Does Ink Expire?

Thank you all for your comments. I microfiltered one of the Yellow inks into a small bottle (patience is needed) and tried it out in my Epson, one I knew how to flush out if it didn't work. It printed perfect, and didn't clog. The Cyan ink filtered well. The Magenta failed, wouldn't even filter through, so that one went in the tie dye box. Lesson learned, as long as you microfilter the ink, you should be good. The filters are cheap on eBay. Get the non sterile, .22 micron one. My daughter and I have six inkaholic printers between us, so maybe this ink will get used up faster. I sure seem to be filling cartridges every couple of weeks.

Thanks for the update.
So, it sounds like the syringe filter pretty much plugged up completely when you tried to filter the bad magenta. Probably a very good thing. Did you notice any accumulated deposits in the filters with the other inks?
The .22 um filters should stop anything larger than a virus. Maybe overkill unless you're actually trying to sterilize the ink. Did you consider trying the .48 um size?
Thanks again.

My Cone inks purchased in late 2011 are still going strong. I store my inks in the dark and give them gentle mixing from time to time. I am thinking that once the inhibitor has become ....less active shall we say its time to toss the ink out, Filtering out life forms is IMHO only a temp. rescue to troubleshoot berween replacement. I would HATE to kill a print head by having sour ink stand i n the lines or on the pads wiper etc.

There is no reason why ink won’t last for a very long time if stored and used correctly.

Store your inks as you would you food, after all the ink is the food of the printer.

You also cook and eat your food in a very clean environment so the same rules should apply to your inks, and contamination is usually caused by not observing these simple practices.

Wash utensils after use and sterilise them on a regular basics and replace the cap on the ink bottle immediately don’t wait, and discard excess ink never return it back to the original bottle, do this and your troubles will be few..

I got the suggestion to use .22 micron filters off of a site for pros who fix printers. They aren't sterile. It was cheaper than the .48 and I got more of them. Some refillable cartridges have a built in .22. The ink is not sour, still smells new, like alcohol. Like I said, it was stored in a box in a dark closet. As long as the ink works, and doesn't clog the printhead, I'm satisfied.

You asked: Did you notice any accumulated deposits in the filters with the other inks?

It took two filters to strain the ink to fill the small refill bottle. I kept going until they plugged up.

Dye-Based Inks
Dye-based inks differ in chemical composition from
pigmented inks, and, thus have different filtration
requirements. In addition to insoluble dye elements,
gelatinous residues and other contaminants, the poten-
tial presence of bacteriological matter may cause pre-
mature printhead failure. For effective and economical
removal of these contaminants, Pall recommends two-
stage filtration. Prefiltration options include the Profile
II or NEXIS® depth filters while the WATER-FINETM
0.2 µm membrane filter is best for final filtration.

If bacteria could be effectively filtered there would be no need to develop inhibitors and antibacterial chemicals....
There are but two ways to learn, both start with "H"........history or the hard way...

Good luck, really do hope you find a way through so we all get to learn by your hard work, please keep us up to date on your progress

bdazzleddesigns said:

Dye-Based Inks
Dye-based inks differ in chemical composition from
pigmented inks, and, thus have different filtration
requirements. In addition to insoluble dye elements,
gelatinous residues and other contaminants, the poten-
tial presence of bacteriological matter may cause pre-
mature printhead failure. For effective and economical
removal of these contaminants, Pall recommends two-
stage filtration. Prefiltration options include the Profile
II or NEXIS® depth filters while the WATER-FINETM
0.2 µm membrane filter is best for final filtration.

Click to expand...

Thanks for the info.

This snippet is apparently compiled from
http://www.pall.com/main/graphic-arts/ink-jet-ink-formulation-54615.page
The Pall Corporation apparently markets filtration equipment to inkjet ink and inkjet printer oems.

The use of such filtration technology by inkjet ink oems would explain the apparently unlimited shelf life of some oem inks.

3dogs said:

My Cone inks purchased in late 2011 are still going strong. I store my inks in the dark and give them gentle mixing from time to time. I am thinking that once the inhibitor has become ....less active shall we say its time to toss the ink out, Filtering out life forms is IMHO only a temp. rescue to troubleshoot berween replacement. I would HATE to kill a print head by having sour ink stand i n the lines or on the pads wiper etc.

Click to expand...

Cone's marketing info on their pigment ink claims to use "osmosis" (read membrane microfiltration) to sort pigment particle size. This might also remove microbial contaminants. Then again, they might have microfiltered the final product. That might explain the excellent storage life.