Scumming on tail edge of SM 102 10 P

I have a customer who's press is scumming on the 7th unit of an SM 102 10 P. On a 28 x 40 sheet, the scumming is on the tail edge middle and Operator side corner. When he goes to a smaller sheet, the exact thing happens, it doesn't dissapear even if he uses a smaller sheet. He has put in a new dampening roller, and has increased the water to get rid of it, but then his print wahes out. Any ideas.

 

If its only happening on one unit its probably settings.

Off the top of my head:

Check form rollers are seated correctly in bearing cups. If they ocilate too much they will cause the scumming.

Check water pan roller that its set evenly. Maybe you need to open slightly on the side to alllow more water through.

 

Thank you Print 101. I mentioned settings and rollers to them, when I was there. They also need to replace rollers, as they have not done so since they bought the press.

 

Prints right. A simple quick check is back all but one form roller off the plate and make pulls adding one at a time. Also need to check ink charge on that unit.

 

I have seen issues with older SM/CD presses within the autoplate that may cause this. Possibly the tail of the plate is not being pulled tight enough. Simply replacing the springs under the tentioning bars under the tail clamp may solve this.