Separation roller, sheet feeding apparatus, and image forming apparatus

A sheet feeding apparatus comprising:

• a sheet supporting portion configured to support a sheet;
• a rotary feeding member configured to feed the sheet supported on the sheet supporting portion;
• and
• a separation roller disposed to oppose the rotary feeding member and configured to separate one sheet fed by the rotary feeding member from another sheet in a nip portion formed between the separation roller and the rotary feeding member,
• wherein the separation roller comprises:
• an outer circumferential portion formed from an elastic material in a tubular shape and configured to come into contact with the sheet in the nip portion;
• a core portion configured to support an inner circumferential surface of the outer circumferential portion;
• and
• a flange portion comprising a plurality of projecting portions provided at a plurality of positions in a circumferential direction and each projecting to an outside in a radial direction with respect to the core portion,
• wherein, in a state in which the outer circumferential portion is not worn, an outer diameter of the outer circumferential portion is larger than an outer diameter of the flange portion, and
• wherein the plurality of projecting portions are configured such that, in a state in which the outer diameter of the outer circumferential portion has become smaller than the outer diameter of the flange portion, conveyance of the sheet by the rotary feeding member is hindered by any one of the plurality of projecting portions abutting a leading end of the sheet in a sheet feeding direction of the rotary feeding member.

A separation roller for a sheet feeding apparatus, the separation roller comprising:

• an outer circumferential portion formed from an elastic material in a tubular shape and configured to come into contact with a sheet in a nip portion between the separation roller and a rotary feeding member of the sheet feeding apparatus;
• a core portion to which the outer circumferential portion is attached;
• and
• a flange portion comprising a plurality of projecting portions provided at a plurality of positions in a circumferential direction and each projecting to an outside in a radial direction with respect to the core portion, the flange portion being disposed outside of the outer circumferential portion in an axial direction of the separation roller,
• wherein an outer diameter of the outer circumferential portion is larger than an outer diameter of the flange portion, and
• wherein at least one of the plurality of projecting portions comprises a first surface provided on a side portion thereof on an upstream side in a first direction, the first direction being a rotation direction in which the separation roller rotates in such a manner as to follow the rotary feeding member rotating to feed the sheet, the first surface extending more upstream in the first direction at a position further on an outside in a radial direction with respect to a rotation axis of the separation roller as viewed in the axial direction.

A separation roller for a sheet feeding apparatus, the separation roller comprising:

• an outer circumferential portion formed from an elastic material in a tubular shape and configured to come into contact with a sheet in a nip portion between the separation roller and a rotary feeding member of the sheet feeding apparatus;
• a core portion configured to support an inner circumferential surface of the outer circumferential portion;
• and
• a flange portion comprising a plurality of projecting portions provided at a plurality of positions in a circumferential direction and each projecting to an outside in a radial direction with respect to the core portion,
• wherein, in a state in which the outer circumferential portion is not worn, an outer diameter of the outer circumferential portion is larger than an outer diameter of the flange portion, and
• wherein the plurality of projecting portions are configured such that, in a state in which the outer diameter of the outer circumferential portion has become smaller than the outer diameter of the flange portion, conveyance of the sheet by the rotary feeding member is hindered by any one of the plurality of projecting portions abutting a leading end of the sheet in a sheet feeding direction of the rotary feeding member.