PURPOSE: To shorten refilling time by controlling unnecessary forcing back of ink to an upstream side by a method wherein a liquid passage has a constriction part wherein a sectional area normal to the liquid passage is minimized at a position corresponding to a heat action part to control a size of a bubble to be generated.
CONSTITUTION: By structuring a heat action part on a heating element part 1 so as to have a part wherein the sectional area of an ink passage is minimized on a discharge opening 12 side from a defoaming point 2 at a position corresponding to the heat action part, energy in foaming can be separated in a discharge direction and on an upstream side. Further, by concentrating even energy being transmitted upward in an ink passage in foaming by a structure slanting toward the discharge opening 12, discharge speed of the ink can be increased. On side angle (β) forming a minimized part H is made less than an angle (α) in order to lighten propagation of energy to the upstream side. Further, a surface on the discharge opening 12 side generates flow resistance to an ink flow from the discharge opening 12 side to decrease a regression side of a meniscus during a shrinking process of a bubble, which further generates a turbulent flow on the upstream side of the minimized part H to restrain the ink from moving to the upstream side.
KUBOTA HIDEMI
MAEOKA KUNIHIKO
NAKAJIMA KAZUHIRO
HIRASAWA SHINICHI
INUI TOSHIJI
TAKAHASHI HIROTO
