① The substrates of tinplate printing sheet are various metal sheets. At present, tinplate printing substrates are usually tinned sheet steel (also known as tinplate), chrome-plated sheet steel, ordinary sheet steel, and aluminum alloy sheet.
According to the different hardness of these metal sheets, the adjustment of the roller pressure is the key to operation. In addition to printing, it can be divided into three types: hard iron, neutral iron, and soft iron. Aluminum alloy sheet is soft, ordinary sheet steel is neutral, and chrome-plated sheet steel is rigid. In the printing process, it is necessary to adjust the cylinder pressure and select the appropriate lining material depending on the hardness of the substrate.
② Coatings play a decisive role in the quality of tinplate printing sheet. The coating can increase the adhesion between the print tinplate sheet and the ink layer and protect the ink film layer.
③ Use special printing ink. As the surface of tinplate printing substrates is smooth and does not have the ability to absorb, tinplate printing inks rely on oxidized conjunctiva and volatilization to dry.
At the same time, tinplate prints are generally used in cans after printing, which requires that the printed iron inks are resistant to high temperatures and cooking, and non-toxic.
④The printing operation is different from general offset printing. When manufacturing the printing machine, the blowing force of the blowing nozzle and the suction force of the mouthpiece should be considered, and a horseshoe magnet should be added at the feed to overcome the adsorption force between the iron plates.