VACUUM TYPE INK RETURN DEVICE IN INK JET PRINTER

摘要

A vacuum return ink system for an ink jet printing apparatus includes an ink/air separator comprising a housing having a chamber formed therein. A first inlet port of relatively large diameter connects the chamber via a short tube of similar diameter to the ink catcher of the printing apparatus used for accumulating unused ink. A second port of relatively large diameter is provided to connect the chamber via a tube of a similar diameter to a vacuum source. A third port of relatively small diameter is provided to connect the chamber via a tube of similar diameter to an evacuated ink return tank. A tubular section defining the third port is inserted into the housing with the end thereof extending to the floor of the chamber. Ink and air are drawn from the catcher into the chamber via the first port at a high rate of flow, thereby minimizing a buildup of ink at the catcher mouth. The ink having a higher inertial mass than the air is carried by gravity to the chamber floor where it is drawn into the small diameter tubular section and carried at a relatively low flow rate to the evacuated ink return tank, thereby minimizing solvent evaporation of the ink. The air flowing into the chamber from the catcher is carried therefrom to the vacuum source via the second port.