Patent ID: 6350012
Filing Date: 2002-02-26
Classification: B41J

Abstract:
A method of cleaning a surface of an acoustic ink printhead, which holds ink between a lower glass substrate and an upper orifice plate, and which ejects droplets of the ink through orifices of the orifice plate when an acoustic wave of a predetermined magnitude is exerted on a free surface of the ink corresponding to the orifices, the method comprising:moving a capping station having a cap portion into alignment with the printhead; engaging a surface of the printhead and the cap portion so as to create a substantially air tight seal between the surface of the printhead and a surface of the cap portion, with a small gap area existing within the cap portion; flooding the printhead by increasing ink pressure within the printhead to a level which causes ink to escape through the orifices and filling the small gap inside the cap portion; maintaining the flooding step for a predetermined amount of time, whereby the ink acts to dissolve dried ink and loosen debris on the printhead; altering and maintaining the ink pressure to an intermediate level which prevents the ink remaining inside a bore of each orifice from reentering the printhead; opening a vent valve on the cap portion, to drain at least a portion of the ink which escaped through the orifices; disengaging the capping station and the printhead; aligning a wiping station and the printhead such that an absorbent material positioned around a compliant wiping roller is positioned across from the orifices; a first wiping step including, pushing the absorbent material lightly over the orifices with the compliant roller, while the printhead is moved, whereby due to the pressure inside the printhead which does not allow the ink to reenter the printhead, the ink is absorbed by the absorbent material; decreasing the pressure inside the printhead to a value substantially below operating pressure, whereby menisci retreats inside orifice lips of the corresponding orifices of the printhead; a second wiping step including, pushing a new portion of the absorbent material onto the surface of the printhead with a force greater than the force of the previous pushing step, whereby pushing with a greater force allows the new portion of the absorbent material to absorb remaining ink into the new portion of the absorbent material from each orifice as well as from an outer surface of the orifice lips; and returning the ink pressure to normal operating level to enable resumption of printing.