1. Require ink with better adhesion and mechanical properties As custom printed tin boxes products to be made of food cans, toys, metal photo frames and chemical products barrels, and cans, need to be cut, bending and stretching process, thus requiring printing ink on tinplate with good adhesion and the corresponding mechanical properties. In order to improve the adhesion of the ink, the tinplate needs to be primed with white before printing. White is the base colour of all images and has a high degree of brightness. After adding other high-energy shades, it can improve the brightness of each shade and form a colour scale.   2. Requirements for white ink.  The printed tinplate boxes packaging surface is silvery white (or yellow), with a metallic lustre, before printing colour graphics, the surface needs to be painted white or printed white, limited by the ink coverage capacity, monochrome machines often need to be printed white by 2 times, the whiteness of up to 75%. Whiteness as an important indicator of the quality of tinplate printing products, white ink is required to have a good bond with the primer, by many high-temperature baking without yellowing, high-temperature resistant steam are not out of colour.   3. The requirements of the colour ink. Custom designs tin boxes colour ink, in addition to a certain degree of resistance to water performance, in addition, to need special requirements. As the tinplate surface does not penetrate water and solvents, it needs to be baked and dried, so its ink should be heat-curing type. The colouring power and durability of the pigments are required to be high. Printing iron ink should not only have the basic performance of the general offset ink, according to the characteristics of the printing iron should also have heat resistance, ink film adhesion, impact resistance, good hardness, resistance to cooking and light resistance and other characteristics.   4. The drying process of the ink. In tinplate printing production, the drying of ink is a complex physical and chemical reaction process. To reasonably control the drying speed of the ink, master the physical and chemical mechanisms in the drying of ink, in order to effectively carry out rapid printing operations, to ensure product quality. Ink drying too fast will reduce the normal performance of the ink transfer, affecting the normal production; resulting in a false print, ink colour is light, the printing plate, ink roller surface ink dry knot, so that the transfer of the next ink blocked; so that the printing plate graphic dry knot layer outward expansion; so that the desiccant with too much ink adsorption caused by the increase in the blank part of the dirty and other phenomena. And ink drying is too slow and can cause overprinting difficulties, adhesion, adhesion, etc., firmness is reduced; easy to cause the transmission process of scratching, etc.. So the drying speed of the ink should be appropriate, too fast and too slow are unfavourable.