来源:http://www.njhxsfs.com/ 日期:2019-05-05 发布人:admin   标签的广泛应用以及标签品种的不断发展自然而然地推动了标签印刷技术的发展。标签印刷涵盖了平、凸、凹、网等所有印刷方式,各国的应用情况不尽相同。不干胶防伪标签印刷涵盖了几种主要的印刷方式,在制版阶段。根据不同的产品性质,选择不同的印刷方式,针对不同的印刷方式,制版工艺也有所不同。
  The wide application of labels and the continuous development of label varieties naturally promote the development of label printing technology. Label printing covers all printing methods, such as flat, convex, concave, screen, etc. The application situation in different countries is different. Non-adhesive anti-counterfeiting label printing covers several main printing methods, in the plate-making stage. According to the nature of different products, different printing methods are chosen, and the plate-making process varies according to different printing methods.
  The process flow of flexographic plate making is: manuscript - Film (negative film) - exposure - flushing - drying - post-processing.
  1. original manuscript. Manuscript design suitable for flexible printing should have the following characteristics: more colors. However, there are few overlays, no need to reproduce very small details, the screen line is not too high, but it can achieve color printing effect, and online packaging processing can be done.
  2. Film (negative film). It meets the requirements of plate making, with clear pictures and text, accurate size and specifications; with ground film, the four corners of the film are required to have the same density; with film orthography; measured by transmission densitometer, the white density is less than 0.06; and the black density is more than 3.5.
  3. Exposure includes back exposure and main exposure.
  Back exposure. The supporting film of the photosensitive resin plate is laid up and the protective film is laid down flat in the exposure drawer for exposure. Ultraviolet light passes through the supporting film to solidify the photosensitive adhesive layer. In order to establish a solid base, also can control the depth of plate washing, strengthen the support film and photosensitive resin layer bonding force. Back exposure time is determined according to the required base thickness.
  (2) Main exposure. Also known as positive exposure, photosensitive resin plate support film facing down, protective film facing up. Flat in exposure drawer. The protective film is torn off one time in succession, and then the film surface is pasted on the photosensitive resin plate. The vacuum film is covered flat on the film (non-drug film surface) and vacuum is pumped to make the film adhere closely to the photosensitive resin layer. Ultraviolet radiation penetrates through the vacuum film and the transparent part of the film, so that the photosensitive part of the plate can be polymerized and cured. The length of main exposure time is determined by plate type and light source strength. Short exposure time will lead to too straight slope, curved lines, small words, small dots washed out, and conversely, too long exposure time will cover the plate, the handwriting is blurred. If there are big and small lines on the same plate. Black film is used to cover and expose separately according to the situation. Small parts will not be lost due to flushing to ensure plate quality. The main operating points of the main exposure are shown in Table 1.
  4. rinse. The non-photosensitive part is washed and dissolved, and the relief of photopolymerization is retained. The length of plate washing depends on the thickness of plate and the depth of print. If the time of plate washing is too short, there will be no light-sensitive resin left on the plate, which will affect the depth of plate making. If the plate washing time is too long, the plate will expand, resulting in deformation or shedding of fine parts.
  5. drying. Remove the solvent to make the plate return to its original size and thickness. The baking temperature ranges from 50 to 60 degrees Celsius. The baking time is determined by the thickness of the plate and the length of the washing time. Generally, the thick plate lasts two hours and the thin plate lasts one hour. If the baking time is too long and the baking temperature is too high, the plate will become brittle and the printing life will be affected. Too low baking temperature will prolong the drying time, too short baking time, printing will appear rotten plate phenomenon.
  6. Post-processing. That is, debonding and post exposure. Make the photosensitive resin harden thoroughly (polymerization) to meet the required hardness index, and eliminate the plate stickiness, in order to facilitate ink transmission. The post-processing time is obtained from the test in order not to crack or stick.

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