PIXMA MP780 purge unit

[stuber]

I am in the process of repairing an MP780, and I think I need to clean the purge unit. My problem is that I can't find any directions as to how to do it. I don't want to cause any more harm than necessary. Anybody out there know the procedure to clean the purge unit on this machine?
Thanks

 

[Trigger 37]

Stuber,... boy are you asking for it. The purge unit is at the absolute bottom of everything. I have the MP730 and have taken it apart down to the bare "Plastic". This is one of the most complex disassembly tasks that I have done. The difference in the MP 780 and my MP730 is yours has a new streamlined design and appearance. It is more compact, has a cassette tray at the bottom, and the covers come off different. It also has the BCI-3e black, BCI-6 CMY, & blk ink carts.

The question is, how do you know it is the purge unit, what symptoms are you getting? There is another simple test to see if your purge unit is clogged. Open the cover to get at the ink tanks and when the carriage comes to the center pull the power plug on the printer, then move the printhead more to the left. Have a syringe ready or an eye dropper with some Windex-Original with Amomnia D. Use a flash light to see into the right side of the open area where you can reach the ink Caps. These are the small rectangular suction units where the printhead sets all the way to the right. When the carriage is Parked, these ink caps come up and cover the inkjet nozzles. There is one on the left for the black and one on the right for the color. Add several drops of Windex to each cap until they appear flooded. I am talking drops because they don't hold that much. The windex should begin to absorb through the Caps and down through the purge tubes to the waste ink pads. If it all goes in, add a couple of more drops. Now plug the power back in and turn the printer on. The carriage will move through a couple of cycles and you should hear the purge unit doing a couple of cycles. One is for the black ink and the other one is for all the other colors. Close the cover and let the head do a parking cycle. This takes 55 seconds. Once it is parked turn the printer off and then on again with the power button. The power on cycle will force the printer to do a purge cycle just to test the purge unit. This is all part of the Canon power on Diagnostic routine. When it is finished and comes ready, raise the cover again and use your light to see if all the Windex is gone from the ink Caps. If you can reach the ink caps, add some more windex and repeat the cycle by closing the cover and cycling the power. Keep doing this if the ink Caps appear to be getting cleaner.

If this is not working, or there is some other problem with the Purge unit you should be getting some flashing lights telling you about the error. I had one last week that was giving me two orange flashes, which can be many things like the printhead, the carriage, the timing strip, or the purge unit. Mine was that a spring had come out of the purge unit and the cams inside would not cycle and physically raise the white locking foot that holds the carriage locked after 55 sec's , or whenever the power is turned off. Of course I had to totally disassemble the printer down to the bottom where I found the spring. The housing on the purge unit was cracked, and I suspect that someone tried to "Force" the carriage to move when it was locked. This cracked the housing, and the spring "Popped Out" and after that it would still cycle but it would not lock. The sensors in the Purge unit detected something was wrong, flagged this to the Canon Power on Test cycle,.. and that set up the orange flashes. I used epoxy on the housing, replaced the spring, flushed and cleaned the Purge unit and the Caps, cleaned and dried the Waste Ink Pads, put it all back together and now I have an almost new printer.

By the way, I'm writing an Instruction manual, with photographs and detailed instructions on how to do these things to many different models of Canon printers. I should have this manual, along with the Canon Service Manuals and Canon Parts catalog for each machine in a couple of weeks Then it will be for sale on eBay. These machines are not that easy to fix. If you do something wrong, you can really break something you won't know how to fix or where the problem is located. All the Canon machines have some little trick to getting the covers off and if you don't know the trick, either you won't get them off or you will break a cover doing it. If your problem is really with the purge unit, then my test above should tell you. It could also break up any clog that might be there,... but you may have to repeat the process several times.

 

[stuber]

Tigger 37... First of all thanks for the info. The symptons I am getting are: Printer appears to work completely, that is no errors or hick-ups of any kind. When I perform the nozzle test- the top section which is for the BCI-3e large black does not print. all the other lines look fine. It is my understanding that this top section is for the BCI-3e black. If I try to do a copy in black I get a blank sheet of paper. If I try copy in color it works. If I try to scan text only it works but is extremely light. Printing from application (word) i get a very light copy.

If I am going down the wrong path based on these symptons please let me know

 

[jflan]

Great info from Trigger 37, but I think from reading your second post you are going down the wrong path for this problem.

Your description in post #3 reads like a clogged black printhead.
If you have tried the typical printhead cleaning regimen in your printer's utility I would next try a "Cleaning Cartridge" rather than Deep Cleaning.
I don't like using Deep Cleaning because it uses lots of ink and speeds the filling of the Waste Ink Reservoir.
My success also, has been marginal with it.

I recently had a iP1500 with the same problem and a G&G cleaning cartridge (black) did the trick.
I found the cleaning cartridge at PrintPal.
Using a printer prime page is very helpful when utilizing a cleaning cartridge.
You can create your own in MS Paint or Google one up.
In this case you would be printing a large black block pattern. This helps to get a good volume of cleaning fluid flowing for those bad clogs.

I would use Greyscale during this process to make sure that my efforts were concentrated on the black tank and head.

Edit:
If you can't wait for shipping, I have made up my own cleaning cartridges with one part Isopropyl Alcohol (90+%) and two parts Windex Original w/AmmoniaD
Thanks to Art Entlich for that.

 

[stuber]

Jflan... Thanks for the info. This is a used machine. It was given to me and it had a "PUT IN CARTRIDGE" error. After I put in a new printhead the error went away. By putting in a new printhead would it no longer be an issue of a clogged printhead? Or are you referring to something other than the actual printhead?

I am not familiar with the cleaning cartridge. Do you have them available, and if so how do I get one?

 

[jflan]

Jflan... Thanks for the info. This is a used machine. It was given to me and it had a "PUT IN CARTRIDGE" error.

OK, I'm going to read between the lines here...
If there was no cartridge (black) in the machine when you rec'd it, then it would be very likely that the inlet, channels and printhead would be clogged.
An inkjet printer should be without a cartridge only for as long as it takes to replace it.
Read...seconds.

After I put in a new printhead the error went away. By putting in a new printhead would it no longer be an issue of a clogged printhead.
Or are you referring to something other than the actual printhead.

I'm not sure if you mean printhead or cartridge.
I didn't know that you replaced the printhead and obviously, if you did, there should be no issue with a new printhead.
I do have a suspicion that you meant cartridge.

I am not familiar with the cleaning cartridge. Do you have them available, and if so how do I get one.

See my first post, there is a vendor listed. Search on your cartridge's actual part number.
The cleaning cartridge is of course specific to the precise ink cartridge that it temporarily replaces.

 

[stuber]

jflan...When I got the printer it had a complete set of cartridges in it. After I replaced the printhead i put the original cartridges back in. I got no 3e printed at the top of the nozzle check page. I replaced the BCI-3e cartridge with a brand new one and the results were the same.

 

[jflan]

OK, I think I'm following now, although I'm not sure why the printhead replacement so soon in the troubleshooting session.
Assuming no more error codes.

Anyway, you have a new printhead and a new BCI-3 cartridge.
If the printhead and cartridges are healthy and primed, the printhead will blot.

Quarter a paper towel and moisten it with water. Now take the printhead assembly (with cartridges still installed) and VERY gently try to blot with it.
You should see a distinct, repeatable pattern of all colors.
Of course we are interested in the black.

If the black doesn't blot, then it is not primed. It's possible that an electrical fault is causing this.
These printheads often will have a protective glycol substance on them. Let's hope that it simply hasn't been flushed yet.

If this is the case, I'll link you to a prime page, grab the black primer and after a head cleaning, try it.
http://www.ink-refills-ink.com/InfoPages/1primepage.htm

 

[stuber]

jflan... Thanks for the info about the priming. I did download the files and have tried to print it several times. No luck. I did not get a chance to try the blotting. I will do that shortly.

You had mentioned a possible electrical fault. What can I do to possibly rule the electrical fault out or rule it as the cause?

 

[Trigger 37]

Stuber, after reading again all the posts you've made above,... I'm really confused,...but it's nothing new.

I can't figure out if you have a new printhead with new ink carts or if you got a printhead from someone else. It is not clear what happend to the first printhead or ink carts, or if you got a new printhead from Canon or from some second source supplier. So, my suggestion below is to start all over.

I am assuming that you have a clogged printhead and only the black is clogged. I don't think the wet paper towel is going to help you. If it is clogged as much as you have described, it is a heavy duty clog. You need to do some very serious "Soaking". Remove all the ink carts and Cap each one of them so they won't dry out or won't leak. Take your printhead to a laundry sink and turn the water on to medium hot. Let the water run directly onto the filter screen of the printhead where the Black Ink Cart sets. Do this to all the ink filter screens. The ink should run out the the top and bottom of the printhead. Turn the printhead over and run the stream of water directly onto the nozzles. After a few minutes turn the printhead over and look at the nozzles. You should see the color ink coming out of the screens. Keep repeating the cleaning until no more ink comes out. Then get a small plastic container, like the food containers your wife uses to store left overs in the Frig. It only has to be big enough to hold the printhead. Fill the container with 1/2" of Windex-Original with Ammonia D. Set the printhead into the Windex and add some more windex to the top of each filter screen. Let this set over night.

The next day, put the printhead under the same water stream and see if you can get more ink out, especially the black. Turn the printhead over and direct the stream to the black nozzles (They are the larger ones). If the windex did the job, it should have dissolved the clot. When you see no more ink, dry the printhead using an air compressor of about 70 lbs pressure and blow all the water out of the printhead, especially in the back where the logic board is located with the EEprom. Be very careful of rubber cusions that are around each of the filter screens. You can blow them out of the printhead and lose them if you are not careful. Get the printhead totally dry, and then set it somewhere on a paper towel to dry for another 2 hours.

Once it is dry put it back into the printhead. No, the second possible problem you may have had, could have been with your ink cart for the black. If you can, put in a new one. If you think the old one was good, hold it over a folded up paper towel and remove the Cap and touch it to the paper towel. Black ink should come out easily. If it does not, use your mouth and softly blow into the air vent on the top rear of the carts while it is over the paper towel. This will force the ink out of the bottom. Once you get a positive indication that ink is flowing out of the cart onto the paper towel, install all carts back into the printhead and run a deep cleaning cycle,. then print a nozzle check pattern.

My original post told you how to test your Purge unit to see if it was really working at all. You did not indicate if you tested the purge unit and what the results were. The purge unit has to suck ink out of the back ink cart through the printhead to prime the printhead. The ink will not flow with out doing this if the black section of the purge unit is not working. Just because the colors print in the nozzle test does not mean the Black part of the Purge unit is not broken or clogged. Please take the time to respond to my post.