Agfa Gevaert Nv

Agfa-gevaert Ag

Willy G Verlinden

Lucien A De Schamphelaere

Freddy M Librecht

Emile F Stievenart

Paul M Cassiers

Yvan K Gilliams

Leo N Vackier

Richard Wick

Friedrich Bestenreiner

Dieter Giglberger

Walter Schott

Jozef Eduard Marien

Gunter Wetzel

Josef Leonard V Engeland

A method of producing toner-developed electrostatic images involving the repetitive performance of a copying cycle comprising the steps of corona charging a photoconductive layer at a determined voltage level, information-wise photo-exposing said charged photoconductive layer, developing the exposed photoconductor with charged toner particles to a toner image, transferring the applied toner image to a receptor, and restoring the photoconductive layer to a rest potential for the next cycle; and between successive copying cycles, maintaining said photoconductor in the dark for a randomly varying time period. The number of performed copying cycles in each series is registered by electronic means and an output signal is generated; the period of time between series that the photoconductor is maintained in the dark is measured and a corresponding output signal is generated. The respective output signals are inputed to electronic control means which (a) based on a relation between the actual surface potential of the photoconductor and the number of copying cycles performed in a series, measures the voltage change in the photoconductor surface from the actual number of cycles in a series, (b) based on a relation between the actual change in surface potential of the photoconductor and the dark recovery duration measures the voltage change in the surface potential after an actual dark recovery period, (c) and then gives a combined control signal indicating the overall change in surface potential from the beginning of one series of cycles to the beginning of the next series. Finally, the corona voltage is regulated substantially according to the combined control signal.

Electrostatic copying method including compensation for photoconductor

Toner dispensing control in a xerographic printer wherein a toner dispenser is controlled in response to a reference magnetic density value that is variable during the running-in period of a fresh toner mixture, thereby to take account of the changing packing density of the mixture during such period.

Toner dispensing control

Toner dispensing control in xerographic printing, wherein a toner dispenser is controlled during a first period of use by means measuring the exposing radiation applied to the photoconductor, and during a further period of use by means responsive to the relative permeability of the toner mixture. Thus, over-tonering during the running-in period of a new toner mixture is avoided.

Toner dispensing control in xerographic printing, wherein a toner dispenser is controlled during the initial period of use of a new toner mixture by a first control unit that is at least predominately responsive to the number of discrete exposures of the photoconductor, and during a further period of use a second control unit that is at least predominately responsive to the relative electrical permeability of the toner mixture. Over-tonering during the running-in of a new toner mixture is thereby avoided.

A process of producing a liquid image, wherein an insulating material bearing an electrostatic charge pattern detectable at its surface is developed by wetting with a developing liquid according to such charge pattern and in which process developing liquid is brought substantially uniformly in close proximity to or in contact with the material with at least two developing liquid applicator means, which are disposed in succession along the path followed by the material and which supply developing liquid to the material in such a way that the liquid image is gradually built up by amounts of liquid offered by such successive applicator means.

Method for the development of electrostatic charge images

An apparatus for liquid development of latent images on sheets or webs comprises a plurality of applicator stations which sequentially deliver processing liquid to the latent image bearing surface of the sheets or webs. The latter are transported above the respective applicator stations with the concerning surface in downward direction. A controlling mechanism provides for the arrestment of the liquid supply before the trailing edge of the sheet or web has passed over the respective applicator station for the provision of not wetting the backside of the latter. The apparatus is extremely suited for developing latent electrostatic half-tone images on a high polymeric support.

Processing apparatus

A process of producing a liquid image, wherein an insulating material bearing an electrostatic charge pattern detectable at its surface is developed by wetting with a developing liquid according to such charge pattern and wherein in said process developing liquid is brought substantially uniformly in close proximity to or in contact with said material by the use of at least one developing liquid applicator means followed by at least one other means that is capable of removing from the charge-carrying member some of the developing liquid already deposited by the or a said preceding applicator means.

Method for the development of electrostatic charge patterns

A method for fixing a liquid toner image on a thermo-adhesive layer of a recording material by irradiating such layer with high intensity short duration light pulses. The energy is sufficiently high to cause a partial melting of the layer so that the toner particles become absorbed thereon but the duration of the light pulse is sufficiently short to avoid a permanent deformation of the recording material itself. A favourable supplementary effect is that during irradiation a simultaneous evaporation of the residual toner liquid takes place.

Method for fixing electrophoretically formed toner images

A method and apparatus suited for forming radiographs wherein distribution patterns of penetrating radiation representing radiographic information to be recorded are recorded in terms of electrostatic charge patterns on successive charge-receiving areas distributed along a carrier, by bringing such areas successively into a chamber in which each such area is exposed to an ionizable fluid while this is exposed in an electric field to a pattern of penetrating radiation thus producing in such fluid positive and negative charge carriers and forming with the positive or negative charge carriers a corresponding electrostatic charge pattern on such area, the latter being brought by subsequent movement of the carrier to a position outside such chamber where such electrostatic charge pattern is transferable or developable to form a transferable visible record.

Radiography

A color copying apparatus wherein a copy carrier sheet is attracted by the suction chamber of a carriage which is reciprocable along a horizontal path past an exposure station and along a battery of aligned developing units. After each exposure with a different filter, the sheet is moved into register with a different developing unit. The carriage is moved by an endless belt which has a pin receivable in one of two vertical slots on a plate-like female coupling member of the carriage. Guide rollers automatically disengage the pin from the coupling member when the carriage reaches the exposure station. The suction chamber is then attracted by electromagnets so that two sockets of the suction chamber move downwardly and receive stationary centering pins which hold the carrier in a predetermined position during each of a series of exposures. This insures accurage register of successively projected and developed images in the three basic colors.

Growing community of inventors

Edegem, Belgium

Willy G Verlinden