Canon S900 - Manual (Page 123)

Print Quality is Poor or Contains Errors 123
Troubleshooting
Straight Lines are Misaligned
■ Align the printhead.
Ensure that you align the printhead every time you install a new printhead.
Windows
1
Open the Printer Properties dialog box.
2
Click the Maintenance tab.
3
Click Printhead Alignment.
Follow the instructions on the screen.