JP2020101677A - Fixing device and image forming apparatus - Google Patents

Abstract

To provide a fixing device and an image forming apparatus that can prevent the influence of electric noise to prevent a reduction in performance of a thermosensitive body.SOLUTION: A fixing device 12 comprises a fixing belt 16, and a heating unit 20 that faces an inner peripheral surface of the fixing belt 16. The heating unit 20 includes a heater 34 that heats the fixing belt 16, a first thermosensitive body 38 that faces the heater 34, a second thermosensitive body 40 that faces the heater 34, a first cable 48 that is connected to the first thermosensitive body 38, and a second cable 52 that is connected to the second thermosensitive body 40. The first thermosensitive body 38 is connected to a primary-side power supply 50 with the first cable 48, and the second thermosensitive body 40 is connected to a secondary-side power supply 54 with the second cable 52; a first area 64 where the first cable 48 is arranged and a second area 66 where the second cable 52 is arranged are different from each other.SELECTED DRAWING: Figure 5

Description

The present invention relates to a fixing device and an image forming apparatus.

A heating film type fixing device mounted in an electrophotographic image forming apparatus is known. For example, the fixing device described in Patent Document 1 has a heating roller having a heating element therein, and a thermostat having a predetermined distance from the heating roller. The thermostat cuts off the electric power supplied to the heating element when the temperature of the heating roller exceeds the set temperature. The thermostat has electrodes on both sides and is connected to a heating element and a power source through the electrodes.

JP, 2000-356920, A

In addition to the thermostat described in Patent Document 1, generally, heat sensitive bodies such as a thermocut, a thermostat, and a thermistor are often arranged close to each other. The plurality of heat sensitive bodies are respectively connected to the plurality of power sources by a plurality of wirings. Therefore, the wirings may be arranged close to each other or may be arranged to intersect with each other, and electric noise may occur between the wirings due to the influence of the electromagnetic wave generated from the wirings. As a result, the heat sensitive body connected to the wiring may be affected by electrical noise.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a fixing device and an image forming apparatus that can suppress the influence of electrical noise on a heat sensitive body.

A fixing device according to the present invention includes a fixing belt and a heating unit facing the inner peripheral surface of the fixing belt. The heating unit heats the fixing belt, a first heat sensitive body facing the heater, a second heat sensitive body facing the heater, and a first cable connected to the first heat sensitive body. A second cable connected to the second heat sensitive body is included. The first heat sensitive body is connected to a primary side power source by the first cable, the second heat sensitive body is connected to a secondary side power source by the second cable, and a first region in which the first cable is arranged. And the second area in which the second cable is arranged are different from each other.

An image forming apparatus according to the present invention includes the fixing device described above and an image forming unit. The image forming unit forms a toner image on a sheet. The fixing device fixes the toner image on the sheet.

According to the fixing device and the image forming apparatus of the present invention, the influence of electrical noise on the heat sensitive body can be suppressed.

FIG. 1 is a diagram showing an image forming apparatus including a fixing device according to an exemplary embodiment of the present invention. FIG. 3 is a perspective view of the fixing device according to the exemplary embodiment when viewed obliquely from above. FIG. 3 is a sectional view taken along section line III-III in FIG. 2. FIG. 6 is another perspective view of the fixing device according to the present embodiment as seen from an obliquely upper direction. It is the top view which looked at the heating part concerning this embodiment from the upper direction. (A) is a figure which shows the connection of the 1st thermal body and the primary side power supply which concern on this embodiment, (b) is a figure which shows the state which attached the cover part to the 1st thermal body of (a). Is. (A) is a figure which shows the connection of the 2nd thermal body and secondary side power supply which concern on this embodiment, (b) shows the state which attached the cover part to the 2nd thermal body of (a). It is a figure.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts will be denoted by the same reference symbols and description thereof will not be repeated. Further, in the present embodiment, the X axis and the Y axis of the three-dimensional orthogonal coordinate system are parallel to the horizontal direction, and the Z axis is parallel to the vertical direction. The direction along the Y axis is an example of the direction along the “rotation axis” of the “pressurizing member” of the present invention. The direction along the Y axis is an example of the direction along the “rotation axis” of the “fixing belt” of the present invention.

The configuration and operation of the image forming apparatus 2 will be described with reference to FIG. FIG. 1 is a diagram showing an image forming apparatus 2 including a fixing device 12 according to an embodiment of the present invention. The image forming apparatus 2 is, for example, a copying machine, a printer, a facsimile, or a multifunction machine having these functions.

As shown in FIG. 1, the image forming apparatus 2 includes a reading unit 4, a feeding unit 6, a conveying unit 8, an image forming unit 10, a fixing device 12, and a discharging unit 14.

The reading unit 4 reads the image of the document G. The reading unit 4 generates image data from the read image.

The feeding unit 6 accommodates a plurality of sheets S and feeds the sheets S to the conveying unit 8.

The transport unit 8 transports the sheet S. The sheet S is, for example, a sheet made of paper or synthetic resin. The transport unit 8 includes a plurality of transport roller pairs and transports the sheet S to the image forming unit 10.

The image forming unit 10 forms the toner image TN on the sheet S by, for example, an electrophotographic method. Specifically, the image forming unit 10 includes a photosensitive drum, a charging device, an exposure device, a developing device, a replenishing device, a transfer device, a cleaning device, and a charge eliminating device.

The fixing device 12 heats and pressurizes the toner image TN to fix the toner image TN on the sheet S. The transport unit 8 transports the sheet S on which the toner image TN is fixed to the discharge unit 14. The ejection unit 14 ejects the sheet S to the outside of the image forming apparatus 2.

Next, details of the configuration of the fixing device 12 will be described with reference to FIGS. 2 to 4 in addition to FIG. 1. FIG. 2 is a perspective view of the fixing device 12 according to the present exemplary embodiment as seen obliquely from above. FIG. 3 is a sectional view taken along the section line III-III in FIG. FIG. 4 is another perspective view of the fixing device 12 according to the present embodiment as seen from an obliquely upper direction. FIG. 4 is an external view in which the fixing belt 16 is removed from the fixing device 12 of FIG. 2 and the inside of the heating unit 20 is exposed.

As shown in FIG. 2, the fixing device 12 includes a fixing belt 16, a pressure member 18, a heating unit 20, and a pair of belt holding members 22.

The fixing belt 16 is endless. The fixing belt 16 has a substantially cylindrical shape that is rotatable about a rotation axis that is substantially parallel to the rotation axis L, and is flexible. The fixing belt 16 has a plurality of layers. The fixing belt 16 has, for example, a polyimide layer and a release layer formed on the polyimide layer. The release layer is, for example, a heat resistant film made of fluororesin.

The pressing member 18 contacts the outer peripheral surface of the fixing belt 16 to press the fixing belt 16 and rotates about the rotation axis L. The pressure member 18 is, for example, a columnar pressure roller.

The pressure member 18 is pressed by the heater 34 via the fixing belt 16 and is brought into pressure contact with the fixing belt 16. A nip portion N is formed at a position where the pressure member 18 is pressed against the fixing belt 16. When the pressure member 18 is driven and rotated, the fixing belt 16 is driven and rotated by the pressure member 18. The sheet S is conveyed in the sheet conveying direction D2 and passes through the nip portion N, so that the toner image TN is fused and fixed on the sheet S.

The pressing member 18 includes a cylindrical cored bar 24, a cylindrical elastic layer 26, and a release layer 28. An elastic layer 26 is formed around the core metal 24, and a release layer 28 is formed so as to cover the surface of the elastic layer 26. The cored bar 24 is formed of, for example, stainless steel or aluminum. The elastic layer 26 has elasticity and is made of, for example, silicone rubber. The release layer 28 is made of, for example, a fluororesin.

As shown in FIG. 3, the heating unit 20 faces the inner peripheral surface of the fixing belt 16. Details of the heating unit 20 will be described later with reference to FIG. A drive mechanism (not shown) rotationally drives the pressure member 18. The drive mechanism includes, for example, a drive motor and a gear. The drive mechanism is connected to one end of the two longitudinal ends of the cored bar 24 of the pressing member 18.

As shown in FIGS. 3 and 4, the heating unit 20 includes a reinforcing member 30, a biasing member 32, a heater 34, a heater holding unit 36, at least one first heat sensitive body 38, and at least one first heat sensitive body 38. The heat sensitive body 40 includes at least one cover portion 42, at least one cover portion 44, and the belt holding member 22. Each of the first heat sensitive body 38 and the second heat sensitive body 40 may be one or plural. In the present embodiment, the heating unit 20 includes two first heat sensitive bodies 38 and two second heat sensitive bodies 40. The heating unit 20 also includes two cover portions 42 corresponding to the two first heat sensitive bodies 38 and two cover portions 44 corresponding to the two second heat sensitive bodies 40.

As shown in FIG. 3, the reinforcing member 30 contacts the cover portion 44. Specifically, the reinforcing member 30 has a substantially inverted U-shape when viewed in a cross section from the direction along the rotation axis L. The reinforcing member 30 contacts the cover portion 44 and reinforces the heater holding portion 36 via the cover portion 44.

The biasing member 32 biases the second heat sensitive body 40 in the biasing direction D1. As a result, the second heat sensitive body 40 comes into close contact with the heater 34. Although not shown, the other biasing member 32 biases the first heat sensitive body 38 in the biasing direction D1. As a result, the first heat sensitive body 38 comes into close contact with the heater 34.

As shown in FIG. 3, the heater 34 heats the fixing belt 16. The first heat sensitive body 38 and the second heat sensitive body 40 are arranged to face the heater 34. Each of the first heat sensitive body 38 and the second heat sensitive body 40 senses the heat of the heater 34. In the present embodiment, each of the first heat sensitive body 38 and the second heat sensitive body 40 detects the temperature of the heater 34. The heater 34 may be a planar or elongated thin plate-shaped heating element. The heater 34 extends along the rotation axis L of the pressing member 18. The heater 34 is, for example, a ceramic heater, and includes a ceramic substrate and a resistance heating element. The thickness of the heater 34 is, for example, 1 mm.

The heater holding portion 36 is provided so as to face the heater 34 or in contact with the heater 34, and holds the heater 34.

Of the plurality of first heat sensitive bodies 38, one first heat sensitive body 38 may be referred to as a first heat sensitive body 38A, and another one of the first heat sensitive bodies 38 may be referred to as a first heat sensitive body 38B. Of the plurality of second heat sensitive bodies 40, one second heat sensitive body 40 may be described as a second heat sensitive body 40A, and the other second heat sensitive body 40 may be described as a second heat sensitive body 40B.

The cover portion 42 faces the heater 34 via the first heat sensitive body 38. The cover portion 44 faces the heater 34 via the second heat sensitive body 40. Of the plurality of cover portions 42, one cover portion 42 may be referred to as a first cover portion 42A, and the other one cover portion 42 may be referred to as a first cover portion 42B. Of the plurality of cover parts 44, one cover part 44 may be referred to as a second cover part 44A, and the other one cover part 44 may be referred to as a second cover part 44B. Three or more cover portions 42 and cover portions 44 may be provided.

The cover portion 42 is provided so as to cover the first heat sensitive body 38. The first heat sensitive body 38 is attached to the cover portion 42. The cover portion 44 is provided so as to cover the second heat sensitive body 40. The second heat sensitive body 40 is attached to the second cover portion 44B. The cover portion 42 presses the first heat sensitive body 38 toward the heater 34. The cover portion 44 presses the second heat sensitive body 40 toward the heater 34. Therefore, it is possible to suppress the positional deviation between the first heat sensitive body 38 and the second heat sensitive body 40.

The first cover portion 42A is provided so as to cover the first heat sensitive body 38A. The first cover portion 42B is provided so as to cover the first heat sensitive body 38B. The second cover portion 44A is provided so as to cover the second heat sensitive body 40A. The second cover portion 44B is provided so as to cover the second heat sensitive body 40B. The first heat sensitive body 38A is attached to the first cover portion 42A. The second heat sensitive body 40B is attached to the second cover portion 44B.

The first cover portion 42A and the first cover portion 42B may be integrated. The first cover portion 42A and the first cover portion 42B may be connected. Further, the first cover portion 42A and the first cover portion 42B may be separated. Similarly, the second cover portion 44A and the second cover portion 44B may be integrated. The second cover portion 44A and the second cover portion 44B may be connected. Further, the second cover portion 44A and the second cover portion 44B may be separated.

The belt holding member 22 holds the fixing belt 16 (FIG. 2). The pair of belt holding members 22 holds two ends of the fixing belt 16 in the rotation axis direction. Hereinafter, one of the pair of belt holding members 22 may be referred to as a belt holding member 22A, and the other belt holding member 22 may be referred to as a belt holding member 22B. The belt holding member 22A slidably holds one end of the fixing belt 16 in the rotation axis direction. The belt holding member 22B slidably holds the other end of the fixing belt 16 in the rotation axis direction.

Further, the pair of belt holding members 22 fixes the reinforcing member 30 to the heater holding member 36. Specifically, the pair of belt holding members 22 are attached to the reinforcing member 30 and the heater holding member 36 with the reinforcing member 30 and the heater holding member 36 facing each other.

In particular, in the embodiment shown in FIG. 4, both the first heat sensitive body 38 and the second heat sensitive body 40 may be thermocut. Both the first heat sensitive body 38 and the second heat sensitive body 40 may be thermostats. Both the first heat sensitive body 38 and the second heat sensitive body 40 may be thermistors. The first heat sensitive body 38 may be a thermo cut, and the second heat sensitive body 40 may be a thermostat. The first heat sensitive body 38 may be a thermo cut, and the second heat sensitive body 40 may be a thermistor. The first heat sensitive body 38 may be a thermostat and the second heat sensitive body 40 may be a thermistor.

The thermocut is a protective element such as a one-shot type thermostat. The thermo cut cuts off the supply of electric power to the heater 34 when the temperature of the heater 34 is equal to or higher than the threshold value. In particular, in the thermocut, once the power supply is cut off according to the temperature of the heater 34, the power supply is not restored. Therefore, when the temperature of the heater 34 rises excessively, the accuracy of stopping the heating of the fixing belt 16 by the heater 34 can be improved.

The thermostat cuts off the supply of electric power to the heater 34 when the temperature of the heater 34 rises above the threshold value, and then returns the supply of electric power to the heater 34 when the temperature of the heater 34 drops below the threshold value. Therefore, the heating of the fixing belt 16 by the heater 34 can be turned on and off with a fine accuracy corresponding to the temperature change of the heater 34.

The thermistor is a semiconductor element that measures the temperature of the heater 34. The image forming apparatus 2 controls the heater 34 based on the temperature measured by the thermistor. Since the second heat sensitive body 40 is a thermistor, the accuracy of controlling the temperature of the heater 34 can be improved.

Hereinafter, in the present embodiment, each of the first heat sensitive body 38A and the first heat sensitive body 38B is a thermocut or a thermostat. Further, in the present embodiment, each of the second heat sensitive body 40A and the second heat sensitive body 40B is a thermistor.

Next, the detailed configuration of the heating unit 20 will be described with reference to FIGS. 2 and 5. FIG. 5 is a plan view of the heating unit 20 according to the present embodiment as viewed from above.

As shown in FIG. 5, the heating unit 20 has a rectangular shape extending along the direction D in a plan view. The direction D is substantially parallel to the rotation axis L shown in FIG. The longitudinal direction of the heating unit 20 is substantially parallel to the direction D. The direction D corresponds to an example of “predetermined direction”.

The heater holder 36 holds the heater 34 on one surface of the heater holder 36. The heater holding portion 36 has a plurality of ribs on the surface opposite to the surface holding the heater 34. The ribs are formed by standing in a shape that matches the shapes of the first heat sensitive body 38, the second heat sensitive body 40, the cover portion 42, and the cover portion 44. The cover part 42 and the cover part 44 are arranged along the direction D.

38 A of 1st thermosensitive bodies are hold|maintained at 42 A of 1st cover parts, the position is controlled by the rib of the heater holding part 36, and are attached to the heater holding part 36. The first heat sensitive body 38B is held by the first cover portion 42B, the position of which is regulated by the ribs of the heater holding portion 36, and the first heat sensitive body 38B is attached to the heater holding portion 36.

The first heat sensitive body 38A and the first heat sensitive body 38B are connected by a cable 46. The first heat sensitive body 38B is connected to the primary side power supply 50 by the first cable 48. That is, the first heat sensitive body 38A and the first heat sensitive body 38B are connected in series with the primary-side power supply 50 by the cable 46 and the first cable 48. However, the first heat sensitive body 38A and the first heat sensitive body 38B may be independently connected to the primary side power source 50 by cables. The first heat sensitive body 38A and the first heat sensitive body 38B may be connected in parallel to the primary power source 50. The primary-side power supply 50 supplies a relatively large electric power to the first heat sensitive body 38 with a relatively high voltage.

The cover portion 42 includes a first guide member 56 and a first pressing portion 58. The first guide member 56 regulates the arrangement of the cables 46 and the first cables 48, and holds the cables 46 and the first cables 48. Further, the first guide member 56 guides the first cable 48 from the first heat sensitive body 38B to the primary side power supply 50 along the direction D3. The first pressing portion 58 prevents the first cable 48 from bending and the first cable 48 from jumping up from the cover portion 42. The direction D3 is a direction toward the primary side power source 50 among the directions D shown in FIG.

The second heat sensitive body 40A is attached to the second cover portion 44A, the position of which is regulated by the ribs of the heater holding portion 36, and the second heat sensitive body 40A is attached to the heater holding portion 36. The second heat sensitive body 40B is attached to the second cover portion 44B, the position of which is regulated by the rib of the heater holding portion 36, and the second heat sensitive body 40B is attached to the heater holding portion 36.

The second heat sensitive body 40A is connected to the secondary side power source 54 by the second cable 52. The second heat sensitive body 40B is connected to the secondary power supply 54 by the second cable 52. That is, the second heat sensitive body 40A and the second heat sensitive body 40B are independently connected to the secondary power supply 54 by the second cable 52. However, the second heat sensitive body 40</b>A and the second heat sensitive body 40</b>B may be connected to the secondary power source 54 in series by the second cable 52. Further, the second heat sensitive body 40A and the second heat sensitive body 40B may be connected in parallel to the secondary power supply 54 by the second cable 52. The secondary-side power supply 54 steps down the voltage of the primary-side power supply 50 and supplies the second heat sensitive body 40 with electric power of a voltage lower than that of the primary-side power supply 50. That is, the voltage of the power supplied by the primary power supply 50 is higher than the voltage of the power supplied by the secondary power supply 54. The diameter of the first cable 48 is larger than the diameter of the second cable 52. Therefore, the allowable current amount of the first cable 48 is larger than that of the second cable 52. Therefore, the user can widely set the threshold value for cutting off the power supply, and can increase the options for the first heat sensitive body 38.

The first heat sensitive body 38 is arranged closer to the primary power supply 50 than the secondary power supply 54. Therefore, the first cable 48 connected to the first heat sensitive body 38 goes toward the primary power source 50 without approaching the second heat sensitive body 40 and the second cable 52. On the other hand, the second heat sensitive body 40 is arranged closer to the secondary power supply 54 than the primary power supply 50. Therefore, the second cable 52 connected to the second heat sensitive body 40 goes toward the secondary side power supply 54 without approaching the first heat sensitive body 38 and the first cable 48. As a result, the first cable 48 and the second cable 52 are not arranged close to each other and are not arranged to cross each other, so that generation of electrical noise can be suppressed.

The cover portion 44 includes a second guide member 60 and a second pressing portion 62. The second guide member 60 regulates the arrangement of the second cable 52 that connects the second heat sensitive body 40A and the second heat sensitive body 40B to the secondary power supply 54, and holds the second cable 52. The second guide member 60 guides the second cable 52 from the second heat sensitive body 40A in the direction D4 of the secondary power supply 54. That is, the cover part 42 guides the first cable 48 to the primary side power supply 50 by the first guide member 56 and the first pressing part 58. Then, the cover portion 44 guides the second cable 52 to the secondary power source 54 by the first guide member 56 and the first pressing portion 58. Therefore, the first cable 48 and the second cable 52 do not come close to each other and do not intersect with each other, so that generation of electrical noise can be suppressed. The direction D4 is the direction toward the secondary-side power source 54 among the directions D shown in FIG.

In addition, the second pressing portion 62 prevents the second cable 52 from bending or jumping up from the cover portion 44. The direction D3 and the direction D4 are opposite to each other. That is, since the first cable 48 and the second cable 52 are guided in the opposite directions by the second guide member 60, the first cable 48 and the second cable 52 are not arranged close to each other and are not arranged to cross each other. , The influence of electrical noise can be suppressed.

In the heater holding part 36, the first heat sensitive body 38A, the first cover part 42A, the cable 46, the first heat sensitive body 38B, the first cover part 42B, and the first cable 48 are arranged in the first region 64. In the heater holding portion 36, the second heat sensitive body 40A, the second cover portion 44A, the second heat sensitive body 40B, the second cover portion 44B, and the second cable 52 are arranged in the second region 66.

In the present embodiment, the first region 64 is a region on the primary power source 50 side in a region of the fixing device 12 that is roughly divided into two regions sandwiched between the belt holding member 22A and the belt holding member 22B. .. The second region 66 is a region on the side of the secondary power supply 54 in a region of the fixing device 12 that is roughly divided into two regions sandwiched between the belt holding member 22A and the belt holding member 22B.

The first area 64 and the second area 66 are different areas. Therefore, it is possible to prevent the first cable 48 and the second cable 52 from being close to each other, and it is possible to suppress the crossing. As a result, it is possible to suppress the generation of electrical noise due to the proximity or intersection of the first cable 48 and the second cable 52. Since the generation of electric noise can be suppressed, the influence of electric noise on the first heat sensitive body 38 and the second heat sensitive body 40 can be suppressed. As a result, it is possible to prevent the performance of the first heat sensitive body 38 and the second heat sensitive body 40 from being degraded.

Subsequently, referring to FIG. 6A, FIG. 6B, FIG. 7A and FIG. 7B in addition to FIG. 5, the first heat sensitive body 38 and the second heat sensitive body 40, and the cable 46, the first cable 48, and the second cable 52 will be described. FIG. 6A is a diagram showing the connection between the first heat sensitive body 38 and the primary power supply 50 according to the present embodiment. FIG. 6B is a diagram in which the cover portion 42 is attached to the first heat sensitive body 38 of FIG. 6A. FIG. 7A is a diagram showing the connection between the second heat sensitive body 40 and the secondary power source 54 according to the present embodiment. FIG. 7B is the second heat sensitive body 40 of FIG. 7A. It is the figure which attached the cover part 44 to.

As shown in FIG. 6A, each of the first heat sensitive body 38A and the first heat sensitive body 38B includes a first terminal 68 and a second terminal 70. In the first region 64, the second terminal 70 of the first heat sensitive body 38A and the first terminal 68 of the first heat sensitive body 38B are connected by the cable 46. In the first region 64, the first cable 48 connected to the second terminal 70 of the first heat sensitive body 38B extends in the direction opposite to the direction D3, and then is folded back in the first region 64 to the direction. It extends along D3 and is connected to the primary power supply 50. That is, the first heat sensitive body 38A and the first heat sensitive body 38B are connected to the cable 46 and the first cable 48 in the first region 64, and are connected in series with the primary power supply 50. The first terminal 68 of the first heat sensitive body 38A is connected to a wiring member that supplies electric power to the heater 34.

As shown in FIG. 6B, in the first region 64, the first heat sensitive body 38A, the first heat sensitive body 38B, the cable 46, and the first cable 48 have the form shown in FIG. 6A. It is attached to the first cover portion 42A and the first cover portion 42B. When the first heat sensitive body 38A is attached to the first cover portion 42A and the first heat sensitive body 38B is attached to the first cover portion 42B, the cable 46 and the first cable 48 are the first guide member 56 and the first pressing portion. The arrangement is regulated by 58, and the first heat sensitive body 38A and the first heat sensitive body 38B are connected in series to the primary power source 50. Therefore, the first cable 48 arranged in the first region 64 does not approach or intersect with the second cable 52 arranged in the second region 66, so that the influence of electrical noise can be suppressed.

As shown in FIG. 7A, each of the second heat sensitive body 40A and the second heat sensitive body 40B includes a third terminal 72A and a third terminal 72B. In the present embodiment, in the second region 66, the third terminal 72A of the second heat sensitive body 40A and the third terminal 72B of the second heat sensitive body 40B are arranged to face each other. That is, in the second region 66, the second heat sensitive body 40A is arranged with the third terminal 72A facing the secondary power supply 54 side. The second heat sensitive body 40B is arranged with the third terminal 72B facing the opposite side of the secondary power supply 54.

As shown in FIG. 7A, in the second region 66, the second cable 52A connected to the third terminal 72A of the second heat sensitive body 40A extends from the third terminal 72A along the direction D4, and It is connected to the secondary power supply 54. In the second region 66, the second cable 52B connected to the third terminal 72B of the second heat sensitive body 40B extends from the third terminal 72B in the direction opposite to the direction D4, and then in the second region 66. At, the line is folded back, extends in the direction D4, and is connected to the secondary power supply 54.

As shown in FIG. 7B, in the second region 66, the second heat sensitive body 40A, the second heat sensitive body 40B, the second cable 52A, and the second cable 52B are shown in FIG. 7A. It is attached to the second cover portion 44A and the second cover portion 44B in the form shown. The arrangement of the second cable 52A and the second cable 52B is regulated by the second guide member 60 and the second pressing portion 62, and the second heat sensitive body 40A and the second heat sensitive body 40B are independently supplied to the secondary power source 54. Connecting. Therefore, the second cable 52 arranged in the second area 66 does not approach or intersect the first cable 48 arranged in the first area 64, so that the influence of electric noise can be suppressed.

The embodiments of the present invention have been described above with reference to the drawings. However, the present invention is not limited to the above-described embodiment, and can be carried out in various modes without departing from the gist of the invention. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above-described embodiments. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, the constituent elements of different embodiments may be combined appropriately. For the sake of easy understanding, the drawings mainly show the respective constituent elements, and the thickness, length, number, interval, etc. of the respective constituent elements shown in the drawings are not the actual ones for the sake of convenience of drawing. Is different. Further, the materials, shapes, dimensions, and the like of the respective constituent elements shown in the above-described embodiment are merely examples, and are not particularly limited, and various modifications can be made without substantially departing from the constitution of the present invention.

As described with reference to FIG. 1, the image forming apparatus 2 may be a printer, a fax machine, or a multifunction machine in which a printer, a fax machine, a scanner, and other information devices are combined. Since the image forming apparatus 2 includes the fixing device 12 described in the present embodiment, the influence of electric noise can be suppressed and the performance of the heat sensitive body can be prevented from being deteriorated. The temperature can be prevented.

INDUSTRIAL APPLICABILITY The present invention can be used in the fields of fixing devices and image forming apparatuses.

2 image forming device 4 reading unit 6 feeding unit 8 conveying unit 10 image forming unit 12 fixing device 14 discharging unit 16 fixing belt 18 pressing member 20 heating units 22, 22A, 22B belt holding member 24 core metal 26 elastic layer 28 separation Mold layer 30 Reinforcing member 32 Biasing member 34 Heater 36 Heater holding portions 38, 38A, 38B First heat sensitive body 40, 40A, 40B Second heat sensitive body 42, 42A, 42B Cover portion 44, 44A, 44B Cover portion 46 Cable 48 1st cable 50 Primary side power supply 52, 52A, 52B 2nd cable 54 Secondary side power supply 56 1st guide member 58 1st pressing part 60 2nd guide member 62 2nd pressing part 64 1st area 66 2nd area 68th 1 terminal 70 2nd terminal 72A, 72B 3rd terminal

Claims (8)

A fixing belt,
A heating unit facing the inner peripheral surface of the fixing belt,
The heating unit,
A heater for heating the fixing belt,
A first thermosensitive element facing the heater,
A second thermosensitive element facing the heater,
A first cable connected to the first heat sensitive body;
A second cable connected to the second heat sensitive body,
The first heat sensitive body is connected to a primary side power source by the first cable,
The second heat sensitive body is connected to a secondary side power source by the second cable,
A fixing device in which a first area in which the first cable is arranged and a second area in which the second cable is arranged are different from each other. The first heat sensitive body and the second heat sensitive body are arranged along a predetermined direction,
The first heat sensitive body is disposed closer to the primary power source than the secondary power source,
The fixing device according to claim 1, wherein the second heat sensitive body is disposed closer to the secondary power source than the primary power source. The fixing device according to claim 2, wherein the extending direction of the first cable is opposite to the extending direction of the second cable. The heating unit,
A first cover portion for holding the first heat sensitive body and the first cable;
A second cover portion that holds the second heat sensitive body and the second cable;
The first cover portion and the second cover portion are arranged along the predetermined direction,
The first cover portion has a first guide member that guides the first cable toward the primary-side power supply,
The fixing device according to claim 3, wherein the second cover portion includes a second guide member that guides the second cable toward the secondary power source. The first heat sensitive body includes a thermocut or a thermostat,
The second heat sensitive body includes a thermistor,
The thermocut, when the temperature of the heater is equal to or higher than a threshold value, shuts off the supply of electric power to the heater,
The thermostat interrupts the supply of the electric power to the heater when the temperature of the heater is equal to or higher than the threshold value, and restores the supply of the electric power to the heater when the temperature of the heater is lower than the threshold value. Let
The fixing device according to any one of claims 1 to 4, wherein the thermistor measures the temperature of the heater. The fixing device according to claim 1, wherein a voltage of electric power supplied by the primary power supply is higher than a voltage of electric power supplied by the secondary power supply. The fixing device according to claim 1, wherein a diameter of the first cable is larger than a diameter of the second cable. A fixing device according to any one of claims 1 to 7;
An image forming unit for forming a toner image on the sheet,
The image forming apparatus, wherein the fixing device fixes the toner image on the sheet.

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