JP2002278343A - Pressure relief valve and oil application device equipped with the same - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To maintain the hermeticity, open in response to the rise of the extremely small pressure of the gas phase in the hermetic compartment, return the hermetic compartment to atmospheric pressure, and take up the attached area. To provide a pressure relief valve having a simple structure and an oil application device to which the valve is mounted. SOLUTION: A partition wall section 5 for partitioning the outside air and the pressure adjustment chamber.
And a rubber sheet 1 having a hardness of 10 to 80
The rubber-like sheet is formed with cuts 3 penetrating the front and back surfaces, and the pressure regulating chamber is opened at a pressure of 1 to 100 KPa.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure relief valve having a simple structure, which opens in response to an extremely small pressure increase in a gas phase in a closed compartment, and an oil applying device to which the valve is mounted.

[0002]

2. Description of the Related Art Conventionally, pressure inside an enclosed space for general equipment such as office equipment and precision equipment has risen to an extremely small level due to the inflow and outflow of air and the thermal expansion of air due to an increase in the operating temperature. In some cases, adverse effects such as hindering smooth operation of the device and affecting related devices may be problematic. As a pressure buffer mechanism that suppresses a rise in pressure in the closed compartment in response to a rise in the minute pressure of the gas phase in these closed compartments,
The use of a diaphragm, a flexible PTFE tube, or the like in a partition wall between the outside air and the inside of the closed compartment is disclosed.

In a fixing device such as an electrostatic copying machine or an electrophotographic printer, when fixing the toner transferred onto a recording paper as a subject, the toner may adhere to a heat fixing roll. In order to prevent the recording paper from being stained, apply a small amount of release oil such as silicone oil to the heat-fixing roll with an oil application roller, so that toner adheres to the heat-fixing roll or the recording paper adheres I try not to go up. As shown in FIG. 9, for example, an oil application roller having such a function uses a cylindrical molded body made of a metal perforated hollow pipe e and stores release oil g in an oil holding tank f. The above-mentioned oil transfer layer c and oil application amount control layer d are wound around and adhered to the surface thereof, and further, a tubular member or a diaphragm for releasing the thermal expansion of the air layer interposed in the oil holding tank to the outside air. (See JP-A-10-10906).

[0004]

However, a conventional pressure buffer mechanism such as a tubular member or a diaphragm is
Although it is an effective means for absorbing a pressure of 1 to 30 KPa or releasing it to the outside, there is a problem that the installation area is large and the use place is limited. In addition, it is difficult to select a tubular member or a membrane member, and it does not always operate with high accuracy. Further, there are problems such as an increase in cost.

Accordingly, an object of the present invention is to maintain the hermeticity, open in response to the rise of the extremely small pressure in the gas phase portion in the closed compartment, return the inside of the closed compartment to atmospheric pressure, and provide an attached area. It is an object of the present invention to provide a pressure relief valve having a simple structure that does not take any measures, and an oil application device to which the valve is mounted.

[0006]

Under such circumstances, the present inventors have conducted intensive studies, and as a result, a rubber sheet having a hardness of 10 to 80, which is attached to a partition wall for partitioning the atmosphere and the pressure adjustment chamber. In the form, a cut formed through the front and back surfaces was formed, and the gauge pressure of the pressure adjustment chamber was 1 to 100 KPa.
Pressure, and the pressure adjustment chamber can be held at a predetermined pressure lower than the opening pressure. In addition, a rubber-like sheet having a hardness of 5 to 50 after swelling of silicone oil penetrates the front and back surfaces. When the gauge pressure in the pressure regulating chamber opens with a pressure difference of 1 to 30 KPa,
It is also possible to prevent the leakage of the silicone oil filled in the pressure adjustment chamber to the outside, and found that it is extremely effective for an oil application device having a hollow cylindrical silicon oil holding member and the like, and found the present invention. It was completed.

That is, the present invention (1) is provided on a partition wall for partitioning the outside air and the pressure adjusting chamber, and has a hardness of 10 to 80.
The rubber-like sheet-like material is formed with cuts penetrating the front and back surfaces, and the gauge pressure of the pressure adjusting chamber is opened at a pressure of 1 to 100 KPa. To provide a pressure relief valve. By adopting such a configuration, for example, if the pressure relief valve is attached to the top plate of the silicon oil storage tank of the pad type oil application device described later, the silicon oil or air thermally expands by heating from the fixing roller, Even if the pressure in the gas phase of the silicon oil storage tank rises, the pressure is released to the outside air by the action of the pressure release valve, which causes adverse effects such as excessive application of silicon oil and oil leakage due to the pressure increase in the gas phase. Can be prevented.

Further, the present invention (2) provides a rubber member having a hardness of 5 to 50 which is attached to a hollow portion of a hollow cylindrical silicone oil holding member formed of a porous molded body and a flange for partitioning outside air. The rubber sheet is formed with cuts penetrating the front and back surfaces, and the gauge pressure of the pressure adjusting chamber is opened at a pressure of 1 to 30 KPa. This is to provide a withdrawal valve. By adopting such a configuration, for example, if the pressure relief valve is attached to flange portions attached to both ends of the hollow cylindrical silicon oil holding member of the oil application roller,
Even if silicon oil or air thermally expands due to the heat from the fixing roller and the pressure in the gas phase in the hollow rises, the pressure is released to the outside air by the action of the pressure release valve, and the pressure in the gas phase rises This can prevent adverse effects such as excessive application of silicone oil and oil leakage. In addition, the pressure relief valve has a minute cut through the front and back surfaces, and has a closing effect of the cut portion due to swelling of the silicon oil, so that the pressure release valve is immersed in the silicon oil filled in the hollow portion. Also, no silicone oil leaks from the pressure release valve.

The present invention (3) is characterized in that the hollow cylindrical silicon oil holding member made of the porous molded body is a silicon oil holding member of an oil application roller. This is to provide a withdrawal valve. By adopting such a configuration, the same effects as those of the invention described in the above (2) can be obtained.

In the present invention (4), the rubber-like sheet-like material is a disc-like silicone rubber attached to a part of the flange, and has a thickness of 0.3 to 2.0 mm and a diameter of 0.3 to 2.0 mm. 3.0
The pressure relief valve according to the above (2) or (3), wherein the pressure relief valve has a diameter of from 6.0 mm to 6.0 mm. With such a configuration, it is possible to easily determine a suitable pressure relief valve suitable for the properties of the silicone oil holding member of the oil application roller, the properties of the rubbers, and the like.

In the present invention (5), an oil coating layer is provided on a lower outer periphery of a silicon oil holding member made of a porous molded body attached to the bottom of a silicon oil storage tank, and the oil holding layer is held by the oil holding member. In an oil applicator that supplies release oil to the fixing roll, release oil is injected into the silicon oil storage tank, and the (1) is placed on the top plate between the gas phase portion of the silicon oil storage tank and the outside air. The present invention provides an oil application device provided with the pressure relief valve described in (1). By adopting such a configuration, the same effect as described in the above (1) can be obtained particularly in a pad-type oil application device having a silicon oil storage tank.

Further, the present invention (6) provides an oil coating layer on the outer periphery of a hollow cylindrical silicone oil holding member made of the porous molded body, and releases the release oil held by the oil holding member to a fixing roll. In the supplied oil applying roller, the hollow portion is filled with release oil, and the pressure relief valve of (2) to (4) is attached to a flange portion that separates the hollow portion from the outside air. The present invention provides an oil application roller characterized by the following. By adopting such a configuration, particularly in the oil application roller, the above (2) to (2)
The same effect as described in (4) is obtained.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to embodiments and with reference to FIGS. FIG. 1 is a perspective view of the pressure relief valve according to the first embodiment, and FIG. 2 is a diagram illustrating an operation state of the pressure relief valve of FIG. In addition,
In FIGS. 1 and 2, the turning of the piece 4 formed by the cut 3 of the pressure relief valve 1 is exaggerated to explain the structure of the pressure relief valve 1, and is actually in a closed state. Even if it is operated by a rise in pressure, the piece 4 is also hard and does not open in this way. The pressure relief valve 1 according to the present invention is a rubber sheet having a hardness of 10 to 80, which is attached to a partition wall portion 5 that partitions the outside air and the pressure regulation chamber. What was formed,
The gage pressure of the pressure adjusting chamber is opened at a pressure of 1 to 100 KPa.

Examples of the rubber material for the pressure relief valve include silicone rubber, fluorine rubber, and the like. Among them, silicone rubber can select an appropriate hardness range, and the cutting process is easy. When used in an oil application device, it is preferable in that it has oil swelling properties. Rubbers having a hardness of 10 to 80, preferably 20 to 60 can be used. If the hardness of the rubbers is less than 10, the sealing force is poor, and if there is a silicone oil other than air, for example, in the pressure adjusting chamber, oil leakage occurs when the pressure release valve is immersed in the silicone oil, which is not preferable. On the other hand, if the hardness of the rubbers exceeds 80, it will not open even if the gauge pressure in the pressure adjustment chamber exceeds 100 KPa. Without causing oil leakage. As described above, when the hardness of the rubbers is in the above range, it is possible to suppress the rise of the minute pressure generated in the use environment while maintaining the tightness of the pressure adjustment chamber. The hardness of the rubber can be measured by a method based on JIS K6253 (hardness test method).

The shape of the notch 3 is a cross-shaped notch passing through the center of a circle in the present embodiment, but is not limited thereto, and examples thereof include an I-shape and a Y-shape. The notch 3 can be easily formed by using a sharp cutter. As a method for attaching a pressure release valve to a partition wall such as a metal flange, there is provided a method in which an opening (hole) having substantially the same size as the pressure release valve is provided in the partition wall, and the pressure release valve is fitted to the opening. For example, a method of bonding with an adhesive is used. Further, as the shape of the sheet-like material of the pressure release valve, various shapes such as a square shape, an elliptical shape, etc. can be used in addition to the circular shape in the present example. The number of pressure release valves is not particularly limited, and is 1 or more, preferably 2 to 4.

The pressure relief valve 1 of this embodiment is provided on a partition wall for partitioning the outside air and the pressure control chamber, and the gauge pressure of the pressure control chamber is opened at a pressure of 1 to 100 KPa. In order to make the valve open in the range, the hardness, the thickness, the number of the rubbers, the number of holes, the hole diameter, the shape of the cut, and the like are determined as appropriate. Usually, the harder the rubber,
The thicker the thickness, the smaller the number of installations, and the smaller the hole diameter, the higher the pressure relief valve that operates at a higher pressure. When the gauge pressure of the pressure adjustment chamber falls within the above range, the pressure relief valve pushes the piece 4 formed by the cut of the pressure relief valve 1 attached to the partition wall to the outside air side. Due to the generation of the minute gap, the expanded air or the like escapes to the outside air side. When the pressure in the pressure adjustment chamber returns to the predetermined pressure, the gap is closed by the restoring force of the piece 4 of the pressure release valve.

The pressure adjustment chamber is a sealed compartment which forms a part of all equipment such as office equipment and precision equipment, and is provided by the inflow and outflow of air generated with the passage of time and the rise in temperature of itself or peripheral equipment. The pressure is extremely increased due to the thermal expansion of the air. For example, the air in the hollow portion of the oil application roller using the hollow cylindrical silicon oil holding member, the air in the silicone oil storage tank of the pad-type oil application device. Phase part and the like. The pressure adjusting chamber may be a chamber in which a fluid such as silicone oil is present as long as it has a gas phase portion. The term "sealing" means a completely closed state, as well as a semi-sealed state in which outside air flows in and out with time as in a closed section surrounded by a porous molded body.

The pressure relief valve according to the second embodiment of the present invention is provided on a hollow portion of a hollow cylindrical silicone oil holding member formed of a porous molded body and a flange for partitioning the outside air, and has a hardness after swelling of the silicone oil. Is a sheet of rubber having a thickness of 5 to 50, and the sheet of rubber is formed with cuts penetrating the front and back surfaces, and the pressure in the pressure adjusting chamber is opened at a pressure of 1 to 30 KPa. Things. The hollow cylindrical silicon oil holding member made of the porous molded body is used, for example, as a silicon oil holding member of an oil application roller.

In the pressure relief valve according to the second embodiment,
The description of the same configuration as that of the pressure relief valve of the first embodiment will be omitted, and only different points will be described. That is, in the pressure relief valve of the present embodiment, the difference from the pressure relief valve of the first embodiment is that the partition wall to be attached is separated from the hollow portion of the hollow cylindrical silicone oil holding member made of a porous molded body by the outside air. Is that the hardness is 5 to 50 in hardness after swelling of the silicone oil.

The hollow cylindrical silicone oil holding member may have any structure capable of holding silicone oil, and is particularly preferably a porous molded body mainly composed of heat-resistant inorganic fibers. The hollow cylindrical porous molded body mainly composed of this heat-resistant inorganic fiber, for example, the one containing a small diameter voids and pores in a desired ratio inside, the oil holding capacity by the pore group is increased, Since the oil movement is appropriately adjusted by the fine gap between the fibers, the oil can be applied evenly while controlling the amount of the release oil, the use efficiency of the release oil is high, and oil leakage can be suppressed. Such a hollow cylindrical silicone oil holding member has an average fiber diameter of 1 to 300 μm.
m, heat-resistant fiber 100 having an average fiber length of 0.03 to 100 mm
1 parts by weight, water-resistant inorganic filler 1 having an average particle size of 0.01 to 2 mm
0 to 200 parts by weight, inorganic binder 5 to 300 parts by weight, organic binder 1 to 100 parts by weight, water-resistant granular organic substance 1 to 300
It is manufactured by molding a kneaded product composed of 50 parts by weight of water and 50 to 300 parts by weight of water into a hollow cylindrical shape, drying, degreasing and firing. The flange to which the pressure relief valve of this example is attached is a circular shape which is air-tightly mounted on both ends of the hollow cylindrical silicone oil holding member, for example, a metal one is used. The installation position of the pressure relief valve on the flange is not particularly limited, but, for example, when a plurality of circular flanges are provided, it is preferable that the circular area is a region in which a circular area is equally divided into radial cuts, and the vicinity of an outer peripheral portion in a radial direction. .

The hardness of rubbers after swelling of silicone oil is 5
To 50, preferably 20 to 40 can be used. Swelling with silicone oil is carried out by adding a rubber to a silicone oil having a kinematic viscosity of 50 to 300 cSt at 25 ° C at room temperature.
It is obtained by heating to 70 ° C. and immersing at this temperature for 10 to 100 hours. The hollow cylindrical silicone oil holding member in which the pressure relief valve of this example is used is usually filled with silicone oil. In particular, when this is used for an oil application roller, the hollow cylindrical silicone oil holding member rotates around its axis. For this reason, silicone oil is immersed in the pressure relief valve, but even if there is a cut in the pressure relief valve, stress acts on the side that increases the sealing performance due to swelling.
Suppress external leakage of silicone oil. If the hardness of the rubbers after swelling of the silicone oil is less than 5, the sealing force is poor. For example, when silicone oil is present, oil leakage occurs, which is not preferable. On the other hand, if the hardness of the rubbers after the swelling of the silicone oil exceeds 50, the pressure relief valve will not open even if the gauge pressure of the pressure adjustment chamber exceeds 100 KPa. When used as, the expanded air does not escape, and oil leaks from the peripheral surface of the hollow cylindrical silicone oil holding member.

Further, the ventilation resistance of the pressure relief valve of this embodiment is 0.5.
1 to 2.5 MPa · s / m ³ , preferably 0.3 to 1.0 MP
a · s / m ³ If the airflow resistance is less than 0.1 MPa · s / m ³ , the hollow cylindrical silicone oil holding member cannot be hermetically sealed, and oil leaks from the pressure relief valve.
On the other hand, if the pressure exceeds 2.5 MPa · s / m ³ , the inflated air leaks from the peripheral surface of the hollow cylindrical silicon oil holding member without coming out of the pressure release valve, which is not preferable in that various adverse effects are caused. The airflow resistance was measured according to ASTM / C-522-87. Specifically, a ventilation resistance measuring device 30 shown in FIG. 3 was used. The device 30 includes a cylindrical pressure vessel 34 having an open end, a differential pressure gauge 31, a flow meter 32, and a compressor 33, and fixes a sample 35 air-tightly fixed in the cylindrical pressure vessel 34, A predetermined flow rate of air is sent to the sample 35, the differential pressure is determined by the differential pressure gauge 31, and the following equation;
s / m ³ ) = P / U (where P is differential pressure Pa, U is flow rate (m ³ / s))
The airflow resistance was determined from. In FIG. 3, l ₁ is 20 mm and l ₂ is 30 mm. The ventilation resistance was calculated as a value at a flow rate of 2.7 cm ³ / min.

FIG. 4 is a side view showing an installation state of an oil application roller using a hollow cylindrical silicon oil holding member in a fixing device. FIG. 5 is an axial sectional view of the oil application roller provided with a pressure release valve. 6 is a perspective view of a flange portion provided with the pressure release valve of this example. In the figure, reference numeral 8 denotes an oil application roller. The oil application roller 8 is provided with an oil application layer 16 on the outer periphery of a hollow cylindrical silicon oil holding member 15 and is released from the hollow cylindrical silicon oil holding member 15. Silicon oil, which is an oil, is supplied to the heating and fixing roll 11 which is an application surface. The hollow cylindrical silicon oil holding member 15 is provided with a hollow portion 152, and the hollow portion 152 is filled with a release oil 153. The pressure release valve 1 for releasing a minute pressure in the hollow portion 152 is provided on a flange 18 that separates the hollow portion 152 from the outside air. The oil application roller 8 is incorporated in a fixing device 10. The fixing device 10 passes the recording paper 9 between the heat fixing roll 11 and the pressure roll 12 and transfers the recording paper 9 to the front surface 9 a of the recording paper 9. The oil applying roller 8 is fixed to the heat fixing roll 11 so that the toner 13 on the surface 9a of the recording paper 9 does not adhere to the heat fixing roll 11.
And fix the silicone oil 153 with the heat fixing roll 1
1 is applied to the peripheral surface.

Hollow cylindrical silicon oil holding member 15
Has a total porosity of 40 to 80% and silicone oil 15
2 can be held in a group of pores, flanges 18 are provided at both ends in a liquid-tight manner, and a shaft 19 is mounted on the axis of the flange 18 in a liquid-tight manner.
2 are formed. Therefore, the hollow portion 152 is formed in a cylindrical tank shape by being surrounded by the hollow cylindrical silicone oil holding member 151, the flanges 18 provided at both ends thereof, and the shaft 19 attached to both the flanges 18. The thickness of the hollow cylindrical silicone oil holding member 151 is not particularly limited, but is appropriately determined, for example, in the range of 1 to 10 mm. Hollow cylindrical silicon oil holding member 1
If the thickness of 51 is too large, the volume of the hollow portion 152 becomes small, and the utilization rate of the release oil decreases. On the other hand, if the thickness of the hollow cylindrical silicon oil holding member 151 is too small, the oil holding capacity is reduced, and oil leakage easily occurs as in the case of the conventional metal perforated pipe.

As the flanges 18 attached to both ends of the hollow cylindrical silicone oil holding member 15, for example, those shown in FIG. 6 can be used. In FIG. 6, a flange 18 forms a circular hole at the center of four radii formed by dividing a circular sheet-like material 18a into a cross, and the four circular holes have a disk shape as shown in FIG. The pressure relief valve 1 made of silicone rubber is fitted therein. Each pressure relief valve 1 has a cross cut. The pressure relief valve 1 may be, for example, one having a thickness of 0.3 to 2.0 mm and a diameter of 3.0 to 6.0 mm. Further, since a similar flange 18 is mounted on the other end surface of the silicone oil holding member 15, the oil application roller 8 has eight pressure relief valves 1.
Will be attached.

In the oil application roller 8 according to the present invention, the oil application layer 16 provided on the outer periphery of the hollow cylindrical silicon oil holding member 15 made of a porous molded body is composed of the oil transfer layer 16a and the oil provided thereon. And a coating amount control layer 16b. The oil transfer layer 16a is made of heat-resistant fiber felt, is wound around the outer periphery of the oil holding member 15, absorbs the release oil from the oil holding member 15, and supplies the release oil to the oil application control layer 16b. I am carrying it. The heat-resistant fiber felt used here has a thickness of 1 to 3 mm and a density of 100 to 800 kg / m ³ , but is not particularly limited. The release oil is usually 50
A low viscosity silicone oil of ~ 300 cSt (25 ° C) is used.

The oil application amount control layer 16b is not particularly limited as long as it has an air permeability of 10 to 2000 seconds / 100 cc and allows the passage of silicone oil. In the oil application amount control layer 16b of this embodiment, a stretched polytetrafluoroethylene (PTFE) porous membrane (hereinafter, PT
FE porous membrane). The oil application amount control layer 16b is bonded to an oil transfer layer 16a formed on the outer periphery of the oil holding member 15 with a mixture of an adhesive and silicone oil, and the mixture is sufficiently mixed. It is important that they are distributed
The mixture is applied to the entire outer peripheral surface of the oil transfer layer 16a, and the oil application amount control layer 16b is wound and adhered to the applied surface. That is, the entire surface of the oil application amount control layer 16b that is in contact with the entire outer peripheral surface of the oil transfer layer 16a is bonded with the mixture. This adhesive coexists with silicone oil,
There is no particular limitation as long as the oil transfer layer 16a and the oil application amount control layer 16b can be bonded. In this embodiment, a silicone varnish is used as an adhesive, and the mixing ratio of the silicone varnish (SW) and the silicone oil (SO) is 99: 1 to 20:80 (SW: SO = 99: 1 to 1).
20:80).

Next, a method of using the oil application roller 8 having the above configuration will be described. First, the plug (not shown) of the release oil supply port of the oil application roller 8 is removed, and the silicone oil 153 is injected and filled into the hollow portion 152 from the release oil supply port and plugged. Since the silicone oil 153 filled in the hollow portion 152 is temporarily held by the oil holding member 15, it hardly leaks outside during transportation and storage of the oil application roller 8. The oil application roller 8 is incorporated in the fixing device 10 and used. The oil application roller 8 applies a sufficient amount of silicone oil 153 from the hollow portion 152 to the porous oil holding member 15.
1, it is possible to widen the adjustment range of the oil application amount, and to apply the silicone oil 153 to the peripheral surface of the heat-fixing roll 11 that is in contact with the oil fixing layer 11 evenly through the oil application layer 16. Can be. Therefore, in order to fix the toner 13 transferred to the surface 9 a of the recording paper 9, the toner 13 passes through the recording paper 9 between the heat-fixing roll 11 and the pressure roll 12.
Does not adhere to When the silicone oil 153 is continuously applied to the heat fixing roll 11, the amount of the silicone oil 153 in the hollow portion 152 is reduced, and an air layer 152a is formed. Further, the cut 3 of the pressure relief valve 1 is so small that no gap is observed, and the portion may be swollen with silicone oil. Never leak.

When the temperature of the oil application roller 8 rises while the fixing device 10 is in use, the air layer 152a and the silicone oil 153 thermally expand and the pressure in the hollow portion 152 rises. This pressure is usually in the range of 1-30 KPa gauge pressure. In this case, the four pieces 4 of the pressure relief valve 1 are pushed to the outside air side to create a slight gap and reduce the rising pressure to the atmosphere. Accordingly, it is possible to prevent an excessive amount of oil from being applied from the outer peripheral surface of the oil applied amount control layer 16b due to a rise in the pressure in the hollow portion 152.

Next, another oil applying apparatus according to the present invention will be described with reference to FIG. FIG. 7 is a cross-sectional view as viewed from the end surface of the heat fixing roll 11. 7, an oil application device 8
a, an oil coating layer 16 is provided on the lower outer periphery of a silicon oil holding member 151 made of a porous molded body attached to a front corner of the bottom of the silicon oil storage tank 21 and held by the silicon oil holding member 151. The release oil 153 is supplied to the fixing roll 11, the release oil 153 is injected into the silicon oil storage tank 21, and the top plate 212 between the gas phase portion 211 of the silicon oil storage tank 21 and the outside air is supplied. And a pressure relief valve 1 attached thereto.
Silicon oil holding member 151 and oil application layer 16
Is similar to that used in the oil application roller 8 of FIG. 5 except that the shape is different. That is, the shape of the silicon oil holding member 151 is obtained by cutting the hollow cylindrical silicon oil holding member used in FIG. 5 into a quarter sectional view, and the oil application layer 16 is reversed inside the silicon oil holding member, ie, It is attached to the side with the smaller curvature. The curvature of the outermost oil application amount control layer 16b is formed so that the peripheral surface of the heat-fixing roll 11 abuts. In addition, the silicon oil storage tank 21 does not need to be a porous molded body, but can be made of metal. As the pressure release valve 1 used in the oil application device 8a, the pressure relief valve 1 of the first embodiment can be used. The oil application device 8a configured as described above can apply a large amount of release oil to the heat fixing roll 11, and is suitable for an oil application device that requires a large amount of release oil to be applied due to the characteristics of the toner. is there.

Next, a method of using the oil application roller 8a having the above configuration will be described. First, the plug (not shown) of the release oil supply port of the oil application roller 8a is removed, and the silicone oil 153 is injected and filled into the silicon oil storage tank 21 from the release oil supply port, and is plugged. The oil application roller 8a is used by being incorporated into the fixing device 10. The oil application roller 8a can supply a sufficient amount of silicone oil 153 from the silicone oil storage tank 21 to the porous oil holding member 15. Furthermore, the silicone oil 153 can be applied to the peripheral surface of the heat-fixing roll 11 that is in contact with the oil-fixing layer 16 evenly through the oil application layer 16. Therefore, the toner transferred to the surface of the recording paper is fixed, so that the toner does not adhere to the heat fixing roll 11 even if the recording paper is passed between the heat fixing roll and the pressure roll. If the silicone oil 153 is continuously applied to the heat fixing roll 11, the silicone oil storage tank 21
The silicon oil 153 inside is reduced, and the air layer 211a is formed.

When the temperature of the oil application roller 8a rises during use of the fixing device 10, the air layer 211a and the silicone oil 153 thermally expand, and the pressure in the silicone oil storage tank 21 rises. This pressure is usually 1 to
It is in the pressure range of 30 KPa. In this case, the pressure relief valve 1
The four pieces 4 are pushed to the outside air side to create a slight gap and reduce the rising pressure to the atmosphere. As a result, the oil application amount control layer 16b accompanying the pressure increase in the hollow portion 211
Can be prevented from being applied with an excessive amount of oil from the outer peripheral surface.

[0033]

Next, the present invention will be described in more detail with reference to examples, but this is merely an example and does not limit the present invention.

Examples 1 to 9 and Comparative Examples 1 to 4 FIGS. 5 and 6 show an oil application roller 8 and a pressure release valve 1 of Example 1. FIG. (Production of oil holding member) 100 parts by weight of E glass fiber having an average fiber diameter of 15 μm and an average fiber length of 3000 μm, 50 parts by weight of silica alumina fiber having an average fiber diameter of 15 μm and an average fiber length of 200 μm, and polyethylene resin particles 70 having an average particle diameter of 200 μm 100 parts by weight of colloidal silica as an inorganic binder, 20 parts by weight of methylcellulose functioning as an organic binder, and 100 parts by weight of water were kneaded to obtain a kneaded product. Next, this kneaded material was extruded to obtain a hollow cylindrical molded body having an axial length of 300 mm, a diameter of 33 mm, and a hollow portion having a diameter of 23 mm. This hollow cylindrical molded body is
It was dried at 5 ° C. for 2 hours and fired at 480 ° C. for 8 hours. In the fired product, water and methylcellulose in the cylindrical molded body are vaporized by the drying step and the firing step to form interfiber voids having a main diameter distribution of 10 to 100 μm, and polyethylene resin particles are burned out. It was a porous ceramic having large pores having a diameter of 200 μm. The oil holding member 15 is made of such porous ceramics so that the airflow resistance is 0.07 MPa · s / m ³ .

(Manufacture of pressure release valve) A silicon rubber pressure release valve having the characteristics shown in Table 1 was prepared. There were four holes, and a cross was cut with a sharp cutter as shown in FIG. In Table 1, "hardness" is a value measured after immersing in silicon oil having a kinematic viscosity of 100 cSt at 170 ° C. for 72 hours to swell.

(Manufacture of Oil-Applying Roller) First, aramid fiber having an average fiber diameter of 10 μm and an average fiber length of 5 mm was coated to a thickness of 2 mm.
mm, a felt processed into a ribbon shape having a basis weight of 300 g / m ² and a width of 30 mm are spirally formed from one end side to the other end side of the oil holding member 1 so as to cover the entire outer peripheral surface of the oil holding member 15. It was wound and fixed. At this time, RTV rubber is partially applied to the surface of the oil holding member 15 and adhered to felt to form an oil transfer layer 16 having a thickness of 2 mm.
a was formed. Next, a mixture of a silicone varnish having a viscosity of 1000 cSt at 25 ° C. and a silicone oil having a viscosity of 300 cSt at 25 ° C. mixed at a weight ratio of 80:20 is used to form a stretched PTFE membrane having an air permeability of 1,300 KPa · s / m ^2. Was applied on the entire inner peripheral surface at a surface density of 50 g / m ² , and an expanded PTFE film was adhered to the felt peripheral surface to form an oil applied amount control layer 16b having a thickness of 150 μm. The adhesive portion at the interface between the oil transfer layer 16a and the oil application amount control layer 16b is a material in which only the silicone varnish dispersed in the silicone oil is dispersed at the molecular level and cured and adhered. Because of having a porous structure, silicone oil was permeable. Next, a metal flange as shown in FIG. 6 was produced, and an oil application roller 8 as shown in FIG. 5 was produced. The thickness of the flange is 0.5 to 1.2.
mm, the pressure relief valve was installed on the flange with an adhesive. The obtained oil application roller 8 was obtained by impregnating the oil holding member 15 with silicone oil for release under a reduced-pressure atmosphere. The impregnation amount was half the amount in the hollow part. The oil application roller 8 was provided with a pressure sensor (AP-40; KEYENCE) for measuring the pressure in the hollow portion on the flange surface.

(Observation of Heat Leakage) The oil application roller 8 impregnated with silicone oil was placed in a constant temperature bath at 170 ° C., and after one hour from normal temperature, it was taken out and observed for heat leakage. In Table 1, "A" indicates the presence or absence of release oil leakage from the pressure release valve 1, and "B" indicates the presence or absence of release or leakage of the PTFE film from the PTFE film surface. The release oil leak refers to a leak such as dripping from the oil application roller 8, and wetting on the PTFE film surface is not observed as a leak. Table 1 shows the results. According to Table 1, when the pressure in the hollow portion is 40 KPa or more, the PTFE membrane swells and peels off.

[0038]

[Table 1]

REFERENCE EXAMPLE In the pressure relief valve used in the embodiment, the diameter is 5 mm, the hardness of the silicone rubber is 35, and the silicone rubber constituting the pressure relief valve and the valve open in a state of swelling with silicone oil. The relationship between the pressure (valve opening pressure) and the one side (hollow portion) of the pressure release valve is air and the other side (atmosphere) is air. Silicone oil (100 cSt at 25 ° C)
Then, the case where the other side (atmosphere) was air was examined as a parameter. FIG. 8 shows the results.

As shown in FIG. 8, as the thickness of the silicone rubber constituting the pressure relief valve increases, the valve opening pressure increases. Also, when both sides of the pressure relief valve are in contact with air,
0.8mm thick silicone rubber that composes pressure relief valve
Even if it is thick, the valve opening pressure is only about 11 kPa. That is, the valve opens with a small gauge pressure difference of about 11 kPa, and the internal pressure escapes. On the other hand, if the hollow side is in contact with the silicone rubber even with the same pressure relief valve, the valve will not open unless there is a large gauge pressure difference of 38 kPa. This means that in the pressure relief valve of the present invention,
It can be seen that there is a large difference in the pressure difference at which the valve opens between the state where the valve is in contact with the silicone oil and swells and the state where the valve is not in contact with the silicone oil. The present invention makes use of this fact to give selectivity to the pressure value at which the valve opens, depending on whether the object that the valve opens is air or silicone oil. That is, the same pressure release valve is structured such that the valve is not opened when it is in contact with the silicone oil, and the valve is opened when it is in contact with the air layer, so that the pressure can be released. With such a structure, it is possible to obtain a function as a safety valve that does not leak oil from the pressure release valve and selectively allows only the pressurized air to escape to the outside.

[0041]

According to the present invention (1), for example, if the pressure release valve is attached to the top plate of the silicone oil storage tank of the pad type oil application device, the silicone oil or air is heated by the fixing roller. Even if the pressure in the gas phase of the silicon oil storage tank rises due to thermal expansion, the pressure is released to the outside air by the action of the pressure release valve. Evils such as leakage can be prevented.

According to the present invention (2), for example, if the pressure relief valves are provided at the flange portions provided at both ends of the hollow cylindrical silicone oil holding member of the oil application roller, the heating from the fixing roller can be achieved. Due to the thermal expansion of silicon oil and air, the pressure of the gas phase in the hollow increases,
Due to the action of the pressure release valve, the pressure is released to the outside air, and adverse effects such as excessive application of silicone oil and oil leakage due to a rise in pressure in the gas phase can be prevented. In addition, the pressure relief valve has a minute cut through the front and back surfaces, and has a closing effect of the cut portion due to swelling of the silicon oil, so that the pressure release valve is immersed in the silicon oil filled in the hollow portion. Also, no silicone oil leaks from the pressure release valve.

According to the present invention (3), the above (2)
The same effects as those of the described invention can be obtained. The present invention (4)
According to this, it is possible to easily determine a suitable pressure release valve suitable for the properties of the silicone oil holding member of the oil application roller, the properties of the rubbers, and the like. Further, according to the present invention (5), the same effect as described in the above (1) is exhibited particularly in a pad-type oil application device provided with a silicone oil storage tank. According to the present invention (6), in particular, the same effect as described in the above (2) can be obtained in the oil application roller.

[Brief description of the drawings]

FIG. 1 is a perspective view of a pressure relief valve according to a first embodiment.

FIG. 2 is a view for explaining an operation state of a pressure relief valve of FIG. 1;

FIG. 3 is a schematic diagram of an apparatus for measuring air permeability.

FIG. 4 is a side view showing an installation state of an oil application roller using a hollow cylindrical silicone oil holding member in a fixing device.

FIG. 5 is an axial sectional view of an oil application roller equipped with a pressure release valve.

FIG. 6 is a perspective view of a flange portion provided with a pressure relief valve of the present example.

FIG. 7 is a radial cross-sectional view of another oil application device equipped with a pressure release valve.

FIG. 8 is a diagram showing the relationship between the opening pressure of a valve and the thickness of a pressure relief valve in a reference example.

FIG. 9 is an axial sectional view showing a conventional example.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 pressure relief valve 2 rubber-like sheet material 3 cut 4 piece 5 partition wall 8, h oil application roller 8 a oil application device 9 recording paper 9 a surface 10 fixing device 11 heat fixing roll 12 pressure roll 13 toner 15 hollow Cylindrical silicon oil holding member 16 Oil coating layer 16a, c Oil transition layer 16b, d Oil coating amount control layer 18 Flange 19 Shaft 152, 211 Hollow portion 153, g Silicon oil (release oil) 152a, 211a, i Air layer f Oil holding tank

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court II (Reference) // B05C 11/11 B05C 11/11 (72) Inventor Seiki Ono 1-1, Shibadaimon, Minato-ku, Tokyo 26 Inside Nichias Corporation (72) Inventor Tsuyoshi Kuboyama 1-8-1 Shintoda, Hamamatsu-shi, Shizuoka Prefecture Nichias Inside Hamamatsu Research Laboratories Co., Ltd. (72) Munehiko Fukase 1-8-1 Shintoda, Hamamatsu-shi, Shizuoka Nichiasu F-term in Hamamatsu Laboratory Co., Ltd. (reference) 2H033 AA09 BA42 BA43 3H055 AA11 BA01 BA18 CC05 CC11 CC21 GG01 3J103 AA02 BA46 CA05 FA22 GA02 GA57 GA58 HA01 HA53 4F040 AA05 AB08 BA07 BA14 CA02 CB02 CB05 CB28 4F042 AA03 BA04 DE01 DF03 DF32

Claims (6)

[Claims] 1. A rubber sheet having a hardness of 10 to 80, which is attached to a partition wall for partitioning the outside air and the pressure adjusting chamber, wherein the rubber sheet has a cut through the front and back surfaces. The pressure adjustment chamber has a gauge pressure of 1 to 1
A pressure relief valve that opens at a pressure of 00KPa. 2. A rubber-like sheet having a hardness of 5 to 50, which is attached to a hollow portion of a hollow cylindrical silicone oil holding member made of a porous molded body and a flange for partitioning outside air, and has a hardness of 5 to 50 after swelling of silicone oil. A pressure relief valve characterized in that the rubber sheet is formed with cuts penetrating the front and back surfaces, and the pressure adjusting chamber is opened at a pressure of 1 to 30 KPa. 3. The pressure relief valve according to claim 2, wherein the hollow cylindrical silicon oil holding member made of the porous molded body is a silicon oil holding member of an oil application roller. 4. The rubber-like sheet material is a disk-shaped silicone rubber attached to a part of the flange, and has a thickness of 0.3 to 2.0 mm and a diameter of 3.0 to 6.0 mm. The pressure relief valve according to claim 2 or 3, wherein 5. An oil coating layer is provided on an outer periphery of a lower portion of a silicone oil holding member made of a porous molded body attached to the bottom of a silicone oil storage tank, and the release oil held by the silicone oil holding member is fixed to a fixing roll. 2. The pressure relief valve according to claim 1, wherein a release oil is injected into the silicon oil storage tank, and a release plate is provided between the gas phase portion of the silicon oil storage tank and the outside air. An oil application device characterized by being provided with: 6. An oil application roller provided with an oil application layer on the outer periphery of a hollow cylindrical silicone oil holding member made of the porous molded body, and supplying release oil held by the oil holding member to a fixing roll. Wherein the pressure-relieving valve according to any one of claims 2 to 4 is provided on a flange portion which is filled with a release oil in the hollow portion and which separates the hollow portion from the outside air. And an oil application roller.