Analysis on the current situation of post press pr

  • Detail

Analysis of the current situation of post press processing of digital printing

a few years ago, people thought that digital printing was a new thing, which was still a long way from commercial production. The reality at that time was also true, because there was a big gap between the quality of digital printing and people's requirements at that time, and the production efficiency was also very low, which was difficult to meet people's requirements

however, the speed of change and development of digital printing has completely exceeded people's imagination. Today's digital printing quality has become closer and closer to offset printing, production efficiency has been greatly improved, and the range of printing materials has become wider and wider. The excellent quality and printing effect of some printing products are even surprising. Digital printing has become one of the most attractive printing methods

however, from the perspective of binding and post press processing, there are still great differences between the post press processing of digital printing and that of offset printing. This paper attempts to explore the differences of post press processing of different printing methods, in order to provide some references for digital printing practitioners

pigment of digital printing and offset printing ink

one of the biggest differences between digital printing products and offset printing products is the colorant printed on paper. The pigment used in digital printing and the ink used in offset printing have completely different chemical mechanisms after long-term development. The pigment of digital printing is dry when it is printed on the paper, and then it is bonded to the surface of the paper by heating and melting the silicone oil. The offset printing ink is liquid, which realizes the drying of the ink and the adhesion of the ink film to the paper through the balance between the solid pigment and the liquid binder in the ink

the drying process of digital printing pigment on paper is also different from that of offset printing ink on paper. When the offset printing ink is dry, the liquid binder penetrates into the paper surface, and the solid pigment and some dry binder remain on the paper surface; The digital printing pigment has no liquid components penetrating into the paper. This difference reminds us that we must pay great attention to the post press processing of digital printing, because it may affect the quality of post press processing of some printing. For example, when the film covering processing method often used in offset printing is applied to digital printing, the color material on the surface may cause the film to not be well compounded. In addition, due to the role of silicone oil, it will also lead to some difficulties in post press processing. Many post press processors have found that if there is a large amount of silicone oil on the paper, it will lead to difficulties in post press polishing and coating

consider Postpress processing from prepress design

the prepress design of excellent digital printing will contribute to the successful completion of digital printing Postpress processing. In digital printing, the quality of prepress design has a great impact on the cost of post press processing. Because the paper specifications used in digital printing are limited, and a large number of digital prints are printed on one side, in addition to the prepress design of digital printing to strive to make the most effective use of paper, the following factors should also be considered

1. Paper thread direction

as long as the allowable condition is 0.12 ~ 0.14, try to make the thread direction of the paper consistent with the spine direction of the finished book. Due to the particularity of the combination of the color material on the surface of digital printing paper and paper, when folding, the image fracture is more likely to occur at the folding position in the horizontal filament direction. Therefore, when designing the post press processing technology of digital printing, we must pay due attention to the pre press design

2. Image position on the print sheet

usually, a large number of digital prints are designed so that the image is in the middle of the print sheet, but it is found that this wastes a lot of money and time when it is sent to post press processing after printing. For example, a size of 6 inches × The 9-inch image is designed to be 8.5 inches in one page × In the middle of the 11 inch printing sheet, the four sides of the printing sheet need to be cut when cutting; However, if the image is placed on a corner of the printing sheet (such as the upper left corner), only two sides need to be cut, so as to save post press processing time and reduce printing costs. However, if the other two sides of the image are bleeding designs, you still need to cut all four sides

consideration of binding and post press processing

carefully design the printing process from the beginning, so as to ensure the harmony between printing and post press processing. The following points should be paid attention to in production

1. Folding

because the color material on the digital print only stays on the surface of the paper, folding is more likely to occur during folding processing. Therefore, it is best to press the crease before folding processing, especially when the heavy color is printed on the surface of the print or the weight of the printed paper exceeds 80 pounds

2. Lamination

lamination processing on the surface of digital prints, especially after printing a large area of the field, will help protect the prints in post press processing, especially when cutting or packaging. Because in the process of post press processing, we must protect the printing sheets very carefully, otherwise, no matter how good the printing is, the waste will be increased due to the failure of post press processing. It may not be beneficial for double-sided printing to be coated on one side, because the uncoated side may peel off the printing pigment due to the effect of friction in the subsequent processing

3. Nicolas Wegener, chief operating officer of Raymond composites, said: "The technology of Deakin University can oxidize carbon fiber more quickly> horse riding binding is a good choice for most digital printing materials. It is especially suitable for the binding of thinner printing materials such as guides, pamphlets and brochures. One of the keys to making binding economical and practical is that it can be processed online with other processing methods, and the post press processing of page matching, folding, binding and online cutting at the same time can be required for digital printing To provide guarantee for fast delivery

4. Flat binding

when designing flat binding prints, pay attention to leaving enough binding space between the spine and the text. For example, when the line hole ratio of O-type spiral binding is 3:1 (refers to 3 holes per inch), at least 3/8 inch space should be left; When the line hole ratio is 2:1, at least 1/2 inch of blank space should be left. This blank is the distance between the edge of the line hole closest to the spine and the edge of the spine

in order to clarify the specific location of flat binding processing, designers had better understand the sample changes after digital printing with actual printing paper from post press processors before digital printing processing, which is particularly important for digital printing. A large number of computer design programs do not take into account the small changes in the thickness of the paper after printing, and the color material printed on the surface of the paper in digital printing will cause the changes in the thickness of the printed sheet. When Binding dozens of pages of digital printing paper, the accumulated thickness changes may make the binding size carefully calculated by the computer useless. Only by mastering the sample sheet change parameters of the actual production paper after digital printing can we accurately measure the book thickness in the printing design and ensure that the appropriate binding size can be obtained after post printing processing

5. Wireless binding

like the wireless binding processing of offset printing, the cutting blank of binding should also be considered in the wireless binding of digital printing. In addition to leaving 1/8 inch milling allowance at the spine of the book, 1/8 inch cutting blank should also be left on the other three sides of the book. In addition, a 1/4 inch gluing area should be left at the lower part of the book cover to prevent glue from seeping into the next book during binding. Wireless binding processing also requires that the printing of the cover should be a little larger than the bleeding printing of the text

6. Wireless binding hardcover

believe it or not, wireless binding hardcover processing is also an important post press processing method in digital printing and binding. The key of hardcover technology is how to firmly bond the book block and hard case to produce books that can be preserved for a long time. Although the cost and time of wireless binding hardcover seem to be somewhat incompatible with the digital printing facing the short edition printing market, some post press binding enterprises have prefabricated hardcover cases of different colors, styles and sizes required by digital printing hardcover for digital printers to choose at any time. Therefore, wireless binding hardcover has also become a common binding method for digital printing

integrated post press processing solution

the quality and speed of digital printing make it more attractive and become one of the increasingly widely used printing methods. Most digital printing products almost need some form of binding or post press processing to become practical printing products. It should be clear that most post press plus e-mail: conference@ processes can be applied to the post press processing of digital printing, but not all printers or post press processors can control the post press processing of digital printing. If the enterprise has rich knowledge of digital printing, understands the particularity of digital printing, has a variety of post press processing equipment, has strong production and processing capacity and rich post press processing experience, then post press processing of digital printing is no longer a difficult job

source: digital printing

Copyright © 2011 JIN SHI