Browse Prior Art Database

COPIER (DEVELOPMENT CURRENT SENSING)

IP.com Disclosure Number: IPCOM000023573D
Original Publication Date: 1978-Apr-30
Included in the Prior Art Database: 2004-Mar-31
Document File: 2 page(s) / 327K

Publishing Venue

Xerox Disclosure Journal

Abstract

In some forms of xerographic development, a developer current flows between the applicator and photoreceptor during develop-ment of the image on the photoreceptor, A current controlling circuit is provided for automatically adjusting and main-taming such a current.

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 72% of the total text.

Page 1 of 2

XEROX DISCLOSURE JOURNAL

COPIER (DEVELOPMENT CURRENT
SENSING)

Peter Frederick Clark

405 ~__.

VOLTS 8

Proposed Classification
U.S. Cl. 118/653
mt. Cl. G03g 15/08

APPLlCATO~

In some forms of xerographic development, a developer current
flows between the applicator and photoreceptor during develop-~
ment of the image on the photoreceptor, A current controlling
circuit is provided for automatically adjusting and main~
taming such a current.

In operation of the circuit, the switch (8) is initially
closed so that the capacitor (19) is fully charged. The
output of the comparator (1) holds the transistor (14) ON.
Current flowing through the zener diode (12) and the transis~
tor (13) ensures that the transistor (10) is ON, The currents
flowing through the transistor (10) and (14) discharge tt'ie
capacitor (19) and the voltage of the busbar (3) falls so
reducing the bias on the applicator roll of the copier which
is connected to terminal (A)

Volume 3 Number 2 March/April 1978 97

[This page contains 1 picture or other non-text object]

Page 2 of 2

COPIER (DEVELOPMENT CURRENT SENSING) (Cont~d)

Developer current begins to flow through the resistor (20) and
develops a voltage across the resistor (2) . The desired
developer current for mid~grey is previously calibrated for
the development system of the copier and corresponds to a
voltage difference set on the potentiometer (4) . The capac~
itor continues to discharge and the developer current con~
tinues to increase until the input voltages at the c...