Digital Printing's Postpress Methods and Technical Points

A few years ago, digital printing was still a new thing, and there was still a long way to go from commercial production. There was indeed a big gap between the quality of digital printing and people's requirements, and the production efficiency was also very low, and it was difficult to meet people's needs.

However, the speed of change and development of digital printing has exceeded people's imagination in recent years. Today, the production efficiency of digital printing has been greatly improved, and the range of printing materials has become wider and wider. The print quality and results of some printed materials have to be praised. Digital printing has indeed become one of the most attractive printing methods.

However, from the point of view of binding and post-press processing, there are still some problems that cannot be ignored in the post-press processing of digital printing. This article attempts to discuss the post-press processing methods of digital printing in order to provide readers with some references.

Thinking about postpress processing from prepress design

Prepress design will facilitate the successful completion of digital printing and finishing. In digital printing, the prepress design has a great influence on the cost of postpress processing. Since digital printing uses a limited number of paper sizes and a large number of digital prints are printed on one side, the following factors should also be considered in addition to the prepress design that requires digital printing to make the most effective use of paper.

1. The direction of the paper

When possible, try to align the orientation of the sheet with the back of the finished book. Due to the particularity of the combination of the color material and the paper on the surface of the digital printing paper, if the page is folded in the horizontal direction, the image will easily break at the folding position. Therefore, digital prints should take into account the post-press processing in the prepress design.

2. Image location on printed sheets

Usually, many digital prints are designed with the image in the middle of the print sheet, but when printed and processed after printing, it is found that doing so wastes a lot of time and money. For example, design a 6-inch by 9-inch image in the middle of a sheet of 8.5 inches by 11 inches. When cutting, you need to cut all four sides of the sheet; but if you place the image somewhere For the corners (eg, the upper left corner), only the two sides need to be cut, thereby saving the post-press processing time and reducing the printing cost. However, if the other two sides of the image are bleeding designs, you still need to trim all four sides of the sheet.

Stapling and finishing

Only carefully designed and arranged for India and India at the beginning can we ensure the consistency of printing and postpress processing. In production, the following points should be noted.

1.folding

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.

Laminated film

Laminating the surface of digital prints, especially after printing a large area on the ground, will be helpful for the protection of printed materials in post-press processing, especially during cutting or packaging. . It is not necessarily beneficial to apply a single-sided film to a double-sided print, because one side of the uncoated film may be more susceptible to peeling of the printed toner due to friction.

3. Saddle stitching

Saddle stitching is a good choice for most digital prints and is particularly suitable for the binding of thinner books such as guides, booklets and brochures. The binding method is economical and practical, and can be carried out online with other processing methods. Simultaneous post-press processing of folding, folding, binding, and online cutting can be performed, which can provide guarantee for fast delivery required by digital printing.

4. Set flat

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.

5. Wireless glue binding

As with adhesive offset printing, digital glue bindings 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. Adhesive adhesive processing also requires that the print cover should be larger than the text size.

6. Wireless adhesive binding hardcover

Whether you believe it or not, wireless glue binding is also an important post-printing method in digital printing binding. The key to the hardcover process is how to securely 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 required for adhesive binding of wireless glue seem to be somewhat out of proportion to the digital printing for the short-run printing market, some post-print binding companies prefabricate different colors, styles, and differences commonly used in digital printing. The size of the hardcover bookcase is used by digital printers. Therefore, wireless adhesive binding has also become a common binding method for digital printing.

Integrated Finishing Solutions

The quality and speed of digital printing make it even more compelling, and it has become one of the increasingly widely used printing methods. Most digital prints require almost all post-press binding processes to become practical print products, and most postpresses The processing technology can be applied to the digital printing after printing.

At present, the main post-press processing equipment for digital printing includes folding machines, double loops, plastic ring binders, wireless glue binders, saddle stitchers and collating machines. Among them, folding machines, glue binding machines, and saddle-stitching machines can be divided into floor-standing and table-top models, but usually the saddle-stitching machines are floor-standing. Collating machines include both vertical and horizontal types, of which most are vertical.

With the rapid development of digital printing, there are also increasingly active manufacturers of post-press processing equipment for digital printing, such as Heidelberg, Mailer Martini, MBO, MBM, Baum, Duplo, Spiel Associates, Standard Finishing, CP Bourg, Southwest Plastic. Binding, James Burn International, Powis Parker, Rosback, GBR, Brackett, GBC, Best Graphics, Riso, and Ab Dick.

It should be clearly pointed out that not all printers or post-printers can control digital printing's post-press processing. If a company has a wealth of digital printing knowledge, understands the special nature of digital prints, and has a variety of post-press processing equipment, with strong production and processing capabilities and a wealth of post-press processing experience, then the digital printing of post-press processing It is no longer a difficult job.