Ghosting on Black Copies C451

**Eugene74** · 09-15-2010

Hi there

Try to scan in a sample but even on 600dpi it doesn't show on the scanned file, so I'll try to explain to the best of my ability. The problem seems to fluctuate, sometimes darker ghosting than other times. We have had this problem in various degrees for the last 700,000 copies. Everytime the problem comes up we replace parts (different parts) and it seems to go away for a while, just to return later. The majority of the copies done are black, this problem only occurs with black copying or printing. If there was any colour on the page together with bold black printing the problem does not occur.
The following has been done to try and rectify the problem:
Replaced the black dev units
Replaced the MFP board
Tried different firmware versions
Did the black I.U. modification
Replaced transfer belt and rollers.
Did transfer settings as per bulletins
Varied fuser transport speed.
Various other settings as per bulletins.

I'm now completely out of ideas.

Many Thanks.

**Eugene74** · 09-15-2010

Saw that somebody had similar type of problem on C550, gona try it and will let everybody know.

c550

**fixthecopier** · 09-15-2010

Did you do the basics? Did you clean the lens on the printhead with the wand. Whenever I have a c450 ghosting black, I just use the wand and scrub the lens and it goes away.

**Eugene74** · 09-15-2010

Thanx for the input fixthecopier. I've just came from the customer, cleaned everything including the printhead lenses. According to my earlier post, that somebody had problem on C550 I followed the suggestions, stuck piece of tape at guide plate, but didn't seem to have sorted out the problem. Then as a last resort we removed the "Blue Resistor" behind transfer roller assembly, and our ghosting dissapeared. I'm not to sure what the resistor is there for, and if I fixed a fault with another fault. Try to look through service manual if there is an explaination to the resistor, but no luck. Going to order the guide plate modification and put it in and then if need be, put resistor back in place. If anyone know what the resistor is there for please let me know, seems like it got something to do with grounding or maybe static discharge..... Not to sure.

**Konica_jr** · 09-15-2010

maybe you have to change the laser unit assy or try a " data clear "

**minimerlin** · 09-15-2010

Originally Posted by Eugene74

Thanx for the input fixthecopier. I've just came from the customer, cleaned everything including the printhead lenses. According to my earlier post, that somebody had problem on C550 I followed the suggestions, stuck piece of tape at guide plate, but didn't seem to have sorted out the problem. Then as a last resort we removed the "Blue Resistor" behind transfer roller assembly, and our ghosting dissapeared. I'm not to sure what the resistor is there for, and if I fixed a fault with another fault. Try to look through service manual if there is an explaination to the resistor, but no luck. Going to order the guide plate modification and put it in and then if need be, put resistor back in place. If anyone know what the resistor is there for please let me know, seems like it got something to do with grounding or maybe static discharge..... Not to sure.

The mod mylar is the fix, normal electrical tape does the job as well but you need to shape it like the mod kit! I have used this on many occasions..it works!

**jackson** · 09-16-2010

part no A00H703400

**Eugene74** · 09-16-2010

Thanks everyone, and this is the part no. I also got, but seems to me that our HO never brought it into the country or maybe under another number. But definitly going to make a plan to get it.