The hottest label printing plate making process

Label printing plate making process

label printing covers several main printing methods. In the plate making stage, different printing methods are selected according to different product properties. For different printing methods, long-term clinical use also exposes many problems, and the plate making process is also different. In this paper, the flexographic plate making process is briefly introduced as an example

the flexo plate making process is: the original film (negative film) is exposed, washed and dried before processing

1. Manuscript

the manuscript design suitable for flexible printing should have the following characteristics: more colors, but less overprint; It is not required to reproduce particularly small details; The line is not too high, but it can achieve color printing effect; You can do packaging processing online

2. Film (negative)

meets the needs of plate making, with clear graphics and texts and accurate size specifications; Use frosted film, and the density of the four corners of the film is required to be consistent; Use film orthography; Measured by transmission densitometer, the white spot density is less than 0.06; The density of black spots is more than 3.5

3. exposure includes back exposure and main exposure

① back exposure

the supporting film of the photosensitive resin version is laid up and the protective film is laid down in the exposure drawer for exposure. UV light solidifies the photosensitive adhesive layer through the supporting film, so as to establish a solid base, control the washing depth, and strengthen the adhesion between the supporting film and the photosensitive resin layer. The back exposure time is determined according to the required subbase thickness

② main exposure

also known as front exposure, with the supporting film of the photosensitive resin plate facing down and the protective film facing up. Tile in the exposure drawer. Tear off the protective film once in a row, and then stick the film surface on the photosensitive resin plate. Cover the vacuum film inspection method on the film (non drug film vacuum pumping), so that the film is closely attached to the photosensitive resin layer. Ultraviolet light passes through the vacuum film and the transparent part of the film to polymerize and cure the photosensitive part of the plate. The length of the main exposure time is determined by the plate model and the intensity of the light source. Too short exposure time will make the slope of the text too straight, the lines bent, and the small characters and dots will be washed out. On the contrary, too long exposure time will apply the plate, and the handwriting will be blurred. If there are big and small lines, thick and thin lines on the same printing plate. Cover with black film and expose separately according to the situation. Small parts will not be lost due to washing, so as to ensure the quality of the printing plate

4. Washing

wash and dissolve the non photosensitive part, and retain the relief of photopolymerization. The length between firmness and smoothness during plate washing depends on the thickness of the printing plate and the depth of the image. If the plate washing time is too short, non photosensitive resin will be left on the plate, which will affect the depth of plate making. If the plate washing time is too long, the plate will swell, resulting in the deformation or falling off of fine parts

5. Drying

remove the washing solvent to restore the original size and thickness of the printing plate. The baking temperature is between 50-60 ℃. The baking time depends on the thickness of the plate and the length of the washing time. Generally, the thick version is two hours and the thin version is one hour. Too long baking time and too high baking temperature will make the printing plate brittle and affect the printing life. Too low baking temperature will prolong the baking time, and too short baking time will lead to bad version during printing

6. Post processing

refers to debonding and post exposure. Make the photosensitive resin harden (polymerize) thoroughly to reach the due hardness index, and eliminate the printing plate viscosity, so as to facilitate the ink transmission. The post-treatment time is obtained from the test in order to prevent cracking and adhesion

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