Ink jet head having buffer tank in fluid communication with ink circulation pathway

摘要

To eliminate influence of air bubbles introduced into an ink jet head along with ink, an ink circulation pathway is provided which includes first to third ink channels. The first ink channel is connected between the sub-tank and a buffer tank to supply ink in the sub-tank to the buffer tank. The buffer tank is provided in a head unit to be mounted on an ink jet printer body. The second ink channel is connected between the buffer tank and the sub-tank. Any air or bubbles that have accumulated at the upper portion of the buffer tank can be discharged to the sub-tank by the pumping operation of a buffer purge pump disposed in the second ink channel. The third ink channel is connected between an ink cartridge and the sub-tank, and ink stored in the ink cartridge is supplied to the sub-tank through the third ink channel by the pumping operation of a ink supply pump disposed in the third ink channel when the ink stored in the sub-tank has gone below a certain fixed amount.