| 摘要 |
An integrated circuit chip with digital and analog circuits thereon for providing a low cost infrared reflectance densitometer for detecting relative toner density on a photoreceptive surface including several stages of calibration including photodiode detection means 208 for monitoring and controlling the light output from a light emitting diode 206, photodiode means 302 for detecting undesired scattered and reflected background light signals, further photodiode means 304 for detecting the light reflected from said photoreceptive surface as may be affected by toner deposited thereon, an automatic gain control circuit 400 for automatically adjusting the output gain of the reflectance densitometer, and sample and hold circuit means 600 for adjusting the circuit for different effects of the aging, leakage current effects, or other undesired performance characteristics of the circuit components.
|
