JPS6117166A - Electronic copying machine - Google Patents

Abstract

PURPOSE:To simplify a device to reduce the cost by using an exposure light source for the fatigue of a photosensitive body in common. CONSTITUTION:The exposure light source for image exposure is set and lit to obtain a required quantity of light for the fatigue of the photosensitive body even when a photosensitive drum 9 is rotated preparatorily, and this exposure light source is used also as an exposure light source for the normal copying cycle. Thus, the device is simplified, and the cost is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to the use of an image exposure optical system in the process of fatigue exposure applied to a photoreceptor of an electronic copying machine.

(Prior art) F'' I) C Electrophotography generally involves copying through the processes of charging, exposure, development, transfer, fixing, and cleaning, and as a photoconductive photoreceptor used in this process, When a high-sensitivity type is used, the initial fatigue during the copy cycle is large, which may cause density differences in the image.

In such cases, a process is known in which the photoreceptor is intentionally exposed to light during preliminary rotation to fatigue the photoreceptor, thereby eliminating the appearance of initial fatigue. A tungsten lamp is installed as an auxiliary lamp in addition to a static eliminator and an exposure increaser to remove the residual charge on the photoreceptor for the so-called fatigue process of applying light in advance.The lamp is turned on only during preliminary rotation and turned off during the copy cycle. . However, installing independent light sources to achieve each function such as image capture and fatigue,
This is undesirable because it occupies installation space, increases complexity, and increases manufacturing costs.

(Object of the Invention) The present invention utilizes a lamp for image exposure for a fatigue process. , and to reduce costs.

(Structure of the Invention) [1] In an electronic copying machine equipped with an image exposure device for a photoreceptor, when the photoreceptor is rotated in advance, the exposure light source of the image exposure optical system is Turn on the light source and adjust the light intensity of the exposure light source (
&' This is achieved by providing an electronic copying machine-1 characterized in that the exposure light source is different from the light 7 during exposure 1 and is used also for fatigue of the photoreceptor.

(Example) FIG. 1 is a schematic diagram of an embodiment of the present invention.

The original on the original platen 1 is exposed to the exposure lamp 2 and the first mirror 3.1.
The cleaning unit 2 is cleaned in advance through scanning of the optical system consisting of $2 mirror/l, tjS3 mirror 5, main lens 6, Agebuta lens 7, and fourth mirror 8.
An image is formed on the photosensitive drum 9, which is cleaned in step 2 and first neutralized by a static eliminator 21', then positively charged by a charging device 20, and the non-image area is erased again by a static eliminator 21, and the formed latent image is The toner in the developer negatively charged in the developing device 11 is transferred by a magnetic roller 12 to form a visible image. The second visible image is transferred onto the plain paper fed from the paper feed rollers 14 and 15 at the transfer section 23, transferred to the transfer paper conveyance section 16 at the peeling gls 23', and then thermally fixed at the fixing g17 to complete the copying. , paper ejection roller 1
It is recovered by 9.

As shown in FIG. 1, the exposure light source 2 for image exposure is set and turned on so as to provide the necessary amount of light for fatigue even during the preliminary rotation of the photoreceptor drum 9, and is used during the normal copy cycle. It can also be used as an exposure light source.

In addition, in an electronic copying machine with a movable light source and a fixed document table as in this embodiment, the home position, which is the stop position of the exposure light source, is located off the document table, for example, on the left side of the copying machine, as shown in FIG. Since it is set at the position shown in the figure and a white background portion 26 is provided there as a reversal surface, uniform fatigue light is irradiated onto the surface of the photoreceptor 5 during the first four-turn. The home position is preferably the position shown in figure ai, but if the position is outside the original size, even if it is set towards the edge of the document table, the white background 2 on the back of the document holding cover
6' can be used. But in this case,
When using an f-shaped original for the original, the degree of shading in the portion that exceeds the specified original size may appear on the home edge of the edge of the original plate, which may cause problems in forming fatigue exposures such as -. . Therefore, the home position is a position outside the document positioning reference line for each size document, and is located outside the document table.
The position shown in Figure 1 is suitable.

FIG. ptS2 shows one embodiment of a means for dividing the light amount of fatigue exposure during preliminary rotation of the exposure light source 2 and image exposure during the copy cycle. The light source lamp 2 is connected to a constant voltage device 33. The constant voltage device 33 consists of a drive circuit 30 and a differential amplifier 31, and a voltage cutter j+ device 34 is connected to the differential amplifier 31. The voltage switching device 34 includes voltage dividing resistors R, , R2, R3.
and a changeover switch 35. During preliminary rotation, the switch 35 is opened to increase the voltage supplied to the lamp 2. During image exposure, the switch is closed to lower the voltage supplied to the lamp. The on/off switch 35 is preferably constructed of a high-speed non-contact switch using a transistor.

Further, as another means for changing the amount of light, a slit may be provided in the exposure optical system and the inside of the slit may be changed, or a filter may be inserted or removed.

(Effects of the Invention) As explained in -1- below, the present invention provides a light source for image exposure that takes into consideration the difference between the amount of light required to impart fatigue to the electrophotographic photoreceptor and the amount of light for image exposure. This device is also used for physical fatigue, which makes it possible to simplify the device and reduce costs.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an embodiment of the present invention, and FIG. 2 is a schematic diagram of a light source voltage conversion circuit of the present invention. 2...Exposure lamp 26...White background reflector 26
'...White area on the back of the document table cover 30...Drive circuit: 31...Differential amplifier 33...Voltage regulator 34...Voltage switching device 35...Selector switch

Claims (1)

[Claims] 1) In an electronic copying machine equipped with an optical system for image exposure to a photoreceptor, an exposure light source of the image exposure optical system is turned on during preliminary rotation of the photoreceptor, and the light intensity of the exposure light source is adjusted during image exposure. 1. An electronic copying machine characterized in that the exposure light source is used also for fatigue of a photoreceptor, with a different amount of light compared to the above. 2) Claim 1 characterized in that the white background portion is continuously exposed during the preliminary rotation of the photoreceptor.
Electronic copying machine as described in section. 3) The electronic copying machine according to claim 2, wherein the input voltage of the exposure light source is changed to switch the amount of light from the exposure light source. 4) The electronic copying machine according to claim 2, wherein the amount of light is switched by changing the size of the slit in the exposure window of the exposure light source or by changing the filter.