Inkjet technology vs. rotary screen printing
Rotary screen printing requires a screen for each colour in every design. The number of colours can go up to twenty-four. Let us have a look at the situation for a twelve colour design. For a design consisting of 12 twelve colours, twelve screens are needed only usable for that specific design. During production a certain amount of print paste needs to be made to ensure the quality throughout the whole lot. At the end of the run printing paste remains in the screens, becoming waste. The screens need to be washed and cleaned creating waste water containing colours and therefore a special discharge or treatment is necessary.
Figure 1: Waste creation in 1) vessel, 2) pump, 3) screen
When the printing changes to ink jet, these forms of waste are no longer created, the only waste generated is the waste of during maintenance of the print heads.
Another aspect creating waste is the expected need of customers and the number of steps following the printing stage. Especially the coating step, in which the requested colour needs to be made, is crucial for the amount of waste. Again the amount of coating needs to be made in a slightly higher amount than strictly needed. A certain amount of paste remains in the vessel, pump and in front of the coating knife.
When the product set-up is changed to print the requested colour on the outside, instead of a coloured coating, the waste of the coating process will reduce tremendously. The change in set-up requires for one standard white coating to guarantee the product performance. At the same time this opens the way to mass customization, making superfluous and unsalable stock something of the past.
Figure 2: Drop generation and impact during inkjet dispensing process are influenced by material properties and other effects