Electrophotographic Materials Research Articles

Electron holography study of electric field variations

This paper presents a review of the recent electron holography studies on electric field variation that have been carried out using multifunctional specimen holders. In addition to the standard inner potential analysis, studies on electric field variations around field emission tips have been carried out. The electric field variations caused by ballistic emission in the case of a field emitter made of a TaSi(2) nanowire have been analyzed using electron holography. The charges and electric fields in electrophotographic materials such as toner particles and organic photoconductors have been quantitatively evaluated after equipping the specimen holder with a piezodriving probe to shield the specimens from electron irradiation. The conductivity and electric field variations in the case of Ag-based conductive adhesives have been analyzed by applying an electric current through the holder. Finally, the characteristic charging effect induced by electron irradiation in biological specimens has been studied. It has also been pointed out that under certain experimental conditions, the stationary orbits of electron-induced secondary electrons can be located by electric field visualization.

Electrophotographic layers of trigonal Se in the binder obtained by reduction of SeO 2 by hydrazine

In this paper the method of forming electrophotographic material by reduction of diethilselenite to elemental selenium by hydrazine is described. Electrophotographic layers thus obtained were found to be bipolar and possess the following parameters:initial potential U in≃4.l0 5 V/cm, time of dark half-decay τ 1/2≃80 s, sensitivity according to half-decay of potential S 1/2≃0. l5 1k/s and residual potential U res &1sim;0.1U in . Obvious disadvantages associated with electrophotographic layers (Els) of t-Se were eliminated by this process.

Laboratory automation a strategic step in laboratory integration

Our quality control laboratory provides chemical analysis of electrophotographic materials for the Office Imaging Division of Eastman Kodak Company. A long-term commitment to quality improvement has been made by the Manufacturing Quality Assurance Organization to meet the analytical needs of both the manufacturing and new product development communities. Specific improvements made in the areas of measurement traceability and data audit trails have become an important part of manufacturing quality systems documentation, and are essential for certification or product registration under the ISO 9000 series of standards. Implementation of laboratory automation can serve as a key step in moving toward an integrated laboratory, where sample preparation, analysis, and data reporting are fully automated. A plan was developed that capitalizes on the advantages of flexible automation, dedicated automation, and a laboratory information management system. Flexible automation applications include robotic systems for sample preparation and analysis of electrophotographic toners by high-performance liquid chromatography, UV-VIS spectroscopy, and particle size distribution. By adding these capabilities in the planned stages, significant improvements in reliability and response time have been seen for routine samples and for new method development.

CCD arrays for readout of electrophotographic latent images

Arrays of charge sensing elements have been fabricated for nondestructive electronic readout of latent images on electrophotographic materials. The arrays are implemented in the form of a monolithic integrated circuit in which each sensing element is a 5- mu m *5- mu m MOS capacitor; 2048 such elements are arranged in a linear format with effective 5- mu m element-to-element pitch. On-chip circuitry allows for multiple sampling at each sensing site for enhancing signal-to-noise ratio. The resulting signals from the sense elements are multiplexed onto charge-coupled-device (CCD) shift registers for high-speed serial readout. To allow for the small sensor-to-film gap (on the order of 10 mu m) required for capacitive sensing, the chip's bond pads are recessed in deep grooves below the active array surface. The array is packaged within a hydrostatic air bearing which maintains a constant and uniform gap. The response of the array to targets of high spatial frequency recorded on various electrophotographic materials is in excellent agreement with analytical predictions.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

A review of progress of electrophotography in Japan

Major contributions from Japanese investigators in the field of electrophotography are reviewed. Scientific research into understanding photoelectric behavior of zinc oxide and other electrophotographic materials, efforts for developing new electrophotographic systems (e.g., electroplate marking), and analysis and improvement of electrophotographic processes are among the topics included.

Note on the Discharge of Electrophotographic Material by Light

The discharge behavior of different electrophotographic materials was studied by measuring (dV/dt) − V curves. If it can be shown in a separate experiment that the discharge current is a primary saturated photocurrent (i.e., it is independent of surface potential at high potentials) a simple interpretation of these curves is possible in the saturation region. The shape of the curves is very sensitive to the details of the discharge process. It was shown that the shape of both the (dV/dt) − V and the V(t) curves can be strongly influenced by geometric effects (a change of depletion layer capacitance during discharge without trapping) or by trapping of charge carriers. From these considerations we can conclude that the interpretation of discharge curves V(t) or (dV/dt) (t) requires some care and is only meaningful if the type of discharge current and the voltage dependence of the capacitance are known.

Organic Photoconductive Layers Sensitized with Triarylcarbonium Salts

The electrophotographic layer consisting of poly-3,6-dibromo-N-vinylcarbazole was sensitized with twenty-seven kinds of triarylcarbonium salts. The carbonium salt compounds used have the formula: [equation] The novel sensitizers differ in two points from the well-known triphenylmethane dyestuffs sensitizers for the organic electrophotoconductors. First, the triphenylmethane dyestuffs have at least two radicals such as amino or dimethylamino radical. The novel sensitizers have not such a radical. Second, the novel sensitizers have an extreme ability to increase the photosensitivity of organic photoconductors. When the photoconductive polymer sensitized with carbonium salts is applied to semitransparent paper, cellophane papers or plastic sheet, a transparent electrophotographic material can be obtained. These materials are superior to sensitized zinc oxide paper in photosensitivity. Such a transparent material can be used as a master for diazo copy, for overhead projection copy, or for slides.

Organic Photoconductive Layers Sensitized with Triarylcarbonium Salts

The electrophotographic layer consisting of poly-3,6-dibromo-N-vinylcarbazole was sensitized with twenty-seven kinds of triarylcarbonium salts. The carbonium salt compounds used have the formula: [equation] The novel sensitizers differ in two points from the well-known triphenylmethane dyestuffs sensitizers for the organic electrophotoconductors. First, the triphenylmethane dyestuffs have at least two radicals such as amino or dimethylamino radical. The novel sensitizers have not such a radical. Second, the novel sensitizers have an extreme ability to increase the photosensitivity of organic photoconductors. When the photoconductive polymer sensitized with carbonium salts is applied to semitransparent paper, cellophane papers or plastic sheet, a transparent electrophotographic material can be obtained. These materials are superior to sensitized zinc oxide paper in photosensitivity. Such a transparent material can be used as a master for diazo copy, for overhead projection copy, or for slides.

Characteristics of Electrophotographic Papers—Part 1

The primary parameters of electrophotographic papers are surface charge, and the decay of this charge under both dark and illuminated ambient conditions. The inter-relationship of these parometers is of great practical signiftcance in machine design. It is suggested that the results from conventional static methods for their measurement can be misleading. Special equipment has been constructed for the examination of electrophotographic materials under dynamic conditions. Experimental results are presented together with an indication of their value in assessing the practical performance of electrophotographic papers and their influence in machine design.