초록 ▼

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

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.

대표청구항 ▼

[ What is claimed is:] [1.] Apparatus for regulating sheet media position within a sheet media transport path formed between an upstream transport nip and a downstream transport nip that compensates for error in sheet media positioning, at least one of the upstream and downstream nips being driven b

[ What is claimed is:] [1.] Apparatus for regulating sheet media position within a sheet media transport path formed between an upstream transport nip and a downstream transport nip that compensates for error in sheet media positioning, at least one of the upstream and downstream nips being driven by a drive mechanism, the apparatus comprising:an encoder roller rotatably mounted between the upstream transport nip and the downstream transport nip so as to contact one side of a sheet media fed through the sheet media transport path, the encoder roller having an outer peripheral surface at least partly formed from a high coefficient of friction material and further including an encoder member that measures angular rotation of the encoder roller;a biasing member positioned along the transport path between the upstream transport nip and the downstream transport nip at a location that biases the sheet media against the encoder roller, a combination of the high coefficient of friction material on the encoder roller and a biasing force of the biasing member being selected to prevent relative slip between the sheet media and the encoder roller and cause the encoder roller to be driven solely by a driving force generated by the sheet media as it is transported along the transport path;a controller that determines sheet media misregistration by comparing output from the encoder roller with predicted registration; andan adjustment mechanism that compensates for any misregistration.