Stepper motor automated self-test routine

Abstract

A printing apparatus includes a stepper motor automated self-test routine that gives an approximation of the state of the degradation of the stepper motor and/or its driven load. The test includes artificially increasing the starting frequency above normal and/or reducing the operation current below normal by a known and controllable amount to the stepper motor and tracking the level at which the motor is just able to start operating. By examining the magnitude and/or change in these levels, the remaining life and reliability of the motor can be predicted. Alternatively, the self-test routine could be used in conjunction with paper path sensors to determine the start time for a stepper motor. The start times are stored for trend analysis.

Dependencies are inferred from the claim text.