Analysis of scratches on offset printing (2)

Two other causes of streak

(1) Rubber blankets with poor blanket quality are more prone to ink streaks than high quality, flat blankets. Air cushion blankets are better than ordinary blankets.

(2) Hard pad liner Although the printing effect is good, it is very sensitive to the accuracy of the machine, and it is prone to streaks. The blanket cylinder and plate cylinder have low printing pressure and are prone to ink streaks.

(3) The plate version of the printing plate has great friction and is not prone to ink bars. However, in the field version, the thin line version is easy to slide, especially for the large-area field version. The thin line version is most prone to ink streaks.

(4) Paper with high paper smoothness is prone to ink streaks. Example: Aluminum foil, advanced coated paper.

(5) thick thick ink ink viscosity, ink marks are not easy to appear, and thin, high transparency of ink ink marks are obvious, in addition, ink type has an impact on the production of ink bars. Black ink and blue ink are prone to dark bars, while yellow ink is similar to paper and ink marks are not obvious.

Three about ghosting:

Ghosting means that the same color blocks in the finished product have different dark shadows. The initial cause of ghosting is often due to improper imposition. The images that are not in one hue are combined on one layout. Because different hue requirements are not the same, calibrating the hue of a single image will destroy the hue of another image on the same surface, especially when horizontal and vertical cross-imposition occurs. One problem is particularly prominent. For example, when the dot density of CMYK is between 50% and 70%, printing adjustment is not in place, and ink bars similar to ghosts are prone to appear.