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Precautions for common book printing processes!

Time:2025-07-17 Views:4
Digital printing has become a key focus of current and future printing technology development. But in order for digital printing to truly demonstrate its superiority, in addition to pre press and printing processes, it also requires better supporting post press processing. Therefore, attention should be paid to the coordination of post press processing in digital printing. The following are precautions for laminating, binding, cutting, and other processes closely related to digital printing post-processing, for your reference.

Film covering issue

Film coating is a commonly used post press processing and finishing method for printed materials such as books and periodicals, with a wide range of applications and is also suitable for digital printing products. Coating the surface of digital printed materials, especially after printing large areas of solid materials, will help protect the printed materials during post press processing, especially during cutting or packaging, and make them more beautiful and durable. However, single-sided coating may not be advantageous for double-sided printed products, as the uncoated side may be prone to peeling of printing pigments due to friction during subsequent processing.

Many printed products are coated with various glossy films, matte films, and matte films on the surface in pursuit of unique effects. But it is more suitable to use hot film coating for digital printing products, which is convenient to use and inexpensive. The films used for hot laminating mainly include polyester film and polypropylene film. Generally, polypropylene film is required when covering thinner films, and thicker polyester film can be used for printed products that require additional protection. Polyester film is more expensive than polypropylene film, but it has higher strength and can provide better protection for printed products. If both sides of the printed product need to be coated, it is best to use polyester film.

In the lamination of digital printing products, various problems are often encountered, and the measures taken for different problems are also different.

1. Curling of printed products after lamination

In the lamination of digital printing products, it is common to encounter problems such as curling of the printed product after lamination. Therefore, if conditions permit, try to film both sides of the printing material as much as possible; If only one side of the paper is coated with film and the other side is not coated, it is very easy to cause curling. However, it should be noted that the cover of wireless adhesive bound books can only be laminated on one side. Do not also film the second and third covers, otherwise the book core and cover cannot be firmly adhered. In addition, when choosing a laminating machine, a rod can also be selected to prevent the laminated printed products from curling, which can ensure that the laminated products are flat and not curled.

2. Blistering of printed products after lamination

Avoiding foaming of products after lamination is also an issue that should be taken seriously in lamination. When hot laminating printed materials, the first thing to ensure is that the surface of the printed material to be coated is clean and dust-free. Secondly, attention should be paid to the appropriate temperature, as high temperatures can easily melt the toner and cause the film to bubble.

3. Wrinkles in the printed product after lamination

In addition, OPP film can be used to prevent wrinkles in the folded product after lamination. For the selection of laminating materials, laminating may affect the color reproduction of digital printed products. This is mainly because the film used for laminating is not necessarily 100% transparent, which can have an impact on color balance. Therefore, for safety reasons, you can first try to cover a few samples for the customer to see if the color of the printed product after lamination meets their requirements, and then proceed with lamination processing formally.

Binding issues

Digital printing can print products such as books, booklets, bidding documents, calendars, etc. Therefore, commonly used binding methods include wireless adhesive binding, saddle stitching binding, wire binding, spiral binding, and wire binding. But it should be noted that it is important to decide which binding method to use before starting to print the live parts, rather than blindly waiting until the printing is complete before considering which binding method to use. Because different binding methods (such as wireless glue binding and horse riding binding) have different requirements for page arrangement during the prepress layout stage. The decision on which binding method to use should mainly be based on the customer‘s requirements, the characteristics of the paper used, the direction of the paper strands, and the ultimate use of the printed material.

Before binding, printed materials usually need to be folded. When the weight of the printed paper exceeds 120g, pressing the creases before folding can make folding easier, resulting in smoother and more aesthetically pleasing printed sheets. In fact, regardless of the type of paper, pressing the creases before folding can achieve good results. Creasing can be done on specialized creasing machines, including desktop computers and larger creasing and punching dual-purpose models. If there is an indentation mold, the creasing work can also be completed on a flat press machine.

In addition, some folding machines themselves have the function of pressing creases. Cracks in the printed image after indentation or folding may be caused by the dryness of the paper, and the higher the weight of the paper, the more likely this fault is to occur. Therefore, to avoid cracking, the paper should be kept at an appropriate humidity and not too dry.

In addition, folding the paper along the direction of the paper strands during folding can also avoid breakage at the creases. If it is processing books and periodicals, when digital printing, the direction of the paper strands should be parallel to the spine direction of the final finished book. Of course, laminating the printed paper can also prevent cracks from appearing at the folds of the printed product. When indentation, attention should also be paid to the moderate depth of the indentation. If using an indentation machine, the speed should not be driven too fast.

1.Wireless adhesive binding

At present, most digital printing shops in China still use flat binding, especially wireless adhesive binding. The books bound by adhesive binding are not only beautiful, but also firmly bound. When designing a paperback book, the first thing to pay attention to is leaving enough binding space between the binding opening and the main text. For example, when the thread hole ratio of the O-shaped spiral wire is 3:1 (referring to 3 holes per inch), at least 3/8 inch of blank 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 refers to the distance between the ordering port and the nearest line hole edge. In order to clarify the specific location of flat cutting processing, it is best for designers to consult with post press processors about the actual printing paper before digital printing processing.

The changes after digital printing are particularly important for digital printed materials. Most computer design programs do not take into account the small changes in paper thickness after printing, and in digital printing, the pigments printed on the surface of the paper can cause changes in the thickness of the printed sheet. When binding dozens of digital printed sheets, the accumulated thickness changes may render the computer‘s carefully calculated binding size meaningless. Therefore, it is necessary to master the parameters of sample changes of actual production paper after digital printing in order to accurately calculate the thickness of books during printing design and ensure that the appropriate binding size is obtained after post printing processing.

Like the wireless adhesive binding process in offset printing, the wireless adhesive binding of digital printed materials also needs to consider the cutting amount of binding. In addition to leaving a milling allowance of 1/8 inch on the back of the book, a cutting allowance of 1/8 inch should also be left on the other three sides of the book. In addition, a 1/4 inch adhesive area should be left at the bottom of the book cover to prevent the adhesive from seeping onto the next book during binding. Wireless adhesive binding processing also requires that when printing the bleeding cover, it should be slightly larger than the size of the main text.

2.Hardcover wireless adhesive binding 

Wireless adhesive binding is also an important post press processing method in digital printing and binding. The key to hardcover craftsmanship is how to firmly bond the book core with the hard book shell, producing books that can be stored for a long time. Although the cost and time required for wireless adhesive binding of hardcover may seem somewhat disproportionate to digital printing for the short print market, some post press binding companies have pre fabricated hardcover book covers in different colors, styles, and sizes commonly used in digital printing for digital printers to choose from. Therefore, wireless adhesive binding of hardcover has also become a commonly used binding method in digital printing.

In wireless adhesive binding, some books or booklets sometimes have the phenomenon of page dropping. There are many reasons for this phenomenon, including adhesive reasons and machine reasons. The wireless glue binding machine used by digital printers generally includes several steps such as milling the back, gluing, and wrapping the cover. Some inexpensive glue binding machines do not even have the milling back process; Some glue binding machines have milling back function, but the milling back processing of the spine is not in place, which will affect the firmness of the glue binding.

In addition, the type and quality of glue also have an impact on the fastness of the binding process. Improper temperature control during the binding process can also lead to loose or dropped pages in the bound book. In the adhesive binding process, the opening time is an important parameter, which refers to the time required for the adhesive to firmly bond the book cover to the book. After the book or booklet is glued onto the machine, the glue still needs a certain amount of time to continue curing, sometimes up to several hours. Therefore, do not immediately flip through the book after it has been bound on the glue binding machine. It should be checked and checked at least 15 minutes later.

3.Saddle stitch binding

In addition, horse riding binding is a fast, efficient, and economical way to bind books and booklets, and is also a good choice for most digital printed materials, especially suitable for binding thinner books such as guides, booklets, and brochures. This binding method can be combined with other processing methods, and can simultaneously perform post press processing such as page matching, folding, binding, and online cutting, providing a guarantee for fast delivery required for digital printing. But the thickness for horseback riding is limited and generally cannot exceed 4mm.

4.Thread stitching

Although the binding method of lockstitch has good firmness, its binding cost is high and time-consuming. Therefore, it is necessary to carefully design and arrange the printing process from the beginning in order to ensure the harmony and consistency between printing and post printing processing. Attention should be paid to the following issues during binding and post printing processing. Firstly, due to the fact that ink pigments on digital printed materials only adhere to the surface of the paper, folding processing is prone to cracking. Therefore, it is best to press the creases before folding processing.

5.Spiral and Wire Binding

Spiral binding and wire binding also play a certain role in the binding of digital printing products. Spiral binding and wire binding both require punching holes before binding the printed materials into a booklet. The types and specifications of spiral or wire  lines used are diverse, including metal and plastic materials; There are both monochrome and color options. Spiral stitching is the process of threading a continuous plastic or metal wire from the first hole to the last hole in a printed product; Circle binding, on the other hand, involves using independent circular iron wires or plastic rings to "clamp" the printed single page through circular holes. The characteristics of spiral binding and circle binding are low binding cost and good flatness. It takes about 5 minutes to use a manual small desktop punching spiral binding or circle binding machine (which can bind booklets with a thickness of 20-28mm) to bind an A4 booklet. If there are a large number of bindings, it is best to choose a computer-controlled punching binding machine with high automation.

Shenzhen Gold Sun Color Printing Factory is a China based book manufacturer, very good at printing hardcover book, photo book, story book, photo album, Printing paper, coloring book, packaging & printing services,  Labels, printing stickers, anti-water labels, vinyl label, custom label book , softcover book, custom book printing hardcover, mini book, photobook printing, hardcover book, , board books, color sticker books, sticker books, packaging boxes for small business, custom book, children board books, kids book, journals, notebooks, Agenda, Customs Calendar, magazines, color books, cookbooks, etc. With ISO-2001 and CE certificate, Gold Sun offers very good price and outstanding service.

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