This post documents a case of ink cross-contamination and the circumstances surrounding its occurrence. This problem has been reported elsewhere, and is usually reported when black ink contaminates the yellow cartridge. The first thread below includes a photo of a yellow cart after the contamination, and the second thread is about a similar problem. http://forums.dpreview.com/forums/read.asp?forum=1003&message=13873335 http://forums.dpreview.com/forums/read.asp?forum=1003&message=13931234 The details are: * The printer is an 8 color i9900 using refilled carts from several sources and Formulabs bulk ink. * Since refilling this batch of carts, I have changed 4 PM, 3 PC, 2Y, 1M, and 1K without incident. * The set of carts in the printer when the contamination occurred have been installed for over a week and these carts have not been touched since the last cart change. * Since the last cart change, about 10-15 prints have been made (a few at a time) and the colors have always been OK. * On Sunday evening, I printed about 20 8x10s over a 3 hour period, and the colors were OK on every print. There were no "Low Ink" warnings, even after the last print. * On Monday morning, I printed 2 8x10s and immediately got a "Low Ink" warning on the PM, Black and Yellow (before the printing actually started). Since I normally print until I get an "Ink Out" message, I let it print these 2 pages. * Both prints had horrible flesh tones. * Thinking that one of the "Low Ink" colors was starved for ink, the PM, Black and Yellow carts were replaced. Since the PC cart was almost empty (there was about 1 mm of ink left in the ink chamber), it was also replaced, * A re-print gave the same color problem. * Since the same files were printed on another paper the previous evening and had good color, I assumed that I set up the profiles incorrectly. A re-print after re-setting the profiles gave the same color problem. * A nozzle check showed a good pattern for all inks, but the red appeared to be extra dark. * The "Service test print" showed the same thing - the red was way too dark (I keep a "standard" set of test prints in a box for just this type of problem). * Pulling the Red cart showed the same thing that was shown on the yellow cart in the previous post, but not as severe - There was black contamination in the filter and in a little bit of the sponge. * The red cart is adjacent to the black cart, but there was no evidence of an ink puddle that could migrate directly from the black cart to the red cart. * The red cart was replaced and a cleaning cycle run. * A full 8x10 page of red was printed to purge the red contamination. The top of the page was very dark. It was much better within an inch, but it took over 1/2 of the page for the color to clear to normal. * Subsequent prints were normal. This information agrees with our previous conjecture that the contamination occurs when the printer sits in its home position with the sponges against the heads. There is apparently a vacuum/pressure mismatch in the carts that causes one cart to suck ink back from the nozzles of an adjacent cart (somehow related to an empty cart?). This printer has run very few cleaning cycles in the past week, and the sponges should not have been soaked with ink. In any case, it is a good idea to sop up excess ink from the sponges to minimize the chances that this will occur again. This contamination problem may have something to do with using refilled carts, but the authors of at least the first post used OEM carts. I suspect that it may be related to a print head/cart design flaw that only shows up when a cart is almost empty. I also have to wonder why the black is always involved. The logical answer is that it probably isn't, but that since the problem isn't as noticeable on other colors, we may sometimes suffer with a number of bad prints before the problem corrects itself. If anyone experiences a similar ink cross-contamination problem, please document the circumstances so that we can identify the common factors involved with this problem.