Hewlett-packard Development Company, L.p.

Marta Coma Vives

Antonio Gracia Verdugo

David Butinya

Mauricio Seras Franzoso

Albert Crespi Serrano

Gonzalo Gaston Llado

David Butinya Teixido

Macia Sole Pons

Xavier Gasso Puchal

Joan Albert Jorba Closa

Ezequiel Jordi Rufes Bernad

Ana Cristina Garcia Alvarez

Macia Solé Pons

Emilio Angulo Navarro

Xavier Gros

Jose M Rio Doval

Alex Andrea Tallada

Jordi Hernandez Creus

Barret Kammerzell

Joan-Albert Miravet Jimenez

Maria Dinares Argemi

Francesc Melia Sune

Xavier Gros Gras

Joan Albert Miravet Jimenez

Joan-Albert Miravet

Ángel Martínez Barambio

Jorge Millan Lafuente

Javier Chavarria Roe

Pol Vinardell

María Dinares Argemi

Xavier Gras Gros

Daniel Callejo

Guillem Montero Costa

Macia SolÉ Pons

An example printing fluid circulation system includes a first circuit to circulate a printing fluid through a printhead in a first direction and a second circuit to circulate the printing fluid through the printhead in a second direction opposite to the first direction. The first circuit is activated during a first mode to circulate the printing fluid from a first reservoir to a second reservoir. The second circuit is activated during a second mode different from the first mode to circulate the printing fluid from the first reservoir to the second reservoir.

Printing fluid circulation

A printing apparatus is disclosed. The printing apparatus comprises a rotating housing comprising a wall with an inner side defining a chamber and an outer side. The wall has a bore communicating the inner side and the outer side, and the chamber is to receive a fluid container. The printing apparatus also comprises a fix frame holding the rotating housing. The printing apparatus further comprises an optical sensor comprising an emitter to issue a detecting optical signal through the bore and a receiver to receive a detected optical signal associated to the detecting optical signal. The detected signal is sent to a controller to determine whether the fluid container is present in the rotating housing.

Rotating housing with sensor

A printing device and method is described comprising: selectively generating a negative fluid pressure between one of one or more printing fluid supplies and a first one of first and second ports of a printhead; selectively generating a positive fluid pressure between one of said printing fluid supplies and a second one of the first and second ports of the printhead; and providing a first pulsed signal to a first priming pump associated with a first one of the first and second ports, wherein the first one of said first and second ports of the printhead is opened under the control of said first priming pump, such that printing fluid within the printhead exits the printhead through the first one of the first and second ports.

Printing fluid recirculation

A device includes a fluid channel connecting a pair of ports and an attachment feature to attach the device at a dummy cartridge; wherein the pair of ports is dimensioned to mate with fluid feed ports of a printer when the device is attached to the dummy cartridge and the dummy cartridge is inserted in the printer.

Dummy cartridge accessory device

An example printing fluid circulation circuit for a printing system comprises a first circuit port to supply printing fluid to, or receive printing fluid from, a first fluid port of a printhead and a second circuit port to supply printing fluid to, or receive printing fluid from, a second fluid port of a printhead. The printing fluid circulation circuit is to operate in a first mode to concurrently supply printing fluid from the first reservoir to the first circuit port and from the second circuit port to a second reservoir, and in a second mode to concurrently supply printing fluid from the first reservoir to the second circuit port and from the first circuit port to the second reservoir.

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

Fluid supply apparatusis disclosed. The fluid supply apparatuscomprises a first conduitto supply fluid to a fluid dispense head and a second conduitto receive fluid from the fluid dispense head. The first conduitand second conduitmay both supply print fluid to a print head in a printing or servicing configuration. The first conduitand the second conduitare coupled together via a closable third conduit. The closable third conduitpermits fluid flow between the first conduitand the second conduit. The third conduitcomprises deformable walls movable towards each other to close the third conduitto the passage of fluid between the firstand second conduit

Deformable fluid supply

A printing device comprises a printing fluid supply; a plurality of printheads connected in parallel to the supply by a first flow path and a second flow path; a first fluid pressure source to create a negative fluid pressure between the supply and the first openings; a second fluid pressure source to create a positive fluid pressure between the supply and the second openings; and a controller. Each printhead comprises a closable first opening connected to the first flow path and a closable second opening connected to the second flow path, and has an associated mechanism to increase a fluid pressure in the printhead. Each first opening is to open in response to operation of the associated mechanism. The controller is to identify a first printhead for which printing fluid in the first printhead is to be recirculated; and operate the mechanism associated with the identified printhead.

Herein is disclosed an ink storage unit. The ink storage unit may comprise first and second reservoirs, each having a variable internal volume; a transfer system to transfer ink between the first and second reservoirs such that as ink is transferred from the first reservoir to the second reservoir, the internal volume of the first reservoir decreases and the internal volume of the second reservoir increases.

Ink storage unit having variable volume reservoirs

Example methods for the maintenance of printheads are provided, the printheads comprising a reservoir containing a printing fluid with particles in suspension, and a nozzle plate. Example methods may comprise capping the nozzle plate of the printhead, and rotating the capped printhead. Example maintenance devices for printheads are also provided, comprising a support with a socket to attach a printhead to the support, a drive unit to rotate the support about a rotation axis, and a control unit connected to the drive unit to perform a predetermined rotation cycle.

Printhead maintenance

In an example, a printhead-wiping device comprises: a wiper element and a biasing mechanism, the biasing mechanism to bias the wiper element towards a printhead. An actuator may be used to adjust a preload force applied to the biasing mechanism. The preload force applied to the biasing mechanism may be controlled using a controller so as to control a wiping force applied by the wiper element against the printhead.

Printhead-wiping device

A printing fluid circulation system is described. The system comprises first and second reservoirs, an outlet to supply printing fluid to a fluid inlet of a printhead, an inlet to receive printing fluid from a fluid outlet of the printhead, and a supply system. The supply system is to operate in a first mode to concurrently supply printing fluid from the first reservoir to the outlet and from the inlet to the second reservoir, and in a second mode to concurrently supply printing fluid from the second reservoir to the outlet and from the inlet to the first reservoir.

In one example, a structure to hold a printhead includes a surface defining an opening through which the printhead orifices may be exposed for printing and a replaceable shield shielding an area of the surface around the opening.

Replaceable shield for a printhead

Examples associated with drop velocity aberrancy detection are disclosed. One example includes firing ink through nozzles of a print-head past sensors to identify drop velocities of the nozzles. A target drop velocity is selected based on the drop velocities of the nozzles. An aberrant nozzles is detected when a nozzle has a drop velocity that deviates from the target drop velocity by a selected threshold. The aberrant nozzle is deactivated, and a good nozzle that will travel over locations traversed by the aberrant nozzle is configured to print portions of a job that would have been printed by the aberrant nozzle.

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Barcelona, Spain

Marta Coma Vives