Paper driven rotary encoder that compensates for nip-to-nip handoff error

摘要

A sheet transport system has an encoder roller in direct contact with the sheet media and driven by the sheet media to detect and compensate for any registration error particularly at lead and trail edges during transport of the sheet media as media enters and exits transport nips. The invention is well suited for use in controlling and monitoring paper movement in incremental advance and print systems, such as ink jet printers. A biasing member ensures that the sheet media and encoder roller are in intimate contact. Preferably, a material with a high coefficient of friction is provided on an outer periphery of the encoder roller to assist in mating of the roller with the sheet media.