Core Components of Rotogravure Printing Machine
-
Engraved Cylinder
-
Impression Cylinder
-
Ink Foundation
-
doctor Blade Assembly
-
Dryer
1. Engraved Cylinder
Engraved Cylinder is the image carrier of the Rotogravure printing process. This cylinder is make up of basically steel hollow cylinders.
Having electroplate by Nickel and then electroplated by copper on it. To secure image cells from damage by doctor blade lastly it coated by Chromium layer.
Nowadays there are three types of Cylinders Engraving Methods
-
Laser Engraving
-
Chemical Etching
-
Diamond Stylus Engraving
Laser Engraving
Nowadays rotogravure printing press makes use of a printing cylinder that laser engraves with minute cells able to retain ink, the size, and pattern of which mirror the required image.
These cells are enforced to move their ink directly onto the substance by a fusion of pressure and capillary action, so manufacture the printed image.
Chemical Etching
In this process, a negative film is applied to a non-image area called a resist. Because it resists the chemical to go into non-image areas during etching.
2. Impression roller
A rubber enfolds sleeve that is set up on a steel mandrel.
Its primary intention is to press the substance as opposed to the printing cylinder.
Inking system: consisting of an ink pen, ink holding tank, and ink pump with supply and return ink pipes.
3. Ink Foundation
There are two types of Ink used in printing.
Solvent-Based Ink
Gravure inks are fluid inks along with a very less viscocity that grant them to get into the engraved cells in the cylinder then shift onto the substance.
In sequence to dry the ink and drive off the solvents, which typically replaces most of the solvent, the paper is run over Gas fired or electric-fired driers.
The ink will dry in advance before the paper moves to the next printing station on the press.
This is mandatory because wet inks cannot be overprinted without smearing and smudging.
Hence, high-volume air dryers are set down after each printing station.
From the dryers, the solvent-laden air is go through either a solvent recovery system or solvent vapor incinerator.
A standard recovery system uses beds of activated carbon to soak up the solvent.
Saturate bed is revived by steam. The solvent-laden steam is then deliquescing and the water and solvent are segregated by gravity.
Greater than 95 percent of the ink solvents can retrieve using this procedure. The solvents can either reprocess or demolished by incineration.
Water-Based Ink
Water-based inks, particularly used for packaging and product gravure, need a higher temperature and longer drier disclosure time in order to drive off the water and lower vapor pressure constituents.
As stated, following segment. Flexo and Gravure inks are very common and the constituents are mainly the carbon copy. Again, a pollution control device may require.
4. Doctor Blade
The device separates ink from the non-engraved section of the printing cylinder and also separates excess ink from the engraved segment.
5. Drying system
Containing a chamber that dries the ink once it is on the substance and previous to it reaching the following printing unit.
Drier abilities are determined based on the needed printing speed, ink type solvent or water-based, and ink set down the volume.
