Browse Prior Art Database

Encoder Predictor

IP.com Disclosure Number: IPCOM000082871D
Original Publication Date: 1975-Feb-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 53K

Publishing Venue

IBM

Related People

Bruns, DG: AUTHOR [+4]

Abstract

This apparatus is for determining accurate paper movement when pin-feed encoding of the carrier strip holes is impractical. The paper movement is predicted by position information from the paper drive roll encoder. This prediction is checked periodically and corrected, if necessary, by hole sense information obtained from a photo-optic sensor provided to read tractor holes in the carrier strip of the paper. There may be missing or extra holes in the carrier strip so that to accurately keep track of paper movement, the missing and extra holes are accounted for through the predictor circuit.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 69% of the total text.

Page 1 of 2

Encoder Predictor

This apparatus is for determining accurate paper movement when pin-feed encoding of the carrier strip holes is impractical. The paper movement is predicted by position information from the paper drive roll encoder. This prediction is checked periodically and corrected, if necessary, by hole sense information obtained from a photo-optic sensor provided to read tractor holes in the carrier strip of the paper. There may be missing or extra holes in the carrier strip so that to accurately keep track of paper movement, the missing and extra holes are accounted for through the predictor circuit.

The predictor circuit utilizes as an input the output of a shaft angle encoder which is mechanically coupled to the paper feed drive. The encoder produces several pulses during the movement of the paper from one tractor hole to the next. The encoder produces pulses at a rate of movement of nominal 16.5 pulses per inch. The spacing of tractor holes in the carrier strip is 1/2 inch apart.

The encoder pulses are counted in the fine encoder counter and when the count equals eight, 1/2 inch of paper movement is predicted. The count in the fine encoder counter is checked when a hole is sensed in the carrier strip. If the counter equals eight when the hole is sensed, then the paper movement is in step with the predicted movement. If the count is not eight, one is added or subtracted to bring the counter closer to eight.

Controls are provided so that if one is added t...