Flat Screen Printing

Flat screens are not suitable coloration units for a truly continuous process, and in all the successful machines for fully automatic flat-screen printing the colour is applied through the screens while the fabric is stationary.

The main features of a typical automatic flat-screen machine are illustrated in Figure 2.5 and shown diagrammatically in Figure 2.6. All the screens for the design (one screen for each colour) are positioned accurately along the top of a long endless belt, known as a blanket. A machine intended to print traditional furnishing designs might have space for 15 or more screens. The width of the gap between the areas printed by any two adjacent screens must be a whole number of lengthways design
repeats. This need not necessarily be the same as the lengthways screen repeat as there may be several design repeats per screen repeat; for example, where there are three design repeats per screen repeat, the gap between adjacent screens need only be one-third of a screen repeat. The fabric is gummed to the blanket at the entry end and moves along with the blanket in an intermittent fashion, one screen-repeat distance at a time. All the colours in the design are printed simultaneously while the fabric is stationary; then the screens are lifted and the fabric and blanket move on. When the fabric approaches the turning point of the blanket, it is pulled off and passes into a dryer. The soiled blanket is washed and dried during its return passage on the underside of the machine.