Canon G4000 series Online Manual page 457

2900
Cause
Scanning print head alignment sheet failed.
What to Do
Press the printer's OK button and follow the instructions below.
• Make sure the print head alignment sheet is set in the correct position and orientation on the platen
glass.
• Make sure the platen glass and the print head alignment sheet are not dirty.
• Make sure the loaded paper is correct.
For automatic print head alignment, load A4 or Letter-sized plain paper.
• Make sure the print head nozzle is not clogged.
Check the print head condition by printing the nozzle check pattern.
After carrying out the above actions, try manual print head alignment.
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