Fluorescent Printing -- Application Of Screen Printing Special Printing Technology

fluorescence printing It is different from luminous printing. Fluorescence was first discovered in natural fluorite (also known as fluorite). Under the irradiation of ultraviolet rays (such as sunlight), it can emit a non primary colored light. It is called fluorescence flashing. It is not caused by the reflection of light caused by high temperature. When the light source is removed, there is no reflected light and flash phenomenon. This is different from phosphorescence. Fluorescence is a kind of flash. It can reflect ultraviolet light into visible light, increasing the number of reflected light and increasing the brightness. For example, a common fluorescent brightener, it absorbs ultraviolet light which is invisible to the naked eye in the return light and reflects blue or blue-green light. It can cancel the yellow light which is complementary to each other on cotton cloth and make the cotton cloth more white. Fluorescent paint itself is not a luminous dye. In short, it is a fluorescent brightener with a main color. The more ultraviolet radiation it is, the stronger its fluorescence will be emitted. Its main color will not increase. Under the irradiation of monochromatic visible light without ultraviolet, it will only show its dominant color without fluorescence. This is also the place where fluorescent paint (or dye) is different from ordinary dyes. For example, the fabric dyed with common dyes, such as salt lake blue, becomes black rather than bluish because of ultraviolet radiation. Ultraviolet light does not contain any blue-green and any visible light. But if the fabric dyed with strong fluorescent base rose red is irradiated under the same ultraviolet light, it will produce bright red yellow fluorescence. This means that it can turn ultraviolet short wave into long wave visible in the inner eye.

When the dye absorbs the light quantum in the light, the dye molecule is intensified into an intensifying state, and through the molecular collision or other action, the absorbed energy can be released in various forms. The form of energy release can be heat energy, light energy (i.e. fluorescence), chemical energy (mainly Photochemistry), or decomposition energy. dyestuff Decomposition).

General dyes mainly convert energy absorbed into heat, and only a small part is converted into chemical energy. Fluorescent dyes are mainly converted into light energy, and only a small part is converted to thermal energy and chemical energy. Because the wavelength of light reflected by fluorescent paints (or dyes) is longer than the wavelength of absorbed light, the fluorescence band emitted is always on the long wavelength side of the absorption band. As a result, yellow dye absorbs blue light and fluorescence is blue-green light (or green light). Therefore, yellow fluorescent paint will be more blue or green than the non fluorescent yellow dye. At the same time, the quantity of reflected light of fluorescent paint (or dyestuff) will increase. The more the reflected light, the better the fluorescence. The quality of fluorescence is measured by this quantity. In fact, many dyes have fluorescence characteristics, but their fluorescence does not all fall within the visible spectrum. We can not see it by naked eyes. The above fluorescent paint (or dye) refers to those coatings or dyes that can increase the amount of reflected light under sunlight, so it should be called "fluorescent fluorescent dyes".

Fluorescent printing and general screen printing Technology In the same way, the preparation of printing paste needs only fluorescent dyes.