JP2007035505A - Heater, heating device, image processing device - Google Patents

Abstract

A uniform heat generating surface wide in the width direction of an insulating substrate to which a heat generating resistor is fixed is obtained.
Heat generating resistors (12, 13) made of silver / palladium alloy are fixed along the longitudinal direction of a long flat insulating substrate (11) made of alumina or the like. Electric power is supplied to the electrodes 14 and 15 made of silver or the like, which does not easily generate a large heat generation phenomenon even when the insulating substrate 11 is energized. One end of the heating resistor 12 and the other end of the heating resistor 12 are connected to the connection conductor 16 through the connection conductor 141. One end of the heating resistor 13 and the other end of the heating resistor 13 are connected to the connection conductor 16 via the connection conductor 151. Thermal diffusion bodies 17 and 18 such as aluminum are fixed on the insulating substrate 11 between the heating resistors 12 and 13. The heating resistors 12 and 13, the connection conductor 16, and the heat diffusion bodies 17 and 18 are protected by a glass protective layer 19. The thermal diffusers 17 and 18 make uniform the heat generated from the heating resistors 12 and 13 on the protective layer 19.
[Selection] Figure 1

Description

  The present invention relates to a thin heater used in small equipment such as information equipment, home appliances, and manufacturing equipment, a heating device such as a printer, a copying machine, and a facsimile machine equipped with the heater, and an image using the heating device. The present invention relates to a processing apparatus.

In the conventional heater, a heating resistor is formed in a long and narrow shape along the longitudinal direction at a substantially central portion in the short width direction on the substrate surface, and electrodes for power feeding are arranged at both ends via conductors. The heating resistor and the conductor are covered and protected by a protective layer such as glass. (For example, Patent Document 1)
In addition, the heating resistors are configured to occupy a large area with respect to the substrate width by parallel connection or thinning. (For example, Patent Document 2)
Japanese Patent Laid-Open No. 10-221986 JP 2004-6299 A

  In the technique of the above-mentioned Patent Document 1, the heat generation width becomes narrower because the heating resistor is only at the center of the substrate width with respect to the substrate width. The technique of Patent Document 2 uses a large amount of heat generating material made of a relatively expensive material such as palladium, although the heat generation width can be widened. Nevertheless, since the insulating protective layer formed of glass or the like has a low thermal conductivity, there is a problem that the surface temperature of the protective layer causes a temperature difference between the portion where the heating element is located below and the portion where the heating element is not present.

  An object of the present invention is to provide a heater capable of obtaining a wide and uniform heat generating surface regardless of the wiring of the heat generating resistor, a heating device using the heater, and an image forming apparatus using the heating device.

  In order to solve the above-described problems, the heater of the present invention includes a long flat insulating substrate formed of a heat-resistant and insulating material, a heating resistor formed in the longitudinal direction of the insulating substrate, and the insulating An electrode for supplying power to the heating resistor formed on the substrate, a thermal diffuser for diffusing heat generated from the heating resistor formed on the insulating substrate, and at least the heating resistor And a protective layer covering the conductor and the heat diffusion body.

  Also, a heat-resistant and long flat insulating substrate, a heating resistor formed in a thick film on one surface of the insulating substrate, a conductor formed at both ends of the heating resistor, and the heating resistor of the conductor An electrode formed on the other side of the body to which power is supplied, an insulating layer formed so as to cover the heating resistor and the conductor, and generated in the heating resistor formed in or on the insulating layer And a thermal diffuser for diffusing the generated heat.

  According to the present invention, it is possible to obtain a uniform and wide heating surface in the width direction while suppressing the wiring relationship of the heating resistor.

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

  FIG. 1 is a front view for explaining an embodiment of the heater of the present invention, and FIG. 2 is an enlarged sectional view taken along line a-a ′ of FIG. 1.

In FIG. 1, 11 is a highly rigid and heat-resistant insulating substrate such as alumina (Al ₂ O ₃ ) or aluminum nitride (AlN), and 12 and 13 are conductive in parallel with the longitudinal direction of the insulating substrate 11. It is a heating resistor formed by thick film printing using a resistor paste composed of silver / palladium (Ag / Pd) or the like, and then firing at about 850 ° C. Reference numerals 14 and 15 denote conductors made of silver (Ag), silver / platinum (Ag / Pt), silver / palladium (Ag / Pd), etc., on the insulating substrate 11 that do not easily generate a large heat generation phenomenon even when energized. The electrode is supplied with electric power formed by thick film printing using a paste and then firing. A part of the electrode 14 is electrically connected to one end of the heating resistor 12 through a connection conductor 141 in a multilayer state. A part of the electrode 15 is electrically connected to one end of the heating resistor 13 through a connection conductor 151 in a multilayer state. No. 16 is formed by thick film printing using the same conductive paste as the electrodes 14 and 15, which are unlikely to generate a large heat generation phenomenon even when the insulating substrate 11 is energized by multilayering the other end and part of each of the heating resistors 12 and 13. A connecting conductor formed and electrically connected to the heating resistors 12 and 13.

  On the insulating substrate 11 positioned outside the heat generating resistors 12 and 13, the heat diffusion bodies 17 and 18 are fixed along the heat generating resistors 12 and 13. The thermal conductivity of the thermal diffusers 17 and 18 is made of a material having a thermal conductivity of 120 W / m · K or more, which is at least three times the thermal conductivity of 20 W / m · K when the insulating substrate 11 is an alumina substrate. . As a material of such a heat diffusion body, any metal or metal compound such as aluminum, silver, tungsten, copper, magnesium, etc. can be considered.

Reference numeral 19 denotes a protective layer using a thick film printing method formed by applying and baking a glass paste for covering and protecting the heating resistors 12 and 13, the connection conductor 16, and the thermal diffusion bodies 17 and 18. The protective layer 19 is made by adding lead-free amorphous SiO, borosilicate glass mainly containing B ₂ O ₃ and alumina having higher thermal conductivity than glass.

  FIG. 3 shows the result of measuring the temperature distribution in the width direction of the insulating substrate 11 by supplying power to the electrodes 14 and 15 to cause the heating resistors 12 and 13 to generate heat.

  As is apparent from the temperature distribution indicated by the solid line in FIG. 3, the temperature in the vicinity of the heating resistor 12 is slightly higher than the other parts, but the conventional temperature distribution without the thermal diffusion bodies 17 and 18 indicated by the broken line in the figure is obtained. In comparison, a substantially uniform distribution state can be obtained as a whole. This means that a substantially uniform temperature distribution can be obtained by the diffusing action of the heat diffusing bodies 17 and 18 regardless of the distance from the heating resistor in the width direction of the insulating substrate 11. The desired temperature can be obtained in a wide range.

  In this embodiment, a heater having a uniform and wide heat generation width can be realized by a simple configuration in which the heat diffusion resistors 17 and 18 such as aluminum are arranged on the heat generating resistors 12 and 13.

  4 and 6 show first and second modifications of the above-described embodiment. FIG. 5 is a cross-sectional view taken along line bb ′ of FIG. 4, and FIG. 7 is a cross-sectional view taken along line cc ′ of FIG. The same components as those in FIGS. 1 and 2 are denoted by the same reference numerals for explanation.

  4 and 5 is a wiring pattern formed by using the heating resistor 12 between the electrode 14 and the connection conductor 16 and using the same conductive paste as the electrode 16 between the electrode 15 and the connection conductor 16. 41 are fixed on the insulating substrate 11, respectively. On the insulating substrate 11 located outside the heating resistor 12 and the wiring pattern 41, heat diffusion bodies 17 and 18 such as aluminum are fixed along the heating resistor 12 and the wiring pattern 41.

  In the second modification of FIGS. 6 and 7, a heat diffusion body 61 such as aluminum is formed along the middle of the heating resistors 12 and 13.

  Even in the first and second modifications of the heat generating resistor, the temperature distribution in the width direction of the insulating substrate 11 is almost uniform and wide as shown in FIG. It becomes possible to do.

  8 and 9 are diagrams for explaining another embodiment of the heater of the present invention. FIG. 8 is a front view, FIG. 9 is a sectional view taken along the line dd ′ of FIG. 8, and is the same as FIG. Components will be described with the same reference numerals.

  In this embodiment, instead of the heat spreaders 17 and 18 in FIG. 4, a heat diffuser 81 made of any metal or metal compound such as aluminum, silver, tungsten, copper, magnesium, etc. is formed on at least the protective layer 19. Is.

  FIG. 10 shows the result of measuring the temperature distribution in the width direction of the insulating substrate 11 by supplying power to the electrodes 14 and 15 to cause the heating resistor 12 to generate heat.

  As is clear from the temperature distribution indicated by the solid line in FIG. 10, a uniform temperature distribution state can be obtained over the entire width of the thermal diffusion body 81. This means that a uniform temperature distribution can be obtained regardless of the distance from the heating resistor in the width direction of the insulating substrate 11, and a constant temperature can be obtained over a wide range with a simple configuration.

  In this embodiment, a heater having a uniform and wide heat generation width can be realized by a simple configuration in which a heat diffusion plate 81 such as aluminum is disposed on the protective layer 19.

  11 and 12 are diagrams for explaining a modification of another embodiment of the heater of the present invention, FIG. 11 is a front view, and FIG. 12 is an e-e ′ sectional view of FIG. 11. The same components as those in FIGS. 1 and 2 are denoted by the same reference numerals.

  In this embodiment, instead of the heat spreaders 17 and 18 in FIG. 1, a heat diffuser 81 made of any metal or metal compound such as aluminum, silver, tungsten, copper, magnesium, etc. is formed on at least the protective layer 19. Further, a glass protective layer 111 having a surface roughness Rz of 2 μm or less is formed on the upper surface of the thermal diffuser 81.

  In the case of this embodiment, the heat diffusion member 81 makes the heat distribution in the width direction of the insulating substrate 11 shown in FIG. 10 uniform, and the surface roughness of the glass protective layer 111 is fine. Can be made smooth.

  Further, the protective layer formed on the upper surface of the thermal diffuser 81 is not limited to glass, and a heat resistant engineering plastic protective layer such as polyimide or polyamideimide may be formed. In the case of this heat-resistant engineering plastic protective layer, the fixing film may be a metal because it is softer than the glass protective layer.

  Next, with reference to FIG. 13, an embodiment of the heating device of the present invention when the above-described heater is mounted on the heating device 200 for fixing will be described. The heater 100 in the figure is the same as that in FIGS. 1 and 2, and the same portions are denoted by the same reference numerals and description thereof is omitted.

  In FIG. 13, reference numeral 201 denotes a pressure roller that is rotated by a rotating shaft 202, and a heat-resistant elastic material such as a silicone rubber layer 203 is fitted on the surface thereof. The heater 100 is juxtaposed with the rotating shaft 202 of the pressure roller 201 and attached to a base (not shown).

  Around the heater 100, an endless roll-shaped fixing film 204 made of a heat-resistant sheet such as a polyimide resin is circulated so as to be circulated, and protection is provided directly above the insulating substrate 11 via the heating resistors 12 and 13. The surface of the layer 19 is in elastic contact with the silicone rubber layer 203 of the pressure roller 201 through the fixing film 204.

  In the heating device 200, the heater 100 is energized through a connector (not shown) in which a phosphor bronze plate or the like in contact with the electrodes 14, 15 is given a silver plated elasticity. By this energization, the toner image T1 is first transferred between the surface of the fixing film 204 provided on the protective layer 19 of the heat generating resistors 12 and 13 and the silicone rubber layer 203 by the heater 100 via the fixing film 204. When heated and melted, at least the surface part greatly exceeds the melting point and is completely softened and melted. Thereafter, on the paper discharge side of the pressure roller 201, the copy paper P is separated from the heater 100, the toner image T2 is naturally radiated and cooled and solidified again, and the fixing film 204 is also separated from the copy paper P.

  As described above, the toner image T1 is once completely softened and melted and then cooled again on the paper discharge side of the pressure roller 201, so that the condensing force of the toner image T2 is very large.

  In this embodiment, even if an abnormal temperature rise occurs due to the temperature control of the heater 100, the time until the heater 100 is damaged or the insulating substrate 11 is cracked can be given by the action of the slit 18. During this time, it is possible to improve the safety of the heating device 200 by preventing the thick film printing heater from being damaged until another safety element such as a temperature fuse on the heating device 200 side functions.

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

  In FIG. 14, 301 is a casing of the copying machine 300, 302 is a document placing table made of a transparent member such as glass provided on the upper surface of the casing 301, and scans the document P1 by reciprocating in the arrow Y 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 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. The pressure roller 201 of the heater 100 is provided by extending the long heating resistors 12 and 13.

  Then, the unfixed toner image T1 on the paper P sent between the heater 100 and the pressure roller 201 is melted by receiving heat from the heating resistors 12 and 13, and characters, alphanumeric characters, Copy images such as symbols and drawings are displayed.

  In this embodiment, it is possible to realize the copying machine 300 using the heating device 200 by the good heater 100 that is improved in safety against abnormal heat generation.

  The present invention is not limited to the embodiment described above. For example, the protective layer material cannot be specified because it needs to be changed depending on the material of the opposite fixing film and other conditions, but when the fixing film is resin, the protective layer is glass or the fixing film is metal, and the protective layer is made of resin. It is desirable to combine them. As this resin, polyamide (PA), polyacetal (POM), polytetrafluoroethylene (PTFE), polyphenylene sulfide, elastomers, polyolefins, fluorine, etc., which are generally considered to be excellent in slidability, are used. Conceivable. Basically, any of them may be used, but imides such as PI (polyimide) and PAI (polyamideimide), which are heat-resistant and elastic, are preferable, but if the hardness is too low, the resin coating will be scraped off. Therefore, for example, a hardness of 3H or more is necessary.

  The thermistor 23 in the embodiment described with reference to FIGS. 1 to 3 is on the insulating substrate 11 opposite to the heating resistors 12 and 13, but may be disposed on the protective layer 19 as shown in FIG. 6. Good. In this case, the position where the thermistor 23 is attached is a position away from the electrodes 14 and 15, and as described in other embodiments, the portion where the thermistor 23 is disposed is filled to suppress the influence of temperature detection by the slit 18. May be.

  Furthermore, the fixing heater is used for fixing an image forming apparatus such as a copying machine, but is not limited to this, and is not limited to a household electrical product, a precision device for business use or experiment, a device for chemical reaction, etc. It can also be used as a heat source for heating and heat retention.

  Next, in addition to the technical idea described in the claims, the technical idea grasped by the above-described embodiment will be described below together with the effects thereof.

(1) A heat-resistant and long flat insulating substrate, a heating resistor formed on one surface of the insulating substrate, a conductor formed on both ends of the heating resistor, and the heat generation of the conductor An electrode that is formed on the other side of the resistor and to which power is supplied; a thermal diffuser that is formed on the substrate on which the heating resistor is formed and diffuses heat generated from the heating resistor; A heater comprising: a heating resistor, the conductor, and a protective layer covering the thermal diffuser, wherein the thermal conductivity of the thermal diffuser is higher than that of the insulating substrate.
(2) The heater according to the technical concept (1), wherein the thermal conductivity of the thermal diffusion body is at least three times or more the thermal conductivity of the substrate.
According to the technical ideas (1) and (2) described above, since the thermal conductivity of the thermal diffuser is higher than that of the insulating substrate, the heat flows to the thermal diffuser and a substantially uniform temperature distribution can be obtained.

(3) A heat-resistant and long flat insulating substrate, a heating resistor formed on one surface of the insulating substrate, a conductor formed on both ends of the heating resistor, and the heat generation of the conductor An electrode formed on the other side of the resistor to which power is supplied, an insulating layer formed so as to cover the heating resistor and the conductor, and formed on the upper surface of the insulating layer and generated by the heating resistor. The heater according to the technical concept (1), wherein a glass protective layer having a surface roughness Rz of 2 μm or less is formed on the upper surface of the thermal diffuser.
(4) The heater according to the technical concept (1), in which a heat-resistant engineering plastic layer such as polyimide or polyamideimide is formed on the upper surface of the thermal diffuser.
According to the above technical ideas (3) and (4), a uniform temperature distribution of the heat generated from the heating resistor can be obtained by the thermal diffuser formed on the protective layer. In the case of the technical idea (3), since the surface roughness is fine, the fixing film travels smoothly. In the case of the technical idea (4), compared with the glass protective layer of the technical idea (3). Since it is soft, metal can be used as a fixing film.

The surface view for demonstrating the structure of one Embodiment regarding the heater of this invention. FIG. 2 is a cross-sectional view taken along line A-A ′ of FIG. 1. Explanatory drawing for demonstrating the effect of one Embodiment of the heater of this invention. The surface view for demonstrating the 1st modification of 1st Embodiment of the heater of this invention. B-B 'sectional drawing of FIG. The surface view for demonstrating the 2nd modification of 1st Embodiment of the heater of this invention. C-C 'sectional drawing of FIG. The surface view for demonstrating the structure of other embodiment regarding the heater of this invention. D-D 'sectional drawing of FIG. Explanatory drawing for demonstrating the effect of other embodiment of the heater of this invention. The surface view for demonstrating the modification of other embodiment of the heater of this invention. E-E 'sectional drawing of FIG. BRIEF DESCRIPTION OF THE DRAWINGS FIG. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram for explaining an embodiment of an image forming apparatus according to the present invention;

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Insulating board | substrate 12, 13 Heating resistor 14,15 Electrode 141,151,16 Connection conductor 17,18,61,81 Thermal diffusion body 19 Protection layer 41 Wiring pattern 111 Glass protection layer

Claims (4)

A long flat insulating substrate formed of a heat-resistant and insulating material;
A heating resistor formed on the longitudinal direction of the insulating substrate;
An electrode formed on the insulating substrate for supplying power to the heating resistor;
A thermal diffuser that is formed on the insulating substrate and diffuses heat generated from the heating resistor;
A heater comprising at least the heating resistor, the conductor, and a protective layer covering the thermal diffusion body. A heat-resistant and long flat insulating substrate;
A heating resistor having a thick film formed on one surface of the insulating substrate;
Conductors formed at both ends of the heating resistor;
An electrode formed on the other side of the heating resistor of the conductor and supplied with power;
An insulating layer formed so as to cover the heating resistor and the conductor;
A heater comprising: a heat diffusing body that is formed in or on the insulating layer and diffuses heat generated by the heating resistor. A heating roller;
The fixing heater according to claim 1 or 2, wherein a heating resistor disposed opposite to the heating roller is pressed against the heating roller;
A fixing device comprising: a fixing film movably provided between the fixing heater and the heating roller. Forming means for attaching toner to an electrostatic latent image formed on a medium and transferring the toner to a sheet to form a predetermined image;
4. A fixing device according to claim 3, wherein the toner is fixed by passing a sheet on which an image is formed while being pressed against the fixing heater through a fixing film by a pressure roller. Image forming apparatus.

Images