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Product category: General Print Supplies, Services for Printers
News Release from: Powervar | Subject: Power conditioners, un-interruptible power supply
Edited by the Printingtalk Editorial Team on 07 February 2008

Electrical Systems Problems Threaten
Print Profits

Behind the success of the digital print sector are some power and energy challenges that threaten profits and competitiveness.

That is according to power conditioners and un-interruptible power supply systems manufacturer Powervar, whose UK country manager, Rob Morris, said he believes that it is not enough to understand the print technology and processes because it is vital to recognise the particular problems posed by the electrical systems on which digital printing relies He commented: "Modern digital presses have non-linear loads with high peak current demands

They depend on computers and adjustable speed drives which, in turn, create harmonic currents that can add severe stress to electrical systems powering the plant.

In addition, the computers and drives themselves are often damaged, or disrupted by power disturbances, such as electrical noise, voltage transients and neutral-to-ground voltage disturbances." Morris explained: "The simple act of protecting printing equipment against problems in the electrical supply has been shown to provide substantial dot gain improvements and improve print registration consistency by as much as 35 per cent over non-protected systems." Powervar said that the fact that most printing equipment comes from various countries can complicate the power issue because of the need for voltage matching transformers.

They can increase costs and, if not properly selected, adversely affect printing process performance.

The company added that whilst studies show that network reliability averages around 99 per cent, that apparently high level means that there are over 88 hours in a year when the power quality is not up to standard.

Morris continued: "Power quality problems cost business GBP7.5 billion per year in the EU and just under GBP100 billion in the USA.

A significant part of this cost is for the repair and replacement of equipment damaged by power disturbances.

All too often the failed circuit boards and damaged power supply units are not immediately identified as power quality issues." He stressed that what is true for other industries equally applies to the printing industry.

And Morris emphasised: "Digital printing technology is playing a key role in helping commercial printing businesses to remain viable and hold their market share in an increasingly competitive marketplace.

This competition does not just come from within the industry but from the internet and the world of multi-media communications.

Indeed, far too many people see traditional print as costly, inflexible and slow." However, he believes that digital printing technology is helping to restore the balance.

It allows companies to print faster and shorten turn-around times and it also means that relatively short runs can be viable, enabling print media to be changed more frequently and kept topical, things at which electronic media excels.

Digital technologies also reduce the cost differential between mono and colour printing, making the latter more economical and enhancing the readership appeal.

And Morris added: "Nevertheless, the printing industry remains highly competitive.

Commercial printers are keenly aware that their businesses are governed by a simple formula - profit is revenue minus cost.

The only ways to make greater profits are to increase revenue or reduce cost and a successful business does both." He said that high on the list of costs that need watching are those associated with the quality and reliability of the electricity that powers digital printing presses.

Energy efficiency, maintenance and repair, productivity and product quality are all directly influenced by the electricity that powers presses.

And he continued: "Power quality has a direct impact on press characteristics, such as dot gain, register, ink density, hue error, grey value and tone value and all of those directly affect customer satisfaction.

Modern digital presses have non-linear loads and have high peak current demands.

This matters because digital presses rely on computer technology driving adjustable speed drives to provide the required levels of efficiency and performance.

"Meanwhile, computer power supplies and adjustable speed drives are sources of harmonic current.

That can put a business's electrical systems under considerable stress meaning that those components can create power factor problems.

Both harmonics and power factor are of great concern to the power supplier who has the right to charge extra if the plant's power factor and harmonic distortion do not fall within certain tolerances." Because of that, continued Morris, power factor problems may not only adversely affect the printing process because they may also result in higher charges for electricity for the supplier.

And he said: "IEEE 519 now describes allowable limits of harmonic current within facilities.

In the United Kingdom, G5/4 guidelines, which have been in effect since 2001, can prohibit the connection of a high harmonic load to the electrical main.

Increasingly, the power companies see these standards as a way of protecting themselves from the problems caused by facilities with high harmonic content.

They can also penalise their customers with poor power factor which, in turn, pushes up the cost of each kilowatt hour of electricity consumed, raising costs and reducing profits." According to Powervar, another factor that compounds those issues is that most major press manufacturers are in Germany and Japan.

Their products may require transformers to meet local voltage requirements in different countries and without proper attention to the design and impedance of the equipment, harmonic, power factor and efficiency problems can be made worse and, as a result, increase costs even further.

Morris commented: "The apparently simple act of preparing the electrical system to deliver the supply the press needs, in a manner acceptable to the power company, whilst meeting all the regulatory standards can become a major cost factor even before the press prints its first page." According to the Organisation for Economic Cooperation and Development (OECD) electrical systems in the developed world achieve quality and reliability levels in the order of about 99 per cent.

Morris observed: "At first glance this is impressive but, looked at differently, 99 per cent reliability means that there are more than 88 hours per year when electrical power is not up to the quality standards needed by high technology systems.

It is likely that these periods will coincide with periods of high demand when a plant is in full swing to meet urgent deadlines.

"Also, most power quality problems, such as voltage spikes are only a few millionths of a second in duration, literally hundreds of millions of these disturbances occur during this 88 hour time frame - any one of them with potential to do untold damage." He added that European Union estimates put the cost of power quality problems as high as EUR10 billion annually.

In the USA they are reckoned to cost USD188 billion per year.

A major part of that cost is attributable to the repair and replacement of hardware damaged by power disturbances.

That includes damaged power supplies, failed circuit boards and no-fault-found reports, which are failures that increase the cost and hit profits and they are good indicators of existing power quality problems in a plant.

Powervar believes that in conventional printing make-ready can be the single largest production cost.

On short runs, make-ready can be a big part of the total cost, whilst on longer runs, the cost of each page drops dramatically once printing has started.

And Morris said: "It is easy to see why anything that forces a repeat of make-ready pushes costs up and reduces margins.

However, this can happen if power quality problems cause system failure and as a result productivity drops and manpower and material are wasted." He said: "More than ever, commercial printers must continuously monitor and measure the performance of their single largest investment - their digital printing presses.

Profits mean always satisfying customer quality demands and avoiding reprints, which quickly wipe out any profit.

In the past, printing presses were only subjected to rigorous acceptance testing on installation but today these tests are an integral part of any printer's quality control initiatives." Testing protocols from organisation like GATF and IFRA provide printers with process audit guidelines for press characteristics, such as dot-gain, register, ink density, hue error, gray balance and tone value.

According to GATF, measuring minimum and maximum reproducible dot percentage (dot gain) is perhaps the single most important way of verifying the quality control process, commented Powervar.

And Morris explained: "It might come as a surprise to discover that many stringent tests carried out using these protocols on presses, found that substantial improvements in dot gain were achieved when the digital press electronics were protected from harmonic currents, power line noise and voltage transients.

In such plants, print registration was shown to improve by as much as 35 per cent.

Clearly, the quality of the electrical power feeding the printing press is a critical factor in producing a quality printed product." He concluded: "Whilst digital printing technologies offer cost and capacity benefits, these can be eroded by power quality problems.

Where so many companies survive on slim margins the need to do anything that can eliminate downtime, poor productivity and product quality problems, is paramount.

Assuring the quality of power to the plant should become a priority.

Once this is under control, the attention can be placed on core business issues, such as reducing costs and raising sales.".

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