Influencing factors of inkjet printing quality

First, color conversion

In nature, all colors are composed of different wavelengths of light. When light passes through the prism, the spectra produced by the various wavelengths of light can be seen. "Spectral" can be said to be a natural phenomenon of continuous color mixing, but we can use it to define the color change and further manage the desired color. On television, movies, computers, and screens, we are dealing with color changes using the "add color method." It contains the main three colors: red, green, and blue (Red, Green, Blue), which is also known as the three primary colors (R, G, B). All colors can be overlapped by these 3 different colors of light. But for prints, the human eye uses reflected light to determine the difference in color. When you see a red paper, because the light is shining on the paper, the red light in the spectrum reflects, so you know it is red. of. Therefore, in the printed matter, the color must be defined using the "subtractive method", which is the so-called three-color model of C, M, Y (cyan Cyan, magenta Magenta, yellow Yellow). For colored light, red, green and blue can be mixed white light, but when using watercolor or paint to paint, they will find that the color will be deeper and deeper, red, green and blue are not white.

Therefore, using the three complementary colors of C, M, and Y to create a variety of different colors. However, since the addition of C, M, and Y colors does not mix pure black, the color printer then separates the black to form a complete subtractive color model for C, M, Y, and K. Perfect print quality. The color print quality must be able to truly represent colors; the "additive principle" and "subtraction principle" are the two major systems in color science. How to accurately convert the light source system's color (R, G, B) to ink jet or The printed system (C, M, Y, K) is a very complex science, but only by accurately converting colors can we achieve real high-quality results. Therefore, accurate color conversion technology is a key factor affecting print quality.

Second, the resolution

For black-and-white laser printers, resolution may be the key to print quality, but for color printers, color gamut and resolution are equally important. The DPI resolution is written by Dot Per Inch, which means that the number of dots can be printed in one inch width. In the case of black and white laser printers, the higher the resolution, the finer the resolution and the color scale points are, and the better the print quality is. But for color printers, the resolution refers to how many ink dots can be printed in a width of 1 inch, regardless of whether the ink dots overlap.

Third, color level

An output image is composed of many dots (or pixel pixels), and each dot forms this image with different colors and brightness. For example, on a television or computer monitor, beautiful picture quality can be presented, making our eyes feel very realistic. However, the resolution on a computer monitor is 640×480 dpi or 1600×1200 dpi, and the resolution of the television is even lower. Since the color is analog output, the voltage is used to control the color so that each point can be displayed in a continuous color gradation (full tone). So even if the resolution is lower than the printer, it still feels very natural and realistic, so the color scale is also very important. Therefore, some printers use six colors to print colors, adding the original C, M, Y, and K colors to light blue and light red. The advantage of this is that when color mixing is no longer just through The original C, M, Y, and K colors are colored, but the color quality is made closer to the continuous color gradation through 6 colors. As the number of primaries on the graph increases, the image becomes more realistic.

Fourth, the print head control

The ink dots are sprayed onto the paper through nozzles. In general, the nozzles and the print heads are made together. Therefore, the technology of the print head itself is very important, and the left and right print heads are the inkjet technology and printer cantilever gears and transmissions. The precision of the belt.

Fifth, ink

Inks can be classified into dye type (Dye Type) and pigment type (Pigment Type). Dye type inks have good saturation but poor water resistance; while pigment inks have less saturation than dyes, but good water resistance. . At present, inkjet inks are mostly dye-based, such as Epson and Canon's C, M, Y, and K all-color dye inks. The ink of the inkjet printer must have enough surface tension to prevent the ink from spattering when ejected. In addition, the ink must be fast-drying to prevent haziness on the paper. Therefore, the ink itself is also one of the factors that affect the print quality.

Six, was printed materials

All prints to be printed have an important relationship with the paper used. Just as we went to the photo booth to wash the photos, we could obtain different results on different photo papers. In the case of inkjet printers, because the paper fibers used in each paper are different, the ability to absorb ink is also different, and of course, the performance is different. Glossy photo quality is of course best in the form of photo paper; ordinary documents can be plain paper or inkjet special paper.

Author: Wang Fuhua, etc. Reprinted from: "Today's print"