Cleaning Pro-100 printheads

[mikling]

Now that "cheap" Pro-100 printheads can no longer be found it is now becoming necessary for the unfortunate ones who have discovered that Cartridge condition is vital to keeping these printers printing problem free. Method of refilling is important and even with the best of practices, the tank condition will eventually degrade to the point it causes printing and printhead issues. I hope those who have indeed replaced printheads due to "clogging" have kept them as you will discover except for those heavily used in the toughest situations commercially, can many times be recovered with the procedures to follow. Printheads that indicate an electronic fault condition are NOT recoverable with cleaning.

First, let's go over a key point. When the Pro-100 is unused for several weeks or even several months, it is generally problem free from the standpoint of clogs provided two conditions are met.
The FIRST is that when going into a long rest or period of no use, none of the tanks are empty or low and preferably should be refilled to full or near full, depending on the period of intended rest. The tanks will continue to "breathe" daily even when they are unused. This is due to the fact that they are open to the atmosphere and are subject to thermal and atmospheric pressure changes. They will dry out as a result of this, so having full tanks helps. If the tanks completely dry out, then this can lead to a potential head clog.
The SECOND condition is that the printhead parking station operates properly. That the sealing gasket indeed still seals perfectly to prevent the underside of the printhead from "drying" If the seal no longer seals properly then air can leak and slowly the underside of the printhead will dry and ink will dry and cause a clog.
With the above conditions met, clogs from storage are indeed rare.

If the printer does clog from storage, most times it can be fixed by removing the tanks and soaking the underside of the printhead in "Windex" or even dollar store glass cleaner or water modified so that the water does not easily bead but sheets instead. Detergents can do this but choose one free of oils and perfumes which can end up modifying the surface properties of the internals of the printhead making them more hydrophobic or greater tendency to bead. After soaking overnight, rinse the underside as well as the intake ports of the top side until it is mostly clear. Using a kitchen faucet spray hose can also help. Warm water also aids as well.

Dry and reinstall.

Now as stated before the need for the above is low.

The other source of "clogging" generally comes when the printhead is starved of ink while it is printing. This condition originates from the tank not being able to deliver sufficient ink that the printhead requires. This can originate from an "empty" tank, one that is physically devoid of ink from careless management or more often, from continuing to use tanks whose condition has degraded to the point where ink does not want to exit as easy as it normally needs to. In the latter case, printing should immediately cease and a proper working tank should be used.

If printing continues when either of the above happens a printhead can be damaged permanently. If the fault condition lasts a short while and is caught EARLY a proper working tank will fix the situation with no issues. However if extended printing continues before it is caught then more significant problems arise. If it is not too long and a proper tank is used and does not fix the problem then the soak and under the sink flush can resolve it. If it does not then the next stage of resolution is needed.

Before I describe the next stage it is important to identify the nozzles and the patterns.

When you perform a nozzle check, you will notice that above the nozzle check sheet are numbers "1" and "2". This refers to Group 1 as well as Group 2. Group 1 are the colors below 1 and are PC, M,Y,PM. Group 2 are C,BK,LGY and GY. These groupings are significant because each group shares a common seal on the underside of the printhead. So if it is observed that frequent clogging occurs within a certain group when the printer has rested for a while, one needs to check the seal on the printhead. Allied with this grouping are the actual nozzles that fire the ink out.
Looking at the printhead as it would sit in the printer from the front. The Group "1" are the leftmost nozzle group BUT and note this NOT the leftmost tanks on the top. I repeat. Also the sequence of the nozzles do NOT match the arrangement of the tanks of Group "2" as well.

TANK arrangement is as follows. LEFT to RIGHT.
M - PC - Y - BK |||||||||||||| GY - PM - LGY - C

However looking from the front, there are 8 lines of nozzles on the underside. The NOZZLE arrangement from LEFT to RIGHT is as follows
PC - M - Y - PM ||||||||||||| C - BK - LGY - GY

Again pay close attention and observe the order. This will be important when cleaning the nozzles as I will describe in the next post.

 

[turbguy]

I would not use tap water for a "final rinse" of a Canon print head. The unknown amount of dissolved solids will potentially clog the fine nozzle orifices upon drying. They are REALLY small.

You can use tap water for rinsing, followed up with a final rinse with good, distilled water.

 

[mikling]

I should have indicated pat dry and immediately reinstall and test. Any remnants of water will be driven out by the ink in the first prime of cleaning.
To test the effectiveness of various cleaning methods a small experiment was conducted next but the sample printheads need to be laid out first.
I was given printheads that were used in a commercial printing operation essentially uses 48 Pro-100s on a daily basis. Prints are being cranked out continually with a crew managing the refilling, tanks and cleaning etc.
The printheads had been deemed not fixable. The technique of flushing with forced cleaning fluid through the top had failed to restore them. So essentially they were thrown into a bad head box and stored for months and possibly years before I got a hold of some.

These printheads were soaked and rinsed for three weeks initially intended to be days but other things came up and they were put into the backseat. Soaking solution consisted of initially Windex as well as a much stronger solution of LA Awesome cleaner with a dilution ratio of approx 1:20 parts water or less. Each soak was followed with a flush with a water column as well as with a kitchen spray attachment. Essentially this is soaking to the extreme. After one week of this soaking, it had appeared that no colored solution was appearing from any channels. However I got busy and I let the printheads continue to soak and every few days I would refresh the soak solution and continue with the spray flush, After the second week an interesting phenomena occurred, Color had returned to a couple of channels during the flush. This indicated that the deposits had finally started to be dissolved,.....after two weeks! Seeing the results I elected to continue the practice of soaking and flushing to see when it would end with a clear exit of fluid.
The above essentially indicates the amount of time it could take to start loosening up dried and burned dye ink remnants.
As can be discerned, it was pretty much an ad hoc situation depending on time constraints etc. The soaking and rinsing practice was pretty much much more extended than the average person would attempt.

LA Awesome was something I had been using for many years now. It nicely modifies the surface tension of the water to the point where it creeps well into crevices. It also dissolves dye ink very effectively in tests against Windex and other solvents. One needs to use caution when handling it with bare hands at a concentrated level as the detergency will dry out the skin very effectively. So heed handling instructions. It can be found in North America at your local Dollar Tree and is also fantastic at handling kitchen grease. Grease stains on clothes. LA Awesome can get it out. 4-5 years of its use in flushing tanks proves its effectiveness and it is safe with proper handling and reasonable use but use is at your own risk.
It is also far far cheaper than Window Cleaner, Windex etc. and works better in my experience. It will get your tank sponges back to white if you want. It also knock out the Yellow Gello in a flash and is safe for the printhead even in extended soakings. However, one needs to rinse out as much as possible or as suggested use Distilled water to flush and diffuse out the remnants.