JPS60138573A - Erasing device of copying machine - Google Patents

Abstract

PURPOSE:To eliminate the need to install an erasing lamp and take a preventive countermeasure to flare light which exerts evil influence upon an electrostatic latent image on the surface of a photosensitive body by guiding the flare light to an erasure area and irradiate the area. CONSTITUTION:The erasing device eliminates residual charges on the photosensitive body 1 and consists of a guide irradiating means 3 fitted near the optical path of an optical system 2. The optical system 2 guides light with which an original surface is irradiated to an exposure area alpha on the photosensitive body to irradiate it, and consists of an exposure lamp 5 positioned below platen glass 4 where the original is placed mirrors 6a-6e which guide and project reflected light of the lamp 5 from the original upon the area alpha, a projection mirror 7, and an image forming lens 8 which forms an image of the projection light upon the area alpha. The means 3 guides the flare light diffused from the optical path in the optical system 2 to irradiate an erasure area beta on the photosensitive body 1 provided between an electrostatic charging device 9 and a cleaning device 10.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an erasing device for a copying machine, and particularly to an erasing device applied to a slit exposure type copying machine.

[Prior art]

When copying using a slit exposure type copier,
After a uniform charge is applied to the surface of the photoconductor by a charging device, light from an exposure lamp that scans the document surface is projected and exposed, and an electrostatic latent image corresponding to the document image is formed. After completing the prescribed development, transfer, and cleaning steps, the surface of the photoconductor is then erased by an erase device installed near the photoconductor in order to re-form an electrostatic latent image corresponding to the next document image (2). The structure is such that residual charges on the surface are removed.

By the way, the above erase device uses a tungsten lamp,
Generally, a device is equipped with an eraser lamp consisting of a fluorescent lamp or a neon lamp, and is configured to irradiate the erased area on the photoreceptor with this light.
The installation of the eraser lamp required extra space, and there was also a problem in terms of power consumption.

For this reason, among slit exposure type copying machines, the exposure lamp is fixed and the platen glass moves, so-called.
Some copying machines with a moving platen use the light from an exposure lamp installed for exposing documents as erase light, so a reflector is installed outside the optical path for forming an electrostatic latent image to directly guide the light from the exposure lamp. A method has also been proposed in which the erased area is irradiated.

However, this type of erase device has the drawback that it cannot be applied to other slit exposure types, such as mirror moving types (2) where the exposure lamp and optical system move in a complicated manner.

[Purpose of the invention]

The present invention aims to eliminate various problems in the conventional erase device described above, and more specifically, removes residual charges by using unnecessary flare light generated in the optical path of an optical system. To provide an economical and compact erasing device for a copying machine that can perform

[Structure of the invention]

That is, the erasing device of the copying machine of the present invention guides the flare light diffused from the optical path to the vicinity of the optical path of the optical system provided for guiding and projecting the light irradiated onto the document surface onto the photoreceptor. The structure includes a guiding irradiation means for irradiating the erase area on the photoreceptor, and the guiding irradiation means:
Since unnecessary flare light that acts on the electrostatic latent image and has an adverse effect is used as erase light for removing residual charges, an erase lamp is not particularly required.

〔Example〕

Hereinafter, an erase device for a copying machine according to the present invention will be described based on an embodiment shown in the accompanying drawings.

FIG. 1 shows an erase device applied to a moving mirror copying machine according to an embodiment (1) of the present invention. The system (2) consists of two attached guiding irradiation means (3) near the optical path.

The optical system (2) guides and projects the irradiated light onto the exposure area (α) on the photoreceptor (1), and includes a platen glass (4) on which the document is placed. an exposure lamp (5) located below the exposure lamp (5), and first to fifth mirrors (6a) to (6e) that project the light reflected from the document by the exposure lamp (5) onto the exposure area (α) (secondary guidance); and a projection mirror (7), and an imaging lens (8) for forming an image of the guided projection light onto the exposure area (α).

The guiding irradiation means (3) directs flare light diffused from the optical path onto the erase area (β) on the photoreceptor (1) provided between the charging device (9) and the cleaning device (lO). As shown in Fig. 2, it is made up of a rectangular reflecting plate (11) made of a material with high reflectance such as C2, aluminum, etc. 2. A slit (1) is formed for passing the projection light.

In this embodiment, the reflector plate (1) is provided on the optical path between the fifth mirror (6e) and the projection mirror (7), and the flare light is reflected by the reflector plate (11). After the erase area (β) (1), move the optical axis (
They are placed at a fixed angle to each other.

Therefore, according to the above embodiment, when the copy start button (not shown) is pressed, the optical system (2) is activated and the exposure lamp (5) is turned on, and the driving device (not shown) (2) causes the exposure lamp (5) to turn on.
) scans the original while reciprocating along the platen glass (8) surface (- (Fig. 3). The light reflected on the original passes through the optical path and passes through the exposure area (α) (directed towards -). However, the flare light that is diffused on the optical path and may have an adverse effect on the exposed area (α) is reflected by the reflector (11) and guided downward, as shown in Figure 4 (2). and irradiates the erase area (β) of the photoreceptor (1).

Therefore, on the surface of the photoreceptor (1) passing through the erase area (β), residual charges are removed by this light, so that a uniform zero potential is formed.

On the other hand, the projection light that has passed through the reflection plate (111) (121) is guided and projected onto the exposure area (α) of the photoreceptor (1). Therefore, the erase area (7) has a uniform zero potential. Afterwards, on the surface of the photoreceptor (1) to which a predetermined charge is applied by the charging device (9), an appropriate electrostatic latent image corresponding to the original image is formed in the exposed area (α).

As a result, the residual charge on the photoreceptor (1) can be removed without the need to provide an erase lamp (= it is also possible to prevent harmful flare light from entering the exposure area (α)). It's turning.

In addition, although the said guidance irradiation means (3) is comprised from the rectangular reflection plate (11) in this Example, it is of course not limited to this. Furthermore, although the erase device of this embodiment is applied to a moving mirror copying machine (1), the present invention is not limited to this, and can be applied to other types of copying machines as long as they are of slit exposure type. be.

〔Effect of the invention〕

The erasing device of the copying machine of the present invention generates the erase near the optical path,
In order to proactively utilize flare light, which has a negative effect on the electrostatic latent image on the surface of the photoreceptor, the flare light is guided and irradiated onto the erase area, eliminating the need for an erase lamp and at the same time, There is no need to take measures to prevent flare light, which is economical and has the effect of increasing space efficiency.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an erasing device for a copying machine according to the present invention;
FIG. 2 is a plan view of a reflecting plate constituting the guided irradiation means according to the present invention, FIG. 3 is an explanatory diagram showing when the optical system in FIG. 1 scans an original, and FIG. It is an optical path diagram showing the course of light. Explanation of symbols (1)...Photoreceptor (2)...Optical system (3)...Guiding irradiation means (4)...
Platen glass (5)...Exposure lamp (9)
...Charging device (lO) ...Cleaning device
(11)...Reflector plate (1)...Slit (α)...Exposure area (β)...Erase area Patent applicant Fuji Xerox Co., Ltd. Agent: Tomohiro Donakamura, Patent Attorney, Katsuo Naruse, Figure 1, Figure 2, Figure 3, Figure 4

Claims (1)

[Claims] In a copying machine equipped with an optical system that guides and projects light irradiated onto a document onto an exposure area on a photoreceptor, a flare light diffused from the optical path is guided near the optical path formed by the optical system, An erasing device for a copying machine, characterized in that a guiding irradiation means is provided for irradiating an erase area on the photoreceptor.