Fluid drop ejection
A drop ejection system includes a flow regulator that can regulate the fluid flow to enhance fluid purging from the fluid ejection head and other system operations. The drop ejection system can include a drop ejection head with a plurality of nozzles, a pumping chamber, and a fluid purge unit capable of purging the fluid from the nozzles by generating a negative pressure outside of nozzles. The flow regulator can increases the flow resistance of the fluid flow to the drop ejection head when the fluid is purged out of the nozzles.
1 . A drop ejection system, comprising:
a drop ejection head comprising a plurality of nozzles adapted to eject a fluid;
a pumping chamber adapted to supply the fluid to the drop ejection head;
a fluid purge unit capable of purging the fluid from the nozzles by generating a negative pressure outside of nozzles; and
a flow regulator that is configured to increase the flow resistance of the fluid flow to the drop ejection head when the fluid is purged out of the nozzles.
2 . The drop ejection system of claim 1 , wherein the drop ejection head is an ink jet print head comprising a plurality of ink jet nozzles adapted to eject an ink fluid.
3 . The drop ejection system of claim 1 , wherein the flow regulator is capable of regulating the fluid flow into the pumping chamber.
4 . The drop ejection system of claim 1 , wherein the flow regulator is a passive device.
5 . The drop ejection system of claim 1 , wherein the flow regulator is an active device.
6 . The drop ejection system of claim 1 , wherein the flow regulator is controlled by a control unit in response to the modes of operation of the drop ejection system.
7 . The drop ejection system of claim 1 , wherein the flow regulator includes one or more of a variable valve, solenoid valves, servo valves, and a flow resistance in parallel to an open/shut bypass valve.
8 . The drop ejection system of claim 1 , wherein the fluid purge unit comprises
a nozzle cap that can seal the nozzles air-tight from the ambient air; and
a pump that can pump air out of the air-tight space formed by the nozzle cap and the fluid ejection head, thereby generating the negative pressure for purging the fluid out of the nozzles.
9 . The drop ejection system of claim 8 , further comprising a mechanism for moving the nozzle cap to engage with and disengage from the nozzles.
10 . The drop ejection system of claim 1 , wherein the fluid purge unit is capable of purging the fluid from a subset of the nozzles in a fluid ejection head.
11 . The drop ejection system of claim 1 , further comprising a deaerator in fluid contact with the fluid along a flow path supplying fluid to the drop ejection head, wherein the deaerator is capable of removing dissolved gas from the fluid.
12 . The drop ejection system of claim 1 , further comprising a transport mechanism that produce relative movement between the drop ejection head and a receiver to permit the receiver to receive fluid drops ejected from the nozzles.
13 . A method for purging a fluid ejection head, comprising:
supplying a fluid along a fluid path to the fluid ejection head having a plurality of nozzles;
increasing the flow resistance to the fluid along the flow path; and
purging the fluid from the fluid ejection head.
14 . The method of claim 13 , wherein the fluid is purged through the nozzles.
15 . The method of claim 14 , wherein purging the fluid from the region includes applying a negative air pressure to the nozzles.
16 . The method of claim 13 , wherein purging the fluid from the region includes applying a negative air pressure an outlet of the fluid ejection head.
17 . The method of claim 13 , wherein increasing the flow resistance to the fluid along the flow path occurs before or during purging fluid from the nozzles of the fluid ejection head.
18 . The method of claim 13 , further comprising reducing the flow resistance to the fluid along the fluid path.
19 . The method of claim 18 , wherein reducing the flow resistance to the fluid along the fluid path occurs during or after purging ink from the nozzles of the fluid ejection head.
20 . The method of claim 13 , further comprising determining the execution of purging the ink from the ink jet nozzles by tracking one or more of the duration of the idle time of the ink jet print head, the acceleration of the ink jet print head, and the ink filling status of the ink jet print head.
21 . The method of claim 20 , further comprising tracking the duration of the idle time of the fluid ejection head.
22 . The method of claim 20 , further comprising tracking the acceleration of the fluid ejection head.
23 . The method of claim 20 , further comprising tracking the fluid filling status of the fluid ejection head.
24 . The method of claim 13 , wherein increasing the flow resistance occurs upstream of the fluid ejection head.
25 . The method of claim 13 , wherein the fluid ejection head is an ink jet print head comprising a plurality of ink jet nozzles adapted to eject an ink.
26 . The method of claim 25 , further comprising wiping a nozzle plate of the ink jet print head.
27 . The method of claim 25 , further comprising ejecting ink drops from the ink jet nozzles.
28 . The method of claim 25 , further comprising supplying ink from an ink reservoir to a pumping chamber in the ink jet print head.
29 . The method of claim 28 , wherein increasing the flow resistance occurs at a passage supplying ink to the pumping chamber.