Text 5 Gravure Printing in the Packaging

Vocabulary

horizontal web travel горизонтальна подача стрічки

coupling поєднання секцій

multi-web production друкування на кількох рулонах

inverted production line друкування у зворотньому порядку

hot air dryer гарячодувний сушильний пристрій

print line виробнича лінія, смуга друкарського контакту

to reroute перенаправляти

double-deck configuration двоярусна конфігурація

parallel configuration паралельна конфігурація

cross transfer поперечна подача

spot color друкування однією додатковою фарбою

in-line finishing unit секція поточної обробки задрукованої стрічки

plow folding фальцювання з розрізанням

punching проколювання

perforating перфорація

adhesive клейовий

arch-type printing unit аркоподібна секція (п’ятициліндрова)

four-high unit чотирициліндрова секція

slanting нахиляння

arch shape у формі арки, дуги

printing tower друкарська секція

slit щілина, поздовжнє розрізання стрічки

U-type printing unit U -подібна друкарська секція

H-type unit Н-подібна друкарська секція

4/4 print друк 4 на 4

Y-shaped printing units Y- подібна друкарська секція

overprinting послідовне задруковування

Gravure printing presses for package printing are equipped differently from those used in illustration printing. The main difference lies in the substrates and inks used, as well as in the finishing of the printed web.

In gravure package printing,both sheet-fed and web-fed presses are utilized. Sheet-fed gravure printing presses

have the advantage that shorter runs can also be produced economically, due to the more flexible and inepensive manufacture of gravure cylinders or gravure plates. Gravure printing, and especially web-fed gravure printing, is of particular interest for the printing of packaging material as it can process:

• various formats (repeat in a circumferential direction),

• a wide range of inks with the most diverse properties, such as non-toxic, odorless, sealing effect, or metallic glaze,

• cost-effective with long print runs.

Gravure printing enables high-quality and consistent reproduction of the finest photographic details in even the smallest of images on thin and flexible printing ma terial and a large number of multiple-ups on one gravure cylinder. Furthermore, this process achieves the highest, most constant and continuously reproducible print quality.Moreover, printing on both sides of the web can be carried out easily in one pass, even with an alternating number of colors. Webs printed in gravure printing can be finished immediately and long runs can almost always be printed with one set of gravure cylinders. Today, sheet-fed gravure printing only plays a minor role.Examples of sheet-fed gravure printing presses are Color-Palatia” and “Rembrandt” (KBA). Sheet-fed gravure presses for multicolor printing have a drying section after each printing unit. To achieve long enough drying times, long dryers are required. For presses with short distances between the printing units this has, for exemple, led to “tile-like” arrangements of the dryers.

Rotogravure (web-fed gravure) presses are usually economically more efficient than sheet-fed gravure presses due to the generally long print runs. Therefore, we shall concentrate on the topic of web-fed gravure printing.

A web-fed gravure printing press for package printing consists of an unwind unit, gravure printing units arranged successively, and a rewind unit. The simplistic equipment, in connection with a simpler construction of the printing units,made it possible for relatively small machine manufacturing companies to produce this type of machinery.As such, a range of companies came about (especially in Italy) that offered the established manufacturers of gravure

printing presses competition and even forced some of them to give up this branch of manufacture. Not until specialization into the high-quality printing of technically and particularly top-quality packaging material, such as cardboard and thin foil, could the long-standing companies assert themselves with special and sometimes patented press designs. Automatic in-line packaging production meant that in the construction of systems, gravure printing systems were almost forced into the background alongside special processing units, so that one could almost talk about a packaging machine with connected printing units.

Several gravure press manufacturers have developed machines on which thin, flexible polyethylene foil could be printed in good quality. For this, the existing press designs had to be overhauled and equipped with sensitive and precise web tension and measuring devices, DC-powered drawing devices, particularly smooth-running web guiding elements, completely new chill roller systems and modified non-stop unwinding and rewinding devices with DC drive engineering. Moreover, the entire drying system and the register control systems, had to be adapted and enhanced to meet the high demands.

Due to the increasing quality demands, seven or eight colors, and therefore the corresponding number of printing units, are required for more and more types of packaging. A varnishing and/or cold sealing application and possibly lamination must be carried out in-line; the installations, therefore, often consist of more than ten printing and finishing units. Today, such universal presses of modular design are almost always designed for printing packaging materials covering a broad market segment.

Дата добавления: 2014-12-23