Switched digital drive system for an ink jet printhead

Claim 3

The method of claim 1 wherein the step of imparting a series of voltage pulses of sequentially opposite polarities to the inwardly deflected wall portion to piezoelectrically drive the wall portion back to said initial undeflected position further comprises the steps of: imparting, for a first period of time, said first continuous polarity voltage to the wall portion; imparting, for a second period of time, said second continuous opposite polarity voltage to the wall portion, said second period of time shorter than said first period of time; and repeating the steps of imparting said first continuous polarity voltage and said second continuous opposite polarity voltage to the wall portion until the wall portion is driven back to said initial undeflected position.

Claim 4

The method of claim 2 and further comprising the step of selecting said first and said second period of time to control the driving back of the wall portion to said initial undeflected position.

Claim 5

An ink jet printhead comprising: a body having a spaced series of piezoelectrically deflectable actuation portions and a front end section with a spaced series of ink discharge orifices extending rearwardly therethrough; a spaced series of enclosed ink receiving channels, each of said channels longitudinally extending rearwardly through an interior of said body and opening outwardly through one of said orifices, each one of said channels being partially bounded by one of said actuation portions of said body; and drive means for actuating a selected one of said ink receiving channels, said drive means including: means for piezoelectrically deflecting a selected actuation portion partially bounding said selected one of said ink receiving channels, from an initially undeflected position thereof, inwardly into the selected one of said ink receiving channels, and means for imparting a series of driving voltage pulses of sequentially reversed polarities to said inwardly deflected actuation portion to piezoelectrically return said inwardly deflected actuation portion to said initially undeflected position; a series of electrical actuation leads, each of said electrical actuation leads operatively connected to a different one of said series of actuation portions; a series of switch means, each of said switch means connected to a different one of said electrical actuation leads and to positive and negative voltage sources; each of said switch means for creating a positive voltage in said electrical actuation leads operatively connected thereto in response to receipt of a first control signal and creating a negative voltage in said electrical actuation leads operatively connected thereto in response to receipt of a second control signal; and means for selectively transmitting said first and said second control signal to predetermined ones of said switch means.

Claim 6

An ink jet printhead comprising: a body having a spaced series of piezoelectrically deflectable actuation portions and a front end section with a spaced series of ink discharge orifices extending rearwardly therethrough; a spaced series of enclosed ink receiving channels, each of said channels longitudinally extending rearwardly through an interior of said body and opening outwardly through one of said orifices, each one of said channels being partially bounded by one of said actuation portions of said body; and drive means for actuating a selected one of said ink receiving channels, said drive means including: means for piezoelectrically deflecting a selected actuation portion partially bounding said selected one of said ink receiving channels, from an initially undeflected position thereof, inwardly into the selected one of said ink receiving channels, and means for imparting a series of driving voltage pulses of sequentially reversed polarities to said inwardly deflected actuation portion to piezoelectrically return said inwardly deflected actuation portion to said initially undeflected position; a series of electrical actuation leads, each of said electrical actuation leads operatively connected to a different one of said series of actuation portions; a series of switch means, each of said switch means connected to a different one of said electrical actuation leads and to positive and negative voltage sources; each of said switch means for creating a positive voltage in said electrical actuation leads operatively connected thereto in response to receipt of a first control signal and creating a negative voltage in said electrical actuation leads operatively connected thereto in response to receipt of a second control signal; and means for selectively transmitting said first and said second control signal to predetermined ones of said switch means.

Claim 7

The ink jet printhead of claim 4 wherein each of said switch means include: a first switching element having a control input operative to receive said first control signal, a voltage supply input connected to said positive voltage source, and an output connected to one of said electrical actuation leads, and a second switching element having a control input operative to receive said second control signal, a voltage supply input connected to said negative voltage source, and an output connected to said one of said electrical actuation leads.

Claim 8

The ink jet printhead of claim 5 wherein said first switching element further comprises a first transistor having a base operative to receive said first control signal, a collector connected to said positive voltage source, and an emitter connected to one of said electrical actuation leads, and said second switching element further comprises a second transistor having a base operative to receive said second control signal, a collector connected to said one of said electrical actuation leads, and an emitter connected to said negative voltage source.

Claim 9

The ink jet printhead of claim 4 wherein: each of said positive and negative voltage sources is a DC voltage source.

Claim 10

The ink jet printhead of claim 4 wherein, for each of said channels, said actuation portion partially bounding said channel comprises an opposing pair of internal sidewall sections of said body laterally bounding the channel.

Claim 11

An ink jet printhead comprising: a body having spaced series of piezoelectrically deflectable actuation portions and a front end section with a spaced series of ink discharge orifices extending rearwardly therethrough; a spaced series of enclosed ink receiving channels, each of said channels extending rearwardly through an interior of said body and opening outwardly through one of said orifices, each one of said series of channels being partially bounded by one of said series of actuation portions of said body; and drive means for actuating a selected one of said series of channels, said drive means including: means for imparting a first driving voltage having a first polarity to a selected one of said actuation portions which partially bounds said selected one of said series of channels to outwardly deflect said selected one of said actuation portions, from an initial position thereof, away from said selected one of said series of channels; means for imparting a second driving voltage having a second polarity opposite from said first polarity to said selected one of said series of actuation portions to inwardly deflect the outwardly deflected actuation portion past said initial position thereof and into said selected one of said series of channels; and means for imparting a series of driving voltage pulses of sequentially opposite polarities to outwardly deflect the inwardly deflected actuation portion to said initial position thereof.

Claim 12

An ink jet printhead comprising: a body having spaced series of piezoelectrically deflectable actuation portions and a front end section with a spaced series of ink discharge orifices extending rearwardly therethrough; a spaced series of enclosed ink receiving channels, each of said channels extending rearwardly through an interior of said body and opening outwardly through one of said orifices, each one of said series of channels being partially bounded by one of said series of actuation portions of said body; and drive means for actuating a selected one of said series of channels, said drive means including: means for imparting a first driving voltage having a first polarity to a selected one of said actuation portions which partially bounds said selected one of said series of channels to outwardly deflect said selected one of said actuation portions, from an initial position thereof, away from said selected one of said series of channels; means for imparting a second driving voltage having a second polarity opposite from said first polarity to said selected one of said series of actuation portions to inwardly deflect the outwardly deflected actuation portion past said initial position thereof and into said selected one of said series of channels; and means for imparting a series of driving voltage pulses of sequentially opposite polarities to outwardly deflect the inwardly deflected actuation portion to said initial position thereof.

Claim 13

The ink jet printhead of claim 9 wherein said drive means includes: a series of electrical actuation leads, each of said electrical actuation leads operatively connected to a different one of said series of actuation portions; a series of switch means, of each of said switch means connected to a different one of said electrical actuation leads and to positive and negative voltage sources; each of said switch means for creating a positive voltage in said electrical actuation leads operatively connected thereto in response to receipt of a first control signal and a negative voltage in said electrical actuation leads operatively connected thereto in response to receipt of a second control signal; and means for selectively transmitting said first and said second control signal to predetermined ones of said switch means.

Claim 14

The ink jet printhead of claim 10 wherein each of said switch means include: a first switching element having a control input operative to receive said first control signal, a voltage supply input connected to said positive voltage source, and an output connected to one of said electrical actuation leads, and a second switching element having a control input operative to receive said second control signal, a voltage supply input connected to said negative voltage source, and an output connected to said one of said electrical actuation leads.

Claim 15

The ink jet printhead of claim 11 wherein said first switching element further comprises a first transistor having a base operative to receive said first control signal, a collector connected to said positive voltage source, and an emitter connected to one of said electrical actuation leads, and said second switching element further comprises a second transistor having a base operative to receive said second control-signal, a collector connected to said one of said electrical actuation leads, and an emitter connected to said negative voltage source.

Claim 16

The ink let printhead of claim 10 wherein: each of said positive and negative voltage sources is a DC voltage source.

Claim 17

An ink jet printhead comprising: a body having a front end section with a spaced series of ink discharge orifices extending rearwardly therethrough, said body further having a spaced, parallel series of internal sidewall sections extending rearwardly through said body from said front section thereof and laterally bounding a spaced series of internal ink receiving channels interdigitated therewith and opening outwardly through said discharge orifices such that an opposing pair of said sidewall sections laterally bound one of said spaced series of channels, said opposing pair of said sidewall sections being piezoelectrically deflectable, from initial undeflected positions thereof, into and outwardly away from a channel which they laterally bound; and digital drive means for actuating a selected one of said channels in a manner causing a quantity of ink disposed therein to be ejected through a discharge orifice associated with said channel, said digital drive means including: means for simultaneously imposing opposite polarity DC voltages on the opposing pair of internal body sidewall sections which bound the selected channel to laterally outwardly deflect, from initial undeflected positions, the opposing pair of internal body sidewall sections which bound the selected channel; means for simultaneously reversing the polarities of the DC voltages imposed on the opposing pair of internal body sidewall sections which bound the selected channel to laterally inwardly deflect the outwardly deflected sidewall sections into the selected channel; and means for imparting a series of sequentially reversed polarity DC voltage pulses on each one of the opposing pair of internal body sidewall sections which bound the selected channel to controllably return the inwardly deflected sidewall sections to said initial undeflected positions.

Claim 18

An ink jet printhead comprising: a body having a front end section with a spaced series of ink discharge orifices extending rearwardly therethrough, said body further having a spaced, parallel series of internal sidewall sections extending rearwardly through said body from said front section thereof and laterally bounding a spaced series of internal ink receiving channels interdigitated therewith and opening outwardly through said discharge orifices such that an opposing pair of said sidewall sections laterally bound one of said spaced series of channels, said opposing pair of said sidewall sections being piezoelectrically deflectable, from initial undeflected positions thereof, into and outwardly away from a channel which they laterally bound; and digital drive means for actuating a selected one of said channels in a manner causing a quantity of ink disposed therein to be ejected through a discharge orifice associated with said channel, said digital drive means including: means for simultaneously imposing opposite polarity DC voltages on the opposing pair of internal body sidewall sections which bound the selected channel to laterally outwardly deflect, from initial undeflected positions, the opposing pair of internal body sidewall sections which bound the selected channel; means for simultaneously reversing the polarities of the DC voltages imposed on the opposing pair of internal body sidewall sections which bound the selected channel to laterally inwardly deflect the outwardly deflected sidewall sections into the selected channel; and means for imparting a series of sequentially reversed polarity DC voltage pulses on each one of the opposing pair of internal body sidewall sections which bound the selected channel to controllably return the inwardly deflected sidewall sections to said initial undeflected positions.

Claim 19

The ink jet printhead of claim 14 wherein said digital drive means includes: a series of electrical actuation leads, each of said electrical actuation leads operatively connected to a different one of said internal sidewall sections; a series of switch means, each of said switch means connected to a different one of said electrical actuation leads and to positive and negative voltage sources; each of said switch means for creating a positive voltage in said electrical actuation leads operatively connected thereto in response to receipt of a first control signal and creating a negative voltage in said electrical actuation leads operatively connected thereto in response to receipt of a second control signal; and means for selectively transmitting said first and said second control signal to predetermined ones of said switch means.

Claim 20

The ink jet printhead of claim 15 wherein each of said switch means include: a first switching element having a control input operative to receive said first control signal, a voltage supply input connected to said positive voltage source, and an output connected to one of said electrical actuation leads, and a second switching element having a control input operative to receive said second control signal, a voltage supply input connected to said negative voltage source, and an output connected to said one of said electrical actuation leads.

Claim 21

The ink jet printhead of claim 16 wherein said first switching element further comprises a first transistor having a base operative to receive said first control signal, a collector connected to said positive voltage source, and an emitter connected to one of said electrical actuation leads, and said second switching element further comprises a second transistor having a base operative to receive said second control signal, a collector connected to said one of said electrical actuation leads, and an emitter connected to said negative voltage source. PG,22

Claim 22

The ink jet printhead of claim 15 wherein: each of said sidewall sections has a first portion connected to ground, and a second portion spaced apart from said first portion in a direction transverse to a length of said channels, and said electrical actuation leads are connected to said second portion of said sidewall sections.