JPS5850541A - Manufacture of printing plate of photosensitive resin relief printing - Google Patents

Abstract

PURPOSE:To obtain a printing plate of photosensitive resin relief printing, which is excellent in adherence strength of a scanning part, by executing irregular exposure through a contact screen, and forming a sharp angle part lower than height of the scanning part, and a hardening resin layer, on a nonscanning part. CONSTITUTION:In order to provide a planeness, a transparent and colorless glass 1 plate which is excellent in planeness is placed below, and a negative film 2 is placed so that the film surface becomes up. Subsequently, the film 2 and a photosensitive resin layer 4 are covered with a transparent film 3 so that both do not come into direct contact with each other, and also the photosensitive resin layer 4 is provided by coating so as to be superposed on it. Subsequently, the upper surface of the photosensitive resin layer 4 is covered, for instance, with a transparent film 5 to which a primer obtained by adding a sensitizing agent to a polyester film, as a base material of photosensitive resin relief printing. subsequently, from the lower side, main exposure is executed, and after that, from the upper side, irregular exposure is executed through a contact screen 6 and a glass plate 7. In this way, a scanning part 9, a sharp angle part 10' being lower than height of the scanning part 9, and a resin layer 12 are formed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is based on I! ! As shown in Fig. 1, a photosensitive resin with excellent dense layer strength in the 1-line portion is made by placing a negative chip 2 on a glass plate 1, overlaying a transparent cover film 3, and then applying a photosensitive resin layer 4 on the entire surface. A film 5, which will be a base material for a photosensitive resin letterpress, is coated on top of the contact screen, and a glass plate 7 is placed on top of the contact screen so that the film 5 and the film surface 8 of the contact screen 6 are in contact with each other. A step of performing a single exposure from the glass plate 7 side and a step of back exposure from the glass plate 7 side are carried out. Develop by washing off the hardened parts, etc.
Further, a uii+ line portion 9 as shown in FIG. 2 is formed, and a pointed corner portion 10 is formed in the non-printing portion. By adjusting the exposure precision of the back exposure, the sharp corner part 10 is formed to be lower than the image area 9, and the difference in height between the image area and the non-image area is small, so that even if Even if ink is supplied to non-print areas, ink does not accumulate easily, and even when printed, small dots are printed so they are not noticeable.
It plays the role of preventing keratin.

Conventional photosensitive resin letterpress printing as described above is a one-line part.

In particular, if excessive printing pressure is applied to a line part such as a fine point, thin line, or character, the line part will stretch in the direction along the base film, and when the printing pressure is removed, it will repeat the expansion and contraction, returning to its original state.
Printing more than 10,000 times is undesirable because it tends to peel off.

In order to eliminate such drawbacks of photosensitive resin letterpress printing, there is a method of increasing the adhesion strength between the base film and the image area by using a primer, etc., but this increases the number of steps and is complicated. If an attempt is made to improve the hardness of the ink to make it less likely to deform, there are drawbacks such as a decrease in ink adhesion.

The present inventor conducted research to improve writing performance in a single drawing area without making major changes to conventional materials and processes, and as a result, in addition to providing a sharp corner in the non-printing area as described above, By forming a cured resin layer that is lower than the height of the sharp edge, it strengthens the adhesion of the printed area to the base material and at the same time suppresses the deformation of the single line area when excessive printing pressure is applied. Based on this fact, we have completed the present invention.

The present invention will be explained in more detail below.

Each process of the present invention is the same as the conventional process except for the step of scattering exposure. First, in order to provide flatness, a transparent and colorless glass plate with excellent flatness, for example, 10 mm thick, is placed underneath. Then place a negative chip film with the necessary lines, letters, etc. or photographs shaded on it so that the film side (emulsion side) is facing up. 1. Next, add the sheep paste described in 11 and the photosensitive resin layer described below. It is usually covered with a transparent polypropylene film 5 about 20 mm thick to prevent direct contact.

Further, the photosensitive resin layer 1 is coated on top of the photosensitive resin layer 1. Known photosensitive resins include unsaturated polyester and acrylic monomer, polyamide copolymer, polyurethane and acrylic monomer, polyvinyl alcohol and acrylic monomer,
Monomers, oligomers or prepolymers such as alcohol-soluble polyamide and acrylic monomer, polyvinylpyrroli F7 and acrylic monomer, synthetic rubber and acrylic monomer can be used, and as a photopolymerization initiator hydroquinone, benzoin, anthraquinone, benzoin methyl ether, benzoin ethyl Ether or the like is used as a stabilizer, with the appropriate addition of P-phereamine, P-methoxyphenol, etc., and for example, the resin is held in a bucket and applied to a uniform thickness on the cover film using a squeegee. Preferably, the resin is applied to a thickness of 0.55 to α6xaK by placing the resin on the cover film and pressing it from above and below with a flat surface plate to obtain a uniform thickness.
I can do it. Next, on the photosensitive resin layer, a polyester film or the like coated with a primer made of JF polyester resin with a sensitizer added thereto is filled as a base material for a photosensitive resin relief plate.

There are two methods for scattering exposure through a contact screen: using a scattering light source and using a non-scattered light source.
Methods using a non-scattered light source include scattering the incident light using a diffuser sheet, or using the thickness of the base material of the contact screen to scatter the incident light. Any method may be used, but as a method that can reliably perform scattering exposure with high precision using an existing non-scattered light source, there are two methods: As shown in Figure 4, the film surface 8 of the contact screen is on the opposite side of the light source, and there is a difference between the contact screen and the photosensitive resin letterpress.
1 is preferable.

In the above, the necessary thickness of the base material of the contact screen to scatter incident light using the thickness of the base material is 100 to 200/a. Any embossed type may be used, and one with a thickness of 100 to 200 μm may be used.

The light source used for scattering exposure through the contact screen can be one that emits light of essentially the same wavelength as the light source at the front end, such as an ultra-high pressure mercury lamp, a lateral pressure mercury lamp, a low ratio mercury lamp, a carbon arc, a xenon arc, Metal halide lamps and other light sources can be used, and exposure wrinkles can be
Although it varies depending on other conditions, 0.5 to 1 of the main exposure
．． It can be adjusted as appropriate to the 5x gold standard.

By performing scattering exposure through the contact screen as described above, the light passing through the lowest optical density part of the contact screen hardens the photosensitive resin in the part directly below it that contacts the base material of the photosensitive resin letterpress. The light passing through other parts of the contact screen and the light scattered by the method described above are cured over the entire area of the photosensitive resin letterpress in contact with the substrate, and then developed.

As shown in FIG. 5, the icon part 9 and the part that is not exposed during the main exposure, that is, the non-image part, are provided with a pointed part 10' and a resin layer whose height is lower than the height of the line part according to the scattering exposure IK through the contact screen. form 12.

Although the above development differs depending on the photosensitive resin constituting the photosensitive resin relief printing plate, it can be carried out, for example, by washing and removing the uncured portions using a weak alkaline solution such as sodium borate, water, or the like.

The present invention has the above-mentioned configuration, and therefore, even under excessive printing pressure, deformation of the print area occurs not only in the single line area.

The deformation is absorbed because it extends to the cured resin layer formed in the non-image area, and even if excessive printing pressure is applied and removed repeatedly, the image area will peel off, especially fine points, thin lines, and fine lines. Not only can characters and other objects be prevented from peeling off and there is no problem with printing, but it is also possible to print with thinner or finer lines than before, and it is possible to use existing equipment and materials for each process. It has the advantage that it can be carried out without increasing the complexity of the process.

Examples that specifically illustrate the present invention are listed below.

Example: Place a negative film with a thickness of 100 μm on a glass plate with a thickness of 10 μm, cover the negative film with a holiflovirene cover film, and place an unsaturated polyester photosensitive film on the cover film. Apply the resin to a thickness of 0.55 IIm, and then apply the resin to a thickness of 100μm.
After applying a polyester-based brimer in advance, place the ester film so that the ester film is in contact with the resin, and then place a 200μ thick sheet of 8 lines on top of it so that the ester film is in contact with the resin.
Layer the 5-wire/1nch contact screens so that the film side is on the outside, and then use an ultra-high pressure mercury lamp to open the contact screen from the film side for about 30 seconds (approximately 69 (equivalent to JMJK)
Exposure to light, then use the same light from the opposite direction for about 50 seconds (equivalent to about 900 mJ) l! After the above exposure, the polyvarnish film was peeled off from the cover film together with the exposed resin, and cleaned with a 1-aqueous sodium borate solution.
After removing unused resin and drying.

J! In order to completely cure the resin, additional exposure was performed for about 50 seconds.

When the obtained printing plate was attached to a cylinder and printing was performed, the fine 11ill line portion did not peel off even after 500,000 times of printing.

A schematic sectional view, FIG. 2 is a schematic sectional view of a printing plate manufactured by the method shown in FIG. 1, FIG. 3, and #! 4 is a schematic sectional view showing an embodiment of the present invention, and FIG. 5 is a schematic cross-sectional view showing an embodiment of the present invention.
j, is a schematic cross-sectional view of a printing plate manufactured by the method shown in FIG. 4;

1...... Glass plate 2... Negatep 3... Transparent film 4... Photosensitive resin layer 5 ......Transparent film 6...Contact screen 7...
...Glass plate 9... Image area 10, 10'... Pointed corner part 11... Diffusion sheet 12.
・・・・・・・・・Hardened resin layer Fang 1 Fig. 2 Fig. 2 Fang 3 Fig. Fang 4 Fig. Fang δ

Claims (1)

[Claims] 0) Forming a sharp edge portion and a cured resin layer in the non-image area with a height lower than 46 mm in the image area by performing scattering exposure from the light-transmitting substrate side through a contact screen. A method for producing a printing plate for a photosensitive resin letterpress plate, characterized by the following. (2) fi Ranmen Hikari uses the narrow side of the contact screen as an advance method. (3) The scattering exposure is performed by placing a diffusion sheet between the light-transmitting substrate and the contact screen, and the film surface of the contact screen is covered with the diffusion sheet side.