Feeder Front Lays and Non-uniform Paper Size, SM52

I have been trying to make sense of the following:

There is a small problem with the guillotine I have causing the paper to have a size variation of + 0.5 mm from one side. So, one side of the paper stack is 100% straight, the opposite end is non-uniform.

From what I understand, if the paper was loaded on the feeder with the extra (0.5 mm) left on the far edge (away from the reference edge/Front lays), the printed registration should not have any differences.

Can someone please explain why the opposite is happening? The variation in size of the paper is effecting the registration accordingly.

Thank you.

 

In an ideal world, paper should be back trimmed, but often times, paper is loaded from a stack straight from the mill and paper will vary in size, it shouldn't really matter if you have some variation, as one side will always be registered as long as it is no more than a few millimetres.

 

Hi sir:

Am attaching in PDF, a complete understanding from Cutting in Practice for Polar, and you will a more ideas, and fix it.

 

Dear Mr. Fawzi,
It your paper is not trimmed by 90°, then the side lay will not pull the sheet fully along the lay and you will face problems in the pre-press machines because the mechanism of the post press machines is different and the position as well.
If you want to check your front an side lays, print the printed sheets again, and check the registers as follows:
In circumferential direction check the registers at lead edge only OS and DS.
In lateral direction check the lateral register at the used Side lay only.
Hope this will help.
Good luck.