JPH04258525A - Light deflection device - Google Patents

Abstract

PURPOSE:To provide a light deflection device capable of reducing the number of parts and the manufacturing cost by forming a shaft, a mirror and a rotor in one unit. CONSTITUTION:A rotor 10 is formed in a shaft shape and a section thereof is a rotor magnet (first multielectrode magnet) 11 having N pole and S pole formed alternately in a multielectrode manner. Also a pyramidal mirror composed on the whole surface of the mirror is formed on the tip of one end of the rotor 12 as a deflection mirror 12.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical deflection device used in a scanning optical system of a laser beam printer, a digital facsimile machine, a digital copying machine, etc., and more particularly to a motor structure and a bearing structure of the optical deflection device.

0002

2. Description of the Related Art Conventionally, a laser beam printer forms a two-dimensional image on a photoreceptor drum by scanning the photoreceptor drum in one dimension with a laser beam and rotating the photoreceptor drum. 2. Description of the Related Art In order to scan a laser beam in a one-dimensional direction, an optical deflection device using a deflection mirror is often used. When the deflection mirror rotates, for example, if the mirror has one surface, the laser beam is deflected and scanned at a rate of one beam per rotation.

In recent years, information processing apparatuses such as laser beam printers have become more dense and faster in processing information, and at the same time, the main body of the apparatus has also been made smaller and lighter. Regarding higher density, in order to form a high-resolution image on a photoreceptor drum, it is necessary to increase the density of scanning lines, that is, deflected light. Moreover, in order to increase the printing speed,
It is necessary to increase the rotation speed of the deflection mirror, increase the number of mirror surfaces, or increase the diameter of the deflection mirror.

[0004] Considering miniaturization and weight reduction, it is desirable to have an optical deflection device in which the deflection mirror is made small and rotates at high speed. In response to such requests, instead of using a general polygon mirror as a deflection mirror, we have developed a pyramidal mirror, V
There are some that have been made smaller using molded mirrors, mortise-shaped mirrors, etc. In addition, an optical deflection device that aims to reduce the size and improve accuracy by integrating the magnet rotor of the motor and the polygon mirror, for example,
It is disclosed in JP-A No. 197010, Japanese Unexamined Patent Application Publication No. 62-295017, and the like.

[0005]

[Problems to be Solved by the Invention] However, in such conventional optical deflection devices that use pyramidal mirrors, etc., the mirror part is integrated by integrating the shaft itself, which is the rotation axis. However, the rotor, which serves as the drive unit, was not sufficiently miniaturized.

Furthermore, in the case where the magnet rotor and the polygon mirror are integrated, the polygon mirror itself is larger than the pyramidal mirror, making it difficult to downsize the mirror including the motor section. Furthermore, the biggest problem when rotating a rotating body at high speed is the bearing structure that supports the rotating body. In conventional bearing structures, the rotating body is firmly directed by a geometric center axis, and unbalance is dealt with by a technique called balance correction. Conventional bearing structures of this type include: ■ Supported by a hydrodynamic bearing with a spiral groove, ■ Supported by a ball bearing for a wide range of general purposes, ■ Supported by magnetic fluid, and ■ Supported by a magnetic circuit. Active magnetic bearings that monitor and support rotational conditions.
etc.

However, regarding item (2), the manufacturing cost of the spiral groove is high, and since no dynamic pressure is generated when the machine is stopped, there is a risk that the bearing parts may come into contact with each other, causing scratches, dirt, etc. Also, regarding ■, the number of times of Pyramidal Mirror is tens of thousands of rp
Since the bearing grease reaches a maximum of m, it has no lifespan and cannot be used. Next, regarding (2), the viscosity changes significantly with respect to temperature, and when designing the motor, a margin must be increased, resulting in an increase in the size of the motor. Furthermore, a bearing seal is also required, resulting in a complex structure and high cost. Finally, regarding ■, although it is suitable for non-contact and high-speed rotation,
Since it requires a sensor to monitor the status of the shaft, an electromagnet to support the shaft, and a control circuit, it is large and expensive and is not suitable for commercial-grade products.

[0008] Accordingly, an object of the invention as set forth in claim 1 is to provide an optical deflection device that can reduce the number of parts and reduce costs by integrally forming a shaft, a mirror, and a rotor. In addition, the invention according to claim 2 uses a manganese-aluminum-carbon alloy as a magnet material, thereby making it possible to mirror-finish a deflection mirror that requires high reflectance, and having excellent strength when used as a shaft. The purpose is to provide a rotor whose magnetic properties do not deteriorate.

Another object of the invention is to provide a compact optical deflection device by using a pyramidal mirror as a deflection mirror. Also, claim 4
An object of the described invention is to provide an optical deflection device that can control the rotational speed of a rotor by detecting magnetic changes in the rotating rotor as changes in frequency.

Another object of the invention is to provide a pair of magnetic bearings that do not require electrical control by arranging permanent magnets with the same magnetic poles facing each other. Further, the invention as claimed in claim 6 provides an optical system that can magnetically levitate the shaft and restrain the movement of the shaft in both thrust and radial directions by making the bearing surface of the magnetic bearing a conical side wall surface symmetrical with respect to the axis. The purpose is to provide a deflection device.

[0011] Furthermore, in the invention as set forth in claim 7, a viscoelastic body interposed between the annular magnet in the magnetic bearing and the motor housing serving as the main body of the device causes the vibration of the rotor during rotation to act as a reaction to the magnetic force of the motor. It is an object of the present invention to provide a light deflection device that can reduce the degree of light transmitted to the housing side. Furthermore, an object of the invention as set forth in claim 8 is to provide an optical deflection device that can completely restrain the movement of a rotor in the thrust direction by sandwiching a single magnetic pole portion between annular magnets from above and below in the axial direction. There is.

0012

[Means for solving the problem] The invention according to claim 1 includes:
In order to achieve the above object, in an optical deflection device, the rotor is connected to a shaft. It is characterized in that it is formed into a shape, and a deflection mirror is formed at the tip on one end side of the rotor.

In order to achieve the above object, the invention as set forth in claim 2 is characterized in that the rotor is formed of a magnet made of a manganese-aluminum-carbon alloy. Further, in order to achieve the above object, the invention according to claim 3 is characterized in that the deflection mirror is a pyramidal mirror.

[0014] Furthermore, in order to achieve the above object, the invention according to claim 4 provides a second multipolar magnet having a number of poles larger than the number of poles of the first multipolar magnet formed as a rotor. is formed on the rotor, and a magnetic sensor for detecting magnetic changes during rotation is disposed at a position facing the second multipolar magnet. In addition, in order to achieve the above object, the invention according to claim 5 provides a single magnetic pole part in the circumferential direction of the rotor, and annular magnets having the same magnetic pole as the single magnetic pole part are separated by a predetermined distance and are opposed to each other. This arrangement is characterized by forming a pair of magnetic bearings.

Further, in order to achieve the above object, the invention according to claim 6 includes a rotor driven by an electromagnetic coil, a shaft serving as a rotation axis of the rotor, and a shaft that rotates together with the shaft to rotate incident light. and a deflection mirror that reflects and deflects the shaft, a single magnetic pole portion having a conical side wall surface symmetrical with respect to the axis of the shaft and having a single magnetic pole on the conical side wall surface is provided. At the same time, a pair of magnetic bearings are formed by arranging annular magnets having an inclined surface parallel to the conical side wall surface of the single magnetic pole part and facing each other with a predetermined distance between them and having the inclined surface having the same magnetic pole as the conical side wall surface. It is characterized by the fact that

[0016] Furthermore, the invention as set forth in claim 7 is characterized in that, in order to achieve the above object, the annular magnet in the magnetic bearing is joined to the motor housing serving as the main body of the device via a viscoelastic body. . In addition, in order to achieve the above object, the invention according to claim 8 forms two conical side wall surfaces of the single magnetic pole portion facing toward the axial end of the shaft, and an annular magnet is formed so as to face each conical side wall surface. It is characterized by the arrangement of.

[0017]

In the invention as set forth in claim 1 having the above structure, the rotor, the shaft, and the deflection mirror are integrally formed. Moreover, in the invention according to claim 2 having the above-mentioned configuration, the rotor is formed by a magnet made of a manganese-aluminum-carbon alloy.

Further, in the invention according to claim 3 having the above configuration, the deflection mirror is a pyramidal mirror. Further, in the invention according to claim 4 having the above configuration, a second multipolar magnet having a number of poles larger than the number of poles of the first multipolar magnet formed as the rotor is formed on the rotor. A magnetic sensor placed opposite the second multipolar magnet detects magnetic changes during rotation.

Further, in the invention according to claim 5 having the above configuration, a single magnetic pole portion is provided in the circumferential direction of the rotor,
A pair of magnetic bearings is formed by arranging annular magnets having the same magnetic pole as this single magnetic pole part and facing each other with a predetermined separation. Further, in the invention according to claim 6 having the above configuration, a single magnetic pole part is provided which has a conical side wall surface symmetrical with respect to the axis of the shaft and has a single magnetic pole on the conical side wall surface, and A pair of magnetic bearings is formed by arranging annular magnets having an inclined surface parallel to the conical side wall surface of the single magnetic pole part and facing each other with a predetermined distance between them and the inclined surface having the same magnetic pole as the conical side wall surface.

Furthermore, in the seventh aspect of the invention having the above configuration, the annular magnet in the magnetic bearing and the motor housing serving as the main body of the device are joined via a viscoelastic body. Further, in the invention as set forth in claim 8 having the above configuration, two conical side wall surfaces of the single magnetic pole part are formed facing toward the axial end of the shaft, and an annular magnet is arranged to face each conical side wall surface. .

[0021]

EXAMPLES The present invention will be explained below based on examples. FIG. 1 is a side sectional view showing an optical deflection device according to an embodiment of the invention according to any one of claims 1 to 3. In Figure 1,
The rotor 10 is formed into a shaft shape, and a part of the rotor 10 is a rotor magnet (first multipolar magnet) 11 having a multipolar structure in which north and south poles are alternately formed in the circumferential direction. Furthermore, a one-sided pyramidal mirror is formed as a deflection mirror 12 at the tip of one end of the rotor 10 . The rotor magnet 1
An electromagnetic coil 14 for driving the rotor magnet 11 is provided on the inner periphery of the motor housing 13 facing the rotor magnet 1.
This electromagnetic coil 14 is composed of a stator 15 serving as a stator and a coil 16 wound around the stator 15. Further, a spiral groove 17 is formed in a part of the rotor 10, and the rotor 10 is supported by an air bearing part 18 as a dynamic pressure bearing formed by the surface of the motor housing 13 facing the spiral groove 17. has been done. In the optical deflection device configured as described above, the deflection mirror 12
The laser beam L incident from directly above is deflected and scanned at a rate of one beam per rotation.

[0022] Here, in the optical deflection device according to the invention as claimed in claim 1, the number of parts is reduced from three to one by integrating the shaft, mirror, and rotor to form the rotor 10. , it is possible to achieve improved accuracy and miniaturization through integration, and to reduce costs. By the way, in this embodiment, since the rotor 10 is used as a shaft,
The shaft itself is formed by a magnet, but the magnet used here is used when mirror-finishing the deflection mirror 1.
It must guarantee the reflection efficiency at 2.

Therefore, in the optical deflection device according to the second aspect of the invention, the rotor 10 is formed of a magnetic material made of a manganese-aluminum-carbon alloy (Mn-Al-C). In this way, in this example, by using a manganese-aluminum-carbon based alloy as the magnet material,
It is possible to mirror-finish the deflection mirror 12, which requires a high reflectivity, and it is possible to form a rotor 10 that has excellent strength when used as a shaft, and in which the magnetic properties of the rotor magnet 11 do not deteriorate. In addition, other suitable magnet materials for the rotor 10 include Fe-Al-Ni-Co and Fe-
There are alloy magnets such as Cr-Co, Nd-Fe-B, and Pr-Fe-Co-B.

Further, as shown in FIG. 1, the deflection mirror 12 of this embodiment is formed as a pyramidal mirror according to the third aspect of the invention, and the deflection mirror 12 can be made smaller in size compared to a deflection mirror made of a polygon mirror. Achieved. Suitable deflection mirrors 12 that can be miniaturized include a V-shaped mirror and a tenon-shaped mirror as shown in FIGS. 2 and 3. In these deflection mirrors, two mirror surfaces 19 are formed, and the laser beam can be deflected and scanned at a rate of two per rotation.

FIG. 4 is a schematic configuration diagram showing an optical deflection device according to an embodiment of the invention as set forth in claim 4. In this embodiment, the same components as those in the above-mentioned example are designated by the same reference numerals, and detailed explanation thereof will be omitted. In the figure, a rotor magnet (first multipolar magnet) 1 formed as a rotor 10
A second multipolar magnet 2 having a number of poles greater than the number of poles of 1.
0 is formed on the rotor 10. A magnetic sensor 21 is arranged at a position facing the second multipolar magnet 20 and detects magnetic changes when the rotor 10 rotates. That is, at the arrangement position of the magnetic sensor 21, the magnetic force from the second multipolar magnet 20 changes sinusoidally due to rotation. By detecting this magnetic change, the second multipolar magnet 2
0 functions together with the magnetic sensor 21 as a frequency generator with rotation speed control.

In this way, in this embodiment, the rotation speed of the rotor 10 can be controlled by detecting the magnetic change of the rotating rotor 10 as a change in frequency, so that the deflection of the laser beam L can be controlled. Scanning can be achieved with high precision. FIG. 5 is a side sectional view showing an optical deflection device according to an embodiment of the invention. In this embodiment, the same components as those in the above-mentioned example are designated by the same reference numerals, and detailed explanation thereof will be omitted. In the figure, a single magnetic pole part 30 of an N pole or an S pole is formed in the circumferential direction of the rotor 10. An annular magnet 31 having the same magnetic pole as this single magnetic pole part 30
A pair of magnetic bearings 32 are formed by arranging them facing each other with a predetermined distance between them.

As described above, in this embodiment, by constructing the magnetic bearing 32 using a permanent magnet, electrical control can be made unnecessary. Therefore, a long-life magnetic bearing 32 that can withstand high rotations can be formed at low cost, and at the same time, reliability can be improved. FIG. 6 is a side sectional view showing an optical deflection device according to an embodiment of the invention. In this embodiment, the same components as those in the above-mentioned example are designated by the same reference numerals, and detailed explanation thereof will be omitted. In the figure, a deflection mirror 12 is formed at the tip of one end of a shaft 40 as a rotating shaft, and a rotor magnet 11 is magnetized on the outer periphery of the shaft 40. Furthermore, a single magnetic pole portion 41 is formed on the outer periphery of the shaft 40 so as to be continuous with the rotor magnet 11 . This single magnetic pole part 4
1 is a conical side wall surface 4 that is symmetrical with respect to the axis of the shaft 40;
2, and the magnetic pole of the conical side wall surface 42 is an N pole or an S pole.
It has a single magnetic pole. The single magnetic pole part 41 has an inclined surface 43 parallel to the conical side wall surface 42, and the inclined surface 43 is parallel to the conical side wall surface 42.
Annular magnets 44 having the same magnetic poles are placed facing each other and separated by a predetermined distance. A pair of magnetic bearings 45 is formed by the single magnetic pole portion 41 and the annular magnet 44 . Preferably, the opposing surfaces of the single magnetic pole portion 41 and the annular magnet 44 all have the same magnetic pole.

In this way, in this embodiment, since the single magnetic pole part 41 having the conical side wall surface 42 that becomes wider in the axial direction of the shaft 40 is provided, the magnetic bearing 45 constituted together with the annular magnet 44 allows the shaft to be Magnetically levitate the shaft 40 in both thrust (downward) and radial directions.
Long-life magnetic bearings that can withstand high rotations and restrain the movement of
5 can be formed at low cost. Moreover, by configuring the magnetic bearing 45 with a permanent magnet, electrical control can be made unnecessary, and reliability can also be improved.

Although the rotor magnet 11 and the single magnetic pole part 41 are continuous in this embodiment, they may be formed separately. Moreover, the magnetic bearing 45 according to this embodiment is attached to the shaft 4.
Two magnetic bearings 45 are provided, one each on the upper and lower sides of 0.
The conical side wall surfaces 42 may be aligned toward the center of the shaft or toward the ends of the shaft. In this case, the movement of the shaft 40 not only downward but also upward can be restrained, and the floating position of the shaft 40 in the thrust direction can be restrained.

By the way, in general, when a rotating body is attempted to rotate about the geometrical center axis A (see FIG. 7), vibrations such as whirling will occur if the rotating body is not perfectly balanced. Conventionally, this whirling was restrained by a bearing such as a ball bearing and rotated, but in this embodiment, the magnetic bearing 45 allows rotation around the main axis of inertia B. When rotated about the main axis of inertia B, vibrations due to whirling as described above do not occur. In other words, even if the shaft 40 (including the rotor magnet 11 and single magnetic pole part 41) is unbalanced when viewed from the geometric center axis A, there is always a balanced axis, that is, the principal axis of inertia B, and this If it is rotated around the principal axis of inertia B, it will not vibrate.

FIG. 8 is a characteristic diagram showing the measured deflection amount r in the optical deflection device using the magnetic bearing 45. In the figure, the solid line indicates the amount of deflection of the geometric center axis A, and the broken line indicates the amount of deflection of the center of gravity with respect to the principal axis of inertia B. Note that the intersection of the vertical axis and the broken line represents the eccentricity E0. In the low rotation region R, the restraining force of the shaft 40 due to the magnetic force, that is, the bearing rigidity is superior, so the shaft 40 rotates around the geometric center axis A, and the center of gravity is greatly swayed as shown by the broken line. . However, as the rotational speed becomes higher than the rotational speed ω0 at which the shaft 40 generates natural vibration, the shaft 40 is released from the bearing rigidity and begins to rotate about the main axis of inertia B. In the preferred rotational speed of this embodiment, that is, in a rotational range P of several tens of thousands of rpm, as shown by the broken line, stable rotation is possible by absorbing the amount of eccentricity of the center of gravity.

The invention of claim 4 can also be implemented in the above-mentioned embodiment, as shown in FIG. That is, by forming the second multipolar magnet 20 on either the single magnetic pole portion 41 or the rotor magnet 11 as shown in the figure, the rotational speed control as described above becomes possible. FIG. 10 is an enlarged view showing a joint portion of the annular magnet 44 in an optical deflection device according to an embodiment of the invention. In this embodiment, the same components as those in the above-mentioned example are designated by the same reference numerals, and detailed explanation thereof will be omitted. In the figure, the annular magnet 44 in the magnetic bearing 45 is connected to the motor housing 1 which becomes the main body of the device via a viscoelastic body 50.
3. The viscoelastic body 50 may be anything, such as an adhesive or double-sided tape, as long as it has both adhesive properties and elasticity.

According to this embodiment, vibrations caused by the reaction of the magnetic force that cannot be absorbed by the magnetic bearing 45 can be absorbed by the viscoelastic body 50, so that noise, the influence on images, etc. can be reduced. Note that the present invention is not limited to the above embodiment, and the magnetic bearing 3 described in FIG.
Naturally, the present invention also includes a configuration in which the annular magnet 31 and the motor housing 13 are coupled by the viscoelastic body 50 in No. 2.

FIG. 11 is a side sectional view showing a magnetic bearing in an optical deflection device according to an embodiment of the invention. In this embodiment, the same components as those in the above-mentioned example are designated by the same reference numerals, and detailed explanation thereof will be omitted. In the figure, two conical side wall surfaces 42 of the single magnetic pole portion 30 are formed toward the axial end direction of the shaft 40, and each conical side wall surface 4
An annular magnet 44 is disposed opposite to the magnet 2. Here, the same magnetic poles of the upper and lower conical side wall surfaces 42 and the inclined surface 43 of the annular magnet 44, which is the opposing surface thereof, are arranged to face each other and repel each other.

According to this embodiment, by sandwiching the single magnetic pole portion 41 between the annular magnets 44 from above and below in the axial direction, the movement of the rotor in the vertical thrust direction can be completely restrained. Therefore, even if the optical deflection device is turned upside down during transportation, the shaft 40 will not fall off, and there is no risk of damaging the deflection mirror. Note that the magnetic poles in the above embodiments can also be formed by magnetization. Further, the rotor magnet 11 has, for example, four poles,
It can be formed by appropriately selecting the number of magnetic poles such as two poles.

[0036]

As explained above, according to the optical deflection device according to the invention as set forth in claim 1, the rotor is formed in the shape of a shaft, and the deflection mirror is formed at the tip of one end of the rotor. By integrating the shaft, mirror, and rotor to form a shaft-shaped rotor, the number of parts is reduced from three to one, achieving improved precision and miniaturization through integration, reducing costs. can do.

Further, according to the optical deflection device according to the second aspect of the invention, since the rotor is formed of a magnet made of a manganese-aluminum-carbon alloy, mirror finishing of the deflection mirror, which requires a high reflectance, is possible. It is possible to form a rotor that has excellent strength when used as a shaft and does not cause deterioration in the magnetic properties of the rotor magnet. Further, according to the optical deflection device according to the third aspect of the invention, by using the deflection mirror as a pyramidal mirror, the deflection mirror can be made smaller in size compared to a deflection mirror made of a polygon mirror.

Further, according to the optical deflection device according to the invention as set forth in claim 4, the second multipolar magnet having a larger number of poles than the number of poles of the first multipolar magnet formed as a rotor is provided. By forming a magnetic sensor on the rotor and arranging a magnetic sensor that detects magnetic changes during rotation at a position facing the second multipolar magnet, magnetic changes in the rotating rotor are detected as changes in frequency. Since the rotation speed of the rotor can be controlled, deflection scanning of the laser beam can be realized with high precision.

According to the optical deflection device according to the fifth aspect of the invention, a single magnetic pole portion is provided in the circumferential direction of the rotor, and an annular magnet having the same magnetic pole as the single magnetic pole portion is separated by a predetermined interval. By arranging them facing each other to form a pair of magnetic bearings, it is possible to eliminate the need for electrical control, and it is possible to form a long-life magnetic bearing that can withstand high rotations at low cost, while also improving reliability. can also be improved.

According to the optical deflection device according to the invention as set forth in claim 6, the conical side wall surface is symmetrical with respect to the axis of the shaft, and the conical side wall surface has a single magnetic pole. By providing a pair of magnetic poles and arranging annular magnets having an inclined surface parallel to the conical side wall surface of the single magnetic pole section, and having the inclined surface having the same magnetic pole as the conical side wall surface, facing each other and separated by a predetermined distance, By forming the bearing, the shaft is magnetically levitated to restrain the movement of the shaft in both the thrust (downward) and radial directions, and a long-life magnetic bearing that can withstand high rotation can be formed at low cost.

Further, according to the optical deflection device according to the seventh aspect of the invention, since the annular magnet in the magnetic bearing is joined to the motor housing serving as the main body of the device via the viscoelastic body, the magnetic bearing cannot completely absorb the light. The vibration caused by the reaction of the magnetic force, which was not present, can be absorbed by the viscoelastic material, so
It is possible to reduce noise, the influence on images, etc. Further, according to the optical deflection device according to the invention described in claim 8, two conical side wall surfaces of the single magnetic pole portion are formed facing toward the axial end direction of the shaft,
By arranging the annular magnets to face each conical side wall surface, the single magnetic pole portion is sandwiched between the annular magnets from above and below in the axial direction, and the movement of the rotor in the vertical thrust direction can be completely restrained.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing an optical deflection device according to an embodiment of the invention according to any one of claims 1 to 3.

FIG. 2 is an external perspective view showing a second embodiment of a deflection mirror.

FIG. 3 is an external perspective view showing a third embodiment of a deflection mirror.

FIG. 4 is a schematic configuration diagram showing an optical deflection device according to an embodiment of the invention as set forth in claim 4.

FIG. 5 is a side sectional view showing an optical deflection device according to an embodiment of the invention as set forth in claim 5.

FIG. 6 is a side sectional view showing an optical deflection device according to an embodiment of the invention as set forth in claim 6.

FIG. 7 is a diagram showing the geometric center axis and principal axis of inertia in the shaft.

FIG. 8 is a characteristic diagram showing the amount of deflection measured in an optical deflection device using a magnetic bearing.

FIG. 9 is a schematic configuration diagram showing another embodiment of the invention according to claim 4.

FIG. 10 is an enlarged view showing a joint portion of annular magnets in an optical deflection device according to an embodiment of the invention;

FIG. 11 is a side sectional view showing a magnetic bearing in an optical deflection device according to an embodiment of the invention.

[Explanation of symbols]

10 Rotor 11 Rotor magnet (first multipolar magnet) 12
Deflection mirror 13 Motor housing 14 Electromagnetic coil 20 Second multipolar magnet 21 Magnetic sensor 30, 41 Single magnetic pole part 31, 44 Annular magnet 32, 45 Magnetic bearing 42 Conical side wall surface 43 Inclined surface

Claims (8)

[Claims] 1. An optical deflection device comprising a rotor having multiple N and S poles alternately formed in the circumferential direction, and an electromagnetic coil for driving the rotor, wherein the rotor is formed into a shaft shape. An optical deflection device characterized in that a deflection mirror is formed at the tip of one end of the rotor. 2. Claim 1, wherein the rotor is formed of a magnet made of a manganese-aluminum-carbon alloy.
The optical deflection device described. 3. The optical deflection device according to claim 1, wherein the deflection mirror is a pyramidal mirror. 4. A second multipolar magnet having a larger number of poles than the first multipolar magnet formed as a rotor is formed on the rotor, and the second multipolar magnet is 2. The optical deflection device according to claim 1, further comprising magnetic sensors arranged at opposing positions to detect magnetic changes during rotation. 5. A pair of magnetic bearings is formed by providing a single magnetic pole section in the circumferential direction of the rotor, and arranging annular magnets having the same magnetic pole as the single magnetic pole section and facing each other with a predetermined separation distance. The optical deflection device according to claim 1. 6. An optical deflection device comprising a rotor driven by an electromagnetic coil, a shaft serving as a rotation axis of the rotor, and a deflection mirror that rotates together with the shaft to reflect and deflect incident light, A single magnetic pole portion having a conical side wall surface symmetrical with respect to the axis of the shaft and having a single magnetic pole on the conical side wall surface, and an inclined surface parallel to the conical side wall surface of the single magnetic pole portion. What is claimed is: 1. An optical deflection device characterized in that a pair of magnetic bearings is formed by arranging annular magnets having an annular magnet whose inclined surface has the same magnetic pole as the conical side wall surface and facing each other with a predetermined distance from each other. 7. The optical deflection device according to claim 5, wherein the annular magnet in the magnetic bearing is joined to a motor housing serving as the main body of the device via a viscoelastic body. 8. The single magnetic pole part has two conical side wall surfaces facing toward the axial end of the shaft, and an annular magnet is disposed to face each conical side wall surface. Light deflection device.