Circulating fluid for fluid droplet ejecting

A fluid droplet ejection apparatus comprising:

• a printhead having a fluid supply and a fluid return;
• and
• a substrate attached to the printhead, the substrate having a fluid inlet and a fluid outlet on a surface of the substrate proximate to the fluid supply and the fluid return, and nozzles in fluid communication with the fluid inlet,
• wherein the fluid inlet of the substrate is in fluid communication with the fluid supply and the fluid outlet is in fluid communication with the fluid return,
• wherein a first circulation path through the substrate is between the fluid inlet and the fluid outlet,
• wherein the fluid supply is in fluid communication with the fluid return through a second circulation path that is through the printhead and not through the substrate,
• the apparatus comprises a fluid path configured such that a fluid flowing along the fluid path splits and flows simultaneously into the first circulation path and the second circulation path when flowing from the fluid supply to the fluid return.