Abstract: Electrostatographic toning with charged toner particles which are transported along a conveyor having an array of repeating sets of electrodes upon which an electrostatic traveling wave pattern is established. The traveling wave pattern causes already charged toner particles to slide and roll along the conveyor to a selection site whereat individual toner particles are either directed toward the receiver or are returned to a developer reservoir. The width of each of the electrodes for the traveling wave grid is comparable to the size of the toner particles such that the particles are transported individually along the conveyor. At the selection site, unwanted particles are deflected from the path to a receiver. The receiver can be placed against a conveyor plate to avoid the divergence and bouncing problems.

Abstract: A scavenging device for recapturing charged carrier particles from a moving image-bearing surface includes a first pickup member and a second pickup member. The first pickup member is mounted adjacent toner and carrier particles on the image-bearing member, and is biased electrically to a polarity relatively opposite to the polarity of the charged carrier particles. The second pickup member is also mounted adjacent toner and carrier particles on the image-bearing member to be effective at a point downstream of the first pickup member. The second member, as such, is electrically grounded for capturing from the image-bearing member wrong sign carrier particles.

Abstract: A multicolor reproduction is made by uniformly charging a photoconductive member, imagewise exposing that member to create a first electrostatic image, developing the first electrostatic image with a toner of a first color to create a first toner image, preferably uniformly recharging the photoconductive member, imagewise exposing the charged member creating a second electrostatic image, developing the second electrostatic image by the application of toner of a second color to the exposed areas. The process can be repeated for any number of colors. The multicolor image is then transferred in a single step to a receiving sheet. The second and subsequent development steps are carried out by a magnetic brush developing device employing hard magnetic carrier particles that are tumbled through a development zone which tumbling does not adversely affect the prior toner images.

Abstract: An electrostatographic reproduction machine includes a toner concentration monitor having a resistive element through which electrical current is passed. The resistive element is heated by the electrical current. In a steady state mode, the resistive element transfers heat to its surroundings and attains a steady state temperature dependent upon the heat transfer characteristics of the surroundings. The toner concentration is detected by measuring the power into the resistive element. The heat transfer characteristics are determined by the thermal conductivity and the flow rate of the developer mixture.

Abstract: Apparatus and method for electrophotographically producing high quality reproductions which contain different content types. Photoconductor image sectors are subjected to separate optical exposures selected for (1) good tone-scale reproduction of continuous-tone image portions and (2) high-contrast reproduction of line-type image portions. Photoconductor background area, which border continuous-tone image portions, are discharged to a level below the system's development level. Color line-art from a black and white original is also provided for in a color-copier by exposing a separate original containing a swatch of the color to be reproduced on the same image frames exposed to the image of the line-art. A digitizing tablet is used in combination with a selective erase means to provide selective screening and/or spot color effects. The digitizing tablet may be incorporated to use the exposure platen and may be of the sonic type or other types not employing grid lines visible to the photoconductor.

Abstract: A multicolor electrophotographic reproduction apparatus and method are provided for reproducing a copy in a selected colors. The apparatus includes a digitizer for inputting information denoting the location(s) of the pictorial information and the location(s) for which selected coloration is desired. The respective colors desired for reproduction of the information may be chosen from a menu of twenty-five or more colors stored in memory. In addition to an exposure source for reproducing an image of the original upon a photoconductor the apparatus also includes an illumination source for selective erase and a second illumination source which illuminates the photoconductor through a halftone screen to control the charge level on areas of a color separation image frame in accordance with the color selected to thereby effect the color which a reproduction will have.

Abstract: Electrographic development is obtained by predeterminedly rotating an alternating pole core of a magnetic brush applicator, within a surrounding applicator shell, to supply developer, of the kind including small particle, hard-magnetic carrier and electrically insulative toner, to an electrostatic imaging member which moves past a development station with predetermined linear velocity. The shell can be stationary or rotate at a velocity significantly less than the image member velocity. The core is predeterminedly rotated so that (i) its fields effect a large portion of transport through the development zone and (ii) the developer moves co-currently with the imaging member and at a linear velocity generally equal to the imaging member velocity.

Abstract: Improved electrographic development is obtained in the presence of a development electrode field by predeterminedly rotating both the core and shell of a magnetic brush applicator to supply developer, of the kind comprising small particle, hard-magnetic carrier and electrically insulative toner, to an electrostatic imaging member which moves past a development station with predetermined linear velocity. In one preferred embodiment the core and shell are predeterminedly rotated so that the shell moves through the development zone at a rate preventing toner that is plated-out on the shell from affecting image development and so that the developer moves co-currently with the imaging member at a generally equal linear velocity.

Abstract: In a novel electrographic copying method and apparatus, a latent electrostatic image is formed on an insulating layer of an electrophotographic element and, before, during or after the formation of the latent electrostatic image, there is created a plurality of charge islands, such as by an exposure through a screen. These charge islands are distinct and in addition to any charge islands which result from the image-forming step. After establishment of the charge islands and the latent electrostatic image, the resulting charge pattern is developed with a developer which either is at least partially conductive, i.e., has a maximum resistance of about 10.sup.9 ohms, or is rendered so by the phenomenon of electrical breakdown.

Abstract: A light-sensitive vesicular imaging element and a method of manufacture are provided, comprising a vesiculating layer which includes a binder and vesiculating agent which liberates gas upon exposure to activating radiation, and an overcoat which contains a polymer soluble in a solvent in which the binder of the vesiculating layer is substantially insoluble. Upon imagewise irradiation of the element, gas bubbles are generated in the exposed areas. The bubbles may be developed to a visible record by overall heating.

Abstract: In a novel electrographic copying method and apparatus, a latent electrostatic image is formed on an insulating layer of an electrophotographic element and, before, during or after the formation of the latent electrostatic image, there is created a plurality of charge islands, such as by an exposure through a screen. These charge islands are distinct and in addition to any charge islands which result from the image-forming step. After establishment of the charge islands and the latent electrostatic image, the resulting charge pattern is developed with a developer which either is at least partially conductive, i.e., has a maximum resistance of about 10.sup.9 ohms, or is rendered so by the phenomenon of electrical breakdown.