Patent ID: 8731415

Claim:
A method for determining a relative amount of waste toner in a waste toner box of an imaging apparatus comprising: measuring voltages at a beginning and an end of each of a plurality of intervals, each of the measured voltages corresponding to a capacitance within the waste toner box that varies with an amount of waste toner in between a pair of separated plates; determining a relative change in capacitance based on the voltages measured, the relative change in capacitance being determined by: calculating a difference between the voltages measured at the beginning and the end of each of the plurality of intervals; and dividing each voltage difference by a divisor value to determine the relative change in capacitance; comparing the determined relative change in capacitance with a predetermined threshold value to determine the relative amount of waste toner in the waste toner box; identifying a first number of pages corresponding to a number of pages printed from a time the waste toner box is empty to a time when the relative amount of waste toner in the waste toner box is initially determined to be nearly full; identifying a second number of pages corresponding to a number of pages printed from the time the waste toner box is empty to a time after the relative amount of waste toner in the waste toner box is initially determined to be nearly full; comparing the second number of pages with a sum of the first number of pages and a predetermined full page delta; and when the second number of pages is greater than the sum of the first number of pages and the predetermined full page delta, determining the relative amount of waste toner in the waste toner box as being full.