Screening: two sounds from the field of web printing

Screening: two sounds from the field of web printing

We are a big printing company in Shenzhen China . We offer all book publications, hardcover book printing, papercover book printing, hardcover notebook, sprial book printing, saddle stiching book printing, booklet printing,packaging box, calendars, all kinds of PVC, product brochures, notes, Children's book, stickers, all kinds of special paper color printing products, game cardand so on.

For more information please visit 

http://www.joyful-printing.com.   ENG only    

http://www.joyful-printing.net 

http://www.joyful-printing.org

email: info@joyful-printing.net

Screening

For rotary printing, with the use of non-traditional screening techniques, the problem of ink accumulation often occurs. Mr. John Lind reminded us: “Successful use of the new screening technology depends on suitable inks, paper, rubber lining, and arrangement of printing rollers, etc. The ink stacking often occurs in high light areas – Many dampening solutions adhere to these areas, and if not cleaned frequently, the blanket will be damaged."

A seminar sponsored by M-Real Paper was held in Stuttgart, Germany, where nine rotary printers came together to discuss various issues in random screening. The meeting came to an astonishing conclusion: all members refused to use random screening techniques.

The most complaints from these printing companies are dot gain, compensation curves, and complex adjustments in the printing process. They believe that the use of FM screening will make the ink film thinner, which will lead to more serious blanket filth, which means frequent cleaning of the blanket.

In order to be able to achieve a full reproduction in the dark area, it often causes serious ink accumulation on the blanket. Printing operators often do not pay attention to this problem because it does not appear to be noticeable on the printed sheet. Therefore, the ink will form an ink on the blanket, leaving a slight crack when cleaning the blanket. Soon the crack on the blanket will get bigger until the blanket is replaced.

These issues are sometimes reflected in ink manufacturers. The problem of stacking ink is caused by the fact that the dots are too small, and on the other hand, the ink film used in the random screening process itself is very thin, and the dampening solution is also relatively small. As a result, the printer has no more room or choice to make adjustments on the press.

It is recommended that when this type of problem is encountered, either replace the ink or reduce the dampening solution concentration, so that the operator can use more dampening solution to reduce the problem of stacking.

We don't specialize in the production of inks for random screening, but we know what kind of ink is suitable for what is not suitable, hard ink is not suitable for random screening, because the random screen printing ink is so thin that it will There is a phenomenon of water washing, which causes the ink to be unbalanced. A good applicability ink has a strong water repellency.

When moving from AM screening to FM screening, some companies have to create different dot gain compensation curves and use inks with different viscosity values.

   Compared to web printing, our printers prefer to use FM screening in sheetfed printing. Sheet-fed printing has a short preparation time and a small color change. Registration accuracy is easy to guarantee and it is difficult to see visible white dot patterns. For sheetfed printing, especially for people's face printing, we are able to print a subtle, high-gloss, dark-tone, smooth transition skin tone effect. This is not an easy task for web printing. Our staff do not like FM screening. This is because of a stacking fault on the web press.

The use of FM screening also reduces the life of the plate. Using Creo's Staccato technology on a rotary press, the plate's print durability is reduced, which increases our plate usage. We found that the FM technology is not suitable for the printing of high-speed lines in rotary printing. The number of network cables is higher than 200 lpi. ”

We have some older rotary printing equipment, which also produces detailed and detailed prints for us. We print some furniture leaflets. It is very important for our customers to print bright and clean images. We don't have any problems with moiré stripe here, and the registration effect is guaranteed, which is very important for wide web printing. ”

Suffoletto, a researcher at RIT School, believes that the best reason for new technology to be accepted is ease of use. Printing companies want to be plug-and-play so convenient, they don't want to do any expensive and time-consuming improvements, research and testing. They also really don't want to change existing raw materials or supply channels. Therefore, when the manufacturer says that it is necessary to change the fountain solution, blanket or ink, they want to block their ears. ”

Random screening has its value, but what I need is the advantage that allows me to maintain 95% of the time without downtime, to be able to compete with random screening, and to do so without making too much change. If you want to use random screening technology, you will be confused about your prepress and printing departments.

Some people think that the use of FM screening technology does not require additional process control. If the printing company uses the conventional process control method, the printing machine is also in normal working condition, then they can use random screening technology. Many of our customers apply the new screening technology directly without any changes. If you go through the yellow pages, you will see that 80% of the factories in North America are printed by random screening, Wal-Mart (Wal- The same is true of most poster flyers from Mart) and Home Depot Home Sales. When printing such prints, the press requires very little control of the printing process. Any sheetfed printer needs to pay more for process control than a company that uses FM screening technology. It is not difficult to use FM screening.

Printers can't change colors during the printing process, and you may have a 40-60% chance to change colors compared to traditional screening. Using the random screening technology on the press, we can increase the ink density to 20% without seeing any changes.