Power minimization for electrostrictive actuated printers

Claim 2

An electrostrictive actuator system for use in a printer including: an electrostrictive member; power supply means for applying a potential difference across the opposed surfaces of said electrostrictive member wherein said potential difference is effective to contract said electrostrictive member; a plurality of switching means connected in series to said power supply means, for discharging said potential difference across said electrostrictive member; divider means connected to said power supply means and said switching means, for reducing the potential across each of said plurality of switching means; timing means connected to said switching means for causing each of said switching means to selectively open thereby being effective to discharge said potential across said electrostrictive member and thereby causing said electrostrictive member to expand; and print means responsive to the expansion of said electrostrictive member for performing print operations.

Claim 3

The electrostrictive actuator system of claim 1 wherein said electrostrictive member is an elongated piezoelectric crystal having electrode positions on opposite sides thereof for receiving said potential difference.

Claim 4

The electrostrictive actuator system of claim 2 wherein said piezoelectric crystal has a predetermined time modulus of elasticity.

Claim 5

The electrostrictive actuator system of claim 1 wherein said power supply means includes a high voltage power supply that provides, in combination with said electrostrictive member, a charging time constant substantially longer than the discharging time thereby minimizing the maximum current to be provided by the said high voltage power supply.

Claim 6

The electrostrictive actuator system of claim 1 wherein said switching means includes transistors and additional circuit means electrically connected to said transistors for sequentially turning on said transistors commencing with the transistor electrically farthest from said power supply means thereby providing for a sequenced opening of said transistors so that none of said transistors are subject to excess voltage.

Claim 7

The electrostrictive actuator system of claim 5 wherein said divider means comprises a plurality of high resistant elements electrically connected to said power supply for supplying each of said transistors with a voltage proportional to the voltage value to that provided by said power supply means.

Claim 8

The electrostrictive actuator system of claim 1 wherein said print means includes an element guided for movement in a direction along a prescribed path of travel and capable of relative displacement with respect to one end of said electrostrictive member when said member is restored to its normal length by the discharge of said potential.

Claim 9

In a line printer: a plurality of print characters; a cyclically movable member, having said print characters disposed thereto in such a manner as to have each character traverse the print line of the printer as said cyclical member performs its cyclical motion; a row of electrostrictive elements extending parallel to the print line of the printer with one such element individually located at each print position thereof; a row of print hammers extending parallel to the print line of the printer in interposed relation between said row of electrostrictive elements and said cyclically movable member, said print hammers being individually associated with each of said electrostrictive elements and capable of being impelled by said electrostrictive elements toward said print characters; power supply means for applying a potential difference across the opposed surfaces of said electrostrictive elements wherein said potential difference is effective to contract said electrostrictive elements; a switch means, one associated with each of said electrostrictive elements, connected to said power supply means, for discharging said potential difference across said associated electrostrictive element; a divider means, one for each of said switch means, connected to said power supply means and its said associated switch means, for reducing the potential across selected elements of said associated switch means; and a timing means, one for each of said switch means, connected to said associated switch means for causing each of said associated switch means to open thereby being effective to discharge said potential across said associated electrostrictive element causing said electrostrictive element to expand thereby impelling said print hammers toward said print characters.

Claim 10

In a line printer: a plurality of print characters; a cyclically movable member, having said print characters disposed thereto in such a manner as to have each character traverse the print line of the printer as said cyclical member performs its cyclical motion; a row of electrostrictive elements extending parallel to the print line of the printer with one such element individually located at each print position thereof; a row of print hammers extending parallel to the print line of the printer in interposed relation between said row of electrostrictive elements and said cyclically movable member, said print hammers being individually associated with each of said electrostrictive elements and capable of being impelled by said electrostrictive elements toward said print characters; power supply means for applying a potential difference across the opposed surfaces of said electrostrictive elements wherein said potential difference is effective to contract said electrostrictive elements; a switch means, one associated with each of said electrostrictive elements, connected to said power supply means, for discharging said potential difference across said associated electrostrictive element; a divider means, one for each of said switch means, connected to said power supply means and its said associated switch means, for reducing the potential across selected elements of said associated switch means; and a timing means, one for each of said switch means, connected to said associated switch means for causing each of said associated switch means to open thereby being effective to discharge said potential across said associated electrostrictive element causing said electrostrictive element to expand thereby impelling said print hammers toward said print characters.

Claim 11

The line printer of claim 8 wherein said power supply means includes a high voltage power supply that provides, in combination with each individual electrostrictive element, a charging time constant substantially longer than the discharging time thereby minimizing the maximum current to be provided by said high voltage power supply.

Claim 12

The line printer of claim 8 wherein each of said electrostrictive elements is an elongated piezoelectric crystal having electrode positions on opposite sides thereof for receiving said potential difference.