American Printer's mission is to be the most reliable and authoritative source of information on integrating tomorrow's technology with today's management.

Digital media is the key to optimal print quality

Oct 1, 2002 12:00 AM


         Subscribe in NewsGator Online   Subscribe in Bloglines

Advertorial by Xerox Supplies Business Group

When Gutenberg first invented moveable type in the 15th century, little did he know that he would become the father of printing technology for more than 500 years. As the art of printing advanced, different types of paper stock and inks were developed to achieve the best quality results. Papers and inks are designed to get the most out of the press, whether it be sheetfed offset, web offset, heatset, non-heatset, gravure or flexographic. Anyone associated with the creation and production of a printed job understands the “ink on paper” environment and works according to clear-cut guidelines.

Just as in the traditional world, digital printing requires papers that are designed to be receptive to toners and can withstand the high-heat of the electrophotographic process. Digital color printing has raised the bar for media development. One paper size doesn't fit all in digital printing, just as it doesn't in the offset world. Toners and media need to match the print technology to ensure that you get the best possible performance out of the equipment.

OPTIMIZING QUALITY

Digitally optimized papers are designed to ensure better toner adhesion, cleaner operation, reduced mottle and a better image quality overall. Properly designed papers for digital printing help printers achieve crisper images with fewer equipment jams and greater compatibility with finishing equipment.

For example, an uneven surface and poor toner transfer due to sub-optimal moisture content plus a lack of consideration for the paper's electrical properties leads to heavy toner mottle. Paper dust particles can cause interference resulting in white specks in the solid areas, called picking or hickies. Other common quality issues include offsetting and transferring to the underside of the next sheet, which is caused by poor toner adhesion. While offsetting is a problem in both offset and digital printing processes, the root causes are quite different.

Halo and graininess are two other image quality issues. Halo effects, caused by dark lines and letters printed on a colored background, are a type of defect associated with the smoothness of the stock. Graininess is a finer type of mottle caused by surface roughness and is influenced by the flow properties of toners and the stock's porosity and permeability.

Using digitally optimized media, along with the correct settings, will prevent halo effects and minimize graininess.

White spot deletions are the result of paper dust accumulating in the developer. Paper dust comes from sheets that have not been properly cut, such as offset grades that have been guillotined or from papers with high filler levels. Again, it is important to remember that problems can and do arise from using paper grades not specifically designed for digital printing.

In addition, imprecise cutting can cause jamming as the paper is fed from the tray. Papers optimized for digital printing have minimal paper dust and are precision cut to eliminate paper-related problems.

As color is transferred onto paper, the positioning of the paper is critical. Minor variations in dimensions can cause image mis-registrations on the paper, which, in turn, causes side-to-side alignment differences. Consistent sheet dimensions are imperative to maintaining correct registration and can be ensured by using precision sheeted grades rather than those that have been guillotine trimmed on the shop floor.

A PERFORMANCE LEADER

Few companies are taking a leadership role in developing digitally optimized media. Xerox Supplies, for example, understands the need to develop papers perfectly paired to machines in order to produce the best-looking printed job possible — whether it's a presentation or a marketing brochure. A Xerox team of paper and chemical engineers, working with other technical and marketing experts, approach product development with an understanding of the interaction among paper, toner and print engines. Balancing paper characteristics with digital machine design ensures users of a consistent high quality, uniform image and overall better digital performance, which leads to high customer satisfaction.

Xerox Supplies offers a wide assortment of digitally optimized paper products designed to ensure users get the most from their equipment investment from both a productivity and quality perspective. Xerox offers a broad portfolio of digitally optimized media. With products available in all of the digital sizes — including 18 × 12 inches for full-bleed applications — the papers have precision cut edges. Printers don't have to waste time and money guillotining offset products that weren't designed for digital equipment.

All Xerox papers are manufactured with lower filler levels and cut using rotary slitters with vacuum heads that extract paper dust generated in the process. This ensures printers of cleaner printing, while preventing machine and document contamination and potential jamming problems.

Stock selection, application design and end use affect the quality of digital print output.

Just like offset printing, digital printing requires matching paper characteristics with the equipment in use. Printing performance is a balance of paper quality and printer design, so it is important to select digital media designed for digital printing equipment.