From DTP to CTP (top)

The abbreviation of Desktop Publishing System is DTP, and the English name is De Publish. The desktop publishing system integrates text photocopying, image color separation, graphic editing and synthesis, creative design, and output of color pictures or color separation films. It is unmatched by past photoengraving, electric sheet making, and even full-page imposition systems. It brings bright prospects for printing, publishing, packaging and decoration, advertising design and other industries.
However, as computers are widely used in the printing industry, the printing process technology has evolved from analog to digital, and the color desktop publishing system (DTP) widely used today has gradually evolved into a new process technology of computer-to-plate making. CTP (Computer to Plate) technology.
The concept of CTP technology The computer-to-plate technology (CTP) is a technology that uses a computer to directly copy graphic information to a plate through a laser plate maker. Can eliminate the film as an intermediate link, is to install a dedicated digital plate on the platesetter, digital imposition files are sent to the computer R, P, through the R, P electronic files sent to the platesetter, so that the electronic signal through the light Or thermal energy imaging on the plate, the plate processed after the plate is made, some CTP process also need to wet the plate material, and then directly on the machine printing. This technology is composed of a prepress system and a laser plate-making machine. It is called a computer-to-plate system and does not require laser imaging machines to output films, make imprints, copy and print, etc.
Advantages of CTP Technology Compared with DTP, CTP technology has the following advantages:
1 good plate-making performance, cancel the film. CTP technology does not require film, uses a new physical imaging technology, completely free from laser generation and the use of photosensitive materials, using inkjet devices to print the required graphics directly on the film, paper, PS layout, reducing the image transfer Number of times, really achieved 10% transfer, no content loss, direct output large-format, no imposition, revision, but the image is directly copied on the plate, so that the dot on the digital plate is a direct imaging Network points, which reduce the loss of the imaging network, can better restore the original color and gradation, so that print images more clean and clear.
2 Improve printing efficiency and shorten production cycle. Because this technology does not require procedures such as filming, rinsing, and printing, the time for plate making is greatly shortened. In particular, newspaper printing companies can postpone printing time and improve efficiency.
3 Simplified work flow, such as film cleaning, printing, traditional proofing, etc., can save manpower, investment in intermediate equipment, and plant area, making the plate making process easier.
430% of CTP equipment is equipped with a perforating device. Generally, the perforating process is performed after exposure. This can ensure accurate positioning of printing plates on the printing press, reducing prepress preparation time for printing roller adjustment, improving printing quality and overprinting. ,positioning accuracy.
In a word, the overprinting effect of the computer-directed plate material on the printing press will be better. When using the CTP printing plate, the amount of water needed to balance with the ink will be less. Therefore, it is easy to achieve a suitable ink density, reducing the original waste and preparation process.
Types of CTP Technology There are two types of computer-to-plate technology (CTP):
1. On-line direct technology This technical feature is the integration of laser platemakers and printers. At the time of plate making, the digital information edited by the computer is directly exposed to the water-free offset printing plate that has been mounted on the plate cylinder by laser, and is automatically cleaned into a printing plate, which is automatically registered and printed. The main application is the rapid short-run print market, with the best economical printing volume of 100 to 5,000.
2. Offline Direct Technology This technology is characterized by the separation of the laser platemaking machine from the printing press. At the time of plate making, the digital information of the factory is edited by the computer, and the plate is exposed directly to the laser by laser. After being punched and processed into a printing plate, it can be manually or automatically printed on the plate. Manually on the version of the machine is cheap, but generally requires a darkroom operation, so the efficiency is lower; and automatic version of the equipment, work efficiency, but the price is more expensive, generally more expensive than the manual model 100,000 US dollars about. Moreover, when the door-operated segment is squeezed into a blunt version, it must use a full-size printing plate with a release paper. There is a layer of light protection film on the surface of the plate, so it can be operated in bright room. In the upper version, the plate surface can be automatically peeled off by means of a plate feeder so that the plate can participate in plate making. This type of equipment is mainly used in mass-produced books, newspapers, and commercial printing markets.
The scope of application of CTP technology Currently on the market computer direct plate-making machine can be suitable for special large-format printing plate, size 55-inch by 67-inch; medium format printing plate, size 41-inch, 32-inch, 22-inch three; small format printing plate , size is less than 18 inches. It is also suitable for single and double color printing and four color printing, newspaper printing and form printing, financial printing, packaging printing and general commercial printing and other needs. Therefore, it is very flexible to use. In addition, in recent years, the types of plates have also been increasing. The plates used by the CTP system include the following types:
1 silver salt diffusion transfer type;
2 photopolymerization type;
3 Silver salt/polymer composite type;
4 thermal type.
The main problem in the transition from DTP to CTP is that CTP technology has many advantages and will be widely used in the future. This has been recognized by the industry at home and abroad. However, after several years of development, China's CTP technology has not yet been widely used. The reason is that there are various questions about the technical and economic aspects of the CTP system.
1. Technical issues 1 Pre-press digital process issues.
If direct platemaking technology is used, the printing plant must have the necessary prepress system. There are many printing companies because of the small size and lack of funds, there may be only printing presses and no prepress equipment, because there is a special output center that can output the film, and the printing factory can print and print as long as the film is received from the customer. However, if the printing factory adopts the direct plate making technology, all accepted digital documents provided by customers, the printing factory must purchase the corresponding prepress equipment, and if necessary, scan or modify the customer's work. This is also the case for the enterprise. This type of burden makes it difficult for such small-scale printing companies to reconstruct digital prepress processes. There is the digitalization problem of the film graphics. Prepress digitalization is based on the use of CTP technology. It is a very important issue for the customer to provide the traditional film artwork and how to make the film scan to solve its digitization process. After the film has been scanned, if the digital processing is not good, serious quality problems will occur. Therefore, companies need to carefully study how to use various software and scanning parameters. (To be continued)