Image Fit Problem

[discountprinting]

Anyone out there every ran across a 2 color press fit issue where the marks and image at the gripper was dead on, the tail marks and image was dead on, but the middle of the sheet was out by 1mm in the direction the sheet goes through the press??? When I first saw this I did a double take and said it is not possible but the 4 corners of the sheet were dead on accurate but in the middle of the sheet one color was shorter or longer than the other color by approximately 1mm...I am stumped on this one, I am running 8 mil polyester plates off a drum CTP and cut 2 plates across the marks and lined the two plates side by side and the marks line up at the gripper, middle and tail so that tells me it is not an imaging problem with the ctp... Anyone ever seen this? In 25+ years I never have until now....

 

[pdan]

I'm not shocked by this; I wouldn't want to experience it, but after 25 years I can conceive it.
Given that the image is creeping in the direction of travel I would carefully consider the
- plate to blanket pressures. (Excess pressure is dragging/stretching the plate. It is clamped at both ends so it comes back to fit, in my hypothesis.
- blanket to impression. Is the/are the blanket(s) properly tensioned?

Excessive Pressure is never good

If you wanted to check the plates, swing one 180

What press?