JPH0533810A - Deflection scanning device - Google Patents

Abstract

PURPOSE:To miniaturize a housing by providing a groove in the peripheral surface of the lower part of the housing of the sleeve of a dynamic pressure fluid bearing and fitting an elastic member in the groove and fixing an optical box after arranging the housing in an optical axis. CONSTITUTION:On the top face of the flange part 32a of a housing 32 with a sleeve 31 which is a fixing member, a motor substrate 33 is adhered and fixed, and the lower face of the flange part 32a is taken as a datum surface to be mounted on an optical box 34. A groove 35 is provided in the peripheral surface of the sleeve 31, and an elastic member 36 such as a leaf spring or the like is fitted in this groove from the outside of the optical box 34 to fix the housing and optical box 34. Since the flange part 32a turns into the datum surface to be mounted on the optical box 34 for this reason, the outer diameter of the housing 32 can be made small, and the sleeve 31 and the housing 32 can be easily integrated into a body as a fixing member.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deflection scanning device using, for example, a rotating polygon mirror as a rotating device supported by a hydrodynamic bearing such as a laser beam printer.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for rotary devices that rotate at high speed or with high precision, and in particular, laser beam printers and the like use hydrodynamic bearings that rotate in a non-contact manner.

FIG. 4 is a sectional view of a deflection scanning device of a laser beam printer using a hydrodynamic bearing, and FIG. 5 is an enlarged sectional view of a bearing portion. The rotary polygon mirror 1 is fixed to the upper surface of the flange portion 3 of the rotary shaft 2, and the lower surface of the flange portion 3 is fixed to a rotor 6 to which a drive magnet 4 and an FG magnet 5 constituting a drive motor are fixed. Further, a stator coil 7 is arranged at a position facing the driving magnet 4, and is fixed on a printer substrate 8 on which an FG pattern is printed. A drive circuit and a control circuit (not shown) formed on the hall element and the printed circuit board 8 control the energization of the stator coil 7 to control the rotation of the drive motor. An iron plate-shaped yoke 9 is fixed to the printed circuit board 8 so that the magnetic field of the drive magnet 4 effectively acts on the stator coil 7. The stator coil 7, the printed circuit board 8 and the yoke 9 are fixed to the yoke 9.
Constitutes the motor substrate 10.

The rotary shaft 2 is rotatably fitted in a sleeve 12 fixed in a housing 11 which is a member for fixing a hydrodynamic bearing. A herringbone-shaped shallow groove 13 for generating dynamic pressure is engraved on the outer peripheral surface of the rotary shaft 2 to form a dynamic pressure radial bearing, and in the vicinity of the opening of the sleeve 12,
Spiral shallow grooves 14 are engraved to allow the lubricating fluid to flow below the sleeve 12. Further sleeve 12
A thrust plate 15 is installed on a fixed plate 16 at the lower end of the. A spiral shallow groove 17 is formed on the surface of the thrust plate 15 to form a dynamic pressure thrust bearing,
Further, holes 18 and grooves 19 are provided and used for circulating the lubricating fluid. In addition, on the sleeve 12 side between the shallow grooves 13 and 14 formed on the outer peripheral surface of the rotary shaft 2, an annular recess 20 is formed.
Also, at least one small-diameter hole 21 is provided to ensure the stability of the hydrodynamic bearing portion using the lubricating fluid.

As shown in FIG. 4, a motor substrate 10 is fixed to a housing 11 having a sleeve 12 serving as a fixing member by adhesion or screwing, and the housing 11 is arranged at a predetermined position in an optical box 22. Screw 2
It is fixed by 3. An imaging lens group 24 is arranged in the optical box 22 and faces the photosensitive drum 25.

The laser beam emitted from a light source (not shown) is deflected and scanned by the rotary polygon mirror 1, passes through the imaging lens group 24, and is imaged on the photosensitive drum 25.

[0007]

However, in the above-mentioned conventional example, the screw 23 is used when the rotating device is fixed to the optical box.
Therefore, the screw 23 needs to be installed outside the rotor 6 so as not to hinder the rotation of the rotor 6. Therefore, the size of the housing 11 becomes wider, which causes an increase in weight and cost. Further, the accuracy of the mounting surface of the optical box 22 and the hydrodynamic bearing portion, for example, the housing 11
It is difficult to guarantee the perpendicularity of the inner diameter of the sleeve 12 to the seat surface of the optical box 22 and the optical box 22. Furthermore, screw 23
Since several pieces are used, the number of parts, the number of steps, and the like increase, which also causes a cost increase.

The object of the present invention is to solve the above-mentioned problems,
It is an object of the present invention to provide an inexpensive and highly accurate deflection scanning device that incorporates a hydrodynamic bearing.

[0009]

In order to achieve the above object, a deflection scanning apparatus according to the present invention rotates a deflector for deflecting a beam from a light source by a drive motor supported by a hydrodynamic bearing, In a deflection scanning device provided with a deflector, a drive motor, and a container for accommodating a means for condensing a light beam on an object to be scanned, the fixing member of the hydrodynamic bearing is fixed to the container by an elastic member. It is characterized by.

[0010]

In the deflection scanning device having the above-described structure, the housing of the hydrodynamic bearing is arranged in the container, and the elastic member is fitted in the groove provided on the outer peripheral surface of the sleeve at the lower part of the housing to fix the housing and the optical box. To do.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the embodiments shown in FIGS. The same reference numerals as those of the conventional example indicate the same members. FIG. 1 shows a first embodiment, in which a motor substrate 33 is fixed to the upper surface of a flange portion 32a of a housing 32 having a sleeve 31 as a fixing member by adhesion or screwing, and the lower surface of the flange portion 32a is an optical member. It serves as a mounting reference surface for the box 34. A groove 35 is circumferentially provided on the outer peripheral surface of the sleeve 31 in the lower part of the housing 32, and an elastic member 36 such as a leaf spring is fitted into the groove 35 from the outside of the optical box 34. The housing 32, which is a fixing member, and the optical box 34 are fixed.

With such a configuration, the lower surface of the flange portion 32a of the housing 32 serves as a reference surface for attachment to the optical box 34, so that the outer diameter of the fixing member can be reduced. Further, it becomes easy to manufacture a fixing member in which the sleeve 31 and the housing 32 are integrated.

Therefore, when the sleeve 31 is processed, the inner peripheral surface that acts as a radial bearing, the joint surface with the thrust plate 15 that acts as a thrust bearing, and the flange portion 32a of the housing 32 that serves as a mounting reference surface with the optical box 34 are formed. Simultaneous processing of the lower surface can be easily performed, so that the accuracy is improved and the cost is reduced. Further, since the drive motor can be fixed only by the elastic member 36, the number of parts such as screws and the number of assembling steps can be reduced, and the cost can be reduced.

FIG. 2 shows a second embodiment, in which a part of the optical box 34 is provided with at least one convex projection 37.
It is configured to abut the lower surface of the motor board 33.

The projecting portion 37 operates so as to support the motor substrate 33 when the housing 32, which is a fixing member of the drive motor, and the optical box 34 are fixed by the elastic member 36. That is, when the drive motor rotates, the motor board 33 is prevented from vibrating, and when the connector is inserted into the motor board 33, the motor board 33 is prevented from being deformed. It will be easier.

FIG. 3 shows a third embodiment of the housing 3
An iron-based metal material or a magnetic material is used for 2, and the yoke 9 which is a component of the motor board 33 is the housing 32.
It is formed integrally with. Since the above-mentioned materials are used for the housing 32, it is desirable that the inner surface of the sleeve 31 be surface-treated with Ni, Cr or the like.

As described above, the stator coil 7 or the printed circuit board 8 has the yoke 9 integrated with the housing 32.
Since it is arranged above, it has a simpler structure.

In this embodiment, the case where the sleeve is the fixed member and the shaft rotates is described, but the same effect can be obtained when the sleeve rotates and the shaft is fixed.

[0019]

As described above, in the deflection scanning device according to the present invention, the housing, which is the fixing member of the hydrodynamic bearing, and the optical box are fixed by the elastic member, so that the size of the housing can be reduced. The accuracy of the mounting surface of the optical box can be assured, and the number of parts can be reduced, resulting in cost reduction.

[Brief description of drawings]

FIG. 1 is a sectional view of a first embodiment.

FIG. 2 is a sectional view of a second embodiment.

FIG. 3 is a sectional view of a third embodiment.

FIG. 4 is a sectional view of a conventional example.

FIG. 5 is an enlarged cross-sectional view of a bearing portion of a conventional example.

[Explanation of symbols]

31 sleeve 32 housing 32a Flange part 33 Motor board 34 Optical box 35 groove 36 Elastic member 37 Projection

Claims (6)

[Claims] 1. A deflector for deflecting a beam from a light source is rotated by a drive motor supported by a hydrodynamic bearing, and the deflector, the drive motor, and a means for condensing a light beam on an object to be scanned are housed. A deflection scanning device comprising a container, wherein the fixing member of the hydrodynamic bearing is fixed to the container by an elastic member. 2. The deflection scanning device according to claim 1, wherein a motor substrate of the drive motor is coupled to a fixing member of the fluid bearing, and abutted against a part of the accommodating container. 3. The deflection scanning device according to claim 1, wherein the fixing member is a fixing sleeve. 4. The deflection scanning device according to claim 1, wherein the fixed member is a member including a fixed shaft. 5. The deflection scanning device according to claim 1, wherein the fixing member and a member forming a motor substrate are integrated. 6. The deflection scanning device according to claim 1, wherein the elastic member is provided on the side opposite to the means for condensing the light beam on the object to be scanned.