Patent Publication Number: US-11660861-B2

Title: Systems and methods for controlling operation of micro-valves for use in jetting assemblies

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority to and benefit of U.S. Non-Provisional patent application Ser. No. 16/407,487 filed May 9, 2019, now U.S. Pat. No. 10,994,535, which claims priority to and benefit of U.S. Provisional Application No. 62/670,306 filed May 11, 2018, and U.S. Provisional Application No. 62/712,052, filed Jul. 30, 2018, the disclosures of which are each incorporated by reference herein in their entirety. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates generally to the field of micro-valves fabricated using micro-electro-mechanical systems (MEMS) techniques. More specifically, the present disclosure relates to jetting assemblies including micro-valves that are used for industrial marking and coding. 
     BACKGROUND 
     Conventional printing technologies have several shortcomings. For example, continuous inkjet printers have certain deficiencies that are difficult to eliminate. The process of generating droplets from an ink supply, for example, may lead to ink dripping in an undesired direction (e.g., away from a target), leading to maintenance requirements. Additionally, makeup fluid is lost over time as a result of evaporation, requiring continuous replenishment. Other maintenance costs, such as repairing orifice plates due to degradation, are also required. 
     SUMMARY 
     One embodiment relates to a marking system. The marking system includes a valve body including an orifice plate including at least one orificee extending therethrough and at least one micro-valve. Each of the at least one micro-valve includes an actuating beam movable from a closed position in which a corresponding one of the orifices is sealed by a portion of the actuating beam such that the micro-valve is closed, wherein the actuating beam is movable from the closed position into a peak position in response to application of a control signal thereto. The marking system also includes a controller electrically connected to the actuating beams. The controller is configured to generate a control signal for each of the actuating beams, wherein each control signal includes a drive pulse having a predetermined voltage, wherein, in response to the drive pulse, the actuating beam oscillates such that the actuating beam moves from the closed position to a peak position in which the corresponding orifice is open and returns to the closed position in a characteristic period, wherein the drive pulse has a duration that substantially corresponds to the characteristic period such that the actuating beam is in the closed position after the drive pulse is complete. 
     Another embodiment relates to a method of calibrating a marking system including at least one actuating beam. The method includes applying, by a controller electrically connected to an actuating beam of a micro-valve, a drive pulse to the actuating beam, the drive pulse having a predetermined voltage configured to induce an oscillation of the actuating beam. The calibration method also includes determining an oscillation period of a natural frequency of the actuating beam, the oscillation period including an interval between successive times in which the actuating beam is in a closed position where the actuating beam seals an orifice in an orifice plate on which the actuating beam is disposed such that the micro-valve is closed. The method also includes determining a drive pulse ON time based on the oscillation period. The method also includes setting a drive waveform for the actuating beam, the drive waveform comprising a biasing portion in which the control signal increases from zero volts to a bias voltage, a voltage upswing portion in which a control signal voltage rises from the bias voltage to the predetermined voltage, a driving portion where the control signal voltage is at the predetermined voltage for the drive pulse ON time, and a voltage downswing portion in which the control signal voltage falls from the predetermined voltage to the bias voltage or zero. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure will become more fully understood from the following detailed description, taken in conjunction with the accompanying figures, in which: 
         FIG.  1    is a perspective of a jetting assembly disposed in a holder, according to an example embodiment. 
         FIG.  2    is an exploded view of the jetting assembly shown in  FIG.  1   . 
         FIG.  3    is a schematic cross-sectional view of the jetting assembly shown in  FIG.  1   . 
         FIG.  4 A  is a plan view of the jetting assembly shown in  FIG.  1   ;  FIG.  4 B  is a schematic illustration of an adhesive structure that may be used in the jetting assembly of  FIG.  1   , according to an example embodiment. 
         FIG.  5 A  is a-cross sectional view of a jetting assembly including a micro-valve, according to an example embodiment. 
         FIG.  5 B  is a-cross sectional view of a jetting assembly including a micro-valve, according to another example embodiment. 
         FIG.  6    is cross-sectional view providing a more detailed view of the jetting assembly shown in  FIG.  5 A . 
         FIG.  7 A  is a cross-sectional view of an actuating beam of a micro-valve, according to an example embodiment;  FIG.  7 B  is a front cross-sectional view of the actuating beam of  FIG.  7 A , according to another example embodiment. 
         FIG.  8    is a block diagram of a marking system including a jetting assembly, according to an example embodiment 
         FIG.  9    is a chart depicting the displacement of an actuating beam in response to application of a control signal, according to an example embodiment. 
         FIG.  10 - 16    shows positions of an actuating beam at various points in time during application of a control signal thereto, according to an example embodiment. 
         FIG.  17    is a chart depicting the displacement of an actuating beam in response to application of various drive waveforms, according to an example embodiment. 
         FIGS.  18 ,  19 ,  20 ,  21  and  22    are charts showing various drive waveforms for driving an actuating beam of a micro-valve, according to an example embodiment. 
         FIG.  23    is a flow diagram of a method of calibrating an actuating beam of a micro-valve, according to an example embodiment. 
         FIG.  24    shows a cross-sectional view of a jetting assembly  2400 , according to an example embodiment. 
         FIG.  25    is a flow diagram of a method  2500  of checking a jetting assembly for faults is shown, according to an example embodiment. 
         FIG.  26    is a plot showing a drive waveform for driving an actuating beam of a micro-valve, according to an example embodiment. 
         FIG.  27    are plots showing motion of an actuating beam of a micro-valve in response to a trapezoidal drive waveform, and the drive waveform of  FIG.  26   . 
         FIG.  28    are plots showing motion of an actuating beam of a micro-valve in response to the drive waveform of  FIG.  26    including a hold portion having hold times of 10 μseconds, 25 μseconds, 50 μseconds and 100 μseconds. 
         FIG.  29    is a plot of weight of a droplet of fluid ejected from a corresponding orifice of the micro-valve in response to the beam motions shown in  FIG.  28   . 
         FIG.  30    is a schematic flow diagram of a method for driving an actuating beam of a micro-valve, according to an example embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Before turning to the figures, which illustrate the exemplary embodiments in detail, it should be understood that the present application is not limited to the details or methodology set forth in the description or illustrated in the figures. It should also be understood that the terminology is for the purpose of description only and should not be regarded as limiting. 
     Referring generally to the figures, described herein is a jetting assembly including multiple micro-valves. The micro-valves described herein employ an actuating beam having a sealing member disposed thereon. The utilization of such an actuating beam enables tailoring the micro-valve to eliminate or reduce various deficiencies associated with conventional technologies including continuous inkjet jetting assemblies. For example, in various embodiments, the micro-valve includes a spacing member disposed between the actuating beam and an orifice plate. The spacing member maintains a spacing of a first end of the actuating beam and an orifice within the orifice plate so as to prevent squeeze film damping of the actuating beam. The actuating beam extends over the orifice from the spacing member and a sealing member extends towards the orifice to form a seal at the orifice. Thus, without application of any electrical energy to the actuating beam, the sealing member seals off the orifice plate. In other words, the default position of the actuating beam (e.g., configured by careful selection of the materials contained therein) is that the micro-valve is closed. As such, fluid (e.g., ink, solvent, etc.) disposed in the micro-valve is sealed off from the external environment of the jetting assembly. This eliminates evaporation of the fluid, which reduces clogs. Additionally, the limited evaporation enables faster-drying ink to be used, which allows for printing at higher speeds than conventional systems. 
     To mitigate against fluid leaks, the micro-valves described herein include a sealing structure configured to form a seal that separates the orifice from a volume proximate to the actuating beam when the actuating beam is in its default position. The sealing structure may include any combination of a plurality of components designed to ensure the formation of the seal. For example, in various embodiments, the sealing structure includes a valve seat disposed on the orifice plate proximate to the orifice. The valve seat may surround the orifice and define an opening that overlaps with the orifice to define a fluid outlet. The sealing member may contact the valve seat with the actuating beam in the default position. In some embodiments, the valve seat is constructed of a compliant material to facilitate the formation of an enhanced seal resulting from pressure applied due to curvature of the actuating beam. 
     In another aspect, the sealing structure may include components attached to or extending from the sealing member. For example, in one embodiment, the sealing structure includes a compliant structure extending from an orifice-facing surface of the sealing member. The compliant structure may include a narrow portion and a wider portion having a cross-sectional area greater than that of the orifice. As a result, the actuating beam compresses the compliant structure towards the orifice plate to facilitate the formation of the seal. Alternatively, or additionally, the sealing structure may include a sealing blade extending from the orifice-facing surface to contact the valve seat or orifice plate. The sealing blade further facilitates the formation of the seal due to the pressure resulting from its relatively small cross-sectional area, which focuses downward pressure applied via the actuating beam to a point to form a tight seal. Thus, the various structures described herein enhance the seals formed when the actuating beam is in its default position. 
     In some arrangements, a drive pulse including a drive waveform may be used to move the actuating beam from a closed position (e.g., the default position) tin which the orifice is sealed and thereby, the micro-valve is closed to an open or peak position away from the orifice. The drive waveform may be configured to maintain the actuating beam in the open position until a desired amount of fluid has been ejected from the orifice. However, some drive pulses may cause the actuating beam to move beyond the peak position, for example, due to an inherent bias (e.g., tension) in the actuating beam. In such scenarios, the actuating beam may recoil towards the orifice and may continue to vibrate until the fluid contained within the micro-valve damps the vibration of the actuating beam. The recoil may cause splatter or interruption in fluid ejection which is undesirable. 
     Embodiments described herein provide for drive pulses including drive waveforms which may provide benefits including, for example, (1) preventing overshoot of an actuating beam beyond a peak position when moving from a closed position to a peak or open position; (2) limiting recoil and thereby, vibration of the actuating beam on reaching the peak position; and (3) preventing splatter and/or an inaccurate volume in a droplet of a fluid ejected from an orifice of a micro-valve including the actuating beam when the actuating beam is in the open position. 
     As described herein, the term “default position,” when used in describing an actuating beam of a micro-valve, describes the position of the actuating beam with respect to various other components of the micro-valve without application of any control signals (e.g., an electrical charge, current or voltage) to the actuating beam. In other words, the default position is the position of the actuating beam (and any components attached thereto) when the actuating beam is in a passive state. It should be appreciated that other embodiments are envisioned in which the default position is an open position of the actuating beam. 
     Referring now to  FIG.  1   , a perspective view of a jetting assembly  100  disposed in a holder  150  is shown, according to an example embodiment. Jetting assembly  100  includes a valve body  102  attached to a carrier  108 . The holder  150  may include a substantially circular-shaped body having an opening contained therein adapted to receive the jetting assembly  100 . Holder  150 &#39;s body may include notches  118  extending from a peripheral edge thereof to facilitate attachment of the holder  150  to a marking device. The valve body  102  may be a component of a marking device. In an exemplary embodiment, the valve body  102  is used in an industrial marking device including a pressurized fluid (e.g., ink) supply. In other embodiments, the valve body  102  or any of the micro-valves described herein may be used in pneumatic applications, where the fluid includes a gas (e.g., air, nitrogen, oxygen, etc.). 
     As described herein, the valve body  102  includes an input fluid manifold attached to a plurality of micro-valves. The micro-valves and the input fluid manifold form a fluid plenum or reservoir configured to hold fluid received from an external fluid supply. In other embodiments, the valve body  102  may define a plurality of fluid plenums, each fluid plenum corresponding to at least a portion of the plurality of micro-valves. In such embodiments, each fluid plenum may be filled with a different colored ink (e.g., black, green, yellow, cyan, etc.) or a different fluid so as to provide multi-color capable jetting assembly or a multi fluid deposition assembly. In various embodiments, the micro-valves include an actuating beam configured to move (e.g., bend, curve, twist, etc.) in response to voltages being applied thereto to temporarily open fluid plenums at orifices in an orifice plate. As a result, droplets are emitted from the fluid outlets defined by the orifices onto a target to produce a desired marking pattern on the target. 
     As shown, a circuit board  104  is attached to a side surface of the carrier  108 . Circuit board  104  may include a plurality of electrical pathways and provide a point of connection between valve body  102  and an electrical controller (e.g., via a wiring harness). The electrical controller may supply control signals via the electrical pathways to control actuation of the actuating beams of multiple micro-valves included in the valve body  102 . The structure and function of such micro-valves are described in greater detail herein. In some embodiments, circuit board  104  itself includes a micro-controller that generates and provides control signals to actuate the micro-valves. 
     An identification tag  106  is attached to jetting assembly  100 . In some embodiments, identification tag  106  includes an internal memory configured to store various forms of information (e.g., manufacturing information, serial number, valve calibration information, settings, etc.) regarding jetting assembly  100 . For example, in one embodiment, identification tag  106  is a radio frequency identification (RFID) tag configured to transmit the stored information in a receivable manner in response to receiving a predetermined identifier from an external device. This way, information regarding jetting assembly  100  may be quickly and efficiently retrieved. 
     Referring now to  FIG.  2   , an exploded view of jetting assembly  100  is shown, according to an example embodiment. Carrier  108  includes a front-side surface  110 , a rear-side surface  112 , and a side surface  124 . In various embodiments, valve body  102  is attached to front-side surface  110  via an adhesive. The rear-side surface  112  has a cover  116  disposed thereon. Cover  116  includes apertures  120  providing supply ports for fluid (e.g., ink) for deposition onto a target via the valve body  102 . For example, in some embodiments, fluid (e.g., ink) is supplied to the valve body  102  via a first one of the apertures  120  (e.g., via an input supply line or hose), circulated through valve body  102 , and output from the valve body  102  via a second one of the apertures  120 . In other words, the fluid is recirculated through the fluid reservoir. A septum may be positioned in each of the apertures  120  and configured to allow insertion of a fluid delivery or fluid return pin or needle therethrough so as to allow communication of the fluid into the fluid reservoir while maintaining fluidic sealing of the jetting assembly  100 . In particular embodiments, the septum may include a single septum sheet which extends below each of the first one and the second one of the apertures. While not shown, in some embodiments, a heating element (e.g., a resistive wire) may be positioned proximate to the valve body  102  or the carrier  108  (e.g., around or coupled to side wall thereof). The heating element may be used to selectively heat the fluid (e.g., ink) contained within the fluid reservoir so as to maintain the fluid at a desired temperature. Furthermore, a temperature sensor (not shown), e.g., a thermal sense resistor, may also be provided in the carrier  108 , for example, to determine a temperature of the fluid flowing through the jetting assembly  100 . 
     The front-side surface  110  includes a cavity adapted to receive valve body  102  such that valve body  102  is mounted securely to the front-side surface  110  (e.g., via an adhesive). Circuit board  104  is attached to carrier  108  via the side surface  124 . As shown, the side surface  124  includes mounting pegs  126 . In various embodiments, circuit board  104  includes apertures arranged in a manner corresponding to the arrangement of the mounting pegs  126  and are adapted to receive the mounting pegs  126  to align the circuit board  104  to the carrier  108 . 
     As shown, circuit board  104  has a flex circuit  114  attached thereto. Flex circuit  114  extends at an angle from circuit board  104  and is attached to the carrier  108  proximate to the front-side surface  110 . The valve body  102  and circuit board  104  are arranged perpendicularly to one another, as the flex circuit  114  extends around a corner boundary of front-side surface  110 . Circuit board  104  also includes a controller interface  122  including electrical connection members (e.g., pins) configured to receive control signals from a marking system controller. 
     As described herein, in various embodiments, flex circuit  114  may be disposed between a fluid manifold and the carrier  108  (e.g., between an interposer disposed between the fluid manifold and the carrier  108 ) to facilitate formation of electrical connections between flex circuit  114  and electrodes of the plurality of micro-valves included in valve body  102 . In some embodiments, flex circuit  114  is attached to front-side surface  110  via a mounting member  148 . An opening in the flex circuit  114  is aligned with a septum in carrier  108  to provide a fluid inlet to a fluid plenum formed via the valve body  102 . 
     Referring now to  FIG.  3   , a schematic depiction of various components of jetting assembly  100  is shown, according to an example embodiment. For example,  FIG.  3    may depict a cross sectional view of jetting assembly  100  at the line I-I shown in  FIG.  1   . As shown, the valve body  102  extends from front-side surface  110  of the carrier  108  via an interposer  170 . The interposer  170  provides structural support to ensure maximal performance of various components in valve body  102 . While not shown, in some embodiments a compliant layer (e.g., a silicone or rubber layer) may also be disposed above or below the interposer  170  or any other location in the stack so as to provide stress relief. 
     The valve body  102  includes an input fluid manifold  162  and a plurality of micro-valves  164  attached to the input fluid manifold  162 . The micro-valves  164  and input fluid manifold  162  form a fluid reservoir  166  for fluid (e.g., a combination of ink and makeup fluid) received from a pressurized fluid supply (e.g., via apertures  120  in a cover  116  attached to the rear-side surface  112 ). In various embodiments, the fluid supply includes a fluid reservoir and a pump configured to provide pressurized fluid to jetting assembly  100  via a supply line coupled to carrier  108 . In various embodiments, the fluid supply supplies fluid pressurized between 7 and 15 PSI. For example, in one embodiment, the fluid has a pressure of approximately 10 PSI when one or more of the micro-valves are open. Carrier  108  may include an internal cavity configured to receive the pressurized fluid and deliver the fluid to the reservoir  166 . In various embodiments, a pressure differential may be maintained between the fluid reservoir  166  and the fluid supply so as to drive the fluid out of the valve body  102 . A pressure sensor may be provided in the valve body  102  and/or the carrier  108  to determine the pressure differential and/or pumping pressure of fluid pumped through the valve body  102 . 
     Input fluid manifold  162  may include a glass structure including a channel forming the fluid reservoir  166 . Generally, the micro-valves  164  include actuating beams held in spaced relation to orifices on an orifice plate at the front-side surface  110 . The actuating beams may include at least one layer of piezoelectric material configured to deflect in response to receiving control signals (e.g., drive pulses including drive waveforms such as electrical voltage waveforms provided via controller interface  122  on the circuit board  104 ). As described herein, application of such electrical signals causes the micro-valves  164  to open, which causes droplets to be released at the orifice plate. The droplets advance a throw distance  192  onto a substrate  190  to produce a desired pattern on the substrate  190 . In some embodiments, a weight of a single fluid droplet dispensed by a micro-valve  164  or any other micro-valve described herein may be in a range of 200 nanograms to 300 nanograms. In some embodiments, a volume of a single droplet dispensed may be in a range of 200 picoliter to 300 picoliter. The structure and function of various components of micro-valves  164  is described in greater detail herein. In other embodiments, the actuating beam may include a stainless steel actuating beam (e.g., having a length of approximately 1 mm). In still other embodiments, the actuating beam may include a bimorph beam having a two layers of a piezoelectric material disposed on either side of a base layer (e.g., a base silicon or stainless steel layer). An electrical signal (e.g., an electrical voltage) may be applied to either one of the piezoelectric layers so as to urge the actuating beam to bend towards the corresponding piezoelectric layer. The two piezoelectric layers may include the same piezoelectric material or different piezoelectric materials. In particular embodiments, a different electrical signal may be applied to each of the piezoelectric layer so as to bend or curve the actuating beam a predetermined distance towards or away from the orifice. 
     While embodiments described herein generally describe the actuating beam as including a piezoelectric material, in other embodiments, any other actuation mechanism may be used. For example, in some embodiments, the actuating beams may include a capacitive coupling for moving the actuating beams. In other embodiments, the actuating beams may include an electrostatic coupling. In still other embodiments, the actuating beams may include a magnetic coupling (e.g., an electromagnetic structure activated by an electromagnet) for moving the actuating beam. In yet other embodiments, the actuating beams may comprise a temperature sensitive bimetallic strip configured to move in response to temperature change. 
     Interposer  170  generally adds rigidity to various portions of the valve body  102 . For example, the interposer  170  may be constructed to be more rigid than components (e.g., the orifice plate, the actuating beam, etc.) of valve body  102  to counteract stressed induced by attaching such components to one another. For example, the interposer  170  may be attached to valve body  102  to counteract stresses induced by an adhesive used to attach the carrier  108  to the valve body  102 . Additionally, the interposer  170  may counteract stresses at interfaces between the input fluid manifold  162  and micro-valves  164 . 
     Referring now to  FIG.  4 A , a plan view of the jetting assembly  100  is shown, according to an example embodiment.  FIG.  4 A  shows a plan of valve body  102  at the line II shown in  FIG.  2   . As such,  FIG.  4 A  shows a cross-sectional view at an interface between input fluid manifold  162  and the orifice plate. Input fluid manifold  162  includes a first opening  172  and a second opening  174 . The first opening  172  exposes the plurality of micro-valves  164  to form the fluid reservoir  166  configured to hold fluid received from a fluid supply. 
     In the example shown, the plurality of micro-valves  164  include a plurality of actuating beams  176  aligned in a single row. Each of the plurality of actuating beams  176  has a sealing member  178  disposed at an end thereof. In some embodiments, the sealing members  178  are aligned with and contact valve seats disposed at orifices in the orifice plate to prevent fluid contained in the fluid reservoir  166  from escaping the fluid reservoir  166  in the absence of any electrical signals. The jetting assembly  100  is shown to include 52 actuating beams  176  forming 52 micro-valves  164 . In other embodiments, the jetting assembly  100  may include any other number of actuating beams. 
     In various embodiments, each of the plurality of actuating beams  176  extends from a member disposed underneath a boundary between the first and second openings  172  and  174 . Each of said members may include an electrical connection portion exposed via the second opening  174 . Electrical contact pads  180  are disposed at each of the electrical connection portions. Wire bonds electrically connect each of the electrical connection portions to the controller interface  122  via electrical contact pads  180 . As such, electrical signals may be received by each of the actuating beams  176  via the electrical contact pads  180 . In some embodiments tape-automated bonding (TAB) may be used to electrically connect each of the electrical connection portions to the controller interface. 
     The boundary between the first and second openings  172  and  174  isolates the electrical contact pads  180  from the fluid contained in a reservoir formed by the fluid opening  172 . Also beneficially, the electrical contact pads  180  are disposed beneath input fluid manifold  162 . This means that electrical connections between actuating beams  176  are disposed on the interior of carrier  108  and are protected from deterioration and external contamination. 
     To isolate electrical contact pads  180  from the fluid contained in the reservoir  166 , an adhesive structure  182  is disposed on input fluid manifold  162 . Adhesive structure  182  couples the input fluid manifold  162  to the orifice plate. As shown in  FIG.  4 A , adhesive structure  182  forms “racetracks” around each of the first and second openings  172  and  174 . The racetracks provide barriers for fluid that seeps between the input fluid manifold  162  and the orifice plate as well as prevent particles from entering the input fluid manifold. The racetrack adhesive structure  182  may be present on one or both of the input fluid manifold  162  side or the orifice plate side. For example, the racetracks may be constructed of several concentric loops of an adhesive material (e.g., a negative photo resist such as a bisphenol-A novalac glycidyl ether based photoresist sold under the tradename SU-8 or polymethylmethacrylate, polydimethylsiloxane, silicone rubber, etc.) around each of the first and second openings  172  and  174 . In other embodiments, the adhesive structure  182  may be formed from silicon and used to bond the input fluid manifold  162  to the orifice plate via fusion bonding, laser bonding, adhesives, stiction, etc. The adhesive structure  182  may be disposed on the input fluid manifold  162  and the valve body  102  coupled thereto, disposed on the valve body  102  and the input fluid manifold  162  coupled thereto, or disposed on each of the input fluid manifold  162  and the valve body  102  before coupling the two. 
     In some embodiments, the adhesive structure  182  may be vented. For example,  FIG.  4 B  shows a schematic illustration of an adhesive structure  182   b . The adhesive structure  182   b  may be formed from SU-8, silicon or any other suitable material and includes a plurality of loops  189   b  such that the adhesive structure has a race track shape. An inner most loop of the plurality of loops  189   b  of the adhesive structure  182   b  that surrounds the input fluid manifold  162  forms a closed loop. In contrast, the remaining of the plurality of loops  189   b  positioned radially outwards of the inner most loop include vents  183   b , for example, slots or openings defined therein. The vents  183   b  may facilitate bonding of input fluid manifold  162  to the orifice plate by allowing air that may get trapped in between the plurality of loops  189   b  of the adhesive structure  182   b  to escape via the vents  183   b . While  FIG.  4 B  shows the vents  183   b  being radially aligned with each other and located at corners of each loop, in other embodiments, one or more vents  183   b  of one loop may be radially offset from a vent defined in an adjacent loop, and formed at any suitable location in each of the plurality of loops  189   b.    
     As shown in  FIG.  4 B , corners of the each loop of the adhesive structure  182   b  may be rounded. Furthermore, corners of the input fluid manifold  162 , the interposer  170 , the flex circuit  114  or any other layers or components included in the jetting assembly  100  may be rounded, for example, to reduce stress concentration that can occur at sharp corners. 
     Referring now to  FIG.  5 A , a cross sectional view of a jetting assembly  200  including a micro-valve  230  is shown, according to an example embodiment. In some embodiments, jetting assembly  200  is an example embodiment of the jetting assembly  100  described with respect to  FIGS.  1 ,  2 ,  3 , and  4 A -B. As shown, jetting assembly  200  includes a carrier  202  attached to a valve body  298  via a structural layer  222 . In some embodiments, the carrier  202  may include the structural layer  222 . 
     Carrier  202  includes an upper portion  204  and a housing portion  206  extending from an edge of the upper portion  204 . Upper portion  204  includes a septum  208  through which pressurized fluid (e.g., ink) is provided. Housing portion  206  defines a cavity into which the valve body  298  is disposed. Valve body  298  includes an input fluid manifold  210  and the micro-valve  230 . As shown, input fluid manifold  210  and micro-valve  230  define a reservoir  300  configured to hold a volume of pressured fluid received from an external fluid supply via septum  208 . In various embodiments, the pressurized fluid held within the reservoir  300  is a combination of an ink and additional fluids in a liquid state. 
     Carrier  202  may be formed of plastic, ceramic, or any other suitable material. Carrier  202  facilitates operation of the jetting assembly  200  by providing structural support to valve body  298 . For example, in some embodiments, peripheral edges of valve body  298  are attached to housing portion  206  via layers of adhesive  302  disposed at the inner surface of housing portion  206 . Such adhesive facilitates maintenance of a desired relative positioning between micro-valve  230  and input fluid manifold  210 . 
     In various embodiments, input fluid manifold  210  is pre-formed prior to its attachment to the additional components of the jetting assembly  200 . Input fluid manifold  210  is formed by a body  310  (e.g., formed from glass, silicon, silica, etc.) having any suitable thickness (e.g., 500 microns). As shown, input fluid manifold  210  is pre-formed to include a first arm  330 , a second arm  332 , and a third arm  334 . As used herein, the term “arm,” when used to describe the input fluid manifold  210 , is used to describe a structure separating openings contained in the input fluid manifold  210 . As such, the arms  330 ,  332 , and  334  may have any suitable shape. For example, in some embodiments, the arms  330 ,  332 , and  334  are substantially rectangular-shaped, having substantially planar side surfaces. In other embodiments, the side surfaces may be angled such that the arms  330 ,  332 , and  334  are substantially trapezoidal-shaped. The arms  330 ,  332 , and  334  may be formed by creating openings in a glass structure using any suitable method (e.g., wet etching or dry etching such as deep reactive ion etching). 
     As shown, a first channel  212  separates the arms  330  and  332  from one another and a second channel  214  separates the arms  332  and  334  from one another. The first and second channels  212  and  214  are substantially linear and parallel to one another in the shown embodiment, but input fluid manifold  210  may be arranged as needed for the arrangement of micro-valves to be disposed thereon. First channel  212  is formed to have a width  304  bearing a predetermined relationship to a length  312  of a cantilevered portion  308  of an actuating beam  240  of the micro-valve  230 , for example, in a range of about 500-1,000 micron. For example, first channel  212  may be formed to have a width  304  greater than a desired length  312  of cantilevered portion  308  by a threshold amount. Second channel  214  provides an avenue for an electrical connection to be formed between the actuating beam  240  and a flex circuit  216  via wire bonds  220  extending in between. Beneficially, using such an arrangement internalizes electrical connections between actuating beam  240  and flex circuit  216 . In other words, electrical connections between such components are not external to carrier  202 , and are thus less vulnerable to degradation. In various embodiments, the first channel  212  and/or the second channel  214  may have inclined sidewalls. 
     As shown, second channel  214  is substantially filled with an encapsulant  218 . Encapsulant  218  may include an epoxy-type or any other suitable material. Encapsulant  218  envelopes electrical connections formed between wire bonds  220 , the flex circuit  216 , and actuating beam  240  and is configured to protect the wire bonds  220  from physical damage, moisture and corrosion. Thus, encapsulant  218  ensures the maintenance of an adequate electrical connection between flex circuit  216  and actuating beams  240  to facilitate providing electrical control signals to actuating beams  240  to cause movement thereof for opening and closing the micro-valve  230 . 
     The second arm  332  serves as a barrier preventing fluid contained in the reservoir  300  from reaching the electrical connections. As such, input fluid manifold  210  serves as both part of the reservoir  300  for pressured fluid received from an external fluid supply and an insulating barrier between the pressured fluids and any electrical connections contained within jetting assembly  200 . First and second channels  212  and  214  may be formed using any suitable process (e.g., via sandblasting, physical or chemical etching, drilling, etc.). In some embodiments, rather than being constructed of glass, input fluid manifold  210  is constructed of silicon, silica, ceramics or any other suitable material. In some embodiments, the input fluid manifold  210  may be bonded to the micro-valve  230  via glass frit, solder or any other suitable adhesive. 
     With continued reference to  FIG.  5 A , micro-valve  230  includes an orifice plate  250  attached to the actuating beam  240 . The orifice plate  250  may be formed from any suitable material, for example, glass, stainless steel, nickel, nickel with another layer of electroplated metal (e.g., stainless steel), polyimide (e.g., kapton) or a negative photoresist (e.g., SU-8, polymethylmethacrylate, etc.). Orifice plate  250  is substantially planar and includes an orifice  260  extending between surfaces thereof. In some embodiments, the orifice plate  250  may be substantially flat, for example, have a flatness with a coefficient of variance of less than 3 microns over a length and width of the orifice plate  250  of at least 15 mm, such that the orifice plate  250  is substantially free of bow or twist. Furthermore, the orifice plate  250  may have any suitable thickness. In some embodiments, the orifice plate  250  may have a thickness in a range of 30 microns to 60 microns (30, 40, 50, or 60 microns). In other embodiments, the orifice plate  250  may have a thickness in a range of 100 microns to 400 microns (e.g., 100, 150, 200, 250, 300, 350, or 400 microns). Thicker orifice plates  250  may facilitate realization of a flatter orifice plate. 
     In various embodiments, the orifice  260  is substantially cylindrical-shaped and has a central axis that is perpendicular or substantially perpendicular to surfaces of orifice plate  250 . A valve seat  270  is disposed on an internal surface  316  of orifice plate  250  proximate to orifice  260 . In various embodiments, valve seat  270  comprises a compliant material that surrounds or substantially surrounds orifice  260 . In some embodiments, valve seat  270  is constructed from an epoxy-based adhesive such as an SU-8 photoresist. In other embodiments, the valve seat  270  may be formed from a moldable polymer, for example, polydimethylsiloxane or silicone rubber. In still other embodiments, the valve seat  270  may be formed from a non-compliant material such as silicon. In some embodiments, a compliant layer, for example, a gold layer may be disposed on a surface of the valve seat  270  which is contacted by the actuating beam  240 . Valve seat  270  defines an interior opening  318  substantially aligned with orifice  260  to create an outlet for pressurized fluid contained in the reservoir  300 . In particular embodiments, the valve seat  270  might be excluded. 
     As shown, the actuating beam  240  extends a distance between a first end  336  and a second end  338 . Actuating beam  240  includes an end portion  328  extending from the first end  336  to a boundary of the second channel  214 . As shown, the end portion  328  is attached (e.g., via an adhesive layer) to the input fluid manifold  210  via a surface of the first arm  330 . The end portion  328  is disposed on spacing member  280 . As such, the end portion  328  is located between the spacing member  280  and the first arm  330 . In various embodiments, the end portion  328  includes each of the layers described with respect to  FIGS.  7 A-B  extending continuously therethrough. However, in alternative embodiments, any of the layers described with respect to  FIGS.  7 A-B  may not be included or include any number of discontinuities within the end portion  328 . 
     Actuating beam  240  further includes an electrical connection portion  294  extending from the end portion  328 . As shown, the electrical connection portion  294  extends in a region that corresponds to the second channel  214 . In other words, electrical connection portion  294  is located between the spacing member  280  and the channel  214 . As shown, the wire bond  220  connects to the actuating beam  240  via the electrical connection portion  294 . As described herein, the actuating beam  240  has a wire bond pad disposed thereon at the electrical connection portion  294  to form an electrical connection point. Via the electrical connection point, an electrical signal originating from an external controller travels to the actuating beam  240  via the flex circuit  216  and wire bond  220 . As described herein, the electrical signal may result in movement of a cantilevered portion  308  of the actuating beam  240  from a default position. Such a movement may open the fluid outlet defined at the orifice  260  such that fluid contained in the reservoir  300  is ejected from the valve body  298  and onto a desired surface. Various aspects of the electrical connection portion  294  are structured to facilitate operation of the micro-valve  230  in response to the electrical signal. 
     Actuating beam  240  further includes a base portion  306  extending from the electrical connection portion  294  to a boundary of the second arm  332 . As such, input fluid manifold  210  is attached to the actuating beam  240  via an adhesive disposed between the base portion  306  and the second arm  332 . In some embodiments, each of the layers described with respect to  FIGS.  7 A-B  extends continuously through the base portion  306 . In alternative embodiments, one or more of the layers described with respect to  FIGS.  7 A-B  may not be present within the base portion  306 . For example, in one embodiment, the passivation structure  406  and the second electrode portion  404  are not present within the base portion  306 . In such an embodiment, the adhesive attaching the actuating beam  240  to the second arm  332  directly contacts the layer of piezoelectric material within the base portion  306 . Alternatively, or additionally, any of the layers described with respect to  FIGS.  7 A-B  may include one or more discontinuities (e.g., gaps) within the base portion  306 . 
     The cantilevered portion  308  extends from the base portion  306  into the reservoir  300 . Since the base portion  306  is disposed on a spacing member  280 , the cantilevered portion  308  is spatially separated from orifice plate  250 . Thus, since the cantilevered portion  308  extends into the reservoir  300 , there is space on either side of cantilevered portion  308  such that it may bend towards and/or away from the orifice plate  250  as a result of application of the electrical signal thereto via electrical connection portion  294 . The spacing member  280  is configured to prevent squeeze film damping of the actuating beam. 
     Cantilevered portion  308  has a length  312  such that the cantilevered portion  308  extends from a boundary of the reservoir  300  by a predetermined distance. In various embodiments, the predetermined distance is specifically selected such that a portion  292  of cantilevered portion  308  overlaps the valve seat  270  and orifice  260 . A sealing member  290  extends from the portion  292  of the actuating beam  240  overlapping orifice  260 . In some embodiments, the sealing member  290  is constructed to have a shape that substantially corresponds to a shape of the orifice  260 . For example, in one embodiment, both orifice  260  and sealing member  290  are substantially cylindrical-shaped, with sealing member  290  having a larger outer diameter. Such a configuration facilitates sealing member  290  covering orifice  260  in its entirety to enable a seal to be formed between sealing member  290  and valve seat  270 . In other embodiments, the orifice  260  may have any other shape, e.g., star shape, square, rectangular, polygonal, elliptical or an asymmetric shape. In particular embodiments, the valve seat  270  may define a recess size and shaped to receive the sealing member  290 . In various embodiments, the orifice plate  250  and therefore, the orifice  260  may be formed from a non-wetting (e.g., hydrophobic) material such as silicon or Teflon. In other embodiments, a non-wetting (e.g., hydrophobic) coating may be disposed on an inner wall of the orifice  260 . Such coatings may include, for example, Teflon, nanoparticles, an oleophilic coating or any other suitable coating. 
     In various embodiments, spacing member  280  and sealing member  290  are constructed of the same materials (e.g., silicon, SU-8, silicon rubber, polymethylmethacrylate, etc.) and have equivalent or substantially equivalent thicknesses  320  and  322 . In such embodiments, when actuating beam  240  extends parallel to orifice plate  250 , lower surfaces of spacing member  280  and sealing member  290  are aligned with one another. When actuating beam  240  is placed into a closed position (as described herein), a surface of sealing member  290  contacts valve seat  270  to close the fluid outlet formed at orifice  260  (e.g., a sealing member surface of the sealing member  290  may be configured to extend approximately 2 microns beneath a lower surface of spacing member  280  if the valve seat  270  were not present). Valve seat  270  and sealing member  290  may be dimensioned such that sufficient surface area of the sealing member  290  contacts valve seat  270  when actuating beam  240  is placed in the closed position (e.g., when an electrical signal is removed from or applied to the actuating beam  240  via wire bonds  220 ) to prevent fluid from traveling from reservoir  300  to orifice  260 . For example, the sealing member  290  may have a larger diameter or otherwise cross-section than the valve seat  270 . In some embodiments, a compliant material (e.g., a gold layer) maybe disposed on a surface of the sealing member  290  that is configured to contact the valve seat  270 . 
     Various aspects of the structure of the cantilevered portion  308  are constructed to maximize the durability of the micro-valve  230 . In some embodiments, the second electrode portion  404  described with respect to  FIGS.  7 A-B  extends continuously through substantially the entirety of the cantilevered portion  308 . Such a structure provides maximal overlap between the second electrode and a layer of piezoelectric material within the cantilevered portion  308  such that electric signal may be applied to substantially the entirety of the cantilevered portion  308  to maximize the piezoelectric response. Because the cantilevered portion  308  extends into the reservoir  300 , the fluid contained within the reservoir  300  will contact the actuating beam  240 . The fluid contained within the reservoir  300  (e.g., any suitable combination of ink and makeup fluid) may corrode various materials out of which the actuating beam  240  is constructed. For example, in some embodiments, the electrodes contained in the actuating beam (e.g., the second electrode in the second electrode portion  404  described with respect to  FIGS.  7 A-B ) may be constructed of a material (e.g., platinum or gold) that corrodes in response to contact with the fluid. Thus, to ensure durability of the micro-valve, steps are taken to isolate the electrodes from the fluid. For example, the passivation structure  406  described with respect to  FIGS.  7 A-B  may be disposed on the second electrode such that the passivation structure  406  completely covers the second electrode. 
     To allow this to occur, the actuating beam  240  may be constructed such that a delimiting (e.g., outer circumferential) boundary of the second electrode is disposed inward of a delimiting boundary of the actuating beam  240 . For example, the layer of piezoelectric material contained within the actuating beam  240  may extend outward of the second electrode, and the passivation structure  406  may be disposed on the second electrode such that the passivation structure  406  completely covers the second electrode. In other words, an end  340  of the cantilevered portion  308  may not include the second electrode layer to facilitate complete passivation of the actuating beam  240 . 
     Various aspects of jetting assembly  200  are designed to ensure formation of an adequate seal between valve seat  270  and sealing member  290 . For example, structural layer  222  disposed on input fluid manifold  210  prevents bowing of orifice plate  250  resulting from stressed induced thereon via adhesives coupling components of micro-valve  230  to one another and the micro-valve  230  to housing portion  206 . In various embodiments, structural layer  222  is constructed to have a greater rigidity than orifice plate  250  to perform this function. Structural layer  222  may be constructed of silicon or any other suitable material. As shown, structural layer  222  includes protruding portions  224  extending from a main portion thereof. Protruding portions  224  are attached to an upper surface of input fluid manifold  210  (e.g., at boundaries of first and second channels  212  and  214 ). In certain embodiments, protruding portions  224  are omitted. A seal is formed at protruding portions  224  via, for example, an adhesive disposed between structural layer  222  and flex circuit  216 . Protruding portions  224  provide clearance above the input fluid manifold  210 . Such clearance facilitates disposal of encapsulant  218  that completely covers all points of contact between wire bond  220  and flex circuit  216 . In some embodiments, the carrier  202  may include the structural layer  222  such that the stiffness is provided by the carrier  202 . 
     In another aspect, actuating beam  240  is constructed such that a tight seal is formed at the interface between the valve seat  270  and the sealing member  290  when in the closed position. Actuating beam  240  may include at least one layer of piezoelectric material. The layer of piezoelectric material may include lead zirconate titanate (PZT) or any suitable material. The layer of piezoelectric material has electrodes electrically connected thereto. In various embodiments, wire bonds  220  are attached to said electrodes such that electrical signals from flex circuit  216  are provided to the layer of piezoelectric material via the electrodes. The electrical signals cause the actuating beam  240  to move (e.g., bend, turn, etc.) with respect to its default position. In other embodiments, the actuating beam  240  may include a stainless steel actuating beam (e.g., having a length of approximately 1 mm). In still other embodiments, the actuating beam  240  may include a bimorph beam having a two layers of a piezoelectric material disposed on either side of a base layer (e.g., a base silicon layer). An electrical signal (e.g., an electrical voltage) may be applied to either one of the piezoelectric layers so as to urge the actuating beam  240  to bend towards the corresponding piezoelectric layer. The two piezoelectric layers may include the same piezoelectric material or different piezoelectric materials. In particular embodiments, a different electrical signal may be applied to each of the piezoelectric layer so as to bend or curve the actuating beam a predetermined distance. 
     As shown, wire bonds  220  are attached to actuating beam  240  at an electrical connection portion  294  thereof. Electrical connection portion  294  includes a wire-bonding pad (e.g., constructed of gold or platinum) conductively connected to at least one electrode within actuating beam  240 . Beneficially, electrical connection portion  294  is separated from the cantilevered portion of actuating beam  240 . In other words, electrical connection portion  294  is separated from the fluid contained in jetting assembly  200  via seals formed at the points of connection between input fluid manifold  210  and actuating beam  240 . In some embodiments, the wire bonds  220  and/or the encapsulant  218  may be routed out through an opening provided in the orifice plate  250 . 
     In various embodiments, actuating beam  240  is constructed such that the closed position is its default position. In other words, various layers in the actuating beam  240  are constructed such that the actuating beam curves towards orifice  260  as a result of force supplied via pressured fluid contained in the fluid reservoir  212 . A tuning layer within actuating beam  240  may be constructed to be in a state of compressive stress to cause a curvature in actuating beam towards the orifice. As a result of such curvature, sealing member  290  contacts valve seat  270 , for example, in the absence of any electrical signals applied to the actuating beam  240  to close the fluid plenum. The degree of curvature may be specifically selected to form a tight seal at the interface between sealing member  290  and valve seat  270  with the actuating beam  240  in the default position. Beneficially, such a default seal prevents evaporation of the fluid contained in jetting assembly  200 , which prevents clogging and other defects. 
     The actuating beam  240 , as shown in  FIG.  5 A , is bent away from orifice plate  250 . Accomplishment of such a bend results from application of an electrical signal to actuating beam  240  via flex circuit  216 . For example, flex circuit  216  may be electrically connected to an external controller supplying electrical signals relayed to actuating beam  240 . 
     As illustrated by  FIG.  5 A , application of the electrical signal causes the actuating beam  240  to temporarily depart from its default position. For example, in various embodiments, the actuating beam  240  moves upward away from orifice  260  such that a portion of a sealing member surface of sealing member  290  is at least 10 microns from an upper surface of valve seat  270 . In one embodiment, a central portion of the sealing member surface is approximately 15 microns from the valve seat  270  at a peak of its oscillatory pattern. As a result, an opening is temporarily formed between valve seat  270  and sealing member  290 . The opening provides a pathway for a volume of fluid to enter orifice  260  to form a droplet at an exterior surface of the orifice plate  250 . The droplets are deposited onto a substrate to form a pattern determined via the control signals supplied to each of the actuating beams  240  of each of the micro-valves  230  of jetting assembly  200 . As will be appreciated, the frequency with which the actuating beam  240  departs from its default position to a position such as the one shown in  FIG.  5 A  may vary depending on the implementation. In various embodiments, the natural frequency of the actuating beams  240  may be in a range of a 1-30 kHz, and may be dependent on a length, a width, a thickness and/or a stiffness of the actuating beam  240 . For example, in one embodiment, the actuating beam  240  oscillates at a frequency of approximately 12 kHz. However, the actuating beam  240  may oscillate at a smaller (e.g., 10 kHz) or larger frequency (e.g., 20 kHz) in other implementations. 
     Referring now to  FIG.  5 B , a cross sectional view of a jetting assembly  200   b  including a micro-valve  230   b  is shown, according to an example embodiment. In some embodiments, jetting assembly  200   b  is an example embodiment of the jetting assembly  100  described with respect to  FIGS.  1 ,  2 ,  3 , and  4 A- 4 B . As shown, jetting assembly  200   b  includes a carrier  202   b  attached to a valve body  298   b  via an interposer  222   b.    
     Carrier  202   b  includes an upper portion  204   b  and a housing portion  206   b  extending from an edge of upper portion  204   b . A fluid channel  211   b  is provided in the upper portion  204   b . A septum  208   b  (e.g., a rubber or foam septum) is positioned at an inlet of the fluid channel  211   b  and a filter  213   b  is positioned at an outlet of the fluid channel  211   b . A cover  203   b  (e.g., a plastic or glass cover) is positioned on the carrier  202   b  such that the septum  208   b  is positioned between the carrier  202   b  and the cover  203   b , and secured therebetween. An opening  209   b  may be defined in the cover  203   b  and corresponds to the inlet of the fluid channel  211   b . A fluid connector  10   b  is coupled to the cover  203   b  or the inlet of the fluid channel  211   b . The fluid connector  10   b  includes an insertion needle  12   b  configured to pierce the septum  208   b  and be disposed therethrough in the fluid channel  211   b . The fluid connector  10   b  is configured to pump pressurized fluid (e.g., ink) into an input fluid manifold  210   b  of the jetting assembly  200   b  via the insertion needle  12   b . Furthermore, the filter  213   b  is configured to filter particles from the fluid before the fluid is communicated into the reservoir  300   b . In some embodiments, the insertion needle  12   b  may be formed from or coated with a non-wetting (e.g., a hydrophobic material such as Teflon). In other embodiment, the insertion needle  12   b  may include heating elements, or an electric current may be provided to the insertion needle  12   b  so as to heat the insertion needle  12   b  and thereby, the fluid flowing therethrough into the reservoir  300   b . In still other embodiments, metallic needles or any other heating element may be provided in the input fluid manifold  210   b  for heating the fluid contained therein. While shown as only including the fluid channel  211   b , in some embodiments, the carrier  202   b  may also define a second fluid channel for allowing the fluid to be drawn out of the carrier  202   b , i.e., cause the fluid to be circulated through the carrier  202   b.    
     The housing portion  206   b  defines a cavity or a boundary within which the valve body  298   b  is disposed. Valve body  298  includes the input fluid manifold  210   b  and the micro-valve  230   b . As shown, input fluid manifold  210   b  and micro-valve  230   b  define the fluid reservoir  300   b  configured to hold a volume of pressured fluid received from an external fluid supply via the septum  208   b . In various embodiments, the pressurized fluid held within the fluid reservoir  300   b  is a combination of an ink and additional fluids in a liquid state. 
     In various embodiments, input fluid manifold  210   b  is pre-formed prior to its attachment to the additional components of the jetting assembly  200   b . Fluid manifold  210   b  may be formed by a glass body  310   b  having any suitable thickness (e.g., 500 microns). As shown, input fluid manifold  210   b  is pre-formed to include a first channel  212   b  and a second channel  214   b . First channel  212   b  is formed to have a width  304   b  bearing a predetermined relationship to a length  312   b  of a cantilevered portion  308   b  of an actuating beam  240   b  of the micro-valve  230   b . Second channel  214   b  provides an avenue for an electrical connection to be formed between the actuating beam  240   b  and a flex circuit  216   b  via wire bonds  220   b  extending in between. 
     As shown, second channel  214   b  is substantially filled with an encapsulant  218   b . The encapsulant  218   b  ensures the maintenance of an adequate electrical connection between flex circuit  216   b  and actuating beams  240   b  to facilitate providing electrical control signals to actuating beams  240   b  to cause movement thereof to open and close micro-valve  230   b , and protects a wire-bond  220   b  from physical damage or moisture, as previously described herein. 
     The portion  314   b  of input fluid manifold  210   b  separating the first and second channels  212   b  and  214   b  serves as a barrier preventing fluid contained in the reservoir  300   b  from reaching the electrical connections. As such, input fluid manifold  210   b  serves as both part of the reservoir  300   b  for pressurized fluid received from an external fluid supply and an insulating barrier between the pressurized fluids and any electrical connections contained within jetting assembly  200   b.    
     The micro-valve  230   b  includes an orifice plate  250   b  attached to actuating beam  240   b . Orifice plate  250   b  is substantially planar and includes an orifice  260   b  extending between surfaces thereof. A valve seat  270   b  is disposed on an internal surface  316   b  of orifice plate  250   b  proximate to orifice  260   b . Valve seat  270   b  defines an interior opening  318   b  substantially aligned with orifice  260   b  to create an outlet for pressurized fluid contained in the reservoir  300   b . In particular embodiments, the valve seat  270   b  might be excluded. In some embodiments, the orifice plate  250   b  or any other orifice plate described herein may also be grounded. For example, an electrical ground connector  295   b  (e.g., a bonding pad such as a gold bond pad) may be provided on the orifice plate  250   b  and configured to allow the orifice plate  250   b  to be electrically ground (e.g., via electrical coupling to a system ground). 
     The actuating beam  240   b  includes a base portion  306   b  and a cantilevered portion  308   b . Base portion  306   b  extends underneath the portion  314   b  of input fluid manifold  210   b  separating the first and second channels  212   b  and  214   b . As shown, the base portion  306   b  includes an electrical connection portion  294   b  in a region that overlaps with the second channel  214   b . Electrical connection portion  294   b  includes an electrode through which an electrical connection is formed with flex circuit  216   b  via wire bonds  220   b . The cantilevered portion  308   b  extends into the reservoir  300   b  from the portion  314   b  of input fluid manifold  210   b . As shown, cantilevered portion  308   b  is disposed on a spacing member  280   b  and, as a result, is spatially separated from orifice plate  250   b.    
     Cantilevered portion  308   b  has a length  312   b  such that the cantilevered portion extends from a boundary of the reservoir  300   b  by a predetermined distance. In various embodiments, the predetermined distance is specifically selected such that a portion  292   b  of cantilevered portion  308   b  overlaps the valve seat  270   b  and orifice  260   b . A sealing member  290   b  extends from the portion  292   b  of the actuating beam  240   b  overlapping the orifice  260   b . In some embodiments, sealing member  290   b  is constructed to have a shape that substantially corresponds to a shape of orifice  260   b.    
     The flex circuit  216   b  is positioned on the glass body  310   b  and the portion  314   b  of the input fluid manifold  210   b , and coupled thereto via a first adhesive layer (e.g., SU-8, silicone rubber, glue, epoxy, etc.). An interposer  222   b  is positioned between the upper portion  204   b  of the carrier  202   b  and the input fluid manifold  210   b  so as to create a gap between the upper portion  204   b  and the input fluid manifold  210   b . This allows sufficient space for disposing the encapsulant  218   b  and increases a volume of the input fluid manifold  210   b . As shown in  FIG.  5 B , the interposer  222   b  is positioned on and coupled to a portion of the flex circuit  216   b  via a second adhesive layer  223   b  (e.g., SU-8, silicone, or any other adhesive). Furthermore, the interposer  222   b  is coupled to a side wall of the upper portion  204   b  of the carrier  202   b  proximate to the micro-valve  230   b  via a third adhesive layer  225   b  (e.g., SU-8, silicone, or any other adhesive). 
     The interposer  222   b  may be formed from a strong and rigid material (e.g., plastic, silicon, glass, ceramics, etc.) and disposed on input fluid manifold  210   b  so as to prevent bowing of the orifice plate  250   b  resulting from stressed induced thereon via adhesives coupling components of micro-valve  230   b  to one another and the micro-valve  230   b  to housing portion  206   b . In various embodiments, interposer  222   b  is constructed to have a greater rigidity than orifice plate  250   b  to perform this function. 
     In another aspect, actuating beam  240   b  is constructed such that a tight seal is formed at the interface between valve seat  270   b  and sealing member  290   b  when in the closed position. Actuating beam  240   b  may include at least one layer of piezoelectric material (e.g., lead zirconate titanate (PZT) or any suitable material). The layer of piezoelectric material has electrodes electrically connected thereto and wire bonds  220   b  are attached to said electrodes such that electrical signals from flex circuit  216   b  are provided to the layer of piezoelectric material via the electrodes. The electrical signals cause the actuating beam  240   b  to move (e.g., bend, turn, etc.) with respect to its default position. 
     As shown, wire bonds  220   b  are attached to actuating beam  240   b  at an electrical connection portion  294   b  thereof, substantially similar to the wire bonds  220  described with respect to the jetting assembly  200  of  FIG.  5 A . In various embodiments, actuating beam  240   b  is constructed such that the closed position is its default position, as described in detail with respect to the actuating beam  240  of  FIG.  5 A . 
     The actuating beam  240   b , as shown in  FIG.  5 B , is bent away from orifice plate  250 . Accomplishment of such a bend results from application of an electrical signal to actuating beam  240   b  via flex circuit  216   b . For example, flex circuit  216   b  may be electrically connected to a circuit board  215   b  (e.g., a printed circuit board) extending perpendicular to a longitudinal axis of the actuating beam  240   b  along a sidewall of the carrier  202   b . An identification tag  217   b  (e.g., the identification tag  106 ) may be positioned between the circuit board  215   b  and the sidewall of the carrier  202   b . An electrical connector  219   b  is electrically coupled to the circuit board  215   b  and configured to electrically connect the flex circuit  216   b  to an external controller supplying electrical signals relayed to actuating beam  240   b  via the circuit board  215   b.    
     As illustrated by  FIG.  5 B , application of the electrical signal causes the actuating beam  240   b  to temporarily depart from its default position. For example, in various embodiments, the actuating beam  240   b  moves upward away from orifice  260   b  such that a portion of a sealing member surface of sealing member  290   b  is at least 10 microns from an upper surface of valve seat  270   b , as described in detail with respect to the actuating beam  240  of  FIG.  5 A . 
     Referring now to  FIG.  6   , a more detailed view showing various components of jetting assembly  200  described with respect to  FIGS.  5 A-B  is shown, according to an exemplary embodiment. As shown, actuating beam  240  includes an actuating portion  242 , a tuning layer  244 , and a non-active layer  246 . Non-active layer  246  serves as a base for the tuning layer  244  and the actuating portion  242 . The structure of actuating portion  242  and the tuning layer  244  are described in greater detail with respect to  FIGS.  7 A-B . In some embodiments, non-active layer  246  is constructed from silicon or any other suitable material. In some embodiments, non-active layer  246 , the spacing member  280 , and sealing member  290  are all constructed from the same material (e.g., monolithically formed from a silicon wafer). In an example embodiment, non-active layer  246 , the spacing member  280 , and sealing member  290  are formed from a double silicon-on-insulator (SOI) wafer. 
     Spacing member  280  is shown to include an intermediate layer located between two peripheral layers. In an example embodiment, the intermediate layer and non-active layer  246  comprise two silicon layers of a double SOI wafer, with the peripheral layers disposed on either side of the intermediate layer including silicon oxide layers. In this example, the sealing member  290  and spacing member  280  are formed through etching the surface of the double SOI wafer opposite the actuating portion  242 . Oxide layers serve to control or stop the etching process once, for example, the entirety of the intermediate layer forming the spacing member  280  is removed in a region separating the spacing member  280  and sealing member  290 . Such a process provides precise control over both the width and thickness of the spacing and sealing members  280  and  290 . 
     As will be appreciated, the size of sealing member  290  may contribute to the resonance frequency of actuating beam  240 . Larger amounts of material disposed at or near an end of actuating beam  240  generally results in a lower resonance frequency of actuating beam. Additionally, such larger amounts of material may impact the actuating beam  240 &#39;s default curvature induced from pressurized fluid contacting actuating beam  240 . Accordingly, the desired size of sealing member  290  impacts various other design choices of actuating beam  240 . Such design choices are described in greater detail with respect to  FIGS.  7 A-B . In some embodiments, the sealing member  290  is sized based on the dimensions of orifice  260 . In some embodiments, the sealing member  290  is substantially cylindrical and has a diameter approximately 1.5 times that of the orifice  260 . For example, in one embodiment, sealing member  290  has a diameter of approximately 90 microns when the orifice  260  has a diameter of approximately 60 microns. Such a configuration facilitates alignment between sealing member  290  and orifice  260  such that sealing member  290  completely covers orifice  260  upon contacting valve seat  270 . In another embodiment, the sealing member  290  is sized such that it has a surface area that approximately doubles that of the orifice  260  (e.g., the spacing member  280  may have a diameter of approximately 150 microns, with the orifice  260  being approximately 75 microns in diameter). Such an embodiment provides greater tolerance for aligning sealing member  290  and orifice  260  to facilitate creating the seal between valve seat  270  and sealing member  290 . In other embodiments, the diameter of the sealing member  290  may be 2 times, 2.5 times, 3 times, 3.5 times or 4 times to the diameter of the orifice  260 . In various embodiments, a ratio of a length to diameter of the orifice  260  may be in range of 1:1 to 15:1. The ratio may influence shape, size and/or volume of a fluid droplet ejected through the orifice and may be varied based on a particular application. 
     Beneficially, the gap  324  between spacing member  280  and sealing member  290  creates a volume of separation  326  between actuating beam  240  and orifice plate  250 . The volume of separation  326  prevents squeeze film damping of oscillations of actuating beam  240 . In other words, insufficient separation between orifice plate  250  and actuating beam  240  would lead to drag resulting from fluid having to enter and/or exit the volume of separation  326  as the actuating beam  240  opens and closes the orifice  260 . Having the greater volume of separation produced via spacing member  280  reduces such drag and therefore facilitates actuating beam  240  oscillating at faster frequencies. 
     With continued reference to  FIG.  6   , orifice plate  250  includes a base layer  252  and intermediate layer  254 . For example, in one embodiment, base layer  252  comprises a silicon layer and intermediate layer  254  includes a silicon oxide layer. In the embodiment shown, a portion of the intermediate layer  254  proximate to orifice  260  is removed and a first portion of the valve seat  270  is disposed directly on base layer  252  and a second portion of the valve seat  270  is disposed on the intermediate layer  254 . It should be understood that, in alternative embodiments, intermediate layer  254  extends all the way to boundaries of orifice  260  and valve seat  270  is disposed on intermediate layer  254 . In still other embodiments, the removed portion of the intermediate layer  254  may have a cross-section equal to or greater than a cross-section of the valve seat  270  such that the valve seat  270  is disposed entirely on the base layer  252 . 
     Due to the criticality of the spatial relationship between spacing member  280  and valve seat  270 , attachment of spacing member  280  to orifice plate  250  may be performed in a manner allowing precise control over the resulting distance between actuating beam  240  and orifice plate  250 . As shown, an adhesive layer  256  is used to attach spacing member  280  to orifice plate  250 . In various embodiments, a precise amount of epoxy-based adhesive (e.g., SU-8, polymethylmethacrylate, silicone, etc.) is applied to intermediate layer  254  prior to placement of the combination of spacing member  280  and actuating beam  240  thereon. The adhesive is then cured to form an adhesive layer  256  having a precisely controlled thickness. For example, in some embodiments, a lower-most surface of spacing member  280  is substantially aligned with an upper surface of valve seat  270 . Any desired relationship between such surfaces may be obtained to create a relationship between sealing member  290  and valve seat  270  that creates an adequate seal when actuating beam  240  is in the default position. In various embodiments, the adhesive layer  256  and the valve seat  270  may be formed from the same material (e.g., SU-8) in a single photolithographic process. 
     In various embodiments, once the actuating beam  240  and orifice plate  250  are attached to one another via adhesive layer  256  (e.g., to form a micro-valve  230 ), an additional adhesive layer  248  is applied to the periphery of the actuating beam  240 . The additional adhesive layer  248  is used to attach input fluid manifold  210  to actuating beam  240 . 
     In the example shown with respect to  FIG.  6   , the micro-valve  230  includes a sealing structure  500  including various components through which a seal is formed to separate the orifice  260  from a volume proximate the actuating beam  240 . In the example shown, the sealing structure  500  includes the sealing member  290  and the valve seat  270 . As described herein, the actuating beam  240  is configured such that an orifice-facing surface of the sealing member  290  contacts an upper surface of the valve seat  270  to form a seal at the interface between the valve seat  270  and the sealing member  290 . The seal isolates the orifice  260  from the channel  212  such that minimal fluid escapes the jetting assembly  200  when no electrical signals are applied to the actuating beam  240 . In other embodiments, the valve seat  270  may be excluded such that the orifice facing surface of the sealing structure  500  contacts the orifice plate  250  so as to fluidly seal the orifice  260 . 
     Referring now to  FIG.  7 A , a more detailed view of actuating beam  240  is shown, according to an example embodiment and not to scale. As shown, actuating beam  240  includes the non-active layer  246 , the tuning layer  244 , a barrier layer  400 , a first electrode portion  402 , the actuating portion  242 , a second electrode portion  404 , and a passivation structure  406 . As will be appreciated, actuating beam  240  may include more or fewer layers in various alternative embodiments. 
     In some embodiments, tuning layer  244  is disposed directly on non-active layer  246 . Tuning layer  244  generally serves as an adhesion layer for facilitating deposition of the additional layers described herein. Additionally, as described herein, a thickness of tuning layer  244  may play a critical role in determining an overall curvature in actuating beam  240  when in its default position. Speaking generally, tuning layer  244  is configured to have a predetermined tuning stress such that in the closed position, the sealing member  290  of the actuating beam  240  contacts and exerts a force on the valve seat  270  so as to fluidly seal the orifice  260 . In some embodiments, in the absence of an electrical signal, the predetermined tuning stress is configured to cause the actuating beam  240  to curve towards the orifice  260  such that in the absence of the valve seat  270 , the sealing member surface of the sealing member  290  would be positioned a predetermined distance (e.g., 2 microns) beneath a lower surface of the spacing member  280 . For example, the tuning layer  244  may be placed into a state of compressive stress as a result of the deposition of the additional layers described herein. As such, the thicker tuning layer  244  is, the greater curvature of actuating beam  240  towards orifice  260  when in its default position. In one example embodiment, the tuning layer  244  is constructed of silicon dioxide. 
     Barrier layer  400  acts as a barrier against diffusion of materials contained in the first piezoelectric layer  414  to the tuning layer  244 . If left unchecked, such migration will lead to harmful mixing effects between constituent materials in the layers, adversely impacting performance. In various embodiments, barrier layer  400  is constructed of, for example, zirconium dioxide. As shown, first electrode portion  402  includes an adhesion layer  408  and a first electrode  410 . The adhesion layer  408  facilitates deposition of the first electrode  410  on barrier layer  400  and prevents diffusion of matter in the first electrode  410  to other layers. In various embodiments, adhesion layer  408  is constructed of titanium dioxide. First electrode  410  may be constructed of platinum, gold, rubidium, or any other suitable conductive material to provide a conductive pathway for electrical signals to be provided to actuating portion  242 . In some embodiments, first electrode portion  402  is only included in select portions of actuating beam  240 . For example, first electrode portion  402  may only be included proximate to and/or within the electrical connection portion  294 . 
     Actuating portion  242  may be formed from a single or multiple layers of any suitable piezoelectric material. In the example shown, active portion includes a growth template layer  412  and a piezoelectric layer  414 . Growth template layer  412  serves as a seed layer facilitating growth of the piezoelectric layer  414  having a desired texture (e.g., the {001} crystal structure and corresponding texture) to ensure maximal piezoelectric response. In some embodiments, growth template layer  412  is constructed of lead titanate. Piezoelectric layer  414  may be constructed of any suitable material such as lead zirconate titanate (PZT). 
     Piezoelectric layer  414  may be deposited using any method, such as, utilizing vacuum deposition or sol-gel deposition techniques. In some embodiments, piezoelectric layer  414  may have a thickness in a range of approximately 1-6 microns (e.g., 1, 2, 3, 4, 5, or 6 microns, inclusive) and is adapted to produce a deflection at an end of actuating beam  240  of approximately 10 microns when an electrical signal is applied thereto. A deflection of 10 microns (e.g., such that a surface of sealing member  290  departs from valve seat  270  by slightly less than that amount) may be sufficient to produce droplets at orifice  260  having a desired size. In some embodiments, piezoelectric layer  414  has a piezoelectric transverse coefficient (d31 value) magnitude of approximately 140 to 160 pm/V. This value may enable adequate deflection of actuating beam  240  to be generated via electrical signals supplied to first and second electrode portions  402  and  404 . 
     As shown, second electrode portion  404  is disposed on actuating portion  242 . In various embodiments, second electrode portion  404  is structured similarly to first electrode portion  402  described herein. Application of a voltage to the first electrode portion  402  and/or second electrode portion  404  thus induces a strain in piezoelectric layer  414 , causing the cantilevered portion  308  to bend away from the orifice plate  250 . Through application of periodic control signals to first and second electrode portions  402  and  404 , periodic cycling of actuating beam  240  generates droplets output from orifice  260  at a desired frequency. While  FIG.  7 A  shows the first and second electrode portions  402  and  404  overlapping each other, in other locations, the first and second electrode portions  402  and  404  may not overlap. This may limit or prevent electron leakage between the first and second electrode portions  402  and  404  which can damage the piezoelectric layer  414  or cause electrical shorts. 
     In various embodiments, the electrodes contained in first and second electrode portions  402  and  404  are deposited in a non-annealed state. As a result, the electrodes are deposited in a substantially compressive state, which impacts the overall curvature of actuating beam  240  when in a default position. The mode of deposition of piezoelectric layer  414  may impact the compressive state of the electrodes. For example, in some circumstances, where the piezoelectric layer  414  is deposited (e.g., via a vapor deposition technique) and later cured at a predetermined temperature (e.g., approximately 700 degrees C.), the curing may cause the electrode  410  to anneal and become removed from the compressive state. Such a removal impacts the overall balancing of stresses in actuating beam  240 , which changes its default curvature. Accordingly, it may be beneficial to use a low-temperature deposition process for piezoelectric layer  414  (e.g., a low-temperature sol-gel deposition process or plasma-enhanced chemical vapor deposition process) to prevent the reversal of stresses in the electrodes. In various embodiments, second electrode portion  404  may be annealed at a higher temperature than the first electrode portion  402 , for example, to create a predetermined tuning stress in the tuning layer  244 . 
     The materials shown in  FIG.  7 A  may extend substantially entirely through the length of actuating beam  240 . As such, there is an overlap between electrode portions  402  and  404  and the reservoir formed via micro-valve  230 . In various embodiments, the fluid contained in the reservoir is electrically conductive and/or corrosive to the materials forming the first and second electrode portions  402  and  404 . Thus, it is preferable to isolate electrode portions  402  and  404  from the reservoir to prevent the fluid contained in the reservoir from contacting electrode portions  402  and  404 . 
     In this regard, the passivation structure  406  is configured to perform such isolation. In the example shown, passivation structure  406  includes a dielectric layer  416 , an insulator layer  418 , and a barrier layer  420 . Barrier layer  420  may be constructed of silicon nitride, which acts as a diffusion barrier against water molecules and ions contained in the fluid to prevent corrosion of electrode portions  402  and  404 . In some embodiments, insulator layer  418  includes a silicon dioxide layer having a compressive stress that roughly counterbalances the tensile stress in barrier layer  420 . Dielectric layer  416  may be constructed of aluminum oxide to prevent oxidation of the additional layers contained in actuating beam  240 . In some embodiments, an additional metal layer is disposed on barrier layer  420 . For example, the metal layer may be constructed of Talinum oxide or any other suitable, chemically-resistant metal to further enhanced the protective properties of passivation structure  406 . In particular embodiments, the barrier layer  420  may be formed from Teflon or parylene. In other embodiments, at least a portion of the actuating beam  240 , i.e., the structure formed by the layers shown in  FIG.  7    may be covered or over coated by a Teflon or parylene layer. Such an overcoat may prevent micro-cracks from forming in the layers of the actuating beam  240 . In still other embodiments, the over coat may include a metallic layer, for example, a tantalum or palladium layer. 
     The addition of the passivation structure  406  may significantly impacts the default positioning of actuating beam  240 . This is so because passivation structure  406  is offset from a neutral axis  422  of compression of the actuating beam  240 . As shown, the neutral axis  422  is within the non-active layer  246 , which means that the electrode portion  404  and passivation structure  406  are the most distant therefrom in actuating beam  240 . Given this, the tensile or compressive stresses induced in such layers will greatly influence the default curvature of actuating beam  240 . As such, the thickness of tuning layer  244  is selected based on the structure of various constituent layers of passivation structure  406 . 
       FIG.  7 B  is front cross-sectional view of the actuating beam  240  showing an arrangement of each of the layers included in the actuating beam  240 , according to an example embodiment and not to scale. As shown, actuating beam  240  includes the non-active layer  246 , the tuning layer  244  and a barrier layer  400 , as described with respect to  FIG.  7 A . The first electrode portion  402  includes the adhesion layer  408  (e.g., titanium oxide) positioned on the barrier layer  400 , and a conductive layer or electrode  410  (e.g., platinum, gold, rubidium, etc.) positioned thereon. The first electrode portion  402  is configured to have a width which is less than a width of the barrier layer  400  such that ends of the electrode portion  402  in a direction perpendicular to a longitudinal axis of the actuating beam  240  are located inwards of the ends of the barrier layer  400  in the same direction. 
     The actuating portion  242  including the seed layer  412  and the piezoelectric layer  414  is conformally disposed on the first electrode portion  402  so as to extend beyond the lateral ends of the first electrode portion  402  and contact the barrier layer  400 . In this manner the piezoelectric layer completely surrounds or encapsulates at least the portion of the first electrode portion  402  which overlaps or is proximate to the second electrode portion  404 . The second electrode portion  404  includes an adhesion layer  403  (e.g., titanium) and a conductive layer  405  (e.g., platinum, gold, rubidium, etc.). In some embodiments, the second electrode portion  404  may include only the conductive layer  405  disposed directly on the piezoelectric layer  414  (i.e., the adhesion layer  403  is omitted). Since the actuating portion  242  overlaps and extends beyond the ends of the first electrode portion  402 , the actuating portion effectively electrically isolates the first electrode portion  402  from the second electrode portion  404 , so as to prevent electron leakage and current migration which may be detrimental to the performance of the actuating beam  240 . 
     The passivation structure  406  conformally coats exposed portions of each of the other layers  246 ,  244 ,  400 ,  402 ,  242  and  404 . However, a bottom surface of the non-active layer  246  may not be coated with the passivation structure  406 . The passivation structure  406  may include a dielectric layer  416 , an insulator layer  418 , a barrier layer  420 , and a top passivation layer  424 . Barrier layer  420  may be constructed of silicon nitride, which acts as a diffusion barrier against water molecules and ions contained in the fluid to prevent corrosion of electrode portions  402  and  404 . Silicon nitride, however, is generally in a state of tensile stress once deposited on the remaining layer. Insulator layer  418  is configured to counterbalance such tensile stress. For example, in some embodiments, insulator layer  418  includes a silicon dioxide layer having a compressive stress that roughly counterbalances the tensile stress in barrier layer  420 . In various embodiments, the barrier layer  420  may be positioned beneath the insulator layer  418 . Dielectric layer  416  may be constructed of aluminum oxide, titanium oxide, zirconium oxide or zinc oxide to prevent oxidation of the additional layers contained in actuating beam  240 . Thus, passivation structure  406  serves to prevent both corrosion and oxidation—two major sources of defects caused by the presence of fluids—in actuating beam  240 , and thus ensures long-term performance of micro-valve  230 . Furthermore, the top passivation layer  424  is disposed on the barrier layer  420  and may include a Teflon or parylene layer. Such an overcoat may prevent micro-cracks from forming in the layers of the actuating beam  240 , and may also prevent the underlying layer from a plasma discharge (e.g., which the buried layers may be exposed to in subsequent fabrication operations). In particular embodiments, the top passivation layer  424  may include a metallic layer, for example, a tantalum or palladium layer. In some embodiments, an additional metal layer is disposed on barrier layer  420 . For example, the metal layer may be constructed of Talinum oxide or any other suitable, chemically-resistant metal to further enhanced the protective properties of passivation structure  406 . 
       FIG.  8    shows a block diagram of a marking system  800 , according to an example embodiment. The marking system  800  is shown to include a controller  802 , a jetting assembly  808 , and a fluid supply  816 . Jetting assembly  808  may be constructed in a manner similar to the jetting assembly  200  described with respect to  FIGS.  5 A-B  and  6  herein. As such, the jetting assembly  808  includes a plurality of micro-valves  812 . Each of the micro-valves  812  includes an actuating beam (e.g., the actuating beam  240  or  240   b ) including a cantilevered portion that overlaps an orifice (e.g., the orifice  260  or  260   b ) in an orifice plate (e.g., the orifice plate  260  or  260   b ). The cantilevered portions are movable from a closed position in which sealing members attached to the cantilevered portions contact corresponding orifices or valve seats that surround corresponding orifices in response to control signals being received at electrical connection portions of the actuating beams. The control signals may include a drive pulse defining a drive waveform. 
     Such control signals may be supplied by the controller  802 . Controller  802  may be external to the marking device including the jetting assembly  808 . For example, controller  802  may be attached to a circuit board conductively connected to the micro-valves  812  (e.g., via a flex circuit  810 ) for providing separate control signals to each of the micro-valves  812 . Alternatively, in some embodiments, the controller  802  is included within the marking device and disposed within the same housing as jetting assembly  808 . 
     The controller  802  is shown to include a power supply  804  and a waveform generator  806 . Power supply  804  may include a battery or any other suitable power supply. The waveform generator  806  includes an electrical circuit configured to generate control signals for the micro-valves  812 . In some embodiments the waveform generator  806  is programmable. For example, in some embodiments, the waveform generator  806  includes a processor and a memory. The memory may store waveform parameters and instructions executable by the processor to generate waveforms having characteristics determined based on the parameters. The controller  802  may connect to an external computing device such that a user may adjust the parameters for specific ones of the micro-valves. By adjusting the parameters, various qualities of the drive waveform (e.g., voltage levels, pulse duration, etc.) may be adjusted based on the application. Waveform generator  806  may generate a plurality of individually adjustable waveforms for supply to each of the micro-valves via electrical connection lines  820 . Alternatively, the same control signal may be provided to each of the micro-valves  812 . 
     The controller  802  is conductively connected to the flex circuit  810 . For example, the connection lines  820  may connect to a circuit board attached to a carrier associated with the jetting assembly  808 . The circuit board may include a plurality of conductive pathways for each of the micro-valves  812 , which may be attached to the flex circuit  810 . As described herein, the flex circuit  810  may be electrically connected to electrical connection portions of each of the actuating beams of the micro-valves  812  via wire bonds. As such, via the flex circuit  810  and connection lines  820 , control signals may be provided to each of the micro-valves  812 . 
     Marking system  800  is shown to include a fluid supply  816 . Fluid supply  816  may be external to the marking device and fluidly coupled to the jetting assembly  808  via a fluid conduit  818 . Fluid supply  816  may include a pump for providing pressurized fluid to the jetting assembly  808 . The fluid may be pressurized at 3 PSI, 5 PSI, 7 PSI, 10 PSI, or any other suitable pressure. As described herein, jetting assembly  808  may include a valve body including a reservoir configured to receive the pressurized fluid. The reservoir may be in fluid communication with the orifices in the orifice plate when the actuating beams are removed from the closed position described herein. As such, when the control signals provided by the controller  802  reach the actuating beams of the micro-valves  812 , the actuating beams depart from the closed position to render the orifices in temporary fluid communication with the reservoir. With the actuating beams in an open position, droplets are ejected from the jetting assembly  808  through the orifices. Thus, by controlling the frequency with which the actuating beams depart from the closed position, the controller  802  determines the frequency at which drops are emitted from the jetting assembly  808 . 
     The actuating beams described herein oscillate in response to voltages above a threshold value being applied thereto. In certain embodiments, the threshold value is between 10 and 20 volts. In an example embodiment, the actuating beam  240  (or at least the cantilevered portion  308 ) oscillates response to a 20 volt control signal being applied thereto. During such an oscillation, the actuating beam  240  departs from the closed position, reaches a peak position (such as the position shown in  FIGS.  5 A-B ), returns to the closed position, and repeats a similar cycle any number of times. It should be noted that this oscillation occurs in response to application of a steady-state control signal (e.g., a direct current control signal) to the actuating beam  240 . 
       FIG.  9    shows an example oscillation pattern of an actuating beam  1000  in response to a control signal being applied thereto.  FIG.  9    shows a displacement of a tip  1002  of an actuating beam  1000  as a function of time (e.g., at points in time  902 ,  904 ,  906 ,  908 ,  910 ,  912 , and  914 ). The actuating beam  1000  and tip  1002  are depicted at the points in time  902 ,  904 ,  906 ,  908 ,  910 ,  912 , and  914  in  FIGS.  10 ,  11 ,  12 ,  13 ,  14 ,  15 , and  16   , respectively. As shown, at  902 , the tip  1002  is at or slightly below a default position. The point  902  may correspond to a point in time in which a control signal at a baseline or bias voltage is applied to the actuating beam  1000 . As shown, the bias voltage is approximately 6 volts. In alternative embodiments, the bias voltage is 10 volts or more. In still other embodiments, the bias voltage may include a negative bias voltage. The tip  1002  remains substantially at the default position until  906 , where an upswing portion of the drive waveform begins. During the upswing portion, the control signal voltage rises from the baseline or bias voltage to a predetermined drive pulse voltage. 
     Between  906  and  908 , the actuating beam  1000  bends at a substantially linear rate. Shortly after  906 , the drive signal may include a drive pulse which may reach a driving portion, where the control signal voltage reaches a predetermined drive voltage. In the example shown, the drive voltage is approximately 20 volts. In other embodiments, the drive voltage is 35 volts or higher. As shown, at  908 , the tip  1002  reaches a peak position, where the distance between the actuating beam  1000  (and any sealing members attached thereto) and the orifice reaches a maximal value. As depicted in  FIG.  13   , at  908 , a lower surface of the sealing member is displaced from the default position by approximately 16 microns. 
     Between  908  and  910 , the curve of the actuating beam  1000  reverses directions such that the tip  1002  approaches the default position and substantially reaches the default position at  910 . Between  910  and  912 , during which the drive waveform is still in the driving portion, the actuating beam oscillates again, but reaches a peak position slightly lower than that at  908 . As such, the oscillation between  910  and  912  has a slightly smaller period than the oscillation occurring between  906  and  910 . After  912 , the drive waveform returns to the bias voltage, and the actuating beam slightly oscillates around the baseline value, which is reached at  918 . 
     As shown in this example, during the driving portion of the drive waveform (e.g., approximately between  906  and  912  in  FIG.  9   ), the actuating beam  1000  oscillates multiple times. During these oscillations, the actuating beam  1000  departs from its default position, reaches a peak position, and returns to a point proximate to the default position. The initial oscillation after the drive pulse portion begins results in the largest peak value and the largest oscillation period. The values of this oscillation period may depend on various structural features of the actuating beam  1000  (e.g., the thicknesses of various layers, the final shape of any sealing member disposed thereon, etc.). 
     Because of these oscillations, the duration or length of the drive pulse is critical. If the drive pulse ends at a point in time proximate to when the actuating beam reaches a peak position (e.g., proximate to the point  908  described with respect to  FIG.  9   ), the actuating beam  1000  will quickly recoil back to the default position. As a result, the actuating beam  1000  strongly impacts against the orifice plate, which produces unwanted vibrations and disturbs operation of the incorporating micro-valve. These unwanted effects can be mitigated, by controlling a drive pulse ON time to have a period still at a time point where the actuating beam  1000  returns to its default position (e.g., proximate to the point  910  shown in  FIG.  9   ) with a relatively soft impact. This way, cutting of the drive pulse does not result in a strong impact of the actuating beam  1000  against the orifice plate, allowing the micro-valve to operate smoothly. The drive pulse ON time may be followed by a drive pulse OFF time, which may be configured to allow the actuating beam to stabilize in the closed position. The drive pulse OFF time may be less than the drive pulse ON time. In particular embodiments, the drive pulse OFF time may be at least 20% of the drive pulse duration (i.e., a total drive pulse time including the drive pulse ON time and the drive pulse OFF time). 
       FIG.  17    shows a chart of a tip displacement vs. time for an actuating beam with control signals having different waveforms applied thereto. As shown, three different waveforms are applied to the actuating beam. Each of the waveforms includes a 50 microsecond drive pulse ON time at 35 volts. The waveforms differ in that a first one of the waveforms does not include a bias pulse, a second one of the waveforms includes a 20 microsecond bias pulse at 10 volts, and a third one of the waveforms includes a 40 microsecond bias pulse at 10 volts. As shown, the tip follows a similar movement pattern despite the differences in waveform. The movement pattern includes a first oscillation  1702 , a second oscillation  1704 , and a third oscillation  1706 . As shown, the oscillations diminish in amplitude and period with time. Thus, to produce a single, well-defined oscillation of the actuating beam to produce well-defined fluid droplets, a period  1708  of the first oscillation  1702  is targeted as the duty cycle ON time. This way, the actuating beam only undergoes a single oscillation and sudden displacement of the oscillating beam resulting from cutting the drive pulse is prevented. 
       FIG.  18    shows an example drive waveform  1800  of a drive pulse that may be supplied to the micro-valves  812  via the controller  802 . As shown, the drive waveform  1800  includes an upswing portion  1802 , where a control signal voltage raises from zero to a predetermined voltage D. In some embodiments, during the upswing portion  1802 , the voltage increases linearly. For example, in one embodiment, the voltage increases at a rate of 20 volts per micro-second. The slope may be limited by the performance of the controller  802 . In some embodiments, the control signal may be communicated to a first electrode coupled to a first surface of a piezoelectric layer (e.g., the piezoelectric layer  414 ) of the actuating beam (e.g., actuating beam  240 ,  240   b ,  1000 ) located distal from the orifice plate (e.g., orifice plate  260 ,  260   b ) and a second electrode coupled to a second surface of the piezoelectric layer electrically coupled to common or system ground. In other embodiments, the first electrode is electrically coupled to the common or system ground and the control signal is provided to the second electrode. 
     Waveform  1800  further includes a driving portion  1804  where the control signal voltage holds steady at the predetermined voltage D for the drive pulse ON time. As described herein, the driving portion  1804  is of a duration that corresponds to a characteristic oscillation period of the actuating beam. Waveform  1800  also includes a downswing portion  1806  where the control signal voltage falls from the predetermined voltage D back to a baseline voltage. During the downswing portion  1806 , the voltage may drop at a linear slope that is substantially equivalent to the slope of the upswing portion  1802 . 
     As will be appreciated, the controller  802  may repeatedly apply any drive waveforms to the actuating beam to cause the actuating beam to oscillate at a drive frequency.  FIG.  19    shows an example where the controller applies multiple waveforms  1800 . There are gaps or drive pulse OFF times between the waveforms  1800  such that a drive pulse is applied to the waveform every predetermined period  1902 . As shown, the drive pulse ON time of the waveforms  1800  are less than half of the predetermined period  1902 . Such spacing between successive waveforms  1800  enables re-setting of the actuating beam to the default position with the orifice closed, and smoothens operation of the micro-valves  812  to facilitate droplet formation. 
       FIG.  20    shows another example drive waveform  2000  that may be applied to the micro-valves  812  via the controller  802 . Like the drive waveform  1800 , the drive waveform  2000  includes a drive pulse having a voltage upswing portion  2002 , a driving portion  2004 , and a voltage downswing portion  2006 . The drive waveform  2000  differs from the drive waveform  2000  in that the baseline voltage to which the control signal returns is a non-zero bias voltage B. The bias voltage B may be 6 volts, 10 volts, or any other suitable value. Offsetting the baseline voltage from zero increases the responsiveness of the actuating beam and facilitates operation at higher frequencies. In other embodiments, the bias voltage may include a negative bias voltage. 
       FIG.  21    shows another example drive waveform  2100  that may be applied to micro-valves  812  via the controller  802 . As shown, drive waveform  2100  includes a drive pulse having a biasing portion  2102  (also referred to herein as “bias pulse  2102 ”), a voltage upswing portion  2104 , a driving portion  2106 , and a voltage downswing portion  2108 . During the biasing portion  2102 , the control signal voltage is increases from zero volts to the bias voltage and is temporarily set at the bias voltage only prior to the voltage upswing portion  2104 , a driving portion  2106 , and a voltage downswing portion  2108 . In other words, after the driving portion  2106 , the control signal voltage drops to a substantially zero baseline value. It has been found that the waveform  2100  provides performance improvements over the waveform  2000  by increasing the volume of droplets emitted resulting from the actuating beam&#39;s oscillations.  FIG.  22    shows another example drive waveform  2200  that may be applied to micro-valves via the controller  802 . The waveform  2200  is substantially similar to the waveform  2100 , with the exception that it includes a stabilization plateau  2202  during the voltage downswing portion  2108 . The stabilization plateau  2202  is at a voltage level C that is lower than the bias voltage B. It has been found that the inclusion of such a plateau improves performance of the controller  802  and thus improves operation of the marking system  800 . 
     Referring now to  FIG.  23   , a flow diagram of a method  2300  of calibrating a micro-valve including an actuating beam is shown, according to an example embodiment. Method  2300  may be performed to determine a drive waveform (e.g., drive pulse ON time) for a micro-valve. Method  2300  may be repeated for any number of micro-valves to be included in a marking device. 
     In an operation  2302 , a bias voltage is applied to an actuating beam. For example, a controller (e.g., the controller  802 ) may apply a baseline voltage (having a zero or nonzero value) to an actuating beam. In an operation  2304 , a drive voltage is applied to the actuating beam to cause a cantilevered portion of the actuating beam to oscillate. For example, after application of the bias voltage, the controller may initiate application of a drive waveform that includes a voltage upswing portion where a control signal voltage increases to a predetermined voltage. The waveform may also include a driving portion where the control signal voltage remains constant at the predetermined voltage for the drive pulse ON time. The predetermined voltage may be selected to induce oscillations in the actuating beam. The predetermined voltage may be 20 volts or more. 
     In an operation  2306 , a return time of the cantilevered portion is determined. In some embodiments, the return time includes a characteristic initial oscillation period of the actuating beam in response to the drive voltage. The initial oscillation period may include a time between points at which the actuating beam is in a default position. Between such points, the actuating beam may reach a peak position at which the actuating beam is completely departed from an orifice included in the micro-valve. The return time may be measured a number of different ways. For example, sound or vibration measurements may be performed to determine the return time. A microphone or vibration sensor for performing such measurements is described in more detail below. 
     In an operation  2308 , a drive pulse length is determined based on the return time. In various embodiments the drive pulse ON time is selected to substantially correspond to, or exactly correspond to, the measured return time. In an operation  2310 , a drive waveform is set for the actuating beam. The drive waveform may be set to have any of the forms described with respect to  FIGS.  18 - 22   . The set drive form may be used to drive the actuating beam, in operation  2312 . 
       FIG.  24    shows a cross-sectional view of a jetting assembly  2400 , according to an example embodiment. Jetting assembly  2400  may have substantially the same structure as the jetting assembly  100  described with respect to  FIGS.  1 - 4   . As such, jetting assembly  2400  includes a fluid manifold  2402  that defines a first opening  2404  and a second opening  2406 . The second opening  2406  aligns with a plurality of electrical connection portions associated with a plurality of actuating beams to which the fluid manifold  2402  is attached. The first opening  2404  aligns with a plurality of micro-valves formed via the methods described herein. Specifically, a plurality of micro-valves  2408  are in fluid communication with the first opening  2404  to define a reservoir to receive pressurized fluid for dispensing of pressurized fluid thereby. However, in the jetting assembly  2400 , an isolated micro-valve  2410  is not in fluid communication with the first opening  2404 . For example, a wall may be formed in the first opening  2404  in the fluid manifold  2402  to isolate the micro-valve  2410  from the plurality of micro-valves  2408 . As such, a volume proximate to the actuating beam of the micro-valve  2410  may be void of any material, providing an empty chamber in which the actuating beam associated with the micro-valve  2410  to vibrate. 
     Since the actuating beam of the micro-valve  2410  has freedom to vibrate and does not dispense pressurized fluid, it can be used for alternative purposes. In some embodiments, the actuating beam is used as a microphone or vibration sensor. Since the actuating beam includes a layer of piezoelectric material, movements or bends of the actuating beam cause the layer of piezoelectric material to generate an electrical signal. The electrical signal is thus proportional to the acoustic response of the micro-valve  2410 . This acoustic response may be used as an indicator for various faults in the jetting assembly  2400  (e.g., connections between various components therein). Expanding further, a jetting assembly (e.g., the jetting assembly  2400 ) may include a plurality of micro-valves, each having an actuating beam. One of the actuating beams of the plurality of actuating beams may form the acoustic sensor. The acoustic sensor may be configured to move responsive to movement of any one of the other actuating beams and generate an electrical signal corresponding to the movement of the other actuating beam. In such embodiments, a controller (e.g., the controller  802 ) may be configured to measure the electrical signal from the acoustic sensor and determine if the other actuating beam is moving correctly based on the electrical signal. The controller may be further configured to provide a fault indication if the electrical signal departs from a baseline, the fault indication indicative of the other actuating beam not moving correctly 
     Referring now to  FIG.  25   , a flow diagram of a method  2500  of checking a jetting assembly for faults is shown, according to an example embodiment. Method  2500  may, for example, be performed by a controller (e.g., the controller  802 ) or an external computing device connected to the jetting assembly  2400  described with respect to  FIG.  24   . For example, a controller may receive electrical signals generated by the isolated micro-valve  2410  to identify potential faults in the jetting assembly  2400 . 
     In an operation  2502 , a response of an actuating beam to a predetermined sound stimuli is recorded. The sound stimuli may be selected to have a frequency within the bandwidth of the micro-valve  2410  such that the sound stimuli causes vibration of the micro-valve  2410 &#39;s actuating beam. Such vibrations may cause the layer of piezoelectric material contained in the actuating beam to generate an electrical signal. The electrical signal may be provided to the controller via wire bonds extending between the actuating beam and a flex circuit communicably coupled to the controller. The controller may store the response in memory for future analysis. In some embodiments, a plurality of sound stimuli are applied. For example, a plurality of sound stimuli at differing frequencies may be applied to measure the micro-valve  2410 &#39;s frequency response. 
     In an operation  2504 , the response is compared to a baseline response. For example, the controller may store a plurality of past responses of the micro-valve  2410  to the sound stimuli applied at operation  2502  for future comparisons. In an operation  2506 , jetting assembly faults are identified based on the comparison. For example, deviations of certain aspects of the response recorded at operation  2502  and the baseline response may be indicative of certain jetting assembly faults. A change in the micro-valve  2410 &#39;s frequency response, for example, may be indicative of a faulty connection between the orifice plate and the actuating beam, for example. Thus, via the micro-valve  2410  users may test the jetting assembly  2400  without performing invasive testing procedures thereon. 
     As previously described herein, application of a drive pulse to an actuating beam of a micro-valve may cause a tip of the actuating beam to move away from its default position (e.g., a closed position in which a sealing member disposed on a tip of the beam closes an orifice of the micro-valve) towards a peak or open position. In some instances however, the actuating beam may reach or over shoot a desired peak position and then recoil towards the orifice resulting in oscillations of the actuating beam, for example, as described with respect to  FIG.  9    wherein the actuating beam  1000  reverses direction such that the tip  1002  of the actuating beam  1000  approaches the default position and substantially reaches the default position at  910 . This may be undesirable as oscillation of the actuating beam, particularly movement of the tip back towards the default position during the drive pulse ON time may cause splattering of the ejected fluid due to kinetic energy of the tip of the actuating beam returning towards its default position, and/or ejection of inaccurate amount of the fluid. 
       FIG.  26    is a chart showing an example drive waveform  2600  of a drive pulse generated by a controller (e.g., the controller  802 ) to limit oscillations of the tip of the actuating beam so as to prevent splattering and enable ejection of an accurate amount of fluid from the micro-valve. The drive pulse is configured to move the actuating beam from the closed position to the peak position in which the corresponding orifice is open, and returns to the closed position in a characteristic period which may correspond to a total drive pulse ON time. 
     The drive waveform  2600  includes an opening portion  2620 , a deceleration portion  2630  and a hold portion  2640 . The opening portion  2620  comprises an opening voltage V o  configured to move the actuating beam towards the peak position at a velocity. The velocity may correspond to an amplitude of the opening voltage V o . The opening voltage may be sufficient to cause lift-off of a tip of the actuating beam from the orifice or a valve seat disposed around the orifice and sealed by the tip of the actuating beam towards the peak position thereby opening the micro-valve and allowing ejection of fluid through the orifice. 
     The drive waveform  2600  may also include a ramp portion  2610  for increasing a voltage applied to the actuating beam from a bias voltage V b  to the opening voltage V o  within a ramp time T r  (e.g., in a range of 1-3 μseconds). In some embodiments, the actuating beam may be unbiased before application of the drive pulse thereon, i.e., the bias voltage V b  is zero. In such embodiments, the actuating beam may be structured such that a default or resting position of the actuating beam may be the closed position in which a tip of the actuating beam seals the orifice (e.g., the actuating beam may be pre-stressed such that it inherently bends towards the orifice). In other embodiments, the controller (e.g., the controller  802 ) may be configured to apply a non-zero bias voltage V b  to the actuating beam when the drive pulse is not applied. The bias voltage V b  may reduce stress on the actuating beam without moving the actuating beam into the peak position away from the corresponding orifice and/or may urge the tip of the actuating beam towards the orifice, for example, to improve sealing of the orifice in the closed position, as previously described herein. The bias voltage V b  may include a positive or a negative bias. In such embodiments, the ramp portion  2610  increases the bias voltage V b  to the opening voltage V o  in the ramp time T r . 
     The opening voltage V o  may be applied to the actuating beam for an opening time T o  sufficient to curve the tip of the actuating beam proximate to the peak position but not reaching the peak position. The opening time may be in a range of 30-34 μseconds. To prevent the actuating beam from moving beyond the peak position relative to the corresponding office, the drive waveform  2600  includes the deceleration portion  2630  configured to retard the velocity of the actuating beam (e.g., a tip of the actuating beam) as it moves towards the peak position. Slowing the velocity of the actuating beam may allow the tip of the actuating beam to reach or substantially reach the peak position while preventing recoil of the tip of the actuating beam towards its default position and/or limit oscillation amplitude of the tip of the actuating beam about the peak position so as to reduce or otherwise eliminate splatter and allow ejection of accurate quantities of the fluid from the micro-valve. The deceleration portion  2630  is followed by the hold portion  2640  comprising a hold voltage V h  configured to hold the actuating beam proximate to the peak position for a hold time T h . In some embodiments, the hold voltage V h  may be substantially equal to the opening voltage V o . 
     The deceleration portion  2630  may include a first deceleration portion  2632  configured to decrease the opening voltage V o  to a deceleration voltage V d  lower than the opening voltage V o  but higher than the bias voltage V b  within a first deceleration time T d1  (e.g., in a range of 1-3 μseconds). The deceleration portion  2630  also includes a second deceleration portion  2634  configured to bias the actuating beam at the deceleration voltage V d  for a second deceleration time T d2  (e.g., in a range of 8-12 μseconds). The second deceleration portion  2634  is configured to slow the velocity of the tip of the actuating beam to prevent overshoot. A third deceleration portion  2636  included in the deceleration portion  2630  is configured to increase the deceleration voltage V d  to the hold voltage V h  within a third deceleration time T d3  (e.g., in a range of 8-12 μseconds). 
     While the second deceleration portion  2634  may serve to slow the velocity of the actuating beam to prevent overshoot from the peak position, the third deceleration portion  2636  increases the deceleration voltage V d  to the hold voltage V h  to maintain the tip of the actuation beam proximate to the peak position once it has reached or substantially reached the peak position. In this manner, the third deceleration portion  2640  may prevent over slowing of the actuating beam which may result in tip of the actuating beam being positioned substantially below the peak position or start returning towards the default position. Thus, a second deceleration time T d2  and the third deceleration time T d3  may be carefully controlled to slow the velocity of the actuating beam to prevent overshoot, while increasing the decelerating voltage V d  to the hold voltage V h  before the tip of the actuating beam starts returning towards its default position. 
     The drive waveform  2600  also includes a closing portion  2650  configured to return the actuating beam to the closed position within a closing time T c  (e.g., in a range of 1-3 μseconds), for example, by reducing the hold voltage to the bias voltage V b . The sum of each of the ramp time T r , a total deceleration time T d , a hold time T h  and the closing time T c  represents the characteristic period of the drive pulse and defines a volume or mass of the fluid ejected from the orifice of the micro-valve. The hold time T h  may be adjusted to vary a volume or mass of the fluid ejected from the orifice of the micro-valve. In various embodiments, the hold time T h  may be in a range of 5-100 μseconds (e.g., 5, 10, 15, 20, 25, 30, 35, 40, 50, 60, 70, 80, 90 or 100 μseconds) or even higher. 
     In some embodiments, the controller (e.g., the controller  802 ) may be configured to repeatedly apply a plurality of drive pulses including the drive waveform  2600  at a drive frequency. Each of the drive pulses may include a drive pulse ON time (e.g., the characteristic period during which the drive waveform  2600  is applied) in which the actuating beam moves into the peak position, and a drive pulse OFF time in which the actuating beam remains in the closed position. In other words, each drive pulse is separated by a drive pulse OFF time in which, for example, the actuating beam may be held at the biasing voltage V b  and maintained in the closed position. In particular embodiments, the drive pulse OFF time may be at least 10% of the drive pulse ON time. In various embodiments, the drive frequency of the drive pulse may be less than a natural oscillation frequency of the actuating beam (which may be in a range of 1-30 kHz). 
       FIG.  27    are plots showing motion of an actuating beam in response to a trapezoidal drive waveform that does not include the deceleration portion, and motion of the same actuating beam when driven by the drive waveform  2600 . With the trapezoidal waveform, the actuating beam experiences a first overshoot (overshoot 1) beyond the peak position, followed by a recoil of the actuating beam where the actuating beam returns close to the default position (i.e., proximate to the orifice) and then a second overshoot portion (overshoot 2) in which the actuating beam again overshoots the peak position. The overshooting and return proximate to the default position of the actuating beam in response to the trapezoidal waveform may result in splattering of the ejected fluid as previously described herein, which is undesirable. In contrast, the drive waveform  2600  causes the tip of the beam to approach the peak position without overshoot, thereby preventing splattering, and maintains the tip of the actuating beam proximate to the peak position for the hold time to allow an accurate amount of fluid to be ejected from the orifice. 
       FIG.  28    are plots showing motion of an actuating beam in response to a the drive waveform  2600  including hold portions  2640  having hold times T h  of 10, 25, 50 and 100 μseconds.  FIG.  29    shows a mass of the fluid ejected from the micro-valve including the actuating beam in response to the various hold times T h . As seen from  FIG.  29   , the mass of the ejected fluid may be adjusted approximately linearly by simply adjusting the hold time T h  of the hold portion  2640  of the drive waveform  2600 . 
       FIG.  30    is a schematic flow diagram of a method  3000  for driving an actuating beam (e.g., the actuating beam  240 ,  240   b  or any other actuating beam described herein) included in a micro-valve (e.g., the micro-valve  230 ,  230   b  or any other micro-valve described herein). In some embodiments, the method  3000  includes applying a bias voltage to the actuating beam, at  3002 . For example, the controller  802  may apply a positive or a negative bias voltage on the actuating beam so as to reduce stress on the actuating beam without moving the actuating beam into the peak position away from the orifice and/or urge the actuating beam towards the orifice so as to enhance a seal that the sealing member of the actuating beam forms with the orifice. 
     At  3004 , an opening voltage is applied to the actuating beam to move the actuating beam from a closed position, in which a corresponding orifice of the micro-valve is closed by the actuating beam, towards a peak position away from the corresponding orifice so as to open the corresponding orifice. For example, voltage applied to the actuating beam may be increased from the bias voltage V b  during the ramp portion  2610  of the drive waveform  2600  to the opening voltage V o  and maintained at the opening voltage V o  for the opening time T o . 
     At  3006 , the opening voltage is reduced to a deceleration voltage. At  3008 , the deceleration voltage is applied to the actuating beam for a deceleration time to prevent the actuating beam from moving beyond the peak position relative to the corresponding orifice. For example, the first deceleration portion  2632  may reduce the voltage applied on the actuating beam from the opening voltage V o  to the deceleration voltage V d . The second deceleration portion  2634  may maintain the deceleration voltage V d  on the actuating beam for reducing velocity of the beam and prevent overshoot beyond the peak position, as previously described herein. 
     At  3010 , the deceleration voltage is increased to a hold voltage. At  3012 , the hold voltage is applied to the actuating beam for a hold time to hold the beam proximate to the peak position for a predetermined time. For example, the deceleration portion  2636  may increase the voltage applied to the actuating beam from the deceleration voltage V d  to the hold voltage V h . The hold voltage V h  may be applied to the actuating beam for the hold time T h  during the hold portion  2640 , the hold time T h  being adjustable so as to allow ejection of a predetermined mass or volume of the fluid from the orifice of the micro-valve. In some embodiments, the hold voltage V h  may be equal to the opening voltage V o . At  3014 , the hold voltage is decreased until the actuating beam moves into the closed position. For example, the voltage applied on the actuating beam is decreased from the hold voltage V h  to the bias voltage V b  during the closing portion  2650  of the drive waveform  2600  to close the micro-valve. 
     In some embodiments, a marking system comprises a valve body comprises: an orifice plate including a plurality of orifices extending therethrough; a plurality of micro-valves, wherein each of the plurality of micro-valves comprises: an actuating beam movable from a closed position in which a corresponding one of the plurality of orifices is sealed by a portion of the actuating beam such that the micro-valve is closed, wherein the actuating beam is movable from the closed position into a peak position away from the corresponding one of the plurality of orifices in response to application of a control signal thereto; and a controller electrically connected to the actuating beams, the controller configured to generate a control signal for each of the actuating beams, wherein each control signal comprises a drive pulse having a predetermined voltage, wherein, in response to the drive pulse, the actuating beam oscillates such that the actuating beam moves from the closed position to the peak position in which the corresponding orifice is open and returns to the closed position in a characteristic period. 
     In some embodiments, the drive pulse of the marking system has a duration that substantially corresponds to the characteristic period such that the actuating beam is in the closed position after the drive pulse is complete. 
     In some embodiments, the controller is configured to repeatedly apply a plurality of the drive pulses to the actuating beam at a drive frequency 
     In some embodiments, each of the plurality of drive pulses comprises a drive pulse ON time in which the actuating beam moves into the peak position, and a drive pulse OFF time in which the actuating beam remains in the closed position. 
     In some embodiments, the drive pulse OFF time is at least 15% of the drive pulse duration. In some embodiments, a drive frequency of the drive pulse is less than a natural oscillation frequency of the actuating beam. In some embodiments, the natural frequency is in a range of 1 KHz and 30 KHz. In some embodiments, the controller is configured to apply a bias voltage to the actuating beam when the drive pulse is not applied to the actuating beam. 
     In some embodiments, the controller is configured to apply a bias voltage to the actuating beam such that the drive pulse is part of a drive waveform, and the drive waveform comprises a voltage upswing portion in which the control signal increases from the bias voltage to the predetermined voltage, a driving portion in which the predetermined voltage is applied for the drive pulse ON time, and a voltage downswing portion in which the control signal decreases from the predetermined voltage to the bias voltage. 
     In some embodiments, the bias voltage reduces stress on the actuating beam without moving the actuating beam into the peak position away from the orifice. In some embodiments, the bias voltage includes one of a positive bias voltage or a negative bias voltage. 
     In some embodiments, the controller is configured to apply a bias voltage to the actuating beam, such that the drive pulse is part of a drive waveform, and the drive waveform comprises a biasing portion in which the control signal increases from zero volts to the bias voltage, a voltage upswing portion in which the control signal increases from the bias voltage to the predetermined voltage, a driving portion in which the predetermined voltage is applied for the drive pulse ON time, and a voltage downswing portion in which the control signal decreases from the predetermined voltage to zero volts. 
     In some embodiments, the valve body further comprises a fluid manifold coupled to each of the plurality of micro-valves to define a reservoir configured to contain a pressurized fluid to be dispensed when the actuating beams depart from the closed positions. 
     In some embodiments, one of the actuating beams forms an acoustic sensor, the acoustic sensor configured to move in response to movement of any one of the other actuating beam and generate an electrical signal corresponding to the movement of the other actuating beam. 
     In some embodiments, the controller is further configured to measure the electrical signal from the acoustic sensor and determine if the other actuating beam is moving correctly based on the electrical signal. In some embodiments, the controller is configured to provide a fault indication if the electrical signal departs from a baseline, the fault indication indicative of the other actuating beam not moving correctly. 
     In some embodiments, a method of calibrating a marking system including at least one actuating beam, comprises: applying, by a controller electrically connected to an actuating beam of a micro-valve, a drive pulse to the actuating beam, the drive pulse having a predetermined voltage configured to induce an oscillation of the actuating beam; determining an oscillation period of a natural frequency of the actuating beam, the oscillation period including an interval between successive times in which the actuating beam is in a closed position where the actuating beam seals an orifice in an orifice plate on which the actuating beam is disposed such that the micro-valve is closed; determining a drive pulse ON time based on the oscillation period; and setting a drive waveform for the actuating beam, the drive waveform comprising a biasing portion in which the control signal increases from zero volts to a bias voltage, a voltage upswing portion in which a control signal voltage rises from a bias voltage to the predetermined voltage, a driving portion where the control signal voltage is at the predetermined voltage for the drive pulse ON time, and a voltage downswing portion in which the control signal voltage falls from the predetermined voltage to the bias voltage or zero. 
     In some embodiments, the drive pulse ON time is less than the natural oscillation period. In some embodiments, the predetermined voltage is 35 volts. 
     In some embodiments, the method further comprises repeating the actuating beam calibration method for each of a plurality of additional micro-valves included in the marking system. In some embodiments, the biasing portion has a biasing period less than the drive pulse ON time. 
     In some embodiments, the method further comprises driving the actuating beam using the drive waveform. 
     In some embodiments, a marking system comprises: a valve body comprising: an orifice plate including at least one orifice extending therethrough; at least one micro-valve comprising an actuating beam movable from a closed position, in which a corresponding orifice of the at least one orifice is sealed by a portion of the actuating beam such that the micro-valve is closed, towards a peak position away from the corresponding orifice in response to application of a control signal thereto; and a controller electrically connected to the actuating beam, the controller configured to generate a control signal for the actuating beam, wherein the control signal comprises a drive pulse configured to move the actuating beam from the closed position to the peak position in which the corresponding orifice is open and returns to the closed position in a characteristic period. The drive pulse includes a drive waveform comprising: an opening portion comprising an opening voltage configured to move the actuating beam towards the peak position at a velocity; a deceleration portion configured to retard the velocity of the actuating beam so as to prevent the actuating beam from moving beyond the peak position relative to the corresponding orifice; a hold portion comprising a hold voltage configured to hold the beam proximate to the peak position for a predetermined hold time; and a closing portion configured to return the actuating beam to the closed position. 
     In some embodiments, the controller is configured to apply a bias voltage to the actuating beam when the drive pulse is not applied to the actuating beam, and wherein the drive pulse further comprises a ramp portion configured to increase the bias voltage to the opening voltage within a ramp time. In some embodiments, the bias voltage reduces stress on the actuating beam without moving the actuating beam into the peak position away from the corresponding orifice. In some embodiments, the bias voltage includes one of a positive bias voltage or a negative bias voltage. In some embodiments, the hold voltage is substantially equal to the opening voltage. 
     In some embodiments, the deceleration portion comprises: a first deceleration portion configured to decrease the opening voltage to a deceleration voltage within a first deceleration time; a second deceleration portion configured to bias the actuating beam at the deceleration voltage for a second deceleration time; and a third deceleration portion configured to increase the deceleration voltage to the hold voltage within a third deceleration time. 
     In some embodiments, the first deceleration time is in a range of 1-3 μseconds, the second deceleration time is in a range of 8-12 μseconds and the third deceleration time is in a range of 8-12 μseconds. 
     In some embodiments, the controller is configured to repeatedly apply a plurality of the drive pulses to the actuating beam at a drive frequency. In some embodiments, each of the plurality of drive pulses comprises a drive pulse ON time corresponding to the characteristic period, and a drive pulse OFF time in which the actuating beam remains in the closed position. In some embodiments, the drive pulse OFF time is at least 10% of the drive pulse ON time. 
     In some embodiments, a drive frequency of the drive pulse is less than a natural oscillation frequency of the actuating beam. In some embodiments, the natural frequency is in a range of 1 KHz and 30 KHz. 
     In some embodiments, the valve body further comprises a fluid manifold coupled to each of the plurality of micro-valves to define a reservoir configured to contain a pressurized fluid to be dispensed when the actuating beams depart from the closed positions. 
     In some embodiments, one of the actuating beams forms an acoustic sensor, the acoustic sensor configured to move in response to movement of any one of the other actuating beams and generate an electrical signal corresponding to the movement of the other actuating beam. 
     In some embodiments, the controller is further configured to measure the electrical signal from the acoustic sensor and determine if the other actuating beam is moving correctly based on the electrical signal. In some embodiments, the controller is configured to provide a fault indication if the electrical signal departs from a baseline, the fault indication indicative of the other actuating beam not moving correctly. 
     In some embodiments, a method of driving an actuating beam included in a micro-valve, comprises: applying an opening voltage to the actuating beam for an opening time to move the actuating beam from a closed position, in which a corresponding orifice of the micro-valve is closed by the actuating beam, towards a peak position away from the corresponding orifice so as to open the corresponding orifice; reducing the opening voltage to a deceleration voltage; applying the deceleration voltage to the actuating beam for a deceleration time to prevent the actuating beam from moving beyond the peak position relative to the corresponding orifice; increasing the deceleration voltage to a hold voltage; applying the hold voltage to the actuating beam for a hold time to hold the beam proximate to the peak position for a predetermined time; and decreasing the hold voltage until the actuating beam moves into the closed position. 
     In some embodiments, method further comprises prior to applying the opening voltage, applying a bias voltage to the actuating beam to hold the beam in the closed position, wherein applying the opening voltage comprises increasing the bias voltage to the opening voltage. In some embodiments, the hold voltage is decreased to the bias voltage to move the actuating beam into the closed position. In some embodiments, the bias voltage reduces stress on the actuating beam without moving the actuating beam into the peak position away from the orifice. In some embodiments, the bias voltage includes one of a positive bias voltage or a negative bias voltage. In some embodiments, the hold voltage is substantially equal to the opening voltage. 
     As used herein, the terms “about” and “approximately” generally mean plus or minus 10% of the stated value. For example, about 0.5 would include 0.45 and 0.55, about 10 would include 9 to 11, about 1000 would include 900 to 1100. 
     As utilized herein, the terms “substantially’ and similar terms are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. It should be understood by those of skill in the art who review this disclosure that these terms are intended to allow a description of certain features described and claimed without restricting the scope of these features to the precise arrangements and/or numerical ranges provided. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and claimed are considered to be within the scope of the inventions as recited in the appended claims. 
     The terms “coupled,” “connected,” and the like, as used herein, mean the joining of two members directly or indirectly to one another. Such joining may be stationary (e.g., permanent) or moveable (e.g., removable or releasable). Such joining may be achieved with the two members or the two members and any additional intermediate members being integrally formed as a single unitary body with one another or with the two members or the two members and any additional intermediate members being attached to one another. 
     References herein to the positions of elements (e.g., “top,” “bottom,” “above,” “below,” etc.) are merely used to describe the orientation of various elements in the figures. It should be noted that the orientation of various elements may differ according to other exemplary embodiments, and that such variations are intended to be encompassed by the present disclosure. 
     The construction and arrangement of the elements as shown in the exemplary embodiments are illustrative only. Although only a few embodiments of the present disclosure have been described in detail, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter recited. For example, elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. 
     Additionally, the word “exemplary” is used to mean serving as an example, instance, or illustration. Any embodiment or design described herein as “exemplary” or as an “example” is not necessarily to be construed as preferred or advantageous over other embodiments or designs (and such term is not intended to connote that such embodiments are necessarily extraordinary or superlative examples). Rather, use of the word “exemplary” is intended to present concepts in a concrete manner. Accordingly, all such modifications are intended to be included within the scope of the present disclosure. Other substitutions, modifications, changes, and omissions may be made in the design, operating conditions, and arrangement of the preferred and other exemplary embodiments without departing from the scope of the appended claims. 
     Other substitutions, modifications, changes and omissions may also be made in the design, operating conditions and arrangement of the various exemplary embodiments without departing from the scope of the present invention. For example, any element disclosed in one embodiment may be incorporated or utilized with any other embodiment disclosed herein. Also, for example, the order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. Any means-plus-function clause is intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Other substitutions, modifications, changes and omissions may be made in the design, operating configuration, and arrangement of the preferred and other exemplary embodiments without departing from the scope of the appended claims.