Apparatus and method for predicting failure in a copier's paper path

• US 4,589,080 A
• Filed: 06/11/1982
• Issued: 05/13/1986
• Est. Priority Date: 06/11/1982
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Abbott, Jerry J., Herring, Greg S., Bobo, Keith N., Bierschbach, James E.
• Primary Examiner(s): Thomas, James D.
• Assistant Examiner(s): Shaw, Dale M.
• Application Number:
  US06/387,722
• Time in Patent Office: 1,432 Days
• Field of Search: 364/550-552, 364/554, 364/523, 371/20, 355/14 R, 377/8
• US Class Current: 702/183
• CPC Class Codes: G03G 15/55 Self-diagnostics; Malfunction or lifetime display

Abstract

Selected points in a copier are monitored by signal lines connected to a computer. If a signal is detected on a signal line, the time of occurrence is stored in the computer'"'"'s memory at a location associated with the point that caused the signal. Eventually an array of the times of operation of each monitored point will be stored. The computer then calculates the difference between the times stored for selected pairs of the monitored points and stores these, as intervals, in additional locations of the memory. The intervals are combined to give calculated statistical results (mean, deviation, etc.) each of which is then compared against predetermined values normal for correctly operating copiers also stored in the memory. The results of the comparison set error flags if the limits are exceeded indicating possible future copier failures.

Claims

1. A method for predicting and identifying failure of an electrophotographic copier before a failure occurs, comprising the steps of:

monitoring selected signal-supply points of the copier;

detecting the occurrence of signals at the selected points;

timing detected signals;

assigning to individual detected signals current digital time values representing the time at which the signal occurred;

storing digital values including a plurality of preselected digital limit values representing copier operational limits;

calculating differences between chosen pairs of current digital time values;

storing the differences as digital difference values;

generating digital statistical values, representing averages and variances as a function of the stored digital difference values;

storing the generated digital statistical values;

comparing one by one, digital statistical values representing averages and variances with digital limit values representing copier operational limits corresponding to said values;

storing as digital result values the results of the comparisons; and

signaling as a potential failure each stored digital result value representing an average or variance exceeding its corresponding copier operational limit.

2. A method for predicting and identifying failure of a copier before a failure occurs, comprising the steps of:

monitoring points of the copier and detecting the occurrence of signals at the points;

timing detected signals and assigning to individual detected signals values representing the time at which the signal occurred;

storing values including a plurality of preselected limit values representing copier operational limits;

calculating differences between chosen pairs of time values and storing the differences as difference values;

generating statistical values, representing averages and variances as a function of the stored difference values and storing the generated statistical values;

comparing one by one, statistical values representing averages and variances with limit values representing copier operational limits, and storing as result values the results of the comparisons; and

signaling as a potential failure each stored result value representing an average or variance exceeding its corresponding copier operational limit.

3. A method for predicting and identifying failure of a copier before failure occurs comprising the steps of:

monitoring signals from the copier;

assigning to signals values representing the times at which the signals occurred;

determining differences between pairs of time values;

generating statistical values, representing averages and variances, as a function of the differences;

comparing one by one, statistical values with limit values representing corresponding copier operational limits; and

signaling as a potential failure each value representing an average or variance exceeding its copier operational limit.