MD. Mofakharul Islam Instructor (tech) & Head of the department Printing.

Intaglio Printing  The word intaglio is Italian, from a compound word meaning “engraved” on “cut in” Italians and fine artists pronounce this word “in-tal-yo” while most printers and engravers it with a hard “g” as “in-tag- lyo” Intaglio refers to a consists of lines on dots recessed below the surface. The first intaglio plate engraved on metal was used for printing in Germany in 1446.AD.

Historical Background  Italian Renaissance 1300’s.  Engravings and etching into soft copper.  A channel or sunken area is left, this holds the ink.  Intaglio is the term used to describe gravure printing (Italian for printing in a sunken surface)

Classification of Intaglio Printing Intaglio printing is divided into three kinds.  Fine arts intaglio.  Steel die engraving & bank note printing.  Sheet fed & roll fed gravure.

Distinctive characteristics of gravure Three Distinctive characteristics of gravure:  That all gravure copy reading matter as well as pictures must be screened.  The use of doctor blade and  That gravure is capable of reproducing tonal values in three ways.

“Roto” Gravure  Roto means Round.  Term used for Industrial Intaglio.  Roto Gravure is printing from a cylinder.  Web Fed  Slitter ( devise used to cut sheets at the end of of the press)

The Gravure Press and its components. All web-fed gravure presses start from an un winder, which serves the purpose of unwinding a roll of substrate, keeping adequate tension on the web. The printing unit, the heart of gravure press, consists of the following components, regardless of the application:  The image carrier, a cylinder engraved with the image to be printed or transferred.  An ink fountain, a large ink well positioned beneath the cylinder, extending the width of the press unit.

 A doctor blade assembly containing a blade which wipes excess ink from the non-image areas of the image carrier.  An impression roller, a rubber-covered metal cylinder which holds the substrate against the engraved image carrier to obtain proper ink transfer.  A dryer, consisting of a control source of heated air, regulated to provide optimum drying of inks or coatings and remove ink carrier vapors. The limited number of major press components and their physical simplicity makes gravure easy to automate, simple to operate, readily adaptable for additional in-line converting operations.

Advantages of Gravure Printing The rotogravure printing process is the most popular printing process used in flexible-packaging manufacturing, because of its ability to print on thin film such as polyester, OPP, nylon, and PE, which come in a wide range of thicknesses, commonly 10 to 30 micrometers. Other appreciated features include:  printing cylinders that can last through large-volume runs without the image degrading.  good quality image reproduction.  low per-unit costs running high volume production.

Disadvantages of Gravure Printing Shortcomings of the gravure printing process include:  high start-up costs  hundreds of thousands of copies needed to make it profitable.  rasterized lines and texts.

Function of Gravure Impression Roller A gravure impression roller is a friction-driven rubber covered metal cylinder that squeezes the substrate against an inked engraved cylinder to transfer a measured amount of ink. The primary functions of the impression roller are -  To obtain proper ink transfer.  To set the web tension pattern between press units.  To propel the web through the press.

Function of impression roller

Gravure Industry  Simplest of all printing systems.  Fastest press start up.  Very little paper waste (half the paper waste of lithography).  Speed is extremely high.  45,000 copies an hour.

Gravure Industry (continued)  Some run 20 million copies without cylinder wearing out.  Highest quality image.

Industry Organization  3 types of printing Packaging Printing Publication Printing Special Printing

Packaging Printing  This includes producing and folding. Cartons Boxes Bags Gift wrappers Labels

Publication Printing  This includes Printing Newspaper Supplements Magazines Catalogs Mass Mailing Advertisements

Special Printing  Used to Print such materials as Wallpaper Vinyl Floor covering Textiles (decoration and clothing)

Facilities of modern gravure printing  Modern gravure presses are equipped with many levels of automation-including programmable control of all press sequences-and digital drives integrated press management systems monitor, control and report:  Fault detection, including on-line video monitoring.  Preset of job variables.  Production statistics.  Ink consumption data analysis.  Paper consumption data analysis.  Waste analysis. In many recently delivered presses, the conventional press main consoles are replaced by computerized controls where video displays permit control of the press by means of touch screens or keyboard.

Types of Cylinders Two forms of Cylinders  Mandrel (removable shaft).  Integral (shaft mounted permanently) $$$$.

Copper plating gravure cylinder

Engraving Method of cylinder

Methods of Cylinder Engraving

Cylinder Construction  Most cylinder cores are made of steel.  Some companies prefer aluminum. Lighter. Less expensive. Easier to ship.

Cylinder Design  Axis (center line of shaft).  Shaft (what the cylinder spins on).  Diameter.  Circumference (one impression).  Face Length (printing width).

Raw materials of gravure printing  PET film.  MPET film.  BOPP film.  MBOPP film.  HDEP film.  Pearlised BOPP film.  PVC heat shrink film.  AL-foil.  Offset paper 70 & 80 Gsm.  Yellow base paper.  white base paper.  Adhesive.