Print material reservoir, printhead assembly and inkjet printer

A printhead assembly for an inkjet printer, the printhead assembly comprising:

• a housing;
• at least one printhead supported by the housing, and comprising a plurality of nozzles from which a print material is to be ejected;
• and
• a fluid recirculation circuit at least partially supported by the housing to recirculate the print material to and from the at least one printhead,
• wherein
• the fluid recirculation circuit comprises at least one reservoir to contain an amount of the print material being recirculated through the fluid recirculation circuit, and
• the at least one reservoir is supported by the housing, and comprises a sensor to detect a weight of the print material contained in the reservoir.

An inkjet printer, comprising:

• a substrate support;
• a printhead assembly support;
• and
• a printhead assembly coupled to the printhead assembly support and moveable along the printhead assembly support in a first direction,
• wherein
• the printhead assembly comprises:
• at least one printhead comprising a plurality of nozzles from which a print material is to be ejected toward the substrate support, and
• a reservoir coupled to the at least one printhead to supply the print material to the at least one printhead or to receive the print material returned from the at least one printhead,
• the reservoir comprises a load cell having a beam deformable under a weight of the print material contained in the reservoir, and
• the beam extends along a second direction transverse to the first direction.