About flexographic printing
Flexographic printing is a relief printing method, originally known as aniline printing, which originated in the early 1920s in the United States. Due to the toxic use of aniline dye ink, it was not developed.
Afterwards, ink manufacturers began to use colorants that were acceptable to everyone, and in 1952, they were renamed Flexographic Process at the 14th Packaging Symposium in the United States.
In the 1970s, with the progress of the materials industry, especially the emergence of polymer resin plates and metal ceramic mesh rollers, there was a qualitative leap in the development of flexographic printing.
01
The principle of flexographic printing
When printing, the ink roller (rubber roller) in the ink tank first transports the ink to the ink roller (mesh metal roller), and then the excess ink on the surface of the mesh ink roller is removed by the ink roller. Finally, the ink is evenly and stably applied to the surface of the plate cylinder by the ink roller; When the printing material (such as plastic film) passes between the printing plate cylinder and the impression cylinder, the graphics and text on the printing plate are transferred to the printing material under pressure, thereby obtaining clear graphics and text.
02
Characteristics of flexographic printing
Strict environmental requirements
Guided by national policies and advocating for "green development", the main focus is on the way of economic development, emphasizing the coordination between economic development and environmental protection. The principles of rationality and rationality are integrated into all aspects of production and consumption, which can promote rapid economic development and protect the ecological environment. Flexographic printing itself is a green printing method that uses water-based, UV, and LED UV inks.
High production efficiency
The production speed of flexographic printing is usually above 100m/min, the production speed of satellite flexographic printing equipment is above 300m/min, and the production speed of combination printing with screen printing is 60-70m/min, far higher than the production speed of letterpress printing, intermittent offset printing and other printing methods, greatly improving production efficiency. In addition, a flexographic printing machine usually only requires 1-2 people to turn on, greatly reducing labor costs.
Reduce machine adjustment losses
With the widespread application of servo technology and intelligent control technology in flexographic printing equipment, as well as the popularity of petal shaped flexographic printing units, the adjustment time and loss cost of flexographic printing equipment have been greatly reduced.
Diversified and rapid plate making
With the application of laser digital plate making technology, film plate making has gradually exited the historical stage, and professional plate making companies have improved their plate making speed and reduced plate making costs. At the same time, with the continuous improvement of the quality of washed plate materials, the sales cost of professional laser plate making machines has also been significantly reduced. More and more label printing companies are beginning to equip their own plate making equipment and plate making, which greatly reduces the plate making time and cost (close to the cost of relief plate making), making it suitable for use in small and medium-sized orders.
Significant improvement in printing quality
The application of digital technology, flat top dot technology, the use of rubber plates, the popularization of petal shaped flexographic printing units, and the use of high line count mesh rollers have greatly improved the quality of flexographic printing. High line count printing with 175LPI/200LPI has become the standard for flexographic printing.
Lowering the investment threshold
The technology of domestic flexographic printing equipment manufacturers is constantly improving, and their sales prices are relatively cheap. More and more label printing companies are turning to invest in domestic flexographic printing equipment. At the same time, imported flexographic printing equipment manufacturers are also lowering their sales prices in order to gain more market share, significantly reducing investment costs.
Wide range of printing materials
Composite materials such as paper (whether smooth or rough), cardboard, corrugated paper, film, aluminum foil, and hoses can all be printed using flexographic printing. The range of printing materials far exceeds printing methods such as lithography, gravure printing, and relief printing.
Strong color consistency
Due to the short ink path ink transfer method used in flexographic printing, the entire printing process only includes ink transfer rollers, mesh rollers, plate rollers, and embossing rollers. Through the use of mesh rollers for ink transfer, color consistency between printed products from the same batch and different batches can be ensured.
03
Application classification of flexographic printing
According to the application field, flexographic printers are divided into label type, flexible packaging type, paper box, paper cup hard packaging type, and paper box pre printing type.
Label category
Mainly used for adhesive label printing, this type of flexographic printer has complete functions and almost includes all the wiring functions of the flexographic printer, such as peeling and compounding, flipping, hot stamping, laminating, polishing, die-cutting, waste removal, embossing, cutting, and slitting.
Soft packaging category
Soft packaging flexographic printers are mainly used for paper printing packaging materials, such as disposable medical product packaging bags, tea packaging paper, food packaging paper, non-woven fabrics, etc. If equipped with corona treatment systems, they can also print plastic films such as BOPP and PET.
Paper boxes and cups
Mainly used for printing cardboard, single and double PE paper, such as paper cups, paper bags, food packaging boxes, drug packaging boxes, etc
Pre printed cardboard boxes
Mainly used for pre printing large quantities of packaging cardboard boxes.
04
The unique characteristics of flexographic printing
① Using soft polymer resin plates not only reduces plate making costs and shortens plate making cycles compared to gravure printing, but also meets the needs of general packaging printing due to the improvement of plate manufacturing level and plate making technology.
② The use of a mesh roller, which serves as both an ink transfer roller and an ink metering roller, achieves a short ink path similar to gravure printing and can accurately supply ink according to process requirements, providing a favorable means for precise control of ink color and ink layer thickness.
③ Zero pressure printing not only reduces mechanical vibration and wear, as well as plate wear, but also expands the range of printing media, especially for the printing of flexible materials.
④ The narrow width flexographic printing machine also expands the functions of the printing machine, which can complete a large number of post press processes in addition to printing, making the flexographic printing machine a production line that integrates printing and post press processing.