mx850 don't print black, cleaned head, new carts, new head, whats next

[skorpian]

Canon MX850

Originally started showing lines while printing black text. Tested all cleaning cycles multiple times - initially this helped. Thereafter removed head and cleaned. I tried several different cartridges, but to no difference. Not a cartridge problem. Printed well for a short period, and but lines returned soon after. This cycle continued until now black text PGI-5 no longer prints at all, even after long soaking / cleaning. I presumed print head, so ordered a new print head. Behold when it arrives, still same problem - NOT print head problem!

Nozzle test fine for colours, but now not printing any PGI-5 pattern at the top.

Anyone know what the problem is and how to fix ?

Also, does anyone have a service manual for this printer that I can get a copy of please ??

Thanks for your help.....

 

[ghwellsjr]

You need to have a properly working purge system in order to get ink to flow through the print head the first time.

Start by doing a nozzle check.
Open the printer cover and wait for the print head to stop in the middle.
Use a flash light to view the two purge pads off to the right where the print head normally parks. They are black rough looking. The one on the right is almost square and is a lot easier to see. The one to its left is rectangular and more difficult to see
Take a syringe, eye dropper, or bent straw and apply some Windex or other window cleaner or just plain water to the two pads. Make sure the liquid stays there. It will make the pads look shiny.
Close the cover and turn the printer off.
Turn the printer back on and do another nozzle check.
Open the cover and look at the pads again. The liquid should be gone on both pads.

Please report what you find.

[EDIT] Since writing the above, I have learned that some printers will not automatically perform a cleaning after cycling power and doing a nozzle check. If your printer immediately prints the nozzle check after cycling power, you will need to manually command it to do a regular cleaning before doing the nozzle check. In this case, you do not need to cycle the power.

 

[skorpian]

Thanks for your help. The pads look different now to when I first inspected them. The water isn't lying on top, but i am guessing there is maybe a small film of water still on it - the color looks different to what it did when I initially looked at them. Its now a lighter color now, and perhaps a bit shinier. Initially they seemed darker with more texture. I noticed however, that when I push on the smaller rectangular pad, there is water right around the very edge in the gap, and as i gently push the pad down, it rises up slightly, but no so much that it floods back over the pad - the larger square one does not do this. Nozzle check is still the same - 100% for colors but NOTHING for the black in the grid pattern.

 

[ghwellsjr]

Sometimes the clog is in the pad itself and can be cleaned. This is a somewhat delicate job because you need to be very careful of the almost invisible timing strip that goes from one side of you printer through the print head and out to the other side. You don't want to damage it or get any ink on it.

If you want to give it a try, here is what to do:
Open the printer cover and wait for the print head to stop in the middle of the printer.
Unplug the printer.
Remove the rectangular purge pad for the pigment black ink. You may need a tool to do this but be careful that you don't let it fall inside the printer.
Take a cotton swab and soak up all the residual liquid from the rubber tray the pad sits in.
Use more cotton swabs soaked in Windex or other cleaning solution to clean the tray
Rinse the pad under warm running water.
Soak the pad in Windex or other window cleaner or soapy water.
Rinse it again.
After no more ink comes out of it, put it to your lips and make sure you can freely blow air through it.
Put some Windex or other liquid in the rubber tray and do the test in post #2 to see if the liquid will be sucked away by the purge pump. If it is, then you're in luck. If not, you will have to take apart your printer to fix it.
Put the pad back in its rubber tray. If one corner is notched, it goes toward the rear left of the printer.

Don't take too long to do this process because your nozzles will be exposed to air and will eventually dry out and clog.

Let us know if this fixes the problem.

 

[skorpian]

Bad luck for me.

Water remains in rubber tray after removing pad, and doing turn off / turn on procedure.

Ok, pulling printer apart, no worries. If possible please provide pics if possible and clear instructions please.

Thanking you kindly again for your assistance thus far.

 

[ghwellsjr]

I have never seen an MX850 so I cannot offer you pictures or instructions for that printer but I have taken apart many MP780 printers and I posted instructions on replacing the waste ink absorber pads for that printer. I would advise you to get a set of these pads for your printer and replace them while you have the printer apart. I posted another thread showing the waste ink absorber pads. Finally, I posted a thread about the purge system which shows pictures and describes how to connect to the tubes coming out of the purge pump. You should study all these posts to get an idea of what you might be facing.

I would suggest that you find out how much it will cost you to have an authorized Canon repair center replace your waste ink absorber pads and to unclog the purge pump tubes. They will probably want to replace the entire purge pump which will cost considerably more and is not necessary unless the design is significantly different than the MP780. That would be a good place to buy the ink absorber pads, too.

Assuming that you succeed in dismantling your printer to do the work yourself, the third link above describes attaching some tubing to the purge pump tubing (but for a different reason). You need to attach longer tubes, at least a foot but preferably three feet, so that you can secure a syringe to the end. You want to inject Windex or other window cleaner or light soapy water into the tubes until it comes out of the rubber tray. Unfortunately, you cannot test your results until you get the whole printer back together again so make sure you get the clog out the first time.

It would be great if you could take pictures and document your progress for all to see. Let us know what happens.

 

[turbguy]

My limited experience with Canon Printers shows that the most probable cause for purge system "issues" is a disconnected hose(s), either at the "pad plate", or within the purge pump itself.

Wayne

 

[ghwellsjr]

I believe a disconnected tube would allow the liquid to drain away immediately.

 

[skorpian]

Thank you for those links. Mx 850 looks slightly different.....

Mmmmm.....Call to Canon repair shop = $185 "for the first hour", paid UP FRONT! Then + whatever parts , if necessary, purge unit quoted around $70 , and ink absorbers around $30. Quick search reveals new mx870 or 860 around $230-250. Its hard to justify getting someone to repair it for me, when the new ones work out to around the same price..... The service guy was good tho, and happily told me his thoughts, and suggested it was unlikely to be a broke purge pump, most likely a blockage, especially as I refill, but "you never know". He also suggested that the mx850 was a good machine and worth repairing....OF COURSE HE WOULD SAY THAT, WOULDN'T HE ?

I've tried to find a service manual for this machine online for free somewhere, but with no success. Ive found one for only a few dollars on Ebay, so I've bought it and am waiting for the download.

BTW I'm in the land Downunder, so that pricing is in Aussie dollars.

I will repost with results when I'm done.

 

[ghwellsjr]

Actually, the service man is correct, the MX850 is the best of the Canon all-in-ones that use cartridges with chips in them. The current models are not built as well and they have smaller cartridges and I'm not sure if there are chip resetters for all of them.

Did you pick up a set of ink absorbers? You really should get them if you are going to take your printer apart.