Inkjet printhead and inkjet image apparatus
AssigneeSharp Kabushiki Kaisha
InventorsTakeshi Kameda, Hiroshi Ishii
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Abstract
An inkjet printhead and an inkjet image forming apparatus capable of achieving improved ink jetting performance as a result of causing partition(s) partitioning ink chamber(s) of inkjet printhead(s) to be made up of piezoelectric member(s) for which rate(s) of change of electromechanical coupling coefficient(s) with respect to temperature display negative characteristics, or causing partition(s) partitioning ink chamber(s) of inkjet printhead(s) to be made up of piezoelectric member(s) for which rate(s) of change of electromechanical coupling coefficient(s) with respect to temperature display positive characteristics and controlling electrical energy supplied to such piezoelectric member(s) based on image data and ink temperature.
Claims8
In the context of an inkjet printhead wherein electrical energy is supplied to one or more piezoelectric members making up at least one wall of one or more ink chambers, causing deformation of at least one of the piezoelectric member or members, as a result of which at least a portion of the ink within at least one of the ink chamber or chambers is jetted toward one or more recording media,
- an inkjet printhead characterized in that one or more rates of change with respect to temperature, of one or more electromechanical coupling coefficients of the piezoelectric member or members, exhibits negative characteristics.
In the context of a multidrop-type inkjet printhead wherein electrical energy is supplied to one or more piezoelectric members making up at least one wall of one or more ink chambers, causing deformation of at least one of the piezoelectric member or members and permitting a plurality of consecutively jetted ink droplets to be made to combine to form a single dot on recording medium or media,
- an inkjet printhead characterized in that one or more rates of change with respect to temperature, of one or more electromechanical coupling coefficients of the piezoelectric member or members, exhibits negative characteristics.
In the context of an inkjet printhead wherein electrical energy is supplied to one or more piezoelectric members making up at least one wall of one or more ink chambers, causing deformation of at least one of the piezoelectric member or members, as a result of which at least a portion of the ink within at least one of the ink chamber or chambers is jetted toward one or more recording media,
- an inkjet printhead characterized in that it is constructed such that, taking ink viscosities at ink temperatures Ta (° C.) and Tb (° C.) to respectively be ηa and ηb, taking electrical capacitances of the piezoelectric member or members at those temperatures to respectively be Ca and Cb, taking electromechanical coupling coefficients of the piezoelectric member or members at those temperatures to respectively be Ka and Kb, and taking voltages supplied so as to cause deformation of at least one of the piezoelectric member or members at those temperatures to respectively be Va and Vb, the supplied voltages are set so as to satisfy
- (Va/Vb)2=α2×(Cb×Kb2×ηa)/(Ca×Ka2×ηb)
- where 0.93≦α≦1.14.
In the context of an inkjet image forming apparatus equipped with one or more inkjet printheads wherein electrical energy is supplied to one or more piezoelectric members making up at least one wall of one or more ink chambers, causing deformation of at least one of the piezoelectric member or members, as a result of which at least a portion of the ink within at least one of the ink chamber or chambers is jetted toward one or more recording media,
- an inkjet image forming apparatus characterized in that it is provided with one or more means for controlling at least a portion of the electrical energy supplied to at least one of the piezoelectric member or members based on image data and ink temperature;
- and
- one or more rates of change with respect to temperature, of one or more electromechanical coupling coefficients of the piezoelectric member or members, exhibits positive characteristics.
Dependencies are inferred from the claim text.