JPH04267214A - Axial mirror deflector - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

[Industrial Field of Application] The present invention is applicable to laser beam printers, digital copying machines, laser beam fax machines, barcode
The present invention relates to a light beam deflector used in a scanner, etc., and particularly to an axial mirror deflector.

0002

2. Description of the Related Art Conventionally, polygon scanners, hologram scanners, and galvanometric mirror scanners have been known as general optical beam deflectors. Also, recently, Japanese Patent Application Laid-Open No. 64-7015 and Japanese Patent Application Laid-Open No. 1-283512
As shown in the publication, a more compact axial mirror
Deflectors have been proposed.

JP-A-64-7015 discloses the basic structure of a deflector in which a shaft motor is provided on the rotor of the motor. Furthermore, Japanese Patent Application Laid-Open No. 1-283512 discloses a beam shaping aperture integrated with a motor flange, and the aperture is stationary with respect to the motor flange and mirrors. Rotate relative to a plane.

FIG. 12 shows the structure of a general axial mirror deflector.
and shown in FIG. The deflectors shown in FIGS. 12 and 13 both have a round shaft-shaped mirror mounted on the rotor of a surface-facing DC brushless motor with the center of the shaft aligned with the center of rotation of the rotor. . In the deflector shown in Fig. 12, a light beam is incident from the axial direction and is reflected by a mirror surface tilted at 45 degrees with respect to the rotation axis, so that the light beam is reflected as the rotor rotates. The reflected beam is deflected and scanned in a plane perpendicular to the axial direction. In the deflector shown in Fig. 13, two mirror surfaces are provided on the rotating shaft at right angles to each other, and a light beam incident from the rotating shaft direction is reflected in the rotating shaft direction by a reflecting surface different from the incident surface. A scanning beam is formed by another mirror member that is stationary with respect to the beam.

[0005]

In the deflectors of FIGS. 12 and 13, scanning is performed once and twice per revolution of the shaft, respectively. However, in the case of conventionally used polygon scanners, there are 6 to 10 mirrors.
It is normal to have a surface, and 6 to 10 per revolution of the shaft.
It is possible to perform multiple scans. In other words, in order to achieve the same performance as a polygon scanner with the deflector shown in Figure 12,
It is necessary to rotate the shaft 6 to 10 times faster. Figure 13
Even with this configuration, 3 to 5 times the speed is required. In practice, in the case of an axial mirror deflector, high speed rotation of 10,000 to 50,000 rpm is required.

On the other hand, in order to reduce the cost of parts, it is desired to use inexpensive glass or plastic as the material of the parts. Therefore, in the case of a shaft mirror deflector, it is conceivable to form a reflective surface on the surface of a shaft made of glass or plastic, for example, by vapor deposition of aluminum. However, as mentioned above, since the axial mirror deflector rotates at high speed, it is required to have great strength against centrifugal force. In other words, if glass or plastic is used for the shaft mirror deflector, it will not be strong enough, which may damage the shaft mirror or cause deflection of the shaft, causing a shift in the deflection position of the light beam. . For this reason and in connection with the inheritance of the conventional polygon mirror manufacturing technology, in the conventional axial mirror deflector, the mirror surface is formed by cutting an aluminum bar.

Therefore, in the present invention, the cost of the axial mirror deflector is reduced by using materials that are inexpensive or easy to process, and even when the shaft rotates at high speed, the axial mirror deflector is prevented from being damaged. The first problem is to prevent the occurrence of deflection, and the second problem is to eliminate the occurrence of deflection and the like to enable beam deflection with high positional accuracy.

[0008]

[Means for Solving the Problems] In order to solve the first problem, the present invention provides a shaft-like mirror deflector in which at least one reflective surface is formed on at least one end surface of a rotating shaft-like member. The shaft-like member is constituted by a shaft body and an exterior body that covers an outer circumferential surface of the shaft body, and the shaft body and the exterior body are constructed from materials different from each other.

[0009]

[Function] For example, if glass is used as the material of the shaft body, the cost of the material is low and it becomes easy to process the shape and form a mirror surface on the end face, so that the cost of the shaft mirror deflector can be reduced. Furthermore, since the outer circumferential surface of the shaft body is covered with the exterior body, even if easily breakable glass is used as the material for the shaft body, chipping and cracking can be prevented.

[0010] The above-mentioned chipping and cracking can be prevented even when aluminum, which has a longitudinal elastic modulus equivalent to that of glass, is used as the material for the outer casing, but in that case, the longitudinal elastic modulus of the shaft body and the outer casing are Since both are relatively small, the centrifugal force during high-speed rotation may cause deflection of the shaft, which may shift the position of the deflection beam.

[0011] Therefore, in a preferred embodiment of the present invention,
The exterior body is made of a material having a higher modulus of longitudinal elasticity than the material of the shaft body. For example, if the exterior body is made of steel with a large modulus of longitudinal elasticity, even if it is made of a relatively thin pipe-like member, deformation due to deflection of the shaft body can be reduced, and positional accuracy can be reduced. A high beam deflection is possible.

Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a shaft mirror deflector according to a first embodiment, and FIG. 2 shows a longitudinal section of a shaft member A of this shaft mirror deflector. As shown in FIG. 1, this shaft-like mirror deflector is composed of a shaft-like member A and an electric motor B that rotationally drives the shaft-like member A. As shown in FIG. 2, the shaft-like member A is composed of a cylindrical mirror base material 1 and a cylindrical exterior body 2 that covers the outer periphery of the mirror base material 1. As shown in FIG. One end surface 1a of the mirror base material 1 is a plane inclined at an angle of 45 degrees with respect to the axial direction, and a reflective mirror surface MR is formed on this plane. This reflective mirror surface MR is formed by depositing a reflective coating of metal (for example, aluminum or copper) on the surface 1a of the mirror base material 1. In this example, the mirror base material 1 is made of glass, and the exterior body 2 is formed by processing a steel pipe having a larger modulus of longitudinal elasticity. The purpose of covering the mirror base material 1 with the exterior body 2 is to prevent the mirror base material 1 from being damaged (chips, cracks, etc.) when rotating at high speed. When the mirror base material 1 is made of a material with a larger modulus of longitudinal elasticity, the exterior body 2
Even if the plate thickness is reduced, the amount of deformation of the mirror base material 1 due to centrifugal force can be reduced, and a decrease in deflection position accuracy can be prevented. A stepped portion 2a is formed on the outer periphery of the exterior body 2,
The base portion 2b has a small outer diameter. The outer diameter of the base portion 2b substantially matches the diameter of a reference hole 3a provided at the center of the rotor 3 connected to the drive shaft of the electric motor B. Therefore,
By fitting the base 2b to the rotor 3, the shaft-like member A and the electric motor B are integrated. Base 2b and low
In this example, the connection with the tab 3 is performed by press-fitting, but other methods such as adhesion or caulking may be used. Furthermore, in this example, the mirror base material 1 and the exterior body 2 are joined by shrink fitting, but other fixing methods for general shafts can be used, such as screwing or applying pressure in the radial direction. You may. Aluminum may also be used as the material for the exterior body 2, although the effect of suppressing the deformation of the mirror base material 1 is reduced. Further, for example, when plastic is used as the material of the mirror base material 1, the reflective mirror surface MR is formed by vapor deposition of metal, and the material of the exterior body 2 is a metal material such as aluminum or steel. The material 1 and the exterior body 2 may be integrated by outsert molding. Further, the mirror base material 1 may be formed from an aluminum bar, in which case the reflective mirror surface can be formed by polishing the end face. When the mirror base material 1 is made of aluminum, the exterior body 2 may be made of steel.

FIG. 3 shows a shaft member of a second embodiment, which is a modification of the first embodiment. That is, the present invention is applied to the configuration shown in FIG. 13, in which two reflective mirror surfaces MR1 and MR2 are formed on the upper surface of the mirror base material 4. 5 is the exterior body.

FIGS. 4 and 5 show a shaft member according to a third embodiment. In this example, the same exterior body 2 as in the first embodiment is used, but the mirror base material 8 has a slightly smaller diameter.
An adhesive layer 7 is provided between the mirror base material 8 and the exterior body 2. In other words, both are fixed with adhesive. In addition, two grooves 8a and 8 are provided along the axial direction on the outer peripheral surface of the mirror base material.
b is formed. These grooves form an escape route for excess adhesive and contribute to improving adhesive strength and adhesive reliability. Note that the same effect as an adhesive pool can be obtained by forming a knurling shape or roughening the surface in place of these grooves. As the adhesive, for example, epoxy adhesive or ultraviolet curing resin can be used.

FIGS. 6 and 7 show a shaft member according to a fourth embodiment. In this example, the mirror base material 9 is formed into a substantially quadrangular column shape, and the inner space of the exterior body 10 is also formed into a quadrangular column shape to match the shape. Furthermore, the ridgeline portion 9a of the square prism of the mirror base material 9 is chamfered, thereby forming an adhesive pool. In this example, the mirror
Since the base material 9 has a square prism shape, it is easy to process it to form the reflective mirror surface MR. In other words, when a large number of mirror base materials 9 are arranged so that their side surfaces touch each other, all the mirror surfaces have the same angle and height, so that all the mirror surfaces can be processed at once. Furthermore, if the outer shape of the shaft-like member is a square columnar shape, a large windage loss will occur when it rotates at high speed, but in this example, the outer shape of the exterior body 10 is a cylindrical shape. It can be prevented. Note that, since the portion of the exterior body 10 that contacts the corner of the mirror base material is thin, it may be necessary to build up the outer surface of that portion for reinforcement. In that case, although the exterior shape of the exterior body 10 is no longer circular, windage loss can be made smaller than in the case of a square column shape.

FIGS. 8 and 9 show a shaft member according to a fifth embodiment. In this embodiment, the exterior body 100 is a mirror base material 101.
The exterior body covers the mirror base material to a point considerably above the position of the reflective mirror surface MR. With this configuration, the strength of the exterior body 100 at the position of the reflective mirror surface MR is greater than in other examples,
The effect of preventing deflection of the mirror base material 101 is increased. However, since the exterior body 100 is located in the path of the reflected light,
An opening 100a is formed in that portion. Naturally, the smaller the size of the opening 100a, the smaller the size of the opening 100a.
The decrease in strength at 0 is also reduced.

FIG. 10 shows the overall structure of a shaft mirror deflector using the shaft member of the fifth embodiment. In this embodiment, the shaft member and the laser light source 11 are constructed to be integrated with the electric motor. Both ends of the exterior body 100 are rotatably supported by bearings 13A and 13B, respectively, and a rotor shaft 17 of an electric motor is fitted to the lower end of the exterior body 100. The force acting between the fixed electric coil 18 and the magnet 15 rotates the rotor 14 to which the magnet 15 is fixed, and the exterior body 100 and mirror base material 101 connected to the rotor 14 rotate. rotates. 12 is the motor housing (top), 16 is the motor housing (bottom), 19 is the screw, 20 is the light beam, 21 is C
The ring 22 is a printed circuit board. In addition, the exterior body 10
0 is further extended so that a portion thereof also serves as the rotor shaft 17, there is no need to provide a special rotor shaft.

FIG. 11 shows a sixth embodiment. This embodiment is designed to facilitate assembly and processing. That is, the exterior body 31 includes a cylindrical portion 31 that covers the mirror base material 30.
A and a plate-like portion 31b are provided, and a reinforcing rib 31c is further formed. Since the exterior body 31 and the rotor 32 are fixed by screws 33, assembly is easy.

[0020]

[Effects of the Invention] As described above, according to the present invention, the shaft body (
1, 4, 8, 9, 30, 101) and the exterior body (2, 5, 1
0, 31, 100) are made of different materials, the cost can be reduced by using a material that is inexpensive or easy to process, such as glass, for the shaft body, and when the shaft rotates at high speed. Also, damage to the shaft body can be prevented.

[0021] In particular, when the exterior body is made of a material with a higher modulus of longitudinal elasticity than the material of the shaft body, deflection in the shaft body can be eliminated and beam deflection with high positional accuracy can be obtained. .

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an axial mirror deflector of a first embodiment.

FIG. 2 is a longitudinal cross-sectional view showing the shaft-like member A of FIG. 1.

3 is a longitudinal sectional view showing a modification of the shaft-like member A of FIG. 2. FIG.

FIG. 4 is a plan view showing a shaft-like member of a third embodiment.

FIG. 5 is a longitudinal cross-sectional view showing a shaft-like member of a third embodiment.

FIG. 6 is a plan view showing a shaft-like member of a fourth embodiment.

FIG. 7 is a longitudinal cross-sectional view showing a shaft-like member of a fourth embodiment.

FIG. 8 is a perspective view showing a shaft-like member of a fifth embodiment.

FIG. 9 is a longitudinal sectional view showing a shaft-like member of a fifth embodiment.

FIG. 10 is a longitudinal sectional view showing the entire shaft mirror deflector of the fifth embodiment.

FIG. 11 is an exploded perspective view showing the shaft member and rotor of the sixth embodiment.

FIG. 12 is a perspective view showing a conventional example.

FIG. 13 is a perspective view showing a conventional example.

[Explanation of symbols]

1, 4, 8, 9, 30, 101: Mirror base material (shaft-shaped member) 2, 5, 10, 31, 100: Exterior body 3: Rotor 8a, 8b: Groove
11: Laser light source 12: Motor housing (upper) 13A, 13B
, 13C: Bearing 14, 32: Rotor 15: Magnet 16
: Motor housing (lower) 17: Rotor shaft 18: Electric coil 19,
33: Screw 20: Light beam 21: C ring
22: Printed circuit board 100a: Opening A: Shaft-shaped member
B: Electric motor MR: Reflective mirror surface

Claims (4)

[Claims] 1. A shaft-like mirror deflector in which at least one reflective surface is formed on at least one end surface of a rotating shaft-like member, wherein the shaft-like member is provided with a shaft body and an exterior covering that covers the outer peripheral surface of the shaft body. 1. A shaft-shaped mirror deflector, characterized in that the shaft body and the exterior body are made of different materials. 2. The shaft-shaped mirror deflector according to claim 1, wherein the exterior body is made of a material having a larger longitudinal elastic modulus than the material of the shaft body. 3. The shaft-shaped mirror deflector according to claim 1, wherein the shaft body is formed into a polygonal prism shape, and the outer peripheral shape of the exterior body is formed into a curved surface shape. 4. The shaft-like mirror according to claim 1, wherein a portion of the exterior body is formed with an opening through which the light beam reflected by the reflecting surface on the shaft body passes. Deflector.