Indian Railway is in tinplate (tin plate) on the printed pattern. Is the use of water, the physical properties of ink repulsion, by means of printing pressure to the printing blanket is transferred to the graphic tinplate, below the principle of offset printing. The process for ink has special requirements.
Printing works:
Tinplate printing is the use of water, the physical properties of the ink repulsion, with the printing pressure, the blanket put onto a plate graphic tinplate, is the principle of offset printing. Because of tinplate with special physical and chemical properties of D and re-processing of printed matter, its ordinary offset printing process are quite different.
Tinplate printing ink has special requirements:
(1) An ink having a good adhesion and mechanical properties
Because ultimately be made of tinplate printed tin box, moon cake box, tea, canned food, toys, chemical products, metal frame and barrels, cans, subject to clipping, bending and stretching process, which requires printing inks for tinplate has good adhesion and corresponding mechanical properties. In order to improve ink adhesion, before printing tinplate first need to be white primer. White is the color of all of the screen, a high brightness. After joining the hue of other high energy level, and can improve the brightness and hue of each color scale formation.
(2) the requirement for white ink
Tinplate surface was white (or yellow), with a metallic sheen, before printing color graphics, the need to print white painted white or restrict the ability of the affected ink coverage, monochrome machines often subject to two times a printed white, its whiteness up to 75%. Whiteness as a tinplate printing an important indicator of the quality of products, requiring white ink has a good combination of power and primer, after repeated high temperature baking non-yellowing, high temperature steam will not go color. Were primed for tinplate, tin can increase the adhesion of white ink with good adhesion. Common amine type epoxy primer, with a light color, after repeated baking non-yellowing, aging characteristics and flexibility, impact resistance of process performance.
(3) the requirements of the color ink
Tinplate printing color inks, in addition should have a certain degree of water resistance, need to have their special requirements. Because of tinplate impermeable surface water and solvent, need to go through baking dry, and therefore it should be heat-curable ink. Coloring pigments require a higher strength and durability. Printing inks in addition to the general performance should have basic offset printing ink, but according to the characteristics of Indian iron should also have heat resistance, the ink film adhesion, impact resistance, hardness, good resistance to cooking and light features.
(4) Ink Drying Process
In the production of tinplate printing, ink drying is a complex physical and chemical reaction process. To the reasonable control of the ink drying speed, master of the physical and chemical ink drying mechanism, in order to effectively carry out fast printing operations to ensure product quality. Ink drying too quickly will reduce the normal transfer properties of the ink, affecting the normal production; cause blot hair is true, ink hair short, printing plates, ink roller surface appear inks dry, the lower the ink to pass the blocked; make printing plates Graphic dry outward expansion layer; desiccant adsorption increases caused by ink, dirt, etc. from a blank part of the phenomenon of excessive use. The ink drying too slow can be caused by overprinting difficulties, adhesion, adhesion, etc., firmness lower; easily cause scratches and other transmission process. So the ink drying speed should be appropriate, too fast too slow are unfavorable.
Special structure (5) printing equipment
Because of different substrates, tinplate printing auxiliary organizations also different from offset printing paper. Tinplate insoluble in water, does not adsorb solvent, the printing ink to be baked at high temperature in order to evaporate the solvent conjunctiva cured. Therefore printing technology devices generally required with drying room. Tinplate printing automatic line generally throughout the full length of about more than 50 meters, with sophisticated features huge. In addition, the use of magnets points tinplate printing sheets and double sheet control, high hardness tinplate material also determines the printing process can not lose the use of advanced continuous iron structure in the push families, quasi-bit architecture and stacking section are different from Offset printing paper.
