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(11) | EP 1 214 987 A2 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Method and apparatus for producing planographic printing plate precursors |
| (57) A method and an apparatus for producing planographic printing plate precursors. In
a production line for planographic printing plate precursors, a first applying device
(14), a first drying device (22), a second applying device (16), a second drying device
(24), a third applying device (18) and a third drying device (26) are sequentially
disposed along a direction of an aluminum web (12), which is a support for the planographic
printing plate precursors, is conveyed. Curl of the aluminum web (12) is adjusted
by each of the applying devices (14,16,18). Since the curl adjustment for the aluminum
web (12) is conducted simultaneously with or before applying a photosensitive material
onto the aluminum web, the coating film is not damaged and fogging is not caused. |
BACKGROUND OF THE INVENTION
Field of the Invention
[0001] The present invention relates to a method and an apparatus for producing planographic printing plate precursors.
Description of the Related Art
[0002] In recent plate producing methods including electrophotographic plate producing methods, planographic printing plate precursors such as photosensitive printing plates and heat-sensitive printing plates have been widely used to facilitate automation of the producing process. Planographic printing plate precursors are generally produced in the following manner. Surface treatments, for example, graining, anodizing, and silicate treatments and other chemical conversion treatments are applied either singly or in an appropriate combination to the surface of a sheet-shaped or coil-shaped aluminum plate support. Then, after a photosensitive or heat-sensitive layer coating (hereinafter, referred to as a "coating film") is applied and dried, the planographic printing plate precursor is cut to a desired size.
[0003] The planographic printing plate precursors are subjected to processes such as exposure, development and gum coating, then set in a printer, and inked. By doing this, words and images can be printed on paper.
[0004] Fig. 4 shows a planographic printing plate precursor producing apparatus 112 for producing planographic printing plate precursors. This apparatus is disclosed in Japanese Patent Application Laid-Open (JP-A) No. 2000-51757.
[0005] In the planographic printing plate precursor producing apparatus 112, a web-shaped metal plate 114 wound in a coil is fed out by a feeding device 116, and conveyed by plural pass rollers 118. Then, an application solution is applied onto the web-shaped metal plate 114 by an applying device 120, and excess application solution is scraped from the web-shaped metal plate 114 by a scraping device 122.
[0006] In this planographic printing plate precursor producing apparatus 112, the applying device 120 or the scraping device 122 may curl the web-shaped metal plate 114, and there may even be curling in the finished planographic printing plate precursors. Therefore, after the application solution has been applied by the applying device 120 or after the excess application solution has been scraped by the scraping device 122, the curl of the web-shaped metal plate 114 is adjusted by a curl adjusting device.
[0007] Generally, the curl adjusting device contacts the web-shaped metal plate 114 to adjust the curl thereof. Accordingly, when the curl of the web-shaped metal plate 114 on which the application solution has been applied is adjusted by the curl adjusting device, there is a risk that a photosensitive layer (or a heat-sensitive layer) will be damaged or so-called fogging (a phenomenon in which pressure causes the photosensitive layer to deteriorate) will be caused.
SUMMARY OF THE INVENTION
[0008] In view of the above facts, an object of the present invention is to obtain a method and an apparatus for producing planographic printing plate precursors, wherein the curl of the support can be adjusted without damaging the coating film and without causing fogging.
[0009] In accordance with a first aspect of the present invention, a method for producing planographic printing plate precursors includes the steps of: applying an application solution onto a support; and adjusting an amount of curling of the support before the step of applying an application solution, in accordance with an expected amount of curling which is likely to be caused by the step of applying an application solution, such that a planographic printing plate precursor which is ultimately produced has a desired amount of curling.
[0010] In the method for producing the planographic printing plate precursors of the present invention, in the step of applying an application solution (hereinafter referred to as "applying step"), the application solution is applied to form a coating film (for example, a photosensitive layer or a heat-sensitive layer). However, before the applying step, in the step of adjusting an amount of curling (hereinafter referred to as "curl adjusting step"), the support is adjusted a predetermined amount in accordance with an expected amount of curling which is likely to be caused by the applying step. By so doing, the planographic printing plate precursor which is ultimately produced has a desired amount of curling.
[0011] Since the curl adjusting step is conducted prior to the applying step, the coating film which is formed by the applying step is not damaged. Even if the coating film is a photosensitive layer or a heat-sensitive layer, so-called fogging is not caused. As a result, the planographic printing plate precursors produced using this method have the desired curl, and problems or disadvantages in the quality of the coating films do not occur.
[0012] In accordance with a second aspect of the present invention, an apparatus for producing planographic printing plate precursors includes: an applying device, which applies an application solution onto a support; and a curl adjusting device, which adjusts an amount of curling of the support before the application solution is applied by the applying device, in accordance with an expected amount of curling which is likely to be caused by the applying device, such that a planographic printing plate precursor which is ultimately produced has a desired amount of curling.
[0013] Preferably, the applying device and the curl adjusting device are integrated as a meter bar coating device which brings a bar for application into contact with the support to apply the application solution.
[0014] More preferably, the meter bar coating device can adjust a wrap angle of the support with respect to the bar for application.
[0015] Still more preferably, the meter bar coating device can selectively apply one of a lubricant which reduces friction between the bar for application and the support and the application solution.
[0016] In the apparatus for producing the planographic printing plate precursors of the present invention, the application solution is applied by the applying device to form a coating film (for example, a photosensitive layer or a heat-sensitive layer). However, before the application by the applying device, the support is adjusted a predetermined amount by the curl adjusting device in accordance with an expected amount of curling which is likely to be caused by the applying device. By so doing, the planographic printing plate precursor which is ultimately produced has a desired amount of curling.
[0017] Since the curl of the support is adjusted by the curl adjusting device before the application solution is applied onto the support by the applying device, the coating film which is formed by the applying device is not damaged. Even if the coating film is a photosensitive layer or a heat-sensitive layer, so-called fogging is not caused. As a result, the planographic printing plate precursors produced by this apparatus have the desired curl, and problems or disadvantages in the quality of the coating films do not occur.
[0018] By using a meter bar coating device, it becomes possible to apply the application solution onto the support and to adjust the curl of the support both simultaneously and with a single device. Accordingly, the planographic printing plate precursor producing apparatus of the present invention has a simpler structure as compared with a case in which the applying device and the curl adjusting device are provided as separate units.
[0019] Further, the curl of the support can be easily adjusted merely by adjusting the wrap angle of the support with respect to the bar for application.
[0020] There are planographic printing plate precursors for which the coating film is formed on both surfaces (double-side coated plates) and those for which the coating film is formed on only one of the surfaces (single-side coated plates). In the planographic printing plate precursor producing apparatus of the present invention, when single-side coated plates are produced, a lubricant can be applied onto the surface on which the coating film is not to be formed. Accordingly, friction between the bar for application and the support is reduced, and wear to the bar for application can be prevented.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021]
Fig. 1 is a schematic structural view showing a planographic printing plate precursor producing apparatus according to an embodiment of the present invention.
Fig. 2A shows an applying device structuring the planographic printing plate precursor producing apparatus according to the embodiment of the present invention in a raised state.
Fig. 2B shows the applying device structuring the planographic printing plate precursor producing apparatus according to the embodiment of the present invention in a lowered state.
Fig. 3 is an explanatory view for explaining a wrap angle in the planographic printing plate precursor producing apparatus according to the embodiment of the present invention.
Fig. 4 is a schematic structural view showing a conventional planographic printing plate precursor producing apparatus.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0022] Fig. 1 shows a production line 10 of an embodiment of the present invention. This production line 10 is used to produce planographic printing plate precursors. In the production line 10, while an aluminum web 12 which is a support for a planographic printing plate precursor is being conveyed by a plurality of conveying rollers 48, a desired photosensitive solution is applied onto the aluminum web 12 to form a photosensitive layer thereon.
[0023] An unillustrated feeding device is disposed at a most upstream of the production line 10 (at a lower-left side in Fig. 1). The aluminum web 12 having, for example, a thickness of 0.1 to 0.5 mm is wound into a roll-shape to form an aluminum coil. The aluminum coil is then loaded into the feeding device. The feeding device feeds the aluminum web 12 toward a downstream side at a conveying speed which corresponds to a conveying speed of the entire production line 10.
[0024] The aluminum plate, which is a material of the support for the planographic printing plate precursor, may use, for example, pure aluminum such as A1050, A1100 or A1070 based on the Japanese Industrial Standard (JIS), or aluminum alloys such as Al-Mg alloy, Al-Mn alloy, Al-Mn-Mg alloy, Al-Zn-Mg alloy and Al-Mg-Si alloy. An ingot of aluminum conforming to the above standard is produced by a manufacturer by a process for producing aluminum plate. Then, the aluminum ingot is hot-rolled, heat-treated (annealed) as needed, and cold-rolled so as to form a web-shaped aluminum plate having a predetermined thickness. Finally, the aluminum plate is wound into a roll shape to form the aluminum coil.
[0025] The production line 10 is provided with a correcting device (a roller leveler, a tension leveler, or the like) for improving flatness of the aluminum web 12, an upper surface polishing device and a lower surface polishing device for polishing an upper surface and a lower surface of the aluminum web 12, a surface roughening device for roughening a surface of the aluminum web 12, an anodizing device for providing a known anodizing process for the aluminum web 12, and the like. The aluminum web 12 is subjected to required pretreatments by these devices.
[0026] At the downstream side of the anodizing device, as shown in Fig. 1, a first applying device 14, a first drying device 22, a second applying device 16, a second drying device 24, a third applying device 18 and a third drying device 26 are sequentially disposed along a direction the aluminum web 12 is conveyed (a direction of arrow F). The applying devices apply a desired application solution onto the aluminum web 12, and the drying devices dry the application solution applied onto the aluminum web 12. The first applying device 14, the second applying device 16 and the third applying device 18 have substantially the same structure. Therefore, in Figs. 2A and 2B, the applying devices 14, 16 and 18 are shown integrated and described as an applying device 20.
[0027] The applying device 20 has a bearing member 28, and a rod 30 which is supported by the bearing member 28 so that the rod 30 can rotate and contact the aluminum web 12. An inlet side damming member 32 and an outlet side damming member 34 are provided adjacent to the bearing member 28. An application solution storing portion 36 is formed between these damming members 32 and 34. An application solution 38 supplied from the application solution storing portion 36 contacts the aluminum web 12 to form a puddle 40. When the rod 30 rotates, the application solution 38 in the puddle 40 is scraped up and transferred onto the aluminum web 12.
[0028] The applying device 20 (the first applying device 14, the second applying device 16 and the third applying device 18) is raised and lowered by an unillustrated lifting device. When the application solution 38 is being applied to the aluminum web 12, the applying device 20 is raised by the lifting device so that the rod 30 contacts the aluminum web 12, as shown in Fig. 2A. When the application solution 38 is not being applied to the aluminum web 12, the applying device 20 is lowered by the lifting device so that the rod 30 separates from the aluminum web 12, as shown in Fig. 2B. Accordingly, the application solution 38 can be applied to the aluminum web 12 only when it is required.
[0029] As shown in Fig. 3, support rolls 42 and 44 are provided on upstream and downstream sides respectively in the conveying direction for each of the first applying device 14, the second applying device 16 and the third applying device 18. The support rolls 42 and 44 are rotatably provided so that a center of rotation does not move. When the applying device 20 has been raised, the support rolls 42 and 44 operate so that the aluminum web 12 contacts the rod 30 with a predetermined wrap angle θ. The wrap angle θ is defined by the degree to which the aluminum web 12 contacts the rod 30, the center of the rod 30 with being the apex of the wrap angle θ. The wrap angle θ is derived from the formula θ = 2α wherein α is an angle having P and Q as apexes and defined by the aluminum web 12 with respect to an imaginary line L that connects P and Q. P and Q are boundaries between the portions of the aluminum web 12 that contact the support rolls 42 and 44, respectively, and the portion of the aluminum web 12 that does not contact the support rolls 42 and 44 and that is disposed between the support rolls 42 and 44.
[0030] In this manner, when the aluminum web 12 is wrapped over the rod 30 with a predetermined wrap angle θ, a predetermined tension is applied to the aluminum web 12, and the curl of the aluminum web 12 is thereby adjusted. The wrap angle θ can be changed by adjusting an amount of raising the applying device 20 when wrapping the aluminum web 12 over the rod 30. Therefore, the tension applied to the aluminum web 12 is changed in correspondence with the magnitude of the wrap angle θ, and the curl adjustment for the aluminum web 12 can also be changed.
[0031] Within the applying device 20, the path along which the aluminum web 12 is conveyed, as well as positions of the first applying device 14, the second applying device 16 and the third applying device 18, are determined, so that the first applying device 14 applies the application solution onto a lower surface (surface B) of the aluminum web 12, and so that the second applying device 16 and the third applying device 18 apply the application solution onto an upper surface (surface A) of the aluminum web 12.
[0032] The first drying device 22, the second drying device 24 and the third drying device 26 are provided at the downstream sides of the first applying device 14, the second applying device 16 and the third applying device 18, respectively. Each drying devices 22, 24 and 26 are provided with a drying tank 46 along the direction the aluminum web 12 is conveyed. In order to dry the application solution applied to the aluminum web 12, hot air is fed from an unillustrated hot air feeder into the drying tanks 46. A temperature of the hot air, a length of the drying tank 46 in the direction of conveyance, and the like in each of the first drying device 22, the second drying device 24 and the third drying device 26 are set in accordance with drying conditions.
[0033] Next, a method for producing the planographic printing plate precursors by the planographic printing plate precursor producing apparatus 10 of the present embodiment, and an operation of the planographic printing plate precursor producing apparatus 10 will be described. A case of producing the planographic printing plate precursor in which only a front surface (surface A) has a photosensitive layer thereon (a single-side coated plate) will be described first. Then, a case of producing the planographic printing plate precursor in which both a front and a back surface (surfaces A and B) have the photosensitive layer thereon (a double-side coated plate) will be described.
[0034] When single-side coated plates are produced, a non-photosensitive lubricant (e.g., alcohol or water) which reduces friction between the aluminum web 12 and the rod 30 is selected as the application solution applied by the first applying device 14. A photosensitive material, for example, a photopolymer, which will eventually form the photosensitive layer is selected as the application solution, that is applied by the second applying device 16 and the third applying device 18.
[0035] When the first applying device 14 is raised by a predetermined amount, the rod 30 is brought into contact with the aluminum web 12 to a fixed wrap angle θ and the lubricant is applied to the back surface (surface B) of the aluminum web 12. The wrap angle θ is predetermined so that finished planographic printing plate precursors will have a desired curl, in consideration of curl caused to the aluminum web 12 by the second applying device 16 and third applying device 18. Depending on the situation, the wrap angle θ may be large. However, since the first applying device 14 brings the rod 30 into contact with the aluminum web 12 to curl the aluminum web 12 while applying the lubricant onto the aluminum web 12, friction between the aluminum web 12 and the rod 30 is reduced, and wear to the rod 30 is thereby prevented. Further, since the lubricant applied onto the aluminum web 12 is dried by the first drying device 22, the lubricant does not remain on the aluminum web 12 and does not affect quality of the finished planographic printing plate precursors. In other words, any material which reduces friction between the aluminum web 12 and the rod 30 and which does not affect the quality of the finished planographic printing plate precursors can be used as the lubricant. For example, a solvent including no solid matter, an aqueous solution of high molecular compound, an organic aqueous solution, a pigment dispersion solution, a colloidal solution or the like can be used.
[0036] Then, the second applying device 16 applies the application solution to the front surface (surface A) of the aluminum web 12, the second drying device 24 dries the applied application solution, the third applying device 18 applies the application solution to the front surface (surface A) of the aluminum web 12, and the third drying device 26 dries the applied application solution. As the application solution applied by the second applying device 16 and the third applying device 18, a photosensitive material such as a photopolymer, namely, a material which will eventually form the photosensitive layer, is selected. The wrap angle θ in the second applying device 16 and the third applying device 18 is also predetermined so that the finished aluminum web (planographic printing plate precursors) will have a desired curl. Further, the wrap angle θ may be large when the photosensitive material is being applied by the second applying device 16 and the third applying device 18. However, since the second applying device 16 and the third applying device 18 bring the rod 30 into contact with the aluminum web 12 to curl the aluminum web 12 while applying the photosensitive material onto the aluminum web 12, friction between the aluminum web 12 and the rod 30 is reduced, and wear to the rod 30 is thereby prevented.
[0037] In order to form the photosensitive layer on the front surface (surface A) of the aluminum web 12, the second applying device 16 and the third applying device 18 do not necessarily need to be both provided. Namely, even if only one of them is provided, it is possible to apply the photosensitive material to form the photosensitive layer. However, when the two applying devices are supplied as in this embodiment, the photosensitive layer having desired properties can be easily formed, for example, by sequentially applying different kinds of photosensitive materials.
[0038] After the photosensitive material has been applied onto the aluminum web 12, the aluminum web 12 is subjected to a required process, for example, an over-coated layer is formed on the photosensitive layer, and finally, the aluminum web 12 is cut into a predetermined size by a cutter to obtain the planographic printing plate precursors. The aluminum web 12 may also be temporarily wound into a roll shape, and set in a processing line before cutting, and then unwound to be cut.
[0039] Next, a case in which the double-side coated plates are produced will be described. In this case, the photosensitive material is selected as the application solution applied by the first applying device 14, in place of the lubricant selected when the single-side coated plates are produced. Afterwards, by subjecting the aluminum web 12 to the same process as that of the single-side coated plates, the planographic printing plate precursor in which the photosensitive layer is formed on both surfaces A and B can be produced. Further, when the photosensitive material is applied onto the back surface (surface B) of the aluminum web 12, two applying devices may be used so that a photosensitive layer having desired properties can be easily formed, in the same manner as on the front surface (surface A).
[0040] In this manner, in the planographic printing plate precursor producing apparatus 10 in this embodiment, the curl of the aluminum web 12 is adjusted by the first applying device 14 which exists before the second applying device 16 and the third applying device 18, so that the finished planographic printing plate precursors will have a desired curl, in consideration of curl caused to the aluminum web 12 by the second applying device 16 and the third applying device 18. In contrast to the conventional manner, because the curl of the aluminum web 12 is not adjusted after the photosensitive material has been applied, the formed photosensitive layer is not damaged and fogging is not caused. As a result, the finished planographic printing plate precursors have the desired curl, and problems or disadvantages in the quality of the photosensitive layers do not occur.
[0041] The number of the applying devices is not particularly limited. For example, the number of the applying devices may be increased so that the planographic printing plate precursor producing apparatus 10 can apply a larger curl to the planographic printing plate precursors.
[0042] In the present invention, in order to prevent fogging and damage to the formed coating film, the curl of the aluminum web 12 should be adjusted simultaneously with or before applying the photosensitive material. In the present embodiment, when single-side coated plates are produced, the curl adjustment by the first applying device 14 is conducted before applying the photosensitive material, and the curl adjustments by the second applying device 16 and the third applying device 18 are conducted simultaneously with applying the photosensitive material. When double-side coated plates are produced, the curl adjustments by the first applying device 14, the second applying device 16 and the third applying device 18 are all conducted simultaneously with the application of the photosensitive material. In a step even earlier than the curl adjusting performed by each of the applying devices, further curl adjusting devices can be separately provided. However, when a so-called meter bar coating device is used, as in the present embodiment, the application of the photosensitive material and the curl adjustment can be simultaneously conducted by a single device. This results in the planographic printing plate precursor producing apparatus 10 having a simple structure which is preferable. When the curl adjusting device is used, if it is intended not for the application of the photosensitive material but only for the curl adjustment, a specific structure thereof is not particularly limited.
[0043] The curl of the aluminum web 12 may be adjusted not only by changing the wrap angle θ in the first applying device 14 but also by adjusting the wrap angle θ in the second applying device 16 and/or the third applying device 18. Namely, which applying device to use for the curl adjustment can be suitably selected in consideration of a possible curl adjustment range in each applying device and a desired curl for the finished aluminum web 12. For example, when single-side coated plates are produced, if the curl adjustment from the back surface of the aluminum web 12 is not required, the first applying device 14 may be lowered to separate the rod 30 from the aluminum web 12.
[0044] Further, the curl of the aluminum web 12 can be easily adjusted by merely raising or lowering each applying device to change the wrap angle θ.
[0045] A specific value of the wrap angle θ is suitably determined depending upon the amount the curl should be adjusted in the each applying device. Preferably, the wrap angle θ is suitably changed within a range from 1° to 30° in correspondence with, for example, thickness of the aluminum web 12 and diameter of the rod 30. If the wrap angle θ is smaller than 1°, the contact state with the rod 30 which accompanies the aluminum web 12 being conveyed becomes unstable. As a result, there is a risk that the rod 30 cannot securely hold the aluminum web 12. On the other hand, if the wrap angle θ is larger than 30°, then even when there is lubricant or photosensitive material, friction between the rod 30 and the aluminum web 12 is increased because the contact area therebetween is increased, excessive resistance to the conveyance of the aluminum web 12 and to the rotation of the rod 30 is caused, and the amount the rod 30 wears becomes large.
[0046] The diameter of the rod 30 is preferably 3 mm to 50 mm, and more preferably 6 mm to 20 mm. In particular, in the planographic printing plate precursor producing apparatus 10 in this embodiment, since a radius of curvature for the aluminum web 12 at the wrap portion can be decreased by decreasing the diameter of the rod 30, sufficient curl of the aluminum web 12 can be obtained.
[0047] When the planographic printing plate precursors are produced by the method for producing the planographic printing plate precursors of the present invention, the planographic printing plate precursor producing apparatus 10 of the above embodiment need not necessarily be used. In short, it is fine so long as the curl adjustment is conducted before the application solution (photosensitive material) is applied. Therefore, the single applying device need not necessarily be able to conduct both the curl adjustment process and the application process. A structure in which the curl adjusting device and the applying device are completely separated from each other may also be used to conduct these processes.
[0048] In the above embodiment, only the case in which planographic printing plate precursors which use the photopolymer as the photosensitive material are produced has been described. However, the present invention can be widely used to produce planographic printing plate precursors on which photosensitive layers or heat-sensitive layers are formed. Specific examples of the planographic printing plate precursor include, for example, those having such photosensitive layers as described in the following (1) to (11):
(1) a photosensitive layer having an infrared absorbent, a compound which generates acid by heat, and a compound which crosslinks by acid;
(2) a photosensitive layer having an infrared absorbent, and a compound which becomes soluble in alkali by heat;
(3) a photosensitive layer including two layers: a layer having a compound which generates a radical by laser beam irradiation, a binder which is soluble in alkali, and a multifunctional monomer or prepolymer; and an oxygen blocking layer;
(4) a photosensitive layer including two layers: a physical development nuclei layer and a silver halide emulsion layer;
(5) a photosensitive layer including at least three layers: a polymerized layer having a multifunctional monomer and a multifunctional binder, a layer having silver halide and a reducing agent, and an oxygen blocking layer;
(6) a photosensitive layer including two layers: a layer having a novolak resin and naphthoquinone-diazide, and a layer having silver halide;
(7) a photosensitive layer having organic photoconductors;
(8) a photosensitive layer including two or three layers: a laser beam absorbing layer which is removed by laser beam irradiation, a lipophilic layer and/or a hydrophilic layer;
(9) a photosensitive layer having a compound which absorbs energy and generates acid, a high molecular compound which has, in a side chain, a functional group generating sulfonic acid or carboxylic acid by acid, and a compound which absorbs visible light to give energy to an acid generator;
(10) a photosensitive layer having a quinone-diazide compound and a novolak resin; and
(11) a photosensitive layer having a compound which is decomposed by light or ultraviolet radiation to form a structure crosslinking with itself or other molecules in the layer, and a binder which is soluble in alkali.
EXAMPLES
[0049] Next, the present invention will be further described in detail with the following Examples. However, the present invention is not limited to these Examples.
[0050] In these Examples, a surface of an aluminum plate was subjected to graining, etching, electrolytical roughening and anodizing processes, so as to prepare the aluminum web 12, which is a support. A photopolymer was then applied onto the aluminum web 12 by the planographic printing plate precursor producing apparatus 10 shown in Fig. 1, and the applied photopolymer was dried, so as to form a photosensitive layer. At this time, the first applying device 14 applied methanol onto a back surface (surface B) of the aluminum web 12. A conveying speed of the aluminum web 12 was 100 m/min, and an applying quantity of the photopolymer was 10 ml/m2 in the overall planographic printing plate precursor producing apparatus 10. A thickness of the aluminum web 12 and a diameter of the rod 30 were predetermined as shown in the following Examples, and curl of the aluminum web 12 was adjusted by changing a wrap angle θ in the first applying device 14. Finally, the aluminum web 12 was temporarily wound in a roll shape, unwound in a processing line, and cut by a cutter, so as to obtain planographic printing plate precursors (single-side coated plates) having a desired size.
[0051] The planographic printing plate precursors thus obtained were visually observed to evaluate flatness thereof. In the following tables, "A" denotes flatness with no problems, "B" denotes slightly damaged flatness which does not affect quality of the planographic printing plate precursors, "C" denotes damaged flatness which affects quality, and "D" denotes more damaged flatness which affects quality even more than "C". Further, "none" in the tables denotes a state in which the first applying device 14 has been lowered and the rod 30 is not in contact with the aluminum web 12.
Example 1
[0053] In Example 1, the thickness of the aluminum web 12 was 0.2 mm and the diameter of the rod 30 was 10 mm.
Table 1
| Wrap Angle θ | Flatness |
| None | D |
| 1° ≤ θ < 10° | C |
| 10° ≤ θ ≤ 15° | A |
| 15° < θ | C (inverted curl) |
[0054] From Table 1, it can be seen that the wrap angle θ was satisfactory if set to a range from 10° to 15° when the thickness of the aluminum web 12 was 0.2 mm and the diameter of the rod 30 was 10 mm.
Example 2
[0055] In Example 2, the thickness of the aluminum web 12 was 0.4 mm and the diameter of the rod 30 was 10 mm.
Table 2
| Wrap Angle θ | Flatness |
| None | C |
| 1° ≤ θ ≤ 10° | A |
| 10° < θ ≤ 20° | B |
| 20° < θ | C (inverted curl) |
[0056] From Table 2, it can be seen that the wrap angle θ was satisfactory if set to a range from 1° to 20° and preferably a range from 1° to 10° when the thickness of the aluminum web 12 was 0.4 mm and the diameter of the rod 30 was 10 mm.
Example 3
[0057] In Example 3, the thickness of the aluminum web 12 was 0.2 mm and the diameter of the rod 30 was 15 mm.
Table 3
| Wrap Angle θ | Flatness |
| None | D |
| 1° ≤ θ < 10° | C |
| 10° ≤ θ < 15° | B |
| 15° ≤ θ ≤ 30° | A |
| 30° < θ | C (inverted curl) |
1. A method for producing planographic printing plate precursors, the method comprising
the steps of:
applying an application solution onto a support; and
adjusting an amount of curling of the support before the step of applying an application solution, in accordance with an expected amount of curling which is likely to be caused by the step of applying an application solution, such that a planographic printing plate precursor which is ultimately produced has a desired amount of curling.
2. The method of claim 1, wherein the step of adjusting an amount of curling is conducted
at a surface of the support opposite to the surface onto which the application solution
is applied in the step of applying an application solution.
3. The method of claim 1, wherein the step of applying an application solution and the
step of adjusting an amount of curling are conducted substantially simultaneously.
4. An apparatus for producing planographic printing plate precursors, the apparatus comprising:
an applying device, which applies an application solution onto a support; and
a curl adjusting device, which adjusts an amount of curling of the support before the application solution is applied by the applying device, in accordance with an expected amount of curling which is likely to be caused by the applying device, such that a planographic printing plate precursor which is ultimately produced has a desired amount of curling.
5. The apparatus of claim 4, wherein the applying device is disposed at a side of the
support opposite to a side thereof at which the curl adjusting device is disposed.
6. The apparatus of claim 4, wherein the applying device and the curl adjusting device
are integrated as a meter bar coating device which brings a bar for application into
contact with the support to apply the application solution.
7. The apparatus of claim 6, wherein the meter bar coating device can adjust a wrap angle
of the support with respect to the bar for application.
8. The apparatus of claim 7, wherein the meter bar coating device moves vertically relative
to the support to adjust the wrap angle.
9. The apparatus of claim 7 or 8, wherein the wrap angle is adjusted within a range of
1° to 30°.
10. The apparatus of claims 6 to 8, wherein the meter bar coating device can selectively
apply one of a lubricant which reduces friction between the bar for application and
the support and the application solution.