In this paper, the failure mechanisms of the thermal inkjet thin-film resistors are recognized. Additionally, designs of resistors to overcome these mechanisms are suggested and tested by simulation and experiment. The resulting resistors are shown to have improved lifetimes, spanning an order of magnitude up to 2 × 109 pulses. The thermal failure mechanisms were defined according to the electric field magnitude in three critical points—the resistor center, the resistor–conductor edge, and the resistor thermal “hot spots”. Lowering the thermal gradients between these points will lead to the improved lifetime of the resistors. Using MATLAB PDE simulations, various resistors shapes, with different electric field ratios in the hot spots, were designed and manufactured on an 8″ silicon wafer. A series of lifetime experiments were conducted on the resistors, and a strong relation between the shape and the lifetime of the resistor was found. These results have immediate ramifications regarding the different printing apparatuses which function with thermal inkjet technology, allowing the commercial production of larger thermal printheads with high MTBF rate. Such heads may fit fast and large 3D printers.

Three-dimensional (3D) printing is a fast-developing technology these days. However, 3D printing of a model takes many hours. Therefore, the enlargement of the printhead and the increase of the printing speed are important to this technology. In order to enable the enlargement of the printhead a different approach and design are suggested and tested experimentally. The printhead is divided into small segments; each one is autonomous, and not fluid-connected to the neighboring segment. Each segment contains a micro reservoir and few nozzles. The segments are manufactured together in close proximity to each other on the same substrate enabling area coverage. A segmented printhead based on this approach was built and tested. The micro reservoir ink-filling method and operation of the segments were experimentally proven. Ink drops were obtained and the lifetime of the resistors was measured. Electrical characteristics of power and energy for proper operation were obtained. A 3D model printed according to the suggested approach can be completed in less than a minute.