Refilling cartridges where pigments have settled

[limprimerie]

Hi all,

We’ve been experiencing what seems to be a pigment settling issue with our Pro inks. We have been printing consistently (many times per week), but did not agitate our cartridges from the printer. Now we see a big hue (Cool tones are much cooler!) and overall density change in our prints, so our conclusion was that it must be due to pigment settling down.
We are soon going to refill the cartridges with new ink from new bottles we just ordered.

Should we discard the old ink remaining in the cartridges before adding new ink? Will old ‘settled’ ink contaminate the rest if mixed with new ink? Is it possible to dilute it, for example keep 10% of old ink and fill with 90% new ink, and do that everytime we refill cartridges to avoid throwing away what we have left?

[walkerblackwell]

I’ll follow up w/ you on PM.

An agitation of the cartridge + mix-in with new ink should be ok but it’s dependent on various details.

Will email in morning when back at work.

-Walker

[Brian_S]

The answers will be of general interest.

[walkerblackwell]

Short answer:

At Cone Editions Press we do a monday morning ritual for all x9xx wide format printers. We do a gentle shake of each cartridge. This ensures pigment remains consistent as it goes into the ink lines/dampers/head. On the x880s we did this by shaking the wire rack they were on.

If you don’t have much left in the carts, it could be worth it to empty and replace with fresh ink. If you have a LOT of ink left, mix with fresh ink, keep carts agitated, run some power cleanings and do a linearization.

Keep in mind that you will want to do a shake of the carts before a print-session if the printer has not been run for more than a week. This is a recommended procedure for any pigment ink (of any brand) and is even recommended in graphic form on the Epson WF carts (hand shaking).

Canon printers have ink agitators for each ink channel. Epson sadly does not.

best,
Walker

[Brian_S]

Thanks. Part of what I was interested in was how long limprimerie’s carts may have sat unagitated, and by implication how long it took for a significant amount of sedimentation to occur in Pro inks.

In K7 inks (but different printer type) I get measurable curve drift in four weeks. In this post last year you indicated that Pro inks are less inclined to sediment, and so the question posed by limprimerie’s experience is how long can you leave Pro?

[walkerblackwell]

We accidentally did not agitate for several months and were fine. But this was fresh ink. As ink ages past the 1yr mark it requires some more agitation of carts. So better safe than sorry, agitate carts either every week or before your print-session whatever comes first.

-Walker

[limprimerie]

Thanks for the info Walker. We actually printed every week, at least 3-4 days a week, since we installed our Pro inks. The printer never sat without printing for longer than a few days.

If I understand correctly, printing regularly isn’t enough with Pro inks and the 9900 - shaking cartridges every week / 2 weeks is necessary in addition to the printer running many days per week?

In our case, the color shift occurred after we sent our first few large jobs (30 x 40 and 40 x 60 inches prints). Could that be related? Before that, we’d been printing smaller - between 8 x 10 and 20 x 24.

We have about 50% of ink left in our carts right now. I would rather not throw it away so I was considering just keeping about 10% of old ink and pour 90% fresh ink, and just use it progressively like that, as we refill over time - and obviously agitate carts + run a cleaning before printing.

Interesting to know that after 1 year past its fabrication date, inks tend to need more agitation.
Looking at our ink bottles, the older ones seem to date back to March '17 - including the Cool - Dark tone, which is what mostly shifted in our prints. and PK dates back to January '17.

From now on, we’ll definitely agitate each cartridge once a week to prevent that from happening again. Do you recommend anything else?

Thanks Walker!

[walkerblackwell]

@limprimerie

If I understand correctly, printing regularly isn’t enough with Pro inks and the 9900 - shaking cartridges every week / 2 weeks is necessary in addition to the printer running many days per week?

Yes. On wide format printers. It’s important to shake carts. They are stationary.

@limprimerie

We have about 50% of ink left in our carts right now. I would rather not throw it away so I was considering just keeping about 10% of old ink and pour 90% fresh ink, and just use it progressively like that, as we refill over time - and obviously agitate carts + run a cleaning before printing.

That sounds right.

@limprimerie

From now on, we’ll definitely agitate each cartridge once a week to prevent that from happening again. Do you recommend anything else?

If you are agitating your carts regularly and printing regularly you will be fine.

best,
Walker

[limprimerie]

Great, thank you, I’ll do that.

Is there a maximum shelf life while inks are in their bottles, before we refill cartridges?
Or will I avoid pigment sedimentation as long as I shake bottles regularly, and before refilling my carts?

[walkerblackwell]

@limprimerie

Is there a maximum shelf life while inks are in their bottles, before we refill cartridges?

No really. Just shake before fill.

@limprimerie

Or will I avoid pigment sedimentation as long as I shake bottles regularly, and before refilling my carts?

Yes.