Browse Prior Art Database

Toner Patch Sensing - Detection of Missing Patch

IP.com Disclosure Number: IPCOM000099380D
Original Publication Date: 1990-Jan-01
Included in the Prior Art Database: 2005-Mar-14
Document File: 2 page(s) / 63K

Publishing Venue

IBM

Related People

Bonvallet, JC: AUTHOR [+2]

Abstract

Disclosed is a method of detecting machine failures when toner patch sensing is used to control toner concentration in an electrophotographic machine. The method detects failures that have caused improper toner patch generation.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 53% of the total text.

Toner Patch Sensing - Detection of Missing Patch

       Disclosed is a method of detecting machine failures when
toner patch sensing is used to control toner concentration in an
electrophotographic machine.  The method detects failures that have
caused improper toner patch generation.

      Toner patch sensing is often used to control the toner
concentration of a dual component developer mix in
electrophotographic (EP) machines.  A toner patch is developed onto
the photoconductor surface and the ratio of untoned-to-toned
photoconductor reflectance is compared to a desired control ratio in
order to select a toner replenishment rate for the developer mix.
Normally the toner patch ratio is indicative of the amount of toner
available from the developer unit for toning images.  When the ratio
value is lower than desired, toner replenishment is increased.  When
the ratio value is higher than desired, toner replenishment is
decreased.  Machine failures may cause a large reduction in the toner
patch ratio that improperly indicates the need for toner
replenishment.  This technique detects the failure, suppresses the
toner replenishment, and, if necessary, instigates a machine
shutdown.  These actions are necessary to prevent the secondary
machine problems of excessive toner replenishment and machine
contamination which may cause a costly service call. DETECTING THE
'NO PATCH' CONDITION During normal operation of an EP machine the
toner patch ratio will never drop as...