Image forming apparatus including transfer device located above photosensitive drum

An image forming apparatus comprising:

• a main housing;
• a drum unit attachable to the main housing, the drum unit including:
• a photosensitive drum rotatable about an axis extending in a first direction;
• a development roller;
• a supply roller;
• an agitator;
• and
• a development housing having a first development chamber and a second development chamber, the development housing including a wall having an opening, the first development chamber and the second development chamber being in communication with each other through the opening, the first development chamber accommodating the agitator, the second development chamber accommodating the development roller and the supply roller, the second development chamber being located above the first development chamber;
• a toner cartridge configured to contain toner to be supplied to the first development chamber of the development housing, the toner cartridge being attachable to the main housing;
• and
• a transfer device located above the photosensitive drum in a state where the drum unit is attached to the main housing, the transfer device being configured to transfer toner on the photosensitive drum to a sheet,
• the agitator including:
• a shaft rotatably supported by the development housing;
• and
• a blade rotatable together with the shaft, the blade having a first end fixed to the shaft and a second end located away from the first end,
• the agitator being configured such that, when rotated, the second end of the blade reaches a height of the opening in a vertical direction,
• wherein the development housing defining the first development chamber includes:
• a first side wall located at one side in the first direction;
• a second side wall located at an other side in the first direction;
• and
• a connection wall connecting the first side wall and the second side wall, the connection wall having a reception port configured to receive toner from the toner cartridge;
• wherein the reception port is located at a center of the connection wall in the first direction;
• and
• wherein the toner cartridge includes:
• a first portion overlapping the first development chamber of the development housing in a second direction crossing the first direction in a state where the toner cartridge is attached to the main housing;
• and
• a second portion overlapping the drum unit in the first direction in a state where the toner cartridge is attached to the main housing.