marking problems on sm 74

we are currently running a SM 74 10 color,,,we have had some issues with the back of the sheets marking in the delivery,,was wondering if anybody has had the same problem,,,

 

Do you have a standard delivery or an extended delivery? On the SM74 the standard deliverys had a bit more marking issues than the extended however in either case it can be controlled somewhat with the air settings on the venturi plates. Very important that all pumps that supply air to the guide plates are working and the airsettings are correct. Its very easy to have one pump not working and not even know it. Also make sure all hoses going to the plates are in tact. Not uncommon for these hoses to break causing less air to get to the plate and then marking will follow.

 

Is the air bed perfectly clean and polished.
Make sure there is not too much air blowing down from the fans over the slowdown wheels.

 

Willard, I faced this problem couple of years ago on an 8color. I strugled a lot with the machine and the paper, air humidity , blankets etc etc. The problem was the underpacking under the transfer cylinders. It was made out of plastic and was causing static electricity. Keep it in mind , in case that noothing else works

 

Thanks for all the suggestions,,,,,will be back at it in the morning at least with a few new ideas,,,,Thanks again