Wider colour space with multi-colour system

Project partners develop a license-free seven-colour MP-system

Colour is of elementary significance in branding. Therefore, manufacturers of branded goods attach great importance to well-defined colour reproduction with the widest possible colour range for packaging design. For that purpose, many systems with an extended colour space have been developed, for which licenses have been offered in the market under a variety of names for many years. Well-known examples are Hexachrome, Spotless, ederMCS, FMsix etc. These multi-colour systems normally use in addition to the four process colours (cyan, magenta, yellow and black) two or three additional colours (e.g. orange, green and purple) and mostly require adaptions in colour separation.

On the occasion of Labelexpo Europe 2013 in Brussels, a group of companies from the flexo printing industry presented a multi-colour system which is aligned with narrow-web printing and which can be used by printing operations without a license. The following four project partners had teamed up for a realization of this MP-colour system according to the motto „Teamwork for Success“:

• The anilox roller manufacturer Apex Europe B.V., AK Hapert, Netherlands,
• The repro company Athena Graphics NV, Roeselare, Belgium,
• The printing press manufacturer MPS Systems B.V., BA Didam, Netherlands, and
• The printing ink manufacturer Zeller+Gmelin GmbH & Co. KG, Eislingen, Germany. 

Prior to last year’s Labelexpo, the partners jointly developed the fictitious product „Fruit Berry“. The colouring of the four labels specially designed for this purpose, was deliberately chosen bearing in mind that they would require the use of special colours. By means of the newly created seven-colour MP-system, the labels with the four different designs (see figure) could be printed in UV-flexo in one pass with just one set of printing plates. The printed samples on Fasson material (AM932 Global MDO White; Liner: S7000 PET23) which were presented during the exhibition vividly demonstrated that with this system those critical colour shades could be achieved even without the use of special colours. The colour reproduction is equal to the traditional production method with special colours, as could also be demonstrated by a comparative print of the same labels in four colour printing with one special colour per motif. However, four separate print productions were required for the conventional production of the labels, in each of which an individual special colour from the Pantone Matching System (PMS) was used.

Compatible with digital toner printing

Due to its compatibility with digital printing the seven-colour MP-system offers the user another important advantage. This was achieved by an adaptation of the MP-system to the toner inks of the popular digital printing systems. For this purpose, the printing ink manufacturer Zeller+Gmelin has in the context of the project specifically developed a special ink series based on the UVAFLEX-series whose individual colours have been exactly adjusted to the process colours (CMYK) and the additional colours orange, green and purple of digital printing. The inks use as a basis the well-known mono-pigmented mixing system of Zeller+Gmelin which allows for particularly pure colours and an intensive colour reproduction in printing. Moreover they are available as a low-migration version.

With the new seven-colour MP-system, printers can spontaneously switch from digital printing to UV-flexo or UV-offset printing in case of longer print runs and thus take advantage of these conventional printing processes with respect to profitability and colour stability with increasing volumes of orders. A prerequisite is a certain standardization of individual process parameters. As a result, users benefit thanks to significantly lower downtimes. Because of the three additional colours, individual Pantone colours can be mixed already during the repro work, and thus the use of special colours including associated labour for changing colours and anilox rollers during printing can be eliminated. In addition to significantly saving time, the consumption of cleaning chemicals and the amount of ink residuals is reduced.

Coordinated production parameters

In addition to the UV-flexo printing inks even more parameters in the process chain have to be standardized in order to guarantee an accurate colour reproduction in day-to-day production. Here, the project partners from the fields of pre-press and repro as well as mechanical engineering and anilox rollers come into play. The company Athena contributed the design of the labels and the colour separation. The production was carried out on a flexo press of type MPS EF 410 at a printing speed of 120 m/min. For the use of the MP-system press models are recommended which feature a high level of automation and very good registration accuracy, promoted by precision servo drives. The quartet is completed by anilox rollers that for such a print performance ensure an ink transfer rate which is to be as accurate and constant as possible over the entire production. Anilox rollers from Apex were used for the printed samples. In the case of the four process colours anilox rollers with a screen of 405 l/cm and a pick-up volume between 3.5 and 4.5 cm3/m2 were used, for the additional colours (OGP) 265 l/cm and 5.0 cm3/m2.

Informative event being planned

The partners are currently planning a seminar, which will be held on 8th April, 2014 on the premises of the company Apex. It is aimed primarily at companies producing labels, tags or packaging on narrow-web UV-flexo or UV-offset printing machines. The seminar participants will be shown how the “Fruit Berry” project was developed and which prerequisites for the use of the MP-system are required. Furthermore, it will be explained in detail how the system can be integrated into the environment of a label or packaging printer. Some printing companies, who are interested in such an integration of the new multi-colour system, are currently already in contact with the repro company Athena Graphics.