Patent ID: 7802879

Claim:
An ink refill unit for a print engine, the unit comprising: a body assembly defining an ink ejection port at one end thereof; a compressible tank located inside said body assembly; and a compression arrangement for compressing the tank, said arrangement comprising: actuation means selectively operable by a controller of the print engine; a threaded wall and circular plunger assembly; and an elongate drive gear mounted within the body assembly and engaging with the plunger assembly, said drive gear actuated by the actuation means, wherein the threaded wall and circular plunger assembly includes an internal lead screw provided in a substantially cylindrical internal wall of the body assembly and a helical geared thread provided about the circumference of a substantially circular plunger threaded to the internal lead screw thread and extending along a length thereof, wherein the lead screw thread is provided with a gap along the length of the body assembly in which the drive gear sits and is able to come into contact with the geared thread of the plunger.