JPH04115810A - Cutting device for optical member and method of cutting thereof - Google Patents

Abstract

PURPOSE:To cut an optical member into an elliptic shape by fixing a cutter to a rotary shaft, and by inclining the principal axis of the optical member to be cut to an angle with which the optical member is cut into a desired elliptical shape, with respect to a fixed axis. CONSTITUTION:A principal axis passing through the center of a polygon mirror 15 is set at a desired inclined angle of Xdeg. with respect to the rotary axis of a cutter 20. A drive means 22 is operated to rotate the cutter in the direction of the arrow P so that the polygon mirror 15 is fed in the direction W by a feed and rotational angle indexing device 40, and accordingly a first surface 30 is at first formed by a cutting tool 23. Then, the polygon mirror 15 is indexed to an angle of 72deg. by the feed and rotational angle indexing device 40 so as to form a second surface 30 in a similar manner. Thus, first to fifth surfaces 18 are formed so that a polygon mirror 15 having a substantially pentahedron can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cutting device and a cutting method for optical members such as polygon mirrors.

[Prior Art] Conventionally, a polygon mirror having a reflecting mirror on its side surface is used as an optical deflector for deflecting a laser beam and converting it into a scanning beam in a scanning optical system used in a laser printer or the like.

When the shape of this reflective surface is a flat surface, the reflective surface can be obtained by feeding the cut surface of the polygon mirror in a direction perpendicular to the fixed axis (rotation axis) of the cutter wheel.

In such a scanning optical system, particularly in a post-objective type scanning optical system, a polygon mirror whose side surface, which is a reflective surface, is shaped like an ellipse is used.

[Problems to be Solved by the Present Invention] However, even if the reflecting surface is cut into an elliptical shape, even if the contour is processed by a numerical control device using a tool such as an end mill, it is not suitable for use as a scanning optical system. It is not possible to obtain a mirror-like surface precision sufficient to withstand the problem.

[Object of the Invention] Therefore, it is an object of the present invention to solve the above-mentioned problems and provide an optical member cutting device and cutting method capable of cutting the reflective surface of a polygon mirror into an elliptical shape.

[Summary of the Invention] The present invention relates to an optical member cutting device and a cutting method thereof as set forth in the claims.

[Means to solve the problem] See Figure 2.

The cutting cutter 20 cuts the polygon mirror 15, which is an optical member. The cutting tool 23 of the cutting cutter 20 rotates around a rotating shaft 21 . Drive means 2
Reference numeral 2 denotes a motor, which rotates the cutting cutter 20 around the rotating shaft 21.

The main axis R passing through the center of the polygon mirror 15 is inclined at a predetermined angle x0 with respect to the rotation axis 21 of the cutting cutter 20. This predetermined angle X is approximately 0° to 90°
It is possible to set up to close range.

The polygon mirror 15 is movable in the W direction using a feed and rotation angle indexing device 40 which is a control means in the direction of its main axis R. By operating the feed and rotation angle indexing device 40, at least one surface (original surface 18) of the polygon mirror 15 is cut.

The cutting cutter 20 in FIG. 2 has an annular shape and has a cutting tool 23 facing inward.

In another embodiment shown in FIG.
0 is disk-shaped and has a cutting tool 123 facing outward.

The polygon mirror 15 as an optical member is not limited to a pentahedron as shown in FIG. 2, but may be any other polyhedron.

[Operation] See Figure 2. The polygon mirror 15 moves in the direction of the main axis R and cuts at least one original surface 18 by a feed and rotation angle indexing device 40 that is a control means.

[Example 1] Please refer to FIG.

A laser scanning unit 1 is shown in FIG. This laser scanning unit 1 includes a laser light source 2 , an optical scanning device 3 , a light receiving section 4 , fθ lenses 5 and 6 , and a circuit board 7 . This laser scanning unit 1 can be attached to, for example, a laser printer or a laser copier.

Laser light emitted from the laser light source 2 is reflected and scanned by the creation surface 30, which is the scanning surface of the polygon mirror 15 of the optical scanning device 3, and is scanned in a straight line to the light receiving unit 4 via the fθ lenses 5 and 6. It looks like this.

See Figure 2. FIG. 2 shows the polygon mirror 15 mentioned above.
A cutter 20 and the like for forming this are shown.

The cutter 20 is annular or hollow, and the holder 20
a and a cutting tool 23. Cutter 20 is coaxial with shaft 21 . The rotating shaft 21 is rotatable about the central axis CL by operating the driving means 22.

On the other hand, in the polygon mirror 15, the main axis R passing through its central axis can intersect the central axis CL at an angle of X by a control device (not shown). However, the polygon mirror 15 can also be arranged so as to be parallel to the main axis R or the central axis CL using a control device (not shown). The angle of X at this time is, for example, 0 degrees.

The feed and rotation angle indexing device 40 is capable of indexing the rotation angle of the main axis R of the polygon mirror 15. Furthermore, the feed and rotation angle indexing device 40 is capable of reciprocating the polygon mirror 15 in the direction of arrow W, that is, in a direction parallel to the main axis R. The feed and rotation angle indexing device 40 includes, for example, a stepping motor or an actuator. The main shaft R is rotated in the direction of the arrow ■ by the stepping motor. The polygon mirror 15 is moved in the W direction by the actuator.

See Figure 3.

The five original surfaces 18 of the polygon mirror 15 form a pentahedron. The creation surface 30 is formed by using the cutting tool 23 of the cutter 20 shown in FIG. This creation surface 30
has half the length of the major axis a and half the length of the minor axis b
forms part of a virtual ellipse. Create surface 30 like this
5 are formed corresponding to each original surface 18.

The original surface 18 may be a cylindrical surface or the like depending on the shape of the created surface 30.

Referring to FIG. 4, by removing the hatched portion 35 using the cutting tool 23, a polygon mirror 15 formed by five created surfaces 30 can be obtained.

The relationship between the half length a of the major axis shown in FIG. 3 and the half length b of the short axis shown in FIG. 2 is as follows.

cosX=b/a X=cos'(b/a). Note that it is preferable to set the rotation radius of the cutter 20 to a as shown in FIG. 2.

[Operation] First, the raw materials for the polygon mirror 15 are shown in the figure, for example.
Although it is not, it is made of cylindrical aluminum.

That is, in FIG. 2, the main axis R is made parallel to the central axis CL. The outer diameter of the polygon mirror 15 is large enough not to interfere with the cutting tool 23 of the cutter 20.

By operating the driving means 22 to rotate the cutter 20 in the direction of the arrow P, and sending the polygon mirror 15 in the W direction with the feed and rotation angle indexing device 40, the first creation surface 30 is first created.
is formed by the cutting tool 23. Next, the feed and rotation angle indexing device 40 indexes 72 degrees to form the second creation surface 30 in the same manner. In this way, the first to fifth creation surfaces 1
8, a substantially pentahedral polygon mirror can be made as shown in FIG.

In this case, the main axis R and the central axis C are controlled by a control device (not shown).
Set the angle of L to the above-mentioned X.

[Example 2] Please refer to FIG.

In this embodiment, the cutter 120 is disc-shaped.

The outer peripheral surface of this disc-shaped cutting cutter 120 serves as a cutting tool 123.

The cut portion 123 has a substantially semicircular shape.

The rotating shaft 121 of the cutting cutter 120 is connected to the driving means 12
Rotated by 2. The other parts are the same as those of the first embodiment shown in FIG.

The resulting polygon mirror 115 has a concave elliptical surface 130 as shown in FIG.

However, the present invention is not limited to the above embodiments.

For example, a hexahedral structure as shown in FIG. 7 may be used. Note that in FIG. 7, the same parts as in FIG. 4 are given the same numbers.

[Effect of the invention] As described above, by fixing the cutting cutter to the rotating shaft,
The optical member can be cut into an elliptical shape with a simple configuration in which the main axis of the optical member to be cut is inclined with respect to the fixed axis at an angle required for forming the desired elliptical shape.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an example of a laser scanning unit equipped with a polygon mirror as an optical member, and FIG. 2 is a diagram showing Embodiment 1 of the optical member cutting apparatus of the present invention.
3 is a diagram showing the original shape surface and the created surface of the polygon mirror, FIG. 4 is a diagram showing the obtained polygon mirror, and FIG. 5 is a diagram showing Embodiment 2 of the optical member cutting apparatus of the present invention. FIG. 6 is a diagram showing another example of the polygon mirror obtained in the example, and FIG. 7 is a diagram showing still another polygon mirror. 15... Polygon mirror 18...
...Original surface 20...Holder 21... Rotating shaft 22... Drive means 23...・Cutting tool R・・・・・・・・・Main axis CL・・・・・・Central axis D・・・・・・・・・・・・−・Virtual ellipse 30・−・・...Creation surface 35...Deleted portion 40...Feed and rotation angle indexing device a...
・・・・・・・・・Half length b of the major axis of the virtual ellipse
・・・・・・・・・・・・Half the length of the short axis of the virtual ellipse (・2ri FIG, 2 FIG, 3 111111-a + FIG, 4

Claims (1)

[Claims] 1. A cutting cutter (20) having a cutting tool (23) that cuts an optical member (15) and rotates around a rotation axis (21); 21), the main axis (R) of the optical member (15) is set at a predetermined angle with respect to the rotation axis (21) of the cutting cutter (20). (X
) A control means (40) is provided which is arranged to be inclined and allows the optical member (15) to move in the direction of the main axis (R), and at least one surface (
18) A cutting device for an optical member, characterized in that it is configured to cut. 2. A cutting cutter (20) having a cutting tool (23) that cuts the optical member (15) and rotates around the rotation axis (21), and the cutter (20) rotates around the rotation axis (21). The method for cutting an optical member includes a driving means (22) for cutting at least one surface (18) of the optical member (15), the main axis (R) of the optical member (15) being rotated by the cutting cutter (20). A predetermined angle (X
) and move the optical member (15) in the direction of the main axis (R) to remove the optical member (15).
A method for cutting an optical member, the method comprising cutting at least one surface (18) of the optical member. 3. The optical member cutting device according to claim 1, wherein the optical member (15) is a polygon mirror. 4. The method for cutting an optical member according to claim 2, wherein the optical member is a polygon mirror. 5. The optical member cutting device according to claim 1, wherein the cutting cutter is formed into a disk shape with a cutting tool facing outward. 6. The method for cutting an optical member according to claim 2, wherein the cutting cutter is formed into a disk shape with the cutting tool facing outward.