Drive unit for liquid ejection head and liquid ejection apparatus provided with such unit

A liquid ejection apparatus comprising a liquid ejection head provided with a piezoelectric thin film and a drive unit in which ejection of liquid is caused by contract of a pressure chamber that is caused by the application of a voltage to a piezoelectric thin film,

• wherein the natural period of said pressure chamber during damped meniscus vibrations after liquid ejection is made shorter than the natural period during the liquid ejection by said drive unit,
• wherein the polarization generated in said piezoelectric thin film during voltage application is no less than 0.25 C/m2.

A drive unit for a liquid ejection head in which ejection of liquid is cause by contract of pressure chamber that is caused by the application of a voltage to a piezoelectric thin film,

• wherein the voltage applied to said piezoelectric thin film has an electric potential stable period in the course of returning from an electric potential when pressure chamber has contracted for the ejection of liquid to another electric potential prior to a drive for the next ejection, and
• wherein the polarization generated in said piezoelectric thin film during voltage application is no less than 0.25 C/m2.

A liquid ejection apparatus comprising a liquid ejection head provided with a piezoelectric thin film and a drive in which ejection of liquid is caused by contract of a pressure chamber that is caused by the application of a voltage to a piezoelectric thin film,

• wherein the voltage applied to said piezoelectric thin film by said drive unit has an electric potential stable period in the course of returning from an electric potential when pressure chamber has contracted for the ejection of liquid to another electric potential prior to a drive for the next ejection, and
• wherein the polarization generated in said piezoelectric thin film during voltage application is no less than 0.25 C/m2.

A liquid ejection apparatus comprising a liquid ejection head provided with a piezoelectric thin film and a drive unit in which ejection of liquid is caused by contract of a pressure chamber that is caused by the application of a voltage to a piezoelectric thin film.

• wherein the voltage applied to said piezoelectric thin film by said drive unit has an electric potential stable period in the course of returning from an electric potential when pressure chamber has contracted for the ejection of liquid to another electric potential prior to a drive for the next ejection, and
• wherein the time period from the ending of said pressure chamber contract to the beginning of said potential stable period is shorter than the natural period of said pressure chamber during the liquid ejection, and
• wherein polarization generated in said piezoelectric thin film during voltage application in no less than 0.25 C/m2.