Canon multipass c3000 Service Manual (en)

2.8 Optimum Printing Direction Control
To prevent vertical misalignment of the printed characters, etc., when printing data is
printed continuously in the direction of the paper feeding direction, printing is executed with
the carriage moving from only one direction.
However, when the printing in the paper feeding direction is not continuous, since vertical
misalignment is not so noticeable the printing direction is alternated so that printing is also
executed from the opposite carriage direction.  This improves the throughput.
If four or more successive null rasters are detected in the lower (in the direction of paper
ejection) 64 nozzles (24 nozzles with a color BJ cartridge) for the printing data in the printer
buffer during single-pass printing, printing is executed up to the null raster.  From the null
raster onward, the printing is executed from the opposite carriage direction.  From the next
raster onward, the printing is executed from the same carriage direction until the direction
changes again.
2.9 Ink Smear Control
Immediately after the printed sheet is ejected from the printer, the ink dries naturally on the
Paper output tray.  If the next printed sheet is ejected before the ink dries on the preceding
sheet on the Paper output tray, the ink may be smeared when the sheet slides over the
preceding one.  To prevent this, a wait is applied during the printing so that the sheet is
ejected with a delay, giving more time for the ink on the preceding sheet to dry.
When a black BJ cartridge is used (whose printing speed is faster) and high duty printing is
completed, the printer automatically detects the printing position of the high duty printing
and the time elapsed from which the printing starts.
It is not need to execute ink smear control when a color BJ cartridge is used.
Part 2: Printer