Patent ID: 7517065
Filing Date: 2009-04-14
Classification: B41J

Abstract:
1. An inkjet printhead for ejecting ink droplets for printing, the inkjet printhead comprising: a plurality of nozzles through which the ink droplets are ejected, disposed such that a plurality of nozzle arrays each extending in a first direction are arranged in a second direction orthogonal to the first direction; a cavity unit incorporating a plurality of pressure chambers corresponding to the plurality of nozzles, respectively, the plurality of pressure chambers being disposed such that a plurality of pressure-chamber arrays each extending in the first direction are arranged in the second direction; and an actuator including a plurality of energy generation areas selectively imparting ink ejecting energy to the plurality of pressure chambers, respectively, the actuator being in the form of a laminate of a plurality of sheets, and in superposed relationship on the cavity unit, wherein the actuator includes a plurality of individual electrodes corresponding to the plurality of energy generation areas, respectively, and includes a top sheet of the plurality of sheets which is distal from the cavity unit, wherein the top sheet includes a plurality of bonding terminations for selectively imparting electrical energy to the plurality of energy generation areas, respectively, the plurality of bonding terminations being disposed on a surface of the top sheet so as to form individually separated lands, wherein the inkjet printhead is bonded at the plurality of bonding terminations to a plurality of bonding electrode areas of a flexible flat cable, respectively, in superposed relationship thereon, for use in reception of control signals for controlling the inkjet printhead, via the flexible flat cable, wherein the plurality of bonding terminations include a plurality of surface electrodes formed on a surface of the top sheet, respectively, wherein the top sheet includes a plurality of through holes each piercing through the top sheet in a thickness direction thereof, each of the plurality of through holes being filled with a conductive material, wherein the conductive material filling a corresponding one of the plurality of through holes, is locally communicated with a corresponding one of the plurality of the surface electrodes at a communication portion thereof, thereby to electrically couple the corresponding surface electrode and a corresponding one of the plurality of individual electrodes of the actuator, wherein the top sheet includes a plurality of external conductive areas, each formed on a surface of a corresponding one of the plurality of surface electrodes, and each having a thickness larger than that of the corresponding surface electrode, wherein each of the external conductive areas is formed, so as to overlay an open end of the corresponding through hole located in the communication portion of the corresponding surface electrode, and so as to be tightly joined to the open end, wherein each of the plurality of external conductive areas comprises an external electrode bonded to a corresponding one of the plurality of bonding electrode areas of the flexible flat cable, in superposed relationship thereon, and wherein the plurality of surface electrodes are categorized at least into a first surface-electrode group having both the corresponding external electrode and a dummy portion not bonded to any bonding electrode area, and a second surface-electrode group having the corresponding external electrode without the dummy portion.