As is known to all, CTP process can bring many benefits to printing: excellent imaging quality, nearly perfect calibration, and rapid production turnover. However, its advantages are not only attributed to imaging equipment, but also depend on the quality and performance of CTP plates.
In this paper, we will focus on several characteristics of plate materials to see how they interact with each other to assist CTP equipment in digital plate making, thus affecting the image quality. This applies to all CTP plates, but especially to heat sensitive plates. At present, the use of heat sensitive plates worldwide has increased dramatically, and has been recognized as the preferred plate for high-quality lithography.
The requirement for an aluminium base
In traditional plate-making, branches can accurate positioning on the plate, largely depends on the use of vacuum device or device for continuous replication puzzle and locate the position of the alignment device is accurate. No matter what, this need in the flat plate is quite smooth, but as a result of the imaging process adopts direct contact exposure method, the whole process can accept the change of the various types of plate surface roughness, and the surface roughness changes are manufactured by the traditional plate of aluminum surface treatment. However, because the digital printing plate is exposed with the energy focus from the laser light source, the requirement for the flatness of the digital plate, including the treatment of aluminum substrate surface, is more stringent.
In addition, the use of energy focus imaging and direct imaging in different ways and means in the digital imaging on the plate when there will be no visible stripes, because in the aluminum anodic oxidation and grinding processing edition of stripe is not produced.
Photosensitive emulsion coating on the digital plate must be smooth, uniform, and without defects. Because the laser plate maker directly generated on the node size is very small, in the process of drum production any dust in the air, no matter how small, fell on the plate, will result in an artificial this image points. In fact, it can also produce irregular images due to static spots, and it's so small that you can't even see it with a magnifying glass that examines a traditional print material.
The same uniformity requirement is applied to the photosensitive coating of digital printing plate materials. Generally speaking, when the traditional printing plates was exposed in the ultraviolet (uv) light, its accept about 10000 times the energy in laser direct plate-making equipment system to digital print material coating of energy. This means that in order to accurately meet the physical properties of the mentioned above, the emulsion coating of digital printing plates have to be very strict to reach a particular scope spectrum characteristic, satisfy is a synthetic substance (especially the molecular architecture of coating), and the reaction active energy. Therefore, the production of digital printing plate materials requires special, additional chemical agents, but also special production workflow.
Operation requirements
Compared with traditional plate materials, CTP plate materials also require different operation modes in the handling process. Because many digital plate imaging plate edge as a key reference point for calculating imaging location. Digital plates have very strict requirements for edge straightness and evenness. Although this is only a minor problem for traditional plates, if the edges of digital plates are not straight, unusual or damaged, the plates will not work properly.
The final step in the production of digital materials is to create and maintain a service team that can help printers solve problems whenever and wherever problems arise. This is an issue that should be considered when evaluating any traditional and digital material, but is especially important for digital material. Because CTP printers are generally produced because customers have a very strict time limit, which means problems must be resolved as soon as they occur.
In comparing different digital plate or plate making system, it is important to note that the final product is not sent to the printing shop after a pile of plate but by accurate imaging of trouble-free on printing machine printing plate produced printing quality. When considering the cost of producing digital plate, we should consider several important factors that the cost is higher than that of traditional plate. The most important point is the demand for high-quality raw materials. Thermal sensitive technology is the preferred technology for printing companies to adopt CTP system. Thermal sensitive plate will bring accurate quality and stable high quality to users.