Might want to have the developer replaced and drum/cleaning blade normally done all together, then run the TCR procedure/Developer Charge, and make sure the counters where cleared. Did you recently replace the drum and the developer if so did you clear the counters for the drum and developer, FIRST? IF not then the copier thinks the new drum and new developer are old. The copier works on the counters that is how it knows it got a new drum and developer. Get new developer and a new drum and have it installed correctly. Ensure Drum Dry is run first, Counters are clear before the unit is yanked out of the machine, then you remove the image unit/drum unit replace the developer/drum and cleaning blade. (DO NOT USE A VACUUM CLEANER WHEN REPLACING THE DEVELOPER static electricity can destroy the sensor located below the developer unit. Then reinstall and RUN TCR Developer Charge. Make sure the fax line and Ethernet cable is removed can't print anything until the TCR is run. Or you will start all over again with new developer and a new drum.

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/normanj_7893313f0751935f