Abstract: An image forming apparatus includes a rotatable photosensitive member; a charging portion, an exposure portion, a developing member, a transfer unit, a contact and separation portion, a charging voltage applying portion, a detecting portion, and a controller. The controller is capable of executing an operation in an image forming mode and an operation in a detecting mode. The controller carries out control so that a charging current flowing through a charging portion during charging of the photosensitive member in the operation in the detecting mode is lower than a charging current flowing through the charging portion during charging of the photosensitive member in the operation in the image forming mode.

Abstract: An image forming apparatus includes an image bearing member, a developing unit, a moving mechanism capable of moving the developing unit to a first position and a second position apart from the image bearing member further than the first position. A control portion controls to execute an image forming operation in which a toner image is formed with the toner according to the image information. A consumption amount acquiring portion acquires consumption amount of the toner based on the image information. The control portion controls the moving mechanism to execute a moving operation in which the developing unit is moved from the second position to the first position after the developing unit is moved from the first position to the second position in a non-image forming period in a case in which the consumption amount of the toner is equal to or more than a predetermined threshold value in the second image forming operation.

Abstract: A developer used in a developing apparatus equipped with a metal blade includes a toner base particle and external additives, the external additives including a silica particle with a particle diameter of 5 nm or more and 25 nm or less and an inorganic spacer particle with a particle diameter of 50 nm or more and 150 nm or less, and an area occupancy of the silica particle on a surface of the toner base particle is 40% or more.

Abstract: An image forming apparatus includes a rotatable photosensitive member; a charging portion, an exposure portion, a developing member, a transfer unit, a contact and separation portion, a charging voltage applying portion, a detecting portion, and a controller. The controller is capable of executing an operation in an image forming mode and an operation in a detecting mode. The controller carries out control so that a charging current flowing through a charging portion during charging of the photosensitive member in the operation in the detecting mode is lower than a charging current flowing through the charging portion during charging of the photosensitive member in the operation in the image forming mode.

Abstract: A developer used in a developing apparatus equipped with a metal blade includes a toner base particle and external additives, the external additives including a silica particle with a particle diameter of 5 nm or more and 25 nm or less and an inorganic spacer particle with a particle diameter of 50 nm or more and 150 nm or less, and an area occupancy of the silica particle on a surface of the toner base particle is 40% or more.

Abstract: A developer used in a developing apparatus equipped with a metal blade includes a toner base particle and external additives, the external additives including a silica particle with a particle diameter of 5 nm or more and 25 nm or less and an inorganic spacer particle with a particle diameter of 50 nm or more and 150 nm or less, and an area occupancy of the silica particle on a surface of the toner base particle is 40% or more.

Abstract: A developer used in a developing apparatus equipped with a metal blade includes a toner base particle and external additives, the external additives including a silica particle with a particle diameter of 5 nm or more and 25 nm or less and an inorganic spacer particle with a particle diameter of 50 nm or more and 150 nm or less, and an area occupancy of the silica particle on a surface of the toner base particle is 40% or more.

Abstract: A developer bearing member including: a rotational shaft; and an elastic layer on an outer circumference surface of the rotational shaft, developer being borne on a surface of the elastic layer, wherein the elastic layer is configured such that a load per unit area of a contact portion between one surface of a flat glass plate and the surface of the elastic layer is to be 5.8 N/mm2 or more, in a state that the one surface of the flat glass plate being parallel with an axis direction of the rotational shaft and the one surface of the flat glass plate coming into contact with the surface of the elastic layer with a predetermined penetration level, and wherein a ten-point average roughness Rzjis on the surface of the elastic layer is greater than a volume-average particle diameter of a particle of the developer.

Abstract: When a new development device is mounted, a control unit of an image forming apparatus identifies a development device type. When an identification result corresponds to a first development device containing a first amount of developer, an agitation member operates in a first mode. When the identification result corresponds to a second development device containing a second amount of developer higher than the first amount, the agitation member operates in a second mode. A second operation amount of the agitation member in the second mode is higher than a first operation amount of the agitation member in the first mode. A developer containing chamber of the development device is provided with a discharge opening from which the developer is discharged. The operations in the first and second modes are performed after a sealing member sealing the discharge opening is removed and also before a normal image forming process is executed.

Abstract: A developer bearing member including: a rotational shaft; and an elastic layer on an outer circumference surface of the rotational shaft, developer being borne on a surface of the elastic layer, wherein the elastic layer is configured such that a load per unit area of a contact portion between one surface of a flat glass plate and the surface of the elastic layer is to be 5.8 N/mm2 or more, in a state that the one surface of the flat glass plate being parallel with an axis direction of the rotational shaft and the one surface of the flat glass plate coming into contact with the surface of the elastic layer with a predetermined penetration level, and wherein a ten-point average roughness Rzjis on the surface of the elastic layer is greater than a volume-average particle diameter of a particle of the developer.

Abstract: A developing apparatus, includes: a developer bearing member configured to bear a developer; and a regulating member that is disposed in contact with a surface of the developer bearing member, and configured to regulate the developer borne on the developer bearing member. On the surface of the developer bearing member, a conductive portion having a first surface roughness and first electric resistance, and a dielectric portion having a second surface roughness, which is smaller than the first surface roughness, and second electric resistance, which is larger than the first electric resistance, are disposed. In a case where the developer borne on the developer bearing member is charged by friction with the regulating member, a charging polarity of the dielectric portion is the same polarity as a charging polarity of the developer.

Abstract: A process cartridge includes a developer carrier including a dielectric portion and a conductive portion on a surface thereof, a regulation member, and an image carrier disposed so as to come into contact with the developer carrier. The developer carrier and the image carrier are rotationally driven such that a surface of the developer carrier and a surface of the image carrier move at linear velocities different from each other at a contact portion, and the developer remaining on the image carrier after the developer image is transferred from the image carrier, is collected by the developer carrier at the contact portion.

Abstract: A developing apparatus, includes: a developer bearing member configured to bear a developer; and a regulating member that is disposed in contact with a surface of the developer bearing member, and configured to regulate the developer borne on the developer bearing member. On the surface of the developer bearing member, a conductive portion having a first surface roughness and first electric resistance, and a dielectric portion having a second surface roughness, which is smaller than the first surface roughness, and second electric resistance, which is larger than the first electric resistance, are disposed. In a case where the developer borne on the developer bearing member is charged by friction with the regulating member, a charging polarity of the dielectric portion is the same polarity as a charging polarity of the developer.

Abstract: A process cartridge includes a developer carrier including a dielectric portion and a conductive portion on a surface thereof, a regulation member, and an image carrier disposed so as to come into contact with the developer carrier. The developer carrier and the image carrier are rotationally driven such that a surface of the developer carrier and a surface of the image carrier move at linear velocities different from each other at a contact portion, and the developer remaining on the image carrier after the developer image is transferred from the image carrier, is collected by the developer carrier at the contact portion.

Abstract: A process cartridge configured to be detachably attachable to a main body of an electrophotographic image forming apparatus, in which an occurrence of an image failure is suppressed, wherein the process cartridge includes an electrophotographic photosensitive member and a cleaning member arranged in contact with the electrophotographic photosensitive member, wherein an elastic deformation modulus of a surface layer of the electrophotographic photosensitive member is 35% or larger, and the cleaning member is formed of a urethane foam, wherein a density of the urethane foam is 200 to 500 kg/cm3, and a 25% compressive load of the urethane foam is 0.3 MPa or smaller.

Abstract: A developing apparatus includes a developer carrying member, a developer container, and a regulating member to regulate the thickness of the developer. The regulating member includes a support member having one end fixed to the developer container and the other end free, with the support member extending in a direction opposite to the rotating direction of the developer carrying member, and a contact member to be fixed to the other end of the support member and to contact the developer carrying member. The contact member includes a contact curved surface along a peripheral surface of the developer carrying member, and an opposite surface to face the developer carrying member. The contact pressure of the contact curved surface applied to the developer carrying member decreases as a location on the developer carrying member approaches a downstream side in the rotating direction.

Abstract: A regulating portion includes a first contact portion, a second contact portion, opposed surface portion, and a second opposed surface portion. When, in a plane orthogonal to the rotation axis direction of a developer bearing member, the fixed end and the free end of a supporting member are connected by an imaginary straight line, a contact position where the first contact portion contacts the developer bearing member is located on the downstream side, in the rotation direction of the developer bearing member, of a point of contact of a tangent line parallel to the imaginary straight line with the outer periphery of the developer bearing member.

Abstract: When a new development device is mounted, a control unit of an image forming apparatus identifies a development device type. When an identification result corresponds to a first development device containing a first amount of developer, an agitation member operates in a first mode. When the identification result corresponds to a second development device containing a second amount of developer higher than the first amount, the agitation member operates in a second mode. A second operation amount of the agitation member in the second mode is higher than a first operation amount of the agitation member in the first mode. A developer containing chamber of the development device is provided with a discharge opening from which the developer is discharged. The operations in the first and second modes are performed after a sealing member sealing the discharge opening is removed and also before a normal image forming process is executed.

Abstract: A relation between a first thickness of a resin layer in an upstream portion of a contact nip in which the resin layer that covers a supporting member of a regulating blade makes contact with a developing roller and a second thickness of the resin layer in a downstream portion of the contact nip is set such that the second thickness is smaller than the first thickness. A potential difference having the same polarity as a toner charging polarity toward the supporting member is created between the supporting member and the developing roller.

Abstract: A process cartridge configured to be detachably attachable to a main body of an electrophotographic image forming apparatus, in which an occurrence of an image failure is suppressed, wherein the process cartridge includes an electrophotographic photosensitive member and a cleaning member arranged in contact with the electrophotographic photosensitive member, wherein an elastic deformation modulus of a surface layer of the electrophotographic photosensitive member is 35% or larger, and the cleaning member is formed of a urethane foam, wherein a density of the urethane foam is 200 to 500 kg/cm3, and a 25% compressive load of the urethane foam is 0.3 MPa or smaller.