Patent ID: 8050593

Claim:
In an image forming apparatus comprising: a main apparatus body; a process unit including at least one of an image carrier, a charging unit, a developing device and a toner accommodating unit, the process unit is detachably mounted to the main apparatus body in an insertion direction orthogonal to a width direction of the process unit, which is a vertical direction of the main apparatus body; a convex section of the process unit that projects from a bottom side of the process unit; an engagement section of a top side of the main apparatus body that positions the process unit in the width direction by engaging with the convex section if the process unit is mounted to the main apparatus body and the top side of the main apparatus body faces the bottom side of the process unit in the insertion direction; and a guidance section that guides the convex section towards the engagement section, if the process unit is mounted, the guidance section being on at least one of a tip end of the convex section and the main apparatus body, wherein the convex section and the engagement section each include a straight section that extends in the insertion direction and contact between the straight section of the convex section and the straight section of the engagement section positions the process unit in the width direction.