Abstract: A magnetic brush developing system for electrostatic duplication uses a developer having a magnetic carrier and non-magnetic toner which is transferred by the brush to an electrostatic image. A analog signal is derived using a Hall sensor in contact with the brush and adjacent to a magnet of the brush. The location of the sensor after and downstream of the transfer point provides information in the signal both as to the absolute value of the concentration (ratio of toner to carrier by weight) as well as the rate of transfer of the toner to the electrostatic image. These signals are used to control the supplying of replenishment toner to the developer only when the concentration of toner drops below a predetermined desired value and then at a rate commensurate with the rate of transfer of toner to the electrostatic image.

Abstract: An apparatus which regulates the developability of a conductive developer mixture by controlling the concentration of toner particles therein. The concentration of toner particles in the developer mixture is adjusted in response to the sensed conductivity.

Abstract: A developing apparatus is provided in which the toner concentration of a developing agent for electrostatic duplicator is detected with high precision by positively magnetizing the developing agent present in the detection region in a toner concentration detecting container. The developing agent within the detecting container is magnetized within a range of a magnetic flux density under which the permeability is not so changed with the change of magnetic field, even if a change of the magnetic flux of a magnetic roll or the like is produced.

Abstract: The invention provides an on-stream method and apparatus for analyzing of the concentrations of chemical components in a bath, especially in an electroplating bath, contained in one or more processing tanks. Moreover, the information obtained by such analysis of a single bath or of multiple baths may be efficiently employed to control such concentrations in the bath or respective baths, for example, by controlling the addition of one or more additives. The apparatus comprises a multi-steam sampling value and a computer for controlling the operation of said value. The computer also controls means for adding material to the baths in order to maintain the parameters thereof.

Abstract: An apparatus for controlling toner concentration utilizing a hollow body upon which a detecting coil is wound. The hollow body responses to the inductance of the developer passing through. The apparatus further comprises: a first digital oscillator with the frequency thereof being variable according to changes in the inductance, a second digital oscillator producing a reference signal at predetermined frequency, and a first and second digital frequency dividers for dividing the outputs of the first and second oscillators, respectively. The fist and second dividers are cleared by the divided output of the other divider. A toner supply mechanism is energized when the first frequency divider is cleared and is de-energized when the second frequency divider is cleared.

Abstract: First and second sensors (37), (39) are provided in a developing tank (36) containing a liquid developer consisting of a liquid carrier or dispersant and toner particles dispersed in the carrier. The first sensor (37) measures the electrical resistivity of the developer whereas the second sensor (39) measures the optical transmissibility thereof. Additional toner is supplied into the developer to maintain the transmissivity at a value which is a predetermined function of the resistivity. The transmissibility value is reduced as the resistivity increases, thereby maintaining the copy image density constant. The first sensor (37) includes two electrodes immersed in the developer and an A.C. or D.C. voltage is applied thereacross. The current flow through the electrodes (37) and thereby the developer is measured to determine the resistivity of the developer. Where the applied voltage is D.C.

Abstract: A cellulose fiber insulation, a manufacturing method and a plant for practicing the method. Waste paper is pulverized in a hammermill apparatus to provide a quantity of cellulose fiber particles which are air conveyed past a fog-type injection nozzle where the particles are wetted with a solution of fire and/or pest resistant and corrosion inhibiting chemicals. The wetted particles are thereafter air conveyed away from the nozzle with heated exhaust air from the hammermill apparatus to dry the particles prior to depositing them in a storage bin. The air by which the particles are conveyed may be exhausted through a filter to catch residual particles which may be returned to the storage bin or directly to the process. The sprayed solution may be prepared by a batch process or by counterflow percolation of heated liquid upward through a bed of soluble fire-retardant chemical. The concentration of chemical in the resultant saturated solution may be regulated by a thermostatic control system.

Abstract: A control apparatus for automatically controlling at least the concentration of copper-ions, hydroxyl-ions and formaldehyde-ions in an electroless copper plating bath and independently analyzing, displaying and replenishing the concentration of each such ions whereby a sample for each of the ions is discontinuously removed from the plating bath and diluted with a specific amount of water and, independently of one another, the copper-ion concentration is colorimetrically analyzed, displayed and replenished as needed, the hydroxyl-ion concentration is potentiometrically analyzed, displayed and replenished as needed and the formaldehyde-ion concentration is amperometrically analyzed, displayed and replenished as needed.

Abstract: An apparatus for detecting the density (concentration) of toner in a developer for an electrostatic recording apparatus includes an operatively moveable surface for carrying developer onto an electrostatic latent image bearing member during image development, a scraper element having at least a flat surface for scraping developer from the movable surface in a substantially steady and uniform stream along the flat face, and a substantially flat detection coil assembly having oppositely-directed faces. The coil assembly is mounted on, spaced apart from, and substantially parallel to the flat face of the scraper so that the stream of developer passes along both coil assembly faces directly after being scraped from the moveable surface, thereby enhancing the toner density detection sensitivity of the coil assembly.

Abstract: The intensity of development of latent images on dielectric receptor sheets in a liquid bath which contains a dispersion of toner particles and fills a vessel between two electrodes one of which supports a sheet in such a way that the latent image faces the other sheet is regulated by measuring the current which flows between the electrodes in response to insertion of a fresh sheet between the electrodes, comparing the measured result with a preselected reference value, and evacuating the bath from the vessel to thereby terminate the development when the ratio of measured result to the reference value is one-to-one or another preselected ratio.

Abstract: Disclosed is a device for measuring the concentration of toner in a developer mixture composed of toner and a ferromagnetic carrier material, e.g., in an electro-photographic developing device. The device comprises a measuring oscillator which comprises an inductance-including component comprising at least one coil wherein the conductor paths of the coil lie substantially in one plane; means for passing at least a portion of the developer mixture into the zone of the inductance; and means for evaluating changes in the frequency of the oscillator resulting from changes in the developer mixture composition passing over the zone of inductance. Also disclosed is an electro-photographic copying apparatus embodying the foregoing device.

Abstract: In order to determine the homogeneity of a magnetic dispersion, part of the dispersion is conducted through a measuring cell prior to its application to a base, the size, number and type of those regions of the magnetic dispersion which interfere with the homogeneity being determined with the aid of magnetic measurements. The measuring cell contains a magnetic head, a magnetic dispersion is made to flow in a stream of constant cross section past the air gap of the magnetic head, and a magnetic field at least partially penetrating the magnetic dispersion is produced. From the characteristics of the amplified output voltage of the magnetic head the various parameters of the inhomogeneities in the magnetic dispersion can then be ascertained.

Abstract: A toner concentration detecting apparatus comprises a rotatable probe having a toner-receiving face, a case housing the probe, means attached to the case for detecting an amount of toner on the toner-receiving face, and a port formed in the case for discharging stray toner particles from the case. The toner-receiving face is put in contact with a magnetic brush of a developer mechanism, separates toner particles from a developer and receives them. The detecting means includes a light-emitting element for applying light to the toner-receiving face and a light-receiving element for receiving the light reflected by the toner-receiving face and converting the light into an electric signal. The stray toner discharging port extends in the direction in which acts centrifugal force generated by the rotation of the probe and is located near the light-emitting and light-receiving elements.

Abstract: An apparatus for detecting the concentration of toner particles contained in the developing powder is disclosed wherein the developing powder comprising a mixture of magnetic carrier particles and the toner particles is transported while being adsorbed by a magnet roll, and rubbing an electrostatic recording surface lightly to develop an electrostatic latent image. After development, the developing powder is separated from the magnet roll, flows along a guide path, and forms a magnetic path for a flat detecting coil with the flat surfaces thereof placed in the guide path in the same direction as the flow of the developing powder. In response to the magnitude of the inductance of the detecting coil, an electrical circuit produces an electrical signal corresponding to the mixing ratio between the magnetic carrier particles and the toner particles in the developing powder.

Abstract: An exposure unit radiates a light image of an original document onto a charged photoconductive member to form an electrostatic image through localized photoconduction. A developing unit applies a powdered developing substance comprising carrier particles and toner particles to the photoconductive member to develop the electrostatic image and produce a toner image which is transferred and fixed to a copy sheet to produce a permanent reproduction of the original document. The tone density, or the ratio of toner particles to carrier particles in the developing substance is electromagnetically measured, and the developing ability of the developing substance is opticaly measured. The developing substance is replaced when the difference between the toner density and developing ability exceeds a predetermined value. Prior to exposure with the light image a reference electrostatic image is formed on the photoconductive member and the electrostatic potential thereof is measured.

Abstract: A system and method for monitoring and maintaining a predetermined concentration of material in a fluid body or carrier includes a control arrangement for detecting the transmissivity of a flow cell in each of two states. One of the states during which the flow cell is observed contains substantially no fluid present therein but provides a basis for determining the degree of existence of external factors affecting measurements made via the flow cell. The measurements for one state are subtracted from the measurements for the other in order to determine the transmissivity of the fluid body itself as distinguished from the combination of fluid body and flow cell.

Abstract: A powdered toner mixture comprising a non-magnetic toner component and a ferromagnetic carrier component is caused to flow downwardly through a vertical conduit by gravity. An electromagnetic coil is wound around the conduit and energized with an alternating electric signal. An electrically conductive and magnetic mass is disposed inside the conduit. The permeability of the toner mixture decreases as the toner density, or the ratio of the toner component to the carrier component, increases. The lower the permeability of the toner mixture, the greater the proportion of magnetic flux passing through the mass. The flux passing through the mass induces eddy currents therein which, in combination with hysterisis and skin effect losses, dissipate a portion of the electric signal. The amount of power dissipation is a function of the relative proportion of flux through the mass and thereby the toner density and, when measured, provides a measure of the toner density.

Abstract: Apparatus for monitoring the concentration of toner in a mass of developer mix including the toner and carrier particles, having a sampling cylinder inside which the developer mix flows. An accumulating cylinder is disposed over the sampling cylinder. At the upper end part of the accumulating cylinder, a guide plate is disposed by which the developer mix is supplied to the accumulating cylinder. At the lower end part of the accumulating cylinder, a developer mix supplying roll is disposed by which the developer mix at a fixed flow rate is supplied to the upper end opening of the sampling cylinder. On the other hand, at the lower end opening of the sampling cylinder, there is disposed a magnet roll by which the developer mix at a fixed flow rate is discharged from inside the sampling cylinder.

Abstract: Deterioration of a dry developing substance causes toner particles to be so strongly adhered to carrier particles that they cannot be readily separated therefrom. The present apparatus comprises means for applying a predetermined electrostatic or air suction force to the developer to readily remove toner therefrom except for spent toner particles strongly adhered to the carrier particles. The toner density, or the ratio of toner to carrier particles, is then measured electromagnetically or optically and compared to a reference value. The developer deterioration determines what proportion of toner will be removed from the developer by said force and thereby the subsequently sensed toner density. The higher the sensed toner density, the greater the degree of deterioration.

Abstract: An electrophotographic liquid developing system for overcoming the effect of photoconductor background potential in which during the passage of the image area through the developer unit a constant current source supplies a small current to the development electrode to raise the electrode to a potential of the same polarity as and of a magnitude greater by predetermined amount than that of the average background potential of the image area in a preferred embodiment the constant current source is provided by a small plate mounted in and insulated from the transfer corona housing and having such dimensions as to provide the required current. Preferably, the output of the constant current source is controlled in response to a measurement of the conductivity of the developer.