WO2019013791A1

WO2019013791A1 - Fluid actuator control

Info

Publication number: WO2019013791A1
Application number: PCT/US2017/041830
Authority: WO
Inventors: James M. Gardner; Eric Martin; Daryl E. Anderson
Original assignee: Hewlett Packard Development Co LP
Current assignee: Hewlett Packard Development Co LP
Priority date: 2017-07-13
Filing date: 2017-07-13
Publication date: 2019-01-17
Anticipated expiration: 2020-01-13

Abstract

A fluid actuation system may include a first power path supplying power having a first voltage variability, a second power path having a second voltage variability less than the first range, a first fluid actuator having a first transistor gate to actuate the first fluid actuator, and a second fluid actuator having a second transistor gate to actuate a second fluid actuator. The first transistor gate is to be selectively supplied with power from the first power path. The second transistor gate is to be selectively supplied with power from the second power path.

Description

FLUID ACTUATOR CONTROL

BACKGROUND

[0001] Fluid actuators displace fluid. Fluid actuators may be utilized to form fluid pumps and may be utilized to form fluid ejectors. Fluid actuators may be used in a variety of different applications such as print media printing, three- dimensional printing, and the testing and analysis of fluid samples.

BRIEF DESCRIPTION OF THE DRAWINGS

[0002] Figure 1 is a schematic diagram illustrating portions of an example fluid actuation system.

[0003] Figure 2 is a flow diagram of an example method for controlling the actuation of fluid actuators.

[0004] Figure 3 is a schematic diagram illustrating portions of an example fluid actuation system.

[0005] Figure 4 is a schematic diagram illustrating portions of an example fluid actuation system.

[0006] Figure 6 is a schematic diagram illustrating portions of an example fluid actuation system.

[0007] Figure 7 is a schematic diagram illustrating portions of an example fluid ejection system.

[0008] Figure 8 is a schematic diagram illustrating portions of an example fluid ejection system. [0009] Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements. The figures are not necessarily to scale, and the size of some parts may be exaggerated to more clearly illustrate the example shown. Moreover, the drawings provide examples and/or implementations consistent with the description; however, the description is not limited to the examples and/or implementations provided in the drawings.

DETAILED DESCRIPTION OF EXAMPLES

[00010] Fluid actuators may be used to displace fluid on a fluidic die. Such fluid actuators may form a fluid pump or may form a fluid ejector. The fluid actuators may include a piezoelectric membrane based actuator, a thermal resistor based actuator, an electrostatic membrane actuator, a

mechanical/impact driven membrane actuator, a magneto-strictive drive actuator, or other such elements that may cause displacement of fluid responsive to electrical actuation. Fluidic dies described herein may comprise a plurality of fluid actuators, which may be referred to as an array of fluid actuators.

[00011] Some example fluidic dies comprise microfluidic channels.

Microfluidic channels may be formed by performing etching, microfabrication (e.g., photolithography), micromachining processes, or any combination thereof in a substrate of the fluidic die. Some example substrates may include silicon based substrates, glass based substrates, gallium arsenide based substrates, and/or other such suitable types of substrates for microfabricated devices and structures. Accordingly, microfluidic channels, chambers, orifices, and/or other such features may be defined by surfaces fabricated in the substrate of a fluidic die. Furthermore, as used herein a microfluidic channel may correspond to a channel of sufficiently small size (e.g., of nanometer sized scale, micrometer sized scale, millimeter sized scale, etc.) to facilitate conveyance of small volumes of fluid (e.g., picoliter scale, nanoliter scale, microliter scale, milliliter scale, etc.). Example fluidic dies described herein may comprise microfluidic channels in which fluidic actuators may be disposed. In such implementations, actuation of a fluid actuator disposed in a microfluidic channel may generate fluid displacement in the microfluidic channel. Accordingly, a fluid actuator disposed in a

microfluidic channel may be referred to as a fluid pump. Example fluidic dies disclosed herein may comprise a chamber adjacent a nozzle through which fluid is ejected. In such an implementation, actuation of the fluid actuator disposed in the chamber may generate fluid displacement such that the fluid is ejected through the nozzle.

[00012] The fluid actuators of fluidic dies are both driven and controlled with electrical power by power lines or power paths in the form of electrically conductive lines on the fluidic die. Such electrically conductive lines or paths may be in the form of wires or traces. Fluid actuators may be controlled with electrical switches or transistors. Such transistors selectively supply power to the fluid actuators to drive the fluid actuators in response to an applied gate voltage. The gate voltages are generated by a level shifter using power from a power path based upon received control signals.

[00013] The example fluidic dies disclosed herein may comprise fluid ejection dies that facilitate the selective ejection of fluid. In one implementation, the example fluidic dies may comprise printheads for a printing device. Such a printing device may print two-dimensional images on print media, wherein the fluid ejection die ejects fluid contained in a reservoir and were in the fluid may comprise ink, toner, varnish, gloss, a fixing agent or the like. Such a printing device may print three-dimensional objects, such as with a 3-D printer or additive manufacturing device. In some implementations, the fluid ejection dies may form part of a print cartridge. In yet other implementations, a plurality of such fluid ejection dies may form a page-wide device that is to span and print across a width of a print medium.

[00014] Disclosed herein are example fluid actuation systems that control the actuation of different fluid actuators through the generation of gate voltages using power supplied from different power paths having different degrees of voltage variability. Those fluid actuators that are less likely to detrimentally impact performance in response to voltage variations in the voltage used to generate the gate voltages that control actuation of the fluid actuators are actuated with gate voltages generated using power from a power path having a greater degree of voltage variability. Those fluid actuators that are more likely to detrimentally impact performance response to voltage variations in the voltage used to generate the gate voltages that control actuation of the fluid actuators are actuated with gate voltages generated using power from a power path having a lesser degree of voltage variability.

[00015] Disclosed herein are example fluid actuation systems that, for those first fluid actuators that are less likely to detrimentally impact performance in response to voltage variations in the voltage used to generate the gate voltage to actuate such first fluid actuators, uses power from the same power path to both drive such first actuators and to selectively control actuation of such first actuators. For those second fluid actuators that are more likely to detrimentally impact performance in response to voltage variations in the voltage used to generate the gate voltage to actuate each of such second fluid actuators, two different power paths may be used to drive and selectively control actuation of such second actuators. A first power path may supply power to drive such second actuators. A second, possibly more regulated, power path having a lower voltage variability may be used to supply power to generate the gate voltages that actuates each of such second actuators. [00016] In some implementations, the second power path having a lower voltage variability may deliver a regulated output of the first power path having the greater voltage variability. By using power from the first power path having the greater voltage variability to generate the fluid actuator actuation gate voltage for those fluid actuators that have a smaller impact on performance of the system while the same time using power from the second power path having a smaller voltage variability to generate the fluid actuator actuation gate voltage for those fluid actuators that have a greater impact on performance of the system, several advantages are achieved. In some implementations, the amount of parasitic loss experienced by those transistors that control actuation of those fluid actuators that have a smaller impact on performance of the system is reduced. Reducing the amount of parasitic loss experienced by such transistors reduces excess or waste heat. In some implementations, the voltage utilized to drive those fluid actuators that have a smaller impact on performance of the system may be higher. The size of the power supply for the second more regulated power path may be reduced. Moreover, the size of the regulation circuitry for the second, more regulated power path may also be reduced, reducing both cost and space consumption.

[00017] Disclosed herein are fluid actuation systems, fluidic dies and methods wherein those fluid actuators that form fluid pumps are actuated in response to actuation gate voltages generated using power supplied by the first power path having a greater degree of voltage variability, possibly the same power path that is used to drive the fluid actuators that form the fluid pumps. Fluid actuators that form fluid ejectors are actuated in response to actuation gate voltages generating using power supplied by the second power path having the lesser degree of voltage variability. In some implementations, the second power path delivers a regulated output of the first power path. [00018] Disclosed herein are fluid actuation systems, fluidic dies and methods wherein those fluid actuators that form fluid ejectors having a first drop weight are actuated in response to actuation gate voltages generated using power supplied by the first power path having a greater degree of voltage variability, possibly the same power path that is used to drive such fluid actuators. Fluid actuators that form fluid ejectors having a second drop weight, greater than the first drop weight, are actuated in response to actuation gate voltages generating using power supplied by the second power path having the lesser degree of voltage variability. In some implementations, the second power path delivers a regulated output of the first power path.

[00019] Disclosed herein are fluid actuation systems, fluidic dies and methods wherein those fluid actuators that displace a first fluid are actuated in response to actuation gate voltages generated using power supplied by the first power path having a greater degree of voltage variability, possibly the same power path that is used to drive the fluid actuators that form the fluid pumps. Fluid actuators that displace a second fluid, different than the first fluid are actuated in response to actuation gate voltages generated using power supplied by the second power path having the lesser degree of voltage variability. In some implementations, the second power path delivers a regulated output of the first power path.

[00020] In media printers that print images on to a print media, variations in the ejected drops of fluid may create visual defects in such images. However, some visual defects may be more difficult to detect with the human eye as compared to other visual defects. Visual defects resulting from variations in the ejected drops of a first fluid may be more difficult to detect with the human eye as compared to visual defects resulting from variations in the ejected drops of a second fluid. In such implementations, those fluid actuators that form fluid ejectors that eject the first fluid in such media printers are actuated in response to actuation gate voltages generated using power supplied by the first power path having the greater degree of voltage variability. In contrast, those fluid actuators that form fluid ejectors that eject the second fluid are actuated in response to actuation gate voltages generated using power supplied by the second power path having the lesser degree of voltage variability.

[00021] By way of example, variations in the ejected drops of a transparent liquid, such as a fixer, may produce visual defects in a printed image that are more difficult to detect with the human eye as compared to visual defects caused by corresponding variations in the ejected drops of a colored liquid. In such an implementation, those fluid actuators that form fluid ejectors for ejecting the transparent liquid are actuated in response to actuation gate voltages generated using power supplied by the first power path having the greater degree of voltage variability while those fluid actuators that form fluid ejectors for ejecting the colored liquid are actuated in response to actuation gate voltages generated using power supplied by second power path having the greater degree of voltage variability.

[00022] By way of another example, variations in the ejected drops of a certain colors of ink, such as yellow ink, may produce visual defects in a printed image that are more difficult to detect with the human eye as compared to visual defects caused by corresponding variations in the ejected drops of other colors of ink, such as cyan, magenta or black. In such an implementation, those fluid actuators that form fluid ejectors for ejecting yellow ink are actuated in response to actuation gate voltages generated using power supplied by the first power path having the greater degree of voltage variability while those fluid actuators that form fluid ejectors for ejecting the other non-yellow colors of ink are actuated in response to actuation gate voltages generated using power supplied by second power path having the greater degree of voltage variability. [00023] In additive manufacturing systems, the final three dimensional product being produced may be more sensitive to drop variations in a first type of liquid as compared to a second type of liquid. For example, additive

manufacturing systems may utilize a coalescent agent that controls the solidification or fusing of a building material and the detailing agent that inhibits solidification or fusing of the building material. In certain additive manufacturing systems, the final three dimensional product may be more sensitive to drop variations in the coalescent agent as compared to drop variations in the detailing agent. In such implementations, those fluid actuators that form fluid ejectors for the detailing agent are actuated in response to actuation gate voltages generated using power supplied by the first power path having the greater degree of voltage variability while those fluid actuators that form fluid ejectors for ejecting the coalescent agent are actuated in response to actuation gate voltages generated using power supplied by second power path having the greater degree of voltage variability.

[00024] Disclosed herein is an example fluid actuation system that may include a first power path supplying power having a first voltage variability, a second power path having a second voltage variability less than the first range, a first fluid actuator having a first transistor gate to actuate the first fluid actuator, and a second fluid actuator having a second transistor gate to actuate a second fluid actuator. The first transistor gate is to be selectively supplied with power from the first power path. The second transistor gate is to be selectively supplied with power from the second power path.

[00025] Disclosed herein is an example fluidic die that may include a power voltage path, a first set of level shifters connected to the power voltage path, a logic voltage path, a second set of level shifters connected to the logic voltage path, a first set of fluid actuators having first fluid actuator control transistor gates connected to the first set of level shifters and a second set of fluid actuators having second fluid actuator control transistor gates connected to the second set of level shifters.

[00026] Disclosed herein is an example method that may comprise generating a first gate voltage to actuate a first fluid actuator using power from a first power path having a first voltage variability and generating a second gate voltage to actuate a second fluid actuator using power from a second power path having a second voltage variability less than the first voltage variability.

[00027] Figure 1 is a schematic diagram illustrating portions of an example fluid displacement or actuation system 20. System 20 controls the actuation of different fluid actuators through the generation of gate voltages using power supplied from different power paths having different degrees of voltage variability. Those fluid actuators that are less likely to detrimentally impact performance in response to voltage variations in the voltage used to generate the gate voltages that control actuation of the fluid actuators are actuated with gate voltages generated using power from a power path having a greater degree of voltage variability. Those fluid actuators that are more likely to detrimentally impact performance response to voltage variations in the voltage used to generate the gate voltages that control actuation of the fluid actuators are actuated with gate voltages generated using power from a power path having a lesser degree of voltage variability.

[00028] System 20 comprises power paths 26A, 26B (collectively referred to as power paths 26), level shifters 28A, 28B (collectively referred to as level shifters 28) and fluid actuators 30A, 30B (collectively referred to as fluid actuators 30). Power paths 26A, 26B supply electrical power facilitate the generation of fluid actuator gate voltages for transistors to selectively actuate the respective fluid actuators 30A, 30B. In the example illustrated, power path 26A delivers power having a first voltage variability, meaning that the voltage of the power delivered on path 26A may fluctuate or vary to a first extent or degree (across a first range of voltages) during use of system 20. In one implementation, the voltage along path 26A may be dependent upon the number of fluid actuators that are being actuated at any one moment in time.

[00029] Power path 26B delivers power having a second voltage variability, less than the first voltage variability, meaning that the voltage of the power delivered on path 26B may fluctuate or vary to a second extent or degree less than the first extent or degree (across a smaller range of voltages) during use the system 20. In one implementation, power path 26B may be supplied with power from a regulator that more tightly controls the voltage delivered along path 26B. In one implementation, the regulator may itself receive power from path 26A and provide a regulated output of such power to path 26B. although each of paths 26 are illustrated as being connected to a single respective fluid actuator 30, it should be appreciated that each of such power paths 26 may be connected to an assigned set of fluid actuators or an assigned array of fluid actuators.

[00030] Level shifters 28A, 28B (sometimes referred to as translators) comprise devices or circuitry that generate a fluid actuator actuation gate voltage using power supplied by their respective power path 26A, 26B. In the example illustrated, each of level shifters 28 outputs the fluid actuator actuation gate voltage based upon actuation control signals received via signal transmitting lines 34. In such implementations, the actuation control signals may be at a small voltage, such as a voltage from 0 to 5 V, while the power supplied by the power paths 26 is at a much higher voltage. In one implementation, the voltage of the power supplied by power paths 26 is proximate to voltage of the power that drives fluid actuators 30.

[00031] In one implementation, the control signal voltage may be between zero and 5 V while the voltage supplied by power paths 26 may be in the range of 30-32 V for power path 26A and a regulated value of 29 V for power path 26B. In such an implementation, the fluid actuator actuation gate voltage supplied by level shifter 28A to fluid actuators 30A may be up to 32 V while the fluid actuator actuation gate voltage supplied by level shifter 28B to fluid actuators 30B may be 29 V.

[00032] Fluid actuators 30 comprise devices that displace fluid. The fluid actuators may include a piezoelectric membrane based actuator, a thermal resistor based actuator, an electrostatic membrane actuator, a

mechanical/impact driven membrane actuator, a magneto-strictive drive actuator, or other such elements that may cause displacement of fluid responsive to electrical actuation. Fluid actuators 30A, 30B are different from one another in that performance of system 20 is differently impacted by the performance of fluid actuators 30A, 30B. In one implementation, fluid actuators 30 may be structurally similar to one another, but disposed in different environments or in different surrounding structures so as to differently impact performance of system 20. For example, in one implementation, fluid actuator 30A may form a fluid pump of fluid actuators 30B forms a fluid ejector. In implementations where system 20 comprises an additive manufacturing printer or a print media printer, performance a system 20 may be more dependent upon the performance of fluid actuator 30B. [00033] In some implementations, fluid actuators 30 themselves may be structurally different so as to differently impact performance of system 20. For example, in some implementations, fluid actuators 30 may form fluid ejectors, but wherein fluid actuators 30A form fluid ejectors having a first drop weight and wherein fluid actuators 30B form fluid ejectors having a second greater drop weight. In implementations where system 20 comprises an additive

manufacturing printer or a print media printer, performance a system 20 may be more dependent upon the performance of fluid actuators 30B.

[00034] In some implementations, fluid actuators 30 may be structurally similar and may be disposed in structurally similar environments, but wherein the different fluid actuators 30 displace different types of fluid such that performance of the different fluid actuators differently impact performance of system 20. In media printers that print images on to a print media, variations in the ejected drops of fluid may create visual defects in such images. However, some visual defects may be more difficult to detect with the human eye as compared to other visual defects. Visual defects resulting from variations in the ejected drops of a first fluid may be more difficult to detect with the human eye as compared to visual defects resulting from variations in the ejected drops of a second fluid. In such implementations, those fluid actuators 30 A, 30B that form fluid ejectors that eject the first fluid in such media printers are actuated in response to actuation gate voltages generated using power supplied by the first power path 26A having the greater degree of voltage variability. In contrast, those fluid actuators 30B that form fluid ejectors that eject the second fluid are actuated in response to actuation gate voltages generated using power supplied by the second power path 26B having the lesser degree of voltage variability. For example, in some implementations, fluid actuator 30A may form a fluid ejector that ejects a transparent fluid while fluid actuator 30B forms a fluid actuator that ejects a colored fluid. In some implementations, fluid actuator 30A may form a fluid ejector that ejects yellow ink while fluid actuator 30B forms a fluid ejector that ejects a non-yellow ink, such as cyan, magenta or black ink. In each of such implementations, the performance of system 20 may be more dependent upon the performance of fluid actuator 30B as compared to the performance of fluid actuator 30A.

[00035] In additive manufacturing systems, the final three dimensional product being produced may be more sensitive to drop variations in a first type of liquid as compared to a second type of liquid. For example, additive

manufacturing systems may utilize a coalescent agent that controls the solidification or fusing of a building material and the detailing agent that inhibits solidification or fusing of the building material. In certain additive manufacturing systems, the final three dimensional product may be more sensitive to drop variations in the coalescent agent as compared to drop variations in the detailing agent. In one implementation, fluid actuator 30A may form a fluid ejector that ejects an additive manufacturing coalescent agent while fluid actuator 30B form the fluid ejector that ejects a detailing agent. In each of such implementations, the performance of system 20 may be more dependent upon the performance of fluid actuator 30B as compared to the performance of fluid actuator 30A.

[00036] Each of fluid actuators 30A and 30B has, is assigned or is associated with an actuation transistor 40A, 40B (collectively referred to as transistors 40) that selectively actuates the respective fluid actuators 30A, 30B, selectively turning on and off the respective fluid actuators 30A and 30B.

Transistors 40 each have a first portion 42 electrically connected to its respective fluid actuators 30A, 30B, a second portion 44 electrically connected to a power path that supplies electric power for driving the respective fluid actuators 30A, 30B and a gate 46. Gate 46 of each of transistors 40A, 40B are electrically connected to the respective level shifter 28A, 28B which selectively generates and applies the actuation gate voltage using power from the respective power path 26A, 26B and based upon the lower voltage control signals received from path or line 34.

[00037] In the example shown in Figure 1 , fluid actuator 30A is actuated by actuation gate voltages applied at gate 46 of transistor 40A and generated by level shifter 28A. Similarly, fluid actuator 30B is actuated by actuation gate voltage is applied at gate 46 of transistor 40B and generated by level shifter 28B. Level shifters 28A and 28B generate their respective actuation gate voltages using power from power paths 26A and 26B, respectively, which provide power with different degrees of voltage variability. For those fluid actuators having a greater impact on the performance of system 20, such as fluid actuator 30B, the power path having less voltage variability is utilized to generate the actuation gate voltage to turn on and off such fluid actuators. For those fluid actuators that have a less impact on the performance of system 20, such as fluid actuator 30A, the power path having greater voltage variability may be utilized to generate the actuation gate voltage to turn on and off such fluid actuators. This arrangement which customizes the power path used to generate the actuation gate voltages based upon the characteristics of the fluid actuator may reduce parasitic loss and waste heat, may facilitate the use of higher drive voltages for certain fluid actuators and may reduce both the size and cost of circuitry for controlling the actuation of the fluid actuators of system 20.

[00038] Although fluid actuators 30 are illustrated as being side-by-side on a single substrate of a fluidic die 21 , in other implementations, fluid actuators 30 may be arranged as part of an array or column on a single fluidic die. As indicated by broken lines, in other implementations, fluid actuators 30 may be supported on separate fluidic dies 21 'and 21 ". In some implementations, each of fluid actuators 30A, 30B may be part of a larger set of such fluid actuators, wherein each fluid actuator of the respective set is actuated using actuation gate voltages generated using power from the respective power path 26A, 26B based upon control signals.

[00039] Figure 2 is a flow diagram of an example method 100 for selectively actuating different fluid actuators of a fluid actuation system. Method controls the actuation of different fluid actuators through the generation of gate voltages using power supplied from different power paths having different degrees of voltage variability. Although method 100 is described as being carried out by system 20, it should be appreciated that method 100 may be carried out with any of the fluid actuation described hereafter or with similar fluid actuation systems.

[00040] As indicated by block 104, a first actuation gate voltage for actuating transistor 40A is generated using power from power path 26A having a first voltage variability. In the example illustrated, the actuation gate voltage, which turns on and off fluid actuator 30A, is generated by level shifter 28A using power from power path 26A based upon its control signals received via line 34.

[00041] As indicated by block 106, a second actuation gate voltage for actuating transistor 40B is generated using power from power path 26B having a second voltage variability less than the first voltage variability. In the example illustrated, the actuation gate voltage, which turns on and off fluid actuator 30B, is generated by level shifter 28B using power from power path 26B based upon its control signals received via line 34. As described above with respect to system 20, the first actuation gate voltage is used to turn on and off those fluid actuators that can tolerate variability in the actuation gate voltage without substantially detrimentally impacting the performance of the system, whereas the second actuation gate voltage is used to turn on and off those fluid actuators that may not tolerate variability in the actuation gate voltage without substantially detrimentally impacting the performance of the system.

[00042] Figure 3 schematically illustrates portions of another example fluid displacement or actuation system 220. System 220 is similar to system 20 described above in that system 220 controls the actuation of different fluid actuators through the generation of gate voltages using power supplied from different power paths having different degrees of voltage variability. Those fluid actuators that are less likely to detrimentally impact performance in response to voltage variations in the voltage used to generate the gate voltages that control actuation of the fluid actuators are actuated with gate voltages generated using power from a power path having a greater degree of voltage variability. Those fluid actuators that are more likely to detrimentally impact performance response to voltage variations in the voltage used to generate the gate voltages that control actuation of the fluid actuators are actuated with gate voltages generated using power from a power path having a lesser degree of voltage variability. System 220 is different from system 20 in that system 220 is specifically illustrated as comprising fluid actuators 230A, 230B (collectively referred to as fluid actuators 230), as additionally comprising control signal sources 248A, 248B (collectively referred to as control signal sources 248) and as having power path 26A supplying electrical power to each of fluid actuators 230 to drive electrical actuators 230. Those remaining components of system 220 which correspond once the system 20 are numbered similarly.

[00043] In the example illustrated, fluid actuators 230 each comprise a thermal resistor based actuator, wherein each actuator includes a resistor through which electrical current is passed and wherein the resistor generate a sufficient amount of heat to vaporize adjacent fluid, creating a bubble that forcefully expels or displaces the remaining adjacent under vaporized fluid. In other implementations, system 220 may comprise any of the other types of fluid actuators described above with respect to fluid actuators 30 of system 20.

[00044] Control signal sources 248A, 248B provide control signals to their respective level shifters 28A, 28B to control the generation of actuation gate voltages using power supplied by their respective power paths 26A and 26B. Control signal sources 248 output control signals having a voltage line within a range of 0 to V1.

[00045] As shown by Figure 3, in addition to supplying power for the generation of actuation gate voltages by level shifter 28A, power path 26A also supplies power for driving each of fluid actuators 230. As a result, the voltage of the power supplied by power path 26A may fluctuate or vary depending upon the number of fluid actuators 248 that are actually turned on or being actuated at any moment in time. In contrast, power path 26B does not drive fluid actuators 248 and is less susceptible to voltage variations. In one implementation, power path 26A supplies power having a voltage falling within the range of V4-V5 volts, wherein the actuation gate voltage applied to gate 46 of transistor 40A by level shifter 28A has a voltage falling within the range of 0 to V4 or V5 volts (whichever is higher). Transistor 40A experiences a maximum voltage drop based on the gate to source voltage (Vgs) of the transistor 40A which is a function of the transistor drive strength and current draw through actuator 230A. Power path 26B supplies power having a voltage falling with the range of V2 to V3 volts, wherein V3 is less than V4 and wherein the actuation gate voltage applied to gate 46 of transistor 40B falls within the range of 0 to V2 or V3 volts (whichever is higher). Transistor 40B experiences a maximum voltage drop larger than the voltage drop across transistor 40A. The smaller maximum voltage drop across transistor 40A reduces parasitic loss and waste heat. [00046] In one implementation, fluid actuator 230A forms a fluid pump a fluid actuator 230B forms a fluid ejector. In one such implementation, voltage V1 is 5 V, voltages V2 and V3 are 29 V, voltages V4 is 30 V and voltage V5 is 32 V. In such an implementation, transistor 40A experiences a voltage drop of 2 V while transistor 40B experiences a voltage drop in the range of 3 V to 5 V. The smaller voltage drop across transistor 40A reduces parasitic loss and waste heat.

[00047] Figure 4 schematically illustrates portions of an example fluidic displacement or actuation system 320. System 320 similar to system 220 described above except that system 320 is specifically illustrated as being employed as part of a fluid ejection die, wherein the fluid actuators form fluid pumps and fluid ejectors arranged in an array and wherein the power supplied by path 26B comprises a regulated output from path 26A, as regulated by a voltage regulator 318. Those components or elements of system 320 which correspond to components of system 220 are numbered similarly.

[00048] System 320 comprises a fluid ejection die comprising substrate 321 , wherein fluid actuators 230A, forming fluid pumps, and actuators 230B, forming fluid ejectors, are paired along a fluid supply 350, wherein each of the fluid pumps formed by a fluid actuator 230A circulates fluid to and/or from an associated fluid actuator 230B forming a fluid ejector.

[00049] As further shown by Figure 4, each fluid actuator 230B is part of a nozzle 352 having an ejection chamber 356 having an orifice 358 and in which the fluid actuator 230B is located. Each ejection chamber 356 is fluidically connected to fluid supply 350 by a fluid input 362 and a microfluidic channel 364. In the example illustrated, fluid input 362 and microfluidic channel 364 facilitate circulation of fluid into ejection chamber 356, through and across ejection chamber 356 and out of ejection chamber 356 back to fluid supply 350. In the example illustrated, such circulation is facilitated by a fluid pump formed by fluid actuator 230A within microfluidic channel 364.

[00050] In one implementation, fluid supply 350 comprises an elongated slot supplying fluid to each of the fluid actuators 230B of the array 362. In another implementation, fluid supply 350 may comprise an array of ink feed holes. In one implementation, fluid supply 350 further supplies fluid to fluid ejectors formed by fluid actuators 230B and fluid pumps formed by fluid actuators 230A located on an opposite side of fluid supply 350.

[00051] Similar to systems 20 and 220 described above, system 320 controls the actuation of different fluid actuators through the generation of gate voltages using power supplied from different power paths having different degrees of voltage variability. Those fluid actuators that are less likely to detrimentally impact performance in response to voltage variations in the voltage used to generate the gate voltages that control actuation of the fluid actuators are actuated with gate voltages generated using power from a power path having a greater degree of voltage variability. Those fluid actuators that are more likely to detrimentally impact performance response to voltage variations in the voltage used to generate the gate voltages that control actuation of the fluid actuators are actuated with gate voltages generated using power from a power path having a lesser degree of voltage variability.

[00052] Figure 5 schematically illustrates portions of an example fluidic actuation system 420. System 420 is similar to system 220 described above except that fluid actuators 230A, 230B are each specifically illustrated as forming fluid ejectors disposed within or proximate to ejection chambers 356 having nozzle orifices 358 (as described above), wherein fluid actuators 230A and 230B are fluidically connected to different fluid sources 460A and 460B, respectively. Those remaining components of system 420 which correspond to components of systems 20, 220 or 320 are numbered similarly. In some Implementations, power path 26B may deliver power from power path 26A after being regulated by a voltage regulator, such as regular 318 shown in Figure 4.

[00053] Fluid sources 460A, 460B (collectively referred to as fluid sources 460) supplied different types of fluid to the different fluid actuators 230A, 230B for being ejected by the different fluid actuators 230A, 230B, respectively. In one implementation, fluid sources 460 may supply the different fluids via different fluid supplies 350 (described above). For example, in some implementations, fluid source 460A may supply a transparent fluid for ejection by fluid actuator 230A while fluid source 460B supplies a colored fluid for ejection by fluid actuator 230B. In some implementations, fluid source 460A may supply a yellow ink for ejection by fluid actuator 230A while fluid source 460B supplies a non-yellow ink, such as cyan, magenta or black ink for ejection by fluid actuator 230B. In one implementation, fluid source 460A may supply an additive manufacturing coalescent agent for ejection by fluid actuator 230A while fluid source 460 B supplies a detailing agent for ejection by fluid actuator 230B, the coalescent agent controlling solidification or fusing of a building material and the detailing agent inhibiting solidification or fusing of the building material. In each of such implementations, the performance of system 20 may be more dependent upon the performance of fluid actuator 230B as compared to the performance of fluid actuator 230A.

[00054] Figure 6 schematically illustrates portions of an example fluid actuation system 520. System 520 is similar to system 420 described above except that system 520 controls the actuation of different fluid actuators through the generation of gate voltages using power supplied from different power paths having different degrees of voltage variability, wherein the power path that supplies power for generating actuation gate voltages for each actuator is based upon whether the fluid actuator is a fluid ejector or a fluid pump as well as the type of fluid being ejected by those fluid actuators that do form fluid pumps. Those components of system 520 which correspond to components of systems 20, 220, 320 and 420 are numbered similarly.

[00055] As shown by Figure 6, the example system 520 is illustrated as comprising a fluidic die 321 supporting a set or array of fluid actuators 230A1 , 230A2, 230B1 , 230B2 assigned to or associated with actuation transistors 40A1 , 40A2, 40B1 , 40B2 which receive actuation gate voltages generated by limit switches 28A1 , 28A2, 28B1 and 28B2, respectively. Each of fluid actuators 230A1 and 230A2 are similar to fluid actuators 230A described above, forming fluid pumps. Because fluid actuators 230A1 and 230A2 form fluid pumps which circulate fluid to the fluid ejectors and because variations in the performance of such fluid pumps due to variations in the actuation gate voltage have less of an impact upon the fluid ejection performance of system 520, fluid actuators 230A1 and 230A2 are actuated (turned on and off) in response to actuation gate voltages generated using power supplied by power path 26A.

[00056] Each of fluid actuators 230B1 and 230B2 are similar to fluid actuators 230B described above, forming fluid ejectors. In the example illustrated, fluid actuator 230B1 forms a fluid ejector that is supplied with fluid by fluid source 460B (described above) while fluid actuator 230B2 forms a fluid ejector that is supplied with fluid by fluid source 460A (described above). In the example illustrated, the performance of system 520 may be more dependent upon the reliability or consistency at which fluid from fluid source 460B is ejected as compared to the reliability or consistency at which fluid from fluid source 460A is ejected. As a result, fluid actuator 230B1 , which ejects fluid from fluid source 460B is actuated (turned on and off) in response to actuation gate voltages generated by level shifter 28B1 using power supplied by the power path having the lower degree of voltage variability, power path 26B. In contrast, fluid actuator 230B2, which ejects fluid from fluid source 460A is actuated (turned on and off) in response to actuation gate voltages generated by level shifter 28B2 using power supplied by the power path having a greater degree of voltage variability, the power path it may be regulated to a lesser extent or may not be connected to a voltage regulator, power path 26A. This arrangement which customizes the power path used to generate the actuation gate voltages based upon the both the function of the fluid actuator (pumping rejection) as well as the characteristics of the fluid being displaced by the particular fluid actuator may reduce parasitic loss and waste heat, may facilitate the use of higher drive voltages for certain fluid actuators and may reduce both the size and cost of circuitry for controlling the actuation of the fluid actuators of system 20.

[00057] Figure 7 is a schematic diagram illustrating portions of an example fluid ejection system 600. System 600 is to selectively eject fluid. System 600 comprises fluid ejection device 604 and print controller 606. Fluid ejection device 604 carries out the ejection of fluid in response to control signals from print controller 606. Fluid ejection device 604 comprises housing 608, fluid reservoir 610 and system/fluid ejection die 320.

[00058] Housing 608 comprises an enclosure, frame or other structure supporting fluid ejection die 320 (described above) and fluid reservoir 610. In some implementations, housing 608 may additionally enclose and support print controller 606.

[00059] Fluid reservoir 610 comprises an internal volume formed within the body of housing 608 for containing a fluid to be ejected by fluid actuators 230B on fluid ejection die 320. Fluid reservoir 610 is fluidically connected to fluid supply 350. [00060] Print controller 606 comprises a processing unit and associated non-transitory memory containing instructions for the operation of fluid ejection device 604. Print controller 606, following such instructions, outputs control signals that control the actuation of fluid actuators 230B to selectively eject fluid. In the example illustrated, print controller 606 is located remote from fluid ejection die 320 and remote from housing 608. In other implementations, print controller 606 may be located separate from fluidic die 320, but within housing 608. In other implementations, controller 606 may be located on fluid ejection die 320.

[00061] In one implementation, fluid ejection device 604 may comprise a print cartridge. Each of the fluid actuators 230 on fluid ejection die 320 are supplied with ink or other printing fluid from a self-contained fluid reservoir 610. In yet another implementation, fluid reservoir 610 may be replenished with ink or fluid from a fluid supply separate from the print cartridge formed by fluid ejection device 604. In such an implementation, fluid reservoir 610 may contain ink, toner, varnish, gloss, fixing agents and the like. In some implementations, fluidic die 320 may form a fluid ejection die in the form of a printhead.

[00062] Figure 8 schematically illustrates portions of an example fluid ejection system 700. Fluid ejection system 700 is similar to fluid ejection system 600 except that fluid ejection system 700 comprises fluid ejection device 704 which comprises a plurality of systems /fluid ejection dies 320 supported by housing 608. In one implementation, fluid ejection device 704 comprises a sufficient number of fluid ejection dies 320 so as to span and completely extend across and opposite to print media support 830 which positions print media, such as sheets of paper, opposite to fluid ejection device 704. In such an

implementation, fluid ejection device 704 may comprise what may be referred to as a page-wide print bar or page-wide fluid ejection device. In some

implementations, fluid ejection device 704 may comprise a plurality of fluid reservoirs 710 which supplied different types of fluid to the different fluidic dies. [00063] Although the present disclosure has fluid actuation system been described with reference to example implementations, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the claimed subject matter. For example, although different example implementations may have been described as including one or more features providing one or more benefits, it is contemplated that the described features may be interchanged with one another or alternatively be combined with one another in the described example implementations or in other alternative implementations. Because the technology of the present disclosure is relatively complex, not all changes in the technology are foreseeable. The present disclosure described with reference to the example implementations and set forth in the following claims is manifestly intended to be as broad as possible. For example, unless specifically otherwise noted, the claims reciting a single . Particular element also encompass a plurality of such particular elements. The terms "first", "second", "third" and so on in the claims merely distinguish different elements and, unless otherwise stated, are not to be specifically associated with a particular order or particular numbering of elements in the disclosure.

Claims

WHAT IS CLAIMED IS:

1. A fluid actuation system comprising:

a first power path supplying power having a first voltage variability;

a first level shifter connected to the first power path;

a second power path having a second voltage variability less than the first voltage variability;

a second level shifter connected to the second power path; a first fluid actuator having a first fluid actuator control transistor gate connected to the first level shifter; and a second fluid actuator having a second fluid actuator control transistor gate connected to the second level shifter.

2. The fluid actuation system of claim 1 , wherein the first power path supplies power to drive the first fluid actuator and second fluid actuator, wherein the second power path comprises a regulated output of the first power path.

3. The fluid actuation system of claim 1 , wherein the first fluid actuator and the second fluid actuator are on a single fluidic die.

4. The fluid actuation system of claim 1 comprising a first fluidic die comprising the first fluid actuator and a second fluidic die comprising the second fluid actuator.

5. The fluid actuation system of claim 1 , wherein the first fluid actuator is to displace a first fluid having first chemical properties and wherein the second fluid actuator is to displace a second fluid having second chemical properties different than the first chemical properties.

6. The fluid actuation system of claim 5, wherein the first fluid actuator is to displace a the first liquid for forming an image and wherein the second fluid actuator is to displace a second different liquid for forming the image, wherein visual defects caused by drop variances of the second liquid are more easily detected by the human eye as compared to visual defects caused by drop variances of the first liquid.

7. The fluid actuation system of claim 5, wherein the first fluid actuator is to displace a transparent fluid and wherein the second fluid actuator is to displace a colored fluid.

8. The fluid actuation system of claim 1 , wherein the first fluid actuator is to displace an additive manufacturing fusing agent and wherein the second fluid actuator is to displace an additive manufacturing detailing agent.

9. The fluid actuation system of claim 1 , wherein the first fluid actuator is to displace a first fluid having a first drop weight and wherein the second fluid actuator is to displace a second fluid having a second drop weight different than the first drop weight.

10. The fluid actuation system of claim 1 , wherein the first fluid actuator forms a fluid pump and wherein the second fluid actuator forms a fluid ejector.

11 . A fluidic die comprising: a power voltage path;

a first set of level shifters connected to the power voltage path;

a logic voltage path;

a second set of level shifters connected to the logic voltage path; a first set of fluid actuators having first fluid actuator control transistor gates connected to the first set of level shifters; and

a second set of fluid actuators having second fluid actuator control transistor gates connected to the second set of level shifters.

12. The fluid actuation die of claim 1 1 , wherein the first set of fluid actuators are to displace a first fluid and wherein the second set of fluid actuators are to displace a second fluid different than the first fluid.

13. The fluid actuation die of claim 1 1 , wherein the first set of fluid actuators form fluid pumps and wherein the second set of fluid actuators form fluid ejectors.

14. The fluid actuation die of claim 10, wherein the first set of fluid actuators comprise a first subset of fluid actuators that form fluid pumps and a second subset of fluid actuators that form first fluid ejectors that are to displace a first fluid and wherein the second set of fluid actuators form second fluid ejectors that are to displace a second fluid different than the first fluid.

15. A method comprising: generating a first gate voltage to actuate a first fluid actuator using power from a first power path having a first voltage variability; and

generating a second gate voltage to actuate a second fluid actuator using power from a second power path having a second voltage variability less than the first voltage variability.