Canon i9900 Banding

[thunnus]

My Canon i9900 is acting up. Had to print a batch of newsletters for my church and it started banding about 1/2 way through 300 pages (double-sided). I normally use Hobbicolor carts and MIS inks. I've tried swapping to OEM carts and have gotten the same results. I tried cleaning the printhead (Panos' Windex on tissue method) and no change. Yesterday I tried a long term (approx. 20 hour) soak in a thin layer of Windex and dropping a few drops of Windex on the pickups. No change. Here is my latest nozzle check print (contrast bumped down a couple notches)...

Here is a sample photo print (Canon OEM ink on Kirkland Photo Paper)...

Performance on plain paper is much worse (Canon OEM ink on plain paper)...

Do I need a new printhead? I don't mind shelling out the $100 or so if I know it will buy me a few more years with this printer. This forum has been very helpful to me in the past and I thank everyone here in advance for all of the knowledge that you guys share. It is invaluable.

Sincerely,
John

 

[mikling]

I have run into this on an i950 and i9900 but this was quickly cleared up.

I suspect you initially had an ink supply issue with your cartridge/ink combination during your printing run didn't pick up on this immediately and then got some scorched inks on your heaters in your print head. The fact that you noticed is good news as that would decrease the likelihood that you did terminal damage.

Here's what to do.
Remove your cartridges, and then remove your printhead.
Take the printhead to a kitchen faucet/tap and get some very warm to hot water flowing in a solid column. Let this column of water fall onto the printhead nozzle plates. Vary the angles of contact of the water column.
Keep doing this for at least three minutes. Turn the printhead over and look at the ink inlet ports. You'll see ink coming out. Wash it off and resume the flushing of the nozzles plates until you get no more colors coming out of the ink inlet ports on the other side.

After doing this soak the printhead in very warm water for at least an hour or preferably overnight. Time is your friend here.

Next, flush the heads again and see if there are any more colors coming from the inlet ports. Continue doing this until no more colors appear. You can take a moistened paper towel and dab the head. If there is still color on the tissue, soak again and flush until there is no more color.

Dry the electrical contact plates and see if you blow out the moisture under the contact pad.

Replace, install some new proven to be good cartridges. Do a head cleaning and nozzle check. Chances are, you're good. If not, let it sit overnight, and another nozzle check. If you're not good, I'll tend to think a damaged head at that point.

I always recommend flushing cartridges before they cause the problem you've run into AND at the same time take the opportunity to flush the heads out. With these two steps you're assured superb performance over a very very long time.

Also if you've purchased large bottles of ink be careful of the shift in ink physical characteristics as the small remaining amounts of ink towards the end dry out in the large bottles. These could and will cause ink supply issues if they've dried out and thickened up sufficiently. It's tempting to go for larger bottles for the economy but proper handling is needed.

 

[ghwellsjr]

Excellent advice, mikling, I would just add that it is VERY important that the electrical parts that are not visible be completely dry. Blowing with canned air is good, but I would suggest waiting a day before installing the print head back in the printer, just to be on the safe side.

 

[hpnetserver]

Your nozzle check print shows BK, C, M and Y all have banding. This is very unusual to get all 4 main colors to clog at the same time. If you were not careful you could get one color to clog. You have to be ignorant to allow all 4 to clog. When you print 300 pages (actually 600) double sided you really need to be very careful watching the printer closely. If you stop printing the moment any sign of problem began to show up you could have avoided completely the trouble having to unclog the print head. The printer probably kept going for a while after the problem began. The heaters in the nozzles probably had fried the ink into solid particles when ink wasn't fed sufficiently. The ink solid particles are clogging the nozzles now.

Soaking print head for too long can be harmful. You should make your own cleaning cartridges filled with Windex fluid. Plug in the cleaning cartridges and go through a few deep cleaning to prime the nozzles with Windex fluid. Let the printer sit with the cleaning cartridges for a few days. This is a safer unclogging method and can be effective too.

 

[mikling]

hpnetserver what components of water are unsafe for the printhead?

If anything Windex with alcohol and ammonia present more risks than water on a prolonged basis. If you are correct, then long term exposure of ink within the printhead itself will damage the printhead internals since the major component of dyebase ink is water. The nozzle plates, adhesives that seal ink chambers to nozzle plates, ceramic, silicone gaskets and sealant and stainless steel ink inlet covers are not damaged by water.

Can you elaborate and indicate what components will be damaged?

 

[mikling]

ghwellsjr, keeping the printhead out for a day to dry can present another problem. As the water dries, air enters the ink nozzle chambers and also through the ink inlet ports. If air is trapped in there when the cartridges are installed, they can be troublesome to remove at times and if not completely cleared, will reintroduce banding. It is thus possibly better to blow behind the contact plate dry as you recommended and reinstall the printhead and cartridges right afterwards. This will minimize the possibility of introducing air into the printhead chambers.

The electrical components behind the contact plate are water resistant. The only problem is that if there is humidity present it could create some high resistance and false capacitance issues that could fool the printer into thinking it has a defective head. This disappears as soon as it dries further. If one only soaks to cover the nozzle plate and not reach the electrical contact and flushes so that a minimum of water flows over the contact board this possibility is removed.

Of course one could also go to the trouble of sealing off the edges of the contact board with masking tape before flushing and never worry about moisture behind there!

 

[hpnetserver]

Mikling, there have been reports by people who soaked their print heads for too long which turned out to be fatal when they reinstalled the print heads to find blinking LEDs on their printer. I have seen an i820d failing from lengthy soaking of print head. I have seen similar reports from others on the internet of other printers as well.

Canon print head is really an electric-mechanical composite device. Although sealed but lengthy soaking could lead to unexpected fatal consequence. The purpose for soaking is to dissolve ink solid accumulated in the nozzles and tiny ink passages inside the print head. Using cleaning cartridges does the same thing but avoids exposing other part (mainly electronics, such as boging wires connecting the print head ship to the cable) from getting damaged from water and minerals, such as salts, Calcium, etc from causing damage. Soaking for a few minutes is generally believed to be safe but for hours or even days you should warn your customers the potential risk to their print heads.

I have seen a distaster between water and semiconductor which caused a high tech company to recall hundreds of computers selling 10 million dollars each. The consequence turned out to be fatal to the company. It collapsed and was sold to another company. Within a few years both company was shut down and laid off all employees. The disaster is know as silver migration. Some moisture trapped underneath some VLSI chips causing the molecule of silver from the silver coating on electronic signal wiring to migrate across between wires and shorted the circuit.

You may be able to get away by luck for soaking your print head. But you should warn people about the risk that can be fatal to the print head.

 

[hpnetserver]

"keeping the printhead out for a day to dry can present another problem. As the water dries, air enters the ink nozzle chambers and also through the ink inlet ports. If air is trapped in there when the cartridges are installed, they can be troublesome to remove at times"

Mikling, air always get into nozzles and anywhere between the ink intake and the openings at the bottom of the print head. When an ink bubble is formed it is a thin layer of ink ball with air inside. I can agree that it is probably not a great idea to allow a print head to become totally dry but not for the reason it will trap air inside the print head. What is exactly trapping the air inside a print head? Unless both ends of a passage are plugged up air is free to come and go. Actually it is moisture that may be trapping air inside the print head. There is nothing to trap air if a print head is completely dry.

Remember, printer's cleaning cycles are for priming the nozzles with ink and also for the purposes of sucking air out of the print head. That's the unwanted excessive amount of air. There is always air in a print head. As long as there is sufficient amount of ink in there presence of air is not a problem in there.

 

[hpnetserver]

"The only problem is that if there is humidity present it could create some high resistance and false capacitance issues that could fool the printer into thinking it has a defective head. This disappears as soon as it dries further."

This statement is false. Presence of water or humidity is harmful to electronic circuits always, regardless it is the PCB on the Canon print head or the MB of your computer. There is always tiny amount of salts in water. It may come from the PCB or its in the tap water if you soak with tap water. The water or humidity may become acidic or base which can cause metal of silver, gold or copper to oxidize. The electronic wirings may become open or short. Semiconductor compoents may be attacked and become damaged. The damage may be irreversible.

Short soaking of print head with distilled water for a few minutes is safe and is all you need. If the clog is tough to crack down using cleaning cartridges.

 

[Grandad35]

My i9900 has an IC with open leads on the back of the print head's PC board (http://www.nifty-stuff.com/forum/viewtopic.php?id=241). I would recommend keeping this area dry, if possible. Tap water contains salts which are conductive and which can be left behind when the water evaporates. For this reason, if you get the back of the PC board wet, I recommend flushing the area with either distilled water or rubbing alcohol, blowing it out as quickly as possible, and letting the print head dry completely before installing it back into the printer.

If you want to soak a print head, I like the solution previously posted in this forum (I don't remember the title or who posted it) of setting the nozzles on a folded paper towel that has been soaked with your cleaning solution of choice. Pressing down repeatedly on the print head causes the cleaning solution to be "pumped" into the nozzles and channels. You should be able to see the cleaning solution push up slightly from the ink pickup when the head is pressed down. My spare print head is stored in this manner in a sealed container, using print head cleaning solution as the liquid.