Abstract: An image forming apparatus includes an image bearing member, a replenishment unit, an agitation member, a drive source, a control unit, a memory unit, and a remaining amount detection unit. The control unit performs (1) a first operation to drive the drive source for a first time in a case where it is judged based on the output value of the remaining amount detection unit that the toner has increased, and (2) a second operation to drive the drive source for a second time that is shorter than the first time in a case where it is judged based on the output value of the remaining amount detection unit that the toner has not increased.

Abstract: An image forming apparatus detects a first current value and a second current value of currents flowing between an image bearing member and a developer carrying member. When a difference between the detected first current value and the detected second current value exceeds a threshold in a state in which the image bearing member and the developer carrying member are rotated and a first developing voltage is applied to the developer carrying member, a controller controls AC voltage applied to the developer carrying member.

Abstract: An image forming apparatus includes a regulating member that regulates a developing agent that a developing agent carrying member carries in order to develop an electrostatic image, and a regulatory bias application portion that applies a regulatory bias to the regulating member, wherein the developing agent includes a toner containing a toner particle, inorganic silicon fine particles present on the surface of the toner particle, and a metal soap, wherein the amount of water-washing migration of the inorganic silicon fine particles is 0.20 mass % or less, wherein a peripheral speed ratio, which is a ratio of a peripheral speed of the developing agent carrying member to a peripheral speed of an image bearing member, has a range of 120% to 300%, and a dark portion potential Vd on the surface of the image bearing member and a regulatory bias Vb satisfy the relationship of Vd<Vb.

Abstract: A method of coating a slip ring for use with a surgical instrument is disclosed. The method includes the steps of providing a slip ring including a plurality of conductive elements, and depositing a material less conductive than the conductive elements onto the conductive elements of the slip ring.

Abstract: Provided is an electrophotographic member which can suppress adhesion of the toner component and fogging even in the case of printing a large number of sheets. The electrophotographic member includes an electroconductive support and an elastic layer and has convex portions composed of the elastic layer on a surface of the electrophotographic member and a filled portion containing a resin at a valley portion between the convex portions, the filled portion has a height lower than heights of the convex portions, and the surface of the electrophotographic member has a specific Martens hardness.

Abstract: An image forming apparatus includes an image bearing member, a charging roller, a toner image forming portion, a voltage source, a detecting member, a controller, and a test executing portion configured to execute an operation in a test mode in which in a period in advance of the image forming period, a plurality of test AC voltages having a test peak-to-peak voltage with different frequencies are successively applied to the charging roller and alternating currents are detected by the detecting member. The test executing portion sets a predetermined peak-to-peak voltage on the basis of a specific frequency which is a maximum frequency at which a relationship between the frequencies and the alternating currents acquired in the operation in the test mode maintains linearity.

Abstract: A drum cartridge includes: a drum frame to which a developing cartridge including a storage medium having an electrical contact surface is detachably attachable; a photosensitive drum; a transfer roller; and a conveying roller. The drum is rotatable about a first axis extending in a first direction and positioned at one end portion of the frame in a second direction. The transfer roller is rotatable about a second axis extending in the first direction and in contact with the drum. The conveying roller is rotatable about a third axis extending in the first direction and separated from the transfer roller in the second direction. A first opening of the frame is positioned between the transfer roller and the conveying roller in the second direction. The electrical contact surface is exposed to an outside through the first opening in a case where the developing cartridge is attached to the frame.

Abstract: A developing blade has a protrusion that protrudes toward a developing roller in an opposing portion facing the developing roller. The potential difference between a supply bias and a developing bias is denoted by ?(V), a contact pressure of the developing blade with respect to the developing roller is denoted by X (gf/cm), a height of the protrusion from the opposing surface that faces the developing roller at a position further toward a tip side than the protrusion is denoted by H (mm), and a length of the opposing surface in the rotation direction of the developing roller is denoted by L (mm). When viewing a cross-section perpendicular to the rotation axis of the developing roller, 0.05?H?0.1, 0.15?L?1.0, and 15?X?60 are established, and at least ???5*X?125 is satisfied.

Abstract: An image forming apparatus includes a control portion configured to perform a cleaning operation including: a first step of causing a developer, which has a reversed polarity and is attracted to a surface of a charging roller, to have a normal polarity under a state in which the developer bearing member is separated from the image bearing member with the contact/separation unit; and a second step of collecting the developer, which has the normal polarity and is attracted to the surface of the image bearing member, to the developer bearing member, by rotating the image bearing member and the developer bearing member under a state in which the developer bearing member is brought into contact with the image bearing member with the contact/separation unit after performing the first step.

Abstract: Provided is a photosensitive dry film capable of forming a solder resist layer that has an excellent filling property of underfill and that exhibits an excellent adhesion with a mold material. The photosensitive dry film according to the present invention is a photosensitive dry film including a supporting film and a photosensitive resin layer provided on one side of the supporting film, wherein the arithmetic average surface roughness Ra of the side of the supporting film on which the photosensitive resin layer is provided is 50 to 390 nm.

Abstract: A dielectric material is provided. The dielectric material includes at least one layer of a substantially continuous phase material. The material is selected from the group consisting of an organic, organometallic, or combination thereof in which the substantially continuous phase material has delocalized electrons.

Abstract: A toner conveyance roller for an image forming apparatus including a toner image forming mechanism including a developing roller and the toner conveyance roller which is arranged opposite to the developing roller and used for supplying and scraping toner, wherein the toner conveyance roller has a roller part and a shaft part, the roller part includes a substantially cylindrical elastic layer composed of an elastic foaming body on a surface of the roller part, and a density of the elastic layer is higher in a longitudinal center part of the roller part than in both longitudinal end parts thereof, and a method for manufacturing the toner conveyance roller including a step of heat-pressing the crown-shaped elastic foaming body, and thereby, forming the elastic layer.

Abstract: An image forming apparatus has a body frame and a slide frame. The slide frame is configured to be pulled out from the body frame along a sliding direction. A plurality of image forming cartridges is detachably mounted on the slide frame. A plurality of electrode members is mounted on the slide frame and aligned along the sliding direction so as to correspond to the image forming cartridges. A body-side contact portion of each of the electrode members is electrically connected to the body frame. A cartridge-side contact portion of the electrode member is electrically connected to the image forming cartridge. The image forming cartridge is connected to the body via the corresponding electrode member when the slide frame mounting the image forming cartridges is inserted to the body frame.

Abstract: An image forming apparatus includes a developing apparatus having a container for storing a developer, a developer carrier in which a surface that carries the developer is configured so that a plurality of dielectric portions is interspersed on a surface formed of a conductor portion, and a regulating member that regulates a layer thickness of the developer that is carried on the developer carrier. In addition, a voltage applying unit applies voltages to the developer carrier and the regulating member.

Abstract: Provided is a member for electrophotography that can achieve both an improvement in toner-conveying force under high temperature and high humidity, and excellent charge-providing performance for a toner, at high levels. The member for electrophotography includes a substrate, an electro-conductive elastic layer on the substrate, and a plurality of electrically insulating domains formed in a partial region on the electro-conductive elastic layer. The electro-conductive elastic layer has a Martens hardness of 0.10 N/mm2 or more and 3.00 N/mm2 or less. In the surface of the member for electrophotography, the exposure ratio of the electro-conductive elastic layer per the area of a square 300 ?m on a side is 50% to 90%, and the average of the areas of the portions of the respective plurality of electrically insulating domains to be brought into contact with the electro-conductive elastic layer is 300 ?m2 or more and 10,000 ?m2 or less.

Abstract: Provided are charge-controlled polyurethane foam by which the influence of electrification by friction between toner on the surface layer of a toner-conveying roller and a developing roller can be sufficiently prevented and by which a good image can be stably obtained with a low cost, and a toner-conveying roller using the same. The charge-controlled polyurethane foam is the one wherein the surface layer of the polyurethane foam is impregnated with a charge control agent which is on the negative side or on the positive side in the triboelectric series with respect to substrate polyurethane foam. The toner-conveying roller is the one which supports the charge-controlled polyurethane foam on the periphery of the axis of the roller.

Abstract: A developing device includes a development housing, a developer carrier, a toner carrier, a bias applying unit, a leakage detecting unit, a bias control unit and a leakage detection control unit. The developer carrier carries a developer layer. The toner carrier receives the toner from the developer layer and supplies the toner to an image carrier. The bias applying unit includes one transformer and applies direct-current voltages and alternating-current voltages to the developer carrier and the toner carrier. The leakage detecting unit detects leakage occurring between the image carrier and the toner carrier or between the toner carrier and the developer carrier. The leakage detection control unit detects a value of an inter-peak voltage, at which the leakage occurs, by applying the same direct-current voltage to the toner carrier and the developer carrier and changing the inter-peak voltages of the alternating-current voltages.

Abstract: In a developing assembly, the surface of a developer bearing member on which a developer is borne is provided with a first dielectric portion and a second dielectric portion. A regulating portion that regulates the layer thickness of the developer borne on the developer bearing member, the first dielectric portion, and the second dielectric portion each have a charge polarity opposite to the charge polarity of the developer. In a triboelectric series, one of the first dielectric portion and the second dielectric portion is positioned between the developer and the other dielectric portion, and the other dielectric portion is positioned between the one of the dielectric portions and the regulating portion.

Abstract: A developing device includes a developer bearer disposed facing a latent image bearer in a development range, and an alternating voltage application unit to apply alternating voltage to the developer bearer to generate an alternating electrical field in the development range to cause toner to move from the developer bearer to the latent image bearer while reciprocating therebetween. The alternating voltage has a frequency within a range from 20 kHz to 60 kHz and a peak-to-peak voltage equal to or greater than 300 V.

Abstract: An image forming unit includes a developer bearing body that bears a developer, and a supplying member provided so as to face the developer bearing body. The supplying member rotates to thereby collect the developer from the developer bearing body and supply the developer to the developer bearing body. The image forming unit further includes a developer storage portion that stores the developer to be supplied to the supplying member, and a charge providing member that charges the developer held on the supplying member. In a rotating direction of the supplying member, the charge providing member is disposed on a downstream side of an opposing portion between the developer bearing body and the supplying member and on an upstream side of a region where the developer storage portion supplies the developer to the supplying member.

Abstract: In an image forming apparatus having a photosensitive drum that carries a toner image, a developing roller that is provided to be capable of rotating while carrying toner, and that supplies the toner to the photosensitive drum in order to develop a latent image, and voltage applying device for applying a voltage to the developing roller, the developing roller includes a conductive base layer and a surface layer covering the base layer, and a surface charge density of the developing roller is equal to or smaller than a surface charge density of the toner.

Abstract: A developing device which includes a developing roller which supplies a toner to a photoreceptor and a supply roller which performs supply of a toner to the developing roller and peeling of a toner from the developing roller, and applies a bias voltage to the developing roller so as to develop an electrostatic latent image formed on the photoreceptor with a toner. The developing device includes a first current measuring portion which measures a value of a current flowing in the developing roller, a second current measuring portion which measures a value of a current flowing in the supply roller, and a control portion which calculates a toner charging amount on the developing roller and a toner peeled amount by the supply roller based on measured results by the first current measuring portion and the second current measuring portion.

Abstract: A developing device including a toner holding member that faces but is not in contact with an image carrier carrying a latent image and that rotates while holding a nonmagnetic toner, a charging member that charges the toner, and a developing electric field forming unit that forms a developing electric field at least including a direct current component to cause the charged toner to fly and adhere to the latent image to develop the latent image. When the developing electric field is applied such that the toner is caused to fly toward the image carrier by the direct current component of the developing electric field, maintaining a non-electrostatic adhesion of the toner to the toner holding member to be about 2 nN or more under a low-temperature low-humidity environment of a temperature of 10° C. and a relative humidity of 15%. The toner holding member's surface has a specific surface roughness specified by a specific oil retention volume.

Abstract: An image forming apparatus includes a toner carrying roller for carrying a toner, an image carrying member, contacting the toner on the toner carrying roller, on which a toner image is to be formed with the toner, and an electrode portion provided at an opposing position in which the electrode portion opposes the toner carrying roller via the image carrying member interposed therebetween. The toner image is formed on the image carrying member by changing a value of a voltage, on the basis of image information, applied to the electrode portion, and the toner carried on the toner carrying roller and the image carrying member contact each other in a toner contact area. The toner is moved between the toner carrying roller and the image carrying member in a toner movement area by changing the value of the voltage applied to the electrode portion, and the toner movement area is present downstream of the toner contact area with respect to a movement direction of the image carrying member.

Abstract: An image forming apparatus having; a latent image support member; a latent image forming unit for forming an electrostatic latent image on the latent image support member; a developer support member for supplying toner to the latent image support member to develop the electrostatic latent image; a voltage applying device for applying a developing bias, which is a superimposed voltage of a DC voltage and an AC voltage, to the developer support member; a first selecting device for selecting a screen ruling; and a second selecting device for selecting a frequency of the AC voltage. The second selecting device selects a first frequency when the first selecting device selects a first screen ruling, and selects a second frequency lower than the first frequency when the first selecting device selects a second screen ruling higher than the first screen ruling.

Abstract: A developing device includes a developer bearing member that bears a developer on its surface to supply the developer to an image bearing member having a first dielectric portion and a second dielectric portion in its surface, a regulating member that regulates a thickness of a layer of the developer carried by the developer bearing member, and a flexible sheet-like charging auxiliary member disposed so as to be in contact with the developer bearing member at a position downstream of a contact portion between the developer bearing member and the image bearing member and upstream of a contact portion between the developer bearing member and the regulating member in a rotational direction of the developer bearing member, where the charging auxiliary member charges the developer carried by the developer bearing member. In a triboelectric series, the charging auxiliary member is positioned between the first and second dielectric portions.

Abstract: In a developing assembly, the surface of a developer bearing member on which a developer is borne is provided with a first dielectric portion and a second dielectric portion. A regulating portion that regulates the layer thickness of the developer borne on the developer bearing member, the first dielectric portion, and the second dielectric portion each have a charge polarity opposite to the charge polarity of the developer. In a triboelectric series, one of the first dielectric portion and the second dielectric portion is positioned between the developer and the other dielectric portion, and the other dielectric portion is positioned between the one of the dielectric portions and the regulating portion.

Abstract: An image forming apparatus includes a latent image carrier; a latent image writer to write a latent image on the latent image carrier; a developing unit including a toner carrier having first and second electrodes insulated via an insulator member and a voltage applying unit to apply voltages to the first and second electrodes having a potential difference to generate first electric fields to cause the toner to hop from the toner carrier to the latent image carrier to develop a toner image; and a transfer unit to transfer the developed toner image to a transferring member. When alternating voltages having a same phase and same amplitude are applied to the first and second electrodes to form second electric fields between the latent image carrier and the toner carrier, the toner is discharged from the toner carrier to the latent image carrier in a toner discharge mode.

Abstract: An image forming apparatus includes a latent image carrier to carry a latent image, a developing device having a toner carrier with first and second electrodes to develop the latent image by transferring the toner to a developing region between the toner carrier and the latent image carrier while causing the toner to hop between the first and second electrodes and attaching the hopping toner to the latent image, a pulsed power supply to output a first periodic pulse voltage having a mean potential the same as a normal toner charge and a second periodic pulse voltage, a smoothing circuit to make the first periodic pulse voltage smooth to generate a direct voltage, and a toner layer thickness regulator member to regulate, on receiving the direct voltage, a thickness of the toner layer in a region between a toner supply position at which toner is supplied and the developing region.

Abstract: A developing device includes a developer bearer disposed facing a latent image bearer in a development range, and an alternating voltage application unit to apply alternating voltage to the developer bearer to generate an alternating electrical field in the development range to cause toner to move from the developer bearer to the latent image bearer while reciprocating therebetween. The alternating voltage has a frequency within a range from 20 kHz to 60 kHz and a peak-to-peak voltage equal to or greater than 300 V.

Abstract: An image forming apparatus, wherein the packing density at a closest point where the first peripheral surface and the second peripheral surface are the closest to each other is within a range from 0.3 to 0.4; wherein a maximum magnetic flux density of a principal magnetic pole for generating the magnetic field for development is located in an upstream side from the closest point with respect to the specified direction and at a point where the packing density is equal to or greater than 0.2; and wherein a magnetic flux density of the principal magnetic pole at a point where the packing density is 0.2 in a downstream side from the closest point with respect to the specified direction is equal to or less than ½ of a magnetic flux density of the principal magnetic pole at a point where the packing density is 0.2 in the upstream side.

Abstract: Printers are provided in which a charge pattern is formed with a second area having a surface potential that is at least 30 percent less than a surface potential of an adjacent first area that creates an inter-area field between the first area and second area that extends into a portion of the first area that is proximate to the second area. A development station applies a first development field and a first toner is partially developed in the first area based upon the influence of the inter-area and first development fields. The charge pattern and first toner are further developed with a different second toner. The surface charge, the first toner and second toner have the same polarity.

Abstract: Methods are provided in which a charge pattern is formed with a second area having a surface potential that is at least 30 percent lower than a surface potential of an adjacent first area that creates an inter-area field between the first area and second area that extends into a portion of the first area. A development station applies a first development field and a first toner is partially developed in the first area based upon the influence of the inter-area and first development fields. The charge pattern and first toner are further developed with a different second toner. The surface charge has a different polarity than a polarity of the first toner and second toner.

Abstract: Printers are provided in which a charge pattern is formed with a first area having a surface potential that is at least 30 percent less than a surface potential of an adjacent second area that creates an inter-area field between the first area and second area that extends into a portion of the first area that is proximate to the second area. A development station applies a first development field and a first toner is partially developed in the first area based upon the influence of the inter-area and first development fields. The charge pattern and first toner are further developed with a different second toner. The surface charge, the first toner and second toner have the same polarity.

Abstract: The present invention provides a conductive member in which it is possible to control a variation in resistance due to physical stress from a contact member, and an uneven density in a halftone image can be prevented. The conductive member is a development roller which includes a conductive shaft core, a conductive elastic layer, and a conductive surface layer. The conductive elastic layer contains silicone rubber and a basic carbon black dispersed in the silicone rubber. The surface layer contains a urethane resin having a carboxyl group in its molecule and an acidic carbon black dispersed in the urethane resin.

Abstract: Printing methods are provided. A surface charge is provided on the primary imaging member and the surface charge is partially discharged in areas in which a first toner is to develop. The charge pattern is formed with a first area having a surface potential that is at least 30 percent less than a surface potential of an adjacent second area that creates an inter-area field between the first area and second area that extends into a portion of the first area that is proximate to the second area. A first development field is applied and a first toner is partially developed in the first area based upon the influence of the inter-area and first development fields. The charge pattern and the first toner are further developed with a different second toner. The surface charge on the primary imaging member, first toner and second toner have the same polarity.

Abstract: An image forming apparatus for forming a toner image on a print medium with a developer composed of toner and carriers, wherein when the first distance is longer than the second distance, an average gap between the first peripheral surface and a member that faces to the first peripheral surface in an area with a length of the first distance extending upstream from the closest point with respect to the specified direction is smaller than an average gap between the first peripheral surface and a member that faces to the first peripheral surface in an area with a length of the first distance extending downstream from the closest point with respect to the specified direction.

Abstract: A developing device includes a container, a toner holding member, a developing electric field forming unit, a layer forming unit, an electrode member, and a low-frequency electric field forming unit. The container accommodates toner. The toner holding member holds toner and transports the toner to a developing region where the toner holding member and the latent image holding member face. The developing electric field forming unit forms a developing electric field for developing a latent image held on a latent image holding member. The layer forming unit forms a toner layer on the toner holding member prior to the developing region. The electrode member faces the toner holding member. The low-frequency electric field forming unit forms a low-frequency electric field acting on residual toner between the electrode member and the toner holding member, and forms stripe-shaped projections in accordance with a period of the low-frequency electric field.

Abstract: A development method is used for a developing device including a toner holding member that faces but is not in contact with an image carrier carrying a latent image and that rotates while holding a nonmagnetic toner, a charging member that charges the toner, and a developing electric field forming unit that forms a developing electric field at least including a direct current component to cause the charged toner to fly and adhere to the latent image to develop the latent image. The method includes, when the developing electric field is applied such that the toner is caused to fly toward the image carrier by the direct current component of the developing electric field alone, maintaining a non-electrostatic adhesion of the toner to the toner holding member to be about 2 nN or more under a low-temperature low-humidity environment of a temperature of 10° C. and a relative humidity of 15%.

Abstract: A developer supply device is provided, which includes a developer retrieving member disposed to face a developer holding surface of a developer holding member across a predetermined distance in a position downstream relative to a developer supply position where the developer holding member faces an intended device to be supplied with development agent in a direction perpendicular to a main scanning direction parallel to an axial direction of the developer holding member. The developer retrieving member is driven to rotate around an axis parallel to the main scanning direction and configured to retrieve the development agent from the developer holding surface under a retrieving electric field that is generated when a retrieving voltage is applied between the developer retrieving member and the developer holding member.

Abstract: An image forming apparatus includes a toner carrying member for carrying a toner; an image carrying member, contacting the toner on the toner carrying member, on which a toner image is to be formed with the toner; and an electrode portion provided at an opposing position in which the electrode portion opposes the toner carrying member via the image carrying member interposed therebetween. The toner image is formed on the image carrying member by changing a value of a voltage, on the basis of image information, applied to the electrode portion. The toner carried on the toner carrying member and the image carrying member contact each other in a toner contact area. The toner is moved between the toner carrying member and the image carrying member in a toner movement area by changing the value of the voltage applied to the electrode portion. The toner movement area is present downstream of the toner contact area with respect to a movement direction of the image carrying member.

Abstract: An image forming apparatus includes: an image carrier; a toner image forming unit that forms a toner image on the image carrier; a transfer unit that transfers the toner image on the image carrier to a transfer target having ridges and valleys on a surface thereof; an adjusting unit that adjusts a ratio of A/B, where A is a transfer ratio [%] from the image carrier to a valley portion of the transfer target while B is a transfer ratio [%] from the image carrier to a ridge portion of the transfer target, based on an adjustment input by a user; and a control unit that controls a transfer condition of the transfer unit based on the ratio of A/B adjusted by the adjusting unit.

Abstract: A developing roller configured to develop an electrostatic latent image on a photosensitive drum, a supply roller configured to supply developer to the developing roller are provided, and the surface of the developing roller moves in the same direction as the surface of the photosensitive drum and at a speed higher than the photosensitive drum at a nip portion between the photosensitive drum and the developing roller, the surface of the supply roller moves in the same direction as the surface of the developing roller and at a speed higher than the developing roller at a nip portion between the developing roller and the supply roller.

Abstract: A power supply apparatus outputs a developing voltage in which a pulse wave shape at a time of positive amplitude is different from a pulse wave shape at a time of negative amplitude. Voltages are supplied from two switching regulators respectively to a bridge circuit for driving a transformer. Here, an absolute value of a difference between a drive frequency of a first switching regulator and a drive frequency of a second switching regulator is configured to be not less than an invisible frequency at which a banding cannot be recognized by humans.

Abstract: A developing device including a containing unit configured to be arranged below a supply member and contain a developer and a developer bearing member configured to bear the developer and develop an electrostatic latent image, further includes a supply member which is configured to supply the developer to the developer bearing member, to be arranged to form a nip portion between the supply member and the developer bearing member, and to rotate in a direction in which its surface moves from an upper end to a lower end of the nip portion, and a conveyance member which is configured to convey the developer contained in the containing unit onto the supply member.

Abstract: Methods are provided in which a charge pattern is formed with a second area having a surface potential that is at least 30 percent lower than a surface potential of an adjacent first area that creates an inter-area field between the first area and second area that extends into a portion of the first area. A development station applies a first development field and a first toner is partially developed in the first area based upon the influence of the inter-area and first development fields. The charge pattern and first toner are further developed with a different second toner. The surface charge has a different polarity than a polarity of the first toner and second toner.

Abstract: Printing methods are provided. A surface charge is provided on the primary imaging member and the surface charge is partially discharged in areas in which a first toner is to develop. The charge pattern is formed with a first area having a surface potential that is at least 30 percent less than a surface potential of an adjacent second area that creates an inter-area field between the first area and second area that extends into a portion of the first area that is proximate to the second area. A first development field is applied and a first toner is partially developed in the first area based upon the influence of the inter-area and first development fields. The charge pattern and the first toner are further developed with a different second toner. The surface charge on the primary imaging member, first toner and second toner have the same polarity.

Abstract: Printers are provided in which a charge pattern is formed with a second area having a surface potential that is at least 30 percent less than a surface potential of an adjacent first area that creates an inter-area field between the first area and second area that extends into a portion of the first area that is proximate to the second area. A development station applies a first development field and a first toner is partially developed in the first area based upon the influence of the inter-area and first development fields. The charge pattern and first toner are further developed with a different second toner. The surface charge, the first toner and second toner have the same polarity.

Abstract: Printers are provided in which a charge pattern is formed with a first area having a surface potential that is at least 30 percent less than a surface potential of an adjacent second area that creates an inter-area field between the first area and second area that extends into a portion of the first area that is proximate to the second area. A development station applies a first development field and a first toner is partially developed in the first area based upon the influence of the inter-area and first development fields. The charge pattern and first toner are further developed with a different second toner. The surface charge, the first toner and second toner have the same polarity.

Abstract: An image forming apparatus include an image bearing member, a developing container receiving a developer, a developer carrying member for carrying and conveying the developer, a developer feed member for supplying the developer to the developer carrying member, a detection device for detecting an amount of developer in the developing container by detecting an electrostatic capacitance between the developer carrying member and the developer feed member, and a control device for changing a rotational speed of the developer feed member into a plurality of speeds corresponding to the plurality of image forming speeds. The control unit controls the rotational speed of the developer feed member prior to the execution of a detection operation of the detection device so as to be faster than the slowest speed of said plurality of speeds.