Manual and machine folding process (on)

Folding methods are manual folding and machine folding. Sheet-fed large-format prints need to be manually or folded to become a signature. The web-fed rotary press has a special folding mechanism, so the printed leaflet is continuously completed on one machine.

First, manual folding

By hand-printing the printed sheets in the order of the page number and the specified width, they are folded into a signature and called a manual folding. With the improvement of the degree of binding mechanization, manual folding is used less and less in books and periodicals printing factories. At present, there are only books with a small number of prints, fractional pages, remedy for endings, and repairs, and there are special folds for signatures. Use hand to complete. The manual folding tool is a folding table and a folding plate. According to the conditions of the trial, the printed pages will be laid out, as shown in Figure 2-14, followed by two-fold, three-fold, and four-fold. After folding a good post, check whether the page number is correct, whether the page number and the crease are neat, whether the signature folded into the signature is centered on the crease, etc., and then fold the folded signature and hit it.

Figure 2-14 Manual folding page layout

Second, machine folding

Machine folding is the folding of the printed sheets, in accordance with the page number sequence and the prescribed format, with the machine folded into a signature.

At present, the commonly used folding machines are composed of three parts: a paper feeding device, a folding mechanism and a receiving mechanism.

The paper feeding device is mainly responsible for separating and conveying the paper, and can accurately convey the printed page to the folding portion.

The folding mechanism is a format in which a printed page sent from the paper feeding device is opened, and is folded into a signature in the order of page numbers.

The paper-receiving mechanism regularly stacks the folded signatures.

1. Folding preparation. The folding mechanism is the most important part of the folding machine, and its assembly accuracy and adjustment accuracy directly affect the quality of the folding. Therefore, before the folding machine is opened, it is necessary to inspect and adjust each part of the folding machine. The main inspection and adjustment parts are:

1 Check whether there is any error in the printed sheets before loading paper. When using the ring-wrapped type, the printed sheets should be placed on the transfer table in a staggered manner and each sheet should be staggered with a spacing of 1.5 to 2 mm. The smallest page number on the printed sheets is On the top, the sign is facing up. When using the platform type paper feeding form, the printed sheets are placed neatly on the stacking table, with the smallest page number facing downwards, and the loading of paper must not affect the speed of paper feeding in time to ensure the smooth running of the folding.

2 check the side gauge and gauge (the position of the front gauge to ensure the horizontal and vertical orientation of the printed sheet;

3 When using the fence type folding machine, according to the folding requirements of different folds, use or close the various fences to complete a fold or fold of a variety of folding modes and folding of the web;

4 Adjust the distance between the folding rollers and the position of the centerline according to the folding method, the thickness of the paper, and the number of pages per fold so that the printed sheets are pressed into both ends of the two folding roll gaps at the same height to ensure the conveyance of the printed sheets. The speed, so that the folder stable, to avoid the printed sheet skew or tear wrinkles; 5 according to adjust the pitch of the folding roller, set the correct position of the folding knife.

The folding machine is also equipped with cutting and punching devices. The role of the cutting device is to divide the full-sheet printed pages into two in one fold process. From the perspective of the performance of the full-sheet knife folding machine, there are two sets of folding devices in the second folding section. After the first folding, only the cutting can be performed for the second folding. Otherwise, the folding cannot be performed. In addition, after the print sheet is cut, the thickness of the book sheet is reduced after the book sheet is folded into a signature, thereby improving the accuracy of the folding. The edge of the trimmed paper edge should be smooth, otherwise the splitter should be checked or replaced. The function of the punching device is to advance a row of long holes on the next folded crease line so as to facilitate the discharge of air in the paper during folding and prevent wrinkles from occurring during folding. The location of the punching knife and the crease must be the same, and the booklet crease should be scratched and cut, but it must not be cut off to avoid loosening and turning pages. The punching device on the four-fold line is used for punching holes for binding, and the glue penetrates through the scratched edge to each page of the booklet to make each page stick to each other.

(to be continued)