Abstract: Provided is an image forming apparatus including: a latent image carrier; a charging unit; a latent image forming unit; a developing unit; a transferring unit; and a cleaning unit, wherein a voltage of the non-image portion of the latent image carrier is Vo, a voltage of the developing bias at the time when a force generated to bias the toner charged with the regular charging polarity in a direction from the latent image carrier to the toner carrier is maximum is Vmax, and a voltage of the developing bias at the time when a force generated to bias the toner charged with the regular charging polarity in a direction from the toner carrier to the latent image carrier is maximum is Vmin, in the developing position, an equation |Vmax?Vo|>|Vmin?Vo| is satisfied.

Abstract: Provided is an image forming apparatus including: a latent image carrier; a charging unit; a latent image forming unit; a developing unit; a transferring unit; and a control unit that performs an image forming process by controlling the latent image carrier, the charging unit, the latent image forming unit, the developing unit and the transferring unit, wherein, during execution of the image forming process, the latent image carrier circulates by passing through the charging position, the developing position and the transferring position in a state in which at least one of toner, which is charged with a polarity opposite to the regular charging polarity, and external additive agent, which is separated from the toner and charged with a polarity opposite to the regular charging polarity, is distributed and adhered to the surface of the latent image carrier.

Abstract: Provided is an image forming apparatus including: a latent image carrier; a charging unit; a latent image forming unit; a developing unit that has a toner carrier; a transferring unit that transfers the toner image on the transfer medium; and a cleaning unit that removes a toner that remains to be adhered to the latent image carrier, wherein the toner carrier carries a toner layer including a contact toner that is directly in contact with the surface of the toner carrier and a non-contact toner that is not directly in contact with the surface of the toner carrier on the surface thereof, and wherein a voltage of the transferring bias is a DC voltage that does not generate discharge between the image portion of the latent image carrier and the transfer medium but generate discharge between the non-image portion of the latent image carrier and the transfer medium.

Abstract: An image carrier cleaning device includes: a first charging member which charges an image carrier to the same polarity as that of a toner after a transfer operation of a toner image formed by the toner charged to a predetermined polarity and having an external additive added thereto; a cleaning member which comes into contact with the image carrier charged by the first charging member; and a second charging member which applies an electric charge having a polarity opposite to a polarity of the toner to the image carrier having passed through the cleaning member.

Abstract: An image forming apparatus includes: a latent image carrier which circumferentially rotates in a predetermined rotational direction; a lubricant applying unit which applies a lubricant on a surface of the latent image carrier in a predetermined application position; a developing unit which adheres a toner including an additive having an abrasion effect onto the surface of the latent image carrier on which the lubricant is coated to form a toner image, in a development position located on a downstream side of the application position in the rotational direction; and a conductive blade which cleans and removes the toner on the surface of the latent image carrier in contact with the surface of the latent image carrier, and charges the surface of the latent image carrier, in a cleaning and charging position located on an upstream side of the development position in the rotational direction.

Abstract: Provided is an image forming apparatus including: a latent image carrier; a lubricant applying unit configured to bring a conductive contact member into contact with a surface of the latent image carrier; a development unit configured to attach toner to the surface of the latent image carrier; and a conductive blade brought into contact with the surface of the latent image carrier at a cleaning position, wherein a bias is applied to at least one of the conductive contact member and the conductive blade such that the surface of the latent image carrier is electrified, and wherein, as the durability of the conductive blade is prolonged, a ratio of the electrification of the surface of the latent image carrier by the conductive blade and the electrification of the surface of the latent image carrier by the conductive contact member is changed.

Abstract: An image forming apparatus includes: a latent image carrier which circumferentially rotates in a predetermined rotational direction; a conductive blade which cleans a surface of the latent image carrier by being in contact with the surface of the latent image carrier, and charges the surface of the latent image carrier at a first electric potential having the same polarity as normal charged polarity of a toner according to application of direct current voltage having the same polarity as the normal charged polarity of the toner, in a predetermined cleaning and charging position; and a charger which provides electric charge having reverse polarity to the normal charged polarity and adjusts an electric potential of the surface of the latent image carrier to a second electric potential, in a secondary charging position located on a downstream side of the cleaning and charging position in the rotational direction.

Abstract: A development device includes a housing having toner housed therein; a toner carrying roller that has a plurality of convex portions and concave portions surrounding the convex portions, formed on a surface thereof; and a conductive restriction blade in which a free end or an adjoining region adjacent to the free end abuts the surface of the toner carrying roller, thereby restricting the amount of the toner carried on surface of the toner carrying roller, wherein the toner has an external additive including a metal oxide, the restriction blade is applied with a restriction bias voltage of the same polarity as the regular electrification polarity of the toner, and a gap between the front end of the free end and the convex portion of the toner carrying roller is smaller than a volume average particle diameter of the toner.

Abstract: A developing device, an image forming apparatus and an image forming method are disclosed. The developing device includes a housing that stores toner therein; a toner carrying roller that has a plurality of convex portions and concave portions surrounding the convex portions are formed on the surface of the toner carrying roller; and a conductive regulation blade having a free end comes in contact with the surface of the toner carrying roller. The toner includes a conductive external additive as an external additive. The toner carrying roller carries both contact toner which is in direct contact with the surface of the toner carrying roller and non-contact toner which is not in direct contact with the surface of the toner carrying roller, on the concave portion. The regulation blade is applied with a regulation bias voltage of the same polarity as a normal charge polarity of the toner.

Abstract: Provided is an image forming apparatus including: a latent image carrier; a charging unit; a latent image forming unit; a developing unit that has a toner carrier; a transferring unit that transfers the toner image on the transfer medium; and a cleaning unit that removes a toner that remains to be adhered to the latent image carrier, wherein the toner carrier carries a toner layer including a contact toner that is directly in contact with the surface of the toner carrier and a non-contact toner that is not directly in contact with the surface of the toner carrier on the surface thereof, and wherein a voltage of the transferring bias is a DC voltage that does not generate discharge between the image portion of the latent image carrier and the transfer medium but generate discharge between the non-image portion of the latent image carrier and the transfer medium.

Abstract: Provided is an image forming apparatus including: a latent image carrier; a charging unit; a latent image forming unit; a developing unit; a transferring unit; and a control unit that performs an image forming process by controlling the latent image carrier, the charging unit, the latent image forming unit, the developing unit and the transferring unit, wherein, during execution of the image forming process, the latent image carrier circulates by passing through the charging position, the developing position and the transferring position in a state in which at least one of toner, which is charged with a polarity opposite to the regular charging polarity, and external additive agent, which is separated from the toner and charged with a polarity opposite to the regular charging polarity, is distributed and adhered to the surface of the latent image carrier.

Abstract: Provided is an image forming apparatus including: a latent image carrier; a charging unit; a latent image forming unit; a developing unit; a transferring unit; and a cleaning unit, wherein a voltage of the non-image portion of the latent image carrier is Vo, a voltage of the developing bias at the time when a force generated to bias the toner charged with the regular charging polarity in a direction from the latent image carrier to the toner carrier is maximum is Vmax, and a voltage of the developing bias at the time when a force generated to bias the toner charged with the regular charging polarity in a direction from the toner carrier to the latent image carrier is maximum is Vmin, in the developing position, an equation |Vmax?Vo|>|Vmin?Vo| is satisfied.

Abstract: A CPU 113 executes a control program stored in a memory 116 thereby forming a plurality of patch images with a developing bias increased for each of the patch images; detecting a density of each of the patch images by means of a patch sensor 17; and comparing the image densities to determine whether the image density is saturated or not. Then, an image forming condition in which an image density is substantially saturated is determined and is stored in the memory 116. When a print command signal is inputted from an external device via a main controller 100, a printing operation is performed under the image forming condition stored in the memory 116.

Abstract: An image carrier cleaning device includes: a first charging member which charges an image carrier to the same polarity as that of a toner after a transfer operation of a toner image formed by the toner charged to a predetermined polarity and having an external additive added thereto; a cleaning member which comes into contact with the image carrier charged by the first charging member; and a second charging member which applies an electric charge having a polarity opposite to a polarity of the toner to the image carrier having passed through the cleaning member.

Abstract: A charging roller, adapted to face an image carrier at a predetermined charging gap and charge the image carrier in a non-contact state, including: a conductive shaft, provided with a pair of annular concave portions formed on an outer circumferential surface at both ends thereof; a conductive layer, formed on the outer circumference surface at a center portion of the conductive shaft defined between the pair of concave portions; and an insulating layer, formed on the outer circumferential surface at outer portions of the conductive shaft from the pair of annular concave portions.

Abstract: A proximity charger roller is disposed in proximity to a surface of an image carrier and uniformly charges an effective charging area of the image carrier. Abutting portions abut on the image carrier at its both edges which are located on the outer side of the effective charging area, thereby maintaining the proximity distance between the circumferential surface of the proximity charger roller and the image carrier constant. A cleaning roller is longer than the spacing between the abutting portions which are at the both edges, abuts on the abutting portions which are at the both edges, and presses with predetermined pressing force in the direction of the image carrier. The surface of the cleaning roller is made of a soft material and cleans a surface area between the two abutting portions of the proximity charger roller.

Abstract: A charging roller is provided. The charging roller is configured to face an image carrier at a predetermined charging gap and charge the image carrier in a non-contact state. A conductive shaft is provided with a pair of annular concave portions formed on an outer circumferential surface at both ends thereof. A conductive layer is formed on the outer circumference surface at a center portion of the conductive shaft defined between the pair of concave portions. An insulating layer is formed on the outer circumferential surface at outer portions of the conductive shaft from the pair of annular concave portions. A depth of the concave portions is larger than a thickness of the conductive layer.

Abstract: An image forming apparatus has an image carrier with rotary shafts extending from both ends that are rotatably supported on an apparatus body by bearings. Gap members fixed to both end portions of a charging roller are brought in contact with the peripheral surface of the image carrier with some pressure to form a charge gap between the image carrier and the charging roller so that the charging roller charges the image carrier in a non-contact state with the charge gap. The gap members have a small-diameter portion on the inside thereof and a large-diameter portion on the outside thereof such that the small-diameter portions face each other.

Abstract: A CPU 113 executes a control program stored in a memory 116 thereby forming a plurality of patch images with a developing bias increased for each of the patch images; detecting a density of each of the patch images by means of a patch sensor 17; and comparing the image densities to determine whether the image density is saturated or not. Then, an image forming condition in which an image density is substantially saturated is determined and is stored in the memory 116. When a print command signal is inputted from an external device via a main controller 100, a printing operation is performed under the image forming condition stored in the memory 116.

Abstract: A CPU 113 executes a control program stored in a memory 116 thereby forming a plurality of patch images with a developing bias increased for each of the patch images; detecting a density of each of the patch images by means of a patch sensor 17; and comparing the image densities to determine whether the image density is saturated or not. Then, an image forming condition in which an image density is substantially saturated is determined and is stored in the memory 116. When a print command signal is inputted from an external device via a main controller 100, a printing operation is performed under the image forming condition stored in the memory 116.