An ink jet printing system

摘要

An ink jet printing system comprising: a droplet generator (5) for generating at least one stream of ink droplets; a supply tank (3) for supplying ink to said generator (5); supply transfer means (1) for driving the ink from said tank (3) to said generator (5); a holding tank (101) for receiving liquid issued by said generator (5) during preparation of the system for subsequent printing, said holding tank (101) being connected to said supply tank (3) for the supply of said liquid to the supply tank (3) during said subsequent printing; and means (21, 23, 25) for determining during said subsequent printing the times at which the composition of the ink supplied to said generator (5) is such that it is appropriate to use the liquid contained in said holding tank (101).