JPS59222827A - Scanning and exposing device - Google Patents

Abstract

PURPOSE:To prevent a copied image from the deterioration in quality by arranging a slit member between the 1st and 2nd mirrors to prevent a photosensitive body from being irradiated by unnecessary light at the time of scanning. CONSTITUTION:The 1st and 2nd mirrors 1, 2 constituting a scanning optical system are fixed on a supporting stand 10 so as to be crossed at right angles and the supporting stand 10 is moved in the arrow direction at a half speed of the photosensitive body 4 to scan the photosensitive body 4. A slit member 11 having a slit-like opening is fixed on the supporting stand 10. When the mirrors 1, 2 and the slit member 11 are unitedly moved, effective light flux projected to a slit exposure part of the photosensitive body 4 always passes the opening 12 of the slit member 11 without partial interruption, but unnecessary light (harmful light) other than the effective picture light flux is interruped by the slit member 11.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a scanning exposure apparatus such as an electrophotographic copying machine that includes a scanning mirror on the image field side of a lens and performs slit exposure on a photoreceptor by moving the scanning mirror.

Conventionally, this type of exposure optical system is as shown in Fig. 1.
A first mirror 1 and a second mirror 2 are provided on the image field side of the lens L, and the first and second mirrors 1.2 are moved in the direction of the arrow from the dashed line position to the solid line position at a - speed of the photoreceptor 4, A device is known in which an image on a film 6 illuminated by a lamp 5 is slit-exposed onto a photoreceptor 4. When changing the copying magnification, use a zoom lens as the lens L, or change the optical path length (2) by changing the position of the scanning optical system, and adjust the scanning optical system to the negative speed of the photoreceptor 4, that is, regardless of the change in magnification. It is sufficient to always move at a constant speed.

According to this exposure optical system, when the mirror 1.2 is moved, the structural part of the document that is imaged on the slit exposure section indicated by the symbol S in the figure moves on the mirror 1.2, so that the scanning mirror is moved. Due to the large size, unnecessary light enters the scanning mirror due to reflection inside the apparatus, and this unnecessary light is irradiated onto the photoreceptor, resulting in a problem that the quality of the copied image deteriorates.

The present invention aims to solve the above problem, and provides a scanning exposure apparatus in which a slit member is provided between two scanning mirrors to prevent unnecessary light from being irradiated onto a photoreceptor.

The present invention will be explained below with reference to the drawings.

FIG. 2 shows an electrophotographic copying machine to which the present invention is applied, and hereinafter, parts having the same structure as that shown in FIG. 1 are designated by the same reference numerals. First and second mirrors 1 constituting the scanning optical system
The fist 2 is fixed to a support base 10 in a perpendicular and intersecting relationship, and the support base 10 is coupled to a drive source (motor) and moves in the direction of the mirror lΦ. The mirror 2 is normally placed at the dashed line position, and by moving at a constant speed from the dashed line position to the solid line position, slit exposure is performed on the photoreceptor 4, which rotates at a constant speed, thereby exposing the entire surface of the image to be copied onto the photoreceptor. exposed to light. After exposure, mirrors 1 and 2 return to the positions shown by the broken lines.

Reference numeral 11 denotes a slit member fixed to the support base 10, which has a slit-shaped opening 12 as shown in FIG. 3, and the above-mentioned unnecessary light rays are blocked by this slit member.

During copying, while the first and second mirrors 2 move from the broken line position to the solid line position, the image light flux of the original (
The optical path through which the light beam (hereinafter referred to as effective light flux) passes changes from the optical path a shown in the figure to the optical path a. The arrangement position of the slit member 11 can be determined, for example, by temporarily fixing the first mirror 1 and the second mirror 2,
Considering that the effective light flux moves on the first and second mirrors, there is a part where the effective light flux commonly passes between the first and second mirrors, and in this part, the optical paths that change sequentially intersect. It is placed at the intersection of these optical paths. Therefore, the slit member is arranged in a portion where the effective light beams commonly pass. By arranging the slit member at such a position, when the mirrors 1 and 2 and the slit member 11 move integrally, the effective light beam projected onto the slit exposure part of the photoreceptor is not partially blocked and is always connected to the slit member. 11, but unnecessary light (harmful light) other than the effective image light beam is blocked by the slit member.

The distance between the film 6 and the first mirror 1 and the distance between the photoreceptor 4 and the second mirror 1
Depending on the distance between the mirrors 2, the portion through which the effective light flux commonly passes changes. When the two distances mentioned above are equal, the first
+1 Place a slit member in the middle of the second mirror. In any case, the slint member moves integrally with the first and second mirrors while the first and second mirrors are moving, and only the light beam of the area to be projected on the document is projected onto the photoreceptor.

As the photoreceptor, an electrophotographic photoreceptor, a photoelectric conversion element, and other known photosensitive materials can be used.

FIG. 4 shows an embodiment in which a COD image sensor 20 is used as a photoreceptor, and the sensor 20 is fixed at an imaging position and consists of a one-dimensional line sensor that linearly scans an image in the main scanning direction. The image is sub-scanned by the movement of the first and second mirrors lΦ2.

As a result, the entire image is photoelectrically converted.

5 and 6 show other embodiments of the slit member, and the slit member 111 shown in FIG. l, Nru.

The slit member 211 shown in FIG. Consists of materials.

As described above, according to the present invention, by moving the first and second mirrors, harmful light rays other than image light are incident on the photoreceptor when the original image is exposed to the slit of the photoreceptor. You can read ahead or copy the original by 1 minute without fear.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a conventional copying machine, Fig. 2 is a block diagram of a copying machine showing one embodiment of the present invention, Fig. 3 is a front view of a slit member, and Fig. 4 is another embodiment. 5 and 3 are front views of other embodiments of the slit member; FIG. 1.2---Mirror 11---Slit member

Claims (3)

[Claims] (1) A lens for projecting an image of an original onto a photoreceptor; and a first lens, which is disposed between the lens and the photoreceptor, intersects with each other, and moves in predetermined directions. Second
A scanning exposure apparatus comprising: a mirror; and a slit member disposed between the first mirror and the second mirror. (2) The scanning exposure apparatus according to claim 1, wherein the first and second mirrors are positioned to intersect at right angles and move integrally. (3) The scanning exposure apparatus according to claim 2, wherein the slit member moves integrally with the first and second mirrors.