JP2000131827A - Original plate for offset printing and offset printing method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an offset printing means by which the surface of printed paper is made almost free from ink stain when an original printing plate using a thin layer of a specified metal oxide and capable of repetitive regeneration and use for a non-treated printing plate is reused. SOLUTION: The original plate for offset printing has a thin layer of a metal oxide selected from TiO2, RTiO3 (R is an alkaline earth metal), AB2-xCxD3-xExO10 (A is H or an alkali metal, B is an alkaline earth metal or Pb, C is a rare earth metal, each of D and E is a group Va or IV metal and (x) is 0-2), SnO2, Bi2O3 and Fe2O3 on the surface. The surface of the thin layer is a rough surface having projecting and recessing parts, and having >=1.0 μm circle conversion arithmetic mean pore diameter of recesses. The original plate is irradiated with active light beams and treated with heat to vary the hydrophilic or lipophilic property of the thin layer on the surface of the original plate to imagewise and the formed printing surface is used for printing. The original printing plate is regenerated by heating and used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to the field of general light printing,
More particularly, the present invention relates to offset printing, and more particularly to a novel offset printing method and a printing plate capable of easily producing a printing plate. More specifically, the present invention relates to an offset printing method that enables repeated use of a printing original and a printing original.

[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. When the ink carrying plate surface is brought into direct contact with the surface to be printed or indirectly via an intermediate called 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 applied thereon. In PS plates, the aluminum substrate is used as a support, the surface is grained, anodizing and other processes are applied to enhance the ink receiving ability and the ink repulsion of the non-image areas, thereby improving the printing durability and printing. Means have been taken to refine the surface. Accordingly, offset printing has been provided with characteristics such as printing durability and high definition of the printing surface in addition to simplicity. However, with the spread of printed matter,
There is a demand for further simplification of the offset printing method, and many simple printing methods have been proposed.

Representative examples include the Copyrapid offset printing plate commercially available from Agfa-Gevaert, and US Pat.
This is a printing method based on printing plate production by a silver salt diffusion transfer method, which is also disclosed in JP-A-11-656 and JP-A-7-56351, and can produce a transfer image in one step. Since the image is lipophilic and can be used as a printing plate as it is, it is practically used as a simple printing method. However, although simple, this method also requires a diffusion transfer development step using an alkaline developer. There is a demand for a simpler printing method that does not require a developing step with a developer.

[0005] In view of the above background, there has been developed a method of manufacturing a simple printing plate in which image exposure is performed and then plate making is performed without performing development using an alkali developing solution. This simplified print version
Since the development step is omitted, it is also called a non-process printing plate, and many improvement methods have been proposed. For example, image formation by thermal destruction of an irradiated portion on an image recording surface by imagewise exposure, image formation by lipophilicity (heat mode curing) of the irradiated portion by imagewise exposure, and lipophilicity of the irradiated portion, Means based on various principles, such as a method based on light mode curing, a change in surface properties due to photolysis of a diazo compound, and a heat mode fusion thermal transfer of an image area, have been proposed.

The technique disclosed as the simple offset printing method includes US Pat. No. 3,506,779.
No. 3,549,733 and No. 3,574,65
No. 7, No. 3,739,033, No. 3,832, 9
No. 48, No. 3,945,318, No. 3,962,
Nos. 513, 3,964,389 and 4,03
No. 4,183, No. 4,081,572, No. 4,6
Nos. 93,958, 731,317 and 5,23
No. 8,778, No. 5,353,705, No. 5,3
U.S. Patents Nos. 85,092 and 5,395,729 and European Patent 1068.

[0007] These do not require a developing solution for plate making, but the difference between the lipophilic region and the hydrophilic region is insufficient, so that the image quality of the printed image is poor, the resolution is poor, and the sharpness is excellent. Printed screen is difficult to obtain, the mechanical strength of the image surface is inadequate and easily scratched, which necessitates the provision of a protective film, which rather impairs simplicity and durability to withstand long-time printing Is inadequate, etc., indicating that simply eliminating the alkali development step is not practical. Thus, the realization of a printing plate making method which has various characteristics required for printing and which can easily produce a printing plate has been strongly demanded, but has not been satisfied yet.

On the other hand, along with the simplification of the printing method typified by the unprocessed printing plate, if the used printing original plate can be easily regenerated and reused, the cost and the waste can be reduced. Needless to say, it is advantageous in terms of both environmental suitability, but the recycling of the original printing plate is a problem with various difficulties, and has been hardly studied in the past. It only discloses a special master material called ceramic. However, the light sensitivity of zirconia is insufficient, and the effect of converting light from hydrophobic to hydrophilic is insufficient, so that the discriminability between the image area and the non-image area is insufficient.

In view of the above situation, the present inventors belong to groups 2, 4, and 5 of the periodic table as printing plates for unprocessed printing plates which are excellent in simplicity, economy and environmental suitability and can be easily used. A printing original plate using a thin layer of an oxide of a specific metal, for example, titanium oxide, and a printing method using the original plate are disclosed in Japanese Patent Application Nos. 9-248761, 9-258784 and 9-272804. , Japanese Patent Application No. 9-308822,
Japanese Patent Application No. 9-308823, Japanese Patent Application No. 9-313740
No., Japanese Patent Application No. 9-348077, Japanese Patent Application No. 9-34807
No. 8, each proposal. This original plate is an excellent printing original plate satisfying the three characteristics of simplicity, economy, and environmental suitability. However, when used repeatedly, the degree of ink stain on the printing paper surface is lower than that of the printing paper surface using the new printing original plate. Also proved inferior. Therefore, it is desired to establish a method for maintaining the print quality of the printing paper surface in the first printing, with less ink smear even after repeated use.

[0010]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to improve a reproducible printing original plate for an unprocessed printing plate using the above-mentioned specific metal oxide thin layer. More specifically, it is an object of the present invention to provide an offset printing means which has a small amount of ink stains on the printing paper surface at the time of reuse, maintains print quality even when printing base plates are repeatedly used, and can therefore increase the number of times of repetitive use.

[0011]

Means for Solving the Problems In order to achieve the above object, the present inventors have intensively investigated the causes of ink stains, and the cause is that even if the ink on the used printing plate is washed. It was found that the ink was not completely removed from the plate, and based on this fact, a search was made for a means for preventing the ink from remaining on the plate, and the present invention was reached. That is, the present invention is as follows.

1. TIO ₂ , RTiO on the surface of the substrate
₃ (R is an alkaline earth metal atom), AB _{2- x} C _x D _3-x
Ex 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 Group 5A element of the periodic table, and E is 4
A printing element having a thin layer comprising at least one of a metal atom belonging to group elements, x represents an arbitrary value of 0 to 2), SnO ₂ , Bi ₂ O ₃ and Fe ₂ O ₃ , The surface of the thin layer has at least 1.
An original plate for offset printing characterized by a rough surface having irregularities of 0 micron

2. After changing the degree of hydrophilicity and lipophilicity of the thin layer provided on the substrate surface by irradiation with actinic light and heat treatment in an image-like manner, the thin layer is brought into contact with a printing ink,
The lipophilic portion is a printing plate for forming the printing surface that has received the ink, and after the ink remaining on the printing plate surface after washing is removed by washing, the surface of the printing plate is heated to 80 ° C. or more. 2. The original plate for offset printing as described in 1 above, wherein the original plate can be returned to a state before use and used repeatedly.

3. 3. The printing original plate according to claim 1 or 2, which is irradiated with actinic light and heat-treated to change the degree of hydrophilicity and lipophilicity of the thin layer on the surface of the original plate imagewise, and then printing the thin layer. After the printing, the lipophilic portion forms the printing surface that has received the ink, and performs printing.After the printing is completed, the ink remaining on the printing plate surface is washed and removed.
An offset printing method comprising repeatedly using the printing original by heating the surface of the original to 80 ° C. or higher and returning the original to a state before use.

4.1) A step of irradiating a thin layer on the surface of the printing original plate with the entire surface with actinic light to make the entire thin layer hydrophilic.
A step of imagewise heating the thin layer surface to change the heated portion to lipophilic; 3) contacting the thin layer surface with a printing ink to form a printing surface in which the lipophilic portion has received the ink; And offset printing, 4) after printing,
Repeating the steps of washing and removing the ink remaining on the surface of the thin layer and 5) heating the surface of the thin layer to 80 ° C. or more to return the entire thin layer to a lipophilic state, in order. 3. The offset printing method as described in 3 above, wherein the offset printing method is used.

5.1) A step of irradiating the thin layer on the surface of the printing original plate with the entire surface by activating light to make the entire thin layer hydrophilic.
A step of irradiating the thin layer surface imagewise with light-heat converting radiation to change the irradiated portion to lipophilic; 3) bringing the thin layer surface into contact with a printing ink to form a lipophilic portion; Performing offset printing by forming a print surface that has received ink, 4) washing and removing ink remaining on the thin layer surface after printing is completed, and 5) heating the thin layer surface to 80 ° C. or more. The step of returning the entire thin layer to a lipophilic state by successively performing the above steps to repeatedly use the printing original plate.

6.1) A step of imagewise irradiating the thin layer on the surface of the printing original plate with actinic light to change the irradiated portion to hydrophilicity, 2) bringing the thin layer surface into contact with a printing ink, A step of performing offset printing by forming a printing surface in which the oily portion has received the ink, 3) a step of washing and removing the ink remaining on the thin layer surface after printing is completed, and 4) a temperature of 80 ° C. or higher for the thin layer surface The method according to the above item 3, wherein the printing original plate is repeatedly used by sequentially performing the steps of: heating the entire thin layer to a lipophilic state.

[7] The offset printing method according to any one of the above items 3 to 6, wherein the active light used for the imagewise irradiation is a laser beam light.

The present invention is based on an unprocessed printing plate precursor using a thin layer of the above-mentioned specific metal oxide for the printing plate surface and a printing method based thereon, and is an improved invention in which printing stains during repeated use are reduced. is there. The basic technology, TIO ₂ on the surface of the substrate, 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 alkali Earth metal atom or lead atom, C is a rare earth atom, D is a metal atom belonging to Group 5A element of the periodic table, E is a metal atom belonging to the same Group 4 element, x
Represents an arbitrary numerical value of 0 to 2), SnO ₂ , Bi ₂ O ₃
And using a printing plate precursor having at least one consisting of a thin layer of Fe ₂ O _3, changing the degree of hydrophilicity-lipophilicity thin layer provided on the substrate surface by irradiation and heat treatment of the active light imagewise Thereafter, the thin layer was brought into contact with a printing ink to wash and remove the ink remaining on the printing plate surface after the printing was completed, in which the lipophilic portion was the printing base plate that formed the printing surface that received the ink. After that, the original plate surface is 80 °
This is an original plate for offset printing which can be repeatedly used by returning the original plate to a state before use by heating to C or more, and a printing method using the same.

That is, a thin layer of a specific metal oxide has the property of changing its surface property to hydrophilic upon irradiation with actinic light, and the property of the surface changed by heat. It has the property of returning to hydrophobicity, and these two properties are applied to discrimination of ink receptivity and repellency to produce a non-processed printing plate for offset printing.
The used printing plate is also reproduced on the original printing plate by utilizing the above-mentioned heat change characteristics of the surface physical properties. As described above, the above basic technology has been filed in Japanese Patent Application No. 9-248761.

An improvement of the present invention over the above-mentioned basic technology is that the surface of the thin layer on the substrate is a rough surface having irregularities having a circular arithmetic mean pore diameter of at least 1.0 micron of the concave portion. The essence of the present invention is that when a used printing plate is washed with an ink cleaning agent, the remaining ink is firmly adsorbed to fine portions of the uneven structure on the surface of the printing plate and does not dissolve in the cleaning agent. Based on the elucidation of the existence, there is the elimination of particularly fine structures with surface irregularities. The rough surface is necessary to increase the ability of the ink repellent portion on the plate surface to retain the dampening solution during printing.However, it is not necessary that the surface be very fine. It is sufficient if there are large irregularities. The fineness of the concavo-convex structure can be represented by a circle-converted average pore diameter obtained by taking an arithmetic mean value of the diameter of the recess (referred to as a circle-converted hole diameter), considering one recess as a circular depression. In the present invention, the object of the present invention has been attained by using a printing original plate having a circular layer average pore diameter of 1 micron or more on the surface of the thin layer. The fineness of the irregularities on the printing plate surface
The adjustment is performed by adjusting the unevenness of the printed board surface. Since the thin layer is extremely thin, the unevenness of the substrate is directly reflected.

[0022]

Embodiments of the present invention will be described below in detail. In the following description, the specific metal oxide described in 1 above used in the present invention is referred to as "photocatalytic metal oxide". Before discussing the details, it is important to mention the terminology used in this specification.The term "active light" means that when a photocatalytic metal oxide is absorbed, it is excited to change its surface to hydrophilic. This is the light to be emitted, and details such as its light source and wavelength will be described later. “Imagewise exposure” is exposure in which the illuminance of the light receiving surface is distributed in an image form.
“Thin film” and “thin layer” are used synonymously.

[Substrate] First, a "roughened" substrate that exhibits the effects of the present invention will be described. Preferred substrates are aluminum or SU, which is less likely to corrode on the printing plate.
It is a stainless steel such as an S plate, a nickel plate or a copper plate, and a flexible metal plate can be used. Among them, an aluminum plate which has good dimensional stability and is relatively inexpensive is particularly preferable. Suitable aluminum plates are a pure aluminum plate and an alloy plate containing aluminum as a main component and containing 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, titanium and the like. The content of the foreign element in the alloy is at most 10% by weight or less. Aluminum which is particularly preferred 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 support used in the present invention is approximately 0.05 mm to
It is about 0.6 mm, preferably 0.1 mm to 0.4 mm.
Particularly, an aluminum plate or a copper plate is suitable as the substrate. Hereinafter, a method of surface roughening of an aluminum plate will be described. However, even with other substrates, if the degree of surface roughening is within the range specified in the present invention, it is possible to reduce ink stains when the printing original plate is repeatedly used. .

Usually, the printed substrate has a roughened substrate surface to enhance the dampening water retention property of the ink repellent area in order to enhance the discriminating ability between the ink receiving area and the ink repellent area. Roughening is a combination of irregularities with a large period, that is, irregularities with a long distance between concave and convex portions, irregularities with a medium distance between concave and convex portions, and small-period irregularities with concave and convex portions contacting at extremely short intervals. This combination enhances the stable holding function of the dampening solution. An aluminum substrate for a general-purpose PS plate is covered with fine irregularities having an average circle-equivalent diameter of 0.05 to 0.5 μm, and has a large period (also called a large wave) and a medium period (also called a medium wave). ) Are superimposed on it. However, in the present invention, in order to prevent ink contamination when the original plate is repeatedly used, fine irregularities, that is, irregularities with a small period are not provided on the aluminum substrate. It is limited to those on the micron level, that is, medium to long periods.

The medium to long period irregularities can be formed on the substrate by a known method. For example, long-period irregularities are formed by mechanical roughening described later, and medium-period irregularities are also formed by electrolytic roughening described later.

The aluminum plate is subjected to the following surface treatment. This pretreatment is typically performed by removing the rolling oil on the aluminum plate surface with a solvent such as trichlene or a surfactant, or exposing the clean aluminum plate surface with an alkali etching agent such as sodium hydroxide or potassium hydroxide. is there. Specifically, as the solvent degreasing method, gasoline, kerosene, benzene, solvent naphtha, a method using a petroleum solvent such as normal hexane, trichloroethylene,
Methylene chloride, perchlor ethylene, 1,1,1
-There is a method using a chlorine-based solvent such as trichloroethane. Examples of the alkali degreasing method include a method using an aqueous solution of a soda salt such as sodium hydroxide, sodium carbonate, sodium bicarbonate, and sodium sulfate; sodium orthosilicate, sodium metasilicate, sodium disilicate, sodium silicate, and the like. A method using an aqueous solution of a silicate, a method using an aqueous solution of a phosphate such as sodium primary phosphate, sodium tertiary phosphate, sodium dibasic phosphate, sodium tripolyphosphate, sodium pyrophosphate, sodium hexametaphosphate, and the like can be given. When using the alkaline degreasing method, depending on the treatment time and the treatment temperature, there is a possibility that the aluminum surface may be dissolved.
It is necessary to avoid the dissolution phenomenon. As the degreasing treatment with a surfactant, an aqueous solution of an anionic surfactant, a cationic surfactant, a nonionic surfactant, and an amphoteric surfactant is used, and various commercially available products can be used. As the degreasing method, a dipping method, a spraying method, a method of rubbing a liquid or the like with a liquid or the like can be used. Ultrasonic waves may be used for the dipping or spraying method. Regarding the degreasing treatment, for example, JP-A-2-26793 can be referred to.

Next, it is desirable to perform a mechanical roughening treatment. The mechanical surface roughening is a roughening method for forming large-period irregularities, and includes a method such as transfer, brushing, and liquid honing. Various methods can be used as a transfer method for pressing the uneven surface against the aluminum plate. That is, the above-mentioned JP-A-55-74 is disclosed.
No. 898, JP-A-60-36195, JP-A-60-2
In addition to JP-A No. 03496, Japanese Patent Application No. 4-175945, in which transfer is performed several times, and Japanese Patent Application No. 4-204,235, in which the image is elastic, are also applicable. It is. In addition, electric discharge machining, shot blast,
Using laser, plasma etching, etc., repeat transfer using a roll with fine irregularities etched, or contact the surface with irregularities coated with fine particles to the aluminum plate, and then multiple times from there Apply pressure repeatedly,
An uneven pattern corresponding to the average diameter of fine particles may be repeatedly transferred to the aluminum plate a plurality of times. Japanese Patent Application Laid-Open No. 3-86 describes a method for imparting fine irregularities to the transfer roll.
No. 35, JP-A-3-66404, JP-A-63-650
No. 17, each publication is publicly known. Further, fine grooves may be cut on the roll surface from two directions by using a die, a cutting tool, a laser, or the like, so that the surface may be provided with square irregularities. The roll surface may be subjected to a known etching process or the like, so that the formed square irregularities are rounded. Of course, quenching, hard chrome plating or the like may be performed to increase the surface hardness.

FIG. 1 is a schematic view showing an example of a mechanical roughening process using a brush. A work plate 101 such as an aluminum plate is supported by support rollers 107 and run in the direction of the arrow. The polishing slurry 103 is evenly sprayed on the surface of the plate 101 to be processed, and the brush roll 102 is rotated on the surface to perform a mechanical roughening process. In this example, the polishing slurry is sprayed and the surface is roughened by a brush roll.
I go in several places. When a brush is used, the flexural modulus is 10,000 to 40,000 kg / cm ² , preferably 15,000 to 35,000 kg / cm ² , and the bristle strength is 500 g or less, preferably 400 g or less. It is preferable to use an abrasive having a particle size of 20 to 80 μm, preferably 30 to 60 μm, using brush bristles. The material of the brush preferably has the above-mentioned mechanical strength, and may be used other than the above-mentioned mechanical strength. For example, it can be appropriately selected from synthetic resins and metals. As a synthetic resin,
Examples thereof include polyamide such as nylon, polyolefin such as polypropylene, polyester such as polyvinyl chloride and polybutylene terephthalate, and polycarbonate. Examples of the metal include stainless steel and brass.

Also, the material of the abrasive is preferably in the above-mentioned particle size range, and the material is not limited, and alumina, silica, and silica which have been conventionally used for mechanical surface roughening treatment are used.
It is selected from silicon carbide, silicon nitride and the like. The mechanical surface-roughening treatment is performed by pressing the roll brush having the brush bristles at a high speed while pressing against the surface of the aluminum plate and supplying the abrasive to the roll brush. At this time, the number of rotations of the roll brush, the pressing force, the supply amount of the polishing material, and the like are not particularly limited. As an apparatus suitable for the mechanical roughening, for example, Japanese Patent Publication No. Sho 50-40047
Can be cited.

After the mechanical surface roughening treatment, the aluminum surface is subjected to a chemical etching treatment with an alkaline solution having a pH of 11 or more, preferably pH 13 or more, for the purpose of smoothing and equalizing the aluminum plate. FIG. 2 is a schematic view showing an example of a step of performing a chemical etching treatment on an aluminum surface. An aluminum plate 222 is passed through an etching treatment tank 211 by a pass roll 202 and a nip roll 201, and a liquid preparation is performed in the treatment tank. The treatment solution (etching solution mainly containing sodium hydroxide) is sprayed on the alkaline solution in the tank 205 uniformly over the width direction of the aluminum plate 222 by the spray 203 from the introduction pipe 212 by the solution sending pump 204 (P). Perform etching.

The processing liquid is prepared in a liquid preparation tank 205, and the prepared processing liquid is supplied by a liquid supply pump 204 using a liquid supply pipe 21.
2 to the spray 203. The processing liquid from the liquid preparation tank further passes through the liquid supply pipes 212 ′ and 212 ″ branched from the liquid supply pipe 212, and is passed through the diffusion tank 20.
6 or the liquid can be sent to the precipitation tank 207 by using the pump 204. The amount and timing of liquid supply can be adjusted by operating a valve (not shown) provided in the middle of the pipe.

The liquid preparation tank and the etching tank are connected to the liquid supply pipe 2
12 and a return liquid pipe 213, and the processing liquid is circulated between them. The concentration of the etching solution is such that sodium hydroxide solution and water are supplied to the processing solution in the liquid preparation tank from the supply pipes 200 and 201, respectively. In the diffusion dialysis tank 206, about 70% of the processing solution sent is supplied. Is recovered as a sodium hydroxide solution, and the dialysis waste liquid, which has become a supersaturated sodium aluminate solution by dialysis in a diffusion dialysis tank, is passed through a transparent waste liquid feed pipe 215 to form a precipitation tank 2.
The concentration and the composition are controlled by an operation such as sending to the system 07 to remove aluminum ions from the system. Further, water can be added to the diffusion dialysis tank from the liquid supply pipe 214 in order to supply evaporated water.

The amount of etching in the chemical etching treatment is 3 g / m ² or more and 25 g / m ² or less, preferably 3 g / m ² or less.
g / m ² or more and 15 g / m ² or less. If the etching amount is less than 5 g / m ² , the unevenness formed by the mechanical surface roughening treatment cannot be smoothed, and uniform pits cannot be generated in the subsequent electrolytic treatment. On the other hand, the etching amount is 25 g /
If it exceeds m ² , the irregularities disappear. Examples of usable alkaline solutions include aqueous sodium salt solutions such as sodium hydroxide, sodium carbonate, sodium bicarbonate, and sodium sulfate; and silicic acids such as sodium orthosilicate, sodium metasilicate, sodium disilicate, and sodium silicate. Salt aqueous solutions, aqueous solutions of phosphates such as sodium phosphate monobasic, sodium phosphate dibasic, sodium tertiary phosphate, sodium tripolyphosphate, sodium pyrophosphate, sodium hexametaphosphate and the like can be given. The processing conditions include a concentration of the alkaline solution of 0.01% to 50% by weight, a liquid temperature of 20 ° C to 90 ° C, and a time of 5 seconds to 5 minutes.
It is appropriately selected so that the above etching amount is obtained.

When the surface of the aluminum plate is chemically etched with the above alkaline solution, an insoluble residue, ie, a smut, is formed on the surface of the aluminum plate. Therefore, the smut is removed using an acidic solution having the same composition as the acidic solution used in the electrolytic surface roughening treatment described later. Preferred treatment conditions are a liquid temperature of 30 to 80 ° C. and a time of 3 seconds to 3 minutes.

Next, the aluminum plate thus treated is subjected to electrolytic surface roughening treatment. In the electrolytic surface roughening treatment in the present invention, it is preferable to perform first and second electrolytic treatments using an alternating waveform current in an acidic solution before and after the cathodic electrolytic treatment. By the cathodic electrolysis, a smut is generated on the surface of the aluminum plate, and hydrogen gas is generated to enable more uniform electrolytic surface roughening. First, the first and second electrolytic surface roughening treatments using an alternating waveform current in an acidic solution will be described. In this electrolytic surface roughening treatment, the first treatment and the second treatment may be performed under the same conditions, or may be different in a preferable range of the processing conditions.

FIG. 3 is a schematic view showing an example of a step of performing electrolytic surface roughening treatment on an aluminum support by first and second electrolytic surface roughening treatments. In FIG.
Is an aluminum support, and this aluminum support 3
In FIG. 01, reference numeral 301a denotes a front surface (a surface to be subjected to electrolytic surface roughening treatment first), and 301b denotes a back surface (a surface to be subjected to electrolytic surface roughening treatment later). Further, reference numeral 302 denotes a first surface-side surface roughening treatment device for electrolytically roughening the surface 301a of the aluminum support 301, and reference numeral 303 also denotes a second surface side for electrolytically roughening the surface 301a of the aluminum support 301. The surface roughening treatment device 304 is an aluminum support 30
1 is a back surface roughening treatment apparatus for electrolytically roughening the back surface 301b of the first side. These surface-side roughening devices 302, 3
03 and the back side surface roughening apparatus 304 are provided with a pair of arc-shaped main electrodes 306 connected to an electrolytic cell 305 via an AC power supply (not shown), respectively. Drum roll 3 rotatable above 306
07 is arranged. The space between the main electrode 306 and the drum roll 307 is filled with the electrolytic solution 8.

Further, the first surface side roughening device 302
A plurality of pass rolls 9 are arranged at predetermined locations between the second front side surface roughening device 303 and the back side surface roughening device 304 to form a traveling path for the aluminum support 201. The traveling path between the second front surface roughening device 303 and the back surface roughening device 304 is such that in the back surface roughening device 304, the front surface 301a is in contact with the drum roll 307 and the back surface 301b is There is a reversing path 310 for reversing the aluminum support 301 so as to be immersed in the electrolyte 308. And, this reversing road 310
Are provided with a plurality of spray devices 311 for spraying the electrolyte aluminum support 301.

In order to manufacture an aluminum support by the above-described apparatus, each of the surface roughening apparatuses 302, 303, 30
4 and the aluminum support 301 is run while energizing each of the main electrodes 306. Then, the aluminum support 301 has its front surface 301a roughened continuously by the first front surface roughening device 302 and the second front surface roughening device 303. The aluminum support 301 whose front side 301a is roughened passes through the reverse running path 310, the front side 301a is in contact with the drum roll 307 of the back side roughening device 304, and the back side 301b is an electrolytic solution. 8 is sent to the back surface roughening device 304 in a reversed state. And this reversing road 31
During traveling on the aluminum support 301, the electrolyte is sprayed from the plurality of spray devices 311 to keep the aluminum support 301 wet.

This electrolytic surface roughening treatment is carried out, for example, in
-28123, British Patent No. 896563 can be used. This electrolytic surface roughening treatment uses a sinusoidal alternating current, but it may be performed using a special waveform as described in Japanese Patent Application Laid-Open No. 52-58602. Further, a waveform described in JP-A-3-79799 can also be used. JP-A-55-158298, JP-A-56-28898, JP-A-52-58602, JP-A-52-152302, JP-A-54-85802, JP-A-60-190362, JP-A-58-120531 JP-A-63-176178, JP-A-3-26010
0, JP-A-3-253600, JP-A-4-72079,
The methods described in JP-A-4-72098, JP-A-3-267400 and JP-A-1-141994 can also be applied. . As the frequency, in addition to the above, those proposed for electrolytic capacitors can be used. For example, there are U.S. Pat. Nos. 4,276,129 and 4,676,879.

Examples of the acidic solution as an electrolytic solution include nitric acid, hydrochloric acid and the like, as well as US Pat.
4661219, 4618405, 46262
8, 4,600,482, and the electrolytic solution described in the specification can also be used. The concentration of the acidic solution is preferably 0.5 to 2.5% by weight, but considering the use in the above-described smut removal treatment,
0.7-2.0% by weight is particularly preferred. The liquid temperature is 2
0-80 degreeC, especially 30-60 degreeC are preferable.

Various electrolytic cells and power sources have been proposed, but are described in US Pat.
123400, JP-A-57-59770, JP-A-53-570
12738, JP-A-53-32821, JP-A-53-3283
2822, JP-A-53-32323, JP-A-1-230
800 and JP-A-3-257199. In addition to the above-mentioned patents, various proposals have been made. For example, JP-A-52-58602 and JP-A-52-58602
-152302, JP-A-53-12738, JP-A-53-12738
12739, JP-A-53-32821, JP-A-53-328
32822, JP-A-53-32833, JP-A-52-1
33845, JP-A-53-149135, JP-A-54-54
Of course, those described in each of the 146234 publications can also be applied.

This electrolytic treatment is carried out at an anode electricity amount of 30 to 400.
C / dm ^2, preferably at 80~300C / dm ^2. If the amount of anode electricity is less than 30 C / dm ² , uniform pits will not be generated, and the circular equivalent hole diameter will be excessively small. On the other hand, if it exceeds 400 C / dm ² , the pit equivalent circle diameter becomes too large.

During the first and second electrolytic surface roughening treatments, the aluminum plate is subjected to a cathodic electrolytic treatment. By this cathodic electrolysis, smut is generated on the surface of the aluminum plate, and hydrogen gas is generated, so that more uniform electrolytic surface roughening is possible. This cathodic electrolysis treatment is carried out in an acidic solution at a cathodic charge of 3 to 80 C / dm ² , preferably 5 to 30 C / dm ² .
/ Dm ² . Cathode in the amount of electricity is less than 3C / dm ^2, insufficient smut adhesion amount, whereas if it exceeds 80C / dm ^2, not desirable smut adhering amount is excessive. Further, the electrolytic solution may be the same as or different from the solution used in the first and second electrolytic surface roughening treatments.

After the second electrolytic surface roughening treatment, the aluminum plate is subjected to a second chemical etching treatment using an alkaline solution having a pH of 11 or more. The alkaline solution having a pH of 11 or more used in the second chemical etching treatment may be the same as or different from the alkaline solution used in the first chemical etching treatment. However, unlike the first chemical etching process, the etching amount is 0.1 to 8 g / m ² , preferably 0.2 to 8 g / m ² .
3.0 g / m ² , more preferably 0.5 to 1.5 g / m ^2
2 If the etching amount is less than 0.1 g / m ² , the pit end obtained by the electrolytic treatment cannot be smoothed, while if it exceeds 8 g / m ² , the pits disappear.

Since a smut is generated by the above chemical etching treatment, the smut is removed from the aluminum plate using a solution mainly containing sulfuric acid. Here, the solution mainly composed of sulfuric acid means not only a solution of sulfuric acid alone, but also phosphoric acid, nitric acid,
It is a mixed solution obtained by appropriately mixing chromic acid, hydrochloric acid and the like.
For the removal of the smut using a solution mainly containing sulfuric acid, for example, JP-A-53-12739 can be referred to. Further, an alkali treatment may be combined, and for example, JP-A-56-51388 can be referred to. Further, JP-A-60-8091, JP-A-63-176
188, JP-A-1-38291, JP-A-1-12738
9, JP-A-1-188699, JP-A-3-17760
0, JP-A-3-126891, JP-A-3-191100
The methods described in each publication can be used in combination.

Next, it is preferable to form an anodic oxide film on the surface of the aluminum plate. Any known method may be used for the anodizing treatment. In order to carry out anodic oxidation, for example, a solution having a sulfuric acid concentration of 50 to 300 g / l and an aluminum concentration of 5% by weight or less is used as an electrolytic solution, and an anodized film is formed by passing an electric current using an aluminum plate as an anode.
The solution may contain phosphoric acid, chromic acid, oxalic acid, sulfamic acid, benzenesulfonic acid, and the like. The amount of the formed oxide film is 1.0 to 5.0 g / m ² , particularly 1.5 g / m ² .
Is preferably to 4.0 g / m ^2. The anodizing treatment conditions vary depending on the electrolytic solution used, so cannot be said in general, but generally, the concentration of the electrolytic solution is 1 to 10.
80% by weight, liquid temperature 5-70 ° C, current density 0.5-60A
/ Cm ² , voltage 1 to 100 V, electrolysis time 15 seconds to 50 minutes, and is adjusted to have the above-mentioned coating amount.
As the electrolysis apparatus, Japanese Patent Application Laid-Open Nos. 48-26638 and
7-18739 and JP-B-58-24517. Also, Japanese Patent Application Laid-Open Nos. 54-8113, 57-47894, 6-207299, and 5
-24377, JP-A-5-32083, JP-A-5-12
5597 and JP-A-5-195291 can also be used.

The method for roughening the substrate has been described above. Next, a method of measuring the roughness of the substrate surface will be described. AFM (atomic force microscope, Atomic For
ce Microscope) is used. AFM includes SP13700 manufactured by Seiko Electronic Industry Co., Ltd. Measurement is 1
An aluminum plate sample cut to the size of cm square is set on a horizontal sample stage on a piezo scanner, and the cantilever approaches the sample surface. Then, the unevenness of the sample is captured by the displacement of the piezoelectric element in the Z direction. The piezo scanner uses an XY 150 μm, Z10 μm, and scanable one. The cantilever is SI-DF20 manufactured by NANOPROBE.
With a resonance frequency of 120 to 50 kHz and a spring constant of 12 to 20
N / m, DFM mode (Dynamic Force Mode)
Measure with Also, the reference plane is obtained by correcting the slight inclination of the sample by least-squares approximation of the obtained three-dimensional data.

In the present invention, the roughness (fineness) of the medium wave is important, but the large wave is also superimposed. In the measurement of the undulation of the large waves, the average surface roughness, and the inclination, the measurement was performed in four visual fields of 120 μm square, that is, 240 μm square. The resolution in the XY directions was 1.9 μm, the resolution in the Z direction was 1 nm, and the scan speed was 60 μm / sec. The pitch of the undulation of the large wave is calculated by performing frequency analysis on the three-dimensional data.

The measurement of the pit diameter of the medium wave is performed in a measurement area of 25 μm.
The measurement was performed in four fields of m angles, that is, 50 μm square, and X
Resolution in Y direction is 0.1 μm, resolution in Z direction is 1n
m, scan speed is 25 μm / sec, and the diameter is determined from the edge of the pit.

The undulation of the aluminum plate is preferably a grain in which a large wave having an average pitch of 5 to 30 μm and a grain of 1.0 to 5 μm are superposed, and in particular, a grain of 1-2 μm is uniformly formed on the entire surface. It is particularly preferable that the pit density is 1
× 10 ⁵ to 1 × 10 ⁷ pieces / mm ² . When the horizontal axis represents the hole diameter and the vertical axis represents the cumulative frequency (%), the hole diameter corresponding to 5% and 95% of the cumulative frequency curve is 0.7 μm or more.
It is preferably 20 μm or less, more preferably 0.8 μm or more and 15 μm or less. Also, 10% of the cumulative frequency curve, 90%
% Is preferably 0.9 μm or more and 10 μm or less. The arithmetic mean of the circle-converted pore diameter is 1.0 to
It is preferably 3 μm.

[Thin Layer] The photocatalytic metal oxide used in the present invention will be described. 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 in a printing plate manufacturing stage using titanium metal can also be used.

As the titanium oxide, any crystalline form can be used, but 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 that case, amorphous titanium oxide or rutile-type titanium oxide may coexist, but those containing 40% or more, preferably 60% or more of naatase-type crystals are preferable for the above reason.

R in RTiO ₃ is a metal atom belonging to the alkaline earth element of the periodic table, such as magnesium, calcium, strontium, barium and beryllium, and strontium and barium are particularly preferred. The above R is
Two or more kinds of alkaline earth metal atoms can coexist as long as their sum is stoichiometrically consistent with the above formula.

In the compound represented by the general formula AB _2-x C _x D _{3-x Ex} O ₁₀ , A is a monovalent atom selected from a hydrogen atom and an alkali metal atom such as sodium, potassium, rubidium, cesium and lithium. Two or more of the atoms may coexist as long as their sum matches the above formula stoichiometrically. B is an alkaline earth metal atom or a lead atom as defined above for R, and two or more kinds of atoms may coexist as long as they are stoichiometrically matched as described above. C is a rare earth atom, preferably scandium, yttrium, lanthanum, cerium, praseodymium, neodymium,
It is an atom belonging to a lanthanoid element such as holmium, europium, gadolinium, terbium, thulium, ytterbium, and lutetium. Is also good. D is one or more elements selected from Group 5A elements of the periodic table, and includes nitrogen, phosphorus, arsenic, antimony, and bismuth. As long as the stoichiometric relationship is satisfied,
Two or more group 5A elements may coexist. E is a metal atom belonging to Group 4 elements such as silicon, germanium, tin, lead, titanium, and zirconium, and two or more kinds of metal atoms of Group 4 may coexist. x represents an arbitrary numerical value of 0 to 2.

In the present invention, the above TiO_Two, RT
iO_Three, AB_2-xC_xD_3-xE_xO _Ten, SnO_Two, Zn
O, Bi_TwoO_ThreeAnd Fe_TwoO_ThreeAt least one of
Alternatively, a thin layer made of a combination of two or more
And provided on the surface of the printing original plate.

In order to provide the above-mentioned photocatalytic metal oxide used in the present invention on the surface of an original plate, for example, a method of applying a dispersion of the above-mentioned oxide fine particles on an original plate of a printing plate, a method of applying and then firing A method of reducing or removing the binder by, a method of forming a film of the above oxide on the original plate of the printing plate by various vacuum thin film methods, for example, after applying an organic compound such as an alcoholate of a metal element on the original plate, Any known method can be used, such as a method of performing hydrolysis and firing 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 containing the above-mentioned metal. In the present invention, a titanium oxide layer formed by vacuum deposition 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. Forming a surface layer by applying a mixed dispersion of titanium oxide and silicon oxide, titanium oxide and organopolysiloxane or a monomer thereof
And a method of applying a mixture thereof.

The above or the method of applying the barium titanate fine particles includes a method of applying a mixed dispersion of barium titanate and silicon to form a surface layer, and a method of applying barium titanate and an organopolysiloxane or a monomer thereof. And the like. Further, these metal oxides can be formed into a thin layer by dispersing and applying a polymer binder which can coexist with the oxide. As the binder for the oxide fine particles, a polymer having dispersibility in barium titanate fine particles can be widely used. Examples of preferred binder polymers include polyalkylene polymers such as polyethylene, polybutadiene, polyacrylate, polymethacrylate, polyvinyl acetate, polyvinyl formate, polyethylene terephthalate, polyethylene naphthalate, polyvinyl alcohol, partially saponified polyvinyl alcohol, Hydrophobic binders such as polystyrene are preferred, and these resins may be mixed and used. In the case of this method, in addition to titanium oxide and barium titanate, magnesium titanate, calcium titanate, strontium titanate, or an intermolecular compound or mixture thereof can be similarly formed into a thin film.

In the same manner, CsLa ₂
NbTi ₂ O ₁₀ fine particles can be applied. C
The sLa ₂ NbTi ₂ O ₁₀ fine particles are obtained by finely pulverizing Cs ₂ CO ₃ , La ₂ O ₃ , NbO ₅ , and TiO ₂ corresponding to the stoichiometry in a mortar and placing the mixture in a platinum crucible at 130 ° C. for 5 hours. After baking and cooling, it was put into a mortar and pulverized to fine particles of several microns or less. The CsLa ₂ NbTi ₂ O ₁₀ fine particles were dispersed in a binder in the same manner as the above-mentioned barium titanate, and coated to form a thin film. This method uses Cs
Not limited to La ₂ NbTi ₂ O ₁₀ type fine particles, HCa _{1.5
La 0.5 Nb 2. 5 Ti 0.5 O} 10, LaNbTi 2 O 10 such as previously described _{AB 2-x C x D 3} -x E x O 10, (0 ≦ x ≦ 2)
Applied to

As a method for forming the photocatalytic metal oxide layer using the above-described 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 binary oxide target is prepared in advance. For example, a barium titanate final 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. This method can form a thin film on the above-mentioned titanium oxide and RTiO ₃ (R is an alkaline earth metal atom) and other photocatalytic metal oxides by adjusting the substrate temperature which is optimal for controlling the crystal. It is possible. For example, when providing a tin oxide thin film,
By performing RF sputtering at a substrate temperature of 120 ° C. in an argon / oxygen mixed atmosphere, a barium titanate crystal thin film was obtained at a ratio of 50/50 and an RF power of 200 W
Thus, a thin film suitable for the purpose is obtained.

In order to perform vacuum deposition of titanium oxide,
Usually, metal titanium is placed as a heat source for heating for vapor deposition in a vacuum vapor deposition apparatus, and the total gas pressure is exp (−2 to −5) and the oxygen pressure ratio is 30 to 90% at a degree of vacuum exp (−− 5) Torr. Then, when the titanium metal is evaporated, a deposited thin film of titanium oxide is formed on the deposited surface.

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 electrolytic oxidation of the surface of a metal zinc plate and a method of forming a zinc oxide film by vacuum deposition are preferable. A method of 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 of 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.

The above-described method using a metal alcoholate is also a method capable of forming a target thin film without using a binder without using vapor deposition. To form a barium titanate thin film, a mixed alcohol solution of barium ethoxide and titanium butoxide is applied on a silicon substrate having SiO ₂ on its surface, and the surface is hydrolyzed.
It is possible to form a barium titanate thin film by heating to 00 ° C. or higher. This method uses the other RTiO
₃ (R is an alkaline earth metal atom), AB _2-x C _x D _3-x
E _x O ₁₀ (A, represents B, C, D, the contents of the definition of each of E above) can be applied to the thin film formation of the SnO _2, Bi ₂ O ₃ and Fe ₂ O _3.

Metal oxidation exhibiting the photocatalytic function described above
The method of forming a thin film is also based on a system that does not contain a binder.
It is possible to form a target thin film. SnO_TwoForm a thin film of
SnCl_FourHeat hydrochloric acid aqueous solution to over 200 ° C
Sprays on quartz or crystalline glass surfaces to form thin films
can do. This method uses SnO_TwoIn addition to thin film
RTiO mentioned_Three(R is an alkaline earth metal atom), AB
_2-xC_xD_3-xE_xO _Ten(A, B, C, D, E are each
Represents the content of the above definition), Bi_TwoO_ThreeAnd Fe_TwoO
_ThreeCan be applied to the formation of any of the thin films.

In any of the above cases, the thickness of the metal oxide thin film is preferably from 1 to 100,000 angstroms, and more preferably from 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 photocatalytic metal oxide when a binder is used, the volume ratio of the metal oxide is 50%.
It is preferable that the oxide occupy 90% or more, more preferably 90% or more, and more preferably a continuous layer of the oxide, that is, substantially 100%. In addition, it may be effective to dope a certain metal in order to enhance the property of changing the hydrophilicity of the surface by light irradiation. For this purpose, doping of a metal having a low ionization tendency is suitable. , Pd, Au, Ag, Cu, Ni, F
It is preferable to dope e and Co. Further, a plurality of these preferable metals may be doped.

[Image Forming Method] This thin layer has a property that its surface becomes hydrophilic by irradiation with actinic light. Utilizing this characteristic, imagewise exposure is performed using active light to generate an imagewise hydrophilic portion on the exposed surface, and then the surface is brought into contact with printing ink so that the image area accepts the ink. The printing surface is formed and printing is performed. After the printing, the ink remaining on the printing plate surface used is washed away, and then the original plate is uniformly heated to 80 ° C. or higher, and the exposed portion that has been rendered hydrophilic is obtained. The surface layer returns to its original hydrophobicity, and the entire surface becomes a uniform ink-receptive hydrophobic surface, so that the printing original plate is reproduced.
Therefore, it is a feature of the offset printing method that is the basis of the present invention that printing can be repeatedly performed using the printing master.

The phenomenon that the surface of the metal oxide is made hydrophilic by a photocatalytic reaction is described in JP-A-9-70541.
No. 9-77535, it is also possible to make the surface hydrophilic by actinic light and, at the same time, to make the surface hydrophobic by heating. The idea of applying it to a new type of offset printing is a new technical idea.

In the present invention, the image formation on the plate surface
Since various methods utilizing hydrophilicity by active light and hydrophobicity by heating (including heating by radiation converting light and heat) can be selected, a typical method will be described first. 1. After irradiating the thin layer on the surface of the original printing plate with the entire surface by activating light to make the entire thin layer hydrophilic, the thin layer surface is heated like an image, and the heated portion is changed to lipophilic so that the lipophilic portion is A method of forming a printing surface that accepts ink in the form of an image.
For example, a method is used in which a thermal print printer writes data directly from a print head by heat. Further, so-called light-heat converting radiation, in which absorbed light is converted into heat energy, in particular, infrared rays or laser beams may be irradiated in an image form. The active light may be modulated by an image, for example, laser light carrying electronic image information, or light irradiation through an image mask such as a negative film.

2. A method in which a hydrophobic thin layer on the surface of an original printing plate is irradiated imagewise with active light to change a portion to be irradiated to hydrophilicity, and a printing surface receiving lipophilic ink is formed on a portion not irradiated with light. In this method, the image-irradiated portion is the lipophilic portion and the ink-receiving portion, in that the image-irradiated portion is hydrophilic and is a portion that repels ink. Method and negative
A printing plate having a reverse positive relationship is obtained. In the above 1, the image-like irradiation light is light-heat conversion radiation, but in this case, the ultraviolet and visible regions are compared by making the thin layer surface photochemically excited to make it hydrophilic. For example, a light beam having a relatively short wavelength, a weak laser beam that does not cause light-heat conversion, or the like is used. The light beam itself may be image-modulated or may be irradiated through an image-like mask. As a preferred specific example of this method, a method of directly writing an electrophotographic image, an ink jet image, a thermal transfer image, a handwritten water-based pen image or an oil-based pen image on a thin layer surface, and printing it as a printing plate. Can be mentioned.
In this case, the written image may be lipophilic or hydrophilic, but in the case of hydrophilicity, the actinic light is used unless the image substance is easily dissolved in dampening water. After irradiation, the image portion is removed so that the ink is acceptable. This operation is not necessary if the image is lipophilic.

In any of the above 1 and 2, the method of the present invention has advantages of its simplicity and repetitive use of the original plate. It can be preferably used as a simple optical recording / offset printing means.

[Plate making] Various forms and materials can be used for the printing plate according to the present invention. For example, a method of directly providing an oxide layer by the above-described method such as vapor deposition, immersion or application of a photocatalytic metal oxide on the surface of a plate cylinder of a printing press, and providing a photocatalytic metal oxide layer on a surface of a metal plate. Can be used to form a printing plate by winding it around a plate cylinder.

A printing plate having a surface layer of a photocatalytic metal oxide is inherently lipophilic and accepts ink. However, when imagewise exposure is performed, a portion irradiated with light becomes hydrophilic.
Stop accepting ink.

The “change between lipophilicity and hydrophilicity by light irradiation” which is the basis of the present invention is extremely remarkable.
The greater the difference between the hydrophilicity and the lipophilicity of the image area and the non-image area, the more remarkable the discriminating effect, the sharper the printed surface, and the greater the printing durability. The difference between hydrophilicity and lipophilicity can be represented by a contact angle with a water droplet. The greater the hydrophilicity, the more the water droplet spreads and the smaller the contact angle becomes. On the contrary, if the water droplet repels (water repellency, ie, lipophilicity), the larger the contact angle becomes. In other words, the master having the photocatalytic metal oxide surface layer of the present invention originally has a high contact angle with water, but the contact angle sharply decreases when irradiated with actinic light, and the lipophilicity is reduced. The ink-repelling property changes to an ink-retaining portion and a water-retaining portion on the plate surface in an image-like manner, and the ink is transferred to the printing surface by coming into contact with an image receiving sheet such as paper.

The active light for exciting a thin layer mainly composed of a photocatalytic metal oxide has a photosensitive range of 400 nm or less, and emits a mercury lamp, a tungsten halogen lamp, other metal halide lamps, a xenon lamp, and other ultraviolet light. A discharge tube or the like can be used. As the excitation light, a helium cadmium laser having an oscillation wavelength of 325 nm or an oscillation wavelength of 351.1 to 363.8 n
Alternatively, a water-cooled argon laser having a value of m can be used. Further, in a gallium nitride laser system in which near-ultraviolet laser oscillation has been confirmed, the oscillation wavelength is 360 to 440 nm.
Based InGaN quantum well semiconductor laser and 360
A waveguide having an oscillation wavelength of ４430 nm, a MgO—LiNbO ₃ inversion domain wavelength conversion device type laser can also be applied.

According to the irradiation light amount, the photocatalytic metal
Oxide changes to hydrophilic by light absorption excitation
All photocatalytic metal oxides constituting the surface layer are activated
And further light irradiation change the degree of hydrophilicity further
I will not do it. The preferable irradiation light intensity is a photocatalytic metal mold.
Depends on the nature of the imaging layer
Although it depends on the wavelength and spectral distribution of light, it is usually used for printing
The surface exposure intensity before modulation with an image is 0.05 to 100 jo
ule / cm^Two, Preferably 0.05 to 10 joule
/ Cm^Two, More preferably 0.05 to 5 joule / c.
m ^TwoIt is. The amount of this irradiation is
Surface exposure method using a divergent light source
This is a level of light that does not cause any particular problem.

The above-described photosensitivity that causes a change from hydrophobic to hydrophilic by light is described in zirconia ceramics (JP-A-9-169098), which has been disclosed in both properties and mechanism.
Is different from the photosensitivity. For example, the sensitivity is described as a laser beam of 7 W / μm ² for zirconia ceramic, 70 joule / cm ^{2 when} the pulse duration of the laser beam is 100 nanoseconds, and the photocatalytic metal oxide layer Approximately one order of magnitude lower than sensitivity. Although the mechanism is not sufficiently elucidated, it is considered to be a photo-exfoliation reaction of the lipophilic organic deposit, and is different from the photo-change mechanism of zirconia.

After the image printing exposure is performed on the surface layer of the lipophilic photocatalytic metal oxide, the printing original plate can be directly sent to an offset printing step without development processing. Therefore, it has many advantages, mainly simplicity, as compared with the known lithographic printing method. That is, as described above, the chemical treatment with the alkaline developer is unnecessary, and the accompanying wiping and brushing operations are not required, and further, there is no environmental load due to the discharge of the waste developer.

The entire exposed area of the lithographic printing plate obtained as described above is sufficiently hydrophilic. If desired, washing water, a rinsing solution containing a surfactant, a gum arabic or a starch derivative may be used. It is post-treated with a desensitizing solution containing the same. As the post-processing when the image recording material of 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 application amount is made uniform by using 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 set on an offset printing machine or the like and used for printing a large number of sheets.

[Reproduction of Printing Plate] Next, the process of reproducing the printing plate after printing will be described. After printing, the printing plate is washed away with a hydrophobic petroleum-based solvent to remove attached ink. As the solvent, there are aromatic hydrocarbons such as kerosene and isoper as commercially available printing ink dissolving liquids,
Besides these, benzol, toluene, xylol, acetone, methyl ethyl ketone and a mixed solvent thereof may be used.

The printing plate from which the ink has been washed and removed is then subjected to a heat treatment, whereby the printing plate is uniformly made lipophilic over the entire plate surface, and the photosensitivity to uniform water-based recovery is restored.
The heat treatment is performed at 80 ° C. or higher, preferably at 100 ° C. or higher and at a firing temperature of titanium oxide or zinc oxide or lower,
The higher the temperature, the shorter the lipophilic time. More preferably 150 °
10 minutes or more at C or 1 minute or more at 200 ° C or 25
Heat treatment at 0 ° C. for about 10 seconds or more is preferable. There is no problem even if the heat treatment time is extended, but after the hydrophilicity of the surface is restored, even if the time is extended, no further advantage is produced.

As a heat source used for regeneration, any means can be used as long as it satisfies the above-mentioned conditions of temperature and time.
Examples of heating means include radiant heating by direct infrared irradiation, indirect infrared irradiation with a heat absorbing sheet such as black carbon paper contacting the printing plate surface, insertion into a temperature-controlled air bath, hot plate and other heat sources. Contact heating with the plate,
Examples include contact with a heating roller. The printing original plate thus recovered from the used printing plate is stored so as not to be exposed to actinic light, and is prepared for the next printing.

The reproducible number of times the printing original plate according to the present invention can be repeatedly reproduced is not completely understood, but is at least 15 times or more. It is considered that it is restricted by mechanical deformation (strain) of the plate material.

Experimental Example 1 In the electrolytic surface roughening treatment described in Example 1, a sample was prepared in which the applied voltage and the amount of anode electricity were controlled to change the average circular pore diameter. Using this sample, a test in which a thin layer of titanium oxide was provided by the method shown in Example 5 to perform the printing described in Example 5, and the used original plate was reproduced and printing was repeated. FIG. 4 is a diagram illustrating a relationship between a circle-converted radius, which is a measure of a rough surface, and a white background stain on a printing paper surface. On the vertical axis, the white background density of the second printing paper is set on the vertical axis with reference to the first printing paper.
The abscissa indicates the average pore diameter in circle of the sample. The white background density was determined by a reflection densitometer satisfying the geometric conditions of the measurement method of the reflection density specified in the international standards ISO5-2 and ISO5-4.

In FIG. 4, when the circle-converted average pore diameter is 0.5 μm or less, the reflection density on a white background is extremely high.
It is shown that the density of the white background is remarkably reduced from 0.9 μm to 0.9 μm.
It has been shown that a printing original plate having a photocatalytic metal oxide thin layer roughened to a micron or more has an effect of preventing an increase in the density of a white background due to residual ink due to reuse of the original plate.

[0086]

The present invention will be further described with reference to the following examples, but the present invention is not limited to these examples. Example 1 (Preparation of substrate) 0.01% by weight of copper, 0.03% by weight of titanium, and 0.3% of iron in 99.5% by weight aluminum
JIS A10 containing 0.1% by weight of silicon and 0.1% by weight of silicon
Rolled plate of 0.10mm thickness of 50 aluminum material
The surface was grained using a 20-mesh aqueous suspension of 0 mesh pumistone (manufactured by Kyoritsu Ceramics) 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 .
It was washed with running water. Further, the mixture was neutralized with 1% by weight of nitric acid, and then, in an aqueous solution of 0.7% by weight of nitric acid (containing 0.5% by weight of aluminum), the voltage at the time of anode was 10.5 volts and the voltage at the time of cathode was 9.
3 volt square wave alternating waveform voltage (current ratio r = 0.90,
Using the current waveform described in Examples of JP-B-58-5796), the quantity of electricity at the anode was set to 50, 100, 200.
And electrolytic surface roughening treatment was carried out in four ways of 400 clones / dm ² . After washing with water, it was immersed in a 10% by weight aqueous solution of sodium hydroxide at 35 ° C., etched so that the amount of aluminum dissolved was 1 g / m ² , and then washed with water. Next, it was immersed in a 30% by weight aqueous sulfuric acid solution at 50 ° C., desmutted, and washed with water.

Further, a porous anodic oxide film forming treatment was performed 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 of 0.30 measured with a Macbeth RD920 reflection densitometer, and the characteristics of the rough surface obtained by scanning with an atomic force microscope are as follows. there were.

[0089]

[Table 1]

Next, this aluminum substrate was sputtered.
5.0x10 ^-7Vacuum down to Torr
I care. The support is heated to 500 ° C., and Ar / O_TwoIs 6
The gas pressure was set to 5 × 10^-3To
rr. 6 inch φ barium titanate sintering machine
RF power 200W is applied to the target and the film pressure is 1000
A barium titanate thin film of Å was formed. X-ray analysis method
If so, this thin film was polycrystalline. Size 510x
The sample was cut into 400 mm. 4 on this surface
Lith film original with a positive image of 00 lines / inch
Was placed and mechanically contacted with a quartz glass plate from above. This
Light source device UNIREC for USIO baking made by USHIO Inc.
Using URM-600 format GH-60201X,
Degree 25mW / cm^TwoExposure was performed for 2 minutes under the following conditions.

The printing plate having the barium titanate thin film surface was set on a single-sided printing machine of Oliver 52 manufactured by Sakurai, the dampening water was purified water, and the ink was manufactured by Dainippon Ink and Chemicals, Inc.
500 sheets of offset printing were performed using Newchampion F gloss 85 ink. Clear prints were obtained from the start to the end, and no damage to the printing plate was observed.

Next, the surface of this plate was carefully washed with a printing ink washing liquid Daiclean R (sold by Dainippon Ink and Chemicals, Inc.) soaked in a waste to remove the ink. This was heated in an oven at 150 degrees for 10 minutes, and then cooled to room temperature, and the contact angle was measured in the same manner as before. At any point on the plate surface, the contact angle was in the range of 54 to 57 degrees, and the plate was restored to the initial state where no exposure was performed. In this state, exposure was further performed for 2 minutes at the same light intensity (25 mw / cm ² ) through the lith film having a positive image different from the first time, using the same light source as before (light source device for printing by Ushio Electric Co., Ltd.). As in the case of the first time, when the contact angle of the surface was measured by the aerial water drop method, an exposed portion of 7 degrees (measured at the irradiated portion also at the first time) and a non-exposed portion of 54 to 56 degrees were obtained.

This plate was set on a single-sided printing machine of Oliver 52 manufactured by Sakurai Co., Ltd., and pure water was used as dampening solution, and Newchampion F gloss 85 ink manufactured by Dainippon Ink and Chemicals, Inc. was used as ink.
00 sheet offset printing was performed. In the sample using the substrates 2 to 4, a clear printed matter is obtained from the start to the end,
No damage to the printing plate was observed. On the other hand, in the printing plate using the substrate 1, although within the allowable range, the degree of ink smearing increased from the initial stage of printing 500 sheets as compared with the first printing, and the reflection density of the white background portion became the first time. It was increased by 0.02 from the time of. The above repetition was performed 10 times. The reflection density of the white background portion of the tenth printed matter increased by 0.06 with respect to the substrate 1 and increased by 0.03 with respect to the substrate 2, but no stain on the substrates 3 and 4 was observed.

Example 2 In this example, a test was conducted by changing the type of the thin layer to tin oxide. The substrate 3 (Example of the present invention) and the substrate 1 (Comparative Example) of Example 1 were each set in a sputtering apparatus, and 5
Evacuation was performed to x10 ^-7 Torr. Support at 120 ° C
And the gas pressure of the argon / oxygen mixed gas (50/50 molar ratio) was adjusted to 5 × 10 ⁻³ Torr. RF power 1 on 6 inch φSnO ₂ sintered target
At a power of 50 W, a thin film of tin oxide having a film pressure of 1000 Å was formed. The size of this original plate is 510 × 40
The sample was cut to 0 mm.

A squirrel film manuscript having a positive image was placed on each surface, and was mechanically brought into close contact with a quartz glass plate from above. This was exposed to light for 10 minutes at a light intensity of 25 mW / cm ² using a USIO baking light source device UNIREC URM-600 model GH-60201X manufactured by USHIO Inc.

This plate was set on a single-sided printing machine of Oliver 52 manufactured by Sakurai Co., Ltd., and pure water was used as a dampening solution.
000 sheets of offset printing were performed. From the start to the end, a clear printed matter with no stain on the non-image portion was obtained, and no damage to the printing plate was observed. Next, a printing ink cleaning liquid DAICLEAN R in which the surface of the plate is impregnated with a waste cloth.
(Distributor: Dainippon Ink and Chemicals, Inc.) was carefully washed to remove the ink. This was heated in a 180 ° oven for 2 minutes to restore it to its initial state. In this state, exposure was performed for 10 minutes at the same light intensity (25 mw / cm ² ) through the lithographic film having a positive image different from the first time using the same light source as before (light source device for printing by Ushio Electric Co., Ltd.).

This plate was set on a single-sided printing machine of Oliver 52 manufactured by Sakurai Co., Ltd., and pure water was used as dampening water, and Newchampion F gloss 85 ink manufactured by Dainippon Ink and Chemicals, Inc. was used as ink.
000 sheets of offset printing were performed. Clear prints were obtained from the start to the end, and no damage to the printing plate was observed. When the above-described repetition was performed five times, the sample of the present invention using the substrate number 3 showed no change in the photosensitivity of the plate, the contact angle, and the speed of recovery of the contact angle due to heating. The whiteness was almost the same between the first to fifth times. On the other hand, the sample of the comparative example using the substrate number 1 was 2
An ink stain was observed on the printed surface of the second printing, and an increase of 0.06 in reflection density on a white background was observed. After the third time, a white background density 0.06 to 0.10 higher than that of the first time was observed. The results show that even when a printing plate having a tin oxide photosensitive layer provided on an aluminum support is used, a thin layer having a surface roughness within the range of the present invention reduces ink stains. Was.

Example 3 As in Example 2, the test of Example 2 was repeated using the aluminum substrates of substrate numbers 1 (comparative example) and 3 (invention) and changing the type of thin layer. That is, CsLa ₂
The surface was hydrolyzed by immersion in a 20% ethanol solution containing cesium ethoxide, titanium butoxide, lanthanum isobutoxide, and niobium ethoxide corresponding to the stoichiometric ratio of NbTi ₂ O ₁₀ and then heated to 200 ° C. or more. Thus, a thin film of CsLa ₂ NbTi ₂ O _{10 having} a thickness of 1000 Å was formed on the surface of the aluminum substrate.

The size of the anodized aluminum support with the composite metal oxide thin film was 510 × 400 mm.
Into a sample. A squirrel film manuscript having a positive image was placed on this surface, and mechanically adhered to the quartz glass plate from above. Ushio Electric Co., Ltd. USIO baking light source device UNIREC URM-600 type GH-60
Exposure was performed using 201X under a light intensity of 25 mW / cm ² for 5 minutes.

This plate was set on a single-sided printing machine of Oliver 52 manufactured by Sakurai Co., Ltd., and 500 sheets of offset printing were performed using pure water as dampening water and New Champion F gloss 85 ink manufactured by Dainippon Ink and Chemicals, Inc. as ink. Was. From the start to the end, a clear printed matter with no stain on the non-image portion was obtained, and no damage to the printing plate was observed. Next, a printing ink cleaning liquid DAICLEAN R in which the surface of the plate is impregnated with a waste cloth.
(Distributor: Dainippon Ink and Chemicals, Inc.) was carefully washed to remove the ink. 15 times in a 160 degree oven
It was heated for minutes to recover the initial state before exposure. In this state, exposure was performed for 5 minutes at the same light intensity (25 mw / cm ² ) using the same light source as before (a light source device for printing by Ushio Inc.) through a lith film having a positive image different from the first time.

This plate was set on a single-sided printing machine of Oliver 52 manufactured by Sakurai Co., Ltd.
000 sheets of offset printing were performed. Clear prints were obtained from the start to the end, and no damage to the printing plate was observed. In the sample of the present invention using the substrate 3, no change was observed in the photosensitivity of the plate, the contact angle, the contact angle recovery speed due to heating, and the like, and the whiteness of the white background of the printed surface was visually observed with the first printed surface. It was the same. On the other hand, in the sample of the comparative example using the substrate 1, ink stain was observed on the second printed surface. Regarding the reflection density of the white background, the sample of the present invention using the substrate 3 is the same as the reflection density of the first printed surface, and the sample of the comparative example using the substrate 1 has an increase of 0.08. Was.
From this result, it was found that CsLa ₂ Nb
It was shown that even when a printing original plate in which a thin film of Ti ₂ O _{10 having} a thickness of 1000 angstroms was provided by firing was used, the thin layer having the above-mentioned level of roughness on the surface reduced ink stains.

Example 4 Using the aluminum substrates of substrate Nos. 1 (comparative example) and 3 (invention) shown in Example 1, a sample having a thin layer of barium titanate provided thereon was used. In the same manner as in Example 1, plate making, printing, reproduction of a plate material, and second printing were performed. That is, the aluminum substrates of substrate numbers 1 and 3 are set in a sputtering apparatus and evacuated to 5.0 × 10 ⁻⁷ Torr. The substrate was heated to 150 ° C. and the gas pressure was adjusted to 5 × 10 ⁻³ so that Ar / O ₂ became 30/70 (molar ratio).
Adjusted to Torr. RF power of 200 W was applied to a 6-inch φ barium titanate sintered target to achieve a film pressure of 100 mm.
A 0 ° barium titanate thin film was formed. Size 51
The sample was cut into 0 × 400 mm.

A light source device for the USIO baking, Uileo URM-60, manufactured by Ushio Electric Co., Ltd.
The whole surface was exposed for 2 minutes under a light intensity of 9 mW / cm ² using a GH-60201X 0 format. 830 nm
A semiconductor laser beam having a beam width of 45 microns (1 / e ²
Value), and image-exposed under the following conditions. Scanning speed: 1.9 m / sec scanning pitch: 22.5 microns energy density: 785 mJ / cm ²

The plate thus drawn with the semiconductor laser light in the infrared region was set on a single-sided printing machine of Oliver 52 manufactured by Sakurai, the dampening water was purified water, and the ink was New Champion F gloss manufactured by Dainippon Ink and Chemicals, Inc. 1000 using 85 ink
Offset printing was performed. The laser-exposed portion became an ink receiving portion, and from the start to the end, a clear printed matter was obtained without stain on the non-image portion, and no damage to the printing plate was observed.

Next, the surface of the plate after printing was thoroughly washed with a printing ink cleaning liquid DAICLEAN R (sold by Dainippon Ink and Chemicals, Inc.) soaked in a waste to remove the ink. Under the same conditions as in Example 1, the light source device for USIO baking manufactured by USHIO Inc. UNIREC URM-600
Using Model GH-60201X, the entire surface was exposed under a light intensity of 9 mW / cm ² for 2 minutes. Next, the surface of this sample was exposed to a laser image using the semiconductor laser of Example 1 under the same conditions, except for a drawn image.

This plate was set on a single-sided printing machine of Oliver 52 manufactured by Sakurai Co., Ltd., and the dampening solution was pure water, and the ink was Newchampion F gloss 85 ink manufactured by Dainippon Ink and Chemicals, Inc.
00 sheet offset printing was performed. In the sample of the present invention using the substrate 3, a clear printed matter having the same white background reflection density was obtained from the start to the end, and no damage to the printing plate was observed. On the other hand, in the printing plate using the substrate 1, although within the allowable range, the degree of dirt on the white background has increased from the initial stage of printing 500 sheets as compared with the first printing, and the reflection density of the white background is lower than the optical reflection density. The concentration increased by 0.09.

Example 5 Using the aluminum substrates (thickness: 100 μm) of substrate numbers 1 (comparative example) and 3 (invention) shown in Example 1, a thin layer of titanium oxide was provided thereon. Plate making, printing, plate material regeneration, and second printing were performed in the same manner as in Example 1 using the sample. Each of the aluminum substrates of substrate numbers 1 and 3 was heated in a vacuum deposition apparatus at a total pressure of 1.5 × 10 ⁻⁴ Torr and a partial pressure of oxygen gas of 70% to form a titanium oxide thin film by vapor deposition. The crystal component of this thin film has an amorphous / anatase / rutile crystal structure ratio of 1.5 / 6.5 / 2 by X-ray analysis, and the thickness of the TiO ₂ thin film is 900
Angstrom. Size is 510 x 400mm
Into a sample. These two types of original plates were each set in an electrophotographic apparatus instead of recording paper, and a toner image was formed by an electrostatic recording method. Ushio Electric Co., Ltd. USIO baking light source device UNIREC UR
Light intensity 9 using M-600 format GH-60201X
Exposure was performed for 2 minutes under mW / cm ² .

This plate was set on a single-sided printing machine of Oliver 52 manufactured by Sakurai Co., Ltd.
00 sheet offset printing was performed. Clear prints were obtained from the start to the end, and no damage to the printing plate was observed.

When the surface of the printing plate used for the above printing is immersed in a 1/1 mixed solvent of printing ink cleaning liquid Daiclean R (released by Dainippon Ink Industries, Ltd.) and toluene, about 1
In 5 seconds, the image and ink dissolved and flowed off. After the ink was carefully washed to remove the ink, it was heated in a 150 ° C. oven for 10 minutes to recover the initial state before exposure. In this state, the toner image was set on the same electrophotographic apparatus as the first time, and a toner image different from the first time was transferred and formed by the electrostatic recording method. Next, using the same light source as before the original sample (lighting device for baking manufactured by Ushio Electric Co., Ltd.), the same light intensity (9 mw / c
The exposed for 2 minutes was performed in m ^2.

This plate was set on a single-sided printing machine of Oliver 52 manufactured by Sakurai Co., Ltd., and pure water was used as dampening solution, and Newchampion F gloss 85 ink manufactured by Dainippon Ink and Chemicals, Inc. was used as ink.
00 sheet offset printing was performed. In the sample of the present invention using the substrate 3, a clear printed matter having the same white background reflection density was obtained from the start to the end, and no damage to the printing plate was observed. On the other hand, in the printing plate using the substrate 1, although within the allowable range, the degree of dirt on the white background has increased from the initial stage of printing 500 sheets as compared with the first printing, and the reflection density of the white background is lower than the optical reflection density. The concentration increased by 0.08.

Example 6 A printing plate of the following thermal printing system was prepared using a sample in which a thin layer of barium titanate was provided on the substrate Nos. 1 and 3 of Example 1. The size was cut into 510 x 400 mm to make a sample.

Using a thermal printer in which 150 μm × 150 μm thermal heads provided with a sialon abrasion protection layer on a Ta—SiO ₂ heating resistor are arranged at 250 μm intervals,
Temperature-increasing printing was performed by contacting with a barium titanate surface layer. The temperature of the used thermal head reached 450 ° C. by applying a current of 20 msec, and it was confirmed by separately performing temperature measurement. The recording speed was 400 msec / m. The hot-melt ink used is a commercially available ink having a melting point of 62 ° C. comprising 20% by weight of pigment, 20% by weight of carnauba wax, 40% by weight of ester wax, 10% by weight of linseed oil, and 10% of binder resin. Was used.

A USIO baking light source device UNIREC URM-600 type GH-60201X manufactured by USHIO Inc.
Exposure was performed at a light intensity of 9 mW / cm ² for 2 minutes.

This plate was set on a single-sided printing machine of Oliver 52 manufactured by Sakurai Co., Ltd.
00 sheet offset printing was performed. Clear prints were obtained from the start to the end, and no damage to the printing plate was observed.

The surface of the used plate was soaked with a 1/1 mixed solution of printing ink cleaning liquid Daiclean R (released by Dainippon Ink and Chemicals, Inc.) and toluene into a waste cloth and carefully washed to remove the ink and the image material. Was removed. This was heated in a 150 degree oven for 10 minutes. In this state, an image different from the first image was subjected to thermal transfer printing, and exposure was performed for 2 minutes at the same light intensity (9 mw / cm ² ) using the same light source as before (lighting device for printing made by Ushio Electric Co., Ltd.).

This plate was set on a single-sided printing machine of Oliver 52 manufactured by Sakurai Co., Ltd., and the dampening solution was pure water, and the ink was 30% as Newchampion F gloss 85 ink manufactured by Dainippon Ink and Chemicals, Inc.
Zero offset printing was performed. In the sample of the present invention using the substrate 3, a clear printed matter having the same white background reflection density was obtained from the start to the end, and no damage to the printing plate was observed. On the other hand, in the printing plate using the substrate 1, although within the allowable range, the degree of stain on the white background has increased from the initial stage of printing 500 sheets as compared with the first printing, and the reflection density of the white background has an optical reflection density. The concentration increased by 0.06.

Example 7 The size of the substrate 1 (comparative example) and the substrate 3 (example of the present invention) used in Example 5 in which a thin layer of titanium oxide was provided on the aluminum substrate was 510.times.400 mm. The following experiment was performed after cutting. 20% by weight of a copper phthalocyanine-based inorganic pigment as a colorant, 30% by weight of linseed oil as a vehicle, 38% by weight of toluene as a solvent on the surface of the sample,
An illustration pattern was drawn using an oil-based ink composed of 10% by weight of polyethylene wax and 2% by weight of a manganese dryer. Ushio Electric Co., Ltd. USIO baking light source device UNIREC URM-600 type GH-6
Exposure was performed using 0201X under a light intensity of 9 mW / cm ² for 2 minutes.

This plate was set on a single-sided printing machine of Oliver 52 manufactured by Sakurai Co., Ltd.
00 sheet offset printing was performed. From the start to the end, a clear printed matter with no stain on the non-image portion was obtained, and no damage to the printing plate was observed.

The surface of the used plate was impregnated with a 1/1 mixed solution of printing ink cleaning liquid Daiclean R (released by Dainippon Ink and Chemicals, Inc.) and toluene into a waste cloth and carefully washed to remove the ink. . This was heated in an oven at 180 degrees for 2 minutes to recover the initial state before exposure. In this state, an illustration image different from the first one was drawn, and exposure was performed for 2 minutes at the same light intensity (9 mw / cm ² ) using the same light source as before (a light source device for printing by Ushio Electric Co., Ltd.).

This plate was set on a single-sided printing press of Oliver 52 manufactured by Sakurai Co., Ltd., and the dampening solution was pure water, and the ink was Newchampion F Gloss 85 ink manufactured by Dainippon Ink and Chemicals, Inc.
00 sheet offset printing was performed. In the sample of the present invention using the substrate 3, a clear printed matter having the same white background reflection density was obtained from the start to the end, and no damage to the printing plate was observed. On the other hand, in the printing plate using the substrate 1, although within the allowable range, the degree of stain on the white background has increased from the initial stage of printing 500 sheets as compared with the first printing, and the reflection density of the white background has an optical reflection density. The concentration increased by 0.06.

Example 8 An aluminum substrate 3 having a thickness of 100 μm was set in a vacuum evaporation apparatus, and zinc selenide was evaporated to a thickness of 1000 Å under a vacuum of a total pressure of 5 × 10 ⁻³ Torr.
This was oxidized in air at 600 ° C. for 2 hours to form a thin film of zinc oxide on one surface of the substrate.

This 100-micron substrate with a zinc oxide film was cut into a size of 510 × 400 mm to obtain a sample. This sheet was mounted on an ink jet printer, and an oil-based ink image was recorded on the surface. The oil-based ink was 50 g of a latex dispersion obtained by dispersing 10 parts by weight of a vinyl acetate / methacrylic acid ester-based copolymer resin in 30 parts by weight of Isopar H, dodecyl methacrylate / acrylic acid (95 /
5 weight ratio) An oil-based ink prepared by diluting 10 g of copolymer, 10 g of alkali blue, 30 g of Shellsol 71, 30 g of dispersion, 10 g of tetradecyl alcohol, and 0.16 g of octacene / octadecyl alcohol maleate copolymer in 1 liter of Isopar G was used. Was. USU made by USHIO Inc.
Light source device for IO printing, Unirec URM-600 type G
Using H-60201X, light intensity of 9 mW / cm ² and 2
Exposure was performed for 0 minutes.

This plate was set on a single-sided printing press of Oliver 52 manufactured by Sakurai Co., and the dampening solution was pure water, and the ink was New Champion F gloss 85 ink manufactured by Dainippon Ink and Chemicals, Inc.
00 sheet offset printing was performed. From the start to the end, a clear printed matter with no stain on the non-image portion was obtained, and no damage to the printing plate was observed.

The surface of this plate was thoroughly washed with a 1/1 mixed solution of a printing ink washing liquid, Daiclean R (released by Dainippon Ink and Chemicals, Inc.) and toluene, and the ink was carefully removed to remove the ink. One in a 160 degree oven
Heating was performed for 5 minutes to recover the state before using as a printing plate. In this state, an image different from the first time was recorded on the printing plate using the above-described ink jet printer and oil-based ink, and then the same light source (USIO Electric Co., Ltd. USIO baking light source device UNIREC URM-600 format GH-60) was used.
201X) at the same intensity (9 mW / cm ² ) for 2 minutes.

This plate was set on a single-sided printing machine of Oliver 52 manufactured by Sakurai Co., Ltd., and the dampening solution was pure water, and the ink was Newchampion F gloss 85 ink manufactured by Dainippon Ink and Chemicals, Inc.
00 sheet offset printing was performed. A clear printed matter was obtained from the start to the end, and no increase in white background density and no damage to the printing plate were observed.

Example 9 The size of the substrate 1 (comparative example) and the substrate 3 (example of the present invention) used in Example 5 in which a thin layer of titanium oxide was provided on an aluminum substrate was set to 510 × 400 mm. The following experiment was performed after cutting. The substrate was heated in a vacuum deposition apparatus at a total pressure of 1.5 × 10 ⁻⁴ Torr and a partial pressure of oxygen gas of 70% to form a titanium dioxide thin film by vapor deposition. The crystal component of this thin film is amorphous /
The ratio of anatase / rutile crystal structure is 1.5 / 6.5 / 2
And the thickness of the TiO ₂ thin film was 900 Å. The size was cut into 510 x 400 mm to make a sample. The original plate was mounted on an ink jet printer (Epson PM-700C) instead of recording paper to form a water-based ink image. The composition of this aqueous ink was 7% by weight of glycerin, 8% by weight of diethylene glycol, 7% by weight of butyl ether, 1.5% by weight of CI Direct Green 1 (water-soluble dye), and 28% by weight of CI Direct Green 28
(Water-soluble dye) 1.5% by weight and 75% by weight of water. The polyethylene terephthalate (PET) film with the image was exposed for 2 minutes at a light intensity of 9 mW / cm ² using a USIO baking light source device UNIREC URM-600 type GH-60201X manufactured by USHIO Inc. Next, the film was lightly washed with running water to remove the image.

This plate was set on a single-sided printing machine of Oliver 52 manufactured by Sakurai Co., Ltd., and the dampening solution was pure water, and the ink was 50% as Newchampion F gloss 85 ink manufactured by Dainippon Ink and Chemicals, Inc.
Zero offset printing was performed. Clear prints were obtained from the start to the end, and no damage to the printing plate was observed.

Next, when the surface of this plate was immersed in a 1/1 mixed solvent of toluene and Dainippon Ink Kogyo Co., Ltd., the ink flowed off in about 15 seconds. After washing to remove the ink,
This was heated in an oven at 150 ° C. for 10 minutes to restore it to its initial state before use as a printing plate. In this state, the same ink-jet printer as the first time was loaded to form an ink image different from the first time. After using the same light source as before (lighting device for baking manufactured by Ushio Electric Co., Ltd.), this plate was exposed for 2 minutes at the same light intensity (9 mw / cm ² ).
The image was washed away with running water.

This plate was set on a single-sided printing machine of Oliver 52 manufactured by Sakurai Co., Ltd., and the dampening solution was pure water, and the ink was 50% as Newchampion F gloss 85 ink manufactured by Dainippon Ink and Chemicals, Inc.
Zero offset printing was performed. In the sample of the present invention using the substrate 3, a clear printed matter having the same white background reflection density was obtained from the start to the end, and no damage to the printing plate was observed. On the other hand, in the printing plate using the substrate 1, although within the allowable range, the degree of stain on the white background has increased from the initial stage of printing 500 sheets as compared with the first printing, and the reflection density of the white background has an optical reflection density. The concentration increased by 0.06.

Example 10 The size of the substrate 1 (comparative example) and the substrate 3 (example of the present invention) used in Example 5 in which a thin layer of titanium oxide was provided on an aluminum substrate was reduced to 510 × 400 mm. The following experiment was performed after cutting. A 400-line / inch positive image was printed and the tanning developed matrix film was pressed against the original in a wet state to transfer a silver salt / gelatin image. Ushio Electric Co., Ltd. USIO baking light source device UNIREC URM-600 type GH-6020
Exposure was performed for 2 minutes using 1X under a light intensity of 9 mW / cm ² , and then the image was lightly squeezed with a wet sponge to remove the image.

This plate was set on a single-sided printing machine of Oliver 52 manufactured by Sakurai Co., Ltd., and the dampening solution was pure water, and the ink was 50% as Newchampion F gloss 85 ink manufactured by Dainippon Ink and Chemicals, Inc.
Zero offset printing was performed. Clear prints were obtained from the start to the end, and no damage to the printing plate was observed.

Then, the surface of this plate was carefully washed with a printing ink washing liquid Dieclean R (a sales agency; Dainippon Ink and Chemicals, Inc.) soaked in a waste to remove the ink. This was heated in an oven at 150 ° C. for 10 minutes to recover the state before use as a printing plate. In this state, image transfer was further performed from a matrix film having an image different from the first image. Using the same light source as before (lighting device for baking manufactured by USHIO Inc.), the same light intensity (9 mw / cm ²
For 2 minutes.

This plate was set on a single-sided printing machine of Oliver 52 manufactured by Sakurai Co., Ltd., and the dampening solution was pure water, and the ink was 50% as Newchampion F gloss 85 ink manufactured by Dainippon Ink and Chemicals, Inc.
Zero offset printing was performed. In the sample of the present invention using the substrate 3, a clear printed matter having the same white background reflection density was obtained from the start to the end, and no damage to the printing plate was observed. On the other hand, in the printing plate using the substrate 1, although within the allowable range, the degree of dirt on the white background has increased from the initial stage of printing 500 sheets as compared with the first printing, and the reflection density of the white background is lower than the optical reflection density. The concentration increased by 0.09.

Example 11 The size of the substrate 1 (comparative example) and the substrate 3 (example of the present invention) used in Example 5 in which a thin layer of titanium oxide was provided on an aluminum substrate was set to 510 × 400 mm. The following experiment was performed after cutting.

This support with a thin layer of titanium oxide was replaced with an ink jet printer (Epson PM-
700C) to form an aqueous ink image. The composition of this aqueous ink is 20% by weight of N-methylpyrrolidone, 20% by weight of diethylene glycol, 5% by weight of polyethylene glycol (molecular weight 300), 5% by weight of CI Direct Black 19 (water-soluble dye), and 50% by weight of water. USIO made by Ushio Electric Co., Ltd.
Light source device for printing Unirec URM-600 type GH
Using -60201X, exposure was performed under a light intensity of 9 mW / cm ² for 2 minutes.

This plate was set on a single-sided printing machine of Oliver 52 manufactured by Sakurai Co., Ltd., and the dampening water was pure water, and the ink was 50% as Newchampion F gloss 85 ink manufactured by Dainippon Ink and Chemicals, Inc.
Zero offset printing was performed. Clear prints were obtained from the start to the end, and no damage to the printing plate was observed.

Next, when the surface of this plate was immersed in a toluene / cleanser (1/1) mixed solvent, the ink and the image flowed off in about 15 seconds. However, it seems that the image substance had already been absorbed into the ink before the solvent immersion. After carefully cleaning to remove the ink, this is heated to 150 °
The mixture was heated in a bun for 10 minutes to recover the state before use as a printing plate. In this state, the same ink-jet printer as the first time was loaded to form an ink image different from the first time. Next, the original plate with the image was exposed for 2 minutes at the same light intensity (9 mw / cm ² ) using the same light source as before (a light source device for printing by Ushio Inc.).

This plate was set on a single-sided printing machine of Oliver 52 manufactured by Sakurai Co., Ltd., and the dampening solution was pure water, and the ink was 50% as Newchampion F gloss 85 ink manufactured by Dainippon Ink and Chemicals, Inc.
Zero offset printing was performed. In the sample of the present invention using the substrate 3, a clear printed matter having the same white background reflection density was obtained from the start to the end, and no damage to the printing plate was observed. On the other hand, in the printing plate using the substrate 1, although within the allowable range, the degree of dirt on the white background has increased from the initial stage of printing 500 sheets as compared with the first printing, and the reflection density of the white background is lower than the optical reflection density. The concentration increased by 0.09.

[0139]

According to the present invention, there is provided a printing plate according to the present invention having a thin layer containing the above-mentioned photocatalytic metal oxide as a main component and having a surface roughness of the thin layer of at least 1 micron in terms of circle. The printing screen is formed only by imagewise exposure with actinic light, no developer is required, and offset printing can be performed while maintaining the clearness of the printing surface. Even when used, there is little ink stain and the quality of the printing paper surface can be maintained.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of a mechanical surface roughening process using a brush.

FIG. 2 is a schematic view showing an example of a chemical etching process of an aluminum surface.

FIG. 3 is a schematic view showing an example of a step of performing first and second electrolytic surface roughening treatments on an aluminum support.

FIG. 4 is an experimental example showing the relationship between the degree of the rough surface of the support and the white background stain on the printing paper surface.

[Explanation of symbols]

 Reference Signs List 101 Worked plate 102 Brush roll 103 Polishing slurry 107 Support roller 201 Nip roll 202 Pass roll 204 Feed pump 205 Liquid preparation tank 207 Precipitation tank 212 Supply pipe 222 Aluminum plate 301 Aluminum support 302 Surface roughening device 304 Backside rough surface Treatment device 305 Electrolyzer 306 Main electrode

Continuing on the front page (72) Inventor Nobufumi Mori 798, Miyadai, Kaisei-cho, Ashigara-gun, Kanagawa Prefecture Photo Film Co., Ltd. F-term (reference) 2H096 AA06 CA03 JA04 LA13 2H114 AA04 AA22 AA23 AA24 BA02 BA05 DA05 DA08 EA04 GA27 GA29 GA38

Claims (7)

[Claims] 1. 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 belonging to the same group 4 element. Atom, x represents any numerical value from 0 to 2),
An original printing plate having a thin layer made of at least one of SnO ₂ , Bi ₂ O ₃ and Fe ₂ O ₃ , wherein the surface of the thin layer has a concave portion having a circular arithmetic mean pore diameter of at least 1.0 μm. Plate for offset printing, characterized by having a rough surface composed of 2. The method according to claim 1, wherein the degree of hydrophilicity and lipophilicity of the thin layer provided on the substrate surface is changed imagewise by irradiation with actinic light and heat treatment, and then the thin layer is brought into contact with a printing ink to obtain lipophilicity. A part of a printing plate for forming a printing surface that has received the ink, and after the ink remaining on the printing plate surface after washing is removed by washing, the surface of the printing plate is heated to 80 ° C. or higher to thereby remove the printing plate. The original plate for offset printing according to claim 1, wherein the original plate can be returned to a state before use and used repeatedly. 3. The printing original plate according to claim 1 or 2, which is irradiated with actinic light and heat-treated to change the degree of hydrophilicity and lipophilicity of the thin layer on the surface of the printing plate in an image-like manner. The thin layer is brought into contact with the printing ink to form a printing surface in which the lipophilic portion has received the ink, and printing is performed. After the printing is completed, the ink remaining on the printing plate surface is washed and removed. An offset printing method characterized by repeatedly using the printing original plate by heating the original plate to a state before use by heating the original plate to a temperature before use. 4. A step of: 1) irradiating the entire surface of a printing original plate with a thin layer of active light to make the entire surface of the thin layer hydrophilic, and 2) heating the surface of the thin layer image-wise to reduce the heated portion. 3) a step of bringing the thin layer surface into contact with a printing ink to form a printing surface in which the lipophilic portion has received the ink and performing offset printing; The above-mentioned printing original plate is repeatedly used by sequentially performing a step of washing and removing the ink remaining on the layer surface and a step of heating the thin layer surface to 80 ° C. or more to return the entire thin layer to a lipophilic state. The offset printing method according to claim 3, wherein 5. A step of: 1) irradiating a thin layer on the surface of an original printing plate with an active light to make the entire thin layer hydrophilic, 2) applying light / heat converting radiation to the thin layer surface in an imagewise manner. Irradiate
Changing the irradiated portion to lipophilic; 3) contacting the thin layer surface with a printing ink to form a printing surface in which the lipophilic portion has received the ink to perform offset printing; After the completion, the printing is performed by sequentially performing a step of washing and removing the ink remaining on the thin layer surface and a step of heating the thin layer surface to 80 ° C. or more to return the entire thin layer to a lipophilic state. 5. The offset printing method according to claim 3, wherein the original plate is used repeatedly. 6. A step of 1) performing imagewise irradiation with actinic light on a thin layer on the surface of a printing original plate to change a portion to be irradiated to hydrophilicity, 2) bringing the thin layer surface into contact with a printing ink, A step of performing offset printing by forming a printing surface in which the oily portion has received the ink; 3) a step of washing and removing the ink remaining on the thin layer surface after the printing is completed;
4. The offset printing method according to claim 3, wherein the original printing plate is repeatedly used by sequentially performing a step of heating the entire thin layer to a lipophilic state by heating to 0 ° C or more. 7. The offset printing method according to claim 3, wherein the active light used for the imagewise irradiation is a laser beam.