Graphic Design & Printing TechnologyFlexo Makeready
Printing cylinders are completely round and are removable. After the plates
are mounted on to the cylinders, the cylinders are brought to the press in the
proper station. Required aniloxes are installed. Ink is fed in each station.
Press adjustments are made and the job begins to print. Registration is acheived
by moving cylinders into a timed position.
Flexographic ink & substrates
Flexographic inks used are more fluid and free flowing than lithographic inks
and are less viscous.
Three type of flexographic inks are widely used in the industry- alcohol based
inks, polyamide inks, and water based inks.
Alcohol based inks come in full range of dyes. Pigmented inks are also
available.
Polyamide inks are solvent type inks requiring alcohol and acetates to dissolve
their resins. They successfully print on any substrate including absorbent and
non absorbent plastics. Both alcohol based and polyamide inks emit Volatile
Organic Compound (VOC), which are toxic substance that evaporates into the
atmosphere, contributing to smog and causing health concerns.
Water based inks are more eco friendly but do not adhere to some substrate as
solvent inks.
Gravure Printing -Introduction
Gravure is an intaglio printing process in which the ink is transferred from a
sunken surface. Several important characteristics makes gravure an ideal process
for jobs requiring high quality and extremely long press runs. Currency notes,
postage stamps and stock certificates are some of the products printed by this
process.
Advantages and disadvantages
Main advantage of gravure process is its simplicity. Gravure presses can run
at high speed. It is a direct printing process that does not have to contend with
ink and water balance. Gravure is capable of consistent high quality
reproduction at a low cost on extremely long press runs. The long life of gravure
cylinder sustains high quality reproduction. Ink used for gravure printing dry
fast.
The main disadvantage of gravure is the length of time required to prepare the
printing cylinder. If an engraved cylinder is damaged during production the
entire cylinder or set of cylinders have to be re-engraved which is a costly
operation.