Digital BW, The Print

Earlier today, after a successful nozzle check, I tried to print on 
an 1160 w/CIS an 11-sheet (8.5 x 11) run on Epson Archival Matte 
(EAM) of a page which included two small prints and about half a page 
of text. The last five and a half sheets printed very light, and a 
nozzle check print made me think that at the end of the run only a 
few of the black nozzles were printing at all. Judging from an 
examination of the light last half of the run, the stoppage had been 
abrupt as well as nearly complete as far as the black goes.

After a single cleaning, fewer than half of the black nozzles seemed 
to print on the "confirmation" nozzle check. After a second , nearly 
all seemed to print. And after a third, I got the perfect nozzle 
check I am used to seeing the first thing every morning and the last 
thing every evening. (If I haven't printed anything else, I also 
print a purge pattern.)

One at a time, I re-printed the six spoiled sheets after a nozzle 
check before each one. The fourth nozzle check had scattered gaps, 
again only in the black rows in the top of the pattern. After a 
single cleaning, there were no gaps.

This black ink is the black from the new MIS VM Sepia-Neutral (SN) 
quantone inkset. It, however, uses the same black as the other MIS VM 
quadtone inkset, which is not new and which has reportedly been 
relatively clog-free. So I wonder whether I in fact had a clog.

When I installed the new CIS and the Sepia-Neutral inkset on top of 
the OEM inks about a month ago, everything went smoothly. My first 
after-installation nozzle check showed a few defects in the black 
(only). The second nozzle check showed none. Neither did any of 
several purge prints, nor any of several step-test prints, nor any of 
my first print-exchange prints (20 sets of two pages). By now I think 
all of the OEM ink should be gone from the printer.

My experience with the first and only OEM cartridges, which were not 
quite low enough to turn the lights on before they were replaced, was 
similar. I've had to mimic replacing the color cartridge twice since 
installing the CIS (I re-set the black at the same time.) So the 
printer has processed in total roughly the equivalent of one - two 
black cartridges and two - three color cartridges. Half of it OEM ink.

To put it differently, the ink levels in the four-ounce Nalgene 
bottles are near the top of the acrylic stand in which they 
optionally sit. That is, the ink levels are about two and one-eighth 
inches above the surface on which the stand and the printer sit, or 
about one inch below the shoulder of the bottles.

The black ink is slightly lower than the others. At first it seemed a 
lot lower. But I think only because the black cartridge is larger 
than the spaces for C, M, and Y. I didn't think of that until after 
I'd ordered a supplementary bottle of black. So I could fill the 
black bottle up (to just below the shoulder that is). Or I could 
replace it with a freshly filled bottle. But of course the problem, 
if it was an ink problem and any of it remains, is presumably far 
downstream from the bottles.

I'd be glad for any advice or even just any intelligence about how 
this stoppage might have happened.  It seems to me implausible that 
it was a clog, but I also don't see how air could have gotten in the 
system.

Thanks.

Sam McCandless             samcc@...