I have a Pixma MG5320 that stopped printing as well. I got the dreaded B-200 error and tried several strategies. I could temporarily clear the error by opening the cover, turning on the printer, and closing the cover as the carriage moved to the far left. But whatever my next step was (cleaning heads or printing a nozzle check) the error would return. I pulled the print head and cleaned it using water and a small amount of alcohol being careful never to touch the contacts. It took a couple hours of carefully feeding fluid through, but it came out nice. Several hours of air drying it in a warm spot (in dry desert air) later, I re-installed the print head.
The printer behaved nicely as I did a head cleaning cycle but printed absolutely nothing. Serveral more head cleaning cycles (including a deep clean) later, it still went through all the normal printing motions with no errors but the page was perfectly blank. I did notice a curious thing: I had expected the ink levels to drop after all that cleaning but it didn't.
I pulled the cartridges (which I am sure were properly seated, as was the print head) and noticed something. The little inlet nubs where the ink transfers from the cartridge into the print head were still pretty much white, barely colored like the ink. The rubber seals were virtually dry. Through all that, no ink had been flowing! I took the same cartridges and put them in my MG5220 and it printed fine, even using up one of the cartridges eventually.
So what could be wrong? Why won't ink flow? Is there a priming system that is not working? I like this printer and would like to have it work again. I hear people getting frustrated and bailing out to "anything but Canon" but really, this is a nice printer as long as it works. I know this is not a driver issue because even when I disconnect from the computer, restart, and do functions locally, I get the same result.
