Inkjet printing is an excellent printing technique and an attractive alternative to conventional technologies for the production of flexible, low-cost microelectronic devices. Among many parameters that have a significant impact on the correctness of the printing process, the most important is ink viscosity. During the printing process, the ink is influenced by different strains and forces, which significantly change the printing results. The authors present a model and calculations referring to the shear rate of ink in an inkjet printer nozzle. Supporting experiments were conducted, proving the model assumptions for two different ink formulations: initial ink and with the addition of a dispersing agent. The most important findings are summarized by the process window regime of parameters, which is much broader for the inks with a dispersing agent. Such inks exhibit preferable viscosity, better print-ability, and higher path quality with lower resistivity. Presented results allow stating that proper, stable graphene inks adjusted for inkjet technique rheology must contain modifiers such as dispersing agents to be effectively printed.

Purpose – The purpose of this paper is to present the result of research on a new fabrication technology of printed circuits board and electronics modules. The new method is based on inkjet printing technique on flexible substrates using new generations of heterophase inks. New fabrications method was used to print microwave waveguides and signal splitters as new technology demonstrators. Design/methodology/approach – A fully Inkjet printed filter was printed on a flexible, transparent Kapton foil using heterophase inks developed in Instytut Technologii Materiałów Elektronicznych (ITME) for the purpose of this research based on graphene and silver nanoparticles. Findings – A microwave module was printed using two types of Inkjet printers – PixDro LP50 with KonicaMinolta 512 printhead – and developed in an Instytut Tele- i Radiotechniczny (ITR) laboratory printer using MicroDrop a 100-μm glass nozzle printhead. Fully printed microwave circuits were evaluated by their print quality and electrical properties. Originality/value – Fully Inkjet printed microwave circuits using the heterophase graphene ink were evaluated by their print quality and electrical properties.

Organic electronics is a platform technology that enables multiple applications based on organic electronics but varied in specifications. Organic electronics is based on the combination of new materials and cost-effective, large area production processes that provide new fields of application.Organic electronic by its size, weight, flexibility and environmental friendliness electronics enables low cost production of numerous electrical components and provides for such promising fields of application as: intelligent packaging, low cost RFID, flexible solar cells, disposable diagnostic devices or games, and printed batteries [1].The paper presents results of inkjetted electronics elements on flexible and glass substrates. The investigations was target on characterizing shape, surface and geometry of printed structures. Variety of substrates were investigated, within some, low cost, non specialized substrate, design for other purposes than organic electronic.Organic electronics can be fabricated using well known printing techniques, out of which, roll-to-roll techniques are the most desirable. They require, however, expensive tools accompanied with, high cost test runs. Hence, they are inconvenient for research and development laboratory tests. For this reason, small companies and research institutes are more interested in InkJet technology, perfect for small scale production and prototyping. Inkjet printers do not require tools or process changes for fabricating new set of elements. They lower the cost of prototype fabrication by printing from graphic bitmap files straight to the substrates. This makes InkJet printing the leader of organic electronics fabrication technologies. For this reason, the investigation of the inkjet printing process is crucial for the fabrication of printing electronic issue. PRINTED ELECTRONIC MANUFACTURING.In Tele-and Radio Research Inst tute investigations and tests have been made on self built InkJet printer. Printer is based on MicroDrop piezo-electric printing head, with nozzle diameter of 50 μm, and drops volume from 35 to 55 pico litters. The pH of ink is to be in range 1 to 12, and the viscosity in range 1-15 cP [2]. This allows to test high variety of commercial inks and new inks produced by companies and other research institutes. The printer scheme is shown in figure 1.

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