WO1999010178A1

WO1999010178A1 - Non-resonant burst mode operation of drop on demand ink jet printer

Info

Publication number: WO1999010178A1
Application number: PCT/US1998/017401
Authority: WO
Inventors: Deane Gardner
Original assignee: Topaz Technologies, Inc.
Priority date: 1997-08-29
Filing date: 1998-08-20
Publication date: 1999-03-04
Also published as: TW422787B; AU9029798A

Abstract

A waveform for driving a piezoelectric element comprises a plurality of signals at least one of which comprises a first portion and a second portion, wherein the first portion comprises energy that operates the piezoelectric element and the second portion comprises energy that counteracts energy induced by the first portion, and wherein each other signal of the plurality of signals comprises a first portion only.

Description

DESCRIPTION

NON-RESONANT BURST MODE OPERATION OF DROP ON DEMAND INK JET PRINTER

Background of the Invention 1. Field of the Invention

The present invention pertains to the field of ink jet printers, and more specifically, to drop-on-demand piezoelectric ink jet printers. 2. Description of Related Art

Drop-on-demand ink jet printers having piezoelectric components are well known in the art. In general, piezoelectric drop-on-demand ink jet printers are constructed with a piezoelectric transducer component which reacts to the application of an electrical drive signal with a mechanical movement or distortion such that a drop of ink is expelled from a print head ink channel or cavity that is in mechanical communication with the transducer component.

Various methods for operating variable volume drop-on demand ink jet printers have been described. Two methods used for operating drop on demand ink jet printers include single-cycle operation with drive pulse amplitude and/or pulse width modulation and multi-cycle operation where multiple pulses are used to actuate the piezoelectric components in a single cycle.

A disadvantage of using single cycle operation is that such systems generally have a limited droplet volume modulation range and an ejected droplet speed which varies with droplet volume. For example, U.S. Patent No. 5,461,403 discloses that in single cycle mode operation, as the volume of the droplet ejected increases the speed at which the droplet strikes the media decreases. Experience has shown that this causes poor quality images to be reproduced.

In prior art systems utilizing multi-cycle mode operation, a train of drive pulses, i.e., a burst series is used to drive a print head at or near the resonant frequency of the ink channel or nozzle, see for example, U.S. Patent Nos. 4,513,299 and 5,381,084. In such systems, the drop volumes and speeds are highly dependent on both the tuning of the pulse width, the frequency of the train of pulses with respect to the resonant frequency of the ink filled piezoelectric transducer, and the damping factor (Q) of the transducer and ink combination. When the pulses are not properly tuned, when the resonant frequency used to calculate the size or shape of the pulses is not precise, and/or when the damping factor varies during operation, the speed and volume of the expelled droplets will vary. This will- cause printing inconsistencies and/or printer failure. Printing inconsistencies can include ink splattering which makes it very difficult to print fine lines on the print medium. Print failure can occur because improper or imprecise pulses can cause air to be ingested into the ink chamber, thereby increasing transducer wear and ultimately leading to transducer failure.

Multi-cycle burst series are depicted in Fig. 1A & Fig. IB. In Fig. 1 A, a series of pulses are used to drive a transducer, the pulses are fixed in terms of magnitude and pulse width. A different type of multi-cycle burst series is shown in Fig. IB. In the burst series shown in Fig. IB, the pulse width and amplitude of each of the pulses vary. In each of Figs. 1 A and IB, the multi-cycle burst series is used to create a delivered droplet volume that is a combination of several smaller droplets. In other words, a macro-droplet is created by combining a plurality of smaller micro-droplets.

When an ink jet transducer is operated at or near its resonant frequency, the resonant damping factor becomes difficult to predict. This makes it difficult to control the amount of energy built up in the channel during the burst series. The result of not being able to determine the energy built up in the ink channel is that the ejected droplet velocity will have two components; one component is a result of the current drive pulse; the second component is the built up energy in the channel. The actual velocity of the pulses will be a combination of the energy imparted by the current drive pulse and the residual energy that remains from prior pulses in the multi-cycle burst series. Since the energy built up in the channel is difficult to determine problems in precise printing result due to the movement of the printhead at a constant rate over the media which will not place the droplet at the desired location and the possible air ingestion from too much energy.

A method for removing built up energy involves the use of cancellation pulses. A cancellation pulse is used to dissipate the residual energy in the ink channel built up by a drive signal. In the prior art cancellation pulses are fired after a single pulse in single cycle operation or after all the pulses in cycle burst operation, as shown in Fig. 2. A prior art cancellation pulse in a system utilizing pulses at resonant frequency is disclosed in U.S. Patent No. 4,972,211, which shows the use of a cancellation pulse to expand the channel at a time 4L/C after the first driving pulse (where L is the length of the channel and C is the speed of sound in the channel). However, the amplitude and pulse- width of the cancellation pulse is a function of ink viscosity, head structure, and the voltage and pulse width of the particular drive pulse. Additionally, when operating at the resonant frequency, the resonant damping factor (Q) of the system needs to be factored into the creation of the cancellation pulse or pulses. Therefore, a system that can dissipate built up energy in a printhead ink channel which is operating using multi-cycle burst series mode is desired.

It is also desirable to create a multi-cycle burst series waveform that is not dependent on the resonance characteristics of the transducer and/or ink viscosity.

It is additionally desired to create a drive pulse which minimizes the resonant interference created in an ink channel due to a prior drive pulse in the same multi-cycle burst series.

It is further desired to create a system whereby the delay between each multi-cycle burst series is reduced, allowing higher resolution and faster printing speeds.

Summary of The Inventions

A waveform for driving a piezoelectric element comprises a plurality of signals at least one of which comprises a first portion and a second portion, wherein the first portion comprises energy that operates the piezoelectric element and the second portion comprises energy that counteracts energy induced by the first portion, and wherein each other signal of the plurality of signals comprises a first portion.

In another embodiment a waveform for driving a piezoelectrical element comprises a plurality of signals each signal being out of phase with a prior signal in the multi-burst series waveform.

In yet another embodiment the present invention is directed toward a method for driving a drop on demand ink jet transducer comprising transmitting a first drive pulse to the transducer, outputting a cancellation pulse to the transducer, and transmitting a second drive pulse to said transducer after transmitting the cancellation pulse, wherein the first drive pulse and the second drive pulse are part of a multi-cycle burst series waveform comprising at least two pulses.

These and other aspects of the present invention are described more fully in the following specification and illustrated in the accompanying drawing figures.

Brief Description of the Drawings

Fig. 1A and IB depict prior art multi-burst series mode driving waveforms. Fig. 2 depicts a prior art drive and cancellation pulse waveform.

Fig. 3 is a functional block diagram of a signal generator according to an embodiment of the present invention.

Fig. 4 is a multi-cycle burst series waveform according to a preferred embodiment of the present invention. Fig. 5 depicts an alternate embodiment of a waveform generator in which cancellation pulses are generated.

Fig. 6 depicts a drive waveform including cancellation pulses according to a preferred embodiment of the present invention.

Fig. 7 is a graphical illustration of a comparison of residual pressure in a channel while operating in a resonant burst, non-resonant burst mode according to one embodiment of the present invention and while operating in a non-resonant burst mode with cancellation pulses according to another embodiment of the present invention.

Description Of The Preferred Embodiments

Fig. 3 is a functional block diagram showing the principal components of a preferred signal generator of the present invention. The signal generator generates and transmits the electrical drive signal which drives the transducer material in the ink jet print head. A preferred ink jet transducer and ink channel for use with the present invention are described in copending U.S. Patent Application Serial No. 08/808,608, the specific details of which are hereby incorporated by reference in their entirety. The operational sequence of signal generator begins with the application of a waveform control signal 130 to a print head controller (also called burst series waveform generator) 134 from an outside signal source. Waveform control signals 130 may also be sent from an external encoder or microprocessor. The optional microprocessor or encoder outputs control signals linked to the motion of the print head so that the expelled ink drops are ejected with the optimal timing for impacting the print medium at the correct position for precise printing. The burst series waveform generator 134 produces burst series waveform 136, comprising one or more pulses per burst series, which is applied to an amplifier 138. The amplifier 138 increases the amplitude of the burst series waveform 136 to an appropriate voltage level to drive the transducer 141 in the print head. The amplified burst waveform 139 from the amplifier 138 is in communication with a switch array 140. Switch array 140 comprises a series of conventional digitally controlled switches (not shown). Switch arrays 140 selectively control which individual channels of the array of print head channels will be permitted to receive the actuating amplified burst series waveform 139. The amplified burst series waveform 139 is then applied to selected channels of the print head transducer 141.

The preferred burst series waveform generator 134 comprises a lookup table controller 150. Look up table controller 150 directs the operation of a lookup table 152. Lookup table controller 150 receives waveform control signals 130 from the outside signal source (not shown). The outside signal source transmits waveform control signals 130 pertaining to the timing and waveform parameters of the burst series waveform to be generated by the burst signal waveform generator 134. Exemplary parameters that may be specified by the waveform control signal 130 include the frequency of the waveform, the number of pulses within a burst series, and the shape of the waveform. Lookup table 152 is programmed with a table of waveform-data points which define electrical burst series waveforms that can be utilized to drive the print head transducers 141. In the preferred embodiment, the burst series waveform is defined by a series of (x,y) coordinate points, where the x-coordinate represents a point in time on a burst series waveform plot, and the y-coordinate represents the voltage or amplitude of the waveform at that particular x-coordinate. Each individual waveform-data point in the lookup table 152 corresponds to a (x,y) coordinate location on a desired waveform. For each burst series, the lookup table controller 150 outputs a stream of time-factor coordinates (x-coordinates) to the lookup table 152, and the lookup table 152 in turn outputs a series of amplitude values (y-coordinates) corresponding to each x-coordinate. The lookup table controller 150 contains a counter which increments through the lookup table's input range at a rate determined by the specific contents of the waveform control signal 130. The waveform-data points from the lookup table 152 are applied in sequence to a digital-to-analog converter ("DAC") 154, which outputs an analog burst series waveform 136 that corresponds to the series of (x,y) coordinate points, and which is a low power version of the signal that will be applied to transducer 141 of the print head. Other DACs may also receive control inputs signals which partially determine several parameters of the burst series waveform 136. For example, a separate DAC may be employed to control the overall amplitude of the output burst series waveform.

The function of the switch array 140 is to selectively allow the amplified burst series waveform to fire only certain ink channels of the print head 141. In the preferred embodiment, switch array 140 generally comprises an array of switches, e.g., field effect transistors, which are controlled to selectively allow the amplified burst series waveform(s) to pass only to certain ink channels of the print head 141. The presently preferred embodiment also employs an opto-isolator 144 to apply switch control signals 146 from the print head controller 132 to the switch array 142. This reduces switch cost by allowing the use of single transistor switches. The print head controller 132 provides switch control signals 146 that control whether a given channel of the print head is or is not printing at a given point in time as the print head 141 is moved across the print medium.

Referring to Fig. 4, multi-cycle burst series 200 includes drive pulses 205, 206, 207, 208, 209 and 210. Each drive pulse is used to cause a different transducer in an ink channel to expand, then contract, thereby causing a droplet to be expelled from the nozzle. In this embodiment, each drive pulse is depicted as having approximately the same amplitude and width. However, it should be understood that the individual pulses in a given multi-cycle burst series can vary in amplitude and pulse width depending on the pattern that is output from the look up table controller. Further, the time between pulses may be varied as desired. Additionally, the number of drive pulses 205-210 is variable according to the desired volume of the droplet to be ejected onto the media.

In a presently preferred embodiment, the period of each drive pulse 205-210 of the multi-cycle waveform 200 is of a time period longer than the resonant time period, 4L/C, of the ink channel and transducer combination. Preferably, the time period is 6L/C. (Where L is the length of the ink channel and C is the speed of sound in the channel.) By ^~ having a period of 6L/C, energy resonating in the transducer channel is 180 degrees out phase with the next drive pulse. The 180 degree phase difference between drive pulses allows for dissipation of the energy built up in the channel through phase cancellation. That is, the drive pulse is timed to correspond with the time the pressure wave that resulted from the prior drive pulse has been reflected and is located at a position approximately equal to half the distance between transducer and the wall of the ink channel opposing the nozzle. Therefore, the next drive pulse will work to decrease the magnitude of the combined pressure wave that exists in the ink channel. Timing the drive pulses to be 180 degrees out of phase acts as an anti-resonance condition for the ink channel, which allows energy built up within the channel to dissipate without the application of cancellation pulses. The shape, amplitude and number of pulses of a particular burst series described above is by way of example only. Other shapes, amplitudes and number of pulses are useable with the present invention without departing from its scope. Examples of shapes, amplitudes and number of pulses which may be transmitted in a particular burst series are disclosed in copending U.S. Patent Application Serial No. 08/808,608, the specific details of which are incorporated herein by reference in its entirety.

An ink jet printing system operating according to a preferred embodiment as described with respect to Fig. 4 above, decreases the built up energy remaining in the ink channel. The reduction of built up energy allows for a significant decrease in the time delay 250 which would otherwise be required to be present between successive multi-cycle burst series of signals, since a decreased energy dissipation time is required to dissipate a lower built up energy.

A cancellation pulse generated in accordance with the present invention, when applied to a print head transducer, generates counter-pressure waves which substantially cancel the residual pressure waves present in the ink channels. To be effective, a cancellation pulse must produce a counter-pressure wave which is substantially at the same absolute energy level as the existing residual pressure wave in the ink channel, but which is out of phase when compared to the phase of the existing residual pressure wave. This counter-pressure wave is preferably generated by a calculated pulse of the same general type and shape but having a different amplitude from the drive pulse which was used to fire the ink channel in question.

Fig. 5 shows an embodiment of a waveform generator 160 which can be utilized to generate cancellation pulses in accordance with the present invention. The waveform generator 160 contains a lookup table controller 162 which transmit control signals to both a burst series lookup table 164 and a cancellation pulse lookup table 166. Burst series lookup table 164, like the lookup table 152 of Fig. 3, is preferably programmed with a table of waveform coordinate points that define one or more burst series signal waveforms which can be utilized to drive the print head transducers 141 to controllably eject droplets of ink from the print head. Cancellation pulse lookup table 166 is preferably programmed with a table of waveform coordinate points which define a set of one or more cancellation pulse waveforms optimized for canceling residual pressure waves created from the waveforms programmed into the burst series lookup table 164.

In the preferred embodiment, lookup table controller 162 comprises a counter which increments and outputs a set of time factor coordinates (x-coordinates) to the burst series lookup table 164. In response to the signal applied from the lookup table controller 162, the burst series lookup table 164 transmits a series of voltage amplitude coordinates

(y-coordinates), which has a corresponding time factor on the x-coordinate. Together, the x and y components define a desired burst series waveform. This output is applied to a digital-to-analog converter ("DAC") 168 to generate an analog burst series waveform. The firing of a given pulse sets timer 167 to 1 and starts the timer 167. Timer 167 is employed to track the total elapsed time which elapsed since the firing of the drive pulse. After a designated period of time, the timer 167 triggers the lookup table controller 162, which increments and outputs a set of cancellation pulse time factor coordinates (x-coordinates) to the cancellation pulse lookup table 166. The cancellation pulse lookup table 166 produces a voltage amplitude (y-coordinates), which correspond to the x-coordinate. Together the x and y coordinate define the cancellation pulse which is appropriate to generate counter-pressure waves to cancel the residual pressure wave in the ink channel created by the most recent drive pulse. The output of the cancellation pulse lookup table 166 is then applied to the DAC 168 to produce an analog cancellation pulse. This process is then repeated for some and preferably all of the drive pulses in a multi-cycle burst series. An alternate embodiment comprises the triggering of the cancellation pulse immediately after the firing of the drive pulse. In this embodiment, a timer 167 is not required, as the lookup table controller 162 is programmed to immediately begin transmitting a control signal to the cancellation pulse lookup table 166 immediately following the transmission of a control signal to the burst series lookup table 164. Yet another embodiment triggers the cancellation pulse after a fixed time delay following the end of the previous drive pulse.

The cancellation pulse coordinate values within the cancellation pulse lookup table 166 can be generated in a plurality of ways. For example, the lookup table values can be derived empirically, by repeatedly firing a drive pulse and a corresponding "test" cancellation pulse through the transducer of a given ink channel. By incrementally adjusting the amplitude and phase parameters of the sample cancellation pulses which are fired, a set of appropriate cancellation pulse parameters can be plotted which correspond to the preprogrammed set of burst series pulses which are used to drive the ink jet print head. The preferred value of the cancellation pulse generally corresponds to the experimental firings.

Alternatively, the lookup table values can be obtained by simulating the pressure wave effects resulting from the firing of a given drive pulse in an ink channel, and mathematically calculating the parameters of a cancellation pulse signal to generate appropriate counter-pressure wave. The simulation can be performed by an onboard processor within the printing apparatus or a computer that is used to operate the printing apparatus. This simulation determines the amplitude and timing of a pulse of a burst series which minimizes or cancels the residual pressure wave at a certain time period after the firing of a previous drive pulse. The character of the cancellation pulse required is related both to the amplitude and phase of the pressure wave present in the ink channel and to the particular geometry and characteristics of the ink channel. The cancellation pulse for the preferred embodiment is preferably a half pulse of a sinusoidal wave displaced in time from the type of drive pulse used to fire an ink droplet. Various simulations may be performed to determine the optimal characteristics and parameters of the desired cancellation pulse. The effectiveness of the cancellation pulses can be experimentally confirmed, preferably in conjunction with the repetition rate method described above, as is later described with respect to Fig. 7.

Referring to Fig. 6, multi-cycle burst series 300 is made up of pulses 305, 306, 307, 308, 309, and 310. In a preferred embodiment, each pulse 305, 306, 307, 308, 309, and 310, includes a drive pulse component 330 and a cancellation pulse component 340. However, it is also possible to have a multi-cycle burst series where only one or less than all of the pulses 305-310 comprise a drive pulse component 330 and cancellation pulse component 340, while the other pulses comprise a drive 305-310 in the multi-burst series 300 pulse component 330 with a cancellation pulse component 340. The cancellation pulse component 340 preferably is out of phase with the drive pulse component 330. In a preferred embodiment, the shape of drive pulse component 330 is sinusoidal or trapezoidal, however, any other pulse shape which can be created using the apparatus described with respect to Fig. 3. The period of the cancellation pulse component 340 is preferably one-half the period of the drive pulse component, preferably 2L/C. Overall, each pulse 305-310 of multi-cycle burst series has a period approximately equal to 6L/C. The timing of the drive pulses also acts to cancel out any residual built up pressure in the ink channel not eliminated by the cancellation pulses in the same way as described with respect to Fig. 4.

Just as the pulses 305, 306, 307, 308, 309 and 310 act on the ink jet transducer 141 in continuous sequence, the energy supplied by each of the pulses 305, 306, 307, 308, 309 and 310 to the ink channel is removed by the cancellation pulse. Any residual energy in the ink channel not dissipated by the cancellation pulse is largely anti-phase (180 degrees out of phase) to the next drive pulse, thereby greatly minimizing the residual energy build up during the multi-cycle burst series. This makes the energy build up in the ink channel self limiting and largely independent of changes in ink viscosity or other factors which effect the resonant damping factor (Q) of the ink channel and transducer combination. In the embodiment of a multi-cycle burst series shown in Fig. 6, the amplitude of cancellation pulse 340 is related to that of drive pulse 330 by a scalar constant. The scalar constant is a function of the ink viscosity and the ink channel construction. For example, as the ink channel volume and ink viscosity increase, the scalar constant would decrease. In other words, the relative magnitude of the cancellation pulse component 340 will increase with respect to drive pulse component 330. Yet another advantage of using a cancellation pulse component 340 after each drive pulse component 330, is the reduction of air ingestion into the ink channel because the reflected pressure waves form the drive pulses are canceled and do not create an additive pressure wave which acts to increase the ink channel volume and pull air in through the nozzle orifice of the ink channel. A further advantage of using an embodiment of a multi-cycle burst series waveform according to embodiments of the present invention (see Fig. 4 and Fig. 6), is that a reduced wait period 250 is required between consecutive multi-cycle burst series. This is because the pressure build up in the ink channel is dissipated between individual drive pulses and not between each multi-cycle burst series. This advantage can be seen with respect to Fig. 7, which is a graphical representation of the pressure build up in an ink channel using various methods of multi-cycle burst series is depicted. The y-axis represents a multiple of the initial pressure in the ink channel that results from an input pulse. The x-axis represents the order of the pulse in the multi-cycle burst series. As can be seen by curve 400, the residual energy build up that results from multi-cycle burst series at the resonant frequency rises to a level of over 80% of the pulse magnitude after the second pulse using a multi-burst cycle with pulses at the resonant frequency. In contrast, the use of cancellation pulse component 340 immediately after a drive pulse component 330, as described with respect to Fig. 6, reduces the residual energy by a factor of 6 that is seen on curve 420. The use of a multi-cycle burst series having drive pulses as described with respect to Fig. 4, reduces the residual pressure build up in the ink channel by half, even without the use of cancellation pulse. This is depicted by curve 410. Therefore, it can be seen that the present invention greatly reduces the built up pressure in the ink channel which results in an improvement of the droplet volume and droplet velocity leading to more accurate printing. While the embodiments, applications and advantages of the present invention have been depicted and described, there are many more embodiments, applications and advantages possible without deviating from the spirit of the inventive concepts described herein. The invention should therefore should only be restricted in accordance with the spirit of the claims appended hereto and is not restricted by the preferred embodiments, specification or drawings.

Claims

What is claimed is:

1. A waveform for driving a piezoelectric element comprising a plurality of signals at least one of which comprises a first portion and a second portion, wherein said first portion comprises energy that operates said piezoelectric element and said second portion comprises energy that counteracts energy induced by said first portion and each other signal of said plurality of signals comprises a first portion.

2. The waveform of claim 1 , wherein each signal of said plurality of signals excites the transducer channel out of phase with a residual pressure wave created in an ink channel housing, said piezoelectric element due to prior signal of said plurality of signals.

3. The waveform of claim 2, wherein a time between each signal of said plurality of signals is approximately 6L/C later than a prior signal of said plurality of signals.

4. The waveform of claim 1 , wherein a magnitude of each second portion is a scalar multiple of a magnitude of each first portion.

5. The waveform of claim 1 , further comprising an ink channel having ink therein and said transducer actuates to decrease a volume of said ink channel and wherein the time of said first portion and second portion in combination is greater than a resonant time period of said ink channel.

6. A waveform for driving a piezoelectrical element comprising a plurality of signals each signal being out of phase with a residual pressure wave created by a prior signal of said plurality of signals.

7. The waveform of claim 6, wherein each signal is substantially 180 degrees out of phase with said residual pressure wave.

8. The waveform of claim 6, further comprising an ink channel having ink therein and said transducer actuates to decrease a volume of said ink channel and wherein the time of each signal is greater than a resonant time period of said ink channel.

9. A method for driving a drop on demand ink jet transducer, comprising the steps of: transmitting a first drive pulse to the transducer, transmitting a cancellation pulse to the transducer, and transmitting a second drive pulse to the transducer after transmitting the cancellation pulse, wherein the first drive pulse and the second drive pulse are part of a waveform comprising at least two pulses.

10. The method of claim 9 wherein said second drive pulse occurs at a time approximately equal to 6L/C greater than said first pulse.

WO 99/10178 . _<- PCT/US98/17401

AMENDED CLAIMS

[received by the International Bureau on 25 January 1999 (25.01.99); original claims 1-2 and 6-9 amended; new claims 11-15 added; remaining claims unchanged (3 pages)]

1. A waveform for driving a piezoelectric element comprising a plurality of signals, at least one of which comprises a first portion and a second portion, wherein said first portion induces energy that operates said piezoelectric element and said second portion induces energy that counteracts energy induced by said first portion and each preceding signal of said plurality of signals.

2. The waveform of claim 1, wherein each signal of said plurality of signals excites the transducer channel out of phase with a residual pressure wave created in an ink channel housing, due to prior signal of said plurality of signals.

6. A waveform for driving a piezoelectrical element, said piezoelectrical element comprising at least one ink channel, said waveform comprising a plurality of signals, each of said plurality of signals leaving a residual pressure wave in said ink channel that is out of phase with a residual pressure wave created by a preceding one of said plurality of signals.

7. The waveform of claim 6, wherein each successive residual pressure wave is substantially 180 degrees out of phase with each immediately preceding residual pressure wave.

8. The waveform of claim 6 wherein said transducer actuates to decrease a volume of said ink channel and wherein the time of each signal is greater than a resonant time period of said ink channel.

9. A method for driving a drop on demand ink jet transducer, comprising the steps of: transmitting a first drive pulse to the transducer, transmitting a cancellation pulse to the transducer, and transmitting a second drive pulse to the transducer immediately after transmitting the cancellation pulse, wherein the first drive pulse and the second drive pulse are part of a waveform comprising at least two pulses.

11. A waveform for driving a piezoelectric element comprising a plurality of signals wherein each of said plurality of signals comprises a first portion and a second portion, wherein said first portion induces energy that operates said piezoelectric element and said second portion induces energy that counteracts energy induced by said first portion and each preceding signal of said plurality of signals and wherein there is no time intervening between successive ones of said plurality of signals.

12. The waveform of claim 11, wherein each signal of said plurality of signals excites the transducer channel out of phase with a residual pressure wave created in an ink channel housing, due to prior signal of said plurality of signals.

13. The waveform of claim 12, wherein a time between each signal of said plurality of signals is approximately 6L/C later than a prior signal of said plurality of signals.

14. The waveform of claim 11 , wherein a magnitude of each second portion is a scalar multiple of a magnitude of each first portion.

15. The waveform of claim 1, further comprising an ink channel having ink therein and said transducer actuates to decrease a volume of said ink channel and wherein the time of said first portion and second portion in combination is greater than a resonant time period of said ink channel.