Drop characteristic measurement

A printing system, comprising:

• a base;
• a substrate support supported on the base;
• and
• a print assembly supported on the base, the print assembly comprising:
• a dispenser support extending across the substrate support;
• and
• a dispenser assembly movably coupled to the dispenser support;
• and
• a droplet measurement apparatus supported on the base, the droplet measurement apparatus comprising:
• a housing;
• a light source disposed in the housing, the light source comprising a collimating optical system;
• an imaging device disposed to receive light from the collimating optical system;
• a droplet illumination zone;
• a steering optic that defines an optical path of light emitted by the light source and received by the imaging device;
• and
• a droplet receptacle, wherein a portion of the optical path is directed through the droplet illumination zone across the droplet receptacle and the imaging device has an adjustable working range to vary a focal plane along the portion of the optical path.

A printing system, comprising:

• a base;
• a substrate support supported on the base;
• and
• a print assembly supported on the base, the print assembly comprising:
• a dispenser support extending across the substrate support;
• and
• a dispenser assembly movably coupled to the dispenser support;
• and
• a droplet measurement apparatus supported on the base, the droplet measurement apparatus comprising:
• a housing;
• a light source disposed in the housing, the light source comprising a collimating optical system;
• an imaging device disposed to receive light from the collimating optical system;
• a droplet illumination zone;
• a steering optic that defines an optical path of light emitted by the light source and received by the imaging device;
• and
• a droplet receptacle, wherein a portion of the optical path is directed through the droplet illumination zone across the droplet receptacle and the imaging device has a lens with adjustable focal length, a linear positioner, or both to vary a focal plane along the portion of the optical path.