Service Manual
5-5
Theory of Operation
5
The print engine prints an image in a raster format, line by horizontal line, dot
by dot. The image to be printed is “described” with the colors yellow, magenta
and cyan. First the yellow raster making up the image is printed, then the
magenta raster is printed, and finally, the cyan raster. (A black raster may also
be printed.) It is the responsibility of the image processor board to communicate
the image data, serially, to the print engine, in this order.
Creating colors
As mentioned earlier, the print engine prints only the colors cyan, magenta and
yellow (and black). However, these colors, called primary colors, can be mixed
together to simulate other colors, called secondary colors. When tiny dots of two
primary colors are intermixed, your eye perceives a third color. That is how the
print engine can use just three basic colors to create multi-colored images. For
example:
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Cyan and yellow intermixed produce green.
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Cyan and magenta intermixed produce blue.
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Yellow and magenta intermixed produce red.
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Mixing yellow, magenta and cyan produces the color black.
It is the responsibility of the image processor board to output, to the print
engine, the CMY-encoded data in the proper sequence to produce the desired
pattern.
