• Journal of Institute of Convergence Technology
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• v.1 no.1
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• pp.34-40
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• 2011

In this paper, a hybrid design tool combining one-dimensional(1D) lumped model and three-dimensional computational fluid dynamics(CFD) approach has been developed in order to evaluate the performance of inkjet print head and droplet control process are studied to reduce the deviations between nozzles which affect the size of the printed line for the industrial application of direct writing on printed circuit boards(PCB). 1D lumped model analysis shows that it is useful tool for evaluating performance of an inkjet head by varying the design parameters. The differences in ejected volume and droplet velocity between analytical and experimental result are within 12%. Time sequence of droplet generation is verified by the comparison between 3D analysis result and photographic images acquired by stroboscopic technique. In addition, by applying DPN process, velocity and volume uniformity between nozzles is dramatically improved that the tolerance achieved by the piezoelectric inkjet printhead across the 64 nozzles is 5 to 8%. A printed line pattern is successfully obtained using the fabricated inkjet print head and droplet calibration system.

• JSTS:Journal of Semiconductor Technology and Science
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• v.8 no.2
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• pp.121-127
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• 2008

This paper presents design and fabrication of optimized geometry structure of electrostatic inkjet head. In order to verify effect of geometry shape, we simulate electric field intensity according to the head structure. The electric field strength increases linearly with increasing height of the micro nozzle. As the nozzle diameter decreases, the electric field along the periphery of the meniscus can be more concentrated. We design and fabricate the electrostatic inkjet heads, hole type and pole type, with optimized structure. It was fabricated using thick-thermal oxidation and silicon micromachining technique such as the deep reactive ion etching (DRIE) and chemical wet etching process. It is verified experimentally that the use of the MEMS inkjet head allows a stable and sustainable micro-dripping mode of droplet ejection. A stable micro dripping mode of ejection is observed under the voltages 2.5 kV and droplet diameter is $10\;{\mu}m$.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.965-966
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• 2008

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1947-1950
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• 2008

Printing technology is a very useful method in the several process of industrial fabrication due to noncontact and fast pattern generation. To make micro pattern, we investigate the electrostatic induced inkjet printer head for micro droplet generation and drop-on-demand jetting. In order to achieve the drop-on-demand micro droplet ejection by the electrostatic induced inkjet printer head, the pulsed DC voltage is supplied. In order to find optimal pulse conditions, we tested jetting performance for various bias and pulse voltages for drop-on-demand ejection. In this result, we have successful drop-on-demand operation and micro patterning. Therefore, our novel electrostatic induced inkjet head printing system will be applied industrial area comparing conventional printing technology.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.10a
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• pp.757-758
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• 2009

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.79-80
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.587-588
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• 2006

Drop-on-Demand (DOD) inkjet printing technology, especially piezo-typed, has been paid attention by industries due to its inherent nature of unbeatable material usage and low cost manufacturing cost. Despite of these key advantages over any other competing manufacturing technologies, the primary disadvantage has been considered as its limited capability to produce fine resolution patterns with a commercially available DOD inkjet print head. Although the main effort has been focused on the production of a DOD inkjet print head with smaller nozzles to overcome this challenging issue, an alternative approach could be taken and it would enable to expand the employment of DOD inkjet printing technology to applications requiring fine patterns further more.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.4
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• pp.342-347
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• 2008

Bridge circuit was developed such that the pressure wave in the inkjet can be measured. In order to test the circuit, the microfab single ejector was used. For the experiment, the head was filled with nano silver ink (20wt%). In order to generate waveform voltage for jetting signal, the Agilent 33120 was used in order to generate arbitrary waveform. For the driver, PZD 350 from TREK was used in order to amplify the waveform. Experimental results show that the designed circuit can effectively detect the pressure wave in the inkjet head.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.11a
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• pp.719-720
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• 2008

• Journal of the Korean Society for Precision Engineering
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• v.28 no.1
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• pp.73-79
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• 2011

Inkjet printhead may have a lot of nozzles to increase productivity as a manufacturing tool. So, the uniformity of jetting performance among a lot of nozzles has been one of the key issues in inkjet technology In this study, we investigated the cross-talk effect which should be reduced for uniform jetting performance among a lot of nozzles. Due to the cross-talk, the jetting performance of a nozzle can be affected when neighboring nozzles are firing. For experimental study, we used commercial inkjet head SE-128 from Dimatix. To understand the cross-talk effect of SE-128 head, we measured the change in jetting speed of a nozzle when neighboring nozzles are jetting. The measured jetting speed was compared to the case of one nozzle jetting. Also, we used laser vibrometer to measure change in pressure wave due to cross-talk. As a result of the cross-talk, the jetting speed can become faster or sometimes slower depending on firing nozzle location. If the all nozzle are jetting, the jetting speed of a nozzle became slower because the pressure wave for jetting is reduced.