Canon i990 suddenly refuses to print black...

[Jovo]

I have been refilling the BCi-6 cartridges for some time with few problems, but suddenly the black is no longer black but a deep brown. I have done a deep clean etc, etc but the first 2-3 inches of an A4 is perfect but after that the black is missing. The printer is only 4 months old and has done around 500 A4s.

Anyone able to help with a diagnosis?

Many thanks.

John

 

[Grandad35]

John,

You don't say what printer you have or which colors it uses, so I'll give a general answer. When printing in photo mode, the "light to middle gray" colors are printed using a blend of C/M/Y (and maybe PM/PC if you have them) rather than with black because the 3 color blend gives a better looking print. As the grays darken, there is a point where the C/M/Y mix turns into a muddy brown and black ink must be added to get the darker grays. It sounds like (as suggested in your title) the black isn't printing properly.

The fact that the first part of the sheet prints correctly before the problem appears indicates that the black cart is probably starving the ink pickup. This is a common problem after a cart has been refilled a number of times. As the filter and sponge become clogged it is harder for the ink pickup to pull ink from the cart. When the printer sits idle for a while, the filter has time to become saturated with ink and can deliver ink for a short while, but eventually it can't keep up with the printer's demand for ink on that print. You can test this by gently blowing into the vent port on the top front of the cart (make cure that it is completely clean before doing this, and do it over a sink while wearing old clothes) to see how hard it is to get ink to drip from the filter on one of the other colors and then repeat the test on the black cart. When the filter/sponge is clogged, it is obviously harder to get ink to flow during this test. Another easy way to test for this problem is to install a new black cart (OEM or 3rd party) to see if this cures the problem.

There are cures for clogged carts(you can search the forum for links if you are interested), but most people just buy new carts when they become clogged.

 

[Jovo]

Thanks for the reply Grandad. The printer is a Canon i990 (it was in the heading to my post) which is a seven colour printer (C,Y,M,PC,PM and R). I tried replacing the black with a new cartridge, but exactly the same result. Do you think it is worth cleaning the head using the toilet/tissue paper trick and windex, posted elsewhere on the form?

It is most frustrating when you waste ink and paper trying to fix the problem, especially when it is being used several times a week. I also have an Epson R210 and use 3rd party inks. So far I have printed around 1200 A4s with it and it has never given me a single problem. Of course it has a great but expensive head cleaning procedure and I can leave it for 3-4 weeks without a hitch.

Cheers.

John

 

[drc023]

The problem is more likely to be with one of the other cartridges. If it was only the black tank being used, the image would go from black to grey and probably with streaks or banding. Since it is going to brown that indicats a composite black made up of CMY. I'd change the cyan tank first followed by yellow then magenta. If your nozzle check comes up ok, there is no need for any cleaning to be done.

 

[Grandad35]

John,

You didn't say how old your printer is, but I assume that it must be almost new since it uses the BCI-7 inks (it's interesting that Canon removed the green ink that they used in the i8500/i9900 - I wonder if they found that it wasn't really necessary after all).

Have you contacted your local Canon service agent? Since the printer is under warranty they will replace the print head for free. I had a similar blockage on my PM ink on a new print head, and the problem turned out to be a blockage in the ink channel that feeds ink from the cart to the print head, not in the print head itself. No amount of soaking or cleaning solutions will fix this type of problem, See http://www.nifty-stuff.com/forum/viewtopic.php?id=241 for details.

I would let Canon look at it.

 

[Jovo]

Thanks for all your advice. It was not the black cartridge, but indeed the photo cyan. I had already replaced it, but it too must have had a problem. I normally check using a print out which shows blocks of the seven colours. Unfortunately it showed all colours working correctly except for black and I was stumped. After downloading a better colour chart, it clearly showed that PC was missing in fact.
John

 

[hpnetserver]

Grandad is probably right about where the blockage is. I had a similar problem on an old i560 on Cyan. Hobbicolors (hobbicolors.com?) is selling a tool that will clear such blockage in the ink passage between the cartridge and the printhead. They sent me one free of charge when I purchased a refill kit from them. I asked them what I could do to fix my i560. They sent me the tool with the kit I bought. You can make the tool yourself I think. It is a small plastic tube to be attached to a syringe. Then you use the syringe to force water into the ink entrance. Well, it wasn't exactly that simple. The small tool had a slightly larger ID (internal diameter) than the ink entrance if I remember it right. You have to press the tool against the padding ring on the ink entrance in order to force water into the entrance. The ID of the tube needs to be larger than the OD of the ink entrance or it may be too tight and has a potential to break the ink entrance pole off. That would mean goodbye to the printhead. After some practices followed by a few round of injection of water the blockage was cleared. The problem never returned. I could not tell how the tool was made. It had one end bigger than the other. One end could fit a syringe exactly and the other end had the right ID bigger than the ink entrance. I am not sure if it was a hand made thing or not. I should still have it somewhere in the house. But I have not used it since I used it the first (and the last) time. My point is Grandad is probably right. The blockage is in the ink passage. It can be fixed.

 

[drc023]

In this case the original poster already replied that the problem was actually a defective photo cyan cartridge. A defective cartridge can make it appear as if the print head is blocked. The device you described can easily be made by using a short piece of vinyl tubing. One end needs to fit snugly to either a syringe or to the ink inlet. The other end can be made to fit by using an additional short length of tubing, but with a larger or smaller diameter so that it functions as a reducer or expander. In using that tool you do need to take care to avoid excessive pressure that could damage the nozzle circuits. From what I've seen, cyan does seem to be the most troublesome color.

 

[hpnetserver]

Oops, I did not read it carefully. Sorry. Regarding the device I agree you can probably make one yourself. The only question would be how to use it. Fear of damaging the printhead is first to overcome. The rest is probably only to take some time to figure out how to make it work by try and error. Bottom line is not apply excessive force to possibly cause damage to anything.