Error Correction in Printing Systems

A method of error correction in a duplex printing system comprising:

• performing a calibration of a perfector arm with respect to a base structure, said calibration comprising:
• detecting motion of said perfector arm through an integer number of rotations using a homing sensor, said integer number of rotations corresponding to one rotation of a belt, said belt connecting said perfector arm to a drive motor having an encoder;
• and
• differencing actual encoder counts required to produce a motion of said perfecter arm within said integer number of rotations with an expected encoder count to produce a belt position dependent error;
• and
• compensating for said belt position dependent error when feeding a sheet of print media with said perfecter arm in said duplex printing system.

A duplex printing system comprising:

• an impression cylinder configured to hold a sheet of print media on a surface of said impression cylinder;
• a perfector arm, said perfector arm being configured to engage said sheet of print media, remove said sheet of print media from a surface of said impression cylinder, and reposition said sheet of print media on said impression cylinder such that an opposite side of said sheet of print media is presented for printing, said perfecter arm being connected to a drive motor by a belt, said drive motor being configured to control motion of said perfector arm;
• and
• a homing sensor configured to detect passage of said perfecter arm while said perfector arm is engaged with said sheet of print media.