Screen photosensitive plate and printing process (on)

First, photosensitive plate process flow:

Screen frame stretch - on the photosensitive plastic - on the photosensitive liquid - dry - light - pattern

Drawing Black and White Manuscript - Rinse Developer - Dryer - Reinforce - Inspection Repair - Proofreading

Screen box preparation:

(1) Screen frame materials and specifications: Screen frame materials are mainly high-quality wood (such as willow, pine), but also hard aluminum alloy or special-shaped steel pipe. Selection requirements are straight and light, cold, hot dry, temperature is not easy to bend, dry wood, wood grain integrity, no wood eyes, not easy to deformation, to reduce the deformation can be coated with tung oil or lacquer and so on. The size of the screen frame is determined by factors such as the width of the material to be printed and the size of the material to be scratched. Generally, the size of the screen frame is fixed, and the cross section of the frame material is strong and generally 40×30 mm.

(2) Screen size and selection: The screen requires strong and durable, the mesh size is the same, and the latitude and longitude lines are smooth and uniform in thickness and thickness. The screen's stretching deformation is small and can resist general chemical corrosion. At present, there are two kinds of silk and Jinnuan screen meshes, and the mesh square inch is about 200 inches.

2, mesh plate system

The metal mesh frame can be adhered to the frame, and the wood mesh frame can be adhered, or the stud method can be used. At present, the sticking method is mainly used. Adhesion method commonly used polyvinyl acetal (commonly known as all-purpose adhesive) as a sticking agent, it can be dissolved in anhydrous alcohol, acetone, ether and other organic solvents. When used, the adhesive is applied to the frame, and after drying, the taut screen is flatly adhered to the coated frame, and then the organic solvent is brushed to dissolve the polyvinylalcohol glue and adhere to the screen. Together, when applying the adhesive, apply a layer of polyvinyl acetal to the clean and smooth frame of the plastic mesh on one side and the outside of the mesh. The new mesh frame is usually applied 2-3 times, and the old frame is coated with 1- 2 times, after being painted and placed for 24 hours, the inserting nail method is to place the cut screen on the square groove of the wooden frame, and then use 5 points of nails to fix the length direction of the nail. The screen swells on the other side, and one side of the screen is nailed tightly, typically one nail per centimeter, and the width is the same as the length.

Second, the description of the black and white manuscript

Drawing a black and white draft Cover a transparent substrate or clear glass over the artwork. With a pen or other tools for drawing, the drawing sunscreen is generally used for drawing ink. When drawing, the lines must be uniform in thickness and smooth, and the pattern surface should be clear. The portrayal should not be light traced and must be lightened, checked and checked to prevent leakage of flowers and flowers. When black and white rare stains, impurities, or multiple flowers are found, apply a sculpting knife to trace dry and use a row of pens. The black and white manuscript is coated with a layer of varnish to prevent the glue from being blurred when the glue meets water or rubs against each other.

Third, photolithography

Photolithography is the use of photographic methods to transfer the pattern to the process of reaffirming the screen, the sensitization is to cover the black and white manuscript coated with sensitized adhesive on the Internet, the above light to expose, the light through the place and the sensitization, hardening, light penetration In the place (lines on the black-and-white draft), the photosensitive adhesive changes and can be washed out to reveal the mesh.

1, photosensitive adhesive, photosensitive liquid preparation

(1) Preparation of Photosensitive Adhesive: Add 100 g of polyvinyl alcohol to 500 g of water and then heat in a compartment of 80-90 degrees for 2-4 hours to form a transparent paste and cool it for use.

(2) Preparation of photosensitive solution: In a dark room, 1 g of ammonium dichromate and 5 g of water are dissolved by shaking, and 20 ml of alcohol is added to make it evenly mixed.

2. Photosensitive adhesive: Use a metal spatula to evenly coat the photosensitive liquid with a brush on the screen to make it uniform, without bubbles, and then dry or dry it.

(1) On the photosensitive liquid: In the dark room, the photosensitive liquid is evenly coated with a brush on a screen coated with a photosensitive resin, dried or dried with a fan, and the drying time is 1-2 hours. The maximum length must not exceed 4 hours, promptly light after drying. Note: Dark interior lighting. If no darkroom can be performed at night. Do not encounter light.

(2) Sensitization: After the photosensitive liquid has been dried and it has been dried, it can be sensitized on a smooth tabletop. The light source uses four 40-watt fluorescent lamps, and two 200-watt electric lamps can also be placed on the screen side. 30-40 cm inflow. Before turning on the light, place the black and white paper on the screen so that the glue surface of the screen is connected to the ink surface of the black and white draft. There must be no gap between the desktop, the screen, and the black and white draft. For example, the black and white draft is soft. Film can be placed on the top of the appropriate glass, black and white after the release of a good light can be light and time, when the light can be placed in the pattern of a small piece of shade, can pick up at any time to check the photosensitive and photosensitive Changes in the color of the glue, when it is found that the contrast is greatest, the light should be stopped and the light source turned off.

(3) Development: Immediately after photosensitization, the pattern is washed with 60-80°C hot water, and the film in the grain is peeled off and then rinsed with cold water. When washing, it should not be touched, and then be dyed with a direct dye. The coloring instructions are not flushed and should continue to be washed. If there is unclear degumming, blocked mesh, etc., 25% ammonia can be used to lightly brush on the front and back of the screen, and then washed with water. Finally, the screen will be placed in a ventilated place or fan. dry.

(4) Inspection and repair: Pick up the screen for inspection. If it is found that the sand hole or the sealed place can be partially re-treated, but it does not need to be developed.

(5) Paint reinforcement: In order to enhance the durability of the photoconductive film, after development and drying, it shall be reinforced with lacquer, and the flowers or trachoma shall be painted with lacquer. If the pattern is not clear or the mesh is blocked, the needle can be used. Paint on the outside of the Internet version first, and then wipe the lacquer on the other side with paper to make the pattern clear, and place it in the temperature-temperature room for 24 hours, and then paint on the other side after drying. The method is the same as the other side. And at the border of the screen frame and the wooden frame with a fine cloth or stencil net, etc. for edge sealing to enhance the fastness.