JP6580775B1 - Filter, dampening water circulation system, and dampening water circulation method - Google Patents

Abstract

To provide a filter capable of easily reducing foreign substances contained in dampening water. A filter is provided in a circulation system that circulates dampening water for offset printing. The filter 10 includes a melamine resin foam 12 that filters the fountain solution 71 and gravity-filters the fountain solution. The filter 10 includes a melamine resin foam 12, a main body having an opening for taking in and taking out the melamine resin foam 12, and a lid that covers the opening. [Selection] Figure 1

Description

  The present disclosure relates to a filter, a dampening water circulation system, a dampening water circulation method, a melamine resin foam, and a method of using the same.

  The fountain solution used for offset printing is usually circulated. This dampening water is mixed with paper powder, dust, oil, powder, and the like from the printing plate. In order to purify such fountain solution, a technique for providing a potential adsorption filter device in the fountain solution circulation system has been proposed. Attempts have been made to reduce the replacement frequency of dampening water using such a technique (see, for example, Patent Document 1).

  On the other hand, for the production of a printing plate, image exposure and development are performed using CTP (computer to plate) technology. Recently, in order to improve work efficiency, a technology is known in which, after exposure, the image recording layer (photosensitive layer) is attached to a printing machine without being subjected to development processing, and unnecessary portions of the image recording layer (photosensitive layer) are removed with a dampening water of the printing machine. It has been. Under such circumstances, a component containing a water-soluble polymer or the like as a component of the fountain solution has been studied (for example, see Patent Document 2).

Japanese Patent Laid-Open No. 2003-211625 JP 2011-51228 A

  In the dampening water for offset printing, not only conventional foreign matters such as paper dust and dust but also foreign matters such as resin components derived from the photosensitive layer are increasing. When such foreign matter increases, the frequency of occurrence of printing defects, the clogging frequency of the conventional potential adsorption filter, and the replacement frequency increase.

  Then, this indication provides the filter which can reduce the foreign material contained in dampening water simply. In addition, the present disclosure provides a dampening water circulation system and a dampening water circulation method that can easily reduce foreign substances contained in the dampening water by having the filter. Moreover, this indication provides the melamine resin foam which can reduce the foreign material contained in dampening water simply, and its usage method.

  The filter of this indication is a filter provided in the circulation system which circulates the dampening water of offset printing, and is provided with the melamine resin foam which filters dampening water. The melamine resin foam has a network-like three-dimensional crosslinked structure. In this melamine resin foam, when the fountain solution is filtered, foreign substances are trapped in the network-like three-dimensional cross-linked structure. Since the melamine resin foam is excellent in water absorption and is easy to process and handle, foreign substances contained in the fountain solution can be easily reduced.

  A plurality of sheet-like melamine resin foams may be laminated on the filter. By making it into a sheet shape, the filtration area can be increased. Moreover, by laminating a plurality, it is possible to suppress the passage of the resin component and to sufficiently capture the resin component.

  The filter is preferably gravity filtered for dampening water. Since the melamine resin foam has high hydrophilicity, the fountain solution can be gravity filtered. As a result, there is no need to provide a pressurizing or depressurizing pump, a seal portion, and the like, so that the configuration of the dampening water circulation system can be simplified. Moreover, the deformation | transformation of the melamine resin foam accompanying pressurization or pressure reduction is reduced, and the failure | damage of a melamine resin foam can be suppressed.

  The said filter may be equipped with the molded object of the fiber holding a melamine resin foam. The melamine resin foam may break when deformed greatly. On the other hand, the fiber molded body can be deformed larger than the melamine resin foam and is not easily broken. For this reason, even if the melamine resin foam is deformed and broken, the shape of the melamine resin foam is held by the fiber molded body. For this reason, it can suppress that the melamine resin foam after a fracture | rupture falls apart, and it can suppress that the filtration performance of a melamine resin foam is impaired greatly. Moreover, even if a broken piece of the melamine resin foam is generated, the broken piece can be prevented from flowing out to the downstream side.

  The filter includes a melamine resin foam, a main body having an opening for taking in and taking out the melamine resin foam, and a lid that covers the opening, and the lid is provided with dampening water. The main body may have an introduction port that introduces the fountain solution filtered by the melamine resin foam at the lower portion. Such a filter can easily exchange the melamine resin foam through the opening by opening the lid.

  The present disclosure provides a dampening water circulation system having a dampening water circulation passage having the filter described above. Since this circulation system includes the above-described filter in the circulation channel, foreign substances contained in the fountain solution can be easily reduced.

  This circulation system includes a printing press and a potential adsorption filter having a zeta potential adsorption action, which is different from a filter. When the circulation channel is viewed from the printing press, the upstream side of the potential adsorption filter. May be equipped with a filter. Such a potential adsorption filter can capture small foreign substances (for example, foreign substances such as paper powder and dust) that are difficult to be captured by the melamine resin foam. As a result, the amount of foreign matter in the dampening water can be further reduced, and the occurrence of printing defects can be more reliably reduced. Moreover, since the filter is provided on the upstream side of the potential adsorption filter with reference to the printing press, it is possible to prevent the potential adsorption filter from being blocked by a large foreign substance (for example, resin component). For this reason, the replacement frequency of the potential adsorption filter more expensive than the melamine resin foam can be reduced.

  The present disclosure provides a method for circulating dampening water that is supplied to a printing press while circulating dampening water, and includes a step of filtering dampening water with a melamine resin foam. . In this circulation method, since the fountain solution is filtered by the melamine resin foam, foreign substances contained in the fountain solution can be easily reduced.

  The present disclosure provides a melamine resin foam for filtering offset dampening water. The melamine resin foam has a network-like three-dimensional crosslinked structure. When the fountain solution is filtered with the melamine resin foam, foreign substances are trapped in the network-like three-dimensional crosslinked structure. Since the melamine resin foam is excellent in water absorption and is easy to process and handle, foreign substances contained in the fountain solution can be easily reduced.

  The present disclosure provides a method of using a melamine resin foam that uses the melamine resin foam for dampening water in offset printing. In this method of use, since the fountain solution is filtered by the melamine resin foam, the resin component contained in the fountain solution can be easily reduced.

  According to the present disclosure, it is possible to provide a filter that can easily reduce foreign substances contained in the fountain solution. In addition, according to the present disclosure, it is possible to provide a dampening water circulation system and a dampening water circulation method that can easily reduce foreign substances contained in the dampening water by having the filter. it can. Moreover, according to this indication, the melamine resin foam which can reduce the foreign material contained in dampening water simply, and its usage method can be provided.

It is a figure which shows the outline | summary of the circulation system of dampening water. It is a perspective view which shows an example of a melamine resin foam. It is sectional drawing which shows an example of a filter.

  Hereinafter, embodiments of the present disclosure will be described below with reference to the drawings as the case may be. However, the following embodiments are examples for explaining the present disclosure, and are not intended to limit the present disclosure to the following contents.

  FIG. 1 is a diagram illustrating an outline of a dampening water circulation system according to an embodiment. A dampening water circulation system 100 shown in FIG. 1 includes a printing press 60 having a water boat 70 and a circulation flow path 50 for circulating dampening water to the water boat 70. When the circulation channel 50 is viewed from the water boat 70 of the printing press 60, the filter 10, the intermediate tank 20, the first pump 40, the dumpling tank 22, the filter device 25 connected thereto, and the first Two pumps 42 are provided in this order. Each device is connected by piping.

  The printing press may be an offset rotary printing press that performs offset printing, but is not limited thereto, and may be a sheet-fed printing press, a business form rotary printing press, or an offset newspaper rotary printing press. The printing press 60 as an example includes, for example, a plate cylinder 65 around which a plate is wound, and water rollers 61, 62, and 63 that supply dampening water to the plate cylinder 65. In addition to these members, the printing press 60 may include an ink roller, a blanket copper for transferring the ink of the printing plate wound around the plate cylinder 65, and an impression cylinder. The printing plate may be manufactured by, for example, CTP (Computer to Plate). For example, it is manufactured by exposing a PS plate coated with a photosensitive layer containing a resin to form an image recording layer.

  The printing press 60 includes a water boat 70 that stores dampening water 71. A part of the water roller 61 rotates while being immersed in the dampening water 71 of the water boat 70, so that the dampening water 71 adheres to the rotating surface. The adhering dampening water 71 is supplied to the printing plate wound around the plate cylinder 65 via the water roller 62 and the water roller 63. Resin components such as paper powder, pigment, ink, and the like adhering to the printing plate and foreign matters such as dust are taken into the fountain solution 71 and flow down to the water boat 70. In the case of development-less (on-press development) in which the printing plate is not subjected to wet development processing, in addition to paper dust and dust, the dampening water 71 contains a resin component derived from the photosensitive layer.

  The fountain solution 71 in the water boat 70 containing a resin component in addition to paper powder and dust etc. is introduced into the filter 10 through the pipe 30 connected to the water boat 70. The filter 10 includes a melamine resin foam 12 that filters the fountain solution 71. The melamine resin foam 12 has a network-like three-dimensional cross-linking structure and is composed of fine cells. The melamine resin foam 12 is excellent in water permeability, but can be easily processed into a cell size suitable for capturing the resin component, and is therefore suitable as a filter medium for filtering fountain solution containing foreign matters containing the resin component. Can be used.

  The cell diameter (cell diameter) may be, for example, 10 to 800 μm, 30 to 600 μm, or 50 to 300 μm. The cell diameter can be determined from a 750-fold observation image using a commercially available microscope. Arbitrary 10 cells can be selected and measured at different locations to obtain an arithmetic average value. Among the foreign matters contained in the fountain solution, foreign matters having a small size (for example, solid content different from resin components such as paper powder and dust) may pass through the melamine resin foam 12. These foreign substances can be removed by the filter device 25.

  The 25% compressive strength of the melamine resin foam 12 may be, for example, 2 to 15 kPa, or 3 to 10 kPa. The 25% compressive strength can be obtained by a “6.7 D method (a method for obtaining a force after 20 seconds after constant compression at 25%)” in JIS K 6400-2 using a commercially available measuring device.

  The melamine resin foam 12 mainly captures the resin component contained in the fountain solution 71. The opening of the melamine resin foam 12 may be larger than the potential adsorption filter used in the filter device 25 or the like. Thereby, a large foreign substance (for example, a resin component derived from the photosensitive layer) contained in the fountain solution 71 can be efficiently captured. In the melamine resin foam 12, it is not necessary to capture all of the foreign matter.

The density of the melamine resin foam 12 may be, for example, 7 to 11 kg / m ³ . The melamine resin foam 12 is a flexible foam and can be manufactured by a known method. For example, first, components such as an emulsifier and a curing agent are added to a resin composition containing a melamine formaldehyde condensate and a foaming agent, and heated to the boiling point or higher of the foaming agent. Thus, the foam obtained by foaming can be cured to obtain the melamine resin foam 12. The manufacturing method of the melamine resin foam 12 is not limited to this. The melamine resin foam 12 may be a commercially available product. For example, BASF's Basotect / Bazotect (registered trademark) can be used.

  FIG. 2 is a perspective view showing an example of a melamine resin foam. As shown in FIG. 2, the melamine resin foam may be in the form of a sheet. The thickness of the melamine resin foam along the flow direction of the fountain solution 71 is preferably 10 mm or more and more preferably 20 mm or more from the viewpoint of sufficiently capturing foreign matter in the fountain solution. The upper limit of the thickness may be 500 mm, for example. A plurality of sheet-like melamine resin foams having the above-described thickness may be stacked and installed in the filter 10. That is, the filter 10 may include a laminate of melamine resin foams.

  FIG. 3 is a cross-sectional view showing an example of a filter. The filter 10 of FIG. 3 includes a main body 10A that accommodates the melamine resin foam 12 and the fiber molded body 13, and a lid 10B that covers the upper opening of the main body 10A. If the lid 10B is opened, the melamine resin foam 12 and the fiber molded body 13 can be taken in and taken out from the opening of the main body 10A. Thereby, the exchange operation | work of the melamine resin foam 12 and the molded object 13 can be performed simply. A set of gripping portions 16 is attached to the lid portion 10B to facilitate the opening operation.

  Inside the filter 10, four sheet-like melamine resin foams 12a, 12b, 12c, and 12d are stacked and installed in this order as the melamine resin foam 12. Each of the sheet-like melamine resin foams 12a, 12b, 12c, and 12d has a shape as shown in FIG. 2, for example. By laminating a plurality of melamine resin foams along the flow direction of the fountain solution, foreign substances contained in the fountain solution 71 can be sufficiently captured. The number of sheet-like melamine resin foams is not limited to four, but may be five or more, or may be three or less. From the viewpoint of sufficiently capturing foreign matter, it is preferable to stack four or more, more preferably six or more.

  A molded body 13 for holding the melamine resin foam 12 is installed below the melamine resin foam 12d at the lowermost part of the melamine resin foam 12. The molded body 13 is composed of fibers different from the melamine resin foam 12. The fiber may be natural fiber or chemical fiber. Natural fibers include cotton or wool. On the other hand, examples of the chemical fiber include polyester, nylon, polyurethane, acrylic, aramid, vinylon, and polyvinyl chloride fiber.

  The thickness of the molded body 13 is preferably 10 mm or more and more preferably 20 mm or more from the viewpoint of maintaining strength. The upper limit of the thickness may be 500 mm, for example.

  The molded body 13 may be a compression molded body obtained by compression molding a fiber. Such a molded body 13 can be deformed larger than the melamine resin foam 12. For this reason, even if the melamine resin foam 12 is deformed and damaged, the shape is held by the molded body 13 without falling apart. For this reason, it can suppress that the filtration performance of the filter 10 is impaired greatly. Moreover, it can suppress that the fragment of the melamine resin foam 12 flows out to the downstream side of the filter 10.

  The filter 10 includes a support 14 on the lower side of the molded body 13. The support 14 may be, for example, a metal punching plate or a metal mesh. The support 14 suppresses deformation of the melamine resin foam 12 and the molded body 13.

  The lid 10 </ b> B of the filter 10 has an introduction port 18 through which dampening water 71 is introduced at the center. The piping 30 of FIG. 1 may be connected to the introduction port 18, or the lower end of the piping 30 of FIG. 1 may be inserted. The fountain solution 71 may fall from the water boat 70 by gravity and be introduced into the filter 10 through the inlet 18. The filter 10 can filter only by gravity without pressurizing the fountain solution 71 with a pump or the like (gravity filtration). Since the filter 10 can gravity filter the dampening water 71, the apparatus configuration can be simplified and the required power can be reduced. Moreover, the deformation | transformation and damage of the melamine resin foam 12 and the molded object 13 can be suppressed, and filtration performance can be maintained over a long period of time. However, in another embodiment, for example, the piping 30 may be filtered by providing a pressurizing means such as a pump.

  The main body 10A of the filter 10 has a relief pipe 15 above the side. As a result, the dampening water can be prevented from flowing back into the pipe 30. The escape pipe 15 may be connected to the intermediate tank 20 or the dump ring tank 22, for example. Normally, the dampening water does not flow out from the escape pipe 15. When the melamine resin foam 12 is blocked and it becomes difficult for the fountain solution to pass through, the fountain solution flows out from the escape pipe 15. At this timing, the melamine resin foam 12 accommodated in the filter 10 and the molded body 13 may be replaced as necessary.

  The main body portion 10 </ b> A has a lead-out port 19 through which fountain solution that has passed through the melamine resin foam 12 and the molded body 13 is led out. A pipe 32 in FIG. 1 is connected to the outlet 19. The fountain solution is introduced into the intermediate tank 20 through the pipe 32. The intermediate tank 20 functions as a buffer tank, for example. The dampening water stored in the intermediate tank 20 has a sufficiently reduced resin component content than the dampening water before being filtered by the filter 10.

  The dampening water once stored in the intermediate tank 20 is led out from the intermediate tank 20 by the first pump 40, flows through the pipe 34, and is introduced into the dump ring tank 22. A filter device 25 is connected to the dump ring tank 22. For example, the filter device 25 may be a filter capable of capturing foreign matters finer than the melamine resin foam 12. Such a filter may be, for example, a potential adsorption filter having a zeta potential adsorption action. A small foreign substance (paper powder, dust, etc.) contained in the fountain solution that cannot be captured by the filter 10 is captured by the potential adsorption filter. As a result, the amount of foreign matter in the dampening water can be further reduced, and the occurrence of printing defects can be more reliably reduced.

  In the dampening water circulation system of another embodiment, the filter device 25 may not be provided. Even in this case, since the foreign matter in the dampening water is captured by the melamine resin foam, the occurrence of printing defects can be reduced.

  The dampening water circulation system 100 includes the filter 10 on the upstream side of the potential adsorption filter with respect to the printing press 60. For this reason, it can suppress that an electric potential adsorption filter obstruct | occludes with a foreign material (for example, resin component) with a big size. Therefore, the replacement frequency of the potential adsorption filter that is more expensive than the melamine resin foam 12 can be reduced. It is not always essential that the filter device 25 has a potential adsorption filter. For example, a pleated filter or a filter press may be used.

  The dampening water whose foreign matter has been reduced by the filter device 25 is led out from the dumpling tank 22 by the second pump 42, flows through the pipe 36, and is introduced into the water boat 70 of the printing press 60. In this way, the fountain solution is recycled. Since the fountain solution introduced into the water boat 70 has a sufficiently reduced content of foreign matter, it is possible to sufficiently suppress printing defects. When the amount of dampening water decreases due to evaporation or the like, dampening water may be replenished, for example, in the dumpling tank 22 or the intermediate tank 20.

  It is not essential for the filter 10 to include a plurality of sheet-like melamine resin foams 12. Moreover, in the modification of this embodiment, the melamine resin foam 12 may be directly supported by the support body 14 without providing the fiber molded body 13. Since the melamine resin foam 12 is excellent in water absorption and easy to process and handle, foreign substances contained in the fountain solution can be easily reduced.

  The dampening water circulation system 100 of the present embodiment is particularly useful when the printing plate is a type that cleans the photosensitive layer (the portion that does not become the image recording layer) of the printing plate with dampening water. Since the resin component derived from the photosensitive layer is mixed in such fountain solution, if the foreign matter in the fountain solution is removed only with the conventional potential adsorption filter, the frequency of replacing the potential adsorption filter increases. However, since the dampening water circulation system 100 of the present embodiment filters the dampening water using the melamine resin foam in the filter 10, the resin component that is a foreign substance having a large size of the comparative body is melamine resin. It will be trapped in the three-dimensional crosslinked structure of the foam. In the filter device 25, since the dampening water filtered by the filter 10 is filtered by the potential adsorption filter, the resin component adsorbed by the potential adsorption filter is sufficiently reduced, and the blockage of the potential adsorption filter by the resin component is suppressed. can do.

  Next, a method for circulating the dampening water according to one embodiment will be described. The dampening water circulation method may be performed using the dampening water circulation system 100 or may be performed using another system. The dampening water circulation method of the present embodiment is a dampening water circulation method for circulating dampening water for offset printing, and the dampening water derived from the water fountain of the printing press is filtered with a melamine resin foam. A first filtration step, a second filtration step of filtering the fountain solution filtered by the melamine resin foam with a potential adsorption filter having an adsorption action of zeta potential, and the fountain solution filtered by the potential adsorption filter. And a circulation process for returning to the boat. The description of the filter 10 and the dampening water circulation system 100 described above can be applied to the dampening water circulation method.

  In the first filtration step, the dampening water may be filtered by gravity filtration. Thereby, deformation of the melamine resin foam is suppressed, and damage to the melamine resin foam is suppressed. In addition, the driving operation can be simplified. In the first filtration step, of the foreign matter contained in the fountain solution by the melamine resin foam, a foreign matter having a large size (for example, a resin component) is captured in the network-like three-dimensional crosslinked structure.

  On the other hand, most of hard solids such as paper powder and dust smaller than the resin component may pass through the melamine resin foam without being captured. By performing the first filtration step before the second filtration step, the potential adsorption filter can be prevented from being clogged with the resin component. The first filtration step can be performed, for example, using a filter 10 in which a plurality of melamine resin foams as shown in FIG. 3 are stacked. As described above, the filter 10 may include a fiber molded body that holds the melamine resin foam.

  In the second filtration step, the fountain solution filtered with the melamine resin foam is filtered with a potential adsorption filter having a zeta potential adsorption action. A commercially available potential adsorption filter can be used. With this potential adsorption filter, foreign matter that has not been captured in the first filtration step is adsorbed to reduce the content of foreign matter in the fountain solution. Thus, the foreign material containing the resin component contained in the fountain solution can be efficiently reduced.

  The dampening water circulation method of the present embodiment is particularly useful when the printing layer (PS plate) is a type of printing machine (development-less or on-press development) in which the photosensitive layer containing the resin is washed with dampening water. is there. Since the resin component derived from the photosensitive layer is mixed in such fountain solution, if the foreign matter in the fountain solution is removed only with the conventional potential adsorption filter, the frequency of replacing the potential adsorption filter increases. However, in the dampening water circulation method of the present embodiment, since the dampening water is filtered using the melamine resin foam in the first filtration step, a large foreign matter (for example, resin component) is foamed with the melamine resin. It will be trapped in the three-dimensional crosslinked structure of the body.

  In the second filtration step, since the dampening water filtered in the first filtration step is filtered by the potential adsorption filter, the resin component adsorbed on the potential adsorption filter is sufficiently reduced, and the potential adsorption filter is blocked by the resin component. Can be suppressed. Therefore, it is extremely useful as a method of circulating offset dampening water. In addition, it is not essential to perform a 2nd filtration process, and if it has a 1st filtration process, the foreign material contained in dampening water can be reduced easily.

  The method of using the melamine resin foam in which the melamine resin foam according to the embodiment is used for filtration of dampening water for offset printing may be performed using the filter 10 or the dampening water circulation system 100 described above. This usage method may include the first filtration step or the first filtration step and the second filtration step. The description contents of the filter 10 and the dampening water circulation system 100 and the dampening water circulation method can be applied to the method of using the melamine resin foam.

  As mentioned above, although embodiment of this indication was described, this indication is not limited to the above-mentioned embodiment. For example, the filter 10 may have one melamine resin foam instead of the plurality of sheet-like melamine resin foams 12a, 12b, 12c, and 12d. The fiber molded body 13 may not be provided. The dampening water circulation system 100 may not include at least one of the intermediate tank 20, the dump ring tank 22, and the filter device 25.

  Although the content of this indication is explained in detail using an example and a comparative example, this indication is not limited to the following example.

Example 1
Eight sheets of sheet-like melamine resin foam (manufactured by BASF, trade name: BASOECT * G +, length × width × thickness = 260 mm × 480 mm × 30 mm) as shown in FIG. 2 were prepared. Eight of these were laminated | stacked along the thickness direction, and the filter as shown in FIG. 3 was produced. A raw material liquid (opaque) prepared by mixing ink with water was dropped from the inlet of the filter, and gravity filtration was performed. The filtrate obtained from the outlet was collected with a transparent glass (about 200 ml) and visually confirmed. The filtrate was almost transparent although it was slightly black. From this, it was confirmed that the components of the ink were sufficiently captured by the melamine resin foam.

(Comparative Example 1)
Instead of the melamine resin foam of Example 1, eight compression molded articles obtained by compression molding polyester fibers were prepared. This compression-molded body had the same size as the sheet-like melamine resin foam of Example 1. Eight of these were laminated along the thickness direction, and a filter was produced in the same manner as in Example 1. The raw material liquid (opaque) was subjected to gravity filtration in the same manner as in Example 1, and the filtrate obtained from the outlet was visually confirmed. As a result, the filtrate was almost the same black color as the raw material liquid and was opaque. From this, it was confirmed that only the compression molded body of the polyester fiber could not sufficiently capture the components of the ink.

(Comparative Example 2)
Instead of the melamine resin foam of Example 1, 8 rigid polyurethane foams were prepared. The rigid polyurethane foam had the same size as the sheet-like melamine resin foam of Example 1. Eight of these were laminated along the thickness direction, and a filter was produced in the same manner as in Example 1. When gravity filtration of the raw material liquid (opaque) was attempted in the same manner as in Example 1, the raw material liquid almost did not penetrate into the rigid polyurethane foam, and filtration was not possible.

(Example 2)
Using a dampening water circulation system as shown in FIG. 1 equipped with a Kikuzen full-size offset sheet-fed printing machine (development-less, number of colors: 8 colors, UV ink specification) manufactured by Komori Corporation. Tested. In this dampening water circulation system, two filters 10 were provided, and dampening water derived from the four color water boats was filtered by each filter 10. In each filter 10, three melamine resin foams used in Example 1 were stacked and accommodated. The filter device 25 is provided with a potential adsorption filter having a zeta potential adsorption action.

  The operating conditions of the printing press were continuous operation for 24 hours, the number of plate changes per day was 40 to 50 times, and the processing was a speed of 12,000 to 15,000 sheets / hour. Printing was performed under such operating conditions, and the replacement frequency of the potential adsorption filter was evaluated based on the change in the differential pressure between the inlet and the outlet in the filter device 25. As a result, the dampening water circulation system of Example 2 was able to operate continuously for about three months without replacing the potential adsorption filter and the melamine resin foam.

(Comparative Example 3)
Except not having the filter 10, the replacement frequency of the potential adsorption filter was evaluated under the same operating conditions as in Example 2 using a dampening water circulation system having the same configuration as in Example 2. As a result, in the dampening water circulation system of Comparative Example 3, the differential pressure increase in the filter device 25 was faster than in Example 2, and the necessity to replace the potential adsorption filter occurred in about 3 weeks. From this, it was confirmed that the comparative example 3 causes a significant cost increase and an increase in work load as compared with the example 2.

  In Example 2, among the foreign matters contained in the fountain solution in the filter 10, the resin component from the printing plate (PS plate) could be effectively removed by the melamine resin foam of the filter 10. As a result, it was confirmed that it is possible to extend the life of the potential adsorption filter in the filter device 25 and perform continuous operation, thereby realizing cost reduction and work load reduction. Moreover, small foreign matters that could not be captured by the melamine resin foam could be captured by the potential adsorption filter. For this reason, printing defects did not occur at all.

  Provided is a filter capable of easily reducing foreign substances contained in dampening water. Moreover, by having the said filter, the circulation system of the dampening water and the dampening water circulation method which can reduce the foreign material contained in dampening water simply can be provided. Moreover, the melamine resin foam which can reduce the foreign material contained in dampening water simply, and its usage method can be provided.

  DESCRIPTION OF SYMBOLS 10 ... Filter, 10A ... Main-body part, 10B ... Lid part, 12, 12a, 12b, 12c, 12d ... Melamine resin foam, 13 ... Molded body, 14 ... Support body, 15 ... Relief pipe, 16 ... Gripping part, DESCRIPTION OF SYMBOLS 18 ... Inlet port, 19 ... Outlet port, 20 ... Intermediate tank, 22 ... Dump ring tank, 25 ... Filter device, 30, 32, 36 ... Piping, 40 ... First pump, 42 ... Second pump, 50 ... Circulating flow Road, 60 ... Printing machine, 61, 62, 63 ... Water roller, 65 ... Plate cylinder, 70 ... Water boat, 71 ... Dampening water, 100 ... Circulation system.

Claims (14)

A filter provided in a circulation system for circulating offset printing dampening water,
A melamine resin foam for filtering the fountain solution;
The forming of fibers for holding the melamine resin foam, Filtration vessel to Ru with a.   The filter according to claim 1, wherein a plurality of sheet-like melamine resin foams are laminated.   The filter according to claim 1 or 2, wherein the dampening water is gravity filtered. A main body having an opening that accommodates the melamine resin foam and takes in and out the melamine resin foam, and a lid that covers the opening,
The lid has an inlet for introducing the fountain solution into the main body,
The said main-body part is a filter as described in any one of Claims 1-3 which has the outlet in which the said fountain solution filtered by the said melamine resin foam is guide | induced in the lower part. A filter provided in a circulation system for circulating dampening water for offset printing using a development-less PS plate,
A melamine resin foam for filtering the fountain solution ;
Filter comprising, a shaped body of fibers to hold the melamine resin foam. A dampening water circulation system comprising a dampening water circulation passage having the filter according to any one of claims 1 to 5 . A dampening water circulation system comprising a circulation flow path for circulating offset printing dampening water, and having a filter in the circulation flow path,
A printing press and a potential adsorption filter having a zeta potential adsorption action, which is different from the filter,
The filter has a melamine resin foam for filtering the fountain solution,
A dampening water circulation system comprising the filter on the upstream side of the potential adsorption filter when the circulation channel is viewed from the printing machine. The dampening water circulation system according to claim 7, wherein the filter includes a fiber molded body that holds the melamine resin foam. The dampening water circulation system according to claim 7 or 8, wherein the filter is formed by laminating a plurality of sheet-like melamine resin foams. The dampening water circulation system according to any one of claims 7 to 9, wherein the filter gravity filters the dampening water. A dampening water circulation method for circulating dampening water for offset printing,
A step of filtering said fountain solution by melamine resin foam,
Filtering the dampening water filtered with the melamine resin foam with a potential adsorption filter having a zeta potential adsorption action . A dampening water circulation method for circulating a dampening water for offset printing using a development-less PS plate,
A step of filtering said fountain solution by melamine resin foam,
Filtering the dampening water filtered with the melamine resin foam with a potential adsorption filter having a zeta potential adsorption action . A dampening water circulation method for circulating dampening water for offset printing,
Having a step of filtering the fountain solution with a melamine resin foam,
The said process is a circulation method of the dampening water performed using the filter provided with the said melamine resin foam and the molded object of the fiber holding the said melamine resin foam. The method of circulating dampening water according to claim 13, comprising a step of filtering the dampening water filtered with the melamine resin foam with a potential adsorption filter having an adsorption action of zeta potential.

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