What is offset printing?
Hopcungcaocap – Surely, all of us have heard of the offset printing technique. This is a fairly common technique in printing on different surfaces. So what is offset printing, its characteristics, and the printing process? Let’s find out with Hoang Vuong paper packaging.
What is offset printing?
Offset printing is a printing technique that uses images adhered with ink onto offset rubber sheets, then the sheets are used to print onto paper. This technique limits the water from sticking to the paper.
This technique has the advantage of producing high-quality, sharp images that are less prone to ink smudging.
It can print on many types of surfaces, flat or non-flat, such as wood, fabric, metal, rough paper, and leather. The prints are easy to manufacture and have a longer lifespan than other printing techniques.
Structure of offset printing machine
The offset printing machine consists of a paper supply unit, a printing unit, an intermediate transfer device, a paper delivery unit, and a support unit.
The printing unit, in particular, has three main cylinders and a dampening system, and an ink system, specifically:
- Plate cylinder: a metal cylinder that holds the inked image and non-printing areas
- Blanket cylinder: an offset rubber cylinder coated with a fabric layer to transfer the image from the plate cylinder to the printed surface.
- Impression cylinder: a rotating cylinder that comes into contact with the blanket cylinder to transfer the inked image to the paper or other printed material.
- Dampening system: includes dampening solution rollers and additives such as acid, gum arabic, isopropyl alcohol, or other dampening agents.
- Ink system: includes ink rollers for the printing plate.
- Paper feed unit: responsible for feeding paper and other printed materials into the printing unit.
- Intermediate transfer devices: transport the paper through the printing process.
- Paper delivery unit: receives the printed paper and ensures even stacking.
Offset printing process
Step 1: Plate design
Create the object to be printed on the computer, including images and processed information, arranged to be harmonious and impressive to meet customers’ needs.
Step 2: Output Film
After designing the print plate, proceed to output the film. For a flyer with an image, the file is output to four sheets corresponding to the four CMYK colors (Cyan – Magenta – Yellow – Black) – these are the most common colors in offset printing.
Step 3: Expose the zinc plate
When the 4 film sheets have been output, the printer will expose each output film to each zinc plate to get 4 zinc plates representing the 4 CMYK colors.
Step 4: Conduct offset printing
Proceed to print each color; it doesn’t matter which color is printed first or last. First, the printer chooses one of the 4 color plates and installs it on the printing press roller, then the roller presses the printing element onto the paper, and after printing the required amount, the printer removes the plate and cleans the old ink, then installs a new plate. Sequentially until all 4 colors are finished, these 4 colors will be overlaid to produce the final print. During the printing process, each color is run 50 times until the print has a stable hue, and the total number of test prints is up to 200. Therefore, when printing with this technique, people often have to calculate around 200 sheets of paper to compensate for paper waste.
Step 5: Post-printing processing
After printing, there are post-printing processing steps, such as laminating (matte or glossy lamination) and cutting to produce the final product. Lamination is applying a thin film layer to smooth the paper and enhance the image quality (this step is optional, depending on the customer’s needs).
Above are detailed shares about the offset printing technique. It can be seen that this technique has many advantages and is widely used.
If you want to create beautiful, sharp, high-quality print products, don’t hesitate to contact us for the best service!
HOANG VUONG PAPER PACKAGING CO., LTD.
With over 6 years of experience in the paper packaging industry and having built a reputable brand on the market, Hoang Vuong Paper Packaging Co., Ltd. is proud to be a private packaging enterprise in Vietnam that accompanies many big brands both domestically and internationally.
- Address: 10/6C 10th Street, Binh Hung Hoa A Ward, Binh Tan District, Ho Chi Minh City
- Phone number: 0908.863.965 (Mr. Le Hong Son)
- Phone: 028.62696129 – 028.22481926
- Fax: 08.62696032
- E-mail: email@example.com
- Website: www.hopcungcaocap.vn
- Fanpage: Hoang Vuong Paper Packaging Co., Ltd