JP2011029088A - Ceramic heater, heating device, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To uniformize the temperature distribution in a ceramic heater in the longitudinal direction. <P>SOLUTION: A heating resistor 20 whose width and length is along the long side direction and the short side direction, respectively, of an elongated-plate-like ceramic substrate 11, and electrode 12, 13 for supplying power are formed. Separately-formed wiring patterns 141-143, 151-153 are connected to both ends of the heating resistor 20 on the ceramic substrate 11. A through-hole 181 formed in the electrode 12 is connected, via a connection pattern 16, to each of through-holes 182-184 formed at centers of the wiring patterns 141-143 in the longitudinal direction. A through-hole 191 formed in the electrode 13 is connected, via a connection pattern 17, to each of through-holes 192-194 formed at the centers of the wiring patterns 151-153 in the longitudinal direction. Portions of the heating resistor 20 across which the through-holes 182, 183 and 184 face the through-holes 192, 193 and 194, respectively, are set to generate larger amount of heat, to thereby uniformize the distribution of temperature all over the ceramic heater. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a thin ceramic heater that is used by being mounted on small devices such as information equipment, home appliances, and manufacturing equipment, and a heating device such as a printer, a copying machine, a facsimile, a rewritable card reader / writer, and the like mounted with the ceramic heater, The present invention relates to an image forming apparatus using the heating device.

  The conventional ceramic heater has both ends in the longitudinal direction of the heating resistor in order to make the heat generation of the heating resistor whose width in the longitudinal direction is long and the length in the short direction is uniform with respect to the longitudinal direction of the ceramic substrate. Are respectively connected to the wiring patterns. When power is supplied from the electrodes to the wiring pattern, the amount of heat generated in the longitudinal direction of the ceramic substrate can be made uniform by reducing the current gradient by connecting the wiring pattern and the electrode using a plurality of through holes. It is illustrated. (For example, Patent Document 1)

JP 2007-311135 A

  In the technique of Patent Document 1 described above, a temperature distribution gradient occurs due to a difference in resistance value due to a difference in distance from an electrode to which power is supplied to each through hole formed in the wiring pattern, and the entire heater is in the longitudinal direction. There was a problem that the temperature distribution was inclined.

  An object of the present invention is to provide a ceramic heater capable of achieving a uniform temperature distribution in the longitudinal direction, a heating device using the heater, and an image forming apparatus using the heating device.

  In order to solve the above-described problems, a ceramic heater according to the present invention is formed on a long, flat, heat-resistant, insulating ceramic substrate and the ceramic substrate, and the length of the short side of the ceramic substrate is long. A heating resistor having a width in the longitudinal direction, first and second wiring patterns formed along both longitudinal ends of the heating resistor and connected to both ends of the heating resistor, and one surface side on the ceramic substrate First and second electrodes to which power is supplied, first and second connection patterns respectively formed on opposite surfaces on which the heating resistors are formed, and the first electrode A through hole that connects the first wiring pattern via the first connection pattern and connects the second electrode and the second wiring pattern via the second connection pattern, respectively. The first wiring pattern is divided into a plurality in the longitudinal direction, each of the divided wiring patterns is connected to the connection pattern through a through hole, and the second wiring pattern is arranged in the longitudinal direction. The wiring pattern is divided into a plurality of wiring patterns, and each of the divided wiring patterns and the connection pattern are connected to each other through a through hole.

  A heating device according to the present invention includes a ceramic heater according to any one of claims 1 to 4, a pressure roller that is disposed so as to face the ceramic substrate and is rotatably supported so as to press-contact the ceramic substrate, And a fixing film that is provided between the ceramic substrate and the pressure roller and slides on the ceramic substrate as the pressure roller rotates.

  The image forming apparatus according to the present invention includes a forming unit that forms a predetermined image by attaching toner to an electrostatic latent image formed on a medium and transferring the toner to a sheet, and pressurizes the sheet on which the image is formed. 6. A heating apparatus according to claim 5, wherein the toner is fixed by passing through the fixing film with a roller while being pressed against the heater.

  According to the present invention, it is possible to make the temperature distribution in the longitudinal direction of the ceramic heater uniform.

BRIEF DESCRIPTION OF THE DRAWINGS (a) is a front view for demonstrating 1st Embodiment regarding the ceramic heater of this invention, (b) is a rear view. It is the Ia-Ib sectional view taken on the line of FIG. It is explanatory drawing typically shown in order to demonstrate the effect of 1st Embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS (a) is a front view for demonstrating 2nd Embodiment regarding the ceramic heater of this invention, (b) is a rear view. It is the IIa-IIb sectional view taken on the line of FIG. It is the IIc-IId sectional view taken on the line of FIG. It is explanatory drawing typically shown in order to demonstrate the effect of 2nd Embodiment of this invention. (A) is a front view, (b) is a rear view for demonstrating 3rd Embodiment regarding the ceramic heater of this invention. It is the IIIa-IIIb sectional view taken on the line of FIG. It is the IIIc-IIId sectional view taken on the line of FIG. It is the IIIe-IIIf sectional view taken on the line of FIG. It is explanatory drawing typically shown in order to demonstrate the effect of 3rd Embodiment of this invention. It is explanatory drawing for demonstrating one Embodiment regarding the heating apparatus of this invention. It is explanatory drawing for demonstrating one Embodiment regarding the image forming apparatus of this invention.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

  1 and 2 are diagrams for explaining a first embodiment of the ceramic heater according to the present invention, in which FIG. 1 (a) is a front view, FIG. 1 (b) is a rear view, and FIG. It is sectional drawing of Ib line.

  In the following embodiments, the same components as those in this embodiment are denoted by the same reference numerals, and the description thereof is omitted.

First, in FIG. 1A, 11 is a heat-resistant and electrically insulating material having a thickness of about 0.5 mm to 1.0 mm, and has high thermal conductivity such as alumina (Al ₂ O ₃ ), aluminum nitride (AlN). ) Or the like, and a ceramic substrate having a flat strip shape made of a highly rigid ceramic. Reference numerals 12 and 13 formed on one end side in the longitudinal direction of the ceramic substrate 11 are power supply electrodes made of a good conductor film mainly composed of silver or the like.

  Reference numerals 141 to 143 denote wiring patterns that are arranged in a non-contact state along one side in the longitudinal direction of the ceramic substrate 11 and are formed of a material having a silver (Ag) content of 90 wt% or more. 151 to 153 are wiring patterns that are arranged in a non-contact state in parallel with the wiring patterns 141 to 143 on the other side in the longitudinal direction of the ceramic substrate 11 and are formed of a material having a silver (Ag) content of 90 wt% or more. is there. The opposing wiring patterns 141 to 143 and the wiring patterns 151 to 153 have the same shape.

  The electrodes 12 and 13 and the wiring patterns 141 to 143 and 151 to 153 are formed on the surface on one side in the longitudinal direction of the ceramic substrate 11 in different states. The electrodes 12 and 13 and the wiring patterns 141 to 143 and 151 to 152 can be formed in a state where they are fixed on the ceramic substrate 11 by applying a conductive paste on the ceramic substrate 11 and firing it.

  As shown in FIG. 1B, a connection pattern 16 for connecting the electrode 12 and the wiring patterns 141 to 143 is formed at a position facing the longitudinal direction of the wiring patterns 141 to 143 and the ceramic substrate 11. Similarly, a connection pattern 17 for connecting the electrode 13 and the wiring patterns 151 to 153 is formed in the longitudinal direction of the wiring patterns 151 to 153 and in the vicinity of the counter electrode 12 across the ceramic substrate 11.

  As shown in FIG. 2, the electrode 12 and the connection pattern 16 are electrically connected via the through hole 181. The electrode 13 and the connection pattern 17 are electrically connected through the through hole 191.

  A through hole 182 is formed in the middle portion of the wiring pattern 141 in the longitudinal direction, a through hole 183 is formed in the middle portion of the wiring pattern 142 in the longitudinal direction, and a through hole 184 is formed in the middle portion of the wiring pattern 143 in the longitudinal direction. The

  The opposite side of the through hole 182 where the wiring pattern 14 is formed is integrally connected to the connection pattern 16. The opposite side of the through hole 183 from the surface on which the wiring pattern 14 is formed is connected integrally with the connection pattern 16. The opposite side of the through hole 184 from the surface on which the wiring pattern 14 is formed is integrally connected to the connection pattern 16.

  A through hole 192 is formed in the middle portion of the wiring pattern 151 in the longitudinal direction, a through hole 192 is formed in the middle portion of the wiring pattern 152 in the longitudinal direction, and a through hole 193 is formed in the middle portion of the wiring pattern 153 in the longitudinal direction. To do.

  The opposite side of the through hole 192 from the surface on which the wiring pattern 151 is formed is connected integrally with the connection pattern 17. The opposite side of the through hole 193 from the surface on which the wiring pattern 152 is formed is connected integrally with the connection pattern 17. The opposite side of the through hole 194 from the surface on which the wiring pattern 153 is formed is integrally connected to the connection pattern 17.

  The through holes 182 and 192, the through holes 183 and 193, and the through holes 184 and 194 are formed on the same line as the direction in which the ceramic substrate 11 is passed.

20 is a resistor paste such as ruthenium oxide (RuO ₂ ) having a relatively high resistance value formed in parallel along the longitudinal direction of the ceramic substrate 11 between the wiring patterns 141 to 143 and the wiring patterns 151 to 153. After the screen printing, it is a wide heating resistor having a film thickness of about 10 μm that is fired at a high temperature and has a predetermined resistance value.

  The wiring patterns 141 to 143 and the heating resistor 20, the wiring patterns 151 to 153, and the heating resistor 20 are partly formed in multiple layers as shown in FIG. 2. In this case, the multilayer portion has a relationship in which the heating resistor 20 is arranged on the upper side with respect to the wiring patterns 141 to 143 and the wiring patterns 151 to 153. This relationship may be reversed.

  21 is formed so as to cover the wiring patterns 141 to 143, 151 to 153 and the heating resistor 20, and has a glass layer thickness of about 20 μm to 100 μm and a thermal conductivity such as alumina of 2 W / m · K or more. It is an overcoat layer such as glass whose slidability is improved by adding 25 wt% to 35 wt% of an inorganic oxide filler having excellent properties. The overcoat layer 21 mechanically, chemically and electrically protects the wiring patterns 141 to 143 and 151 to 153 and the heating resistor 20. The sheet to be heated is slid on the overcoat layer 21 and conveyed in the short direction of the ceramic substrate 11 while being heated.

  Here, the electric power supplied from the electrode 12 to the connection pattern 16 via the through hole 181 is supplied to one of the heating resistors 20 via the through hole 182 and the wiring pattern 141 via the through hole 183 and the wiring pattern 142. One of the heating resistors 20 is supplied to one of the heating resistors 20 through the through hole 183 and the wiring pattern 143, respectively.

  The electric power supplied from the electrode 13 to the connection pattern 17 through the through hole 191 is supplied to one of the heating resistors 20 through the through hole 192 and the wiring pattern 151, and the heating resistor through the through hole 193 and the wiring pattern 152. One of the heating resistors 20 is supplied to one of the heating resistors 20 via the through hole 193 and the wiring pattern 153.

  As a result, when power is supplied to both ends of the heating resistor 20 whose length in the short direction of the ceramic substrate 11 is energized, the heating resistor 20 starts to generate heat.

  The electric power supplied from the electrodes 12 and 13 is applied to the heating resistor 20 between the wiring patterns 141 to 143 and the wiring patterns 151 to 153 via the through holes 182 to 184 via the through holes 182 to 184. .

  At this time, in the portion of the heating resistor 20 indicated by broken line frames a to d indicated by arrows in FIG. 1A, the through hole 182 and the through hole 192, the through hole 183 and the through hole 193, the through hole 183 and the through hole 193, Since the distance between the through hole 184 and the through hole 194 is the shortest, the resistance value is small and the current easily flows, so that the amount of heat generation increases.

  Here, the effect of the first embodiment of the present invention will be described with reference to the schematic explanatory diagram of FIG.

  As shown in FIG. 5, in the conventional ceramic heater, the temperature distribution is inclined due to the difference in the length of the connection pattern between the side close to the electrode and the side far from the electrode, in other words, the difference in resistance value. In the ceramic heater according to the present invention, the amount of heat generated is high in the shortest portion of the through-holes in the opposing positional relationship, which corresponds to the regions of the broken line frames a to c in FIG. For this reason, like the temperature distribution shown in FIG. 5, the temperature of the part corresponded to broken-line frame ac is high. The broken dashed frames a to c are present at three locations in the longitudinal direction of the ceramic substrate, and the entire heating resistor 20 contributes to uniform temperature.

  In this embodiment, the temperature distribution in the longitudinal direction of the ceramic substrate is contributed to uniform temperature distribution, and the means for equalizing the temperature distribution is applied to the side opposite to the paper surface. It becomes possible to suppress the influence.

  4 to 6 are diagrams for explaining a second embodiment of the ceramic heater according to the present invention. FIG. 4 (a) is a front view, FIG. 4 (b) is a rear view, and FIG. FIG. 6 is a sectional view taken along line IIb-IId in FIG.

  In this embodiment, the length of the wiring pattern 142 is longer than that of the wiring patterns 141 and 143, and the length of the wiring patterns 151 and 153 is longer than that of the wiring pattern 152. For this reason, the through holes 182, 192, the through holes 183, 193, and the through holes 184, 194, which are formed in the intermediate portion in the longitudinal direction of the wiring patterns 141 to 143, are respectively on the same line with respect to the sheet passing direction of the ceramic substrate 11. It is out of position, and the positional relationship is slightly oblique.

  Here, the effect of the second embodiment of the present invention will be described with reference to a schematic diagram of FIG.

  That is, since the width of the portion where the temperature is increased is wider than that of the first embodiment in the longitudinal direction of the ceramic substrate 11, the portion where the temperature distribution is increased is slightly as shown by the solid line in FIG. It becomes gentle and can be made more uniform as a whole.

  8 to 11 are views for explaining a third embodiment of the ceramic heater according to the present invention. FIG. 8 (a) is a front view, FIG. 8 (b) is a rear view, and FIG. 9 is IIIa- in FIG. FIG. 10 is a sectional view taken along line IIIb, FIG. 10 is a sectional view taken along line IIIc-IIId in FIG. 8, and FIG. 11 is a sectional view taken along line IIIe-IIIf in FIG.

  In this embodiment, the wiring patterns 141 to 143 divided into three along one side in the longitudinal direction of the ceramic substrate 11 are divided into two in parallel with the wiring patterns 141 to 143 on the other side in the longitudinal direction of the ceramic substrate 11. Wiring patterns 154 and 155 are formed, respectively. The heating resistor 20 is connected between the wiring patterns 141 to 143 and the wiring patterns 154 and 155.

  For example, the wiring patterns 141 to 143 have the same length, and the entire length is just fit in the width direction of the heating resistor 20. Similarly, the wiring patterns 154 and 155 have the same length, for example, and the entire length just fits in the width direction of the heating resistor 20.

  The through hole 182 is closer to the electrode 12 in the longitudinal direction of the wiring pattern 141, the through hole 183 is in the middle of the longitudinal direction of the wiring pattern 142, and the through hole 184 is far from the electrode 12 in the longitudinal direction of the wiring pattern 143. Form each one.

  The through hole 195 formed in the wiring pattern 154 is located at a position facing the gap 81 between the wiring patterns 141 and 142, and the through hole 196 formed at the wiring pattern 155 is located at the position facing the gap 82 between the wiring patterns 142 and 143. To form each.

  The through holes 182 to 183 are electrically connected to the connection pattern 16, and the through holes 195 and 196 are electrically connected to the connection pattern 17, respectively.

  The through holes 182 to 184 and the through holes 195 and 196 are arranged in a staggered manner in the longitudinal direction of the ceramic substrate 11 as shown in FIG.

  Here, the electric power supplied from the electrode 12 to the connection pattern 16 via the through hole 181 is supplied to one of the heating resistors 20 via the through hole 182 and the wiring pattern 141 via the through hole 183 and the wiring pattern 142. One of the heating resistors 20 is supplied to one of the heating resistors 20 through the through hole 183 and the wiring pattern 142, respectively.

  The electric power supplied from the electrode 13 to the connection pattern 17 through the through hole 191 is supplied to the other side of the heating resistor 20 through the through hole 195 and the wiring pattern 154, and to the heating resistor through the through hole 196 and the wiring pattern 155. Each of the other 20 is supplied.

  As a result, when power is supplied to both ends of the heating resistor 20 whose length in the short direction of the ceramic substrate 11 is energized, the heating resistor 20 starts to generate heat.

  The electric power supplied from the electrodes 12 and 13 is applied to the heating resistor 20 between the wiring patterns 141 to 143 and the wiring patterns 154 and 155 via the through holes 182 to 184 and the through holes 195 and 196. .

  At this time, in the portion of the heating resistor 20 indicated by broken line frames a, b1, b2, and c indicated by arrows in FIG. 8A, the through hole 182, the through hole 195, the through hole 183, the through hole 195, and the through hole 18 are provided. A current easily flows between the through hole 196 and the through hole 184 and the through hole 196 as compared with other portions, and the amount of heat generation increases.

  The more oblique heat generation amount portion covers the entire area of the heating resistor 20 in a state where the longitudinal direction of the ceramic substrate 11 is connected, and the heat generation amount portion 20 covers the entire area of the heating resistor 20 in the longitudinal direction. A uniform heat generation distribution can be obtained.

  As described above, the divided wiring pattern lengths are different between the upstream and downstream of the heater, and the through holes of the conductors facing the divided portions of the conductors upstream and downstream of the heater in the sheet passing portion are in the same position in the longitudinal direction. A small smooth heat generation distribution can be obtained.

  Here, the effect of the present invention will be described with reference to the explanatory diagram of FIG. 12 schematically shown.

  As shown in FIG. 12, in the conventional ceramic heater, the temperature distribution is inclined due to the difference in the length of the connection pattern between the side close to the electrode and the side far from the electrode, in other words, the difference in resistance value. Since the ceramic heater in the case of the present invention can increase the temperature in the regions of the broken line frames a, b1, b2, c of FIG. 8A, the broken line frames a, b1, b2 as shown in the temperature distribution of FIG. , C becomes high, and the temperature of the entire heating resistor 20 can be made uniform.

  Further, since the through holes 182 and 184 are located in the vicinity of both sides in the width direction of the heating resistor 20, the temperature in this portion increases and a wider temperature distribution is obtained.

  In this embodiment, the temperature distribution in a wider range in the longitudinal direction of the ceramic substrate can be made uniform, and the means for making the temperature distribution uniform is provided on the side opposite to the paper surface. It is possible to suppress the influence of the accompanying change in temperature distribution.

  FIG. 13 is a cross-sectional view when a heater unit in which the ceramic heater 100 described above is attached to a heater support is mounted on the heating device 200 for explaining an embodiment relating to the heating device of the present invention. Reference numeral 100 in the figure denotes the ceramic heater described in FIGS. 1 and 2, and the same parts are denoted by the same reference numerals, and the description thereof is omitted.

  In FIG. 13, reference numeral 201 denotes a cylindrical fixing film in which a heat-resistant film such as a polyimide resin is rolled to be circulated. The fixing film 201 is fixed to the bottom of the support 202, the ceramic heater 100 is fixed, electric power is supplied to the ceramic heater 100, and the fixing film 201 is moved to the overcoat layer 21 formed on the heated ceramic heater 100 while being pressed and heated.

  Reference numeral 203 denotes a pressure roller, which is a heat-resistant elastic material, for example, a silicone rubber layer 204 fitted on the surface thereof. The ceramic heater 100 faces the rotation shaft 205 of the pressure roller 203 and the fixing film 201. And mounted in a base (not shown). The pressure roller 203 is brought into pressure contact with the fixing film 201 to form a nip portion N formed by the heating resistor 20 and the pressure roller 203, and each is rotated in the direction of the arrow during operation.

  At this time, the toner image To1 is first heated and melted by the ceramic heater 100 via the fixing film 201 between the surface of the fixing film 201 disposed on the overcoat layer 21 and the silicone rubber layer 204, and at least the surface portion thereof is It greatly exceeds the melting point and completely softens and melts. Thereafter, on the paper discharge side of the pressure roller 203, the copy paper P is separated from the ceramic heater 100, the toner image To2 is naturally radiated to be cooled and solidified again, and the fixing film 201 is also separated from the copy paper P.

  In this embodiment, the temperature gradient in the longitudinal direction of the ceramic heater is suppressed, and the temperature distribution of the entire heat generating portion is made uniform, so that the heating unevenness of the heated object heated by the ceramic heater can be reduced. It becomes possible.

  Next, with reference to FIG. 14, an image forming apparatus according to the present invention will be described in the case of a copying machine equipped with the heating device 200 according to the present invention. In the figure, the part of the heating device 200 is the same as that described with reference to FIG. 13, and the same reference numerals are given to the same parts, and the description thereof is omitted.

  In FIG. 14, reference numeral 301 denotes a casing of the copying machine 300, and 302 an original placement table made of a transparent member such as glass provided on the upper surface of the casing 301, which scans the original P <b> 1 by reciprocating in the arrow Z direction.

  An illuminating device 302 including a light irradiation lamp and a reflecting mirror is provided in the upper direction in the housing 301, and a reflected light source from the document P1 irradiated by the illuminating device 302 is a short focus small diameter imaging element. A slit exposure is performed on the photosensitive drum 304 by the array 303. The photosensitive drum 304 rotates in the direction of the arrow.

  Reference numeral 305 denotes a charger that uniformly charges, for example, a photosensitive drum 304 coated with a zinc oxide photosensitive layer or an organic semiconductor photosensitive layer. An electrostatic image subjected to image exposure by the imaging element array 303 is formed on the photosensitive drum 304 charged by the charger 305. This electrostatic image is visualized using toner made of a resin that softens and melts when heated by the developing device 306.

  The copy paper P stored in the cassette 307 is rotated by a pair of conveying rollers 309 that are rotated in pressure contact with each other in synchronization with the feeding roller 308 and the image on the photosensitive drum 304. Sent to the top. The toner image formed on the photosensitive drum 304 is transferred onto the copy paper P by the transfer discharger 310.

  Thereafter, the paper P that is separated from the photosensitive drum 304 is guided to the heating device 200 by the conveyance guide 311 and subjected to a heat fixing process, and then is discharged into the tray 312. After the toner image is transferred, residual toner on the photosensitive drum 304 is removed using a cleaner 313.

  The heating device 200 has an effective length according to the width (length) of the maximum size paper that can be copied by the copying machine 300 in the direction orthogonal to the moving direction of the copy paper P, that is, the width (length) of the maximum size paper. A ceramic heater 100 having a long heating resistor is provided in a state of being pressed by a silicone rubber layer 204 attached to the outer periphery of the pressure roller 203.

  The unfixed toner image T1 on the paper P sent between the ceramic heater 100 and the pressure roller 203 is melted by the heat of the heat generating resistor 20 and has characters, alphanumeric characters and symbols on the copy paper P surface. A copy image such as a drawing is displayed.

  In this embodiment, by using a heating device provided with a ceramic heater in which the temperature distribution of the portion where the heating resistor is formed is made uniform, heating unevenness can be suppressed, and thus fixing failure can be suppressed. It becomes possible.

  Ceramic heaters are used for fixing image forming devices such as copiers, but are not limited to this, and are installed in household electrical products, precision instruments for business use and experiments, and chemical reaction equipment. It can also be used as a heat source for heating and heat insulation.

DESCRIPTION OF SYMBOLS 11 Ceramic substrate 12, 13 Electrode 141-143, 151-155 Wiring pattern 16,17 Connection pattern 181-184,191-196 Through hole 20 Heating resistor 21 Overcoat layer 100 Ceramic heater 200 Heating device 201 Fixing film 203 Pressurization Roller 300 copier

Claims (6)

A long, flat, heat-resistant, insulating ceramic substrate;
A heating resistor formed on the ceramic substrate, the short direction of the ceramic substrate being length and the long direction being width;
First and second wiring patterns formed along both longitudinal ends of the heating resistor and connected to both ends of the heating resistor;
A first electrode and a second electrode which are respectively formed on one side of the ceramic substrate and supplied with power;
First and second connection patterns respectively formed on opposite surfaces on which the heating resistors are formed;
Through-through connecting the first electrode and the first wiring pattern via the first connection pattern, respectively, and connecting the second electrode and the second wiring pattern via the second connection pattern, respectively. A hall,
The first wiring pattern is divided into a plurality in the longitudinal direction, each of the divided wiring patterns is connected to the connection pattern through a through hole, and the second wiring pattern is arranged in the longitudinal direction. A ceramic heater, which is divided into a plurality of parts and each of the divided wiring patterns and the connection pattern are connected to each other through a through hole.   The first and second wiring patterns have the same number of divisions, the lengths of the positions facing each other through the heating resistor are the same, and the connection locations by the through holes with the connection pattern are in the longitudinal direction. The ceramic heater according to claim 1, wherein the ceramic heater is in an intermediate position.   The first and second wiring patterns have the same number of divisions, are different in length at positions facing each other through the heating resistor, and connect the connection pattern by the through hole with the connection pattern in the longitudinal direction. The ceramic heater according to claim 1, wherein the ceramic heater is in an intermediate position.   In the first and second wiring patterns, the number of divisions is different between the upstream side and the downstream side through which the heated body passes, and the positions of the through holes at both ends on the side where the number of divisions is large are formed on the side far from the center. 2. The ceramic heater according to claim 1, wherein the through hole on the side having the smaller number of divisions is formed at a position facing the gap of each wiring pattern on the side having the larger number of divisions. The ceramic heater according to any one of claims 1 to 4,
A pressure roller disposed opposite to the ceramic substrate and rotatably supported so as to press-contact the ceramic substrate;
A heating apparatus comprising: a fixing film provided between the ceramic substrate and the pressure roller and sliding on the ceramic substrate as the pressure roller rotates. Forming means for attaching a toner to an electrostatic latent image formed on a medium and transferring the toner to a sheet to form a predetermined image;
6. A heating apparatus according to claim 5, wherein the toner is fixed by passing a sheet on which an image is formed while being pressed against the heater through a fixing film by a pressure roller. Image forming apparatus.

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