Version 3
imagePRESS 1125P Customer Expectations Document
Page 60
15.4 Paper Grain and Curl
Paper grain and curl can dramatically affect the reliability of machines utilizing an
electrostatic process like the imagePRESS 1125P. Paper used in an offset press is
usually cut for short edge feeding. This type of paper is not as reliable as paper
made for machines utilizing an electrostatic process, which is cut for long edge
feeding. Also, the composition of electrostatic paper is different from offset paper,
and produces better quality results in a digital press machine. When selecting
paper for the imagePRESS 1125P choose paper intended for use in electrostatic
machines, such as laser printers and copiers.
If paper jams or poor print quality occur when paper is fed from the optional paper
decks, paper curl is often the cause. The paper stiffness, direction of curl, and
amount of curl have a strong influence on how well the paper is transported
through the machine. If paper is curled, straighten out the paper by gently curling it
in the opposite direction to which it is curled.
Paper stiffness depends on the direction of the paper grain. Paper tends to curl in
the direction parallel to the grain.
IMPORTANT
•
When using LTR or smaller paper sizes we recommend using paper with a grain
parallel to the long edge (A). For paper sizes larger than 11” x 17”, we
recommend using paper with a grain parallel to the short edge (B). When using
coated paper thinner than 105 g/m
2
, we recommend using paper with a grain
perpendicular to the feeding direction of the paper.
•
If you are using 12 point, 243 g/m
2
paper in the Saddle Stitch mode, it is best to
use paper that is cross-grained. Thick, long grain LTR paper will not fold as
easily. Cross-grained paper is more flexible, resulting in a smoother crease along
the direction of the fold.