JP2006091419A - Liquid heating method and device therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid heating method that generates no image defect and reduces cleaning and maintenance after processing even when lithographic printing forms to be developed where images are recorded by a material exposing means increase in number. <P>SOLUTION: Liquid in which solid matter is dissolved or dispersed and which possibly has the solid matter deposited above designated high temperature is put in a container having a discharge port and a suction port, and heated by a heater while circulated through the discharge opening and suction opening. This liquid heating method is characterized in that the heater heating the liquid while dipped in the liquid is covered with a guide cover and the liquid is sucked from a portion of the guide cover to form a liquid current in the gap formed between the guide cover and the surface of the heater. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a heating method and a heating apparatus for heating a processing solution of a photosensitive material. In particular, the present invention relates to a lithographic printing plate processing method for developing a lithographic printing plate having a photosensitive layer or a heat-sensitive layer after laser exposure, and a developer heating method and apparatus in a lithographic printing plate processing apparatus.

  In general, a photosensitive lithographic printing plate is developed by a photosensitive lithographic processing apparatus (hereinafter referred to as a printing plate processor). In this printing plate processor, the development process is carried out by immersing the photosensitive lithographic printing plate on which the image is recorded in the developing tank while transporting the photosensitive lithographic printing plate in the developing tank, such as a rotating brush roller provided in the developing liquid. The rubbing means is used to remove the photosensitive layer corresponding to the non-image forming area of the photosensitive lithographic printing plate. In this printing plate processor, a photosensitive lithographic printing plate that has been processed with a developer is washed with washing water in a washing section (washing treatment) and then insensitive by applying a gum solution in a desensitizing section. An oiling treatment is performed. Here, the water washing section is composed of an inlet / outlet roller and a spray pipe, and the washing of the planographic printing plate is performed by discharging washing water from the spray pipe onto the planographic printing plate after passing through the inlet roller. Up to now, conventional negative and positive printing plates have been mainly used as photosensitive lithographic printing plates, but with recent CTP conversion, systems using photopolymer plates and thermal plates are frequently used. It is like that.

  In the development process in the lithographic printing plate process, it is essential to keep the developer temperature constant. The processability of the developer varies greatly depending on the temperature. Accordingly, it is essential to stabilize the developer temperature in order to provide a stable development process. Normally, a heater is provided in the development process, and the developer is heated to keep the temperature of the developer constant and perform stable processing. In addition, a cooling pipe is provided as appropriate to perform processing at a more stable developer temperature.

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

FIG. 3 is an enlarged perspective view showing the vicinity of the heater portion of the conventional apparatus.
In the figure, 22 is a processing tank, 22a is a liquid suction port provided at the bottom of the processing tank, 54 and 56 are spray tubes, and 200 is a heater for heating the developer.
The spray tubes 54 and 56 extend from the wall surface of the processing tank 22 in a direction perpendicular to the conveying direction of the printing plate. The heater 200 is disposed below the spray pipes 54 and 56 and on a substantially vertical bisector of both the spray pipes 54 and 56.

  The spray tube 54 has a hole for ejecting the developer in the direction W1 perpendicular to the transport direction of the printing plate. On the other hand, the spray pipe 56 has a large number of holes for ejecting the developer on the downstream side W2 in the transport direction of the printing plate. The intervals and directions of the holes are determined so that the liquid flows discharged from these many holes are parallel to each other. Then, the liquid discharged from the spray tube 54 and the spray tube 56 is sucked into the liquid suction port 22a.

  However, when the planographic printing plate is processed, the photosensitive layer on the planographic printing plate is eluted in the developer. The photosensitive layer contains dyes or pigments, and these dyes or pigment components are contained in the developing solution in accordance with the development process. As described above, since the developer temperature is kept constant by at least heating means such as a heater, the developer containing the photosensitive layer component (development fatigue solution) is heated by the heater as the development process proceeds. Will be.

  Now, when the lithographic printing plate on which the image is recorded by the exposure means is developed, a precipitate is generated on the surface of the heater for heating the developer when the number of processed printing plates increases, and further the precipitate deposited on the heater surface. Fall off, and there is a problem that an image defect floating in the developing solution or adhering to the lithographic printing plate being developed is generated.

  4A and 4B are perspective views showing the situation near the surface of the heater for heating when the number of processed printing plates is increased. FIG. 4A is an apparatus according to the present invention (described later), and FIG. Each case is shown. In FIG. 4B, 200 is a heater for heating the developer, 22 is a processing tank, and 22a is a liquid suction port provided at the bottom of the processing tank. As can be seen from the figure, while the lithographic printing plate is immersed in the developer in the processing tank 22 and processed, the photosensitive layer on the lithographic printing plate elutes into the developer, and therefore the dye or dye in the photosensitive layer As the pigment component was contained and the number of processed printing plates increased, precipitates were deposited on the surface of the heater. As this progressed, the precipitate deposited on the surface of the heater eventually dropped out of the heater and deposited at the bottom of the apparatus. Due to the stirring of the developing solution, the sediment floats in the developing solution or adheres to the lithographic printing plate during the developing process, resulting in a problem that image defects occur.

  The present applicant has noticed the phenomenon that precipitates are concentrated on the surface of the heater in this way, and further investigated why the precipitates are concentrated on the surface of the heater. As a result, it was found that the developer was locally heated near the heater surface, and that the dye and pigment contained in the developer were deposited on the heater by changing the stable dispersion state at high temperatures. .

  The dye and pigment components thus deposited cause image defects, and deposits adhere to the developing section heater, which places a burden on cleaning and maintenance after the processing is completed.

  The present invention has been made to solve the above-described drawbacks. Even when the photosensitive lithographic printing plate is processed for a long period of time, there is no deposit in the developing unit heater, and no image defect due to the deposit occurs. An object of the present invention is to provide a liquid heating method and apparatus excellent in cleaning and maintainability after completion of the treatment.

  In order to achieve the above object, the invention according to claim 1 relates to a liquid heating method, wherein a liquid in which a solid content is dissolved or dispersed is placed in a container having a discharge port and a liquid suction port, and the discharge port and In a liquid heating method in which heating is performed with a heater while circulating through the liquid suction port, a heater that is heated while being immersed in the liquid is covered with a guide cover, and liquid is absorbed from a part of the guide cover. A liquid flow is formed in a gap formed between the guide cover and the surface of the heater.

  According to a second aspect of the present invention, in the liquid heating method according to the first aspect, the liquid is a processing liquid used when processing a photosensitive material.

  According to a third aspect of the present invention, in the liquid heating method according to the first or second aspect, the heater is rod-shaped, the rod-shaped heater is covered with a cylindrical guide cover, and the liquid is applied from one side of the cylindrical guide cover. The liquid circulation is performed by absorbing the liquid.

  The invention according to claim 4 relates to a liquid heating device, wherein a liquid in which a solid content is dissolved or dispersed is placed in a container having a discharge port and a liquid suction port, and is circulated through the discharge port and the liquid suction port. In the liquid heating apparatus heated by the heater, the guide cover that covers the heater that is heated while being immersed in the liquid, and the surface of the guide cover and the heater by absorbing liquid from a part of the guide cover And a liquid absorbing means for forming a liquid flow in a gap formed therebetween.

  According to a fifth aspect of the present invention, in the liquid heating apparatus according to the fourth aspect, the liquid is a processing liquid used when processing a photosensitive material.

  According to a sixth aspect of the present invention, in the liquid heating apparatus according to the fourth or fifth aspect, the heater is a rod-shaped heater, the rod-shaped heater is covered with a cylindrical guide cover, and from one side of the cylindrical guide cover The liquid circulation is performed by sucking the liquid.

  The invention according to claim 7 is the liquid heating apparatus according to any one of claims 4 to 6, wherein the cylindrical guide cover is detachably provided.

According to the above configuration, when an image is recorded on a lithographic printing plate coated with a photosensitive material for image formation by a material exposure means and developed, the developer is heated even if the number of processed printing plates increases. Precipitates are not generated on the heater surface, and therefore precipitates deposited on the heater surface do not fall off, so that the fallen precipitates such as dyes and pigments float in the developer or are being developed. There was no adhesion to the printing plate, and the problem of image defects due to this was solved.
Further, since deposits do not adhere to the developing section heater, cleaning and maintenance after the processing is reduced.

Hereinafter, the best mode for carrying out the invention will be described in detail.
The present invention is a development processing method and apparatus for a lithographic printing plate coated with a photosensitive material. An example of an embodiment of the present invention is shown in FIG.
A printing plate processor 10 shown in FIG. 1 performs development processing of a photosensitive lithographic printing plate that has been exposed by an exposure device (not shown). Here, the exposure apparatus differs depending on the system. In the case of a CTP plate making system, image data is directly converted into a photosensitive lithographic printing plate without using a medium by using a solid laser, a semiconductor laser, a gas laser, a CO ₂ laser, or the like. Exposure. Prior to exposure, RIP processing is performed to form an image pattern necessary for exposure.

  The printing plate processor 10 generally has a developing unit for processing a photosensitive lithographic printing plate with a developer, a washing unit for washing with water, and a finisher for applying a gum solution to the lithographic printing plate after washing to desensitize the plate. A drying section is provided for drying the lithographic printing plate coming out from the section and the finisher section. The present invention is not limited to the above general structure, and can be applied as long as it has at least a development processing mechanism.

  The printing plate processor 10 includes a developing unit 14 for processing the printing plate 12 with a developing solution, a rinsing unit 16 for brushing and rinsing the plate surface while supplying rinsing water to the printing plate 12 processed with the developing solution, A finishing processing unit 18 for applying a gum solution for protecting the plate surface to the subsequent printing plate 12 to desensitize it and a drying unit 20 for drying the printing plate 12 are provided. That is, in the printing plate processor, a developing process, a washing process, a finishing process, and a drying process are sequentially arranged along the direction of conveyance of the printing plate 12 (arrow A in FIG. 1).

  A processing tank 22 is provided in the printing plate processor 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-like insertion port 32 is formed on the insertion side of the printing plate 12 to the printing plate processor (left side in FIG. 1). An insertion portion 34 is formed on the insertion port 32 side of the portion 14.

The printing plate processor 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 printing plate processor 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 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. In the printing plate processor used for processing the single-sided type printing plate 12 (12, 12C), the photosensitive layer (photosensitive surface) is inserted from the insertion port 32 in a state of being directed upward. That is, the printing plate 12 is processed by the printing plate processor 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.

  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.

  Further, the developing tank 24 transports a guide plate, a transport roller, etc. according 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 pair 52. By providing parts, a brush roller used as a rubbing member, a backup roller or a guide plate, a substantially U-shaped transport path for transporting the printing plate 12 while being immersed in the developer in the developing tank 24 is provided. It 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, the brush roller 142 and the transport roller 60 are disposed between the transport roller pair 50 and 52. 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 and 52. Yes. 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 on the upper surface side of the printing plate 12 and removing an unnecessary photosensitive layer with a developer. Has come to promote.

  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. Then, it is guided obliquely upward toward the conveying roller pair 52. At this time, the upper surface side of the printing plate 12 is brushed by the brush roller 142.

  Further, the conveying roller pair 52 is formed, for example, by a rubber roller at the outer periphery, and is 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 conveyance roller 48 and the conveyance roller pair 50 and near the bottom surface between the conveyance roller pair 50 and the conveyance roller pair 52. A heater 200 attached to the side surface of the developing tank is provided below the pair of conveyance rollers 50. The heater has a cylindrical shape, and a circulation guide cover 202 is provided concentrically with the heater on the side surface of the heater. The developing solution in the developing tank 24 sucked by a pump (not shown) is supplied to the spray pipes 54 and 56, and the developing solution 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.

  By the way, the guide cover 202 provided to cover the heater side surface according to the present invention is installed so as to cover from the heater tip portion to the heater root portion, and as shown in FIG. The liquid is sucked.

2 is an enlarged perspective view showing the spray tubes 54 and 56 and the heater 200 in FIG. 1. FIG. 2A shows a state in which the guide cover 202 for covering the heater side surface is removed from the heater 200, and FIG. The state which installed the cover 202 in the form which covers from the front-end | tip part of the heater 200 to a heater root part is each shown.
In the figure, 22 is a processing tank, 22a is a liquid suction port provided at the bottom of the processing tank, 54 and 56 are spray pipes, 200 is a heater for heating a developing solution, and 202 is a guide cover for circulation.

The spray tubes 54 and 56 extend from the wall surface of the processing tank 22 in a direction perpendicular to the conveying direction of the printing plate. The heater 200 is disposed below the spray pipes 54 and 56 and on a substantially vertical bisector of both the spray pipes 54 and 56.
The spray tube 54 has a hole for ejecting the developer in the direction W1 perpendicular to the transport direction of the printing plate. On the other hand, the spray pipe 56 has a large number of holes for ejecting the developer on the downstream side W2 in the transport direction of the printing plate. The intervals and directions of the holes are determined so that the liquid flows discharged from these many holes are parallel to each other.

  The circulation guide cover 202 is an L-shaped hollow pipe whose hollow inner diameter is such that the liquid flow W3 is still between the hollow inner side and the side surface of the heater 200 even when the heater 200 is concentrically housed therein. The size is such that is formed. One end 202 a of the L-shaped hollow pipe is inserted into the heater 200 from the front end to the vicinity of the base, and the other end 202 b is fitted into a liquid suction port 22 a provided at the bottom of the processing tank 22.

  FIG. 2B illustrates a state in which one end 202a of the L-shaped hollow pipe is fitted to the heater 200 and the other end 202b is fitted to the liquid suction port 22a. By sucking the liquid from the liquid suction port 22a in such a state, a liquid flow W3 is formed from the heater 200 through the circulation guide cover 202 toward the liquid suction port 22a. As described above, the liquid temperature W3 from the heater 200 toward the circulation guide cover 202 can warm the developer without causing the surface temperature of the heater 200 to rise extremely.

  The length of the guide cover 202 is not particularly limited as long as the effect can be exhibited, but the shape is determined by a relative relationship with the heater length. In other words, if only the tip of the heater is covered and most of the heater is exposed, the liquid flow spreads at the heater root where the heater is exposed, and the heater surface temperature is not sufficiently suppressed. It becomes. Therefore, the location where there is no guide cover on the heater is within 20 cm, more preferably within 10 cm. The distance between the heater 200 and the guide cover 202 should be within 15 mm, preferably within 10 mm so as not to impair the flow rate of the developer flowing between the heater 200 and the guide cover 202. In order to increase the interval, it is necessary to appropriately select a circulation motor having a power suitable for the interval and increase the circulation amount. Further, if the guide cover 202 can be easily attached and detached in the developing tank, the internal maintenance can be easily performed periodically.

A liquid flow is formed by mounting a guide cover on the heater and sucking the liquid. By this liquid flow, the heater surface temperature can warm the developer without extremely increasing the temperature.
Here, one liquid absorbing means is provided, but a plurality of liquid absorbing means may be provided. Moreover, although the cylindrical thing was used as a shape of a heater, the shape of a heater is not limited to this.
Further, a waste liquid port (not shown) is provided at the bottom of the developing tank, and the developer can be discharged when the liquid is exchanged.

  As described above, the surface temperature of the heater 200 can be heated by the liquid flow W <b> 3 flowing so as to wrap the entire heater 200 without excessively increasing the temperature.

As a result of processing the printing plate using the apparatus shown in FIG. 2, even if the number of processed plates increased, the heater surface always did not precipitate at all as shown in FIG. 4 (a). . This is because the photosensitive layer on the lithographic printing plate elutes into the developer while the lithographic printing plate is immersed in the developer in the processing tank 22 and the dye or pigment component in the photosensitive layer is contained. Even so, the liquid flow generated by the apparatus according to the present invention is for cooling so that the surface of the heater does not always exceed the desired temperature.
Since no precipitate was deposited on the surface of the heater, no image defect problem occurred as a result. In addition, since no deposits are attached to the heater, cleaning and maintenance after the processing is completed easily.

Returning to FIG. 1 again, the subsequent processing will be described.
A fixed amount of replenisher is replenished to the developing unit by a replenishment pump (not shown). The replenishment can be performed by measuring the plate length of the printing plate 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, an electric 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 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.

  The printing plate 12 that has entered the washing section from the washing entrance roller is sprayed with washing water by a spray 66 and discharged from the washing section by a roller pair 64.

  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.

  Spray pipes 66 and 68 are arranged in pairs between the conveying roller pairs 62 and 64 with the conveying path of the printing plate 12 interposed therebetween. A metal rod rod 67 for discharging liquid is disposed on the upper roller 62A of the conveying roller pair 62.

  For example, washing water (hereinafter referred to as “washing water”) is stored in the washing tank 26 as a cleaning agent. In the automatic developing device 10, spraying is performed in synchronization 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 the pipes 66 and 68. As a result, washing water is ejected from the spray tubes 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 the washing water from the spray pipes 66 and 68 is such that the spray pipe 66 is on the upstream side in the transport direction of the printing plate 12 and the spray pipe 68 is on the downstream side in the transport 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.

  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.

  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.

  In the finishing processing unit 18, a spray pipe 72 is provided above the transport path of the printing plate 12, and a spray pipe 74 is provided below the transport path. The spray tubes 72 and 74 are arranged vertically with the longitudinal direction (axial direction) along the width direction of the printing plate 12 and sandwiching the conveyance path of the printing plate 12. The spray tubes 72 and 74 are formed with a plurality of discharge holes along the width direction of the thermal positive printing plate 12.

  The finishing treatment tank 28 stores a gum solution used for protecting the plate surface of the printing plate 12, and the gum solution is supplied to the spray tubes 72 and 74 in synchronization with the conveyance of the printing plate 12. The spray tube 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 tube 74 discharges the gum solution from the ejection holes 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 conveyance 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 tube 74, a discharge unit or the like 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 evenly 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. I try to prevent it. 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 printing plate processor 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 thermal positive printing plate 12 and the discharge port 88. A conveying roller pair 90 and a conveying roller pair 92 are provided. The thermal positive printing plate 12 is transported in the drying unit 20 by a support roller 86 and a pair of transport rollers 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 thermal positive printing plate 12, and a slit hole 98 is provided on the 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.

  The shielding lid 100 is provided with a selection part (to be described later) together with a concave portion 100A into which the brush roller 142 and the conveying roller 60 project from the developer surface, and a roller above the conveying roller pair 52. A recess 100B into which a part 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 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.

  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 conveyance roller 48 and the conveyance 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 pair 52. The guide plate 48 guides the thermal positive printing plate 12 fed out by the transport roller pair 50 toward the transport roller pair 52 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. The guide is surely guided toward the transport roller pair 52.

Next, materials used for the development system will be described.
The photosensitive lithographic printing plate to which the alkali developing solution of the present invention can be applied is not particularly limited, and various lithographic printing plates in which an image recording layer such as a photosensitive layer and a heat-sensitive layer is provided on a support. List the original version. 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 negative type and the photopoly 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.

  The developer used in the present invention contains the following components. Developer (Alkaline Agent) The developer and developer replenisher used in the developing method of the present invention are alkaline aqueous solutions having a pH of 10.0 to 13.5, more preferably 11.0 to 13.3. Conventionally known alkaline aqueous solutions can be used as the developer and developer replenisher. For example, sodium silicate, potassium, tribasic sodium phosphate, potassium, ammonium, dibasic sodium phosphate, potassium, ammonium, sodium bicarbonate, potassium, ammonium, sodium carbonate, potassium, Examples include inorganic alkaline agents such as ammonium, sodium hydrogen carbonate, potassium, ammonium, sodium borate, potassium, ammonium, sodium hydroxide, ammonium, potassium, and lithium. Moreover, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, Organic alkali agents such as ethyleneimine, ethylenediamine, and pyridine are also used.

Among these alkali agents, aqueous silicate solutions such as sodium silicate and potassium silicate are preferred. The reason for this is that the ratio of pH and developability depends on the ratio (generally expressed as a molar ratio of [SiO ₂ ] / [M ₂ O]) and concentration of silicon oxide SiO ₂ and alkali metal oxide M ₂ O, which are silicate components. This is because adjustment is possible. For example, the molar ratio of SiO ₂ / Na ₂ O is 1.5 to 2.5 (that is, [SiO ₂ ] / [Na ₂ O] is 1.5 to 2.5), and the content of SiO ₂ is An alkali metal silicate composed of an aqueous solution of 1 to 4% by weight of sodium silicate is preferably used in the present invention.
A more preferable alkaline agent is a buffer solution composed of a weak acid and a strong base. The weak acid used as such a buffer is preferably one having an acid dissociation constant (pKa) of 10.0 to 13.3,

  In particular, those having a pKa of 11.0 to 13.1 are preferable. For example, in the case of sulfosalicylic acid, the third dissociation constant is 11.7, which can be suitably used in the present invention. That is, in the case of a polybasic acid, it can be used in the present invention if at least one acid dissociation constant is within the above range.

  Such a weak acid is selected from those described in IONATION CONSTANTS OF ORGANIC ACIDS INAQUEOUS SOLUTION issued by Pergamon Press, for example, 2,2,3,3-tetrafluoropropanol-1 (pKa 12.74), Alcohols such as trifluoroethanol (12.37) and trichloroethanol (12.24), and aldehydes such as pyridine-2-aldehyde (12.68) and pyridine-4-aldehyde (12.05) Sorbitol (13.0), sucrose (12.7), 2-deoxyribose (12.61), 2-deoxyglucose (12.51), glucose (12.46), galactose (same) 12.35), Ara Vinose (12.34), xylose (12.29), fructose (12.27), lipos (12.22), mannose (12.08), L-ascorbic acid (11.34) Sugars, salicylic acid (13.0), 3-hydroxy-2-naphthoic acid (12.84), catechol (12.6), gallic acid (12.4), sulfosalicylic acid (11. 7), 3,4-dihydroxysulfonic acid (12.2), 3,4-dihydroxybenzoic acid (11.94), 1,2,4-trihydroxybenzene (11.82), hydroquinone (same as above) 11.56), compounds having a phenolic hydroxyl group such as pyrogallol (11.34) and resorcinol (11.27), 2-butanone oxime (12.45), acetoxy (12.42), 1,2-cycloheptanedione dioxime (12.3), 2-hydroxybenzaldehyde oxime (12.10), dimethylglyoxime (11.9), ethanediamide dioxime (Id. 11.37), oximes such as acetophenone oxime (No. 11.35), 2-quinolone (No. 11.76), 2-pyridone (No. 11.65), 4-quinolone (No. 11.28), Amino acids such as 4-pyridone (11.12), 5-aminovaleric acid (10.77), 2-mercaptoquinoline (10.25), 3-aminopropionic acid (10.24), fluorouracil (13.0), guanosine (12.6), uridine (12.6), adenosine (12.56), inosine (12.5), guanine (12) 3) Nucleic acid-related substances such as Citidin (same as 12.2), Cytosine (same as 12.2), Topoxanthin (same as 12.1), Xanthine (same as 11.9), In addition, Diethylaminomethylphosphonic acid (same as 12) .32), 1-amino-3,3,3-trifluorobenzoic acid (12.29), isopropylidene diphosphonic acid (12.10), 1,1-ethylidene diphosphonic acid (11.54). ), 1-hydroxy 1,1-ethylidene diphosphonate (11.52), benzimidazole (12.86), thiobenzamide (12.8), picoline thioamide (12.55), barbituric acid ( And weak acids such as 12.5). Sodium hydroxide, ammonium, potassium and lithium are used as strong bases to be combined with these weak acids.

  These alkali agents are used alone or in combination of two or more. Of these alkaline buffers, sulfosalicylic acid, salicylic acid, saccharose and sorbitol are combined with sodium hydroxide and potassium hydroxide. Among them, a preferred combination is sorbitol and potassium hydroxide or sodium hydroxide. The above various alkali agents are used by adjusting the pH within a preferable range depending on the concentration and combination.

(Surfactant)
To the developer and replenisher used in the present invention, various surfactants and organic solvents can be added as necessary for the purpose of promoting developability, dispersing development residue, and improving ink affinity of the printing plate image area. Preferred surfactants include anionic, cationic, nonionic and amphoteric surfactants.

(Development stabilizer)
Various development stabilizers are used in the developer and replenisher used in the present invention. Preferred examples thereof include polyethylene glycol adducts of sugar alcohols described in JP-A-6-282079, tetraalkylammonium salts such as tetrabutylammonium hydroxide, phosphonium salts such as tetrabutylphosphonium bromide, and iodonium such as diphenyliodonium chloride. A salt is a preferred example.

(Organic solvent)
If necessary, an organic solvent is added to the developer and the development replenisher. As such an organic solvent, those having a solubility in water of about 10% by weight or less are suitable, and preferably those having a solubility in water of 5% by weight or less are selected. For example, 1-phenylethanol, 2-phenylethanol, 3-phenyl-1-propanol, 4-phenyl-1-butanol, 4-phenyl-2-butanol, 2-phenyl-1-butanol, 2-phenoxyethanol, 2- Benzyloxyethanol, o-methoxybenzyl alcohol, m-methoxybenzyl alcohol, p-methoxybenzyl alcohol, benzyl alcohol, cyclohexanol, 2-methylcyclohexanol, 3-methylcyclohexanol and 4-methylcyclohexanol, N-phenylethanol Examples thereof include amines and N-phenyldiethanolamine. The content of the organic solvent is 0.1 to 5% by weight with respect to the total weight of the used solution. The amount used is closely related to the amount of surfactant used, and it is preferable to increase the amount of surfactant as the amount of organic solvent increases. This is because the amount of the surfactant is small, and when the amount of the organic solvent is large, the organic solvent is not completely dissolved, so that it is impossible to expect good developability.

(Reducing agent)
A reducing agent is further added to the developer and replenisher used in the present invention. This prevents stains on the printing plate, and is particularly effective when developing a negative photosensitive lithographic printing plate containing a photosensitive diazonium salt compound. Preferable organic reducing agents include phenol compounds such as thiosalicylic acid, hydroquinone, metol, methoxyquinone, resorcin, and 2-methylresorcin, and amine compounds such as phenylenediamine and phenylhydrazine. More preferable inorganic reducing agents include sodium, potassium and ammonium salts of inorganic acids such as sulfurous acid, bisulfite, phosphorous acid, hydrogen phosphite, dihydrogen phosphite, thiosulfuric acid and dithionite. A salt etc. can be mentioned. Among these reducing agents, sulfites are particularly excellent in the antifouling effect. These reducing agents are preferably contained in the range of 0.05 to 5% by weight with respect to the developing solution at the time of use.

(Organic carboxylic acid)
An organic carboxylic acid can also be added to the developer and replenisher used in the present invention. Preferred organic carboxylic acids are fatty acid carboxylic acids and aromatic carboxylic acids having 6 to 20 carbon atoms. The amount added is from 0.1 to 10% by weight, more preferably from 0.5 to 4% by weight, based on the developing solution in use.

(Other)
The developer and replenisher used in the present invention may further contain an antifoaming agent, a hard water softening agent, and the like, if necessary. Examples of water softeners include polyphosphoric acid and its sodium, potassium and ammonium salts, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, triethylenetetraminehexaneacetic acid, hydroxyethylethylenediaminetriacetic acid, nitrilotriacetic acid, 1,2-diaminocyclohexanetetra Aminopolycarboxylic acids such as acetic acid and 1,3-diamino-2-propanoltetraacetic acid and their sodium, potassium and ammonium salts, aminotri (methylenephosphonic acid), ethylenediaminetetra (methylenephosphonic acid), diethylenetriaminepenta (methylene Phosphonic acid), triethylenetetramine hexa (methylenephosphonic acid), hydroxyethylethylenediaminetri (methylenephosphonic acid) Beauty diphosphonic acid and their sodium salts, potassium salts and ammonium salts. The optimum value of such a hard water softening agent varies depending on its chelating power, the hardness of the hard water used and the amount of hard water. % By weight, more preferably in the range of 0.01 to 0.5% by weight. If the addition amount is less than this range, the intended purpose is not sufficiently achieved. If the addition amount is more than this range, adverse effects on the image area such as color loss will occur.

  The remaining component of the developer and the replenisher is water, but various additives known in the art can be added as required. It is advantageous in terms of transportation that the developer and replenisher used in the present invention are concentrated solutions in which the water content is less than in use, and diluted with water during use. In this case, the degree of concentration is appropriate such that each component does not cause separation or precipitation. By using the developer as described above in the present invention, the occurrence of image defects and the like can be more significantly suppressed.

<Action>
The operation of the embodiment of the present invention will be described in detail below.
A printing plate processor 10 shown in FIG. 1 generally applies a gum solution to a developing unit 14 for processing a photosensitive lithographic printing plate with a developer, a washing unit 16 for washing with water, and a lithographic printing plate after washing. A finisher unit 18 for desensitizing treatment and a drying unit 20 for drying the lithographic printing plate coming out of the finisher unit are disposed.

  As described above, when the planographic printing plate is processed, the photosensitive layer on the planographic printing plate is eluted in the developer. The photosensitive layer contains dyes or pigments, and these dyes or pigment components are contained in the developing solution in accordance with the development process. After replacement of the developer, the dye and pigment components in the developer are not large in the situation close to the new solution, but as the substitution rate increases, the dye and pigment components in the developer become large. On the other hand, since the developing solution temperature is kept constant by heating means such as a heater, when the developing process proceeds, the developing solution containing the photosensitive layer component (developing fatigue solution) is heated by the heater. Become. Usually, the developer temperature is set higher than room temperature, and in order to process with the developer, it is essential to warm the developer. In particular, when the developing machine is switched from the stopped state to the operating state, the developing solution lowered to near room temperature is continuously heated for a long time.

  In a situation where the developer is heated by the heater, the developer is locally at a high temperature in the vicinity of the heater surface, and a dye or pigment contained in the developer is deposited on the heater. In the developer, the dye and pigment components are often in a dispersed state. In such a case, the dispersion of the dye or pigment is often destroyed by heat and deposited.

Furthermore, the dye and pigment components thus deposited peel off into the developer and adhere to the plate during plate passing, causing image defects. Moreover, since deposits adhere to the developing unit heater, a load is imposed on cleaning and maintenance after the processing is completed.
The heater surface temperature can also be realized by lowering the heat generation amount, but it hinders the rise of the developer temperature. Although it is possible to cope with this by increasing the surface area, it is desirable to make the heater part in the developing tank as compact as possible. Therefore, in order to lower the heater surface temperature without lowering the heating capacity of the developing solution, there is no other way than increasing the heat exchange performance in the vicinity of the heater. Until now, the liquid circulation was poor around the heater, and the heater surface temperature was significantly increased.

Therefore, a liquid flow is provided in the heater direction to suppress the surface temperature of the heater as much as possible. The heater surface temperature at which the precipitate is generated varies depending on the composition of the developer, but it is usually desirable to suppress it to 80 ° C. or lower.
The liquid flow provided around the heater is formed by attaching a sufficiently long guide cover and sucking from a part. By appropriately adjusting the length of the guide cover and the distance between the heater and the guide cover, the heater surface temperature can be suppressed, and the generation of precipitates on the heater can be sufficiently suppressed.

<Examples and comparative examples>
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.

In the self-described machine described in detail in FIG. 1, the initial charge developer DT-2 (developer for thermal positive manufactured by Fuji Photo Film Co., Ltd.) was diluted 1: 8 with water and charged. As a replenisher, DT-2R diluted 1: 6.5 was used. The development conditions are a developer temperature of 30 degrees and a development time of 12 seconds. Water was added to the washing section, and finisher FG-1 (diluted 1: 1) manufactured by Fuji Photo Film Co., Ltd. was added to the finishing section. The lithographic printing plate precursor HP-S was exposed and developed at a processing amount of 60 m ² / day, and the deposition of deposits on the heater after about 3 months and image defects during plate making were evaluated. As a result, it became as shown in Table 1.

In Table 1, Examples 1 to 6 are examples in which a guide cover is attached on the heater as shown in FIG. 2, and Examples 1, 2, and 5 have a constant distance (5 mm) between the heater surface and the guide cover. The length of the exposed portion where the heater surface is not covered with the guide cover is changed, and Example 1 = 10 cm, Example 2 = 20 cm, and Example 5 = 23 cm. In Examples 3, 4, and 6, the length of the exposed portion where the heater surface is not covered with the guide cover is constant (10 cm), and the distance between the heater surface and the guide cover is changed. Example 3 = 10 mm 4 = 15 mm, Example 6 = 17 mm.
On the other hand, Comparative Example 1 is a conventional heater in which no guide cover is attached on the heater.

It can be seen from Table 1 that Examples 1 and 3 had no deposits deposited on the heater, and therefore there were no image defects. Examples 2 and 4 had almost no deposits deposited on the heater and therefore no image defects. In Examples 5 and 6, the deposit adhered to the heater was slightly scattered, but it was not an image defect and was acceptable. In either case, the state as shown in FIG. 4A or close to this was maintained.
On the other hand, in Comparative Example 1, as shown in FIG. 4B, deposits were observed on the heater, and thus image defects were seen in 5 out of 10 plates.
As described above, according to the present invention, even when the photosensitive lithographic printing plate is processed for a long period of time, there is no deposit on the developing unit heater and there is no deposit, and image defects due to the deposit do not occur.

As described above, according to the present invention, a liquid in which a solid content is dissolved or dispersed is placed in a container having a discharge port and a liquid suction port, and is circulated through the discharge port and the liquid suction port. In the liquid heating method of heating with a heater, a heater that is heated in a state of being immersed in the liquid is covered with a guide cover, and liquid is absorbed from a part of the guide cover, whereby the space between the guide cover and the surface of the heater is increased. Since a liquid flow is formed in the gap formed in the above, even if the lithographic printing plate coated with the photosensitive material is image-recorded by the material exposure means and developed, and the number of processed printing plates Even if the amount of the toner increases, no precipitate is generated on the surface of the heater for heating the developer, so that the precipitate deposited on the surface of the heater does not fall off. Is now Eliminates also any adhere to the planographic printing plate in the floating or development in a liquid, which by the image defect problem was solved.
Further, since deposits do not adhere to the developing section heater, cleaning and maintenance after the processing is reduced.

1 is an overall configuration diagram of a printing plate processor including a developing unit according to a first embodiment of the present invention. FIG. 2 is an enlarged perspective view showing the vicinity of the heater portion of FIG. 1, (a) is a state in which a guide cover for covering the heater side surface is removed from the heater, and (b) is a guide cover from the tip of the heater to the heater root. The state where it was installed in the form of covering each is shown. It is an expansion perspective view which shows the heater site | part vicinity of the conventional apparatus. It is a perspective view which shows the condition of the heater surface when the number of processed printing plates increases, (a) shows the apparatus according to the present invention, and (b) shows the conventional apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Printing plate processor 12 Printing plate 14 Developing part 16 Washing part 18 Finishing (desensitizing) processing part 20 Drying part 22 Processing tank 22a Liquid suction port 24 Developer tank 26 Washing tank 28 Finishing processing tank 30 Outer panel 32 Insert port 34 Insertion portion 36 Insertion port side cover 38 Drying portion side cover 40 Reentry insertion port (sub insertion port)
42, 48, 50, 52 Conveying roller pair 54, 56 Spray tube 60 Conveying roller 62A Smoothing rollers 62B, 62B2 Convex roller 62B1 Grooving roller 64 Conveying roller pair 66, 68 Spray tube 200 Bar heater 202 Circulating guide cover

Claims (7)

  In a liquid heating method in which a liquid in which a solid content is dissolved or dispersed is placed in a container having a discharge port and a liquid suction port and heated by a heater while circulating through the discharge port and the liquid suction port, Covering the heater that is heated in an immersed state with a guide cover, and sucking liquid from a part of the guide cover, thereby forming a liquid flow in a gap formed between the surface of the guide cover and the heater. A liquid heating method characterized by the above.   2. The liquid heating method according to claim 1, wherein the liquid is a processing solution used when processing a photosensitive material.   2. The liquid heater according to claim 1, wherein the heater is rod-shaped, and the liquid heater circulates by covering the rod-shaped heater with a cylindrical guide cover and sucking the liquid from one side of the cylindrical guide cover. 3. The liquid heating method according to 2.   In a liquid heating apparatus in which a liquid in which a solid content is dissolved or dispersed is placed in a container having a discharge port and a liquid suction port and heated by a heater while being circulated through the discharge port and the liquid suction port, A guide cover that covers the heater that is heated in an immersed state, and a liquid absorption that forms a liquid flow in a gap formed between the surface of the guide cover and the heater by performing liquid absorption from a part of the guide cover And a liquid heating apparatus.   5. The liquid heating apparatus according to claim 4, wherein the liquid is a processing solution used when processing a photosensitive material.   The said heater is a rod heater, the circumference of the rod heater is covered with a cylindrical guide cover, and the liquid is circulated by sucking the liquid from one side of the cylindrical guide cover. The liquid heating apparatus according to 4 or 5.   The liquid heating apparatus according to claim 4, wherein the cylindrical guide cover is detachably provided.

Images