Silk screen printing

Advantages of screen printing:

• “high” covering ink application
• high gloss
• relief effect e.g. Braille or diorama (High Clear) high-class impression
• printing width up to 330 mm
• up to 4 colours
  

The printing plate’s equivalent of the screen printer is the screen – a wooden or aluminium frame with a fine nylon mesh stretched over it. The mesh is coated with a light sensitive emulsion or film, which, when dry, will block the holes in the mesh. The image that needs to be printed is output to film either by camera or image-setter. This film positive and the mesh on the screen are sandwiched together and exposed to ultra-violet light in a device called a print-down frame. The screen is then washed with a jet of water which rinses away any light sensitive emulsion that has not been hardened by the ultra-violet light. This results in an open stencil which corresponds exactly to the image that was supplied on the film. The screen is then fitted on the press and hinged so it can be raised and lowered. The substrate to be printed is placed in position under the screen and ink is placed on the top side of the screen. The frame also acts as a wall to contain the ink. A rubber blade, gripped in a wooden or metal handle called a squeegee, is then pulled across the top side of the screen to push the ink through the mesh onto the surface of the substrate being printed.
This is the only printing process in which the ink passes through the image carrier.

Rotary screen printing:
Rotary screen printing uses an alloy steel mesh formed into a hollow cylinder. The ink and the squeegee are inside this cylinder. The rotary printing allows continuous printing.