Vertical black lines / shadow on 6515. Almost new with original parts

Hi all, 

my WorkCentre 6515 is almost new with round about 500 printed pages. All components come from the delivery condition. 

But now i see on every printed site vertical lines. Please see the attached printed scan. 

(It's not so easy to see on the screenshot, but it's on the left side over and under the 2.x from the word Xerox.)

Please, how can help me?

Regards

Christian