Digital Printing Postpress Q&A (11-21)

11. What should you watch out for when choosing a finishing device?

When purchasing the binding equipment, it is necessary to check whether the paper conveying mechanism (such as paper guide rollers, rollers, etc.) is of good quality. If the quality of the rollers is not good, the printed paper can be easily damaged. The transfer roller and the paper guide roller also make Paper generates static electricity.

12. Why does a book or book that has been glued off sometimes fall off?

There are many reasons for the page drop, the reason 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, there is a parameter that is important, the open time, which 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 read it immediately after the book has been stapled on the perfect binder. At least 15 minutes later, please read it and check it.

In short, in the face of the market with different prices, different quality of the perfect binding machine, must pay attention to meet the binding requirements of your printing products.

13. What kind of printed product is bound for punch binding?

Punching or boring binding methods are more suitable for binding documents consisting of sheets of one page, which are applicable to student materials or sales staff samples. 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, the punched paper should not be too thick or too thick, otherwise it will affect the quality of punching. 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 the polyester material is to be punched and bound, the punching process should be used as far as possible without drilling, because the heat generated by the drilling easily melts and sticks the polyester material.

14. What is the difference between a spiral and a circle?

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.

15. Can digital printing products also be coated?

can. In order to make the prints more beautiful and durable, many prints are covered with various bright films, matt films, and matt films to achieve distinctive effects. Digitally-printed prints are usually hot-laminated. This method is easy to use and inexpensive.

16. What is the stress when choosing a film for laminating?

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.

17. How to avoid curling of the printed product after lamination?

First of all, if possible, cover both sides of the printing material 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, there is one point to remind everyone 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.

18. How to avoid the product after lamination is not blistering?

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.

19. Does lamination affect the color reproduction of digital prints?

There may be some impact, 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 coating is in line with the customer's requirements, and then form the film.

20. What is the effect of die cutting on digital printing products? Do digital printers need to add a die-cutting machine?

Die-cutting can make the final printed product attract people's attention with special shape or prominent local features, and can increase the added value of the product. Whether or not digital printers need to install a die-cutting machine depends on how large the amount of jobs they process is. If not, the die-cutting machine will be idle and wasteful. Selecting a die-cutting machine should pay attention to the processing requirements for your prints. You can use a platform die-cutter when you are cutting thicker paper, and a rotary die-cutter when you are cutting a thin paper.

21. In addition to the methods and requirements for post-press processing that are emphasized in the pre-printing design phase, what issues should digital printers pay attention to after printing?

It is very important to communicate and communicate with each other. This can avoid many problems. Pre-press designers, printers and post-press processing workers should strengthen communication. Check whether the layout design meets the requirements of post-press processing. In addition, there are several points to note: 1 to select the paper suitable for printing needs, check the paper format, quantitative compliance with the requirements; 2 in the post-press processing process, should always check the processing results of each process to ensure the processing of printed products Achieve a higher standard; 3 Ask questions before thinking about selecting and printing processing equipment. Think twice before proceeding, depending on the operation demonstration of the machine, confirm that it can meet the speed and quality you require, and can satisfy your postpress Processing requirements. It depends on whether the dealer of the equipment can provide you with spare parts and consumables supply (such as indentation molds, ordering heads, glue, film for laminating, etc.) besides selling equipment.

Most of the digital printer's folding requirements. Do not open the machine too fast when folding, so as not to cause paper deformation or wrinkling. In order to avoid double-sheets and other paper-feeding failures caused by static electricity, anti-static bars should be installed on the folder. In addition, if the indoor humidity is too low, it will cause the paper to break when the paper breaks, so pay attention to maintain the appropriate humidity. For printed sheets that require continuous folding, fold indentations and then fold the sheet first to avoid wrinkles or cracks on the sheet.