Ink-jet head and ink-jet printer having ink-jet head

An ink-jet printer including an ink-jet head, the ink-jet head comprising:

• a passage unit including a plurality of pressure chambers each having one end coupled to a nozzle and the other end to be coupled to an ink supply source, the plurality of pressure chambers being arranged in a matrix to neighbor each other;
• and
• an actuator unit attached to a surface of the passage unit for changing the volume of each of the pressure chambers,
• the actuator unit comprising:
• a plurality of piezoelectric sheets disposed to continuously extend over the chambers, wherein an uppermost piezoelectric sheet is an active layer that is deformed when an external electric field is applied;
• a common electrode disposed on one side of the uppermost piezoelectric sheet and kept at a constant potential;
• a plurality of individual electrodes disposed on the other side of the uppermost piezoelectric sheet at positions respectively corresponding to the pressure chambers;
• and
• recesses formed in regions of the piezoelectric sheet corresponding to portions between the pressure chambers, wherein the recesses suppress a deformation that propagates in a plane direction of the uppermost piezoelectric sheet.

An ink-jet head comprising:

• a passage unit including a plurality of pressure chambers each having one end coupled to a nozzle and the other end being able to be coupled to an ink supply source, the plurality of pressure chambers being arranged in a matrix to neighbor each other;
• and
• an actuator unit attached to a surface of the passage unit for changing the volume of each of the pressure chambers,
• the actuator unit comprising:
• a piezoelectric sheet disposed to continuously extend over the pressure chambers;
• a common electrode disposed on one side of the piezoelectric sheet, the common electrode kept at a constant potential;
• a plurality of individual electrodes disposed on the other side of the piezoelectric sheet at positions respectively corresponding to the pressure chambers;
• and
• recesses formed in regions of the piezoelectric sheet corresponding to portions between the pressure chambers, wherein one or more inactive layers each made of a piezoelectric sheet are disposed between the piezoelectric sheet and the passage unit, and the recesses suppress a deformation that propagates in a plane direction of an uppermost piezoelectric sheet.

An ink-jet printer including an ink-jet head, the ink-jet head comprising:

• a passage unit including a plurality of pressure chambers each having one end coupled to a nozzle and the other end to be coupled to an ink supply source, the plurality of pressure chambers being arranged in a matrix to neighbor each other;
• and
• an actuator unit attached to a surface of the passage unit for changing the volume of each of the pressure chambers,
• the actuator unit comprising:
• a piezoelectric sheet disposed to continuously extend over the pressure chambers;
• a common electrode disposed on one side of the piezoelectric sheet and kept at a constant potential;
• a plurality of individual electrodes disposed on the other side of the piezoelectric sheet at positions respectively corresponding to the pressure chambers;
• and
• recesses formed in regions of the piezoelectric sheet corresponding to portions between the pressure chambers, wherein one or more inactive layers each made of a piezoelectric sheet are disposed between the piezoelectric sheet and the passage unit, and the recesses suppress a deformation that propagates in a plane direction of an uppermost piezoelectric sheet.

An ink-jet head comprising:

• a passage unit including a plurality of pressure chambers each having one end coupled to a nozzle and the other end being able to be coupled to an ink supply source, the plurality of pressure chambers being arranged in a matrix to neighbor each other;
• and
• an actuator unit attached to a surface of the passage unit for changing the volume of each of the pressure chambers,
• the actuator unit comprising:
• a plurality of deformable sheets including one or more piezoelectric sheets disposed to continuously extend over the chambers, wherein an uppermost piezoelectric sheet is an active layer that is deformed when an external electric field is applied;
• a common electrode disposed on one side of the uppermost piezoelectric sheet, the common electrode kept at a constant potential;
• a plurality of individual electrodes disposed on the other side of the uppermost piezoelectric sheet at positions respectively corresponding to the pressure chambers;
• and
• recesses formed in regions of the uppermost piezoelectric sheet corresponding to portions between the pressure chambers, wherein the recesses suppress a deformation that propagates in a plane direction of the uppermost piezoelectric sheet, wherein:
• each of the pressure chambers is substantially rhombic and are arranged in a matrix so that sides of the pressure chambers are parallel with each other,
• each of the individual electrodes have a shape similar to a shape of each of the pressure chambers,
• each of the recesses is formed so as to substantially enclose the corresponding one of the pressure chambers,
• each of the recesses is formed along an edge of the corresponding one of the pressure chambers, and
• each of the recesses is formed so as to correspond to a region other than an acute portion of the corresponding one of the individual electrodes.