A Eccentricum label showing fine detail and screen-printed piercing eyes
Codimag, the French press manufacturer, has developed a hybrid process, called Aniflo, which combines the quality of offset with the simplicity and reliability of flexo and also offers the advantage of a digitised prepress workflow with short set-up times. Additionally, high-value finishing options can be included inline, with automated controls ensuring smooth production. The result is an efficient process for competing in short and medium run label markets.
by Pierre Panel
An Aniflo unit uses viscous, paste-like waterless offset inks and requires four cylinders in the ink train: the anilox roll delivers a constant film of ink to a forme rubber roller, which in turn delivers ink to the plate and on to the blanket. Each cylinder has the same diameter. This ensures inking consistency across and along the web: an exact, controllable amount of ink is delivered to the plate and substrate across the web, so exact colour is achieved on every label in the run.
In the Aniflo printing unit, ink is transferred to the anilox from an open chamber, with two blades – one to doctor the ink, the other to prevent leakage. The anilox roll features specially engraved cells that are designed to work with waterless offset paste ink. Its cell structure is specially adapted for the highly viscous nature of the ink, and fine, precision engraving enables high resolution to match the quality of offset. There are four standard anilox roll types, each accommodating varying ink volumes (small, medium, large, XL), to cover a range of lightness levels. The anilox sleeve can be dismounted and exchanged easily.
Especially for printers with flexo background the process requires a relatively low skills investment. The high degree of automation and low number of moving parts mean that manual intervention during the printing run is restricted to temperature control.
A proprietary heat control system allows the operator to vary the temperature of the anilox roll and therefore, the amount of ink delivered. Ink viscosity reduces with heat: cooler temperatures thin the ink, lowering the colour density, while higher temperatures result in thickened ink and increased colour density. A further advantage of the system is the short inking path. Waterless offset inks are now available that are compatible with LED-UV curing lights.
Aniflo is based on semi-rotary technology, a process that allows the same cylinders to be used for a range of repeat sizes. Due to semi-rotary printing, if the format changes from one job to the next, the only part to exchange is the plate. The web motion is driven by motors, drives and computer, while an infeed, outfeed and two dancer systems position the web on the press.
When the image is applied, the web runs at the same speed as the printing cylinders. Once the image is applied, the web decelerates, reverses and accelerates again, so the following image can be applied. The printing cylinder circumference is larger than the maximum format, so a gap can be created that allows a smooth reverse web motion. Format sizes between 50 mm (1.96”) and 305 mm (12”) can be specified in increments of 0.01 mm (0.00039”).
PDF to print
With the digital workflow, it is possible to go from the PDF to a printed result in less than 30 minutes. Using offset plates makes it economical for more businesses to bring the prepress workflow completely in-house. High-definition plates can be imaged within three minutes, with conventional offset computer-to-plate systems. In addition, chemistry-free plates from different suppliers are available.
Aniflo uses the same colour management software as most digital printing systems. An important philosophy of Aniflo technology is “Extended Gamut Printing”. This is the equivalent of digital printing, with a fixed palette of between four and seven colours. Instead of being mixed in an ink kitchen, the inks are digitally pre-mixed on the press. A proofing profile from the fingerprint of the press is created. This provides an accurate match of most brand and Pantone colours. Other cost-saving consequences arising from this are the avoidance of managing press-return inks, lower inventory costs by not storing spot inks and reduced material waste due to consistent colour consistency.
Aniflo technology comes with Esko Equinox colour software which converts colours in the packaging to the standard CMYK plus orange, green and either violet or blue. This combination covers up to 90% of the Pantone colour range. Using CMYK alone, up to two-thirds of the colour gamut can be achieved. Tools in the software allow the operator to see the colour build up with expected DeltaE results. A maximum of three inks are used to build colours and achieve accurate registration. In addition, it is essential to use a calibrated colour-testing system to simulate the printing of a label on the specific press designated for the job in question.
The latest presses offer the option to include added-value finishing processes in-line, like rotary and flat-bed hot foil stamping, flat-bed embossing, and semi-rotary screen printing and inkjet printing. If required, a screen printing unit in the first stage of the sequence can be added for printing opaque white. This makes it possible for label converters to configure the press according to their markets, and add shelf-appeal with metallic, tactile and varnish effects, in the same pass.
A dancer system, infeed and outfeed ensure controlled web motion when it is fed from semi-rotary or flat-bed processes to the rewinder. The dancer can rise or fall around its mid-point to compensate for speed differences between the previous print process and the rewinder, and communicate differences to the press controls. Use of the dancer also makes a shorter matrix-path to the rewinder possible, reducing the risk of web-breaks.
When it comes to deciding printing width, or whether to go for inline or near-line finishing, there are a number of factors to take into consideration. Aniflo technology is available in 340 mm (13.38”) or 420 mm (16.53”) widths. The wider option, with 19” cylinders, provides the solution for highest productivity, with speeds of up to 60 m/min (196 fpm) and 1500 m2/h.
An inline configuration makes sense to finish labels especially when converting high-value labels like wine labels. For example, a label printer using Aniflo technology in Chile has a press with inline finishing for producing labels for a large Chilean wine brand owner.
For converters with more diverse output, say a mix of wine labels and other fast-moving consumer goods, then a near-line configuration might make better economic sense, to maximise equipment utilisation. This is also true for converters with multiple presses, including digital. While the newer, larger digital presses can use inline finishing effectively, in many cases, the finishing lines are capable of running much faster than the presses, so one near-line system can be fed by more than one press.
New software features allow connectivity with other elements in the IT environment such as the prepress and ERP systems.
Delivering print quality in terms of colour accuracy, resolution and registration, as efficiently and as fast as possible, is an overriding concern for today’s printer, especially when contending with price pressure and demands for shorter production runs. Switching to a new printing technology may seem daunting, but a hybrid process like Aniflo could offer a design, workflow and supporting software that allows printers with no experience in offset to get precise results and compete for short and medium run jobs.