JPH1048986A - Fixing roller and method of controlling temperature of fixing roller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently heat a fixing nip part with low power consumption by forming heating elements divided into a line or a plurality of lines in the axis longitudinal direction of a roller base material by thin films of prescribed thickness. SOLUTION: Heating elements (EL) are so formed as being divided into a line or a plurality of lines in the axis longitudinal direction of a roller base material by thin films of thickness 1∼150μm. A backup roller 9 is arranged opposite to a fixing roller 20. Respective fixing roller 20 and backup roller 9 are rotated in the direction shown by an arrow and a transcription paper sheet S to be fixed is fed in the direction shown by an arrow 21 so as to be fixed at a nip part in this process. In this case, brushes provided to respective immobile members are brought in contact with respective electrodes H1∼H5. Power supply is connected across the brushes and the common electrodes and the current is applied across the appropriate terminals and the common electrodes via the brushes so that the heating element can be heated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing roller for heating and pressure-fixing an unfixed transfer toner image transferred to transfer paper in an image forming apparatus employing an electrostatic developing system, an electrostatic transfer system or the like. The present invention relates to a method of manufacturing the fixing roller, a method of using the fixing roller, and a temperature control device of the fixing roller.

[0002]

2. Description of the Related Art There has been known a fixing roller used as a pair with a backup roller, in which a heating element is formed on the entire surface of a roller-shaped base material (Japanese Patent Laid-Open No. Hei 1-1990).
JP-A-161389, JP-A-2-19879, JP-A-3-201385, JP-A-1-164982
And Japanese Patent Application Laid-Open No. 6-87183. As a technique for reducing the heat capacity, Japanese Patent Application Laid-Open No.
Japanese Patent Application Laid-Open Nos. 1648661, 60-131784 and 61-262774. The heating element in the conventional fixing roller is NiCr
Films and sintered bodies of carbon, SiC, etc. are used.
Further, a release agent film is formed with a silicone-based or fluororesin-based toner having a thickness of 300 to 500 μm.

[0003]

In the above prior art, the entire fixing roller is heated to 180 ° C. to 200 ° C. to fix the toner.
Heat capacity is relatively large due to the thickness of μm, and actually 1 kW
Even when the above-described heating power is used and a low-power method is adopted, a roller of A4 size to A3 size requires 0.8 kW, and a maximum power of 1.2 kW.

Accordingly, an object of the present invention is to provide a fixing roller and a method of controlling the temperature of the fixing roller which can efficiently heat the fixing nip portion with lower power consumption.

[0005]

The present invention has the following configuration to achieve the above object. (1) In a fixing roller in which a heating element capable of generating Joule heat is formed on a surface portion of a substantially insulated roller-shaped substrate, the heating element is formed by a thin film having a thickness of 1 to 150 μm. And formed in one or a plurality of lines in the longitudinal direction of the shaft (claim 1).

(2) In the fixing roller according to (1),
The roller-shaped substrate was constituted by a hollow roller made of ceramics or glass (claim 2).

(3) In the fixing roller according to (1) or (2), an aluminum or aluminum alloy material is used as a material of the roller-shaped base material, and a void is formed inside the vicinity of the outer peripheral surface of the roller-shaped base material. (Claim 3).

(4) In the fixing roller according to (1) or (2), aluminum or an aluminum alloy material is used as a material of the roller-shaped base material, and the heating element is provided near an outer peripheral surface of the roller-shaped base material. A void portion was formed at a position inside the inner space (claim 4).

(5) (1), (2), (3) or (4)
In the fixing roller described above, the heating element is made of a thin film formed by composite plating of nickel and a fluororesin on a conductive layer formed by electroless metal plating or vacuum evaporation on the surface of the roller-shaped substrate. (Claim 5).

(6) A temperature control means for a fixing roller having a heating element capable of generating Joule heat formed on a surface portion of a substantially insulated roller-shaped substrate, wherein the heating element is provided on a shaft of the roller-shaped substrate. When performing a fixing operation by combining a fixing roller formed by dividing into a plurality of lines in the longitudinal direction with a backup roller, the heating of each of the heating elements is performed more in a rotational direction of the fixing roller than in a nip portion with the backup roller. Preheating is performed so that the temperature is sequentially increased from the upstream side in the rotation direction of the fixing roller, so that an optimum fixing temperature is obtained in the nip portion.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION

(1) Examples of the invention described in claim 1, claim 2, and claim 5 FIG. 2 shows a structure of a roller serving as a basis of the fixing roller. The central portion of this roller is made of a roller-shaped base material 1 and is made of a stainless steel such as SUS304 or the like which is hardly deformed and processed into a cylindrical shape. An insulating and heat-insulating material is coated and joined to the peripheral surface of the roller-shaped substrate 1. FIG. 2 shows a state in which an insulating heat-resistant material layer 3 is formed in a cylindrical shape via a bonding material 2 made of polyimide or low-melting glass. Ceramics can be used as a material for forming the insulating heat-resistant material layer 3. Alternatively, steatite or aluminum oxide can be used.

When a roller having the structure shown in FIG. 2 is formed, a belt-like shape is then formed on the entire surface of the insulating heat-resistant material layer 3 or on the peripheral surface along the longitudinal direction of the roller-shaped substrate 1. Ni,
A metal layer made of Au, Pt, or the like is formed by electroless metal plating or vacuum evaporation. FIG. 3 shows a metal layer 4 in a strip shape.
An example in which is formed. The width w, thickness t, distance between bands p, and the like of the band-shaped metal layer 4 are determined in relation to a heating element formed on the metal layer 4. For example, the thickness t is 500 to
Approximately 2,000 mm. After the steps up to this point, the process proceeds with either the case 1 or the case 2 described below.

A. An electrodeposited film of Ni or Cr is formed on the surface of the metal layer 4 of the fixing roller by the process of the case 1 by using the metal layer as an electrode. In the example shown in FIG. 4, an example is shown in which the metal layer 4 is formed in a band shape at a constant pitch on the peripheral surface of the insulating heat-resistant material layer 3, and the electrodeposition film 5 is formed on the metal layer 4. The metal layer 4 is not strip-shaped, but the insulating heat-resistant material layer 3
In the case where the metal layer is formed on the entire peripheral surface, a metal layer is formed in a stripe shape on the insulating heat-resistant material layer according to the metal layer 4 of FIG. The thickness of the electrodeposition film 5 can be selected from an appropriate value among 1 to 30 μm, preferably 5 to 10 μm. Next, Ni-PTFE (polytetrafluoroethylene) is used to cover the metal layer 4 and the electrodeposition film 5 and to form a smooth peripheral surface so as to enhance the peeling performance of the toner at the time of fixing. ) Is formed on the surface, or a release material layer 6 made of a silicon-based or fluororesin-based material is formed.
Thus, the fixing roller 8 is configured.

The electrodeposition film 5 is exposed at the axial end surface of the fixing roller 8. The electrodeposition film 5 is a heating element for generating Joule heat. To function as a fixing roller, the exposed portion is used as an electrode to supply electricity to the heating element. But,
Since the electrodeposition film 5 itself is very small, there is a possibility that the contact of the brush as the current applying means during rotation of the fixing roller may be incomplete. Therefore, in this example, the electrode 7 having a size sufficient for contact with the brush is formed.

As shown in FIG. 6, the fixing roller 6 thus manufactured is installed so as to face the backup roller 9 for pressurization. An energizing brush 10 is located in a nip portion between the backup roller 9 and the fixing roller 8 and in a region where the electrode 7 passes. When the electrodeposition film 5 is located at the nip portion, a current flows from the brush 10 to the electrodeposition film 5, the electrodeposition film 5 generates Joule heat, and the unfixed toner T on the transfer sheet S is fixed. This becomes the fixing toner T ′.

B. Fixing Roller by Process of Case 2 As shown in FIG. 3, after the metal layer 4 is formed on the outer peripheral surface of the insulating heat-resistant material layer 3, as shown in FIG. By performing composite plating using PTFE, an electrodeposition film 11 having a thickness of 1 to 150 μm, preferably 10 to 50 μm is formed. Nimflon-based and metaflon-based materials (trade name: Uemura Kogyo Co., Ltd.)
Can be used.

The electrodeposited film 11 is obtained by using an electron microscope to
As shown in FIG. 10, which schematically shows a photograph magnified 0000 times, a fused layer in which a large amount of PTFE particles (indicated by black circles) 140 are dispersed on Ni ground is the same in appearance and cross section. It has such an appearance. The electrodeposition film 11 constitutes a heating element. Electric resistance depends on film thickness, but width 2m × 22
0 mm x 10 μm thickness and about 5 to 10Ω
It can be adjusted by changing the mixing ratio of PTFE and PTFE.
In addition, the initial underlayer Ni film (500 ° is 1-2
μm), the resistance can be further reduced.

In the case shown in FIG. 3, when the thickness t 'of the electrodeposition film 11 is 10 μm, the distance p ′ between the adjacent electrodeposition films 11 is preferably within 5 to 10 μm.

Next, at 250 to 400 ° C., preferably 3
A heat treatment is performed at a temperature of 00 to 350 ° C., and a wiping process is further performed. By this wiping process, Ni is formed in the gap between the adjacent strip-shaped electrodeposition films 11.
And PTFE fine particles are embedded. Embedded Ni
And the fine particle portion of PTFE are indicated by reference numeral 12.

The fixing roller 14 thus manufactured is subjected to fixing in combination with the backup roller 9 in accordance with the configuration shown in FIG. Although not shown in FIG. 9, an electrode is provided at the axial end of the fixing roller 14 in accordance with the electrode 7 shown in FIG. 6 to improve the contact with the brush. Shall be.

As in this example, a heating element having a function of peeling off the toner is provided by a Ni / PTFE composite plating portion of a thin film formed by electroless and electrodeposition plating of Ni and a fluorine resin. As described above, when the electrodeposition film 11 is formed by using the Ni / PTFE-based material, the electrodeposition film 11 has a function as a heating element and a toner peeling function, and has a thickness of 1 to 150 μm, preferably 10 to 150 μm. Since the thickness is 50 μm, the heat capacity is smaller than the conventional 300-500 μm release film of silicon or fluorine resin, so that the heat transfer is excellent, and the nip portion can be heated in a state close to the on-demand heating. The surface to be coated is a state in which fine particles of PTFE (0.5 to 10 μm) are dispersed and Ni
Since it is held in the vicinity, the heating energy is directly transmitted to the toner, fixing the toner having a melting point of 180 to 200 ° C., and the toner is separated from the fine particle interface of PTFE, and is set up on the fixing roller. Absent. Further, by using a line heater in which the heating element is formed in a line shape, it is possible to raise the temperature in the nip portion at an appropriate temperature in real time. Further, since the PTFE is held between the Ni particles, the thermal conductivity is good, the efficiency is good, and the wear resistance is dramatically improved.

Example 2 The roller-shaped substrate 1 described with reference to FIG. 2 in Example 1 is cylindrical, that is, solid (not hollow).
However, as the material of the roller-shaped substrate 1, for example, a ceramic or a low-expansion heat-resistant glass-based material is used.
It can be configured as a hollow roller. Except that the roller-shaped substrate 1 has a hollow structure, a conductive layer is formed by electroless metal plating or a vacuum deposition method in the same manner as described in Example 1, and a composite of nickel and a fluororesin is further formed. An electrodeposition film (heating element) composed of a thin film is formed by plating. As described above, the fixing roller using the hollow body is characterized in that the hollow portion has a heat insulating function, and as a characteristic of ceramics and glass materials, it has heat resistance, insulation, and heat insulation properties. Further, FIG.
It is not necessary to form the insulating heat-resistant material layer 3 as shown in FIG.

When the electrodeposition film 5, the electrodeposition film 11 or the like as the heating element is formed as a thin film having a thickness of 5 to 30 μm and is constituted as a so-called line heater divided into a plurality of lines on the peripheral surface of the roller, a backup roller is provided. 9 at the nip portion and locally heat it by intensive heating (180 to 20).
0 ° C.), and there is no extra heat and heat radiation in other parts, so that heat radiation and dispersion are small compared to the conventional whole heating, and a low power consumption fixing roller can be provided. Further, it is possible to suppress a rise in the temperature inside the image forming apparatus. Therefore, a cooling fan is not required. As a result, it is possible to provide a fixing roller capable of achieving high efficiency and high performance as a fixing performance and saving space as an image forming apparatus. Furthermore, since the temperature can be raised with high efficiency in the nip portion, it is possible to always control the temperature to the optimum temperature.

(2) Example of the invention described in claim 3 In FIG. 11, the roller substrate 1 is made of aluminum or an aluminum alloy. The peripheral surface of the roller substrate 1 is oxidized by applying an anodic oxidation method, as shown in FIG.
As shown by reference numeral 15, the anodic oxide film (β-Al ₂ O ₃ ) has a height (thickness) of 0.1 to 100 μm, preferably 1 to 50 μm.
Crystallize into a column of about μm. This β-crystallized
FIG. 13 schematically shows an enlarged view of Al ₂ O ₃ . This anodic oxide film is porous, insulating, heat resistant,
Excellent rigidity. In FIG. 13, each columnar portion has a shape close to a hexagon, and is 100 to 5,0 in the central axis direction.
A hole 16 of 00 ° is formed. The hole diameter, the hole depth, and the like are obtained under appropriate conditions depending on the electrolytic solution and the voltage.

The hole 16 is subjected to an acid treatment or a treatment in boiling water (an alkali or an acid can be added) to grow Al ₂ O ₃ and perform a surface sealing treatment. As a result of this sealing process, the holes 16 of each columnar portion are sealed as voids 16a inside the vicinity of the outer peripheral surface of the roller-shaped substrate as shown in FIG. This is heat-treated at a temperature of 300 to 400 ° C. to obtain β-Al
Stabilize as ₂ O ₃ . In FIG. 14, the lower part of the gap 16 is the Al / β-A
It forms a hybrid of l ₂ O ₃ .

The roller-shaped substrate 1 thus constructed
An electrodeposition film similar to the electrodeposition film 5 or the electrodeposition film 11 described in the first embodiment is formed on the outer peripheral surface portion of the above to form a fixing roller. FIG. 15 shows an example of this. A gap 16a is formed in the vicinity of the outer peripheral surface of the roller-shaped base material 1 made of Al, and the metal layer 4 and the electrode are formed in accordance with the contents described in FIGS. The fixing film 18 is formed by forming the deposition film 5 and the release material layer 6.
In addition, the fixing roller can be formed by the metal layer 4, the electrodeposition film 11, the fine particles 12 of Ni and PTFE, and the like according to the contents described in FIGS.

In this example, since the gap 16a is interposed between the heating element and the aluminum material, the gap 16a
Has a heat insulating effect, has low heat dissipation, and requires low power. In addition, by forming the electrodeposition film 11 of a thin film of Ni / PTFE, a heating element and a toner peeling layer can be provided together, and fixing can be performed for A4 to A3 sizes with low power of about 200 to 300 W. Becomes

(3) Example of the invention described in claim 4 The forms of the electrodeposited films 5 and 11 as the heating elements applied in Examples 1, 2 and 3 are formed by dividing the roller-shaped base material 1 into one line or a plurality of lines in the axial longitudinal direction. In the case of a plurality of lines, a stripe shape is formed.
In the case of one line, the entire peripheral surface can be covered with the thin film, or the entire peripheral surface can be covered with the thin film while leaving a slight gap. The heating elements such as the electrodeposited film 5 and the electrodeposited film 11 are 1 to 150 μm (preferably 5 μm).
When a thin film having a thickness of about 30 μm is used, the heat capacity is small, and the Ni / PTFE electrodeposited thin film can have both a heat generation function and a peeling function. Even if the entire surface of the roller is heated so as to cover the entire peripheral surface, the power consumption is small, the surface temperature of 180 to 200 ° C. can be maintained with the power consumption of about 500 W, and sufficient fixing performance can be obtained. The same can be said for the configuration in which the electrodeposition film 5 is covered with the release agent layer 6 as shown in FIG. The electrodeposited film of Ni / PTFE is made of NTC.
Since it has thermistor characteristics, the constant current power supply heating mechanism shows good results.

Further, in the example in which the entire surface of the fixing roller of the electrodeposition film 11 is applied, high-speed fixing (50 to 100 copies / minute) is possible by setting the entire fixing roller to an appropriate temperature. Further, the surface irregularities are PTFE fine particles (0.5 to 10 μm).
m) and heat treatment after formation (200 to 400 °).
C), and further wiping, the surface property becomes R
max can be in the range of about 0.3 to 1.5.
Although it depends on the toner particles, Rmax is 0.3 to 1.
0 is desirable.

(4) Example of the invention described in claim 6 Since the heating element of the fixing roller of the present invention is divided into a plurality of lines, it is possible to further control the power by applying a current when necessary. From this, it is possible to heat in a stepwise manner by controlling the electric power at the time of rotation near the nip portion depending on the level of the room temperature, and it is possible to always maintain the optimum temperature in the nip portion. Also, depending on the temperature and moisture absorption of the transfer paper, the stepwise heating method enables fixing under appropriate conditions. An example will be described below.

Example 5 The heating elements such as the electrodeposition film 5 and the electrodeposition film 11 as the heating elements described in the above Examples 1 and 2 are collectively shown as a heating element of the fixing roller 20 in FIGS. did. The backup roller 9 is arranged to face the fixing roller 20. The fixing roller 20 and the backup roller 9 rotate in the direction of the arrow to send out the transfer paper S to be fixed in the direction of the arrow 21 and fix the toner at the nip on this assumption. 1 and 16, the electrode of the heating element 19 located at the nip portion is denoted by reference numeral H1, and hereinafter, the reference numeral H2 indicates the electrode order of the heating element located on the upstream side in the rotation direction of the fixing roller 20 indicated by the arrow. ,
H3, H4, H5...

At this time, the electrodes H1, H2, H3, H
4 and H5 each have a brush 22 provided on a stationary member.
Are in contact. Electrode H at a position facing the nip
The terminal of the brush 22 that is in contact with the electrode 1 is EL1, the terminal of the brush 22 that is in contact with the electrode H2 adjacent to the upstream is EL2, and similarly, the terminals EL3, EL4,
EL5. At the end in the axial direction of the fixing roller 20 opposite to the side where the brushes 22 are provided, a ring-shaped common electrode 23 conducts the respective heating elements 19 in common as shown in FIG. And is in contact with a brush (not shown). If a power supply 24 is connected between the brush 22 and the common electrode 23, a current is applied between the corresponding terminals EL1 to EL5 and the common electrode 23 via the brush 22 to cause the heating element to generate heat. Can be. further,
If different currents are individually applied to the terminals EL1 to EL5, the heating elements corresponding to the electrodes in contact with the brushes 22 can be individually heated.

Then, for example, the applied current to the electrode H5 <
Current applied to electrode H4 <current applied to electrode H3 <electrode H
If the current is applied so that the applied current to the electrode 2 is smaller than the applied current to the electrode H1, the heating element located upstream of the nip is preheated so as to be heated as it approaches the nip, An optimum fixing temperature can be obtained in the nip portion. For example, focusing on the electrode H1, this electrode H1 is the electrode H5 in FIGS.
When the electrode H1 is moved to the position of the electrode H4, a current is applied from the terminal EL5 to the electrode H5 via the brush 22 to start preheating.
L4 applies a larger current and preheats to a higher temperature. Hereinafter, in the same manner, the preheating is successively performed to a higher temperature, and when the electrode H1 reaches the position facing the nip portion shown in FIG. This is applied to H1, so that an optimum fixing temperature can be obtained in the nip portion.

In FIG. 17, the optimum fixing temperature at the nip portion is indicated by t _m (= 180 to 200 ° C.), and the heating elements which generate heat by the brushes 22 corresponding to the terminals EL1 to EL5 are (EL1) and (EL1). EL2), (EL3),
As shown in (EL4) and (EL5), the voltages applied to these terminals are 3v, 3.5v, 4v, 4.5v, 5v
As a result, the temperature of these heating elements becomes (EL5) <
(EL4) <(EL3) <(EL2) <(EL1), and the heating element (EL) located in the nip portion
By performing on / off control of the current so that the temperature of 1) is maintained at the fixing temperature t _m , the temperature of the heating element in the nip portion can always be maintained at the optimum fixing temperature t _m .

Example 6 Next, another temperature control will be described. In this example, in FIG.
Eight are provided corresponding to 1 to H8. Similarly to the above-mentioned example, the terminals corresponding to these electrodes are EL1 to EL8. Further, in FIG. 19, the optimum fixing temperature of the heating element at the nip portion and t _m, a heating element is caused to generate heat by the brush 22 corresponding to the terminals EL1~EL8 (EL1)
To (EL8): a. In the case where the room temperature is low and the humidity is high and the transfer paper S contains a large amount of moisture, pre-heating is performed from the eight heating elements upstream from the nip by the temperature gradient shown by When the water content of the paper 8 is low, the paper 8 is preheated from the nip portion up to six upstream heating elements by a temperature gradient indicated by c. When the room temperature is high and the humidity is low and the moisture content of the transfer paper 8 is small, the temperature gradient shown by
Preheating is performed from the heating element on the upstream side up to the number. In these cases, the temperature gradient is gentle in the order of >>. Thus, by changing the number of heating elements to be preheated and the temperature gradient according to the temperature and humidity conditions, more appropriate fixing temperature control can be performed.

Example 7 A specific example of temperature control will be described with reference to FIG. In FIG. 20, one terminal of the power supply 24 and each brush 22 are individually connected so that a different current can be applied to each brush. The other terminal of the power supply 24 and the common electrode 23 are connected via a conductive wire and a brush. The power supply 24 and the switch group 25 are individually connected to switches so that each brush can be turned on and off. On the other hand, the temperature control device 26 includes a CPU 27 and a RAM.
28, a ROM 29, a shift register 30, an I / O 31, and the like. Further, a temperature sensor 32 for detecting the room temperature of the fixing roller 20 and a humidity sensor 33 for detecting humidity are provided, and the detection information of these sensors is taken into the CPU 27 via the I / O 31. Has become. The CPU 27 receives the detection information from the temperature sensor 32 and the humidity sensor 33, and
9, information is exchanged with a RAM 28 which stores control information shown in advance, and information is exchanged with a shift register 30.
Appropriate preheating conditions are set, and the switch group 25 is controlled. By the operation of such a temperature control device, the temperature control as in Examples 5 and 6 is executed.

As described above, a different current can be applied to each of the heating elements divided into a plurality of lines.
Achieve the optimum temperature due to Joule heat at the nip.
Also, by increasing or decreasing the number of heating elements according to the copy environment conditions, the optimum temperature can be similarly maintained in the nip portion, and a high-speed copy fixing roller can be provided.

Example 8 Configuration Examples of Electrodes and Brushes Instead of the configuration of the electrodes and brushes described with reference to FIGS. 1, 16 and 20, as shown in FIG.
The electrodes H1 ', H2', H3 ',.
The ring-shaped common electrode 230 is provided on the peripheral surface on the other end side. Further, an arc-shaped brush electrode 220 having terminals EL1 'to EL5' arranged at the same pitch as the electrodes H1 ', H2', H3 ',... Fixedly arranged, each terminal EL1 '
To EL5 'can be electrically connected to the respective electrodes on the fixing roller 20. In this case, when the width of the heating element EL is small and a sufficient electrode width cannot be obtained,
As shown in FIG. 22, each of the electrodes H1 ″, H2 ″, H
If 3 ″,... Are arranged in a zigzag pattern, each electrode can have a large area. In this case, the corresponding terminal EL1 ″
It is needless to say that .about.EL5 '' is also discharged in a staggered manner.

[0039]

According to the first aspect of the present invention, a thin film having a small heat capacity is used as a heating element.
With a low power consumption of about 00 to 300 W, and at most about 500 W, it is possible to obtain a sufficient fixing temperature and perform fixing.

According to the second aspect of the present invention, since the heating element is formed directly by using a heat insulating material such as ceramics or glass, the heat insulating element is formed on the surface of the solid material. In comparison, a fixing roller with a reduced number of steps can be provided.

According to the third aspect of the present invention, since the insulating layer has voids, the heat insulating property is improved, and the heating power can be concentrated only on the necessary portions, so that a fixing roller having high thermal efficiency can be obtained.

According to the fourth aspect of the present invention, the entire roller is heated, and since the heating element is a thin film, power consumption is small, and the heat capacity absorbed and lowered in the nip portion is rapidly compensated. A high-speed, high-efficiency power failure fixing roller can be provided.

According to the fifth aspect of the present invention, the heating element is made of a Ni / PTFE material, so that it is a thin-film heating element and does not have a peeling layer. Can be with rollers.

According to the sixth aspect of the present invention, a different current is applied to each of the plurality of heating elements to raise the temperature to the optimum temperature in the nip, and the number of the heating elements to be pre-heated is determined by the environmental conditions for fixing. By further increasing or decreasing, an optimal fixing temperature is obtained in the nip portion, and high-speed fixing is enabled.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a fixing roller.

FIG. 2 is a cross-sectional view of the roller in a state where an insulating heat-resistant material layer is formed on the surface of the roller-shaped base material.

FIG. 3 is a partially enlarged cross-sectional view illustrating a state in which a metal layer is formed on the surface of a roller base material.

FIG. 4 is a partially enlarged cross-sectional view illustrating a state in which a Ni-based heating element is formed on a metal layer.

FIG. 5 is a partially enlarged sectional view illustrating a state in which a Ni-based heating element is covered with a release agent layer.

FIG. 6 is a diagram illustrating a method of heating a nip portion of a fixing roller of a Ni-based heating element.

FIG. 7 is a diagram illustrating a configuration example of a Ni / PTFE-based heating element.

FIG. 8: Ni / PTFE between Ni / PTFE heating elements
FIG. 4 is a diagram illustrating a configuration of filling with fine particles.

FIG. 9 is a diagram illustrating a method of heating a nip portion of a fixing roller by a Ni / PTFE heating element.

FIG. 10 is a diagram schematically illustrating an electron micrograph of a toner supply Ni / PTFE fused layer.

FIG. 11 is a front view of a braided base material.

FIG. 12 is a diagram illustrating a state in which aluminum oxide is crystallized in a columnar shape.

FIG. 13 is an enlarged view illustrating a state where aluminum oxide is crystallized in a columnar shape.

FIG. 14 is a cross-sectional view when aluminum oxide crystallized in a column shape is sealed.

FIG. 15 is a cross-sectional view of a fixing roller having a gap in the vicinity of a peripheral surface.

FIG. 16 is a diagram illustrating a method of preheating each heating element.

FIG. 17 is a diagram illustrating an example of a temperature gradient when each heating element is preheated.

FIG. 18 is a diagram illustrating a method of preheating each heating element.

FIG. 19 is a diagram illustrating an example of a temperature gradient when each heating element is preheated.

FIG. 20 is a block diagram of a fixing roller temperature control device.

FIG. 21 is a perspective view illustrating an example of a fixing roller together with a configuration of an electrode and a brush.

FIG. 22 is a perspective view illustrating an example of a fixing roller together with configurations of an electrode and a brush.

[Explanation of symbols]

 5, 11, electrodeposition film (as a heating element) 8, 14, 20, fixing roller 19, (EL), heating element

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Koichi Kato 1-3-6 Nakamagome, Ota-ku, Tokyo, Ricoh Co., Ltd. (72) Inventor Takashi Kimura 1-3-6 Nakamagome, Ota-ku, Tokyo・ In Ricoh Co., Ltd.

Claims (6)

[Claims] 1. A fixing roller having a heating element capable of generating Joule heat formed on a surface portion of a substantially insulated roller-like base material, wherein said heating element is formed of a thin film having a thickness of 1 to 150 μm. A fixing roller formed by dividing one or a plurality of lines in a longitudinal direction of a base material. 2. A fixing roller according to claim 1, wherein said roller-shaped substrate is a hollow roller made of ceramics or glass. 3. The fixing roller according to claim 1, wherein aluminum or an aluminum alloy material is used as a material of the roller-shaped base material, and the roller-shaped base material is located near an outer peripheral surface of the roller-shaped base material. A fixing roller, characterized in that a void portion is formed in an inner portion of the fixing roller. 4. The fixing roller according to claim 1, wherein the one line includes a state covering the entire peripheral surface of the roller base material. 5. The fixing roller according to claim 1, wherein the heating element is formed on a conductive layer formed by electroless metal plating or vacuum deposition on the surface of the roller-shaped substrate. A fixing roller comprising a thin film formed by composite plating of nickel and a fluororesin. 6. A temperature control means for a fixing roller, wherein a heating element capable of generating Joule heat is formed on a surface portion of a substantially insulated roller-shaped base material, wherein the heating element is provided in a longitudinal direction of the roller-shaped base material. When the fixing operation is performed in combination with the backup roller formed by dividing the fixing roller into a plurality of lines in the direction, the heating of each of the heat generating elements is performed more in the fixing direction than in the nip portion with the backup roller in the rotation direction of the fixing roller. A method for controlling the temperature of a fixing roller, wherein preheating is performed so that the temperature is sequentially increased from an upstream side in a rotation direction of the roller, so that an optimum fixing temperature is obtained in a nip portion.