JPS61118720A - Scanner - Google Patents

Abstract

PURPOSE:To control the deflection of a motor shaft and to rotate it at a constant position with high precision by supporting an end of the motor shaft on a pivot and composing a dynamic fluid bearing of a thrust disk and working fluid. CONSTITUTION:The pivot 5 in the center of a frame 1 is fitted loosely in the recessed part 7 in the center of the reverse surface of the motor shaft 6 to support the shaft 6 rotatably, and the working fluid 12 charged in an airtight chamber 11 surrounding the thrust disk 8 is stirred in grooves which are formed in both surfaces of the disk 8 and curved readily to constitute the dynamic fluid bearing. When the motor shaft 6 rotates, its radial deflection is controlled by the pivot 5 and the swing rotation is controlled with the dynamic pressure of the working fluid 12, so the motor shaft 6 is rotated at the constant position with high precision.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a scanner used for reading, recording, etc. information.

2. Description of the Related Art Recently, there has been a demand for high precision in polygon mirror scanners, hologram scanners, and the like. For example, the processing accuracy of polygon mirrors has improved, and the division accuracy and surface tilt accuracy of each face is less than 3 seconds.
The surface accuracy of each surface is λ/8 or less (λ=0.633 μm). As shown in FIG. 6, the conventional polygon mirror scanner has a scanning motor shaft 1020 rotatably supported by ball bearings 103 and 104 on both sides of a housing 101. A stator 106 is attached to the inside of the housing 101,
A rotor magnet 106 is attached to the motor shaft 102 inside the stator 105, and the rotor magnet 106 and the stator 105 constitute a DC brushless motor, and the motor shaft 101 is rotated. A polygon mirror 107 is mounted on the motor shaft 101, and this polygon mirror 107 is connected to the window 1 formed in the housing 101.
I am facing 0B.

Problems to be Solved by the Invention However, in the configuration in which the motor shaft 101 is supported by the ball bearings 103 and 104, the polygon mirror 10
It is impossible to rotate while maintaining the accuracy of 7.

Therefore, in order to meet the demand for improving the accuracy of the polygon mirror 107 with the above configuration, it is necessary to use an optical polarizer or the like. In this case, the cost will increase.

SUMMARY OF THE INVENTION Therefore, the present invention aims to provide a scanner that is inexpensive and can achieve high accuracy.

Means for solving the problems The technical means of the present invention for solving the above problems are as follows:
a frame; a pivot attached to the frame;
A scanning motor shaft whose one end is rotatably supported by the pivot, a thrust disk attached to the motor shaft, a sealed chamber formed outside the thrust disk within the frame, and the sealed chamber. a working fluid sealed in the thrust disk; It is equipped with an operating section that operates the fluid.

Operation According to the present invention, when the scanning motor shaft is rotated by the above-described structure, the swing of the motor shaft in the radial direction is restricted by the pivot.

Furthermore, when the motor shaft and the thrust disk rotate, the operating section rotates the working fluid, and this working fluid generates load capacities on both sides of the thrust disk, and these load capacities restrict the whirling of the motor shaft. Ru. Therefore, the motor shaft can be rotated in a fixed position with high precision.

EXAMPLE Hereinafter, an example in which the present invention is implemented in a polyhedral scanner will be described in detail with reference to the drawings. Sea urchin frame 1 as shown in Figure 1
is composed of a base 2, a thrust disk pressing member 3 attached to the pace 2, and a cylindrical portion 4 integrally provided with the thrust disk pressing member 3. A scanning motor shaft 6 is inserted into the frame 1 to which the pivot 2 is attached, and a conical recess 7 formed in the center of one end of the motor shaft 6 is inserted into the frame 1 to which the pivot 6 is attached. 60 is rotatably supported on the conical part.

A thrust disk 8 is attached to the end of the motor shaft 6 on the recess side.
is installed. A disk-shaped magnet 9 is attached to the motor shirt 6 located inside the thrust disk-holding member 3, and the space between the disk-shaped magnet 9 and the thrust disk-holding member 3 is sealed by a magnetic fluid 10. , a sealed chamber 11 is formed outside the thrust disk 8.

A working fluid 12 is sealed in this sealed chamber 11 . At least one of the two sides of the thrust disk 8 and the opposing surface in the closed chamber 11, and the other side of the thrust disk 8 and the closed chamber 1
Working fluid 1 on at least one of the opposing surfaces in 1, respectively.
An operating section for operating the device 2 is provided. In this embodiment, as an example, as shown in FIGS. 3 and 4, grooves 13.
4 is formed. The six grooves 13 and 14 are curved in the same direction, that is, formed in a spiral shape, so that the distance from the axis 0 becomes gradually shorter from the outer end to the inner end. These thrust disks8. The closed chamber 111 working flow 2 and 113 and 14 constitute a dynamic pressure type fluid bearing.

A stator 16 is attached to the inside of the cylindrical portion 4, and a rotor magnet 16 is attached to the motor shaft 6 inside the stator 15. These rotor magnets 16 and the stator 16 constitute a DC brushless motor, and the motor shaft 6 is rotated. A polygon mirror 17 is attached to the protrusion of the motor shaft 6.

Next, the operation of the above embodiment will be explained. As described above, as the motor shaft 6 rotates in the direction of the arrow C shown in FIGS. 2 to 4, the polygon mirror 17 is rotated to perform scanning. At this time, the swing of the motor shaft 6 in the radial direction is restricted by the pivot 5. Furthermore, when the motor shaft e and the thrust disk 8 rotate in the direction of the arrow C, the thrust disk 8 is provided with a plurality of spiral grooves 13 and 14 on its outer circumference as described above, so these grooves 1314 The working fluid 12 is rotated, and the working fluid 12 produces load capacities FA and FB on both sides of the thrust disk 8, respectively, and the motor shaft 6 has these load capacities FA and FB.
Swinging is regulated by the force of.

Therefore, the motor shaft 6 can be rotated with high accuracy in a fixed position, and thereby the rotational accuracy of the polygon mirror 17 can be guaranteed.

Incidentally, the operating portion may use a real strip instead of the grooves 13, 14.

Effects of the Invention As is clear from the above explanation, according to the present invention, one end of a scanning motor shaft is rotatably supported by a pivot attached to a frame, and a sealed chamber is provided outside a thrust disk attached to the motor shaft. A fluid bearing is formed by sealing a working fluid in the sealed chamber, and providing a working fluid operating portion in at least one of the thrust disk and the sealed chamber.

Therefore, the pivot can prevent the motor shaft from swinging in the radial direction, and the fluid bearing can prevent the motor shaft from swinging around by applying a load capacity force to both sides of the restrust disk. High precision rotation can be achieved. Furthermore, since a conventional optical polarizer is not required, costs can be reduced.

[Brief explanation of the drawing]

1 to 4 show an embodiment of the scanner of the present invention, in which FIG. 1 is a sectional view, FIG. 2 is a sectional view of the fluid bearing section, and FIG.
The figure is a partial plan view of the thrust disk, FIG. 4 is a partial bottom view of the thrust disk, and FIG. 6 is a cross-sectional view of a conventional polygonal mirror scanner. 1...Frame, 2...Base, 3.
...Thrust disk holding member, 5...Pivot, 6...Motor shaft, 8...
Thrust disc, 9...Disc-shaped magnet, 11
... Sealed chamber, 12 ... Working fluid, 13
．． 14... Groove (operating part), 15... Stator, 16... Rotor magnet, 17...
...Polygon mirror. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3

Claims (1)

[Claims] a frame; a pivot attached to the frame;
A scanning motor shaft whose one end is rotatably supported by the pivot, a thrust disk attached to the motor shaft, a sealed chamber formed outside the thrust disk within the frame, and the sealed chamber. a working fluid sealed in the thrust disk; A scanner characterized in that it includes an operating section that operates a fluid.