JPH0545939A - Electrophotographic planographic printing original plate - Google Patents

Abstract

PURPOSE:To prevent the generation of the transportation trouble in an engraving machine and automatic printing machine by using the electrophotographic planographic printing original plate having the specific value of Clark stiffness in a vertical direction. CONSTITUTION:The electrophotographic planographic printing original plate which does not generate transportation trouble in the engraving machine and automatic printing machine occurring in the weakness and strength of the stiffness of the original plate and has good air permeability is obtd. by confining the value of the Clark stiffness in the vertical direction of the planographic printing original plate within a 100 to 250cm<3>/100 range. Paper, metallic foil, plastic films or the composite thereof is used as the base material of the original plate. An intermediate layer and a back coating layer may be provided on one surface of the base material in order to enhance the water resistance and conductivity of the base material. Such layer is formed by applying a resin liquid prepd. by mixing clay, sericite, calcium carbonate, starch, polyvinyl alcohol, conductive material, crosslinking agent, etc., with a synthetic resin emulsion on the above-mentioned layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic lithographic printing plate precursor having good plateability in plate making machines and automatic printing machines.

[0002]

2. Description of the Related Art Generally, an electrophotographic lithographic printing plate precursor is constructed by providing a layer containing an inorganic or organic photoconductive substance on a substrate having properties such as conductivity and water resistance. As the material, a sheet-like substance such as paper, metal foil, film, or a composite thereof to which a conductive substance is added is used.

The photoconductive layer is a layer on which images are formed by an electrophotographic method and contains a photo-semiconductor as a basic component. Usually, an inorganic optical semiconductor such as zinc oxide, titanium dioxide, or cadmium sulfide dispersed in an insulating adhesive resin, or an organic optical semiconductor such as polyvinylcarbazole is used.

In recent years, with the increase in printed matter, it has become essential to increase the plate making speed. Higher plate making speed can be realized by improving the transport speed of the original plate, shortening the charging, exposing, developing and fixing time, etc., but the most effective improvement in transport speed and shortening the exposure time is the plate making machine. The improvement of the transport mechanism and the improvement of illumination intensity have been mainly studied.

However, with the increase in the speed of transporting the original plate, problems such as defective biting in the transport rolls and bending and misalignment in the transport guides have become more frequent.

On the other hand, due to an increase in printed materials and lack of manpower, automatic printing machines having automatic plate feeding and plate discharging functions have been widely used, and printing speed has been increased.

However, as the plate feeding and plate discharging speeds are increased, problems such as bending of the plate feeding roll and the conveying guide, poor gripping of the plate during plate feeding, and bending of the plate during discharging and curling of the plate due to curl occur. It's coming.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electrophotographic lithographic printing plate precursor having good plate-passing property, which does not cause transport troubles in such a plate making machine or automatic printing machine.

[0009]

Means for Solving the Problems As a result of investigations by the present inventors on the relationship between the plateability of a plate making machine or an automatic printing machine and the rigidity of an electrophotographic planographic printing original plate, the Clarke rigidity of the original plate in the longitudinal direction was determined. By keeping it in an appropriate range, troubles such as biting in the transport roll of the plate making machine, bending and misalignment in the transport guide, bending in the transport guide of the automatic printing machine, poor gripping of the plate during plate feeding, and bending during plate ejection We have found that problems such as plate clogging due to curl can be avoided. The longitudinal Clark stiffness is to prepare a master in the range of 100~250cm ^3/100, were tested, both found to be passing version of plate-making machines and automatic printing machine is good, the The invention has been reached.

[0010] In the present invention, longitudinal Clark stiffness of the electrophotographic lithographic printing plate precursor is, 100~250cm ^3/1
00 is desirable. If vertical Clark stiffness is less than 100 cm ^3/100 is bent in the conveying guide plate making machine for the waist of the original is weak or shifted, the plate clogging due bending and during plate discharge bend in the conveyance guide of the automatic printing machine Such troubles occur. In addition, the original Clark stiffness is 250 cm.
^When it exceeds 3/100, the curl curl becomes strong because the original plate is too stiff, and the bite on the transport roll of the plate making machine is poor, the plate is not held properly during plate feeding by the automatic printing machine, and the plate is curled during plate ejection. Problems such as clogging occur.

In the present invention, the photoconductive layer refers to one which is imaged by an electrophotographic method and contains an optical semiconductor as its basic component. Usually, an inorganic optical semiconductor such as zinc oxide, titanium dioxide or cadmium sulfide dispersed in an insulating adhesive resin, or an organic optical semiconductor such as polyvinylcarbazole is used.

In the present invention, paper, metal foil,
A sheet material such as a film or a composite thereof is used.

In the present invention, an intermediate layer may be provided on one side of the substrate in order to enhance the water resistance and conductivity of the substrate. In such an intermediate layer, a synthetic resin emulsion is usually added if necessary. Clay, sericite, pigments such as calcium carbonate, water-soluble resins such as starch and polyvinyl alcohol,
The mixture is applied with a conductive agent, a cross-linking agent, etc.

In the present invention, a backing layer may be provided on the side of the base material opposite to the intermediate layer in order to enhance water resistance and conductivity of the base material. Such backing layer is usually made of synthetic resin. The emulsion is mixed with a pigment such as clay, sericite or calcium carbonate, a water-soluble resin such as starch or polyvinyl alcohol, a conductive agent, a cross-linking agent and the like, if necessary, and then applied.

[0015]

[Action] In the present invention, by keeping the vertical Clark stiffness of the original onto a range of 100~250cm ^3/100, the conveyance troubles in plate-making machines and automatic printing machine due to weakness and strength of the original hip It is possible to obtain an electrophotographic lithographic printing plate precursor that does not generate and has good plateability.

[0016]

EXAMPLES The present invention will now be described in more detail by way of examples, which should not be construed as limiting the invention thereto. All parts and% shown below are based on weight.

Example 1 A single-side coated paper was obtained by applying an intermediate layer having the following composition to one side of a wood free paper having a basis weight of 115 g / m ^{2 so} that the dry coating amount was 10 g / m ² and drying. (Intermediate layer composition) Inorganic pigment containing sericite (Zyklite TMC, manufactured by Zyklite Chemicals, 50% aqueous dispersion): 100 parts Carboxyl-modified SBR latex (solid content 48%):
50 parts melamine resin initial condensate (Smirates resin-613,
Sumitomo Chemical, solid content 80%: 4 parts Organic amine salt catalyst (Sumitex Accelerator A)
CX-P, manufactured by Sumitomo Chemical, solid content 35%): 0.4 part Ammonium polystyrene sulfonate (solid content 30)
%): 4 copies

Next, a back coating layer having the following composition was applied to the side opposite to the intermediate layer of this one-side coated paper so that the dry coating amount was 15 g / m ² , and dried to obtain a double-side coated paper. .. (Backcoat layer composition) Kaolin (Hydrasperth, manufactured by Huber, 50% aqueous dispersion): 100 parts Inorganic pigment containing sericite (Zyklite TMC, manufactured by Zyklite Chemical, 50% aqueous dispersion): 100 parts Oxidized starch ( 25% aqueous solution): 40 parts Carboxyl-modified SBR latex (solid content 48%):
100 parts Ammonium polystyrene sulfonate (solid content 30
%): 6 parts melamine resin initial condensate (SUMIREZ RESIN-613,
Sumitomo Chemical, solid content 80%): 4 parts

The double-sided coated paper was smoothed with a super calender to obtain a base material.

Then, a photoconductive layer having the following composition was coated on the surface of the intermediate layer of this substrate so that the dry coating amount was 20 g / m ² , and dried to prepare an electrophotographic printing original plate. Longitudinal Clark stiffness of the original was 227cm ^3/100. (Photoconductive layer composition) Zinc oxide for electrophotography: 200 parts Acrylic resin (50% liquid): 80 parts Rose Bengal (2% methanol solution): 15 parts Xylene: 250 parts

Example 2 An adhesive for dry lamination having the following composition was applied to one side of an aluminum foil having a thickness of 10 μm so that the dry coating amount was 3.0 g / m ² , and the basis weight was 50 g / m ² . Laminated with fine paper. This aluminum foil laminated paper is left at room temperature for 2 days to be subjected to room temperature aging, and then the dry lamination adhesive having the following composition is applied to the other aluminum foil surface to give a dry coating amount of 3.0 g / m ² . And apply again, basis weight 50g
/ M ^{2 It} was laminated with wood free paper. This aluminum foil laminated paper was left at room temperature for 2 days to be aged at room temperature. (Adhesive composition for dry laminate) Polyester polyol resin (BLS-PC21, manufactured by Toyo Morton, solid content 35%): 15 parts Polyisocyanate (CAT-100, manufactured by Toyo Morton, solid content 50%): 1 part Ethyl acetate: 3 parts

Next, the intermediate layer of Example 1 was coated on one side of this aluminum foil laminated paper so that the dry coating amount was 10 g / m ² , and dried to obtain a single-side coated aluminum foil laminated paper.

On the side opposite to the intermediate layer of this single-sided coated aluminum foil laminated paper, the backing layer of Example 1 was applied so that the dry coating amount was 15 g / m ² , and dried to obtain double-sided coated aluminum. A foil laminated paper was obtained.

Then, this double-sided coated aluminum foil laminated paper was smoothed with a super calendar to obtain a base material.

Further, the photoconductive layer of Example 1 was applied to the surface of the intermediate layer of this substrate so that the dry coating amount was 20 g / m ² , and dried to prepare an electrophotographic printing original plate. Longitudinal Clark stiffness of the original was 118cm ^3/100.

Comparative Example 1 The double-sided coated paper in Example 1 was subjected to smoothing treatment by weakening the pressure with a super calender to obtain a base material.

An electrophotographic lithographic printing plate precursor was prepared in exactly the same manner as in Example 1 except that the substrate in Example 1 was changed to the above substrate. Longitudinal Clark stiffness of the original was 289cm ^3/100.

Comparative Example 2 The double-sided coated aluminum foil laminated paper in Example 2 was subjected to smoothing treatment by increasing pressure with a super calender to obtain a base material.

An electrophotographic lithographic printing plate precursor was prepared in exactly the same manner as in Example 2 except that the substrate in Example 2 was changed to the above substrate. Longitudinal Clark stiffness of the original plate was 83cm ^3/100.

These electrophotographic lithographic printing plates were prepared at 20 ° C.
After seasoning under the condition of 65% RH, plate making was carried out with an electrophotographic plate making machine Diafax EP-31V (made by Mitsubishi Paper Mills, a plate making machine for liquid development).

Etching solution for electrophotographic offset master Diafax LOM-OHII (manufactured by Mitsubishi Paper Mills)
Fully automatic offset printing machine Hamada 61
Printing was performed with 2XLA (manufactured by Hamada Printing Machinery).

The evaluation results are collectively shown in Table 1. The plate formability of the plate making machine and the automatic printing machine is represented by the number of plate forms that have a trouble of transport, plate feeding or plate discharge when 100 plate plates are made or printed. The smaller the value, the better the plate formability. Indicates that.

[0033]

[Table 1]

From the results shown in Table 1, it is clear that in Examples 1 and 2, since the longitudinal rigidity of the original plate was appropriate, there was almost no conveyance trouble in the plate making machine and the automatic printing machine. In Comparative Example 1, the longitudinal rigidity of the original plate was too high and the rigidity was too strong. Therefore, biting failure on the transport rolls of the plate making machine, plate holding failure at the time of plate feeding of the automatic printing machine, and curl at the time of plate ejection were caused. A problem such as clogging occurred. In Comparative Example 2, the rigidity of the original plate in the longitudinal direction was too low and the stiffness was too weak, so that the conveyance guide of the plate making machine was bent or misaligned, and the conveyance guide of the automatic printing machine was bent or jammed at the time of plate ejection. Trouble occurred.

[0035]

As is apparent from the above description, according to the present invention, it is possible to obtain an electrophotographic lithographic printing original plate having good plateability without causing a trouble of conveying the original plate in a plate making machine or an automatic printing machine. it can.

Claims (1)

[Claims] 1. An electrophotographic lithographic printing plate precursor comprising a substrate and a photoconductive layer containing a photoconductive substance, wherein the electrophotographic lithographic printing plate precursor has a Clark rigidity of 100 to 25 in the longitudinal direction.
Electrophotographic lithographic printing plate precursor which is a 0 cm ^3/100.