Some issues to be aware of when printing, stapling and cutting digital printing

With the popularization and application of digitization, intelligence and networking in the printing field, the printing technology has gradually developed from analog to digital, thus opening the curtain of digital printing. Today, the rapid development of digital printing not only integrates into all areas of printing, but also continuously expands its market share. According to statistics, at present, the digital printing business in the United States has accounted for more than half of the total printing capacity, and this trend is still evolving. According to the British Paper Printing and Packaging Technology Research Association, global digital printing will account for more than 25% of the printing business by 2010. In addition, the XML-based standard file format was introduced, and the same procedures can be used to complete the job regardless of the file type. There are also mature and widely used PDF files as international standards, ensuring the consistency of cross-platform operations, which have laid the foundation for the development of digital printing. According to China's development of the "prepress digital, network, printing multi-color, high efficiency, printing fine, automated, high-quality equipment, serialization," the development of the printing industry 28-character principle, indicating that digital printing is now and the future of printing technology A focus of development. In digital printing, how to make post-press processing compatible with prepress and printing is one of the keys to fully improve and develop digital printing.

Digital printing is a completely digital production system. The digital process runs through the entire production process, from the input of information to the printing and even the binding output. Digital printing integrates prepress, printing and postpress. From a system control point of view, it is a seamless all-digital system.

However, in order for digital printing to truly reflect its superiority, in addition to prepress and printing processes, it also requires that postpress processing must be better equipped. Therefore, it is necessary to pay attention to the cooperation of postpress processing of digital printing. Let's talk about the problems that should be paid attention to, such as lamination, binding, and cutting, which are closely related to digital printing.

1. Lamination problem

Laminating is a commonly used post-press finishing and finishing method in publications such as books and periodicals. It has a wide range of applications and is suitable for digitally printed products. Laminating the surface of digital prints, especially after printing a large area on the ground, will help the protection of printed materials in post-press processing, especially cutting or packaging, and enable printing. The product is more beautiful and durable. However, the single-sided lamination of double-sided prints may not be advantageous because the uncoated side may be susceptible to peeling of the print color due to friction during subsequent processing. Many prints are covered with various bright films, matt films, and matt films to achieve distinctive effects. However, digital printing is more suitable for hot printed films. This method is convenient and inexpensive. The film used for the hot film is mainly composed of polyester film and polypropylene film. In general, polypropylene film is required when covering a thin film, and a thicker polyester film may be used for an extra protection. Polyester film is more expensive than polypropylene film, but it has higher strength and can provide better protection for printed products. If the two sides of the printed product need to be coated, the polyester film is preferred. In the lamination of digital printing products, it is mainly necessary to avoid problems such as curling of the printed product after lamination. Therefore, as far as conditions permit, both sides of the substrate should be covered as much as possible; if only one side of the paper is coated and the other side is not covered, curling is very likely to occur. However, it should be noted that for the binding books of wireless binding books can only be coated on one side, do not cover both the seal 2 and the seal 3, otherwise the book block and the cover cannot be firmly bonded. In addition, when the laminator is selected, it is also possible to select a rod that prevents the film from being curled, so that the product after the lamination can be flattened without curling. Avoiding lamination after laminating is also a problem that should be paid attention to in lamination. When the film is hot-laminated on the printed product, the surface of the printed product to be covered with the film must be clean and dust-free. Secondly, it must be noted that the temperature must be appropriate. Too high a temperature may cause the toner to melt, resulting in blistering of the film. In addition, OPP film can be used to ensure that the folded product does not wrinkle after folding. For the selection of coating materials, because the coating may affect the color reproduction of digital printing products, this is mainly because the film used when coating film is not necessarily 100% of the packaging machine 'target = _blank> transparent film, so It will affect the color balance. Therefore, for the sake of safety, you can try to cover a few samples to the customer first to see if the color of the printed product after the lamination meets the requirements of the customer, and then form the laminating process.

2. Bookbinding problem

Products that can be printed by digital printing include books, pamphlets, bids, calendars, etc. Therefore, the commonly used binding methods include wireless glue binding, saddle stitching, lock stitching, iron wire binding, spiral stitching, and circle stitching. It should be noted, however, that it is important to decide which binding method to use before starting to print the job, rather than blindly waiting for it to be considered after printing. Because different binding methods (such as perfect binding and saddle stitching) have different requirements for the layout of pages in the prepress typesetting stage. The decision of which kind of binding method to use should be based primarily on the customer's requirements, the characteristics of the paper used, the orientation of the paper, and the end use of the print.

Before binding, the printed product is generally folded. When the amount of printed paper exceeds 120g, folding a fold before the folding can make the folding easier, and the folded printed sheet is smoother and more beautiful. In fact, regardless of the kind of paper, if the creases are folded before the folding, it can get good results. Crimp creases can be done on a special press creaser machine, which has a desktop machine, but also has a larger press crease, punching dual-use type. If there is an indentation mold, it can also be done on a flat press. In addition, some folding machines themselves have the function of creases. The appearance of cracks in printed images of impressed or folded sheets may be due to the drying of the sheet, and the higher the quantification of the sheet, the more likely the failure is. Therefore, to avoid cracks, the paper should be kept at a proper humidity and not too dry. In addition, folding the paper in the direction of the paper web can also avoid the occurrence of breakage at the crease. If you are processing books and digital printing, the orientation of the paper should be parallel to the spine of the final finished book. Of course, laminating the printed paper can also prevent cracks from appearing at the printed hinges. Indentation should also pay attention to the depth of indentation should be moderate, if you use the indentation machine, should pay attention to speed not open too fast.

At present, domestic digital printing shops use more or flat-booking, especially in the form of wireless glue binding, which is not only beautiful, but also bound firmly. When designing a flat-book, the first thing to note is that there is enough room for binding between the order and the text. For example, when the O-spiral thread has a 3:1 ratio (3 holes per inch), Leave at least 3/8 inch of blank space; when the ratio of holes is 2:1, leave at least 1/2 inch of blank space. This blank refers to the distance between the mouth and the nearest line edge. In order to clearly define the specific location of the processing, the designer is better to understand the changes of the actual printing paper after the digital printing before the digital printing process, which is particularly important for digital printing. Most computer design programs do not consider slight changes in the thickness of printed paper. In digital printing, the color material printed on the surface of the paper causes a change in the thickness of the printed sheet. When the digital printed sheets are bound in tens of pages, the accumulated thickness Changes may make the computer's carefully calculated binding size meaningless. Therefore, we must master the proof change parameters of the actual production paper after digital printing in order to accurately calculate the thickness of the book during the printing design, so as to ensure the proper binding size after the printing process. As with adhesive offset printing, digital adhesives also need to consider the amount of cutting. In addition to leaving a 1/8-inch back allowance on the back of the book, a 1/8-inch cutout is also required on the other three sides of the book. In addition, a 1/4-inch glue area should be left in the lower part of the book cover to prevent glue from seeping into the next book in the binding. The wireless glue binding process also requires that the printed cover should be larger than the text size. Wireless glue binding finishing processing is also an important post-press processing method in the digital printing binding mode. The key to the hardcover process is how to bond the book block to the hard case and produce books that can be stored for long periods of time. Although the cost and time spent on the adhesive binding of wireless adhesives seem to be somewhat out of proportion to the digital printing for the short-run printing market, some post-printing companies have pre-prepared different colors, styles, and differences commonly used in digital printing. Hardcover bookcases of the size are used by digital printers. Therefore, the binding of wireless adhesives has become a common binding method for digital printing.

In wireless glue binding, some books or booklets sometimes appear to be paged off. There are many reasons for this phenomenon. There are reasons for the glue and the reason for the machine. The binders used by digital printers generally include milling backs, gluing, and package covers. Some inexpensive gluebinders do not have the milling and backing process; some binders have milling and backing capabilities. However, the milling and back machining of the spine is not in place, and these will affect the firmness of the glue binding. In addition, the type and quality of the glue also have an impact on the fastness of glue binding. If the temperature is not properly controlled during the glue-binding process, it will also cause the book to be loosened or dropped. In the bookbinding process, the opening time is an important parameter. It refers to the time required for the glue to bond the cover of the book to the book. When a book or booklet is glued on the machine, it will take some time for the glue to continue curing, sometimes up to several hours. Therefore, do not immediately read books immediately after they have been bound on the perfect binding machine. At least 15 minutes later, please read and check them.

In addition, saddle stitching is a fast, efficient, and economical way of binding books and pamphlets. It is also a good choice for most digital prints, especially for guides, booklets, brochures, etc. Thin bookbinding. The binding method can be performed online with other processing methods, and can simultaneously perform post-press processing of collation, folding, binding, and online cutting, and can provide guarantee for fast delivery required for digital printing. However, the thickness of saddle stitching is limited and generally cannot exceed 4mm.

Although the staple binding mode is very good, the binding is time-consuming and costly. Therefore, it is necessary to make careful design and arrangement of India and India in the beginning to ensure the harmony of printing and post-press processing. The following issues should be noted in bookbinding and postpress processing. First, since the ink color material on the digital print only adheres to the surface of the paper, the folding process is easily broken. Therefore, it is best to press the folds before folding.

Spiral binding and stitching also play a role in the binding of digital printing products. Spiral stitching and stitching need to be punched first and then bind the prints into a booklet. The types of spirals or loops used are various, both metallic and plastic; both monochromatic and colored. Spiral is to use a continuous plastic wire or wire from the first hole of the print to the last hole; and the ring is to use a separate ring wire or plastic ring through the hole "clamp" to live Leaflet. Spiral stapling and stitching are characterized by low binding costs and good flatness. A manual A small desk-top punching spiral or bookbinding machine (books with a thickness of 20 to 28 mm can be bound) binds an A4 booklet. It takes 5 minutes. If the number of binding is large, it is better to use a computer-controlled punching and binding machine with a high degree of automation.

Digital printing products can also be punched or drilled. This type of binding is more suitable for papers composed of bound sheets. It is suitable for materials used by students or samples used by sales personnel. In particular, when it is necessary to change some of the contents, only one or more pages of the contents of the changes need to be reprinted, and then the old pages can be replaced after the holes have been completed, without reprinting the entire document or sample. . When using the punch binding method, be careful not to make too much or too thick a punched paper, otherwise it will affect the punch quality. When the drill hole drills, the heat will cause the digitally printed image toner to melt. Care should be taken not to drill excessively. When punching and binding polyester material, punching should be used as far as possible