JP2505405B2 - Photoreceptor and electrostatic recording device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoconductor preferably used for reversal development and an electrostatic recording apparatus provided with this photoconductor.

BACKGROUND ART It is generally widely used to construct a printer by combining an exposure system such as a laser optical system, a liquid crystal shutter, an LED array, a CRT, an optical fiber, and a magneto-optical element with an electrophotographic device. In such a case, reversal development is adopted for reasons such as fatigue of the photoconductor, simplification of optical system control, and cost reduction of the optical scanning system. In such reversal development, so-called bias development is used in which toner is attached to a portion where light is applied and electric charges are removed. It should be noted that an alternating current, a direct current, or a combination of both is applied to this developing bias.

By the way, the photosensitive layer is difficult to be vapor-deposited or coated on both ends of the photosensitive member, so that the layer thickness is thin. Therefore, both ends of the photoconductor are less likely to be charged by the main discharger, so that the toner adheres excessively during reversal development. As a result, the inside of the machine is contaminated, and the toner adheres to the portion of the copy paper other than the developing portion to be contaminated. Further, the toner enters the discharger and causes electric leakage. Therefore, in order to solve such a problem, conventionally, the width of the photoconductor is made larger than the maximum width of the copy paper, the developing width is limited, and further, the copying width is regulated. This prevents toner from adhering to both ends of the photoconductor. However, in such a prior art, the size of the device is increased and the cost is increased.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The present invention solves the above technical problems and prevents excessive adhesion of toner to both ends of a photoconductor during reversal development with a simple structure without increasing the size of the apparatus. It is an object of the present invention to provide a photoconductor and an electrostatic recording device.

MEANS FOR SOLVING THE PROBLEMS The present invention relates to a reversal development type electrostatic latent image forming method for visualizing a portion of an electrostatic latent image formed by removing charged charges of a photosensitive layer on a surface of a photosensitive member. A photosensitive member used in a recording apparatus, comprising: an effective portion, which is located in a substantially central portion of the photosensitive layer in a direction perpendicular to a traveling direction of the photosensitive layer, and on which an electrostatic latent image is formed; And both end portions on both sides of the effective portion in the direction perpendicular to the area where an electrostatic latent image is not formed, and coat portions formed on the surfaces of the both end portions and having a volume resistance value equal to or higher than the effective portion. It is a characteristic photoconductor.

The present invention also provides an effective portion of the photosensitive layer, which is located substantially in the center of the photosensitive layer in the direction perpendicular to the traveling direction, on which an electrostatic latent image is formed, and the effective portion in the direction perpendicular to the traveling direction of the photosensitive layer. Located on both sides of the part, where no electrostatic latent image is formed,
A photoreceptor having a coat portion formed on the surfaces of both ends and having a volume resistance value equal to or higher than the effective portion; charging means for charging the photoreceptor; and the photoreceptor charged by the charging means. Exposure means for exposing, reversal developing means for visualizing the charge-removed portion of the electrostatic latent image formed by the exposure means, and the surface of the photoconductor by the reversal developing means. And a means for removing the electric charge from the coat portion after the development of the electrostatic recording apparatus.

Action According to the present invention, the coated portion having a volume resistance value equal to or higher than the effective portion is formed on both end surfaces of both sides of the effective portion of the photosensitive layer. This prevents the toner from excessively adhering to the surfaces of the both end portions during the reversal development.

According to the invention, a photosensitive member having a coat portion having a volume resistance value equal to or higher than the effective portion is formed on both end surfaces on both sides of the effective portion of the photosensitive layer, charging means for charging the photosensitive member, and An exposing unit for exposing the photosensitive member, a reversal developing unit for developing the portion where the charge is removed by the exposure, and a unit for removing the charge on the coated portion after development are provided. As a result, it is possible to reliably eliminate the electric charges accumulated and increased at both ends of the photoconductor.

Embodiment 1 FIG. 1 is a perspective view of a photoreceptor 1 according to an embodiment of the present invention. The photoconductor 1 has a photoconductive layer formed on the surface of a photoconductor drum having a right cylindrical shape, and is rotatable around an axis line 2 of the photoconductor 1 in the directions of arrows 3. A charging corona discharger 4 is arranged facing the surface of the photoconductor 1. The corona discharger 4 extends from one end of the photoconductor 1 to the other end thereof substantially in parallel with the axis 2. At both ends of the photoconductor 1 in the width direction, coat parts 5 and 6 that are charged to the same polarity as the corona discharger 4 are formed. The coat portions 5 and 6 are coated with a material having a volume resistance value equal to or higher than that of the photoconductor 1, for example, polyester resin. Therefore, as shown in FIG. 2, the potentials of the coated portions 5 and 6 are equal to or higher than the dark potential in the effective vapor deposition width 1 of the photosensitive layer of the photoreceptor 1. Therefore, the charged potential at both ends can be kept high without widening the width l2 of the photoconductor 1.

FIG. 3 is a simplified cross-sectional view of the vicinity of the photoconductor 1 of the electrostatic recording device 8 in which the photoconductor 1 is used. In the electrostatic recording device 8, so-called reversal development is performed in which the toner is attached to the portion where the charge is removed by irradiating the region charged by the charging corona discharger 4 with light. A charging corona discharger 4 is arranged on the upstream side of the exposure area 10 of the photoconductor 1 in the arrow 3 direction. Prior to the exposure of the photoreceptor 1 in the exposure area 10, the surface of the photoreceptor 1 is charged by the charging corona discharger 4 to a suitable polarity of the photoreceptor 1, for example, positive. The photoconductor 1 rotates and runs in the direction of arrow 3, and light is irradiated on the exposure area 10 through the optical system 11, and charges are removed at this irradiation portion to form an electrostatic latent image. A magnetic brush developing device 12 is provided downstream of the exposure area 10 in the arrow 3 direction.

The developing sleeve 15 of the magnetic brush developing device 12 is a bias source.
A voltage is applied by 16 so as to have the same polarity as the charging polarity of the photoconductor 1, and the bias source 16 causes the toner in the magnetic brush developing device 12 to adhere to the irradiated portion of the photoconductor 1. A toner image is formed. This toner image is transferred to the copy paper by the transfer corona discharger 13, and the transferred copy paper is separated by the charge elimination corona discharger 14 and conveyed to a heat fixing device (not shown). It During copying, the center of the photoconductor 1 in the width direction and the center of the copy paper are conveyed so that the center of the electrostatic latent image of the document along the width direction of the photoconductor 1 is the photoconductor 1. The image is formed so as to match the center position in the width direction of.

FIG. 4 is a plan view of the photoconductor 1 and the developing sleeve 15. The Mylar film 30 is wound around both ends of the developing sleeve 15 by a width l3 corresponding to the coat portions 5 and 6. This prevents the toner from falling even if the toner adheres to the regions of the developing sleeve 15 where the magnetic field is small at both ends. Even when such a my film 30 is provided, the toner flies in the arrow direction at both ends of the photoconductor 1 and, therefore, when the coat parts 5 and 6 are not provided, the both ends thereof are not formed. The toner adheres to the area, and a suitable reversal development cannot be performed. Therefore, in this embodiment, the coat portions 5 and 6 are provided to prevent the toner from adhering to both end portions of the photoconductor 1. Further, although the coat portions 5 and 6 are charged with electric charges by continuously performing the copying operation, the charged corona discharger 14 removes the charged electric charges of the coat portions 5 and 6. Therefore, the charge is accumulated in the coated portions 5 and 6 to prevent the coated portions 5 and 6 from being accumulated.
No spark is generated between the case and the cases of the dischargers 4, 13 and 14, and therefore, the photoreceptor 1 is prevented from being damaged by the spark. Further, it is possible to prevent the generation of noise due to sparks and the malfunction of the electronic circuit caused by the noise. After the transfer, the electric charge charged to the effective vapor deposition width 1 of the photoconductor 1 is discharged by the discharging lamp 60 and the discharging lamp 60.

FIG. 5 is a perspective view of another embodiment of the present invention. This embodiment is similar to the previous embodiment, and corresponding parts bear the same reference numerals. In this embodiment, the copy paper is conveyed with reference to the one end H of the photoconductor 1. It should be noted that, in this embodiment, the charge-eliminating corona discharger 14 in the above-described embodiment is not used, and the guide piece 40 is provided near the transfer corona discharger 13 along the coat parts 5 and 6 of the photoconductor 1. , 41 are provided. Guide piece
40 and 41 are configured so as to be able to contact or come close to the cord portions 5 and 6. The guide pieces 40, 41 are made of a conductive material such as a polyester film with a thin metal layer deposited on the surface thereof.
Therefore, when the photoconductor 1 rotates, the photoconductor 1 guides the guide pieces 40, 41.
The coat parts 5 and 6 are not damaged even if they come into contact with.

The guide pieces 40, 41 are grounded. Therefore, the charges of the coat portions 5 and 6 are eliminated by coming into contact with the guide pieces 40 and 41.

The guide piece 40 includes an arc portion 40a having substantially the same curvature as that of the photoconductor 1 and an extending portion extending from the arc portion 40a.
Including 40b and. The end of the extending portion 40b extends to the vicinity of the transport roller 35. Therefore, the copy paper after the transfer is separated by the guide piece 40 and conveyed to the conveying roller 35. The guide piece 41 is an arc portion having the same curvature as that of the photoconductor 1.
It consists of 41a only. Therefore, the guide piece 41 has only the function of removing static electricity, not the function of separating the copy paper.

Note that the guide piece 41 may have the same structure as the guide piece 40 so as to have a function of separating the copy paper and a function of removing the charge.

Effect According to the present invention, the coated portion having a volume resistance value equal to or higher than the effective portion is formed at both ends of the effective portion of the photosensitive layer, so that the coated portion can be formed at the time of reversal development with a simple structure and at low cost. It is possible to prevent the toner from adhering.

Further, according to the present invention, after the surface of the photoconductor is developed, the coated portion of the photoconductor is destaticized, so that the adhesion of toner to the coated portion can be prevented more reliably. In addition, it is possible to prevent the inside of the machine body from being soiled, and to prevent undesired adhesion of the toner to a portion of the copy paper other than the developing portion to deteriorate the copy quality. Moreover, since the toner does not excessively adhere to the coating portion, there is no problem that the toner enters the discharger or the like and causes electric leakage.

[Brief description of drawings]

FIG. 1 is a perspective view of a photosensitive member 1 according to an embodiment of the present invention, FIG. 2 is a graph showing the potential of the photosensitive member 1, and FIG. 3 is a photosensitive member of an electrostatic recording device 8 in which the photosensitive member 1 is used. 1 is a simplified sectional view of the vicinity of FIG. 1, FIG. 4 is a plan view of the photoconductor 1 and the developing sleeve 15, and FIG. 5 is a perspective view of another embodiment. 1 ... Photoconductor, 2 ... Axis, 3 ... Arrow, 4 ... Charging corona discharger, 8 ... Electrostatic recording device, 12 ... Magnetic brush developing device, 13 ... Transfer corona discharge Electric appliances, 14 …… Corona discharger for static elimination, 15 …… Development sleeve, 16 …… Bias source, 40, 41 …… Guide pieces

Claims (2)

(57) [Claims] 1. A photosensitive member used in a reversal development type electrostatic recording apparatus which visualizes a portion of an electrostatic latent image formed by removing a charged electric charge of a photosensitive layer on a surface of a photosensitive member. A body, an effective portion positioned substantially in the center of the photosensitive layer in a direction perpendicular to the traveling direction of the photosensitive layer, and an electrostatic latent image being formed; and the effective portion in a direction perpendicular to the traveling direction of the photosensitive layer. 1. A photoconductor, characterized in that it has both end portions which are located on both sides of the portion and on which an electrostatic latent image is not formed, and coat portions which are formed on the surfaces of the both end portions and have a volume resistance value equal to or higher than the effective portion. 2. An effective portion of the photosensitive layer, which is located substantially in the center of the photosensitive layer in a direction perpendicular to the traveling direction, on which an electrostatic latent image is formed, and the effective portion in a direction perpendicular to the traveling direction of the photosensitive layer. A photosensitive member having both end portions on both sides of the electrostatic latent image where an electrostatic latent image is not formed, and a coating portion formed on the surfaces of the both end portions and having a volume resistance value equal to or higher than the effective portion, and charging the photosensitive member. Charging means, exposing means for exposing the photoreceptor charged by the charging means, and a portion of the electrostatic latent image formed by removing the charges by the exposing means from which the charges are removed. An electrostatic recording apparatus comprising: a reversal developing means for developing a visible image; and a means for destaticizing the coat portion after the surface of the photoreceptor is developed by the reversal developing means.