JPH03181968A - Copying machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Al Industrial Field of Application) The present invention relates to a variable-magnification copying machine in which an optical device scans an original on a fixed original table to make a copy.

(b) Prior Art Generally, when forming an image using a copying machine, an optical device scans an original on a fixed document table, a photoreceptor is exposed to light, a latent image is formed on the photoreceptor, and a developing device is used to form a latent image on the photoreceptor. toner adheres to the surface. The toner image is transferred to the fed paper,
The sheet of paper on which image formation has been completed after being fixed by the fixing device is discharged.

Conventionally, the optical device used to change magnification in such a copying machine was
A device that uses a typical zoom lens to change the magnification without changing the distance between the document surface and the image forming surface; ■ A device that uses a fixed focus lens to change the distance between the document surface and the image forming surface; There is a device that changes the position of the focusing lens and the mirror. Furthermore, in the device described in (A), the reflected light that has passed through the lens is changed in the 180' direction by two mirrors placed at 90', and the reflected light with its direction changed is sent to the photoreceptor by another mirror. (b) A mirror is placed between the lens and the photoreceptor, and the position and angle of this mirror are changed by moving the two mirrors parallel to the optical axis. There are some methods that change the distance between the document surface and the image forming surface by changing .

(C) Problems to be Solved by the Invention However, the variable magnification device described above has the following problems in terms of cost and mechanism.

In the device (2), the mirror system is fixed, so the configuration is simple, but the zoom lens is expensive, and the mechanism for changing the relative positions of the lenses that make up the zoom lens is complicated and large. It ends up.

In the device of ■, (a) two mirrors placed at 90 degrees are required, which increases the number of mirrors and the number of parts involved; (b) the number of mirrors does not increase, but the position of the 5th mirror is changed. At the same time, since it is necessary to change the angle, the mechanism becomes complicated.

Therefore, an object of the present invention is to provide a copying machine capable of variable magnification with a simple mechanism at a low cost overall by using a mechanically simple optical device with a minimum number of parts such as mirrors. be.

FD1 Means for Solving the Problems In the present invention, a photoreceptor is provided in the center of the copying machine body, a light source lamp and a first mirror that run under the fixed document table are provided at the upper part of the copy machine body, and the fixed document table is provided with a fixed focus lens disposed below; a second mirror and a third mirror that guide the document reflected light from the first mirror to the fixed focus lens; In the copying machine, the copying machine includes a device including a fourth mirror that guides the light to the photoconductor, the fixed focus lens and the fourth mirror being arranged along the optical axis of the document reflected light from the third mirror. a belt-shaped photoconductor, which is movable in parallel with the fourth mirror, and an area of the photoconductor that is irradiated with the document reflected light from the movement range of the fourth mirror forms a plane perpendicular to the document reflected light; It is characterized by the following.

(IJ effect) In the copying machine according to the present invention, the photoreceptor in the center of the copying machine body is formed into a belt, and its exposure area is a plane perpendicular to the optical axis of the document reflected light from the optical device. The fixed focus lens of the device is movable parallel to the optical axis of the reflected light from the document, so that the magnification can be varied, and a fourth mirror that guides the reflected light from the document that has passed through the fixed focus lens to the photoreceptor is similarly arranged along the optical axis. It allows for parallel movement and adjusts the distance between the document surface and the image forming surface.At this time, since the angle of the fourth mirror is not changed, the irradiation position on the photoreceptor will be shifted, but the irradiation position will be shifted from the movement range of the fourth mirror. Since the area hit by the light is a plane perpendicular to the reflected light from the original, normal exposure can be performed even if the exposure position on the photoreceptor moves due to zooming.

(f) Embodiment FIG. 1 is a schematic diagram of the optical device and the vicinity of the photoreceptor of a copying machine according to the present invention.

A belt-shaped photoreceptor 2 is provided in the center of the copying machine main body 1, and a charger 3, a blank lamp 4, a developing device 5, and other process devices (not shown) are arranged around it. There is. A copy lamp 80, a first mirror 81, a second mirror 82, and a third mirror 8 are provided at the top of the main body l.
4, an optical device 8 including a fixed focus lens 85, a fourth mirror 86, etc. is provided. The fixed focus lens 85 and the fourth mirror 86 are movable in parallel to the optical axis of the reflected light from the document. A fixed document table 6 is disposed above the optical device 8 . The pectoid photoreceptor 2 has rollers 21, 2
2 and 23, and M between rollers 21 and 22.
Thi is perpendicular to the optical axis of the original reflected light from the fourth mirror 86, and is a plane that includes the entire area on which the original reflected light irradiated from the moving range of the fourth mirror 86 hits. There is.

The copying process in this copying machine will be explained.

When a print key (not shown) is pressed, the optical device 8 scans the original and exposes the belt-shaped photoreceptor 2 to slitting light. At this time, when the magnification is manually adjusted using keys on the operation panel (not shown), the formula 1/a + 1/b = 1/f, b/a =
M (a is the distance between the lens document surfaces, b is the distance between the lens photosensitive surfaces, f is the focal length, and M is the magnification.

), the optical path length and the position of the fixed focus lens 85 are moved by a known method. Fixed focus lens 85
The change in the distance between the document surface and the image forming surface due to the movement of the position of
Move and adjust the mirror 86. This shifts the exposure position on the surface of the belt-shaped photoreceptor 2, but since the exposure position of the belt-shaped photoreceptor 2 is a plane perpendicular to the optical axis of the original reflected light from the 45th roller 86, it is difficult to determine which position. The photoreceptor surface can be subjected to slit exposure even when the photoreceptor is at the exposure position. When the exposure is completed, a latent image is formed on the surface of the belt-shaped photoreceptor, and a 1-ner is attached to it in the developing device 5. This toner image is transferred onto the fed paper, fixed in the fixing section, and then ejected.

(g1 Effects of the invention As described above, according to this invention, in an optical device,
A fixed focus lens with a simple and inexpensive mechanism is used, which can be moved parallel to the optical axis, and the distance between the document surface and the imaging plane, which changes as the fixed focus lens moves, is adjusted so that the fourth mirror is moved parallel to the optical axis. Move and adjust. At this time, the mechanism was simplified and the fourth
Since the angle of the mirror is not changed, the position of the document reflected light on the photoconductor is shifted, but by making the photoconductor into a heald shape, the range of the shift of the irradiation position, that is, the exposure area, is adjusted to the original position from the optical device. The plane is perpendicular to the optical axis of the reflected light. Therefore, even if the exposure position on the photoreceptor moves due to magnification change, normal exposure can be performed at the desired magnification.

Therefore, variable magnification copying can be performed using an inexpensive lens and a simple mechanism that minimizes the number of mirrors.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of the vicinity of an optical device and a belt-shaped photoreceptor of a copying machine according to an embodiment of the present invention. Belt-shaped photoreceptor, light source lamp, first mirror, second mirror, third mirror, fixed focus lens, fourth mirror

Claims (1)

[Claims] (1) A photoreceptor is provided in the center of the copying machine body, and a light source lamp and a first mirror are provided on the upper part of the copying machine body, which run under the fixed document table, and a fixed document disposed below the fixed document table. a focusing lens, a second mirror and a third mirror that guide the document reflected light from the first mirror to the fixed focus lens;
A copying machine including an optical device including a mirror and a fourth mirror that guides the original reflected light that has passed through the fixed focus lens to the photosensitive member, wherein the fixed focus lens and the fourth mirror are connected to the fourth mirror. The photoreceptor is movable in parallel along the optical axis of the original reflected light from the third mirror, and the area where the original reflected light from the movement range of the fourth mirror is irradiated is set to the original reflected light. A copying machine characterized by a belt-shaped photoreceptor that forms a plane perpendicular to light.