Konica Bizhub C451 Color Registration Off

[Oscar57]

Hi,

I have a C451 that has the Black color out of registration with the other colors. But only on the first side of a duplexed page 12x18. 2nd side is dead on. The strange thing about it is the black is out in the direction the sheet moves, but its out to the left on one end of the sheet and out to the right on the other end?? Since its fine on the 2nd side I've tryed adjusting the paper loop or buckle but that hasn't help. I don't know if there is a adjustment for this? Any input would be appreciated.

[BIG PAPA]

Can you attach samples of the problem? Is it with all jobs or only certain jobs?

[AyJayAreDii]

Check service in service mode the warning counters. If you have a lot of P-14 and p-31 codes then it is the main drive unit which houses a very fine foil decoder disc that gets filthy with dust. its too fine to clean with out damaging. also takes some time to remove and replace first couple of times. Its defiantly not an easy job, but most engineers should manage. But make sure you have the mod that fits above the paper transfer roller first. It is the white almost transparent sticker used to stop static. Not having that causes some double siding trouble.

[spock]

if its out towards 1 side of the page and not the other then it sounds like a skew problem which usually brings up a P-14 warning code.

Has the write unit been replaced recently or the black IU? There was a faulty batch of black IU's a while ago that caused the problem and still pop up every now and then. Its because the black IU is used as the baseline for the adjustment of all the other colors.

Go into techrep and run the 4 color lattice patterns from test mode to get a better idea of the skew. You can manually adjust the write skew correction unit values in techrep to bring it back into line again by eye. I do it all the time. Just make sure you write down the old values though they aint always perfect anyway.