Sheet-feeding mechanism, sheet-feeding device, and image forming apparatus

A sheet-feeding device, comprising:

• a) a housing;
• b) a tray for holding sheets;
• c) a sheet-feeding mechanism, including:
• c1) a feeding roller which rotates in a sheet-conveying direction, at least a surface of the feeding roller being flexible;
• and
• c2) a retard roller having a plurality of press-contact rollers, which are arranged on a common axis and come in press-contact with the feeding roller at a predetermined pressure so as to form a plurality of press-contact surfaces, and being rotatable in an opposite direction with respect to the sheet-conveying direction, the plurality of press-contact rollers having a first press-contact roller and a second press-contact roller which are adjacent to each other in an axial direction, and
• c3) a hardness of the feeding roller being smaller than a hardness of the retard roller;
• and
• d) a pick-up roller for conveying sheets held on the tray to the sheet-feeding mechanism, wherein
• a portion of the feeding roller corresponding to an axial clearance between the first press-contact roller and the second press-contact roller is so deformed to bulge toward an axis of the retard roller due to a difference in the hardness between the feeding roller and the press-contact roller.

An image forming apparatus, comprising:

• (A) sheet-feeding device including:
• a) a housing;
• b) a tray for holding sheets;
• c) a sheet-feeding mechanism, including:
• c1) a feeding roller which rotates in a sheet-conveying direction, at least a surface of the feeding roller being flexible;
• and
• c2) a retard roller having a plurality of press-contact rollers, which are arranged on a common axis and come in press-contact with the feeding roller at a predetermined pressure so as to form a plurality of press-contact surfaces, and being rotatable in an opposite direction with respect to the sheet-conveying direction, the plurality of press-contact rollers having a first press-contact roller and a second press-contact roller which are adjacent to each other in an axial direction, and
• c3) a hardness of the feeding roller being smaller than a hardness of the retard roller;
• and
• d) a pick-up roller for conveying sheets held on the tray to the sheet-feeding mechanism;
• and
• (B) an image forming section for forming an image onto a sheet conveyed from the sheet-feeding mechanism of the sheet-feeding device;
• and
• (C) an image fixing section for fixing the image formed on the sheet, and
• a portion of the feeding roller corresponding to an axial clearance between the first press-contact roller and the second press-contact roller is deformed to bulge toward an axis of the retard roller due to a difference in the hardness between the feeding roller and the press-contact rollers.