Browse Prior Art Database

Active Toner Concentration Compensation

IP.com Disclosure Number: IPCOM000113716D
Original Publication Date: 1994-Sep-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Arnold, RW: AUTHOR [+3]

Abstract

In some dual-component toner electro-photographic printers, toner sensors are used to measure the percentage of toner in the developer mix. If the toner concentration of the developer mix is too high, problems such as high print background and toner dusting occur. The toner sensor is typically used passively to create a signal that will stop toner feeding when the Toner Concentration (T.C.) is too high.

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Active Toner Concentration Compensation

      In some dual-component toner electro-photographic printers,
toner sensors are used to measure the percentage of toner in the
developer mix.  If the toner concentration of the developer mix is
too high, problems such as high print background and toner dusting
occur.  The toner sensor is typically used passively to create a
signal that will stop toner feeding when the Toner Concentration
(T.C.) is too high.

      In a typical toner sensor, the toner concentration voltage
(VTC) varies linearly but in an inverse manner to T.C.  Thus, T.C.max
is the value of toner concentration in % above that which will cause
high background and dusting.  Vmin is the toner sensor voltage
associated with T.C.max.

      In the disclosed scheme Vmin (i.e., T.C.max) is sensed via a
voltage comparator or equivalent component.  When VT.C. dips below
Vmin, a few (N) all black pages are printed to actively drive the
toner concentration to some reasonable level, associated with proper
operation.  The sensor voltage associated with proper operation is
VTEST.

A flow diagram of the logic or code is shown in the Figure.

      The number of black pages, N, to be printed is calculated a
priority and stored in memory.  The number of black pages, N, is
approximately 1/3 of the total number of black pages required to
reduce the toner concentration from T.C.max to a proper level of T.C.