Today, there are a number of low resolution circuits and electronic devices that can be produced by printing. This field is opening up a wide array of novel applications that could be commercially and economically feasible in the future. The key is to make it efficient and affordable. Printing offers unique features including:  

1) Customization in volume production • Short time cycle from design to manufacturing • Fast manufacturing runs • Reduced logistics costs 2) Production advantages • Ergonomic user interface solutions • Environmentally friendly 3) Applicability in novel products • Flexible structures • Low end integrated electronics [6]  

Printing may be the optimum process for production of many plastic based electronic circuits, large area devices, and flexible electronics. Printing enables the production of disposable, thin and wearable electronics. Some of the interesting end applications for printable electronics are identification, antennas, displays, RFIDs, sensors, batteries, security devices and quality indicators. Among the unique characteristics of printable electronics are that it has a low environmental impact, low cost, and may be the optimal process for production of disposable devices, single use devices, smart packaging, flexible electronics and large area devices [7].  

Techniques and processes that have been explored in regard to their utility in printed electronics are: ink-jet printing, screen printing, flexography, lithography, spray printing, stamping etc. The majority of the work in this area has involved ink-jet [8] and screenprinting technologies [9]. The major high volume printing processes currently in use are offset lithography and flexography [3], [5], [10]. Printing of conductive inks to fabricate circuits [5], LEDs [11], sensors [12], microwave integrated circuits (MIC) [13], radio frequency circulator components on a wide range of flexible materials [14] etc. have been reported using offset lithography. Conductors, resistors, anodes/emitting layers, OLEDs [15] have been fabricated using flexography and gravure printing. 

Key requirements for printable electronics are: need for functional fluid materials to build logics, a suitable high-speed and large volume printing process that makes ease of production and low cost feasible and adaptation to the process to print electronics 

The key benefit of printed electronics is that it offers the possibility of using electronics in applications where the cost of silicon would make it impossible or the brittleness of silicon would make it inadequate [16]. In fact, this can be looked upon not as plasticbased microelectronics replacing the silicon industry but as building a different low-end commercial application industry. When conventional components are too big to be included in the silicon chip, it becomes uneconomical to increase chip sizes. Separate components add cost and failure modes. For such applications, printing seems to be the appropriate technology to explore [17].  

Utility of High Volume Printing Processes in Printable Electronics 

Extensive research has been carried out in printable electronics in ink-jet and screenprinting technologies.  However, screen and ink-jet printing are relatively slow, limiting their productivity and use in high volume manufacturing [8]. A number of “soft lithographic” techniques have been used to make devices like transistors, RFID tags, wearable electronics and other novel applications [18], [19]. They too are however slow and have a limited production volume. Some of the major advantages of high volume printing processes are: 

• High volume, high speed 

• Additivity 

• Substrate latitude (including flexible substrates) 

• Large area printing 

• Demonstrated repeatability  

• Negligible waste