As a kind of environmental protection printing, flexible printing has developed rapidly as people's awareness of environmental protection has been increasing. However, early hand-engraved rubber plates can no longer meet the higher printing requirements such as more visualization, leveling, and exquisiteness required at the present stage. In 1973, DuPont Co., Ltd. took the lead in the development of a cyrel photosensitive resin flexo. This version has a high elasticity, high resistance to print, high image resolution, make up for the deficiencies of the rubber plate, so this resin version has gradually replaced the rubber plate. Of course, to produce high-quality printing plates, high-quality plate-making technical personnel must also cooperate with high-grade flexible plate-making equipment. The purpose of this article is to discuss the flexible platemaking process. Let us first introduce the technical features of the flexible platemaking machine by taking the KMY type flexible platemaking machine as an example.
First, the flexible platemaking machine KMY flexible platemaking machine set exposure, washing, constant temperature drying, post-processing four processes in one. All production procedures are controlled by microcomputer components. Accurate data, high accuracy, and simple operation. The device functions as follows:
1. Exposure: Use imported special plate lamp as exposure light source to ensure the stability of the light source.
2. Wash plate: use two-way automatic washing plate, wash plate brush fine, good stiffness, can make dot version of 1:50 lines / inch and relatively fine lines and small text.
3. Bake version: with automatic thermostat device, so that heating is even and effective.
4. Post-processing: The use of imported Philips in addition to sticky tubes mixed exposure lamp, saving time and improve work efficiency.
Second, the flexible version of the plate making process Flexo plate version of the process is: manuscript → film (female) → exposure → rinse → drying → post-processing.
1. Manuscript: Original manuscript for flexible printing should have the following characteristics: 1 more colors, but less superimposition; 2 does not require reproduction of particularly small details; 3 network cable is not too high, but can achieve the design of the color printing effect; 4 can Online packaging design.
2. Film (fungy) flexo platemaking film has the following requirements: 1 meet the needs of plate making, graphic and clear, size and size specifications are accurate; 2 use frosted film; 3 film requires the same density of four corners; 4 use the film orthographic; Measured by a density meter, the concentration of white spots was 10g 0.06 or less, and the concentration of black bits was 10g3.5 or more.
3. Exposure: divided into back exposure and main exposure:
1 Back exposure: The supporting film of the photosensitive resin plate is pushed down the protective film and is exposed in the exposure drawer. The ultraviolet light passes through the supporting film to photosensitize the sensing light resin. The purpose is to establish a solid foundation to support the projected image part, and to control the depth of the plate, and to strengthen the binding force of the support film and the photosensitive resin layer. The back exposure time is determined based on the required substrate thickness.
2 Main exposure: The supporting film of the photosensitive resin plate faces downward and the protective film faces upward. Tiling in the exposure drawer, remove the protective film once and continuously. Then, the film of the film is pasted on the photosensitive resin plate, the vacuum film is laid on the back of the film (non-pharmaceutical film surface), and then the vacuum pump is turned on so that the film and the photosensitive resin layer are closely attached. Ultraviolet light passes through the vacuum film and the transparent part of the film, which causes photopolymerization of the light receiving part of the photosensitive resin to produce insoluble matter. The length of the main exposure time is determined by the plate type and the intensity of the light source used. If the exposure time is too short, the slope of the plate will be too straight, the lines will be bent, and the small print and small dots will be washed away. On the other hand, if the exposure time is too long, the Yin script will become contaminated, the writing will be blurred, and the anti-white and anti-white points will be filled. If there are large and small characters on the same printing plate, thick and thin lines, the black film can be used to cover the separate exposures as the case may be, and the fine parts will not be lost when washing to ensure the plate quality.
4. Flushing: The function is to make the part not exposed to light in the exposure process dissolve in the rinsing solvent under the action of the brush on the rinsing device, so that the photosensitive resin that receives the ultraviolet ray to produce the photopolymerization reaction remains to form the convex-concave relief. The length of the washing process is determined by the thickness of the printing plate and the depth of the print. The washing time is too short. The unsensitized resin on the plate will affect the plate-making depth. Too long washing time will cause the plate to swell too much, causing fine lines. Part of the risk of deformation or detachment.
5. Drying: The role is to volatilize the printing solution in the printing plate to restore the plate to its original size and thickness. Drying temperature is generally between 50 °C -65 °C. The drying time is determined by the thickness of the plate and the length of the washing time. The thick plate is generally 2h and the thin plate is 1h. Too long drying time and too high baking temperature will make the printing plate brittle and affect the printing life. If the drying temperature is too low, the drying time will be prolonged and the drying time will be too short. This will cause rotting in the printing process.
6. After treatment: that is, in addition to sticking and exposure. The main purpose is to make the photosensitive resin of the printing plate completely hardened (polymerized) to a proper hardness standard, and eliminate the tackiness of the printing plate, so that the surface of the printing plate has a good ink transmission effect. The post-processing time was obtained from the test for the purpose of not cracking or sticking.
The above introduces the KMY type flexible platemaking equipment and plate making process flow. With the rapid development of printing technology, our factory will keep pace with the times, and we will continue to develop better flexible platemaking equipment and provide them with the best service.