JP2009216926A - Automatic developing device for planographic printing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an automatic developing device for a planographic printing plate, the device capable of preparing a high-quality planographic printing plate. <P>SOLUTION: The automatic developing device 2 for a planographic printing plate brings a planographic printing plate 4 having an image-exposed image recording layer on a support body into contact with a developing solution so as to remove an unnecessary part of the image recording layer, and the device is equipped with: a rubbing member 24 rubbing the planographic printing plate 4 in contact with the developer solution; a squeezing roller 26 disposed in a downstream of the rubbing member 24 and squeezing the developer solution depositing on the planographic printing plate 4; and a pressurizing roller 29 disposed between the rubbing member 24 and the squeezing roller 26 and pressurizing the planographic printing plate 4. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an automatic developing apparatus for producing a lithographic printing plate.

  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. The image recording layer is typically provided by being applied to the surface of a grained support (see, for example, Patent Document 1).

  Then, in a conventional lithographic printing plate preparation process, the lithographic printing plate precursor is exposed through an original image such as a lith film and then subjected to development processing. In recent years, digitization techniques for electronically processing, storing, and outputting image information by a computer have become widespread, and various new image output methods corresponding to such digitization techniques have been put into practical use. It has become like this. Along with this, digitized image information is carried on high-convergence radiation such as laser light, and the lithographic printing plate precursor is scanned and exposed with the light, so that the lithographic printing plate can be directly formed without using a lithographic film. Computer-to-plate technology for exposure is also known.

  In the development processing step, the exposed lithographic printing plate precursor is first treated with a developer to leave a portion that becomes an image portion of the image recording layer, and other unnecessary image recording layers are dissolved and removed by the developer. In the portion from which the image recording layer has been removed, the hydrophilic support surface is exposed and a non-image portion is formed. Generally, an alkaline developer having a pH of 10 or higher is used as the developer. A method of rubbing the surface of a lithographic printing plate precursor in a developer is known in order to promote the removal of unnecessary image recording layers and reduce the time required for development processing (see, for example, Patent Document 1).

The lithographic printing plate on which the image portion and the non-image portion are formed as described above is then treated with a gum solution mainly composed of a hydrophilic resin by flowing a developer in a water-washing bath. Here, if a large amount of the developer is mixed in the subsequent washing bath, the replacement frequency of the washing solution increases. Therefore, conventionally, the developer attached to the lithographic printing plate is pressed against the lithographic printing plate. This squeezing roller is used to remove the water before the washing bath (see, for example, Patent Document 2).
Japanese Patent Laid-Open No. 10-198044 JP 2000-112143 A

  In recent years, from the viewpoint of environment and safety, use of a developing solution closer to the neutral range and reduction of waste liquid have been demanded. However, reducing the alkali level of the developer gives a large load to the development process. For example, an unnecessary image recording layer was easily dissolved and removed by an alkaline developer having a pH of 10 or more, but not easily removed by a low alkaline developer, particularly near the grained support surface. Then, it is difficult to remove due to the grain of the support surface. Then, the remaining unnecessary image recording layer becomes a residue on the plate, causing poor appearance and eventually smearing during printing. In some cases, the remaining unnecessary image recording layer contaminates the inside of the developing apparatus, and the degree of time and labor required for maintenance has increased.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide an automatic developing apparatus for a lithographic printing plate that can produce a high-quality lithographic printing plate.

In order to solve the above-mentioned problems, the invention of an automatic developing device for a lithographic printing plate according to claim 1 is characterized in that the lithographic printing plate on which the image recording layer on the support is image-exposed is brought into contact with the developer to An automatic development apparatus for a lithographic printing plate that removes unnecessary portions, the rubbing member that rubs the lithographic printing plate in contact with the developer, and the rubbing member that is provided downstream of the rubbing member and adheres to the lithographic printing plate A squeezing roller for squeezing the developer, and a pressure roller that is disposed between the rubbing member and the squeezing roller and presses the lithographic printing plate.
The invention described in claim 2 is characterized in that the lithographic printing plate is pressed by the pressure roller while the lithographic printing plate is immersed in the developer.
The invention described in claim 3 is characterized in that the main component of the developer contains 3 to 20% by mass of a surfactant and the pH is 4 to 9.5.
The invention described in claim 4 is characterized in that the developer component contains 1 to 10% by mass of a water-soluble resin.

According to the present invention, by providing a pressure roller between the rubbing member and the squeezing roller, the rubber layer of the roller is deformed by the nip pressure, and at the same time, the time for the image recording layer to contact the roller surface becomes longer. Unnecessary portions of the image recording layer are easily removed due to fine shear stress. The squeezing roller means a roller in which the developer of the lithographic printing plate is squeezed after the lithographic printing plate passes through the roller. On the other hand, the pressure roller means a roller in a position where the developer is supplied to the lithographic printing plate by spraying or the like even after the lithographic printing plate passes through the roller. The pressure roller is a pair of rollers, and a load of 1 to 10 kg is applied to each side of the upper roller by a spring or a screw. As a result, a lithographic printing plate having a certain quality can be produced without causing the problem of contamination or residue of the automatic developing apparatus.
Further, if the lithographic printing plate is pressed with a pressure roller while the lithographic printing plate is immersed in the developer, the contact time between the lithographic printing plate and the developer becomes longer, and unnecessary portions of the image recording layer are formed. Can be more easily removed.
Further, if the pH of the developer is lowered to 4 to 9.5, it contributes to environmental protection and is safe and easy to handle. In addition, the pH change with time of carbon dioxide in the atmosphere is large in a developer having a high pH of 10 or more, whereas the developer with low pH of 4 to 9.5 has little change in pH with time. There is no need to consider developer fatigue. However, on the other hand, it is not easily removed with a low alkali developer, and is particularly difficult to remove due to the grain of the support surface near the boundary with the grained support surface. Then, the remaining unnecessary image recording layer becomes a residue on the plate, causing poor appearance and eventually smearing during printing. In some cases, the remaining unnecessary image recording layer contaminates the inside of the developing device, increasing the degree of time and labor required for maintenance. For this reason, the above-described pressure roller is installed. However, by adding 3 to 20% by mass of the surfactant of the developer from the developer, the decrease in developability due to the low pH can be compensated. it can.
Moreover, a non-image-part protective film can be formed by including a water-soluble resin in the developer. This eliminates the need for water washing and gum treatment after development, thereby reducing the amount of waste liquid. Further, it is possible to reduce the size of the developing device and facilitate maintenance of the developing device.

Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.
<Embodiment 1>
FIG. 1 is a configuration diagram of an automatic developing apparatus according to Embodiment 1 of the present invention.
As shown in FIG. 1, the automatic developing device 2 develops a photosensitive lithographic printing plate (hereinafter referred to as “PS plate”) 4 and develops a developing unit 6 that also performs gumming, and dries the developed PS plate 4. And a drying unit 10 for performing.

  The PS plate 4 is exposed to an exposure device (not shown) and then supplied to the automatic developing device 2. In this exposure apparatus, the PS plate 4 is exposed through a transparent original image having a line image, a halftone dot image, or the like, or is exposed imagewise by laser beam 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, laser beams, and the like. Examples of the semiconductor laser include an ultraviolet semiconductor laser that emits light having a wavelength of 250 to 420 nm, an argon ion laser that emits visible light, and an FD-YAG laser. Among these, from the viewpoint of simplification of plate making, a laser that emits infrared rays or ultraviolet rays that can be operated under white light or yellow light is preferable.

  The exposed PS plate 4 is inserted into the automatic developing device 2 from the insertion port 14 formed in the side plate 12 and is conveyed to the developing unit 6 by the carry-in roller 16. The insertion port 14 is provided with a rubber blade 18, and the insertion port 14 is closed by the rubber blade 18 except when the PS plate 4 is inserted.

  The developing unit 6 is provided with a transport roller 22, a brush roller (rubbing member) 24, a pressure roller 29, and a squeeze roller 26 in order from the upstream side along the transport direction of the PS plate 4. A backup roller may be provided at an appropriate position between these rollers. The PS plate 4 is conveyed substantially horizontally between the conveying roller 22, the brush roller 24, the pressure roller 29, and the squeezing roller 26.

  The developing member 6 sprays the developer 58 in the developing tank 20 toward the PS plate 4 at appropriate positions among the conveying roller 22, the brush roller 24, the pressure roller 29, and the squeezing roller 26. Is provided. In the illustrated example, ejection members 34 c are provided between the conveying roller 22 and the brush roller 24, between the brush roller 24 and the pressure roller 29, and between the pressure roller 29 and the squeezing roller 26, respectively.

  The PS plate 4 is sprayed with a developing solution while being conveyed by the conveying roller 22 or the like, leaving a portion that becomes an image portion of the image recording layer, and other unnecessary image recording layers are dissolved and removed by the developing solution. By rubbing with the brush roller 24, removal of unnecessary image recording layers is promoted, and the time required for development processing is shortened.

  On the downstream side of the brush roller 24, the developer attached to the PS plate 4 is removed by a pair of squeezing rollers 26 pressed and urged against the PS plate 4, but in the present invention, the brush roller 24, the squeezing roller 26, Further, a pair of pressure rollers 29 that are pressed against the PS plate 4 are provided. Pressure is applied by the pressure roller 29, and then the pressure is reduced by the squeezing roller 26. The rubber layer of the roller is deformed by nip pressure (a load of 2 kg weight is applied to both ends of the upper roll by the spring. The load applied to both ends of the upper roller is preferably 1.5 to 5 kg weight), and PS The time during which the image recording layer of the plate 4 is in contact with the roller surface is lengthened, and at the same time, the unnecessary image recording layer is easily removed by the fine shear stress. The developed PS plate 4 is conveyed to the next drying 10 by the squeezing roller 26.

  The drying unit 10 is provided with a guide roller 36 and a pair of skewer rollers 38 in order from the upstream side along the conveying direction of the PS plate 4. The drying unit 10 is provided with drying means (not shown) such as hot air supply means and heat generation means. The drying unit 10 is provided with a discharge port 40, and the PS plate 4 dried by the drying means is discharged from the discharge port 40.

  In the automatic developing device 2 having the above-described configuration, the rubber blade 62 is arranged in contact with the carry-in roller 16 at the entrance, and the developing unit 6 is substantially airtight with respect to the external atmosphere, so that outside air does not flow in. It is like that. Further, a shutter 44 is provided in a passage 46 between the drying unit 10 and the developing unit 6, and the passage 46 is closed by the shutter 44 when the PS plate 4 does not pass through the passage 46. Therefore, the developing unit 6 has a hermetically sealed structure in which air flows in slightly when the PS plate 4 passes, but is substantially airtight and hardly receives air.

  Although the automatic developing device 2 described above is for processing the developer 58 charged in the developing tank 20 by pumping it up with a circulation pump and spraying it from the injection member 34c, the present invention is not limited to this. For example, a substantially unused developer 58 may be supplied and processed for each plate as needed. FIG. 2 shows another modified example in which the PS plate 4 is processed by being immersed in a developing solution in the developing tank 20.

  In the automatic developing device 2 ′ shown in FIG. 2, a conveying roller 22, a brush roller 24, a pair of pressure rollers 29, and a pair of squeezing rollers are arranged in the developing unit 6 in order from the upstream side along the conveying direction of the PS plate 4. 26 is provided. The brush roller 24 and the pair of pressure rollers 29 are provided at positions soaking in the developer 58 in the developing tank 20. Thus, by immersing a pair of pressure rollers in the developer, it takes a long time to contact the developer, which is preferable for removing unexposed portions. As for the squeeze roller 26, the contact portion with the PS plate 4 only needs to be above the liquid level, and the position thereof is not particularly limited.

  The PS plate 4 is submerged in the developing tank 20 in the process of being conveyed by the conveying roller 22 and the like, and is immersed in the developer 58 in the developing tank 20 to leave a portion that becomes an image portion of the image recording layer, and the other unnecessary. A new image recording layer is dissolved and removed by a developer. Also in the automatic developing device 2 ′ of this modification, a pair of pressure rollers 29 are provided between the brush roller 24 and the squeezing roller 26, and are pressed by the pressure roller 29, and then squeezed by the squeezing roller 26. It is done. The rubber layer of the roller is deformed by the nip pressure (a load of 4 kg weight is applied to both ends of the upper roll by a screw. The load applied to both ends of the upper roller is preferably 1.5 to 5 kg weight), and PS At the same time that the image recording layer of the plate 4 is in contact with the roller surface, an unnecessary image recording layer is easily removed due to the fine shear stress.

  In the automatic developing device 2 ′ according to this modification, the pressure roller 29 is immersed in the developer 58 in the developer tank 20, so that the contact time between the PS plate 4 and the developer is increased, and an unnecessary image is obtained. The recording layer is more easily removed. Further, since the brush roller 24 that rubs the PS plate 4 to promote the dissolution of unnecessary image recording layers is immersed in the developer 58 in the developer tank 20, the developer is prevented from being scattered, and maintenance such as cleaning is performed. Such troubles are reduced.

  In the automatic developing device 2 ′ of this modification, a box-shaped shielding lid 60 is provided integrally with the tank wall of the developing tank 20. The bottom wall of the shielding lid 60 is formed so as to leave a slight gap between the liquid surface and the upper outer peripheral surface of the transport roller 22, the brush roller 24, and the pressure roller 29 exposed from the liquid surface. Since the shielding lid 60 is box-shaped, an airtight space is defined in the upper part of the developing tank 20, and the amount of air in the developing unit 6 is reduced as much as possible. Further, since the shielding lid 60 is provided, the contact area between the developer and air is reduced as much as possible.

  The developing tank 20 is connected with a first circulation pipe 80 for the developer. In the first circulation pipe 80, a developer circulation pump 71, a conductivity sensor 73, and a filter (not shown) are provided. The developer circulation pump 71 sucks the developer 58 in the developer tank 20 from the suction hole at the bottom of the developer tank 20 into the first circulation pipe 80 and circulates through the first circulation pipe 80. It is discharged into the developing tank 20. The filter filters the developer flowing in the first circulation pipe 80. The conductivity sensor 73 measures the conductivity of the developer flowing in the first circulation pipe 80.

  The developing unit 6 includes a second circulation pipe 90, a developer storage tank 55 connected to the second circulation pipe 90, and a developer supply pump 74 interposed in the second circulation pipe 90. The developer that is provided and overflows from the developing tank 20 is returned to the developer storage tank 55 via the second circulation pipe 90.

  More specifically, a pair of second circulation pipes 90 and 90 a for replenishing the developer 58 is provided in the vicinity of the developing tank 20. The second circulation pipe 90 for the developer 58 is connected to the external tank 55 at the other end (lower end in FIG. 2), and a developer supply pump 74 is provided in the pipe. The developer supply pump 74 measures and supplies the developer 58 from the external tank 55 to the developer tank 20. That is, the second circulation pipe 90, the developer supply pump 74, and the external tank 55 constitute a developer circulation means.

  The developer supply pump 74 includes a control ROM and a RAM (corresponding to a first storage means and a second storage means) 51 in which developer replenishment conditions and the like are stored based on the plate detection sensor 27 and the time measuring unit 52, and It is controlled by a control device (corresponding to first to fourth control means) 50 provided with a time measuring unit 52. That is, the control device 50 controls the developer supply pump 74 based on a signal from the plate detection sensor 27 that can measure whether or not the plate has been conveyed and the plate area of the conveyed plate. Replenishment (circulation) is performed based on the replenishment conditions stored in the control ROM and RAM 51 of the developer set in accordance with the actual operating conditions of the automatic developing device 2. As a result, the control device 50 replenishes the developer 58 in an amount corresponding to the replenishment condition from the developer storage tank 55, for example, for each process of one plate. Here, the replenishment of processing may not be performed for each plate but may be configured by replenishing after a plurality of plates have passed. In addition, 98 is a display device that visually informs various necessary information, and 99 is an alarm device that informs by hearing.

  In the automatic developing apparatus 2 ′, as described above, the PS plate 4 is immersed in the developing solution 58 and rubbed by the brush roller 24 to prevent the developing solution 58 from being scattered. It has been avoided. Here, when rubbing with the brush roller 24 in the state of being immersed in the developer 58, the brush roller 24 is immersed in the developer 58 for more than 1/3 of the diameter from the viewpoint of scattering of the solution. The state is preferably, more preferably half or more is immersed.

  The rubbing process with the brush roller 24 is highly effective when it is performed after being immersed in the developer 58 and after a certain period of time. Therefore, it is possible to effectively remove the photosensitive layer by preliminarily dipping in the developer 58 before performing the rubbing operation. According to the experiment, the elapsed time is 2 seconds or more after the part subjected to the removal operation is immersed in the liquid or wet with the liquid from the spray, more preferably 5 seconds or more, and further 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 58, the photosensitive layer of the PS plate can be brought into contact with the developer 58 using a spray tube S1 or the like. In this case, the developer in the external tank may be sprayed or a fresh developer prepared in another tank may be used. Since it takes a long time until the photosensitive layer is brought into contact with the developer 58 and then rubbed in the developer 58, the development can be performed more effectively. Further, by bringing the developer 58 into contact with the developer 58, it is possible to appropriately shorten the time from the immersion in the developer 58 to the scraping. Further, in order to promote the penetration of the solution, a method of vibrating the PS plate 4 in a state where it is in contact with the developer 58 can be appropriately used.

  Therefore, if it is tsec after dipping in the developer 58 until the PS plate 4 comes out of the developer 58, the rubbing treatment with the rubbing material 24 is preferably performed after t / 2 sec. . Therefore, it is desirable to perform development in the middle or the latter half of the developing tank 20. Of course, the rubbing treatment can be performed in the first half of the developing tank if the developing tank 20 is lengthened or the conveying speed is slowed to increase the time of immersion in the developer 58. In order to always provide a stable development process, the rubbing process by the brush roller 24 is performed in the middle or the latter half.

  Now, after developing using the brush roller 24, the PS plate 4 exits the developer 58. At this time, although depending on the usage situation, when the developer 58 becomes fatigued, depending on the situation, it becomes a situation where debris is likely to adhere. Even in such a case, the developer 58 in the developer storage tank 55 having a lower degree of fatigue than the developer 58 used during the dipping process is directly discharged onto the PS plate 4 by the spray pipe S2, so that the PS plate 4 is discharged. Foreign matter such as adhering debris can be removed.

  As described above, the removal of debris by the spray is remarkable when the degree of fatigue of the developer 58 in the developing tank 20 becomes high. A particularly fine filter can be used as appropriate for the circulation system discharged from the spray pipe S2. In this case, a clean PS plate 4 can be obtained only in the treatment bath, and the steps after the treatment bath can be omitted as appropriate.

Thus, after processing with only one bath, the drying unit 10 is provided, and the plate that has been desensitized simultaneously with development in the first bath is dried in the drying unit 10. In this way, when the treatment is completed with only one bath, the apparatus cost can be reduced and at the same time, the space can be saved.
Moreover, since the developing solution 58 is circulated in the external tank 55, the level of the developing solution can always be maintained at a constant level, and the developing process is stabilized.
In addition, in the conventional apparatus, a new replenisher is replenished, and the overflow portion overflows and is discarded, so that even a developer having a developing ability is partially discarded as a waste solution. By making it circulate, the developing ability of the developer can be used 100%.

  The rubbing member may be any member as long as it can rub the image recording surface of the PS plate 4 original plate. In particular, a member capable of rubbing the image recording surface by rotating around the rotation axis (for example, a known member) Channel brushes, twisting brushes, implantation brushes, carpet brushes, and Morton rollers).

  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 disclosed in JP-A-10-198044 is covered with a cylindrical sliding contact material made of a fiber knitted fabric, and the end on the mounting side is tightened. it can.

  The rotational speed of the brush roller 24 is preferably as fast as possible in order to improve the removability of the image recording layer in the non-exposed portion of the PS plate 4 original plate, but the durability of the automatic developing device, the manufacturing cost, and the developer 58 From the viewpoint of scattering and damage of the exposed portion of the PS plate 4 original plate, 30 to 1000 rpm, more preferably 50 to 500 rpm is preferable.

  The number of the brush rollers 24 may be one or more, and may be plural. In the case of two or more, one or more may be rotated in a direction opposite to the processing direction of the PS plate 4 original plate. Further, when a rotating rubbing member is used, the development processing may be performed while swinging the rubbing member in the direction of the rotation axis. By swinging the rubbing member in the rotation axis direction, the non-image part of the PS plate 4 original plate can be removed more effectively, and a higher quality PS plate 4 can be produced.

  As the material of the brush, 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, and nylon nylon 6.6, nylon 6.10, 6.12, nylon 12, polybutylene terephthalate (PBT), and polypropylene are more preferable. It is done. 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 4 original plate 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, by providing the pressure roller 29 between the brush roller 24 and the squeezing roller 26, the time for the image recording layer to contact the roller surface becomes long, The rubber layer of the roll is deformed by the nip pressure, and an unnecessary image recording layer is easily removed by a fine shear stress at that time. As a result, a lithographic printing plate having a certain quality can be produced without causing the problem of contamination or residue of the automatic developing apparatus.
Further, if the lithographic printing plate is pressed with the pressure roller 29 in a state where the lithographic printing plate is immersed in the developer 58, the contact time between the lithographic printing plate and the developer 58 is increased, and unnecessary image recording is performed. The layer is more easily removed.

<Embodiment 2>
FIG. 3 is a block diagram of an automatic developing apparatus according to Embodiment 2 of the present invention. The reference numerals common to the automatic developing device 2 (FIG. 1) according to the first embodiment and the automatic developing device 2 ′ (FIG. 2) according to the modified example show the same functions, and thus the duplicated explanation is omitted.

  In FIG. 3, the developing unit 6 is basically the same as FIG. The difference is that a pre-heating (pre-heating) part and a pre-water washing (pre-water washing) part are provided upstream of the developing part 6. The preheating unit is installed on the upstream side in the transport direction of the developing unit 6 and has a function of maintaining the specified PS plate surface temperature for a specified time while transporting the PS plate 4. The pre-washing unit is installed on the upstream side in the transport direction of the developing unit 6 and on the downstream side in the transport direction of the pre-heating unit, and the PS plate surface is washed with rinsing water while transporting the PS plate 4 to remove the protective layer on the photosensitive layer. It has the function of cooling and removing it. The PS plate 4 that has passed through the pre-water washing section is automatically conveyed to the developing section 6 which is the next process in a washed state. By introducing these processes, quality such as printing durability can be improved or the quality can be stabilized. In addition, although two processes of the said preheating part and a pre-water washing part may be put into both, depending on material prescription, either one may be introduce | transduced.

<Example>
Self-machine Haase (Germany) TOPLINE OE40,
Developer tank capacity 92 liters,
The capacity of the external tank in the present invention is 8 liters, a total of 100 liters,
The pump capacity for liquid circulation between the external tank and the main development tank is 200cc / min.
Developer: (A) Aqueous solution 1 was prepared. The unit is [g]. The pH of the aqueous solution 1 was 4.3.
8970 g of water
Anionic surfactant (the following chemical formula) 400 g

アラビアガム １５０ ｇ
酵素変性馬鈴薯澱粉 ４００ ｇ
ジオクチルスルホコハク酸エステルのナトリウム塩 ５０ ｇ
第一燐酸アンモニウム １０ ｇ
クエン酸 １０ ｇ
ＥＤＴＡ−４−ナトリウム塩 １０ ｇ
ｐＨ ４．３、

Gum arabic 150 g
Enzyme-modified potato starch 400 g
Dioctyl sulfosuccinate sodium salt 50 g
Primary ammonium phosphate 10 g
Citric acid 10 g
EDTA-4-sodium salt 10 g
pH 4.3,

Planographic printing plate precursor:
Preparation of support body To remove rolling oil on the surface of an aluminum plate (material 1050) having a thickness of 0.3 mm, after performing a degreasing treatment at 50 ° C. for 30 seconds using a 10 mass% sodium aluminate aqueous solution, the bristle diameter The aluminum surface was grained using ^three 0.3 mm bundle-planted nylon brushes and a pumice-water suspension (specific gravity 1.1 g / cm ³ ) having a median diameter of 25 μm and washed well with water. This plate was etched by being immersed in a 25 mass% sodium hydroxide aqueous solution at 45 ° C for 9 seconds, washed with water, further immersed in 20 mass% nitric acid at 60 ° C for 20 seconds, and washed with water. At this time, the etching amount of the grained surface was about 3 g / m ² .

Next, an electrochemical roughening treatment was performed continuously using an alternating voltage of 60 Hz.
The electrolytic solution at this time was a 1% by mass nitric acid aqueous solution (containing 0.5% by mass of aluminum ions) and a liquid temperature of 50 ° C. The AC power source waveform is electrochemical roughening treatment using a trapezoidal rectangular wave alternating current with a time ratio TP of 0.8 msec until the current value reaches a peak from zero, a duty ratio of 1: 1, and a trapezoidal rectangular wave alternating current. Went. Ferrite was used for the auxiliary anode.
The current density was 30 A / dm ² at the peak current value, and 5% of the current flowing from the power source was shunted to the auxiliary anode. The amount of electricity in nitric acid electrolysis was 175 C / dm ² when the aluminum plate was the anode.
Then, water washing by spraying was performed.

Next, a 0.5% by mass hydrochloric acid aqueous solution (containing 0.5% by mass of aluminum ions) and an electrolytic solution having a liquid temperature of 50 ° C. and nitric acid electrolysis under the condition of an electric quantity of 50 C / dm ² when the aluminum plate is an anode. In the same manner as above, an electrochemical surface roughening treatment was performed, followed by washing with water by spraying.
The plate was provided with a direct current anodized film of 2.5 g / m ² at a current density of 15 A / dm ² using 15% by mass sulfuric acid (containing 0.5% by mass of aluminum ions) as an electrolytic solution, then washed with water and dried.
The centerline average roughness (Ra) of this substrate was measured using a needle having a diameter of 2 μm and found to be 0.51 μm.

Next, the following undercoat liquid (1) was applied so that the dry coating amount was 10 mg / m ² to prepare a support used in the following experiments.

Undercoat liquid (1)
・ Undercoat compound (1) below 0.017g
・ Methanol 9.00 g
・ Water 1.00g

A photosensitive layer coating solution (1) having the following composition was bar-coated on the support provided with the above-mentioned undercoat layer, followed by oven drying at 70 ° C. for 60 seconds, and image recording with a dry coating amount of 1.1 g / m ² . A protective layer coating solution (1) having the following composition was applied thereon using a bar so that the dry coating amount would be 0.75 g / m ^2, and then at 125 ° C. for 70 seconds. The lithographic printing plate precursor was obtained by drying.

<Photosensitive layer coating solution (1)>
・ The following binder polymer (1) (weight average molecular weight 80,000) 0.54 g
・ Polymerizable compound 0.40g
Isocyanuric acid EO-modified triacrylate (manufactured by Toa Gosei Co., Ltd., Aronix M-315)
・ Polymerizable compound Ethoxylated trimethylolpropane triacrylate 0.08 g
(Nippon Kayaku Co., Ltd., SR9035, EO addition mole number 15, molecular weight 1000)
・ The following sensitizing dye (1) 0.06 g
・ The following polymerization initiator (2) 0.18 g
・ The following chain transfer agent (1) 0.07 g
・ 0.40 g of ε-phthalocyanine pigment dispersion
(Pigment: 15 parts by mass, dispersant Binder polymer (1): 10 parts by mass,
Solvent cyclohexanone / methoxypropyl acetate / 1-methoxy-2-propanol = 15 parts by mass / 20 parts by mass / 40 parts by mass)
・ Thermal polymerization inhibitor 0.01g
N-nitrosophenylhydroxylamine aluminum salt ・ The following water-soluble fluorosurfactant (1) 0.001 g
・ Polyoxyethylene-polyoxypropylene condensate 0.04g
(Asahi Denka Kogyo Co., Ltd., Pluronic L44)
・ Tetraethylamine hydrochloride 0.01g
・ 3.5 g of 1-methoxy-2-propanol
・ Methyl ethyl ketone 8.0g

Protective layer coating solution (1)
Polyvinyl alcohol (saponification degree 98 mol%, polymerization degree 500) 40 g
Polyvinylpyrrolidone (weight average molecular weight 50,000) 5g
Poly (vinyl pyrrolidone / vinyl acetate (1/1)) (weight average molecular weight 70,000) 0.5 g
Surfactant (Emalex 710, manufactured by Nippon Emulsion Co., Ltd.) 0.5g
950g of water
Development processing The total area of 2000 m ² was developed with the automatic development apparatus shown in FIG. No replenishment. The total amount of developer used was 100 liters.

<Comparative example>
TOPLINE OE40 manufactured by Haase (Germany) (automatic developing device shown in FIG. 4B)
Developer tank capacity 92 liters
Developer High alkaline developer pH 12
Prescription pure water 950.0
EDTA (Tetradiaminetetraacetate) 1.5
Potassium carbonate 2.2
KOH (48%) 1.5
Polyethylene naphthyl ether (C = 14) 46.0
Planographic printing plate precursor: Fujifilm CTP plate LP-NNV (photopolymerization type CTP lithographic printing plate)
Developed with OE40 the developing processing total area of 2000m ² over a period of about one month. In order to maintain the development performance, the developer was replenished. Total usage reached 258 liters.

<Non-alkaline aqueous solution>
The lithographic printing plate precursor in the present invention 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 having a pH of 2 to 10, thereby forming a protective layer and a non-exposed portion of the photosensitive layer. It can be 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 4 to 9.5. 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 the like, or an aqueous solution containing a water-soluble polymer compound is preferable. 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 5-9, and still more preferably 6-8.5.

  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 sulfate salts, alkyl sulfate ester salts, polyoxyethylene alkyl etherate ester salts, fatty acid monog Ceride sulfates, polyoxyethylene alkylphenyl ether sulfates, polyoxyethylene styryl phenyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkylphenyl ether phosphates, 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.

  In addition, 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 (Hydrophile-Lipophile Balance) value of 6 or more, and 8 or more. It is more preferable that Furthermore, the ratio of the nonionic surfactant contained in the aqueous solution is preferably 0.1 to 10% by weight, and more preferably 1 to 10% 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 an organic solvent. Examples of the organic solvent that can be contained include aliphatic hydrocarbons (hexane, heptane, “Isopar E, H, G” (manufactured by Esso Chemical Co., Ltd.) or gasoline, kerosene, etc.), and aromatic hydrocarbons (toluene). , Xylene, etc.), or halogenated hydrocarbons (methylene dichloride, ethylene dichloride, trichlene, monochlorobenzene, etc.), polar solvents such as alcohols and esters.
In addition, when the organic solvent is insoluble in water, it can be used after being solubilized in water using a surfactant or the like. When the organic solvent is contained in the aqueous solution, it is safe and flammable. From this viewpoint, the concentration of the solvent is preferably less than 20% by weight.

  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]
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 of the present invention, a water-insoluble polymer is preferably used. Furthermore, the hydrophobic binder polymer that can be used in the present invention preferably contains substantially no acid group such as a carboxyl group, a sulfone group, and a phosphoric acid group. The acid value of the binder polymer (the acid content per gram of polymer) Is expressed as a chemical equivalent number) is preferably 0.3 meq / g or less, and more preferably 0.1 meq / g or less.
That is, the hydrophobic binder polymer that can be used in the present invention is preferably insoluble in water and an aqueous solution of pH 10 or higher, and the solubility of the hydrophobic binder polymer in water and an aqueous solution of pH 10 or higher is 0.5% by mass or less. Preferably, it is 0.1% by mass or less. 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 of the present invention 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.

  Here, the crosslinkable group is a group that crosslinks the polymer binder in the process of radical polymerization reaction that occurs in the photosensitive layer when the lithographic printing plate precursor is exposed. Although it will not specifically limit if it is a group of such a function, For example, an ethylenically unsaturated bond group, an amino group, an epoxy group etc. are mentioned as a functional group which can be addition-polymerized. Moreover, the functional group which can become a radical by light irradiation may be sufficient, and as such a crosslinkable group, a thiol group, a halogen group, an onium salt structure etc. are mentioned, for example. Especially, an ethylenically unsaturated bond group is preferable and the functional group represented by the following general formula (1)-(3) is especially preferable.

  In the general formula (1), R1 to R3 each independently represents a monovalent organic group, and R1 is preferably a hydrogen atom or an alkyl group which may have a substituent. Of these, a hydrogen atom and a methyl group are preferable because of high radical reactivity. R2 and R3 each independently represent a hydrogen atom, a halogen atom, an amino group, a carboxyl group, an alkoxycarbonyl group, a sulfo group, a nitro group, a cyano group, an alkyl group which may have a substituent, or a substituent. An aryl group that may have, an alkoxy group that may have a substituent, an aryloxy group that may have a substituent, an alkylamino group that may have a substituent, and a substituent Examples include a good arylamino group, an alkylsulfonyl group that may have a substituent, and an arylsulfonyl group that may have a substituent. Among them, a hydrogen atom, a carboxyl group, an alkoxycarbonyl group, and a substituent are included. An alkyl group which may be substituted and an aryl group which may have a substituent are preferable because of high radical reactivity.

  X represents an oxygen atom, a sulfur atom, or N (R12)-, and R12 represents a hydrogen atom or a monovalent organic group. Examples of R12 include an alkyl group which may have a substituent, and among them, a hydrogen atom, a methyl group, an ethyl group, and an isopropyl group are preferable because of high radical reactivity.

  Here, examples of the substituent that can be introduced include an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an alkoxy group, an aryloxy group, a halogen atom, an amino group, an alkylamino group, an arylamino group, a carboxyl group, an alkoxycarbonyl group, A sulfo group, a nitro group, a cyano group, an amide group, an alkylsulfonyl group, an arylsulfonyl group and the like can be mentioned.

  In the general formula (2), R4 to R8 each independently represents a monovalent organic group, and R4 to R8 are preferably a hydrogen atom, a halogen atom, an amino group, a dialkylamino group, a carboxyl group, an alkoxy group. A carbonyl group, a sulfo group, a nitro group, a cyano group, an alkyl group which may have a substituent, an aryl group which may have a substituent, an alkoxy group which may have a substituent, and a substituent An aryloxy group which may have a substituent, an alkylamino group which may have a substituent, an arylamino group which may have a substituent, an alkylsulfonyl group which may have a substituent, and a substituent. Examples include a good arylsulfonyl group, and among them, a hydrogen atom, a carboxyl group, an alkoxycarbonyl group, an alkyl group which may have a substituent, and an aryl group which may have a substituent are preferable.

  Examples of the substituent that can be introduced are the same as those in the general formula (1). Y represents an oxygen atom, a sulfur atom, or N (R12)-. R12 has the same meaning as R12 in formula (1), and preferred examples thereof are also the same.

  In the general formula (3), R9 is preferably a hydrogen atom or an alkyl group which may have a substituent. Among them, a hydrogen atom or a methyl group is preferable because of high radical reactivity. . R10 and R11 are each independently a hydrogen atom, a halogen atom, an amino group, a dialkylamino group, a carboxyl group, an alkoxycarbonyl group, a sulfo group, a nitro group, a cyano group, an optionally substituted alkyl group, a substituted group An aryl group that may have a group, an alkoxy group that may have a substituent, an aryloxy group that may have a substituent, an alkylamino group that may have a substituent, and a substituent An arylamino group which may have a substituent, an alkylsulfonyl group which may have a substituent, an arylsulfonyl group which may have a substituent, and the like. Among them, a hydrogen atom, a carboxyl group, an alkoxycarbonyl group, a substituent An alkyl group which may have a substituent and an aryl group which may have a substituent are preferable because of high radical reactivity.

Here, examples of the substituent that can be introduced are the same as those in the general formula (1). Z represents an oxygen atom, a sulfur atom, -N (R13)-, or a phenylene group which may have a substituent. Examples of R13 include an alkyl group which may have a substituent. Among them, a methyl group, an ethyl group, and an isopropyl group are preferable because of high radical reactivity.
Among these, (meth) acrylic acid copolymers having a crosslinkable group in the side chain and polyurethane are more preferable.

  Hydrophobic binder polymers having crosslinkability include, for example, free radicals (polymerization initiation radicals or growth radicals in the polymerization process of a polymerizable compound) added to the crosslinkable functional group, and polymerization of polymerizable compounds directly between polymers. Addition polymerization through a chain forms a cross-link between polymer molecules and cures. Alternatively, atoms in the polymer (eg, hydrogen atoms on carbon atoms adjacent to the functional bridging group) are abstracted by free radicals to form polymer radicals that are bonded to each other so that crosslinking between the polymer molecules occurs. Forms and cures.

  The content of the crosslinkable group in the hydrophobic binder polymer (content of unsaturated double bond capable of radical polymerization by iodine titration) is preferably 0.1 to 10.0 mmol, more preferably 1 g per 1 g of the hydrophobic binder polymer. Is 1.0 to 7.0 mmol, most preferably 2.0 to 5.5 mmol.

  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, in the present invention, 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 used in the present invention is a compound that initiates and accelerates the polymerization of a compound having a polymerizable unsaturated group by generating radicals by light or thermal energy. 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, P. The compound as described in Hutt, "Journal of Heterocyclic Chemistry", 1 (No. 3) (1970) is mentioned. Of these, oxazole compounds and S-triazine compounds substituted with a trihalomethyl group are preferred.

Examples of the carbonyl compound include benzophenone, Michler ketone, 2-methylbenzophenone, 3-methylbenzophenone, 4-methylbenzophenone, 2-chlorobenzophenone, 4-bromobenzophenone, and the like.

  As the azo compound, for example, an azo compound described in JP-A-8-108621 can be used.

  Examples of the metallocene compound include JP-A-59-152396, JP-A-61-151197, JP-A-63-41484, JP-A-2-249, JP-A-2-4705, Examples include various titanocene compounds described in Kaihei 5-83588, and iron-arene complexes described in JP-A-1-152109.

  Examples of the hexaarylbiimidazole compound include the specification of JP-B-6-29285, U.S. Pat. Nos. 3,479,185, 4,311,783, and 4,622,286. And various compounds described in 1. above.

  Examples of the organic boron compound include organic borates described in JP-A No. 2002-116539 and Kunz, Martin “Rad Tech '98. Proceeding April 19-22, 1998, Chicago”, and the like. JP-A-6-157623, JP-A-6-175564, JP-A-6-175561, organoboron sulfonium complexes or organoboron oxosulfonium complexes, JP-A-6-175554, JP-A-6-175553 Organoboron iodonium complexes described in JP-A-9-188710, organoboron phosphonium complexes described in JP-A-9-188710, JP-A-6-34881, JP-A-7-128785, JP-A-7-140589, JP-A-7 -306527, JP, Organoboron transition metal coordination complexes of JP-like 7-292014 are exemplified.

  Examples of the disulfone compound include compounds described in JP-A Nos. 61-166544 and 2003-328465.

  Examples of the oxime ester compound include JCS Perkin II (1979) 1653-1660), JCSPerkin II (1979) 156-162, Journal of Photopolymer Science and Technology (1995) 202-232, and JP-A 2000-66385. And compounds described in JP 2000-80068 A.

  Examples of the onium salt compound include S.I. I. Schlesinger, Photogr. Sci. Eng. 18, 387 (1974), T .; S. Diazonium salts described in Bal et al, Polymer, 21, 423 (1980), ammonium salts described in US Pat. No. 4,069,055, JP-A-4-365049, etc., US Pat. No. 4,069 , 055, 4,069,056, phosphonium salts described in European Patent Nos. 104,143, US Pat. Nos. 339,049, 410,201, JP -150848, JP-A-2-296514, iodonium salts, European Patent Nos. 370,693, 390,214, 233,567, 297,443, and 297 442, U.S. Pat. Nos. 4,933,377, 161,811, 410,201, 339,049, 4,760,013 No. 4,734,444, No. 2,833,827, German Patent No. 2,904,626, No. 3,604,580, No. 3,604,581 Or a sulfonium salt described in J. V. Crivello et al, Macromolecules, 10 (6), 1307 (1977), J. MoI. V. Crivello et al, J.A. Polymer Sci. , Polymer Chem. Ed. , 17, 1047 (1979), a selenonium salt described in C.I. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988), and onium salts such as arsonium salts.

In the present invention, these onium salts function not as acid generators but as ionic radical polymerization initiators.
The onium salt suitably used in the present invention is an onium salt represented by the following general formulas (RI-I) to (RI-III).

  In the formula (RI-I), Ar 11 represents an aryl group having 20 or less carbon atoms which may have 1 to 6 substituents. From the viewpoint of stability, perchlorate ion, hexafluorophosphate ion, tetra Fluoroborate ions, sulfonate ions and sulfinate ions are preferred.

  In formula (RI-II), Ar 21 and Ar 22 each independently represent an aryl group having 20 or less carbon atoms which may have 1 to 6 substituents, and preferred substituents are those having 1 to 12 carbon atoms. An alkyl group, an alkenyl group having 1 to 12 carbon atoms, an alkynyl group having 1 to 12 carbon atoms, an aryl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryloxy group having 1 to 12 carbon atoms, a halogen atom An alkylamino group having 1 to 12 carbon atoms, a dialkylamino group having 1 to 12 carbon atoms, an alkylamide group or arylamide group having 1 to 12 carbon atoms, a carbonyl group, a carboxyl group, a cyano group, a sulfonyl group, and 1 carbon atom -12 thioalkyl group and C1-C12 thioaryl group are mentioned. Z21- represents a monovalent anion. Specifically, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, and carboxylate ion are preferable from the viewpoints of stability and reactivity.

  In formula (RI-III), R31, R32 and R33 each independently represents an aryl group, alkyl group, alkenyl group or alkynyl group having 20 or less carbon atoms, which may have 1 to 6 substituents. . Among them, an aryl group is preferable from the viewpoint of reactivity and stability. Z31- represents a monovalent anion. As specific examples, perchlorate ions, hexafluorophosphate ions, tetrafluoroborate ions, sulfonate ions, sulfinate ions, and carboxylate ions are preferable in terms of stability and reactivity. More preferred are the carboxylate ions described in JP-A No. 2001-343742, and particularly preferred are the carboxylate ions described in JP-A No. 2002-148790.

  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 used in the present invention 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.

  Particularly preferred among these dyes are cyanine dyes, squarylium dyes, pyrylium salts, nickel thiolate complexes, and indolenine cyanine dyes.

  Examples of the pigment used in the present invention include commercially available pigments and color index (CI) manual, “Latest Pigment Handbook” (edited by Japan Pigment Technology Association, published in 1977), “Latest Pigment Application Technology” (CMC Publishing, 1986), “Printing Ink Technology”, 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.

  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.

  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.

  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 for the photosensitive layer in the present invention is an addition polymerizable compound having at least one ethylenically unsaturated double bond, and is a compound having at least one terminal ethylenically unsaturated bond, preferably two or more. To be elected. Such a compound group is widely known in the industrial field, and can be used without any particular limitation in the present invention. 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.

(Microcapsule)
In the present invention, as a method for causing the photosensitive layer to contain the above-described photosensitive layer constituents and other constituents described later, for example, as described in JP-A Nos. 2001-277740 and 2001-277742, A part of the components 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.

  A preferable microcapsule wall used in the present invention has a three-dimensional cross-linking and has 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 present invention, it is preferable to use a surfactant in the photosensitive layer 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.

(Hydrophilic polymer)
In the present invention, a hydrophilic polymer can be contained in order to improve developability and dispersion stability of microcapsules.
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.

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)
In the present invention, 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 of the present invention, a compound that changes color by an acid or a radical can be added in order to form 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.

  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)
In order to prevent unnecessary thermal polymerization of the radical polymerizable compound during the production or storage of the photosensitive layer, it is preferable to add a small amount of a thermal polymerization inhibitor to the photosensitive layer of the present invention.
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 behenamide is added to the photosensitive layer of the present invention so that it is unevenly distributed on the surface of the photosensitive layer during the drying process after coating. May be. 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 of the present invention 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 of the present invention may contain inorganic fine particles in order to improve the cured film strength of the image area. As the inorganic fine particles, for example, silica, alumina, magnesium oxide, titanium oxide, magnesium carbonate, calcium alginate, or a mixture thereof is preferably exemplified. 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 of the present invention 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 of the present invention can contain, for example, a cosensitizer.

<Formation of photosensitive layer>
The photosensitive layer of the present invention 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.

Moreover, although the photosensitive layer coating amount (solid content) on the support obtained after coating and drying varies depending on the application, it is generally preferably 0.3 to 3.0 g / m ² . 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 according to the invention 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 used in the present invention preferably has an oxygen permeability A at 25 ° C. and 1 atm of 1.0 ≦ A ≦ 20 (mL / m ² · day). If the oxygen permeability A is less than 1.0 (mL / m ² · day) and extremely low, unnecessary polymerization reaction occurs during production and raw storage, and unnecessary fogging and image streaking occur during image exposure. The problem that fatness arises arises. On the contrary, 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.
Furthermore, the protective layer in the lithographic printing plate precursor according to the invention preferably contains an inorganic stratiform 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
[However, A is any one of K, Na, and Ca, B and C are any 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. Further, as the synthetic mica, non-swelling 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} /5 Li Examples thereof include swelling mica such as _1/8 (Si ₄ O ₁₀ ) F ₂ . Synthetic smectite is also useful.

  As for the particle diameter of the inorganic stratiform compound used in the present invention, 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.

  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, it is 0.1 to 0.5 g / m ^2. The range is more preferably m ² , and more preferably 0.5 to 5 g / m ² when no inorganic layered compound is contained.

<Support>
The support used in the lithographic printing plate precursor according to the invention 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 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.

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 / dm 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 1.0 to 5.0 g / m ² , and 1.5 to 4
. More preferably, it is 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 used in the present invention, the substrate having the above-mentioned surface treatment and having an anodized film may be used as it is, but for further improvement in adhesion to the upper layer, hydrophilicity, resistance to contamination, heat insulation and the like. If necessary, it contains a micropore enlargement treatment, a micropore sealing treatment, and a hydrophilic compound described in Japanese Patent Application Laid-Open Nos. 2001-253181 and 2001-322365. A surface hydrophilization treatment immersed in an aqueous solution can be selected as appropriate. Of course, these enlargement processing and sealing processing are not limited to those described above, and any conventionally known method can be performed.

  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.

<Undercoat layer>
In the lithographic printing plate precursor according to the invention, 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 to 100 mg / m ² , and more preferably from 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.

1 is a configuration diagram of an automatic developing device according to Embodiment 1 of the present invention. FIG. It is a block diagram of the modification of the automatic developing device of FIG. It is a block diagram of the automatic developing apparatus which concerns on Embodiment 2 of this invention. (A) is an automatic developing device according to Embodiment 2, and (b) is a configuration diagram of a conventional automatic developing device.

Explanation of symbols

2, 2 ', 2 "Automatic development apparatus 4 according to the present invention Photosensitive planographic printing plate (PS plate)
6 Developing unit 10 Drying unit 12 Side plate 14 Insertion port 16 Carry-in roller 18 Rubber blade 20 Developing tank 22 Transport roller 24 Brush roller (rubbing member)
26 squeezing roller 27 plate detection sensor 29 pressure roller 36 guide roller 38 skewer roller 40 outlet 46 passage 50 controller 51 control ROM and RAM
52 Time measuring section 55 Developer storage tank (external tank)
58 Developer 60 Shielding lid 62 Rubber blade 71 Developer circulation pump 73 Conductivity sensor 74 Developer supply pump 80 First circulation pipe 90 Second circulation pipe 98 Display device 99 Alarm device

Claims (4)

An lithographic printing plate automatic developing device for removing an unnecessary portion of the image recording layer by bringing the lithographic printing plate on which the image recording layer on the support is image-exposed into contact with a developer,
A rubbing member for rubbing the lithographic printing plate in contact with the developer;
A squeezing roller provided downstream of the rubbing member and squeezing the developer attached to the lithographic printing plate;
A pressure roller that is disposed between the rubbing member and the squeezing roller and presses the planographic printing plate;
An automatic developing device for a lithographic printing plate, comprising:   2. The lithographic printing plate automatic developing device according to claim 1, wherein the lithographic printing plate is pressed by the pressure roller while the lithographic printing plate is immersed in the developer.   The lithographic plate according to any one of claims 1 to 2, wherein the main component of the developer contains 0.1 to 15% by mass of a surfactant and has a pH of 4 to 9.5. Automatic developing device for printing plates.   The lithographic printing plate automatic developing device according to claim 3, wherein the developer component contains 1 to 10% by mass of a water-soluble resin.

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