JP3466424B2 - Heat roller for fixing - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat roller for fixing toner in an electrophotographic apparatus such as a printer.

[0002]

2. Description of the Related Art Conventionally, in a toner fixing device in an electrophotographic apparatus such as a printer, a heat roller having a heat generating means and a pressure roller are arranged so as to face each other, and a sheet after printing is passed between these rollers. By doing so, the toner is heated and fixed.

As the heat roller, a metal pipe made of aluminum, stainless steel or the like provided with a heating element such as a halogen lamp has been used, but since the heat generation efficiency is poor, a warm-up time of 1 minute or more is required. In addition, there is a problem that the power consumption is large.

Therefore, a heat roller having a structure in which a heating resistor is provided on the outer peripheral surface of a cylindrical body made of a metal pipe through an insulating layer made of an organic resin such as polyimide, and a release layer is further provided on the surface is proposed. (JP-A-55-7239)
No. 0, JP-A-62-200380).

Further, there has been proposed a fixing heat roller having a structure in which a heating resistor is provided on the inner peripheral surface side of a cylindrical body via an insulating layer and a release layer is provided on the outer peripheral surface side of the cylindrical body (special feature). Kaisho 5
5-72390, etc.).

[0006]

However, in the case of a fixing heat roller having a heating resistor on the surface of such a cylindrical body through an insulating layer, the cylindrical heating roller may be damaged due to poor insulation of the insulating layer during long-term use. There is a problem that an accident such as a short circuit between the body and the heating resistor is likely to occur.

[0007]

In view of the above, the present invention provides:
A fixing heat roller comprising a heating resistor provided on an inner peripheral surface of a metal cylindrical body through an insulating layer, and a release layer on an outermost peripheral surface, the surface of the inner peripheral surface of the metal cylindrical body. The roughness has a maximum height (Rmax) in the range of 0.8 to 50 μm, and there is no protrusion exceeding 50 μm in height on the inner peripheral surface of the metal cylindrical body, and there is a protrusion of 20 to 50 μm in height. It is characterized in that the number is less than ² per cm ² , and the number of protrusions having a height of 10 to 20 μm is less than 5 per cm ² . The metal pipe forming the metal cylinder is aluminum, aluminum alloy, iron, iron alloy, or stainless steel having a thermal conductivity of 0.03 cal / ° C · cm · sec or more and a thickness of 0.5 to 1 mm, and ,
The heating resistor formed on the insulating layer has a thickness of 5 to 10
0 μm Ag, Ni, Au, Pd, Mo, Mn, W, R
At least one conductive agent selected from e ² O ³ , Mn ² O ³ , and LaMnO ³ and a synthetic resin or glass forming a matrix are used.
Is a mixture containing ˜90% by weight, and an electrode member is connected to the heating resistor, and the electrode member is brass, copper, copper alloy, stainless steel, or a metal surface of which is plated with nickel. , The difference in coefficient of thermal expansion from the metal cylinder is within 10 × 10 ⁻⁶ / ° C., and the electrical resistivity is 10
It is characterized in that it is μΩ · cm or less and the melting point is 800 ° C. or more.

According to the present invention, the surface of the cylindrical body does not have protrusions having a height of more than 50 μm, and the height is 20 to 50 μm.
The number of protrusions of m is less than ² per cm ² , and the number of protrusions of 10 to 20 μm in height is less than 5 per cm ² .

That is, the cylindrical body is often formed by drawing a metal pipe, and there are many projections on the surface thereof, and the surface roughness is 70 to 13 at the maximum height (Rmax).
It is about 0 μm. Therefore, the thickness of the insulating layer becomes thin at the protruding portion, so that defective insulation is likely to occur. Therefore, in the present invention, it was found that the insulation failure can be prevented by removing the protrusions existing on the surface of the cylindrical body so that the maximum height (Rmax) is within the range of 0.8 to 50 μm.

Moreover, even within the above range, if the number of protrusions is large, insulation failure is likely to occur.
On the surface of the cylindrical body, there are no protrusions with a height of more than 50 μm, the number of protrusions with a height of 20 to 50 μm is less than ² per cm ² , and the number of protrusions with a height of 10 to 20 μm is 5 per cm ^2. The inventors have found that if the number is less than the number, the insulation failure can be further prevented.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the fixing heat roller of the present invention is provided with an insulating layer 2 on an inner peripheral surface 1a of a cylindrical body 1 made of a metal pipe, and a heating resistor 3 is formed on the insulating layer 2. Then, the electrode member 5 is joined to the end portion of the heating resistor 3 by using the conductive adhesive 4, and the release layer 6 is provided on the outer peripheral surface of the cylindrical body 1. Although only one end is shown in FIG. 1B, the conductive terminal members 5 are similarly fixed to both ends.

The electrode member 5 has a lid-like shape that closes the hollow hole of the cylindrical body 1, has a protruding portion formed at the center, and has its end face serving as a sliding face 5a with the power feeding member 7. And
When this heat roller for fixing is used, the power supply member 7 is brought into contact with the sliding surface 5a of the electrode member 5 provided at the end while rotating the cylindrical body 1, and power is supplied while sliding. The heating resistor 3 can be energized to generate heat.

Further, the metal pipe forming the cylindrical body 1 is
It is made of a metal having a thermal conductivity of 0.03 cal / ° C · cm · sec or more, and specifically, aluminum, an aluminum alloy, iron, an iron alloy, stainless steel, or the like is used, and its thickness is 0.5 to 1 mm.

Then, as shown in FIGS. 2 (a) and 2 (b),
The inner peripheral surface 1a of the cylindrical body 1 has a single or streak-like protrusion 1b generated in the manufacturing process thereof. However, in the present invention, the surface roughness of the inner peripheral surface 1a including the protrusion 1b has the maximum height. (Rmax) is in the range of 0.8 to 50 μm.

Here, the reason why the above range is limited is that if the maximum height (Rmax) is less than 0.8 μm, the adhesion strength of the insulating layer 2 may be reduced, and there is a possibility that a partial profit may occur during use. On the other hand, when it exceeds 50 μm, it becomes impossible to maintain a predetermined electric insulation.

Further, the inner peripheral surface 1a has a height of 50 μm.
There are no protrusions exceeding m, the number of protrusions with a height of 20 to 50 μm is less than ² per cm ² , and the height is 10 to 2
The number of 0 μm protrusions is less than 5 per 1 cm ² .

That is, even within the above range of surface roughness,
Since the insulation failure is likely to occur when the number of the protrusions 1b is large, as a result of various experiments, it was found that the number of the protrusions 1b should be within a predetermined range.

For example, as shown in the cross-sectional view of the cylindrical body 1 in FIG. 3, the insulating layer 2 is thinned at the portion where the protrusion 1b is present and the insulating property is deteriorated. However, in the present invention, the maximum height (Rma
x) is 50 μm or less and there is no protrusion 1b having a height h of more than 50 μm, so that the insulating layer 2 does not become extremely thin. Moreover, the protrusion 1 having a height h of 50 μm or less
Also for b, the thinned portion of the insulating layer 2 can be reduced by reducing the number thereof. As a result, the electric insulating property of the insulating layer 2 can be favorably maintained.

In the present invention, in order to measure the surface roughness of the inner peripheral surface 1a of the cylindrical body 1 and the number of the projections 1b, for example, the cylindrical body 1 of the heat roller for fixing as shown in FIG. The insulating layer 2 is peeled off by cutting along the axial direction and immersing in water for several hours to expose the exposed inner peripheral surface 1.
It suffices to measure a.

The specific surface roughness is measured according to JIS B
The surface roughness of the inner peripheral surface 1a may be measured using, for example, a stylus type surface roughness meter. In addition, the number of the protrusions 1b is determined by measuring a plurality of points on the inner peripheral surface 1a using the same surface roughness meter and averaging the protrusions 1b having a height of 10 to 20 μm per cm ² , The number of protrusions 1b having a size of 20 to 50 μm may be calculated respectively.

Alternatively, when it is difficult to directly measure the inner peripheral surface 1a, a methyl cellulose sheet swollen with methyl acetate is attached to the inner peripheral surface 1a, the surface is transferred and then peeled off, and then dried. The surface roughness and the like described above can be measured on the sheet.

Alternatively, as a simple measuring method, the number of the protrusions 1b can be counted by observing the inner peripheral surface 1a of the cylindrical body 1 with an endoscope or the like.

[0024] Incidentally, if the projection 1b is a single protrusion as shown in FIG. 2 (a), counts the number of the projections 1a, 1 cm ²
Calculate the number of hits. Further, in the case of the streak-like projection 1b as shown in FIG. 2B, one streak is counted as one, and the stylus is moved in the direction perpendicular to the direction of the streak for measurement.
Calculate the number of protrusions 1b per 1 cm of measurement length and
The number of protrusions 1b per cm ² is set.

Further, in order to adjust the surface roughness and the number of projections 1b on the inner peripheral surface 1a of the cylindrical body 1, chemical treatment or the like may be performed in the manufacturing process of the cylindrical body 1. For example, cylindrical body 1
Is formed by the above-mentioned metal pipe drawing process,
The inner peripheral surface 1a is ground as necessary, but thereafter, the inner peripheral surface 1a is treated with a chemical such as caustic soda to reduce the protrusions 1b and the surface roughness. Then, the surface roughness and the number of the protrusions 1b may be adjusted within the above range by adjusting the time of the chemical treatment.

The insulating layer 2 is made of polyimide, phenol, polyimide amide, polyamide imide, silicon,
It is made of a resin having excellent heat resistance such as borosiloxane, and its thickness varies depending on the dielectric strength, but for example, in the case of polyimide, a thickness of 10 to 200 μm is preferable. This is to maintain good electrical insulation, and preferably 20 to
The range is 150 μm, more preferably 50 to 70 μm.

Further, as the heating resistor 3, a mixture of a conductive agent and a synthetic resin or glass forming a matrix is used. As the conductive agent, Ag, Ni, Au, Pd, Mo,
Metal materials such as Mn and W, or Re ₂ O ₃ and Mn
_At least one metal compound such as ₂ O ₃ and LaMnO ₃ is used. Further, the glass forming the matrix may be either crystallized glass or non-crystallized glass, but by using crystallized glass, the change in resistance value can be reduced even by a heating / cooling cycle.

The synthetic resin or glass forming the above matrix is necessary for improving the strength of film formation.
˜90% by weight. Also, the heating resistor 3
The thickness is preferably 5 to 100 μm.

Alternatively, the heating resistor 3 may be formed of a single metal and may be formed by plating or the like.

Further, the electrode member 5 has a difference in coefficient of thermal expansion from the cylindrical body 1 within 10 × 10 ⁻⁶ / ° C. and an electric resistivity of 10.
Use those with a melting point of 800 ° C
Specifically, brass, copper, copper alloy, stainless steel, or the like, or a metal surface of which is plated with nickel or the like is used.

Next, a method of manufacturing the fixing heat roller of the present invention will be described.

First, the cylindrical body 1 made of a metal pipe is processed into a predetermined shape, the surface roughness of the inner peripheral surface 1a and the number of projections 1b are adjusted by the above-described method, and then the insulating layer 2 is spun on the inner peripheral surface 1a. It is applied by coating, spray coating, dipping or the like, and baked in air at 200 to 450 ° C. or in a nitrogen atmosphere. On this, a heating resistor component was mixed with an organic solvent, a binder, a dispersant, etc. to form a paste, which was applied by screen printing, dipping, spray coating, etc. and baked at 400 to 500 ° C. And

Thereafter, if necessary, the heating resistor 3 is subjected to laser trimming to adjust the resistance value, and then the cylindrical body 1
The outer peripheral surface of is coated with a release layer 6. Finally, if the electrode member 5 is bonded to a predetermined place with the conductive adhesive 4, the fixing heat roller of the present invention can be obtained.

In the embodiment of FIGS. 1 and 2, the cylindrical body 1
By providing the heating resistor 3 on the inner peripheral surface 1a side of
It is possible to provide a fixing heat roller that is highly resistant to fire and has high safety. However, the present invention is not limited to this embodiment, and a heating resistor may be provided on the outer peripheral surface of the cylindrical body 1 via an insulating layer, and a release layer may be provided on this surface. In this case, the surface roughness of the outer peripheral surface of the cylindrical body and the number of protrusions may be set within the above range.

[0035]

EXAMPLES Example 1 Examples of the present invention will be described below.

A fixing heat roller shown in FIG. 1 was prototyped. The cylindrical body 1 is made of aluminum and has an outer diameter of 20 mm,
A length of 280 mm, a wall thickness of 1.0 mm, a treatment time with caustic soda, and different surface roughness of the inner peripheral surface 1a were prepared, and the maximum height (Rmax) of the inner peripheral surface 1a was obtained by the above-mentioned methods. Was measured. A heating resistor 3 made of a mixture of a conductive agent and glass was formed on the inner peripheral surface 1a via an insulating layer 2 made of polyimide and having a thickness of 30 to 60 μm, and the resistance value was adjusted by laser trimming. I made something that didn't exist.

An aluminum foil is laid on each heating resistor 3, and when a voltage of 1.5 kV is applied between the aluminum foil and the cylinder 1, it is examined whether insulation breakdown occurs in the insulating layer 2 and insulation is performed. The sex was evaluated.

The results are shown in Table 1. From this result, the surface roughness of the inner peripheral surface 1a of the cylindrical body 1 is determined to be the maximum height (Rma
It was found that dielectric breakdown does not occur if x) is set in the range of 0.8 to 50 μm.

[0039]

[Table 1]

Example 2 Next, the matrix component of the heating resistor 3 is lead glass, and the inner peripheral surface 1a of the cylindrical body 1 has a surface roughness of 0.8 to 50 μm.
A fixing heat roller was manufactured in the same manner as in Example 1 except that the heat roller was adjusted to be within the range of m. 10 to 10 at arbitrary positions on the inner peripheral surface 1a of the cylindrical body 1, respectively.
The number of single protrusions of 20 μm and 20 to 50 μm was examined, and the average value thereof was calculated.

After that, the insulation property was evaluated in the same manner as in Example 1.

The results are shown in Table 2. From this result, the protrusion 1b having a height of 10 to 20 μm is formed on the inner peripheral surface 1a by 1c.
There are 5 or more per m ² , or a height of 20 to 50 μ
In the case where two or more m projections were present per cm ² , the insulating property could not be maintained. On the other hand, the number of protrusions 1b having a height of 10 to 20 μm present on the inner peripheral surface 1a is less than 5 per 1 cm ² , and the number of protrusions 1b having a height of 20 to 50 μm is less than ² per 1 cm ² , It can be seen that good insulation can be maintained.

[0043]

[Table 2]

Example 3 Next, a fixing heat roller was produced in the same manner as in Example 2 except that the cylindrical body 1 having the streaky protrusions 1b on the inner peripheral surface 1a was used.

Each of the inner peripheral surfaces 1a is the same as in the second embodiment.
The number of the protrusions 1b existing in 1 was examined, and the insulating property was evaluated.

The results are shown in Table 3. From this result, the protrusions 1 existing on the inner peripheral surface 1a and having a height of 10 to 20 μm
b is less than 5 per 1 cm ² and the height is 20 to 5
The number of 0 μm protrusions per cm ² is less than 2
It can be seen that good insulation can be maintained.

[0047]

[Table 3]

[0048]

As described above, according to the present invention, the fixing heat roller is provided with the heating resistor provided on the inner peripheral surface of the cylindrical body through the insulating layer and the release layer on the outer peripheral surface. Then, the surface roughness of the inner peripheral surface of the cylinder is set to the maximum height (Rmax) 0.8.
By setting the thickness in the range of ˜50 μm, the electric insulation of the insulating layer can be favorably maintained for a long period of time.

Further, according to the present invention, there is no protrusion exceeding 50 μm in height on the inner peripheral surface of the cylindrical body, and the height is 20
The number of protrusions of ~ 50 μm is less than ² per 1 cm ² ,
In addition, the number of the protrusions having a height of 10 to 20 μm is set to less than 5 per 1 cm ^2, so that the electric insulation of the insulating layer can be further favorably maintained.

As a result, a fixing heat roller having high performance and excellent durability can be easily obtained.

[Brief description of drawings]

1A is a side view showing a fixing heat roller of the present invention, and FIG. 1B is a sectional view taken along line XX in FIG.

2A and 2B are partially cutaway perspective views of a cylindrical body used in the fixing heat roller of the present invention.

FIG. 3 is an enlarged cross-sectional view of the inner peripheral surface side of the cylindrical body in the fixing heat roller of the present invention.

[Explanation of symbols]

1: Cylindrical body 1a: inner peripheral surface 1b: protrusion 2: Insulation layer 3: Heating resistor 3a: inner peripheral surface 4: Conductive adhesive 5: Electrode member 6: Release layer 7: Power supply member

Claims (2)

(57) [Claims] 1. A fixing heat roller comprising a heating resistor provided on an inner peripheral surface of a metal cylindrical body with an insulating layer interposed therebetween, and a release layer on an outermost peripheral surface of the metal cylindrical body. The surface roughness on the inner peripheral surface is the maximum height (Rmax) 0.8 to 50.
In the range of μm, the inner peripheral surface of the metal cylindrical body,
20-50 μm height with no protrusions over 50 μm height
Less than ² protrusions per cm ² and a height of 10
A fixing heat roller characterized in that the number of protrusions having a size of 20 μm is less than 5 per 1 cm ² . 2. The metal pipe forming the metal cylinder is heat transfer
If the conductivity is 0.03cal / ° C · cm · sec or more, the thickness is
0.5-1 mm aluminum, aluminum alloy,
Iron, iron alloy, or stainless steel, and
The heating resistor formed on the edge layer has a thickness of 5 to 100 μm.
Ag, Ni, Au, Pd, Mo, Mn, W, Re
² O ³ , Mn ² O ³ , LaMnO ³ At least one type of conductivity
Agent and 10 or more synthetic resin or glass forming the matrix
It is a mixture containing 90% by weight, and the heat generating resistor is
Connect the electrode member, which is made of brass, copper, copper
Gold, stainless steel, or nickel on the surface of these metals
It is plated and has thermal expansion with the above metal cylinder.
10% difference in tension ^-6 / ° C or less, electrical resistivity is 10
Characterized by μΩ · cm or less and melting point of 800 ° C or more
The fixing heat roller according to claim 1.