The Printing Process - Sheet Offset Press

 

A sheet-fed offset press is made of 4 sections which are the feeder and lay system, the printing units, the delivery system and the control station.

The feeder and lay system - this section checks that papers from the paper stack are loaded one by one into the press.

The printing units - it is where each single color is printing on the paper on one side. It is composed of 5 print units (each unit prints one color (Cyan - Magenta - Yellow - Black (K) ), the 5th unit is the mix of color which is usually done by hand. If both sides have to be printed, there is a cylinder between the first set of units and the second one that realigns and reorganizes the paper in order to print on the other side.

The delivery system - It is a system that put the paper on the delivery board. After this process, a sample of the printing is checked on the control station in order to ensure the quality of the printing.

 

However before anything can be printed on the sheet offset press, the artwork should be processed on a process plate. 

I called this stage , the default stage.

After the default stage, the plate is placed into the press which is wrapped on a cylinder.  

Since the papers or sheets are stuck on the top of each other on the delivery section, "anti set-off" powder is sprayed on each sheets before they are being stacked on the delivery system.

Here is a link for more information:

https://www.youtube.com/watch?v=RW1HJdW5XLs