As a traditional technology, notebook printing can print all kinds of paper in the form of a book. Notebook printing includes all coil printing methods, such as flat, convex, concave, and mesh, and the application varies from country to country. Notebook printing covers several main printing methods. In the plate making stage, different printing methods are chosen according to the different product properties. For notebook office supplies, the plate making process also varies according to different printing methods.
The design of the original manuscript suitable for flexible printing should have the following characteristics: many colors but few overprints; no need to reproduce particularly small details; the halftone lines are not too high, but can achieve color printing effects; can be connected to packaging processing.
For plate making requirements, the graphics should be clear, and the size and specifications should be accurate; using frosted film, the four corners of the film should have consistent density; using photoresist; measuring with a transmission density meter, the white spot density should be below 0.06, and the black spot density should be above 3.5.
The support membrane of the photosensitive resin plate is upward, and the protective film is downwardly spread in the exposure drawer to receive exposure. The ultraviolet light penetrates the support film to solidify the photosensitive adhesive layer, which establishes a stable bottom base and can also control the washing depth and strengthen the bonding strength between the support membrane and the photosensitive resin layer. The back exposure time is determined according to the required bottom base thickness.
Also known as front exposure, the photosensitive resin plate support film faces downward, and the protective film faces upward. It is spread flat in the exposure drawer, the protective film is torn off continuously at once, and then the film's photoresist surface is pasted on the photosensitive resin plate. The main exposure time is determined by the plate type and the strength of the light source. If the exposure time is too short, the graphic slope will be too straight, the lines will be curved, and the small font and dots will be washed away. On the other hand, if the exposure time is too long, it will overexpose the plate, and the handwriting will be blurred. If there are large and small fonts, thick and thin lines on the same plate, cover them with black film for separate exposure according to the situation, so that the fine parts will not be lost due to washing to ensure the quality of the plate.
Wash away the unphotosensitive parts to retain the light-aggregated relief. The washing time is determined by the thickness and depth of the printing plate pattern. If the washing time is too short, resin that has not been photosensitive will be left on the plate, affecting the depth of the plate making. If the washing time is too long, the plate will expand, causing deformation or falling off of the fine parts.
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, thick plates take two hours, and thin plates take one hour. The baking time is too long, and the baking temperature is too high, which will make the plate brittle and affect the printing life. If the baking temperature is too low, the drying time will be extended, and if the drying time is too short, the printing will have a phenomenon of cracked plate.
That is, debonding and post-exposure. Thoroughly harden (polymerize) the photosensitive resin to the required hardness indicator and eliminate the stickiness of the printing plate to facilitate ink transfer. The post-processing time is determined by the test to ensure that there is no cracking or sticking.