Maximizing speed tolerance during dual engine synchronization

A method of synchronizing the timing of a plurality of physically coupled print engines by minimizing primary imaging member timing errors that are misleading indications during synchronization, the method comprising:

• determining a target time using a position of one or more timing marks on a first primary imaging member in a first print engine having a first timing;
• directing a receiving sheet from the first print engine to a second primary imaging member in a second print engine having a second timing;
• calculating a nominal arrival time of the receiving sheet relative to a fixed position in the second print engine;
• measuring an actual timing variation using the nominal arrival time of the second print engine and the target time in the first print engine;
• determining if the actual timing variation is within a predetermined error tolerance and if not, an error is flagged as an error limit;
• measuring an additional actual timing variation of one or more sequential frames of the second print engine;
• and
• summing the absolute values of two or more actual timing variations to yield a total timing variation and if the total timing variation does not exceed a total timing tolerance, generating a signal not to use the information that generated the error limit.

An electrophotographic print apparatus including a plurality of physically coupled print engines that minimize errors due to misleading indicators during synchronization, the apparatus comprising:

• a plurality of coupled electrophotographic print modules, each module including a primary imaging member, wherein the position of the primary imaging member in a second print engine is synchronized to the position of the primary imaging member in a first engine by a signal generated by the first print engine;
• a comparator to compare a target time, using a position of one or more timing marks on a first primary imaging member in a first print engine having a first timing, to a nominal arrival time the receiving sheet arrives at a fixed position in the second print engine;
• to measure a variation of the actual timing using the nominal arrival time of the second print engine from the target time in the first print engine;
• an error flag that is activated if it is determined the timing is outside the predetermined error tolerance, the error is flagged an error limit;
• a counter that counts the error limits to yield a total an error limit number and if the error limit number exceeds a timing tolerance, generating a signal not to use the information that generated the error limit.