Abstract: According to one embodiment, a developing device forms a toner image on a photoconductive image carrier with toner supplied from a toner cartridge. A toner concentration sensor detects a toner concentration in the developing device. A toner supply motor supplies the toner from the toner cartridge to the developing device based on the toner concentration. A processor detects an empty toner based on a toner supply rate, a print rate of the image data, and toner characteristics that are characteristics of the toner supplied from the toner cartridge to the developing device, the toner supply rate being calculated based on a pixel count value that is an integrated value of pixel values of the image data and a toner supply motor count value that is an integrated value of drive times of the toner supply motor.

Abstract: A carrier for developing an electrostatic charge image has magnetic particles and a resin coating that covers the magnetic particles and contains at least one lubricant. The resin coating has a dispersed phase of the lubricant and meets requirement (1). Requirement (1): the lubricant content in a top layer>the lubricant content in a middle layer>the lubricant content in a bottom layer The top, middle, and bottom layers are of the resin coating divided into three in the direction of thickness, and the lubricant content is the percentage area of the dispersed phase of the lubricant in a cross-section of the layer taken along the thickness thereof.

Abstract: In a toner case attachable to and detachable from a case storage portion of an image forming apparatus, a case main body is long in an attachment direction with respect to the case storage portion, and includes lower and upper housings defining lower and upper spaces among its inner space. Rims of upper-surface opening of the lower housing and lower-surface opening of the upper housing are joined together. A ceiling surface of the case storage portion is inclined diagonally upward from upper end of one side wall of the case storage portion toward the other opposite side wall in the width direction. The upper housing includes an inclined portion inclined corresponding to the inclined surface. When the case main body is attached to the case storage portion, the joint portion of the lower and upper housings has approximately the same height as the upper end of the side wall.

Abstract: A developing device includes a developing container, a feeding member, a developer carrying member, and a collecting device. A coverage which is a percentage of coating of surfaces of the carrier particles with the toner particles is 100% or more and 200% or less. The developer carrying member has a plurality of recessed portions formed on a surface thereof so that at least the toner particles having an average particle size are contactable with inner surfaces of the recessed portions, and the carrier particles having an average particle size are not contactable with the inner surfaces of the recessed portions. The recessed portions are formed so that not less than half of the toner particles having the average particle size are exposed from the recessed portions when the toner particles having the average particle size enter the recessed portions.

Abstract: A method for programming memory of a replaceable unit of an electrophotographic image forming device according to one example embodiment includes determining an amount of toner in a reservoir of the replaceable unit. The amount of toner determined is converted to an estimate of an amount of rotation of a shaft that will be sensed before the reservoir of the replaceable unit runs out of usable toner. The estimate of the amount of rotation of the shaft that will be sensed before the reservoir of the replaceable unit runs out of usable toner is stored in the memory of the replaceable unit.

Abstract: An image forming apparatus includes a development section, a toner replenishment section, a toner sensor, and a determination section. The new toner container is filled with first and second toners that have different magnetic characteristics. The new container supplies the first toner to the toner replenishment section prior to the second toner. The determination section determines replacement of an existing toner container by a new one upon the output value of the toner sensor changing from a value out of a first-toner output value range to a value therewithin. The first-toner output value range is a range of an output value of the toner sensor in response to the magnetic characteristic of the first tone.

Abstract: A developing device includes a developer carrying member for carrying a developer comprising a toner and a carrier, a magnet provided inside the developer carrying member, a developing chamber for feeding the developer to the developer carrying member, and a feeding member rotatably provided in the developing chamber for feeding the developer in the developing chamber. A non-magnetic blade member regulates an amount of the developer to be coated on said developer carrying member, and a route forming portion forms a route for feeding a developer in the developing chamber. The magnet is opposed to a region inside of the developer carrying member from a downstream end of an opposing portion to the blade member with the rotational direction of said developer carrying member so as to attract the developer on the region.

Abstract: A developing device includes a developer container, a developing unit, a developer outlet and a replenishment developer inlet. The developer container contains a developer composed of a toner and a first carrier. The developing unit develops an electrostatic latent image on an image carrier using the developer. The developer outlet discharges the developer. The replenishment developer inlet supplies a replenishment developer to the developer container. The replenishment developer includes a second carrier. A ratio of a poured bulk density of the second carrier to a poured bulk density of the first carrier ranges from 1.05 to 1.65.

Abstract: A developing device includes: a developer container section configured to contain therein a two-component developer composed of toner and magnetic carrier; a developer bearing member configured to supply the developer to an image bearing member on which an electrostatic latent image is formed; a toner supplying section configured to supply the toner to the developer container section via the toner supply port; a carrier supplying section provided separately from the toner supplying section, the carrier supplying section being configured to supply the carrier to the developer container section via the carrier supply port; and a carrier detection section disposed at a position near the carrier supply port and at a same level as a powder surface of the developer contained in the developer container section, the carrier detection section being configured to detect carrier supplied from the carrier supplying section.

Abstract: An image forming apparatus includes: a toner supply section that supplies toner to a plurality of developing sections; a carrier supply section that supplies carrier to the plurality of developing sections; and a control section that controls an operation of the carrier supply section. The carrier supply section includes: a carrier housing section; a carrier distributing section that receives a predetermined amount of carrier that has freely fallen from the carrier housing section and guides the predetermined amount of carrier to each of the plurality of developing sections; a support frame section that slidably supports the carrier distributing section; and a vibration exciter section that vibrates the carrier distributing section.

Abstract: A developing device includes a developer carrying member for carrying developer containing a non-magnetic toner and a magnetic carrier to a position where the developer carrying member is opposed to an image bearing member, and a developing container including a first chamber for accommodating the developer to be supplied to the developer carrying member, a second chamber provided below the first chamber, and an opening for circulating the developer between the first chamber and the second chamber. In addition, a first feeding member and a second feeding member are rotatably provided in the first chamber and the second chamber, respectively, for stirring and feeding the developer.

Abstract: An image forming method that can obtain a high fixing strength and reduce the occurrence of a document offset phenomenon is provided. In the image forming method the polyester resin forming the binder resin of the toner is obtained by condensing and polymerizing a carboxylic component containing at least one compound selected from chemical formula (1), (2) and (3) shown below that is an addition reactant of abietic acid and a carboxylic compound having an unsaturated double bond and an alcohol component, and the content of at least the one compound selected from the chemical formula (1), (2) and (3) in the carboxylic component is 5% by mass or more, and the fixing agent contains an alkylene carbonate which may have a substituent group or an aliphatic alkyl carboxylic acid ester which may have a substituent group.

Abstract: A developing device includes a developer container, a developing unit, a developer outlet and a replenishment developer inlet. The developer container contains a developer composed of a toner and a first carrier. The developing unit develops an electrostatic latent image on an image carrier using the developer. The developer outlet discharges the developer. The replenishment developer inlet supplies a replenishment developer to the developer container. The replenishment developer includes a second carrier. A ratio of a poured bulk density of the second carrier to a poured bulk density of the first carrier ranges from 0.60 to 0.95.

Abstract: A developer case includes a case main body and a carrier tank. The case main body includes a toner containing space and a merging space. The toner containing space contains a toner. The merging space communicates to the toner containing space. The carrier tank is attachably/detachably installed to the case main body. The carrier tank includes a carrier containing space. The carrier containing space contains a carrier and communicates to the merging space. The toner conveyed from the toner containing space and the carrier conveyed from the carrier containing space are merged with each other in the merging space and discharged to an outside.

Abstract: An electrostatic charge image developer includes a toner for developing an electrostatic charge image, containing toner particles including a polyester resin having a rosin skeleton and an external additive, and a carrier having core material particles and a coating resin layer which coats the surface of the core material particles, in which the hardness of the coating resin layer is from 1.2 times to 2.0 times that of the toner particles.

Abstract: The invention discloses a processing cartridge, which includes a powder tube, a sliding member and a mechanism for holding the sliding member, wherein the powder tube is used for receiving toner and the sliding member is capable of freely sliding in the powder tube. The mechanism for holding the sliding member is driven to close a powder outlet under the non-use state and a powder outlet portion is arranged on the powder tube. The powder outlet is arranged on the powder outlet portion and the sliding member closes the powder outlet under the action of the mechanism for holding the sliding member under the non-use state, and moves under the action of an external force to open the powder outlet under the use state. An internal member provided with an internal powder feeding opening is also arranged inside the powder outlet portion.

Abstract: A developing device including a two-component developer including toner and a carrier. The developing device includes first and second developer housing portions divided by a barrier wall having first and second communication openings. A development member is disposed on the first developer housing portion, and first and second agitators are respectively disposed on the first and second developer housing portions. The developing device satisfies 1.8?(Wa/Wb)?3.0, wherein Wa represents a mass of the developer in the first developer housing portion and Wb represents a mass of the developer in the second developer housing portion at an equilibrium state.

Abstract: Apparatus for maintenance of ink concentration stability in a reservoir (12) of a solid ink add printing device (10) over the course of a printing operation, comprises: a look-ahead unit (24) which looks at incoming printing instruction data (22) to determine pending ink usage, and a dynamic feed mechanism control unit (18) to dynamically control the feeding mechanism to modify feeding of the ink particles based on the determined pending ink usage.

Abstract: A developing device includes a developer carrying member; a first feeding path in which a developer is to be supplied and fed to the developer carrying member at a position in which the first feeding path opposes the developer carrying member; a second feeding path, communicating with the first feeding path, for forming a circulation path with the first feeding path; a discharge opening for permitting discharge of an excessive developer in the developing device; a first supply opening, located downstream of the first feeding path opposing the developer carrying member with respect to a developer feeding direction and located upstream of the discharge opening with respect to the developer feeding direction, for permitting supply of a first developer containing at least toner; and a second supply opening, located upstream of the first feeding path with respect to the developer feeding direction and located downstream of the discharge opening with respect to the developer feeding direction, for permitting supply

Abstract: The developer supplying device supplies a supplementary developer including a toner and a carrier in a predetermined weight ratio. The developer supplying device includes a supplementary developer container containing the supplementary developer, and a supplementary developer feeding passage configured to feed the supplementary developer from the supplementary developer container to a developing device. The supplementary developer container is replaced when the supplementary developer is substantially exhausted. The developer supplying device further includes a carrier concentration determining device provided on the supplementary developer feeding passage to determine the concentration of the carrier in the supplementary developer fed through the supplementary developer feeding passage, and a residual supplementary developer amount estimating device configured to estimate the amount of the supplementary developer remaining in the supplementary developer container.

Abstract: A two component developer storage product to replenish a two component developer containing at least toner and carrier includes: a cylindrical container having an opening at one end thereof; a lid to close the opening; a toner layer stored in the cylindrical container; and a carrier layer stored in the cylindrical container; wherein the toner layer and the carrier layer are stacked, and the cylindrical container has a spiral projection on an inner spherical surface thereof, and is configured such that when the cylindrical container is rotated, the toner layer and the carrier layer are conveyed by the spiral projection and toner and carrier are discharged from the opening.

Abstract: An image forming apparatus having a development apparatus that includes: a developer storing part; a developer supply mechanism; and a surplus developer removing section; wherein the developer supply mechanism includes: a toner storing part; a carrier storing part; a developer conveying path and a conveying mechanism, both are arranged between the toner storing part and the developer storing part, and between the carrier storing part and the developer storing part; wherein the developer conveying path includes a toner ejection outlet through which a toner stored in the toner storing part is ejected and a carrier ejection outlet through which a carrier stored in the carrier storing part is ejected, and a supplying developer ejection outlet through which a supplying developer is ejected to the developer storing part; and wherein the conveying mechanism is adapted to convey the toner and the carrier while stirring them.

Abstract: A development device to develop a latent image with two-component developer includes a developer carrier disposed facing the image carrier, to carry the developer, a magnetic field generator disposed inside the developer carrier, to form multiple magnetic poles around the developer carrier, an interior wall dividing the interior of the development device into a first transport chamber and a second transport chamber parallel to the first transport chamber, a first transport member disposed in the first transport chamber, facing the developer carrier, to supply the developer to the developer carrier while transporting the developer longitudinally, a second transport member disposed in the second transport chamber, facing the developer carrier, to transport the developer separated from the developer carrier longitudinally, a partition disposed between the developer carrier and the second transport member to prevent resupply of the used developer in the second transport chamber from to the developer carrier.

Abstract: According to an embodiment, a developing device, comprising: a developing unit configured to store an initial two-component developer including an initial toner containing silica externally added and a carrier and to form a toner image on an image bearing member with the two-component developer; a discharging section configured to discharge a part of the initial developer from the developing unit; and a developer supplying unit configured to supply a supply developer including a supply toner containing silica externally added and the carrier to the developing unit, the amount of silica added to the supply toner being smaller than the amount of silica added to the initial toner.

Abstract: An image forming apparatus includes an image bearing member for bearing an electrostatic latent image; a charger for electrically charging the image bearing member by contact of electroconductive magnetic particles carried on a magnetic particle carrying member with the image bearing member; a developing device for developing the electrostatic latent image into a toner image by supplying toner to the electrostatic latent image; a layer thickness detecting device for detecting a thickness of a surface layer of the image bearing member; a supplying device for supplying the magnetic particles to the magnetic particle carrying member with predetermined timing; and a control device for controlling a supply amount of the magnetic particles so that the supply amount of the magnetic particles supplied by the supplying device increases with an increase of an amount of change in thickness, in terms of an absolute value, of the surface layer obtained from a detection result of the layer thickness detecting device.

Abstract: A developing device includes a container storing a two-component developer including a toner and a carrier, a toner carrying body carrying the toner in the container and supplying the toner to a predetermined image carrying body by rotation, a restricting member held in press contact with the toner carrying body, and a restricting nip section formed between the toner carrying body and the restricting member. The restricting nip section selects only the toner in the two-component developer to form a uniform toner layer on the toner carrying body.

Abstract: A method for loading a replenishment developer into a developer accommodating container such that when the replenishment of the replenishment developer inside the loaded developer accommodating container is started, the developer composed of a toner and a carrier, or a toner is discharged from a developer discharge port of the developer accommodating container, wherein when a premix toner that is a replenishment developer composed of a replenishment toner and a replenishment carrier is loaded into a toner bottle serving as the developer accommodating container, the replenishment carrier is loaded and then the replenishment toner is loaded.

Abstract: A developing device and an image forming apparatus which can form a printing image having high resolution and a high quality level, while resolving various problems resulted from the use of small particle size toner particles are provided. The developing device includes a toner constituted of resin base particles containing a coloring agent and a binder resin, and silicone oil and/or fluoro oil added to the resin base particles, a toner receiving portion for receiving the toner, and a developing roller having an outer peripheral surface and an irregularity section for carrying the toner, the irregularity section formed on the outer peripheral surface and including a plurality of depression portions and/or protrusion portions provided regularly and uniformly, wherein an average particle size of the resin base particles in volume basis is in the range of 2 to 4 ?m, and an added amount of the silicone oil and/or fluoro oil to the resin base particles is in the range of 0.05 to 2 mass %.

Abstract: A developer container that contains a two-component developer including a carrier and toner includes a developer containing portion configured to include a plurality of surfaces and to accommodate the two-component developer and a cap configured to communicate to a suction pump so that the two-component developer is sucked by the suction pump and is conveyed to a developing unit. The developer containing portion is configured to include an internal space having at least 12% of an air space measured after the two-component developer is packed in the developer containing portion and left still for at least 24 hours.

Abstract: A toner bottle containing a cylindrical toner container having therein a toner comprising at least a resin, a colorant and an external additive, the toner container having a toner discharge port on an end thereof and a rotation axis along the cylindrical toner container, and the toner container being installable in an image forming apparatus, wherein the toner container has plural protrusions which are intermittently provided in an interior of the cylindrical container, the protrusions having a function to convey the toner toward the toner discharge port when the toner container is rotated around the rotation axis; an X-ray intensity ratio of titanium to silicon (Ti/Si) determined via X-ray fluorescence spectrometry of the toner is 1.0 to 3.0; and a conveyance index of the toner is 2.0 to 10.0 mg/sec.

Abstract: A developer supply system includes a container, a memory, and a positioning mechanism. The container has a deformable bag formed of flexible material to accommodate developer therein. The memory is attached to a given planar surface of the deformable bag to store information for communication to the image forming apparatus. The positioning mechanism holds the container therein while maintaining the given planar surface in position relative to the image forming apparatus when the deformable bag collapses as it discharges developer. An image forming apparatus employing such a developer supply system is also disclosed.

Abstract: A toner cartridge provided in an image forming apparatus in a removable manner for supplying toner to the image forming apparatus, the cartridge comprises a toner cartridge main body which contains the toner, a discharging opening for supplying the toner contained in the toner cartridge main body to the image forming apparatus and a shutter which opens the discharging opening when the toner cartridge main body is inserted in the image forming apparatus and closes the discharging opening when the toner cartridge main body is removed from the image forming apparatus, wherein the shutter has a concave part formed therein for engaging with a holding member which holds the shutter provided in the image forming apparatus to open and close the discharging opening when the toner cartridge main body is inserted in or removed from the image forming apparatus.

Abstract: An aspect of the invention provides an image forming unit that comprises: a developer container configured to contain a developer; and a developer supplier including at least a developer carrier configured to supply the developer, contained in the developer container, to a latent image formed on an image carrier, wherein: the glass transition temperature of a first developer initially contained in the developer supplier is higher than the glass transition temperature of a second developer contained in the developer container; and the glass transition temperature of the first developer is equal to or lower than 75° C.

Abstract: A replenishment carrier injection system is provided for adding carrier particles to a developer housing in a two-component developer toner imaging machine.

Abstract: A developer conveying apparatus includes a first developer storing portion, a second developer storing portion, and a conveying pipe that connects the first and second developer storing portions. The conveying pipe includes a tubular main body and a conveying member rotatably provided in the main body. A groove is formed on a surface of the conveying member, and the groove has a depth less than or equal to 5 ?m.

Abstract: An objective is to provide an image forming method and an image forming apparatus exhibiting neither failure in lack of line image nor image defect in halftone images, together with extremely high image quality and longer lifetime. Disclosed is an image forming method possessing the steps of evenly charging an organic photoreceptor; conducting a light exposure process; conducting a developing process to visualize the electrostatic latent image formed on the organic photoreceptor to form a toner image; transferring the toner image into a transfer medium; and conducting a cleaning process to remove a residual toner from the organic photoreceptor, the method further comprising the step of replenishing a developing device with a developer comprising toner and carrier, wherein the organic photoreceptor comprises a surface protective layer containing a filler, and the carrier is mixed with the toner, after attaching a lubricant onto a carrier particle in advance.

Abstract: A material supplying container and an image forming apparatus are provided. The material supplying container includes two or more containers each of which contains a material; supply openings respectively formed in and corresponding to the containers; and seal members that respectively close the supply openings, wherein the supply openings can be opened by simultaneously operating the seal members.

Abstract: A developing agent storage device for storing a refill developing agent includes toner particles, carrier particles, an inner layer of the developing agent storage device. The toner particles and carrier particles compose the refill developing agent. The inner layer is provided as a wall contacting the refill developing agent. An electrostatic chargeability level of the toner particles, the carrier particles, and the inner layer is set in an order of toner, inner layer, and carrier from any one of a negative charge side and a positive charge side.

Abstract: A developing cartridge includes an image receptor which spreads developer on a printing medium, a developer storing part which stores a plurality of developers having a different material property and a different supplying order according to the concerned material property, and a developer feeding unit which sequentially transfers each of the developers to the image receptor according to the supplying order.

Abstract: A developing device that efficiently adjusts the amount of charge on the developing agent without being affected by external conditions, and that continuously supplies a developing agent with the appropriate toner concentration and amount of charge. An ionized air flow adjusts the amount of charge on the developing agent discharged from the developing unit to improve the dispersability of the replenished toner without applying unnecessary stress. The developing agent is raised upwards by a screw, downwards by an agitation member, and then gathered by a screw in a circulating flow. Consequently, the developing agent is uniformly mixed within the developing agent agitation unit. This circulating flow of the developing agent increases the probability of contact and reduces damage to the developing agent. When the ionized air flow reduces the amount of charge before agitation, the toner can be uniformly charged to the appropriate value.

Abstract: A developer apparatus, includes: a container which houses toner; a toner carrier roller which is provided, on a surface thereof, with a plurality of convex sections which are regularly arranged and a concave section which surrounds the convex sections, is shaped approximately like a cylinder, and rotates while carrying a toner layer of charged toner supplied from the container on the surface thereof; and a restriction member which abuts on the toner layer on the surface of the toner carrier roller to restrict a thickness of the toner layer, and restricts the toner layer carried by the convex sections within the surface of the toner carrier roller to one layer or less.

Abstract: A replenishment and image mottle reduction system for adding carrier particles to a developer housing in a two-component developer toner imaging machine. The replenishment system includes (i) a carrier-only hopper for receiving and containing a first quantity of carrier particles; (ii) metering valves connected to a discharge end of the carrier-only hopper; (iii) a pneumatic plenum connected to the metering valves; (v) an air blower connected to the carrier-only hopper and to the pneumatic plenum for pressurizing the carrier-only hopper and for pneumatically conveying a metered quantity of carrier particles in an air stream from the pneumatic plenum; and (vi) a carrier separator assembly connected to the pneumatic plenum, located above each developer housing and including a carrier current collector, for separating fresh carrier from the air stream, and for allowing the carrier separated as such to drop by gravity into the developer housing.

Abstract: An image forming apparatus includes: an image holder; a developing device that develops a latent image formed on the image holder with developing material; a developing material cartridge that has a supply developing material container to contain developing material; and a developing material conveyance unit, having a connection portion connected to the developing device, that conveys the developing material from the supply developing material container to the developing device. The developing material cartridge is provided in a direction approximately orthogonal to the developing device. At least a part of the connection portion is provided within a heightwise directional width of the developing material cartridge.

Abstract: According to an embodiment, a developing device, comprising: a developing unit configured to store an initial two-component developer including an initial toner containing silica externally added and a carrier and to form a toner image on an image bearing member with the two-component developer; a discharging section configured to discharge a part of the initial developer from the developing unit; and a developer supplying unit configured to supply a supply developer including a supply toner containing silica externally added and the carrier to the developing unit, the amount of silica added to the supply toner being smaller than the amount of silica added to the initial toner.

Abstract: A system and method for producing toner associated with a selectable gloss level is provided. The method includes holding a first toner formed of particles, associated with a relatively low gloss level, and having two particle properties, each having a first and second characteristic, respectively, and holding a second toner formed of particles, associated with a relatively high gloss level, and having the two particle properties, each having a third and fourth characteristic, respectively. The first and third and the second and fourth characteristics are substantially the same. The first and second toners are transported and a ratio of their respective volumes is determined so that when blended a third toner is produced which is associated with a selected gloss level that is in-between the low and high gloss levels. The transporting is controlled in accordance with the determined ratio.

Abstract: A developing-agent container contains a developing agent to be supplied to a developing unit. The developing agent contains toner and carrier. The developing-agent container is filled with the developing agent with the toner and the carrier evenly distributed in a highly air-containing state. After filling the developing-agent container with the developing agent, an external force is applied on at least one of the toner and the carrier in the toner container so that a difference in forces per unit volume of the toner and the carrier due to gravity becomes small.

Abstract: An image forming apparatus including an image bearing member and a developing device configured to develop an electrostatic image on the image bearing member with a toner to form a toner image thereon and including a developing unit configured to develop the electrostatic image, and a toner cartridge configured to supply the toner to the developing unit through at least one opening, wherein the developing device circulates the toner between the toner cartridge and the developing unit through the at least one opening, and wherein the internal temperature of the hopper is higher than that of the cartridge and the ratio of a charge quantity distribution parameter of the toner under a condition of 45° C. and 54% RH to that under a condition of 25° C. and 54% RH is greater than 0.9 and less than 1.5.

Abstract: An agent transport unit for transporting an agent from a first container to a second container includes a transport route and a pump. The transport route connects the first container and second container, and includes at least one of a first route, a second route, and a third route. The first route extends in a substantially horizontal direction, the second route extends in a substantially vertical direction, and the third route extends in a substantially inclined direction with a repose angle equal to or less than that of the agent. The pump supplies a gas flow into the transport route to transport the agent in the transport route.

Abstract: A toner supply device includes: a toner supply assembly having a toner bottle for holding toner; and a toner supply assembly mounting mechanism having the toner bottle mounted, for feeding toner supplied from the toner bottle to a developing unit. In this toner supply device, toner supplied from the toner supply assembly is fed to the developing unit after it being agitated. The toner supply assembly mounting mechanism includes: guide rails for guiding the toner supply assembly when it is mounted; and a stopper for positioning and holding the toner supply assembly. The toner supply assembly has an abutment surface which is guided by the guide rails and positioned and held by the stopper.

Abstract: A compact development apparatus using a two-component developer and an image forming apparatus wherein carrier deterioration is prevented to ensure formation of a high-quality image for a long time. The development apparatus uses the developer made up of a mixture of toner, carrier, and opposite polarity particles to be charged oppositely to the toner wherein the opposite polarity particles contain the particles having a relative dielectric constant of 6.7 or more.