Rapida 106 with sensible automation modules
In November 2011 a five-colour KBA Rapida 106 with coater replaced a competitor’s press. The VariDry high-performance dryer in the extended delivery can be equipped with UV radiators on occasions when using UV inks. A DriveTronic Feeder with maximum preset capabilities and a DriveTronic SIS sidelay-free sheet infeed support substrate flexibility. Given the high circulation of mailings, Melter Druck opted for an auto-matic plate changer, instead of the DriveTronic SPC simultaneous plate changer with individual drives.
Quality assurance is of utmost importance to the PSO-accredited print shop, which made Klaus-Dieter Marquart opt for KBA QualiTronic Color Control with Instrument Flight software by System Brunner. “Following our positive experience with web offset, there was no doubt that we wanted to have Instrument Flight in our Rapida”, says Marquart. “Instru-ment Flight can handle the range of substrates we use and their print properties. The substrates’ sensitive dot gain only stabilises one grey balance control, which optimally reacts to the changes in the use of fount solution and inks, so that even a trained eye hardly notices the deviations in the process.”
System Brunner recently created a “substrate library”, in which the print-ers can store the substrate - ink combinations as self-defined calibration data. If the substrate is used in a follow-up order again, the corresponding calibration data can be retrieved and the inline colour-measurement camera immediately obtains the extensively calibrated measurement readings.
Identical philosophy –differently implemented
Instrument Flight’s philosophy of inline colour measurement and control is the same in sheetfed offset as in web offset, however the Rapida’s technology demands a different solution. The most obvious difference is in the type of measuring system: in web offset the inline densitometer or spectrophotometer obtains complete colorimetric data, whereas in sheetfed offset QualiTronic Color Control’s colour-measuring camera has to be externally spectrophotometrically calibrated in order to achieve maximum measuring and control quality. The Rapida’s colour-measuring camera demands somewhat larger measuring patches for the colour control strips compared to heatset.
A further difference is that in web offset measuring takes place after the flotation dryer, but in sheetfed offset it takes place before the end dryer on a wet copy. Therefore the so-called drying drift in the density and CIELAB values must be taken into account by Instrument Flight in the Rapida.
Seeing as powder in used in sheetfed printing, in straight-on presses the powder from the front page can build up when perfecting. The press appears to then print somewhat “sharper” which is why both the printer and the colour control system would be inclined to increase the density more than is necessary. To combat this System Brunner has therefore developed an additional algorithm which prevents over inking and never-theless keeps the overall result in balance.
Printers who, like Klaus-Dieter Marquart, are aware of and value these important details will share his opinion that “With the optional extra In-strument Flight for the Rapida, KBA offers superior technology.”