Abstract: A substantial change in charge on toner in a development station due to a reduction in relative humidity as the station warms up is compensated for by applying heat from an externaI source to the station when the station has not been warmed up. For example, when the station is turned off or in a condition of idle. This feature is particularly usable in a station having a rotating magnetic core.

Abstract: An image forming apparatus has a magnetic brush toning station for applying toner to an electrostatic image. The brush includes a rotatable magnetic core positioned inside a non-magnetic sleeve. To facilitate the removal of developer from the sleeve after it has toned an electrostatic image, a skive located against the sleeve downstream of the toning position has a roughened surface upon which the developer rolls or tumbles to move away from the sleeve and ultimately fall into a mixing sump.

Abstract: A development station for applying dry toner to an image member includes a rotatable magnetic core and an input skive to determine the height of the developer nap on a shell surrounding the core. Toner flakes showing up in the toner application on the image member are substantially reduced by replacing a previously metallic skive with a non-conductive skive to prevent heating of the skive from eddy currents created by the rotating core.

Abstract: Apparatus for applying toner to an electrostatic image includes a sump for holding developer, which developer preferably includes a component having high coercivity and permanent magnetism. An applicator for moving the developer through a development zone includes a rotatable magnetic core and a sleeve around the core, which sleeve includes roughened portions leading to and away from the development zone and a smooth portion directly facing the development zone. The sleeve may also have smooth portions on its lateral crosstrack edges.

Abstract: The level of charge on toner in a developer is sensed or otherwise determined in an image forming apparatus. In response to such determination, a charge control member is adjusted between positions in which it triboelectrically charges the toner more or less because of greater or lesser contact with the toner.

Abstract: A magnetic brush device for applying toner to an electrostatic image includes an applicator having a rotatable core. The sleeve for the core is made of an insulating material and preferably has a thin metallic coating on the outside of the sleeve defining the sleeve's outside surface.

Abstract: A toning station particularly usable in a multicolor image-forming apparatus includes an applicator and a developer mixing mechanism. A transport roller with a fluted surface transports developer from the mixing device to the applicator. A magnetic gate is positioned inside the transport roller and has a first position in which it attracts developer from the mixing device to the transport roller to facilitate delivery of developer to the applicator. The magnetic gate is movable to a position opposite the applicator where it inhibits passage of developer to the applicator to stop the development action of the station.

Abstract: Image forming apparatus includes a toner cleaning device for cleaning toner off an image surface. The cleaning device includes a cleaning applicator for moving magnetic particulate cleaning material past the surface to be cleaned. Particulate material is moved from a sump to the cleaning applicator by a transport positioned between them. A detoning roller is positioned to attract toner from particulate material associated with the transport. When the cleaning device is not cleaning, it has a mode of operation in which the transport and the detoning roller continue to operate to continue to detone particulate material which moves from the sump around the transport and back to the sump.

Abstract: A toning roll assembly in which a rotatable core member with magnetic poles disposed about the periphery thereof is positioned within a hollow shell so that the shell-to-core clearance, and therefore, the magnetic field strength on the outside surface of the shell varies from point-to-point on the shell. Magnetically attractable developer particles are fed onto the shell's surface at a point of higher field strength and moved through a point of lower field strength on the shell. The latter field strength is such so that under the operating and design parameters of the assembly, only the amount of developer required to properly tone the latent image on an associated photoconductor remains magnetically supported on the shell for transport to the photoconductor after the developer passes the point of lower field strength.

Abstract: An image forming apparatus has a magnetic brush toning station for applying toner to an electrostatic image. The brush includes a rotatable magnetic core positioned inside a non-magnetic sleeve. To facilitate the removal of developer from the sleeve after it has toned an electrostatic image, a skive located against the sleeve downstream of the toning position has a roughened surface upon which the developer rolls or tumbles to move away from the sleeve and ultimately fall into a mixing sump.

Abstract: An image-forming apparatus particularly usable in making multicolor toner images includes toning stations in pairs. First and second toning stations each have a toner applicator. A spacing roller or disk is mounted at each end of each applicator. Because the toning unit includes two stations and two applicators, the four disks can be used to accurately position the applicators with respect to an image surface such as a photoconductive drum.

Abstract: An image-forming apparatus, for example, a color electrophotographic apparatus, includes two development stations. Each development station includes an applicator with a rotatable component which moves developer into toner-applying relation with an electostatic image carried on an image member. The two rotatable components are driven by a single motor selectively according to whether the motor is driven in a forward or reverse direction. A one-way clutch in the drive train of each rotary component prevents rotation of that component when the other station's rotary component is being driven.

Abstract: A development apparatus for developing images with magnetic toner particles contained in magnetic developer material. The development apparatus has a magnetic development roller and a device for removing a partial amount of magnetic chains of the developer material from the magnetic development roller. The device includes a first magnet generating a first magnetic field for standing the magnetic chains on a first end, and a second magnetic generating an opposite magnetic field for standing such chains on a second and opposite end. The device also includes a skiving plate that is positioned between the first and second magnetic fields.

Abstract: A development apparatus in an electrostatographic copier or printer includes a housing having two parallel, cylindrical side-by-side recessed sump sections partially forming and overlapping segment therebetween, and a pair of rotatable mixers having radially extending paddles that interleaf within the overlapping segment of the sump sections. The development apparatus as such is particularly capable of producing chopping, folding, end-to-end and side-to-side mixing and charging movement of developer material therein, in order to provide high and reliable quality image development.

Abstract: An electrographic development apparatus has a sump for receiving developer material including carrier particles and toner particles. A magnetic brush receives development material from the sump and moves the material into a position relative to an electrostatic image carried on an insulating surface so that toner particles can be transferred to the electrostatic image to develop such image. A ribbon blender in the sump mixes the toner and carrier particles of the developer material, circulates developer material axially within the sump, agitates and shears the developer material, promotes tribocharging, and feeds developer out of the sump along a path leading to the magnetic brush.

Abstract: A development station for electrographic apparatus has a magnetic brush which receives developer material from a sump and applies it to a latent image on a photoconductor. A metering slot for the developer material is provided adjacent the magnetic brush. A gate mechanism controls flow of developer material through the slot by moving between an open position adjacent the metering slot to allow developer material to pass through the slot and a closed position to block flow of developer material through the slot. A wiper blade removes excess developer material from the brush after the image has been developed. The wiper blade is movable into and out of engagement with the magnetic brush and is coupled to the gate mechanism so that when the gate is closed the wiper blade is out of engagement with the brush.

Abstract: Magnetic brush development apparatus for applying developer material to a latent image on a photoconductor includes a housing having a sump which receives a supply of developer material. A magnetic brush spaced from the sump applies the material to the latent image of a photoconductor as the photoconductor is moved past the magnetic brush. Developer material is fed to the brush through an elongate feed slot adjacent to the brush. A feed mechanism delivers developer material from the sump through the slot to the magnetic brush. The feed mechanism includes a rotatable shell and a plurality of magnets that are located within the shell and attract developer material to a portion of the shell. The shell has a deeply fluted outer surface that holds the developer material attracted to the shell as it is delivered from the sump to the slot. The fluted outer surface also assists in removing excess developer material from the area adjacent the slot.

Abstract: An electrographic development station is disclosed which includes three magnetic brushes which sequentially apply toner to an electrostatic image on a moving photoconductor. The two upstream brushes rotate counter-current with respect to the movement of the photoconductor and have magnetic fields which overlap so that developer is carried from one brush to the other. The third magnetic brush rotates co-current with regard to such photoconductor movement. The two counter-current brushes apply a large quantity of toner to an electrostatic image on the photoconductor and the co-current brush applies a sufficient amount of toner to develop any incompletely developed portions of an electrostatic image.

Abstract: In an electrographic development apparatus having a magnetic brush and a sump wherein an auger transports developer from the sump to the brush, the auger being disposed in a tube located next to an inclined surface extending between the tube and the magnetic brush. The tube is provided with a plurality of openings. As the auger rotates it transports developer from the sump through the tube out of its opening to the inclined surface where it is distributed to the magnetic brush.