Causes of surface oxidation of printing plates

There are many reasons for the oxidation of the printing plate surface, which is mainly classified into two factors, man-made and environment. Here are some common situations.

1. Human Factors

(1) The surface of the finished printing plate is not coated or not coated with protective glue in time. It will not affect the plate quality within a short time (1 to 5 minutes). From the time the printing plate is made to the test printing of the machine, forty-five minutes or less, the surface of the printing plate is not easily oxidized in a short time in cold weather, and it is easy for some plate-making personnel or offset printing operators to be paralyzed. For some novices, Due to unfamiliar work, the printing plate is too slow to go over the protection period of the printing plate's own anti-oxidation, causing the printing plate to be dirty on the surface. The common phenomenon is that the handwriting is deformed from burrs and pastes. However, in the higher temperature weather, the surface of the printing plate is easily oxidized, and oxidation spots often appear on the surface two or three minutes after the printing plate is made. Even if the operator's plate mounting technology is perfect, it cannot be taken from the platemaking shop for printing plate printing.

(2) The surface of the printing plate is not or is not timely coated with a protective adhesive during the shutdown. When shutting down, operators often forget to apply protective glue on the surface of the printing plate in time, or delay the application of protective glue.

2. envirnmental factor

(1) Excessive print shop temperature has a direct effect on the printing plate

In summer, due to high temperatures, copper and iron will sweat, and printing plates are no exception. For those offset presses that have a slow speed, their ability to protect the printing plate is relatively poor. Due to the long working hours and the quality of the PS plate itself, thicker writings, burrs, and other slow oxidation phenomena occur on the plate, but the incidence of this condition is extremely low.

(2) Large temperature difference in the printing shop and imbalance of dry humidity

Sometimes the protective rubber on the surface of the backup plate removed from some offset presses loses its protective effect due to the large temperature difference and unbalanced moisture and humidity. In the static protection, the printing plate protective glue will lose its effect once the anti-tide, so that the printing plate is oxidized, the oxidation spots appear on the surface of the printing plate or the writing thickens after the machine, and the printing plate is scrapped. Therefore, whether it is a prepared plate for reuse, or a standby plate that has just been prepared, it should be placed in a well-ventilated, moderate-temperature and dry-humid environment for static protection when not in use, or even protected. The glue is also useless.