Patent ID: 8500232

Claim:
A head chip for an ink jet type image forming apparatus comprising: a substrate having an ink supply port for ink supply; a plurality of nozzles to eject ink; a channel forming layer disposed on the substrate to form ink channels between the ink supply port and the nozzles; a plurality of heaters for ink ejection provided in the ink channels to apply heat to ink so that the ink is ejected through the plurality of nozzles; and a closed-loop cooling channel integrally formed in the head chip and having at least one pumping part to circulate a refrigerant through a supply channel, a first circulation channel, a second circulation channel, and a discharge channel, the first and second circulation channels being formed in the head chip adjacent to and around the plurality of heaters for ink ejection, the first and second circulation channels and a portion of the supply channel and the discharge channel being formed in the channel forming layer, and another portion of the supply channel and the discharge channel being formed in the substrate.