Narrow web multi-process printing & converting process

BOBST provides a wide range of solutions for the labels and packaging industry. UV flexo-, offset-, gravure-, screen- & digital multi-process printing units, with digital automation, tension and temperature control and added value converting offer exclusive solutions and best value for quality and innovation.

All lines include servo driven rewind shaft, touch screen panel on each print unit, main touch screen with PC operated HMI, remote internet full service & organizer for lean handling and storage of magnetic cylinders.

BOBST narrow web printing & converting machines (formerly GIDUE) are designed for the longest durability and reliability. They are equipped with best internationally available components, assisted by the BOBST international local service support. BOBST printing & converting machines for narrow web are in perfect production conditions after many years, with low maintenance costs, consistent quality, and great satisfaction of converters. These presses and converters are winning each year Print Quality Awards worldwide. BOBST quality is built to last.

Narrow- & mid-web multi-process printing & converting process

The "in-line" flexo printing and rotary die-cutting process is the combination in one pass to convert a material delivering different packaging solutions (PS Labels, wrap-around labels, sleeves, flexible packaging, light carton boxes, aluminium, lamitube).

Unwind, printing, slitting, die-cutting and rewind

Constant web tension is critical for good register and web handling into the press.
The un-winder is controlled by a braking system, or by a servo motor, that is driven by a dancer assembly which guarantees the constant tow during this process. The web goes first in the web-guide device to be aligned and then, after the dancer assembly, goes to the infeed unit which, together with the outfeed, controls tension and tow along the machine.

The web is printed in between the infeed and outfeed units with the appropriate drying system or UV (ultra-violet) or IR (infra-red) plus hot air. The number of colour stations depends on the requested configuration, from 1 to 12. The printed web goes through the die-cutting section, which can be also configured to suit customer’s requirements, from a minimum of 3 (standard) to a maximum of 5, where the material is die-cut front and/or back and the eventual waste is stripped and re-winded or exhausted by the suction system.

Flexographic printing units

In a modern flexographic press, each print unit when ready to print consists of the following elements:

  • Printing cylinder
  • Plate
  • Impression cylinder
  • Anilox roller
  • Rubber roll
  • Doctor blade
  • Ink tray
  • Manual register: longitudinal and transversal
  • Dryers on each printing station (UV, Hot Air, IR).

Process description

During the printing process, the inking roll transport the ink to the anilox rollers. As the anilox roller rotates, the cells in contact with the roller collect ink, then any surface excess is removed as the roller passes under the doctor blade.

As the anilox rotates, its surface comes into contact with the raised areas of the printing plates mounted on the plate cylinder, transferring the ink. The printing plate then rotates and transfers the image onto the substrate.

Process advantages

Carrying out flexo printing and rotary die-cutting inline produces complex packaging in a single pass and at high quality.