After investigating the incidents, Canon believes that the heat generation and/or smoke is due to ink leaking, over time, into the print head's electric insulation sealant. This may result from either of the following:
- Impact damage to the print head, such as that resulting from dropping the print head or otherwise causing the print head to strike a hard surface after removal from the print head package.
- The sealant is exposed to certain solvents contained in the printer ink. In most of the cases in which there was no sign of impact damage to the print head, ink components not used in Canon-genuine inks were detected.
The likelihood of such an incident is remote. Moreover, tests indicate that this condition should not pose a safety hazard for users because the printer components surrounding the print head are non-flammable at the temperature ranges involved and because the heat generated due to damage to the print head is below the ignition temperature of paper or any printer components.