Folding machine
The folding machine is a machine that is used in industrial bookbinding . In the case of large print runs, it is used for the economically efficient folding of finished products such as booklets, folders and maps as well as unfinished printed sheets that are finished after being folded by other machines.
History and today's use
In 1847 the Englishman Thomas Birchall of Ribbleton Hall in Lancaster patented a mechanical construction for folding newspapers. The inventor Black's first folding machine was presented at the London World's Fair in 1851 . The construction still consisted of wooden parts and was only set up for two folds; it folded almost 1,000 sheets per hour. After Friedrich Koenig had invented the high-speed press and thus revolutionized book printing at the beginning of the century, the first web-fed rotary press went into operation in 1863 . The Swiss company Martini in Frauenfeld has been involved in the construction of folding machines since 1860. The Leipziger Maschinenfabrik Hugo Koch presented the first folding machine at a trade fair of the Börsenverein in 1862. The introduction of halftone printing in 1882 simplified the reproduction of photographs, and book production increased rapidly as a result. With the establishment of the company Preusse & Co in Leipzig, the graphic industry was established in the German Empire . In 1885 the first thread sewing machines were put into operation in the Reich . From 1890, the first folding machines in which the sheets had to be created by hand were running in large German bookbinders. Almost 20,000 sheets could be folded within 12 hours - around six times the daily output of a skilled hand folder. Gustav Kleim constructed the first automatic knife folding machine in 1893, which was marketed by the Brehmer brothers in 1895.
Today's models of folding machines are so technically mature that even semi-automatic models can process up to 7000 sheets per hour with parallel folding. A folding machine folds a flat printed sheet ( flat sheet ), which beforehand can have twice, four, eight or more times the format of the finished printed product . The finished sheets are fed to further industrial production and processed by modern saddle stitchers , thread sewing machines or perfect binders .
Furnishing functions
Bow system
The stack of sheets to be processed is delivered to the folding machine on pallets after the printing process. Depending on the type of construction, the sheets are placed manually on a round or flat pile feeder or fed directly via a pallet feeder.
At the beginning of the folding process, the right folding system is essential in order to set up the machine correctly for bookbinding further processing. A registration mark pre-marked by the printer on the sheet gives the skilled workers in the print finishing department (bookbinding) the necessary instructions on which side of the open sheet must be placed on the folding machine. The skilled worker must not set the system of his folding machine the wrong way round if he wants to prevent the specified page numbers from remaining correctly arranged. This means that the sheets must always run into the folding machine with the same paper edge first. That is why the printing system is specified by prepress, and the printer is also bound by this specification. The system is always the same each individual sheet represents especially when printing ensure that the predetermined set of levels according to the folding operation always at the same point is at the opposite orientation of the sheet can be compensated for but smaller differences in length during folding. There is a simple rule for a maximum of 16-page products. The system should always be on pages 3/4 of the sheet, except for 16 pages in portrait format. There it is on pages 5/6.
The above example shows the page distribution for the most frequently used cross fold for a 16-page printed sheet. Eight pages go on the front and eight pages on the back. After printing, the paper is first folded vertically (page two falls on page three), then horizontally (page four falls on page five) and finally vertically again (page nine falls on page eight). The break on the head and back of the printed sheet produced by the folding machine also serves as a new system when further processing is required. The type area of the folded sheets are now exactly on top of each other. Additional cutting marks and fold marks attached outside the layout make the work of the machine operator easier when folding; these marks will no longer be visible after the subsequent final trimming.
Folding technology and workflow
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The individual sheets are drawn into the first folder by means of suction air generated by compressors . To ensure that only one sheet is fed in at a time, a double sheet control checks that it is fed correctly. For the further transport of the sheet, inclined transport rollers are responsible on all folding units, which guide the product to the respective stop setting, where the folding is then carried out using the sword or buckle folding system. In the case of the buckle folding machine, roughly speaking, the first folder stands for the parallel folds and each connected additional folder for further cross folds. Up to 6 pockets can be used per folder, which are arranged alternately up and down. The folding process in buckle folding machines is based on the principle of the buckle fold . With this system, three folding rollers and a folding pocket always form the unit required to form a fold. The three folding rollers involved in the process are roughly at right angles to each other, the respective folding pocket is located on the open side, in which the incoming sheet of paper is stopped by a presented system. The front part of the folding pocket opposite the three folding rollers is rounded and is called the pocket mouth, which in turn is divided into an upper and lower lip. Past the upper lip, the sheet meets the lower lip of the front pocket in the so-called compression space , is deflected from its previous direction and looks for its exit in the next folding unit. Due to the front position of the pocket mouth, which is already pre-bent and pushed by the rear part of the sheet that has been transported, the front part of the sheet gets into the opposing pairs of the following rolling unit, is drawn in and, as it were, rolled out at the fold. The intended fracture of the paper sheet can be obtained by precisely mounted on the rollers Riller - or perforator are pre-processed, which further facilitates the following Falzakt.
The possibilities of the types of folds with the pocket fold are almost limitless by replacing the pockets with so-called switches or by using additional units. The folding units following the first folding station as in the modular system can be changed in their position according to the requirements: linearly as an additional parallel folding station for the production of several Leporello folds or at right angles to the preceding station, so that the usual cross-fold folds can also be carried out. Depending on the selected position of the individual folding units, the most diverse folding variants can be implemented. Each folding unit has its own drive so that, due to the shorter infeed length of the paper sheet, the second and third stations can be produced at the reduced running speed required in each case. Modern additional units enable today's folding machines to join the sheets into one another using computer-controlled hot-melt glue systems, so that subsequent stapling via the saddle stitcher is no longer necessary. Addressing systems can also be attached and integrated into the folding process using an inkjet process.
When the sheets of paper have been folded to the intended final format in the last folding unit, they are fed to a cross delivery or directly to the next work process via conveyor belts . In small businesses, after leaving the last folder, the sheets are fed into a press station (pack-like output) or transported to a stream delivery (fan-like output), pushed straight by hand and placed on pallets for further processing.
Folding systems
- Knife folding machines
In the last century the most common archetype of a folding machine, these folding systems proved their worth particularly with the criss- cross and three-folds of larger types of printing. Because of the long set-up time, these machines have now been replaced by the more flexible pocket folding systems. The knife fold principle consists essentially in the fact that a sword is guided in parallel in two rollers running against one another and the sheet in between is pulled through and folded. This type of folding is also frequently used today in combination folding systems.
- Pocket folding machines
The most common modern machine type, mostly equipped with three folding units, in the main unit equipped with four or even six pockets. Machines of this type can be almost any type of zigzag - winding and - gatefolding manufacture and depending on the number of connected crossfolds folding devices with 8, 16 or 32 pages process. With additional units it is also possible to enrich the machine with knife hemming systems.
- Combined folding machines
Machines that combine both the pocket folding system and the knife folding system.
Well-known manufacturers
-
Stahl (since 1999 Heidelberger Druckmaschinen )
- Tree folder
-
MBO mechanical engineering Oppenweiler Binder
- Herzog + Heymann GmbH
- GUK folding machines Griesser & Kunzmann GmbH & Co. KG
- FRAMA
- Francotyp-Postalia
- Neopost
See also
literature
- Ing.JR Jungmayer: Reproduction and printing technology, Leykam Verlag, Graz
- Alfred Furier: Folding in Practice, STAHL GmbH & Co, Ludwigsburg 1983
