PURPOSE: To enable the prevention of clogging along with a smooth discharge of bubbles by providing a head holder having a check valve in an upper counterflow passage and a head having a bubble discharge channel to introduce bubbles being trapped.
CONSTITUTION: In order to discharge bubbles mixed-in from outside through a tube due to a prolonged unused state without printing or those mixed from a ink feed needle during the loading or unloading of an ink cassette, a cap 36 puts on a nozzle section at the home position. When printing is unabled during the printing operation, first, confirmation is made to see that ink is empty. When it is not empty, the carriage is returned to the home position and after the cap 36 is put on the nozzle section, a negative suction recovery pump is put into operation to suck out bubbles in a head liquid chamber section or ink feed path together with ink. A check valve 31 of the head holder 26 opens when the negative pressure exceeds a specified level to discharge outside the bubbles accumulated in an expanded passage 28 through a trapped bubble discharge conduction channel 32.
ISAYAMA TAKUO
AMEYAMA MINORU
MATSUMOTO SHIYUUZOU
KATANO YASUO
