1. What is CTP?

CTP includes several meanings:

Offline computer-to-plate

Machine-to-press

Direct-printing (Computer-to-paper/print)

Digital-proofing (Computer-to-proof)

Ordinary PS plate direct plate making technology, namely CTcP (Computer-to-conventional plate)

The CTP system discussed here is Computer-to-plate. CTP is the computer directly to the printing plate, a digital printing plate imaging process. The structure principle of the CTP plate-making machine and the image-setter is similar. The plate-making equipment is controlled directly by a computer, scanned by a laser, and then directly printed on the plate by developing and fixing. Computer direct plate making is a digital workflow that directly converts text and images into numbers and directly produces printing plates, eliminating the need for film materials, artificial imposition, semi-automatic or fully automatic printing processes.

2. When did the CTP come from?

The concept of CTP originated from the idea of ​​an American in 1978, but due to various reasons of technology and media, CTP really developed in the 1990s. At the German DRUPA exhibition in 1995, CTP made its debut on a large scale, and it quickly developed.

3. What is the basis for the operation of CTP technology?

Digital workflow and management are the necessary conditions and the key to the operation of CTP technology. Most companies use a standardized workflow technology to manage the prepress process, with CTP output as the goal, and gradually achieve digital photography, digital proofing, portable file format (PDF) output, color management, digital process management, network transmission, and ultimately realize the full Digital process.

4. Technical characteristics of CTP

The main features of CTP are as follows:

1 completely eliminate the film process and the corresponding materials, greatly simplify the process, significantly shortening the plate-making time;

2 can output a variety of format plates, to meet the press requirements;

3 Plates can be accurately positioned during platemaking to ensure plate registration requirements;

4 High resolution, with an output accuracy of 3000 to 5000 dpi;

5 can form 175 ~ 300lpi, 256 tone network;

6 plate making speed, can make a printing plate in a few minutes;

7 Four-color printing plate overprinting accuracy, to meet the printing requirements, and can prevent the occurrence of moire phenomenon caused by dot shape, angle;

8 has good operability, can automatically transport, automatic exposure, automatic development, to ensure accurate printing plate production;

9 can produce good economic benefits.

5. How CTP Technology Works

The CTP plate making machine consists of three parts: precise and complex optical system, circuit system, and mechanical system. 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.

6. What are the basic concepts of the CTP system?

The CTP system is composed of equipment, plates, software, and technical support. It consists of direct platesetters, plateetters, printing plates, distribution software, RIP, system management software, after-sales services, and spare parts supply.

7. CTP system classification

From the exposure system can be divided into: inner drum, outer drum, flat, curved four categories. Among these four types, the most used are the inner drum type and the outer drum type; the flat type type is mainly used for large format plates such as newspapers; the curve type is the least used.

From the variety of plate materials can be divided into: silver salt version, thermal plate (ablation thermal plate, non-ablation thermal plate), photosensitive resin plate

And polyester version (non-metal base), etc.;

From the technical aspects can be divided into: thermal technology (ordinary laser imaging), purple laser technology, UV light source technology;

From the degree of automation can be divided into: manual stand-alone, semi-automatic, fully automatic and hybrid (CTF-computer to film and CTP-computer to plate).

From the aspect of the fixing method of the printing plate on the drum, it can be divided into: full adsorption type and middle adsorption, and two kinds of fixing are used for the first and the end. There is no limit to the size of the plate for full adsorption, and the size of the plate for the clip type must be fixed.

From the application can be divided into: commercial CTP system and newspaper with CTP system.

8. What is a RIP RIP? What role does it play in a CTP system?

Raster Image Processor RIP, short for English Raster Image Processor, is an indispensable intermediate link from pre-press layout to output film or plate. It is related to the quality and speed of output, and even the operating environment of the entire system, is the core of the entire system. The main function of RIP is to accept the data transmitted from the computer and "translate" it into the raster data information needed by the output device for output. RIP also has the role of controlling the output device and controlling the output of other information on the layout. It can be said that RIP, as a "translation" for digital proofing machines and imagesetters, etc., is an indispensable pivotal link for exporting computer-supplied graphic pages to different media and plays a crucial role.

9. What are the components of RIP?

RIP consists of microcomputers and operating system software, RIP encryption locks, interface cards and data cables connected to RIP and output devices, RIP software, and fonts.

General RIP can be divided into hardware RIP, software RIP, and RIP combined with hardware and software. The hardware RIP is actually a dedicated computer that specializes in the interpretation of page information. The software RIP uses the software to perform page calculations and passes the parsed information to the CTP platesetter. Therefore, the software RIP must also be installed on a computer. However, with the significant increase in the speed of computers, software RIP's interpretation algorithms and screening algorithms have also been continuously improved, and software upgrades have become easier, and they have become more and more popular with users.