Spokane Cleans Out Its Webs
After a typical press run of 120,000 impressions, Pressroom Supervisor John Wilhelm of The Spokesman-Review in Spokane, Wash., would see debris literally peel or flake off his printing blankets. Not only did the blanket piling shorten blanket life; but it also affected color reproduction, made cleaning more difficult, and increased consumables use and maintenance time.
Wilhelm thought that if the web could somehow be cleaned before printing, the piling could be stopped before it started. Web-cleaning systems exist, but had seldom been implemented on a newspaper press. So last December, Kaim & Associates of Lodi, Wis., and The Spokesman-Review began testing the Twin Turbo Web Cleaning System.
Spokane has been able to eliminate more than 15 consecutive blanket cleanings. Their blankets now run more than 2 million impressions before cleaning. Also:
- Blankets are no longer smashed, especially in the once-problematic reel-tension-paster static-belt paths.
- Color reproduction has improved, with start-of-run and end-of-run copies showing greater consistency.
- With piling eliminated, all blankets retain fixed diameters, improving registration color-fit between printing couples.
- Ink trains, pipe rollers and angle bars stay cleaner, because loose web debris is no longer migrating from the web's surface.
The Twin Turbo Web Cleaning System does not contact the web's surface. A high-speed turbo buff on each side of the web spins, creating a high-energy impinging force that fractures the web's boundary layer of air, loosening debris. The debris, mostly paper dust and filler, is collected by the system's Ventec skiving capture hoods, discharged from a port and vacuum-carried to a dust-collection center. Spokane ultimately plans to place the system on all web leads.
Testing Key to Runability, Printability
by Greg Francis
Everyone knows you can't print a newspaper on just any old newsprint. Using the wrong paper will harm runability (the ability to get through the presses without breaking) and printability (the ability to yield high-quality color). But which of the many tests performed by suppliers offer the best clues to controlling these variables?
Newspaper quality managers and their paper suppliers agree to a large extent about which tests are important. However, they sometimes differ on which are the most critical.
Newspapers place a higher value on tests relating to runability, says Dale Stisser, technical-service manager for North Pacific Paper Corp. "They place the most importance on tests for rupture, tear or break."
Others disagree. Ruth Bohner, NAA's production-materials director, rates basis weight as most important. Bohner argues that if newsprint is too heavy, a newspaper may not obtain a sufficient number of printed sheets from a roll. On the other hand, lighter paper can lack strength and opacity.
Another measure of runability is the paper's tendency to tear, typically measured in both the direction the paper passes through the press and the perpendicular, or cross, direction. Although newspapers have long requested both tests, some suppliers question the value of the cross-directional measure. Ivan Pikulik, manager of papermaking programs for PAPRICAN, a Canadian organization of pulp and paper manufacturers, says the test is expensive and may not be a good predictor of runability.
Moisture, however, certainly is. And while overly damp paper can cause major problems, the more common problem is dryness, which can cause paper to snap or even catch fire.
Despite the overwhelming importance of runability, four of the most important newsprint tests—color, brightness, opacity and smoothness—relate to printability, says Bohner. Opacity is especially important to many advertisers, who believe it can have a major effect on an ad's appearance. Smoothness is also critical: If the paper is too smooth, the ink will not dry correctly; if it is too rough, it will not print properly.
Experts mostly agree on which test results newspapers should ask their manufacturers to provide, but say there are no hard-and-fast rules. "Different applications require a different thickness and smoothness of print," emphasizes Jim Harrison, director of quality assurance for Bowater Inc.'s Newsprint and Directory division.
Greg Francis is an Arlington, Va., free-lancer. E-mail, grfhome@aol.com; phone, (703) 838-9565.