Abstract: A development unit for a reproduction apparatus wherein the development unit contains marking agents by means of which prints are made. As a result of making prints, the quantity of marking agents in the development unit decreases. If this quantity decreases below a specific level, then marking agents are fed from a reservoir to the development unit. If at a specific moment circumstances result in a large quantity of marking agents being consumed in a short interval of time, then since resupplying the development unit takes some time there is a momentary a shortage of marking agents in the development unit which is undesirable. By supplying marking agents when a gradient of toner consumption exceeds a specific value, a future shortage is anticipated and the occurrence of a situation in which a shortage of marking agents occurs is considerably reduced.

Abstract: An electrophotographic image generation device such as an electrophotographic printer comprises an image bearing belt, a development section, a toner image transfer section, a toner concentration sensor, and an electrical charge control section. A latent image due to variations in electric potential is formed on the image bearing belt by irradiation of photo image light. The development section applies a liquid developing agent on the surface of the image bearing belt and thereby changes the latent image into a visible toner image. The toner image transfer section transfers the toner image on the surface of the image bearing belt to the surface of a sheet and thereby executes printing to the sheet. The toner concentration sensor detects the concentration of toner particles in the liquid developing agent.

Abstract: An image forming apparatus includes an image bearing member, a latent image forming device that forms a latent image on the image bearing member, a developing device that develops latent image on said image bearing member to a toner image with a two-component developer, and a toner density detecting device that detects toner density of the two-component developer in which the toner image is formed and outputted as a visible image onto a transfer member. A control device is provided for agitating the developer for a predetermined time period during an initial setting is performed for the developer, detecting a toner density of said developer after the predetermined agitation, and performing an abnormal process when a result of the detection is out of the predetermined range.

Abstract: An image recording apparatus includes a photosensitive drum on which an electrostatic latent image is formed by laser beam irradiation from an optical unit. A developing unit, which receives toner from a toner feeder and is provided with a toner agitator, supplies toner onto the drum for converting the latent image to a visible image. A toner sensor detects the concentration of the toner within the developing unit for output of a corresponding detection signal. A toner supply controller controls the toner feeder by comparing the output of the toner sensor with a varying standard voltage which varies linearly from a peak level to a steady level. An exposure start controller causes the optical unit to start irradiating the photosensitive drum with light after the rotation of the drum is stabilized but before the output of the toner sensor reaches the peak level.

Abstract: A control apparatus for controlling a concentration of a solute having a predetermined optical absorption characteristic is disclosed. A cell holding member has a plurality of cells formed therein, one of which is placed at a predetermined detection position so that the solution flows through that cell. A concentration of the solute is detected based on the intensity of light that has passed through the cell placed at the predetermined detection position. A cell changer replaces the cell with another cell by moving the cell holding member when a detected concentration has not changed as expected.

Abstract: A method for detecting a toner concentration of a liquid developer including toner particles and carrier liquid is disclosed. The carrier liquid is separated from the liquid developer and a developer electrical conductivity and a carrier liquid electrical conductivity are detected. The toner concentration is detected based on a difference of the developer electrical conductivity and a carrier liquid electrical conductivity.

Abstract: An image forming device includes an optical system for forming an electrostatic latent image on a photosensitive body by exposure of an original in light, a development system for developing the electrostatic latent image, and a control system for controlling the optical system and the development system. The control system detects the concentration of a toner in a developing agent tank, calculating a difference between the detected toner concentration and a predetermined toner concentration, replenishing the toner to the developing agent tank until the detected toner concentration makes a recovery to the predetermined toner concentration, clocking a time period for the recovery and controlling at least one of the amount of the exposure light and the amount of the toner adhering to a photosensitive body based on the clocked time period for the recovery.

Abstract: There is provided a developing agent replenishing method in a digital photographic printer in which an image is exposed onto a photosensitive material based on digital data containing image data and the exposed photosensitive material is developed by a developing agent, comprising the steps of: (a) calculating an image rate of an image to be exposed based on the digital data, the image rate being a parameter for obtaining, based on at least one of a density characteristic of the image to be exposed, depth of the image to be exposed, and contrast of the image to be exposed, a replenishment quantity of a developing agent used for development processing of the image to be exposed; (b) calculating a replenishment quantity of the developing agent based on the calculated image rate; and (c) effecting replenishment of the developing agent on the basis of the calculated replenishment quantity.

Abstract: An image forming apparatus which is capable of adjusting toner density in response to variations of humidity. The image forming apparatus includes a toner density detector that detects the density of toner inside an image developer, a humidity detector that detects toner humidity inside the image forming apparatus, and a controller that controls a toner supplier on the basis of the toner density detected by the toner density detector and that adjusts the toner density in accordance with variations of humidity detected by the humidity detector. The humidity detector is located at a position where the humidity detector can detect humidity of air around the image developer and where the humidity detector is minimally affected by heated air.

Abstract: A method and a system for optically detecting an empty condition in a toner cartridge has a light reflector placed on an outside surface of a toner cartridge wall. A light source emits light directly or ultimately towards the light reflector and the reflected light is detected by a light detection device if the toner cartridge is sufficiently empty.

Abstract: A toner density controlling apparatus adapted to control toner density by sensing a T/D level in a developer vessel by using a toner sensor performs a toner density controlling operation on the basis of an output of the toner sensor while maintaining an input control voltage to be applied to the toner sensor at a predetermined level in a definite control range where the toner sensor output decreases proportionally to the T/D level in a linear relation. Conversely, in an indefinite control range where the relationship between the toner sensor output and the T/D level is nonlinear, the input control voltage to be applied to the toner sensor is variably controlled so that the toner sensor output can be adjusted to an upper or lower limit level of the definite control range, and the toner density controlling operation is performed on the basis of the input control voltage.

Abstract: There is provided an image forming device capable of preventing smudges on the background of an image due to excess toner replenishment caused by a failure in stirring developer and toner enough to charge the toner or scattering of replenished toner without being charged. A toner conveying member for conveying replenished toner from a toner replenishing portion through a toner replenishing port to a developer stirring and conveying member is constructed by a screw member unitarily formed with the developer stirring and conveying member. The screw member has a spiral conveying fin capable of conveying the replenished toner at relatively high speed. The replenished toner is delivered to a toner replenishing portion provided in the upstream of a developer receiving portion of the screw member.

Abstract: The image forming apparatus of the invention controls the toner density by any one of the following configurations: by correcting the toner density of the developer in association with the agitation total; by controlling a process parameter so that the density of a toner patch formed on the photoreceptor corresponds to a prescribed density value and determining that developing performance of the developer is improved and canceling the toner density correction when the process parameter reaches the prescribed value; by changing the toner density reference value when the variation as to the charger output is equal to or greater than a first predetermined value and maintaining the changed toner density reference value until the variation of the charger output again becomes equal to or greater than the first predetermined value; or by prohibiting toner supply for a constant duration to prevent excessive toner supply if time from the end of the last operation of the developing unit to the start of a next operation

Abstract: In an imaging machine including an imaging member, operating components including a toner dispense system including a source of toner material and a dispenser for transferring toner material from the source to a developer device to replenish the developer device with toner material, and a control to provide images on copy sheets, a smart sensor system including a sensor, a toner concentration reference, and a filter. The sensor provides signals representing the toner concentration and the filter interconnected to the sensor and to the toner concentration reference reduces error in the signals representing the toner concentration. A comparator responding to the toner concentration reference and the filter signals provides an error signal to the control system in turn providing a toner dispense signal.

Abstract: A method and an apparatus for measuring the toner concentration and the amount of electric charge, capable of simultaneously measuring the toner concentration and the amount of electric charge easily and maintaining high precision using a simple device.

Abstract: A toner near empty discriminating unit discriminates a near empty indicating that the toner approaches an empty state on the basis of a detection value of a toner sensor. When the toner near empty is determined, a toner supply amount calculating unit calculates a toner supply amount (w) per time as w=W/X from the number (X) of toner supplying times of a toner supply counter and a specified toner filling amount (W) when a toner cartridge is set. On the basis of the calculated toner supply amount (w) of one time, a correction processing unit corrects a rotational speed of a supply roller of a toner supply control unit and an operation time of the supply roller, or the number of discriminating times of the toner empty and the number of discriminating times of a replacement of an expendable item.

Abstract: A method adjusting toner concentration in a printing machine by first reading a first clean imaging surface reflectance value from a segment of the imaging surface with the developer in an off mode and storing the reflectance value as a reference. A second clean imaging surface reflectance value from the same segment of the imaging surface is then read with the developer in an on mode. The first clean imaging surface reflectance value is compared to the second clean imaging surface reflectance value and the toner dispenser is controlled in response to the difference.

Abstract: A toner monitor particularly suited for monitoring toner concentration in a two-component development mixture includes an electrically conductive probe mounted in a wall of a development apparatus but the probe does not extend substantially into the developer mixture. A square wave generator or other multifrequency signal source generates a first signal so that electromagnetic energy is carried along the probe and into the mixture. A second signal is generated in response to an impedance mismatch between the mixture and the probe. In response to the second signal, a third signal is generated relating to adjustment of composition content of the development mixture.

Abstract: An image forming apparatus includes a developer container comprising toner particles and carrier particles. A developer carrying member is disposed in the developer container, for carrying the developer to a developing zone where an electrostatic latent image is developed. A first toner container contains toner particles, and a first supply mechanism supplies toner particles from the first toner container to the developer container in response to a toner supply signal, to maintain a ratio of toner particles to carrier particles constant. A second toner container contains toner particles, and a second supply mechanism supplies toner particles from the second toner container to the first toner container, to maintain the amount of toner particles in the first container constant.

Abstract: A developer unit of the present invention has an agitating paddle which agitates a developer containing a magnetic carrier and a non-magnetic toner, and a toner is supplied from the toner hopper according to an output of a toner concentration sensor. After an agitation is finished which is performed when the power is turned on, the agitating paddle is periodically operated to agitate the developer. During the agitation, a toner concentration controller shifts a reference level with which the output of the toner concentration sensor is compared from a predetermined level to a higher level and then stepwisely returns it to the predetermined level.

Abstract: A recycle developing method utilizes the steps of (1) providing a developing vessel containing a starting developer composed of an electroscopic toner and a magnetic carrier; (2) transferring toner from the developing vessel to a photosensitive material having an electrostatic latent image formed thereon; (3) transferring a portion of the toner on the photosensitive material to a paper to form a toner image on the paper; (4) recovering toner remaining on the photosensitive material after the aforementioned portion of toner is transferred to the paper to form a toner image thereon; and (5) repeating steps (2)-(4) while replenishing toner in the developing vessel by the sub-steps of: (5a) supplying toner recovered in step (4) to the developing vessel, and (5b) supplying a virgin toner, having a higher chargeability than the electroscopic toner in the starting developer, to the developing vessel, to form a mixed toner in the developing vessel.

Abstract: In an image forming apparatus, a latent image is electrostatically formed on a photoconductive element and then developed by a developing unit. The developing unit is formed with a used toner inlet for receiving used toner. A cleaning unit removes toner remaining on the photoconductive element after image transfer and thereby collects it as the used toner. A conveying device conveys the used toner from the cleaning unit to the used toner inlet of the developing unit. A toner end sensor is disposed in the developing unit and adjoins the used toner inlet. On determining that the amount of toner existing in the developing unit is less than a predetermined amount, the sensor causes fresh toner to be replenished into the unit.

Abstract: An apparatus for controlling the concentration of toner within a developer material of carrier and toner. The apparatus having a magnetic roll for transporting a combination of carrier material and toner particles, a donor roll for transporting toner particles from said magnetic roll to a photoreceptor transfer zone, the magnetic roll and the donor roll each having a voltage applied thereto. A sensor measures the dynamic current between the magnetic roll and the donor roll and generates a signal as a function thereof. The dynamic current between the magnetic roll and the donor roll is a function of the concentration of the toner particles and the carrier material. As a result of the sensor output signal toner particles are added to the developer sump to maintain proper triboelectric properties within the developer unit.