Stepper motor automated self-test routine
AssigneeXerox Corporation
InventorsRobert P. Siegel, Kevin E. Price
Life of this patent
Estimating the term…
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.
Claims9
A method for diagnosing degradation of stepper motors, comprising the steps of:
- a) identifying a stepper motor to be tested;
- b) applying a predetermined frequency to the stepper motor that is greater than the nominal starting frequency for the stepper motor;
- c) observing if the stepper motor starts;
- d) recording the frequency if the motor starts as the start frequency;
- e) decreasing the frequency to the stepper motor in predetermined increments if the motor does not start in step c);
- f) observing if the stepper motor starts after each decreasing frequency;
- and
- g) correlating the responses to the aging life of the stepper motor.
A method for diagnosing degradation of stepper motors, comprising the steps of:
- a) identifying a stepper motor to be tested;
- b) applying a predetermined current to the stepper motor that is less than the nominal rated starting current for the stepper motor;
- c) observing the current when the stepper motor starts;
- d) increasing the current to the stepper motor in predetermined increments if the stepper motor does not start in step c);
- e) observing when the stepper motor starts for each of said predetermined increments;
- and
- f) analyzing the starting currents and generating a signal to replace the stepper motor when the required current comes within or falls outside a predetermined tolerance of the nominal starting current for the stepper motor.
A method for diagnosing whether a stepper motor is functioning properly, comprising the steps of:
- a) identifying a stepper motor to be tested;
- b) providing a paper sensor downstream of said stepper motor;
- c) feeding a sheet from a tray;
- d) stopping the sheet in a predetermined location upstream of said paper sensor within a nip that is driven by said stepper motor;
- e) applying a predetermined current to said stepper motor that is less than its standard operating current;
- f) starting a timer;
- g) monitoring said paper sensor to determine state change indicating arrival of the sheet at said sensor within a predetermined time;
- h) recording motor start time;
- and
- i) storing said motor start current for trend analysis.
Dependencies are inferred from the claim text.