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US 9,429,887 B2Granted
Fixing device and image forming apparatus with air flow generator for cooling an internal space of a shaft to which a magnetic core is mounted
AssigneeKYOCERA Document Soultions Inc.
InventorShinobu Ohata
Life of this patent
Estimating the term…
Abstract
A fixing device includes a housing, a magnetic flux generation source, a first rotary body, a second rotary body, a first core, a second core, a shaft portion, a magnetic shielding body and an air flow generator. The shaft portion has a hollow cylindrical shape, holds the second core on a peripheral surface and includes an internal space extending in an axial direction inside. The shaft portion serves as a rotary shaft in the rotation of the second core. The air flow generator generates an air flow flowing in the internal space of the shaft portion from one end side toward the other end side in the axial direction.
Claims13
A fixing device comprising:
- a housing;
- a magnetic flux generation source fixed to the housing and configured to generate a magnetic flux;
- a first rotary body configured to be rotated in a predetermined direction and induction-heated by the magnetic flux;
- a second rotary body configured to be rotated in a predetermined direction, a nip portion through which a sheet carrying a toner image passes being formed between the first and second rotary bodies;
- a first core made of a magnetic material and configured to form a magnetic path, along which the magnetic flux passes, together with the first rotary body;
- a second core made of a magnetic material, arranged between the first core and the first rotary body when viewed from the magnetic path and rotatable in a predetermined direction;
- a shaft portion having a hollow cylindrical shape, configured to hold the second core on a peripheral surface, including an internal space extending along an axial direction inside and serving as a rotary shaft in the rotation of the second core;
- a magnetic shielding body made of a nonmagnetic material, arranged on a peripheral surface of the second core or the shaft portion and configured to shield or suppress the magnetic flux by being located in the magnetic path with rotation about the shaft portion;
- and
- an air flow generator configured to generate an air flow flowing in the internal space from one end side toward the other end side in the axial direction;
- an introducing portion mounted on one end side of the shaft portion in the axial direction and configured to introduce the air flow into the internal space;
- a driving portion for generating a rotational drive force for rotating the shaft portion;
- and
- a transmitting portion coupled to the driving portion and mounted on the other end side of the shaft portion in the axial direction and configured to transmit the rotational drive force to the shaft portion, the transmitting portion including a communication space communicating with the internal space and an exhaust port communicating with the communication space and open on an outer peripheral surface of the transmitting portion, wherein
- the magnetic flux generation source being fixed to the housing to surround the second core extending in the axial direction when viewed in a direction perpendicular to the axial direction;
- the second core includes:
- a center core portion arranged over the entire circumference in a central part of the shaft portion in the axial direction and configured to form the magnetic path in accordance with a first sheet width;
- outer core portions arranged to be adjacent at axially outer sides of the center core portion and partially exposed in a circumferential direction and configured to form the magnetic path in accordance with a second sheet width larger than the first sheet width together with the center core portion;
- and
- the magnetic shielding body is arranged at least in the same areas as the outer core portions in the axial direction to cover areas of the second core or the shaft portion different from exposed areas in the circumferential direction, and
- the introducing portion is made of a hollow cylindrical heat resistant material communicating with the internal space and includes a bearing member configured to rotatably support the one end side of the shaft portion and an introducing tube mounted on the bearing member and configured to introduce the air flow toward the internal space via the bearing member.
18 more elements
A fixing device, comprising:
- a housing;
- a magnetic flux generation source fixed to the housing and configured to generate a magnetic flux;
- a first rotary body configured to be rotated in a predetermined direction and induction-heated by the magnetic flux,
- a second rotary body configured to be rotated in a predetermined direction, a nip portion through which a sheet carrying a toner image passes being formed between the first and second rotary bodies;
- a first core made of a magnetic material and configured to form a magnetic path, along which the magnetic flux passes, together with the first rotary body;
- a second core made of a magnetic material, arranged between the first core and the first rotary body when viewed from the magnetic path and rotatable in a predetermined direction;
- a shaft portion having a hollow cylindrical shape, configured to hold the second core on a peripheral surface, including an internal space extending along an axial direction inside and serving as a rotary shaft in the rotation of the second core;
- a magnetic shielding body made of a nonmagnetic material, arranged on a peripheral surface of the second core or the shaft portion and configured to shield or suppress the magnetic flux by being located in the magnetic path with rotation about the shaft portion;
- and
- an air flow generator configured to generate an air flow flowing in the internal space from one end side toward the other end side in the axial direction;
- a plurality of the hole portions arranged at intervals in a circumferential direction and in the axial direction, the hole portions communicating with the internal space and being open on the peripheral surface of the second core or the magnetic shielding body by penetrating through a wall surface of the shaft portion between one end part and the other end part of the shaft portion, wherein:
- the magnetic flux generation source being fixed to the housing to surround the second core extending in the axial direction when viewed in a direction perpendicular to the axial direction;
- the second core includes:
- a center core portion arranged over the entire circumference in a central part of the shaft portion in the axial direction and configured to form the magnetic path in accordance with a first sheet width;
- outer core portions arranged to be adjacent at axially outer sides of the center core portion and partially exposed in a circumferential direction and configured to form the magnetic path in accordance with a second sheet width larger than the first sheet width together with the center core portion;
- and
- the magnetic shielding body is arranged at least in the same areas as the outer core portions in the axial direction to cover areas of the second core or the shaft portion different from exposed areas in the circumferential direction.
14 more elements
Dependencies are inferred from the claim text.