New potential for flexible packaging printers has opened up with Muller Martini claiming this week that high costs associated with a wide range of sizes are now a thing of the past for web offset printing.
Muller Martini says that the print length of its Allprinta V web offset press can be changed as required, simply by replacing the plate cylinder and blanket cylinder, accomplished without the use tools.
The company said up to now the printing of flexible packaging was restricted to the established processes flexo and gravure printing. However highlighting the capabilities of its infinitely variable size web offset printer Alprinter V Martini said printers now have an alternative.
Muller Martini product and marketing manager, Bernd Schopferer says infinitely variable size web offset printing now meets the requirements for printing packaging, which included low cost printing methods, rapid manufacture, a high level of standardisation whilst avoiding high levels of volatile organic compounds as well as short machine make-ready times.
He says "The manufacturers' declared goal is that it must be possible to produce flexible packaging in a wide range of print lengths at a reasonable cost. This is why up to now the established processes, flexo and gravure printing, have dominated this area. The positive drive and therefore also the realization of infinitely variable size lengths are now standard features with package printing machines."
He also said that printing with the infinitely variable size web offset method created fast and easy production of the printing methods permits response times that were not currently available with flexo and gravure printing.
Make-ready times were also short thanks in part to the uncomplicated size change, as neither assembly nor disassembly of the printing plate nor a handling system nor storage for heavy cylinders was required.
Schopferer says "Once the image has been output to the offset printing plates, they are immediately available for the production process. The set-up times are very short, providing flexibility in job processing and ensuring high productivity,"
"The use of UV or electron beam cured inks means that there is no cost involved in complying with extensive environmental requirements. There is no waste ink, nor is there any need to provide large amounts of storage space for ink as well as no need to budget time for the mounting of printing plates."
While clearly in favor of the emerging process Muller Martini recognised limitations of infinitely variable size web offset printing, which does not offer "off-the-rack solutions".
Other potential set backs include that drawing up the correct machine specifications requires a great deal of communication between all those involved, as there is not yet a large base of user knowledge. In most cases, another printing process in addition to offset is used in line for opaque white, varnishing and decorative inks.
Schopferer says, "For those who use it, this makes web offset a more ambitious undertaking. There are also system-related limitations regarding the substrates that can be printed on. The tendency of certain materials to stretch requires special knowledge of the process."
