Electrophotography – Control of electrophotography process – Control of transfer
Patent
1999-03-30
2000-09-05
Chen, Sophia S.
Electrophotography
Control of electrophotography process
Control of transfer
399 45, 399162, 399297, G03G 1516
Patent
active
061155624
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to an image forming device which transfers a toner image from a belt shaped toner image carrying member to a print sheet by means of a roller.
BACKGROUND OF THE INVENTION
In recent years such an image forming device of toner system as exemplified by a laser printer has been widely used to enable a clear image with excellent resolution to be produced.
Here, a prior art image forming device of quadrature transfer system will be first explained.
FIG. 9 is a diagrammatic sketch of a prior art image forming device of quadrature transfer system, FIG. 10 is a perspective view of the foregoing image forming device and FIG. 11 is a diagram to show the transfer state of an opposed transfer roller of the foregoing image forming device. In FIG. 9, FIG. 10 and FIG. 11, the reference symbol 1 is a photosensitive belt, the reference symbol 2 is a charging unit, the reference symbol 3 is an image developer, the reference symbol 3a is toner, the reference symbol 3b is an image development roller, the reference symbol 3c is a toner image, the reference symbol 4 is a photosensitive belt cleaner, the reference symbol 5 is a discharging unit, the reference symbol 6 is a light exposure unit, the reference symbol 7 is a print sheet, the reference symbol 8 is an opposed transfer roller, the reference symbols 9a to 9c are photosensitive rollers, the reference symbol 10 is a transfer plate and the reference symbol 11 is a print sheet transporting roller.
As shown in FIG. 9, a closed loop belt like shape photosensitive belt 1, the surface of which is coated with an organic photoconductive material, is supported by photosensitive rollers 9a to 9c and an opposed transfer roller 8 and also made movable rotationally in the direction of an arrow A. A photosensitive material cleaner 4, a discharging unit 5, a charging unit 2, a light exposure unit 6 and an image developer 3 are arranged in this order along the direction of a rotational movement of the photosensitive belt 1, and further toner 3a is contained inside of the image developer 3. In addition, a print sheet 7 is supported by a transfer plate 10 and transported in the direction C perpendicular to the rotational direction A of the photosensitive belt 1 by a print sheet transporting roller 11 as shown in FIG. 10.
An explanation will be made on how a prior art image forming device of quadrature transfer system as structured above operates. Upon receiving directions for an image forming operation from a controller of the image forming device such as a CPU and the like, a photosensitive roller driving means such as a motor and the like make the photosensitive rollers 9a to 9c rotate, thereby starting the rotation of the photosensitive belt 1 in the direction of the arrow A. First, the photosensitive belt 1 has the surface thereof charged by the charging unit 2 and then an electrostatic latent image is formed on the charged surface by laser light 6a irradiated from the light exposure unit 6 according to the content of an image to be formed.
When the area of the photosensitive belt 1 where the electrostatic latent image has been formed arrives at the position of the image developer 3, an image development roller 3b installed in the image developer 3 is rotated by an image development roller driving means such as a motor and the like and at the same time brought into contact with the photosensitive belt 1. Accordingly, while the photosensitive belt 1 is sandwiched and moved between the image development roller 3b and the photosensitive roller 9b, the electrostatic latent image is developed by the toner 3a attached to the surface of the image development roller 3b and a toner image 3c is formed on the photosensitive belt 1.
After the toner image 3c corresponding to a single sheet of the print sheet in size has been formed on the photosensitive belt 1 in the foregoing step of operation, the toner image 3c is transferred from the photosensitive belt 1 to the print sheet 7.
Before a transfer of the toner image 3c takes place, the rotati
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Hakukawa Kazuo
Hara Yukinori
Kizu Shinichi
Matsuzoe Hisanobu
Migita Kouji
Chen Sophia S.
Matsushita Electric - Industrial Co., Ltd.
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