Xerox 260 - Black "Marbleized" Effect

[gadgetx23]

Anyone have an idea of what might cause this on the black print? I've tried different calibrations (from ColorWise), different stocks, new drum, new fuser... nothing seems to help.

This is only on the black toner, and is most noticable on darker screens. Solid black actually looks ok. The sample attached is 80% black. The other 3 colors at the same percentage, same stock/calibration look fine.

Any suggestions would be appreciated!

 

[cjwworld]

is this machine able to calibrate? most need to be calibrated.. Thats my guess

 

[Craig]

What type of paper are you trying? If it has a rough finish it will look like crap. Try Hammermill Color Copy or Boise Enhanced, see if that makes a difference. It looks to me like you may have some crap on the charge corotron as well, there is a dark line at the bottom, although I am not a tech.

 

[gadgetx23]

Thanks for the responses.

The machine is calibrated using colorwise.

The stock shown in the scan is Xerox 12pt, C1S. I've tried various Hammermill, Sterling, Utopia, Xerox, etc... gloss, matte - doesn't make a difference.

 

[cjwworld]

are you using xerox brand toner? I heard some toner in laser printers doesn't adhere if its a cheaper toner or if its a bad cartridge.. Just a thought

 

[tiger_scout]

Black mottle is possibly black developer and developer housing.

 

[che.c]

I'm with tiger_scout on this one, it's the dev. Try taking out the drum and wiping the blade, that'll get you a few better prints, but it probably needs changed.

That said, one-colour greys are cack in these printers anyway, so don't expect too much. I just had the drums, IBT belt, devs and fuser swapped out on a 240 there recently and it wouldn't do much better a job on 80% black. 40% usually looks good though, so if you're getting bad mottling at that tint as well then there's definitely something up.

However if you're using cheap and nasty stock that looks like about right to me.

 

[gadgetx23]

Yes, it is Xerox toner.

The service guy should be coming in today; I was wondering if developer/housing would cause this. I would guess that's probably what he'll try.

I do use a variety of higher quality stocks. Single color grays have been crap on this machine since it was new... so that's the nature of this machine, huh?

 

[Dana Cowe]

The Xerox DC260 printer's print speed is 60 ppm color, and 75 ppm black. Furthermore, at those speeds, it utilizes a heat & pressure based fusing system. A black full-bleed page (such as your example) will actually require more fusing time (not less). Therefore, at the 75 ppm speed the toner saturation can become uneven ("marbelized").

I'd recommend trying the following: Mix your black with the slightest amount of any dark color (other than black). If you'd rather not mix the colors, simply place one tiny dot of the dark color in a discreet location on the page. The presence of the color will force the DC260 into color-mode (60 ppm). The slower speed may help with maintaining a more even toner distribution

If the above does not fully alleviate the problem, try a new photreceptor and fuser module. Any adjustments your tech can do to cause more toner to be laid on the page (without background in non-image areas) during image transfer, may also help.

 

[Craig]

The Xerox DC260 printer's print speed is 60 ppm color, and 75 ppm black. Furthermore, at those speeds, it utilizes a heat & pressure based fusing system. A black full-bleed page (such as your example) will actually require more fusing time (not less). Therefore, at the 75 ppm speed the toner saturation can become uneven ("marbelized").

I'd recommend trying the following: Mix your black with the slightest amount of any dark color (other than black). If you'd rather not mix the colors, simply place one tiny dot of the dark color in a discreet location on the page. The presence of the color will force the DC260 into color-mode (60 ppm). The slower speed may help with maintaining a more even toner distribution

If the above does not fully alleviate the problem, try a new photreceptor and fuser module. Any adjustments your tech can do to cause more toner to be laid on the page (without background in non-image areas) during image transfer, may also help.

Keep in mind by forcing it into color mode you will also be charged for color clicks.