JPS593449A - Engraving method of electrophotoengraving material - Google Patents

Abstract

PURPOSE:To prevent the entry of the combustible solvent for toner development into an electrostatic charging part without any flaw, unevenness and contamination on a machine plate even after long-term use, by flowing air having prescribed temp. and humidity to at least the electrostatic charging part and/or exposing part of an engraver. CONSTITUTION:A cooling mechanism 22, a heating mechanism 23 and a blower fan 24 are provided to a temp./humidity control part 1, and the air controlled to prescribed conditions is fed to a presetting part 2 and an electrostatic charging part 3 to control the temp. and/or humidity thereof. The air flows out through the slit 19 in a delivery port for engraving material so that the temp. and humidity in an exposing part 4 can be substantially controlled by said air. A developing part 5 is substantially isolated by the control of the electrostatic charging part, whereby the intrusion of the evaporated solvent thereof into a corona charging part 2 and the explosion thereof are prevented. The device is so arranged that the air flows successively through the presetting part, the part 3, the exposing part, the developing part, etc., and it is equally well to arrange the same so as to feed the air separately to the respective parts.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides excellent image tone reproducibility using electrophotography,
It relates to a plate-making method for continuously producing printing plates with stable printing durability with good reproducibility and in a stable manner, especially when using a support having a layer of polyolefin or metal foil laminated on at least one surface of the base paper. The present invention relates to a plate-making method for obtaining a printing plate from an electrophotographic plate-making material having a photoconductive layer thereon.

Methods for preparing lithographic printing plates by electrophotography are known, and generally involve uniformly charging a photoconductive layer from an electrophotographic material, imagewise exposing it, and then wet or dry development. A printing plate is produced by forming a toner image, then fixing it or converting it into a liposensitized image, and then making the non-image area where there is no toner image hydrophilic, such as by treating with a desensitizing fluid (etching fluid). . (For example, patent application No. 56-12332
No. 5.

(See Japanese Patent Application No. 156829/1982).

Electrophotographic printing materials using a paper support are known, but their printing durability is approximately 3,000 sheets at most, and the reason for this is water penetration into the support. In addition, the image quality is stable, taking the reproducibility of halftone dots as an example.
00 lines/inch, and its causes include non-uniformity of the surface of the photoconductive layer, charging property, and conductivity.

Various efforts have been made to solve this problem. For example, JP-A-50-138904, JP-A-55-1
It is known that printing durability and image quality can be improved by coating the surface of base paper with a water-resistant polymer compound or resin, as described in Japanese Patent Application Laid-open No. 05580 and Japanese Patent Application Laid-Open No. 14804-1985. Also, Japanese Patent Application No. 56-125525 or Japanese Patent Application No. 5
As described in No. 6-156829, an electrophotographic printing material having a support made of a base paper laminated with polyolefin or metal foil on at least one side has also been proposed. The present inventors used an electrophotographic printing material as a support by coating a base paper with a water-resistant polymer compound or resin to prevent almost all water from penetrating, or by laminating polyolefin or metal foil as described above. I tried making a plate using a plate that was almost completely water-resistant and had a smooth surface, but the results were not satisfactory. Even if the optimum conditions for plate making are set, the sensitivity, printing durability, image tone reproducibility, and occurrence of stains will vary depending on the season or during the initial and late stages of operation, and as a result, the sharpness rate of the plate making process will change. It has been found that defects occur that result in a high defective rate (defect rate) and high plate-making costs.

The purpose of the present invention is to improve these deficiencies.

That is, the first object of the present invention is to provide a method for obtaining a printing plate that is stable, uniform, and has good image reproducibility even after long-term use without causing scratches, uneven force, or stains on the printing plate. be. The second object is to provide a plate-making method that allows printing plates with sufficient printing durability to be stably obtained regardless of the external environment, such as summer, winter, and the rainy season. The third purpose is to prevent the risk of a flammable solvent used for toner development getting mixed into the charging section and catching fire. Another object of the present invention is to provide a plate-making method that stably exhibits excellent properties using an electrophotographic material having a laminate layer of yN lyolefin or metal foil on at least one side of a paper-based support. We are busy providing a plate-making method with low back printing costs.

As a result of various studies, the present inventors have found that the above object can be achieved by the present invention as described below.

That is, the present invention provides a printing plate by sequentially sending an electrophotographic plate material having a photoconductive layer on a support from a presetting section of a plate making machine to a charging section, an exposing section, a toner developing section, and a fixing section. It is suitable for the plate making method to obtain 15C~40r
The plate-making process is carried out while flowing air controlled at a temperature of preferably 18r to 25r and a relative humidity of 60 to 60 degrees, preferably 40% to 50 degrees, to at least the charging section and/or the exposing section of the plate making machine. This is a plate-making method characterized by the following.

The present invention has a layer laminated with polyolefin or metal foil on at least one surface of a base paper as described in, for example, Japanese Patent Application No. 56-12!1325 and Japanese Patent Application No. 5<S-156829. However, it is particularly effective when a printing plate is obtained from an electrophotographic printing material having a support having a volume resistivity of about 100 or less.

The features of the present invention are as follows.

That is, for example, when manufacturing printing plates by electrophotography using an electrophotographic plate material as a base paper support as described above, extremely excellent results can be obtained under appropriate conditions of predetermined temperature and humidity. However, the problem is that it is highly dependent on conditions, and if it deviates from the predetermined conditions, it becomes difficult to maintain excellent performance. The first feature of the present invention is that when back printing is performed in row 5 using such an electrophotographic plate material, charging and/or exposure is performed at a temperature of 15 U to 40 C1, preferably 18 C to 25 C1, and a relative humidity of 60 C. Surprisingly, these defects can be eliminated if the process is carried out under controlled conditions such that the ratio is 60% to 50%, preferably 40% to 50%.

A second feature of the present invention is that an electrophotographic plate-making machine is provided with a mechanism for controlling the temperature and relative humidity to predetermined conditions, particularly in specific parts of the plate-making machine, such as a material presetting part, a charging part, and/or an exposure part. That's what happened. Although it is known that an electrophotographic copying machine is equipped with a heating device to lower the relative humidity, it has not been done to provide a mechanism for controlling the temperature and humidity of a specific part.

Furthermore, in order not to obstruct the projection optical system in the exposure section,
It is also a feature of the present invention that the exposed surface of the electrophotographic material is maintained at a predetermined temperature/humidity condition by the formation of a controlled air layer.

The plate-making machine used in the present invention is comprised of commonly known components and a temperature/humidity adjustment section. That is, it consists of a presetting section for plate-making materials, a charging section, an exposure section, a developing section, a fixing section, a stacking section for printing plates, a document holder, and a projection optical system, and a temperature/humidity adjustment section is either built in or added to it. .

The temperature/humidity adjustment section is composed of a heating mechanism and/or cooling mechanism and a blower fan, and is configured to send air controlled to a predetermined temperature and humidity to at least the charging section and/or the exposure section of the plate making machine. .

Hereinafter, the present invention will be described using the plate making machine illustrated in FIG. 1, but the plate making machine used in the present invention is not limited to this, and various modifications can be made.

In the figure, the plate-making machine has a plate-making material presetting section 2 that holds the electrophotographic plate-making material 11 as a roll or sheet;
A charging unit 6 that uniformly charges the plate-making material by corona discharge;
The belt 1 is fed out by the feed row 912.13.14.
Exposure section 4 that imagewise exposes the plate-making material set in 8; Development section 5 that develops the image-exposed plate-making material with liquid toner; Fixing section 6 that fixes the developed toner image by heat or pressure; Fixed printing plate a stacking section 7 that sends out and stacks the documents using feed rollers 15, 16, and 17; a document mounting table 8; a document that projects the document;
It consists of a projection optical system 9 that exposes the plate-making material set in the exposure section 4 through a reflecting mirror 10; and a temperature/humidity adjustment section 1 for adjusting the temperature and humidity, which is a feature of the present invention. There is.

In the figure, 20 is an exposure light source, and 21 is a developer tank.

The temperature/humidity adjustment section 1 includes a cooling mechanism 22, a heating mechanism 25,
and a blower fan 24.

The air that has been adjusted to predetermined conditions in the temperature/humidity adjustment section 1 is sent to a chainnomy that includes a preset section 2 and a charging section 6.
The temperature and/or humidity of the preset section 2 and the charging section 6 are controlled. This is based on the fact that, as a feature of the plate-making material, the charging condition has a relatively large dependence on temperature and humidity, and the exposure section 4-1 and the developing section 51 have a greater dependence on humidity than on temperature, and furthermore, the response to humidity is relatively slow. This means that it is sufficient to control the temperature and humidity of the preset section 2 and charging section 3. Furthermore, the slit 1 serves as the outlet for the plate-making material.
From 9 the air flows out along the material surface, making it possible to substantially control the temperature and/or humidity.

Furthermore, by controlling the temperature/humidity of the charging section 6, the developing section 5 can be substantially isolated, and the solvent commonly used in wet electrophotography is vaporized, allowing it to be used as a charging means commonly used in electrophotography. This has the effect of eliminating the risk of entering the corona discharge section 2 and causing an explosion.

In the plate-making machine illustrated in FIG. 1 above, air controlled to predetermined conditions by the temperature/humidity adjustment section 1 was shown to flow sequentially through the preset section, the charging section, the exposure section, the developing section, etc.; however, Air may be sent to each part separately.

Next, the present invention will be explained with reference to examples.

Example [Plate making was performed using the plate making machine shown in Figure 1.

The temperature and humidity conditions in the divided zones 2 and 6 in Figure 1 were varied in various ways, and two types of materials were passed through them.

The toner used is Beno-Master toner manufactured by Aitchik Co., Ltd.

The results are shown in Table 1.

From these results, it is understood that the plate making method according to the present invention is excellent.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing one example of a plate-making machine that can be used in the present invention. In the figure, 2 is the preset section, 5 is the charging section, 4 is the exposure section, 5 is the toner development section, 6 is the fixing section, 9 is the exposure optical system, 1 is the temperature/humidity adjustment section, (and 3 other people) Procedure Amendment ridge 58'l" 611/ri 1 Patent Application No. 112758 of 1982 2, Name of the invention: Process for making electrophotographic materials 3, Person making the amendment Relationship with the case Name of patent applicant (520) Fuji Photo Film Co., Ltd. (1) Amend the "Claims" column as shown in the attached sheet. (2) The "Detailed Description of the Invention" column is amended as follows. 1) "Volume resistivity is 1" on page 6, lines 1 to 2 of the specification.
010Ωσ”, “inherent” and “my” are respectively deleted. 2) Insert the following sentence between page 7, line 9 and line 10 (2nd and 6th/e graphs). [Here, the volume resistance is determined from the following equation by sandwiching a sample between two metal circular electrodes with a radius of 2.5 cIrL and reading the current value A when a DC voltage V is applied. Claims 1) Printing is carried out by sequentially feeding an electrophotographic plate material having a photoconductive layer on a support from a preset section of a plate making machine to a charging section, an exposing section, a toner developing section, and a fixing section. In the plate-making method for obtaining a plate, a temperature of 15°C to 40°C and a temperature of 30%
A plate-making method, characterized in that the plate-making process is performed while air whose relative humidity is controlled to be 60% to 60% is flowed through at least a charging section and/or an exposure section of a plate-making machine. 2) According to claim (1), the electrophotographic printing material has a support having a layer of polyolefin or metal foil laminated on at least one surface of a base paper, and a volume resistivity of 101°Ω or less. plate-making method. 6) Air controlled at a temperature of 15° C. to 40° C. and a relative humidity of 50% to 60% is caused to flow along the exposed portion of the electrophotographic plate material in the exposed portion. The plate-making method described in (2). 4) Claims (1) to (1) controlling the air to a temperature of 18°C to 25°C and a relative humidity of 40% to 50%.
3) The plate-making method described in the section ``Collapse''.

Claims (1)

[Claims] 1) An electrophotographic plate-making material having a photoconductive layer on a support is sequentially sent from a preset section of a plate-making machine to a charging section, an exposing section, a toner developing section, and a fixing section for processing. In the plate-making method for obtaining a printing plate, the plate-making process is carried out while flowing air controlled at a temperature of 15 C to 40 C and a relative humidity of 60 C to 60 C through at least a charging section and/or an exposure section of a plate making machine. Characteristic plate making method. 2) According to claim (1), the electrophotographic engraving material has a support having a layer of polyolefin or metal foil laminated on at least one surface of a base paper, and a volume resistivity of 10 Ω1 or less. plate-making method. 3) Temperature of 15C~40t:' and 30%~60
% relative humidity is caused to flow along the exposure surface of the electrophotographic plate material in the exposure section.
The plate-making method described in item 1) or item (2). 4) Controlling the air to a temperature of 18C to 25C and a relative humidity of 40C to 50C.
3) The plate-making method described in any of the sections.