JP2013025017A - Method of developing waterless lithographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a waterless lithographic printing plate having excellent ink receptivity by a developing method not including a step of performing post-treatment with a post-treatment solution containing an organic solvent.SOLUTION: A method of developing a waterless lithographic printing plate having at least a photosensitive layer, a thermosensitive layer, and a silicone rubber layer on a substrate includes a step (1) of subjecting the waterless lithographic printing plate to pre-treatment with a pre-treatment solution containing 95 percent by weight of ethylene glycol derivative expressed by a general formula (I): R-(OCHCH)-OH and a step (2) of developing the waterless lithographic printing plate after pre-treatment with a developer containing water but does not include a step of performing post-treatment with a post-treatment solution containing an organic solvent. In the general formula, R represents a hydrogen atom or an alkyl group with 1 to 5 carbon atoms and n represents an integer of 1 to 5.

Description

  The present invention relates to a method for developing a waterless lithographic printing plate having at least a photosensitive layer or a heat-sensitive layer and a silicone rubber layer on a substrate.

  Since the waterless lithographic printing plate does not require water at the time of printing, it has features such as simplicity that does not require skill. Further, in recent years, many direct-drawing waterless lithographic printing plates capable of producing a so-called direct-drawing type (CTP) plate making direct offset printing plate from original electronic data without using a plate-making film have been studied. Direct-drawing plate making has features such as simplicity that does not require skill, quickness to obtain printing plates in a short time, and rationality that can be selected from various systems according to quality and cost. .

  Recently, direct-drawing waterless lithographic printing plates have been developed that can be developed with an automatic developing machine used for conventional waterless lithographic printing plates that use a negative or positive film during exposure. In addition, with respect to the treatment liquid used at the time of plate making, as a treatment liquid capable of treating any of negative-type waterless lithographic printing plates, positive-type waterless lithographic printing plates, and direct-drawing waterless lithographic printing plates, amine compounds and What mainly consists of a polar solvent is disclosed (for example, refer patent document 1). Furthermore, amino groups and hydroxyl groups are used as processing solutions that can be processed without being affected by fluctuations in the plate-making conditions, even for positive and direct-drawing waterless lithographic printing plates that are easily affected by fluctuations in the plate-making conditions. A compound mainly composed of a compound having an ethylene glycol derivative, and a polar solvent is disclosed (for example, see Patent Document 2).

  However, when these processing solutions are used for a long time, the amine compound in the composition is consumed and the image reproducibility is lowered. Therefore, an ethylene glycol derivative and an amine compound having two or more primary amino groups in one molecule are used as a processing solution that can suppress image reproducibility degradation due to fluctuations in the content of the amine compound and can be stably processed for a long period of time. A treatment liquid containing the same has been developed (see, for example, Patent Document 3).

JP 2003-167356 A JP 2005-338580 A JP 2008-015065 A

  The development method of a waterless lithographic printing plate generally has the steps of pretreatment, development and post-treatment in this order. By the post-treatment process using a post-treatment liquid containing an organic solvent, ink repelling components such as a silicone rubber layer remaining in the image area are reduced, and the ink inking property of the image area is improved. However, recently, from the viewpoint of reducing the environmental burden, there is a demand for a development method that refrains from using an organic solvent and does not have a post-processing step using the organic solvent. In the developing method that does not have a post-processing step using an organic solvent, the ink repellent component tends to remain in the image area, and there is a problem that the ink inking property is reduced as compared with the developing method that has a post-processing step using an organic solvent. .

  In view of the above-described problems of the prior art, the present invention provides a waterless lithographic printing plate having excellent ink setting properties by a development method that does not include a step of post-processing with a post-processing liquid containing an organic solvent. Objective.

The present invention relates to a method for developing a waterless lithographic printing plate having at least a photosensitive layer or a heat-sensitive layer and a silicone rubber layer on a substrate, wherein (1) the waterless lithographic printing plate is represented by the following general formula (I): A step of pretreating with a pretreatment liquid containing 95% by weight or more of an ethylene glycol derivative, and (2) a step of developing the waterless planographic printing plate after the pretreatment with a developer containing water, It is a developing method of a waterless lithographic printing plate characterized by having no post-treatment step with the post-treatment liquid contained.
R— (OCH ₂ CH ₂ ) _n —OH (I)
(In the general formula (I), R represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. N represents an integer of 1 to 5)

  By using the development method of the present invention, without using a post-treatment liquid containing an organic solvent, the ink repellent component is prevented from remaining in the image area, and a waterless lithographic printing plate having excellent ink fillability is obtained. be able to.

  The method for developing a waterless lithographic printing plate of the present invention is used in a plate making process for exposing and developing a waterless lithographic printing plate. The waterless lithographic printing plate developed by the developing method of the present invention has at least a photosensitive layer or a heat-sensitive layer and a silicone rubber layer in this order on a substrate. A primer layer may be provided between the substrate and the photosensitive layer or the heat-sensitive layer, and another layer may be further provided. From the viewpoint of non-image area peeling resistance, a waterless lithographic printing plate having a heat sensitive layer is preferred. More specifically, waterless planographic printing plates described in JP2009-186626A and JP2005-309126A can be mentioned.

  Since the waterless lithographic development method of the present invention does not have a post-treatment step using a post-treatment liquid containing an organic solvent from the viewpoint of reducing environmental burden, it is generally performed for conventional plate inspection. There is no dyeing process of the image area in the processing process. For this reason, a waterless lithographic printing plate that can perform plate inspection without requiring a dyeing step is more preferred. Examples of the plate inspection property of the waterless lithographic printing plate include visual plate inspection property by visual observation and device plate inspection property by a halftone dot area ratio measuring device. In general, since device inspection is more severe than visual inspection, a waterless lithographic printing plate having good device inspection is often good in visual inspection. As a waterless lithographic printing plate that can be inspected without requiring a dyeing step, for example, it has a heat-sensitive layer (photosensitive layer) that changes its color when the heat-sensitive layer (photosensitive layer) absorbs heat during exposure. Waterless lithographic printing plates and waterless lithographic printing plates in which the silicone rubber layer contains a colored pigment are exemplified.

  Among these, a waterless lithographic printing plate in which the silicone rubber layer contains a colored pigment is preferably used. From the viewpoint of further improving the instrument plate inspection property and visual plate inspection property, a waterless lithographic printing plate containing a colored pigment that absorbs green light or red light is more preferable. Colored pigments that absorb green or red light include bengara (ferric oxide), chromium oxide, cobalt blue, iron black, viridian, vermilion, cadmium red, bitumen, molybdenum red, hydrous oxalate, ultramarine, garnet , Manganese violet, carbon black, extender pigments dyed with rhodamine, methyl violet, peacock blue, alkali blue, malachite green, alizarin and other dyes, alkali blue, aniline black, resol red, lake red C, brilliant carmine 6B, Watch Young Red, Bordeaux 10B, Para Red, Lake Red 4R, Naphthol Red, Chromophthal Scarlet RN, Phthalocyanine Blue, Fast Sky Blue, Phthalocyanine Green, Anthraquinone Pigment Perylene red, thioindigo red, indanthrone blue, quinacridone red, quinacridone violet, dioxazine violet, include naphthol green B. Two or more of these may be contained. Examples of the waterless lithographic printing plate in which the silicone rubber layer contains a colored pigment include a waterless lithographic printing plate described in International Publication No. 2008/56588.

  Next, a method for making a waterless lithographic printing plate will be described. In the case of a waterless lithographic printing plate having at least a photosensitive layer and a silicone rubber layer in this order on a substrate, an original film is usually placed on a protective film, image exposure is performed with actinic rays, and then the protective film is peeled off The image can be formed by developing. In addition, in the case of a so-called direct-drawing waterless lithographic printing plate having at least a heat-sensitive layer and a silicone rubber layer in this order on the substrate, the plate having the protective film is left as it is or after the protective film is peeled off, the protective film For a plate having no ink, the image is exposed directly to the ink repellent layer with a laser beam. An image having a protective film can be formed by peeling and then developing with a hand development or developing device. Specific examples of the developing device include TWL-650 series, TWL-860 series, TWL-1160 series (manufactured by Toray Industries, Inc.), TWL-860CF, TWL-1160CF (manufactured by Toyo Shoji Co., Ltd.), Examples thereof include an automatic developing machine disclosed in Japanese Patent No. 2265, Japanese Patent Laid-Open No. 5-2272, Japanese Patent Laid-Open No. 5-6000, and the like.

The present invention relates to a developing method in the plate making method of the waterless lithographic printing plate, and (1) the waterless lithographic printing plate contains 95% by weight or more of an ethylene glycol derivative represented by the following general formula (I) A step of pretreating with a pretreatment liquid, and (2) a step of developing the waterless lithographic printing plate after pretreatment with a developer containing water, and a step of posttreatment with a posttreatment liquid containing an organic solvent. It is characterized by not having.
R— (OCH ₂ CH ₂ ) _n —OH (I)
(In the general formula (I), R represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. N represents an integer of 1 to 5)
First, (1) a step of pretreating a waterless lithographic printing plate with a pretreatment liquid containing 95% by weight or more of the ethylene glycol derivative represented by the general formula (I) will be described. The pretreatment step is a step that is performed prior to development after exposure of the waterless lithographic printing plate to swell the silicone rubber layer and dissolve the heat-sensitive layer or photosensitive layer in the portion that later becomes the image area. The pretreatment liquid in the present invention contains 95% by weight or more of the ethylene glycol derivative represented by the general formula (I). In a development method that does not include a step of post-processing with a post-processing solution containing an organic solvent, if the ethylene glycol derivative content is less than 95% by weight, ink repellent components such as a silicone rubber layer tend to remain in the image area. Ink depositability is reduced as compared with a developing method having a post-processing step. The ethylene glycol derivative content is preferably 96% by weight or more in order to further improve the ink fillability of the image area. On the other hand, in order to suppress peeling of the silicone rubber layer in the non-image area, the ethylene glycol derivative content is preferably 99.9% by weight or less.

  Examples of the ethylene glycol derivative represented by the general formula (I) include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, Ethylene glycol monoisobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monoisobutyl ether triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol mono Isopropyl ether, triethylene glycol monobutyl ether. Two or more of these may be contained. n is preferably 1 to 4, and R is preferably hydrogen, a methyl group, an ethyl group, a propyl group or a butyl group, more preferably hydrogen.

  Moreover, in order to suppress the silicone rubber layer peeling of the non-image area by the pretreatment liquid, it is preferable to contain an amine compound having two or more primary amino groups in one molecule together with the ethylene glycol derivative. The amine compound is preferably contained in the pretreatment liquid in an amount of 0.1% by weight or more. On the other hand, the amine compound content is preferably 5% by weight or less, more preferably 4% by weight or less, from the viewpoint of ink fillability in the image area.

  Examples of the amine compound that is contained simultaneously with the ethylene glycol derivative include ethylenediamine, 1,2-propanediamine, 1,3-propanediamine, 1,2-diaminobutane, 1,4-diaminobutane, 2,3-diaminobutane, hexa Methylenediamine, diethylenetriamine, triethylenetetramine, bis (3-aminopropyl) ether, iminobispropylamine, methyliminobispropylamine, bis (3-aminoprooxy) ethane, N, N-bis (3-aminopropyl) -1,3-propylenediamine, N, N-bis (3-aminopropyl) -1,4-butylenediamine, polyoxypropylenediamine, 1,2,5-pentatriamine, 2,3,6-triaminopyridine , Polyoxyalkylenetriamine, α, ω-bis ( 3-aminopropyl) diethylene glycol ether, α, ω-bis (3-aminopropyl) polyethylene glycol ether, 1,2,4,5-benzenetetramine, and the like. It is not limited to these. Among these, those having a molecular weight of 150 or more are preferable from the viewpoint of volatility.

  The pretreatment liquid in the present invention may optionally contain a propylene glycol solvent, a dye, a dye auxiliary agent, a surfactant, an antifoaming agent and the like. Further, the pretreatment liquid may be used as a developer as it is.

  The pretreatment is performed by treating the waterless planographic printing plate after exposure with the pretreatment liquid. Examples of the treatment method include a method of immersing a waterless lithographic printing plate after exposure in the pretreatment liquid, a method of wetting the plate surface by applying the pretreatment liquid to the waterless lithographic printing plate surface after exposure with a shower, and the like. It is done.

  In the method for developing a waterless lithographic printing plate according to the present invention, it is preferable to keep the temperature of the pretreatment liquid in the pretreatment step constant from the viewpoint of further stabilizing image reproducibility and ink deposition. From the viewpoint of improving developability, the temperature of the pretreatment liquid is preferably 35 ° C. or higher. Moreover, from a viewpoint of suppressing peeling of a photosensitive layer or a thermosensitive layer, 50 ° C. or less is more preferable.

  In addition, it is preferable to keep the pretreatment time constant from the viewpoint of further stabilizing image reproducibility and ink fillability. The appropriate treatment time varies depending on the temperature of the treatment liquid, but is preferably 20 seconds or longer. If it is 20 seconds or longer, the processing time can be easily managed, and stable development can be easily performed. Moreover, 90 seconds or less are preferable from the viewpoint of workability. In particular, when an automatic processor is used, it is preferable that the pretreatment time is short.

  Next, (2) a step of developing the waterless planographic printing plate after the pretreatment with a developer containing water will be described. The development step is a step of forming an image by rubbing the surface of the waterless lithographic printing plate with a brush or cotton pad in the presence of the pretreatment liquid or water. When an image is formed by positive working, the unexposed portion of the silicone rubber layer is removed, and the underlying photosensitive layer or heat sensitive layer is exposed to form an ink deposit (image portion). When an image is formed by negative working, the exposed silicone rubber layer is removed to expose the underlying photosensitive layer or heat-sensitive layer, thereby forming an ink deposit (image portion). From the viewpoint of reducing the environmental load, it is preferable to use water as the developer. Development may be performed by spraying warm water or water vapor onto a waterless lithographic printing plate. In order to improve developability, a solution obtained by adding a small amount of the pretreatment liquid to water may be used as the developer. The temperature of the developer in the development step may be arbitrary, but is preferably 10 ° C to 50 ° C.

  Although the development method of the present invention does not include a step of post-processing with a post-treatment liquid containing an organic solvent, a post-processing step using a post-treatment liquid that does not contain an organic solvent may be provided after the development step. In the post-processing step, the surface of the waterless lithographic printing plate is rubbed with a brush or a cotton pad to remove ink repellent components in the image area that could not be removed in the development step. When installing a brush in a post-processing process, it is preferable to reverse-rotate a brush with respect to a plate-passing direction from a viewpoint of reducing the ink repelling component which remains. Water may be used for the post-treatment liquid, and other aqueous acids, antifoaming agents, and plasticizers may be optionally added, but water is preferably used from the viewpoint of reducing environmental burden. Although the temperature of the post-processing liquid in a post-processing process may be arbitrary, 10 to 50 degreeC is preferable.

  If the pre-treatment liquid and post-treatment liquid remain infiltrated into the waterless lithographic printing plate surface, the silicone rubber layer in the non-image area and the photosensitive layer or heat-sensitive layer in the image area may easily peel off over time. Therefore, a water washing step of washing off the pretreatment liquid and the posttreatment liquid from the waterless lithographic printing plate surface using water may be provided. The temperature of the washing water may be arbitrary, but is preferably 10 ° C to 50 ° C.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these.

Example 1
First, a waterless lithographic printing plate precursor having a colored silicone layer having a size of 560 mm long and 670 mm wide was prepared by the following method. The following primer layer composition liquid is applied onto a 0.24 mm thick degreased aluminum substrate (Mitsubishi Aluminum Co., Ltd.) and dried at 200 ° C. for 90 seconds to provide a primer layer having a thickness of 10 g / m ^2. It was.

<Primer layer composition liquid>
(A) “Titanium Master” (registered trademark) 7A-1331 (Sumika Color Co., Ltd.): 75 parts by weight (b) Polyurethane: “Samprene” (registered trademark) LQ-T1331D (manufactured by Sanyo Chemical Industries, Ltd.) : 78 parts by weight (c) Epoxy resin: Epoxy 1010 DMF (manufactured by Petrochemicals): 36 parts by weight (d) Leveling agent: “Disparon” (registered trademark) LC951 (manufactured by Enomoto Kasei Co., Ltd.): 1 part by weight (E) N, N-dimethylformamide: 29 parts by weight (f) Methyl ethyl ketone: 77 parts by weight

Subsequently, the following heat sensitive layer composition liquid was apply | coated on the said primer layer, and it heated at 120 degreeC for 90 second, and provided the heat sensitive layer with a film thickness of 1.5 g / m < ² >.

<Thermosensitive layer composition liquid>
(A) Infrared absorbing dye: NK8876 (manufactured by Hayashibara Biochemical Laboratories): 10 parts by weight (b) Titanium chelate: “Narsem” (registered trademark) titanium (manufactured by Nippon Chemical Industry Co., Ltd., solid content concentration: (40% by weight): 10 parts by weight (c) phenol formaldehyde novolak resin: tetrahydrofuran solution (solid content: 40% by weight) of “Sumilite Resin” (registered trademark) PR-50731 (manufactured by Sumitomo Bakelite Co., Ltd.): 68% by weight Part (d) Phenolformaldehyde novolak resin: “Sumilite Resin” (registered trademark) PR-53195 (manufactured by Sumitomo Bakelite Co., Ltd.) in tetrahydrofuran (solid content: 40% by weight): 23 parts by weight (e) Polyurethane: “ "Samprene" (registered trademark) LQ-T1331D (manufactured by Sanyo Chemical Industries): 5 parts by weight (f) Mer: SP-Y08 (manufactured by Toray Fine Chemicals Co., Ltd.): 18 parts by weight (g) Tetrahydrofuran: 100 parts by weight (h) ethanol: 10 parts by weight (i) Ethyl diglycol 43 parts by weight

Next, the following colored pigment-containing silicone diluent prepared immediately before coating was coated on the heat-sensitive layer and heated at 130 ° C. for 90 seconds to provide a silicone rubber layer having a thickness of 2.0 g / m ² . The silicone rubber layer immediately after heating was completely cured. On the silicone rubber layer immediately after heating, a 6 μm-thick polypropylene film: “Trephan” (registered trademark) (manufactured by Toray Industries, Inc.) was laminated to obtain a negative waterless CTP lithographic printing plate precursor.

<Colored pigment-containing silicone diluent>
The following (a) to (c) were mixed in this order to obtain a colored pigment dispersion dilution.
(A) “Isopar” (registered trademark) E (manufactured by ExxonMobil): 342 parts by weight (b) Vinyltris (methylethylketooxyimino) silane: 1 part by weight (c) Colored pigment (bitumen): “Blue Master” (Registered trademark) 5A1258 (manufactured by Sumika Color Co., Ltd.): 10 parts by weight

Subsequently, the following (d)-(h) was mixed in another container, and the silicone dilution liquid was obtained.
(D) "Isopar" (registered trademark) E (manufactured by ExxonMobil): 701 parts by weight (e) DOW CORNING TORAY CY54-050BASE (manufactured by Toray Dow Corning Co., Ltd.): 20 parts by weight (f) CY51 -046 (manufactured by Amax Co., Ltd.): 80 parts by weight (g) Vinyltris (methylethylketooxyimino) silane: 3 parts by weight (h) "SRX" 212 (manufactured by Toray Dow Corning Co., Ltd.): 7 parts by weight

  While stirring the colored pigment dispersion diluted solution prepared in advance, the silicone diluted solution prepared in a separate container was mixed at a liquid weight ratio of 1: 6.5 to obtain a colored pigment-containing silicone diluted solution. .

  The negative waterless CTP lithographic printing plate precursor is mounted on a platemaking machine Trendsetter 800 Quantum (manufactured by Kodak Co., Ltd.), and a semiconductor laser is used to obtain an image of 2400 dpi, 175 lines / inch, 50% using an exposure amount of 10.5 W. Exposed. The polypropylene film on the surface is peeled off from the exposed plate, and a waterless lithographic printing plate automatic developing machine TWL-1160F (Toray Industries, Inc.) is set at a pretreatment liquid temperature of 45 ° C., a pretreatment time of 40 seconds, and a developer temperature of 25 ° C. )), Pre-treatment, development, post-treatment, and water washing were performed to obtain a printing plate.

<Pretreatment liquid-1> having the following composition was put in the pretreatment tank, and water was put in the developing tank, the posttreatment tank, and the washing tank.
<Pretreatment liquid-1>
(1) Diethylene glycol 100.0% by weight

  The obtained printing plate is attached to a sheet-fed offset printing press LITHRONE 26 (manufactured by Komori Corporation), and a water-free lithographic ink, Acquares Echo Neo Ai LZ (manufactured by Toyo Ink Co., Ltd.) is used to print 100 By printing on coated paper (top coat 62.5 kg / (636 mm × 939 mm)) so that the ink density of the% pattern is 1.10 to 1.30, and measuring the ink density of the 50% pattern of the printed material Ink fillability was evaluated. The ink density was 0.41, and good ink landing property was exhibited. The evaluation results are shown in Table 1. In this evaluation, if the ink concentration is 0.25 or more, it can be said that the ink inking property is good. Note that GretagMacbeth SpectroEye (manufactured by X-Rite Co., Ltd.) was used for measuring the ink density of the printed matter. Moreover, when the printing plate obtained by the said pre-processing, image development, post-processing, and water washing was visually observed, peeling of the non-image area was evaluated.

(Example 2)
Except for using <Pretreatment liquid-2> having the following composition in the pretreatment tank of the automatic developing machine, plate making and printing were carried out in the same manner as in Example 1 to evaluate ink adhesion and non-image area peeling. As a result, good ink deposition was exhibited and non-image area peeling occurred. The evaluation results are shown in Table 1.
<Pretreatment liquid-2>
(1) Diethylene glycol monobutyl ether 100.0% by weight

(Examples 3 to 11)
Except for using <Pretreatment liquid-3> to <Pretreatment liquid-11> having the following composition in the pretreatment tank of the automatic processor, plate-making / printing was carried out in the same manner as in Example 1 to obtain ink inking properties and When evaluation of non-image area peeling was performed, good ink deposition was shown, and non-image area peeling occurred in Example 3, but not in Examples 4 to 11. The evaluation results are shown in Table 1.
<Pretreatment liquid-3>
(1) Triethylene glycol 100.0% by weight
<Pretreatment liquid-4>
(1) 99.9% by weight of triethylene glycol
(2) Polyoxyalkylene triamine (“Jeffamine” (registered trademark) T-403 (manufactured by Huntsman)) 0.1% by weight
<Pretreatment liquid-5>
(1) 99.5% by weight of triethylene glycol
(2) Polyoxyalkylene triamine (“Jeffamine” (registered trademark) T-403 (manufactured by Huntsman)) 0.5% by weight
<Pretreatment liquid-6>
(1) Triethylene glycol 99.0% by weight
(2) Polyoxyalkylene triamine (“Jeffamine” (registered trademark) T-403 (manufactured by Huntsman)) 1.0% by weight
<Pretreatment liquid-7>
(1) Triethylene glycol 98.0% by weight
(2) Polyoxyalkylene triamine (“Jeffamine” (registered trademark) T-403 (manufactured by Huntsman)) 2.0% by weight
<Pretreatment liquid-8>
(1) 97.0% by weight of triethylene glycol
(2) Polyoxyalkylene triamine (“Jeffamine” (registered trademark) T-403 (manufactured by Huntsman)) 3.0% by weight
<Pretreatment liquid-9>
(1) Triethylene glycol 96.0% by weight
(2) Polyoxyalkylene triamine ("Jeffamine" (registered trademark) T-403 (manufactured by Huntsman)) 4.0 wt%
<Pretreatment liquid-10>
(1) 95.0% by weight of triethylene glycol
(2) Polyoxyalkylene triamine ("Jeffamine" (registered trademark) T-403 (manufactured by Huntsman)) 5.0 wt%
<Pretreatment liquid-11>
(1) 95.0% by weight of triethylene glycol
(2) Polyoxyalkylenediamine ("Jeffamine" (registered trademark) D-230 (manufactured by Huntsman)) 5.0 wt%

(Comparative Examples 1-3)
Ink fillability and printing were carried out in the same manner as in Example 1 except that <Pretreatment liquid-12> to <Pretreatment liquid-14> having the following composition were used in the pretreatment tank of the automatic processor. When evaluation of non-image area peeling was performed, a decrease in ink adhesion was observed, but non-image area peeling did not occur. The evaluation results are shown in Table 1.
<Pretreatment liquid-12>
(1) 94.0% by weight of triethylene glycol
(2) Polyoxyalkylene triamine ("Jeffamine" (registered trademark) T-403 (manufactured by Huntsman)) 6.0 wt%
<Pretreatment liquid-13>
(1) 90.0% by weight of triethylene glycol
(2) Polyoxyalkylene triamine ("Jeffamine" (registered trademark) T-403 (manufactured by Huntsman)) 10.0 wt%
<Pretreatment liquid-14>
(1) Triethylene glycol 85.0% by weight
(2) Polyoxyalkylene triamine ("Jeffamine" (registered trademark) T-403 (manufactured by Huntsman)) 15.0 wt%

(Comparative Example 4)
Ink was prepared and printed in the same manner as in Comparative Example 3 except that a post-treatment liquid PA-1 (manufactured by Toray Industries, Inc.) containing 15% by weight of an organic solvent was used in a post-treatment tank of an automatic processor. When evaluation of flaking property and non-image area peeling was performed, good ink flaking property was exhibited and non-image line peeling did not occur.

  From this result, when the post-treatment liquid containing the organic solvent is not used in the post-treatment tank, pre-treatment is performed with the pre-treatment liquid containing 95% by weight or more of the ethylene glycol derivative represented by the general formula (I). As a result, it can be seen that the ink deposition property is improved.

Claims (3)

A method for developing a waterless lithographic printing plate having at least a photosensitive layer or a heat-sensitive layer and a silicone rubber layer on a substrate, wherein (1) the waterless lithographic printing plate is represented by the following general formula (I): A step of pretreatment with a pretreatment liquid containing 95% by weight or more of a glycol derivative, and (2) a step of developing the waterless lithographic printing plate after pretreatment with a developer containing water, and containing an organic solvent A method for developing a waterless lithographic printing plate, comprising no post-treatment step with a treatment liquid.
R— (OCH ₂ CH ₂ ) _n —OH (I)
(In the general formula (I), R represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. N represents an integer of 1 to 5) The pretreatment liquid contains 95% by weight or more of the ethylene glycol derivative represented by the general formula (I) and 5% by weight or less of an amine compound having two or more primary amino groups in one molecule. The developing method according to claim 1. The method for developing a waterless lithographic printing plate according to claim 1, wherein the silicone rubber layer of the waterless lithographic printing plate contains a colored pigment.