JPH0284611A - Optical deflector - Google Patents

Abstract

PURPOSE:To facilitate high-speed scanning of a scanner by constituting plural pentago nal prism monogons the mirrors of which themselves have the function to correct a surface inclination in such a manner that the monogons can be freely rotated. CONSTITUTION:The plural pentagonal prism monogons 6, 8 are disposed to a rotary plate 4f around a central revolving shaft 2 of a motor M, by which the monogons 6, 8 are rotated in the same direction as well when the revolving shaft 2 and the rotary plate 4 operate according to the revolution of the motor M. The monogon 6 has mirror surfaces 10, 12 which form reflecting surfaces and surfaces 14, 16 which do not form the reflecting surfaces, etc., Laser light 20 or the like past a collimator lens 18 transmits through the surface 14 and is thereafter reflected successively by the reflecting surfaces 12, 10. The reflected light rays are emitted as collimated beams 22 of light from the monogon 6. These beams form an image on the imaging plane 26 by an ftheta lens 24. Incident light 20 is reflected by the reflecting surfaces 12, 10 to form the collimated beams 22a of light which are emitted from the monogon 6 and are imaged on the imaging surface 26 by the ftheta lens 24 even if the monogon 6 generates some surface inclination during the revolution of the motor M. The monogon 6 itself makes the surface inclination correction action in such a manner. The high-speed scanning is facilitated in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The invention of this application relates to an optical deflection device. More specifically, the present invention relates to an optical deflection device incorporating a scanner capable of correcting surface tilt.

(Prior Art and Problems to be Solved by the Invention) Conventionally used optical deflection devices employ a polygon mirror as a scanner, and incident light such as laser light is reflected by a plurality of equiangular reflection surfaces on the outer peripheral surface. By irradiating the photosensitive drum with reflected light that is incident on the reflective surface and reflected at the same time according to the rotation of the central axis of the mirror equipped with the mirror, information such as laser light is created as a latent image on the photosensitive drum through an optical lens system, etc. It was formed as

However, due to the mechanical precision of the rotation axis of the polygon mirror, the surface of the polygon mirror tilts, and the multiple reflected lights on the reflective surface of the polygon mirror do not form parallel lights, and as a result, the optical lens system Even if these non-parallel beams are corrected, there are still problems such as the inability to form an image on the photosensitive drum at a predetermined position.

Therefore, by improving the accuracy of the parts related to the rotation axis of Polygon Mira, and at the same time adopting an electrical feedback method,
A method of correcting the surface tilt was also attempted, but it was difficult to obtain the desired results.

(Means for Solving the Problems) Therefore, the present invention provides an optical deflection device having a scanner in which a plurality of pentaprism monogons are rotatably configured, and the mirror itself has a function of correcting the surface tilt. More specifically, when the motor is rotated, a plurality of pentaprism monogons are used to make light incident parallel to the rotational axis of the motor be emitted as parallel light by two opposing reflecting surfaces in a direction perpendicular to the incident light. This optical deflection device includes a scanner arranged symmetrically on a plate with the rotation axis as the center.

(Function) The scanner of the optical deflection device of the present invention itself performs a surface tilt correction function, and a plurality of ventabrism monogons are arranged symmetrically and in a well-balanced configuration around the motor rotation axis. Therefore, desired scanning can be obtained every rotation of the motor. Therefore, the scanner performs high-speed scanning.

(Embodiment) An embodiment of the optical deflection device according to the present invention will be described below with reference to the accompanying drawings.

A plurality of ventabrism monogons 6°8 (in this embodiment, 2
Although one is shown in the figure, two or more can be provided as desired.

Therefore, when the rotating shaft 2 and rotating plate 4 operate in accordance with the rotation of the motor M, the pentaprism monogons 6 and 8 disposed on the rotating plate also rotate in the same direction. The Ventabrism monogon 6 has a mirror surface 10.12 that forms a reflective surface, a surface 14.16 that does not form a reflective surface, etc., and the laser beam 20 that has passed through the collimator lens 18 is parallel to the rotation axis 2. After passing through the surface 14 that does not form a reflective surface, the reflective surface 12.10
are sequentially reflected and emitted from the Ventabrism monogon 6 so as to be orthogonal to the incident light as parallel lights 22, respectively, and
Next f.

The lens 24 forms an image on its imaging plane 26 .

Therefore, even if the pentaprism monogon 6 falls down slightly during rotation of the motor M, the incident light 20 is reflected by the reflecting surfaces 12 and 10 and becomes parallel light 22a, respectively, and the pentaprism monogon 6 (See Figure 2 for better output)
, then an image is formed on the imaging plane 26 by the fθ lens 24. In this manner, the vantaprism monogon 6 itself of the present invention performs a surface tilt correction function.

In the present invention, the above-mentioned surface tilt correction function is performed by itself.
A plurality of pentaprism monogons are arranged symmetrically on the motor rotating plate 4, and it is possible to scan as many pentaprism monogons as the number of arranged pentaprism monogons per rotation of the motor M, and it is compatible with high speeds. There are also advantages such as the ability to obtain a desired number of scans, and furthermore, by attaching a plurality of pentaprism monogons to one motor in a well-balanced and symmetrical manner, it is useful for improving the performance of the optical deflection device.

(Effects) Since the scanner of the optical deflection device of the present invention itself performs a surface tilt correction function, compared to the conventional example which improves the accuracy of rotating shaft-related members and adopts an electrical feedback method. This makes it easy to correct the surface tilt, and by mounting multiple scanners symmetrically on the motor rotation plate around the motor rotation axis, it is easy to perform the desired scanning every time the motor rotates. Therefore, it is possible to meet the needs of the industry as a high-speed deflection device.

[Brief explanation of the drawing]

FIG. 1 is a side view of an optical deflection device incorporating a scanner according to the present invention, and FIG. 2 is a route diagram showing a surface tilt correction function of the scanner itself. 2... Rotation axis, 4... Rotating plate, 6.8... Ventabrism monogon, 10.12... Reflection surface of Ventabrism monogon, 18... Collimator lens, 20.
...Incoming laser beam, 22 parallel beams. 24...fθ lens.

Claims (1)

[Claims] 1. Light incident in the direction of the rotation axis of the motor in parallel with the rotation axis,
A plurality of pentaprism monogons, which are reflected by opposing reflecting surfaces and emitted as parallel light in a direction perpendicular to the incident light, are arranged symmetrically on the motor rotary plate with the rotation axis as the center, An optical deflection device that includes a scanner that allows scanning to be performed a desired number of times per rotation. 2. The light from the light source passes through the collimator lens and enters the pentaprism monogon parallel to the rotation axis direction, and the light emitted from the monogon in a direction perpendicular to the incident light is expressed as fθ
2. The optical deflection device according to claim 1, wherein the image is formed on an imaging surface of an optical drum via a lens.