KR100297768B1 - Developing device of wet electrophotographic type printer - Google Patents

Abstract

PURPOSE: A developing device of a wet electrophotographic type printer is provided to restrict wrap around of developing solution at a side of a squeezing roller, thereby eliminating cause of surface pollution of photosensitive medium. CONSTITUTION: A developing device of the wet electrophotographic type printer includes a developing roller(10), a squeezing roller(12), a pair of free pulleys(16) and a pair of squeezing belts(14). The developing roller is rotatably mounted in a developing tank(8) for developing solution at a latent electrostatic image area of a photosensitive medium. The squeezing roller is rotatably mounted in the developing tank and compresses the photosensitive medium to squeeze developing solution stained on the photosensitive medium. The free pulleys are mounted on a rotating shaft of the developing roller and rotated freely. The squeezing belts are contacted with both sides of the squeezing roller and the photosensitive medium and mounted between the rotating shaft of the squeezing roller and the free pulleys to be rotated to the photosensitive medium.

Description

Developing apparatus for wet electrophotographic printing press

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wet electrophotographic printer, and more particularly, to a developing device for a wet electrophotographic printer in which the structure thereof is improved to prevent the developer from being wrapped around the squeegee roller.

BACKGROUND ART In general, a wet electrophotographic printing machine is a device for printing a desired image by developing an electrostatic latent image formed on a photosensitive medium such as a photosensitive belt with a developer having a predetermined color and transferring it to a paper. Such a wet electrophotographic printing machine includes a developing device for supplying and developing a developer to a photosensitive medium.

The developing apparatus forms an electrostatic latent image on the photosensitive medium, and then removes the carrier of the liquid phase from the electrostatic latent image, and the primary squeegee roller to remove the carrier and developer passing through both ends of the primary squeegee roller. And a secondary squeegee roller that rotates in the opposite direction to remove the developer that is wrapped around.

Another method of preventing the wrap-around phenomenon is to blow the air from both ends of the primary squeegee roller toward the center before the electrostatic latent image region passes through the primary squeegee roller to prevent the developer from passing over.

However, the method using the secondary squeegee roller can damage the surface of the photosensitive medium because the contact rotation in the opposite direction to the traveling direction of the photosensitive medium. In addition, there is a possibility of malfunction due to contamination of the tip of the nozzle because the method of using air must continuously blow air of a constant pressure.

In addition, wraparound occurring at both ends of the primary squeegee roller is a cause of cross contamination of the developer, especially during color printing.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object thereof is to provide a developing apparatus of a wet electrophotographic printing machine having an improved structure to prevent the developer from being wrapped around the squeegee roller.

1 is a plan view schematically showing the main part of a developing apparatus of a wet electrophotographic printer according to an embodiment of the present invention;

2 is an exploded perspective view of a main part of the developing apparatus shown in FIG. 1;

3 is a side view of the squeegee belt of FIG. 2 in contact with the photosensitive medium;

<Description of the symbols for the main parts of the drawings>

6 ... photosensitive belt 8 ...

10 ... developing roller 12 ... squeegee roller

14 ... squeegee belt 16 ... free pulley

18.Restricted pulley

A developing apparatus for a wet electrophotographic printing press according to the present invention for achieving the above object, the developing roller rotatably installed in the developing tank, for developing the developer in the electrostatic latent image area of the photosensitive medium; And a squeegee roller rotatably installed in the developing tank and squeezing the photosensitive medium to squeeze the developer on the photosensitive medium. A pair of free pulleys installed on the rotating shaft of the developing roller and freely rotating thereto; And a pair of squeegee belts, which are in contact with both side surfaces of the squeegee roller and the photosensitive belt, respectively, and are installed between the rotating shaft of the squeegee roller and the free pulley so as to follow the photosensitive medium.

In addition, the apparatus further includes a pair of restraint pulleys installed on the rotating shaft of the squeegee roller so that the squeegee belt can be wound.

Here, the free pulley is formed such that the radius from the center of rotation of the developing roller of the squeegee belt wound on the outside thereof is larger than the radius of the developing roller by a developing gap, so that the gap between the developing roller and the photosensitive medium is The development gap is maintained, and the surface of the squeegee belt opposite to the photosensitive medium contacts the photosensitive medium.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 and 2 are a plan view and an exploded perspective view schematically showing the main part of the developing apparatus of the wet electrophotographic printer according to the present invention.

As shown, the apparatus includes a developing roller 10 for developing the developing solution 4 injected from the spray nozzle 2 in the electrostatic latent image region 6a of the photosensitive belt 6, and the electrostatic latent image region 6a. And a pair of squeegee belts 14 which rotate in contact with both sides of the squeegee roller 12 and both lengthwise directions of the photosensitive belt 6 to remove excess developer developed in do.

The developing roller 10 is provided in the developing tank 8, and the developing roller 10 is provided with a pair of free pulleys 16 which can freely rotate on both sides thereof. In addition, the developing roller 10 is installed in the developing tank 8 so as to rotate while maintaining the photosensitive belt 6 and a predetermined distance (DG in FIG. 3 (hereinafter, referred to as "developing gap")). The developing solution 4 injected from the injection nozzle 2 is developed into the electrostatic latent image region 6a by a potential difference.

The squeegee roller 12 is installed in the developing tank 8 so as to be driven to rotate on the photosensitive belt 6, and forms a toner in the developing solution attached to the electrostatic latent image region 6a to form a developing film (film) and removes liquid carriers other than toner. do. In addition, the squeegee roller 12 includes a pair of restraint pulleys 18 integrally formed on both sides thereof.

The squeegee belt 14 has a free pulley 16 and a restraining pulley 18 so that the outer diameter thereof is the same as the outer diameter of the squeegee roller 12 and is wound larger than the outer diameter of the developing roller 10 by the developing gap DG. Is installed on. To this end, the pulleys 16 and 18 have grooves formed on the outer circumferential surface thereof, and the squeegee belt 14 has a triangular cross section so as to be wound around the grooves.

On the other hand, the tangent formed by the squeegee roller 12 and the photosensitive belt 6 and the tangent formed by the squeegee belt 14 and the photosensitive belt 6 have a "c" shape. Therefore, the wraparound phenomenon in which the developer passes over both sides of the squeegee roller 12 by capillary action is prevented.

The operation of the developing apparatus according to the present embodiment having the above configuration will be described below.

The developing solution 4 injected by the injection nozzle 2 is first developed into the electrostatic latent image region 6a by a potential difference at the developing gap DG. The electrostatic latent image region 6a contains a large amount of carriers, which are substantially removed by the squeegee roller 12 which presses the surface of the photosensitive belt 6 at a constant pressure. The toner particles are also changed into a film as described above.

At this time, some of the excess carriers removed by the squeegee roller 12 are moved out of the electrostatic latent image region 6a along the gap between the squeegee roller 12 and the photosensitive belt 6 in the axial direction of the squeegee roller 12. Go on. The developing solution B is blocked by the squeegee belt 14 installed to be in linear contact with both sides of the squeegee roller 12 and the photosensitive belt 6 in a "c" shape, and fall to the bottom of the developing tank 8.

As described above, the developing apparatus of the wet electrophotographic printer according to the present invention prevents wraparound of the developer by a squeegee belt which rotates in contact with the squeegee roller and the photosensitive belt. Therefore, cross contamination between the developer is prevented by eliminating the cause of surface contamination of the photosensitive medium.

In addition, since the secondary squeegee roller is not separately installed to prevent wraparound, the number of parts can be reduced and the size of the developing apparatus can be reduced.

Claims (3)

A developing roller rotatably installed in the developing tank for developing the developer in the electrostatic latent image area of the photosensitive medium; A squeegee roller rotatably installed in the developing tank and squeezing the photosensitive medium to squeeze the developer solution on the photosensitive medium; A pair of free pulleys installed on the rotating shaft of the developing roller and freely rotating thereto; And A pair of squeegee belts provided between the both sides of the squeegee roller and the photosensitive belt, respectively, between the rotating shaft of the squeegee roller and the free pulley so as to be driven on the photosensitive medium to suppress the wraparound of the developer. Developing apparatus for a wet electrophotographic printing machine, characterized in that. The developing apparatus according to claim 1, further comprising a pair of restraint pulleys installed on a rotation shaft of the squeegee roller so that the squeegee belt can be wound. The method of claim 1 or 2, wherein the free release, The radius from the center of rotation of the developing roller of the squeegee belt wound on the outside thereof is formed to be larger than the radius of the developing roller by a developing gap, And the developing gap is maintained between the developing roller and the photosensitive medium, and the surface of the squeegee belt opposite to the photosensitive medium is brought into contact with the photosensitive medium.