A buildup of ink pigment particles, dried ink vehicle, dampening solution gum, particles of paper fiber and coating, and other material on ink rollers, a problem occurring on offset presses. The accumulation of glaze (typically on resilient rollers, such as form rollers) is caused by a combination of press chemistry and improper cleaning and maintenance. Ink rollers effect the transfer of ink by virtue of the presence of tiny protrusions on the surface of the rubber coating, and the flexibility of these protrusions allow consistent and effective ink coverage. The materials which cause glaze fill up the space between these protrusions, and reduce their flexibility, resulting in the decreased efficacy of ink transfer. Glazed rollers can cause streaking, inconsistent ink coverage, and other such problems. The process of deglazing rollers can be effected using basic washup techniques and properly formulated cleaning solvents. (Improper solvents are also a cause of glaze.)
|