This varies by model, but for most compatible printers (e.g., MG2520):
Weigh risks vs. benefits; most users should seek official service or replacement. canon service tool 1050.exe download
The tool should auto-detect the USB printer. If not, click “USB PORT” and select the active port. This varies by model, but for most compatible printers (e
Launch service tool v.1050.exe on a Windows PC (Windows XP or compatibility mode is often recommended). This varies by model