Komori 528 sheet marking

[scottsman]

We have a Komori 528 with coater and extended delivery. When backing up a sheet we are getting marking on the back side and cannot find where it is occurring. We have moved and inspected everything we could and still cannot find the problem. We suspect the upswing in the delivery but there is no evidence we can see. We have never had this problem before on any other press and we are a little frustrated. Would appreciate any suggestions.

 

[peter61]

Does the sheet mark even with one side already coated?What do the mars look like?Is your sheet deculer on?

 

[scottsman]

It doesn't do it if we have coated the sheet and it looks like something sharp but not always in the same place from run to run. It will do it with or without the decurler on.

 

[peter61]

Try putting a dirt sheet in(blanket packings taped together)start at the back of the slow down wheels and work the sheets back to the bottom of the pan( use masking tape to secure the packings and make sure there are no raised areas where a gripper might catch it) stopping right before the rails in the extended delivery,this will tell you if the marking is occuring before the rails or after.

 

[neversatisfied]

I to have had this problem on a 5/28 with aq and extended delivery. I traced the problem to the suction on the upswing guide plate. I just reduced the suction or turned it off completely and that took care of the problem. Don't rule out the rails under the extended delivery. I don't have a pit under the press so it makes it hard to trace marking sometimes. Hope this helps, i know the pain.