To meet, all your printing needs
On the strength of its more than four decades of work in the field of flat sheet offset printing, with its avant-garde department,Graf3 S.r.l. can meet all its customers’ printing needs. Our next-generation printers and the extensive experience of our operators make for prime quality products.
The following is a brief description of the principles behind machine offset printing:
Litho-offset printing is an indirect (or offset) printing process. Its functioning is based on the fact that water and grease (i.e. inks) are mutually repellent. The ink is transferred to the ink mountain. It then proceeds to the grinding unit, with its many rollers of varying diameters (whose rotating action fluidities the ink).
Some rollers are also endowed with crosswise movement, ensuring uniform distribution of the ink on the plate. The plate is wrapped round a cylinder and is first processed by dampening rollers, followed by the inking rollers. The dampening rollers apply a thin coat of dampening water (generally a water and alcohol solution.
The inking rollers apply the ink. The inks (which are greasy) adhere only to the processed portion of the plate. Due to the water-repellence mechanism, the water (repelled by the greasy ink) does not moisten the images. The dampening water therefore provides precisely outlined images. There is of course no constant relation between the dampening water and the ink. Relations vary as a function of other parameters, such as transfer speed. The relation absolutely must be balanced.
Considerable skill is required to achieve this end. The plate then transfers the images to the rubber blanket, which receives the ink but not the water. The blanket transfers the printed elements to the sheet with the aid of the counter pressure cylinder. This method is also known as indirect (offset) printing.
The sheets are fed to the machine by means of a sheet feeder, featuring suction devices which raise the sheet, separate it from the underlying sheets, and place it on a slide.
The sheet position on the slide is ensured by a fence. This enables the pressure cylinder grips to take up the sheets always from the same position. This means the distances are kept uniform for all printed sheets (i.e. “register”).
Many of the operations of today’s machines are automated. These operations include paper and plate format changes, washing and adjustment of the inks by means of sophisticated control units.
When printed, the sheet is ready for later processes.
Once more, with its fully equipped internal binding department (for folding, cutting, stitching, perfuming, gluing etc.), Graf3 is in a position to meet all customer needs.
So what are you waiting for? Put us to the test!