JPH0324516A - Optical deflector - Google Patents

Abstract

PURPOSE:To reduce the possibility that a member is peeled owing to heat generation by a motor, etc., by providing an elastic member which presses a polygon mirror fitted to the center part of a rotary member axially against a base part. CONSTITUTION:A flywheel 16 consists of the discoid base part 17 and the center part 18 whose upper projects in a conic shape. The polygon mirror 19 made of resin while having a flat reflecting surface by vapor-depositing a metallic film on the outer peripheral surfaces is fixed on the base part 17 while surround ing the center part 18 of the flywheel 16. Further, a leaf spring 20 fitted to the upper end of a rotary shaft 15 presses the polygon mirror 19 against the flywheel 16 from above. Consequently, the polygon mirror 19 is pressed against a tapered join surface present between rotary members 15 and 16 and even if those members vary with temperature, the join state is held constant.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an optical deflector used in an optical scanning mechanism of a laser printer.

2. Description of the Related Art In recent years, optical scanning mechanisms have been developed for use in devices such as laser printers. There are various types of such optical scanning mechanisms, and one typical device is an optical deflector that rotates a polygon mirror placed on the optical axis of a light source at high speed.

Therefore, a conventional example of this optical deflector will be explained based on FIGS. 7 and 8. First, this optical deflector 1 is provided with a polygon mirror 4 made of a hexagonal metal plate with a fitting hole 2 formed in the center and six flat reflective surfaces 3 formed on the outer periphery. The polygon mirror 4 is fixed on a flywheel 6 mounted approximately at the center of the rotating shaft 5 fitted in the fitting hole 2 by being pressed by a leaf spring 7 or the like. Further, the rotating shaft 5 is rotatably attached to the housing 10 via bearings 8 and 9,
A motor section 1 is formed by a coil 11 continuously arranged in a circle centered on the rotation axis 5 in the housing 10 and a magnet l2 attached to the lower surface of the flywheel 6.
3 is formed.

In such a configuration, in this optical deflector l, when light emitted from a laser light source (not shown) or the like is incident on the reflector 3 of the polygon mirror 4 rotated by the driving force of the motor part l3, the reflected light is becomes scanning light corresponding to the rotation of the polygon mirror 4. Therefore, this optical deflector l will be used in various optical scanning mechanisms.

Problems to be Solved by the Invention The optical deflector l as described above consists of a rotating polygon mirror 4.
Since light scanning can be easily performed by reflecting incident light on the reflective surface 3 of the laser beam, it is used for forming latent images in laser printers. Generally, the polygon mirror 4 is manufactured by cutting aluminum material, but this method is difficult to process, has low productivity, and is not preferable because the material is expensive.

One example of a solution to this problem is the Japanese Patent Application Publication No. 6
There is a device disclosed in Japanese Patent No. 1-59413.

In this method, a metal coating is formed on the outer circumferential surface of a polygonal base material made of resin to form a reflective surface, and a polygon mirror is easily and inexpensively manufactured.

Therefore, an optical deflector can be obtained by attaching the polygon mirror manufactured in this way to the drive shaft of a motor, but this optical deflector may have malfunctions such as eccentricity or tilting. Highly sexual.

In other words, in order for the optical deflector to perform precise optical scanning, each reflective surface must be highly parallel to the axis of the rotation axis of the polygon mirror, and the distance from the axis to each reflective surface must be constant. It must be. For this purpose, it is necessary that the joint between the polygon mirror and the rotating shaft be manufactured with high precision and high rigidity.

However, in the structure described above in which a polygon mirror made of synthetic resin is joined to a rotating shaft made of metal or the like, the accuracy and rigidity of this joint part tend to be low. Furthermore, since the polygon mirror made of synthetic resin and the rotating shaft made of metal or the like have large differences in coefficient of thermal expansion, there is a high possibility that these members will separate due to heat generation of the motor or the like.

Means for Solving the Problems The invention as set forth in claim 1 provides a rotating member having a conical shape with a tapered central portion protruding in the axial direction from a disk-shaped base and connected to a motor. A resin polygon mirror is provided surrounding the center of the member and fixed on the base.
An elastic member is provided that is attached to the center of the rotating member and presses the polygon mirror in the axial direction toward the base.

The invention according to claim 2 provides a rotating member having a central portion protruding from a disc-shaped base in the axial direction, the peripheral surface of which is provided with unevenness, and a motor is connected to the rotating member. A polygon mirror made of resin is fixed to the base board surface.

The invention according to claim 3 provides a rotating member having a locking member attached to the circumferential surface of a central portion protruding in the axial direction from a disk-shaped base and connected to a motor, and the central portion of the rotating member is connected to the rotating member. A polygon mirror made of resin is provided which encloses a locking member and is fixed on the base.

According to a fourth aspect of the present invention, a rotary member is provided in which a surface of a disk-shaped base is formed with irregularities to which a polygon mirror is fixed.

According to a fifth aspect of the invention, a heat insulating layer is provided between the polygon mirror and the rotating member.

The invention recited in claim 1 provides a rotary member having a tapered conical center portion protruding in the axial direction from a disc-shaped base and connected to a motor, and a rotary member surrounding the center portion of the rotary member. A resin polygon mirror is fixed on the base,
By providing an elastic member attached to the center of the rotating member to press the polygon mirror in the axial direction toward the base, the polygon mirror is pressed against the tapered joint surface that exists between it and the rotating member. Even if temperature changes occur in these members, the bonded state is maintained constant.

The invention according to claim 2 provides a rotating member having a central portion protruding from a disc-shaped base in the axial direction, the peripheral surface of which is provided with unevenness, and a motor is connected to the rotating member. By installing a resin polygon mirror fixed to the base plate surface, unevenness is formed on the joint surface between the polygon mirror and the rotating member, so that the joint between these parts is good and the polygon mirror is prevented from peeling off from the rotating member.

The invention according to claim 3 provides a rotating member having a locking member attached to the circumferential surface of a central portion protruding in the axial direction from a disk-shaped base and connected to a motor, and the central portion of the rotating member is connected to the rotating member. By providing a polygon mirror made of resin that encloses a locking member and is fixed on the base, the locking member fixed to the rotating member is located inside the polygon mirror, so it is protected against temperature changes, etc. Therefore, the polygon mirror is reliably prevented from peeling off from the rotating member.

The invention as claimed in claim 4 provides a rotating member having unevenness formed on the surface of the disk-shaped base to which the polygon mirror is fixed, so that the polygon mirror and the rotating member have different coefficients of thermal expansion due to being made of different materials. Even if the joint surface between the polygon mirror and the rotating member tends to separate due to temperature changes, the mating unevenness acts as a stopper and suppresses the difference in expansion between the two members. The bond between the two is maintained.

According to the fifth aspect of the invention, by providing a heat insulating layer between the polygon mirror and the rotating member, the heat generated by the motor is prevented from being conducted from the rotating member to the polygon mirror. The polygon mirror, which has a large coefficient of thermal expansion, is prevented from expanding and peeling off from the rotating member.

Embodiment First, an embodiment of the invention set forth in claim 1 will be described based on FIG. 1. Note that the same parts as in the conventional example described above are given the same names and numerals, and explanations thereof will be omitted. First, in the optical deflector l4 of this embodiment, the flywheel l6 fixed to the rotating shaft l5 is formed of a disk-shaped base l7 and a central part l8 projecting in the shape of a cone with a narrow upper part. Then, a polygon mirror l9 made of resin having a flat reflective surface formed by vapor-depositing a metal film on the outer circumferential surface surrounds the center portion l8 of the flywheel l6 and is attached to the Rjf base l7.
fixed on top. Therefore, the optical deflector l4 of this embodiment
Here, a leaf spring 20fJ, which is an elastic member attached to the upper end of the rotating shaft l5, presses the polygon mirror 19 against the flywheel l6 from above. In addition, in this optical deflector l4, the rotating shaft l5 and the flywheel l6 are integrally fixed, and both serve as rotating members.

In such a configuration, this optical deflector l4 functions similarly to the conventional optical deflector l.

Therefore, an example of a method for manufacturing the polygon mirror 19 made of resin as described above will be described below in the case where a photocurable resin is used as the resin material. First, an annular stopper member is fitted onto the outer peripheral surface of the flywheel l6, which is fixed in advance to the rotating shaft l5, and a polygonal space is formed by fitting a split mold inside the ring-shaped stopper member. Therefore, by curing the photocurable resin poured into this space with ultraviolet irradiation and removing the split mold and stopper member, a polygon mirror l9 integrally provided on the flywheel l6 can be obtained. . In addition to the above-mentioned photocurable resin, various resins can be used for the polygon mirror of the optical deflector of the present invention.

In addition, in this optical deflector l4, the central portion l8 is formed in a conical shape, so that the flywheel 16 and the polygon mirror 1
9 is tapered, and the polygon mirror 19 is pressed downward by the leaf spring 20 at the upper end of the rotating shaft 15, so that, for example, the polygon mirror 19 and the flywheel l6, which are originally fixed, Even if the two members tend to separate due to temperature changes or the like, the connection between these members is maintained by the elastic force of the leaf spring 20.

Further, in the optical deflector l4 of this embodiment, a polygon mirror l6 with a flat reflecting surface is assumed, but the present invention is not limited to the above structure. It is also possible to implement a curved surface such as (not shown). In this case, it becomes possible to correct the fθ characteristic using an optical system, which contributes to the production of a laser printer with a simple circuit configuration and high productivity.

Next, an embodiment of the invention set forth in claim 2 will be described based on FIG. 2. In this optical deflector 2l, an unevenness 25 is formed on the circumferential surface of a central portion 24 that protrudes in a cylindrical shape from a base 23 of a flywheel 22, which is a rotating member, and a polygon mirror 26 made of resin is fixed thereto. ing. Note that the other structure is similar to that of the optical deflector l4 described above.

With this configuration, in this optical deflector 2l, the unevenness 25 is formed in the center part 24 of the flywheel 22 to which the polygon mirror 26 is fixed, so that the bonding between these members is reliable and is resistant to temperature changes. The polygon mirror 26 is prevented from peeling off from the flywheel 22 due to aging or the like.

Furthermore, an embodiment of the invention according to claim 3 will be described based on FIG. In this optical deflector 27, a perforated disc 3l, which is a locking member, is attached to a rotating shaft 30, which is a central part that protrudes in the axial direction from a base 29 of a flywheel 28, which is a rotating member. It is located within a polygon mirror 32 made of resin.

In this configuration, in the optical deflector 27, the polygon mirror 32 includes the porous disk 3l fixed to the flywheel 28, so the polygon mirror 26 is not affected by temperature changes or aging. It is reliably prevented from peeling off from the flywheel 22.

A first embodiment of the invention set forth in claim 4 will be described based on FIG. In this optical deflector 33, a concave portion 36 which is an uneven surface is formed on the upper surface of a base portion 35 of a flywheel 34 which is a rotating member.
is formed, and a polygon mirror 37 made of resin is provided thereon. Note that the center portion 38 of the flywheel 34
is formed into a cylindrical shape or the like.

In this configuration, in this optical deflector 33, the concave portion 36 is formed on the base portion 35 of the flywheel 34, so that the joint between these members is good and the polygon mirror 3
7 is prevented from peeling off from the flywheel 34. In this optical deflector 33, even if the polygon mirror 37 and the center portion 38 of the flywheel 34, which have different coefficients of thermal expansion due to different materials, tend to separate due to temperature changes, the concave portion 36 remains stable. By acting as such, the difference in expansion between the two members 34 and 37 is suppressed, and the connection between the polygon mirror 37 and the central portion 38 is maintained.

Next, a second embodiment of the invention as set forth in claim 4 will be described based on FIG. In this optical deflector 39, an uneven convex portion 42 is formed on the upper surface of the base 4l of a flywheel 40, which is a rotating member, and a resin polygon mirror is formed on this convex portion 42.
43 are provided.

In such a configuration, this optical deflector 39 functions similarly to the optical deflector 33 described above.

In the optical deflector 39 of this embodiment, the convex portion 42 acting as a stopper is formed integrally with the flywheel 40, but the present invention is not limited to this, and for example, It is also possible to use a ring-shaped stopper member (not shown) screwed onto the upper surface of the base of the flywheel.

Furthermore, an embodiment of the invention set forth in claim 5 will be described based on FIG. 6. In the optical deflector 44 of this embodiment, a heat insulating layer 48 is formed on a disc-shaped base 46 and a cylindrical center part 47 of a flywheel 45, which is a rotating member, and a resin polygon mirror is formed on the heat-insulating layer 48. 49 is fixed.

In this structure, the optical deflector 44 includes a heat insulating layer 4 between the polygon mirror 49 and the flywheel 45.
8, the heat generated by a polygon motor (not shown) connected to the flywheel 45 via the rotating shaft 15 is not transmitted to the polygon mirror 49. Therefore, in this optical deflector 44, the polygon mirror 49, which has a large coefficient of thermal expansion, is prevented from expanding and peeling off from the flywheel 45 due to heat generated when the device is driven.

Effects of the Invention The invention as set forth in claim 1 provides a rotating member having a conical shape with a tapered center projecting in the axial direction from a disc-shaped base, and having a motor connected to the rotating member. A resin polygon mirror is attached to the base surrounding the
By providing an elastic member attached to the center of the rotating member to press the polygon mirror in the axial direction toward the base, the polygon mirror is pressed against the tapered joint surface that exists between it and the rotating member. , the bonded state is maintained constant even if a temperature change occurs in these members, and the invention according to claim 2 is characterized in that unevenness is formed on the circumferential surface of the central portion protruding from the disk-shaped base in the axial direction. By providing a rotating member to which a motor is connected, and providing a polygon mirror made of resin fixed to the circumferential surface of the central portion of this rotating member and the base board surface,
Since the unevenness is formed on the joint surface between the polygon mirror and the rotating member, the joint between these members is good and the polygon mirror is prevented from peeling off from the rotating member due to temperature changes, etc., and the invention according to claim 3 In this method, a rotating member is provided with a locking member attached to the circumferential surface of a central portion protruding in the axial direction from a disc-shaped base and a motor is connected to the rotating member, and the locking member is attached around the central portion of the rotating member. By providing a polygon mirror made of resin that is enclosed and fixed on the base, the locking member fixed to the co-rotating member is located inside the polygon mirror, so the polygon mirror does not change due to temperature changes, etc. The invention as claimed in claim 4 reliably prevents the polygon mirror from peeling off from the rotating member. Even if the joint surfaces between the polygon mirror and the rotating member, which have different coefficients of thermal expansion, tend to separate due to temperature changes, the mating unevenness acts as a stopper to suppress the difference in expansion between the two members. Therefore, the connection between the polygon mirror and the central part of the rotating member is maintained, and the invention according to claim 5 provides a heat insulating layer between the polygon mirror and the rotating member, thereby reducing the heat generated by the motor. Since conduction from the member to the polygon mirror is prevented, the polygon mirror, which has a large coefficient of thermal expansion, is prevented from expanding and peeling off from the rotating member due to the heat generated when the device is driven. Since it is possible to obtain an optical deflector with stable performance, the present invention has effects such as being able to contribute to the production of highly reliable optical scanning devices.

The figure is a longitudinal side view showing a second embodiment of the invention as claimed in claim 4, FIG. 6 is a longitudinal side view showing an embodiment of the invention as claimed in claim 5, and FIG. 7 is a perspective view showing a conventional example. FIG. 8 is a longitudinal side view.

14, 21, 27, 33, 39.44... optical deflector,
I 5, 16, 22, 28, 34, 40.45... Rotating member, 17, 23, 29, 35, 41.46... Base, 18, 24, 30, 38.47... Center part , 19
, 26, 32, 37, 43.49...polygon mirror
20... Elastic member, 25... Irregularities, 3l... Locking member, 36.42... Irregularities, 48... Heat insulating layer

[Brief explanation of drawings]

Claims (1)

[Scope of Claims] 1. A rotary member having a tapered conical central portion protruding in the axial direction from a disc-shaped base and connected to a motor is provided, and the central portion of the rotary member is surrounded by A light comprising: a polygon mirror made of resin fixed to the base; and an elastic member attached to the center of the rotating member to press the polygon mirror in the axial direction toward the base. Deflector. 2. A rotary member is provided which has a central part protruding from a disc-shaped base in the axial direction and has a concavity and convexity formed on the circumferential surface and is connected to a motor, and is fixed to the central part circumferential surface of the rotary member and the base plate surface. An optical deflector characterized by having a polygon mirror made of resin. 3. A rotating member is provided with a locking member attached to the circumferential surface of a central portion protruding in the axial direction from a disc-shaped base and a motor is connected thereto, and the locking member surrounds the central portion of the rotating member. What is claimed is: 1. An optical deflector comprising: a polygon mirror made of resin and fixed on the base; 4. The optical deflector according to claim 1, 2 or 3, further comprising a rotating member having a concavity and convexity formed on the surface of the disc-shaped base to which the polygon mirror is fixed. 5. An optical deflector comprising: a rotating member having at least a disc-shaped base and connected to a motor; and a resin polygon mirror provided on the base of the rotating member via a heat insulating layer.