Abstract: A cleaning blade for a photosensitive member carrying a liquid developer includes a free end surface provided at one end portion in a height direction of the blade, the free end surface being provided with an edge portion at one end portion of the free end surface with respect to the thickness direction. The edge portion has curved portions and a linear portion therebetween. As seen in the thickness direction, the curved portion includes an arcuate shape portion and is connected with the linear portion such that the linear portion is tangential of the arcuate shape; a height of the blade increases toward the end portion of the blade; a maximum angle formed between the curved portion and the linear portion is not less than 5 degrees; and the curved portion includes a portion having radius of curvature not less than 240 mm and not more than 320 mm.

Abstract: Cleaning a photoconductive surface (16) from particles and excess fluid with at least two wiper blades, wherein a first wiper blade (12) is to contact the photoconductive surface (16) and to wipe at least some of the particles and at least some of the excess fluid from the photoconductive surface (16) and wherein a second wiper blade (14) is to contact the photoconductive surface (16) and to wipe at least some of the particles and at least some of the excess fluid that have passed the first wiper blade, from the photoconductive surface (16).

Abstract: Techniques for liquid electrography printing are described herein. In at least some examples herein, a liquid electrographic printer includes a charging element for charging a photo imaging plate (PIP). A light source irradiates light onto the charge element. The irradiated light is to heat the charge element to a selected temperature.

Abstract: Disclosed herein are methods of providing location-based information with respect to a topological map. A method may include (a) receiving a query for location-related information, (b) optionally generating data representing the topological map, (c) accessing the location-related information in a map-to-scale, (d) optionally determining an association between one or more points (or links) in the map-to-scale and one or more corresponding points (or links) in a topological map, (e) identifying one or more points (or links) in the map-to-scale that relate to the location-related information and that correspond to one or more points (or links) in the topological map, (f) optionally determining a relative position of the location-related information with respect to the identified one or more map-to-scale points (or links), and (g) displaying the location-related information with respect to the corresponding one or more points (or links) in the topological map.

Abstract: A digital printing system includes a development member in rotational contact with a further member for imagewise transferring liquid toner from the development member optionally via the further member to a substrate. The system is such that toner residue remains on the development member after the transfer. A treatment device is present for patternwise treatment of the toner residue on the development member, especially by addition of a dispersing agent to facilitate removal of the toner residue. A controller is present for controlling the patternwise treatment. A system is used for robust and continuous printing and is suitable for recycling of the toner residue into liquid toner.

Abstract: An image forming apparatus includes a toner container, a mounting portion, an elastic member, a displacement amount detection portion, a stored amount determination portion, and a cushioning member. The elastic member is configured to support the toner container by an elastic force thereof and contract and stretch in accordance with a weight of the toner container. The displacement amount detection portion is configured to detect a displacement amount of the toner container displaced in a gravitational direction when the weight of the toner container increases. The stored amount determination portion is configured to determine an amount of the toner stored in the toner container on the basis of a result of detection by the displacement amount detection portion. The cushioning member is configured to cushion vibration of the toner container in the gravitational direction which vibration occurs due to a change in the weight of the toner container.

Abstract: In an LEP printer having a wiper blade for wiping a photo imaging plate, the photo imaging plate may include a PIP foil with a trailing edge having a zone of a roughening pattern which includes notches that are inclined with respect to a contact line of the wiper blade. The zone of roughening pattern is confined between two opposite margins lacking any roughening.

Abstract: An image forming apparatus has a control unit configured to: after an image is formed in a color mode, if an integrated supply amount is larger than or equal to a reference supply amount, cause a supply image with a first amount of developer, otherwise, cause a supply image with a second amount of developer larger that the first amount; and, after an image is formed in the monochrome mode, cause a supply image with a third amount of developer smaller than the first amount, and, to make an interval between recording materials when the supply image with the third amount is formed shorter than an interval between recording materials when the supply image with the first amount or larger is formed.

Abstract: Vortex flow resisters (20, 220) deliver liquid from an upper chamber (16, 216) to a lower chamber (18, 218) prior to the liquid being distributed onto a cylinder (12, 14, 212, 122).

Abstract: A carrier removing apparatus, including: an electrode, having a plurality of openings through which a carrier passes, disposed to oppose an image carrier, and a power source to apply a voltage onto the electrode so as to separate the carrier on the image carrier from the image carrier, wherein the electrode has a surface along a surface of the image carrier.

Abstract: A digital printing method using liquid toner, the method comprising transporting liquid toner comprising charged, caked and compacted imaging particles on a first member (101) in a transport direction of said first member; wherein the method further comprises loosening compacted and caked imaging particles by rubbing using a rubbing portion that is being pressed against the first member and that at least partially contains or absorbs the liquid toner while being pressed against the first member; and scraping off loosened and decaked imaging particles using a scraper downstream of an area of contact between the first member and the rubbing portion.

Abstract: A method of maintaining a photoconductive member of an image forming apparatus is disclosed. The method includes applying fluid to a photoconductive member to form an image thereon, transferring the fluid from the photoconductive member in the form of the image and providing sponge applicator fluid to respective sponge applicator units. The method also includes squeezing the sponge applicator units to remove at least a portion of the sponge applicator fluid therefrom and sequentially placing each one of the sponge applicator units in contact with the photoconductive member to cool and clean the photoconductive member.

Abstract: A developing apparatus includes: a developer accumulation portion; a developer drawing-up portion that draws up the liquid developer accumulated in the developer accumulation portion; a developing roller that supplies the liquid developer to the image supporting body in a region facing the image supporting body; a developer removing portion that is disposed to contact a predetermined position on a surface of the developing roller on a downstream side to the region facing the image supporting body in a rotational direction of the developing roller, and removes the liquid developer remaining on the surface of the developing roller; and an accumulated developer delivery portion that delivers the liquid developer accumulated in the developer accumulation portion to a predetermined region on the surface of the developing roller between the region facing the image supporting body and the predetermined position contacting the developer removing portion.

Abstract: In a transfer unit, a rotating transfer element is arranged adjacent a charge image carrier that takes toner images from the charge image carrier and supplies the images to a transfer printing station. A scoop element applies carrier fluid to the transfer element. A friction element is provided after the scoop element adjacent to the transfer element at such a distance from the transfer element that a gap between the transfer element and the friction element is substantially completely filled with the carrier fluid, the friction element and the transfer element rotating with different speeds. Residual toner remaining on the transfer element after the transfer printing is loosened by friction forces.

Abstract: An image forming apparatus includes: a latent image bearing member on which a latent image is formed; a developing unit that develops the latent image using a liquid developer; a transfer member onto which the image is transferred; a cleaning unit that cleans the latent image bearing member; a cleaning roller, to which a bias is applied, that cleans the transfer member by making contact with the transfer member; a blade that cleans the cleaning roller by making contact with the cleaning roller; a cleaning blade that cleans the transfer member cleaned by the cleaning roller by making contact with the transfer member; a holding unit that holds collected material scratched by the blade and the cleaning blade; an application unit that applies the collected material to the cleaning roller; and a transport channel that transports the collected material collected by the cleaning unit to the holding unit.

Abstract: An image forming apparatus of the invention includes a carrier solution application roller that rotates centering on a rotary shaft and applies a carrier solution to a transfer roller after an image of a liquid developer including toner and the carrier solution is transferred to a transfer medium, a transfer roller cleaning roller, supported by a cleaning member support portion through a rotary shaft, which removes toner remaining in the transfer roller, and a carrier solution application roller of which the amount of movement is larger than the amount of movement of the transfer roller cleaning roller when the cleaning member support portion is rotated. Even when the transfer roller moves, satisfactory cleaning properties are secured without breaking a mutual positional relationship by facilitating mutual positioning between the transfer roller and the transfer roller cleaning roller.

Abstract: A developing roller which comes into contact with a latent image carrier drum on a first side with respect to an imaginary vertical plane passing through the rotation center of the latent image carrier drum, thereby developing a latent image which is carried on the latent image carrier drum by a liquid developer that includes toner and carrier liquid is provided, and a squeeze roller which comes into contact with the latent image carrier drum developed by the developing roller on a second side on the opposite side to the first side with respect to the imaginary vertical plane further on the upper side in the vertical direction than an imaginary horizontal plane passing through the rotation center of the latent image carrier drum and perpendicular to the imaginary vertical plane, thereby squeezing an image developed to the latent image carrier drum is provided.

Abstract: A cleaning device includes a cleaning roller which contacts an intermediate transfer belt for carrying an image developed using a liquid developer, a cleaning roller which contacts the other cleaning roller and has a greater axial length than the other cleaning roller, and a rubber blade which contacts the cleaning roller and has a greater axial length than the cleaning roller.

Abstract: The purpose of the present invention is to provide a method for transferring a pattern of a circuit pattern precursor formed of electroconductive particles containing no resin component onto an objective substrate with high transfer efficiency while retaining a pattern shape. A method of transferring the circuit pattern precursor formed from an conductive particle dispersed solution on a dielectric thin film body includes the steps of: temporarily removing a liquid film remaining around the circuit pattern precursor right after a development step; subsequently re-electrifying the electroconductive particle pattern by supplying a solvent again to the circuit pattern precursor; and then electrostatically transferring the pattern onto the objective substrate through electrophoresis in the solvent.

Abstract: A transfer device includes: a transfer belt hung around a roller; and a transfer belt sealing member in contact with a transfer surface and a circumferential end surface of the transfer belt and in contact with the circumferential end surface of the transfer belt diagonally relative to a thickness direction of the transfer belt.

Abstract: An image forming apparatus includes: a latent image bearing member on which a latent image is formed; a developing unit that develops the latent image using a liquid developer; a transfer member onto which the image is transferred; a cleaning unit that cleans the latent image bearing member; a cleaning roller, to which a bias is applied, that cleans the transfer member by making contact with the transfer member; a blade that cleans the cleaning roller by making contact with the cleaning roller; a cleaning blade that cleans the transfer member cleaned by the cleaning roller by making contact with the transfer member; a holding unit that holds collected material scratched by the blade and the cleaning blade; an application unit that applies the collected material to the cleaning roller; and a transport channel that transports the collected material collected by the cleaning unit to the holding unit.

Abstract: A transfer apparatus comprises a toner image supporting body and a corona transfer means, which are oppositely disposed, and a vibrating unit for exerting vibration force to the rear face of a toner supporting body, disposed opposite to the corona transfer means, wherein the vibrating unit has a cantilever structure for holding an end of a piezoelectric bimorph element in which a pair of piezoelectric bodies each having an electrode, are bonded to both sides of a conductive elastic member (a shim member). A protrusion portion is provided on the other end of the piezoelectric bimorph element.

Abstract: To provide a cleaning apparatus capable of maintaining high cleaning performance even if surface roughness of an image carrier is increased due to wear and a wet image forming apparatus installing the concerned cleaning apparatus, thereby enabling to form images of a stable quality. The cleaning apparatus for removing liquid developer remaining on the surface of a latent image carrier and an intermediate transfer member, which are an image carrier of the image forming apparatus for forming images with the liquid developer including toner particles and carrier liquid, includes three stages of cleaning sections such as a preliminary cleaning member for making contact with the image carrier and suspending the toner particles adhered to the surface of the image carrier in the carrier liquid, a toner particles removing member for removing the suspended toner particles by electrostatic force, and a carrier liquid removing member for removing the remaining carrier liquid.

Abstract: A developing system comprises: a plurality of image carriers; a plurality of developing devices for developing electrostatic latent images, formed on the plurality of image carriers, with respective liquid developers of different colors of which carrier is nonvolatile solvent; and developer collecting means which are disposed at a plurality of locations for collecting excess developers, wherein the developing devices have developer containers, respectively. The developing system further comprises a carrier storing tank for distributing the carrier to the respective developer containers.

Abstract: An image forming apparatus includes an intermediate transfer belt that has an elastic layer to which a toner image on an image carrier developed using a liquid developer is primarily transferred, a cleaning roller that cleans an extraneous material remaining on the intermediate transfer belt after secondary transfer, and a coating member that coats the intermediate transfer belt with a cleaning liquid.

Abstract: An image forming device includes a development section provided with a developer carrier adapted to perform development using a liquid developer including a carrier liquid and toner particles, an image carrier adapted to carry an image developed by the development section, an cleaning roller of the image carrier having contact with the image carrier, an cleaning blade of the cleaning roller of the image carrier having contact with the cleaning roller of the image carrier at one of a position on an imaginary line of an intersection between an imaginary plane passing through a center of a rotational axis of the cleaning roller of the image carrier and perpendicular to an imaginary vertical plane and a surface of the cleaning roller of the image carrier and a position lower than the imaginary line in a vertical direction, and an image carrier recovery reservoir adapted to store the liquid developer recovered by the cleaning blade of the cleaning roller of the image carrier.

Abstract: A system for recycling a liquid in a printer comprises a first reservoir configured for collecting possibly polluted liquid to be recycled from the printer, a filtration system configured for purifying the liquid received from the first reservoir, and a second reservoir configured for collecting the liquid from the filtration system, wherein overflow from the second reservoir is directed to the first reservoir.

Abstract: An image forming device includes a developer carrier for carrying a liquid developer, a latent image carrier to which a latent image is developed by the developer carrier, a charging member for charging the latent image carrier, an exposure device for exposing the latent image carrier, a latent image carrier cleaning roller for applying a bias to clean the latent image carrier, a latent image carrier cleaning blade having contact with the latent image carrier and for scraping out the developer on the latent image carrier, and a cleaning process control section for cleaning the latent image carrier in a condition in which a charging bias of the charging member is applied, the developer carrier has contact with the latent image carrier, and the bias of the latent image carrier cleaning roller is applied to the latent image carrier cleaning roller.

Abstract: A cleaning unit includes a traveling belt and a belt cleaning member. The traveling belt is formed in a loop and travels via the vicinity of the contact point between an image support member and an image support member cleaning member, and comes into contact with liquid developer stored in the cleaning unit. The belt cleaning member is in contact with the traveling belt and arranged in a position downstream of the contact point between the traveling belt and liquid developer stored in the cleaning unit, and upstream of the point at which the traveling belt passes the vicinity of the contact point between the image support member and the image support member cleaning member in the traveling direction of the traveling belt. The belt cleaning member is configured to remove liquid developer attached to the traveling belt.

Abstract: An electrically conductive pattern forming apparatus has process disposition which reduces contamination of a pattern or inside of the apparatus due to backflow and leakage of a liquid material such as a developing agent or a cleaning liquid. A developing device and a cleaning device in the electrically conductive pattern forming apparatus using an electrophotographic method are disposed in a lower region about the center of a photoreceptor, a solvent removing process is disposed in a region in which the photoreceptor rotates upward, and a transfer liquid applying process and an electrostatic transfer process are disposed above the center of the photoreceptor and in a region in which the photoreceptor rotates downward.

Abstract: A used developer cleaning system is provided which removes used developer remaining on an image transmission medium after a developer image has been transferred, and an image forming apparatus having such a used developer cleaning system. The used developer cleaning system includes a cleaning section, a used developer collecting section, a first sludge filtering section, positioned in the used developer collecting section to divide the used developer collecting section into at least two spaces, and a used developer storage section for storing the used developer, from which sludge has been filtered through the first sludge filtering section. The used developer storage section communicates with the used developer collecting section.

Abstract: To provide a cleaning apparatus capable of maintaining high cleaning performance even if surface roughness of an image carrier is increased due to wear and a wet image forming apparatus installing the concerned cleaning apparatus, thereby enabling to form images of a stable quality. The cleaning apparatus for removing liquid developer remaining on the surface of a latent image carrier and an intermediate transfer member, which are an image carrier of the image forming apparatus for forming images with the liquid developer including toner particles and carrier liquid, includes three stages of cleaning sections such as a preliminary cleaning member for making contact with the image carrier and suspending the toner particles adhered to the surface of the image carrier in the carrier liquid, a toner particles removing member for removing the suspended toner particles by electrostatic force, and a carrier liquid removing member for removing the remaining carrier liquid.

Abstract: A wet electrophotographic apparatus includes an intermediate transcriptional unit that includes a rubber member on a surface thereof, the intermediate transcriptional unit being configured to transcribe a toner image formed by toner held on a surface of the rubber member onto a printed subject, a cleaning solution applying unit configured to apply cleaning solution to the surface of the rubber member after transcribing the toner image onto the printed subject, and a toner removing unit configured to have a higher stiffness than that of the rubber member and to be in contact with the rubber member under a predetermined pressure so as to remove residual toner, which is left on the intermediate transcriptional unit even after transcribing the toner image onto the printed subject, with the cleaning solution.

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: An apparatus and method for cleaning an image transfer surface in an image transfer device. The cleaning apparatus includes a first cleaning station and a second cleaning station positioned to consecutively clean the image transfer surface. The first and second cleaning stations apply cleaning fluid to the image transfer surface and remove cleaning fluid with residual material from the image transfer surface. A first tank supplies cleaning fluid to, and receives cleaning fluid with residual material from, the first cleaning station. A second tank supplies cleaning fluid to, and receives cleaning fluid with residual material from, the second cleaning station. The second tank also supplies cleaning fluid to the first tank.

Abstract: A cleaning apparatus for a liquid-development electrophotographic apparatus in which, after a toner image formed on a surface of an intermediate transfer member by use of a liquid developer is transferred to a printing medium, the liquid developer remaining on the intermediate transfer is removed and collected. The cleaning apparatus includes a cleaning-liquid application device for applying a cleaning liquid to the intermediate transfer member which has transferred an image to the printing medium; a bias voltage application device for applying a bias voltage opposite in polarity to charged toner particles of the developer to the intermediate transfer member; and a collection device for removing the cleaning liquid which has been applied to and the residual developer which remains on the intermediate transfer member from the intermediate transfer member without transfer of an image to the printing medium, and collecting the removed cleaning liquid and residual developer.

Abstract: A liquid image forming apparatus includes a waste developing agent container in which a developing agent removed by the cleaning blade from a photosensitive body is stored. The waste developing agent container is provided in a developing container.

Abstract: A device for cleaning an image carrier of residuals of an ink image, in which for inking the latent image on a latent image carrier, droplets are transferred from a liquid layer onto the surface of the latent image carrier by overcoming an air gap. The cleaning device is arranged at the circumference of the image carrier and removing the residual ink remaining after transfer of the image inked with a liquid ink is removed from the surface of the image carrier.

Abstract: After passing a position of transfer to a printing medium 10, a portion of an intermediate transfer member 1 on which an image is previously formed reaches the position of a cleaning unit 2. The cleaning unit 2 removes residual toner, whereby the intermediate transfer member 1 prepares for a next cycle of formation of images in the corresponding colors by means of the developing units 4, 5, 6, and 7. The cleaning unit 2 includes an application friction roller 21 and a bias roller 24. The application friction roller 21 has a function to weaken cohesion/firm adhesion of residual toner through application of a cleaning liquid to the intermediate transfer member 1 and a function to exfoliate and disperse the residual toner in the cleaning liquid through imposition of a shear force on the residual toner. The bias roller 24 includes a bias voltage generation mechanism 24a for applying a bias voltage between the bias roller 24 and the intermediate transfer member 1.

Abstract: A liquid electrophotographic imaging apparatus contains at least one drying sheet for removing excess carrier liquid in a liquid toner toned latent image on a photoconductor surface. The drying sheet comprises a flexible substrate having a first surface and second surface; at least one oleophilic carrier liquid absorptive layer on the first surface of the flexible substrate; and the first surface of the flexible substrate facing said photoconductor surface, latent image or liquid toned latent image.

Abstract: A cleaning method for cleaning a developer container includes a step of blowing air through an opening formed in the developer container at a first flow rate; a step of sucking air through the opening at a second flow rate which is larger than the first flow rate; wherein while the blowing and suction steps are being simultaneously carried out, ambient air is permitted to enter the developer container through an ambient air inlet.

Abstract: A liquid-development electrophotographic apparatus utilizes a nonvolatile, high-viscosity, high-concentration liquid toner as a liquid developer. A developing section is in contact with photosensitive drums 11-14, on which an electrostatic latent image is formed, so that the liquid developer is supplied onto photosensitive drums 11-14. Toner particles contained in the liquid developer adhere to the photosensitive drums 11-14 according to an electric field established between the developing section and the photosensitive drums 11-14 to form toner images. The toner images are transferred from the photosensitive drums 11-14 to an intermediate transfer section. A transfer-and-fixation section includes a heater to melt-transfer the toner images onto the printing medium. A development section is disposed at a lower portion of the apparatus to prevent smudging of the printing medium and the intermediate transfer section even when the liquid toner spills.

Abstract: A liquid image forming apparatus includes a waste developing agent container in which a developing agent removed by the cleaning blade from a photosensitive body is stored. The waste developing agent container is provided in a developing container.

Abstract: An excess toner removal area is made broader over the whole area with respect to a developer applied area that is broader than an image effective area. Thereby a liquid developer, that tends to spread slightly broader than the applied area after being applied to a photoreceptor drum, is removed by a sweep roller that can sweep excess toner present in an area broader than the original applied area and an excess toner remaining area is then prevented from being formed on the photoreceptor drum. Accordingly, the excess toner on the latent image carrier is removed as much as possible, and a transfer medium and peripheral members are prevented from being soiled due to residual excess toner.

Abstract: A device for cleaning an image carrier of residuals of an ink image, in which for inking the latent image on a latent image carrier, droplets are transferred from a liquid layer onto the surface of the latent image carrier by overcoming an air gap. The cleaning device is arranged at the circumference of the image carrier and removing the residual ink remaining after transfer of the image inked with a liquid ink is removed from the surface of the image carrier.

Abstract: A photosensitive drum cleaning device of a wet type printer includes: a cleaning blade disposed on a photosensitive drum to contact and wipe an outer circumference of the rotating photosensitive drum, for removing a developer that has not been transferred to a transfer belt but remains on the photosensitive drum; and a developer drain holder for collecting and discharging the developer removed by the cleaning blade. The cleaning blade includes first and second guide wings which are respectively formed at opposite sides of a contact portion of the cleaning blade and the photosensitive drum and which have a predetermined height. The guide wings prevent the developer that is wiped by the cleaning blade from streaming down over the opposite sides of the cleaning blade. The guide wings are formed integrally with the cleaning blade to have a width that is thinner than the thickness of the cleaning blade.

Abstract: A toner cleaning system for cleaning a toner from a supporting surface, including a movable member having a carrier permeable segment that features a porous structure. The movable member is actuated to engage the supporting surface so as to receive therefrom the toner at an exterior surface of the carrier permeable segment. A quantity of carrier fluid is provided at an interior surface of the carrier permeable segment. The carrier permeable segment supports carrier fluid flow from the interior surface to a portion of the received toner so as to disengage the portion of the received toner from the carrier permeable segment. The disengaged toner portion is then susceptible to collection and re-use.

Abstract: A printing apparatus for printing an image onto a print medium with use of a liquid developer which contains a liquid carrier and a toner being dispersed in the liquid carrier. The printing apparatus has: an image holding member having an imaging surface on which a latent image corresponding to the image to be printed is generated; a development unit which provides the liquid developer to the imaging surface to form a toner image corresponding to the latent image; a transfer member which transfers the toner image from the imaging surface to the print medium; and a fibrous wipe member having a cleaning face contacting with the imaging surface for wiping a residual toner failing to be transferred from the imaging surface by moving relatively to the imaging surface in a first direction. A cleaning liquid is impregnated at a ratio of 2 grams per square meter to 200 grams per square meter in the fibrous wipe member.

Abstract: The present invention provides a liquid carrier removing system which efficiently removes liquid carrier from a liquid developed image on a latent image bearing member, and reduces disturbance of a visible image formed with toner particles. The liquid carrier of the liquid developed image on the latent image bearing member is sucked by an absorbing cylinder, the surface of which is formed by a porous layer and pressed to the bearing member. A vacuum system is coupled to the absorbing cylinder to make the inside of the cylinder be negative pressure. The liquid carrier taken in the absorbing cylinder is sucked and collected inside the cylinder. In order that the pressed region of the absorbing cylinder may not be subjected to the sucking action by the negative pressure, a shield, which covers a part of the inside wall of the absorbing cylinder, is provided. Sucking and removing the liquid carrier of the liquid developed image and collection of the sucked liquid carrier are carried out separately.

Abstract: A developing device of the type using a developing liquid and applicable to an image forming apparatus includes a developing roller and a sweep roller. The developing roller is pressed against a photoconductive drum to thereby form a nip. The sweep roller is positioned downstream of the nip in the direction of rotation of the drum and pressed against the drum in such a manner as to sandwich a developed toner layer. The surface of the sweep roller moves at substantially the same speed as the surface of the drum. A bias voltage (250 V) close to the surface potential (100 V to 200 V) of the toner layer formed on the drum is applied to the sweep roller. The bias causes the sweep roller to attract stray excess toner present on the background of the drum after development, thereby preventing a toner image from being blurred.