JPH0212173A - Image forming device - Google Patents

Abstract

PURPOSE:To individually or synthetically form the image of a document and the image obtained by the modulation of laser light and to read the image in one device by using an optical path switching means and a laser light emitting means, reflecting the laser light on the surface of the document and conducting it to a photosensitive body by an optical system. CONSTITUTION:By turning on and off the laser light based on the image information and making the surface of the document D a white reflecting surface, a latent image based on the on/off of the laser light can be formed on the photosensitive body 10. By setting the optional document D and turning on and off the laser light based on the image information, the synthesized image of the image of the document and the image by the laser light is formed on the photosensitive body 10 as the latent image. Meanwhile, when the optical path switching means 25 is switched to an image sensor 20 side, the laser light reflected on the surface of the document D is formed into the image on the image sensor 20 and the image of the document can be read by the image sensor 20. Thus, the image of the document and the image obtained by the modulation of the laser light can be individually or synthetically formed in one device and also the image of the document can be read.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image forming apparatus such as a copying machine or a laser beam printer.

Conventional technologies and their problems In general, image forming devices that form a latent image on a photoreceptor by exposure to light containing image information and visualize that image on paper utilize reflection from the surface of the document. electrophotographic copying machine,
2. Description of the Related Art Laser beam printers that use on/off of laser light as image information are known. These differ only in the exposure method, and other image forming parts including the image exposure section can be used in common.

Therefore, Japanese Patent Application Laid-open No. 54-25736 proposes an image forming apparatus which is equipped with an exposure means using light reflected from the document surface and an exposure means using laser light, and which share other image forming parts. . With this device, it is possible to selectively form an image using the light reflected from the document surface and the laser light.

However, in this device, the light source reflected from the original surface and the laser beam are separated, and the optical path is also different except for the final stage, so it is difficult to form a composite image using the reflected light from the original surface and the laser beam at the same time. The problem is that it is impossible.

On the other hand, in recent years, various image sensors that read optical image information have been developed and are used as image storage devices with facsimile and editing functions.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to enable a single device to form an image of a document and an image obtained by modulating the laser beam itself, or a combination of both, and also to read the document image. .

Means for Solving the Problems In order to solve the above problems, an image forming apparatus according to the present invention includes (a) a laser light emitting means as a light source, and (b) a laser beam emitted from the light emitting means on a document surface. (c) an image sensor installed at a position equivalent to the image forming surface on the photoreceptor; (d) [laser light reflected on the surface of the photoreceptor]; and means for switching the optical path so that the light illuminates either the photoreceptor or the image sensor.

In other words, in the above configuration, if the optical path switching means is set to be switched to the photoreceptor side, the laser beam from the laser emitting means is always on and reflected from the document surface, so that the original image is transferred to the photoreceptor side. A latent image of the document image is formed. In addition, the laser light is turned on according to the image information,
By turning off the laser beam and making the document surface a white reflective surface, a latent image is formed on the photoreceptor based on whether the laser beam is on or off. Further, by setting an arbitrary document and turning the laser beam on and off based on image information, a composite image of the document image and the laser beam image is formed as a latent image on the photoreceptor.

On the other hand, if the optical path switching means is switched to the image sensor side, the laser beam reflected from the document surface is imaged on the image sensor, and the document image is read by the image sensor.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an image forming apparatus according to the present invention will be described below with reference to the accompanying drawings.

In Figure 1, (1) is the document table glass, and arrow (a)
It is possible to scan in the direction. Note that FIG. 1 shows the scan in progress. (2) is a laser scanning device, which is composed of a laser diode (not shown), a lens system, a polygon mirror (3) for beam scanning, and a driving circuit thereof. (
4) is a mirror, and (5) is a lens array in which converging light transmission bodies (trade name: SELFOC) are arranged in parallel. The laser light emitted from the laser diode is scanned by each reflective surface of the polygon mirror (3) that is rotationally driven, and is scanned by the mirror (4).
) placed on the document platen glass (1).
) or reflected from the back side of the document holding cover (not shown),
The photoreceptor drum (10) is exposed through the lens array (5). The laser diode is turned on and off via a drive circuit based on an image signal from an image control section of a computer. The polygon mirror (3) is also driven to rotate at a constant frequency. Such control of image signals is well known, and its details will be omitted.

On the other hand, (20) is an image sensor, and the photoreceptor 10
) is provided at a position equivalent to the imaging plane on the top. As shown in FIG. 2, this image sensor (20) is a contact type CCD linear image sensor in which five sensor chips (20a) each having a large number of pixels are arranged in a staggered manner. (25)
1 is an optical path switching mirror, which can be switched between the solid line position and the dotted line position in FIG. 1 based on turning on and off a solenoid (not shown). The solenoid is normally turned off, and at this time the mirror (25) maintains the solid line position, and the reflected light from the document surface forms an image on the photoreceptor (10). Further, when the solenoid is turned on, the mirror <25> is switched to the dotted line position, the reflected light from the document surface forms an image on the image sensor (20), and the document image is read. The image read in this manner is transmitted through a communication circuit when the apparatus is used as a facsimile machine, for example. Also,
The read image can also be stored in the image control section of the laser scanning device (2) through the interface.

In this case, the memorized image can be output as a modulated laser beam from the laser scanning device (2) and formed as an image on the copy paper (P) by this device, as detailed below. be.

The photosensitive drum (10) can be rotated in the direction of arrow (b), and around it is an eraser lamp (
11), an electrostatic charger (12), a magnetic brush developing device (13), a transfer charge (14), and a residual toner cleaning device (15). Copy paper (P) is placed in an automatic paper feed cassette. The paper is fed one by one from the transfer charger (14) and the photoreceptor drum (10).
), the toner image is transferred,
Thereafter, it is conveyed to the left, and the toner is thermally fixed by a fixing device (17).

Next, a case will be described in which an image is formed on copy paper (P) in the above configuration. In this case, the mirror (
25) is set at the solid line position in FIG.

First, when printing out images using laser light,
As shown in Figure 3 (a-1), place a white original (D) on the original table glass (1) and use it as a reflective surface, or use the back side of the original cover (not shown) as a reflective surface. When activated, image information is output from the laser diode. for example,
The laser diode is turned off when scanning the circular image area (X) shown in FIG. 3 (a-2), and is turned on when scanning the background area (Y) shown with diagonal lines in the other figures. . With this, the image shown in FIG. 3 is placed on the photosensitive drum (10).
As shown in a-3), an electrostatic latent image is formed in which the charges in the image area (X) remain and the charges in the background area (Y) are erased.

Also, to print out the original image, select any original (
D) is placed on the document glass (1), the laser beam is always turned on, and the document glass (1) is scanned at a constant speed. For example, the original (D
) with the laser diode always on [Figure 3 (
b-2>], the charge of the image area (X) remains on the photosensitive drum (10) as shown in (b-3) in FIG. 3, and the charge of the background area (Y) remains. An electrostatic latent image with erased images is formed.

Furthermore, when printing out a composite image of the original with the laser beam image, place an arbitrary original (D) on the original platen glass (1) and move the original platen glass (1) at a constant speed. At the same time, the laser diode is turned on and off to output image information. For example, in Figure 3 (c
For the document (D) shown in -1), the laser diode is turned off in the area corresponding to the circular image area (X) shown in (c-2) in Figure 3, and in the area corresponding to the background area (Y) shown with diagonal lines. Turn on.

In this way, an electrostatic latent image is formed by combining the two images as shown in (c-3> in Figure 3).In this case, (X,)
The part is the part where the laser output is on, but because it is the original image part, a charge remains, and the part (X,) is the background part of the original, but the part where the laser output is off, so a charge remains, and the part (X,
) portion is the document image portion and the laser output off portion, and therefore charges remain, and charges are erased in the other portions (Y) as background portions.

By the way, the laser light that irradiates the document surface needs to be sufficiently focused in order to obtain good reproducibility of the document image.

If the beam is not narrowed down, the beam will often span both the white and black portions of the document, and the degree of scattering of reflections on the document surface will be large, resulting in poor image reproducibility.

Note that the image forming apparatus according to the present invention is not limited to the above-described embodiments, and can be variously modified within the scope of the gist.

For example, the laser beam may be directly irradiated onto the document surface without passing through the mirror (4). However, when the lens array (5) is installed as shown in FIG. 1, the efficiency is better as the incident angle of the laser beam with respect to the document surface is smaller. therefore,
It can be said that it is preferable to arrange the mirror (4) as shown in the figure to reduce the angle of incidence, since the optical system can be made smaller.

Furthermore, in terms of efficiency, it is better to form an optical path by tilting the lens array (5) in the direction of the dotted line.

On the other hand, the photoreceptor may be one that forms not only an electrostatic latent image but also a silver salt latent image.

Effects of the Invention As is clear from the above explanation, according to the present invention, a laser light emitting means is used as a light source, and the laser light is reflected from the document surface by a mirror and lens system and guided onto the photoreceptor. Not only can a single device form a document image and an image created by modulating laser light as a latent image on a photoreceptor,
A latent image can also be formed by combining both images.

In addition, an image sensor is installed at a position equidistant from the image formation surface on the photoconductor, and the optical path can be switched so that the laser light reflected from the document surface illuminates the image sensor, making it possible to read the image with the image sensor. It can also function as a facsimile and an image storage device.

[Brief explanation of the drawing]

The drawings show an embodiment of an image forming apparatus according to the present invention, in which FIG. 1 is a schematic configuration diagram, FIG. 2 is a plan view of an image sensor,
FIG. 3 is an explanatory diagram of the document surface, the output of the laser diode, and the latent image. (1)... Document glass, (2)... Loser operation device, (3)... Polygon mirror, (4>... Mirror,
(5)...Luns array, (10)...Photosensitive drum, (20)...Image sensor, (25)...Optical path switching mirror, (D)...Document.

Claims (1)

[Scope of Claims] 1. An image forming apparatus that forms a latent image on a photoconductor by exposure from a light source and visualizes the image on a sheet of paper, comprising: a laser emitting means as a light source; and from the light emitting means. an optical means for reflecting the emitted laser light on the surface of the document and forming an image on the photoreceptor; an image sensor installed at a position equivalent to the image formation surface on the photoreceptor; and a laser beam reflected on the surface of the document. 1. An image forming apparatus comprising: means for switching an optical path so that the light illuminates either a photoreceptor or an image sensor.