Problem Summary
 
Fan out of the Newsprint web can best be defined as the dimensional change of the paper web in the cross direction, due to moisture absorption of the press fount during printing. The fan out phenomena is caused by the fibers of the paper swelling or hygroexpanding, resulting in the poor cross directional register of the printed colors, with associated increased wastage and inferior printed quality.

Time can also influence dimensional changes of the Newsprint. As the fountain water penetrates the Newsprint, the effect of the hygroexpansion is amplified on modern fast running 4-high tower presses (4X4 printing).  This is due to the fact that the printing couples are stacked one on top of the other allowing the CD expansion to occur between printing units. Clearly, it is the dampening water applied during printing that is the prime cause of fan out and it is the quantities used during 4X4 printing that makes Newsprint on these presses more susceptible.   Fortunately, this phenomenon is not so prevalent on satellite presses even when printing four color.

Recommended Solution

There are various possibilities available to reduce the affects of fan out.  Firstly, reducing press fountain water on press can help, although this may lead to more press stops to clean the printing blankets due to the piling of materials normally dispersed by the fount solution. Reducing press fount has the positive side-effect of lowering press tension due to reduced water penetration.  Increasing press speed may also help the fan out problem.  Although it has to be stressed, the press operator cannot control the cross directional misregister so easily. However, by imparting hydrophobicity with Aquapel® NP Sizing Technology it will contribute to smoother running, improved press stability, increased copy quality, reduced fan-out (and misregister) and therefore less wastage.

Key benefits of Aquapel® NP Sizing Technology are:

Reduced cross directional hygroexpansion
Reduced inter-color misregister
Improved pressroom stability
Assist with linting (depending on stock quality)
Reduced pressroom waste