JP5902981B2 - Planographic printing plate making method - Google Patents

Description

  The present invention relates to a plate making method of a lithographic printing plate using a silver complex diffusion transfer method.

  For lithographic printing plates using the silver complex diffusion transfer method (DTR method), published by Focal Press, London New York (1972), by Andre Lot and Edith Weide, "Photographic Silver Halide Diffusion Processes", Some examples are described on pages 101-130.

  A lithographic printing plate using a silver complex diffusion transfer method (DTR method) (hereinafter also referred to as a DTR lithographic printing plate), particularly a lithographic printing plate having a physical development nucleus layer on a silver halide emulsion layer is disclosed in, for example, US Pat. No. 4,728,114, No. 4,134,769, No. 4,160,670, No. 4,336,321, No. 4,501,811. No. 4,510,228, No. 4,621,041 and the like.

  In these DTR lithographic printing plates, the exposed silver halide crystals undergo chemical development in the emulsion layer by the development process to become blackened silver, thereby forming a hydrophilic non-image area. On the other hand, unexposed silver halide crystals are solubilized by a silver complex salt-forming agent in the developer, then diffused to the physical development nucleus layer on the surface, and further so-called dissolution physical development by the reducing action of the developing agent on the physical development nucleus. And is deposited as ink-receptive image silver. Therefore, the DTR lithographic printing plate has a mechanism in which chemical development and dissolution physical development proceed simultaneously during a single development process. In order to obtain a good printed material in lithographic printing, chemical development that becomes a non-image area is performed. A clear difference and contrast between the generated area and the area where the dissolved physical development that becomes the image portion is generated become important.

  The plate making method of the DTR lithographic printing plate is such that the exposed DTR lithographic printing plate is passed through a developing tank in which a large amount of developer is stored, and the developer remaining on the plate surface of the printing plate after passing is passed between rollers. In order to further squeeze out and further adjust the pH of the plate surface, a method of passing through a neutralizing solution (stabilizing solution) tank and removing the neutralizing solution remaining on the plate surface in the same manner as the developing solution, so-called immersion development method is generally known. ing. JP-A-48-76603, JP-A-57-115549, US Pat. No. 5,398,092 and the like describe coating development in which a developer is applied and supplied to the plate surface of a lithographic printing plate. A scheme is disclosed.

  Conventionally, the plate making of a DTR lithographic printing plate is generally performed by photographing a document with a camera. However, in recent years, with the advancement of computers and peripheral technologies, a computer that scans digital information of a computer directly with a laser light source is used. A plate making method called -to-plate (CTP) is becoming mainstream. This makes it easy to improve the image quality of a DTR lithographic printing plate and enables rapid plate-making work. However, the CTR plate making speed of the DTR lithographic printing plate and the offset printing time using the lithographic printing plate are large. As a result of the divergence, there is a relatively increasing number of cases where offset printing is performed over several days after making a large amount of lithographic printing plate at a time.

  However, the DTR lithographic printing plate may not be able to remove ink stains once attached to the non-image area after several days have passed since the plate making (hereinafter referred to as ink detachment failure), and improvement has been desired. When printing using a lithographic printing plate that causes ink detachment failure, if the printer is temporarily stopped during printing, ink stains will occur during reprinting, making it impossible to continue printing. Several lithographic printing plates were prepared to complete.

JP-A-10-282675 JP 2009-244452 A

  An object of the present invention is to provide a plate making method for a lithographic printing plate which does not cause ink detachment failure and does not cause printing failure even if it is a lithographic printing plate left for several days after plate making.

The above object of the present invention has been achieved by the following plate making method of a lithographic printing plate.
1. A lithographic printing plate having at least a silver halide emulsion layer and a physical development nucleus layer in this order on a support, a piperazine compound or aminoalkyl having an alkanolamine compound content of 30 mmol / L or less and having an aminoalkyl group Developed with a developer containing a morpholine compound having a thioether compound and a piperazine compound having an aminoalkyl group or a morpholine compound having an aminoalkyl group that is 2 to 8 times (molar ratio) of the thioether compound A process for making a lithographic printing plate to be processed .

  According to the present invention, it is possible to provide a plate making method of a lithographic printing plate that does not cause ink detachment failure and does not cause printing failure even if it is a lithographic printing plate left for several days after plate making.

Hereinafter, the developer used in the present invention will be described in detail.
In a developer used for making a lithographic printing plate using the silver complex diffusion transfer method, a method using an alkanolamine as a silver halide solvent has been widely used and indispensable. Preferably, N- (2-aminoethyl) ethanolamine is often used, but in order to achieve the object of the present invention, the content of the alkanolamine compound in the developer is preferably 30 mmol or less per liter, more preferably Needs to be 0 mmol.

  In the present invention, as the piperazine compound having an aminoalkyl group or the morpholine compound having an aminoalkyl group contained in the developer, compounds represented by the following general formulas 1 to 3 can be preferably used.

In the formula, L ₁ , L ₂ , L ₃ and L ₄ represent an alkylene group, and R ₁ , R ₂ , R ₃ and R ₄ each represent a linear or branched alkyl group, an aryl group or a hydrogen atom. Examples of the alkylene group of L _{1 to} L ₄ include an ethylene group, a propylene group, and a butylene group, and an ethylene group is preferable. R _{1 to} R ₄ are preferably hydrogen atoms. Specific examples of these compounds are shown below, but the present invention is not limited thereto.

  In the present invention, the piperazine compound having an aminoalkyl group or the morpholine compound having an aminoalkyl group is preferably contained in an amount of 40 to 800 mmol per liter of the developer.

  As the thioether compound contained in the developer in the present invention, for example, compounds described in JP-A-10-282684 can be used, but 3,6-dithia-1,8-octanediol, 2,2′- It is preferable to use thiodiethanol. These compounds are preferably contained in an amount of 1 to 300 mmol, and more preferably 5 to 200 mmol, per liter of the developer.

  There is a preferable range in the ratio of the content of the piperazine compound having an aminoalkyl group or the morpholine compound having an aminoalkyl group and the content of the thioether compound, and the piperazine compound having an aminoalkyl group or the aminoalkyl group has an aminoalkyl group. The content of the morpholine compound is preferably 2 to 8 times (molar ratio) of the thioether compound. This makes it possible to obtain a plate making method that is particularly excellent in ink detachability.

  The pH of the developer used in the present invention is preferably 11.0 to 14.0, more preferably 12.5 to 14.0. As the pH adjuster, an alkaline substance such as potassium hydroxide or sodium hydroxide can be used.

  As other components that can be contained in the developer, it is preferable to contain, for example, sulfite as a preservative. Specific examples of the sulfite include sodium sulfite, potassium sulfite, sodium bisulfite, potassium bisulfite and the like. Furthermore, thiosulfate, thiosalicylic acid, mesoionic compounds, cyclic imide compounds and the like can be contained.

  Further, the developer used in the present invention preferably contains a compound having a mercapto group or a thione group as a lipophilic agent in order to improve the ink acceptability of the silver image portion. Examples of such compounds include compounds described in JP-B-48-29723, JP-A-58-127928 and the like. A nitrogen-containing heterocyclic compound having a lipophilic group such as an alkyl group having 3 to 12 carbon atoms, an aryl group, or an alkenyl group is particularly preferable.

  Specific examples of the compound include 2-mercapto-4-phenylimidazole, 2-mercapto-1-benzylimidazole, 2-mercapto-1-butyl-benzimidazole, 1,3-dibenzyl-imidazolidine-2-thione, 2-mercapto-4-phenylthiazole, 3-butyl-benzothiazoline-2-thione, 3-dodecyl-benzothiazoline-2-thione, 2-mercapto-4,5-diphenyloxazole, 3-pentyl-benzoxazoline-2 -Thione, 1-phenyl-3-methylpyrazolin-5-thione, 3-mercapto-4-allyl-5-pentadecyl-1,2,4-triazole, 3-mercapto-5-nonyl-1,2,4-triazole 3-mercapto-4-acetamido-5-heptyl-1,2,4-tria 3-mercapto-4-amino-5-heptadecyl-1,2,4-triazole, 2-mercapto-5-phenyl-1,3,4-thiadiazole, 2-mercapto-5-n-heptyl-oxa Thiazole, 2-mercapto-5-n-heptyl-oxadiazole, 2-mercapto-5-phenyl-1,3,4-oxadiazole, 2-heptadecyl-5-phenyl-1,3,4-oxadi Azole, 5-mercapto-1-phenyl-tetrazole, 3-mercapto-4-methyl-6-phenyl-pyridazine, 2-mercapto-5,6-diphenyl-pyrazine, 2-mercapto-4,6-diphenyl-1, 3,5-triazine, 2-amino-4-mercapto-6-benzyl-1,3,5-triazine, and the like, but are not limited thereto. Not.

  The developer used in the present invention contains, in addition to the above compounds, thickeners such as hydroxymethylcellulose and carboxymethylcellulose, antifoggants such as potassium bromide, and compounds described in JP-A-47-26201. be able to.

  When the developer of the present invention is applied to a coating and developing system, it is preferable to contain a surfactant for the purpose of reducing the surface tension. Specific examples of the surfactant include, for example, polyoxyethylene glycol alkyl ether, polyoxypropylene glycol alkyl ether, polyoxyethylene glycol sorbitan alkyl ester, polyoxyethylene acetylenic glycol ether, polyoxyethylene sorbitan monooleate and the like. Nonionic surfactant, polyoxyethylene glycol alkyl sulfuric acid, polyoxypropylene glycol alkyl sulfuric acid, polyoxyethylene glycol alkyl carboxylic acid, polyoxypropylene glycol alkyl carboxylic acid, polyoxyethylene glycol alkyl phosphoric acid, polyoxypropylene glycol alkyl phosphoric acid Anionic surfactants such as acids, lauryldimethylaminoacetic acid betaine, coconut oil fatty acid amidopropyldi Chiruamino betaine, amphoteric surfactants such as coconut oil fatty acid amide propyl dimethyl hydroxypropyl sulfopropyl betaine.

  In the plate making method of the present invention, it is preferable to carry out a stabilization process subsequent to the development process. The main function of the stabilization process is to neutralize the alkaline plate surface in the development process. Therefore, the pH of the stabilizer is preferably adjusted from neutral to acidic. The pH of the stabilizing solution is preferably 7.5 or less, more preferably 4-7.

  It is preferable that the stabilizing solution is further provided with a buffering performance near the pH. As the buffer, it is preferable to use amines such as phosphoric acid and its salts or triethanolamine. When using a phosphate as a buffering agent, the content is 0.05 mol / L or more, preferably 0.1 to 1.0 mol / L in the use solution. As the phosphate, potassium salt, sodium salt, ammonium salt, or a salt with amines such as triethanolamine described above can be used.

  Similarly to the developer, the stabilizer may contain a compound having a mercapto group or a thione group as a lipophilic agent in order to improve the ink acceptability of the silver image area. As these compounds, the same compounds as in the developer can be used in the stabilizer.

A preferred embodiment of a lithographic printing plate to which the silver complex diffusion transfer method used in the present invention is applied is a lithographic printing plate in which at least a subbing layer, a silver halide emulsion layer and a physical development nucleus layer are successively coated on a support. It is. The total gelatin amount of these sequentially applied layers is preferably ¹ to 4.5 g / m ² .

If the total gelatin amount is less than 1 g / m ² , the coating strength required for a printing plate may not be obtained. On the other hand, if it exceeds 4.5 g / m ² , ink acceptability and ink detachment during printing are slow, and printing workability may be reduced.

  The DTR lithographic printing plate of the present invention contains gelatin as a binder, and the containing layer is an undercoat layer, an emulsion layer, or a physical development nucleus layer. Part of gelatin is starch, dextrin, albumin, sodium alginate, hydroxyl ethyl cellulose, gum arabic, polyvinyl alcohol, polyvinyl pyrrolidone, carboxymethyl cellulose, polyacrylamide, styrene-maleic anhydride copolymer, polyvinyl rutile ether-maleic anhydride. It can also be substituted with one or more hydrophilic polymers such as copolymers.

  These gelatin-containing layers can be hardened with a gelatin hardener. Examples of gelatin hardeners include inorganic compounds such as chromium alum, aldehydes such as formalin, gliogizar, malealdehyde, and glutaraldehyde, urea, ethylene urea, mucochloric acid, and 2,3-dihydroxy-1,4. Aldehyde equivalents such as dioxane, compounds having active halogen such as 2,4-dichloro-6-hydroxy-s-triazine and 2,4-dihydroxy-6-chloro-s-triazine, divinyl sulfone, divinyl Ketones, N, N, N-triacloylhexahydrotriazine, compounds having two or more active three-membered ethyleneimino groups or epoxy groups in the molecule, dialdehyde starch as a polymer hardener, etc. One or two or more of these various compounds can be used.

  The hardener can be added to all layers, or it can be added to some or only one layer. Of course, the diffusible hardener can be added to only one layer when two or more layers are applied simultaneously. The addition method can be added at the time of producing the coating liquid or in-line at the time of coating.

  In the present invention, it is preferable to use a matting agent having an average particle size of 0.3 to 8.0 μm in the constituent layer on the photosensitive surface side of the DTR lithographic printing plate. Examples of the matting agent used in the present invention include silica particles and organic particles such as styrene.

In the present invention, the matting agent is preferably contained in an undercoat layer between the support and the silver halide emulsion layer. The addition amount of the matting agent varies depending on various conditions, but is preferably included in the constituent layer on the photosensitive surface side in the range of 0.1 to 5.0 g / m ² , preferably 0.3 to 3. The range is 5 g / m ² .

  The undercoat layer can contain a pigment such as carbon black, a dye or the like for the purpose of preventing halation. Furthermore, photographic additives such as developing agents can also be included. The undercoat layer may be an undercoat layer as described in JP-A-48-5503, JP-A-48-100203, and JP-A-49-16507.

  As the silver halide emulsion of the DTR lithographic printing plate used in the practice of the present invention, silver chloride, silver bromide, silver chlorobromide, silver chloroiodide, silver chlorobromoiodide, etc. can be used, preferably silver chloride is used. 70 mol% or more of silver halide. Silver halide emulsions containing these contain spectral sensitizers (light sources, spectral sensitizing dyes depending on the application), gelatin hardeners, coating aids, antifoggants, plasticizers, developers, matting agents, etc. Can do.

  As the support used in the lithographic printing plate of the present invention, paper, various films, plastic, paper coated with a resin-like substance, metal, or the like can be used.

  The physical development nuclei used in the physical development nuclei layer are well known as examples of this type of chemical, and include metals such as antimony, bismuth, cadmium, cobalt, palladium, nickel, silver, lead, zinc, and sulfides thereof. Can be used. Also, physical development nuclei described in JP-A-5-265164 can be used. The physical development nucleus layer may also contain a developing agent or a binder.

  Moreover, the printing method of the lithographic printing plate produced by this invention or the desensitizing liquid used, the moisturizing liquid, etc. can be based on a generally well-known method.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, unless it deviates from the meaning of this invention, it is not limited to these.

(Example 1)
As a developing device for making a DTR planographic printing plate, SDP-Eco1630IIIR (coating and developing method) commercially available from Mitsubishi Paper Industries Co., Ltd. was used. This apparatus is an automatic plate making apparatus that uses a red laser having a wavelength of 630 nm to form a latent image of a data image on a DTR printing plate by digital exposure using a scanning exposure method, and subsequently performs development and stabilization processing to make a plate. The application amount of the developer is 30 to 50 ml, and the time from the application of the developer to the contact with the stabilizing solution is 12 seconds.

The DTR lithographic printing plate is provided with a matting layer containing ² g / m ² of titanium oxide and a silica matting agent having an average particle size of 5 μm as a backing layer on one side of a 175 μm-thick polyethylene terephthalate base. An undercoat layer (adjusted to pH 4.5) containing a silica matting agent containing carbon black and containing 20% by mass of an average particle diameter of 7 μm with respect to photographic gelatin, and after chemical sensitization with hypo and gold compounds, 2 -A silver halide emulsion layer (adjusted to pH 4.5) containing mercaptobenzoic acid is provided.

  The silver halide emulsion was dye sensitized to red by a known method.

The gelatin of the undercoat layer was applied at 3.0 g / m ² , the gelatin of the silver halide emulsion layer was 1.0 g / m ² , and the silver halide converted to silver nitrate was 1.0 g / m ² . The undercoat layer and the emulsion layer contain 30 mg of formalin as a hardener with respect to 1 g of gelatin.

Gelatin 0.105 g / ^{m 2} dimethoxy phenidone subbing layer, a silver halide emulsion layer 0.024 g / ^{m 2,} the physical development nuclei layer contains 0.006 g / ^{m 2.}

After coating the undercoat layer and the silver halide emulsion layer, the mixture was heated at 50 ° C. for 2 days, and the core coating solution described in Example 1 of JP-A-57-86835 was coated on the silver halide emulsion layer. . The physical development nucleus layer thus provided contains 0.001 g / m ² of palladium sulfide.

  The DTR lithographic printing plate thus obtained was rolled into a width of 400 mm and a length of 61 m, loaded into the SDP-Eco1630IIIR automatic plate making apparatus, subjected to exposure and plate making processing, and stored at room temperature for 14 days. A print evaluation was performed.

The developer used in the plate making process is shown below.
<Developer A>
Sodium hydroxide 15g
Potassium hydroxide 20g
Anhydrous sodium sulfite 50g
0.4 g of 2-mercapto-5-n-heptyloxadiazole
Thiosalicylic acid 0.5g
Polyoxyethylene acetylenic glycol ether 0.2g
Polyoxyethylene sorbitan monooleate 0.25g
Coconut oil fatty acid amidopropyldimethylhydroxysulfopropylbetaine 0.5g
Make up to 1 liter with pure water.
The pH was adjusted to 13.7 with potassium hydroxide.

<Developer B>
Developer B was obtained in the same manner as Developer A except that 115 mmol of N- (2-aminoethyl) ethanolamine was further added.

<Developer C>
In the preparation of the developer A, a developer C was obtained in the same manner as the developer A except that 80 mmol of the compound 1-1 was further added.

<Developer D>
In the preparation of the developer A, a developer D was obtained in the same manner as the developer A except that 10 mmol of 3,6-dithia-1,8-octanediol was further added.

<Developer E>
In the preparation of the developer A, a developer E was obtained in the same manner as the developer A except that 80 mmol of ethylenediamine and 80 mmol of the compound 1-1 were added.

<Developer F>
Developer F was obtained in the same manner as Developer A except that 80 mmol of ethylenediamine and 10 mmol of 3,6-dithia-1,8-octanediol were further added in the preparation of Developer A.

<Developer G>
In the production of the developer A, a developer G was obtained in the same manner as the developer A except that 80 mmol of triethylenetetraamine and 80 mmol of the compound 1-1 were added.

<Developer H>
In the preparation of the developer A, a developer H was prepared in the same manner as the developer A except that 96 mmol of N- (2-aminoethyl) ethanolamine and 27 mmol of 3,6-dithia-1,8-octanediol were further added. Got.

<Developer I>
Developer I was obtained in the same manner as Developer A except that 80 mmol of Compound 1-1 and 10 mmol of 3,6-dithia-1,8-octanediol were further added in the preparation of Developer A.

<Developer J>
In the production of the developer A, a developer J was obtained in the same manner as the developer A except that 80 mmol of the compound 1-1 and 40 mmol of 3,6-dithia-1,8-octanediol were added.

<Developer K>
Developer K was obtained in the same manner as Developer A, except that 80 mmol of Compound 1-1 and 80 mmol of 3,6-dithia-1,8-octanediol were further added.

<Developer L>
In the preparation of the developer A, a developer L was obtained in the same manner as the developer A except that 80 mmol of the compound 1-1 and 120 mmol of 3,6-dithia-1,8-octanediol were further added.

<Developer M>
Developer M was obtained in the same manner as Developer A, except that 700 mmol of Compound 1-1 and 10 mmol of 3,6-dithia-1,8-octanediol were further added.

<Developer N>
In the preparation of the developer A, except that 80 mmol of the compound 1-1, 10 mmol of 3,6-dithia-1,8-octanediol, and 30 mmol of N- (2-aminoethyl) ethanolamine were further added. In the same manner as Developer A, Developer N was obtained.

<Developer O>
In the preparation of the developer A, except that 80 mmol of the compound 1-1, 10 mmol of 3,6-dithia-1,8-octanediol, and 35 mmol of N- (2-aminoethyl) ethanolamine were further added. In the same manner as Developer A, Developer O was obtained.

<Developer P>
Developer P was obtained in the same manner as Developer A except that 80 mmol of Compound 1-1 and 10 mmol of 2,2′-thiodiethanol were further added in the preparation of Developer A.

<Developer Q>
Developer Q was obtained in the same manner as Developer A, except that 80 mmol of Compound 1-5 and 10 mmol of 3,6-dithia-1,8-octanediol were further added.

The stabilizer shown below was used.
<Stabilizer>
Primary potassium phosphate 20g
Triethanolamine 5g
0.4 g of 2-mercapto-5-n-heptyloxadiazole
The pH is adjusted to 6 with phosphoric acid and adjusted to 1 L with pure water.

  The printing test of the planographic printing plate is performed by a printing press (RYOBI 660H RYOBI660H), ink (DIC Corporation Space Color Fusion G Black Normal Type and Space Color Fusion G Red Normal Type), and dampening liquid (Fuji Film Co., Ltd.). Ecolite 2 manufactured at 0.5% by mass) was used. In printing using Space Color Fusion G black normal type ink, 20,000 sheets are printed by a normal printing method, a printing durability test is performed to determine the disappearance degree of the silver image portion, and Space Color Fusion G Red normal type ink is printed. In the printing using, an ink detachment test was carried out to determine the recovery of ink stains in the non-image area by performing normal printing after the ink was once deposited on the entire surface of the non-image area.

  In the printing durability test, evaluation was performed based on the change rate of the dot area of 175 lines and 5% output at 2400 dpi. The printing start was set to 100%, and when the image area of 80% or more was maintained at the time of printing 20,000 sheets, it was marked as ◯, when it was 50% or more and less than 80%, and when it decreased to less than 50%. In addition, in the ink detachment test, if the above-mentioned series of printing methods is set as one set and the ink stain on the non-image area is recovered even when it is repeated 5 sets or more, the ink stain is obtained with 3 sets or 4 sets. When no recovery occurred, Δ was evaluated, and when it did not recover after printing of 2 sets or less, it was evaluated as ×. The results are shown in Table 1.

(Example 2)
The test was conducted in the same manner as in Example 1 except that the automatic plate making apparatus used for plate making of the lithographic printing plate of Example 1 was changed to FREDIA (immersion development method) commercially available from Mitsubishi Paper Corporation.

  As a result of plate-making and printing, the same results as in Example 1 were obtained, so that the plate-making method of the present invention was proved to be useful in the immersion development method.

  As is clear from the above results, according to the present invention, a lithographic printing plate in which no ink detachment failure occurs in the non-image area and printing failure does not occur even when stored for 14 days after plate making is obtained. You can see that

Claims (1)

A lithographic printing plate having at least a silver halide emulsion layer and a physical development nucleus layer in this order on a support, a piperazine compound or aminoalkyl having an alkanolamine compound content of 30 mmol / L or less and having an aminoalkyl group Developed with a developer containing a morpholine compound having a thioether compound and a piperazine compound having an aminoalkyl group or a morpholine compound having an aminoalkyl group that is 2 to 8 times (molar ratio) of the thioether compound The plate making method of the lithographic printing plate to be processed.