JPH10213978A - Electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an electrophotographic device capable of transferring a fine toner image to paper as it is and suited to realize high resolution and high printing quality by providing an optical discharge device and a corona discharge device impressing corona the polarity of which is reverse to toner between a developing device and a transfer device. SOLUTION: The toner 7 developing-processed by the developing device 2 is transferred to the paper 6 by the transfer device 5. The toner 7 after developing exists inside the electrostatic latent image of a photoreceptor 1 and is partially scattered to a part out of the electrostatic latent image as the potential of the photoreceptor 1 at a non-exposure part is discharged by an erasing lamp 3. Thereafter, only one layer of the toner 7 is electrostatically charged to have the reverse polarity by a pretransfer corona 4, so that the toner scattered to the part out of the electrostatic latent image is not transferred to the paper 6. However, the toner 7 inside the electrostatic latent image is easily transferred to the paper 6 because restricting force by the electrostatic latent image is eliminated. Thus, the fine toner image is transferred to the paper 6 as it is.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic apparatus.

[0002]

2. Description of the Related Art In a conventional electrophotographic apparatus employing reversal development, a structure (structure) in which a development process is directly shifted to a transfer process after the development process as shown in FIG. 3 or a development process as shown in FIG. After that, a configuration (configuration) in which the process shifts to a transfer process via a static elimination process by an optical static eliminator (erase lamp),
Further, as shown in FIG. 7, after the development process, there is known a configuration (configuration) in which the process shifts to the transfer process through a charge removal process by a corona charge removal device (pre-transfer corona) that applies a corona having a polarity opposite to that of the toner. Have been.

[0003]

By the way, in the case of the above structure, even if a slight disturbance of the electrostatic latent image occurs due to the developing device as shown in FIG. 4, the electrostatic latent image formed by the exposure device is generated. Since the toner image developed into the image is transferred to the paper by the transfer device, there is an advantage that the disturbance of the toner image is small, that is, the print quality is high. However, the toner image is electrostatically pressed against the photoreceptor due to the reversal development in which the development is performed by the potential difference between the exposed portion and the non-exposed portion, and particularly the transferability of the thin line portion toner image to the paper is reduced. In addition, since the charging level of the photoreceptor in the non-exposed area is high, the electrostatic attraction force between the photoreceptor and the paper charged to the opposite polarity by the transfer device is increased, and the paper is easily wound around the photoreceptor. .

Further, in the case of the above configuration, as shown in FIG. 6, since the potential of the photosensitive member in the non-exposed portion can be eliminated to the residual potential, the electrostatic attraction force with the paper in the transfer device is reduced, and The problem that paper is wrapped around is less likely to occur.
Further, there is an advantage that the transferability of the toner in the thin line portion can be improved. However, in the case of the configuration, in order to eliminate static electricity in the non-exposed area, that is, the periphery of the toner image, the toner particles pushed in as a toner image due to the potential difference between the exposed and non-exposed areas have the same polarity and repel each other. However, there is a disadvantage in that the print quality is deteriorated by scattering around the image.

Further, in the case of the above configuration, as shown in FIG. 8, since a corona having a polarity opposite to that of the toner, that is, a polarity opposite to the charging of the photoreceptor and a polarity same as the charging of the paper is applied, similarly to the configuration, a non-corona is applied. The potential of the photoreceptor in the exposed portion can be eliminated, and the polarity of a toner image of about one layer can be inverted with an appropriate amount of application. Therefore, the toner particles scattered around the image described in the configuration can be charged to the same polarity as the paper, and the transferred toner image has an advantage that a good print quality without scattering around the toner image can be secured. However, while it is possible to set a margin for the variation in the amount of light of the erase lamp of the configuration, which is more than a certain required amount of light, if the applied amount of the corona of the pre-transfer corona of the configuration is too large, it can be developed in multiple layers. The optimum value is that all the layers of the applied toner are charged to the opposite polarity, and the transferability to the paper is deteriorated. Therefore, the setting margin is low, and as a result, the pre-transfer corona maintenance cycle is short.

Accordingly, each of the prior art configurations has advantages and disadvantages. Under these circumstances, there is a demand for higher resolution and higher print quality in electrophotographic devices, and in order to meet this demand, a technology for transferring minute toner to paper in the form as it is is necessary. I have.

SUMMARY OF THE INVENTION It is an object of the present invention to transfer a fine toner image to a sheet in a form as it is.
An object of the present invention is to provide an electrophotographic apparatus suitable for high printing quality.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to reversely develop an electrostatic latent image formed on a photoreceptor using toner, and transfer a toner image formed on the photoreceptor by the reversal development to a transfer device. In an electrophotographic apparatus for transferring to a recording material, this is achieved by providing a light neutralizing device and a corona neutralizing device for applying a corona having a polarity opposite to that of the toner, between the developing device and the transfer device.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of the electrophotographic apparatus of the present invention. In the electrophotographic apparatus, a developing device 2, an erase lamp 3, a pre-transfer corona 4, and a transfer device 5 are arranged around a photoconductor 1 having photoconductivity, and a toner 7 developed by the developing device 2 is transferred to a transfer device. At 5, it is transferred to paper 6.

FIG. 2 shows the potential behavior and charging behavior of the photosensitive member 1 and the toner 7 of the present invention. The toner 7 after the development is inside the electrostatic latent image of the photoconductor 1 as shown by A, but the electric potential of the photoconductor 1 in the non-exposed portion is removed by the erase lamp 3 as shown by B, and the toner is removed. 7 scatters outside the electrostatic latent image. Thereafter, the pre-transfer corona 4 charges the toner 7 by one layer to the opposite polarity (toner 8 charged to the opposite polarity), so that the toner 8 scattered outside the electrostatic latent image cannot be transferred to the paper 6.

However, the toners 7 and 8 inside the electrostatic latent image are
Since there is no binding force due to the electrostatic latent image, the image is easily transferred to the paper 6.

[0012]

As described above, according to the present invention, it is possible to provide an electrophotographic apparatus suitable for high resolution and high print quality, in which a minute toner image can be transferred as it is to a sheet. be able to.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an electrophotographic apparatus of the present invention.

FIG. 2 is an explanatory view showing the concept of printing of the potential behavior and charging behavior of a photoconductor and toner of the electrophotographic apparatus of the present invention.

FIG. 3 is a schematic configuration diagram of a conventional electrophotographic apparatus.

FIG. 4 is an explanatory diagram showing the concept of printing of the potential behavior and charging behavior of the photoconductor and toner of the electrophotographic apparatus of FIG. 3;

FIG. 5 is a schematic configuration diagram of another electrophotographic apparatus of the related art.

FIG. 6 is an explanatory diagram showing the concept of printing of the potential behavior and charging behavior of the photoconductor and toner of the electrophotographic apparatus of FIG.

FIG. 7 is a schematic configuration diagram of another conventional electrophotographic apparatus.

FIG. 8 is an explanatory diagram showing the concept of printing the potential behavior and charging behavior of the photoconductor and toner of the electrophotographic apparatus of FIG.

[Explanation of symbols]

1 is a photoreceptor, 2 is a developing device, 3 is an erase lamp (optical neutralizing device), 4 is a pre-transfer corona (corona neutralizing device), 5 is a transfer device, 6 is paper, 7 is toner, and 8 is charged to the opposite polarity. Toner.

Claims (2)

[Claims] An electrophotographic apparatus in which an electrostatic latent image formed on a photoreceptor is reversely developed using toner and a toner image formed on the photoreceptor by the reverse development is transferred to a recording material by a transfer device. An electrophotographic apparatus, further comprising a light neutralizing device and a corona neutralizing device for applying a corona having a polarity opposite to that of the toner, between the developing device and the transfer device. 2. An electrophotographic apparatus according to claim 1, wherein said photo-static eliminator is provided upstream of the corona eliminator in the photoconductor moving direction.