Banding on high speed, not on hi quality

How did you clean the head bottom. It often has a LOT of dried ink on
it, and a partial cleaning may not be adequate to remove all the dry ink
which can cause nozzle deflection.

Also, do an alignment, sometimes stuff that shows up in bi-directional
head movement that doesn't in uni is due to alignment being out.

Make sure the head wiper is clean (next to the cleaning station). Be
gentle when cleaning the underside of the head to avoid misaligning the
heads. Make sure you use a lint free paper towel and no residue from it
has been left behind.

Last step, if nothing else works, you may need to run some cleaning
cartridges, as you may have a partial internal clog in one of more
nozzle. This is simple to do with the SC900 because it is unchipped and
uses the simple to refill cartridges.

Art


DaveC wrote:

Epson SC900. I get vertical banding (bands that run horizontal) on the black
and yellow inks when printing high speed (bidirectional), but not when
printing high-quality (unidirectional).

The yellow has a little black that makes up the bands, while the black simply
varies in density.

Why would this be? I've cleaned the bottom of the head, the head "park" pad,
and run cleaning fluid through the head. None seems to help.

Ideas?

Thanks,

Sometimes, nozzles are deflected slightly. If you look at the nozzle
check very closely, you may see the steps are uneven or out of sequence
in location. Sometimes the nozzle is clogged enough that the ink is
delayed in getting out.

Sometimes there is just enough obstruction that the amount of ink
getting out is not the full amount, so the ink line is thinner or
mispositioned.

Very occasionally, paper transport problems can lead to banding (the
gears may be worn, the stepper motor not driving the gears or other
parts correctly. Paper slippage due to glazed platen or other parts can
also occur.

Most often the problem is the heads, however.


Art

DaveC wrote:



A Question: if the nozzle test print shows all nozzles firing, then doesn't
this prove that the nozzles are healthy and aren't clogged? How can cleaning
them out more improve the banding problem?

Thanks,