Rotogravure printing is simply a type of intaglio printing process which involves rotary printing press. In this method, an image is engraved onto a copper plated steel cylinder base.
The initial step is to create a cylinder with an engraved image for each color to make up the design. The cells contained ink will be created on the cylinder surface in order to transfer it to the substrate (foil, film or paper) during the engraving process. The dimensions of the cells must be carefully set because the amount of ink contained in the cells corresponds to different color intensities on the substrate. Deeper cells will produce more intensive colors whereas less deep cells will produce less intensive ones.
The ink starts to draws out of the fountain when cylinder begins to rotate. Acting as a squeegee, the doctor blade scrapes the cylinder before it makes contact with the substrate, removing excess ink from the non-printing (non-recessed) areas and leaving in the cells the right amount of ink required: the location of this tool is quite close to the substrate so that the ink left in the cells does not have enough time to dry.
Next, the impression roller and the gravure cylinder sandwiched the substrate between them: during this step the ink is transferred from the recessed cells to the substrate. In actual, the impression roller applies force, pressing the substrate onto the gravure cylinder, ensuring even and maximum coverage of the ink.
The pressure from impression rollers and capillary action of the substrate force the ink out of the cell cavity and place it to the substrate. After that, the substrate moves through a dryer so it can be dry before going through the next color unit and absorbing another coat of ink.