Printhead QY6-0049 (ip4000 series) flow problem

[panos]

I've recently printed another large batch of color documents with full color borderless covers. Everything was going well in the beginning but since yesterday I'm experiencing serious issues with the flow of magenta.

After performing a head cleaning the magenta prints, all dots, but faintly. After a pages with magenta colors, the magenta nozzles clog. This was repeated several times, so I removed the printhead and performed my head cleaning steps with ammonia-based glass cleaner. The problem was solved yesterday and I went through 2000 pages without problems.

Today the problem recurred. Faint magenta, leading to clogs. But it was much more difficult to restore it back to normal even with my cleaning method.

I also tried compressed air, it didn't help.

Finally I repeated my cleaning method, and it worked. Now I am printing and everything looks fine, but I suspect that something has accumulated on the magenta channel inside the printhead. So I will probably have to do Grandad's printhead dissection and have ordered a new printhead...

Any ideas regarding the nature or the solution of the problem are welcome.

 

[Grandad35]

panos,

This could be a clogged head, but it could also be a clogged cart.

When you pulled the magenta cart, was there a pool of ink on top of the pickup? It is possible that your magenta cart has a blocked filter that is causing a high suction pressure, and that the "ink link" is being broken. When you blow into the vent on the magenta cart, does it take more pressure than normal to get the ink to drip?

As a test, place 5-10 drops of rubbing alcohol on the exit port (the filter), give it 10 minutes to dissolve some of the goop, then blow out the alcohol by blowing into the vent port. This should make the cart deliver ink more easily.

 

[ghwellsjr]

I have experienced flow problems with cartridges that have only one sponge in them which is typical of compatibles. That is the reason I use Canon carts exclusively. They have two different sponge materials in them. The lower one is designed to handle ink and the upper one is designed to handle air. Unless air can easily get to the top of the groves that go only half way up the partition separating the two compartments, it will have trouble getting down to the hole at the bottom of the partition under high ink demand. Unless the air bubbles up inside the ink tank to replace the ink that is used, the cartridge will not be able to deliver ink.

A test you can do when the nozzles quit delivering is remove the cartridge and press a tissue or paper towel on the outlet port. You should see ink flowing into the tissue and bubbles coming up from the hole. When you see the bubbles, remove the tissue and the bubbles should immediately stop. If you find that the bubbles don't start until a long time after you apply the tissue and they continue for a long time after you remove the tissue, this means that there will be flow problems under high demand.

I would guess that with thousands of pages of printout, you must be going through several magenta cartridges. Are you finding that this problem only occurs with certain cartridges? Do you have cartridges with both one and two sponges in them?

When you say that "the magenta prints, all dots, but faintly", are you referring to the nozzle check? Are you saying that the two bands of magenta are much lighter than normal or that just one of them is lighter than normal?

 

[panos]

Grandad, sorry for not providing more details. It's definitely not a clogged cart, I tried two different carts and I even exchanged the magenta and cyan carts: the nozzles for cyan did print magenta perfectly while the nozzles for magenta printed faint cyan.

I have stated on my cleaning procedures that I apply very light pressure on the printhead (as it rests on the windex-wet tissue). During this pressure I can see ink flowing on the four pickups but on the magenta pickup.

When you say that "the magenta prints, all dots, but faintly", are you referring to the nozzle check? Are you saying that the two bands of magenta are much lighter than normal or that just one of them is lighter than normal?

Thats right, ghwellsjr. And when that happens I know that after two or three pages intensive on magenta, the magenta nozzles will clog...

See this image:

and

I was getting the faint one 12 hours ago before I finally fixed it. Although to be sure that it's really fixed I'll have to wait for tomorrow morning.

 

[ghwellsjr]

I suggest you read my article:

http://www.nifty-stuff.com/forum/viewtopic.php?id=1504

Pay attention to the pattern of magenta dots. I suggest you print two nozzle checks on photo paper, one while the patterns are normal and one while they are faint. Look at them under magnification. See if there are two droplets placed at every dot position. One of these droplets in each pair comes from the right column of nozzles and one comes from the left column of nozzles for both the dark and light magenta patterns. If there is only one droplet at each position, this would account for why the patterns look lighter than they should. However, if there are two droplets but the droplets are smaller in the faint nozzle check, this would be a different mechanism. A third mechanism would be if there were numerous nozzles not printing at all but randomly scattered. Keep in mind that the nozzle check for the dye inks alternate between two sets of nozzles in a repeating pattern four times across the page so you have to make sure you examine both sets. After we know the mechanism, we can try to come up with a reason and a fix.

 

[mikling]

Bad carts...... leading to heaters slowly getting caked and then appearing as "clogs" to the unitiated. Cleaning helps because you remove the cake on the heaters and then get a strong heater response only to have another buildup due to bad cartridge flow. Classic Canon issue.
Do as is recommended only use Canon carts when refilling and make sure they are in good condition and make sure flow is good or else the cycle begins and masks itself as a "clog".

 

[ghwellsjr]

Mikling, does this "clogging" process you describe cause some nozzles to completely shut down or does it cause most nozzles to deposit less ink?

 

[panos]

It is not a bad cart, see reasoning above. If it were it would have clogged the cyan nozzles too. And the good cyan cart would have worked without problems.

 

[Grandad35]

Panos,

Your problem sounds similar to what I saw when my printhead clogged. As I stated in the original post on cleaning (http://www.nifty-stuff.com/forum/viewtopic.php?id=241), the clog was in the plastic part of the printhead, not in the nozzles themselves. It took numerous vacuum/pressure cycles to dislodge the source of the clog, but the print head has worked perfectly since the cleaning procedure (18 months and counting). Good luck

 

[panos]

As I suspected Grandad. I didn't think it was the nozzles either, but rather the channels. Today it seems that the printhead is working fine, but if it displays another clog it will be opened and cleaned on the inside. In fact, if I had performed the dissection earlier I might have skipped the compressed air step which has possibly damaged a nozzle or two...

Ghwellsjr, instead of printing nozzle checks on expensive photo paper is much better to print a test mode nozzle check. All nozzles were working well no problem there. It is probable that the channels were (hopefully past tense) blocked, ink didn't flow correctly on the nozzles and after a few prints, without any ink the nozzles were simply baking the residue which caused a full blockage.

Thank you all. I'll update the thread if any interesting new developments occur.