PRESSROOM SAFETY
45
FOLDER
It is possible to overfeed or starve a folder by abnormal conditions in the rollstand or perfecting units. The
following are a few examples:
1.
Infeed system:
Although at the other end of the press, the infeed system in conjunction with the dimensions of the folder
cylinders determines the exact cut-off. Therefore excess paper fed to the folder will not only cause poor
performance, but will result in a loose or baggy web between the perfecting unit and folder.
2.
Rolls Top of Former (R.T.F.):
The driven rollers in the folder overhead gathering section draw the web from the printing units and propel the
web into the folder. The spring loaded trolleys on the R.T.F. should be adjusted firm enough against the webs
to obtain full benefit of the driven rollers. Insufficient trolley wheel pressure allows the webs to wander and
contributes to looseness. Therefore trolleys must furnish enough nip to pull the proper amount of paper into
the folder. Conversely, do not use excessive trolley wheel pressure as this may constrain the web flow.
Carefully monitor this setting until a proper balance is achieved.
3.
Slitter wheel:
When slitting the web, be certain the slitter wheel is sharp. A dull wheel can actually impede web travel and
create a problem. With a power slitter, be sure the blade is properly set for depth and clearance (see folder
section for specifics).
4.
Dirty former:
Be sure the former is clean. A build-up of ink on the former will tend to impede the flow of the inner web.
5.
Folder nipper rollers:
As the webs flow over the former they are drawn into the folder by the nip rolls and it is absolutely essential
that these rolls have enough bite of the multiple webs to hold the inner sheets.
Worn nip rolls cannot bite into the paper and the circumference is decreased impairing effectiveness.
The nips should be adjusted so they have a firm grip of the webs. After the press is up to speed and running
well, the nip roller pressure can usually be relieved slightly.
GENERAL PRESS
1. Wrinkling and poor web steering is often caused by idler rolls that have become out of tram. If retramming is
necessary on a velcro covered roll be sure to gage to the steel roll surface and not to the velcro.
