I have a new 300ci with light fill when printing or copying in Mono. Colors are fine and Process Black does look better than Mono. I have replaced the Black Dev & Drum assys, increased and decreased laser intensity, dev bias & AC charges. has anyone solved this?
Thanks!

run 464, ac calibration, select black to "on", under type, select +4 then execute.

Turn you econo mode to off both in copying and printing.

Thanks, but I ran 464 not only when I replaced the Dev Unit, but twice more in subsequent days.
And I did make sure Eco Mode had not been turned on by mistake. Today my client showed me an Excel spread sheet with Blue Highlighted across each row and from the top of the page to the bottom, in 3 different places, were three 3/4" voids. Yet the voids only were missing the black test AND I could see where the Text should have been because it was there as a latent image in the Blue Highlight. The Blue Highlight is not being voided. So, either Black Dev bias or Drum or Transfer charge is
shorting. Any of these will also contribute to my overall light fill in Monochrome. Anyone had any bias or charge issues?

OK, to date I have replaced:
Black Dev, Drum, Transfer Belt & Roller, Dev-Drum Bias HVTs (yes, both of them) Engine & Main PCBs, & the LSU.

Did you ever find a solution to this one? I've got a similar situation.

JD for me this problem started when I replaced the black DV unit to the upgraded unit. The reason I changed it was because of the toner dropping issue. That is now gone but now I have light black density. I talked to hot line they had no clue and attemted to make me think no one else is having this problem. Customer does not complain so I havn't gone further with issue. Good Luck let us know

Have you tried running a normal user maintenance gray scale colour calibration. Don't use colour calibration use gray scale calibration instead. Gray scale calibration goes a step further in the calibration process, more than the normal colours.

Yes guys, I have tried all your suggestions and more. Am working with Tech Rep now. Have my fingers crossed as I have one of the best Reps ever! (and I'm not being sarcastic, the guy does a great job)

Check the toner motor. Pull out the black toner cartridge, cheat the front door, and look at the 2 motors in the rear of the cavity. The upper right one is the "agitation", which should turn all the time. The lower left is the toner add. Cheat the front door, reach in and grab the drive gear to see if you can stop the motor from turning. (If it's not currently trying to add toner, go to Sim 135 and turn the motor on.) On mine, the motor was turning, but if I even put my finger on the drive gear, it would stop. Not grind or error out, just stop. I replaced the motor and worm gear, and the quality came right in. Good luck!

Tcook, tried that, motors are turning stong.
Thanks

Have been battling the same problem on a 250ci, even had our tech rep. out to look at copier. He escalated poor black density issue to engineers, and I'm now told there will be a firmware fix coming. This makes sense to me because as I start to look closely at other TA color machines they seem to have similar density problems, it just is not very noticeable until there are large black solid areas on prints. I'm guessing the last firmware upgrade to fix toner blotches and poor toner yields might have undertoned the developer too much.