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Use of Conductive Polymers on Development Rollers in Monocomponent Electrophotographic Development

IP.com Disclosure Number: IPCOM000107848D
Original Publication Date: 1992-Mar-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 2 page(s) / 97K

Publishing Venue

IBM

Related People

Britto, L: AUTHOR [+4]

Abstract

Disclosed is the use of conducting polymers to enhance the efficiency of the development process in monocomponent electrophotographic development systems and make it less sensitive to relative humidity. The conductive polymer layer is placed under the top layer of the development roller and serves as an improved electrode, establishing the electric fields that control toner development.

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Use of Conductive Polymers on Development Rollers in Monocomponent Electrophotographic Development

       Disclosed is the use of conducting polymers to enhance
the efficiency of the development process in monocomponent
electrophotographic development systems and make it less sensitive to
relative humidity.  The conductive polymer layer is placed under the
top layer of the development roller and serves as an improved
electrode, establishing the electric fields that control toner
development.

      It is well known that the amount of toner developed depends on
the electric field in the development nip in electrophotography.  The
higher the electric field, the more toner develops until all the
toner on the roller moves to the photoreceptor.  Unfortunately,
finding a material which is simultaneously compliant, a requirement
for contact monocomponent development, and also conductive enough to
maximize the electric field has proven to be difficult. Usually this
development roller consists of a metal shaft on which the roller bias
is impressed and is coated with 1/4-inch of nitrile rubber and 40
microns of urethane.  The nitrile rubber provides both the softness
and some conductivity to permit operation of the device.  However,
the conductivity of nitrile rubber is limited.  The low conductivity
of the roller causes several difficulties in the operation of the
development system.  Insufficient conductivity reduces the electric
field in the development zone, reducing the amount of toner that
develops on the photoreceptor per unit voltage.  This requires high
voltages on the photoreceptor to achieve adequate toner development.
In addition, the conductivity of nitrile rubber varies with
temperature and relative humidity.

      This invention increases the electric field in the development
zone by adding a layer of conducting polymer under the top layer of
the development roller.  The development roller for contact
monocomponent development in this invention consists of 5 parts:
      1.   A metal shaft on which the other layers are built and to
which the power supply is attached.
      2.   A rubber material, such as nitrile, to allow for adequate
compression of the roller in contact with the photoreceptor so that a
contact zone occurs over the whole width of the
photoreceptor-development...