oki c5950 black issue

[geocha]

hello guys!
I have this printer for 5-6 months now and definitely drives me crazy!
I installed 4 new 100% compatible cartridges from a dealer i trust and never had issue until now.The problem is when i print black text.
I just can't get a constant quality black text.Some times the text is black with gray spots,sometimes inconsistent not crisp with rough edges and other times it's decent....I ran some cal.cycles but nothing changed.The printer is brand new with 2500 pages printed and the drums at 85%.
I also tried to calibrate from the system maintenance menu but there isn't much to understand there..

Can somebody help me?

ps:The above pic is from the oki , the bottom from my epson c1100

[manuals4you]

Replace with OEM cartridges.

[geocha]

Actually oem black is much worst.The text is better form but totally gray!Unacceptable for black laser.Here is the oem print.
Older oki like the 3200,5000 series - 5600 was excellent on black printing.Then,with the multi-level printing they changed the black with this awful gray.Unbelievable! I can assure you that on paper is much much worst!

The second one is from the oki c5250.Wonderful black!

[Eric1968]

Have you cleaned the LED-Heads?

[geocha]

Have you cleaned the LED-Heads?

Yeap!It seems to have a sensor issue.In factory mode, in which the printer doesn't perform density and registration calibration automatically, the black is black enough.In shipping mode the prints are really bad.