Printing is a process for reproducing text and image, typically with ink on paper using a printing press. It is often carried out as a large-scale industrial process, and is an essential part of publishing and transaction printing.
Modern Printing Technology
Across the world, over 45 trillion pages (2005 figure) are printed annually. In 2006 there were approximately 30,700 printing companies in the United States, accounting for $112 billion, according to the 2006 U.S. Industry & Market Outlook by Barnes Reports. Print jobs that move through the Internet made up 12.5% of the total U.S. Printing market last year, according to research firm InfoTrend/CAP Ventures.
Books and newspapers are printed today using the technique of offset lithography. Other common techniques include:
Flexography:Flexography (also called surface printing), often abbreviated to flexo, is a method of printing most commonly used for packaging (Labels, Tape, Bags, Boxes, Banners, Etc).
A flexo print is achieved by creating a mirrored master of the required image as a 3D relief in a rubber or polymer material. A measured amount of ink is deposited upon the surface of the printing plate (or printing cylinder) using an anilox roll. The print surface then rotates, contacting the print material which transfers the ink.
Originally flexo printing was basic in quality. Labels requiring high quality have generally been printed Offset until recently. In the last few years great advances have been made to the quality of flexo printing presses.
The greatest advances though have been in the area of PhotoPolymer Printing Plates, including improvements to the plate material and the method of plate creation. —usually photographic exposure followed by chemical etch, though also by direct laser engraving.
Digital Direct to Plate systems have dominated the industry recently with their incredible quality and ability to print four color process as well as Offset. Companies like Dupont in DE and PlateCrafters in Colmar, PA have pioneered the latest technologies with advances in FAST washout and the latest screening technology, even companies who make plates in house are going to trade shops to get these high quality plates.
Laser-etched anilox rolls also play a part in the improvement of print quality. Full color picture printing now occurs, and some of the finer presses available today in combination with a skilled operator allow quality that rivals the lithographic process. One ongoing improvement has been the increasing ability to reproduce highlight tonal values, thereby providing a workaround for the very high dot gain associated with flexo print.
Flexo has an advantage over lithography in that it can use a wider range of inks and is good at printing on a variety of different materials. Flexo inks, like those used in gravure and unlike those used in lithography generally have low viscosity. This enables faster drying and, as a result, faster production; that means low cost. Printing press speeds of 450 meters per minute are regular with modern technology high end printers, like Windmoeller und Hollscher or Schiavi type. The main printing process worldwide for flexible packaging are rotogravure, for very large runs, and flexo for large and medium runs.
Typical products printed using flexography include brown corrugated boxes, flexible packaging including retail and shopping bags, food and hygiene bags and sacks, flexible plastics, self adhesive labels, and wallpaper. A number of newspapers now eschew the more common offset lithography process in favour of flexo.
Relief Print:A relief print is an image created by a printmaking process, such as woodcut, where the areas of the matrix (plate or block) that are to show printed black (typically) are on the original surface; the parts of the matrix that are to be blank (white) having been cut away, or otherwise removed. Printing the image is therefore a relatively simple matter of inking the face of the matrix and bringing it in firm contact with the paper; a printing-press may not be needed as the back of the paper can be rubbed or pressed by hand with a simple tool.
Screen Printing:Screenprinting, silkscreening, or serigraphy is a printmaking technique that creates a sharp-edged image using a stencil. A screenprint or serigraph is an image created using this technique.
Rotogravure:Rotogravure is mainly used for magazines and packaging.It is a type of intaglio printing process, in that it involves engraving the image onto an image carrier. In gravure printing, the image is engraved onto a copper cylinder because, like offset and flexography, it uses a rotary printing press. The vast majority of gravure presses print on reels of paper, rather than sheets of paper. (Sheetfed gravure is a small, specialty market.) Rotary gravure presses are the fastest and widest presses in operation, printing everything from narrow labels to 12-feet-wide rolls of vinyl flooring. Additional operations may be in-line with a gravure press, such as saddle stitching facilities for magazine/brochure work.
Inkjet:Inkjet is used typically to print a small number of books or packaging, and also to print a variety of materials from high quality papers simulate offset printing, to floor tiles. Inkjet is also used to apply mailing addresses to direct mail pieces.Inkjet printers are a type of computer printer that operates by propelling tiny droplets of liquid ink onto paper. They are the most common type of computer printer for the general consumer due to their low cost, high quality of output, capability of printing in vivid color, and ease of use.
Dye Transfer:The dye transfer process is a continuous-tone color photographic printing process, popularized by the Eastman Kodak Company in the 1940s. It is sometimes referred to by such generic names as wash-off relief printing and dye imbibition transfer printing. The process involves making three matrices for each color, which absorb dye in proportion to the density of the relief. A color print is formed, by transferring the dyed film matrices in physical contact onto a mordanted dye receiver paper. Eastman Kodak Company stopped making materials for this process in the mid 1990s. The dyes used in the process are very spectrally pure compared to normal coupler induced photographic dyes, with the exception of the Kodak cyan. Also the dyes have excellent light and dark fastness. The dye transfer process posses the largest color gamut and tonal scale than any other process, including inkjet. Another important characteristic of dye transfer is it allows the practitioner the highest degree of photographic control compared to any other photochemical color print process
Laser Printing:Laser Printing is mainly used in offices and for transactional printing (bills, bank documents). Laser printing is commonly used by direct mail companies to create variable data letters or coupons, for example.A laser printer is a common type of computer printer that rapidly produces high quality text and graphics on plain paper. Like photocopiers, laser printers employ a xerographic printing process but differ from analog photocopiers in that the image is produced by the direct scanning of a laser beam across the printer's photoreceptor.
Pad Printing: Pad Printing for applying a flat image on a curved substrate.Pad Printing is sometimes also called "Tampo" or "Tampo Printing".Pad printing is used for decorating products in many industries including medical, automotive, promotional, apparel, electronics, appliances, sports equipment and toys. It can also be used to deposit functional materials such as conductive inks, adhesives, dyes and lubricants.