Canon MP780 with a "wrong cartridge" error code

[zman]

My printer kicked out this code when I refilled by cartridges the last time at Cartridge World. I called Canon tech support and they said it was probably a bad cartridge as you can only refill a cartridge so many times. They suggest to buy new cartridges with the most likely culprit the black cartridge as that was the most used. Before I go and spend $ on buying cartridges I wondered if there was a way to tell which one was bad plus my other concern is what if I change them all only to find out that I need a new printerhead, as that was one of the possible fixes too. My final thought is to junk the printer and buy a new one, as by the time I spend a $100 on parts I can go buy an inexpensive printer for about the same price.

 

[embguy]

Clean the ink sensor. The ink sensor may be cover with ink due to cartridge overfill. The ink sensor is located on the track where the printhead move along. It detects ink in each cartridge when the printhead moves over it. When the sensor is covered with one ink color, it will report the same color for all cartridges. Therefore, it generates "wrong cartridge" error.

 

[ghwellsjr]

The printers that use chipless cartridges (BCI-3,-5,&6), like the MP780, can only sense when a cartrige with an empty reservoir is inserted into the print head. Any other condition, eg, no cartridge, full cartridge, half-full cartridge, incorrectly inserted cartridge, ink covering the sensor, all look the same to the printer. This is one of the major reasons Canon went to the chipped cartridges, so that the printer could tell the difference between these situations.

When these printers complain about the "wrong cartridge", they are refering to the print head, not any of the ink tanks, which is what we usually call cartridges.

Try removing all the ink tanks and then the print head. Your printer should then tell you to insert the cartridge. If you're lucky, it will then detect the print head correctly and you're good to go. If this doesn't happen, remove the print head, unplug the printer and try cleaning the contacts on the back of the print head with a pink or other soft eraser. You can also try to clean the mating contacts on the back of the carriage. Be very careful to not let any liquids (ink) migrate over to the electronics on the back of the print head.

 

[zman]

Today must be my lucky day! I followed your instructions and walla, it worked! I believe removing the printhead and letting the printer ask for it then inserting it did the trick. I wasn't sure where the ink sensor was, is it on the front track or back? Regardless there was no ink anywhere to clean up. Thanks for your help, you truely are the Master!

 

[ghwellsjr]

Thanks. Now if I could only be so lucky as to get my MP780's working.

But to answer your question, the ink sensor is located just inside off to the left when you open the cover and fold the two flaps down. Look for a shiny piece of sheet metal a couple inches wide. It has a hole towards the right with a black plastic block containing two tiny optical "lens". One of these is a light source (probably invisible infra-red) and the other is a light sensor. Under most circumstances, the light shining up from the source never makes its way back down onto the sensor. When the printer wants to know if any of the cartridges have an empty reservoir, it moves the print head across the source/sensor. The prism contained in the bottom of each reservoir will reflect light if there is no ink on it, otherwise it will appear dark. You can take any cartridge with ink in it, turn it upside down and you will see that the prism will appear light unless it is covered in ink.

Here's another interesting bit of information: if you put in a cartridge with an empty reservoir and close the lid and then replace it with another cartridge with enough ink in it to cover the prism and close the lid again, the printer will think that you have just put in a full cartridge and it will automatically arm a cleaning just before the next time you print something. It does this separately for the large pigment black cartridge and the smaller dye cartridges.

The printer then keeps track of how much ink is used for that cartridge and reports that the cartridge is half full at the appropriate time. Of course if the cartridge started out a little more than half full, it will really be almost empty by the time this happens. (Remember, we are talking about how much ink is in the reservoir.)

At any time that the reservoir becomes empty, the printer will show that the cartridge is low and it again keeps track of how much ink is used. It is now using the ink that is absorbed in the sponge material. At the appropriate time, it reports that the cartridge is empty.

If you understand how all this works, you can use it to your advantage to confuse the printer. But this only works with the printers that have chipless cartridges. The more recent line of printers cannot be outsmarted.

 

[Trigger 37]

ZMan,... I would just add my 2 cents to the other comments. 80% of the time, just the action of unlocking and relocking the printhead will resolve the problem. This action releases and latches the printhead and this wipes the contacts in the carriage asm against the gold contacts on the back of the head.
The wiping action is cleaning the two gold contacts. The othe 8% of the time the contacts have become dirty with ink that is not visible. 2% of the time the eeprom in the printhead is dead and does not respond to the logic card.

Each printing cycles create 1000's of pico liter bubbles that are basically "Spit" onto the paper below. Sometimes the action doesn't make a perfect "Bubble" and results in dozens of Atom size bubbles that burst and go everywhere. They can contaminate everything inside the printer and most of the time they build up a nazty film on the timing strips. If you every had the opportunity to clean one of these strips with a white tissue, you will see the collected ink.

 

[zman]

Thanks for you 2 Trigger, my printer is still acting up though, it will print a few pages fine then kick the "wrong cartridge" error, then I remove the cartridges and printhead, re-insert, it goes throught the auto head align print out then about half way through that it stops and kicks out the wrong code again. I cleaned the contacts on the printhead, what else is going on here?

 

[Nifty]

um... and my mp750 that is in the garage because of the same error... maybe I'll give it a few more kicks.

 

[Trigger 37]

Zman,... Sorry for the long delay in getting back to you. I did not get a notification of your post. There are several possible problems that could cause this error to keep coming back.

1. Did you clean the contact inside of the Carriage ASM. Remember to only wipe them in a downward motion as they are spring loaded. Check each one to see that they are all still working.
2. Check the locking lever to see if anything may be blocking it. It may not really be tight when it is supposed to be locked. As a result, the logic card will get an OPEN signal in the middle of printing.
3. Remove the printhead and clean the contacts using the eraser of a pencil, this will scrub any grease or fill that may have built up. Then clean with alcohol.

All of the "Wrong Cartridge" error conditions are about the printhead and the logic card reading the power on and operating conditions. If any signal does not match what is expected, this is the error you get.

The worst possible problem may be a loose connector inside the carriage ASM or down on the logic card where those cables go. Then you would have to take the printer apart to check those.

Last resort; Try using heavy tape to tape the locking lever hard down. This put much more pressure on the contacts.

 

[zman]

Thanks so much for taking the time to help, I will go through the steps you mentioned. I've already cleaned the contacts but will go through it again. Perhaps the locking lever is the issue I will keep that in mind. We'll see what happens.