A developing cartridge includes: a casing; a developer container; a developing roller; an unsealing mechanism; a first rotary body; a second rotary body; and a delayed transmission mechanism. The developer container is sealed to accommodate developer. The unsealing mechanism unseals the developer container. The first rotary body is provided at the unsealing mechanism. A drive force from a drive source is transmitted to the first rotary body and the second rotary body. The second rotary body transmits the drive force to the developing roller. The delayed transmission mechanism delays transmission of the drive force to the second rotary body for at least a prescribed time after transmission of the drive force to the first rotary body is initiated. The prescribed time is equivalent to a time that elapses from a moment the unsealing mechanism begins rotating to a moment the unsealing mechanism has unsealed the developer container.

When a position of a developing unit with respect to a photoreceptor unit, the developing unit being mounted in an image forming apparatus, is switched to a contact position from a separation position with a switching unit, the developing unit at the contact position is brought to a state forming a predetermined space with the guide unit through which an airflow generated by a fan and that flows in a longitudinal direction of the guide unit flows, and when the position of the developing unit with respect to the photoreceptor unit, the developing unit being mounted in the image forming apparatus, is switched to the separation position from the contact position with the switching unit, the developing unit at the separation position is brought to a state in which the developing unit enters at least a portion of an area of the predetermined space.

A developer cartridge may include a gear configured to be movable between an enagement position in which the gear engages an auger or supply gear to provide toner from a toner container to a developing unit and a disengaged position in which the gear does not engage the auger or supply gear. The gear may be moved by a cam and/or cam gear from the engagement position to the disengaged position and vice versa. The cam gear may include toothless and toothed portions to allow the developer cartridge to maintain the movable gear in either the engagement position or the disengaged position. In some arrangements, an urging member such as a spring may bias the cam gear in a rotation direction, while a lever may provide a counteracting force when the movable gear is to be maintained in a particular position.

A developer carrying member is disposed below a storage chamber of a frame and has a surface configured such that a plurality of dielectric portions are dispersed on a conductive portion, an upper region of the storage chamber of the frame is enlarged further in a horizontal direction than a lower region in which the developer carrying member is disposed, and the frame has a lower guide surface and includes a curved surface having a tangent plane inclined at a first angle equal to or greater than a degree of an angle of repose of the developer and less than 90 degrees, in an inner wall of the lower region, and an upper guide surface includes a curved surface having a tangent plane inclined at a second angle that is less than the first angle relative to a horizontal plane in an inner wall of the upper region.

An example image forming apparatus includes a main body, a driving motor rotatable in a first direction to provide a driving force to a developing cartridge and rotatable in a second direction opposite to the first direction, and a support assembly to, based on the developing cartridge being mounted to the main body, provide the driving force of the driving motor in the first direction to the mounted developing cartridge, and detach the mounted developing cartridge from the main body using the driving force of the driving motor in the second direction.

A toner includes toner particles, each including: a toner base particle including a binder resin, a colorant, and wax; and resin particles on a surface of the toner base particle, wherein Formulae 1 to 3 below are satisfied, where M is a volume average primary particle diameter (nm) of the resin particles, and L is a distance (nm) between the resin particles present next to one another on the surface of the toner base particle:

M<L;  (Formula 1)

5 (nm)<M≤60 (nm); and  (Formula 2)

0.40≤[M (nm)/L (nm)]<0.90.  (Formula 3)

A toner case includes a case main body, an attachment member, and a sealing member. The case main body is configured to contain a toner. The attachment member is configured to partition an inside space of the case main body so as to adjust toner capacity. The sealing member is arranged between the case main body and the attachment member. The case main body includes a first engagement part. The attachment member includes a second engagement part configured to engage with the first engagement part via the sealing member.

A powder container case includes a first member, a second member, a main joint, and an additional joint. The first member and the second member are joined to form an edge portion of a case opening. The main joint is disposed between the first member and the second member, and has an end portion at the edge portion of the case opening. The additional joint is disposed adjacent to the end portion of the main joint.

A developing device to prevent damage of a memory unit and poor connection between terminals of the memory unit and a main body of an image forming apparatus, by improving a mounting position of the memory unit. The developing device is removably mounted to a main body of the image forming apparatus. The memory unit includes terminals exposed through a rear side of the developing device. The memory unit is disposed closer to a power reception unit formed at one side of the developing device than to a driving force reception unit formed at an other side of the developing device.

An image forming apparatus includes: a first guide that is provided in an apparatus housing and configured to suspend and hold a first unit including an image holder so that the first unit is movable in an insertion and removal direction; a second guide that is provided in the apparatus housing and configured to suspend and hold a second unit including a developer holder so that the second unit is movable in an insertion and removal direction; and a pedestal that is disposed on a front side in the insertion and removal direction with respect to the first guide and the second guide, supports, from below in a gravity direction, the first unit and the second unit while the first unit and the second unit are inserted into the apparatus housing, and does not contact with the first unit and the second unit located in the apparatus housing.