Lithography suitability summary

Foreword

Printing suitability mainly depends on the various needs of printing and copying quality. It covers the processes and technologies of manuscripts, copying, printing, processing and binding, as well as various materials, equipment, environment and related conditions involved. Requirements, in order to obtain the best quality of all operations.

First, the relationship between printing and fitness

(1) Letterpress printing: There is a depression at the imprint and a feeling of frame border around the imprint. Suitable for small number of forms, business cards, envelopes, stationery, self-adhesive stickers or sets of text or simple illustrations.

(b) Lithographic printing: The embossing does not protrude or sink, and the prints are delicate and delicate. Suitable for multi-color prints in black and white and color books, color magazines, posters, advanced letter paper, paper boxes, calendars, newspapers, etc.

(3) Gravure Printing: There are two kinds: 1. Engraving intaglio—the impression of its intaglio will be slightly convex when touched by hand, and the ink is thick and strong, suitable for the printing of securities and banknotes. 2. Photogravure - its imprint appears to have a faint dot-like appearance, also like continuous tone. Suitable for large-volume color magazines, plastic films, aluminum foil and other packaging and printing materials.

(d) stencil printing: imprinting into burrs and thick ink layers. Suitable for a variety of printed objects, including the surface of hard and soft objects with flat surfaces and curved surfaces. Such as: plastic surface, large posters outside the trunk, printed circuit boards, local glazing, transfer paper, fabrics and so on.

(5) No-printing: The printing methods applied in electronic technology include the use of dry toner and liquid ink. The former has a slightly convex pattern and the latter is similar to a lithographic pattern. Suitable for small lot, medium and low quality color printing or color printing.

Second, the manuscript's suitability

(1) The manuscript, ideal conditions should include: 1. Write clearly, the content should not be modified after the manuscript. 2. Editing contains complete edits, chapters, sections, items, etc. 3. Punctuation marks and paragraphs are all intact and carefully arranged. 4. The typo and other characters have been checked and corrected.

(b) In the form draft, ideal conditions should include: 1. Clear lines and correct figures. 2. The decimal point should be properly aligned. 3. The colors of negative or special text and numbers should be clearly marked.

(3) Drawings such as charcoal paintings, Chinese paintings, oil paintings, or watercolor paintings. The ideal conditions should include: 1. Clearly structured and harmonious tones. 2. Normal color and good texture. 3. The theme is correct and the performance is natural. 4. If the original painting is too large, it must be translated into a positive or photograph. The color tone should be the same as the original painting.

(D) Positive or photo, the ideal conditions should include: 1. The exposure is correct and the concentration is good. 2. The image is sharp and beautiful. 3. The contrast is appropriate and the levels are rich. 4. Good composition and good resolution.

Third, the appropriateness of the replication technology

(1) Text reprint: Due to the differences in the types of manuscripts, the reflectances are not the same on the coated paper, the writing paper, or the writing brush written on burrs or other paper. Special attention must be paid to the revised exposure time when copying. Secondly, the visual results of the naked eye and the copying of the plate-making camera will also cause some differences. It will often take time and experience to do well.

(B) black and white scan over the net: As the density of the original document often can not match with the scanner, over the net must pay special attention, especially from the bright part to the dark part of the concentration and curve values ​​(or called gamma), or bright Both shades and dark-tone photographs are due to differences in the operator's technology and there are considerable differences in quality. Therefore, at the time of adjustment, it is advisable to pay attention to and compare the quality differences between manuscripts and reproductions, and it is not difficult to obtain ideal reproductions.

(3) Scanning Separation: The control of the color control and the gray balance, and the adjustment and adjustment of the optical department and the sub-optical department, all require some experience in order to do a good job. Sometimes the need to make local color corrections is a difficult operation. It takes many years and months before the operation can be handy.

(D) manual imposition: Before the imposition of the first to take into account the binding method, because of different binding methods, the number and order of imposition will also be different, while the binding, hardcover and paperback the same order, but its reserved The distance between the backs is different, and the binding must be determined before the make-up so as to match the arrangement and the imposition. In the collage requires a page of the entire collage, can not be cut in the film, so as not to streak in the print, this situation is not easy to find in the plate, wait until the machine when printing found, and then repair with chemical liquid Or rub off with a pumice pen, not only a waste of time, but also will damage the layout, and sometimes there will be other problems.

(5) Computer group pages: Although this type of equipment is the most recent, with the exception of a few large-scale factories, many small and medium-sized factories do not have the ability to purchase such expensive equipment. Although it is fast in operation, it cannot be modified after the film is output. Otherwise, the film must be re-launched, which will increase the production cost. Therefore, it is mostly used for making small editions in China, and it is not used to make large editions. Large editions still use hand-made imposition methods. Since this operation depends entirely on computer devices, the input, storage, editing, calculation, output, and auxiliary devices are different because of their different software functions, but the basic principles are similar.

Fourth, the suitability of printing technology

Lithography is very different from other formats. Other formats are mostly direct printing, that is, physical printing in which the printing plate is in direct contact with the paper or the printed body. The lithography is a chemical printing method using the principle of mutual exclusion of water and ink. Therefore, the applicability of other technologies is very different from other formats.

(1) Piles of paper: It should be noted that the cross-threads of the paper cannot be mixed and piled together. The entire pile must have a uniform thread flow. Otherwise, the color of the printed products will change due to the paper stretching, and the product quality will not be consistent.

(B) Ink balance: Since the lithographic printing machine must have a wet system to provide layout water. There are three types of systems: 1. Traditional water systems. 2. Semi-alcoholic system. 3. Continuous alcohol system. In order to make the distribution of water and ink on the printing plate average, it is necessary to make appropriate adjustments in order to obtain the best printing quality. When the ink is too much, it will cause layout pollution. Too little ink will make the line drawing not print or incomplete. Too much water will make the ink lighter, and vice versa, it will make the wireless part of the layout stained with ink. The alcohol system should pay attention to the composition and proportion of alcohol, and it also has a great influence on quality. Although these are very important tasks in lithographic printing, they can be handy if they actually work for a while.

(C) dusting: There are two kinds of dusting device: 1. Universal type. 2. Electrostatic type. Regardless of the type used, the main function is still to spray a layer of thin powder on the dry ink, so as to keep a little distance with the paper stacked on it, so as to avoid anti-printing. However, the quality of the powder and the amount of powder to be sprayed must be paid special attention. Poor quality or too much dusting will cause poor ink transfer, insufficient ink, and poor printing patterns during the next overprint or backside printing. Too little dusting will cause sticking of the upper and lower papers together, anti-printing and other phenomena.

(D) Indoor temperature, humidity and air flow: These are also major factors that affect the printing quality. Although it is not directly related to the technology, if the temperature, humidity and air flow are changed at the top and side of the printing press, it will make the layout. Water is not easy to control. In the past, because the cold air tuyere was on the upper left side of the printing press, the airflow on one side of the printing plate was larger than the other side. Therefore, on the large airflow side, the layout water was easier to dry and the ink-water balance operation was difficult to achieve. Printing technicians are very troubled and cannot get good print quality.

Fifth, the suitability of post-press processing

(A) Post-processing: After printing, the surface finishes are: Water-based PVA. This is an early method. It has good transparency, good resistance to moisture and water, but it must use solvent-resistant inks. It is rarely used nowadays. At present, there are more commonly used UV coating and PP, OPP plastic film, etc., the film has small flexibility, good stiffness, do not have to use high heat and high pressure, single-sided and double-sided blemishes can be, do not have to pay too much attention to the ink drying The problem is therefore the most popular method at this stage. It is divided into smooth and matte, each with its own different feelings and effects. Generally speaking, advanced book covers, book clothing, and Chinese paintings are often used for matte reproduction. For glossy books and magazines that highlight color effects, bright surfaces are often used. Only when the humidity changes, thin paper can cause curling as its disadvantage. Another bronzing process must be carefully considered before or after polishing. After the first bronzing, the glazing has a protective effect, so that the gold foil is not easily worn, but the gloss is poor. If the bronzing after the first glazing is sometimes difficult after UV glazing, this must be considered in advance.

(2) Stapling: Although there are various kinds of binding, those commonly used in binding include hardcover, paperback, saddle-wear, threading, and binding. Various types of binding have different characteristics. In the binding process, it is necessary to pay attention in advance to meet the requirements of processing machinery. , to do all the preparations, can only be carried out smoothly, otherwise it will produce a lot of unnecessary post-order issues, such as: folding alignment, folding sequence, binding time extension, homework and so on. Another hardcover, pay attention to paper and paste materials, and whether it will be after the paste due to poor absorption of the material off, but also pay attention to whether it will be affected by changes in weather and its quality after the paste to be fully dry and other factors. Binding books must pay attention to the quality of the hot melt glue, otherwise, the inner pages and the cover will fall off due to brittleness.

Sixth, the suitability of finished products

(a) posters: mostly single prints. The requirements for the use of paper should be not easy to stretch, and the ink used should not fade easily. Because it is often hung in the hall and exposed to the sun, it is best to protect it with a layer of PP or OPP film after the printing is completed. This will not only enhance the color brightness, but also make it difficult to surface. Damage, but also to prevent ultraviolet radiation, reduce the chance of fading.

(B) Catalogue: Its main function in the performance of product features and advantages, so the production of beautiful and attractive is the most important condition. This kind of print must use high-quality paper, beautiful color pictures, exquisite design, careful processing and binding, so that readers like it at first glance and achieve the desired effect.

(III) Magazine: It is a book that is distributed to the general public. Sometimes there are certain objects. The paper used is mostly coated paper. The printing method is mostly lithographic. The binding methods are mostly saddle stitches. Thick books are used in other ways. Production also has time and quality requirements.

(D) books: divided into stringed paperback and hardcover books, threading paperbacks for schools, general novels and other books. Hardcover focuses on advanced books and dictionaries. In the production, in order to adapt to its long-term preservation characteristics, it must be long straight for the direction of the trade flow to be more straight.

(five) form: often multi-joint type, the current use of non-carbon paper is more, you can use carbon paper as its main advantage, but non-carbon paper has the upper paper, medium paper, the next paper, the upper paper for upper use Middle paper for the middle and lower paper for the lower. When using, please pay attention to the layer of the paper. When the following paper is placed on the upper layer, there is no replication function.

VII. Suitability of materials

(1) Selection of printing plates: There are many kinds of printing plates, which can be: 1. Plates are divided into aluminum, zinc, stone, resin, nylon, cardboard and glass. 2. The structure is divided into single layer, double layer and multiple layers. 3. The plate making method is divided into manual, transfer, optics, and electronics. 4. Plates are divided into plano-convex, plane, and plano-concave. 5. Grinding methods are divided into ball mill, brush mill, chemical mill, electronic chemical mill, blasting mill. 6. Layout treatment consists of chemical and anode. 7. Film coating methods are self-coated, machine-coated and pre-coated. 8. The film coating surface is divided into single-sided and double-sided. 9. Shaiban tablets are divided into positive and negative types. 10. Film processing methods are divided into film type and film type. 11. There are 11 types of printers, including proofers, express machines, pagers, rotary machines, and business printers. Seen from the above, there are quite a few types. In fact, at present, many printing plates used by Taiwan's lithographic printing plants are pre-coated and positive ones, and are generally referred to as the PS version. The quality of printing using this type of printing plate is quite high, and the plate making procedure is simple, as long as it is automatically processed in the plate processor, it can be completed in a few minutes. However, there are still a few home-style printing plants that use zinc or aluminum plates to make plates that are specially designed for small amounts of book printing.

(b) the choice of paper: there are three types of choices, quality and weight. In terms of species, there are 1. Printing Paper: Bond Paper, Book Paper, Magazine Paper, Newsprint Paper, Mould Paper, Coated Paper, Bible Paper, Dowling Paper, etc. 2.