JPS63155121A - Optical deflecting device - Google Patents

Abstract

PURPOSE:To obtain an optical deflecting device which is easily machined and suits to mass-production as compared with a device which uses a rotary polygon mirror by providing a rotary body equipped with a cylindrical member and a driving device, and forming the external surface of the cylindrical member into a mirror surface and making the center axis noncoincident with the center of the rotary body. CONSTITUTION:The rotary body 5 equipped with the cylindrical member 1 and the driving device 6 which rotates the rotary body 5 are provided and the cylindrical member 1 is so constituted that its external surface is the mirror surface 2 and the center axis is not aligned with the center of rotation of the rotary body 5. Therefore, the center axis of the cylindrical member 11 provided to the rotary body 5 does not meet the center of rotation of the rotary body 5, so the angle of the mirror surface 2 to incident light varies with the angle of rotation of the body 5 and reflected light is deflected and scanned accordingly. Thus, the cylindrical mirror which requires no dedicated working machine for its machining, so the productivity is high and the cost is reduced.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a light deflection device.

BACKGROUND OF THE INVENTION In recent years, methods of recording information by scanning a light beam on a highly luminescent material, as typified by laser beam printers, have been widely used. Conventionally, a device for scanning a light beam is called a light deflection device, and the most common device uses a rotating polygon mirror.

A rotating polygon mirror is a plurality of plane mirrors arranged symmetrically about a rotation axis, and it is well known that the flatness of each mirror surface and their symmetry have a significant effect on deflection accuracy. Therefore, in a rotating polygon mirror, each mirror surface must not only maintain a high level of flatness, but also the angular accuracy between adjacent surfaces must be maintained with high precision.Therefore, various materials and processing methods must be used. However, in recent years, cutting of aluminum alloy using a diamond tool has come to be widely used as the most efficient method.

Problems to be Solved by the Invention However, since the diamond cutting process described above is a highly advanced process, it requires a special processing machine, and its productivity is extremely low. The device has the problem of being expensive.

In view of the above problems, the present invention provides a relatively inexpensive optical deflection device that is easier to process and suitable for mass production than an optical deflection device using a rotating polygon mirror.

Means for Solving the Problems In order to solve the above problems, the present invention includes a rotating body including a cylindrical member, and a drive device for rotating the rotating body, the cylindrical member comprising: The outer surface is a mirror surface,
In addition, the central axis does not coincide with the center of rotation of the rotating body.

Effects The present invention scans and deflects a light beam based on the above-described structure by the following effects. That is, since the central axis of the cylindrical member provided on the rotating body does not coincide with the rotation center of the rotating body, the angle of the mirror surface with respect to the incident light is
Changes occur depending on the rotation angle of the rotating body. with this,
The reflected light is polarized and scanned.

EXAMPLE An example of the present invention will be described below with reference to the drawings.

FIG. 1 schematically shows a case where an optical deflection device according to a first embodiment of the present invention is used in a laser beam printer. 1 is a cylindrical member, and a mirror surface 2 is formed on the outer surface.

The cylindrical member 1 is attached to a rotating shaft 4 by means of a mounting sleeve 3.
The central axis of the cylindrical member l, the mounting sleeve 3, and the rotating shaft 4 which are pivotally attached to the rotating body 5 are collectively referred to as the rotating body 5, is the center of rotation of the rotating body 5, that is, the central axis of the rotating shaft 4. Although it is parallel to the other, it is eccentric. Reference numeral 6 denotes a motor section for rotating the rotating body 5 at a constant rate. 7 is a laser unit. A photosensitive drum 8 is arranged on a plane perpendicular to the rotating shaft 4.

In the optical deflection device configured as described above, the first
The operation will be explained using the diagram and FIG. In FIG. 1, a laser beam emitted from a laser unit 7 is reflected by a mirror surface 2 and forms an image on a photosensitive drum 8. As shown in FIG.

When the motor unit 6 is rotated steadily in this state, the laser beam scans the photosensitive drum 8 as shown below. FIG. 2 shows the scanning process. In FIG. 2, M indicates the position of the mirror surface 2 in FIG. 1, and L indicates the path of reflected light.

As mentioned above, the central axis of the mirror surface 2 does not coincide with the rotation center, so when the rotating body 5 is rotated, the mirror surface 2 causes eccentric movement, and as a result, the mirror surface 2 moves to the position of Mo. Considering the case, the angle between the incident light and the mirror surface 2 is larger than the position M, and the reflected light passes through a path like L'. In other words, as is clear from the fact that the deflection angle of the laser beam changes with the rotation of the mirror surface 2, that is, 0 or more, when the mirror surface 2 is given a smooth rotation, the laser beam is deflected onto the photoreceptor drum 8. In this embodiment, one reciprocating scan is performed per rotation.

3 and 4 regarding the second embodiment of the present invention.
This will be explained with reference to the figures.

FIG. 3 schematically shows a case where the optical deflection device according to the second embodiment of the present invention is used in a laser beam printer. In the same figure, the constituent elements are the same as those in FIG. 1, but differ only in the following two points. 1st
The second point is that the central axis of the cylindrical member 1 and the central axis of the rotating shaft 4 intersect at a certain angle, and the second point is that the central axis of the photosensitive drum 8 and the central axis of the rotating shaft 4 are on the same plane. It is to exist above. FIG. 4 shows the scanning process. In FIG. 4, M indicates the position of the mirror surface 2 in FIG. The light moves to the position L''. That is, as in the case of the first embodiment of the present invention described above, the deflection angle of the laser beam changes with the rotation angle of the mirror surface 2, and the photoreceptor drum 8 However, in the case of the first embodiment of the present invention, the scanning direction was perpendicular to the central axis of the rotating shaft 4, whereas in the case of this embodiment differ in that they lie on the same plane.

As in the above two embodiments, as long as the central axis of the cylindrical member 1 and the central axis of the rotary shaft 4 do not coincide, deflection scanning can be performed even if the two wheels are parallel or intersect. The mirror surfaces are all made by cutting aluminum alloy using a lathe and a diamond tool. Moreover, although the mirror surface is cylindrical, it may be a part of the cylinder.

Effects of the Invention As described above, the present invention includes a rotating body including a cylindrical member,
The cylindrical member has a drive device for rotating the rotating body, and the cylindrical member has a mirror surface on its outer surface and a center line that does not coincide with the center of rotation of the rotating body. By doing so, light can be deflected without using a rotating polygon mirror.

Whereas regular polygonal mirrors such as conventional rotating polygon mirrors require a dedicated processing machine, the cylindrical mirror according to the present invention can be processed using a conventional lathe. It has the effects of high productivity and low cost. In addition, the cylindrical shape has smaller air resistance and less torque loss at the same rotation speed, so it can be driven by a motor with lower torque and also has the effect of lower power consumption.

[Brief explanation of the drawing]

FIG. 1 is a perspective view schematically showing a case where the optical deflection device according to the first embodiment of the present invention is used in a laser beam printer, and FIG. 2 is a perspective view schematically showing the optical deflection device according to the first embodiment of the present invention FIG. 3 is an explanatory diagram showing how the deflection device scans; FIG.
The figure is an explanatory diagram showing the scanning state of the optical deflection device in a second embodiment of the present invention. 1... Cylindrical member, 2... Mirror surface,
3...Mounting sleeve, 4...Rotating shaft,
5...Rotating body, 6...Motor section, 7.
...Laser unit, 8...Photoreceptor drum.

Claims (1)

[Claims] It has a rotating body including a cylindrical member and a drive device for rotating the rotating body, and the cylindrical member has a mirror surface on its outer surface and a central axis aligned with the center of rotation of the rotating body. An optical deflection device characterized in that it does not