Patent ID: 7077492

Claim:
An inkjet printer having an optical sensor device with sensor compensation, the device comprising: an optical emitter emitting an optical signal of an optical signal level according to an emitter input from an electric source; an optical detector disposed to detect the optical signal and output a detector output having an output metric according to the detected optical signal, the output metric being a voltage level, a voltage drop, or a detection trigger level; a variable attenuator having an adjustable attenuation setting to provide a variable sensitivity to the optical sensor device; and a controller adjusting the attenuation setting of the variable attenuator during an adjustment operation to adjustably vary the variable sensitivity of the optical sensor device, determining the attenuation setting at which the output metric of the detector output exceeds a predetermined value, and accordingly setting the variable attenuator at an attenuation setting to operate the detector output with the output metric better than the predetermined value by a margin.