Gas analyser checks printers for compliance and safety.

A leading digital print technology company, Tonejet, recently purchased a portable VOC monitor from Ashtead Technology as part of an ongoing programme to ensure the protection of staff, and to assist in conformity with the ATEX Directive as part of the Machinery Directive 2006/42/EEC on CE-Marking.

Technological developments in the print and coatings sectors have delivered a wide variety of advantages including a dramatic reduction in the use of solvents and other volatile organic compounds (VOCs). For example, Tonejet has developed a unique jetting process which electrostatically ejects charged pigment ink particles from a linear array of ejector tips. This no-nozzle printing technology is able to deposit concentrated pigmented inks, achieving a super-thin ink layer of less than 0.5μm.

The ink consists of charged pigment particles in a non-conducting carrier liquid, and since the pigment particles are charged and the carrier oil is insulating, the pigment particles are preferentially jetted which creates a concentrated pigmented jet, which in turn results in a very thin, yet dense, ink layer on the substrate, and utilises 10-20x less ink than traditional inkjet processes. This saves costs, dramatically lowers VOC emissions and enables printing on a wide range of substrates for both flat and curved surfaces such as beverage cans.

Following the printing process, a thin layer of clear varnish is applied to protect the print. Both the print and varnish processes result in the loss of small amounts of vapour, and it is these that Tonejet needed to measure. Ashtead Technology was therefore consulted to determine the best monitoring technology for this application.

You can buy too!
Ashtead Technology maintains a large fleet of environmental monitoring instruments which it makes available for hire. However, many of the more popular instruments are also available for sale. In addition, Ashtead provides a full maintenance and calibration service for VOC monitors. This experience with a variety of brands and technologies puts Ashtead’s engineers in an ideal position to make informed recommendations, and following discussions with Tonejet, it was decided that the MiniRAE 3000 would be the most appropriate instrument.

The MiniRAE 3000 is the latest in a popular range of portable VOC detectors. With a response time of just 3 seconds, the instrument enables users to quickly identify sources of VOCs, stretching from 0.1 -15,000ppm. An improved auto-cleaning PhotoIonisation Detector (PID), with built-in humidity compensation, ensures long-term reliability and built-in correction factors enable the measurement of over 200 compounds. Readings can be stored in an enormous on-board memory; capable of logging data for up to 6 months at 1-minute intervals.

Tonejet manufactures both print engine components and complete printing machines, all of which undergo the necessary conformity checks for both EU and USA regulations. “Following initial training from Ashtead staff, we have been very pleased with the performance of the PID and with Ashtead’s service,” comments Tonejet’s Ian Ingham. “Our VOC levels are a fraction of the permitted levels, but we need accurate data for conformity and for ongoing assurance that the health and wellbeing of our staff are protected.”

Emphasising the importance of the initial training, Ashtead’s Josh Thomas says: “PIDs are highly sensitive to almost all VOCs, so it is important for the instrument to be set up correctly. We also supplied Tonejet with calibration gas, so following the training; they will be able to undertake their own calibrations.”

“Tonejet are using the PID every day as part of their normal work procedures, so in this instance it made sense for them to purchase the instrument rather than rent it. For others, with an infrequent or project based requirement, instrument hire would be the preferred option.”