Image forming apparatus facilitating detachment of toner cartridge from process cartridge attached to housing of image forming apparatus

An image forming apparatus comprising:

• a housing having an opening;
• a top cover pivotally movable about a pivot axis relative to the housing between a closed position where the top cover closes the opening and an open position where the top cover opens the opening;
• a photosensitive drum;
• a drum frame supporting the photosensitive drum;
• a developing roller configured to supply toner to the photosensitive drum;
• a developing frame supporting the developing roller;
• a toner cartridge attachable to and detachable from the drum frame, the toner cartridge being configured to supply toner to the developing roller, the toner cartridge being pivotally movable relative to the drum frame;
• and
• an exposure head provided at the top cover, the exposure head being configured to expose the photosensitive drum to light, the exposure head being movable between an exposure position, where the exposure head exposes the photosensitive drum to light, and an outside position, where the exposure head is positioned outside the housing, the exposure head being at the exposure position when the top cover is at the closed position, and the exposure head being at the outside position when the top cover is at the open position,
• wherein pivotal movement of the toner cartridge is in interlocking with pivotal movement of the top cover,
• wherein the toner cartridge is pivotally movable between
• an attachment/detachment position, where the toner cartridge is attachable to and detachable from the drum frame, and
• a fixed position, where the toner cartridge is fixed to the drum frame,
• wherein the toner cartridge is configured such that, when the toner cartridge pivotally moves from the fixed position to the attachment/detachment position, an upper end of the toner cartridge moves away from the pivot axis of the top cover in a horizontal direction, and
• wherein a space occupied by the toner cartridge when the toner cartridge is at the attachment/detachment position is overlapped with a space occupied by the exposure head when the exposure head is at the exposure position.