JPS5831301A - Polygon mirror - Google Patents

Abstract

PURPOSE:To form an image and to scan a reflected beam light on a desired locus line without a condensing optical system, by arranging a reflective mirror, which has such curvature that the reflected beam light is formed the image in a prescribed position, on each circumferential face of a regularly polygonal column. CONSTITUTION:In a polygon mirror 2, a reflective mirror 2, having a constant curvature is arranged on each circumferential face of the shape like a regularly polygonal column. A concave mirror, a convex mirror, an aspherical mirror, or a toroidal face mirror is used as the reflective mirror 2b. This reflective mirror 2b has such curvature that a beam light B from a beam light source 1 is reflected and is form an image on a face 4 to be scanned which is arranged at a prescribed interbal. Thus, the reflected beam light is formed the image on a certain desired locus line without a complicated condensing optical system.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polygon mirror used in a scanner device, etc., which scans and forms a reflected beam on a certain desired trajectory line without using an intervening condensing optical system. The purpose is to make it possible.

FIG. 1 shows a conventional example of the most typical configuration of a scanner device, and reference numeral 1 denotes a beam light source.

Reference numeral 2 represents a polygon mirror, 3 represents a condensing optical system, and 4 represents a surface to be scanned.The beam light B emitted from the beam light source 1 is reflected by the polygon mirror 2 and its optical path is bent.
, and is imaged on the scanned surface 4.

That is, the beam B incident on the polygon mirror 2 is.

It is reflected by one predetermined reflecting mirror 2a of the polygon mirror 2.

The light passes through the condensing optical system 3 and is imaged on the scanned surface 4.

Scanning is performed in the direction of arrow A in response to changes in the reflection angle of the reflecting mirror 2a as the polygon mirror 2 rotates.

In such an apparatus, since the reflecting mirror 2a of the conventional polygon mirror 2 is a mere plane mirror, the condensing optical system 3 for focusing the reflected beam light B from the two reflecting mirrors 2a on the scanned surface 4 is Since the angle of incidence of the beam B changes as the polygon mirror 2 rotates, it is difficult to assemble a large number of lenses, requiring an expensive, complicated and precise configuration, and requiring careful attention to the positioning of the lenses. I had to pay attention.

The present invention aims to omit the condensing optical system, which has extremely difficult problems in the above-mentioned apparatus, and to scan the reflected beam directly onto the surface to be scanned by using the polygon mirror itself. This is groundbreaking.

□ To explain one embodiment of the present invention with reference to the drawings, in FIG. Reflector 2 having a constant curvature on each circumferential surface of the column (column)
This is a configuration in which b is arranged.

In the illustrated example, the reflecting mirror 2b is a concave mirror, but it may also be a convex mirror, an aspherical mirror, or a tridal mirror.
The shape of the curvature is most preferably shaped depending on the purpose of use, but it is a curvature that allows the beam light BTh from the beam light source 1 to be reflected and imaged on the scanned surface 4 arranged at a predetermined interval. It is.

Therefore, in the polygon mirror according to the present invention, the beam light source 1
The light beam B from the polygon mirror 2 is incident on the reflecting mirror 2a of the polygon mirror 2, and then can be directly imaged on the surface to be scanned 4 for scanning. There is no need for a complicated configuration in which the system condenses light and forms an image on the scanned surface 4.

Therefore, in scanner devices, etc., the setting is easy and workability is good, and there is no need to use an expensive and complicated focusing optical system. It is.

[Brief explanation of the drawing]

FIG. 1 is a layout diagram of a conventional reflecting device using a polygon mirror, and FIG. 2 is a layout diagram of a reflecting device using a polygon mirror according to the present invention. Explanation of symbols 1...beam light source, 2...polygon me 2a...
・Reflector, 3... Condensing optical system, 4... Scanned surface, B
...beam light. Applicant (inventor) Motosuke Kiyohara

Claims (1)

[Claims] A polygon mirror that is made up of a regular polygonal prism, with a reflecting mirror having a certain curvature arranged on each cylindrical surface to form an image of the reflected beam at a predetermined position.