The differences and characteristics of offset printing, gravure printing, flexographic printing, and silk screen printing

With the development of the economy, packaging printing is increasingly valued, and the choice of printing technology has a direct impact on printing quality, efficiency, cost, etc. This article will share in detail the differences and characteristics of offset printing, gravure printing, flexographic printing, screen printing, and the four major printing methods.

1、 Offset printing

The graphic and non graphic parts of the printing plate are kept flat on the surface, with a layer of oily film covering the graphic and non graphic parts, while the non graphic parts absorb appropriate moisture.

When applying ink, the graphic and textual parts repel moisture and absorb ink, while the non graphic and textual parts absorb moisture and form an anti ink effect.

The printing plates used in lithography include PS plates, gravure plates, protein plates, multi-layer metal plates, etc. The characteristic of the surface structure of these printing plates is that the graphic and textual parts on the plate are almost on the same plane as the non graphic blank.

When printing, it is necessary to first wet the non graphic and textual parts of the printing plate with a dampening solution to form a uniform water film of a certain thickness, and then wet the graphic and textual parts of the printing plate with ink to form a uniform ink film of a certain thickness. Using the principle of oil and water immiscibility, the non graphic and textual parts rely on the water film and ink film to resist each other‘s infiltration. The surface of planographic printing must form two types of surface areas: hydrophilic and oleophobic, and oleophilic and hydrophobic.

The vast majority of books, magazines, picture books, and packaging color boxes are offset printing products. Offset printing is a type of planographic printing. Simply put, offset printing is a printing method that uses rubber (blanket) to transfer the graphics and text on the printing plate to the substrate. It is a planographic printing method with three cylinders (plate, blanket, and imprint). In southern China, this printing method is called offset printing.

Offset printing: Various books, paper posters, brochures, handbags, calendars, and some PVC, PET can also be printed on them.

2、Gravure printing

Gravure printing is a direct printing method that directly imprints the ink contained in the concave pits onto the substrate. The density and depth of the printed image are determined by the size and depth of the pits. If the pits are deep, more ink is contained, and the ink layer left on the substrate after imprinting is thicker; On the contrary, if the pits are shallow, the amount of ink contained will be less, and the ink layer left on the substrate after embossing will be thinner. The intaglio printing plate is composed of pits corresponding to the original text and text, and the surface of the plate.

When printing, ink is filled into the pits, and the ink on the surface of the printing plate is scraped off with a scraper. The printing plate comes into contact with the substrate under a certain pressure, and the ink in the pits is transferred to the substrate to complete the printing.

Plastic bag products are generally gravure printed. Gravure printing has a full and three-dimensional ink color, convex graphics and text, rich layers, clear lines, high quality and long printing plate life, suitable for large-scale printing. Gravure printing can print extremely thin materials, such as plastic films.

The main disadvantages of gravure printing are: complex pre press plate making technology, long cycle, and high plate making cost; Due to the use of volatile solvents, the workshop has a high content of harmful gases, which can cause significant harm to the health of workers; The treatment required for gravure printing practitioners is relatively high.

The intaglio printing process is complex and ink pollutes the environment. These two issues have affected the development of gravure printing. Especially with the reduction of a large number of printed materials and the increasing demand for low-priced printed materials in short editions, gravure printing continues to lose its market share.

3、 Flexographic printing

The most common logistics packaging corrugated paper boxes are flexographic products. Flexographic printing is an evolution of relief printing, which is a direct printing method called flexographic printing due to the use of elastic and raised image plates. The flexographic printing plate is fixed to the printing plate cylinder, and the printing plate is supplied with ink by a carved metal mesh roller.

Flexographic direct printing has the following characteristics:

3.1.The ink layer is thick and the ink color is consistent. 

Although the ink layer of flexographic printing is thinner than gravure printing, it is definitely thicker than offset printing, which is very advantageous for large area color blocks commonly seen in printed packaging products; Due to the use of mesh rollers for ink transfer, generally speaking, if the paper condition and ink condition remain unchanged, the ink color of products from the same batch or different batches can be consistent. This is the most basic requirement for packaging printing, which is also difficult to achieve with offset printing.

3.2 Widely use non-toxic water-based ink for printing. 

Flexographic ink is currently the only non-toxic ink recognized by the American Food and Drug Association among all printing inks. Therefore, flexographic printing, also known as green printing, is widely used in instrument and pharmaceutical packaging, which is beyond the reach of other printing methods.

3.3 Widely applicable printing media.

Flexographic printing machines can not only print various types of paper, but also print aluminum foil, plastic film, adhesive notes, woven bags, non-woven fabrics, and textiles. There are more types of suitable printing media than gravure printing methods. Except for paper, all other media in offset printing cannot or are difficult to print.

3.4 The product has a wide range of applications.

Almost all paper and plastic packaging products can be printed using flexographic printing. In addition to packaging products, newspapers, books, magazines, and other products can also be printed.

3.5 The equipment has strong comprehensive processing capabilities.

Flexographic printing machines can perform post printing processing on the same equipment, such as reverse printing, glazing, laminating, die-cutting, cross cutting, slitting, punching, dragon punching, fan folding, automatic waste removal, etc. They can even add marking, hot stamping or screen printing units to the printing unit.

Therefore, it is not unreasonable for some people to refer to flexographic printing machines as printing processing production lines.

4、Silk screen printing

Screen printing is the closest printing method to our daily lives. The common local UV is screen printing, which can form ink accumulation according to the thickness of the screen, and has a very good three-dimensional effect; Screen printing is also widely used for printing adhesive labels.

When we were children, our exam papers were transcribed and oil printed. The teacher placed wax paper on a steel plate with a mesh pattern, used a pointed engraving pen to engrave the words, and then printed them with an oil printing machine.

This printing method is based on the same principle as our silk screen printing: the screen has hollow parts, and ink is transferred to the substrate (paper, ceramics, etc.) through the holes, forming images or text.

Silk screen printing: on various metals, glass, paper, plastic, wood, ceramics, etc., it is claimed that there is nothing that cannot be printed except for air and water.

Shenzhen Gold Sun Color Printing Factory is a China based book manufacturer, very good at printing hardcover book, photo book, story book, photo album, Printing paper, coloring book, packaging & printing services,  Labels, printing stickers, anti-water labels, vinyl label, custom label book , softcover book, custom book printing hardcover, mini book, photobook printing, hardcover book, , board books, color sticker books, sticker books, packaging boxes for small business, custom book, children board books, kids book, journals, notebooks, Agenda, Customs Calendar, magazines, color books, cookbooks, etc. With ISO-2001 and CE certificate, Gold Sun offers very good price and outstanding service.

Welcome contact us through admin@goldsunprinting.com or add whatsapp  +86 13802583954. Thank you.