Offset printing is currently the most common and commonly used printing method for iron box printing. At present, most of the iron printing machines use flat offset printing for tinplate printing processing. Because the printing format of the iron printing machine is not fixed, its application will be limited to a certain extent. With the development of technology, this tinplate offset printing press is also constantly improved. At present, tinplate offset presses that can change the printing format have been successfully developed. After improvement and installation of some parts, it can be used for brushing iron materials and printing UV prints.
Characteristics of tinplate offset printing
1. Tinplate printing belongs to offset printing, but compared with general offset printing, it has its own characteristics:
2. The substrates for tinplate printing are various metal sheets. At present, the substrates used for tinplate printing are tin-plated sheet steel (tinplate), chrome-plated sheet steel, ordinary sheet steel, and aluminum alloy sheet. These metal sheets of iron box manufacturers can be divided into three types: hard iron sheet, neutral iron sheet and soft iron sheet according to their different hardness. Aluminum alloy sheet is soft, ordinary sheet steel is neutral, and chrome-plated sheet steel is rigid. During the printing process, depending on the hardness of the substrate, adjust the pressure of the cylinder and select the appropriate lining material.
3. For use in cans, it is required that the printed iron ink is resistant to high temperature and cooking, and is non-toxic and harmless.
4. The printing operation is different from a coating which plays a decisive role in the quality of iron sheet printing. The coating can increase the adhesion between the iron sheet and the ink layer and protect the ink film layer.
5. Use special printing ink. As the tinplate printed substrates have smooth surfaces and do not have the ability to absorb, tinplate printing inks rely on oxidized conjunctiva and volatile drying. At the same time, tinplate prints generally require offset printing. When manufacturing the printing machine, the blowing force of the blowing nozzle and the suction force of the suction nozzle must be considered, and a horseshoe-shaped magnet is added at the feed to overcome the adsorption force between the iron plates. During the operation, the air volume of the mouthpiece and the suction nozzle should be adjusted according to different weight substrates. The adjustment of the drum pressure is the key to the operation. In addition to adjusting the thickness of the substrate, you must also consider the transfer of the dots.