JPH0634904A - Optical scanning device - Google Patents

Abstract

PURPOSE:To sufficiently miniaturize the device and to facilitate the assembly by eliminating an unnecessary space between respective components and providing reference surfaces. CONSTITUTION:The optical scanning device consists of a housing 21 which supports a bearing 22, a scanner motor 23 provided with a rotor 23a formed by supporting a rotary shaft 23b rotatably in the bearing, a right-angled prism 27 fixed on the rotor 23a of the motor 23, a cover member 28 which is so provided on a housing 21 as to cover the scanner motor 23, a semiconductor laser oscillator 29 fitted to the cover member 28, a reflecting mirror 33, and a meniscus lens 34. The lower outer peripheral surface of the cylinder part 21a of the housing 21 is regarded as a plane-directional reference surface X1 for the fitting of the device to the outside and the lowermost surface of the flat plate part of the housing is used as a height-directional reference surface X2 for the fitting of the device to the outside.

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 used in laser printers, laser fax machines, digital copying machines and the like.

[0002]

2. Description of the Related Art For example, in a laser printer, recording information is placed on a laser beam from a semiconductor laser, and the laser beam is deflected and scanned by an optical system to be focused on a charged photoconductor surface which is an image forming surface. The body is exposed to record the record information on the photoreceptor as an electrostatic latent image. The electrostatic latent image is then developed with toner and then transferred to a sheet at the transfer section.

In such an apparatus, basic performance such as print quality and low noise is improved, and the apparatus is downsized and cost is reduced.
The demand for ease of assembly is increasing. Therefore, in the optical scanning device used in such an apparatus, downsizing, cost reduction, and ease of assembly are required.

As a conventional optical scanning device developed to meet such a demand, there is known one disclosed in Japanese Patent Laid-Open No. 63-210807. The one in this publication is shown in FIG. 6 (c).
As shown in, the laser light from the laser diode 1 is applied to the mirror surface of the rotary polygon mirror 4 through the collimating lens 2 and the cylindrical lens 3, and the reflected light is deflected and scanned within a predetermined angle range by rotating the mirror surface. The obtained scanning light is transmitted through the f-θ lens 6, reflected by the reflection mirror 7, and further transmitted through the cylindrical lens 8 to reach the photosensitive drum 9. Further, the synchronization signal for determining the writing start position of the main scanning is such that the laser light from the rotary polygon mirror 4 before the writing which is transmitted through the f-θ lens 6 is reflected by the synchronization detection mirror 9, and the synchronization detection photoelectric element 1
It is made to be incident on 0 and obtained.

When assembling the optical scanning device having such a structure, as shown in FIG. 6 (a), the cylindrical lens 3, the f-θ lens 6 and the cylindrical lens 8 are integrally molded inside the optical housing 11. 6B, and further, as shown in FIG. 6B, an assembly 12 of the laser diode 1 and the collimator lens 2 and a photoelectric element 10 for synchronization detection.
Is fixed to the outer surface of the optical housing 11 with screws,
The rotary polygon mirror 4 and the motor together with the optical housing 11
It is fixed by screwing inside. In addition, the mirrors 7 and 9 are fixed inside the optical housing 11 by a holding plate.

[0006]

In such a conventional apparatus, since the cylindrical lens 3, the f-θ lens 6 and the cylindrical lens 8 are integrally molded and incorporated in the optical housing 11, the optical lens is actually incorporated in the optical housing. Although the number of parts to be attached is small and the assembly is easy, the assembly of the laser diode and the collimator lens, the rotary polygon mirror integrated with the motor, the f-θ lens, etc. are individually arranged in the optical housing. It was impossible to realize a sufficiently small size due to the large space. Moreover, it was insufficient in terms of ease of assembly.

Therefore, the present invention is intended to provide an optical scanning device which can be sufficiently miniaturized and can be easily assembled.

[0008]

SUMMARY OF THE INVENTION The present invention is directed to a housing for supporting a bearing, a motor provided with a rotor for rotatably supporting a rotary shaft on the bearing, and an optical deflection device fixed on the rotor of the motor. The element, the cover member provided on the housing so as to surround the motor, the light beam generator attached to the cover member, and the light beam from the light beam generator are deflected by the light deflection element to be obtained. It comprises a condensing lens part for condensing the scanning beam, and the housing is provided with a reference surface for external attachment and a reference part for attaching the cover member.

[0009]

In the present invention having such a structure, the motor for rotating the light deflection element and the cover member surrounding the motor are attached to the housing, and the light beam generator and the light collecting unit for collecting the scanning beam are attached to the cover member. Since the lens portion for use is attached, the light beam generator, the light deflection element, the motor for rotationally driving the light deflection element, and the condenser lens portion are integrally incorporated. Therefore, a useless space between each component can be eliminated as much as possible. Further, since the housing is provided with the reference surface for external mounting and the reference portion for mounting the cover member, the assembly and the external mounting are extremely easy.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 show the structure of the optical scanning device U. Reference numeral 21 is a housing having a substantially rectangular shape and a cylindrical portion 21a formed in the center. The housing 21 is a stator member of a scanner motor 23. Forming its housing 21
Bearing 22 consisting of a ball bearing in the cylindrical portion 21a of
Is provided. A rotary shaft 23b of a rotor 23a of a scanner motor 23 is rotatably supported on the bearing 22.

In the scanner motor 23, a magnet 23c is integrally attached to a rotor 23a, and the housing 2
A circuit board 25 is fixed to 1 via a spacer 24,
A coil 26 is attached to the back surface of the circuit board 25 facing the magnet 23c.

On the rotor 23a of the scanner motor 23, a right-angle prism 27, which is a light deflection element, is fixed on the rotary shaft 23b.

The rectangular prism 27 has two short sides as reflecting surfaces, and the center of the long side is the rotation axis 2 of the scanner motor 23.
It is fixed according to 3b.

A cover member 28 is provided on the housing 21 so as to surround the scanner motor 23 and the rectangular prism 27.

As shown in FIG. 4, a light emitting unit 32 having a semiconductor laser oscillator 29, a converging lens 30 and a slit 31 integrally housed is screwed to the back surface of the cover member 28 so as to be detachable from the outside. There is.

The cover member 28 has an inclined surface facing the emitting portion of the laser beam from the light emitting unit 32, and a reflection mirror 33 is embedded in the inclined surface so that the laser beam from the light emitting unit 32 is emitted from the inclined surface. Reflection mirror 33
The reflection surface of the right-angled prism 27 is applied from directly above.

A case 35 in which a meniscus lens 34 having a smaller radius of curvature on the exit surface than the entrance surface and having a convex surface toward the image formation surface is integrally molded by resin molding and housed in the front surface of the cover member 28 is shown in FIG. As shown in, it is screwed so that it can be attached and detached from the outside. The meniscus lens 34
Has a function of forming an image on the photosensitive surface of a photosensitive drum, which will be described later, by deflecting light reflected by the reflecting surface of the rectangular prism 27 and deflected and scanned in a plane direction orthogonal to the direction of the rotary shaft 23b of the scanner motor 23. ing.

In the optical scanning device U having such a structure,
The lower outer peripheral surface S1 of the tubular portion 21a of the housing 21 is used as a reference plane X1 in the plane direction when the device U is attached to the outside, and the lowermost surface S2 of the flat plate portion of the housing 21 is used when the device U is attached to the outside. The reference plane X2 in the vertical direction is used. Further, the cover member 2 is provided on the housing 21.
A reference pin 36 for mounting 8 is provided, and a hole formed in the cover member 28 is fitted into the reference pin 36.

Denoted at 38 are screw holes for fixing the optical scanning device U to the outside.

The optical scanning device U is fixed to a device body 41 such as a laser printer as shown in FIG. Then, the deflected light that has passed through the meniscus lens 34 of the optical scanning device U is reflected by the folding mirror 42 and is applied to the photosensitive surface of the photosensitive drum 43.

In the optical scanning device U, the laser light from the semiconductor laser oscillator 29 is converted into a diverging light flux by the converging lens 30, and then it is shaped into a circular beam by the slit 31, and the beam is reflected by the reflecting mirror 33. After reflecting and changing the optical path at a right angle, the two 45 ° reflecting surfaces of the right-angle prism 27 arranged on the rotating shaft 23b of the rotor 23a are irradiated. Incidentally, the reflection mirror 33
The reflected light from is adjusted so that it is incident parallel to the rotary shaft 25b at a distance of several mm from the center of the rotary shaft 23b.

Then, the laser light reflected by the reflecting surface of the right-angled prism 27 is converted into deflected light for deflecting and scanning a predetermined width in the plane direction by the rotation of the right-angled prism 27 by the scanner motor 23, and transmitted through the meniscus lens 34. Then, the folding mirror 42 is irradiated with the light.

In the embodiment having such a structure, the scanner motor 23 is provided on the housing 21, the right-angle prism 27 which is an optical deflecting element is fixed on the rotary shaft 23b of the scanner motor 23, and the housing 21 of the housing 21 is fixed. Since the cover member 28 is attached to the upper part and the light emitting unit 32 having the semiconductor laser oscillator 29 attached thereto, the case 35 having the reflecting mirror 33 and the meniscus lens 34 attached thereto are fixed to the cover member 28, each component is placed between the components. It can be arranged with almost no wasted space, and the overall size and size can be reduced.

Further, since the light emitting unit 32 and the case 35 can be fixed to the cover member 28 from the outside by screwing, the mounting can be facilitated and the direction of the laser beam can be easily adjusted.

Further, when the cover member 28 is attached to the housing 21, the hole of the cover member 28 is fitted into the reference pin 36 provided in the housing 21 for reference alignment, so that the light emitting unit 32 and the reflection mirror are provided. The positions of the right angle prism 27 and the meniscus lens 33 and the meniscus lens 34 can be easily adjusted.

Further, since the optical scanning device U once assembled is unitized, when the optical scanning device U is incorporated into the main body 41 of the device, the mounting thereof becomes easy. Further, as a whole, the number of parts to be incorporated in the apparatus main body 41 is reduced and the assembling becomes easy. Moreover, the optical scanning device U has two reference planes X1.
, X2 are provided, the positioning of the attachment to the apparatus body 41 can be easily performed by the reference surface thereof.

Further, when the optical scanning device U is incorporated in the device main body 41, the lower projection of the cylindrical portion 21a of the housing 21 is embedded in the lower part of the mounting surface of the device main body 41, so that the optical scanning device U is higher than the mounting surface. The height can be reduced, and the height of the apparatus main body can be reduced accordingly, and the size can be reduced.

As a characteristic of the optical scanning device U, the rotation center of the scanner motor 23 is the center of the laser beam scanning width, and the rotation center of the scanner motor 23, which is also a standard of the optical dimension in the optical axis direction, is set as the entire optical scanning device U. Since it is used as a mounting reference, it is possible to perform highly accurate positioning without causing an error factor during assembly.

In the above-mentioned embodiment, a right-angle prism is used as a reflector, and the two short sides of the right-angle prism are reflection surfaces. However, the present invention is not limited to this. One of the sides may be arranged on the rotation axis of the scanner motor, and one long side may be a reflecting surface. In this case, the center of the reflecting surface is aligned with the center of the rotation axis, and the beam is emitted along the center of the rotation axis. Further, the reflector is not necessarily limited to the rectangular prism, and may be an isosceles prism or a deflecting mirror.

[0031]

As described above, according to the present invention, it is possible to achieve a sufficiently small size and easy assembly.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of the present invention with a cover member omitted.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a front view seen from the direction of arrow B in FIG.

4 is a rear view seen from the direction of arrow C in FIG.

FIG. 5 is a schematic perspective view of the optical scanning device according to the embodiment incorporated into a device main body.

FIG. 6 is a perspective view showing a conventional example.

[Explanation of symbols]

21 ... Housing, 22 ... Bearing, 23 ... Scanner motor, 27 ... Right angle prism (light deflection element), 28 ... Cover member, 29 ... Semiconductor laser oscillator, 34 ... Meniscus lens.

Claims (1)

[Claims] 1. A housing for supporting a bearing, a motor provided with a rotor for rotatably supporting a rotation shaft on the bearing, an optical deflection element fixed on the rotor of the motor, and the motor surrounding the motor. As described above, a cover member provided on the housing, a light beam generator attached to the cover member, and a scanning beam obtained by deflecting the light beam from the light beam generator by the light deflector are collected. An optical scanning device comprising: a condensing lens unit that emits light; and a reference surface for mounting the cover member and a reference surface for mounting the cover member on the housing.