Jobbing press

As a platen press, a printing press is known in printing technology, each form a flat surface in which both the press and the counter-pressure body. The flat back pressure body is called a crucible. Often the entire platen press is called shortened pot.

Pressure principle

Platen presses are hand presses or printing machines, which are designed for high pressure and operate on the principle of surface pressure against area. The substrate is passed through the crucible parallel to the printing form and printed on a very high contact pressure in the order of some tens of tons.

In a platen press, the printing form is often at right angles and is inked by a rotating inking roller. The substrate is placed on a provided with a lift pressure pot with a great force in the printing form. The setting of the pressure strength is made ​​on the basis of a rotatable lever system or via a spline system. This has the advantage that the pressure force of the respective printing plate can be adjusted, since each printing plate requires a different pressure level.

The crucible is the movable counter- plate which carries the elevator and is normally used as a paper plant.

Application

While large printing machines with roller technology for sizes up to 100 cm x 140 cm already widespread in the 2000s certainly, can be personalized with a platen press because of the high demands on the flatness of the crucible ( the plate) only formats to about A3 print clean. Therefore platen presses are mainly used for printing small-format products, for example for printing cards, stationery, labels, brochures. However, platen presses can also be for embossing, creasing and punching, even in a joint operation with the printing use.

Construction types

Depending on the arrangement of the printing form, the foundation structure and the movement of the crucible can be distinguished.

• Screw press ( screw press )
• Stanhope press ( toggle press )
• Boston - system: It was built by Isaac Adams and is mainly used in small businesses in commercial printing. The foundation stands upright and secure. The crucible moves about a shaft underneath the foundation to the printing form.
• Liberty System: The foundation set is portable and on a shaft together with the crucible on which the paper is applied. Liberty crucible has two identically structured side of the crucible and the print base, the fold to each other during the printing by a common pivot point.
• Gally System: The set of foundation is laid, while the crucible (paper plant) is performed on a slide. The Gally - platen press has a freely supported crucible, which is supplied via a system of rails, cleats, and push-pull rods parallel to the foundation. The foundation is vertical. The crucible takes just before printing a parallel position to the foundation and pressed by tie rods to the printing form.
• Gordon System: The set of foundation is movable on a shaft, while the crucible (paper plant) is movable on a separate shaft. The crucible and the foundation move about separate axes to each other.

Crucible Machine

The term machine distinguishes between the hand pot from fully automatic system, the automatic platen. When both the paper machine system and the coloring and the display are independent of the operator. Platen machines are still used today for punching and embossing work in modern printing. Example, it is possible to apply holograms on already printed materials. Since press two flat surfaces on each other when the crucible, the printing material is not subjected to mechanical stress, which can lead to cracking or breaking. Therefore, can be provided in this way with holograms and Signierstreifen even plastic cards (like debit cards ).

A distinction is made in automatic platen gripper system with propeller (Original Heidelberg Platen Machine ( windmill ), Grafopress - platen press ) and automatic platen with separate landing system ( such as goblin - machine, PhönixA crucible or Victoria platen press ).

Each crucible type has specific advantages and disadvantages in the printing operation. In Germany, only the Gally ( eg Victoria presses ) and the Boston press were able to prevail ( eg Heidelberger OHT).

The hourly output of the automatic platen is about 5500 printing ( Heidelberg Platen ). This speed can, however, only works that do not need to be in register, are also used. In practice, the 2010s you will rarely experience that a crucible machine is operated at maximum speed. In addition to the registry problem thereby also plays a role that at low speeds, wear is negligible.

Also the multi-color printing is possible, but on the small hand landing crucibles of printing photos is hardly successful. The respective colors are mixed prior to printing and then printed in succession and per color is required, a pressure passage. The advantage of this is the pressure with true color and it is not a simulation by grid points are required. This simplifies the use of special colors, in particular silver or gold. The Heidelberg Platen machine is suitable for printing small color images. The four (one each for yellow, cyan, magenta and black ) printing blocks ( clichés ) but must be screened according to the 4- color printing.

Printing inks for platen presses must have a low tack, so that the printed sheet after printing can be easily taken from the press.

Hand crucible

As hand pot is called small printing presses which operate on the platen principle and are usually driven by muscle power. These presses were mainly used for commercial printing, so for business cards, stationery, sympathy cards, as they were much cheaper than the automatic crucible in acquisition. Therefore, they are operated by small printing.

Hand crucibles were built since 1800 and today make up the majority of all printing presses ever built; they are up to A3 format built in the area of stamp size. Furthermore, the necessary pressing force is too large and the crucible is preferably machine drive. Flywheel -driven hand crucible ( momentum generation by manual drive and gear) are also known as the Hogen forest EXPRESS.

The ink rollers ( up to A4 size, it is usually two pieces, at A3 usually three) are at hand crucible supported in part by the plate inking unit or one or more Verreibewalzen. Hand crucibles are found mainly in the Boston - construction but also as Gally or Liberty crucible. A special design are the very small pot ( for business cards and slightly larger ) that uses the Boston design without the " knee ".

By an upward movement of the handle opens the crucible. Then the paper is manually inserted into the press. Dyeing is carried out via two applicator rolls. The printing form is made ​​with at least two closing tools into the frame. Then it is placed in the mold bed of the crucible and fastened there. The platen is pressed with the hand on the knee lever system to the printing form. After printing, the handle is pushed upwards, and the crucible is opened. The printed sheet can be removed.

History and Development

Around 1450, Johannes Gutenberg has restated its purposes and provided with a mechanism an existing screw press ( wine press / wine ), which allowed to easily bring out shape and paper under the print section of the press and just as easily back out of it.

The first illustration of a press for letterpress printing are 1507 printer character of the Parisian book printer Iodocus Badius: it shows the press of wood, as it has been four and a half centuries still used according to the invention, in their characteristic, still very crude forms. The main parts of such are the frame and the cart. The former consists of two vertical by an upper cross bar ( crown) connected side walls ( cheeks); a lower coupling beam carries the rails on which the cart, ie the part carrying the pressure form of the press, foundation ( of a polished iron plate ), cover and frames by means of crank and Treibgurt rotated in and out of the press (single and extended) is. The pressure is exerted through the crucible of this but, a plate of metal ( the oldest presses made ​​of wood), suspended on hooks rods horizontally at the lower end of a powerful screw, the press spindle, which runs in two located between the pressing walls inside connecting beams. Of those resting in the upper mortises with elastic bearings, while the lower (the bridge ) is fixed; it is above comprises of a strong nut, down she practices with a hardened steel tip their pressure on the center of the crucible in a pan. Horizontally from the center of the spindle is now a strong iron lever with wooden handle ( Bengel vagina) and swing ball, the press Bengel; whose pre- pulling causes the demise of the crucible, respectively. the exercise of pressure.

The lid sits in threads on the carts, as well as the frames on the former. In the cover but be screw heads the punctures, located on fork-like, adjustable iron steel spikes held, in which the sheets are inserted in front of the pressure to the pressure of the second form ( the opposing pressure) to be able to accurately maintain the registers, ie, the pressure must be such that the sides of the front and the back cover perfectly.

The frames shall retain the created sheet in the cover and to protect it from soiling the white permanent bodies; therefore, it is pasted before the start of the pressure completely with paper, and only those places are cut, which really should be printed from the sheet.

To press a part of the color table, on which the thin color spread and rubbed with the platen, but then " carried on " to the mold by repeatedly rolling over with the roller.

The first improver of the press should have been at Nuremberg about a hundred years after Gutenberg, the printing press Danner, by replacing the previously made ​​of wood or iron spindle by such brass. He was succeeded in 1620 the Dutchman Willem Janszoon Blaeu, which (under the so-called bridge ) installed a downward curved, strong resilient plate above the crucible, the same his jerky suddenness took them through her ​​Just Will the pressure and it increased, but at the same time at it is in decline back jumped the press brat.

A to the iron constructed almost in all parts of the papers which gave 1772 first typecaster Wilhelm Haas, and his son of the same enhanced and successor the same.

The Haassche press was modeled a stamping plant, and as with this there was the moving mechanism, the villain, above the cast iron press stand. The spread of Haas 's press was affected by zünftlerische narrow-mindedness.

In April 1789, the court printer Philippe -Denis Pierres presented the first construction of a hinged platen press in Paris. In a box-shaped timber Placed the foundation rested with the printing form. Including a eccentric system was installed. This generated instead of the spindle downforce. The crucible was secured by iron hinges on the frame. The printing turned out just as in previous presses, however, a stronger pressure was exerted. This enabled the complete printing of the printing form. In addition, with this press easier pivoting back to the starting position was possible.

In 1800, Charles Stanhope built a press completely from iron, whose strong -acting mechanism to print a form with a single train allowed, performed with one hand, while the wooden press the two and required pulling with both hands. With the help of the technician Walker the Stanhope press was produced which. , First in the printing Bulmers, a then famous printer in London, was to prepare

Regardless of Stanhope Friedrich Koenig had striven to improve the press. On March 29, 1810, Friedrich Koenig received a patent on its platen machine. In April 1811 the first printing of the "Annual Register" for 1810 in an edition of 3,000 copies was made. The pressure performance of this machine was 400 sheets per hour. Compared to previous platen presses this could produce some innovations.

Furthermore, a milling machinery was used, which guaranteed the drive. There were two application rollers, wherein a printing form inked with its trace and the other at its return pipe. This was achieved by alternately lifting and lowering. Staining was improved by the use of a paint can with a three-fold guide.

The forward and backward movement of the cart was made by drive belt or chain on a Schnurenrad and end rollers. The mechanical system has been changed insofar as that movement of the crucible and of the trolley has been achieved, which allowed a twice resting of the cart during the upward and downward movement of the crucible,

This first platen machine of Friedrich Koenig could not prevail, and a year later she was newly developed. After years of toil, he came to the invention of high-speed press, in which the principle of the platen press was "flat to flat" " flat against around " is replaced by the new principle. But this was also the first only a hand press with mechanical coloring and even such operation.

A very strong acting press created in 1817, the American George Clymer in the Columbia press, in which the screw is replaced by a combined leverage and even made ​​the press for printing the most severe forms suitable for the job but was much easier for the printer by the admirably constructed mechanism.

" Improved constructions " followed quickly from now, so the " Scottish Press " by John Ruthven, in which not, as with all used so far, the crucible, but the foundation was laid, while the former was on rolls back and forth. For general acceptance but only first pressing of the Americans W. Hagar and S. Rust, the Hagarpresse and the Washington press, former first built in Germany by Christian Dingler in Zweibrücken and named after him Dinglerpresse.

It exerts pressure by straightening of one or more knees while tightening the villain and looks very strong with the simplest construction. The same principles are the since Dingler in Germany by numerous other manufacturers balers, to reason, and also the Albionpresse, now commonly used in England and first built by RC Cope, is only a simplified and improved Hagarpresse, the basic principles of the press builders in Belgium have been and France also adopted and applied per the needs.

The high-speed presses and Accidenzmaschinen now had the hand presses only allowed a very limited field of work.