Chronic problem with one ink channel

I am using Piezography2 / PiezoDN Selenium tone ink in my P400. I print almost every day. I always begin by doing a nozzle check. On nine out of ten days, the nozzle checks are perfect except for one or two small gaps in the cyan channel (the gaps are not always in the same location). A single head cleaning fixes the problem, but all those head cleanings waste ink.

What is the likely cause of the problem and what can I do to fix it?

My P400 almost a year old. The vast majority of problems have been PK and Cyan, the two rightmost locations on the print head. If I get a bad nozzle check in PK (matte black ink), I ignore it, since I’m printing digital negatives. But the matte black ink is usually half gone when I top off my carts, and that gives me a good idea as to how much ink is being wasted by head cleanings.

The other channels never give me problems.

I really don’t know John. You’ve had chronic problems with your P400 and we’ve sold to hundreds of people with this model without issue. what is your room humidity?


Oops, I thought I replied but I guess I didn’t. I run a small humidifier 24x7. RH in the room is as high as 60%. I am able to keep it above 35% in the driest months of the year. RH doesn’t seem to make any difference. I print almost every day, and the first nozzle check always has gaps in PK and Cyan, often quite severe (for example, the patterns could be mostly blank). The other six ink positions NEVER have any gaps. One head cleaning is always enough to remove the gaps in PK and Cyan. But that’s one head cleaning every time I print.


With all due respect, you are fairly new to this inkjet printing thing so I guess you have little for comparison, but what you are describing here as a problem is something that I would wager many if not most experienced printers would consider a very minor inconvenience, for which some would be very happy to trade with you. Let me offer a slightly different perspective on this.

Personally, all of my pigment ink printers, which I have been using since the early 00’s, and which include an Epson Stylus Color 1520 and 3000 (both 4 channel dye printers that I used with early 3rd party pigments), a Stylus Pro 7600, 2 Stylus Pro 3800s, and currently 3 3880s and a 1430, have more often than not needed a head cleaning at the start of every printing session and sometimes much more than that. (There was also a Canon iPF6400, but that’s another story for another time.) This includes OEM inks, ConeColors, Piezography, and 1 or 2 other 3rd party inks that I no longer remember. It is not at all unusual, in fact it is typical.

In your first post you say 9 of 10 days your nozzle checks are perfect except for 1 or 2 missing segments in the C channel. In your second post you say the first nozzle check of the day always has missing segments in C and PK often severe and sometimes the channel is almost completely blank. These two statements of the problem seem to be at odds with each other, but in both cases you say that a single cleaning cycle always clears it up, so it’s a moot point anyhow. Let me repeat that: A single head cleaning always clears it up. That is extraordinarily good. (The old John Prine song Dear Abby just popped into my head.) :wink:

Seriously John - you are in good shape here.

About the use of black ink as an indicator of wasted ink, I think you may be misjudging this. Cleaning cycles use equal amounts of all inks. From the cyanotypes posted on your website, it look to me like you print a mask around your negatives. Even though your cyanotype curve itself uses very little black (mine uses almost none), the mask uses a lot of black ink. Unless you are using rubylith to make your masks, that is where your black is going. It has nothing to do with head cleanings.

You are in good shape here John. I’m serious.


Hi Keith,
Thanks for your reassurance! I do feel lucky that I can always get a good nozzle check after a single head cleaning.

When I refill my carts, the matte black ink (in the PK position on the P400) is half empty. Since digital negatives don’t use matte black, I assume this is an indication of how much ink is being used by head cleanings (as you say, equal amounts of all inks). I’m always surprised at how FEW prints I get from a full set carts. I’d guess it’s 10-15 8.5x11’s.

Photo black ink is in the Yellow position on the P400. I print a black mask for small test prints, but white mask for large prints that I’m going to mat.

I’ve been inkjet printing for a little over 15 years and have used pretty much all of the Epson carts-on-head 13" printers. Perhaps not as much experience as Keith, but a fair bit of it relevant to John’s situation. My view and experience is different. Problems have been rare, and if I’d had problems with the frequency described above I may well have given the game away. When I have had problems, mostly I’ve been able to solve them.

While I prefer the carts-on-head printers for their ease of maintenance, they do require a bit of luck. There’s a fair bit of printer-to-printer variation, and some of them just don’t seem to like refillables. Which is why I wrote my lessons learned post. I may have just been mostly lucky - I know people who certainly haven’t been.

Here are a couple of things that you might try, John.

  1. If you’re having persistent problems, then it’s worth doing for full clean routine so that you have a known good starting point. This is particularly true if you see any cross-channel bleeding in nozzle checks.

  2. If you see nozzle gaps, you could try to clear them by printing purge patterns. If there are just one or two channels with gaps you could purge just those. Not all nozzle gaps are clogs, and on these printers it’s not uncommon for a bit of air to get in, and a purge can be a more effective and economical way to clear it. I usually counsel patience and purge patterns first and head cleans second, with a few exceptions.

  3. One trick that Walker popularised is to place some tape over the vent hole and prick it with a small pin. This effectively reduces the vent hole to a tiny one. It should help increase the back pressure inside the cart. I’m currently successfully using this technique on my R1900, now over 8 years old, to reduce the frequency of problems like yours. It has been remarkably well-behaved from new, but as printers age, problems become more frequent.

Hi Walker,

I run a humidifier 24x7. At this time of year, I am able to maintain RH 60%. In dry months, I’m lucky to get it up to 40%. The humidity doesn’t make a bit of difference. I always have problems with Cyan and PK and I never have problems with the other ink positions. There’s something going on at the right end of the print head.


Dear @john.isner. Sorry for the late reply. Your email reply was stuck in limbo.