JP2007033734A - Method for processing planographic printing plate, and automatic developing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for processing a planographic printing plate and an automatic developing apparatus in which a planographic printing plate having a photopolymerizable photosensitive layer using a high-definition screen upon image exposure can be developed for a long period of time without inducing image defects such as process irregularity. <P>SOLUTION: The method for processing a planographic printing plate and an automatic developing apparatus include steps of scanning and exposing a photosensitive planographic printing plate having a photopolymerizable photosensitive layer on a support to laser light and conveying the plate to a developing unit for developing, wherein a high-definition screen having ≥250 lines or more as an AM screen or having ≤50 μm minimum pixel size constituting dots as an FM screen is used for scanning exposure. When the photosensitive planographic printing plate 12 is conveyed to the developing unit 14, the carrying direction of the photosensitive planographic printing plate 12 is tilted at an angle of 30° to 60° with respect to a sub-scanning direction orthogonal to the main scanning direction during scanning exposure of the photosensitive planographic printing plate 12. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a processing method and an automatic developing device for a lithographic printing plate in which a photosensitive lithographic printing plate having a photopolymerizable photosensitive layer on a support is scanned and exposed by a laser and then conveyed to a development processing unit for development.

  In recent years, the development of lasers has been remarkable, and high-power and small-sized lasers have become readily available. These lasers are very useful as a recording light source when directly making a printing plate from digital data of a computer or the like.

  Ar ion laser (488 nm) or FD-YAG laser (532 nm) is used as a recording light source, and a photosensitive lithographic printing plate having a photopolymerizable photosensitive layer suitable for these light sources has been developed and put into practical use. . Recently, an InGaN-based semiconductor laser (violet laser, 350 nm to 450 nm) has been developed, and a bright room, lower cost of the exposure machine, and higher productivity are expected. The development of lithographic printing plates having a polymerizable photosensitive layer has been accelerated.

  Furthermore, in the plate making / printing industry, various screening printing with high definition can be put into practical use relatively easily by combining the above-mentioned technology that outputs halftone dots directly from data to the printing plate and the screening processing software. The situation has led to high-definition screens being widely used in conjunction with high-end printing orientation in the market. As high-definition screens, conventional AM screens include a screening method with more than 250 lines, FM type, and AM / FM hybrid type (see Non-Patent Document 1 below).

  In order to form a planographic printing plate, development processing is performed after recording on the printing plate by laser exposure. In general, an automatic developing device is used for developing a printing plate. As an automatic developing device, a device including steps including heating, pre-water washing, development, water washing, and finishing is widely used (Patent Document 1).

Journal of the Japan Printing Society, Vol. 40, No. 2 (2003) JP 2003-107728 A

  However, when a printing plate on which an image is recorded by laser exposure using a high-definition screen is developed, uneven processing due to the scanning direction of the laser exposure and the scraping direction of the developing brush occurs, resulting in image defects. There was a case.

  The present invention has been made based on the background as described above. An object of the present invention is to provide a processing method and an automatic developing device for a lithographic printing plate, which can develop a lithographic printing plate having a photopolymerizable photosensitive layer using a high-definition screen in image exposure without causing image defects such as processing unevenness over a long period of time. Is to provide.

  As a result of intensive studies, the present inventors have found the following matters. The halftone dot portion of a lithographic printing plate having a photopolymerizable photosensitive layer that uses a high-definition screen for image exposure has a larger or smaller halftone dot number than the halftone dot portion of an AM screen of about 175 lines that has been conventionally used. Therefore, since the perimeter of the halftone dot per unit area (the boundary length between the image portion and the non-image portion) is long, there are many portions called fringes. The fringe portion is a boundary between the portion to be developed and the remaining portion, and therefore contains some insoluble matter that is not dissolved or dispersed in the developer. For this reason, it has been found that the insoluble portion at the boundary portion, which was not a problem in the conventional AM screen of the halftone dot size, is likely to be uneven in processing on the high-definition screen, resulting in image defects.

  Further, it was found that when the focus shift at the time of exposure and the development unevenness overlap, the processing unevenness is further deteriorated. For example, as an exposure apparatus for a lithographic printing plate, an internal drum type exposure apparatus 400A that performs scanning exposure using a spinner 403 that has an inclined mirror 401 at the shaft tip as shown in FIG. There is 400B. In the exposure apparatuses 400A and 400B, the spinner 403 is rotated at a high speed while irradiating the inclined mirror 401 of the spinner 403 with high speed, thereby scanning and exposing the printing plate 12 arranged on the inner periphery of the drum with the reflected laser beam. 6A is a schematic configuration diagram showing the configuration of a single laser exposure apparatus in which the laser device 405 is one, and FIG. 6B is a schematic configuration diagram showing the configuration of two twin laser exposure apparatuses in which the laser device 405 is two.

  In the exposure processing in the exposure apparatus having the above-described configuration, the spinner 403 rotates at high speed and writes on the printing plate 12, so that patterning is performed as stripes even if the writing position is slightly shifted. Furthermore, if the temperature distribution of the air near the spinner is different, a so-called fluctuation occurs, and the exposure position of the printing plate 12 is changed. The present inventor has found that when the positional deviation at the time of exposure and the unevenness at the time of development overlap in a specific direction, the processing unevenness is remarkably deteriorated.

  As a result of further intensive studies, the present inventor has determined that the angle at which the lithographic printing plate is inserted into the development processing section after exposure of the lithographic printing plate comprising a high-definition screen is determined in the main scanning direction Da and the sub-scanning direction Db during exposure. 7, as shown in FIG. 7, the unevenness at the time of exposure and the unevenness at the time of development can be processed without overlapping by inserting and developing with a predetermined angle θa to θb with respect to these directions. It has been found that stable processing can be performed with little processing unevenness and no image defects over a long period of time.

That is, the above object of the present invention is achieved by the following configuration.
(1) A processing method of a lithographic printing plate in which a photosensitive lithographic printing plate having a photopolymerizable photosensitive layer on a support is subjected to scanning exposure with a laser and then transported to a development processing unit for development. When the photosensitive lithographic printing plate is transported in the development processing unit using a high-definition screen having 250 lines or more as the AM screen and a minimum pixel size of 50 μm or less as the FM screen as the FM screen. In addition, the conveyance direction of the photosensitive lithographic printing plate and the sub-scanning direction orthogonal to the main scanning direction during the scanning exposure of the photosensitive lithographic printing plate are inclined within a range of 30 to 60 degrees. How to process lithographic printing plates.

(2) The processing of a lithographic printing plate according to (1), wherein the photosensitive lithographic printing plate is inserted with an inclination in the range when the photosensitive lithographic printing plate is inserted into the development processing section. Method.

(3) An automatic development apparatus for a lithographic printing plate in which a photosensitive lithographic printing plate having a photopolymerizable photosensitive layer on a support is subjected to scanning exposure with a laser and then transported to a development processing section for development. In addition, a high-definition screen having 250 lines or more as an AM screen and a minimum pixel size constituting a halftone dot of 50 μm or less is used as an FM screen, and the photosensitive lithographic printing plate is conveyed to the development processing unit. In the middle of the conveyance path, the conveyance direction of the photosensitive lithographic printing plate and the sub-scanning direction orthogonal to the main scanning direction during the scanning exposure of the photosensitive lithographic printing plate are inclined within a range of 30 to 60 degrees. An automatic developing device for a lithographic printing plate, comprising a printing plate rotating and conveying means.

  Here, the inclination angle is preferably 35 to 55 degrees, more preferably 40 to 50 degrees. More preferably, it is 45 degrees. Further, the place where the transport direction of the planographic printing plate is different from the scanning direction at the time of scanning exposure after exposure may be any place as long as it is before development. When the processing of the lithographic printing plate is a process comprising heating, pre-water washing, development, water washing, and finishing, it is inserted at different angles before heating, pre-water washing, or before development. In the process consisting of development, washing and finishing, the angle is changed before development.

  As high-definition screens, conventional AM screens include a screening method that exceeds 250 lines, an FM type, and an AM / FM hybrid type.

  The AM high-definition screen corresponds to 250 lines or more, but a Co-Re screen manufactured by Fuji Photo Film Co., Ltd. can be suitably used.

FM screens include Fuji Photo Film's FM screen TAFFETA (20), CREO's Staccato (10, 20, 25, 35, 36), Dainippon Screen's Randot, RandotX (10, 15, 20) Stain Screening manufactured by Heidelbelg and Cristal Raster manufactured by Agfa can be used.
As hybrid screens, Dainippon Screen's Fairdot and Agfa's Sublima are known.

  Specifically, there are AM screens of 250 lines or more, FM screens described above, and hybrid screens. In the FM screen and the hybrid screen, when the size of the minimum pixel constituting the halftone dot is 50 μm or less, image unevenness is likely to occur. In particular, when the size is 30 μm or less, image unevenness is more likely to occur, and the present invention is effective. .

  The present invention is a processing method and a processing apparatus for a lithographic printing plate in which a photosensitive lithographic printing plate having a photopolymerizable photosensitive layer on a support is scanned and exposed by a laser and then transported to a development processing section for development. When the photosensitive lithographic printing plate is conveyed in the development processing section, the conveyance direction of the photosensitive lithographic printing plate and the sub-scanning direction orthogonal to the main scanning direction at the time of scanning exposure of the photosensitive lithographic printing plate are changed from 30 degrees to 60 degrees. By inclining within the range of degrees, the unevenness at the time of exposure and the unevenness at the time of development can be processed without overlapping, and there is an excellent effect that stable processing without image defects can be performed for a long time with little processing unevenness.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
As the automatic developing apparatus used in the present invention, any apparatus can be used as long as it includes heating, pre-water washing, development, water washing and finishing steps. A planographic printing plate processing method and an automatic developing apparatus according to the present invention will be described below with reference to the drawings.

  1 and 2 show a basic configuration of an automatic developing apparatus according to the present embodiment. The automatic developing apparatus 1 includes a preprocessing unit 200 shown in FIG. 1 and a development processing unit 10 shown in FIG. Further, if necessary, a rotary conveyance unit 300 as a printing plate rotation conveyance unit is provided in the middle of a conveyance path for conveying the development processing unit 10.

First, the rotary conveyance unit 300 will be described.
The rotary conveyance unit 300 has a printing plate 12 scanned and exposed by a laser in a predetermined angular range in a sub-scanning direction orthogonal to the main scanning direction at the time of scanning exposure of the printing plate 12 with respect to the conveyance direction of the printing plate 12. It is a mechanism for inclining. That is, since the main scanning direction at the time of scanning exposure of the printing plate 12 is often the width direction of the printing plate 12, the rotary conveyance unit 300 sets the longitudinal direction perpendicular to the width direction of the printing plate 12 to the conveyance direction. Will be inclined. The predetermined angle range may be in the range of 30 degrees to 60 degrees, preferably 35 degrees to 55 degrees, and more preferably 40 degrees to 50 degrees. The inclination angle may be an angle in either positive or negative direction.

  FIGS. 3A and 3B are configuration diagrams showing a configuration example of the rotary conveyance unit, in which FIG. 3A is a plan view and FIG. The rotary conveyance unit 300 shown here includes an inlet-side conveyance roller 301 that nips the printing plate 12 inserted on the inlet side, an outlet-side conveyance roller 303 that carries out the printing plate 12 on the outlet side, and an inlet side. Between the conveyance roller 301 and the exit-side conveyance roller 303, there is a rotary conveyance roller unit 307 in which a plurality of lower rollers 305 are arranged.

  In the rotary conveyance roller unit 307, the direction orthogonal to the conveyance direction of the printing plate 12 is the axial direction of the lower roller 305 on the entrance side, and the direction inclined from the conveyance direction is the axial direction of the lower roller 305 on the exit side. ing. Due to the arrangement of the lower rollers 305 that are gradually inclined in this manner, the printing plate 12 rotates by an angle θ with respect to the transport direction as it is transported.

  When the printing plate 12 is inserted in parallel with the transport direction by the rotary transport unit 300, it is transported while being inclined at a predetermined angle θ on the exit side. And the printing plate 12 carried out from the rotation conveyance part 300 is carried in in the state inclined to the pre-processing part 200 of a back | latter stage.

  In the present embodiment, the configuration including the rotary conveyance unit 300 will be described. However, the configuration is not limited thereto, and the printing plate 12 may be manually supplied to the conveyance path while being inclined within the predetermined angle range. In that case, the rotary conveyance unit 300 becomes unnecessary. That is, as long as the printing plate 12 that has reached the development processing unit 10 is inclined within the predetermined angle range, the printing plate 12 may be inclined by any means. In addition, the configuration of the rotary conveyance unit 300 is not limited thereto, and can be changed to any other mechanism without departing from the gist of the present invention.

Next, the preprocessing unit 200 will be described.
In the pretreatment unit 200, a pre-heating treatment and a pre-water washing treatment are performed on the planographic printing plate (hereinafter also referred to as a printing plate) 12 prior to the development treatment. The printing plate 12 pre-processed by the pre-processing apparatus 200 is developed by the development processing unit 10, and the development processing unit 10 uses an arbitrary configuration capable of developing the printing plate 12. it can. Further, the pre-processing unit 200 applied to the present embodiment may be used separately from the development processing unit 10 or may be used by being connected to the development processing unit 10.
Further, the pre-processing unit may be eliminated and processing may be performed only by the developing unit.

  In the pretreatment apparatus 200, a preheating unit 204 is provided in the machine frame 202 on the upstream side in the conveying direction of the printing plate 12, and a prewater washing unit 206 as a prewater washing step is provided on the downstream side.

  In the pre-heating unit 204, a plurality of (three in FIG. 1) skewer rollers 210 are arranged in the heating chamber 208. In the heating chamber 208, a heater 214 is provided on the inlet 212 side, and a circulation fan 216 is provided on the upstream side of the heater 214.

  In the preheating unit 204, when the printing plate 12 passes through the heating chamber 208, the photopolymerizable photosensitive layer of the printing plate 12 is accurately cured so as to have a predetermined temperature and a predetermined heating time, The printing durability of the printing plate 12 is increased.

  On the other hand, the printing plate 12 that has passed through the heating chamber 208 is sent from the outlet 218 to the pre-water washing section 206.

  The pre-rinsing section 206 is provided with a water washing tank 220, and a washing tank 222 for storing washing water is formed in the water washing tank 220.

  In the pre-water washing unit 206, the conveyance rollers 224, 226, and 228 are arranged in a staggered manner along the conveyance direction of the printing plate 12 on the pre-heating unit 204 side. The conveyance rollers 224 and 228 are provided so as to face the upper surface of the printing plate 12, and the conveyance roller 226 is disposed between the conveyance rollers 224 and 228 so as to face the lower surface of the printing plate 12.

  As a result, the printing plate 12 sent to the pre-water washing unit 206 is transported between the transport rollers 224 and 228 and the transport roller 226.

  In the pre-water washing section 206, a brush roller 230 and a backup roller 232 are provided in pairs in the vertical direction on the downstream side of the conveying roller 228. The contact position between the brush roller 230 and the backup roller 232 is lower than the lower end of the transport roller 228. As a result, the printing plate 12 is inclined from between the conveying rollers 226 and 228 and fed between the brush roller 230 and the backup roller 232.

  Further, the pre-water washing unit 206 is provided with a spray pipe 234 between the conveying roller 228 and the brush roller 230, and a spray pipe 236 is provided above the brush roller 230.

  The cleaning water ejected from the spray pipe 236 is supplied to the entire area along the axial direction of the brush roller 230, and the cleaning water is supplied to the brush material substantially uniformly. Then, the printing plate 12 is brushed by the brush roller 230 to which cleaning water is supplied.

  As a result, the printing plate 12 is fed between the brush roller 230 and the backup roller 232 in a state where the cleaning water is supplied to the surface and the cleaning water is accumulated.

  The protective layer provided on the printing plate 12 is easily swollen by washing water and easily peeled off. Therefore, the printing plate 12 is brushed by the brush roller 230 in a state where cleaning water is accumulated on the surface, the protective layer is surely removed, and the protective layer remains partially. It does not cause uneven development.

  The brush roller 230 is configured to obtain a predetermined brush pressure when the printing plate 12 is sandwiched between the backup roller 232 and the printing roller 12. As a result, when the printing plate 12 passes between the brush roller 230 and the backup roller 232 while rotating in a predetermined direction, the surface of the printing plate 12 is brushed by the brush roller 230.

  On the other hand, a skewer roller 238 is provided in the pre-wash unit 206 on the downstream side of the brush roller 230. The skewer roller 238 is arranged on the upper side of the conveying path of the printing plate 12, and the printing plate 12 that has passed between the brush roller 230 and the backup roller 232 is lifted by being brushed by the brush roller 230. , To prevent the transfer path from coming off.

  Further, when the preprocessing unit 200 is connected to the development processing unit 10, the transport roller pair 42 of the development processing unit 10 is in a state in which the planographic printing plate 12 can be transported to the most downstream side of the pre-water washing unit 206. Is provided.

Next, the development processing unit 10 of the automatic developing apparatus 1 will be described.
As shown in FIG. 2, the automatic developing device 1 is applied to the development processing of a lithographic printing plate having a photopolymerizable photosensitive layer image-exposed by an exposure device (not shown).

  The printing plate 12 developed by the automatic developing device 1 of the present embodiment is a plate in which a photosensitive layer is formed on a support surface of a thin plate using aluminum or the like via an adhesive layer, and a protective layer is provided thereon. is there.

  As shown in FIG. 2, the development processing unit 10 of the automatic developing device 1 supplies a developing unit 14 for processing the printing plate 12 with a developing solution and water for washing the printing plate 12 processed with the developing solution. A washing unit 16 for washing with water, a finishing treatment unit 18 for applying a gum solution for protecting the plate surface to the printing plate 12 after washing with water and desensitizing it, and a drying unit 20 for drying the printing plate 12 are provided. ing. That is, in the automatic developing device 1, a developing process, a washing process, a finishing process, and a drying process are sequentially arranged along the direction in which the printing plate 12 is conveyed (arrow A in FIG. 2).

  A processing tank 22 is provided in the development processing unit 10. In the processing tank 22, a developing tank 24 is formed at a position serving as the developing section 14 as a processing tank, and a washing tank 26 and a finishing processing tank 28 are formed at positions serving as the washing section 16 and the finishing processing section 18. Further, the processing tank 22 is provided with a space for the insertion section 34 on the upstream side of the developing tank 24 (upstream in the transport direction of the printing plate 12), and a space for the drying section 20 is formed on the downstream side of the finishing processing tank 28. Has been.

  In the outer panel 30 covering the periphery of the processing tank 22, a slit-like insertion port 32 is formed on the insertion side of the printing plate 12 into the development processing unit 10 (left side in FIG. 1). An insertion portion 34 is formed on the insertion port 32 side of the developing portion 14.

  The development processing unit 10 is provided with covers 36 and 38 that cover the upper part of the processing tank 22 and the upper part of the drying unit 20. The cover 36 on the insertion port 32 side covers the upper part of the washing unit 16 from the insertion part 34 of the processing tank 22, and the cover 38 is disposed so as to cover between the upper part of the washing unit 16 and the upper part of the drying unit 20.

  The cover 36 is provided with a reentry insertion port (sub-insertion port) 40 for inserting the printing plate 12 between the developing unit 14 and the water washing unit 16. The sub insertion port 40 is used for inserting the printing plate 12 for processing by the PS plate processor excluding the processing in the developing unit 14.

  A rubber conveyance roller pair 42 is disposed in the insertion portion 34 adjacent to the insertion port 40. The printing plate 12 on which the image has been printed is inserted between the conveyance roller pair 42 by being inserted along the direction of arrow A from the insertion port 32.

The conveyance roller pair 42 is rotationally driven, and sends the printing plate 12 to the developing unit 14 at an angle in a range of about 15 ° to 31 ° with respect to the horizontal direction while drawing the printing plate 12 from the insertion port 32. At this time, the front end side of the printing plate 12 in the transport direction is inclined by a predetermined angle with respect to the direction orthogonal to the transport direction. That is, the angle formed by the sub-scanning direction during scanning exposure of the printing plate 12 and the conveyance direction of the printing plate 12 is inclined within a range of 30 degrees to 60 degrees.
In the development processing unit 10 used for processing the single-sided type printing plate 12, the photosensitive layer (photosensitive surface) is inserted from the insertion port 32 with the photosensitive layer (photosensitive surface) facing upward. That is, the printing plate 12 is processed by the development processing unit 10 with the photosensitive surface facing upward.

  The developing tank 24 formed in the processing tank 22 has a substantially mountain shape with the bottom center protruding downward, and stores a developing solution for performing the developing processing of the printing plate 12. The immersion time is 2 to 60 seconds, preferably 5 to 30 seconds. The immersion temperature is preferably 15 to 50 ° C, more preferably 15 to 45 ° C, and further preferably 20 to 40 ° C.

  In the developing tank 24, a transport roller 48 is disposed on the insertion portion 34 side that is the upstream portion of the transport path of the printing plate 12. In the developing tank 24, a conveyance roller pair 50 is arranged at the center of the conveyance path of the printing plate, and a conveyance roller pair 52 is arranged on the washing unit 16 side which is a downstream part.

  A guide 116 is provided between the transport roller 48 and the transport roller pair 50 in the developing tank 24 of the development processing unit 10. One end of the guide 116 faces the conveyance roller 48, and the other end is directed between the conveyance roller pair 50.

  The printing plate 12 drawn into the development processing unit 10 by the conveying roller pair 42 is sent between the conveying roller 48 and the guide 116 and guided and conveyed on the guide 116 to the conveying roller pair 50.

  In the developing tank 24, a brush roller 141 is disposed in the vicinity of the conveyance roller pair 50 so as to face the guide 116. The brush roller 141 is a long cylindrical member that is driven to rotate about a rotation axis at a predetermined rotation direction and a predetermined rotation speed, and is placed on the surface of the exposure surface of the printing plate 12 conveyed on the guide 116. The contact is brushed by rubbing the upper surface of the printing plate 12. The guide 116 is disposed so that the brush roller 141 contacts the upper surface of the printing plate 12 with a predetermined brush pressure.

  Further, the brush roller 141 protrudes from the liquid surface of the developing solution, and the upper portion protruding from the liquid surface of the brush roller 141 enters the concave portion 100B of the shielding lid 100 together with the conveying roller pair 50. It has become.

  In the developing tank 24, a brush roller 142 is disposed between the conveyance roller pair 50 and 52. The brush roller 142 can have the same configuration as the brush roller 141, and is attached so as to face the upper surface side of the printing plate 12 conveyed between the conveyance roller pair 50, 52. The brush roller 142 is brushed by rubbing the photosensitive layer on the upper surface side of the printing plate 12 by contacting the upper surface of the printing plate 12 while rotating in a predetermined direction and a predetermined rotation direction, and unnecessary photosensitivity by the developer. It is intended to facilitate the removal of the layer. A transport roller 60 is disposed in the vicinity of the brush roller 142 in the downstream side in the transport direction of the printing plate 12. The conveyance roller 60 is attached so as to face the upper surface side of the printing plate 12 conveyed between the conveyance roller pair 50 and 52.

  The printing plate 12 drawn from the insertion port 32 by the conveyance roller pair 42 passes below the conveyance roller 48 and is rubbed and brushed by the brush roller 141, and then is fed between the conveyance roller pair 50. Then, the printing plate 12 is guided obliquely upward toward the conveyance roller pair 52 along the bottom surface of the developing tank 24 by the conveyance roller 50. At this time, the upper surface side of the printing plate 12 is rubbed and brushed by the brush roller 142.

In the present embodiment, the brush roller 141 and the brush roller 142 function as a rubbing member that removes the photopolymerizable photosensitive layer in the unexposed area by rubbing the exposed surface of the lithographic printing plate 12 after exposure.
A backup roller is provided on the opposite side of the brush roller 141 across the printing plate 12. A backup plate 46 is disposed on the opposite side of the brush roller 142 across the printing plate 12.

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

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

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

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

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

  As the Molton roller, a roller part 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.

  When a rotating member is used as the rubbing member, the number of revolutions of the rubbing member is preferably as fast as possible in order to improve the removability of the photopolymerizable photosensitive layer, but the durability of the automatic processor, the manufacturing cost, From the viewpoint of scattering of the developer and damage to the exposed portion of the lithographic printing plate precursor, 30 to 500 rpm, more preferably 50 to 300 rpm is preferable.

  When using a brush as a rubbing member, the number of the brush should just be one or more, and may have two or more.

  As the material of the brush used for the rubbing member, 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 is not particularly limited, but is preferably 0.01 mm to 1.0 mm, and more preferably 0.02 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 lithographic printing plate precursor 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.

  In the automatic developing apparatus 1 of the present embodiment, the brush rollers 141 and 142 that are rubbing members can switch the rotation direction between normal rotation and reverse rotation about the rotation axis, and one brush roller is set to normal rotation. Sometimes the other brush roller can be reversed. Further, when three or more brush rollers are applied as the rubbing member, at least one of the brush rollers is rotated in the reverse direction.

  The conveyance roller pair 52 provided on the downstream side in the conveyance direction in the developing unit 24 is formed, for example, by a rubber roller at the outer peripheral portion.

  In the developing tank 24, a spray pipe 56 is provided in the vicinity of the bottom surface between the conveyance roller pair 50 and the conveyance roller pair 52. The spray pipe 56 is supplied with the developer in the developing tank 24 sucked by a pump (not shown), and the developer is ejected from the spray pipe 56. Thereby, the developing solution in the developing tank 24 is agitated, and the printing plate 12 can be uniformly processed.

  After the photopolymerizable photosensitive layer is removed by the brush rollers 141 and 142, the printing plate 12 is pulled out from the developing tank 24 while being sandwiched by the transport roller pair 52. The printing plate 12 drawn from the developing tank 24 by the transport roller pair 52 is sent to the washing unit 16 while the developer attached to the surface is squeezed out by the transport roller pair 52.

  In the washing section 16, a conveyance path for conveying the printing plate 12 in a substantially horizontal state is formed by a pair of conveyance rollers 62 and 64 disposed above the washing tank 26. , 64 and horizontally transported above the washing tank 26.

  In the water washing section 16, spray pipes 66 and 68 are provided between a pair of conveyance rollers 62 and 64, with the conveyance path of the printing plate 12 being sandwiched up and down. The spray pipes 66 and 68 are arranged in the axial direction along the width direction of the printing plate 12 (a direction orthogonal to the conveying direction), and a plurality of discharge holes (not shown) facing the conveying path of the printing plate 12 are arranged in the axial direction. It is formed along.

  In the washing tank 26, for example, water (hereinafter referred to as “washing water”) is stored as a cleaning agent. In the automatic developing device 10, a spray pipe is synchronized with the conveyance of the printing plate 12 by a water supply pump (not shown). The flush water in the flush tank 26 is supplied to 66 and 68. As a result, washing water is ejected from the spray pipes 66 and 68 toward the printing plate 12 to wash away the developer adhering to the surface of the printing plate 12.

  The washing water supplied to the printing plate 12 is squeezed from the front and back surfaces of the printing plate 12 together with the developer and the like adhering to the front and back surfaces of the printing plate 12 when the printing plate 12 is held between the conveying roller pair 64 and sent out. It is dropped and collected in the washing tank 26. The spraying direction of the washing water from the spray pipes 66 and 68 is such that the spray pipe 66 is on the upstream side in the conveyance direction of the printing plate 12 and the spray pipe 68 is on the downstream side in the conveyance direction of the printing plate 12. It may be in another direction. Further, a new washing water solution is supplied to the washing tank 26 by means (not shown) according to the processing amount of the printing plate 12.

  In the water washing section 16, a brush for brushing the plate surface of the printing plate 12 may be disposed between the conveying roller pairs 62 and 64.

  The finishing processing unit 18 is provided with a conveying roller pair 70 above the finishing processing tank 28, and the printing plate 12 is conveyed toward the conveying roller pair 70 by the conveying roller pair 64, whereby the finishing processing unit 18 Is conveyed by the conveying roller pair 70 and sent toward the drying unit 20.

  The finishing processing unit 18 is provided with a spray pipe 72 above the transport path of the printing plate 12 and a spray pipe 74 below the transport path. The spray pipes 72 and 74 have a longitudinal direction (axial direction) along the width direction of the printing plate 12, and are arranged above and below the conveyance path of the printing plate 12. A plurality of discharge holes are formed in the spray pipes 72 and 74 along the width direction of the printing plate 12.

  The finishing treatment tank 28 stores a gum solution used for protecting the printing plate 12. The gum solution is supplied to the spray pipes 72 and 74 in synchronization with the conveyance of the printing plate 12. The spray pipe 72 drops the gum solution onto the printing plate 12 and spreads it on the surface of the printing plate 12 and applies it. The spray pipe 74 discharges the gum solution from the discharge hole toward the back surface of the printing plate 12 and applies the gum solution to the back surface of the printing plate 12.

  The printing plate 12 has a protective film formed by a gum solution applied to the front and back surfaces. In addition, the discharge direction of the gum solution from the spray pipe 72 is not limited to the downstream side in the transport direction of the printing plate 12, and may be other directions, and a rectifying plate is provided and ejected toward the rectifying plate. The gum solution may be applied to the surface of the printing plate 12 while being uniformly diffused along the width direction of the printing plate 12 with a current plate. Further, instead of the spray pipe 74, a discharge unit for applying the gum solution to the back surface of the printing plate 12 by moving the printing plate 12 in contact with the discharged gum solution may be used.

  The finishing processing unit 18 is provided with a cleaning spray 76 above the conveying roller pair 70, and a cleaning roller 78 that rotates while contacting the rollers above the conveying roller pair 70. At a predetermined timing, the cleaning water is dropped from the cleaning spray 76 to the contact position between the cleaning roller 78 and the roller above the conveying roller pair 70 via the rectifying plate 80, so that the cleaning water is supplied to the conveying roller pair 70. The gum solution is uniformly diffused on the peripheral surfaces of the upper rollers, and the gum solution is washed away from the peripheral surfaces of the upper and lower rollers of the conveying roller pair 70. The gum solution adheres to the peripheral surfaces of the rollers and damages the photopolymer plate 12. To prevent.

  The printing plate 12 to which the gum solution has been applied by the finishing processing unit 18 is sandwiched between the conveying roller pair 70, and the gum solution remains on the front and back surfaces slightly (the gum solution remains as a thin film) to the drying unit 20. Sent.

  In the development processing unit 10, a partition plate 82 is provided between the finishing processing unit 18 and the drying unit 20. The partition plate 82 is disposed above the conveying path of the printing plate 12 so as to face the upper end of the processing tank 22, and thereby, a slit-shaped insertion port is provided between the finishing processing unit 18 and the drying unit 20. 84 is formed. The partition plate 82 has a double structure, whereby a groove-like air passage is formed on the drying portion 20 side of the insertion opening 84, and the air in the drying portion 20 enters the air passage. Thus, the air in the drying unit 20 is prevented from entering the finishing processing unit 18 from the insertion port 84.

  In the drying unit 20, a support roller 86 that supports the printing plate 12 is disposed in the vicinity of the insertion port 84, and in the vicinity of the central portion in the conveyance direction of the printing plate 12 and the discharge port 88. A roller pair 90 and a conveying roller pair 92 are disposed. The printing plate 12 is transported in the drying unit 20 by a support roller 86 and transport roller pairs 90 and 92.

  Ducts 94 and 96 are disposed between the support roller 86 and the conveyance roller pair 90 and between the conveyance roller pair 90 and the conveyance roller pair 92 in pairs with the conveyance path of the printing plate 12 interposed therebetween. The ducts 94 and 96 are disposed such that the longitudinal direction thereof is along the width direction of the printing plate 12, and a slit hole 98 is provided on a surface facing the conveyance path of the printing plate 12.

  The ducts 94 and 96 discharge the dry air from the slit hole 98 toward the conveying path of the printing plate 12 when the dry air generated by the dry air generating means (not shown) is supplied from one end side in the longitudinal direction. And sprayed onto the printing plate 12. Thereby, as for the printing plate 12, the gum liquid currently apply | coated to the front and back is dried, and a protective film is formed.

  The printing plate 12 on which the protective film is formed is nipped by the conveying roller pair 92 and is carried out of the development processing unit 10.

  Here, the development processing unit 10 described above will be further described. In the development processing unit 10, the liquid level lid 100 is disposed in the development tank 24, so that the developer in the development tank 24 becomes carbon dioxide gas in the air. It is intended to prevent deterioration and moisture evaporation due to contact. A blade-shaped shielding member (not shown) formed of silicon rubber or the like is provided between the shielding lid 100 and the processing tank 22 and the conveying roller 48 or the conveying roller pair 52, so that the developer in the developing tank 24 is fresh. It may be possible to prevent contact with outside air or evaporation of water in the developer, which is more preferable.

  Furthermore, a preservative may be automatically added to the pre-wash water and the wash water in order to suppress the growth of scales and fungi. As a scale inhibitor, BK-3 manufactured by Fuji Photo Film Co., Ltd. is preferably used. As addition amount, it is 50-5000 ppm, Preferably it is 100-3000 ppm.

  The AM high-definition screen corresponds to 250 lines or more, but a Co-Re screen manufactured by Fuji Photo Film Co., Ltd. can be suitably used.

  As the FM screen, for example, Fuji Photo Film FM screen TAFFETA (20), CREO Staccato (10, 20, 25, 35, 36), Dainippon Screen Randot, RandotX (10, 15, 20), Stain Screening manufactured by Heidelbelg, and Cristal Raster manufactured by Agfa can be used.

  As hybrid screens, Dainippon Screen's Fairdot and Agfa's Sublima are known. Specifically, there are AM screens of 250 lines or more, more preferably 300 lines or more, FM screens described above, and hybrid screens. In the FM screen and the hybrid screen, when the size of the minimum pixel constituting the halftone dot is 50 μm or less, image unevenness is likely to occur. In particular, when the size is 30 μm or less, image unevenness is likely to occur, and the present invention is effective.

  Here, the size of the minimum pixel represents the length of one side of the minimum pixel constituting the image. FIG. 4 shows a highlight portion of the FM screen. FIG. 5 shows an FM screen halftone. As shown in FIGS. 4 and 5, the minimum pixel is visible on the highlight side, and can also be visually recognized on the halftone and part of the shadow portion side.

  Thus, the lithographic printing plate processing method and the automatic developing apparatus according to the present invention scan and expose a photosensitive lithographic printing plate having a photopolymerizable photosensitive layer on a support to a development processing unit 10. When developing, a high-definition screen having 250 lines or more as an AM screen and a minimum pixel size constituting a halftone dot of 50 μm or less is used as the FM screen as the printing plate 12. When the printing plate 12 is conveyed in the development processing unit 10, the conveyance direction of the printing plate 12 and the sub-scanning direction orthogonal to the main scanning direction at the time of scanning exposure of the printing plate 12 are 30 degrees to 60 degrees. The range is inclined. By inclining in this way, it is possible to perform processing without causing unevenness during exposure and unevenness during development, and it is possible to obtain an excellent effect that stable processing can be performed with little processing unevenness and no image defects over a long period of time.

  In other words, when the exposure conditions of the printing plate 12 are uneven in the distribution of the environmental temperature of the exposed portion and the exposure conditions such as the shift of the writing position are changed, the printing plate 12 has a pattern like stripes along the scanning direction. May occur. Further, if the printing plate 12 is scraped in one direction with a developing brush or the like during the development process, uneven development may occur along the scraping direction. In the past, since the inclination with respect to the transport direction of the printing plate 12 was not taken into consideration, the stripe unevenness and the development unevenness overlapped, and unevenness at a level that could be easily recognized was generated. However, according to the processing method of the present invention, when transporting in the development processing section, the transport direction of the printing plate and the sub-scanning direction at the time of scanning exposure of the printing plate are inclined within a range of 30 to 60 degrees. Therefore, the streak unevenness and the development unevenness do not overlap to become a stronger unevenness component, and stable processing without image defects becomes possible.

In addition, the place where the rotary conveyance unit 300 is arranged or the place where the exposed printing plate 12 is manually inserted into the conveyance path may be any place as long as the printing plate 12 is not developed. When the processing of the printing plate 12 is a process comprising heating, pre-water washing, development, water washing, and finishing, it may be before heating, pre-water washing, or before development, and the process comprising development, water washing, and finishing. In this case, it may be before development.
Moreover, when changing the inclination angle with respect to the conveyance direction of the printing plate 12, a mechanism may be provided in each step for inclining the printing plate 12 once inserted into the conveyance path to a different angle in each step while being conveyed. According to this, the occurrence of processing unevenness can be further reduced.

Next, the plate making of the photosensitive lithographic printing plate used in the present invention will be supplemented below.
The photosensitive lithographic printing plate used in the present invention has a photopolymerizable photosensitive layer on a support. Further, an undercoat layer may be provided between the support and the photopolymerizable photosensitive layer as necessary, and a protective layer (oxygen blocking layer) may be provided on the photopolymerizable photosensitive layer. Examples of the photosensitive lithographic printing plate include photosensitive lithographic printing plates having a photopolymerizable photosensitive layer as described in JP-A No. 2004-4145, JP-A No. 2005-84303 and the like.

  The photosensitive lithographic printing plate of the present invention is usually subjected to image exposure, and then an unexposed portion of the photosensitive layer is removed with a developer to obtain an image.

  In addition, as the plate making process of the photosensitive lithographic printing plate of the present invention, the entire surface may be heated before exposure, during exposure, and between exposure and development, if necessary. Such heating promotes an image forming reaction in the photosensitive layer, and may have advantages such as improvement in sensitivity and printing durability, and stabilization of sensitivity. Further, for the purpose of improving the image strength and printing durability, it is also effective to perform the entire post-heating or the entire exposure on the developed image. Usually, the heating before development is preferably performed under a mild condition of 150 ° C. or less. If the temperature is too high, problems such as covering up to the non-image area occur. Very strong conditions are used for heating after development. Usually, it is the range of 200-500 degreeC. If the temperature is low, sufficient image strengthening action cannot be obtained. If the temperature is too high, problems such as deterioration of the support and thermal decomposition of the image area occur.

  As a method for exposing a scanning exposure lithographic printing plate according to the present invention, a known method can be used without limitation. A desirable wavelength of the light source is 350 nm to 450 nm, and specifically, an InGaN semiconductor laser is suitable. The exposure mechanism may be any of an internal drum system, an external drum system, a flat bed system, etc. as shown in FIG. Among these exposure mechanisms, the internal drum system is particularly effective.

As a laser, Ar ion laser (364 nm, 351 nm, 10 mW to 1 W), Kr ion laser (356 nm, 351 nm, 10 mW to 1 W), He—Cd laser (441 nm, 325 nm, 1 mW to 100 mW), and solid laser, Nd: YAG (YVO ₄ ) and SHG crystal × 2 combinations (355 nm, 5 mW to 1 W), Cr: LiSAF and SHG crystal combination (430 nm, 10 mW), as a semiconductor laser system, KNbO ₃ ring resonator (430 nm, 30 mW), Combination of waveguide type wavelength conversion element and AlGaAs / InGaAs semiconductor (380 nm to 450 nm, 5 mW to 100 mW), combination of waveguide type wavelength conversion element and AlGaInP, AlGaAs semiconductor (300 nm to 350 nm, 5 mW to 100 m) W), AlGaInN (350 nm to 450 nm, 5 mW to 30 mW) and other pulse lasers include N ₂ laser (337 nm, pulse 0.1 to 10 mJ), and XeF (351 nm, pulse 10 to 250 mJ). In particular, an AlGaInN semiconductor laser (commercially available InGaN-based semiconductor laser 400 to 410 nm, 5 to 30 mW) is preferable in terms of wavelength characteristics and cost.

  In addition, a heating process is performed at a temperature of 50 ° C. to 150 ° C. for a period of 1 second to 5 minutes in order to increase the curing rate of the photopolymerization type photosensitive layer after image exposure with conventionally known actinic light and development. Thus, the curability of the non-image area can be improved and the printing durability can be further improved, which is more preferable.

  The above-mentioned photosensitive lithographic printing plate can be developed using a conventionally known developer to form an image. These conventionally known developers are described in JP-B-57-7427. Such a developing solution is mentioned.

  Further, the developed photosensitive lithographic printing plate is washed with water, a surfactant and the like as described in JP-A Nos. 54-8002, 55-1115045 and 59-58431. And a desensitizing solution containing gum arabic, starch derivatives and the like. These treatments can be used in various combinations for the post-treatment of the photosensitive lithographic printing plate of the present invention. The lithographic printing plate obtained by such processing is applied to an offset printing machine and used for printing a large number of sheets.

  Hereinafter, although the remarkable effect of the present invention is explained based on an example, the range of the present invention is not limited to these examples.

(Examples 1-3 and Comparative Examples 1-2)

(Evaluation of image unevenness on FM screen)
A high-sensitivity photosensitive lithographic printing plate PN-V for violet laser manufactured by Fuji Photo Film Co., Ltd. was prepared by the following method, and image unevenness on an FM screen was evaluated. Mounted on FUJIFILM Electronic Imaging Ltd Violet semiconductor laser setter Vx9600 (InGaN semiconductor laser 405nm ± 10nm emission / output 30mW), with exposure of 90μJ / cm ² and resolution of 2438dpi, Fuji Photo Film FM screen, TAFFETA 20 A 50% flat mesh was drawn.

The printing plate after exposure is sent to the above-described automatic developing device by changing the insertion angle, that is, the angle formed by the conveyance direction of the printing plate and the sub-scanning direction at the time of scanning exposure of the printing plate. After heating for 2 seconds, the PVA protective layer was removed by washing with water, followed by a development temperature of 28 ° C. and a development time of 20 seconds. The developing brush roller was equipped with two Molton brushes that were covered with a cylindrical sliding contact material made of polypropylene fiber knitted fabric and the end on the mounting side was tightened.
The developer was prepared by diluting a developer DV-2 manufactured by Fuji Photo Film Co., Ltd. five times with water. The plate after development was washed with a rinse bath, sent to a finisher treatment bath, and a solution obtained by diluting Fuji Photo Film Co., Ltd. gum solution FP-2W with water twice. The plate after the finisher was discharged after drying with hot air to obtain a planographic printing plate on which a 50% flat net of an FM screen was drawn. The flat net unevenness of the obtained lithographic printing plate was evaluated.

  As shown in Table 1, Example 1 was able to be stably processed without unevenness on the plate. In Examples 2 to 3, there was a slight level of unevenness on the plate, but there was no problem. However, in Comparative Examples 1 and 2, flat net unevenness on the plate was severely generated.

It is a figure which shows the structure of the pre-processing part of the automatic development apparatus of the planographic printing plate which concerns on this invention. It is a figure which shows the structure of the image development processing part of the automatic development apparatus of the planographic printing plate which concerns on this invention. It is a block diagram which shows one structural example of a rotation conveyance part, (a) is a top view, (b) is a side view. It is a figure which shows the highlight part of FM screen. It is a figure which shows FM screen halftone. (A) is a schematic block diagram showing the configuration of a single laser exposure apparatus with one laser device, and (b) is a schematic configuration diagram showing the configuration of a twin laser exposure apparatus with two laser devices. It is explanatory drawing which shows a mode that the printing plate was inserted with predetermined angle (theta) a- (theta) b with respect to the conveyance direction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Automatic developing device 10 Development processing part 12 Printing plate (photosensitive lithographic printing plate)
DESCRIPTION OF SYMBOLS 14 Developing part 16 Water washing part 18 Finishing process part 20 Drying part 24 Developing tank 200 Pre-processing part 300 Rotation conveyance part (printing plate rotation conveyance means)
Da Main scanning direction Db Sub scanning direction

Claims (3)

A processing method of a lithographic printing plate in which a photosensitive lithographic printing plate having a photopolymerizable photosensitive layer on a support is subjected to scanning exposure with a laser, and then conveyed to a development processing section and developed.
When transporting the photosensitive lithographic printing plate in the development processing section, a transport direction of the photosensitive lithographic printing plate and a sub-scanning direction orthogonal to a main scanning direction at the time of scanning exposure of the photosensitive lithographic printing plate; The method for processing a lithographic printing plate is characterized in that the angle is inclined in the range of 30 to 60 degrees.   2. The processing method of a lithographic printing plate according to claim 1, wherein when the photosensitive lithographic printing plate is inserted into the development processing section, the photosensitive lithographic printing plate is inserted while being inclined within the range. A photolithographic printing plate having a photopolymerizable photosensitive layer on a support is scanned and exposed by a laser, and is then conveyed to a development processing unit for development and an automatic development apparatus for a lithographic printing plate,
In the middle of the transport path for transporting the photosensitive lithographic printing plate to the development processing unit, the transport direction of the photosensitive lithographic printing plate and the sub-scanning direction orthogonal to the main scanning direction at the time of the scanning exposure of the photosensitive lithographic printing plate. An automatic developing device for a lithographic printing plate, comprising printing plate rotation conveying means for tilting the scanning direction within a range of 30 to 60 degrees.

Images