JPH04369539A - Manufacture of screen printing plate - Google Patents

Abstract

PURPOSE:To manufacture a reusable screen printing plate by a simple process. CONSTITUTION:A sheet made of a shape memory polymer having ink permeable through-holes is pressed at temp. equal to or higher than the glass transition temp. of said polymer to close the through-holes and subsequently cooled to the glass transition temp. or lower to form a base plate. The printing image forming part of the base plate is heated to the glass transition temp. to return the shape memory polymer of the base plate to the shape before pressing to prepare a screen printing plate.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing screen printing plates.

0002

2. Description of the Related Art A conventional screen plate making process for screen printing is shown in FIGS. 6 and 7. First, a screen gauze 8 is stretched using a fabric such as silk or nylon as shown in FIG. 6 a and FIG. 7 a. Next, a photosensitive emulsion 9 is applied and dried to obtain an original plate as shown in FIG. 6b and FIG. 7b. Next, the positive film 10 is exposed as shown in FIG. 6C and FIG. 7C.

In FIG. 7C, the image area 11 is a portion through which no light passes, and is not exposed to light. Next, by immersing it in a developer, the unexposed areas are dissolved and removed, as shown in FIG. 7d. A plate for screen printing is made. When printing using this plate, place the printing paper under the screen and press the ink onto the screen.
Only the portion corresponding to the image area 11 passes the ink, and a printed image is obtained.

[0004] At this time, the wire diameter of the screen is 60
μm~500μm, screen line spacing is 130μm
m to about 1500 μm, and an appropriate value is selected depending on the precision of the image.

[0005]

[Problems to be Solved by the Invention] The conventional plate-making process described above has the following problems. (1) The plate cannot be used repeatedly and is disposable. (2) Since development is a chemical process, the plate-making process is complicated and time-consuming. An object of the present invention is to propose a method for manufacturing a screen printing plate that has a simple plate-making process and allows the plate to be reused.

[0006]

[Means for Solving the Problem] A screen gauze is made from a fabric made of shape memory polymer threads, and after being flattened by pressure at a temperature higher than the glass transition temperature, an original plate is made by cooling. Next, the printed image area of the original plate is heated again to a temperature higher than the glass transition temperature, so that only the printed image area returns to the net shape of the screen gauze.

[0007]

[Operation] When printing using the screen printing plate produced by the above-described method, the printing image area is reticulated and ink passes through it, and the other areas are flat and ink does not pass through, so that printing is performed in the image area.

[0008]

Embodiment An embodiment of the present invention will be described with reference to FIGS. 1 and 2. In the figure, 1 is a screen gauze woven with shape memory polymer threads 1a, 2 is a smooth pressure plate, 3 is a film-like original plate made of pressure-shaped shape memory polymer, and 4 is an image area.

[0009] Shape memory polymers have a glass transition temperature (T
g) If it is above, the polymer has the property of rapidly decreasing its elastic modulus and returning its shape to the memorized shape. One of its characteristics is that it can undergo larger plastic deformation strains than shape memory alloys. The process of the present invention for making a screen printing plate using a polymer having such properties is shown in FIGS. 1 and 2.

First, as shown in FIGS. 1A and 2A, a screen gauze 1 is made of shape memory polymer threads 1a. This is the original form of polymer memory. When the temperature reaches Tg or higher, the polymer thread 1a returns to the state shown in FIG. 2a. Next, as shown in FIG. 1 b and FIG.
multiply. Since the polymer is soft and easily deformed, the polymer thread 1a is plastically deformed and undergoes large plastic deformation between the pressure plates 2 to form a film shape. Next, in this state, cool
The temperature is made sufficiently lower than Tg. The polymer becomes hard, as shown in Figure 2c. A film-like original plate 3 is obtained. The original plate 3 does not allow ink to pass through, and serves as an original plate for screen printing.

Next, as a method of generating an image on the original plate, as shown in FIG. 2D, a hot ray is applied only to the image area 4, and the temperature of that area is raised to a temperature higher than Tg. Then, only the drawing area 4 returns to its original memory shape, and is shown as e in FIG.
You can make a version for screen printing like this. Methods of applying heat rays include methods such as using an infrared laser beam, or using a mask and applying infrared lamp light. If you want to change the image after printing is completed, such a plate can be heated to raise the temperature above Tg, as shown in Figure 2.
Since the state returns to state a, the same process can be performed again. In this way, the shape memory polymer plate can be used repeatedly. Furthermore, since it does not involve any chemical processes, it is easy to process.

[0012] When a polyurethane type polymer is used as the shape polymer, the glass transition temperature (Tg) is -30°C to +70°C.
It is freely configurable between ℃. As the screen gauze 1, as shown in FIG. 3, by inserting a steel wire 5 into the core of a thread 1a made of a shape memory polymer, image distortion during pressure shaping and image reproduction can be prevented. Also, Figure 4
As shown in FIG. 2, a mesh of steel cores 5 may be made and a shape memory polymer 6 may be attached around the mesh. FIG. 5 shows an example in which an original plate is made of a sponge-like shape memory polymer 7 having microscopic through-holes.

[0013]

[Effects of the Invention] In the method of manufacturing a screen printing plate according to the present invention, a shape memory polymer sheet having through holes through which ink can pass is pressed at a temperature higher than the glass transition temperature to close the through holes. Then, the same sheet is cooled to below the glass transition temperature to form an original plate, and then the printing image forming part of the original plate is heated to above the glass transition temperature to change the shape memory polymer of the original plate to the shape before pressurization. By restoring
It has the following effects. 1. We can provide screen printing plates that can be used repeatedly. 2. The original plate can be manufactured by pressure shaping, heating, etc., without any chemical processing.
Easy to process.

[Brief explanation of the drawing]

FIG. 1 is a flow diagram showing a plate-making process according to the present invention.

FIG. 2 is a flow diagram similar to FIG. 1 in a graphical representation.

FIG. 3 is a perspective view showing the structure of the screen gauze.

FIG. 4 is a perspective view showing the structure of another screen gauze.

FIG. 5 is a perspective view of an original made of a sponge-like sheet of shape memory polymer.

FIG. 6 is a flow diagram showing a conventional plate-making process.

FIG. 7 is a flow diagram similar to FIG. 6 in a graphical representation.

[Explanation of symbols]

1 Screen gauze 1a Shape memory polymer thread 3 Film-like original plate 4 Drawing area

Claims (1)

[Claims] Claim 1: A shape memory polymer sheet having through holes through which ink can pass is pressurized at a temperature above the glass transition temperature to close the through holes, and then the sheet is cooled below the glass transition temperature. A screen printing plate characterized in that the printing image forming part of the original plate is heated to a temperature higher than the glass transition temperature to restore the shape memory polymer of the original plate to the shape before pressurization. Production method.