JP2010054567A - Ceramic heater, heating unit and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress rising of temperature in an end section that is equivalent to a paper non passing part. <P>SOLUTION: Heating resistors 12, 13 mainly composed of Ag and Pd alloy are formed in parallel to the longitudinal direction of a ceramic substrate 11 in a long flat plate state. The heating resistors 12, 13 are serially connected by having electrodes 14, 15 for energizing connected on one ends of the heating resistors 12, 13 and having a connection conductor 16 connected to the other ends. An overcoat layer 17 is formed on the heating resistors 12, 13. A plurality of projections 18 of the same material as the overcoat layer 17 are integrally formed on the overcoat layer 17. The projections 18 have their heights made gradually higher toward both ends in the longitudinal direction of the ceramic substrate 11. Thus, heat discharging property is improved by making the projections 18 higher in proportion to the end sections of the heater which are to be the paper non passing parts and which contribute to suppressing the temperature rise in the paper non passing pats. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a thin ceramic heater used in small equipment such as information equipment, home appliances and manufacturing equipment, and a heating device such as a printer, a copier, a facsimile, a rewritable card reader / writer, and the like mounted with the heater, Furthermore, the present invention relates to an image forming apparatus using this heating device.

The conventional ceramic heater smoothes the relationship between the size of bubbles generated in the overcoat layer by making bubbles on the heating resistor <bubbles on the substrate, and reducing the unevenness on the surface of the overcoat layer. The friction is reduced and it is transported smoothly. (For example, Patent Document 1)
JP 2006-92831 A

  The technique of the above-described Patent Document 1 performs printing because control is performed to wait for the sheet to pass until the temperature of the end is lowered to a predetermined value when the end corresponding to the non-sheet passing portion of the heater is heated. Was hindering speeding up.

  An object of the present invention is to provide a ceramic heater, a heating device using the heater, and an image formation using the heating device that can realize stable heating by suppressing the temperature rise at the end even when the printing speed is increased. To provide an apparatus.

  In order to solve the above-described problems, a ceramic heater according to the present invention includes a long flat plate-like ceramic substrate formed of a heat-resistant and insulating material, and a heating resistor formed in a thick film in the longitudinal direction on the ceramic substrate. A plurality of electrodes that supply power to both ends of the heating resistor, an overcoat layer that is formed on the insulating substrate leaving at least the electrode, and a flat upper surface that is integrally formed on the overcoat layer A convex portion, wherein the convex portion is formed so as to gradually increase in height along both longitudinal ends of the overcoat layer.

  The ceramic heater according to the present invention includes a long flat ceramic substrate formed of a heat-resistant and insulating material, a heating resistor formed in a thick film in the longitudinal direction on the ceramic substrate, and both ends of the heating resistor. At least opposite to the heating resistor on the ceramic substrate on the opposite side on which the heating resistor is formed, an electrode for supplying power to the substrate, an overcoat layer formed on the insulating substrate leaving at least the electrode A sliding layer formed at a position, and a plurality of convex portions with a flat upper surface formed integrally on the sliding layer, the convex portions being at both ends in the longitudinal direction of the overcoat layer It is characterized in that the height is gradually increased along the side.

  According to the present invention, the height of the convex portion for improving the slidability of the paper passing is made higher at the heater end portion which becomes the non-paper passing portion so as to improve the heat dissipation. It becomes possible to suppress the temperature rise of the part.

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

  1 to 4 are diagrams for explaining the first embodiment of the ceramic heater according to the present invention. FIG. 1 (a) is a configuration diagram, FIG. 1 (b) is a rear view of FIG. 2 (a) is a cross-sectional view taken along the line aa 'in FIG. 1, FIG. 2 (b) is a cross-sectional view taken along the line bb' in FIG. 1, and FIG. 3 is a cross-sectional view taken along the line cc 'in FIG.

  1 to 3, reference numeral 11 denotes a highly heat-resistant strip-shaped ceramic substrate which is a high-rigidity base material having electrical insulation properties such as a heat-resistant and electrically insulating material such as aluminum oxide, aluminum nitride, silicon nitride. .

  The ceramic substrate 11 has dimensions of, for example, a thickness of 1 mm, a width of 10 mm, and a length of 280 mm. 12 and 13 are silver-based materials such as silver (Ag) / palladium (Pd) formed in parallel along the longitudinal direction of the surface side of the ceramic substrate 11, and resistor pastes such as ruthenium-based and carbon-based materials. Is a belt-shaped heating resistor made of a thick film having a predetermined resistance value.

  The heating resistors 12 and 13 have dimensions of, for example, a thickness of 10 μm, a width of 2.5 mm, and a length of about 226 mm. Reference numerals 14 and 15 denote power feeding electrodes formed adjacent to one side of the ceramic substrate 11 in the non-contact state. The electrode 14 is integrally formed with the other end of the connection pattern 141 made of a good conductor film mainly composed of an Ag / Pd alloy or the like formed by layering one end on one end of the heating resistor 12.

  The electrode 15 is integrally formed with the other end of the connection pattern 151 made of a good conductor film mainly composed of Ag / Pd alloy or the like formed by layering one end on one end of the heating resistor 13. Yes.

  The other ends of the heating resistors 12 and 13 are connected using a connection pattern 16 that can be formed simultaneously with the same material as the connection patterns 141 and 151. With this connection, the heating resistors 12 and 13 are connected in series between the electrodes 14 and 15.

  17 is formed of a glass layer or a polyimide layer, for example, by thick film printing on the heating resistors 12 and 13 and the connection pattern 16 and the like leaving the electrodes 14 and 15 to provide electrical, mechanical and chemical protection. This is an overcoat layer to be performed.

  Reference numeral 18 denotes a plurality of convex portions having a flat upper surface integrally formed with the same material as the overcoat layer 17 on the surface of the overcoat layer 17. The convex portions 18 have a polygonal shape, and are arranged in, for example, four rows in the longitudinal direction of the ceramic substrate 11.

  The convex portion 18 is formed by, for example, a technique using thick film printing. The convex portions 18 are arranged in four rows in the longitudinal direction of the ceramic substrate 11 with the same length as the heating resistors 12 and 13. Further, the convex portions 18 are uniformly arranged from the upstream side to the downstream side of the ceramic substrate 11 shown in FIG.

  Further, as shown in FIG. 3 showing the cc ′ cross section in FIG. 1, the four rows of convex portions 18 are formed so as to gradually increase in the direction from the intermediate portion in the longitudinal direction of the ceramic substrate 11 toward both ends. Is done. That is, the relationship between the height h1 of the convex portion 18 shown in FIG. 2B and the height h2 of the convex portion 18 shown in FIG. 2B is set to h1 <h2.

  Although the number of the convex portions 18 is actually larger than the number shown in FIG. 1, the number of the convex portions 18 is reduced and shown here for easy understanding.

  As long as the convex portions 18 are arranged evenly and in a balanced manner on the overcoat layer 17, even if the ceramic substrate 11 is not arranged in a straight line in the longitudinal direction, it does not have a staggered or straight shape in the short direction. It doesn't matter. The convex part 18 should just be the number which can fully transfer the heat from the heating resistors 12 and 13.

  As described above, the overcoat layer 17 formed with the plurality of convex portions 18 can reduce the contact area with a fixing film, which is a heated body (not shown) that slides on the convex portions 18. The friction with the heating body can be reduced, and the slidability can be improved.

  Furthermore, the height of the convex portion 18 for improving the slidability of the paper passing is formed so as to be higher at the end of the heater that becomes the non-paper passing portion, so that the heat dissipation can be improved. It is possible to suppress the temperature rise at the paper passing portion.

  FIG. 4 is an explanatory diagram for explaining the effect of the amount of heat generated when the height of the convex portion 18 for improving the slidability of the sheet passing is made higher at the heater end that becomes the non-sheet passing portion. It is.

  In FIG. 4, La indicates the total length in the longitudinal direction generated by the heating resistors 12 and 13, Lb indicates a region of the sheet passing portion, and Lc indicates a region of the non-sheet passing portion. The broken line indicates the case where the height of the convex portion 18 is the same, and the solid line indicates the case of the present invention in which the height of the convex portion 18 on the non-sheet passing portion side is increased.

  In the region of the non-sheet passing portion Lc, the heat dissipation is improved because the surface area of the convex portion 18 is increased. For this reason, it is possible to prevent the amount of heat generated by the non-sheet passing portion Lc from becoming higher than that of the sheet passing portion Lb by causing the same action as that of the sheet passing portion Lb from which heat is removed by passing the sheet.

  5 and 6 illustrate a second embodiment relating to the ceramic heater of the present invention. 5A is a configuration diagram, FIG. 5B is a rear view of FIG. 5A, FIG. 6A is a cross-sectional view taken along the line dd ′ of FIG. 5, and FIG. 6B is e of FIG. -E 'sectional drawing. Constituent parts having the same functions as those in the above embodiment are given the same reference numerals, and different parts will be described here.

  In this embodiment, a glass layer or a polyimide layer is formed on the back surface of the ceramic substrate 11 on which the heating resistors 12 and 13 are formed, for example, by thick film printing, and performs electrical, mechanical, and chemical protection. The layer 19 is formed, and a plurality of convex portions 181 are formed on the sliding layer 19. The convex portion 181 is formed under the same conditions as the convex portion 18. That is, the convex portion 181 is formed by gradually increasing the height toward both ends in the longitudinal direction of the ceramic substrate 11.

  Also in this embodiment, not only can the slidability be improved on the convex portion 181, but the heat dissipation can be improved by forming the heater end portion that becomes a non-paper passing portion higher. It is possible to suppress the temperature rise in the non-sheet passing portion.

  7 and 8 describe a third embodiment relating to the ceramic heater of the present invention. 7A is a configuration diagram, FIG. 7B is a rear view of FIG. 7A, FIG. 8A is a cross-sectional view taken along line ff ′ of FIG. 7, and FIG. 8C is g of FIG. It is -g 'sectional drawing. Constituent parts having the same functions as those in the above embodiment are given the same reference numerals, and different parts will be described here.

  In this embodiment, the sliding layer 19 of the second embodiment of the ceramic heater of the present invention is removed, and the convex portion 182 is formed directly on the ceramic substrate 11. The convex portion 182 is formed on the surface of the ceramic substrate 11 opposite to the surface on which the heating resistors 12 and 13 are formed under the same conditions as the convex portion 181. That is, the convex portion 182 is not formed integrally with the sliding layer 19 but is formed directly on the ceramic substrate 11. The convex portions 182 are formed such that the height gradually increases toward both ends in the longitudinal direction of the ceramic substrate 11.

  In this case as well, not only can the slidability be improved on the convex portion 182, but the heat radiation performance can be improved by forming the heater end as a non-sheet passing portion higher. It is possible to suppress the temperature rise at the paper passing portion.

  Furthermore, the heat capacity due to the removal of the sliding layer 19 can be reduced. For this reason, the heat generated in the ceramic substrate 11 can be transferred to the fixing film, which is a heated body (not shown) that slides on the convex portion 182, so that heat conduction can be further suppressed, thereby improving efficiency. be able to.

  In each of the embodiments of the ceramic heater described above, the height of the convex portion is gradually increased toward both ends in the longitudinal direction of the ceramic substrate. The height of the convex portion may be the same, and the height of the convex portion of the non-paper passing portion may be higher than that of the paper passing portion.

  Next, an embodiment relating to the heating device of the present invention when the ceramic heater described in FIGS. 1 to 3 is mounted on the heating device 200 will be described with reference to the configuration diagram of FIG. 9. In the figure, reference numeral 100 denotes the ceramic heater described with reference to FIGS. 1 to 3, and the same portions are denoted by the same reference numerals and description thereof is omitted.

  Reference numeral 211 denotes a heat resistant material such as a polyimide resin that moves while the ceramic heater 100 is fixed to the bottom of the support 262 and is heated by pressure contact with the convex portion 18 of the overcoat layer 17 that is heated by supplying an AC voltage to the ceramic heater 100. It is a cylindrical fixing film wound in a circulatory manner in a roll form. Reference numeral 213 denotes a pressure roller having a heat resistant elastic material such as a silicone rubber layer 214 mounted on the surface thereof, and the ceramic heater 100 is juxtaposed with the fixing film 201 so as to face the rotating shaft 2105 of the pressure roller 213. Are mounted in a base (not shown). The pressure roller 213 is brought into pressure contact with the fixing film 201 based on a means (not shown) to form the nip portion N, and 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 through the fixing film 211 between the surface of the fixing film 211 disposed on the overcoat layer 17 and the silicone rubber layer 214, 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 213, the copy paper P is separated from the ceramic heater 100, the toner image To2 is naturally radiated and cooled and solidified again, and the fixing film 211 is also separated from the copy paper P.

  In this embodiment, it is possible to suppress the temperature rise in the non-sheet passing portion while improving the slidability between the fixing film and the ceramic heater.

  The ceramic heater of the present invention is not limited to the above-described embodiment. For example, the electrodes 14 and 15 may be disposed on both sides in the longitudinal direction of the ceramic substrate 11. The heating resistor of the ceramic heater has the connection patterns 141 and 154 extending in the longitudinal direction of the ceramic substrate 11, the heating resistor is wide in the longitudinal direction of the ceramic substrate 11, and the length is short in the ceramic substrate 11. The heating resistor may be connected to the connection pattern 141 at one end and the connection pattern 151 at the other end.

  Next, with reference to FIG. 10, an embodiment relating to an image forming apparatus of the present invention will be described, taking as an example a copying machine equipped with the heating device 200 of 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. 10, 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 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 receiving heat from the heating resistors 12 and 13, and characters and alphanumeric characters on the copy paper P surface. A copy image such as a symbol or a drawing is displayed.

  In this embodiment, when the printing speed is increased because a heating device that can obtain a reliable fixing property that suppresses heat generation in the non-sheet passing portion while improving the sliding property between the fixing film and the ceramic heater is used. However, it is possible to reduce the wear caused by the conveyance sheet and to prevent the occurrence of conveyance failure and fixing failure.

  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.

BRIEF DESCRIPTION OF THE DRAWINGS (a) for demonstrating the structure of 1st Embodiment regarding the ceramic heater of this invention is a block diagram, (b) is a rear view of (a). FIG. 2A is a cross-sectional view taken along the line a-a ′ in FIG. 1, and FIG. 2B is a cross-sectional view taken along the line b-b ′ in FIG. 1. C-c 'sectional drawing of FIG. Explanatory drawing for demonstrating the effect of this invention. (A) is a block diagram for describing 2nd Embodiment regarding the ceramic heater of this invention, (b) is a rear view of (a). (A) is d-d 'sectional drawing of FIG. 5, (b) is e-e' sectional drawing of FIG. (A) is a block diagram for demonstrating 3rd Embodiment regarding the ceramic heater of this invention, (b) is a rear view of (a). (A) is f-f 'sectional drawing of FIG. 7, (c) is g-g' sectional drawing of FIG. The block diagram for demonstrating one Embodiment regarding the heating apparatus of this invention. 1 is a configuration diagram for explaining an embodiment of an image forming apparatus according to the present invention.

Explanation of symbols

11 Ceramic substrate 12, 13 Heating resistor 14, 15 Electrode 141, 151, 16 Wiring pattern 17 Overcoat layer 18, 181, 182 Convex part 19 Sliding layer 100 Ceramic heater 200 Heating device 201 Fixing film 203 Pressure roller 300 Copier

Claims (6)

A long flat ceramic substrate made of heat-resistant and insulating material;
A heating resistor formed thick in the longitudinal direction on the ceramic substrate;
Electrodes for supplying power to both ends of the heating resistor;
An overcoat layer applied on the insulating substrate leaving at least the electrodes;
A plurality of convex portions having a flat upper surface formed integrally on the overcoat layer;
The ceramic heater is characterized in that the convex portion is formed so as to gradually increase in height along both longitudinal ends of the overcoat layer. A long flat ceramic substrate made of heat-resistant and insulating material;
A heating resistor formed thick in the longitudinal direction on the ceramic substrate;
Electrodes for supplying power to both ends of the heating resistor;
An overcoat layer applied on the insulating substrate leaving at least the electrodes;
A sliding layer formed at a position facing at least the heating resistor on the ceramic substrate on the opposite side on which the heating resistor is formed;
A plurality of convex portions having a flat upper surface formed integrally on the sliding layer,
The ceramic heater according to claim 1, wherein the convex portion is formed so as to gradually increase in height along both longitudinal ends of the overcoat layer.   3. The ceramic heater according to claim 2, wherein the convex portion is directly formed on the ceramic substrate on the back surface on which the overcoat layer is formed.   The said convex-shaped part is carrying out the polygonal shape, The corner | angular part of this polygonal shape has comprised the taper shape in the width direction of the said ceramic substrate, The Claim 1 characterized by the above-mentioned. Ceramic heater. The ceramic heater according to any one of claims 1 to 4,
A pressure roller disposed opposite to the ceramic heater and rotatably supported so as to press-contact the ceramic heater;
And a fixing film that is provided between the ceramic heater and the pressure roller and slides on the ceramic heater 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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