Abstract: A development station for applying toner to an electrostatic image includes a rotatable magnetic core and a roughened sleeve on which developer moves to develop the image. The outside surface of the sleeve contains fine extrusion-formed serrations, which serrations provide a roughness for the outside surface contributing to movement of developer in response to rotation of the magnetic core.

Abstract: A toner container has three chambers for holding three different color toners. The container is receivable by a receiving structure having a pair of opposing slots for receiving flanges on the base of the toner container. The receiving mechanism is part of a development device which includes a movable carriage for moving a plurality of development units into alignment with a development position. A portion, for example, an applicator of each development unit is movable with respect to the rest of the unit into toning relation with an image member at the development position.

Abstract: A toner monitor in an electrostatographic machine is automatically calibrated when a toner monitor is periodically caused to read a simulated nominal toner concentration. Any difference between the monitor's output and that expected for the simulated nominal toner concentration is applied to a compensation device. The simulated nominal toner concentration signal is obtained by periodic alignment of the toner monitor with a magnetically permeability member.

Abstract: A series of electrostatic images carried by a drum or similar image member are toned with different colored toners by a movable developing device. The developing device moves a series of developing units to a position aligned with the drum. An applicator is an aligned unit is moved relative to the rest of the unit toward the drum to operatively position the unit for developing each electrostatic image.

Abstract: An applicator of a developing portion of an image-forming apparatus is permanently located with respect to an image member. A plurality of developing units are separately positionable with respect to said applicator for supplying developer to the applicator. Each of said development units can contain toner of different colors. The applicator and image member can be part of a cartridge which is separately loadable into the image-forming apparatus.

Abstract: An applicator for a development unit is precisely positioned with respect to an image member, such as a photoconductive drum. A pair of pins are fixed with respect to the image member and fit in a pair of holes that are fixed with respect to the applicator. A roller on each of opposite ends of the applicator engages a surface of the image member to properly space the applicator and image member, while the pins and holes control relative lateral and rotational movement.

Abstract: A development station for developing electrostatic images includes a housing which has a vertically oriented separating wall which divides the housing into first and second chambers. In assembly both chambers are open at the top permitting ready loading of one chamber with a mixture of toner and carrier and the other chamber with substantially toner. The separating wall includes an opening at the bottom for passage of toner into the chamber containing the mixture. A toner applicator is located at the top of the chamber containing the mixture and a cover is permanently affixed across the tops of the chambers, totally sealing the chambers except for an opening in the cover opposite the toner-applicator. Because of the design of the station, especially the chambers which are open at the top for easy loading of toner and carrier, the station can economically be made disposable.

Abstract: A replaceable development station usable for developing electrostatic images in an apparatus having a toner monitor and a channel for slidably receiving the development station includes a chamber containing a supply of a development mixture of toner and carrier particles. A recess is defined in one wall of the chamber for receiving the toner monitor, the recess being defined by a thinned region of the wall such that the toner monitor is separated from the developer mixture by a wall region substantially thinner than the general wall thickness.

Abstract: A device for developing electrostatic images carried on a film belt in an apparatus receiving the developing device includes device location surfaces which seat on apparatus location surfaces in the apparatus to locate the device with respect to the apparatus. Film support surfaces on the device support the film belt a fixed spacing from a developer applicator. The film support surfaces are located within tight tolerances with respect to the surface of the applicator to provide accurate positioning of the applicator and film belt.

Abstract: A device for developing electrostatic images includes a toner supply chamber for holding a supply of dry toner and a feed member located generally at the bottom of the supply chamber. To break up agglomeration of toner in the supply chamber an agitator, for example an elongated polypropylene fiber brush, is placed on top of the feed member and is supported totally at its periphery by the feed member and associated walls of the supply chamber. As the feed member rotates, the agitator is rotated to maintain the toner in particulate form.

Abstract: Disclosed is apparatus for scavenging charged particles (e.g. triboelectrically carrier particles) from an electrographic recording element. Such apparatus comprises a conductive grid positioned in close proximity to the path of the recording element, and biasing means for electrically biasing the grid so as to attract the charged particles from the recording element yet prevent them from depositing on, and thereby contaminating, the grid.

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: An electrographic development apparatus comprises a magnetic brush applicator having cooling means for dissipating thermal energy from the developer as it is transported by the brush. Such cooling means preferably comprises means for passing a cooling fluid through the interior of the brush while in use. Alternatively, such cooling means comprises a hollow skive through which a cooling fluid is circulated.

Abstract: Contrast and/or density adjustment of developed electrographic images is effected in a development system comprising a hard magnetic carrier and a magnetic brush having a rotary core and shell. The adjustment is effected by cooperatively varying the core and shell rotation rates, within predetermined ranges, in a manner which maintains the operative developer linear velocity generally equal to, and co-current with, the velocity of an electrographic image member's movement through the development zone.

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: An improved magnetic brush development device features magnetic counterpoise means located in opposing relation (across the development zone) with the primary magnetic brush field adjacent the development zone. The magnetic counterpoise means has a repelling polarity relative to the primary magnetic brush field and cooperates to form a compressed, smooth nap at the development zone.

Abstract: Improved electrographic development apparatus and procedure for use with partially-conductive developer employs transport of the developer through a first development zone in a direction generally countercurrent to a moving image member and through a second development zone in a direction generally co-current to the moving image member. The extent of image development within each such zone is controlled by the rate of developer transport and/or the magnitude of developer bias, so that overall development of the different portions of large solid image areas (particularly leading and trailing portions of such areas) is equalized.

Abstract: Improved electrographic development apparatus and procedure for use with partially-conductive developer employs transport of the developer through a first development zone in a direction generally countercurrent to a moving image member and through a second development zone in a direction generally cocurrent to the moving image member. The extent of image development within each such zone is controlled by the rate of developer transport and/or the magnitude of developer bias, so that overall development of the different portions of large solid image areas (particularly leading and trailing portions of such areas) is equalized.

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.