CPC B41J 2/04558 (2013.01) [B41J 2/04586 (2013.01); G01N 9/00 (2013.01)] | 11 Claims |
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.
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