Printers must read, how to avoid the 4 common problems of book printing?
In recent years, the implementation of the strategy of strengthening the country with quality has made publishing units and printing enterprises more and more aware of quality, and more and more attention has been paid to the quality of book printing. In addition to the annual "3.15" printing and reproduction quality inspection activities, some publishing units choose to evaluate the printing quality of their books by sending them for inspection. In the daily test samples of the book quality evaluation and appraisal working group of the Beijing Printing Association, most of the samples can meet the requirements of the testing standards, but a small number of samples have quality problems in printing, binding, surface finishing and other aspects of printing, binding, and surface finishing processes. This paper aims to analyze several frequently occurring book printing quality problems and propose corresponding improvement methods.
Valid graphics and text are cropped
In order to enhance the interactivity and reading experience of books, some books will design graphics and texts outside the center of the page, such as QR codes, book eyebrow text, etc. However, if these graphics and text are cropped incorrectly, it will lead to information loss or imbalance in layout, affecting the overall effect of the book. When the graphic design is too close to the incision (Fig. 1), the cropping positioning is inaccurate, and the folding error is too large (Fig. 2), it may lead to the effective graphic and text being cropped.
The upper part above the header text in Figure 1 is cut off
Figure 2 Page numbers cut off
To avoid cutting off important images and text, it is necessary to fully consider the position and size of images and text during the design stage, ensuring that QR codes, header text, page numbers, and other elements are not too close to the cutting edges and leaving sufficient margins to ensure that the content is fully presented. CY/T 200-2019 "General Design Specifications for Book and Periodical Printing" explicitly requires that "page numbers should not be placed on the binding side, and the distance from text near the cut edge should not be less than 3mm" and "the bleed size should not be less than 3mm." Secondly, printing companies should regularly calibrate positioning devices and strictly control the accuracy and quality of cutting. Finally, properly adjust the folding devices and implement folding processing requirements to ensure that folding errors are within a reasonable range.
Wrinkles
Wrinkle issues mostly appear on the spine of perfect-bound books, at the glued sections of the first and last pages, and across the entire book block. Uneven spine wrinkles are mainly caused by improper adjustment of the lower support when adhering the cover and inner pages, excessive pressure during cutting, or high moisture content in the spine glue; wrinkles at the first and last glued pages occur because the air between these pages and the rest cannot be fully expelled, and the pressure of the book board when attaching the cover to the inner pages causes wrinkling; uneven wrinkles across the book block are usually due to the fiber direction of the paper being inconsistent with the printing direction, or large differences in temperature and humidity before and after binding, causing the paper to absorb water and swell (Figure 3).
Figure 3 Overall Wrinkling of the Booklet
Controlling wrinkling issues requires printing companies to select adhesives that match the type and weight of the paper; correctly identify the paper grain direction during production; properly adjust the stacker height and the cutting press pressure; and, before binding, bundle and press the folded booklets to remove air between the pages, placing them in an environment with suitable temperature and humidity, thereby preventing such problems.
Foiling Smudges and Missed Foil Areas
Foiling not only enhances the grade and texture of a book but also increases its artistic and aesthetic appeal. However, the finished product often differs from the design, resulting in issues such as smudges and missed foil areas, which affect the overall quality of the book. These problems are closely related to the foiling temperature, pressure, materials used, and the compatibility of the foiling process. For example, if the foil plate temperature is too high or the pressure is too strong, the text and images may become blurred; if the temperature is too low or the pressure too weak, ghosting, missed foil areas, or peeling of foil powder may occur; if the foiled area is large with insufficient pressure, or if there are too many foiled spots but the foil plate material is too soft, the edges of the patterns may not foil properly, leaving margins at the corners. For instance, a hardcover book using linen fabric as the cover with small, thin-stroke foiling design can result in unclear or incomplete foiled text on the cover, affecting readability (Figure 4).
The publishing unit should evaluate the matching degree of materials and processes during design to determine the appropriate scheme. Printing enterprises should correctly adjust the temperature of the hot stamping plate according to the hot stamping material and the material to be ironed, and select the appropriate hot stamping pressure to achieve the best binding effect.
The size of the hardcover book floating mouth exceeds the standard
The floating mouth refers to the part of the hardcover case that extends beyond the cut in the book core, usually used to protect the book core. Ideally, the size of the three-sided float should be consistent to ensure a neat and beautiful appearance of the book. The size of the floating mouth of hardcover books exceeds the standard, most of which is manifested as inconsistent size of the floating mouth, which involves many aspects such as process control, material selection, and equipment accuracy in the process of book production. Inaccurate matching of book shell material specifications and book core format size, cutting size error exceeding the standard, and shell assembly process not meeting the standard requirements may all be the causes of the floating mouth size exceeding the standard.
When cutting the book shell, it must be carried out according to the size of the book core, the actual thickness and shape of the book core, and the cutting size error must be strictly controlled. During the assembly of the book case, a regular plate frame should be used to ensure the consistency of the size of the float.
The above types of problems account for an increasing proportion of daily quality problems for inspection, which seriously affects the use, beauty and interactivity of books, and needs to attract the attention of publishing units and printing enterprises. All publishing units should establish and improve the quality management system of publication printing, and comprehensively improve the printing quality of publications through book printing supplier evaluation, daily monitoring of printing quality, regular sample testing, in-depth study of national and industry standards, and participation in the formulation of forward-looking enterprise standards or group standards. On the premise of ensuring that the product quality of a single volume meets the requirements of the standard, the quality of the product batch is stable and consistent, hidden dangers are eliminated, and the quality risk is minimized. In addition, publishing units should establish quality feedback channels, collect feedback from readers and the market in a timely manner, and make targeted improvements to enhance the overall quality and market competitiveness of books.