INK FOR CONTINUOUS INK JET PRINTING

摘要

An ink which is to be used for high resolution continuous ink jet printing may also contain, in contrast to current knowledge, water insoluble colouring agents in dispersed form. The known problems associated with such inks stem from the additives which are necessary for the stabilisation of the ink, and from a badly adapted size distribution of the colouring agent particles. Thus, additives should be preferred whose average molecular weight is less than 20,000. With substances that are hydrogen bridge active, in particular that contain hydroxy or amino groups, this limit must be still lower, i.e. about 1,000. The particles of the colouring agent should have a size distribution wherein the colouring agent's total volume proportion of particles greater than 200 nm is less than about 10 %, and that of particles greater than 300 nm less than about 3 %.