• Journal of KIISE:Software and Applications
• /
• v.37 no.8
• /
• pp.599-610
• /
• 2010

Color laser printers are nowadays abused to print or forge official documents and bills. Identifying color laser printers will be a step for media forensics. This paper presents a new method to identify color laser printers with printed color images. Since different printer companies use their own printing process, each of printed papers from different printers has a little different invisible noise. After the wiener-filter is used to analyze the invisible noises from each printer, we extract some features from these noises by calculating a gray level co-occurrence matrix. Then, these features are applied to train and classify the support vector machine for identifying the color laser printer. In the experiment, we use total 2,597 images from 7 color laser printers. The results prove that the presented identification method performs well using the noise features of color printed images.

• The Journal of the Korea Contents Association
• /
• v.12 no.12
• /
• pp.639-646
• /
• 2012

To analyzed the shape of Yellow Dots which appeared on the paper printed HP color laser printer, and analyzed the characteristic of Yellow Dots according to time, month, year and same printers. As a result, documents that printed in same printers had an identical Yellow Dots's shapes according to time, month, year. It was presupposed that was not embedded time and date information in HP Color LaserJet printers against Xerox, and printers which have different serial number had similar shapes but it was not identical Yellow Dots. Finally, it was found to be identical patterns in Yellow Dots of HP Color LaserJet printers used analysis. Depending on the results, it could understand HP's pattern. In the future, it will decipher patterns of Yellow Dots which have other informations to include other printer manufacturer.

• Particle and aerosol research
• /
• v.6 no.3
• /
• pp.123-129
• /
• 2010

As the indoor activity increases in recent years, the indoor air quality becomes more important. One of the major contaminants in office space is the copy machines and the laser based printers. These devices usually emit nano-particles and chemical species that may give some health effect. The amount of particles generated by the printers and copy machines depend on printer models, printing speed, toners, papers, humidity and so on. To evaluate the emission rate of nano-particles from Laser Printers, the mass concentration measurement method has been used (BAM, 2004). However, the mass concentration measurement method for nano-particles is tedious and time consuming. Therefore, for the development of a new nano-particle counting method, the nano-particle emission characteristics and size distributions are evaluated.

• Journal of Power Electronics
• /
• v.6 no.2
• /
• pp.178-185
• /
• 2006

Recently, the demand for the development of high quality and high-speed laser printers and efficient power utilization has required. Among complicated electro-mechanic devices in laser printers, the toner-fusing unit consumes above 90[%] of all electrical energy needed for printing devices. Therefore, the development of a more effective energy-saving toner fusing process becomes a significant task in great demand. Generally, there are several ways to implement a fusing unit. Among them this paper presents a new induction heating method. The proposed induction heating method enables the increase of coupling coefficient between heating coil and heat roller which also increases total energy transfer efficiency. Therefore, the proposed IH (Induction Heating) inverter system provides very fast W.U.T. (Warm UP Time) as well as higher efficiency. Through experimental results, the proposed control system is verified.

• The KIPS Transactions:PartB
• /
• v.17B no.3
• /
• pp.197-206
• /
• 2010

High-quality and low-price digital printing devices are nowadays abused to print or forge official documents and bills. Identifying color laser printers will be a step for media forensics. This paper presents a new method to identify color laser printers with printed color images. Since different printer companies use different manufactural systems, printed documents from different printers have little difference in visual. Analyzing this artifact, we can identify the color laser printers. First, high-frequency components of images are extracted from original images with discrete wavelet transform. After calculating the gray-level co-occurrence matrix of the components, we extract some statistical features. Then, these features are applied to train and classify the support vector machine for identifying the color laser printer. In the experiment, total 2,597 images of 7 printers (HP, Canon, Xerox DCC400, Xerox DCC450, Xerox DCC5560, Xerox DCC6540, Konica), are tested to classify the color laser printer. The results prove that the presented identification method performs well with 96.9% accuracy.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2016.10a
• /
• pp.735-737
• /
• 2016

In this paper, we conducted a test of the 3D printer injection method and LSU (Laser Scanning Unit) feature a fusion of the polygon mirror scanning system that is the core mechanism operation for 3D printers for office laser printers SLA system. These tests ensure that the laser was operating and control well was confirmed that a certain point is output to the X-axis by means of a laser module and a polygon mirror. And confirmed after the F-theta lens is incident on the fixed laser power of the beam, and correction according to the correction beam on the mirror reflection was confirmed jineunji the focus according to the Z-axis upper plate.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2014.10a
• /
• pp.138-140
• /
• 2014

The image quality of the color laser printer is highly related with the motion quality of actuators. However, the high precision system requires high production costs in general. The proposed design method in this paper improves image quality without increasing production costs. Using the synchronization method, time gap between exposure and transfer in organic photo conductive (OPC) drum and the period of driving gear revolution are synchronized. The proposed method is verified by computer simulations and experiment, and showed by printed images.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2008.06a
• /
• pp.651-652
• /
• 2008

• Korean Journal of Construction Engineering and Management
• /
• v.21 no.2
• /
• pp.3-14
• /
• 2020

This study reviews and comparatively analyzes existing classification systems for 3D concrete printers to propose a classification system for 3D concrete printers. Several classifications for existing 3D printers have been proposed and used in the market. Nevertheless, quite a few of the printer types such as fused deposition modeling (FDM) and selective laser melting (SLM) are not suitable for characterizing 3D concrete printers. To derive the properties that distinguish one 3D concrete printer type from the others, this study reviews existing 3D concrete printers and comparatively analyzes the properties of 3D concrete printers identified in previous studies. The results show that existing classifications do not reflect the states-of-the-art of 3D concrete printers, the classification terms are ambiguous, and the entire printing processes are not considered. A new classification system was proposed based on the essential properties of the 3D concrete printers identified through the analysis of related work. The result of this study can be used as a basis for classifying commercial 3D concrete printers as well as studies related to 3D concrete printers.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.21 no.6
• /
• pp.1225-1230
• /
• 2017

3D printers have been growing mainly in industrial use, but the recent growth of the personal 3D printer market advanced through economic effects and cost reduction due to technological development. However, current 3D personal printers are very low in customer satisfaction on the limitations of molding speed, size, and precision. In this paper, we propose SLA 3D printer using LSU to overcome the technical limitation of personal 3D printer. In order to verify the operation of the scanning mechanism which is responsible for core functions, the movement of molding board using stepping motor and laser output test was conducted. These tests ensure that the laser was operating and control well was confirmed that a certain point is output to the X-axis by means of a laser module and a polygon mirror. 3D printers which are proposed to improve the accuracy and manufacturing speed is expected to replace the traditional low-budget 3D printer.