CTP system plate process flow and its requirements

The CTP mentioned here refers to the CTP system, not the simple CTP platesetter. Realizing any new technology is a complex issue. A CTP system not only means installing a platesetter, but also includes a number of additional devices and devices that allow digital workflows to run. CTP technology includes plates, corresponding output devices, and corresponding workflows.

CTP direct plate making process

Computer Digital File - CTP Workstation - Trapping/Color Management/OPI/Electronic Imposition - Digital Proofing - CTP Plate - Printing (CIP3).

Traditional laser photocopying process

Computer typesetting - Phototypesetter output plate-making film - film after punching machine - developing - fixing - drying - artificially spelled the film on the PS plate - vacuum absorption of the sun PS version - development processing - revision - printing - printing.

Through the comparison of the above two platemaking processes, it can be seen that the CTP plate making process is fast and simple and realizes 100% transfer. The entire process is fully automated. Generally, it takes only 8 minutes; while the laser imaging process requires 55 minutes. In addition, because the CTP platesetter adopts a fully-automated integrated solution, it avoids the distortion of manual imposition and revision in the laser photocopying and improves the quality of plate making. The second is to omit the investment of many equipment and the consumption of raw materials. Such as laser phototypesetting machine, punching machine, printing plate machine, developing machine and plate receiving machine and film, chemical agents and so on. Once again, the CTP machine can realize the direct plate making of long-distance transmission data through satellite digital signals and computer networks, which greatly shortens the gap between time and space. For example, in the newspaper and magazine industry, due to the fierce competition in the current newspaper market, publishing newspapers requires fast time and high quality. Along with the development trend of color newspaper printing, CTP plate making has become the best means to effectively achieve the above goals.

The main differences between computer-to-platemaking and traditional printing processes are:

CTP technology plate, no Film.

Use the CIP3 print production format.

Digital proofing.

Digital layout.

CTP system requirements

When using the CTP system, first of all, it is necessary to pay attention to the interface technology with the front-end system, that is, the data exchange technology between the color prepress processing systems, and the improvement of the data and technology of the back-end devices. For large-capacity files, data exchange speed and data transmission speed are of utmost importance. Secondly, companies are required to establish a complete set of new electronic document management systems, improve data preservation and retrieval technologies, and then apply color management technologies and RIP technologies. The requirements are also very important. Large-capacity files require RIP's powerful processing capabilities to achieve efficient work efficiency. For the consistency of proofing and output, it is necessary to participate in color management technology.

CTP plate working principle

The single-beam original laser generated by the laser is split into multiple beams (usually 200-500 beams) through multiple optical fibers or a complex high-speed rotating optical splitting beam system. Each beam of light is transmitted through an acousto-optic modulator. The bright and dark features of the image information in the computer modulate the bright and dark changes of the laser beam and then become controlled beams. After focusing, several hundred micro lasers directly hit the surface of the printing plate for engraving work. After scanning and engraving, the latent image of the image is formed on the printing plate. After development, the image information on the computer screen is restored on the plate for direct printing by the offset press. The diameter of each micro laser beam and the light intensity distribution shape of the beam determine the sharpness and resolution of the latent image formed on the plate. The smaller the beam spot, the closer the light intensity distribution of the beam is to the rectangle (ideal case), the higher the sharpness of the latent image. The scanning accuracy depends on the mechanical and electronic control parts of the system. The number of laser microbeams determines the length of the scan time. The greater the number of microbeams, the shorter the time for etching one plate. At present, the beam diameter has been developed to 4.6 micrometers, which is equivalent to the printing accuracy of 600lpi. The number of beams can reach 500. The etching time of a pair of printing plates can be completed in 3 minutes. On the other hand, the higher the output power and the energy density of the plate beam (laser energy per unit area, in joules/cm2), the faster the etching rate. However, too high power also has the negative effect of shortening the working life of the laser and reducing the beam distribution quality.

The source of the platemaking machine includes: a gas laser (argon ion laser 488 nm, power: about 20mw); a solid-state laser (FDYAG532nm, 100mw or more); a semiconductor laser (LD, an infrared semiconductor laser among semiconductor lasers has the advantages of low power and long lifetime.)