A couple of posts ago I mentioned taking on a new painting reproduction job. This is for an existing client, that is, one for whom I've previously done work. For this painter, I proof on matte papers, most often Epson Enhanced Matte. I switch the 7900 to MK ink when using this paper. I use Epson's MK profile, the one installed along with the printer driver. There's a PK profile for this paper too, but not surprisingly it produces clearly inferior results.
On 24 April I swapped PK for MK, ran a nozzle check as usual (no problems found), and made a proof of a large oil painting. The proof printing was fine, although it pointed to additional color correction work I needed to do. I did that, and then printed a narrow test strip from the file as proof #2.
The test strip was awful. It was instantly apparent one or more channels had problems. I ran a nozzle check print, requiring removal of the roll paper so I could feed a sheet of plain bond. I found VLM had completely disappeared, as had nearly all nozzles for LC. These inks had 19% and 26%, respectively, remaining.
These colors are (conveniently) paired in the printhead, so I ran a standard cleaning on that pair. I followed that with another nozzle check print, which showed VLM missing only a tiny corner of the pattern, but LC missing perhaps 40% of its pattern. I was out of time and had to run to a meeting.
Coming back to the printer several hours later, I ran a nozzle check print. It was identical to the previous one. Why would I think it might not be? According to postings on various Web forums, there's a growing consensus that many of the reports of nozzle clogging on the x900 and x890 printers aren't clogged nozzles at all, but may be caused by air being drawn into the ink lines, or other problems upstream from the nozzles themselves. If you're curious about this you'll find a lot to read on the Web. A reported cure is to run a cleaning cycle and then wait 24 hours before checking the nozzles. This has worked for some people. I'm glad they could find the 24 hours to wait.
I couldn't, so I ran another standard cleaning on the VLM/LC pair. This eliminated the few clogged nozzles remaining in the VLM channel, but did not improve LC. I really needed to get on with my work, so I ran a "strong" cleaning of that pair, and then another nozzle check print. Problem resolved. I now had ink being delivered to all nozzles. Perhaps I should have run the strong cleaning in the first place, but there's no way to know in advance whether a standard cleaning will resolve the problem. In my experience, it often does.
I can't complain about clogs. I've had much better luck, if that's what it is, than the people reporting chronic or permanent problems. What's puzzling to me is the sequence: After the PK >> MK swap I ran a 100% clean nozzle check print. I then made a perfect normal print, yet a few minutes later my next print showed ink delivery problems that were fairly stubborn to clear, on two paired channels.
I expect to leave the printer set to use MK for at least a few weeks, barring any unexpected need to print on gloss papers. I'll continue to work as usual, running nozzle checks prior to each day's printing session(s).
--Jay
No comments:
Post a Comment