First, please print the nozzle check pattern to determine whether the ink is ejecting properly from the print head. To do this, please follow these steps:
1. Make sure that the machine is turned on, then load a sheet of A4 or Letter-sized plain paper in the Auto Sheet Feeder.
2. Open the Paper Output Tray and then open the Output Tray Extension.
3. To print the nozzle check pattern:
a. Press the Setup button.
b. Select Maintenance, then press the OK button. The Maintenance screen is displayed.
c. Select Print nozzle check pattern and then press the OK button. The pattern print confirmation screen is displayed.
d. Select Yes and then press the OK button.
The nozzle check pattern is printed and the pattern confirmation screens are displayed alternately.
Examine the nozzle check pattern on the LCD of your PIXMA MX780 and you can also compare it to the example that has been attached to this message. Check the pattern to see if any lines are missing. Missing lines or no ink appearing on the paper indicates a printhead cleaning may be required.
If your printout does not match the example, please perform a printhead cleaning by selecting B and then choosing Yes. If these options are not available, please perform the following steps to perform a Cleaning:
1. Press the MENU button.
2. Select Maintenance then press the OK button.
3. Select Cleaning and press OK.
4. Press OK to select Yes.
The cleaning will be performed. After 2 or 3 cleanings, print another test page.
If these troubleshooting steps do not work, feel free to call us at 1-800-OKCANON.