JPS60217330A - Rotary polyhedral mirror assembly body - Google Patents

Abstract

PURPOSE:To execute a scan with high accuracy by interposing a spacer having an uneven part on the peripheral part, between a flange for clamping a rotary polyhedral mirror through which a revolving shaft has been inserted, from both sides, and the rotary polyhedral mirror, and preventing a temperature rise of the rotary polyhedral mirror. CONSTITUTION:A revolving shaft 3 is inserted through a rotary polyhedral mirror 1, and the rotary polyhedral mirror 1 is clamped from both sides by a flange 4 and a nut 5 through a spacer 8. The spacer 8 has a notch 9 and a projecting part 10 on its peripheral part, and the tip part of the projecting part 10 contacts directly both sides of the rotary polyhedral mirror 1. As the polyhedral mirror rotates, air goes in and out to and from the notch part 9. The heat transmission part through which heat generated by a motor 2 is transferred to the rotary polyhedral mirror 1 becomes small, and also by a fan effect of the spacer 8, a temperature rise of the rotary polyhedral mirror 1 is prevented. In this way, the thermal deformation becomes extremely small, and a scan is executed with high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a mechanical scanning device used in a printer or facsimile machine that scans with a laser to read or record documents, or a laser scanning device for measurement or inspection. This invention relates to a rotating polygon mirror assembly.

Structure of employee examples and their problems A conventional example of such a rotating polygon mirror assembly is shown in FIG.

1 is a rotating polygon mirror, and a rotating shaft 3 is directly connected to a motor 2.
Then, the rotary polygon mirror 1 is rotated by a motor fixed by a nut 5 through a flange 4, and the laser beam is reflected by a reflective surface 6 parallel to the rotation axis to perform mechanical scanning. is a sectional view of a conventional example, in which a rotating polygon mirror 1 is fixed to a shaft 3 by a flange 4.

Further, an armature 7 of a motor is attached to one end of the shaft, the shaft 3 is supported by a bearing (not shown), and a rotational force is applied to the armature 7 by a stator of the motor (not shown). rotation is performed.

When using this configuration, the motor 2
fever occurs. This heat is accompanied by an increase in the temperature of the shaft 3, which further increases the temperature of the rotating polygon mirror 1.

This causes thermal deformation of the rotating polygon mirror 1, deforms the reflecting surface 6, and changes the perpendicularity of the reflecting surface 6 to the rotating shaft 3, making it difficult to perform highly accurate mechanical scanning.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a rotating polygon mirror assembly which eliminates the above-mentioned drawbacks, reduces thermal deformation of the rotating polygon mirror, and allows highly accurate mechanical scanning.

SUMMARY OF THE INVENTION The present invention has been made to achieve the above-mentioned object.The rotating polygon mirror inserted into the rotating shaft is fastened to the rotating shaft from both sides by supporting means, and the rotating polygon mirror is The object of the present invention is to provide a rotating polygon mirror assembly in which the polygon mirror and the supporting means are brought into contact with each other on some of their uneven surfaces.

6 pages Description of examples Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 shows a front view of a rotating polygon mirror assembly which is an embodiment of the present invention.

In this example, the rotating polygon mirror 1 is fixed via the spacer 8 without directly holding the rotating polygon mirror with the flange 4. FIG. 4 is a perspective view of the spacer 8. The spacer 8 has a notch 9 and is in contact with the rotating polygon mirror 1 only through the protrusion 1o. Therefore, the temperature rise due to the heat generated by the motor 2 via the shaft 3 and flange 4 is reduced because the only heat transfer part is the protrusion 10.
Also, due to the inflow and outflow of air through the notch 9,
Since the spacer 8 is cooled, the temperature rise and thermal deformation of the rotating polygon mirror 1 are extremely reduced.

The rotating polygon mirror 1 is made of glass with a thermal expansion coefficient of 7.4 x 10'/°C, and the spacer 8 is made of glass with a thermal expansion coefficient of 9.4 x 1.
An octahedral rotating polygon mirror assembly with an outer circumferential diameter of 174 cm was fabricated using a single laminate of 0 h. -10℃6・t
In the temperature range of −7 to 35°C, the change in the perpendicularity of the reflecting surface of the rotating polygon mirror 1 to the rotation axis 3 is within ±3″, and a highly accurate rotating polygon mirror assembly can be obtained. In this example, the spacer 8 is provided separately from the flange 4, but it is of course possible to provide the flange 4 with a notch 9 similar to the spacer 8 and omit the spacer 8.

FIG. 5 is a sectional view of a rotating polygon mirror assembly according to a second embodiment of the present invention. In this case, as described above, the flange 4 has a notch 9, and the flange is formed by only a 1° protrusion. It is in contact with the rotating polygon mirror 1. Furthermore, the flange is provided with a hole 11 passing through the upper and lower surfaces. The holes 11 may be provided on both the upper and lower flanges 4 that sandwich the rotating polygon mirror, or may be provided only on one side.

If installed only on one flange, rotate polygon mirror 1 and shaft 3.
A gap 12 is provided between them. In such a structure, as the rotating polygon mirror assembly rotates, an air flow is generated on the surface 13 of the rotating polygon mirror 1 perpendicular to the rotation axis 3 from the center of the axis toward the outer periphery of the polygon mirror. As shown by the arrow in Figure 7, air is sucked in through the hole 11, and
3, the air reaches the outer periphery of the rotating polygon mirror 1.

The rotating polygon mirror 1 is naturally cooled by this air flow, further preventing a rise in temperature.

FIG. 6 is a sectional view of a rotating polygon mirror assembly according to a third embodiment of the present invention, in which a filter 14 is provided on the suction side of the hole 11 penetrating the flange 4, that is, on the side not close to the rotating polygon mirror 1. Installation. The air is filtered by the filter 14, and clean air from which dust has been removed is supplied for cooling. Therefore, even if the rotating polygon mirror 1 is rotated for a long time, no dust will adhere to it, and efficient reflection of laser light can be ensured.

FIG. 7 shows another embodiment in which the rotating polygon mirror 1 itself is provided with a protrusion 16, which contacts the plane flange only through this protrusion. The notch 16 provides air cooling.

Furthermore, the spacer 8 in the embodiment shown in FIG. 3 and the flange 4 in the embodiment shown in FIGS.
By using a material whose coefficient of thermal expansion is equal to or very close to that of the rotating polygon mirror 1 (preferably a difference within ±30%), even if there is thermal expansion between the flange 4 and the polygon mirror 1, The rotating polygon mirror 1 is free from deformation and can perform highly accurate scanning over a wide temperature range.

Effects of the Invention In short, the present invention has a structure in which a rotating polygon mirror inserted into a rotating shaft is held between both sides by supporting means, and the rotating polygon mirror and the supporting means are mutually connected to each other on a part of the uneven surface. This provides a rotating polygon mirror assembly that is in contact with the other mirrors, so that even if the temperature of the motor increases, the temperature change in the rotating polygon mirror is kept to a minimum, and thermal deformation is extremely small.
A high-precision rotating polygon mirror assembly is ensured for a wide range of usage conditions, high-precision mechanical scanning is possible, and high-resolution laser reading and recording can be realized.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a conventional rotating polygon mirror assembly, FIG. 2 is a sectional view of the conventional example, and FIG. 3 is a front view of the rotating polygon mirror assembly in the first embodiment of the present invention. - FIG. 4 is a perspective view of the spacer portion in the above embodiment, FIGS. 6 and 6 are sectional views of the rotating polygon mirror assembly in the second and third embodiments of the present invention, and FIG. FIG. 7 is a perspective view of a rotating polygon mirror section in another embodiment of the invention. 1... Rotating polygon mirror, 3... Rotating axis, 4
...Flange, 8°°°...Spacer, 9.
...Notch key, 14...Filter, 16.
·····protrusion. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 3 Figure 2 Figure 3 Figure 6 Figure 7 Figure 6

Claims (1)

[Scope of Claims] (1) A rotating polygon mirror inserted into a rotating shaft, and support means for fastening the rotating polygon mirror to the rotating shaft from both sides, wherein the rotating polygon mirror and the supporting means are , a rotating polygon mirror assembly 0 characterized in that some of the uneven surfaces are in contact with each other. A rotating polygon mirror assembly according to claim 1, further comprising: a rotating polygon mirror assembly; (3) The rotating polygon mirror assembly according to claim 2, wherein, of the spacer and the flange, at least the spacer has a thermal expansion coefficient equal to or very close to that of the rotating polygon mirror. (4) The rotating polygon mirror assembly according to claim 1, wherein the support means is a flange, and a notch is provided on a surface of the flange that contacts the rotating polygon mirror. (6) The rotating polygon mirror assembly according to claim 4, wherein the coefficient of thermal expansion of the flange is equal to or very close to that of the rotating polygon mirror. (6) The rotating polygon mirror assembly according to claim 1, wherein a protrusion is provided on the surface of the rotating polygon mirror that is in contact with the support means. (Force) A gap is provided between the rotating shaft and the rotating polygon mirror, and the airflow generated as the rotating polygon mirror rotates is directed to the outer circumference on the side surface of the rotating polygon mirror through the gap. A rotating polygon mirror assembly 0 according to claim 1, characterized in that at least one of the supporting means is provided with a wooden part that penetrates the upper and lower surfaces of the supporting means. A rotating polygon mirror assembly according to claim 1. (9) A rotating polygon mirror assembly according to claim 8, characterized in that a filter is provided to cover the hole. 3 page