PRESSURE CONTROL DEVICE FOR INK PEN

摘要

PURPOSE: To sustain the back pressure suitably in the working range of a printhead suitably and to control the back pressure surely regardless of the orientation of a pen while keeping consistency. CONSTITUTION: Back pressure of an ink pen is sustained by providing capillary members 22, 24 contiguously to a bubble generator 18. The capillary member holds some quantity of ink contiguously to an orifice defined by the bubble generator regardless of the orientation of the pen. The some quantity of ink serves to supply a liquid seal being formed in the orifice. When the back pressure in the ink pen increases to the maximum level, the liquid in the orifice is overcome and a bubble of the ambient atmosphere flows into a tank 12 to lower the back pressure. When the back pressure returns back to a desired point, ink captured by the capillary member enters into the orifice to seal the orifice again.