Abstract: A method for developing an electrostatic latent image including the step of developing an electrostatic latent image with a two component developer including a particulate carrier and a negatively charged toner and held on the surface of a developing roller to form a toner image, wherein the developing roller surface includes a material including one or more carbon atoms and one or more nitrogen atoms, and wherein a ratio of the number of carbon atoms to the number of nitrogen atoms is not greater than 100/1.

Abstract: A development roller has a core shaft and an external composite layer provided around the core shaft, the external composite layer including an elastic layer and a surface layer which are successively overlaid on the core shaft in that order, the development roller having a volume resistivity of 1.5×104 &OHgr;·cm or less and an electrostatic capacity of 1.5×10−4 F/m2 or more. A developer unit is provided with the above-mentioned development roller which is disposed so as to have a toner deposited on an image portion formed on a surface of a photoconductor, a toner supply roller which is disposed opposite to the development roller and is capable of forming therearound a magnetic brush of the toner and a carrier, and brings the magnetic brush into contact with the development roller to supply the toner to the development roller, and a doctor blade disposed in contact with the surface of the toner supply roller to regulate the thickness of a layer of the toner.

Abstract: In a method for forming a color image by using a contact type nonmagnetic one-component developing device, a flat sheet-like blade made of a metal flexible member and having a distal end thereof chamfered is used inside the developing device in combination with a toner having a glass transition point of 55 to 70° C. and a weight average particle diameter of 6.0 to 10.0 &mgr;m, and containing up to 20 number % of particles having particle diameters of 5 &mgr;m or below, as a developer. The developing device is simple in construction, can provide high image quality and can, moreover, provide a highly reliable image formation method.

Abstract: A developing roller (10) comprising an elastic layer (12) wound round a conductive shaft (11) and one or more resin layers (13) laminated on the elastic layer. The elastic layer (12) has a JIS A hardness of not greater than 50 degrees. At least the outermost layer of the one or more resin layers (13) contains fine particles and the surface roughness (Rz) of the outermost layer is regulated to be within the range of 3 to 15 &mgr;m. A resin composition containing an —NHCO— bound or a resin composition containing —ROCO2— and —SiOSi— repeating units and an —NHCO— bond can be used for the outermost layer.

Abstract: There are disclosed a toner carrier (1) having at least 0.

Abstract: A copying machine consists of a photosensitive drum, a charging section, an exposure section, a developing section, a corona charging section, a cleaning section, a current removing section, and a fixing roller. In the developing section for carrying out a development by bringing a developing roller into contact with or bringing the developing roller close to a photosensitive layer, the following expression (1) has been established: 1≦(td/∈d)/(tp/∈p)≦8  (1) where ∈d and td (&mgr;m) represent a dielectric constant and a thickness of the dielectric layer respectively, and ∈p and tp (&mgr;m) represent a dielectric constant and a thickness of the photosensitive layer respectively.

Abstract: A developing roller having a superior setting ability and having a uniform and high conductivity is provided by improving dispersion and stability of carbon black mixed in a solution of a coating resin, and then forming a resin layer that has a low modulus of elasticity and a high conductivity when coated. The developing roller comprises a core shaft, an elastic body layer formed around the core shaft and made of rubber as a main ingredient, and a resin layer coated at least on an outer surface of the elastic body layer. The resin layer contains carbon black having a DBP absorption amount of 80 to 110 ml/100 g, a ratio of a DBP absorption amount to a nitrogen specific surface area being not more than 0.012 ml/m2, and a ratio of a volatile component to a nitrogen specific surface area being not more than 2.0×10−4 g/m2.

Abstract: An object of the invention is to facilitate the design of a developing apparatus by making it easier to set the optimal developing conditions in upgrading an image quality when forming an image with a dielectric developing roller. Developing conditions are set so as to satisfy Cc≧&rgr;t·dt·k/Vv, wherein Vv=−(Vbp+Vpr)−Vco+Vt·k; Cc=1/{1/Cp+2/Ct+rr/k+1/(Cr3·k)}; k=vr/vp; rr=&rgr;r·d2; Cp=&egr;p/dp; Ct=2·&egr;t/dt; Cr1=&egr;1/d1; Cr2=&egr;2/d2; C1−1/{1/Cp+2/Ct+1/(Cr1·k)}; C2=k·Cr2; Ex=(W/vp)/{rr·(C1+C2)}; Cr3=Cr1·{1−C1/(C1+C2)}·exp(−Ex); &rgr;t=(qpm+qr)·m/dt; Vco=−qpm·m/Cr1; Vpr=−qr·m·k/Cp; Vt=&rgr;t·dt/Ct.

Abstract: A heat developing method conveying, to make a heating processing on a heater surface, a heat developable image recording material is disclosed in which an image forming layer and a protection layer are formed using a polymer latex as a binder on one side of a support made prepared by subjecting a polyester biaxially drawn and crystallized with orientation to a thermal relaxation processing at a temperature equal to or higher than 130° C. and equal to or lower than 200° C.

Abstract: A developing device according to the present invention comprises an image developing roll 4 having a roll surface treated with sand blast treatment to form a rough surface morphology in which aluminum anodizing is also applied to the surface of the image developing roll 4 where the rough surface morphology is formed. To the image developing roll 4 is applied a development bias consisting of a direct current voltage overlapped with an alternate current voltage. In this arrangement, the image developing roll 4 can perform the functions of conveying developer, charging developer, and preventing of discharge of the developing bias, while the image developing roll 4 can be manufactured from a metallic roll such as aluminum roll at a low cost. Moreover, a gradual scraping of the image developing roll 4 surface by external additives of toner 3 suppresses adhering of toner 3 onto the surface of the image developing roll 4, preventing the occurrence of filming.

Abstract: It is an exemplified object of the present invention to provide a development device, development roller and blade used in the development device, and development roller and image-forming device having the development roller and blade, which can form a high-quality image by a cost-efficient means. To achieve this object, the inventive development roller comprises a shaft, a base material that coats a periphery of the shaft, and is made of a resistance body, and a layered coating provided on a periphery of the base material, where the layered coating includes two or more layers, a coating layer provided inside an outermost coating layer has a higher charging capability to a developing agent than at least the outermost coating layer.

Abstract: An aluminum roll for use in an apparatus in which making particles are advanced toward a latent image to form a developed image. The roll is formed by diamond turning prior to forming an anodization layer and prior to applying a sealant.

Abstract: A roller includes a core and a ceramic coating formed over the core. The roller has a composite runout of less than 20 &mgr;m and a total indicator reading runout of less than 7 &mgr;m. The ceramic coating has a smooth finish and has controlled electric properties. This roller can be used as a donor roller for transporting toner to a photoconductive member so as to achieve high-quality image development.

Abstract: A toner carrier is included in an image forming apparatus wherein the electrical resistance between a shaft of the toner carrier and a surface which covers the shaft is different depending on the polarity of the voltage applied between th shaft and the surface. A resistance characteristic is thereby obtained having a resistance that allows prescribed current to flow from the shaft side to the surface side and which makes current flow from the surface side to the shaft side difficult. This prevents leakage current being received from the surface of the photosensitive drum. The amount of charging up of the toner therefore does not drop and a prescribed amount of charging up can be maintained, which means that fog of the image background surface does not occur. Furthermore, because there is no voltage dependence at the toner carrier surface from the shaft side, stable image density can be achieved, enabling high image quality to be achieved.

Abstract: A developing apparatus has a developer carrying body carrying a developer thereon, and a layer thickness regulating member for regulating the layer thickness of the developer carried on the developer carrying body. The developer carried on the developer carrying body contacting with an image bearing body after the layer thickness thereof has been regulated by the layer thickness regulating member. In the developing apparatus, when the charge amount per 1 g of the developer after the layer thickness has been regulated by the layer thickness regulating member and before the developer contacts with the image bearing body is defined as Q (&mgr;C/g) and the electrical resistance per axial length 1 mm of the developer carrying body is defined as R (&OHgr;/mm), R≧0.9×(−7.83×104|Q|+7.05×106) and R≦1.1×(−7.83×104|Q|+7.05×106) are satisfied.

Abstract: A developer roll sleeve and method for making the same is disclosed. In a preferred embodiment, a core substrate roll is spray coated with a conductive composition comprising a host resin composition and a wear-resistance imparting additive. Preferably, the host resin composition comprises a phenolic thermosetting resin and a conductivity additive such as carbon black, graphite and the like. Further, the wear resistance imparting additive is preferably selected from the group consisting of a polytetrafluoroethylene resin (e.g., Teflon), graphite, ultra-high molecular weight polyethylene having a molecular weight from about 3,000 to about 4,500 grams, molybdenum, molybdenum disulfide, silicone and mixtures thereof. The wear resistance imparting additive is preferably provided in an amount sufficient to obtain a thickness wear rate of less than about 0.00047 percent per printing cycle.

Abstract: A method for developing an electrostatic latent image including the step of developing an electrostatic latent image with a two component developer including a particulate carrier and a negatively charged toner and held on the surface of a developing roller to form a toner image, wherein the developing roller surface includes a material including one or more carbon atoms and one or more nitrogen atoms, and wherein a ratio of the number of carbon atoms to the number of nitrogen atoms is not greater than 100/1.

Abstract: A developing apparatus according to the present invention comprises a developer carrying member for holding a developer and introducing the developer into a developing area opposite to the image carrying member at a required distance; a voltage applying device for applying an AC voltage to the developer carrying member; and a resistor inserted between the developer applying device and the developer carrying member, the AC voltage applied to the developer carrying member from the voltage applying device through the resistor being composed of a rectangular wave, and a time period during which a voltage, which is exerted in the direction in which the developer is fed to the image carrying member, in the AC voltage is less than 50% of a time period during which the AC voltage is exerted.

Abstract: A developer roll sleeve and method for making the same is disclosed. In a preferred embodiment, a core substrate roll is spray coated with a conductive composition including a host resin composition and a wear-resistance imparting additive. Preferably, the host resin composition includes a phenolic thermosetting resin and a conductivity additive such as carbon black, graphite and the like. Further, the wear resistance imparting additive is preferably selected from the group consisting of a polytetrafluoroethylene resin (e.g., Teflon), graphite, ultra-high molecular weight polyethylene having a molecular weight from about 3,000 to about 4,500 grams, molybdenum, molybdenum disulfide, silicone and mixtures thereof. The wear resistance imparting additive is preferably provided in an amount sufficient to obtain a thickness wear rate of less than about 0.00047 percent per printing cycle.

Abstract: A toner cartridge for an electrostatic printer or copier includes an electrophotographic drum, a toner container, a fixed electrode for receiving a developing bias voltage, and a developer roller for supplying the toner to an electrostatic latent image on the electrophotographic drum. A drive hub is press fit into an end of the developer roller. The drive hub has a unitary nonconducting plastic body, with a plug portion for elastically and slidably press-contacting the end of the developer roller, an elongated axle portion with an uninterrupted bearing surface, a shoulder portion for supporting a spring, and a longitudinal passage running through the axle and shoulder portions. A wire is disposed in the passage and makes an electrical connection with the spring and the developer roller.

Abstract: A roller is provided. The roller includes a ceramic body, an aluminum member attached to the ceramic body, and a shaft attached to the aluminum member.

Abstract: A roller is provided. The roller includes a ceramic body, an aluminum member attached to the ceramic body, and a shaft attached to the aluminum member.

Abstract: A low-friction single component development apparatus for developing electrostatic latent images on an image bearing surface is provided. It includes a sump containing a supply of developer material particles; a moveable donor member assembly including a donor member for transporting developer material particles through a development zone; a first combination of AC and DC biases for charging developer material particles in the sump resulting in charged developer material particles having a desired polarity and charge distribution; a second combination of AC and DC biases for providing fringe electric fields for depositing particles of the charged developer material particles onto the donor member; devices for forming a developer material cloud within the development zone for image development; and an electrostatic filtering zone located upstream of the development zone for electrostatically removing wrong-sign charged developer material particles from the donor member.

Abstract: A developing roller and a developing device are provided to enable a satisfactory developing operation. In order to accomplish this object, a roller main body of the developing roller is made of a roller base material containing acrylonitrile-butadiene rubber as a main component, and an adherence preventing coating layer is formed on the outer circumferential surface of the roller main body, thereby preventing the adherence of developer to the roller main body. Particularly, by setting the friction coefficient of the coating layer within a range of 0.5 to 0.95 inclusive and/or the glossiness thereof within a range of 4.5 to 8 inclusive, an occurrence of any of negative ghost, positive ghost and background fogging is prevented or suppressed to a level where no problem is presented in practical use.

Abstract: A developer-carrying member to be installed in an electrophotographic developing device for carrying and conveying a developer along a surface thereof, is formed of a substrate, and an intermediate electroless plating layer and an electroplating layer disposed in this order on the substrate. As a result of the electroless and electro double plating layer structure, the developer-carrying member is provided with a wear-resistant surface which has an appropriate degree of roughness suitable for conveying the developer thereon and is yet free from minute projections and cracks undesirable from the viewpoint of continuous image forming performances.

Abstract: An image forming apparatus including a cylindrical image carrier configured to carry an electrostatic latent image while rotating, and a cylindrical developer carrier configured to bear a developer and supply the developer to the image carrier by contacting the image carrier at a nip while rotating, wherein the surface of the image carrier has a friction coefficient of from about 0.1 to about 0.4. The image carrier may be an endless belt.

Abstract: An object of the present invention is to prevent an electrical breakdown of a toner layer and an occurrence of overcurrent, thereby preventing quality of image from being degraded at the time of development, when development with one-component toner is conducted using a developing roller of low resistance. The resistance value Rd of a developing roller which carries and conveys one-component toner in a manner of coming into contact with a photoconductor which bears an electrostatic latent image, is defined as Rd=.rho.d.multidot.(Dd1/S1), wherein S1 (cm.sup.2) is an area in which the developing roller comes into contact with the static image bearing member via a toner layer, Dd1 (cm) is a layer thickness of a semiconductive layer which composes the developing roller, and .rho.d (.OMEGA..multidot.cm) is a volume resistivity thereof. The range of the resistance Rd is set as 10.sup.4 <Rd<10.sup.5 and the resistance Rt (.OMEGA.) of the toner layer is set as Rt>5.times.10.sup.7.

Abstract: A developer carrying member for carrying a developer is includes a substrate and a resin coat layer which is formed on the surface of the substrate and contains a binder resin and a conductive fine powder. The binder resin is composed of a copolymer having a monomeric unit of a methyl methacrylate monomer (M) and a monomeric unit of a nitrogen-containing vinyl monomer (N). A copolymerization molar ratio of the methyl methacrylate monomer (M) to the nitrogen-containing vinyl monomer (N) in the copolymer fulfills the following condition: M:N=4:1 to 999:1. The binder resin has a weight-average molecular weight (Mw) of from 3,000 to 50,000.

Abstract: A developing apparatus includes a developer container for containing a developer; a developer bearing member for bearing the developer contained in the developer container, the developer bearing member having a surface layer containing substantially spherical particles, wherein a relation between a weight-average particle diameter r (.mu.m) of a toner in the developer and a volume-average particle diameter R (.mu.m) of the spherical particles satisfies an equation 0.5.ltoreq.R/r.ltoreq.1.9.

Abstract: A toner carrier which gives good images (free of fogging in white area, harshness in halftone area, and density variation in black area) even after continuous long runs. The toner carrier includes an electrically conductive elastic layer and a coating layer formed thereon which contains a siloxane-crosslinked acrylic resin obtained from an acrylic copolymer with an alkoxysilyl group by crosslinking and curing.

Abstract: A developing device has a developing container containing a toner therein, and a toner carrying member provided in the opening portion of the developing container and rotatable with the toner carried thereon. The difference between the work function of the surface of the toner carrying member and the work function of the toner is greater than 0.1 and smaller than 1.0.

Abstract: A developing unit of the present invention includes a case which accommodates toner containing pigment, a developing roller, a supply roller having chamfered ends and formed of an elastic member arranged to be pressed against a surface of the developing roller in such a manner as to supply toner to the surface of the developing roller. The side surfaces of the developing roller have a surface roughness of 0.5 .mu.m or smaller in Rmax.

Abstract: A cylinder (2) for a printing machine, particularly a developing cylinder in an electrographic printing machine, having a rigid, elongated shaft body (10) and a rigid hollow body (11) whose exterior forms the covering and the top and bottom surfaces of the cylinder. In order that, during operation under constant conditions, the cylinder can roll properly against another rigid cylinder of the printing machine, flat sides (12,13) of the hollow body (11) which form the top and bottom surfaces of the cylinder, have centrical bore holes that are larger than the diameter of the shaft body (10) in the area of the flat sides. Located in the space between the shaft body and the flat sides of the hollow body is an elastic material (14,15) which joins the flat sides of the hollow body to the shaft body.

Abstract: A developing roller supports a one-component developer on a surface thereof in the form of a thin layer, and is brought in contact with or in proximity to an image forming body in such a state, to supply the developer on a surface of the image forming body, thereby allowing a visible image to be formed on the surface of the image forming body. The developing roller includes: an elastic layer having an ionically conductivity whose surface is imparted with a resin component having a high resistivity. Thus, if R1 is a resistance of the roller in a stationary state and R2 is a resistance of the roller in a rotational state, a relationship of R1>R2 is established. With this developing roller, it is possible to obtain a high quality image and a high gradient.

Abstract: A toner-carrying roller such as a developing roller having a surface gloss of 2 or above, with the surface gloss of the black glass standard plate having a reflective index of 1.567 (according to DIN 67 530) being 100. The toner-carrying roller provides high-quality images free of density variation and fogging owing to its surface characteristics specified by the surface gloss. In addition, it keeps its good performance without deterioration in image quality for a long period of use.

Abstract: Disclosed is a developing roller to be employed in a developing device which is incorporated in electrophotographic apparatus such as printers, duplicators, receivers for facsimiles or the like, and in which toner carried on the surface of the roller being or not being kept in contact with a photoreceptor is transferred at least to the photoreceptor. The developing roller is characterized in that an elastic conductive layer is formed around the conductive shaft of the roller, that the outer surface of the elastic conductive layer is covered with a surface layer, and that the surface layer is formed from a resin composition of which the contact angle with a drop of a liquid consisting essentially of a component similar to the resin component constituting the toner to be used in the developing device is not smaller than 35.degree.. In the developing device, toner filming occurs little around the developing roller, and the initial density of the images formed is good.

Abstract: A developing device used in an image forming apparatus has a developing roller at a lower opening of a toner hopper, and the developing roller contacts a photosensitive drum to form a developing portion therebetween. The hopper stores nonmagnetic toner and is provided with a toner stirring member and a toner feed roller being in press-contact with the developing roller in a lower part of the hopper. A doctor blade contacts a circumferential surface of the developing roller on an upstream side of the developing portion in a rotation direction of the drum. A conductive scooping sheet contacts the circumferential surface of the developing roller on a downstream side of the developing portion. A residual toner not used to develop a latent image on the drum and left on the developing roller is passed under the sheet into the hopper with the rotation of the developing roller.

Abstract: A developing roller for use in an image forming apparatus using an electrophotographic process. The image forming apparatus includes a photosensitive drum having a transcribing roller cleaning device; the developing roller disposed between a transcribing device and an exposing device adjacent to the photosensitive drum, for frictionally charging toner at a place where the developing roller contacts with a supply roller and transferring the charged toner to a developing region so as to attach the charged toner to a latent image formed on the photosensitive drum; a regulating blade disposed between the developing region and the supply roller, for regulating a toner layer on the developing layer into a thin toner layer, being in contact with the developing roller; the supply roller in contact with the developing roller, for frictionally charging the toner transferred into a contact nip by a relative motion therebetween; and an agitator for transferring the toner in a toner cartridge to the supply roller.

Abstract: A cylindrical structural body for use in an image forming apparatus and a method of producing the same are disclosed. The structural includes a cylindrical sleeve and flanges or similar end members respectively affixed to opposite ends of the sleeve. The flanges can be firmly and easily affixed to the sleeve without causing the sleeve to deform. The structural body is therefore low cost and highly accurate.

Abstract: The toner supply roller 31 includes a roller shaft 31A made of metal, an inner spongy member 31B formed around the roller shaft 31A, and an outer spongy member 31C formed around the inner spongy member 31B. The inner spongy member 31B is formed of a closed cell foam material having electrically conductive properties. On the other hand, the outer spongy member 31C is formed of an open cell foam material having electrically conductive properties. Therefore, toner particles will not enter the cells formed in the inner spongy member 31B even after the toner supply roller 31 has been used for a long time.

Abstract: A developing roller 19 is formed of a blend material produced of silicone rubber and EPDM, which has good abrasion proof, and subjected to a rubbing process to rub a surface of the developing roller 19 until convex portions 19A formed on the surface become less than two times a particle diameter (5-10 .mu.m) of toner T, i.e., 10-20 .mu.m. Accordingly, the surface condition of the developing roller is not changed for a long time and thus the toner T can uniformly be carried on the surface of the developing roller 19, forming a uniform thickness toner layer, thereby enabling to uniformly charge the toner layer. Uniformly charged toner layer on the surface of the developing roller 19 thus makes it possible to develop an electrostatic latent image formed on a photosensitive drum 12 with uniform toner density, causing no difference in toner density. When the developed image on the photosensitive drum 12 is transferred to a sheet 50, a resultant image with uniform image density can be formed on the sheet 50.

Abstract: An electroconductive elastic member including an electroconductive material prepared from a polyurethane foam or polyurethane elastomer using a polyester polyol and a quaternary ammonium salt to impart electroconductivity. The polyurethane foam or polyurethane elastomer can be produced using, as a polyisocyanate component, a hydrogenated product from diphenyl-methane diisocyanate, hexamethylene diisocyanate, or any of various modified diphenylmethane/hexamethylene diisocyanate The elastic member may be used in an electrophotographic apparatus. Thus the member is well suited for producing an elastic roller with intermediate electric resistance in an electrophotographic process.

Abstract: In a developing device for an image forming device, such as a laser printer, a supply roller is in rolling contact with and supplies toner particles to a developing roller which in turn is in rolling contact with a photosensitive drum and supplies toner particles to an electrostatic latent image formed thereon. The developing roller and the supply roller press against each other with a slight pressure. The supply roller has a resilient outer form layer formed from a silicone foam or urethane foam and fluororesin particles are dispersed within the foam. With the dispersion of the fluororesin particles throughout the resilient outer form layer of the supply roller, toner particles can be better charged by contact between the resilient outer foam layers of the supply roller and the developing roller. As a result, improper image development is less likely to occur and the developing roller will not scratched or otherwise damaged.

Abstract: There are disclosed an electroconductive member comprising a high-molecular material, e.g. polyurethane as a matrix and a quaternary ammonium salt of an organic acid, e.g. bis-or-mono(quaternary ammonium) oxalate; and an electrophotographic apparatus which makes use of the electroconductive member, especially in the form of an electroconductive roller as a developing member, image transfer member, etc. The electroconductive member, when used in electrophotographic mechanism, minimizes an increase in electric resistance at the time of normal continuous passage of an electric current and also variation range in the electric resistance between the circumstances of low temperature/humidity and those of high temperature/humidity.

Abstract: A developing roller is adapted to carry a developer on its surface and come in contact with or close to a photoconductor drum having an electrostatic latent image borne on its surface whereby the developer is supplied to the drum to visualize the latent image. The developing roller includes a highly conductive shaft and an elastic layer with conductivity formed around the shaft. The elastic layer is surface treated so as to have a resin component which contains a urea resin and/or melamine resin. The roller satisfies log(R.sub.2 /R.sub.1).ltoreq.4.5 wherein the untreated roller has a resistance R.sub.1 and the roller with the resin component has a resistance R.sub.2. The developing roller does not contaminate the photoconductor drum and ensures that images of quality are reproduced without a density variation and background fog over a long time.

Abstract: A developer carrier comprising a cylindrical support having provided on the outer surface thereof a coating layer for retaining a developer, wherein the coating layer comprises electrically conductive fine particles and a binder resin comprising a phenolic resin having a weight-average molecular weight of from 3,000 to 5,000 as determined before being crosslinked. Also disclosed is a developing apparatus which comprises a developer carrier for retaining a developer on the surface thereof and for conveying the developer onto the position at which an electrostatic latent image formed on a latent image carrier is developed, wherein the developer carrier comprises a cylindrical support having provided on the outer surface thereof a coating layer for retaining a developer, wherein the coating layer comprises electrically conductive fine particles and a binder resin comprising a phenolic resin having a weight-average molecular weight of from 3,000 to 5,000 as determined before being crosslinked.

Abstract: A developing device includes a developing sleeve for bearing and conveying a magnetic developer, a magnet provided within the developing sleeve, and magnetic members, provided so as to face end portions of the developing sleeve with a gap, for forming a magnetic seal by a magnetic field formed between the magnetic members and the magnet. The magnet or each of the magnetic members has a plurality of grooves for forming a leakage magnetic field.

Abstract: In a developing device according to the present invention, a developer carrying member in which a dielectric layer is formed on the surface of a conductive base substrate is used. In conveying a monocomponent developer containing no carrier to a developing area opposite to the image carrying member with the developer held on the surface of the developer carrying member, to develop a latent image formed on the image carrying member by the developer, the dielectric layer in the developer carrying member satisfies the following conditions:t.gtoreq.50, .di-elect cons..ltoreq.10, and 15.ltoreq.t/.di-elect cons..ltoreq.35where t (.mu.m) is the thickness of the dielectric layer, and .di-elect cons. is the relative dielectric constant of the dielectric layer.

Abstract: A developing device according to the present invention has a developer carrying member for conveying a developer to a developing area opposite to an image carrying member with the developer held on its surface and a controlling member for controlling the amount of the developer conveyed to the developing area upon being pressed against the surface of the developer carrying member, the surface of the developer carrying member and/or the surface of the controlling member pressed against the surface of the developer carrying member being composed of an elastic material having a rubber hardness of 20.degree. to 70.degree. and having elongation of 400 to 1200%.

Abstract: An electrophotographic type image forming device having a developing roller and a photosensitive drum. A nip portion is provided therebetween for supplying developing agents from the developing roller to the photosensitive drum. The developing roller and the photosensitive drum are rotated in the same rotational direction, i.e, a peripheral moving direction of the developing roller is opposite to peripheral moving direction of the photosensitive drum at the nip portion, so that toners provide vivid mobility at or adjacent the nip portion so as to cancel Van der Waals attraction force, and so that the toners can be attracted to the photosensitive drum only by applied electrical field. Developing is performed immediately upstream of the nip portion in rotational direction of the developing roller, and residual toners are collected by the developing roller immediately downstream of the nip portion for collecting and reusing the residual toners.