Canon Vizcam 1000, Service Manual

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2. COPYING PROCESS
COPYRIGHT © 2001 CANON INC. CANON CLC1000/1000S/3100 REV.2 MAY 2001 PRINTED IN JAPAN (IMPRIME AU JAPON)
2-12
III. LIMITATIONS
A. Outline
There are many difficulties in making high
quality color prints by an electrophotographic
process, some of which are discussed below. The
Color Laser Copier has many design features to
minimize these difficulties, and they are very
successful.
However, the prints are not of the same
quality as those in high-quality printed material,
such as magazine illustrations and photographs.
Each product has its own advantages and
Iimitations, and users of the copying machine
should be made aware of the capabilities of the
machine.
B. Characteristics
1. OPC
The sensitivity of the OPC used for the
photosensitive drum is subject to the environment
in which the machine is used and changes over
time.
2. Reflectance of Toner
The ideal toners, representing the primary
colors (yellow, magenta, and cyan), should absorb
100 percent of the spectrum of their
complementary colors and reflect 100 percent of
the rest. Such toners, however, are not available at
present.
3. Dry Electrostatic Photography and
Gradation
As shown in Figure 2-301, it is impossible to
reproduce the density of the original document
exactly the same because of the characteristics of
photosensitive material and toner.
The powder toner, further, limits the details of
the image to the diameter of its individual particles.
Figure 2-301
These limitations, however, have been solved
to a point where they will not present appreciable
problems by controlling the image processing by
the scanner unit.
PPC
0.5 1.0
1.5 0
1.5
1.0
0.5
Copy density (Dp)
Photo
Ideal
Document density (Do)