Canon i-SENSYS MF5840dn

Completely blank

No image prints

Cause	Solution
1) The laser shutter open/close projection part of the cartridge is damaged	Replace the cartridge.
2) The laser shutter arm and laser shutter are malfunctioning or damaged	If the laser shutter arm or laser shutter does not move smoothly or if the part is damaged, replace any defective parts.
3) Poor developing bias contact with the cartridge	Clean the contact if dirty.
4) The high-voltage power supply is defective	Replace the engine controller unit.

All black

Image is all black

Cause	Solution
1) Poor primary charging bias contact with the cartridge	Clean the contact if dirty.
2) The primary charging roller is defective	Replace the cartridge.
3) The high-voltage power supply is defective	Replace the engine controller unit.

White spots

White spots appear in image

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Cause	Solution
1) Poor contact exists to the static charge eliminator	Clean the contact if dirty.
2) The transfer roller is deformed or has deteriorated	Replace the transfer roller.
3) Poor contact exists between the transfer roller and its shaft	Clean the contact if dirty.
4) The high-voltage power supply is defective	Replace the engine controller unit.
5) Scratches/stain on the Drum	Replace the Cartridge.