JP2004335397A - Heat roller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat roller wherein a temperature of a roller surface is suppressed lowered than a temperature threshold of a silicone rubber. <P>SOLUTION: The heat roller comprises a resistive element 11 consisting of: a first resistive element 13 in which a combined resistance or a resistance of a resistance wire material having a temperature coefficient of resistance of 100-500 PPM/°C is set to 10-40% of the combined resistance of the resistive element 11; and a second resistive element 15 in which a combined resistance or a resistance of a resistance wire material having a temperature coefficient of resistance of 3000-10000 PPM/°C is set to 90-60% of the combined resistance of the resistive element 11, which are connected in series. Using the heat roller, the first resistive element 13 rapidly heats the heat roller in a starting range so that the temperature of the roller surface is risen to 210°C within 180 seconds, and the second resistive element 15 increases the resistance of the resistive element 11 as the temperature of the roller surface increases, to reduce the current flowing through the resistive element 11 to allow the temperature of the roller surface to be maintained within a range of 210-350°C. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a heat roller for drying or fixing transfer ink by heating a recording medium on which an image is formed in a full-color card printer or the like.
[0002]
[Prior art]
FIG. 5 is a cross-sectional view showing the configuration of a conventional heat roller. Reference numeral 1 denotes a resistance element formed by winding a resistance wire 2 having a temperature coefficient of resistance of 250 PPM / ° C., and 4 denotes current welding to the terminals of the resistance wire 2, respectively. A heat-resistant lead wire 5 is connected to a metal case 5 having, for example, a metal bottomed cylindrical shape provided with a silicon rubber 6 having a temperature limit of 350 ° C. on its outer peripheral surface, and a lead 7 having the resistance element 1 inserted therein. A powdery filler for filling the case 5 with the wire 4 drawn out from the opening 5a, and a sealing material 8 for filling the opening 5a of the case 5 with the lead wire 4 drawn out and sealing the opening 5a. .
[0003]
In the conventional heat roller configured as described above, when a power of 250 W is supplied to the resistance element 1, the surface temperature of the silicon rubber 6, that is, the roller surface temperature becomes a temperature at which the transfer ink can be dried or fixed on a recording medium, for example, 210 ° C. In 139 seconds.
[0004]
Then, after detecting that the roller surface temperature has reached 210 ° C. by a temperature sensor or the like, the power supplied to the resistance wire 2 is controlled by the temperature controller so that the roller surface temperature is maintained at approximately 210 ° C. .
[0005]
[Problems to be solved by the invention]
By the way, if the temperature control device or the temperature sensor fails, 250 W of power is continuously supplied to the resistance wire 2 and the roller surface temperature exceeds 210 ° C. (see FIG. 6), but the resistance temperature coefficient is 250 PPM / ° C. Since the resistance change rate of the wire 2 is 2% and the resistance value of the resistance wire 2 hardly changes, 250 W of power is continuously supplied to the resistance wire 2 and the roller surface temperature also continues to rise.
[0006]
Therefore, the roller surface maximum temperature exceeds the temperature limit of the silicon rubber 6 of 350 ° C. and rises to 800 ° C., which is a so-called thermal runaway state of the heat roller (shown by a dashed line in the graph of FIG. 2), and the resistance element 1 and the silicone rubber 6, causing fires, etc., and secondary disasters such as destruction of devices or equipment around the heat roller.
[0007]
The present invention has been made in view of such a problem, and an object of the present invention is to provide a heat roller capable of suppressing a roller surface temperature to be equal to or lower than a temperature limit of silicon rubber.
[0008]
[Means for Solving the Problems]
Heat consisting of a resistance element in which a heat-resistant lead wire is connected to a resistance wire, a cylindrical case, and a filler for filling the case in which the resistance element is inserted inside and the lead wire is drawn out from an opening. In the roller, the resistance element includes a first resistance element having a resistance temperature coefficient of 100 to 500 PPM / ° C. or a resistance value of 10 to 40% of the resistance value of the resistance wire; Are connected in series with a second resistor element having a combined resistance value of the resistance wire rod of 3000-10000 PPM / ° C. or a resistance value of 90-60% of the combined resistance value of the resistor element.
[0009]
When power is supplied to the heat roller, the heat roller is quickly started up, and as the roller surface temperature rises, the resistance value is increased, and the power flowing through the resistance element is gradually reduced, so that the roller surface is gradually cooled. Since the temperature can be self-controlled to below the temperature limit of silicon rubber, the occurrence of secondary accidents, such as burning of resistor elements and silicon rubber, fires, and destruction of devices or equipment around the heat roller can be prevented. Power consumption can be reduced.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same reference numerals indicate the same parts.
[0011]
FIG. 1 is a cross-sectional view showing a configuration of a heat roller according to an embodiment of the present invention. Reference numeral 11 denotes a first resistance element 13 in which a resistance wire 12 is wound around a core 3, and a resistance wire 14 is wound around the core 3. A resistance element 4 is formed by connecting the turned second resistance element 15 in series, and currents 4 are supplied to the terminals of the resistance wire 12 of the first resistance element 13 and the terminals of the resistance wire 14 of the second resistance element 15, respectively. A heat-resistant lead wire 5 connected by welding or the like has a bottomed cylindrical case made of metal having, for example, a silicon rubber 6 having a temperature limit of 350 ° C. on its outer peripheral surface, and 7 has a resistance element 11 inserted therein. Is a powdery filler for filling the case 5 with the lead wire 4 drawn out from the opening 5a, and 8 is a sealing material for filling the opening 5a of the case 5 with the lead wire 4 drawn out and sealing the opening 5a. It is.
[0012]
(Example 1)
The resistance element 11 according to the first embodiment of the present invention is composed of two resistance elements each formed by winding a resistance wire 12 having a temperature coefficient of resistance of 250 PPM / ° C. around a core 3 so that the rate of change in resistance becomes 136%. And a second resistance element 15 composed of two resistance elements in which a resistance wire 14 having a temperature coefficient of resistance of 4500 PPM / ° C. is wound around the core 3.
[0013]
In the heat roller of the first embodiment, when the power of 255 W is supplied to the resistance element 11, the resistance value of the resistance element 11 increases as the surface temperature of the silicon rubber 6, that is, the roller surface temperature increases. The power flowing through the roller 11 gradually decreases, and the rise in the roller surface temperature also gradually decreases.
[0014]
Then, when the roller surface temperature reaches 410 ° C., the resistance value of the resistance element 11 also becomes substantially constant, and only 111 W of power flows through the resistance element 11. Regardless of whether or not, the maximum roller surface temperature is maintained at 410 ° C.
[0015]
During this time, it takes 192 seconds for the roller surface temperature to reach a temperature at which the transfer ink can be dried or fixed to the recording medium, for example, 210 ° C.
[0016]
(Example 2)
The resistance element 11 according to the second embodiment of the present invention includes a first resistance element formed by winding a resistance wire 12 having a temperature coefficient of resistance of 250 PPM / ° C. around a core 3 so that a resistance change rate is 194%. And a second resistance element 15 composed of three resistance elements in which a resistance wire 14 having a temperature coefficient of resistance of 4500 PPM / ° C. is wound around the core 3.
[0017]
In the heat roller of Example 2, when 290 W of electric power is supplied to the resistance element 11, the roller surface temperature of 210 ° C. is reached in 150 seconds as shown in FIG. 2, but the resistance value of the resistance element 11 is equal to the roller surface temperature. Rises as the temperature rises, so that the power flowing through the resistance element 11 gradually decreases, and the temperature of the roller surface also gradually increases.
[0018]
Then, when the roller surface temperature reaches 320 ° C., the resistance value of the resistance element 11 becomes substantially constant, and only 103 W of power flows through the resistance element 11. Regardless of whether or not, the maximum roller surface temperature is maintained at 320 ° C.
[0019]
(Example 3)
In the resistance element 11 according to the third embodiment of the present invention, four resistance elements in which a resistance wire 12 having a resistance temperature coefficient of 4500 PPM / ° C. is wound around the core 3 are connected in series so that the resistance change rate is 266%. It was done.
[0020]
In the heat roller of the third embodiment, when 340 W of power is supplied to the resistance element 11, the roller surface temperature of 210 ° C. is reached in 192 seconds, but the resistance value of the resistance element 11 increases as the roller surface temperature increases. As a result, the power flowing through the resistance element 11 gradually decreases, and the rise in the roller surface temperature also gradually decreases.
[0021]
Then, when the roller surface temperature reaches 308 ° C., the resistance value of the resistance element 11 also becomes substantially constant, and only 108 W of power flows through the resistance element 11. Regardless of whether or not, the maximum roller surface temperature is maintained at 308 ° C.
[0022]
(Example 4)
The resistance element 11 according to the fourth embodiment of the present invention includes a first resistance element including two resistance elements wound around a core 3 with a resistance temperature coefficient of 4500 PPM / ° C. so that the rate of change in resistance is 315%. And a second resistance element 15 composed of two resistance elements in which a resistance wire 14 having a temperature coefficient of resistance of 6700 PPM / ° C. is wound around the core 3.
[0023]
In the heat roller of Example 4, when 485 W of electric power is supplied to the resistance element 11, the roller surface temperature of 210 ° C. is reached in 168 seconds, but the resistance value of the resistance element 11 increases as the roller surface temperature increases. As a result, the power flowing through the resistance element 11 gradually decreases, and the rise in the roller surface temperature also gradually decreases.
[0024]
Then, when the roller surface temperature reaches 375 ° C., the resistance value of the resistance element 11 becomes substantially constant, and even if the power of 485 W is continuously supplied between the terminals of the resistance element 11, the resistance wire 12 and the resistance Since only 128 W of power flows through the wire 14, the roller surface maximum temperature is maintained at 375 ° C. regardless of whether or not the temperature controller, the temperature sensor, and the like have failed.
[0025]
(Example 5)
In the resistance element 11 of Example 5 of the present invention, the first resistance element 13 in which the resistance wire 12 is wound around the core 3 and the resistance wire 14 are wound around the core 3 such that the rate of change in resistance is 651%. Instead of the second resistance element 15, three PCT elements are connected in parallel.
[0026]
In the heat roller of Example 5, when 250 W of electric power is supplied to the resistance element 11, the roller surface temperature of 84 ° C. is reached in 180 seconds, but the resistance value of the resistance element 11 increases as the roller surface temperature increases. Therefore, the power flowing through the three PTC elements gradually decreases, and the rise in the roller surface temperature gradually decreases.
[0027]
Then, when the roller surface temperature reaches 130 ° C., the resistance value of the resistance element 11 becomes substantially constant, and even if the power of 250 W is continuously supplied between the terminals of the resistance element 11, the resistance wire 12 and the resistance Since only 32 W of power flows through the wire 14, the maximum roller surface temperature is maintained at 130 ° C. irrespective of whether or not the temperature controller, the temperature sensor, and the like have failed.
[0028]
FIG. 3 is a table showing the results of Examples 1 to 5 and the result of the conventional example.
[0029]
As is apparent from these results, the heat rollers of Examples 2, 4 and 5 satisfy the specification that the start-up time is within 180 seconds, and the maximum surface temperature of the rollers is such that the transfer ink is dried or fixed on the recording medium. The heat roller of the second embodiment satisfies the specification from 210 ° C. to 350 ° C., which is the temperature limit of the silicon rubber 6.
[0030]
As a result, only the heat roller of Example 2 satisfies the specification that the start-up time is within 180 seconds and the specification that the roller surface maximum temperature is 210 to 350 ° C.
[0031]
That is, according to the heat roller of the second embodiment, the first resistance element 13 made of the resistance wire 12 having a temperature coefficient of resistance of 250 PPM / ° C. rapidly heats the heat roller in the startup region (see FIG. 6). The temperature of the roller surface is raised to 210 ° C. within 180 seconds, and the second resistance element 15 made of the resistance wire 14 having a temperature coefficient of resistance of 4500 PPM / ° C. is a second resistance element with the rise of the roller surface temperature. By increasing the resistance value of No. 15, the resistance value of the resistance element 11 is increased, the power flowing through the resistance element 11 is reduced, and the roller surface temperature is maintained in the range of 210 to 350 ° C.
[0032]
It is to be noted that it is not limited to the heat roller of Example 2 that the specification that the start-up time is within 180 seconds and the specification that the roller surface maximum temperature is 210 to 350 ° C. A first resistance element 13 having a coefficient of resistance of 100 to 500 PPM / ° C. or a resistance of 10 to 40% of a resistance of the resistance element 11 and a temperature coefficient of resistance of 3000 to 10000 PPM / ° C. Any heat roller may be used as long as the resistance element 11 is formed by connecting in series a second resistance element 15 in which the combined resistance value of the resistance wire or the resistance value is 90 to 60% of the combined resistance value of the resistance element 11.
[0033]
FIG. 4 is a cross-sectional view showing a configuration of a heat roller according to another embodiment of the present invention. Reference numeral 16 denotes a single wound resistance obtained by winding a resistance wire 12 having a temperature coefficient of resistance of 250 PPM / ° C. around a core 3. A resistance element 4 is formed by connecting a first resistance element 13 and a PTC element 17 in series with each other. Reference numeral 4 denotes current welding to the terminal of the resistance wire 12 of the first resistance element 13 and the terminal of the PTC element 17, respectively. Is a heat-resistant lead wire, 5 is a metal bottomed cylindrical case having a silicon rubber 6 having a temperature limit of 350 ° C. on its outer peripheral surface, and 7 is a lead having the resistance element 11 inserted therein. A powdery filler for filling the case 5 with the wire 4 drawn out from the opening 5a, and a sealing material 8 for filling the opening 5a of the case 5 with the lead wire 4 drawn out and sealing the opening 5a. .
[0034]
The heat roller according to the present embodiment includes a second resistance element formed by winding a resistance wire 14 having a temperature coefficient of resistance of 4500 PPM / ° C. around the core 3 with the resistance temperature coefficient of the heat roller in Example 2 of the above-described embodiment. Instead of the resistance element 15, a PTC element 17 is used, and by using a PTC element 17 having the same or similar characteristics as the characteristics of the second resistance element 15, it functions similarly to the heat roller in the second embodiment. be able to.
[0035]
【The invention's effect】
As described above, according to the present invention, the heat roller is quickly started up, the resistance value is increased as the roller surface temperature increases, and the power flowing through the resistance element is gradually reduced. In addition, since the roller surface temperature can be self-controlled to below the temperature limit of silicon rubber, secondary accidents such as burnout of resistor elements and silicon rubber, fire, etc., and destruction of equipment or equipment around the heat roller, etc. This has the effect of preventing generation and the effect of reducing power consumption.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating a configuration of a heat roller according to an embodiment of the present invention. FIG. 2 is a time-temperature / resistance between a heat roller of Example 2 according to an embodiment of the present invention and a conventional heat roller. FIG. 3 is a graph showing a value / power characteristic. FIG. 3 is a comparison table between a heat roller according to one embodiment of the present invention and a conventional heat roller. FIG. 4 is a cross-sectional view illustrating a configuration of a heat roller according to another embodiment of the present invention. FIG. 5 is a cross-sectional view showing the structure of a conventional heat roller. FIG. 6 is a heating characteristic diagram of the heat roller.
3 core 4 lead wire 5 case 6 silicon rubber 7 filler 8 sealing material 11, 16 resistance element 12, 14 resistance wire 13 first resistance element 15 second resistance element 17 PCT element

Claims (2)

Heat consisting of a resistance element in which a heat-resistant lead wire is connected to a resistance wire, a cylindrical case, and a filler for filling the case in which the resistance element is inserted inside and the lead wire is drawn out from an opening. At the roller
The resistance element has a resistance temperature coefficient of 100 to 500 PPM / ° C., a first resistance element having a combined resistance value or a resistance value of 10 to 40% of the combined resistance value of the resistance element having a resistance temperature coefficient of 100 to 500 PPM / ° C. A heat roller comprising a series connection of a second resistance element having a combined resistance value of a resistance wire of 3000 to 10000 PPM / ° C or a resistance value of 90 to 60% of the combined resistance value of the resistance element. . The heat roller according to claim 1, wherein a PTC element is used instead of the second resistance element.

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