JP2021089416A - Heating member, heating device, and image forming apparatus - Google Patents

Abstract

To reduce variations in temperature over a longitudinal direction of a heating member.SOLUTION: When a connection part, of a plurality of connection parts G1, G2 to which conductors 62A to 62C and heating elements 59 are connected, which connects a heating element 59 with the conductors 62A, 62c arranged on one side in a short direction of a base material with respect to the heating element 59 is a first connection part G1, and a connection part which connects a heating element 59 with the conductor 62B arranged on the other side in the short direction of the base material with respect to the heating element 59 is a second connection part G2, and when the heating elements 59 are divided into a first zone A1 and a second zone A2 with a center line M in a longitudinal direction U of the heating elements 59 as a reference, at least one connecting zone of the first connection part G1 and second connection part G2 is different in some of the heating elements 59 and the heating element 59 other than those.SELECTED DRAWING: Figure 13

Description

The present invention relates to a heating member, a heating device and an image forming device.

For example, in an image forming apparatus such as a copying machine or a printer, a planar resistance heating element is used as a heating member used in a fixing device for fixing toner on paper by heat or a drying device for drying ink on paper. The heating member to have is known.

Patent Document 1 below discloses a heater provided with a resistance heating element, electrical contacts, a conductor pattern connecting these, and the like on a longitudinal substrate as a heating member used in a fixing device.

By the way, in a heater provided with a resistance heating element and a conductor pattern on a substrate, when the resistance heating element generates heat, a current flows through the conductor pattern, so that the conductor pattern also generates heat slightly. Therefore, strictly speaking, the heat generation distribution in the longitudinal direction of the entire heater is affected by the heat generation of the conductor pattern.

Therefore, the temperature distribution of the heater may vary due to the heat generation distribution of the conductor pattern. In particular, when the current flowing through the resistance heating element increases in order to increase the amount of heat generated in response to the increase in speed of the image forming apparatus, the amount of heat generated in the conductor pattern also increases, so that the influence of heat generated by the conductor pattern cannot be ignored. Therefore, in a device provided with such a heater, measures are required to enable the temperature distribution in the longitudinal direction to be set.

In order to solve the above problems, the present invention presents a plate-shaped base material having a longitudinal direction, a plurality of electrode portions provided on the base material, and a plurality of electrodes arranged along the longitudinal direction of the base material. A heating member including a heating element and a plurality of conductors provided on the base material and connecting the electrode portion and the heating element, and the heating elements adjacent to each other have an insulating region between them. Of a plurality of connecting portions that are arranged via and connect the conductor and the heating element, the conductor and the heating element that are arranged on one side in the lateral direction of the base material with respect to the heating element are connected. The connecting portion is used as the first connecting portion, and the connecting portion that connects the conductor arranged on the other side of the heating element in the lateral direction of the base material and the heating element is used as the second connecting portion. When each heating element is divided into a first area and a second area with reference to the center line in the longitudinal direction of each heating element, the first connection portion and the second connection portion It is characterized in that at least one of the connecting areas is different between some of the heating elements and the other heating elements.

According to the present invention, the temperature distribution in the longitudinal direction can be set.

It is a schematic block diagram of the image forming apparatus which concerns on embodiment of this invention. It is a schematic block diagram of the fixing device. It is a perspective view of the fixing device. It is an exploded perspective view of the fixing device. It is a perspective view of a heating device. It is an exploded perspective view of a heating device. It is a top view of a heater. It is an exploded perspective view of a heater. It is a perspective view which shows the state which a connector is connected to a heater. It is a top view of the heater which concerns on a comparative example. It is a figure which shows the heat generation amount of the feed line for each block when all resistance heating elements generate heat in the heater which concerns on a comparative example. It is a figure which shows the heat generation amount of the feed line for each block when only a part of the heat generating part heats up in the heater which concerns on a comparative example, and an unintended diversion occurs. It is a top view of the heater which concerns on 1st Embodiment of this invention. It is a figure which shows the heat generation amount of the feed line for each block when all resistance heating elements generate heat in the heater which concerns on 1st Embodiment. It is a figure which shows the heat generation amount of the feed line for each block when only a part of the heat generating part in the heater which concerns on 1st Embodiment generate heat and an unintended diversion occurs. It is a figure which compares and shows the heat generation distribution when all resistance heating elements generate heat, in a comparative example and 1st Embodiment. It is a figure which compares and shows the heat generation distribution in the case where only a part of the heat generating part generates heat and an unintended diversion occurs, in the comparative example and the 1st Embodiment. It is a top view of the heater which concerns on 2nd Embodiment of this invention. It is a figure which shows the heat generation amount of the feed line for each block when all resistance heating elements generate heat in the heater which concerns on 2nd Embodiment. It is a figure which shows the heat generation amount of the feed line for each block when only a part of the heat generating part in the heater which concerns on 2nd Embodiment generate heat and an unintended diversion occurs. It is a figure which compares and shows the heat generation distribution when all resistance heating elements generate heat in a comparative example, a 1st embodiment and a 2nd embodiment. It is a figure which compares and shows the heat generation distribution in the case where only a part of the heat generating part generates heat and an unintended diversion occurs in the comparative example, the 1st embodiment and the 2nd embodiment. It is a top view of the heater which concerns on 3rd Embodiment of this invention. It is a figure which shows the heat generation amount of the feed line for each block when all resistance heating elements generate heat in the heater which concerns on 3rd Embodiment. It is a figure which shows the heat generation amount of the feed line for each block when only a part of the heat generating part in the heater which concerns on 3rd Embodiment generate heat and an unintended diversion occurs. It is a figure which compares and shows the heat generation distribution when all resistance heating elements generate heat, in the comparative example and the 3rd Embodiment. It is a figure which compares and shows the heat generation distribution in the case where only a part of the heat generating part generates heat and an unintended diversion occurs, in the comparative example and the 3rd Embodiment. It is a top view of the heater which concerns on 4th Embodiment of this invention. It is a figure which shows the heat generation amount of the feed line for each block when all resistance heating elements generate heat in the heater which concerns on 4th Embodiment. It is a figure which shows the heat generation amount of the feed line for every block when only a part of the heat generating part heats up in the heater which concerns on 4th Embodiment, and an unintended diversion occurs. It is a figure which compares and shows the heat generation distribution when all resistance heating elements generate heat in a comparative example, a 3rd embodiment and a 4th embodiment. It is a figure which compares and shows the heat generation distribution in the case where only a part of the heat generating part generates heat and an unintended diversion occurs in the comparative example, the 3rd embodiment and the 4th embodiment. It is a top view of the heater which concerns on other comparative examples. It is a figure which shows the heat generation amount of the feed line for each block in the heater which concerns on a comparative example. It is a top view of the heater which concerns on 5th Embodiment of this invention. It is a figure which shows the calorific value of the feed line for each block in the heater which concerns on 5th Embodiment. It is a figure which compares and shows the heat generation distribution in the comparative example and the 5th Embodiment. It is a figure which shows the short side dimension of a heater and the short side dimension of a resistance heating element. It is a figure which shows the modification of the heater. It is a figure which shows the other modification of a heater. It is a figure which shows another modification of a heater. It is a figure which shows still another modification of a heater. It is a figure which shows still another modification of a heater. It is a figure which shows still another modification of a heater. It is a figure which shows the arrangement of the temperature detecting means. It is a figure which shows the structure of another fixing device. It is a figure which shows the structure of another fixing device. It is a figure which shows the structure of still another fixing device.

Hereinafter, the present invention will be described with reference to the accompanying drawings. In each drawing for explaining the present invention, components such as members or components having the same function or shape are designated by the same reference numerals as much as possible. Therefore, the description of the components once described will be omitted.

FIG. 1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention.

The image forming apparatus 100 shown in FIG. 1 includes four image forming units 1Y, 1M, 1C, and 1Bk, which are image forming units. The image forming units 1Y, 1M, 1C, and 1Bk are removable from the image forming apparatus main body 103. Further, each image forming unit 1Y, 1M, 1C, 1Bk has the same configuration except that it contains developeres of different colors of yellow, magenta, cyan, and black corresponding to the color separation components of the color image. Specifically, each image forming unit 1Y, 1M, 1C, 1Bk includes a photoconductor 2, a charging device 3, a developing device 4, and a cleaning device 5. The photoconductor 2 is a drum-shaped image carrier. The charging device 3 charges the surface of the photoconductor 2. The developing apparatus 4 supplies toner as a developer to the surface of the photoconductor 2 and forms a toner image on the surface of the photoconductor 2. The cleaning device 5 cleans the surface of the photoconductor 2.

Further, the image forming apparatus 100 includes an exposure apparatus 6, a paper feeding device 7, a transfer device 8, a fixing device 9, and a paper ejection device 10. The exposure apparatus 6 exposes the surface of each photoconductor 2 and forms an electrostatic latent image on the surface of each photoconductor 2. The paper feeding device 7 supplies the paper P as a recording medium. The transfer device 8 transfers the toner image formed on each photoconductor 2 to the paper P. The fixing device 9 fixes the toner image transferred to the paper P. The paper ejection device 10 ejects the paper P to the outside of the apparatus.

The transfer device 8 includes an intermediate transfer belt 11, four primary transfer rollers 12, and a secondary transfer roller 13. The intermediate transfer belt 11 is an endless intermediate transfer body stretched by a plurality of rollers. The four primary transfer rollers 12 are primary transfer members that transfer the toner image on each photoconductor 2 to the intermediate transfer belt 11. Each of the primary transfer rollers 12 is in contact with the photoconductor 2 via the intermediate transfer belt 11. As a result, the intermediate transfer belt 11 and each photoconductor 2 come into contact with each other, and a primary transfer nip is formed between them. The secondary transfer roller 13 is a secondary transfer member that transfers the toner image transferred on the intermediate transfer belt 11 to the paper P. The secondary transfer roller 13 is in contact with one of the rollers that stretches the intermediate transfer belt 11 via the intermediate transfer belt 11. As a result, a secondary transfer nip is formed between the secondary transfer roller 13 and the intermediate transfer belt 11.

Further, in the image forming apparatus 100, a paper conveying path 14 for conveying the paper P sent out from the paper feeding device 7 is formed. A pair of timing rollers 15 are provided on the way from the paper feeding device 7 to the secondary transfer nip (secondary transfer roller 13) in the paper transport path 14.

Next, the printing operation of the image forming apparatus will be described with reference to FIG.

When the printing operation is started, in each of the image forming units 1Y, 1M, 1C, and 1Bk, the photoconductor 2 is rotationally driven clockwise in FIG. 1, and the charging device 3 causes the surface of the photoconductor 2 to have a uniform high potential. Is charged. Next, the exposure device 6 exposes the surface of each photoconductor 2 based on the image information of the document read by the document reader or the print information sent from the terminal. As a result, the potential of the exposed portion is lowered and an electrostatic latent image is formed. Then, toner is supplied from the developing device 4 to the electrostatic latent image, and a toner image is formed on each photoconductor 2.

When the toner image formed on each photoconductor 2 reaches the primary transfer nip (position of the primary transfer roller 12) as each photoconductor 2 rotates, the intermediate transfer belt is rotationally driven counterclockwise in FIG. It is transferred to 11 so as to sequentially overlap. Then, the toner image transferred onto the intermediate transfer belt 11 is conveyed to the secondary transfer nip (position of the secondary transfer roller 13) as the intermediate transfer belt 11 rotates, and is conveyed at the secondary transfer nip. Transferred to paper P. This paper P is supplied from the paper feeding device 7. The paper P supplied from the paper feeding device 7 is temporarily stopped by the timing roller 15. After that, the paper P is conveyed to the secondary transfer nip at the timing when the toner image on the intermediate transfer belt 11 reaches the secondary transfer nip. Thus, a full-color toner image is supported on the paper P. Further, after the toner image is transferred to the paper P, the toner remaining on each photoconductor 2 is removed by each cleaning device 5.

The paper P on which the toner image is transferred is conveyed to the fixing device 9, and the toner image is fixed on the paper P by the fixing device 9. After that, the paper P is ejected to the outside of the output device 10 to complete a series of printing operations.

Hereinafter, the configuration of the fixing device 9 will be described in detail.

As shown in FIG. 2, the fixing device 9 according to the present embodiment includes a fixing belt 20, a pressure roller 21, and a heating device 19. The heating device 19 is a device that heats the fixing belt 20. The heating device 19 includes a heater 22, a heater holder 23, a stay 24, and the like.

The fixing belt 20 is an endless belt member as a fixing member. The fixing belt 20 has, for example, a tubular substrate made of polyimide (PI) having an outer diameter of 25 mm and a thickness of 40 to 120 μm. A mold release layer is formed on the outermost surface layer of the fixing belt 20 in order to enhance durability and ensure mold release. The release layer has a thickness of, for example, 5 to 50 μm, and is manufactured from a fluorine-based resin containing PFA, PTFE, or the like. An elastic layer may be provided between the substrate and the release layer. The elastic layer has, for example, a thickness of 50 to 500 μm and is manufactured of rubber or the like. Further, the substrate of the fixing belt 20 is not limited to polyimide, and may be a heat-resistant resin such as PEEK, or a metal substrate such as nickel (Ni) or SUS. The inner peripheral surface of the fixing belt 20 may be coated with polyimide, PTFE or the like as a sliding layer.

The pressure roller 21 is an opposing member that contacts the outer peripheral surface of the fixing belt 20 to form a nip portion N. The pressure roller 21 is, for example, a roller having an outer diameter of 25 mm. Further, the pressure roller 21 has a solid iron core metal 21a, an elastic layer 21b formed on the surface of the core metal 21a, and a release layer 21c formed on the outside of the elastic layer 21b. ing. The elastic layer 21b is made of silicone rubber. The thickness of the elastic layer 21b is, for example, 3.5 mm. It is desirable that the release layer 21c be provided on the surface of the elastic layer 21b in order to improve the releasability. The release layer 21c is, for example, a fluororesin layer having a thickness of about 40 μm.

The pressure roller 21 and the fixing belt 20 are pressed against each other by a spring as an urging member, which will be described later. As a result, the nip portion N is formed between the fixing belt 20 and the pressure roller 21. Further, the pressure roller 21 is a drive roller that is rotationally driven by transmitting a driving force from a driving means provided in the image forming apparatus main body. On the other hand, the fixing belt 20 is driven to rotate as the pressure roller 21 rotates. When the fixing belt 20 rotates, the fixing belt 20 slides with respect to the heater 22. In order to improve the slidability of the fixing belt 20 at this time, a lubricant such as oil or grease may be interposed between the heater 22 and the fixing belt 20.

The heater 22 is a planar heating member. The heater 22 is provided in a longitudinal direction over the rotation axis direction or the longitudinal direction (hereinafter, referred to as “belt longitudinal direction”) of the fixing belt 20. Further, the heater 22 is in contact with the inner peripheral surface of the fixing belt 20 at a position corresponding to the pressure roller 21. The heater 22 is a substantially rectangular flat plate, and its long side is along the longitudinal direction of the belt. The heater 22 has a plate-shaped base material 50, a first insulating layer 51, a conductor layer 52, and a second insulating layer 53. Further, the conductor layer 52 has a heat generating portion 60. The first insulating layer 51 is provided on the base material 50, the conductor layer 52 is provided on the first insulating layer 51, and the second insulating layer 53 is provided on the conductor layer 52. That is, in the present embodiment, the base material 50, the first insulating layer 51, the conductor layer 52 (heat generating portion 60), and the second insulating layer 53 are laminated in this order toward the fixing belt 20 side (nip portion N side). ing. Therefore, the heat generated from the heat generating portion 60 is transferred to the fixing belt 20 via the second insulating layer 53.

Unlike the present embodiment, the heat generating portion 60 may be provided on the side (heater holder 23 side) opposite to the fixing belt 20 side of the base material 50. In that case, the heat of the heat generating portion 60 is transferred to the fixing belt 20 via the base material 50. Therefore, it is desirable that the base material 50 is made of a material having high thermal conductivity, such as aluminum nitride. Further, in the configuration of the heater 22 according to the present embodiment, an insulating layer may be further provided on the surface of the base material 50 opposite to the fixing belt 20 (heater holder 23 side).

The heater 22 may come into contact with the fixing belt 20 indirectly via a non-contact or low friction sheet or the like. However, in order to increase the heat transfer efficiency to the fixing belt 20, it is preferable that the heater 22 comes into direct contact with the fixing belt 20 as in the present embodiment. Further, the heater 22 may come into contact with the outer peripheral surface of the fixing belt 20. When the surface in contact with the heater 22 is the inner peripheral surface of the fixing belt 20 as in the present embodiment, it is possible to avoid scratches on the outer peripheral surface of the fixing belt 20 due to the contact with the heater 22, and the fixing quality is improved. The decrease can be suppressed.

The heater holder 23 and the stay 24 are arranged inside the fixing belt 20. The heater holder 23 is a holding member that holds the heater 22. Further, the stay 24 is a reinforcing member that reinforces the heater holder 23 in the longitudinal direction. The stay 24 is a metal channel material, and both end portions of the stay 24 are supported by both side wall portions of the fixing device 9. Further, the stay 24 is in contact with the surface of the heater holder 23 opposite to the heater 22 side. As a result, the heater holder 23 is supported by the stay 24. Further, since the heater 22 and the heater holder 23 are held without being significantly bent with respect to the pressing force of the pressurizing roller 21, a nip portion N is formed between the fixing belt 20 and the pressurizing roller 21.

The heater holder 23 tends to become hot due to the heat of the heater 22. Therefore, it is desirable that the heater holder 23 is made of a heat-resistant material. For example, when the heater holder 23 is manufactured of a heat-resistant resin having low thermal conductivity including LCP or PEEK, heat transfer from the heater 22 to the heater holder 23 is suppressed and the fixing belt 20 can be heated efficiently.

When the printing operation is started, electric power is supplied to the heater 22, so that the heat generating portion 60 generates heat and the fixing belt 20 is heated. Further, the pressure roller 21 is rotationally driven, and the fixing belt 20 starts driven rotation. Then, in a state where the temperature of the fixing belt 20 reaches a predetermined target temperature (fixing temperature), as shown in FIG. 2, the paper P carrying the unfixed toner image is formed by the fixing belt 20 and the pressure roller 21. It is conveyed to the space (nip portion N). As a result, the unfixed toner image is heated and pressurized and fixed on the paper P.

FIG. 3 is a perspective view of the fixing device, and FIG. 4 is an exploded perspective view thereof.

As shown in FIGS. 3 and 4, the device frame 40 of the fixing device 9 includes a first device frame 25 and a second device frame 26. The first device frame 25 has a pair of side wall portions 28 and a front wall portion 27. On the other hand, the second device frame 26 has a rear wall portion 29. The pair of side wall portions 28 are arranged on one end side and the other end side in the longitudinal direction of the belt. Both side wall portions 28 support both ends of the fixing belt 20, the pressure roller 21, and the heating device 19. A plurality of engaging protrusions 28a are provided on each side wall portion 28. The first device frame 25 and the second device frame 26 are assembled by engaging the engaging protrusions 28a with the engaging holes 29a provided in the rear wall portion 29.

Further, each side wall portion 28 is provided with an insertion groove 28b for inserting the rotation shaft of the pressure roller 21 and the like. The insertion groove 28b opens on the rear wall portion 29 side. The side opposite to the rear wall portion 29 side of the insertion groove 28b is an abutting portion that does not open. A bearing 30 that supports the rotating shaft of the pressure roller 21 is provided at the end on the abutting portion side. By mounting both ends of the rotating shaft of the pressure roller 21 on the bearing 30, the pressure roller 21 is rotatably supported by the wall portions 28 on both sides.

Further, a drive transmission gear 31 as a drive transmission member is provided on one end side of the rotation shaft of the pressure roller 21. The drive transmission gear 31 is exposed to the outside of the side wall portion 28 in a state where the pressure roller 21 is supported by the side wall portions 28. As a result, when the fixing device 9 is mounted on the image forming apparatus main body, the drive transmission gear 31 is connected to the gear provided on the image forming apparatus main body, and the driving force can be transmitted from the drive source to the pressurizing roller 21. Become. The drive transmission member for transmitting the driving force to the pressure roller 21 is not limited to the drive transmission gear 31, and may be a pulley for tensioning the drive transmission belt, a coupling mechanism, or the like.

A pair of support members 32 are provided at both ends of the heating device 19 in the longitudinal direction. The pair of support members 32 support the fixing belt 20, the heater holder 23, the stay 24, and the like. Each support member 32 is provided with a guide groove 32a. The support member 32 is assembled to the side wall portion 28 by allowing the guide groove 32a to enter along the edge of the insertion groove 28b of the side wall portion 28.

Further, a pair of springs 33 as urging members are provided between each support member 32 and the rear wall portion 29. The fixing belt 20 is pressed against the pressure roller 21 by each spring 33 urging the stay 24 and the support member 32 toward the pressure roller 21. As a result, a nip portion is formed between the fixing belt 20 and the pressure roller 21.

Further, as shown in FIG. 4, a hole 29b is provided on one end side in the longitudinal direction of the rear wall portion 29 constituting the second device frame 26. The hole portion 29b is a positioning portion for positioning the fixing device main body with respect to the image forming device main body. On the other hand, the image forming apparatus main body is provided with a protrusion 101 as a positioning portion. The protrusion 101 is inserted into the hole 29b of the fixing device 9, so that the protrusion 101 and the hole 29b are fitted together. As a result, the fixing device main body is positioned in the belt longitudinal direction with respect to the image forming device main body. A positioning portion is not provided on the end side opposite to the end side where the hole portion 29b of the rear wall portion 29 is provided. Therefore, even if the fixing device main body expands and contracts in the longitudinal direction of the belt due to the temperature change, the expansion and contraction of the fixing device main body is not restricted, and distortion of the fixing device main body is suppressed.

FIG. 5 is a perspective view of the heating device 19, and FIG. 6 is an exploded perspective view thereof.

As shown in FIGS. 5 and 6, a rectangular accommodating recess 23a for accommodating the heater 22 is provided on the surface of the heater holder 23 on the fixing belt side (the surface on the front side in FIGS. 5 and 6). .. The accommodating recess 23a is formed to have substantially the same shape and size as the heater 22. However, the longitudinal dimension L2 of the accommodating recess 23a is set to be slightly longer than the longitudinal dimension L1 of the heater 22. As described above, since the accommodating recess 23a is formed slightly longer than the heater 22, even if the heater 22 extends in the longitudinal direction due to thermal expansion, the heater 22 and the accommodating recess 23a do not interfere with each other. Further, in a state where the heater 22 is housed in the housing recess 23a, the heater 22 is held so as to be sandwiched together with the heater holder 23 by the connector. The connector is a power feeding member described later for supplying electric power to the heater 22.

The pair of support members 32 have a C-shaped belt support portion 32b, a flange-shaped belt regulation portion 32c, and a support recess 32d. Each belt support portion 32b is inserted inside both ends of the fixing belt 20 in the longitudinal direction. As a result, the fixing belt 20 is supported by each belt support portion 32b in a so-called free belt system (when the fixing belt 20 does not rotate, basically no tension is generated in the fixing belt 20). On the other hand, each belt restricting portion 32c is not inserted inside the fixing belt 20, but is arranged so as to face the end portion in the longitudinal direction of the fixing belt 20. As a result, even if the fixing belt 20 moves in one direction in the longitudinal direction, the movement (shifting) of the fixing belt 20 is restricted by the contact of the longitudinal end portion of the fixing belt 20 with the belt regulating portion 32c. In each of the support recesses 32d, portions near both ends of the heater holder 23 and the stay 24 in the longitudinal direction are inserted. As a result, the heater holder 23 and the stay 24 are supported by the pair of support members 32.

As shown in FIGS. 5 and 6, a positioning recess 23e as a positioning portion is provided on one end side in the longitudinal direction of the heater holder 23. By fitting the fitting portion 32e of the support member 32 shown on the left side of FIGS. 5 and 6 into the positioning recess 23e, the heater holder 23 and the support member 32 are positioned in the belt longitudinal direction. On the other hand, the support member 32 shown on the right side of FIGS. 5 and 6 is not provided with the fitting portion 32e. Therefore, on the right side of the drawing, the support member 32 is not positioned in the belt longitudinal direction with respect to the heater holder 23. In this way, since the heater holder 23 is positioned with respect to the support member 32 only on one side in the belt longitudinal direction, expansion and contraction of the heater holder 23 in the belt longitudinal direction due to a temperature change is allowed.

Further, as shown in FIG. 6, step portions 24a are provided on both end sides of the stay 24 in the longitudinal direction. Each step portion 24a abuts on the support member 32 to regulate the movement of the stay 24 with respect to the support member 32 in the longitudinal direction. However, at least one of these stepped portions 24a is arranged with respect to the support member 32 via a gap (play). In this way, by arranging at least one step portion 24a with respect to the support member 32 via the gap, expansion and contraction of the stay 24 in the belt longitudinal direction due to a temperature change is allowed.

FIG. 7 is a plan view of the heater 22, and FIG. 8 is an exploded perspective view thereof.

As shown in FIG. 8, the heater 22 has a base material 50, a first insulating layer 51, a conductor layer 52, and a second insulating layer 53. The first insulating layer 51 is provided on the base material 50, the conductor layer 52 is provided on the first insulating layer 51, and the second insulating layer 53 is provided on the conductor layer 52.

The base material 50 is a longitudinal plate material made of a metal material including stainless steel (SUS), iron, aluminum, and the like. Further, as a material for producing the base material 50, in addition to a metal material, ceramic, glass or the like can also be used. When the base material 50 is manufactured of an insulating material containing ceramic or the like, the first insulating layer 51 between the base material 50 and the conductor layer 52 can be omitted. On the other hand, the metal material has excellent durability against rapid heating and is easy to process. Therefore, the metal material is suitable for cost reduction. Among the metal materials, aluminum or copper is particularly preferable because it has high thermal conductivity and is less likely to cause temperature unevenness. Further, stainless steel has an advantage that a base material can be manufactured at a lower cost than aluminum or copper.

The insulating layers 51 and 53 are manufactured of an insulating material including heat-resistant glass and the like. Further, the material for producing each of the insulating layers 51 and 53 may be ceramic, polyimide (PI) or the like.

The conductor layer 52 has a heat generating portion 60, a plurality of electrode portions 61, and a plurality of feeder lines 62. Further, the heating unit 60 has a plurality of resistance heating elements 59. The plurality of feeder lines 62 electrically connect each resistance heating element 59 and each electrode portion 61.

The resistance heating element 59 is a conductive portion having a higher resistance value than the feeder line 62. The resistance heating element 59 is applied to the base material 50 or the first insulating layer 51 by screen printing a paste containing, for example, silver palladium (AgPd) and glass powder, and then the base material 50 is fired. Formed by The material for producing the resistance heating element 59 may be a resistance material containing at least one of a silver alloy (AgPt) and ruthenium oxide (RuO _2).

The feeder line 62 is manufactured by a conductor having a resistance value smaller than the resistance value of the resistance heating element 59. The material for manufacturing the feeder line 62 and the electrode portion 61 is silver (Ag), silver palladium (AgPd), or the like. The feeder line 62 and the electrode portion 61 are formed by screen-printing such a material on the base material 50 or the first insulating layer 51.

As shown in FIG. 7, the resistance heating elements 59 are arranged so as to be arranged in a line along the longitudinal direction U (hereinafter, referred to as “base material longitudinal direction”) of the base material 50 at intervals from each other. .. Therefore, an insulating region F (second insulating layer 53) is interposed between adjacent resistance heating elements 59. Further, each resistance heating element 59 is electrically connected to any two of the three electrode portions 61. Specifically, in the present embodiment, each resistance heating element 59 other than both ends has a first feeder line (first conductor) with respect to the first electrode portion 61A provided on one end side in the longitudinal direction U of the base material. ) They are connected in parallel via 62A. Further, each resistance heating element 59 other than both ends is parallel to the second electrode portion 61B provided on the other end side in the longitudinal direction U of the base material via the second feeder line (second conductor) 62B. It is connected to the. On the other hand, the resistance heating elements 59 at both ends are not connected to the first electrode portion 61A. Each resistance heating element 59 at both ends has a third feeder line (third) with respect to a third electrode portion 61C (separate from the first electrode portion 61A) provided on one end side in the longitudinal direction U of the base material. Conductor) 62C is connected in parallel. Further, each resistance heating element 59 at both ends is connected in parallel to the second electrode portion 61B via a second feeder line 62B, like the other resistance heating elements 59.

In the present embodiment, since the connection structure between each resistance heating element 59 and each electrode portion 61 is the above-mentioned connection structure, the first heating portion 60A and the second heating portion 60B are connected to each other. Can generate heat independently. Here, the first heating unit 60A is a heating element having each resistance heating element 59 other than both ends, and the second heating unit 60B is a heating unit having each resistance heating element 59 at both ends. Specifically, when a voltage is applied to the first electrode portion 61A and the second electrode portion 61B and a potential difference is generated between the two electrode portions 61A and 61B, a current flows through each resistance heating element 59 other than both ends, and the first electrode portion 61A and the second electrode portion 61B are charged. Only the heat generating portion 60A of No. 1 generates heat. Further, when a voltage is applied to the third electrode portion 61C and the second electrode portion 61B and a potential difference is generated between the two electrode portions 61C and 61B, a current flows through each resistance heating element 59 at both ends, so that the second electrode portion 61C and the second electrode portion 61B are second. Only the heat generating portion 60B generates heat. Further, when a voltage is applied to all the electrode portions 61A to 61C, both (all) resistance heating elements 59 of the first heat generating portion 60A and the second heating portion 60B generate heat. For example, when a paper having a relatively small width of A4 size (passing width: 210 mm) or less passes through the fixing device, only the first heat generating portion 60A generates heat. On the other hand, when a paper having a relatively large width of A3 size (passing width: 297 mm) or more passes through the fixing device, the second heat generating portion 60B also generates heat in addition to the first heat generating portion 60A. As a result, a heat generating region corresponding to the paper width can be obtained.

FIG. 9 is a perspective view showing a state in which the connector 70 is connected to the heater 22.

As shown in FIG. 9, the connector 70 has a resin housing 71 and a plurality of contact terminals 72. Each contact terminal 72 is a leaf spring and is provided on the housing 71. Further, a harness 73 for power supply is connected to each contact terminal 72.

As shown in FIG. 9, the connector 70 is attached so as to sandwich the heater 22 and the heater holder 23 together from the front side and the back side. In this state, the contact portion 72a at the tip of each contact terminal 72 elastically contacts (presses) the corresponding electrode portion 61, and the heat generating portion 60 is connected to the power supply provided in the image forming apparatus via the connector 70. It is electrically connected. As a result, electric power can be supplied from the power source to the heat generating unit 60. Further, the connector 70 is similarly connected to the electrode portion 61 on the opposite side of the electrode portion 61 shown in FIG. In addition, in order to secure the connection between each electrode portion 61 and the connector 70, at least a part of each electrode portion 61 is not covered with the second insulating layer 53 and is exposed (see FIG. 7).

Here, the temperature variation (temperature distribution deviation) that occurs in the heater will be described based on the comparative example shown in FIG.

The heater 220 according to the comparative example shown in FIG. 10 has a plurality of resistance heating elements 590, three electrode portions 610A to 610C, and a plurality of feeder lines 620A to 620C, similarly to the heater 22 according to the above-described embodiment. doing. Each resistance heating element 590, each electrode portion 610A to 610C, and each feeder line 620A to 620C are provided on a longitudinal base material 500. Further, each resistance heating element 590 and each electrode portion 610A to 610C are electrically connected via a plurality of feeder lines 620A to 620C. In FIG. 10, the first insulating layer provided between the base material 500 and the resistance heating element 590 and the second insulating layer covering the resistance heating element 590 are omitted. The connection structures of the resistance heating element 590, the electrode portions 61A to 61C, and the feeder lines 62A to 62C are basically the same as those in the above-described embodiment. Therefore, in the comparative example, each resistance heating element 590 (first heating element 600A) other than both ends and each resistance heating element 590 (second heating unit 600B) at both ends can generate heat independently of each other. The differences between the comparative example and the embodiment of the present invention will be described later.

By the way, in the heater as in the comparative example, when the resistance heating element generates heat, the current flows to the feeder line, so that a slight amount of heat is generated also in the feeder line. Therefore, the heat generation distribution of the feeder line affects the temperature distribution of the heater, and the temperature distribution of the heater may vary. In particular, as the speed of the image forming apparatus increases, when the current flowing through the heating element increases in order to increase the amount of heat generated, the amount of heat generated in the feeder also increases, so that the influence of heat generated in the feeder cannot be ignored.

Based on FIG. 11, the heat generated in each feeder line 620A to 620C when the heater 220 according to the comparative example generates heat will be described.

In FIG. 11, when a current of 20% flows through all the resistance heating elements 590, the amount of heat generated by each feeder line 620A to 620C generated in each block partitioned by each resistance heating element 590 and the amount of heat generated thereof. Shows the total value. Here, the direction Y (see FIG. 10) that intersects the base material longitudinal direction U along the surface of the base material 500 on which the resistance heating element 590 is provided is referred to as a "base material short side direction". In each of the feeder lines 620A to 620C shown in FIG. 11, since the portion extending in the lateral direction Y of the base material is short, the amount of heat generated in the portion extending in the lateral direction Y of the base material is small. Therefore, the calorific value in the portion extending in the lateral direction Y of the base material is ignored, and only the calorific value in the portion extending in the longitudinal direction U of the base material is calculated. Further, since the calorific value (W) is represented by the following formula (1), the calorific value shown in the table of FIG. 11 is calculated as the square of the current (I) flowing through each feeder for convenience. Therefore, the calculated calorific value is a simply calculated value and is different from the actual calorific value.

The method of calculating the calorific value will be described by taking the first block and the second block in FIG. 11 as an example. For example, in the first block in FIG. 11, the current flowing through the first feeder line 620A is 100%, and the current flowing through the third feeder line 620C is 20%. Therefore, in the first block, 10400 (10000 + 400), which is the sum of the squares of the currents flowing through the feeder lines 620A and 620C, is the total calorific value. Further, in the second block in FIG. 11, the current flowing through the first feeder line 620A is 80%, the current flowing through the second feeder line 620B is 20%, and the current flowing through the third feeder line 620C is 20%. Is. Therefore, in the second block, 7200 (6400 + 400 + 400), which is the sum of the squares of the currents flowing through the feeder lines 620A to 620C, is the total calorific value. Further, in the other blocks, the calorific value is calculated in the same manner.

The graph in FIG. 11 shows the total calorific value of each block on the vertical axis. As can be seen from this graph, the total heat generation amount of the feeder line is large in the blocks on both ends and small in the block on the center side, and the heat generation distribution of the feeder line varies. Therefore, if the heat generation distribution of the heater also varies due to the variation in the heat generation distribution of the feeder line, gloss unevenness may occur in the fixed image and the image quality may deteriorate.

Further, the temperature variation caused by the heat generation of the feeder line occurs not only when all the resistance heating elements generate heat (example shown in FIG. 11) but also when some resistance heating elements generate heat. Can be. In particular, when an unintended diversion occurs in the feeder line due to the miniaturization of the heater or the speeding up of the image forming apparatus, there is a possibility that the temperature variation becomes remarkable. Unintended diversion is likely to occur when the resistance value of the feeder increases as a result of reducing the width of the feeder in the lateral direction of the heater in response to the miniaturization of the heater. Further, even when the resistance value of the resistance heating element is reduced in order to increase the heat generation amount of the resistance heating element in accordance with the speeding up of the image forming apparatus, unintended flow separation is likely to occur. That is, when the resistance value of the feeding line increases, the resistance value of the resistance heating element decreases, or both of them cause the resistance value of the feeding line and the resistance value of the resistance heating element to be relatively close to each other. , There is a possibility that current can flow in the path where current did not flow until now (unintended diversion may occur).

Specifically, FIG. 12 shows an example in which an unintended diversion occurs when the resistance value of the feeder line and the resistance value of the resistance heating element are relatively close to each other in the heater according to the comparative example. As shown in FIG. 12, in this example, a current of 20% is flowing through the first heat generating portion 600A. However, in the second resistance heating element 590 from the left in the figure, a part (5%) of the current passing through the resistance heating element 590 is at the branch portion X of the second feeder line 620A. The current flows to the side opposite to the electrode portion 610B side of No. 2 (left side in the figure), and a diversion occurs. A part of the separated current passes through the leftmost resistance heating element 590 in FIG. 12 and reaches the third electrode portion 610C. Then, a part of the current passes through the third feeder line 620C, reaches the resistance heating element 590 at the right end, and joins the second feeder line 620B.

The table and graph in FIG. 12 show the amount of heat generated in each feeder line 620A to 620C for each block when an unintended diversion occurs, and the total value thereof. In this example, when a current flows evenly by 20% to each resistance heating element 590 of the first heating unit 600A, a block that generates heat assuming that a part of the current is divided by 5% in the branch portion X. The amount of heat generated by each feeder line 620A to 620C is calculated for each (second block to sixth block). The calorific value calculation method is the same as the method described in the example shown in FIG.

As shown in the table and graph in FIG. 12, in this case as well, the total heat generation amount of the feeder line is large in the blocks on both ends, and conversely, the total heat generation amount of the feeder line is small in the block on the center side. The heat generation distribution of is uneven. Therefore, due to such variations in the temperature distribution of the feeder lines, gloss unevenness may occur in the fixed image, and the image quality may deteriorate.

Therefore, in the embodiment of the present invention, the following measures are taken in order to suppress the variation in temperature in the longitudinal direction of the heater as described above.

FIG. 13 is a plan view of the heater 22 according to the above-described embodiment of the present invention (first embodiment).

The heater 22 shown in FIG. 13 has a different connection position of the feeder line to a part of the resistance heating elements as compared with the heater 220 according to the comparative example shown in FIG. Here, in FIGS. 10 and 13, among the plurality of connection portions of the feeder line connected to the resistance heating element, the resistance heating element 59 (590) is arranged on one side of the base material lateral direction Y. The connection portion G1 is referred to as a "first connection portion". Further, the connecting portion G2 arranged on the other side of the resistance heating element 59 (590) in the lateral direction Y of the base material is referred to as a "second connecting portion". That is, each connection portion G1 of the first feeder line 62A (620A) and the third feeder line 62C (620C) to the resistance heating element 59 (590) is referred to as a "first connection portion", and the resistance heating element 59 (590) is used. ), The connection portion G2 of the second feed line 62B (620B) is referred to as a “second connection portion”. In addition, in FIGS. 10 and 13, the third feeder line 62C connected to the leftmost resistance heating element 59 (590) is different from the other feeder lines 62A and 62c in the direction Y in the lateral direction of the base material. It extends so as to bend from one side (upper side) to the other side (lower side). However, the connecting portion G1 of the feeder line 62C and a portion in the vicinity thereof are arranged on one side (upper side) of the base material lateral direction Y like the connecting portion G1 of the other feeder lines 62A and 62C. Therefore, it is used as the first connection part.

Further, the "first connection portion" and the "second connection portion" may be defined with reference to the direction of the current flowing through the resistance heating element. That is, the connection portion G1 arranged on the upstream side (one side) in the direction in which the current flows is referred to as the "first connection portion", and the connection portion G2 arranged on the downstream side (the other side) in the direction in which the current flows is ". It may be a "second connection portion". The "direction in which the current flows" means the direction in which the normal current flows, and does not include the above-mentioned unintended diversion direction. When the current flowing through the heater is alternating current, the direction of current flow changes periodically. In that case, the "direction in which the current flows" means the direction (one direction) of the current specified at an arbitrary timing. That is, the first connection portion G1 and the second connection portion G2 referred to here are one side in the direction of the current specified at an arbitrary timing regardless of whether the current flowing through the heater is direct current or alternating current. It is an expression for conveniently distinguishing the connection part of the above and the connection part on the other side. Therefore, in the present invention, the direction of the electric current is not limited to one direction.

Further, in FIGS. 10 and 13, each resistance heating element 59 (590) is designated as a first area A1 and a second area A2 with reference to the center line M of the base material longitudinal direction U of each resistance heating element 59 (590). It is divided into. In that case, in the comparative example and the embodiment of the present invention, the area to which the first connecting portion G1 and the second connecting portion G2 are connected differs in some of the resistance heating elements 59 (590) as follows. ing.

Specifically, in the comparative example shown in FIG. 10, the first connection portion G1 is arranged in the first area A1 (left side) of all the resistance heating elements 590. Further, the second connection portion G2 is arranged in the second area A2 (right side) of all the resistance heating elements 590.

On the other hand, in the embodiment of the present invention shown in FIG. 13, the area to which the first connection portion G1 and the second connection portion G2 are connected is a part of the resistance heating element 59 and the other resistance heating elements. It is different from the body 59. Specifically, the areas to which the first connecting portions G1 and the second are connected are different between the fourth and fifth resistance heating elements 59 from the left in the figure and the other resistance heating elements 59. (Left and right are reversed).

As described above, in the embodiment of the present invention, the area to which the first connecting portion G1 and the second connecting portion G2 are connected is made different between a part of the resistance heating element 59 and the other resistance heating element 59. As a result, the heat generation distribution of the feeder line in each block can be adjusted.

14 and 15 show the calorific value of the feeder line according to the embodiment of the present invention. FIG. 14 shows the amount of heat generated by the feeder line for each block when all the resistance heating elements 59 generate heat. On the other hand, FIG. 15 shows the amount of heat generated by the feeder line for each block when only the first heat generating portion 60A generates heat and an unintended diversion occurs. The conditions for the current flowing through each feeder and the method for calculating the calorific value are the same as in the above example.

Further, FIGS. 16 and 17 show graphs comparing the heat generation distribution in the embodiment of the present invention with the heat generation distribution in the comparative example. FIG. 16 shows the heat generation distribution when all the resistance heating elements generate heat. On the other hand, FIG. 17 shows the heat generation distribution when only the first heat generating portion generates heat and an unintended diversion occurs. The dotted line in each figure is the heat generation distribution of the feeder line in the comparative example, and the solid line is the heat generation distribution of the feeder line in the embodiment of the present invention. Further, in FIGS. 16 and 17, the total calorific value of the feeder line in the first block of the comparative example is set to “1”, and the total calorific value of the other blocks is shown based on this total calorific value.

As shown in FIGS. 16 and 17, in each case, in the embodiment of the present invention, the calorific value in the 4th block and the 5th block on the central side is significantly increased as compared with the comparative example. .. As a result, in the embodiment of the present invention, the difference between the block having the highest total calorific value and the block having the lowest total calorific value is smaller than that of the comparative example, and the temperature variation is suppressed.

As described above, in the embodiment of the present invention, if the area to which the first connecting portion G1 and the second connecting portion G2 are connected is different between the partial resistance heating element 59 and the other resistance heating element 59. By doing so, it is possible to suppress variations in the heat generation distribution in the feeder line. As a result, variations in temperature over the longitudinal direction of the heater 22 or the fixing belt 20 can be suppressed, image defects such as uneven gloss are less likely to occur, and image quality can be maintained.

Next, an embodiment different from the above-described embodiment (first embodiment of the present invention) will be described. In the following description, a part different from the above-described embodiment will be mainly described, and the other parts will be the same as the above-described embodiment, and thus the description thereof will be omitted.

FIG. 18 is a plan view of the heater 22 according to the second embodiment of the present invention.

In the case of the first embodiment shown in FIG. 13 described above, in any of the resistance heating elements 59, the first connection portion G1 and the second connection portion G2 are arranged in different areas of each resistance heating element 59. ing. On the other hand, in the case of the second embodiment shown in FIG. 18, in some of the resistance heating elements 59, the first connection portion G1 and the second connection portion G2 are arranged in the same area. Specifically, in the case of the example shown in FIG. 18, in each of the first and sixth resistance heating elements 59 from the left in the figure, the first connection portion G1 and the second connection portion G2 are both resistance heating elements 59. It is located in the second area A2 (right side) of. Further, in the second resistance heating element 59 from the left shown in FIG. 18, both the first connection portion G1 and the second connection portion G2 are arranged in the first area A1 (left side) of the resistance heating element 59. ing. In each of the other resistance heating elements 59, the first connection portion G1 and the second connection portion G2 are arranged in different areas (opposite sides to each other) of each resistance heating element 59.

19 and 20 show the heat generation distribution of each feeder in the second embodiment. The calorific value shown in FIG. 19 is the calorific value of the feeder line for each block when all the resistance heating elements 59 generate heat. On the other hand, the calorific value shown in FIG. 20 is the calorific value of the feeder line for each block when only the first heat generating portion 60A generates heat and an unintended diversion occurs. The conditions for the current flowing through each feeder and the method for calculating the calorific value are the same as in the above example.

Then, FIGS. 21 and 22 show the heat generation distribution of the feeder line comparing the second embodiment of the present invention in addition to the comparative example and the first embodiment of the present invention. The heat generation distribution shown in FIG. 21 is a heat generation distribution when all resistance heating elements generate heat. On the other hand, the heat generation distribution shown in FIG. 22 is a heat generation distribution when only the first heat generating portion generates heat and an unintended diversion occurs. The dotted line in each figure is the heat generation distribution of the feeder line in the comparative example, the solid line is the heat generation distribution of the feeder line in the first embodiment of the present invention, and the alternate long and short dash line is the heat generation of the feeder line in the second embodiment of the present invention. It is a distribution.

As can be seen from FIGS. 21 and 22, in the second embodiment of the present invention indicated by the alternate long and short dash line, the calorific value in the third block is significantly larger than that in the first embodiment of the present invention indicated by the solid line. It is rising. As described above, in the second embodiment of the present invention, the variation in the temperature distribution of the feeder line can be further suppressed, and the image quality can be improved.

Subsequently, FIG. 23 shows the configuration of the heater 22 according to the third embodiment of the present invention.

In the third embodiment shown in FIG. 23, the first feeder line 62A and the second feeder line 62B are a part of the resistance heating elements 59 (the second and third resistance heating elements 59 from the left in the figure). It is connected to the above via an inclined portion 620. The inclined portion 620 is a part of the first feeder line 62A or the second feeder line 62B, and is arranged so as to be inclined with respect to the longitudinal direction U of the base material. In this way, the feeder lines 62A and 62B and the resistance heating elements 59 may be connected via the inclined portion 620. In the other resistance heating element 59, the feeder lines 62A to 62C and each resistance heating element 59 are connected via a portion parallel to the lateral direction Y of the base material and a portion parallel to the longitudinal direction U of the base material. ing.

24 and 25 show the heat generation distribution of each feeder in the third embodiment. The heat generation distribution shown in FIG. 24 is the heat generation distribution of the feeder line when all the resistance heating elements 59 generate heat. On the other hand, the heat generation distribution shown in FIG. 25 is the heat generation distribution of the feeder line when only the first heat generating portion 60A generates heat and an unintended diversion occurs. The calorific value generated in each inclined portion 620 is also taken into consideration in the total calorific value in the third embodiment. That is, since the inclined portion 620 is arranged over a certain range in the longitudinal direction U of the base material, the inclined portion 620 is treated as a portion that affects the heat generation distribution in the longitudinal direction U of the base material. The conditions of the current flowing through each feeder and the calculation method of the calorific value are the same as those in the above example.

Further, FIGS. 26 and 27 show graphs comparing the heat generation distribution in the comparative example and the heat generation distribution in the third embodiment of the present invention. The heat generation distribution shown in FIG. 26 is a heat generation distribution when all resistance heating elements generate heat. On the other hand, the heat generation distribution shown in FIG. 27 is a heat generation distribution when only the first heat generating portion generates heat and an unintended diversion occurs. In each figure, the dotted line is the heat generation distribution of the feeder line in the comparative example, and the solid line is the heat generation distribution of the feeder line in the third embodiment of the present invention.

As shown in FIGS. 26 and 27, in each case, in the third embodiment of the present invention, the heat generation amount of the block on the central side can be increased as compared with the comparative example, and the heat generation distribution of the feeder line can be increased. Variation can be suppressed. Further, in the third embodiment of the present invention, since the inclined portion 620 is provided, the calorific value of the inclined portion 620 can be added to the calorific value of each block. This makes it possible to finely adjust the heat generation distribution.

Further, FIG. 28 shows the configuration of the heater 22 according to the fourth embodiment of the present invention.

In the case of the third embodiment shown in FIG. 23 described above, in any of the resistance heating elements 59, the first connecting portion G1 and the second connecting portion G2 are arranged in different areas from each other. On the other hand, in the case of the fourth embodiment shown in FIG. 28, in some of the resistance heating elements 59, the first connection portion G1 and the second connection portion G2 are arranged in the same area. Specifically, in the case of the example shown in FIG. 28, in each of the first and second resistance heating elements 59 from the left in the figure, the first connection portion G1 and the second connection portion G2 are both resistance heating elements 59. It is located in the second area A2 (right side) of. Further, in the sixth resistance heating element 59 from the left shown in FIG. 28, both the first connection portion G1 and the second connection portion G2 are arranged in the first area A1 (left side) of the resistance heating element 59. There is.

Further, in the fourth embodiment, the first feeder line 62A and the second feeder line 62B are respectively for the second, third, fourth, and sixth resistance heating elements 59 from the left in the figure. It is connected via an inclined portion 620. Above all, in each of the second and sixth resistance heating elements 59 from the left in the figure, the first connection portion G1 and the second connection portion G2 of the inclined portion 620 are arranged in the same area of the resistance heating element 59. .. In this way, the connection positions of the inclined portion 620 with respect to the resistance heating element 59 (the first connection portion G1 and the second connection portion G2) may be the same area of the resistance heating element 59.

29 and 30 show the heat generation distribution of each feeder in the fourth embodiment. The heat generation distribution shown in FIG. 29 is the heat generation distribution of the feeder line when all the resistance heating elements 59 generate heat. On the other hand, the heat generation distribution shown in FIG. 30 is the heat generation distribution of the feeder line when only the first heat generating portion 60A generates heat and an unintended diversion occurs. Similar to the third embodiment described above, in the fourth embodiment as well, the calorific value generated at each inclined portion 620 is added to the total calorific value. The conditions for the current flowing through each feeder and the method for calculating the calorific value are the same as in the above example.

Further, FIGS. 31 and 32 show the heat generation distribution of the feeder line comparing the fourth embodiment of the present invention in addition to the comparative example and the third embodiment of the present invention. The temperature distribution shown in FIG. 31 is a heat generation distribution when all resistance heating elements generate heat. On the other hand, the temperature distribution shown in FIG. 32 is a heat generation distribution when only the first heat generating portion generates heat and an unintended diversion occurs. In each figure, the dotted line is the heat generation distribution of the feeder line in the comparative example, the solid line is the heat generation distribution of the feeder line in the third embodiment of the present invention, and the alternate long and short dash line is the heat generation of the feeder line in the fourth embodiment of the present invention. It is a distribution.

As can be seen from FIGS. 31 and 32, in the fourth embodiment shown by the alternate long and short dash line, the variation in the temperature distribution of the feeder line is further suppressed as compared with the third embodiment shown by the solid line. That is, according to the fourth embodiment, the difference between the block having the highest total calorific value and the block having the lowest total calorific value can be further reduced.

In each of the above-described embodiments, the present invention is applied to a heater having three electrode portions and capable of independently controlling heat generation of a part of the resistance heating element and the other resistance heating element. explained. However, the present invention is not limited to such a heater, and can be applied to a heater having two electrode portions and controlling heat generation of all resistance heating elements together.

Hereinafter, an example in which the present invention is applied to a heater having two electrode portions will be described together with a comparative example.

FIG. 33 is a heater 220 according to a comparative example. Two electrode portions 610A and 610B, a plurality of resistance heating elements 590, and two feeder lines 620A and 620B connecting them are provided on the base material 500. The plurality of resistance heating elements 590 are connected in parallel to the first electrode portion 610A provided on the one end side in the longitudinal direction U of the base material via the first feeder line 620A. Further, each resistance heating element 590 is connected in parallel to the second electrode portion 610B provided on the other end side in the longitudinal direction U of the base material via the second feeder line 620B. When a voltage is applied to the first electrode portion 610A and the second electrode portion 610B, a current flows through all the resistance heating elements 590, and each resistance heating element 590 generates heat.

Here, among the connection portions of the feeder lines 620A and 620B connected to each resistance heating element 590, the connection portion G1 of the first feeder line 620A arranged on one side in the lateral direction of the base material is referred to as ". It is referred to as "the first connection part". Further, the connecting portion G2 of the second feeder line 620B arranged on the other side in the lateral direction of the base material is referred to as a "second connecting portion". Further, each resistance heating element 590 is divided into a first area and a second area with reference to the center line M in the longitudinal direction. In that case, in the comparative example, the connecting areas of the first connecting portion G1 and the second connecting portion G2 have the same embodiment in all the resistance heating elements 590. Specifically, in the example shown in FIG. 33, all the first connecting portions G1 are arranged in the second area A2, and all the second connecting portions G2 are arranged in the first area A1.

FIG. 34 shows the heat generation distribution of each feeder line in the comparative example. As shown in FIG. 34, in the comparative example, the total heat generation amount of the feeder line tends to be large in the blocks on both ends and low in the block on the center side, and the heat generation distribution of the feeder line varies.

Subsequently, FIG. 35 shows the heater 22 according to the embodiment (fifth embodiment) of the present invention.

In the embodiment of the present invention shown in FIG. 35, unlike the comparative example shown in FIG. 33, the first connection portion G1 (connection portion G1 of the first feeder line 62A) and the second connection portion G2 (second connection portion G2). The area to which each of the connection portions G2) of the feeder line 62B is connected is different between a part of the resistance heating element 59 and the other resistance heating element 59. Specifically, in the example shown in FIG. 35, the area to which each of the first connection portion G1 and the second connection portion G2 is connected is defined as the resistance heating elements 59 at both ends and the other resistance heating elements 59. The left and right are reversed in. Other than that, the configuration is the same as that of the comparative example shown in FIG. 33.

FIG. 36 shows the heat generation distribution of each feeder line according to the embodiment of the present invention. Further, FIG. 37 shows the heat generation distribution of the feeder line comparing the comparative example and the embodiment of the present invention. In FIG. 37, the dotted line is the heat generation distribution of the feeder line in the comparative example, and the solid line is the heat generation distribution of the feeder line in the embodiment of the present invention. Further, in FIG. 37, the total calorific value of the feeder line in the first block of the comparative example is set to “1”.

As shown in FIG. 37, in the embodiment of the present invention shown by the solid line, the calorific value in the blocks at both ends can be significantly reduced as compared with the comparative example shown by the dotted line, and the temperature distribution of the feeder line varies. Can be suppressed. Specifically, in the comparative example, the difference between the block having the highest total calorific value and the block having the lowest total calorific value is 3200. On the other hand, in the embodiment of the present invention, the difference is 1600. As described above, even when the present invention is applied to a heater having two electrode portions and all resistance heating elements are controlled to generate heat together, it is possible to suppress variations in heat generation distribution in the feeder line, and the heater or the fixing belt can be used. It is possible to suppress variations in temperature over the longitudinal direction.

In the case of the example shown in FIG. 35, in each of the resistance heating elements 59, the first connection portion G1 and the second connection portion G2 are arranged in different areas of each resistance heating element 59. However, the present invention is not limited to this, and similarly to the second embodiment shown in FIG. 18 described above, in some resistance heating elements 59, the first connection portion G1 and the second connection portion G2 are each resistance. It may be located in the same area of the heating element 59. Further, at least one of the first feeder line 62A and the second feeder line 62B may have an inclined portion 620 as in each embodiment shown in FIG. 23 or FIG. 28 described above.

As described above, in the heater 22 according to each embodiment of the present invention, the area where each of the first connection portion G1 and the second connection portion G2 is connected is defined as a part of the resistance heating element 59 and other parts. It is different from the resistance heating element 59 of. As a result, the total heat generation amount of the feeder lines in each block partitioned for each resistance heating element can be adjusted, and the variation in the heat generation distribution in the longitudinal direction of the heater can be suppressed.

Further, the variation in temperature distribution can be suppressed only by changing the connection position between the feeder line and the resistance heating element. As a result, a large design change can be avoided. For example, by making the material or thickness of some feeders different from the material or thickness of other feeders, it is possible to change the resistance value of the feeders and adjust the amount of heat generated by the feeders. However, the method of changing the material or thickness of the feeder has a problem in terms of influence on the processability of the heater, the manufacturing cost, or the image quality. On the other hand, in the case of the embodiment of the present invention, it is not necessary to change the resistance value by changing the material or thickness between some feed lines and other feeders, so that the resistance value of the feeder can be changed. It can be the same throughout. Therefore, it is easy to process the feeder line by screen printing or the like, the manufacturing cost is low, and the influence on the image quality due to the difference in the thickness of the feeder line can be avoided.

Further, according to the configuration according to each embodiment of the present invention, even if the current flowing through the resistance heating element is increased in order to increase the speed of the image forming apparatus, it is possible to suppress the variation in the heat generation distribution of the feeder line. Therefore, the present invention can cope with high speed of the image forming apparatus. That is, even in a situation where the amount of heat generated by the feeder line increases and the variation in the heat generation distribution becomes remarkable, the variation in the heat generation distribution can be suppressed, so that problems such as uneven gloss can be suppressed and the image quality can be maintained.

In addition, if the feeder line is made thinner in order to reduce the size of the heater in the lateral direction, the amount of heat generated may increase as the resistance value of the feeder increases, or the above-mentioned unintended diversion may occur. There is. However, by applying the configuration according to each embodiment of the present invention to the heater, it is possible to suppress variations in the heat generation distribution of the feeder line, so that it is possible to reduce the size of the heater in the lateral direction.

Therefore, the present invention can be expected to have a greater effect by being applied to a heater having a smaller dimension in the lateral direction for miniaturization. Specifically, in FIG. 38, assuming that the lateral dimension of the heater 22 (base material 50) is Q and the lateral dimension of the resistance heating element 59 is R, the ratio of R to Q (R / Q) is 25%. When the present invention is applied to the above heater 22, a great effect can be expected. Further, if the heater 22 has a dimensional ratio (R / Q) in the lateral direction of 40% or more, the effect of applying the present invention to the heater becomes even greater. The lateral dimension Q of the heater 22 means the lateral dimension of the base material 50. Further, the lateral dimension R of the resistance heating element 59 means the lateral dimension of one resistance heating element 59 as a whole. In the example shown in FIG. 38, since the base material 50 of the heater 22 is formed in a rectangular shape, the lateral dimension Q of the heater 22 is the same at any position in the longitudinal direction. However, the edge of the base material 50 may have irregularities, and the lateral dimension Q may change. In that case, the dimension in which the heater 22 is minimized in the lateral direction within the longitudinal range in which the resistance heating element 59 is arranged is defined as the lateral dimension Q of the heater 22.

In some resistance heating elements 59 and other resistance heating elements 59, the connection portions having different connection areas may be both the first connection portion G1 and the second connection portion G2, or one of them. It may be. Of the first connection portion G1 and the second connection portion G2, at least one connection area is divided for each resistance heating element by being different between some resistance heating elements 59 and other resistance heating elements 59. The total amount of heat generated by the feeder lines in each block can be adjusted. As a result, it is possible to suppress variations in the heat generation distribution over the longitudinal direction of the heater.

Further, which resistance heating element 59 should be used as the resistance heating element 59 having different connection areas of the first connection portion G1 or the second connection portion G2 should be appropriately determined according to the layout of the heater, the heat generation distribution, and the like. Just do it.

In the comparative examples shown in FIGS. 16 and 17 described above, the calorific value of the feeder tends to be high in the blocks at both ends and low in the blocks on the center side. In this case, it is desirable to design the connection structure of the feeder so that the amount of heat generated by the feeders in the blocks at both ends is small and the amount of heat generated by the feeders in the central block is large. For that purpose, in at least one of the resistance heating elements 59 arranged at other than both ends (center side), at least one connection area of the first connection portion G1 and the second connection portion G2 is arranged at both ends. It should be different from the connection area of the resistance heating element 59. If the connection areas of the first connection portion G1 and the second connection portion G2 of the central resistance heating element 59 are the same as the connection areas of the resistance heating elements 59 at both ends, the block having a small heat generation amount is used. There is a risk that the amount of heat generated will become smaller. Therefore, as shown in the example shown in FIG. 13, the first connection portion G1 is formed between the resistance heating element 59 at both ends (first and seventh from the left) and the resistance heating element 59 at the center (fourth from the left). It is desirable that at least one connection area of the second connection portion G2 is different from that of the second connection portion G2.

Further, if the connection areas of the first connection portion G1 and the second connection portion G2 are alternately arranged so as to be different between the resistance heating elements 59 arranged adjacent to each other, the block in which the amount of heat generation is desired to be increased. On the contrary, the amount of heat generated may be small. Therefore, as in the example shown in FIG. 13, among the resistance heating elements 59 arranged adjacent to each other, at least one set of resistance heating elements 59 (for example, the first and second resistance heating elements 59 from the left). It is desirable that the connection areas of the first connection portion G1 and the second connection portion G2 are the same.

Further, as in each example shown in FIG. 13 or FIG. 35, when the connection areas of the first connection portion G1 and the second connection portion G2 are different areas from each other in any of the resistance heating elements 59. , Deterioration of each resistance heating element 59 also occurs in the same manner. In this case, uneven heat generation over time is unlikely to occur, and it is easy to predict defects due to deterioration. Further, as in the example shown in FIG. 39, there is also a case where each connection area of the first connection portion G1 and the second connection portion G2 is the same area in all the resistance heating elements 59 (first connection portion). Both G1 and the second connection G2 are located in the first zone A1 or the second zone A2), which has the same advantages as the example shown in FIG. 13 or 35 above.

Further, the position where the feeding line 62 is connected to the resistance heating element 59 (connection portions G1 and G2) is preferably a position on the end side of the resistance heating element 59 on the center line M. When the feeding line 62 is connected to the end side of the resistance heating element 59, the temperature unevenness that may occur in the resistance heating element 59 is different from the case where the feeding line 62 is connected on the center line M of the resistance heating element 59. Can be avoided.

The shape of the resistance heating element 59 may be a block shape as shown in FIG. 13 or a shape having a folded portion J reciprocating in the longitudinal direction U of the base material as shown in FIG. 35.

Further, in each of the above-described embodiments, the portion K (see, for example, FIG. 38) extending in the lateral direction Y of the base material, which connects the feeder lines 62A to 62C and the resistance heating element 59, is the feeder lines 62A to 62A. It is a part of 62C. However, the present invention is not limited to this, and as in the example shown in FIG. 40, such a portion K extending in the lateral direction Y of the base material may be a part of the resistance heating element 59.

Further, the connection portions G1 and G2 between the resistance heating elements 59 and the feeder lines 62A to 62C are not limited to the case where they are arranged at the corners of the block-shaped resistance heating elements 59 (see, for example, FIG. 13). As shown in the example shown in FIG. 41, the connection portions G1 and G2 between the resistance heating elements 59 and the feeder lines 62A to 62C are edges extending in the lateral direction Y of the base material at the right end or the left end of the resistance heating element 59. It may be arranged all over.

The present invention is also applicable to the heater 22 as shown in FIGS. 42 to 44. In the heaters 22 shown in FIGS. 42 to 44, a plurality of resistance heating elements 59 adjacent to each other are continuous with each other via any of the feeder lines 62A to 62C, except for a part of the resistance heating elements 59. Have been placed. On the other hand, some of the resistance heating elements 59 are arranged apart from each other so that the insulating region F is interposed between them. In FIGS. 42 to 44, an insulating region F is interposed between the resistance heating elements 59 arranged on both ends in the longitudinal direction U of the base material and the resistance heating elements 59 arranged between them. .. The resistance heating elements 59 (resistance heating elements group) separated via the insulating region F are connected to the same electrode portion (second electrode portion 61B) via the same feeder line (second feeder line 62B). At the same time, they are connected to different electrode portions (first electrode portion 61A or third electrode portion 61C) via separate feeders (first feeder line 62A or third feeder line 62C). Therefore, the resistance heating elements 59 (resistive heating element group) separated via the insulating region F can generate heat independently of each other. Here, the third electrode portion 61C and the third feeder line 62C connected to the third electrode portion 61C are for the resistance heating element 59 on one end side and the resistance heating element 59 on the other end side in the longitudinal direction U of the base material, respectively. It is divided into and separately provided. However, the present invention is not limited to this, and each third electrode portion 61C and each third feeding line 62C may be integrated into one electrode portion and one feeding line.

In each of the examples shown in FIGS. 42 to 44, when a voltage is applied to the first electrode portion 61A and the second electrode portion 61B to cause a potential difference between the two electrode portions 61A and 61B, each resistor on the center side is generated. Only the heating element 59 generates heat. Further, when a voltage is applied to the third electrode portion 61C and the second electrode portion 61B to cause a potential difference between the two electrode portions 61C and 61B, only each resistance heating element 59 on both ends generates heat. Further, when a voltage is applied to all the electrode portions 61A to 61C, all the resistance heating elements 59 generate heat.

Even in such a heater 22, the amount of heat generated by each resistance heating element 59 can be adjusted by changing the connection positions of the feeder lines 62A to 62C with respect to the resistance heating element 59, as in the above-described embodiment. That is, in FIGS. 42 to 44, the connecting portion G1 between the first feeding line 62A and the third feeding line 62C on one side of the lateral direction Y of the base material and the resistance heating element 59 is the “first connecting portion”. ". Further, the connecting portion G2 between the second feeder line 62B on the other side in the lateral direction Y of the base material and the resistance heating element 59 is the "second connecting portion". Here, if each resistance heating element 59 is divided into a first area A1 and a second area A2 with reference to the center line M of the base material longitudinal direction U of each resistance heating element 59, the first connection portion G1 and The connection area of the second connection portion G2 may be different between a part of the resistance heating element 59 and the other resistance heating element 59.

Specifically, in the first resistance heating element 59 from the left in FIG. 42, the first connecting portion G1 is arranged in the second area A2, and the second connecting portion G2 is arranged in the first area A1. Has been done. On the other hand, in the second resistance heating element 59 from the left, on the contrary, the first connecting portion G1 is arranged in the first area A1 and the second connecting portion G2 is arranged in the second area A2. ing. As described above, resistance heating is generated because at least one connection area of the first connection portion G1 and the second connection portion G2 is different between the part of the resistance heating element 59 and the other resistance heating element 59. You can adjust the amount of heat generated for each body. As a result, it is possible to suppress variations in the heat generation distribution over the longitudinal direction of the heater.

Further, a temperature detecting means (temperature sensor) such as a thermistor for temperature control or a thermostat used as a safety device for preventing excessive temperature rise may be arranged at a position corresponding to any of the resistance heating elements. In that case, as shown in FIG. 45, it is desirable that the temperature detecting means 34 is arranged on the side where the temperature is higher than the center line M of the resistance heating element 59 in the longitudinal direction U of the base material (on the right side in FIG. 45). .. By arranging the temperature detecting means 34 at such a position, the temperature detecting means 34 can easily detect an excessive temperature rise in advance, and the safety is improved. Further, it is possible to suppress the occurrence of so-called high temperature offset in which the molten toner on the paper adheres to the fixing belt due to the high temperature.

Further, in the embodiment of the present invention, a resistance heating element having PTC characteristics may be used in order to further suppress the variation in temperature over the longitudinal direction of the heater. The PTC characteristic is a characteristic in which the resistance value increases as the temperature increases (the heater output decreases when a constant voltage is applied). Since the heat generating portion has PTC characteristics, when the heater is low temperature, the heater rises at high speed due to high output, and when the heater is high temperature, excessive temperature rise of the heater can be suppressed by low output. For example, if the TCR coefficient of the PTC characteristic is about 300 to 4000 ppm / degree, the cost can be reduced while securing the resistance value required for the heater. More preferably, the TCR coefficient is 500 to 2000 ppm / degree.

The temperature coefficient of resistance (TCR) can be calculated using the following equation (2). In the formula (2), T0 is a reference temperature, T1 is an arbitrary temperature, R0 is a resistance value at a reference temperature T0, and R1 is a resistance value at an arbitrary temperature T1. For example, in the above-mentioned heater 22 shown in FIG. 13, when the resistance value between the first electrode portion 61A and the second electrode portion 61B is 25 ° C. (reference temperature T0), the resistance value is 10Ω (resistance value R0). If it is 12Ω (resistance value R1) at 125 ° C. (arbitrary temperature T1), the resistance temperature coefficient is 2000 ppm / ° C. from the equation (2).

Further, the present invention can be applied to the fixing device as shown in FIGS. 46 to 48 in addition to the fixing device described above. Hereinafter, the configurations of the fixing devices shown in FIGS. 46 to 48 will be briefly described.

First, in the fixing device 9 shown in FIG. 46, the pressing roller 90 is arranged on the side opposite to the pressing roller 21 side with respect to the fixing belt 20. The fixing belt 20 is sandwiched between the pressing roller 90 and the heater 22 for heating. On the other hand, on the pressure roller 21 side, the nip forming member 91 is arranged on the inner circumference of the fixing belt 20. The nip forming member 91 is supported by the stay 24. The nip forming member 91 and the pressure roller 21 sandwich the fixing belt 20 to form the nip portion N.

Next, in the fixing device 9 shown in FIG. 47, the above-mentioned pressing roller 90 is omitted. Further, in the fixing device 9, the heater 22 is formed in an arc shape according to the curvature of the fixing belt 20 in order to secure the circumferential contact length between the fixing belt 20 and the heater 22. Other configurations are the same as those of the fixing device 9 shown in FIG.

Finally, in the fixing device 9 shown in FIG. 48, a pressure belt 92 is provided in addition to the fixing belt 20. Further, in the fixing device 9, the heating nip (first nip portion) N1 and the fixing nip (second nip portion) N2 are separated. That is, the nip forming member 91 and the stay 93 are arranged on the side opposite to the fixing belt 20 side with respect to the pressure roller 21. Further, the pressure belt 92 is rotatably arranged so as to include the nip forming member 91 and the stay 93. When the paper P passes through the fixing nip N2 between the pressure belt 92 and the pressure roller 21, the paper P is heated and pressurized to fix the image. Other configurations are the same as those of the fixing device 9 shown in FIG.

Further, the present invention can be applied not only to an electrophotographic image forming apparatus provided with a fixing device as described above, but also to an inkjet image forming apparatus provided with a drying device for drying ink applied to paper. Further, the present invention can also be applied to a thermocompression bonding device provided with a thermocompression bonding portion for thermocompression bonding the overlapped adhesive surfaces. Examples of the thermocompression bonding device include a laminator that thermocompression-bonds a film as a covering member to the surface of a sheet such as paper, and a heat sealer that thermocompression-bonds a seal portion of a packaging material. By applying the present invention to such an inkjet image forming apparatus or a thermocompression bonding apparatus, it is possible to suppress variations in the temperature distribution of the heater in these apparatus as well.

1Y, 1M, 1C, 1Bk image formation unit (image forming unit)
9 Fixing device 19 Heating device 20 Fixing belt (fixing member, belt member)
21 Pressurizing roller (opposing member)
22 Heater (heating member)
50 Base material 59 Resistance heating element (heating element)
60 Heat-generating part 60A First heat-generating part 60B Second heat-generating part 61 Electrode part 61A First electrode part 61B Second electrode part 61C Third electrode part 62 Feed line (conductor)
62A 1st feeder 62B 2nd feeder 62C 3rd feeder 620 Inclined part A1 1st area A2 2nd area F Insulation area G1 1st connection part G2 2nd connection part J Folded part M Center line U Longitudinal direction of base material Y Short side direction of base material

Japanese Unexamined Patent Publication No. 2016-62024

Claims (14)

A plate-shaped base material with a longitudinal direction and
A plurality of electrode portions provided on the base material and
A plurality of heating elements arranged along the longitudinal direction of the base material, and
A plurality of conductors provided on the base material and connecting the electrode portion and the heating element,
It is a heating member provided with
The heating elements adjacent to each other are arranged between them with an insulating region.
Of the plurality of connecting portions connecting the conductor and the heating element, the connecting portion connecting the conductor and the heating element arranged on one side of the heating element in the lateral direction of the base material is used. The first connecting portion is used, and the connecting portion connecting the conductor and the heating element arranged on the other side of the heating element in the lateral direction of the base material is used as the second connecting portion.
When each heating element is divided into a first area and a second area with reference to the center line in the longitudinal direction of each heating element,
A heating member characterized in that the area to which at least one of the first connecting portion and the second connecting portion is connected is different between a part of the heating element and the other heating element. As the plurality of electrode portions, a first electrode portion and a second electrode portion are provided.
As the plurality of conductors, a first conductor connecting the first electrode portion and the heating element and a second conductor connecting the second electrode portion and the heating element are provided.
Assuming that the connection portion of the first conductor to the heating element is the first connection portion and the connection portion of the second conductor to the heating element is the second connection portion.
The heating member according to claim 1, wherein the area to which at least one of the first connecting portion and the second connecting portion is connected differs between a part of the heating element and the other heating element. As the plurality of electrode portions, a first electrode portion, a second electrode portion, and a third electrode portion are provided.
As the plurality of conductors, a first conductor connecting the first electrode portion and the heating element, a second conductor connecting the second electrode portion and the heating element, and the third conductor. A third conductor for connecting the electrode portion and the heating element is provided.
Assuming that the connection portion of the first conductor or the third conductor to the heating element is the first connection portion and the connection portion of the second conductor to the heating element is the second connection portion.
The heating member according to claim 1, wherein the area to which at least one of the first connecting portion and the second connecting portion is connected differs between a part of the heating element and the other heating element. At least one of the heating elements arranged at other than both ends is the area where at least one of the first connection portion and the second connection portion is connected to the heating element arranged at both ends. The heating member according to any one of claims 1 to 3, wherein the heating member is different. From claim 1, among the heating elements arranged adjacent to each other, at least one set of the heating elements has the same area to which the first connecting portion and the second connecting portion are connected. The heating member according to any one of 4. The conductor has an inclined portion that is inclined with respect to the longitudinal direction of the base material.
The heating member according to any one of claims 1 to 5, wherein the conductor is connected to the heating element via the inclined portion. The heating member according to any one of claims 1 to 6, wherein the first connection portion and the second connection portion in at least one heating element are arranged in the same area. The heating member according to any one of claims 1 to 7, wherein the first connecting portion and the second connecting portion are arranged at one end or the other end of the heating element in the longitudinal direction of the base material. The heating member according to any one of claims 1 to 8, wherein the first connecting portion and the second connecting portion are arranged in a corner of the heating element. The heating member according to any one of claims 2 to 9, wherein the heating element has a folded portion that reciprocates in the longitudinal direction. A plate-shaped base material with a longitudinal direction and
On the substrate
The first electrode part, the second electrode part, the third electrode part,
A plurality of heating elements arranged along the longitudinal direction of the base material, and
A first conductor connecting the first electrode portion and the heating element,
A second conductor connecting the second electrode portion and the heating element,
A third conductor connecting the third electrode portion and the heating element,
An insulating region arranged between at least a part of the heating elements and the adjacent heating element, among the plurality of heating elements.
It is a heating member provided with
The connection portion of the first conductor or the third conductor to the heating element is defined as the first connection portion.
The connection portion of the second conductor to the heating element is used as the second connection portion.
When each heating element is divided into a first area and a second area with reference to the center line in the longitudinal direction of each heating element,
A heating member characterized in that the area to which at least one of the first connecting portion and the second connecting portion is connected is different between a part of the heating element and the other heating element. A heating device having the heating member according to any one of claims 1 to 11. A heating device having the heating member according to any one of claims 2 or 3, claims 4 to 10 and claim 11 according to claim 2 or 3.
A heating device having a potential difference between the second electrode portion and an electrode portion other than the second electrode portion. The heating member according to any one of claims 1 to 11.
The image forming part that forms the image and
An image forming apparatus comprising.

Images