JP2005189310A - Image forming method and image exposure apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming method by which an image can be formed without passing through a liquid development process after image exposure and by which a lithographic printing plate excellent in printing durability can be obtained, and to provide an image exposure apparatus suitable for the method. <P>SOLUTION: The image exposure apparatus 10 performs scanning exposure of a lithographic printing plate precursor 12 with an infrared laser on the basis of digital image information to form an image corresponding to the digital image information. An image recording layer of the lithographic printing plate precursor 12 contains microcapsules housing a cationic polymerizable compound, an acid generator and a photothermal conversion agent. In the image exposure apparatus 10, an exposure head 26 is disposed opposite to an outer drum 20 and the lithographic printing plate precursor 12 fixed on the outer drum 20 is subjected to scanning exposure with IR laser light L. The image exposure apparatus 10 is provided with a ultraviolet irradiator 38 in a feeding path and the whole surface of the lithographic printing plate precursor 12 conveyed to the outer drum 20 is nearly uniformly irradiated with UV by the ultraviolet irradiator 38. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming method and an image exposure apparatus. Specifically, the image forming method of a negative lithographic printing plate capable of making a plate without performing image exposure with infrared rays and special liquid development processing, and The present invention relates to an image exposure apparatus used therefor.

    The development of laser technology in recent years has been remarkable, and in particular, solid-state lasers and semiconductor lasers (hereinafter referred to as “infrared lasers” where appropriate) that emit infrared rays with a wavelength of 760 nm to 1200 nm can be easily obtained with high output and small size. Became. In particular, in the field of lithographic printing, these infrared lasers are very useful as a recording light source for a CTP (Computer to Plate) system that directly makes a printing plate from digital data such as a computer.

  Accordingly, many studies have been made on the lithographic printing plate for the CTP system. Among them, as an aim to further streamline the process and solve the waste liquid treatment problem, development-free lithographic printing plate precursors that can be printed on a printing press without being developed after exposure have been studied, and various methods have been studied. Has been proposed.

  One method of eliminating the development process is to mount the exposed lithographic printing plate precursor on the cylinder of the printing press, and supply dampening water and ink while rotating the cylinder, so that the non-image area of the lithographic printing plate precursor There is a method called on-press development that removes the toner. That is, the lithographic printing plate precursor is exposed and then mounted on a printing machine as it is, and the plate making process is completed in a normal printing process. This eliminates the need for a conventional liquid developing process using developing chemicals, thereby making it possible to rationalize the printing preparation process, eliminate the need for developing waste liquid processing, and the like.

  As such a lithographic printing plate precursor, there has been proposed a lithographic printing plate precursor containing a cross-linked hydrophilic layer on a substrate and containing a hot-melt material microencapsulated therein (see, for example, Patent Document 1). .) In this printing plate, the microcapsule is collapsed by the action of heat generated in the laser exposure area, the lipophilic substance in the capsule is dissolved, and the hydrophilic layer surface is hydrophobized.

  Other examples using microcapsules that also disintegrate by heat include microcapsules encapsulating a photopolymerizable monomer and a photosensitive resin, and lipophilic components that form an interaction with a three-dimensionally crosslinked hydrophilic layer. A lithographic printing plate precursor using a microcapsule enclosing a liquid crystal has also been proposed (see, for example, Patent Documents 2 and 3).

These lithographic printing plate precursors do not require development processing, but when a metal plate such as aluminum having a high thermal conductivity is used as a support, heat to be used for image formation diffuses into the support, and image recording is performed. There was a problem in that the curing of the layer in the vicinity of the contact interface with the support did not proceed sufficiently, and the strength of the image area was insufficient and the printing durability was poor.
International Publication No. 94/23954 Pamphlet Japanese Patent Laid-Open No. 62-250454 Japanese Patent No. 3206297

  An object of the present invention, which was made to solve the above-mentioned conventional problems, was that image formation was possible without passing through a special liquid development processing step after image exposure using infrared rays, and excellent printing durability. An object is to provide an image forming method capable of obtaining a lithographic printing plate and an image exposure apparatus suitable for the image forming method.

  As a result of intensive studies, the inventors of the present invention irradiate the image recording layer of the lithographic printing plate precursor with ultraviolet rays before performing image exposure on the lithographic printing plate precursor provided with a recording layer containing a specific microcapsule. The inventors have found that the above object can be achieved and have solved the present invention.

  That is, the image forming method of the present invention according to claim 1 includes an image recording layer containing a microcapsule enclosing a cationically polymerizable compound, an acid generator, and a photothermal conversion agent on a support. An image forming method for forming an image on a lithographic printing plate precursor, wherein the entire surface of the image recording layer of the lithographic printing plate precursor is irradiated with ultraviolet rays substantially uniformly, and an acid generator contained in the image recording layer An ultraviolet irradiation process for generating an acid from the image, and after completion of the activation process, an image exposure process for selectively exposing the lithographic printing plate precursor with infrared rays to form an image on the image recording layer of the lithographic printing plate precursor, It is characterized by including.

  The ultraviolet rays irradiated to the lithographic printing plate precursor are preferably those having a wavelength capable of effectively generating an acid from the acid generator in the system, and generally have a wavelength selected from a wavelength range of 200 nm to 400 nm. Ultraviolet light is preferred.

  The image exposure apparatus of the present invention according to claim 3 is an image exposure apparatus used in the image forming method, wherein a lithographic printing plate precursor can be mounted, and the mounted lithographic printing plate precursor is held. A holding member, ultraviolet irradiation means for irradiating the image recording layer of the lithographic printing plate precursor mounted on the holding member with ultraviolet rays, and selectively exposing the lithographic printing plate precursor held by the holding member with infrared rays, Exposure means for forming an image on the image recording layer of the lithographic printing plate precursor.

  The lithographic printing plate precursor according to the invention is characterized in that the recording layer contains a microcapsule encapsulating a cationically polymerizable compound, an acid generator, and a photothermal conversion agent. The image forming mechanism of such a lithographic printing plate precursor is as follows. The energy of infrared light in image exposure is converted into heat energy by the photothermal conversion agent, and the heat causes the microcapsule wall to collapse or become permeable, and the encapsulated cationically polymerizable compound is removed from the capsule. Released (exuded). Similarly, the acid generated from the acid generator by the energy of image exposure serves as a polymerization initiator for the cationic polymerizable compound released (exuded) out of the capsule, and initiates or advances the polymerization reaction, thereby causing surface hydrophobicity. This is a mechanism in which an image area, that is, an image portion is formed.

  However, with only the thermal energy used for image exposure, a sufficient amount (concentration) of acid is recorded to make the capsule wall permeable and further activate the acid generator to advance the curing reaction of the polymerizable compound. In the vicinity of the interface between the recording layer and the support, thermal diffusion (heat absorption) from the recording layer to the support occurs, and the polymerization reaction starts and progresses as described above. Since the necessary sufficient amount of acid was not sufficiently supplied, the recording layer was not sufficiently cured, and a strong and excellent printing durability could not be formed.

  Here, in the image forming method of the present invention, the entire surface of the image recording layer of the lithographic printing plate precursor is irradiated with ultraviolet rays substantially uniformly to generate an acid from the acid generator contained in the image recording layer. The lithographic printing plate precursor is selectively exposed with infrared rays to form an image on the image recording layer of the lithographic printing plate precursor. As a result, a sufficient amount of acid is generated in advance from the acid generator in the image recording layer, and then image exposure with infrared rays is performed before the acid generator is deactivated. That is, since a sufficient amount of acid is almost uniformly dispersed in the image recording layer at the start of exposure with infrared rays, the polymerizable compound released (exuded) from the capsules by simply breaking the capsules with energy by infrared rays A sufficient amount of acid initiates and proceeds the polymerization reaction. In addition, activation of the acid generator by irradiation with ultraviolet rays is performed uniformly up to the deep part of the image recording layer, unlike that by irradiation with infrared rays. Therefore, the polymerization reaction proceeds efficiently not only in the vicinity of the surface of the image recording layer but also in the vicinity of the interface between the image recording layer and the support due to the effect of heat absorption from the image recording layer to the support. An image having excellent properties can be formed.

  In the image exposure apparatus of the present invention, the ultraviolet ray irradiation means irradiates the image recording layer of the lithographic printing plate precursor mounted on the holding member with ultraviolet rays, and the exposure means holds the lithographic printing plate precursor held by the holding member with infrared rays. By selectively exposing, an image is formed on the image recording layer of the lithographic printing plate precursor. Thereby, after generating a sufficient amount of acid from the acid generator in the image recording layer, it is possible to perform image exposure with infrared rays, so that only the capsule wall material becomes permeable by infrared thermal energy, The polymerizable compound released (exuded) from the capsule can be polymerized with a sufficient amount of acid, and as a result, an image portion that is selectively strong and excellent in printing durability only at the exposed portion of the infrared beam. Can be formed.

  According to the present invention, after image exposure using infrared rays, an image can be formed without passing through a special liquid development processing step, and an image forming method capable of obtaining a lithographic printing plate excellent in printing durability. And this image forming method can be obtained.

[Configuration of image exposure apparatus]
First, an image exposure apparatus in which an image forming method according to the present invention is preferably implemented will be described with reference to the drawings.

(First embodiment)
1 to 3 show an image exposure apparatus according to a first embodiment of the present invention. The image exposure apparatus 10 scans and exposes a lithographic printing plate precursor 12 with an infrared laser (hereinafter referred to as “IR laser L”) modulated based on digital image information, and the lithographic printing plate precursor 12 has digital image information. An image (latent image) corresponding to is formed. Here, the lithographic printing plate precursor 12 is a so-called non-processed printing plate that does not require special development processing, and is formed on a support made of aluminum or an aluminum alloy and on this support. An image recording layer is provided, and this image recording layer (hereinafter simply referred to as “recording layer”) contains at least microcapsules enclosing a cationically polymerizable compound, an acid generator, and a photothermal conversion agent.

  The acid generator and the photothermal conversion agent may be added to at least one of the inside of the microcapsule and the outside of the microcapsule, that is, in the recording layer matrix. The generator is preferably added to the recording layer matrix. Moreover, it is preferable from a viewpoint of a sensitivity that a photothermal conversion agent is added in a microcapsule.

  As shown in FIG. 1, the image exposure apparatus 10 is provided with a casing 14 as an outer shell portion of the apparatus. The casing 14 has a side plate portion on one side along the width direction of the apparatus (direction of arrow W). A plate feeding table 16 for mounting a bundle of lithographic printing plate precursors 12 is attached to a platen, and a discharge tray 18 for discharging the exposed lithographic printing plate precursor 12 is attached to the upper side of the plate feeding table 16. It has been. In the casing 14, a cylindrical outer drum 20 on which a single lithographic printing plate precursor 12 can be attached and detached is rotatably arranged. On the outer peripheral side of the outer drum 20, a chuck mechanism 22 for chucking the front end portion and the rear end portion of the planographic printing plate precursor 12 on the outer drum 20 is provided, and the planographic printing plate precursor 12 is attached to the outer drum 20. A guide roller 24 for winding on the outer peripheral surface is installed.

  An exposure head 26 facing the outer drum 20 and a feed mechanism 28 that supports the exposure head 26 so as to be movable along the sub-scanning direction are disposed in the casing 14. The exposure head 26 and the feed mechanism 28 scan and expose the lithographic printing plate precursor 12 mounted on the outer drum 20 by the IR laser L modulated based on the digital image information, and convert the lithographic printing plate precursor 12 into digital image information. This is for forming a corresponding image. In the casing 14, a light source box 30 is disposed on the lower side of the outer drum 20, and an LD light source device 32 (see FIG. 2) for supplying the IR laser L to the exposure head 26 is disposed in the light source box 30. ) Is stored.

  As shown in FIG. 1, the image exposure apparatus 10 has a feeding for transporting a lithographic printing plate precursor 12 loaded on a plate feeding table 16 in a casing 14 to an outer drum 20 at a predetermined feeding speed. A mechanism 34 is provided. The feeding mechanism 34 includes a plurality of transport rollers 35 and a plate-shaped guide member 36 arranged along the feeding path of the planographic printing plate precursor 12 extending from the plate feeding table 16 to the upper end of the outer drum 20. ing. The feeding mechanism 34 is provided with an ultraviolet irradiation device 38 for irradiating the entire surface of the planographic printing plate precursor 12 with ultraviolet UV in the middle of the feeding path.

  As shown in FIG. 3, the ultraviolet irradiation device 38 includes a UV light source unit 40 that emits ultraviolet rays UV, and an integrator illumination optical system 42 that receives the ultraviolet rays UV from the UV light source unit 40. The UV light source unit 40 is provided with a long cylindrical UV lamp 44 as a light source of ultraviolet UV. The UV lamp 44 is supported so that its longitudinal direction is parallel to the plate width direction (the depth direction of the paper in FIG. 2) of the planographic printing plate precursor 12 conveyed by the feeding mechanism 34. In the UV light source unit 40, a reflector 46 having a parabolic reflecting surface 48 curved in a concave shape is disposed on the rear side of the UV lamp 44, and the UV lamp 44 is located near the focal point of the reflecting surface 48. ing. As a result, some of the ultraviolet rays UV emitted from the UV lamp 44 are directly incident on the integrator illumination optical system 42, and most of the remaining rays are reflected by the reflector 46 and incident on the integrator illumination optical system 42. To do.

  The integrator illumination optical system 42 includes a plurality (two in this embodiment) of fly array lenses 50 and 51. Each of these fly array lenses 50 and 51 is integrally formed with a plurality of lenses (lens groups) arranged in a lattice pattern along the plate width direction and the feeding direction (the direction of arrow F in FIG. 3). Yes. Here, the ultraviolet rays UV emitted from the UV light source unit 40 are incident on the lens group of the first fly array lens 50 to form a light source image on each lens group of the next fly array lens 51 (critical illumination). These light source images are light source images having different brightness along the feeding direction, but these light source images are centered on the optical axis along the feeding direction by the action of the lens group of the fly array lens 51. Since the same area is illuminated (Kohler illumination), the light quantity distribution of the ultraviolet UV along the feeding direction on the planographic printing plate precursor 12 is made substantially uniform.

The light quantity distribution along the plate width direction of the ultraviolet UV emitted from the UV lamp 44 is substantially uniform. Thereby, the ultraviolet irradiation device 38 is in the plate width direction of the planographic printing plate precursor 12 at a position where the optical axis of the integrator illumination optical system 42 intersects the feeding path (this is referred to as “irradiation position P _UV ”). Is irradiated with ultraviolet rays UV having a substantially uniform light quantity distribution per unit area (hereinafter referred to as “irradiation area A _UV ”). Here, the irradiation area A _UV has a width along the plate width direction wider than that of the planographic printing plate precursor 12.

In the image exposure apparatus 10, when conveyance of one lithographic printing plate precursor 12 supplied from the plate feeding table 16 is started by the feeding mechanism 34, at least when the lithographic printing plate precursor 12 is irradiated with ultraviolet UV, the supply is performed. The planographic printing plate precursor 12 is conveyed at a constant speed by the feeding mechanism 34. As a result, a certain amount of ultraviolet UV is irradiated on the entire surface of the image recording layer of the planographic printing plate precursor 12 that has passed the irradiation position P _UV .

  In the image exposure apparatus 10, when the planographic printing plate precursor 12 is conveyed to the vicinity of the upper end of the outer drum 20 by the feeding mechanism 34, the tip of the planographic printing plate precursor 12 is chucked on the outer drum 20 by the chuck mechanism 22. At the same time, the outer drum 20 starts to rotate in a predetermined forward rotation direction (the direction of arrow R1 in FIG. 1). As a result, the lithographic printing plate precursor 12 whose tip is restrained on the outer drum 20 by the tip clamp is wound while being pressed onto the outer peripheral surface of the outer drum 20 by the guide roller 24.

  In the image exposure apparatus 10, when the planographic printing plate precursor 12 is wound around the outer drum 20 to the rear end portion, the rear end portion of the planographic printing plate precursor 12 is chucked onto the outer drum 20 by the chuck mechanism 22. Thereby, the entire planographic printing plate precursor 12 is brought into close contact with the outer peripheral surface of the outer drum 20, and the mounting of the planographic printing plate precursor 12 to the outer drum 20 is completed. In the image exposure apparatus 10, the IR laser L emitted from the exposure head 26 while moving the exposure head 26 in the sub-scanning direction by the feed mechanism 28 with the lithographic printing plate precursor 12 mounted on the outer drum 20. Is irradiated onto the lithographic printing plate precursor 12 to perform sub-scanning exposure on the lithographic printing plate precursor 12. Further, the image exposure apparatus 10 can perform main scanning on the lithographic printing plate precursor 12 by rotating the outer drum 20 by a rotation amount corresponding to the main scanning pitch in the forward rotation direction in synchronization with the completion of one sub-scan. It has become.

  As shown in FIG. 2, the exposure head 26 includes a lens unit 58 that includes a plurality of lenses and forms an imaging optical system, a pair of support plates that sandwich the tips of a plurality of optical fibers 70, and light. A fiber holder 60 made of a transparent protective plate or the like for protecting the front end surface of the fiber 70 is mounted. Here, the IR lasers L respectively emitted from the plurality of optical fibers 70 are incident on the lens unit 58 and imaged on the planographic printing plate precursor 12 mounted on the outer drum 20 by the lens unit 58, and have a predetermined shape. A plurality of sets of beam spots are formed.

  Further, the feeding mechanism 28 includes a pair of guide rails 62 that support the exposure head 26 slidably along the sub-scanning direction (the direction of arrow S in FIG. 2) and a screw shaft 66 connected to the motor unit 64. . A block-shaped carrier 68 is fixed to the lower surface of the exposure head 26, and a screw shaft 66 is screwed into a female screw hole formed in the carrier 68. As a result, when the screw shaft 66 is rotated by the motor unit 64, the exposure head 26 adjusts the rotation amount of the screw shaft 66 in the direction corresponding to the rotation direction of the screw shaft 66 (forward direction or reverse direction) along the sub-scanning direction. Move the corresponding distance. In the image exposure apparatus 10 of the present embodiment, sub-scanning with respect to the planographic printing plate precursor 12 is performed only when the exposure head 26 moves forward, but sub-scanning (reciprocal scanning) is performed when the exposure head 26 moves forward and backward. Anyway.

  As shown in FIG. 2, the other ends of the plurality of optical fibers 70 are respectively connected to the plurality of semiconductor lasers 72 in the LD light source device 32. The semiconductor laser 72 in the LD light source device 32 is fixed on a heat sink 74 which is a plate-like heat radiator. A connector array 76 is provided in the middle of the optical fiber 70, and the optical fiber 70 can be brought into contact with and separated from the fiber holder 60 side and the semiconductor laser 72 side through the connector array 76. . Thereby, for example, when the semiconductor laser 72 fails, only the failed semiconductor laser 72 can be easily replaced without disassembling the fiber holder 60 or the like.

  In the feed mechanism 28, a tube-shaped cable bear 78 and a hook-shaped bear guide 80 are arranged below the guide rail 62 so as to extend in the sub-scanning direction. The cable bear 78 has a structure in which a large number of link pieces 82 divided in the longitudinal direction are linked in series, and is flexible in the vertical direction perpendicular to the sub-scanning direction. A portion (front end side) of the optical fiber 70 on the exposure head 26 side is inserted into the cable bear 78. Further, the bear guide 80 restricts the movement of the cable bear 78 in the front-rear direction while supporting the cable bear 78 from below. Thereby, when the exposure head 26 moves in the sub-scanning direction, the distal end side of the optical fiber 70 that moves together with the exposure head 26 is protected by the cable bear 78, and damage to the optical fiber 70 is prevented.

  As shown in FIG. 1, the image exposure apparatus 10 is provided with a carry-out mechanism 84 for carrying the lithographic printing plate precursor 12 detached from the outer drum 20 to the discharge tray 18 in the casing 14. The unloading mechanism 84 includes a plurality of conveying rollers 86 and a plate-shaped guide member 88 arranged along the unloading path of the planographic printing plate precursor 12.

  In the image exposure apparatus 10, after the exposure (image formation) to the lithographic printing plate precursor 12 mounted on the outer drum 20 is completed, the outer drum 20 is rotated in the reverse direction (in the direction of arrow R <b> 2 in FIG. 1) and the chuck mechanism 22. The rear end and the front end of the planographic printing plate precursor 12 are sequentially released from the outer drum 20. In conjunction with this, the carry-out mechanism 84 rotates the transport roller 86 to start transporting the planographic printing plate precursor 12 sent from the outer drum 20 to the entrance of the discharge path to the discharge tray 18. The printing plate precursor 12 is discharged onto the discharge tray 18.

(Second Embodiment)
FIG. 4 shows an image exposure apparatus according to a second embodiment of the present invention. In the image exposure apparatus 100 according to the second embodiment, the same reference numerals are given to the same parts as those of the image exposure apparatus 10 according to the first embodiment, and the description thereof is omitted.

  Similar to the image exposure apparatus 10 of the first embodiment, the image exposure apparatus 100 scans and exposes the lithographic printing plate precursor 12 with an IR laser L that is modulated based on digital image information. An image corresponding to digital image information is formed. As shown in FIG. 4, the image exposure apparatus 100 is different from the image exposure apparatus 10 in that the plate supply table 16 on which a bundle of planographic printing plate precursors 12 is loaded is omitted. Instead, the autoloader 102 is added as an optional unit, and the ultraviolet irradiation device 38 is moved from the casing 14 to the autoloader 102 side.

  The autoloader 102 is for supplying the lithographic printing plate precursor 12 to the feeding mechanism 34 in accordance with control from a control unit (not shown) of the image exposure apparatus 100 or a preset supply schedule. The autoloader 102 includes a loading unit 104 that can load a large number of lithographic printing plate precursors 12 and a separation unit that separates one lithographic printing plate precursor 12 from a bundle of lithographic printing plate precursors 12 loaded in the loading unit 104. A lithographic printing plate precursor 12 separated by a mechanism (not shown) and a separation mechanism is conveyed along a predetermined conveyance path, and is supplied to the feeding mechanism 34 on the image exposure apparatus 100 main body side of the image exposure apparatus 100. A transport mechanism 106 is provided.

  Here, the transport mechanism 106 includes a transport roller 108, a guide member 110, and the like arranged along the transport path. The planographic printing plate precursor 12 is input from the loading unit 104 to the feed path of the image exposure apparatus 100. It is transported to a part at a predetermined transport speed. Further, the autoloader 102 is provided with a casing 112 as an outer shell portion, and a bridge-shaped connecting portion 114 that connects the casing 112 to the casing 14 of the image exposure apparatus 100. In the autoloader 102, the planographic printing plate precursor 12 conveyed by the conveying mechanism 106 is conveyed into the casing 14 of the image exposure apparatus 100 through the connecting portion 114.

  The autoloader 102 is provided with an ultraviolet irradiation device 38 for irradiating the lithographic printing plate precursor 12 with ultraviolet UV in the connecting portion 114, and the ultraviolet irradiation device 38 is supplied to the feeding mechanism 34 by the transport mechanism 106. The entire surface of the image recording layer of the lithographic printing plate precursor 12 is irradiated with a predetermined amount of ultraviolet UV. The ultraviolet irradiation device 38 of the second embodiment basically has a common structure with that of the first embodiment. However, in the image exposure apparatus 100, since the distance from the ultraviolet irradiation device 38 to the outer drum 20 becomes longer and the conveyance time increases, the irradiation amount of the ultraviolet UV is set higher than the irradiation amount of the ultraviolet UV in the image exposure device 10. It may be necessary to do this. Therefore, the specifications of the output of the UV lamp 44 in the ultraviolet irradiation device 38 may be changed according to the setting value of the irradiation amount of the ultraviolet UV.

  In the image exposure apparatus 100 according to the second embodiment configured as described above, since the ultraviolet irradiation device 38 is disposed in the autoloader 102 as an optional unit, the structure of the main body of the image exposure apparatus 100 is as follows. This is the same as a conventional image exposure apparatus that does not include the ultraviolet irradiation device 38. Therefore, according to the image exposure apparatus 100, it is possible to irradiate the planographic printing plate precursor 12 with ultraviolet UV simply by adding the autoloader 102 as an optional unit to the main body of the conventional image exposure apparatus. The development cost and development time of an image exposure apparatus capable of irradiating with ultraviolet UV can be greatly reduced, and the image exposure apparatus already delivered to the user can be applied with UV UV only by adding the autoloader 102 and simple setting change. Can be modified to one that can be irradiated.

(Modified example of ultraviolet irradiation device)
Next, a case where an ultraviolet irradiation device using a GaN-based semiconductor laser as a light source instead of the ultraviolet irradiation device 38 using a UV lamp 44 as a light source is applied to the above-described image exposure apparatuses 10 and 100 will be described.

  FIG. 5 shows an ultraviolet irradiation apparatus using a GaN semiconductor laser as a light source. The ultraviolet irradiation device 120 can be applied to the image exposure apparatuses 10 and 100 in place of the ultraviolet irradiation device 38, and each includes a plurality of GaN-based semiconductor lasers (hereinafter simply referred to as “semiconductor lasers”) formed in a chip shape. 122) as a light source for ultraviolet rays UV. The semiconductor laser 122 in the ultraviolet irradiation device 120 is fixed on a heat sink 124 that is a heat radiating body, and an optical fiber 126 is connected to each of the semiconductor lasers 122.

The tip portions of the plurality of optical fibers 126 connected to the semiconductor laser 122 are a pair of support plates that sandwich the tip portions of the plurality of optical fibers 126, and a transparent protective plate for protecting the tip surface of the optical fiber 70. Etc. are held by a fiber holder 128 made of the like. Here, the fiber holder 128 is supported so as to be opposed to the lithographic printing plate precursor 12 which passes through the irradiation position P _UV. A connector array 130 is provided in the middle of the optical fiber 126, and the optical fiber 126 can be connected to and separated from the fiber holder 128 side portion and the semiconductor laser 122 side portion via the connector array 130. . Thereby, for example, when the semiconductor laser 122 fails, the failed semiconductor laser 72 can be easily replaced without disassembling the fiber holder 60 or the like.

  In the ultraviolet irradiation apparatus 120 shown in FIG. 5, one optical fiber 126 is connected to one semiconductor laser 122, but a plurality of semiconductor lasers 122 are provided for one optical fiber 126. At the same time, a multiplexing optical system including a collimator lens and a condenser lens is installed between the semiconductor laser 122 and the incident end face of the optical fiber 126, and the ultraviolet laser emitted from each semiconductor laser 122 is multiplexed. By making the light incident on one optical fiber 126, the output of the ultraviolet laser emitted from one optical fiber 126 may be increased.

In the ultraviolet irradiation device 120, an illumination optical system 132 is provided between the fiber holder 128 and the planographic printing plate precursor 12. The illumination optical system 132 is, for example, a combination of an enlargement optical system having a lens power in the plate width direction (arrow B direction in FIG. 5), an integrator illumination optical system, and the like, and is emitted from the fiber holder 128. A plurality of ultraviolet lasers are irradiated to the linear irradiation area A _UV along the plate width direction in the lithographic printing plate precursor 12 as ultraviolet light UV having a substantially uniform light quantity distribution per unit area.

When the ultraviolet irradiation device 120 shown in FIG. 5 is applied, in the image exposure devices 10 and 100, one lithographic printing plate precursor 12 supplied from the plate supply table 16 is started to be conveyed by the feeding mechanism 34. If, to emit a semiconductor laser 122 at a timing immediately before the tip of the planographic printing plate precursor 12 reaches the irradiation position P _UV, the semiconductor laser 122 immediately after the trailing end of the lithographic printing plate precursor 12 has passed the irradiated position P _UV extinction To do. In the image exposure apparatuses 10 and 100, at least when the lithographic printing plate precursor 12 is irradiated with ultraviolet UV, the lithographic printing plate precursor 12 is conveyed at a constant speed by the feeding mechanism 34. As a result, a certain amount of ultraviolet UV is irradiated on the entire surface of the image recording layer of the planographic printing plate precursor 12 that has passed the irradiation position P _UV .

  According to the ultraviolet irradiation device 120 described above, the output of the ultraviolet UV irradiated to the planographic printing plate precursor 12 can be easily adjusted by increasing or decreasing the number of semiconductor lasers 122 installed. Compared to 38, it is possible to irradiate the lithographic printing plate precursor 12 with higher-power ultraviolet UV. Therefore, when the ultraviolet irradiation device 120 is applied to the image exposure apparatuses 10 and 100, the feeding speed of the planographic printing plate precursor 12 by the feeding mechanism 34 is improved in order to improve the exposure processing capability of the image exposure apparatuses 10 and 100. Even when the feed rate is significantly increased, the output of ultraviolet rays UV can be easily increased in accordance with the increase in the feeding speed, and the lithographic printing plate precursor 12 can be reliably irradiated with the required amount of ultraviolet rays UV. .

  As described above, the lithographic printing plate precursor that has been subjected to image exposure by the image exposure apparatuses 10 and 100 and discharged onto the discharge tray 18 is then mounted on a printing press without being subjected to a special liquid developer. The ink can be printed by a normal procedure using ink and fountain solution. That is, the unexposed portion of the lithographic printing plate precursor after exposure is easily removed by an aqueous component contained in the fountain solution or an oily component such as ink at the initial stage of the printing process. Is exposed, and dampening water adheres to it to form a non-image area, and the hydrophobic area cured by exposure forms an ink-receptive image area.

  These lithographic printing plate precursors can also be used for printing after being subjected to a development treatment using water or an appropriate aqueous solution as a developer.

The lithographic printing plate precursor imaged by the method of the present invention is a so-called on-press development type because the image area is sufficiently cured by supplying sufficient starting seeds in the ultraviolet irradiation process and the image area is excellent in strength. The high printing durability, which has been a problem in lithographic printing plates, has been realized, and it has become possible to obtain a large number of good printed matter.
(Configuration of lithographic printing plate precursor)
Next, the configuration of a lithographic printing plate precursor that can be suitably applied to the method of the present invention and that can form an image without requiring a liquid development processing step will be described in detail.

The lithographic printing plate precursor according to the present invention comprises an image recording layer containing a microcapsule encapsulating a cationically polymerizable compound, an acid generator, and a photothermal conversion agent on a support.
(Image recording layer)
(Microcapsules encapsulating cationically polymerizable compounds)
The cationically polymerizable compound used in the present invention is not particularly limited as long as it is a compound having a cationically polymerizable group in the molecule. Among them, a compound having a vinyloxy group or an epoxy group is preferably used.

  Examples of the cationically polymerizable compound having a vinyloxy group suitable for the present invention include compounds described in JP-A-2002-29162.

  Specifically, tetramethylene glycol divinyl ether, trimethylolpropane trivinyl ether, tetraethylene glycol divinyl ether, pentaerythritol divinyl ether, pentaerythritol trivinyl ether, pentaerythritol tetravinyl ether, 1,4-bis {2- (vinyloxy) ethyloxy } Benzene, 1,2-bis {2- (vinyloxy) ethyloxy} benzene, 1,3-bis {2- (vinyloxy) ethyloxy} benzene, 1,3,5-tris {2- (vinyloxy) ethyloxy} benzene, 4,4′-bis {2- (vinyloxy) ethyloxy} biphenyl, 4,4′-bis {2- (vinyloxy) ethyloxy} diphenyl ether, 4,4′-bis {2- (vinyloxy) ester Ruoxy} diphenylmethane, 1,4-bis {2- (vinyloxy) ethyloxy} naphthalene, 2,5-bis {2- (vinyloxy) ethyloxy} furan, 2,5-bis {2- (vinyloxy) ethyloxy} thiophene, , 5-bis {2- (vinyloxy) ethyloxy} imidazole, 2,2-bis [4- {2- (vinyloxy) ethyloxy} phenyl] propane {bis (vinyloxyethyl) ether of bisphenol A}, 2,2- Bis {4- (vinyloxymethyloxy) phenyl} propane, 2,2-bis {4- (vinyloxy) phenyl} propane, and the like, among others, 2,2-bis [4- [2- (vinyloxy) ethyloxy] ] Phenyl] propane, bis (vinyloxyethyl) ether of bisphenol A, 2,2 Bis [4- (vinyloxymethyl) phenyl] propane, 2,2-bis [4- (vinyloxy) phenyl] propane is particularly preferred. The present invention is not limited to these.

  As the cationically polymerizable compound having an epoxy group suitable for the present invention, a compound having two or more epoxy groups is preferable, and a glycidyl ether compound obtained by a reaction of a polyhydric alcohol or a polyhydric phenol with epichlorohydrin or the like. Examples thereof include a prepolymer, and a polymer or copolymer of glycidyl acrylate or glycidyl methacrylate.

  Specifically, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, trimethylolpropane triglycidyl ether, diglycidyl ether of hydrogenated bisphenol A, hydroquinone diglycidyl Ether, resorcinol diglycidyl ether, diglycidyl ether or epichlorohydrin polyadduct of bisphenol A, diglycidyl ether or epichlorohydrin polyadduct of bisphenol F, diglycidyl ether or epichlorohydride of halogenated bisphenol A Phosphorus polyadduct, diglycidyl ether of biphenyl type bisphenol or epichlorohydrin polyadduct, novolac resin Examples include lysidyl etherified compounds, methyl methacrylate / glycidyl methacrylate copolymer, ethyl methacrylate / glycidyl methacrylate methacrylate, and the like. Among them, diglycidyl ether or epichlorohydrin polyadduct of bisphenol A Particularly preferred are diglycidyl ethers of biphenyl type bisphenols or epichlorohydrin heavy compounds. The present invention is not limited to these.

  Commercially available products of the above compounds include, for example, Epicoat 1001 (molecular weight: about 900, epoxy equivalent: 450 to 500), Epicoat 1002 (molecular weight: about 1600, epoxy equivalent: 600 to 700), Epicoat 1004 (about) manufactured by Japan Epoxy Resin Co., Ltd. 1060, epoxy equivalent 875-975), Epicoat 1007 (molecular weight about 2900, epoxy equivalent 2000), Epicoat 1009 (molecular weight about 3750, epoxy equivalent 3000), Epicoat 1010 (molecular weight about 5500, epoxy equivalent 4000), Epicoat 1100L (epoxy equivalent) 4000), Epikote YX31575 (epoxy equivalent 1200), Sumitomo Chemical Co., Ltd. Sumiepoxy ESCN-195XHN, ESCN-195XL, ESCN-195XF, and the like.

  Furthermore, the inclusion of the microcapsule according to the present invention may contain a thermopolymerizable compound having the following heat-reactive group in addition to the cationic polymerizable compound.

Examples of the thermally polymerizable group include an isocyanate group that undergoes an addition reaction, a block thereof, and a functional group having an active hydrogen atom that is a reaction partner with a cationically polymerizable group such as the epoxy group or vinyloxy group (for example, Amino group, hydroxy group, carboxy group, etc.),
A carboxy group that performs a condensation reaction, and a hydroxy group and an amino group that are reaction partners thereof,
Examples thereof include an acid anhydride that undergoes a ring-opening addition reaction, and an amino group and a hydroxy group that are reaction partners thereof.

  Suitable compounds having an isocyanate group for the present invention include tolylene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, xylylene diisocyanate, naphthalene diisocyanate, cyclohexanephenylene diisocyanate, isophorone diester. Examples thereof include isocyanate, hexamethylene diisocyanate, cyclohexyl diisocyanate, and compounds obtained by blocking these with alcohol or amine.

  Examples of the compound having an amino group suitable for the present invention include ethylenediamine, diethylenetriamine, triethylenetetramine, hexamethylenediamine, propylenediamine, and polyethyleneimine.

  Examples of the compound having a hydroxy group suitable for the present invention include compounds having a terminal methylol group, polyhydric alcohols such as pentaerythritol, and bisphenol / polyphenols.

  Examples of the compound having a carboxy group suitable for the present invention include aromatic polyvalent carboxylic acids such as pyromellitic acid, trimellitic acid, and phthalic acid, and aliphatic polyvalent carboxylic acids such as adipic acid.

  Suitable acid anhydrides for the present invention include pyromellitic acid anhydride and benzophenone tetracarboxylic acid anhydride.

  In the image recording layer according to the present invention, it is necessary to add a photothermal conversion agent and an acid generator to at least one of the microcapsule and the recording layer matrix. These components are added to the microcapsule. At this time, the resultant is dissolved or dispersed in the same solvent as that of the inclusion, and is included. Further, usable photothermal conversion agents and acid generators will be described later.

  As a method for microencapsulating each of the above components, known methods can be applied. For example, as a method for producing microcapsules, a method using coacervation as shown in U.S. Pat. Nos. 2,800,547 and 2,800,498, British Patent No. 990443, U.S. Pat. No. 3,287,154, Japanese Patent Publication No. 38-19574, No. 42-446. No. 42-711, interfacial polymerization method, US Pat. No. 3,418,250, US Pat. No. 3,660,304, method of polymer precipitation, US Pat. No. 3,796,669, method using isocyanate polyol wall material, US Pat. US Pat. No. 3,914,511 shows a method using an isocyanate wall material, US Pat. Nos. 4001140, 4087376, and 4089802 use a urea-formaldehyde-based or urea-formaldehyde-resorcinol-based wall forming material, A method using a wall material such as melamine-formaldehyde resin and hydroxycellulose, as shown in U.S. Pat. No. 4,025,445, an in situ method by monomer polymerization as shown in JP-B Nos. 36-9163 and 51-9079, British Patent No. 930422, US Pat. No. 3,111,407 And the like, but are not limited thereto, such as the spray drying method found in British Patent Nos. 952807 and 967074.

  A preferable microcapsule wall material used in the present invention has properties that it can swell in a coating solvent and can form a three-dimensional crosslink. 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. Further, a compound having a thermally reactive group may be introduced into the microcapsule wall.

  The average particle diameter of the obtained microcapsules is preferably 0.01 to 3.0 μm, more preferably 0.05 to 2.0 μm, and particularly preferably 0.10 to 1.0 μm. Within this range, good resolution and stability over time can be obtained.

  In addition, such microcapsules may be combined with each other by heat, or may not be combined. In short, the microcapsule inclusions ooze out from the capsule surface or outside the microcapsule by image exposure and cause a chemical reaction with the acid generated from the acid generator described later, or the acid penetrates into the microcapsule wall. It only has to cause a chemical reaction. Furthermore, you may react with the below-mentioned hydrophilic resin or low molecular compound added to a recording layer as an arbitrary component. In addition, the microcapsules may be reacted with each other by providing the microcapsules with different functional groups that are thermally reacted with each other. Therefore, it is preferable for image formation that the microcapsules are melted and united by heat, but it is not essential.

  The amount of such microcapsules added to the recording layer is preferably 50% by mass or more, and more preferably 70 to 98% by mass in terms of solid content in terms of solid content. Within this range, a good image can be formed and good printing durability can be obtained.

  In the recording layer containing microcapsules, a solvent capable of dissolving the inclusions of the microcapsules and swelling the wall material can be added to the microcapsule dispersion medium. By adding such a solvent, the diffusion of the microcapsule inclusions outside the capsule is promoted during image exposure.

  Such a solvent depends on the microcapsule dispersion medium, the material of the microcapsule wall, the wall thickness, and the inclusion, but can be easily selected from many commercially available solvents. For example, in the case of a water-dispersible microcapsule comprising a crosslinked polyurea or polyurethane wall, alcohols, ethers, acetals, esters, ketones, polyhydric alcohols, amides, amines, fatty acids and the like are preferable.

  Specific compounds include methanol, ethanol, tertiary butanol, n-propanol, tetrahydrofuran, methyl lactate, ethyl lactate, methyl ethyl ketone, propylene glycol monomethyl ether, ethylene glycol diethyl ether, ethylene glycol monomethyl ether, γ-butyl lactone, N, Examples include N-dimethylformamide and N, N-dimethylacetamide, but the present invention is not limited thereto. Two or more of these solvents may be used in combination. A solvent that does not dissolve alone in the microcapsule dispersion medium but dissolves by mixing the above-mentioned solvents can also be used.

The amount of such a solvent added depends on the combination of materials, but usually 5 to 95% by mass of the recording layer coating solution is effective, and a preferable range is 10 to 90% by mass, and a more preferable range is 15 It is -85 mass%.
(Photothermal conversion agent)
In the recording layer according to the present invention, it is necessary to add a photothermal conversion agent having a function of absorbing light energy and converting it into heat. In this case, a photothermal conversion agent may be added to at least one of the inside of the microcapsule and the recording layer matrix. In the present invention, from the viewpoint that infrared energy can efficiently contribute to image formability, It is preferable to add.

  The photothermal conversion agent may be any substance that absorbs infrared rays, particularly near infrared rays (wavelength 700 to 1200 nm), and various known pigments, dyes or pigments, and metal fine particles can be used.

  For example, the pigments, dyes or dyes described in JP 2001-301350 A, JP 2002-137562 A, Journal of the Japan Printing Society, Vol. 38, pages 35 to 40 (2001) “New imaging materials, 2. Near-infrared absorbing dyes”, etc. Dyes and fine metal particles are preferably used. As these pigments and metal fine particles, those subjected to a known surface treatment can be used as necessary.

  More specifically, as dyes or pigments, U.S. Pat. Nos. 4,756,993 and 4,973,572, JP-A-10-268512, JP-A-11-235883, JP-B-5-13514, JP-A-5-19702, and JP-A-2001-2001. Examples thereof include cyanine dyes, polymethine dyes, azomethine dyes, squarylium dyes, pyrylium and thiopyrylium salt dyes, dithiol metal complexes, and phthalocyanine dyes described in No. 347765. Particularly preferred are cyanine dyes, squarylium dyes, pyrylium salts, and phthalocyanine dyes.

  Examples of the pigment include 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, Kinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black, and the like can be used. Of these, carbon black is preferred.

  As the metal fine particles, fine particles of Ag, Au, Cu, Sb, Ge and Pb are preferable, and fine particles of Ag, Au and Cu are more preferable.

  Specific examples of particularly suitable photothermal conversion agents are shown below, but the present invention is not limited thereto. Note that (IR-1) to (IR-11) are hydrophilic photothermal conversion agents suitable for addition to the image recording layer matrix, and (IR-21) to (IR-29) are A lipophilic photothermal conversion agent suitable for inclusion in capsules.

光熱変換剤の添加量は、マイクロカプセル中に添加する場合には、全マイクロカプセル内包物の１〜５０質量％が好ましく、３〜２５質量％がより好ましい。一方、光熱変換剤を画像記録層マトリックス中に添加する場合には、記録層固形分の１〜５０質量％が好ましく、３〜２５質量％がより好ましい。この範囲において、記録層の膜強度を損なうことなく、良好な感度が得られる。
（酸発生剤）
本発明に係る記録層には、画像記録層マトリックス中に、光及び／又は熱により酸を発生し、前記カチオン重合性基の反応を開始、促進する酸発生剤を添加すことを要する。この場合、酸発生剤を前記マイクロカプセル内および画像記録層マトリックス中の少なくとも一方に添加すればよいが、安定性の観点から、カチオン重合性化合物とマイクロカプセル壁を隔てて存在するよう、記録層マトリックス中に添加することが好ましい。

When added to the microcapsule, the addition amount of the photothermal conversion agent is preferably 1 to 50% by mass, more preferably 3 to 25% by mass based on the total content of the microcapsules. On the other hand, when the photothermal conversion agent is added to the image recording layer matrix, 1 to 50% by mass of the solid content of the recording layer is preferable, and 3 to 25% by mass is more preferable. In this range, good sensitivity can be obtained without impairing the film strength of the recording layer.
(Acid generator)
In the recording layer according to the present invention, it is necessary to add an acid generator which generates an acid by light and / or heat and initiates and accelerates the reaction of the cationic polymerizable group in the image recording layer matrix. In this case, an acid generator may be added to at least one of the inside of the microcapsule and the image recording layer matrix, but from the viewpoint of stability, the recording layer should be separated from the cationically polymerizable compound and the microcapsule wall. It is preferable to add it to the matrix.

  The acid generator can also form a print-out system in combination with a dye that changes color due to the generated acid.

  As such an acid generator, a known acid precursor or a compound called an acid generator is preferably used. For example, an acid generator used for an acid generator for print-out image formation, a microresist or the like. Etc.

  More specifically, organic halogen compounds typified by trihalomethyl-substituted heterocyclic compounds described in JP-A-2002-29162, JP-A-2002-46361, JP-A-2002-137562, etc., iminosulfonates, etc. And compounds capable of generating a sulfonic acid by photolysis represented by (2), disulfone compounds, onium salts (for example, iodonium salts, diazonium salts, sulfonium salts, etc.). Moreover, the compound which introduce | transduced the group or compound which generate | occur | produces these acids into the principal chain or side chain of a polymer can also be used.

  Hereinafter, although a specific example is given, this invention is not limited to these.

本発明においては、紫外線照射による酸発生剤の活性化が画像記録層の硬化反応の効率化に寄与するため、２００〜４００ｎｍの波長の紫外線により高感度で分解、活性化する化合物を選択することが好ましい。

In the present invention, since activation of the acid generator by ultraviolet irradiation contributes to the efficiency of the curing reaction of the image recording layer, a compound that is decomposed and activated with high sensitivity by ultraviolet rays having a wavelength of 200 to 400 nm is selected. Is preferred.

  Two or more of the above acid generators can be used in combination.

  When added to the image recording layer matrix, the acid generator is preferably added in an amount of 0.01 to 20% by mass, more preferably 0.1 to 10% by mass, based on the total solids of the recording layer. Within this range, good reaction initiation or acceleration effect can be obtained without impairing on-press developability.

  Further, the recording layer according to the present invention can be added with a compound that is discolored by an acid in order to generate a printout image. As such a compound, various dyes such as diphenylmethane, triphenylmethane, thiazine, oxazine, xanthene, anthraquinone, iminoquinone, azo, and azomethine are effectively used.

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

  In addition to the above, a leuco dye known as a material for thermal paper or pressure-sensitive paper is also suitable. Specific examples include crystal violet lactone, malachite green lactone, benzoylleucomethylene blue, 2- (N-phenyl-N-methylamino) -6- (Np-tolyl-N-ethyl) amino-fluorane, 2-anilino. -3-methyl-6- (N-ethyl-p-toluidino) fluorane, 3,6-dimethoxyfluorane, 3- (N, N-diethylamino) -5-methyl-7- (N, N-dibenzylamino) ) -Fluorane, 3- (N-cyclohexyl-N-methylamino) -6-methyl-7-anilinofluorane, 3- (N, N-diethylamino) -6-methyl-7-anilinofluorane, 3 -(N, N-diethylamino) -6-methyl-7-xylidinofluorane, 3- (N, N-diethylamino) -6-methyl-7-chloro Fluorane, 3- (N, N-diethylamino) -6-methoxy-7-aminofluorane, 3- (N, N-diethylamino) -7- (4-chloroanilino) fluorane, 3- (N, N-diethylamino) -7-chlorofluorane, 3- (N, N-diethylamino) -7-benzylaminofluorane, 3- (N, N-diethylamino) -7,8-benzofluorane, 3- (N, N-dibutyl) Amino) -6-methyl-7-anilinofluorane, 3- (N, N-dibutylamino) -6-methyl-7-xylidinofluorane, 3-piperidino-6-methyl-7-anilinofluorane 3-pyrrolidino-6-methyl-7-anilinofluorane, 3,3-bis (1-ethyl-2-methylindol-3-yl) phthalide, 3,3-bis (1-n-butyl- -Methylindol-3-yl) phthalide, 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3- (4-diethylamino-2-ethoxyphenyl) -3- (1-ethyl- 2-methylindol-3-yl) -4-zaphthalide, 3- (4-diethylaminophenyl) -3- (1-ethyl-2-methylindol-3-yl) phthalide, and the like.

A suitable addition amount of the dye that changes color by the acid is 0.01 to 10% by mass with respect to the solid content of the recording layer.
(Hydrophilic resin)
The recording layer matrix according to the present invention may contain a hydrophilic resin in order to improve the on-press developability and the film strength of the recording layer itself.

  As hydrophilic resin, what has hydrophilic groups, such as a hydroxyl group, an amino group, a carboxy group, a phosphoric acid group, a sulfonic acid group, an amide group, is preferable, for example. In addition, the hydrophilic resin increases the image strength by reacting with the cationic polymerizable group possessed by the cationic polymerizable compound encapsulated in the microcapsule or the thermally reactive group possessed by the thermally polymerizable compound, thereby increasing the image resistance. Since it is printed, it is preferable to have a group that reacts with these functional groups. For example, when the cationically polymerizable compound has a vinyloxy group or an epoxy group, the hydrophilic resin preferably has a hydroxy group, a carboxy group, a phosphoric acid group, a sulfonic acid group, or the like. Among these, a hydrophilic resin having a hydroxy group or a carboxy group is preferable.

  Specific examples of hydrophilic resins include gum arabic, casein, gelatin, starch derivatives, soya gum, hydroxypropylcellulose, methylcellulose, carboxymethylcellulose and its sodium salt, cellulose acetate, sodium alginate, vinyl acetate-maleic acid copolymers, styrene-malein Acid copolymers, polyacrylic acids and their salts, polymethacrylic acids and their salts, homopolymers and copolymers of hydroxyethyl methacrylate, homopolymers and copolymers of hydroxyethyl acrylate, homopolymers and copolymers of hydroxypropyl methacrylate, hydroxypropyl acrylate Homopolymers and copolymers, hydroxybutyl methacrylate homopolymers and copolymers, Homopolymers and copolymers of butyl acrylate, polyethylene glycols, hydroxypropylene polymers, polyvinyl alcohols, hydrolyzed polyvinyl acetate having a degree of hydrolysis of at least 60% by weight, preferably at least 80% by weight, polyvinyl formal, polyvinyl pyrrolidone, acrylamide Homopolymers and copolymers, methacrylamide homopolymers and copolymers, N-methylolacrylamide homopolymers and copolymers, 2-acrylamido-2-methyl-1-propanesulfonic acid homopolymers and copolymers, 2-methacryloyloxyethylphosphonic acid And homopolymers and copolymers thereof.

  The amount of the hydrophilic resin added is preferably 20% by mass or less, more preferably 10% by mass or less, based on the total solid content of the recording layer.

Further, the hydrophilic resin may be used after being cross-linked to such an extent that an unexposed portion can be developed on-press on a printing press. Examples of crosslinking agents used to crosslink hydrophilic resins include glyoxal, melamine formaldehyde resins, aldehydes such as urea formaldehyde resins, N-methylol urea, N-methylol melamine, methylol compounds such as methylolated polyamide resins, and divinyl. Active vinyl compounds such as sulfone and bis (β-hydroxyethylsulfonic acid), epoxy compounds such as epichlorohydrin, polyethylene glycol diglycidyl ether, polyamide, polyamine, epichlorohydrin adduct, polyamide epichlorohydrin resin, monochloroacetic acid Ester compounds such as esters and thioglycolic acid esters, polycarboxylic acids such as polyacrylic acid and methyl vinyl ether / maleic acid copolymer, boric acid, titanyl sulfate, C , Al, Sn, V, inorganic crosslinking agents such as Cr salts, and modified polyamide polyimide resin. In addition, a crosslinking catalyst such as ammonium chloride, a silane coupling agent, a titanate coupling agent can be used in combination.
(Other additives)
In addition to the above, various compounds may be added to the recording layer matrix according to the present invention as necessary.
<Multifunctional monomer>
In order to further improve the printing durability, a polyfunctional monomer can be added. As this polyfunctional monomer, those exemplified as the monomer put in the microcapsule can be used. Among them, preferable monomers include trimethylolpropane triacrylate, pentaerythritol triacrylate, and the like. The addition amount of the polyfunctional monomer is preferably 0.1 to 10% by mass, and more preferably 0.5 to 5.0% by mass in the total solid content of the recording layer.
<Thermal polymerization inhibitor>
In the present invention, it is desirable to add a small amount of a thermal polymerization inhibitor in order to prevent unnecessary thermal polymerization of the ethylenically unsaturated compound during preparation or storage of the recording layer coating solution. Suitable thermal polymerization inhibitors 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-t-butylphenol), N-nitroso-N-phenylhydroxylamine aluminum salt and the like. The addition amount of the thermal polymerization inhibitor is preferably 0.01 to 5% by mass in the total solid content of the recording layer.
<Inorganic fine particles>
Inorganic fine particles may be added to the recording layer matrix according to the present invention, and suitable examples of inorganic fine particles include silica, alumina, magnesium oxide, titanium oxide, magnesium carbonate, calcium alginate, or a mixture thereof. Even if they are not photothermally convertible, they can be used for strengthening the film and enhancing interfacial adhesion by surface roughening.

  The average particle size of the inorganic fine particles is preferably 5 nm to 10 μm, more preferably 10 nm to 1 μm. Within this range, the microcapsules and the metal microparticles of the photothermal conversion agent are both stably dispersed in the hydrophilic resin, the film strength of the recording layer is sufficiently maintained, and the non-hydrophilic material has excellent hydrophilicity that does not easily cause printing stains. An image portion can be formed.

Such inorganic fine particles can be easily obtained as a commercial product such as a colloidal silica dispersion. The content of the inorganic fine particles in the recording layer is preferably 20% by mass or less, more preferably 10% by mass or less, based on the total solid content of the recording layer.
<Surfactant>
In the recording layer matrix according to the present invention, JP-A-2-195356, JP-A-59-121044, JP-A-4-12044 are used for improving the dispersion stability of the recording layer, plate making and printing performance, and coating properties. Nonionic, anionic, cationic, amphoteric or fluorine-based surfactants described in No. 13149 and Japanese Patent Application No. 2001-169731 can be added. A suitable addition amount of these surfactants is 0.005 to 1% by mass of the total solid content of the recording layer.
<Plasticizer>
In the recording layer matrix according to the present invention, a plasticizer can be added as needed to impart flexibility of the coating film. For example, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate and the like are used.
(Formation of image recording layer)
The recording layer according to the present invention is applied by preparing a coating solution by 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-butyrolactone, 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.

  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.

Although the recording layer coating amount (solid content) on the support obtained after coating and drying varies depending on the application, it is generally preferably 0.5 to 5.0 g / m ² . As the coating amount decreases, the apparent sensitivity increases, but the film properties of the recording layer that performs the image recording function tend to decrease.
[Overcoat layer]
The lithographic printing plate precursor according to the present invention is provided on the recording layer in order to protect the hydrophilic recording layer surface from contamination with lipophilic substances during storage and fingerprint trace contamination due to finger contact during handling. An overcoat layer containing a water-soluble resin described in JP-A-162961 and JP-A-2002-19318 can be provided.

  Specific examples of water-soluble resins used in the overcoat layer include natural gums such as gum arabic, water-soluble soybean polysaccharide, fiber derivatives (eg, carboxymethyl cellulose, carboxyethyl cellulose, methyl cellulose, etc.), modified products thereof, For synthetic polymers such as white dextrin, pullulan, and enzymatically degraded etherified dextrin, polyvinyl alcohol (polyvinyl acetate having a hydrolysis rate of 65% or more), polyacrylic acid, its alkali metal salt or amine salt, and polyacrylic acid Polymer, alkali metal salt or amine salt thereof, polymethacrylic acid, alkali metal salt or amine salt thereof, vinyl alcohol / acrylic acid copolymer and alkali metal salt or amine salt thereof, polyacrylamide, copolymer thereof, polyhydroxy Ethyl acrylate, Polyvinyl Lupyrrolidone, its copolymer, polyvinyl methyl ether, vinyl methyl ether / maleic anhydride copolymer, poly-2-acrylamido-2-methyl-1-propanesulfonic acid, its alkali metal salt or amine salt, poly-2 -Acrylamido-2-methyl-1-propanesulfonic acid copolymer, its alkali metal salt or amine salt. Depending on the purpose, two or more of these resins may be mixed and used. However, the present invention is not limited to these examples.

  The overcoat layer may contain a photothermal conversion agent in order to improve sensitivity. A preferable photothermal conversion agent includes a water-soluble infrared absorbing dye. For example, (IR-1) to (IR-11) shown in the description of the recording layer are preferably used.

  In addition, a nonionic surfactant can be mainly added to the overcoat layer in the case of aqueous solution coating for the purpose of ensuring the uniformity of coating. Specific examples of such nonionic surfactants include sorbitan tristearate, sorbitan monopalmitate, sorbitan trioleate, stearic acid monoglyceride, polyoxyethylene nonylphenyl ether, polyoxyethylene dodecyl ether and the like. . The proportion of the nonionic surfactant in the overcoat layer in the total solid is preferably 0.05 to 5 mass%, more preferably 1 to 3 mass%.

  Furthermore, the overcoat layer can contain a compound having any one of fluorine atoms and silicon atoms described in JP-A No. 2001-341448 in order to prevent sticking between plates during stacking and storage.

The thickness of the overcoat layer according to the present invention is preferably 0.1 to 4.0 μm, and more preferably 0.1 to 1.0 μm. Within this range, it is possible to prevent the recording layer from being contaminated by an oleophilic substance without impairing the removability of the overcoat layer on the printing press.
[Support]
The support that can be used for the lithographic printing plate precursor according to the present invention is a dimensionally stable plate-like material, for example, paper, paper laminated with plastic (for example, 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.), paper or plastic film on which the above metal is laminated or vapor-deposited. A preferable support is an aluminum plate.

  The aluminum plate is a pure aluminum plate and an alloy plate containing aluminum as a main component and containing a trace amount of different elements. Further, a plastic is laminated on a thin film of aluminum or an aluminum alloy. Examples of foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of foreign elements in the alloy is at most 10% by mass. Further, it may be an aluminum plate from an aluminum ingot using a DC casting method or an aluminum plate from an ingot by a continuous casting method. However, as the aluminum plate applied to the present invention, conventionally known and publicly available aluminum plates can be used as appropriate.

  The thickness of the substrate used in the present invention is 0.05 mm to 0.6 mm, preferably 0.1 mm to 0.4 mm, and particularly preferably 0.15 mm to 0.3 mm.

  Prior to using the aluminum plate, it is preferable to perform a surface treatment such as roughening the surface or anodizing. By the surface treatment, it is easy to improve hydrophilicity and secure adhesion to the recording layer.

  The surface of the aluminum plate is roughened by various methods. For example, a method of mechanically roughening, a method of electrochemically dissolving and roughening the surface, and a method of selectively dissolving the surface chemically. By the method. As the mechanical method, 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. As a chemical method, a method of immersing in a saturated aqueous solution of an aluminum salt of a mineral acid as described in JP-A No. 54-31187 is suitable. In addition, as an electrochemical surface roughening method, there is a method of performing alternating current or direct current in an electrolytic solution containing an acid such as hydrochloric acid or nitric acid. Further, as disclosed in JP-A-54-63902, an electrolytic surface roughening method using a mixed acid can also be used. The roughening by the method as described above is preferably performed in such a range that the center line average roughness (Ra) of the surface of the aluminum plate is 0.2 to 1.0 μm.

  The roughened aluminum plate is subjected to alkali etching treatment using an aqueous solution of potassium hydroxide or sodium hydroxide as necessary, and further neutralized, and then anodized to increase wear resistance as desired. Processing is performed.

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 treatment conditions for anodization vary depending on the electrolyte used, and thus cannot be specified in general. However, in general, the electrolyte concentration is 1 to 80% by mass solution, the liquid temperature is 5 to 70 ° C., and the current density is 5 to 60 A / day. dm ² , voltage 1 to 100 V, and electrolysis time 10 seconds to 5 minutes are suitable. The amount of the oxide film to be formed is preferably 1.0 to 5.0 g / m ² , particularly 1.5 to 4.0 g / m ² .

  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, an aqueous solution containing an anodized film micropore enlargement treatment, micropore sealing treatment, and a hydrophilic compound described in JP-A Nos. 2001-253181 and 2001-322365 The surface hydrophilization treatment to be immersed can be appropriately selected and performed.

  Suitable hydrophilic compounds for the hydrophilization treatment include polyvinylphosphonic acid, sulfonic acid group-containing compounds, saccharide compounds, citric acid, alkali metal silicates, potassium zirconium fluoride, phosphate / inorganic fluorine compounds, and the like. Can be mentioned.

  When using a support with insufficient surface hydrophilicity such as a polyester film as the support used in the present invention, it is desirable to apply a hydrophilic layer to make the surface hydrophilic. As the hydrophilic layer, at least one element selected from beryllium, magnesium, aluminum, silicon, titanium, boron, germanium, tin, zirconium, iron, vanadium, antimony and transition metal described in JP-A-2001-199175 is used. A hydrophilic layer formed by applying a coating solution containing an oxide or hydroxide colloid is preferred. Among these, a hydrophilic layer formed by applying a coating solution containing a silicon oxide or hydroxide colloid is preferable.

  In the present invention, before applying the recording layer, an inorganic undercoat layer such as a water-soluble metal salt such as zinc borate described in JP-A-2001-322365, or An organic subbing layer containing carboxymethylcellulose, dextrin, polyacrylic acid or the like can be provided. The undercoat layer can contain the photothermal conversion agent.

  By applying the lithographic printing plate precursor having such a configuration to the image forming method of the present invention, an image portion having sufficient strength is formed by image exposure using infrared rays. The printing durability of the printing plate precursor has been improved, and it has become possible to obtain a large number of high-quality printed materials.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these.
[Production of support]
Cleaning treatment was applied to molten metal of JIS A1050 alloy containing 99.5 mass% or more of aluminum and Fe 0.30 mass%, Si 0.10 mass%, Ti 0.02 mass%, and Cu 0.013 mass%. And cast. In the cleaning process, a degassing process was performed to remove unnecessary gases such as hydrogen in the molten metal, and a ceramic tube filter process was performed. The casting method was a DC casting method. The solidified 500 mm thick ingot was chamfered 10 mm from the surface and homogenized at 550 ° C. for 10 hours so as not to coarsen the intermetallic compound.

  Next, after hot rolling at 400 ° C. and intermediate annealing at 500 ° C. for 60 seconds in a continuous annealing furnace, cold rolling was performed to obtain an aluminum rolled plate having a plate pressure of 0.30 mm. By controlling the surface roughness of the rolling roll, the centerline average surface roughness Ra after cold rolling was controlled to 0.2 μm. Then, it applied to the tension leveler in order to improve planarity.

Next, a surface treatment for making a lithographic printing plate support was performed. First, in order to remove the rolling oil on the surface of the aluminum plate, degreasing treatment was carried out with a 10% by mass sodium aluminate aqueous solution at 50 ° C. for 30 seconds, and neutralization and smut removal treatment were carried out with a 30% by mass sulfuric acid aqueous solution at 50 ° C. for 30 seconds. Next, in order to improve the adhesion between the support and the recording layer and to provide water retention to the non-image area, a so-called graining treatment was performed to roughen the surface of the support. An aqueous solution containing 1% by mass of nitric acid and 0.5% by mass of aluminum nitrate is kept at 45 ° C., and an aluminum web is allowed to flow in the aqueous solution, while an indirect power feeding cell has a current density of 20 A / dm ² and a duty ratio of 1: 1. Electrolytic graining was performed by applying an anode side electric quantity of 240 C / dm ² in an alternating waveform. Thereafter, an etching treatment was performed with a 10% by mass aqueous sodium aluminate solution at 50 ° C. for 30 seconds, and a 30% by mass sulfuric acid aqueous solution was subjected to neutralization and smut removal treatment at 50 ° C. for 30 seconds. Furthermore, in order to improve wear resistance, chemical resistance and water retention, an oxide film was formed on the support by anodic oxidation. An anodization of 2.5 g / m ² by using a 20% by weight sulfuric acid aqueous solution as an electrolyte at 35 ° C. and carrying out an aluminum web through the electrolyte and performing an electrolytic treatment at a direct current of 14 A / dm ² by an indirect power supply cell. A film was created.

Thereafter, a silicate treatment was performed to ensure hydrophilicity as a non-image portion of the printing plate. The treatment was carried in such a way that a No. 3 sodium silicate 1.5 mass% aqueous solution was kept at 70 ° C. so that the contact time of the aluminum web was 15 seconds and further washed with water. The adhesion amount of Si was 10 mg / m ² . The center line surface roughness Ra of the support produced as described above was 0.25 μm.
[Synthesis of microcapsules encapsulating a cationically polymerizable compound]
As an oil phase component, 4.5 g of bis (vinyloxyethyl) ether of bisphenol A, an adduct of trimethylolpropane and xylylene diisocyanate (Takenate D-110N, manufactured by Mitsui Takeda Chemical Co., Ltd., microcapsule wall material) 5 g Millionate MR-200 (Nippon Polyurethane Co., Ltd. aromatic isocyanate oligomer, microcapsule wall material) 3.75 g, Infrared absorbing dye (IR-27 described herein) 1.5 g, Pionine A41C (Takemoto Yushi Co., Ltd.) ) Surfactant) 0.1 g was dissolved in 18.4 g of ethyl acetate. As an aqueous phase component, 37.5 g of a 4 mass% aqueous solution of PVA205 (Kuraray polyvinyl alcohol) was prepared. The oil phase component and the aqueous phase component were emulsified at 12000 rpm for 10 minutes using a homogenizer. Thereafter, a solution obtained by dissolving 0.38 g of tetraethylenepentamine (pentafunctional amine, microcapsule wall cross-linking agent) in 26 g of water was added, followed by stirring at 65 ° C. for 3 minutes while cooling with water. The microcapsule solution thus obtained had a solid content concentration of 24% by mass and an average particle size of 0.3 μm.
[Example 1]
(Preparation of lithographic printing plate precursor)
The following recording layer coating solution containing the microcapsules of the synthesis example was bar-coated on the aluminum substrate obtained in the above production example, and then dried in an oven at 100 ° C. for 60 seconds. A lithographic printing plate precursor of 0 g / m ² was prepared.
<Recording layer coating solution>
・ 35.4g of water
・ 9.0 g of microcapsule liquid in the above synthesis example
Acid generator (AI-7 as described herein) 0.24 g
(Exposure / printing and evaluation)
The lithographic printing plate precursor obtained above is irradiated with ultraviolet UV by the ultraviolet irradiation devices 38 and 120 in the image exposure apparatus 10 shown in FIG. 1 or the image exposure apparatus 100 shown in FIG. After a second, image exposure was performed with a Trend setter 3244VX manufactured by Creo equipped with a water-cooled 40 W infrared semiconductor laser under conditions of an output of 17 W, an outer drum rotation speed of 100 rpm, and a resolution of 2400 dpi. At this time, the wavelength of the ultraviolet rays UV irradiated by the ultraviolet irradiation devices 38 and 120 is set to 365 nm when the ultraviolet irradiation device 38 shown in FIG. 3 is used, and the ultraviolet irradiation device 120 shown in FIG. 5 is used. Is set to 375 nm, and the ultraviolet ray UV irradiated to the recording layer of the lithographic printing plate precursor 12 has an acid generator in the recording layer as long as it has a wavelength selected from a wavelength range of 200 nm to 400 nm. It is possible to effectively generate an acid. Moreover, the output of the ultraviolet rays UV emitted from the ultraviolet irradiation devices 38 and 120 is set within a range of 30W to 100W. As a result, not only in the vicinity of the surface of the recording layer but also in the vicinity of the interface between the recording layer and the support, sufficient starting species are supplied by promoting the decomposition reaction of the acid generator. Polymerization and curing reaction of the released cationic polymerizable compound proceeded efficiently, and a strong and excellent printing durability could be formed.

  After completion of image exposure, the lithographic printing plate precursor was attached to a cylinder of a printing machine SOR-M manufactured by Heidelberg without developing. 4% by volume IF102 (manufactured by Fuji Photo Film Co., Ltd.) and a fountain solution made by using Balius ink ink (manufactured by Dainippon Ink & Chemicals, Inc.) and supplying the fountain solution, supplying the ink, Further, paper was supplied for printing.

  At this time, the recording layer in the non-image area was removed in the initial stage of the printing process, and a high-quality printed matter without stains in the non-image area was obtained. After that, printing was continued, and the number of sheets was visually measured to determine whether the non-image area was free of smudges and the image area could be printed with a sufficient ink density, and used as an index of printing durability. The larger the number, the better the printing durability.

  As a result, 35,000 high-quality printed materials were obtained, and it was confirmed that the lithographic printing plate on which an image was formed by the method of the present invention had excellent printing durability that could withstand practicality. .

It is a side view which shows the structure of the image exposure apparatus of 1st Embodiment which concerns on this invention. It is a perspective view which shows the structure of the exposure head and its feed mechanism in the image exposure apparatus shown by FIG. It is a side view which shows the structure of the ultraviolet irradiation device in the image exposure apparatus shown by FIG. It is a side view which shows the structure of the image exposure apparatus of 2nd Embodiment which concerns on this invention. It is a perspective view which shows the modification of the ultraviolet irradiation device applicable to the image exposure apparatus which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image exposure apparatus 12 Planographic printing plate precursor 20 Outer drum (holding member)
26 Exposure head (exposure means)
28 Feeding mechanism (exposure means)
32 Light source device (exposure means)
38 UV irradiation equipment (UV irradiation means)
40 UV light source unit 42 integrator illumination optical system 44 UV lamp 100 image exposure apparatus 120 ultraviolet irradiation apparatus 122 semiconductor laser

Claims (4)

An image forming method for forming an image on a lithographic printing plate precursor comprising an image recording layer comprising a microcapsule encapsulating a cationically polymerizable compound, an acid generator, and a photothermal conversion agent on a support. There,
An ultraviolet irradiation step of generating an acid from an acid generator contained in the image recording layer by irradiating the entire surface of the image recording layer of the lithographic printing plate precursor with ultraviolet rays substantially uniformly;
An image exposure step of selectively exposing the lithographic printing plate precursor with infrared rays to form an image on the image recording layer of the lithographic printing plate precursor after completion of the ultraviolet irradiation step;
An image forming method comprising:   2. The image forming method according to claim 1, wherein in the ultraviolet irradiation step, the image recording layer of the lithographic printing plate precursor is irradiated with ultraviolet rays having a wavelength selected from a wavelength range of 200 nm to 400 nm. An image exposure apparatus used in the image forming method according to claim 1 or 2,
A holding member for holding the lithographic printing plate precursor, the lithographic printing plate precursor being mountable;
Ultraviolet irradiation means for irradiating the image recording layer of the lithographic printing plate precursor mounted on the holding member with ultraviolet rays;
Exposure means for selectively exposing the lithographic printing plate precursor held by the holding member with infrared rays to form an image on an image recording layer of the lithographic printing plate precursor;
An image exposure apparatus comprising:   The ultraviolet irradiation means includes an ultraviolet light source unit that emits ultraviolet light, and an integrator illumination optical system that irradiates the lithographic printing plate precursor with a uniform light amount distribution of the ultraviolet light emitted from the ultraviolet light source unit. Image exposure apparatus.

Images