An on-line viscometer that requires virtually no maintenance and provides a continuous real-time readout is playing a key role in keeping the production lines running for a major toner producer.

Viscosity is not usually a property you would associate with the highly-staining powdered ink toner used in printers and photocopiers. But an XL7 on-line viscometer from Hydramotion is playing a key role in keeping the production lines running for a major toner producer. Toner actually consists of pigment particles encapsulated in a thermoplastics resin.

In a photocopier or printer, the toner is transferred electrostatically to the paper, which then passes between a pair of heated rollers.

The toner particles melt and fuse with the paper fibres to produce the finished image.

The electrical charge and fixing characteristics of the toner are largely determined by the resin, which is typically a styrene-acrylic copolymer.

In the production of polystyrene the degree of polymerisation directly affects its viscosity, which in turn determines the quality of the final product.

Careful monitoring of viscosity is therefore essential throughout the production process.

Recognising the need for a robust and reliable viscometer, the company's research department recommended Hydramotion.

The Hydramotion XL7 is easy to install and simple to operate, requires virtually no maintenance and provides a continuous real-time readout on a dedicated signal processor as well as 4-20mA analogue and RS232 serial data outputs.

As the polymerisation is carried out in a hazardous area at 200 deg C, Hydramotion supplied an intrinsically safe version of its standard high-temperature instrument, enabling production staff to track polymer viscosity during the whole production process.

The viscometer has given managers a much higher level of control over the process than was previously possible.

'It operated fine.

We now have continuous readout of product property,' commented one of the engineers on the site.