Old ink?

[ghwellsjr]

But then it occurred to me that a better test would be to simply put a set of new cartridges in a printer with the tape removed over the inlet into the top of all the cartridges (and with the inlet hole enlarged) and then repeatedly print something until one of the cartridges runs out of ink and then see if there is any difference in the printouts. Isn't that really what we care about?

I finished doing this test and the result is that there is no difference between printouts produced with unmodified "new" cartridges and modified "new" cartridges as described in the above quote. I put "new" in quotes because the cartridges are many years old but still in their wrappers.

I decided to print both of the images in the previous post on Staples photo supreme matte paper. I printed one of the color bars and then ten of the bird and more or less repeated until I ran out of ink. I was able to go through about eight sets. I did this on a Canon i860 which uses the same print head as the iP4000, the MP780 and several other printers. When I got done, there was no noticeable drop in the photo black ink in the reservoir. All three colors had empty reservoirs although the magenta had just emptied. The yellow and cyan both reported the red out-of-ink alert at the same time and the yellow quit printing in a couple prints done after the test.

I had a problem with the i860 being able to automatically feed the thick matte paper and I ended up having to manually help each new page. After doing three sets and not seeing any drop in the ink levels on the status window and since it was late at night, I decided to put in plain paper and print as many pages as possible. However, I continued to tell the printer it was matte photo paper. After 40 pages, the printer said that the yellow and cyan were out of ink. However, I decided to put back in the matte paper and continue printing. I was able to print one more set. By the way, I always print the color bars on matte paper.

Since I am color blind (weakness of seeing red), I showed the printouts to my wife. She said there was a slight difference in the first printouts compared with successive printouts. They tended to get darker. I focused on just the six color bar printouts and even I can see a slight but noticeable darkening along the left sides of the color bars and in some color bars overall. This is something you would never notice unless you were comparing printouts side by side.

So this made me wonder if this darkening was a result of the modified open air path on the top of the cartridge or whether unmodified cartridges would produce the same result. The cartridges I used are many years old. I decided to repeat the test with unmodified cartridges. I first cleaned the ink out the print head and put in a new set of color cartridges. Since the black is hardly used at all, I simply put tape over the hole I enlarged and continued to use the same photo black cartridge.

I went through two sets plus an extra color bar at the end resulting in three color bar printouts. They showed the same darkening pattern as the modified tests. There is no difference between the first color bar printouts from each test or the second or the third. I decided not to continue the unmodified test.

But this raises a question whether a fresh set of newly purchased cartridges would produce the same slight darkening effects as the cartridges that I used which are many years old. After I collect enough Staples rewards in a couple months, I will buy a new set of color cartridges and repeat the test to settle this question. I may also do it with with some refilled cartridges.

But this issue has no bearing on the result of the test of whether the serpentine air path is used to regulate the ink flow between the reservoir and the sponge side of the cartridge or anywhere else in the ink or air flow paths. I continue to believe that the serpentine air path with its three wells are there to reduce the air exchange caused by daily fluctuations in the ambient air pressure.

 

[fotofreek]

Interesting that you expanded the air intake over the sponge area of a new OEM cart. I had only increased the size of the hole on non-OEM carts that had a smaller hole than others and appeared to have a "breathing" problem. From your experiment it appears that even enlarging the OEM air vent works the same as leaving the original hole size.

As far as the feed issue with the Staples double sided matte paper is concerned, my i960 needed a little push for nearly every sheet to feed. The ip5000, however would print several sheets unattended. Made it much easier to do my large run of end-of-year greeting cards and other large print runs with this paper.