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Compensation for Gear and Stepper Motor Errors

IP.com Disclosure Number: IPCOM000060193D
Original Publication Date: 1986-Mar-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Troupes, D: AUTHOR

Abstract

In a printer, inaccurate paper advance is a problem and, generally, it can be attributed to the gear tolerance or the stepper motor. In some printers, a stepper motor, which is coupled to the paper advance mechanism with a set of gears, advances the paper. A knob is also attached to the mechanism for manual paper advance. The stepper motor, upon receiving an appropriate signal, advances the paper 1/144 inch. There is a certain amount of tolerance built into the gears. The tolerance can vary from a fraction of a step to as high as a few steps. The gear tolerance does not cause any problem as long as the paper in the printer is advanced in the same direction. When the paper direction is changed, then the first line increment, following a direction change, will be off by the amount of the gear tolerance.

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Compensation for Gear and Stepper Motor Errors

In a printer, inaccurate paper advance is a problem and, generally, it can be attributed to the gear tolerance or the stepper motor. In some printers, a stepper motor, which is coupled to the paper advance mechanism with a set of gears, advances the paper. A knob is also attached to the mechanism for manual paper advance. The stepper motor, upon receiving an appropriate signal, advances the paper 1/144 inch. There is a certain amount of tolerance built into the gears. The tolerance can vary from a fraction of a step to as high as a few steps. The gear tolerance does not cause any problem as long as the paper in the printer is advanced in the same direction. When the paper direction is changed, then the first line increment, following a direction change, will be off by the amount of the gear tolerance. However, the printer control unit can compensate for the error as long as the paper is advanced by the stepper motor. However, when the operator elects to adjust the paper manually then the first line increment may be off by the amount of the gear tolerance. In this case, the printer control unit cannot compensate for the tolerance because it is not aware that the paper has been moved. Besides the error attributed to the gear tolerance, an additional error can be caused by the stepper motor when the paper is moved manually. The printer control unit keeps track of the stepper motor phases until the paper is moved manually when it loses track of the phases. Thus, when a four-phase s...