The manufacturer of electrostatic printing assist systems (ESA) has been honoured with the International Gravure Award 2023 from the European Rotogravure Association (ERA) in the category “Process Innovation”.
This year, the ERA once again invited the gravure industry to take part in its International Gravure Award. In the category “Process Innovation”, German company Enulec GmbH impressed the jury with its ESA technology, an automated process control system for electrostatic printing aids. The new process allows software and hardware to interact autonomously and combines ESA technology and measuring and discharging systems to create an innovative new product from Enulec.
Patented control technology for printing and converting
The electrostatic printing assistance, discharging and measuring systems are standard equipment on state-of-the-art printing and converting machines. Originally developed solely to improve gravure printing, the patented Enulec ESA and discharging systems ROTO-Film, ROTO-Film-PRO, ROTO-Carton-PRO and StaticLoop 360° also offer maximum safety for the entire production process by minimising static charges.
Enulec concepts offer a tried-and-tested, integral system for flexo and gravure printing, the converting industry and for surface finishing, consisting of the ESA, unloading, measurement and charge control modules, which can be expanded depending on individual requirements. The company keeps an eye on the entire production workflow in all its complexity and diversity and relies on modular technology systems that are compatible down to the first devices developed. This means that customised solutions can be developed for every requirement and every machinery. This offers printers, converters and film manufacturers a significant advantage when planning their strategies, development processes and investments reliably and for the long term.
Reducing static charges on the substrate webs to the lowest possible level is extremely important for printing and further processing in order to achieve optimum print quality and at the same time avoid unwanted sparking and, as a result, accidents at work, print unit fires or material damage. To achieve this, it is necessary to know the interaction between machine, substrate and ink and to take suitable measures to reduce static charges. The package printing and converting sector in particular, with its wide range of printable materials and their individual properties, still poses a particular challenge for the safe operation of an ESA. Equal single-pole ESA charges in the nip within a gravure printing press may further increase the static charge in printing units, rewinders, slitters and laminators. The patented Enulec technologies offer the advantage of a balanced charge with plus/minus polarities.
Forward-looking process design
The development of Enulec’s innovative ESA system was preceded by fundamental considerations:
In many print shops, experience in the printing process often only covers a limited number of the substrates and substrates available on the market. If a new substrate is to be used, this requires a new learning and working process in order to achieve optimum and reliable print results
In addition, the printing industry is facing an increasing shortage of skilled labour, resulting in a loss of experience, while at the same time the variety of printable materials is increasing. This leads to many and time-consuming test runs to achieve optimum print results, resulting in unnecessary costs
Printing machines and converting systems are also continuing to develop, and their production speeds have increased considerably in recent years. There are now machines that process paper webs at a speed of 16 metres per second. However, the higher the speed, the higher the electrostatic charge in the production process.
Numerous articles, forums and association meetings have been calling for years for the opportunities presented by digitalisation to be addressed. Enulec has been following this path and has focussed its research and development work on this. The intensive and global collaboration with colleges, universities and leading machine manufacturers serves as a basis for the company’s continued success.
With the innovative ESA systems Roto-Film-Pro/StaticLoop 360°, Enulec closes the gap between human expertise and the large number of possible substrates with their individual properties.
Intelligent static load monitoring process
The centrepiece of ESA Roto-Film-Pro/StaticLoop 360° is an intelligent static charge monitoring process, which ensures maximum safety and quality, especially in potentially explosive atmospheres. To reduce electrostatic charges, four patented Enulec ESA technologies have been integrated into a measurement and control-based loop system. For this purpose, the system learns the static values during the printing process and then automatically adjusts the power and polarity of the ESA to the lowest achievable static level.
To ensure safe operation of printing and converting machines, Roto-Film-Pro/StaticLoop 360° reduces the static values of the substrate web to the lowest possible level. By preventing uncontrolled discharge of high trapped charges, this new ESA system makes printing on various substrates much safer. Compared to other ESA systems, this innovative solution completely neutralises the electrostatic charges on the film web and significantly reduces the trapped charges (double layer charges) in the film substrate. Another innovation from Enulec is the optional tachometric compensation for automatic control of the ESA intensity depending on the web speed.
To support colour transfer, the ESA must operate within a controlled voltage of 300-1500 volts in the printing gap. When the local static levels there reach a threshold of around 2 kv, the static level is high. However, the system has an automatic earthing switch that safely dissipates the excess energy. Measurements of the static surface energy of the pressure paths do not usually match the values of the internal nip energy. With the Static Inline Control, Enulec offers an ideal addition to the ESA system in the printing and converting sector. The system measures the static charges on the substrate web and triggers an alarm if a set warning level is exceeded. The status and progression of the static charges on the substrate are fully documented.