Offset Printing

Topic:Offset printing, often called planographic printing, prints from a flat surface with image and non-image areas on the same surface. In addition, unlike the other printing methods that print from wrong-reading plates, the offset plate contains a right-reading image. Discuss how printing can be done from a flat surface and why offset printing prints from a right-reading plate.


Offset Printing uses a cylinder or roller that has been wrapped with a plate of the image that is going to be reproduced. In this example the plate would a right reading image. Ink is applied to the plate with inking rollers. Water is used to create negative areas where because the oil based ink will not stick. This plate cylinder comes in contact with another cylinder, which is known as a rubber blanket. The ink is transferred from the plate to the rubber blanket and then holds the image as wrong reading. A third cylinder, the impression cylinder, then comes in contact with the rubber blanket with the paper placed between these two cylinders. The ink on the rubber blanket is then transferred to the paper being fed between the rubber blanket and the impression cylinder and produces a right reading image on the paper.

Resources:
Foundations of Electronic Production G322 UG . Week Six Online Lecture : Making a Printing Plate 5 2010

Frank J, Romano. Pocket Guide to Digital Prepress. Clifton Park, NY: Delmar, Cengage Learning, 1996.