1. Development level of sheet-fed offset printing equipment
In principle, sheet-fed offset printing is exactly the same as web offset printing. One of their differences lies in the products. Web offset printing is mainly used to print newspaper and book content. Sheet-fed offset printing is mainly used to print colorful exquisite prints such as book covers, picture albums, packaging boxes, etc., which is what we often say. Printing, which determines that it is more complex, finer and stricter than rotary offset printing in the entire printing process. In the development of sheet-fed offset printing presses, there are several important technical improvements that have attracted attention and made significant contributions to the improvement of their automation functions.
(1) Double-sided printing With the gradual solution of problems related to double-sided printing technology (such as printing quality, dirty, etc.) Q, double-sided multi-color printing equipment has become the main equipment of some printing equipment manufacturers. Especially its high efficiency is welcomed by the majority of users. At present, double-sided printing mainly focuses on two technologies: flipping and non-flipping. For the domestic market, offset printing equipment without turning over will be more and more popular with users. At present, almost all international manufacturers have launched their own unique double-sided printing equipment. Such as Heidelberg Speedmaster SM52 ten-color reversing printing press and its new Speedo XL105 double-sided printing machine with paper reversing device exhibited on drupa2008, Komori Lithrone S40SP, Akiyama new product MEGA Jp5p540DC + RF big folio 5 + 5 Sheet-fed double-sided multicolor offset printing machine, etc.
⑵Large format printing is in the format design. Nowadays, a variety of offset printing machines are available, and the materials involved in printing products are more extensive, and the large format equipment is unique, which can realize paper, plastic and micro corrugated cardboard. The ultra-large format direct printing, even the printing of large transparent light box advertising materials, etc. In recent years, the large-format offset press market has attracted considerable attention. The ultra-large-format printing equipment such as Roland 900XXL and KBA Rapida 205 have injected strong vitality into the printing market. In 2008, Heidelberg was not far behind, launching Speedmaster XL142 and 162 large format offset presses on drupa2008. In terms of domestic manufacturers, Beiren also launched the BEIREN800 large-format offset press, and Henan Xinji is determined to become the first manufacturer of large-format offset presses (which can customize large-format offset press products for customers. There have been several successful cases. Market welcome), in addition, Jiangsu Chang? N and Jiangxi Zhongjing also have large-format offset press representative products, showing that this market is the degree of attention of major manufacturers.
(3) No side gauge Before the paper reaches the front gauge, the paper position is monitored by photoelectric sensor devices installed on both sides of the paper conveying table, and the information is fed back to the central controller, and then sent to the control roller servo motor of the delivery roller To complete the lateral positioning of the row of teeth. Because there is no side gauge, the operator does not need to do any side gauge adjustment, which can effectively reduce the preparation time of the machine by 25%. KBA's DriveTronic SIS, a sideless paper feeder, eliminates all manual intervention in the process of changing substrates and ensures that the paper runs more smoothly than mechanical or pneumatic systems.
â‘· Shaftless drive The shaftless drive technology realizes the synchronous control of the sheet-fed printing unit and the paper conveyor, and realizes the control of the four high-precision servo motors of the paper conveyor, respectively controlling the separation nozzle and the nozzle of the separation head The paper suction nozzle, paper conveying belt and front stopper tongue, as well as the movement of the main and auxiliary paper feeding tables, greatly improve the accuracy and stability of the system movement, and can be separated from the thin paper without replacing any parts To thick cardboard, corrugated cardboard and plastic sheets and other substrates. Manroland, Heidelberg, KBA, Beiren and other high-end sheetfed offset presses have adopted shaftless transmission technology.
⑸ Imprinting, anti-sticking treatment of transfer cylinder For single-sided double-sided offset printing machine, after printing one side, the other side will be printed quickly, the interval and distance are very short. Therefore, the unprinted ink on the first side tends to stick to the impression cylinder and paper transfer cylinder of the second side printing color group, causing problems such as sticking, cross-coloring, and ghosting. Therefore, the surfaces of the impression cylinder and paper transfer cylinder of the second-side printing unit must be properly treated. Replaceable fiber sleeves and various surfaces can be installed on the impression cylinder and paper transfer cylinder after special treatment to form a jacket with a rough surface and ink repellency, but it must be cleaned for a period of time.
⑹ Non-stop plate change and cleaning technology Non-stop plate change can replace the printing plate of non-printing printing unit when other printing units are working normally, and clean other cylinders and ink systems as well as various Presets greatly reduce auxiliary time. Currently, the DriveTronic SPC special plate cylinder drive system introduced by KBA Rapida 105 can synchronize all printing plates in 60 seconds; the high-speed fully automatic plate changing device and non-stop plate unloading system of Komori Lithrone SX40 printing press can speed up The plate-changing speed is changed to Q6 printing plates in 2 minutes, and the plate-changing speed is increased by 35%.
⑺When the multi-color machine with same-phase plate-changing machine stops, due to the different phase angle of the plate cylinder, it can only change plates one by one. Qiushan adopts its own in-phase technology, and the work of changing the version can be carried out at the same time. Regardless of the number of units, the entire plate change process is the same as the time to change a printing plate, which is a very valuable attempt to shorten the plate change time.
â‘» Non-stop paper feeding and paper collecting high-speed offset printing machine In order to reduce the time of replacing the paper stack and improve the efficiency of the machine, a non-stop paper feeding and paper collecting device is provided. Now both non-stop paper feeding and paper receiving are available as options, and manufacturers of high-speed offset printing equipment can basically provide them.
⑼On-line laminating device Now the sheet-fed offset printing press can also realize on-line laminating. The first unit of the printing press prints adhesive on the substrate, and the rubber cylinder of the second unit is wrapped with a film, and the film is glued to the corresponding part when the printing material passes by. This process is completed at normal temperature, which completely avoids the influence of temperature on the film and printing materials.
⑽Online online slitting In order to avoid small and medium-sized prints printed on large-format offset presses before slitting, Manroland and KBA have launched online slitting devices. The on-line slitting device is generally installed on the impression cylinder of the last unit. The slitting device is composed of a slitting knife and a steel belt on the impression cylinder. The slitted paper is collected and sent out in two paper piles. On-line slitting is suitable for small or medium quantity of live parts, and the paper weight is below 450g / m2, which is helpful to reduce the abrasion of slitting knife and steel belt. It is more cost-effective to cut with offline paper cutters when printing large volumes and running continuously.
⑾Post-press connection processing Post-press connection processing was originally the advantage of web printing machines such as flexo printing machines, gravure printing machines and form printing machines. Now, sheet-fed offset printing presses have also added these functions, such as coating and drying. , Hot stamping, die cutting, creasing, embossing, window opening, punching, slitting and folding.
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