Appeal No. 95-3759
Application 08/145,118
[w]ith ... respect to the process of the present invention, during the first step
of the blending process ... the toner particles mix with the carrier particles; and are
believed, although it is not intended to be limited by theory, to act in a manner so as
to cause a reduction in the triboelectric charging ability of the carrier surface....
Simultaneously, the charging ability of the toner particle is degraded. However, the
selection of fine toner particles, those for example with an average diameter of from
about 2 to about 10 microns, causes a substantial increase in the surface area of the
toner that is able to act on the carrier surfaces without increasing the mass thereof;
and permits an increase in the probability of the degraded toner particles of becoming
impacted into any crevices or other spaces available on the carrier particle surface.
Accordingly, the degraded toner particles become bound to the carrier surface and do
not adversely impact the initial copy quality.
Similarly, in the second blending sequence a toner composition comprised of
the same components as selected for the first blending operation is selected with the
important exception that the diameter of the toner particles are about 6 to 18, and
preferably 11 microns. Also, the second blending sequence is accomplished for a
sufficient time period to enable the production of a homogeneous mixture of toner
particles and carrier particles; and also to permit the toner particles to acquire charge
by admixing with, and contacting the treated carrier surface... From about 1.25
percent to about 2.50 percent by weight of the toner is added in the second blending
step, however, other amounts may be selected providing there is achieved the
appropriate toner concentration that will preferably provide images with excellent
resolution.
It appears to us from the above teaching from Laing that because it is desirable to employ to increase
the surface area of the toner particles to increase the probability of embedding the toner into the
crevices or other spaces on the carrier surface, there is no reason to remove fine particles of toner or
any other fine particle in the process. Moreover, Laing does not teach or suggest that debris, i.e.
dust, carrier tips and oxide particles (see page 4 of appellant’s specification where the “debris” is
defined), in the final blend would be undesirable. For the foregoing reasons, we find that the
teachings of Laing would not have motivated a person skilled in the art to separate debris and fine
particles from coarse particles as suggested by the examiner. The examiner's suggestion for such a
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