ADC DIAGNOSTIC DEVICE
Original Publication Date: 1976-Oct-31
Included in the Prior Art Database: 2004-Mar-27
Xerox Disclosure Journal
Circuit 12 indicates the proper operation of an automatic developability control system employed in an electrophoto- graphic printing machine0 A signal from a photosensor is transmitted on line 10 to circuit 12. A plurality of rows connected in parallel to one another comprise zener diodes 14a, 14b, l4c, light emitting diodes l6a, l6b, l6c, and limiting resistors 18. Each zener diode has a decreasing voltage level, i.e., the zener diode 14a has a value of 16 volts, zener giode l4b, 15 volts, and zener diode l4c, 14 volts. Light emitting diodes l6a, l6b, l6c will all be energized indicating a voltage at point 20 greater than 16 volts. If the peak voltage is between 15 and 16 volts, diode l6b and diode 16c are illuminated, if the value of point 20 is between 14 and 15 volts, diode l6c will flash. If the value of point 20 is less than 14 volts, all of the diodes will remain darkened, In this manner, circuit 12 provides a good indication of the detected output from the photosensor of the automatic developability control circuit.