Working principle and key technical problems of th

2022-08-01
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The working principle and key technical problems of the screen printing CTS system (II)

the key problems of the CTS system

rip

because the screen printing plate making can connect 10 actuators at the same time and work synchronously with halftone dots, the ink dots sprayed on the plate should also be dots. This is different from the general color printer. The raster image processor (RIP) needs to be used to interpret the page and generate the dot matrix image, and then the rip controls the printing point of the printing head. In fact, the rip of CTS system and the rip of laser Imagesetter have the same working principle and completed work, and both use the software rip

proofing

in order to check the effect of image color separation and whether the content of the page is wrong, digital proofing should be performed before output. If the problem is found after plate making, the loss will be large

resolution

the resolution of the laser exposure CTS system is high, up to 2540dpi, while the resolution of the inkjet CTS system is relatively low, generally only DPI. If the maximum resolution of the system is 720dpi, the maximum resolution of the final output is 75l/inch. Actual only 4. Maximum overall dimension: 905 × five hundred and ten × 870mm can achieve about 55l/inch. For the inkjet CTS system, too high resolution means small dots. However, too small dots may reduce the ability to block ultraviolet light, and can not block enough light during exposure, resulting in difficulties in developing. In addition, if the resolution is low, the imaging speed is much faster

ink blocking

dust, sand, and residual ink around the nozzle may seal the nozzle, resulting in ink failure. In order to prevent ink blocking, the ink head should be cleaned frequently and the environment should be kept clean

missing print

the nozzle is a complex device. It not only generates ink drops at the frequency of kHz, but also moves on the plate at a predetermined speed and direction. At this time, any external influence that plays a role of constant replacement in many utilization fields may cause missing prints or points to deviate from the normal position. For example, due to the influence of dust, air flow and static electricity, the flying direction of dots may shift, resulting in dot overprint and dot missing; For example, the impact of electronic impact on adjacent nozzles and the impact of ink-jet sound wave on adjacent nozzles will also affect that some nozzles cannot spray ink points, as well as the failure of nozzle heating elements, or the nozzle is electrically corroded, which will also affect that some nozzles cannot spray ink points

in order to solve the problem of missing printing, CTS system adopts the following technologies:

microwave technology

the method of printing continuous pixel lattice in this way is to subdivide spray points. In this method, multiple nozzles are used for multiple times to complete the printing of continuous areas, and each nozzle completes one time of printing separately. In this way, if some points of some nozzles in front fail to be printed, the subsequent printing will replace them. Even if some places are not stenciled, it is difficult to find the ideas that have been stenciled. This method includes 1, 2, 3 and 4 times of spray printing. However, the imaging speed is greatly reduced

spray point coverage technology

this method produces so many ideas that you can't see them at all. This method is very slow and consumes a large amount of ink

turn off some nozzle technology

the drive software of some CTS systems allows the operator to select the number of nozzles or specify the nozzle array to work. In this way, some nozzles will not be "excited" during inkjet in 2017. The operator can use this command to remove those nozzles that cannot be inked. During operation, the CTS system can use the remaining nozzles to re image where the nozzles are closed

With the increasing number of outdoor large format advertisements and the emergence of some special printing materials, commercial printing companies are now taking printing seriously. The printed matter obtained by plate printing has thick ink layer and bright color. After polishing and printing, the printed matter has been able to withstand the impact of outdoor natural conditions. Therefore, plate printing has become the preferred printing method for some printed materials

it is easy to say, but difficult to say, to obtain a good print. The key lies in how to effectively control the exposure during plate making? How to make a good edition? In practical work, printers are often at a loss about the exposure time. Whether the exposure process is correct or not determines whether high-quality printing can be obtained finally. How to avoid exposure errors? The first step is to listen to the suggestions of emulsion suppliers, who have a direct understanding of their own emulsion products, so their suggestions are constructive. Secondly, tests should be carried out according to the specific conditions of the company or the printing workshop, so as to determine the best exposure time. Because in the process of plate printing, many changing factors determine the exposure time recommended by others. It is only a reference standard. To achieve the best exposure, it is necessary to conduct tests. This is the truth that practice produces true knowledge! Now, let's focus on several key issues related to version exposure

(to be continued)

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