JPH04165937A - Rolling bearing for scanner motor of laser beam printer - Google Patents

Abstract

PURPOSE:To increase the life of a rolling bearing for a scanner motor by making the roller of a bearing out of ceramic material. CONSTITUTION:The bearing is composed of an inner ring 1, an outer ring 2, rollers 3 between the inner and the outer rings, a holder 4, which holds the rollers 3 at regular intervals in circumferential direction, and noncontact seals 5, which are installed at both ends. And the roller 3 is made of ceramic material. For said bearing, the roller 3 is made of ceramic material, so roughening is hard to occur at the surface of the rolling faces of the inner and outer rings 1 and 2 and the surface of the roller. What is more, it will do to make the layer consisting of ceramic material at the surface of the steel roller, in place of making the roller 3 of ceramic material.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to improvements in rolling bearings used in scanner motors of laser beam printers.

[Prior Art] FIG. 2 shows a scanner motor of a laser beam printer. The scanner motor includes a main shaft (22) inserted into a housing (21), a rotor part (23) formed on the main shaft (22), a stator part (24) arranged opposite to the rotor part (23), and a main shaft (22). ) rotatably supports the bearing (
25), and a polygon mirror (26) coupled to the main axis (22).
). When a current is passed through the stator section (24), the rotor section (23) rotates due to the excitation force of the stator coil, and along with this rotation, the polygon mirror (26) connected to the main shaft (22) rotates. Laser light that enters the polygon mirror (26) from the laser light source through a predetermined optical system is reflected by the polygon mirror (26) and scans the surface of the photosensitive drum.

In addition, in figure a, both ends of the main shaft (22) are connected to bearings (25).
The figure shows the main shaft (22
) is supported by a bearing (25).

[Problems to be Solved by the Invention] If the polygon mirror (26) has rotational blur or uneven rotation, the scanning function of the ζ laser beam will be hindered, so the main axis (22)
requires high rotational accuracy. In addition, since the laser printer is used in a general office,
Low noise is required for the entire motor section. For this reason, the life end point of the bearing (25) that supports the main shaft (22) is set according to stricter standards than for general bearings. Furthermore, the main shaft (22) is typically 20,000 to 30,000 r p
Considering the high speed rotation at m, the life of the bearing (25) is considerably shortened.

Therefore, an object of the present invention is to increase the life of the rolling bearing for the scanner motor.

[Means for Solving the Problems] In the present invention, the rolling elements of the bearing are formed of a ceramic material.

[Operation] Surface roughness occurs on the raceway surfaces of the inner and outer rings and on the surfaces of the rolling elements due to wear due to rolling contact, which causes vibration and noise. In general, it is thought that wear of the contact surface occurs because microprotrusions on the surface are fused together under contact surface pressure, and the fused portion is scraped off from the surface by shearing force. This fusion wear is particularly likely to occur when similar metals come into contact. However, in the rolling bearing according to the present invention, since the rolling elements are formed of a ceramic material, fusion wear is less likely to occur between the raceway surface and the surface of the rolling element.

FIGS. 3C and 3D show the surfaces of the rolling elements after the rolling bearing according to the present invention and a normal rolling bearing using steel rolling elements are rotated under prescribed conditions for a prescribed period of time. As is clear from the figure, the surface of the ceramic rolling element has less surface roughness than the surface of the steel rolling element. In addition, a and b in the same figure
shows the inner raceway surfaces of both bearings before the test.

[Example code] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a rolling bearing according to the invention.

This bearing has an inner ring (1), an outer ring (2), and an inner/outer ring (1).
(2) Consists of rolling elements (3) interposed between them, cages (4) that hold the rolling elements (3) at equal intervals around the circumference, and non-contact seals (5) attached to both ends. The rolling elements (3) are made of ceramic material.

In this bearing, the rolling elements (3) are made of ceramic material, so as mentioned above, the raceway surfaces of the inner and outer rings (1) and (2) and the surface of the rolling elements (3) become rough. Hateful.

Incidentally, instead of forming the rolling element (3) from a ceramic material, a layer made of a ceramic material may be formed on the surface of a steel rolling element.

[Effects of the Invention] In the rolling bearing according to the present invention, since the rolling elements are formed of a ceramic material, surface roughness is less likely to occur on the raceway surfaces of the inner and outer rings and on the surfaces of the rolling elements. Therefore, according to the present invention, the life of the bearing is increased, and good vibration and acoustic characteristics are maintained even after long-term use.

Figures 4A and 4B show the results of tests conducted to confirm the above effects. The test was conducted on six test bearings, and No. 1 to 6 in the figure indicate the numbers of the test bearings. As is clear from the test results, the rate of increase in vibration and noise values over time for bearings using ceramic rolling elements is considerably smaller than for bearings using steel rolling elements.

Figures 5A and 5B show the inner raceway surface after 100 hours. As shown in FIG. 5A, there is almost no surface roughness on the inner ring raceway surface of the bearing using ceramic rolling elements. On the other hand, the inner ring raceway surface of a bearing using steel rolling elements has surface roughness, as shown in FIG. 5B.

The above are the results when the test time was 100 hours, but it is thought that the superiority of the rolling bearing according to the present invention becomes even more remarkable as the test time becomes longer.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing a rolling bearing according to the present invention, Fig. 2 a and b are sectional views showing a scanner motor of a laser beam printer, Fig. 3 is a micrograph showing test results, Fig. 4A and 4B The figure is a table showing the test results, and Figures 5A and 5B are micrographs showing the test results. 3...Rolling element 21...Housing 22...
Main axis 25...Bearing 26...Polygon mirror 1, Indication of the incident 1990 Patent Application No. 290131 2, Name of the invention Laser beam printer scanner motor River transmission bearing 3, Person making the correction Relationship with the incident Patent applicant address: 1-3-17 Kyomachibori, Nishi-ku, Osaka, Osaka Prefecture
Name: NT Co., Ltd. 4, Agent: 550 Address: 1-15-2 Edobori, Nishi-ku, Osaka, Osaka Prefecture
No. 6 Osaka Shoko Building 8th floor Telephone: 08-443-9541 6. Specification and drawings subject to amendment [Figure 3 a shows the structure of the inner ring raceway surface (surface) before testing of a bearing using steel balls This is a microscopic photograph. Figure 3 is a micrograph showing the structure of the inner raceway surface (surface) of a bearing using ceramic balls before testing. FIG. 3C is a micrograph showing the structure of the inner raceway surface (surface) of a bearing using steel balls after a test. FIG. 3d is a micrograph showing the structure of the inner ring raceway surface (surface) after testing of a bearing using ceramic balls. ”■
, 6th member [lines 5 to 16 are corrected as follows. 1. FIG. 58 is a micrograph showing the structure of the inner raceway surface (surface) of a bearing using ceramic balls after a test. FIG. 5B is a micrograph showing the structure of the inner ring raceway surface (surface) after testing of a bearing using steel balls. ”■0 Figures 3 and 5 in the drawings are corrected as shown in the attached sheet.

Claims (1)

[Claims] (1) A rolling bearing for a scanner motor of a laser beam printer, characterized in that the rolling elements of the rolling bearing, which rotatably supports a main shaft to which a polygonal mirror is coupled and rotates within a housing, are made of a ceramic material.