Plain Label Die Cutting Machine unwinding and rewinding tension are auto-controlled by magnetic powder brake and clutch, two rewinders are possible in this machine.
The length of the tape between the two printing parts (units) on the flexo press is 250-400mm, and the flexo speed is generally 150m/min, which means that the time on the roll passes through the drying device is only a fraction Up to tenths of a second, therefore, the drying device of the flexographic printing machine is required to have good drying efficiency.
The drying device of the flexographic printing machine is divided into two stages: one level is inter-color drying, that is, the front color ink layer is dried as completely as possible before entering the next printing unit, and the other level is final drying, that is, all the inks in each color. After printing, the solvent in the ink layer should be completely eliminated to avoid filth failure during rewinding or stacking.
1. Drying parts for flexo presses using water-based or solvent-based inks
Such dry parts are dried by heating and drying, and the heating elements are hot air tubes and infrared light tubes. After heating and drying, the solvent in the ink layer is volatilized, but since the ink layer is heated during drying, the grease in the ink connection material may still be in a sticky state, and a cooling device must be installed to cool it so as not to be rewinded. Or the processing speed and curing temperature of the curing resin and flexo printing machine are high, and the cooling roller or other cooling device must be installed with high thermal efficiency, and the dry hot air does not escape from the wind hood, so as to avoid The ink on the plate has an adverse effect.
There are two ways to install the heating and drying unit: one is installed in the lower part of the flexographic printing unit. This way the structure is solid. It can reduce the space occupied by the machine; the other is installed in the upper part of the flexographic printing unit. It is obvious that the heat generated during heating and drying is dissipated upwards, which will not adversely affect other components. This is the current mainstream.
There are two additional points to be added here:
1. Due to the high printing speed and dry heating temperature of the flexographic printing press, it is necessary to install a cooling roller or other cooling device to cool the printing material (roll) to avoid the roll (especially PVC plastic). Films, thin papers, etc.) cause shrinkage, warpage, thermal expansion and other undesirable phenomena during heating and drying;
2. In order to reduce the volatile organic compounds (VOCS) that escape from solvent-based inks during heating and drying, VOCS should be used. Post-processing equipment. There are two main types of post-treatment methods, catalytic oxidation and cooling recovery.