US 11,833,815 B2
Coatings for optical drop detectors
Jordan David Spangler, Corvallis, OR (US); and Eric Thomas Martin, Corvallis, OR (US)
Assigned to Hewlett-Packard Development Company, L.P., Spring, TX (US)
Appl. No. 17/416,544
Filed by Hewlett-Packard Development Company, L.P., Spring, TX (US)
PCT Filed Jun. 8, 2019, PCT No. PCT/US2019/036186
§ 371(c)(1), (2) Date Jun. 21, 2021,
PCT Pub. No. WO2020/251517, PCT Pub. Date Dec. 17, 2020.
Prior Publication US 2022/0097366 A1, Mar. 31, 2022
Int. Cl. B41J 2/045 (2006.01); G01N 9/00 (2006.01)
CPC B41J 2/04558 (2013.01) [B41J 2/04586 (2013.01); G01N 9/00 (2013.01)] 11 Claims
OG exemplary drawing
 
1. An apparatus comprising:
a printhead to dispense drops of print fluid on a media, wherein the drops travel along a drop path through air from the printhead;
a light source to emit light across the drop path;
a detector to detect an intensity of the light received from the light source, wherein the drop path intersects an optical path from the light source to the detector; and
a coating disposed on the optical path between the drop path and the detector, wherein the coating is to absorb a threshold amount of the light with a specified energy;
wherein the specified energy is tunable by a voltage applied across the coating, wherein the voltage adjusts a band gap of the coating.