Plate making device and plate making method

Abstract

To provide a plate-making device and a plate-making method by which a printing plate can be reused, and when performing printing with a printing plate in which a new pattern is written, a good printed image without fog of the previous image can be obtained.SOLUTION: A plate-making device for forming a pattern on a printing plate for ink film formation having a surface layer, which contains a stimulus responsive compound of which physical property reversibly changes in response to external stimulus, has: a first stimulation applying part which applies first stimulation, that changes physical property of a surface of the printing plate from first physical property to second physical property on the basis of image data, to the surface, thereby forming a pattern; a second stimulation applying part which applies second stimulation, that changes physical property of the surface of the printing plate from second physical property to first physical property, to the surface, thereby deleting the pattern; and a cleaning part which removes an ink remaining on the surface of the printing plate.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a plate making apparatus and a plate making method. [Background technology]

[0002] There are two typical methods for lithographic printing. One is a method in which hydrophilic and hydrophobic areas are provided on the surface of a lithographic plate, the hydrophilic areas are wetted with water by immersing the plate in water in advance, and a liquid film structure having ink only in the hydrophobic areas is formed by applying a water-immiscible ink to the surface of the lithographic plate, which is then transferred to perform printing. The other is a method in which a lithographic plate having a photosensitive layer and a silicone rubber layer laminated in order is partially exposed to light and developed to remove a part of the photosensitive layer together with the silicone rubber layer, or only the silicone rubber layer. This is a waterless lithographic printing method in which printing is performed using a lithographic plate having a pattern formed thereon, without using water, and having a non-image area where the silicone rubber layer is the surface and an image area where at least the silicone rubber layer has been removed.

[0003] In lithographic printing, the printing plate surface does not appear to have a convex or concave shape at first glance, but for example, in waterless lithographic printing, there is a step between the image area and the non-image area formed on the lithographic plate, which is at least equal to the thickness of the silicone rubber layer, and strictly speaking, it cannot be said to be flat. In addition, since the lithographic plate is formed through the processes of coating, exposure, and development, the number of steps is long and it cannot be formed in a simple process. Furthermore, as can be seen from the manufacturing process, the pattern on the lithographic plate cannot be easily rewritten.

[0004] That is, in the case of conventional lithographic printing (analog printing), it is not easy to change a lithographic plate once a print pattern has been formed, and a new lithographic plate must be made from scratch every time a different printed matter is to be printed, resulting in problems such as lost time and increased costs each time a lithographic plate is made.In addition, there is a disadvantage from an environmental perspective in that the old plate must be discarded every time a new plate is made.

[0005] In order to overcome such disadvantages, a technique for rewriting a printing plate by two stimuli has been proposed. For example, in Patent Document 1, a polymer layer capable of forming and erasing a pattern is used as a printing plate. In the technique described in Patent Document 1, a pattern is formed by photocatalytic and / or photochemical treatment of the polymer layer. Meanwhile, the pattern formed in the polymer layer is made erasable by the action of an electromagnetic beam and / or the action of heat and / or the action of at least one solvent and / or removal by polishing. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2007-98945 A Summary of the Invention [Problem to be solved by the invention]

[0007] The technology described in Patent Document 1 makes it possible to erase a pattern on a printing plate by an external stimulus such as the action of an electromagnetic beam and / or the action of heat and / or the action of at least one solvent and / or removal by polishing.

[0008] However, in the technology described in Patent Document 1, an external stimulus is applied to erase or rewrite a pattern while ink remains on the printing plate. As a result, the remaining ink interferes with the external stimulus, resulting in some areas where the pattern cannot be erased or rewritten. As a result, even if printing is performed with a printing plate on which a new pattern has been written, the pattern from the previous printing plate is printed, and it has been found that problems such as the image of the new printing plate overlapping the image of the previous printing plate (hereinafter also referred to as the "previous image") (referred to as fogging) occur.

[0009] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a plate-making apparatus and method which allows the printing plates to be reused and, when a new pattern is written on a printing plate, produces a good printed image free of fog from the previous image. [Means for solving the problem]

[0010] The present inventors have conducted extensive research and have found that the above-mentioned problems can be solved by a platemaking apparatus that includes a first stimulus applying section for writing a pattern on a printing plate and a second stimulus applying section for erasing the pattern, as well as a cleaning section for removing ink remaining on the printing plate after printing, for a printing plate having a surface layer containing a stimulus-responsive compound whose surface properties change reversibly in response to an external stimulus, and have thus completed the present invention.

[0011] In other words, the present invention is a platemaking apparatus for forming a pattern on an ink film forming plate having a surface layer containing a stimulus-responsive compound whose physical properties change reversibly in response to an external stimulus, the platemaking apparatus having a first stimulus application section that applies a first stimulus to the surface of the printing plate, which changes the physical properties of the surface from a first physical property to a second physical property based on image data, thereby forming a pattern, a second stimulus application section that applies a second stimulus to the surface of the printing plate, which changes the physical properties of the surface from the second physical property to the first physical property, thereby erasing the pattern, and a cleaning section that removes ink remaining on the surface of the printing plate. Effect of the Invention

[0012] In the plate-making apparatus of the present invention, a pattern is written and erased by two external stimuli, a first stimulus and a second stimulus, on a printing plate having a surface layer containing a stimuli-responsive compound whose surface properties change reversibly in response to an external stimulus, so that the printing plate can be used repeatedly. In addition, by removing ink remaining on the surface of the printing plate using a cleaning member, image defects caused by the remaining ink can be suppressed. In addition, the remaining ink is prevented from inhibiting the change in the surface properties caused by the external stimulus. Therefore, the surface properties are reliably changed, and fogging of the previous image can be suppressed. [Brief description of the drawings]

[0013] [Figure 1]1 is a schematic diagram showing a plate making apparatus according to an embodiment of the present invention; [Diagram 2] 1 is a schematic diagram showing a plate making apparatus according to an embodiment of the present invention; [Diagram 3] 1 is a schematic diagram showing a plate making apparatus according to an embodiment of the present invention; [Figure 4] 1 is a schematic diagram showing a plate making apparatus according to an embodiment of the present invention; [Diagram 5] 1 is a schematic diagram showing a plate making apparatus according to an embodiment of the present invention; [Figure 6] 1 is a schematic diagram showing a plate making apparatus according to an embodiment of the present invention; [Figure 7] 1 is a perspective view showing a main part of a printing device according to an embodiment of the present invention; [Figure 8] 1 is a schematic diagram showing a plate making apparatus according to an embodiment of the present invention; [Figure 9] FIG. 1 is a schematic diagram showing a plate making apparatus according to a comparative example. [Figure 10] FIG. 2 is a diagram showing an image pattern on the printing plate surface in the initial printing used for evaluation. [Figure 11] FIG. 1 shows the image pattern of the rewritten printing plate surface used for evaluation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The present invention is a platemaking apparatus for forming a pattern on an ink film-forming printing plate having a surface layer containing a stimulus-responsive compound whose physical properties change reversibly in response to an external stimulus, the platemaking apparatus comprising: a first stimulus applying section for applying a first stimulus to the surface of the printing plate to change the physical properties of the surface from a first physical property to a second physical property based on image data to form a pattern; a second stimulus applying section for applying a second stimulus to the surface of the printing plate to change the physical properties of the surface from the second physical property to the first physical property to erase the pattern; and a cleaning section for removing ink remaining on the surface of the printing plate. With the platemaking apparatus having such a configuration, the printing plate can be reused, and when printing is performed with a printing plate on which a new pattern has been written, a good printed image without fog of the previous image can be obtained.

[0015] Although the details of why the plate-making apparatus of the present invention provides the above-mentioned effects are unclear, the following mechanism is thought to be the cause. Note that the following mechanism is based on speculation, and the present invention is not limited to the following mechanism in any way.

[0016] In the technology described in the above-mentioned Patent Document 1, while ink remains on the printing plate, an external stimulus (second stimulus) such as the action of an electromagnetic beam and / or heat and / or the action of at least one solvent and / or removal by polishing is applied to erase the pattern. If ink remains on the printing plate surface, when the pattern is erased by the second stimulus, or when the pattern is rewritten by an external stimulus (first stimulus) such as photocatalytic treatment and / or photochemical treatment, the remaining ink may inhibit changes in the surface physical properties caused by these external stimuli. This is thought to result in insufficient pattern erasure or insufficient rewriting, causing fogging of the previous image.

[0017] In response to this, the plate making apparatus of the present invention includes a first stimulus applying section that applies a first stimulus to change the physical properties of the surface of the printing plate from a first physical property to a second physical property to form a pattern on the surface of the printing plate, and a second stimulus applying section that applies a second stimulus to change the physical properties of the surface from the second physical property to the first physical property to erase the pattern, as well as a cleaning section that removes ink remaining on the surface of the printing plate. The ink remaining on the surface of the printing plate is sufficiently removed by the cleaning section, so that it is possible to prevent the pattern of the previous image from being printed by the remaining ink, and to prevent ink from easily running on the remaining ink to cause fogging. In addition, because the change in the physical properties of the surface due to the external stimulus occurs reliably, fogging of the previous image when printed with a rewritten printing plate can be further suppressed.

[0018] In addition, the plate-making apparatus of the present invention does not require the use of solvents or processing liquids when forming and erasing image patterns, and therefore does not produce waste liquids, thereby reducing the environmental impact.

[0019] The configuration of the plate making apparatus of the present invention will now be described.

[0020] In this specification, the range "X to Y" means "X or more and Y or less." Furthermore, unless otherwise specified, operations and measurements of physical properties are performed under conditions of room temperature (20 to 25°C) and relative humidity of 40 to 50% RH in this specification.

[0021] [Ink film forming plate] The platemaking apparatus of the present invention is a platemaking apparatus for forming a repeatedly writable pattern on an ink film forming printing plate, the ink film forming printing plate having a surface layer containing a stimulus-responsive compound whose physical properties change reversibly in response to an external stimulus.

[0022] [Printing plate composition] The printing plate for forming an ink film (also called a printing plate) used in the plate making apparatus of the present invention preferably comprises a support and a surface layer containing a stimuli-responsive compound and a resin disposed on the support.

[0023] (Support) The shape of the support is not particularly limited, and examples thereof include a flat plate shape, a cylindrical shape, and the like.

[0024] The material of the support is not particularly limited, and examples thereof include metals such as aluminum, aluminum alloys (such as alloys of aluminum and magnesium and / or silicon), iron, and stainless steel, and plastics such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyacrylonitrile, polyvinyl chloride, epoxy resins, phenolic resins, and styrene-butadiene rubber. These may be used alone or in combination of two or more.

[0025] The support may have either a single layer or a multilayer structure. If the support has a multilayer structure, each layer may be made of a different material.

[0026] (Surface layer) <Resin> The surface layer may contain a resin. The resin contained in the surface layer is not particularly limited, and either a thermoplastic resin or a thermosetting resin can be used.

[0027] Examples of thermoplastic resins include polyolefin resins such as polyethylene and polypropylene, cyclic polyolefin resins, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polyvinyl chloride resin, polyvinylidene chloride resin, polytetrafluoroethylene resin, polystyrene resin, polyether resin, polyvinyl acetate resin, acrylonitrile-butadiene-styrene (ABS) resin, acrylonitrile-styrene (AS) resin, acrylic resin, styrene acrylic resin, polyamide resin, polyacetal resin, polycarbonate resin, modified polyphenylene ether resin, polybutylene terephthalate resin, polyethylene terephthalate resin, polyphenylene sulfide resin, polysulfone resin, polyethersulfone resin, amorphous polyarylate resin, liquid crystal polymer, polyetheretherketone resin, thermoplastic polyimide resin, polyamideimide resin, and copolymers thereof.

[0028] Examples of thermosetting resins include solid epoxy resins, silicone resins, silicone-modified resins, formaldehyde resins, phenolic resins, melamine resins, urea resins, benzoguanamine resins, unsaturated polyester resins, alkyd resins, diallyl phthalate resins, polyurethane resins, thermosetting polyimide resins, crosslinked acrylic resins (for example, crosslinked polymethyl methacrylate resins), crosslinked polystyrene resins, and polyamic acid resins (resins that are imidized by heating to form a polyimide structure).

[0029] The above resins may be used alone or in combination of two or more. In addition, a hybrid resin formed by bonding two or more polymerized segments (resin segments), such as a resin having a vinyl polymerized segment (vinyl resin segment) and a polyester polymerized segment (polyester resin segment), may be used.

[0030] Among these, from the viewpoint of the ease with which the affinity of the stimuli-responsive compound with water is changed, thermoplastic resins are preferred, and styrene-acrylic resins, polycarbonate resins, polyethylene terephthalate resins, and polyolefin resins are more preferred.

[0031] The resin contained in the surface layer may be a synthetic product or a commercially available product. Examples of commercially available resin products include VS-1063 (weight average molecular weight: 5,500), US-1071 (weight average molecular weight: 10,000), X-1 (weight average molecular weight: 18,000), YS-1274 (weight average molecular weight: 19,000), VS-1047 (weight average molecular weight: 10,000), and RS-1191 (weight average molecular weight: 6,500), all of which are manufactured by Seiko PMC Corporation.

[0032] The weight average molecular weight of the resin contained in the surface layer is not particularly limited, but is preferably from 5,000 to 30,000, and more preferably from 8,000 to 20,000.

[0033] The content of the resin in the surface layer is preferably 30 to 80% by mass, more preferably 40 to 70% by mass, based on the total mass of the stimuli-responsive compound and resin contained in the surface layer. Within this range, the strength of the surface layer can be improved while maintaining fast stimuli responsiveness.

[0034] In this specification, the weight average molecular weight is a value measured by gel permeation chromatography (GPC).

[0035] <Stimulus-responsive compounds> A stimuli-responsive compound refers to a compound that reversibly changes its properties in response to an external stimulus. In the present invention, a stimuli-responsive compound is used whose surface properties change reversibly in response to two external stimuli, a first stimulus and a second stimulus, that is, whose surface properties change from the first property to the second property in response to the first stimulus, and whose surface properties change from the second property to the first property in response to the second stimulus. Preferably, a stimuli-responsive compound whose affinity for water changes reversibly in response to an external stimulus is used.

[0036] In addition, the expression "the affinity for water changes reversibly in response to an external stimulus" means that a compound that has been given an external stimulus reversibly changes between hydrophilicity and hydrophobicity in response to the external stimulus.

[0037] Here, "reversibly changing between hydrophilicity and hydrophobicity" specifically means that the state of existence of a molecule changes in response to an external stimulus, and the hydrophilicity and hydrophobicity change. The state of existence of a molecule refers to the molecular structure and the molecular aggregation state. For example, in the case of a photoresponsive compound, the molecular structure changes in response to light, so that the hydrophilicity and hydrophobicity can be controlled by whether or not the hydroxyl group is oriented to the surface, and in the case of a temperature-responsive compound, the molecular aggregation state changes in response to temperature, so that the hydrophilicity and hydrophobicity can be controlled.

[0038] As described above, in the present invention, it is preferable to use a stimuli-responsive compound whose affinity for water changes reversibly in response to an external stimulus. It is also preferable that the physical properties of the surface of the printing plate change from hydrophobic to hydrophilic in response to a first stimulus, and from hydrophilic to hydrophobic in response to a second stimulus. Alternatively, it is preferable that the physical properties of the surface of the printing plate change from hydrophilic to hydrophobic in response to a first stimulus, and from hydrophobic to hydrophilic in response to the second stimulus. The change in hydrophilicity and hydrophobicity allows high control of the ink according to the image pattern, and allows for the production of high-quality images.

[0039] The external stimulus is not particularly limited, but examples thereof include light, temperature change, pressure, electric field, and pH.

[0040] Examples of stimuli-responsive compounds include light-responsive compounds whose affinity for water reversibly changes in response to light, temperature-responsive compounds whose affinity for water reversibly changes in response to temperature changes, electric field-responsive compounds whose affinity for water reversibly changes in response to an electric field, and pH-responsive compounds whose affinity for water reversibly changes in response to pH.

[0041] The stimuli-responsive compound may be a synthetic product or a commercially available product. The stimuli-responsive compound may be used alone or in combination of two or more. Among them, a light-responsive compound or a temperature-responsive compound is preferred from the viewpoint of a fast rate of change in affinity with water.

[0042] Therefore, in a preferred embodiment of the present invention, the first and second external stimuli are lights having different wavelengths, and the stimulus-responsive compound is a photoresponsive compound. In another preferred embodiment, the first and second external stimuli are temperature changes having different wavelengths, and the stimulus-responsive compound is a temperature-responsive compound.

[0043] Preferred stimuli-responsive compounds, ie, light-responsive compounds and temperature-responsive compounds, will be described below.

[0044] <Photoresponsive compounds> The photoresponsive compound used in the present invention is preferably a compound that undergoes stereoisomerization or structural isomerization (cis-trans isomerization, photo-ring-opening reaction, etc.) upon irradiation with light, and that reversibly changes its affinity for water. Specific examples of such compounds include compounds having an azobenzene structure containing a hydrophilic group, compounds having a spiropyran structure containing a hydrophilic group, compounds having a stilbene structure containing a hydrophilic group, and compounds having a diarylethene structure containing a hydrophilic group. These compounds may be in the form of a polymer or a crosslinked product of the polymer.

[0045] Among these, compounds having an azobenzene structure containing a hydrophilic group, which undergoes cis-trans isomerization upon irradiation with light, or compounds having a stilbene structure containing a hydrophilic group are preferred from the viewpoint of the rapid rate of change in affinity with water.

[0046] Examples of hydrophilic groups include hydroxyl groups, carboxyl groups, mercapto groups, sulfonic acid groups, sulfate groups, phosphate groups, amino groups, etc. These hydrophilic groups may be used alone or in combination of two or more. Among them, the hydrophilic group is preferably a hydroxyl group from the viewpoint of a fast rate of change in affinity with water.

[0047] Specifically, the compound having an azobenzene structure containing a hydrophilic group is preferably a compound represented by the following chemical formula (1).

[0048] [ka]

[0049] In the above chemical formula (1), R 1 and R 2 are each independently a hydrophilic group, R 3 and R 4 each independently represents an alkyl group or an alkoxy group having 1 to 18 carbon atoms, and m1 and m2 each independently represent an integer of 0 to 4, with the proviso that m1+m2 is an integer of 1 to 8.

[0050] R in the above chemical formula (1) 1 and R 2 are each independently a hydrophilic group. Examples of the hydrophilic group are as described above. When m1+m2 is an integer of 2 to 8, the multiple hydrophilic groups may be the same or different.

[0051] R in the above chemical formula (1) 3 and R 4 are each independently an alkyl group having 1 to 18 carbon atoms or an alkoxy group having 1 to 18 carbon atoms.

[0052] Examples of the alkyl group having 1 to 18 carbon atoms include linear alkyl groups such as methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, and n-hexadecyl group; isopropyl group, isobutyl group, sec-butyl group, t-butyl group, isoamyl group, t-pentyl group, and the like. branched alkyl groups such as a butyl group, a neopentyl group, a 1-methylpentyl group, a 4-methyl-2-pentyl group, a 3,3-dimethylbutyl group, a 2-ethylbutyl group, a 1-methylhexyl group, a t-octyl group, a 1-methylheptyl group, a 2-ethylhexyl group, a 2-propylpentyl group, a 2,2-dimethylheptyl group, a 2,6-dimethyl-4-heptyl group, a 3,5,5-trimethylhexyl group, a 1-methyldecyl group, and a 1-hexylheptyl group;

[0053] Examples of alkoxy groups having 1 to 18 carbon atoms include linear alkoxy groups such as a methoxy group, an ethoxy group, an n-propoxy group, an n-butoxy group, an n-pentyloxy group, an n-hexyloxy group, an n-heptyloxy group, an n-octyloxy group, an n-nonyloxy group, an n-decyloxy group, an n-undecyloxy group, an n-dodecyloxy group, an n-tridecyloxy group, an n-tetradecyloxy group, an n-pentadecyloxy group, and an n-hexadecyloxy group; an isopropoxy group, a t-butoxy group, a 1-methylpentyloxy group, and the like. branched alkoxy groups such as a 4-methyl-2-pentyloxy group, a 3,3-dimethylbutyloxy group, a 2-ethylbutyloxy group, a 1-methylhexyloxy group, a t-octyloxy group, a 1-methylheptyloxy group, a 2-ethylhexyloxy group, a 2-propylpentyloxy group, a 2,2-dimethylheptyloxy group, a 2,6-dimethyl-4-heptyloxy group, a 3,5,5-trimethylhexyloxy group, a 1-methyldecyloxy group, and a 1-hexylheptyloxy group; and the like.

[0054] More specific examples of the compound having an azobenzene structure containing a hydrophilic group preferably include compounds represented by the following chemical formulas (2) to (3).

[0055] [ka]

[0056] [ka]

[0057] Specifically, the compound having a stilbene structure containing a hydrophilic group is preferably a compound represented by the following chemical formula (4).

[0058] [ka]

[0059] In the above chemical formula (4), R 5 ~R 10 are each independently a hydrogen atom, an alkoxy group having 1 to 6 carbon atoms, or a hydrophilic group, in which R 5 ~R 10 At least one of the groups is a hydrophilic group.

[0060] Examples of alkoxy groups having 1 to 6 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an isobutoxy group, a sec-butoxy group, a t-butoxy group, an n-pentyloxy group, an isopentyloxy group, a sec-pentyloxy group, a t-pentyloxy group, and an n-hexyloxy group.

[0061] Examples of the hydrophilic group are as described above.

[0062] A more specific example of the compound having a stilbene structure containing a hydrophilic group is preferably a compound represented by the following chemical formula (5) (isorhapontigenin, 3,4',5-trihydroxy-3'-methoxy-trans-stilbene).

[0063] [ka]

[0064] A preferred example of the photoresponsive compound in the form of a polymer is a polymer represented by the following chemical formula (6).

[0065] [ka]

[0066] In the above chemical formula (6), x is the number of repeating units and is not particularly limited as long as it is in the polymer region, but is in the range of 20 to 1,000, for example.

[0067] The above-mentioned photoresponsive compounds may be used alone or in combination of two or more. In addition, the above-mentioned photoresponsive compounds may be commercially available products or synthetic products.

[0068] Examples of methods for synthesizing a compound having an azobenzene structure containing a hydrophilic group include the following methods.

[0069] For example, a method for synthesizing the azobenzene compound represented by the above chemical formula (2) can be the method shown in the following reaction formula A. 2-Chloro-4-aminophenol is reacted with sodium nitrite under cooling to synthesize a diazonium salt, which is then reacted with 2-chlorophenol, and the resulting intermediate A is reacted with n-bromohexane to synthesize intermediate B. Next, the resulting intermediate B is reacted with an aqueous sodium hydroxide solution under high temperature and pressure, and treated with an acid to obtain the azobenzene compound represented by the above chemical formula (2) (azobenzene derivative (1)).

[0070] [ka]

[0071] For example, a method for synthesizing an azobenzene compound (azobenzene derivative (3)) represented by the above chemical formula (3) includes reacting intermediate B in the above reaction formula A with potassium amide in liquid ammonia (see reaction formula B below).

[0072] [ka]

[0073] For example, a method for synthesizing a polymer represented by the above chemical formula (6) can be the method shown in the following reaction formula C. In the same manner as in the above reaction formula A, a diazonium salt is synthesized, and reacted with 2-chlorophenol to obtain intermediate C, which is then reacted with n-bromohexanol to synthesize intermediate D. Next, intermediate D is reacted with acrylic acid chloride in the presence of triethylamine to obtain an acrylate monomer (intermediate E) containing an azobenzene structure, and the chloro group is converted to a hydroxy group to obtain intermediate F. The obtained intermediate F is subjected to a polymerization reaction using 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator to obtain an azobenzene compound (azobenzene derivative (polymer 2)) represented by the above chemical formula (6).

[0074] [ka]

[0075] <Temperature-responsive compounds> The temperature-responsive compound used in the present invention is preferably a compound whose affinity with water changes reversibly in response to a temperature change. The temperature-responsive compound preferably changes reversibly from hydrophobic (or hydrophilic) to hydrophilic (or hydrophobic) at the critical solution temperature (CST) for water. The temperature-responsive compound may be, for example: (1) A temperature-responsive compound that exhibits hydrophilicity at temperatures below its critical solution temperature (the critical solution temperature at this time is specifically referred to as the "lower critical solution temperature (LCST)"), but exhibits hydrophobicity at temperatures equal to or higher than the critical solution temperature. (2) A temperature-responsive compound that exhibits hydrophilicity at temperatures above its critical solution temperature (the critical solution temperature at this time is specifically referred to as the "upper critical solution temperature (UCST)"), but exhibits hydrophobicity at temperatures below that temperature. Any of the above can be used.

[0076] The temperature-responsive compound is not particularly limited, and examples thereof include acrylic polymers and methacrylic polymers. Specific examples include poly(Nn-propylacrylamide) (LCST: 21° C.), poly(Nn-propylmethacrylamide) (LCST: 27° C.), poly(N-isopropylacrylamide) (LCST: 32° C.), poly(N-isopropylmethacrylamide) (LCST: 43° C.), poly(N-ethoxyethylacrylamide) (LCST: about 35° C.), poly(N-tetrahydrofurfuryl acrylamide) (LCST: about 28° C.), and poly(N-tetrahydrofurfurylmethacrylamide) (LCST: about 35° C.). Examples of such polymers include polymers having structural units derived from N-substituted (meth)acrylamides such as poly(N-cyclopropylacrylamide) (LCST: 45°C), poly(N-acryloylpyrrolidine), poly(N-acryloylpiperidine), polymethyl vinyl ether, and copolymers thereof.

[0077] Other examples of the temperature-responsive compound include alkyl-substituted cellulose derivatives such as methyl cellulose, ethyl cellulose, and hydroxypropyl cellulose, and polyalkylene oxide block copolymers such as block copolymers of polypropylene oxide and polyethylene oxide.

[0078] Among these temperature-responsive compounds, polymers having structural units derived from N-substituted (meth)acrylamide are preferred from the viewpoints that their terminals can be easily modified to functional groups such as carboxylic acid groups, amine groups, and maleimide groups, or that pH responsiveness can be imparted by copolymerizing them with methacrylic acid.

[0079] These temperature-responsive compounds are not particularly limited, but can be obtained by polymerizing a monomer by irradiation or by solution polymerization.

[0080] The monomer may be one which exhibits temperature responsiveness when polymerized to obtain a homopolymer (hereinafter also referred to as "temperature responsive monomer"). The temperature responsive monomer is not particularly limited, but examples thereof include N-(or N,N-di)substituted (meth)acrylamide compounds, (meth)acrylamide compounds having a cyclic group, and vinyl ether compounds. The temperature responsive compound may be a homopolymer obtained by polymerizing one type of temperature responsive monomer, or a copolymer obtained by polymerizing two or more types of temperature responsive monomers. The copolymer may be any of a graft copolymer, a block copolymer, and a random copolymer.

[0081] Furthermore, the temperature-responsive compound may be a copolymer obtained by polymerizing, in addition to the above-mentioned temperature-responsive monomer, a monomer component that is not a temperature-responsive monomer itself within a range that does not inhibit temperature responsiveness, if necessary. The copolymer may be any of a random copolymer, a block copolymer, and a graft copolymer.

[0082] Furthermore, the temperature-responsive compound may be a crosslinked product of these polymers. When the temperature-responsive polymer is a crosslinked product, examples of such crosslinked products include N-alkyl(meth)acrylamides such as N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, Nn-propyl(meth)acrylamide, N-isopropyl(meth)acrylamide, Nn-butyl(meth)acrylamide, N-isobutyl(meth)acrylamide, and Nt-butyl(meth)acrylamide; N-vinyl alkylamides such as N-vinyl isopropylamide, N-vinyl-n-propylamide, N-vinyl-n-butylamide, N-vinyl isobutylamide, and N-vinyl-t-butylamide; vinyl alkyl ethers such as vinyl methyl ether and vinyl ethyl ether; alkylene oxides such as ethylene oxide and propylene oxide; and 2-alkyl-2-oxazolines such as 2-ethyl-2-oxazoline, 2-n-propyl-2-oxazoline, and 2-isopropyl-2-oxazoline, or polymers obtained by polymerizing two or more of these monomers in the presence of a crosslinking agent.

[0083] The crosslinking agent may be appropriately selected from conventionally known agents, and examples of crosslinking agents that can be suitably used include crosslinking monomers having a polymerizable functional group such as ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, N,N'-methylene bis(meth)acrylamide, tolylene diisocyanate, divinylbenzene, and polyethylene glycol di(meth)acrylate; glutaraldehyde; polyhydric alcohols; polyvalent amines; polyvalent carboxylic acids; and metal ions such as calcium ions and zinc ions. These crosslinking agents may be used alone or in combination of two or more.

[0084] The molecular weight of the temperature-responsive compound is not particularly limited, but it is preferable that the number average molecular weight measured by gel permeation chromatography (GPC) is 3,000 or more.

[0085] The temperature responsive compound may be used alone or in combination of two or more. In addition, the temperature responsive compound may be a commercially available product or may be synthesized as described above.

[0086] The content of the stimuli-responsive compound in the surface layer is preferably 20 to 70% by mass, and more preferably 30 to 60% by mass, based on 100% by mass of the total mass of the stimuli-responsive compound and resin contained in the surface layer. If the content is within this range, the strength of the surface layer can be improved and fast stimuli responsiveness can be maintained.

[0087] (Other Ingredients) The surface layer may further contain an antioxidant, a plasticizer, metal oxide particles, etc., within the scope not impairing the effects of the present invention. The thickness (dry thickness) of the surface layer is not particularly limited, but is preferably 3 to 30 μm, more preferably 5 to 10 μm.

[0088] (adhesive layer) The printing plate for forming an ink film may be one in which the surface layer is disposed on the support via an adhesive layer.

[0089] The adhesive used to form the adhesive layer (hereinafter also referred to as adhesive layer-forming adhesive) is not particularly limited, and is preferably a curable composition containing a curable resin and, if necessary, a polymerization initiator, a solvent, etc.

[0090] The curable resin may be an active energy ray (for example, ultraviolet light, visible light, X-ray, electron beam, etc.) curable type or a heat curable type, but is preferably an active energy ray curable type, and more preferably an ultraviolet ray curable type. The curable resin may be used alone or in combination of two or more kinds. In addition, the curable resin may be a commercially available product or a synthetic product.

[0091] As the ultraviolet curing resin, for example, ultraviolet curing urethane acrylate resin, ultraviolet curing polyester acrylate resin, ultraviolet curing epoxy acrylate resin, ultraviolet curing polyol acrylate resin, ultraviolet curing epoxy resin, etc. are preferably used. Among them, ultraviolet curing urethane acrylate resin and ultraviolet curing polyol acrylate resin are preferable.

[0092] Examples of the ultraviolet-curable polyol acrylate resin include ethylene glycol (meth)acrylate, polyethylene glycol di(meth)acrylate, glycerin tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and alkyl-modified dipentaerythritol penta(meth)acrylate. Examples of the ultraviolet-curable polyol acrylate resin include commercially available products such as Sartomer (registered trademark) SR295, 350, and 399 (manufactured by Sartomer).

[0093] The polymerization initiator can be appropriately selected from known photopolymerization initiators, thermal polymerization initiators, etc. depending on the type of curable resin used. The adhesive for forming the adhesive layer may be either a commercially available product or a synthetic product.

[0094] When the adhesive is cured by irradiating it with active energy rays, the irradiation conditions (type of light source, irradiation intensity, irradiation time, etc.) can be appropriately selected. As the light source, a known light source such as a low pressure mercury lamp, a high pressure mercury lamp, a xenon lamp, or a metal halide lamp can be used. The irradiation intensity is not particularly limited, but is, for example, 10 to 200 mW / cm. 2 The irradiation time is not particularly limited, but is, for example, 1 to 10 minutes. When the adhesive is cured by heating, the heating temperature and heating time can be appropriately adjusted.

[0095] The thickness (dry thickness) of the adhesive layer is not particularly limited, but is preferably 0.5 to 3 μm.

[0096] [Method of manufacturing a printing plate for forming an ink film] The method for manufacturing a printing plate for forming an ink film is not particularly limited, but examples include a method in which a solution for forming a surface layer containing a stimuli-responsive compound and a resin is prepared, and then the solution is applied onto a support and dried to provide a surface layer.

[0097] The solvent used in the surface layer forming solution is not particularly limited, and examples thereof include aliphatic solvents such as n-pentane, n-hexane, n-heptane, n-octane, cyclohexane, and methylcyclohexane; ketone solvents such as methyl ethyl ketone, acetone, and cyclohexanone; ether solvents such as diethyl ether, isopropyl ether, tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether, anisole, and phenetole; and ethyl acetate. Examples of suitable solvents include ester-based solvents such as butyl acetate and ethylene glycol diacetate; aromatic solvents such as toluene and xylene; cellosolve-based solvents such as methyl cellosolve, ethyl cellosolve and butyl cellosolve; alcohol-based solvents such as methanol, ethanol, propanol and isopropyl alcohol; ether-based solvents such as tetrahydrofuran and dioxane; halogen-based solvents such as dichloromethane and chloroform; nitrile-based solvents such as acetonitrile and propionitrile; and polar solvents such as N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N,N-dimethylformamide and N,N-dimethylacetamide. These solvents can be used alone or in combination of two or more.

[0098] The total content of the resin and the stimuli-responsive compound in the surface layer forming solution is not particularly limited, but is preferably 30 to 60% by mass.

[0099] Methods for applying the surface layer onto the support include, for example, a spin coating method; a dipping method; a dripping method; and a method using a liquid film coating device such as a roll coater, a rod coater, a curtain coater, a slide coater, a doctor knife, a screen coater, a slot coater, an extrusion coater, a blade coater, a gravure coater, or an inkjet coater.

[0100] After the coating liquid is applied, the plate is air-dried as necessary, and then dried using a vacuum dryer or the like to obtain a printing plate for forming an ink film. When using a vacuum dryer, the drying temperature is not particularly limited, but is preferably 25 to 40° C. The drying time is also not particularly limited, but is preferably 1 to 4 hours.

[0101] When manufacturing a printing plate having an adhesive layer between the support and the surface layer, an adhesive layer can be provided on the support by the method described above in the [Adhesive Layer] section, and then the surface layer can be formed on the adhesive layer.

[0102] [Plate making equipment] Fig. 1 is a schematic diagram showing a plate-making apparatus A-1 according to one embodiment of the present invention. The plate-making apparatus A-1 is a plate-making apparatus for forming a repeatedly writable pattern on an ink film forming printing plate 12. The plate-making apparatus A-1 having the configuration shown in Fig. 1 has a first stimulus applying section 1, a second stimulus applying section 2, and a cleaning section 3, and the printing plate 12 passes on a conveyor belt 11 in the direction of the arrow in the order of the cleaning section 3, the second stimulus applying section 2, and the first stimulus applying section 1.

[0103] (First Stimulus Applicator) In a plate-making apparatus according to one embodiment of the present invention, a first stimulus (solid arrow in FIG. 1) is applied to the surface layer of a printing plate 12 from a first stimulus application unit 1. The first stimulus changes the physical property of the surface of the printing plate 12 from a first physical property to a second physical property. The first stimulus application unit 1 changes the physical property of the surface of the printing plate 12 by the first stimulus, thereby drawing a pattern on the printing plate 12 consisting of printing areas and non-printing areas. The pattern on the printing plate 12 is drawn, for example, based on image data to be printed. For example, a pattern consisting of hydrophilic areas and hydrophobic areas is formed.

[0104] When the surface layer of the printing plate 12 contains a photoresponsive compound, the first stimulus applying unit 1 serving as the writing means may be a known light source such as a light emitting diode (LED) or a monochromatic laser light source. When the surface layer of the printing plate 12 contains a temperature responsive compound, the first stimulus applying unit 1 serving as the writing means may be an infrared lamp or a monochromatic laser light source. These may be installed alone or in combination of two or more.

[0105] By partially applying an external stimulus to the ink film forming printing plate 12 from the first stimulus applying unit 1, a pattern consisting of a portion with a first physical property and a portion with a second physical property is formed on the surface layer of the printing plate 12. In this specification, "partially applying an external stimulus" refers to applying an external stimulus to either the image portion or the non-image portion of the image pattern to be written.

[0106] As described above, the stimulus responsive compound is preferably a light responsive compound or a temperature responsive compound. Therefore, the external stimulus applied by the first stimulus application unit 1 is preferably light or a temperature change.

[0107] When the surface layer of the printing plate 12 contains a photoresponsive compound, the external stimulus is light. In this case, the wavelength region of the light irradiated from the writing means (preferably a monochromatic laser light source) is not particularly limited. For example, when the compound of the above chemical formula (1) is used, photoisomerization from a trans form to a cis form occurs by irradiating light of 200 to 400 nm, and the physical properties of the surface change from hydrophobic to hydrophilic. In this case, when the non-image portion is irradiated with light, the non-image portion becomes hydrophilic. Then, the image portion, which is not irradiated with light, becomes hydrophobic, and printing can be performed using hydrophobic ink. The wavelength of the light is more preferably 280 to 400 nm. With such a wavelength region, light can be irradiated to a finer region, and small characters and fine images can be reproduced more clearly. In addition, since the energy received by the surface layer is not too large, the surface layer is less likely to deteriorate and can withstand repeated rewriting operations.

[0108] Furthermore, for example, when the compound of the above chemical formula (1) is used, photoisomerization from cis to trans isomers occurs by irradiation with visible light (preferably visible light in the wavelength range of 400 to 600 nm), and the physical properties of the surface change from hydrophilic to hydrophobic. In this case, when the image portion is irradiated with light, the image portion becomes hydrophobic, and printing can be performed using hydrophobic ink. When the printing plate is unused, it is preferable to apply a second stimulus to the entire surface of the printing plate 12 in advance, for example, by a second stimulus portion described later, to make the physical properties of the surface hydrophilic.

[0109] The amount of light irradiated by the first stimulus is, for example, 1 to 30 J / cm 2 Within this range, small characters and fine images can be written clearly, and writing can be performed without placing too much strain on the surface layer.

[0110] When the surface layer of the printing plate 12 contains a temperature-responsive compound, the external stimulus is a temperature change. The above-mentioned temperature-responsive compound has a critical dissolution temperature, so a temperature change is applied to the surface layer so as to pass through this critical dissolution temperature, and a pattern consisting of hydrophilic and hydrophobic regions is formed on the surface layer of the printing plate 1. In this case, the first stimulus applying unit 1, which is the writing means used, is preferably a monochromatic laser light source that emits light with a wavelength of 700 to 900 nm. Partial heating is performed by this writing means to form a pattern.

[0111] When various light sources are used as the first stimulus applying unit 1, it is preferable to irradiate the surface of the printing plate 12 with light from the light source as fine dots (pin spots) or fine lines so that only the stimulus-responsive compound to which an external stimulus has been applied changes its affinity for water. The pin spots can be formed by various methods, such as an irradiation method in which light from a light source is guided by an optical fiber and irradiated, and a lens reduction method in which a plurality of light sources are arranged in the traveling direction of the printing plate 12, reduced by a lens, and irradiated in the traveling direction of the printing plate 12. In addition, fine lines can also be formed by, for example, scanning with a laser beam. Furthermore, it is also possible to adopt an irradiation method by projecting an image pattern, etc., as long as it can supply the required amount of light. It is preferable that the size of the light dots and the thickness of the lines on the surface of the printing plate 12 are the same as the size of the dots (dots) that constitute the image area in general offset printing. The image pattern is formed on the entire printing plate 12 by irradiating light while moving the printing plate 12.

[0112] The first stimulus applying unit 1, which is the writing means, only needs to be reactivated when printing a different printed matter by changing at least the image pattern, and does not need to be used again when printing multiple copies of the same printed matter. In other words, the image pattern formed on the surface layer by one writing is maintained as it is. Therefore, by placing the printing plate on which the image pattern has been written in, for example, in a printing device, and continuously transferring the ink film by the transfer means of the printing device, multiple copies can be printed without rewriting.

[0113] Therefore, for example, when writing on a new printing plate for the first time, in the printing apparatus A-1, a printing plate can be prepared by applying only the first stimulus by the first stimulus applying unit 1, without cleaning by the cleaning unit 3 or applying the second stimulus by the second stimulus applying unit 2. This can then be placed in the printing apparatus as described above, and printing can be performed.

[0114] (Second Stimulus Applicator) The second stimulus application unit 2 applies a second stimulus (dotted arrow in FIG. 1 ) to the surface of the printing plate 12, which changes the physical properties of the surface of the printing plate 12 from the second physical properties to the first physical properties. In this case, the printing plate 12 may be a printing plate on whose surface a pattern has been formed by the above-mentioned first stimulus application unit 1. The second stimulus application unit 2 changes the portion that had the second physical properties to the first physical properties by the second stimulus. The second stimulus application unit erases the pattern consisting of the printing area and the non-printing area from the surface of the printing plate 12 by changing the physical properties of the surface of the printing plate 12 by the second stimulus.

[0115] When the surface layer of the printing plate 12 contains a photoresponsive compound, the second stimulus applying unit 2, which is the erasing means, may be a known light source such as a light emitting diode (LED) or a monochromatic laser light source. Light from the light source is irradiated onto the surface of the printing plate 12 as diffused light or linear light in the traveling direction of the printing plate 12, for example, by a lens or the like. The light serving as the second stimulus is preferably uniform in the traveling direction of the printing plate 12, but some variation is acceptable as long as the light has an intensity sufficient to erase the pattern from the surface of the printing plate 12 as the second stimulus. The light serving as the second stimulus may also be irradiated by scanning a laser light in the traveling direction of the printing plate 12.

[0116] The wavelength region of the light as the second stimulus irradiated from the second stimulus applying unit 2 is not particularly limited. For example, when the compound of the above chemical formula (1) is used, from the viewpoint of the rate of change of affinity with water, when the wavelength of the light as the first stimulus from the first stimulus applying unit 1 is 200 to 400 nm, the wavelength of the light as the second stimulus from the second stimulus applying unit 2 is preferably 400 to 600 nm. Similarly, when the wavelength of the light as the first stimulus from the first stimulus applying unit 1 is 400 to 600 nm, the wavelength of the light as the second stimulus from the second stimulus applying unit 2 is preferably 200 to 400 nm, more preferably 280 to 400 nm.

[0117] The amount of light irradiated by the second stimulus is, for example, 1 to 30 J / cm 2 Within this range, the image pattern can be easily erased, and erasure can be performed without placing too much strain on the surface layer.

[0118] When the surface layer of the printing plate 12 contains a temperature responsive compound, examples of the second stimulus applying unit 2 include a cold air generator capable of generating cold air at 5 to 20°C, a thermostatic bath at 5 to 20°C, and the like.

[0119] The pattern is erased by the second stimulus applying unit 2 as the erasing means, and the surface layer of the printing plate 12 has the same properties as before the external stimulus was applied. Thereafter, a new pattern can be formed on the surface layer by performing the above-mentioned writing process again. In other words, the plate making apparatus of the present invention makes it easy to digitally rewrite a pattern.

[0120] (Cleaning Department) The plate making apparatus of the present embodiment has a cleaning unit 3 that removes ink remaining on the surface of the printing plate 12 after printing. Preferably, the cleaning unit 3 removes ink adhering to the surface of the printing plate 12 before the second stimulus applying unit 2 erases the pattern of the printing plate 12.

[0121] The cleaning unit 3 is not particularly limited as long as it can remove ink remaining on the printing plate used in printing. For example, an air knife or a means for sucking ink with air can be used, but in the plate making device of this embodiment, it is preferable that the device is provided with an abutting member that abuts against the printing plate 12, and that the ink remaining on the printing plate is adhered to the abutting member by pressing the printing plate with the abutting member, thereby removing the ink. In this way, the ink can be removed more effectively. It is preferable that the abutting member is capable of abutting against and separating from the surface of the printing plate 12. For example, when writing on a new printing plate for the first time, it is preferable that the abutting member is separated from the surface of the printing plate.

[0122] The contact member may be a cleaning roller, a cleaning belt, a cleaning blade, or the like, but it is preferable to use a cleaning roller 6 as in the plate making apparatus A-1 shown in Fig. 1, since it can collect the ink evenly. It is more preferable for the cleaning roller 6 to have a member containing a material having high surface adhesion on its surface, since it can efficiently adhere the ink. As materials having high surface adhesion, polyimide resin, nylon resin, polyester resin, polyurethane resin, and polycarbonate resin are preferable, and polyimide resin and nylon resin are particularly preferable.

[0123] When a cleaning blade 7 is used as the abutment member, as in the printing plate apparatus A-3 shown in Figure 2, it is preferable that the cleaning blade 7 is positioned so that the tip of the blade faces in the opposite direction (counter direction) to the traveling direction of the printing plate 12 when in contact with the surface of the printing plate 12.

[0124] The cleaning blade 7 may be, for example, a squeeze blade made of an elastic material such as polyurethane, silicone rubber, etc. These squeeze blades come into contact with the surface of the printing plate 12 and squeeze (scrape) the ink off to remove it.

[0125] In the case where a cleaning roller 6 is used as the contact member as in the plate making apparatus B-1 shown in FIG. 3, it is preferable that the cleaning unit 3 further includes an ink recovery unit 4 that recovers ink adhering to the cleaning roller 6. This makes it possible to more reliably remove ink adhering to the printing plate 12. The ink recovery unit 4 is preferably configured such that a member having high ink absorption (ink absorbent member) 8 is attached to a support member (not shown) made of, for example, metal or resin so as to contact the surface of the cleaning roller 6, and absorbs or wipes off the ink from the surface of the cleaning roller 6 to remove it. As the member having high ink absorption 8, a woven fabric, a nonwoven fabric, or a sponge can be preferably used. With this configuration, the ink adhering to the cleaning roller 6 can be sucked up by the member having high ink absorption 8, making it possible to more reliably remove the ink adhering to the printing plate 12.

[0126] 4, the ink recovery section 4 may include a pressure roller 9 in contact with the cleaning roller 6 and cleaning paper 10 passed between the cleaning roller 6 and the pressure roller 9, and recover the ink adhering to the cleaning roller 6 by transferring it to the cleaning paper 10. With this configuration, the ink adhering to the cleaning roller 6 can be removed by the cleaning paper 10, and the ink adhering to the printing plate 12 can be more reliably removed.

[0127] As in the plate-making apparatus C shown in Figure 5, it is preferable that the cleaning section 3 further has a third stimulus applying section 5 that applies an external stimulus (third stimulus) to at least one of the surface of the printing plate and the remaining ink at at least one of the stages before and simultaneously with the ink removal.

[0128] The third stimulus applied from the third stimulus application unit 5 is preferably one that changes the state of the surface of the printing plate 12 or the remaining ink. Specifically, it is preferable that the third stimulus changes the physical properties of the surface of the printing plate 12 or the physical properties of the ink so that the affinity between the surface and the ink is reduced. For example, by installing the third stimulus application unit 5 downstream of the cleaning roller 6 and applying the third stimulus to the surface of the printing plate 12 at a position where the cleaning roller abuts against the printing plate 12 or downstream of the position, the state of the surface of the printing plate 12 or the remaining ink can be changed before or at the same time as the third stimulus reaches the cleaning roller 6, thereby assisting in the removal of the ink.

[0129] A UV light source or a heat source can be installed as the third stimulus applying unit 5. This makes it possible to change the state of the remaining ink by curing, drying, or the like.

[0130] In addition, the third stimulus applying unit 5 can be a light source such as an LED light source, a heat source, or a means for applying electrical stimuli, which can change the surface condition of the printing plate 12 by changing the surface shape to reduce ink adhesion, or by changing the physical properties of the surface such as hydrophilicity or hydrophobicity.

[0131] In particular, since it can effectively assist in the removal of remaining ink, it is preferable that the external stimulus applied by the third stimulus application unit is the same type of stimulus as the first or second stimulus. Here, the same type of stimulus means, for example, that if the first or second stimulus is light, the third stimulus is also light, and if the first or second stimulus is heat (temperature change), the third stimulus is also heat, and means that it is light of a wavelength that can bring about a change in the physical properties of the surface of the printing plate (from the first physical property to the second physical property, or from the second physical property to the first physical property) like either the first or second stimulus, or a temperature change. For example, if the first or second stimulus is light, it is preferable that the third stimulus is light having a central wavelength of about ±50 nm of the central wavelength of either of the above lights. However, it is preferable that the light from the light source is irradiated onto the entire surface of the printing plate 12 as, for example, diffused light or linear light, and the amount of irradiation light is, for example, 0.1 to 30 J / cm. 2 For example, when the first or second stimulus is heat, the third stimulus is preferably heating at about ±15°C of any of the above heating temperatures. Preferably, the third stimulus is light using the same light source as either the first or second stimulus, or light of the same wavelength. Also, preferably, the third stimulus is the same temperature change as either the first or second stimulus.

[0132] (Rewrite of printing plate) When the printing plate 12 is new, no ink is supplied to the surface of the printing plate 12. Therefore, when the printing plate 12 is new, a desired pattern is written on the surface of the printing plate 12 by applying a first stimulus from the first stimulus applying unit 1 while moving the printing plate. As a result, a pattern is formed on the printing plate 12.

[0133] In the case of rewriting the printing plate 12, the printing plate 12 after printing is passed through the cleaning section 3, the second stimulus applying section 2, and the first stimulus applying section 1 of the plate-making apparatus A-1 in that order using a known transport means such as a transport belt 11, as shown in Figure 1, so that the ink remaining on the printing plate after printing can be removed by the cleaning section 3, the pattern can be erased by the second stimulus applying section 2, and the pattern can be rewritten by the first stimulus applying section 1, in that order.

[0134] Alternatively, as shown in Figure 6, the printed printing plate 12 can be passed through the second stimulus application section 2, the cleaning section 3, and the first stimulus application section 1 of the plate-making device D in that order, allowing the pattern to be erased by the second stimulus application section 2, the ink remaining on the printing plate to be removed by the cleaning section 3, and the pattern to be rewritten by the first stimulus application section 1, in that order.

[0135] However, in the plate making apparatus of this embodiment, it is preferable that the printing plate 12 passes through the cleaning section 3, the second stimulus applying section 2, and the first stimulus applying section 1 in this order. In this way, both the second stimulus and the first stimulus can be applied in a state in which the ink remaining on the printing plate after printing is reduced. Therefore, both the change in the surface state due to the second stimulus and the change in the surface state due to the first stimulus can be reliably performed. As a result, fogging of the previous image can be further reduced.

[0136] [Plate making method] The present invention also provides a platemaking method for forming a repetitively writable pattern on an ink film forming printing plate. That is, one embodiment of the present invention is a platemaking method comprising a first stimulus applying step of applying a first stimulus to the surface of an ink film forming printing plate having a surface layer containing a stimulus-responsive compound whose physical properties change reversibly in response to an external stimulus, the first stimulus changing the physical properties of the surface from a first physical property to a second physical property based on image data to form a pattern, a step of forming an ink film on either an image portion or a non-image portion of the printing plate on which the pattern is formed, a step of printing using the printing plate on which the ink film is formed, a second stimulus applying step of applying a second stimulus to the surface of the printing plate after printing, the second stimulus changing the physical properties of the surface from the second physical property to the first physical property to erase the pattern, a step of applying the first stimulus to the surface of the printing plate from which the pattern is erased to form a new image pattern, and a cleaning step of removing ink remaining on the surface of the printing plate after printing, either after the printing step and before the second stimulus applying step, or after the second stimulus applying step and before the step of forming the new image pattern.

[0137] The specific forms of the first stimulus applying step, the second stimulus applying step, and the cleaning step are as described above, and therefore will not be described here. The step of forming a new image pattern is the same as the first stimulus applying step, except that the first stimulus is applied to the printing plate from which the pattern has been erased after printing, based on new image data.

[0138] For the process of forming an ink film on either the image or non-image area of ​​the printing plate on which the pattern is formed, and then printing using the printing plate on which the ink film has been formed, any conventionally known means, such as a printing method using a general offset printing machine, can be appropriately adopted.

[0139] In the step of forming an ink film, ink is applied to the pattern formed in the first stimulus application step to form an ink film. The means for applying the ink is not particularly limited. In this specification, "forming an ink film" refers to the ink being held at a predetermined position of the pattern (e.g., a hydrophilic portion or a hydrophobic portion) in a state in which it can be transferred to a print substrate.

[0140] The ink is not particularly limited as long as it can be transferred to a substrate, and known inks such as water-based ink, oil-based ink, and emulsion ink can be used. When water-based ink is used, an ink film is formed on the hydrophilic parts of the pattern. When oil-based ink or emulsion ink is used, an ink film is formed on the hydrophobic parts of the pattern.

[0141] Then, by repeating the above-mentioned second stimulus application process, the process of forming a new image pattern, the cleaning process, the process of forming an ink film, and the printing process each time at least one sheet is printed, the printing plate can be repeatedly rewritten and printing can be performed.

[0142] [Printing device] A printing plate on which a pattern has been formed using the plate-making apparatus according to this embodiment can be mounted on a printing apparatus for printing. Fig. 7 is a perspective view showing the main parts of a printing apparatus for printing using the above-mentioned printing plate.

[0143] The printing apparatus shown in Fig. 7 is an offset printing apparatus. As shown in Fig. 7, the printing apparatus 100 includes a plate cylinder 101, a blanket 103, an impression cylinder 104, an ink roller 105, and a dampening water roller .

[0144] A printing plate 102, which has a pattern made up of printing areas and non-printing areas formed on its surface and which has been produced using the platemaking apparatus of the present invention, is attached to the surface of the plate cylinder 101. In the following description, the plate cylinder 101 and the printing plate 102 will be described as being one unit. Therefore, the surface of the plate cylinder 101 is also the surface of the printing plate 102.

[0145] For example, the image area can be a hydrophobic (oleophilic) area on which hydrophobic ink is carried, and the non-image area can be a hydrophilic area on which water is carried. As described above, the surface of the printing plate 102 is capable of rewriting the pattern formed by the image area and the non-image area.

[0146] Ink adhering to the plate cylinder 101 is transferred to the blanket 103, and the ink adhering to the blanket 103 is further transferred to the paper 200. The impression cylinder 104 pressurizes the paper 200 transported between the blanket 103 and the impression cylinder 104 toward the blanket 103. The ink roller 105 supplies ink supplied from an ink fountain or the like (not shown) to the plate cylinder 101. The dampening water roller 106 supplies water to the plate cylinder 101 for dampening the plate cylinder 101. The plate cylinder 101, blanket 103, impression cylinder 104, ink roller 105, and dampening water roller 106 rotate in synchronization with the transport of the paper 200 (in the direction of the illustrated arrows). The transport direction of the paper 200 is indicated by the illustrated arrow SF. Except for the printing plate portion, the configuration of the plate cylinder 101, blanket 103, impression cylinder 104, ink roller 105, and dampening water roller 106, and the printing operation are the same as those of a general offset printing apparatus.

[0147] That is, one embodiment of the present invention is a printing device having a plate cylinder on whose surface an ink forming printing plate on which a pattern has been formed using the platemaking apparatus of the present invention is mounted, a blanket in contact with the surface of the printing plate, an impression cylinder that sandwiches the printing medium between the blanket and the plate cylinder and presses the printing medium in the direction of the blanket, and an ink roller that supplies ink to the printing plate.

[0148] In addition, one embodiment of the present invention is a printing method using a printing device having a plate cylinder on the surface of which a printing plate can be attached, a blanket in contact with the surface of the printing plate, an impression cylinder that sandwiches the print medium between the blanket and the plate cylinder and presses the print medium toward the blanket, and an ink roller that supplies ink to the printing plate, the printing method including attaching an ink forming printing plate on which a pattern is formed using the plate making device of the present invention to the surface of the plate cylinder. By rewriting the printing plate using the plate making device as an external device, workability can be improved compared to the case where rewriting is performed by installing a writing means or an erasing means in the main part of the printing device shown in FIG. 7. In addition, the time loss in printing due to rewriting the printing plate can be reduced. EXAMPLES

[0149] The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. In the examples, the terms "parts" and "%" are used, but they represent "parts by mass" or "% by mass" unless otherwise specified.

[0150] <Synthesis of the azobenzene compound (azobenzene derivative (polymer 2)) represented by the above chemical formula (6)> 75 mL of 2.4N hydrochloric acid was added to 3-chloro-4-(hexyloxy)aniline (13.66 g, 60 mmol), and then a solution of sodium nitrite (4.98 g, 72 mmol) dissolved in 6 mL of distilled water was added while cooling and stirring at 0°C, and stirring was continued at 0°C for 60 minutes. A mixed solution of 2-chlorophenol (7.71 g, 60 mmol) and 24 mL of 20% aqueous sodium hydroxide solution was added to this solution, and stirring was continued for 20 hours. The precipitate was filtered, and the solid was washed with water. The obtained solid was purified by silica gel column chromatography using a mixture of ethyl acetate and hexane as a developing solvent, to obtain intermediate C (see reaction formula C above for the structure). To this intermediate C (7.35 g, 20 mmol), 100 mL of DMF, 3-bromo-1-hexanol (10.9 g, 60 mmol), and potassium carbonate (6.91 g, 50 mmol) were added, and the mixture was stirred at 80° C. for 2 hours, and then stirred at room temperature (25° C.) for 20 hours. After the solvent was distilled off under reduced pressure, the mixture was extracted with ethyl acetate, and the organic layer was washed with saturated saline and then dried over anhydrous magnesium sulfate. After filtering the mixture, the solvent was distilled off under reduced pressure, and the resulting solid was purified by silica gel column chromatography using a mixture of ethyl acetate and hexane as a developing solvent, to obtain intermediate D (see reaction formula C for the structure). To this intermediate D (4.67 g, 10 mmol), 100 mL of tetrahydrofuran was added to prepare a tetrahydrofuran solution of intermediate D. Separately, acryloyl chloride (1.09g, 12mmol) and triethylamine (2.43g, 24mmol) were added, and a tetrahydrofuran solution of intermediate D was added dropwise at 0°C. The mixture was stirred at 0°C for 30 minutes, then heated to room temperature (25°C), and further stirred at room temperature (25°C) for 2 hours. The obtained reaction solution was washed with water and saturated saline, and the solvent was distilled off under reduced pressure, and recrystallized with methanol to obtain intermediate E. 12mL of 20% aqueous sodium hydroxide solution was added to this intermediate E (2.61g, 5mmol), and the mixture was stirred at 340°C and 150atm for 2 hours, and then 10mL of 1.2N hydrochloric acid was added and stirred at room temperature (25°C) for 1 hour. The mixture was extracted with ethyl acetate, and the organic layer was washed with saturated saline, and then dried over anhydrous magnesium sulfate.After filtering, the solvent was distilled off under reduced pressure, and the obtained solid was purified by silica gel column chromatography using a mixture of ethyl acetate and hexane as a developing solvent to obtain intermediate F. 5 mL of tetrahydrofuran was added to this intermediate F (1.45 g, 3 mmol), and 5% by mass of 2,2-azobisisobutyronitrile (AIBN) was added as a polymerization initiator relative to intermediate F, and the mixture was stirred at 70° C. for 20 hours. Then, the mixture was reprecipitated using ethanol to obtain an azobenzene derivative (polymer 2) (see chemical formula (6) above). The obtained polymer 2 had a repeating unit x in chemical formula (6) of about 100.

[0151] (Preparation of ink film forming plate (M-1)) Dichloromethane (1200 parts by mass), toluene (1200 parts by mass), azobenzene derivative (polymer 2) (950 parts by mass) synthesized above as a photoresponsive compound, and styrene acrylic resin (SEIKO PMC Corporation, US-1071) (950 parts by mass) as a thermoplastic resin were mixed and stirred at 50°C for 1 hour to obtain a solution. This solution was thoroughly dispersed at room temperature (25°C) for 30 minutes using a paint shaker, and then applied to an electrolytically polished flat aluminum substrate (360 mm long x 180 mm wide) as a support using a blade coater so that the thickness after drying was 6 μm. After application, the plate was air-dried for 30 minutes, and then dried at 30°C for 2 hours using a vacuum dryer to obtain a printing plate (M-1) for forming an ink film.

[0152] When water was applied to the entire surface of the prepared printing plate for forming an ink film (M-1) using a water roller, the water was repelled, confirming that the surface was hydrophobic.

[0153] <Plate making equipment> (Plate making device A-1) 1 has a first stimulus applying section 1, a second stimulus applying section 2, and a cleaning section 3, and a printing plate 12 passes on a conveyor belt 11 in the order of the cleaning section 3, the second stimulus applying section 2, and the first stimulus applying section 1. A monochromatic laser light source with a wavelength of 465 nm is installed in the first stimulus applying section 1, a monochromatic laser light source with a wavelength of 365 nm is installed in the second stimulus applying section 2, and a cleaning roller 6 with a surface layer made of polyimide (PI) resin is installed in the cleaning section 3.

[0154] (Plate making device A-2) In the plate-making apparatus A-2, a cleaning roller 6 having a surface layer made of nylon resin was installed in the cleaning section 3. Other than that, the plate-making apparatus A-2 had the same configuration as the plate-making apparatus A-1 (not shown).

[0155] (Plate making device A-3) 2, in the plate-making apparatus A-3, a cleaning blade 7 made of polyurethane resin was installed in the cleaning section 3. Other than that, the plate-making apparatus A-3 had the same configuration as the plate-making apparatus A-1.

[0156] (Plate making device B-1) 3, plate making apparatus B-1 has an additional feature to plate making apparatus A-1, namely, an ink recovery unit 4 that contacts the cleaning roller 6. The ink recovery unit 4 recovers ink adhering to the cleaning roller 6 with a web (ink absorbent member 8) made of nonwoven fabric.

[0157] (Plate making device B-2) In the plate making apparatus B-2, the ink recovery section 4 uses a web (ink absorbent member 8) made of woven fabric to recover ink adhering to the cleaning roller 6. Other than that, the plate making apparatus B-2 has the same configuration as the plate making apparatus B-1 (not shown).

[0158] (Plate making device B-3) 4, in plate making apparatus B-3, the ink recovery section 4 passes cleaning paper 10 between the cleaning roller 6 and the pressure roller 9 in the direction of the arrow to recover the ink adhering to the cleaning roller 6 onto the cleaning paper 10. Other than that, the plate making apparatus B-3 has the same configuration as the plate making apparatus B-1.

[0159] (Plate making device C) 5, the plate-making apparatus C is configured by adding a third stimulus applying unit 5 immediately before the contact portion between the cleaning roller 6 and the printing plate 12 to the plate-making apparatus B-1. The third stimulus applying unit 5 is equipped with a monochromatic laser light source with a wavelength of 365 nm, the same as the second stimulus applying unit 2.

[0160] (Plate making device D) A plate making apparatus D having a configuration as shown in Fig. 6 has a first stimulus applying section 1, a second stimulus applying section 2, a cleaning roller 6, and a cleaning section 3 including an ink recovery section 4 in contact with the cleaning roller 6, and a printing plate 12 passes on a conveyor belt 11 in the order of the second stimulus applying section 2, the cleaning section 3, and the first stimulus applying section 1. A monochromatic laser light source with a wavelength of 465 nm is installed in the first stimulus applying section 1, a monochromatic laser light source with a wavelength of 365 nm is installed in the second stimulus applying section 2, and a cleaning roller 6 with a surface layer made of polyimide resin is installed in the cleaning section 3. The ink recovery section 4 recovers ink adhering to the cleaning roller 6 with a web (ink absorbent member 8) made of nonwoven fabric.

[0161] (Plate making equipment E) 8, plate-making apparatus E is configured similarly to plate-making apparatus D, with a third stimulus applying unit 5 being installed immediately before the contact portion between the cleaning roller 6 and the printing plate 12. The third stimulus applying unit 5 is equipped with a monochromatic laser light source with a wavelength of 365 nm, the same as the second stimulus applying unit 2.

[0162] (Plate making equipment F) A plate-making apparatus F having the configuration shown in Figure 9 has a first stimulus applying section 1 and a second stimulus applying section 2, and a printing plate 12 passes on a conveyor belt 11 in the order of the second stimulus applying section 2 and then the first stimulus applying section 1.

[0163] Example 1 The ink film forming plate (M-1) prepared above is passed through the plate making device A-1, and the entire surface layer of the plate is irradiated with a laser beam having a wavelength of 365 nm at a light intensity of 3 J / cm in the second stimulus applying section. 2 During this process, the cleaning roller was kept away from the plate surface, and cleaning with the cleaning roller was not performed prior to light irradiation in the second stimulus application section. After light irradiation, water was separately applied to the entire surface layer of the plate using a water roller. As the entire surface layer of the plate became uniformly wet, it was determined that light irradiation (irradiation amount 3 J / cm) by the second stimulus application section was the cause of the light irradiation. 2 ) and confirmed that the entire surface layer of the printing plate (M-1) had become hydrophilic. Next, in the first stimulus application section, monochromatic laser light having a wavelength of 465 nm was irradiated to the image section of the output image shown in FIG. 10 at a light intensity of 3 J / cm. 2 This resulted in the formation of an ink film-forming surface (m11) having a pattern in which the light-irradiated areas, i.e., image areas, became hydrophobic areas and the non-image areas became hydrophilic areas. Note that Fig. 10 is a diagram showing the pattern of the printing plate surface in the initial printing, and this pattern was an image area with a line width of 0.1 mm.

[0164] Next, the printing plate having this ink film forming surface (m11) was attached to the plate cylinder of an offset printing machine, and 1000 sheets were printed continuously. It was confirmed that the light irradiated area by the first stimulus applying unit was output as an image area.

[0165] The offset printing machine used was a LITHRONE 26 manufactured by Komori Corporation. The ink used was a hydrophobic ink from the TOYO KING NEX (registered trademark) series manufactured by Toyo Ink Co., Ltd., and printing was performed using Pearl Coat N manufactured by Mitsubishi Paper Mills as the printing medium.

[0166] Subsequently, the printing plate was removed from the offset printing machine, and the ink remaining on the printing plate was cleaned by the plate-making device A-1, the image pattern was erased by the second stimulus applying unit, and the image was rewritten by the first stimulus applying unit.

[0167] Specifically, the ink is cleaned using a cleaning roller with a surface made of polyimide resin, and the entire surface layer of the printing plate is irradiated with a laser beam with a wavelength of 365 nm at a light intensity of 3 J / cm in the second stimulus application section. 2 Next, the first stimulus applying unit irradiated the image portion of the output image shown in FIG. 11 with a monochromatic laser beam having a wavelength of 465 nm at a dose of 3 J / cm. 2 The plate was irradiated with light. FIG. 11 shows the pattern of the plate surface in rewriting, which is an image area with a line width of 0.1 mm. This resulted in the formation of an ink film forming surface (m12) having a pattern in which the light irradiated areas, i.e., the image areas, became hydrophobic areas and the non-image areas became hydrophilic areas. After the stimulation by the second stimulation unit, water was applied to the entire surface of the plate taken out without the stimulation by the first stimulation unit using a water roller. The entire surface of the plate was uniformly wetted, confirming that the pattern had been erased.

[0168] Next, the printing plate having this ink film forming surface (m12) was attached to the plate cylinder of an offset printing machine, and 100 sheets were printed continuously. The 100th printed image (the 100th printed image after rewriting) was subjected to the fogging evaluation described later.

[0169] (Stability of plate-making equipment during repeated use) Further, 10 consecutive printing plates were subjected to cleaning, erasing of the image pattern, and rewriting using the plate-making device A-1 in the above-mentioned manner. That is, 10 separate plates were prepared, and the steps of writing the pattern shown in FIG. 10, printing, cleaning, erasing the image pattern, and rewriting the pattern shown in FIG. 11 were sequentially carried out for each of the first to tenth plates. The tenth printing plate was attached to the plate cylinder of an offset printing machine, and 100 consecutive printings were carried out. The fogging evaluation described later was carried out for the 100th printed image (the 100th printed image after rewriting).

[0170] Example 2 The same evaluation as in Example 1 was carried out using the plate-making apparatus A-2.

[0171] Example 3 The same evaluation as in Example 1 was carried out using the plate-making apparatus A-3.

[0172] Example 4 Using the plate-making apparatus B-1, the same evaluation as in Example 1 was carried out in the same manner except for the points described below. The ink adhering to the cleaning roller was collected by a web made of nonwoven fabric. It was confirmed that the ink was removed from the cleaning roller after passing the web.

[0173] Example 5 Using the plate-making apparatus B-2, the same evaluation as in Example 1 was carried out in the same manner except for the points described below. The ink adhering to the cleaning roller was collected by a web made of woven fabric. It was confirmed that the ink was removed from the cleaning roller after passing the web.

[0174] Example 6 Using the plate making device B-3, the same evaluation as in Example 1 was carried out in the same manner except for the points described below. The ink adhering to the cleaning roller was collected by passing paper (cleaning paper) between the cleaning roller and the opposing pressure roller. It was confirmed that the ink was removed on the cleaning roller that had passed through the paper passing section.

[0175] Example 7 Using plate-making apparatus C, the same evaluation as in Example 1 was carried out in the same manner except for the points described below. Ink adhering to the cleaning roller was collected by a web made of nonwoven fabric, and the entire surface layer of the printing plate was irradiated with a laser beam having a wavelength of 365 nm at a light intensity of 1 J / cm at the third stimulus applying section 5 immediately before the cleaning roller. 2 The sample was irradiated with .

[0176] Example 8 Using plate-making apparatus D, the same evaluation as in Example 1 was performed in the same manner, except for the points described below. The image pattern was erased by the second stimulus applying unit, the ink remaining on the printing plate was cleaned, and the image was rewritten by the first stimulus applying unit, in that order. The ink adhering to the cleaning roller was collected by a web made of nonwoven fabric. It was confirmed that the ink had been removed from the cleaning roller after passing the web.

[0177] Example 9 Using plate-making apparatus E, the same evaluation as in Example 1 was carried out in the same manner, except for the points described below. The image pattern was erased by the second stimulus applying unit, the ink remaining on the printing plate was cleaned, and re-written by the first stimulus applying unit, in that order. The ink adhering to the cleaning roller was collected by a web made of nonwoven fabric, and the entire surface layer of the printing plate was irradiated with a laser beam having a wavelength of 365 nm at a light intensity of 1 J / cm by the third stimulus applying unit 5 immediately before the cleaning roller. 2 The sample was irradiated with .

[0178] Comparative Example 1 Using plate-making apparatus F, the same evaluation as in Example 1 was carried out in the same manner except for the points described below. Plate-making apparatus F does not have a cleaning unit, and when the printing plate removed from the offset printing machine after printing was rewritten by plate-making apparatus F, the pattern was erased by the second stimulus applying unit and rewritten by the first stimulus applying unit without removing the ink remaining on the plate.

[0179] [Evaluation method] <Fogging evaluation> The printed image was evaluated. For the evaluation, the rewritten patterns in each Example and Comparative Example were used for printing, and the printed image was enlarged with a digital microscope "VHX-600" (manufactured by Keyence Corporation). The obtained monitor image was observed with an indicator for fine lines, particularly fine lines in the portion corresponding to the pattern in FIG. 10, which is the initial image, and evaluated according to the following criteria. The previous image is the image of the initial print. If it is rated as ◎, ◯, or △, it can be used without any problems: ◎: No overlapping of previous image ○: The previous image is partially visible △: The previous image is slightly overlaid on the entire surface. ×: The overlay of the previous image is clearly visible.

[0180] The evaluation results are shown in Table 1 below.

[0181] [Table 1]

[0182] As is clear from Table 1 above, in Examples 1 to 9 using a platemaking apparatus having a first stimulus applying section, a second stimulus applying section, and a cleaning section, the 100th printed image on the first printing plate after rewriting had little fog of the previous image. This shows that the previous pattern can be sufficiently erased by cleaning the ink remaining on the printing plate.

[0183] In contrast, in Comparative Example 1, in which a platemaking device without a cleaning unit was used, the fog of the previous image was clearly visible in the printed image of the rewritten plate. This is thought to be because the ink remaining on the plate interfered with external stimuli, resulting in some areas where the pattern of the previous image could not be erased, and the pattern of the previous image was printed when printing was performed with the plate on which the new pattern was written.

[0184] Furthermore, in Examples 1 to 9 in which the printing plate apparatus of the present invention was used, there was little fogging even on the tenth printing plate, and it was found that patterns could be stably written and erased even when the plate-making apparatus was used repeatedly.

[0185] Comparing Examples 1 to 3, the use of a cleaning roller in the cleaning section reduces fogging even more.

[0186] Furthermore, fog was improved especially on the 10th plate by further providing an ink recovery section as in Examples 4 to 7. It is believed that fog was improved especially on the 10th plate by providing an ink recovery section, which can suppress deterioration of cleaning performance caused by ink accumulating in the cleaning section, and can reliably remove ink even during repeated use.

[0187] Furthermore, by further providing a third stimulus applying section as in Example 7, the ink was more reliably removed, and therefore fogging was improved especially on the tenth plate. [Explanation of symbols]

[0188] 1 first stimulus applying unit, 2 second stimulation unit; 3 Cleaning section, 4 Ink recovery section, 5 third stimulation unit; 6 cleaning roller, 7 cleaning blade, 8 ink absorbent member, 9 pressure roller, 10 cleaning paper, 11 conveyor belt, 12, 102 Printing plate for forming ink film, 100 printing equipment, 101 Print cylinder, 102 printing plate, 103 Blanket, 104 impression cylinder, 105 Ink Roller, 106 dampening water roller (water roller), 200 sheets of paper, A-1, A-3, B-1, B-3, C, D, E, F plate making equipment.

Claims

1. A plate-making apparatus for forming a pattern on an ink film-forming printing plate having a surface layer containing a stimulus-responsive compound whose physical properties reversibly change in response to an external stimulus, comprising: a first stimulus applying unit that applies a first stimulus to a surface of the printing plate, the first stimulus changing a physical property of the surface from a first physical property to a second physical property based on image data, thereby forming a pattern; a second stimulus applying unit that applies a second stimulus to a surface of the printing plate, the second stimulus changing a physical property of the surface from the second physical property to the first physical property, thereby erasing the pattern; a cleaning unit that removes ink remaining on the surface of the printing plate; having a plate-making apparatus, wherein the first stimulus and the second stimulus are lights having different wavelengths from each other, and the stimulus-responsive compound is a light-responsive compound selected from the group consisting of a compound having an azobenzene structure containing a hydrophilic group, a compound having a spiropyran structure containing a hydrophilic group, a compound having a stilbene structure containing a hydrophilic group, and a compound having a diarylethene structure containing a hydrophilic group.

2. 2. The plate making apparatus according to claim 1, wherein the cleaning section includes an abutment member that abuts against the printing plate, and the ink remaining on the printing plate is adhered to the abutment member by pressing the printing plate with the abutment member, thereby removing the ink.

3. 3. The plate making apparatus according to claim 2, wherein the contact member is a cleaning roller.

4. 4. The plate making apparatus according to claim 3, wherein the cleaning section further comprises an ink recovery section that recovers ink adhering to the cleaning roller.

5. 5. The plate making apparatus according to claim 4, wherein the ink recovery section includes an ink absorbing member selected from the group consisting of a woven fabric, a nonwoven fabric, and a sponge, which contacts the cleaning roller to absorb ink.

6. 5. The plate making apparatus according to claim 4, wherein the ink recovery section includes a pressure roller in contact with the cleaning roller and a cleaning paper passed between the cleaning roller and the pressure roller, and recovers ink adhering to the cleaning roller by transferring it to the cleaning paper.

7. A platemaking apparatus for forming a pattern on an ink film-forming printing plate having a surface layer containing a stimulus-responsive compound whose physical properties reversibly change in response to an external stimulus, comprising: a first stimulus applying unit that applies a first stimulus to a surface of the printing plate, the first stimulus changing a physical property of the surface from a first physical property to a second physical property based on image data, thereby forming a pattern; a second stimulus applying unit that applies a second stimulus to a surface of the printing plate, the second stimulus changing a physical property of the surface from the second physical property to the first physical property, thereby erasing the pattern; a cleaning unit for removing ink remaining on the surface of the printing plate; having the first stimulus and the second stimulus are lights having different wavelengths, and the stimulus responsive compound is a light responsive compound selected from the group consisting of a compound having an azobenzene structure containing a hydrophilic group, a compound having a spiropyran structure containing a hydrophilic group, a compound having a stilbene structure containing a hydrophilic group, and a compound having a diarylethene structure containing a hydrophilic group; or the first stimulus and the second stimulus are temperature changes different from each other, and the stimulus responsive compound is a temperature responsive compound; The plate-making apparatus, wherein the cleaning section further includes a third stimulus applying section that applies an external stimulus to at least one of the surface of the printing plate and the remaining ink at at least one of the stages before and simultaneously with the ink removal.

8. The plate making apparatus according to claim 7 , wherein the external stimulus applied by the third stimulus application unit is the same type of stimulus as the first stimulus or the second stimulus.

9. A platemaking device as described in any one of claims 1 to 8, wherein the physical properties of the surface of the printing plate change from hydrophobic to hydrophilic in response to the first stimulus and from hydrophilic to hydrophobic in response to the second stimulus, or the physical properties of the surface of the printing plate change from hydrophilic to hydrophobic in response to the first stimulus and from hydrophobic to hydrophilic in response to the second stimulus.

10. The plate making apparatus according to any one of claims 1 to 9, wherein the printing plate passes through the cleaning section, the second stimulus applying section, and the first stimulus applying section in that order, or the printing plate passes through the second stimulus applying section, the cleaning section, and the first stimulus applying section in that order.

11. The plate making apparatus according to claim 10 , wherein the printing plate passes through the cleaning section, the second stimulus applying section, and the first stimulus applying section in this order.

12. a first stimulus applying step of applying a first stimulus to a surface of a printing plate for forming an ink film, the first stimulus changing a physical property of the surface from a first physical property to a second physical property based on image data, to the surface of the printing plate for forming an ink film, the surface layer including a stimulus responsive compound whose physical property changes reversibly in response to an external stimulus, thereby forming a pattern; forming an ink film on either an image area or a non-image area of ​​the printing plate on which the pattern is formed; performing printing using the printing plate on which the ink film is formed; a second stimulus applying step of applying a second stimulus to a surface of the printing plate after printing, the second stimulus changing a physical property of the surface from the second physical property to the first physical property, thereby erasing the pattern; applying the first stimulus to the surface of the printing plate from which the pattern has been erased to form a new image pattern; a cleaning step of removing ink remaining on the surface of the printing plate after the printing step and before the second stimulus application step, or after the second stimulus application step and before the step of forming a new image pattern; having a photosensitive compound having a wavelength different from that of the first stimulus and a wavelength different from that of the second stimulus; and a photosensitive compound having a wavelength different from that of the second stimulus.

13. A printing method using a printing device having a plate cylinder on whose surface a printing plate can be attached, a blanket in contact with the surface of the printing plate, an impression cylinder that sandwiches a print medium between the blanket and the plate cylinder and presses the print medium in the direction of the blanket, and an ink roller that supplies ink to the printing plate, the printing method including attaching an ink film forming printing plate on which a pattern is formed using a platemaking device described in any one of claims 1 to 11 to the surface of the plate cylinder.

Images