Abstract: A developing apparatus is so adapted that in performing development upon converting a developer to a developing area opposite to an image carrying member by a developer carrying member with the developer held on the surface of the developer carrying member as well as alternately repeating an exertion period during which an AC electric field is exerted between the developer carrying member and the image carrying member and a stop period during which no AC electric field is exerted, the AC electric field is exerted in such a manner that the directions of the first and last electric field portions of the AC electric field in one exertion period are the same, and the direction of the last electric field portion of the AC electric field in the exertion period and the direction of the first electric field portion of the AC electric field in the subsequent exertion period after an elapse of the stop period are the same.

Abstract: A color image forming device and method wherein latent images are formed on an image carrying body and a plurality of developing devices are employed to develop the latent images in respective colors. During development, a revolver device moves one of said developing devices to a developing position confronting the image carrying body, a developing bias applying device applies developing biases to a developer carrying body of the developing device at the developing position, a potential sensor detects a potential of the image carrying body, and a bias controller changes a first developing bias to a second developing bias while one of the developing devices is moved to the developing position confronting the image carrying body, the second developing bias being decided according to the detected potential by the potential sensor.

Abstract: A donor roll for transporting marking particles to an electrostatic latent image recorded on a surface is provided. The donor roll is adaptable for use with an electric field to assist in transporting the marking particles from the donor roll to a development zone adjacent the surface. The donor roll includes a rotatably mounted body and a first electrode member mounted on the body. The donor roll further includes a second electrode member mounted on the body and spaced from the first electrode member and a resistive member electrically interconnecting the first electrode member and the second electrode member so that when an activation potential for creating an electric field is applied to the first electrode member a portion of the potential will be transferred to the second electrode member creating an attenuated field.

Abstract: In a developing apparatus, a developing roller has a toner layer formed on a surface thereof, which toner layer is brought into contact with a photoconductor. A magnetic conveying roller having a magnet body is arranged rotatively close to the photoconductor. A regulating plate is provided at an outer periphery of the conveying roller.

Abstract: There is disclosed a compact design for the electronic circuits required to provide electrical contact to a SED roll of a segmented electrode development unit. In this invention, all the required high voltage and low voltage circuitry is placed on a printed flexible circuit which is folded and rolled into a cylindrical circuit to be connected to the SED roll. The flexible printed circuit has a plurality of output terminals each of which will be connected to one of the electrodes of the SED roll. In this invention, a spool is used to support the connection of the cylindrical circuit to the SED roll.

Abstract: A voltage that has a difference in potential in the polarity direction opposite to the charge of the developer relative to the voltage applied to the sleeve by power supply 34 is applied to the control member by power supply 36. By this use of power supply 36, when the amount of remaining developer has fallen to a prescribed level, the conveyance of the developer to the photosensitive member by the sleeve is prevented, preventing image formation. Therefore, the image formation operation does not continue where the amount of remaining developer is small, which in turn eliminates the scattering of developer and maintains the cleanliness of the interior of the apparatus.

Abstract: A developing apparatus includes a rotatable developer carrying member for carrying a developer; an electrode to be supplied with a bias voltage; a coil spring, provided in an end portion of the developer carrying member, for electrical connection between the electrode and the developer carrying member.

Abstract: A developing apparatus forms multiple toner layer and stably obtains predetermined toner charging amount and toner layer thickness, and further uniformly supplies the toner onto the toner carrying roller along its entire length. In the developing apparatus, a brush-like toner supplying roller having brush fibers and a second toner supplying roller are disposed at a predetermined interval and respectively brought into contact with a developing roller. The brush-like roller is first brought into contact with the developing roller after passing through the developing area on a photosensitive body opposing thereto, and the brush-like roller rotates in an inverse rotational direction to that of the developing roller at the contact position. The second roller is brought into contact with the developing roller after passing through the contact position with the brush-like roller, and rotates in a same rotational direction as that of the developing roller at the contact position.

Abstract: In an image forming apparatus, a developing device includes an upper and a lower feed roller intervening between a developing roller and a toner hopper and contacting the developing roller. The upper and lower feed rollers feed toner to the developing roller. The two rollers rotate in opposite directions to each other in order to move the toner existing therebetween from the hopper side to the developing roller side. The device is capable of forming a laminate developer layer of uniform charge and uniform thickness on the developer carrier, and eliminating the need for a seal member between a casing and the developer carrier or simplifying its configuration.

Abstract: An image forming apparatus has an image bearing member, charging means for uniformly charging the image bearing member, electrostatic image forming means for forming an electrostatic image on the image bearing member charged by the charging means, developing means for developing the electrostatic image on the image bearing member with a toner and also recovering any residual toner on the image bearing member, and transferring means for transferring the toner image to a transfer member conveyed. Upon re-operation after jam, at least one full rotation of the image bearing member effects the recovery of the toner on the image bearing member by the developing means with the charging by the charging means being rendered OFF.

Abstract: A developing apparatus includes a developing roller which rotates along with the photosensitive drum on which an electrostatic latent image is formed, and feeding toner to be adhered to the electrostatic latent image formed on the photosensitive drum, a conductive blade for uniformly limiting the thickness of the toner put on the developing roller, and a first high-voltage generator for generating a development bias voltage of -200 V which is supplied to the developing roller and biases the potential of the toner. Particularly, the developing apparatus further includes a second high-voltage generator for generating a blade voltage of -300 V which is supplied to the conductive blade and electrostatically charging the toner to compensate for a shortage of the electrostatic charge obtained in the toner by friction on the developing roller.

Abstract: A donor roll for transporting marking particles to an electrostatic latent image recorded on a surface is provided. The donor roll includes a rotatably mounted body and an electrode member mounted on the body. The donor roll further includes a magnetically permeable core external to the body. The core rotates with the body. The core is composed of a plurality of wires. The donor roll further includes an electrically conductive material positioned on the core. The material is electrically connected to the electrode member.

Abstract: A commutating connector which electrically connects conductive paths of a rotating electroded donor roll to a voltage source. The connector includes a housing made of an electrically insulating material. The housing defines a chamber to receive the donor roll. An electrically conductive brush is disposed in the chamber. The brush is mounted in pressing engagement against the conductive paths on the electroded donor roll to electrically connect the voltage source to the conductive paths on the electroded donor roll. The chamber is divided by a partition into a commutating and a non-commutating area. The housing has ports for receiving air to prevent particulate matter from accumulating between the brush and donor roll.

Abstract: A non-interactive or scavengeless development system for use in color imaging. To control the developability of lines and the degree of interaction between the toner and receiver, an AC voltage is applied between a donor roll and two sets of interdigitated electrodes embedded in the surface of the donor roll to enable efficient detachment of toner from the donor to form a toner cloud. An optical switching arrangement effects an electrical connection between a slip ring and one set of interdigitated electrodes. The optical switch uses photoconductor elements, each having a geometry that results in an optical switching device having a larger capacitance and therefore capable of effecting switching at lower current densities.

Abstract: A developing device for use with an image forming apparatus that is capable of reliably preventing the entry of large particles of developing agent between a layer thickness limiting member and a developing agent carrier. The developing device includes an image carrier and a developing agent carrier that conveys a developing agent to the vicinity of the image carrier. The developing agent is conveyed to the vicinity of the image carrier. A layer thickness limiting member limits a thickness of a layer of the developing agent. The layer thickness limiting member includes a columnar member having a ridge line closely parallel to the surface of the developing agent carrier. The ridge line limits the thickness of the developing agent layer.

Abstract: A development system which includes a flexible donor belt having groups of electrode array near the surface of the belt is disclosed. The Electrode array has group areas in which perform the function of: Loading; Transferring; Developing; Transferring and Unloading. Each electrode array group area is independently addressable and operatively connected to voltage source in order to supply a voltage in the order of .quadrature.0-1000 volts AC or DC to each group area. The electrodes array group area picks up the toner from the magnetic brush. An electrode array group area connected to the voltage source via phase shifting circuitry such that a traveling wave pattern is established.

Abstract: In an image forming apparatus, a developing device operable with toner or single component type developer has a hard first developing roller and a soft second developing roller. Fine magnetic N-S poles are formed on the periphery of the first roller. The second roller conveys the toner, electrostatically transferred thereto from the first roller, to an image carrier. The device frees a toner image from deterioration due to toner particles charged to a polarity opposite to an expected polarity. The toner forms a uniform thin layer on the first roller and is uniformly charged. Toner for use with this type of developing device is also disclosed.

Abstract: An electroded donor roll development unit including an electroded donor roll assembly for mounting partially within a mixing chamber of a housing of the development unit for forming a development nip with an image bearing member, and for moving charged toner particles from the mixing chamber to the development nip. The electroded donor roll assembly includes a donor roll having a dielectric layer, and axially extending electrodes formed in the surface of the dielectric layer. The donor roll assembly also includes a bias voltage source for biasing the electrodes and a tri-contact commutator or assembly mounted on the donor roll and connected to the bias voltage source for commutating a bias voltage to the electrodes while significantly reducing and eliminating risk of sporadic electrical arcing during bias commutation.

Abstract: A developing apparatus is capable of providing stable charging ability for a developer and stable transfer ability for transferring the developer to a photoreceptor for electronic photography to prevent residual positive images and stain of texture which appear on a toner image. A first toner transfer roller 23 has a core supported to be rotatable and a sheet type insulation layer wound around the outer periphery of the core. The insulation layer is made of elastic rubber in which magnetic material having a specified particle size is uniformly dispersed and the magnetic material is formed with ferromagnetic substance such as magnet and magnetized in advance. The first toner transfer roller 23 attracts toner T by actuating magnetism on the insulation layer since the magnetic material added to the insulation layer is magnetized.

Abstract: An electrophotography developing apparatus of non-contacting type using a nonmagnetic one-component toner is provided. The developing apparatus adopts a soft roller as a developing roller and a developing gap of 50-200 .mu.m is formed between a developing drum and developing roller. A desirable image can be provided by adopting the soft roller as the developing roller and properly setting the developing gap between the developing roller and the developing drum. Generally, the electrophotography developing apparatus is used in the apparatus for printing and communicating, such as a duplicator, a printer and a facsimile.

Abstract: An toner cartridge and bias contact which pertains to the recharging of the cartridge by the development of a new way of making this electrical connection between the developer roller and the printer contact, in a most unique and simple way. In the best embodiment, an annular contact rides in the bore of the developer roller, pushed up against a stop where the bore diameter decreases, and the annular contact is tightly placed to attain accuracy, solidity, maximum contact and position. Also, a spring type contact may be used to set the gap of the doctor blade, controlling the distance between the developer roller and doctor blade. Alternately, a similar contact is attached to the end-felt roller seals of the developer roller. Electrical resistance has been provided to vary this bias voltage when desired and may even be added to the contact in the form of a resistant coating.

Abstract: A developing apparatus in which a nonmagnetic carrier is used; a developer forward member having a conductive surface and forwarding a nonmagnetic toner and the resin carrier by stirring is disposed so as to confront a toner carrying body with a gap interposed therebetween and so as to arrange a part of the surface thereof close to an inner wall surface of a frame of the apparatus, the frame having a surface profile corresponding to a surface profile of the forward member; and a voltage applying means is arranged so that the voltage applying means applies such a voltage to generate an electric field for attracting the toner in the developer toward the toner carrying body and attracting the resin carrier toward the developer forward member in the area where the toner carrying body confronts the developer forward member.

Abstract: An electrostatic recording apparatus including a recording medium which forms a latent image of a recording picture and then forms the recording picture, a charger which uniformly charges the recording medium, an imaging unit which forms an electrostatic latent image onto the uniformly charged recording medium, a developer which develops the electrostatic image formed on the recording medium and forms the recording picture, the developer including a development roller, and an electric field generator arranged near the developer to generate an electric field orthogonal to a rotating direction of the development roller.

Abstract: In an image forming apparatus, a developing device has an intermediate developing roller or belt between a developing roller and a photoconductive element. A high-tension power source applies a bias to the intermediate developing roller or belt. The bias before the start of printing is preselected to be zero volts, a voltage opposite in polarity to a charge potential deposited on the photoconductive element, or a voltage identical in polarity with the charge potential and smaller in an absolute value of potential than a potential deposited on the photoconductive element after exposure.

Abstract: A back electrode roller is connected to a back voltage applying circuit. When a sheet of paper is not located at a position corresponding to toner passage apertures, or when a non-printing portion of the sheet of paper is located at the position corresponding to the apertures, an inhibiting voltage for preventing attraction of the toner is applied from the back voltage applying circuit to the back electrode roller. Accordingly, even when the toner erroneously passes through the apertures, the attraction of the toner toward the back electrode roller can be prevented by the application of the inhibiting voltage.

Abstract: An image forming apparatus includes an image bearing member for bearing an electrostatic latent image; developer carrying member for carrying a developer comprising toner particles; a voltage source for applying to the developer carrying member an oscillating voltage having a predetermined frequency; wherein the following is satisfied:.vertline.Vpp-2Vcont.vertline./16Vf.sup.2 <d.sup.2 /.vertline.Q.vertline.where Vpp (V) is a peak-to-peak voltage of the oscillating voltage, Vf (Hz) is the frequency of the oscillating voltage, Vcont (V) is a potential difference between a voltage of a DC component of the oscillating voltage and a potential of an image portion on the image bearing member when a maximum image density is provided, Q (c/kg) is an average triboelectric charge amount of the toner particles, and d (m) is a gap between the image bearing member and the developer carrying member.

Abstract: An electrophotographic development apparatus capable of maintaining the surface roughness of a developer roller thereof for a long term or even for the life span of the apparatus. The developer roller includes an elastic layer, formed on a core metal shaft, and made of a rubber elastic material with additional insulating micro-powder of 30 to 200 parts having a particle diameter in a range of 1 to 50 micrometers, where the amount of the rubber elastic material constitutes 100 parts. During a printing operation, the insulating micro-powder drops from the elastic layer as the rubber elastic material is worn, so that the developer roller can maintain its surface roughness in proportion to the particle diameter of the dropped powder.

Abstract: In an apparatus in which a yellow, magenta, and cyan toner images are superimposed on a photoreceptor drum made of a transparent material, an image exposure device is provided in the photoreceptor drum and emits exposure lights whose wavelength has a spectral reflective ratio lower than 30% for at least two of yellow, magenta, and cyan toners. The image forming processes is controlled so that a toner image for which the exposure lights have a spectral reflective ratio larger than 30% is formed after toner images for which the exposure lights have a spectral reflective ratio lower than 30% have been formed.

Abstract: A donor roll for transporting marking particles to an electrostatic latent image recorded on a surface is provided. The donor roll is adaptable for use with a power source to assist in transporting the marking particles. The donor roll includes a rotatably mounted body having a particle transportation portion, a support portion adjacent the particle transportation portion, and an external portion adjacent the support portion and spaced from the particle transportation portion. The donor roll further includes an electrode member mounted on the body and an electrical connector associated with the support portion of the body and electrically connected to the electrode member. The electrical connector is adapted to be electrically connectable to the power source.

Abstract: A developing device for use in an image forming apparatus like a copying machine or printer that develops an electrostatic latent image formed on an electrostatic latent image carrier to obtain a visible image. In the developing device, a toner charge erasing member contacts with the surface of a developing agent carrier and is connected to a power supply which applies developing bias voltage, so that a toner charge erasing bias voltage is applied to the toner charge erasing member from the power supply. A connection circuit provided between the toner charge erasing member and the power supply to maintain a constant electric potential difference between the developing bias voltage and the toner charge erasing bias voltage.

Abstract: A donor roll for transporting marking particles to an electrostatic latent image recorded on a surface is provided. The donor roll is adaptable for use with an electric field to assist in transporting the marking particles from the donor roll to a development zone adjacent the surface. The donor roll includes a rotatably mounted body and a first electrode member mounted on the body. The donor roll further includes a second electrode member mounted on the body and spaced from the first electrode member and a resistive member electrically interconnecting the first electrode member and the second electrode member so that when an activation potential for creating an electric field is applied to the first electrode member a portion of the potential will be transferred to the second electrode member creating an attenuated field.

Abstract: An image forming apparatus having a developing device which develops an electrostatic latent image formed on an electrostatic latent image carrier to obtain a visible image. The developing device includes a charge erasing member that erases the electrical charge of residual toner on a developing agent carrier by a charge erasing bias voltage applied thereto. When exposure or not developing is not performed in the image forming apparatus, the charge erasing bias voltage is applied to the charge erasing member. While, during exposure or developing, the charge erasing bias voltage is not applied to the charge erasing member for preventing leaks or discharge phenomenon between the charge erasing member and the developing agent carrier.

Abstract: A donor roll for transporting marking particles to an electrostatic latent image recorded on a surface is provided. The donor roll is adaptable for use with an electric field to assist in transporting the marking particles. The donor roll includes a rotatably mounted body. A portion of the body is electrically conductive. The donor roll also includes a dielectric layer mounted on a portion of the electrically conductive portion of the body. The donor roll also includes a first electrode member mounted on the body, adjacent the dielectric layer, and spaced from the electrically conductive portion of the body so that when the electric field is applied to the first electrode member a portion of the field will be transferred to the dielectric layer.

Abstract: A donor roll for the conveyance of toner in a development system for an electrophotographic printer includes an outer surface of phenolic resin. The resin is doped to a suitable conductivity to facilitate a discharge time constant thereon of less than 300 microseconds. The donor roll is used in conjunction with an electrode structure as used in scavengeless development.