TWI525001B - Inkjet printhead having common conductive track on nozzle plate - Google Patents

Description

Inkjet print head with common conductive traces on the nozzle plate

This invention relates to the field of printers, and more particularly to inkjet printheads. The present invention has been primarily developed to improve the print quality and print head performance of high resolution printheads.

Many different types of printheads have been invented, and most of them are still in use today. The conventional form prints various methods for the media to carry an associated tag medium. Printing forms generally used include offset printing, laser printing and copying devices, dot matrix impact printers, hot paper printers, film recorders, and hot wax printers. Dye sublimation printers and inkjet printers, which are available in both drop on demand and continuous flow types. Each type of printer has its advantages and disadvantages when considering factors such as cost, speed, quality, construction and ease of operation.

In recent years, each individual ink pixel has been inkjet printed from one or more ink nozzles because of its cheap and versatile nature, making it increasingly popular.

Many different techniques have been invented for ink jet printing. For a general discussion of this field, reference is made to J Moore, "Non-Impact Printing: Introduction and Historical Perspective", published in Output Hard Copy Devices, Editors R Dubeck and S Sherr pages 207-220 (1988).

There are many different types of inkjet printers themselves. The use of continuous ink streams in ink jet printing can be traced back to at least 1929, and a simple version of continuous flow electrostatic ink jet printing is disclosed in U.S. Patent No. 1,941,001, issued to Hansell.

A continuous ink jet printing process is also disclosed in U.S. Patent No. 3,596, 275 to Sweet, which is incorporated by the high frequency electrostatic field to effect droplet separation. This technology is still used by several manufacturers, including Elmjet Scitex (see U.S. Patent No. 3,373,437, owned by Sweet et al.).

Piezoelectric inkjet printers are also a common inkjet printing device. The operation of the piezoelectric mode is disclosed in U.S. Patent No. 3,946,398 (1970), which is incorporated herein by reference. U.S. Patent No. 3,683,212 (1970), which discloses the squeezing mode of a piezoelectric crystal. A piezoelectric operation in which a bending mode is disclosed in U.S. Patent No. 3,747,120 (1972), the disclosure of which is incorporated by reference to the disclosure of U.S. Patent No. 4,459,601, the disclosure of which is incorporated herein by reference. A piezoelectric transducer element of the shear mode type is disclosed in U.S. Patent No. 4,584,590.

Recently, thermal inkjet printing has become a very popular form of inkjet printing. Such ink jet printing techniques include those disclosed in U.S. Patent No. 4, 162, 728 to Endo et al. The ink jet printing technique disclosed in the aforementioned two patents relies on the action of an electrothermal actuator which causes a bubble to be generated in a restricted space, such as a nozzle, thereby causing ink to be connected from one to the other. The aperture of the restricted space is ejected onto an associated printing medium. Printing devices using such electrothermal actuators are manufactured by manufacturers such as Canon and Hewlett Packard.

As can be seen from the above description, there are many different types of printing techniques. Ideally, a printing technique should have several desirable characteristics. These features include low cost construction and operation, high speed operation, safe and continuous long term operation, and the like. Each technology has its own advantages and disadvantages in terms of cost, speed, quality, reliability, power usage, simplicity of construction and operation, durability and consumable.

The applicant of this case has revealed many page wide print head designs. The fixed pagewidth printhead (which extends over the entire width of a page) contains many unique design challenges when compared to conventional traverse inkjet printheads. For example, a pagewidth printhead is typically constructed of a plurality of separate printhead integrated circuits (ICs) that must be seamlessly combined to provide high print quality. The applicant of the present application has heretofore disclosed a print head having a shifting nozzle section that allows a row of nozzles across the entire page width to be seamlessly aligned between the butted print head integrated circuits. Printing (see U.S. Patent Nos. 7,390,071 and 7,290,852). Other pagewidth print method (e.g., HP Edgeline ^TM technology) using staggered print head module, which inevitably increases the size of the printing area and an additional requirement for the medium feeding means, and for The print area remains properly aligned. It is desirable to provide another nozzle design that allows the page width printhead to have a new construction.

Typically, a pagewidth printhead has a 'redundant' nozzle array that can be used for dead nozzle compensation or for the regulation of peak power requirements for the printhead (see US patent) No. 7,465,017 and 7,252,353, the contents of each of which are incorporated herein by reference. In contrast to traverse printheads, waste nozzle compensation is a particular problem in stationary pagewidth printheads because the media substrate passes through each nozzle of the printhead only once during printing. The extra nozzle array inevitably increases the cost and complexity of the page wide print head, so it is desirable to provide the appropriate nozzle count compensation while minimizing excess nozzle rows. mechanism.

It would be desirable to provide a pagewidth printhead capable of controlling, for example, more uniform droplet placement and/or droplet resolution.

It is further desirable to provide a print head having alternating integration of MEMS and CMOS layers. It is particularly desirable to minimize unwanted "ground bounce" phenomena and thereby improve the overall electrical efficiency of the printhead.

In a first aspect, an inkjet nozzle assembly is provided comprising: a nozzle chamber for containing ink, the nozzle chamber including a bottom wall and a top wall having a nozzle opening defined therein; and a plurality of movable paddles defining at least a portion of the top wall, the plurality of paddles being actuatable to cause ink droplets to be ejected from the nozzle opening, each pad comprising a thermal bend The actuator includes: an upper thermoelastic beam coupled to the drive circuit; and a lower passive beam fused to the thermoelastic beam such that when current is passed through the thermoelastic beam, the thermoelastic beam Relative to the passive beam expansion, causing the respective paddles to bend toward the bottom wall of the nozzle chamber, wherein each actuator can be independently controlled by a respective drive circuit such that a small droplet ejection direction from the nozzle opening can be Independent motion control for each paddle.

As used herein, "nozzle assembly" and "nozzle" are used interchangeably. Thus, "nozzle assembly" or "nozzle" refers to a device that ejects ink droplets as it is actuated. The "nozzle assembly" or "nozzle" typically includes a nozzle chamber having a nozzle opening and at least an actuator.

Optionally, the nozzle assembly is disposed on a substrate, and a passivation layer of the substrate defines a bottom wall of the nozzle chamber.

The upper wall is selected to be spaced apart from the bottom wall and the side wall extends between the top wall and the bottom wall to define the nozzle chamber.

The upper nozzle is selected to include a pair of opposed paddles disposed on either side of the nozzle opening.

The upper nozzle is selected to include two pairs of opposed paddles that are disposed relative to the nozzle opening.

The upper pad is selected and the paddles are movable relative to the nozzle opening.

Selecting the upper ground, each paddle defines a portion of the nozzle opening such that the nozzle opening and the paddles are movable relative to the bottom wall.

Selecting the upper layer, the thermoelastic beam comprises a vanadium aluminum alloy.

Preferably, the passive beam comprises at least one material selected from the group consisting of cerium oxide, cerium nitride and cerium oxynitride.

Selecting the upper ground, the passive beam comprises a first upper passive beam composed of yttria and a second lower passive beam composed of tantalum nitride.

The upper wall is selected to be coated with a polymeric material. The polymeric material can be constructed to provide a mechanical seal between each paddle and a stationary portion of the top wall to minimize ink leakage during actuation of the paddle. Alternatively, the polymeric material can have openings defined therein such that there is a fluidic seal between each paddle and a stationary portion of the top wall.

Optionally, the polymeric material comprises a polymerized decane.

Preferably, the polymerized oxane is selected from the group consisting of polysesquioxanes and polydimethyl methoxynes.

Selecting the upper ground, the actuators are independently controllable by controlling at least one of: a timing of driving signals to each of the actuators for providing one of the plurality of blades Coordinated actions; and the power of the drive signals sent to each of the actuators.

Selecting the ground, the power of the driving signals is controlled by at least one of: the voltage of the driving signals; and the pulse width of the driving signals.

In a further aspect related to the first aspect, an inkjet printhead integrated circuit is provided comprising: a substrate comprising a drive circuit; and a plurality of inkjet nozzles disposed on the substrate An ink jet nozzle assembly comprising: a nozzle chamber for containing ink, the nozzle chamber including a bottom wall defined by an upper surface of the substrate and a top wall having a nozzle opening defined therein And a plurality of movable paddles defining at least a portion of the top wall, the plurality of paddles being actuatable to cause ink droplets to be ejected from the nozzle opening, each paddle comprising a heat a bending actuator comprising: an upper thermoelastic beam coupled to the drive circuit; and a lower passive beam fused to the thermoelastic beam such that when current passes through the thermoelastic beam, the heat The resilient beams expand relative to the passive beam causing the respective paddles to flex toward the bottom wall of the nozzle chamber, wherein each actuator can be independently controlled by a respective drive circuit such that a small droplet ejection direction from the nozzle opening Independent motion control for each paddle system.

Selecting the upper layer, the upper surface of the substrate is defined by a passivation layer which is disposed on a driving circuit layer.

In a second aspect, a fixed pagewidth inkjet printhead is provided that is comprised of a plurality of printhead integrated circuits that are butted across the width of the page with ends that follow the end, the column The printhead includes one or more nozzle rows extending along a longitudinal axis of the printhead, each nozzle row comprising a plurality of nozzles, one or more of each nozzle being constructed to be along the longitudinal axis An ink droplet is emitted at a predetermined different point position.

Optionally, the one or more nozzles are each configured to emit an ink droplet along 2, 3, 4, 5, 6 or 7 different point locations of the longitudinal axis.

Preferably, each nozzle is configured to emit an ink droplet at a plurality of predetermined different point locations within a two-dimensional region having a predetermined dimension.

The upper zone is selected to be substantially circular or substantially elliptical, and wherein the center of the zone corresponds to the center of mass of the nozzle.

Preferably, the one or more nozzles are configured to emit an ink droplet at a primary point location and at least one point location on either side of the primary point location.

Selecting the upper ground, each nozzle assembly in a first group is configured to emit an ink droplet at a plurality of predetermined different point locations along the longitudinal axis, each nozzle in the first group being Within the two nozzle pitches of a waste nozzle in the printhead, one of the nozzle pitches is defined as the minimum longitudinal distance between a pair of nozzles in the same nozzle row.

Selecting the upper ground, each nozzle in a nozzle row is configured to emit an ink droplet at a plurality of predetermined different point locations along the longitudinal axis such that the printed dot density exceeds the printhead Nozzle density.

Selecting the upper ground, each butted print head integrated circuit pair defines a joint zone, and one of the nozzle pitches across the joint zone exceeds a nozzle pitch, and one nozzle pitch is defined as being in the same nozzle row The minimum longitudinal distance between a pair of nozzles.

Selecting a ground, wherein each nozzle in a second set is configured to emit an ink droplet at a plurality of predetermined different point locations along the longitudinal axis, the plurality of predetermined point locations including at least one The position of the point in the joint zone.

In a third aspect, a fixed pagewidth inkjet printhead is provided that includes one or more nozzle rows extending along a longitudinal axis of the printhead, wherein each nozzle is constructed to follow A plurality of predetermined different point locations of the longitudinal axis emit an ink droplet such that the printed dot density exceeds the nozzle density of the column head.

Optionally, the one or more nozzles are each configured to emit an ink droplet along 2, 3, 4, 5, 6 or 7 different point locations of the longitudinal axis.

Optionally, each nozzle can be configured to emit an ink droplet at a plurality of predetermined different point locations along the transverse axis of the printhead.

Selecting the upper level, the printed dot density is at least twice the nozzle density of the print head.

Selecting the upper ground, each nozzle is constructed to emit more than one time in one line-time, one of which is defined as the time it takes for a column of media to advance through a line of the print head.

In a fourth aspect, a fixed pagewidth inkjet printhead is provided that includes one or more nozzle rows extending along a longitudinal axis of the printhead, wherein each nozzle is constructed to follow A plurality of predetermined different point positions of the longitudinal axis emit ink droplets, each nozzle having a point position associated therewith, wherein the head is constructed to be in the same nozzle row as a waste nozzle A selected functioning nozzle is printed to compensate for the waste nozzle, the selected functional nozzle being configured to emit at least some of the ink droplets at a primary point associated with the waste nozzle and At least its ink droplets are emitted from its main point location.

Selecting the upper ground, the selected functional nozzle is at a distance of one, two, three or four nozzle pitches from the waste nozzle, wherein one nozzle pitch is defined as a pair in the same nozzle row The minimum longitudinal distance between the nozzles.

Selecting the upper head, the print head is constructed to compensate the waste nozzle by the following steps: identifying the waste nozzle; selecting a functional nozzle to compensate the waste nozzle; and constructing the selected functional nozzle for The primary point location associated with the waste nozzle emits at least some of the ink droplets.

Selecting the upper ground, the selected functional nozzle is configured to emit the first ink droplet at a primary point location associated with the waste nozzle and to emit a second ink at its primary point location during a line time period A small droplet, one of which is defined as the time it takes for a column of media to advance through a line of the printhead.

Optionally, each nozzle can be further configured to emit an ink droplet at a plurality of predetermined different point locations along the transverse axis of the printhead.

Selecting the upper ground, the selected functional nozzle is configured to emit the first ink droplet at a primary point location associated with the waste nozzle during a period greater than one line time and less than five line times A second ink droplet is emitted at its primary point location.

Selecting the upper layer, each droplet that is perpendicular to the inkjet surface of the printhead will cause the droplet to land at the respective primary point location.

Selecting the upper head, the print head is constructed to compensate for a plurality of waste nozzles by printing from a corresponding plurality of selected functional nozzles.

Selecting the upper level, the print head has no extra nozzle columns.

In a further aspect related to the fourth aspect, a printhead integrated circuit for a fixed pagewidth inkjet printhead is provided, the printhead integrated circuit comprising one or more along a column of nozzles extending longitudinally, wherein each nozzle is configured to emit ink droplets at a plurality of predetermined different point locations along the longitudinal axis, each nozzle having a point location associated therewith, wherein the print The header integrated circuit is configured to compensate for the waste nozzle by printing from a selected functional nozzle located in the same nozzle row as a waste nozzle, the selected functional nozzle being constructed to be associated with the waste The primary point location associated with the nozzle emits at least some of the ink droplets and emits at least some of the ink droplets at its primary point location.

In a fifth aspect, a fixed pagewidth inkjet printhead is provided that includes one or more columns of nozzles extending along a longitudinal axis of the printhead, the printhead comprising a plurality of first And a second opposite end printhead module, the printhead modules being docked across a width of one page, each pair of printhead module pairs defining a common land, one of which spans the bond The nozzle pitch of the zone exceeds a nozzle pitch, and a nozzle pitch is defined as the minimum longitudinal distance between a pair of nozzles in the same nozzle row, and a median of the first pair of adjacent printhead module pairs At least one first nozzle of the first end of the printhead module is configured to emit ink droplets into a respective land.

Selecting the upper ground, at least one second nozzle disposed at the second end of the second print head module of the pair of mating print head modules is configured to emit ink droplets into a respective joint area, The first and second nozzles from the opposing first and second ends of the docked printhead module are caused to eject ink droplets into the common landing zone.

Optionally, each of the first nozzles is configured to emit ink droplets at a plurality of predetermined different point locations along the longitudinal axis, the plurality of different point locations including at least one location within the junction region.

Selecting the upper ground, each of the first and second nozzles is configured to emit ink droplets at respective plurality of predetermined different point locations along the longitudinal axis, each respective plurality of different point locations including at least one point The location is within the junction area.

Selecting the upper ground, a point pitch in the joint zone is substantially equal to a nozzle pitch.

Selecting the upper ground, each of the first and second nozzles is constructed to emit more than one time in one line-time, wherein one line time is defined as a line of printing medium advancing through a line of the printing head Spend time.

Selecting the upper ground, the nozzle disposed adjacent to the first end is configured to emit ink droplets that are skewed toward the first end and the nozzle disposed adjacent to the second end is configured to emit ink that is skewed toward the second end Droplet.

Selecting the upper ground, the degree of skew is related to the distance of each nozzle from the center of the respective print head module, such that the nozzle located near the center of the droplet of the emitted ink is skewed to a lesser extent than the farther from the center. nozzle.

Select the upper ground, the average point pitch is greater than one nozzle pitch.

Selecting the upper ground, the average point pitch is less than 1% larger than the nozzle pitch.

Selecting the upper ground, each nozzle in the print head is constructed to emit ink droplets only at one point unless it is to compensate for a waste nozzle.

In a sixth aspect, a printhead integrated circuit (IC) is provided that includes one or more columns of nozzles extending along a longitudinal axis thereof, the printhead IC having an IC for use with other printheads a first and a second end of the butt joint for defining a one-page wide print head, each nozzle having a primary point position associated therewith, wherein at least one of the first nozzles at the first end is constructed At least some of the ink droplets are emitted at their primary point locations in addition to at least some of the ink droplets that are skewed toward the first end.

Selecting the upper ground, at least one second nozzle at the second end is constructed to emit at least some of the ink liquid that is skewed toward the second end in addition to emitting at least some of the ink droplets at its primary point location drop.

Selecting the upper nozzle, the first nozzle is configured to emit a droplet of ink that is skewed toward the first end and emit an ink droplet at a primary point of its own position in one line time or less, wherein A line time is defined as the time it takes for a column of media to advance through a line of the print head.

Selecting the upper ground, each second nozzle is configured to emit a droplet of ink that is skewed toward the second end and emit an ink droplet at its primary point in one line time or less.

Selecting the upper land, the nozzle pitch of the print head IC is the same as the dot pitch of the printed dots, wherein the nozzle pitch of the print head IC is defined as the longitudinal direction between a pair of nozzles in the same nozzle row The distance and dot pitch are defined as the longitudinal distance between a pair of points within the same print line.

Optionally, the first nozzle is configured to emit at least some of the ink droplets that are skewed toward the first end by a distance between 1 and 3 nozzle pitches.

Optionally, each nozzle row extends between the first land of the first end and the second land of the second end.

The upper and lower lands have a width which is defined as the minimum distance between the edge of the print head IC and a nozzle.

The upper land is selected to have a width between 0.5 and 3.5 nozzle pitch, and the second land has a width between 0.5 and 3.5 nozzle pitch.

When the nozzle printing IC is fixed, the printable area of at least one nozzle row is longer than the longitudinal length of the nozzle row.

In a seventh aspect, a printhead integrated circuit (IC) for a fixed pagewidth printhead is provided, the printhead IC comprising at least one nozzle row extending along a longitudinal axis thereof, wherein The length of a printable area of the nozzle row is longer than the length of the nozzle row.

Preferably, the printable zone has a length that is at least one nozzle pitch longer than the length of the nozzle row, wherein one nozzle pitch is defined as a minimum longitudinal distance between a pair of nozzles in the same nozzle row.

Selecting the upper land, the printable area is up to eight nozzle pitches longer than the nozzle row.

The upper print area is selected, and the printable area corresponds to a dotted line printed by the nozzle row.

The upper printhead is selected to include a plurality of nozzle rows, wherein the printable area corresponds to a length of each nozzle row that is longer than the length of each of the print trains.

Selecting the upper land, the printable area extends beyond each end of the nozzle row.

Selecting the upper ground, at least one first nozzle positioned at a first end of the printhead IC is configured to emit ink droplets that are skewed toward the first end.

Selecting the upper ground, the degree of skew is related to the distance of each nozzle from the first end such that the ink droplets emitted at the nozzle closer to the first end are emitted than the ink positioned at the nozzle remote from the first end The droplets are more skewed towards the first end.

Selecting the upper ground, at least one second nozzle positioned at an opposite second end of the printhead IC is configured to emit ink droplets that are skewed toward the second end.

Selecting the upper ground, the degree of skew is related to the distance of each nozzle from the center of the print head IC, such that the ink droplets emitted at the nozzle closer to the center are smaller than the ink emitted from the nozzles located farther from the center. The droplets are less skewed.

The upper nozzle is selected, and the nozzle located in the central portion of the print head IC is constructed to emit ink droplets substantially perpendicularly with respect to the ink ejection face of the print head IC.

The upper point is selected, and the average point pitch in the printable area is greater than one nozzle pitch.

Selecting the upper ground, the average point pitch is less than 1% larger than the nozzle pitch.

Selecting the upper ground, each nozzle in the print head is constructed to emit ink droplets only at one point unless it is to compensate for a waste nozzle.

In an eighth aspect, a method of controlling the direction of a droplet emerging from an inkjet nozzle includes a nozzle chamber having a top wall having a nozzle opening defined therein And a plurality of movable paddles defining at least a portion of the top wall, each paddle comprising a thermal bending actuator, the method comprising the steps of: actuating the first heat via a respective first drive circuit Bending the actuators such that the respective first paddles are curved toward the bottom wall of the nozzle chamber; actuating the second thermal bending actuators via respective second drive circuits such that the respective second paddles face the bottom of the nozzle chamber Wall bending; and thereby ejecting an ink droplet from the nozzle opening, wherein actuation of the first and second thermal bending actuators is independently controlled via the first and second driving circuits for controlling small The direction in which the droplets exit the nozzle opening.

Selecting the upper ground, the first and second actuators are independently controlled by at least one of: timings of driving signals sent to each of the first and second actuators for providing A coordinated action of the plurality of blades; and power of the drive signals to each of the actuators for causing asymmetric movement of the plurality of blades.

Selecting the upper actuator, if not the first actuator is actuated prior to the second actuator to provide ejection of small droplets in the first direction, ie the second actuator is at the first actuator It was previously actuated to provide small droplets in the second direction.

The upper ground is selected, and if the first actuator is not provided with greater power than the second actuator, the second actuator is provided with greater power than the first actuator.

Selecting the ground, the power of the driving signals is controlled by at least one of: the voltage of the driving signals; and the pulse width of the driving signals.

Selecting the upper ground, two pairs of opposing paddles are provided relative to the nozzle opening.

Selecting the upper ground, the method includes the further step of: actuating a third thermal bending actuator via respective first drive circuits such that the respective third paddles are curved toward the bottom wall of the nozzle chamber; The second drive circuit actuates a fourth thermal bending actuator such that the respective second paddles are curved toward the bottom wall of the nozzle chamber, wherein the first, second, third, and fourth thermal bending actuators The actuators are independently controlled via respective first, second, third and fourth drive circuits for controlling the direction of the droplets emerging from the nozzle opening.

The upper pad is selected and the paddles are movable relative to the nozzle opening.

Selecting the upper ground, each pad defines a portion of the nozzle opening such that the nozzle opening and the paddles are movable relative to the bottom wall.

In a ninth aspect, a method of compensating for a waste nozzle in a fixed pagewidth printhead having one or more nozzle rows extending along a longitudinal axis of the printhead is provided. Each nozzle includes a plurality of thermally curved actuated blades that are configured to emit ink droplets at a plurality of predetermined different point locations along the longitudinal axis, each nozzle having a primary point location associated therewith, The method includes the steps of: identifying the waste nozzle; selecting a functional nozzle in the same nozzle row as the waste nozzle; and emitting at least a selected functional nozzle from the selected functional nozzle at a primary point associated with the waste nozzle Some ink droplets.

Preferably, the method further comprises the step of emitting at least some of the ink droplets from the selected functional nozzle at a primary point location of the selected functional nozzle itself.

Selecting the upper ground, the selected functional nozzle is at a distance of one, two, three or four nozzle pitches from the waste nozzle, wherein one nozzle pitch is defined as a pair in the same nozzle row The minimum longitudinal distance between the nozzles.

Selecting the upper layer, the method further comprises the steps of: advancing a column of printing medium laterally through the line of the stationary printing head during a line time; from the main point position associated with the waste nozzle Selecting a functional nozzle to emit a first ink droplet; and emitting a second ink droplet from the selected functional nozzle at a main point position of the selected functional nozzle itself, wherein the selected The functional nozzle emits the first and second ink droplets during the one line time.

Selecting the upper level, the selected functional nozzles emit the first and second ink droplets in any order.

Optionally, each nozzle can be further configured to emit ink droplets at a plurality of predetermined different point locations along a transverse axis of the printhead.

Selecting the upper layer, the method further comprising the step of: passing a line of printing media laterally through the stationary print head at a rate at which each line advances a line; from the primary point location associated with the waste nozzle Selecting a functional nozzle to emit a first ink droplet; and emitting a second ink droplet from the selected functional nozzle at a main point position of the selected functional nozzle itself, wherein the selected The functional nozzles emit the first and second ink droplets during a period of more than one line time and less than five line times.

The upper nozzle is selected to be identified by detecting the resistance of one or more actuators associated with the waste nozzle.

In a tenth aspect, a method of printing with a dot density exceeding a nozzle density in a fixed page width print head, the fixed page width print head comprising a plurality of end-to-end dockings a printhead integrated circuit across the width of the page, the printhead having at least one nozzle row extending along a longitudinal axis of the printhead, the method comprising the steps of: advancing a line at each line time Rate passing a column of print media laterally through the stationary printhead; ejecting ink droplets from predetermined nozzles in the nozzle row to produce a continuous print line, wherein at least some of the nozzles of the predetermined nozzles, each The ink droplets are emitted at a plurality of predetermined different locations along the longitudinal axis during a line time such that the printed dot density in each of the print lines exceeds the nozzle density.

In an eleventh aspect, an ink jet print head is provided comprising: a substrate comprising a drive circuit layer; a plurality of nozzle assemblies disposed on an upper surface of the substrate and Disposed as one or more nozzle rows extending longitudinally along the print head, each nozzle assembly comprising: a nozzle chamber having a bottom wall defined by the upper surface, a top wall spaced apart from the bottom wall And an actuator for ejecting ink from a nozzle opening defined in the top wall; a nozzle plate extending across the print head, the nozzle plate at least partially defining the top wall; and at least one a conductive trace disposed on the nozzle plate, the conductive trace extending lengthwise along the printhead and parallel to the nozzle rows, wherein the conductive trace extends through the plurality of drive circuit layers and the conductive The conductor posts between the traces are connected to a common reference plane in the drive circuit layer.

Selecting the ground, the common reference plane defines a ground plane or power plane.

Optionally, the printhead includes at least one first conductive trace, wherein the first conductive trace is directly connected to a plurality of actuators in at least one nozzle row adjacent the first conductive trace.

Optionally, the printhead further includes at least one second conductive trace that is not directly connected to any of the actuators.

Optionally, the first conductive trace extends continuously along the printhead to provide a common reference plane for each actuator in the nozzle train.

Optionally, the first conductive trace extends discontinuously along the printhead to provide a common reference plane for a set of actuators in the nozzle train.

Selecting the upper ground, the first conductive trace is disposed between respective nozzle row pairs, the first conductive trace providing a common reference plane for the plurality of actuators in the two nozzle rows of the pair of nozzle rows .

Selecting the ground, each actuating has a first terminal directly connected to the first conductive trace and a second terminal connected to a driving transistor in the driving circuit layer.

Selecting a ground, each top wall including at least an actuator and the first terminal of each actuator being coupled to the first connector via a transverse connector extending transversely across the nozzle plate relative to the first conductive trace A conductive trace.

Selecting the upper ground, the second terminal is connected to the driving transistor via an actuator post extending between the driving circuit layer and the second terminal.

The upper actuator is selected to be perpendicular to the plane of the first conductive trace.

Selecting the upper floor, each top wall comprising at least one movable paddle comprising a respective thermal bending actuator movable toward the bottom wall of the respective nozzle chamber to cause ink to exit from the nozzle opening, wherein The thermal bending actuator includes: an upper thermoelastic beam having the first and second terminals; and a lower passive beam welded to the thermoelastic beam such that when current passes through the thermoelastic beam, the heat The resilient beams extend relative to the passive beam causing the respective paddles to flex toward the bottom wall of the nozzle chamber.

Selecting the upper ground, the thermoelastic beam is coplanar with the conductive trace.

Selecting the upper layer, the thermoelastic beam and the conductive trace comprise the same material.

The upper nozzle is selected and the nozzle plate contains a ceramic material.

Selecting the upper layer, the driver circuit layer includes a driving field effect transistor (FET) for each actuator, each driving FET including a gate for receiving a logic transmission signal, and one electrically connected to the power plane a source, and a drain in electrical communication with the ground plane, the drive FET being one of: a pFET, wherein the actuator is coupled between the drain and the ground plane; or an nFET, wherein The actuator is coupled between the power plane and the source.

Selecting the ground, the drive FET is a pFET and the first conductive trace provides the ground plane, and wherein the first terminal of the actuator is coupled to the first conductive trace and the second terminal of the actuator is Connect to the drain of the pFET.

Selecting the ground, the second conductive trace provides the power plane and is connected to the source of the pFET.

Selecting the ground, the drive FET is an nFET and the first conductive trace provides the power plane, and wherein the first terminal of the actuator is connected to the first conductive trace and the second terminal of the actuator is connected To the source of the nFET.

Selecting the ground, the second conductive trace provides the ground plane and is connected to the drain of the nFET.

In a twelfth aspect, a printhead integrated circuit (IC) for an ink jet print head is provided, the print head integrated circuit comprising: a substrate comprising a drive circuit layer: a nozzle assembly disposed on an upper surface of the substrate and configured as one or more nozzle rows extending longitudinally along the printhead IC, each nozzle assembly comprising: a nozzle chamber having a a bottom wall defined by the upper surface, a top wall spaced apart from the bottom wall, and an actuator for ejecting ink from a nozzle opening defined in the top wall; an extension across the print head a nozzle plate of the IC, the nozzle plate at least partially defining the top walls; and at least one conductive trace fused to the nozzle plate, the conductive trace extending lengthwise along the print head and parallel to the nozzles a column, wherein the conductive trace is connected to a common reference plane in the driver circuit layer via a plurality of conductor posts extending between the driver circuit layer and the conductive trace.

Selecting the ground, the common reference plane defines a ground plane or power plane.

The upper conductive layer is selected above or below the nozzle plate.

Process for an ink jet nozzle assembly including a movable top wall paddle For the sake of completeness and as a background of the invention, an ink jet for manufacturing a movable top wall paddle having a thermal bending actuator The process of the nozzle assembly (or "nozzle") will now be described. The complete inkjet nozzle assembly 100 shown in Figures 15 and 16 utilizes a thermal bending actuator whereby the movable paddles 4 in the top wall of a nozzle chamber are bent toward the substrate 1 causing ink to be ejected. result. This process is described in the Applicant's earlier U.S. Patent Application Publication No. 2008/0309,728, the disclosure of which is incorporated herein by reference. However, it will be appreciated that corresponding processes can be used to fabricate any of the inkjet nozzle assemblies described herein, as well as printhead and printhead integrated circuits (ICs).

The starting point for MEMS fabrication is a standard CMOS wafer having a CMOS driver circuit disposed in the upper layer of a passivated germanium wafer. At the end of the MEMS process, the wafer is divided into individual print head integrated circuits (ICs), each of which includes a CMOS drive circuit layer and a plurality of nozzle assemblies.

In the sequence of steps shown in Figures 1 and 2, an 8 micron layer of ruthenium dioxide is deposited on the upper surface of the substrate 1. The depth of the ceria layer defines a depth for the nozzle chamber 5 of the inkjet nozzle. After depositing the cerium oxide (SiO ₂ ) layer, it is etched to define the wall 4 which will become the sidewall of the nozzle chamber 5, as shown in FIG.

As shown in Figures 3 and 4, the nozzle chamber 5 is filled with a photoresist or polyimine 6 which functions as a stent for the sacrificial nature of subsequent deposition steps. The polyimine 6 is spin coated onto the wafer using standard techniques, UV hardening and/or hard bake, and then subjected to a chemical mechanical planarization (CMP) treatment on the ceria wall 4 Stop at.

In Figures 5 and 6, the top wall 7 of the nozzle chamber 5 is formed, and the highly conductive actuator column 8 extending down to the electrode 2 is also formed. Initially, a 1.7 micron layer of cerium oxide was deposited on the polyimide and wall 4. This ruthenium dioxide layer defines the top wall 7 of the spray booth chamber 5. Next, a pair of vias are formed in the wall 4 by using standard anisotropic DRIE, reaching down to the electrodes 2. This etching exposes the pair of electrodes 2 through the respective via holes. Next, the via holes are filled with a highly conductive metal, such as copper, by using electroless plating. The deposited copper posts 8 are subjected to a CMP process which is stopped at the top wall member 7 of the ceria to provide a flat structure. The copper actuator posts 8 formed during electroless copper plating meet the respective electrodes 2 to provide a linear conductive path up the top wall 7.

In Figures 7 and 8, the metal pad 9 is formed by depositing and etching a 0.3 micron aluminum layer. Any highly conductive metal (e.g., aluminum, titanium, etc.) can be used and should be deposited to a thickness of about 0.5 microns or less to not affect the overall flatness of the nozzle assembly. The metal pad 9 is defined by the etching for being disposed on the actuator post 8 and the top wall member 7 in a predetermined 'bending region' of the thermoelastic active beam member. It will be appreciated that the metal pads 9 are not absolutely indispensable and the steps shown in Figures 7 and 8 can also be removed from the process.

In Figures 9 and 10, a thermoelastic active beam member 10 is formed on the ceria top wall 7. Due to the relationship being welded to the active beam member 10, a portion of the ceria top wall 7 acts like a lower passive beam member of a mechanical thermal bending actuator, the mechanical thermal bending actuator being driven by the active The beam 10 and the passive beam 16 are defined. The thermoelastic active beam member 10 can comprise any suitable thermoelastic material such as titanium nitride, titanium aluminum nitride, and aluminum alloy. Vanadium-aluminum alloys are preferred as described in U.S. Patent Application Serial No. 11/607,976, the entire disclosure of which is incorporated herein by reference. The material has advantageous properties such as high thermal expansion, low density, and high Young's modulus.

To form the active beam member 10, a 1.5 micron active beam material layer was initially deposited by standard PECVD. The beam material is then etched using standard metal etching to define the thermoelastic active beam member 10. After the metal etching is completed, as shown in FIGS. 9 and 10, the thermoelastic active beam member 10 includes a portion of the nozzle opening 11 and a meandering beam member 12, the two ends of which are electrically connected to each other via the actuator column 8 to Power and ground electrode 2. The flat beam member 12 extends from the top of a first (power) actuator post and is bent about 180 degrees to return to the top of a second (grounded) actuator post.

Still referring to Figures 9 and 10, the metal pads 9 are arranged to facilitate current flow in the region of higher resistance. A metal pad 9 is disposed in the bend region of the beam member 12 and is sandwiched between the active beam member 10 and the passive beam member 16. Other metal pads 9 are disposed between the top of the actuator post 8 and the end of the beam member 12.

Referring to Figures 11 and 12, the ceria top wall 7 is then etched to define a complete nozzle opening 13 and a movable cantilever blade 14 in the top wall. The paddle 14 includes a thermal bending actuator 15 which itself is comprised of the active thermoelastic beam member 10 and the underlying passive beam member 16. The nozzle opening 13 is defined in the paddle 14 of the top wall such that the nozzle opening moves with the actuator during actuation. The configuration in which the nozzle opening 13 is stationary with respect to the paddle 14 can be the same as that described in the applicant's U.S. Patent Application Serial No. 11/607,976.

A peripheral space or gap 17 around the movable paddle 14 separates the paddle from a stationary portion 18 of the top wall. This gap 17 allows the movable paddle 14 to flex into the nozzle chamber 5 and towards the substrate 1 during actuation of the actuator 15.

Referring to Figures 13 and 14, a polymer layer 19 is then deposited over the entire nozzle assembly and etched to redefine the nozzle opening 13. The polymer layer 19 can be protected by a thin, removable metal layer (not shown) prior to etching the nozzle opening 13, as described in US Publication No. 2008/0225077, the disclosure of which is incorporated herein by reference. Was included in this article.

The polymer layer 19 has several functions. First, it fills the gap 17 to provide a mechanical seal between the paddle 14 and the stationary portion 8 of the top wall 7. As long as the polymer has a low Young's modulus, the actuator can still bend toward the substrate 1 while preventing ink from escaping from the gap 17 during actuation. Second, the polymer is highly hydrophobic, which minimizes the possibility of ink flowing out of the relatively hydrophilic nozzle chamber and onto the inkjet face of the printhead. Third, the polymer acts like a protective layer, which facilitates maintenance of the printhead.

The polymer layer 19 may comprise a polymerized decane, such as, for example, polydimethyl methoxy oxane (PDMS) or any polymer from the family of polydimethyl siloxanes, as described in the U.S. patent. In the application No. 12/508,564, the contents of the disclosure are hereby incorporated by reference. The polysesquioxanes typically have the experimental formula of (RSiO _1.5 ) _n where R is hydrogen or an organic group and n is an integer which represents the length of the polymer chain. The organic group may be a C _1-12 alkyl group (e.g., a methyl group), a C _1-10 aromatic hydroxy group (e.g., a phenyl group) or a C _1-16 aralkyl group (e.g., a benzyl group). The polymer chain can be of any length known in the art (e.g., n is from 2 to 10,000, 10 to 5,000, or 50 to 1000). Specific examples of suitable polydimethyl siloxanes are poly(methylsesquioxanes) and poly(phenylsesquioxanes).

Returning to the final fabrication steps shown in Figures 15 and 6, an ink supply channel 20 is etched through the back side of the substrate to the nozzle chamber 5. Although the ink supply passage 20 shown in Figs. 15 and 16 is aligned with the nozzle opening 13, it may be disposed to be offset from the nozzle opening.

After etching the ink supply passage, the polyimine 6 filled into the nozzle chamber 5 is washed by plasma (front side plasma cleaning or back side plasma cleaning) using, for example, oxygen plasma. It is removed to provide the nozzle assembly 100.

Inkjet nozzle assembly with opposed movable top wall paddle pairs

As shown in FIG. 12, the inkjet nozzle assembly previously described by the Applicant of the present application includes a movable paddle 14 for ejecting ink through the nozzle opening 13.

Referring now to Figure 17, an ink jet nozzle assembly 200 including a pair of opposed top wall blades 14A and 14B is shown in plan view. In all of the ink jet nozzles described herein in plan view, the upper polymer layer 19 is removed for clarity. Also, for the sake of clarity, features that are common to all of the inkjet nozzles described herein are labeled with similar reference numerals.

Each of the blades 14A and 14B has its own thermal bending actuators 15A and 15B defined by upper thermoelastic beams and lower passive beams in the same manner as the above-described inkjet nozzles 100. Also, each of the thermal bending actuators (and each of the blades) can be independently controlled via respective driving circuits in the CMOS driving circuit layer of the substrate 1. This allows the first actuator 15A (and the first paddle 14A) to be controlled independently of the second actuator 15B (and the second paddle 14B).

Figure 17 shows a nozzle assembly 200 having opposing paddles 14A and 14B, each paddle defining a portion of the nozzle opening 13. Thus, the nozzle opening 13 will move with the paddle during actuation.

Figure 18 shows another nozzle assembly 210 having opposing paddles 14A and 14B, each paddle being movable relative to the nozzle opening 13. In other words, the nozzle opening 13 is defined in the non-moving portion of the top wall 7. It will be appreciated that the nozzle assemblies 200 and 210 illustrated in Figures 17 and 18 are all within the scope of the present invention.

Figure 19 shows a simplified circuit diagram for controlling the relative charge of each of the actuators 15A and 15B supplied to the nozzle assembly 200. The actuator 15A receives the full amount of power, and the amount of power supplied to the actuator 15B is changed using the potentiometer 202.

Experimental measurements using a different set of potentiometer resistances show that different maximum paddle speeds can be achieved by reducing the amount of power supplied to the actuator 15B. For example, at the same amount of power, the maximum paddle speeds are approximately equal. However, when the potentiometer resistance value is increased, the maximum paddle speed of the paddle 14B is significantly reduced relative to the paddle 14A. For example, the maximum paddle speed of paddle 14B can be reduced to 75% lower, 50% lower, or 25% lower than the maximum paddle speed of paddle 14A.

This difference in maximum paddle speed has a major impact on the direction of the drop. Therefore, by controlling the relative amount of electric power supplied to each of the actuators 15A and 15B, the direction of the small droplets ejected from the nozzle opening 13 can be controlled. Experimentally, the direction of the droplets can be skewed up to a 4-point pitch of a printed page. Therefore, the pitch of -4, -3, -2, -1, 0, +1, +2, +3, and +4 points (and all intermediate non-integer point positions) can be achieved by a nozzle, where ' 0' is defined as the primary point location resulting from the ejection of small droplets perpendicular to the inkjet face. This result has important ramifications for the design of pagewidth inkjet printheads, which will be discussed in more detail below.

Of course, for experimental purposes, the use of potentiometer 202 allows a range of power parameters to be conveniently investigated. However, skewed droplet ejection can also be achieved by controlling the timing of actuation, which can be used as an alternative or an additional method of controlling the amount of power supplied to each actuator. For example, actuator 15A can accept its actuation signal before or after actuator 15B receives its actuation signal, producing a result of asymmetric paddle motion and skewed droplet ejection.

Also, the amount of power supplied to each actuator can be controlled by changing the pulse width of the drive signal. This method of changing the amount of power supplied to each actuator is most feasible using a CMOS driver circuit, especially in the example where it is desired to quickly change the direction of the droplets.

Inkjet nozzle assembly with four movable top wall blades

The nozzle assemblies 200 and 210 shown in Figures 17 and 18 allow the direction in which the droplets are ejected to be controlled along an axis. Typically (and most usefully), the axis will be the longitudinal axis of an elongated page-width printhead along which the nozzle array extends. However, further control of the direction of the droplets can be achieved by using more than two paddles that are configured relative to the nozzle opening.

20 shows a portion of a printhead that includes a nozzle assembly 220, each nozzle assembly 220 including four movable paddles 14A, 14B, 14C, and 14D that are configured relative to the stationary nozzle opening 13. Damping posts 221 projecting from the side walls of the nozzle chamber provide assistance in controlling droplet ejection characteristics and chamber refilling, particularly when one of the actuators is deactivated.

In the four-blade configuration shown in Figure 20, the droplet ejection can be skewed along an axis or two axes (i.e., the longitudinal axis and the transverse axis) by the coordinated movement of the four blades. Thus, an ink droplet can be directed anywhere on a two-dimensional area of a column of printing medium, typically a circular or elliptical region centered at the center of the firing nozzle.

Figure 21 shows a portion of a nozzle array having a plurality of nozzles 220 spaced apart from one another by a nozzle pitch along the longitudinal axis of the nozzle array. An elliptical region 222 of a row of print media shows a region of the firing nozzle ('0') at the center of the elliptical region from which ink droplets can be ejected. As seen in Fig. 21, the firing nozzle ('0') can emit ink droplets at any point within the two-dimensional elliptical region 222.

The ability to emit ink droplets along a transverse axis (i.e., perpendicular to the longitudinal nozzle column axis) means that small droplet ejections from the nozzle assembly 220 need not be strictly synchronized with other nozzles in the same nozzle column. . Typically, all of the firing nozzles in the pagewidth printhead must be emitted during a line-time period defined as a series of prints advancing laterally through a line of the print head. Spend time. However, an emission nozzle having the ability to emit ink droplets along the transverse axis of the printhead can be constructed to emit an ink droplet before or after a line of print has passed the nozzle and still The ink droplets are printed onto the same printed line. Accordingly, the nozzle assembly 220 allows the design of the pagewidth printhead to be more resilient than the nozzle assemblies 200 and 210.

In addition, multiple top wall blades can increase the overall injection power available for each nozzle. Therefore, the design of the four-blade nozzle is more suitable for the injection of viscous fluid than the design of the two-blade nozzle or the single-blade nozzle. Similarly, the design of the two-blade nozzle is more powerful than the design of the single-blade nozzle.

The power of each individual actuator can also be increased by increasing the length of the actuator beam and/or providing an actuator beam having multiple turns. The actuator beam of the crucible is described in the applicant's U.S. Patent No. 7,611,225, the disclosure of which is incorporated herein by reference. Accordingly, the present invention also provides a high power inkjet nozzle suitable for injecting fluids having relatively high viscosities (e.g., higher viscosity than water).

Inkjet print head with high dot density

In a typical pagewidth printhead, each firing nozzle (i.e., the nozzle selected to emit, by which the data received by the printhead is printed) is only fired once in a line time. Again, each nozzle ejects an ink droplet such that the droplet falls at a primary point location associated with the nozzle. When a nozzle strikes a primary point location associated therewith, the droplet ejection is typically perpendicular to the inkjet face of the printhead. Thus, in a conventional pagewidth printhead, the nozzle density of the printhead corresponds to the dot density on the page being printed. For example, a page width printhead with a nozzle pitch of n will print a line with a pitch of n, where the nozzle pitch and point pitch are defined as the center of adjacent nozzles and points, respectively. the distance between.

However, the nozzle assemblies 200, 210 and 220 allow the print head to be designed such that the printed dot pitch is less than the nozzle pitch of the print head, so that the density of the printed dots is greater than the nozzle density of the print head .

Figure 22 shows a portion of a one-page wide printhead 230 in which the pitch of the printed dots is less than the nozzle pitch of the printhead. Three nozzles 231 in the same nozzle row are shown and are separated by a nozzle pitch n. Each of the three nozzles can be constructed, for example, by the nozzle assembly 210 (shown in Figure 18). Ink droplets from each nozzle can be incident on a line of print media 235 at a plurality of different point locations along the longitudinal axis indicated by arrow 236. As shown in Figures 22, 23, 29 and 30, the print medium 235 is fed out of the sheet of paper (i.e., toward the viewer and across the longitudinal axis of the printhead or printhead IC).

Still referring to Fig. 22, each nozzle 231 is constructed to eject ink at two different point locations during a line time - a point position is the primary point position resulting from the ejection of small droplets perpendicular to the surface of the print head. Another point position 234 is obtained by a skewed ink jet that drops ink droplets halfway between the major point locations. The resulting point pitch d is thus less than the nozzle pitch n such that the density of the printed dots is greater than the density of the nozzles of the print head.

In the example shown in Fig. 22, the nozzle pitch n is twice the dot pitch d, but it will be understood that the print head can construct a nozzle pitch n and a dot pitch d of n>d. Any ratio. For example, if each nozzle is printed at its main point position and two other point positions (eg, on both sides of the main point position) within one line time, the print with a dot pitch of n=3d can be used. Was reached.

The actual point pitch that can be achieved is limited only by the ink chamber refill rate relative to the rate at which the print medium is fed through the print head. The applicant's model shows that at 60 pages per minute, the ink chamber can be refilled twice in a line time to achieve a dot density of twice the dot density typically achieved with a typical non-moving pagewidth printhead. Print. Of course, slowing down the rate at which the print media feeds (e.g., to 30 ppm) can achieve higher dot densities.

In this way, the immovable pagewidth printhead achieves versatility similar to a scanning printhead. In a scanning printhead, the density of printed dots can be increased by printing at a lower speed because the scanning head sweeps across each line and has a chance to vary in many different ways depending on the scanning speed. The location of the point is printed. Although printed at a much higher speed than the speed of a conventional scanning type print head, the fixed page width print head 230 shown in Fig. 22 has similar versatility and can be extremely high. Density (eg, 3200 dpi) to print.

Waste nozzle compensation

The applicant of the present application has previously described a mechanism for waste nozzle compensation in a stationary pagewidth printhead. As used herein, 'dead nozzle' means a nozzle that does not emit any ink, or a nozzle that injects ink with insufficient droplet velocity or droplet direction. Usually the 'waste nozzle' is caused by an actuator failure (which is the fastest way to find the nozzle failure with the detection circuit), but it can also be caused by an unobstructed blockage in the nozzle opening. Or caused by the ink jet surface obstructing or partially obstructing the unremovable debris of the nozzle opening.

Typically, waste nozzle compensation in a stationary pagewidth printhead requires printing from a redundant nozzle column (as described in U.S. Patent Nos. 7,465,017 and 7,252,353, the contents of each of which are hereby incorporated by reference. Was included in this article). The disadvantage is that the print head requires extra nozzle rows, which can disadvantageously increase the cost of the print head.

Alternatively, the visual effect of a waste nozzle can be compensated by firing (preferably 'overpowering') a nozzle adjacent to the waste nozzle (as described in U.S. Patent No. 6,757,549, the patent The content is hereby incorporated by reference. In fact, this involves a modification of the print mask that minimizes the overall visual effect of the waste nozzle.

The inkjet nozzle assemblies 200, 210, and 220 can implement waste nozzle compensation without the need for redundant nozzle rows or changing the print mask. Figure 23 shows a portion of a one-page wide printhead 240 in which a waste nozzle 242 is compensated by an adjacent functioning nozzle 243 located in the same nozzle row.

There are three nozzles in the same nozzle array, each nozzle being constituted by a nozzle assembly 210 (shown in Figure 18). The central nozzle 242 is a waste nozzle or a malfunctioning nozzle, and adjacent nozzles 243 and 244 on both sides of the central nozzle 242 are functionally normal nozzles.

Ink droplets from each of the functional nozzles 243 and 244 can be directed (to be fed in the direction toward the viewer when viewing Figure 23) a plurality of different prints 235 along the longitudinal axis 236. Point location. During a line time, the nozzle 243 emits an ink droplet at its own primary point location 247 and at a primary point location 248 associated with the waste nozzle 242. Therefore, the nozzle 243 compensates the waste nozzle 242 in the same nozzle row by printing two points during one line time. Of course, in the next line time, the nozzle 244, rather than the nozzle 243, compensates for the waste nozzle 242 such that the nozzles 243 and 244 share the workload of the waste nozzle. Again, the compensating nozzle need not be in close proximity to the waste nozzle, depending on the extent to which the slanted droplet ejection can be achieved. For example, the compensating nozzle can be located at a distance of -4, -3, -2, -1, +1, +2, +3, and +4 nozzles from the waste nozzles, allowing many different nozzles to share one The working load of the waste nozzle.

Figure 23 shows a scheme in which nozzle 243 is required to eject an ink droplet at its own primary point location 247 and at a primary point location 248 associated with the waste nozzle 242 during a line time period. Of course, the print mask is primarily to control which ones are required to be fired within a particular line time, and then a suitable functional nozzle is given priority for compensation if the functional nozzle is not at that particular If ink is emitted at its main point position within one line time. Selecting a compensating nozzle in this manner can further minimize the need for a functional nozzle near a waste nozzle. In many cases and in connection with the printing mask, it is possible to avoid a compensating nozzle being required to fire twice in one line time.

Alternatively, a printhead formed by nozzle assembly 220 may not necessarily emit a compensating nozzle to perform the waste nozzle compensation during the same line time as the waste nozzle is fired. Since the nozzle assembly 220 can emit ink droplets to any point location of a two-dimensional area including the position of the point along the transverse axis of the print head, the compensation of the waste nozzle can be extended to a little The post line time is either advanced to the earlier line time. This makes the choice of compensating nozzles more flexible on time.

Waste nozzles are typically identified by detecting one or more point resistance values of actuators corresponding to the spent nozzles. The advantage of this method is the ability to dynamically dispense and compensate for waste nozzles. However, other methods for finding waste nozzles (e.g., optical techniques using predetermined print patterns) can also be used.

Page width print head with seamless joint

Excluding a monolithic pagewidth printhead with very low wafer yield, the pagewidth printhead of the present invention docks multiple printhead ICs in an end-to-end manner across the page width together.

Figure 24 shows five configurations of printhead ICs 251A-E that are end-to-end opposite to form a one-page wide printhead 250, and a single printhead IC 251 is shown in Figure 25. It will be appreciated that longer pagewidth printheads (e.g., A4 printheads and wide format printheads) can be fabricated by butting more printhead ICs 251 together. The docking of the print head ICs in this manner has the advantage of minimizing the width of the print area, which eliminates the need for precise alignment between the print medium and the print head. However, referring to Figures 26 and 27, the printhead ICs that are docked together have a disadvantage in that printing across the land 257 between pairs of butt-printing head ICs is difficult. This is because the nozzles 255 cannot be fabricated very close to the edge 258 of each of the print head ICs - for structural reinforcement and to allow the print head ICs to be docked together, an unavoidable 'dead space' 259 Must be left at the edge. Thus, the actual nozzle pitch between the mating ICs is inevitably greater than one nozzle pitch in a nozzle row of a row of printhead ICs.

Therefore, the pagewidth printhead must be designed to seamlessly print ink dots across the land. Referring again to Figures 24 through 27, the applicant of the present application has described above a solution to the problem of constructing a pagewidth printhead in a manner that interfaces the printhead IC. As shown in Figure 27, a displaced nozzle triangle 253 effectively fills the gap between the nozzles from adjacent butt header ICs. By adjusting the timing of the emission of the nozzles 255 within the shifted triangle 253 (i.e., by emitting the nozzles at a later time point than their corresponding nozzle columns), the dots can be seamlessly printed across The junction area 257. The effect of the displaced nozzle triangle 253 is described in detail in U.S. Patent Nos. 7,390,071 and 7,290, 852, the disclosure of each of each of each

Figure 27 also shows the adhesive pad 75 and alignment reference point 76 disposed along the longitudinal edges of the printhead IC. Bond pads 75 are connected by wirebonds (not shown) for providing power and logic signals to the CMOS driver circuitry within the printhead IC. Aligning the fiducials 76 allows the docked printhead ICs to be aligned with each other during construction of the printhead using a suitable optical alignment tool (not shown).

While this displaced nozzle triangle 253 provides a suitable solution to the problem of printing across the land, there are still several problems. First, the shifted triangle 253 is required to be supplied with ink, and a sharp kink extending longitudinally in the ink supply conduit on the back side adversely affects the supply of ink to the nozzles within the triangle 253. Second, the shifted nozzle triangle 253 reduces the wafer yield because it increases the width of each of the print head ICs 251; each print head IC must have a width sufficient to accommodate r + 2 nozzle columns, even if printed The head IC has only r nozzle rows as well.

The nozzle assemblies 200, 210, and 220 described herein have the ability to eject ink droplets at a plurality of predetermined different point locations along a longitudinal axis, so that the problem of docking the print head ICs together can be A solution is provided and a fixed point pitch can be maintained across each land. Further, as shown in Fig. 28, the print head IC 260 having the nozzle rows which are not interrupted (i.e., the nozzle triangles 253 which are not displaced as shown in Fig. 27) can be butted together. The design of this printhead IC not only facilitates the supply of ink along the nozzle column, but also increases wafer yield. In principle, there are two ways to compensate for the 'absent' nozzle zone across the landing zone 257.

In the first mode, the nozzles disposed at both ends of the print head IC 260 are constructed to emit ink droplets that are skewed toward the respective ends, and the nozzles disposed at the central portion of the print head IC 260 are ejected. A small droplet of ink perpendicular to the inkjet face. Referring to Figure 29, a row of printhead ICs 260 is shown in which nozzles 264 disposed on the right hand side are constructed to eject ink droplets that are skewed toward the right hand side. Similarly, the nozzle 262 disposed on the left hand side is constructed to eject ink droplets that are skewed toward the left hand side. A nozzle 266 disposed at a central portion of the printhead IC is constructed to eject ink droplets perpendicular to the ink ejection face. Although the nozzles 262, 264, and 266 have different small droplet ejection characteristics, these nozzles are the same in terms of the nozzle type shown in Figs. 18, 19 or 20 having the ability to control the direction of the small droplets. of.

The degree of skew is related to the distance of a particular nozzle from the center of the printhead IC 260. A nozzle positioned at the end of the printhead IC is constructed to eject a skewed droplet of ink that is skewed to a greater extent than a droplet of ink ejected from a nozzle disposed in the center of the printhead IC. A horn-like deployment from the center of the printhead IC 260 to the outside allows the uniform dot pitch to be maintained over the entire length of the printhead IC.

Although the 'horn type flaring' of the small droplet ejection is slightly exaggerated in FIG. 29, it can be understood that the average dot pitch of the injected ink droplets is due to this horn type. The relationship of the expansion is slightly larger than the nozzle pitch of the print head IC 260. However, since there are hundreds or thousands of nozzles in each nozzle row, the dot density is negligible with respect to the nozzle density. Typically, despite the flared droplet ejection, the average dot pitch is still less than 1% greater than the nozzle pitch of the printhead.

Due to the skewed droplet ejection relationship at the edge of the printhead IC 260, the actual printable area of a particular nozzle row is longer than the length of the nozzle array. The printable area can be from 1 to 8 nozzle pitches longer than the nozzle row. The elongated printable area allows the printhead IC to be printed into the land 257 between the butted printhead ICs 260, thereby eliminating the shifted nozzles shown in FIG. Triangle 253.

Of course, it is also possible to have only a small droplet ejection having a skew at the nozzle located at one end of the print head IC. However, given the width of a typical land 257 (i.e., the width between one of the nozzle rows of the opposite nozzle row in the same nozzle row), there is a flare-type expansion as shown in FIG. A configuration of small droplet ejection is preferred. This may include a 'none' nozzle zone within the land 257 that can be compensated for by the mating head IC pair.

The print head IC 260 having the flare-type expanded droplet ejection shown in Fig. 29 has the advantage that, in the absence of waste nozzle compensation or printing at a higher dot density, each nozzle is Only one time is emitted during one line time, while the length of the printable area is expanded to be greater than the length of a corresponding nozzle row. In another mode, a row of printhead ICs 270 can be constructed with the selected nozzles at the end of each nozzle row being fired more than once in a line time to compensate for 'no' in the joint zone. Nozzle zone.

Referring to Figure 30, a printhead IC 270 is shown in which most of the nozzles eject ink droplets perpendicular to the ink ejection face of the printhead IC. However, at least one nozzle 272 at the end of a nozzle row is configured to eject an ink droplet at a primary point location 274 (ie, perpendicular to the inkjet surface) and to eject an ink droplet at the secondary point location. 276 is skewed toward the respective ends of the print head IC. In other words, the nozzle 272 is configured to eject two drops of ink droplets in one line time in a manner similar to the nozzles 231 in the high density printhead 230. However, the nozzles 272 maintain a uniform point pitch d such that the nozzle pitch n is typically equal to the point pitch d throughout the printable area of the printhead IC 270.

While the advantage of the printhead IC 270 is that the dot pitch is not sacrificed relative to the nozzle pitch, it has the disadvantage that the nozzle 272 at the end of each nozzle row must emit ink twice as often as the other nozzles 271. Therefore, the nozzle 272 is more likely to malfunction due to fatigue, so the print head IC 260 is preferable for the print head ICs that are butted together.

Improved MEMS/COMS integration

An important aspect of MEMS printhead design is the integration of MEMS actuators with the underlying CMOS driver circuitry. In order for nozzle actuation to occur, the current from the drive transistor in the CMOS must flow upward into the MEMS layer, through the actuator and down to the CMOS drive circuit layer (eg, back to the ground plane of the CMOS layer) . Since there are thousands of actuators in a single printhead IC, the efficiency of the current flow path should be maximized to minimize the loss of overall printhead efficiency.

To date, the applicant of the present application has described a nozzle assembly having a pair of straight posts extending between a MEMS actuator positioned in the top wall of the nozzle chamber and a bottom CMOS drive circuit layer. The manufacture of such parallel actuator columns is illustrated in Figures 5 and 6, and is described herein. Contrary to the tortuous current path, straight copper posts that extend up to the MEMS layer have been shown to improve printhead efficiency. However, the electrical efficiency of the applicant's MEMS printhead (and printhead IC) is still improved.

One problem associated with the use of a common CMOS power plane and ground plane to control thousands of actuators is known as 'ground bounce'. Ground bounce is a well-known problem in integrated circuit design, which is exacerbated in the case where a large number of devices are powered between a common power plane and a ground plane. Ground bounce is usually a description of an unwanted voltage drop across a power plane or ground plane, which can occur for a number of different reasons. Typical causes of ground bounce include: series resistance ("IR drop"), self-inductance, and mutual inductance between the ground plane and the power plane. Any of these phenomena can cause ground bounce due to undesired reduction of the potential difference between the ground plane and the power plane. This reduced potential difference inevitably causes a drop in the electrical efficiency of the integrated circuit (more specifically, the print head IC in this example). It will be appreciated that the configuration and configuration of the ground plane and power plane, as well as the connections to them, will fundamentally affect the overall efficiency of the ground bounce and print head.

Referring to Figure 31, a plan view of a portion of a printhead IC 300 is shown, wherein the printhead IC has conductive traces extending longitudinally and parallel to the ejection train. In Figure 31, the uppermost polymer layer 19 has been removed for clarity.

A plurality of nozzles 210 (which have been described in detail with reference to Figure 18) are disposed in a nozzle row that extends along the longitudinal axis of the IC 300. Figure 31 shows a pair of nozzle rows 302A and 302B. Of course, the printhead IC 300 can include more spray columns. Nozzle columns 302A and 302B are paired and offset from one another, with nozzle column 302a being negatively responsible for printing an 'even' point and another nozzle column 302B being responsible for printing an 'odd number'. In the print head of the applicant of the present application, the nozzle rows are typically paired in this manner and can be seen more clearly in, for example, Figure 28.

A first conductive trace 33 is disposed between the nozzle columns 302A and 302B. The first conductive trace 303 is deposited on the nozzle plate 304 of the printhead IC 300 (which defines the nozzle chamber top wall 7 (see Figure 10)). Thus, the first conductive trace 303 and the thermoelastic beam 10 of the actuator 15 are substantially coplanar and can be formed during MEMS fabrication by co-deposition with the thermoelastic beam material (eg, vanadium aluminum alloy). The conductivity of the conductive traces 303 can be further improved by depositing another layer of conductive metal (e.g., copper, titanium, aluminum, etc.) during MEMS fabrication. For example, it will be appreciated that a metal layer can be deposited prior to deposition of the thermoelastic beam material (e.g., deposited with the metal pad 9 shown in Figure 8). A simple modification of the etch mask for the metal pad 9 can be used to define the conductive traces 303. Thus, conductive traces 303 can include multiple layers of metal to optimize conductivity.

Each actuator 15 has a first terminal that is directly connected to the first conductive trace 303 via a lateral connector 305. As seen in FIG. 31, each actuator from both nozzle rows 302A and 302B has a first terminal connected to the first conductive trace 303. The first conductive trace 303 is connected to a common within the underlying CMOS drive circuit layer via a plurality of conductor posts 307 (which are fabricated similarly to the actuator post 8 described above with reference to FIG. 6) Reference plane. Thus, the conductive traces 303 can extend continuously along the printhead IC 300 to provide a common reference plane for each of the pair of nozzle rows. As will be described in greater detail below, the common reference plane between nozzle columns 302A and 302B can be a power plane or a ground plane, which is used in the CMOS driver circuit as an nFET or pFET. related.

Alternatively, the conductive traces 303 may extend discontinuously along the printhead IC 300, each portion of the conductive traces providing a common reference plane for a set of actuators. In the case where peeling of the conductive traces would be a problem, although the conductive traces still function in the manner described above, a discontinuous conductive trace 303 is preferred.

A second terminal of each actuator 15 is coupled to a bottom drive FET within the CMOS drive circuit layer via an actuator post 8 extending between the actuator and the CMOS drive circuit layer. Each actuator post 8 is completely similar to the actuator post 8 shown in Figure 6 and is formed in this manner during MEMS fabrication. Therefore, each of the actuators 15 is independently controlled by the respective drive FETs.

In FIG. 31, a pair of second conductive traces 310A and 310B also extend lengthwise along the printhead IC 300 and on the flanks of the pair of nozzle rows 302A and 302B. The second conductive traces 310A and 310B are complementary to the first conductive trace 303. In other words, if the first conductive trace 303 is a power plane, then both second conductive traces are ground planes. Conversely, if the first conductive trace 303 is a ground plane, then both second conductive traces are power planes. The second conductive traces 310A and 310B are not directly connected to the actuators 15; however, they are connected to corresponding reference planes (power or ground planes) in the CMOS drive circuit layer via a plurality of conductor posts 307.

It will be appreciated that the second conductive trace 310 can be formed during MEMS fabrication in a manner that is substantially similar to the first conductive trace 303 described above. Accordingly, the second conductive trace 310 is typically constructed of a thermoelastic beam material and may be a multilayer structure to enhance electrical conductivity.

The first and second conductive traces 303 and 310 function primarily to reduce the series resistance value of the corresponding reference plane in the CMOS drive circuit layer. Thus, by providing conductive traces in the MEMS layer connected in parallel with corresponding reference planes in the CMOS layer, the overall resistance values of these reference planes can be significantly reduced by the simple application of Ohm's law. Typically, the conductive traces are constructed to minimize their resistance values, for example, by maximizing their width or depth as much as possible.

The series resistance value of a ground plane or power plane can be reduced by at least 25%, at least 50%, at least 75%, or at least 90% due to the relationship of conductive traces in the MEMS layer. Likewise, the self-inductance of a ground plane or power plane can be similarly fabricated. The significant reduction in series resistance and self-inductance of both the ground plane and the power plane helps to minimize the ground bounce of the column head IC 300, thereby improving the efficiency of the print head. The inventor of the present invention has learned that in the print head IC 300 shown in Fig. 31, the mutual inductance between the power plane and the ground plane is also reduced, although the quantitative analysis of the mutual inductance requires a complicated model, but this is beyond the scope of the present case.

Figures 32 and 33 provide simplified CMOS drive circuit diagrams for pFET and nFET drive transistors. The drive transistor (nFET or pFET) is directly connected to the second terminal of each actuator 15 via the actuator post 8 as shown in FIG.

In Figure 32, actuator 15 is connected between the drain of the pFET and the ground plane ("Vss"). A power plane ("Vpos") is connected to the source of the pFET, and the gate accepts the logic transmit signal. When the pFET receives a low voltage at the gate (due to the NAND gate), current flows through the pFET causing the actuator 15 to be actuated. In the pFET circuit, a first terminal of the actuator is coupled to a ground plane provided by the first conductive trace 303, while a second terminal of the actuator is coupled to the pFET. Thus, the second conductive traces provide a power plane.

In Figure 33, actuator 15 is coupled between the power plane ("Vpos") and the source of an nFET. When the nFET (due to the AND gate) accepts a high voltage, current flows through the nFET causing the actuator 15 to be actuated. In the nFET circuit, a first terminal of the actuator is coupled to a power plane provided by the first conductive trace 303, while a second terminal of the actuator is coupled to the nFET. Thus, the second conductive traces provide a ground plane.

As can be appreciated from Figures 32 and 33, the first and second conductive traces 303 and 310 can be compatible with a pFET or nFET.

Of course, the benefits of using conductive traces as described above are not limited to the nozzle 210 shown in FIG. A printhead IC having any type of actuator can in principle benefit from the conductive traces described above.

Figure 34 shows a printhead IC 400 comprising a plurality of nozzles 100 (similar to the nozzle type described with reference to Figure 16) configured as longitudinally extending nozzle train pairs 302A and 302B. The first conductive trace 303 extends between the pair of nozzle columns 302A and 302B, and the second conductive traces 310A and 310B are located at the flank of the pair of nozzle rows. Each of the actuators 15 of one of the other nozzles 100 has a first terminal connected to the first conductive trace 303 via a lateral connector 305, and a second terminal connected to the underlying FET via the actuator post 8. . Thus, it will be appreciated that the printhead IC 400, such as the printhead IC, is provided in the sense that the conductive traces 303 and 310 provide a common reference plane by being connected to a corresponding reference plane in the underlying CMOS driver circuit. 300 operations. Again, the first conductive trace 303 is directly connected to one terminal of each actuator to provide a common reference plane for each of the two nozzle rows 302A and 302B.

It will be appreciated by those skilled in the art that various changes and/or modifications may be made to the embodiments of the inventions disclosed in the particular embodiments without departing from the spirit and scope of the invention. Therefore, the present embodiments are to be considered in all respects

1. . . Substrate

4. . . wall

5. . . Nozzle chamber

6. . . Polyimine

7. . . Top wall

8. . . Actuator column

2. . . electrode

9. . . Metal pad

16. . . Passive beam (piece)

10. . . Active beam

11. . . Partial nozzle opening

12. . . Beam

13. . . Nozzle opening

14. . . Movable paddle

15. . . Actuator

17. . . gap

18. . . Immobile part

19. . . Polymer layer

twenty one. . . Inkjet surface

20. . . Ink supply pipe

100. . . Nozzle assembly

14A. . . Top wall paddle

14B. . . Top wall paddle

200. . . Inkjet nozzle assembly

15A. . . Thermal bending actuator

15B. . . Thermal bending actuator

210. . . Nozzle assembly

220. . . nozzle

222. . . Oval area

230. . . Page width print head

231. . . nozzle

235. . . Print media

236. . . arrow

232. . . Point position

234. . . Point position

d. . . Point pitch

n. . . Nozzle pitch

240. . . Page width print head

242. . . Waste nozzle

243. . . Functional nozzle

244. . . Functional nozzle

236. . . Longitudinal axis

247. . . Main point location

248. . . Main point location

250. . . Page width print head

251A-E. . . Print head IC

257. . . Junction area

255. . . nozzle

258. . . edge

259. . . Dead space

253. . . Shifted nozzle triangle

75. . . Adhesive pad

76. . . Alignment reference point

260. . . Print head IC

264. . . nozzle

262. . . nozzle

266. . . nozzle

270. . . Print head IC

272. . . nozzle

274. . . Main point location

276. . . Secondary point position

271. . . nozzle

300. . . Print head IC

302A. . . Nozzle column

302B. . . Nozzle column

303. . . First conductive trace

304. . . Nozzle plate

305. . . Transverse connector

307. . . Conductor column

310A. . . Second conductive trace

310B. . . Second conductive trace

400. . . Print head IC

14C. . . Movable paddle

14D. . . Movable paddle

221. . . Damping column

Selected embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which

Figure 1 is a side cross-sectional view of the inkjet nozzle assembly partially fabricated after the first sequence of steps, wherein the nozzle chamber sidewalls are formed;

Figure 2 is a perspective view of the partially fabricated ink jet nozzle assembly shown in Figure 1;

Figure 3 is a side cross-sectional view of the inkjet nozzle assembly partially fabricated after the second sequence of steps, wherein the nozzle chamber sidewall is filled with polyimide;

Figure 4 is a perspective view of the partially fabricated ink jet nozzle assembly shown in Figure 3;

Figure 5 is a side cross-sectional view of the inkjet nozzle assembly partially fabricated after the third sequence of steps, wherein the connector posts are formed to the bottom wall of the chamber;

Figure 6 is a perspective view of the partially fabricated ink jet nozzle assembly shown in Figure 5;

Figure 7 is a side cross-sectional view of the ink jet nozzle assembly partially manufactured after the fourth step sequence, wherein the conductive metal sheets are formed;

Figure 8 is a perspective view of the partially fabricated ink jet nozzle assembly shown in Figure 7;

Figure 9 is a side cross-sectional view of the ink jet nozzle assembly partially fabricated after the fifth sequence of steps, wherein the active beam member of the thermal bending actuator is formed;

Figure 10 is a perspective view of the partially fabricated ink jet nozzle assembly shown in Figure 9;

Figure 11 is a side cross-sectional view of the ink jet nozzle assembly partially fabricated after the sixth sequence of steps, wherein the top wall portion including the activity of the thermal bending actuator is formed;

Figure 12 is a perspective view of the partially fabricated ink jet nozzle assembly shown in Figure 11;

Figure 13 is a side cross-sectional view of the ink jet nozzle assembly partially fabricated after the seventh step sequence, wherein the hydrophobic polymer layer is deposited and photopatterned;

Figure 14 is a perspective view of the partially fabricated ink jet nozzle assembly shown in Figure 13;

Figure 15 is a side cross-sectional view of a fully fabricated ink jet nozzle assembly;

Figure 16 is an open perspective view of the ink jet nozzle assembly shown in Figure 15;

Figure 17 is a plan view of an ink jet nozzle having opposed movable movable top wall blades and a movable nozzle opening;

Figure 18 is a plan view of an ink jet nozzle having movable top wall blades that are movable relative to a stationary nozzle opening;

Figure 19 is a simplified circuit diagram of two actuators for independently controlling the ink jet nozzle shown in Figure 17;

Figure 20 is a plan view of a portion of a printhead including an ink jet nozzle having four movable top wall blades;

Figure 21 shows a two-dimensional printable area for the ink jet nozzle shown in Figure 20;

Figure 22 is a side elevational view of a portion of an ink jet printhead constructed to provide a print dot density greater than the nozzle density of the printhead;

Figure 23 is a side elevational view of a portion of an ink jet printhead constructed to compensate for waste nozzles;

Figure 24 is a plan view of an ink jet printhead including five docked printhead ICs;

Figure 25 is a plan view of another print head IC;

Figure 26 is a perspective view of the end portion of the print head IC shown in Figure 25;

Figure 27 is a perspective view of a joint region between a pair of print head ICs shown in Figure 25;

Figure 28 is a perspective view of a joint area of a pair of print head ICs, including nozzles constructed to be printed into the joint area;

Figure 29 is a side view of a row of print head ICs, wherein a printable area is longer than a corresponding nozzle array;

Figure 30 is a side elevational view of a row of printhead ICs, wherein the end nozzles are constructed to be printed into respective joint regions;

Figure 31 is a plan view of a print head IC having conductive traces disposed on a nozzle plate;

32 is a simplified circuit diagram of an actuator for connection to a driving pFET;

Figure 33 is a simplified circuit diagram of an actuator for connection to a driving nFET;

Figure 34 is a plan view of another printhead IC having conductive traces disposed on a nozzle plate.

7. . . Top wall

8. . . Actuator column

10. . . Active beam

13. . . Nozzle opening

15. . . Actuator

17. . . gap

20. . . Ink supply pipe

200. . . Inkjet nozzle assembly

300. . . Print head IC

302A. . . Nozzle column

302B. . . Nozzle column

303. . . First conductive trace

304. . . Nozzle plate

305. . . Transverse connector

307. . . Conductor column

310A. . . Second conductive trace

310B. . . Second conductive trace

Claims (20)

An inkjet printhead comprising: a substrate comprising a drive circuit layer; a plurality of nozzle assemblies disposed on an upper surface of the substrate and configured to print one or more along the print a nozzle row extending longitudinally of the head, each nozzle assembly comprising: a nozzle chamber having a bottom wall defined by the upper surface, a top wall spaced apart from the bottom wall, and an actuator for ink Ejecting from a nozzle opening defined in the top wall; a nozzle plate extending across the printhead, the nozzle plate at least partially defining the top wall; and at least one conductive trace disposed on the nozzle plate Extending the conductive traces along the printhead and parallel to the nozzle rows, wherein the conductive traces are connected via a plurality of conductor posts extending between the drive circuit layer and the conductive traces To a common reference plane in the driver circuit layer. The inkjet printhead of claim 1, wherein the common reference plane defines a ground plane or a power plane. An inkjet printhead according to claim 1, comprising at least one first conductive trace, wherein the first conductive trace is directly connected to at least one nozzle row adjacent to the first conductive trace Multiple actuators. The inkjet printhead of claim 3, further comprising at least one second conductive trace, wherein the second conductive trace is not directly connected to any actuator. The inkjet printhead of claim 3, wherein the first conductive trace extends continuously along the printhead to provide a nozzle for the nozzle A common reference plane for each actuator in the column. The inkjet printhead of claim 3, wherein the first conductive trace extends discontinuously along the printhead to provide a common for a set of actuators in the nozzle array Reference plane. An inkjet printhead according to claim 3, wherein the first conductive trace is disposed between respective nozzle row pairs, the first conductive traces being provided in two nozzle rows for the pair of nozzle columns The common reference plane of the plurality of actuators. An inkjet printhead according to claim 3, wherein each of the actuators has a first terminal directly connected to the first conductive trace and a second terminal connected to a driving transistor in the driving circuit layer. . An inkjet printhead according to claim 8 wherein each top wall comprises at least an actuator and the first terminal of each actuator extends transversely across the nozzle relative to the first conductive trace A lateral connector of the board is connected to the first conductive trace. The ink jet print head of claim 9, wherein the second terminal is connected to the drive transistor via an actuator post extending between the drive circuit layer and the second terminal. The inkjet printhead of claim 10, wherein the actuator columns are perpendicular to a plane of the first conductive trace. An ink jet print head according to claim 9 wherein each of the top walls comprises at least one movable paddle comprising a respective thermal bending actuator, the paddles being oriented toward the bottom of the respective nozzle chamber Wall motion to cause ink to exit from the nozzle opening, wherein the thermal bending actuator comprises: An upper thermoelastic active beam member having the first and second terminals; and a lower passive beam welded to the thermoelastic active beam member such that the thermoelastic active when current passes through the thermoelastic active beam member The beam members expand relative to the passive beam causing the respective paddles to flex toward the bottom wall of the nozzle chamber. The inkjet printhead of claim 12, wherein the thermoelastic active beam member is coplanar with the conductive trace. The inkjet printhead of claim 12, wherein the thermoelastic active beam member comprises the same material as the conductive trace. An ink jet print head according to claim 1, wherein the nozzle plate comprises a ceramic material. An ink jet print head according to claim 4, wherein the drive circuit layer comprises a drive field effect transistor (FET) for each actuator, each drive FET comprising a signal for receiving a logic transmit signal a gate, a source in electrical communication with the power plane, and a drain in electrical communication with the ground plane, the drive FET being one of: a pFET, wherein the actuator is coupled to the drain Between the ground planes; or an nFET, wherein the actuator is coupled between the power plane and the source. An inkjet printhead of claim 16 wherein the drive FET is a pFET and the first conductive trace provides the ground plane, and wherein the first terminal of the actuator is coupled to the first conductive trace A wire and a second terminal of the actuator are coupled to the drain of the pFET. The inkjet printhead of claim 17, wherein the second conductive trace provides the power plane and is connected to a source of the pFET. An inkjet printhead of claim 16 wherein the drive FET is an nFET and the first conductive trace provides the power plane, and wherein the first terminal of the actuator is coupled to the first trace A line and a second terminal of the actuator are coupled to a source of the nFET. The inkjet printhead of claim 19, wherein the second conductive trace provides the ground plane and is connected to the drain of the nFET.