1. The toner in the toner cartridge is unevenly distributed after adding toner.
Solution: Take out the toner cartridge, shake it horizontally with both hands for a few times, and then put it back. The printed words will be even. It is recommended to replace the toner cartridge or refill the ink as soon as possible
2. The toner may be added too many times, and one side of the toner cartridge is worn out
Solution: You can disassemble the toner cartridge and clean the magnetic roller and toner scraper inside. Generally, it can be fixed. If it doesn't work, replace the worn part.