JPH0862527A - Scanner motor for driving polygon mirror - Google Patents

Abstract

PURPOSE: To provide a scanner motor for driving a polygon mirror which is made small and compact by skillfully combining a polygon mirror and a driving motor. CONSTITUTION: This scanner motor 2 is constituted by combining a rotor 5 obtained by attaching a field permanent magnet 4 to a rotor yoke 12, a stator 9 provided with an armature coil 7, and a rotor shaft 11. In the scanner motor 2, the outside shape of the rotor yoke 12 is formed to be a regular polygon, and a mirror surface is formed by sticking chip shaped mirrors 13 on the peripheral surface of the rotor yoke 12 as the base substance of the polygon mirror, so that the scanner motor 2 integrated with the polygon mirror is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polygon mirror driving motor incorporated in a laser beam printer, a bar code reader or the like to scan a light beam.

[0002]

2. Description of the Related Art As is well known, a laser beam printer writes computer output information on a photosensitive drum using laser light and prints it out by an electrophotographic method. In addition, a polygon mirror (rotary polygon mirror) is used to scan the light beam on the drum.

4 (a) and 4 (b) show a conventional polygon mirror driving device, in which 1 is a polygon mirror and 2 is a scanner motor for rotating the polygon mirror 1 at a high speed (the scanner shown in the figure). The motor is an in-hub type axial gap type brushless DC motor). Here, the scanner motor 2 has a rotor 5 in which a field permanent magnet (a disk-shaped permanent magnet having N and S poles alternately magnetized on the circumference) 4 is mounted on the lower surface of a hub 3 which also serves as a rotor yoke, A stator 9 in which an armature coil 7 and a stator yoke 8 are incorporated in a dish-shaped housing 6, and a bearing 1.
A polygon mirror 1 is connected to a hub 3 of a scanner motor 2. Since the operating principle of such a motor is well known, its explanation is omitted here.

[0004]

However, the above-mentioned conventional structure has the following problems. That is, since the polygon mirror 1 and the scanner motor 2 are independent parts, and there is a limit to the miniaturization of the scanner motor itself, the entire structure in which the polygon mirror is mounted on the scanner motor becomes large, and the laser becomes large. When it is installed in a device such as a printer or a bar code reader, it occupies a large space, which is a major factor that prevents the device from becoming small and compact.

The present invention has been made in view of the above points, and an object thereof is to solve the above-mentioned problems and drive a polygon mirror by skillfully combining a polygon mirror and a drive motor so as to achieve a small size and a compact size. The purpose is to provide a scanner motor for use.

[0006]

To achieve the above object, according to the present invention, a rotor in which a field permanent magnet is mounted on a rotor yoke, a stator provided with an armature coil, a rotor shaft, and The outer shape of the rotor yoke is a regular polygon, and the rotor yoke is used as a base of a polygon mirror to form a mirror surface on its peripheral surface.

Further, the scanner motor described above can be embodied in the following specific configuration. (1) A chip-shaped mirror is attached to the peripheral surface of the rotor yoke. (2) A coating mirror is formed on the peripheral surface of the rotor yoke. (3) As the scanner motor, an axial gap type motor in which the field permanent magnet mounted on the back surface of the rotor yoke and the armature coil of the stator are opposed to each other with an axial gap therebetween is adopted.

(4) As the scanner motor, a radial gap type motor in which the field permanent magnet mounted on the inner peripheral surface of the rotor yoke and the armature coil of the stator are opposed to each other with a radial gap therebetween is adopted.

[0009]

According to the above construction, the rotor yoke of the rotor itself also serves as the base of the polygon mirror, and the scanner motor and the polygon mirror are integrated with each other by forming the mirror surface on the peripheral surface of the polygon mirror. Since it is thin, it can be made small and compact.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. In the drawings of each embodiment, the same members corresponding to those in FIG. 4 are designated by the same reference numerals. Embodiment 1 FIGS. 1 (a) and 1 (b) show an embodiment of an axial gap type motor, and the outer shape of a rotor 5 of a scanner motor 2 is a regular polygon (regular hexagon in the illustrated example). A flat plate-shaped rotor yoke 12 and a field permanent magnet 4 mounted on the lower surface side thereof, and a stator 9 is a flat armature coil 7 facing the field permanent magnet 4 with an axial gap therebetween. The rotor shaft 1 is composed of a stator yoke 8, a bearing 10, and a housing 6 incorporating these parts.
1 is rotatably supported by the bearing 10 and assembled. The rotor yoke 12 also serves as the base of the polygon mirror, and a chip-shaped mirror 13 such as a mirror made of aluminum foil or glass whose surface is mirror-finished on each side is attached to the peripheral surface of the polygon. And form a polygon mirror. With such a configuration, the rotor yoke 12 of the rotor 5 rotates around the rotor shaft 11 by causing a direct current to flow through the armature coil 7 via a sensorless three-phase bipolar drive circuit (not shown).

Then, while rotating the scanner motor 2, by projecting a light beam from the side toward the mirror surface formed on the peripheral surface of the rotor yoke 12 having a polygonal shape, the rotor yoke 12 functions as it is as a polygon mirror. ,Operate. Example 2 FIG. 2 shows an application example of Example 1 described above, in which a glossy metal film is formed on the peripheral surface of a polygonal rotor yoke 12 by a film forming method such as vapor deposition or sputtering. The coating mirror 14 is formed by film formation, and the other structure is the same as that of the first embodiment.

Embodiment 3 FIGS. 3A and 3B show an embodiment of the present invention in which a radial gap type motor is adopted as the scanner motor 2. In this embodiment, the rotor yoke 12 having a polygonal outer shape has a dish shape in which a circular recess is formed in the center on the lower surface side, and the field permanent magnet 4 is mounted on the inner peripheral surface of the rotor yoke 12. Make up 5. Then, similarly to the above-described respective embodiments, the rotor yoke 12
A chip-shaped mirror 13 is adhered to the peripheral surface of, or a coating mirror (see FIG. 2) is formed by a film forming method to form a polygon mirror. On the other hand, the stator 9 has a salient pole-shaped stator core 15 and a stator core 1 that face the field permanent magnets 4 of the rotor 5 with a radial gap therebetween.
5, the armature coil 7 wound around the
It is assembled on the housing 6 together with the bearing 10 of No. 1 to form a scanner motor integrated with a polygon mirror.

[0013]

As described above, according to the configuration of the present invention, the rotor yoke of the scanner motor itself also serves as the base of the polygon mirror, and by combining with the mirror surface formed on the peripheral surface of the polygon mirror, the polygon mirror is formed. It is possible to construct a scanner motor having an integral structure with. As a result, it is possible to achieve a significant reduction in size and size compared to the conventional configuration in which the polygon mirror that is an independent component is mounted on the scanner motor that is a separate component.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a scanner motor corresponding to a first embodiment of the present invention, in which (a) is a vertical side view and (b) is a perspective outline view.

FIG. 2 is an external perspective view of a scanner motor according to a second embodiment of the present invention.

3A and 3B are configuration diagrams of a scanner motor corresponding to Embodiment 3 of the invention, in which FIG. 3A is a vertical sectional side view and FIG. 3B is a partially cutaway plan view.

4A and 4B are configuration diagrams of a conventional polygon mirror driving device, in which FIG. 4A is a vertical side view and FIG. 4B is an exploded perspective view.

[Explanation of symbols]

 2 Scanner Motor 4 Field Permanent Magnet 5 Rotor 6 Housing 7 Armature Coil 9 Stator 11 Rotor Axis 12 Rotor Yoke 13 Chip Mirror 14 Coating Mirror Surface

Claims (5)

[Claims] 1. A rotor yoke having a field permanent magnet mounted thereon, a stator having an armature coil, and a rotor shaft, wherein the rotor yoke has a regular polygonal outer shape. A scanner motor for driving a polygon mirror, characterized in that a rotor yoke is used as a base of the polygon mirror and a mirror surface is formed on a peripheral surface thereof. 2. The scanner motor according to claim 1, wherein
A scanner motor for driving a polygon mirror, wherein chip-shaped mirrors are attached to each side of the rotor yoke. 3. The scanner motor according to claim 1, wherein
A scanner motor for driving a polygon mirror, characterized in that a coating mirror is formed on the peripheral surface of the rotor yoke. 4. The scanner motor according to claim 1, wherein
A scanner for driving a polygon mirror, wherein the scanner motor is an axial gap type motor in which a field permanent magnet mounted on the back surface of a rotor yoke and an armature coil of a stator are opposed to each other with an axial gap. motor. 5. The scanner motor according to claim 1, wherein
A polygon mirror drive characterized in that the scanner motor is a radial gap type motor in which a field permanent magnet mounted on an inner peripheral surface of a rotor yoke and an armature coil of a stator are opposed to each other with a radial gap. Scanner motor.