A squeegee (from the French racle ) is a tool to wipe off excess viscous substances or to smooth films.
In the printing technology there are two types of the doctor:
In gravure printing , the squeegee is a knife-like ground steel strip with or without a supporting squeegee. It serves to wipe off the excess printing ink from the webs of the printing cylinder so that only the cells are filled with ink. This process is called doctoring . In flexographic printing , the squeegee is used to remove excess ink from the webs of the anilox roller . In planographic printing , this tool has a similar function as in gravure printing and is used to remove the ink from the inking rollers. However, this does not happen during printing, but only when changing colors or at the end of work.
With screen printing, however, the pressure squeegee is made of rubber or plastic with a sharp or rounded edge. In the past, this tool was also available in a form similar to a knife. This knife was made of wood or metal. It is used to press the printing ink through the openings in the screen onto the printing material . The squeegee, which is also partially provided with a felt or rubber edge, is moved back and forth.
This can result in doctor streaks .
In coating systems z. Various types of doctor blades are used , for example, for textile finishing :
- Blanket squeegee
- Box doctor blade
- Air knife
- Knife squeegee
- Magnetic squeegee
- Spiral doctor blade
- Support squeegee
- Table squeegee
- Roller doctor blade
When painting with oil, the squeegee is the scraper for excess paint.
The painter Karl Otto Götz worked with the squeegee, and his student Gerhard Richter also used it to draw it over a canvas when the colors on it were still damp, to create random patterns. The painter Walter Zimmermann used the squeegee instead of the brush in order to turn away from representational painting as radically as possible in favor of pure color.
In the labeling technique used and advertising technology plastic spatula or Filzklötzchen with which self writings or graphics such. B. digitally printed self-adhesive films, which have already been peeled off the mounting film, are pressed onto the object to be labeled. This type of squeegee is used for. B. from sign and illuminated advertising manufacturers .
- Scheper, Hans Jürgen: Examination knowledge printing technology . Itzehoe: Verlag Beruf und Schule, 2005. ISBN 3-88013-623-8