Dear User,

The error 091-911 on a Dell 3010CN printer is caused if the Drum is missing or not inserted properly. Kindly reinsert the drum once & ensure the contacts are in place which should fix the error. However, even after reinserting the drum if the error remains then the drum needs to be replaced.

Kindly revert for any more clarification.

Thank you for responding. This is weird, I re-installed the old toner cartridge and the error went away and started working. I don't know if you heard of this but it happened to my printer. Now I installed a new toner cartridge but the print is light. Is there any settings or adjustment for making the text darker? If you have any ideas, please let me know. Maybe it still due to a bad drum but trying to save money. If it is the drum, I might as well buy a new printer since this printer is old.  Thanks again.

According to the symptoms you are saying the problem can be occuring either due to drum or the new toner you are using. If you have a spare toner please swap it and if the issue remains then the drum needs to changed. But if the spare toner works fine then the issue is probably because of the toner you changed the first time.