Dual reservoir and valve system for an ink jet head

摘要

In the representative ink supply system described in the specification, continuous circulation of ink in an ink jet head is accomplished by providing two reservoirs connected to each ink jet orifice through corresponding passages so that ink flows continuously from a high-level reservoir past the orifice to a low-level reservoir. The difference between the levels of ink in the reservoirs is maintained relatively constant by inertial pumping during reciprocal motion of the ink jet head or by pressure transfer of ink from one reservoir to the other reservoir. Cross-flow purging of air or debris from the ink jet head is effected by covering the ink jet orifices and applying air pressure to one reservoir to cause ink and any trapped air or debris to flow from the head to the other reservoir. A pump responsive to reciprocal motion of the ink jet head generates a positive air pressure which is applied during purging and a negative air pressure which is applied to a deaerator for removing dissolved air from the ink.