JPH08252902A - Transfer method - Google Patents

Abstract

PURPOSE: To perform transfer so that color shift enters a tolerance range by using material quality of which the glass transition temp. is higher than the highest heating temp. at a time of treatment as a protective cover. CONSTITUTION: In a transfer method of a color art system wherein a temporary support 2 to which patterns 2 after exposure and development are bonded is passed through the nip between heat rollers along with a protective cover 1, as the material quality of the protective cover 1, aluminum, polyimide or polycarbonate being material quality of which the glass transition temp. is higher than the highest heating temp. at a time of treatment is used or material quality wherein a product of glass transition temp. and thickness is 20 ( deg.C.mm) or more is used. Even if the transfer passing the temporary support 2 through the nip between heat rollers along with the protective cover 1 is repeated any number of times, transfer wherein finish accuracy is good, that is, color shift is within a tolerance range can be performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image transfer method, and more particularly to a transfer method for producing a color proof by image transfer in a plate making process.

[0002]

2. Description of the Related Art When a printing plate using a plate-making material such as a PS plate is made from a color original and a large number of sheets are printed, the color original is usually printed with a four-color halftone negative or halftone positive using a color scanner. After making, after passing through the steps of pasting, returning, and lettering, one positive sheet of four colors is made, and proof printing is performed to confirm the finish before the actual printing. In this case, in the process of creating a screen negative or screen positive, the scanner disassembly check, the sticking etc. check in the one-sheet positive creation process, the print orderer confirmation in the proofing process, etc. Necessary for finishing, color proofs are made and checked for this purpose.

One of the methods for producing a color proof is to imagewise expose a photosensitive material as shown in FIG. 1 and temporarily support an image pattern (whether positive or negative) generated after development processing. The pattern 3 is attached to the body 2, and the pattern 3 is placed on the image receiving paper 4 on the aluminum plate 5 having a thickness of 0.5 mm and the upper surface is white-painted, and the protective cover 1 is placed on the temporary support 2. When pressure and heat are applied between the heat rollers, the entire pattern 3 is thermally transferred to the image receiving paper 4 to form a color proof. In this case, this pattern 3 after exposure and development is used to form yellow, magenta, cyan, and black (YMCK) color images using four photosensitive materials, and by sequentially transferring this to the same image receiving paper 4. , A multicolor image is formed. And all four color image receiving paper 4
Then, when the image receiving paper 4 is overlaid on the actual paper again and passed through the heat rollers again, the entire color pattern of the image receiving paper 4 is transferred to the paper. In this method, unlike the method in which an image is formed by exposing a photosensitive layer transferred onto a transfer paper to form an image, the formed images are sequentially color-coded by YM.
Since the CK is transferred four times in total, it is necessary to strictly perform the accuracy of the image transfer. However, the temporary support is slightly stretched by the first pressurization / heating of the heat roller, and further, the elongation is caused by the asymmetric deformation of each part due to the internal stress due to the influence of the pressurization / heating of the heat roller. Pressurization and heating of the heat roller after the second time is several tens to one hundred and several tens of μm.
It has slipped. This accuracy (color shift) is at most 100
Since it is desired to suppress the thickness to less than or equal to μm, preferably to about 50 μm, if it exceeds 100 μm, it is not very practical.

FIG. 2 is a diagram for explaining this state. In the conventional example, the protective cover 1 is made of a PET material having a thickness of 100 μm. Now, on the upper surface of PET, pulling force A1, A2 by the heat roller under high temperature of 100 ° C.
, The PET has a glass transition point of 70.
Since it is as low as ° C and therefore has no strength at high temperatures, its force is almost transmitted to the temporary support 2 below it, and large tensile forces B1 and B2 act on the upper surface of the temporary support 2. Due to the large pulling forces B1 and B2, the temporary support 2 expands and is distorted, which causes a deviation in the second transfer. The thickness of PET is 0.1 mm.
The material of No. 1 was 60 to 160 μm, which greatly deviated from the allowable range. Therefore, the thickness of PET is doubled to 0.2 m
The result was 50-130 when I changed it to the material of m
It was not so different from μm.

[0005]

SUMMARY OF THE INVENTION The object of the present invention is to obtain a good finish accuracy (i.e., color) regardless of how many times the temporary support to which the pattern 3 after exposure and development is attached passes together with the protective cover 1 between the heat rollers. The transfer is within a permissible range.

[0006]

In order to solve the above problems, according to the present invention, there is provided a transfer method of a color art system in which a temporary support having a pattern after exposure and development passes between a heat roller together with a protective cover. At this time, as the protective cover, a material having a glass transition temperature higher than the maximum heating temperature at the time of processing is used. Similarly, in the transfer method of the color art system, the product of the glass transition temperature and the thickness is 20 (° C · m) as a protective cover.
m) The above materials are used.

[0007]

As a result of the above, even if the temporary support on which the pattern after exposure and development is adhered together with the protective cover is repeatedly transferred between the heat rollers, the stress strain from the heat roller is applied to the temporary support. Since this protective cover acts to prevent the transmission, it is possible to perform the transfer with high finish accuracy (that is, the color misregistration is within the allowable range).

[0008]

EXAMPLES The present invention focuses on the fact that conventional PET does not have strength at high temperatures because it has a low glass transition point.
An experiment was performed by selecting a material having a high glass transition point as the material of the protective cover 1. Since the roller temperature was 130 to 140 ° C., the working temperature at the time of working the heat roller was 14
It is estimated to be slightly below 0 ° C. Therefore, the protective cover of the transfer method has a glass transition point of 140 ° C. or higher, that is, aluminum having no glass transition point, polyimide having a glass transition point of 250 ° C., and glass transition point of 15 ° C.
Three materials of 0 ° C polycarbonate have been found to be suitable. The table below shows the experimental results, such as changing the thickness of these materials.

As can be seen from this table, when the protective cover 1 is made of aluminum having a thickness of 0.2 mm, the finish precision is the best and is within 0 to 20 μm. Further, in the case of polyimide, the finish accuracy was 10 to 60 μm when using a polyimide having a thickness of 0.2 mm, and 10 to 50 μm when using a polyimide having a thickness of 0.4 mm. Further, in the case of polycarbonate, when the one having a thickness of 0.2 mm was used, the finishing accuracy was 30 to 80 μm, and the one having a thickness of 0.4 mm was 20 to 70 μm. From the above, it can be seen that there are 3 of aluminum, polyimide, and polycarbonate.
This means that both materials are suitable for the protective cover 1 because they cover the finishing accuracy of about 100 μm.

FIG. 5 is a graph of the table. The product of the glass transition point and the thickness is plotted on the horizontal axis, and the finishing accuracy is plotted on the vertical axis. The test is repeated multiple times and the upper limit is plotted with □ and the lower limit is plotted with Δ. It can be seen from the figure that if the glass transition point is low, the accuracy becomes poor even if the thickness is increased, and if the glass transition point is too high, the accuracy becomes poor if the thickness is too thin. Therefore, the accuracy is 100 μm
In order to suppress it below, the product of the glass transition point and the thickness needs to be 20 or more. Therefore, it can be understood that the protective cover 1 can be made of a material having a product of the glass transition point and the thickness of 20 or more.

FIG. 3 shows a temporary support 2 when the material of the present invention having a thickness of 100 μm is used as the protective cover 1.
It is a figure explaining the magnitude of the pulling force added above. As in FIG. 2, when the pulling forces A1 and A2 by the heat roller at a high temperature of 140 ° C. act on the upper surface of the protective cover 1 made of the material of the present invention in the direction of the arrow, the protective cover 1 has a glass transition point. Since it is as high as 150 ° C or higher and therefore has strength at high temperatures, most of the force applied there is carried by this protective cover 1, and the tensile forces B1 and B2 acting on the temporary support 2 below are compared with those in FIG. Will be considerably smaller. Therefore, since the pulling forces B1 and B2 are small, it is possible to perform the transfer with high finishing accuracy.

FIG. 4 shows a material according to the present invention having a thickness of 200.
It is a figure explaining the magnitude | size of the pulling force added on the temporary support body 2 when the thing of (mu) m and twice is used as the protective cover 1. Similar to FIGS. 2 and 3, when the pulling forces A1 and A2 at high temperature act on the upper surface of the protective cover 1 made of the material of the present invention in the direction of the arrow, the protective cover 1 has a glass transition point of 150 ° C. or more. Since it has high strength at high temperature and is twice as thick as the material of FIG. 3, this protective cover 1 bears most of the force applied there and acts on the temporary support 2 below. The tensile forces B1 and B2 are even smaller than in FIG. Therefore, it is possible to perform transfer with higher finishing accuracy than that of FIG.

[0013]

As described above, according to the present invention,
Since the protective cover is made of a material having a glass transition temperature higher than the maximum heating temperature at the time of treatment, or a material having a product of the glass transition temperature and a thickness of 20 (° C · mm) or more,
This protective cover prevents the stress strain from the heat roller from being transmitted to the temporary support, no matter how many times the temporary support with the exposed and developed pattern is transferred between the heat rollers together with the protective cover. Since it works, the finish accuracy is good and it is possible to keep the color shift within the allowable range.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a transfer method used in the present invention.

FIG. 2 is a diagram illustrating a pulling force under a protective cover of a conventional example.

FIG. 3 is a diagram illustrating a pulling force under a protective cover of the present invention.

FIG. 4 is a diagram illustrating a pulling force under a protective cover having a double thickness.

FIG. 5 is a diagram of finish accuracy with respect to a product of a glass transition point and a thickness.

[Explanation of symbols]

 1 Protective Cover 2 Temporary Support 3 Image Pattern (Positive or Negative) 4 Image Receiving Paper 5 Aluminum Plate

Claims (5)

[Claims] 1. A transfer method of a color art system in which a temporary support having a pattern after exposure and development is passed between a heat roller together with a protective cover, and the glass transition temperature of the protective cover is higher than the maximum heating temperature during processing. A transfer method characterized by using high-quality materials. 2. A transfer method of a color art system in which a temporary support having a pattern after exposure and development is passed between a heat roller together with a protective cover, and the product of the glass transition temperature and the thickness of the protective cover is 20 ( ° C ・ m
m) A transfer method characterized by using the above materials. 3. The transfer method according to claim 1 or 2, wherein aluminum is used as the protective cover. 4. The transfer method according to claim 1 or 2, wherein polyimide is used as the protective cover. 5. The transfer method according to claim 1, wherein polycarbonate is used as the protective cover.