JP2000258929A - Electrostatic printing master plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an electrostatic printing master plate with which images of high density can be continuously formed by incorporating a binder of an org. and inorg. composite material into a light-absorbing layer. SOLUTION: This electrostatic printing master plate 1 consists of a conductive base body 2 having a conductive layer 3 as the surface layer and an insulating pattern layer 5 formed in a specified pattern on the conductive layer 3 with a light-absorbing layer 4 interposed. The binder which constitutes the light-absorbing layer 4 consists of an org. and inorg. composite material. Namely, a coating material containing a metal org. compd. such as a metal alkoxide as well as a light-absorbing substance is applied, dried and hydrolyzed to produce an org. and inorg. composite metal hydroxide, which is then polymerized and condensed to produce a binder comprising the org. and inorg. composite metal. Thus, the binder contains the light-absorbing substance and forms the light-absorbing layer 4. The org. and inorg. composite material as the binder in the light-absorbing layer 4 decreases the affinity of the light-absorbing layer 4 to a toner and prevents the deposition of the toner on the light-absorbing layer 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a master plate used for electrostatic printing, and more particularly, to a master plate capable of using a liquid toner.

[0002]

2. Description of the Related Art An electrostatic printing method has been conventionally used as a kind of printing method. The electrostatic printing method uses an electrostatic printing master plate in which an insulating pattern layer made of an electrically insulating material is formed on a conductive base material. That is, an electrostatic latent image is formed by applying an electric charge to the insulating pattern layer of the electrostatic printing master plate by an electric charge applying means such as corona discharge, and the electrostatic latent image is developed with a dry powder toner charged to the opposite polarity. The dry powder toner on the electrostatic printing master plate is transferred to a printing medium and fixed by heating, and continuous printing is performed by repeating this operation.

However, in the conventional image formation using the electrostatic printing master plate, the dry powder toner is used as described above, but the particle diameter of the dry powder toner is relatively large, about 5 to 50 μm. Therefore, there is a problem that it is difficult to form an image that requires a high resolution. Further, after transferring the dry powder toner on the electrostatic printing master plate to the printing medium, heating for fixing the dry powder toner is required, but the printing medium is heat resistant such as a polyolefin film. In the case of a low resin film, there is also a problem that heat shrinkage occurs at the printing stage. For this reason, an image is formed by electrostatic printing using liquid toner.

[0004]

A conventional electrostatic printing master plate in which a liquid toner can be used is, for example, a pattern formed on an insulating layer provided on a conductive substrate via a light absorbing layer. Laser irradiation was performed in such a manner that the insulating layer was destroyed and removed by the heat generated by the light absorbing layer in the irradiated portion, thereby partially exposing the light absorbing layer to form an insulating pattern layer.

[0005] However, when electrostatic printing using liquid toner is performed using such an electrostatic printing master plate, there is a problem that the image density of a printed matter decreases as the number of printings increases. This is because when the binder of the light-absorbing layer is made of an organic material, the toner is also an organic material, so that the affinity between the light-absorbing layer and the toner is high, and the light-absorbing layer is exposed as the number of printings increases. It is considered that the amount of toner transferred to the printing medium is reduced as a result of the toner being deposited on the substrate and the potential difference between the exposed portion of the light absorbing layer and the insulating pattern layer being reduced.

The present invention has been made in view of such circumstances, and has as its object to provide an electrostatic printing master plate capable of continuously forming a high-density image.

[0007]

In order to achieve the above object, the present invention provides a conductive base material having a conductive layer at least on a surface portion thereof, and a light absorbing material on the conductive layer of the conductive base material. An insulating pattern layer formed with a conductive layer interposed therebetween, and the light absorbing layer is configured to contain a binder made of an organic-inorganic composite material.

In the present invention, the organic-inorganic composite material contained in the light-absorbing layer as a binder functions to lower the affinity of the light-absorbing layer for the toner, and the toner on the light-absorbing layer Accumulation is prevented.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic sectional view showing one embodiment of the electrostatic printing master plate of the present invention. In FIG. 1, an electrostatic printing master plate 1 of the present invention is formed in a predetermined pattern via a conductive base material 2 having a conductive layer 3 on a surface layer portion and a light absorbing layer 4 on the conductive layer 3. And an insulating pattern layer 5.

The conductive substrate 2 constituting the electrostatic printing master plate 1 is provided with the conductive layer 3 at least on the surface layer as described above. A laminate with a conductive layer provided on the surface of the material, a substrate having conductivity as a whole, or the like can be used. Specific examples include a laminate composed of a resin film and a conductive layer provided thereon, a metal plate or foil, and a conductive treated paper.

Examples of the above resin film include polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-
Vinyl acetate copolymer, saponified ethylene-vinyl acetate copolymer, ethylene-α-olefin copolymer elastomer, acid-modified polyolefin, styrene-butadiene-acrylonitrile copolymer, polyamide, polycarbonate, polysulfone, polyacetal, polymethyl methacrylate , Polyphenylene oxide, polyurethane, polyethylene terephthalate, polybutadiene terephthalate, nylon or the like, or a mixture thereof (a co-extruded film or the like), a laminate, or the like.

The conductive layer 3 provided on the above-mentioned resin film has conductivity, and can be formed of, for example, a material having a volume resistivity of 10 ⁸ Ω · cm or less. Specifically, Au, Ag, Cu, P
t, Zn, Pb, Cd, Ni, Co, Sn, In, A
1, Mg, Ti, Be, Li, Ga, Se, Te, C
r, Mn, Sb, and Bi alone, or an alloy or oxide alloy of these, carbon black, or an organic conductive material. The conductive layer 3 can be formed by adhering a thin film made of the above-mentioned material on a resin film. Or
The thin film can be formed by mixing fine particles of the above materials with a binder, applying the mixture by coating, and drying to form a thin film. The thickness of the conductive layer 3 is such that the conductive substrate 2 can be provided with conductivity, for example, 10 to 50000 °, preferably 10 to 50000 °.
It can be about 0 to 1000 °.

The light-absorbing layer 4 constituting the electrostatic printing master plate 1 contains at least a light-absorbing substance and a binder, and converts light irradiated at the time of forming the insulating pattern layer 5 into heat energy with high efficiency. It is intended to do so.

The light-absorbing substance contained in the light-absorbing layer 4 is added for the purpose of converting the energy of the irradiation light into heat energy with high efficiency. For example, a substance that absorbs all or a part of the wavelength range of light emitted from a laser, a light emitting diode (LED), or the like. Specifically, fine powder or complex of a compound containing copper or iron as a light absorbing substance for near-infrared light (wavelength range 700 to 2000 nm); carbon black; anthraquinone compound, phthalocyanine compound, chromium, cobalt metal complex salt Compound,
Tungsten hexachloride and tin chloride dissolved in methyl methacrylate (MMA) syrup and polymerized, dithiol-based metal complex (mainly nickel complex), squarylium compound, acetylene-based polymer doped with oxidant in gas or liquid phase Materials, a material obtained by allowing cupric sulfide to act on thiourea, and many inorganic complexes and organic compounds such as an immonium-based material. Further, as a light absorbing substance for visible light (wavelength 400 to 700 nm), carbon black; nitroso dye, nitro dye,
Azo dye, stilbene azo dye, ketimine dye, triphenylmethane dye, xanthene dye, acridine dye, quinoline dye, methine, polymethine dye, thiazole dye, indamine, indophenol dye, azine dye, oxazine dye, thiazine dye, sulfur dye, Organic dyes such as aminoketone, oxyketone dye, anthraquinone dye, indigoid dye, and phthalocyanine dye; Z
n, Cu, Al, Pb, Cr, Cd, Fe, Co, K,
A simple alloy such as Na, Ti, Hg, Sr, Ca, Ba, Si, and S, or an inorganic compound such as an oxide, a hydroxide, or a composite thereof can be given. Such a light absorbing substance is contained in the light absorbing layer 4 in an amount of about 5 to 90% by weight. If the content of the light-absorbing substance is less than 5% by weight, the amount of heat energy converted from light energy in the light-absorbing layer 4 is insufficient, and the accuracy of forming the insulating pattern layer 5 is reduced. If the content is more than 10% by weight, the film formability of the light absorbing layer 4 is undesirably reduced.

The binder constituting the light absorbing layer 4 is made of an organic-inorganic composite material. That is, an organic-inorganic composite metal hydroxide obtained by hydrolysis by applying a coating containing a metal organic compound such as a metal alkoxide, a metal acetyl acetate, and a metal carboxylate together with the above light-absorbing substance and drying the coating. Is polycondensed to form a binder made of an organic-inorganic composite material, and the light-absorbing layer 4 containing a light-absorbing substance in the binder can be formed. Examples of the metal used for the metal organic compound include Li, Na, K, Rb, Cs, Be, and M.
g, Ca, Sr, Ba, Ra, Po, Cr, Mo, W,
Mn, Tc, Re, Fe, Ru, Os, Co, Rh, I
r, Ni, Pd, Pt, Cu, Ag, Au, Zn, C
d, Hg, Si, Pb, Sn, Sb, Sc, Y, Nb,
Examples include metals such as Ln, Al, Ga, In, Tl, and Bi.

The thickness of the light absorbing layer 4 can be, for example, about 0.1 to 5 μm. When the thickness of the light absorbing layer 4 is less than 0.1 μm, the irradiated light energy cannot be sufficiently converted into heat energy, which hinders the formation of the insulating pattern layer 5. Also, 5
If it exceeds μm, it is difficult to transfer the converted thermal energy to the insulating layer described later, which is not preferable.

The insulating pattern layer 5 constituting the electrostatic printing master plate 1 is provided with an insulating layer containing at least an insulating substance on the light absorbing layer 4 and irradiating the insulating layer with light. Is formed by removing.

Examples of the insulating material for forming the insulating pattern layer 5 include natural waxes such as spermaceti, beeswax, carnauba wax, candelilla wax, wood wax, montan wax, and lanolin wax, paraffin wax, and microcrystalline. Waxes, ester waxes, oxidized waxes, low molecular weight polyethylene waxes, montan waxes, synthetic waxes such as chlorinated paraffin, higher fatty acids such as lauric acid, myristic acid, palmitic acid, stearic acid, phlomenic acid, behenic acid, stearyl alcohol, behe Higher alcohols such as nin alcohol, fatty acid esters of sucrose, esters such as fatty acid esters of sulbitan, amides such as stearinamide and oleinamide, or monomers such as vinyl acetate, vinyl alcohol, styrene, α- Rusuchiren, (meth) acrylic acid, (meth) acrylic acid ester, fluorine-containing (meth) acrylic acid derivative, acrylonitrile, ethylene,
At least one selected from olefins such as propylene
Polymers obtained by polymerizing various monomers, cellulose acetate, ethyl cellulose, cellulose derivatives such as nitrocellulose, polyamide, polyimide, polyester,
Polycarbonate, polysulfone, polyacetal, polyphenylene oxide, polyurethane, epoxy resin,
Examples include polymers such as phenolic resins, petroleum resins, rubbers, silicone resins, and fluororesins, and these can be used alone or in combination of two or more. The insulating substance contained in the insulating pattern layer 5 has a volume resistivity of 10 ¹² to 1 of the insulating pattern layer 5.
It can be set appropriately so as to be in the range of 0 ¹⁸ Ω · cm.

The insulating pattern layer 5 contains a filler having an average particle size of 1 μm or less in an amount of 30% by weight or less in order to improve the film breakability during pattern formation by light irradiation on the insulating layer. You may.

The thickness of the insulating pattern layer 5 is as follows:
For example, it can be about 0.3 to 10 μm. When the thickness is less than 0.3 μm, the charged voltage is low and the amount of toner adhered is small, so that the contrast of the obtained printed matter is low. The layer has poor film cutting properties, and it is difficult to form a high-definition pattern. Insulating pattern layer 5
And the minimum width of the region where the insulating pattern layer 5 is not formed can be set to 0.1 μm or more.

Here, the insulating solvent used for the liquid toner is not particularly limited as long as it is electrically insulating.
Esso's Isopar G, C, E, H, L, M, and IP Solvents manufactured by Esso, which are isoparaffinic solvents as hydrocarbons, and Shell Petroleum's oil naphthas, etc. Naphtha No. Other examples include fluorinated hydrocarbons, silicon, and the like.

Next, a method for manufacturing the electrostatic printing master plate of the present invention will be described. FIG. 2 shows an electrostatic printing master plate 1
It is a flowchart showing an example of the manufacturing method of. In FIG.
First, a light-absorbing layer 4 and an insulating layer 5 'are laminated on the conductive layer 3 of the conductive substrate 2 (FIG. 2A).

The light absorbing layer 4 is coated with a coating material containing a metal alkoxide, a metal acetyl acetate, a metal organic compound such as a metal carboxylate together with a light absorbing substance or the like on the conductive layer 13 by a known coating method and dried. Can be formed. Also, the insulating layer 5 'is a layer, such as a volume resistivity in the range of 10 ¹² ~10 ¹⁸ Ω · cm. The insulating layer 5 ′ can be formed by applying a coating liquid containing an insulating substance or the like on the light absorbing layer 4 by a known coating method and drying the coating liquid. The thickness can be set in consideration of the thickness of the characteristic pattern layer 5.

Next, the insulating layer 5 'is irradiated with light in a desired pattern (FIG. 2B). In the illustrated example, only the regions A and B are irradiated with light. The irradiation light is Al ₂ O ₃ , CaF
₂ , solid lasers represented by CaWO ₄ , MgF ₂ , barium crown glass, etc., gas lasers represented by CO ₂ , Ar, etc., chelate compound solutions or organic dye solutions such as phthalocyanine, cryptocyanine, rhodamine or selenium oxychloride Lasers using inorganic liquids such as Al, Ga, As, In, P, Sb, Pb, Se,
Light emitted from a laser such as a semiconductor laser typified by a crystal composed of two or more elements selected from Te or the like can be used, and the light absorbing substance contained in the light absorbing layer 4 can be used. Can be appropriately selected from the relationship.
The light irradiation on the insulating layer 5 ′ can be performed by, for example, drawing with a light beam, irradiation through a desired mask, or the like. The amount of light irradiation can be set in consideration of the light source used, the material of the light absorbing substance contained in the light absorbing layer 4, and the like.

In such light irradiation, the insulating layer 5 '
Is transmitted through this insulating layer 5 ′ and converted into heat energy in the light absorbing layer 4 by the light absorbing substance. Then, since this heat energy is transmitted to the insulating layer 5 'in the light irradiation area, the insulation layer 5' is broken only in the light irradiation area.

Next, the surface of the insulating layer 5 'is wiped off with a cloth impregnated with a predetermined solvent, or the predetermined layer of the solvent is applied to remove the insulating layer 5' in the light irradiation area. Then, the remaining insulating layer 5 is formed on the light absorbing layer 4.
Is formed, and the electrostatic printing master plate 1 is obtained (FIG. 2C).

Next, electrostatic printing using the electrostatic printing master plate 1 of the present invention will be described. FIG. 3 is a schematic configuration diagram illustrating an example of the electrostatic printing apparatus. In FIG. 3, the electrostatic printing device 1
1 includes a plate cylinder 12, chargers 13 and 15, a developing unit 14, and a plurality of transport rollers 16 for transporting the printing medium 21.

In the illustrated example, the above-described electrostatic printing master plate 1 of the present invention is mounted on the plate cylinder 12. This plate cylinder 12
Is rotated in the direction of the arrow, the charging device 13 charges the insulating pattern layer 5 of the electrostatic printing master plate 1 to a predetermined polarity. In the illustrated example, the charger 13 is of a positive charge type, and the insulating pattern layer 5 is charged to the anode.

Next, as the plate cylinder 12 rotates, the charged insulating pattern layer 5 reaches the developing section 14. The developing unit 14 includes a container 14a for holding a liquid toner containing the charged toner T, a developing roller 14b for attaching the charged toner T to the electrostatic printing master plate 1 from the liquid toner, and an excessively attached toner. A doctor roller 14c for removing is provided.

In such a developing section 14, a region where the insulating pattern layer 5 charged to the anode is not formed (the light absorbing layer 4 =
Reversal development in which the charged toner T also charged to the anode adheres to the (image area). That is, the charged toner T charged to the anode is transferred from the liquid toner to the developing roller 1.
4b (connected to the positive electrode), it is conveyed to the vicinity of the electrostatic printing master plate 1. At this time, the conductive layer 3 of the electrostatic printing master plate 1 is grounded, and the insulating pattern layer 5 is connected to the anode. The charged toner T adheres to the non-formed area (light absorbing layer 4 = image area) of the insulating pattern layer 5 due to the repulsion with the insulating pattern layer 5. After the charged toner T is attached to the non-formed area of the insulating pattern layer 5 which is the image area, the excess charged toner T adhering to the area other than the image area is removed by the doctor roller 14c. Then, the development is completed.

When the charged toner T adheres to the image area, the non-image is usually formed by the electrostatic repulsion between the insulating pattern layer 5 charged on the anode and the charged toner T charged on the anode. There is no occurrence of so-called background contamination, in which the charged toner T adheres to the line portion (insulating pattern layer 5).

If the area to which the charged toner T adheres is large, a negative bias voltage may be applied to the conductive layer 3 of the master plate 1 for electrostatic printing.

Then, when the electrostatic printing master plate 1 to which the charged toner T is attached comes into contact with the printing medium 21 with the rotation of the printing cylinder 12, the printing cylinder 21 is moved through the printing medium 21.
Due to the action of the negative charge type charger 15 disposed so as to oppose the toner, the charged toner T adhering on the non-formation area (light absorbing layer 4) of the insulating pattern layer 5 is formed.
Is transferred to the printing medium 21. The transferred charged toner T is
By drying and removing the attached insulating solvent, the insulating solvent is fixed to the printing medium 21 to form an image.

In the electrostatic printing master plate 1 of the present invention, the light absorbing layer 4 (insulating pattern layer 5
(The non-forming region) contains the binder made of the organic-inorganic composite material as described above, so that the affinity of the light absorbing layer 4 for the charged toner T is low, and the light absorbing layer 4 ( The toner is prevented from being deposited on the image portion. Therefore, high-density image formation can be repeatedly and stably performed even in high-speed printing by a wet method. In the above-described example, the electrostatic printing device 11 including the plate cylinder 12 is used, but a planographic type electrostatic printing device or the like may be used.

[0035]

Next, the present invention will be described in more detail with reference to examples.

(Example) First, a polyethylene terephthalate film (Metal Me manufactured by Toray Industries, Inc .;
m)) was prepared as a conductive substrate.

Next, an ink for a light-absorbing layer having the following composition was dispersed on the aluminum-deposited layer of the conductive substrate with a paint shaker, applied by a blade coater and dried to form a light-absorbing layer having a thickness of 2 μm. A layer was formed.

Composition of ink for light-absorbing layer : 40% polyalkylsiloxane alcohol solution: 50 parts by weight (Nippon Synthetic Rubber Co., Ltd. Glaska HP7506) Glasca HPC406H manufactured by Synthetic Rubber Co., Ltd. ・ Carbon black fine particles ・ ・ ・ 20 parts by weight (Ketchin Black EC manufactured by Akzo Holland) ・ Methyl alcohol ・ ・ ・ 25 parts by weight

Next, an insulating layer ink having the following composition was applied on the light absorbing layer by a blade coater and dried to form an insulating layer having a thickness of 2 μm. Composition of ink for insulating layer・ Polystyrene (reagent manufactured by Junsei Chemical Co., Ltd.)… 20 parts by weight ・ Methyl ethyl ketone… 80 parts by weight

Next, a laser (wavelength: 780 nm, output: 300 mW) was image-wise (line width: 10 μm) applied to the insulating layer.
m, line pitch 20 μm). Next, when the insulating layer was wiped with a cloth impregnated with a solvent (Esso's Isopar G), the insulating layer in the laser irradiation area was removed.
An insulating pattern layer patterned into a high-definition image is formed so that the light-absorbing layer is exposed at a line width of 10 μm and a line pitch of 20 μm, and an electrostatic printing master plate having a layer structure shown in FIG. 2 is obtained. Was done.

Using the electrostatic printing master plate manufactured as described above, plain paper (basis weight 70 g / gram) as an object to be printed under the following conditions by an electrostatic printing apparatus having a basic structure as shown in FIG. m ² ). As a result, it corresponds to the insulating pattern layer of the electrostatic printing master plate and has a line width of 10
A high-definition image having a thickness of 20 μm and a line pitch of 20 μm could be formed on plain paper. By repeating this image formation, a high-definition image of 2000 screens could be obtained. When the plate surface of the electrostatic printing master plate after printing 2,000 screens was observed, no accumulation of toner was observed on the exposed light absorbing layer.

Electrostatic printing conditions / Electrification of master plate for electrostatic printing: Anode ・ Liquid toner: Insulating solvent = Isoper-G toner manufactured by Esso Co. = Anode ・ Printing speed: 30 m / min

(Comparative Example) An electrostatic printing master plate was prepared in the same manner as in Example, except that the ink for a light absorbing layer having the following composition was used as the ink for a light absorbing layer. This electrostatic printing master plate had an insulating pattern layer patterned into a high-definition image so that the light-absorbing layer was exposed at a line width of 10 μm and a line pitch of 20 μm.

Composition of ink for light absorbing layer : Cellulose acetate butyrate: 20 parts by weight (CAB381-0.2 manufactured by Eastman Chemical Co.) Carbon fine particles: 20 parts by weight (Ketchin Black EC manufactured by Akzo, the Netherlands) Methyl alcohol: 60 parts by weight

Using the electrostatic printing master plate manufactured as described above, an image was formed on plain paper under the same conditions as in the example. As a result, an image having a line width of 10 μm and a line pitch of 20 μm could be formed on plain paper corresponding to the insulating pattern layer of the electrostatic printing master plate. By repeating this image formation, a high definition image of 100 screens could be obtained. However, the print density decreased from 150 screens,
Observation of the plate surface of the electrostatic printing master plate after printing 200 screens confirmed that toner had accumulated on the exposed light absorbing layer.

[0046]

As described above in detail, according to the present invention, a light-absorbing layer containing a binder made of an organic-inorganic composite material is interposed on at least a conductive layer of a conductive substrate having a conductive layer on a surface layer. Since the master plate is an electrostatic printing master plate with an insulating pattern layer formed on it, the organic-inorganic composite material contained as a binder in the light-absorbing layer lowers the affinity of the light-absorbing layer with respect to the toner. Even if it is performed, the toner is prevented from being deposited on the light absorbing layer, and high-density image formation can be performed stably in high-speed printing by a wet method.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an embodiment of the electrostatic printing master plate of the present invention.

FIG. 2 is a process chart showing an example of a method for manufacturing an electrostatic printing master plate of the present invention.

FIG. 3 is a schematic configuration diagram of an electrostatic printing apparatus for describing an example of electrostatic printing using the electrostatic printing master plate of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Electrostatic printing master plate 2 ... Conductive base material 3 ... Conductive layer 4 ... Light absorbing layer 5 ... Insulating pattern layer 5 '... Insulating layer

Claims (1)

[Claims] 1. A light-emitting device comprising: a conductive base material having a conductive layer at least on a surface portion; and an insulating pattern layer formed on the conductive layer of the conductive base via a light-absorbing layer. The electrostatic printing master plate, wherein the absorbing layer contains a binder made of an organic-inorganic composite material.