Graphic Design & Printing Technology

Graphic Design & Printing Technology

Unit - 4

Web Offset Press...........................................................................

Introduction

Web offset presses feed from roll or web of paper instead of individual sheet.
The term web-fed is commonly used to distinguish these presses from sheet
fed presses. They are extremely fast. For this reason they are typically used
for long run works. Large daily newpapers are printed on web press. An
advantage of web press is that finishing operations can be performed inline. A
variety of finishing operations like folding can be incorporated into the press
run. Web presses produce medium run newpapers, magazines, business forms,
mail order catalogues, gift wrappings, books, inserts, and all type of commercial
printing.

Learning outcomes
The learner:

• categorises web offset presses based on its design.


• understands the operation of a web offset machine.


• understands the Inline finishing methods in a web offset machine.


• identifies different types of printing papers used in a web offset press.


• understands the working of a press console.

Web offset press designs

There are mainly four types of web offset presses.

1. Perfecting blanket to blanket


2. Inline presses


3. Stack / Tower Presses


4. Common Impression Cylinder (CIC)presses (Satellite units)

1.Perfecting blanket to blanket :- Presses printing on both sides of the paper
at the same time are known as perfecting
presses or perfectors.

A perfecting blanket to blanket web offset
press does not have impression cylinder.
Instead, the blanket cylinder of one unit
serves as the impression cylinder for the
other units, and vice versa. Each printing
unit has two plate cylinders and two blanket
cylinders. The paper is printed on both sides
at the same time as it passes between the two
blanket cylinders.