Selection and justification for the choice of basic materials for the post-printing process. Moscow State University of Printing Postpress Technologies

Post-printing processes include a very wide range of methods and equipment for finishing printed products. As hundreds of years ago, the most complex of them is the technological process of making a book. However, the onset of electronic media has led to a decline in the circulation of books and magazines almost all over the world. Due to the redistribution of circulation volumes towards advertising products, those methods of finishing printed products that are mainly used in advertising activities will be considered below.

Varnishing

Applying varnish to the surface of the print not only gives it additional elegance, but also increases the contrast of the image. Varnishing looks especially advantageous on matte coated paper. In addition, varnishing products such as pocket calendars protects them from mechanical stress and significantly extends their life. Of particular interest to advertising specialists is selective varnishing - the application of varnish to individual areas of the image, which significantly expands the visual capabilities of the print.

Varnish is applied in several ways. For continuous and selective varnishing, special varnishing sections are used, built into multi-section printing machines. You can also use the offset printing unit for this purpose by turning off the dampening unit. Using screen printing for selective varnishing allows you to obtain a thick (up to 100 microns) layer of varnish.

One of the latest advances in this area is UV-curing varnish. It is a composition sensitive to the ultraviolet part of the spectrum. One of its features is almost instantaneous hardening when exposed to UV radiation. In this case, the varnish does not have time to be absorbed into the paper, which increases the thickness of the varnish layer. Another feature is the hardening of the varnish due to polymerization, and not due to the evaporation of the substances contained in it. Therefore, the varnish layer is thicker than that obtained by other methods.

Applying varnish in a printing machine allows this operation to be carried out at printing speed, which significantly increases the speed of production of printed products.

Film pressing (lamination)

A special thermoplastic polymer film (laminate) is pressed onto the surface of the print with a hot roller, which slightly melts under the influence of temperature. For pressing, lavsan, polypropylene, triacetate, and diacetate films are used. Depending on the material, the film thickness varies from IS µm to 50 µm. After cooling, the film bonds firmly to the surface of the paper. This film creates the same effect as a solid varnish. However, this process is slower than applying varnish. In addition, products with lam and pat applied appear rougher in appearance. The main advantage of the film is its strength, so it is used for products that are subject to increased aggressive influences, for example, in the manufacture of covers, for softcover books. There are devices for laminating printed materials up to several meters wide, which are actively used in outdoor advertising.

Foil stamping

A thin layer of metal foil is applied to the surface of the print. Foil for embossing is available in several types: metallized, colored (matte or glossy) and bronze. Based on appearance, it is divided into “gold”, “silver”, “bronze” and colored foil. None of these metals are used to make foil. Aluminum is used to make foil. Foil consists of several layers. The basis is a temperature-resistant polymer film (polyethylene terephthalate, also called lavsan). A low-melting wax-based separating layer binds the varnish layer and the base. A layer of molten aluminum is applied to the varnish layer in a high vacuum by spraying. Its thickness is 0.02-0.05 microns. An adhesive layer is applied on top of the metal layer.

Depending on the color of the varnish layer, the foil takes on one of the indicated colors. If the varnish has a neutral color, then the foil takes on the natural color of aluminum - silver.

Under normal conditions, the layers of foil are firmly bonded to each other. But under the influence of temperature (80-150°C), the separating layer melts and the adhesive layer softens. If you apply some pressure, the aluminum layer along with the varnish will separate from the base and stick to the material being printed.

The varnish layer, which after embossing appears on top of the metal layer, not only gives the required color, but also increases its resistance to mechanical stress.

For foil stamping, metal letterpress forms are used. Attempts to use photopolymer heat-resistant materials for these purposes did not give good results due to their low thermal conductivity. To make cliches, engraving machines are used, in which the cutting tool (cutter or micro-mill) is controlled by a computer. With the help of these devices, the preparatory process is significantly reduced.

For small runs (up to several thousand copies), small semi-automatic presses are used. When printing large quantities, embossing is done using rotary presses, in which pressure and temperature are created by a heated shaft.

19.4. Carving

This type of finishing not only increases the attractiveness of printed products (pocket calendars), but also increases their security against counterfeiting (labels). In advertising, most POS materials are produced using die cutting. In particular, wobblers, stickers, posters, mobiles, garlands and other products have a figured outline, which is obtained using a stamp. A die-cutting die is used as a working tool. As a rule, it is made of thick plywood, in which a slot is cut using a jigsaw or laser according to the cut-out contour. A knife curved along the contour of the slot is inserted into the slot. Often, when making boxes or wobblers, it is necessary not to cut off the material, but to bend it (creasing). In order to mark the place of the bend, an operation called scoring is used. This is done using so-called scoring knives. They are slightly lower than die cutters and do not cut, but crumple the material. In the case of brittle material, creasing allows you to get a neat crease.

In Fig. Figure 19.1 shows a wobbler made using die cutting.

Rice. 19. 1. Wobbler made using die cutting

A type of carving is punching (or undercutting). This operation is used for processing self-adhesive materials. It consists of cutting through the top layer of material and leaving the anti-adhesive backing intact. The unnecessary part of the material, called flash, is removed and only the label remains on the release backing. Next, the substrate with the finished labels is wound into a roll and delivered to the customer in this form.

In flexographic printing machines, die-roll sections are installed, in which the stamp is a steel cylinder, on the surface of which the outline of the die-cut label is cut out using milling.

Thermography

Finishing printed images with a special thermal powder that increases the relief of the print under the influence of thermal radiation is called thermography. Another name for this method is thermal raising. After heat treatment, the image turns out to be embossed with a metallic tint to the paint layer.

Thin lines in the image and strokes of text on the print are continuous in thickness and have smooth edges, and the joints and intersections of lines are roughened and rounded.

There are special devices that apply thermal powder to the print. But the easiest way to get thermal lift is to pour a thin layer of thermal powder onto the print immediately after printing, before the ink has had time to dry. Then shake off the excess thermal powder and place the print in the oven.

Self-test questions

1. What is the purpose and scope of varnishing?

2. What is the purpose and scope of film pressing?

3. Name the materials and devices used for foil stamping.

4. What is the purpose and scope of die cutting? Tell us about the use of this finishing method in the production of promotional products?

5. What is the purpose and scope of thermography?

Brief conclusions to section V

Advertising technologies widely use printed materials: from leaflets and booklets to outdoor advertising. Printed products go through three stages of preparation: pre-press, printing and post-press. Each of them has a significant impact on the final result.

The basis of modern pre-press processes - a computer - allows you to prepare a publication, making maximum use of the capabilities of one or another printing method, which is especially important when producing advertising, usually bright and colorful, products

Image reproduction is carried out by several main printing methods, each of which has its own characteristics that must be taken into account when developing advertising products. Post-printing processes make it possible to give the print additional expressiveness, which is especially important for advertising printed materials.

1. Bukovetskaya, O. A. Text design: font, effects, color: 2nd ed., revised. M.: DMK, 2000.

2. Vodchits, S.S. Aesthetics of book proportions: textbook. allowance. M.: Publishing house MSTU, 1997.

3. GOST 3489.1-71. Typographic fonts (on Russian and Latin bases). Grouping. Indexing. Font line. Capacity. M.: Standards Publishing House, 1971.

4. Karov, L. Font technologies. Description and tools: trans. from English M.: Mir, 2001.

5. Kiphan, G. Encyclopedia of Printed Media. M.: MGUP. 2002. p. 1252.

6. Kleper, M.L. A practical guide to digital printing. Volume 1.: trans. from English M. Williams Publishing House. 2003.

7. Composition of publications. Features of designing various types of publications: textbook. allowance. - M.: Publishing house MGUP, 2000.

8. Krichevsky, V. Typography in terms and images: in 2 volumes. M.: Slovo, 2000.

9.Litunov, S. N. Screen printing technology: textbook. allowance /
S. N. Litunov, S. A. Shcheglov. Omsk: Omsk State Technical University Publishing House, 2004. 176 p.

10.Polyansky, N. Fundamentals of printing production. M.: Book,

11.Ruder, E. Typography: Design Guide: trans. with him. M.: Book, 1982.

12. Samarin, Yu. N. Prepress equipment: design and calculation: textbook for universities / Moscow. state University of Printing. M.: MGUP, 2002. 540 p.

14. Sysuev, I. A, Typography and computer font technologies: textbook. allowance. Omsk: Omsk State Technical University Publishing House, 2004.

15. Williams, R. Non-design book about fonts. SPb.: Publishing house "VES", 2003.

16. Faiola, E. Fonts for printing and Web design. St. Petersburg: BHV-Petersburg, 2003.

17. Felici, J. Typography: font, layout, design / trans. from English and comment. S. I. Ponomarenko. St. Petersburg: BHV-Petersburg, 2004.

18. Shmeleva, A. Classification of fonts: practice and problems // Publish. No. 1. 2003. pp. 78-82.

19. Shahkeldyan, B.N. Printing materials / B. N. Shakhkeldyan, L. A. Zagarinskaya. M: Book, 1988. 328 p.

20. Offset printing machines: textbook. allowance / V. I. Shtolyakov, A. F. Fedoseev, L. F. Zirnzak. M.: Publishing house MGUP, 1999. 216 p.

DIRECTING ADVERTISEMENTS

The discipline “Technology of Post-Printing Processes” is intended for study 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 position in the future, but only a shift will occur within product groups. 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, guidebooks, catalogs, brochures, magazines, etc. are printed on paper. The advantages of printed products are the convenience and practicality of use, clarity and the ability to select information, stimulation of the reader’s senses and imagination, as well as the pleasant feeling of touching the book’s binding material, turning the pages, the smell of leather and printing ink. The advantage of books, brochures and newspapers is also their availability to the user anywhere 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. book opening), reduced deviations in size, location and shape (e.g. folding). At the same time, new product options are being sought to improve the efficiency and attractiveness of printed products.

Post-printing processes include the entire range of operations for processing printed sheets into finished printed products. Post-press processes combine bookbinding and finishing processes.

Stitching processes is a set of operations to transform printed sheets into book blocks.

Bookbinding processes is a complex of operations for processing book blocks and producing covers and binding covers.

Recently, customers of printed products have begun to attach increasing importance to the quality of their finishing. Finishing of printed products are called finishing processes, improving performance properties (wear resistance, water resistance, etc.), and protective properties.

In connection with the above, the objective of this course is to provide students with a body of knowledge about methods for processing printed materials into finished products.

To master the discipline “Technology of post-press processes” it is necessary that the student possesses 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 manufacturing book and magazine products;

Purpose of technological operations for processing book and magazine products;

Types of binding covers and covers;

Types of endpapers, illustrations and methods of attaching them to notebooks;

Methods of binding book and magazine products;

Methods for inserting book blocks into bindings and covers;

Factors affecting the quality of semi-finished and finished products;

Types of finishing of printed products;

2) be able to:

Select a technological scheme for the production of book and magazine products;

Select types of endpapers, types of binding covers and covers for a specific publication:

Perform the necessary calculations of the details of binding covers;

Assess the quality of semi-finished products at various stages of production of book and magazine products and finished products;

Correctly choose technological modes when finishing printed products;

Use scientific, technical and reference literature.

In the process of mastering this discipline, the student must be competent in:

Formation of ideas about methods of production of printed publications, advertising, souvenir and display products, packaging and label products, as well as products of the electronics industry, using post-printing processes, characteristics and design of printing and packaging products and the equipment used;

Mastering methods and means of processing printed paper and other materials in the post-printing process;

Mastering professional terminology in the field of printing and packaging production.

Post-printing processes are an important component in the production of printed products. As the name implies, such processes include everything that happens to the product after it comes out of the printing press.

The main post-printing processes are cutting into formats, folding, creasing, collating and various types of binding of publications. In addition, there are also so-called finishing operations: embossing, cutting, lamination, UV varnishing and others.

Folding and Creasing

Folding refers to the folding of sheets of printed materials. Folding is performed on special folding machines and is used in the production of both sheet products (booklets) and multi-page products - to form so-called notebooks.

When producing multi-page products, the folding operation is often performed simultaneously with collating to speed up the brochure production process.

When working with thick papers or cardboards (usually more than 170 g/m2), a creasing operation is performed before folding. It consists of creating a micro-groove in the place where the fold will go. The groove-big significantly increases the accuracy of the bend location; in addition, without it, kinks may occur on thick paper when folded.

Folding machine.

Some types of folds when folding.

Leaf selection

Sheet collation (stitching) in the printing process is the selection of printed or folded sheets/notebooks into blocks for their subsequent processing (stitching, gluing, etc.). Sheet picking is carried out on sheet-picking machines, which, according to the type of construction, are divided into vertical (tower type) and horizontal (flow type).

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 for various additional operations: stitching, cutting along the leading edge, receiving. This facilitates and speeds up the process of producing magazines and catalogues. Tower-type sheet-collecting 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 designed for selecting folded notebooks - this is only possible on horizontal (in-line) type machines.

Horizontal type machines consist of many sections (4–12) plus stitching, trimming and receiving modules. This equipment is intended for large productions. They are used to produce long runs, runs of the same type and short runs without changing the type and size of paper. The downside of these machines is their large footprint and noise.

Creasing is usually performed on separate creasing or folding equipment when a special knife is installed on it. There are machines capable of scoring and folding the product in one run.

Vertical type sheet-gathering machine.

Horizontal type sheet-gathering machine.

Bonding

In printing, two types of fastening are most often used: sewing with wire (or paper clips) and adhesive (the so-called seamless).

When binding with wire, the brochure is selected sheet by sheet (that is, one spread is inserted into another), then the entire block is folded and fastened with metal staples. The entire bonding operation is usually performed in one step. This type of binding is quite economical and is used for brochures with a small number of stripes (usually up to 60–80, depending on the paper density). For thicker brochures, this type of binding is not suitable, as the resulting brochure will not close.

With adhesive binding, the printed sheets are first folded (to form notebooks), and only then selected and glued together. In principle, brochures of any stripe can be stapled in this way, but the best results (with a clearly designed spine) are obtained with a stripe of at least 60 stripes. Adhesive bonding is usually more expensive than wire stitching; In addition, it has its limitations - as a rule, it is not possible to achieve strong bonding of a block printed on thick coated paper.

Special mention should be made of a fairly new type of fastening - spring fastening (Wire-O®). Strictly speaking, this name is not entirely accurate, because... the spiral connecting the sheets is not closed.

This type of binding is technologically convenient in production and is widely used in the manufacture of multi-page calendars, notepads, notebooks and other multi-page products.

Seamless binding machine.

Wire-O® Spring Binding Machine.

Embossing

Foil stamping machine.

Embossing - or applying foil to a printed item - can significantly improve the appearance of the item. Embossing is usually applied to representative products: diplomas, certificates, folders, as well as on the covers of expensive representative brochures: annual reports, etc.

In addition to metallized foil, a wide range of other types are currently used: foil of different colors and shades, holographic foil, diffraction foil and others.

Special mention should be made of convex (embossed) embossing. This embossing, unlike the usual one, is performed using not one, but two clichés: concave (“matrix”) and convex (“matrix”). In this case, you can get a result close to a sculptural one (bas-relief). Embossing is performed both with foil and without foil. The last variety is called “blind embossing”.

Lamination and varnishing

Lamination (or film pressing), that is, applying a film coating to printed products, has two functions. Firstly, the film protects the product, for example, from moisture or from grease left by the fingers of those who use this product. The last example may seem insignificant, but in fact, this problem can be quite serious: for example, if the product is sealed in a dark color, fingerprints can significantly deteriorate its presentation qualities. Secondly, the film significantly improves the appearance of the printed product.

Currently, there are different types (matte, glossy) and different thicknesses of lamination film. Covers of products are usually laminated with a thinner film, and products such as pocket calendars are laminated with a thicker one.

Varnishing (in this case we are talking about varnishing with UV varnish) also refers to finishing operations. First of all, screen UV varnishing has fairly good visual properties (thick layer of varnish; even, bright shine). This is a rather expensive type of finishing, both due to the high cost of consumables and due to the relatively low productivity of the equipment.

As a continuous cover of a publication page, lamination is obviously more advantageous than UV varnishing in all respects, including price. Therefore, UV varnishing is mainly used for selective varnishing, for example coating photographs or parts of an image.

Laminator - a machine for pressing film.

Development of a technological scheme for the post-printing process

Figure 9.1 - Technological diagram for the production of a publication with cover type No. 2

Selection and justification for the choice of basic materials for the post-printing process

Glue selection

Glue is used to attach the book block to the cover. For reference literature that is intended for long-term use, the strength of the connection between the block and the cover is very important, so the main criterion when choosing an adhesive was the strength of the adhesive.

Adhesives can be of natural origin or synthetic. Adhesives of natural origin are divided into adhesives of plant and animal origin. glues of animal origin are too expensive for this type of publication.

Among plant-based glues, the most suitable are starch and dextrin glue. Dextrin glue. Penetrates shallowly into the material being glued, so starch glue was chosen. It consists of 10% starch, 2% dextrin, 0.14% borax and 87.6% water. However, since this glue has a slight stickiness, it is subject to alkaline treatment. When alkali acts on starch, the following changes occur: solubility increases and stickiness increases to 16 kg/cm2. The glue is prepared by mechanical stirring in cold water. The advantages of such glue are that the stickiness increases, the gluing density increases, and the working properties are maintained for 5 days. It is traditionally used to seal the spine of a bound book block, so it is most suitable for this publication.

Thus, alkaline starch glue was chosen for gluing the spine.

Thread selection

Threads were chosen as the material for the notebook fastening of the block, which is used for this type of cover. For stitching production, two types of sewing threads are used: nylon and cotton. For the designed edition, nylon threads were chosen. Their advantages are that nylon threads are stronger, rarely break when sewing, and in the spine of a stitched block they cause less thickening compared to cotton threads, which is very important for the designed publication, as it will reduce its volume.

Thus, sewing nylon threads were chosen to fasten the block.

Description of the technology for post-printing processing of the designed publication

Since a roll printing machine was used in the production of the publication, the first stage of the post-printing process involves cutting the roll.

Then the sheets are folded into four-fold 32-page notebooks in a perpendicular manner. Folding is one of the most important stitching operations during post-print processing of prints. The quality of sheet folding largely depends on such technological factors as thickness, paper volume, its humidity, the direction of the paper fibers relative to the fold, the number of folds in the notebook and the folding option.

Then the folded notebooks are selected in the required order by machine, and a book block is formed from them.

For covers, in addition to cutting and folding, a creasing operation is performed - pressing a groove on the sheet for its subsequent folding. Creasing is performed to increase the openability of the publication.

There are several methods of fastening: seamless glue, wire sewing, thread sewing, combined fastening. Modern equipment is designed for notebook and block sewing (saddle stitch and tucking). In the latter case, the sheets or notebooks of the book block are stapled together. For this type of cover, notebook sewing of the block with threads was used, which is determined by the type of publication, the number of pages and the specified type of cover.

Thread sewing is the oldest, most reliable and prestigious type of sewing. This type is characterized by the strength of the fastening of sheets, both thick and thin, and ensures good block opening and durability of the publication.

The strength of thread stitching depends on the type of sewing, the strength of the paper, the volume of notebooks, the type of thread, the number and length of stitches, and the size of the spine material. Sewing can be done with simple or adjustable brochure stitches, and for bound publications - with simple or adjustable binding stitches. Simple brochure stitches were used for binding. According to the format of the designed publication, the number of stitches is 6. A diagram of such fastening is shown in Fig. 9.2.

Figure 9.2 - Simple brochure stitch

After sewing, it is necessary to attach the book block to the cover.

The design of the cover type No. 3 is shown in Fig. 9.3. The number 1 marks the cover; 2 - block, 3 - adhesive layer.

Figure 9.3 - Scheme of cover with inflow

For this type of cover, bonding occurs along the surface of the spine using glue.

After binding, the book block is trimmed on three sides and packaged in packs of 10 pieces.