Introduction of iron sheet printing method

Iron sheet printing is a method of printing on a metal plate, printing graphics and text on materials such as tin-plated iron sheets or aluminum sheets.

The printing method of iron sheet printing adopts offset printing, and the structure of plate making and printing machine is basically the same as that of ordinary printing paper. Since the printed metal plate cannot be bent like paper and stick to the impression cylinder, the metal plate can only pass horizontally between the blanket cylinder and the impression cylinder, so the arrangement and output of the three cylinders in the printing part Some parts are different from ordinary offset printing.

Due to the characteristics of metal raw materials, iron sheet printing has a variety of coatings.

Before printing, the metal sheet is cleaned and then printed by offset printing. First, print a layer of primer varnish ④, the second layer of white primer ③, then print the graphic ② in turn, and finally print the varnish ①. Because metal does not have absorption properties, it must be baked and dried once after each color is printed. Therefore, a drying device is installed on the printing machine. The purpose of baking is to speed up the drying speed of the oxidized conjunctiva of the volatile ink, so that it will not affect the overprinting work of the next color.

The drying method can use steam, infrared rays, electric heating, etc. The oven is long, and the printed product is dry when it enters from one end and comes out from the other end. The temperature of the oven is between 150 and 2000 °C. When printing the bottom varnish, the temperature needs to be 200 °C. The oven temperature should be around 150°C during color registration and varnishing.

Metal printing is very easy to wear the printing plate, so indirect printing is used, and the printing is transferred through the blanket, so that the contact form is hard, soft and hard, so as to meet the ink transfer performance of printing.

The ink for iron sheet printing has special requirements. Since the substrate is metal, the ink is difficult to fix on the metal surface, so the ink should meet the following requirements: heat resistance, after baking at 150 ℃, the color of the ink should still be very bright, and the color ink should be very bright. Not dim, white and not yellow; fastness, that is, strong adhesion, printed graphics and text will not fall off by mechanical stamping during can making; pressure water vapor resistance, after the canned food is sterilized and sterilized, the ink layer can withstand water Under the influence of steam, it does not change and does not expand; it is resistant to solvent erosion, light resistance, weather resistance, etc., and can withstand sunlight and various climates without discoloration or slight discoloration.

Tin printing is often used in the manufacture of candy and biscuit boxes, food cans, stationery boxes, beer cans, children's toys, and beautiful decorations.