Rotogravure Printing

ROTOGRAVURE PRINTING

It is also a contact process, in which the image is recessed either in the form of fine lines on cells. This procedure is used for longer runs, due to the cost of making the etched recessed printing surface on gravures cylinders.

This process most commonly used for printing on.

PARTS

Gravure Cylinder

Ink Fountain

Doctor Blade.

Impression Cylinder

GRAVURE CYLINDER

It is made from a steel

The cylinder is electroplated with a copper coating about 0.4mm thick, which is turn down to about 0.25mm thickness.

The copper surface is then engraved, so make image.

INK FOUNDATION

Ink foundation consist of ink which is to be printed on the substrates.

Mostly solvent based inks are used.

The common solvent used are

Hydrocarbon solvents like toluene and xylene

Esters like ethyl acetate and butyl acetate

Alcohols like ethyl alcohol and butyl alcohol.

DOCTOR BLADE

It use the cylinder surface clean., leaving the cells only.

It is made up of blue spring steel backed by 0.25 mm thick steel blade,

The thinner blade produce lighter print, heaven blade process danker print.

IMPRESSION ROLL

This is rubber covered steel roll which contains the plastic films which is to be printed contact with the printing cylinder.

COMPARISON BETWEEN ROTO GRAVURE AND FLEXOGRAPHY PRINTING

ROTO GRAVURE

1. Gravure printing is based on intaglio process of transferring ink from recessed cells of an engraved cylinder.

2. Gravure cylinders are made with metal.

3. Cylinders are high cost.

4. Cylinders are always in contact with

paint.

5. Doctor blade is required to remove the

excess color from the metal cylinders.

6. Preferred for long runs.

7. Printing quality is same even after a

large number of prints.

8. Prints cost, quality and availability more.

9. Lamination is possible.

10. Multi colour is possible.

11. Usually six-station machines are used for multi color printing.

12. Printing is possible only on flexible films.

FLEX GRAPHY

1. Flexography is a variation of the letter

press printing process in which ink is carried on the raised portion of an engraved plate.

2. Engraved plates are made with weld of rubber or photo polymers.

3. Engraved plates are low cost.

4. Paint is transferred to engraved plates

through a series of rollers.

5. Doctor blades is not required.

6. Preferred for short runs.

7. Print quality changes with number of

prints.

8. Print quality changes with the number of prints and cost is comparative low.

9. Lamination is not possible.

10. Multi colour is possible.

11. Here also 6-station machines are used for multi colour printing.

12. Printing is possible on both flexible films and blow molding containers.