ink jet Printing was launched by Siemens in 1951 and has achieved considerable success after half a century of development. In particular, recent fast, high-quality inkjet printers have gradually been applied to the production field, and inkjet printing has expanded from the field of large-format advertising, label printing, bar code printing and the like to the field of color short printing.
In Epson's inkjet technology, its core technology, the Perfect Picture Imaging System, consists of four parts: (1) the print head part, Epson's unique micro-piezo printing technology, inkjet Surface control technology, etc.; (2) algorithm part, that is, fine image network adjustment technology; (3) medium part, that is, printing medium suitable for various fields; (4) ink part, inkjet printing ink is inkjet One of the core technologies in printing, and ink selection for inkjet printing is directly related to the print head and substrate used in inkjet printing. At present, the world's leading professional inkjet printer manufacturers have developed different special inks for their models to adapt to various printing environments to achieve satisfactory printing results. For a variety of dedicated inkjet inks have always been a high degree of trade secrets of companies, so the relevant details are difficult to obtain, therefore, this article will mainly discuss the common problems of inkjet printing inks.
Basic components of inkjet ink
The basic components of inkjet inks are: color formers, binders, solvents and auxiliaries.
(1) Coloring agent: A coloring agent, also known as a coloring matter, is contained in an amount of 1% to 10% by weight based on the total weight of the ink, and includes a pigment and a dye, and the effect is to make the ink exhibit a different color. The quality of the color former directly affects the print quality.
Pigments and dyes have advantages and disadvantages as ink coloring agents for inkjet inks, and have their respective fields of application. Pigments have more stable light and chemical resistance than dyes and produce more saturated colors. However, the insolubility and particle size of the pigments make it a challenge in the use of ink jet printing. For example, when carbon black and titanium dioxide have been widely used, there are some limitations in the application of other pigments. Secondly, the dye is soluble and the pigment is insoluble, so the use of pigments requires the application of certain dispersion stability techniques. At the same time, when the pigment particle size is reduced to submicron order (100 nm to 1.0 μm) as needed, dispersion is required to be stabilized and the occurrence of agglomeration is restricted.
In general, the pigment particle size is required to be less than 1 μm in on-demand inkjet printing; the particle size is required to be less than 0.5 μm in continuous inkjet printing; in foamed inkjet printing, the ink is "microbubbles" due to the continuous use of heat. Therefore, it is very important to have a heat-resistant colorant; in aqueous inks, dyes and pigments are often used; in oil-based inks, pigments are generally used.
(2) Linking materials: all kinds of resins and solid chemical raw materials used for film formation, the binders impart rheological properties (dynamic properties) of the ink, and the content thereof is 40% to 90% of the total weight of the ink, which is the viscosity of the ink, The basis for the formation of fluid droplets. When the ink is printed on the substrate, the binder must also impart good film-forming properties to the ink, such as adhesion and gloss of the ink film. The binder must be completely soluble in the solvent, the viscosity is between 2 and 10 mPa·s, and the concentration (by weight) is above 20%. The ink binder resin commonly used in continuous inkjet printing is phenol resin, polyvinyl butyral or the like.
(3) Solvent: The solvent is mainly used to dissolve the binder and keep it in a liquid state (fluid). Different kinds of binders have different solubility, and the solvent dissolving ability and volatilization rate are also different. Therefore, the optimal solvent combination and ratio should be selected according to the type of binder and inkjet printing process requirements. In general, the solvent is required to improve the stability of the ink, and the viscosity, surface tension, and the like of the ink are not easily changed with temperature, thereby causing the ink to form a thin and brittle film at the nozzle, which is easy to dissolve during printing without clogging the nozzle. The ink dries quickly during the film formation process.
In general, for solvent-evaporated dry inks, the evaporation rate of the solvent directly affects the film-forming properties of the binder during the film formation process of the ink, which is related to the composition, concentration and temperature of the solvent; for foamed inkjet printing In the case of ink, the solvent added thereto also needs to have good heat resistance due to heat, and the ink foaming is stable and uniform; for aqueous ink, the solvent is generally deionized water, and then appropriate A mixture of a water-soluble organic solvent (0.1% to 1.0% by weight based on the total weight of the ink); for a solvent-based ink, the solvent is generally an organic solvent, and an appropriate amount of water is added.
(4) Additives: The additives commonly used in inkjet inks include surfactants, dispersants, pH adjusters, driers, conductivity control agents, preservatives, viscosity modifiers, etc. Performance can play an important role and ensure good ink printability.
The role of the surfactant is to change the surface tension of the ink so that the surface tension of the ink is controlled within an appropriate range. The lower the surface tension of the ink, the smaller the contact angle of the ink droplets with the paper, and the larger the diameter of the dots formed on the paper by the ejected ink droplets, which contributes to obtaining high-quality graphics. However, if the surface tension of the ink is too low, it is difficult to form minute and uniform ink droplets. As the aqueous ink, a surfactant which is usually used is a benzsulfonate, an ammonium salt, an alkylamine oxide or the like, and it generally accounts for 0.1% to 1.0%, preferably 0.5%, based on the total weight of the ink.
As described above, when a pigment is used as a coloring material, it is necessary to ensure dispersion stability in the ink, and a dispersing agent serves this purpose. For the aqueous ink, a water-soluble pigment-dispersing resin is usually used, and its preferred concentration is 0.05% to 2.0% based on the total weight of the ink. For the solvent-based ink, a polyester-based polymer compound is often used as a dispersing agent, and it is preferably used in an amount of from 30% to 120% of the coloring agent.
The pH adjuster, also known as a buffer, is used to adjust and control the pH of the inkjet ink. Since the nozzles of the ink jet printer are generally metal, the ink reaches the substrate via the nozzle during printing. To avoid corrosion of the metal nozzle by the inkjet ink, the ink is required to remain neutral or weakly alkaline. Commonly used pH adjusters are ammonia, trimethylamine, sulfate, and the like.
The drier can cause the ink to dry quickly after the ejection nozzle reaches the substrate, and the drying time is generally required to be about several microseconds. Commonly used driers for inkjet inks are ethanol, isopropanol and the like.
Adding other additives will change some properties of the ink: such as adding metal ion chelating agent to avoid precipitation of heavy metal ions and reducing nozzle clogging; adding preservative to prevent deterioration of ink; adding conductivity control agent can adjust the conductivity of ink, etc. .
Amino acids are biologically important organic compounds composed of amine and carboxylic acid functional groups, along with a side-chain specific to each amino acid. With biological significance, amino acids are important in nutrition and are commonly used in nutritional supplements, fertilizers, and food technology. Industrial uses include the production of drugs, biodegradable plastics, and chiral catalysts.
Natural Amino Acids,Amino Acids Powder,Amino Acids Particles,Amino Acids Tablets
SINOCHEM PHARMACEUTICAL CO., LTD , https://www.sinochemnutrition.com