The world of printing is ever evolving. To give you a head start, here is a run through of what the major printing technologies can do for you:
Whenever excellent quality is needed, offset is the preferred choice. Thanks to modern servo machines, the high degree of standardisation, low plate costs, and a beneficial cost per label, offset is used more and more, also for relatively simple labels. A modern servo machine is able to reduce setup times and waste significantly. In the last few years these improvements have been so significant that often offset is now able to efficiently compete with flexo printing.
Additionally, substrates are influencing the choice of the main printing process as well. In particular, textured substrates in the wine industry are restricting flexo. Because of the low ink laydown, offset is preferred for all wrap and shrink applications too.
Offset is extremely good in CMYK and vignette printing, and has a reputation as a high quality printing process. The technology gives outstanding results in the light and dark areas. Offset has low dot gains, like the new advanced flexo presses, but the size of the minimal dot in offset can be virtually zero. Offset is second best in solids; for that reason 95 percent of all offset presses are combination machines with offset and flexo.
Offset printing plates are quite inexpensive to produce and do not have raised images; dot gain, therefore, is virtually nonexistent.
There are two segments for typical offset labels. First, non-combination labels in long runs: detergent, under-the-sink products, some high-end food. Second, combination requesting products: H&B, cosmetics, wine. Here the offset is used for very fine process combined with flexo, screen, gravure and foiling for adding value to the design and shelf appearance. Good examples are wines from the New World plus Italy, as well as high-end personal care products like Pantene, Dove, Fructies, and Herbal Essence.
Offset combination quality is still a way to differentiate from your competition. At Nilpeter, we manufacture offset and combination presses, such as the MO-4, that can utilise offset, UV-flexo and a variety of print processes. Designed specifically for products of uniform quality, the Nilpeter MO-Line is the natural choice for printing companies that supply global players demanding only the best. Featuring the latest technology, MO-presses are suitable for long, medium, and short runs, handling the complete wide range of substrates.
Flexo printing is the common name for the flexographic printing process, and it is used for a number of purposes in packaging, including label printing. It utilises flexible relief plates, and can be used for printing on almost any type of substrate, including polymer films, metallic films, and paper. The flexo process is also well suited for printing large areas of solid colour.
Typical products printed using flexography include corrugated carton boxes, flexible packaging including retail and shopping bags, food and hygiene bags and sacks, milk and beverage cartons, flexible plastics, self adhesive labels, disposable cups and containers, envelopes and wallpaper. Flexographic printing can be used for a range of materials, requires only short print preparation times, is low-cost, and delivers clean prints.
In general terms, flexo printing employs a flexographic plate (made of polymer or rubber) with a raised image or text that is attached to a cylinder.
There are three major types of inks used in flexo printing: water-based, solvent-based and UV-curing inks. Flexographic inks generally have a low viscosity, which enables faster curing and, as a result, faster production and lower costs. For label printing the process uses different types of flexible polymer plates with a backing layer, a light-sensitive relief layer, and a protective film coating. After a prepress process, the plates are mounted on a sleeve or print cylinder using a plate mounting tape. The required image can also be engraved directly on printing sleeves.
Labels requiring high quality have generally been printed using the offset process until recently. However, great advances have been made to the quality of flexographic printing presses, printing plates and printing inks. The greatest advances in flexographic printing have been in the area of photopolymer printing plates, including improvements to the plate material and the method of plate creation. Label flexographic presses are capable of producing high quality impressions on many different substrates and is the least expensive and simplest of the printing processes used for decorating and packaging printing. The use of flexographic printing is on the rise, thanks to relatively simple operations, and the ability to use water-based inks, which means a large reduction in VOC emission in the printing process. Modern flexo presses are focussed on reducing cost of setup.
Digital printing has grown significantly over the past few years due to substantial developments in quality and sheet sizes. While there are a number of digital printing processes, UV-inkjet is the one that stands out.
Digital printing of labels offers significant time saving advantages. As the print goes from concept to electronic file to substrate, there is no need for an intervening step of making some form of plate that will make the impression. This is becoming increasingly valuable as runs and turnaround times get shorter. One of the great advantages of UV-curable inks is that it separates the ink solidification process after printing from the risk of drying in the nozzles. This enables quick curing after printing with good reliability of the print head.
Nilpeter sees UV-inkjet as the future-proof technology. It is quite simply the easiest solution for a printer to handle and operate. PANORAMA, our true industrial print concept, combines high quality digital printing with conventional printing and converting. Based on industrialised platforms, it is designed for heavy duty production, and can be combined with flexo printing as well as all embellishment features.
In gravure printing, an image is etched on the surface of a metal plate or cylinder, recessing the image to be printed. The recesses are then filled with ink, while the raised (non-printing) part of the plate or cylinder is wiped or scraped free of ink. The substrate is pressed against the inked plate or cylinder and the image is transferred.
Gravure can produce fine, detailed images and can be used for short and long run printing. It can be used for CMYK printing with each colour of ink applied with its own plate or cylinder with drying steps in between.
In label printing, gravure is commonly used as a value-adding option in combination with offset or flexo. It can produce metallic inks combined with foiling solutions, and provides opaque printing of base colours. Gravure printing offers decorative and protective options.
Screen printing is the ideal process when high coverage and colour strength are required to achieve brilliant, high-grade pictorial effects. Traditionally, screen printing was used for opaque white – and while that is still an important application, the number of applications has increased.
Today it is common to see screen applications used in both fine arts and in commercial printing. Screen printing’s versatility is evident in how it allows for printing on substrates of any shape, thickness and size. Also, a greater thickness of the ink can be applied to the substrate than is possible with other printing techniques, allowing for the creation of effects such as tactile and Braille, matte and gloss effects, glitter, scratch offs, and raised text. Gold and silver screen inks are also used in lieu of foil.
The process consists of three elements: the screen, which is the image carrier; the squeegee; and ink. In rotary screen printing, the screen is formed into a cylinder. The squeegee is mounted in a fixed position inside the screen cylinder. As ink is introduced onto the squeegee, the cylinder rotates and the ink is pushed out of the screen onto the moving substrate. The printable image is created on the screen through exposure of the image in prepress. Unexposed screens contain a coating through which ink will not pass. Exposure and subsequent washout removes the coating from the image area, through which the ink will pass.
In the label industry, converters can incorporate screen print units into existing presses, and rotary screen printing can be combined with other printing techniques, i.e. flexo, offset, and gravure.
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