Did I find a cause of print head blockage?

[Tom Hock]

Could I have found the reason for frequent Canon print head clogging? I noticed when I put new ink tanks in my Canon i850 printer there doesn't seem to be much compression of the rubber seal between the ink tank outlet and the print head inlet screen. the ink tanks, when placed into position, are very easy to snap into the lock position with hardly any downward force to compress the seal, and the tanks are easy to rock from side to side, as they are not tightly seated. The original seals may have compressed over time.

If this seal is not tight, might air not get pulled into the print head? This could cause the ink to dry in the head and cause blockage or loss of color consistancy.

I just put my old Canon S750 back into service, and when I get some time (maybe in a month or two) I'll try to place a rubber washer on top, or under, the original rubber seal in my i850 to cause more compression and a better seal. I did a quick test by cutting a small rubber washer from a thin rubber sheet, maybe 1/32 inches thick, and placed it on top of the original seal. The ink tank still snapped into position with very little force, but did seem to be more secure. I'll try 1/16 inch thick rubber next. This has to improve the seal and I can't see any downside to this as long as I don't over do it. After all, it is supposed to be an air tight seal.

I would appreciate any thoughts you may have on this. Maybe someone with more time than I have right now will try this and report the results.

 

[hpnetserver]

I used to have a Canon s820 and used 3rd party ready filled compatible cartridges. I had clogs all the time. For quite a lengthy period of time I kept on looking at things like you did and suspected cartridge seating and questioned if the seal did the job or not as the cause of the clogs. I had many clogs but I managed to unclog them every time. It was a pain in the neck that I had to watch for signs of trouble all the time and frequently had to soak the printhead to fix the clogs. S820 was a slow printer so eventually I gave it away and bought myself a high end ip8500.

I did not want to give up cheap ink supply still but decided to try refill instead of 3rd party ready filled compatible cartridges. I bought a Hobbicolors refill kit off ebay. I don't recall ever had any more clogs. It has been about a year and a half and have gone through two refill kits from Hobbicolors. I have been wodering what makes the difference why Hobbicolors refill kit never ever clog my printhead any more. I first gave the credit to the printer. I believe the Pixma printers with FINE printheads do make a difference. They are not easily clogged. However, I eventually relaized that it is really the ink and the cartridges from Hobbicolors that contributed to the trouble free success of refilling. It is really the sponge in the cartridges and the viscosity of the ink together that make the ink to adequately flow to the printhead from the sponge in the cartridge that makes the difference.

I have carefully examined my virgin cartridges from Hobbicolors. They were not particulary different in the look and feel comparing to all other 3rd party cartridges I have used before. I determined that if there is a difference it is in the sponge used. The sponge is for the purpose of holding the ink in the cartridge and more importantly regulate the ink flow in feeding ink to the printhead. If the ink has a right viscosity then the ink flow will be regulated correctly. The printhead will receive as much ink as it needs at all time regardless you are printing text or photos.

I can see why you are looking at the sealing ring of the ink intake. I have been there. Although done nothing to experiment I eventually convinced myself that's not the problem at all. I am no longer particularly careful in plugging in my Hobbicolors cartridges. I don't worry about the seal on the intake any more. I am so comfortable that I could start up a print job double sided and walk away for a long while. When I return I am just confident that a stack of printed paper with perfect text, graphics and colors would be waiting for me. There is no magic. It is the sponge and ink that make the difference. I don't remember when I did my last cleaning cycle to the printhead of my 8500. It seems never needed one. This is a good indication that the ink is flowing nicely inside the printhead.

So my suggestion for you is to try different brand of virgin cartridges and ink. You can try the three most recommended brands from this forum, MIS, Formulab and Hobbicolors. You may be surprised that it is so easily reachable for a complete solution to the problems you are going through.