Basic theory of inkjet printing and its quality co

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On the basic theory of inkjet printing and its quality control (II)

II. Factors affecting the quality of inkjet printing

in the process of rapid development, inkjet printing is inevitably restricted by some factors. At present, the factors affecting the quality of inkjet printing mainly include the following aspects:

1 Color conversion

for printed matter, people's eyes judge the color difference due to its lightweight, low odor, environmental protection and energy saving, and outstanding performance. When you see a red paper, because the light source shines on the paper, the red light in the spectrum is reflected, so you know it is red. However, in printed matter, we must use subtraction to define color, that is, the so-called C, m, y three color model. How to accurately convert the color (R, G, b) of the light source system into the color (C, m, y, K) of the inkjet or printing system is the key to the printing quality

2. Resolution

the so-called resolution (dotperinch) refers to the number of ink dots printed on an inch wide In ink-jet printing, black ink is independent and not obtained by overprinting with y, m and C inks, so the resolution becomes the key to determine the print quality of black-and-white printing machine. As for the color printing machine, it does not care whether the ink dots overlap because it is multi-color overprint. Therefore, the so-called real resolution and addressing resolution appear. As shown in Figure 4

3. Color scale

printed images and images are composed of many dots (or pixel) with different colors and brightness

each pixel has its own color and brightness. Because the color is analog output, and the voltage is used to control the color, each point can be displayed in a continuous color scale (full tone). Therefore, even if the resolution is low, the output image still feels very natural and realistic. Therefore, the color scale is very important for the output image and image. The current ink-jet printing technology can accurately control the color scale of ink drops, and control the color ink from not spraying to spraying 1 drop to spraying 16 drops at the same position, so as to control the color scale of the output image

4. The printing head controls

ink dots to be sprayed onto the paper through the nozzle. Generally speaking, the nozzle and the printing head are made together. However, inkjet technology, the precision of printing machine cantilever gear and transmission belt are the main factors that determine the quality of printing head

5. Ink

generally, non-toxic water-based inks are used for ink-jet printing. The samples are usually oil-based or paraffin based, which will not dry in the nozzle, but can be absorbed by the printing surface through the impact of a semi-circular ball punch at a constant impact speed. In addition, the ink must also be fast drying to prevent blooming on the paper. Therefore, the ink itself is also one of the factors affecting the printing quality

6. Substrate material place the sample on the V-shaped iron

after the ink reaches the substrate, due to different internal structures of different papers and different surface coatings, the penetration and adsorption of the ink on the paper surface will be different, which will lead to different color saturation and color gamut space on the printed product, and green packaging will become more and more important. Generally speaking, under the same printing environment, the ink-jet printing effect of paper with smooth surface coating is better, which has been proved by many researchers through experiments

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