US 12,687,811 B2Granted

Image forming apparatus with control of suction forces in suction fans during sheet conveyance

AssigneeCanon Kabushiki Kaisha

InventorMasashi Takano

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Abstract

An image forming apparatus includes a transfer unit, a fixing unit, a conveyance unit, and a control unit. The control unit selectively performs a plurality of modes including a first mode and a second mode. The first mode is a mode in which, when a grammage of a sheet is a first grammage, if a leading edge of the sheet has reached the fixing unit, the control unit controls the first suction unit such that suction force of the first suction unit becomes first suction force. The second mode is a mode in which, when the grammage of the sheet is a second grammage smaller than the first grammage, if a leading edge of the sheet has reached the fixing unit, the control unit controls the first suction unit such that the suction force of the first suction unit becomes second suction force smaller than the first suction force.

Claims10

Dependent claims

An image forming apparatus comprising:

a transfer unit including a transfer nip portion configured to nip and convey a sheet, the transfer unit being configured to transfer a toner image borne on an image bearing member onto the sheet nipped by the transfer nip portion;
a fixing unit including a fixing nip portion configured to nip and convey the sheet, the fixing unit being configured to fix the toner image transferred onto the sheet by the transfer unit on the sheet;
a conveyance unit configured to convey the sheet from the transfer unit toward the fixing unit, the conveyance unit including:
an endless belt configured to convey the sheet supported on a conveyance surface of the endless belt;
a first suction fan configured to suck the sheet onto a first area of the conveyance surface;
and
a second suction fan configured to suck the sheet onto a second area of the conveyance surface, the second area being upstream of the first area in a sheet conveyance direction;
a guide configured to guide the sheet conveyed by the endless belt to the fixing unit, the guide being located intersecting with an imaginary plane extending the conveyance surface of the endless belt as viewed in a sheet width direction intersecting with the sheet conveyance direction;
and
a control unit configured to control a suction force of the first suction fan and a suction force of the second suction fan so that:
the suction force of the first suction fan is smaller than the suction force of the second suction fan before a leading end of the sheet reaches the fixing nip portion;
and
the suction force of the first suction fan remains smaller than the suction force of the second suction fan in a state where the leading end of the sheet reaches the fixing nip portion.

10 more elements

An image forming apparatus comprising:

a transfer unit including a transfer nip portion configured to nip and convey a sheet, the transfer unit being configured to transfer a toner image borne on an image bearing member onto the sheet nipped by the transfer nip portion;
a fixing unit including a fixing nip portion configured to nip and convey the sheet, the fixing unit being configured to fix the toner image transferred onto the sheet by the transfer unit on the sheet;
a conveyance unit configured to convey the sheet from the transfer unit toward the fixing unit, the conveyance unit including:
an endless belt configured to convey the sheet is supported on an upper surface of the endless belt;
a plurality of supporting portions configured to support the endless belt and including a first supporting portion and a second supporting portion, the first supporting portion being located at the highest position among the plurality of supporting portions, the second supporting portion being located at the second highest position among the plurality of supporting portions;
a first suction fan disposed between the first supporting portion and the second supporting portion in a sheet conveyance direction and configured to suck the sheet onto the upper surface;
and
a second suction fan disposed between the first supporting portion and the second supporting portion in the sheet conveyance direction and configured to suck the sheet onto the upper surface, wherein the second suction fan is disposed upstream of the first suction fan;
and
a control unit configured to control a suction force of the first suction fan and a suction force of the second suction fan so that:
the suction force of the first suction fan is smaller than the suction force of the second suction fan before a leading end of the sheet reaches the fixing nip portion;
and
the suction force of the first suction fan remains smaller than the suction force of the second suction fan in a state where the leading end of the sheet reaches the fixing nip portion.

10 more elements

Dependencies are inferred from the claim text.

Facts

Application: 19/031,082Filed 17 Jan 2025 · continuation
Priority: JP 2022-1269239 Aug 2022
Published: US 2025/0164916 A122 May 2025
Granted: 21 Jul 2026
Term ends: Not estimatedThe source records don’t support an estimate.

Classification4 codes

G03G 15/6529
Apparatus which relate to the handling of copy material: transporting
G03G 15/657
Handling of sheet copy material taking place in a specific part of the copy material feeding path: feeding path after the transfer point and up to…
G03G 2215/00413
The feeding path segment where particular handling of the copy medium occurs, segments being adjacent and non-overlapping. Each segment is…:…
G03G
Electrography

Family

Application18/364,009Parent of this continuation · filed 2 Aug 2023
US 2025/0164916 A1Pre-grant publication · published 22 May 2025
US 12,228,875 B2Parent of this continuation
US 2024/0053698 A1Published application
US 12,687,811 B2This patent

From the US filing history. Foreign family members aren’t listed.