Medium carrying device and image forming apparatus

A medium carrying device, comprising:

• a first carrying part and a second carrying part that are configured to carry a medium, contact each other and make a nip part therebetween;
• a cover member that is pivotal to open and close with respect to a body of the medium carrying device;
• and
• a guide member that is positioned at a guide position to guide the medium toward the nip part, wherein
• the guide member comprises
• a medium regulation part that has a front end part facing the nip part when the guide member is at the guide position;
• an arm part that extends from the medium regulation part;
• and
• a rotation center that is formed on a distal end side of the arm part that is opposite from a medium regulation part side of the arm part,
• the guide member is rotatable from the guide position in a direction in which the front end part approaches the second carrying part with respect to the body of the medium carrying device,
• the rotation center is positioned at a first carrying part side,
• the guide member rotates between the guide position and a retreat position where the guide member is retreated from the guide position in correspondence with open movements of the cover member,
• a position of the rotation center is maintained while the guide member rotates with respect to the body of the medium carrying device,
• the rotation center of the guide member when the guide member is at the guide position is substantially at the same position as the position of the rotation center of the guide member when the guide member is at the retreat position,
• a distance between the rotation center of the guide member and at least one of the first carrying part and the second carrying part is kept constant while the guide member rotates from the guide position to the retreat position,
• wherein the first carrying part is a first carrying roller, and the second carrying part is a second carrying roller,
• wherein when the guide member is at the guide position, the front end part of the medium regulation part is positioned, in a width view of the medium regulation part, between the nip part and a lower outer-circumference tangent line (L1) of the first roller and the second roller, and
• wherein when the guide member is at the retreat position, the front end part of the medium regulation part is not positioned, in a width view of the medium regulation part, between the nip part and the lower outer-circumference tangent line (L1) of the first roller and the second roller.