JPH0486722A - Laser scanner with single face mirror - Google Patents

Abstract

PURPOSE:To eliminate the need for a correction lens, etc., for making optical correction and to reduce costs by forming the reflecting surface for deflecting a laser beam as one surface. CONSTITUTION:The number of the reflecting surface of the reflecting mirror 1 is one surface. The laser beam generated from a semiconductor laser 3 is deflected via a collimation lens 4 to the same height by the reflecting mirror 1 of the single reflecting surface to be rotated by a motor 2. The deflected laser beam is scanned on a photosensitive drum 8 via an Ftheta lens 5 and a turnback mirror 7. An electrostatic latent image is drawn on the photosensitive drum 8 by this laser beam. The laser beam is scanned at the same height in such a manner and, therefore, the need for the correction lens is eliminated and the cost is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Purpose of the Invention (Industrial Application Field) The present invention relates to an m-plane mirror laser scanner used, for example, in a laser beam printer.

(Prior Art) A conventional laser scanner used in a laser beam printer or the like rotates a polygon mirror 12 having a plurality of reflective surfaces 11 as shown in FIG. 2 to emit laser beam light. There are things that are designed to deflect it. In this type of laser scanner, when the polyhedral mirror 12 rotates once, the number of surfaces of the reflective surface 11 is scanned by the laser beam light.

(Problems to be Solved by the Invention) In conventional laser scanners, each time a polyhedral mirror having a plurality of reflective surfaces rotates, the laser beam light is scanned as many times as the number of reflective surfaces. This tends to cause differences in the height of the beam scanned on each side of the surface. In order to make this height the same, it is generally necessary to perform optical correction using a correction lens such as a cylindrical lens or a toric lens, and such correction lenses are expensive, resulting in high costs. In addition, in order to avoid the use of such a correction lens, it is necessary to finish the surface inclination of the multiple reflective surfaces of the polygon mirror with extremely high precision, and even if such measures are taken, there is the problem of high processing costs. there were.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a single mirror laser scanner that does not require a correction lens or the like for optical correction and can reduce costs.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a laser scanner that deflects a laser beam using a rotating reflecting mirror, the reflecting surface of the reflecting mirror being The gist is what will be on the first page.

(Function) The laser beam is deflected by a rotating mirror with a single reflecting surface and scanned at the same height, eliminating the need for a correction lens.

When applied to a laser beam printer, the number of reflective surfaces in the reflective mirror is determined by the printer speed, resolution, and the number of rotations of the motor that rotates the reflective mirror. can be adequately addressed by a single-mirror laser scanner that has a reflector with a single reflective surface.

(Example) Hereinafter, an embodiment of the present invention will be described based on FIG.

This embodiment is applied to a laser beam printer.

In the figure, reference numeral 1 denotes a reflecting mirror, and the number of reflecting surfaces thereof is one. Reference numeral 2 denotes a motor for rotating the reflecting mirror 1, and a motor with a normal rotation speed level is used. 3 is a semiconductor laser, 4 is a collimator lens, 5 is F
A θ lens is used, and a surface toric one is used. 6 is a beam detector, 7 is a folding mirror, and 8 is a photosensitive drum.

The laser beam generated by the semiconductor laser 3 is then deflected to the same height by a single reflecting mirror 1 rotated by a motor 2 via a collimation lens 4. The deflected laser beam is scanned onto the photoreceptor drum 8 via the Fθ lens 5 and the folding mirror 7, and an electrostatic latent image is drawn on the photoreceptor drum 8 by the laser beam. The electrostatic latent image is then developed with toner and printed onto paper.

The number of reflective surfaces in the reflective mirror is determined by the printer speed, resolution, and rotation speed of the motor 2 of the laser beam printer, or is determined by the printer speed, resolution, and rotation speed of the motor 2 of the laser beam printer. A reflector 1 with a single reflective surface is sufficient for this purpose. Table 1 shows, as a reference example, printer speeds and motor rotational speeds that can be supported by the single reflecting mirror 1.

Table 1 It comes.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a width mirror laser scanner according to the present invention, and FIG. 2 is a perspective view showing a conventional polyhedral mirror. A reflector with one reflective surface, two motors, and three semiconductor lasers. Generations! Sleep! Hidekazu Miyoshi Chokashi The above motor rotation speed can be achieved with the motor 2 having a normal rotation speed level. [Effect of the invention]

Claims (1)

[Scope of Claim] A single mirror laser scanner that deflects a laser beam using a rotating reflecting mirror, characterized in that the reflecting mirror has one reflective surface.