JP2001051544A - Fixing device, temperature control method and temperature controller for fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a fixing device capable of avoiding the temperature excessive rise of a paper non-passing part on the surface of a heating roller when narrow paper is made to consecutively pass with simple constitution, avoiding the temperature drop of the surface of the heating roller when the paper consecutively passes, requiring the small electromotive force at the time of cooling and eliminating the need of providing a current limit circuit in a power source, and a temperature control method and a temperature controller for the fixing device capable of appropriately controlling the temperature of the heating roller of the fixing device. SOLUTION: This fixing device is equipped with the heating roller 1 and a pressure roller 2 fixing a transferred image to transfer paper with heat, and a temperature detection control means 3 detecting and controlling the temperature on the roller 1. In such a case, the heating element of the roller 1 is formed of a non-metallic heating element whose electric resistance value is lowered with temperature rise, and the control means 3 is disposed at the paper non- passing part on the outer periphery of the roller 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device using a heating roller and a pressure roller in a fixing unit such as an electronic copying machine and a laser beam printer (hereinafter abbreviated as LBP), a method of controlling the temperature of the fixing device, and It relates to a temperature control device.

[0002]

2. Description of the Related Art Conventionally, as a heating roller in a fixing unit of an electronic copying machine or an LBP, a roller having a metal core covered with a fluororesin sleeve to improve the releasability of toner has been known.

[0003] A conventional roller of this type is prepared by mounting a fluororesin heat-shrinkable tube on a metal core, as shown in, for example, JP-A-59-198118, and then melting the melting point of the resin. It is manufactured by a method in which the resin is shrunk and fixed at a temperature lower than the melting point, and is further heated to a temperature higher than the melting point of the resin and fused.

[0004]

In a fixing device using a conventional heating roller manufactured by such a method, since a heating element such as a halogen lamp is used as a heat source, the surface of the roller is fixed. In order to raise the temperature, a warm-up time of 1 to 10 minutes is required,
There is a problem that the power consumption is as large as about 1200 W (watt). For this reason, various heating rollers have been proposed in which a heating layer is provided on the roller itself to heat the heating layer to a temperature of about 160 ° C., which is a temperature at which fixing can be performed in a short time, and heat is applied to the heating layer. For example, JP
Japanese Patent Application Publication No. -104984 discloses a metal pipe, an insulating layer formed on the outer peripheral surface of the metal pipe, a heating resistor layer formed outside the insulating layer, and a heating resistor. Disclosed is a heating roller including a heat-resistant high-release resin layer formed outside the layer and an electrode electrically connected to the heating resistor layer. However, the manufacturing method of the roller exemplified in Japanese Patent Application Laid-Open No.
A heating resistor (conductive paste) made of Ag is applied together with a binder, and a polyimide film is coated thereon.
After heating to around 00 ° C, the heating resistor sandwiched by the polyimide film is attached to the outer peripheral surface of the aluminum tube, and the manufacturing process is complicated.
Since the film is attached, a seam (seam) is generated, so that there is a problem that the film is expensive and the heat generation performance is not stable. Further, in this manufacturing method, since the seam between the heating element sheets is in the outer layer, there is a problem that an image at this location becomes unclear.

Japanese Patent Application Laid-Open No. 56-126286 discloses a heating roller in which a sheet heating element layer is adhered to the inner peripheral surface of a metal pipe via an insulating layer. However, the exemplified manufacturing method is to bond a heating element made of stainless steel foil to an insulating layer made of silicone rubber. In this case, it is necessary to use a heat-resistant adhesive such as an epoxy-based adhesive, so that the durability is increased. Inferior properties and the difficulty in the process of bonding to the inner surface easily cause partial exfoliation, and the amount of heat radiated at that portion is reduced. To solve this inconvenience,
Japanese Patent Application Laid-Open No. Hei 9-138605 discloses a heating method in which a heat-resistant insulating layer provided with a heating element disposed on the inner peripheral surface of a metal pipe, and a pressure contact body made of rubber or foamed rubber is mounted on the inner surface of the heat-resistant insulating layer. A roller is disclosed. However,
In this configuration, when the heating roller is used for a long period of time, there is a problem in that the adhesive strength is reduced due to thermal deterioration of the press contact body, and the heating element layer adhered to the inner peripheral surface of the metal pipe falls off.

In JP-A-10-333472 and JP-A-11-15318, when narrow paper such as postcards or B5 size paper is continuously passed, the non-paper passing portion of the heating roller is overheated together with the passing of paper. In order to prevent
A fixing device is disclosed in which a plurality of heating layers having different widths and positions are provided inside through an insulating layer, and a heating roller that separately supplies power to the plurality of heating layers. In such a fixing device, an excessive temperature rise in the non-sheet passing portion can be avoided, but a temperature drop in the sheet passing portion during continuous sheet passing cannot be avoided, and an inexpensive fixing device having a complicated structure is required. There was a problem that stable supply was not possible.

Further, the resistance-temperature characteristics of the heating elements of the above-mentioned prior art examples have positive characteristics, and the resistance value tends to increase as the temperature rises, that is, the current value tends to decrease as the temperature rises. . For this reason, there has been a problem that the electromotive force at the time of cooling becomes large and it is necessary to provide a current limiting circuit in the power supply. Further, when a plurality of sheets of paper are passed to fix an image while the heat generating roller is in use, the temperature of the paper passing portion of the heat generating roller decreases, and the resistance value r of the heat generating element in that part becomes non-paper. Since the current I is constant, the calorific value P of the paper passing portion, that is, P = r · I ² (J), is further reduced because the current I is constant. There is a disadvantage that non-sheet passing portions are high and non-sheet passing portions are low, which promotes non-uniformity.

SUMMARY OF THE INVENTION The present invention has been made in view of these points, and it is possible to avoid an excessive temperature rise in a non-sheet passing portion on the surface of a heating roller when a narrow sheet is continuously passed with a simple configuration. And a fixing device in which the temperature of the surface of the heating roller during continuous paper passing can be prevented from being lowered, and the electromotive force at the time of cooling is small and there is no need to provide a current limiting circuit in the power supply. And

Another object of the present invention is to provide a fixing device temperature control method and a temperature control device capable of appropriately controlling the temperature of the heating roller of the fixing device.

[0010]

The inventor of the present invention has made intensive studies to solve the problems such as the temperature drop in the paper passing portion and the excessive temperature rise in the non-paper passing portion. As a result, the heating element of the heating roller was heated. By forming a non-metallic heating element whose electric resistance value decreases with the temperature, a temperature sensor such as a temperature sensor disposed on the outer periphery of the heating roller is installed in the non-sheet passing portion to control the temperature. Temperature detecting means, such as another temperature sensor, can be installed in the paper passing section on the outer periphery of the heating roller to prevent excessive temperature rise in the paper passing section, and the temperature detecting means provided in the paper passing section It has been found that by controlling the temperature of the pressure roller having the heat generating layer or the auxiliary heat roller for heating the pressure roller, it is possible to avoid excessive temperature rise in the non-sheet passing portion, thereby completing the present invention. .

Specifically, the fixing device according to the first aspect of the present invention includes a heating roller and a pressure roller for fixing a transferred image to transfer paper by heat, and a temperature for detecting and controlling a temperature on the heating roller. In a fixing device having detection control means, a heating element of the heating roller is formed of a non-metallic heating element whose electric resistance value decreases with increasing temperature, and the temperature detection control means It is characterized in that it is disposed in the non-paper passing portion. By using this non-metallic heating element, the electromotive force at the time of cooling can be reduced, the temperature at the surface of the paper passing portion of the heating roller at the time of continuous paper passing can be reduced, and narrow paper can be continuously fed. In this case, it is possible to avoid excessive temperature rise in the non-paper passing area on the surface of the heating roller, or to install a temperature sensor or other temperature detection control By controlling, it is possible to avoid excessive temperature rise of the non-sheet passing portion.

Further, in the fixing device according to the present invention, a heating roller for fixing a transferred image to transfer paper by heat, a pressure roller having a heating element, and a temperature on the heating roller are detected and controlled. In the fixing device having a temperature detection control unit, the heating elements of the heating roller and the pressure roller are each formed of a non-metallic heating element whose electric resistance value decreases as the temperature rises. The temperature detection control means is disposed in a non-paper passing portion on the outer periphery of the heating roller, and another temperature control detection means is disposed in a paper passing portion on the outer periphery of the heating roller, and is disposed in the paper passing portion. The temperature of the pressure roller is controlled by the provided temperature detection control means. By using this non-metallic heating element, the electromotive force at the time of cooling can be reduced, the temperature of the surface of the paper passing portion of the heating roller and the pressure roller at the time of continuous paper passing can be avoided, and the narrow paper can be used. Overheating of the surface of the heating roller and the non-paper passing portion of the surface of the pressure roller when paper is continuously passed, and the use of temperature detection means such as a temperature sensor By controlling the temperature by installing it in the paper-passing section, it is possible to avoid excessive temperature rise in the non-paper-passing section, and install temperature detection control means such as another temperature sensor in the paper-passing section on the outer periphery of the heating roller. Then, by controlling the temperature of the pressure roller having the heat generating layer by the temperature detection control means disposed in the paper passing portion,
Excessive temperature rise of the non-sheet passing portion can be avoided.

Further, in the fixing device according to the third aspect, a heating roller and a pressure roller for fixing a transferred image to transfer paper by heat, and a temperature detection control for detecting and controlling a temperature on the heating roller. The heating element of the heating roller is formed of a non-metallic heating element whose electric resistance value decreases with increasing temperature, and an auxiliary heat roller for heating the pressure roller is provided. And the temperature detection control means on the heating roller is disposed in a non-paper passing portion on the outer periphery of the heating roller, and another temperature detection control means is disposed in a paper passing portion on the outer periphery of the heating roller. The temperature of the auxiliary heat roller disposed on the pressure roller is controlled by the temperature detecting means disposed in the paper passing portion. By using this non-metallic heating element, the electromotive force at the time of cooling can be reduced, the temperature at the surface of the paper passing portion of the heating roller at the time of continuous paper passing can be reduced, and narrow paper can be continuously fed. In this case, it is possible to avoid excessive temperature rise in the non-paper passing area on the surface of the heating roller, and to install a temperature sensor such as a temperature sensor on the outer circumference of the heating roller in the non-paper passing area to control the temperature. By doing so, it is possible to avoid excessive temperature rise in the non-sheet passing portion, and to install a temperature detection control means such as another temperature sensor in the sheet passing portion on the outer periphery of the heating roller to distribute the temperature in the sheet passing portion. By controlling the temperature of the auxiliary heat roller for heating the pressure roller by the provided temperature detection control means, it is possible to avoid an excessive temperature rise in the non-sheet passing portion.

According to a fourth aspect of the present invention, there is provided a fixing device according to the first aspect, the second aspect or the third aspect.
The non-metallic heating element of the heating roller is formed in a layered shape on the outer or inner periphery of a metal core having an insulating layer. This makes it possible to more appropriately control the temperature of the heating roller.

According to a fifth aspect of the present invention, in the fixing device according to the second aspect, the pressure roller has a heat generating layer on an outer periphery or an inner periphery of a core having an insulating layer. This makes it possible to more appropriately control the temperature of the heating roller.

According to a sixth aspect of the present invention, there is provided a fixing device according to any one of the first to fifth aspects.
The heat generating layer is a conductive tube made of polyimide or polyamide imide. Thus, the heat generation layer can be easily formed, and the temperature can be appropriately controlled.

According to a seventh aspect of the present invention, in the fixing device according to the sixth aspect, the conductive tube is a seamless tube having a surface resistance of 20 Ω / □ or less. Thereby, the heating value of the conductive tube can be freely controlled and heated.

Further, in the temperature control method for a fixing device according to the present invention, a heating roller and a pressure roller for fixing a transferred image to transfer paper by heat, and detecting and controlling the temperature on the heating roller. A heating element of the heating roller is formed of a non-metallic heating element whose electric resistance value decreases as the temperature rises, wherein the temperature detection control means In a temperature control method for controlling the temperature of a fixing device provided in a non-paper passing portion on the outer periphery of a roller, the temperature detection control means detects the temperature of the heating roller and simultaneously supplies current to the non-metallic heating element. While the current value is detected by the current sensor, the state of energization to the non-metallic heating element is controlled to maintain the surface temperature of the heating roller's paper passing portion and the surface temperature of the non-paper passing portion uniformly. Characterized by temperature control so that.

In the temperature control device for a fixing device according to the ninth aspect, a heating roller and a pressure roller for fixing a transferred image to transfer paper by heat, and detecting and controlling the temperature on the heating roller. A heating element of the heating roller is formed of a non-metallic heating element whose electric resistance value decreases as the temperature rises, wherein the temperature detection control means In a temperature control device for controlling the temperature of a fixing device provided in a non-sheet passing portion on the outer periphery of a roller, the temperature detection control means for detecting the temperature of the heating roller, and energization of the non-metallic heating element A current sensor for detecting a current value; a current control circuit for controlling a state of energization to the non-metallic heating element; and a detected temperature of the heating roller and a communication to the non-metallic heating element. And having a control circuit for temperature control so as to maintain a uniform surface temperature of the heating roller in response to the current value.

By operating the temperature control device of the present invention by the temperature control method, the surface temperature of the heating roller can be reliably maintained uniformly.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on examples.

Embodiment 1 FIGS. 1 to 3 show an embodiment of the present invention.

The present embodiment is applied to a fixing device of an electronic copying machine.

The fixing device of this embodiment includes a heating roller 1 and a pressure roller 2, and a temperature sensor 3 as a temperature detection control unit is provided on the surface of the heating roller 1.

The heating roller 1 is prepared by preparing an iron (material: STKM) metal core 1a having an outer diameter of 40 mm and a wall thickness of 0.7 mm, and using PFA (tetrafluoroethylene-perfluoroalkylvinyl ether) around the metal core 1a. An insulating layer 1c made of a polymer) is coated. Further, the outer periphery of the insulating layer 1c is coated with a conductive polyimide tube 1d as a heating layer of a non-metallic heating element.
A fluororesin tube 1e made of A is covered.

More specifically, the conductive polyimide tube 1d used for the heating layer is a seamless tube made of a polyimide resin in which a conductive filler such as conductive carbon is dispersed by about 10 to 30% by weight. It was molded by a solution casting method as disclosed in JP-A-202513. That is, first, a polyamic acid, which is a precursor of polyimide, is dissolved in a solvent such as N-methyl-2-pyrrolidone to form a polyamic acid solution, and then Ketjen black (AKZO), which is a conductive carbon black, is used.
(Trade name, manufactured by the Netherlands) and dispersed in a ball mill, then put into the cylinder of a rotary centrifugal molding machine,
It is cast on the inner peripheral surface of the cylinder by the rotation of the centrifugal molding machine,
The cast dispersion was heated on the inner peripheral surface of the cylinder to remove the solvent to some extent, thereby obtaining a polyamic acid tube. Next, after taking out the tube, the tube was heat-treated with a hot air drier and cured by advancing an imidization reaction to obtain a conductive seamless tube having an inner diameter of 40 mm, a thickness of 110 μm, and a length of 370 mm. The surface resistance of the tube was measured with a Loresta AP (trade name, manufactured by Mitsubishi Chemical Corporation) and found to be 5Ω / □.

Next, an iron (material: STKM) metal core 1a having an outer diameter of 40 mm and a wall thickness of 0.7 mm is prepared, an adhesive is applied to the outer periphery, and a PFA tube 1c is wound around 380 mm.
It was heated and melt molded at ℃.

Next, the conductive polyimide tube 1d
After applying an adhesive to the inner surface of the core, the conductive polyimide tube 1d was inserted into the outer periphery of the cored bar 1a, and then heated and melted to bond the conductive polyimide tube 1d and the PFA tube 1c to be a PFA layer. Silver paste 1f was applied to both ends of a conductive polyimide tube 1d layer, which is a heat generating layer of this roller, in a ring shape so as to have a width of 5 mm, electrodes were formed, and a structure capable of conducting electricity was formed.

Next, the surface of this roller was covered with a PFA tube 1e having a thickness of 50 μm, and heated at 380 ° C. to be fused and adhered to obtain a heated roller 1.

The resistance temperature characteristic of the resistor of the conductive polyimide tube 1d has a negative characteristic that the electric resistance value decreases as the temperature rises as shown in Table 1 below.

[0031]

[Table 1]

In the pressure roller 2, a 3 mm thick silicone rubber layer 2b is formed on the outer periphery of a metal core 2a having an outer diameter of 30mm, and a release layer 2c made of a PFA tube is formed on the outer periphery. .

As shown in FIG. 3, the temperature sensor 3 installed on the surface of the heating roller 1 outputs the detected temperature to a control circuit 11 of the temperature control device. The heat generation temperature of the conductive polyimide tube 1d is controlled. The temperature sensor 3 is installed at an end of the heating roller 1 which is a non-sheet passing portion, as shown in FIG. This temperature control device uses a current sensor 12 provided in a current path for the conductive polyimide tube 1d to detect the conductive polyimide tube 1d.
In addition to detecting the current supplied to the heating roller 1, the temperature sensor 3 detects the surface temperature of the heating roller 1, and controls the operation of the current control circuit 13 and the motor 14 for controlling the rotation speed of the heating roller 1. .

Next, using NP6022 (trade name) manufactured by Canon Inc. as a copying machine, first, the heating roller 1 is incorporated into the NP6022, and the temperature sensor 3 as a temperature detection control means is connected to the end of the heating roller 1 ( 1 and 3 in the non-sheet passing portion), and while the power supply of 100 V is applied to the heating roller 1 by the temperature control device, up to 180 ° C. (roller center portion) which is a fixing temperature. When the temperature rise time was measured, it was 10 seconds, and the power consumption at this time was 1000 W. Next, when the postcard-size paper is continuously passed, the surface temperatures of the heat-passing portion and the non-sheet-passing portion of the heating roller 1 have characteristics as shown in FIG. 4, and a problematic image defect does not occur. Was.

The resistance temperature characteristics of the conductive polyimide tube 1d as the heating element of the heating roller 1 are as shown in FIG. That is, the temperature decreases as the surface temperature of the heating roller 1 increases. When the surface temperature of the paper passing portion decreases from the target temperature due to continuous paper passing of the printed matter, the resistance value increases, and the current flowing through the paper does not change corresponding to the constant temperature of the non-paper passing portion. Calorific value P, ie, P
= R · I ² (J) also increases because the current I is constant, and the temperature distribution of the heat generating roll 1 is maintained uniform between the non-sheet passing portion and the sheet passing portion of the paper.

Further, the conductive polyimide tube 1d has a low resistance current characteristic at a low temperature, so that the electromotive force at the time of cooling is small, and there is no need to provide a current limiting circuit in the power supply.

Embodiment 2 As shown in FIG. 6 and FIG. 7, as one of the pressure rollers 2 used in the fixing device of this embodiment, a heating layer made of a conductive seamless tube 2d made of polyimide is used as an insulating layer 2c. Disposed on the surface of the core 2a having an outer diameter of 34 mm through
After a silicone rubber layer 2e having a thickness of 3 mm is formed on the outer periphery, a PFA layer 2f as a surface layer is formed, and silver paste 2g is formed on both ends of the conductive seamless tube 2d in a ring shape so as to have a width of 5 mm. The electrode was formed by coating to form a structure capable of conducting electricity. In other respects, the heating roller 1 was prepared in the same manner as in the first embodiment, and an electronic copying machine (NP6
022), and as shown in FIG. 6, temperature sensors 3a and 3b as temperature detection control means are connected to the heating roller 1
After being installed at the surface end (non-sheet passing portion) and the center portion (sheet passing portion), respectively, the heating roller 1 is detected by the sensor 3a at the end.
The temperature of the pressure roller 2 was set to be controlled by the sensor 3b at the center, and the temperature rise time was measured while energizing. The result was 9 seconds, and the power consumption at this time was 1
It was 100W. Next, when a postcard-size sheet is continuously passed, the surface temperature of the heating roller 1 in the sheet passing portion and the non-sheet passing portion has characteristics as shown in FIG. 8, and a problematic image defect does not occur. Was.

Embodiment 3 As shown in FIGS. 9 and 10, the fixing device of this embodiment
In the combination of the heating roller 1 and the pressure roller 2 of the first embodiment,
An auxiliary heater roller 5 for heating the pressure roller 2 is provided. The auxiliary heater roller 5 has an outer peripheral surface of a metal core 5a covered with an insulating layer 5b made of PFA, and an outer peripheral surface of the insulating layer 5b covered with a conductive polyimide tube 5c having an outer diameter of 21 mm as a heating layer. Further, the outermost layer is covered with a fluororesin tube 5d made of PFA, and silver paste 5e is applied to both ends of the conductive polyimide tube 5c in a ring shape so as to have a width of 5 mm to form an electrode, and a structure capable of conducting electricity. Has been. The auxiliary heater roller 5 is a pressure roller 2
Is installed so as to heat the pressure roller 2. The three rollers 1 thus formed,
2 and 5 were incorporated in an electronic copying machine (NP6022), and temperature sensors 3a and 3b were installed at the surface end (non-sheet passing portion) and the center (sheet passing portion) of the heating roller 1 as in the second embodiment. When the heating time was measured while energizing the heating roller 1 by the sensor 3a at the end and the auxiliary heat roller 5 by the sensor 3b at the center, the heating time was 9 seconds. The power consumption at that time was 1100 W. Next, when continuous postcard size paper was passed,
The surface temperature of the heating roller 1 in the paper passing portion and the non-paper passing portion had characteristics as shown in FIG. 11, and no problematic image defects occurred.

COMPARATIVE EXAMPLE 1 As shown in FIG. 12, in the fixing device of Comparative Example 1, a temperature sensor 3 as a temperature detection control means is a heating roller 1
It is formed in the same manner as in the first embodiment, except that it is disposed at the center (paper passing portion) of the surface of. In this state, the temperature rise time was measured while energizing, and it was 9 seconds. Next, when the postcard-size paper is continuously passed, the temperature of the heating roller in the non-paper passing portion gradually rises, resulting in a characteristic as shown in FIG. 13 and a problem of exceeding 240 ° C. occurs. Was.

From this result, by setting the set position of the temperature sensor 3 as the temperature detection control means in the non-sheet passing portion of the heating roller 1, the heating at the time of continuously passing narrow paper such as a postcard size is performed. It has been found that excessive heating of the non-sheet passing portion on the surface of the roller 1 can be avoided. Further, by incorporating a heat generating layer into the pressure roller 2 or arranging the auxiliary heat roller 5 on the surface of the pressure roller 2 so as to circumscribe the temperature, the temperature can be controlled without lowering the temperature of the paper passing portion on the surface of the heat roller 1. However, it was found that a stable fixing device could be obtained.

Next, with respect to the fixing devices of the first to fourth embodiments, the fixing device is mounted in an electronic copying machine (NP6022).
When a pass-through durability test was performed on 10,000 PPC papers of four sizes each, there was no change in heat generation, and no image defects that would cause a problem even after the end of the durability were generated. The device was found to have good durability.

The conductive polyimide used for the heat generating layer in the fixing device of the present invention is a resin which is cured by heating, and this polyimide is converted into a polyimide by opening the imide ring of the precursor polyamic acid by heating or the like. Things. This polyamic acid is first used as a starting material, for example, pyromellitic dianhydride, 3,3 ′, 4,4
'-Biphenyltetracarboxylic dianhydride and 4,4'
-Phenylenediamine, 4,4'-biphenylenediamine and the like are each combined, and this equimolar is dissolved in a polar solvent such as N, N'-dimethylamide, N-methyl-2-pyrrolidone and the like. And a polycondensation reaction is carried out to obtain a liquid polymeric acid.

The conductivity imparting agent to be added to the polyimide is generally a conductive carbon black, such as acetylene black such as Denka Black (trade name, manufactured by Denki Kagaku Kogyo KK) and Ketjen Black ( AKZO
(Netherlands brand name) Oil furnace black, Toka Black (trade name from Tokai Carbon Co., Ltd.), Vulcan (brand name from Cabot (USA))
And one of these conductive carbon blacks.
About 5 to 50% by weight, preferably about 10 to 30% by weight, of the liquid polyamic acid is added. In addition, a conductive agent other than conductive carbon black such as metal powders such as silver, copper and nickel, metal oxides, graphite and carbon fiber may be used alone or in combination with carbon black. It is important that the resistance is set to 20Ω / □ or less. The amount of addition depends on the type of the conductivity-imparting agent, but if it is less than 5% by weight, the conductivity-imparting effect is often small, and if it exceeds 50% by weight, the viscosity of the polyamic acid solution becomes too high, and the solution casting method causes a tube. Cannot be created. Further, the thickness of the tube is preferably about 50 to 100 μm. This is because if the thickness is 50 μm or less, the tube strength becomes weak and the tube cannot withstand actual use. If the thickness exceeds 100 μm, the heat capacity becomes large, so that the temperature rise time becomes long and the power consumption becomes large. Absent.

The insulating layer of the heating roller 1 includes
Considering the heat resistance of the heating roller 1, PFA, PTFE
It is formed by coating a metal core 1a with a fluororesin such as (polytetrafluoroethylene), silicone rubber, silicone varnish, ceramic or the like. As a forming method, coating, heat molding by a press, or the like is appropriately applied. The metal core 1a used at this time is 3003 alloy, 5056 alloy, 6063 alloy, 707 alloy of aluminum.
Five alloys or the like are hot-extruded into a hollow cylindrical shape having a predetermined size, and finished by cutting to obtain a cored bar. In addition, a metal wire such as steel such as SKM material, stainless steel, and copper may be used. Further, when a tubular molded product such as ceramic or glass, which is an insulating material, is used as a core, it is not always necessary to coat the outer periphery of the core with an insulator.

The fluororesin, silicone rubber, fluororubber, etc., which form the insulating layer, may be filled, if necessary, with a filler,
Various additives such as a filler, a coloring agent, a heat-resistant agent, and a pigment can be added, and after molding, they may be polished to obtain dimensions and shapes.

In the case of silicone rubber, the formulation of the filler with respect to the insulating layer is not particularly limited as long as the insulating property is maintained. Usually, however, the reinforcing filler and the filler are added to 100 parts by weight of the base gum. About 10 to 300 parts by weight of the agent is added. As the reinforcing filler, wet silica or dry silica (fumed silica) is generally used. Here, the wet silica refers to a reinforcing silica made of silicon dioxide (SiO ₂ ). As a production method, a direct method of directly decomposing sodium silicate with sulfuric acid or a method of reacting sodium silicate with salts. There are various methods such as an indirect method in which silicate is formed and then decomposed with sulfuric acid or carbon dioxide gas.
Representative wet silicas include Nipsil VN3 (trade name, manufactured by Nippon Silica Industry Co., Ltd.) and Carplex CS-5.
(Trade name, manufactured by Shionogi Pharmaceutical Co., Ltd.), Star Sil S (trade name, manufactured by Kamishima Chemical Industry Co., Ltd.), Toksil US (trade name, manufactured by Tokuyama Corporation), Shilton R-2 (trade name, manufactured by Mizusawa Chemical Industry Co., Ltd.), Hisil223 (PPG (USA)
Product name), Ultrasil VN3 (Deguza, Germany)
And Vulkasil S (trade name, manufactured by Bayer AG, Germany). Grades having an average particle size of 30 μm or less, preferably 5 μm or less are used. Dry silica is a reinforcing silica made of silicon dioxide produced by the thermal decomposition method of silicon halide or the heat reduction of silica sand, and the air oxidation method of vaporized SiO and the thermal decomposition method of organic silicon compounds. , Aerosil 200 and Aerosil R972
(Trade name of Nippon Aerosil Co., Ltd.), Cab-O-Sil
MS-5 (trade name, manufactured by Cabot Corporation (USA)) and Leoloseal QS102 (trade name, manufactured by Tokuyama Corporation) are exemplified. In the present invention, wet silica and dry silica may be used in combination as needed. Further, a lubricant (wetter) may be added for the purpose of preventing secondary bonds due to the activity of the silica surface. Examples of the lubricant include silicone resins, alkoxysilanes and siloxanes, hydroxysilanes and siloxanes, and silazanes. , Organic acid esters, polyhydric alcohols and the like.

The bulking filler is a component necessary for maintaining insulating properties and mechanical properties of rubber, that is, properties that are indispensable to function as an insulating layer, such as physical strength, rubber hardness, and compression set. Calcium, quartz powder, diatomaceous earth, zirconium silicate, clay (aluminum silicate), talc (hydrated magnesium silicate), wollastonite (calcium metasilicate), titanium oxide, zinc oxide, magnesium oxide, alumina (oxide Aluminum), chromium oxide, red iron oxide, aluminum sulfate, barium sulfate, lithopone, molybdenum disulfide, mica (mica powder) and the like. Further, a heat resistant agent such as cerium oxide may be added.

In general, a heating roller made of silicone rubber is often supplied in a reddish color, and in this case, reddish is generally used as a coloring agent. As the type of bengara, a bengara for rubber specified in SRIS1108 (Japanese Rubber Association Standard) can be applied, and when it is necessary to pay attention to the orientation in the rubber during processing, Bayferox 130M (Bayer Corporation) (Germany brand name) and a spherical grade having an average particle size of 0.3 μm or less,
What is necessary is just to add about 2 weight%.

The vulcanization system is a peroxide vulcanization type using a peroxide such as dicumyl peroxide or 2,5-dimethyl-25-di- (tert-butylperoxy) -hexane. It may be an addition type composed of a vinyl group-containing organopolysiloxane and a hydrogenene polysiloxane, or a condensation type.

For the adhesion between the insulating layer made of silicone rubber and the heat generating layer made of conductive polyimide tube, an addition type silicone rubber made of a vinyl group-containing organopolysiloxane and a hydrogendiene polysiloxane can be used. DY on the inner surface of the polyimide tube
It is necessary to apply a primer composed of a silane coupling agent or a titanium coupling agent such as 39-067 (trade name, manufactured by Dow Corning Toray Silicone Co., Ltd.).

When an addition type silicone rubber composition containing an adhesion-imparting agent is used for adhesion between the insulating layer and the conductive polyimide tube, the adhesion-imparting agent is disclosed in Japanese Patent Publication No. Hei 7-53432 or Japanese Patent Publication No. Sho 59-53. An organic silicon compound containing an epoxy group as described in JP-A-5219 is exemplified. In this case, it is not always necessary to apply a primer to the inner surface of the polyimide tube. Also, attach a conductive polyimide tube to the outer periphery of the core,
The addition type silicone rubber composition containing the adhesion-imparting agent may be poured into the gap between the cored bar and the tube, and the formation of the insulating layer and the bonding with the heat generating layer formed of the polyimide tube may be integrally formed in one step. At this time, if an addition type silicone rubber containing no adhesion imparting agent is used, it can be dealt with by applying a primer on the inner surface of the polyimide tube in advance.

In the fixing device of the present invention, a silver paste is generally used as an electrode formed on the surface of the conductive polyimide tube of the roller having the heat generating layer, and is available from Syntron K-3424 (a product of Shinto Paint Co., Ltd.). Name),
Examples include Unimec H9100 (trade name, manufactured by Namics Corporation), Alzelite VH-13 (trade name, manufactured by Tamura Kaken Co., Ltd.), and PS-769 (Tokuriki Chemical Laboratory Co., Ltd.).

For connection between the electrode and the power supply, a high-temperature solder is preferably used. Examples thereof include S-256 (trade name of Senju Metal Co., Ltd.) and T-14 (trade name of Nihon Almit Co., Ltd.). Silver containing solder (melting point 221 ° C) or K
Pure tin solder (melting point: 232 ° C.) such as R-19 (trade name, manufactured by Nippon Almit Co., Ltd.); Examples thereof include tin-antimony solder (melting point: 240 ° C.) such as 240 (trade name, manufactured by Tamura Kaken Co., Ltd.). If necessary, Solderlite Y-32V (trade name, manufactured by Tamura Kaken Co., Ltd.) and FSR
-086 (trade name, manufactured by Fuji Alloy Industry Co., Ltd.), RMA-
8 (trade name, manufactured by Senju Metal Co., Ltd.).

The adhesion between the core metal and the insulating layer made of silicone rubber is performed, for example, in the case of addition-type silicone rubber, using primer No. Stronger adhesion by using a primer for additional silicone rubber such as 101A / B (trade name of Shin-Etsu Chemical Co., Ltd.) or DY39-051A / B (trade name of Dow Corning Silicone Co., Ltd.) Can be obtained.

The fixing device of the present invention is not limited to the above embodiment, but can be changed as required.

[0056]

As described above, in the fixing device of the present invention, the heating element of the heating roller is formed of a non-metallic heating element whose electric resistance value decreases as the temperature rises, and the temperature detection control for detecting and controlling the temperature is performed. By disposing the temperature sensor related to the means at the non-paper passing portion of the heating roller, it is possible to avoid excessive temperature rise of the non-paper passing portion on the heating roller surface when continuously feeding narrow paper, and cooling The effect is that the electromotive force at the time is small and there is no need to provide a current limiting circuit in the power supply. Further, by incorporating a heat generating layer in the pressure roller or arranging an auxiliary heat roller on the surface of the pressure roller, it is possible to avoid the temperature drop on the surface of the heat roller during continuous paper feeding. .

More specifically, according to the fixing device of the first aspect, the electromotive force during cooling can be reduced by using the non-metallic heating element, and the paper passing portion of the heating roller at the time of continuous paper passing is required. The temperature of the surface of the heating roller can be prevented from dropping, and the excessive temperature rise of the non-sheet passing portion on the surface of the heating roller when continuously feeding narrow paper can be avoided. By installing a temperature detection control unit such as a temperature sensor in the non-sheet passing portion and controlling the temperature, it is possible to avoid an excessive temperature rise in the non-sheet passing portion.

According to the fixing device of the second aspect, the use of the non-metallic heating element makes it possible to reduce the electromotive force at the time of cooling, and to reduce the electromotive force at the time of continuous paper feeding. A temperature sensor that can avoid temperature drop, avoid excessive temperature rise in the non-paper passing area on the surface of the heating roller when continuously feeding narrow paper, and a temperature sensor disposed on the outer periphery of the heating roller By installing a temperature detecting means such as in the non-paper passing area and controlling the temperature, it is possible to avoid excessive temperature rise in the non-paper passing area, and to use other temperature sensors in the paper passing area on the outer periphery of the heating roller. By setting the temperature detection control means, and controlling the temperature of the pressure roller having the heat generating layer by the temperature detection control means disposed in the paper passing section, it is possible to avoid an excessive temperature rise in the non-paper passing section. be able to.

According to the fixing device of the third aspect, the use of the non-metallic heating element makes it possible to reduce the electromotive force at the time of cooling and to reduce the surface area of the paper passing portion of the heating roller during continuous paper passing. A temperature sensor that can avoid temperature drop, avoid excessive temperature rise in the non-paper passing area on the surface of the heating roller when continuously feeding narrow paper, and a temperature sensor disposed on the outer periphery of the heating roller By installing a temperature detecting means such as in the non-paper passing area and controlling the temperature, it is possible to avoid excessive temperature rise in the non-paper passing area, and to use other temperature sensors in the paper passing area on the outer periphery of the heating roller. The temperature control of the auxiliary heat roller that heats the pressure roller is performed by the temperature detection control unit disposed in the paper passing unit by installing the temperature detection control unit of Can be avoided.

Further, according to the fixing device of the fourth aspect, the temperature control of the heating roller can be more appropriately performed.

According to the fixing device of the fifth aspect, the temperature of the heating roller can be controlled more appropriately.

According to the fixing device of the sixth aspect, the heat generating layer can be easily formed, and the temperature can be properly controlled.

Further, according to the fixing device of the present invention, it is possible to heat the conductive tube while freely controlling the amount of heat generated.

By operating the temperature control device of the present invention according to the ninth aspect according to the temperature control method of the eighth aspect, the surface temperature of the heating roller can be reliably and uniformly maintained.

[Brief description of the drawings]

FIG. 1 is a front view showing a first embodiment of the present invention.

FIG. 2 is a right side view of FIG.

FIG. 3 is a front view showing an embodiment of the temperature control device of the present invention.

FIG. 4 is a characteristic diagram illustrating a relationship between the number of sheets passed and the roller surface temperature according to the first embodiment.

FIG. 5 is a characteristic diagram showing resistance-temperature characteristics of the nonmetallic heating element of the present invention.

FIG. 6 is a front view showing a second embodiment of the present invention.

FIG. 7 is a right side view of FIG.

FIG. 8 is a characteristic diagram showing a relationship between the number of sheets passed and the roller surface temperature according to the second embodiment.

FIG. 9 is a front view showing a third embodiment of the present invention.

FIG. 10 is a right side view of FIG. 9;

FIG. 11 is a characteristic diagram showing the relationship between the number of sheets passed and the roller surface temperature according to the third embodiment.

FIG. 12 is a front view showing Comparative Example 1;

FIG. 13 is a characteristic diagram showing the relationship between the number of sheets passed and the roller surface temperature in Comparative Example 1.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 heating roller 2 pressure roller 3 temperature sensor 5 auxiliary heat roller 11 control circuit 12 current sensor 13 current control circuit

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) H05B 3/00 335 H05B 3/00 335 3/14 3/14 E (72) Inventor Norio Goto 3 Horikiri, Katsushika-ku, Tokyo Chome 30-1 Inside Arai Seisakusho Co., Ltd. (72) Inventor Eiji Oki 3-30-1, Horikiri, Katsushika-ku, Tokyo F-Term inside Arai Seisakusho Co., Ltd. 2H033 AA03 AA21 AA31 BA25 BA32 BB01 BB18 BB30 CA07 CA51 3J103 AA02 AA15 AA51 BA02 FA01 FA20 GA02 GA52 GA57 GA58 GA66 HA04 HA05 HA20 HA22 HA37 HA43 HA46 HA51 3K058 AA12 AA42 AA87 BA18 CA04 CA05 CA12 CA46 CA63 CA91 CB10 CB24 CE03 CE13 CE17 DA04 GA06 3K09BQC Q18 QC10 RD07 RD16 RD28 RD34 TT35 UA06 UA17 VV25

Claims (9)

[Claims] 1. A fixing device comprising a heating roller and a pressure roller for fixing a transferred image to transfer paper by heat, and a temperature detection control means for detecting and controlling a temperature on the heating roller. The heating element is formed of a non-metallic heating element whose electric resistance value decreases as the temperature rises, and the temperature detection control means is disposed in a non-sheet passing portion on the outer periphery of the heating roller. Fixing device. 2. A heating roller for fixing a transferred image to transfer paper by heat, a pressure roller having a heating element,
In a fixing device having a temperature detection control means for detecting and controlling a temperature on a heating roller, the heating elements of the heating roller and the pressure roller are each formed of a non-metallic heating element whose electric resistance value decreases as the temperature rises. The temperature detection control means on the heating roller is disposed in a non-sheet passing portion on the outer periphery of the heating roller, and another temperature control detection means is disposed in a paper passing portion on the outer periphery of the heating roller. Wherein the temperature of the pressure roller is controlled by temperature detection control means disposed in the paper passing portion. 3. A fixing device comprising a heating roller and a pressure roller for fixing a transferred image to transfer paper by heat, and a temperature detection control means for detecting and controlling a temperature on the heating roller. The heating element is formed of a non-metallic heating element whose electric resistance value decreases as the temperature rises, an auxiliary heat roller for heating the pressure roller is provided, and the temperature detection on the heating roller is performed. A control means is provided in a non-paper passing portion on the outer periphery of the heating roller, and another temperature detection control means is provided in a paper passing portion on the outer periphery of the heating roller, and is provided in the paper passing portion. A fixing device, wherein the temperature of an auxiliary heat roller disposed on a pressure roller is controlled by a temperature detecting means. 4. The heating element according to claim 1, wherein the non-metallic heating element of the heating roller is formed in a layer shape on an outer or inner circumference of a core bar having an insulating layer. 3. The fixing device according to claim 1. 5. The fixing device according to claim 2, wherein the non-metallic heating element of the pressure roller is formed in a layer shape on an outer or inner circumference of a core having an insulating layer. 6. The fixing device according to claim 1, wherein the heat generating layer is a conductive tube made of polyimide or polyamide imide. 7. The conductive tube has a surface resistance of 20Ω.
7. The fixing device according to claim 6, wherein the fixing device is a seamless tube of // or less. 8. A fixing device comprising: a heating roller and a pressure roller for fixing a transferred image to transfer paper by heat; and a temperature detection control unit for detecting and controlling a temperature on the heating roller. The heating element of the roller is formed of a non-metallic heating element whose electric resistance value decreases as the temperature rises, and the temperature detection control means is disposed in a non-sheet passing portion on the outer periphery of the heating roller. In the temperature control method for controlling the temperature of the device, the temperature of the heating roller is detected by the temperature detection control unit, and at the same time, the value of the current supplied to the non-metallic heating element is detected by a current sensor. A method for controlling the temperature of a fixing device, comprising controlling the state of energization of a body so as to maintain the surface temperature of a heating roller uniform. 9. A fixing device comprising: a heating roller and a pressure roller for fixing a transferred image to transfer paper by heat; and a temperature detection control unit for detecting and controlling a temperature on the heating roller. The heating element of the roller is formed of a non-metallic heating element whose electric resistance value decreases as the temperature rises, and the temperature detection control means is disposed in a non-sheet passing portion on the outer periphery of the heating roller. A temperature control device for controlling the temperature of the apparatus, wherein the temperature detection control means for detecting the temperature of the heating roller, a current sensor for detecting a current value supplied to the non-metallic heating element, and the non-metallic heating element A current control circuit for controlling the state of current supply to the heating roller, and maintaining the surface temperature of the heating roller uniformly according to the detected temperature of the heating roller and the value of the current supplied to the non-metallic heating element. And a control circuit for controlling the temperature of the fixing device.