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PROGRAMMABLE DEVELOPMENT CONTROL SYSTEM

IP.com Disclosure Number: IPCOM000023394D
Original Publication Date: 1977-Aug-31
Included in the Prior Art Database: 2004-Mar-30
Document File: 2 page(s) / 503K

Publishing Venue

Xerox Disclosure Journal

Abstract

In an electrophotographic printing machine, it is desirable to maintain the concentration of toner particles within the developer mix substantially constant to optimize copy quality. A control system for achieving the foregoing is depicted in •the drawing. As shown therein, an"opaque timing wheel has a plurality of slits therein, The timing wheel synchronizes the machine Operation and has two channels of information. One channeL has a slot to indicate the initiation of each machine cycle. The Other channel has a plurality of slots indicating the location of the phôtoconductive drum during each cycle. The timing wheel is mounted' on the shaft of the photoconduc-tive drum and. has a light source positioned on One side there-of with the photosensor being positioned on the other' side thereof. The• tight source is arranged to transmit light rays through the slots • These light rays excite the photosensor which develops a signal' in responSe thereto. Digital filter and multiplex 62 detects the incoming signals and distinguish them free incorrect signals and transients. All inputs are polled and tested. During the 'polling of the signal, the • signal is.tested a plurality of times. A change in the signal in any one of these tests indicates that the signal is unre-liable and the 'signal 'is ignored. If the input signal is the • same for, all of the tests, the information is accepted and multiplexed 'onto an information bus and then decoded 'by

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XEROX DISCLOSURE JOURNAL

PROGRAMMABLE DEVELOPMENT

        Rue afl~
Douglas G. wiggins

Proposed Classification
U.S. Cl. 118/646
tnt. Cl. G03g 15/06

In an electrophotographic printing machine, it is desirable to
maintain the concentration of toner particles within the
developer mix substantially constant to optimize copy quality.
A control system for achieving the foregoing is depicted in
*the drawing. As shown therein, an"opaque timing wheel has a
plurality of slits therein, The timing wheel synchronizes the
machine Operation and has two channels of information. One
channeL has a slot to indicate the initiation of each machine
cycle. The Other channel has a plurality of slots indicating
the location of the phôtoconductive drum during each cycle. The timing wheel is mounted' on the shaft of the photoconduc- tive drum and. has a light source positioned on One side there- of with the photosensor being positioned on the other' side
thereof. The* tight source is arranged to transmit light rays
through the slots * These light rays excite the photosensor
which develops a signal' in responSe thereto. Digital filter
and multiplex 62 detects the incoming signals and distinguish
them free incorrect signals and transients. All inputs are
polled and tested. During the 'polling of the signal, the
* signal is.tested a plurality of times. A change in the signal
in any one of these tests indicates that the signal is unre-
liable and the 'signal 'is ignored. If the input signal is the
* same for, all of the tests, the information is accepted and
multiplexed 'onto an information bus and then decoded 'by

Volume 2' Number 4 July/August 1977 33

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A PROGRAMMABLE DEVELOPMENT CONTROL SYSTEM (Cont'd)

demultiplexer 64. The input signal to multiplexer 62 is
verified or made compatible with the logic level. A synchro-
nizing clock 66 is employed to time the filtering, multi-
plexing, and demultiplexing of the signals..

During each cycle, transparent electrode 36 is also developed
and a sample of toner particles collected there...