Patent Description:
A heater configured to fix a toner is provided in an image forming apparatus such as a copier and a printer. In addition, the heater is also provided in a print erasure device provided in a rewritable card reader and writer, and the like. Typically, the heater includes an elongated substrate, a heat generation body that is provided on one surface of the substrate and extends in a longitudinal direction of the substrate, and a pair of terminals electrically connected to both ends of the heat generation body. In addition, the substrate may be provided with a thermistor for performing temperature control on the heat generation body.

Typically, the heat generation body is provided on one surface of the substrate, and the thermistor is provided on a surface of the substrate which is opposite to the surface provided with the heat generation body. However, in this configuration, heat of the heat generation body is less likely to be transferred to the thermistor, and thus there is a concern that temperature control accuracy of the heater deteriorates. Therefore, there is a concern that heat generation efficiency of the heat generation body may deteriorate.

In addition, the heat generation body and the thermistor may be provided on one surface of the substrate, and the heat generation body and the thermistor may be provided in parallel with each other in a lateral direction (width direction) of the substrate. However, when the heat generation body and the thermistor are simply provided in parallel with each other in the lateral direction of the substrate, the number of wirings which are provided on the one surface of the substrate and are connected to the heat generation body and the thermistor increases or dimensions of the substrate in the lateral direction are lengthened, and thus a reduction in size of the heater becomes difficult.

Here, there is a demand for development of a technology capable of accomplishing a reduction in size of the heater with a simple configuration. An example prior art heater is disclosed in <CIT>. The prior art heater appears to lack a wiring provided on the first insulation portion and the second insulation portion.

A heater according to an exemplary embodiment includes: a substrate that has electrical conductivity, and extends in a first direction; a first insulation portion that is provided on a first surface of the substrate, has an insulation property, and extends in the first direction; at least one heat generation body that is provided on the first insulation portion and extends in the first direction; a second insulation portion that is provided on a second surface of the substrate which is opposite to the first surface, has an insulation property, and extends in the first direction; at least one detection unit that is provided on at least one of the first insulation portion and the second insulation portion; and a first wiring which is provided on at least one of the first insulation portion and the second insulation portion and extends in the first direction, and in which one end is electrically connected to one terminal of the detection unit and the other end is electrically connected to the substrate having the electrical conductivity.

Hereinafter, an exemplary embodiment will be exemplified with reference to the accompanying drawings. Note that, in the drawings, the same reference numeral will be given to a similar constituent element, and detailed description will be appropriately omitted. In addition, arrows X, Y, and Z in the drawings represent three directions orthogonal to each other. For example, a longitudinal direction of a substrate is set as the X-direction (corresponding to an example of a first direction), a lateral direction (width direction) of the substrate is set as the Y-direction (corresponding to an example of a second direction), and a direction orthogonal to surfaces of the substrate is set as the Z-direction.

<FIG> is a schematic view when a heater <NUM> according to this embodiment is viewed from one side in a Z-direction.

<FIG> is a schematic view when the heater <NUM> is viewed from the other side in the Z-direction.

<FIG> is a schematic cross-sectional view of the heater <NUM> in a direction of line A-A in <FIG>.

As illustrated in <FIG>, for example, the heater <NUM> includes a substrate <NUM>, an insulation portion <NUM> (corresponding to an example of a first insulation portion), a heat generation body <NUM>, a detection unit <NUM>, a protective portion <NUM> (corresponding to an example of a first protective portion), and an insulation portion <NUM> (corresponding to an example of a second insulation portion).

The substrate <NUM> has a plate shape and includes a surface 10a (corresponding to an example of a first surface), and a surface 10b (corresponding to an example of a second surface) opposite to the surface 10a. The substrate <NUM> has a shape extending in one direction (for example, the X-direction). For example, a planar shape of the substrate <NUM> is an elongated rectangular shape. For example, the thickness of the substrate <NUM> is approximately <NUM> to <NUM>. For example, a width dimension W (a dimension in a lateral direction; a dimension in the Y-direction) of the substrate <NUM> is approximately <NUM> to <NUM>. A length L (a dimension in a longitudinal direction; a dimension in the X-direction) of the substrate <NUM> can be appropriately changed in correspondence with a size of a heating object (for example, paper) or the like.

The substrate <NUM> is formed from a material having heat resistance and electrical conductivity. Typically, a substrate is formed from ceramics such as an aluminum oxide, but the heater <NUM> according to this embodiment is provided with the substrate <NUM> containing a metal. Examples of the metal include stainless steel, an aluminum alloy, and the like.

As illustrated in <FIG> and <FIG>, the insulation portion <NUM> has an insulation property, and is provided on the surface 10a of the substrate <NUM>. The insulation portion <NUM> is provided to insulate the substrate <NUM> having electrical conductivity, and the heat generation body <NUM> and the detection unit <NUM>. Accordingly, the insulation portion <NUM> is provided in a shape covering a region where the heat generation body <NUM> and the detection unit <NUM> are provided on the surface 10a of the substrate <NUM>. In addition, the insulation portion <NUM> is provided with a hole 20a passing through the insulation portion <NUM> in a thickness direction. The insulation portion <NUM> is formed from a material having heat resistance and an insulation property. For example, the insulation portion <NUM> can be formed from inorganic materials such as ceramics and glass materials. For example, the insulation portion <NUM> can be formed by thermal spraying or firing.

The heat generation body <NUM> converts applied electric power to heat (joule heat). The heat generation body <NUM> is provided on the insulation portion <NUM> (a surface of the insulation portion <NUM> on a side opposite to the substrate <NUM> side). For example, the heat generation body <NUM> extends in the X-direction. A plurality of the heat generation bodies <NUM> can be provided. For example, the plurality of heat generation bodies <NUM> are provided in parallel with each other in the Y-direction with a predetermined interval. For example, as illustrated in <FIG> and <FIG>, a pair of the heat generation bodies <NUM> can be provided.

For example, each of the heat generation bodies <NUM> is formed by using a ruthenium oxide (RuO<NUM>), a silver-palladium (Ag-Pd) alloy, or the like. For example, the heat generation body <NUM> can be formed by applying a paste-shape material onto the insulation portion <NUM> by using a screen print method or the like, and by hardening the material by using a firing method or the like.

In addition, a wiring <NUM> that electrically connects the plurality of heat generation bodies <NUM> can be provided. The wiring <NUM> is provided on the insulation portion <NUM>. At least one wiring <NUM> can be provided. For example, as illustrated in <FIG> and <FIG>, the wiring <NUM> extends in the Y-direction, and is electrically connected to one end of the pair of heat generation bodies <NUM>.

In addition, a terminal <NUM> (corresponding to an example of a second terminal) for electrically connecting the heat generation body <NUM> to an external device or the like can be provided. The terminal <NUM> is electrically connected to one end of the heat generation bodies <NUM>. For example, a pair of the terminals <NUM> can be provided. The pair of terminals <NUM> are provided on the insulation portion <NUM>. For example, as illustrated in <FIG> and <FIG>, in the X-direction, the pair of terminals <NUM> are electrically connected to ends of the heat generation bodies <NUM> on a side opposite to a side where the wiring <NUM> is provided. For example, the pair of terminals <NUM> can be provided in parallel with each other in the Y-direction with a predetermined interval. In addition, a wiring that electrically connects each of the terminals <NUM> and each of the heat generation bodies <NUM> can also be provided. When the wiring is provided between the terminal <NUM> and the heat generation body <NUM>, the pair of terminals <NUM> can be provided at any position.

For example, the wiring <NUM> and the terminal <NUM> are formed by using a material containing silver, copper, or the like. For example, the wiring <NUM> and the terminal <NUM> can be formed by applying a paste-shaped material onto the insulation portion <NUM> by using a screen print method or the like, and by hardening the material by using a firing method or the like. When providing the wiring between the terminal <NUM> and the heat generation body <NUM>, a material and a forming method of the wiring can be set to be similar to a material and a forming method of the wiring <NUM> and the terminal <NUM>.

The detection unit <NUM> detects a temperature of the heat generation body <NUM>. For example, the detection unit <NUM> may be set as a thermistor, a thermocouple, a temperature measuring resistor, or the like. The detection unit <NUM> exemplified in <FIG> is a thermistor. The detection unit <NUM> is provided on the insulation portion <NUM>. In the Y-direction, the detection unit <NUM> can be provided in parallel with the heat generation body <NUM>. For example, as illustrated in <FIG>, the detection unit <NUM> can be provided between the heat generation bodies <NUM>. In the X-direction, the detection unit <NUM> can be provided, for example, at a position in the vicinity of the center of the heat generation body <NUM>. In the Y-direction, the detection unit <NUM> can be provided, for example, at a position in the vicinity of the center between the heat generation bodies <NUM>. When the detection unit <NUM> is provided at the position, a distance between one of the heat generation bodies <NUM> and the detection unit <NUM> becomes approximately the same as a distance between the other heat generation body <NUM> and the detection unit <NUM>. Accordingly, a variation in an in-plane temperature of the heater <NUM> can be suppressed from occurring.

In addition, a wiring <NUM> (corresponding to an example of a first wiring), a wiring <NUM> (corresponding to an example of a second wiring), and a terminal <NUM> (corresponding to an example of a first terminal) which are electrically connected to the detection unit <NUM> can be provided. The wiring <NUM>, the wiring <NUM>, and the terminal <NUM> are provided on the insulation portion <NUM>. For example, as illustrated in <FIG>, the wiring <NUM> and the wiring <NUM> extend in the X-direction. In the Y-direction, the wiring <NUM>, the wiring <NUM>, and the terminal <NUM> are provided between the heat generation bodies <NUM>.

One end of the wiring <NUM> is electrically connected to one terminal of the detection unit <NUM>. The other end of the wiring <NUM> is electrically connected to the surface 10a of the substrate <NUM> through the hole 20a of the insulation portion <NUM>.

One end of the wiring <NUM> is electrically connected to the other terminal of the detection unit <NUM>. The other end of the wiring <NUM> is electrically connected to the terminal <NUM>. In the X-direction, the wiring <NUM> and the terminal <NUM> are provided on a side of the detection unit <NUM> which is opposite to the wiring <NUM> side. In the Y-direction, the terminal <NUM> may be provided in parallel with the terminal <NUM>.

A material and a forming method of the wiring <NUM>, the wiring <NUM>, and the terminal <NUM> may be set to be similar to the material and the forming method of the wiring <NUM> and the terminal <NUM>. In addition, the wiring <NUM>, the terminal <NUM>, the wiring <NUM>, the wiring <NUM>, and the terminal <NUM> can be formed simultaneously in the same forming process.

As illustrated in <FIG> and <FIG>, the protective portion <NUM> is provided on the insulation portion <NUM>, and extends in the X-direction. For example, the protective portion <NUM> covers the heat generation body <NUM>, the wiring <NUM>, the detection unit <NUM>, the wiring <NUM>, and the wiring <NUM>. A dimension of the protective portion <NUM> in the X-direction can be made smaller than a dimension of the insulation portion <NUM>. For example, the terminal <NUM> and the terminal <NUM> are exposed from the protective portion <NUM>.

In addition, as illustrated in <FIG>, in the X-direction, the vicinity of an end of the surface 10a of the substrate <NUM> on a side where the terminal <NUM> and the terminal <NUM> are provided is exposed from the insulation portion <NUM>. As described above, the substrate <NUM> is formed from a material having electrical conductivity. In addition, an end of the wiring <NUM> is electrically connected to the surface 10a of the substrate <NUM> through the hole 20a of the insulation portion <NUM>. According to this, the substrate <NUM> functions as a wiring and a terminal which are electrically connected to the wiring <NUM>. For example, as illustrated in <FIG>, the vicinity of the end of the substrate <NUM> on a side where the terminal <NUM> and the terminal <NUM> are provided functions as a terminal 43a that is electrically connected to the wiring <NUM>.

In the X-direction, when the terminal <NUM>, the terminal <NUM>, and the terminal 43a are provided in the vicinity of one end of the substrate <NUM>, a harness connector for electrical connection with an external device can be mounted on one end of the heater <NUM>. According to this, a wiring space of the heater <NUM> can be reduced, or wiring time of the heater <NUM> can be shortened.

In addition, the substrate <NUM> having electrical conductivity functions as a wiring that is electrically connected to the wiring <NUM>, and thus it is not necessary to fold back the wiring <NUM> to the terminal <NUM> side. Accordingly, in the Y-direction, it is possible to reduce a space necessary for providing the detection unit <NUM>. When the space necessary for providing the detection unit <NUM> is reduced, dimensions between the heat generation bodies <NUM> can be reduced. Accordingly, a reduction in size of the heater <NUM> is accomplished, or uniformity of an in-plane temperature of the heater <NUM> can be easily accomplished.

For example, the protective portion <NUM> has a function of insulating the heat generation body <NUM>, the wiring <NUM>, the detection unit <NUM>, the wiring <NUM>, and the wiring <NUM>, a function of transferring heat generated in the heat generation body <NUM> to the outside, and a function of protecting the heat generation body <NUM> and the like from an external force, a corrosive gas, and the like. The protective portion <NUM> is formed from a material that has heat resistance and an insulation property, and has high chemical stability and heat conductivity. For example, the protective portion <NUM> is formed from inorganic materials such as ceramics and a glass material. In this case, the protective portion <NUM> can be formed by using a glass material to which a filler containing a material such as an aluminum oxide with high heat conductivity is added. The heat conductivity of the glass material to which the filler is added can be set to, for example, <NUM> [Wj(m·K)] or more.

For example, the protective portion <NUM> can be formed by applying a paste-shaped material onto the insulation portion <NUM>, the heat generation body <NUM>, the wiring <NUM>, the detection unit <NUM>, the wiring <NUM>, and the wiring <NUM> by using a screen print method or the like, and by hardening the material by using a firing method or the like.

The insulation portion <NUM> is provided to insulate the surface 10b side of the substrate <NUM> having electrical conductivity. For example, the thickness, a material, and a forming method of the insulation portion <NUM> can be set to be the same as the thickness, the material, and the forming method of the insulation portion <NUM> as described above.

Note that, the thickness of the insulation portion <NUM> can be made larger than the thickness of the insulation portion <NUM>. For example, a thermal stress occurs due to a difference in a coefficient of thermal expansion of materials when using the heater <NUM>, or when manufacturing the heater <NUM> (for example, when firing the protective portion <NUM> or the like). Therefore, there is a concern that warpage may occur in the heater <NUM> due to the thermal stress. When the warpage occurs in the heater <NUM>, there is a concern that a distance between the heater <NUM> and an object to be heated varies, and heating unevenness may occur in the object to be heated.

In this case, a thermal stress generated due to the substrate <NUM>, the insulation portion <NUM>, and the protective portion <NUM> on the surface 10a side of the substrate <NUM> can be cancelled by a thermal stress generated due to the substrate <NUM> and the insulation portion <NUM> on the surface 10b side of the substrate <NUM>. When the thermal stress is cancelled, warpage can be suppressed from occurring in the heater <NUM>. In this case, when the thickness of the insulation portion <NUM> is made larger, a value of the thermal stress occurring on the surface 10b side of the substrate <NUM> can be made close to a value of the thermal stress occurring on the surface 10a side of the substrate <NUM>. According to this, warpage can be more effectively suppressed from occurring in the heater <NUM>. For example, the thickness of the insulation portion <NUM> can be set to a value that is approximately the sum of the thickness of the insulation portion <NUM> and the thickness of the protective portion <NUM>.

<FIG> is a schematic view when a heater <NUM> according to a comparative example is viewed from one side in the Z-direction.

<FIG> is a schematic view when the heater <NUM> according to the comparative example is viewed from the other side in the Z-direction.

As illustrated in <FIG> and <FIG>, the heater <NUM> includes the substrate <NUM>, an insulation portion 20b, the heat generation body <NUM>, the detection unit <NUM>, the protective portion <NUM>, and the insulation portion <NUM>.

The insulation portion 20b is provided on the surface 10a of the substrate <NUM> as in the above-described insulation portion <NUM>. Dimensions, a planar shape, a material, and the like of the insulation portion 20b can be set to be similar as in the insulation portion <NUM> as described above. However, the insulation portion 20b is not provided with the hole 20a.

In the heater <NUM> exemplified in <FIG>, the detection unit <NUM> is provided on the surface 10a side of the substrate <NUM>. In contrast, in the heater <NUM>, as illustrated in <FIG>, the detection unit <NUM> is provided on the surface 10b side of the substrate <NUM>. Accordingly, it is necessary to provide the insulation portion 20b also on the surface 10b of the substrate <NUM>.

In this case, since the heat generation body <NUM> is provided on the surface 10a side of the substrate <NUM>, heat of the heat generation body <NUM> is less likely to be transferred to the detection unit <NUM>. When the heat of the heat generation body <NUM> is less likely to be transferred to the detection unit <NUM>, temperature control accuracy of the heater <NUM> (heat generation body <NUM>) becomes low.

Therefore, in the Y-direction, a position of the detection unit <NUM> is set to be the same as a position of the heat generation body <NUM>. In this configuration, a distance between the detection unit <NUM> and the heat generation body <NUM> can be shortened, and thus the temperature control accuracy of the heater <NUM> (heat generation body <NUM>) can be improved. However, in this case, the same number of detection units <NUM> as the number of heat generation bodies <NUM> are necessary. In addition, when the number of the detection units <NUM> increases, a wiring <NUM> that electrically connecting the detection units <NUM> is necessary or the number of the wiring <NUM> and the terminal <NUM> increases. Note that, a material and a forming method of the wiring <NUM> can be set to be similar to the material and the forming method of the wiring <NUM> as described above. In addition, as described above, it is necessary to provide the insulation portion 20b also on the surface 10b of the substrate <NUM>.

Therefore, an increase in the manufacturing cost of the heater <NUM> is caused.

<FIG> is a schematic view when a heater <NUM> according to another comparative example is viewed from one side in the Z-direction.

Note that, an aspect when the heater <NUM> is viewed from the other side in the Z-direction can be set to be similar as in <FIG>. However, as to be described later, a width dimension W1 of a substrate <NUM> becomes larger than the width dimension W of the substrate <NUM>.

As illustrated in <FIG>, the heater <NUM> includes the substrate <NUM>, the insulation portion 20b, the heat generation body <NUM>, the detection unit <NUM>, the protective portion <NUM>, and the insulation portion <NUM>.

As illustrated in <FIG>, a length L, the thickness, a planar shape, a material, and the like of the substrate <NUM> can be set to be similar as in the above-described substrate <NUM>. However, the width dimension W1 of the substrate <NUM> is larger than the width dimension W of the substrate <NUM>.

The insulation portion 20b is provided on a surface 103a of the substrate <NUM>. The insulation portion <NUM> is provided on a surface 103b of the substrate <NUM> which is opposite to the surface 103a.

As illustrated in <FIG>, in the above-described heater <NUM>, the detection unit <NUM> is provided between the heat generation bodies <NUM> in the Y-direction. In contrast, in the heater <NUM>, the detection unit <NUM> is provided on an outer side of a pair of the heat generation bodies <NUM> in the Y-direction. In addition, the wiring <NUM>, a wiring <NUM>, a wiring <NUM>, the wiring <NUM>, and the terminal <NUM> which are electrically connected to the detection unit <NUM> are provided. The wiring <NUM> and the wiring <NUM> extend in the X-direction. The wiring <NUM> is provided in parallel with the wiring <NUM> and the wiring <NUM>. One end of the wiring <NUM> is electrically connected to a terminal of the detection unit <NUM> which is different from the terminal to which the wiring <NUM> is connected. The other end of the wiring <NUM> is electrically connected to the wiring <NUM>. One end of the wiring <NUM> is electrically connected to the wiring <NUM>. The other end of the wiring <NUM> is electrically connected to the terminal <NUM>. A pair of the terminals <NUM> are provided. In the Y-direction, the pair of terminals <NUM> are provided in parallel with a pair of the terminals <NUM>.

Here, in the Y-direction, when the detection unit <NUM> is provided on an outer side of the pair of heat generation bodies <NUM>, a distance between one of the heat generation bodies <NUM> and the detection unit <NUM> becomes larger than a distance between the other heat generation unit <NUM> and the detection unit <NUM>. According to this, temperature control accuracy with respect to the pair of heat generation bodies <NUM> is lowered. In addition, since the width dimension W1 of the substrate <NUM> becomes larger than the width dimension W of the substrate <NUM>, a reduction in size of the heater <NUM> becomes difficult.

In contrast, in the heater <NUM> according to this embodiment, the heat generation body <NUM> and the detection unit <NUM> are provided on a surface of the substrate <NUM> on the same side. In addition, in the Y-direction, the detection unit <NUM> is provided between the heat generation bodies <NUM>. According to this, a distance between the heat generation bodies <NUM> and the detection unit <NUM> can be shortened, and a distance between the detection unit <NUM> and one of the heat generation bodies <NUM> can be set to be substantially the same as a distance between the detection unit <NUM> and the other heat generation body <NUM>. According to this, the temperature control accuracy with respect to the heat generation bodies <NUM> can be raised, and thus evenness of an in-plane temperature of the heater <NUM> can be accomplished.

In addition, since the heat generation body <NUM>, the wiring <NUM>, the terminal <NUM>, the detection unit <NUM>, the wiring <NUM>, the wiring <NUM>, and the terminal <NUM> are provided on one side of the substrate <NUM>, simplification of a manufacturing process can be accomplished.

In addition, since the substrate <NUM> having electrical conductivity can be set as a wiring that is electrically connected to the wiring <NUM>, it is not necessary to fold back the wiring <NUM> to the terminal <NUM> side. Accordingly, in the Y-direction, a space necessary for providing the detection unit <NUM> can be reduced, and thus the width dimension W of the substrate <NUM> can be reduced. When the width dimension W of the substrate <NUM> is reduced, a reduction in size of the heater <NUM> can be accomplished.

<FIG> is a schematic view when a heater 1a according to another embodiment is viewed from one side in the Z-direction.

<FIG> is a schematic view when the heater 1a is viewed from the other side in the Z-direction.

<FIG> is a schematic cross-section view of the heater 1a in <FIG> in a direction of line B-B.

As illustrated in <FIG>, for example, the heater 1a includes the substrate <NUM>, the insulation portion <NUM> (corresponding to an example of a first insulation portion), the heat generation body <NUM>, the wiring <NUM>, the protective portion <NUM>, the insulation portion <NUM> (corresponding to an example of a second insulation portion), a detection unit <NUM>, a wiring <NUM>, and a protective portion <NUM>.

The detection unit <NUM> detects a temperature of the substrate <NUM>. The detection unit <NUM> may be set to be similar as the above-described detection unit <NUM>. At least one of the detection units <NUM> is provided on the insulation portion <NUM>. Two pieces of the detection units <NUM> are provided in the heater 1a exemplified in <FIG>.

As illustrated in <FIG>, a plurality of the detection units <NUM> are provided in a longitudinal direction (X-direction) of the substrate <NUM> and in a lateral direction (Y-direction) of the substrate <NUM> with a predetermined interval. When the plurality of detection units <NUM> are provided in the longitudinal direction (X-direction) of the substrate <NUM> and the lateral direction (Y-direction) of the substrate <NUM> with a predetermined interval, a variation in an in-plane temperature of the substrate <NUM>, and a variation in an in-plane temperature of the heater 1a can be detected. Accordingly, for example, electric power applied to the heat generation bodies <NUM> can be controlled so that a variation of the temperature in the longitudinal direction (X-direction) of the substrate <NUM> decreases. The number, an interval, arrangement, and the like of the detection units <NUM> can be appropriately changed in correspondence with the size of the heater 1a (substrate <NUM>), specifications (for example, a heating temperature or a permissible temperature variation range) of the heater 1a, and the like. The number, the interval, the arrangement, and the like of the detection units <NUM> can be appropriately determined, for example, by performing an experiment or a simulation.

As illustrated in <FIG>, for example, the wiring <NUM> includes a terminal <NUM> (corresponding to an example of a fourth terminal) and wirings 82a to 82d. The terminal <NUM>, and the wirings 82a to 82d can be integrally formed. For example, a material and a forming method of the wiring <NUM> can be set to be similar to the material and the forming method of the wiring <NUM> as described above. The number of the terminal <NUM> and the number of the wirings 82a to 82d can be appropriately changed in correspondence with the number of the detection units <NUM>.

For example, one terminal <NUM> can be provided with respect to one detection unit <NUM>. The terminal <NUM> is electrically connected to the detection unit <NUM>. In the heater 1a exemplified in <FIG>, since two detection units <NUM> are provided, two terminals <NUM> are provided. The two terminals <NUM> are provided on the insulation portion <NUM> in the vicinity of an end of the substrate <NUM> on a side where terminals <NUM> (corresponding to an example of a third terminal) are provided. The two terminals <NUM> can be provided in parallel with each other in the lateral direction (Y-direction) of the substrate <NUM> with a predetermined interval. That is, in the heater 1a according to this embodiment, the two terminals <NUM> are integrated in the vicinity of one end of the substrate <NUM>.

Note that, details of the wirings 82a to 82d will be described later.

As illustrated in <FIG>, for example, the protective portion <NUM> is provided on the insulation portion <NUM> and covers the detection unit <NUM> and the wirings 82a to 82d. In this case, the terminals <NUM> are exposed from the protective portion <NUM>.

For example, the protective portion <NUM> has a function of insulating the detection unit <NUM> and the wirings 82a to 82d, and a function of protecting the detection unit <NUM> and the wirings 82a to 82d from an external force, a corrosive gas, and the like. A material and a forming method of the protective portion <NUM> can be set to be similar to the material and the forming method of the protective portion <NUM> as described above.

Here, a thermal stress occurs due to a difference in a coefficient of thermal expansion of materials when using the heater 1a, or when manufacturing the heater 1a (for example, when firing the protective portion <NUM> or the like). Therefore, there is a concern that warpage may occur in the heater 1a due to the thermal stress. When the warpage occurs in the heater 1a, there is a concern that a distance between the heater 1a and an object to be heated varies, and heating unevenness may occur in the object to be heated.

In the heater 1a according to this embodiment, as illustrated in <FIG>, the insulation portion <NUM>, the heat generation body <NUM>, the wiring <NUM>, and the protective portion <NUM> are provided on the surface 10a side of the substrate <NUM>. The insulation portion <NUM>, the detection unit <NUM>, the wiring <NUM>, and the protective portion <NUM> are provided on the surface 10b side of the substrate <NUM>. In addition, a material of the insulation portion <NUM> can be set to be similar to the material of the insulation portion <NUM>. A material of the protective portion <NUM> can be set to be the same as the material of the protective portion <NUM>.

Accordingly, a thermal stress generated due to the substrate <NUM>, the insulation portion <NUM>, and the protective portion <NUM> on the surface 10a side of the substrate <NUM> can be cancelled by a thermal stress generated due to the substrate <NUM>, the insulation portion <NUM>, and the protective portion <NUM> on the surface 10b side of the substrate <NUM>. When the thermal stress is cancelled, warpage can be suppressed from occurring in the heater 1a.

For example, when the thickness of the insulation portion <NUM> and the thickness of the insulation portion <NUM> are set to be approximately the same as each other, and the thickness of the protective portion <NUM> and the thickness of the protective portion <NUM> are set to be approximately the same as each other, a value of the thermal stress generated on the surface 10a side of the substrate <NUM> and a value of the thermal stress generated on the surface 10b side of the substrate <NUM> can be set to be approximately the same as each other. According to this, warpage can be effectively suppressed from occurring in the heater 1a.

In addition, for example, even when a value of the sum of the thickness of the insulation portion <NUM> and the thickness of the protective portion <NUM>, and a value of the sum of the thickness of the insulation portion <NUM> and the thickness of the protective portion <NUM> are set to be approximately the same as each other, the value of the thermal stress generated on the surface 10a side of the substrate <NUM> and the value of the thermal stress generated on the surface 10b side of the substrate <NUM> can be set to be approximately the same as each other. According to this, warpage can be effectively suppressed from occurring in the heater 1a.

Next, the wirings 82a to 82d will be further described.

First, description will be given of a wiring of the detection unit <NUM> according to a comparative example.

<FIG> is a schematic view exemplifying wiring of the detection units <NUM> according to the comparative example.

As illustrated in <FIG>, an insulation portion <NUM> has an insulation property and is provided on the surface 11b of the substrate <NUM>. The detection units <NUM> are provided on the insulation portion <NUM>. The number, an interval, and an arrangement of the detection units <NUM> can be set to be similar as in the exemplification in <FIG>.

Three terminals <NUM> are provided. One of the three terminals <NUM> is set to be common to two detection units <NUM>. The three terminals <NUM> are provided in the vicinity of an end of the substrate <NUM> on one side in the longitudinal direction (X-direction). The three terminals <NUM> are provided in parallel with each other in the lateral direction (Y-direction) of the substrate <NUM> with a predetermined interval.

One of the detection units <NUM> is electrically connected to one of the terminals <NUM> through a wiring 84a. The other detection unit <NUM> is electrically connected to another terminal <NUM> through a wiring 84b. In addition, the two detection units <NUM> are electrically connected to the remaining terminal <NUM> through a common wiring 84c.

The two detection units <NUM> and the wirings 84a to 84c are covered with a protective portion <NUM>. The three terminals <NUM> are exposed from the protective portion <NUM>.

Even in this aspect, the two detection units <NUM> can be wired. However, in this aspect, as can be seen from <FIG>, the three wirings 84a to 84c extending in the longitudinal direction (X-direction) of the substrate <NUM> are arranged in parallel in the lateral direction (Y-direction) of the substrate <NUM>. Therefore, the width dimension W1 (a dimension in the lateral direction; a dimension in the Y-direction) of the substrate <NUM> increases. When the width dimension W1 of the substrate <NUM> increases, it is difficult to accomplish a reduction in size of the heater.

Here, in the heater 1a according to this embodiment, the substrate <NUM> having electrical conductivity is set as a wiring common to the two detection units <NUM>.

As illustrated in <FIG>, the wiring 82a is provided on the insulation portion <NUM>, and is electrically connected to one of the terminals <NUM> and one of the detection units <NUM>. The wiring 82b is provided on the insulation portion <NUM> and one end of the wiring 82b is electrically connected to the detection unit <NUM> to which the wiring 82a is electrically connected. The wiring 82b extends in the longitudinal direction (X-direction) of the substrate <NUM>, and an end opposite to the detection unit <NUM> side is electrically connected to the substrate <NUM> on an outer side of the insulation portion <NUM>.

The wiring 82c is provided on the insulation portion <NUM> and is electrically connected to the other terminal <NUM> and the other detection unit <NUM>. The wiring 82d is provided on the insulation portion <NUM> and one end of the wiring 82d is electrically connected to the detection unit <NUM> to which the wiring 82c is electrically connected. The wiring 82d extends in the longitudinal direction (X-direction) of the substrate <NUM> and an end opposite to the detection unit <NUM> side is electrically connected to the substrate <NUM> on an outer side of the insulation portion <NUM>.

A material and a forming method of the terminals <NUM> and the wirings 82a to 82d can be set to be similar to the material and the forming method of the terminals <NUM> and the wiring <NUM> as described above.

In addition, as illustrated in <FIG>, in the longitudinal direction (X-direction) of the substrate <NUM>, the vicinity of an end of the surface 10b of the substrate <NUM> on a side where the terminals <NUM> are provided is exposed from the insulation portion <NUM>. As described above, the substrate <NUM> is formed from a material having electrical conductivity. In addition, ends of the wirings 82b and 82d are electrically connected to the surface 10b of the substrate <NUM> on an outer side of the insulation portion <NUM>. According to this, the substrate <NUM> functions as a wiring and a terminal which are electrically connected to the detection units <NUM> (wirings 82b and 82d). For example, as illustrated in <FIG>, the vicinity of an end of the substrate <NUM> on a side where the terminals <NUM> are provided functions as a terminal 81a that is electrically connected to the detection units <NUM> through the wirings 82b and 82d.

As illustrated in <FIG>, in the longitudinal direction (X-direction) of the substrate <NUM>, when the terminals <NUM>, the terminals <NUM>, and the terminal 81a are provided in the vicinity of an end of the substrate <NUM> on the same side, the heater <NUM> and an external device can be electrically connected with one harness. According to this, simplification of routing of the harness, a reduction in a wiring space, easiness of wiring of the harness, shortening of wiring time, and the like can be accomplished.

In addition, since the substrate <NUM> having electrical conductivity functions as a wiring that is electrically connected to the detection units <NUM> (the wirings 82b and 82d), it is not necessary to fold back the wirings 82b and 82d to the terminal <NUM> side. Accordingly, the dimension of the substrate <NUM> in the lateral direction (Y-direction) can be reduced, and thus a reduction in size of the heater <NUM> can be accomplished.

<FIG> is a schematic view when a heater 1b according to another embodiment is viewed from one side in the Z-direction.

<FIG> is a schematic view when the heater 1b is viewed from the other side in the Z-direction.

As illustrated in <FIG>, for example, the heater 1b includes the substrate <NUM>, the insulation portion <NUM>, heat generation bodies <NUM>, 30a, and 30b, a wiring <NUM>, the protective portion <NUM>, the insulation portion <NUM>, the detection unit <NUM>, a wiring <NUM>, and the protective portion <NUM>.

That is, in the heater 1b, the heat generation bodies 30a and 30b are added to the above-described heater 1a, and four pieces of the detection units <NUM> are provided.

The heat generation bodies <NUM>, 30a, and 30b are provided in parallel with each other in the lateral direction (Y-direction) of the substrate <NUM> with a predetermined interval. The length of the heat generation bodies 30a and 30b in the longitudinal direction (X-direction) of the substrate <NUM> is shorter than the length of the heat generation body <NUM>. In the lateral direction (Y-direction) of the substrate <NUM>, the heat generation body 30a is provided on one side of the heat generation body <NUM>, and the heat generation body 30b is provided on the other side of the heat generation body <NUM>. In the longitudinal direction (X-direction) of the substrate <NUM>, the heat generation body 30a is provided in the vicinity of an end of the heat generation body <NUM> on a side opposite to a terminal <NUM> side. The heat generation body 30b is provided in the vicinity of an end of the heat generation body <NUM> on a terminal <NUM> side. For example, a material and a forming method of the heat generation bodies 30a and 30b can be set to be similar to the material and the forming method of the heat generation body <NUM> as described above.

Terminals <NUM> and the wiring <NUM> are provided on the insulation portion <NUM>. The terminals <NUM> and the wiring <NUM> can be integrally formed. For example, a material and a forming method of the terminals <NUM> and the wiring <NUM> can be set to be similar to the material and the forming method of the terminals <NUM> and the wiring <NUM> as described above.

Four pieces of the terminals <NUM> are provided. One terminal <NUM> is provided with respect to each of the heat generation bodies <NUM>, 30a, and 30b. In addition, one terminal <NUM> common to the heat generation bodies <NUM>, 30a, and 30b is provided. The four terminals <NUM> are provided in the vicinity of one end of the substrate <NUM> in the longitudinal direction (X-direction). The four terminals <NUM> can be provided in parallel with each other in the lateral direction (Y-direction) of the substrate <NUM> with a predetermined interval. That is, in the heater 1b, the four terminals <NUM> are integrated in the vicinity of the one end of the substrate <NUM>.

The wiring <NUM> includes a portion 42a1, a portion 42b, a portion 42b1, and a portion 42b2. The portion 42a1 is provided in the vicinity of an end of the substrate <NUM> on a side opposite to a side where the terminals <NUM> are provided in the longitudinal direction (X-direction) of the substrate <NUM>. The portion 42a1 extends in the lateral direction (Y-direction) of the substrate <NUM>.

The portion 42b is provided in the vicinity of a peripheral edge of the substrate <NUM> in the lateral direction (Y-direction) of the substrate <NUM>. The portion 42b extends in the longitudinal direction (X-direction) of the substrate <NUM> and is electrically connected to one of the terminals <NUM> and the portion 42a1.

The portion 42b1 extends in the longitudinal direction (X-direction) of the substrate <NUM> and is electrically connected to the heat generation body 30b and the portion 42a1. An end of the heat generation body 30b on a side opposite to a side to which the portion 42b1 is electrically connected is electrically connected to one of the terminals <NUM>. The terminal <NUM> and the heat generation body 30b may be directly connected or a wiring may be provided between the terminal <NUM> and the heat generation body 30b.

The portion 42b2 extends in the longitudinal direction (X-direction) of the substrate <NUM> and is electrically connected to the heat generation body 30a and one of the terminals <NUM>.

The heat generation body <NUM> extends in the longitudinal direction (X-direction) of the substrate <NUM> and is electrically connected to one of the terminals <NUM> and the portion 42a1. The terminal <NUM> and the heat generation body <NUM> may be directly connected or a wiring may be provided between the terminal <NUM> and the heat generation body <NUM>. The portion 42a1 and the heat generation body <NUM> may be directly connected or a wiring may be provided between the portion 42a1 and the heat generation body <NUM>.

For example, the protective portion <NUM> is provided on the insulation portion <NUM> and covers the heat generation bodies <NUM>, 30a, and 30b, and the wiring <NUM> (the portion 42a1, the portion 42b, the portion 42b1, and the portion 42b2). In this case, the terminals <NUM> are exposed from the protective portion <NUM>.

As illustrated in <FIG>, four pieces of the detection units <NUM> are provided on the insulation portion <NUM>. The four detection units <NUM> are provided in the longitudinal direction (X-direction) of the substrate <NUM> and the lateral direction (Y-direction) of the substrate <NUM> with a predetermined interval.

The wiring <NUM> includes four terminals <NUM> and wirings 82a to <NUM>. The four terminals <NUM> and the wirings 82a to <NUM> can be integrally formed. For example, a material and a forming method of the wiring <NUM> can be set to be similar to the material and the forming method of the wiring <NUM> as described above. The number of the terminals <NUM> and the number of the wirings 82a to <NUM> can be appropriately changed in correspondence with the number of the detection units <NUM>.

For example, one of the terminals <NUM> can be provided with respect to one of the detection units <NUM>. In the heater 1b exemplified in <FIG>, since four detection units <NUM> are provided, four terminals <NUM> are provided. The four terminals <NUM> are provided in the vicinity of an end on a side where the four terminals <NUM> are provided in the longitudinal direction (X-direction) of the substrate <NUM>. The four terminals <NUM> can be provided in parallel with each other in the lateral direction (Y-direction) of the substrate <NUM> with a predetermined interval. That is, in the heater 1b, the four terminals <NUM> are integrated in the vicinity of one end of the substrate <NUM>.

The wiring 82a is provided on the insulation portion <NUM> and is electrically connected to one of the terminals <NUM> and one of the detection units <NUM>. The wiring 82b is provided on the insulation portion <NUM> and one end of the wiring 82b is electrically connected to the detection unit <NUM> to which the wiring 82a is electrically connected. The wiring 82b extends in the longitudinal direction (X-direction) of the substrate <NUM>, and an end on a side opposite to a detection unit <NUM> side is electrically connected to the substrate <NUM> on an outer side of the insulation portion <NUM>.

The wiring 82c is provided on the insulation portion <NUM> and is electrically connected to one of the terminals <NUM> and one of the detection units <NUM>. The wiring 82d is provided on the insulation portion <NUM> and one end of the wiring 82d is electrically connected to the detection unit <NUM> to which the wiring 82c is electrically connected. The wiring 82d extends in the longitudinal direction (X-direction) of the substrate <NUM>, and an end on a side opposite to the detection unit <NUM> side is electrically connected to the substrate <NUM> on an outer side of the insulation portion <NUM>.

The wiring 82e is provided on the insulation portion <NUM> and is electrically connected to one of the terminals <NUM> and one of the detection units <NUM>. The wiring 82f is provided on the insulation portion <NUM> and one end of the wiring 82f is electrically connected to the detection unit <NUM> to which the wiring 82e is electrically connected. The wiring 82f extends in the longitudinal direction (X-direction) of the substrate <NUM>, and an end on a side opposite to the detection unit <NUM> side is electrically connected to the substrate <NUM> on an outer side of the insulation portion <NUM>.

The wiring <NUM> is provided on the insulation portion <NUM> and is electrically connected to one of the terminals <NUM> and one of the detection units <NUM>. The wiring <NUM> is provided on the insulation portion <NUM>, and one end of the wiring <NUM> is electrically connected to the detection unit <NUM> to which the wiring <NUM> is electrically connected. The wiring <NUM> extends in the longitudinal direction (X-direction) of the substrate <NUM>, and an end on a side opposite to the detection unit <NUM> side is electrically connected to the substrate <NUM> on an outer side of the insulation portion <NUM>.

A material and a forming method of the terminals <NUM> and the wirings 82a to <NUM> can be set to be similar to the material and the forming method of the terminals <NUM> and the wiring <NUM> as described above.

For example, the protective portion <NUM> is provided on the insulation portion <NUM> and covers the detection units <NUM> and the wirings 82a to <NUM>. In this case, the terminals <NUM> are exposed from the protective portion <NUM>.

Even in the heater 1b, the substrate <NUM> having electrical conductivity functions as a wiring and a terminal which are electrically connected to the detection units <NUM> (the wirings 82b, 82d, 82f, and <NUM>). For example, as illustrated in <FIG>, the vicinity of an end of the substrate <NUM> on a side where the terminals <NUM> are provided functions as the terminal 81a that is electrically connected to the detection units <NUM> through the wirings 82b, 82d, 82f, and <NUM>.

As illustrated in <FIG>, in the longitudinal direction (X-direction) of the substrate <NUM>, when the terminals <NUM>, the terminals <NUM>, and the terminal 81a are provided in the vicinity of an end of the substrate <NUM> on the same side, the heater 1b and an external device can be electrically connected by one harness. According to this, simplification of routing of the harness, a reduction in a wiring space, easiness of wiring of the harness, shortening of wiring time, and the like can be accomplished.

In addition, since the substrate <NUM> having electrical conductivity functions as a wiring that is electrically connected to the detection units <NUM> (the wirings 82b, 82d, 82f, and <NUM>), it is not necessary to fold back the wirings 82b, 82d, 82f, and <NUM> to the terminal <NUM> side. Accordingly, the dimension of the substrate <NUM> in the lateral direction (Y-direction) can be reduced, and thus a reduction in size of the heater 1b can be accomplished.

In an exemplary embodiment, an image forming apparatus <NUM> including the heater <NUM> (1a or 1b) can be provided. Both the description relating to the above-described heater <NUM> and the modification examples of the heater <NUM> (for example, the heaters 1a and 1b) are applicable to the image forming apparatus <NUM>.

Note that, hereinafter, description will be given of a case where the image forming apparatus <NUM> is a copier as an example. However, the image forming apparatus <NUM> is not limited to the copier, and may be an apparatus provided with a heater configured to fix a toner. For example, the image forming apparatus <NUM> can be set as a printer, a rewritable card reader and writer, or the like.

<FIG> is a schematic view exemplifying the image forming apparatus <NUM> according to this embodiment.

<FIG> is a schematic view exemplifying a fixing unit <NUM>.

As illustrated in <FIG>, for example, the image forming apparatus <NUM> includes a frame <NUM>, an illumination unit <NUM>, an imaging element <NUM>, a photosensitive drum <NUM>, a charging unit <NUM>, a discharging unit <NUM>, a developing unit <NUM>, a cleaner <NUM>, an accommodation unit <NUM>, a conveying unit <NUM>, the fixing unit <NUM>, and a controller <NUM>.

The frame <NUM> has a box shape, and accommodates the illumination unit <NUM>, the imaging element <NUM>, the photosensitive drum <NUM>, the charging unit <NUM>, the developing unit <NUM>, the cleaner <NUM>, a part of the accommodation unit <NUM>, the conveying unit <NUM>, the fixing unit <NUM>, and the controller <NUM> at the inside.

A window <NUM> using a translucent material such as glass can be provided on an upper surface of the frame <NUM>. An original document <NUM> to be copied is placed on the window <NUM>. In addition, a movement unit configured to move a position of the original document <NUM> can be provided.

The illumination unit <NUM> is provided in the vicinity of the window <NUM>. For example, the illumination unit <NUM> includes a light source <NUM> such as a lamp and a reflecting mirror <NUM>.

The imaging element <NUM> is provided in the vicinity of the window <NUM>.

The photosensitive drum <NUM> is provided on a downward side of the illumination unit <NUM> and the imaging element <NUM>. The photosensitive drum <NUM> is rotatably provided. For example, a zinc oxide photosensitive layer or an organic semiconductor photosensitive layer is provided on a surface of the photosensitive drum <NUM>.

The charging unit <NUM>, the discharging unit <NUM>, the developing unit <NUM>, and the cleaner <NUM> are provided at the periphery of the photosensitive drum <NUM>.

For example, the accommodation unit <NUM> has a cassette <NUM> and a tray <NUM>. The cassette <NUM> detachably attached to one side portion of the frame <NUM>. The tray <NUM> is provided on a side portion of the frame <NUM> which is opposite to the side to which the cassette <NUM> is attached. Paper <NUM> (for example, white paper) before performing copying is accommodated in the cassette <NUM>. Paper <NUM> to which a copy image 511a is fixed is accommodated in the tray <NUM>.

The conveying unit <NUM> is provided on a downward side of the photosensitive drum <NUM>. The conveying unit <NUM> conveys the paper <NUM> between the cassette <NUM> and the tray <NUM>. For example, the conveying unit <NUM> includes a guide <NUM> that supports the conveyed paper <NUM> and conveying rollers <NUM> to <NUM> which convey the paper <NUM>. In addition, a motor configured to rotate the conveying rollers <NUM> to <NUM> can be provided in the conveying unit <NUM>.

The fixing unit <NUM> is provided downstream of the photosensitive drum <NUM> (tray <NUM> side).

As illustrated in <FIG>, for example, the fixing unit <NUM> includes the heater <NUM> (1a or 1b), a stay <NUM>, a film belt <NUM>, and a pressing roller <NUM>.

The heater <NUM> (1a or 1b) is attached to a paper <NUM> conveying line side in the stay <NUM>. The heater <NUM> (1a or 1b) can be embedded in the stay <NUM>. For example, a side of the heater <NUM> (1a or 1b) where the protective portion <NUM> is provided can be exposed from the stay <NUM>.

The film belt <NUM> covers the stay <NUM> provided with the heater <NUM> (1a or 1b). For example, the film belt <NUM> can be formed from a heat-resistant resin such as polyimide.

The pressing roller <NUM> is provided to face the stay <NUM>. For example, the pressing roller <NUM> includes a cored bar 203a, a drive shaft 203b, and an elastic portion 203c. The drive shaft 203b protrudes from an end of the cored bar 203a, and is connected to a drive device such as a motor. The elastic portion 203c is provided on an outer surface of the cored bar 203a. The elastic portion 203c is formed from a heat-resistant elastic material. For example, the elastic portion 203c can be formed from a silicone resin or the like.

The controller <NUM> is provided inside the frame <NUM>. For example, the controller <NUM> includes an operation unit such as a central processing unit (CPU), and a storage unit that stores a control program. The operation unit controls operations of respective elements provided in the image forming apparatus <NUM> on the basis of the control program stored in the storage unit. In addition, the controller <NUM> may include an operating unit configured to input copying conditions and the like by a user, a display unit configured to display an operation state, an abnormal display, or the like, and the like.

Note that, since a known technology is applicable for control of the respective elements provided in the image forming apparatus <NUM>, detailed description will be omitted.

Claim 1:
A heater (<NUM>), comprising:
a substrate (<NUM>) that has electrical conductivity and extends in a first direction;
a first insulation portion (<NUM>) that is provided on a first surface (10a) of the substrate (<NUM>), has an insulation property, and extends in the first direction;
at least one heat generation body (<NUM>) that is provided on the first insulation portion (<NUM>) and extends in the first direction;
a second insulation portion (<NUM>) that is provided on a second surface (10b) of the substrate (<NUM>) which is opposite to the first surface (10a), has an insulation property, and extends in the first direction;
at least one detection unit (<NUM>, <NUM>) provided on at least one of the first insulation portion (<NUM>) and the second insulation portion (<NUM>); and
a first wiring (<NUM>) which is provided on at least one of the first insulation portion (<NUM>) and the second insulation portion (<NUM>) and extends in the first direction, and in which one end is electrically connected to one terminal of the detection unit (<NUM>, <NUM>) and the other end is electrically connected to the substrate (<NUM>) having the electrical conductivity.