Equipment & Systems
Advancements in Newspaper Production
By Pulp & Paper Canada
The world-wide newsprint market remains a very large 40 million tonnes a year grade. North America is approaching the last conversions of letterpress-printed newspapers to mainly offset and in some cases flexographic printing presses. Within the n...
By Pulp & Paper Canada
The world-wide newsprint market remains a very large 40 million tonnes a year grade. North America is approaching the last conversions of letterpress-printed newspapers to mainly offset and in some cases flexographic printing presses. Within the next five years, the few remaining locations will complete the conversion from the direct plate to paper letterpress process. This conversion of the industry from letterpress began in the late 1960s with many locations installing offset presses in the 1970s. One of the many advantages was the greatly improved print quality of offset vs letterpress, especially for colour graphics. Due to the contact between the press blankets and 100% of the paper surface, these offset presses made sheet linting a major papermaking concern. Today, a 250,000 copy production between press blanket washes is becoming an industry standard.
In the late 80s and into the early 90s, flexographic printing was introduced to newspaper printing with a period when newspapers moved to flexo printing. This trend has now mostly stopped, with offset again being the method chosen for new newspaper presses. Technology on offset presses allows much faster operation with actual operating speeds of 70,000 copies per hour.
New presses have greatly increased automation for production efficiency and product quality. These systems include automatic colour setting, automatic camera-based registration and compensation setting systems. These high speeds increase the strength demands on the paper as well as lessening the tolerance for defects such as holes and shives in the sheet. High operating speeds has made 50 inches the new standard roll diameter on these presses requiring increased precision in roll winding control.
As well, these rolls must more than ever be received in good condition at customers including not being out of round to allow automatic roll changing at these high speeds. Many new installations feature automated roll handling systems such as high rack storage areas using computerized retrieval cranes and robotic guided vehicles. The demands on suppliers for perfect roll wrapping and scanable roll bar codes becomes a priority.
The major trend over the last 20 years has been the greatly increased use of colour in newspapers for both editorial and advertising. The introduction of the USA Today daily newspaper in 1982 by Gannett influenced this trend. The primary reason for new press projects and adding additional units to presses is the need to print additional colour pages inside sections beyond the traditional sections cover including two-sided, four-colour pages. Most new press installations now consist of press lines where many, if not all units, allow two-sided, four-colour production on stacked tower units. This increased use of colour has changed the demands on newsprint as well. The need for consistent colour between rolls and between mills to produce consistent printed colour has become a major publisher concern. The use of a large percentage of newsprint on four-colour leads, where the sheet is printed in up to eight separate units, increases the wetting of the sheet. This results in increased concerns about dimensional stability of the sheet that causes fan out during printing and sheet curl when the sheet redries.
The increased immediacy of news via electronic means as well as earlier morning delivery times being required by readers has narrowed the production window each night. The trend in production has moved to printing newspapers in more than one press run and assembling the sections together. Many newspaper presses that could print a complete newspaper in one operation (in what is called a collect run where two different plates are installed around the press cylinder and the two halves are assembled in the press folder) are now operated in straight mode where two identical half newspapers are produced in the same time frame. This allows some less time critical sections to be printed early in the evening and then the most time-critical news and sports sections much later due to double the production in the same interval.
In the last two years, presses that have the capacity to print a major daily only in straight runs were introduced and became a major part of the new press market. The tighter production period makes newsprint customers more sensitive of time-consuming paper breaks. The greatly increased amount of advertising now in insert form has caused newspapers to acquire more elaborate inserting equipment to assemble the final product. This expanding insert volume has shifted some newsprint usage from newspapers to commercial insert printers as well as expanding the use of higher value added grades. In addition, these modern inserting facilities allow newspapers to zone their products to very particular areas to satisfy advertiser demands. A few new presses even allow “on the run changing” of a few pages without press stoppages to replate pages.
As most newspaper readers realise, page size has been shrinking in the last 15 year. This trend is based on both reader preference for a smaller, easier-to-read product, as well as the desire to reduce paper usage for economic reasons. The current, most common, North American standard is 12.5 inches originally used in Canada at the Toronto Star. To further decrease paper usage, this size is being reduced slightly by many publishers. These new roll widths create challenges for mills to efficiently trim the paper machines designed for previous width standards.
Philip Plouffe is an engineer at Papier Masson, QC, and is a member of the Printing and Graphic Arts Committee of the Pulp and Paper Technical Association of Canada (PAPTAC).