Sheet prodn. process for producing watermarks in thermal printer - involves heating proof material carrying film in dot form to transmit proof material to sheet

摘要

The process involves overlapping a proof material provided film with the sheets to be processed. The film is heated up in dot form to transmit the proof material e.g. wax to a special section of the sheets to be processed. The to be processed sheets may be further impregnated with the proof material to increase the transparency of the glass level of the special sections of the sheets. USE/ADVANTAGE - Efficient process for prodn. of watermarks which enables an increased flexibility in the selection of the form and the pattern of the watermark.