Hewlett-packard Development Company, L.p.

Joan-Albert Miravet Jimenez

Albert Crespi Serrano

Francesc Ros Cerro

David Butinya

Marta Coma Vives

Alex Andrea Tallada

Francisco Lopez Moral

Marina Ferran Farres

Dorkaitz Alain Vazquez Fernandez

Carlos Chover Lopez

Alvin Zheng-Hui Yu

A printing fluid delivery system comprising a fluid pump having an inlet and an outlet, a valve connected to the outlet of the fluid pump, and a controller to close the valve while the fluid pump is driven to increase the pressure at the outlet of the fluid pump based on a service condition and to open the valve based on a predefined relief condition to relieve the pressure at the outlet of the fluid pump.

Fluid delivery system with pump servicing features

A differential pressure sensor is used for measuring or identifying a pressure difference, for example to determine a movement or speed of fluid in a fluid conduit or printer re-circulation conduit. The differential pressure sensor determines the difference between an air pressure and a fluid pressure, wherein the fluid is moving in a flow channel. The flow channel includes a surface conveying a fluid between a first port and second port. An opening in the surface of the flow channel provides a fluid communication between the differential pressure sensor and fluid. Moreover, the sensor is arranged in air communication with the pressure box, such as to allow the differential pressure sensor to identify the pressure difference between the air pressure in the pressure box and the fluid pressure in the flow channel.

Flow channel pressure measurement

In an example, a printer controller is coupled to a fluid pump, a primer pump, and a pressure sensor of a printer, wherein a flow channel provides a fluid communication between the fluid pump and the printhead for enabling fluid recirculation in the printer. The printer controller: activates the fluid pump; activates the primer pump for a first predefined time interval; and identifies or determines a movement of fluid in the flow channel based on the fluid pressure measured by the pressure sensor.

Recirculation of a fluid in a printer

An example printing fluid container () comprising a container body () defining a cavity (), and a piston () located within the cavity (), is described. The piston () divides the cavity () into a first chamber () to receive printing fluid and a second chamber (), fluidically isolated from the first chamber (), to receive a positively pressurized fluid.

Printing fluid container

A printing apparatus, a printing system and a method are disclosed. The method of moving printing fluid within a printing apparatus includes selectively providing a first pressure difference between a first reservoir and a second reservoir by a differential pressure system to cause the printing fluid to move from the first reservoir through a printing fluid applicator to the second reservoir. The method also includes selectively providing a second pressure difference between the first reservoir and the second reservoir by the different pressure system to cause the printing fluid to move from the second reservoir through the printing fluid applicator to the first reservoir.

Selectively provide pressure differences between reservoirs to cause printing fluid movement

A printing fluid delivery system includes a reservoir, a conduit system, and a first heating module. The reservoir may store printing fluid. The conduit system may include a plurality of conduit segments to transport the printing fluid between the reservoir and the printing fluid applicator. The first heating module may selectively heat one conduit segment to increase a temperature of the printing fluid therein to a first temperature which is greater than a second temperature of the printing fluid in an other conduit segment, and to thermally induce recirculation of the printing fluid.

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Sant Cugat del Valles, Spain

Joan-Albert Miravet Jimenez