A positively chargeable toner includes a plurality of toner particles each including a toner mother particle and an external additive attached to a surface of the toner mother particle. The external additive includes first resin particles each having a surface to which a cationic surfactant is attached and second resin particles each having a surface to which a cationic surfactant is attached. The first resin particles have a hydrophobicity of at least 15% and no greater than 30%. The second resin particles have a hydrophobicity of at least 50% and no greater than 80%. A first resin particle coverage ratio and a second resin particle coverage ratio each are at least 10% and no greater than 30%. Each blocking rate of the first resin particles and the second resin particles is no greater than 30% by mass.

In a case where a collection mode in which an exposure unit forms a first potential on a photosensitive member and a developing unit collects discharging toner discharged from the developing unit to a position where the first potential is formed is executed, a potential forming unit forms, on an intermediate transfer member, a potential same as a normal charging polarity of toner and an absolute value greater than an absolute value of the first potential, and a charging power supply applies, to a charging member, a voltage having a polarity same as the normal charging polarity and an absolute value greater than an absolute value of the first potential.

A positively chargeable toner includes a plurality of toner particles each including a toner mother particle and an external additive attached to a surface of the toner mother particle. The external additive includes first resin particles each having a surface to which a cationic surfactant is attached and second resin particles each having a surface to which a cationic surfactant is attached. The first resin particles have a hydrophobicity of at least 15% and no greater than 30%. The second resin particles have a hydrophobicity of at least 50% and no greater than 80%. A first resin particle coverage ratio and a second resin particle coverage ratio each are at least 10% and no greater than 30%. Each blocking rate of the first resin particles and the second resin particles is no greater than 30% by mass.

A sheet-conveying device includes first, second, and third rotary members, and a switching unit. The first rotary member rotates in one direction to convey, with the second rotary member, a sheet in a first direction and to convey, with the third rotary member, the sheet in a second direction. The switching unit switch from a first to a second state by moving the first rotary member before a trailing end of the first direction conveyed sheet passes through the first and second rotary members. The first state is a state where the second rotary member contacts a first surface of the sheet and the first rotary member contacts a second surface of the sheet. The second state is a state where the first rotary member contacts with the first surface of the sheet and the third rotary member contacts the second surface of the sheet.

An image forming apparatus includes an image carrier, an electrification device, an exposing device, developing device, and a control unit. The developing device includes a developing roller for supplying toner to the image carrier, a developing container for storing developer containing the toner, and a seal member for preventing leakage of the toner from a gap between the image carrier and the developing container. The control unit is capable of executing a seal member cleaning mode, in which it forms an electrostatic latent image pattern having exposed parts and unexposed parts whose boundaries exist at a predetermined or less interval over the entire area in a width direction of an image forming area of the image carrier when an image is not being formed, and drives the image carrier to rotate so that the electrostatic latent image pattern passes the seal member.

A sheet conveying device, which is included in an image forming apparatus and a post processing device, includes a position corrector and either one of a rolling body and a contact resistance reducer. The position corrector is configured to convey a sheet and correct a position of the sheet. The rolling body is disposed at least one of an upstream side and a downstream side of a sheet conveyance passage from the position corrector in a sheet conveying direction and is configured to roll in at least a direction intersecting the sheet conveying direction. The contact resistance reducer is configured to reduce contact resistance generated due to contact of the sheet to a neighboring part when the position of the sheet is corrected by the position corrector.

An image forming apparatus includes a rotatable roller member held in press-contact with an image bearing member, and a deformation determining unit that determines deformation of the roller member based on a value of a current flowing between the roller member and the image bearing member in response to application of a voltage to the roller member. The deformation determining unit performing detection of the deformation of the roller member in response to a predetermined indication before start of an image forming operation. In addition, a restoring unit restores deformation of the roller member based on a detection result of the deformation determining unit.

In a case where a collection mode in which a exposure unit forms a first potential on a photosensitive member and a developing unit collects discharging toner discharged from the developing unit to a position where the first potential is formed is executed, a potential forming unit forms, on an intermediate transfer member, a potential same as a normal charging polarity of toner and an absolute value greater than an absolute value of the first potential, and a charging power supply applies, to a charging member, a voltage having a polarity same as the normal charging polarity and an absolute value greater than an absolute value of the first potential.

An image forming apparatus includes an image carrier, an electrification device, an exposing device, developing device, and a control unit. The developing device includes a developing roller for supplying toner to the image carrier, a developing container for storing developer containing the toner, and a seal member for preventing leakage of the toner from a gap between the image carrier and the developing container. The control unit is capable of executing a seal member cleaning mode, in which it forms an electrostatic latent image pattern having exposed parts and unexposed parts whose boundaries exist at a predetermined or less interval over the entire area in a width direction of an image forming area of the image carrier when an image is not being formed, and drives the image carrier to rotate so that the electrostatic latent image pattern passes the seal member.

A discharging method used in an image forming apparatus includes discharging, with an exposure device, an exposure range of the latent image bearer, and discharging, with a discharger, an area of the latent image bearer outside the exposure range and inside a developing range in a main scanning direction. The exposure range is inside the developing range in the main scanning direction. The discharging with the exposure device and the discharging with the discharger are performed when a rotation of the latent image bearer is stopped after a toner image is transferred from the latent image bearer.