Abstract: When superimposing toner images of a plurality of colors on an image supporting member to form a color image, a free phase ion in a precedent image is removed without distorting the toner image precedently formed on the image supporting member, thereby improving reproducibility of image dots of the toner images having second and subsequent colors to obtain a high-definition color image with high contrast.

Abstract: A charge removing unit is provided in order to control the surface potential of an image bearing element by removing charge from a surface of the image bearing element before a toner image is transferred from the image bearing element to a transfer medium. Surface potential controlling units are provided upstream of a contact area between the image bearing element and the transfer medium in order to control the surface potential of the transfer medium so that a toner on the image bearing element does not shift to the transfer medium.

Abstract: An image forming apparatus has a movable image bearing member, a image forming device for forming a developer image on the image bearing member, and an intermediate transfer member on which the developer image on the image bearing member is transferred while it is moving at a predetermined surficial moving speed different from the surficial moving speed of the image bearing member. The image forming apparatus forms a predetermined image prior to formation of a normal image.

Abstract: An image forming apparatus having a photoconductor for carrying a toner image; a transfer device, provided with a discharge wire, for transferring the toner image onto a transfer material through discharge in a transfer area, after a transfer material is superposed with the photoconductor; a transfer-exposure device for carrying out light exposure of a surface of the photoconductor superposed with the transfer material, in the transfer area; a separator for separating the transfer material from the photoconductor after the toner image is transferred; and a controller for controlling the image forming apparatus. The controller controls such that light from the transfer-exposure device is applied to the photoconductor surface for the first time when the photoconductor surface superposed with the transfer material has reached the transfer area.

Abstract: An electrophotographic printer including a pre-erasing unit. The pre-erasing unit includes a pre-erasing lamp to irradiate light, and a pre-transfer erasing lens to induce the light generated from the pre-transfer erasing lamp to the photosensitive drum, movably installed such that it moves to an erasure position at which the pre-transfer erasing lens is close to the photosensitive drum for erasure, and moves to a retracted position spaced apart from the photosensitive drum so as not to interfere therewith when the photosensitive drum unit is being mounted or dismounted. The pre-erasing unit may further include an elastic member to provide elasticity in a direction in which the pre-transfer erasing lens moves to the retracted position.

Abstract: Provided is an image forming apparatus, including: a movable image bearing body; an image forming unit for forming a developer image on the image bearing body; a transferring unit for transferring the developer image formed on the image bearing body onto a moving transferring medium; and a control unit for controlling the image forming unit to form a predetermined image composed of a dot image with a predetermined density prior to formation of a normal image, in which a composite image is formed from the normal image and the predetermined image in an area where the normal image is to be formed, and the dot image is formed in a dot area having the normal image and the predetermined image overlapped with each other, with a density determined on the basis of a relationship between a density of the normal image and the predetermined density in the dot area.

Abstract: An image forming apparatus has a latent image forming portion for forming an electrostatic latent image on an image bearing member; a plurality of developing portions for developing the electrostatic latent image on the image bearing member with a developer; a primary transferring portion for transferring by sequentially superposing each developer image developed by the plurality of developing portions on an intermediate transferring member; a secondary transferring portion for collectively transferring onto a transferring material the developer images transferred by being superposed on the intermediate transferring member; and a charging portion for charging the developer images on the image bearing member; wherein the charging portion decides a charging condition in accordance with the order of transferring the developer images onto the intermediate transferring member.

Abstract: An image forming apparatus includes a developing device having a photosensitive element rotating in a given direction to form a latent electrostatic image on a surface thereof through a laser scanning unit, and a developing roller developing the latent electrostatic image into a toner image using a developer, a transfer part transferring the toner image onto a transported printing paper disposed on a paper-transporting path to engage the photosensitive element, and a subsidiary transfer part having at least one light source disposed on at least one of both sides of the paper-transporting path to expose the photosensitive element to light and thereby to enhance a transfer efficiency, and an optic fiber guide disposed longitudinally along the photosensitive element to lead the light generated from the light source to the photosensitive element.

Abstract: In a color electrostatographic printer apparatus having a plurality of tandem stations for applying respective color separation toner images to a receiver member, and a clear toner station for providing a clear toner overcoat to a multicolor toner image formed by the respective color separation toner images on the receiver member, a controller is provided that selectively controls deposition of clear toner to the multicolor toner image so that greater amounts of clear toner are deposited in image areas of the multicolor toner image having relatively higher density color and relatively lesser amounts of clear toner, including no clear toner, are deposited upon image areas of the multicolor toner image having relatively lower density color.

Abstract: An image forming apparatus has a movable image carrier for carrying a toner image thereon; an image forming section for forming the toner image on the movable image carrier; a transfer section for electrostatically transferring the toner image on the movable image carrier to a transfer medium at a transfer position; an electrifying section for electrifying the toner image on the movable image carrier before the toner image reaches the transfer position; and a bias applying section for applying a bias to the electrifying section. This image forming apparatus controls the bias output of the bias applying section in accordance with information about surface roughness of the transfer medium.

Abstract: As an urging member 50 urges a front surface side roller 48 against a back surface side roller 45, the front surface side roller 48 and the back surface side roller 45 bring an intermediate transfer belt 41 and a recording medium 4 into pressure contact with each other at a secondary transfer position 49. The thermal capacity per unit surface area of each one of the front surface side roller 48 and the back surface side roller 45 is larger than the thermal capacity per unit surface area of the intermediate transfer belt 41. Further, the thermal capacity per unit surface area of the back surface side roller 45 is larger than the thermal capacity per unit surface area of the front surface side roller 48.

Abstract: An electrographic printing machine including: a first photoconductive member; an imaging device for recording a first latent image on the first photoconductive member to form a first developed image; a first developer unit for developing the first latent image; a second photoconductive member, closely adjacent to the first photoconductive member in a transfer region; a second imaging device for recording a second latent image on the second photoconductive member; a second developer unit for developing the second latent image to form a second developed image; a first transfer station for transferring the second developed image on the second photoconductive member to the first photoconductive member; and a second transfer station for transferring developed images on the first photoconductive member to a recording substrate.

Abstract: An image forming apparatus has a movable image bearing member, a image forming device for forming a developer image on the image bearing member, and an intermediate transfer member on which the developer image on the image bearing member is transferred while it is moving at a predetermined surficial moving speed different from the surficial moving speed of the image bearing member. The image forming apparatus forms a predetermined image prior to formation of a normal image.

Abstract: An apparatus for digitally generating an image comprises a photoconductor assembly, a corona assembly, and a light source assembly to generate a latent image on the photoconductor. The apparatus also includes a developer assembly that includes a developer, such as powder paint, to generate an image. The apparatus may include a fuser for generating a film image. The apparatus of the present invention may include a cartridge for storing and digitally applying adhesive to the image. Furthermore, the apparatus of the present invention includes a controller for selectively controlling voltages to control thickness of the image. Additionally, apparatus may include a consumable sheet to remove excess adhesive from the substrate.

Abstract: Provided is an image forming apparatus, including: a movable image bearing body; an image forming unit for forming a developer image on the image bearing body; a transferring unit for transferring the developer image formed on the image bearing body onto a moving transferring medium; and a control unit for controlling the image forming unit to form a predetermined image composed of a dot image with a predetermined density prior to formation of a normal image, in which a composite image is formed from the normal image and the predetermined image in an area where the normal image is to be formed, and the dot image is formed in a dot area having the normal image and the predetermined image overlapped with each other, with a density determined on the basis of a relationship between a density of the normal image and the predetermined density in the dot area.

Abstract: The invention provides a double-faced image formation system that prevents transfer and adhesion of a lubricant to an image retaining conveyer and an intermediate transfer part. The system is provided with, on a return path for reversing and conveying a sheet having toner images fixed on one side thereof, a front face electrifying unit and a rear face electrifying unit. Oil adhered on the rear face of the sheet in a fixation unit by the rear face electrifying unit is electrified to a negative polarity, and the oil adhered on the rear face is made impossible to transfer to an intermediate transfer belt. The oil adhered on the front face of the sheet in the fixation unit by the front face electrifying unit is electrified to a positive polarity, and the oil adhered on the front face is made impossible to transfer to a secondary transfer conveyance belt.

Abstract: An image forming system of an electrophotographic printer. The system includes a photosensitive body on which an electrostatic latent image is formed, a developing unit which develops the electrostatic latent image with a developer, a transfer body onto which the developed image is transferred, a first image charging unit which charges the image so as to increase an electric adhesive force of the image transferred onto the transfer body, a second image charging unit which charges the image so as to reduce the electric adhesive force of the image transferred onto the transfer body in the rear of the first image charging unit, and a transfer unit which transfers the image passing through the first and second image charging units onto paper.

Abstract: An image forming apparatus has a latent image forming portion for forming an electrostatic latent image on an image bearing member; a plurality of developing portions for developing the electrostatic latent image on the image bearing member with a developer; a primary transferring portion for transferring by sequentially superposing each developer image developed by the plurality of developing portions on an intermediate transferring member; a secondary transferring portion for collectively transferring onto a transferring material the developer images transferred by being superposed on the intermediate transferring member; and a charging portion for charging the developer images on the image bearing member; wherein the charging portion decides a charging condition in accordance with the order of transferring the developer images onto the intermediate transferring member.

Abstract: The invention describes techniques for the electrostatic printing of functional materials configured as liquid toners (45) on glass substrates (26) in a non-contact mode. The toners are patterned by a sensitized electrostatic printing plate (11) of fixed image configuration. Toner images (50) are transferred by an electric field (33) across a fluid filled mechanical gap (42) to the glass substrate (26). Techniques for optimizing the imaging and transfer processes are also disclosed. Two other techniques in which partially finished pieces are manipulated to “self-part” themselves, are described. In both cases defects in the pieces will over print the defect in the “self-healing” mode.

Abstract: An image forming apparatus includes an image carrier that rotates and carries an image on a surface of the image carrier, a latent image forming device that forms an electrostatic latent image on the image carrier, a developing device that develops the electrostatic latent image with a developer including a lubricant, and a transfer device that transfers the developed image to a transfer material. The image forming apparatus further includes a control device including a lubricant application executing device and controlling the lubricant application executing device to execute an application of the lubricant to the image carrier by actuating the developing device to apply the developer to the surface of the image carrier during one job of an image forming operation from a start of rotation of the image carrier to a stopping of the rotation of the image carrier.

Abstract: An image forming apparatus having a photoconductor for carrying a toner image; a transfer device, provided with a discharge wire, for transferring the toner image onto a transfer material through discharge in a transfer area, after a transfer material is superposed with the photoconductor; a transfer-exposure device for carrying out light exposure of a surface of the photoconductor superposed with the transfer material, in the transfer area; a separator for separating the transfer material from the photoconductor after the toner image is transferred ; and a controller for controlling the image forming apparatus. The controller controls such that light from the transfer-exposure device is applied to the photoconductor surface for the first time when the photoconductor surface superposed with the transfer material has reached the transfer area.

Abstract: A charge removing unit is provided in order to control the surface potential of an image bearing element by removing charge from a surface of the image bearing element before a toner image is transferred from the image bearing element to a transfer medium. Surface potential controlling units are provided upstream of a contact area between the image bearing element and the transfer medium in order to control the surface potential of the transfer medium so that a toner on the image bearing element does not shift to the transfer medium.

Abstract: An electrophotographic drum-shaped photoconductor has an electroconductive support and a photoconductive layer formed thereon, with a lubricating material being applied to the surface thereof in the shape of a plurality of bands spaced therebetween, constituting band-shaped lubricating material applied areas, extending along a circumference of the drum-shaped photoconductor in the direction perpendicular or substantially perpendicular to an axis of rotation of the drum-shaped photoconductor. An electrophotographic image formation method and an image forming apparatus employing the above-mentioned drum-shaped photoconductor are also disclosed.

Abstract: A perfecting press apparatus for forming images on both sides of a transfer medium. With respect to a transferring current Ipt of an image forming unit, current Ipc is made large which flows from a charge control instrument for controlling charge polarity of the toner on the transfer medium in the direction of the transfer medium. In particular, in the image forming unit causing retransfer, a de-charging light source is installed between the a developing device and a transferring device for canceling charges other than at a latent image part of an image carrier, so that the relationship between Ipt and Ipc is to be 3×Ipc≦Ipc≦6×Ipt, whereby the retransfer is suppressed to minimum for producing satisfied quality of image.

Abstract: A system and method of applying a controlled amount of fluid to a moveable image carrying member of an electrographic printing system using a liquid toner before an image is transferred to a substrate. The amount of fluid applied may be controlled by a re-wet roller, located between the toner station and the transfer station, whose distance from the moveable image carrying member is varied along with the rotational speed and direction of the re-wet roller, according to either the roughness and porosity of the substrate or the print quality of the substrate. Alternatively, the fluid may be directly applied just to image areas of the moveable image carrying member to improve print quality.

Abstract: An image forming device, including a charging unit to electrically charge a surface of an organic photoconductive medium; a light exposure unit to form an electrostatic latent image on the surface of the organic photoconductive medium; a developing unit to develop the electrostatic latent image formed with a developer; a transfer roller to transfer an image developed by the developing unit to a recording paper; a light array having a plurality of light sources arranged in a predetermined pattern; a first light path providing unit to form a light path to receive a first light portion emitted from the light sources and to allow the light to be projected on the organic photoconductive medium between the developing unit and the transfer roller; and a second light path providing unit to form a light path to receive a second portion of the light emitted from the light sources and to allow the light to be projected onto the organic photoconductive medium passing through the transfer roller, thereby removing an elect

Abstract: An image forming system of an electrophotographic printer. The system includes a photosensitive body on which an electrostatic latent image is formed, a developing unit which develops the electrostatic latent image with a developer, a transfer body onto which the developed image is transferred, a first image charging unit which charges the image so as to increase an electric adhesive force of the image transferred onto the transfer body, a second image charging unit which charges the image so as to reduce the electric adhesive force of the image transferred onto the transfer body in the rear of the first image charging unit, and a transfer unit which transfers the image passing through the first and second image charging units onto paper.

Abstract: A common polarity duplexing electrostatographic reproduction machine is provided and includes (i) a first plurality of toner image producing electrostatographic modules that each include a first image forming surface, image forming devices, and charged toner particles having a first polarity, (ii) a second plurality of toner image producing electrostatographic modules that each have a second image forming surface, image forming devices, including charged toner particles having a polarity common with the first polarity, (iii) a charged toner polarity reversing device mounted against each module of the second plurality of toner image producing electrostatographic modules for reversing a polarity of toner particles forming the second set of toner images from the first polarity to a second an opposite polarity; and (iv) a transfer device for transferring the second set of toner images having the second polarity onto a second side of the web of recording media.

Abstract: An image forming apparatus includes a developing device having a photosensitive element rotating in a given direction to form a latent electrostatic image on a surface thereof through a laser scanning unit, and a developing roller developing the latent electrostatic image into a toner image using a developer, a transfer part transferring the toner image onto a transported printing paper disposed on a paper-transporting path to engage the photosensitive element, and a subsidiary transfer part having at least one light source disposed on at least one of both sides of the paper-transporting path to expose the photosensitive element to light and thereby to enhance a transfer efficiency, and an optic fiber guide disposed longitudinally along the photosensitive element to lead the light generated from the light source to the photosensitive element. The apparatus may include an erasing part having the same structure as that of the subsidiary transfer part.

Abstract: An apparatus for digitally generating an image comprises a photoconductor assembly, a corona assembly, and a light source assembly to generate a latent image on the photoconductor. The apparatus also includes a developer assembly that includes a developer, such as powder paint, to generate an image. The apparatus may include a fuser for generating a film image. The apparatus of the present invention may include a cartridge for storing and digitally applying adhesive to the image. Furthermore, the apparatus of the present invention includes a controller for selectively controlling voltages to control thickness of the image. Additionally, apparatus may include a consumable sheet to remove excess adhesive from the substrate.

Abstract: A perfecting press apparatus for forming images on both sides of a transfer medium. With respect to a transferring current Ipt of an image forming unit, current Ipc is made large which flows from a charge control instrument for controlling charge polarity of the toner on the transfer medium in the direction of the transfer medium. In particular, in the image forming unit causing retransfer, a de-charging light source is installed between the a developing device and a transferring device for canceling charges other than at a latent image part of an image carrier, so that the relationship between Ipt and Ipc is to be 3×Ipc≦Ipc≦6×Ipt, whereby the retransfer is suppressed to minimum for producing satisfied quality of image.

Abstract: An electrophotographic drum-shaped photoconductor has an electroconductive support and a photoconductive layer formed thereon, with a lubricating material being applied to the surface thereof in the shape of a plurality of bands spaced therebetween, constituting band-shaped lubricating material applied areas, extending along a circumference of the drum-shaped photoconductor in the direction perpendicular or substantially perpendicular to an axis of rotation of the drum-shaped photoconductor. An electrophotographic image formation method and an image forming apparatus employing the above-mentioned drum-shaped photoconductor are also disclosed.

Abstract: An image forming apparatus has a latent image forming portion for forming an electrostatic latent image on an image bearing member; a plurality of developing portions for developing the electrostatic latent image on the image bearing member with a developer; a primary transferring portion for transferring by sequentially superposing each developer image developed by the plurality of developing portions on an intermediate transferring member; a secondary transferring portion for collectively transferring onto a transferring material the developer images transferred by being superposed on the intermediate transferring member; and a charging portion for charging the developer images on the image bearing member; wherein the charging portion decides a charging condition in accordance with the order of transferring the developer images onto the intermediate transferring member.

Abstract: A system and method of applying a controlled amount of fluid to a moveable image carrying member of an electrographic printing system using a liquid toner before an image is transferred to a substrate. The amount of fluid applied may be controlled by a re-wet roller, located between the toner station and the transfer station, whose distance from the moveable image carrying member is varied along with the rotational speed and direction of the re-wet roller, according to either the roughness and porosity of the substrate or the print quality of the substrate. Alternatively, the fluid may be directly applied just to image areas of the moveable image carrying member to improve print quality.

Abstract: An image forming system in an electrophotographic printer and a method for forming an image using the system. The image forming system includes a photosensitive medium on which an electrostatic latent image is formed, a developing unit for developing the electrostatic latent image with developing solution having a predetermined color, a transfer medium onto which the developed image is transferred, an image charging unit for charging the image transferred onto the transfer medium, and a transferring unit for transferring the charged image onto a paper. In the above configuration, an electric force required for the transferring step is enhanced by the image charging unit before the image on the transfer medium is transferred onto the paper, and thereby the efficiency of transferring the image onto the paper is improved more.

Abstract: An electrophotographic drum-shaped photoconductor has an electroconductive support and a photoconductive layer formed thereon, with a lubricating material being applied to the surface thereof in the shape of a plurality of bands spaced therebetween, constituting band-shaped lubricating material applied areas, extending along a circumference of the drum-shaped photoconductor in the direction perpendicular or substantially perpendicular to an axis of rotation of the drum-shaped photoconductor. An electrophotographic image formation method and an image forming apparatus employing the above-mentioned drum-shaped photoconductor are also disclosed.

Abstract: A printer or copier operates to print a carrier material on both sides. A transfer station in the printer or copier has two transfer bands which transfer toner images onto the supporting material. A transfer corotron recharges the toner particles to a polarity for transfer to the carrier material at a transfer location. A first transfer mode provides for accumulating a plurality of toner images on the transfer band before transfer to the carrier material. A second transfer mode provides continuous transfer of the toner image to the carrier material.

Abstract: An image forming apparatus includes at least one image carrier that carries an electrostatic latent image on a surface of the image carrier. At least one developing device develops the electrostatic latent image with a developer including a toner to which a first lubricant is added to form a toner image on the surface of the image carrier. A lubricant applying device applies a second lubricant onto the surface of the image carrier. A lubricant application amount adjusting device adjusts an amount of the second lubricant to be applied onto the surface of the image carrier. And, a control device controls the lubricant application amount adjusting device to adjust the amount of the second lubricant to be applied onto the surface of the image carrier according to an area of the toner image formed on the surface of the image carrier.

Abstract: A liquid electrophotographic reproduction machine including an image bearing member movable along a process path; latent image means mounted along the process path for forming a latent image electrostatically on the image bearing member; a development unit mounted along the process path and containing liquid developer material including a liquid carrier and dispersed charged toner particles for developing the latent image to form a toner image; a pre-transfer station for increasing adhesiveness of the toner image, the pre-transfer station includes an applicator member which applies a cohesion increasing (Cl) solution on the toner image; and a transfer station for transferring the toner image onto a receiving substrate.

Abstract: A liquid electrophotographic reproduction machine including an image bearing member movable along a process path; latent image means mounted along the process path for forming a latent image electrostatically on the image bearing member; a development unit mounted along the process path and containing liquid developer material including a liquid carrier and dispersed charged toner particles for developing the latent image to form a toner image; a pre-transfer station for increasing adhesiveness of the toner image, the pre-transfer station includes an applicator member which applies a cohesion increasing (Cl) solution on the toner image; and a transfer station for transferring the toner image onto a receiving substrate.

Abstract: An apparatus for efficiently transferring at least two subtractive color toner images simultaneously onto a substrate. The apparatus includes a photoreceptor, transfer charger, mechanism for placing the substrate between the photoreceptor and transfer charger, a plurality of print stations and a stabilizing charger unit. Each of the print stations include a charger unit, an exposure unit, and a developer unit for applying a respective color toner to the latent image formed by the exposure unit in conjunction with the charger unit upon the photoreceptor. Upon application to photoreceptor, each toner has an initial charge-to-mass ratio, which is subsequently increased to a saturated charge-to-mass ratio when the toner passes under the charger unit of a subsequent print station. Thus, the stabilizing charger unit substantially conforms the charge-to-mass ratio of the toner deposited by the last print station to the charge-to-mass ratio of the toner developed previously.

Abstract: In cases where equivalent air thicknesses topc (&mgr;m) and yt (&mgr;m) of the photosensitive layer and toner layer, respectively, an amount of charge per unit area (qpm (mg/cm2)−1) of the toner layer, normalized based on an amount of charge per unit area &rgr;opc in a non-image portion of the photosensitive layer, an amount of charge per unit area &rgr;′opc in the non-image portion of the photosensitive layer upon entrance into a transfer region, and a total amount of charge per unit area &rgr;o of the toner layer are set so as to satisfy the following equation, then, variance of electric field hardly occurs in the transfer region: |(&rgr;′opc−&rgr;o)/(&rgr;opc−&rgr;o)|<1 where &rgr;o=qpm{(−0.01·topc+0.145)yt2+(0.001·topc+0.937)yt}.

Abstract: An imaging apparatus comprising a support member including a support surface for supporting a layer of marking material; a marking material supply apparatus for depositing marking material on the surface of said support member to form a layer of marking material thereon; a charging source for selectively delivering charge species to the layer of marking material in an imagewise manner to form an electrostatic latent image in the layer of marking material, wherein the electrostatic latent image includes image areas with a first charge voltage and nonimage areas with a second charge voltage distinguishable from the: first charge voltage; and a separator member for selectively separating portions of the marking material layer in accordance with the latent image in the marking material layer to create a developed image and wherein said marking material is comprised of a liquid developer comprised of a nonpolar liquid, resin, colorant, and a charge acceptance component comprised of a aluminum complex.

Abstract: The present invention provides an image forming apparatus which has an image bearing member developing device for developing an electrostatic latent image formed on the image bearing member with developer, cleaning device for removing residual developer on the image bearing member by contacting with the image bearing member at a cleaning position, charging applying device for applying charge of polarity opposite to normal charging polarity of the developer to the developer before the developer applied to the image bearing member is carried to the cleaning position, wherein a developer image formed on the image bearing member by the developing device is transferred onto a transfer material and wherein the developing device applies developer to an area of the image bearing member which is not contacted with the transfer material, and the developer is carried to the cleaning position by the image bearing member.

Abstract: An image forming apparatus of the type sequentially forming toner images of different colors on an image carrier while sequentially transferring them to an intermediate transfer body one above the other, and then transferring the resulting composite toner image from the intermediate transfer body to a paper or similar recording medium. Dot toner images different from desired toner images are formed on the image carrier. The dot toner images are transferred from the image carrier to the intermediate transfer body and then to the recording medium. The individual toner images are transferred from the image carrier to the intermediate transfer body in accurate register with each other.

Abstract: A development section uses a liquid toner as a liquid developer and forms a toner image according to an electric field established between the development section and a photosensitive drum. The toner image is transferred from the photosensitive drum onto an intermediate transfer roller 15 according to an electric field established between the same and the photosensitive drum. The toner image is further transferred from the intermediate transfer roller to an intermediate transfer belt 16 and then transferred to a transfer-and-fixation section, which melt-transfers the toner image onto a printing medium. Photosensitive drums 11-14 are provided so as to correspond to a plurality of colors. Toner images formed on the corresponding photosensitive drums are sequentially transferred and superposed on the intermediate transfer roller.

Abstract: Method and apparatus for eliminating stray background toner in electrostatic printer images by first electrostatically neutralizing any background toner charge and then removing neutralized toner. An ac corona wire positioned between a developer unit and a background toner scavenger is employed to neutralize unwanted background toner. Alternately, a high current density ac discharge between two electrodes separated by a dielectric layer may be employed as a bipolar ion source. Toner may be scavenged using either a vacuum suction manifold and/or a rotating brush.

Abstract: An apparatus for developing a latent electrostatic image on a charge retentive surface moving in a process direction with toner, the apparatus comprising: a supply of toner; a donor structure spaced from the charge retentive surface for conveying toner from the supply of toner to an area adjacent the charge retentive surface, a device for applying an alternating current directly to the donor structure to create an alternating electrostatic field between the donor structure and said charge retentive surface to produce a toner cloud adjacent the charge retentive surface for developing the latent electrostatic image thereon; and an edge enhancement device, adjacent to the donor structure, for redistributing toner on the developed latent electrostatic image.

Abstract: An electrophotographic apparatus includes a decreasing device for decreasing the potential difference between the potential of the toner-adhering portion of the photosensitive body and the potential of the toner-nonadhering portion of the photosensitive body after the development by a developing device and before the transfer by a transferring device. The potential of the toner-nonadhering portion is maintained higher than the potential of the toner-adhering portion regardless of a decrease of the potential difference.

Abstract: An electrophotographic printer includes a photosensitive drum, a developing unit, an image transfer unit, and pre-transfer discharges arranged between the developing unit and the image transfer unit. The pre-transfer discharging means is arranged to progressively reduce the absolute value of the electric potential of a given point in the surface of the photosensitive drum. The reduction of the electric potential is performed in a non-abrupt manner through two or more steps as the given point is moved from the developing unit to the image transfer unit.