Patent ID: 7433612

Claim:
A timing wheel assembly that controls timing of a toner cartridge comprising: a timing wheel base fixedly mounted on a shaft operatively connected to a toner tank agitator assembly that rotates on an axis; a main drive gear mounted on the axis that rotatably dwells within a predetermined arcuate range between a first stop and a second stop with respect to the timing wheel; a first spring having a first spring constant operatively connected to each of the main drive gear and the timing wheel; a second spring having a second spring constant greater than the first spring constant operatively connected to each of the main drive gear and the timing wheel; and wherein each of the first spring and the second spring are constructed and arranged so that the first spring applies a rotational resistance force between the main drive gear and the timing wheel at a first level of rotational resistance applied by the agitator assembly as the agitator assembly passes through toner and the second spring applies a second level of rotational resistance greater than the first level after the timing wheel rotates past a predetermined arcuate position under rotational resistance from the first spring.