing method, in order to form an electrostatic latent image, exposure is performed after charging the photoconductor, and there are various methods in this exposure method.

An analog exposure system is adopted in the case of a copying machine, while a digital exposure system is adopted in a printer and a facsimile. The digital exposure method uses a solid-state device such as LED (light emitting diode), LCD (liquid crystal device), EEH (edge emitter head), or rotates a polygon mirror or hologram disk. There is a method of deflecting and scanning a laser beam. Recently, a method of deflecting and scanning a laser beam using a polygon mirror has become mainstream.

In the system using a polygon mirror, a position detecting element is arranged in an area where the laser beam scanned by the polygon mirror does not participate in printing, and when this position detecting element detects the laser beam, the output thereof causes the main scanning direction. It is supposed to synchronize. That is, the print data is output after a lapse of a predetermined time after receiving the output signal of the position detection element to determine the start position in the main scanning direction, and the horizontal deviation of the printing caused by the poor division accuracy of the polygon mirror is detected. I'm making it small.

In the method using a polygon mirror, a so-called fθ lens is used to convert a light beam into a convergent light after being deflected by the polygon mirror and a pre-objective type in which the light beam is converted into a convergent light before being deflected by the polygon mirror. There is a known post-objective type.

As a post-objective type optical scanning device, for example, JP-A-1-177512 is known. As shown in FIG. 10, the light beam from the light source 1 irradiates the reflecting surface of the polygon mirror 5 through the collimator lens 2, the cylinder lens 3 and the plano-convex lens 4 in this order. The polygon mirror 5 is rotated at a constant speed by a scanner motor 6 and deflects and scans an incident light beam.
The deflected and scanned light beam is corrected by the aspherical surface correction lens 7 for converging the light beam, and the photosensitive surface of the photosensitive drum 8 is scanned and exposed. In the polygon mirror 5 used here, each reflecting surface is an elliptical surface having power in the main scanning direction.

On the other hand, with the progress of computers, there is an increasing demand for colorization of printers. In a full-color printer, it is known that the electrophotographic method is superior to other methods in terms of print quality.

Among electrophotographic color printers, there are one developing system, one exposing system, four developing system, four exposing system, etc., and the four developing system, four exposing system is called a tandem system. Since it only needs to pass the paper once, it has an advantage that it can cope with high speed. On the other hand, in the tandem system, since the scanning position accuracy of the exposure system appears as a color shift as it is, a high scanning position accuracy is required for the optical scanning device used. In particular, if the output timing of the output signal of the position detection element in the four optical system varies, the color shift in the horizontal direction is left as it is. Therefore, the position of the position detection element and the path of the light beam guided to this position detection element are highly accurate. Is required.

For this reason, conventionally, after the position detecting element is arranged at a predetermined position, the inclination of the reflecting mirror for guiding the light beam to the position detecting element is adjusted.

For example, as shown in FIG. 11, the reflection mirror 9
Is attached to the outside of the vertical surface of the L-shaped mirror holding member 10, and the inside of this vertical surface is pressed by rotating the cam member 11 to push and bend the vertical surface to adjust the tilt angle of the reflection mirror 9. Thus, the positioning of the light beam in the sub-scanning direction is performed, and the positioning of the light beam in the main scanning direction is performed by rotating the mirror holding member 10 about the shaft 13 provided on the base 12, and when these positionings are completed. The mirror holding member 10 is fixed to the base 12 with the screws 14 and 15.

Further, FIG. 12 shows a reflection mirror 1
6 is attached to the inside of the vertical surface of the L-shaped mirror holding member 17, and the mirror holding member 17 is rotated around the reference pin 18 so that the emission angle of the light beam with respect to the position detection element 20 of the position detection unit 19 is increased. Is adjusted, and the height of the position detecting element 20 is adjusted by the adjusting screw 21 in the vertical direction. In this way, the adjustment work is simplified by performing the adjustment in the two directions orthogonal to each other with different parts.

[0012]

However, as shown in FIG.
Adjustment of the rotation of the cam 11 and the mirror holding member 1
Since the rotation is 0, the two adjustments affect each other. For example, if the mirror holding member 10 is rotated to adjust the main scanning direction after the adjustment of the sub scanning direction is completed by the rotation of the cam 11, the tilt angle of the mirror in the sub scanning direction changes again. Therefore, it is necessary to repeat the two-direction adjustment to finally guide the light beam to the target position accuracy, which causes a problem of poor workability.

Further, in the case of FIG. 12, the adjustments in the two directions do not affect each other, but the adjustments are completely independent, so the adjustment work is troublesome, and the optimum adjustment positions in the two directions at the same time. Was hard to find.

Therefore, the present invention provides an optical scanning device capable of easily and simultaneously adjusting the tilt in the main scanning direction and the tilt in the sub-scanning direction of a reflecting mirror for guiding a light beam to a position detecting element. To do.

[0015]

The invention according to claim 1 is
A light source, a polygon mirror that deflects and scans the light beam from the light source, a motor that holds and rotates the polygon mirror, and a position detection element that detects when the light beam scanned by the polygon mirror reaches a predetermined position. And a reflection mirror that reflects the light beam when the light beam scanned by the polygon mirror reaches a predetermined position and guides the light beam to a position detection element, and a mirror holding mechanism that holds the reflection mirror. , The central portion of the long plate-shaped member is bent so as to project upward to form a collapsible portion, and both ends of the plate-shaped member are horizontally folded so as to support the collapsible portion, and the respective fixing portions are provided. The slide part, the inclinable part has a holding part for holding the reflection mirror formed on one side, and the fixed part can rotate and adjust in parallel with the rotation reference part with respect to the mounting surface of this mechanism. Parts are the slide adjustable relative to the mounting surface of the mechanism, in which adjusting the angle of the reflecting mirror by the slide adjustment of the rotational adjustment and the slide portion of the fixed part.

The invention according to claim 2 is the invention according to claim 1, wherein the bending portion between the collapsible portion and the fixed portion and the bending portion between the collapsible portion and the sliding portion are strong. It has a difference.

[0017]

In the invention according to claim 1, the tilting angle of the reflecting mirror, that is, the inclination in the sub-scanning direction is adjusted by slidingly adjusting the sliding portion, and the main scanning of the reflecting mirror is performed by rotating and adjusting the fixed portion. Adjust the tilt of the direction. Moreover, since the slide portion, the fixed portion, and the collapsible portion are formed by one plate-shaped member, two adjustments can be performed at the same time.

In the invention according to claim 1, the inclination of the reflecting mirror can be made to correspond to the slide amount of the slide portion by the strength difference between the two bent portions, and the adjustment amount once adjusted after the inclination adjustment is stabilized. Can be kept at

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIGS. 1 and 2, a semiconductor laser device 32 is arranged as a light source on one end side of a base of a rectangular housing 31, and a laser beam as a light beam is emitted from the semiconductor laser device 32 to a collimator lens 33. After converting to parallel light by the cylinder lens 34, the aperture 3
5 and a plano-convex lens 36 to convert it into a desired converged laser beam and irradiate the folding mirror 37.

The converged laser light is bent by about 90 ° by the bending mirror 37, is simultaneously deflected upward so as to be skew-incident at a predetermined angle, and is incident on the deflecting surface of the polygon mirror 38, and a line image is formed on this deflecting surface. Is imaged as.

The semiconductor laser device 32, the collimator lens 33, the cylinder lens 34, the aperture 35, the plano-convex lens 36 and the bending mirror 37 are fixed to the base member 39 at a predetermined interval and are integrated as an optical block.

The polygon mirror 38 is integrally attached to a scanner motor 40, and is rotated at a constant speed by the motor 40.

The polygon mirror 38 is rotated to deflect and scan the incident convergent laser beam, and the deflected and scanned laser beam is reflected by the M mirror 41 and the L mirror 42.
An image is formed on the photosensitive surface of the photosensitive drum 44 via the aspherical correction lens 43.

Further, the scanning laser light from the polygon mirror 38 scans the photosensitive drum 44 in the main scanning direction, but when it deviates to one side from the effective range for printing, the aspherical correction lens 43. The scanning laser light is reflected by the reflection mirror 45 arranged in front of the M mirror 41.
Also, the light is guided to the position detecting element 46 arranged on the side of the L mirror 42.

The position detecting element 46 serves as a reference for determining the print start position, and the print data is output at a predetermined timing after the position detecting element 46 detects the laser beam to start the exposure operation for the photosensitive drum 44. It is like this.

This optical scanning device is a post-objective type optical scanning device. Correction of field curvature, fθ error, etc.
The polygon mirror 38 has an elliptic cylindrical deflection surface, and this deflection surface and the aspherical correction lens 43 are combined.

The reflection mirror 45 is fixed to a mirror holding mechanism. As shown in FIGS. 3 and 4, the mirror holding mechanism includes, for example, a mirror holding member 47 made by bending a long plate-shaped sheet metal member. The foldable portion 47a is formed by bending it in a U shape so as to project, and both ends are bent horizontally to form a fixed portion 47b and a slide portion 47c that respectively support the foldable portion 47a.

One piece of the inclinable portion 47a, that is,
A holding portion 47d for holding the reflection mirror 45 is formed on the piece on the side of the fixed portion 47b, and a positioning protrusion 47e for positioning the reflection mirror 45 is provided on the holding portion 47d.

A reflection mirror 45 is applied to the holding portion 47d of the inclinable portion 47a, and the reflection mirror 45 is sandwiched by a mirror pressing member 48 manufactured by bending a sheet metal member, and the inclinable portion 4 is held.
It is adapted to be held by the holding portion 47d of 7a. The side of the mirror pressing member 48 that presses the reflection surface of the reflection mirror 45 is divided into two forks.
a and 48a are provided, and the reflection surface of the reflection mirror 45 surrounded by the holding claws 48a and 48a reflects the laser light.

A step 47f that defines the height is provided on one side of the inclinable portion 47a, and the mirror pressing member 4 is provided.
When the reflection mirror 45 is sandwiched by 8, the height of the mirror pressing member 48 is determined in accordance with the step 47f so that the laser beam is surrounded by the pressing pawls 48a and 48a without being blocked by the pressing pawls 48a and 48a. It is designed to reflect on a reflective surface.

A meat stealing hole 47g is formed in each of the bent portion between the inclinable portion 47a and the fixed portion 47b and the bent portion in the central portion of the inclinable portion 47a, so that the bending strength of the bent portion can be reduced. The bending strength of the bent portion between the portion 47a and the slide portion 47c is smaller than that of the bent portion.

The fixing portion 47b has a rotation reference hole 47h fitted into a rotation reference boss 50 provided in a base 49 for fixing the mirror holding member 47, and a screw for fixing the fixing portion 47b to the base 49. Screw hole 47 for passing 51
i is provided. The screw hole 47i is provided in the mirror holding member 4
The diameter is made sufficiently larger than the diameter of the screw 51 so that the screw 51 can pass through even if 7 is rotated in the direction of arrow A in the figure to some extent.

The slide portion 47c is provided with a screw hole 47j through which the screw 52 for fixing the slide portion 47c to the base 49 is inserted. The diameter of the screw hole 47j is made sufficiently larger than the diameter of the screw 52 so that the screw 52 can pass through even if the sliding portion 47c is slid in the direction of arrow B in the figure to some extent.

Further, an adjusting pin fitting hole 47k for fitting an adjusting pin (not shown) of an adjusting jig is provided at the bent top formed in the central portion of the collapsible part 47a.

In this embodiment, the mirror holding member 4
After the reflection mirror 45 is fixed to the unit 7 by the mirror pressing member 48, the mirror holding member 47 is placed on the base 49.
At this time, the rotation reference hole 47h of the fixed portion 47b is fitted into the rotation reference boss 50.

Then, with the adjusting pin of the adjusting jig fitted in the adjusting pin fitting hole 47k, the mirror holding member 47 is moved in the direction of arrow A.
By rotating in the direction, the light receiving angle of the laser beam with respect to the position detecting element 46 in the main scanning direction is adjusted, and the output timing of the signal from the position detecting element 46 is adjusted.

At the same time, if the adjusting pin of the adjusting jig is moved in the direction of arrow B to change the radius of rotation, the collapsible portion 47a of the mirror holding member 47 falls down as shown in FIG. The light receiving angle of the laser beam in the sub-scanning direction with respect to the position detecting element 46 whose surface is tilted in the direction of arrow C in FIG. 3 is adjusted.

When the stable signal can be output from the position detecting element 46 at a desired timing, the fixing portion 47b is fixed by the screw 51 and the sliding portion 47c is fixed by the screw 52.

In this way, the reflection mirror 4 can be adjusted by one adjustment operation.
5, the tilt adjustment in the main scanning direction and the tilt adjustment in the sub scanning direction, that is, both the light receiving angle in the main scanning direction and the light receiving angle in the sub scanning direction of the laser light with respect to the position detection element 46 can be adjusted simultaneously. You can improve the property.

In addition, the work is performed by fitting the adjusting pin of the adjusting jig into the adjusting pin fitting hole 47k and moving the mirror holding member 47 by the arrow A.
This is easy because it is only necessary to rotate the adjusting pin in the direction of arrow B while rotating in the direction.

In addition, the bent portion 47a and the fixed portion 47b and the bent portion at the center of the bent portion 47a are provided with meat scavenging holes 47g to increase the bending strength of the bent portion. 47a
Since the bending strength of the bent portion between the slide portion 47c and the slide portion 47c is made smaller, the bending angle of the bent portion changes when the slide portion 47c slides in the direction of the arrow B. Since only the bent portion is provided, and the bending angle between the inclinable portion 47a and the slide portion 47c hardly changes, the reflecting mirror 45 tilts according to the sliding amount of the slide portion 47c, and the rigidity of one place is also increased. The adjustment amount can be kept stable with.

Further, since the reflection mirror 45 is sandwiched and fixed to the mirror holding member 47 by the mirror pressing member 48, even if the mirror contact surface of the holding portion 47d of the mirror holding member 47 is slightly deformed, the reflection mirror 45 is formed. Can be stably held.

If the flatness of the mirror contact surface is guaranteed to some extent, the reflection mirror 45 may be directly fixed to the holding portion 47d with an adhesive without using the mirror pressing member.

In this embodiment, the adjusting pin fitting hole 47 is used.
Although k is provided at the bent top formed in the center of the inclinable portion 47a, the invention is not limited to this, and the adjustment pin fitting hole 47k may be provided in the slide portion 47c as shown in FIG. Further, as shown in FIG. 7, a bent claw 47m may be provided on the slide portion 47c, and the claw 47m may be pinched by a jig, or the claw 47m may be further provided with an adjustment pin fitting hole 47n.

Further, in this embodiment, a mirror holding member in which the central portion of the collapsible portion 47a is bent in a U shape is used, but the present invention is not limited to this. As shown in FIG. The same action and effect can be obtained by using the mirror holding member 57 including the inclinable portion 57a bent in a V shape, the fixed portion 57b and the slide portion 57c.

That is, when the slide portion 57 slides, the bent portion 57a and the fixed portion 57b are bent, and the folded portion 57 is bent.
All the bent portions of a and the slide portion 57c and the central bent portion of the inclinable portion 57a change the bending angle, and as a result, the inclinable portion 57a changes the inclination as shown by the dotted line in FIG. When the collapsible portion 57a is V-shaped in this way, it is not necessary to provide a meat stealing hole in the bent portion. However, since it is impossible to adjust the reflecting surface of the reflecting mirror downward with this device, it is necessary to consider the arrangement position of the position detecting element and the like.

[0048]

As described above, according to the present invention, the tilt adjustment in the main scanning direction and the tilt adjustment in the sub-scanning direction of the reflecting mirror for guiding the light beam to the position detecting element can be easily and simultaneously performed. The workability can be improved.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of the present invention.

FIG. 2 is a side view showing a partial cross section of the embodiment.

FIG. 3 is a perspective view of a mirror holding mechanism of the embodiment.

FIG. 4 is an exploded perspective view of the mirror holding mechanism of the embodiment.

FIG. 5 is a schematic view showing the operation of the mirror holding member of the embodiment.

FIG. 6 is a perspective view showing another embodiment of the mirror holding member.

FIG. 7 is a partial perspective view showing another embodiment of the mirror holding member.

FIG. 8 is a perspective view showing another embodiment of the mirror holding member.

FIG. 9 is a schematic view showing the operation of the mirror holding member of the embodiment.

FIG. 10 is a perspective view showing a configuration of a conventional optical scanning device.

FIG. 11 is an exploded perspective view showing a conventional example of a mirror holding mechanism.

FIG. 12 is a perspective view showing a conventional example of a mirror holding mechanism and a position detector.

[Explanation of symbols]

 32 ... Semiconductor laser device (light source) 38 ... Polygon mirror 40 ... Scanner motor 45 ... Reflecting mirror 46 ... Position detecting element 47 ... Mirror holding member 48 ... Mirror holding member

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location G02B 26/10 F

Claims (2)

[Claims] 1. A light source, a polygon mirror for deflecting and scanning a light beam from the light source, a motor for holding and rotating the polygon mirror, and a light beam for scanning by the polygon mirror reaching a predetermined position. Position detecting element, a reflection mirror that reflects the light beam when the light beam scanned by the polygon mirror reaches a predetermined position and guides the light beam to the position detecting element, and a mirror holding mechanism that holds the reflection mirror. The mirror holding mechanism is configured such that a central portion of a long plate-shaped member is bent so as to project upward to form a collapsible portion, and both ends of the plate-shaped member support the collapsible portion. By bending in the horizontal direction into a fixed part and a slide part, respectively, and the inclinable part forms a holding part for holding the reflection mirror on one piece, and the fixed part is attached to the mounting surface of this mechanism. Rotation can be adjusted parallel to the rotation reference part, and the slide part can be slide-adjusted with respect to the mounting surface of the mechanism, and the angle of the reflection mirror can be adjusted by rotation adjustment of the fixed part and slide adjustment of the slide part. An optical scanning device characterized by performing. 2. The strength difference is provided between the bent portion between the inclinable portion and the fixed portion and the bent portion between the inclinable portion and the slide portion. The optical scanning device described.