Graphic Design & Printing TechnologyThe fibers are refined by a jordan machine which eliminates 99% water from
the pulp. The solution is pumped into a head box of the paper making machine.
Manufacturing paper using Fordrinier Paper Machine:- The pulp is evenly
dispersed on the fourdrinier wire mesh. The mesh vibrates as it travels along
an endless belt, aligning the fibers in the direction of travel. The alignment of
the fibers decides the grain direction of the paper. A continuous web of paper
is formed in this process. Gravity and suction remove about 35% of the water.
Watermarks can be given to paper at this stage with the help of dandy rollers.
Watermarks are transluscent identifying designs of symbols or images
impressed in the paper by rearranging the fibers.
Drying:- The web enters the press section as it leaves the wiremesh for removal
of more water. Then it passes through the dryer section consisting of
temperature controlled rollers thereby removing more moisture. Coatings are
applied to the paper at this stage.
Calendering is the process of flattening and smoothing the paper surface by
passing it between a series of rollers. Super calendering uses heated steel
rollers and pressure to form a very smooth, high gloss finish.
Rolling:- The untrimmed paper is wound into rolls. Some rolls are rewound,
slit and cut into lengths to make flat packages of paper.
Physical properties of paper
Grain direction:-The direction in which most of the cellulose fibers are aligned.
Paper that is cut into sheets with the fibers aligned parallel to the sheet’s longer
dimension is long grain. Paper with fibers that are aligned parallel to the
sheet’s shorter dimension is called short grain.
Dimensional stability:- Ability of the paper to retain its original length and
width when exposed to moisture.