JP7732281B2 - Fixing device, image forming apparatus, and heater manufacturing method - Google Patents

Description

This disclosure relates to a fixing device, an image forming apparatus, and a heater manufacturing method.

Known image forming devices, such as electrophotographic printers, include a fixing device that heats the sheet on which the image is formed to fix the developer image. Such fixing devices include a substrate, a heater having a resistance heating element disposed on the substrate, and a holder that holds the heater (see, for example, Patent Document 1 listed below).

Japanese Patent Application Laid-Open No. 2020-52348

In the fixing device described above, the heater and holder are positioned by forming a positioning hole in the substrate and providing a positioning protrusion on the holder that fits into this positioning hole.

However, in conventional fixing devices such as those described above, the positioning hole was configured as a recess formed so as to be recessed in the width direction of the heater. Therefore, when manufacturing this conventional fixing device by cutting out a substrate from a metal plate or the like, it was necessary to cut out the recessed portion in addition to the rectangular shape that would form the outer shape of the substrate. As a result, this conventional fixing device was unable to prevent the increase in waste material during substrate manufacturing, resulting in lower manufacturing yields and higher manufacturing costs.

The purpose of this disclosure is to provide a cost-effective fixing device, image forming apparatus, and heater manufacturing method that can improve the manufacturing yield of substrates made of metal materials.

To solve the above problems, a fixing device according to a first aspect of the present disclosure includes a substrate made of a metal material, a heater having a resistance heating element disposed on the substrate, and a holder for holding the heater; the substrate is disposed at one end in a width direction perpendicular to the longitudinal direction and has a substrate protrusion that protrudes in the width direction, and a substrate recess that is disposed at the other end in the width direction and has substantially the same shape as the substrate protrusion and is recessed in the width direction; and the holder has an engaging portion that engages with the substrate protrusion or the substrate recess.

With the above configuration, substrate protrusions and substrate recesses that are recessed in approximately the same shape as the substrate protrusions are arranged on one and the other widthwise ends of the substrate. This makes it possible to prevent an increase in waste material during substrate manufacturing and to construct an inexpensive fixing device that can improve the manufacturing yield of substrates made of metal materials.

A second aspect of the present disclosure is the fixing device of the first aspect, wherein the substrate protrusion and the substrate recess may be arranged at approximately the same position in the longitudinal direction of the substrate.

The above configuration reliably reduces the increase in waste material during substrate manufacturing, and reliably improves the manufacturing yield of substrates made from metal materials.

A third aspect of the present disclosure is a fixing device according to the first or second aspect, wherein the heater has a power supply terminal located at one end of the substrate in the longitudinal direction and a heating pattern that generates heat when power is supplied from the power supply terminal, and the substrate convex portion and the substrate concave portion may be located between the power supply terminal and the heating pattern in the longitudinal direction on the substrate.

The above configuration makes it possible to position the board relative to the holder at a position close to the power supply terminal, and prevents the power supply terminal from shifting position even if the board experiences thermal expansion in the longitudinal direction due to heat generation.

A fourth aspect of the present disclosure is the fixing device of the third aspect, wherein the heater has a power supply pattern that electrically connects the power supply terminal and the heat generating pattern, the power supply pattern has a dimension in the width direction that is smaller than the dimension in the width direction of the heat generating pattern, and the substrate recess is disposed within an area in the longitudinal direction in which the power supply pattern is formed.

The above configuration allows the width of the substrate to be reduced.

A fifth aspect of the present disclosure is the fixing device of any one of the first to fourth aspects, wherein the engagement portion may be a holder recess that can fit into the substrate protrusion.

With the above configuration, the substrate protrusion fits into the holder recess, allowing the heater to be positioned longitudinally relative to the holder.

A sixth aspect of the present disclosure is the fixing device of any one of the first to fourth aspects, wherein the engagement portion may be a holder protrusion that can fit into the board recess.

With the above configuration, the recessed portion of the substrate fits into the protruding portion of the holder, allowing the heater to be positioned longitudinally relative to the holder.

The image forming apparatus of the seventh aspect of the present disclosure includes a fixing device according to any one of the first to sixth aspects.

The above configuration makes it possible to create a low-cost image forming device that can improve the manufacturing yield of substrates made of metal materials.

An eighth aspect of the present disclosure is a method for manufacturing a heater having a substrate made of a metal material and a resistance heating element disposed on the substrate, the method comprising a manufacturing process for manufacturing a plurality of the substrates from a single metal plate, the manufacturing process including manufacturing the substrates having a substrate protrusion disposed on one end side in a width direction perpendicular to the longitudinal direction of the substrate and protruding in the width direction, and a substrate recess disposed on the other end side in the width direction and recessed in the width direction and having substantially the same shape as the substrate protrusion, wherein the manufacturing process forms the substrate recess on a substrate adjacent to the one substrate by forming the substrate protrusion on the one substrate.

With the above configuration, by forming a substrate convex portion on one substrate, a substrate concave portion can be formed on another substrate adjacent to the one substrate, thereby preventing an increase in waste material from the metal plate during substrate manufacturing. As a result, it is possible to construct a low-cost heater that can improve the manufacturing yield of substrates made from metal materials, and ultimately a low-cost fixing device and low-cost image forming apparatus that use the heater.

One aspect of the present disclosure provides a cost-effective fixing device, image forming apparatus, and heater manufacturing method that can improve the manufacturing yield of substrates made of metal materials.

1 is a diagram illustrating a schematic configuration of an image forming apparatus according to a first embodiment of the present disclosure. FIG. 2 is a cross-sectional view showing a main configuration of the fixing device shown in FIG. 1 . 1A is an exploded perspective view illustrating a specific configuration of a heater included in the heating unit, and FIG. 1B is a cross-sectional view showing a cross section of the heater. FIG. 2 is an enlarged plan view showing the main configuration of the heater. 5A and 5B are diagrams illustrating the relationship between the heater and a holder included in the heating unit. FIG. 3 is an enlarged plan view showing an example of the configuration of the main parts of the heater and the holder. FIG. 4 is a perspective view showing a specific configuration of a connector attached to the heating unit. 3A to 3C are diagrams illustrating a method for manufacturing the substrate of the heater.

[Embodiment 1]
A first embodiment of the present disclosure will be described below with reference to Figures 1 to 8. In this embodiment, a laser printer that forms an image on a sheet S1 using toner will be described as an example of an image forming apparatus 1.

[Configuration of image forming apparatus 1]
1 is a diagram illustrating a schematic configuration of an image forming apparatus 1 according to a first embodiment of the present disclosure. In the following description, a monochrome printer that performs image formation processing for monochrome images is exemplified as the image forming apparatus 1, but the present embodiment is not limited to this, and the image forming apparatus 1 may also be, for example, a color printer that performs image formation processing for full-color images.

As shown in FIG. 1, the image forming device 1 includes a housing 2, a paper feed unit 3, an image forming unit 4, a discharge roller 5, a discharge tray 6, and a main motor M. As shown in FIG. 1, the housing 2 forms the outer container of the image forming device 1 and houses the main components of the image forming device 1.

As shown in FIG. 1, the paper feed unit 3 supplies sheets S1. The paper feed unit 3 includes a paper feed tray 31, a feed roller 32, a pressure plate 33, a transport roller 34, and a registration roller 35. The paper feed tray 31 is a box-shaped member with an open top, and stores a predetermined amount of sheets S1. The sheets S1 are recording media on which an image is formed, and may be paper, plastic, or the like.

The feed roller 32 feeds out the sheet S1 stored in the paper feed tray 31. That is, when the sheet S1 is fed out, the sheet S1 on the paper feed tray 31 is brought to the feed roller 32 by the pressure plate 33, and is fed to the transport roller 34 as the feed roller 32 rotates. The transport roller 34 transports the sheet S1 toward the registration roller 35. The registration roller 35 aligns the leading edge of the sheet S1, and then transports the sheet S1 toward the image forming unit 4.

The image forming unit 4 forms an image by performing an image forming process on the sheet S1 delivered by the paper feed unit 3. As shown in FIG. 1, the image forming unit 4 includes an exposure unit 41, a transfer unit 42, a charger 43, a developing unit 44, a fixing device 45 of the present disclosure, and a photosensitive drum 46. The exposure unit 41 includes a laser light source (not shown), a polygon mirror 41G, a scanning lens 41L, a polygon motor 41M, and a reflecting mirror 41R.

The polygon mirror 41G is a rotating polygonal mirror with six reflective surfaces on the side surfaces of a regular hexagonal prism. The polygon mirror 41G deflects the light beam L1 emitted by the laser light source in a direction toward the photosensitive drum 46. The polygon motor 41M is driven by a motor driver (not shown) to rotate the polygon mirror 41G.

The exposure unit 41 deflects the light beam L1 using a polygon mirror 41G, and emits the light beam L1 from the polygon mirror 41G onto the surface of the photosensitive drum 46 via a scanning lens 41L and a reflecting mirror 41R. The exposure unit 41 scans the surface of the photosensitive drum 46 with the light beam L1, exposing the photosensitive drum 46 to light. As a result, an electrostatic latent image that constitutes the toner image described below is formed on the photosensitive drum 46. The polygon motor 41M is, for example, a brushless DC motor.

The transfer unit 42 includes a transfer roller that sandwiches the sheet S1 between itself and the photosensitive drum 46, and transfers the toner image from the photosensitive drum 46 to the sheet S1. The charger 43 includes, for example, a scorotron charger having a charging wire and grid section (not shown). In this charger 43, a charging voltage is applied to the charging wire by a high-voltage generation circuit (not shown), and a grid voltage is applied to the grid section, generating a corona discharge and uniformly charging the surface of the photosensitive drum 46. The development unit 44 includes a development roller 44R and a toner cartridge 44A containing a developer, such as toner.

In addition to the above description, for example, the transfer device 42 may include a transfer belt instead of the transfer roller. Also, for example, the charger 43 may include a charging roller instead of a scorotron-type charger.

In the image forming unit 4, the surface of the photosensitive drum 46 is uniformly charged by the charger 43, and then a light beam L1 from the exposure unit 41 forms an electrostatic latent image based on the print data on the surface of the photosensitive drum 46. The development roller 44R then supplies toner from the inside of the toner cartridge 44A to the surface of the photosensitive drum 46 on which the electrostatic latent image has been formed. This makes the electrostatic latent image visible, and a toner image is formed on the surface of the photosensitive drum 46. Then, a sheet S1 fed from the paper feed unit 3 is transported to a transfer position between the photosensitive drum 46 and the transfer unit 42, whereby the toner image formed on the surface of the photosensitive drum 46 is transferred onto the sheet S1.

The sheet S1 onto which the toner image has been transferred is transported to the fixing device 45 by the photosensitive drum 46 and transfer device 42. The fixing device 45 fixes the toner image formed on the sheet S1. Specifically, the fixing device 45 uses heat generated by the heater 60 to thermally fix the toner image on the sheet S1 transported from the photosensitive drum 46 and transfer device 42. The sheet S1 onto which the toner image has been thermally fixed is discharged onto the discharge tray 6 by the discharge rollers 5. The specific configuration of the fixing device 45 in this embodiment 1 will be described in detail later.

The main motor M is, for example, a brushless DC motor. A transmission mechanism such as a gear that transmits its rotational force is connected to the main motor M, and the main motor M functions as a power source for each component housed inside the housing 2.

[Configuration of Fixing Device 45]
The fixing device 45 of this embodiment will be specifically described with reference to Fig. 2. Fig. 2 is a cross-sectional view showing the main configuration of the fixing device 45 shown in Fig. 1.

As shown in FIG. 2, the fixing device 45 of this embodiment includes a heating unit 51 that contacts and heats the sheet S1 on which the toner image is formed, and a pressure roller 52 that applies pressure to the sheet S1. The heating unit 51 and pressure roller 52 are pressed against each other by a pressure unit (not shown). In the fixing device 45, the pressure unit is controlled in accordance with instructions from a control unit (not shown), and the toner image is fixed to the sheet S1 with a predetermined pressure applied between the heating unit 51 and the pressure roller 52.

The heating unit 51 includes a heater 60, a holder 70, a stay 80, and a belt 90. The heater 60 is a heating element configured in a rectangular shape in a plan view. The heater 60 has a first surface 60A arranged on the pressure roller 52 side and a second surface 60B facing the first surface 60A. The second surface 60B abuts against the holder 70, thereby supporting the heater 60 on the holder 70.

The holder 70 is made of, for example, a synthetic resin material and includes a guide surface 70A that guides the belt 90 and a support portion 70B that supports the heater 60. The guide surface 70A guides the belt 90 by contacting the inner peripheral surface 90A of the belt 90. The support portion 70B includes a support surface 70B1 that abuts against and supports the second surface 60B of the heater 60. The stay 80 is a reinforcing member that supports the holder 70 and is formed by bending a plate material with greater rigidity than the holder 70, for example, a metal material such as a steel plate, into a generally U-shaped cross section.

The belt 90 is an endless belt that is heat-resistant and flexible, and includes a base material made of a metal material such as stainless steel, and an insulating layer made of a synthetic resin material such as fluororesin that covers the base material (not shown). The belt 90 houses the heater 60, holder 70, and stay 80 within it, and rotates around these heaters 60, holder 70, and stay 80. Furthermore, the inner surface 90A of the belt 90 abuts against the first surface 60A of the heater 60, allowing heat from the heater 60 to be transferred to the sheet S1 via the belt 90.

The pressure roller 52 comprises a rotating shaft 52A made of a metal material and an elastic layer 52B made of a synthetic rubber material or the like that covers the surface of the rotating shaft 52A. The pressure roller 52 sandwiches the belt 90 between itself and the heater 60, forming a nip portion NP for heating and pressurizing the sheet S1.

The pressure roller 52 is driven to rotate in rotation direction R2 by the driving force transmitted from the main motor M. That is, the pressure roller 52 rotates while sandwiching the sheet S1 transported in the transport direction H between it and the belt 90, causing the belt 90 to rotate in rotation direction R1 due to the frictional forces between the pressure roller 52, the belt 90, and the sheet S1. As a result, in the fixing device 45, the sheet S1 with the transferred toner image is transported between the heating unit 51 and the pressure roller 52, whereby the toner image is thermally fixed onto the sheet S1.

[Configuration of heater 60]
Next, the heater 60 will be described in detail with reference to Figures 3 and 4. Figure 3(A) is an exploded perspective view illustrating the specific configuration of the heater 60 included in the heating unit 51, and Figure 3(B) is a cross-sectional view showing a cross section of the heater 60. Figure 4 is an enlarged plan view showing the main configuration of the heater 60.

As shown in Figures 3(A) and 3(B), the heater 60 comprises a first insulating layer Z1 having the second surface 60B, a substrate S laminated on the first insulating layer Z1, a second insulating layer Z2 laminated on the substrate S, a resistive heating element P disposed on the second insulating layer Z2, and a third insulating layer Z3 disposed to cover the resistive heating element P. The first insulating layer Z1, the second insulating layer Z2, and the third insulating layer Z3 are made of an insulator such as a glass material. The third insulating layer Z3 also has the first surface 60A, contacts the inner circumferential surface 90A of the belt 90, and also functions as a protective layer to protect the resistive heating element P from contact with the inner circumferential surface 90A.

The resistance heating element P includes a power supply terminal T having two terminals T1 and T2, a power supply pattern PE having power supply patterns PE1 and PE2 electrically connected to terminals T1 and T2, respectively, and a heating pattern PH electrically connected to the power supply pattern PE. Connectors (described below) are electrically connected to terminals T1 and T2 of the power supply terminal T, and power is supplied to the heater 60 via the connectors.

At least the heating pattern PH of the resistance heating element P is made of a conductive material with excellent heat generation properties, such as a nickel-chromium alloy or an iron-chromium alloy, and the heating pattern PH generates heat in accordance with instructions from the control unit. In other words, the current supplied to the heating pattern PH is controlled, and further, the heat generated by the heating pattern PH is increased or decreased, controlling the heating from the heater 60 to the belt 90.

In addition, the fixing device 45 of this embodiment is provided with a temperature sensor (not shown) that detects the temperature of the heater 60, and the control unit is configured to control the heater 60 using the detection results of the temperature sensor.

In addition, the heater 60 has a substrate protrusion ST and a substrate recess SU on the substrate S for positioning the heater 60 on the holder 70, which are provided in the width direction of the heater 60, i.e., on one end side and the other end side of the width direction of the substrate S.

Specifically, as shown in FIG. 4, the substrate S has, at one end of the longitudinal direction LH of the substrate S, a substrate protrusion ST that is located on one end side of the width direction SH perpendicular to the longitudinal direction LH of the substrate S and protrudes in the width direction SH, and a substrate recess SU that is located on the other end side of the width direction SH and has approximately the same shape as the substrate protrusion ST and is recessed in the width direction SH. Note that "the substrate protrusion ST and the substrate recess SU have approximately the same shape" does not mean that the substrate protrusion ST and the substrate recess SU are limited to being exactly the same shape.

Furthermore, on the substrate S, these substrate protrusions ST and substrate recesses SU are provided at approximately the same position in the longitudinal direction LH of the substrate S. Note that "approximately the same position in the longitudinal direction LH" does not necessarily mean exactly the same position in the longitudinal direction LH, but rather means that they are essentially the same position.

Furthermore, in the heater 60, a first convex portion Z1T and a first concave portion Z1U are provided in the first insulating layer Z1 at positions overlapping the substrate convex portion ST and the substrate concave portion SU, respectively. Similarly, a second convex portion Z2T and a second concave portion Z2U are provided in the second insulating layer Z2 at positions overlapping the substrate convex portion ST and the substrate concave portion SU, respectively, and a third convex portion Z3T and a third concave portion Z3U are provided in the third insulating layer Z3 at positions overlapping the substrate convex portion ST and the substrate concave portion SU, respectively.

The first convex portion Z1T, second convex portion Z2T, and third convex portion Z3T are formed at the same position in the stacking direction relative to the substrate convex portion ST to be superimposed. Furthermore, the first convex portion Z1T, second convex portion Z2T, and third convex portion Z3T are formed in substantially the same shape as the substrate convex portion ST or in a slightly smaller shape, and are configured so that when the substrate convex portion ST is fitted into the holder concave portion described below, they can be fitted into the holder concave portion together with the substrate convex portion ST. Note that "substantially the same shape" means that they are substantially the same, and is not limited to being exactly the same shape (the same applies to the relationship between the shape of the substrate concave portion SU and the shapes of the first concave portion Z1U, second concave portion Z2U, and third concave portion Z3U described below).

The first recess Z1U, second recess Z2U, and third recess Z3U are formed at the same position in the stacking direction relative to the substrate recess SU that they are to be superimposed on. Furthermore, the first recess Z1U, second recess Z2U, and third recess Z3U are formed to have substantially the same shape as or slightly larger than the substrate recess SU, and are configured to be able to fit into the holder convex portion together with the substrate recess SU when the substrate recess SU is fitted into the holder convex portion described below.

The substrate S is made of a metal material such as stainless steel. As described above, the substrate S has a substrate protrusion ST and a substrate recess SU. Therefore, even when manufacturing multiple substrates S from a metal plate made of the above-mentioned metal material, it is possible to reduce waste material and improve the manufacturing yield of the substrates S while manufacturing multiple substrates S (details will be described later).

In the above explanation, the heater 60 has a first insulating layer Z1, a substrate S, a second insulating layer Z2, a resistive heating element P, and a third insulating layer Z3. However, the heater 60 of this embodiment is not limited in any way as long as it has a substrate S made of a metal material and a resistive heating element P disposed on the substrate S.

[Configuration of Main Parts of Fixing Device 45]
Next, the essential configuration of the fixing device 45 of this embodiment will be described in detail with reference to Figures 5 to 7. Figure 5 is a diagram illustrating the relationship between the heater 60 and the holder 70 included in the heating unit 51. Figure 6 is an enlarged plan view showing an example of the essential configuration of the heater 60 and the holder 70. Figure 7 is a perspective view showing the specific configuration of the connector 100 attached to the heating unit 51. Note that the third insulating layer Z3 of the heater 60 is omitted from Figures 5 and 6.

As shown in Figures 5 and 6, in the fixing device 45 of this embodiment, the holder 70 is provided with a holder recess 70U as an engaging portion that can fit into the substrate protrusion ST of the substrate S. The holder 70 also is provided with a holder protrusion 70T as an engaging portion that can fit into the substrate recess SU of the substrate S. In the fixing device 45 of this embodiment, the substrate protrusion ST and substrate recess SU fit into the holder recess 70U and holder protrusion 70T, respectively, thereby positioning the substrate S, and therefore the heater 60, and the holder 70, and the heater 60 is held in the holder 70.

As shown in Figures 5 and 6, on the substrate S, the substrate protrusion ST and the substrate recess SU are arranged between the power supply terminal T and the heating pattern PH in the longitudinal direction LH. As shown in Figure 6, the dimension H1 of the power supply pattern PE in the width direction SH is smaller than the dimension H2 of the heating pattern PH in the width direction SH. Furthermore, the substrate recess SU is arranged within the region A in which the power supply pattern PE is formed in the longitudinal direction LH.

As shown in FIG. 7 , the connector 100 comprises a connector body 101 and a pair of clamping portions 102 and 103 that are provided continuously with the connector body 101 and are formed to sandwich the heater 60 and holder 70. The clamping portion 102 has two electrodes 104 that are electrically connected to terminals T1 and T2, respectively, of the power supply terminal T of the heater 60 when the connector 100 is attached to the heating unit 51 to sandwich the heater 60 and holder 70. The connector 100 is designed to supply power to the heater 60 via the electrodes 104.

[Method for manufacturing substrate S]
Next, a method for manufacturing the substrate S of the heater 60 will be specifically described with reference to Fig. 8. Fig. 8 is a diagram showing the method for manufacturing the substrate S of the heater 60.

As illustrated in Figure 8, for the substrates S of the heater 60, a manufacturing process is carried out in which multiple substrates S are manufactured from a single metal plate MP. In this manufacturing process, substrates S are manufactured, each having a substrate protrusion ST located at one end in a width direction SH perpendicular to the longitudinal direction LH of the substrate S and protruding in the width direction SH, and a substrate recess SU located at the other end in the width direction SH and recessed in the width direction SH with approximately the same shape as the substrate protrusion ST. Furthermore, in the manufacturing process, as shown in Figure 8, the substrate protrusion ST of one substrate S is formed, thereby forming a substrate recess SU of a substrate S adjacent to the one substrate S.

As described above, the fixing device 45, image forming apparatus 1, and heater 60 manufacturing method of this embodiment include a substrate S, a heater 60 having a resistance heating element P, and a holder 70 that holds the heater 60. The substrate S is located at one end in a width direction SH perpendicular to the longitudinal direction LH and has a substrate protrusion ST that protrudes in the width direction SH, and a substrate recess SU that is located at the other end in the width direction SH and has substantially the same shape as the substrate protrusion ST and is recessed in the width direction SH. The holder 70 has a holder recess 70U and a holder protrusion 70T that fit into the substrate protrusion ST and the substrate recess SU, respectively. As a result, this embodiment can prevent an increase in waste material during the manufacturing of the substrate S, as illustrated in FIG. 8, and can provide a cost-effective fixing device 45, image forming apparatus 1, and heater 60 manufacturing method that can improve the manufacturing yield of metal substrates S.

Furthermore, in the substrate S of this embodiment, the substrate protrusion ST and the substrate recess SU are located at approximately the same position in the longitudinal direction LH of the substrate S, which reliably prevents an increase in waste material during the manufacture of the substrate S. As a result, in this embodiment, the manufacturing yield of substrates S made of metal material can be reliably improved, and a cost-effective method for manufacturing the fixing device 45, image forming apparatus 1, and heater 60 can be easily constructed.

In this embodiment, the heater 60 has a power supply terminal T located at one end of the substrate S in the longitudinal direction LH, and a heating pattern PH that generates heat when power is supplied from the power supply terminal T. The substrate protrusion ST and substrate recess SU are located between the power supply terminal T and the heating pattern PH in the longitudinal direction LH. This makes it possible to position the substrate S relative to the holder 70 at a position close to the power supply terminal T, and prevents the power supply terminal T from shifting position even if thermal expansion occurs in the substrate S in the longitudinal direction LH due to heat generation.

In addition, in this embodiment, the heater 60 has a power supply pattern PE that electrically connects the power supply terminal T and the heating pattern PH. Furthermore, the dimension H1 of the power supply pattern PE in the width direction SH is smaller than the dimension H2 of the heating pattern PH in the width direction, and the substrate recess SU is disposed within the region A in the longitudinal direction LH where the power supply pattern PE is formed. This allows the dimension of the substrate S in the width direction SH to be reduced in this embodiment.

In the above explanation, the holder 70 is provided with a holder recess 70U and a holder protrusion 70T that fit into the substrate protrusion ST and substrate recess SU, respectively. However, this embodiment is not limited to this, and is not limited in any way as long as the holder 70 is provided with an engaging portion that engages with the substrate protrusion ST or substrate recess SU of the substrate S.

Specifically, for example, the holder 70 may be configured to have a holder recess 70U that is larger than the substrate protrusion ST and does not function as a positioning element. Also, the holder 70 may not have a holder protrusion 70T at a position that fits into the substrate recess SU. However, as in the above embodiment, providing the holder 70 with a holder recess 70U and a holder protrusion 70T that fit into the substrate protrusion ST and substrate recess SU, respectively, and positioning the holder 70 and heater 60 is preferable, as this improves the positioning accuracy between the holder 70 and heater 60.

Furthermore, in the above description, the power supply terminal T and the connector 100 electrically connected thereto are provided at one end of the longitudinal direction LH, but this embodiment is not limited to this, and the power supply terminal T and the connector 100 may be provided at both one end and the other end of the longitudinal direction LH.

This disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Configurations obtained by appropriately combining the technical means disclosed in the embodiments are also included in the technical scope of this disclosure.

1 Image forming apparatus 60 Heater S Substrate ST Substrate convex portion SU Substrate concave portion P Resistance heating element 70 Holder 70U Holder concave portion 70T Holder convex portion T Power supply terminal PH Heating pattern PE Power supply pattern LH Longitudinal direction SH Width direction MP Metal plate

Claims (2)

a heater having a substrate made of a metal material and a resistance heating element disposed on the substrate; and a holder for holding the heater;
the substrate has a substrate protrusion disposed at one end side in a width direction perpendicular to the longitudinal direction and protruding in the width direction, and a substrate recess disposed at the other end side in the width direction and recessed in the width direction in substantially the same shape as the substrate protrusion,
the holder has an engaging portion that engages with the substrate convex portion or the substrate concave portion, the engaging portion including a holder concave portion that can be fitted into the substrate convex portion and a holder convex portion that can be fitted into the substrate concave portion,
In the substrate, the substrate convex portion and the substrate concave portion are arranged at approximately the same position in the longitudinal direction of the substrate,
the heater includes a power supply terminal disposed at one end of the substrate in the longitudinal direction, a heat generating pattern that generates heat when power is supplied from the power supply terminal, and a power supply pattern that electrically connects the power supply terminal and the heat generating pattern,
the substrate protrusion and the substrate recess are disposed between the power supply terminal and the heat generating pattern in the longitudinal direction;
the power supply pattern has a smaller dimension in the width direction than the heat generation pattern;
the substrate recess is disposed within a region in the longitudinal direction in which the power supply pattern is formed,
a widthwise dimension of each of the power supply patterns being smaller than a widthwise dimension of each of the heat generating patterns; An image forming apparatus comprising the fixing device according to claim 1 .