KR19990000272A - Transfer device of color image forming apparatus - Google Patents

Abstract

end. The technical field to which the invention described in the claims belongs.

The present invention relates to a transfer apparatus of a color image forming apparatus.

I. The technical problem to be solved by the invention.

The present invention provides a transfer apparatus of a color image forming apparatus which realizes good transfer without reverse transcription and which prevents image eccentricity or color eccentricity to obtain a high quality image.

All. Summary of the Solution of the Invention.

The transfer drum of one embodiment according to the technical concept of the present invention is composed of a hair elastic layer, a conductor layer, and a dielectric layer sequentially on the outer circumferential surface of the hollow drum.

la. Important uses of the invention

A transfer apparatus of a color image forming apparatus.

Description

Transfer device of color image forming apparatus

The present invention relates to a transfer apparatus of a color image forming apparatus in an electrophotographic processor using an electrophotographic or electrostatic lock method.

1 is a perspective view illustrating a transfer drum of a color image forming apparatus according to an exemplary embodiment. Referring to the drawings,

The transfer drum 100 has a cylindrical flange (101, 102) and the connecting member 103 for connecting both flanges (101, 102) is integrally formed, the peripheral opening 104 is formed. The opening 104 of the transfer drum is provided with a transfer sheet 106 (transfer film) made of a dielectric layer such as PVDF. The transfer sheet 106 is shown by a dashed line. In addition, a corona charger 107 is provided inside the transfer drum, and a transfer operation is performed by generating a corona discharge from the inside of the transfer sheet 106 by the charger 107.

The transfer drum 100 is provided with a gear 102a on the flange 102 of one side, and is driven in engagement with a not shown gear formed on the photosensitive drum. In addition, a hard rubber layer of irregularities is provided on the outer peripheral surface of the flange (not shown), and the rubber layer is in contact with the outer peripheral surface of the photosensitive drum to establish a positional relationship between the transfer drum and the photosensitive member.

In this case, a gap corresponding to the thickness of the rubber layer corresponding to the transfer material (recording paper or transfer film) between the transfer drum and the photosensitive drum is generated. In particular, during transfer, the member is pushed at a constant pressure by a member pushing in the transfer drum such that the transfer material and the photosensitive drum are in constant pressure contact.

However, in such a conventional transfer drum configuration, there is a problem in durability because there is almost no portion fixing the transfer drum around the transfer drum.

On the other hand, there is a rubber roller transfer device which forms a foamed elastic layer and a dielectric layer on a hollow drum as a structure of a transfer device conventionally known.

The rubber roller transfer device is configured to push a transfer drum having a foam elastic layer to set a proper contact force between the transfer material and the photosensitive drum by a deformation of the foam elastic layer of the transfer drum at a predetermined pressure. Even in the transfer apparatus having such a foamed elastic layer, since the proper pressure is maintained by the inner foamed elastic layer of the dielectric layer, the transfer efficiency and image quality are greatly influenced by the characteristics of the foamed elastic layer. In particular, it is difficult to maintain the proper hardness of the foamed elastomer, and problems such as elasticity change according to environmental conditions occur in terms of durability and reliability. In addition, since the roller transfer device does not require a corona charger, there is a marit from the viewpoint of little ozone generation, but the following general problems occur.

First, when the contact pressure with the photosensitive drum is large, a reverse transfer phenomenon (untransferred region) occurs in which the inside of the toner image is not transferred.

Secondly, if the compression amount of the transfer drum is too large, the actual transfer image deviates from the position where the image should be transferred to the transfer material. This is regarded as the cause of color eccentricity in the color image forming apparatus.

The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a transfer apparatus of a color image forming apparatus capable of performing good transfer without reverse transcription.

Another object of the present invention is to provide a transfer apparatus of a color image forming apparatus, in which image eccentricity or color eccentricity can be prevented to obtain a high quality image.

In order to achieve the above objects, the transfer drum of one embodiment according to the technical idea of the present invention is composed of a hair elastic layer, a conductor layer and a dielectric layer sequentially on the outer peripheral surface of the hollow drum.

1 is a perspective view showing the configuration of a transfer drum of a color image forming apparatus according to a conventional embodiment

2 is a block diagram showing a color image forming apparatus according to an embodiment of the present invention

3 is a cross-sectional view showing the configuration of a transfer apparatus according to an embodiment of the present invention.

Figure 4 is a plan view showing the installation state of the transfer drum and the photosensitive drum according to an embodiment of the present invention

* Explanation of symbols on the main parts of the drawings *

1: photosensitive drum 10Y, 10M, 10C, 10Bk: developing

150: transfer roller 151a: conductive hair elastic layer

Hereinafter, with reference to the accompanying drawings will be described in detail the most preferred embodiment of the present invention. First, in describing each of the drawings, only the same components have the same reference numerals as much as possible even if shown on different drawings. In describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

2 is a block diagram schematically illustrating a color image forming apparatus according to an exemplary embodiment of the present invention. Referring to the drawings,

The color laser beam printer includes a photosensitive drum 1 rotating in an arrow direction (clockwise), and includes a primary charger 4, a semiconductor laser 5, and a scanner motor 6 in the outer circumferential direction of the photosensitive drum 1. ), The exposure means is arranged from the mirror 7, the lens 8, and the mirror 9 which are rotated by the scanner motor 6. The laser scanning unit (LSU) emits light L emitted from the semiconductor laser 5 to which the video signal of the controller is input to the mirror 7, and then exposes the lens 8 and the mirror 9. Passed to the photosensitive drum (1), and forms a latent image on the photosensitive drum (1).

In the outer circumferential direction of the photosensitive drum 1, a developing device for making a latent image on the photosensitive drum into a toner image is arranged. That is, a plurality of developing devices each filled with toners of yellow (10Y: YELLOW), magenta (10M: MAGENTA), cyan (10C: CYAN), and black (10Bk: BLACK) are sequentially installed.

Usually, a transfer recording paper called a transfer material is stacked in the paper feed cassette 12. When the pickup roller is rotated, the topmost sheet of the plurality of sheets is converted into a transfer force by friction with the pickup roller, and the sheet is cut. Are sequentially transferred to the transfer device. That is, it is conveyed in the direction of the arrow.

The transfer paper supplied to the transfer device passes the transfer positions of the photosensitive drum 1 and the transfer drum 150 to transfer the toner image on the photosensitive drum 1. In the case of multiple transfer of a plurality of color images onto the transfer paper, a toner image is formed for each color of the photosensitive drum, the toner images of the photosensitive drum are transferred to the transfer paper one color, and the transfer operation is repeated as many times as necessary.

The toner on the photosensitive drum 1 remaining after being transferred to the transfer paper transferred to the transfer apparatus is removed by the cleaner 16, and the toner image of the transfer paper separated from the transfer apparatus is fixed to the fixing unit (heating roller 17 and the pressing roller 18). It is settled in the) and is discharged toward the discharge tray 19 by the discharge roller.

In a preferred embodiment of the present invention, the photosensitive drum 1, the charger 4, the developer 10, and the cleaner 16 are integral cartridges, which can be detached from the image forming apparatus.

3 is a cross-sectional view showing the configuration of a transfer apparatus according to an embodiment of the present invention. The transfer roller will be described with reference to the drawings.

As shown in FIG. 3, the transfer apparatus includes a hollow drum 151 made of aluminum or a conductive plastic, and flanges 152 and 153 formed of an insulator at both ends of the hollow drum 151, and rotates the rotating shaft of the transfer drum 150. The fixed shaft 154 passed through is formed, and the fixed shaft rotates by the bearings 155 and 156 formed on both flanges 152 and 153 in the transfer drum 150. In addition, one flange 152 is formed with a gear 157, the gear 157 meshes with the flange gear of the electrosensitive drum driven from the drive source, and rotates the transfer drum. The transfer drum 150 may also be provided with a gripper for discharging the transfer paper.

The transfer drum 150 is composed of a conductive hair elastic layer 151a, a conductor layer 151b, and a dielectric layer 151c on the outer circumferential surface of the hollow drum 151.

The dielectric layer 151c has a sheet shape, and is made of a copolymer such as polyfluoride vinylidene or polyethylene terephthalate, and the conductor layer 151b is implemented by depositing alumina or carbon powder on the dielectric sheet.

The conductive hair elastic layer 151a contains a conductive material capable of conducting electricity in soft rayon or soft nylon. The length of the hair is most preferably 10 mm or less, and the elastic effect is also required, so that at least 3 mm is required. The thickness is most appropriate.

The soft rayon conductive hair elastic layer requires a certain amount of load in the initial deformation region due to the characteristics of the hair, but the deformation amount according to the load is almost constant in the region after the initial load. In the present invention, since the portion having little change in load is used, the elastic load by the conductive hair elastic layer is constant within the nip width of 3 mm, so that good transfer without reverse transfer on the toner can be achieved regardless of the external force.

4 is a view showing a gap between the photosensitive drum and the transfer drum according to an embodiment of the present invention. Referring to the drawings,

A rigid rubber layer projection 160 is mounted on the flange of the transfer drum as shown in the related art with respect to FIG. 2, minus the surface of the transfer drum 150, so that the rubber layer contacts the photosensitive drum. By installing a spring 162 having a transfer drum 150 is designed to be in close contact with the photosensitive drum (1).

In this way, even when the support shaft of the transfer device for maintaining the contact force is pressurized with an elastic force, by forming the projection of the transfer drum, it is possible to prevent the contact pressure between the drive side and the non-drive side of the transfer device.

In addition, the hair elastic layer 151a has an advantage of preventing image eccentricity and color eccentricity that are easily generated in an elastic layer by a sponge or the like. This is because the elastic layer by the sponge is connected to the elastic layer itself, the hair elastic layer is provided with each of the hair elasticity can prevent the image eccentricity, color eccentricity caused by the elastic layer sliding phenomenon.

Therefore, in one embodiment of the present invention, the conductive hair elastic layer of the transfer drum has a compression amount of 0.5 to 2 mm at the transfer position, and in this range, the contact pressure between the photosensitive member and the transfer drum is constant because the contact pressure is 35 g / cm 2 or less. It is possible to realize the transcription without reverse transcription.

On the other hand, in the detailed description of the present invention has been described with respect to specific embodiments, it will be apparent to those skilled in the art that various modifications are possible without departing from the scope of the present invention.

As described above, the transfer apparatus of the present invention can obtain a high quality image without reverse transcription, image eccentricity, or color eccentricity.

Claims (4)

A color image forming apparatus comprising a photosensitive member, image forming means for forming a toner image on the photosensitive member, and a transfer drum for transferring the toner image of the photosensitive member to a transfer material at a transfer position, And the transfer drum comprises a hair elastic layer, a conductor layer, and a dielectric layer sequentially on the outer circumferential surface of the hollow drum. The transfer apparatus of claim 1, wherein the hair elastic layer is a conductive hair elastic layer. 3. The transfer apparatus according to claim 2, wherein the conductive hair elastic layer is conductive soft rayon or conductive soft nylon or carbon fiber. The transfer apparatus of claim 1, wherein the hair elastic layer has a suitable length of less than 10 mm and most preferably about 3 mm.