JP2001001662A - Offset printing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an offset printing method which satisfies fitness for simplified plate- making using no developer, printed image quality based on the distinguishability of an image area from a non-image area of a printed face, and sufficient plate durability. SOLUTION: The surface of an original plate for printing, which has an image forming layer composed of a metallic oxide having characteristics that the surface thereof shows hydrophilicity by being irradiated with light and/or a metallic oxide having characteristics of the development of high-temperature hydrophilicity, is processed to be hydrophobic. By irradiating this surface with light imagerially or by heating the surface at a temperature required for developing the high-temperature hydrophilicity imagerially, the distribution of hydrophilic and hydrophobic image patterns is allowed to be formed. An aqueous solution for the non-electrolyte plating, which contains a water-soluble metallic compound and a reducible compound and which is so prepared that an oxidation potential of the reducible compound is baser (lower potential) than a reduction potential of the water-soluble metallic compound, is brought into contact with the surface of the original plate for printing, which has the image pattern distribution. Thereby, a metallic thin layer is allowed to be formed in the image pattern by the non-electrolyte plating in a hydrophilic region on the original plate for printing, which has nuclei for precipitation of metal on the surface thereof, thus making a printing plate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to the field of general light printing,
In particular, the present invention relates to offset printing, and particularly to a novel offset printing method and a printing original plate that can easily produce a printing plate. In particular, the present invention relates to an offset printing method and an original plate for printing in which simplicity of a plate making process and printing durability are compatible, and in which printing smear is reduced.

[0002]

2. Description of the Related Art The offset printing method has been used particularly commonly because of a simple printing plate manufacturing process among many printing methods, and is the main printing method at present. This printing technique is based on the immiscibility of oil and water, with the image areas selectively retaining oily material or ink and the non-image areas selectively retaining fountain solution. Therefore, when the surface to be printed is brought into direct contact with the surface to be printed or indirectly through an intermediate called a blanket, the ink in the image area is transferred and printing is performed.

The main method of offset printing is a PS plate having an aluminum substrate as a support and a diazo photosensitive layer provided thereon. In the PS plate, the surface of the aluminum substrate, which is the support, is subjected to graining, anodic oxidation, and other treatments to enhance the ink receiving capacity of the image area and the ink repulsion of the non-image area, thereby improving the printing durability. Then, the printing surface is made finer, and a printing image is formed on the surface. Therefore, offset printing has been provided with characteristics such as printing durability and high definition of a printing surface in addition to simplicity.

While the use of the offset printing method has been widespread and spread in the general printing field due to higher definition, further simplification of the offset printing method has been demanded, and many simple printing methods have been proposed.

[0005] From the above background, there has been developed a method of manufacturing a simple printing plate in which a developing step using an alkali developing solution after image exposure is omitted. In the technical field of this simple printing plate, which is also called an unprocessed printing plate because the development step can be omitted, the image formation by thermal destruction of the irradiated portion on the image recording surface mainly by imagewise exposure, Image formation by lipophilicity and lipophilicity of the irradiated part are also based on various principles such as photo-mode curing, changes in surface properties due to photolysis of diazo compounds, and heat mode fusion thermal transfer of image areas. Proposed.

As described above, many simple printing methods which do not require a developing solution for plate making have been devised, but the difference between the lipophilic region and the hydrophilic region is insufficient, and therefore the image quality of the printed image is poor. Is poor, the resolution is poor, it is difficult to obtain a printed screen with excellent sharpness, the mechanical strength of the image surface is insufficient and it is easily scratched, and the simplicity is impaired by providing a protective film on the contrary. thing,
It is accompanied by at least one of the drawbacks, such as insufficient durability to withstand long-time printing, and indicates that simply eliminating the alkali development step does not involve practicality. In spite of the above-mentioned many improvements, a strong demand for a printing plate preparation method that has various characteristics required for printing and can easily produce a printing plate has not been sufficiently satisfied.

As one of the technical developments of the above-mentioned non-processing type printing plate, a printing plate manufacturing method utilizing the fact that zirconia ceramics are made hydrophilic by light irradiation is disclosed in JP-A-9-16.
No. 9098. However, the light sensitivity of zirconia is insufficient, and the discriminability between the image area and the non-image area is insufficient due to the insufficient light conversion effect from hydrophobicity to hydrophilicity, and especially printing durability is required. However, it has not sufficiently responded to the demands of the market, and has not solved the problem of simplification due to no processing.

[0008]

Under such circumstances, the present inventor has found a phenomenon in which the degree of hydrophobicity or hydrophilicity of the surface is changed by the action of light or by the action of heat. We have devised a printing method with improved simplicity that does not require development using. However, there is a strong demand in the market for a printing method that satisfies both simplicity, discrimination between an image portion and a non-image portion, and furthermore, printing durability. In particular, further improvement in printing durability is desired.

[0009] In view of the above circumstances, the problem to be solved by the present invention is to provide a simple plate making suitability without using a developing solution and a sufficient print quality supported by the discrimination between the image area and the non-image area on the printing surface. An object of the present invention is to provide an offset printing method satisfying both printing durability. Another object of the present invention is to provide an offset printing method capable of repeatedly reusing a printing plate.

[0010]

SUMMARY OF THE INVENTION The present inventor has further developed the discrimination and printing durability of the above simple printing method utilizing the phenomenon that the degree of hydrophobicity or hydrophilicity of the surface is changed by the action of light or heat. The means of improvement were studied diligently. As a result, the object of the present invention is to succeed in reinforcing the electrodeposited area of the plate surface by performing electrodeposition of the metal film only on the imagewise hydrophilic area and improving both simplicity, discrimination and printing durability. Has been found to be satisfied.

According to the present invention, a printing plate having on its surface a metal oxide having a property of making the surface hydrophilic by light irradiation and / or a metal oxide having a high-temperature hydrophilicity developing property is brought into contact with an organic compound. Or, by heating to the temperature at which hydrophobicity is exhibited, the surface of the original plate is rendered hydrophobic, and then the surface is irradiated with light imagewise or heated imagewise at a high temperature at which hydrophilicity is exhibited, or the irradiated portion or Change the heating section to hydrophilic, form an image-like distribution of hydrophobic areas and hydrophilic areas,
A water-soluble metal compound and a reducing compound are contained on a printing plate having the image-like distribution, and the oxidation potential of the reducing compound is adjusted to be lower (lower potential) than the reduction potential of the water-soluble metal compound. The resulting aqueous solution for electroless plating is brought into contact with the aqueous solution for electroless plating, and a thin metal layer is formed imagewise by electroless plating on the hydrophilic region on the printing original plate and the hydrophilic region having metal deposition nuclei on the surface. Further, the hydrophobic area is subjected to a hydrophilic treatment, and the printing original plate is brought into contact with ink to form a printing surface receiving the ink in the area having the thin metal layer, and printing is performed. This is a characteristic offset printing method.

Preferred embodiments of the present invention are as follows. 1． An offset printing method, comprising: after forming an image-like distribution, providing a metal precipitation nucleus on a printing original plate in a hydrophilic region, and then bringing the aqueous solution for electroless plating into contact with a substrate. 2. The printing plate has photocatalytic activity, and after making the surface of the printing plate hydrophobic, imagewise irradiation with active light is performed to form an image-like hydrophilic region on the surface of the printing plate. Offset printing method characterized by the above-mentioned.

3. The temperature at which the surface of the printing plate becomes hydrophobic
An offset printing method at 0 to 250 [deg.] C., wherein the surface of the printing original plate is heated at a temperature for expressing hydrophobicity to make the surface hydrophobic.

4. The surface of the printing plate is the third in the periodic table
An offset printing method characterized by comprising at least one of the group consisting of oxides of metals selected from elements other than Group 0 and Group VIIA (halogen element), which belong to ~ 6 cycles.

[0015] 5. The surface of the printing plate is made of TiO_Two, RTiO
_Three(R is an alkaline earth metal atom), AB_2-xC_xD_3-xE_xO
_Ten(A is a hydrogen atom or an alkali metal atom, B is an alkali
Earth metal or lead, C is rare earth, D is periodic
A metal atom belonging to the 5A group element in the table, E is also a 4A group element
X represents an arbitrary numerical value from 0 to 2
), SnO_Two, GeO_Two, SiO_Two, Bi_TwoO_Three, A
l_TwoO_Three, ZnO and FeO _x(X = 1 to 1.5)
Constituted by at least one of the selected metal oxides
Offset printing method characterized in that:

6. Hydrophobicization of the printing original plate surface is performed by exposing the printing original plate to an atmosphere containing an organic compound gas, applying or spraying a liquid organic compound or a liquid containing an organic compound onto the printing original plate, and applying a liquid organic compound to the printing original plate or An offset printing method, which is performed by immersion in an organic compound-containing liquid.

[7] An offset printing method, wherein the organic compound is an organic compound having a vapor pressure of at least 10 mmHg at a temperature of 20 ° C.

[8] An offset printing method, characterized in that the organic compound is an organic compound that dissolves in at least 5 wt% in at least one organic solvent selected from ethanol, acetone, benzol and 2,2,4-trimethylpentane at a temperature of 20 ° C.

9. An offset printing method, characterized in that the means for making the hydrophobic area on the surface of the printing original plate hydrophilic before printing is a means selected from irradiation with active light and washing of the hydrophobic area.

[10] An offset printing method, wherein a printing plate is manufactured from the printing plate and printing is performed with the printing plate mounted on a printing press.

In the present invention, the term “metal oxide having a property that its surface becomes hydrophilic by light irradiation” (hereinafter, also referred to as “metal oxide having photocatalytic ability”) is defined as the light irradiation. Light of a specific wavelength that changes the surface of a metal oxide having photocatalytic activity to hydrophilicity or light containing the same is irradiated, and a metal oxide having photocatalytic activity is a substance such as titanium oxide, for example. Is a substance that changes optical properties such that when the surface is irradiated with the light, the surface changes to hydrophilic. Further, light of a specific wavelength that causes such a change in optical properties is called “active light”.

On the other hand, "a metal oxide having a high-temperature hydrophilicity-developing property" means that it becomes hydrophilic when heated to a certain temperature or more, and this hydrophilicity has a hysteretic effect, and the hydrophilicity of the surface becomes low even when the temperature is returned to normal temperature. It is a metal oxide that has some lasting properties. The temperature at which the hydrophilicity appears is called "high-temperature hydrophilicity-expressing temperature". Among metal oxides, in addition to those whose clean surfaces are inherently hydrophobic to varying degrees, even when the surfaces are inherently hydrophilic, the "hydrophobic expression temperature"
The present inventor has found that when heated to a temperature referred to as, there is a substance that changes from hydrophilic to hydrophobic.
Among these metal oxides, metal oxides whose hydrophobic surfaces became hydrophilic again when further heated above the temperature at which hydrophobicity was developed were observed. Some "metal oxides having high-temperature hydrophilicity-expressing properties" exhibit hydrophobicity at such intermediate heating temperatures.

According to the present invention, the metal oxide to be present on the surface of the printing plate has at least a photocatalytic ability or a high-temperature hydrophilicity developing property. can do. In the specification of the present application, when such a metal oxide is referred to generically, it is also referred to as a “metal oxide having hydrophilicity developing properties”. The present invention has been made by making use of the further finding that, in addition to the above-mentioned properties, the surface of a metal oxide having the above-mentioned hydrophilicity-expressing properties in a hydrophilic state at room temperature becomes hydrophobic when it comes into contact with an organic compound. is there. Further, an image-like distribution of a hydrophobic region and a hydrophilic region is formed on the original plate, and a water-soluble metal compound and a reducing compound are contained on this surface, and the oxidation potential of the reducing compound is reduced by the reduction potential of the water-soluble metal compound. When electroless plating is performed by contacting an aqueous solution for electroless plating prepared to be less basic (low potential), a plating reaction occurs selectively and effectively in a hydrophilic region having metal deposition nuclei on the surface. It has also been found that a thin metal layer is formed in this region. The printing method of the present invention is a novel invention achieved by utilizing the physical properties and phenomena described above in combination.

The printing method of the present invention comprises subjecting the above-mentioned "metal oxide having a hydrophilic property" to an original plate and performing the following steps. The first step is to make the surface of the original plate of the above substance hydrophobic. As a method of making the surface hydrophobic, there are a method of making an organic compound act and a method of heat treatment. The former involves exposing the surface of the original plate to vapors of organic compounds, spraying or applying an organic compound in a liquid or solution state to the surface of the original plate, or immersing the original plate in a liquid organic compound. Done. The latter is a means that can be applied when the original plate material is a substance exhibiting hydrophobicity that becomes hydrophobic by moderate heating, and the surface thereof can be made hydrophobic by heating to the temperature at which hydrophobicity is exhibited.

The second step is a step of forming an imagewise hydrophilic region on the surface of the original plate which has been rendered hydrophobic. At this stage, in the case of a metal oxide having a photocatalytic ability, actinic light is irradiated imagewise, and in the case of a metal oxide having a high-temperature hydrophilicity developing characteristic, it is heated imagewise to perform heating or irradiation. By rendering the received portion hydrophilic, an image-like distribution of hydrophilic and hydrophobic regions is formed on its surface.

The third step is a step of imagewise providing a thin metal layer in the hydrophilic region on the printing original plate in which the imagewise distribution of the hydrophilic region and the hydrophobic region has been formed. At this stage, an aqueous solution for electroless plating is brought into direct contact with the printing original plate. Due to this contact, electroless plating occurs in the image-like hydrophilic region having metal precipitation nuclei, but this electroless plating does not occur in the hydrophobic region. Accordingly, the metal from the water-soluble metal compound of the aqueous solution for electroless plating is deposited on the printing original plate in the hydrophilic image-like region, and an image-like distribution of the thin metal layer is obtained. The metal precipitation nuclei in the hydrophilic region are preferably formed after the image-like distribution is formed and before the treatment by the electroless plating. There is no particular limitation as long as precipitation nuclei are provided, and they may be provided in advance on the entire surface of the printing original plate before the first step within a range that does not adversely affect print quality.

The fourth step is an operation for making the hydrophobic region hydrophilic by applying a hydrophilic treatment to the hydrophobic region where electroless plating has not occurred. , Irradiation with active light, heating to a high-temperature hydrophilicity-expressing temperature, and the like. Fifth
The stage is a printing process. By contacting the printing master with the ink, the image-wise distributed hydrophobic regions receive the printing ink and form a printing surface. By performing the above series of operations, a printing plate is made from a printing original plate, and printing is performed using the printing plate. In the present invention,
It is possible to repeat the reproduction of the printing original plate for removing the ink of the printing plate after the required printing and removing the electroless plated metal thin layer.

In the second step, the surface of the metal having the property of exhibiting high-temperature hydrophilicity is changed from hydrophobic to hydrophilic by heating at the temperature at which high-temperature hydrophilicity is exhibited. Due to the hysteresis effect, the hydrophilicity is maintained for a practically sufficient time. Therefore, the effective hydrophilic region on the surface, which has sufficiently promoted the hydrophobicity by contact with the organic compound, is maintained for a practical period of time, so that the above-described third-stage electroless plating is applied to the hydrophilic region. It occurs effectively and forms a thin metal layer. This thin metal layer is more hydrophobic than the surface area of the original printing plate on which the thin metal layer was not formed (excluding the surface of the original printing plate if it was made hydrophobic with an organic compound). By performing the hydrophilization treatment on the hydrophobic region which has not been made, the ink can be applied to the thin metal layer and printing can be performed. According to the present invention, a direct plate making / printing method that does not require development by utilizing a change in the physical properties of hydrophobic to hydrophilic properties of the surface of an original printing plate as described above is possible. Moreover, in addition to the simplicity of direct plate making, it is a feature of the present invention that the printing durability can be improved by reinforcing the plate surface with a thin metal layer.

[0029]

(Printing plate)

(Original Plate Material) First, an original plate material that can be used in the present invention will be described. The “metal oxide having photocatalytic ability” that becomes hydrophilic by light irradiation used in the present invention is also found in ceramics and semiconductors. Ceramics with photocatalytic properties are composed of composite metal oxides.Most semiconductors with photocatalytic properties are genuine semiconductors, whose base order and conductor are close, and pseudo semiconductors such as vanadium oxide and copper oxide, which depend on impurity levels. And is seen in both. Since these ceramics and semiconductors are the same as other metal oxides having photocatalytic ability on the photocatalytic ability utilized by the present invention, they will be described below by including them in "metal oxide having photocatalytic ability". .

The metal oxide having a preferable photocatalytic activity is
Belongs to the third to sixth periods of the periodic table, and 0 and VII
It is constituted by at least one of the group consisting of oxides of metals selected from elements other than group A (halogen elements). Above all, TiO ₂ , RTiO ₃ (R is an alkaline earth metal atom), AB _{2- x} C _x D _3-x E _x O ₁₀ (A is a hydrogen atom or an alkali metal atom, B is an alkaline earth metal atom Or a lead atom, C is a rare earth atom, D is a metal atom belonging to the group 5A element of the periodic table, E is a metal atom also belonging to the group 4A element, and x is any numerical value from 0 to 2), Sn
A metal oxide selected from O ₂ , Bi ₂ O ₃ , ZnO and Fe ₂ O ₃ is preferred.

These metal oxides are found in various forms of metal oxides, and may be single metal oxides or composite oxides. In the latter case, solid solutions, mixed crystals, polycrystals, A mixture having a crystal characteristic, an amorphous solid solution, and a metal oxide microcrystal has this characteristic.

Next, the "metal oxide having high-temperature hydrophilicity-developing property" which becomes hydrophilic when heated at a high temperature and exhibits a hysteresis phenomenon will be described. This substance may be a metal oxide which has both photocatalytic ability and high-temperature hydrophilicity developing properties. Preferred metal oxides exhibiting high-temperature hydrophilicity are metals belonging to the third to sixth periods of the periodic table and selected from elements other than group 0 and group VIIA (halogen element), and oxides of the metals. At least one of the group consisting of

Also, it has favorable high-temperature hydrophilicity developing properties.
Metal oxide is TiO_Two, RTiO _Three(R is alkaline earth
Metal atom), AB_2-xC_xD_3-xE_xO_Ten(A, B, C, D,
The meaning of each symbol of E and x is as described above.
Yes), SnO_Two, SiO _Two, GeO_Two, Bi_TwoO_Three,
Al_TwoO_Three, ZnO and FeO_x(X = 1.0-1.5)
A metal oxide selected from the group consisting of:

Most of the metal oxides having a high-temperature hydrophilicity developing property have a property of exhibiting hydrophobicity by moderate heating lower than the high-temperature hydrophilicity developing temperature as described above. Instead of contacting with an organic compound, moderate heating may be performed. The hydrophobicity development temperature varies depending on the substance, but is usually 50 to 250 ° C.

The metal oxide having a hydrophilic property that can be used in the present invention must not be excessively dissolved in fountain solution when used as a printing plate. 10 for 100 ml of water
mg or less, preferably 5 mg or less, more preferably 1 m
g or less.

The metal oxide having the property of exhibiting hydrophilicity has been outlined above, and each preferred metal oxide will be further described. Among the metal oxides, titanium oxide and zinc oxide are preferable, and these will be described first. Any of these can be used as the printing plate material of the present invention. In particular, titanium oxide is preferable in terms of sensitivity (that is, sensitivity of surface property to light change). As the titanium oxide, one made by any known method such as sulfuric acid heating and sintering of ilmenite or titanium slag, or heat chlorination followed by oxygen oxidation can be used. Alternatively, as described later, a method of forming an oxide film by vacuum evaporation at the stage of producing a printing plate using titanium metal can also be used.

In order to provide a layer containing titanium oxide or zinc oxide on the surface of an original plate, for example, a method of applying a dispersion of titanium oxide microcrystals or zinc oxide microcrystals on a printing plate original plate was applied. A method of reducing or removing the binder by baking afterwards, a method of providing a titanium oxide (or zinc oxide) film on a printing original plate by a method such as vapor deposition, sputtering, ion plating, or CVD, for example, a titanium organic compound such as titanium butoxide Can be applied to the original plate, followed by baking and oxidation to form a titanium oxide layer, or any other known method. In the present invention, a titanium oxide layer formed by vacuum deposition or sputtering is particularly preferred.

The above or the method of applying the titanium oxide microcrystals is, specifically, a method of applying an amorphous titanium oxide microcrystal dispersion, followed by firing to form an anatase or rutile type crystal titanium oxide layer. A method of applying a mixed dispersion of titanium oxide and silicon oxide to form a surface layer, and a method of applying a mixture of titanium oxide and organosiloxane to obtain a titanium oxide layer bonded to a support through a siloxane bond A method of dispersing and applying a polymer binder capable of coexisting with an oxide in an oxide layer, followed by baking to remove an organic component. As the binder for the oxide fine particles, a polymer having dispersibility with respect to the titanium oxide fine particles and capable of being removed by firing at a relatively low temperature can be used. Examples of preferred binders include polyalkylene such as polyethylene, polybutadiene, polyacrylate, polymethacrylate, polyvinyl acetate, polyvinyl formate, polyethylene terephthalate, polyethylene naphthalate, polyvinyl alcohol, partially saponified polyvinyl alcohol, polystyrene, and the like. Is preferred, and these resins may be used as a mixture.

For performing the above-mentioned vacuum deposition of titanium oxide,
Is usually used as a heat source for evaporation heating in vacuum evaporation equipment.
And place it in a vacuum of 10^-Five-10^-810 Torr total gas pressure^-2
-10 ^-FiveTorr, oxygen partial pressure ratio 30-90%
While evaporating titanium metal, oxidation surface is oxidized
A deposited thin film of titanium is formed. Also, sputtering
In the case of using a titanium metal tar
Set get and Ar / O_Two The ratio is 60/40 (mol
Ratio) so that the gas pressure is 5 × 10^-3Adjusted to Torr
Then, RF power of 200 W was input and sputtering was performed.
To form a titanium oxide thin film on the substrate.

On the other hand, when a zinc oxide layer is used in the present invention, the zinc oxide layer can be formed by any known method. In particular, a method of forming an oxide film by electrolytically oxidizing the surface of a metal zinc plate and a method of forming a zinc oxide film by vacuum deposition, sputtering, ion plating, CVD, or the like are preferable. A method for forming an oxide film by depositing metal zinc in the presence of oxygen gas in the same manner as the above-described deposition of titanium oxide, or a method for forming a zinc metal film in the absence of oxygen, In the temperature of about 70
A method of raising the temperature to 0 ° C and oxidizing can be used. In addition, it can be obtained by heating a coated layer of zinc oxalate or a thin layer of zinc selenide in an oxidizing gas stream.

The thickness of the deposited film is preferably from 1 to 100,000 angstroms, and preferably from 10 to 10,000 angstroms, in any case of the titanium oxide layer and the zinc oxide layer. More preferably, the thickness is set to 3000 angstroms or less to prevent distortion of light interference. Further, it is convenient that the thickness is 50 Å or more in order to sufficiently exhibit the photoactivation effect.

Although any crystal form of titanium oxide can be used, anatase type is particularly preferred because of its high sensitivity. It is well known that anatase-type crystals can be obtained by selecting firing conditions in the process of firing titanium oxide. In this case, amorphous titanium oxide or rutile-type titanium oxide may coexist, but those containing 40% or more, preferably 60% or more of anatase-type crystals are preferable for the above reason. The volume ratio of titanium oxide or zinc oxide in the layer mainly containing titanium oxide or zinc oxide is 30 to 100%, preferably 50 to 100%.
% Or more is preferably occupied by the oxide, more preferably a continuous layer of oxide, ie substantially 100%.
However, since the surface hydrophilicity / lipophilicity change characteristics are not affected by the remarkable purity as when zinc oxide is used in the electrophotographic photosensitive layer, a material having a purity close to 100% (for example, 98%) is further purified. There is no need to convert. That is, it can be understood from the fact that the physical properties used in the present invention are the properties of changing the hydrophilic / lipophilic properties of the membrane surface, which are not related to the conductivity, that is, the properties of changing the properties of the interface.

However, it may be effective to dope a certain metal in order to enhance the property of changing the hydrophilicity of the surface by the action of heat. For this purpose, doping of a metal having a low ionization tendency is suitable. And
It is preferable to dope Pt, Pd, Au, Ag, Cu, Ni, Fe, Co or Cr. Further, a plurality of these preferable metals may be doped. Also in the case where doping is performed, the injection amount is 5 mol% or less based on the metal components in zinc oxide and titanium oxide.

On the other hand, if the volume ratio is low, the hydrophilicity /
The sensitivity of the lipophilic thermal response behavior decreases. Therefore,
The volume ratio of the oxide in the layer is desirably 30% or more, particularly preferably substantially 100%.

Next, another compound that can be used in the present invention, that is, a metal titanate represented by the general formula RTiO3 will be described. In the general formula RTiO3, R is a metal atom belonging to an alkaline earth element of the periodic table such as magnesium, calcium, strontium, barium, beryllium, and strontium and barium are particularly preferred. Also, two or more alkaline earth metal atoms can coexist as long as the total thereof is stoichiometrically consistent with the above formula.

Next, the compound represented by the general formula AB _2-x C _x D _3-x E _x O ₁₀ will be described. In this general formula, A
Is a hydrogen atom and a monovalent atom selected from alkali metal atoms such as sodium, potassium, rubidium, cesium, and lithium. Is also good. B is an alkaline earth metal atom or a lead atom as defined above for R,
Similarly, two or more atoms may coexist as long as they are stoichiometrically matched. C is a rare earth atom, preferably scandium and yttrium and lanthanum, cerium,
It is an atom belonging to a lanthanoid element such as praseodymium, neodymium, holmium, europium, gadolinium, terbium, thulium, ytterbium, lutetium, and two or more of these atoms as long as their total is stoichiometrically consistent with the above formula. May coexist. D is one or more elements selected from Group 5A elements of the periodic table, and includes vanadium, niobium, and tantalum. Further, as long as the stoichiometric relationship is satisfied, two or more kinds of 5A group metal atoms may coexist. E is a metal atom belonging to the Group 4A element such as titanium, zirconium and hafnium;
More than one group 4A metal atom may coexist. x is 0
2 represents any numerical value.

RTiO ₃ , a general formula AB _2-x C _x D _3-x E _x O
_The above compound represented by ₁₀ , SnO ₂ , Bi ₂ O ₃ , F
in any of the thin film formation of eO _n (x = 1~1.5) iron oxide compounds represented by, it is out using said method of providing a titanium oxide and zinc oxide. That is, a method of applying a dispersion of fine particles of metal oxide on a printing plate precursor, a method of applying and baking to reduce or remove the binder, and applying various types of vacuum to the printing plate precursor by applying the above-mentioned oxide to the printing plate. A method of forming a film by a thin film method, for example, after applying an organic compound such as an alcoholate of a metal element onto a base plate,
Any known method can be used, such as a method of hydrolyzing and further performing calcination oxidation to form a metal thin film having an appropriate thickness, and a method of heating and spraying an aqueous solution of a hydrochloride or a nitrate of the above metal element.

For example, in order to apply the barium titanate fine particles by the application method described above, a method of applying a mixed dispersion of barium titanate and silicon to form a surface layer, barium titanate and organopolysiloxane Alternatively, there is a method of applying a mixture with the monomer. Further, as described in the section of titanium oxide, the oxide layer can be formed by dispersing and applying a polymer binder which can coexist with the oxide in the oxide layer, followed by firing. Examples of preferred polymers as the binder for the oxide fine particles are the same as those described in the section of the titanium oxide layer. By this method, a thin film of magnesium titanate, calcium titanate, strontium titanate or an intermolecular compound or a mixture thereof can be similarly formed in addition to barium titanate.

Similarly, CsLa ₂ NbTi ₂ O ₁₀ fine particles can be coated by the above-described coating method. CsLa ₂ NbTi ₂ O ₁₀ fine particles correspond to the stoichiometry of Cs ₂ CO ₃ , La ₂ O ₃ , NbO ₅ , TiO ₂
Is pulverized in a mortar, placed in a platinum crucible, baked at 130 ° C. for 5 hours, cooled, and then placed in a mortar and pulverized to fine particles of several microns or less. This CsLa ₂ NbTi ₂
The O ₁₀ fine particles dispersed in a binder as with barium titanate of the, to form a thin film by coating. This method is not limited to CsLa ₂ NbTi ₂ O ₁₀ type fine particles,
_{1.5 La 0.5 Nb 2. 5 Ti 0.5} O 10, HLa 2 NbTi 2 O 10
This applies to AB _2-x C _x D _3-x E _x O ₁₀ (0 ≦ x ≦ 2).

As a method for forming a metal oxide layer having a hydrophilic property by using the above-mentioned vacuum thin film forming method, a sputtering method or a vacuum thin film forming method is generally used. In the sputtering method, a single or composite oxide target is prepared in advance. For example, a barium titanate crystal thin film can be obtained by performing RF sputtering in an argon / oxygen mixed atmosphere while maintaining the temperature of the support for the deposited film at 450 ° C. or higher using a barium titanate target. For controlling the crystallinity, post-annealing may be performed at 300 to 900 ° C. as necessary.
In this method, a thin film can be formed on the aforementioned RTiO ₃ (R is an alkaline earth metal atom) and other metal oxides by adjusting the substrate temperature optimal for controlling the crystal in the same manner. For example, when a tin oxide thin film is provided, a thin film of the tin oxide crystal for the purpose is obtained by performing RF sputtering in a mixed atmosphere having a substrate temperature of 120 ° C. and an argon / oxygen ratio of 50/50.

Method using the above metal alcoholate
Also, the desired thin film can be formed without using a binder
Is the way. To form a barium titanate thin film
Mixed alcohol of lium ethoxide and titanium butoxide
Solution on the surface with SiO_TwoOn a silicon substrate with
Cloth and after hydrolyzing the surface, to 200 ° C or more
Can be heated to form barium titanate thin film
It is. The method of this method is also similar to the other RTiO described above._Three(R is
Alkaline earth metal atom), AB_2-xC_xD_3-xE_xO_Ten(A,
B, C, D, and E respectively represent the contents of the above definition),
SnO_Two, SiO _Two, Bi_TwoO_ThreeAnd FeO_x(X = 1 to
1.5) Application to thin film formation of iron oxide-based compounds
can do.

The method for forming a metal oxide thin film as described above can also form a binder-free thin film. To form a thin film of SnO _2, a thin film can be formed by spraying a hydrochloric acid aqueous solution of SnCl ₄ onto the surface of quartz or crystalline glass heated to 200 ° C. or higher. In this method, in addition to the SnO ₂ thin film, RTiO ₃ (R is an alkaline earth metal atom), AB _2-x C _x D _3-x E _x O ₁₀ (A,
B, C, D, and E respectively represent the contents of the above definition),
The present invention can be applied to the formation of any thin film of an iron oxide-based compound represented by Bi ₂ O ₃ and FeO _x (x = 1 to 1.5).

In any of the above cases, the thickness of the metal oxide thin film is preferably 1 to 100,000 angstroms, and more preferably 10 to 10,000 angstroms. More preferably, the thickness is set to 3000 angstroms or less to prevent distortion of light interference. Further, it is convenient that the thickness is 50 Å or more in order to sufficiently exhibit the photoactivation effect.

In the thin layer of the metal oxide having the photocatalytic ability when the binder is used, the volume ratio of the metal oxide is 50 to 100%, preferably 90% or more, More preferably, it is a continuous layer of oxide, that is, substantially 100%.

In addition, ZnO, TiO ₂ , SnO ₂ ,
Iron oxide-based compounds represented by Al ₂ O ₃ and FeO _x (x = 1 to 1.5) can also be obtained by anodizing the surface of each metal plate. Especially ZnO, TiO ₂ , A
l ₂ O ₃ is easily obtained by anodic oxidation as a supported metal oxide film having a photocatalytic activity. The method of anodizing is described in detail in, for example, JP-A-6-35174, pages 3-5, the method cited therein, the method described in JP-A-52-37104, and The anodizing method of the aluminum support for a printing plate of the present invention is carried out by a known appropriate method such as the method described below, or a method analogous thereto. When the raw material is prepared by anodic oxidation, the thickness of the oxide film may be the above-mentioned thickness, but may be even greater, and is used at 2.0 μm or less, preferably 1.0 μm or less.

The description of the metal oxide having the property of exhibiting hydrophilicity used in the present invention is completed above, and then, the form of a printing plate carrying these materials is described.

(Form of Printing Plate) Various forms can be used for the printing plate according to the present invention. For example, a thin layer of a metal oxide having a hydrophilic property is directly provided on the surface of a substrate of a plate cylinder of a printing press by vapor deposition, immersion or application, or a metal oxide having a hydrophilic property is carried. Or a printing plate obtained by winding a thin plate of a metal oxide having a hydrophilicity developing property without a support around a substrate of a plate cylinder. Of course, in addition to the above-described form of making a plate on a plate cylinder, a form in which the plate is made may be mounted on a rotary or flatbed printing press, as is generally performed.

When a metal oxide having a hydrophilic property is provided on a support, the support used is a plate which is dimensionally stable, and may be an aluminum plate, a SUS steel plate,
A metal plate such as a nickel plate and a copper plate is preferable, and it is particularly preferable to use a flexible metal plate. Further, a flexible plastic support such as polyesters and cellulose esters can also be used.
An oxide layer may be provided on a support such as waterproofed paper, polyethylene laminated paper, or impregnated paper, and it may be used as a printing plate.

Specifically, paper, paper laminated with a plastic sheet (eg, a sheet of polyethylene terephthalate, polyimide, etc.), a metal plate (eg, aluminum, zinc, copper, stainless steel, etc.), plastic film (eg, Cellulose acetate, cellulose triacetate,
Cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyimide, polystyrene, polycarbonate, polyvinyl acetal, etc.), and paper or a plastic film on which a metal as described above is laminated or evaporated.

A preferred support is a polyester film, a polyimide film, aluminum or a SUS plate which is hardly corroded on a printing plate. Among them, an aluminum plate which has good dimensional stability and is relatively inexpensive, Polyimide films that are highly stable to operation are particularly preferred.

A preferred polyimide film is a polyimide resin film obtained by polymerizing pyromellitic anhydride and m-phenylenediamine and then performing cyclic imidization.
This film is commercially available (for example, “Kapton” manufactured by Dupont Toray) can be mentioned.

Suitable aluminum plates are a pure aluminum plate and an alloy plate containing aluminum as a main component and a trace amount of a different element, and may be a plastic film on which aluminum is laminated or vapor-deposited. The foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of the foreign element in the alloy is at most 10% by weight or less. Particularly preferred aluminum in the present invention is pure aluminum. However, completely pure aluminum is difficult to produce due to refining technology, and therefore may contain a slightly different element. As described above, the composition of the aluminum plate applied to the present invention is not specified, and an aluminum plate of a conventionally known and used material can be appropriately used. The thickness of the metal support used in the present invention is about 0.1 mm to 0.6 mm, preferably 0.15 mm to 0.4 mm, particularly preferably 0.2 mm
The thickness of other supports such as plastic and processed paper is about 0.1 mm to 2.0 mm, preferably 0.2 mm to 1.0 mm.

When an aluminum support is used, the surface is preferably roughened. In this case, if necessary, a degreasing treatment with a surfactant, an organic solvent, an aqueous solution for electroless plating, or the like is performed to remove rolling oil on the surface prior to roughening. The surface roughening treatment of the aluminum plate is performed by various methods.
For example, it is performed by a method of mechanically roughening the surface, a method of electrochemically dissolving and roughening the surface, and a method of chemically selectively dissolving the surface. Known mechanical methods such as a ball polishing method, a brush polishing method, a blast polishing method, and a buff polishing method can be used as the mechanical method. In addition, as the electrochemical surface roughening method, a known method such as performing an alternating or direct current in a hydrochloric acid or nitric acid electrolyte can be used. Further, the roughened aluminum plate is subjected to an alkali etching treatment and a neutralization treatment as necessary, and then subjected to an anodic oxidation treatment, if necessary, in order to increase the water retention and abrasion resistance of the surface. The concentration of the anodic oxidation electrolyte is appropriately determined depending on the type of the electrolyte.

The anodizing treatment conditions vary depending on the electrolyte to be used and cannot be specified unconditionally.
It is appropriate that the current density is 5 to 60 A / dm ² , the voltage is 1 to 100 V, and the electrolysis time is 10 seconds to 5 minutes. If the amount of the anodic oxide film is less than 1.0 g / m ² , the printing durability is insufficient or the non-image area of the lithographic printing plate is easily scratched, and the ink adheres to the scratched area during printing. So-called "scratch dirt"
Tends to occur.

In order to enhance the high-temperature hydrophilicity developing characteristics of the printing original plate, it is effective to provide a heat insulating layer below the image forming layer. When drawing by light-to-heat conversion is performed, a light-to-heat conversion layer may be provided as a lower layer when the functional surface is transparent to the light.

The material, the support, and the structure of the printing original plate using the metal oxide having a hydrophilic property used in the printing method of the present invention have been described above. Next, a plate making method using this printing original plate will be described in the order of the first to fifth operations.

[Plate Making Step] (Entire Hydrophobicity) The first step is to make the metal oxide having the property of exhibiting hydrophilicity entirely hydrophobic as described above. The entire surface is rendered hydrophobic by contacting it with an organic compound as described above, or, in the case of a substance having a property of changing to hydrophobic by heating, by heating the substance to a hydrophobic expression temperature. . In the latter case, it has been found that the presence of an organic compound promotes hydrophobicity. Therefore, it is also preferable to contact the organic compound at a temperature at which hydrophobicity is developed. Further, as described above, the method of bringing the organic compound into contact with the organic compound can be a method such as gas phase contact, coating, spraying, and dipping.

The organic compound used for hydrophobicity will be described. Preferred organic compounds having the effect of making the surface of the original plate hydrophobic are those which have a vapor pressure of at least 1 mmHg at a temperature of 400 ° C. and are stable at a temperature at which the vapor pressure becomes 1 mmHg. That is, if an organic compound having such a vapor pressure is present in a state in which it can come into contact with the original plate, the discrimination between hydrophilicity and hydrophobicity is improved. More preferably, it is an organic compound which has a vapor pressure of at least 1 mmHg at a temperature of 300 ° C. and is stable at a temperature at which the vapor pressure becomes 1 mmHg. More preferably, the boiling point is 30 to 400 ° C and 30 to 40
It is an organic compound that is stable in a temperature range of 0 ° C, and a preferred boiling point range is 50 to 350 ° C.

From another viewpoint, an organic compound having a vapor pressure of at least 10 mmHg at 20 ° C. is preferable.
In the case of solid compounds, ethanol, acetone,
Those which are dissolved in an organic solvent such as benzol or 2,2,4-trimethylpentane are preferable because they can be applied to the original plate in the form of a solution. Organic compounds having a boiling point in this temperature range include aliphatic and aromatic hydrocarbons, aliphatic and aromatic carboxylic acids, aliphatic and aromatic alcohols, aliphatic and aromatic esters, aliphatic and aromatic It is found in ethers, organic amines, organic silicon compounds, and various solvents and plasticizers which are not so effective but can be added to printing inks.

Preferred aliphatic hydrocarbons are those having 8 to 3 carbon atoms.
0, more preferably an aliphatic hydrocarbon having 8 to 20 carbon atoms, and a preferred aromatic hydrocarbon is 6 to 40 carbon atoms.
And more preferably an aromatic hydrocarbon having 6 to 20 carbon atoms. Preferred aliphatic alcohols have 2 to 30 carbon atoms.
Are more preferably aliphatic alcohols having 2 to 18 carbon atoms, and preferred aromatic alcohols are those having 6 to 30 carbon atoms.
And more preferably an aromatic alcohol having 6 to 18 carbon atoms. Preferred aliphatic carboxylic acids have 2 to 24 carbon atoms.
Aliphatic carboxylic acid, more preferably having 2 to 2 carbon atoms
Preferred are aliphatic monocarboxylic acids having 20 and aliphatic polycarboxylic acids having 4 to 12 carbon atoms, and preferred aromatic carboxylic acids are those having 6 to 30 carbon atoms, and more preferably having 6 to 30 carbon atoms.
18 aromatic carboxylic acids. Preferred aliphatic esters have 2 to 30 carbon atoms, more preferably 2 to 1 carbon atoms.
And preferred aromatic esters are those having 8 to 30 carbon atoms, more preferably 8 to 18 carbon atoms.
Is an aromatic carboxylate. Preferred aliphatic ethers are those having 8 to 36 carbon atoms, more preferably 8 carbon atoms.
To 18 aliphatic ethers, and preferred aromatic ethers are those having 7 to 30 carbon atoms, more preferably 7 to 1 carbon atoms.
8 aromatic ethers. In addition, carbon number 7-30
And more preferably an aliphatic or aromatic amide having 7 to 18 carbon atoms.

Specific examples include 2,2,4-trimethylpentane (isooctane), n-nonane, n-decane,
Aliphatic hydrocarbons such as n-hexadecane, octadecane, eicosane, methylheptane, 2,2-dimethylhexane and 2-methyloctane; aromatic hydrocarbons such as benzene, toluene, xylene, cumene, naphthalene, anthracene and styrene; dodecyl Monohydric alcohols such as alcohol, octyl alcohol, n-octadecyl alcohol, 2-octanol and lauryl alcohol; polyhydric alcohols such as propylene glycol, triethylene glycol, tetraethylene glycol, glycerin, hexylene glycol, dipropylene glycol; benzyl alcohol , 4-hydroxytoluene, phenethyl alcohol, 1-naphthol, 2-naphthol, catechol, aromatic alcohols such as phenol; acetic acid, propionic acid, butyric acid, Prong acid, acrylic acid, crotonic acid, capric acid, stearic acid, aliphatic monocarboxylic acids such as oleic acid; oxalic acid, succinic acid, adipic acid, maleic acid, polyvalent aliphatic carboxylic acids such as glutaric acid;
Aromatic carboxylic acids such as benzoic acid, 2-methylbenzoic acid and 4-methylbenzoic acid; ethyl acetate, isobutyl acetate,
Aliphatic esters such as n-butyl acetate, methyl propionate, ethyl propionate, methyl butyrate, methyl acrylate, dimethyl oxalate, dimethyl succinate and methyl crotonate; and methyl benzoate and methyl 2-methylbenzoate Aromatic carboxylic esters; organic amines such as imidazole, triethanolamine, diethanolamine, cyclohexylamine, hexamethylenetetramine, triethylenetetramine, aniline, octylamine, aniline, and phenethylamine; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and benzophenone , Methoxybenzene, ethoxybenzene,
Examples include ethers such as methoxytoluene, lauryl methyl ether, and stearyl methyl ether, and amides such as stearyl amide, benzoyl amide, and acetamide.

Further, oils and fats such as linseed oil, soybean oil, poppy oil, and safflower oil which are components of the printing ink, tributyl phosphate, tricresyl phosphate, dibutyl phthalate,
Plasticizers such as butyl laurate, dioctyl phthalate, and paraffin wax are also included.

In addition, organic solvents such as ethylene glycol monoethyl ether, cyclohexanone, methyl cellosolve, butyl cellosolve, cellosolve acetate, 1,4-dioxane, dimethylformamide and acrylonitrile having a boiling point within the above preferred range can also be used.

Preferred organosilicon compounds are organopolysiloxane compounds typified by dimethyl silicone oil, methylphenyl silicone oil, etc., and especially organopolysiloxanes having a degree of polymerization of 12 or less. These preferred organopolysiloxanes have one to two organic groups attached per siloxane bond unit,
The organic group includes an alkyl group and an alkoxy group having 1 to 18 carbon atoms, an alkenyl group and an alkynyl group having 2 to 18 carbon atoms, an aryl group having 6 to 18 carbon atoms, and a carbon atom having 7 to 18 carbon atoms.
An aralkyl group of 18 and an alicyclic group having 5 to 20 carbon atoms. Further, these organic substituents may be further substituted with a halogen atom, a carboxyl group, or a hydroxy group.
Further, the above-mentioned aryl group, aralkyl group and alicyclic group may be further substituted with a lower alkyl group such as a methyl group, an ethyl group or a propyl group within the above-mentioned carbon number range.

Specific examples of preferred organosilicon compounds that can be used in the present invention are the following compounds, but the present invention is not limited thereto. Preferred polyorganosiloxanes include a dialkylsiloxane group having an alkyl group having 1 to 5 carbon atoms, a dialkoxysiloxane group having an alkoxy group having 1 to 5 carbon atoms, and a 1 to 1 carbon atom.
5, at least one of an alkoxyphenylsiloxane group having an alkoxy group and a phenyl group and an ethoxymethoxysiloxane group or a methoxyethoxysiloxane group as a repeating unit, and having a degree of polymerization of 2 to 12, more preferably 2 to 10 It is an organosiloxane. Further, the terminal group is an alkyl group having 1 to 5 carbon atoms,
It is an amino group, a hydroxy group, a C1-5 hydroxyalkyl group or a C1-5 alkoxy group. More preferred terminal groups are methyl, ethyl, isopropyl, n-propyl, n-butyl, t-butyl, methoxy and ethoxy.

Among them, preferred siloxane compounds are
Dimethylpolysiloxane having a polymerization degree of 2 to 10, dimethylsiloxane having a polymerization degree of 2 to 10-methylphenylsiloxane copolymer, dimethylsiloxane having a polymerization degree of 2 to 8
A diphenylsiloxane copolymer, a dimethylsiloxane-monomethylsiloxane copolymer having a degree of polymerization of 2 to 8, and the terminal of these polysiloxane compounds is a trimethylsilane group. In addition, 1,3-bis (3-aminopropyl) tetramethyldisiloxane, 1,5-bis (3-aminopropyl) hexamethyltrisiloxane,
Dibutyl-1,1,3,3-tetramethyldisiloxane, 1,5-dibutyl-1,1,3,3,5,5-hexaethyltrisiloxane, 1,1,3,3,5,5- Hexaethyl-1,5-dichlorotrisiloxane, 3-
(3,3,3-trifluoropropyl) -1,1,3
3,5,5,5-heptamethyl-trisiloxane, decamethyltetrasiloxane and the like.

As particularly preferred siloxane compounds, there are commercially available so-called silicone oils, and dimethyl silicone oil (a commercially available product such as silicone KF96
(Manufactured by Shin-Etsu Chemical Co., Ltd.), methylphenyl silicone oil (commercially available, for example, silicone KF50 (manufactured by Shin-Etsu Chemical Co., Ltd.)), and methyl hydrogen silicone oil (commercially available, for example, silicone KF99 (Shin-Etsu Chemical Co., Ltd.) Co., Ltd.).

In addition, silane compounds such as n-decyltrimethoxysilane, n-decyltri-t-butoxysilane, n-octadecyltrimethoxysilane, n-octadecyltriethoxysilane and dimethoxydiethoxysilane can also be mentioned. .

Among the above organic compounds, particularly preferred compounds are silicone oil, fatty acids, glycerin esters and amides thereof, and aliphatic alcohols having 6 or more carbon atoms. Further, from another viewpoint, the organicity in the organic conceptual diagram is from 80 to 1200 (in the case of a polymer, per repeating unit), preferably from 100 to 600,
Organic compounds whose organic / inorganic ratio is in the range of 0.8 to infinity (that is, the inorganicity is 0), preferably 1.0 to 10. For the concept of organic concept, please refer to Yoshio Tanaka's "Concept of Organic Concept" (Sankyo Shuppansha, first edition published in 1983).
It is described in detail on page 31. It is unknown why the organic compounds in the above range on the organic conceptual diagram have an action of promoting hydrophobicity, but the compounds in this range have a moderate polarity and are relatively organic compounds. It is presumed that the appropriate polarity brings the adsorbing force to the original plate, and that its relatively large organic property makes the adsorption surface of the original plate hydrophobic.

A preferable method for bringing the organic compound into contact with the surface of the printing plate is that, in the case of a low-boiling organic compound, a jacket for vapor aeration is provided and a compound-filled container is placed in the jacket.
The vapor of the organic compound may be present in the mantle so that the printing plate in the mantle is exposed to the vapor. Further, paper, cloth, zeolite, diatomaceous earth, or the like impregnated with an organic compound may be inserted into the mantle.

When the organic compound is a liquid, a device for applying, spraying or dipping the liquid of the organic compound is provided in the above-mentioned mantle to bring the organic compound into direct contact with the surface of the original plate. In the case of a solid organic compound, an appropriate organic solvent such as methanol, acetone, benzol, 2,2,4-trimethylpentane or a liquid organic compound selected from the above-mentioned preferred organic compounds of the present invention is dissolved and dissolved therein. May be brought into contact as a solution by the method described above. Specific examples of the method of contacting these organic compounds with the printing original plate will be described in Examples.

Many of the metal oxides having photocatalytic properties, such as TiO ₂ , RTiO ₃ , AB _2-x C _x D _3-x E
_x O ₁₀ (the contents of A, B, C, D and E are as described above),
ZnO and SnO ₂ , and metal oxides having high-temperature hydrophilicity developing properties have a property of becoming hydrophobic when heated appropriately. The temperature for developing hydrophobicity is usually 50 to 2
50 ° C., which is lower than the hydrophilic expression temperature.
Instead of the hydrophobic method in which an organic compound is present, a hydrophobic method in which heating is performed at a temperature at which hydrophobicity is exhibited may be used. In that case, an organic compound may be present to promote hydrophobicity. This concludes the description of the method and operation of hydrophobization. The next step is to irradiate the hydrophobized surface imagewise with light, or to heat imagewise to obtain an imagewise distribution of the hydrophobic region and the hydrophilic region. Will be described.

(Imprinting hydrophilicity) When the printing original plate is made of a material having photocatalytic ability, the surface thereof is irradiated with light imagewise to form a hydrophilic region. The light source is a light source that emits light having a wavelength in a photosensitive region of a metal oxide having photocatalytic ability, that is, light having a wavelength corresponding to a light absorption region. For example, when the metal oxide having photocatalytic ability is titanium oxide,
Anatase type is 387 nm or less, rutile type is 413 nm
In the following, zinc oxide has a photosensitive region at 387 nm or less, and many other metal oxides also have a photosensitive region in the ultraviolet region of 250 to 390 nm, and in the case of zinc oxide, a specific absorption wavelength region (ultraviolet region). Besides, it is also possible to broaden the wavelength range of active light that can be applied by performing spectral sensitization by a known method,
Therefore, the light source used is a light source that emits light in these wavelength regions, and can be said to be a light source that mainly emits ultraviolet light. Means for forming an imagewise distribution of the hydrophilic region by the photocatalytic action of the active light may be any of a surface exposure method and a scanning method.

In the case of the surface exposure method, a method is used in which uniform light is irradiated onto the original plate through a mask image (for example, a lith film developed from a printed document) to make the surface of the irradiated area hydrophilic. When the support is transparent, exposure can be performed through the support and the mask image from the back side of the support. Light sources suitable for irradiating the active light by the surface exposure method include mercury lamps, tungsten halogen lamps, other metal halide lamps, xenon discharge lamps, and the like. The exposure time is determined in consideration of the exposure illuminance so as to obtain the above exposure intensity.

The preferable intensity of the irradiation light depends on the properties of the metal oxide having photocatalytic ability, and also depends on the wavelength of the active light, the spectral distribution and the light absorption of the metal oxide having photocatalytic ability. The surface exposure intensity before modulation with a mask image (for example, a developed lith film) is 0.0
5 to 100 joule / cm ² , preferably 0.05 to
10 joule / cm ² , more preferably 0.05 to 5
joule / cm ² . Also, often the photocatalytic reaction reciprocity is satisfied, for example, at 10 mW / cm ² 1
In many cases, the same effect can be obtained regardless of whether exposure is performed for 00 seconds or for 1 ^second at 1 W / cm ^{2. In} such a case, the range of selection of a light source that emits active light is limited. Become wider.

In the latter case, that is, in the case of scanning exposure, a method of scanning a master by electrically modulating a laser beam with an image instead of using an image mask is performed. As the laser light source, a known laser that oscillates a beam of active light can be used. For example, a helium cadmium laser having an oscillation wavelength of 325 nm, a water-cooled argon laser having an oscillation wavelength of 351.1 to 363.8 nm, and a zinc sulfide having an oscillation wavelength of 330 to 440 nm are used as excitation light.
Cadmium laser or the like can be used. Further, an ultraviolet laser, a gallium nitride-based InGaN-based quantum well semiconductor laser having an oscillation wavelength of 360 to 440 nm, for which near-ultraviolet laser oscillation has been confirmed, and a waveguide MgO-L having an oscillation wavelength of 360 to 430 nm
An iNb03 inversion domain wavelength conversion type laser can also be used. Irradiation can be performed with a laser having a laser output of 0.1 to 300 W. When a pulse laser is used, it is preferable to irradiate a laser having a peak output of 1000 W, preferably 2000 W. When the support is transparent, exposure can be performed through the support from the back side of the support.

On the other hand, when the printing plate is made of a metal oxide having a high-temperature hydrophilicity developing characteristic, the hydrophobicized surface is imagewise heated at a high-temperature hydrophilicity developing temperature to provide a hydrophilic region. I do. In this case, the temperature of the printing original plate surface at the time of forming an image-like distribution on the printing original plate surface needs to be higher than the hydrophobic expression temperature of the metal oxide having the high-temperature hydrophilicity developing characteristics. Although it depends on the physical properties of the substance, when the hydrophobic development temperature is 50 to 300 ° C., usually 1
It is in the range of 00 to 300 ° C, preferably 150 to 250 ° C.

The imagewise heating of the light heating system may be either a surface exposure system or a scanning system. In the former case, an infrared irradiation method or a method in which high-intensity short-time light from a xenon discharge lamp is irradiated onto a printing original plate through a mask image to generate heat by light-heat conversion. When a surface exposure light source such as an infrared lamp is used, the preferable exposure amount varies depending on the illuminance, but usually, the surface exposure intensity before being modulated with a print image is 0.1 to 10 J / cm ² . It is preferably in the range, more preferably in the range of 0.3 to 1 J / cm ² . When the support is transparent, exposure can be performed through the support and the mask image from the back side of the support. The exposure time is preferably selected so that the above-mentioned exposure intensity can be obtained by irradiation of 0.01 μsec to 10 msec, preferably 0.1 μsec to 1 msec. When the irradiation time is long, it is necessary to increase the exposure intensity due to the competition between the heat energy generation rate and the generated heat energy diffusion rate.

In the latter case, that is, in the case of the scanning method, a method of modulating a laser beam with an image using an infrared laser light source and scanning the original plate for printing is performed. Examples of the laser light source include a semiconductor laser, a gas laser, a helium cadmium laser, and a YAG laser having many components of near infrared rays and infrared rays. Irradiation can be performed with a laser having a laser output of 0.1 to 300 W. When a pulse laser is used, it is preferable to irradiate a laser having a peak output of 1000 W, preferably 2000 W. When the support is transparent, exposure can be performed through the support from the back side of the support.
When heating with light, for example, a light-to-heat conversion layer may be provided on a printing original plate, and the layer may absorb light energy to generate heat. Alternatively, it is also possible to heat the metal itself having high-temperature hydrophilicity characteristics by absorbing light and generating heat by itself. Examples of the light-to-heat conversion layer include a layer containing carbon black, a cyan dye, a pyrylium dye, and the like.

In the contact heating method, any known contact type thermal recording apparatus, for example, a thermal recording head of a thermal melting type and a sublimation type thermal dye transfer method is used. These include a method in which a single thermal recording element is driven two-dimensionally, a method in which an array of linearly arranged thermal recording elements is scanned in a perpendicular direction and drawing, or a high-speed drawing method using a two-dimensionally arranged recording element. A known thermal recording element can be used.

The second operation procedure of the printing method according to the present invention is described above.
The formation of the imagewise hydrophilic region, which is the stage, has been described. Since the image-wise distribution of the hydrophilic region and the hydrophobic region was formed by the operations of the first and second stages, printing can be performed as a printing plate also at this stage. In addition, a thin metal layer is provided by adding the following steps after electroless plating to improve the ink receiving ability (that is, prevent ink smear) and the printing durability, which are the objects of the invention. It is.

(Formation of Image-Like Metallic Thin Film) The third step is a step of forming a metal thin film on a hydrophilic region on a printing plate in which a hydrophobic region and a hydrophilic region are formed imagewise.

(Formation of image-like thin metal layer) In the third step, a thin metal layer is formed in a hydrophilic area having metal precipitation nuclei on a printing plate in which a hydrophobic area and a hydrophilic area are formed imagewise. This is the step of performing <Overview of Operation> An aqueous solution for electroless plating is brought into contact with the surface of a printing plate in which a distribution of hydrophobic and hydrophilic regions is formed imagewise. The contact method is not particularly limited as long as the metal is precipitated from the aqueous solution for electroless plating at least on the hydrophilic region having the metal precipitation nuclei, that is, if electroless plating is performed, immersion, coating, spraying, etc. May be. Also,
The conditions for the electroless plating are appropriately optimized, and the contact time of the aqueous solution for the electroless plating is usually 30 seconds to 10 minutes at room temperature, preferably 1 to 5 minutes. The temperature of the aqueous solution is usually 10 to 90 ° C., preferably 20 to 90 ° C.
It is in the range of 40 ° C. The thickness of the thin metal layer formed by electroless plating is usually 0.01 to 5 μm, preferably about 1 μm. An aqueous solution for electroless plating can be brought into contact with a hydrophilic region having metal deposition nuclei on the surface of a printing plate to form a thin layer by electroless plating of a metal from a water-soluble metal compound. Becomes On the other hand, even if the image-like hydrophobic region is in contact with the aqueous solution, the region is intact because the metal ion does not move or precipitate due to the hydrophobicity. Therefore, in the next fourth step, when the hydrophobic region is subjected to a hydrophilic treatment by removing an organic compound or the like, this region is more hydrophilic than the plated region, and therefore becomes ink repellent.

The technical idea of the present invention can be simply described as follows. It is unnecessary to use a complicated apparatus for naturally depositing a metal on a metal deposition nucleus from an aqueous solution for electroless plating in a hydrophilic region having the metal deposition nucleus. And a thin metal layer faithful to the imagewise distribution formed on the surface of the printing original plate. In the specification of the present application, electroless plating means spontaneous precipitation of metals from various solid / liquid systems and liquid / liquid systems represented by silver mirror reactions. That is, electroless plating is performed by selecting a natural metal ion oxidation-reduction process in which free energy is released under conditions that can be easily realized from room temperature to about 90 ° C. As a result, it has been found that precipitation of the metal proceeds without difficulty, which leads to higher precision of the metal thin layer pattern.

The details of the present invention embodying such a technical idea will be described below. The water-soluble metal compound to be used in the present invention may be any compound containing a metal that can be used as a metal thin layer pattern. That is, as will be described later, the conditions for precipitating the desired metal can be adjusted by selecting the reducing compound, that is, the reducing agent and the pH, so that any practical metal compound is an object of the present invention. First, basic conditions for forming a thin metal layer pattern by the method of the present invention will be described.

The conditions under which the thin metal layer pattern is formed by the natural precipitation are an aqueous solution containing a water-soluble metal compound and a reducing agent, and the oxidation potential of the reducing agent is reduced by the reduction potential of the water-soluble metal compound. Is lower (lower potential) than that. The oxidation potential or reduction potential in this case can be determined from the oxidation wave or reduction wave when the water-soluble metal compound and the reducing agent are repeatedly scanned in the oxidation and reduction directions by cyclic voltammetry. The oxidation potential is a potential corresponding to the maximum current of the oxidation wave, and the reduction potential is a potential corresponding to the maximum current of the reduction wave. Regarding cyclic voltammetry and methods of measuring oxidation potential and reduction potential using the same, appropriate books in this field, for example, Tetsuya Osaka,
It is described in Noboru Koyama and Takeo Osaka, "Electrochemical Method / Basic Manual (Third Edition)" (Kodansha, 1990), edited by The Electrochemical Society of Japan, "New Edition of Electrochemical Measurement" (1988).

If the oxidation potential of the reducing agent is lower than the reduction potential of the water-soluble metal compound, precipitation of the metal pattern should occur. It is preferable to select a reducing agent so that the difference in reduction potential is 20 mV or more, or to adjust conditions such as pH on the reducing agent. If the difference between the oxidation and reduction potentials is large, metal precipitation occurs in the non-image area (that is, the non-pattern area), and the aqueous solution itself rapidly deteriorates. Therefore, the practical range is 0 to 1.5 V, preferably 20 mV to 1.0 V. More preferably, 20 to 5
00 mV.

Next, the water-soluble metal compound applicable to the present invention will be described. Metals that have practical value and are convenient as an application object of the present invention are stable metals having low electric resistance and hard to corrode, and therefore, a metal element constituting a water-soluble metal compound preferably applicable to the present invention is The ionization tendency is equal to or less than the chromium element, that is, a noble one. These metal elements include chromium, cobalt, nickel, tin, titanium, lead, iron (III), copper, molybdenum, tungsten, rhodium, iridium, palladium, mercury, silver, platinum, and gold.

Among them, particularly preferred metal elements constituting the water-soluble metal compound are silver, copper, nickel, lead, palladium, gold, platinum, tungsten, titanium, cobalt, and chromium. Gold, silver, and copper satisfy all the practical characteristics required for forming a thin metal layer, such as toughness and flexibility. On the other hand, the form of the salt constituting the water-soluble metal compound is
Any known salt form can be selected as long as it is water-soluble, but preferred salt forms are sulfates, carbonates, nitrates, halides including chlorides, thiocyanates, and the like. Further, a complex salt formed with ammonium hydroxide, thiosulfate ion, cyanide ion or the like can also be preferably used.

The preferred concentration of the water-soluble metal compound in the aqueous solution for electroless plating varies depending on the intended thin metal layer pattern, but is generally 0.01 to 10 mol / l, preferably 0.05 to 3 mol / l. Range.

Next, the reducing agent combined with the water-soluble metal compound will be described. As described above, the condition of the reducing agent is that the oxidation potential of the reducing agent is lower than the reduction potential of the water-soluble metal compound combined in the aqueous electroless plating aqueous solution system, but its practical meaning is That is, the maximum potential of the oxidation wave of the reducing compound is more negative (base side) than the maximum potential of the reduction wave of the water-soluble metal compound.
More preferably, the reduction potential of the water-soluble metal compound is more noble than the oxidation potential of the reducing compound by at least 20 mV.

Considering the deposition rate and the like, a more practical guide is that the maximum potential of the oxidation wave is +100 to -700 mV.
Reducing compounds such as (SCE) are preferred. Many oxidation and reduction reactions require hydrogen ion (or hydroxyl ion)
, The maximum potential of the oxidation wave in the cyclic voltammetry of the reducing compound varies greatly depending on the pH. Therefore, by adjusting the pH, it is possible to select a condition capable of deposition and an appropriate deposition rate.If the water-soluble metal compound is the gold, silver or copper compound described above, the appropriate maximum oxidation potential of the reducing agent is determined by adjusting the pH of the aqueous solution. It is +100 to -700 mV (SCE) in the system. Preferred reducing agents that fall within this potential range in an aqueous electroless plating system will be described in more detail below.

Specific examples of the reducing agent will be described. (1) Saccharides and Carbohydrates Saccharides and carbohydrates such as starch in a polymerized form thereof are suitable reducing agents in the present invention. Although its reducibility is originally considered to be zero, its reducibility sufficiently reduces noble metal salts and heavy metal salts in an alkaline environment. In addition, since it can be present at a high concentration and the reduction reaction proceeds uniformly, it is possible to accurately form even a fine pattern. Preferred specific compounds include the following. More preferred are dextrins.

Specific examples of the monosaccharide of the present invention are shown below. The monosaccharides include the following. That is, glyceraldehyde, dihydroxyacetone (including dimer), erythrose, threose, report,
Arabinose, xylose, lyxose, xylulose, ribulose, deoxy-D-ribose, allose,
Altrose, glucose, mannose, growth, idose, galactose, talose, quinoboth, digitalose, digitoxose, simarose, sorbose, tagatose, fucose, 2-deoxy-D-glucose,
Bucose, fructose, rhamnose, D-glucosamine, D-galactosamine, D-mannosamine, D-glycero-D-galactoheptose, D-glycero-D /
L-mannoheptose, D-glycero-D-gloheptose, D-glycero-D-idoheptose, D-glycero-L-glucoheptose, D-glycero-L-taloheptose, altroheptulose, mannoheptulose,
Altro-3-heptulose, glucuronic acid, N-acetyl-D-glucosamine, glycerin, trait, erythlet, arabit, adnit, xylit, sorbit, mannitol, idit, talit, zulcit, allozurcit.

Among these exemplified compounds, xylose, glucose, mannose, galactose, sorbose, D-glycero-D / L mannoheptose, glycerin, sorbit, mannitol and the like are preferably used.

The following are specific examples of the polysaccharide of the present invention. Maltose, cellobiose, trehalose, gentiobiose, isomaltose, lactose, raffinose, gentianose, stachyose, xylan, araban, glycogen, dextran, inulin, leban, galactan, agarose, amylose, sucrose, agaropiose, α-dextrin, β-dextrin -Dextrin, δ-dextrin, ε-dextrin, soluble starch, thin nori starch and the like. Examples of the polysaccharide derivatives include methylcellulose, dimethylcellulose, trimethylcellulose, ethylcellulose, diethylcellulose, triethylcellulose, carboxymethylcellulose, carboxyethylcellulose, aminoethylcellulose, hydroxymethylcellulose, hydroxyethylmethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, and hydroxypropylcellulose. Propylmethylcellulose acetate succinate, carboxymethylhydroxyethylcellulose and the like can be used.

Among these exemplified compounds, those preferably used include maltose, lactose, dextran, inulin, amylose, sucrose, α-dextrin, β-dextrin, γ-dextrin, soluble starch, methylcellulose, ethylcellulose, carboxymethylcellulose, carboxymethylcellulose, Ethyl cellulose, hydroxymethylcellulose, hydroxyethylmethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, hydroxypropylmethylcellulose acetate succinate, carboxymethylhydroxyethylcellulose and the like can be used.

In the present invention, the added amount of these saccharides is
Usually, it is 0.1 to 30% by weight, preferably 0.5 to 15% by weight, and desirably has a stoichiometrically larger amount than the water-soluble metal compound. 1. For water-soluble metal compounds.
It is convenient to use 0 to 10 equivalents, preferably 1.03 to 3 equivalents, but the optimum range varies depending on the presence of a water-soluble metal compound, a complex-forming compound and the like.

Saccharides exist widely and naturally, and commercially available products are easily available. Also, various derivatives can be easily synthesized by performing reduction, oxidation, dehydration, or the like. When a saccharide is used as a reducing agent, the pH of the aqueous solution is preferably 8 or more, more preferably 10 or more.
The number is preferably 12 or more. The upper limit may be pH 14 or the concentration of alkali hydroxide may be 10%.

(2) Aldehydes As can be considered from examples of Fehling's solution, aldehydes can be used as the reducing agent used in the present invention. The aldehyde compounds that can be used as the reducing agent of the present invention include, specifically, aliphatic saturated aldehydes such as formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, aliphatic dialdehydes such as glyoxal and succindialdehyde, and acrolein. ,
In addition to unsaturated aldehydes such as crotonaldehyde and propioaldehyde, aromatic aldehydes such as benzaldehyde, saltyl aldehyde and naphthaldehyde, and heterocyclic aldehydes such as furfural, sucrose having an aldehyde group and a ketone group, and monosaccharides such as glucose, Preferred are oligosaccharides such as fructose and oligosaccharides, and monosaccharide-substituted deoxy sugars, methyl sugars, thio sugars and amino sugars.

The preferred concentration of the aldehyde compound is usually 0.02 to 5.0 mol, preferably 0.1 to 2.0 mol per liter of the aqueous solution. Also, when aldehydes are used as the reducing agent, alkaline conditions are preferable, and usually pH 7-14, preferably 9-12.

(3) Developing agents Hydroquinones such as hydroquinone and monochlorohydroquinone, catechols such as catechol, catechol and pyrocatechol, p-aminophenol, N- and the like, which are also known as photographic developing agents P-Aminophenols such as methyl-p-aminophenol, p-phenylenediamines such as p-phenylenediamine, 2-methyl-p-phenylenediamine, diethyl-p-phenylenediamine, o-phenylenediamine, 1-phenyl 3-pyrazolidones such as -3-pyrazolidone, 3-aminopyrazoles, 4-amino-pyrazolones, 5-aminouracils, 4,5-dihydroxy-6-aminopyridines, ascorbic acid, erythorbic acid, reductic acid Such as reductones, o -Or p-sulfonamidonaphthols, o- or p-sulfonamidophenols, 2,4-disulfonamidophenols, resorcinol, resorcinols such as diaminoresorcinol, 2,4-disulfonamidonaphthols,
o- or p-acylaminophenols, 2-sulfonamidoindanones, 4-sulfonamido-5-pyrazolones, 3-sulfonamidoindoles, sulfonamidopyrazolobenzimidazoles, sulfonamidopyrazolobenztriazoles And hydrazines such as sulfonamide ketones, arylhydrazine, phenylhydrazine and hydrazobenzene. In particular, reductones are preferable because their oxidized form does not adversely affect the oxidized product. Particularly preferred reductones are ascorbic acid, erythorbic acid, glucoreductone, reductonic acid. The concentration of the developing agent is usually
0.005 to 1.0 mol, preferably 0.05 to 0.5
Is a mole. Also, when developing agents are used as a reducing agent, alkaline conditions are preferable, and usually pH 7 to
14, preferably 9 to 12.

Next, the complex forming compound preferably used in the present invention will be described. In the system of the aqueous solution for electroless plating, since the reductive precipitation of the water-soluble metal compound often competes with the formation reaction of the metal hydroxide, the aqueous solution is often unstable. Therefore, in the present invention, it is appropriate to increase the stability of the water-soluble metal compound by causing the complex forming compound for the metal ion to be present in the aqueous solution for electroless plating of the water-soluble metal compound. Such complexing compounds have a total stability constant for metal ions of at least 10
^The number is preferably ³ or more, and a system in which the complex-forming compound is present in at least equimolar amount to the water-soluble metal compound is selected. Preferred complex-forming compounds satisfying such conditions for water-soluble metal compounds, especially gold, silver and copper compounds, are selected from nitrogen-containing organic compounds, sulfur-containing organic compounds and oxygen-containing organic compounds. Particularly suitable complexing compounds are selected from the group consisting of halides, thiocyanic acids, cyanides, alkanolamines, aliphatic amines, cyclic amines, amino acids, ammonia, thiourea and thiosulphate. Specific examples are shown below, but the complex forming compound applied to the present invention is not limited thereto.

Chlorine ion, bromine ion, iodine ion,
Cyanide ion, thiocyanate ion, sulfite ion, thiosulfate ion, thiourea, aliphatic primary amine (linear or branched dodecylamine, hexylamine, nonylamine, pentadecylamine, etc.), cyclic amine (pyridine, imidazole, -Methylimidazole, triazole, thiadiazole, picoline, piperazine, pyrrole, piperidine, pyrazine, pyrimidine, pyridazine, isothiazole, quinoline, isoquinoline, etc.),
Alkanolamines (diethanolamine, monoethanolamine, isopropanolamine, tri-isopropanolamine, etc.), polyamines (triethylenetetramine, pentaethylenehexamine, diethylenetriamine, ethylenediamine, etc.), amino acids (alanine,
Arginine, histidine, cysteine, methionine, glutamine, etc.), thiol (thioglycol, etc.), thiosemicarbazide, thiouracil. Regarding the complexing compound for silver ions, see TH James, "The theory of photographic processes 4th ed.
llan) on pages 8-11.

The preferable addition amount of the complex-forming compound is usually
The amount of the water-soluble metal compound is 1 to 200 times, preferably 2 to 200 times.
100-fold, more preferably 3 to 20-fold in the case of complexing compounds having a large complexing constant, such as thiosulfates,
In the case of an alkali halide, for example, potassium bromide, which is a complex forming compound having a relatively small complexing constant, 10 to 100
It is twice.

Among the above-mentioned complex forming compounds of metal ions, particularly preferred are alkali metal salts and alkaline earth metal salts of each ion such as chloride ion, bromine ion, cyanide ion, thiocyanate ion and thiosulfate ion. ,
The bases themselves such as ammonium salt, thiourea, ammonia, imidazole, 2-methylimidazole, and ethylenediamine, or their chlorides, sulfates, hydrochlorides, etc.

The aqueous solution for electroless plating is added with an alkali agent for adjusting the pH to an appropriate value, an acid and, if necessary, a pH buffering agent for stably maintaining the pH. Alkali agents or buffers include alkali metal hydroxides, alkaline earth hydroxides, carbonates, phosphates, borates,
Tetraborate, hydroxybenzoate, glycyl salt, N,
N-dimethylglycine salt, leucine salt, norleucine salt, guanine salt, 3,4-dihydroxyphenylalanine salt, alanine salt, aminobutyrate, 2-amino-2-methyl-1,3-propanediol salt, valine salt, proline Salts, trishydroxyaminomethane salts, lysine salts and the like can be used. In particular, carbonate, phosphate, tetraborate, and hydroxybenzoate have excellent buffering capacity in a high pH region of pH 9.0 or more.

Specific examples of these alkali agents and buffers include potassium hydroxide, sodium hydroxide, calcium hydroxide, magnesium hydroxide, tetramethylammonium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate and bicarbonate. Potassium, trisodium phosphate, tripotassium phosphate, disodium phosphate, dipotassium phosphate, sodium borate, potassium borate, sodium tetraborate (borax), potassium tetraborate, sodium o-hydroxybenzoate (Sodium salicylate),
Examples thereof include potassium o-hydroxybenzoate, sodium 5-sulfo-2-hydroxybenzoate (sodium 5-sulfosalicylate), and potassium 5-sulfo-2-hydroxybenzoate (potassium 5-sulfosalicylate). However, the invention is not limited to these compounds. When the alkali agent and the buffering agent are used in combination, they are contained in a total amount of 0.02 to 5.0 mol / l, particularly 0.1 mol / l to 2.0 mol / l.

Next, prior to the step of bringing an aqueous solution for electroless plating containing a water-soluble metal compound and a reducing compound into contact with an original plate for printing to deposit a metal thin film, as described above, The metal precipitation nuclei provided will be described. Metal precipitation nuclei usually take discrete forms.

The metal deposition nuclei are fine particles having a surface on which metal atoms are preferentially deposited when a metal is reduced from an aqueous solution for electroless plating containing a water-soluble metal compound. The metal precipitated on the metal nuclei from the aqueous plating solution comes into contact with adjacent particles as it grows, and the metal is grown from discrete metal nuclei into a continuous thin metal layer. By providing the metal deposition nuclei in advance, not only the metal deposition rate is high, but also a metal thin layer pattern with excellent shape accuracy without protrusion or depression in the lateral direction and the thickness direction can be obtained. In addition, the deposited metal is taken into the crystal lattice to obtain a high density close to the density of a single metal, which is extremely effective in improving the printing durability.

Such metal precipitation nuclei are fine particles in which metal deposition occurs preferentially. Preferred nuclei are metal elements having a relatively lower ionization tendency, particularly chromium having a lower ionization tendency than chromium. Metal fine particles selected from metal elements, metal elements belonging to heavy metals, and metal elements belonging to transition elements. Particularly preferred metal precipitation nuclei are
Metal fine particles obtained from a sol of at least one metal element selected from silver, copper, nickel, zinc, palladium, gold, platinum, molybdenum, tungsten, titanium, cobalt and chromium.

The metal fine particles acting as metal deposition nuclei and the metal deposited on the metal from the aqueous solution for electroless plating need not necessarily be the same kind of metal element. For example, a deposition nucleus of palladium may be used to deposit a silver thin film pattern.

These metal fine particles may be fine particles containing the metal as a single component, or may be fine particles of an alloy of a plurality of the above-mentioned elements. To prepare the metal fine particles, any known method can be used,
Reduction from an aqueous solution is a preferred method in that fine particles can be appropriately dispersed and obtained without aggregation. In order to prepare metal fine particles by this method, an aqueous solution of a water-soluble metal compound which is made alkaline with an alkali hydroxide or tribasic phosphate at a pH of 7 or more, preferably 8 or more, more preferably 10 to 14.0, is prepared. Then, a reducing agent is added to prepare metal fine particles. Any water-soluble metal compound may be used as long as it is water-soluble, but nitrate, chloride, sulfate and the like are preferable. The concentration depends on the pH of the sol, the coexisting reducing agent and the preparation device, but is used at a concentration of 0.1 to 10 mol, preferably 0.2 to 3 mol.

As the reducing agent, any of the reducing agents described above as a water-soluble reducing agent may be used, but saccharides such as monosaccharides and oligosaccharides, aldehydes and the like are preferable in view of a wide range of control. The concentration depends on the pH of the sol, the water-soluble metal compound and the preparation device, but it is used at a concentration of 0.1 to 10 mol, preferably 0.2 to 3 mol. It is preferable that an appropriate protective colloid is added to the aqueous solution. The reduction reaction is preferably performed under a high degree of agitation, but increasing the viscosity by adding a protective colloid is an undesirable direction in this respect. Therefore, when performing the reduction reaction, it is effective to control the addition amount of the protective colloid and to allow an appropriate dispersant or surfactant to be present. As protective colloids used for such purposes, hydroxyethyl cellulose, hydroxypropyl cellulose,
Examples thereof include water-soluble polymers such as hydroxy or carboxyalkyl cellulose represented by carboxymethyl cellulose, gelatin, polyvinyl alcohol which may be partially saponified, and polyvinyl acetal. Particularly preferred are gelatin and hydroxyalkyl or carboxyalkyl cellulose. The preferred concentration is such that the viscosity of the solution is 0.01-100 cp, more preferably 0.02-1 cp.
The amount added is in the range of 0 cp, often in the concentration range of 0.1 to 10%, preferably 0.4 to 3%.

As the dispersing aid, specific examples of surfactants exemplified later as nonionic, anionic and cationic surfactants which can be added to the aqueous solution for electroless plating used in the present invention. Can be selected from those having a large dispersing effect. As an activator having such a large dispersing effect, a sulfonate and a polyalkylene glycol group of a condensation polymer having a polymerization degree of 2 to 10 with a phenol such as naphthol and phenol and a lower aliphatic aldehyde such as formaldehyde and glutaraldehyde are used. Anionic surfactants are preferred. In particular, polyoxyethylene glycol and polyoxyethylene / polyoxypropylene copolymers and their sulfonic, phosphonic or carboxylic acid substituted anionic activators are preferred. A particularly preferred example of a method for preparing metal fine particle nuclei is that a water-soluble metal compound serving as a metal precipitation nucleus is silver nitrate, the concentration of which is 0.1 to 1 mol, and the pH is adjusted by adding sodium hydroxide.
0 to 13.8, the reducing agent is dextrin obtained from starch, and its concentration is 5 to 80 g / l, and gelatin is 3 to 70 g / h as a hydrophilic colloid substance for improving dispersibility.
This is silver fine particles obtained by adding 1 liter and reacting at a temperature of 30 to 50 ° C. Among these silver fine particles, a particularly advantageous one is a silver fine particle dispersion having an average particle size of 10 to 80 nm used as a yellow filter layer of a color photographic light-sensitive material.

Further, in the present invention, the activity is increased by making the particles finer, and the metal deposition rate is often increased. However, the finer the particles, the more difficult the production becomes. It is also possible to produce a colloid nucleus in which the element is carried to form substantially extremely fine particles, which is used as a highly active metal precipitation nucleus. Such a colloidal dispersion that can be a metal element alone is a sol-like dispersion of fine powder of silicic anhydride (silica), also called colloidal silica. A preferred element supported on the sol-like silica fine particles and functioning as a metal precipitation nucleus is at least a metal element belonging to silver, copper, nickel, zinc, palladium, gold, platinum, molybdenum, tungsten, titanium, cobalt and chromium. One kind.

As the silica fine particle dispersion, a sol in which fine powder of crystalline or amorphous silica is dispersed in water can be used. In this case, an appropriate surfactant is added to the sol system in order to improve dispersibility, or a hydroxy or carboxyalkyl cellulose represented by hydroxyethylcellulose or carboxymethylcellulose, gelatin, polyvinyl alcohol, polyvinyl acetal or the like is used. A conductive polymer may be added as a dispersing aid. The preferred concentration is the same as the concentration range described above as the condition used for preparing the metal precipitation nuclei composed of metal fine particles. Another form of the silica fine particle dispersion is to dissolve an alkali silicate such as sodium silicate in an aqueous alkali solution to form a water glass solution, dissolve the water-soluble metal compound therein, and then stir the aqueous mixture. Under the condition, a silica sol supporting a metal element may be prepared by a known method such as rapid water dilution, pH reduction by acid addition, and rapid addition of an organic solvent.

Among the above-mentioned metal elements which exhibit an effect in the form of being supported by silica particles, particularly preferred elements are silver, copper, nickel and palladium. In order to be effectively supported on the silica particle surface, the p of the sol dispersion system is required.
H is 7 or more, preferably 8 or more, more preferably 10 or more.
It is preferably an alkaline of 14.0, and it is considered that the hydrated form of the silica surface is preferable for deposition of fine metal elements. To make it alkaline, any water-soluble alkaline compound can be used,
In particular, alkali hydroxide and tribasic phosphate are preferred. The water-soluble metal compound for supplying the metal element for precipitating the metal precipitation nucleus may be any water-soluble metal compound, but is preferably a nitrate, a chloride or a sulfate. The concentration depends on the pH of the sol, the coexisting reducing agent and the compounding device, but is usually 0.1 to 10 mol, preferably 0.2 to 3 mol. The silica fine particles may be commercially available, and the concentration is usually 0.1 to 100 g / l, preferably 1.0 to 10 g / l. The preferred concentration of the alkali silicate when preparing the metal-supported core from the alkali silicate is also in the same range.

In depositing the metal on the silica fine particles, it is preferable to coexist a small amount of a reducing agent. As the reducing agent, any of the reducing agents described above as a water-soluble reducing agent may be used, but saccharides such as monosaccharides and oligosaccharides, aldehydes and the like are preferable in view of a wide range of control. Its concentration is
Depending on the pH of the sol, the water-soluble metal compound and the compounding device,
It is used at a concentration of 0.1 to 10 mol, preferably 0.2 to 3 mol. The reaction temperature may be selected from a wide range of 0 to 90 ° C, but the preferred range is 10 to 70 ° C, most preferably 40 to 60 ° C. A particularly preferred example of the method for preparing metal fine particles with silica fine particles interposed therebetween is to disperse colloidal silica or sodium silicate in sodium hydroxide in water, and adjust the pH to 12.8 to 14.3 with sodium hydroxide or potassium hydroxide. 0.3 as 0
5%, preferably 0.4 to 2% water glass, into which silver nitrate as a water-soluble metal compound having a concentration of 0.1 to 1%.
Mol, dextrin or glucose as a reducing agent at a concentration of 5 to 80 g / l, and polyvinyl alcohol, polyvinylpyrrolidone or gelatin as a hydrophilic colloid substance for improving dispersibility at 2 to 50 g / l. These are silver-supported silica fine particles obtained by the reaction. Among these silver-supported silica fine particles, a particularly preferable one is a silver-supported silica sol having a particle size of 10 to 150 nm.

Another preferable method for preparing silver-supported silica fine particles is to disperse colloidal silica in water as a silica sol dispersion without forming water glass in the above method, and then add silver nitrate as described above. This is a method of making alkaline, adding a reducing agent to precipitate reduced silver on the surface of the silica particles, and preferable pH, reducing agent concentration, silver salt concentration, protective colloid and its concentration are as described above.

The metal nuclei which are advantageous for the present invention are not limited to metal elements. A sulfide of a metal selected from silver, copper, nickel, zinc, palladium, gold, cobalt and chromium is also preferably used. Among them, nickel sulfide, tin sulfide, cobalt sulfide, silver sulfide, palladium chloride and the like are preferable. For example, dissolve nickel sulfate in water,
It is obtained by adding an alkali sulfide such as sodium sulfide. The formation of sulfide particulates is often less than neutral p
H, especially hydrochloric acid, sulfuric acid, phosphoric acid, etc. to adjust the pH to 0.5-5.
It is preferably carried out at a pH of 0, preferably 1.0 to 3.0.

For example, when providing a palladium nucleus,
The printing plate is treated with a tin chloride solution obtained by dissolving 0.2 to 0.5 mol of tin chloride per liter of a 0.01 to 0.1 mol aqueous hydrochloric acid solution at room temperature for 1 to 10 minutes. 01 ~
0.1 to 0.5 per liter of 0.1 molar hydrochloric acid aqueous solution
For example, a palladium chloride solution obtained by dissolving g of palladium chloride is treated at room temperature for 1 to 3 minutes. In such a case, a palladium complex salt such as potassium palladium chloride may be used instead of palladium chloride. In the case where metal fine particles such as platinum, iridium, and rhodium are provided as metal deposition nuclei in addition to palladium, the treatment can be performed with an acidic aqueous solution of each metal compound in the same manner as described above. In the above-mentioned treatment, the protective colloid, the surfactant and the like described in the section of the method for preparing the metal fine particle nucleus can be used for the same purpose.

As the metal precipitation nucleus, those conventionally known as development nuclei in physical development of a silver halide photosensitive material are also preferable. In particular, known physical development nuclei used for photographic image formation by the silver salt diffusion transfer method can be used. Many physical development nuclei are sedimentation nuclei of one of the following metals, especially gold or silver, which tend to ionize (that is, nuclei that form a pan where gold and silver precipitate image-wise from solution) and contain silver salts. The known physical development nuclei of the diffusion transfer method are preferred. Suitable physical development nuclei are, in addition to metal fine particles selected from silver, copper, nickel, zinc, palladium, gold, cobalt and chromium, colloids such as gold and silver, and water-soluble salts such as palladium, nickel and zinc. Metal sulfide obtained by mixing sulfide and sulfide, and selenium compounds of lead, zinc, antimony, and nickel can be used. As the protective colloid, various protective colloids such as polyvinyl alcohol and partially saponified polyvinyl alcohol and polyvinylpyrrolidone can be used. However, if the amount is large, the ink receptivity deteriorates. Therefore, it is preferable to use a small amount as long as the function is satisfied.

The principle of the silver salt diffusion transfer method is described in “Photographic Silver Halide Diffusion Transfer” by Andre Rott et al.
Process "The Focal Press (1972) and many other books on photographic chemistry.
Grafkides's Science and Practices of Photographic
Matrials (7th ed.) Pages 101-130. Other examples include U.S. Pat.
No. 11,656, JP-A-63-260491, JP-A-7-56351, JP-A-8-314131, and European Patent 0483415A1.

In the present invention, the process of providing the metal deposition nuclei on the printing original plate can be performed after the etching process. This etching treatment may be performed beforehand on the surface of the printing original plate before making the printing original plate hydrophobic, or may be performed on the formed hydrophilic region.

The etching treatment can be performed by treating a mixed solution of phosphoric acid and sulfuric acid or a chromic sulfuric acid solution at 60 to 70 ° C. for 10 to 30 minutes. A preferred phosphoric acid / sulfuric acid mixture is a strong acid solution of phosphoric acid 4-8N and sulfuric acid 6-18N. A preferred chromium / sulfuric acid mixture is prepared by dissolving 200 to 500 g of chromium oxide in 2 to 6N sulfuric acid. The surface of the printing original plate is roughened by etching.

As described above, the method of depositing a metal from an aqueous solution for electroless plating on a metal deposition nucleus and forming a metal thin film pattern of a continuous phase based on the metal has a simple pattern manufacturing process. Therefore, the metal thin layer pattern obtained can be easily and inexpensively prepared, and the obtained metal thin layer pattern has high uniformity even in the thickness direction without protruding into the non-image portion which is a hydrophobic area and no depression, and has excellent printing durability. A thin layer pattern is obtained. The size of the metal fine particle nucleus or the metal sulfide fine particle nucleus is usually 3 to 1000 nm, preferably 5 to 500 nm, more preferably 10 to 100 n.
m.

The description of the metal deposition nucleus has been completed above, and other components of the aqueous solution for electroless plating for depositing a metal on the metal deposition nucleus will be further described. A surfactant can be added to the aqueous solution for electroless plating in order to promote uniform and smooth metal deposition and improve the accuracy of the formed thin metal layer pattern. The surfactants may be any of nonionic, anionic (both amphoteric) and cationic surfactants as long as they reduce the contact angle between the aqueous solution and the substrate material. And anionic surfactants are preferred. Preferred nonionic surfactants include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, polyoxyethylene alkyl ethers such as polyoxyethylene oleyl ether, polyoxyethylene octyl phenyl ether, and polyoxyethylene octyl phenyl ether. Polyoxyethylene alkyl aryl ethers such as ethylene nonyl phenyl ether, polyoxyethylene / polyoxypropylene block copolymers, and further, an aliphatic group having 5 to 24 carbon atoms in the hydroxyl group at the terminal of the polyoxyethylene / polyoxypropylene block copolymer Is a complex polyoxyalkylene alkyl ether having an ether bond, and is also a complex polyoxyalkylene alkyl having an alkyl-substituted aryl group is an ether bond. Sorbitan fatty acid esters such as reel ethers, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, sorbitan tristearate, polyoxyethylene sorbitan monolaurate, polyoxyethylene And polyoxyethylene sorbitan fatty acid esters such as sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, and polyoxyethylene sorbitan tristearate.

Examples of the anionic surfactants include alkyl sulfonic acids, aryl sulfonic acids, aliphatic carboxylic acids, aromatic carboxylic acids, alkyl naphthalene sulfonic acids, naphthalene sulfonic acid or a condensation type of alkyl naphthalene sulfonic acid and formaldehyde. Carbon number 9
To 26 aliphatic carboxylic acids, aliphatic sulfonic acids having 9 to 26 carbon atoms, alkylbenzene sulfonic acids, lauroyl polyoxyethylene sulfate, stearoyl polyoxyethylene sulfate, cetyloxy polyoxyethylene sulfonic acid, oleiroyl polyoxyethylene phosphonic acid And polyoxyethylene-containing sulfuric acid and polyoxyethylene-containing phosphoric acids. The addition amount of these surfactants is 1 liter per aqueous solution of water-soluble electroless plating.
Usually, it is 0.1 to 10 g, preferably 0.5 to 5 g. These surfactants may be added alone or in some combination.

The aqueous solution for electroless plating of the present invention contains a water-soluble metal compound, a reducing agent, and more preferably a complex-forming compound for a metal, and further contains a suspended metal precipitate spontaneously reduced in the solution. A water-soluble polymer can be added to uniformly disperse and keep from coarsening. The water-soluble polymer compound has a certain viscosity increase when dissolved in an aqueous solution, has a protective colloid effect, and furthermore, oxidizes and dissolves the aqueous solution.
As long as it is a polymer compound having no oxidizing or reducing substituent that affects the reducing property, it can be generally used. As for the viscosity, the amount added is preferably such that the viscosity becomes 0.05 to 50 cp (cp is centipoise), and preferably 0.1 to 20 cp. A method for forming a thin metal layer pattern by contacting a printing original plate with an aqueous solution for electroless plating containing a water-soluble metal compound and a reducing agent will be described later, but is performed by immersing the printing original plate in an aqueous solution for electroless plating. In the case of the method, an aqueous solution having a relatively low viscosity may be used, for example, an aqueous solution having a viscosity of 5 cp or less. In the case of applying an aqueous solution for electroless plating on a substrate with a resist pattern, a viscosity of 1 cp or more may be provided. Good. In order to determine the viscosity, that is, the viscosity, an appropriate measuring range can be selected from a falling ball viscometer, a rotational viscometer, an Ostwald viscometer, and any general-purpose viscometer having the same principle as any of these. The above viscosities are measured at 25 ° C. unless otherwise noted.

Preferred water-soluble polymer compounds include gelatin, polyvinyl alcohol, partially saponified polymers thereof, polyvinylpyrrolidone, partially saponified polymers thereof, polyacrylic acid, polymethacrylic acid, water-soluble esters thereof, polystyrene sulfonic acid, etc. , Acrylic acid, methacrylic acid, their water-soluble esters, styrene, copolymers obtained from acrylonitrile, etc., and further, methylcellulose, ethylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, carboxyethylcellulose, methoxyethylcellulose, methoxyethylcellulose, etc. Functional cellulose derivatives. The addition amount of these water-soluble polymer compounds is appropriately selected so that the above-mentioned viscosity is obtained. In most cases, the amount is usually 1 to 20 g per liter of the aqueous solution for electroless plating. These polymer compounds may be added alone or in some combination.

Next, a method for forming a metal pattern will be added. The aqueous solution for electroless plating may be applied to the hydrophilic region imagewise formed on the original plate for printing, or the original plate for printing may be immersed in the aqueous solution for electroless plating. Further, in the case of performing the coating, the aqueous solution containing the water-soluble metal compound and the aqueous solution containing the reducing agent are separately coated without being mixed with each other without being mixed and mixed on the substrate to cause precipitation. Good. In particular, when the aqueous solution for electroless plating has a strong reducibility and the life of the treatment solution is short, such a multilayer coating method is advantageous. The temperature at which the thin metal layer is imagewise deposited is in the range from room temperature to 90 ° C. at a suitable temperature for the respective oxidation and reduction system. An appropriate time is also selected for the processing time. Usually one in a few seconds or more
Reaction conditions are selected such that the metal pattern is formed within 0 minutes. If the treatment time is too short, it indicates that the activity of the metal precipitation liquid is too strong. Precipitates. Also, it is unproductive that the sedimentation time is too long. The activity of the metal precipitation liquid can be adjusted by adjusting the concentration of each of the water-soluble metal compound, the complex-forming compound and the reducing agent and the pH of the solution. Next, in the fourth stage, that is, in the third stage, a description will be given of the process of making the hydrophobic region (hereinafter, also referred to as “non-plated region”) hydrophilic in which the electroless plating has not been performed. Since this unplated area remains hydrophobic in the first step, it must be converted to hydrophilic, and this conversion takes place in the fourth step.

In the third stage, a hydrophilic region on which electroless plating has been performed (hereinafter, also referred to as an “electroless plating region”)
Of the two types of metals, the metal forming the thin metal layer and the metal in the non-plated area, the relatively hydrophobic side is the area that receives the ink, but the metal that forms the thin metal layer is It is more hydrophobic and ink-receptive than the metal in the unplated area. However, since this non-plated area is a hydrophobic area,
It is necessary to perform a hydrophilic treatment.

That is, in the fourth step, the area which has been rendered hydrophobic in the first step is made hydrophilic by any means of washing and removing the organic compound and heating to a high temperature at which hydrophilicity is exhibited, and the ink repellency is improved. It is a stage to do.

[0145] Hydrophobization by washing is performed by using water, methanol,
A method of washing the hydrophobic region with a mixed solution of water, a mixed solution of methanol, acetone and water, or the like to remove a layer of an organic compound presumably present on the surface can also be used. However, the organic / inorganic mixed aqueous solution used for this purpose must be a sufficiently water-soluble organic liquid which does not itself have a hydrophobizing effect.

[0146] Hydrophilization by irradiation with actinic light and heating at a high-temperature hydrophilicity expression level is in principle the same as the hydrophilization means used in the second step, except that hydrophilicity is increased in the second step. Although the area was formed imagewise, at this stage, the non-plated area only needs to be made hydrophilic uniformly, and therefore, compared to the scanning type irradiation or heating method such as a laser drawing or a thermal recording head, the uv area is higher. It is easier to perform the irradiation by irradiating the entire surface with actinic light such as light, or by heating the entire surface to a high temperature at which hydrophilicity is exhibited by infrared lamp or electric heating. The reason that the hydrophobic region of the printing original plate changes to hydrophilic by this heating is that the organic component adsorbed on the surface and contributing to the hydrophobicity is converted into the molecular vibration level by the light excitation caused by the active light or by the heating. It is estimated that they are desorbed by excitation or desorbed by decomposition.

By the operation of the fourth step, the non-plated area which has been made hydrophobic for electroless plating while being an area on the original printing plate which should receive the dampening solution recovers its original hydrophilicity. In addition, the electroless plated area has a high physical strength, and in many cases, a printing plate having a high discrimination ability from the recovered hydrophilic non-plated area is formed. After this stage, the printing original plate can be sent to the next printing step.

[Printing] The non-image area (that is, the non-plated area) of the lithographic printing plate prepared by the above-described processing is sufficiently hydrophilic. And the like, or a desensitizing solution containing gum arabic or a starch derivative. As a post-processing when the printing original plate processed according to the present invention is used as a printing plate material, these processings can be used in various combinations. As a method, with a sponge or absorbent cotton impregnated with the surface conditioning liquid, apply on a lithographic printing plate,
A method in which a printing plate is immersed in a vat filled with a surface-conditioning solution and applied, or an automatic coater is used. Further, it is more preferable that the applied amount is made uniform with a squeegee or a squeegee roller after the application. The application amount of the surface conditioning liquid is generally 0.03 to
0.8 g / m ² (dry weight) is appropriate. The lithographic printing plate obtained by such a process is applied to an offset printing machine or the like, or is processed on a printing plate by processing a printing plate according to the present invention, and is used for printing a large number of sheets.

[Recycling of Printing Original Plate] Next, the process of recycling the printing plate after printing will be described. After the printing, the printing plate is washed away with a hydrophobic petroleum-based solvent to remove the adhering ink. Examples of the solvent include aromatic hydrocarbons such as kerosene and isoper as commercially available printing ink dissolving liquids, and in addition, benzol, toluene, xylol,
Acetone, methyl ethyl ketone and a mixed solvent thereof may be used. If the image substance does not dissolve, gently wipe it with a cloth. In some cases, a 1/1 mixed solvent of toluene / Daiclean may be used.

Subsequently, the thin metal layer formed by the electroless plating is removed. This removal treatment is not particularly limited, but a method of eluting and removing the thin metal layer by a chemical oxidation treatment is preferable.

The specific method of the chemical oxidation treatment is not particularly limited, but the printing original plate used in a method such as washing, dipping, or coating with a known oxidizing aqueous solution that oxidizes and dissolves the metal. There is a method of contacting the surface. Particularly preferred oxidizing aqueous solutions are photographic bleaching solutions, reducers,
Diverting and using a known processing solution as a color amplification solution,
Alternatively, it is an oxidizing aqueous solution designed by incorporating constituent components necessary for regenerating a printing plate from among them. The composition of the aqueous solution includes an oxidizing agent for oxidizing the electrolessly plated metal, an auxiliary for increasing the oxidizing potential, and a suitable pH for the oxidizing potential.
PH adjusting agent and buffering agent. Examples of the oxidizing agent include organic complex salts of iron (III) (for example, complex salts of aminopolycarboxylic acids or organic acid salts such as citric acid, tartaric acid, and malic acid), red blood salts, persulfates, hydrogen peroxide, and perboric acid. And percarbonate are preferred.

Of these, amino (III) aminopolycarboxylic acid complex salts, persulfates and hydrogen peroxide are particularly preferred from the viewpoint of metal removal ability and rapidity. Aminopolycarboxylic acids, or salts thereof, useful for forming organic complex salts of iron (III) include ethylenediaminedisuccinic acid, N-
(2-carboxylateethyl) -L-aspartic acid, beta-alanine diacetate, methyl iminodiacetic acid, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid,
Examples thereof include 1,3-diaminopropanetetraacetic acid, propylenediaminetetraacetic acid, nitrilotriacetic acid, and iminodiacetic acid. These compounds are sodium, potassium,
Any of lithium and ammonium salts may be used. These ferric ion complex salts may be used in the form of complex salts or ferric salts such as ferric sulfate, ferric chloride, ferric nitrate, and the like.
A ferric ion complex salt may be formed in a solution by using ferric ammonium sulfate, ferric phosphate or the like and a chelating agent such as aminopolycarboxylic acid. In addition, the chelating agent may be used in excess of forming a ferric ion complex salt.
The addition amount of the oxidizing agent is 0.01 to 2.0 mol / l, preferably 0.3 to 1.0 mol / l.

Preferred auxiliaries for increasing the oxidation potential include metal ion complexing agents and water-soluble salt forming agents such as glycolic acid, succinic acid, maleic acid, malonic acid, citric acid, sulfosuccinic acid, thiosulfuric acid. Alkali metal and ammonium salts of imidazole, dimethylimidazole, 2-
Picolinic acid and the like can be mentioned. The addition amount of these compounds is 0.005 to 3.0 per liter of the processing solution.
Mol is preferable, and more preferably 0.05 to 1.5 mol.

Various known compounds which can adjust the oxidation potential to an appropriate pH, such as a pH adjuster or a buffer, which can oxidize the electroless-plated metal in the pH range and adjust the pH to an appropriate range without damaging the raw material. Can be used. In many cases,
The pH of the oxidizing aqueous solution is preferably from 1 to 7, and particularly preferably from 2 to 5. Hydrochloric acid, sulfuric acid, nitric acid,
Phosphoric acid or the like can be added.

Acetic acid and acetate (eg, sodium acetate, potassium acetate, ammonium acetate, etc.) and bisulfite (eg, ammonium bisulfite, sodium bisulfite) as a buffer or a preservative having a buffering capacity , Potassium bisulfite, etc.), citrates (eg, potassium citrate, sodium citrate, ammonium citrate, etc.) and the like are preferred. When these pH adjusters, buffers and the like are used, the added amount is about 0.01
It is preferred that the content be contained in the range of 1.0 to 1.0 mol / liter. When the electrodeposited metal is silver, a halide compound (for example, sodium bromide, potassium bromide, ammonium bromide, bromide) is added to the oxidizing aqueous solution in order to increase the oxidation potential of silver and to promote the dissolving action. It is also preferable to add lithium, calcium bromide, magnesium bromide, manganese bromide, nickel bromide, cerium bromide, thallium bromide) and thiosulfates (alkali metal salts and ammonium salts). When added, the halide compound is 0.01 to 1.0 mol / L, preferably 0.05 to 0.5 mol / L, and the thiosulfate is
0.01-3.0 mol / L, preferably 0.05-1.
The concentration is 0 mol / L.

The time of immersion in the oxidizing aqueous solution can be selected in a wide range, but is usually about 10 seconds to 5 minutes, preferably about 2 seconds.
0 seconds to 1 minute. The immersion temperature is preferably room temperature,
It can be selected in the range from room temperature to 80 ° C.

The printing plate from which the ink has been removed by washing and the electroless plated thin metal layer has been removed as described above is subjected to the hydrophobic treatment by the above-mentioned method, whereby the hydrophobicity is uniformly restored over the entire plate surface. You. This hydrophobizing operation may be performed at any time after washing and removal of the printing ink and before forming an image-like distribution composed of hydrophilic regions and hydrophobic regions in the next plate-making operation, It is preferable that the recycled printing plate is reused in the next plate-making process, because the influence of the history during storage of the printing plate can be eliminated.

Although the number of reproducible times of the printing original plate according to the present invention has not been completely grasped, it is at least 15 times or more. , Plate material mechanical deformation (strain)
It seems to be restricted by such factors.

As described above, the printing method of the present invention has advantages such as high discrimination between hydrophilicity and hydrophobicity, and improved durability of the printing plate. . As a result, a printing plate excellent in printing quality and printing durability can be easily manufactured with good reproducibility.

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited to these examples. [Example 1] Copper was added to 99.5% by weight of aluminum in the presence of copper.
A 0.30 mm thick roll of a JIS A1050 aluminum material containing 01% by weight, 0.03% by weight of titanium, 0.3% by weight of iron, and 0.1% by weight of silicon is used as a 400 mesh pumice stone (manufactured by Kyoritsu Ceramics). The surface was grained using a 20% by weight aqueous suspension of No. 1 and a rotating nylon brush (6,10-nylon), and then thoroughly washed with water. This was immersed in a 15% by weight aqueous sodium hydroxide solution (containing 4.5% by weight of aluminum) and etched so that the amount of aluminum dissolved was 5 g / m ² , and then washed with running water. Further, it is neutralized with 1% by weight nitric acid, and then, in a 0.7% by weight nitric acid aqueous solution (containing 0.5% by weight of aluminum), a rectangular wave having a voltage of 10.5 volts at the anode and a voltage of 9.3 volts at the cathode. Alternating waveform voltage (current ratio r = 0.90, Japanese Patent Publication No. 58-5)
The electrolytic surface roughening treatment was carried out using an electric current at the time of anode of 160 clones / dm ² using the current waveform described in Examples of Japanese Patent Publication No. 796. After washing with water, it was immersed in a 10% by weight aqueous solution of sodium hydroxide at 35 ° C. to dissolve 1 g / m ^{2 of} aluminum.
And then washed with water. Next, 50
It was immersed in a 30% by weight aqueous sulfuric acid solution at ℃, desmutted, and then washed with water.

Further, a porous anodic oxide film forming treatment was carried out in a 20% by weight aqueous sulfuric acid solution (containing 0.8% by weight of aluminum) at 35 ° C. using a direct current. That is, electrolysis was performed at a current density of 13 A / dm ² , and the anodic oxide film weight was adjusted to 2.7 g / m ² by adjusting the electrolysis time. After washing this support with water,
It was immersed in a 3% by weight aqueous solution of sodium silicate at 70 ° C. for 30 seconds, washed with water and dried. The aluminum support obtained as described above had a reflection density measured by a Macbeth RD920 reflection densitometer of 0.30 and a center line average roughness of 0.58 μm.

Next, the aluminum support was vacuum-deposited.
Put in the device, total pressure 1.5x10 ^-FourTo become Torr
The titanium metal piece is heated under the condition of oxygen gas with a partial pressure of 70%.
Heat and deposit on an aluminum support to remove titanium oxide
A film was formed. The crystal component of this thin film is determined by X-ray analysis.
And the ratio of amorphous / anatase / rutile crystal structure is 1.5 /
6.5 / 2, TiO_Two4000 angstrom thin film
It was Trom. This is wound around the substrate of the plate cylinder 1 and
An original plate for upper printing was used.

Subsequently, the original plate was subjected to a hydrophobic treatment. FIG. 1 shows a hydrophobizing treatment unit used in the present embodiment, in which a liquid organic compound or a solution in which an organic compound is dissolved is applied to the surface of an original plate wound around a plate cylinder 1 to form a coating film of an organic compound. Is a hydrophobization processing unit assembled to form a hydrophobizing unit. Inside the mantle 40 of the processing unit, a container 41 filled with the organic compound liquid 27, a dip roller 42 whose lower part is immersed in the liquid filled in the container to attach and remove the liquid, and oppose the dip roller A reverse roller 43 for receiving an appropriate amount of the liquid taken out, and a coating roller 44 for transferring the liquid adhering to the reverse roller 43 and transferring and applying the liquid to the surface of the original plate. The surface of each roller is provided with a liquid-absorbing coating so that an appropriate amount of liquid can be held.

The container 41 for an organic compound shown in FIG. 1 is filled with benzylamine (organic 140, inorganic 85 in the organic conceptual diagram) as the organic compound liquid 27, and the thickness of the liquid film is reduced to 0.1 by a coating roller. Benzylamine was applied to the surface of the original plate under the condition of micron size to form a hydrophobic surface. Contact angle of contact with water on original plate surface
Using Angle Meter CA-D (manufactured by Kyowa Interface Science Co., Ltd.), the contact angle of the surface with water was measured by the air drop method.
Both parts were between 68 and 71 degrees.

Next, an argon laser device was used as a light source of the active light, and scanning exposure was performed with a light beam having an image-like distribution obtained by modulating a laser light beam with image information. The laser beam irradiation condition is that the oscillation wavelength is 0.35 μm
The beam diameter was 30 μm, and the energy intensity was 50 mW. Contact angle meter CA determines the contact angle of hydrophilic surface of the printing plate after irradiation with water.
When the contact angle of water on the surface was measured by the aerial water droplet method using -D (manufactured by Kyowa Interface Science Co., Ltd.), the irradiation area was set to 7 to 7 as the irradiation surface with a measurable area by increasing the scanning line density. 9
There was between degrees.

(Preparation of Metal Precipitation Nucleus)
Physical development nuclei (palladium sulfide) used in the silver salt diffusion transfer method were used. The preparation method is shown below. (1) Solution A: palladium chloride 3.3 g concentrated hydrochloric acid 20 ml After mixing and dissolving the above, 500 ml of water is added. (2) Solution B: 4.5 g of Na ₂ S.9H ₂ O 1 g of polyvinyl alcohol 2400 ml of water (3) Formation of physical development nuclei Solution B is heated to 50 ° C., and solution A is added with stirring.
After the addition of the solution A, the temperature is lowered to 40 ° C., and the pH is adjusted to 5.0 with NaOH. The generated palladium sulfide nuclei were minutely dispersed uniformly in the solution because of their small size, and did not settle until use.

(Formation of a Thin Metal Layer) The above-mentioned palladium sulfide nucleus dispersion was coated on the above-mentioned image-wise exposed printing plate with a thickness of 50 μm.
It was applied using a bar coater for 0 micron and kept at 40 ° C. for 10 seconds. The coating amount is 0.5 ml / cm ²
Above does not affect the result. After 10 seconds, the coating solution on the surface of the sample was wiped off, and then the following aqueous solution (a) for electroless plating was applied using a bar coater having a thickness of 500 μm, and electroless plating was performed at room temperature for 2 to 4 minutes. .

Aqueous solution for electroless plating (a): A solution obtained by adding ammonium hydroxide (24 mol) and 1 mol of glucose to an aqueous silver nitrate solution (1 mol).

After the contact treatment for performing the above electroless plating, the aqueous solution was flowed away, and the surface of the printing original plate was washed with a 5% methanol / water mixed solution of 0.05N hydrochloric acid. Contact angle meter CA-D (Kyowa Interface Science Co., Ltd.)
The contact angle of the surface with water was measured by the aerial water drop method using the method described above, and it was between 8 and 10 degrees, indicating that the hydrophilicity was restored by washing.

The plate cylinder was used in a single-sided printing machine of Oliver 52 manufactured by Sakurai Co., Ltd., and the dampening water was supplied to the ink / fountain solution supply unit 3 by pure water and the ink was supplied by New Japan Ink and Chemicals, Inc.
Offset printing was performed on 5000 sheets using ampion F gloss 85 ink. Ink was received in the electroless plating area, and a printing surface receiving the dampening solution was formed in the non-plating area. A clear printed matter was obtained from the start to the end, and no damage to the plate cylinder was observed.

Comparative Example 1 In Example 1, the aqueous solution for electroless plating was directly applied to the original printing plate by the above bar coater, without performing the operation of applying the palladium sulfide nucleus dispersion on the original printing plate with a bar coater. The surface of the printing original plate was cleaned in the same manner as in Example 1. After washing, the contact angle of water on the printing plate surface of the non-plated portion was measured in the same manner as in Example 1. The contact angle was between 8 and 10 degrees, indicating that the hydrophilicity was restored by washing. Indicated.

The plate cylinder was subjected to offset printing in the same manner as in Example 1, but the press life and image quality were inferior to those in Example 1. Example 2 The original plate for printing used in Example 1 and the following dispersion liquid of metal deposition nuclei and aqueous solutions I-1 to I-1 for electroless plating
Except that 0 was used, in the same manner as in Example 1, the treatment for providing metal deposition nuclei and the electroless plating were performed at room temperature for 2 to 4 minutes,
The surface of the printing plate was washed in the same manner as in Example 1, and the contact angle with water was measured in the same manner. The contact angle was between 8 and 10 degrees, indicating that the hydrophilicity was restored by the washing.

When printing was performed on this plate cylinder in the same manner as in Example 1, a printing surface was formed in which ink was received in the electroless plating area and dampening water was received in the non-plating area.
From the start to the end, the same clear printed matter as in Example 1 was obtained, and no damage to the plate cylinder was observed.

Preparation of Metal Precipitation Nucleus Dispersion (Colloidal Silver Fine Particles for Yellow Filter) Solution A: 20 g of lime-processed gelatin, 30 g of starch (potato starch) and 40 g of sodium hydroxide were dissolved in 1 liter of water, and the temperature was adjusted to 30 ° C. Adjusted to C. Solution B: 20 g of silver nitrate is dissolved in 1 liter of pure water and 30 °
Adjusted to C. The solution B was rapidly added while the solution A was vigorously stirred, and after the addition, appropriate stirring was further performed for 1 hour. After 50 g of gelatin was added to the mixture, the pH was lowered to 4.0 according to a conventional method, and the mixture was desalted and washed with a naphthalenesulfonic acid / formalin condensate. It was redispersed to obtain a metal precipitation nucleus dispersion. Aqueous solutions for electroless plating I-1 to I-10: Prepare the following silver / ammonia complex salt aqueous solution (a-1) and aqueous alkali solutions (b-1 to b-10) of various reducing agents, and mix them in equal amounts. Thus, an aqueous solution for electroless plating was prepared. Aqueous solution of silver / ammonia complex salt (a-1) 0.1 mol of silver nitrate was dissolved in 800 ml of water, 1 mol of ammonium nitrate was added, the pH was adjusted to 11 with 28% aqueous ammonia, and water was added to make 1 liter. Reducing agent aqueous solution (B-1 to B-10) For each of the reducing agents shown in Table 1, a reducing agent 0.2
5 g equivalents (50 g for sugars and starch) and 60 g of sodium hydroxide (additional equivalents of acid if the reducing agent is an acid) are each dissolved in 800 ml of water, and then water is added to make 1 liter. Aqueous reducing agent (B-
1 to B-10) were prepared.

[0174]

[Table 1] Comparative Example-2 In the above-mentioned Example 2, the aqueous solution for electroless plating was directly applied by the above-mentioned bar coater without performing the operation of applying the metal deposition nucleus dispersion liquid on the original printing plate with a bar coater. The printing plate surface was cleaned in the same manner as in Example 2. After washing, the contact angle of water on the printing plate surface of the non-plated portion was measured in the same manner as in Example 1. The contact angle was between 8 and 10 degrees, indicating that the hydrophilicity was restored by washing. Indicated.

The plate cylinder was subjected to offset printing in the same manner as in Example 2, but the press life and image quality were inferior to those in Example 2. [Example 3] The printing original plate used in Example 1, the following metal deposition nucleus dispersion and aqueous solutions for electroless plating II-1 to II-
7 in the same manner as in Example 1 except that a treatment for providing metal deposition nuclei and electroless plating were performed at room temperature for 2 to 4 minutes, and the surface of the printing original plate was washed in the same manner as in Example 1; When the contact angle was measured, it was between 8 and 10 degrees,
It was shown that washing restored the hydrophilicity.

When printing was performed on this plate cylinder in the same manner as in Example 1, ink was received in the electroless plating area, and a printing surface in which dampening water was received was formed in the non-plating area.
From the start to the end, the same clear printed matter as in Example 1 was obtained, and no damage to the plate cylinder was observed.

Preparation of Metal Precipitation Nucleus Dispersion 20 g of commercially available colloidal silica having a particle size of 20 to 50 nm was dispersed in 1 liter of a 0.1% aqueous solution of dodecylbenzenesulfonic acid, and 5 g of silver nitrate was further added. While stirring vigorously at room temperature, 30 g of potassium hydroxide and glucose 5
g in 1 liter of water was added dropwise over 30 minutes. After the completion of the dropwise addition, the mixture was further stirred for 1 hour, and the pH was adjusted to 7 to 8 by adding an acid.

Aqueous solutions II-1 to II-7 for electroless plating: The following silver nitrate / complex salt aqueous solutions (c-1 to c-7) were prepared.
On the other hand, as an alkaline aqueous solution of a reducing agent, B-1 was prepared in the same manner as in Example 2 and mixed in equal amounts to prepare aqueous solutions II-1 to II-7 for electroless plating. Silver nitrate / complex salt aqueous solution (c-1 to c-7) 0.1 mol of silver nitrate was dissolved in 800 ml of water, 1 mol of the complex salt compound shown in Table 2 was added, and the pH was adjusted to 11 with sodium hydroxide, and then water was added. To 1 liter.

[0179]

[Table 2]

Comparative Example 3 In Example 3 described above, the aqueous solution for electroless plating was directly applied to the original printing plate by the above bar coater without performing the operation of applying the metal precipitation nucleus dispersion to the original printing plate using a bar coater. Then, the printing original plate surface was washed in the same manner as in Example 3. After washing, the contact angle of water on the printing plate surface of the non-plated portion was measured in the same manner as in Example 1. The contact angle was between 8 and 10 degrees, indicating that the hydrophilicity was restored by washing. Indicated. Example 3
In the same manner as in Example 3, offset printing was performed, but the printing durability and image quality were inferior to those in Example 3.

Example 4 A mixture of the original printing plate used in Example 1, the development nucleus dispersion for silver salt diffusion transfer used in Example 1, the following copper / ammonia complex aqueous solution, and a reducing agent aqueous solution In the same manner as in Example 1, except that was used as an aqueous solution for electroless plating, a treatment for providing metal deposition nuclei and electroless plating were performed at room temperature for 2 to 4 minutes, and the surface of the printing original plate was washed in the same manner as in Example 1. When the contact angle with water was measured in the same manner, it was between 8 and 10 degrees, indicating that the hydrophilicity was restored by washing.

When printing was performed on this plate cylinder in the same manner as in Example 1, ink was received in the electroless plating area, and a printing surface in which dampening water was received was formed in the non-plating area.
From the start to the end, the same clear printed matter as in Example 1 was obtained, and no damage to the plate cylinder was observed.

Copper / ammonia complex aqueous solution: copper sulfate 0.1
Was dissolved in 800 ml of water, and 1 mol of ammonium sulfate was added.
Then, water was added to make up to 1 liter. Aqueous reducing agent solution: 50 g of potato starch and 60 g of potassium hydroxide were dissolved in 800 ml of water, and water was added to make 1 liter to prepare an aqueous reducing agent solution.

Comparative Example 4 In Example 4 described above, an aqueous solution for electroless plating was directly applied without performing the operation of applying the metal precipitation nucleus dispersion liquid on the printing original plate. The printing plate surface was washed. After washing, the contact angle of water on the surface of the printing plate of the non-plated portion was measured in the same manner as in Example 3. The contact angle was between 8 and 10 degrees, indicating that the hydrophilicity was restored by washing. Indicated.

The plate cylinder was subjected to offset printing in the same manner as in Example 4, but the printing durability and image quality were inferior to those in Example 4.

[Example 5] Iron, SUS, zinc zinc,
Using copper or nickel, as a metal deposition nucleus dispersion and an aqueous solution for electroless plating, except that the same ones as in Examples 1 to 4 were used, processing was performed in the same manner as in Examples 1 to 4, to prepare a printing plate. Then, when printing was performed in the same manner, the same results as in Examples 1 to 4 were obtained on the respective printing original plates.

Example 6 Barium titanate was converted to a heat-responsive metal oxide having photocatalytic ability by using the same aluminum support having been subjected to the surface roughening treatment and the anodizing treatment used in Example 1. An original plate was produced. That is, the aluminum support was set in a sputtering apparatus, evacuated to 5.0 × 10 ⁻⁷ Torr, heated to 200 ° C., and the Ar / O ₂ became 90/10 (molar ratio). Gas pressure is set to 5 × 10 ^-3 Torr so that
RF power of 200 W was applied to the target of iO ₂ to form a 1 μm thin layer of SiO ₂ . Subsequently, the Ar gas pressure was set to 5 × 10 ⁻³ Torr, and RF was applied to the Si target.
Power of 200 W was applied to form a 1 μm thin film of Si. Subsequently, the Ar gas pressure was set to 5 × 10 ⁻³ Torr,
An RF power of 200 W was applied to a barium titanate sintered target of inch φ to form a barium titanate thin film having a thickness of 3500 °. According to X-ray analysis, this thin film was polycrystalline.

The aluminum support with the barium titanate thin film was wound around the substrate of the plate cylinder and used as a master plate, and heat mode irradiation with an infrared laser was performed to form a hydrophilic image-like region. When the contact angle of water on the surface of the hydrophilic region of the printing original plate after irradiation with water was measured in the same manner as in Example 1, it was between 7 and 9 degrees. For image-like hydrophilicity, use an infrared laser device to produce a maximum output of 500
Using a solid-state infrared laser device of mW, drawing was performed by scanning exposure with the beam width narrowed to 45 microns.

In this case, since the irradiated infrared light is absorbed by Si, this thin layer plays a role of converting light energy into heat energy. That is, since the Si layer generates heat by irradiating infrared rays, the barium titanate layer can be heated. To adjust the heating temperature to the hydrophilic expression temperature range,
The laser output was controlled. Then, in the same manner as in Example 1 using the same metal precipitation nucleus dispersion liquid and an aqueous solution for electroless plating in the image-hydrophilized region as in Example 1, a treatment for providing metal precipitation nuclei and electroless plating were performed. 2-4 at room temperature
Minutes, and the surface of the printing original plate is washed in the same manner as in Example 1.
When the contact angle to water was measured similarly, it was between 8 and 10 degrees, indicating that the hydrophilicity was restored by washing.

When printing was performed on this plate cylinder in the same manner as in Example 1, ink was received in the electroless plating area, and a printing surface in which dampening water was received was formed in the non-plating area.
From the start to the end, the same clear printed matter as in Example 1 was obtained, and no damage to the plate cylinder was observed.

[Examples 7 to 9] Processing for providing metal deposition nuclei and electroless plating were performed in the same manner as in Example 6 using the same metal deposition nucleus dispersion liquid and aqueous solution for electroless plating as in Examples 2 to 4. Was applied at normal temperature for 2 to 4 minutes, and the surface of the printing plate was washed in the same manner as in Example 6. When the contact angle to water was measured in the same manner, it was between 8 and 10 degrees, and the hydrophilicity was restored by the washing. It was shown that. The contact angle of the non-irradiated portion of the infrared laser light with water was 70 to 76 degrees.

When printing was performed on this plate cylinder in the same manner as in Example 6, a printing surface was formed in which ink was received in the electroless plating area and dampening water was received in the non-plating area.
From the start to the end, the same clear printed matter as in Example 6 was obtained, and no damage to the plate cylinder was observed.

Comparative Example 6 In Example 6, the aqueous solution for electroless plating was directly applied to the original printing plate by the above bar coater without performing the operation of coating the metal precipitation nucleus dispersion on the original printing plate with a bar coater. It was applied, and the surface of the printing original plate was washed in the same manner as in Example 6. After washing, the contact angle of water on the surface of the printing plate of the non-plated portion was measured in the same manner as in Example 6. The contact angle was between 8 and 10 degrees, indicating that the hydrophilicity was restored by washing. Indicated. This plate cylinder was subjected to offset printing in the same manner as in Example 1, but the printing durability and image quality were inferior to those in Example 6.

[Comparative Examples 7 to 9] In Examples 7 to 9 described above, the aqueous solution for electroless plating was directly applied to the printing original plate without performing the operation of applying the metal deposition nucleus dispersion with a bar coater. Examples 7 to
The printing original plate surface was washed in the same manner as in No. 9. After washing, the contact angle of water on the surface of the printing plate of the non-plated portion was measured in the same manner as in Examples 7 to 9, and it was between 8 and 10 degrees, and the hydrophilicity was restored by washing. It was shown that.

This plate cylinder was subjected to offset printing in the same manner as in Examples 7 to 9, but the printing durability and image quality were reduced in Examples 7 to 9.
9 was inferior. Example 10 Iron, SUS, zinc, zinc, copper or nickel was used in place of aluminum of the printing plate used in Examples 6 to 9 to prepare a dispersion of metal deposition nuclei and an aqueous solution for electroless plating. Except for using the same components as in Examples 9 to 10, processing was performed in the same manner as in Examples 6 to 9 to prepare a printing plate, and printing was performed in the same manner. Similar results were obtained.

[Example 11] The surface of the printing original plate used for printing in Examples 1 to 10 was coated with a printing ink cleaning liquid Daiclean R (a sales agency; Dainippon Ink and Chemicals, Inc.) and a 1/1 mixed solution of toluene. Was soaked in a waste cloth and washed carefully to remove the ink. Subsequent to the ink washing, the same operation was performed except that a regenerated printing original plate was used in which a thin metal layer was removed from a 1.5 mol / L aqueous solution of hydrogen peroxide with a treatment solution whose pH was adjusted to 2.2 with hydrochloric acid. An image consisting of a thin metal layer was formed on a printing plate by processing in the same manner as in the example, and printing was performed in the same manner.On each printing plate, a clear printed matter similar to that of each example was obtained. No damage to the plate cylinder was observed. Such reproduction processing was effective up to nine times.
Further, in the above embodiment, a printing plate was prepared in the same manner as described above except that the hydrophobic treatment unit shown in FIG. 2 was used in place of the apparatus shown in FIG. When printing was performed, the same results as in the above example were obtained for each printing original plate. FIG. 2 shows a hydrophobizing section provided with an organic compound vapor supply means so as to generate vapor of an organic compound and promote the hydrophobicization of the surface of the printing original plate in an atmosphere containing the vapor. .

In FIG. 2, the organic compound vapor supply means 2
In 9, air is taken in from the air intake port 24 and is led through the cock 25 to the evaporation chamber 26 in which a separatory funnel type glass tube having an inner diameter of about 30 mm is arranged horizontally. The evaporating chamber is filled with an organic compound 27 (shown by oblique lines) so that the volume ratio becomes, for example, 50%.
After a necessary amount of evaporating gas of the organic compound is taken in while the air passes through the inside and the surface of the plate, it is led to the surface of the printing plate on the plate cylinder 1, and drawing is performed in the mixed atmosphere of the air and the evaporating gas. The structure is

The inside of the jacket of the hydrophobizing unit is provided with an evaporation chamber 26, an electric heater 30 for use if necessary to promote evaporation, and a temperature sensor 33 disposed in the evaporation chamber 26 and the jacket inner space. , 32 and a temperature control unit 34 for controlling the inside temperature of the mantle.

[0199]

According to the present invention, the surface of a printing plate having an image forming layer of a metal oxide having a property that the surface becomes hydrophilic by light irradiation and / or a metal oxide having a high-temperature hydrophilicity developing property is obtained. As the hydrophobicity, the surface is illuminated imagewise or heated imagewise at a high hydrophilicity developing temperature to form an imagewise distribution of hydrophilicity and hydrophobicity, and a printing plate having the imagewise distribution Containing a water-soluble metal compound and a reducing compound,
The aqueous solution for electroless plating prepared so that the oxidation potential of the reducing compound is lower (lower potential) than the reduction potential of the water-soluble metal compound is brought into contact with the electroless plating solution, and the hydrophilicity on the printing original plate is reduced. The printing method of forming a printing plate by forming a thin metal layer imagewise in the hydrophilic region having a metal precipitation nucleus on the surface is a method of directly preparing a printing plate without requiring processing such as development. After the printing is completed, the printing plate is removed from the ink and the printing plate is regenerated to be used repeatedly. According to this method, the mechanical strength of the printing plate is enhanced by the thin metal layer formed on the metal precipitation nuclei, so that both printing quality and printing durability can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of one embodiment of a hydrophobic treatment unit provided with a supply and application unit of an organic compound.

FIG. 2 is a diagram showing a configuration of one embodiment of a hydrophobic treatment unit provided with a means for supplying and applying an organic compound vapor.

[Explanation of symbols]

 Reference Signs List 1 plate cylinder 2 hydrophobizing unit 24 air intake 25 cock 26 evaporating chamber 27 organic compound 29 organic compound supply means 30 electric heater 32 temperature sensor 33 temperature sensor 34 temperature control unit 40 jacket 41 container 42 dip roller 43 reverse roller 44 Coating roller

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takashi Nakamura 798, Miyadai, Kaisei-cho, Ashigara-gun, Kanagawa Prefecture Photo Film Co., Ltd. F-term (reference) 2H025 AA02 AA12 AB03 AC01 AD03 BH03 FA12 FA14 2H084 AA14 AA30 CC05 2H096 AA06 BA09 BA16 EA02 FA05 2H113 AA01 AA02 BA05 BB22 DA04 DA07 DA14 DA25 EA02 EA04 FA08 FA29 FA42 2H114 AA04 AA22 AA27 AA30 BA01 BA05 DA05 DA07 DA25 DA78 FA16 GA07 GA31 GA34 GA35 GA36 GA38

Claims (1)

[Claims] (1) contacting a printing original plate having a surface with a metal oxide having a property of making the surface hydrophilic by light irradiation and / or a metal oxide having a high-temperature hydrophilicity developing property with an organic compound; Alternatively, the surface of the original plate is made hydrophobic by heating to a temperature at which hydrophobicity is exhibited, and then the irradiated portion or the heated portion is irradiated by imagewise irradiating the surface with light or imagewise heated at a high temperature at which hydrophilicity is exhibited. To a hydrophilic region to form an image-like distribution of a hydrophobic region and a hydrophilic region, and a water-soluble metal compound and a reducing compound are contained on a printing plate having the image-like distribution. An aqueous solution for electroless plating prepared such that the oxidation potential is lower (lower potential) than the reduction potential of the water-soluble metal compound is brought into contact with the electroless plating aqueous solution. And metal deposition nuclei on the surface Forming a thin metal layer in the hydrophilic region having an image, further applying a hydrophilic treatment to the hydrophobic region, and bringing the printing plate into contact with the ink to form an ink in the region having the thin metal layer. Offset printing method, wherein a printing surface that accepts the image is formed and printing is performed.