Roller streaks in Cyan Unit of Mitsubishi L-750S heat set web offset press

[Puneet Aggarwal]

We are facing problem of roller streaks in Cyan unit(both upper & lower side) on our 1996 model Mitsubishi L-750S Heat set machine. This problem is more prominent in highlight area & increased speed beyond 15000iph. Press has Dahlgren dampening system. All roller were changed 1 month back only.
Please help!

 

[veejay18]

I believe L750s is double circumference blanket press, can you specify the exact location of streaks is it following

1 Near gripper area
2 In the middle portion
3 alternate copies or all copies

 

[Penguin1100]

had this issue before ....try lowering roller strips of form rollers to plate and oscilators ...also try to back off one of the form rollers ....depends how far back your roller line shows up .... you will have to measure the roller circumfrance to determine which one is causing the problem

 

[Tlang]

Also check to make sure they're not ductor marks, check the ductor timing (unless you have continuous feed inking). Couple of presses I've worked on have made strange roller marks from ductor timings being out of whack. Secondly check your bearer pressure and make sure what you're getting is a roller mark. If it is only showing up when you run thick paper then you might be getting a little gear mark or blanket slip marks. The M600 I work on gets blanket slip marks in the middle of the sheet when we run heavy stocks like 9pt cover