A sleeveless magnet roller developing system was studied by using a non-magnetic toner and an iron carrier. A developing roller made from a sintered ferrite magnet, with 32 magnetic poles and 0.025 T in magnetic flux density, was employed in this study. Imaging characteristics and developing behavior were examined in the sleeveless magnet roller developing system in both normal and opposite developing directions. The influence of toner concentration on the developing characteristics was also examined. It was confirmed that the developing system had an optimum developing condition for best imaging properties. It was also found that the toner concentration in the developer was stable during continuous printing. These results suggest that developing characteristics can be controlled by automatic control of the toner concentration.
Laser-toner-fusion (LTF) is a dry, high quality electrothermographic imaging process for producing both monochrome and color images from electronic input. The process steps involve using a magnetic brush to apply a uniform toner layer to a substrate imagewise exposing the layer to a high power IR laser that tacks the toner to the substrate; removing the unexposed toner using a magnetic brush toner removal device; and finally, fixing the image using conventional fusing. The removed unexposed toner can be recycled thereby eliminating waste. The exposed toner particles are partially buried in a thermoplastic layer and are therefore robust to abrasion. The process is insensitive to visible radiation and can be carried out in ordinary roomlights. The energy required for imaging is between 150 and 300 mJ/cm2. The application most thoroughly investigated is image setting where color separations with 2540 pixels per inch resolution, and with transmission density of 4.0, have been made to produce high-quality 4-color images.
The main properties and a design concept of modern wide format display graphic media are presented. It is stated that the development of ink jet media requires a detailed understanding of the basic interactions within the materials used in the ink jet receptive coatings. Theoretical and practical aspects of the consequences of polymer–polymer interactions in ink jet receiver coating are discussed. It is shown that the charge density on the chain of the macromolecule has an influence on the formation of soluble and insoluble aggregates in the coating mixtures. Several examples are presented how the type of modification and charges of polyvinyl alcohol will have an effect on print quality and waterfastness. The effect of the ink jet formulation components' ratio on prints quality, image gloss and waterfastness is discussed.
Various silicone–acrylic block copolymers were prepared by a free radical copolymerization technique, in which we used poly(dimethyl-siloxane) containing azo groups as a macromolecular initiator in reactions with acrylic monomers, including functional monomers. The copolymer solutions were coated onto substrates by using various application methods and subsequently cured by using either crosslinking agents or UV light. Advancing (A) and receding ( R) contact angles of the resulting films were measured in various inks. These films were found to be hard enough to form a nozzle face, and exhibited over 80° of A and 60° of R when in an ink, which are superior values to those observed for silicone or fluorinated coating films. The ink resistance of the films was evaluated by changes in A and R before and after soaking the films in various inks at 60°C for 4 weeks. The durability of the films was outstanding. The excellent properties were found to be attributable to the formation of a microdomain structure, and to be influenced by domain spacing rather than silicone content.
The tail region of the photocurrent transient observed in the conventional time-of-flight measurements has been experimentally studied as a function of the applied field and sample thickness for amorphous selenium stabilized with 0.2–0.3% As alloying and ∼10 ppm Cl doping (stabilized a-Se). The stabilized a-Se films used in the present study were typical x-ray photoconductors for use in x-ray imaging with a detector thickness in the range of 133–425 μm. Dispersions arising from the mutual Coulombic repulsion of charge carriers was found to give a noticable contribution to the total spread of the carrier packet even at relatively low injection level and extrapolating this function to zero injected charge. The hole transit time dispersion, ΔtTOF, reveals a power law electric field (F) dependence of the form ΔtTOF ∼ F−n where n ≈ 1. It is shown that the observed dispersion cannot be interpreted on the basis of the multiple-trapping model nor conventional diffusion while the concept of charge carrier transport within a random potential landscape allows one to explain the observed field dependence of the hole photocurrent transients in terms of a Gaussian distribution of the effective carrier drift mobilities in which the normalized mobility spread Δμ/μ is 0.083 – 0.042.
We introduce a new pigment processing approach, namely Lewis acid pigment solubilization (LAPS), for the fabrication of organic pigment thin film devices. The process involves the solubilization of an organic pigment in a Lewis acid/nitromethane solution. The resulting solution can be used to solvent cast pigment/Lewis acid thin films, which are then washed with an aqueous solution to remove the Lewis acid and give the final pigmented layers. Alternately, the pigment/Lewis acid solution can be used for acid pasting to give pigment wet cakes, which can then be used for preparing In Situ pigment dispersions suitable for solvent coating. A wide range of organic pigment thin film devices can be fabricated using these processes, as we demonstrate in this article for the fabrication of organic photoreceptors.
Recent data for some toners and carriers have shown that the tribo value, q/m, is independent of the toner concentration. This is contrary to the conventional response in which the tribo value decreases as the toner concentration is increased. Because conventional models seemingly do not predict this behavior, new models have often been proposed to explain this effect. In this work we examine two toner–carrier pairs for which the tribo values appear to be independent of toner concentration. This result is obtained when separate developers are made at different toner concentrations. By changing the toner concentration using a technique that preserves the surface properties of the toner and carrier, we show that the conventional m/q:toner-concentration dependence is obtained and is consistent with the Gutman–Hartmann (G–H) model. The unusual behavior in which the tribo value appears to be independent of the toner concentration is a result of changes in the toner and carrier surface composition when developers are prepared and mixed at different toner concentrations. Surface measurements of toner and carrier confirm toner-concentration-dependent surface modifications. We also compare the G–H model to other published data showing m/q independent of toner concentration. In the latter case, there are no anomalous surface effects. The data were taken over a wide range of toner concentration: in the low toner concentration regime, the dependence of m/q is small. We found that the G–H model is consistent with the data at both low and high toner concentration due to a slight curvature in the model that is difficult to observe experimentally unless the data are taken over a wide range of toner concentration.
A camera under general motions allows the absolute quadric to be determined uniquely for self-calibration. For turntable motions, the absolute quadric cannot be determined uniquely, and will lead to ambiguities in 3D reconstruction. However, some fixed points and lines will arise as a result of turntable motions, and can be related to the calibration matrix. In this article, we have made two contributions for self-calibration under turntable motions. First, a detailed theoretical analysis on ambiguities based on absolute quadric is given. The ambiguities are derived. Second, using constraints on the physical characteristics of the camera, the ambiguities are removed up to a single parameter family. Experiments on real turntable image sequences verified our findings, which we used to perform a 3D reconstruction.