Toner-based printing technologies such as electrophotography have excellent electronic printing characteristics. The toner is controlled by electrostatic force, which is determined by the product of the toner charge and the electric field acting on the toner. In electrophotography the toner is attracted to an electrostatic latent image and forms an image. Because the toner is controlled by electrostatic force, high speed printing on plain paper can be realized. Electrophotography consists of six complex processes: charging, exposure, development, transfer, fixing, and cleaning. Various technologies have been proposed to realize a simpler printing mechanism. An electrostatic printing mechanism is described in which charging and exposure occur within a single process that generates an electrostatic latent image. As examples of direct printing by this simpler mechanism, TonerJet® and toner cloud beam are reviewed. As a fundamental element of toner-based printing technology, the toner charging mechanism is summarized.

Environmental and consumable operating conditions have been observed to have significant impact on the color electrophotographic (EP) process. This article presents the results of utilizing operating information to improve the sensor mapping which predicts tone reproduction on printing media based on measurements on substitute media in the calibration. In this article, time-series sensor data and color measurements have been collected from off-the-shelf color EP platform printers under a variety of operating conditions. The data analysis shows that the sensor mapping has distinctive behaviors under different levels of relative humidity and cartridge toner consumption. In addition, the sensor mapping has been found to be sensitive to tone level. A new prediction model is proposed to compensate for environmental, consumable and tone-level disturbances. The experimental results show the proposed model is able to improve the prediction accuracy by 30% on average across the Cyan, Magenta, Yellow, and Black (CMYK) primary colors.

This work employs principal component regression (PCR) to improve tone prediction accuracy for color electrophotography (EP). During calibration, primary color patches at different half-tone levels are printed on a belt and measured using on-board sensors. Regression models are developed to predict primary color tone values on output media from these on-board sensor measurements. The prediction accuracy of the regression models directly impacts the quality and consistency of color reproduction. Analyses have revealed a high degree of correlation among the on-board sensor measurements of the calibration patches from the same primary color. This indicates that multiple on-board sensor measurements are linearly correlated and using multiple on-board sensor measurements to predict the tone value may improve prediction accuracy if the collinearity of the measurements is taken into consideration. In this study, a PCR-based approach is applied to handle the multicollinear measurements in estimating the regression model coefficients. Experimental results show the proposed PCR models reduce root-mean-squared error by 24.7% over ordinary least-squares regression models.

In liquid electrophotography, deformable blades are used to remove ink residuals and liquid from the organic photoconductor (OPC) drum. The thin layer remaining after the blade can produce undesirable chemical residuals on its surface. When bombarded by ions at the charging station, this layer can oxidize and affect the OPC's electrical properties. In this work the authors investigate the blade-OPC drum conjunction under fully flooded inlet and outlet conditions; a theoretical model incorporating elastohydrodynamic (EHD) considerations was developed where a deformable blade was deflected by a moving surface (OPC). Unlike typical EHD problems, which are widely discussed in the literature, the authors case consists of a contact line which causes a singularity problem in the analysis. This singularity is due to the blade's sharp corner edge prior to its deformation. In order to overcome this singularity, the authors first solved the elastic-static deformation of the tip using finite element simulation software (COMSOL) and combined hydrodynamics considerations afterwards. Experimental results were found to closely agree with the authors calculations.

Prolonged exposure of a commercial organic photoconductor in a plasma environment corresponding to an industrial electrophotographic process caused the formation of a parasitic surface layer with properties that are different from the original photoconductor. The parasitic film consists of a heavily oxidized surface region and oxygen-free subsurface layer with a chemical composition similar to the original photoconductor but having a significantly different bonding arrangement. The formation of this film has been correlated with damage induced by the energetic particles and UV photons originating from the electrophotographic plasma discharge. An in-depth understanding of the formation and the properties of this parasitic layer could provide an effective means to overcome its detrimental impact on printing cost and quality.

Using the transmission control protocol/internet protocol (TCP/IP) stack as a model of layered protocols, the authors propose a next-generation reliable print service called the Gutenberg-Landa TCP/IP to handle the routing of pages through a print service provider (PSP). Gutenberg-Landa TCP/IP will be an expanded TCP/IP protocol: just as data packets flow through the internet to form web pages, so printed pages flow through a PSP; but unlike data packets, printed pages must be routed through a series of irreversible physical transformations. This wide range of transport mechanisms and transformations (such as raster image processors, high speed digital presses, paper handling, and finishing devices) are all connected by their opportunity to read and add information to the printed page. Given the proper infrastructure, the printed page itself can dynamically route itself through the PSP. Through its design of its protocols, Gutenberg-Landa TCP/IP will unify reliable printing, finishing, and delivery into a single paradigm that would provide the same quality of service as the internet: a highly efficient and robust print infrastructure with near 100% uptime and the ability to grow its print capacity without limit. Gutenberg-Landa TCP/IP is a prime example of a cyberphysical system: its goal is to seamlessly integrate physical manufacturing infrastructure with internet and networking infrastructure.

Printed electronics is a new technology for manufacturing electronic structures using standard printing processes. One emerging application area is in microelectronics packaging, where printing the interconnections allows manufacturing modules in miniature size. The basic principle is that the integrated circuits are molded into a background material such that the connection pads are left visible on top. After the background substrate has hardened, the wiring is printed on top of the module by using conductive ink. Typically, however, there are unidealities in the manufacturing process that result in the components and their connection pads being slightly displaced. This article describes an alignment and adaptation system that adapts the wiring bitmap to match the displaced components on a per-module basis. Moreover, the adjusted bitmaps can be combined together to enable printing of several modules at the same time.

The ink jet printing technique can be an alternative fabrication route for LCD color filters. The source of luminance nonuniformity in color filters fabricated by ink jet printing is described and methods to minimize this nonuniformity are presented. Both drop volume uniformity of the ink jet printhead and morphology of the printed color filter layer are important to achieve required luminance uniformity. Some practical methods to control the drop volume uniformity were tested and proposed. Morphological control of the printed color filter was also studied. Desirable interfacial energy between color filter and black matrix was modeled and tested using both plasma treatment and solution treatment.

We consider the problem of predicting the spectral reflectance of paper samples immersed in ink mixtures of varying ink concentrations. Relying on an adapted version of the Kubelka-Munk theory, we predict the reflectances of the samples dyed by ink mixtures. We first derive a method to calculate the effective scattering coefficient of an inked paper sample as a function of its absorbance coefficient. Then we learn from a single sample the reduction in ink concentrations when two inks are mixed. Using these ink concentration reduction factors, we can then predict the reflectances of paper colored by ink mixtures of various nominal concentrations.