Medium feeding cassette and image forming apparatus

A medium feeding cassette for storing a medium, said medium feeding cassette comprising:

• a cassette main body;
• a cassette extension member mounted to said cassette main body so as to be movable with respect to said cassette main body;
• and
• a locking mechanism configured to lock said cassette extension member in a predetermined position with respect to said cassette main body according to a size of said medium,
• wherein said locking mechanism includes a first locking portion and a second locking portion that engage each other so as to lock said cassette extension member in said predetermined position,
• wherein said first locking portion moves in a direction to release locking of said cassette extension member when a force is applied to said cassette extension member in a direction to retract said cassette extension member into said cassette main body,
• wherein said second locking portion is disposed on said cassette extension member,
• wherein said first locking portion is mounted to said cassette main body so as to be movable in a direction perpendicular to a moving direction of said cassette extension member, and
• wherein a first biasing unit is provided for biasing said first locking portion in a direction toward said cassette extension member.

A medium feeding cassette for storing a medium, said medium feeding cassette comprising:

• a cassette main body;
• a cassette extension member mounted to said cassette main body so as to be movable with respect to said cassette main body;
• a rear end guide member provided on said cassette extension member, said rear end guide member defining an upstream end of said medium in a feeding direction of said medium;
• and
• a locking mechanism configured to lock said cassette extension member in a predetermined position with respect to said cassette main body according to a size of said medium,
• wherein said locking mechanism includes a first locking portion and a second locking portion that engage each other so as to lock said cassette extension member in said predetermined position,
• wherein said first locking portion moves in a direction to release locking of said cassette extension member when a force is applied to said cassette extension member in a direction to retract said cassette extension member into said cassette main body,
• wherein said cassette extension member includes:
• a to-be-guided portion guided by a bottom portion of said cassette main body, said bottom portion being configured to define a placing surface on which said medium is placed, said to-be-guided portion including a holding portion that holds said medium in a state where said cassette extension member extends from said cassette main body, and
• a rear cover that covers an upstream end of said medium in said feeding direction, a width of said rear cover in a widthwise direction of said medium being wider than a width of said holding portion in said widthwise direction.

A medium feeding cassette for storing a medium, said medium feeding cassette comprising:

• a cassette main body;
• a cassette extension member mounted to said cassette main body and provided so as to extend from said cassette main body at an upstream side of said cassette main body in a feeding direction of said medium, said cassette extension member being movable with respect to said cassette main body;
• an end guide for defining an end of the medium;
• and
• a locking mechanism configured to lock said cassette extension member in a predetermined position with respect to said cassette main body according to a size of said medium,
• said locking mechanism comprising a first locking portion and a second locking portion that engage each other so as to lock said cassette extension member in said predetermined position, said first locking portion comprising a convex portion and said second locking portion comprising concave portions,
• wherein said concave portions comprise
• a first concave portion that holds said cassette extension member at an extending position where said cassette extension member protrudes from said cassette main body, said first concave portion including an inclined surface that is provided at an upstream side of said first concave portion in said feeding direction of said medium, said first concave portion forming an aperture for receiving a part of the convex portion, the entire aperture having a different shape from the entire part of the convex portion, and
• a second concave portion that holds said cassette extension member at a retracting position where said cassette extension member is retracted from said extending position,
• the locking mechanism includes a flat portion disposed between the first concave portion and the second concave portion;
• a first releasing unit that releases locking of said end guide with respect to said cassette extension member;
• and
• a second releasing unit that releases locking of said cassette extension member by said locking mechanism, said second releasing mechanism being operable independently from said first releasing unit,
• wherein said convex portion moves in a direction to release locking of said cassette extension member when a force is applied to any portion of said cassette extension member in a direction to retract said cassette extension member into said cassette main body.