Abstract: A reproduction apparatus is provided including a development apparatus having a capability for precharging replenishment toner particles being added to a triboelectric charging sump containing partially depleted two-component developer material. The precharging capability of the development apparatus is provided by an AC bias and a first DC bias connected to a first toner particle metering member. A second DC bias is connected to a second metering member. The precharging capability of the present invention is particularly useful during development of images requiring large amounts of toner particles.

Abstract: A developing system of the type using a two-component developer and capable of reproducing image densities and halftone images stably with no regard to changes in ambient conditions and aging. At least two toner image patterns each having a different toner density are formed on a photoconductive element. The amounts of toner deposited on the individual patterns are sensed by a photosensor, while the supply of toner to a developer and the dynamic range of a latent image are controlled in combination in response to the output of the photosensor.

Abstract: In an image forming apparatus, a toner container is provided for stocking a toner. In a body of the image forming apparatus, an opening is provided for supplying the toner to the toner container, and an opening cover for closing the opening when the toner is not supplied to the toner container. In the toner container, a rotator is provided so as to discharge the toner from the toner container into a developing device via a toner feed device. Moreover, the image forming apparatus includes an opening cover detector and a control section. The opening cover detector detects whether the opening cover is opened, and the control section prevents the rotator from driving when the opening cover detector detects that the opening cover is opened.

Abstract: An image forming apparatus is capable of forming a good image without a color shade and a dropped color by coating uniformly photosensitive toner particles on a supporting member. The image forming apparatus includes a coating amount detecting unit for detecting an amount of the photosensitive toner particles coated on the supporting member, in the vicinity of a coating unit. Therefore, the image forming apparatus can determined whether a required amount of the photosensitive toner particles is coated on the supporting member, or not. When a required amount of the photosensitive toner particles is coated on the supporting member, an exposure operation is executed. When there is a part on the supporting member which is not coated with enough photosensitive toner particles, the coating unit is operated again. This processing is repeated until the whole of the supporting member is coated with the enough photosensitive toner particles. After this, the exposure operation is executed.

Abstract: The present invention relates to a toner image density detecting mechanism for an image forming apparatus which includes an image bearing layer supported on a rotatable cylindrical member, a device for forming a plurality of toner reference patterns on the image bearing layer at respective positions which equally divide a circumference of the cylindrical member, a detector for detecting an image density of the toner image of the reference pattern, and a controller controlling an image forming condition in accordance with an output of the detector; wherein an average of the image densities is determined for use in a control operation of the controller. Preferably, the toner used has a reflective or absorbing rate not less than 1.5 times that of the image bearing layer.

Abstract: An applicator for a development unit is precisely positioned with respect to an image member, such as a photoconductive drum. The signal strength of the toner monitor is used to accurately locate each developer unit under a stationary photoconductor. The incremental distance from a home position required to position each development unit precisely under a stationary photoconductor is placed in a non-volatile memory so that the information can be used to control the drive motor to repeat the precise positioning at a later time.

Abstract: An image forming apparatus is loaded with a developing device capable of being easily exchanged, and a toner sensor for detecting a toner density is provided in association with the developing device. An output signal of the toner sensor approaches 0 V as a weight of a developer becomes small. Therefore, when the output signal from the toner sensor is detected prior to an agitating screw is operated when a power source is turned-on, it is possible to determine whether a developing device attached at that time is an unused or used one in accordance with the output signal. In addition, the output of the toner sensor when the developing device is an unused one is stored in a backed-up memory as a reference value for controlling a toner density during an actual operation.

Abstract: An image forming apparatus includes a developing unit for toner-developing a latent image formed on a photoreceptor, and a dual-component developer consisting of carrier particles and toner particles is contained in the developing unit. A toner concentration in the developing unit is sensed by a magnetic sensor. An output voltage of the magnetic sensor is applied to a microcomputer through an analog-to-digital converter. The microcomputer sets a toner supply time in accordance with a fuzzy inference based on the output voltage of the magnetic sensor and a change amount of the output voltage of the magnetic sensor. A toner supply motor is driven for the set time. Consequently, the toner supply roller supplies toner particles to the developing unit from a toner box.

Abstract: An image forming apparatus includes a developing unit and a photoconductive drum. A toner sensor is disposed in a toner mixing chamber of the developing unit. A mixing member is included in the chamber for mixing and frictionally charging the toner. A detection device is mounted on the unit for detecting the residual quantity of density of the toner according to the output voltage of the sensor. The residual quantity or density of the toner is detected by sampling an output voltage of the toner sensor at predetermined times during a predetermined period while the mixing member is rotated at a specific constant speed, and averaging the sampled vales. As a result correct data for the residual quantity or density of the toner can be obtained.

Abstract: A particle deposition system having an atomizer, wafer transport, sheath flow means, particle counter and computer control for accurately depositing a desired density of particles onto a surface. The sheath flow keeps an article clean, while the particle flux in the deposition chamber is rising from zero to an equilibrium state. The particle counter measures particle flux by sampling the atmosphere in the deposition chamber. The computer determines when the rate of change of particle flux is substantially zero and then actuates transport of the article completely or partially out of the sheath flow into the mist of falling particles. The computer also calculates the required deposition time for providing the article's surface with a desired particle density, actuating transport of the article back into the sheath flow after the desired density is reached. The operator of the system can specify particle size, desired density and full or partial coverage of the surface with particles.

Abstract: An apparatus for producing a superconducting oxide film with stable properties by metal organic chemical vapor deposition, suitable for mass production, is provided with a gas analyzer comprising a differential pressure meter 38 between a raw material gas collector tube 35 provided in a transfer line 8 for leading a raw material gas to a film forming chamber 10 and a bypass line 37, a dilution gas line 49 interlocked with the differential pressure meter 38 and for leading a dilution gas to the raw material gas collector tube 35, a gas separation column 42 branched from the bypass line, a gas detector 31 connected to the gas separation column 42, flow rate controllers 50 for carrier gases 43 and 45 and a thermostat 13 for heating all the lines.

Abstract: A monitor for sensing the concentration of toner particles in the development station of an electrostatographic machine, which has a curved sump inner wall surface, includes a solenoid having a coil-form with one end adapted to be positioned adjacent to the outer surface of the sump wall, and a shield at least partially surrounding the solenoid. The shield has an end adjacent to the wall, and the surfaces of the ends of the central coil-form and the shield define a substantially cylindrical surface which conforms to the shape of the inner wall of the sump. Preferably, the surfaces of the ends of the coil-form and the shield are adapted to be substantially equal distant for the inner wall of the sump of a received development station.

Abstract: In accordance with the present invention an apparatus is provided for use with a developer container adapted to retain a quantity of developer material, the developer material including varying concentrations of magnetic carrier material and toner material. The toner concentration sensing apparatus comprises a device for generating a magnetic field within the developer container. The apparatus further comprises a device for controlling the generating device to selectively generate the magnetic field within the developer container, wherein a preselected portion of the developer material is compressed by the magnetic field and a signal is generated across the generating device, the signal across the generating device varying as a function of the concentration of the toner.

Abstract: A toner monitor system includes a toner monitor having an output signal which is proportional to the toner concentration of a measured development mixture and further to an applied control voltage. The control voltage is set such that the toner monitor output voltage midpoint is constant regardless of environmental changes. The output voltage is centered at mid range for a nominal toner concentration, and the control voltage setting used to center the toner monitor output voltage at its midpoint is stored during a setup cycle. A reference member having a temperature stable magnetic permeability is positioned to align with the toner monitor so as to simulate to the toner monitor a nominal toner concentration, wherein the control voltage setting centers the toner monitor output voltage at its midpoint for the nominal toner concentration.

Abstract: A magnetic recording device includes a movable body having a magnetic layer and an arrangement for writing a predetermined magnetic image on the movable body. A developing arrangement is controlled to blow a magnetic fluid onto the movable body in order to develop the magnetic fluid. The magnetic fluid is circulated except at times when the image is being developed by the magnetic fluid.

Abstract: An apparatus which develops an electrostatic image with marking particles. The apparatus includes a developer roller for transporting the marking particles to a position adjacent an electrostatic image for the purpose of developing the image. During deposition of the marking particles on the image, the apparatus senses the charge thereon and in response to the sensed charge, additional marking particles are dispensed into the developer roll housing for use by the developer roller. The apparatus further includes an impoved method for periodically determining the actual concentration of the marking particles within the developer housing in order to modify the rate at which the marking particles are replenished, thereby maintaining an equilibrium concentration of marking particles within the developer housing.

Abstract: A photoelectronic image forming apparatus reproduces an image on the basis of an electrostatic latent image produced on a photo-sensitive body by using a developer containing a toner and a carrier, and comprises a plurality of toner density measuring units for respectively producing outputs each indicative of a toner density of the developer and a toner density determining unit responsive to the outputs for determining an actual toner density so as to precisely control the tone of the image.

Abstract: A developing apparatus which includes a plurality of developing units individually provided with sensors for detecting amount of toner accommodated therein, includes a judging device for judging whether or not sensor outputs of other developing units are below a replenishable amount when a sensor output of one developing unit falls below a replenishing requiring amount, and a replenishing display device for urging toner replenishment, based on the result of the above judgement, with respect to the developing unit having the sensor output below the replenishing requiring amount and the developing unit whose sensor output is below the replenishable amount.

Abstract: A method of resetting a toner shortage condition and a toner shortage indication associated with a developing device of an image forming apparatus. When the developing device has reached a toner shortage condition, a toner stortage indication is produced for urging one to supply a fresh toner or to replace a toner cartridge. The toner shortage condition and toner shortage indication are reset only when a predetermined period of time expires from the instant when one opens a door or a cover of the apparatus for the supply of toner to the instant when one closes it after the supply of toner.

Abstract: A toner is locally concentrated on a portion of the interior of an image forming apparatus when, e.g., a door of the apparatus is opened/closed or its power source is switched on, resulting in a nonuniform toner concentration. This nonuniform toner concentration is uniformized by consuming the toner within a predetermined time period by forced printing. A variation in toner concentration can be restored at a high speed, thereby preventing formation of a defective image caused by a variation in toner concentration.

Abstract: In order to prevent excessive developer, after regulating the height of the developer on a developing sleeve, from being accumulated on a partition plate even during the time when a developing apparatus is in a non-driven condition, the partition plate is provided, in a surface thereof facing a toner-concentration sensor, with holes for causing the developer to fall downwardly therethrough. Alternatively, an AC voltage is applied to the partition plate, or the partition plate is adapted to be swung or vibrated, or the partition plate is adapted to be movable so that the position of the partition plate during the time when the developing apparatus is in the non-driven condition is different from the during the time when the developing apparatus is being driven.

Abstract: A toner content control apparatus senses the toner content of developer in a developer station, and performs toner content control by replenishing the consumed toner in the developer station according to the result of a comparison between the sensed toner content and the predesignated standard value. The toner content control apparatus of the present invention is realized by providing a toner content sensor having a sensitivity control circuit. A controller, when the developer is changed, determines an optimum sensor sensitivity control data with which the sensor gives an optimum sensitivity. The controller outputs sensor sensitivity control data to the sensitivity control circuit and updates the sensor sensitivity control data by reducing or increasing the data by a correction value according to whether the difference between the output data of the sensor and the predesignated reference value is positive or not.

Abstract: A developer unit which stores a supply of developer material has a capacitance cell positioned therein contacting the developer material. The capacitance cell measures the change in capacitance of the developer material and generates a signal indicative thereof. The capacitance change is caused by a change in the dielectric characteristics of the developer material due to changes in the moisture content thereof. This signal, in combination with a signal indicating the concentration of toner particles in the developer material, is used to control various processing stations in the printing machine employing the developer unit.

Abstract: A method for the situ measuring of a sample of a porous material having a gaseous fluid and fine granular material located within its pores and, in particular, for determining the concentration of the fine granular material within the sample. The method includes the steps of generating a first acoustic wave signal of known amplitude and phase velocity, directing the first acoustic wave signal through the sample, receiving a second acoustic wave signal representing the first acoustic wave having passed through the sample, and determining the concentration of the fine granular material in the sample from the changes between the first acoustic wave signal and the second acoustic wave signal.

Abstract: A toner density control device of an electrophotographic recording apparatus in which development is conducted by a plurality of developing units with two-component developer wherein a toner density detecting device can detect the density of toner loaded in the plurality of developing units according to the variation of magnetic permeability of the developer. The detecting device is composed of a sensor provided to each developing unit, and a signal processing unit to process the output of the sensor selected by a selector. And toner is supplied according to the difference between the detected value of the detecting device and the reference value which is previously established.

Abstract: A developing apparatus which includes a plurality of developing units individually provided with sensors for detecting amounts of toner accommodated therein, includes a judging device for judging whether or not sensor outputs of other developing units are below a replenishable amount when a sensor output of one developing unit falls below a replenishing requiring amount, and a replenishing display device for urging toner replenishment, based on the result of the above judgement, with respect to the developing unit having the sensor output below the replenishing requiring amount and the developing unit whose sensor output is below the replenishable amount.

Abstract: A replaceable development station is provided for use with an electrostatographic machine in which a toner monitor is automatically calibrated when a fresh development station is loaded into the machine. The detected toner concentration in the development station is used by the monitor as a reference signal against which future readings are compared. The reference signal is reset upon machine power-up correspond to the detected toner concentration in the development station, but only when there is a fresh development station in the machine. The development station provides for indicating when the reference signal has previously been set for the developer mix. The reference value would not be reset upon other than the first time the machine is powered up with a particular development station. The indicating means is preferably a frangible member such as an electrical fuse.

Abstract: A method of detecting toner in the toner supplying unit of a developing unit wherein a toner supplying roller is caused to make a single turn, the duration of a signal indicating "no-existence of toner" issued during this single turn period is accumulated by timer function of a control unit. When a total sum of accumulated signal timer duration is longer than a first preset time, including a constant margin added to the difference between the time required for a single turn of the toner supplying roller and the time required for passing over the toner detecting surface by a cleaning means, the "no-existence of toner" condition is detected for the toner supplying unit.

Abstract: A toner end detection apparatus comprises a toner tank which accommodates a toner, a toner detection sensor which has a surface exposed within the toner tank and outputs a detection signal and made up of an ultrasonic sensor which oscillates at a predetermined frequency when no toner is adhered on the surface, a setting part for variably setting a set value, a measuring part for measuring an oscillation time of the toner detection sensor in response to the output detection signal of the toner detection sensor, and a discriminating part for discriminating a toner end based on a comparison of the set value which is set by the setting means and the oscillation time which is measured by the measuring means. The toner accommodated within the toner tank is less than a predetermined quantity when the toner end is detected.

Abstract: The transporting speed of a developer transporting roller is switched over depending on the condition whether a developing unit is operated for developing process or the developing unit is not in action for developing operation, and a comparable standard value for making a decision whether toner replenishment is required or not is changed based on the toner density value detected by a magnetic sensor when the developing unit is operated or is not in action for developing operation. When the developing unit has finished a predetermined number of operations, and image forming operation is suspended, a developer stirring and transporting roller is driven for a duration of time corresponding to the number of developing operations conducted, and toner density detection and toner replenishment is carried out corresponding to the toner density detected.

Abstract: An improved magnetic brush development apparatus for applying developer material to a latent electrostatic image wherein measurement of toner level is facilitated. The apparatus includes a housing defining a sump portion adapted to contain a supply of developer material, and a magnetic brush located substantially within the housing in spaced relation to the sump portion for applying developer material to the latent image. A feed mechanism located within the housing between the sump portion and the magnetic brush transports developer material from the sump to the magnetic brush, and a mechanism located in the sump portion agitates developer material and transports developer material to the feed mechanism. Developer material in the sump portion is replenished by a device which includes a reservoir for replenishment material adjacent to the sump portion, a flow communication path between the reservoir and the sump portion, and a device for selectively controlling flow of replenishment material through the path.

Abstract: An image forming apparatus includes an image forming unit and a main body. The image forming unit is detachably mounted in a main body of the image forming apparatus and has at least a developing device for storing a predetermined developer for forming a desired image. A sensor circuit generates a detection signal upon detection of the state of the developer in the developing device. A connecting section outputs the detection signal to the main body. A transmitting section has a single portion to be connected and transmits, to the main body side, the detection signal and a signal representing a mounting state of the image forming unit, which is generated in accordance with a coupling state of the connecting section with respect to the single portion.

Abstract: A developing apparatus is provided for use in an electrophotographic apparatus. The developing apparatus includes a developer case in which a developer having a mixture of a toner and a carrier is stored, a developing roll which is located in the developer case and which is partially exposed to the outside of the developer case adjacent to a photosensitive drum, a front stirring roll which is located below the developing roll in the developer case to make a flow of developer in the developer case and below the developing roll, a rear stirring roll which is located rearwardly of the front stirring roll in the developer case to create a flow of developer in a direction opposite to the direction of flow of the developer produced by the front stirring roll, and a guide plate located between the front and rear stirring rolls for guiding most of the developer which falls form the developing roll towards the front stirring roll.

Abstract: An electrophotographic image forming apparatus employing a two-component developer including toner and carrier comprises: a developing unit containing the developer; a toner concentration sensor provided on the developing unit for detecting the concentration of the toner included in the developing unit; a comparing apparatus for comparing a value detected by the toner concentration sensor with a prescribed concentration reference value; a supplying apparatus for supplying toner to the developing unit; a controlling apparatus for controlling toner supply by the supplying apparatus based on the result of comparison by the comparing apparatus; and a detecting apparatus for detecting whether or not a detachable member whose attachment influences the detection of the toner concentration sensor is attached near the developing unit.

Abstract: A toner monitor in an electrostatographic machine is automatically calibrated when a new replaceable development station is loaded into the machine. The detected toner concentration in the development station is used by the monitor as a reference signal against which future readings are compared. The reference signal is reset upon machine power-up to correspond to the detected toner concentration in the development station, but only when there is a fresh development station in the machine. Resetting the reference signal only when there is a fresh development station prevents erroneous reference signals which would result if the developer mix concentration was other than perfect at power-down.

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 developing device for a copier is controlled such that if the rate at which toner is supplied into its developing tank is detected to exceed a preset reference value, stirring rollers for stirring the toner inside the developing tank are caused to rotate at a slower rate than if the toner supply rate is detected to be less than the reference value such that toner can be charged sufficiently in spite of its increased rate of supply and an image of good quality can be obtained.

Abstract: A developing apparatus for use in an electrophotographic system, which is so arranged that concentration of the developing material is maintained constant irrespective of the sizes of the sheets used for recording, and is not varied by the densities of the images to be recorded, while troubles of the apparatus, the state of "toner empty", and troubles of a developing material replenishing device, etc. may be detected without the need for providing sensors exclusive for the purpose.

Abstract: An apparatus for developing a latent image formed on a photoreceptor constituted a container for storing developer, a toner feeder for replenishing toner, a sensor for measuring the toner concentration in the developer, a memory for storing a reference measurement lying only with a certain range and which is obtained by measuring a reference developer having a reference toner concentration by the sensor, and a controller for controlling a toner concentration of the current developer by operating the toner feeder so that a current measurement obtained by the sensor becomes equal to the reference measurement.

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: An auto-toner sensor capable of performing an initial adjustment of the sensitivity of toner density detection automatically by means of a simple configuration is disclosed. The auto-toner sensor includes a sensor for detecting a toner density, and producing a sensor output signal indicating the detected toner density, the sensitivity of the sensor being adjustable by a control signal to be supplied to the sensor; a device for comparing a value of the sensor output signal with a prescribed reference value indicating an appropriate level of the toner density, to produce a comparison signal indicating a result of the comparison; and a device for producing in accordance with the comparison signal a control signal, to be given to the sensor, which adjusts the sensitivity of the detection of the toner density, the control signal having a value such that the value of the sensor output signal is substantially equal to that of the reference value when the toner has the density at the appropriate level.

Abstract: A toner replenishment control structure operates optimally for developer materials which exhibit toning contrast characteristics which vary predictably with the concentration of toner particles in the developer mix, and for developer materials which do not exhibit predictable changes in toning contrast as the toner concentration changes. An electrostatographic machine produces a contrast signal having a value proportional to toning contrast and a concentration signal having a value indicative of the ratio of toner to carrier in the mix, the concentration signal being substantially insensitive to the toning contrast. The system has a first state for actuating replenishment of toner of the first type according to the value of said contrast signal and a second state for actuating replenishment of toner of the second type according to the value of said concentration signal.

Abstract: A developing apparatus which includes a toner replenishing device for replenishing toner into the developing apparatus, a toner concentration detecting sensor for generating an output coresponding to the toner amount in a developing material stirred and transported through the developing apparatus, with the output containing a varying output periodically produced and stable output, a discriminating element for deriving the stable output of the outputs from the toner concentration detecting element, and a comparator for outputting a feeding signal to the toner replenishing device through comparison between the output from the discriminating element and a preliminarily set reference value.

Abstract: A device for detecting the density of a two-component developer consisting essentially of a toner and a carrier for an electrophotographic copying machine and the like comprises a cylindrical magnet and a sleeve which covers it. They rotate inside a developing tank so that the developer will flow in a layer on the sleeve surface. A baffle plate is provided to control this flow and to form a small pool of the developer where its density can be effectively measured by a sensor. The bottom end of the baffle plate near the sleeve surface is immersed in the developer inside the tank so that the motion of the developer into and out of the pool formed in the vicinity of the sensor is smooth and stable.

Abstract: A developing unit for electrophotography has a magnet roller disposed opposite to its photosensitive drum and a toner sensor disposed near the magnet roller and displaced from the position of one of the poles of the magnet roller by 5.degree.-15.degree. in the direction of the photosensitive drum.

Abstract: A method and apparatus for the rapid on-line coating of optical fibers with two-package polymer coating systems utilizing conventional liquid fiber coaters is described. The A and B parts of the two-package coating system are continuously combined and mixed together to form a polymerizable coating liquid as the fiber is drawn. This polymerizable coating liquid is continuously delivered to the liquid coater at a rate corresponding to the rate at which it is applied to the fiber, suitable control of the delivery rate being achieved via the use of a feedback signal to the coating liquid delivery system from, e.g., the fiber coater.

Abstract: A copier wherein charge director is supplied to a liquid developer in response to a conductivity measurement thereof. Toner concentrate deficient in charge director is supplied to the liquid developer in response to an optical transmissivity measurement thereof. Conductivity is measured by a pair of spaced electrodes immersed in the developer and through which a variable alternating current is passed. A variable capacitor neutralizes the inherent capacitance of the electrodes. A phase sensitive detector is provided with a reference voltage having the same phase shift as that caused by capacitive effects. The conductivity measurement is corrected in response to a developer temperature measurement.

Abstract: A control method of supplying toner to a developing device wherein a toner supply to the developing device is controlled so that a level of the toner density is increased in a range not more than a predetermined level at a predetermined interval of an integrated development period while the developing device continues its developing operations without any continuous interruption longer than a constant period, and the level of the toner density is decreased when the continuous interruption is longer than said constant period.

Abstract: A silicone-based composite coating system for a glass optical fiber, the system comprising a silicone polymer undercoating component and a silicone-polyimide block copolymer overcoating component, is provided. The coating system can be applied entirely on-line, improves the handling characteristics of the fibers over conventional silicone-coated fibers, offers an excellent combination of optical and elastic properties, and does not compromise the high-temperature operating characteristics of silicone-based coating systems.

Abstract: A toner solution circulation apparatus controls the application, concentration, and circulation by pumping of toner solution for an electrostatic imaging system by using a vacuum to draw toner solution, which is selectively mixed with concentrated toner solution and clear isopar, from a mixer manifold, and by using the rotating action of an applicator roll to pump, circulate, and mix toner solution, pigment, and isopar. A float and pivot block assembly maintains the correct isopar solution level in the chamber.A tube pump apparatus, having two tubes, one inside the other with sliding seals between the tubes, each tube having a ball type check (foot) valve at its end is submerged in concentrated toner solution in a supply container or bottle, to add pigment to the toner soltuion.The cycle time of the pump stroke is monitored by a Hall effect sensor.