Notebook print in China
10-30-2020 19:58:34

Notebook printing covers several main printing methods. In the plate making stage, different printing methods are selected according to different product properties. Plate making process is also different for different printing methods. Flexographic plate making process is: manuscript film (negative) exposure - Development - drying - post-processing.

1. Original.

The original design suitable for offset printing should have the following characteristics: more colors but less overprint; no need to reproduce very small details; the screen line is not too high, but can achieve color printing effect; online packaging processing can be done.


2. Film

It meets the needs of plate making, with clear picture and text, accurate size and specification for the notebook printing; with frosted film, it is required that the density of four corners of the film is consistent; the use of film orthography; the white density is less than 0.06; the black density is more than 3.5.3.

3. Exposure includes back exposure and main exposure.

Back exposure.

The supporting film of the photosensitive resin plate is upward and the protective film is laid downward in the exposure drawer to receive exposure. UV light can solidify the photosensitive adhesive layer through the supporting film to establish a stable base. It can also control the plate washing depth and strengthen the adhesion between the support film and the photosensitive resin layer. The back exposure time is determined according to the thickness of the substrate required.

Main exposure.

Also known as positive exposure, photosensitive resin plate support film down, protective film up. The protective film is torn off continuously, and then the film surface is pasted on the photosensitive resin plate. The ultraviolet ray penetrates the vacuum film and the transparent part of the film to polymerize and solidify the photosensitive part of the plate. The main exposure time is determined by the plate type and light source strength. If the exposure time is too short, the gradient of the text will be too straight in notebook printing, the lines will be bent, and the small characters and dots will be washed out. Otherwise, if the exposure time is too long, the plate will be overlaid and the handwriting will be blurred. If there are large, small, thick and thin lines on the same plate, black film can be used to cover and expose separately. Small parts will not be lost due to washing, so as to ensure the quality of the plate.

4. Rinse.


The non photosensitive part is washed and dissolved to retain the light polymerized relief. The washing time depends on the thickness of the plate and the depth of the image. If the washing time is too short, the plate will leave non photosensitive resin, which will affect the depth of plate making. If the washing time is too long, the plate material will expand and the fine parts will deform or fall off.


5. Drying.


Remove the washing solvent, so that the plate to restore the original size and thickness of the notebook printing. The baking temperature is between 50-60 ℃. Baking time depends on plate thickness and plate washing time, generally two hours for thick plate and one hour for thin plate. If the baking time is too long and the plate temperature is too high, the printing plate will become brittle and affect the printing life. If the baking temperature is too low, the drying time will be prolonged. If the baking time is too short, the printing plate will be rotten.


6. Post treatment.


That is, debonding and post exposure. Make the photosensitive resin harden completely (polymerize) to reach the required hardness index, and eliminate the printing plate viscosity, in order to facilitate the ink transfer. The post-processing time is obtained from the test to avoid cracking and adhesion.

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