Inkjet substrate

However, an exact match of the surface tension of the inks and substrate means that a particular set of inks will be suitable for printing on narrow span of substrates — only the substrates matching the surface tension of the inks. Different substrates will require a different set of inks. Furthermore, even a full match of surface tensions (of both inks and surface) will not eliminate the issues which are related to porous substrates — including the most commonly used substrates — Paper In order to enable high quality inkjet printing on paper, a whole set of new products was introduced to the market — "inkjet paper" or "inkjet substrate". 

Dot shape on inkjet substrate spherical dot with sharp edges... 

Several studies were recently carried out to better understand the mechanisms which dominate the behavior of an ink droplet on top of plain paper or inkjet paper and to enable better design of advanced inkjet substrates. A detailed study about the spreading on and penetration into thin, permeable print media and its application to inkjet printing was recently published. Adetailed review of the interaction... 

The "Inkjet Substrate" approach to enhancing print quality was characterized by a thin, highly absorptive layer, which physically absorbs... 

DNA arrays are fabricated by immobilizing the complementary DNA (cDNA) onto a solid substrate such as silicon, nylon or glass. This can be achieved by robotic printing of polymerase chain reaction (PCR) products (also known as direct-deposition approach), photolithographical synthesis of complementary oligonucleotides or piezoelectric inkjet printing of PCR products (also known as indirect-deposition approach). 

Nanoparticles can be deposited onto a substrate by spin coating or inkjet printing a colloidal solution and can be sintered into a continuous conductive film during the subsequent annealing step. Coalescence of individual... 

Inkjet printing as its name implies is a printing method in which a jet of ink is fired, in the form of extremely small droplets, onto a receiving medium. " It is a primary printing technology as the image is printed directly onto the substrate without any intermediate steps. The ink can be supplied in either a continuous manner or inter-... 

Drop-on-demand (DOD) inkjet is the method that is universally adopted in the printers used in the home and the office environments. It takes its generic name from the fact that ink is delivered from the ink head directly to the substrate only as demanded by the printing information supplied by the software. 

The TFT fabrication process on glass substrates starts with 100 nm of Cr for the gate metal, and is followed by a PECVD 200 nm thick Si3N4 dielectric with a 30 nm thick SiC>2 surface layer. The source drain metal is Cr/Au. Each of these layers is patterned using printed wax masks and chemical etching, steps a to d in Fig. 11.8. The surface is modified with a solution deposition of a self-assembled monolayer of octyltrichlorosilane (OTS-8) before inkjet printing deposition of the semiconductor. It has been shown that the OTS-8 layer affects the structural order of PQT-12 in thin films, improving the performance of the TFT [23]. Encapsulation and possibly other subsequent layers may be needed on the TFT, but these are not discussed here. 

Figure 12.9 shows the output and transfer characteristics of a state-of-the-art, polymer FET fabricated using the Plastic Logic direct-write manufacturing process (L = 10 pm). No encapsulation of the TFT is present other than what is naturally provided by the presence of the PET substrate on the bottom and an inkjet printed silver gate electrode on the top. The device exhibits a field-effect mobility of 0.04 cm2 V 1 s 1 and ON-OFF current ratio of 5 x 10s. The threshold potential is Vt = 5-6 V. These basic TFT performance values can be achieved consistently in a manufacturing environment, and are sufficient to drive a 100 dpi electronic paper display with A5 size. 

Surface treatments are often necessary for aesthetic and performance reasons. This can involve printing or lacquering, using both solvent and non-solvent based inks, which are applied to the surface using rollers, pads, silk screen, inkjet or lasers. Waterborne coatings are environmentally more desirable and silicone surfactants are claimed to give the best performance to improve substrate wetting (456). 

---