• KIPS Transactions on Software and Data Engineering
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• v.2 no.12
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• pp.889-898
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• 2013

Due to the popularization of high-performance capturing equipments and the emergence of powerful image-editing softwares, it is easy to make high-quality counterfeit money. However, the probability of detecting counterfeit money to the general public is extremely low and the detection device is expensive. In this paper, a counterfeit money detection algorithm using a general purpose scanner and computer system is proposed. First, the printing features of color printers are calculated using morphological operations and gray-level co-occurrence matrix. Then, these features are used to train a support vector machine classifier. This trained classifier is applied for identifying either original or counterfeit money. In the experiment, we measured the detection rate between the original and counterfeit money. Also, the printing source was identified. The proposed algorithm was compared with the algorithm using wiener filter to identify color printing source. The accuracy for identifying counterfeit money was 91.92%. The accuracy for identifying the printing source was over 94.5%. The results support that the proposed algorithm performs better than previous researches.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.829-836
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• 2000

High performance laser printer requires high speed scanning motor, which can operate up to 40,000 rpm. However, development of high speed scanning motor has been restricted due to the practical problems such as use of high speed bearing, compact circuit design and high cost. In this study, we designed a high speed scanner motor for use on laser scanning unit and discussed some design principles including the reduction method of cogging torque of the motor, development of hemispherical aerodynamic bearing, windage loss estimation, and operating circuit design to reduce noise.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.2
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• pp.90-95
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• 2001

f-$\theta$len is one of the important parts in Laser Scanning Unit because it affects on the optical performance of Laser Scanning Unit dominantly. It is necessary to find out the relationship between the surface profile error of f-$\theta$lens and the beam profile focusing on the Organic Photo Conductive drum in order to analysis the beam profile problems such as appearance of side lobe and expansion of center lobe. In this research, a simulation process which relates the surface profile characteristics to the beam profile has been developed by CODE V. The simulated beam profile also have been compared with the measurement results.

• The Optical Journal
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• s.128
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• pp.17-20
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• 2010

장비 효율화와 복합기와 프린터의 적어진 가격 격차에 따라 전체 출력기기 시장에서 복합기의 비중은 지속적으로 높아져 2009년 73%에서 2012년 82%까지 늘어날 전망이다. 특히 A3 컬러 디지털 복합기의 성장폭이 매우 클 전망이다. 전년 대비 약 40% 늘어난 규모의 시장이 형성될 것으로 보여 A4 레이저 시장이 11% 성장하는 한편, A3 레이저 시장은 무려 21% 이상의 두배 가까운 성장률을 보일 것으로 전망된다. 전 세계적으로 A4 성장률이 높은 반면, 한국 시장의 경우 금액기준 A4는 4.7%, A3는 7.1%의 연평균 성장률을 보이며 A3 시장이 시장 성장을 주도할 것으로 예측된다.

• Journal of the Microelectronics and Packaging Society
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• v.26 no.1
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• pp.17-21
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• 2019

In this paper, a high precision straightness measurement system has been developed at low cost using a visible laser and CMOS image sensor. CMOS image sensor detected optical image and the variation of straightness was calculated by image processing. We have observed that the error of the developed straightness measurement system was 0.9% when a distance of 3m between laser and image sensor. And it can be applied to 3D printer and any other areas.

• Journal of Korean Ophthalmic Optics Society
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• v.3 no.1
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• pp.181-188
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• 1998

In order to examine the legibility of the Hangul letters which is a syllabic, the three kind of visual charts were made of the ninety eight($14{\times}7$) Hangul Gothic type letters by the laser printer. These Hangul letters were constructed with the 13 consonant letters which are 'ㄱ, ㄴ, ㄷ, ㄹ, ㅁ, ㅂ, ㅅ, ㅇ, ㅈ, ㅋ, ㅌ, ㅍ, ㅎ', and the 6 vowel letters which are 'ㅏ, ㅓ, ㅗ, ㅜ, ㅡ, ㅣ'. The two examination methods were used, One is the discriminating the letters on the visual chart by men having 1.5 visual acuity. The other is the using the laser printer's resolution. Obtained data by these examination methods are the minimum readable size values of the letters and the maximum readable distance values from the reader to the objects. From these data the relative legibility of the Hangul letters were calculated, where the letter ㄱ was chosen for the standard. This resultant data were analyzed. In this result, the mean legibility of these Hangul letters descended in the order of 'ㄱ, ㄴ, ㅅ, ㄷ, ㅈ, ㅇ, ㅁ, ㅋ, ㅌ, ㅍ, ㅎ' Which are the consonant letters being in these letters. And the mean legibility descended in 'ㅣ, ㅡ, ㅏ, ㅗ, ㅓ, ㅜ' order. The mean legibility is dependent on used consonant letter more then on used vowel.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.5
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• pp.575-582
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• 2011

A cleaning blade is an attachment installed in the toner cartridge of a laser printer for removing the residual toner from an organic photo-conductive drum. There have been many studies on the performance and life of the rubber blade. We focus on optimally designing the blade shape parameters to minimize the maximum stress of the blade while satisfying design constraints on the cleaning performance and part interference. The blade is optimally designed using a design of experiments, meta-models and an optimization algorithm implemented in PIAnO (process integration, automation, and optimization), a commercial PIDO (process integration and design optimization) tool. We integrate the CAE tools necessary for the structural analysis of the cleaning blade, automate the analysis procedure, and optimize the solution using PIAnO. We decreased the maximum stress by 32.6% in comparison with that of the initial design.

• Proceedings of the KAIS Fall Conference
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• 2010.11a
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• pp.474-477
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• 2010

최근 디지털 장비의 발전에 발맞추어 고속, 고화질의 컬러 문서가 요구됨에 따라 레이저 프린터의 보급 또한 급속도로 성장하고 있는 실정이다. 토너는 고속, 고화질의 컬러 문서 인쇄에 가장 중요한 역할을 하는 것으로, 크게 분쇄법과 중합법에 의해 제조 되고 있다. 그러나 그 중 분쇄법 토너는 근본적으로 해결되지 않는 문제점들이 있다. 즉, 중합된 수지를 사용함으로 인한 단가상승과 수지와 내첨제를 용융혼합하는 과정에서의 분산의 한계성, 그리고 인쇄 품질의 좋지 않은 것이 그 대표적인 예이다. 이에 본 실험에서는 고속, 고화질의 컬러 프린터에 적합한 중합법에 의한 토너 제조시 하이드록시아파타이트가 토너 제조에 미치는 영향에 대해서 연구하였다. Ca/P의 몰비에 따라 제조된 하이드록시아파타이트가 토너의 입자형성에 크게 영향을 주었으며, 이에 따라 토너의 물성에도 영향을 주는 것으로 나타났다. 또한 pH에 따라서도 토너중합에 많은 영향을 주는 것으로 나타났다. 토너 입자 형성에 적절한 Ca/P의 몰비 및 pH가 존재 하며, 이를 최적으로 조절하면 양질의 토너를 제조 할 수 있을 것으로 판단된다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2019.07a
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• pp.395-396
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• 2019

표적 암세포 또는 마이크로미터 단위 이하의 미세 입자의 검출하기 위해 다양하게 사용되는 유세포분석기는 레이저와 같은 특정 파장의 광원 및 파장대별 선택이 가능한 필터, 고성능 광탐지기로 구성되어있다. 이 분석기는 표적물질의 광학적 산란특징에 기인하여 입상도와 크기, 농도 등의 물리적 정보제공이 가능하나, 고가이며 사용자의 요구에 따른 다양한 광원 및 필터의 선택이 제한적이라는 단점을 가지고 있다. 본 논문에서는 상용화된 마이크로컨트롤러, 발광다이오드, 광검출기와 필름형식의 광학필터를 사용하여 저가의 표적 암세포 검출기를 개발하고자 한다. 또한, 3D 프린터를 사용하여 사용자의 필요에 따른 설계변화와 이동이 용이하므로, 공간의 제약을 받지 않고 다양한 분야에 적용이 가능하다. 제안된 검출기의 광감지 수치는 세포의 농도에 따라 높은 선형성을 보였으며, 세포수량기를 사용한 결과 값과 비교하였을 때 무의미한 통계학적 차이를 보였다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.7
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• pp.701-706
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• 2015

In this study, experimental and computer simulation results are compared and analyzed. Three-dimensional (3D) fabricated matrices from an MJM 3D printer were joined with poly-acetate thermoplastic polymers using a diode laser. A power range of 5-7 W was used to irradiate the boundary of two polymers. The heated polymers flowed into the matrices of the 3D fabricated structure, and reliable mechanical joining was achieved. Computer simulation showed the temperature distribution in the polymers, and flow direction was estimated based on the flux and temperature information. It was found that the more than the minimum energy threshold was required to effectively join the polymers and that two scans at low-speed were more effective than four scans at high speed.