Random talk on CD pad printing technology in the m

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Random talk on CD pad printing technology in silk printing and offset printing (Part 2)

is the process easy to control

the social demand for CD-ROM products is very large, and printing is one of the essential processes, so it is very important to implement a stable printing process. Is there an easy to control process in CD-ROM printing? The answer is yes

1. The patented PCU core printing ink is very mature between the disc transfer plates.

the disc transfer printing ink has developed into a special series, which not only has the adhesion to PC materials, but also begins to pay attention to some characteristics of the disc. CD pad printing ink requires certain temperature resistance and friction resistance to resist the negative effects of laser reading and writing process; Discs are also often exposed to sweat, requiring better oil resistance; For the background ink, in order to improve the reflectivity of the CD when reading and writing, the hiding power should be high. These are no longer difficult things. The CD pad printing inks manufactured by major ink manufacturers can basically meet these requirements

Bo mule, vice chairman of BASF executive board and chief technology officer, said that some discs with low requirements may be mainly represented by simple color blocks, but discs with hierarchical requirements need four primary color disc ink. These are very simple things for other printing methods, but in the pad printing industry, some people are very random about choosing four-color ink, so it is impossible to print an ideal CD. Most of the employees in the pad printing industry may have no professional printing knowledge and lack understanding of why they have to choose four-color inks

2. The pad printing adhesive head is a relatively independent pressure device, which moves back and forth on the printing plate and the substrate to transfer ink. The change of its size is generally not affected by the machine structure. A machine can often be assembled with several rubber heads to print products with different printing areas, which greatly enhances the adaptability of products. For CD printing, the shape of the glue head is basically the same. We can all make a circular glue head with a hole in the center. For some special-shaped discs and business card discs, we can use rectangular rubber heads instead

the hardness of the rubber head is another indicator. As a result of the flat pressing of the rubber head, the pressure in the central area of the rubber head is significantly greater than that around it. If the approximate Hooke's law is used to explain it, that is, the compression of the edge is relatively small, and the compression of the central area is relatively large. The harder the rubber head is, the greater the pressure will be required for the printing of the edge area. Of course, if the rubber head is very soft, although printing is easy to achieve, for a relatively fine CD, there will be a problem of unclear graphics and text. This can be solved by changing the curvature of the bottom of the rubber head. If printing fine images and eye-catching images, the hardness of the glue head should be larger, but the curvature of the bottom should be smaller or the zero position often changes; On the contrary, for rough printed discs, the hardness of the rubber head can be appropriately smaller, but the curvature of the bottom is required to be larger

3. Fixture making handy

one important reason why the special printing industry is special is that the shape of the products it involves has never been as standard and unified as paper, so almost every product needs to make a special fixture. The optical disc has been standardized. Now the shape of the most common 120mm optical disc in the market is very fixed. Making such a fixture is very simple, and making a special-shaped optical disc fixture is not difficult

although fixture production is simple, sometimes it is difficult to find commonalities, and printing is difficult to continue. Due to the shrinkage of plastic products, the overall dimensions of the final products are actually different. If the error is large, making fixtures will be very difficult. Maybe you worked hard to make them, but you can't produce them on the printing machine

although most disc manufacturers provide highly standardized discs, you must be good at measuring these products. Once they exceed the standard, you must find a way to solve it, otherwise the problem of inaccurate overprint will always trouble you

4. Resin version has good point reducibility

if the CD requires high printing quality, it is best to choose pad printing resin version. This is a polymer plate with mature plate making technology. The resolution and clarity of the printing plate are much higher than that of the steel plate. It does not need corrosion procedures, so there are no line defects and differences in depth caused by corrosion. For a long time, new wood plastic composite materials have not been effectively industrialized and commercialized. Pad printing resin plates are easier to be made into point structure plates, which is undoubtedly a good thing for those CD-ROM graphics and texts with the theme of scenery and people

the application of resin plate is not much different from that of steel plate. If ceramic magnetic steel plate is installed on the traditional pad printing machine, the resin plate will be firmly absorbed on the surface of steel plate, and others are basically the same as steel plate. In order to improve the printing resistance of the resin version, it is also good to replace the steel blade with a rubber scraper with a hardness of shore 85 degrees. However, the printing resistance of the resin version is not high, and more printing plates may need to be prepared for printing large quantities of CDs. The application of resin version is also limited to those enterprises with relatively high manufacturing level, otherwise, the printing process is likely to have great trouble. Such as the ink scraping is not clean, the deinking of the printing plate is not very good, etc

5. CD pad printer is stable and reliable

the two-color and five color CD pad printer has already entered the market, and customers still recognize it. The two-color disc pad printer mainly prints spot color blocks and transition color disc products. 57% of the discs on the market have only two colors, and the color is only a little gradual change. This kind of printer is very suitable. Another 43% of the discs need to be decorated with fine landscape paintings or figure paintings, which must be printed by a five color disc pad printer, which includes white backing and four primary colors overprint

the current CD pad printer is composed of CD conveyor, CD printer and automatic control system. The optical disc conveyor can accumulate the optical discs on the conveyor belt into 50 at a time and stack them, which are strung by a stainless steel column with a diameter of 14mm. When the sensor at the top of the column detects the existence of the disc, the manipulator will suck the disc and place it on the special fixture on the rotating workbench. The workbench rotates into the printing position. The sensor sends a command to the control circuit, and the rubber head is pressed down to start printing. In the whole printing process, the disc is always kept in one position, and the overprint is very accurate

compared with the traditional multi-color pad printing machine, the CD multi-color pad printing machine has two major characteristics: one is that the product conveying process is fully automated, which does not require manual picking and placing like printing; The other is that the disc enters the next color program, which is a large disc workbench controlled by a precision angle divider, which is much more efficient and accurate than the traditional workbench

it can be seen from the above description that these pad printing machines use solvent based pad printing inks. Due to their fast drying speed, there will not be much problem on multicolor pad printing machines

CD UV pad printing process

the multi-color printing machine using solvent based ink has not been successfully accepted by the market. We can't tolerate a high-speed machine that always stops to wipe the blocked holes, which will cause many potential problems: the production efficiency is seriously affected, the color of the CD is not unified, and there are a lot of waste products. This is the reason why it must use UV ink, which will greatly complicate the structure of the machine

the successful application of solvent based inks in CD 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 carried out continuously in theory and practice. UV pad printing ink will make the printing coating better in quality, wear resistance and gloss

optical disc UV pad printing process:

optical disc transmission - optical disc superposition - optical disc detection - pad printing white background - UV curing - four color pad printing - UV curing - optical disc finished product

the above pad printing process has been proved to be feasible in practice, but it can be seen that it does not carry out UV varnish coating to protect the image and text layer like offset printing, which is the current situation of pad printing. Many manufacturers finally use a monochrome printer to coat a layer of UV varnish to make up for this defect

it is not particularly troublesome to install a UV curing device on the multi-color pad printer, because the multi-color printer has a very successful experience, and the key is that we must find a special UV pad printing ink. If the CD-ROM UV pad printing technology needs further research, it is that we must find a more mature and stable CD-ROM UV pad printing ink

CD pad printing technology is a relatively young technology. Therefore, it must learn from some characteristics of other mature printing technologies in order to continue to mature. In the 21st century, the development of engineering technology is of great significance in both integration and deepening, and printing technology is no exception. In terms of integration, pad printing, printing and offset printing, which are closely related, should be paid attention to to to form a more mature printing technology; In terms of deepening, any printing technology is constantly drawing on the blood of high and new technology, and moving towards the direction of being fully recognized by operators, environmental protectors and enterprise managers

source: Chenyi

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