Chapter 2 Handling Paper
Moisture content is defined as the percent ratio of moisture to the dry mass of the paper. Moisture can affect the paper’s ap- pearance, feedability, curl, electrostatic properties, and toner fusing characteristics.
The moisture content of the paper varies with the relative humidity in the room. When the relative humidity is high and the paper absorbs moisture, the paper edges expand, becoming wavy in appearance. When the relative humidity is low and the paper loses moisture, the edges shrink and tighten, and print contrast may suffer.
Wavy or tight edges can cause misfeeding and alignment anomalies. The moisture content of the paper should be 4 to 6%. To ensure the proper moisture content, it is important to store the paper in a controlled environment. Some tips on moisture control are:
•Store paper in a cool, dry location.
•Keep the paper in its wrapping as long as possible. Rewrap paper that is not in use.
•Store paper in its original carton. Place a pallet, etc., under the carton to separate it from the floor.
•After removing paper from storage, let it stand in the same room as the printer for 48 hours before use.
•Avoid leaving paper where it is exposed to heat, sunlight, or damp.
Paper GrainWhen paper is manufactured, it is cut into sheets with the grain running parallel to the length (long grain) or parallel to the width (short grain). Short grain paper can cause feeding problems in the printer. All paper used in the printer should be long grain.
Other Paper PropertiesPorosity: Refers to the density of the paper structure; that is, how openly or compactly the fibers are bonded.
Stiffness: Limp paper can buckle inside the printer, while paper that is too stiff may bind. Either way the result is a paper jam.
Curl: Most paper has a natural tendency to curl in one direc- tion. The paper should be loaded so that the natural curl is downward, to counteract the upward curl imparted by the printer. Printed sheets will then come out flat. Most paper also has a top and bottom surface. Loading instructions are usually given on the paper package.
NOTE
If the paper is considerably curled in one direction, e.g. when the paper was used to print on one side, try to roll the paper in the opposite direction to counteract the curl. Printed sheets will then come out flat.
Electrostatic properties: During the printing process, the paper is electrostatically charged to attract the toner. The paper must be able to release this charge so that printed sheets do not cling together in the output tray.
Whiteness: The contrast of the printed page depends on the whiteness of the paper. Whiter paper provides a sharper, brighter appearance.
Quality control: Uneven sheet size, corners that are not square, ragged edges, welded (uncut) sheets, and crushed edges and corners can cause the printer to malfunction in various ways. A quality paper supplier should take considerable care to ensure that these problems do not occur.
Packaging: Paper should be packed in a sturdy carton to protect it from damage during transport. Quality paper obtained from a reputable supplier is usually properly packaged.