The ink on the paper must be dry before it
comes into contact with the next sheet, so choosing the right ink is very
important of book printing. The
following factors should be taken into account to control reverse printing:
1. Type of printing ink used; 2.
Printing speed; 3. The distance between the printing press and the
stack; 4. The extrusion produced when the printed paper is piled
up; 5. Absorbability of paper; 6. Spray type used.
Paper ink absorption on the back of a great
impact. Choosing the right paper will reduce the disadvantages of back
printing and ink sticking. Because the paper surface absorption variation
is very large, so printing ink also want to make a good choice. It is best
to send the printing paper to the ink supplier to help select the most suitable
curing ink. If the number of trials is small, the results are not very
accurate. Experienced printing houses will have an advantage in choosing
paper and ink.
Back printing ink shortcomings can be found
in the early printing, once found should be dealt with in time. If the
sheet has been printed more than once, a very small amount of powder can be
sprayed on the paper before printing properly to prevent back
printing. Otherwise, the powder will be transferred to the rubber cylinder
and affect the book printing quality. The
static electricity generated by paper printing will also increase the
appearance of back printing. Static electricity causes the sheets of paper
in the collection pile to accumulate and causes the separate air cushion
maintained between the sheets to be quickly extruded. Static problems
occur when the relative humidity of the printing room is below
35%R.H. Humidification and electrostatic neutralization can reduce the
static problems of the printing press. The use of higher printing
concentration of ink, with less moisture can improve the surface smoothness of
the ink layer, so as to reduce the occurrence of back printing.