Page 17 - May 2015
P. 17

17

                                                  Öٮđ®Ö½›Ý
                                                  Flexography is primarily a package prinƟng
                                                  method. It is based on a combinaƟon of
                                                  relief rubber plates, solvent evaporaƟng
                                                  inks and web prinƟng. The rubber plates can
                                                  be original engravings, although in pracƟce
                                                  they are invariably duplicate plates made
                                                  by the moulding and re-moulding of relief
                                                  materials consisƟng of type and original

PRINTING PROCE SSES

ƒ‘» ãÊ ¥ÙÊÄã                                     photo-engravings. Rubber plates, unlike the
The number of prinƟng processes in use today      tradiƟonal metallic image carriers, are flexible
is really quite amazing; some of them are very    and, to a certain extent, porous: flexibility
sophisƟcated—and expensive! In compiling          permits their easy employment on rotary
this series I was tempted to start in the         presses without special preparaƟon; porosity
convenƟonal way by explaining the whys and        permits the use of extremely fluid inks, which
wherefores of leƩerpress prinƟng and then         require only a simple inking system and are
working 'downwards' from there. But as most       eminently suitable for prinƟng on plasƟcs.
readers have a working knowledge of either
leƩerpress or offset-litho, I have decided to      ÖÙʗç‘ãÝ
work in the opposite direcƟon; to start with      Flexography, as menƟoned earlier, is
the lessier known processes and round off the      employed mainly in packaging industries.
series with the daddy of 'em all.                 Its main products are, therefore, strawboard
                                                  containers, cereal packets, etc., and
¥½›øʦك֫ù                                       cellophane and other clear and opaque plasƟc
In common with most other prinƟng methods         covering materials.
in their early stages, flexography passed
through an iniƟal development period in               ã«®Ý ƒÙ㮑½› óƒÝ ¥®ÙÝã Ö琽®Ý«›— ®Ä Ýý½
which its results were rather crude.                  ÖÙ®Äã›Ù ÄÊ.ϔϐ, ¥›ÙçƒÙù Ϗϗϕώ ƒÄ— óÙ®ãã›Ä ù Ý.
                                                      ¹. «ÊçÙÝãÊÄ, 㛑«Ä®‘ƒ½ ›—®ãÊÙ.
   In the beginning flexography was known
as aniline prinƟng; this name was, of course,
derived from the aniline dyes which were
then used exclusively as ink colourants in
theprocess. Aniline dyes have the advantage
of possessing very intense and brilliant colours
with the disadvantage that they are invariably
fugiƟve, and therefore useless for many
purposes. As the process matured it became
more refined and the fugiƟve dyes became
replaced by more lighƞast pigments.
In 1952, the industry, on a recommendaƟon
from the Packaging InsƟtute, adopted the
specially coined term flexography.
   12   13   14   15   16   17   18   19   20   21   22