About Flexo Printing Machines
During the earlier part of 20th century, letterpress machines were commonly used. However, these machines were not fit for printing on a large number of materials. As for materials printed on by the letterpress machines, the quality was very poor, with the constant occurrence of smearing of the printing ink all over the material. This led to the invention of this machinery, initially very rudimentary in quality, flexographic printing machines evolved majorly during the 1990's. Today these machines are the most favored by almost all industries.
Various Components of Flexographic Printing Machine:-
Working Process of these Machines:-
The flexo printing machinery has an an ink fountain which is basically a thin and volatile liquid stored in a ink pan. A fountain roller rotates in the ink pan and cyclically picks up a thick film of the aforementioned ink and transfers it to the metering roller. The metering roller is a chrome or ceramic covered roller whose surface contains small and engraved pits or cells.
The pressure between the fountain roller and the metering roller is set so as to enable the excess ink to pool up at the top. The difference in revolution speed of the two rollers ( the fountain roller revolves at a slower speed than the metering roller) causes a wiping effect on the metering roller. This ensures that only the ink stored in the engraved pits of metering roller is transferred on to the plates mounted on the plate cylinder for use in creating an impression of the required print.
The plates then pick up ink from the metering roller and transfer it to the printing unit for creating an image of the existing impression. This cycle is repeated again and again .
Types of Inks Used
Salient Features of Flexo Printing Machines
High speed belt feed, insertion of sheets without any crushing or marking.
Also allows for correction of the sheet edge position
A majority of these machines have an inbuilt sheet cleaner i.e- an electrostatic device with
suction that eliminates dust during sheet insertion
Fast printing speed, speeds of up to 600 meters per minute are possible on some machines
The machines are power efficient, have a long functional life and require little maintenance
These are resistant to moisture, UV rays and provide optimal performance in all weather
These are designed in such a way so as to ensure minimal ink wastage