JPH0345244Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pair of developing rollers for an electrophotographic engraving machine, and more particularly to a pair of developing rollers for an electrophotographic engraving machine that can prevent the rollers from becoming dirty due to development processing.

For example, electrophotographic plate making materials used in so-called direct plate making are developed with a liquid developer containing toner after exposure.

The problem here is the staining of the developing roller pair due to the toner adhesion. This dirt is
It is transferred to the electrophotographic material and causes undesirable staining of the printed surface.

The present invention was made in view of the above circumstances, and its purpose is to solve the above-mentioned problems in the conventional developing roller pair for electrophotographic engraving machines.
An object of the present invention is to provide a developing roller pair for an electrophotographic engraving machine which is free from dirt.

The above-mentioned object of the present invention is to provide a developing roller pair for an electrophotographic plate-making machine that processes a plate-making material having an electrophotographic photosensitive layer on one side using a liquid developer, in which the roller pair contacts the electrophotographic photosensitive layer of the plate-making material. The roller on the side facing the electrophotographic photosensitive layer and the roller opposite thereto are made of materials having different orders in the charging series, and the roller on the side facing the electrophotographic photosensitive layer is made of materials having the same toner particles contained in the liquid developer. This is achieved by a developing roller pair for an electrophotographic engraving machine, which is characterized in that it is configured to be polarized.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 is a side view of a developing roller pair (hereinafter simply referred to as "roller pair") for an electrophotographic engraving machine, showing an embodiment of the present invention. In this example, the electrophotographic plate material (hereinafter referred to as "plate material") is
It is assumed that the electrostatic image has a positive charge, and the electrostatic image is developed with a liquid developer containing a toner having a negative charge.

In FIG. 1, it is assumed that 1 is a plate material whose upper surface has an electrostatic image. Reference numeral 2 designates a stepped roller having a stepped portion 2A that contacts only both side edges of the plate material 1 and does not contact the central portion (image area), and 3 designates a lower roller having a uniform thickness throughout. The stepped portion 2A of the stepped roller 2 is formed to prevent damage to the image (electrostatic image, toner image) formed on the surface of the plate material 1.

The stepped roller 2 and the lower roller 3 are urged toward each other by a spring (not shown), and are connected to a drive source (not shown) to move the plate material 1 at a predetermined speed. It is configured so that it can be transported by

Furthermore, the stepped roller 2 is made of nitrile rubber, and the lower roller 3 is made of polyurethane rubber. As can be understood from the electrification series (frictional electrification series) shown in FIG. The lower roller 3 has the property of being electrically charged.

Using the developing roller pair configured as described above, the plate material 1 is prepared using a liquid developer containing the following components.
When the development process was carried out continuously, there was no occurrence of stains as had been seen in the past. Note that toner particles in the liquid developer containing the following components are known to be negatively charged.

[Developer component]

Carbon black Vinyl toluene/2EHMA/LMA Isopar G (trade name of "Etsuo Oil Co., Ltd.") In the above example, since a liquid developer containing negatively charged toner particles was used, the stepped roller 2 of the developing roller pair Although the stepped roller 2 is configured to be negatively charged, it goes without saying that if a liquid developer containing positively charged toner particles is used, it is necessary to configure the stepped roller 2 to be positively charged. stomach.

It should be noted that a large number of charging sequences other than those shown in FIG. 2 have been proposed, and some of them have different orders, so care must be taken. When configuring a pair of developing rollers, it is important to select the roller material with reference to the above-mentioned electrification series, and to conduct sufficient consideration in consideration of corrosion resistance to liquid developer, mechanical durability, etc. .

As described above, according to the present invention, in a developing roller pair for an electrophotographic plate-making machine that processes a plate-making material having an electrophotographic photosensitive layer on one side using a liquid developer, an electrophotographic image of the plate-making material of the roller pair is provided. The roller on the side that contacts the photosensitive layer and the roller that opposes it are made of materials having different orders in the charging series, and the roller on the side that faces the electrophotographic photosensitive layer is made of materials that are contained in the liquid developer. Since the rollers are configured to be charged to the same polarity as the toner particles, it is possible to realize a pair of rollers that completely prevents staining caused by toner adhesion.

[Brief explanation of drawings]

Figure 1 is a side view showing one embodiment of the present invention;
The figure shows an example of a charging sequence. 1: Plate material, 2: Stepped roller, 2A: Stepped portion,
3: Lower roller.

Claims (1)

[Claims for Utility Model Registration] (1) In a developing roller pair for an electrophotographic plate-making machine that processes a plate-making material having an electrophotographic photosensitive layer on one side using a liquid developer, an electrophotograph of the plate-making material of the roller pair is provided. The roller on the side that contacts the photosensitive layer and the roller that opposes it are made of materials having different orders in the charging series, and the roller on the side that faces the electrophotographic photosensitive layer is made of materials that are contained in the liquid developer. A developing roller pair for an electrophotographic engraving machine, characterized in that it is configured to be charged to the same polarity as toner particles. (2) The utility model according to claim 1, characterized in that the roller on the side of the plate-making material that contacts the electrophotographic photosensitive layer is a stepped roller that contacts only the side edges of the plate-making material. A pair of developing rollers for electrophotographic engraving machines.