Rotary developing apparatus rotatably accommodating a plurality of developer units, developer unit and image forming apparatus including rotary developing apparatus

An image forming apparatus having a developing apparatus, the developing apparatus comprising:

• a plurality of developer units each having a toner storage that stores toner therein and a developing chamber including a supply roller and a developing roller;
• a rotary rack that accommodates the developer units therein;
• and
• a driver that drives the rotary rack to rotate in a predetermined rotational direction to bring a targeted one of the developer units to a developing position, wherein
• as the rotary rack rotates in the rotational direction, the toner flows in a predetermined flowing direction in the toner storage,
• when the targeted developer unit is located within a predetermined range of the rotation, the toner is supplied from the toner storage to the developing chamber through a toner supply opening,
• an inner wall of the toner storage includes a first part and a second part with the toner supply opening located therebetween, the first part being located upstream of the second part in the flowing direction, and the second part being stationary with respect to the first part during rotation of the rotary rack and having an edge adjacent the toner supply opening that is closer to the first part than outer surfaces of the supply roller and the developing roller, and
• in a plane that is orthogonal to a rotation axis of the rotary rack, the first part is sloped downward in the developing position from an upstanding side wall inside the toner storage toward the second part in a direction which the toner is supplied into the toner supply opening before entering the developing chamber, the first part being sloped at a first angle that is smaller than 180° .

A developer unit being one of a plurality of developer units accommodated in a rotary rack of a developing apparatus, the developing apparatus driving the rotary rack to rotate in a predetermined rotational direction to bring a targeted one of the developer units to a developing position, the developer unit comprising:

• a toner storage that stores toner therein;
• a developing chamber that is adjacent to the toner storage via a partition part;
• and
• a developing roller and a supply roller that are disposed in the developing chamber, wherein
• the partition part has a toner supply opening through which the toner flows from the toner storage into the developing chamber,
• an inner wall of the toner storage includes a first part and a second part with the toner supply opening located therebetween, the second part being stationary with respect to the first part during rotation of the rotary rack and having an edge adjacent the toner supply opening that is closer to the first part than outer surfaces of the supply roller and the developing roller, and
• in a plane that is orthogonal to a rotation axis of the developing roller, the first part is sloped downward in the developing position from an upstanding side wall inside the toner storage toward the second part in a direction which the toner is supplied into the toner supply opening before entering the developing chamber, the first part being sloped at a first angle that is smaller than 180° .