CN113196869B - Heater and fixing device - Google Patents
Heater and fixing device Download PDFInfo
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- CN113196869B CN113196869B CN201980083937.0A CN201980083937A CN113196869B CN 113196869 B CN113196869 B CN 113196869B CN 201980083937 A CN201980083937 A CN 201980083937A CN 113196869 B CN113196869 B CN 113196869B
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Classifications
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G15/00—Apparatus for electrographic processes using a charge pattern
- G03G15/20—Apparatus for electrographic processes using a charge pattern for fixing, e.g. by using heat
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B3/00—Ohmic-resistance heating
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B3/00—Ohmic-resistance heating
- H05B3/02—Details
- H05B3/03—Electrodes
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B3/00—Ohmic-resistance heating
- H05B3/10—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor
- H05B3/12—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B3/00—Ohmic-resistance heating
- H05B3/10—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor
- H05B3/16—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor the conductor being mounted on an insulating base
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Resistance Heating (AREA)
- Fixing For Electrophotography (AREA)
- Electrophotography Configuration And Component (AREA)
- Control Of Resistance Heating (AREA)
Abstract
The heater is provided with: a substrate extending from a 1 st end to a 2 nd end; a plurality of terminals located on the 1 st end side or the 2 nd end side in the longitudinal direction of the substrate; and a heat generating unit group having a plurality of heat generating units arranged in a longitudinal direction of the substrate, the plurality of heat generating units being connected to the same terminal. In the heat generating portion group, the heat generating portion located at the center has a smaller resistance than the heat generating portion located at the end.
Description
Technical Field
Embodiments of the present disclosure relate to a heater and a fixing device.
Background
Conventionally, a fixing heater including a heat generating portion group in which a plurality of heat generating portions are arranged in an aligned manner and which generates heat by integrating the plurality of heat generating portions is known (for example, refer to patent document 1).
Prior art literature
Patent literature
Patent document 1: japanese patent laid-open publication 2016-115512
Disclosure of Invention
Problems to be solved by the invention
However, in the conventional fixing heater, since current concentration occurs in the central portion of the heat generating portion group, there is a problem in that temperature variation occurs in a plurality of heat generating portions in the heat generating portion group.
One embodiment of the present invention has been made in view of the above circumstances, and an object thereof is to provide a heater and a fixing device in which variations in temperature in a plurality of heat generating portions are small.
Means for solving the problems
A heater according to an embodiment includes: a substrate extending from a 1 st end to a 2 nd end; a plurality of terminals located on the 1 st end side or the 2 nd end side in the longitudinal direction of the substrate; and a heat generating unit group having a plurality of heat generating units arranged in a longitudinal direction of the substrate, the plurality of heat generating units being connected to the same terminal. In the heat generating portion group, the heat generating portion located at the center has a smaller resistance than the heat generating portion located at the end portion.
A fixing device according to an embodiment includes: a fixing member that heats toner on a medium while rotating around an axis; a pressing member that forms a pressing area between the fixing members while rotating around an axis, and presses toner on the medium passing through the pressing area; and a heater disposed in correspondence with the pressing area with the fixing member interposed therebetween, for heating the fixing member. The heater is provided with: a substrate extending from a 1 st end to a 2 nd end; a plurality of terminals located on the 1 st end side or the 2 nd end side in the longitudinal direction of the substrate; and a heat generating unit group having a plurality of heat generating units arranged in a longitudinal direction of the substrate, the plurality of heat generating units being connected to the same terminal. In the heat generating portion group, the heat generating portion located at the center has a smaller resistance than the heat generating portion located at the end portion.
Effects of the invention
In the heater and the fixing device according to one embodiment, the variation in temperature among the plurality of heat generating portions is small.
Drawings
Fig. 1 is a schematic diagram (front view) showing a printer according to the embodiment.
Fig. 2 is a cross-sectional view schematically showing a fixing device according to an embodiment.
Fig. 3 is a bottom view schematically showing a heater according to an embodiment.
Fig. 4 is a cross-sectional view taken along line A-A of fig. 3.
Fig. 5 is a diagram for explaining a factor of temperature deviation in the heater according to the embodiment.
Fig. 6 is a diagram for explaining an example of arrangement of a resistance heating element in the heater according to the embodiment.
Fig. 7 is a bottom view schematically showing a heater according to modification 1 of the embodiment.
Fig. 8 is a diagram for explaining the cause of temperature variation in the heater according to modification 1 of the embodiment.
Fig. 9 is a bottom view schematically showing a heater according to modification 2 of the embodiment.
Detailed Description
Embodiments of a heater and a fixing device disclosed in the present application will be described below with reference to the drawings. In addition, "Fr" shown in each figure means "front", "Rr" means "rear", "L" means "left", "R" means "right", "U" means "up", "D" means "down".
[ Integrated Structure of Printer ]
First, the overall configuration of the printer 1 using the fixing device 7 according to the embodiment will be described with reference to fig. 1. Fig. 1 is a schematic diagram (front view) showing a printer 1. The printer 1 includes a device main body 2, a paper feed cassette 3, a paper discharge tray 4, a paper feed device 5, an image forming device 6, a fixing device 7, and a control device not shown.
The apparatus main body 2 has a substantially rectangular parallelepiped shape in the printer 1. The sheet cassette 3 is located at a lower portion of the apparatus main body 2, and accommodates a sheet S before an image is formed thereon. Such a sheet S is an example of a medium, for example, plain paper. The sheet S is not limited to paper, and may be made of resin or the like.
The sheet discharge tray 4 is located at an upper portion of the apparatus main body 2, and accommodates sheets S on which images are formed. The sheet feeding device 5 is located at an upstream end portion of a conveyance path 8 extending from the sheet feeding cassette 3 to the sheet discharge tray 4.
The image forming apparatus 6 is located at the intermediate portion of the conveyance path 8, and has a toner container 10, a drum (drum) unit 11, and an optical scanning device 12.
The toner container 10 accommodates, for example, black toner (developer). The toner contained in the toner container 10 may be a two-component developer in which toner and carrier are mixed, or may be a one-component developer containing magnetic toner.
The drum unit 11 has a photosensitive drum 13, a charging device 14, a developing device 15, and a transfer roller 16. The transfer roller 16 contacts the photosensitive drum 13 from the lower side to form a transfer nip (nip).
The fixing device 7 is located on the downstream side of the conveyance path 8. Details of such a fixing device 7 will be described later.
The control device appropriately controls the above-described respective devices, and performs image forming processing in accordance with the following steps. First, the charging device 14 charges the surface of the photosensitive drum 13. Then, the photosensitive drum 13 receives the scanning light emitted from the light scanning device 12, and carries an electrostatic latent image.
Next, the developing device 15 develops the electrostatic latent image on the photosensitive drum 13 into a toner image using the toner supplied from the toner container 10. Then, the sheet feeding device 5 feeds the sheet S from the sheet feeding cassette 3 to the conveyance path 8. Thereby, the toner image on the photosensitive drum 13 is transferred onto the sheet S passing through the transfer nip.
Next, the fixing device 7 fixes the toner image to the sheet S. Finally, the sheet S to which the toner image is fixed is discharged to the discharge tray 4.
[ fixing device and heater ]
Next, details of the fixing device 7 and the heater 23 according to the embodiment will be described with reference to fig. 2 to 6. Fig. 2 is a cross-sectional view schematically showing the fixing device 7 according to the embodiment, fig. 3 is a bottom view schematically showing the heater 23 according to the embodiment, and fig. 4 is a cross-sectional view taken along line A-A shown in fig. 3.
As shown in fig. 2, the fixing device 7 includes a fixing belt 21, a pressure roller 22, and a heater 23. The fixing belt 21 is an example of a fixing member, the pressing roller 22 is an example of a pressing member, and the heater 23 is an example of a heater.
The fixing belt 21 is an endless belt, and is substantially cylindrical long in the front-rear direction (hereinafter also referred to as the axial direction). The surface layer of the fixing belt 21 includes, for example, a synthetic resin material having heat resistance and elasticity such as polyimide resin.
The fixing belt 21 is disposed above the inside of the casing 20 (see fig. 1). A pair of substantially cylindrical covers (not shown) are attached to both axial end portions of the fixing belt 21. Further, a belt guide (not shown) for holding the fixing belt 21 in a substantially cylindrical shape may be located inside the fixing belt 21.
The pressing member 24 is located inside the fixing belt 21. The pressing member 24 is substantially square tubular and long in the axial direction. The pressing member 24 penetrates the fixing belt 21 (and the cover) in the axial direction and is supported by the case 20. The fixing belt 21 is rotatably supported with respect to the pressing member 24. The pressing member 24 is made of, for example, a metal material.
The pressing roller 22 is substantially cylindrical and long in the front-rear direction (i.e., the axial direction). The pressing roller 22 is disposed below the inside of the casing 20. The pressing roller 22 includes a metal core 22a and an elastic layer 22b such as silicone sponge laminated on the outer peripheral surface thereof.
Both axial end portions of the core 22a are rotatably supported by the housing 20. A drive motor (not shown) is connected to the core 22a via a gear train or the like, and the pressure roller 22 is rotationally driven by the drive motor.
The fixing device 7 further includes a pressure adjusting portion (not shown) for raising and lowering the pressure roller 22 to adjust the contact pressure of the pressure roller 22 with respect to the fixing belt 21. By pressing the pressing roller 22 against the fixing belt 21, a pressing area N is formed between the fixing belt 21 and the pressing roller 22.
The pressing region N is a region from a position on the upstream side in the conveying direction of the sheet S having a pressure of 0Pa to a position on the downstream side in the conveying direction of the sheet S having a pressure of 0Pa again via a position that becomes the maximum pressure.
In the present disclosure, the "passing direction" refers to a direction orthogonal to the axial direction and a direction (a direction in which the sheet S is conveyed) in which the sheet S passes through the pressing area N of the fixing device 7. In the following description, "upstream" and "downstream" and terms similar to these refer to "upstream" and "downstream" in the passing direction and concepts similar to these.
The heater 23 is a heat source for heating the fixing belt 21. The heater 23 is fixed to the lower surface of the pressing member 24 via the holding member 25. The holding member 25 has a semicircular cross section perpendicular to the axial direction and is long in the axial direction. Along the lower inner surface of the fixing belt 21. The holding member 25 is made of, for example, a heat-resistant resin material.
As shown in fig. 4, the heater 23 includes a substrate 30, a heat insulating layer 31, and a heat generating contact portion 32. The base plate 30 is fixed to the lower surface of the holding member 25. The heat insulating layer 31 is located on the lower surface of the substrate 30. The heat generating contact portion 32 is located on the lower surface of the heat insulating layer 31.
The heater 23 is held on the lower surface of the holding member 25. The heat generating contact portion 32 of the heater 23 is a portion that is in contact with the inner surface of the fixing belt 21, and is opposed to the pressure roller 22. Further, the contact portion of the fixing belt 21 and the pressing roller 22 is a pressing area N.
That is, the heater 23 is provided in correspondence with the pressing region N with the fixing belt 21 interposed therebetween. A temperature sensor (not shown) for detecting the surface temperature of the fixing belt 21 or the temperature of the heater 23 may be provided in the case 20 shown in fig. 1.
As shown in fig. 3 and 4, the substrate 30 is substantially rectangular plate-shaped long in the front-rear direction (axial direction). In other words, the axial direction of the substrate 30 is the long side direction, and the passing direction is the short side direction, and extends from the 1 st end 30a to the 2 nd end 30b in the long side direction. The substrate 30 is made of a material having electrical insulation such as ceramic.
Here, the 1 st end 30a of the substrate 30 is an end portion on the side from which the individual electrodes 51 to 53 described later are led out, and the 2 nd end 30b is an end portion on the opposite side from the 1 st end 30 a. The upper and lower surfaces of the substrate 30 are substantially smooth.
The heat insulating layer 31 is laminated (film-formed) on one surface (the entire lower surface) of the substrate 30. The heat insulating layer 31 is made of a material having electrical insulation and low thermal conductivity, such as ceramic or glass. The heat insulating layer 31 has a function of restricting heat generated at the heat generating contact portion 32 from being transferred to the substrate 30 side.
The heat generating contact portion 32 is laminated on one face (lower face) of the heat insulating layer 31. As shown in fig. 3, the heat generating contact portion 32 includes a plurality of (for example, three) heat generating portion groups 41, the same number of individual electrodes 51 to 53 as those of the heat generating portion groups 41, a common electrode 54, and a coating layer 60 (see fig. 4).
The plurality of heat generating portion groups 41 include, for example, a conductive material such as a metal having a larger resistance than the individual electrodes 51 to 53 and the common electrode 54. The plurality of heat generating portion groups 41 are arranged in a row on the lower surface of the heat insulating layer 31 in the longitudinal direction of the substrate 30.
Each heat generating unit group 41 includes a plurality of resistance heat generating elements 40 arranged in a row in the longitudinal direction of substrate 30. The resistance heating element 40 is an example of a heating portion. Each of the plurality of resistive heating elements 40 has a substantially rectangular shape elongated in the passing direction (i.e., the short side direction of the substrate 30).
The plurality of heat generating portion groups 41 include a 1 st heat generating portion group 41A, a 2 nd heat generating portion group 41B, and a 3 rd heat generating portion group 41C in this order from the 1 st end 30a side of the substrate 30. That is, the 2 nd heat generating portion group 41B is located at the center in the axial direction, the 1 st heat generating portion group 41A is located on the 1 st end 30a side in the axial direction, and the 3 rd heat generating portion group 41C is located on the 2 nd end 30B side in the axial direction.
The 2 nd heat generating portion group 41B located at the center in the axial direction includes a plurality of (eight in the drawing) resistance heat generating elements 40 arranged in a range corresponding to the front-rear width of the sheet S of a small size (for example, A5 size) passing through the pressurizing region N.
The 1 st heat generating unit group 41A and the 3 rd heat generating unit group 41C located on both sides of the 2 nd heat generating unit group 41B include a plurality of (four in the drawing) resistance heat generating units 40 arranged in a range corresponding to the front-rear width of the sheet S of a normal size (for example, A4 size) passing through the pressurizing area N.
Here, in the embodiment, the 2 nd heat generating portion group 41B located at the center in the axial direction has more resistance heat generating elements 40 than the 1 st heat generating portion group 41A and the 3 rd heat generating portion group 41C located at both sides in the axial direction.
A plurality of individual electrodes 51 to 53 and a common electrode 54 are located on the lower surface of the heat insulating layer 31. The plurality of individual electrodes 51 to 53 and the common electrode 54 are made of a conductive material such as a metal having a smaller resistance than the resistance heating element 40.
The individual electrode 51 connects one side of the 1 st heat generating unit group 41A to the terminal 61. The individual electrode 52 connects one side of the 2 nd heat generating portion group 41B to the terminal 62. The individual electrode 53 connects one side of the 3 rd heat generating portion group 41C to the terminal 63.
The common electrode 54 connects the other sides of all the heat generating portion groups 41 to the same terminal 64. The terminals 61 to 64 are connection terminals for electrically connecting to external devices such as a power supply.
The individual electrode 51 has a connection portion 51a and a lead portion 51b. The connection portion 51A is a portion connecting the resistive heating elements 40 of the 1 st heating element group 41A in parallel. The lead portion 51b extends from such a connection portion 51a toward the terminal 61 in the longitudinal direction of the substrate 30.
The individual electrode 52 has a connection portion 52a and a lead portion 52b. The connection portion 52a is a portion connecting the resistance heating elements 40 of the 2 nd heating element group 41B in parallel. The lead portion 52b extends from such a connection portion 52a toward the terminal 62 in the longitudinal direction of the substrate 30.
The individual electrode 53 has a connection portion 53a and a lead portion 53b. The connection portion 53a is a portion connecting the resistance heating elements 40 of the 3 rd heating element group 41C in parallel. The lead portion 53b extends from the connection portion 53a toward the terminal 63 in the longitudinal direction of the substrate 30.
The common electrode 54 has a connection portion 54a and a lead-out portion 54b. The connection portion 54a is a portion connecting the resistance heating elements 40 of all the heating element groups 41 in parallel. The lead portion 54b extends from such a connection portion 54a toward the terminal 64 in the longitudinal direction of the substrate 30.
As shown in fig. 4, the coating layer 60 covers the plurality of heat generating part groups 41, the plurality of individual electrodes 51 to 53, and the common electrode 54. The coating 60 contains a material such as ceramic that has electrical insulation and has a small sliding friction force with respect to the fixing belt 21.
The coating 60 constitutes a surface that contacts the inner surface of the fixing belt 21. The coating 60 is also laminated on a portion where the plurality of heat generating unit groups 41, the individual electrodes 51 to 53, and the common electrode 54 are not laminated.
In the production of the heater 23 described above, for example, a film formation technique such as sputtering, a production technique of a printed board, a screen printing technique, or a combination of these techniques can be used.
For example, the heat insulating layer 31 and the heat generating contact portion 32 may be formed on the substrate 30 by sputtering. The heat insulating layer 31 and the heat generating contact portion 32 may be formed on the substrate 30 by repeating the steps of exposure, development, etching, peeling, lamination, and the like using a photomask as a manufacturing technique of a printed circuit board.
The heat insulating layer 31 and the heat generating contact portion 32 may be formed by applying (screen printing) an electrically insulating paint or an electrically conductive paint to the substrate 30. In these methods, the heat insulating layer 31 and the heat generating contact portion 32 can be formed on the substrate 30 with high precision.
The terminals 61 to 64 of the heater 23, the drive motor, and the like are electrically connected to a power source (not shown) via various drive circuits (not shown). The heater 23, the drive motor, the temperature sensor, and the like are electrically connected to a control device of the printer 1 via various circuits. Such a control device controls the electrically connected devices and the like.
Here, details of the fixing process performed by the fixing device 7 will be described mainly with reference to fig. 2.
First, the control device drives and controls the drive motor and the heater 23. The pressure roller 22 is rotated by the driving force of the driving motor, and the fixing belt 21 is rotated by the pressure roller 22 (see the solid thin arrow in fig. 2).
Each of the resistance heating elements 40 (see fig. 3) generates heat by passing a current between the individual electrodes 51 to 53 (see fig. 3) and the common electrode 54 (see fig. 3) of the plurality of heating element groups 41 (see fig. 3) in the passing direction (i.e., the short side direction of the substrate 30). Thereby, the pressing area N of the fixing belt 21 is heated.
At this time, the control device changes the heat generating portion group 41 for generating heat according to the size of the sheet S. For example, when the sheet S of a normal size passes through the pressing area N, the control device supplies electric power to all the heat generating portion groups 41, and causes all the heat generating portion groups 41 to generate heat.
When the small-sized sheet S passes through the pressing area N, the control device causes only the central 2 nd heat generating portion group 41B (see fig. 3) to generate heat. Thereby, only a necessary portion of the fixing belt 21 (pressing region N) can be heated in accordance with the size of the sheet S. As a result, excessive temperature rise at both axial end portions of the fixing belt 21 can be suppressed.
The temperature sensor detects the surface temperature of the fixing belt 21, and sends a detection signal to the control device via the input circuit. When receiving a detection signal indicating that the set temperature (for example, 150 to 200 ℃) is reached from the temperature sensor, the control device starts the image forming process described above while controlling the heater 23 so as to maintain the set temperature.
The sheet S to which the toner image is transferred enters the casing 20, and the fixing belt 21 heats the toner (toner image) on the sheet S passing through the pressing area N while rotating around the shaft in the forward direction. The pressing roller 22 presses the toner on the sheet S passing through the pressing area N while rotating around the shaft. Then, the toner image is fixed on the sheet S. Then, the sheet S to which the toner image is fixed is sent out of the casing 20 (see fig. 1) and discharged to the discharge tray 4 (see fig. 1).
Fig. 5 is a diagram for explaining a factor of temperature deviation in the heater 23 according to the embodiment. In the heater 23 having the above-described configuration, as shown in fig. 5, in one heat generating portion group 41, the current is concentrated in the central portion of the heat generating portion group 41. Thus, the current flowing through the lead-out portion 52b increases, and the wiring resistance of the lead-out portion 52b increases.
Thus, the resistance heating element 40 located at the center of the heat generating unit group 41 is cooled to a lower temperature than the resistance heating element 40 located at the end. This is because the wiring resistance of the lead-out portion 52b increases, and the voltage supplied to the resistive heating element 40 located in the central portion decreases due to the wiring loss of the lead-out portion 52 b.
Q＝V 2 /R·t (1)
Q＝I 2 ·R·t (2)
In the above equation (1), V is a voltage value, R is a resistance, and t is a time for which a current flows. In the above equation (2), I is a current value.
In particular, in the heat generating unit group 41 (the 2 nd heat generating unit group 41B) having the largest number of resistance heat generating units 40, since the concentration degree of the current to the central portion is larger than that of the other heat generating unit groups 41 (the 1 st heat generating unit group 41A and the 3 rd heat generating unit group 41C), the wiring loss of the lead-out portion 52B becomes large, the voltage supplied to the central portion becomes smaller than the end portion, and the central portion is further cooled.
In this way, when the temperature of the resistance heating element 40 located in the central portion of the heating element group 41 is lowered, a temperature deviation occurs in the longitudinal direction in the heater 23, and thus there is a possibility that an adverse effect may be exerted on fixing of the toner image to the sheet S.
Therefore, in the embodiment, in the same heat generating unit group 41, the resistance of the resistance heat generating element 40 located at the center is made smaller than the resistance of the resistance heat generating element 40 located at the end. As a result, the current supplied to the resistance heating element 40 located at the center increases, and the joule heat Q of the resistance heating element 40 located at the center increases as shown in the above equation (2). On the other hand, although the current flowing to the lead-out portion 52b increases, the wiring loss of the lead-out portion 52b increases, but the influence of the wiring loss of the lead-out portion 52b on the increase in joule heat Q decreases, and the joule heat Q of the resistance heating element 40 located at the end portion can be approximated.
Therefore, according to the embodiment, the variation in temperature of the plurality of resistance heating elements 40 in the heater 23 is small.
Specifically, in the case of the 2 nd heat generating unit group 41B having a large concentration of current to the central portion, the resistance of the resistance heat generating element 40 located at the central portion is preferably made smaller than the resistance of the resistance heat generating element 40 located at the end portion by a predetermined ratio, for example, 10%.
The resistance of the resistance heating element 40 located between the center portion and the end portion may be adjusted stepwise according to the distance from the center portion and the end portion of the resistance heating element 40. This can effectively reduce the variation in temperature in the 2 nd heat generating unit group 41B.
Even in the case of the heat generating unit group 41 (the 1 st heat generating unit group 41A, the 3 rd heat generating unit group 41C) in which the number of the resistance heat generating units 40 is small and the concentration degree of the current to the central portion is small, the resistance of the resistance heat generating unit 40 located at the central portion may be made smaller than the resistance of the resistance heat generating unit 40 located at the end portion. This effectively limits the variation in temperature in the heat generating unit groups 41 (the 1 st heat generating unit group 41A and the 3 rd heat generating unit group 41C).
In the heater 23 having the above-described configuration, as shown in fig. 5, more current flows through the individual electrode 52 of the 2 nd heat generating unit group 41B having the largest number of resistance heat generating elements 40 than through the other individual electrodes 51 and 53. This is because, in order to generate heat in the entire large number of resistive heating elements 40, a large amount of current must be applied to the individual electrodes 52 in response to this.
In such an individual electrode 52, the lead portion 52b is narrower than the connection portion 52a, and therefore, the resistance per unit length is large. This is because, since the width of the heater 23 in the short side direction of the substrate 30 (i.e., the passing direction of the sheet S) is limited, it is difficult to widen the width of the plurality of drawing portions 51b to 53b arranged in the short side direction.
Therefore, in the heater 23 having the above-described configuration, when a large amount of current flows through the lead portion 52b of the individual electrode 52, heat is generated in such lead portion 52 b.
When the lead portion 52b generates heat, the temperature of the heat generating portion group 41 (1 st heat generating portion group 41A) adjacent to the lead portion 52b is higher than the temperature of the other heat generating portion group 41 due to thermal interference, and therefore, a temperature deviation occurs in the longitudinal direction in the heater 23.
Therefore, in the embodiment, the resistance of the resistance heat generating element 40 of the heat generating unit group 41 (the 1 st heat generating unit group 41A) adjacent to the heat generating unit 52B is made larger than the resistance heat generating elements 40 of the other heat generating unit groups 41 (the 2 nd heat generating unit group 41B, the 3 rd heat generating unit group 41C). Here, the resistive heating element 40 adjacent to the lead portion 52b is the resistive heating element 40 located directly below the lead portion 52b in the illustrated surface, and is the resistive heating element 40 located in the 1 st heat generating portion group 41A according to fig. 5.
In other words, the resistance of the heat generating unit group 41 of the 2 nd heat generating unit group 41B, which maximizes the number of resistance heat generating units 40, is larger than that of the heat generating unit group 41 of the opposite side (i.e., the 2 nd end 30B side) by the heat generating unit group 41 led out to one side (i.e., the 1 st end 30a side) of the terminal 62.
Accordingly, the current supplied to the resistance heating element 40 adjacent to the lead portion 52b decreases, and the joule heat Q of the resistance heating element 40 adjacent to the lead portion 52b decreases as shown in the above equation (2). This makes it possible to bring the total of the joule heat Q of the resistance heat generating element 40 adjacent to the lead-out portion 52b and the heat generated from the lead-out portion 52b close to the joule heat Q of the other resistance heat generating element 40. Therefore, according to the embodiment, the variation in temperature among the plurality of resistance heating elements 40 in the heater 23 can be reduced.
For example, the resistance of the resistance heating element 40 at the 1 st end 30a side is preferably smaller than the resistance of the resistance heating element 40 at the 2 nd end 30b side by a predetermined ratio (for example, 35%).
The resistance of the resistance heating element 40 located between the 1 st end 30a side and the 2 nd end 30b side may be adjusted stepwise according to the distance from the resistance heating element 40 on the 1 st end 30a side and the 2 nd end 30b side. This can effectively reduce the variation in temperature among the plurality of heat generating unit groups 41.
In the embodiment, as a method of making the resistance of the specific resistance heating element 40 smaller than the resistance of the other resistance heating elements 40, the length of the specific resistance heating element 40 may be made shorter than the other resistance heating elements 40, or the cross-sectional area (i.e., width×thickness) may be made larger. In addition, the specific resistance heating element 40 may be made of a material having a smaller resistance than the other resistance heating elements 40.
For example, when the length of a specific resistance heat generating element 40 is made shorter than that of other resistance heat generating elements 40, the centers of the resistance heat generating elements 40 provided in the heater 23 are preferably aligned along the longitudinal direction of the substrate 30 (i.e., aligned along the center in the longitudinal direction of the center). This makes it possible to make the temperature distribution of the heater 23 nearly uniform in the direction of passing the sheet S (i.e., the short side direction of the substrate 30). The resistive heating elements 40 may be arranged so as to be aligned in the longitudinal direction, and the centers of all the resistive heating elements may not be aligned, but at least 80% of the entire resistive heating elements may be aligned. Further, the center of the resistance heat generating element 40 may be a planar photograph, and the area center of gravity of the resistance heat generating element 40 may be obtained by image processing.
In addition, when the length of the resistance heat generating element 40 (simply referred to as the resistance heat generating element 40 a) adjacent to the lead-out portion 52b of the independent electrode 52 is made shorter than that of the other resistance heat generating elements 40 (simply referred to as the resistance heat generating element 40 b.), as shown in fig. 6, the resistance heat generating element 40a adjacent to the lead-out portion 52b may be arranged farther from the lead-out portion 52b of the independent electrode 52 than the other resistance heat generating elements 40b. Fig. 6 is a diagram for explaining an example of arrangement of the resistance heating element 40 in the heater 23 according to the embodiment. Here, the drawing portion 52b in which the resistance heating element 40a adjacent to the drawing portion 52b is farther from the individual electrode 52 than the other resistance heating elements 40b is a comparison of the distance from the resistance heating element 40 in the short side direction of the substrate 30 when the drawing portion 52b is present in the long side direction of the substrate 30.
Thus, the lead portion 52b is distant from the resistance heating element 40a adjacent to the lead portion 52 b. In other words, the line connecting the centers of the resistance heating elements 40a is closer to the common electrode 54 than the line connecting the centers of the other resistance heating elements 40 b. Thereby, the heat generating region of the resistance heat generating element 40a constituting the 1 st heat generating unit group 41A becomes close to the common electrode 54 side. As a result, in the temperature distribution on the line connecting the centers of the resistive heating elements 40a (in other words, the temperature distribution on the pressing region N in fig. 2), the temperature distribution of the heater 23 in the short side direction of the substrate 30 (i.e., the passing direction of the sheet S) can be made nearly uniform.
In the embodiment, all of the terminals 61 to 64 to which the plurality of individual electrodes 51 to 53 and the common electrode 54 are connected are arranged on the 1 st end 30a side of the substrate 30. This can reduce the width of the heater 23 in the longitudinal direction, and thus can miniaturize the heater 23.
[ various modifications ]
Next, various modifications of the heater 23 will be described with reference to fig. 7 to 9. Fig. 7 is a bottom view schematically showing a heater 23 according to modification 1 of the embodiment. Fig. 8 is a diagram for explaining a factor of temperature variation in the heater 23 according to modification 1 of the embodiment. In the following description, the same parts as those in the above-described embodiment are denoted by the same reference numerals, and overlapping description thereof is omitted.
The modification 1 shown in fig. 7 is different from the embodiment in that the lead portions 53b and 54b of the individual electrode 53 and the common electrode 54 extend not toward the 1 st end 30a side but toward the 2 nd end 30b side of the substrate 30. The lead portions 51b and 52b of the individual electrodes 51 and 52 extend toward the 1 st end 30a of the substrate 30 as in the embodiment.
In this way, by the configuration in which the individual electrodes 51, 52 extend toward the 1 st end 30a side and the individual electrode 53 and the common electrode 54 extend toward the 2 nd end 30b side on both end sides in the longitudinal direction of the substrate 30, specifically, the space on both sides in the longitudinal direction of the heater 23 can be efficiently utilized.
On the other hand, as shown in fig. 8, in the heater 23 according to modification 1, as in the embodiment, the current is concentrated in the central portion of the heat generating unit group 41 in one heat generating unit group 41.
As a result, the resistance heating element 40 located at the center of the heat generating unit group 41 is cooled to a lower temperature than the resistance heating element 40 located at the end portion as described above.
Therefore, in modification 1, as in the embodiment, the resistance of the resistance heating element 40 located at the center is made smaller than the resistance of the resistance heating element 40 located at the end in the same heat generating unit group 41.
As a result, the current supplied to the resistance heating element 40 located at the center increases, and the joule heat Q of the resistance heating element 40 located at the center increases as shown in the above equation (2). On the other hand, although the current flowing to the lead-out portion 52b increases, the wiring loss of the lead-out portion 52b increases, but the influence of the wiring loss of the lead-out portion 52b on the increase in joule heat Q decreases, and the joule heat Q of the resistance heating element 40 located at the end portion can be approximated. Therefore, according to modification 1, the variation in temperature among the plurality of resistance heating elements 40 in the heater 23 can be reduced.
In the heater 23 according to modification 1, as in the embodiment, a larger amount of current flows through the individual electrode 52 of the 2 nd heat generating unit group 41B having the largest number of heat generating units 41 than through the other individual electrodes 51 and 53. Thereby, heat is generated at the lead portion 52b of the individual electrode 52.
Therefore, in modification 1, the resistance of the heat generating portion group 41 on the 1 st end 30a side is increased. Here, the 1 st heat generating portion group 41A, the 2 nd heat generating portion group 41B, and the 3 rd heat generating portion group 41C are arranged in this order from the 1 st end 30a side of the substrate 30. The 1 st heat generating unit group 41A is connected to the individual electrode 51, the 2 nd heat generating unit group 41B is connected to the individual electrode 52, and the 3 rd heat generating unit group 41C is connected to the individual electrode 53. Thus, in other words, the resistance of the 1 st heat generating unit group 41A is increased for the above description.
As a result, the current supplied to the resistance heating element 40 adjacent to the lead portion 52b decreases, and the joule heat Q of the resistance heating element 40 adjacent to the lead portion 52b decreases as shown in the above equation (2). This makes it possible to bring the total of the joule heat Q of the resistance heat generating element 40 adjacent to the lead-out portion 52b and the heat generated from the lead-out portion 52b close to the joule heat Q of the other resistance heat generating element 40. Therefore, according to modification 1, the variation in temperature among the plurality of resistance heating elements 40 in the heater 23 can be reduced.
Further, in modification 1, as shown in fig. 8, there is a limitation on the length (distance in the axial direction) of the lead portion 53b of the individual electrode 53 extending from the 3 rd heat generating portion group 41C toward the 2 nd end 30b side. Therefore, in modification 1, in the 3 rd heat generating unit group 41C to which the individual electrodes 53 are connected, the resistance of the resistance heat generating element 40 on the 2 nd end 30b side is made larger than the resistance of the resistance heat generating element 40 on the 1 st end 30a side.
Thus, even when the length of the lead portion 53b of the individual electrode 53 is limited, the variation in temperature among the plurality of resistance heating elements 40 in the heater 23 can be reduced.
Fig. 9 is a bottom view schematically showing a heater 23 according to modification 2 of the embodiment. The heater 23 shown in fig. 9 is different from the above-described embodiment in the point where the individual electrodes 51 to 53 and the common electrode 54 are connected to the resistance heating element 40.
Specifically, the connection portion 51a of the individual electrode 51 has a protruding portion 51a1 protruding in a comb-tooth shape in the short side direction of the substrate 30 toward the common electrode 54. The connection portion 52a of the individual electrode 52 has a protruding portion 52a1 protruding in a comb-tooth shape in the short side direction of the substrate 30 toward the common electrode 54.
The connection portion 53a of the individual electrode 53 has a protruding portion 53a1 protruding in a comb-tooth shape in the short side direction of the substrate 30 toward the common electrode 54. The connection portion 54a of the common electrode 54 has protruding portions 54a1 protruding in a comb-tooth shape in the short side direction of the substrate 30 toward the individual electrodes 51 to 53.
The resistance heating element 40 belonging to the 1 st heat generating unit group 41A is arranged between the protruding portion 51A1 and the protruding portion 54a1, the resistance heating element 40 belonging to the 2 nd heat generating unit group 41B is arranged between the protruding portion 52a1 and the protruding portion 54a1, and the resistance heating element 40 belonging to the 3 rd heat generating unit group 41C is arranged between the protruding portion 53a1 and the protruding portion 54a1.
All the resistance heating elements 40 are connected to the protruding portions 51a1 to 54a1 on both sides in the longitudinal direction of the substrate 30. That is, the current flowing through the resistive heating element 40 flows not in the short side direction of the substrate 30 but in the long side direction of the substrate 30 as in the above-described embodiment.
In the heater 23 according to modification 2 described above, as a method of making the resistance of the specific resistance heating element 40 smaller than the resistance of the other resistance heating elements 40, it is preferable that the distance between the protruding portions 51a1 to 54a1 connected to the specific resistance heating element 40 is smaller than the distance between the protruding portions 51a1 to 54a1 connected to the other resistance heating elements 40.
For example, in modification 2, in the same heat generating unit group 41, the interval between the protruding portions 51a1 to 54a1 connected to the resistance heating element 40 located at the center is made smaller than the interval between the protruding portions 51a1 to 54a1 connected to the resistance heating element 40 located at the end.
In this way, in the same heat generating unit group 41, the length of the resistance heat generating element 40 located at the center (here, the length along the longitudinal direction of the substrate 30) can be made shorter than the length of the resistance heat generating element 40 located at the end.
Therefore, in modification 2, as in the embodiment, the resistance of the resistance heating element 40 located at the center can be made smaller than the resistance of the resistance heating element 40 located at the end in the same heat generating unit group 41.
As shown in fig. 9, the distance between the protruding portions 51a1 to 54a1 connected to the resistance heating element 40 adjacent to the lead portion 52b of the independent electrode 52 is made narrower than the distance between the protruding portions 51a1 to 54a1 connected to the other resistance heating elements 40.
Thus, the length of the resistance heating element 40a adjacent to the lead portion 52b of the independent electrode 52 (here, the length along the longitudinal direction of the substrate 30) can be made shorter than the length of the other resistance heating element 40 b. Therefore, according to modification 2, the resistance of the resistance heating element 40a adjacent to the lead portion 52b of the independent electrode 52 can be made smaller than that of the other resistance heating elements 40 b.
In the heater 23 according to modification 2, the method of making the resistance of the specific resistance heating element 40 smaller than the resistance of the other resistance heating elements 40 is not limited to the case of narrowing the interval between the protruding portions 51a1 to 54a1 connected to the specific resistance heating element 40.
For example, the cross-sectional area (i.e., width×thickness) of a specific resistance heating element 40 may be larger than the cross-sectional area of other resistance heating elements 40. The term "width" as used herein refers to the length of the resistive heating element 40 along the short side direction of the substrate 30. Thus, the resistance of the specific resistance heating element 40 can be made smaller than the resistance of the other resistance heating elements 40.
In addition, the specific resistance heating element 40 may be made of a material having a smaller resistance than the other resistance heating elements 40. Thus, the resistance of the specific resistance heating element 40 can be made smaller than the resistance of the other resistance heating elements 40.
Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments, and various modifications are possible without departing from the gist thereof. For example, in the above-described embodiment, the example was shown in which eight resistance heat generating elements 40 are provided in the 2 nd heat generating unit group 41B, and four resistance heat generating elements 40 are provided in the 1 st heat generating unit group 41A and the 3 rd heat generating unit group 41C, but the number of resistance heat generating elements 40 provided in each heat generating unit group 41 is not limited to the above-described example.
In the above embodiment, the cross-sectional structure of the heater 23 is not limited to the example of fig. 4. For example, the individual electrodes 51 to 53 and the common electrode 54 may have a laminated structure including different metal materials (e.g., ag, al, etc.).
With such a laminated structure, the resistances of the individual electrodes 51 to 53 and the common electrode 54 can be reduced, and therefore the power consumption of the heater 23 can be reduced.
As described above, the heater (heater 23) according to the embodiment includes: a substrate 30 extending from a 1 st end 30a to a 2 nd end 30b; a plurality of terminals 61 to 63 located on the 1 st end 30a side or the 2 nd end 30b side in the longitudinal direction of the substrate 30; and a heat generating unit group 41 having a plurality of heat generating units (resistance heat generating units 40) arranged in a longitudinal direction of the substrate 30, the plurality of heat generating units (resistance heat generating units 40) being connected to the same terminals 61 to 63. In the heat generating unit group 41, the heat generating unit (resistance heat generating unit 40) located at the center has a smaller resistance than the heat generating unit (resistance heat generating unit 40) located at the end. Thus, even when the current is concentrated in the central portion of the heat generating unit group 41, the variation in temperature among the plurality of resistance heat generating elements 40 in the heater 23 can be reduced.
The heater (heater 23) according to the embodiment includes: a plurality of heat generating portion groups 41; a common electrode 54 connecting all the heat generating part groups 41 to the same terminal 64; and a plurality of individual electrodes 51 to 53 connecting the respective heat generating unit groups 41 to the same terminals 61 to 63. In addition, when the individual electrode 52 of the heat generating unit group 41 (the 2 nd heat generating unit group 41B) having the largest number of heat generating units (the resistance heat generating unit 40) is led out to the side of the terminal 62 as the 1 st end 30a side of the substrate 30, among the plurality of heat generating unit groups 41, the heat generating unit (the resistance heat generating unit 40) of the heat generating unit group 41 located on the 1 st end 30a side of the substrate 30 has a larger resistance than the heat generating unit (the resistance heat generating unit 40) of the heat generating unit group 41 located on the 2 nd end 30B side of the substrate 30. Thus, even when heat is generated from the lead portion 52b of the individual electrode 52, the variation in temperature among the plurality of resistance heating elements 40 in the heater 23 can be reduced.
In the heater (heater 23) according to the embodiment, all of the terminals 61 to 64 are located on the 1 st end 30a side of the substrate 30. This can reduce the width of the heater 23 in the longitudinal direction, and thus can miniaturize the heater 23.
In the heater (heater 23) according to the embodiment, the 1 st heat generating unit group 41A, the 2 nd heat generating unit group 41B, and the 3 rd heat generating unit group 41C are arranged in this order from the 1 st end 30a side of the substrate 30, the individual electrode 51 connected to the 1 st heat generating unit group 41A and the individual electrode 52 connected to the 2 nd heat generating unit group 41B are led out to the 1 st end 30a side of the substrate 30, and the individual electrode 53 and the common electrode 54 connected to the 3 rd heat generating unit group 41C are led out to the 2 nd end 30B side of the substrate 30. This makes it possible to efficiently use the space on both sides in the longitudinal direction of the heater 23.
In the heater (heater 23) according to the embodiment, in the 3 rd heat generating portion group 41C, the heat generating portion (resistance heat generating element 40) located on the 2 nd end 30b side of the substrate 30 has a larger resistance than the heat generating portion (resistance heat generating element 40) located on the 1 st end 30a side of the substrate 30. Thus, even when the length of the lead portion 53b of the individual electrode 53 is limited, the variation in temperature among the plurality of resistance heating elements 40 in the heater 23 can be reduced.
In the heater (heater 23) according to the embodiment, the resistance of the heat generating portion (resistance heat generating element 40) adjacent to the individual electrode 52 of the heat generating portion group 41 (2 nd heat generating portion group 41B) having the largest number of heat generating portions (resistance heat generating elements 40) is larger than that of the other heat generating portions (resistance heat generating elements 40). Thus, even when joule heat is generated from the lead portion 52b of the individual electrode 52, the variation in temperature among the plurality of resistance heating elements 40 in the heater 23 can be reduced.
In the heater (heater 23) according to the embodiment, the heat generating portion (resistance heat generating element 40) adjacent to the individual electrode 52 of the heat generating portion group 41 (2 nd heat generating portion group 41B) having the largest number of heat generating portions (resistance heat generating elements 40) is arranged farther from the individual electrode 52 than the other heat generating portions (resistance heat generating elements 40). This makes it possible to make the temperature distribution of the heater 23 in the passing direction of the sheet S nearly uniform.
In the heater (heater 23) according to the embodiment, the length of the heat generating portion (resistance heat generating element 40) having a small resistance is shorter than the length of the heat generating portion (resistance heat generating element 40) having a large resistance. Thus, even when the same material is used for all the resistance heating elements 40, the resistance heating elements 40 having different resistances can be configured.
In the heater (heater 23) according to the embodiment, the central portions (centers) of all the heat generating portions (resistance heat generating elements 40) are aligned in the longitudinal direction. This makes it possible to make the temperature distribution of the heater 23 uniform in the direction of passing the sheet S (i.e., the short side direction of the substrate 30).
In the heater (heater 23) according to the embodiment, the cross-sectional area of the heat generating portion (resistance heat generating element 40) having a small resistance is larger than the cross-sectional area of the heat generating portion (resistance heat generating element 40) having a large resistance. Thus, even when the same material is used for all the resistance heating elements 40, the resistance heating elements 40 having different resistances can be formed.
The fixing device 7 according to the embodiment includes: a fixing member (fixing belt 21) that heats the toner on the medium (sheet S) while rotating around an axis; a pressing member (pressing roller 22) that forms a pressing area N between the pressing member (fixing belt 21) and the fixing member (fixing belt 21) while rotating around a shaft, and presses toner on a medium (sheet S) passing through the pressing area N; and a heater (heater 23) disposed in correspondence with the pressing area N with the fixing member (fixing belt 21) interposed therebetween, for heating the fixing member (fixing belt 21). The heater (heater 23) further includes: a substrate 30 extending from a 1 st end 30a to a 2 nd end 30b; a plurality of terminals 61 to 63 located on the 1 st end 30a side or the 2 nd end 30b side in the longitudinal direction of the substrate 30; and a heat generating unit group 41 having a plurality of heat generating units (resistance heat generating units 40) arranged in a longitudinal direction of the substrate 30, the plurality of heat generating units (resistance heat generating units 40) being connected to the same terminals 61 to 63. In the heat generating unit group 41, the heat generating unit (resistance heat generating unit 40) located at the center has a smaller resistance than the heat generating unit (resistance heat generating unit 40) located at the end. This can realize the fixing device 7 in which the variation in temperature among the plurality of resistance heating elements 40 in the heater 23 is reduced.
The presently disclosed embodiments are considered in all respects to be illustrative and not restrictive. In practice, the above embodiments can be implemented in various ways. The above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope of the appended claims and their gist.
Symbol description
1: a printer;
7: a fixing device;
21: fixing belts (one example of a fixing member);
22: a pressing roller (an example of a pressing member);
23: a heater (an example of a heater);
30: a substrate;
30a: end 1;
30b: end 2;
31: a heat insulating layer;
32: a heat-generating contact portion;
40: a resistance heating element (an example of a heating portion);
41: a heat generating unit;
41A: a 1 st heating unit group;
41B: a 2 nd heating unit group;
41C: a 3 rd heating unit group;
51 to 53: an independent electrode;
54: a common electrode;
61 to 64: a terminal;
s: sheet (one example of a medium).
Claims (12)
1. A heater is provided with:
a substrate extending from a 1 st end to a 2 nd end;
a plurality of terminals located on the 1 st end side or the 2 nd end side in the longitudinal direction of the substrate;
a plurality of heat generating unit groups each having a plurality of heat generating units arranged in a longitudinal direction of the substrate, the plurality of heat generating units being connected to the same terminal;
A common electrode connecting all of the heat generating part groups to the same terminal; and
a plurality of independent electrodes connecting each of the heat generating part groups to the same terminal,
in the heat generating part group, the resistance of the heat generating part at the central part is smaller than that of the heat generating part at the end part,
in the case where the individual electrodes of the heat generating portion group having the largest number of heat generating portions are led out to one side of the terminal as the 1 st end side of the substrate,
among the plurality of heat generating portion groups, the heat generating portion of the heat generating portion group located on the 1 st end side of the substrate has a larger resistance than the heat generating portion of the heat generating portion group located on the 2 nd end side of the substrate.
2. The heater of claim 1, wherein,
all of the terminals are located on the 1 st end side of the substrate.
3. The heater of claim 1, wherein,
a 1 st heat generating unit group, a 2 nd heat generating unit group, and a 3 rd heat generating unit group are arranged in this order from the 1 st end side of the substrate,
the individual electrodes connected to the 1 st heat generating part group and the individual electrodes connected to the 2 nd heat generating part group are led out to the 1 st end side of the substrate,
The individual electrode and the common electrode connected to the 3 rd heat generating portion group are led out to the 2 nd end side of the substrate.
4. The heater according to claim 3, wherein,
in the 3 rd heat generating part group,
the resistance of the heat generating portion located on the 2 nd end side of the substrate is larger than that of the heat generating portion located on the 1 st end side of the substrate.
5. The heater as claimed in any one of claims 1 to 4, wherein,
the resistance of the heat generating portion adjacent to the individual electrode of the heat generating portion group having the largest number of heat generating portions is larger than that of the other heat generating portions.
6. The heater as claimed in any one of claims 1 to 4, wherein,
the heat generating portion adjacent to the individual electrode of the heat generating portion group having the largest number of heat generating portions is located farther from the individual electrode than the other heat generating portions.
7. The heater as claimed in any one of claims 1 to 4, wherein,
the length of the heat generating portion having a small resistance is shorter than the length of the heat generating portion having a large resistance.
8. The heater of claim 7, wherein,
the central portions of all the heat generating portions are aligned in the longitudinal direction.
9. The heater as claimed in any one of claims 1 to 4, wherein,
the cross-sectional area of the heat generating portion having a small resistance is larger than that of the heat generating portion having a large resistance.
10. The heater as claimed in any one of claims 1 to 4, wherein,
and a current flows through the heat generating portion along the short side direction of the substrate.
11. The heater as claimed in any one of claims 1 to 4, wherein,
and a current flows through the heat generating portion along the longitudinal direction of the substrate.
12. A fixing device is provided with:
a fixing member that heats toner on a medium while rotating around an axis;
a pressing member that forms a pressing area between the pressing member and the fixing member while rotating around an axis, and presses toner on the medium passing through the pressing area; and
a heater disposed in correspondence with the pressurizing region via the fixing member, for heating the fixing member,
the heater is provided with:
a substrate extending from a 1 st end to a 2 nd end;
a plurality of terminals located on the 1 st end side or the 2 nd end side in the longitudinal direction of the substrate;
a plurality of heat generating unit groups each having a plurality of heat generating units arranged in a longitudinal direction of the substrate, the plurality of heat generating units being connected to the same terminal;
A common electrode connecting all of the heat generating part groups to the same terminal; and
a plurality of independent electrodes connecting each of the heat generating part groups to the same terminal,
in the heat generating part group, the resistance of the heat generating part at the central part is smaller than that of the heat generating part at the end part,
in the case where the individual electrodes of the heat generating portion group having the largest number of heat generating portions are led out to one side of the terminal as the 1 st end side of the substrate,
among the plurality of heat generating portion groups, the heat generating portion of the heat generating portion group located on the 1 st end side of the substrate has a larger resistance than the heat generating portion of the heat generating portion group located on the 2 nd end side of the substrate.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2018-246307 | 2018-12-27 | ||
| JP2018246307 | 2018-12-27 | ||
| PCT/JP2019/050680 WO2020138105A1 (en) | 2018-12-27 | 2019-12-24 | Heater and fixing device |
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| Publication Number | Publication Date |
|---|---|
| CN113196869A CN113196869A (en) | 2021-07-30 |
| CN113196869B true CN113196869B (en) | 2023-06-30 |
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| CN201980083937.0A Active CN113196869B (en) | 2018-12-27 | 2019-12-24 | Heater and fixing device |
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| JP (1) | JP7092892B2 (en) |
| CN (1) | CN113196869B (en) |
| WO (1) | WO2020138105A1 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0529067A (en) * | 1991-07-25 | 1993-02-05 | Rohm Co Ltd | Structure of heating element and heater for office automation equipment |
| US7853165B2 (en) | 2008-12-04 | 2010-12-14 | Xerox Corporation | Apparatus and method for a multi-tap series resistance heating element in a belt fuser |
| EP2977824A1 (en) * | 2014-07-24 | 2016-01-27 | Canon Kabushiki Kaisha | Heater and image heating apparatus including the same |
| JP2016062024A (en) * | 2014-09-19 | 2016-04-25 | キヤノン株式会社 | Heater and fixing device |
| JP6666029B2 (en) * | 2015-11-24 | 2020-03-13 | キヤノン株式会社 | Heater and fixing device |
| JP6884032B2 (en) | 2016-06-20 | 2021-06-09 | 東芝テック株式会社 | Heater, heating device |
| JP2018146822A (en) * | 2017-03-07 | 2018-09-20 | キヤノンファインテックニスカ株式会社 | Heat generating device, image heating device, and image forming apparatus |
| JP2019012173A (en) | 2017-06-30 | 2019-01-24 | キヤノン株式会社 | Heater and fixation device |
-
2019
- 2019-12-24 CN CN201980083937.0A patent/CN113196869B/en active Active
- 2019-12-24 JP JP2020563319A patent/JP7092892B2/en active Active
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| JP7092892B2 (en) | 2022-06-28 |
| CN113196869A (en) | 2021-07-30 |
| JPWO2020138105A1 (en) | 2021-10-21 |
| WO2020138105A1 (en) | 2020-07-02 |
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