JPH0244069B2 - GENZOSOCHINOSHIBORIROORUKIKO - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a developing device for a photographic photoreceptor, and more particularly, the present invention relates to a developing device for a photographic photoreceptor, and more specifically, a developing device for developing an electrophotographic photoreceptor having a photoconductive photosensitive layer using a developer (so-called wet toner). The present invention relates to a squeeze roll mechanism of a developing device used for.

In recent years, lithographic printing plates made of electrophotographic photoreceptors have become
Because of its high sensitivity, there is no need for negative film, which was conventionally required during plate-making, and in particular, it is possible to directly photograph and expose the lithographic printing plate from the reflective original, which can shorten plate-making time and reduce plate-making costs. It is being put into practical use because it is profitable.

Such a lithographic printing plate is made of a mechanically strong conductive support, such as a metal plate such as an aluminum plate, a zinc plate, or an iron plate, or a synthetic resin film on which a metal is vapor-deposited, or a metal foil is laminated to the support. , a lithographic printing plate coated with a photoconductive photosensitive layer in which a photoconductive organic pigment is dispersed or dissolved in a phenolic resin, for example, copper phthalocyanine is dispersed in a novolac resin, on a support such as a so-called composite. The electrostatic latent image is formed on the photosensitive layer by charging and exposing it to light using an electrophotographic method, and a toner image is obtained from this in a developing process. The present invention relates to a squeeze roll mechanism of a developing device that is effective for use in such a developing process.

Conventionally, the support of an electrophotographic photoreceptor is almost always paper, which is flexible and has a relatively thin thickness. The lower side is composed of a rubber roll and the upper side is a metal roll, and even when the developer is squeezed out, there is almost no possibility that the developer will be brought into the next process due to poor squeezing or that the toner developing area will be disturbed. however,
Among planographic printing plates, especially when a photoreceptor whose support is a metal plate or a metal-synthetic resin composite is developed and squeezed using a conventional developing device, the developer cannot be completely squeezed out. In addition, in order to enhance the squeezing effect, the squeezing roll pair was constructed of upper and lower rubber rolls to carry out development and squeezing, but it was still not possible to squeeze out the developer completely. This causes problems such as carrying the developer into the next process, wasting the developer, and disturbing the toner developing area. The reason for this is that the lithographic printing plate is thick and hard, for example, about 200 μm or more, so the contact between the upper and lower sides of the lithographic printing plate is broken at both ends of the lithographic printing plate while it is passing through the squeezing roll, and the accumulation occurs in the gap. It turns out that this is because the dripping developer comes out of the aperture roll pair with the developing solution adhering to the photosensitive surface again. The present invention was completed as a result of intensive studies to solve the above problems.

The present invention eliminates disturbances in the developed area of a photosensitive layer, wastage of developer, and carry-over of developer to the next process due to poor aperture of a liquid developing device, and obtains a good aperture effect and a good developed image. It is an object of the present invention to provide a squeeze roll mechanism in a liquid developing device that can perform the following steps.

That is, according to the present invention, there is provided a liquid developing device having at least one pair of developer squeezing roll mechanisms,
The photoreceptor to be developed is located on the side where the photoreceptor to be developed comes out from the pair of squeeze rolls, and means is provided for blowing gas toward the respective gaps at both ends formed by the pair of squeeze rolls and the ends of the photoreceptor to be developed. A squeeze roll mechanism for a liquid developing device is provided.

Hereinafter, the present invention will be explained with reference to illustrated embodiments.

FIG. 1 is a schematic side view showing one embodiment of the present invention, and FIG. 2 is a partial top view of FIG. 1. A lithographic printing plate 1 having a photoconductive photosensitive layer provided on a support such as an aluminum plate is placed in a developing device according to the present invention with a pair of transport rolls 4, with its electrostatic latent image surface facing upward.
5 and is guided and conveyed into developing devices 6 and 7.
The developer 9 in the developer reservoir 10 is filled by the pump P from the developer supply pipe 8 into the developing section consisting of the upper developer plate 6 and the lower developer plate 7, so that the lithographic printing plate 1 is developed. Then, it leaves the squeezing roll pair 2 and 3 and is guided and conveyed to the next process. When passing between the upper squeeze roll 2 and the lower squeeze roll 3, a gap 11 as shown in FIG. 2 (a cross-sectional view of the roll pair taken along line A-A' in FIG. 1)
are formed on both sides of the planographic printing plate 1. The gaps 11, 11 are determined by the thickness of the photoreceptor and the aperture roll pair 2,
They are formed to have different sizes depending on the material of No. 3.

The planographic printing plate 1
The developer 9 is prevented from leaking out by blowing gas, which is force-fed by the blower 13, from the end of the nozzle 12 from the side where it exits from the squeezing roll pair 2, 3, and the lithographic printing plate 1 after development is The developer is completely squeezed out before being discharged.

A specific example of the shape of the tip of the nozzle 12 is shown in FIG. 4, but the present invention is not limited thereto, and may be circular, oval, square, or rectangular.

Note that if the tip of the nozzle 12 is sized so that the gas can be sprayed locally into the cavity 11, the efficiency of spraying will be better and uneven drying of the photoreceptor can be avoided, but even if the gas spreads to a certain extent, good. In addition, the amount of gas to be sprayed should be adjusted so that the developer is not significantly scattered on the opposite side of the squeezing roll pair 2 and 3.
A larger amount is desirable as long as it does not cause uneven drying of the photoreceptor, and this amount can be determined by a simple experiment. The gas may normally be air. The temperature of the gas to be blown is preferably about room temperature, but warm air may be used if necessary. Furthermore, there may be a plurality of squeeze roll pairs 2, 3.

Regarding examples of lithographic printing plates, for example,
A lithographic printing plate was prepared by providing an organic photoconductive layer (approximately 10 μm) on an aluminum plate with a thickness of 0.3 mm. After development, this lithographic printing plate can be made into a lithographic printing plate by etching away the non-image area where there is no toner with an alcohol or/and alkaline aqueous solution.

The lithographic printing plate 1 was charged using a developer apparatus shown in FIG. 1, in which the squeeze rolls 2 and 3 were a pair of squeeze rolls made of a rubber material, and after image exposure, liquid development was performed. When air was not blown from the tip of the nozzle 12 into the two gaps 11 by the blower 13, the photosensitive surface was significantly smudged by toner, but when air was blown, there was no toner smudge at all, resulting in extremely good sensitization. I was able to confirm that it was a surface.

Since the present invention has the above-described structure and function, there is no wastage of developer, no disturbance of the toner developing area due to poor squeezing of the developer, and no adverse effects on subsequent processes such as drying, fixing, rinsing, etc. This has a great practical effect.

[Brief explanation of the drawing]

1 is a schematic side view showing a specific example of a developing device equipped with a squeeze roll mechanism according to an embodiment of the present invention; FIG. 2 is an enlarged cross-sectional view of a pair of rolls taken along line A-A' in FIG. 1; FIG. 3 is a partial top view of FIG. 1, and FIG. 4 is a specific example of the nozzle tip shape. DESCRIPTION OF SYMBOLS 1...Photoreceptor, 2...Upper aperture roll, 3...Lower aperture roll, 4 and 5...Transportation roll pair, 6 and 7...
Developing plate, 8... Developer supply pipe, 9... Developer, 10...
Developer reservoir, 11... Gap, 12... Nozzle, 13...
Blower.

Claims (1)

[Claims] 1 A liquid developing device having at least one pair of developer squeezing roll mechanisms, wherein the photoreceptor to be developed is on the side coming out from the pair of squeezing rolls, and formed by the pair of squeezing rolls and the end of the photoreceptor to be developed. 1. A squeezing roll mechanism in a liquid developing device, characterized in that the squeezing roll mechanism is provided with a means for blowing gas toward a gap in which the gas is formed.