Inkjet direct plate
In the CTPlate family, there are two relatively new members worth mentioning. One is the scanning imaging principle of a combination of a focused UV light source and a digital LCD panel exhibited by Toyo Ink Co., Ltd., which can use traditional PS plates for photocopying. UV-Setter-710HS; another Hitachi Koki company exhibited a direct plate-making system using inkjet printing imaging technology (current resolution is 600dpi).
The UV-Setter-710HS uses two UV light sources and scans the PS plate at the same time through a digital LCD panel. The scanning speed is greatly improved. The working principle of this kind of system is similar to the traditional serial dryer. The difference is that the pattern of the digital painting board is controlled by the computer digital signal, so that the digital scanning modulation of the UV light source can be realized, and the traditional PS version can be used in the original CTP application. Become reality. However, the scanning resolution of such a system is directly affected by the size of the microelectrode (electrode integration) of the liquid crystal panel. And it requires a very high scan control accuracy.
Ink-jet printing uses mechanical force to eject ink from small nozzles (typically 30-50μm in diameter) to form ink droplets. After the ink droplets reach the receptors, the ink droplets can be imprinted. Different color inks (yellow green and black) can be used to print color prints that can be obtained on the same receiving medium. The ink-jet printing ink droplet ejection status/printing status (On, Off) is completely controlled by a computer instruction and is a typical non-pact printing and plateless printing. Therefore, a digital printer operating on this principle has the characteristics of non-contact and non-printing, and can be printed on substrates of different thicknesses and different shapes (planar or curved). The ink jet printing ink droplet generation speed is generally 10-10 drops/second, which is a kind of high speed printing method. The quality of inkjet printing depends not only on the inkjet printing device and the ink properties used, ie the use of special substrates. For a long time, the low resolution of the inkjet printing system, the clogging of nozzles and the inability to print on ordinary substrates have been obstacles to the widespread use of inkjet printing technology. At present, these problems have been initially solved, and there are inkjet printing systems that can print on ordinary substrates, with resolutions of hundreds or even over 1,000 dpi. These technological advances have expanded the scope of application of inkjet printing technology, and laid the foundation for its application in digital printing.
A direct plate-making system based on ink-jet printing utilizes the principle of ink-jet printing to directly eject ink droplets onto the surface of hydrophilic substrates (such as aluminum plates with surface and anodized surfaces) to form a lipophilic printing area. (area with ink drop images) and hydrophilic non-printing areas (base plate surface without ink drop images). This system is characterized by a simple system structure, excellent operating performance, and does not require post-processing: The disadvantage is that the resolution is directly limited by the size of the ink nozzle, and it is still unable to do a high level of management. The CTPlate technology using inkjet printing is not a new invention. As early as at the German DRUPA exhibition in 1995, Polychrome exhibited a similar CTP system. The system on display at that time used a conventional inkjet printing method to print an ink drop image on a positive-printing PS plate of the system, and then performed a full UV exposure on the PS plate with ink drop images. The PS photosensitive layer on the plate with ink drop protection is not exposed to ultraviolet light, and it is still unsatisfactory, but the PS photosensitive layer without ink drop image protection becomes soluble under the action of ultraviolet light. Finally, the same printing plate as the conventional plate making method can be obtained by conventional PS plate development. However, the Solid Inkjet technology used in this year's system is directly imaged on a hydrophilic substrate, and can be printed immediately after imaging, without any post-processing. Solid ink jet technology uses a solventless ink that is solid at room temperature and liquid at the working temperature of the jet (eg, 100° C.). Such an ink comes into contact with the surface (high temperature) of the master substrate, and becomes solid due to a change in temperature, and firmly adheres to the surface of the master substrate, becoming an image area of ​​the printing plate. The current issue is how to increase the resolution of this approach to meet the needs of commercial printing. It should be said that this imaging method without any post-processing is more suitable for CTPress applications.
Purple Laser CTP Technology
The violet laser CTP technology consists of a violet laser CTP platemaking system and a CTP plate that can be used for violet lasers. In the case of a platemaking system, the core is a laser diode capable of generating a violet laser of 400-410 nm.
People love violet laser for the following reasons:
Economical
Because its relatively short wavelength (around 405nm) and the current universal 830nm wavelength make it easier to avoid light divergence, long-distance transmission can be realized with a compact structure, which means that inexpensive semiconductor lasers can be used as internal drums. The CTP plate making machine reduces the manufacturing cost of the CTP plate making machine, conveniently corresponds to the output of plates of different sizes and different weights. In addition, since the rotating mirror can be kept very small and light, the high speed scanning can be realized. , Improve the production efficiency of the CTP into the platemaking machine.
2. Near to bright room operation
3. The design of the plate becomes easy
The current situation is that the power of UV diodes is relatively low, generally 5mW, so the sensitivity of the plates is required to be higher, that is, ≤20μJ/cm2. Currently, only the silver salt diffusion plate and the photosensitivity giant version are applicable.
The real potential of UV lasers is the appearance of diodes with larger power (eg, 30-50 mW) and wavelengths moving in the short-wave direction (eg, 350-380 nm). That will threaten all current forms of CTP technology, and of course it will also be the biggest opportunity for media producers.
In order to understand the requirements of the sensitivity of the laser to the plate material, the sensitivity of the commonly used photosensitive materials is listed as follows:
1 silver halide film μJ/cm2
2 silver edition (Silver salt diffusion, composite version) μJ/cm2
*3 Purple Laser Edition LV-2 (Mitsubishi) 10 μJ/cm2
*4 Purple Laser Edition (Fuji) 60μJ/cm2
5 high sensitivity photosensitive resin 100-200μJ/cm2
6 thermal plate 150mj/cm2
7 regular PS version 200-400mj/cm2
* Asterisk is the purple laser CTP plate that was introduced at the Drupa exhibition.
CTcP, UV-LD lasers have been successfully studied in foreign countries so that the conventional PS plate can also be used as a CTP plate. This will greatly ease the difficulty of direct plate development and development, and will greatly promote the popularization of direct plate-making technology. In the early 1990s, a more mature violet laser source emerged. Not only the laser energy was relatively large, reaching several tens of μJ/cm2, but also the lifetime of the light source was relatively large, reaching 2,000 hours or even longer. Therefore, it appeared to be strong once it appeared. Development, and even at the 2000 Drupa exhibition in Germany, almost all CTP systems are equipped with a violet laser light source. With the maturation of violet laser technology, a newer CTP technology has emerged. Many people in the industry call it CTcP. It uses CTP technology to expose directly on conventional PS plates.
Features:
1. Ultraviolet light source, with a wavelength of 360-450nm; its spectrum is fully applicable to conventional PS plate, can use conventional negative, positive PS plate
2. No need to adjust the printing platemaking process
3. Smooth transition from simulated prepress system to current CTP prepress network
4. With automatic plate processing system
5. It meets almost all printing tasks, whether it is newspapers, books or high-quality color printing.
Conventional UV-sensitive printing plates are cheap, after many years of verification has been very reliable, a high printing, high resistance to printing, compared with the use of expensive, newly developed laser-exposed plate, UV-Setter means prepress There is no need to change the system and media processing. Everything can be left as it is: high quality, low cost, and unchanged programs.
Most of the plates used in printing on the market can be exposed by UV-Setter. According to the characteristics of the media, it is best to use negative editions, which only need to be partially exposed. Because negative editions have only 50% of the image area on average, this saves valuable exposure time.
The New Development of Computer Direct Plate Making CTcP
For the first time in the world printing exhibition, the conventional PS version of the UV light source CTP system is at the Drupa 2000 exhibition, referred to as CTcP. It has two forms, one of which was first introduced by BasysPrint. Its working principle is as large as: ordinary UV light source, after the lens will be scattered light into parallel light, projected to the computer integrated chip DMD (Digital Micromirror Device), and DMD is controlled by computer digital image information, will change the image information Converted to reflective dots, image information is thus imaged on the plate. The core component of this CTP system is a computer-integrated chip (DMD) of about 4 x 3 in size from Texas Industrial Co., Ltd., USA. According to Basysprint, the technology should be used in a computer-to-plate system, which is the company's first. According to reports, at present, the dots formed by this plate-making method are square dots, and the points on the map are very neat.
2. Fiber exposure system
The world's first optical fiber direct printing system is represented by: Durop-Eskofot (Dr.), a computer-to-plate system that can be imaged on the ordinary PS plate and displayed on Drupa 2000 as a prototype. The system is a plane scan type, light source 2KW mercury lamp. It can expose and process 30-50 pages per hour. It can be negative or positive. The prepared version has been dried and punched, and can be directly printed on the machine. The principle is very similar to the scanner.
The Dicon system directs UV light from the UV lamp through a fiber optic to a series of LSAs, which combine to form an exposure grating that covers the maximum width of the media. Each shutter provides a 20um spot and is arranged with a 1um of light to display a light gate. The resolution of Dicon platemaking machine has 1270dpi and 2540dpi for user's choice. The plate size can be from 510mm x 400mm to 1125mm x 825mm, and the plate thickness is 0.15-0.4mm.
Baoluo Telford will launch semi-automatic and fully automatic models when the Dicon system is officially put on the market to meet the needs of different users. The Dicon system can operate in the bright room. After the printing plate is exposed, the built-in punching unit can punch holes on the plate according to the customer's needs and automatically send the plate to the line processor. The data that drives the Dicon platesetter comes from ProBio's NewAge RIP, and the digital proofing material can also be output on Dicon.
CTPP (Computer to Polyester Plate)
This type of media is based on a polyester film (0.1-0.4mm) in structure, principle, exposure method, and similar silver plate. Compared with general CTP plate, it has lower resistance (1-20000) and lower resolution (5 -95%), but its stability is good and its price is relatively cheap. Especially after a special plate material output machine (or a normal laser imagesetter) can be used, the plate making process becomes very fast (from the original 30 minutes to 8 minutes). Because of the use of printing presses, it was able to make great use of the printing force. Therefore, it was said that such printing plates will have a promising future in the printing field. At present, Japan's Mitsubishi Paper and Agfa have the largest output in the world.
FD-FB exhibited by Japan's Mitsubishi Paper at the Drupa exhibition can now be used under the environment of the company's CTP technology solution.