JPS58224305A - Manufacture of specular surface of rotary mirror - Google Patents

Abstract

PURPOSE:To obtain the specular surface of a rotary mirror with high reflection effciency and without stripping by coating the surface of a porous alumna ceramic with a thick metallic film then forming a desired thin metallic film at a uniform thickness. CONSTITUTION:An alumina ceramic revolving shaft 7 and polyhedral body part 8 of a rotary mirror 6 are monolithic, and a cylindrical hysteresis ring 10 is seured to the outside circumference in the lower part of a shaft 7. The plate-like part 8 is made in one body with the shaft 7 so as to intersect orthogonally with the axial center of said shaft, and the outside circumferential surface thereof has an exact polyhedral shape of a desired number of faces. The faces of mirror parts 5 are in parallel exactly with the axial center. A thick film 11 of, for example, an Mo-Mn alloy is formed on the faces of the mirror parts 9 and the top and bottom surfaces of the part 8; thereafter, the faces of the mirror parts 9 are lapped and flattened so as not to have inclination to the axial center. A thin Al film of a uniform thickness is formed thereon. The mirror surface which has high reflectivity and high adhesive strength and is free from stripping in spite of high speed rotation is thus obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a method for producing a mirror surface of a rotating mirror used in a laser printer.

(b) Background of the technology Laser printers are fast, silent, and can print kanji, kana, and kanji text and graphics with high quality, so they are used not only as output devices for computers but also for copying machines, facsimile machines, etc. .

Then, the charged photosensitive drum is irradiated with a laser beam that is turned on and off in response to an electric signal to generate a static N1. u t
The optical writing system that creates w uses a rotating mirror that projects a laser beam onto a polygon mirror that rotates at high speed and scans the surface of the photosensitive drum with the reflected light. It is extremely important that the reflection efficiency of a portion of the multifaceted mirror of this rotating mirror be high and that the reflection coefficient be uniform, in order to obtain high-quality printing as well as the rotational accuracy and processing accuracy of the rotating mirror.

(e) Prior Art and Problems A conventional rotating mirror is shown in the sectional view of FIG. In the same figure,
A rotating mirror 1 is a rotating body 2. Polyhedral part 3. and a hysteresis ring 4. A plate-like material made of high-strength aluminum or steel, with a smooth outer periphery and a polyhedral shape (e.g. 8
A polyhedral part 3t formed into a mirror part 5 (a dodecahedron) is fired onto the upper part of a cylindrical rotary body 2 made of alumina sejiminoku in which a meticulously precise shaft hole is formed. They arrived at the same time.

A cylindrical hysteresis ring 4 made of, for example, Fe--Mn and serving as a rotor is fitted into the lower part of the rotating body 2. A stator of a 4D machine (not shown) is disposed on the outer periphery of the hysteresis ring 4, and the shaft hole of the rotating body 20 has a T! It is inserted into a shaft (not shown) that protrudes perpendicularly to the axis of the motor. Then, a dynamic pressure gas bearing is adopted, and the rotary mirror rotates with low friction by using an air journal bearing that restrains the movement in the radial direction and an air thrust bearing that floats in the axial direction. Rotates at high speed.

After the mirror 165 has been lapped, a thin aluminum film is formed by vaporization or sputtering to increase the fouling rate.

However, the rotating mirror 1 is, for example, 40,0OOr, p
Since it rotates at a high speed of -m, the warm thighs are placed on top of each other, and a large centrifugal force acts on the polyhedral part 3, so there is a risk that the fired part will loosen and the mirror part 5 will fall down against the fine details. be.

In order to eliminate this problem, the inventors of the present patent application previously proposed that the rotating shaft 2 and the multi-bent body part 3 be integrally molded from alumina ceramics.

(d) Purpose of the Invention An object of the present invention is to provide a manufacturing method for forming a mirror surface with good reflectance on a portion of a mirror in which a rotating shaft and a polygonal portion are integrally molded using alumina ceramic.

(e) Structure of the Invention In order to achieve this object, the present invention involves coating a portion of the mirror with a metal film to make the porous surface dense by lapping and flattening the mirror, and then reducing the reflectance. A thin metal film with good quality is formed by sputtering or vapor deposition.

(f) Embodiments of the Invention The present invention will be described in detail below with reference to illustrated embodiments.

Figure 2 shows an example of a rotating mirror obtained by the present invention (A).
is a perspective view, and (b) is a sectional view.

In FIG. 2, reference numeral 6 denotes a rotating mirror in which a rotating shaft 7 made of alumina ceramic and a polyhedral part 8 are integrally molded.
0 is fixed. The plate-like polygonal body part 8 is directly fired and integrated with the center of the rotating shaft 7, and the outer peripheral surface has a desired number of surfaces.
E It is a precise polyhedron, and the faces of the mirror part 5 are correctly parallel to the axis.

Each of the mirror parts 9 and the lower end face of the polygonal part 8 are coated with, for example, M, -Mn alloy by a known metallization method or chemical plating method, so that the thickness of the Mo-Mn alloy is coated. Make the membrane 11 into a shape J. Next, each surface of the mirror part 9 is lapped and flattened so that it does not fall with respect to the axis. Thereafter, a thin film of aluminum, for example, having a uniform thickness is formed by a known sputtering method or vapor deposition method.

In this way, by flattening the porous plane of the alumina ceramic with a thick film of MoMn alloy, it is possible to eliminate unevenness in the aluminum thin film, and since it is wrapped in the previous process, it has a uniform thickness. A mirror surface with high reflectivity can be formed on a portion of the mirror. In addition, the aluminum film is not directly formed on the alumina ceramic surface, but is formed via a thick film of MO-Mn alloy, resulting in a mirror surface that has high adhesion strength and does not peel off even when rotated at high speed.

(f) Detailed Description of the Invention As described in detail, the present invention is to coat a porous alumina ceramic surface with a thick metal film, and form a desired thin metal film with a uniform thickness on the seventh step. This has excellent practical effects, such as being able to provide a mirror surface of a rotating mirror that has high reflection efficiency and does not peel off.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a conventional rotating mirror, and FIG. 2 is a perspective view (A) and a cross-sectional view (B) of an example of a rotating mirror according to the present invention. In the figure, 1 and 6 are rotating mirrors, 2 and 7 are rotating shafts, 3.8 is a polyhedron, 4.10 is a hysteresis ring, 5.9t is a part of a mirror, and 11 is a thick metal film.

Claims (1)

[Claims] It is characterized by coating a part of the mirror of a rotating mirror made of ceramic with a metal film, further lapping the surface of the metal film, and then forming a mirror surface of a thin metal film by sputtering or vapor deposition. How to make a rotating mirror surface.