Hewlett-packard Development Company, L.p.

David Maxfield

Andrew L Van Brocklin

Eric T Martin

Alexander N Govyadinov

Adam L Ghozeil

Scott A Linn

Peter James Fricke

Sterling Chaffins

Dustin W Blair

Sean P McClelland

Gerard Alzona

James Michael Gardner

Mark H MacKenzie

Vincent C Korthuis

Christie Dudenhoefer

Kenneth Ward

Andrew F Phillips

Eugene J Mar

Andrew Queisser

Matthew P Heineck

Andrew L Van Brooklin

Mark H Mackenzie

Measuring an inkjet nozzle may include taking at least one impedance measurement after the firing command is sent to detect the presence of a drive bubble and taking another impedance measurement to detect a collapse of the drive bubble.

Detecting a drive bubble formation and collapse

In some examples, a control circuit for a bypass capacitor includes a switch assembly that is activatable between a first state to connect the bypass capacitor between nodes, and a second state to disconnect the bypass capacitor between the nodes. The switch assembly includes a first switch to activate a first path comprising a first resistance to begin charging the bypass capacitor, and a second switch to, a delayed time after the activating of the first path, activate a second path comprising a second resistance lower than the first resistance, the activated second path connecting the bypass capacitor between the nodes.

Switches for bypass capacitors

In some examples, a controller receives impedance sensor values from an impedance sensor in a printhead, determines whether the impedance sensor values correlate to a production of an effective drive bubble for the printhead, and issues a command to modify a firing parameter for a fluid ejector of the printhead based on the impedance sensor values.

Modifying firing parameters for printheads

A liquid propelling component includes a liquid channel, a circuit block. The circuit block includes a first conductor disposed in the liquid channel to be in contact with liquid in the channel and a second conductor insulated from liquid in the channel. The liquid propelling component further includes a memory storing a digital code that corresponds to an analog value of the second conductor under a predefined charge.

Liquid propelling component

In an implementation, a printhead includes a nozzle and a fluid channel. A sensor plate is located within the fluid channel. An impedance measurement circuit is coupled to the sensor plate to measure impedance of fluid within the channel during a fluid movement event that moves fluid past the sensor plate.

Printheads with sensor plate impedance measurement

In some examples, a printhead includes a firing chamber to receive printer fluid, an ejector positioned in the firing chamber to eject printer fluid droplets from the printhead, and a nozzle in fluid communication with the firing chamber. The printhead can further include an impedance sensor positioned in the firing chamber to contact printer fluid to measure impedance values of the printer fluid. The impedance sensor can be connectable to a controller to transmit impedance values of printer fluid to the controller.

Printer fluid impedance sensing in a printhead

An example provides a fluid ejection apparatus including a fluid feed slot along a length of a print head die of the fluid ejection apparatus to supply a fluid to a plurality of drop ejectors, control circuitry adjacent to at least one side of the fluid feed slot to control ejection of drops of fluid from the plurality of drop ejectors, and a single power supply connector at an end of the print head die to supply power to the control circuitry.

Fluid ejection apparatus with single power supply connector

A printhead assembly is provided, the printhead assembly including a printhead die, a black fluid slot formed in the printhead die to deliver black printing fluid, and a color fluid slot formed in the printhead die to deliver color printing fluid.

Printhead assembly

An example provides a fluid ejection apparatus including a fluid feed slot to supply a fluid to a plurality of drop ejectors, a first rib at a first side of the fluid feed slot and supporting drop ejection circuitry to control ejection of drops of the fluid from the plurality of drop ejectors, and a second rib at a second side, opposite the first side, of the fluid feed slot supporting a thermal sensor to facilitate determination of a temperature of the first rib and the second rib.

Fluid ejection apparatus with single-side thermal sensor

A method for determining an issue in an inkjet nozzle with impedance measurements, includes taking a first impedance measurement to detect a drive bubble with an impedance sensor; and taking a second impedance measurement to detect said drive bubble with said impedance sensor after said first impedance measurement.

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Philomath, OR, United States of America

David Maxfield