JPH0631889A - Printing plate and printer and printing method using the same - Google Patents

Abstract

PURPOSE:To provide a printing plate whereby engraving, correction and reproduction are greatly facilitated, and a printer and printing method using this. CONSTITUTION:On the surface of an electrically conductive layer 3, an optical semiconductive layer or charge producing layer 2, which absorbs light to create an electrons and hole and changes from nonconducive to conductive, is formed. Further, the surface of the charge producing layer 2 is covered with an ink application layer 1 made of a polymer whose surface changes from hydrophobic (lipophilic) to hydrophilic (lipophobic or no affinity for oil) as a result of charges injected therein.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing plate, a printing machine and a printing method using the printing plate, and more particularly to a wet development type printing plate which is extremely easy to make, correct and reproduce, and a printing machine using the printing plate. And a printing method.

[0002]

2. Description of the Related Art Currently, general offset printing is as follows.

First, a PS plate (presensitized plate) formed by coating a surface of a metal plate with a photosensitive resin is exposed to promote the reaction of the photosensitive resin, and the exposed portion (or vice versa) is chemically reacted. The surface of the metal is exposed by rinsing to obtain a printing plate.

The resin portion remaining on the plate surface is lipophilic (hydrophobic: hy
Since the newly exposed metal surface is hydrophilic (oleophobic or oleophobic), the ink adheres only to the resin part to form a line drawing part when it is brought into contact with it. The ink in the line drawing portion is once transferred to a rubber cylinder and then transferred to paper to obtain a printed matter.

However, since such a printing plate is manufactured outside the printing press, a down time of the printing press and a down time for exchanging the printing plate occur when changing the printing plate.
Also, once a version was created, it could not be modified and replayed.

In order to solve such problems, for example, in JP-A-59-89153 (European Patent Application Publication No. A-101266), the surface of a hydrophilic (oleophobic) printing plate (plate cylinder) is disclosed. There is disclosed a technique in which a printing plate is obtained by uniformly coating a layer with a hydrophobic layer, and irradiating the hydrophobic layer with a charged particle beam according to printing information to selectively remove the layer.

Further, in Japanese Patent Application Laid-Open No. 2-74344 (European Patent Application Publication No. A-352612), electrical control controlled by a printing pattern stored electronically on a conductive and hydrophilic support is disclosed. There is disclosed a technique in which a mechanical control device is provided and a printing plate is obtained by exposing it to a monomer liquid that can become a conductive polymer by an electrode reaction.

[0008]

However, the "printing method and its apparatus" disclosed in Japanese Patent Laid-Open No. 59-89153 has the hydrophilic (oleophobic) property that the plate cylinder surface forms a printing plate. The surface of the plate is cleaned by using an apparatus in a printing machine, further coated with a hydrophobic layer, and the hydrophobic layer is removed by a physical operation controlled by electronically edited printing information to obtain a printing plate. To do. Although the above-described operation is repeatedly performed for the new configuration of the printing plate, there is a problem that the printing process must be interrupted in each step.

Further, in the prior art disclosed in Japanese Patent Application Laid-Open No. 2-74344, since the size of the electrode of the electric control device is the size of one pixel, there is a problem that only a low definition image quality can be obtained. there were.

An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a printing plate which is extremely easy to make, correct and reproduce, and a printing machine and a printing method using the printing plate.

[0011]

In order to achieve the above object, the present invention takes the following means. (1) a printing plate, a conductive layer having electrical conductivity, a charge generation layer which is formed on the surface of the conductive layer and generates charges by receiving light energy, and the charge which is formed on the surface of the charge generation layer and is injected with the charges And an ink coating layer whose surface changes from lipophilic to oleophobic. (2) Using the printing plate described in (1) above, the charge generation layer is irradiated with light according to the printed image to form a latent image on the surface of the ink coating layer, which is distinguished by a lipophilic portion and an oleophobic portion. Then, the ink is applied to the surface of the ink coating layer to adhere the ink only to the lipophilic portion, and the ink is transferred from the ink coating layer to the recording paper,
The printing plate was regenerated by irradiating the entire surface of the ink coating layer with light and grounding the ink coating layer. (3) The printing plate according to (1) above, which is formed into a cylindrical shape so that the ink coating layer is exposed on the outside, a means for applying a voltage to the conductive layer of the printing plate, and the printing plate. Means for irradiating the charge generation layer with light to form a latent image, means for applying ink to the ink application layer, means for bringing the recording paper into contact with the ink application layer and transferring the image to the recording paper, A means for irradiating the entire surface of the ink coating layer with light to regenerate the printing plate was provided.

[0012]

When the printing plate is exposed to light according to the electronically edited print information, the charge generated in the charge generation layer of the light receiving portion is injected into the ink coating layer, and that portion (changes from non-polar to polar). And then become hydrophilic or oleophobic. As a result, a latent image is formed on the non-light-receiving portion, which exhibits ink receptivity and the light-receiving portion exhibits ink repellency. Water is a molecularly polar substance, and oil-based ink is a non-polar substance. Since polar substances or non-polar substances have affinity and good adhesion, when ink is applied to the surface of the ink coating layer, the non-light-receiving part becomes the image part and the light-receiving part becomes the non-image part, so that it functions as a printing plate. become.

After completion of printing, when the conductive layer is electrically grounded and the entire surface is exposed to release charges, the entire surface of the ink coating layer becomes non-polar and the latent image is erased, so that the printing plate is reproduced.

[0014]

1 is a block diagram of a printing plate 1 according to a first embodiment of the present invention.
It is sectional drawing which showed the structure of 0. On the surface of the conductive layer 3 (third layer) having electrical conductivity such as an aluminum plate, selenium, amorphous silicon, phthalocyanine metal complex, etc. absorb light to generate electrons and holes, and are non-conductive. Photo-semiconductor layer or charge generation layer 2 that changes from conductive to conductive
(Second layer) is formed.

Further, the surface of the charge generation layer 2 is injected with electric charges such as polyacetylene, polypyrrole, polythiophene doped with a low molecular weight substance, and the surface property is changed from hydrophobic (lipophilic) to hydrophilic (lipophilic). Oleophobic or oleophobic)
The ink coating layer 1 (first layer) is formed of a high-molecular polymer having conductivity and changing in nature. In the examples described in detail below, a phthalocyanine metal complex is used as the second charge generation layer 2 and polythiophene is used as the first ink coating layer 1.

At the time of plate making, the conductive layer 3 is connected to the power supply device 4. By switching the switch 40, the power supply device 4 can selectively connect the power supplies 41 and 42 having different polarities to the conductive layer 3. In this embodiment, the switch 40 is first switched to the power supply 41 side to apply a DC voltage of 50V.

Next, with respect to the surface of the ink coating layer 1,
Scanning exposure according to print information is performed by a laser beam such as a He-Ne laser, an argon laser, or a semiconductor laser. The laser light is applied to the charge generation layer 2 via the ink coating layer 1.

In the charge generation layer 2, electrons and holes are generated at the light-irradiated portion. Of these, holes are conductive layers 3
The electrons flow into the power supply device 4 via the, and electrons are injected into the ink coating layer 1.

The ink coating layer 1 is essentially lipophilic (hydrophobic), but when electric charges are injected in this way, the portion changes from non-polar to polar and becomes hydrophilic. That is, since the ink does not reach the light-irradiated portion, the surface of the ink coating layer 1 is divided into the image portion and the non-image portion, and the printing plate is completed.

FIG. 3 is a view showing the structure of a printing apparatus according to the second embodiment of the present invention, in which the same symbols as those used above represent the same or equivalent portions. In the printing apparatus of this embodiment,
The first to third layers are formed on the surface of the drum 20.

The printing method by the printing apparatus of the present invention will be described below with reference to the flowchart of FIG.

First step: First, an electric field is applied to the surface of the printing drum 20 by the power supply 15. This electric field is applied to stabilize the charges in the ink coating layer 1.

Second step: The surface of the drum is irradiated with the laser beam 5 according to the electronically edited print information. As a result,
As described above, on the surface of the drum 20, the portion irradiated with the laser beam 5 becomes hydrophilic and the other areas become lipophilic, so that the plate making is completed (step S1).

Third step: dampening water 60 is applied to the surface of the drum 20 by the dampening water conveying roller 61. As a result, the oleophobic property of the hydrophilic part (non-image part) is further enhanced (step S2).

Fourth step: The ink 70 is applied to the surface of the drum 20 by the ink carrying roller 71, and the ink is selectively placed on the area not irradiated with the laser beam 5 (step S3).

Fifth step: The ink on the surface of the drum 20 is transferred to the transfer cylinder 8, and this ink is further transferred to the recording paper 1000 conveyed between the transfer drum 8 and the impression cylinder 9, and the printed matter 1001 is printed.
Is obtained (step S4).

Sixth step: The changeover switch 40 of the power source device 4 is switched to the power source 41 or the power source 42. Although reproduction is possible with any of the power supply polarities, according to the experiments of the present invention and the like, better results were obtained when the polarity was opposite to that at the time of writing (in this case, the power supply 42 side). Next, the entire surface of the plate is exposed to light, the ink coating layer 1 is grounded, and then the switch 40 is turned off (step S5).

At this time, it was confirmed that a current was flowing between the ink coating layer 1 and the ground to discharge. Here, when the ink is applied to the entire surface of the ink application layer 1, the ink exhibits a good affinity even in the exposed portion which has been oleophobic until then,
It was confirmed that the latent image was erased and the printing plate was reproduced.

FIG. 4 is a diagram for explaining a method of manufacturing a printing plate which is a third embodiment of the present invention, and the same reference numerals as those used above represent the same or equivalent portions.

In the following, particularly when polythiophene is used as the first layer (ink coating layer), amorphous silicon is used as the second layer (charge generation layer), and aluminum is used as the third layer (conductive layer). Will be described as an example.

First, monosilane is heated in vacuum to form an amorphous silicon layer as a charge generation layer on the surface of the aluminum conductive layer 3 exposed on the surface of the drum 20.

Then, the aluminum conductive layer 3 is anodized.
And a platinum plate 112 as a cathode, and an electrolyte solution 100
(Thiophene 0.2 mol / liter, Li BF4 0.0
Power supply 11 in 2 mol / l nitrobenzene solution)
0 is energized and a current having a current density of 0.5 mA / cm ² is applied at a voltage of 20 V to cause electrolysis to form a conductive polymer (polythiophene) layer 1 on the surface of the charge generation layer 2.

The illumination lamp 120 in the figure is for obtaining the conductivity of the charge generation layer 2. In addition, Li ion is
The BF4 ion is a doping agent and contributes to the conductivity of polythiophene. Further, thiophene undergoes a polymerization reaction to become polythiophene while being oxidized in the anode.

In the above-mentioned embodiment, the DC voltage is supplied from the power supply 41, but the present invention is not limited to this, and as shown in FIG.
When 3 was set to 50 V, the image quality was superior to that when the DC voltage was applied as described above. This is because, like the power supply 41, there is merely an accumulation of electric charge in the direct current, whereas the alternating power supply 43 electrically polarizes the surface of the printing plate 10 (like a capacitor), and as a result, the dampening water 6 It is thought that this is because the affinity is increased.

A method of manufacturing a printing plate which is the fourth embodiment of the present invention will be described below.

In this embodiment, polythiophene is produced in a solution using a catalyst, and a charge generating substance (photosemiconductor substance) is further added to the ink coating layer 1 and the charge generating layer 2 in FIG. They are integrated to increase mechanical strength.

Separately synthesized powder of a phthalocyanine copper complex was added to a polythiophene solution (solvent: diethyl ether), an aluminum plate serving as the conductive layer 3 was placed on the bottom of the flask, and the solvent was evaporated by heating under reduced pressure with stirring. The weight ratio of the polythiophene solution to the phthalocyanine copper complex was 1: 1.

When the printing plate thus completed was irradiated with laser light to give ink in the same manner as described above, it was confirmed that plate making and reproduction were possible in the same manner as described above.

In the above embodiments, laser light was used as a light source during plate making and reproduction, but the present invention is not limited to this, and a light source such as a tungsten lamp, a halogen lamp or a xenon lamp can be used. You may use.

In the above-described embodiments, aluminum is used as the conductive layer, and light energy is applied to the charge generation layer 2 through the ink coating layer 1. However, as the conductive layer 3, ITO having light transparency is used. May be used to irradiate the charge generation layer 2 with light energy through the conductive layer 3.

[0041]

As described above, according to the present invention, the potential of the printing plate can be controlled, and at the same time, the plate can be made and reproduced only by irradiating the printing plate with light. Platemaking, correction, and reproduction are possible without replacement, and extremely efficient offset printing is possible.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a printing plate that is a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a modified example of the present invention.

FIG. 3 is a diagram showing a structure of a printing apparatus that is a second embodiment of the present invention.

FIG. 4 is a diagram showing a method of manufacturing a printing plate which is a third embodiment of the present invention.

FIG. 5 is a flowchart for explaining a printing method according to the present invention.

[Explanation of symbols]

1 ... Ink coating layer, 2 ... Charge generation layer, 3 ... Conductive layer, 4 ...
Power supply, 5 ... Laser light, 6 ... Dampening water, 7 ... Ink, 8 ... Transfer cylinder, 9 ... Pressure cylinder, 10 ... Printing plate, 15 ... Electric field electrode and bias power supply, 40 ... Switch, 43 ... Alternating power supply, 61 …
Dampening water transfer roller, 71 ... Ink transfer roller, 10
0 ... Electrolyte solution, 110 ... Electrolysis power supply, 112 ... Cathode electrode, 120 ... Illumination lamp, 1000 ... Paper, 1001 ... Printed matter

Claims (5)

[Claims] 1. A conductive layer having electrical conductivity, a charge generation layer formed on the surface of the conductive layer to generate charges by receiving light energy, and a charge generation layer formed on the surface of the charge generation layer. A printing plate characterized by comprising an ink coating layer whose surface changes from lipophilicity to oleophobicity by injecting the electric charge generated in. 2. The at least one of the conductive layer and the ink coating layer is light transmissive.
Printed version as described. 3. A printing method using the printing plate according to claim 1 or 2, wherein the charge generation layer is irradiated with light according to a printed image, and the surface of the ink coating layer is oleophilic and oleophobic. A step of forming a latent image that is distinguished from a part, a step of applying ink to the surface of the ink application layer to adhere the ink only to the lipophilic part, and a step of transferring the ink from the ink application layer to the recording paper And a step of irradiating the entire surface of the ink coating layer with light and grounding the ink coating layer to regenerate the printing plate. 4. The printing plate according to claim 1 or 2,
A printing drum formed in a cylindrical shape so that the ink coating layer is exposed on the outside, a unit for applying a voltage to the conductive layer of the printing plate, and a charge generation layer of the printing plate, according to a print image. A means for irradiating light to form a latent image, a means for applying ink to the ink coating layer, a means for bringing recording paper into contact with the ink coating layer to transfer the image to the recording paper, and the entire surface of the ink coating layer. And a means for irradiating the plate with light to regenerate the printing plate. 5. The printing machine according to claim 4, wherein the voltage applied to the conductive layer is an alternating voltage.