How do I empty the use ink tank?

This section explains the way to confirm the ink status and the procedure to replace ink tanks. When ink runs out or other errors occur, an error message is displayed on the LCD to inform you of the error. See "An Error Message Is Displayed on the LCD".
When printing from your computer, error messages appear on your computer screen as well.

NOTE

Be sure to install the ink tanks in the correct order indicated by the label on the Print Head Holder.
The machine will not print if an ink tank is installed in the incorrect position.

• With the LCD of this Machine
• With the Ink Lamps
• Getting the Clear Ink Status Information

With the LCD of this MachineMake sure that the machine is turned on, then press the COPY, FAX, SCAN, or MEMORY CARD button. The current ink level will be displayed on the LCD for a few seconds.

(A) Confirm whether any symbols are displayed here.

Color or black ink is low. You can continue printing for a while, but we recommend you to have a new ink tank available.Color or black ink may have run out. See"An Error Message Is Displayed on the LCD".
REFERENCE

The ink status information is also displayed on the screen that appears during printing.
An error message may be displayed on the LCD during printing.

Machine detected ink out condition. See "An Error Message Is Displayed on the LCD" and take appropriate action.
(B) Empty ink tank.With the Ink LampsYou can confirm the status of each ink tank by the ink lamps. Open the Scanning Unit (Printer Cover) of the machine to confirm how the ink lamps light or flash.

• Ink lamp is on

The ink tank is correctly set and there is enough ink remaining to print.

• Ink lamp is flashing

Flashing slowly (at around 3-second intervals)


Ink is low. You can continue printing for a while, but we recommend you to have a new ink tank available.
Flashing quickly (at around 1-second intervals)


The ink tank is inserted in the wrong position or it is empty. Ensure that the ink tank is in the correct position as directed by the label on the Print Head Holder. If the position is correct and its lamp flashes, it is empty. Replace it with a new one.

• Ink lamp is off

The ink tank is not set properly or the function for detecting the remaining ink level is disabled.

If the ink tank is not set properly, press the mark on the ink tank until the tank clicks into place. If it does not click into place, make sure that the orange protective cap has been removed from the bottom of the ink tank.
If the function for detecting the remaining ink level is disabled, replace the ink tank with anew one. See "Replacing Ink Tanks".
If the lamps are still off after reinserting the ink tanks, there has been an error and the
machine cannot print. Check the error message displayed on the LCD. See "An Error
Message Is Displayed on the LCD".
Getting the Clear Ink Status InformationClear ink is used only when printing on plain paper.
When Plain paper (Cassette) is selected for Media type and printing begins when clear ink (PGI-9Clear) is low, a message will be displayed in the LCD.

(A) Confirm whether a symbol is displayed here.

The clear ink is low. You can continue printing for a while, but we recommend you to have a new ink tank available.The clear ink tank is empty. See ""The clear ink tank is empty. Replacing the ink tank is recommended." U045" and take appropriate action.
NOTE

• The ink status information is also displayed on the screen that appears during printing.
• Clear ink is used only when printing on plain paper. Therefore, it is possible to print on photo paper, or any type of paper other than plain paper, loaded in the Rear Tray, even if clear ink has run out.

The following error message will be displayed on the LCD when the clear ink has run out during printing on plain paper.

Refer to "Replacing Ink Tanks"If you continue printing under the clear ink out condition, see ""The clear Ink has run out. Replace the ink tank." U165/U166" and take appropriate action.When the clear ink hasrun out, printing on plain paper from the Cassette is not possible. The fax, which is received under the clear ink out condition, will be stored in memory.
NOTE

It is possible to print on photo paper, or any media type other than plain paper, loaded in the Rear Tray, even if clear ink has run out.

Hi, try these two links, they might be of help. http://canoncanada.custhelp.com/app/answers/detail/a_id/11015/~/lcd-error%3A-error-c000
and
http://fix-your-printer.blogspot.com/2011/04/how-to-solve-error-c000-on-canon-pixma.html

An ink tank which has once been empty is
installed. Replace the applicable ink tank with
a new one.
Printing with a once-empty or refilled ink
tank can damage the print head.
If printing is continued without replacing the
refilled ink tank, press the Stop/Reset button
for 5 sec. or longer to record the use of a
refilled ink tank.

refilling the tank does not solve this problem, canon design this printer to have their ink tank replaced, so do not worry too much about the ink level, as long as the printer prints you are fine....all you need to do is refill every time the print quality is not good, don't wait for the ink to dry up, this could cause damage to the print head.

If the error message is only "magenta/cyan low", it doesn't cause any error. The low message stays after replacing ink cartridges if they're replaced too early (before they're indicated as actually empty), it doesn't cause the printer to not work.
However, some other problem might be faulty, or there might be another error message. Try emptying printer queue and print from Ink Management -> Menu/set (twice) to check wether the problem is with communication from pc or if the printer actually is unable to print.

Here are all the flashing explanations:

Two flashes: Out of paper or paper feed error

Reload the paper correctly and press the RESUME/CANCEL button.

Three flashes: Paper jam

If paper has jammed in the printer, clear the jam, reload the paper in the printer correctly and press the RESUME/CANCEL button.

See Paper Jams

Four flashes: Empty ink tank

If you press the RESUME/CANCEL button, it will continue printing with an empty ink tank. After printing is finished, replace the ink tank immediately. If you continue printing with an empty ink tank, it may cause damage to your printer.

Refer to your Quick Start Guide for instructions on how to replace an ink tank.

Five flashes: No print head installed/Defective print head

Install the print head. Also, ensure that the protective tape has been removed.

If reinstalling the print head does not solve the problem, replace it with a new one. Contact the Customer Care Center.

Eight flashes: Waste ink tank almost full

The printer has a built-in waste ink tank for the ink used during print head cleaning. Eight flashes indicates that the waste ink tank is nearly full. Press the RESUME/CANCEL button to cancel the error so you can continue printing. Before the waste ink tank becomes completely full, contact the Customer Care Center.

The remaining ink level cannot be correctly detected. Replace the ink tank and close the Scanning Unit (Printer Cover). Printing with an ink tank that was once empty may damage the machine. If you want to continue printing in this condition, you need to release the function for detecting the remaining ink level. Press and hold the Stop/Reset button for at least 5 seconds, and then release it. * With this operation, releasing the function for detecting the remaining ink level is memorized. Please be advised that Canon shall not be liable for any machine malfunction or damage caused by refilled ink tanks. See “Replacing an Ink Tank” on page 46.

Solution: Insert one of each color ink tank MP830

New Page 1 More Than One of the Same Ink Tank is Installed When installing or replacing an ink tank, only one of the following ink tanks should be installed. If the ink tank is not installed correctly, an error message will display.

1. Confirm that the printer is powered on and press the Open button. (The paper output tray will open.)
   
   
   
   
2. Lift the scanning unit (printer cover) completely. (The print head will move to the replacement position.)
   
   
   
   Note: When the scanning unit (printer cover) is opened more than ten minutes, the print head moves to the right side. If this occurs, close the scanning unit (printer cover), and open it again.
   
   
3. Open the inner cover.
   
   
4. Press on the tab to release the ink tank, then remove it from its slot. If you are replacing multiple ink tanks, make sure to replace one by one.
   
   
   
   
5. Insert the ink tanks into the print head. Note: Press the mark "PUSH" on the ink tank firmly until you hear a click.
   
   
   
   
6. Ensure that all the ink tanks are installed properly and the ink tank lamps light red.
   
   
   
   <7> The ink tanks are installed properly.
   
   <8> The ink tanks are not installed properly.
   
   Note: Ink Tank LampYou can check the status of each ink tank according to the way its lamp flashes.
   
   • - On: The printer is ready to print.
     
   • - Slow flashing (at about three second interval): Ink is low. Prepare a new ink tank.
     
   • - Fast flashing (at about one second interval): Ink tank is empty, or the printer is not ready due to an error.
     
   • - Off: An error has occurred and the printer is not ready to print.
     
     
7. Close the inner cover and the scanning unit (printer cover). Note:
   
   
   
   • When closing the scanning unit (printer cover), be careful not to jam your finger.
     
   • When starting printing next time, the print head cleaning launches automatically.

You say the "original" is 3 months old? You are out of ink. Replace the cartridge. Even when there is still a little ink in the "tank" it reports back to the printer as empty. And yes it will go through all its checks and still show empty. They don't last forever even if you don't use the printer. The ink evaporates out over time.

I had the same problem -- error message saying two cyan print tanks installed. Nothing helped (including disconnecting power cord). Then found I had an older cyan print tank still in its pack on hand, Installed that. No further problems. Assume this means print tank giving error is part of a faulty batch so am returning to retailer for refund from Canon.