Liquid Dispenser Cassette

A liquid dispenser cassette, comprising:

• a frame defining a recess, the recess defining openings;
• dispense head assemblies seated in the recess, each dispense head assembly comprising:
• a substrate;
• a dispense head die mounted on the substrate, the dispense head die comprising:
• a top slot;
• and
• downward nozzle array exposed through a corresponding opening;
• and
• a set of electrical contact pads on the substrate coupled to the dispense head die;
• a one-piece integrated slot extender mounted on dispense head dies along the length of the recess so sets of electrical contact pads remain exposed, the slot extender comprising reservoirs defining drain openings mated to corresponding top slots, each reservoir having a capacity equal to or greater than 20 microliters.