Quality Control of Book Publishing and Printing Process

In the process of book publishing and printing, quality control is a very important link. Readers are inseparable from the selection and use of books and the quality control of the content, design, editing, and printing process of books. Quality management during the printing process is an important part of book publishing.

The quality of the book includes the quality of the content of the book, the quality of the design and the quality of the printing. With the improvement of people's living standards, readers have not only paid attention to the quality of the content when buying books, but also the book design and print quality have become an important standard for measuring the quality of books. The high-quality design and printing level can attract people's attention and enhance their trust in the content of the book, which is finally loved and purchased by readers.

The quality of Book Printing is also an indispensable factor in evaluating the quality of books. Content and form (appearance) are two major elements of a book. The printing of books belongs to the appearance production of books. A good appearance can better express the content and promote the expression of the content; on the contrary, a bad appearance can not only not express the content well, but also have a negative impact on the content.

1 Quality control in publishing

The quality control of the publishing process mainly includes the design and production of graphics. In the pre-press production process, the input, editing, output of graphics, post-printing process design, and binding design are all important factors that affect the quality of the book.

1) Scanning input of pictures

The scanning and processing quality of the image is an important prerequisite for ensuring the final color and tone reproduction of the image. The image is processed accurately and with high quality, and the image information such as tone, gradation, contrast and saturation on the original is kept as much as possible. The basic standard of image quality.

There are usually many illustrations in current books. During the examination of the illustrations provided by the author (including color pictures, black and white image pictures, line drawing pictures, etc.), the quality of illustrations should be paid attention to: the color picture and black and white picture artwork must be clear and level It has a strong sense, in which the color image should be bright, and the lines of the line drawing image should be clear and full. When scanning and calibrating pictures, it is necessary to distinguish the characteristics of different types of originals such as photos, printed materials, hand-painted rounds, positive films, negative films, etc., and accurately calibrate. When scanning originals with rich levels, high saturation, and strong contrast, you should restore the originals as accurately as possible. If the original quality is not very good, there is a color cast or low saturation, you should adjust accordingly to make the scan The resulting image is brighter and more authentic than the original.

The scanning resolution should meet the publishing requirements. The scanning resolution of the printed image is generally set to 1.5 to 2 times the number of dots and lines. Generally, the scanning resolution of color books is 300dpi, and the number of dots and lines is 150lpi. The scanning resolution of fine pictures It is 350dpi, and the number of printed dots is generally 175 ~ 200lpi. During the scanning, it is necessary to reasonably select the corresponding color separation parameters for the different printing paper and printing equipment, determine the black and white field calibration parameters, and adjust the image tone appropriately.

2) Processing of pictures

At present, the popularization of digital cameras makes digital pictures such as digital cameras more and more used, which also puts forward higher requirements for image processing. Not only must it conform to the characteristics of the printing process, but also consider the targeted processing of digital pictures .

When processing pictures, it is necessary to adjust the parts of the original color and tone that are not good. Usually, professional software such as Photoshop software from Adobe Corporation of the United States is used to perform morphological transformation, color transformation, gradation correction, image modification, and special effect design. Waiting for the processing method to make it accurate in color and balanced in tone. At the same time, for many line drawings, it is generally necessary to use the corresponding graphics processing software (such as Freehand, CorelDRAW, etc.) to redraw. The printing stage will inevitably affect the printing quality. There are few levels for downloading photos on the Internet, excessive sharpening, inaccurate colors, and low pixel count. After printing and copying, the effect is not good, and should be used sparingly and with caution.

On the other hand, when processing pictures, we must consider the requirements of the printing process, adjust the tone of the picture through the software, elongate the middle tone, and concentrate the main layers in the 10% ~ 60% visually sensitive area to ensure highlights and darkness Adjust the gradation quality of the part and compress the gradation to within the effective range of printing, so that the tone of the original corresponds to the tone that can be reproduced by the printing to the maximum, so that the image is clear and true.

The types and levels of manuscripts are different, and the content and colors are very different. Copying photos with a consistent style and meeting printing requirements is the central task of scanning and processing. The basic principle of this work is: be faithful to the original, higher than the original and strive for a unified style. [next]

3) Matching of book design and printing process

Publishers should work with printing companies to choose a reasonable printing process to achieve the best book printing results.

① Format and selection of printed sheets

Sometimes in order to highlight the diversity and novelty of the book, the publisher will choose some special-shaped format, but in the printing process of the printing company, because the size of the special-shaped format is inconsistent with the normal paper format, it will increase the difficulty of printing production and prolong the cycle. As a result of increased costs, it is best to choose a normal format and a vertical format when choosing a format. When determining the printed sheets, it is better not to have zero printed sheets such as 0.125 printed sheets, 0.875 printed sheets, etc., because the zero printed sheets will also lead to an increase in the printing process, a longer period, and increased production costs.

②The use of special crafts

Lithography is generally used for book printing, and there are no special requirements in the process of inner text printing. For the cover making, publishers often use some special processes, such as laminating (light film, dumb film), bronzing, UV glazing , Imprinting, special printing, etc. When using these special processes in the binding design, you must consider the different conditions of the paper or material being printed. Some materials have a bad bronzing effect, are not easy to burn up, and are easy to be confused. Not only is the loss increased, but also the printing cost is increased. However, the desired effect is not achieved, and the cycle is extended.

③ spine

There are many ways to determine the width of the spine. A better method is to use the same internal paper and match a certain number of copies to determine the thickness of the spine. However, considering the book thickness when reprinting, there will be Changes, the same paper will be different in different batches, there should be a certain margin when designing the spine, and the spine should not use color strips or ribbons different from the cover one and cover four colors as much as possible, on the cover, cover four and the spine Do n’t design wireframes, and the spine words should not be too large or too full compared to the back of the book. This design not only facilitates the production of the printing plant, but also easily improves the quality of the product and reduces the occurrence of quality problems.

④Layout design

In order to pursue the effect, some designers will design some small characters (below the fifth size), especially the fine-text Song type characters or some thin lines into four-color characters or reverse white characters. This design will greatly increase the difficulty of the printing and binding process. If you use offset paper to print, it is easy to produce quality problems such as inaccurate overprinting, paste characters, and white leaks.

When copying neutral gray, the color is not easy to grasp, and it is often easy to cause color cast. This is particularly prominent for reprinted books. Therefore, in the pre-press production process, it is recommended that some grays formed by superimposing four colors be made into special The color is better, and the color gamut of the spot color is wider than that of the four-color printing, which can realize the colors that CMYK four-color printing ink can not show.

⑤ Design of binding process

Wireless perfect binding is currently a commonly used binding process, but books with particularly thin or thick spine are not suitable for wireless perfect binding. Because the tensile strength of the hot-melt adhesive used in the binding is not guaranteed, the degree of anti-aging is poor, and the durability is poor. For books that need to be stored for a long time, the middle of the book block cannot be opened, it is inconvenient to read, and it may also cause the intermediate opening. The quality of the page is dropped, so it is not suitable for the method of wireless binding, but the process of locking the line and then encapsulating it must be used. Books with a particularly thin spine (generally less than 3mm) are also not suitable for the processing parameters of the binding equipment, because the spine is too thin, which is likely to cause the quality problems of the back of the spine and the skew of the spine.

Although the binding process is the last process, in the early stage of the layout design, you should consider the position of the plate core during imposition and the position of the binding and milling hole in advance. For slightly thick saddle-stitched books, the inner page is easy to produce a plate core The "outward movement" phenomenon, in order to correct the "outward movement" of the internal pages, the amount of internal movement of the core page must be adjusted. At this time, the position of the core of the core should be considered to be indented with the external post to the internal post to ensure the entire book. The visual experience is consistent.

For cross-page graphic design, the requirements for different binding methods are also different and should be treated separately. Binding products should not only consider the 2 ~ 3mm milling volume, but also consider the 5 ~ 8mm encapsulation side glue position for the cover and book block adhesion. Otherwise, the spread image may appear broken, misaligned, missing text, and the content is milled off. If a book with a cover on the cover is not designed, the cover has a large capacity to produce edge curling, the inner core is easy to be dirty, and the appearance is not beautiful. [next]

2 Quality control of printing

The elements of printing quality control are: dots, the true degree of color reproduction, and the stability of the printing process. The mesh value (dot size) of the overprint area is the most important control element. Of course, there are other factors that affect the printing quality of the shadow, such as ring-shaped white spots, paste, dirty, overprinting and so on. For customers, the reason for their dissatisfaction is that there is a color difference between the original and the printed pattern.

1) Film quality control

The density value of the black field on the film should reach 3.5, which is lower than this value. During printing, the dots will transmit light, causing the photosensitive layer to be exposed, causing the dots on the printing plate to be not solid. Dropped, causing a net drop.

Strict inspection of the film quality before printing can find the problem at the first time and remove the major hidden dangers of later printing. Otherwise, the problem will not be discovered until the printing process or after the printing is completed, which will bring great loss.

2) Printing control

When printing, it is necessary to strictly control the exposure according to the requirements. If the exposure time is too long, it will cause the printing plate to be unsolid or even lost, and the printing will be dropped. When printing, it is necessary to ensure that 3% of the small dots are not lost and 95% of the dots are not blurred, so as to ensure the perfect reproduction of the layers and gradations in the printing process.

The operator should determine the different exposures under different conditions with the test strip according to the situation. The environment for printing should be standardized and neat, and the original and printing glass should be cleaned before printing to avoid uneven air extraction caused by small foreign objects and false graphics. Secondly, the control of the development process is also an important factor in the quality of the printing. The developer concentration must be strictly prepared according to the requirements and the development speed should be controlled to avoid the loss of small dots due to high developer concentration, high temperature or fast speed, or dirty plates due to low developer concentration, slow speed or low temperature. Blurred phenomenon.

3) Dot size control

The dot size is a decisive factor in determining the printing quality. The process of plate making and offset printing will change the dots, so the dot expansion, sharpening, deformation and ghosting of each process must be strictly controlled. We can use the printing control bar and magnifying glass to monitor the changes of the dots. During the offset printing process, dot expansion will occur, which requires continuous monitoring of product quality during the printing process, discovering problems, and adjusting equipment in time. [next]

4) Color difference control

Color difference refers to the size of the color difference between the printed product and the original. Only when it is controlled within a certain tolerance range, the printed product is qualified. Use a spectrophotometer to measure the CIELAB value and color difference value of the printed matter and the original, and then draw the obtained color difference value and color difference allowable range on the coordinate chart to obtain the color difference allowable map, which can be used to estimate the degree of product qualification . Normally, the eligibility of printed products is judged based on human visual experience and customer satisfaction or rejection of printed products.

5) Ink layer thickness

The thickness of the ink layer of the printed matter has a great influence on the quality of the printed matter. The thickness of the ink layer of the printed product is related to the viscosity and fluidity of the ink. The viscosity of the ink is too large, the ink layer is thick, and the paper wool phenomenon will occur when printing; on the contrary, the ink layer is thin, and the ink roller is easy to slip when the ink roller rotates, causing ink sticks, which will increase the dots, distort the image, and print the surface gloss. Degree difference. In general, the ink layer is printed as thick as possible under the premise that the back side is not smudged. When the printing machine is faster, the ink layer can be properly thickened to achieve the desired ink color. In addition, when the printed paper surface is rough 3. When the ink absorption is strong, the ink layer should also be properly thickened, so that the layout is not easy to bloom.

6) Stability of printing process

In order to maintain the stability of the printing process, it is necessary to regularly check the printing equipment. As the season changes, the machine keeps running for a long time, and the pressure between the printing cylinders, the pressure between the ink rollers and the water rollers will change slightly, and these changes will affect the printing quality to Important. The machine and maintenance personnel must check the rubber roller pressure and roller pressure every half a month, and adjust and solve the problems at any time if they are found.

Strengthen the inspection of graphics and text, especially in the pre-press process, the film should be inspected, problems and quality hidden dangers are found in time, and unnecessary waste is eliminated. Inspection in printing is even more indispensable. It is one of the effective means to control quality. The focus of inspection during printing should be on the control of the printing quality, such as checking whether the opening samples, layout samples, and plate-changing samples are the same as the original ones, checking the page number sequence and the quality of the graphics, and checking whether there are missing characters, etc., so as to be effective Control printing quality to prevent various quality accidents.

7) Paper selection and control

The surface strength of the paper is too low, it is easy to cause the surface of the paper to be rough and de-powdered due to the adhesion and pulling force of the ink during the printing process, and the printing quality is poor. Only use paper with higher surface strength to obtain better printing quality. In order to ensure good printing quality, paper with higher surface strength is used, or the printing pressure is appropriately reduced, or the viscosity of the ink is appropriately adjusted. Therefore, it is necessary to put forward specific requirements in the paper-related standards. For example, in the national standard GB / T18359-2001, the surface strength of coated white paperboards such as A, B, and C is prescribed to be 2.8m / s or more, 1.6 m / s or more and 1.0m / s or more, as a basis for use, the paper should be correctly selected according to different styles and grades to ensure printing quality.

When the moisture content of the paper is too high, the paper becomes soft, swells, the tensile strength is reduced, and the plasticity is enhanced, causing the print to not dry in time during the printing process; or the moisture content is too low, the paper is brittle and shrink, easy to break and break, and easy to produce Static electricity affects the normal progress of printing. The expansion and contraction of the paper makes the overprinting inaccurate. In addition to the influence of environmental temperature and humidity, the moisture content of the paper is also related to the nature of the paper and the materials used. Generally, under the same temperature and humidity conditions, the greater the paper tightness, the larger the sizing amount, and the more long fibers in the slurry, the lower the water content. During the storage and printing of paper, controlling the proper moisture content is the key. For example, in order to control the moisture content of the paper to 4-8%, the ambient temperature should be controlled at 18-24 ° C, and the relative humidity at 40-55% RH.

White material cutting is often an important link that is easily overlooked in quality control. The size and quality of the cut directly affect the printing rules and quality. Improper operation during cutting will cause incorrect size. [next]

3 Binding quality control

Binding is the last production process of books into books, mainly including folding, page matching, thread binding, wrapping, finishing and other processes. The binding process is extremely complex, and its complexity is unmatched by any one process. There are more than a dozen binding process flows, and most of them have no commonality. It is understood that many binding quality problems occur when the binding has been completed or the book has been sent to the customer. Therefore, preventive work should be done in the binding production process to prevent accidents. Once quality problems occur, they should be dealt with and resolved in time to avoid inadvertently causing waste.

1) Influence of binding materials

There are hundreds of types and styles of binding materials, and each kind of material involves a lot of knowledge. For example, there are more than 10 kinds of cover materials with different textures. These different materials involve the use of bonding materials. Different is related to the object of bonding and the firm effect of bonding. The correct use of materials directly affects the firmness and shelf life of books. At present, quality problems such as page-off, uneven book back, broken book blocks, air bubbles, eyelets, and glue spillage in wireless glue binding are directly related to the materials using EVA hot-melt glue.

The crease of the cover paper material is not suitable for breaking. Now the thickness of the cover is getting bigger and bigger. The cardboard or paper above 200g / m2 is designed with a kerf process. When the creasing is indented, the crease breaks and leaks, which destroys the appearance quality of the book. In fact, if the cover of 200g / m2 or more is folded, the book binding process will be very difficult, and the quality cannot be guaranteed.

The thickness of the cover paper and the book block are quite different. In order to improve the binding effect of books, there are many books with different cover thickness and paper thickness or weight? Snow is very different, resulting in unequal tension, when the cover is lifted after wireless binding, the first page of the book block is pulled to reveal the glue Bottom, causing non-conforming products. This kind of product can solve the problem of glue leakage if a gram or a liner with a moderate weight is added between the cover and the first page of the book block, but many publishers are reluctant to make this plan in order to reduce costs. Does not consider the processing effect.

2) Wireless binding and milling back quality control

The wireless binding does not use wire or wire, but uses adhesive to bind the book block. Its technological process is roughly: collating, copying, collating, milling back, slotting, upper adhesive, upper adhesive, bag cover, Forming, drying, slitting, cutting finished products, stacking light books, inspecting finished products, bundling.

In wireless perfect binding, milling back and slotting are the key processes. The back milling depends on the thickness of the paper and the number of folding times. Generally, 2.5mm ~ 3mm is milled, and the depth of the slot is required to be 1.0mm ~ 1.5mm. If the depth of the milling back and the slot is not enough, it will inevitably affect the penetration of the glue, thereby causing quality defects such as loose pages and loose pages. If the stickers are not fully aligned, bundled unevenly, or turned into the milling back during the finishing process before binding, it will also cause the pages of the book to not be milled, resulting in poor glue penetration, falling pages, loose pages, and insufficient firmness. Such quality defects. [next]

3) The influence of hot melt adhesive on the quality of books

The parts for glue binding are on the back and sides of the book. The hot-melt adhesives used for the glue and the side glue are also different. The performance of the two is also different. The use temperature is also different. Only by grasping the appropriate process parameters can we ensure the quality of the glue binding. . Glue temperature is particularly important for the quality of glue binding. The high temperature of the glue will make the glue too thin and insufficient in viscosity. The low temperature of the glue will make the glue too thick to penetrate and flow, and some will be small. The granular block is attached to the ridge surface or the side surface to make the cover wrinkle and empty ridge. According to different models, the general adhesive temperature is controlled between 160 ~ 180 ° C, and the side adhesive temperature is controlled between 145 ~ 165 ° C. Under normal circumstances, after gluing, spine glue can penetrate and fill the milling trench Preferably, the thickness of the adhesive after drying is between 0.8 ~ 1.3mm.

The post-press binding process is not only a complex processing process, but also an art processing process. Today's books are not only reading materials, but also a gift, artwork, and valuable preservation; it not only adds knowledge to humans, but also brings Give people artistic enjoyment. In the past few decades, the publishing industry has engaged in design, especially American editing. Snow personnel often contact with the technicians and teachers of the bookbinding processing factory to absorb the opinions of the bookbinding workers to improve and enhance the binding design scheme. , In the selection of materials, dimensions and other aspects, many problems have been avoided, and the consistency of design expectations and product completion has been achieved, and many high-quality products have been made. Therefore, there should be more communication between the publishing house and the printing factory, especially with the binding process. Everyone learns from each other, and designers can learn more about various binding processes in order to design more excellent works.

To sum up, under the conditions of market economy, both publishing houses and printing houses are responsible for improving the quality of book printing. Publishing and printing should become a collaborative department for quality management of book printing. In addition to the pre-press production, it is necessary to strictly manage the books printed by the printing enterprises, and the printing enterprises should also control the quality of the books throughout the printing process. Publishers and printers should communicate in a problem-solving manner, each should be responsible for their work, and work closely together to work together to improve the quality of book printing and provide readers with excellent and unified books and content.