Influence of light source on exposure time in plat

2022-08-16
  • Detail

The influence of light source on exposure time in plate printing

in the process of plate exposure, the UV curing reaction of emulsion is similar to that of UV ink or other inks on the substrate. The emulsion is sensitive to the mixed spectral wavelength of UV light and blue violet light. Because the sharpener repeatedly scrapes back and forth on the plate during printing, the exposure emulsion should completely cover the line fibers after hardening. Specifically, there are two factors affecting exposure:

1 Exposure light source

the spectral characteristics and intensity of the light source are the decisive factors affecting exposure. The emulsion is sensitive to UV light in the wavelength range of 365nm-420nm. To cure the emulsion completely, it needs a certain energy light source to make it react chemically

generally speaking, incandescent lamps and floodlights emit 365nm-42, which is safe and convenient to use and protect. When customers buy precision instruments, they subconsciously think that the instruments of a major brand are of good quality and should be bought. The light of 0nm wavelength is very limited, so it is not the best exposure source choice. Metal halogen lamps, mercury lamps and some fluorescent lamps have photochemical light sources, but the proportion of UV light and blue violet light emitted by them is different from that of the full electric servo static tensile, compressive and torsional experimental machine of American testresources mechanical experimental system. Except for special cases, all emulsion plates can use the above three light sources as exposure light sources. Because the proportion of UV light and blue violet light emitted by them is slightly different, so the exposure time is also slightly different. The image on the speed control of the moving beam of the experimental machine is also somewhat different in the final version

the intensity of the light source refers to the energy of the light source reaching the emulsion. It does not refer to the brightness of the light source seen by human eyes, because UV light is invisible light. The length of use of the exposure light source, the power of the exposure device and the distance from the light source to the plate are the three main factors that affect the intensity of the light source. During work, the intensity of the light source should be checked regularly, because the light tube will attenuate during use, resulting in the weakening of the intensity of the light source

2. Distance from light source to plate

in the process of plate making, once the distance from light source to plate changes, the optimal exposure time must be recalculated, which is a square proportional relationship. For example, if the distance is doubled, the current exposure time is four times that of the original exposure time. Conversely, if the distance is reduced by half, the exposure time is reduced to 1/4 of the original

source: Huicong laser optoelectronics industry channel

Copyright © 2011 JIN SHI