JPH0642022B2 - Method for manufacturing polygon mirror - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method of manufacturing a polygonal mirror body in which a polygonal mirror body is rotated at a high speed to deflect a laser beam, and particularly to an optical recording device such as a laser printer. The present invention relates to a preferable method for manufacturing a rotor portion of a polygon mirror.

(Prior Art and Its Problems) A polygonal mirror has a rotating body in which a plurality of mirror-like bodies are formed on a side surface of a prismatic body having a regular octagonal cross section, for example, and the rotating body is rotated at a high speed by a small motor. Then, the mirror surface formed on the side surface of the mirror surface is irradiated with a laser beam subjected to image modulation, and an image is drawn by deflecting and scanning this beam, or conversely, the image is scanned with the laser beam, The image is read by the reflected light.

It is also used for such purposes as irradiating an object with a laser beam and measuring the size of the object by its shadow.

By the way, a polygonal mirror body which has been conventionally used is shown in FIG. In the figure, 1 is a case made of aluminum, which is formed in a cup shape, and has a shaft 2 in the center of the inside.
Is firmly erected. Inside the cup-shaped case 1, a plurality of stator coils 3, 3, 3, ... Are attached around the shaft 2 with an adhesive. A rotor body 5 made of aluminum is rotatably attached to the shaft 2 via two bearings 4. Inside the rotor body 5, a magnet 6 having a plurality of magnetic poles is fixed with an adhesive at a position facing the stator coil 3. Reference numeral 5a is a soft iron yoke member provided between the rotor body 5 and the magnet 6. On the upper surface of the rotor body 5, a mirror surface body 8 formed in an octagonal shape and provided with a mirror 7 on each side surface thereof is fixed by screws 9, 9.

In another conventional example, as shown in FIG. 10, a cup-shaped upper case 11 and a lower case 12 made of aluminum.
The substrate 13 is firmly held by the joint portion of the integrated case, and the bearing 1 is provided inside the upper case 11 and the lower case 12.
A shaft 16 is rotatably supported by 4 and 15. On the lower surface of the substrate 13, centering on the shaft 16,
A plurality of stator coils 17, 17, 17 ...
Is attached by an adhesive. A rotor body 18 is fixed to a lower end portion of the shaft 16, and a magnet 19 having a plurality of magnetic poles and a yoke member 18a having a plurality of magnetic poles at a position facing the stator coil 17 are attached to an upper portion of the rotor body 18 with an adhesive. It is fixed. The rotor body 18 is made of aluminum. At the upper end of the shaft 16, a mirror surface body 21 formed in an octagon and provided with a mirror 20 on each side surface thereof is fixed by a mirror mounting flange 24 fixed to the shaft 16 and screws 22, 22. An entrance / exit window 23 for a laser beam that enters the mirror 20 or is reflected from the mirror 20 is provided on the side surface of the upper case 11.

In the conventional device as described above, the mirror body is screwed directly to the rotor body 5, or is fixed to the mirror mounting flange fixed to the shaft 16 with screws,
The manufacturing process for assembling the polygon mirror is very troublesome.

Also, the polygon mirror needs to obtain a high-resolution image,
Further, since it is necessary to measure the precise dimensions, the mirror body requires a highly accurate assembly technique so that the mirror body does not have eccentricity and the mirror surface is not tilted.

The present invention is a novel invention that overcomes the above-mentioned conventional drawbacks, and an object thereof is to provide a method for manufacturing a polygonal mirror body which is small in size, simple in structure, and easy to assemble.

(Means for Solving Problems) In order to solve the above problems, the present invention provides a method for manufacturing a polygonal mirror body, which is a constituent element of a motor in which a rotor portion having a mirror is rotated by a motor. A) A concave portion for forming a field magnet portion is provided on the lower surface of a metallic disc-shaped material, and a penetrating portion for forming a bearing holding portion is provided in the central portion of the disc-shaped material, and the disc-shaped material is provided. A first step of forming a plastic magnet member holding portion of the field magnet forming portion in the step b), and b) after the first step, the recess, the bearing holding portion, and the plastic magnet holding portion are filled with the plastic magnet member and the central portion is formed. A step of forming a bearing holding part on the c), and c) a third step of forming a mirror on the side surface of the disc-shaped material after the second step. Method for manufacturing a polygonal mirror is provided.

Further, in the method of manufacturing a polygonal mirror body, which is a constituent element of a motor in which a rotor portion having a mirror is rotated by a motor, a) a concave portion for forming a field magnet portion on a lower surface of a metallic disc-shaped material and its A ring-shaped recess that forms a magnetic pole for detecting the position of the rotor is provided on the outer periphery, and a penetrating portion that forms a bearing holding portion is provided at the center of the disc-shaped material, and the disc-shaped material has a field magnet. A first step of forming the plastic magnet member holding portion of the forming portion; and b) a ring-shaped concave portion, a bearing holding portion, and a plastic forming a magnetic pole for detecting the position of the concave portion and the rotor after the first step. Filling the magnet holding portion with a plastic magnet member and forming a bearing holding portion in the center, and c) the side surface of the disc-shaped material after the second step. A third step of forming a mirror, the manufacturing method of the polygonal mirror having a provided.

(Operation) According to the present invention, a portion serving as a magnetic pole of a motor for rotating a mirror and a shaft insertion portion are formed on a metal disk-shaped material at once in an injection molding process of a plastic magnet member. At this time, the plastic magnet member is also filled in the plastic magnet member holding portion such as the hole or the undercut portion or the knurl portion of the disc-shaped material,
The rotor magnetic pole portion and the bearing holding portion of the motor are firmly held by the disc-shaped material, that is, the rotor portion. At this time, if a yoke member is sandwiched between the plastic magnet member and the disc-shaped material, this is also firmly held by the rotor portion.

In addition, in the invention, the portion for forming the magnetic pole for detecting the position of the rotor is simultaneously formed in the injection molding step.

(Example) Next, an example structure of a polygon mirror manufactured by the manufacturing method of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing a first embodiment of the present invention. In the figure, 31 is a base made of aluminum,
It is formed in a slightly thick disc shape, and an iron shaft 32 is erected at the center thereof. Reference numeral 33 denotes a stator-side yoke plate made of a ferromagnetic material such as a soft iron plate. Yoke plate 33
Is adhered onto the base 31 with an adhesive, and a terminal plate 33a is projected from the side. Therefore, the yoke plate 33
Has a "rice scoop shape". An insulating layer made of a thin synthetic resin film is provided on the upper surface of the yoke plate 33, or a synthetic resin such as an epoxy resin is applied to provide a thin insulating layer. Then, a predetermined printed wiring is formed thereon, and a printed board 34 is formed. The external connection terminal portion is provided on the terminal plate 33a. On the printed board 34, a plurality of stator coils 35 are attached in a circumferential shape around the shaft 32, and although not shown, those terminals are connected to the printed wiring on the printed board 34. To be done.

A rotor portion 37 is rotatably attached to the shaft 32 via two bearings 36. The rotor part 37 has a main part 37a made of aluminum and a central magnetizing part 37b. Magnetic poles are formed on the magnetized portion 37b for the rotor. Eight mirror bodies 3 are provided on the side surface of the main portion 37a.
7c is formed in an octagon. The magnetizing portion 37b serving as a field magnet forming portion is made of a plastic magnet member in which magnetic powder is mixed in synthetic resin, and is alternately arranged in a circumferential direction when viewed from the shaft 32 at a position facing the stator coil 35. The north and south poles are magnetized. Magnetizing part 37
A bearing holding portion 37d is formed of the same plastic magnet member as the magnetizing portion 37b on the center side of b. The outer race of the bearing 36 is fitted. Three
Reference numeral 8 denotes a yoke plate made of a soft iron plate. When the magnetized portion 37b is formed in the rotor portion 37 by injection molding, a circular cone opened from the child hole 38b formed in the yoke plate 38 to the upper surface of the rotor portion 37. It is fixed by a plastic magnet member overflowing the shaped hole 37e.

When a multi-phase alternating current generated by an inverter made of a semiconductor device is applied to the stator coil 35 of the polygon mirror configured as described above and a rotating magnetic field is generated in the circumferential direction around the shaft 32, the rotating magnetic field corresponds to this rotating magnetic field. Then, the magnetized portion 37b of the rotor portion 37 generates a rotational force between the magnetized portion 37b and the rotating magnetic field,
The rotor part 37 rotates. Reference numeral 39 is a position signal generator formed on the lower surface of the main portion 37a. The position signal generator 39
Is formed by filling a plastic magnet member in a shallow groove provided in a ring shape over the entire lower surface of the main portion 37a formed of aluminum and finely magnetizing the N pole and the S pole alternately. To be done. The position signal generator 3
The printed circuit board 34 on the lower side of the position signal generator 39
A detection unit 40 including a printed wiring formed in a zigzag shape corresponding to the magnetic poles magnetized in is provided. All of these detection units 40 are connected in series, and the rotor unit 3
When 7 rotates, the magnetic flux generated from the magnetic pole magnetized in the position signal generating unit 39 intersects the conductor made up of the printed wiring that constitutes the detecting unit 40, and the detecting unit 40 outputs a signal by this crossing and rotates. Detect the speed of the child. Although not shown in the figure, the signal detected by the detection unit 40 is sent to the control device and used as a rotation control signal for the rotor unit 37. Since these control methods are well known, detailed description will be omitted. When this polygon mirror is used in, for example, a laser printer, the mirror surface 37c of the rotating rotor unit 37 is irradiated with a modulated laser beam, which is scanned on the photosensitive drum to form a latent image on it. Form.

2 and 3 are a sectional view and a partially broken perspective view showing another example structure manufactured by using the manufacturing method of the present invention. This structure is almost the same as the previous example structure.
However, in the center of the rotor part 37, a shaft 32 that rotates together with the rotor part 37 is formed by a plastic magnet member instead of the bearing 36.
That is, it is press-fitted and fixed in the center of b. The rotor portion 37 is rotatably supported by the two bearings 36, 36 held by the cases 41, 42 shown in FIG. Since the operation of this polygon mirror is the same as that of the first polygon mirror, its explanation is omitted.

In this example structure, the shaft 32 is press-fitted and fixed after the magnetized portion 37b is injection molded, but the shaft 37 may be fixed to the magnetized portion 37b when the magnetized portion 37b is injection molded.

Next, the manufacturing method of the present invention will be described in detail with reference to the flow chart shown in FIG.

Referring to FIG. 4, first, in step (a), a blank 100 is prepared by cutting a blank aluminum into a disc shape.

In step (b), the upper surface of the material 100 is machined so that a reference surface is machined so that the rotation axis becomes vertical. Next, after the lower surface is subjected to surface processing, the magnetized portion 37b, the concave portion 101 to be the bearing holding portion 37d and the penetrating portion 106 are formed by boring, and the shallow concave portion 102 for forming the position signal generating portion 39 is formed on the lower surface. It is provided in a ring shape over the entire lower surface of the main portion 37a. Then, from the upper surface, the hollowed-out recess 101
8 small holes 103 having a conical shape in cross section are opened at even positions when viewed from the center.

Here, the manufacturing method according to the first embodiment and the manufacturing method according to the second embodiment are described. First, the manufacturing method according to the first embodiment will be described.

In step (c ₁ ), a ring-shaped yoke portion 38 is inserted into the bottom portion of the recess 101, the small hole formed therein is aligned with the portion 103, and then a plastic magnet member mixed with magnetic powder is attached. Recess 10 by injection molding method
1. Fill shallow recesses 102 and small holes 103. However,
The plastic magnet member is not filled in the through hole 104 portion into which the bearings 36, 36 are inserted. In this step, the yoke portion 38 does not use screws or adhesives,
It is fixed to the rotor part.

In step (d ₁ ), eight mirror surfaces 105 are formed on the entire side surface by high-speed cutting with reference to the reference surface-processed upper surface, and then, in step (e ₁ ), 2 are formed on the portion 104. The bearings are fitted together to form the rotor part.

Next, the manufacturing method of the second embodiment will be described.

In step (c ₂ ), a ring-shaped yoke portion 38 is inserted into the bottom portion of the recess 101, the small hole formed therein is aligned with the portion 103, and then a plastic magnet member mixed with magnetic powder is attached. Recess 10 by injection molding method
1. Fill shallow recesses 102 and small holes 103. However,
The plastic magnet member is not filled in the portion of the through hole 105 into which the shaft is inserted. In this process, the yoke part 3
8 is fixed to the rotor portion without using screws or adhesive.

In step (d ₂ ), eight mirror surfaces 105 are formed on the entire side surface by high-speed cutting with reference to the reference surface processed upper surface, and thereafter, in step (e ₂ ), the shaft is attached to the portion 105. Are fitted to form a rotor part.

In the present invention, the means for fixing the plastic magnet member to the rotor portion is not limited to filling the plastic magnet member into the hole 37e formed in the rotor 37 as in the above embodiment, and the following means are available. is there.

That is, for example, as shown in FIG.
The undercut portion 2 is formed in the upper part of the outer periphery of the recess 101 provided in the
00, or as shown in FIG.
Is provided with a knurl 300 on the outer peripheral portion thereof, or as shown in FIG. 7, the rotor 37 is provided with a hole 400 which does not penetrate the upper surface thereof, or
An undercut portion 500 is provided on the outer peripheral surface of the penetrating portion 106. Then, these undercut portions 200 or 5
00, knurling 300, hole 400, a plastic magnet member holding portion is filled with the plastic magnet member during the injection molding process, and the portion formed by the plastic magnet member is firmly fixed to the rotor portion. Is also possible.

(Effects of the Invention) As described in detail above, according to the first invention of the present application, a portion of a metal disk-shaped material that serves as a magnetic pole of a motor for rotating a mirror and a portion through which a shaft is inserted are made of a plastic magnet. Since it is formed at once in the injection molding process of the member, the manufacturing is simple, and since the plastic magnet member holding part consisting of holes etc. is filled with the plastic magnet member, the part formed by this plastic magnet member is rotated. It is firmly fixed to the child part without any assistance.

Further, in the invention, in addition to the effects of the invention described above, a portion for forming a magnetic pole for detecting the position of the rotor can be simultaneously formed in the injection molding step, which leads to simplification of the manufacturing process. .

[Brief description of drawings]

FIG. 1 is a sectional view showing a polygonal mirror body to which a first embodiment of the present invention is applied, FIG. 2 is a sectional view showing a polygonal mirror body to which a second embodiment of the present invention is applied, and FIG. A partially broken perspective view showing a polygonal mirror body to which a second embodiment of the invention is applied, FIG. 4 is a flow chart for explaining a manufacturing method of the present invention, and FIGS. 5 to 8 are other embodiments of the present invention. A sectional view showing an example, and FIGS. 9 and 10 are sectional views showing a conventional example. 31 ... Base, 32 ... Shaft, 33 ... Yoke plate,
35 ... Stator coil, 37 ... Rotor part, 37a ...
Main part, 37b ... Magnetizing part, 37c ... Mirror, 101 ...
… Recesses, 102 …… Recesses, 103 …… Small holes, 104 ……
Through hole 105: Mirror surface 106: Penetration part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Sumi Miyao 4-9-4 Chuorinkan, Yamato-shi, Kanagawa Shico Giken Co., Ltd.

Claims (16)

[Claims] 1. A method of manufacturing a polygonal mirror body, which is a constituent element of a motor in which a rotor portion having a mirror is rotated by a motor, comprising: a) a concave portion for forming a field magnet portion in a metal disk-shaped material. A first step of providing a penetrating portion for forming a bearing holding portion in the disc-shaped material and forming a plastic magnet member holding portion of the field magnet forming portion in the disc-shaped material; and b) the first step. After step 1, filling the plastic magnet member into the outer periphery of the penetrating portion forming the recess and the bearing holding portion and the plastic magnet member holding portion, and forming the bearing holding portion in the center, c) the second step And a third step of forming a mirror on the side surface of the disc-shaped material, the manufacturing method of the polygonal mirror body. 2. The method of manufacturing a polygonal mirror body according to claim 1, wherein the plastic magnet member holding portion is an inverted conical through hole that extends from the material concave portion to the material surface. . 3. The plastic magnet member holding portion is an inverted conical hole that does not penetrate from the material recessed portion to the upper surface of the disk-shaped material.
A method for manufacturing a polygonal mirror according to the item. 4. The polygon mirror body manufacturing method according to claim 1, wherein the plastic magnet member holding portion is an undercut portion provided in the upper part of the outer periphery of the concave portion provided in the material. Method. 5. The method for manufacturing a polygon mirror according to claim 1, wherein the plastic magnet member holding portion is a knurl provided on the outer periphery of a recess formed in the material. 6. The plastic magnet member holding portion is an undercut portion provided on an outer peripheral surface of a penetrating portion forming a bearing holding portion provided on the material, and the plastic magnet member holding portion is an undercut portion. Manufacturing method of polygon mirror body. 7. The polyhedral surface according to claim 1, wherein in step c), the bearing holding portion provided in the center of the material has a through hole into which a bearing for bearing the shaft is inserted. Mirror manufacturing method. 8. The method of manufacturing a polygon mirror according to claim 1, wherein in step c), the shaft is held by a bearing holding portion provided at the center of the material. . 9. A method of manufacturing a polygonal mirror body, which is a constituent element of a motor in which a rotor section having a mirror is rotated by a motor, comprising: a) a concave portion for forming a field magnet portion on a metal disk-shaped material. A ring-shaped recess that forms a magnetic pole for detecting the rotor position is provided on the outer periphery thereof, a penetrating portion that forms a bearing holding portion is provided in the disc-shaped material, and a field magnet forming portion is provided in the disc-shaped material. A first step of forming a plastic magnet member holding portion of the above, and b) a penetration through which a ring-shaped concave portion and a bearing holding portion that form a magnetic pole for detecting the position of the concave portion and the rotor are formed after the first step. Filling the outer circumference of the portion and the plastic magnet member holding portion with the plastic magnet member and forming a bearing holding portion in the center, and c) the disk after the second step. Method for manufacturing a polygonal mirror body and having a third step, forming a mirror on the side of the material. 10. The plastic magnet member holding portion comprises:
The method for manufacturing a polygonal mirror body according to claim (9), characterized in that the through-hole is an inverted conical through-hole that extends from the material recess to the surface of the material. 11. The plastic magnet member holding portion comprises:
The method for manufacturing a polygonal mirror body according to claim (9), characterized in that it is an inverted conical hole that does not penetrate from the material concave portion to the upper surface of the disk-shaped material. 12. The plastic magnet member holding portion comprises:
The method for manufacturing a polygonal mirror body according to claim (9), characterized in that the undercut portion is provided in the inner peripheral upper part of the recess provided in the material. 13. The plastic magnet member holding portion comprises:
The method for manufacturing a polygonal mirror according to claim (9), characterized in that it is a knurl provided on the outer circumference of a recess provided on the material. 14. The plastic magnet member holding portion comprises:
The method for manufacturing a polygonal mirror body according to claim (9), characterized in that it is an undercut portion provided on an outer peripheral surface of a penetrating portion forming a bearing holding portion provided on the material. 15. The polyhedral surface according to claim 9, wherein in the step c), the bearing holding portion provided in the center of the material has a through hole into which a bearing for bearing the shaft is inserted. Mirror manufacturing method. 16. The method for manufacturing a polygon mirror according to claim 9, wherein in step c), the shaft is held by the bearing holding portion provided in the center of the material. .