The core technology of CTP

There are already some printing companies that regard CTP as an indispensable product, but more than 75% of them still think it is still too early and the opportunity is not yet mature. Perhaps only when the first wave of investment in the CTP comes and all the advantages of the CTP technology are revealed, it is possible to have sufficient evidence to convince those who take a wait-and-see attitude.

Another reason why companies are not determined to invest in CTP may be the lack of understanding of various existing CTP solutions, and it is impossible to face so many choices. IPEX offers us an opportunity to truly understand the potential of various CTP products and discover their strengths and weaknesses.

This article gives a brief introduction to the CTP technology exhibited at IPEX and hopes to help companies that want to invest in CTP.

There are currently three types of core technologies: variants of the inner drum, outer drum, and X/Y scanner principles (platform type). At this time, the plate is flat, but when the imaging head scans on the plate, The plate moves in the direction of the winch. Agfa's Palladio and Screen's PlateRite are two rare CTP platesetters that use platform technology.

The platform technology is a bit like a drumless device without a drum, and has many advantages, especially the cost advantage. Because it is a platform design, the storage or imaging of the printing plate is performed in the horizontal direction, which is simple and reliable. Accurate mechanical transport allows the imaging platform to run smoothly and the imaging is more accurate.

The plate pack of the inner drum device is fixed on the inner side of the drum, and the plate is exposed by the movement of the laser beam. This is one of the most widely used technologies, and the upwardly moving polyester plate mostly uses the inner drum type. equipment. In terms of quality, because the distance between the imaging plate and the mirror is constant, the laser spot size and the focusing distance can be ensured, so the quality is good, the optical system is simple, and the failure rate is low.

The company that actively promotes and develops this technology is Biodet, who introduced a new version of the PlateDriver, in which the rotating mirror rotates at more than 80,000 revolutions per minute. In addition PlateDriver also uses a completely different way of moving, so that the imaging light source outside the drum, through the optical fiber to the light beam to the mirror, very easy to maintain.

The company exhibiting CTP platesetters using internal drum technology at the show is AB Dick. Its rotating speed of the rotating mirror is between 30,000 and 50,000 revolutions per minute. AB Dick Company and ScanView Company jointly developed a series of internal drum equipment, mainly using polyester plates and metal plates.

Although the polyester version is not yet widely used, it is indeed a printing plate used in the production of high-quality products and short-run jobs. With the polyester version, any four-color B3 format printer can reproduce very beautiful colors. Some companies represented by Apex Digital Graphics in the UK have strongly called for the development of a polyester version of the CTP system, which can achieve the perfect combination of performance and cost.

There are several options in the inner drum device. Continuous lasers are usually used in the imaging system of inner drum equipment, because the light beam is relatively easy to focus and does not lose energy even if it travels a short distance. The narrower the wavelength band of the laser spectrum, the greater the energy transmitted, so equipment manufacturers are usually happy to choose an argon ion laser with a wavelength of 488 nm or a 532 nm Yag laser.

However, the recent development of violet laser diodes has threatened market stability because diodes can be easily adjusted (on or off), and diodes are extremely inexpensive and have a long service life.

Agfa's flagship Galileo series is developed by Agfa and has the highest level of internal drum technology, namely, models that run violet laser diode imaging systems, and models that use the 532 nm Yag laser imaging system.

Heidelberg is always leading the trend of technology, and recently they have also developed the Prosetter, a violet laser platesetter with a resolution of up to 3386 dpi, a very small footprint, and can be used as a safety light for all violet laser equipment. Under the operation.

In addition, Heidelberg still supports thermal technology, and Jim Todd, company sales director, said: “The future trend is thermal technology and blue-violet laser technology, although the restrictions on consumables have so far hindered the development of violet laser technology, but with the With the increasing number of edition choices, the application of it will grow significantly in the coming period of time."

Fujifilm's latest B1-format Luxel V9600 requires a 30mW laser diode with the ability to output more than 30 plates in one hour, using Fujifilm's own printing plate, exposed to a violet laser. Luscher's internal drum platesetter is also worth a look.

One of the biggest drawbacks of inner drum technology is that it is not suitable for thermal plates, and outer drum technology is the ideal technology for exposure on thermal plates. This is because the thermal plate causes changes in the emulsion layer under the influence of heat rather than light intensity. The light beam generated by the diode is longer than the blue-violet laser light, and is rectangular in shape, and therefore spreads even over a relatively short distance. The attractiveness of this technology is very large, and Creo has applied this technology on its own devices.

Creo confidently believes that their thermal solution is the first product with FM screen capability. Hexachrome (Pantone's six-color separation technology) currently using FM technology and other forms of color separation technology all advocate the use of Creo's CTP solution.

The advantages and disadvantages of the external drum technology are almost half of each other. In the external drum technology, the Chinese printing plate rotates continuously with the drum, and the structure is more complicated than the internal drum technology. Each time the media is replaced, the drum needs to be balanced, and the upper and lower versions are also very ineffective. Convenience.

In terms of drum technology, Screen UK is a Creo company’s competitor. Kodak Polychrome Graphics also uses external drum technology, but like Agfa, the company focuses mainly on sales of plates. They also have confidence in the future of thermal plates.

Screen UK once tried to develop both internal and external drum products at the same time, but now it has completely focused on the development of external drum technology. The company's product structure is very simple and enjoys a high reputation for reliability. The company uses an automatic balance hammer to balance the drums and it works well. Like Creo, they also believe that the plates in the drum technology are relatively dust-free, because the plates are always moving, and they think the rotating technology of the rotating mirror is more complicated.

But for customers, their buying decision is very practical. The replacement cost of the thermal diode array is very high. At the same time, the complexity of the 260-diode controller is also high. Therefore, it is hoped that manufacturers will consider increasing the diode's capacity and speeding up the rotation speed of the drum in the future development process instead of increasing the The size of the diode array. Because the distance between the diode array and the plate is very close, little energy is wasted.

Many customers have a preconceived feeling when deciding which product to purchase. This must be done with caution because the first time you see is not necessarily the best product. Before making a decision, it is necessary to consider the issue of workflow. It is an integral part of the CTP solution. Every manufacturer of CTP equipment will present integrated solutions. So how comfortable is it with the supplier? And how much the supplier knows about your business situation is more important than making a choice for a specific CTP system.

In PrintCity at the show, MAN Roland and PPS jointly demonstrated the integrated workflow solution. At the same time, there were also independent vendors of other vendors participating in the exhibition. Heidelberg believes the most important features are the Prinance, JDF and CIP4 concepts. The reason for emphasizing this is obvious. In the coming years, these concepts will reliably provide services and support for all systems, whether they are drums or other structural systems. For the foreseeable days, there will be CTP systems that support silver salt, violet, polyester, or thermal plates.

Source: Digital Printing