Abstract: A liquid discharge head includes a discharge port through which a liquid is discharged, an element for discharging the liquid from the discharge port, a channel through which the liquid is supplied to the discharge port, and a film member that is provided so as to be in contact with the liquid in a liquid chamber in the channel. The film member has a corrugated structure in which a plurality of loop-shaped projecting portions and a plurality of loop-shaped recessed portions are alternately formed. When seen in a direction perpendicular to a plane of the film member, the corrugated structure has a loop shape having a linear portion.

Abstract: A liquid jetting device is arranged to eject a droplet of a liquid. The device includes a nozzle, a liquid duct connected to the nozzle, an electro-mechanical transducer arranged to create an acoustic pressure wave in the liquid in the duct, and an electronic control system arranged to apply to the transducer a voltage signal having a waveform configured for ejecting a droplet from the nozzle. The waveform is further configured to quench a residual acoustic pressure wave in the liquid duct and includes a jet pulse, a subsequent first quench pulse having a polarity opposite to that of the jet pulse, and a subsequent second quench pulse having the same polarity as the jet pulse.

Abstract: An inkjet print head includes a plurality of droplet jetting devices. The plurality of droplet jetting devices is formed of a nozzle layer defining, for each of the plurality of droplet jetting devices, a nozzle, a membrane layer carrying, on a membrane, a restrictor layer and an actuator for generating pressure waves in a liquid in a pressure chamber that is connected to the nozzle. The actuator is positioned in an actuator chamber in the restrictor layer, and a distribution layer defining a supply line for supplying the liquid to the pressure chamber. The restrictor layer includes an inlet restrictor having a cross-section and an outlet restrictor positioned on opposites sides of the actuator and having a cross-section that is different from the cross-section of the inlet restrictor.

Abstract: A liquid jetting device is arranged to eject a droplet of a liquid. The device includes a nozzle, a liquid duct connected to the nozzle, an electro-mechanical transducer arranged to create an acoustic pressure wave in the liquid in the duct, and an electronic control system arranged to apply to the transducer a voltage signal having a waveform configured for ejecting a droplet from the nozzle. The waveform is further configured to quench a residual acoustic pressure wave in the liquid duct and includes a jet pulse, a subsequent first quench pulse having a polarity opposite to that of the jet pulse, and a subsequent second quench pulse having the same polarity as the jet pulse.

Abstract: A liquid ejection device includes a liquid duct system having a plurality of nozzles, a plurality of pressure chambers communicating with the nozzles, and a liquid supply line communicating with the pressure chambers; a plurality of actuators arranged to pressurize the liquid in the pressure chambers for ejecting droplets of liquid through the nozzles; and a dampening device including a cavity that is in fluid communication with the duct system and is delimited by a resilient foil for dampening pressure waves in the liquid. The resilient foil is pre-formed in a corrugated shape.

Abstract: A process of manufacturing droplet jetting devices includes bonding together a nozzle wafer defining nozzles of the jetting devices, a membrane wafer carrying, on a membrane, actuators for generating pressure waves in a liquid in pressure chambers that are connected to the nozzles, and a distribution wafer forming a distribution layer that defines supply lines for supplying the liquid to the pressure chambers from a liquid reservoir formed on a side of the distribution layer opposite to the membrane wafer; and dicing the bonded wafers. The distribution layer has a thickness larger than the thickness of each of the other two wafers. A restrictor for controlling the inertance of the liquid supply line is formed through the distribution layer in a direction normal to the plane of that layer.

Abstract: An inkjet print head comprises a fluid channel, the fluid channel including a pressure chamber; a piezo actuator including an active piezo stack and a membrane, the active piezo stack being provided at a surface of the membrane and the membrane forming a flexible wall of the pressure chamber, and a cavity having a cavity dimension determining a wall dimension of the membrane. The method of manufacturing such a print head includes selecting a desired actuator compliance; manufacturing a first print head layer including the piezo actuator; determining at least one actual actuator property of the piezo-actuator; determining a desired wall dimension based on the actual actuator property such that the combination of the piezo actuator and the membrane having the desired wall dimension provides for the desired actuator compliance; and manufacturing a second print head layer including the cavity.

Abstract: A process of manufacturing droplet jetting devices includes bonding together a nozzle wafer defining nozzles of the jetting devices, a membrane wafer carrying, on a membrane, actuators for generating pressure waves in a liquid in pressure chambers that are connected to the nozzles, and a distribution wafer forming a distribution layer that defines supply lines for supplying the liquid to the pressure chambers from a liquid reservoir formed on a side of the distribution layer opposite to the membrane wafer; and dicing the bonded wafers. The distribution layer has a thickness larger than the thickness of each of the other two wafers. A restrictor for controlling the inertance of the liquid supply line is formed through the distribution layer in a direction normal to the plane of that layer.

Abstract: A MEMS chip having at least two chip components bonded together by means of an adhesive layer that is applied to at least one of two mating bonding surfaces of the two components, wherein a pattern of finely distributed micro-cavities is formed in at least one of the two mating bonding surfaces, said micro-cavities being arranged to accommodate a major part of the adhesive.

Abstract: An inkjet print head comprises a fluid channel for holding a channel amount of fluid, the fluid channel comprising a pressure chamber in fluid communication with a nozzle orifice; a piezo actuator comprising an active piezo stack, comprising a first electrode, a second electrode, and a piezo-material layer arranged between the first and the second electrode; and a membrane, the active piezo stack being provided at a surface of the membrane and the membrane forming a flexible wall of the pressure chamber, and a cavity having a cavity dimension determining a wall dimension of the membrane. The piezo-actuator is arranged to deform by bending upon application of a voltage over the first electrode and the second electrode, and the piezo actuator has an actuator compliance.

Abstract: In a print head having a bimorph thin-film piezo actuator, the piezo-electric actuator is arranged on a membrane at a first side of the piezo-electric actuator and a passive layer is arranged on the piezo-electric actuator at a second side of the piezo-electric actuator, wherein the second side is opposite to the first side. The membrane is more compliant, at least in a lateral direction, for contraction than the passive layer. Thus, a bending direction of the actuator is affected. As a consequence, there is no need for a bias voltage on the actuator during a standby state of the print head. Omitting the bias voltage during standby results in an increased lifetime and stability of the actuator assembly.

Abstract: In a print head having a bimorph thin-film piezo actuator, the piezo-electric actuator is arranged on a membrane at a first side of the piezo-electric actuator and a passive layer is arranged on the piezo-electric actuator at a second side of the piezo-electric actuator, wherein the second side is opposite to the first side. The membrane is more compliant, at least in a lateral direction, for contraction than the passive layer. Thus, a bending direction of the actuator is affected. As a consequence, there is no need for a bias voltage on the actuator during a standby state of the print head. Omitting the bias voltage during standby results in an increased lifetime and stability of the actuator assembly.

Abstract: A MEMS chip having at least two chip components bonded together by means of an adhesive layer that is applied to at least one of two mating bonding surfaces of the two components, wherein a pattern of finely distributed micro-cavities is formed in at least one of the two mating bonding surfaces, said micro-cavities being arranged to accommodate a major part of the adhesive.

Abstract: An inkjet print head for expelling a droplet of a fluid through a nozzle orifice comprises a fluid channel for holding a channel amount of fluid, the fluid channel comprising a pressure chamber in fluid communication with the nozzle orifice and a piezo actuator. The piezo actuator comprises an active piezo stack, which stack comprises a first electrode, a second electrode, and a piezo-material layer arranged between the first and the second electrode, and the piezo actuator comprises a membrane having a first side and a second side, the second side being opposite to the first side. The active piezo stack is provided at the first side and the pressure chamber at the second side such that the membrane forms a flexible wall of the pressure chamber. The fluid channel, when holding the channel amount of fluid, has a fluid compliance and the piezo actuator has an actuator compliance.

Abstract: A method of controlling a pressure of a fluid in a pressure chamber, which pressure chamber is delimited by an actuator membrane having a first piezoelectric portion arranged in a central zone of the actuator membrane and at least one second piezoelectric portion arranged in at least one peripheral zone of the actuator membrane; and an ink jet printing device. In a neutral stage, a first flexure state of the actuator membrane is provided by applying first and second voltages to respective piezoelectric portions. In an activation stage, the first and second voltages are temporarily varied, without reversing their polarity, such that a curvature of the central part of the actuator membrane and a curvature of the peripheral part of the actuator membrane are changed in opposite directions, in order to expell a droplet of fluid through a nozzle.

Abstract: A droplet generating device includes a wafer with a recess that defines a pressure chamber, a flexible membrane bonded to the wafer so as to cover the recess and form a wall of the pressure chamber, and an actuator attached to the membrane for flexing the membrane to generate a pressure wave in a liquid in the pressure chamber, the pressure chamber having a first port connected to a liquid supply line, and a second port connecting the pressure chamber to a nozzle, at least one of the ports being arranged adjacent to the membrane, wherein the wafer forms at least one island portion that projects into the at least one of the ports, engages the membrane and divides the port into at least two separate passages, and wherein the at least one island portion is arranged to delimit a flexing part of the membrane on a side of the at least one of the ports.

Abstract: A droplet ejection device includes a pressure chamber; a nozzle orifice arranged in fluid connection with the pressure chamber; an actuator system for generating a pressure wave in a liquid present in the pressure chamber; and an obstruction member arranged in the pressure chamber in a position opposite to the nozzle orifice. The obstruction member comprises a first surface facing the nozzle orifice and rigidly coupled to a wall of the pressure chamber via a support. The support is arranged near the first surface of the obstruction member. The droplet ejection device according to the present invention may further comprise a structured nozzle inflow means which provides a gradual transition from the hollow shaped liquid passage to the nozzle orifice. The droplet ejection device prevents or at least mitigates air entrapment in dead volumes present in the interior of the droplet ejection device.

Abstract: A droplet ejection device comprising a flow passage, a nozzle orifice formed in a wall of the flow passage, a circulation system for circulating a liquid through the flow passage, and an actuator system for generating a pressure wave in the liquid in the flow passage, wherein an obstruction member is arranged in the flow passage in a position opposite to the nozzle orifice and projecting towards the nozzle orifice.

Abstract: A droplet ejection device includes a pressure chamber; a nozzle orifice arranged in fluid connection with the pressure chamber; an actuator system for generating a pressure wave in a liquid present in the pressure chamber; and an obstruction member arranged in the pressure chamber in a position opposite to the nozzle orifice. The obstruction member comprises a first surface facing the nozzle orifice and rigidly coupled to a wall of the pressure chamber via a support. The support is arranged near the first surface of the obstruction member. The droplet ejection device according to the present invention may further comprise a structured nozzle inflow means which provides a gradual transition from the hollow shaped liquid passage to the nozzle orifice. The droplet ejection device prevents or at least mitigates air entrapment in dead volumes present in the interior of the droplet ejection device.

Abstract: A print head comprises a pressure chamber in fluid communication with a nozzle and an actuator structure in operative communication with the pressure chamber for generating a pressure wave in the pressure chamber. The actuator structure comprises a membrane, wherein a first surface of the membrane forms a flexible wall of the pressure chamber and a piezo actuator, wherein the piezo actuator is arranged on a second surface of the membrane, the second surface being opposite of the first surface, such that the membrane is deformed at the position of the piezo actuator upon actuation of the piezo actuator. In the print head, the membrane is pivotably clamped between a first structure layer and a second structure layer such that the membrane pivots at the location of clamping upon deformation of the membrane due to actuation of the piezo actuator.