Description: Printed vertical black lines

Possible Reasons:
- Wiper blade notches or deformation, leasing toner leave on the OPC when rotating OPC, or wear lines on PCR, please replace the toner drum in this situation
- Coating wear ring of fuser roller can be seen after opening the back cover of the machine , replace the toner cartridge, printing test vertical black line position is the same, it means that the fuser roller of printer is worn.
Process 1: The problem stopped after replacing the new toner cartridge
Toner cartridge defected.
Process 2: The problem still exsits after replacing the new toner cartridge
Printer problem/batch complaints identification