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Launched in 2001, the Presstek 46 Karat waterless direct imaging press has gone through a number of identities. Originally licensed as the KBA 46 Karat, from 2003 it was sold through AB Dick in the UK before Presstek bought the company in 2004, effectively taking back its own press.

In 2006 we decided to re-brand the wider Presstek range, says Ray Hillhouse, sales and operations director, at Presstek Europe. The machine became the 34DI while the 52DI, a 52cm version, was added at Ipex 2006.

It was targeted at digital printers looking to produce high-quality offset work, as well as traditional offset printers who would otherwise not have been able to compete for shorter-run work. It’s been recently adopted by franchise and copy shop printers such as Prontaprint, adds Hillhouse.

There were three models: the standard 34DI, the DI-E entry-level version and the higher-end fully featured D1-X. Using patented Presstek Direct Imaging (DI) technology, the waterless digital offset-press is specifically designed for short-run colour print, and there have been around 100 installations in the UK.

With environmental awareness being a hot topic, one of the benefits of the alcohol-free press is that plates are processed without any chemicals. In 2006, the plate material the unit used changed from PearlDry to ProFire Digital Media, boosting its quality up from 200 lines per inch (lpi) to 300lpi.

The key advantage of the re-engineered imaging head was that it produced a spot size of 16 microns, which meant that stochastic screening was possible. The lasers also benefitted from increased stability and service life. As with all technology, since its launch there have been several firmware upgrades, but these can be retrofitted to older 34DIs.

Reel to reel
Plates are automatically supplied from a roll held in the plate cylinder, while used plate material is wound onto a second spool within the cylinder. A plate cylinder washing system removes the non-imaged area of the plate after imaging using vacuum extraction. A dry friction roller is also incorporated. The service life of the plates is calculated at around 20,000 impressions.

Overall, the machine can achieve speeds up to 7,000sph. Along with automatic plate cleaning, the press also has integrated automatic washing facilities for the blankets and ink rollers so that complete job changes can be achieved in just under 10 minutes.

It is not possible to retrofit a 46 Karat as a 34DI as the current platform has been developed differently, but Presstek runs a refurbishment programme so users can trade in their machine for a new 52DI; the manufacturer will rebuild older machines and sell them back onto the market.

A new 34DI starts from £170,000 to £210,000. Depending on the age and impression count, a four- to five-year-old 46 would sell for £100,000. We assess each one independently before we put a price, says Hillhouse. He advices customers to check the cleanliness of the machine as this will affect the image quality.

http://www.printweek.com/news/652081/46-Karat/