Abstract The surface states model is successful in predicting many salient features of charge transfer in insulative materials, which is critical to electrophotography. This article will discuss how the surface chemistry controls the physics and the chemical potentials, and how it fits the surface states model. The interrelationship of acid‐base K a /K b values of the materials in contact, measured by inverse gas chromatography, the highest occupied molecular orbitals and lowest unoccupied molecular orbitals and their excited states calculated using DFT (density functional theory) quantum mechanical modeling, the chemical potentials measured by the Kelvin method, and triboelectric charging data are studied. It will be shown that a precursor complex of the contacting materials, prior to the charge transfer event, can be calculated by DFT to predict triboelectric charging both qualitatively and quantitatively. This article focuses on polytetrafluoroethylene, Kynar and PMMA polymers, as well as silica, titania, and alumina.
Abstract A three dimensional calculation of a first transfer subsystem in electrophotography is carried out and toner scattering on a transfer belt is simulated. This simulation consists of an electric field calculation and a toner movement calculation, and toner scattering around the periphery of the dot is investigated. The simulation shows that the formation of toner scattering arises from the toner jumping across the transfer gap before the photoconductor contacts the belt. The effects of transfer parameters on toner scattering are investigated with the simulation. To prevent toner scattering, the position of the roller, adhesion force, transfer bias, toner charge, and resistivity of the belt should be optimized to create an appropriate electric field distribution, and so that the toner transfer occurs in a small gap or in a contact nip between the photoconductor and the belt.
Abstract ElectroInk, developed and manufactured by HP Indigo Division for its digital printing presses, is a complex fluid of unique rheological and electrical properties. Depending on the shear and the electric field the ink may be solid- or fluidlike. As ElectroInk propagates in the press from the ink reservoir to the substrate, the concentration increases while the structure of the ink changes from a dispersion of non-interacting particles to an elastic solid. The authors’ model treats ElectroInk as an interwoven structure of two continuous phases, one being a network of pigmented resin particles and the other the incorporated liquid. In an external electric field the network shrinks like a sponge and partial phase separation occurs. Application of the model is shown for the design of 100% transfer of ink from roller to roller in the press, which is necessary to meet the principal requirement of digital printing, that each printed page can be different.
Abstract The use of mobile phone camera technology in systems for capture of documents or three-dimensional objects is becoming increasingly popular. Compared to conventional flatbed or sheetfed scanner technology, such systems pose special image quality concerns due to the fact that the underlying camera and illumination technologies are inherently low-cost. Thus, each unit is designed to operate closer to the threshold of acceptable quality. So there are higher levels of noise and greater non-uniformity across the image plane, as well as greater unit-to-unit variability. Consequently, there is a need for a solution that can provide a detailed assessment of the spatial non-uniformity of key image quality metrics within the field of view of the image capture system, and which can be robustly and efficiently computed. This article proposes a specially designed composite target and an automatic analysis tool for image quality inspection of camera-based document/object capture systems. The target and analysis tool can be used during product development, as well as on the manufacturing line for real-time inspection.
Abstract In the fast-changing world of actionable printing, there has recently been a huge increase in the adoption of two-dimensional (2D) barcodes for enterprise and consumer applications. The Data Matrix 2D barcode has become a primary carrier of supply chain information, most notably for track and trace. The QR (Quick Response) 2D barcode, meanwhile, has spread from Japan to the rest of the world, and is a standard means of connecting a barcode to a URL. The authors have previously developed a 3D (color + 2D) barcode that increases the barcode data capacity and provides branding possibilities. In this article, the authors introduce the four-dimensional (4D) barcode (color + 2D + time) as a means of using the same barcode location for multiple barcodes through time. This supports many enterprise workflows, including document lifecycles. In this article, the authors consider the theory behind incremental information objects, of which progressive barcodes are a key incarnation. The authors describe how progressive barcodes are created and utilized. They also show that the set of progressive barcodes comprising a lifecycle can contain up to twice the data of the associated single-time 3D color barcode. Finally, the authors present some real-world applications of these new barcodes.
Abstract It is essential to understand preferred skin colors for color reproduction in the display industry. This article presents three psychophysical experiments that were conducted to determine the preferred skin color ranges of East Asian women by East Asian observers on the chromatic and lightness components of CIELAB color space displayed on a standard sRGB-gamut display. In the first experiment, the preferred skin color was searched using various settings of correlated color temperatures (CCTs) and luminance levels on the screen. The results indicate that the most preferred skin color on a display had small differences between various images varying in CCT and luminance level. In the second experiment, a more precise preferred skin color center was produced. The preference scores were analyzed, and the preference map of skin colors was presented on the CIELAB a∗ b∗ plane. The final experiment examined the relationship between the lightness of facial skin color and the perceived preference on a display. It was conducted to examine the effect of the lightness component on the preference of facial skin color. It was found that the <mml:math overflow="scroll"> <mml:mrow> <mml:mo>(</mml:mo> <mml:msubsup> <mml:mrow> <mml:mi>C</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>a</mml:mi> <mml:mi>b</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>∗</mml:mo> </mml:mrow> </mml:msubsup> <mml:mo>,</mml:mo> <mml:msub> <mml:mrow> <mml:mi>h</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>a</mml:mi> <mml:mi>b</mml:mi> </mml:mrow> </mml:msub> <mml:mo>)</mml:mo> </mml:mrow> </mml:math> value of the most preferred skin colors of East Asian women is (25.4, 50.5), with an L∗ value of 65.
Abstract This article describes modifications to the CIECAM02 appearance model based on the Hunt‐Pointer‐Estevez (HPE) matrix together with a revised nonlinear luminance adaptation function. The modified model removes the mathematical inconsistencies for both the forward and the inverse models that occur with CIECAM02 for highly saturated colors. The modified CIECAM02 can be considered an interim solution for use in color management for cross-media color reproduction before an updated version of CIECAM02 is developed by CIE Technical Committee. The modified model, however, performed 0.3 CV units worse than the original in predicting visual data derived by magnitude estimation, and an average of 1.3 CIELAB color difference units worse when predicting corresponding color data sets.
Abstract Plasma treatment is a commonly used technology to modify the wetting behavior of polymer films in the production process for, e.g., printed electronics. As the effect of the plasma treatment decreases in time, the so-called “aging effect”, it is important to gain knowledge on how this effect impacts the wetting behavior of commonly used polymers in order to be able to optimize production processing times. In this article the authors study the wetting behavior of polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polycarbonate (PC), fluorinated ethylene propylene (FEP) and polyimide (PI) polymer films after plasma treatment in time. The plasma treatment was performed using a novel maskless DBD plasma patterning technology, i.e., μPlasma Printing, at atmospheric pressure under nitrogen atmosphere. After treatment, the samples were stored at room temperature at 30%‐40% relative humidity for up to one month. An increase in wettability is measured for all polymers directly after μPlasma Printing. The major increase in wettability occurs after a small number of treatments, e.g., low energy density. More treatments show no further beneficial gain in wettability. The increase in wettability is mainly due to an increase in the polar part of the surface energy, which can probably be attributed to chemical modification of the surface of the investigated polymers. With the exception of FEP, during storage of the plasma treated polymers, the wettability partially declines in the first five days, after which it stabilizes to approximately 50% of its original state. The wettability of FEP shows little decline during storage. As the storage time between production steps is mostly under two days, μPlasma Printing shows good promise as a pre-treatment step in the production of printed electronics.