KR19980051634A - Image forming apparatus of electrophotographic processor - Google Patents

Abstract

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

The present invention relates to an image forming apparatus of an electrophotographic processor capable of preventing contamination of a transfer roller by tubing or coating a surface of a transfer roller for transferring a toner image formed on the surface of a photosensitive drum onto a recording paper. It is about.

I. The technical problem that the invention is trying to solve.

The present invention can improve the transfer efficiency of the transfer roller.

All. Summary of the Solution of the Invention.

The present invention provides a transfer roller on a recording paper, a toner image formed on the surface of the photosensitive drum, a foam sponge having a constant elastic force to apply a constant nip and uniform pressing force with the photosensitive drum surface, and to prevent contamination and transfer of the transfer roller surface. It consists of a tube tubing in the outermost layer of the foam sponge to improve the function.

la. Important use of the invention.

An image forming apparatus of an electrophotographic processor.

Description

An image forming apparatus of an electrophotographic processor.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus of an electrophotographic processor such as a laser beam printer, a copier, a general paper facsimile machine, a multifunction machine, and more particularly, to tubing a surface of a transfer roller for transferring a toner image formed on a surface of a photosensitive drum onto a recording paper. The present invention relates to an image forming apparatus of an electrophotographic processor capable of preventing contamination of a transfer roller by coating or coating.

A general printing process will be described with reference to FIG. 1 of an image forming apparatus of a conventionally used electrophotographic processor.

When the toner 42 is supplied to the toner loading portion, the toner 42 is agitated by the stirrer 40 to generate static electricity by friction and thus has a constant charge. Thereafter, the stirred toner 42 is conveyed to the supply roller 44 side by the rotation of the stirrer 40. Thereafter, the toner 42 is supplied to the developing roller 36 side by the rotation of the feed roller 44, and the toner 42 formed on the surface of the developing roller 36 is fixed by the doctor-blade 38. It is regulated uniformly in height.

Thereafter, the surface of the photosensitive drum 30 is electrically uniformly charged to the negative polarity by the electrical action of the charging roller 32, and the portion charged by the rotation of the photosensitive drum 30 is exposed to the exposed portion 34. Is exposed to receive an electrical signal for forming an image. At this time, the portion that receives light in the initial charged state forms an electrostatic latent image. Thereafter, the electrostatic latent image formed on the surface of the photosensitive drum 30 is developed into a toner image while passing through the developing roller 36 to become a visible image.

Thereafter, the recording paper 46 mounted in the cassette (not shown) is fed to the transfer roller 10 side by a pickup roller, and then the recording paper 46 is subjected to the photosensitive drum 30 by the high pressure action of the transfer roller 10. ) The toner image on the surface is transferred. Then, on the recording paper 46, an image is fixed by heat and pressure while passing between the heating roller and the compression roller of the fixing unit (not shown), which is transferred to the pedestal side, whereby desired printing is performed.

However, the transfer roller which transfers the toner image formed on the surface of the photosensitive drum onto the recording paper in the process of performing the printing operation with the above configuration has a plurality of cells 14a as shown in Figs. It is composed of a foam sponge 14 formed of). Therefore, the transfer roller 10 causes the toner 42 to enter the cell 14a of the foam sponge 14, regardless of whether it is buried on the surface of the photosensitive drum 30 during the printing operation. Thereafter, a large amount of toner 42 is accumulated in the cells 14a of the foam sponge 14 due to the continuous printing operation.

That is, as shown in FIG. 5, when the toner 42 enters the cell 14a of the foam sponge 14 of the transfer roller, F = Q when an electric field is applied to clean the surface of the transfer roller 10. The force of E = Q.V / D acts to move toward the photosensitive drum 30. The toner 42 into the cell 14a is far from the photosensitive drum 30. Since the toner 42 is lost, it remains on the surface of the transfer roller 10 without being cleaned. Due to this, the surface of the transfer roller 10 is contaminated, which contaminates the back surface of the recording paper 46 during the next printing operation, and also causes a non-uniform resistance change to prevent a uniform electric field, thereby causing a transfer failure phenomenon. Problem occurred.

An object of the present invention to solve the above problems is to provide a transfer roller that can improve the transfer efficiency by tubing (tubing) or coating (coating) the surface of the transfer roller.

Another object of the present invention is to provide an image forming apparatus of an electrophotographic processor capable of preventing contamination of the surface of the transfer roller.

It is still another object of the present invention to provide an image forming apparatus of an electrophotographic processor that can prevent the phenomenon of toner on the back side of the recording paper when performing the printing process.

In order to achieve the above object, the present invention provides a photosensitive drum which rotates at a constant circumferential speed, a charging roller for electrically charging an electric charge layer uniformly on the surface of the photosensitive drum, and an exposure unit for forming an electrostatic latent image on the photosensitive drum surface. And a developing roller for developing the toner on the electrostatic latent image formed on the surface of the photosensitive drum, and a transfer roller for transferring the toner image formed on the surface of the photosensitive drum onto a recording paper. The transfer roller has a tubing treatment on the outermost layer of the foam sponge to have a uniform elastic force to apply a constant nip and uniform pressing force to the surface of the photosensitive drum, and to prevent contamination of the transfer roller surface and to improve the transfer function. It consists of a tube.

1 is a schematic diagram showing a configuration of an image forming apparatus of an electrophotographic processor commonly used.

Figure 2 is a perspective view showing the configuration of the transfer roller in the image forming apparatus of the electrophotographic processor according to an embodiment of the prior art.

Figure 3 is a schematic diagram showing an operating state (process) between the transfer roller and the photosensitive drum according to an embodiment of the prior art.

Figure 4 is a perspective view showing the configuration of the transfer roller in the image forming apparatus of the electrophotographic processor according to an embodiment of the present invention.

Figure 5 is a schematic diagram showing the operating state (process) between the transfer roller and the photosensitive drum according to an embodiment of the present invention.

Explanation of symbols for the main parts of the drawings

10: transfer roller 12: tube

14: foamed sponge 14a: cell

16: shaft 30: photosensitive drum

32: charging roller 34: exposed portion

36: developing roller 42: toner

46: recording paper

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are used for the same components, even if displayed 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 gist of the present invention, the detailed description thereof will be omitted.

Figure 4 is a perspective view showing the configuration of the transfer roller in the image forming apparatus of the electrophotographic processor according to an embodiment of the present invention. Figure 5 is a schematic diagram showing an operating state (process) between the transfer roller and the photosensitive drum according to an embodiment of the present invention.

As shown in Fig. 4, the inner surface of the transfer roller 10 for transferring the toner image formed on the surface of the photosensitive drum 30 onto the recording paper 46 has a nip constant with the surface of the photosensitive drum 30. A foam sponge 14 having a constant elastic force is installed along the circumferential surface of the shaft 16 in order to form a mold and apply a uniform pressing force. In this case, the foam sponge 14 is formed with a plurality of cells (14a), and the foam sponge 14 has a hardness of 10 degrees to 50 degrees and the resistance is cm to Has cm.

In addition, the outer surface of the foam sponge 14 prevents the surface of the transfer roller 10 from being contaminated by the toner 42 and at the same time a uniform voltage is applied to improve the transfer function. A tubing tube 12 is installed. At this time, the tube 12 forms a uniform roughness as a whole to press the surface of the photosensitive drum 30 at a constant pressure and the resistance is cm to has cm In addition, the outermost layer of the foam sponge 14 of the transfer roller can be coated (coating), without tubing treatment.

According to the above configuration, since the transfer roller is in full contact with the surface of the photosensitive drum 30 as shown in FIG. 5, the distance d between the photosensitive drum 30 and the transfer roller 10 d. ) Is near zero. As a result, when an electric field is applied to clean the surface of the transfer roller 10, a force of F = Q.E = Q.V / D is applied to the toner 42 so as to completely move toward the photosensitive drum 30. Will move. Then, the surface of the photosensitive drum 30 is cleaned by the operation of a vacuum cleaner and a latent image removal lamp (not shown).

As described above, the image forming apparatus of the electrophotographic processor according to the embodiment of the present invention can prevent contamination of the transfer roller by toner by tubing or coating the surface of the transfer roller with a tube. In addition, toner may be prevented from being contaminated by the toner on the back of the recording paper during printing, and the resistance of the tube of the transfer roller is made larger than that of the foam sponge so that most of the voltage applied to the transfer roller is applied to the surface layer. It has the effect that it can bring about the effect that the transfer function of the transfer roller in accordance with the environment changes stably.

Claims (5)

A photosensitive drum rotating at a constant circumferential speed, a charging roller for electrically charging the electric charge layer uniformly on the surface of the photosensitive drum, an exposure portion for forming an electrostatic latent image on the photosensitive drum surface, and an electrostatic latent image formed on the photosensitive drum surface An image forming apparatus of an electrophotographic processor comprising: a developing roller for developing a toner; and a transfer roller for transferring a toner image formed on the surface of the photosensitive drum onto a recording paper; The transfer roller 10 has a foam sponge 14 having a constant elastic force to apply a constant nip and a uniform pressing force with the surface of the photosensitive drum 30, and to prevent contamination and transfer of the transfer roller 10 surface An image forming apparatus of an electrophotographic processor, characterized in that it comprises a tube (12) tubing on the outermost layer of the foam sponge (14) for improvement. The method of claim 1, wherein the foam sponge 14 has a hardness of 10 to 50 degrees, the resistance is cm to An image forming apparatus of an electrophotographic processor, characterized in that cm. An image forming apparatus of an electrophotographic processor according to claim 1, wherein the surface of the tube (12) forms an entirely uniform illuminance to press the surface of the photosensitive drum (30) at a constant pressure. 4. The tube (12) according to claim 1 or 3, wherein the tube (12) has a resistance cm to An image forming apparatus of an electrophotographic processor, characterized in that cm. A photosensitive drum rotating at a constant circumferential speed, a charging roller for electrically charging the electric charge layer uniformly on the surface of the photosensitive drum, an exposure portion for forming an electrostatic latent image on the photosensitive drum surface, and an electrostatic latent image formed on the photosensitive drum surface An image forming apparatus of an electrophotographic processor comprising: a developing roller for developing a toner; and a transfer roller made of foam sponge for transferring a toner image formed on the surface of the photosensitive drum onto a recording sheet; The outermost layer of the foam sponge (14) of the transfer roller (10) is an image forming apparatus of the electrophotographic processor, characterized in that the coating treatment to improve the contamination prevention and transfer function of the surface of the transfer roller (10).