Abstract: In a device for controlling the amount of toner replenished to a developing device depending on the density of a reference image formed on a photoconductor, if the toner density of a developer in the developing device fluctuates extremely; there may occur toner scattering, formation of coarse or rough images, and carrier attachment. To overcome those problems, a photosensor is disposed to detect the toner density in the developing device, and when an output of the photosensor is outside of a predetermined range, a target value to be compared with the detected density of the reference image is modified.

Abstract: A toner level detector assembly includes an electrically conductive container body that defines a container cavity and an orifice. A sensor assembly includes a holder and a probe. The holder is sealingly associated with the orifice. The probe is disposed within the holder. The holder electrically isolates the probe from the container body. The probe senses a level of material within the container cavity.

Abstract: In an electrophotographic image forming apparatus to which a cartridge containing a developer therein is detachably attachable, the cartridge has a memory storing therein information regarding the cartridge, and the main body of the apparatus is of a construction which has two or more devices for relating the output of a developer remaining amount detector and the developer amount to each other, and determines the method for relating the output of the developer remaining amount detector used to detect the developer amount from the output of the developer remaining amount detector and the developer amount to each other, on the basis of the information regarding the cartridge stored in the memory.

Abstract: In a detection unit, a measurement electrode member is arranged at a position where it contacts a developer, and has an input electrode for receiving a voltage from an apparatus main body and an output electrode for outputting an electrical signal in accordance with an electrostatic capacitance generated upon application of the voltage. A reference electrode member is arranged at a position where it does not contact the developer, and has an input electrode for receiving a voltage from the apparatus main body and an output electrode for outputting an electrical signal in accordance with an electrostatic capacitance generated upon application of the voltage. The measurement electrode member is adhered to an adhesion member. A lid member is coupled to the adhesion member and covers the reference electrode member. An engaging portion engages with a vessel positioning portion attached to the developer vessel, and positions the detection unit with respect to the developer vessel.

Abstract: In a developer container, there are provided a flat antenna for measuring the predetermined range of the developer-remaining-amount, and a plate antenna for measuring the predetermined amount or less of the developer-remaining-amount. When the detected value by the flat antenna is a predetermined value or greater, the minimum detected voltage value of the plate antenna is measured, and this value is stored as PAF (plate antenna full) in the storing means of a cartridge. During the measurement of the predetermined value or less of the developer by the plate antenna, the detected voltage value is calculation-processed and corrected by PAF to thereby obtain the developer amount.

Abstract: Toner (5) is measured in a toner cartridge (1) by compressing the air in the upper part (7) of the toner hopper (3). The result of the compression is observed by a diaphragm (13) or, alternatively, by a pressure transducer (25). The volume of air is inversely proportional to the resonant frequency of diaphragm (13) or the pressure at pressure transducer (25). This is converted by control system (23) using direct equations or table look-up of empirical data. The diaphragm (13) carries a magnet (15), which is driven by coil (19) from the imaging device and then frequency of current induced by magnet (15) is then sensed by coil (19). Uneven toner piling is not a significant factor in the results measured.

Abstract: A developing agent comprising a photocatalytic component is employed, wherein the developing agent is irradiated with predetermined light to decompose water molecule, thereby making it possible to prevent the electric charge of developing agent from being dissipated, which may be otherwise caused to occur due to the water that has been adsorbed onto the developing agent.

Abstract: A toner maintenance system for an electrophotographic developer unit, including a sump for storing a quantity of developer material comprised of carrier and toner material; a first member for transporting a mixture of developer material and toner particles from the sump, the first member having a voltage applied thereto; a metering blade, positioned closely adjacent to the first member to maintain the compressed pile height of the developer material on first member at a desired level; and a sensor device for measuring the current between the first member and the metering blade, and generating a signal indicative thereof.

Abstract: Provided is a method, system, and program for monitoring depletion of a consumable resource in a monitored system. Information is received on at least one unit of work to be processed by the monitored system, wherein the monitored system would deplete the consumable resource when processing each unit of work. A determination is made of a rate of resource depletion per unit of work processed. An amount of resource remaining after the monitored system processes the at least one unit of work is estimated as a function of the determined rate of resource depletion and a number of one or more units of work to process. A graphical display for rendering on a computer monitor is generated indicating the estimated amount of the resource remaining.

Abstract: A toner advisor apparatus and method for imaging systems includes an imaging device with a toner cartridge. More than one toner compartment in the toner cartridge is conformed to hold various toner colors. A cartridge scanner device is connected to the imaging system for scanning the more than one toner compartment. An analysis device is connected to the cartridge scanner device and to the imaging device for comparing the type of color required for a print job on the imaging device and the amounts of toner in the more than one toner compartment and for suggesting colors that optimize toner consumption. In one aspect of the invention, the analysis device is conformed to optimize toner consumption by suggesting colors that use nearly equal amounts of different toner colors over time.

Abstract: An image forming apparatus and method cause a connecting/conveying device to convey a recovered toner from a cleaner part to a recovered toner housing to house therein the recovered toner, and cause a controller to control a recovered toner supply and a new toner supply in accordance with a toner concentration ratio in a developing device, which is detected by a toner concentration ratio detector, to supply the recovered toner, which is stored in the recovered toner housing, and the new toner, which is stored in the new toner housing, to the developing device. The controller separately controls the recovered toner supply and the new toner supply in accordance with the contents detected by the toner concentration ratio detecting means, to cause to change the combination of the amounts of the recovered toner and new toner to be supplied to the developing device.

Abstract: A printer system calculates toner (or other marking agent) levels in a toner cartridge over an upper portion of the cartridge, while sensing toner levels in the remaining lower portion of the cartridge. The system provides the accuracy of a sensed toner environment when it is most needed, during the latter portion of a toner cartridge lifespan. A less accurate, but useful method of calculating the toner level is employed during the earlier stages of the toner cartridge lifespan. Thus, the system avoids the high cost associated with a completely sensed toner environment while providing the increased accuracy of a sensed toner environment when it is most beneficial to the system user.

Abstract: A developer container for containing a developer includes a detecting member for detecting a developer amount having an electrode member having a pair of input-side and output-side electrodes formed in parallel and in one plane at a predetermined interval and adapted to detect the capacitance between the electrodes, a measurement-side electrode that is in contact with the developer, and a reference electrode that is out of contact with the developer, the detecting member being provided on a side surface of the developer container. The container also includes a developer removing member for removing developer adhering to a detection surface of the detecting member, the developer removing member being attached to the developer conveying member and in contact with the detection surface of the detecting member so as to remove developer on the detection surface of the detecting member.

Abstract: A concentration controlling apparatus is provided for controlling the toner concentration of a developer contained in a developer unit. The developer contains a plurality of components including toner to be transferred to a photosensitive body for forming an electrostatic latent image. The concentration controlling apparatus includes a toner concentration detector for detecting the toner concentration of the developer, a supply determiner for determining a need for toner supply in response to detection output from the toner concentration detector, and a toner supplier for supplying a dose of the toner to the developer unit in accordance with the determination by the supply determiner. The supply determiner determines the need for toner supply at a higher toner concentration in a print-off state than in a print-on state.

Abstract: A developing device for developing an electrostatic latent image formed on an electrophotographic photosensitive member, includes a developing member for developing an electrostatic latent image formed on the photosensitive member with a developer, a detecting member for detecting the amount of developer, a stirring member for stirring the developer by rotation thereof, and a rubbing member for rubbing a surface of the detecting member. The rubbing member is a member separate from the stirring member and is rotatable integrally with the stirring member.

Abstract: A developer supplying apparatus includes a developer container containing therein a developer provided with a toner and a carrier, a developer bearing member for magnetically bearing and carrying the developer in the developer container to develop an electrostatic latent image formed on an image bearing member, a detector for detecting information corresponding to the density of the toner, and a supplying device for supplying the toner and the carrier to the developer container in conformity with the output of the detector. The intensity of an electric field for shifting the carrier from the developer bearing member to the image bearing member is greater than the intensity of an electric field formed between a nonimage portion of the electrostatic latent image formed on the image bearing member and the developer bearing member.

Abstract: A first embodiment of a measurement system provides an indication of performance of an electrophotographic process. The first embodiment includes a charge measurement device coupled to a developing device and a high voltage power supply. The charge measurement device generates a signal corresponding to the net charge transferred between the high voltage power supply and the developing device during an imaging operation. The measured charge transfer is compared to an estimated charge transfer to determine if the electrophotographic process is operating correctly. The estimated charge transfer is determined by multiplying an estimate of the mass of the toner transferred during an imaging operation by an average value of toner charge to mass ratio. A sufficiently large difference in the magnitude between the measured charge transfer and the estimated charge transferred indicates that the electrophotographic process is not operating correctly.

Abstract: This invention relates to a device for detecting when the magnetic toner in the developing unit of an image formation device is empty, and prevents erroneous detection of empty toner even when the fluidity of the magnetic toner becomes poor. The developing device (3) has a stirring unit (30) having a cleaning member (22) for cleaning the position of a toner sensor (10), a toner accumulation section (24), and a magnetic metal member (21). The magnetic metal member (21) and toner accumulation section (24) for preventing erroneous detection of the toner-empty alarm are located at the sensor position of the stirring unit, so it is possible for the toner sensor to synthetically generate output that toner is detected, and thus making it possible to prevent erroneous detection that the toner is empty.

Abstract: A printer system comprises a communication interface and printer components. The communication interface receives a humidity value from a toner cartridge. The printer components control printing operation based on the humidity value. To control printing operation, the printer components may configure a dither matrix based on the humidity value. The toner cartridge comprises a humidity sensor and a communication interface. The humidity sensor detects a humidity level and generates the humidity value to correspond to the humidity level. The communication interface transfers the humidity value from the humidity sensor to the printer system.

Abstract: A developing device includes a developer container which is mountable to an electrophotographic image forming apparatus main body, contains a developer for developing an electrostatic latent image formed on an electrophotographic photosensitive member, and includes a developer bearing member for carrying the developer to the electrophotographic photosensitive member, and a plurality of developer remaining amount detectors for successively detecting the remaining amount of developer within the developer container, wherein regions detected by the plurality of developer remaining amount detectors are overlapped with each other, and in the overlapped regions, a detected value by a previous developer remaining amount detector is changed over to a detected value by a succeeding developer remaining amount detector, and the apparatus main body detects the detected value to detect the remaining amount of developer.

Abstract: An image forming apparatus is provided with a function for forming an image on a recording medium such, as a sheet or the like. The image forming apparatus includes an image forming unit for forming an image on a recording material including an image bearing member. A developing unit develops an electrostatic image formed on the image bearing member by a developer. A density detection unit detects a developer density inside the developing unit. The density detection unit detects a parameter relating to physical property of the developer based on a previous detection value detected by the density detection unit during a previous image forming drive operation by the image forming unit and before the previous image forming drive operation stops. The detection unit also detects a next detection value detected by the density detecting unit after the previous image forming drive operation stops and before a next image forming drive operation by the image forming unit starts.

Abstract: A process cartridge detachably mountable to an electrophotographic image forming apparatus main body includes an electrophotographic photosensitive member, a process device acting on the electrophotographic photosensitive member, a measuring electrode member disposed in a part contacting developer and provided with an input side electrode and an output side electrode having at least a pair of portions disposed in parallel with a fixed interval, a reference electrode member disposed in a part not contacting the developer and provided with an input side electrode and an output side electrode having at least a pair of portions disposed in parallel with a fixed interval, an output contact for a measuring electrode electrically connected to the output side electrode of the measuring electrode member, an output contact for a reference electrode electrically connected to the output side electrode of the reference electrode member, and an input contact electrically connected to the input side electrodes of the measur

Abstract: A developer supplying apparatus includes a developer container containing therein a developer provided with a toner and a carrier, a developer bearing member for magnetically bearing and carrying the developer in the developer container to develop an electrostatic latent image formed on an image bearing member, a detector for detecting information corresponding to the density of the toner, and a supplying device for supplying the toner and the carrier to the developer container in conformity with the output of the detector. The intensity of an electric field for shifting the carrier from the developer bearing member to the image bearing member is greater than the intensity of an electric field formed between the non-image portion of the electrostatic latent image formed on the image bearing member and the developer bearing member.

Abstract: There is provided a toner supply method in a picture image forming system having a plurality of picture image forming parts, each of which is designed to supply a toner from a toner cartridge to a developing part, the toner supply method having the steps of: detecting a cartridge empty when the level of the toner in the toner cartridge of any one of the picture image forming parts becomes an empty level; introducing a toner, which remains in the toner cartridge of each of the plurality of picture image forming parts, from the toner cartridge of a corresponding one of the plurality of picture image forming parts into a reserve tank portion, which is provided so as to correspond to each of the toner cartridges for housing therein a predetermined quantity of toner, when the cartridge empty is detected in any one of the picture image forming parts; detecting a toner empty when the level of the toner in the developing part becomes an empty level in any one of the picture image forming parts; and inspiring to repla

Abstract: A developing device for use in an image forming apparatus has control means operatively responsive to receipt of an output signal of a first toner density detector means provided in a development unit for driving developing powder delivery means provided in a preliminary mixture/stirring unit to supply developing powder from a stirring chamber toward the development unit, while controlling regulator means so that introduction of the developing powder to the stirring chamber is inhibited at least within a developing powder refilling time period.

Abstract: The present invention relates to an image forming apparatus which has an image bearing member for bearing a latent image, charging device for charging the image bearing member by bringing ears of electrically conductive particles into contact with the image bearing member, developing device for visualizing the latent image formed on the image bearing member as a toner image by using a developer containing toner and carrier after the image bearing member has been charged by the charging device, a permeability of the carriers being different from a permeability of the electrically conductive particles, density control device for controlling density of the developer within the developing device, the density control device detecting a permeability of the developer, comparing a detected signal value based on the detected result with a reference value, and controlling the density of the developer on the basis of the comparison result, and reference value correcting device for correcting the reference value, the ref

Abstract: A developer container for containing a developer includes a detecting member for detecting developer amount which is an electrode member having a pair of input-side and output-side electrodes formed in parallel and in one plane at a predetermined interval and adapted to detect capacitance between the electrodes and which has a measurement-side electrode that is in contact with the developer and a reference electrode that is out of contact with the developer, the detecting member being provided on a side surface of the developer container, a developer removing member for removing developer adhering to a detection surface of the detecting member, the developer removing member being attached to the developer conveying member and in contact with the detection surface of the detecting member so as to remove developer on the detection surface of the detecting member, a developer conveying member for conveying the developer toward a developer bearing member, and an acting member acting by a torque of the developer r

Abstract: A developing device comprises a developer bearing member for bearing and conveying a developer having a toner and a carrier, a first magnetic pole arranged in the developer bearing member, a second magnetic pole arranged in the developer bearing member, a polarity of the second magnetic pole being opposite to a polarity of the first magnetic pole, and the second magnetic pole being adjacent to the first magnetic pole and arranged on a downstream side of the first magnetic pole in a moving direction of the developer bearing member, a regulating member for regulating a layer thickness of the developer borne by the developer bearer, the regulating member being arranged in the vicinity of the second magnetic pole and a concentration detector for detecting a concentration of the toner in the developer.

Abstract: A developing unit includes a photosensitive drum, a developing drum, and an agitator. When a charge of toner has dropped below a predetermined charging amount before a subsequent image foaming operation starts, a pre-driving operation is performed so that the developing drum and the agitator are rotated before a sheet feed operation stars. Therefore, sufficient charge can be applied to the toner before a developing operation starts, thereby providing a high-quality image. Also, because the photosensitive drum and the developing roller are separated from each other during the pre-driving operation, the photosensitive drum and the developing roller are prevented from being worn down.

Abstract: In conventional art, when a detected electrostatic capacity value of a point at which a developer container is full of a developer is larger or smaller than an initially set value, the developer residual amount is respectively estimated more or less than an actual amount since an output of antenna is sometimes influenced by an antenna tolerance. Therefore, it is provided an image forming apparatus in which a residual amount of a developer can accurately be detected and a cartridge which is detachably mountable on the image forming apparatus.

Abstract: A method of detecting a developer remaining amount for successively detecting the remaining amount of a developer used for developing an electrostatic latent image formed on an electrophotographic photosensitive member, the method including successively detecting the remaining amount of developer based on a period of time for which a light is blocked by a developer carried by a developer carrying member, wherein the developer is carried by the developer carrying member to a position in which the developer blocks the light that has entered a developer containing portion from a first light transmission opening of said a developer containing portion for containing the developer when the light transmitted from the first light transmission opening to an inside of the developer containing portion is transmitted from a second light transmission opening of the developer containing portion to an outside of the developer containing portion.

Abstract: A process cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus, includes a cartridge frame; an electrophotographic photosensitive member; a developer accommodating portion for accommodating a developer; a developing member for developing an electrostatic latent image formed on the electrophotographic photosensitive member with the developer; a developer feeding member for feeding the developer accommodated in the developer accommodating portion toward the developing member; and a developer amount detecting member, disposed along a movement path of the developer from the developer accommodating portion toward the developing member, for generating an electric signal for permitting the main assembly to detect substantially real time a remaining amount of the developer in the process cartridge, wherein the developer amount detecting member is disposed at and along an arcuate portion which is provided outside the cartridge frame along a path of rotational motion of th

Abstract: An image forming apparatus comprises an image bearer bearing a static image, an exchangeable type developing for developing the static image on the image bearer, the developing comprising a developing chamber having a developing roller in an opening opposite to the image bearer, and a containing chamber containing a developer to be supplied to the developing chamber, a detection electrode disposed outside the developing device and in which a voltage is induced, and a detection device for detecting an amount of the developer in the containing chamber on the basis of an induced voltage of the detection electrode.

Abstract: A process cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus includes an electrophotographic photosensitive member, a developing member, a developing device frame including a first frame portion supporting the developing member and a second frame portion having a developer accommodating portion, first and second spaced apart electroconductive portions to permit the main assembly to detect a remaining amount of developer in the process cartridge, a cartridge contact disposed in the second frame portion and electrically connectable to the main assembly when the cartridge is mounted to the main assembly, a contacting electrode disposed in the second frame portion and electrically connected with the cartridge contact, and a first electroconductive portion contact disposed in the first frame, electrically connected with the first electroconductive portion, and electrically contacting the contacting electrode at a connecting portion between the first and second frame

Abstract: To provide an image forming apparatus provided with a function for forming an image on a recording medium such as a sheet or the like.

Abstract: A developing device mounted on a main body of an electrophotographic image forming apparatus and adapted to develop an electrostatic latent image formed on an electrophotographic photosensitive member, includes a developer container which contains a developer therein and has a developer bearing member for feeding the developer to the electrophotographic photosensitive member in order to develop the electrostatic latent image formed on the electrophotographic photosensitive member, and N (N≧2) antenna electrodes for detecting the residual amount of developer within the developer container by detecting a variation of capacitance due to a developing bias voltage applied to the developer bearing member; wherein a projected area (S) and a distance (R) of the n-th antenna from the developer bearing member satisfy Sn−1≦Sn, and Rn−1≦Rn (2≦n≦N).

Abstract: A developing device mounted on a main body of an electrophotographic image forming apparatus and adapted to develop an electrostatic latent image formed on an electrophotographic photosensitive member includes a developer container having a developing portion with a developer bearing member for containing a developer and feeding the developer to the electrophotographic photosensitive member, and a hopper portion for containing the developer and supplying the developer to the developing portion, in order to develop the electrostatic latent image formed on the electrophotographic photosensitive member, and a developer residual amount detecting electrode pair having first and second electrodes disposed to interpose said developing portion and the hopper portion therebetween in order to detect the residual amount of developer by the main body of the electrophotographic image forming apparatus, wherein the developer residual amount detecting electrode pair are shaped such that a space region defined between the fi

Abstract: A device determines a quantity of product present in a reservoir, particularly a quantity of ink in the reservoir (112) of an image forming device, such as a printer (10). The device includes an electrode (120) disposed in contact with the product in the reservoir, a circuit (117) for supplying the electrode with an excitation signal (SE) causing an electromagnetic signal radiated by the product, a receiving antenna (116) for sensing the electromagnetic signal, and a circuit (115) for processing the electromagnetic signal sensed into a signal representing the quantity of product present in the reservoir.

Abstract: A developing device, a process cartridge and an electrophotographic image forming apparatus include a device for successively detecting the toner remaining amount throughout the service life of the process cartridge. A first antenna rod is provided on a rotating agitating member, and an amount of toner between them is detected successively. By using a second fixed antenna provided in a toner container, the toner amount is successively detected when the toner amount is small. A toner scraping-off member contacting the rotating agitating member is provided in the toner container.

Abstract: A method for detecting the status of the toner in a laser printer uses a photosensor. The method includes sampling a signal generated from the photosensor during a specified time, increasing or decreasing the value of a counter in accordance with an integral algorithm, and comparing the resultant counter value with a reference value, and displaying the status of the toner in the printer on a display device, depending on a result of such comparison. This method can accommodate relatively inexpensive photosensors. As the noise-ridden signal generated by such a photosensor is effectively filtered, this method is advantageous in cost and reliability.

Abstract: A toner concentration measuring method and apparatus by which the concentration of toner in solvent can be detected accurately with a simple construction without being influenced by a variation of the conductivity caused by a variation of the amount of ions in the solvent. A stepped dc voltage is applied from a high dc voltage generation section between a pair of electrodes placed in solvent, and very weak current which flows in a circuit formed from the pair of electrodes is measured by a current measuring section. The solvent between the pair of electrodes is replaced into an equivalent circuit, and a capacitance of the equivalent circuit is calculated in accordance with a circuit equation to determine the amount of ions in the solvent. Further, in accordance with a function expression wherein the ion amount and a resistance of the equivalent circuit are used as parameters, a toner concentration from which an influence of a variation of the amount of ions in the solvent is eliminated is determined.

Abstract: A developing device for developing an electrostatic latent image formed on an electrophotographic photosensitive member includes a rotatable developer bearing member bearing a developer thereon, a developer regulating member for regulating the amount of the developer born on the developer bearing member, a first rotatable developer conveying member for conveying the developer toward the developer bearing member, and a second rotatably developer conveying member. A developer-remaining-amount detecting member for detecting the amount of remaining developer is disposed in an area defined by the tangential lines of a first circle and a second circle as the loci of rotation of the first developer conveying member and the second developer conveying member as viewed from the longitudinal direction of the developer bearing member.

Abstract: A toner content control device for an electrophotographic apparatus of the type using a toner and carrier mixture. The control device determines an amount of toner replenishment on the basis of a difference between the toner content of the developer and a reference value, while correcting the reference value in accordance with the condition of a reference pattern formed on a photoconductive element. Although the control device includes a toner content sensor and a pattern density sensor, it omits conventional means for adjusting the toner content sensor. The control device is therefore capable of controlling image density stably with an inexpensive configuration.

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: A developing cartridge for developing a latent image formed on the photosensitive member, wherein the developing cartridge is detachably mountable to a main assembly of an electrophotographic image forming apparatus, the developing cartridge includes a cartridge frame; a developing member for developing a latent image formed on the photosensitive member; a driving force receiving member for receiving driving force for rotating the developing member from the main assembly of the apparatus when the developing cartridge is mounted to the main assembly, the driving force receiving member being exposed from a portion of the cartridge adjacent one longitudinal end of the developing member; a developing bias contact for receiving a developing bias to be applied to the developing member from the main assembly when the cartridge is mounted to the main assembly; a toner accommodating portion for accommodating the toner to be used for development by the developing member; a first light-transmissive member and a second l

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 forming apparatus includes an image bearing member and a charging unit having magnetic particles that are contactable with the image bearing member. An electrostatic image forming unit forms an electrostatic image on the charged image bearing member. A developing device develops an electrostatic image on the image bearing member with toner that includes toner and magnetic carrier. A detecting unit detects the toner content of the developer and a toner supply unit supplies the toner into the developing unit when the detected toner content is lower than a predetermined level. A calculating unit calculates the changing rate of the toner content from an output of the detecting unit and a warning unit warns that a changing rate of the toner content is larger than a predetermined level.

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: An image forming apparatus including an image bearing member, a latent image forming device which forms a latent image on the image bearing member, a developing device which develops the latent image using a two-component developer including a toner and a carrier and a toner supplying device which supplies toner into the developing device. A developer agitating device agitates developer in the developing device and a toner-density detecting device detects a toner density of developer in the developing device. A toner-density control device controls the toner density by operating the toner supplying device on the basis of a detected result according to the toner-density detecting device. A memory device stores resultant value of the toner density detected by the toner-density detecting device during image forming operations. The toner-density detecting device detects the toner density in a warm-up operation before starting the image forming operation by the image forming apparatus.

Abstract: In order to detect a toner density in a liquid developer accurately while lowering the influence of ions on the liquid developer, the toner density detecting apparatus 11 detects a toner density in a liquid developer obtained by mixing charged toner particles in a carrier solution. The first and second electrodes 12 and 13 are opposed to each other with a liquid developer therebetween and connected to the first DC power source (V.sub.1) thereby to apply the first electrical field to the liquid developer. The toner density detecting apparatus 11 further includes the third and fourth electrodes 14 and 15 opposed to each other in the direction orthogonal approximately to the direction in which the first and second electrodes 12 and 13 are opposed to each other and connected to the second power sources (V.sub.2, V.sub.3, V.sub.4) thereby to apply the second electrical field.