Analysis of Selection Examples of Corrugated Cardboard Flexible Plates

The quality of flexographic printing of corrugated cartons is constantly being improved. In the future, some products on offset and gravure will gradually shift to flexo printing. The main reason is due to the quality of inks, plates, anilox rolls and printed materials. Have improved. Of course, this must be based on the premise of a mature product with excellent quality and reliable quality. We will use the plate as an example to explain.

How can I tell the difference between different plates in the printing of corrugated boxes?

The accuracy of plate typesetting in printing will directly affect the quality of printing after printing. Therefore, we must also control this aspect and make the color printing typesetting convenient and accurate. If the film output is required to register the crosshairs, this crosshair is the key to printing plate alignment. Because we use different cross-color printing plates to align the positions of the printing plate, but the crosshairs are not enough. Conversely, the transparency of the media is very important, because only the transparent media can clearly see the following crosshairs, and DuPont's DRC is able to display accurate sets of colors when it is transparent because of the light pink. Accuracy. In the same way, the dark yellow KY, dark blue, and dark green JET will certainly spend a lot of time on the trapping, and the accuracy will not be guaranteed, which will affect the accuracy of the final print.

The surface viscosity of the finished plate must be non-stick when printing. If the surface of the plate remains sticky, it will stick to the garbage and dander on the surface of the platen, so that the small area will not be inked. , resulting in print leaks. Because DuPont DRC's plate material is very good in terms of tackiness, the finished plate has almost no stickiness after drying, and it is smooth and translucent after UVC detacking. After KY and JET have finished printing, the chemical reaction between the resin and the solvent is very severe. The detackification time of the plate is no longer effective for 20 minutes. The surface is still very sticky. Therefore, the two plates are printed. At the same time, trash and dander on the cardboard surface are often stuck to the printing plate, resulting in print leakage. During printing, the number of times that the operator stops printing and erasing the printing plate will be far greater than that of DuPont's DRC, and they are all intended to clean up the rubbish and dander that stick on the surface of the plate. This will seriously affect the printing quality and the machine's production efficiency.

The JET version appeared earlier in the Asia-Pacific region, especially in Japan, and in China it can be traced back to two years or even earlier. In the last 1-2 years, the low-end (JET version, KY version) and high-end (DuPont version) have become the two main choices in certain specific areas, such as price as the primary consideration or short-term. The long list we know is more than 500,000. DuPont Edition can easily reach 1 million impressions:

Strictly speaking, in Shanghai, they regard shortcomings of less than 200,000. The JET version is capable of printing 100,000-200,000 yen, so the JET version of the short-listing market has been cheaply penetrated. As far as the 112 and 155 versions are concerned, the plate making capability of the JET plate is similar to that of the old DRC plate, such as 0.2 mm lines and 0.4 mm independent dots. It can easily do 3% of the points 601pi. The depth of the graphic is quite good. Smooth film can also be used for plate making. The plate making time does not exceed 2 hours (back exposure = 1-2 minutes, main exposure = 6-10 minutes, plate wash = 5-8 minutes, drying = 50-60 minutes, detackification / post-treatment = 10 minutes.)

Although the JET version is extremely cheap and the plate-making performance is acceptable, its print adaptability is almost the same as that of the KY, and it is not comparable to the DuPont version with good quality. In particular, the flatness and hardness of its layout will become the killer of printed materials, as many customers report that the surface of the JET version has pits. When printing, there will be a leak, and in order to overcome the leak, it will increase the pressure, because the version The material is too hard and put

Corrugated flattened and damaged, thereby affecting the corrugated carton's ability to resist pressure.

KY and JET's plate base and the resin are not very well polymerized, and it is easy to tear the substrate. It does not really protect the plate. If it is accidentally folded, it will crease the plate. Such a version will be torn wrong when making a plate, so that the version is scrapped. KY resin will flow out during the storage process, destroy the flatness of the plate, so that the thickness of the finished plate appears, resulting in poor printing, this phenomenon is particularly prominent and frequent in the summer when the temperature is high.

In addition, the stability of KY and JET plates is not good, and the plate hardness will increase with the increase of the number of printing, resulting in worse and worse ink transferability, such as printing leakage, ink layer unevenness, corrugated appearance, etc. . In addition, the transferability of ink is not as good as that of DuPont DRC, because DRC inherits the excellent ink transfer properties of TDR, making it easier and more convenient to apply ink during printing. DRC is a product developed for direct printing of corrugated cardboard like TDR plates. The main difference between it and TDR is that its hard bottom is bigger than TDR. Its hard bottom is about 37. Its purpose is to meet the demand of some users for some hard plates.

In addition, the color of the DRC is much lighter than that of the TDR, and the transparency is high, allowing the printer to follow the bottom line. Another feature of DRC is that the exposure time is shorter than TDR, mainly to meet the requirements of low energy lamps (most domestic lamps) used by some domestic manufacturers.

DRC has a large depth of text, high resolution, and clear, delicate prints, making it particularly suitable for the printing of Chinese characters.

Attach DuPont 155DRC media test parameters for reference by the plate makers:

1, test conditions

Dupont 155DRC
Plate Making Machine DUPONT1002
Main exposure light source: UVA 100W Light intensity: 18.5---18.6mw/cm2
Detachable light tube: UVC 60W Light intensity: 10.5---10.6mw/cm2
After exposure light source: UVA 100W Light intensity: 18.5---18.6mw/cm2
Washing solvent: FlexoSol

2, back exposure test

Exposure time 25s 30s 35s 40s 45s 50s 55s 60s 65s
Base thickness 2.01mm 2.11mm 2.22mm 2.42mm 2.59mm 2.71mm 2.9mm 3.02mm 3.15mm
Washing time: 550 seconds, drying 3h, total thickness 3.94mm

3, the main exposure test

Film was selected by Jiuheng publicity film, the minimum and maximum outlets were 2% & 95% @ 50lpi, the smallest yin and yang independent outlet 0.5Pt, the smallest individual YinPing independent line 0.5Pt, the smallest Yin Yang 5pt.
Back exposure time 25 s, base 2.00 mm, wash time 550 s, drying for 3 hrs, defoam 3 min, post exposure 6 min. The hardness of the plate is 37 degrees.

Exposure time - description of platemaking situation

The thinnest lines of 3min are slightly bent, and the independent points of 1Pt and below are washed away. 2% of the dots are washed away, and 3% of the dots are slightly missing. The sharpness is about 60--70 degrees, and the shade is darker. Evaluation: The picture is slightly incomplete, the exposure time is slightly shorter and the sharpness is appropriate.

6min 3% of the outlets are clear and tidy, and 2% of the outlets are slightly incomplete. The sharpness is about 60--70 degrees, and the shade is darker. Assessment: The picture is complete, the exposure time is appropriate, the sharpness is appropriate, and the stability of text, lines, and dots is good.

8min 2% of the network is clear and neat, the line sharpness is about 60--70 degrees, and the shade is darker. Assessment: The picture is complete, the exposure time is appropriate, the sharpness is appropriate, and the stability of text, lines, and dots is good.

14min 2% of the network is clear and neat, the line sharpness is about 60--70 degrees, and the shade is darker. Assessment: The picture is complete, the exposure time is appropriate, the sharpness is appropriate, and the stability of text, lines, and dots is good.

6. Comprehensive assessment:

The plate has a large exposure latitude (6-14 minutes). After washing, the resin is not sticky and has strong toughness and is not easily torn. Sharpness is better and it is good for printing. The hardness after the plate making is 37 Shore, the printing is thick in the field, the dots are clear, and the washing board phenomenon is not easy to appear, which is especially suitable for the printing of corrugated boxes.

Every process in the printing field is the key, including scanning, creativity, production, color separation and other work that will be reflected in the final printed matter, and it is more important to carry out careful media. Material selection, strict process management, can guarantee the smooth progress of the final printing.