Water-based ink
It is commonly used on apertured and non-coated substrates such as paperboard and paper, and is often used most often in the direct mail product printing and other commercial printing markets. It can also be divided into pigment type and dye type. Since the pigment is insoluble in water, it will precipitate. Therefore, the pigment particles must be very finely sculpted. To be as small as 30μm or less, there will be better jet printing effect, otherwise the high resolution will be used. Can cause obstruction. The pigment's weather resistance, lightfastness, wash fastness, and fastness are all very good. The advantage of the dye is that there is no problem in solubility, and there are many types of colors, and the brightness is good, but the fastness is poor.
2. Oil-based ink
It is best suited for printing on perforated materials because it is dried by absorption. They are formulated with vegetable oils or mineral oils, which are particularly useful in the field of cardboard packaging; they are not suitable for use in closed office spaces because Produce air pollution.
The colorants used can be divided into two types: pigment type and dye type. Oil-soluble type inks are characterized by fast drying, so they are more commonly used in the industry.
3. Solvent-based ink
It is widely used, from signage printing to bar code printing to outdoor advertising. The use of this kind of ink has high economic efficiency, quick drying and can be printed on a variety of materials, especially for the printing of non-coating materials such as vinyl, wire mesh , glass, paper, etc.
4.UV/EB thermosetting ink
The ink is suitable for printing on a variety of soft and rigid substrates such as corrugated cardboard and metal foils. UV/EB inks cure faster and have greater durability under UV light. Ideal for DOD applications such as retail display advertising, calling cards, credit cards and frequently used shopping cards.
In addition to the classification of the connection materials, in practice, there are some other classification methods: According to the color materials, divided into organic dye inks, polymeric dye inks and pigment inks; if used according to the ink The different drying mechanisms can be divided into volatile inks and polymeric inks. Aqueous and non-aqueous inks use water or other solvents as the binder. Drying is accomplished by the penetration and absorption of the ink by the substrate. If ordinary copy paper or flatbed paper is used, the ink and its binder are absorbed together by the substrate. This absorption will reduce the color density and sharpness of the print. Thermosetting ink means that the ink is a solid at room temperature. When it is ejected from a nozzle, it is a hot melt liquid and rapidly solidifies when it reaches the surface of the substrate. This rapid solidification feature prevents the ink from spreading or penetrating into the interior of the substrate. , ensure the printing quality.
Second, choose the right ink
1. Ink supplied by ink jet digital printer manufacturers
In the actual production process, producers generally choose the ink provided by ink jet equipment providers. In fact, this has both advantages and disadvantages. Of course, different digital printing opportunities use different technical methods such as continuous inkjet (CIJ) and drop-on-demand (DOD). The two inks are not interchangeable because the two technologies are completely different. The CIJ technique refers to the continuous generation of ink droplets that form an ink droplet stream that is imaged through a deflection plate; whereas DOD technology is a digital signal that is generated on demand. Some ink droplets, rather than an ink stream, change the ink at will, causing ink mess. Therefore, in the production, the premise of the maximum effect of the printing press is to have a full understanding of the ink used, which needs to consider the impact of a variety of factors.
2. Selection of printing media and ink
For inkjet printing, how to control the printing effect on different printing media, it is necessary to analyze the properties of the substrate. Taking paper as an example, due to the thermodynamic interaction between paper and ink, the capillary action of the paper, and the spread of the ink chemical composition, etc., the absorption of ink components by the paper is caused, that is, the ink penetration. Among them, the capillary action of paper is the main cause of ink penetration. Because the paper itself is a porous water-permeable structure, the ink is easily diffused inside the paper. With the increasing development of the paper surface coating process, the different distribution of the ink inside the paper leads to different ink penetration effects. Therefore, the paper for inkjet printing requires paper with a smooth surface and a certain degree of sizing. The sprayed ink evaporates and dries. The dots of ink are circular, the printed characters are clear and the graphics are beautiful. Color inkjet printing paper, preferably with a thin layer of transparent coating on the surface, can absorb ink quickly and avoid light scattering.
Inkjet inks can be printed on a variety of substrates, which is a big advantage, such as fiber, wallpaper, glass, plastic, metal foil and plastic film, and of course, on various types of paper. Knowing which type of ink-jet technology is suitable is just one aspect of the problem. Also, is the substrate material coated or uncoated? Is the substrate material porous or non-porous? Printing materials absorb water or not absorb water? How is the effect of ink on the surface of the substrate? All these will be related to the formulation of print job plans, increase production efficiency, and ultimately improve the return on investment.