Thin printing process - the system is the key

- Application of halftone screen printing of nyloflex photosensitive resin plates for direct printing on corrugated board to corrugated board is becoming more and more widespread. The advanced technology in packaging and trademark printing - thin printing technology is also increasingly favored by direct printers of corrugated paperboard due to its excellent printing quality, such as small dot enlargement, fine whitening, and clear halftone. In the direct printing of corrugated board, thin plates refer to plates with a thickness of 1.7 mm, 2.54 mm, and 2.84 mm (including the thickness of the elastic pad), while thick plates (including pad thickness) refer to 3.18 mm and 3.94 mm. Plates, they can be used for printing corrugated cardboard. However, there is a limit to the number of plates that can be used in a particular press. It is related to the undercut depth of the machine. However, the depth of the groove of the printing machine is generally between 4.5mm and 7.0mm, and there is enough room for selection. Experiments show that FAII 170, FARII 254, and FAII 284 plates with a plate emboss depth of 1.0 mm perform well in direct printing on corrugated cardboard, with fewer dot gains, insignificant board marks (washboard phenomenon), and high contrast. specialty. If thick printing is used, such as FACII 394 or FACII 318, the thickness of the support pad is 1.52mm, and the depth of the relief is 1.5 to 1.8mm, the effect is also very good. The thickness of the entire printing plate is the result of the addition of the thickness of the plate material, the elastic pad, the film on the backing film, and the double-sided adhesive layer, which should be consistent with the depth of the printing plate groove of the printing machine. For machines with a groove depth of 4.5-7.0 mm, conventional corrugated board printing plates, FACII 645, FACII 550, FACII 500, FACII 470; thick FACII 394, FACII 318, and FAII 284, FAII254, and FAII 170 with elastomer liners Thin version can be used. Table 1 shows the depth of the relief when the different printing plates are printed with different contents to achieve the best printing effect. Table 1: Plate emboss depth lines and field lines and halftones Traditional plate: 2.5mm 1.5--1.8 Mm thick version (with lining): 1.5~1.8mm 1.5~1.8mm thin version: ------ 1.0mm Traditional printing plate system: Traditional printing plate refers to a Flexo printing plate with a thickness of 3.94mm to 6.35mm. Without elastic gaskets, FACII is the same. In general, the plate is fixed on a plastic slide by a double-sided tape having a thickness of 0.1-0.3 mm. The slide thickness is 0.25mm~~0.35mm. It is suspended on the plate cylinder and fixed by Matthews or Fix System. The Matthews system fixing method means that the upper end of the slide is hung on the plate cylinder, and the lower end is clamped by the keyhole. The Fix system fixes the cross bar at both ends of the slide by a special clamping device on the plate cylinder. on. The thicker version of the lining system uses thicker plates with R/bak elastic liners, which also improves screen printing quality and reduces the appearance of corrugated cardboard. FACII 3.18mm and FACII 3.94mm are two kinds of plates. FACII plate hardness 32~34 degrees Shore, designed for multi-color halftone screen printing, used for rough surface printing, with good ink transfer effect, delicate printing lines, strong reproduction, etc., can be used for corrugated board or heavy paper bag Direct printing. Its screen line number is 36 L/cm, and its adjustable range is 3-90 %. Figures 1 and 2 contrast the thick-lined printing with traditional printing. The thin-printing plates FAII 1.7, 2.54, and 2.84 mm plates belonged to this series and were made of R/bak SF and R/bak SS as elastic gaskets. The hardness of the plate is 44--46 Shore, which is harder than FACII. It is suitable for direct printing of various corrugated cardboard. Plate emboss depth 1.0mm, network cable 60l/cm, color range up to 2--95%. The application of thin plate printing has brought a new revolution in corrugated board printing. The hardness of the plate has also become the industry standard, but the final good or bad of the printing product is the joint effect of the printing plate, printing plate liner, and printing materials. the result of. Plate lining Rogers produces two types of plate liners, R/bak SF and R/bak SS. They are similar in structure and material, and they are all made of urethane foam (commonly known as granules) and are fixed on the polyester board. Only the former is 9 degrees higher than the latter, which is 20 degrees Shore. There are two methods for plate and pad lining. One is to align the padding polyester plate directly with the plate, and the padding polyester plate becomes the bottom plate of the plate. The foam material corresponds to the printing cylinder; the other, more traditional, requires the printing plate to be mounted on the film sheet, fixed by a fixing system, the gasket is directly adhered to the printing tape by a tape, and the foam material is to be contacted with the printing plate. The diaphragm is opposite. Printing Pressure and Resilience All along, flexographic printing has used a pressurizing method to speed up the transfer of ink to the base material. However, due to the phenomenon of deformation of the photo-sensitive polyester sheet under high pressure, this approach has caused dot gains. The application of thin printing technology can eliminate this distortion, because its elastic liner layer can absorb most of the pressure, thus improving the quality of corrugated printing. FAII media system advantages: FAII plate embossed angle is steep, the layout of the tone level is good, able to highly reproduce the delicate halftone dot, line outline clear, printing effect is good, greatly reducing the phenomenon of dot enlargement, expanding the scope of the palette. Not only can the tone be even when reproduced in the field, but also the tone level can be lost. In summary, the benefits of using thin-stencil technology in the direct printing of corrugated cardboard can be demonstrated by: * Increased reproducibility of delicate lines, widening of the tonal range (up to 2% for 60 l/cm screen); * Printing plate The clarity of the mid-fine fine-dotted line has been improved; * Due to the reduced surface ductility of the plate, the registration has been facilitated; * The plate-making time has been shortened; * The printing flexibility has been improved, reducing the appearance of corrugated marks (washboard); * Accelerated The entire printing speed; * Dots reduced, the scope of the color palette increased, the printing effect improved. * The outlets are cleaner and clearer. When thin printing, you should pay attention to choose the appropriate plate system. First, the entire plate thickness is determined according to the depth of the platen groove of the printing machine, which should include plate material, liners, films, tape layers, and the like. Afterwards, choosing the right backing to match the plate will result in a good print result. Table 4 lists all the matching conditions of the plate and related materials Plate Thickness Thickness Liner Thickness Slide Thickness Tape Thickness Full Thickness Hardness Traditional Plate FAC II 635 6.35mm / / 0.30mm 0.30mm 6.95mm 32- 34FACII 550 5.50mm / / 0.30mm 0.30mm 6.10mm 32-34FACII 550 5.50mm / / 0.25mm 0.25mm 6.00mm 32-34FACII 500 5.00mm / / 0.25mm 0.25mm 5.50mm 32-34FACII 470 4.70mm / / 0.30mm 0.30mm 5.30mm 32-34 thick version FACII 394 3.94mm R/bak(SF) 2.03mm 0.35mm 0.10mm 6.42mm 32-34FACII 394 3.94mm R/bak(SF) 1.52mm 0.30mm 0.10mm 5.96mm 32-34FACII 318 3.18mm R/bak(SF) 2.54mm 0.25mm 0.15mm 6.12mm 32-34 thin plate system FAII 284 2.84mm R/bak(SF/SS) 2.03mm 0.30mm 0.20mm 5.37mm 44-46FAII 284 2.84mm R /bak(SF/SS) 2.54mm 0.25mm 0.30mm 5.93mm 44-46FAII 254 2.54mm R/bak(SF/SS) 1.52mm 0.25mm 0.20mm 4.51mm 44-46FAII 254 2.54mm R/bak (SF/SS ) 2.03mm 0.30mm 0.30mm 5.17mm 44-46FAII 254 2.54mm R/bak (SF/SS) 2.54mm 0.25mm 0.25mm 5.58mm 44-46FAII 254 2.54mm R/bak (SF/SS) 3.05mm 0.25mm 0.25 Mm 6.09mm 44-46FAII 170 1.70mm R/bak(SF/SS) 1.52mm 0.25mm 0.25mm 3.7 2mm 44-46FAII 170 1.70mm R/bak (SF/SS) 2.03mm 0.25mm 0.25mm 4.23mm 44-46FAII 170 1.70mm R/bak (SF/SS) 2.54mm 0.30mm 0.10mm 4.64mm 44-46FAII 170 1.70 Mm R/bak (SF/SS) 3.05mm 0.25mm 0.10mm 5.10mm 44-46 In short, thin-printing has been around for two years and its development has been rapid, but it is still not satisfactory. One of the main reasons is that people's concept problems stick to old methods. The second reason is that due to the large plate format factor, the film is scaled when the plate format is changed to a thin plate, and related materials can only be discarded. In addition, the use of thin plate technology is not known and hinders its popularity. Thin-screen printing is the future direction of development. It provides high-quality printing methods for direct printing of corrugated cardboard.