C252 Color shift corr.

[Guest]

Hello,

we have a Bizhub C252 machine which following to her transportation from one office to the other is now showing some bad alignment of black color (rotated of less than 1mm) towards the other CYM colors. In other words, if you look at a text printed page in green color (for example) you can see that the centre of the page is ok, but the upper and lower part is twisted (theu pper part on the left and the lower on the right).

I saw on the service manual of the C350 a very helpful option called Color Shift Correction, which is not present in the C252. This function allow to "rotate" the black color according two direction (clockwise or counterclockwise). It would definitely fix our machines....

Do you know any similar function for the C252 or alternatively do you think it is possible to find the above function on updated firmware/s (if any)???

Thanks in advance for you suggestions/comments.
Best regards

[acusso1234]

Bh C350/351/450 are all LED BAR based, instead of Bh C250/252 that are LASERS based. This explain why you don't find the "Color Shift Correction" on a C252. For me your problem is Transfer/Sensors related. Try also a cleaning of the black laser, because during the calibration the printer starts reading black patches and basing corrections on this.

[boanda]

u have screws under every laser for calibration
or go to service mode-machine-Color Registration Adjustment
be careful!!! those r very different ways for Tweaking. Its very important to see is the black color twisted on opposite angles or on same side to decide on what way to fix it

[Lungo72]

Thanks

@acusso1234 many thanks for the explanation

@boanda many thanks your suggestion. Black color is effectively twisted on opposite angles. No way to fix with color registration as it simply shift all colors in paralll. Would the screw twist the black makng it a rotation or same as above?

[Lungo72]

GREAT! Finally I fix it. The screws made the job...

Thanks a lot for the great help, really appreciated!!!

Best regards

[Stirton.M]

The recommendation to adjust the screws was, well, to put it bluntly, wrong. If the machine was fine in the shop but out of alignment when at the customer location, odds are high that the black laser unit was bumped out of place. Visual inspection of the lock clips and laser body position should have been performed first. Then, if necessary, do the laser adjustment described above. The colours are aligned to the black unit. Refer to service manual, 14.3 PH unit mechanical adjustment for directions on how to perform this. Failure to properly adjust will simply lead to other problems with respect to laser alignment.

[CompyTech]

Stirton.M

"The recommendation to adjust the screws was, well, to put it bluntly, wrong. If the machine was fine in the shop but out of alignment when at the customer location, odds are high that the black laser unit was bumped out of place. Visual inspection of the lock clips and laser body position should have been performed first. Then, if necessary, do the laser adjustment described above. The colours are aligned to the black unit. Refer to service manual, 14.3 PH unit mechanical adjustment for directions on how to perform this. Failure to properly adjust will simply lead to other problems with respect to laser alignment."


He is right, you never adjust the black one according to the manual. Chances are you probably knocked something loose maybe spilled toner on a sensor or something. You might even have a bad black PH. those are a pain to get to and even check. but i would make sure they're not knocked loose. Then do alll the stabilize and gradation adjustments etc.

[boanda]

The recommendation to adjust the screws was, well, to put it bluntly, wrong.

Cool, I respect that.
...But every weaker color machine I saw has a problem as
Lungo72 said.Someone notice that as soon as he/she see first copy,mostly not! I know that u fix cmy lasers according to black, but its easier to rotate screw for black laser one click(~0.5mm) and solve problem then the others tree.
I can guaranty machine will work fine! otherwise i will buy the newone to Lungo72!