Develop C255C error: what it means
C255C is a toner-density measurement fault that often appears after a developer unit has been replaced.
What C255C means
The machine could not complete its toner-density measurement. On these machines it tends to show up straight after a developer unit is changed and the toner adjustment is run, and it can point to the sensor being unable to read the developer or to a developer unit that needs attention.
Applies to: Develop ineo and Konica Minolta bizhub colour machines. The exact wording of a code can differ between models.
Common causes
- The developer unit was recently replaced and the adjustment did not complete
- The sensor cannot read the developer (dirt, build-up or a loose connection)
- A door was opened during the adjustment
What you can safely try
- Switch the machine off at the power button, wait about 15 seconds and switch it back on.
- Make sure every door and cover is fully closed.
Don't open the machine or touch the fusing unit. It gets very hot and has live parts.
When to call an engineer
Call an engineer. The adjustment and any sensor or developer work happen in service mode.
Stop being the person who deals with fault codes
On a CBE lease we can keep an eye on your machine remotely, so we often know about a fault before you do, and an engineer can be with you fast. You also get a 3-hour engineer response. Already in a contract? We can buy you out.
Remote monitoring only picks up some error codes, not all of them, so we can't promise to spot every fault before you do. Ask us which ones apply to your machine.
Frequently asked questions
Will switching off and on clear C255C?
Sometimes. A restart clears a one-off glitch, but if C255C comes straight back the machine has found a real fault and needs an engineer.
Can I keep using the machine with a C255C error?
Usually not. The machine normally locks out printing until the fault is cleared. Try the safe checks on this page once; if C255C returns, stop and call an engineer rather than forcing it.