Offset printing paper is one of the typical representative types of cultural and printing paper. Copy paper should actually be referred to as anti-static copy paper, because after being treated with anti-static treatment, the paper is not easily stuck together in the printer or copy due to static electricity.
The difference between photocopy paper and Offset printing paper lies in the following aspects:
1.Paper surface treatment
Paper surface treatment (smoothness and stiffness): Generally, Offset printing paper is used for printing. The traditional hard pressing method is used to treat the surface of the paper to achieve the required smoothness for printing. Different paper feeding methods can require lower smoothness.
Electrostatic copying paper: Advanced soft calendering technology is used for paper surface treatment, and relatively high surface roughness can achieve good loose thickness and stiffness, reducing the paper jamming rate of copying paper and maintaining good friction with the paper roller to ensure smooth feeding. However, excessive roughness can easily lead to poor feeding and paper jamming, while low roughness can cause slipping with the paper roller and paper jamming.
Offset printing paper does not require stiffness, while photocopy paper requires higher stiffness because the stiffness of the paper directly affects the copying effect. In addition, Offset printing paper requires lower thickness and higher smoothness, while photocopy paper requires higher thickness and smoothness. Taking 70G photocopy paper as an example, it is generally required to achieve a thickness of 96-100UM with a smooth front and back average of 25S or more.
2.Moisture content
The moisture content of offset printing paper for printing is generally higher (6-8%), while the moisture content of electrostatic copying paper is lower (3.8-5%). When copying, low moisture content can effectively reduce the curling caused by instantaneous high temperature and pressure. If offset printing paper is used instead of copy paper, the paper may become uneven after copying due to the high moisture content. For offset printing paper printing, low moisture content can cause the paper to stretch and shrink when encountering water during the printing process, resulting in inaccurate printing.
3.Whiteness
The whiteness of offset printing paper for general printing is low, while the whiteness of electrostatic copying paper is high, with the addition of a luminescent agent.