Fixing device and image forming apparatus
10627756 ยท 2020-04-21
Assignee
Inventors
- Takashi Eiki (Osaka, JP)
- Hiroki Kawasaki (Osaka, JP)
- Atsushi Kohama (Osaka, JP)
- Yuhiro Sakai (Osaka, JP)
Cpc classification
G03G2215/2035
PHYSICS
G03G15/2017
PHYSICS
G03G15/161
PHYSICS
G03G15/2053
PHYSICS
International classification
Abstract
A fixing device includes a cylindrical rotatable fixing belt, a flat heater, a heater holding part, a pressuring member, and a connector. In the flat heater, an electrode part, a feeder and a heat generating part are formed in the same face state. The heater holding part holds the flat heater so that the heat generating part faces to an inner circumference face of the fixing belt. The pressuring member sandwiches the fixing belt with the flat heater. The connector has a contacting portion coming into contact with the electrode part. The feeder has a portion arranged at a near side from the electrode part in an attaching direction of the connector. The heater holding part includes a protecting portion covering the portion of the feeder arranged at the near side from the electrode part.
Claims
1. A fixing device comprising: a cylindrical rotatable fixing belt being long in an axial direction; a flat heater in which an electrode part, a feeder and a heat generating part are formed in the same face state; a heater holding part holding the flat heater so that the heat generating part faces to an inner circumference face of the fixing belt; a pressuring member being long in the axial direction and sandwiching the fixing belt with the flat heater; and a connector having a contacting portion coming into contact with the electrode part and being attached to the heater holding part along a face on which the electrode part is formed in a direction orthogonal to the axial direction, wherein the heat generating part includes a first heat generating part arranged at a center in the axial direction within a range corresponding to a small size sheet and second heat generating parts at both sides from the first heat generating part in the axial direction within a range corresponding to a large size sheet, the electrode part includes a first electrode part connecting to the first heat generating part by a first feeder, a second electrode part connecting to the second heat generating parts respectively by a second feeder and a third feeder, and a third electrode part connecting to the third heat generating part by a fourth feeder, the first electrode part, the second electrode part, and the third electrode part being arranged in parallel along the axial direction at one end side in the axial direction, the first feeder is arranged at a far side from the first electrode part in an attaching direction of the connector, the second feeder is connected to the second heat generating part at one end side in the axial direction and arranged at a far side from the second electrode part in the attaching direction of the connector, and the fourth feeder is arranged at another end side from the third electrode part in the axial direction, the third feeder is connected to the second heat generating part at the another end side in the axial direction and has a portion arranged at a near side from the second electrode part in an attaching direction of the connector, the heater holding part includes a protecting portion covering the portion of the third feeder arranged at the near side from the second electrode part.
2. The fixing device according to claim 1, wherein the protecting portion is integrally formed with the heater holding member.
3. An image forming apparatus comprising: an image forming part forming a toner image on a sheet; and the fixing device according to claim 2 to fix the toner image on the sheet.
4. The fixing device according to claim 1, wherein the protecting portion is a different member from the heater holding member.
5. An image forming apparatus comprising: an image forming part forming a toner image on a sheet; and the fixing device according to claim 4 to fix the toner image on the sheet.
6. The fixing device according to claim 1, wherein the protecting portion has insulation property and high heat conductivity.
7. An image forming apparatus comprising: an image forming part forming a toner image on a sheet; and the fixing device according to claim 6 to fix the toner image on the sheet.
8. The fixing device according to claim 1, wherein the connector has a recessed portion penetrating in the axial direction, the attaching direction of the connector is orthogonal to the axial direction, the connector is attached to the heater holding part by fitting the heater holding part holding the flat heater into the recessed portion.
9. The fixing device according to claim 8, wherein as the contacting portion, two contacting portions are respectively provided on an upper inner face and a lower inner face of the recessed portion so as to protrude to a lower side and an upper side.
10. An image forming apparatus comprising: an image forming part forming a toner image on a sheet; and the fixing device according to claim 9 to fix the toner image on the sheet.
11. An image forming apparatus comprising: an image forming part forming a toner image on a sheet; and the fixing device according to claim 8 to fix the toner image on the sheet.
12. An image forming apparatus comprising: an image forming part forming a toner image on a sheet; and the fixing device according to claim 1 to fix the toner image on the sheet.
13. A fixing device comprising: a cylindrical rotatable fixing belt; a flat heater in which an electrode part, a feeder, and a heat generating part are formed in the same face state; a heater holding part holding the flat heater so that the heat generating part faces to an inner circumference face of the fixing belt; a pressuring member sandwiching the fixing belt with the flat heater; and a connector having a contacting portion coming into contact with the electrode part, wherein the feeder has a portion arranged at a near side from the electrode part in an attaching direction of the connector, the heater holding part includes a protecting portion covering the portion of the feeder arranged at the near side from the electrode part, and the protecting portion has insulation property and high heat conductivity.
14. An image forming apparatus comprising: an image forming part forming a toner image on a sheet; and the fixing device according to claim 13 to fix the toner image on the sheet.
15. A fixing device comprising: a cylindrical rotatable fixing belt; a flat heater in which an electrode part, a feeder, and a heat generating part are formed in the same face state; a heater holding part holding the flat heater so that the heat generating part faces to an inner circumference face of the fixing belt; a pressuring member sandwiching the fixing belt with the flat heater; and a connector having a contacting portion coming into contact with the electrode part, wherein the feeder has a portion arranged at a near side from the electrode part in an attaching direction of the connector, the heater holding part includes a protecting portion covering the portion of the feeder arranged at the near side from the electrode part, the connector has a recessed portion penetrating in an axial direction, the attaching direction of the connector is orthogonal to the axial direction, the connector is attached to the heater holding part by fitting the heater holding part holding the flat heater into the recessed portion, and as the contacting portion, two contacting portions are respectively provided on an upper inner face and a lower inner face of the recessed portion so as to protrude to a lower side and an upper side.
16. An image forming apparatus comprising: an image forming part forming a toner image on a sheet; and the fixing device according to claim 15 to fix the toner image on the sheet.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DETAILED DESCRIPTION
(13) Hereinafter, with reference to the accompanying drawings, embodiments of an image forming apparatus and a fixing device of the present disclosure will be described.
(14) First, the entire structure of a printer 1 as the image forming apparatus will be described with reference to
(15) In an apparatus body 2 of the printer 1, a sheet feeding cartridge 3 storing sheets S, a sheet feeding device 5 feeding the sheet S from the sheet feeding cartridge 3, an image forming part 7 forming a toner image on the sheet S, a fixing device 9 fixing the toner image on the sheet S, a sheet ejecting device 11 ejecting the sheet S, and an ejected sheet tray 13 receiving the ejected sheet S are provided. Further, in the apparatus body 2, a conveying path 15 of the sheet S is arranged so as to run from the sheet feeding device 5 to the sheet ejecting device 11 through the image forming part 7 and the fixing device 9.
(16) The sheet S fed from the sheet feeding cartridge 3 by the sheet feeding device 5 is conveyed to the image forming part 7 along the conveying path 15 and the toner image is formed on the sheet S. The sheet S is conveyed to the image fixing device 9 along the conveying path 15 and the toner image is fixed on the sheet S. The sheet S having the fixed toner is ejected from the sheet ejecting device 11 to the ejected sheet tray 13.
(17) Next, the fixing device 9 will be described with reference to
(18) The fixing device 9 includes a cylindrical shaped rotatable fixing belt 21, the flat heater 23, the heater holding member 25, a pressuring roller 27, and the connector 26. In the flat heater 23, electrode parts 51, 52 and 54, feeders 61 to 64, and heat generating parts 41 to 43 are formed in the same face state. The heater holding member 25 holds the flat heater 23 so that the heat generating parts 41 to 43 face to an inner circumference face of the fixing belt 21. The pressuring roller 27 sandwiches the fixing belt 21 with the flat heater 23. The connector 26 has contacting portions 267 and 268 coming into contact with the electrode parts 51, 52 and 54. The feeder 63 has a portion being arranged at a near side from the electrode parts 52 and 54 in an attaching direction of the connector 26, and the heater holding member 25 includes a protecting portion 255 covering the portion of the feeder 63 arranged at the near side from the electrode parts 52 and 54. In the following description, an axial direction X indicates an axial direction of the pressuring roller 27 (forward and backward directions). Although, in the present embodiment, an example of the fixing device 9 arranged in a posture that the pressuring roller 27 is located below the fixing belt 21, the fixing device 9 may be arranged in any of various postures.
(19) As shown in
(20) As shown in
(21) The base material is made of material, such as ceramic, with electrical insulation property, and is formed in a roughly rectangular plate shape having a longitudinal direction along the axial direction X. The heat insulation layer 31 is made of material, such as ceramic or glass, with electrical insulation property and low heat conductivity, and is laminated on a lower face of the base material. The heat insulation layer 31 restrains conducting of heat generated by the heat generating parts 41 to 43 to a side of the base material.
(22) The heat generating parts 41 to 43 are made of material, such as metal, with electrical conductivity having a resistance value higher than the feeders 61 to 64, and are formed on a lower face of the heat insulation layer 31. The heat generating parts 41 to 43 are arranged along one line parallel to the axial direction X. Each of the heat generating parts 41 to 43 has a plurality of resistance heat generating elements 40 arranged along one line parallel to the axial direction X.
(23) The heat generating part 41 is arranged within a range corresponding to a length of a longer side of the sheet S of a small size (e.g. JIS A5 size). The heat generating parts 42 and 43 are arranged within a range corresponding to a length of a longer side of the sheet S of a large size (e.g. JIS A4 size) where the heat generating part 41 is not arranged. The heat generating parts 42 and 43 are respectively located at a front side and a rear side of the heat generating part 41.
(24) The feeders 61 to 64 are made of material, such as metal, with electrical conductivity having a resistance value lower than the resistance heat generating element 40, and are formed on the lower face of the heat insulation layer 31. The feeder 61 is connected to right ends (ends at an upstream side in a conveying direction Y of the sheet S) of the plurality of resistance heat generating elements 40 included in the heat generating part 41. The feeder 62 is connected to right ends of the plurality of resistance heat generating elements 40 included in the heat generating part 42. The feeder 63 is connected to right ends of the plurality of resistance heat generating elements 40 included in the heat generating part 43. On the other hand, the feeder 64 is connected to left ends (ends at a downstream side in the conveying direction Y) of the plurality of resistance heat generating elements 40 included in the heat generating parts 41 to 43. The electrode parts 51, 52 and 54 are located at a front side portion from the heat generating part 42 on the lower face of the heat insulation layer 31 in order of the electrode parts 51, 52, 54 from the front side.
(25) The feeder 61 is connected to the electrode part 51, the feeders 62 and 63 are connected to the electrode part 52, and the feeder 64 is connected to the electrode part 54. However, although the feeders 61 and 62 are arranged at right side portions (at the upstream side in the conveying direction Y) from the heat generating parts 41 and 42, the feeder 63 is arranged from a right end of the heat generating part 43 through a rear side portion from the heat generating part 43 and left side portions (at the downstream side in the conveying direction Y) from the heat generating parts 43, 42 and 41 and the electrode parts 54 and 52, and is connected to the electrode part 52. Incidentally, on the lower face of the heat insulation layer 31, in portions in which the heat generating parts 41 to 43, the feeders 61 to 64 and the electrode parts 51 to 54 are not formed, the heat insulation layer 31 is laminated so as to form a flat face together with the heat generating parts 41 to 43, the feeders 61 to 64 and the electrode parts 51 to 54.
(26) The coat layer covers a range in the longitudinal direction of the heat insulation layer 31 where the heat generating parts 41 to 43 are formed. The coat layer is made of, for example, material, such as ceramic, with electrical insulation property and small sliding friction force with respect to the fixing belt 21. A lower face of the coat layer comes into contact with the inner circumference face of the fixing belt 21.
(27) As shown in
(28) As shown in
(29) As shown in
(30) As shown in
(31) As shown in
(32) As shown in
(33) In the recessed portion 262, a terminal portion 266 is provided. The terminal portion 266 is a groove-shaped terminal having a recessed portion 269 penetrating in the forward and backward directions, and a thickness in the upward and downward directions of the recessed portion 269 is larger than a thickness of the body portion 251 of the heater holding member 25. In an inner face at an upper side of the recessed portion 269, a contacting portion 267 protruded to the lower side is provided and, in an inner face at a lower side of the recessed portion 269, a contacting portion 268 protruded to the upper side is provided. The contacting portions 267 and 268 are plate spring-shaped contacts having flexibility, and can be respectively pushed to the upper side and the lower side.
(34) Next, with reference to
(35) Firstly, as shown in
(36) Subsequently, as shown in
(37) And then, as shown in
(38) When the connector 26 is further pushed, as shown in
(39) When the connector 26 is furthermore pushed, as shown in
(40) A fixing operation of the fixing device 9 having the above-described configuration will be described. When the pressuring roller 27 is driven and rotated in a predetermined rotating direction Z, the fixing belt 21 is co-rotated with the pressuring roller 27 in an opposite rotating direction to the rotating direction Z of the pressuring roller 27, and the inner circumference face of the fixing belt 21 is slide with respect to the flat heater 23. When power is supply to the heat generating parts 41 to 43 of the flat heater 23, the heat generating parts 41 to 43 generate heat to heat the fixing belt 21. After temperature of the fixing belt 21 reaches predetermined temperature, the sheet S on which the toner is transferred is conveyed to the pressuring area N. In the pressuring area N, the sheet S is sandwiched between the fixing belt 21 and the pressuring roller 27 and conveyed. At this time, the toner is heated and pressured by the fixing belt 21, and them, the toner is fixed on the sheet S. The sheet S on which the toner is fixed is separated from the fixing belt 21 and conveyed along the conveying path 15.
(41) As described above, in accordance with the present embodiment, the feeder 63 arranged at the near side from the electrode parts 52 and 54 in the attaching direction of the connector 26 is covered by the protecting portion 255. Therefore, according to the embodiment, without using a connector having a complicated shape, it is possible to protect the feeder 63 arranged at the near side from the electrode parts 52 and 54 in the attaching direction of the connector 26. Moreover, according to the embodiment, since the protecting portion 255 is made of material having high heat conductivity, it is possible to restrain temperature rise of the portion covered by the protecting portion 255.
(42) Although, in the present embodiment, an example attaching the protecting portion 255 formed in a shape shown in
(43) Although, in the present embodiment, an example providing the protecting portion 255 and the heater holding member 25 as different members is described, in a modified example, the protecting portion 255 may be integrally formed with the heater holding member 25. For instance, after the feeder 63 is formed on the heat insulation layer 31, on its lower face, material having insulation property and high heat conductivity may be laminated, and thereby, the protecting portion 255 may be formed. In such a case, the protecting portion 255 only needs to have an area covering at least the feeder 63.
(44) Although, in the present embodiment, an example that the flat heater 23 has three heat generating parts 41 to 43 is described, in a modified example, regardless of the number of the heat generating parts of the flat heater 23, the present disclosure may be applied in a case where the feeder has the portion arranged at the near side from the electrode parts in the attaching direction of the connector.
(45) Although, in the present embodiment, a case where the present disclosure is applied to the printer 1 has been described as one example, the disclosure is not restricted by this, but may be applied to a copying machine, a facsimile, a multifunction peripheral or the like.
(46) The above-description of the embodiment of the present disclosure was described about a preferable embodiment of the fixing device and the image forming apparatus according to the disclosure. However, the technical scope of the present disclosure is not limited to the embodiments.