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US 11,061,353 B2Granted
Image forming apparatus
AssigneeCanon Kabushiki Kaisha
InventorsTakayuki Mizuta, Kenichirou Isobe, Tomooku Koyama
Life of this patent
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Abstract
An upstream roller pair and a downstream roller pair are disposed on a first conveyance path and configured to perform a reverse conveyance operation on a sheet. The upstream roller pair includes a first roller and a second roller abutting with each other. The downstream roller pair is configured to nip and convey a sheet by a third roller and a fourth roller in a state that areas in a width direction where a plurality of first rotary members contact a first surface of a sheet do not overlap with areas in the width direction where a plurality of second rotary members contact a second surface of a sheet opposite to the first surface.
Claims16
An image forming apparatus comprising:
- an image forming portion configured to form an image on a sheet;
- a first conveyance path through which a sheet passes in a case where a sheet on which an image has been formed by the image forming portion is discharged to an outside of the image forming apparatus;
- a second conveyance path which branches from the first conveyance path and through which a sheet passes in a case where a sheet on which an image has been formed by the image forming portion is conveyed toward the image forming portion again;
- an upstream roller pair disposed on the first conveyance path and positioned downstream of, in a sheet discharging direction in the first conveyance path, a position at which the second conveyance path branches from the first conveyance path, the upstream roller pair comprising a first roller and a second roller abutting with each other and being configured to nip and convey a sheet by the first roller and the second roller;
- and
- a downstream roller pair disposed on the first conveyance path and positioned downstream of the upstream roller pair in the sheet discharging direction, the downstream roller pair comprising a third roller including a plurality of first rotary members aligned in a width direction orthogonal to the sheet discharging direction and a fourth roller including a plurality of second rotary members arranged on positions in the width direction alternately with positions of the plurality of first rotary members in the width direction, the plurality of first rotary members being configured to overlap at least partially with the plurality of second rotary members when viewed from the width direction,
- wherein the second roller is a driving roller configured to be rotated by driving force from a driving source,
- wherein an outer circumferential portion of the second roller is made of elastic material,
- wherein outer circumferential portions of the plurality of first rotary members and outer circumferential portions of the plurality of second rotary members are made of material softer than the elastic material,
- wherein the downstream roller pair is configured to nip and convey a sheet by the third roller and the fourth roller in a state that areas in the width direction where the plurality of first rotary members contact a first surface of a sheet do not overlap with areas in the width direction where the plurality of second rotary members contact a second surface of a sheet opposite to the first surface, and
- wherein the image forming apparatus is configured to perform a reverse conveyance operation in which a sheet on which an image has been formed by the image forming portion is conveyed in the sheet discharging direction by both the upstream roller pair and the downstream roller pair and is then conveyed in a reverse direction opposite to the sheet discharging direction to the second conveyance path by both the upstream roller pair and the downstream roller pair.
8 more elements
An image forming apparatus comprising:
- an image forming portion configured to form an image on a sheet;
- a first conveyance path through which a sheet passes in a case where a sheet on which an image has been formed by the image forming portion is discharged to an outside of the image forming apparatus;
- a second conveyance path which branches from the first conveyance path and through which a sheet passes in a case where a sheet on which an image has been formed by the image forming portion is conveyed toward the image forming portion again;
- an upstream roller pair disposed on the first conveyance path and positioned downstream of, in a sheet discharging direction in the first conveyance path, a position at which the second conveyance path branches from the first conveyance path, the upstream roller pair comprising a first roller and a second roller abutting with each other and being configured to nip and convey a sheet by the first roller and the second roller;
- and
- a downstream roller pair disposed on the first conveyance path and positioned downstream of the upstream roller pair in the sheet discharging direction, the downstream roller pair comprising a third roller including a plurality of first rotary members aligned in a width direction orthogonal to the sheet discharging direction and a fourth roller including a plurality of second rotary members arranged on positions in the width direction alternately with positions of the plurality of first rotary members in the width direction, the plurality of first rotary members being configured to overlap at least partially with the plurality of second rotary members when viewed from the width direction,
- wherein the downstream roller pair is configured to nip and convey a sheet by the third roller and the fourth roller in a state that areas in the width direction where the plurality of first rotary members contact a first surface of a sheet do not overlap with areas in the width direction where the plurality of second rotary members contact a second surface of a sheet opposite to the first surface,
- wherein the image forming apparatus is configured to perform a reverse conveyance operation in which a sheet on which an image has been formed by the image forming portion is conveyed in the sheet discharging direction by both the upstream roller pair and the downstream roller pair and is then conveyed in a reverse direction opposite to the sheet discharging direction to the second conveyance path by both the upstream roller pair and the downstream roller pair,
- wherein the second roller is a driving roller configured to be rotated by driving force from a driving source,
- wherein a static friction coefficient of the second roller to plain paper is larger than static friction coefficients of the plurality of first rotary members and the plurality of second rotary members to the plain paper, and
- wherein the upstream roller pair and the downstream roller pair are configured such that a pull-out load to pull out a sheet from the downstream roller pair that is in a stop state is smaller than a pull-out load to pull out a sheet from the upstream roller pair that is in a stop state.
8 more elements
An image forming apparatus comprising:
- an image forming portion configured to form an image on a sheet;
- a first conveyance path through which a sheet passes in a case where a sheet on which an image has been formed by the image forming portion is discharged to an outside of the image forming apparatus;
- a second conveyance path which branches from the first conveyance path and through which a sheet passes in a case where a sheet on which an image has been formed by the image forming portion is conveyed toward the image forming portion again;
- an upstream roller pair disposed on the first conveyance path and positioned downstream of, in a sheet discharging direction in the first conveyance path, a position at which the second conveyance path branches from the first conveyance path, the upstream roller pair comprising a first roller and a second roller abutting with each other and being configured to nip and convey a sheet by the first roller and the second roller, wherein a nip portion at which an outer circumferential surface of the first roller and an outer circumferential surface of the second roller abut with each other extends continuously over an area in the width direction containing an entire image forming area in which the image forming portion can form an image on a sheet;
- and
- a downstream roller pair disposed on the first conveyance path and positioned downstream of the upstream roller pair in the sheet discharging direction, the downstream roller pair comprising a third roller including a plurality of first rotary members aligned in a width direction orthogonal to the sheet discharging direction and a fourth roller including a plurality of second rotary members arranged on positions in the width direction alternately with positions of the plurality of first rotary members in the width direction, the plurality of first rotary members being configured to overlap at least partially with the plurality of second rotary members when viewed from the width direction,
- wherein the downstream roller pair is configured to nip and convey a sheet by the third roller and the fourth roller in a state that areas in the width direction where the plurality of first rotary members contact a first surface of a sheet do not overlap with areas in the width direction where the plurality of second rotary members contact a second surface of a sheet opposite to the first surface, and
- wherein the image forming apparatus is configured to perform a reverse conveyance operation in which a sheet on which an image has been formed by the image forming portion is conveyed in the sheet discharging direction by both the upstream roller pair and the downstream roller pair and is then conveyed in a reverse direction opposite to the sheet discharging direction to the second conveyance path by both the upstream roller pair and the downstream roller pair.
5 more elements
Dependencies are inferred from the claim text.