| 摘要 |
<p>A method of preventing a non-image portion of a printing plate and the surface of a wet roller in an offset printer from being soiled with an oily material, such as printing ink, by applying ultrasonic waves from the ultrasonic wave generators provided on a plate cylinder roller and the wet roller to the surfaces of the same rollers in motion. According to this method, the deposition of an oily material, such as printing ink on a non-image portion of a printing plate and the surface of the wet roller can be prevented effectively by a very simply constructed apparatus.</p> |
