Canon MultiPASS C5000 Service Manual page 205

Part Printer
2.7 Printing Modes
2.7.1 Printing mode
Depending on the cartridge installed, the medium, the printing mode, the resolution, the
print data, etc., the printer varies the carriage movement, bubble jet head driving
frequency, etc., to attain high-quality printing without any bleeding or shifting in the
printout.
When the 720 dpi printing/smoothing feature is used, the carriage feed pitch is set to l/720
inch. Although this slows down the carriage speed, the bubble jet head drive frequency (ink
ejection frequency) is increased so that the overall printing throughput decreases.
During color printing at a single pass, the different colors printed at the same time overlap,
often causing the colors to run. By printing with three passes, color bleeding is less prone
to occur since the color printed immediately before is stable by the time the next color is
printed over it.
When print data is processed internally by the printer, the data is recognized and the
number of ink nozzles to be used by the black ink is changed automatically.
For color printing with Color-HQ2, at 720 dpi, processing is executed in such a way to
prevent the color and black inks from running at their mutual borders and to prevent white
mist.
This processing is executed as follows:
During internal processing by the printer, the borders where the color and black inks meet
are identified. Cyan and black ink are mixed in the printed black portion to suit the state
of the distance and density of the black and color dots.
The printing method for the respective printing modes are listed below.
2.7.2
Photoprint mode
Photoprint mode can be used to obtain high level gradation print quality when using the
Photo BJ cartridge. These cartridges contain a light density ink which achieves B high
level of gradation by printing several times over the same dot.
The printer driver divides the pixel data into a maximum of 4-values (not printed, print 1
dot, print 2 dots and print 3 dots) enabling each pixel to be printed in up to 4 gradations.
The printer therefore makes three passes using a maximum of 400% more ink than usual.
It is therefore necessary to use the exclusive print driver when printing with the Photo BJ
cartridge.
The exclusive printer driver outputs multiple print data to the printer when photoprinting.
If for some reason, a standard color BJ cartridge is installed and used for photoprinting,
everything printed will be doubled in size in the carriage direction.
On the other hand, if color printing is performed with a Photo BJ cartridge, not only will
printed images appear light, the user will be notified of a mis-match as images will be
printed in half their normal size.
2-a