Browse Prior Art Database

Overfeed Alarm for Control System

IP.com Disclosure Number: IPCOM000085919D
Original Publication Date: 1976-Jun-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Chien, JH: AUTHOR [+2]

Abstract

A system for control of toner feed in an electrophotographic machine is described.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 100% of the total text.

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Overfeed Alarm for Control System

A system for control of toner feed in an electrophotographic machine is described.

Toner feed in an electrophotographic machine is usually based on the sensing of a control parameter. However, malfunctions may occur that cause invalid sensing of the control parameter and, therefore, overfeeding of toner is a possibility.

An alarm system is described to override the normal control to prevent overflow or other serious conditions from occurring. The alarm system adds a strobe which occurs each time the output level of the sensor is compared with a reference level. A "feed" pulse is generated only when the sensor level is low. Since there is some delay between feeding and sensing the increased level, normal operation consists of several feed pulses followed by several missing pulses.

If a malfunction occurs, every strobe produces a feed pulse. The maximum number of consecutive feed pulses (M) is determined empirically and then a number N (M plus a latitude factor) is loaded into a counter. The counter is counted down one for each strobe pulse and the counter is reset for each "no feed" signal. If a reset does not occur within N strobes, the overfeed alarm is set. The operation can be further improved by the addition of a factor to vary N based on the predicted use rate.

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