Printing medium supply device and image forming apparatus having the same

An image forming apparatus comprising:

• an image forming apparatus main body;
• and
• a printing medium supply device to supply a printing medium into the image forming apparatus main body,
• wherein the printing medium supply device includes:
• a printing medium supply device case;
• a shaft rotated by a drive source and pivotally rotatably supported by the printing medium supply device case;
• a pickup roller spaced apart from the shaft so as to come into contact with the printing medium;
• a pickup holder configured to support the pickup roller, the pickup holder being rotated about the shaft to lift or lower the pickup roller;
• a link member configured to be pivotally rotated along with the pickup holder;
• a pressure member having a pressure applying portion formed at one end thereof to apply pressure to the link member;
• and
• an elastic member to generate elastic force for pickup pressure of the pickup roller to be applied to the printing medium, one end of the elastic member being fixed to the pressure member,
• wherein a distance between a pressure applied portion, located on the link member to correspond to the pressure applying portion of the pressure member, and a center of the shaft varies based on a position of the link member.

A printing medium supply device comprising:

• a pickup roller spaced apart from a shaft and configured to come into contact with a printing medium;
• a pickup holder configured to support the pickup roller, the pickup holder being pivotally rotated along with the shaft to lift or lower the pickup roller;
• a link member provided at the pickup holder to adjust pressure to be applied to the pickup roller;
• an elastic member to provide the pickup roller with pickup force for the printing medium;
• and
• a pressure member connected to one end of the elastic member to apply pressure to the link member.

A printing medium supply device comprising:

• a pickup holder, one side of which is rotatable about a first axis;
• a pickup roller supported by the other side of the pickup holder so as to be vertically moved via rotation of the pickup holder, the pickup roller being rotatable about a second axis to come into contact with a printing medium and pick up the printing medium;
• a pressure member to apply pressure to the pickup holder, the pressure member being rotatable about a third axis;
• and
• an elastic member to elastically bias the pressure member so that the pressure member rotates the pickup holder to push the pickup roller toward the printing medium.