JPH06180515A - Production of machine plate for elecrophotographic offset - Google Patents

Abstract

PURPOSE:To eliminate the remedy for pollution, such as waste water treatment, and to provide the machine plate for offset having high performance, high reliability and a long life. CONSTITUTION:A plate material 1 for printing formed by laminating a hydrophilic polysilane charge transfer layer 5 on an OPC photosensitive body consisting of an org. separated function type photosensitive layer 3 formed on a substrate 2 is subjected to electrostatic charging and exposing to form an electrostatic latent image (stage A); thereafter, this plate material is developed to form a toner image part to form a positive image (stage B). The plate material is then subjected to fixing (stage C), by which the machine plate for offset having the toner image part is obtd. As a result, lipophilic ink is dominently stuck onto this toner image part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an electrophotographic offset printing plate comprising a hydrophilic polymer type charge transport layer formed on an organic photoreceptor (OPC photoreceptor).

[0002]

2. Description of the Related Art A method of manufacturing a printing plate using an electrophotographic technique has already been proposed.
According to the method proposed in Japanese Patent Laid-Open No. 1-143408, after a toner image is formed on a photoconductor, the toner image is transferred to a printing plate material made of a photosensitive resin, and the printing plate material is exposed to light to form a non-printed image. A photochemical reaction is caused in the toner portion, and then development elution treatment is performed to form a printing plate having irregularities corresponding to image information.

However, according to the method proposed above,
Since a printing plate material is required in addition to the photoreceptor, the number of members increases and the process becomes complicated. Furthermore, since development elution is performed by a wet process, large-scale equipment is required for pollution control such as wastewater treatment.

Further, according to Japanese Patent Laid-Open No. 58-72145, a photosensitive material is applied to the surface of a printing plate material, a toner image is formed thereon by an electrophotographic method, and then the printing plate material is entirely covered. It is exposed to cause a photochemical reaction in the non-toner portion, and then is subjected to development elution treatment to obtain a printing plate having irregularities according to image information.

However, this method is an improvement over the above-mentioned technique in that a printing plate material is not required separately from the photoconductor, but on the other hand, since development elution is carried out by a wet process, wastewater treatment, etc. It is still unsolved in that large-scale equipment is required for pollution control.

Furthermore, in the method proposed in JP-A-3-158861, an organic photoconductive compound and a binder resin are used as a photosensitive material used in the above wet process, and the binder resin is a specific material. Although the printing durability and the image quality are improved by the method, since the development elution is carried out by the wet process, there are similar problems.

Moreover, in the conventional electrophotographic printing plate material using the organic semiconductor type charge generating layer, the knowledge that the organic semiconductor type charge generating layer has hydrophilicity has not been announced yet.

The inventors of the present invention have made extensive studies in view of the above circumstances, and as a result, the polysilane-based charge transport material which has been already proposed by the inventors of the present invention, which decomposes upon irradiation with ultraviolet rays, has oxygen in its alkyl group. It was found that the hydrophilicity is remarkably increased when a hydroxyl group is bonded. Moreover, the organic photoconductor (O
It has also been found that when this hydrophilic polysilane-based charge transport layer is laminated on a (PC photoconductor), the offset printing plate can easily obtain a positive image.

The present invention has been completed on the basis of the above-mentioned findings, and its purpose is to provide an electronic printing plate for offset printing, which does not require large-scale equipment and has high performance and high reliability by a simple process. An object of the present invention is to provide a method for manufacturing a photographic offset printing plate.

[0010]

A method of manufacturing an electrophotographic offset printing plate according to a first aspect of the present invention is an organic photoconductor (OP) comprising an organic function-separated photosensitive layer formed on a conductive support.
(C photoconductor), a printing plate material in which a polymer-based charge transport layer having a hydrophilic surface is laminated to form an offset printing plate having a toner image portion by the following steps A to C, and It is characterized in that lipophilic ink is made to adhere onto the image area. A ... The printing plate material is charged and exposed to form an electrostatic latent image. B ... The printing plate material having the electrostatic latent image is developed to form a toner image portion which becomes a positive image. C: The developed printing plate material is fixed.

The present invention will be described in detail below with reference to FIGS. FIG. 1 shows the structure of a printing plate material 1 for making an electrophotographic lithographic printing plate according to the present invention. 2 is a conductive substrate, and the material of the substrate is aluminum, copper, zinc,
For example, a metal such as SUS, nickel, or brass, or a heat resistant resin having a conductive film deposited on the surface thereof may be used. Further, the substrate shape is appropriately selected such as a flat plate shape, a sheet shape, and a drum shape. Then, by forming the organic function separation type photosensitive layer 3 on the substrate 2, the OPC photosensitive body 4 is obtained. A polysilane carrier (charge) transporting layer 5, which is an example of a polymer charge transporting layer having a hydrophilic surface, is formed on the OPC photoreceptor 4 having such a structure to form the plate material 1.

The OPC photosensitive member 4 is usually of a function separation type and is classified into two types depending on the state of the carrier generating material. On the other hand, in the function-separated OPC photosensitive member 4, a carrier generation material (CGM: Carrier Generation Material) is in the form of pigment particles, and a carrier transfer medium (CTM: Carrier).
It is a single-layer type photoconductor that is dispersed in a layer containing r Transport Material), and allows carrier movement between CTMs. For example, instead of applying a pigment dispersion liquid, there is an example of producing a single-layer type photoreceptor having an aggregating phase by a method of treating a thin film in which a dye is uniformly dissolved with a solvent vapor and aggregating the dye. This aggregated phase is generated by the binder polycarbonate and thiapyrylium dye forming a eutectic.

The other function-separated OPC photoreceptor 4 is a carrier (charge) generation layer (CGL: Charge Carrier Generation).
Layer) and carrier (charge) transport layer (CTL: Charge C)
arrier transport layer) are sequentially formed, and are usually laminated in this order. Generally CG
L has a thickness of 1 μm or less, and CTL has a thickness of 10 to 30 μm. Examples of the CGL include polycyclic quinone type, perylene type, perinone type, anthraquinone type, phthalocyanine type, dioxazine type, indigo, thioindigo, squarylium type, azo lake type, azo type, pyrylium type, quinacridone type, cyanine type light, etc. A conductive organic pigment is used, and this pigment is formed by vapor deposition or application of a dispersion liquid.

CTL is required to have good compatibility with CGL, to be excellent in injection efficiency of carriers generated in CGL, and to have high carrier mobility. Although either an electron-donating or electron-withdrawing compound can be used, the development of an electron-donating compound is particularly remarkable,
For example, PVK, oxadiazole, oxazole, pyrazoline, triphenylmethane, hydrazone, triarylamine, N-phenylcarbazole, stilbene and the like can be mentioned.

The photosensitive layer 3 has a function of enhancing the electrostatic latent image contrast as a photoconductor, and the layer thickness for that purpose is preferably in the range of 1 to 30 μm. In addition to being effectively generated, the internal stress of the film does not increase, and the film does not peel when repeatedly used as an offset printing plate. In particular, when the substrate 2 is a flexible sheet, the film is likely to be cracked or peeled off, so that the thickness is preferably 10 μm or less.

Further, in the plate material 1 of FIG. 1, the polysilane carrier transport layer 5 having a hydrophilic surface is formed as one layer. In addition, as shown in FIG. Instead of the single hydrophilic polysilane-based carrier transporting layer 5, a plate material 1a having a laminated structure of a hydrophobic polysilane-based carrier transporting layer 5a and a hydrophilic polysilane-based carrier transporting layer 5b which are already proposed and decomposed by ultraviolet irradiation is used. It may be.

These polysilane-based carrier transport layers 5,
5a and 5b may be, for example, UV-decomposable polysilane, polysilane of the chemical formula shown in Chemical formula 1 is selected, and in order to form the hydrophilic polysilane-based carrier transport layers 5 and 5b, a hydrophobic polysilane-based polysilane is used. For the material, an oxygen atom or a hydroxyl group may be bonded to the alkyl group of this chemical formula.

[0018]

[Chemical 1]

Such polysilanes include diethyl polysilane, dipropyl polysilane, dibutyl polysilane,
Diamylpolysilane, dihexylpolysilane, dicumylpolysilane, ethylpropylpolysilane, ethylamylpolysilane, ethylhexylpolysilane, propylbutylpolysilane, propylamylpolysilane, propylhexylpolysilane, propylphenylpolysilane, propylcumylpolysilane, butylamylpolysilane, butylhexylpolysilane , Butylphenyl polysilane, butyl cumyl polysilane, amyl hexyl polysilane, amyl phenyl polysilane, amyl milk mil polysilane, hexyl phenyl polysilane, hexyl mil polysilane, phenyl cumyl polysilane, ethyl butyl polysilane, phenyl ethyl polysilane, cumyl ethyl polysilane, Examples include diphenyl polysilane. The thickness of the polysilane-based carrier transport layer 5 is appropriately set as an offset printing plate and is preferably 0.5 to 10 μm, preferably 1 to 5 μm.

The carrier transport layer 5 is formed by a dip coating method or a roll coater method. For example, when forming a carrier transport layer of cumylethylpolysilane, the starting material is cumylethyldichlorosilane, which is dechlorinated and polymerized to produce cumylethylpolysilane. This molecular weight is usually on the order of thousands to millions. The polysilane thus generated is dissolved in a solvent such as toluene or tetrahydrofuran, and the OPC photosensitive member 4 is dipped in the solution and applied. After that, by drying with hot air at about 100 ° C., the polysilane-based carrier transport layer 5 is formed on the photosensitive layer 3, and the printing plate material 1 is completed.

Next, a method of manufacturing the electrophotographic offset printing plate according to the present invention will be described with reference to FIGS. This manufacturing method includes the following steps A to C or steps A to D, and each step will be described in detail in order. Step A: (Charging / Exposure / Electrostatic Latent Image) As shown in FIG. 3, the entire surface of the printing plate material 1 as a photoconductor is uniformly charged by corona discharge or the like. The charging polarity is
When polysilane is used, it is usually negatively charged because it exhibits negative chargeability (hole transport property). The negative charging is not the only option, and positive charging may be used.

Then, as shown in FIG. 4, light corresponding to image information is selectively irradiated to form an electrostatic latent image by negative charges on the surface of the photoconductor. The light incidence means may be an analog recording system in which a plate-making original is irradiated with light from a halogen lamp or the like and the reflected light is directly imaged on a photoconductor, as in a copying machine, or He-Ne, Ar. , Laser diode,
A so-called digital recording method in which light is modulated by a LED head, an EL head, a liquid crystal shutter, or the like in accordance with recording information and is irradiated may be used. In this digital recording method, it becomes possible to make an application in which a manuscript transmitted from a remote place using a digital line is directly plate-made to print a newspaper, which allows newspaper printing to be performed quickly and in a simple process. It is useful. In this case, it is possible to configure a system in which a buffer stage is provided on the receiving side, and after performing the typesetting / calibration there, a signal is input to the recording unit. In this way, for example, it becomes possible to manufacture newspapers by receiving individual newspaper article manuscripts from a plurality of senders at one receiver side and making a plate.

Step B: (Development) Next, as shown in FIG. 5, a hydrophobic (lipophilic) toner 6 is dispersed on the surface of the photoconductor to form a toner image corresponding to image information. In this development, various electrophotographic development methods already proposed can be used.
High-definition images can be produced by dry development using a component developer or a two-component developer or liquid development in which developer particles are dispersed in a developer.

Step C: (Fixing) After forming the toner image, the toner image 7 is fixed by a heating means such as a lamp or a heat fixing roller, whereby the electrophotographic offset printing as shown in FIG. Version 8
To make. By this fixing, the toner 6 was melted and deformed, the coverage of the surface of the plate material was increased, and a printing plate with good contrast could be manufactured.

Thus, by the steps A to C, the area other than the toner image 7, that is, the exposed surface 9 of the hydrophilic polysilane-based charge transport layer is repelled by the oil-based ink due to its remarkable hydrophilicity, and its half surface, The oil-based ink is dominantly placed on the toner image 7.

In the present invention, if the hydrophilicity of the exposed surface 9 of the hydrophilic polysilane-based charge transport layer is insufficient even by the above steps A to C, the following step D is continued. By doing so, the performance of the offset printing plate 8 can be complemented or enhanced.

Step D: (Corona discharge) In this step, the offset printing plate 8 obtained in Step C is exposed to corona discharge to further increase the hydrophilicity of the exposed surface 9 of the polysilane-based charge transport layer, As a result, the oily ink is repelled on the exposed surface 9 due to its remarkable hydrophilicity, and the oily ink is predominantly placed on the toner image 7.

As described above, according to the above manufacturing method, A to
The offset printing plate 8 can be manufactured while eliminating the need for ultraviolet irradiation in the steps C or A to D, whereby a separate printing plate material is not required and the number of members is reduced, Furthermore, since chemical development elution processing by wet process is not performed, large-scale equipment is not required for pollution control such as wastewater treatment, and as a result, high performance and highly reliable offset printing plate can be provided by a simple device. It was

Next, examples of the present invention will be described.

[0030]

【Example】

(Example 1) Titanyl phthalocyanine was vacuum-deposited on an aluminum vapor-deposited film whose surface was completely washed to give a thickness of 0.5 μm.
CGL was formed. Next, this film was immersed in a solution of 4- (diethylamino) benzaldehyde diphenylhydrazone and polycarbonate in a weight ratio of 1: 1 in a solution of carbon tetrachloride, dried at 100 ° C., and then dried to 4 μm.
CTLs were formed. Thereafter, this film was subjected to dechlorination polymerization of di (4-tri-n-butylsiloxybutyl) dichlorosilane and then desilylated with tri-n-butylammonium fluoride to obtain an average molecular weight of about 50. Immerse ten thousand di (4-hydroxybutyl) polysilane in a solution of ethyl alcohol, then 10
It was dried with hot air at 0 ° C. In this way, a hydrophilic polysilane-based charge transport layer having a thickness of 1 μm was formed to produce a printing plate material.

Next, the surface of the plate material is corona-charged with a DC voltage of -5 kV, and about -600 V is applied over the entire surface.
Was uniformly charged. Thereafter, a halogen lamp was used to form an image of reflected light from the original on the surface of the plate material to form an electrostatic latent image.

Next, the substrate of the plate material was developed with a negatively charged toner while a bias of 100 V was applied, whereby a high-definition image could be produced.

The toner image of the high-definition image corresponding to the image information is formed in this way, and the toner image is fixed by the lamp, whereby the toner image can be made to be the area where the oil-based ink is attached. did it.

The offset printing plate thus obtained was used to print with an oil-based ink by an offset printing method, and as a result, high resolution printing could be performed. Further, even when the abrasion resistance test corresponding to the printing of 50,000 sheets was performed with this offset printing plate and then the printing was performed again, it was possible to perform printing with almost no deterioration in resolution from the initial stage.

(Example 2) Next, an offset printing plate was once manufactured by the same manufacturing method as in (Example 1), and thereafter, the surface of the plate material was exposed to corona discharge by a DC voltage of -7 kV to transport polysilane charge. The exposed surface of the layer was made even more hydrophilic, which caused the oily ink to be repelled on the exposed surface due to its marked hydrophilicity and, on the other hand, the oily ink to dominate the toner image.

The offset printing plate thus obtained was used to print with an oil-based ink by the offset printing method, and as a result, high resolution printing could be performed. Further, even when the abrasion resistance test corresponding to the printing of 60,000 sheets was performed with this offset printing plate and then printing was performed again, it was possible to perform printing with almost no deterioration in resolution from the initial stage.

The present invention is not limited to the above embodiments, and various modifications and improvements can be made without departing from the scope of the present invention. For example, although a polysilane carrier (charge) transport layer was used as an example of the polymer charge transport layer having a hydrophilic surface, the same type of polymer material may be used.

[0038]

As described above, when offset printing is performed using the electrophotographic printing plate obtained by the production method of the present invention, high resolution and printing with high printing durability can be performed.
As a result, it can be applied to printing a large number of copies such as newspaper printing, and there is no fear of lead pollution problems as in conventional lead alloy plate making.

Further, in the present invention, since the electrostatic latent image can be formed easily and in a short time by laser scanning, there is an advantage that the manufacturing time is shortened and the manufacturing cost is thereby reduced.

Further, according to the present invention, automated rapid plate making can be realized by combining with a transmission system using a digital communication line.

Further, in the method for producing an electrophotographic printing plate according to the present invention, it is not necessary to irradiate ultraviolet rays on the printing plate material in which the OPC photosensitive member and the hydrophilic polymer type charge transport layer are combined. , No need for separate printing plates, the number of parts is reduced, and development is done by a dry process, so large equipment is not required for pollution control such as wastewater treatment. We were able to provide highly reliable offset printing plates.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an electrophotographic printing plate material of the present invention.

FIG. 2 is a sectional view showing an electrophotographic printing plate material of the present invention.

FIG. 3 is a cross-sectional view showing a plate making process according to the present invention.

FIG. 4 is a cross-sectional view showing a plate making process according to the present invention.

FIG. 5 is a cross-sectional view showing a plate making process according to the present invention.

FIG. 6 is a cross-sectional view showing a plate making process according to the present invention.

[Explanation of symbols]

 1 Printing Plate Material 2 Substrate 3 Organic Functional Separation Type Photosensitive Layer 4 OPC Photosensitive Member 5 Hydrophilic Polysilane Type Carrier Transport Layer 6 Toner 8 Offset Plate 9 Exposed Surface of Hydrophilic Polysilane Type Charge Transport Layer

Claims (1)

[Claims] 1. A printing plate material comprising a polymer-based charge transport layer having a hydrophilic surface, which is laminated on an organic photoreceptor comprising an organic function-separated photosensitive layer formed on a conductive support. Production of an electrophotographic offset printing plate, characterized in that an offset printing plate having a toner image portion is formed by the following steps A to C, and a lipophilic ink is adhered onto the toner image portion. Method. A ... The printing plate material is charged and exposed to form an electrostatic latent image. B ... The printing plate material having the electrostatic latent image is developed to form a toner image portion which becomes a positive image. C: The developed printing plate material is fixed.