JP4500625B2 - Planographic printing plate processing method and processing apparatus - Google Patents

Description

  The present invention relates to a lithographic printing plate processing method and a lithographic printing plate processing apparatus in which a lithographic printing plate having a photosensitive layer or a heat-sensitive layer is subjected to laser exposure and then developed in a step having development, and a heater for heating a developer. The present invention relates to a lithographic printing plate processing method and a lithographic printing plate processing apparatus.

  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.

  In order to form a lithographic printing plate, development is performed after recording on the printing plate by laser exposure. Generally, automatic development apparatuses such as Patent Document 1 and Patent Document 2 described below are used for developing a printing plate. As an automatic developing device, a device including a process including development, washing with water and finishing is widely used.

  Further, the developing unit is generally maintained at a constant temperature by using a heater for heating the developer and a cooling pipe for cooling the developer.

JP-A-5-53284 JP-A-9-160202

  When a printing plate on which an image was recorded by laser exposure was developed, precipitates were generated on the surface of the heating heater for the developer when the number of processed printing plates increased, and deposited on the heater surface when the number of processed plates increased further. In some cases, the deposits fall off, causing image defects floating in the developer or adhering to the lithographic printing plate during the development process.

The present invention has been made based on the background as described above. The purpose of the lithographic printing plate processing method and lithographic printing plate processing apparatus is that, even if the photosensitive lithographic printing plate is processed for a long period of time, there is no deposit in the developing portion and the cleaning and maintenance properties after the processing are excellent. Is to provide.
Another object of the present invention is to provide a lithographic printing plate processing method and a lithographic printing plate processing apparatus capable of developing a photosensitive lithographic printing plate without causing image defects such as fouling even if the photosensitive lithographic printing plate is processed for a long period of time.

  As a result of intensive studies, the present inventors have found the following. A lithographic printing plate on which an image is formed by laser exposure is less likely to cause a difference in developing solution dissolution between an image portion and a non-image portion dissolved in the developing solution, compared to a lithographic printing plate in which a conventional lithographic film is closely baked. For this reason, substances that are difficult to dissolve and disperse in the developer are contained in a larger amount than lithographic printing plates that have been used to adhere and burn a lithographic film. In a lithographic printing plate that forms an image by laser exposure, when the number of processed plates increases, precipitates are generated on the surface of the heater for heating the developer, and when the number of processed plates increases further, the precipitates deposited on the heater surface fall off. Then, it has been found that image defects may occur in the developing solution, which may float or adhere to the lithographic printing plate being developed.

And, as a result of further intensive studies, the inventor used a heater with a heater watt density of 5 W / cm ² or less for heating the developing part of the automatic developing device, and no precipitate was generated on the heater surface. It has been found that even if the number of processed sheets is increased, there is no deposit adhering to the lithographic printing plate, and stable processing without image defects can be performed over a long period.

That is, the present invention is a processing method of a lithographic printing plate in which a lithographic printing plate having a photosensitive layer or a heat-sensitive layer is subjected to laser exposure and then processed in a step having development, and the heater watt density is controlled to 5 W / cm ² or less. The developer is heated by a heated heater.

The heater watt density is 5 W / cm ² or less, 0.1 W / cm ² or more, more preferably 4 W / cm ² or less, and 0.3 W / cm ² or more. If the heater watt density is greater than 5 W / cm ² , precipitates are likely to be generated on the heater surface.

  Further, if the heater watt density is small, it is necessary to increase the heater surface area in order to increase the power capacity (W), and it is impossible to mount the heater in a limited space.

  If the heater watt density is small, the reason why there are few precipitates on the heater surface is considered to be because the heater surface temperature in the developer is low.

  Any heater can be used, but a cartridge heater using a nichrome wire as a heating element can be suitably used from the viewpoint of cost and mountability.

  The heater surface material is preferably stainless steel such as SUS316, but may be coated with Teflon or the like.

  The heater can be installed in a development processing tank, a developer circulation pipe, and the like.

  In addition, a control device for controlling the operation of the heater and a safety device for preventing emptying are provided.

  Furthermore, by attaching a cooling pipe connected to a cooler to the developing unit and controlling heating and cooling, the developing temperature can be accurately maintained.

The present invention relates to a lithographic printing plate processing method and a lithographic printing plate processing apparatus in which a lithographic printing plate having a photosensitive layer or a thermosensitive layer is subjected to laser exposure and then processed in a step having development, and the heater watt density is 5 W / By heating the developer with a heater controlled to be cm ² or less, there is no generation of precipitates on the heater surface, and there is an excellent effect that there is no debris adhesion over a long period of development processing.

As the automatic developing apparatus used in the present invention, any apparatus can be used as long as it has a developing process. Hereinafter, an embodiment of an automatic developing apparatus of the present invention will be described with reference to the drawings.
FIG. 1 shows an embodiment of an automatic developing apparatus which is a processing apparatus for a planographic printing plate according to the present invention. The automatic developing device 10 is applied to a processing method for developing a photosensitive or heat-sensitive lithographic printing plate that has been image-exposed by an exposure device (not shown).

  In the automatic developing device 10, the washing brush of the washing unit may or may not be attached. There may also be a pre-water washing part in front of the water washing part.

  The automatic developing apparatus 10 includes a developing unit 14 for processing a planographic printing plate (hereinafter also referred to as a printing plate) 12 with a developer, and a plate surface while supplying washing water to the printing plate 12 processed with the developer. 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 10, a developing process, a washing process, a finishing process, and a drying process are sequentially arranged along the conveyance direction (arrow A in FIG. 1) of the printing plate 12.

  A processing tank 22 is provided in the automatic developing apparatus 10. In this processing tank 22, a developing tank 24 is formed at a position that becomes the developing section 14 as a processing tank, and a washing tank 26 and a finishing processing tank 28 are formed at positions that become the washing section 16 and the desensitizing processing section 18. Yes. 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-shaped insertion port 32 is formed on the insertion side of the printing plate 12 to the automatic developing device 10 (left side in FIG. 1). An insertion portion 34 is formed on the insertion port 32 side of the developing portion 14.

  The automatic developing apparatus 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 for inserting the printing plate 12 for performing processing in the automatic developing apparatus 10 excluding processing in the developing unit 14.

  A rubber conveyance roller pair 42 is disposed in the insertion portion 34 adjacent to the insertion port 32. 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 transport roller pair 42 is driven to rotate, and feeds the printing plate 12 from the insertion port 32 to the developing unit 14 at an angle in the range of about 10 ° to 31 ° with respect to the horizontal direction. In the automatic developing apparatus 10 used for processing the single-sided type printing plate 12, the photosensitive layer (photosensitive surface) or the heat-sensitive layer (heat-sensitive surface) is inserted from the insertion port 32 in a state in which the photosensitive layer (photosensitive surface) is directed upward. That is, the printing plate 12 is processed by the automatic developing device 10 with the photosensitive surface or the heat-sensitive surface directed upward. In the automatic developing apparatus 10 according to the present invention, the photosensitive layer (photosensitive surface) or the heat-sensitive layer (heat-sensitive surface) is inserted downward from the insertion port 32, and the printing plate 12 has the photosensitive surface or the heat-sensitive surface. The development processing may be performed in a state of being directed downward.

  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.

  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. Further, in the developing tank 24, a transport roller pair 50 is disposed at the center of the transport path of the printing plate 12, and transport roller pairs 52a and 52b are disposed on the water washing section 16 side which is a downstream portion.

  The developing tank 24 includes a guide plate, a transport roller, and the like corresponding to the type of the printing plate 12 to be processed between the transport roller 48 and the transport roller pair 50 and between the transport roller pair 50 and the transport roller pairs 52a and 52b. A substantially U-shaped transport for transporting the printing plate 12 while being immersed in the developer in the developing tank 24 by providing a brush roller used as a rubbing member and a backup roller or guide plate. A path is formed. The configuration of the conveyance path in the developing tank 24 will be described later.

  On the other hand, in the developing tank 24, a brush roller 142 and a transport roller 60 are disposed between the transport roller pair 50, 52a, 52b. The brush roller 142 is used as an example of a rubbing member, and the brush roller 142 and the conveyance roller 60 are attached so as to face the upper surface side of the printing plate 12 conveyed between the conveyance roller pair 50, 52a, 52b. It has been. The brush roller 142 contacts the upper surface of the printing plate 12 while rotating in a predetermined direction and a predetermined rotation direction, thereby brushing the photosensitive layer or the heat-sensitive layer on the upper surface side of the printing plate 12 and removing unnecessary photosensitive light with a developer. The removal of the layer or the heat-sensitive layer is facilitated.

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

  Further, the pair of conveying rollers 52a and 52b are formed, for example, by rubber rollers on the outer periphery, and are fed into the washing unit 16 while sandwiching the printing plate 12 and pulling it out from the developing tank 24.

  In the developing tank 24, spray pipes 54 and 56 are provided between the transport roller 48 and the transport roller pair 50 and in the vicinity of the bottom surface between the transport roller pair 50 and the transport roller pairs 52a and 52b. The developer in the developing tank 24 sucked by a pump (not shown) is supplied to the spray pipes 54 and 56, and the developer is ejected from the spray pipes 54 and 56. Thereby, the developing solution in the developing tank 24 is agitated so that the printing plate 12 can be uniformly processed. At this time, the developer is ejected from the spray pipe 54 along the width direction that is orthogonal to the transport direction of the printing plate 12, so that the developer ejected from the spray pipe 54 is transported in the developer tank 24. It goes around the front and back surfaces of the printing plate 12 to prevent rapid development processing and uneven processing of the printing plate 12.

  Further, the developing unit 14 is provided with a heater 101 for heating the developer. The heater 101 is installed so as not to be in direct contact with the bottom of the processing tank 22. In the vicinity of the heater 101, a temperature control detector and a safety device are incorporated.

FIG. 2 is a diagram illustrating the heater 101 of the present embodiment. As shown in FIG. 2, the heater 101 is a long member having a circular cross section, and includes a first extension 101 a that extends in a direction perpendicular to the conveyance direction of the printing plate 12 (not shown), and the first extension. A folded portion 101b that extends substantially vertically from 101a and is parallel to the printing plate 12 being conveyed, and a second extended portion 101c that is connected to the folded portion 101b and extends substantially parallel to the first extended portion 101a. And have. Thus, the heater 101 is configured so that the effective heat generation length is as long as possible. In this embodiment, the cross-sectional diameter D of the heater 101 is 3 mm to 30 mm, and the effective heat generation length is 10 cm to 550 cm. The power capacity of the heater 101 was changed from 500W to 10000W. At this time, since the heater watt density of the heater 101 can be obtained by the power capacity with respect to the surface area of the heat generating portion, it can be set to 0.1 W / cm ² to 5 W / cm ² .

  Further, a fixed amount of replenisher is supplied to the developing unit 14 by a replenishment pump (not shown). The replenishment can be performed by measuring the plate length of the printing plate 12 with a sensor in the insertion portion, calculating the area from the pre-input plate width, and replenishing. Furthermore, you may replenish at a fixed time interval. Furthermore, a conductivity sensor (not shown) may be incorporated in the developing tank and supplemented from the change.

  The printing plate 12 drawn from the developing tank 24 by the conveying roller pair 52a, 52b is sent to the washing unit 16 while the developer attached to the surface is squeezed down by the conveying roller pair 52a, 52b.

  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 transport rollers 62 and 64, with a pair of transport paths 12 in the vertical direction. 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 spray direction of flushing water from the spray pipes 66 and 68 is such that the spray pipe 66 is upstream in the transport direction of the printing plate 12 and the spray pipe 68 is downstream in the transport direction of the printing plate 12. It may be in another direction. Further, the replenishment of the washing water is supplied to the washing tank 26 by means not shown in accordance with the processing amount of the printing plate 12.

  Furthermore, a preservative may be automatically added 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 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, and the gum solution adheres to the peripheral surfaces of the rollers and damages the printing plate 12. Try 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 automatic developing device 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 desensitizing 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.

  On the other hand, the developing unit 14 is provided with a shielding lid 100 such that the lower surface is below the level of the developer stored in the developer tank 24, and the level of the developer in the developer tank 24 is in contact with air. The area is narrowed. Further, the auxiliary insertion port (reentry insertion port) 40 of the cover 36 is blocked by a shielding member (not shown), and this shielding member prevents outside air from entering the developing unit 14.

  When a brush roller is newly disposed in the shielding lid 100 together with a recess 100A that protrudes from the developer surface and a roller 100A into which the transport roller 60 enters, and a roller above the transport roller pair 50, the brush is provided. A recess 100B into which the roller enters is formed.

  In the automatic developing apparatus 10, by disposing the liquid level lid 100 in the developing tank 24, deterioration due to the developer in the developing tank 24 coming into contact with carbon dioxide in the air or the like is prevented. I am doing so. 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 52a, 52b. May be prevented from coming into contact with fresh outside air or evaporation of moisture in the developer.

  In the developing tank 24 of the automatic developing device 10, a conveyance roller 48 </ b> A is disposed below the conveyance roller 48 so as to face the conveyance roller 48. As a result, the printing plate 12 is inserted between the transport rollers 48 and 48 </ b> A by the transport roller pair 42 of the insertion portion 34. The conveyance roller 48 </ b> A rotates following the rotation of the conveyance roller 48, sandwiches the printing plate 12 inserted between the conveyance roller 48 and draws it into the developing tank 24.

  In the developing tank 24, a guide plate 44 is disposed between the transport roller 48 and the transport roller pair 50. The guide plate 44 guides the printing plate 12 drawn by the transport rollers 48 and 48A so as to be inserted between the transport roller pair 50 at a predetermined angle.

  A guide plate 46 is disposed on the conveyance roller pair 50 and the conveyance roller pairs 52a and 52b. The guide plate 46 guides the printing plate 12 sent out by the conveying roller pair 50 toward the conveying roller pairs 52 a and 52 b along the bottom surface of the developing tank 24.

  The guide plate 46 is opposed to the brush roller 142 and the transport roller 60. The brush roller 142 sandwiches the printing plate 12 conveyed on the upper surface of the guide plate 46 with the guide plate 46 with a predetermined brush pressure. In this state, the brush roller 142 is rotationally driven in a predetermined direction, whereby the surface of the printing plate 12 is brushed and immersed in the developer to facilitate the removal of the photosensitive layer. The transport roller 60 prevents the printing plate 12 being transported on the guide plate 46 while being brushed by the brush roller 142 from being lifted from the guide plate 46, so that the printing plate 12 is moved on the guide plate 46. It is surely guided toward the transport roller pair 52a, 52b.

  The lithographic printing plate 12 having photosensitivity or heat sensitivity which can be applied to the present invention is not particularly limited, and various lithographic printings in which an image recording layer such as a photosensitive layer and a heat sensitive layer is provided on a support. Name the original edition. Examples of the image recording layer include thermal positive types described in JP-A-7-285275 and Japanese Patent Application No. 2002-154279, JP-A-7-20625, and JP-A-11-218903. And the thermal poly negative type described in JP-A Nos. 2001-100412 and 2002-169282.

  Particularly preferred are the multilayer thermal positive types described in JP-A-11-218914, Japanese Patent Application No. 2002-499707, Japanese Patent Application No. 2003-189095, and Japanese Patent Application No. 2003-181121. The thermal positive type of the multilayer may have a multilayer structure of at least two layers.

In the present invention, when the lithographic printing plate 12 is developed, the developer is heated by the heater 101 whose heater watt density is controlled to 5 W / cm ² or less.
A procedure for controlling the heater watt density during development will be described with reference to FIG.
As shown in FIG. 3, at the time of development, the heater 101 is activated to adjust its power capacity (step S101). Then, the heater watt density is measured based on the power capacity of the heater in the developing unit 14 measured by the detection unit (not shown) (step S102).

Next, it is determined whether the measured heater watt density is 5 W / cm ² or less (step S103). If the heater watt density is 5 W / cm ² or less, it is determined that the heater watt density is normal. Move to the step to confirm the end. If the heater watt density is greater than 5 W / cm ² , the process returns to the step of adjusting the power capacity in step S101, and the power capacity of the heater is lowered. Then, the heater watt density is measured again (step S102), and it is determined whether or not the measured heater watt density is 5 W / cm ² or less (step S103). Thus, the adjustment of the power capacity is repeated until the heater watt density becomes 5 W / cm ² or less.

When the heater watt density is 5 W / cm ² or less, after determining that the heater is normal, it is determined whether or not the processing time has ended (step S104). Then, the driving of the heater 101 is stopped. On the other hand, if the processing time has not ended, the process returns to the step of measuring the heater watt density in step S102, and the heater watt density is controlled to be 5 W / cm ² or less during development.

  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.

(Evaluation of presence or absence of heater deposits and adhesion of debris on the printing plate during long-term treatment)
A lithographic printing plate precursor HP-S (a thermal positive multi-layer printing material manufactured by Fuji Photo Film Co., Ltd.) is used with a Trend setter VX manufactured by Creo, a beam intensity of 8 W, a drum rotation speed of 150 rpm, an FM screen Staccato 20 and an AM screen of 175 lpi, 50 After drawing the% flat mesh, the automatic developer 10 described in detail in FIG. 1 is used to apply the initial charge developer DT-2 (developer for thermal positive manufactured by Fuji Photo Film Co., Ltd.) 1: 8 with water. Dilute and feed. The replenisher DT-2R (Fuji Photo Film Co., Ltd., thermal positive replenishment developer) was replenished with conductivity while being diluted 1: 6.5 with water. Development processing was carried out with the developer temperature kept at 30 ° C. and a development time of 12 seconds. Water was added to the washing section, and 80 ml was replenished per 1 m ^{2 of} the printing plate. The finishing section was loaded with finisher FG-1 (diluted 1: 1) manufactured by Fuji Photo Film Co., Ltd. Replenishment was performed with 20 ml of FG-1 (diluted 1: 1) per 1 m ² of printing plate.

  The treatment was carried out by printing 60 sheets of 1030 × 800 mm per day for 3 months, and the presence or absence of deposits on the heater and the degree of deposit on the printing plate were examined. The difference in heater watt density and performance are shown in Table 1.

  In Examples 1 and 2, there was no precipitate on the heater surface, and no debris adhered to the printing plate, and the treatment could be performed stably for 3 months. In Comparative Example 1, a large amount of deposits of the heat-sensitive layer component of the lithographic printing plate was generated on the heater surface, and debris was deposited on the plate from the second month of treatment.

Developing unit heater of the first embodiment, power capacity 1600 W, the effective heating length 2900 mm, were placed one of the heater watt density 2.2 W / cm ² at the heat-generating unit surface area 728cm ² in the heater pipe diameter 8 mm. The surface material of the heater was SUS316.

Developing unit heater of the second embodiment, the power capacity 1300 W, the effective heating length 1650 mm, it was placed one of the heater watt density 3.1 W / cm ² at the heat-generating unit surface area 414Cm ² a heater pipe diameter 8 mm. The surface material of the heater was SUS316.

The developing unit heater of Comparative Example 1 was installed with a power capacity of 1236 W, an effective heat generation length of 223 mm, a heater pipe diameter of 18 mm, a heat generating surface area of 126 cm ² and a heater watt density of 9.8 W / cm ² . The surface material of the heater was SUS316.

1 is a diagram showing an embodiment of an automatic developing device which is a processing device for a lithographic printing plate according to the present invention. It is a figure explaining the heater of the processing apparatus of a lithographic printing plate. It is a flowchart explaining the procedure which controls a heater watt density at the time of image development.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Automatic developing device 12 Planographic printing plate 14 Developing part 16 Washing part 18 Desensitizing part 20 Drying part 24 Developing tank 101 Heater 142 Brush roller 52a, 52b Developing squeeze roller

Claims (5)

A method for processing a lithographic printing plate, in which a thermal positive type lithographic printing plate having a photosensitive layer or a heat-sensitive layer having a multilayer structure of two or more layers is exposed to laser and then developed while being immersed in a developer in a developing tank,
Wherein when the lithographic printing plate development, the power capacity of the heater of the developing unit is measured, the heater watt density measured based on the power capacity of the heater watt density of the heater is greater than 5W / cm ² 5W / A method for processing a lithographic printing plate, wherein the processing is controlled to be cm ² or less. A processing device for a lithographic printing plate that develops a lithographic printing plate of a thermal positive type in which a photosensitive layer or a heat-sensitive layer has a multilayer structure of two or more layers while being immersed in a developer in a developing tank,
A developing unit for developing the lithographic printing plate;
A heater provided in the developing unit and a detection unit for measuring the power capacity of the heater;
The lithographic printing plate processing apparatus, wherein the heater has a heater watt density measured based on the power capacity, controlled to 5 W / cm ² or less. A lithographic printing plate processing apparatus according to claim 2,
A first extension portion in which the heater extends in a direction perpendicular to a transport direction of the planographic printing plate, and a folding portion that extends substantially perpendicularly from the first extension portion and is parallel to the transported planographic printing plate And a processing device for a lithographic printing plate, which is connected to the folding portion and has a second extension portion substantially parallel to the first extension portion. A lithographic printing plate processing apparatus according to claim 2 or 3,
An apparatus for processing a lithographic printing plate, wherein the heater is a long member having a circular cross section, the heater having a cross sectional diameter of 3 mm to 30 mm, and an effective heat generation length of 10 cm to 550 cm. A lithographic printing plate processing apparatus according to any one of claims 2 to 4, comprising:
A processing device for a lithographic printing plate, wherein the heater has a power capacity of 500 W to 10,000 W.

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