Brother DCP-9010CN, Service Manual

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2-22
Confidential
3.5 Principle of Color Overlapping
The human eye distinguishes one color from others by receiving light’s three primary colors
(Red, Green, Blue). When monochrome lights are received, each color can be sensed.
However, when two-color lights, red (R) and green (G), are received, they are recognized as
“yellow”; when three-color lights, red (R), green (G) and blue (B), are received, they are
recognized as “white”. The fineness of coloration is perceived according to the nature of light.
Fig. 2-18
For printed colors, the human eye can perceive them as various colors by distinguishing each
color light reflected off the surface of a sheet of paper.
Theoretically, if cyan, magenta and yellow are mixed, all the colors are not reflected and black
can be shown. However, a black mix is difficult to produce, and black is shown using
blackcolor paint for practical purposes. Using such a principle, color-absorbing paints are
mixed to allow many colors to be shown on the surface of a sheet of paper.
(1) Green+Blue
“Cyan” absorbs red (R) light only
among the three-color lights and
reflects green (G) and blue (B) lights,
and consequently the light is identified
as “Cyan.”
(2) Red+Blue
“Magenta” absorbs green (G) light only
among the three-color lights and
reflects red (R) and blue (B) lights, and
consequently the light is identified as
“Magenta.”
(3) Blue
If cyan and magenta are mixed, cyan
absorbs red (R) light and magenta
absorbs green (G) light, and only blue
(B) light is reflected. The light is
identified as “blue.”
Fig. 2-19
Red
Green
Blue
White
Yellow
Cyan
Magenta
Cyan toner
B G
G
R
B
Absorbed Reflected Reflected
Magenta toner
B G R
R
B
Absorbed Reflected Reflected
Cyan toner + Magenta toner
B G R
B
Absorbed Absorbed Reflected