уч[1].пособие по полиграфии_final. Л. В. Красильникова английский язык для полиграфистов
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Web-fed Offset Printing Web-fed offset presses are production flow lines where the product is also a means of transportation. Web offset presses are usually categorized into either press types operating on the heatsetprinciple for the production of commercial print jobs, magazines, and publications or newspaper offset presses operating on the coldsetprinciple. A printing coupleis the single component used to print ink on one web or sheet side characterized by a plate cylinder and a blanket cylinder (couple) with associated dampening and inking units, whereas a printing unitin web offset printing is composed of several printing couples combined into one closed unit. The simplest version of a printing unit is the vertical blanket-to-blanketone which uses a horizontal web-lead to print one color on the front and reverse side of the web. The printing section is composed of two printing couples arranged in tandem. In newspaper printingunits are arranged more often horizontally than in the vertical because multi-web production is most widely used and it is easier to gather the individual color-printed sections in a vertical line before the individual webs are merged horizontally. ESSENTIAL VOCABULARY Words and Word Combinations
ACTIVITIES 1. Find words and word combinations of the essential vocabulary in the text and translate the sentences they are used in into Russian. 2. Answer the following questions:
3. Match the definition with the term:
4. Fill in the gaps with the words of the essential vocabulary:
principles. 5. Translate the sentences into English: Существуют два основных вида офсетной печати: листовая и рулонная. Листовые печатные машины печатают на бумаге, предварительно разрезанной на листы. Листовые офсетные машины могут быть одно-, двух-, четырех- или даже двенадцати-красочные. По построению они могут предназначаться для односторонней и двусторонней печати. Машины односторонней печати запечатывают только одну сторону за один прогон листа через машину. В мире коммерческой печати большая часть рулонных машин является машинами двусторонней печати. При спуске полос для печатания со своим оборотом, печатный лист делится на две половины - правую и левую. На одной половине листа, например, на правой, печатается лицо, на левой – оборот. Получается, что лицо и оборот оказываются на одной стороне печатного оттиска. Когда одна половина листа отпечатана, печатник поворачивает листы и печатает оборот, не меняя печатную форму. При этом оборот листа оказывается на месте уже отпечатанного лица. При спуске полос для печатания с одной формы печатный лист также разделяют на две половины – переднюю и заднюю. Печатный лист переворачивается для печати лица и оборота на одной стороне. Затем листы переворачиваются от “головы” к “хвосту”, чтобы печатать оборотную сторону с той же печатной формы. Боковая направляющая остается той же самой, но поле захватов меняется. 6. Match the two halves of the phrases:
7. Correct the jumbled sentences:
8. Agree or disagree with the following statements:
10. Study some examples of the phrasal verbs. Translate them into Russian. A “phrasal verb” (sometimes called a two-part verb) is a fixed expression that consists of a verb followed by an adverb (to give out) or a preposition (to look after), or sometimes both (to put up with). Phrasal verbs have their own special meanings, and these are often quite different from the meaning of the main verb from which they are formed. to throw away to polish off/ up to hand in to pick on to put down to to join in to grow up/out of 11. Write down 10 sentences of your own with phrasal verbs. Mind their meanings. Unit FOUR TEXT GRAVURE PRINTING Gravure printing (intaglio) is a very old printing process, whose beginnings (copperplate engraving) date back to the early fifteenth century. The distinctive feature of gravure printing technology is the fact that the image elements are engraved into the surface of the cylinder. The non-image areas are at a constant, original level. Prior to printing, the entire printing plate (non-printing and printing elements) is inked and flooded with ink. Ink is removed from the non image (by a wiper or blade) before printing, so that ink remains only in the cells. The ink is transferred from the cells to the printing substrate by a high printing pressure and the adhesive forces between printing substrate and ink. Today gravure printing accounts for a market share of 10–15% in industrialized nations. This percentage share has remained almost constant for two decades, with a slight downward tendency. Gravure printing is principally used for very long print runs. The minimum print run is approximately one million copies. Weekly magazines of general interest and mail order catalogs are therefore the main products produced by means of gravure printing. Another major area is in the printing of packaging, from extremely thin foils to thick cardboard. With gravure printing, straight printing and perfecting is done in systems where the first side of the web is printed in multicolor and then (in-line) on the opposite side. With the exception of sheet-fed gravure printing, which is now found only rarely, web-fed gravure printing requires a gapless gravure cylinder, onto which the image is applied directly, by means of etching or engraving. For this, the cylinder must be prepared in a costly mechanical and galvanic process. In its basic design, the gravure cylinder consists of a thick-walled steel tube with flanged steel journals. All of these joints are welded during the manufacture of the gravure cylinder so that a solid roller body is created which still has to be balanced so that there are no vibrations when running at high speed (typically up to 15 m/s) in the printing press. Etching For transferring the image onto the gravure cylinder, conventional etching processes use a pigment paper, which is coated with a gelatin layer and sensitized (i. e., made light sensitive) with a chrome saline solution just before use. First the crossline screen and then the imaging film are exposed onto the pigment paper in copying frame. The pigment paper is then “laminated” onto the gravure cylinder surface in a special pigment paper transfer machine. A stabilizing base paper, which is later removed, ensures that this transfer takes place in accurate register. The use of an “autofilm” where the photo emulsion is poured onto foil makes this base paper redundant. The process that follows, involving softening, base paper peeling, and washing out of the unexposed and therefore soluble gelatin in approximately 40 °C warm water (in this process the cylinder turns in a water bath) followed by a drying process, can be described as “developing.” All these operations are carried out in program-controlled automatic developing machines. Electromechanical Engraving The operations involved in electromechanical engraving are significantly shorter compared to the etching process. Nowadays, they are normally controlled directly with the data recorded in prepress. In this way the mounting of a scanning original on a separate scanning drum that runs synchronously with the engraving machine is also no longer needed. Hence, the engraving machine only consists of a lathe-like device, into which the prepared gravure cylinder is mounted. The gravure cylinder rotates during engraving at a constant surface speed depending on the screen at approximately 1 m/s. At the same time the diamond stylus of the engraving head moves at a high frequency( 4–8 kHz). The diamond penetrates the copper at different depths and produces the cell. Laser Engraving In the past there have been numerous attempts to make engraving faster and cheaper. One possibility lies in the implementation of non-contact methods, such as electron or laser beam. In individual cases, laser engraving is already in practical usage today. In the year 1995, a direct engraving process using a laser was brought onto the market (“Laserstar”by Max Dätwyler AG), where a solid-state laser engraves a zinc layer. The cell shapes produced are similar to those of etched cells (the process operates at 70 kHz engraving frequency). The engraved cylinder is chrome-plated after a grinding and cleaning process. Dressing of the gravure cylinder after printing is carried out using similar chemical, mechanical, and electroplating methods as with a copper cylinder. Basically the step of copper plating (to permit engraving copper) is replaced by a process of electroplating zinc. Laser engraving opens several new doors for gravure printing. The unwanted saw tooth effect with fine fonts can be reduced. Indirectlaser engraving processes use a light-sensitive black layer that is applied onto the copper of the gravure cylinder. The laser removes this layer in accordance with the image (on the basis of already available digital data files). The gravure cylinder is then etched. As in every conventional printing process, in gravure printing there is also an impression roller. This cylinder must be sufficiently stable and as small as possible in its diameter to assure a narrow printing nip for a better (i. e., sharper) print of the gravure cylinder. Therefore, previously (prior to 1960), it was common to arrange the gravure cylinder, a smaller intermediate roller (impression roller), and a larger cylinder above one another in a three-roller system. (If the small intermediate roller were brought into contact with the gravure cylinder without the pressure from the large cylinder, there would be too large a deflection of the impression cylinder. Hence, the contact pressure in the center of the two cylinders would no longer be sufficient in the printing nip. The impression roller coveringconsists of a special rubber layer of high shore hardness and is applied seamlessly. The impression roller is driven non-positively via the gravure cylinder when in contact with the printing material. In order to promote the transfer of inkfrom the etched gravure cylinder onto the paper wrapped around the impression roller, the impression roller or the web is electrostatically chargedjust beforehand. The ink meniscus (the top surface of a column of liquid) in the ink cells is thus raised and wets the paper more effectively. This device, which works with special voltage generators, is called ESA (Electro Static Assist). For this the impression roller must be supported by its bearings in an electrically insulated manner. In gravure printing the ink must be applied into engraved cells of the gravure cylinder surface. For this the ink must have a very low viscosity – it mainly consists of a solvent with a low boiling point (Toluene) and pigment- containing resins or resin-embedded pigments. To fill the indented elements, that is, the etched or engraved cells, only requires an ink pan that is filled with gravure printing ink, into which the rotating gravure cylinder is immersed. In order to prevent strong foam formation and splashing of the ink, a pan roller with a soft covering runs simultaneously in the ink pan. Due to friction, this roller runs more slowly than the gravure cylinder circumference. This allows the application of a homogenous ink film onto the gravure cylinder without splashing. Special splash guard plates on the gravure cylinder ends also prevent ink splashes at the cylinder edges and the superfluous ink falls into the ink trough beneath the height adjustable ink pan. From the ink trough, the ink flows into an ink tank positioned in front of the printing unit there it is mixed with fresh ink, cleaned by filters, its viscosity is checked and it is pumped back into the ink pan. Since the gravure cylinder also takes up ink on the non-printing areas when dipped into the ink pan, the superfluous ink must be removed from the gravure cylinder surface by means of a doctor blade. This blade is often referred to as the “soul” of gravure printing; its design is of immense importance. The blade itself simply consists of a thin, wear-resistant steel strip that is bent slightly and mounted in a blade holder. Previously, a distinction was made between a thicker support blade, located above and set slightly further back, and the blade itself. Today, it is usual to use blades with thicker but shorter profiles. The ink used for gravure printing has a low viscosity, so that the ink in the cells can run out properly and be transferred onto the paper. This low viscosity is principally achieved by using a high proportion of solventwith low boiling point in the ink. To dry the printed ink, the solvent must evaporate in a high velocity air dryer after leaving the printing nip. Рис. 2 Gravure printing enables high-quality and consistent reproduction of the finest photographic details in even the smallest of images on thin and flexible printing material and a large number of multiple-ups on one gravure cylinder. Furthermore, this process achieves the highest, most constant and continuously reproducible print quality. Moreover, printing on both sides of the web can be carried out easily in one pass, even with an alternating number of colors. Webs printed in gravure printing can be finished immediately and long runs can almost always be printed with one set of gravure cylinders. Many brand-name goods manufacturers employ gravure printing for the printing of their packaging for cigarettes, candy, soup packets, coffee, cakes, pastries, butter, and cheese. Even washing detergent boxes, plastic bags, and wrapping paper are often printed on gravure presses. |