• 대한전자공학회논문지
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• 제24권2호
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• pp.331-337
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• 1987

This is paper, we represent the laser printing system as the new technique in computer output printing. Laser printer, which can process a lot of information for high speed and high resolution, has been designed and realized in our design performance. Optical signal processing and data processing technique are described. Also the requirements for the optical components and their implementations are discussed. The arbitrary patterns, Korean and Chinese characters are given as printed outputs actually.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.2160-2163
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• 2005

Solid freeform fabrication (SFF) technology plays a major role in industry and represents a reasonable percentage of industrial rapid prototyping/tooling/manufacturing (RP/RT/RM) development applications. However, SFF technology still has long way to progress to achieve satisfactory process speed, surface finish and overall quality improvement of its application. Today, three dimensional printing (3DP) technique that is one of SFF technology is receiving many interests, and is applied by various fields. It can fabricate three dimensional objects of solid freeform with high speed and low cost using ink jet printing technology. However, need long curing time after manufacture completion. And it must do post-processing process necessarily to heighten strength of objects because strength of fabricated objects is very weak. Therefore, in this study, we proposed an improved 3DP process that can solve problems of conventional 3DP process. The general 3DP process is method to spout binder simply through printer head on powder, but proposed process is method to cure jetted UV resin by UV lamp after jet UV resin using printhead on powder. The hardening of resin is achieved strongly at early time by UV lamp in proposed method. So, the proposed process can fabricate three dimensional objects with high speed without any post-processing.

• 한국기계가공학회지
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• 제16권6호
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• pp.101-108
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• 2017

Recently, the patent rights for 3D printing technology have expired, while 3D printers with RP (Rapid Prototyping or Additive Manufacturing) and 3D printing technologies are receiving attention. In particular, the development of 3D printers is rapid in Korea, thanks to the increasing sales and popularity of FDM (Fused Deposition Modeling or Fused Filament Fabrication) 3D printers. However, the quality and productivity of the FDM 3D Printer are not good, so customers prefer the DLP (Digital Light Processing) method to avoid these shortcomings. The DLP method has high quality and productivity. However, because of the stereolithography equipment, it has few studies compared to optimal values for elements then FDM 3D printing study. In this study, to find the optimal conditions for 3D printing with the DLP method, the aim is to obtain the optimal values (strength, final time, quality) by changing the light exposure time, layer thickness, and z-axis speed.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2007년도 추계학술대회
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• pp.128-133
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• 2007

An electrostatic inkjet head can be used for manufacturing processes of large display systems and printed circuit boards (PCB) as well as inkjet printers because an electrostatic field provides an external force which can be manipulated to control sizes of droplets. The existing printing methods such as thermal bubble and piezo inkjet heads have shown difficulties to control the ejection of the droplets for printing applications. Thus, the new inkjet head has been proposed using the electrostatic force. A numerical analysis has been performed to calculate the intensity of the electrostatic field using the Maxwell's equation. Also, experiments have been carried out to investigate the droplet movement using a downward capillary with outside diameter of $500{\mu}m$. Gravity, surface tension, and electrostatic force have been analyzed with high voltages for a drop-on-demand ejection. It has been observed that the droplet size decreases and the frequency of the droplet formation and the velocity of the droplet ejection increase with increasing the intensity of the electrostatic field using high-speed camera.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2003년도 추계학술발표논문집 (상)
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• pp.393-396
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• 2003

고속프린터 시장의 지속적인 성장에도 불구하고 국내는 물론 국외에서도 고속프린터의 구조와 속도에 대한 연구는 매우 미미하게 이루어지고 있다. 특히, 우리나라가 이미 중 저속프린터 시장의 국제경쟁력을 확보하고 있는 상황에서 고속프린터에 대한 연구 활동을 촉진하여야한다. 이를 통하여 우수한 성과를 도출하고 노-하우를 축적함으로써 경쟁력을 보다 강화하고 나아가 세계시장을 주도할 필요가 있다. 이에 본 논문에서는 고속프린터의 기본적인 구조를 제시하고 각 장치가 프린터의 전체적인 성능에 미치는 영향을 분석하여 179.104 PPM의 성능을 보이는 고속프린터의 구조를 제안하였다.

• 전자공학회논문지S
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• 제35S권1호
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• pp.105-113
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• 1998

A new image processor is implemented for high-speed digital copiers and facsimiles. The imgage processor performs CCD and CIS interface, pre-processing, enlargement andreduction of gray level image, and various halftoning algorithms. Implemented halftoning algorithms are simple thresholding, fuzzy based mixed mode thresholding, dithering, and edge enhanced error diffusion. The result of binarization is transferred to a printer with serial or paralel output ports. Line by line pipelined data prodessing architecture is employed with time sharing access of the external memory. In receiving mode, it converts the resolution of received binary image for compatibility with conventional facsimile. In copy mode, a line of A3 paper with 400 dpi is processed with in 2.5 ms. The prototype of image processor was implemented usig Laser Programmable Gate Array (LPGA) with 0.8.mu.m technology.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 ICEIC The International Conference on Electronics Informations and Communications
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• pp.122-127
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• 2004

The color gamut mapping method that is used for enhancing the color reproduction quality between PC monitor and printer devices is adopted for display quality enhancement. The high definition display devices operate at the clock speed of around $70\;MHz\;\sim\;150\;MHz$ and permit several nano seconds for real-time processing. Thus, the concept of three-dimensional reduced resolution look-up table is used. The required hardware can be greatly reduced by look-up table resolution adjustment. The proposed hardware architecture is successfully implemented in ASIC and also successfully adopted in display quality enhancement purposes.

• 한국레이저가공학회지
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• 제17권4호
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• pp.14-19
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• 2014

Laser beam was applied on the boundary of the polyurethane and biodegradable polyacetate polymers. The distributed laser passed through the polyurethane layer and heated the polyacetate layer, then the soften acetate was squeezed thorough the 1mm square slots of polyurethane for the mechanical joining. The surface roughness ranging between $0.28{\mu}m$ and $3.06{\mu}m$ had almost no effect on joining strength, but the optical properties of HD (High Definition) and UHD (Ultra High Definition) mode affected laser beam transmittance. The optimum laser power was found to be between 8watt and 10watt with 500mm/min of scanning speed. The joining boundary was characterized by optical and SEM analysis. Based on the experiment and characterization results, the laser energy was effective for the polymer joining and efficiency of joining.

• 대한전자공학회논문지SP
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• 제41권5호
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• pp.225-233
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• 2004

본 논문에서는 기존에 PC 모니터와 프린터 사이의 색 재현성 향상을 위해서 사용되던 색역폭 매핑 방법을 디스플레이 장치에 적용하기 위한 실시간 색역폭 매핑 방법을 제시하였다. 다양한 디스플레이 장치가 개발됨에 따라서 각 디스플레이 별로 색 재현성의 차이가 발생하고 있으며 기존의 색역폭 매핑 방법을 디지털 TV의 디스플레이 장치에 적용하기 위해서는 수 나노초 단위의 처리 속도가 필요하다. 이를 위하여 본 논문에서는 절감 3차원 룩업 테이블(three-dimensional reduced resolution look-up table)의 하드웨어 구조를 제안하고 이를 이용하여 색역폭 매핑을 실시간으로 수행하는 방법을 제공한다. 제안된 하드웨어 구조는 먼저 simulation을 통하여 타당성을 검증하였으며 이후 FPGA와 ASIC으로 구현되어 디지털 TV의 디스플레이 장치의 화질 개선에 성공적으로 적용되었다.

• 한국기계가공학회지
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• 제21권2호
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• pp.137-143
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• 2022

Composite materials, being light-weight and of high mechanical strength, are increasingly used in various industries such as the aerospace, automobile, sporting-goods manufacturing, and ship-building industries. Recently, manufacturing of composite materials using 3D printers has increased. 3D-printed composite materials are made in free-form and adapted for end-use by adjusting the fiber content and orientation. However, research on the machining of 3D printed composite materials is limited. The aim of this study is to develop a machine learning method to select machining conditions for machining of 3D-printed composite materials. The composite material was composed of Onyx and carbon fibers and stacked sequentially. The experiments were performed using the following machining conditions: spindle speed, feed rate, depth of cut, and machining direction. Cutting forces of the different machining conditions were measured by milling the composite materials. PCA, a method of machine learning, was developed to select the machining conditions and will be used in subsequent experiments under various machining conditions.