JPS6139420Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic apparatus that performs one copying operation during two rotations of a photoreceptor.

Conventionally, electrophotographic devices use a drum-shaped or belt-shaped photoreceptor, around which a charging device, an exposure device, a developing device, a transfer device, a static elimination device, a cleaning device, and a fatigue recovery device are arranged in order. Some devices perform one image forming operation by performing charging, exposure, development, transfer, neutralization, cleaning, and fatigue recovery during one rotation of the body. However, in such an electrophotographic apparatus, if a device that wipes the photoreceptor with a cleaning member is used as a cleaning device, the toner cleaned from the photoreceptor is discarded together with the cleaning member. It is not economical as it consumes too much. Furthermore, in a cleaning device that uses a brush or blade for cleaning, a large container is required to collect the toner cleaned from the photoconductor by the brush or blade, and a large container is required to collect the toner cleaned from the photoconductor by the brush or blade. In order to reuse the toner, it must be conveyed to the developing device manually or by a conveying mechanism, and since the cleaning device and the developing device are largely separated, this conveying device is large, complex, and expensive. Become.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks and to provide a small, simple, and inexpensive electrophotographic apparatus that can reuse toner that has been cleaned from a photoreceptor.

The present invention will be described below using examples with reference to the drawings.

As shown in FIG. 1, the photoreceptor 11 is formed into a drum shape, and around it is a charging device 12 and an exposure device 1.
3. The cleaning device 14, the developing device 15, the transfer device 16, and the fatigue recovery device 17 are sequentially arranged along the rotation direction of the photoreceptor 11. Note that the photoreceptor 11 can also be formed into a belt shape. The photoreceptor 11 is rotationally driven by a drive device at a predetermined speed in the direction of the arrow shown in the figure, and first, the entire surface is charged by a charging device 12, and an image of an object to be copied, that is, an original document is exposed by an exposure device 13. The exposure device 13 uses a slit exposure method of an original moving type or an optical system moving type. For example, a transparent document table 18 moves in synchronization with the photoreceptor 11, the light source 19 illuminates the document on the document table 18, and the light from the document passes through a reflecting mirror 20, a lens 21, and reflecting mirrors 22, 23, and 24. The photoreceptor 11 is exposed to light through the slit formed by the diaphragm member 25 to form an electrostatic latent image. Next, the electrostatic latent image on the photoreceptor 11 is developed by a developing device 15 using dry toner. For example, a magnetic brush developing device is used as the developing device 15, and a non-magnetic sleeve 26' containing a built-in magnet 26 and rotated at a predetermined speed by a driving device allows the developer 28 in the container 27 to be transferred to the photoconductor 1.
The electrostatic latent image on the photoreceptor 11 is developed with the toner in the developer. Non-magnetic sleeve 2
6', after the developer is supplied to the photoreceptor 11, the remaining developer is scraped off by a blade 29, and the toner is supplied from the toner supply device 10 into the container 27, and the toner and carrier in the container 27 are stirred. It is mixed by a blade 30. In addition, the photoreceptor 11 and the transfer device 16 are synchronized from the paper feeding device 31 to the photoreceptor 11.
A transfer paper 32 is fed in between the transfer paper 32 and the toner on the photoreceptor 11 is transferred onto the transfer paper 32 by the transfer device 16. The paper feeding device 31 uses, for example, a paper feeding roller 33 to send out a transfer paper 32 on a paper feeding table 34 in synchronization with the photoconductor 11, and the transfer paper passes through guide plates 35 to 39 and rollers 40 to 43 to the photoconductor 11. A device that is sent between the transfer device 16 and the transfer device 16 is used. The transfer paper on which the toner has been transferred is separated from the photoreceptor 1 by the separating claw 44.
It is peeled off from 1 and transferred to a fixing device 46 by a conveying device 45.
The paper is conveyed to the printer, the toner is fixed thereon, and the paper is discharged outside as a copy. In this way, each of the operations of charging, exposing, developing, feeding, and transferring are performed during one rotation of the photoreceptor 11. When the photoreceptor 11 makes one revolution next time, the document table 18 returns to its original position, and the photoreceptor 1
1 is cleaned by the cleaning device 14 and fatigue is recovered by the fatigue recovery device 17. During the second rotation of the photoreceptor 11, the above-mentioned charging, exposing, developing, paper feeding, and transferring operations are not performed. The cleaning device 14 uses a blade, for example, and is arranged above the magnet 26 . Toner is scraped off from the photoreceptor 11 by the blade 14, and the toner falls along the blade 14 onto the non-magnetic sleeve 26' due to its own weight and inertia, and is collected into the container 27 and reused. blade 1
For example, 4 is in constant pressure contact with the photoreceptor 11, so that when it comes into contact with the electrostatic latent image formed on the photoreceptor 11, it has such electrical insulation that it does not affect the electrostatic latent image. According to the required experiment about 10 ¹⁰
It is Ωcm or more. Furthermore, by appropriately selecting the specific resistance value of the blade 14, the surface potential of the non-image forming area of the photoreceptor 11 can be lowered and so-called background staining can be prevented. The above-described operation is performed while the photoreceptor 11 rotates twice, resulting in one image forming operation.

As described above, according to the electrophotographic apparatus according to the present invention, one copying operation is performed during two rotations of the photoreceptor, and the cleaning device is brought into contact with the photoreceptor below the developing position. The toner cleaned from the photoconductor can be reused in the development device by arranging the photoconductor and the developing device close together, and a large conveyance device is used to convey the toner cleaned and collected from the photoconductor to the development device. is not required, making the configuration simple, compact, and inexpensive. In addition, since the cleaning device uses a blade made of an electrically insulating material that does not leak the latent image that is always in pressure contact with the photoreceptor, a mechanism for bringing the cleaning means into contact with and separating it from the photoreceptor is unnecessary, simplifying the machine itself and preventing failures. It is possible to form a high-performance machine with less.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of an electrophotographic copying apparatus according to the present invention. 11...Photoreceptor, 12...Charging device, 13...
Exposure device, 14... Cleaning device, 15...
Developing device, 16... Transfer device, 31... Paper feeding device, 46... Fixing device.

Claims (1)

[Claims for Utility Model Registration] 1. At least a charging device, an exposure device, a developing device, a transfer device, and a cleaning device are arranged around a photoconductor, and the photoconductor is rotated twice to
In an electrophotographic apparatus that performs image forming operations twice, the cleaning device has a cleaning device that is disposed between the exposure device and the development device and comes into contact with the photoreceptor, and the cleaning device is a latent cleaning device. Electrophotography, characterized in that the blade is made of an electrically insulating material that does not leak images, and is in constant contact with the photoreceptor while the photoreceptor rotates for image forming operation. Device. 2. The electrophotographic apparatus according to claim 1, wherein the cleaning means comprises a blade that causes the toner scraped upstream of the developing device to flow down.