JP5010365B2 - Plate heater, heating device, image forming device - Google Patents

Description

The present invention uses a thin plate heater that is used by being mounted on small devices such as information equipment and home appliances, a heating device such as a printer, a copier, and a facsimile machine, and the heating device mounted with the plate heater. The present invention relates to an image forming apparatus.

Conventionally, a plate-like heater in which a heating resistor having a length in the short side and a width in the long direction is formed on a long flat ceramic insulating substrate is positive in the longitudinal direction on the insulating substrate. By forming a heating resistor having a temperature coefficient and connecting electrodes for power supply to both ends of the heating resistor in the short direction, the temperature distribution in the longitudinal direction of the insulating substrate is made uniform (for example, Patent Document 1).
JP-A-7-94260

The technique of the above-mentioned Patent Document 1 has a long distance until the heating resistor is connected in the wiring pattern far from the power supply electrode in the longitudinal direction of the insulating substrate, and is easily affected by the conductor resistance of the wiring pattern. . For this reason, a current easily flows through the wiring pattern on the side close to the electrode, and a large difference occurs between the temperature near the electrode and the temperature far from the electrode. For this reason, there has been a problem that the inclination of the temperature distribution in the longitudinal direction of the heater is large and a fixing defect occurs.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a plate heater which suppresses temperature unevenness in the longitudinal direction of the insulating substrate of the heat generating resistor formed in the short direction on the long flat plate-like insulating substrate, and this plate heater. It is an object of the present invention to provide a heating apparatus using the heating apparatus and an image forming apparatus using the heating apparatus.

In order to solve the above-described problems, a plate heater according to the present invention includes a long flat heat-resistant insulating substrate and a resistance formed on the insulating substrate in a shape extending in the longitudinal direction of the insulating substrate. A conductive first pattern having a temperature coefficient of 1000 ppm / ° C. or more and a shape extending in the longitudinal direction of the insulating substrate so as to be parallel to the first pattern, and formed on the insulating substrate; A conductive second pattern having a temperature coefficient of resistance of 1000 ppm / ° C. or more and a region on the insulating substrate between the first pattern and the second pattern, the first and second A conductive resistor provided on the insulating substrate so as to be connected to the heating resistor formed in contact with the first pattern and a point in the first pattern extending in the direction in which the first pattern extends. 3 patterns and the above A conductive fourth pattern provided on the insulating substrate so as to be connected to a point in the direction of extension of the second pattern of the second pattern, and the first pattern of the third pattern. A first electrode provided on the insulating substrate connected to a side opposite to the side connected to the pattern; and a side of the fourth pattern opposite to the side connected to the second pattern And a second electrode provided on the insulating substrate, and the fourth pattern is connected to the midpoint of the first pattern to which the third pattern is connected. The length dimension in the longitudinal direction of the insulating substrate with respect to the halfway point of the second pattern is a dimension adapted to the width of a sheet to be heated of a relatively small size. To do.

  According to the present invention, the temperature unevenness in the longitudinal direction of the insulating substrate of the heating resistor formed in the short direction on the long flat insulating substrate is reduced regardless of the paper size to be used. Uneven fixing can be prevented.

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

FIG. 1 and FIG. 2 are for explaining a first embodiment relating to the plate heater of the present invention. FIG. 1 (a) is a top view, FIG. 1 (b) is a rear view, and FIG. It is xx 'sectional drawing of.
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), etc. This is a flat strip-shaped insulating substrate such as a highly rigid ceramic. Reference numerals 12 and 13 arranged on both sides in the longitudinal direction of the insulating substrate 11 are power supply electrodes made of a good conductor film mainly composed of silver or the like. 14 and 15 are wiring patterns formed of a material having a silver (Ag) content of 90 wt% or more in parallel with each other in the non-contact state on both sides in the longitudinal direction of the insulating substrate 11.

  The electrodes 12 and 13 and the wiring patterns 14 and 15 are formed on the surface of one side of the insulating substrate 11 in different states. The electrodes 12 and 13 and the wiring patterns 14 and 15 can be formed in a state where they are fixed on the insulating substrate 11 by applying a conductive paste on the insulating substrate 11 and firing it.

  As shown in FIG. 1B, the connection pattern 16 is provided across the electrode 12 and the wiring pattern 15 at a position facing a part of the electrode 12 and the wiring pattern 15 in the longitudinal direction across the insulating substrate 11. Form. Similarly, a connection pattern 17 is formed across the electrode 13 and the wiring pattern 14 at a position facing a part of the electrode 13 and the wiring pattern 14 in the longitudinal direction across the insulating substrate 11.

  The electrode 12 and the connection pattern 16 are electrically connected through a through hole 181, and the wiring pattern 15 and the connection pattern 16 are electrically connected through a through hole 182 as shown in FIG. 2. The electrode 13 and the connection pattern 17 are electrically connected through a through hole 191, and the wiring pattern 14 and the connection pattern 17 are electrically connected through a through hole 192.

20 is screen-printed with a resistor paste such as ruthenium oxide (RuO ₂ ) having a relatively high resistance value formed in parallel along the longitudinal direction of the insulating substrate 11 between the wiring patterns 14 and 15, And a wide heating resistor having a predetermined resistance value and a film thickness of about 10 μm. The resistance temperature coefficient of the wiring patterns 14 and 15 is set to a value of 1000 ppm / ° C. or more.

  No. 21 is formed so as to cover the wiring patterns 14 and 15 and the heating resistor 20, and has a glass layer thickness of about 20 μm to 100 μm and an excellent thermal conductivity such as alumina having a thermal conductivity of, for example, 2 W / m · K or more. By adding 25 to 35 wt% of an inorganic oxide filler, it is an overcoat layer such as glass whose slidability is improved. The overcoat layer 21 protects the wiring patterns 14 and 15 and the heating resistor 20 mechanically, chemically, and electrically.

  In FIG. 1, t1 in the heating resistor 20 indicates an area corresponding to a width necessary for fixing a postcard size paper, for example, and the areas t2 and t3 are, for example, A4 size paper combined with the area t1. Is provided with a width of a region t4 (= t1 + t2 + t3) corresponding to a width of a size at which is fixed. The through holes 182 and 192 are formed at positions corresponding to both ends of the region t1.

  Here, the operation of the plate heater configured as described above will be described. From the electrode 12 through the through hole 181, the connection pattern 16, the through hole 182, and the wiring pattern 15, and from the electrode 13 through the through hole 191, the connection pattern 17, the through hole 192, and the wiring pattern 14. When the other heating resistor 20 is energized, the heating resistor 20 generates heat.

  With the heating resistor 20 energized, the overcoat layer 21 is slid with a postcard. Since the postcard has the width of the region t1, the temperature of the heating resistor 20 at the positions of the through holes 182 and 192, which are power supply points, is slightly higher, but the temperature is deprived of the paper and the temperature distribution in the region t1 is almost uniform. Become. In postcards, the temperature rises in areas t2 and t3 where paper does not pass. Since the wiring patterns 14 and 15 have a positive resistance temperature coefficient, the resistance value increases and the current decreases as the wiring patterns 14 and 15 rise in temperature. As the current decreases, the temperature rise of the heating resistor 20 can be suppressed.

  Next, consider a case where an A4 size sheet is slid on the overcoat layer 21 in the region t4. The temperature of the heating resistor 20 at the positions of the through holes 182 and 192 serving as power feeding points is slightly higher, but the temperature is deprived of the paper and the temperature distribution in the region t1 becomes substantially uniform. Further, the temperature rise of the wiring patterns 14 and 15 in the regions t2 and t3 is suppressed by the paper and the current drop is also suppressed, and the temperature distribution in this region can be suppressed to obtain a temperature distribution almost the same as that of the region t1.

  FIG. 3 shows the present invention and the conventional insulating substrate 11 when the resistance value of the heating resistor 20 is 2.6Ω, the length is 1 mm, the width is 220 mm, the wiring pattern length is 220 mm, and the width is 2.3 mm. The result of having measured the temperature nonuniformity of the longitudinal direction is shown. In FIG. 3, the horizontal axis represents the width direction of the heating resistor 20, and the vertical axis represents the temperature change at each point in the width direction of the heating resistor 20 when the maximum temperature is 1.0.

  As shown in FIG. 3, in the prior art, as the temperature near the electrode is higher and farther away, the temperature decreases more markedly, and the temperature unevenness is about 33%. In the present invention, there is a temperature peak at the arrow a1 of the through hole 182 and the arrow a2 of the through hole 192, and a slight temperature drop is observed as the distance from the through holes 182 and 192 increases, but the temperature unevenness is reduced to about 8%. We were able to.

  In this embodiment, even if a heating resistor formed in a short length on a long flat plate-like insulating substrate is used, temperature variation of the heating resistor is suppressed to be small regardless of the paper size to be used. Is possible.

  4 and 5 are for explaining a second embodiment relating to the plate heater of the present invention. FIG. 4 (a) is a top view, FIG. 4 (b) is a rear view, and FIG. FIG. Parts having the same functions as those in FIG.

  In this embodiment, the electrodes 12 and 13 are formed close to one side of the insulating substrate 11 in the longitudinal direction.

  That is, the electrode 12 and the wiring pattern 15 are connected through the through holes 181 and 182, and the electrode 13 and the wiring pattern 14 are connected through the through holes 191 and 192. The positions of the through holes 182 and 192 are formed in a portion corresponding to the width of the postcard size, for example.

  In this embodiment, even when the power supply electrode is formed close to one side of the insulating substrate, it is possible to reduce temperature unevenness over the entire width of the heating resistor regardless of the paper size. Become.

  6 and 7 are for explaining a third embodiment relating to the plate heater of the present invention. FIG. 6 is a top view and FIG. 7 is a z-z ′ sectional view of FIG. 6. In addition, the same code | symbol is attached | subjected and demonstrated about the same component as 1st Embodiment of the above plate-shaped heater.

  In this embodiment, the same effects as those of the above-described embodiments are obtained without providing a through hole.

  That is, in a non-contact state in parallel to the outside of the wiring patterns 14 and 15 from the electrodes 12 and 13 formed on both sides in the longitudinal direction of the insulating substrate 11 on the surface of the same insulating substrate 11 on which the wiring patterns 14 and 15 are formed. Connection patterns 61 and 62 extending in the longitudinal direction are formed. The connection patterns 61 and 62 and the wiring patterns 14 and 15 are connected using the connection patterns 63 and 64 at positions corresponding to the width of the postcard size, for example.

  The electrode 12, the connection pattern 61, the connection pattern 63, and the wiring pattern 14 may be integrally formed and formed simultaneously. Further, the electrode 13, the connection pattern 62, the connection pattern 64, and the wiring pattern 15 may be integrally formed at the same time.

  When the heating resistor 20 is energized, if the overcoat layer 21 is slid with a postcard, the temperature of the heating resistor 20 at the positions of the connection patterns 63 and 64 where the postcard is the width of the region t1 and serves as a feeding point. Although slightly higher, the paper is deprived of the temperature and the temperature distribution in the region t1 becomes substantially uniform. In the postcard, the temperature rises in areas t2 and t3 where paper is not passed. However, since the wiring patterns 14 and 15 have a positive resistance temperature coefficient, the resistance value increases and the current decreases as the wiring patterns 14 and 15 rise in temperature. As the current decreases, the temperature rise of the heating resistor 20 can be suppressed.

  When the A4 size paper slides on the overcoat layer 21 in the region t4, the temperature of the heating resistor 20 at the positions of the connection patterns 63 and 64 serving as power feeding points is slightly high, but the paper is deprived of the temperature. The temperature distribution in the region t1 is almost uniform. Further, the temperature rise of the wiring patterns 14 and 15 in the regions t2 and t3 is suppressed by the paper and the current drop is also suppressed, and the temperature distribution in this region can be suppressed to obtain a temperature distribution almost the same as that of the region t1.

  In this embodiment, power is supplied at a portion corresponding to a small paper width on the same surface of the insulating substrate, and temperature unevenness over the entire width of the heating resistor is reduced regardless of the large and small paper sizes. It becomes possible. Further, since it is possible to form a connection pattern corresponding to the role of a through hole at the same time as an electrode or a wiring pattern, an improvement in productivity can be expected.

  Next, with reference to FIG. 8, an embodiment of the heating device of the present invention when the plate heater described above is mounted on the heating device 200 will be described. Reference numeral 100 in the figure denotes the plate heater described with reference to FIGS. 1 and 2, and the same portions are denoted by the same reference numerals and the description thereof is omitted.

  FIG. 8 is a cross-sectional view for explaining an embodiment in which the plate heater of the present invention is a heating device 200 for toner fixing.

  In FIG. 8, reference numeral 201 denotes a plate heater 100 fixed to the bottom of a support 202, an AC voltage is supplied to the plate heater 100, and moves while being pressed and heated by the sliding layer 18 of the heated plate heater 100. This is a cylindrical fixing film in which a heat-resistant sheet of polyimide resin or the like is rolled to be circulated. Reference numeral 203 denotes a pressure roller having a heat resistant elastic material, for example, a silicone rubber layer 204 fitted on the surface thereof. The plate heater 100 is opposed to the fixing film 201 so as to face the rotating shaft 205 of the pressure roller 203. They are mounted side by side in a base (not shown). The pressure roller 203 is brought into pressure contact with the fixing film 201 based on a means (not shown) to form a nip portion, 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 plate heater 100 through the fixing film 201 between the surface of the fixing film 201 disposed on the sliding layer 18 and the silicone rubber layer 204, and at least the surface portion thereof. 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 plate heater 100, the toner image To2 is naturally radiated and cooled and solidified again, and the fixing film 201 is also separated from the copy paper P.

  In this embodiment, the fixing property is improved by using a plate heater with less temperature unevenness in the longitudinal direction of the heating resistor formed in the short direction on the long flat insulating substrate. be able to.

  Next, with reference to FIG. 9, an image forming apparatus according to the present invention will be described using a copying machine equipped with the heating device 200 according to the present invention as an example. 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. 9, 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. 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 plate 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 plate heater 100 and the pressure roller 203 is melted by receiving heat from the heating resistor 12, and is printed with letters, alphanumeric characters, Copy images such as symbols and drawings are displayed.

  In this embodiment, the fixing device is excellent in fixability by using the heating device with the plate heater 100 using the heating resistor having the length formed in the short direction of the insulating substrate and the width formed in the longitudinal direction of the insulating substrate. An image forming apparatus can be realized.

  The plate heater is used for fixing image forming apparatuses such as copying machines, but is not limited to this. For household appliances, precision equipment for business use and experiments, equipment for chemical reaction, etc. It can be used as a heat source for heating and heat retention.

BRIEF DESCRIPTION OF THE DRAWINGS It is for demonstrating 1st Embodiment regarding the plate-shaped heater of this invention, (a) is a top view, (b) is a rear view. X-x 'sectional drawing of FIG. Explanatory drawing for demonstrating the effect of this invention. It is for demonstrating 2nd Embodiment regarding the plate-shaped heater of this invention, (a) is a top view, (b) is a rear view. FIG. 5 is a cross-sectional view taken along the line y-y ′ in FIG. 4. The top view for demonstrating 3rd Embodiment regarding the plate-shaped heater of this invention. FIG. 7 is a z-z ′ sectional view of FIG. 6. Explanatory drawing for demonstrating one Embodiment regarding the heating apparatus of this invention. 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 Electrode 14,15 Wiring pattern 16,17,63,64 Connection pattern 181,182,191,192 Through hole 20 Heating resistor 21 Overcoat layer 63,64 Connection pattern 100 Plate heater 200 Heating device 300 copier

Claims (5)

A long flat heat-resistant insulating substrate;
A conductive first pattern formed on the insulating substrate in a shape extending in the longitudinal direction of the insulating substrate and having a resistance temperature coefficient of 1000 ppm / ° C. or more ;
A conductive second pattern formed on the insulating substrate in a shape extending in the longitudinal direction of the insulating substrate so as to be parallel to the first pattern, and having a resistance temperature coefficient of 1000 ppm / ° C. or more ; ,
A heating resistor formed in contact with the first and second patterns in a region on the insulating substrate between the first pattern and the second pattern ;
A conductive third pattern provided on the insulating substrate so as to be connected to a point in the direction of extension of the first pattern of the first pattern;
A conductive fourth pattern provided on the insulating substrate so as to be connected to a point in the second pattern extending in the direction in which the second pattern extends;
A first electrode provided on the insulating substrate connected to a side of the third pattern opposite to the side connected to the first pattern ;
A second electrode provided on the insulating substrate connected to a side of the fourth pattern opposite to a side connected to the second pattern ,
Length in the longitudinal direction of the insulating substrate between the halfway point of the first pattern to which the third pattern is connected and the halfway point of the second pattern to which the fourth pattern is connected A plate-like heater, characterized in that the dimensions are adjusted to the width of a sheet to be heated of a relatively small size. The third pattern is connected to the first pattern through a first through hole provided in the insulating substrate;
The plate heater according to claim 1, wherein the fourth pattern is connected to the second pattern through a second through hole provided in the insulating substrate . The third pattern is formed on the same surface as the surface on which the first pattern is provided on the insulating substrate;
The plate heater according to claim 1, wherein the fourth pattern is formed on the same surface as the surface on the insulating substrate on which the second pattern is provided . A pressure roller,
The heater according to any one of claims 1 to 3 , wherein the heating resistor is disposed so as to face the pressure roller.
Heating apparatus characterized by comprising a fixing film is movable between said pressure roller and said heater. Image forming means for forming the images by transferring further the toner by adhering toner to the electrostatic latent image formed on the medium on the sheet,
A heating device according to claim 4,
That the paper on which the image has been formed, said by the pressure roller is passed while in pressure contact with the heater via the fixing film, and in so that by fixing the toner to the paper
An image forming apparatus comprising.

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