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Minimizing Hot Roll Fuser Elastomer Wear With Dual Hot Rolls

IP.com Disclosure Number: IPCOM000101804D
Original Publication Date: 1990-Sep-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 3 page(s) / 134K

Publishing Venue

IBM

Related People

Hopping, JM: AUTHOR [+2]

Abstract

Disclosed is a method of reducing elastomer wear on dual hot roll fusers. This would apply when the fusing operation is accomplished on both sides of the paper with one pass through the fuser in an electrophotographic machine that can produce two sided images.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 45% of the total text.

Minimizing Hot Roll Fuser Elastomer Wear With Dual Hot Rolls

       Disclosed is a method of reducing elastomer wear on dual
hot roll fusers.  This would apply when the fusing operation is
accomplished on both sides of the paper with one pass through the
fuser in an electrophotographic machine that can produce two sided
images.

      This article relates to the rolling mechanical interface
between two hot rolls as a sheet of paper is fed through the hot roll
contact nip.  By reducing the sliding of paper against the hot roll
elastomer surface, the rate of wear and the service cost of hot roll
fusing can be greatly reduced.

      Excessive elastomer wear can be markedly reduced by driving
each roll with a dedicated drive motor and drive train using
dissimilar elastomer coating thickness on the hot rolls.

      Each hot roll is comprised of a hollow aluminum core with a
relatively thin elastomer coating on the outside surface.  The roll
is then heated internally with lamps. The roll core is temperature
controlled to keep the external surface of the elastomer within the
acceptable fusing temperature range.  Paper is then driven through
the contact nip of the two hot rolls to fuse the toned image to the
paper.  Each side of the sheet is fused independently of the other
side.  Very little heat is transmitted through the sheet of paper.

      SOLUTION TO EXCESSIVE ELASTOMER WEAR There are two basic causes
of elastomer wear.  The first is large scale slipping between rolls
acting as rigid bodies.  The cause of this is itself composed of two
components.

      With one drive motor, the second roll is driven by contact in
the nip region.  This adds a prevailing shear stress to the contact
zone in addition to the other forces and stresses mentioned below.
The driven roll always slips a fraction of a percent of the drive
roll speed.  In addition to the steady-state roll slip, there is a
dynamic component.  A transient velocity mismatch occurs between the
top and bottom roll when each sheet of paper enters the fuser nip.
The rolls are slowed down by a torque reaction pulse as the sheet of
paper causes the rolls to spread apart to allow the thickness of
paper to enter the nip.  The result in a one drive motor design is
that the rolls react differently to the torque impulse.  This is due
to the inertia of the drive motor effectively adding to the inertia
of the drive roll and causing a dynamic response that is out of phase
with the driven roll.  A velocity and position mismatch then results
between rolls and paper, causing the elastomer to be abraded and worn
away.

      The solution to this first part of the problem is to drive the
fuser with two separate drive motors and drive trains that have the
equivalent drive torque and dynamic response to the paper's leading
edge torque pulse.  This results in no torque transmitted across the
nip between rolls in the steady state.  Also, the velocity is still
pertu...