Double image on black

We occasionally experience a double image on the black unit with type near the tail end of the sheet or on 1 side of the tail end of the sheet when printing 80 lb coated 12x18" long grain. Can any one offer any suggestions?
I would like to thank previous members for their suggestions with my other issues

 

A bit of a basic answer, but loose blanket maybe ??

Regards.

 

a couple of suggestions
check your infeed brushes, make sure they are down as far as they can go without holding the sheet back, slow down press, turn your air down, make sure your infeed wheels have the even tention.

 

check your packings are correct to blankets as could be any unit causing your doubling. Check your grippers are clean and working properly. Make sure your paers long grain and your inks not too tacky as i suspect. Run a load of waste sheets through press to get ink pulled out correctly(less tacky).Finally make sure the clutch on your black print unit is sufficently tightened as could be too lose with wear.

kev c