JP2009175339A - Method of processing lithographic printing plate precursor and automatic developing device for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of processing a lithographic printing plate precursor and an automatic developing device for the same, keeping residual liquid developer for developing the lithographic printing plate precursor in a small quantity and constant, and manufacturing the lithographic printing plate precursor of a fixed quality without sticky touch on the plate surface. <P>SOLUTION: The lithographic printing plate precursor is dipped in the liquid developer, an image recording layer of the lithographic printing plate precursor is developed, and simultaneously protection processing for forming a surface protective film is performed, and a development squeeze roller is used for squeezing the liquid developer adhering to the developed lithographic printing plate precursor. The roller has a surface hardness of 20-40 degrees and a surface roughness of 8.0-15.0 μm at its maximum height (Ry). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a processing method for a lithographic printing plate precursor, and in particular, an image-exposed lithographic printing plate precursor is immersed in a developing solution, and the image recording layer of the lithographic printing plate precursor is developed imagewise. In addition, the present invention relates to a processing method for a lithographic printing plate precursor and a lithographic printing plate precursor automatic developing machine in which a protective treatment for forming a surface protective film is simultaneously performed.

  In general, a lithographic printing plate comprises an oleophilic image area that receives ink in the printing process and a hydrophilic non-image area that receives dampening water. Lithographic printing utilizes the property that water and printing ink repel each other, so that the oleophilic image area of the lithographic printing plate is the ink receiving area and the hydrophilic non-image area is dampened with the water receiving area (ink non-receiving area). As described above, a difference in ink adhesion is caused on the surface of a lithographic printing plate, and after ink is applied only to an image portion, the ink is transferred to a printing medium such as paper and printed.

  In order to produce this lithographic printing plate, conventionally, a lithographic printing plate precursor (PS plate) in which an oleophilic photosensitive resin layer (image recording layer) is provided on a hydrophilic support has been widely used. Usually, the lithographic printing plate precursor is exposed through an original image such as a lithographic film, and then the image portion of the image recording layer is left, and the other unnecessary image recording layer is removed with an alkaline developer or organic A lithographic printing plate is obtained by dissolving and removing with a solvent and performing a method of forming a non-image portion by exposing a hydrophilic support surface (see Patent Document 1).

  In the conventional plate making process of a lithographic printing plate precursor, after exposure, a step of dissolving and removing unnecessary image recording layers with a developer or the like is necessary. Treatment and less waste liquid are cited as issues. In particular, in recent years, the disposal of waste liquids accompanying wet processing has become a major concern for the entire industry due to consideration for the global environment, and thus the demand for solving the above problems has become stronger.

  On the other hand, in recent years, digitization technology for electronically processing, storing, and outputting image information by a computer has become widespread, and various new image output methods corresponding to such digitization technology will be put into practical use. It is becoming. Along with this, digitized image information is carried by high-convergence radiation such as laser light, and the lithographic printing plate precursor is scanned and exposed with that light, directly without using a lithographic film. Computer-to-plate technology for manufacturing is attracting attention. Accordingly, obtaining a lithographic printing plate precursor adapted to such a technique is one of the important technical issues.

  As mentioned above, the low alkali level of the developer and the simplification of the processing process are more strongly desired than ever in terms of consideration for the global environment and the adaptation to a small space and low running cost. It has become to. However, as described above, the development processing step generally involves heating the lithographic printing plate subjected to image exposure in a preheating unit for heating, then removing the protective layer in a pre-water washing unit for removing the protective layer, and then adjusting the pH to 10 or more. It consists of six steps of developing with an alkaline developer, further pouring an alkaline agent in a washing bath, then treating with a gum solution mainly containing a hydrophilic resin, and drying the plate surface. For this reason, the automatic developing machine itself takes a large space, and the pre-washing waste liquid, the developing waste liquid, the washing waste liquid, and the gum waste liquid are discharged, leaving problems in terms of environment and running cost.

Therefore, Patent Document 2 proposes a configuration example in which the development processing step is simplified and three steps of a pre-heating unit, a developing unit, and a drying unit are used.
For example, Patent Document 3 proposes a developing method using an alkaline solution containing a nonionic surfactant having a pH of 10 to 12.5. However, the developing method of Patent Document 3 involves the inclusion of an alkali-soluble polymer in the photosensitive composition, and there is a problem that development cannot be performed at a pH lower than that. Therefore, Patent Document 4 proposes a method of processing using a developer having a pH of 2 to 10.

JP 2003-107728 A European Patent Application Publication No. 1788442 JP 2002-91016 A JP 2006-39468 A

  For this reason, if the developing method of Patent Document 4 is applied to the developing device of Patent Document 2, it is possible to perform development processing in consideration of the environment and running cost in a space-saving manner, but the developer has adhered because there is no water washing and finishing process. You will touch the plate as it is. For this reason, there is a problem that the hand becomes sticky when a large amount of the processed printing plate is touched. In addition, in an automatic plate changing apparatus in which the developer component attached to the plate automatically attaches the printing plate to the printing press, slippage occurs due to the developer component attached to the plate, and the developer cannot be attached well. Further, since the developer component adhering to the plate is transferred to and accumulated in the plate cylinder of the printing press, the cleaning load is large, so that a practical level of processing cannot be performed.

This invention is made | formed based on such knowledge, The objective is as follows.
The present invention was made to solve the disadvantages of exposure and development processing of a lithographic printing plate precursor comprising a pre-heating unit for heating an image-exposed lithographic printing plate precursor, a developing unit, and a drying unit. It is an object of the present invention to provide a processing method for a lithographic printing plate precursor and an automatic developing apparatus for the lithographic printing plate precursor capable of producing a lithographic printing plate.

The object of the present invention is a processing method of a lithographic printing plate precursor for removing a non-image part of a lithographic printing plate precursor after image exposure of a lithographic printing plate precursor having an image recording layer on a support, A step of exposing the image to the image recording layer of the lithographic printing plate precursor and a protective treatment for immersing the lithographic printing plate precursor in a developer, developing the image recording layer of the lithographic printing plate precursor and forming a surface protective film are performed simultaneously. A developing squeeze roller having a roller surface hardness of 20 degrees to 40 degrees and a roller surface roughness of 8.0 μm to 15.0 μm at the maximum height (Ry). This is achieved by the processing method of the lithographic printing plate precursor.
Another object of the present invention is to provide an automatic developing device for a lithographic printing plate precursor for developing a lithographic printing plate precursor image-exposed on an image recording layer on a support, wherein the lithographic printing plate precursor is immersed in a developer. A pair of developments that rotate with respect to each other while sandwiching the lithographic printing plate precursor that is carried out from the development processing unit, and having a development processing unit that develops the image recording layer of the lithographic printing plate precursor and performs surface desensitization processing. A squeezing roller is provided in the development processing section, the development squeezing roller has a roller surface hardness of 20 to 40 degrees, and the roller surface has a maximum roughness (Ry) of 8.0 μm to 15.0 μm. This is achieved by an automatic developing device for a lithographic printing plate precursor using a squeezing roller. The lower roller of the pair of development squeezing rollers is preferably partially immersed in the developer. If the lower roller is not immersed in the developer, the developer adheres to the roller and dries, causing coating unevenness. On the other hand, when the lower roller is partially immersed in the developer, the upper roller and the lower roller are rotated while in contact with each other before the plate passes through the pair of rollers. The developer is supplied to the portion of the side roller not immersed in the developer, and the developer from the lower roller is supplied to the upper roller. , It dissolves in the developer, thereby eliminating coating unevenness.
The hardness is based on the measurement method of JIS K6253 Type A, and the maximum roughness height (Ry) is the standard curve length extracted from the roughness curve in the direction of the average line. This is the value measured in the direction of the vertical magnification of the roughness curve, and is defined in JIS B0601-1994.

  According to this processing method of the lithographic printing plate precursor, the hardness of the development squeeze roller on the roller is 20 degrees to 40 degrees, and the roughness of the roller surface is 5.0 μm to 15.0 μm at the maximum height (Ry). Therefore, the sticking of the plate surface can be prevented by suppressing the carry-out of the developer as much as possible. This makes it possible to stably produce a lithographic printing plate of a certain quality with a simple process.

  The roller hardness is 20 to 40 degrees, preferably 23 to 37 degrees, more preferably 25 to 35 degrees. The lower the roller hardness, the better the drawability. However, if the roller hardness is too soft, the roller is not suitable for manufacturing / processing.

  The surface roughness is 5.0 μm to 15.0 μm, preferably 7.0 μm to 13.0 μm or less, more preferably 7.5 μm to 12.0 μm in terms of maximum height (Ry). As the surface is denser, the drawability is improved. However, mirror finishing with a roller having a low rubber hardness is difficult to process and expensive. On the other hand, if the surface roughness is large, the squeezing property by which the developer is discharged from the roller surface is deteriorated. The surface roughness is not controlled by the roller rubber material and is devised by a polishing method. The polishing method includes wet polishing and dry polishing. In the present invention, it is preferable to process the roller surface using wet polishing.

The materials used for the developing diaphragm roller pair are isoprene rubber (IR / NR), styrene rubber (SBR), butadiene rubber (BR), nitrile rubber (NBR), ethylene propylene rubber (EPDM / EPM), butyl rubber (IIR), silicone Rubber (Si), chloropyrene rubber (CR), chlorosulfonated polyethylene (CSM), acrylic rubber (ACM), hydrin rubber (ECO), urethane rubber (U), polysulfide rubber (thiocol), fluoro rubber (FKM) Used. Preferably, styrene rubber (SBR), butadiene rubber (BR), nitrile rubber (NBR), ethylene propylene rubber (EPDM / EPM), butyl rubber (IIR), and silicone rubber (Si) are mentioned in terms of roller workability and cost. More preferred are nitrile rubber (NBR), ethylene propylene rubber (EPDM / EPM), butyl rubber (IIR), and silicone rubber (Si) because of their chemical resistance and durability.
The outer diameter of the roller is 20 to 200 mm, preferably 30 to 150 mm. If the outer diameter is large, the squeezability of the developer is improved, but the apparatus becomes large and the cost is increased. Among the roller outer diameters, the rubber wall thickness is 2 mm to 30 mm. Preferably they are 3 mm-25 mm, Preferably they are 5 mm-20 mm. The thicker the rubber wall, the better the squeezability of the developer, but the core metal diameter becomes thin and the deflection occurs.
The conveying roller nips at both ends. Therefore, the nip force is weakened due to the deflection at the center of the roller. Therefore, a roller shape that is thin toward the both ends of the roller, that is, a so-called crown shape can be used. The crown amount is preferably 0.4 to 2.0 mm (see JP-A-9-43809).

  Moreover, it is preferable that a surface protective film is a protective film formed by the desensitization process.

  By doing so, since the surface protective film is a protective film formed by the desensitization treatment, a lithographic printing plate having high printing durability can be obtained.

  Moreover, it is preferable that the main component of the processing liquid that performs the development process and the desensitizing process at the same time contains 3 to 20% by mass of a surfactant and the pH is 2 to 10.

  In this way, the main component of the processing liquid that simultaneously performs the development process and the desensitization process contains 3 to 20% by mass of a surfactant and has a pH of 2 to 10. And a lithographic printing plate comprising a photosensitive portion having high printing durability. That is, the pH of the developer of a normal lithographic printing plate is 12 or more, and when the developer is left standing, the pH is drastically lowered by carbon dioxide in the air, and the developer is rapidly deteriorated. On the other hand, since the pH of the developer of the present invention is 2 to 10, a decrease in pH due to carbon dioxide is suppressed, and the lifetime of the developer is prolonged. Further, if the pH of the developer is 2 to 10, the developability of the lithographic printing plate is lowered. Therefore, by adding 5 to 30% by weight of the surfactant, this decrease in developability is complemented. Can do.

  Moreover, it is preferable that the component of the processing liquid which performs a development process and a desensitization process simultaneously contains 1-10 mass% water-soluble resin.

  In this way, since the component of the processing liquid that simultaneously performs the development process and the desensitization process contains 1 to 10% by mass of the water-soluble resin, it can always be developed with a developing liquid having a constant developability, and is constant. Quality lithographic printing plates can be produced. In addition, since it contains a water-soluble resin, the plate surface can be protected and contamination of the non-image area can be prevented.

  The photosensitive layer of the lithographic printing plate precursor preferably contains a hydrophobic binder polymer, a polymerization initiator and a polymerizable compound.

  By so doing, the photosensitive layer of the lithographic printing plate precursor contains the hydrophobic binder polymer, whereby the film strength, water resistance and inking property of the photosensitive layer are improved, and printing durability is improved. Further, by containing a polymerization initiator and a polymerizable compound, ease of development and good printing durability can be obtained.

  According to the present invention, it is possible to produce a lithographic printing plate having a constant quality with little residual developer in the development processing of the lithographic printing plate precursor and being kept constant and without stickiness on the plate surface.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of a processing method for a lithographic printing plate precursor according to the invention will be described in detail with reference to the drawings.

<First Embodiment>
FIG. 1 is a configuration diagram of an automatic developing apparatus according to the first embodiment of the present invention, and FIG. 2 is a longitudinal sectional view showing a configuration of a photosensitive lithographic printing plate precursor.

This automatic developing device is applied to development processing of a photosensitive lithographic printing plate that has been image-exposed by an exposure device (not shown).
As shown in FIG. 1, the automatic developing apparatus 100 includes a pre-processing unit 200 that heats a photosensitive lithographic printing plate precursor (hereinafter also referred to as “PS plate”) 10, and a development processing unit that simultaneously performs development processing and gum processing. 300 and a drying unit 400.

  As shown in FIG. 2, the PS plate 10 developed by the automatic developing apparatus 100 of the present embodiment has a photosensitive layer 4 on one surface of a thin plate support 2 made of aluminum or the like via an adhesive layer 3. The plate is formed and provided with an overcoat layer 5 thereon. The PS plate 10 is subjected to image exposure by bringing a document film on which a document image is formed into close contact with the photosensitive surface, or directly by laser scanning exposure using digital data.

  In the pretreatment unit 200, the PS plate 10 is subjected to a preheating treatment prior to the development treatment. The PS plate 10 that has been pre-processed (pre-heated) by the pre-processing unit 200 is developed by the development processing unit 300. The development processing unit 300 has an arbitrary configuration capable of developing the PS plate 10. Can be used. Further, the pre-processing unit 200 applied to the present embodiment may be used separately from the development processing unit 300, or may be used by being connected to the development processing unit 300.

  In the pretreatment unit 200, a preheating unit 204 is provided in the machine casing 202 on the upstream side in the transport direction of the PS plate 10. In the preheating unit 204, a plurality of skewer rollers 210 are arranged in the heating chamber 208. In the heating chamber 208, a heater 214 is provided on the inlet 212 side, and a circulation fan 216 is provided on the downstream side of the heater 214.

  In the preheating unit 204, when the PS plate 10 passes through the heating chamber 208, the photopolymerization layer of the PS plate 10 is accurately cured so as to have a predetermined temperature and a predetermined heating time. The printing durability is increased by 10.

  A conveyance roller pair 304 is provided in the insertion section 302 of the development processing section 300.

  A processing tank 306 is provided in the development processing unit 300. In the processing tank 306, a developing tank 308 is formed as a processing tank. Further, the processing tank 306 is provided with a space for the insertion section 302 on the upstream side of the developing tank 308 (upstream side in the transport direction of the PS plate 10), and the drying section 400 is formed on the downstream side.

  In the outer panel 310 covering the periphery of the processing tank 306, a slit-shaped insertion port 312 is formed on the insertion side of the PS plate 10 into the development processing unit 300 (left side in FIG. 1). An insertion portion 302 is formed on the insertion port 312 side of the development processing unit 300.

  A rubber conveyance roller pair 304 is disposed in the insertion portion 302. The PS plate 10 whose image is exposed by an exposure apparatus (not shown) and preheated by the preheating unit 204 is inserted between the conveyance roller pair 304 by being inserted along the direction of arrow A from the insertion port 312. .

  The transport roller pair 304 is rotationally driven, and feeds the PS plate 10 into the development processing unit 300 at an angle in the range of about 15 ° to 31 ° with respect to the horizontal direction while being drawn from the insertion port 312. In the development processing unit 300 used for processing the single-sided PS plate 10, the photosensitive layer (photosensitive surface) is inserted through the insertion port 312 with the photosensitive layer (photosensitive surface) facing upward. That is, the PS plate 10 is processed by the development processing unit 300 with the photosensitive surface facing upward.

  The developing tank 308 formed in the processing tank 306 has a substantially mountain shape with the bottom center protruding downward, and a processing solution (hereinafter referred to as “desensitizing treatment”) for simultaneously performing the developing process and the desensitizing process of the PS plate 10. (Referred to as developer).

  In the developing tank 308, a conveyance roller 314 is disposed on the insertion portion 302 side that is upstream of the conveyance path 11 of the PS plate 10. Further, in the developing tank 308, a conveyance roller pair 316 is disposed in the central portion of the conveyance path 11 of the PS plate 10, and a conveyance roller pair 318 is disposed on the drying unit 400 side which is a downstream portion. Further, a liquid temperature sensor 336 is disposed on the downstream side of the conveying roller 314, and the temperature of the developer in the vicinity where the pre-heat-treated PS plate 10 is put into the developer is detected.

  In the developing tank 308 of the development processing unit 300, a guide plate 320 is provided between the conveyance roller 314 and the conveyance roller pair 316. One end of the guide plate 320 faces the conveyance roller 314, and the other end is directed between the conveyance roller pair 316.

  As a result, the PS plate 10 drawn into the developing processing unit 300 by the conveyance roller pair 304 is sent between the conveyance roller 314 and the guide plate 320 and guided and conveyed on the guide plate 320 to the conveyance roller pair 316. The

  In the developing tank 308, a brush roller 322 is disposed in the vicinity of the conveyance roller pair 316 so as to face the guide plate 320. The brush roller 322 is driven to rotate at a predetermined rotation direction and a predetermined rotation speed, and contacts the surface of the PS plate 10 conveyed on the guide plate 320, thereby brushing the upper surface of the PS plate 10. The guide plate 320 is disposed so that the brush roller 322 contacts the upper surface of the PS plate 10 with a predetermined brush pressure.

  The brush roller 322 protrudes from the liquid surface of the developing solution, and the upper portion protruding from the liquid surface of the brush roller 322 enters the concave portion of the shielding lid 324 together with the conveying roller pair 316. ing.

  On the other hand, in the developing tank 308, a brush roller 326 and a transport roller 328 are disposed between the transport roller pair 316 and 318. The brush roller 326 and the conveyance roller 328 are attached so as to face the upper surface side of the PS plate 10 conveyed between the conveyance roller pair 316 and 318. The brush roller 326 contacts the upper surface of the PS plate 10 while rotating in a predetermined direction and a predetermined rotation direction, thereby brushing the photosensitive layer on the upper surface side of the PS plate 10 and removing an unnecessary photosensitive layer with a developer. Has come to promote.

  The PS plate 10 drawn from the insertion port 312 by the conveyance roller pair 304 passes below the conveyance roller 314, is brushed by the brush roller 322, and is then fed between the conveyance roller pair 316. Thus, the toner is guided obliquely upward toward the conveying roller pair 318 along the bottom surface of the developing tank 308. At this time, the upper surface side of the PS plate 10 is brushed by the brush roller 326.

  Further, the conveying roller pair 318 is formed, for example, by a rubber roller at the outer periphery, and is fed into the drying unit 400 while sandwiching the PS plate 10 and pulling it out from the developing tank 308.

  In the developing tank 308, a spray pipe 330 is provided in the vicinity of the bottom surface between the transport roller pair 316 and the transport roller pair 318. The developer in the developing tank 308 sucked by a pump (not shown) is supplied to the spray pipe 330, and the developer is ejected from the spray pipe 330. Thereby, the developer in the developing tank 308 is agitated so that the PS plate 10 can be uniformly processed.

  The PS plate 10 drawn from the developing tank 308 by the conveying roller pair 318 is sent to the drying unit 400 while the developer attached to the surface is squeezed down by the conveying roller pair 318. The PS plate 10 developed and desensitized by the development processing unit 300 is sent to the drying unit 400 in a state where a little developer remains on the front and back surfaces (a state where the developer (gum solution) remains as a thin film).

  A partition plate 332 is provided between the development processing unit 300 and the drying unit 400. The partition plate 332 is disposed above the conveyance path 11 of the PS plate 10 so as to face the upper end of the processing tank 306, and thereby, a slit-shaped insertion between the development processing unit 300 and the drying unit 400. A mouth 334 is formed. The partition plate 332 has a double structure, whereby a groove-like air passage is formed on the drying unit 400 side of the insertion port 334, and air in the drying unit 400 enters the air passage. Thus, the air in the drying unit 400 is prevented from entering the development processing unit 300 from the insertion port 334.

  In the drying unit 400, a support roller 402 that supports the PS plate 10 is disposed in the vicinity of the insertion port 334, and in the vicinity of the central portion in the transport direction of the PS plate 10 and the discharge port 404. A roller pair 406 and a conveying roller pair 408 are disposed. The PS plate 10 is transported in the drying unit 400 by the support roller 402 and the transport roller pair 406 and 408.

  Ducts 410, 412 are disposed between the support roller 402 and the conveyance roller pair 406 and between the conveyance roller pair 406 and the conveyance roller pair 408 with the conveyance path 11 of the PS plate 10 interposed therebetween. . The ducts 410, 412 have a longitudinal direction arranged along the width direction of the PS plate 10, and a slit hole 414 is provided on the surface of the PS plate 10 facing the conveyance path 11.

  The ducts 410 and 412 discharge the dry air from the slit hole 414 toward the transport path 11 of the PS plate 10 when the dry air generated by the dry air generating means (not shown) is supplied from one end side in the longitudinal direction. And spray on the PS plate 10. Thereby, as for PS plate 10, the developing solution (gum solution) applied to the front and back is dried, and a protective film is formed.

  In the development processing unit 300, the shielding lid 324 is disposed in the developing tank 308 so as to prevent water evaporation in the developing solution in the developing tank 308. A blade-like shielding member (not shown) formed of silicon rubber or the like is provided between the shielding lid 324 and the processing tank 306 and the conveying roller 314 and the conveying roller pair 318, so that the developer in the developing tank 308 is fresh. It may be possible to prevent contact with outside air or evaporation of water in the developer, which is more preferable. Further, water may be replenished by the amount of water evaporation. As for water replenishment, there are two general methods: a method in which stop times are accumulated and accumulated at the start, and a method in which replenishment is performed at regular intervals during the operation time.

Below, the effect | action to the PS plate 10 in this embodiment is demonstrated.
In the pre-processing unit 200, when the PS plate 10 that has been image-exposed by an exposure device (not shown) is inserted into the pre-heating unit 204, the PS plate 10 conveyance process is started.

  In the exposure processing by the exposure apparatus, the PS plate 10 is exposed through a transparent original image having a line image, a halftone dot image, or the like, or is exposed imagewise by laser light scanning or the like using digital data. Examples of light sources suitable for exposure include carbon arc lamps, mercury lamps, xeno lamps, metal hydrado lamps, strobes, ultraviolet rays, infrared rays, and laser beams. A laser beam is particularly preferable, and examples include a solid-state laser and a semiconductor laser that emit infrared rays with a wavelength of 760 to 1200 nm, an ultraviolet semiconductor laser that emits light with a wavelength of 250 to 420 nm, an argon ion laser that emits visible light, and an FD-YAG laser. . Among these, a laser that emits infrared rays or ultraviolet rays is preferable from the viewpoint of simplification of plate making.

  Next, the PS plate 10 inserted from the insertion port is drawn into the machine casing 202 and fed into the heating chamber 208. The preheating unit 204 conveys the PS plate 10 fed into the heating chamber 208 while being heated by the heater 214. As a result, the PS plate 10 is heated at a preset heating temperature and heating time, and the degree of polymerization of the photopolymerization layer in the image area is increased to increase the printing durability, and the PS plate 10 is sent out.

  The PS plate 10 is sent out from the pre-processing unit 200 to the development processing unit 300 by sandwiching the end portion on the side carried out from the outlet 218 of the heating chamber 208 by the conveying roller pair 304 of the development processing unit 300.

  In the development processing unit 300, when the PS plate 10 on which an image is recorded by being exposed by an image exposure apparatus such as a printing apparatus (not shown) is inserted from the insertion port 312, the conveyance roller pair 304 is rotated. As a result, the PS plate 10 is sandwiched between the transport roller pair 304 and drawn into the development processing unit 300.

  The conveyance roller pair 304 sends the PS plate 10 drawn from the insertion port 312 to the developing tank 308 at an insertion angle in the range of 15 ° to 31 ° with respect to the horizontal direction as described above. As a result, the PS plate 10 is conveyed through the developing tank 308 by the conveying roller 314 and the conveying roller pairs 316 and 318 while being guided by the guide plate 320, and the developer (processing liquid) stored in the developing tank 308. And is sent out from the developer at a discharge angle in the range of 17 ° to 31 ° by the conveying roller pair 318.

  The PS plate 10 is immersed in a developing solution in the developing tank 308, so that the unnecessary photosensitive layer 4 is removed from the support 2 in accordance with the exposed image. At this time, in the development processing unit 300, the surface of the PS plate 10 (surface on the photosensitive layer side) is brushed by the brush rollers 322 and 326 arranged in the developing tank 308, so that the surface from the surface of the PS plate 10 is removed. The removal of unnecessary photosensitive layer 4 is promoted. Further, by dipping in the processing solution (developing solution), the gum solution contained in the processing solution is uniformly applied to the front and back surfaces of the PS plate 10 simultaneously with the developing process.

  The development process and the desensitization process are performed, and the PS plate 10 sent out from the developing tank 308 is sent to the drying unit 400 by the conveying roller pair 318. At this time, the conveyance roller pair 318 functions as a development squeeze roller, and squeezes the developer (processing solution) adhering to the PS plate 10 from the front and back surfaces of the PS plate 10, thereby forming the front and back surfaces of the PS plate 10. A uniform thin film of gum solution is formed.

  The PS plate 10 that has been subjected to the development process and the desensitization process (gum liquid application) in the development processing unit 300 is sent to the drying unit 400 from the insertion port 334. When a shutter is provided at the insertion opening 334, the insertion opening 334 is opened by operating the shutter at the timing when the processing of the PS plate 10 is started or when the PS plate 10 is sent out from the development processing unit 300. This prevents the drying air from the drying unit 400 from entering the development processing unit 300 unnecessarily when the PS plate 10 does not pass through, and prevents the gum solution from adhering to the conveying roller pair 318, and from the insertion port 334. Air is prevented from entering, and the moisture in the developer is prevented from evaporating and exiting from the insertion port 334. Further, the conveyance roller may be intermittently operated while it is stopped to prevent drying. During operation standby, the conveyance roller and the developing brush roller are rotated every 20 minutes for about 1 minute. The set time can be changed arbitrarily. Further, at the start of operation, the developer component stuck by rotating the conveying roller for about 5 to 60 minutes can be removed. The set time can be changed arbitrarily.

  In the drying unit 400, drying air is blown from the ducts 410, 412 to the front and back surfaces of the PS plate 10 while the PS plate 10 is conveyed by the support roller 402 and the conveying roller pair 406, 408. As a result, the PS plate 10 is discharged from the discharge port 404 with a protective film formed by the gum solution applied to the surface.

  In the development processing unit 300, the surface of the PS plate 10 (surface on the photosensitive layer side) is brushed (rubbed) by the brush rollers 322 and 326 arranged in the developing tank 308, so that the surface of the PS plate 10 is removed. The unnecessary removal of the photosensitive layer 4 is promoted, but the rubbing treatment with the brush rollers 322 and 326 has a great effect when it is performed after being immersed in the developer and after a certain period of time.

  In the development processing in the present embodiment, first, the developer penetrates into the photosensitive layer 4 of the PS plate 10, and thereafter, the photosensitive layer can be easily removed from the non-image area. Therefore, it is possible to efficiently remove the photosensitive layer 4 in a state where it is immersed in a developing solution in advance before the rubbing operation is performed. The elapsed time is 2 seconds or more according to experiments, more preferably 5 seconds or more, and still more preferably 10 seconds or more. Since the development processing is normally performed within 60 seconds, the elapsed time is inevitably shorter than 50 seconds.

  Here, before being immersed in the developer, the photosensitive layer 4 of the PS plate 10 can be brought into contact with the developer using a spray tube (not shown) or the like. In this case, since it takes a long time from the contact of the photosensitive layer 4 to the developer to the rubbing in which the development is performed in the developer, the development can be performed more efficiently. In addition, by bringing the developer into contact with the developer, it is possible to appropriately shorten the time from immersing in the developer to rubbing. Further, in order to promote the penetration of the developing solution, a method of vibrating the PS plate 10 while being in contact with the developing solution can be appropriately used.

  Therefore, if it is tsec after dipping in the developing solution until the PS plate 10 comes out of the developing solution, the rubbing treatment by the brush rollers 322 and 326 is preferably performed after t / 2 sec or after. . Therefore, it is desirable to perform development in the middle or the latter half of the developing tank 308. Of course, the rubbing treatment can be performed in the first half of the developing tank 308 if the developing tank 308 is lengthened or the conveying speed is slowed to increase the time of immersion in the developer. In order to provide stable development processing, rubbing processing by the brush rollers 322 and 326 is preferably performed in the middle or the latter half of the developing tank 308.

  The brush roller used in the present invention may be any member as long as it can rub the image recording surface of the PS plate 10, but in particular, the image recording surface can be rubbed by rotating around the rotation axis. It is preferable to use a member (for example, a known channel brush, twisting brush, implantation brush, carpet brush, and Morton roller).

  As channel brushes, long so-called channel brushes as disclosed in Japanese Utility Model Laid-Open Nos. 62-167253, 4-63447, 4-64128, and JP-A-6-186751. A (band-like brush) that is spirally wound around the surface of the roller body is used.

  As the torsion brush, the one in which a torsion brush is inserted into a spiral groove provided on the shaft as disclosed in JP-A-3-87832 and spirally wound around the shaft is used.

  As an implantation brush, what is created by the method of making a small hole in a shaft roller and implanting a brush material is used.

  As a carpet brush, an elongated belt in which a hair material is woven into a woven fabric is wound around the shaft roller as disclosed in JP 2001-5193 A and JP 2001-66788 A. Is used.

  As the Molton roller, a roller part as disclosed in Japanese Patent Laid-Open No. 10-198044 is covered with a cylindrical sliding contact material made of a knitted fabric made of fibers, and the end on the mounting side is tightened. it can.

  The rotational speed of the brush roller is preferably as fast as possible in order to improve the removability of the image recording layer of the non-exposed portion of the PS plate 10, but the durability of the automatic developing device 100, the manufacturing cost, the scattering of the developer, From the viewpoint of damage to the exposed portion of the PS plate 10, 30 to 1000 rpm, more preferably 50 to 500 rpm is preferable.

  The number of brush rollers may be one or more, and a plurality of brush rollers may be provided. In the case of two or more, one or more may be rotated in the direction opposite to the processing direction of the PS plate 10. Further, the developing process may be performed while swinging in the direction of the rotation axis. By swinging the brush roller in the rotation axis direction, the non-image part of the PS plate 10 can be removed more efficiently, and a higher quality lithographic printing plate can be produced.

  As the material of the brush used for the brush roller, natural fibers such as horse hair and pig hair, artificial fibers, metal fibers, and the like are known, but artificial fibers are preferable from the viewpoint of chemical resistance. Man-made fibers include polyamides such as nylon 6, nylon 6,6, nylon 6,10, nylon 6,12 and nylon 12, polyesters such as polyethylene terephthalate and polybutylene terephthalate (PBT), polyacrylonitrile, poly (meta ) Polyacrylics such as alkyl acrylate, polyolefins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride and polyvinylidene chloride, celluloses such as acetyl cellulose, polyurethanes such as polyurethane, polyphenylene sulfite, ethylene tetrafluoride Fluorine resins such as ethylene copolymers and polyvinylidene fluoride are used, but considering elasticity, rigidity, wear resistance, heat resistance, chemical resistance, water supply, moisture absorption, etc., nylon 6, nylon 6, 6, Nylon 6 · 10, Nai 6/12, nylon 12, polypropylene, polybutylene terephthalate, and polyethylene terephthalate are preferable. Nylon 6.6, nylon 6.10, 6.12, nylon 12, polybutylene terephthalate (PBT), and polypropylene are preferably used. . Of the polyesters, polybutylene terephthalate (PBT) is particularly preferable. Of the polyolefins, polypropylene is particularly preferred.

  The thickness of the brush hair is not particularly limited, but is preferably 0.01 mm to 1.0 mm, more preferably 0.1 mm to 0.5 mm. This is because if the thickness of the brush is thinner than 0.01 mm, the rubbing property is inferior, and if it is thicker than 1.0 mm, the plate surface is easily scratched. Further, the length of the brush bristles is not particularly limited, but is usually in the range of 3 mm to 50 mm. This is because if the length is shorter than 3 mm, the contact with the PS plate 10 becomes non-uniform and the plate surface is easily scratched. On the other hand, if the length is longer than 50 mm, no advantage in development processing can be found by increasing the length, which is disadvantageous economically. In the case of a Molton roller, since the cylindrical sliding contact material which consists of a knitted material is covered, regulation of the thickness and length of a hair material is unnecessary.

  As described above, according to the first embodiment, the PS plate 10 that has been desensitized simultaneously with development in the developing tank 308 is dried in the drying unit 400. At the same time as the cost can be reduced, the space can be saved, and the pretreatment unit (preheating unit) 200 is provided, so that the PS plate 10 having excellent printing durability can be manufactured.

  Here, the developer temperature in the normal development process is in the range of 20 ° C. to 40 ° C., preferably 25 ° C. to 35 ° C. If this temperature range is exceeded, if the temperature is increased by 5 ° C., the printing durability of the PS plate 10 is reduced, and if it is increased by 2 ° C., the photosensitive film is reduced. Further, when the temperature is lowered by 2 ° C., a residual film is formed on a part of the PS plate 10 due to insufficient development. Thus, the developer has a great influence on the development result even if the temperature change is only a few degrees. Therefore, it is important to lower the temperature of the plate surface 10a of the pre-heated PS plate 10 prior to development in order to obtain a high-quality printing plate.

In the development processing of a normal lithographic printing plate, the pH of the developer is 12 or more. Therefore, when the developer is left as it is, the pH is drastically lowered due to carbon dioxide in the air, and the developer is rapidly deteriorated. On the other hand, according to the development processing method of the present invention, since the pH of the developer is 2 to 10, the pH drop due to carbon dioxide is suppressed. Thereby, the lifetime of a developing solution can be lengthened.
Further, when the pH of the developer is 2 to 10, the developability of the lithographic printing plate is lowered. Therefore, the surfactant is added in an amount of 5 to 30% by weight in order to improve the developability. As a result, it is possible to supplement the decrease in developability caused by the low pH, and maintain good developability.

Next, a non-alkaline aqueous solution used as a developer will be described.
<Aqueous solution used as developer>
A lithographic printing plate precursor (PS plate) is image-exposed with a light source of 350 nm to 450 nm, and then the plate surface is rubbed with a rubbing member in the presence of an aqueous solution (developer) having a pH of 2 to 10, whereby a protective layer and non-exposed Part of the photosensitive layer is removed, and an image can be formed on the surface of the aluminum plate support.
The aqueous solution used in the present invention is an aqueous solution having a pH of 2 to 10. For example, water alone or an aqueous solution containing water as a main component (containing 60% by mass or more of water) is preferable. In particular, an aqueous solution having the same composition as that of a generally known fountain solution, a surfactant (anionic, nonionic, An aqueous solution containing a cationic system or an amphoteric system) or an aqueous solution containing a water-soluble polymer compound is preferred. In particular, an aqueous solution containing both a surfactant and a water-soluble polymer compound is preferable. The pH of the aqueous solution is more preferably 3-9, still more preferably 4-8.

  Examples of the anionic surfactant used in the present invention include fatty acid salts, abietic acid salts, hydroxyalkane sulfonic acid salts, alkane sulfonic acid salts, dialkyl sulfosuccinic acid salts, linear alkyl benzene sulfonic acid salts, branched alkyl benzene sulfonic acid salts, Alkylnaphthalene sulfonates, alkylphenoxy polyoxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, N-methyl-N-oleyl taurine sodium, N-alkyl sulfosuccinic acid monoamide disodium salts, petroleum sulfonates , Sulfated castor oil, sulfated beef tallow oil, fatty acid alkyl ester sulfates, alkyl sulfates, polyoxyethylene alkyl ether sulfates, fatty acid compounds Glyceryl sulfate ester salt, polyoxyethylene alkylphenyl ether sulfate ester salt, polyoxyethylene styryl phenyl ether sulfate ester salt, alkyl phosphate ester salt, polyoxyethylene alkyl ether phosphate ester salt, polyoxyethylene alkylphenyl ether phosphate ester salt, styrene -Partial saponifications of maleic anhydride copolymer, partial saponifications of olefin-maleic anhydride copolymer, naphthalene sulfonate formalin condensate and the like. Among these, dialkyl sulfosuccinates, alkyl sulfate esters and alkyl naphthalene sulfonates are particularly preferably used.

  It does not specifically limit as a cationic surfactant used for this invention, A conventionally well-known thing can be used. Examples thereof include alkylamine salts, quaternary ammonium salts, polyoxyethylene alkylamine salts, and polyethylene polyamine derivatives.

  Nonionic surfactants used in the present invention include polyethylene glycol type higher alcohol ethylene oxide adduct, alkylphenol ethylene oxide adduct, fatty acid ethylene oxide adduct, polyhydric alcohol fatty acid ester ethylene oxide adduct, higher alkylamine ethylene. Oxide adduct, fatty acid amide ethylene oxide adduct, fat and oil ethylene oxide adduct, polypropylene glycol ethylene oxide adduct, dimethylsiloxane-ethylene oxide block copolymer, dimethylsiloxane- (propylene oxide-ethylene oxide) block copolymer, etc. Alcohol-type glycerol fatty acid ester, pentaerythritol fatty acid ester, sorbitol and sorbita Fatty acid esters of fatty acid esters of sucrose, alkyl ethers of polyhydric alcohols, fatty acid amides of alkanolamines.

  These nonionic surfactants may be used alone or in admixture of two or more. In the present invention, ethylene oxide adduct of sorbitol and / or sorbitan fatty acid ester, polypropylene glycol ethylene oxide adduct, dimethylsiloxane-ethylene oxide block copolymer, dimethylsiloxane- (propylene oxide-ethylene oxide) block copolymer, polyhydric alcohol Fatty acid esters are more preferred.

  The amphoteric surfactant used in the present invention is not particularly limited, and conventionally known ones can be used. For example, an alkyl carboxybetaine form, an alkylaminocarboxylic acid form, and an alkyl imidazoline form can be mentioned. These surfactants may be used alone or in combination of two or more.

  Further, from the viewpoint of stable solubility or turbidity in water, the nonionic surfactant used in the aqueous solution of the present invention preferably has an HLB (HydoropHile-LipopHile Balance) value of 6 or more, preferably 8 or more. It is more preferable that Furthermore, the ratio of the nonionic surfactant contained in the aqueous solution is preferably 0.01 to 10% by weight, and more preferably 0.01 to 5% by weight. Further, acetylene glycol-based and acetylene alcohol-based oxyethylene adducts, fluorine-based and silicon-based surfactants can be used in the same manner.

  The aqueous solution of the present invention may contain a water-soluble polymer compound. Examples of water-soluble polymer compounds include soybean polysaccharide, modified starch, gum arabic, dextrin, fibrin derivatives (eg, carboxymethylcellulose, carboxyethylcellulose, methylcellulose, etc.) and modified products thereof, pullulan, polyvinyl alcohol and derivatives thereof, polyvinylpyrrolidone, Examples include polyacrylamide and acrylamide copolymers, vinyl methyl ether / maleic anhydride copolymers, vinyl acetate / maleic anhydride copolymers, styrene / maleic anhydride copolymers, and the like.

  A well-known thing can be used for the said soybean polysaccharide, for example, there exists a brand name Soya Five (made by Fuji Oil Co., Ltd.) as a commercial item, and the thing of various grades can be used. What can be preferably used is one in which the viscosity of a 10% by mass aqueous solution is in the range of 10 to 100 mPa / sec.

As the modified starch, known ones can be used, and starch such as corn, potato, tapioca, rice and wheat is decomposed with acid or enzyme in the range of 5 to 30 glucose residues per molecule, and further in an alkali. It can be made by a method of adding oxypropylene or the like.
Two or more water-soluble polymer compounds can be used in combination. The content of the water-soluble polymer compound in the aqueous solution is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass.

  In addition to the above, the aqueous solution of the present invention may contain preservatives, chelate compounds, antifoaming agents, organic acids, inorganic acids, inorganic salts and the like.

  Preservatives include phenol or derivatives thereof, formalin, imidazole derivatives, sodium dehydroacetate, 4-isothiazolin-3-one derivatives, benzisothiazolin-3-one, benztriazole derivatives, amiding anidine derivatives, quaternary ammonium salts, pyridine, Derivatives such as quinoline and guanidine, diazine, triazole derivatives, oxazole, oxazine derivatives, nitrobromoalcohol-based 2-bromo-2-nitropropane-1,3diol, 1,1-dibromo-1-nitro-2-ethanol, 1,1-dibromo-1-nitro-2-propanol and the like can be preferably used.

  Examples of the chelate compound include ethylenediaminetetraacetic acid, potassium salt thereof, sodium salt thereof; diethylenetriaminepentaacetic acid, potassium salt thereof, sodium salt thereof; triethylenetetraminehexaacetic acid, potassium salt thereof, sodium salt thereof, hydroxyethylethylenediaminetriacetic acid Nitrilotriacetic acid, sodium salt; 1-hydroxyethane-1,1-diphosphonic acid, potassium salt, sodium salt; aminotri (methylenephosphonic acid), potassium salt, sodium salt And organic phosphonic acids and phosphonoalkanetricarboxylic acids. Organic amine salts are also effective in place of the sodium and potassium salts of the chelating agents.

  As the antifoaming agent, a general silicon-based self-emulsifying type, emulsifying type, or nonionic surfactant having a HLB of 5 or less can be used. Silicon antifoaming agents are preferred. Among them, emulsification dispersion type and solubilization can be used.

  Examples of organic acids include citric acid, acetic acid, succinic acid, malonic acid, salicylic acid, caprylic acid, tartaric acid, malic acid, lactic acid, levulinic acid, p-toluenesulfonic acid, xylenesulfonic acid, phytic acid, and organic phosphonic acid. . The organic acid can also be used in the form of its alkali metal salt or ammonium salt.

  Examples of inorganic acids and inorganic salts include phosphoric acid, metaphosphoric acid, primary ammonium phosphate, secondary ammonium phosphate, primary sodium phosphate, secondary sodium phosphate, primary potassium phosphate, secondary potassium phosphate, Examples include sodium tripolyphosphate, potassium pyrophosphate, sodium hexametaphosphate, magnesium nitrate, sodium nitrate, potassium nitrate, ammonium nitrate, sodium sulfate, potassium sulfate, ammonium sulfate, sodium sulfite, ammonium sulfite, sodium hydrogen sulfate, nickel sulfate and the like.

[Lithographic printing plate precursor]
Next, the planographic printing plate precursor used in the present invention will be described.

<Photosensitive layer>
The lithographic printing plate precursor used in the plate making method of the present invention has a negative photosensitive layer on which the photosensitive layer in the exposed area is cured. The negative photosensitive layer is not particularly limited, but is a radically polymerizable photosensitive layer containing a hydrophobic binder polymer, a polymerization initiator and a polymerizable compound from the viewpoint of easy development and good printing durability. Is preferred. Hereinafter, the components of the photosensitive layer will be described.

(Hydrophobic binder polymer)
As the hydrophobic binder polymer that can be used in the photosensitive layer, a water-insoluble polymer is preferably used. Further, the usable hydrophobic binder polymer preferably does not substantially contain an acid group such as a carboxyl group, a sulfone group, and a phosphoric acid group, and the acid value of the binder polymer (chemical content, etc. per 1 g of the polymer) It is preferable that it is 0.3 meq / g or less, More preferably, it is 0.1 meq / g or less.

  That is, the usable hydrophobic binder polymer is preferably insoluble in water and an aqueous solution having a pH of 10 or more, and the solubility of the hydrophobic binder polymer in water and an aqueous solution having a pH of 10 or more is 0.5% by mass or less. Is more preferable, and 0.1% by mass or less is more preferable. By using such a hydrophobic binder polymer, the film strength, water resistance, and inking property of the photosensitive layer are improved, and printing durability is improved.

As the hydrophobic binder polymer, as long as the performance of the lithographic printing plate is not impaired, a conventionally known one can be used without limitation within the above range, and a linear organic polymer having a film property is preferable.
As an example of such a hydrophobic binder polymer, a polymer selected from acrylic resin, polyvinyl acetal resin, polyurethane resin, polyamide resin, epoxy resin, methacrylic resin, styrene resin, and polyester resin is preferable. Especially, an acrylic resin is preferable and a (meth) acrylic acid ester copolymer is preferable. More specifically, an alkyl (meth) acrylate or an aralkyl ester and an ester residue (—COOR) of (meth) acrylate ester may have —CH ₂ CH ₂ O— unit or —CH ₂ CH ₂ NH— unit as R. A copolymer with a (meth) acrylic acid ester containing is particularly preferred. The preferable alkyl group of the (meth) acrylic acid alkyl ester is an alkyl group having 1 to 5 carbon atoms, and a methyl group is more preferable. Preferable (meth) acrylic acid aralkyl esters include benzyl (meth) acrylate.

Furthermore, the hydrophobic binder polymer can be provided with a crosslinking property in order to improve the film strength of the image area.
In order to impart crosslinkability to the binder polymer, a crosslinkable functional group such as an ethylenically unsaturated bond may be introduced into the main chain or side chain of the polymer. The crosslinkable functional group may be introduced by copolymerization or may be introduced by a polymer reaction.

  Further, it is preferable that the binder polymer is hydrophilic from the viewpoint of improving developability with respect to an aqueous solution, and it is important that the binder polymer is compatible with the polymerizable compound contained in the photosensitive layer from the viewpoint of improving printing durability. Yes, ie lipophilic. From such a viewpoint, it is also effective to copolymerize a hydrophilic group and a lipophilic group in a hydrophobic binder polymer in order to improve developability and printing durability. Examples of the hydrophilic group include a hydroxy group, a carboxylate group, a hydroxyethyl group, an ethyleneoxy group, a hydroxypropyl group, a polyoxyethyl group, a polyoxypropyl group, an amino group, an aminoethyl group, an aminopropyl group, and an ammonium group. And those having a hydrophilic group such as an amide group or a carboxymethyl group.

The hydrophobic binder polymer preferably has a weight average molecular weight of 5,000 or more, more preferably 10,000 to 300,000, and a number average molecular weight of 1,000 or more, preferably 2000 to 250,000. Is more preferable. The polydispersity (weight average molecular weight / number average molecular weight) is preferably 1.1 to 10.
The hydrophobic binder polymer may be any of a random polymer, a block polymer, a graft polymer, and the like, but is preferably a random polymer.

  The hydrophobic binder polymer may be used alone or in combination of two or more. The content of the hydrophobic binder polymer is 5 to 90% by mass, preferably 10 to 70% by mass, and more preferably 10 to 60% by mass with respect to the total solid content of the photosensitive layer. Within this range, good image area strength and image formability can be obtained.

(Polymerization initiator)
The polymerization initiator is a compound that generates radicals by light or thermal energy and initiates and accelerates polymerization of a compound having a polymerizable unsaturated group. As such a radical generator, a known polymerization initiator or a compound having a bond having a small bond dissociation energy can be appropriately selected and used.

  Examples of the compounds that generate radicals include organic halogen compounds, carbonyl compounds, organic peroxides, azo polymerization initiators, azide compounds, metallocene compounds, hexaarylbiimidazole compounds, organic boron compounds, disulfone compounds, and oximes. Examples thereof include ester compounds and onium salt compounds.

  Specific examples of the organic halogen compound include Wakabayashi et al., “Bull Chem. Soc Japan” 42, 2924 (1969), US Pat. No. 3,905,815, Japanese Patent Publication No. 46-4605, JP 48-36281, JP 53-133428, JP 55-3070, JP 60-239736, JP 61-169835, JP 61-169837, JP 62- 58241, JP-A 62-212401, JP-A 63-70243, JP-A 63-298339, PHutt, “Journal of Heterocyclic Chemistry”, 1 (No. 3) (1970). Of these, oxazole compounds and S-triazine compounds substituted with a trihalomethyl group are preferred.

  The polymerization initiator is not limited to the above, but a triazine-based initiator, an organic halogen compound, an oxime ester compound, a diazonium salt, an iodonium salt, and a sulfonium salt are more preferable from the viewpoints of reactivity and stability.

  These polymerization initiators may be used alone or in combination of two or more. Moreover, these polymerization initiators may be added to the same layer as other components, or another layer may be provided and added thereto. These polymerization initiators are preferably from 0.1 to 50% by mass, more preferably from 0.5 to 30% by mass, particularly preferably from 0.8 to 20% by mass, based on the total solid content constituting the photosensitive layer. Can be added.

(Infrared absorber)
In the photosensitive layer of the lithographic printing plate precursor that performs imagewise exposure using a light source that emits infrared rays, an infrared absorber can be used in combination with the polymerization initiator. In general, an infrared absorber has a function of converting absorbed infrared rays into heat, and the polymerization initiator is thermally decomposed by the heat generated at this time to generate radicals. The infrared absorber is a dye or pigment having an absorption maximum at a wavelength of 760 to 1200 nm.

  As the dye, commercially available dyes and known dyes described in documents such as “Dye Handbook” (edited by the Society for Synthetic Organic Chemistry, published in 1970) can be used. Specifically, dyes such as azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, metal thiolate complexes Is mentioned.

  Examples of pigments include commercially available pigment and color index (CI) manuals, “Latest Pigment Handbook” (edited by the Japan Pigment Technology Association, published in 1977), “Latest Pigment Applied Technology” (published by CMC, published in 1986), “Printing” The pigments described in "Ink Technology", published by CMC Publishing, 1984) can be used.

  Examples of the pigment include black pigments, yellow pigments, orange pigments, brown pigments, red pigments, purple pigments, blue pigments, green pigments, fluorescent pigments, metal powder pigments, and other polymer-bonded dyes. Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelate azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments , Quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black, and the like. Among these pigments, carbon black is preferable.

  These pigments may be used without surface treatment, or may be used after surface treatment. The surface treatment method includes a method of surface coating with resin or wax, a method of attaching a surfactant, a method of bonding a reactive substance (eg, silane coupling agent, epoxy compound, polyisocyanate, etc.) to the pigment surface, etc. Can be considered. The above-mentioned surface treatment methods are described in “Characteristics and Application of Metal Soap” (Shobobo), “Printing Ink Technology” (CMC Publishing, 1984) and “Latest Pigment Application Technology” (CMC Publishing, 1986). Yes.

  The particle diameter of the pigment is preferably in the range of 0.01 to 10 μm, more preferably in the range of 0.05 to 1 μm, and particularly preferably in the range of 0.1 to 1 μm. Within this range, good stability of the pigment dispersion in the photosensitive layer coating solution and good uniformity of the photosensitive layer can be obtained.

  As a method for dispersing the pigment, a known dispersion technique used for ink production or toner production can be used. Examples of the disperser include an ultrasonic disperser, a sand mill, an attritor, a pearl mill, a super mill, a ball mill, an impeller, a disperser, a KD mill, a colloid mill, a dynatron, a three-roll mill, and a pressure kneader. Details are described in "Latest Pigment Applied Technology" (CMC Publishing, 1986).

The addition of these infrared absorbers to the photosensitive layer is preferably made the minimum necessary amount in order to suppress side effects that inhibit the polymerization reaction.
These infrared absorbers may be added in a proportion of 0.001 to 50% by mass, preferably 0.005 to 30% by mass, particularly preferably 0.01 to 10% by mass, based on the total solid content of the photosensitive layer. it can. Within this range, high sensitivity can be obtained without adversely affecting the uniformity and film strength of the photosensitive layer.

(Sensitizing dye)
Radical generation efficiency can also be increased by using a sensitizing dye in combination with the polymerization initiator in the photosensitive layer of a lithographic printing plate precursor that performs imagewise exposure using a light source that emits light of 250 to 420 nm. .

  Specific examples of the sensitizing dye include benzoin, benzoin methyl ether, benzoin ethyl ether, 9-fluorenone, 2-chloro-9-fluorenone, 2-methyl-9-fluorenone, 9-anthrone, and 2-bromo-9-anthrone. 2-ethyl-9-anthrone, 9,10-anthraquinone, 2-ethyl-9,10-anthraquinone, 2-t-butyl-9,10-anthraquinone, 2,6-dichloro-9,10-anthraquinone, xanthone 2-methylxanthone, 2-methoxyxanthone, thioxanthone, benzyl, dibenzalacetone, p- (dimethylamino) phenyl styryl ketone, p- (dimethylamino) phenyl p-methylstyryl ketone, benzophenone, p- (dimethylamino) ) Benzophenone (or Michalake) Emissions), p- (diethylamino) benzophenone, benzanthrone, 2,5-bis (4-diethylamino-phenyl) such as 1,3,4-oxadiazole and the like.

Details of the usage such as which structure of these sensitizing dyes are used, whether they are used alone or in combination of two or more, and how much is added, can be appropriately set according to the performance design of the final photosensitive material. .
For example, the compatibility with the photosensitive composition layer can be enhanced by using two or more sensitizing dyes in combination. In selecting the sensitizing dye, in addition to the photosensitivity, the molar extinction coefficient at the emission wavelength of the light source used is an important factor. By using a dye having a large molar extinction coefficient, the amount of the dye added can be made relatively small, which is economical and advantageous from the viewpoint of film physical properties of the photosensitive layer when used for a lithographic printing plate precursor. It is. The photosensitivity of the photosensitive layer, the resolution, and the physical properties of the exposed film are greatly affected by the absorbance at the light source wavelength. Therefore, the addition amount of the sensitizing dye is appropriately selected in consideration of these factors.

  These sensitizing dyes are preferably 0.1 to 50% by mass, more preferably 0.5 to 30% by mass, and particularly preferably 0.8 to 20% by mass with respect to the total solid content constituting the photosensitive layer. Can be added.

(Polymerizable compound)
The polymerizable compound used in the photosensitive layer is an addition polymerizable compound having at least one ethylenically unsaturated double bond, and is selected from compounds having at least one, preferably two or more terminal ethylenically unsaturated bonds. Such a compound group is widely known in the industrial field, and these can be used without any particular limitation. These have chemical forms such as monomers, prepolymers, i.e. dimers, trimers and oligomers, or mixtures thereof and copolymers thereof. Examples of monomers and copolymers thereof include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), and esters and amides thereof. In this case, an ester of an unsaturated carboxylic acid and an aliphatic polyhydric alcohol compound, or an amide of an unsaturated carboxylic acid and an aliphatic polyvalent amine compound is used. In addition, an addition reaction product of an unsaturated carboxylic acid ester or amide having a nucleophilic substituent such as a hydroxyl group, amino group or mercapto group with a monofunctional or polyfunctional isocyanate or epoxy, and monofunctional or polyfunctional A dehydration condensation reaction product with a functional carboxylic acid is also preferably used. Further, an addition reaction product of an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an epoxy group or an epoxy group with a monofunctional or polyfunctional alcohol, amine or thiol, a halogen group or In addition, a substitution reaction product of an unsaturated carboxylic acid ester or amide having a leaving substituent such as a tosyloxy group and a monofunctional or polyfunctional alcohol, amine or thiol is also suitable. As another example, it is also possible to use a group of compounds substituted with unsaturated phosphonic acid, styrene, vinyl ether or the like instead of the unsaturated carboxylic acid.

  Specific examples of the monomer of an ester of an aliphatic polyhydric alcohol compound and an unsaturated carboxylic acid include acrylic acid esters such as ethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butanediol diacrylate, and tetramethylene glycol. Diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolpropane tri (acryloyloxypropyl) ether, trimethylolethane triacrylate, hexanediol diacrylate, 1,4-cyclohexanediol diacrylate , Tetraethylene glycol diacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate , Pentaerythritol tetraacrylate, dipentaerythritol diacrylate, dipentaerythritol hexaacrylate, sorbitol triacrylate, sorbitol tetraacrylate, sorbitol pentaacrylate, sorbitol hexaacrylate, tri (acryloyloxyethyl) isocyanurate, isocyanuric acid ethylene oxide (EO) Examples include modified triacrylates and polyester acrylate oligomers.

  Methacrylic acid esters include tetramethylene glycol dimethacrylate, triethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, ethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, Hexanediol dimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol dimethacrylate, dipentaerythritol hexamethacrylate, sorbitol trimethacrylate, sorbitol tetramethacrylate, bis [p- (3-methacryloxy- 2-hydroxypro ) Phenyl] dimethyl methane, bis - [p- (methacryloxyethoxy) phenyl] dimethyl methane.

  Itaconic acid esters include ethylene glycol diitaconate, propylene glycol diitaconate, 1,3-butanediol diitaconate, 1,4-butanediol diitaconate, tetramethylene glycol diitaconate, pentaerythritol diitaconate And sorbitol tetritaconate. Examples of crotonic acid esters include ethylene glycol dicrotonate, tetramethylene glycol dicrotonate, pentaerythritol dicrotonate, and sorbitol tetradicrotonate. Examples of isocrotonic acid esters include ethylene glycol diisocrotonate, pentaerythritol diisocrotonate, and sorbitol tetraisocrotonate. Examples of maleic acid esters include ethylene glycol dimaleate, triethylene glycol dimaleate, pentaerythritol dimaleate, and sorbitol tetramaleate.

  Examples of other esters include aliphatic alcohol esters described in JP-B-51-47334 and JP-A-57-196231, JP-A-59-5240, JP-A-59- Those having an aromatic skeleton described in JP-A No. 5241 and JP-A-2-226149 and those containing an amino group described in JP-A-1-165613 are also preferably used. Furthermore, the ester monomers described above can also be used as a mixture.

  Specific examples of amide monomers of aliphatic polyvalent amine compounds and unsaturated carboxylic acids include methylene bis-acrylamide, methylene bis-methacrylamide, 1,6-hexamethylene bis-acrylamide, 1,6-hexamethylene bis. -Methacrylamide, diethylenetriamine trisacrylamide, xylylene bisacrylamide, xylylene bismethacrylamide and the like. Examples of other preferable amide monomers include those having a cyclohexylene structure described in JP-B No. 54-21726.

  Also, urethane acrylates such as those described in JP-A-51-37193, JP-B-2-32293, JP-B-2-16765, JP-B-58-49860, JP-B-56- Urethane compounds having an ethylene oxide skeleton described in Japanese Patent No. 17654, Japanese Patent Publication No. 62-39417, and Japanese Patent Publication No. 62-39418 are also suitable. Furthermore, addition polymerizable compounds having an amino structure or a sulfide structure in the molecule described in JP-A-63-277653, JP-A-63-260909, and JP-A-1-105238 are used. Depending on the case, it is possible to obtain a photopolymerizable composition excellent in the photosensitive speed.

  Other examples include polyester acrylates, epoxy resins and (meth) acrylic acid as described in JP-A-48-64183, JP-B-49-43191, JP-B-52-30490, and JP-A-52-30490. Mention may be made of polyfunctional acrylates and methacrylates such as reacted epoxy acrylates. In addition, specific unsaturated compounds described in JP-B-46-43946, JP-B-1-40337, JP-B-1-40336, and vinylphosphonic acid-based compounds described in JP-A-2-25493 are also included. Can be mentioned. In some cases, a structure containing a perfluoroalkyl group described in JP-A-61-22048 is preferably used. Furthermore, Journal of Japan Adhesion Association vol. 20, no. 7, pages 300 to 308 (1984), which are introduced as photocurable monomers and oligomers, can also be used.

About these polymerizable compounds, the details of usage such as the structure, single use or combination, addition amount and the like can be arbitrarily set according to the performance design of the final lithographic printing plate precursor. For example, it is selected from the following viewpoints.
From the viewpoint of sensitivity, a structure having a large unsaturated group content per molecule is preferable, and in many cases, a bifunctional or higher functionality is preferable. Further, in order to increase the strength of the image area, that is, the cured film, those having three or more functionalities are preferable. A method of adjusting both sensitivity and strength by using a compound) is also effective.
In addition, the compatibility and dispersibility with other components in the photosensitive layer (for example, binder polymer, polymerization initiator, colorant, etc.), the selection and use method of the polymerizable compound is an important factor. In some cases, the compatibility can be improved by using a low-purity compound or by using two or more kinds in combination. In addition, a specific structure may be selected for the purpose of improving adhesion to a support or a protective layer described later.

  The polymerizable compound is preferably used in the range of 5 to 80% by mass, more preferably 25 to 75% by mass, based on the total solid content of the photosensitive layer. These may be used alone or in combination of two or more. In addition, the usage of the polymerizable compound can be arbitrarily selected from the viewpoint of polymerization inhibition with respect to oxygen, resolution, fogging, refractive index change, surface adhesiveness, etc. The layer construction and coating method such as undercoating and overcoating can also be carried out.

(Microcapsule)
As a method for incorporating the above photosensitive layer constituents and other constituents described later into the photosensitive layer, for example, as described in JP-A Nos. 2001-277740 and 2001-277742, some of the constituents are included. Can be encapsulated in microcapsules and added to the photosensitive layer. In that case, each component can be contained in any ratio in and out of the microcapsule.

  As a method for microencapsulating the photosensitive layer constituent components, known methods can be applied. For example, as a method for producing microcapsules, a method using coacervation found in U.S. Pat. Nos. 2,800,547 and 2,800,498, U.S. Pat. No. 3,287,154, JP-B-38-19574, 42-446 by the interfacial polymerization method, US Pat. No. 3,418,250, US Pat. No. 3,660,304 by polymer precipitation method, US Pat. No. 3,796,669, isocyanate polyol A method using a wall material, a method using an isocyanate wall material found in US Pat. No. 3,914,511, and a urea-formaldehyde system found in US Pat. Nos. 4,001,140, 4,087,376 and 4,089,802. Or urea formaldehyde-resorcino A method using a wall forming material, a method using a wall material such as melamine-formaldehyde resin and hydroxycellulose, as shown in US Pat. No. 4,025,445, and Japanese Patent Publication Nos. 36-9163 and 51-9079. In situ method using monomer polymerization, spray drying method found in British Patent No. 930422, US Pat. No. 3,111,407, electrolytic dispersion cooling method seen in British Patent Nos. 952807 and 967074, etc. However, it is not limited to these.

  A preferable microcapsule wall has three-dimensional cross-linking and a property of swelling with a solvent. From such a viewpoint, the wall material of the microcapsule is preferably polyurea, polyurethane, polyester, polycarbonate, polyamide, and a mixture thereof, and particularly preferably polyurea and polyurethane. Moreover, you may introduce | transduce into the microcapsule wall the compound which has crosslinkable functional groups, such as an ethylenically unsaturated bond which can be introduce | transduced into said water-insoluble polymer.

  The average particle size of the microcapsules is preferably 0.01 to 3.0 μm. 0.05-2.0 micrometers is further more preferable, and 0.10-1.0 micrometer is especially preferable. Within this range, good resolution and stability over time can be obtained.

(Other photosensitive layer components)
The photosensitive layer of the present invention can further contain various additives as required. These will be described below.

(Surfactant)
In the photosensitive layer, it is preferable to use a surfactant in order to promote developability and improve the coated surface state. Examples of the surfactant include nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants, and fluorosurfactants. Surfactant may be used independently and may be used in combination of 2 or more type.

  A nonionic surfactant is not specifically limited, A conventionally well-known thing can be used. For example, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene polystyryl phenyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, glycerin fatty acid partial esters, sorbitan fatty acid partial esters, pentaerythritol Fatty acid partial esters, propylene glycol mono fatty acid esters, sucrose fatty acid partial esters, polyoxyethylene sorbitan fatty acid partial esters, polyoxyethylene sorbitol fatty acid partial esters, polyethylene glycol fatty acid esters, polyglycerin fatty acid partial esters, Polyoxyethylenated castor oil, polyoxyethylene glycerin fatty acid partial esters, fatty acid diethanolamides, N N- bis-2-hydroxyalkylamines, polyoxyethylene alkylamines, triethanolamine fatty acid ester, trialkylamine oxide, polyethylene glycol, copolymers of polyethylene glycol and polypropylene glycol.

  An anionic surfactant is not specifically limited, A conventionally well-known thing can be used. For example, fatty acid salts, abietic acid salts, hydroxyalkane sulfonates, alkane sulfonates, dialkyl sulfosuccinate esters, linear alkyl benzene sulfonates, branched alkyl benzene sulfonates, alkyl naphthalene sulfonates, alkyl phenoxy poly Oxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, N-methyl-N-oleyl taurine sodium salt, N-alkyl sulfosuccinic acid monoamide disodium salt, petroleum sulfonates, sulfated beef oil, fatty acid alkyl esters Sulfates, alkyl sulfates, polyoxyethylene alkyl ether sulfates, fatty acid monoglyceride sulfates, polyoxyethylene alcohol Ruphenyl ether sulfates, polyoxyethylene styryl phenyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkyl phenyl ether phosphates, styrene / maleic anhydride Examples thereof include partial saponification products of polymers, partial saponification products of olefin / maleic anhydride copolymers, and naphthalene sulfonate formalin condensates.

  A cationic surfactant is not specifically limited, A conventionally well-known thing can be used. Examples thereof include alkylamine salts, quaternary ammonium salts, polyoxyethylene alkylamine salts, and polyethylene polyamine derivatives.

  An amphoteric surfactant is not specifically limited, A conventionally well-known thing can be used. Examples thereof include carboxybetaines, aminocarboxylic acids, sulfobetaines, aminosulfuric esters, and imidazolines.

  Of the above surfactants, the term “polyoxyethylene” can be read as “polyoxyalkylene” such as polyoxymethylene, polyoxypropylene, polyoxybutylene, etc. Can be used.

  More preferable surfactants include fluorine-based surfactants containing a perfluoroalkyl group in the molecule. Examples of such fluorosurfactants include anionic types such as perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, and perfluoroalkyl phosphates; amphoteric types such as perfluoroalkyl betaines; Cation type such as trimethylammonium salt; perfluoroalkylamine oxide, perfluoroalkylethylene oxide adduct, oligomer containing perfluoroalkyl group and hydrophilic group, oligomer containing perfluoroalkyl group and lipophilic group, perfluoroalkyl Nonionic types such as an oligomer containing a group, a hydrophilic group and a lipophilic group, and a urethane containing a perfluoroalkyl group and a lipophilic group. Also preferred are the fluorosurfactants described in JP-A-62-170950, JP-A-62-226143 and JP-A-60-168144.

Surfactant can be used individually or in combination of 2 or more types.
The content of the surfactant is preferably 0.001 to 10% by mass and more preferably 0.01 to 7% by mass with respect to the total solid content of the photosensitive layer.

(Hydrophilic polymer)
In order to improve developability and dispersion stability of microcapsules, a hydrophilic polymer can be contained.
Examples of the hydrophilic polymer include hydroxy group, carboxyl group, carboxylate group, hydroxyethyl group, polyoxyethyl group, hydroxypropyl group, polyoxypropyl group, amino group, aminoethyl group, aminopropyl group, ammonium group, Preferred examples include those having a hydrophilic group such as an amide group, carboxymethyl group, sulfonic acid group, and phosphoric acid group.

  Specific examples include gum arabic, casein, gelatin, starch derivatives, carboxymethylcellulose and its sodium salt, cellulose acetate, sodium alginate, vinyl acetate-maleic acid copolymers, styrene-maleic acid copolymers, polyacrylic acids and their salts, Polymethacrylic acids and their salts, homopolymers and copolymers of hydroxyethyl methacrylate, homopolymers and copolymers of hydroxyethyl acrylate, homopolymers and copolymers of hydroxypropyl methacrylate, homopolymers and copolymers of hydroxypropyl acrylate, homopolymers of hydroxybutyl methacrylate Polymers and copolymers, homopolymers and copolymers of hydroxybutyl acrylate Polyethylene glycols, hydroxypropylene polymers, polyvinyl alcohols, hydrolyzed polyvinyl acetate, polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone, acrylamide homopolymers and copolymers having a hydrolysis degree of 60 mol% or more, preferably 80 mol% or more , Homopolymers and polymers of methacrylamide, homopolymers and copolymers of N-methylolacrylamide, polyvinylpyrrolidone, alcohol-soluble nylon, polyether of 2,2-bis- (4-hydroxyphenyl) -propane and epichlorohydrin, etc. Is mentioned.

The hydrophilic polymer preferably has a weight average molecular weight of 5000 or more, more preferably 10,000 to 300,000. The hydrophilic polymer may be any of a random polymer, a block polymer, a graft polymer, and the like.
The content of the hydrophilic polymer in the photosensitive layer is preferably 20% by mass or less, more preferably 10% by mass or less, based on the total solid content of the photosensitive layer.

(Coloring agent)
A dye having a large absorption in the visible light region can be used as an image colorant. Specifically, Oil Yellow # 101, Oil Yellow # 103, Oil Pink # 312, Oil Green BG, Oil Blue BOS, Oil Blue # 603, Oil Black BY, Oil Black BS, Oil Black T-505 (orientated chemistry) Kogyo Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI42555), Methyl Violet (CI42535), Ethyl Violet, Rhodamine B (CI145170B), Malachite Green (CI42000), Methylene Blue (CI522015), etc., and JP-A-62-2 And dyes described in Japanese Patent No. 293247. Also, pigments such as phthalocyanine pigments, azo pigments, carbon black, titanium oxide, etc. can be suitably used.

  These colorants are preferably added since it is easy to distinguish an image area from a non-image area after image formation. The amount added is preferably 0.01 to 10% by mass with respect to the total solid content of the image recording material.

(Bake-out agent)
In the photosensitive layer, a compound that changes color by an acid or a radical can be added to produce a printout image. As such a compound, for example, various dyes such as diphenylmethane, triphenylmethane, thiazine, oxazine, xanthene, anthraquinone, iminoquinone, azo, and azomethine are effectively used.

  Specific examples include brilliant green, ethyl violet, methyl green, crystal violet, basic fuchsin, methyl violet 2B, quinaldine red, rose bengal, methanyl yellow, thymol sulfophthalein, xylenol blue, methyl orange, paramethyl red, Congo Fred, Benzopurpurin 4B, α-Naphthyl Red, Nile Blue 2B, Nile Blue A, Methyl Violet, Malachide Green, Parafuchsin, Victoria Pure Blue BOH [manufactured by Hodogaya Chemical Co., Ltd.], Oil Blue # 603 [Orient Chemical Kogyo Co., Ltd.], Oil Pink # 312 [Orient Chemical Co., Ltd.], Oil Red 5B [Orient Chemical Co., Ltd.], Oil Scarlet # 308 [Orient Gaku Kogyo Co., Ltd.], Oil Red OG [Orient Chemical Co., Ltd.], Oil Red RR [Orient Chemical Co., Ltd.], Oil Green # 502 [Orient Chemical Co., Ltd.], Spiron Red BEH Special [made by Hodogaya Chemical Co., Ltd.], m-cresol purple, cresol red, rhodamine B, rhodamine 6G, sulforhodamine B, auramine, 4-p-diethylaminophenyliminonaphthoquinone, 2-carboxyanilino-4-p- Diethylaminophenyliminonaphthoquinone, 2-carboxystearylamino-4-pN, N-bis (hydroxyethyl) amino-phenyliminonaphthoquinone, 1-phenyl-3-methyl-4-p-diethylaminophenylimino-5-pyrazolone, 1-β-naphthyl-4- - dyes and p of diethylamino phenyl imino-5-pyrazolone, p ', p "- hexamethyl triamnotriphenylmethane (leuco crystal violet), and a leuco dye such as Pergascript Blue SRB (manufactured by Ciba-Geigy).

  A suitable addition amount of the dye that changes color by acid or radical is 0.01 to 15% by mass relative to the solid content of the photosensitive layer.

(Polymerization inhibitor)
A small amount of a thermal polymerization inhibitor is preferably added to the photosensitive layer in order to prevent unnecessary thermal polymerization of the radical polymerizable compound during the production or storage of the photosensitive layer.
Examples of the thermal polymerization inhibitor include hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,4'-thiobis (3-methyl-6-t- (Butylphenol), 2,2'-methylenebis (4-methyl-6-tert-butylphenol), N-nitroso-N-phenylhydroxylamine aluminum salt are preferred.
The addition amount of the thermal polymerization inhibitor is preferably about 0.01 to about 5% by mass with respect to the total solid content of the photosensitive layer.

(Higher fatty acid derivatives, etc.)
In order to prevent polymerization inhibition by oxygen, a higher fatty acid derivative such as behenic acid or behenic acid amide may be added to the photosensitive layer and may be unevenly distributed on the surface of the photosensitive layer in the drying process after coating. . The amount of the higher fatty acid derivative added is preferably from about 0.1 to about 10% by weight based on the total solid content of the photosensitive layer.

(Plasticizer)
The photosensitive layer may contain a plasticizer. Examples of the plasticizer include phthalates such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diisobutyl phthalate, dioctyl phthalate, octyl capryl phthalate, dicyclohexyl phthalate, ditridecyl phthalate, butyl benzyl phthalate, diisodecyl phthalate, diallyl phthalate; Glycol esters such as glycol phthalate, ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, butyl phthalyl butyl glycolate, triethylene glycol dicaprylate; Phosphate esters such as tricresyl phosphate and triphenyl phosphate Diisobutyl adipate, dioctyl adipate, dimethyl sebacate, dibutyl sebacate, dioct Ruazereto, aliphatic dibasic acid esters such as dibutyl maleate; polyglycidyl methacrylate, triethyl citrate, glycerin triacetyl ester, butyl laurate in. The plasticizer content is preferably about 30% by mass or less based on the total solid content of the photosensitive layer.

(Inorganic fine particles)
The photosensitive layer may contain inorganic fine particles in order to improve the strength of the cured film in the image area. As the inorganic fine particles, for example, silica, alumina, magnesium oxide, titanium oxide, magnesium carbonate, calcium alginate or a mixture thereof can be preferably mentioned. Even if they are not photothermally convertible, they can be used for strengthening the film, enhancing interfacial adhesion by surface roughening, and the like. The inorganic fine particles preferably have an average particle size of 5 nm to 10 μm, and more preferably 0.5 to 3 μm. Within the above range, it is possible to form a non-image portion excellent in hydrophilicity that is stably dispersed in the photosensitive layer, sufficiently retains the film strength of the photosensitive layer, and does not easily cause stains during printing.
The inorganic fine particles as described above can be easily obtained as a commercial product such as a colloidal silica dispersion.
The content of the inorganic fine particles is preferably 20% by mass or less, and more preferably 10% by mass or less, based on the total solid content of the photosensitive layer.

(Low molecular hydrophilic compound)
The photosensitive layer can contain a hydrophilic low molecular weight compound for improving developability. Examples of the hydrophilic low-molecular compound include water-soluble organic compounds such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol and the like, and ether or ester derivatives thereof, glycerin, Polyhydroxys such as pentaerythritol, organic amines such as triethanolamine and diethanolamine monoethanolamine and salts thereof, organic sulfonic acids such as toluenesulfonic acid and benzenesulfonic acid and salts thereof, organic phosphonic acids such as phenylphosphonic acid and the like Organic carboxylic acids such as salts, tartaric acid, oxalic acid, citric acid, malic acid, lactic acid, gluconic acid, amino acids and their salts, and organic quaternary amines such as tetraethylamine hydrochloride Salt, and the like.

  In addition to the above, the photosensitive layer can contain, for example, a cosensitizer.

<Formation of photosensitive layer>
The photosensitive layer is formed by preparing or applying a coating solution by dispersing or dissolving the necessary components described above in a solvent. Solvents used here include ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, dimethoxy Examples include ethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyllactone, toluene, water, and the like. However, the present invention is not limited to this. These solvents are used alone or in combination. The solid content concentration of the coating solution is preferably 1 to 50% by mass.
The photosensitive layer of the present invention can be formed by preparing a plurality of coating solutions in which the same or different components are dispersed or dissolved in the same or different solvents, and repeatedly applying and drying a plurality of times.

The coating, the photosensitive layer coating amount on the support obtained after drying (solid content) may be varied according to the intended purpose, generally 0.3 to 3.0 g / m ² is preferred. Within this range, good sensitivity and good film properties of the image recording layer can be obtained.
Various methods can be used as a coating method. Examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.

<Protective layer>
The lithographic printing plate precursor is preferably provided with a protective layer (oxygen blocking layer) on the photosensitive layer in order to block diffusion and penetration of oxygen that hinders the polymerization reaction during exposure. The protective layer preferably has an oxygen permeability A of 1.0 ≦ A ≦ 20 (mL / m ² · day) at 25 ° C. and 1 atm. When the oxygen permeability A is extremely low at less than 1.0 (mL / m ² · day), unnecessary polymerization reaction occurs at the time of production and raw storage, and unnecessary fogging and image streaking occur during image exposure. The problem that fatness arises arises. Conversely, when the oxygen permeability A exceeds 20 (mL / m ² · day) and is too high, the sensitivity is lowered. The oxygen permeability A is more preferably in the range of 1.5 ≦ A ≦ 12 (mL / m ² · day), more preferably 2.0 ≦ A ≦ 10.0 (mL / m ² · day). In addition to the oxygen permeability described above, the properties desired for the protective layer further do not substantially inhibit the transmission of light used for exposure, have excellent adhesion to the photosensitive layer, and are easy in the development process after exposure. It is desirable that it can be removed. The device concerning such a protective layer has been conventionally made, and is described in detail in US Pat. No. 3,458,311 and JP-B-55-49729.

  As a material that can be used for the protective layer, for example, a water-soluble polymer compound having relatively excellent crystallinity is preferably used. Specifically, polyvinyl alcohol, vinyl alcohol / vinyl phthalate copolymer, vinyl acetate / vinyl are used. Examples include water-soluble polymers such as alcohol / vinyl phthalate copolymer, vinyl acetate / crotonic acid copolymer, polyvinyl pyrrolidone, acidic celluloses, gelatin, gum arabic, polyacrylic acid, and polyacrylamide. Or they can be mixed. Of these, the use of polyvinyl alcohol as the main component gives the best results in terms of basic properties such as oxygen barrier properties and development removability.

  The polyvinyl alcohol used for the protective layer may be partially substituted with an ester, an ether, and an acetal as long as it contains an unsubstituted vinyl alcohol unit for having necessary oxygen barrier properties and water solubility. Similarly, some of them may have other copolymer components. Specific examples of polyvinyl alcohol include those having a hydrolysis rate of 71 to 100 mol% and a polymerization repeating unit in the range of 300 to 2400. Specifically, Kuraray Co., Ltd. PVA-105, PVA-110, PVA-117, PVA-117H, PVA-120, PVA-124, PVA-124H, PVA-CS, PVA-CST, PVA-HC, PVA-203, PVA-204, PVA-205, PVA-210, PVA-217, PVA-220, PVA-224, PVA-217EE, PVA-217E, PVA-220E, PVA-224E, PVA-405, PVA- 420, PVA-613, L-8 and the like, and these can be used alone or in combination. In a preferred embodiment, the content of polyvinyl alcohol in the protective layer is 20 to 95% by mass, and more preferably 30 to 90% by mass.

  Moreover, well-known modified polyvinyl alcohol can also be used preferably. For example, various hydrophilic modification sites such as anion modification sites modified with anions such as carboxyl groups and sulfo groups, cation modification sites modified with cations such as amino groups and ammonium groups, silanol modification sites, and thiol modification sites are randomly selected. Polyvinyl alcohol having various degrees of polymerization, the anion-modified site, the cation-modified site, the silanol-modified site, the thiol-modified site, the alkoxyl-modified site, the sulfide-modified site, and the ester modification of vinyl alcohol and various organic acids. Examples thereof include polyvinyl alcohol having various polymerization degrees having various modified sites such as a site, an ester-modified site of the anion-modified site and alcohols, an epoxy-modified site, and the like.

  As a component used by mixing with polyvinyl alcohol, polyvinyl pyrrolidone or a modified product thereof is preferable from the viewpoint of oxygen barrier properties and development removability, and the content in the protective layer is 3.5 to 80% by mass, preferably 10 to 60%. It is 15 mass%, More preferably, it is 15-30 mass%.

  Components of the protective layer (selection of PVA, use of additives), coating amount, and the like are selected in consideration of fogging, adhesion, and scratch resistance in addition to oxygen barrier properties and development removability. In general, the higher the hydrolysis rate of the PVA used (the higher the content of the unsubstituted vinyl alcohol unit in the protective layer), the higher the film thickness, the higher the oxygen barrier property and the more advantageous in terms of sensitivity. The molecular weight of the (co) polymer such as polyvinyl alcohol (PVA) can be in the range of 2000 to 10 million, preferably in the range of 20,000 to 3 million.

  As another composition of the protective layer, glycerin, dipropylene glycol and the like can be added in an amount corresponding to several mass% with respect to the (co) polymer to provide flexibility. Anionic surfactants such as sodium acid salts; amphoteric surfactants such as alkylaminocarboxylates and alkylaminodicarboxylates; nonionic surfactants such as polyoxyethylene alkylphenyl ethers to the (co) polymer Mass% can be added.

  In addition, adhesion to the image area and scratch resistance are extremely important in handling the plate. That is, when a hydrophilic layer made of a water-soluble polymer is laminated on an oleophilic photosensitive layer, film peeling due to insufficient adhesion tends to occur, and the peeled part causes defects such as poor film hardening due to inhibition of oxygen polymerization. On the other hand, various proposals have been made to improve the adhesion between these two layers. For example, in U.S. Patent Application No. 292,501 and U.S. Patent Application No. 44,563, an acrylic emulsion or a water-insoluble vinyl pyrrolidone-vinyl acetate copolymer is contained in a hydrophilic polymer mainly composed of polyvinyl alcohol. It is described that sufficient adhesiveness can be obtained by mixing 20 to 60% by mass and laminating on a photosensitive layer. Any of these known techniques can be applied to the protective layer in the present invention. Such a coating method for the protective layer is described in detail in, for example, US Pat. No. 3,458,311 and Japanese Patent Publication No. 55-49729.

Furthermore, the protective layer in the lithographic printing plate precursor preferably contains an inorganic layered compound for the purpose of improving oxygen barrier properties and photosensitive layer surface protection.
Here, the inorganic layered compound is a particle having a thin flat plate shape. For example, the following general formula: A (B, C) _2-5 D ₄ O ₁₀ (OH, F, O) ₂ [wherein A is any one of K, Na, and Ca, B and C are any one of Fe (II), Fe (III), Mn, Al, Mg, and V, and D is Si or Al. And mica groups such as natural mica and synthetic mica, talc, teniolite, montmorillonite, saponite, hectorite, zirconium phosphate and the like represented by the formula 3MgO.4SiO.H ₂ O.

In the mica group, examples of natural mica include muscovite, soda mica, phlogopite, biotite and sericite. Synthetic mica includes non-swellable mica such as fluorine phlogopite mica ₃ (AlSi ₃ O ₁₀ ) F ₂ , potassium tetrasilicon mica KMg _2.5 Si ₄ O ₁₀ ) F ₂ , and Na tetrasilicic mica NaMg _2.5 ( Si ₄ O ₁₀ ) F ₂ , Na or Li teniolite (Na, Li) Mg ₂ Li (Si ₄ O ₁₀ ) F ₂ , montmorillonite-based Na or Li hectorite (Na, Li) _1/8 Mg ₂ / 5Li ₁ Swellable mica such as _{/ 8} (Si ₄ O ₁₀ ) F ₂ . Synthetic smectite is also useful.

Among the inorganic layered compounds, fluorine-based swellable mica, which is a synthetic inorganic layered compound, is particularly useful. That is, this swellable synthetic mica and swellable viscosity minerals such as montmorillonite, saponite, hectorite, bentonite, etc. have a laminated structure composed of unit crystal lattice layers with a thickness of about 10 to 15 mm, Atomic substitution is significantly greater than other viscous minerals. As a result, the lattice layer is deficient in positive charges, and cations such as Na ⁺ , Ca ²⁺ and Mg ²⁺ are adsorbed between the layers in order to compensate for this. The cations present between these layers are called exchangeable cations and exchange with various cations. In particular, when the cation between the layers is Li ⁺ or Na ⁺ , the bond between the layered crystal lattices is weak because the ionic radius is small, and the layer swells greatly with water. If shear is applied in this state, it will easily cleave and form a stable sol in water. Bentonite and swellable synthetic mica have this tendency and are useful in the present invention, and swellable synthetic mica is particularly preferably used.

  As the shape of the inorganic layered compound, from the viewpoint of diffusion control, the thinner the better, the better the plane size as long as the smoothness of the coated surface and the transmittance of actinic rays are not impaired. Accordingly, the aspect ratio is 20 or more, preferably 100 or more, particularly preferably 200 or more. The aspect ratio is the ratio of the thickness to the major axis of the particle, and can be measured, for example, from a projected view of the particle by a micrograph. The larger the aspect ratio, the greater the effect that can be obtained.

  As for the particle size of the inorganic stratiform compound, the average major axis is 0.3 to 20 μm, preferably 0.5 to 10 μm, particularly preferably 1 to 5 μm. The average thickness of the particles is 0.1 μm or less, preferably 0.05 μm or less, particularly preferably 0.01 μm or less. For example, among inorganic layered compounds, the size of the swellable synthetic mica that is a representative compound is about 1 to 50 nm in thickness and about 1 to 20 μm in surface size.

  When the inorganic layered compound particles having a large aspect ratio are contained in the protective layer, the coating film strength is improved and the permeation of oxygen and moisture can be effectively prevented. Deterioration is prevented, and even when stored for a long time under high-humidity conditions, the storage stability of the planographic printing plate precursor does not deteriorate due to changes in humidity, and the storage stability is excellent.

  It is preferable that content of the inorganic stratiform compound in a protective layer is 5/1-1/100 by mass ratio with respect to the quantity of the binder used for a protective layer. Even when a plurality of inorganic layered compounds are used in combination, the total amount of these inorganic layered compounds is preferably the above-described mass ratio.

  Next, an example of a general dispersion method of the inorganic stratiform compound used for the protective layer will be described. First, 5 to 10 parts by mass of the swellable layered compound mentioned above as a preferred inorganic layered compound is added to 100 parts by mass of water, and the mixture is thoroughly swelled and swollen, and then dispersed by a disperser. Examples of the disperser used here include various mills that disperse mechanically by applying a direct force, a high-speed stirring disperser having a large shearing force, and a disperser that provides high-intensity ultrasonic energy. Specifically, ball mill, sand grinder mill, visco mill, colloid mill, homogenizer, tisol bar, polytron, homomixer, homo blender, ketdy mill, jet agitator, capillary emulsifier, liquid siren, electrostrictive ultrasonic generator, An emulsifying device having a Paulman whistle can be used. A dispersion of 5 to 10% by mass of the inorganic stratiform compound dispersed by the above method is highly viscous or gelled and has very good storage stability. When preparing a protective layer coating solution using this dispersion, it is preferably prepared by diluting with water and stirring sufficiently, and then blending with a binder solution.

  In addition to the inorganic layered compound, known additives such as a surfactant for improving the coating property and a water-soluble plasticizer for improving the physical properties of the film can be added to the protective layer coating solution. Examples of the water-soluble plasticizer include propionamide, cyclohexanediol, glycerin, sorbitol and the like. A water-soluble (meth) acrylic polymer can also be added. Furthermore, known additives for improving the adhesion to the photosensitive layer and the temporal stability of the coating solution may be added to the coating solution.

  The protective layer coating solution thus prepared is applied onto the photosensitive layer provided on the support and dried to form a protective layer. The coating solvent can be appropriately selected in relation to the binder, but when a water-soluble polymer is used, it is preferable to use distilled water or purified water. The method for applying the protective layer is not particularly limited, and a known method such as the method described in US Pat. No. 3,458,311 or Japanese Patent Publication No. 55-49729 can be applied. . Specific examples of the protective layer include blade coating, air knife coating, gravure coating, roll coating coating, spray coating, dip coating, and bar coating.

The coating amount of the protective layer is preferably in the range of 0.05 to 10 g / m ^{2 in} terms of the coating amount after drying. When the inorganic layered compound is contained, 0.1 to 0.5 g / The range of m ² is more preferable, and when the inorganic layered compound is not contained, the range of 0.5 to 5 g / m ² is more preferable.

<Support>
The support used for the lithographic printing plate precursor is not particularly limited as long as it is a dimensionally stable plate-like hydrophilic support. For example, paper, paper laminated with plastic (eg, polyethylene, polypropylene, polystyrene, etc.), metal plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, cellulose diacetate, cellulose triacetate, cellulose propionate) Cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), and paper or plastic films on which the above-mentioned metals are laminated or deposited. Preferable supports include a polyester film and an aluminum plate. Among these, an aluminum plate that has good dimensional stability and is relatively inexpensive is preferable.

  The aluminum plate is a pure aluminum plate, an alloy plate containing aluminum as a main component and containing a trace amount of different elements, or a plastic laminated on a thin film of aluminum or an aluminum alloy. Examples of foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of foreign elements in the alloy is preferably 10% by mass or less. A pure aluminum plate is preferred, but completely pure aluminum is difficult to manufacture in terms of refining technology, so it may contain slightly foreign elements. The composition of the aluminum plate is not specified, and a publicly known material can be used as appropriate.

  The thickness of the support is preferably from 0.1 to 0.6 mm, more preferably from 0.15 to 0.4 mm, and even more preferably from 0.2 to 0.3 mm.

  Prior to using the aluminum plate, it is preferable to perform a surface treatment such as roughening treatment or anodizing treatment. By the surface treatment, it becomes easy to improve hydrophilicity and secure adhesion between the photosensitive layer and the support. Prior to the roughening treatment of the aluminum plate, a degreasing treatment with a surfactant, an organic solvent, an alkaline aqueous solution or the like for removing rolling oil on the surface is performed as desired.

The surface roughening treatment of the aluminum plate is performed by various methods. For example, mechanical surface roughening treatment, electrochemical surface roughening treatment (surface roughening treatment for dissolving the surface electrochemically), chemical treatment, etc. Surface roughening treatment (roughening treatment that chemically selectively dissolves the surface).
As a method for the mechanical surface roughening treatment, a known method such as a ball polishing method, a brush polishing method, a blast polishing method, or a buff polishing method can be used.
Examples of the electrochemical surface roughening treatment include a method in which an alternating current or a direct current is used in an electrolytic solution containing an acid such as hydrochloric acid or nitric acid. Another example is a method using a mixed acid as described in JP-A-54-63902.

  The surface-roughened aluminum plate is subjected to an alkali etching treatment using an aqueous solution of potassium hydroxide, sodium hydroxide or the like, if necessary, further neutralized, and if desired, wear resistant. In order to increase the anodic oxidation treatment.

As the electrolyte used for the anodizing treatment of the aluminum plate, various electrolytes that form a porous oxide film can be used. In general, sulfuric acid, hydrochloric acid, oxalic acid, chromic acid or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of electrolyte.
The conditions for anodizing treatment vary depending on the electrolyte used, and thus cannot be specified in general. In general, however, an electrolyte concentration of 1 to 80% by mass solution, a liquid temperature of 5 to 70 ° C., a current density of 5 to 60 A / d m ² , voltage 1 to 100 V, and electrolysis time 10 seconds to 5 minutes are preferable. The amount of the anodized film formed is preferably from 1.0 to 5.0 g / m ^2, and more preferably 1.5 to 4.0 g / m ^2. Within this range, good printing durability and good scratch resistance of the non-image area of the lithographic printing plate can be obtained.

  As the support, the substrate having the above-mentioned surface treatment and having an anodized film may be used as it is, but for further improvement of adhesiveness with the upper layer, hydrophilicity, resistance to contamination, heat insulation, etc., as necessary. Surfaces immersed in an aqueous solution containing a hydrophilic compound and micropore enlargement treatment, micropore sealing treatment of the anodized film described in JP-A-2001-253181 and JP-A-2001-322365 A hydrophilic treatment or the like can be appropriately selected and performed. Of course, these enlargement processing and sealing processing are not limited to those described above, and any conventionally known method can be performed.

Sealing treatment includes vapor sealing, single treatment with zirconic fluoride, treatment with an aqueous solution containing an inorganic fluorine compound such as treatment with sodium fluoride, vapor sealing with addition of lithium chloride, sealing with hot water. Hole processing is also possible.
Of these, sealing treatment with an aqueous solution containing an inorganic fluorine compound, sealing treatment with water vapor, and sealing treatment with hot water are preferable.

  The hydrophilization treatment is described in the specifications of US Pat. Nos. 2,714,066, 3,181,461, 3,280,734, and 3,902,734. There are such alkali metal silicate methods. In this method, the support is immersed in an aqueous solution such as sodium silicate or electrolytically treated. In addition, the treatment with potassium zirconate fluoride described in JP-B 36-22063, U.S. Pat. Nos. 3,276,868, 4,153,461 and 4,689, And a method of treating with polyvinylphosphonic acid as described in the specification of No. 272.

  When using a support with insufficient surface hydrophilicity, such as a polyester film, it is desirable to apply a hydrophilic layer to make the surface hydrophilic. As the hydrophilic layer, at least one element selected from beryllium, magnesium, aluminum, silicon, titanium, boron, germanium, tin, zirconium, iron, vanadium, antimony, and a transition metal described in JP-A-2001-199175 A hydrophilic layer formed by coating a coating solution containing a colloid of oxide or hydroxide, or organic hydrophilicity obtained by crosslinking or pseudo-crosslinking an organic hydrophilic polymer described in JP-A-2002-79772 A hydrophilic layer having a hydrophilic matrix, a hydrophilic layer having an inorganic hydrophilic matrix obtained by sol-gel conversion comprising hydrolysis, condensation reaction of polyalkoxysilane, titanate, zirconate or aluminate, or a metal oxide A hydrophilic layer made of an inorganic thin film having a surface is preferred. Arbitrariness. Among these, a hydrophilic layer formed by applying a coating solution containing a silicon oxide or a hydroxide colloid is preferable.

  Moreover, when using a polyester film etc. as a support body, it is preferable to provide an antistatic layer on the hydrophilic layer side or the opposite side or both sides of the support body. In the case where the antistatic layer is provided between the support and the hydrophilic layer, it also contributes to improving the adhesion with the hydrophilic layer. As the antistatic layer, a polymer layer in which metal oxide fine particles or a matting agent are dispersed as described in JP-A-2002-79772 can be used.

The support preferably has a center line average roughness of 0.10 to 1.2 μm. Within this range, good adhesion to the photosensitive layer, good printing durability and good stain resistance can be obtained.
The color density of the support is preferably 0.15 to 0.65 as the reflection density value. Within this range, good image formability by preventing halation during image exposure and good plate inspection after development can be obtained.

<Undercoat layer>
In the lithographic printing plate precursor, it is preferable to provide an undercoat layer of a compound containing a polymerizable group on a support. When an undercoat layer is used, the photosensitive layer is provided on the undercoat layer. The undercoat layer reinforces the adhesion between the support and the photosensitive layer in the exposed area, and easily peels the photosensitive layer from the support in the unexposed area, thereby improving the developability.
As the undercoat layer, specifically, a silane coupling agent having an addition-polymerizable ethylenic double bond reactive group described in JP-A-10-282679, JP-A-2-304441. The phosphorus compound etc. which have the ethylenic double bond reactive group of description are mentioned suitably. Particularly preferable compounds include compounds having a polymerizable group such as a methacryl group or an allyl group and a support adsorbing group such as a sulfonic acid group, a phosphoric acid group, or a phosphoric acid ester. A compound having a hydrophilicity-imparting group such as an ethylene oxide group in addition to the polymerizable group and the support-adsorbing group can also be exemplified as a suitable compound.
The coating amount (solid content) of the undercoat layer is preferably from 0.1-100 mg / m ^2, and more preferably 1 to 30 mg / m ^2.

<Back coat layer>
After the surface treatment is performed on the support or after the undercoat layer is formed, a back coat can be provided on the back surface of the support, if necessary.
Examples of the back coat include hydrolysis and polycondensation of organic polymer compounds described in JP-A-5-45885, organometallic compounds or inorganic metal compounds described in JP-A-6-35174. A coating layer made of a metal oxide obtained in this manner is preferred. Among them, it is inexpensive to use a silicon alkoxy compound such as Si (OCH ₃ ) ₄ , Si (OC ₂ H ₅ ) ₄ , Si (OC ₃ H ₇ ) ₄ , Si (OC ₄ H ₉ ) _4. It is preferable in terms of easy availability.

<Exposure>
In the plate making method of the present invention, the lithographic printing plate precursor is exposed imagewise by exposure through a transparent original image having a line image, a halftone dot image or the like, or by laser scanning exposure with digital data. When a laser is used, it is preferable to perform imagewise scanning exposure according to digital data. In order to shorten the exposure time, it is preferable to use a multi-beam laser device.
These lasers are used by being mounted on a so-called platesetter that performs imagewise exposure under computer control.

  In the present invention, after the exposure step, a heat treatment step (preheating) is provided between the exposure step and the development step. This heat treatment has the effect of improving the printing durability and further improving the uniformity of the image curing degree within the plate surface, and the conditions can be appropriately set within the range where these effects are present. Examples of the heating means include a conventional convection oven, an IR irradiation device, an IR laser, a microwave device, a Wisconsin oven, and the like. Specifically, it can be carried out by holding the plate surface temperature in the range of 70 to 150 ° C. for 1 second to 5 minutes. Preferably, the temperature is 80 ° C to 140 ° C for 5 to 1 minute, more preferably 90 ° C to 130 ° C for 10 to 30 seconds. This range is preferable in that the above effect can be obtained efficiently and there is no adverse effect such as deformation of the printing plate due to heat. A cooling zone is provided after this heat treatment step. A plurality of fans for cooling the plate surface may be provided in the cooling zone.

  At this time, it is preferable that the heat treatment means used in the heat treatment step, the cooling means, and the developing device used in the development treatment step are connected to each other and automatically continuously processed. Specifically, it is a plate making line in which a plate setter and a developing device are coupled by a conveying means such as a conveyor. A heat treatment unit may be provided between the plate setter and the developing device, and the heating unit and the developing device may be integrated.

  When the printing plate to be used is easily affected by ambient light in the work environment, it is preferable that the plate making line is shielded by a filter or a cover.

After finishing the development process and forming an image as described above, the entire surface may be exposed with an actinic ray such as ultraviolet light to accelerate the curing of the image portion. Examples of the light source for the entire surface exposure include a carbon arc lamp, a mercury lamp, a gallium lamp, a metal halide lamp, a xenon lamp, a tungsten lamp, and various laser lights. Further, in order to obtain a sufficient printing durability, the overall exposure is preferably at least 10 mJ / cm ² or more, more preferably 100 mJ / cm ² or more.

  Furthermore, heating may be performed simultaneously with the entire surface exposure, and further improvement in printing durability is recognized by heating. Examples of the heating device include a conventional convection oven, an IR irradiation device, an IR laser, a microwave device, a Wisconsin oven, and the like. At this time, the plate surface temperature is preferably 30 ° C to 150 ° C, more preferably 35 ° C to 130 ° C, and still more preferably 40 ° C to 120 ° C.

2. Platemaking evaluation (development evaluation)
The resulting lithographic printing plate precursor A was loaded on a Violet semiconductor laser setter Vx9600 (InGaN semiconductor laser 405 nm ± 10 nm emission / output 30 mW) manufactured by FUJIFILM Electronic Imaging Ltd, with an exposure amount of 90 μJ / cm ² and a resolution of 96 lpmm, A 50% flat mesh was drawn.

Next, the configuration of the transport roller pair 318 will be described. The conveyance roller pair 318 is formed of a tube-shaped metal core made of metal and a roller surface around the metal core with rubber. In the present embodiment, the hardness of the roller surface is preferably 20 to 40 degrees, and the roughness of the roller surface is preferably 8.0 μm to 15.0 μm at the maximum height (Ry). The present inventor has paid attention to the fact that when the developer attached to the lithographic printing plate precursor is squeezed out, it is effective to have a dense roller surface and to reduce the altitude. Specifically, the clearance between the roller surface and the lithographic printing plate can be reduced by setting the roughness of the roller surface to a maximum height (Ry) of 8.0 μm to 15.0 μm. Further, by setting the hardness of the roller surface to 20 to 40 degrees, the rubber forming the roller surface also enters between the nip surface of the conveying roller pair 318 and the lithographic printing plate precursor so that a gap is generated. Can be suppressed. Here, the maximum height of roughness (Ry) means that only the reference length is extracted from the roughness curve in the direction of the average line, and the distance between the peak line and the valley bottom line of the extracted part is determined by the rough height. A value measured in the direction of the vertical magnification of the vertical curve, for example, as defined in JIS B0601-1994.
Further, it is preferable to use a metal core having rigidity that does not bend due to the nip pressure of the conveying roller pair 318. Furthermore, in order to improve the drawability of the central portion, a crown roller having a roller diameter at the central portion larger than a roller diameter at the end portion may be used.
The material of the rubber constituting the roller surface is preferably one having chemical resistance and durability.
The nip pressure of the conveying roller pair 318 is preferably 0.5 to 2.0 kg / cm ² . As a pressure measuring device for measuring the nip pressure, a tactile pressure measuring device manufactured by Nitta Corporation was used.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these.
In the automatic developing apparatus shown in FIG. 1, 20 L of the following developer was put and heated to 30 ° C. for processing.
Developer: (A) Aqueous solution 1 was prepared. The unit is [g].
The pH of the aqueous solution 1 was 4.5.
6906 g of water
Amphoteric surfactant PIONIN C-157-K N-Lauryl Dimethyl Betain (manufactured by Takemoto Yushi Co., Ltd.) See Table 1 40% aqueous solution 2500 g
Gum arabic 150 g
Enzyme-modified potato starch 400 g
Monobasic ammonium phosphate 24 g
Phosphoric acid (85% aqueous solution) 10 g
EDTA-4-sodium salt 10 g

[Preparation of lithographic printing plate precursor type I]
Preparation of support body An aluminum plate (material JIS A1050) having a thickness of 0.3 mm was immersed in 10% by weight sodium hydroxide at 60 ° C. for 25 seconds, etched, washed with running water, and then neutralized and washed with 20% by weight nitric acid. Then, it was washed with water. This was subjected to an electrolytic surface roughening treatment in a 1% by mass nitric acid aqueous solution using a sinusoidal alternating waveform current at an anode time electricity of 300 coulomb / dm ² . Subsequently, after dipping in a 1% by mass aqueous sodium hydroxide solution at 40 ° C. for 5 seconds and then in a 30% by mass sulfuric acid aqueous solution and desmutting at 60 ° C. for 40 seconds, the current density in a 20% by mass sulfuric acid aqueous solution was 2A / current density. Anodization was performed for 2 minutes so that the thickness of the anodized film was 2.7 g / m ² under the condition of dm ² . Then, it processed at 20 degreeC for 10 second with 1 mass% of sodium silicate aqueous solution. The center line average roughness (Ra) of the support thus obtained was measured using a needle having a diameter of 2 μm and found to be 0.25 μm (Ra indication according to JIS B0601).

Furthermore, after applying the following undercoat liquid (1) with a bar, it was oven-dried at 80 ° C. for 10 seconds to apply a dry coating amount of 10 mg / m ² , and a support having an undercoat layer used in the following experiments. Produced.

Undercoat liquid (1)
・ The following polymer compound (1) 0.017 g
・ Methanol 9.00 g
・ Water 1.00g

A photosensitive layer coating solution 1 having the following composition was bar coated on the aluminum support provided with the undercoat layer, followed by oven drying at 70 ° C. for 60 seconds to form a photosensitive layer having a dry coating amount of 1.1 g / m ^2. A protective layer coating solution 1 having the following composition is formed on the coating layer using a bar so that the dry coating amount is 0.75 g / m ^2, and then dried at 125 ° C. for 70 seconds for protection. A layer was formed to prepare a lithographic printing plate precursor type I series.

(Photosensitive layer coating solution 1)
-Specific binder polymer of the present invention (see Table 2)
0.54g
-Compound (M-1) having an ethylenically unsaturated bond 0.48 g
・ Radical polymerization initiator (I-1) 0.08g
Sensitizing dye (D-1) 0.06g
・ Chain transfer agent (S-2) 0.07g
・ 0.40 g of ε-phthalocyanine pigment dispersion
[Pigment: 15 parts by mass, Allyl methacrylate / methacrylic acid (80/20) copolymer as a dispersant: 10 parts by mass, Cyclohexanone / methoxypropyl acetate / 1-methoxy-2-propanol = 15 parts by mass / 20 parts as a solvent Parts / 40 parts by mass]
・ Thermal polymerization inhibitor 0.01g
(N-nitrosophenylhydroxylamine aluminum salt)
・ Fluorine-based surfactant (F-1) 0.001 g
・ Polyoxyethylene-polyoxypropylene condensate 0.04g
(Asahi Denka Kogyo Co., Ltd., Pluronic L44)
・ Tetraethylammonium chloride 0.01g
・ 3.5 g of 1-methoxy-2-propanol
・ Methyl ethyl ketone 8.0g

(Protective layer coating solution (2))
・ The following mica dispersion (1): 13.00 g
Polyvinyl alcohol (saponification degree 98 mol%, polymerization degree 500)
1.30g
-Sodium 2-ethylhexyl sulfosuccinate 0.20 g
-Poly (vinyl pyrrolidone / vinyl acetate (1/1)) molecular weight 70,000
0.050g
・ Surfactant (Emalex 710; manufactured by Nippon Emulsion Co., Ltd.)
0.050g
・ Water 133.00g

(Preparation of mica dispersion (1))
To 368 g of water, 32 g of synthetic mica (“Somasif ME-100” manufactured by Co-op Chemical Co., Ltd., aspect ratio: 1000 or more) is added and dispersed using an homogenizer until the average particle size (laser scattering method) is 0.5 μm. As a result, a mica dispersion (1) was obtained.

<Examples and comparative examples>
For the development squeeze rollers of Examples and Comparative Examples shown in the following table, the amount of residual developer on the planographic printing plate and the stickiness of the plate surface were evaluated. A roller length of 870 mm was used. In the following measurement, a JIS A rubber hardness tester was used for rubber hardness measurement. For the rubber hardness, a constant pressure loader was used in order to eliminate the variation in individual differences measured by manual measurement. For surface roughness measurement, Surfcom 575A manufactured by Tokyo Seimitsu Co., Ltd. was used. Those with no stickiness were indicated with “◯”, those with a little stickiness were indicated with “Δ”, and those with stickiness were indicated with “x”.

  As a result of the measurement, the developing diaphragm roller has a roller surface hardness of 20 to 40 degrees, and the roller surface roughness is 8.0 μm to 15.0 μm at the maximum height (Ry). It was found that the stickiness of the lithographic printing plate after treatment can be suppressed.

1 is a configuration diagram of an automatic developing device according to a first embodiment of the present invention. It is a longitudinal cross-sectional view which shows the structure of the photosensitive lithographic printing plate precursor.

Explanation of symbols

2 Support 4 Photosensitive layer (image recording layer)
5 Overcoat layer (surface protective film)
10 PS plate (lithographic printing plate precursor)
DESCRIPTION OF SYMBOLS 100 Automatic developing apparatus 200 Pre-processing part 300 Development processing part 318 Development aperture roller 400 Drying part

Claims (8)

After image exposure of a lithographic printing plate precursor having an image recording layer on a support, the lithographic printing plate precursor is immersed in a developer to develop the image recording layer, thereby removing non-image areas and desensitizing A processing method for a lithographic printing plate precursor
A processing method for a lithographic printing plate precursor using a developing squeeze roller having a roller surface hardness of 20 to 40 degrees and a roller surface roughness of 8.0 μm to 15.0 μm at the maximum height (Ry).   The lithographic printing plate precursor as claimed in claim 1, wherein the component of the processing solution for simultaneously performing the development processing and the desensitization processing contains 3 to 20 mass% of a surfactant and has a pH of 2 to 10. Processing method.   The processing method of the lithographic printing plate precursor as claimed in claim 1 or 2, wherein the component of the processing solution for simultaneously performing the development processing and the desensitizing processing contains 1 to 10% by mass of a water-soluble resin.   The processing method according to any one of claims 1 to 3, wherein the photosensitive layer of the lithographic printing plate precursor contains a hydrophobic binder polymer, a polymerization initiator, and a polymerizable compound. An lithographic printing plate precursor automatic developing device for developing a lithographic printing plate precursor image-exposed on an image recording layer on a support,
The lithographic printing plate transported from the development processing unit, comprising a development processing unit that immerses the lithographic printing plate precursor in a developer, develops an image recording layer of the lithographic printing plate precursor, and performs a desensitization process A pair of development squeezing rollers that rotate relative to each other while sandwiching the original plate are provided, and the hardness of the roller surface of the development squeezing roller is 20 degrees to 40 degrees, and the roughness of the roller surface is the maximum height (Ry). An automatic development apparatus for a lithographic printing plate precursor using a development squeezing roller of 8.0 μm to 15.0 μm.   The lithographic printing plate precursor as claimed in claim 5, wherein the main component of the processing solution for simultaneously performing the development treatment and the desensitization treatment contains 3 to 20 mass% of a surfactant and has a pH of 2 to 10. Automatic developing device.   7. The lithographic printing plate precursor automatic developing apparatus for simultaneously performing development processing and desensitization processing according to claim 5 or 6, wherein the component of the processing liquid contains 1 to 10% by mass of a water-soluble resin.   The lithographic printing plate precursor as claimed in any one of claims 5 to 7, wherein the photosensitive layer of the lithographic printing plate precursor comprises a hydrophobic binder polymer, a polymerization initiator and a polymerizable compound. apparatus.

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