Independent adjustment of drop mass and drop speed using nozzle diameter and taper angle

A method for forming a printhead nozzle, comprising:

• selecting a desired volume of an ink drop to be ejected from the printhead nozzle;
• selecting a desired drop speed for the ink drop to be ejected from the printhead nozzle;
• designing the printhead nozzle to include a taper that extends from an inside opening at an inside surface of a cover plate to an exit opening at an outside surface of the cover plate;
• selecting a diameter of the exit opening between about 10 μm to about 40 μm to correspond to the selected ink drop volumes;
• selecting an angle of the taper of the nozzle between about 15° and 45° to correspond to the selected drop speed for the ink drop;
• and
• forming the nozzle within the cover plate,
• wherein the drop speed for the ink drop ejected from the printhead nozzle increases linearly from about 0 m/s to about 15 m/s as the taper angle increases from 15° up to 45° and the exit diameter is selected to be between about 10 μm to about 40 μm, and
• wherein the the volume of the ink drop increases by 6 pL or less when the taper angle increases from 15° up to 45° and the exit diameter is selected to be between about 10 μm to about 40 μm.