HP 2300d Service Manual - Page 45

Storing print media Ideally, the printing and media storage environment should be at or near room temperature, and not too dry or too humid. Remember that paper is hygroscopic; it absorbs and loses moisture rapidly. Heat works with humidity to damage paper. Heat causes the moisture in paper to evaporate, while cold causes it to condense on the sheets. Heating systems and air conditioners remove most of the humidity from a room. As a paper package is opened and used, it loses moisture, which causes streaks and smudging in the printed output. Humid weather or water coolers can increase the humidity in a room. As paper is opened and used, it absorbs any excess moisture, which causes light print and dropouts in the printed output. Also, as paper loses and gains moisture, it can distort. This can cause jams. As a result, paper storage and handling are as important as the paper-making process itself. Paper storage environmental conditions directly affect the feed operation. Users should not purchase more paper than can be easily used in a short time (about three months). Paper stored for long periods might experience heat and moisture extremes, which can cause damage. Planning is important to prevent damage to a large supply of paper. Unopened paper in sealed reams can remain stable for several months before use. Opened packages of paper have more potential for environmental damage, especially if they are not wrapped with a moisture-proof barrier. A well-maintained paper-storage environment ensures optimum printer performance. The required environmental conditions are 20 degrees to 24 degrees C (68 degrees to 75 degrees F), with relative humidity of 45 percent to 55 percent. The following guidelines should be helpful when evaluating the papers storage environment: q Paper should be stored at or near room temperature. q The air should not be too dry or too humid. q The best way to store an opened ream of paper is to rewrap it tightly in its moisture-proof wrapping. If the printer environment is subject to extremes, unwrap only the amount of paper that will be used during the day's operation to prevent unwanted moisture changes. Shipping print media When shipping print media through different environments, plastic-wrap all cartons on the shipping pallet. When shipping media across bodies of water, also wrap individual cartons. The packaging must protect the media from physical damage. Paper fillers Additional chemicals and fillers are frequently added to paper during the manufacturing process. These can affect the paper strength, pick resistance, printability, bulk, feel, and color. An emulsion that contains wax, rosin, starch, or other non-water soluble materials is added to the paper pulp to help control the penetration of water and other liquids. Dyes are added and the paper might be bleached. Bleaching is a multistep process that uses chemicals, such as hydrogen peroxide and chlorine dioxide. Finely ground fillers, such as clay, talc, and calcium carbonate, might be added to even out the "peaks and valleys" that occur in the paper mixture, and to serve as brighteners. Over time, these fillers can build up on internal assemblies of the printer such as rollers or the print cartridge. This buildup can eventually cause jams and print defects. To minimize this risk, periodically clean the printer according to procedures (see "Cleaning the printer" on page 75). ENWW 2 Installation 43