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: An image forming apparatus has a photoreceptor drum and a developing roller supported in the developing unit for retaining and conveying the developer, and further has a sealed viscous fluid damper having a viscous fluid sealed therein, arranged coaxially with the rotary shaft of the photoreceptor drum.

Abstract: An image-forming apparatus is provided with: a photoconductor drum having a surface on which a toner image is formed, a transfer drum for transferring the toner image onto a copying material by allowing the copying material to contact the photoconductor drum, and a ground roller for electrostatically attracting the copying material onto the transfer drum prior to transferring the toner image onto the copying material. He transfer drum is constituted by a semi-conductive layer and a dielectric layer that are stacked on a conductive layer. [Supposing that] The nip width between the photoconductor drum and the transfer drum is L1, the rotation speed of the two drums is Vp, and the time constant, which is represented by a product of the resistance and the capacitance between the two drums, is .tau., the relationship represented by L1/Vp<.tau. is satisfied.

Abstract: A blade is pressed against a developing roller for regulating the amount of toner which is deposited on a surface of the developing roller. The blade is formed with a slant face at its tip end, to which the toner is transported along a direction of rotation of the developing roller. An angle of aperture .theta. at a toner inlet portion defined by the developing roller and the slant face is set at 12.5.degree. or more, the angle of aperture counting in an angle .psi. of the slant face, elastic deformation and radius (R) of the developing roller, and an angle .alpha. related to a nip width w on which the blade contacts with the developing roller. Such an angle of aperture .theta. provides a great allowance for a free length l of the blade, thereby permitting the blade to maintain a constant toner mass for forming a uniform toner layer.

Abstract: For realizing a satisfactory and stable developing process, the charge state of a developer and the density of toner particles contained in the developer is kept constant in the developing process. A developing roller to be driven rotationally is provided in a developing tank containing a developer. The developer is sucked magnetically using the magnetic force of a magnet provided in a developing sleeve composing the developing roller. The developer is then fed into a developing area opposed to a photosensitive member, then collected into the developing tank after the developing process is ended. The magnet is composed of an odd number of magnetic poles; developing pole, feeding pole, magnetic force distribution adjusting pole, developer sucking pole, developer separating pole, auxiliary collecting pole, and collecting pole. Between the sucking pole and the developing pole, an even number of poles are disposed. Between the developing pole and the separating pole are disposed an even number of poles.

Abstract: The object of the invention is to certainly remove and certainly recover the charged toner remaining on a developing roller after development. A single component toner which is delivered to the developing roller via a toner-supplying roller is made into a relatively thin layer of a predetermined thickness with a charging plate and is frictionally charged with a given quantity of electric charge. Subsequently, the toner is adhered on a photoreceptor drum along by the electrostatic latent image to develop an image at the developing region at which the developing roller comes into contact with the photoreceptor drum. After development, the electric charge of the toner layer on the developing roller is removed with an electric-charge-removing sheet. The toner after development is recovered into a toner hopper via the toner-supplying roller.

Abstract: To prevent scattering of toner when an image forming operation is started and ended in a developing process using one-component toner, a rotatable developing roller in contact with a photosensitive member carrying a static latent image, which is used to carry and feed one-component toner, is provided in a developing tank containing one-component toner. Initially, toner is fed to a feed roller, then passed through a toner restricting member which is pressed against the developing roller to restrict the amount of toner to be fed, so that a layer of toner is formed at a fixed thickness and fed into a developing area in contact with the photosensitive member. Thus a static latent image is produced on the developing roller. In this process, a developing bias voltage Va is supplied to the developing roller, a restricting voltage Vb is supplied to the toner restricting member so as to fix the thickness of the toner layer, and a supply voltage Vc is supplied to the feed roller to control the supply of toner.

Abstract: An image-forming device according to the present invention is provided with an image-carrying body, a transfer medium, which transfers the toner image formed on the image-carrying body to a transfer material, and an affixing body provided at the perimeter of the transfer medium, which electrically affixes and holds the transfer material to the transfer medium. The transfer medium is made up of at least a semiconducting layer and a conductive substrate supporting it. The semiconducting layer has a foam portion with foam particles which increase in diameter toward the conductive substrate. This foam portion is made of a dielectric sheet, which is manufactured by forming a foaming dielectric polymer into a sheet, and heating the two surfaces thereof at different temperatures. The foregoing structure can provide a desired elasticity with the portion with foam particles of large diameter, and a desired surface smoothness with the portion with foam particles of small diameter.

Abstract: A developing unit incorporated in an image forming apparatus and having a waste toner container for collecting a waste toner and a fresh toner container containing a fresh toner and adjoining the waste toner container. When the waste toner container is filled with the waste toner, the developing unit causes the waste toner to enter the fresh toner container while preventing the fresh toner from entering the waste toner container. A wall separates the waste toner and fresh toner containers from each other and is formed with an opening. A shutter is associated with the opening and opens when the pressure inside the waste toner container increases due to the waste toner. The waste toner which enters the fresh toner container via the opening is agitated together with the fresh toner as far as possible and then fed to a developing roller or is collected in a container whose volume is variable.

Abstract: A developing device of one-component developing type for use in the electrophotographic copying machine capable of developing latent image on the image carrier. The device comprises a developer carrying member having resistor layer on its surface layer, a regulation member for regulating the thickness of developer disposed on the developer carrying member, a replenishing member for replenishing developer onto the developer carrying member after finishing a process of developing, and a removing member for removing developer remaining on the developer carrying member after finishing a process of developing. The device sets the relationship of the time constants and the operational time periods in the form of inequalities, in order to obtain an optimum condition of developing. There are nine methods of setting the combination of time constant(s) and the operational time periods so as to satisfy the respective inequalities mentioned in the description of the invention.

Abstract: An apparatus having a plurality of replaceable parts. Replaceable parts to which the same life is assigned beforehand are replaced at the same time by hand or by use of a jig. Lives which are integral multiples of the shortest life which one of the replaceable parts has each is assigned to respective one of the other replaceable parts. Hence, when the life of a certain part has expired, the part having the shortest life is automatically replaced together with the part whose life has expired. The replaceable parts each is mounted on and locked to the apparatus and, when the life thereof has expired, unlocked from the apparatus. The expiration of the life is detected either electrically or mechanically, and the parts reached the end of the life is indicated. Before the life of a replaceable part expires, a spare part for replacing it is prepared by detecting that the life is about to expire. The deterioration of a part having a comparatively long life is measured to correct the time for replacing it.

Abstract: An image developing device for use in an electrophotographic copying apparatus or a printer includes a developing roller for supplying toner to a latent image formed on a latent image carrier to develop the latent image into a visible toner image. The image developing device also includes a toner supply roller independently rotatable in abutting engagement with the developing roller for supplying the toner onto the developing roller. Each of the toner supply roller and the developing roller is electrically conductive. An electric potential with its polarity dependent on whether the toner is positively or negatively chargeable is applied between the toner supply toner and the developing roller by a bias voltage distributing circuit.

Abstract: An electrophotographic image developing device includes a fixed rotatable member and a suspended rotatable member reciprocally movable toward and away from the fixed rotatable member. Rotative power from a drive source is transmitted to the suspended rotatable member through a power transmitting unit which includes a coupling capable of absorbing axial misalignment between driver and driven shafts.

Abstract: A developing device includes a developing sleeve driven to rotate for transporting a film of charged developer as carried thereon past a developing station where the film of developer is applied to an electrostatic latent image to have it developed. Also provided is a sponge roller pressed against and driven to rotate in the same rotating direction as that of the developing sleeve, so that the developer is supplied to the developing sleeve at one side of the contact between the developing sleeve and the sponge roller and any residual developer on the developing sleeve is removed at the other side of the contact. Preferably, a desired voltage difference is established between the developing sleeve and the sponge roller. Furthermore, the sponge roller is preferably so structured to have a sufficient conductivity level at least at its outer peripheral surface thereby allowing the residual charge on the developing sleeve to be discharged sufficiently.

Abstract: An electrostatic latent image developing apparatus supplies toner to a latent image carrier such as a drum-shaped photosensitive body to visualize a latent image formed thereon. The toner is supplied by a rotating drum-shaped toner carrier having a portion confronting the photosensitive body adjacent thereto and another portion held in contact with toner contained in a toner container. The toner is electrostatically attracted to the toner carrier and transferred therefrom to the photosensitive body. The toner on the toner carrier is regulated into a thin toner layer by a toner layer regulating member that is resiliently held in sliding contact with the toner carrier. To prevent toner deposits from being attached to the toner layer regulating member, the toner layer regulating member is made of a material adapted to wear with the attached toner.