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Dave10
12-15-2011, 07:10 PM
We have a C252 with about 400k prints on it. The copies/prints are uneven front to back. The side at the rear of the machine is lighter than the front. It does this when copying from the glass and also when printing. If you print out the halftone grids from the test menu, and you lighten the density, the one end almost completely fades away, whereas the front end is still strong. When copying, the same thing. The part to the front of the machine is always darker. We have tried a new belt assy., X-fer roller, and I.U.s. We have cleaned the printheads and tried all the voltage settings. We are stumped. Any suggestions?

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12-15-2011, 09:16 PM
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bojans
12-15-2011, 09:20 PM
Did you clean laser?

Dave10
12-22-2011, 03:01 PM
We did clean the lasers. After doing more digging, we discovered that when printing the test grid, it only shows on light density. The problem is MUCH more noticable when copying. Checked the positions of the optics. Cleaned mirrors and CCD. No improvement. Anyone else seen this?

copymech
12-22-2011, 03:10 PM
Just currious, Have you run single color C,M,Y,K to see if the fade is on each color.

Dave10
12-22-2011, 04:43 PM
Just currious, Have you run single color C,M,Y,K to see if the fade is on each color.

We did run the individual colors, in print and copy. When printing, it fades front to back only when set to very light density. When copying, however, the fade front to back is very much more pronounced. Also, to correct an earlier typo, the machine has less than 200,000 prints, not 400,000. We have cleaned everything inside, including print heads, tried new I.U's, new belt unit, and fuser. We cleaned optics. Hasn't anyone seen this problem before?

Dave10
12-22-2011, 09:34 PM
Forgot to mention, does this when copying from glass. No feeder.

AjitN
12-23-2011, 03:22 AM
Forgot to mention, does this when copying from glass. No feeder.

I had similar problem with C220, which got resolved by replacing PH Assy. In your case I tink you have done almost everything. Try swapping right hand side door Assy. OR check for door latches for proper contact of transfer roll with Transfer belt.

Hope this help, best luck.
Ajitn

Dave10
12-23-2011, 05:28 PM
Is anyone familiar with the service mode settings called Scan Calibration and Line Mag Setting on this machine? The manual is a little vague. Where do the numbers come from and how do you plug them in?

RRodgers
12-23-2011, 06:55 PM
Stop it half way, how does the image look on the transfer belt?

Dave10
12-28-2011, 09:59 PM
Hard to tell with the color of the belt being dark, but seems to look the same as the copies.

DigiMan
02-01-2013, 07:38 PM
Hard to tell with the color of the belt being dark, but seems to look the same as the copies.


Hello everyone,im a young technician and i've encountered the same thing recently.
I did everything you gyus discussed about even stopped the machine while printing a graddation pattern and i noticed
the uneven density starting on the drums(cleaned PH unit).
Has anyone found a permanent solution?

AjitN
02-02-2013, 03:50 AM
What about cleaning / replacing erase lamp OR PH. Try cleaning with some good solvent which will not leave any stains on polygon motor, lens & mirrors.
Hope this helps.

DigiMan
02-02-2013, 08:06 AM
What about cleaning / replacing erase lamp OR PH. Try cleaning with some good solvent which will not leave any stains on polygon motor, lens & mirrors.
Hope this helps.

Thing is i did clean the lamps and PH inside and out as you mentioned but the problem persists :mad:.
Also another thing that got me confused is that the transfer belt is supposed to be changed at
260k,the machines meter is at 220k and if you look at the parts life the belts life is below half.
The only thing i've changed so far are the drums which are almost brand new.
:confused:

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