Abstract: A technique includes coupling outlets of a first ink supply and a second ink supply together to provide ink to a printhead of a printer; and pressurizing the first ink supply and the second ink supply with air so that an air pressure of the first ink supply has a different air pressure than an air pressure of the second ink supply. The technique includes monitoring an ink-to-air differential pressure of the first ink supply or the second ink supply; and detecting an ink state for the printer based on the monitored ink-to-air differential pressure.

Abstract: A technique includes coupling outlets of a first ink supply and a second ink supply together to provide ink to a printhead of a printer; and pressurizing the first ink supply and the second ink supply with air so that an air pressure of the first ink supply has a different air pressure than an air pressure of the second ink supply. The technique includes monitoring an ink-to-air differential pressure of the first ink supply or the second ink supply; and detecting an ink state for the printer based on the monitored ink-to-air differential pressure.

Abstract: A fluid injection module may include a fluid ejection die, a die carrier, a bypass fluid passage in at least one pressure regulator. The fluid ejection die may include nozzle orifices on a front face of the die, first and second fluid passages extending through the die and a microchannel extending from the first fluid passage to the second fluid passage proximate the nozzle orifices to circulate fluid from the first fluid passage to the second fluid passage. Third and fourth fluid passages may extend through the die carrier. The bypass fluid passage may extend from the third fluid passage to the fourth fluid passage while being connected to the first fluid passage and the second fluid passage. The at least one pressure regulator is to induce pressure differential driven fluid flow across the microchannel and across the bypass fluid passage.

Abstract: A print module may include a printhead die. The printhead die may include a chamber layer having ink chambers and micro-channels formed in the chamber layer. The print module may further include a die carrier including manifold passages through which ink flows to and from the printhead die and dual pressure regulators to flow fluid through the micro-channels of the printhead die.

Abstract: A fluid injection module may include a fluid ejection die, a die carrier, a bypass fluid passage in at least one pressure regulator. The fluid ejection die may include nozzle orifices on a front face of the die, first and second fluid passages extending through the die and a microchannel extending from the first fluid passage to the second fluid passage proximate the nozzle orifices to circulate fluid from the first fluid passage to the second fluid passage. Third and fourth fluid passages may extend through the die carrier. The bypass fluid passage may extend from the third fluid passage to the fourth fluid passage while being connected to the first fluid passage and the second fluid passage. The at least one pressure regulator is to induce pressure differential driven fluid flow across the microchannel and across the bypass fluid passage.

Abstract: A print module includes a printhead die, an input regulator to regulate input fluid pressure to the die, and an output regulator to regulate output fluid pressure from the die. A method includes receiving fluid at an input regulator to a print module, creating a fluid pressure differential within the print module between the input regulator and an output regulator, flowing fluid from the input regulator through a printhead die and to an output regulator using the pressure differential, and drawing fluid from the output regulator.

Abstract: A print module may include a printhead die. The printhead die may include a chamber layer having ink chambers and micro-channels formed in the chamber layer. The print module may further include a die carrier including manifold passages through which ink flows to and from the printhead die and dual pressure regulators to flow fluid through the micro-channels of the printhead die.

Abstract: In one example, a processor readable medium has instructions thereon that when executed cause a printer to: introduce an unsaturated printing fluid into a channel through which fluid may pass to a printhead; dispense unsaturated printing fluid with the printhead to remove air from the channel; and then introduce regular printing fluid into the channel; and dispense printing fluid with the printhead until regular printing fluid is dispensed from the printhead.

Abstract: A print module includes a printhead die, an input regulator to regulate input fluid pressure to the die, and an output regulator to regulate output fluid pressure from the die. A method includes receiving fluid at an input regulator to a print module, creating a fluid pressure differential within the print module between the input regulator and an output regulator, flowing fluid from the input regulator through a printhead die and to an output regulator using the pressure differential, and drawing fluid from the output regulator.

Abstract: A print module includes a printhead die, an input regulator to regulate input fluid pressure to the die, and an output regulator to regulate output fluid pressure from the die. A method includes receiving fluid at an input regulator to a print module, creating a fluid pressure differential within the print module between the input regulator and an output regulator, flowing fluid from the input regulator through a printhead die and to an output regulator using the pressure differential, and drawing fluid from the output regulator.

Abstract: In one example, a processor readable medium has instructions thereon that when executed cause a printer to: introduce an unsaturated printing fluid into a channel through which fluid may pass to a printhead; dispense unsaturated printing fluid with the printhead to remove air from the channel; and then introduce regular printing fluid into the channel; and dispense printing fluid with the printhead until regular printing fluid is dispensed from the printhead.

Abstract: Mounting apparatus includes a shaft member having a surface including a base portion and a sidewall portion forming an intersecting angle therebetween. The mounting apparatus also includes a compression member disposed across from the sidewall portion of the shaft member.

Abstract: Mounting apparatus includes a shaft member having a shaft fluidic channel therein and a shaft exterior surface. The shaft exterior surface includes a base portion and a sidewall portion forming an intersecting angle therebetween. The mounting apparatus also includes a compression member disposed across from the sidewall portion of the shaft member.

Abstract: In one example, a fluid flow structure includes a flow path configured to simultaneously move a liquid up a slope and move a bubble down the slope. In one example, a fluid flow structure includes a horizontal conduit, a reservoir to hold a liquid above the conduit, an inlet into which liquid from the reservoir may enter the conduit, an outlet through which liquid may leave the conduit, and multiple capillary channels in the conduit extending continuously from the inlet to the outlet.

Abstract: A fluid dispensing apparatus including a fluid ejector including a fluid reservoir having fluid, and configured to eject the fluid, a vacuum pump configured to create negative pressure in an activation mode and to create approximately no pressure in a deactivation mode, a meniscus pressure regulator configured to regulate the negative pressure received from the vacuum pump, a leaking member configured to reduce the negative pressure received from the vacuum pump towards or equal to atmospheric pressure in response to the vacuum pump being placed in the deactivation mode, and a back pressure regulator having a pressure reference port to receive the reduced negative pressure from the leaking member and the regulated negative pressure from the meniscus pressure regulator, the back pressure regulator configured to maintain a non-retraction negative pressure value to position a fluid meniscus in a non-retracted state and a retraction negative pressure value to position the fluid meniscus in a retracted state.

Abstract: A print module includes a printhead die, an input regulator to regulate input fluid pressure to the die, and an output regulator to regulate output fluid pressure from the die. A method includes receiving fluid at an input regulator to a print module, creating a fluid pressure differential within the print module between the input regulator and an output regulator, flowing fluid from the input regulator through a printhead die and to an output regulator using the pressure differential, and drawing fluid from the output regulator.

Abstract: Mounting apparatus includes a shaft member having a shaft fluidic channel therein and a shaft exterior surface. The shaft exterior surface includes a base portion and a sidewall portion forming an intersecting angle therebetween. The mounting apparatus also includes a compression member disposed across from the sidewall portion of the shaft member.

Abstract: In one embodiment, a drop detector includes a light source for illuminating drops passing through a drop zone and a light detector near the light source for detecting light scattered off the drops back toward the light source. In another embodiment, a drop detector includes a light source operable to emit a beam of light for illuminating drops passing through a drop zone and a light detector positioned near the light source to detect substantially only light scattered off the drops at a scatter angle ? in the range of 177° to 180°, where ? represents a direction of scattered light measured with respect to an axis of the light beam with ?=0° lying along the axis in a direction of travel of the light beam and ?=180° lying along the axis opposite the direction of travel of the light beam.

Abstract: A fluid dispensing apparatus including a fluid ejector including a fluid reservoir having fluid, and configured to eject the fluid, a vacuum pump configured to create negative pressure in an activation mode and to create approximately no pressure in a deactivation mode, a meniscus pressure regulator configured to regulate the negative pressure received from the vacuum pump, a leaking member configured to reduce the negative pressure received from the vacuum pump towards or equal to atmospheric pressure in response to the vacuum pump being placed in the deactivation mode, and a back pressure regulator having a pressure reference port to receive the reduced negative pressure from the leaking member and the regulated negative pressure from the meniscus pressure regulator, the back pressure regulator configured to maintain a non-retraction negative pressure value to position a fluid meniscus in a non-retracted state and a retraction negative pressure value to position the fluid meniscus in a retracted state.

Abstract: Systems, methods, and other embodiments associated with fluid-jet dispensers are described. In one embodiment, a method (400) controls a fluid jet dispenser. The fluid jet dispenser includes a plurality of nozzles for precisely ejecting fluid and a plurality of ejection chambers. The fluid-jet dispenser includes one or more fluid channels for supplying fluid from a fluid reservoir to the plurality of ejection chambers and corresponding nozzles. The method includes detecting (405) that the fluid-jet dispenser has not ejected fluid for a predetermined time. The method applies a de-prime pressure (410). The de-prime pressure is a negative pressure to withdraw fluid from the nozzles and the ejection chambers to a high capillary force area within each of the one or more fluid channels to remove fluid from the plurality of nozzles.