New development of the most popular flexo gravure

2022-08-02
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New development of flexo printing and gravure printing

flexo printing, gravure printing, offset printing and printing are the four common printing methods for packaging printing. In terms of printing materials such as flexible packaging materials, folding cartons, paper bags and gift wrapping paper, flexo printing and gravure printing have more characteristics. From the development of modern flexo printing and gravure printing, there are many similarities or similarities in the structure and technology of the equipment except for the great differences in plate making. In order to compare and understand the similarities and differences between the two printing methods in terms of equipment structure and new technology, the following will briefly discuss the development and application of flexo and gravure equipment technology in recent years

I. adopt automatic traction and tension adjustment device to realize non-stop roll change/winding.

the new flexo printing machine and gravure printing machine adopt automatic paper receiving mechanism and pneumatic electric tension measurement and adjustment device to ensure constant tension and realize non-stop roll change/winding. In order to ensure that the edge position of the printing material entering the printing part is always correct, for opaque materials such as paper, a deviation correction device composed of a photoelectric scanning head or an ultrasonic sensor should be used. When printing paper or paper jam, sometimes it is necessary to adjust the temperature and humidity. When printing plastic film or aluminum foil, corona treatment device shall be equipped to improve the inking ability of the film surface

II. Independent/direct drive technology is adopted to realize stepless and continuous optional printing length

independent drive technology has been used in gravure printing machine for many years, but it is only limited to traction, coating, compounding and cross cutting units. Now it has been developed to a whole gravure printing machine without mechanical transmission. In each printing unit, a motor drive is used. The plate cylinder is directly driven by the motor to realize the longitudinal registration during the stamping process, and the horizontal registration is controlled by the movement of a stepping motor. The main advantages of the independently driven gravure press are the reduction of mechanical parts (no mechanical transmission shaft and registration compensation roller mechanism are required) and the shortening of the strip length, which is conducive to improving the printing quality and printing speed

the plate cylinder of the old flexo press drives the gear of the plate cylinder through the gear of the impression cylinder to form a synchronous rotation, and the repeated perimeter of the printed matter is the same as the pitch of the gear. In each printing unit of the new flexo press, a motor directly drives the plate cylinder, which solves the problem that the repetition length of printed products is limited by the gear pitch. The digital transmission technology is used to directly drive the printing plate cylinder. When changing printing products with different perimeter, the gear does not need to be changed, and the stepless continuous optional printing length can be realized. Because the digital control is adopted, there is no need to repeat the speed change adjustment, which saves changing the speed and adjusting the gear meshing, so the efficiency is improved

for example, the astraflex CCI satellite type 8-color packaging flexograph newly developed by w&h company adopts the independent motor drive technology, the main drive device, the drive device and traction device of the unwinding/rewinding parts, and the maximum printing speed is 470 M/min. The independently driven flexible packaging gravure printing machine developed by cerudi company has a maximum printing speed of 500 m/min. The flexline vario unit flexographic press developed by BHS company adopts a plate cylinder directly driven by gears, which eliminates the restriction caused by the number of gear teeth and the number of gear teeth. Each printing unit is equipped with its own independent servo drive mechanism and quick roll change system, with a maximum printing speed of 500 m/min. The potopak shaftless gravure printing machine developed by valment rotomec company adopts es (electronic shaft) system and does not use registration compensation roll. It can carry out rapid registration setting in the acceleration and deceleration stages of the machine, which can increase the stability of the machine. The ES concept uses a fully automatic replacement device without any manual intervention of the operator, and the maximum printing speed can reach 650 m/min

with the combination of direct control technology and CI design, the changeability of printing length and the reduction of machine debugging time, the situation that flexo printing was difficult to print on large and changing format in the past has been changed

III. the sleeve type plate cylinder structure is used to realize "rapid plate change"

the plate cylinder of the old flexo printing machine and gravure printing machine basically adopts the integral structure, while the new flexo printing machine and gravure printing machine mostly adopt the sleeve type plate cylinder structure. Because the sleeve type cylinder structure has the advantages of low cost, easy loading and unloading, high flexibility, long service life, convenient storage and high system precision, it can shorten the preparation time, speed up the replacement of printing pieces, and has the function of "quick version change". It is widely used in flexo printing and gravure printing, and will gradually replace the traditional roller. The biggest advantage of the sleeve type plate cylinder is that it can be reused. By using sleeves with different wall thickness, the printing length of the printing plate can be changed

for example, the sleeve system newly developed by w&h company can be used for plate cylinder of all specifications. After printing a product, all specification parts that need to be replaced can be quickly replaced by the operator in the machine, while the plate cylinder mandrel and embossing roller mandrel are always left on the machine. Reusing the roller can not only shorten the preparation time, but also paste the printing plate on the sleeve at any time, which accelerates the replacement of printing pieces and reduces the production cost. The flexpress16 new 8-color satellite flexograph developed by Fischer & krecke company adopts the thin-wall sleeve technology, which has low manufacturing cost and can maintain good radial accuracy during printing. Heliostar 2000 unit gravure printing machine produced by w&h company adopts sleeve technology that highlights gravure cylinder, providing printers with greater flexibility and commercial efficiency

IV. the closed doctor blade system is adopted to reduce environmental pollution, which is conducive to the rapid replacement of the doctor blade. The reverse doctor blade structure is adopted in the quantitative ink supply system, which is suitable for high-speed operation and reduces solvent volatilization and environmental pollution in solvent based inks; The problem of foam accompanying the use of water-based ink is solved

the satellite flexo printer adopts a fully enclosed double scraper ink conveying system. The ink is sprayed to the surface of the roller through the ink port and stored in the ink chamber. The ink is scraped by the reverse scraper, and the positive scraper plays a sealing role. Due to good sealing, it is of great benefit to health and environment. In the fully enclosed system, the scraper, seal, gasket and pressing plate are all installed on a cavity type support, which are pushed to the ceramic roller mechanically (or pneumatically or hydraulically) and applied with a certain pressure, and then 8 Sample size: 0.1 ⑵ 00mm connect the ink delivery pipe and the return pipe to the ink pump and the ink storage container respectively. The closed doctor blade system can ensure the optimal ink volume of the cylinder and the printing plate. The application of laser engraving of high-speed ceramic roller and closed scraper can ensure that the roller and printing plate get the best ink volume. The ink transfer performance of the short ink path system is improved, and the stability of print quality is improved

heliostar 2000 unit gravure printing machine produced by w&h company adopts a newly developed closed splash proof device, which can completely prevent ink splashing in the inking process of the drum. The new satellite gravure printing machine also adopts a device for quickly pressing and replacing the doctor blade, which significantly reduces the time for replacing the doctor blade and improves the quality of the doctor blade. The structure features are as follows: the doctor blade is controlled by a pair of series air cylinders. In the production process, the long stroke air cylinder controls the doctor blade to enter the predetermined working position, and the short stroke air cylinder controls the doctor blade to enter the working position and apply pressure; At the same time, the doctor blade holder is equipped with a turnover mechanism (controlled by a series cylinder) and an eccentric clamping mechanism for the doctor blade. The former can turn the blade holder to a position almost vertical upward, while the latter can clamp the doctor blade accurately, evenly and reliably in a very simple way and the main motor source of the experimental machine is not bright. Therefore, the whole replacement process can be completed on the machine, and the time is greatly shortened. The ink scraping uniformity, the service life of the doctor blade and the drum can be improved

v. automatic plate cylinder cleaning device

at the end of printing, the plate cylinder is automatically cleaned on the machine, which can significantly reduce the workload of manual cleaning and improve the operating environment. The rapid replacement and cleaning system (ecoplus) equipped with heliostar 2000 unit gravure printing machine produced by w&h company significantly reduces the preparation time of the printing machine. The turbolean ink supply and cleaning system adopted by astraflex CCI flexo press can automatically supply ink to the printing parts in sequence and clean the wrinkle roller, cavity ink scraping system, ink pump and ink pipe

VI. quick replacement and positioning system

on the transmission side of gravure printing machine or flexo printing machine, there is a trolley guide rod. The guide rod can accurately control the movement of the trolley and speed up the installation and disassembly of the trolley by lifting and lowering the air cylinder. Portacift manipulator roll change system developed and produced by w&h is used to automatically change plate cylinder and wrinkle roll; It takes only 1 minute to replace one roll. Through the intelligent transmission system and positioning system, the high cost waste can be minimized, which verifies the accurate movement and horizontal registration of the plate cylinder and embossing roller of various color groups

VII. Combined unit structure and diversified post press wiring processing forms

the rcs330 narrow width flexographic press developed by gallus, a partner of Heidelberg, adopts full digital drive technology, full computer control, flexo/silk screen/offset/embossing and other different printing exchange units. The arsoma EM Series unit type flexographic printing machine adopts optional modular unit and open interface structure. It can be flexibly equipped with a variety of post press processing units such as die cutting, hot stamping, marking, polishing, film covering, embossing, and printing control as required

fg500 series flexographic printing machine produced by comprint company can be configured as gravure and flexographic combined printing machine according to user needs

the B250 unit type 6-color narrow width flexographic printer developed by Edale company can select the corresponding configuration according to the processing needs of users to complete the following processing functions, such as holographic anti-counterfeiting, UV glazing, hot stamping, embossing pattern, magnetic stripe pasting, die knife, paper tape punching, slitting and stacking

the new paper gravure printing, wiring compound and die-cutting production line developed by Rudy company is specially used for the printing of cigarette packets and other thick papers. Tachys (quick) satellite flexo printing machine series has a variety of configurations, which can use the line stacked flexo printing unit for polishing, cold/hot coating, lamination and other processes

it can be seen that one-stop production is becoming more and more important, and a single production unit is developing towards an integrated production line

VIII. Apply computer control technology for intelligent operation and management

with advanced computer technology and management system, it can not only realize the monitoring system from single control to centralized control, from single machine control to the whole production line, but also ensure that the equipment will not produce waste materials when registering the equipment under shutdown

using the modular automatic operation system, you can not only pre select the menu, operate the unwinding/winding unit, printing unit and drying unit, but also select the camera "printing" observation module to view the whole printing process on the display screen. Can communication technology is adopted to connect functional modules to exchange information. With the help of modem, select remote fault diagnosis device to help customers

astraflex CCI satellite type 8-color packaging flexograph newly developed by w&h company realizes the coordination between printing station and embossing roller through electronic synchronous adjustment system. The traction devices can be set in proportion and work according to the actual tension conditions, allowing them to lay expensive high-performance continuous fiber materials only where necessary

b250 unit type 6-color narrow width flexographic press produced by Edale company, equipped with printing quality synchronization

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