Patent ID: 8346133

Claim:
An image-forming device comprising: a plurality of image carrying members provided for respective colors and aligned in a first direction in a main casing; a plurality of developing units provided in one-to-one correspondence with the plurality of image carrying members, each of the plurality of developing units including a developer carrying member that supplies developer to the corresponding image carrying members; first and second contact/separation members linearly movable in the first direction, in a second direction perpendicular to the first direction, the first contact/separation member and the second contact/separation member being disposed one on either side of the plurality of developing units in opposition with each other, the first contact/separation member being disposed on one side of each developing unit, and the second contact/separation member being disposed on the other side of each developing unit, and a synchronous moving mechanism that linearly moves the first and second contact/separation members in synchronization with each other, wherein each of the first and second contact/separation members includes a plurality of cam parts in one-to-one correspondence with the plurality of developing units, the plurality of cam parts being formed integrally with a corresponding one of the first and second contact/separation members, the first and second contact/separation members linearly move in the first direction to move at least one of the plurality of developing units between a contact position where the developer carrying member contacts the corresponding image carrying member and a separating position where the developer carrying member separates from the corresponding image carrying member, the developing unit is on the corresponding cam part at the separating position and the developing unit is out of the corresponding cam part at the contact position, the plurality of cam parts is configured to be arranged at intervals in the first direction so that one of the plurality of developing units remains at the contact position and the remaining developing units are moved to the separating positions in a case that the first and second contact/separation members linearly move by a predetermined distance, a first interval of one pair of two adjacent cam parts is longer than a second interval of the remaining pair of two adjacent cam parts, and the plurality of developing units includes respective protruding parts, and each of the first and second contact/separation members has a plurality of contact surfaces and a plurality of separating surfaces paired with the corresponding cam parts, wherein the protruding parts of the developing units at the contact positions contact the corresponding contact surfaces, and the protruding parts of the developing units at the separating positions contact the corresponding separating surfaces.