Printing is not always the final stage in printing. In most cases, post-printing processing of printed products is also provided, which is used in order to protect finished products from damage as much as possible, to give them a decorative effect and a finished look.
Printing and post-press processes
All work on the production of printed products can be divided into several stages:
- Pre-print preparation (development of a layout, color proofing, preparation of printing forms - the latter is used for offset printing).
- Printing of polygraphic products.
- post-press processes.
The technology of post-press processes or post-press is a whole range of activities that is performed immediately after printing. All of them are designed to improve appearance finished products, improve their quality and strength.
Types of post-print processing
Today, there are many types of post-print processing: some are utilitarian and are necessary to ensure that the size of the finished product matches the declared one and it can fulfill its purpose with high quality, while others are decorative and are used for decoration and decoration. The most popular types of such processing are:
cutting
To ensure that the final product is the right size (printing presses are often designed for significantly larger size than necessary) use a type of post-print processing such as cutting. It is performed using special cutters (saber and guillotine). Cutting is carried out not only with a flat, but also with a curly edge and allows not only to adjust the size of the finished product to the declared one, but also to neatly shape the edge of the products.
Die-cutting/punching
Die-cutting refers to another type of post-print processing, which makes it possible to obtain finished products of the desired size. But since such processing is carried out using a special press and cliches, and not using cutters, it allows you to get products of the original form. Figured die-cutting is also often used inside rectangular-format products: this technique is popular in the manufacture of invitation cards or postcards. This treatment looks very elegant and stylish.
With the help of cutting, you can make:
Dorhengers (sizes and types of dorhengers)
Negghegners (sizes and types of negghegners)
lamination
This type of post-print processing of printed products involves covering the printed image with various films. They will not only reliably protect the finished product from damage, but also give it a more pleasant look, creating an additional effect of dullness or texture. In addition, the film will make the colors brighter and richer. With such processing, even inexpensive paper will look like designer paper.
UV varnishing
Refers to post-printing processes, the purpose of which is not only to protect the image, but also to give it additional decorativeness, to make it more attractive and interesting. A layer of varnish is applied to the image and forms a durable film, increasing the life of the product and improving its aesthetic characteristics. Varnishing can be continuous (the entire image is varnished) or selective (the coating is applied only to some areas).
Creasing / Creasing
This type of processing is used for the manufacture of products with a fold. A special machine, by punching, creates a neat path at the bend, along which bending is then performed. After such post-print processing, printed products acquire a finished look and additional strength at the fold.
Folding/Folding
This post-press process is used when a smooth fold is required without the use of a dull knife. In some cases (for example, when paper or cardboard is thick), folding without preliminary creasing is impossible. Folding can be done not only on folding machines, but also manually. In some cases (for example, if products are non-standard), manual folding is the only possible variant addition.
Folding can be done in a specific pattern, which will ensure the correct sequence of pages in a multi-page product. Most often, folding is used for the manufacture of certain types of sheet products - booklets, leaflets, invitations and tags. It is also needed for folding pages in multi-page products - brochures, catalogs, etc.
foil stamping
Such post-print processing of printed products is often chosen when the product needs to be given a festive and expensive look. Embossing is done using clichés and ink foil: an imprint is applied to a paper, plastic or cardboard base, and the foil (under the influence of high temperature) is melted and gives the stamped image a stylish and elegant look.
hot stamping
Post-press technology enables embossing different ways. Embossing is done using a hot press, which allows you to get a neat three-dimensional image without additional special effects (this technique is often used to design book covers).
Perforation
With the help of perforation - a special system of holes - you can neatly and clearly draw a tear or fold line (this is necessary for making spectacular tickets, invitations or flyers).
Corner rounding
This post-printing process allows you to give finished products a beautiful shape and a pleasant appearance (used in the manufacture of discount cards, calendars, notepads).
Piccolo setting
Such processing involves the installation of metal rings on the printed products at the attachment points, which will prevent the base from breaking. Piccolo are used in the production of calendars, tags, posters and increase the strength characteristics of finished products.
Bookbinding works
These are post-printing processes, as a result of which notebooks, magazines, catalogs, brochures, books in a cover or binding are obtained from printed individual sheets. The process includes collating, folding, binding (with a clip, spring, glue, binding) finished products and covering them with a cover.
Post-press from Printing House
Our printing house performs all types of post-print processing of printed products. Having at our disposal modern professional equipment, we not only quickly and efficiently organize the printing of any circulation of printed products, but also perform post-press, including:
- cutting (classic and curly);
- lamination and UV varnishing;
- scoring;
- stamping (blind, embossing, foil);
- perforation and rounding of corners;
- folding;
- piccolo installation;
- numbering;
- bookbinding work.
Post-press processes are an important component in the production of printed products. As the name implies, these processes include everything that happens to the product after it has left the printing press. The main post-press processes are cutting to size, folding, creasing, collating and Various types publication bindings. In addition, there are also so-called finishing operations: embossing, cutting, laminating, UV varnishing and others.
Folding and creasing
Folding refers to the folding of sheets of printed matter. Folding is carried out on special folding machines and is used in the manufacture of both sheet products (booklets) and multi-page products - to form the so-called notebooks.
Folding machine
When making multi-page products, the folding operation is often performed at the same time as collating to speed up the booklet production process.
In the case of working with thick papers or cardboards (usually more than 170 g/m2), a creasing operation is performed before folding. It consists in creating a micro-groove in the place where the fold will pass. Groove-big significantly increases the accuracy of the location of the bend; in addition, without it, on thick paper, kinks may occur when folded.
scoring usually performed on a separate creasing or folding equipment with a special knife installed on it. There are machines capable of creasing and folding the product in one pass.
Listing
Collation (booklet) in the printing process is the selection of printed or folded sheets / notebooks into blocks for their subsequent processing (stitching, gluing, etc.). Sheet collation is carried out on collating machines, which, according to the type of construction, are divided into vertical (tower type) and horizontal (flow type).
Vertical collating machine
Vertical-type machines are "tower" sections mounted on a frame. Sections can be connected to each other, as well as different modules can be connected to the machine, allowing you to perform various additional operations: stitching, trimming along the front edge, acceptance. This facilitates and speeds up the process of producing magazines and catalogs. Tower-type collating machines are convenient in small and medium-sized enterprises: they take up little space and are the most mobile. Their disadvantage is that they are not intended for the selection of folded notebooks - this is possible only on machines of a horizontal (flow) type of construction.
Horizontal collating machine
Horizontal type machines consist of many sections (4-12) plus stitching, trimming and receiving modules. This equipment is designed for large productions. They are used for long runs, single-type runs, and short runs without changing paper type and size. The downside of these machines is the large footprint and noise.
fastening
In the printing industry, two types of binding are most often used: sewing with wire (or staples) and glue (the so-called seamless).
When binding with wire, the brochure is selected sheet by sheet (ie, one spread is inserted into another), then the entire block is folded and fastened with metal clips. The entire bonding operation is usually performed in one go. This type of binding is quite economical and is used for brochures with a small number of pages (usually up to 60-80, depending on the paper weight). For thicker booklets, this type of stapling is not applicable because the resulting booklet will not close.
With adhesive bonding, the printed sheets are first folded (to obtain notebooks), and only then are they selected and glued together. In principle, it is possible to fasten brochures of any stripe in this way, but best results(with a clearly designed spine) are obtained with a stripe of at least 60 stripes. Adhesive bonding, as a rule, is more expensive than wire stitching; in addition, it has its limitations - as a rule, it is not possible to achieve a strong bonding of a block printed on thick coated paper.
Printing processes
Obtaining identical prints from the printing plate on the receiving surface is called the printing process. Printing ink is applied to the printing plate and, depending on the printing method, transfers directly or indirectly to the paper under the influence of an impression cylinder exerting pressure. In order to “smooth out” irregularities on the surface of the printing plate as much as possible, an elastic dekel is used, fixed on the printing cylinder. The role of the deckle in offset printing is performed directly by the offset cylinder itself with a rubber-fabric surface.
To obtain printing products of optimal quality great importance It has correct selection printing materials: with a decrease in the characteristics of the surface strength of paper, it is necessary to reduce the viscosity of the dyes. In media editorial offices, when preparing printed publications for an output device, it is necessary to correctly set the parameters of the pulling point, which will directly depend on the absorbency of the paper, so that the raster printed elements have a given value on the print. An error in determining the degree of paper whiteness even at the prepress stage in the production of full-color publications will lead to a distorted color reproduction of the entire print run, etc.
For each of the printing methods, certain inks and types of papers are used, all print media strive to achieve the optimal result while reducing the cost of circulation products, therefore, knowledge of the properties of printing materials, the capabilities of printing machines and the corresponding prepress characteristics are necessary for management and technical services publications of all types for successful work in a market economy.
The appearance of the oldest handwritten books dates back to the 16th century BC, and those printed by printing method - to the 9th century AD, but already at that time there were elements of post-print processing of the publication: the papyrus was rolled up in the form of scrolls, wooden covers were hollowed out for their storage , and to them, in turn, they tied plates with the name of the works - “tituluses” (Ancient Rome).
In the 1st century BC. books from a new material for that time - parchment - begin to be bound: wooden boards are used as covers, in which holes are made for ropes. Later, the boards are replaced with thick parchment, and next step development of the book, thin boards are covered with leather.
At the turn of III-II centuries BC. folding operations appear (German “to bend”) - folding a printed sheet in half - and tabs: folded sheets are inserted into each other, like paper sheets of a modern student notebook. In old handwritten books, scribes put sheets folded in half into each other. Notebooks were numbered and sewn together with thin tendons.
In the second half of the 15th century, the Italian publisher and printer Ald Manutius the Elder (c. 1450-1515), the founder of the Aldov publishing house, which had existed for almost a century, introduced book formats as a standard, with the advent of which the folding operation became more complicated:
The sheet is folded in half, that is, two pages are placed on it on one side (“in folio” format);
The sheet is folded twice, for the simultaneous arrangement of four pages on one side (“in quattro” format);
The sheet is folded three times to fit eight pages on one side (“in octavo” format).
Along with the tab of sheets into each other, a selection operation appears - sequential fastening of folded sheets. Naturally, with the advent of folding, it was necessary to master the cutting of sheets along the outer edge of the fold.
At further stages of the post-printing processing of books, the operations of fastening folded notebooks by sewing, pressing several notebooks in a wooden vice, processing the spine of the block and decorating the binding were improved.
Until the second half of the 15th century, books were sold as a set of unbound notebooks. The readers themselves bound the books according to their own tastes. For the first time in the history of printing, part of the edition was bound in the printing house of Erhard Ratdolt (1447-1528), who worked in Vienna. Further, the work of the printer and the bookbinder was divided, and even special workshops began to appear, carrying out bookbinding and bookbinding. But only in the 19th century did the mechanization of post-printing processes begin.
The modern technological chain of post-press processes in the production of printed publications depends on their type.
Newspaper - a one-time periodical sheet publication of a certain format (A2, AZ, A4) with a variety of text and illustrative materials, with a different number of unbound pages. The newspaper contains official and operational information about political, economic, cultural, etc. events in the world. The number of post-press operations during the release of a newspaper is minimal. Newsprint paper typically contains at least 85% mechanical wood pulp, which makes it brittle and yellows quickly.
Most newspapers are printed on roll-to-roll rotary presses. After the end of the printing process, newspaper products are folded (folded) and cut. Depending on the volume of newspapers, collation and insertion of printed sheets can be carried out.
A journal is a periodical publication of various formats, including a number of works of various genres, united by a common program, containing publications of socio-political, scientific, cultural, etc. nature, designed for a short period of use, having a block (sheets fastened in the spine) and a paper cover. Magazine products are printed both on roll-fed and sheet-fed presses. Depending on the type of publication, magazines can be printed on book and magazine, offset, coated, etc. paper.
post-press processes.
Post-printing processes are all those processes that occur with printed products after they have been printed. The main types of such processes include cutting, folding, creasing, fastening.
Cutting any printing products plays a significant role. For example, cutting small printed products, such as business cards, must be done with the utmost care.
Folding- this is a fold of sheets to obtain a bound notebook. The number of folds determines the number of pages in a notebook or book. For example, notebooks can have 4, 8, 16, or 32 pages.
Creasing - This is a technology for applying a straight groove on a paper sheet. The groove itself is called bigom. Creasing is recommended for folding paper with a density of more than 170 g/sq.m. The concepts of folding and creasing must be distinguished, since these processes are performed sequentially and on different equipment.
Bonding. The main types of fastening are divided into sewing with wire (staples) and adhesive (seamless). When fastening with wire, one turn of the product is inserted into another, then the folding process takes place and is fastened with paper clips. This type of bonding is used with a small number of paper strips, usually up to 60-80.
After printing sheets with adhesive bonding, they are folded, then glued together. It is sometimes impossible to achieve a strong bond of thick paper.
lamination- This is a coating of products with a transparent film. Lamination allows you to increase the life of your product.
Embossing is a process that changes the surface level of the paper through the use of a die press. Both blind (blind) embossing and foil embossing are used. This allows you to make the image three-dimensional.
Foiling is the technology of applying foil to printed products.
Post-printing processes are an important component in the production of printed products. As the name implies, these processes include everything that happens to the product after it has left the printing press. The main post-printing processes are cutting to size, folding, creasing, collation and various types of product binding. In addition, there are also so-called finishing operations: embossing, cutting, laminating, UV varnishing and others.
FOLDING AND CREATING
Folding refers to the folding of sheets of printed matter. Folding is carried out on special folding machines and is used in the manufacture of both sheet products (booklets) and multi-page products - to form the so-called notebooks.
In the case of working with thick papers or cardboards (usually more than 170 g/m2), a creasing operation is performed before folding. It consists in creating a microgroove in the place where the fold will pass. Groove-big significantly increases the accuracy of the location of the bend; in addition, without it, on thick paper, kinks may occur when folded. Creasing is usually performed on a separate creasing equipment with a special knife installed on it.
SHEET SELECTION
Collation (booklet) in the printing process is the selection of printed or folded sheets / notebooks into blocks for their subsequent processing (stitching, gluing, etc.)
Vertical type machines are sections - "towers" mounted on a frame. Sections can be connected to each other, as well as different modules can be connected to the machine, allowing you to perform various additional operations: stitching, trimming along the front edge, acceptance. This facilitates and speeds up the process of producing magazines and catalogs.
BOND
In the printing industry, two types of bonding are most often used: sewing with wire (or staples) and glue (the so-called seamless). With adhesive bonding, the printed sheets are first folded, and only then are they picked up and glued together. In principle, brochures of any stripe can be bound in this way, but the best results (with a clearly designed spine) are obtained with a stripe of at least 60 pages. Special mention should be made of a fairly new type of fastening - fastening with the Mge-O spring. This type of fastening is technologically convenient in production and is widely used in the manufacture of multi-band calendars, notepads, notebooks and other multi-page products.
STAMPING
Embossing - or applying foil to a printed product - can greatly improve the appearance of the product. Foil stamping is usually applied to representative products: diplomas, diplomas, folders, as well as to the covers of expensive representative brochures: annual reports, etc. In addition to metallized foil, a wide range of foils of different colors and shades, holographic and pigment foils are currently used. Special mention should be made of convex (embossed) embossing. This embossing, unlike the usual one, is performed using not one, but two clichés: concave and convex. In this case, you can get a result close to the sculptural (bas-relief).
LAMINATION
Lamination (or film lamination), that is, applying a film coating to printed products, has two functions. Firstly, the film protects the product, for example, from moisture or grease. Secondly, the film significantly improves the appearance of the printed product. Currently there are films various kinds(matte, glossy, holographic effect, etc.) and various thicknesses for lamination. Product covers are usually laminated with a thinner film, and products such as pocket calendars with a thicker film.
The process of forming an electrophotographic print is carried out in five stages:
1. Imaging A "latent" image is obtained on the surface of a photoreceptor using a controlled light source (this can be a laser or an LED bar). The positioning of the light signal on the photoreceptor corresponds to the image to be printed. During exposure, the charge of individual sections of the photoreceptor surface changes.
2. Applying toner
For electrophotography, special coloring materials are used, called toner. These can be powder or liquid toners, which are different in composition and contain a color pigment. The application of the toner occurs with the help of systems that ensure the transfer of small particles of toner (size from 6 to 8 microns) to the photoreceptor. Toner particles fall on the charged areas of the surface of the photo-semiconductor layer, and an image is formed. After applying the toner to the photoreceptor, the latent electrostatic image becomes visible.
3. Toner Transfer (Printing) Toner can be transferred directly to paper or to an intermediate system such as a cylinder or ribbon. In most cases, the toner is transferred directly from the photoreceptor to the printed material. Electrostatic forces are needed to transfer the charged toner particles from the drum surface to the paper. They are created by a corona discharge source with simultaneous pressing of the paper against the drum.
4. Toner fixing
In order for the toner particles to be fixed on the storage medium to create a stable printed image, the toner must be fixed to the paper. When paper with toner is heated, it melts and thereby fixes.
5. Cleaning
After transferring the image from the photoreceptor to paper, there may be residual charges and loose toner particles on the photosensitive drum. To prepare the drum for the reproduction of the next image, mechanical "cleaning" (neutralization) is necessary and, in addition, the removal of electrical charges in its individual sections. Removal of toner particles is carried out with a brush and suction. Surface charges are neutralized by a corona discharge. The drum surface will then become electrically neutral and free of toner particles. As in the first stage of the process, then the photoreceptor is charged again and the image is formed on the drum according to the original.
From the description of the processes, it becomes clear that electrophotography works without a printing plate with printed elements traditional in polygraphy. A latent electrostatic image is formed on the photoconductive layer every time an impression is to be made from the original. (For the unification of terminology, the name “imprint” is adopted instead of the used “imprint”).
Decentralization of the press. Meaning. Technology system. Centralized
publication of periodicals.
Decentralization - when the content of the newspaper is formed in the center, and the information
transferred to places where replication takes place. Centralization - vice versa:
information about the newspaper is transmitted via modem or mechanically to
central printing house, where the newspaper is printed and mechanically
is brought back.
There are 2 options for dispersing the printing of publications:
1. with the help of matrices and 2) with the help of photo telegraph equipment and communication channels.
Of course, the most efficient decentralized printing technology
publication is based on the transmission of images of printed strips via communication channels
from the center to remote areas of the country. With photographic equipment
the graphic information of a newspaper page is converted into electrical signals,
which are sent to the receiving points. There, these signals are converted into
light pulses and are sequentially recorded in the form of a latent image
on photosensitive material.
The production of printing plates using phototelegraph technology consists of
of the following processes: printing quality prints from original
newspaper forms at the transfer point, direct image transfer
strip prints via communication channels to reception points, film processing and
production of a printed form.
At the reception points from the received negative (or transparencies) of the newspaper strip
a printing plate is being prepared according to various locally accepted technologies, and
the circulation of the newspaper is printed by offset or letterpress printing. Considering compressed
the timing of the release of the newspaper, at the points of transfer and reception of newspaper pages,
high-speed reliable equipment. So, when using letterpress
forms of newspaper strips are made by emulsion etching on microzinc.
The use of laser radiation in phototelegraph equipment gives
the opportunity to receive at the reception points not the photoforms of the strips, but the finished printed
products.
Decentralization of printing is one of the effective ways to quickly
issue and delivery to readers of central newspapers and magazines. This has a great
economic and political importance.
The discipline "Technology of post-printing processes" is intended for studying by students studying in the direction 261700.62 "Technology of printing production".
With all the variety of forms of information, the printed media will continue to assert its positions in the future, while only a shift within product groups will occur. While educational and specialized literature, such as reference books, encyclopedias and dictionaries, due to the necessary modernization, multimedia forms of presentation and the ability to quickly obtain information when working on a computer, are increasingly published on CD-ROM or become available online, fiction, photo albums, guides, catalogs, brochures, magazines, etc. printed on paper. The advantages of printed products are the convenience and practicality of use, visibility and the possibility of selecting information, stimulating the reader's senses and imagination, as well as the pleasant sensation of touching the book's binding material, turning pages, smelling leather and printing ink. The advantage of books, brochures and newspapers is also their availability to the user at any place and at any time without any auxiliary technical means.
The most important criteria in the production of books, brochures and other end products continue to be increased strength (e.g. tensile strength), improved usability of the product (e.g. opening a book), reduction of variations in size, position and shape (e.g. folding). Along with this, the search for new product options to improve the efficiency and attractiveness of printed products.
Post-printing processes include the whole range of operations for processing printed sheets into finished printing products. Postpress processes combine the binding and finishing processes.
Stitching processes- This is a complex of operations for turning printed sheets into book blocks.
Bookbinding processes is a complex of operations for the processing of book blocks and the manufacture of covers and binding covers.
Recently, customers of printing products have begun to attach more and more importance to the quality of its finish. Finishing of printing products they call the processes of finishing, improving operational properties (wear resistance, water resistance, etc.), protective properties.
In connection with the above, the objective of this course is to provide students with a body of knowledge about the methods of processing printed materials into finished products.
To master the discipline "Technology of post-press processes" it is necessary that the student possess the skills acquired in the study of pre-press and printing processes.
As a result of studying the discipline, the student must:
1) know:
The entire technological sequence of the production of book and magazine products;
Appointment of technological operations for the processing of book and magazine products;
Types of binding covers and covers;
Types of endpapers, illustrations and ways of attaching them to notebooks;
Ways of fastening book and magazine products;
Methods for inserting book blocks into binding covers and covers;
Factors affecting the quality of semi-finished products and finished products;
Types of finishing of printing products;
2) be able to:
Choose a technological scheme for the production of book and magazine products;
Choose types of endpapers, types of binding covers and covers for a particular publication:
Perform the necessary calculations of the details of binding covers;
Assess the quality of semi-finished products at various stages of the production of book and magazine products and finished products;
Correctly choose technological modes when finishing printing products;
Use scientific, technical and reference literature.
In the process of mastering this discipline, the student must be competent in:
Formation of ideas about the methods of production of printing publications, advertising, souvenir and display products, packaging and label products, as well as products of the electronic industry, using post-printing processes, the characteristics and design of printing and packaging products and the equipment used;
Mastering the methods and means of processing printed paper and other materials in the process of post-press production;
Mastering professional terminology in the field of printing and packaging industries.
