Abstract: A developing blade has a protrusion that protrudes toward a developing roller in an opposing portion facing the developing roller. When a height of the protrusion from an opposing surface that faces the developing roller at a position further toward a tip side than the protrusion is denoted by H (mm) and a length of the opposing surface extending toward the tip side perpendicular to an axial line direction of the developing roller is denoted by L (mm), when viewing a cross section perpendicular to a rotation axis of the developing roller, the following conditions are satisfied: 0.05?H?0.3, and 0.15?L?1.0.

Abstract: An image forming apparatus includes an acquiring portion that acquires a duration of an overcharged state occurring in an area of an image bearing body charged by a charging member after the image bearing body is exposed by a preliminary exposing portion. Adjustment is made to an interval between a first timing when the preliminary exposing portion starts exposing the image bearing body before execution of an adjustment operation for setting a transfer voltage value and a second timing when a voltage applying portion starts, during the subsequent adjustment operation, applying a voltage with an adjustment voltage value to a transfer member such that the second timing is later than a third timing when the duration acquired by the acquiring portion ends.

Abstract: An image forming apparatus includes an acquiring portion that acquires a duration of an overcharged state occurring in an area of an image bearing body charged by a charging member after the image bearing body is exposed by a preliminary exposing portion. Adjustment is made to an interval between a first timing when the preliminary exposing portion starts exposing the image bearing body before execution of an adjustment operation for setting a transfer voltage value and a second timing when a voltage applying portion starts, during the subsequent adjustment operation, applying a voltage with an adjustment voltage value to a transfer member such that the second timing is later than a third timing when the duration acquired by the acquiring portion ends.

Abstract: An image forming apparatus includes: a first exposing unit exposing a surface of a charged photosensitive member to form a latent image; a second exposing unit exposing the surface of the photosensitive member after the surface of the photosensitive member passes a transfer position at which a toner image obtained by causing toner to adhere to the latent image is transferred to a transferred body and before the surface of the photosensitive member reaches a charging position; and a control unit varying a length of a period from a timing at which a portion of the photosensitive member exposed by the second exposing unit is initially charged by the charging member to a timing at which the first exposing unit starts formation of the latent image when performing image formation based on a print signal, based on information related to a photosensitive layer thickness of the photosensitive member.

Abstract: An image forming apparatus includes a developing device, a detection mode execution unit, and a notice signal generating unit. The developing device supplies a toner bearing member with toner in a container by rotating a toner supply member in a contact manner with the toner bearing member. The detection mode execution unit executes a detection mode in which a predetermined period for changing a toner amount in the foam layer by rotating the toner supply member is provided, a capacitance C1 between the first and second electrode members is detected before the predetermined period, and a capacitance C2 between the first and second electrode members is detected after the predetermined period. The notice signal generating unit generates a low toner amount notice signal in response to an absolute value |C1?C2| of a difference between the capacitances C1 and C2 being smaller than a predetermined threshold.

Abstract: An image forming apparatus includes a developing device, a detection mode execution unit, and a notice signal generating unit. The developing device supplies a toner bearing member with toner in a container by rotating a toner supply member in a contact manner with the toner bearing member. The detection mode execution unit executes a detection mode in which a predetermined period for changing a toner amount in the foam layer by rotating the toner supply member is provided, a capacitance C1 between the first and second electrode members is detected before the predetermined period, and a capacitance C2 between the first and second electrode members is detected after the predetermined period. The notice signal generating unit generates a low toner amount notice signal in response to an absolute value |C1?C2| of a difference between the capacitances C1 and C2 being smaller than a predetermined threshold.

Abstract: A restricting blade includes: a metallic plate subjected to punching; a contact surface perpendicular to a thickness direction of the metallic plate, the surface being positioned upstream in a punch direction; an end surface of the metallic plate, formed by the punching, the surface being positioned at the metallic plate upstream in a rotational direction of the developing roller; and a coating layer formed in such a manner as to cover a part of a surface positioned opposite to the contact surface in the thickness direction of the metallic plate and the end surface with a resin or an elastomer.

Abstract: An image forming apparatus includes a rotatable image bearing member on which an electrostatic latent image is formed; a charging member for being supplied with a charging voltage which is a DC voltage not having an AC voltage component and for contacting the bearing member to electrically charge a surface of the bearing member using an electric discharge; a transfer member for transferring onto a transfer material a toner image formed on the surface of the bearing member by developing the electrostatic latent image, at a transfer position; wherein the charging potential of the charging member is different between when the charging member provides a first region with a potential and when the charging member provides a second region with a potential, thus providing a predetermined potential difference between the first region and the second region, and wherein the transfer member is not supplied with a voltage when the second region is at the transfer position, where the first region is a region on the image b

Abstract: An image forming apparatus includes an image bearing member and a charging roller rotatable in contact therewith. Before driving of the image bearing member starts, a bias having the same polarity as that of an image forming bias is applied between the charging roller and the image bearing member. The time of application of the bias varies with the accumulated time of rotation of the image bearing member or the time of making the driving of the image bearing member inactive.

Abstract: A charging device for electrically charging an image bearing member, includes a contact charging member contactable to the image bearing member to charge the image bearing member, the contact charging member being supplied only with a DC voltage; and a contact member contacted to the charging member, wherein the image bearing member is adapted to carry a toner image of toner which contains an externally added material comprising silica, wherein work functions of the charging member, the contact member and the silica satisfy, (the work function of the contact member)>(the work function of the silica)>(the work function of the charging member).

Abstract: An image forming apparatus includes a rotatable image bearing member on which an electrostatic latent image is formed, a charging member, and a transfer member. A charging potential of the charging member is different between when the charging member provides a first region on the image bearing member with a potential and when the charging member provides a second region on the image bearing member with a potential, thus providing a predetermined potential difference between the first region and the second region. A third region on the image bearing member, with the transfer member being supplied with a voltage to provide a predetermined potential difference between a potential of the third region before being charged by the charging member and a potential of the third region after being charged by the charging member.

Abstract: An image forming apparatus includes a rotatable image bearing member on which an electrostatic latent image is formed; a charging member for being supplied with a charging voltage which is a DC voltage not having an AC voltage component and for contacting the bearing member to electrically charge a surface of the bearing member using an electric discharge; a transfer member for transferring onto a transfer material a toner image formed on the surface of the bearing member by developing the electrostatic latent image, at a transfer position; wherein the charging potential of the charging member is different between when the charging member provides a first region with a potential and when the charging member provides a second region with a potential, thus providing a predetermined potential difference between the first region and the second region, and wherein the transfer member is not supplied with a voltage when the second region is at the transfer position, where the first region is a region on the image b

Abstract: An electrophotographic image forming apparatus for forming an image on a recording material, to which a cartridge is detachably mountable. The cartridge includes portion for accommodating a developer for developing an electrostatic latent image formed on an electrophotographic photosensitive member, a roller for developing the electrostatic latent image with the developer, an opening for supplying the developer to the developing roller from the developer accommodating portion, and a sealing member for unsealably sealing the developer supply opening. The apparatus includes a detector for detecting that amount of the developer deposited on a member to be detected is less than a predetermined level, a retractor for producing an electric signal for retracting the sealing member from a sealing position where the sealing member seals the developer supply opening, when the detector detects that amount of the developer deposited on the member to be detected is less than the predetermined level.

Abstract: A developing apparatus including: a developer carrying member for carrying a developer, the developer carrying member being provided with an elastic layer and adapted to develop, with a developer, an electrostatic image formed on an image bearing member; wherein the developer includes a toner, the toner has a shape factor SF-1 of 100 or more but less than 130, the toner has a storage modulus G? (140° C.) at 140° C. of 2.0×103 dN/m2 or more but less than 2.0×104 dN/m2, the toner has a temperature, when the toner has a viscosity of 1.0×103 Pa·s in a flow tester temperature elevation method, of 115° C. or more but less than 130° C., and, in a surface roughness of the developer carrying member, a center-line mean roughness Ra, a ten-point mean roughness Rz and a mean spacing Sm of irregularities satisfy following relationships (1): 0.06 ? Rz / Sm ? 0.4 0.8 ? Ra ? 2.0 ? ? ( ? ? ? m ) } .

Abstract: A color electrophotographic image forming apparatus for forming an image on a recording material, includes (i) a mounting portion for detachably mounting process cartridges developing images with different colors and each including an electrophotographic photosensitive drum and a developing roller for developing an latent image formed on the drum, wherein roller is movable between a contact state contacting the drum and a spaced state spaced from the drum; (ii) a switching device switching the rollers between the contact and spacing states; (iii) a feeding belt for feeding the recording material along all of the drums; (iv) a controller for switching between a first monochrome mode in which the belt contacts all of the drums and a second monochrome mode in which the belt contacts only the drum of the cartridge which develops the latent image for image formation.

Abstract: A charging device for electrically charging an image bearing member, includes a contact charging member contactable to the image bearing member to charge the image bearing member, the contact charging member being supplied only with a DC voltage; and a contact member contacted to the charging member, wherein the image bearing member is adapted to carry a toner image of toner which contains an externally added material comprising silica, wherein work functions of the charging member, the contact member and the silica satisfy, (the work function of the contact member)>(the work function of the silica)>(the work function of the charging member).

Abstract: An image forming apparatus includes a rotatable image bearing member on which an electrostatic latent image is formed; a charging member for being supplied with a charging voltage which is a DC voltage not having an AC voltage component and for contacting the bearing member to electrically charge a surface of the bearing member using an electric discharge; a transfer member for transferring onto a transfer material a toner image formed on the surface of the bearing member by developing the electrostatic latent image, at a transfer position; wherein the charging potential of the charging member is different between when the charging member provides a first region with a potential and when the charging member provides a second region with a potential, thus providing a predetermined potential difference between the first region and the second region, and wherein the transfer member is not supplied with a voltage when the second region is at the transfer position, where the first region is a region on the image b

Abstract: An electrophotographic image forming apparatus for forming an image on a recording material, to which a cartridge is detachably mountable, includes a) a cartridge including, a developer accommodating portion for accommodating a developer for developing an electrostatic latent image formed on an electrophotographic photosensitive member, a developing roller for developing an electrostatic latent image with a developer, a developer supply opening for supplying the developer to the developing roller form the developer accommodating portion, and a sealing member for unsealably sealing the developer supply opening; b) developer detecting means for detecting that amount of the developer deposited on a member to be detected is less than a predetermined level; c) sealing member retracting means for producing an electric signal for retracting the sealing member sealing the developer supply opening from a sealing position where the sealing member seals the developer supply opening, when the detecting means detects that

Abstract: A developing apparatus including: a developer carrying member for carrying a developer, the developer carrying member being provided with an elastic layer and adapted to develop, with a developer, an electrostatic image formed on an image bearing member; wherein the developer includes a toner, the toner has a shape factor SF-1 of 100 or more but less than 130, the toner has a storage modulus G? (140° C.) at 140° C. of 2.0×103 dN/m2 or more but less than 2.0×104 dN/m2, the toner has a temperature, when the toner has a viscosity of 1.0×103 Pa·s in a flow tester temperature elevation method, of 115° C. or more but less than 130° C., and, in a surface roughness of the developer carrying member, a center-line mean roughness Ra, a ten-point mean roughness Rz and a mean spacing Sm of irregularities satisfy following relationships (1): 0.06 ? Rz / Sm ? 0.4 0.8 ? Ra ? 2.

Abstract: A color electrophotographic image forming apparatus for forming an image on a recording material, includes (i) a mounting portion for detachably mounting a plurality of process cartridges each including an electrophotographic photosensitive drum and a developing roller for developing an latent image formed on the drum, wherein developing roller is movable between a contact state where the developing roller is contacted to the drum and a spaced state where the developing roller is spaced from the drum, wherein the cartridges develop the latent images with colors different from each other; (ii) switching means for switching the developing rollers between the contact state and the spacing state when the cartridges are set in the mounting portions; (iii) a feeding belt for feeding the recording material along all of the drums of the cartridges set in the mounting portion; (iv) control means for switching, in accordance with a kind of the recording material in a monochromatic mode operation, between a first mode i