Analysis of Pad Printing Technology

3. Fixtures are handy

One of the important reasons why the special printing industry is special is that the product shapes it involves have never been unified like paper, so almost every product has to be made with a special fixture. The optical disc has been standardized, and the shape of the most popular 120 mm optical disc on the market is very fixed. It is very simple to make such a fixture, and it is not difficult to make a special optical disc fixture. Although fixture production is simple, sometimes there is no commonality and printing can be difficult. Because of the shrinkage rate of plastic products, the final product's external dimensions are actually different. If the error is large, the production of the fixture will be very tricky. It may be difficult for you to produce it, and it cannot be produced on the printing press.

Although most CD-ROM manufacturers provide highly standardized CDs, you must be good at measuring these products. If you exceed your standards, you must try to solve them. Otherwise, over-printing problems will always trouble you.

4. Resin plate outlets are good

If the disc requires a higher print quality, it is best to use a pad printing resin. This is a polymer version, with a mature platemaking technology. The resolution and resolution of the printing plate is much higher than that of the steel plate. It does not require an etching process, so there is no one that causes headaches due to corrosion. Line defects and inconsistencies. Pad printing resin plates are easier to make into a plate structure, which is undoubtedly a good thing for those who use landscapes and characters as the theme of the CD picture.

The application of the resin plate is not much different from that of the steel plate. In the conventional pad printing machine, the ceramic magnetic steel plate is added, and the resin plate will be firmly sucked on the surface of the steel plate. The others are basically the same as the steel plate. In order to improve the resistance of the resin plate, the steel blade is replaced with a squeegee with a hardness of 85 degrees Shore. However, the resistance of the resin version is not high, and printing large-volume discs may require more plates. The application of the resin version is also limited to those companies whose manufacturing standards are in place. Otherwise, the printing process is likely to be in great trouble. If the ink is not clean The deinking of the plate is not very good.

5. The disc pad printer is stable. reliable

Two-color and five-color optical disc printers have already entered the market, and customers are still very much recognized. Two-color disc printing machine is mainly used for printing spot color blocks and transition color disc products. There are 57% of discs on the market with only two colors, and the color is only a gradual effect. This type of printing machine is suitable. There are 43% of optical discs that need fine landscape paintings or figure paintings. They must be printed on a five-color disc pad printer. They include white underlays and four-color overlays.

The current optical disc printers are all composed of a disc transport device, a disc printing device, and an automatic control system. The optical disc transport device can accumulate the discs on the conveyor belt into 50 stacks at a time, and is strung by a stainless steel column with a diameter of 14 mm. When the sensor at the top of the column detects the presence of the disc, the manipulator sucks the disc onto a special fixture on the rotary table. The table rotates into the printing position. The sensor issues a command to the control circuit and the plastic head presses down to start printing. Throughout the printing process, the disc is always in one position and overprinting is accurate.

The multi-color printing machine for CDs has two major features compared to traditional multi-color printing machines. One is that the conveying process of the product is fully automated, unlike the screen printing, which requires manual picking and placing, and the other disc is the next color program. Large disc tables, which rely on precision anglers, are much more efficient and precise than traditional tables.

As can be seen from the above description, these pad printing machines use solvent-based pad printing inks. Due to the relatively fast drying speed, practically no problem arises on a multi-color pad printing machine.

Fourth, the CD UV printing process

Multi-color screen printers using solvent-based inks have not been successfully accepted by the market. We cannot tolerate a high-speed machine that always stops to wipe the blocked mesh. This creates many potential problems: Production The efficiency is seriously affected, the color of the disc is not uniform, and a large amount of waste products appear. This is the reason why it must use UV ink, and the use of UV ink will greatly complicate the structure of the machine.

The successful use of solvent-based inks in pad printing does not mean that we have not paid attention to the progress of UV technology. In fact, the development of UV pad printing technology has been continuously carried out both theoretically and practically. UV pad printing inks will make the print coating better quality, more wear resistant, and higher gloss.

CD UV printing process shown in Figure 1.

The above pad printing process has been proved to be feasible by practice, but it can be seen that it does not protect the picture layer by UV varnish coating like offset printing. This is the current status of pad printing. Many manufacturers finally use a monochrome screen printer to apply a layer of UV varnish to compensate for this defect.

It is not particularly troublesome to install a UV curing device on a multi-color pad printing machine because multi-color screen printing machines have had very successful experience. The key is that we must look for specialized UV pad printing inks. If the UV printing technology of optical discs still needs further study, we must find a more mature and stable optical disc UV pad printing ink.

In February 2004, MARABU officially launched its TPUV series of UV pad printing inks. Although this ink did not claim to be targeted for PC discs, preliminary tests proved that the effect was satisfactory.

Optical disk printing technology is a relatively young technology. Therefore, it must learn from the features of other mature printing technologies in order to continue to mature. In the 21st century, the development of engineering technology has a wide range of significance in terms of integration and deepening, and printing technology is no exception. In terms of integration, there has been a very close blood relationship printing, screen printing. The cooperation of offset printing and the formation of more mature printing technologies deserves attention; in the aspect of deepening, any printing technology continues to draw on the blood of high and new technology, and it is moving toward the direction of being recognized by operators, environmentalists and business managers.

(Text / Bai Songfang Dongguan Tiandi Printing Technology Co., Ltd.)

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