Inkjet printhead with grouped nozzles and a nozzle guard

1. A printhead for inkjet printing, the printhead comprising:

a substrate;

a plurality of nozzles arranged on the substrate in groups, the substrate defining groups of ink supply passages to supply an ink of a particular color to respective nozzles of each group;

a nozzle guard arranged with respect to the nozzles to define a space between the nozzle guard and the nozzles, the nozzle guard defining a plurality of passages with each passage being in register with a respective nozzle so that each nozzle can eject the ink across the space and through a respective passage; and

an ink supply member mounted on the substrate and which defines channels in fluid communication with respective groups of ink supply passages, the ink supply member having a plurality of ink inlet openings in fluid communication with respective channels, the ink inlet openings being separated by transversely extending beads of sealing material to isolate the ink inlet openings from each other when the printhead is mounted.

2. A printhead as claimed in claim 1 , wherein the substrate comprises a silicon wafer in which the plurality of ink supply passages is defined.

3. A printhead as claimed in claim 1 , in which the groups comprise rows of nozzles and corresponding passages in the nozzle guard.

4. A printhead as claimed in claim 1 , wherein an air supply is arranged to supply air into the space between the nozzle guard and the nozzles.