Hewlett-packard Development Company, L.P.

Tuomo Eljas Kaikkonen

Albert Crespi Serrano

Miquel Boleda Busquets

David Butinya Teixido

Jorge Castano Aspas

Secundino Vicente Vicente

Yngvar Rossow Sethne

Oriol Parera Fiestas

Certain examples relate to controlling recirculation processes in a printing apparatus. An example printing material cartridge includes a reservoir storing printing material to supply a printing apparatus; memory; and instructions for controlling a recirculation process in the printing apparatus, the instructions stored in the memory, the recirculation process to cause the printing material to move between the reservoir and a second printing material cartridge, the second printing material cartridge separately replaceable from the printing material cartridge in the printing apparatus.

Printer recirculation control

Certain examples relate to mixing and/or supply cartridges for printing apparatus. One example implementation includes a reservoir to receive printing material from a printing apparatus and to return the received printing material to the printing apparatus. A storage medium stores a reservoir printing material level parameter indicative of the amount of printing material in the reservoir; a recirculation cycle counter indicative of the number of recirculation events experienced by the cartridge; a maximum recirculation cycle parameter indicative of the maximum number of recirculation events that may be experienced by the cartridge.

Supply and mixing cartridges

An example printing material cartridge includes a reservoir storing printing material to supply a printing apparatus and a storage medium storing process instructions for controlling the recirculation process in the printing apparatus.

Operating a fluid delivering system in a printer, wherein the fluid delivering system comprises a fluid supply including a fluid bag which contains a fluid to be delivered to a fluid delivering tube connected to a printhead, and a closed pressurizing volume which surrounds the fluid bag to expel fluid from the fluid bag to the fluid delivering tube when applying pressure from a pressurizing system to the pressurizing volume, wherein pressure in the pressurizing system relative to atmosphere is measured by a first sensor, and wherein a second sensor provides an output signal which indicates a pressure difference between the pressurizing system and the fluid delivering tube, comprising disconnecting the pressurizing volume of the fluid supply from the pressurizing system, providing a connection of the pressurizing volume to atmosphere to transmit atmospheric pressure to the fluid, generating pressure in the pressurizing system, performing measurements of the pressure in the pressurizing system relative to atmosphere by the first sensor, and calibrating the second sensor by the measurements of the first sensor.

Fluid delivering in a printer

A control system for controlling actuators comprises a central processor, a plurality of actuators, and a plurality of servo systems for controlling the respective actuators. Each servo system is operable, independently of the central processor, to control a controlled parameter (Y) in accordance with a reference value (R). The servo systems and the central processor communicate via a non-deterministic communications system. The central processor and the servo systems provide, to the central processor via the non-deterministic communications system, offset signals representing offsets (R&#x2212;Y) measured by the servo systems between reference R and actual Y values of the controlled parameter. The central processor compares the offsets (R&#x2212;Y) measured by the respective servo systems one with another.

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Sant Cugat del Valles, Spain

Tuomo Eljas Kaikkonen