Rotary encoder error compensation system and method for photoreceptor surface motion sensing and control

A method for compensating for rotary encoder error in a marking device with a rotary encoder coupled to a rotating element, the rotary encoder and rotating element forming a pair having a known rotary encoder error, the method comprising:

• providing an amplitude and phase of the known rotary encoder error in a memory;
• detecting a position of the rotating element with the rotary encoder that generates an encoder signal;
• obtaining a normalized error correction value corresponding to the detected position of the rotating element indicated by the encoder signal based on the phase of the known rotary encoder error with an error correction logic circuit linked to the rotary encoder;
• and
• generating a corrected encoder signal based on the encoder signal and the normalized correction value.

A rotary encoder error compensation system for use in a device with a rotary encoder that generates an encoder signal indicating a detected position of a rotating element, the rotary encoder and rotating element forming an encoder pair that has a known rotary encoder error, the compensation system comprising:

• a memory that stores an amplitude and phase of the known rotary encoder error;
• and
• an error correction logic circuit that receives that encoder signal from the rotary encoder,
• wherein the error correction logic circuit obtains a normalized sine value for an angle offset 180 degrees from the known phase of the rotary encoder error at the detected position of the rotating element and generates a corrected encoder signal by multiplying the obtained sine value by the corresponding known amplitude of the rotary encoder error at the detected position.