The Offset Printing Process : How Its Works

There many printing technologies in practice in with accordance to need for time and businesses. Regardless of the digital era, print media is still tremendously prevalent. Publicity in the shape of brochures, artworks and flyers are specially printed and delivered in huge amounts daily. The printing of enormous quantities of paper would be unimaginable without offset printing. Offset printing technology is considered as cost-efficient and high-quality printing technology. The process creates prints with ironic; plane artifacts deprived of the streaking originate in reduced quality copies. Authentic inks are utilized instead of toners. The appearance and impression of every offset product approach through as more proficient.

Definition of Offset Printing Process:

Offset printing could be defined as a printing method that includes the shifting of an image from a metallic plate to a rubber blanket or rollers prior to being printed on the receiving means, which is most frequently, paper. In this process, the paper does not come in straight interaction with the metal plates. The offset printing process is the oldest technique among current printing technologies. It works under the concept of perfection over time. It is used to print newspapers, brochures, magazines, labels, and books, etc. Offset printing technology is considered as the pillar of the printing industry. Almost every viable printer does it. But the excellence of the end product is frequently because of the supervision, proficiency, and apparatus utilized by the printer.

Steps of Offset Printing Process:

There are three main steps of the offset printing process as Pre-press Production, Press Run and Bindery. 

Step 1: Pre-press Production:

With reference to the offset printing process’s definition, we can conclude that a cylinder protected with a rubber blanket is located among printing plate and paper to be printed. In this way, printing ink is conveyed circuitously on the printing sheet. These printing plates are made of millimeter-thin aluminum and are created separately for each printing ink and a sum of 4 plates with accordance to CMYK colors. The image surfaces are placed on a level on the printing plates before filling them with inks to keep the colors on the intended place, which will provide prints printed in the respective color. In the next step, these printing plates are inserted into the corresponding printing unit in the offset printing machine. The sheet which is required to be printed passes through all 4 units after one another which outcomes in all colors being printed on top of each other. 

Step 2: Press Run:

The real printing comes into existence with the help of 3 printing cylinders known as Plate Cylinder, Rubber Blanket Cylinder, and Impression cylinder. The prepared printing plate is stretched on the plate cylinder to absorb the ink from the inking system in the offset printing machine on print required areas of the printing plate. The remaining areas of the printing plate are moisturized with water with the help of a roller in the damping unit. The right impression image is transferred back to front on a rubber blanket located on the rubber blanket cylinder. And at last the reserved image is again transferred on the paper which passes between the printing cylinder and rubber blanket cylinder. The color registers and ink application are tested through line testers after the print process to check the quality and perfection of the process.

Step 3: Bindery:

In fact, it is not included in the printing process but actually post-processing of printed materials. In this step in the offset printing process, the printed papers or sheets are cut, organized and bound if these are for books or magazines. If it is a single page broacher the printed paper is just cut only with cutters and other machines like switcher and binder are used to arrange and bind them. 

Advantages:

Offset printing is the best choice for the large volume's images to be printed with accurate, clean and all-around professional quality. The overall cost factor is beneficial with using an offset printing process as more sheets get printed in the cost of each unit of print in each cycle. It is feasible for a variety of printing surfaces like leather, cloth, plastic, metal, and wood, etc. It aids to reduce wasted prints due to faded inks and insufficient contrasts. The most important advantage of the offset printing process is easy and quick production of printing plates, which allow you to print extra prints in less period of time. 

Disadvantages:

Because of the chemical corrosion, the printing plates might become sensitive and anodized, aluminum plates have more chances to be sensitive which might cause print on non-image areas and destroy the printing material.   If you have an urgent task the offset printing technology might not provide a quicker solution as before printing the job the printing plates must be developed. The offset printing is not recommended for the smaller label runs due to its high initial setup cost.