JP2005125664A - Blanket for printing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a blanket in which a thickness unevenness can be reduced as compared with a prior art and a nip width can be adjusted by suppressing a pattern deviation width. <P>SOLUTION: The blanket 25 for printing includes a substrate layer 21 and an ink acceptance layer 24 provided on this substrate layer 21 in such a manner that a resin coating surface is formed on the ink acceptance layer 24, a relief is impressed to the resin coating surface to remove the resin of its press bonded part, and the remaining resin is transferred to a matter printed. The ink acceptance layer 24 is made of a silicone rubber or a silicone resin, a front surface of the ink acceptance layer 24 is mirror formed, and a rear surface of the substrate layer 21 is polished. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a printing blanket, and more particularly to a printing blanket used in an image forming method for obtaining a high-definition and flat image when forming a color filter for liquid crystal or printing other functional resins. .

  In the conventional general printing method, a lithographic, intaglio or relief printing plate is made according to the formed image, and ink is applied to the ink receiving portion (image line portion) of this printing plate with a roller or the like, and the surface of the rubber blanket and further the substrate. An image is formed by printing (transferring) thereon.

  By the way, in the prior art, when supplying ink onto a plate, it is performed through many rollers, and the ink is kneaded and transferred between the rollers. However, during this transition, the ink is torn between the two rollers. At this time, a stringing phenomenon occurs on the surface of the ink, and the thread breaks and adheres to each roller again. As a result, ink film thickness unevenness (melon pattern) occurs on the roller surface. This melon pattern also occurs when transferring from the plate surface to the blanket surface and from the bracket surface to the substrate, resulting in a decrease in the quality of the printed matter, that is, a decrease in resolution and flatness, and a feeling of roughness.

  Therefore, conventionally, a technique (Patent Document 1) has been proposed that aims to provide an image forming method capable of obtaining a high-quality printed matter that does not cause a stringing phenomenon and does not generate a melon pattern. . This patent document 1 has the following three main points.

1) An ink application surface is formed on a silicone blanket.
2) A relief printing plate having a non-image portion (a portion where no ink is applied) is pressed against the application surface to adhere to the projection portion, and the convex portion ink is removed from the base (silicone blanket) surface.
3) The ink remaining on the base (silicone blanket) surface is transferred to the surface of the printing body such as the base.

  However, in order to suppress unevenness in ink film thickness, increase resolution, and obtain image reproducibility, the required performance required for the blanket is high, and it is very difficult to obtain a blanket capable of obtaining high-quality printed matter. It was.

Moreover, the technique of the blanket which used the surface as the mirror surface is disclosed by patent document 1 and patent document 2 conventionally.
Patent Document 1 discloses a technique in which a liquid silicone rubber is self-leveled on a substrate and then cured to form a surface print layer. However, in the case of Patent Document 1, there is a limit in maintaining the levelness of the substrate itself, and there is a problem that it is difficult to keep the thickness accuracy of the blanket constant.

  Patent Document 2 discloses a technology in which a releasable mirror surface sheet is used, a material is injected into a mold and molded, and the sheet surface side is a mirror surface. However, in the case of Patent Document 2, there is a problem that the thickness of the blanket varies depending on the accuracy of the mold and the method of installing the mirror sheet. In any case of Patent Documents 1 and 2, only a liquid raw material can be used as the material of the ink receiving layer. Furthermore, in order to produce a large blanket (a size exceeding 1000 mm × 1000 mm), a large number of large molds, flat plates and the like are required, and there are limits to accuracy and cost.

  In general, the thickness accuracy is obtained by polishing the blanket surface (ink receiving layer surface), but for blankets that require a mirror ink receiving layer, the ink receiving layer is polished. I can't do it. For this reason, it has been very difficult to obtain thickness accuracy.

  Patent Document 3 describes a printing blanket structure in which a blanket comprising a base layer and a surface layer laminated on one side thereof, the opposite surface of the base layer being in a substantially non-woven processed state, and a substantially non-woven processed state Therefore, it is described that the outer surface of the woven fabric of the base layer is subjected to abrasion treatment and the base layer is covered with a synthetic resin or the like.

However, in the blanket structure described in Patent Document 3, the point where the warp and weft of the fabric on the back side of the blanket intersect with each other rubs the cylinder, and the metal peeling of the cylinder occurs. By covering the surface, the back surface is smoothed and the pressure applied to the blanket is distributed over the entire surface, which is different from the purpose of the present application. In addition, only the method described in Patent Document 3 cannot provide a blanket with a thickness variation as small as possible in order to form a high-definition image, which is an object of the present application.
JP 2003-136856 A (paragraph [0008] etc.) JP-A-8-112981 (paragraph [0007] etc.) JP-A-2-269095 (Claims etc.)

  The present invention has been made in consideration of such circumstances, and an object of the present invention is to provide a printing blanket that can reduce the thickness variation compared to the prior art and can adjust the nip width by suppressing the pattern deviation width. .

  The printing blanket according to the present invention comprises a base material layer and an ink receiving layer provided on the base material layer, a resin coated surface is formed on the ink receiving layer, and a relief is provided on the resin coated surface. In a printing blanket that presses to remove the resin at the crimped portion and transfers the remaining resin onto the substrate, the ink receiving layer is made of silicone rubber or silicone resin, and the surface of the ink receiving layer Is mirror-finished, and the back surface of the base material layer is polished.

  In this invention, it is preferable that the said base material layer consists of two or more layers, and the lowest layer is rubber | gum or its foam. In this case, the surface in contact with the lowest blanket cylinder is the back surface of the base material layer.

  According to the present invention, it is possible to provide a printing blanket that can reduce the thickness variation as compared with the prior art and can suppress the pattern deviation width and adjust the nip width.

  Hereinafter, the present invention will be described in more detail.

  As a result of various studies, the present inventors have found that the in-plane thickness accuracy of the blanket is 0.02 mm or less in order to suppress unevenness in the ink film thickness, increase the resolution, and obtain image reproducibility, and It came to investigate that the surface is a mirror surface. And the said thickness precision was able to be achieved by grind | polishing the blanket back surface instead of grind | polishing the blanket surface conventionally. That is, the gist of the present invention is that, as described above, the ink receiving layer is made of silicone rubber or silicone resin, the surface of the ink receiving layer is mirror-finished, and the back surface of the base material layer is polished. It is in.

  In the present invention, as the material used for the ink receiving layer, for example, any silicone rubber or silicone resin such as thermosetting type millable silicone rubber, addition type liquid silicone rubber, condensation type liquid silicone rubber, silicone resin or the like is used. be able to.

  The surface roughness Rz of the ink receiving layer is preferably 0.01 to 2 μm, more preferably 0.05 to 0.8 μm. If the surface roughness Rz is less than 0.01 μm, the contact area with the blanket substrate becomes too large, and the printed image cannot be printed strongly. On the other hand, if the surface roughness Rz is larger than 2.00 μm, the blanket surface shape is reproduced in the print pattern, and the shape of the edge portion is disturbed.

  In the present invention, as the base material layer, a resin film such as polyethylene terephthalate, polyimide, polyethylene, polypropylene, polycarbonate, a metal film such as stainless steel, a cloth made of various fibers, a nonwoven fabric, and a foam as a rubber or a compression layer Well-known materials composed of the respective layer composites can be used. The base material layer is mainly required to have a blanket elongation preventing function, and preferably includes a layer having compressibility. Moreover, it is desirable that the base material layer has two or more layers, and the lowermost layer is formed of rubber or a foam thereof among the materials.

  The thickness of the compressible layer is preferably 0.2 to 2.0 mm, more preferably 0.5 to 1.7 mm. Here, when the thickness is less than 0.2 mm, it does not perform the absorption function when the printing pressure is applied to the blanket, and the printing pressure is absorbed by the ink receiving layer, and the blanket surface apparently extends in the circumferential direction. As a result, the print pattern extends in the circumferential direction (displacement). On the other hand, if the thickness is greater than 2.0 mm, the amount of change in the lateral direction (in-plane direction) of the blanket increases during actual use, and the pattern shape tends to be misaligned.

  The hardness of the compressible layer included in the base material layer is preferably 20 to 80 ° (JISE). Here, if the hardness is less than 20 °, as in the case where the thickness of the compressible layer exceeds 2.0 mm, when the printing pressure is applied, the amount of change is large in the blanket plane direction, and the pattern shape shifts. cause. On the other hand, if the hardness exceeds 80 °, the same phenomenon as in the case where the thickness of the compressible layer is less than 0.2 mm is caused.

  In the base material layer, when a cloth or a non-woven fabric is used, depending on the type, the compressibility of the cloth or the non-woven fabric itself, the thickness of the cloth or the non-woven fabric due to the passage of time of use, etc. Therefore, it is not necessary to use cloth or nonwoven fabric for the base material layer.

  Next, a case where ink is transferred onto a glass substrate using the experimental machine shown in FIG. 4 will be described.

  Reference numeral 1 in the figure indicates a fixed frame. A coating unit 2, a platen plate 3, and a printing platen 4 are attached to the fixed frame 1, respectively. An uneven plate 5 made of glass is placed on the plate surface plate 3, and a glass substrate 5 is placed on the printing surface plate 4.

  A movable frame 7 is provided on the fixed frame 1. On the movable frame 7, a blanket cylinder 8 that rotates on the coating unit 2, the platen plate 3, and the printing platen 4 is attached. A blanket 9 for printing is wound around the blanket cylinder 8, and the wire bar 11 is half immersed in the ink 10 put in the coating unit 2.

  The movements of these experimental aircraft are as follows. First, the blanket cylinder 8 is stopped on the coating unit 2, and the wire bar 11 is brought into contact with the blanket 9 on the cylinder surface and rotated together to form an ink film on the blanket surface. Next, the blanket cylinder 8 is moved onto the platen plate 3 and is brought into contact with the concavo-convex plate 5 to roll, thereby removing the ink in contact with the tip of the convex portion from the blanket surface. Subsequently, the blanket cylinder 8 is moved onto the printing surface plate 4 and is brought into contact with the glass substrate 6 to roll, and the ink remaining on the blanket is transferred onto the glass substrate 6.

Next, a printing blanket according to an embodiment of the present invention and a printing blanket according to a comparative example will be described.
(Example 1)
FIG. 1 shows a cross-sectional view of a printing blanket according to Embodiment 1 of the present invention. The code | symbol 21 in a figure shows the base material layer of thickness 1.1mm. The base material layer 21 has a rubber sponge foam layer 22 of chloroprene rubber having a thickness of 1.0 mm and a JISE hardness of 52 ° as a lowermost layer, and a thickness of 0.1 mm formed on the rubber sponge foam layer 22. And a stainless steel film layer 23. An ink receiving layer (printing layer) 24 having a thickness of 0.6 mm is formed on the stainless steel film layer 23 of the base material layer 21. In such a printing blanket, the lowermost rubber sponge foam layer 22 is polished, and the surface of the ink receiving layer 24 is mirror-finished.

Next, a method for manufacturing the printing blanket 25 will be described.
First, one-component condensed liquid silicone rubber (trade name: TSE3941M, manufactured by GE Toshiba Silicone Co., Ltd.) was prepared. Further, a rubber sponge foam layer 22 of chloroprene rubber was pasted on the stainless film layer 23 in advance with an adhesive to prepare a base material layer 21. Next, the base material layer 21 was placed on a surface plate (not shown) with the stainless steel film 23 facing upward. Subsequently, after applying an adhesive on the stainless steel film 23 of the base material layer 21 in advance, the liquid silicone rubber composition is formed with a thickness of 0.6 mm by a knife coater, and is left to cure at 25 ° C. for 48 hours. I let you. As a result, the surface of the ink receiving layer 24 was mirror-finished. Further, after removing the base material layer 21 from the surface plate, the back surface of the rubber sponge foam layer 22 was polished to produce a printing blanket having a thickness of about 1.7 mm.

(Example 2)
FIG. 3 shows a cross-sectional view of a printing blanket according to Embodiment 2 of the present invention. The code | symbol 31 in a figure shows the base material layer of thickness 0.6mm. The base material layer 31 has a rubber sponge foam layer 32 of chloroprene rubber having a thickness of 0.5 mm as a lowermost layer and a JISE hardness of 68 °, and a thickness of 0.1 mm formed on the rubber sponge foam layer 32. And a stainless steel film layer 33. On the stainless steel film layer 33 of the base material layer 31, an ink receiving layer (printing layer) 34 having a thickness of 0.5 mm is formed. In such a printing blanket, the lowermost rubber sponge foam layer 32 is polished, and the surface of the ink receiving layer 34 is mirror-finished.

  Next, a method for manufacturing such a printing blanket 35 will be described with reference to FIG. In FIG. 2, reference numerals 41 a and 41 b indicate an upper mold and a lower mold constituting the blanket molding mold 41, respectively. A silicone rubber inlet 42 is provided on the side wall of the mold 41. First, the A / B agent of a two-component addition type silicone rubber (trade name: TSE3331, manufactured by Toshiba Silicone Co., Ltd.) as a main agent is mixed and stirred at a weight ratio of 1/1 to obtain a liquid silicone rubber composition. It was. Further, a base material layer 31 composed of a rubber sponge foam layer 32 and a stainless film layer 33 is disposed on the inner surface of the lower mold 41b of the molding die 41, and the surface is disposed on the inner surface of the upper mold 41a of the molding die 41. A smooth PET film 43 was set, and the gap (D) between the base material layer 31 and the PET film 43 was set to 0.5 mm (see FIG. 2).

  Next, the liquid silicone rubber composition is poured into the gap D from the injection port 42 of the molding die 41 and heated at 100 ° C. for 1 hour to crosslink the rubber composition to a thickness of 0.5 mm. Ink-receiving layer (printing layer) 34 was formed. Subsequently, after removing the laminated body in which the base material layer 31, the stainless film layer 33, the ink receiving layer 34, and the PET film 43 were sequentially laminated from the molding die 41, the surface PET film 43 was peeled off. Thereby, the surface of the ink receiving layer 34 was mirror-finished.

  Thereafter, the rubber sponge foam layer 32 on the back surface of the base material layer 31 is polished, the stainless steel film layer 33 is formed in the upper part, and the base material layer 31 in which the rubber sponge foam layer 32 is formed in the lower part (lowermost layer). Then, a printing blanket having a thickness of about 1.1 mm in which the ink receiving layer 34 was formed on the stainless steel film layer side of the base material layer 31 was produced.

(Comparative Example 1)
As compared with Example 1, except for the step of polishing the back surface of the blanket, the printing blanket obtained in the same manner as other steps was used as Comparative Example 1.

(Comparative Example 2)
Compared to Example 2, except for the step of polishing the back surface of the blanket, the printing blanket obtained in the same manner as other steps was used as Comparative Example 1.

(Comparative Example 3)
Compared with Example 1, the hardness of the foam layer of the base material layer was 15 °, the thickness was 1.2 mm, and the other steps were obtained in the same manner except for the step of polishing the back of the blanket. The printing blanket was referred to as Comparative Example 3.

(test)
Using each printing blanket manufactured as described above, a printing test was performed according to the method described above. The plate shape was a stripe pattern having a width of 20 μm, the print patterns actually printed on the glass substrate were compared, and the deviation of the shape was measured. Further, the set nip width between the plate and the blanket was set to 2 ± 0.2 mm, and it was confirmed whether or not a predetermined nip width could be obtained. Furthermore, regarding the manufactured blanket, the thickness of 25 points (5 points each in the vertical and horizontal directions) was measured in the plane, and the variation width was measured. The results are as shown in Table 1 below.

In Table 1, however, the in-plane thickness variation of the blanket was determined to be good if it was within 0.02 mm. Further, the pattern deviation width is allowed up to 3 μm. Further, it was determined whether the nip width could be adjusted so that the nip width was 2 ± 0.2 mm.

  According to the above embodiment, the surface of the ink receiving layer is mirror-finished, and the rubber sponge foam layer as the lowermost layer is polished. In addition, the nip width can be adjusted while suppressing the pattern deviation width. In addition, as a material for the ink receiving layer, either a liquid raw material or a solid raw material can be used.

  As described above, by making the surface of the ink-receiving layer of the blanket a mirror surface, it is possible to obtain a print pattern having a flat film thickness without disturbing the edge shape. Further, by forming the ink receiving layer with silicone rubber, 100% of the ink patterned on the blanket surface can be transferred to the printing medium. That is, the ink is not cracked in the transfer process from the blanket onto the substrate, and the stringing phenomenon does not occur. Accordingly, it is possible to form a very high-definition pattern, for example, a line having a width of 2 μm, by using the blanket of the present invention.

  Furthermore, by polishing the back surface of the base material layer of the blanket, the thickness variation in the blanket surface can be reduced, and a nip with high width accuracy can be obtained during printing. In combination with the above effects, it is possible to perform printing that can accurately reproduce a desired printing pattern.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

Sectional drawing of the blanket for printing which concerns on Example 1 of this invention. Explanatory drawing of the metal mold | die for manufacturing the blanket for offset printing which concerns on Example 2 of this invention. Sectional drawing of the printing blanket which concerns on Example 2 of this invention. Explanatory drawing in the case of transferring an ink on a glass substrate using an experimental machine.

Explanation of symbols

1 ... fixed frame, 2 ... coating unit, 3 ... platen,
4 ... Printing surface plate, 5 ... Uneven plate, 6 ... Glass substrate,
7 ... movable film, 8 ... blanket cylinder, 9 ... blanket cylinder,
10 ... Ink, 11 ... Wire bar, 21, 31 ... Base material layer,
22, 32 ... rubber sponge foam layer, 23, 33 ... stainless steel film layer,
24, 34 ... ink receiving layer (printing layer), 41 ... molding die, 41a ... upper die,
41b ... Lower mold, 42 ... Injection port, 43 ... PET film.

Claims (2)

Comprising a base material layer and an ink receiving layer provided on the base material layer, forming a resin coated surface on the ink receiving layer, pressing a letterpress on the resin coated surface, In a printing blanket that removes the resin and transfers the remaining resin onto the substrate,
The printing blanket, wherein the ink receiving layer is made of silicone rubber or silicone resin, the surface of the ink receiving layer is mirror-finished, and the back surface of the base material layer is polished.   The printing blanket according to claim 1, wherein the base material layer is composed of a plurality of layers, and the lowermost layer is rubber or a foam thereof.

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