Топик По Английскому Языку (Воронов Р. И.) / Gravure

Gravure

Gravure is one of conventional printing processes. Its beginnings date back to the early 15th
century when the first engraved copperplate impressions appeared.
The distinctive feature of gravure printing technology is the fact that the image elements are
engraved into the surface of the cylinder. The non-image areas are at a constant level.
Gravure printing unit consists of a plate cylinder, an impression cylinder and an inking system.
Ink is applied to the plate cylinder which rotates in a bath of ink. Gravure image areas are cells
or wells etched or engraved into a copper cylinder, and unetched surface of a cylinder represents
the non-printing areas. Prior to printing, the entire printing plate (non-printing and printing elements)
is inked. Ink excess is removed by a doctor blade and returned to the ink fountain before printing,
so that ink remains only in the cells. The impression cylinder presses the paper into contact with the
ink in the tiny cells of the printing surface. So the image is formed by direct transfer of the ink to
the paper as it passes between the plate cylinder and the impression cylinder.
Gravure printing requires a liquid ink, which can fill the cells of the gravure cylinder at high print
speed. So inks use volatile petroleum solvents and dry almost instantly. Hot air dryers are used between
printing units to speed up drying. As gravure printing is an intaglio process the cells of the printing
plate can have various width, depth and volume.Plate cylinders are chromium-plated for press runs of
one million or more. When the chromium starts to wear, it`s stripped off and the cylinder is rechromed.
There are 3 types of processes used for making gravure plate cylinders: chemical etching, electromechanical
engraving and digital laser etching. Gravure differs from other processes in that it`s capable of printing
varying amounts and densities of ink to produce images that simulate continuous-tone images.
Gravure is used for printing high-quality newspapers, magazines, catalogs, special products like wallpaper
and packaging.