KBA's Own Infrared-Thermal Air Dryers Available

KBA is now offering a complete range of in-house developed infrared - thermal air, and UV dryers for its medium-format Rapida 105 press - the Varidry system.

The company added that it is planning to expand the range of dryers for all other Rapida models.

KBA said that the flexibility afforded by the Varidry system will be enhanced still further by new, complete drying units.

Pure infra-red (IR) - thermal air (TA) and UV modules are already in operation along with quick-change units in which an IR module with three emitters can be exchanged for a UV module.

Since the drying elements in the drying unit can be increased by adding interdeck UV dryers , the production options are virtually unlimited.

As an option, or in the press formats for which Varidry is not yet available, KBA will continue to offer familiar and products from other manufacturers, such as Grafix and IST Metz, for instance.

A double extended delivery for a Rapida 105 can accommodate up to 18 infrared and thermal air drying modules in a ratio of seven to 11.

Within the drying section the modules can be positioned freely according to production requirements, affording flexibility in how the sheets are dried, said KBA.

For perfect printing, or work and turn, there are optimised hot-air knives that allow coatings to be dried with the maximum possible air volume with no reduction in production speed, added the company.

The IR emitters routinely used in the Varidry system are Heraeus's twin-tube carbon infrared (CIR) emitters with an intensity of 60W per centimetre (152W per inch).

The spectrum of CIR emitters coincides more closely with the absorption curve for water than does the spectrum of other shortwave (SIR) or fast medium-wave (FMIR) emitters.

As a result CIR emitters function more effectively at a very low temperature, it is claimed.

IR modules and hot-air knives can be removed from their slip-in ports without using tools, which provides faster, simpler servicing and maintenance work, it is said.

If an IR emitter needs to be changed it can be removed from the press by unscrewing two screws and pulling the emitter out of the module.

According to KBA, plug-in connections mean that anyone can make the change without specialised knowledge.

For special applications it is possible to use fast medium-wave twin-tube emitters, or hybrid emitters (twin-tube emitters with one carbon and one short-wave component).

Sheet travel can be monitored at any time through inspection windows in the swan neck and the extended delivery.

The company said that the intensity of the IR emitters is regulated by measuring the temperature of the pile and adjusting the emitter temperature accordingly.

To facilitate monitoring the relevant parameters are displayed at the console.

The UV modules for inter-deck and end-of-press dryers have the same dimensions as the IR - TA modules and can therefore also be positioned freely within the press.

Standard modules have a claimed intensity of 160W per centimetre (406W per inch) with other power levels available upon demand.

The modules are fitted with dichroic mirrors, which reflect all the UV radiation whilst absorbing most of the heat.

The mirrors have a reflective surface coating more than 70 layers thick, which simultaneously maximises both UV radiation and heat dissipation via the dryer's cooling system, added the company.

KBA said that UV lamps can be changed quickly and easily as KBA's IR - TA emitters without special prior knowledge.

A media plug contains all the relevant connections, so there is no need to disconnect and reconnect cables.

The media plug contains a high-tension connection for module selection control, control voltage for the interrogation signal and shutter positioning, module recognition for the press controls (such as the number of operating hours clocked, regardless of the module's position within the press) and water cooling.

If a UV module is removed from a docking port the media trunk connection can be plugged in to a designated parking socket so that there are no loose cables lying around.

A UV module can be changed safely within 60 seconds, claimed the company.

Transformers or electronic ballasts are used to select the UV emitters.

They are said to keep the power setting in stand-by mode very low (transformers: below 20 per cent; ballasts: below 10 per cent) for energy saving.

If ballasts are used, the dryer cabinets at the press can be smaller than they would need to be for transformers.

Currently, KBA said it is working on additional ways and means of optimising the power of the emitters, extending their service life and reducing power consumption.

For example, in future the company believes it should be possible to make the UV lamps switch off between sheets.

Depending on the sheet size that could cut energy consumption by as much as 30 per cent.

Iron-doped and gallium-doped UV lamps are available for maximum efficiency in curing ink and opaque white.

Installing a Washtronic system also provides time savings if inter-deck dryer modules are fitted, since they do not have to be switched off during the cleaning cycle.

started developing an in-house range of in 2003.

KBA commented further that apart from ensuring that all systems function as desired, development work on the new range of dryer modules - which began in 2003 - focused on two primary objectives.

Firstly, the company concentrated on maximising flexibility for the benefit of the user by ensuring that UV emitter modules could be plugged in at any position, for example.

The other important issue was to facilitate handling by providing console displays and controls for all key parameters.

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