komori doubling

hi 2004 5/28 komori, doubling on the 1st unit, running kcmy + spot . Doubling only happens when running heavy coverage of black on 150gsm paper or less, also only on the operator side towards the back edge, any suggestions?

have checked infeed swing grippers, all impression and transfer grippers and nothing appears to be sticky. Could it be cam followers between 1st and 2nd unit?

cheers
jet screamer


dude's thanks for the reply's I've reset the 1st impression and 1st transfer grippers and that seems to have fixed the doubling, saying that I do see the slightest difference in dot structure on my colour bars between two concurrent sheets so I'm going to replace the cam followers my I have some spare time. cheers

 

Could be setting on impression cylinder grippers. If set on the light side, a heavy coverage can pull the sheet out the gripper slightly.
Is the double happening one in two?

 

Most common cause is dirty gripper pads on unit one imp and trans. You can check cam followers easily enough for play (need to jack the transfer cam follower off the cam with the jacking point on the shaft). If these are ok and the pads are clean its checking swing gripper setting next, then impression and transfer gripper settings. If you aren't experienced in gripper setting on a Lithrone get someone in to check it as it is easy to make it worse.

YG