Toner Cloud Generation and its Supply over the Width of a Printing Area

Toner cloud generation along with controlling its movement is one of the important parameters in the development of digital printing by the toner cloud beam technique. In the experimental set-up for toner cloud generation, the conductive toner particles were sprayed at the center of a wide chamber-shaped dented electrode as the lower electrode was placed parallel with the upper electrode, leaving a small gap between them using two insulating sheets. An electrical, field was applied between the two electrodes. The toner moved up and down between the two electrodes by electrostatic force, forming the toner cloud, which propagated to both ends of the dented electrode. This research studies the toner cloud generation conditions using the wide chamber-shaped dented electrode, the slope of the nesa glass, and the slope of the system as the influencing factors that governed toner cloud generation and its movement. An increase in the applied voltage led to a faster toner cloud speed. When a greater amount of toner was applied into the dented electrode, a faster toner cloud movement was obtained. On the other hand, the toner cloud speed decreased when increasing the depth of the dented electrode. An increase of the slope of nesa glass increased the toner cloud speed. However, the toner cloud speed was not significant to the system when the slope was between 0 and 5 degrees. It was also found that the width of toner cloud decreased when the applied voltage increased. Furthermore, the two overlapped cone-shaped dented electrodes could be used for generating the toner transport to the printing system. This research also explains the possible phenomena for toner cloud generation and performance.     

Toner Cloud Generation and its Supply over the Width of a Printing Area

Toner cloud generation along with controlling its movement is one of the important parameters in the development of digital printing by the toner cloud beam technique. In the experimental set-up for toner cloud generation, the conductive toner particles were sprayed at the center of a wide chamber-shaped dented electrode as the lower electrode was placed parallel with the upper electrode, leaving a small gap between them using two insulating sheets. An electrical, field was applied between the two electrodes. The toner moved up and down between the two electrodes by electrostatic force, forming the toner cloud, which propagated to both ends of the dented electrode. This research studies the toner cloud generation conditions using the wide chamber-shaped dented electrode, the slope of the nesa glass, and the slope of the system as the influencing factors that governed toner cloud generation and its movement. An increase in the applied voltage led to a faster toner cloud speed. When a greater amount of toner was applied into the dented electrode, a faster toner cloud movement was obtained. On the other hand, the toner cloud speed decreased when increasing the depth of the dented electrode. An increase of the slope of nesa glass increased the toner cloud speed. However, the toner cloud speed was not significant to the system when the slope was between 0 and 5 degrees. It was also found that the width of toner cloud decreased when the applied voltage increased. Furthermore, the two overlapped cone-shaped dented electrodes could be used for generating the toner transport to the printing system. This research also explains the possible phenomena for toner cloud generation and performance.     

Toner Jumping Phenomenon in an Electric Field

This article gives a short review on fundamentals of electrophotographic printing using dry toners with conductive or insulative characteristics. The toner jumping phenomenon, TonerJet® technology, toner cloud confinement, and toner cloud beam technology in electric fields are emphasized. Theory and comparison of advantages among toner developments and transport are briefly discussed. The purpose of this article is to advance the development of a novel printing technology, “toner cloud beam,” which has the possibility of using a highly simplified toner imaging mechanism. To clarify the characteristics of conductive toner, the difference between insulative and conductive toner were compared. Unique characteristics of conductive toner are focused on: the up-and-down motion between voltage applied electrodes and cloud formation by confinement at the dented part of the electrode. The present state of the novel printing mechanism is summarized.     

全钒液流电池用碳纳米管-石墨复合电极的研究

将石墨(GP)和多壁碳纳米管(MWNT)按不同比例压片制成电极,用于全钒氧化还原液流电池电极材料,通过循环伏安、交流阻抗、充放电测试、SEM手段对MWNT-GP复合电极进行表征和分析.研究结果表明,MWNT含量为15wt%的MWNT-GP复合电极性能最佳,对组装成的静态电池在电流密度20~80mA/cm2进行充放电性能比较,电流效率均在93%以上,电压效率随着电流密度的增加而有所下降.     

Particle electrification and levitation in a continuous particle feed and dispersion system with vibration and external electric fields

Electrification and levitation of particles in a continuous particle feed and dispersion system have been studied both theoretically and experimentally. This system consisted of a vibrator and inclined parallel electrodes. A mesh and a vibrating plate were used for the upper and lower electrodes, respectively. A dc voltage was applied to one of the electrodes and the other electrode was grounded. Particles fed to the lower electrode were charged by induction and levitated upward by the Coulomb forces. When the applied voltage was high enough, the particles passed through the mesh electrode. The charge of the particles was measured with a Faraday cup, and the particle behavior was observed with a high-speed microscope camera. The particle charges were also analyzed from experimentally obtained particle trajectories and numerically calculated electric fields. Finally, the conditions for the effective levitation and dispersion of the charged particles and their mechanisms were studied and have been described in detail.     

Site-Specific Magnetic Assembly of Nanowires for Sensor Arrays Fabrication

The effect of variation in local magnetic field on magnetic assembly of 30 and 200 nm diameter Ni nanowires synthesized by template directed electrodeposition was investigated with different materials (Ni–Ni and Ni–Au) and shapes of electrodes. Ni–Au paired electrodes improved confinement of the assembled Ni nanowires across the electrode gap because of the narrower distribution of magnetic field around the gap between the two electrodes. Simulation results indicated a local magnetic field strength at the electrode tip increased by a factor of 2.5 with the use of a needle-shape electrode as compared to rectangular-shape electrode. The resistance of nanowire interconnects increased as the applied voltage was raised, and under the same applied voltage, the increase in resistance is further enhanced at lower temperatures because of higher current density.      

基于分子动力学的丝网印刷柔性传感器电极导电性机理研究

目的 研究提高丝网印刷柔性传感器电极的导电性,为提升柔性传感器的电学性能提供参考依据。方法 首先采用分子动力学（Molecular Dynamic,MD）模拟方法,建立在Wenzel模型下导电银浆团簇在不同粗糙因子下的对苯二甲酸乙二醇酯（Polyethylene Terephthalate,PET）表面铺展的分子动力学模型,其次分别计算各体系下的结合能,用以表征不同体系下PET表面对导电银浆团簇结合能力,接下来通过丝网印刷实验的方法探究银浆与不同粗糙因子PET的结合能力对传感器电极的导电性的影响。结果 仿真结果表明,导电银浆团簇在不同粗糙因子的PET表面的铺展过程中会陷入粗糙表面的凹陷处,且导电银浆与基材的结合能随着PET粗糙因子的增加而增加。实验结果表明,使用不同粗糙因子的PET作为承印物能显著提升电极的导电性。相比于未处理的PET,随着粗糙因子的增加,导电线条的电导率逐渐升高,电阻率逐渐降低,方块电阻逐渐降低。电导率最大提升了77%,电阻率最大下降了43%,方块电阻最大下降了38%。结论 导电银浆在粗糙表面铺展的过程中会渗入基材的凹陷处,增加了吸附点位,使得银浆与基材的结合更加紧密...     

Production of carbon black acrylic composite as an electrophotographic toner using emulsion aggregation method: Investigation the effect of agitation rate

Toner as a composite of colorant, polymer and additives is a primary component of electrophotographic printing and copying processes. It can be produced by conventional mechanical milling or by more recently developed chemical polymerization methods. The emulsion aggregation is a popular chemical method that allows tight control on the size, size distribution and shape of the synthesized toner particles. These characteristics are important for producing high quality, high-resolution printed images. This research investigated the effect of agitation speed on toner synthesis using emulsion aggregation method. Particle size analysis, scanning electron microscopy, and field emission scanning electron microscopy were used to study the size, shape, and morphology of toner particles. It was found that toner particles synthesized using emulsion aggregation method is spherical in shape and decrease in size as agitation speed increases. Differential scanning calorimetry and spectrophotometric analyses results showed that the toner synthesized by this method had appropriate thermal and colorimetric characteristics as compared to an industrial toner.     

墨粉的制备及发展概况

墨粉是电子成像显像专用信息化学品在IT和自动化领域的主要耗材,包括静电复印粉、激光打印粉、彩色激光打印粉等。随着静电复印机、激光打印机、彩色激光打印机等成像设备使用量的增加,墨粉的需求量快速增长。然而,制备高端墨粉的技术壁垒极高,主要为欧美和日本垄断,因此高端墨粉的研发在我国具有重大的现实意义和广阔的市场前景。简介了墨粉的构成与分类,综述了墨粉主要的制备技术及其优缺点,概述了国内外墨粉市场现状,展望了墨粉今后的研究方向。     

导电炭黑填充硅橡胶的电阻温度系数

以炭黑(CB3100)为导电相,硅橡胶为基质制备导电复合材料。研究导电橡胶中炭黑质量分数对电阻温度系数的影响,并用填料对电阻温度系数的影响。以隧道效应理论为基础,给出了导电炭黑填充橡胶的电阻温度系数计算模型,结合实验得到温度对导电炭黑/硅橡胶电阻温度系数的影响主要体现在对其电阻率的影响;基体的体积热膨胀提高复合材料的电阻率,提高了正电阻温度系数;炭黑粒子间的隧道效应降低复合材料的电阻率,增强了负电阻温度系数;在炭黑/硅橡胶中加入少量碳纳米管,利用碳纳米管和炭黑的协同补强效应,使复合材料的导电性和稳定性提高。     

Sub-micrometer particles produced by a low-powered AC electric arc in liquids

The article presents the report of the production of composites of sub-micrometer metal particles in matrix consisted of the metal compounds by means of an AC electric arc in water and paraffin solutions using electrodes carbon-metal and metal-metal (metal: Ni, Fe, Co, Cu). The advantage of this method is the low electric power (from 5 to 10 W) needed in comparison to standard DC arc-discharge methods (0.8 to 3 kW). This method enables the production of particles from conductive material also in wide range of temperature and in solvent which could be either transparent to light or opaque. Moreover the solvent can be electrolyte or insulating liquid. The microstructure of the composite layer was investigated by scanning electron microscopy (SEM), Electron Probe Microanalysis (EPMA) and X-ray. During particles production in water metal oxides were created. Additionally using cobalt-copper, nickel-copper as couple electrodes, insoluble in water copper (II) hydroxide crystal grains were created additionally which crystals shape was depended on transition metal. For iron-copper couple electrodes system the copper (II) hydroxide was not formed. Experiments with sequence production of Ni and Fe particles with C electrode assisting in molten paraffin let to obtain both Ni and Fe particles surrounded by paraffin. After solidification the material was insulator but if locally magnetic field influenced on the liquid solution in that place after solidification a new composite was created which was electric current conductor with resistivity around 0.1 omega x m, was attracted by magnetic field and presented magneto resistance around 0.4% in changing magnetic field in a range 150 mT. After mixing the concentrated paraffin with normal paraffin resistivity of the mixture increased and it became photosensitive and created small voltage under light influence.     

MEASUREMENT OF VAN DER WAALS FORCE OF TONER ADHESION EMPLOYING A LINEARLY INCREASING ELECTRIC FIELD AND DETERMINING THE TONER JUMPING VOLTAGE

Both van der Waals and electrostatic forces of adhesion between toners and substrates play an important role in electrophotography processes employed in copying machines and laser printers. We report here a method of estimating van der Waals forces of adhesion between various substrates and toners of different particle sizes. The method involves the measurement of the detachment force and the resultant current caused by toner jumping between two closely-spaced conducting parallel plates. Conducting toners are first sprayed on the top surface of the bottom plate; the voltage across the two plates is then ramped at a constant rate. When the electrostatic force of detachment exceeds the forces of adhesion between the toners and substrate, there is a significant increase of current between the two parallel plates. The particles jump from the bottom plate and reach the upper electrode. Upon reaching the upper electrode, the initial induced charge is lost and the particles acquire electrostatic charge of the opposite polarity, then move toward the bottom plate. From the balance between the forces of detachment and adhesion (comprising of van der Waals, gravitational, and electrostatic image forces), the van der Waals force between the toner and test substrates can be determined.     

电应力对HfO2栅介质漏电流的影响

使用导电原子力显微镜（Conductive Atomic Force Microscopy,CAFM）对电压应力作用下HfO2栅介质薄膜局域漏电点的形成和产生机制进行了研究,结果表明,在电压应力作用下,HfO2介质层中的缺陷被驱动和聚集形成导电通道,产生漏电点。漏电点产生的数量、漏电流大小均受电压应力和作用时间的影响。HfO2栅介质层中晶界处的缺陷密度高于晶粒处,导致晶界处更容易产生漏电通道。在栅介质击穿过程中,电压应力在诱发漏电流产生的同时产生焦耳热,对HfO2介质表面造成热损伤,导致击穿后HfO2介质表面出现凹陷。     

导电炭黑对富锂锰基层状氧化物电极性能的影响

研究了导电炭黑Super P的添加量对高电压富锂锰基层状氧化物电极电化学性能的影响,采用SEM和交流阻抗分析Super P添加量影响电极性能的原因。结果表明:高电压富锂锰基层状氧化物电极的倍率性能及循环性能均随Super P添加量增加呈先提高后降低的趋势,其中添加5%(质量分数,下同)Super P的电极具有最优的循环性能和倍率放电性能。这是因为提高Super P添加量能够增加Super P颗粒与富锂锰基层状氧化物颗粒之间的电接触,从而在电极中构建更为完善的电子导电网络,降低电极内部组分之间的阻抗,减小电极的极化,然而Super P添加量超过5%时,易发生团聚,不利于其充分发挥导电作用。     

Manipulation of small particles utilizing electrostatic force

We developed electrostatic system for manipulating small particles with diameters in the range of several micrometers to 100 μm. The electrostatic manipulation probe consists of a monopole pin electrode. When voltage is applied to the electrode, a dielectrophoresis force generated in the nonuniform electrostatic field is applied to the particle near the tip of the electrode. The particle is captured with the application of voltage, and then it is released from the probe by applying a high voltage of the opposite polarity. It is possible to manipulate not only insulative but also weakly conductive particles. A three-dimensional field calculation and a measurement of the adhesion force were conducted to evaluate the force balance for the capture and release of a particle. On the basis of these investigations, we demonstrated the manipulation of actual lunar dust returned by the Apollo 11 lunar surface mission.     

Electrographic magnetic stylus recording; A high speed non-impact magnetic printing process

An electrographic magnetic printing process is described which uses magnetically attractable and electronically conductive dry toner material deposited directly onto a dielectric layer in response to electronic current flow from one member of an array of magnetically permeable styli. The imaging process is extremely flexible in imaging speed, dot/mm resolution, continuous grey scale, and materials.     

AC electrothermal manipulation of conductive fluids and particles for lab-chip applications

AC electrokinetics has shown great potential for microfluidic functions such as pumping, mixing and concentrating particles. So far, electrokinetics are typically applied on fluids that are not too conductive (<0.02 S/m), which excludes most biofluidic applications. To solve this problem, this paper seeks to apply AC electrothermal (ACET) effect to manipulate conductive fluids and particles within. ACET generates temperature gradients in the fluids, and consequently induces space charges that move in electric fields and produce microflows. This paper reports two new ACET devices, a parallel plate particle trap and an asymmetric electrode micropump. Preliminary experiments were performed on fluids with conductivity at 0.224 S/m. Particle trapping and micropumping were demonstrated at low voltages, reaching ~100 mum/s for no more than 8 Vrms at 200 kHz. The fluid velocity was found to depend on the applied voltage as V⁴, and the maxima were observed to be ~20 mum above the electrodes     

Reversible Conductive Inkjet Printing of Healable and Recyclable Electrodes on Cardboard and Paper

Conductive inkjet printing with metal nanoparticles is irreversible because the particles are sintered into a continuous metal film. The resulting structures are difficult to remove or repair and prone to cracking. Here, a hybrid ink is used to obviate the sintering step and print interconnected particle networks that become highly conductive immediately after drying. It is shown that reversible conductive printing is possible on low‐cost cardboard samples after applying standard paper industry coats that are adapted in terms of surface energy and porosity. The conductivity of the printed films approaches that of sintered standard inks on the same substrate, but the mobility of the hybrid particle film makes them less sensitive to cracks during bending and folding of the substrate. Damages that occur can be partially repaired by wetting the film such that particle mobility is increased and particles move to bridge insulating gaps in the film. It is demonstrated that the conductive material can be recovered from the cardboard at the end of its life time and be redispersed to recycle the particles and reuse them in conductive inks.     

电弧放电法制备石墨烯及其在导电油墨中的应用

导电油墨是印刷电子技术中使用的关键电子材料, 而导电填料作为导电油墨的主要成分要求其化学性能稳定且电导率高。其中, 基于石墨烯的导电油墨因为其、透射电子显微镜、拉曼光谱等手段对制备的石墨烯进行了表征。结果表明: 直流电弧放电法制备的石墨烯为2~10层、尺寸在100~200 nm范围且纯度高、结晶性好。在此基础上, 研究了涂层厚度、热处理温度以及弯曲角度等对石墨烯导电油墨导电性能的影响。研究发现, 石墨烯导电油墨电阻率与涂层厚度、热处理温度成反比, 且随着厚度、温度的增加石墨烯导电油墨的电阻率逐渐降低。并且样品在柔性基底上经过不同角度的弯曲折叠后电阻率没有明显变化。当厚度为170 μm的样品经过360℃ (30 min) 热处理后, 石墨烯导电油墨的电阻率仅为0.003 Ω·cm。上述结果表明, 电弧法制备的石墨烯导电油墨有望成为未来印制电子领域的关键材料。     

导电功能集料碳纤维水泥基复合材料及其压敏性能

利用石墨粉和粘土基质烧制成导电陶粒,与碳纤维共同组成复合导电相,制备得到导电功能集料碳纤维水泥基复合材料。采用Instron5882材料试验机,动态电阻应变仪和直流稳压电源测试系统研究了其压敏性,发现压应力对其电阻值有显著影响;从开始加载至破坏全过程电阻值变化表现出均匀下降、平衡和迅速上升3阶段;在低加载应力循环下材料电阻变化值与应力有良好相关性,高加载应力循环下因损伤裂纹的不可复原性而使电阻出现不可逆增加;加载速率对电阻变化也有影响,低加载应力时加载速率影响较小,高加载应力时影响较大。