Heating device and heat treatment system using same

Abstract

The invention provides a heating device and a heat treatment system using the same. A heating device is provided with: a member to be heated; a heat generating member; a pressing member; and a pressure adjustment member that adjusts a pressure state such that the width of the contact region in the short-side direction changes, the heat generation member having a plurality of heat generation resistors extending in the long-side direction, and a high heat generation portion having a narrow width and a high heat generation amount and a low heat generation portion having a wide width and a low heat generation amount being formed by connecting the plurality of heat generation resistors. For at least two heating resistors among the plurality of heating resistors, a high-heat-generation portion is formed in a minimum contact region where the width of the contact region in the short-side direction is the smallest, among different regions of the contact region in the long-side direction, and when the minimum contact region where the width of the contact region in the short-side direction is the smallest is formed by the pressing member, the high-heat-generation portion is formed in the at least two heating resistors. Each of the high heat-generating portions is included within the range of the minimum contact region, a portion of the low heat-generating portion is included within the range of the minimum contact region, and the remaining portion of the low heat-generating portion exceeds the range of the minimum contact region.

Description

Technical Field

[0001] The present invention relates to a heating device and a heating treatment system using the heating device. Background Art

[0002] As a conventional heating device, for example, a heating device described in Patent Document 1 is provided.

[0003] In patent document 1, a fixing device is disclosed, which comprises: a cylindrical belt; a heater having a first heating resistor and a second heating resistor formed along the long side direction of an elongated substrate and in contact with the inner surface of the belt; and a supporting roller, which together with the heater forms a clamping portion for conveying and heating a recording material carrying a colorant image across the belt, wherein the resistance value per unit length of the first heating resistor at the end portion in the long side direction of the substrate is lower than that of the central portion, and the device comprises a first fixing processing mode in which both the first heating resistor and the second heating resistor enter a contact area between the heater and the belt, and a second fixing processing mode in which both the first heating resistor enters the contact area in the conveying direction of the recording material and at least a portion of the second heating resistor exceeds the contact area.

[0004] Patent Document 1: Japanese Patent No. 5618771 (Specific Implementation Method, Figure 4 ) Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a heating device and a heating treatment system using the heating device, in which, when a heating contact area is formed between a strip-shaped heated component and a heat-generating component, an excessive increase in temperature around the contact area is suppressed without increasing the pressure load on the contact area.

[0006] The first technical feature of the present invention is a heating device, characterized in that it comprises: a belt-shaped heated member that rotates cyclically; a heating member that is arranged in contact with the back side of the heated member, extends along a cross direction that intersects with the rotation direction of the heated member and heats the heated member; a pressurizing member that makes the heated member and the heating member contact each other under a pressurized state, contacts the heated member to form a contact area extending along the long side direction of the heating member; and a pressurizing adjusting member that adjusts the pressurized state based on the pressurizing member so that the short side width of the contact area changes, and the heating member has a plurality of heating elements extending along the long side direction. A heating resistor, wherein a high heating portion with a narrow width and a high heating value and a low heating portion with a wide width and a low heating value are connected to the plurality of heating resistors. For at least two of the plurality of heating resistors, the high heating portion is formed in respectively different regions in the long side direction of the contact region. When a minimum contact region with the smallest width in the short side direction of the contact region is formed by the pressure member, for the at least two heating resistors, the high heating portion is included in the range of the minimum contact region, a portion of the low heating portion is included in the range of the minimum contact region, and the remaining portion of the low heating portion exceeds the range of the minimum contact region.

[0007] The second technical feature of the present invention is that in a heating device having the first technical feature, the heating component has a first heating resistor and a second heating resistor extending along the long side direction, a high heating portion with a narrow width and high heat generation and a low heating portion with a wide width and low heat generation are connected to form on the first heating resistor, and the high heating portion and the low heating portion are connected to form in an area different from the first heating resistor on the second heating resistor, and when a minimum contact area with the smallest width in the short side direction of the contact area is formed by the pressure member, the high heating portions of the first heating resistor and the second heating resistor are both included in the range of the minimum contact area, a part of the low heating portion is included in the range of the minimum contact area, and the remaining part of the low heating portion exceeds the range of the minimum contact area.

[0008] The third technical feature of the present invention is that in the heating device having the first or second technical feature, the pressurizing member includes a pressurizing member, and the pressurizing member is rotatably disposed opposite to the heat generating member with the heated member interposed therebetween.

[0009] A fourth technical feature of the present invention is that in the heating device having the first or second technical feature, the pressurizing member includes a pressing member that presses the heat generating member against the heated member.

[0010] The fifth technical feature of the present invention is characterized in that, in a heating device having any one of the first to fourth technical features, the heated component contacts and heats a heating object medium moving in the contact area or on the downstream side of the rotation direction of the contact area, and the heating component has the plurality of heating resistors, and the plurality of heating resistors are arranged in a manner including a maximum width area in a cross direction intersecting the moving direction of the heating object medium.

[0011] The sixth technical feature of the present invention is characterized in that, in a heating device having the fifth technical feature, the heating component has the plurality of heating resistors, and the plurality of heating resistors heat the heating object medium that moves around a center reference line passing through the center of a crossing direction that intersects with the rotation direction of the heated component.

[0012] The seventh technical feature of the present invention is characterized in that, in a heating device having the second technical feature, the heated component heats a heating object medium that moves around a center reference line passing through the center of a cross direction that crosses the rotation direction of the heated component, and the first heating resistor, which is one of the plurality of heating resistors, forms the high heating portion in an area in the center of the long side direction including the contact area, and forms the low heating portion near the end of the long side direction separated by the high heating portion.

[0013] The eighth technical feature of the present invention is characterized in that, in a heating device having the seventh technical feature, the second heating resistor forms the low heating portion in a region corresponding to the high heating portion of the first heating resistor, and forms the high heating portion in a region corresponding to the low heating portion of the first heating resistor.

[0014] The ninth technical feature of the present invention is characterized in that in a heating device having the first technical feature, the heated component heats a heating object medium that moves around a center reference line passing through the center of an intersecting direction intersecting with the rotation direction of the heated component, and the heating component has a first heating resistor to a third heating resistor, the first heating resistor forms the high heating portion in an area in the center of the long side direction including the contact area, and forms the low heating portion near the end in the long side direction separating the high heating portion, the second heating resistor forms the low heating portion in an area corresponding to the high heating portion of the first heating resistor, and forms the high heating portion in an area corresponding to the low heating portion of the first heating resistor, and the third heating resistor forms the high heating portion in an area in the center of the long side direction including the contact area and narrower than the high heating portion of the first heating resistor, and forms the low heating portion near the end in the long side direction separating the high heating portion.

[0015] The tenth technical feature of the present invention is that in the heating device having any one of the first to ninth technical features, the high heat generation portion and the low heat generation portion are connected via a connecting heat generation portion whose width dimension gradually changes.

[0016] The eleventh technical feature of the present invention is that in the heating device having any one of the first to tenth technical features, the connected heat generating portion is formed in a mountain shape in which a width dimension changes linearly.

[0017] The twelfth technical feature of the present invention is that in the heating device having any one of the first to eleventh technical features, the heating component has an elongated substrate and the plurality of heating resistors formed along the long side direction of the substrate.

[0018] The 13th technical feature of the present invention is characterized in that, in a heating device having the 12th technical feature, the heating component forms the plurality of heating resistors along the long side direction on the surface of the heated component side of the substrate, and covers the plurality of heating resistors with a heat-resistant protective layer.

[0019] The 14th technical feature of the present invention is characterized in that, in a heating device having any one of the 1st to 13th technical features, the heated component contacts and heats a heating object medium moving in the contact area or on the downstream side of the rotation direction of the contact area, and when the heated component is heated without allowing the heating object medium to pass through, the pressurizing component forms the minimum contact area, and the heating component causes at least two of the plurality of heating resistors that include the high heating portion within the range of the minimum contact area to heat up.

[0020] The 15th technical feature of the present invention is characterized in that, in a heating device having the 14th technical feature, when the heating object medium passes through and heats the heated component, the pressing component forms a contact area wider than the minimum contact area, and the heating component combines the multiple heating resistors according to the width dimension in the intersecting direction intersecting the moving direction of the heating object medium to generate heat.

[0021] The 16th technical feature of the present invention is a heating treatment system, characterized in that it comprises: a processing component that performs a predetermined treatment on a heating object medium; and a heating device having any one of the 1st to 15th technical features, which heats the heating object medium after being processed by the processing component.

[0022] The 17th technical feature of the present invention is characterized in that, in a heating processing system having the 16th technical feature, the processing component is an image generating component for producing an unfixed image on the heating object medium, and the heating device is a fixing device for fixing the unfixed image produced on the heating object medium.

[0023] Effects of the Invention

[0024] According to the first technical feature of the present invention, when a plurality of heating resistors are used as heating components to form a heating contact area between a strip-shaped heated component and the heating component, an excessive increase in temperature around the contact area can be suppressed without increasing the pressure load on the contact area.

[0025] According to the second technical feature of the present invention, when two heating resistors are used as heating components to form a heating contact area between a strip-shaped heated component and the heating component, an excessive increase in temperature around the contact area can be suppressed without increasing the pressure load on the contact area.

[0026] According to the third feature of the present invention, in a method of heating the heating target medium in the contact region between the heated member and the heat generating member, an excessive increase in the temperature around the contact region can be suppressed without increasing the pressure load on the contact region.

[0027] According to the fourth technical feature of the present invention, with respect to a method of heating the heating object medium at a position closer to the downstream side of the rotation direction of the heated member than the contact area between the heated member and the heat generating member, it is possible to suppress an excessive increase in the temperature around the contact area without increasing the pressure load on the contact area.

[0028] According to the fifth feature of the present invention, a heating target medium of the maximum size that can be used as a heat generating member can be efficiently heated.

[0029] According to the sixth feature of the present invention, the heating member can efficiently heat the heating target medium moving around the central reference line.

[0030] According to the seventh feature of the present invention, even when the heating target medium moves around the central reference line, heating target media of various sizes can be efficiently heated.

[0031] According to the eighth feature of the present invention, even in an embodiment in which the heat generating member has two heat generating resistors, heating target media of various sizes can be efficiently heated.

[0032] According to the ninth feature of the present invention, even in an embodiment in which the heat generating member has three heat generating resistors, heating target media of various sizes can be efficiently heated.

[0033] According to the tenth technical feature of the present invention, compared with a case where there is no connected heat generating portion, the distribution of the heat generated by the high heat generating portion and the low heat generating portion in the long side direction of the contact region can be made more uniform.

[0034] According to the eleventh technical feature of the present invention, the connected heat generating part can be constructed simply compared with a connected heat generating part that changes in a curved manner.

[0035] According to the twelfth technical feature of the present invention, an existing planar heat generating member can be utilized as the heat generating member.

[0036] According to the 13th technical feature of the present invention, compared with the method of forming a plurality of heating resistors on the opposite side of the heated component of the substrate, the plurality of heating resistors can be brought closer to the heated component, thereby obtaining a more appropriate distribution of heat while avoiding friction with the heated component.

[0037] According to the fourteenth technical feature of the present invention, the heating process by the heating device can be appropriately performed without passing the heating target medium.

[0038] According to the fifteenth technical feature of the present invention, the heating target medium can be passed through and appropriately subjected to the heating treatment of the heating device.

[0039] According to the 16th technical feature of the present invention, a heating treatment system including a heating device can be constructed. In the heating device, a plurality of heating resistors are used as heating components. When a heating contact area is formed between a strip-shaped heated component and the heating component, an excessive increase in temperature around the contact area can be suppressed without increasing the pressure load on the contact area.

[0040] According to the seventeenth technical feature of the present invention, it is possible to provide a heating processing system capable of appropriately heating a heating target medium on which an unfixed image is formed. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Embodiments of the present invention will be described in detail with reference to the following drawings.

[0042] exist Figure 1 middle, Figure 1 (a) is an explanatory diagram showing an overview of an embodiment of a heating treatment system including a heating device to which the present invention is applied, Figure 1 (b) means Figure 1 (a) is an explanatory diagram of the details of the heat generating component shown;

[0043] Figure 2 is an explanatory diagram showing the overall configuration of an image forming system according to Embodiment 1;

[0044] Figure 3 is an explanatory diagram showing a structural example of a fixing device and its surroundings according to Embodiment 1;

[0045] exist Figure 4 middle, Figure 4 (a) is an explanatory diagram showing a structural example of a heat generating component of the fixing device according to the first embodiment, Figure 4 (b) is an explanatory diagram showing the layout of the heating resistor of the heating component in the width direction of the contact area when a narrow contact area is used;

[0046] Figure 5 It is an explanatory diagram showing the pattern of a plurality of heating resistors of the heating component and the amount of heat generated in the first embodiment;

[0047] Figure 6 is an explanatory diagram showing an example of a contact area variable mechanism used in Embodiment 1;

[0048] exist Figure 7 middle, Figure 7 (a) is an explanatory diagram showing the operation state when a wide normal contact area is set by the contact area variable mechanism, Figure 7 (b) is an explanatory diagram showing the operation state when the minimum contact area with a narrow width is set by the contact area variable mechanism;

[0049] Figure 8 is a flowchart showing a heating and pressurizing process of the fixing device according to the first embodiment;

[0050] exist Fig. 9 middle, Fig. 9(a) is an explanatory diagram showing the layout of the heat generating parts of the fixing device according to Comparative Example 1 in a narrow contact region. Fig. 9 (b) means for Fig. 9 An explanatory diagram of a solution to the technical problem shown in (a);

[0051] Fig.10 is an explanatory diagram showing the main parts of the contact area variable mechanism involved in deformation mode 1-1;

[0052] Fig.11 This is an explanatory diagram showing an example of a heating resistor of a heating component when the medium conveying method adopts a side reference method using one side in the width direction intersecting with the moving direction of the medium as a reference;

[0053] Fig.12 is an explanatory diagram showing a pattern of a plurality of heating resistors of a heat generating component of a fixing device according to a second embodiment and the amount of heat generated;

[0054] exist Fig.13 middle, Fig.13 (a) is an explanatory diagram showing the layout of the heating resistor of the heating component in the width direction of the contact area when a normal contact area with a wide width is used, Fig.13 (b) is an explanatory diagram showing the layout of the heating resistor of the heating component in the width direction of the contact area when a minimum contact area with a narrow width is used;

[0055] Fig.14 is an explanatory diagram showing a main part of a fixing device according to Embodiment 3;

[0056] Fig.15 is an explanatory diagram showing the details of the structure of the heat generating parts and the surrounding areas of the fixing device according to the third embodiment;

[0057] exist Fig.16 middle, Fig.16 (a) is an explanatory diagram showing the layout of heat generating parts when using a narrow minimum contact area. Fig.16 (b) is an explanatory diagram showing the layout of heat generating components when a normal contact area with a wide width is used. DETAILED DESCRIPTION

[0058] ◎Overview of implementation method

[0059] exist Figure 1 (a) shows an overview of the first embodiment of the heating processing system including the fixing device to which the present invention is applied.

[0060] exist Figure 1In (a), the heat treatment system includes: a treatment unit 10 for performing a predetermined treatment on a heating target medium S; and a heating device 11 for heating the heating target medium S after being treated by the treatment unit 10 .

[0061] As such a heat treatment system, for example, a system can be exemplified in which the treatment unit 10 is an image generating unit for generating an unfixed image on the medium S to be heated, and the heating device 11 is a fixing device for fixing the unfixed image generated on the medium S to be heated.

[0062] In this example, the heating device 11 comprises: a belt-shaped heated member 1 that circulates and rotates; a heating member 2 that is arranged in contact with the back side of the heated member 1 and extends in a direction that intersects with the rotation direction of the heated member 1 and heats the heated member 1; a pressurizing member 4 that brings the heated member 1 and the heating member 2 into contact under a pressurized state, and contacts the heated member 1 to form a contact area CN that extends in the long side direction of the heating member 2; and a pressurizing adjusting member 5 that adjusts the pressurized state based on the pressurizing member 4 so that the width of the contact area CN in the short side direction changes, and the heating member 2 is as shown in FIG. Figure 1 As shown in (b) of FIG. 1 , a plurality of heating resistors 3 (3a, 3b) extending in the long side direction are provided, and a high heating portion 6 having a narrow width and a high heat generation and a low heating portion 7 having a wide width and a low heat generation are connected to the plurality of heating resistors 3. For at least two of the plurality of heating resistors (3a, 3b) 3, the high heating portion 6 is formed in different regions in the long side direction of the contact area CN, and the minimum contact area CN having the smallest width in the short side direction of the contact area CN formed by the pressure member 4 is formed. S When at least two of the plurality of heating resistors 3 (3a, 3b) have high heat generation portions 6 included in the minimum contact area CN S A part of the low heat generation portion 7 is included in the minimum contact area CN S The remaining portion of the low heat generating portion 7 exceeds the minimum contact area CN S range.

[0063] In this example, when the heat generating component 2 has three or more heat generating resistors 3, two of the heat generating resistors (3a, 3b) need to be arranged in the minimum contact area CN as described above. S At this time, when using the minimum contact area CN S Therefore, for heating resistors other than the two heating resistors (3a, 3b), it is sufficient to appropriately select their patterns (patterns of the high heating portion 6 and the low heating portion 7) by taking into account the size of the medium S to be heated.

[0064] In contrast, in a mode in which the heat generating component 2 has two heat generating resistors 3, specifically, a first heat generating resistor 3a and a second heat generating resistor 3b extending in the long side direction, it is sufficient to form the following configuration: a high heat generating portion 6 having a narrow width and a high heat generating amount and a low heat generating portion 7 having a wide width and a low heat generating amount are connected to the first heat generating resistor 3a, and the high heat generating portion 6 and the low heat generating portion 7 are connected to the second heat generating resistor 3b in a region different from the first heat generating resistor 3a, and a minimum contact region CN having the smallest width in the short side direction of the contact region CN formed by the pressurizing member 4 is formed. S When the high heat generating portions 6 of the first heating resistor 3a and the second heating resistor 3b are both included in the minimum contact area CN S A part of the low heat generation portion 7 is included in the minimum contact area CN S The remaining portion of the low heat generating portion 7 exceeds the minimum contact area CN S range.

[0065] In this technical means, the heated member 1 only needs to be a belt-shaped heated member that circulates and rotates. As a circulating rotation method of the heated member 1, for example, one of the tensioning members that tension the heated member 1 can be used as a driving source to drive the heated member 1 to rotate, or the pressure member 4 can be used as a driving source to drive the heated member 1 to rotate.

[0066] Furthermore, the heat generating member 2 may be a heat generating member arranged in contact with the back surface of the heated member 1, and is not limited to being arranged opposite to the pressurizing member 4. Furthermore, the heat generating member 2 is typically a heat generating member using a planar heat generating body, but heat generating members other than a planar heat generating body may also be applied.

[0067] Furthermore, the pressurizing member 4 may be appropriately selected as long as it brings the heated member 1 and the heat generating member 2 into contact with each other under pressure.

[0068] Furthermore, the pressure adjustment member 5 may be any member that adjusts the pressure state of the pressure adjustment member 4. In this example, the pressure adjustment member may be any member that changes the pressure load to make the width of the contact area CN variable and to form a contact area including the minimum contact area CN. S And there are at least a plurality of contact regions CN with different widths.

[0069] Next, representative aspects or preferred aspects of the heating device 11 according to the present embodiment will be described.

[0070] In this example, as a representative form of the pressurizing member 4, there is a form in which a pressurizing member is rotatably arranged opposite to the heat generating member 2 across the heated member 1. In addition, as another form, there is a form in which a pressing member presses the heat generating member 2 against the heated member 1.

[0071] Furthermore, in a method in which the heated component 1 contacts the heating object medium S moving in the contact area CN or on the downstream side of the rotation direction of the contact area CN and heats the heating object medium S, it is necessary to have a plurality of heating resistors 3 as the heating component 2 so as to include a maximum width area in a cross direction intersecting the moving direction of the heating object medium S.

[0072] At this time, if Figure 1 As shown in (b), the heating component 2 only needs to be a heating component having a plurality of heating resistors 3, and the plurality of heating resistors 3 heat the heating target medium S moving around a center reference line Lc passing through the center of a crossing direction intersecting with the rotation direction of the heated component 1.

[0073] In the case where the heating member 2 includes two heating resistors 3 (3a, 3b), when the heated member 1 heats the heating target medium S moving around the center reference line Lc passing through the center of the intersecting direction intersecting the rotation direction of the heated member 1, Figure 1 As shown in (b), the first heating resistor 3a, which is one of the multiple heating resistors 3, can be a heating resistor that forms a high heating portion 6 in an area in the center of the long side direction including the contact area CN and a low heating portion 7 near the end of the long side direction separated by the high heating portion 6.

[0074] The second heating resistor 3b only needs to form the low heating portion 7 in a region corresponding to the high heating portion 6 of the first heating resistor 3a and the high heating portion 6 in a region corresponding to the low heating portion 7 of the first heating resistor 3a.

[0075] Furthermore, in the case where the heated component 1 heats the heating target medium S moving about the center reference line Lc, in the case where the heating component 2 has three heating resistors 3 (specifically, the first heating resistor 3a, the second heating resistor 3b, and the third heating resistor not shown), from the viewpoint of effectively heating the heating target medium S of various sizes, Figure 1As shown in (b), the first heating resistor 3a may be configured as follows: the first heating resistor 3a may be configured to form a high heating portion 6 in a region including the center of the contact region CN in the longitudinal direction, and a low heating portion 7 may be formed near the end of the long side across the high heating portion 6; the second heating resistor 3b may be configured to form a low heating portion 7 in a region corresponding to the high heating portion 6 of the first heating resistor 3a, and a high heating portion 6 may be formed in a region corresponding to the low heating portion 7 of the first heating resistor 3a; the third heating resistor (not shown) may be configured to form a high heating portion 6 in a region including the center of the contact region CN in the longitudinal direction and narrower than the high heating portion 6 of the first heating resistor 3a, and a low heating portion 7 may be formed near the end of the long side across the high heating portion 6. In this embodiment, the third heating resistor (not shown) may be used mainly when a small-sized medium S is used as a heating object, and the first heating resistor 3a and the second heating resistor 3b may be used only at the start-up operation and when a medium S of a size other than a small size is used as a heating object. In addition, the combination of patterns of the first heating resistor 3 a to the third heating resistor may be appropriately selected.

[0076] Furthermore, as the pattern of the heating resistor 3, Figure 1 As shown in (b), from the perspective of preventing the heat generation pattern from changing sharply between the high heat generation portion 6 and the low heat generation portion 7, it is preferred that the high heat generation portion 6 and the low heat generation portion 7 are connected via a connecting heat generation portion 8 whose width dimension gradually changes.

[0077] In this example, as a method of connecting the heat generating portion 8, there can be mentioned a method of forming it into a mountain shape in which the width dimension changes linearly.

[0078] Furthermore, as a representative embodiment of the heat generating member 2, there is mentioned an embodiment including an elongated substrate (not shown) and a plurality of heat generating resistors 3 formed along the longitudinal direction of the substrate.

[0079] In this example, as a form of the heat generating component 2, a plurality of heat generating resistors 3 are formed along the longitudinal direction on the surface of the substrate on the heated component 1 side and the plurality of heat generating resistors 3 are covered with a heat-resistant protective layer (not shown).

[0080] Furthermore, in a mode in which the heated member 1 contacts the heating target medium S moving in the contact area CN or on the downstream side of the rotation direction of the contact area CN and heats the heating target medium S, when the heated member 1 is heated without passing the heating target medium S, for example, the pressurizing member 4 preferably forms the minimum contact area CN. S The heating component 2 makes the heating resistors 3 have the smallest contact area CN S At least two heating resistors 3 (3a, 3b) including the high heating portion 6 generate heat within the range.

[0081] In this example, it is sufficient that when the heating target medium S passes through and heats the heated member 1, the pressing member 4 forms a minimum contact area CN with a width greater than 1. S In the wider contact region CN, the heat generating member 2 combines a plurality of heat generating resistors 3 according to the width dimension in the direction intersecting the moving direction of the heating target medium S to generate heat.

[0082] Hereinafter, the present invention will be described in more detail based on the embodiments shown in the drawings.

[0083] ◎Implementation method 1

[0084] -Overall structure of image forming system-

[0085] Figure 2 This is an explanatory diagram showing the overall configuration of the heat treatment system according to the first embodiment.

[0086] exist Figure 2 In the embodiment, the heating processing system is constituted as an image forming system 20, which comprises: an image generating component as a processing component, which produces an unfixed image on a heating object medium S (hereinafter referred to as medium S in the embodiment); and a fixing device as a heating device, which fixes the unfixed image produced on the medium S.

[0087] In this example, the image forming system 20 is a so-called tandem type intermediate transfer system, and each component as an image generating member and a fixing device are mounted in a common unit (not shown). In addition, of course, the image generating member and the fixing device may be configured as separate units or a plurality of units may be combined.

[0088] In this example, the image forming system 20 has a plurality of image forming units 22 (22a to 22d) that form toner images of various color components (in this example, four colors, namely yellow (Y), magenta (M), cyan (C), and black (K)) by means of an electrophotographic method. Furthermore, a belt-shaped intermediate transfer body 23 is provided at a position corresponding to each image forming unit 22. Furthermore, a primary transfer device 24 (in this example, a primary transfer roller) is provided on the back side of the intermediate transfer body 23 corresponding to each image forming unit 22. Furthermore, a secondary transfer device 25 (in this example, a secondary transfer roller) is provided on a portion of the intermediate transfer body 23 for secondary transferring the toner images of various color components that are primarily transferred from each image forming unit 22 to the intermediate transfer body 23 by the primary transfer device 24 to a medium S such as paper. Furthermore, a fixing device 60 is disposed downstream in the conveying direction of the medium S to which the toner image of the color component is transferred, and fixes the unfixed toner image (corresponding to the unfixed image) on the medium S.

[0089] In addition, in this example, the plurality of image forming sections 22 , the intermediate transfer body 23 , the primary transfer device 24 , and the secondary transfer device 25 correspond to image generating means for forming an unfixed image on the medium S.

[0090] <Image forming unit>

[0091] Here, each image forming unit 22 has a drum-shaped photosensitive body 30 rotating in a predetermined direction, and is equipped around the photosensitive body 30 with a charging device 31 for charging the photosensitive body 30, an exposure device 32 such as a laser scanning device for writing an electrostatic latent image on the photosensitive body 30 charged by the charging device 31, a developing device 33 for developing the electrostatic latent image written on the photosensitive body 30 by the exposure device 32 with a corresponding colorant, and a cleaning device 34 for cleaning residues on the photosensitive body 30 after the colorant image developed by the developing device 33 is transferred to the intermediate transfer body 23 by the primary transfer device 24.

[0092] <Around the intermediate transfer body>

[0093] The intermediate transfer body 23 is mounted on a plurality of tension rollers 41 to 45, and the tension roller 41 is used as a driving roller to circulate in a predetermined direction. The tension roller 44 also serves as an opposing roller of the secondary transfer roller of the secondary transfer device 25, and a secondary transfer electric field required for the secondary transfer is generated between the secondary transfer roller and the opposing roller. An intermediate transfer cleaning device 46 is provided on the surface of the intermediate transfer body 23 corresponding to the tension roller 45.

[0094] <Media transmission system>

[0095] Furthermore, a medium supply device 50 is provided below the intermediate transfer body 23, and the medium S supplied from the medium supply device 50 is conveyed along a conveying path 51 that passes through the secondary transfer device 25 and reaches the fixing device 60. In addition, the conveying path 51 is provided with an appropriate number of conveying rollers 52, a conveying belt 53 that conveys from the secondary transfer device 25 to the fixing device 60, guide plates 54 and 55 that guide the medium S to the secondary transfer portion based on the secondary transfer device 25 and the fixing portion of the fixing device 60, and a discharge roller 56 for discharging the medium S to a medium discharge portion (not shown).

[0096] In this example, the medium S is formed by a center reference line Lc (reference Figure 5 ) as the center of movement.

[0097] -Overall structure of the fixing device-

[0098] Next, use Figure 3 The fixing device 60 used in this embodiment will be described.

[0099] exist Figure 3 In the embodiment, the fixing device 60 has a width dimension required for fixing the medium S moving in the conveying direction. The fixing device 60 includes: a fixing belt 61 as a heated member that circulates and rotates; a heating component 62 as a heating component that is disposed in contact with the back side of the fixing belt 61 and heats the fixing belt 61; a pressure roller 63 that is disposed in contact with a portion that is opposed to the heating component 62 across the fixing belt 61 and applies pressure in a manner that forms a contact area CN between the fixing belt 61 and the fixing belt 61; an upstream tension roller 64 that circulates and rotatably tensions the fixing belt 61 on the upstream side of the fixing belt 61 in the moving direction relative to the contact area CN; and a downstream tension roller 65 that circulates and rotatably tensions the fixing belt 61 on the downstream side of the fixing belt 61 in the moving direction relative to the contact area CN.

[0100] - Example of the structure of the fixing belt -

[0101] In this example, the fixing belt 61 is an endless heat-conducting belt having flexibility and heat resistance. As the fixing belt 61, for example, a belt formed into a cylindrical shape using a synthetic resin such as polyimide or polyamide is suitable.

[0102] In this example, either the upstream tension roller 64 or the downstream tension roller 65 (in this example, the downstream tension roller 65) functions as a driving roller driven to rotate by a driving motor (not shown). In addition, the other one (in this example, the upstream tension roller 64) functions as a tension applying roller that applies tension to the fixing belt 61. In addition, from the viewpoint of preventing the fixing belt 61 from deflecting, the upstream tension roller 64 is supported so as to be tiltable, and it can also be set to function as a steering roller.

[0103] -Heating parts-

[0104] In this example, the heat generating component 62 directly heats the back surface of the fixing belt 61 and heats the medium S conveyed under pressure in the contact region CN sandwiched between the fixing belt 61 and the pressure roller 63 via the fixing belt 61 .

[0105] In this example, the heating component 62 is arranged on the back side of the fixing belt 61 corresponding to the contact area CN, and has a long plate-shaped surface heater 70 extending in the width direction intersecting the conveying direction of the medium S and a heater holder 75 for holding the surface heater 70, and the heater holder 75 is fixed to a predetermined position via a support bracket 78.

[0106] <Example of the structure of a planar heater>

[0107] In this example, if Figure 4 As shown in (a), the planar heater 70 is positioned and accommodated in a recess 76 formed in a heater holder 75, and is fixed by a fixing device. The planar heater 70 includes: a long substrate 71; a plurality of heating resistors 72, which are arranged on the surface of the substrate 71 on the side in contact with the inner peripheral surface of the fixing belt 61 and extend along the long side direction of the substrate 71; wiring electrodes (not shown) are arranged near the two ends of the heating resistor 72 in the long side direction of the substrate 71 and are used to supply power to the heating resistor 72; and an insulating layer 73, which is stacked on the surface of the substrate 71 on the fixing belt 61 side in a manner covering the heating resistor 72 and the wiring electrodes.

[0108] Here, the substrate 71 is a rectangular plate-shaped member whose length in the width direction intersecting the conveying direction of the medium S is longer than its maximum dimension. The substrate 71 is made of an electrically insulating material, such as a ceramic substrate.

[0109] The insulating layer 73 may be appropriately selected, and for example, glass may be used.

[0110] <Example of the structure of the heating resistor>

[0111] In this example, the heating resistor 72 is a belt-shaped heating resistor having a predetermined resistance value formed by printing and firing a metal paste mainly composed of a silver (Ag) / palladium (Pd) alloy, for example.

[0112] Furthermore, in this example, the heating resistor 72 has a plurality of (two in this example) heating wire portions 72a, 72b extending linearly along its long side direction on a single surface of the substrate 71, and these heating wire portions 72a, 72b are arranged at intervals in the short side direction of the substrate 71.

[0113] Here, if the heating wire portion 72a of the heating resistor 72 is set as the first heating resistor R1 and the heating wire portion 72b is set as the second heating resistor R2, Figure 5 As shown in FIG. 1 , the first heating resistor R1 and the second heating resistor R2 are configured in the following pattern.

[0114] The length d0 of the first heating resistor R1 and the second heating resistor R2 in the longitudinal direction is selected to include the width dimension of the medium size used and intersecting the conveying direction (for example, the short-side dimension of JIS standard A4 size paper).

[0115] The line widths of the first heating resistor R1 and the second heating resistor R2 are set as follows according to the regions in the longitudinal direction.

[0116] The first heating resistor R1 is set as a high heating portion 721 with a thin line width of the heating material and a large resistance in an area of ​​length d1 (for example, the short side dimension of JIS standard A5 size paper), so that the area generates heat with a high heat generation to the left and right based on the center (center reference line Lc) of the heating area along the long side direction. In addition, the low heating portion 722 is set as a heating material with a thick line width and a small resistance, so that the areas at the two ends of the heating area of ​​the high heating portion 721 do not generate heat.

[0117] The second heating resistor R2 is set as a low heating portion 722 with a thick heating material and a small resistance in the region of length d1, so that the region does not generate heat to the left and right based on the center (center reference line Lc) of the heating region along the long side direction. In addition, the high heating portion 721 is set as a heating material with a thin heating material and a large resistance, so that the regions at both ends of the heating region of the low heating portion 722 generate heat with a high calorific value.

[0118] Furthermore, in this example, as the first heating resistor R1 and the second heating resistor R2, a method is adopted in which the high heating portion 721 and the low heating portion 722 are connected via a connecting heating portion 723 whose width dimension changes gradually, so as to prevent the heat generation pattern from changing sharply between the high heating portion 721 and the low heating portion 722. Here, as the connecting heating portion 723, for example, a method in which a mountain shape whose width dimension changes linearly can be used.

[0119] Thus, in this example, the first heating resistor R1 and the second heating resistor R2 are both formed by connecting the high heating portion 721 and the low heating portion 722, but the positional relationship between the high heating portion 721 and the low heating portion 722 in the long side direction is opposite to each other. Therefore, the heat generation of the first heating resistor R1 and the second heating resistor R2 in the long side direction is as follows: Figure 5 As shown, if the two are added together, a roughly uniform heating value can be obtained.

[0120] -Pressure roller-

[0121] And, if Figure 3 As shown in FIG. 1 , the pressure roller 63 is formed by laminating an elastic material 63 b such as urethane rubber around a metal roller 63 a , and a protective layer 63 c is laminated on the surface of the elastic material.

[0122] In this example, the pressure roller 63 rotatably supports the shaft portions of the metal roller 63 a at both ends via bearings 67 .

[0123] Moreover, in this example, the pressure roller 63 contacts and separates between a fixed (set) position in contact with the fixing belt 61 via the retracting mechanism 80 and a retracted position in contact with the fixing belt 61. In this example, the retracting mechanism 80 has a swing holding arm 81 that swings around a swing support shaft 82, and a U-shaped groove 83 is formed on the swing holding arm 81 to receive the bearings 67 located at both ends of the pressure roller 63, so that the pressure roller 63 contacts and separates.

[0124] -Contact area variable mechanism-

[0125] In this example, if Figure 3 As shown, a contact region variable mechanism 90 for making the width dimension of the contact region CN along the conveying direction of the medium S variable is provided.

[0126] exist Figure 6 An example of the contact area variable mechanism 90 used in the first embodiment is shown in FIG.

[0127] exist Figure 6 In the embodiment, the contact area variable mechanism 90 is constructed by utilizing the retracting mechanism 80 of the pressure roller 63 .

[0128] In this example, the retracting mechanism 80 has a contact / separation mechanism 85 for making the pressure roller 63 contact and separate with respect to the fixing belt 61. In the contact / separation mechanism 85, a protruding piece 851 is protruded on the free end side of the swing holding arm 81, and an eccentric cam 852 is contacted on the lower side of the protruding piece 851, and a biasing spring 853 for biasing the protruding piece 851 toward the eccentric cam 852 side is provided on the opposite side of the eccentric cam 852 of the protruding piece 851, and the eccentric cam 852 is switched and rotated to the long-diameter position RL and the short-diameter position RS by the driving motor 854.

[0129] In this example, in the retraction mechanism 80, when the short-diameter position RS of the eccentric cam 852 abuts against the protrusion piece 851, the pressure roller 63 retreats to the retracted position, and when the long-diameter position RL of the eccentric cam 852 abuts against the protrusion piece 851, the pressure roller 63 is configured at a fixed position.

[0130] In this example, the contact area variable mechanism 90 utilizes the middle diameter position other than the long diameter position RL and the short diameter position RS of the eccentric cam 852 in the contact / separation mechanism 85 of the retraction mechanism 80 to rotate the pressure roller 63 around the swing support shaft 82 of the swing retaining arm 81 so that the width dimension of the contact area CN can be changed.

[0131] In this example, when the long diameter position RL of the eccentric cam 852 abuts against the protruding piece 851, the pressure roller 63 is arranged at a fixed position. Figure 7 As shown, it is assumed that the pressure roller 63 is used to ensure a wide contact area CN used in normal printing. L Configuration (refer to Figure 4 (a)). In addition, the posture position of the swing holding arm 81 is represented by Q1 in the figure.

[0132] On the other hand, Figure 7 As shown, configure as follows ( Figure 4 (b)): If the driving motor 854 is stopped at the position where the middle diameter position RM (RS<RM<RL) of the eccentric cam 852 abuts against the protruding piece 851, the posture position of the swing holding arm 81 is tilted from Q1 to Q2 by only ΔQ, and as a result, the pressure roller 63 ensures a minimum contact area CN with a narrow width and a minimum width dimension. S .

[0133] In this example, the contact area CN is changed to a normal contact area CN having a wide width. L Minimum contact area CN with narrow width S These two, however, are not limited thereto, and of course, the contact region CN located between them may be more appropriately selected according to the physical properties and size of the medium.

[0134] - Relationship between the change of contact area and the pattern of heating resistor -

[0135] As described above, the contact area CN between the fixing belt 61 and the pressure roller 63 is changed by the contact area variable mechanism 90 to a normal contact area CN having a wide width. L Minimum contact area CN with narrow width S .

[0136] In this state, the high heat generating portions 721 of the first heat generating resistor R1 and the second heat generating resistor R2 are positioned so as to be located in the wide contact area CN. L or the minimum contact area CN with narrow width S In either case, it is included in the contact area CN.

[0137] -Peripheral structure of the fixing device-

[0138] In this example, if Figure 3 and Figure 5 As shown, a surface temperature sensor SN is provided to detect the surface temperature of the fixing belt 61 upstream of the contact region CN in the rotation direction. As the surface temperature sensor SN, a known sensor using a thermistor, a temperature measuring resistor, or the like may be appropriately selected.

[0139] In this example, two surface temperature sensors can be used as the surface temperature sensor SN.

[0140] One of the surface temperature sensors SN1 detects the surface temperature of the fixing belt 61 corresponding to the medium passing area. In this example, one of the surface temperature sensors SN1 detects the surface temperature near the center reference line Lc in the fixing belt 61.

[0141] The other surface temperature sensor SN2 detects the surface temperature of the fixing belt 61 corresponding to the medium non-passing region.

[0142] In addition, a position sensor 110 for detecting the position of the medium S is provided on the conveying path 51 on the upstream side of the entrance of the fixing device 60 in the conveying direction of the medium S. The position sensor 110 is used to start counting of the timing counter and find the position of the medium S by detecting the front end or the rear end of the conveyed medium S.

[0143] Furthermore, the media type indicating unit 120 indicates physical property information such as the size or thickness of the medium S being transmitted. However, the size or physical property information of the medium S may be detected during the transmission of the medium S and the detected information may be used as the indication information.

[0144] -Control system of fixing device-

[0145] exist Figure 3 In the figure, symbol 100 is a control device composed of a microcomputer including various processors. The "processor" mentioned here refers to a processor in a broad sense, including a general-purpose processor (such as CPU: Central Processing Unit, etc.) or a dedicated processor (such as GPU: Graphics Processing Unit, ASIC: Application Specific Integrated Circuit, FPGA: Field Programmable Gate Array, programmable logic device, etc.).

[0146] In this example, the control device 100 pre-installs a heating and pressurizing processing program of the fixing device in a memory (not shown) (see Figure 8 ), the operation signal from the operation panel not shown, the information from the position sensor 110, the surface temperature sensor SN, and the media type indication unit 120 are read into the processor, and the processor executes various programs to control the predetermined control signals of the surface heater 70, the retraction mechanism 80, the contact area variable mechanism 90, etc.

[0147] -Heating and pressurizing treatment of the fixing device-

[0148] Now, assuming that a printing instruction is issued from an operation panel (not shown), the control device 100 executes a series of image forming processes.

[0149] When the fixing device 60 receives a print instruction but the heating conditions of the fixing device and the pressing conditions of the pressing roller 63 are not yet prepared, the fixing device 60 is started up.

[0150] Here, when it is determined that the control device 100 is activated, the contact area variable mechanism 90 is used to narrow the contact area CN. That is, the contact area CN is set to the minimum contact area CN. S (refer to Figure 4 (b) and Figure 5 ).

[0151] In this state, the control device 100 monitors the temperature information from the surface temperature sensor SN1 and energizes the first heating resistor R1 and the second heating resistor R2 simultaneously to heat the fixing belt 61 until the fixing belt 61 reaches a predetermined value Tm (equivalent to the temperature required for the fixing action).

[0152] In this startup operation, the high heat generating portions 721 of the first heating resistor R1 and the second heating resistor R2 are in the minimum contact area CN. S Since the fixing belt 61 is heated with a high heat, the heating process of the fixing belt 61 is efficiently performed in a short time.

[0153] At this time, the high heat generating portion 721 of the first heating resistor R1 and the second heating resistor R2 does not exceed the minimum contact area CN. S range, so the minimum contact area CN S The surrounding area will not be overheated.

[0154] Next, when the start-up operation of the fixing device 60 is completed, the control device 100 sets the contact area CN to a wide state. That is, the contact area CN is set to a normal contact area CN during printing. L .

[0155] In this state, the control device 100 performs a fixing process suitable for printing. That is, the control is performed such that the temperature acquired by the surface temperature sensor SN1 is set to a certain value so that the medium passing area in the long side direction is in a good fixing state, and the temperature acquired by the surface temperature sensor SN2 does not exceed the threshold value Tth so that the medium non-passing area in the long side direction does not exceed the heat resistance temperature of various components.

[0156] ■ When printing on a medium of a small size (for example, JIS standard A5 size) or smaller, the first heating resistor R1 is controlled to be turned on and off, and the second heating resistor R2 is turned off.

[0157] ■When printing on a medium larger than the small size,

[0158] (i) When the temperature acquired by the surface temperature sensor SN2 is equal to or lower than the threshold value Tth, the first heating resistor R1 and the second heating resistor R2 are controlled to be turned on and off.

[0159] (ii) In cases other than (i), the first heating resistor R1 is controlled to be turned on and off, and the second heating resistor R2 is turned off.

[0160] ◎Comparison method 1-1

[0161] When evaluating the performance of the fixing device according to the present embodiment, the fixing device according to Comparative Example 1-1 will be described.

[0162] Now, if Fig. 9As shown in (a), it is assumed that the pressure roller 63 is pressed with a pressure load P1 so that the contact area CN becomes a minimum contact area CN with a narrow width. S The first heating resistor R1 and the second heating resistor R2 are arranged so that the first heating resistor R1 exceeds the minimum contact area CN. S The state configuration of the scope.

[0163] At this time, beyond the minimum contact area CN S When the first heating resistor R1 is heated, except for the minimum contact area CN S The fixing belt 61 other than the fixing belt 61 is arranged in a state of not contacting the pressure roller 63. Therefore, since the heat of the fixing belt 61 heated by the first heating resistor R1 does not transfer to the pressure roller 63, the minimum contact area CN of the fixing belt 61 is S The surrounding temperature rises abnormally.

[0164] In order to eliminate this undesirable situation, Fig. 9 As shown in (b), the pressure load P1 applied to the pressure roller 63 needs to be increased to P2 (> P1) so that the first heating resistor R1 and the second heating resistor R2 are included in the wide contact area CN. L Therefore, it is difficult to reduce the pressurizing load.

[0165] ◎Deformation method 1-1

[0166] In the present embodiment, the contact area variable mechanism 90 adopts a method of moving the pressure roller 63 relative to the fixing belt 61, but is not limited to this. Fig.10 As shown, a contact area variable mechanism 90 can be constructed.

[0167] In this example, in the contact area variable mechanism 90, guide protrusions 91 cut into a D shape are protruded at both ends in the long side direction of the support bracket 78 of the heat generating component 62, and brackets (not shown) are arranged on both sides of the guide protrusions 91. In addition, in the contact area variable mechanism 90, a long hole (not shown) extending in the width direction of the contact area CN along the conveying direction of the medium S is formed on the bracket, and the guide protrusion 91 is slidably (slidingly) inserted into the long hole, so that the heat generating component 62 is arranged to be linearly movable along the width direction of the contact area CN (x direction in the figure).

[0168] Furthermore, in the contact area variable mechanism 90, a protrusion piece 92 extending in a direction orthogonal to the width direction of the contact area CN is provided on a part of the support bracket 78, and an eccentric cam 93 is arranged in contact with the protrusion piece 92. Furthermore, in the contact area variable mechanism 90, a biasing spring 94 is arranged on the opposite side of the protrusion piece 92 from the eccentric cam 93 to bias the protrusion piece 92 toward the eccentric cam 93 side, and the eccentric cam 93 is switched and rotated to the long diameter position RL and the short diameter position RS by the drive motor 95.

[0169] In this example, if Fig.10 As shown, when the short diameter position RS of the eccentric cam 93 abuts against the protruding piece 92, the heat generating part 62 ensures a wide contact area CN used in normal printing. L Configured in this way.

[0170] On the other hand, Fig.10 As shown in the figure, when the long diameter position RL of the eccentric cam 93 abuts against the protruding piece 92, the heat generating component 62 moves toward the entrance side of the medium S along the width direction of the contact area CN (the x direction in the figure) to ensure the minimum contact area CN with a narrow width. S Configured in this way.

[0171] ◎Deformation method 1-2

[0172] In this embodiment, the planar heater 70 of the heating component 62 sets the patterns of the first heating resistor R1 and the second heating resistor R2 (high heating portion 721 and low heating portion 722) based on a method (center reference method) of transmitting the medium S with the center of the width direction of the medium S (center reference line Lc) as a reference.

[0173] However, if Fig.11 As shown, in the case of a method (side reference method) in which the medium S is conveyed based on one side (side reference line Ls) in the width direction of the medium S, the passing area of ​​the medium S of different sizes with respect to the fixing belt 61 is different from the center reference method.

[0174] Therefore, in Fig.11 In the side reference method shown, the small-sized medium S passes near the side reference line Ls of the fixing belt 61, so the patterns of the first heating resistor R1 and the second heating resistor R2 are configured as follows.

[0175] like Fig.11As shown, the first heating resistor R1 is set as a high heating portion 721 with a thin line width of the heating material and a large resistance in an area of ​​length d1 (for example, the short side dimension of JIS standard A5 size paper), so that the area generates heat with a high heat value based on one side (side reference line Ls) of the heating area along the long side direction. And, the low heating portion 722 is set as a heating material with a thick line width and a small resistance, so that the area on the opposite side of the heating area of ​​the high heating portion 721 does not generate heat.

[0176] The second heating resistor R2 is set as a low heating portion 722 with a thick line width of the heating material and a small resistance in the region of length d1, so that the region does not generate heat based on one side (side reference line Ls) of the heating region along the long side direction. In addition, the high heating portion 721 is set as a thin line width of the heating material and a large resistance, so that the region located on the opposite side of the heating region of the low heating portion 722 generates heat with a high calorific value.

[0177] In this example, both the first heating resistor R1 and the second heating resistor R2 are configured such that the high heating portion 721 is connected to the low heating portion 722 via the connecting heating portion 723 .

[0178] Thus, in this example, the first heating resistor R1 and the second heating resistor R2 are also formed by connecting the high heating portion 721 and the low heating portion 722, but the positional relationship of the high heating portion 721 and the low heating portion 722 is opposite to each other in the long side direction. Therefore, if the heating values ​​of the first heating resistor R1 and the second heating resistor R2 at the long side direction are added together, a substantially uniform heating value can be obtained.

[0179] ◎Implementation method 2

[0180] Fig.12 This is an explanatory diagram showing the pattern of a plurality of heating resistors of a heat generating component of a fixing device according to a second embodiment and the amount of heat generated.

[0181] exist Fig.12 In the embodiment, the heating component 62 holds the planar heater 70 on the heater holder 75 in substantially the same manner as in the first embodiment, but the number and pattern of the heating resistors 72 of the planar heater 70 are different from those in the first embodiment. In addition, the same reference numerals as in the first embodiment are given to the same components as those in the first embodiment, and detailed descriptions thereof are omitted here.

[0182] In this example, the heating resistor 72 has a plurality of (three in this example) heating wire portions 72a, 72b, 72c extending linearly along its long side direction on a single surface of the substrate 71, and these heating wire portions 72a, 72b, 72c are arranged at intervals in the short side direction of the substrate 71.

[0183] Here, if the heating wire portion 72a of the heating resistor 72 is set as the first heating resistor R1, the heating wire portion 72b is set as the second heating resistor R2, and the heating wire portion 72c is set as the third heating resistor R3, then Fig.12 As shown in FIG. 1 , the first heating resistor R1 , the second heating resistor R2 , and the third heating resistor R3 are configured in the following pattern.

[0184] The lengths of the first heating resistor R1, the second heating resistor R2 and the third heating resistor R3 in the longitudinal direction are set to a length d0 corresponding to the predetermined maximum size of the medium S (for example, the short-side dimension of JIS standard A3 Nobi). The line widths are set as follows according to the respective longitudinal areas.

[0185] The first heating resistor R1 is set as a high heating portion 721 with a thin line width of the heating material and a large resistance in an area of ​​length d1 (for example, the short side dimension of JIS standard A5 size paper), so that the area generates heat with a high heat generation to the left and right based on the center (center reference line Lc) of the heating area along the long side direction. In addition, the low heating portion 722 is set as a heating material with a thick line width and a small resistance, so that the areas at the two ends of the heating area of ​​the high heating portion 721 do not generate heat.

[0186] The second heating resistor R2 is set as a high heating portion 721 with a thin line width of the heating material and a large resistance in an area of ​​length d2 (for example, the short side dimension of JIS standard B4 size paper), so that the area generates heat with a high heat generation to the left and right based on the center (center reference line Lc) of the heating area along the long side direction. In addition, the low heating portion 722 is set as a heating material with a thick line width and a small resistance, so that the areas at the two ends of the heating area of ​​the high heating portion 721 do not generate heat.

[0187] The third heating resistor R3 is set as a low heating portion 722 with a thick line width of the heating material and a small resistance in the region of length d2, so that the region does not generate heat to the left and right based on the center (center reference line Lc) of the heating region along the long side direction. In addition, the high heating portion 721 is set as a thin line width of the heating material and a large resistance, so that the regions at both ends of the heating region of the low heating portion 722 generate heat with a high calorific value.

[0188] In this example, the first heating resistor R1 , the second heating resistor R2 , and the third heating resistor R3 are all configured such that the high heating portion 721 is connected to the low heating portion 722 via the connecting heating portion 723 .

[0189] Thus, in this example, the second heating resistor R2 and the third heating resistor R3 are both formed by connecting the high heating portion 721 and the low heating portion 722, but the positional relationship between the high heating portion 721 and the low heating portion 722 in the long side direction is opposite to each other. Therefore, the heat generation of the second heating resistor R2 and the third heating resistor R3 in the long side direction is as follows: Fig.12 As shown, if the two are added together, a roughly uniform heating value can be obtained.

[0190] In addition, in this example, a contact region variable mechanism 90 ( Figure 3 , Figure 5 In this example, the minimum contact area CN selected when the fixing device 60 is started is mainly used. S The contact area CN with a wide width is usually selected during printing. L However, of course, the contact area CN may be changed more finely according to the physical properties and size of the medium S and used.

[0191] In this example, a surface temperature sensor SN (refer to Figure 3 ) can use three.

[0192] One of the surface temperature sensors SN1 detects the surface temperature of the fixing belt 61 corresponding to the medium passing area. In this example, one of the surface temperature sensors SN1 detects the surface temperature near the center reference line Lc in the fixing belt 61.

[0193] The other surface temperature sensor SN2 detects the temperature of an area of ​​the surface of the fixing belt 61 corresponding to the medium passing area, which is outside the short side dimension of the letter-sized paper and inside the short side dimension of the JIS standard B4 size.

[0194] The other surface temperature sensor SN3 detects the surface temperature of the fixing belt 61 corresponding to the medium non-passing region.

[0195] -Heating and pressurizing treatment of the fixing device-

[0196] Now, assuming that a printing instruction is issued from an operation panel (not shown), the control device 100 executes a series of image forming processes.

[0197] When the fixing device 60 receives a print instruction but the heating conditions of the fixing device 60 and the pressing conditions of the pressing roller 63 are not yet prepared, the fixing device 60 is started up.

[0198] Here, when it is determined that the control device 100 is in the activation state, the contact area variable mechanism 90 is used to narrow the contact area CN. That is, the contact area CN is set to the minimum contact area CN. S (refer to Fig.12 and Fig.13 (b)).

[0199] In this state, the control device 100 monitors the temperature information from the surface temperature sensor SN1 and simultaneously energizes the second heating resistor R2 and the third heating resistor R3 to heat the fixing belt 61 until the fixing belt 61 reaches a predetermined specified value Tm (equivalent to the temperature required for the fixing action).

[0200] Furthermore, in this case, Fig.12 As shown, the high heat generating portion 721 of the second heating resistor R2 and the third heating resistor R3 is included in the minimum contact area CN. S within the range.

[0201] In this startup operation, the high heat generating portion 721 of the second heating resistor R2 and the third heating resistor R3 is in the minimum contact area CN. S Since the fixing belt 61 is heated with a high heat, the heating process of the fixing belt 61 is efficiently performed in a short time.

[0202] At this time, the high heat generating portion 721 of the second heating resistor R2 and the third heating resistor R3 does not exceed the minimum contact area CN. S range, so the minimum contact area CN S The surrounding area will not be overheated.

[0203] In this example, the first heating resistor R1 is not used during the startup operation, so the high heat generation portion 721 of the first heating resistor R1 is not included in the minimum contact area CN. S It’s fine within the scope.

[0204] Next, when the start-up operation of the fixing device 60 is completed, the control device 100 sets the contact area CN to a wide state. That is, the contact area CN is set to a normal contact area CN with a wide width during printing. L (refer to Fig.13 In this example, the high heat generating portion 721 of the heating resistors R1, R2, and R3 is included in the wide normal contact area CN. L middle.

[0205] In this state, the control device 100 performs a fixing process suitable for printing. That is, while the temperature acquired by the surface temperature sensor SN1 is set to a certain value so that the medium passing area in the long side direction is in a good fixing state, the temperature acquired by the surface temperature sensor SN2 or the surface temperature sensor SN3 does not exceed the threshold value Tth, and the control is performed as follows so that the medium non-passing area in the long side direction does not exceed the heat resistance temperature of various components.

[0206] ■When printing on media larger than B4 size

[0207] (i) When the temperature acquired by the surface temperature sensor SN3 is equal to or lower than a certain threshold value Tth, the second heating resistor R2 and the third heating resistor R3 are simultaneously controlled to be turned on and off.

[0208] (ii) In cases other than (i), the third heating resistor R3 is in the OFF state, and the second heating resistor R2 is controlled to be turned on and off.

[0209] ■When printing on media smaller than B4 size,

[0210] (i) When the temperature acquired by the surface temperature sensor SN2 is equal to or lower than a certain threshold value Tth, the first heating resistor R1 and the second heating resistor R2 are simultaneously controlled to be turned on and off.

[0211] (ii) In cases other than (i), the second heating resistor R2 is always kept in the OFF state, and the first heating resistor R1 is controlled to be turned on and off.

[0212] ◎Implementation method 3

[0213] exist Fig.14 Detailed description is given of the main parts of the fixing device according to the third embodiment.

[0214] exist Fig.14 In the figure, the basic structure of the fixing device 60 includes: a fixing belt 61; a pressure roller 63, which is arranged to face the surface side of the fixing belt 61 and pressurizes the fixing belt 61; a facing pad 130, which is arranged to face the pressure roller 63 across the fixing belt 61 and forms a first contact area CN1 for the medium S to pass between the fixing belt 61 and the pressure roller 63; a heating component 140, which is arranged to contact the back side of a portion of the fixing belt 61 different from the first contact area CN1 and heats the back side of the fixing belt 61; a force spring 150 as a pressing member, which presses the heating component 140 toward the fixing belt 61 side; and a pressure adjustment mechanism 160, which changes the pressure state of the second contact area CN2 between the heating component 140 and the fixing belt 61.

[0215] In this example, the fixing belt 61 is formed of a cylindrical belt member, and is rotatably sandwiched in the first contact region CN1 between the pressure roller 63 and the opposing pad 130 .

[0216] Then, the pressure roller 63 is driven to rotate by receiving the driving force from the driving mechanism 170 , and the fixing belt 61 rotates following the pressure roller 63 .

[0217] Furthermore, in this example, the second contact region CN2 is provided at a position shifted by approximately 180° from the first contact region CN1 with respect to the fixing belt 61 .

[0218] Moreover, if Fig.15 As shown in the figure, the heating component 140 extends in the width direction of the fixing belt 61 and has a curved substrate 141 with a curved cross section. The curvature radius r1 (not shown) of the surface side of the curved substrate 141 is set shorter than the curvature radius r2 (not shown) of the inner surface of the fixing belt 61 in a free state. In addition, a plurality of (two in this example) heating resistors 142 (specifically 142a, 142b) are formed on the surface of the curved substrate 141, and an insulating protective layer 143 is stacked on the surface of the curved substrate 141 in a manner covering the heating resistors 142.

[0219] The heat generating component 140 is supported by a supporting member 145 , and the supporting member 145 is urged by an urging spring 150 , so that the heat generating component 140 is pressed toward the fixing belt 61 .

[0220] In this example, two heating resistors 142 (142a, 142b) extend in the longitudinal direction and are arranged side by side with a distance therebetween on the surface of the curved substrate 141. The two heating resistors 142 (142a, 142b) are configured as strip-shaped heating wires of the same width.

[0221] Furthermore, in this example, in the pressure adjustment mechanism 160, as shown in FIG. Fig.15 As shown, the base end of the force spring 150 is mounted on a movable plate 161 that can be raised and lowered, and an eccentric cam 162 is contacted and arranged at the lower part of the movable plate 161. The eccentric cam 162 is provided with a long diameter position RL and a short diameter position RS. In addition, the eccentric cam 162 can be rotated by a driving motor 163. If the movable plate 161 rises, the position of the base end of the force spring 150 rises accordingly, and the heat generating component 140 is pressed against the fixing belt 61.

[0222] In this example, the pressure adjustment mechanism 160 is intended to change the pressure state during the startup operation of the fixing device 60 and during printing, thereby changing the contact area of ​​the second contact area CN2 between the heat generating component 140 and the fixing belt 61 .

[0223] That is, when the fixing device 60 is started, the pressure adjustment mechanism 160 makes the short diameter position RS of the eccentric cam 162 contact the movable plate 161 to lower the position of the movable plate 161. Fig.16 As shown in (a) of FIG. 1 , the urging force of the urging spring 150 on the heat generating component 140 becomes weaker, and the contact area in the second contact area CN2 between the heat generating component 140 and the fixing belt 61 becomes narrower.

[0224] Therefore, at startup, in order to quickly raise the temperature of the fixing belt 61 to a predetermined temperature, the contact area is narrowed and the heat from the fixing belt 61 is not taken away. At the same time, the heat is accumulated in the fixing belt 61 by the heat generated by the heating resistor 142, thereby increasing the temperature of the fixing belt 61.

[0225] On the other hand, during normal printing, the pressure adjustment mechanism 160 makes the long diameter position RL of the eccentric cam 162 contact the movable plate 161 to raise the position of the movable plate 161. Fig.16 As shown in (b) of FIG. 1 , the urging force of the urging spring 150 on the heat generating component 140 becomes stronger, and the contact area in the second contact area CN2 between the heat generating component 140 and the fixing belt 61 becomes wider.

[0226] Thus, during normal printing, the contact area of ​​the second contact area CN2 becomes wider. Therefore, in addition to the heat generated by the heating resistor 142, a large amount of heat accumulated in the heating component 140 is also supplied to the fixing belt 61. Therefore, when the medium S passes through the first contact area CN1, the heat of the fixing belt 61 is taken away, but the temperature of the fixing belt 61 immediately rises due to the heat supplied from the heating component 140.

[0227] In this example, the pressure adjustment mechanism 160 presses the heat generating component 140 upward, but the present invention is not limited thereto, and the design may be modified as appropriate, for example, by pressing the heat generating component 140 in the lateral direction relative to the fixing belt 61 .

[0228] Furthermore, in the present embodiment, regarding the plurality of heating resistors 142 (142a, 142b), an example of a strip-shaped heating wire portion having the same width can be cited, but it is not limited to this. Similar to Embodiments 1 and 2, a high heating portion and a low heating portion having different line widths are provided relative to the heating resistor 142, thereby being able to control the heating state of the fixing belt 61 from the heating resistor 142 according to the change in the contact area of ​​the second contact area CN2.

[0229] (Note) (((1)))

[0231] A heating device, characterized by comprising:

[0232] A belt-shaped heated member that circulates and rotates;

[0233] a heat generating member disposed in contact with the back side of the heated member, extending in a direction intersecting with the rotation direction of the heated member and heating the heated member;

[0234] a pressurizing member that brings the heated member and the heat generating member into contact under a pressurized state, and contacts the heated member to form a contact region extending along the long side direction of the heat generating member; and

[0235] a pressurizing adjustment member for adjusting a pressurizing state based on the pressurizing member so as to change the width of the contact area in the short side direction;

[0236] The heating component comprises a plurality of heating resistors extending in the long side direction, a high heating portion having a narrow width and a high heat generation and a low heating portion having a wide width and a low heat generation are connected to the plurality of heating resistors, and for at least two of the plurality of heating resistors, the high heating portions are formed in different regions in the long side direction of the contact region,

[0237] When the minimum contact area with the smallest width in the short side direction of the contact area is formed by the pressure member, for the at least two heating resistors, the high heating part is included in the range of the minimum contact area, a part of the low heating part is included in the range of the minimum contact area, and the remaining part of the low heating part exceeds the range of the minimum contact area. (((2)))

[0239] The heating device according to (((1))) is characterized in that

[0240] The heating component comprises a first heating resistor and a second heating resistor extending in the longitudinal direction, a high heating portion having a narrow width and a high heating value and a low heating portion having a wide width and a low heating value being connected to the first heating resistor, and the high heating portion and the low heating portion are connected to the second heating resistor in a region different from that of the first heating resistor.

[0241] When the minimum contact area with the smallest width in the short side direction of the contact area is formed by the pressure member, the high heating parts of the first heating resistor and the second heating resistor are both included in the range of the minimum contact area, a part of the low heating part is included in the range of the minimum contact area, and the remaining part of the low heating part exceeds the range of the minimum contact area. (((3)))

[0243] The heating device according to (((1))) or (((2))) is characterized in that:

[0244] The pressurizing member includes a pressurizing member that is rotatably provided to face the heat generating member with the heated member interposed therebetween. (((4)))

[0246] The heating device according to (((1))) or (((2))) is characterized in that:

[0247] The pressurizing member includes a pressing component that presses the heat generating member against the heated member. (((5)))

[0249] The heating device according to any one of (((1))) to (((4))), characterized in that

[0250] The heated member contacts a heating target medium moving in the contact region or on the downstream side in the rotation direction of the contact region and heats the heating target medium.

[0251] The heat generating member includes the plurality of heat generating resistors, and the plurality of heat generating resistors are arranged so as to include a maximum width region in a direction intersecting with a moving direction of the heating target medium. (((6)))

[0253] The heating device according to (((5))) is characterized in that

[0254] The heat generating member includes the plurality of heat generating resistors, and the plurality of heat generating resistors heat the heating target medium moving about a center reference line passing through the center of a direction intersecting with a rotation direction of the heated member. (((7)))

[0256] The heating device according to (((2))) is characterized in that

[0257] The heated member heats a heating target medium that moves about a center reference line passing through the center of a direction intersecting the rotation direction of the heated member.

[0258] The first heating resistor, which is one of the plurality of heating resistors, forms the high heating portion in a region including the center in the longitudinal direction of the contact region, and forms the low heating portion near an end portion in the longitudinal direction sandwiching the high heating portion. (((8)))

[0260] The heating device according to (((7))) is characterized in that

[0261] The second heating resistor forms the low heating portion in a region corresponding to the high heating portion of the first heating resistor, and forms the high heating portion in a region corresponding to the low heating portion of the first heating resistor. (((9)))

[0263] The heating device according to (((1))) is characterized in that

[0264] The heated member heats a heating target medium that moves about a center reference line passing through the center of a direction intersecting the rotation direction of the heated member.

[0265] The heat generating component comprises first to third heat generating resistors,

[0266] The first heating resistor forms the high heat generating portion in a region including the center in the longitudinal direction of the contact region, and forms the low heat generating portion near the end in the longitudinal direction sandwiching the high heat generating portion.

[0267] The second heating resistor forms the low heating portion in a region corresponding to the high heating portion of the first heating resistor, and forms the high heating portion in a region corresponding to the low heating portion of the first heating resistor.

[0268] The third heating resistor forms the high heating portion in a region including the center in the longitudinal direction of the contact region and narrower than the high heating portion of the first heating resistor, and forms the low heating portion near the end in the longitudinal direction across the high heating portion. (((10)))

[0270] The heating device according to any one of (((1))) to (((9))) is characterized in that

[0271] The high heat generation portion and the low heat generation portion are connected via a connecting heat generation portion whose width dimension gradually changes. (((11)))

[0273] The heating device according to any one of (((1))) to (((10))) is characterized in that

[0274] The connected heat generating portion is formed in a mountain shape in which a width dimension changes linearly. (((12)))

[0276] The heating device according to any one of (((1))) to (((11))) is characterized in that

[0277] The heat generating member includes an elongated substrate and the plurality of heat generating resistors formed along a long side direction of the substrate. (((13)))

[0279] The heating device according to (((12))) is characterized in that

[0280] The heat generating member includes the plurality of heat generating resistors formed on a surface of the substrate on the heated member side along a longitudinal direction, and the plurality of heat generating resistors are covered with a heat-resistant protective layer. (((14)))

[0282] The heating device according to any one of (((1))) to (((13))) is characterized in that

[0283] The heated member contacts a heating target medium moving in the contact region or on the downstream side in the rotation direction of the contact region and heats the heating target medium.

[0284] When the heated member is heated without passing the heating target medium, the pressurizing member forms the minimum contact area.

[0285] The heat generating member generates heat from at least two heat generating resistors including the high heat generating portion within the minimum contact area among the plurality of heat generating resistors. (((15)))

[0287] The heating device according to (((14))) is characterized in that

[0288] When the heating medium is passed through to heat the heated member,

[0289] The pressing member forms a contact area having a width wider than the minimum contact area,

[0290] The heat generating member combines the plurality of heat generating resistors according to a width dimension in a direction intersecting with a moving direction of the heating target medium to generate heat. (((16)))

[0292] A heating treatment system, characterized by comprising:

[0293] a processing means for performing a predetermined processing on the heating target medium; and

[0294] The heating device according to any one of (((1))) to (((15))) heats the heating target medium processed by the processing member. (((17)))

[0296] The heating treatment system according to (((16))) is characterized in that:

[0297] The processing means is an image generating means for producing an unfixed image on the heating target medium.

[0298] The heating device is a fixing device that fixes the unfixed image formed on the heating target medium.

[0299] According to the heating device involved in (((1))), when a plurality of heating resistors are used as heating components and a heating contact area is formed between a strip-shaped heated component and the heating component, an excessive increase in temperature around the contact area can be suppressed without increasing the pressure load on the contact area.

[0300] According to the heating device involved in (((2))), when two heating resistors are used as heating components and a heating contact area is formed between a strip-shaped heated component and the heating component, an excessive increase in temperature around the contact area can be suppressed without increasing the pressure load on the contact area.

[0301] According to the heating device involved in (((3))), with respect to the method of heating the heating target medium in the contact area between the heated member and the heat generating member, it is possible to suppress an excessive increase in the temperature around the contact area without increasing the pressure load on the contact area.

[0302] According to the heating device involved in (((4))), relative to a method of heating the heating object medium at a position closer to the downstream side of the rotation direction of the heated member than the contact area between the heated member and the heat generating member, it is possible to suppress an excessive increase in the temperature around the contact area without increasing the pressure load on the contact area.

[0303] According to the heating device involved in (((5))), as a heat generating member, it is possible to efficiently heat a heating target medium of the maximum size that can be used.

[0304] According to the heating device involved in (((6))), as the heat generating member, it is possible to efficiently heat the heating target medium moving around the central reference line.

[0305] According to the heating device involved in (((7))), even for the heating target medium that moves around the center reference line, it is possible to effectively heat the heating target medium of various sizes.

[0306] According to the heating device according to (((8))), even in the embodiment in which the heat generating member has two heat generating resistors, heating target media of various sizes can be efficiently heated.

[0307] According to the heating device according to (((9))), even in the embodiment in which the heat generating member has three heat generating resistors, heating target media of various sizes can be efficiently heated.

[0308] According to the heating device involved in (((10))), compared with the case where there is no connected heat generating portion, the distribution of the heat generated by the high heat generating portion and the low heat generating portion in the long side direction of the contact area can be made more uniform.

[0309] According to the heating device involved in (((11))), the connected heat generating part can be simply configured compared with the connected heat generating part that changes in a curve.

[0310] According to the heating device involved in (((12))), an existing planar heat generating member can be used as the heat generating member.

[0311] According to the heating device involved in (((13))), compared with a method of forming a plurality of heating resistors on the opposite side of the heated component of the substrate, the plurality of heating resistors can be brought closer to the heated component, thereby obtaining a more appropriate distribution of heat while avoiding friction with the heated component.

[0312] According to the heating device according to (((14))), the heating process by the heating device can be appropriately performed without passing the heating target medium.

[0313] According to the heating device involved in (((15))), the heating target medium can be passed through and the heating treatment of the heating device can be appropriately performed.

[0314] According to the heating treatment system involved in (((16))), a heating treatment system including a heating device can be constructed, in which a plurality of heating resistors are used as heating components, and when a heating contact area is formed between a strip-shaped heated component and the heating component, an excessive increase in temperature around the contact area can be suppressed without increasing the pressure load on the contact area.

[0315] According to the heat treatment system involved in (((17))), it is possible to provide a heat treatment system that can appropriately heat a heating target medium on which an unfixed image is formed.

[0316] The above-mentioned embodiments of the present invention are provided for the purpose of illustration and description. In addition, the embodiments of the present invention do not fully and exhaustively include the present invention, and do not limit the present invention to the disclosed methods. Obviously, various modifications and changes are self-evident to those skilled in the art to which the present invention belongs. The present embodiment is selected and described in order to most easily understand the principles of the present invention and its application. Thus, other technicians in the art can understand the present invention through various variations optimized for specific uses assumed to be various embodiments. The scope of the present invention is defined by the above claims and their equivalents.

[0317] Explanation of symbols

[0318] 1-heated member, 2-heating member, 3-heating resistor (3a, 3b), 4-pressurizing member, 5-pressurizing adjusting member, 6-high heat generating portion, 7-low heat generating portion, 8-connecting heat generating portion, 10-processing member, 11-heating device, S-heating target medium, CN-contact area, CN S - Minimum contact area, Lc - center reference line.

Claims

1. A heating device, characterized in that: have: A belt-shaped heated member that rotates cyclically; a heat generating member disposed in contact with the back side of the heated member, extending in a direction intersecting with the rotation direction of the heated member and heating the heated member; a pressurizing member that brings the heated member and the heat generating member into contact under a pressurized state, and contacts the heated member to form a contact region extending along the long side direction of the heat generating member; and a pressurizing adjustment member for adjusting a pressurizing state based on the pressurizing member so as to change the width of the contact area in the short side direction; The heating component comprises a plurality of heating resistors extending in the long side direction, a high heating portion having a narrow width and a high heat generation and a low heating portion having a wide width and a low heat generation are connected to the plurality of heating resistors, and for at least two of the plurality of heating resistors, the high heating portions are formed in different regions in the long side direction of the contact region, When the minimum contact area with the smallest width in the short side direction of the contact area is formed by the pressure member, for the at least two heating resistors, the high heating part is included in the range of the minimum contact area, a part of the low heating part is included in the range of the minimum contact area, and the remaining part of the low heating part exceeds the range of the minimum contact area.

2. The heating device according to claim 1, characterized in that The heating component comprises a first heating resistor and a second heating resistor extending in the longitudinal direction, a high heating portion having a narrow width and a high heating value and a low heating portion having a wide width and a low heating value being connected to the first heating resistor, and the high heating portion and the low heating portion are connected to the second heating resistor in a region different from that of the first heating resistor. When the minimum contact area with the smallest width in the short side direction of the contact area is formed by the pressure member, the high heating parts of the first heating resistor and the second heating resistor are both included in the range of the minimum contact area, a part of the low heating part is included in the range of the minimum contact area, and the remaining part of the low heating part exceeds the range of the minimum contact area.

3. The heating device according to claim 1 or 2, characterized in that: The pressurizing member includes a pressurizing member that is rotatably provided to face the heat generating member with the heated member interposed therebetween.

4. The heating device according to claim 1 or 2, characterized in that: The pressurizing member includes a pressing component that presses the heat generating member against the heated member.

5. The heating device according to any one of claims 1 to 4, characterized in that: The heated member contacts a heating target medium moving in the contact region or on the downstream side in the rotation direction of the contact region and heats the heating target medium. The heat generating member includes the plurality of heat generating resistors, and the plurality of heat generating resistors are arranged so as to include a maximum width region in a direction intersecting with a moving direction of the heating target medium.

6. The heating device according to claim 5, characterized in that: The heat generating member includes the plurality of heat generating resistors, and the plurality of heat generating resistors heat the heating target medium moving about a center reference line passing through the center of a direction intersecting with a rotation direction of the heated member.

7. The heating device according to claim 2, characterized in that: The heated member heats a heating target medium that moves about a center reference line passing through the center of a direction intersecting the rotation direction of the heated member. The first heating resistor, which is one of the plurality of heating resistors, forms the high heating portion in a region including the center in the longitudinal direction of the contact region, and forms the low heating portion near an end portion in the longitudinal direction sandwiching the high heating portion.

8. The heating device according to claim 7, characterized in that: The second heating resistor forms the low heating portion in a region corresponding to the high heating portion of the first heating resistor, and forms the high heating portion in a region corresponding to the low heating portion of the first heating resistor.

9. The heating device according to claim 1, characterized in that: The heated member heats a heating target medium that moves about a center reference line passing through the center of a direction intersecting the rotation direction of the heated member. The heat generating component comprises a first heat generating resistor, a second heat generating resistor and a third heat generating resistor. The first heating resistor forms the high heat generating portion in a region including the center in the longitudinal direction of the contact region, and forms the low heat generating portion near the end in the longitudinal direction sandwiching the high heat generating portion. The second heating resistor forms the low heating portion in a region corresponding to the high heating portion of the first heating resistor, and forms the high heating portion in a region corresponding to the low heating portion of the first heating resistor. The third heating resistor forms the high heating portion in a region including the center in the longitudinal direction of the contact region and narrower than the high heating portion of the first heating resistor, and forms the low heating portion near the end in the longitudinal direction across the high heating portion.

10. The heating device according to any one of claims 1 to 9, characterized in that: The high heat generation portion and the low heat generation portion are connected via a connecting heat generation portion whose width dimension gradually changes.

11. The heating device according to any one of claims 1 to 10, characterized in that: The connected heat generating portion is formed in a mountain shape in which a width dimension changes linearly.

12. The heating device according to any one of claims 1 to 11, characterized in that: The heat generating member includes an elongated substrate and the plurality of heat generating resistors formed along a long side direction of the substrate.

13. The heating device according to claim 12, characterized in that: The heat generating member includes the plurality of heat generating resistors formed on a surface of the substrate on the heated member side along a longitudinal direction, and the plurality of heat generating resistors are covered with a heat-resistant protective layer.

14. The heating device according to any one of claims 1 to 13, characterized in that The heated member contacts a heating target medium moving in the contact region or on the downstream side in the rotation direction of the contact region and heats the heating target medium. When the heated member is heated without passing the heating target medium, the pressurizing member forms the minimum contact area. The heat generating member generates heat from at least two heat generating resistors including the high heat generating portion within the minimum contact area among the plurality of heat generating resistors.

15. The heating device according to claim 14, characterized in that When the heating medium is passed through to heat the heated member, The pressing member forms a contact area having a width wider than the minimum contact area, The heat generating member combines the plurality of heat generating resistors according to a width dimension in a direction intersecting with a moving direction of the heating target medium to generate heat.

16. A heating treatment system, characterized in that: have: a processing means for performing a predetermined processing on the heating target medium; and The heating device according to any one of claims 1 to 15 heats the heating target medium processed by the processing member.

17. The heating treatment system according to claim 16, characterized in that: The processing means is an image generating means for producing an unfixed image on the heating target medium. The heating device is a fixing device that fixes the unfixed image formed on the heating target medium.

Images