Creating erasable printing forme on magnetisable drum, by adhering toner image to make forme and laser removal of image after use

摘要

A printing machine has a printing cylinder (1) with magnetisable semiconductor surface (2). Image carrying areas of cylinder surface are magnetized to attract toner (3) which adheres to magnetized areas and not to unmagnetized areas. The toner is hardened or burnt onto the surface so cylinder is ready for printing. After printing, toner is removed by a laser unit (4) leaving surface ready for application of new toner image.