JPH08190064A - Optical scanner - Google Patents

Abstract

PURPOSE: To reduce the number of parts of a supporting mechanism for a rotary polygon mirror in a rotary shaft by fitting the rotary polygon mirror to a rotary member between an engaging part of one end side of the rotary member and a receiving member of another end side, engaging an inside projection part of an elastic member with the engaging part and pressing the rotary polygon mirror to the receiving member by an outside projection part. CONSTITUTION: The rotary shaft 2 is exposed from a housing case 3 to the outside, and a recessed part 4 being the engaging part is formed near the top end of the shaft 3. Further, the rotary polygon mirror 6 is fitted to the rotary shaft 2 so as o be come into contact with the upper surface of the receiving member 5. By fitting a part projecting inward among a curve part of an elastic wire rod 7 being the elastic member to the recessed part 4 provided on the rotary shaft 2 is the state pushing and spreading the part, the elastic wire rod 7 is held by the rotary shaft 2 with the elastic force of the elastic wire rod 7. Simultaneously, the part projecting outward in the elastic wire rod 7 is pushed to the upper part of the rotary polygon mirror 6, so that the rotary polygon mirror 6 is pressed on the receiving member 5 by the elastic force of the elastic wire rod 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical scanning device using a rotary polygon mirror in a laser beam printer or the like, and more particularly to a mechanism for holding the rotary polygon mirror with respect to a rotary shaft.

[0002]

2. Description of the Related Art Conventionally, as an optical scanning device, a mechanism for rotating a rotary polygon mirror at high speed has been known. In such an apparatus, since it is necessary to scan light with high precision, it is necessary to hold the rotary polygon mirror so that the rotary polygon mirror does not tilt with respect to the rotation axis. Therefore, various means have heretofore been disclosed as means for holding the rotary polygon mirror on the rotary shaft.

As an example thereof, a light beam scanning device as disclosed in Japanese Utility Model Publication No. 3-2887 has been proposed. According to this device, as shown in FIG. 10, the rotary polygon mirror 22 is held on the rotary shaft 21 by the following means. That is, the pressing ring 23 inserted in the rotary shaft 21,
The compression spring 24, which is an elastic body, is pressed by a locking member 25 such as an E ring. Due to the elastic force of the compression spring 24, the rotary polygon mirror 22 can be pressed against the receiving member 26 arranged orthogonal to the rotary shaft 21. This allows
It is possible to hold the rotary polygon mirror 22 with respect to the rotary shaft 21 so as not to tilt.

[0004] As another example, the actual Kaihei 3-661.
A light beam scanning device as disclosed in Japanese Patent No. 8 has been proposed. According to this device, as shown in FIGS. 11 and 12, the rotary polygon mirror 28 is attached to the rotary shaft 27 by the holding member 2.
9 is held by the following means. That is, the restraining member 29 is a disc-shaped elastic body having a central inner diameter portion hole diameter smaller than the diameter of the rotating shaft 27 and having a plurality of splits in the radial direction. The holding member 29 is pushed from above the rotary shaft 27 so that the rotary shaft 27 is hard to fit and is locked. This makes it possible to hold the rotary polygon mirror 28 with respect to the rotary shaft 27 so that there is no surface tilt.

[0005]

However, the holding mechanism in the above conventional device has the following problems.

That is, in the light beam scanning device as disclosed in Japanese Utility Model Publication No. 3-2887, at least two parts, that is, a compression spring which is an elastic body and an E ring which is a locking member, are required as a part structure. . Further, in order to apply a uniform pressing force to the rotary polygon mirror, it is necessary to insert a holding ring such as a washer between the compression spring and the rotary polygon mirror. Such an increase in the number of parts causes not only an increase in the cost of parts but also an increase in the number of assembling steps, resulting in an increase in the assembling cost.

Further, in the light beam scanning device as disclosed in Japanese Utility Model Laid-Open No. 3-6618, the number of parts and the number of assembling steps are minimized, but there are the following problems. That is, when the pressing member is engaged with and locked to the rotating shaft, a trace is generated on the rotating shaft. For this reason, in order to remove the rotary polygon mirror after it is once locked, it is necessary to destroy the holding member, and it is difficult to remove the rotary polygon mirror due to the traces left on the rotary shaft. Furthermore, when the rotary polygon mirror is mounted and locked again, it is difficult to reliably hold the rotary polygon mirror due to the traces left on the rotary shaft.

Further, in this conventional device, since the holding member is pushed and locked from above the rotary shaft, a large load is applied to the rotary shaft at that time, and the bearing member of the rotary shaft is deformed. There is a risk that it may be damaged or that the surface of the rotating polygon mirror may be tilted or that rotation may be defective.

The present invention has been made to solve the above-mentioned problems, and provides an inexpensive optical scanning device by reducing the number of parts used for a holding mechanism of a rotary polygon mirror on a rotary shaft. The purpose is to do. Another object of the present invention is to facilitate the attachment / detachment of the rotary polygon mirror to / from the rotary shaft in the optical scanning device, and to reduce the load on the rotary shaft when mounting the rotary polygon mirror. Another object of the present invention is to provide a highly reliable optical scanning device that prevents deformation and damage to the bearing parts and the like.

[0010]

In order to achieve this object, an optical scanning device according to claim 1 of the present invention is provided with a rotary member rotatable by a rotary drive means and one end side of the rotary member. The engaging part and the other end of the rotating member are provided,
A receiving member having a surface orthogonal to the rotation axis of the rotating member, a rotary polygonal mirror fitted between the engaging portion and the receiving member on the rotating member, and a plurality of inner protrusions engaging with the engaging portion. And an elastic member formed of a single member having a plurality of outer protruding portions that press the rotary polygon mirror against the receiving member, and the inner protruding portion and the outer protruding portion of the elastic member in the rotation axis direction. It has a height difference.

In the optical scanning device according to the second aspect, the height difference of the elastic member is made larger than that between the engaging portion and the rotary polygon mirror.

In the optical scanning device according to the third aspect, the elastic member is formed of a metal material, a part of which is open to the outside.

Further, in the optical scanning device according to the fourth aspect, the elastic member is formed of a resin forming member having a continuous closed shape.

Further, in the optical scanning device according to a fifth aspect of the present invention, the engaging portion is a recess formed in the rotating member, and the elastic member has a diameter of an imaginary circle formed by a plurality of inner protruding portions, and a diameter of the rotating member. It is formed to be smaller.

[0015]

In the optical scanning device according to the first aspect of the present invention having the above structure, the rotary polygon mirror is fitted to the rotary member between the engaging portion on one end side of the rotary member and the receiving member on the other end side. The plurality of inner protrusions of the elastic member engage with the engaging portion, and the plurality of outer protrusions press the rotary polygon mirror against the receiving member.

In the optical scanning device according to the second aspect of the invention, the elastic member having a larger height difference between the engaging portion and the rotary polygon mirror presses the rotary polygon mirror against the receiving member.

In the optical scanning device according to the third aspect, the elastic member made of a metallic material, a part of which is open to the outside, is attached to the rotating member.

Further, in the optical scanning device according to the fourth aspect, the elastic member, which is a resin molding member having a continuous closed shape as a whole, is attached to the rotating member.

Further, in the optical scanning device according to the fifth aspect, the engaging portion is formed of the concave portion, and the plurality of inner protruding portions having virtual circles having a diameter smaller than the diameter of the rotating member surely engage with the concave portion. .

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

First, with reference to FIG. 1 to FIG. 3, a structure in which a linear member having elastic force is used as the elastic member will be described.

The output end of the drive motor 1 which is the rotation drive means is a rotating shaft 2 as a rotating member, and the drive motor 1 is housed in a housing case 3. Rotating shaft 2
Is exposed from the storage case 3 to the outside, and a recess 4 as an engaging portion is formed near the tip of the storage case 3. An annular receiving member 5 is inserted into the rotating shaft 2 exposed from the storage case 3, and the upper surface of the receiving member 5 is arranged so as to be orthogonal to the rotation axis of the rotating shaft 2.

Further, a rotary polygon mirror 6 is fitted on the rotary shaft 2 so as to come into contact with the upper surface of the receiving member 5. The rotary polygon mirror 6 has a mirror-finished side surface.

The elastic wire 7 which is an elastic member is shown in FIG.
As shown in, a wire made of a metal material is cut into a predetermined length and then bent, and is composed of a plurality of curved portions. The curved portion has six inner protruding portions 8 protruding inward and six outer protruding portions 10 protruding outward.

The diameter of the imaginary circle 9 formed by the inner protruding portion 8 is smaller than the diameter of the concave portion 4 provided on the rotary shaft 2. Thereby, the elastic wire 7 can be firmly engaged with the recess 4.
The diameter of the imaginary circle 9 does not necessarily have to be smaller than the diameter of the concave portion 4, but may be smaller than the diameter of the rotating shaft 2.

Further, one of the six outer protrusions 10 is configured to open the outer protrusion 10a to the outside. The elastic wire 7 can be smoothly engaged with the recess 4 from this portion.

Further, the inner protruding portion 8 and the outer protruding portion 10 have a height difference in the axial direction of the rotary shaft 2 as shown in FIGS. 2 and 3B. The height difference is configured to be larger than the distance between the concave portion 4 and the upper surface of the rotary polygonal mirror 6, whereby the rotary polygonal mirror 6 is formed.
The receiving member 5 can be pressed firmly.

Then, in the curved portion of the elastic wire rod 7, by fitting the portion 8 protruding inwardly into the recessed portion 4 provided in the rotary shaft 2 in a state of being expanded, the elastic force of the elastic wire rod 7 causes the elastic wire rod 7 to move. 7 is held on the rotary shaft 2. at the same time,
A portion 10 of the elastic wire rod 7 that protrudes to the outside is a rotary polygon mirror 6
The rotary polygon mirror 6 is pressed against the receiving member 5 by the elastic force of the elastic member 7 by being pressed against the upper part of the. With such a configuration, the rotary shaft 2 and the rotary polygon mirror 6 are held while the rotary polygon mirror 6 is pressed against the receiving member 5. Receiving member 5
Is arranged orthogonally to the rotary shaft 2, so that the rotary polygon mirror 5 does not tilt with respect to the rotary shaft 2 and performs a highly accurate rotary motion.

As described above, according to the present embodiment, by bending the single elastic wire 7, the inner protrusion 8 that engages with the rotating shaft 2 and the outer protrusion 10 that presses the rotary polygon mirror 6 are formed.
Since and are formed, the configuration can be simple.

Next, with reference to FIG. 4 and FIG. 5, the structure when the plate-like member 11 having elastic force is used as the elastic member will be described.

As shown in FIG. 4, the main structure is the same as that of the above-mentioned embodiment, and therefore its explanation is omitted.

The elastic plate member 11 which is an elastic member is shown in FIG.
As shown in (a), a plate material made of a metal material is processed by pressing or the like, and is composed of a plurality of curved portions. Among the curved portions, six inner protruding portions 12 protruding inward are formed and six outer protruding portions 14 protruding outward are formed.

The diameter of the imaginary circle 13 formed by the inner protruding portion 8 is smaller than the diameter of the concave portion 4 provided in the rotary shaft 2. Part 1 protruding further inward
2 and the portion 14 protruding to the outside have a shape having a difference in height as shown in a virtual sectional view of a part of the cross section shown in FIG. 5B.

Of the curved portion of the elastic plate member 11, the inner protruding portion 12 is expanded and fitted into the concave portion 4 provided in the rotating shaft 2, so that the elastic plate member 11 is elastically moved by the elastic force of the elastic plate member 11. Held at 2. At the same time, the portion 14 protruding to the outside of the elastic plate member 11 is pressed against the upper part of the rotary polygonal mirror 6, and the elastic force of the elastic plate member 11 presses the rotary polygonal mirror 6 against the receiving member 5. Hereinafter, the obtained actions and the like are as described above.

The present invention is not limited to the embodiments described above in detail, and various modifications can be made without departing from the spirit of the invention.

For example, in the first embodiment, the elastic wire rod 7 has six inner protrusions 8 and six outer protrusions 1, respectively.
However, as shown in FIGS. 6 and 7, the elastic wire 7 may be formed of three inner protrusions 8 and three outer protrusions 10, respectively. Further, it goes without saying that the shape of the elastic member does not necessarily have to be the shape in which the petals are spread as described above, and may be any shape as long as a uniform pressing force can be obtained. Further, in this embodiment, one of the three inner projecting portions 8 is open to the outside, but the position of opening to the outside may be appropriately provided.

Next, as shown in FIGS. 8 and 9, the elastic wire 7 may be continuously closed. In this case, the elastic wire 7 is made of a relatively soft metal material, synthetic resin, or the like, and the whole is pulled and expanded.
It is engaged with the recess 4 of the rotary shaft 2. Then, the elastic plate member 7 configured as described above is displaced and the recess 4 of the rotary shaft 2 is moved.
It is also possible to increase the pressing force of the rotary polygon mirror 6 to the receiving member 5 by attaching a plurality of them to the receiving member 5.

Further, the elastic plate member 11 as shown in FIG. 5 is made of synthetic resin, or the outer open position of the elastic plate member 11 shown in FIG. 5 is provided on the inner protruding portion as shown in FIG. It is possible to take various configurations such as a combination of the embodiments.

In any of the embodiments, the material cost and the processing cost can be reduced.

[0040]

As is apparent from the above description, according to the optical scanning device of the present invention, since no trace is left on the rotary shaft, the rotary polygon mirror can be easily attached to and detached from the rotary shaft.
Further, since the load applied to the rotary shaft when the rotary polygon mirror is mounted can be reduced, the bearing components of the rotary shaft are not deformed or damaged, so that a highly reliable optical scanning device can be provided.

Furthermore, since the number of parts used for the holding mechanism of the rotary polygonal mirror on the rotary shaft can be reduced, the parts cost and the assembly cost can be reduced, so that an inexpensive optical scanning device is provided. It has a significant industrial effect.

[Brief description of drawings]

FIG. 1 is a perspective view showing the configuration of an optical scanning device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of an optical scanning device of this embodiment.

FIG. 3A is a top view showing an elastic wire used in the optical scanning device of the present embodiment. (B) It is a side view of the said elastic wire.

FIG. 4 is a perspective view showing a configuration of an optical scanning device according to another embodiment of the present invention.

FIG. 5A is a top view showing an elastic plate member used in the optical scanning device of another embodiment. (B) It is a side view of the said elastic plate material.

FIG. 6 is a perspective view showing a configuration of an optical scanning device of a modified example of the invention.

FIG. 7A is a top view showing an elastic wire used in an optical scanning device of a modified example. (B) It is a side view of the said elastic wire.

FIG. 8 is a perspective view showing a configuration of an optical scanning device according to another modification of the present invention.

FIG. 9A is a top view showing an elastic wire used in an optical scanning device of another modification. (B) It is a side view of the said elastic wire.

FIG. 10 is a sectional view showing an example of a conventional optical scanning device.

FIG. 11 is a sectional view showing an example of a conventional optical scanning device.

FIG. 12A is a sectional view of a holding member used in a conventional optical scanning device. (B) It is a top view of the said pressing member.

[Explanation of reference numerals] 1 drive motor 2 rotating shaft 3 storage case 4 recess 5 receiving member 6 rotating polygon mirror 7 elastic wire rod 8 inner protruding portion 10 outer protruding portion 11 elastic plate member 12 inner protruding portion 14 outer protruding portion

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Susumu Ito 15-1 Naeshiro-cho, Mizuho-ku, Nagoya City Brother Industries, Ltd.

Claims (5)

[Claims] 1. A rotating member rotatable by a rotation driving means, an engaging portion provided on one end side of the rotating member, and an engaging portion provided on the other end side of the rotating member and orthogonal to a rotation axis of the rotating member. A receiving member having a surface for rotating, a rotary polygon mirror fitted to the rotating member between the engaging portion and the receiving member, a plurality of inner protruding portions engaging with the engaging portion, and the rotating polygon mirror An elastic member formed of a single member having a plurality of outer protruding portions that press against the receiving member, and the inner protruding portion and the outer protruding portion of the elastic member have a height difference in the rotation axis direction. An optical scanning device having. 2. The optical scanning device according to claim 1, wherein the height difference of the elastic member is larger than that between the engaging portion and the rotary polygon mirror. 3. The optical scanning device according to claim 1, wherein the elastic member is a metal material formed so that a part thereof is open to the outside. 4. The optical scanning device according to claim 1, wherein the elastic member is a resin molding member having a continuous closed shape. 5. The engagement portion is a recess formed in the rotating member, and the elastic member is configured such that a diameter of an imaginary circle formed by the plurality of inner protruding portions is smaller than a diameter of the rotating member. The optical scanning device according to claim 1, wherein the optical scanning device is formed in