JP2002278340A - Oil coating applicator, oil coating application roller and method of manufacturing oil coating application roller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of a high-temperature offset in non-paper passage regions near both ends of a fixing roller. SOLUTION: This oil coating applicator has an oil coating application roller 24 which is brought into pressurized contact with the outer peripheral surface of the fixing roller 41 for fixing a toner image to a recording material and applies a silicone oil to this fixing roller 41 and an oil regulating blade 31 which abuts on the oil coating application roller 24 along the longitudinal direction of the oil coating application roller 24. The silicone oil flows along a first lading up roller 22 and a second lading up roller 23 from an oil pan 21 and is supplied to the oil coating application roller 24. The oil coating application roller 24 has an arbor 24a of an inverted crown shape of the external diameter increasing gradually from the central part toward both ends along the longitudinal direction and a silicone rubber layer 24B which is disposed on the outer peripheral surface of the arbor 24a and has the outer peripheral surface of the crown shape of the external diameter continuously decreasing from the central part toward both ends along the longitudinal direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil applying apparatus for applying silicone oil as a releasing oil to the surface of a fixing roller of a thermal fixing apparatus in an electrophotographic copying machine, a laser beam printer, or the like. The present invention relates to a roller and a method for manufacturing the oil application roller.

[0002]

2. Description of the Related Art In an electrophotographic process represented by an electrophotographic copying machine, a toner image on a recording material is fixed on the recording material by a heat roller fixing device. In this heat roller fixing device, a fixing roller and a pressure roller are arranged to face each other, and a tubular heating heater such as a halogen lamp is provided.
For example, it is arranged on the central axis of the fixing roller. The heat generated from the halogen lamp is uniformly radiated to the inner wall of the fixing roller, and the temperature distribution on the outer wall of the fixing roller becomes uniform in the circumferential direction. The outer wall of the fixing roller is heated until its temperature reaches a temperature suitable for fixing (for example, 150 to 200 ° C.). In this state, the fixing roller and the pressure roller rotate in opposite directions to each other while being pressed against each other, and sandwich the recording material holding the toner. At the nip where the fixing roller and the pressure roller are in pressure contact, the unfixed toner on the recording material is melted by the heat conducted from the fixing roller, and the pressure acting on both rollers is further applied to fix the toner on the recording material. You.

In the heat roller fixing device for performing such a fixing method, since the surface holding the toner among the both surfaces of the recording material is in direct contact with the surface of the fixing roller, a part of the unfixed toner image on the recording material is formed. Is easily transferred to the fixing roller side.
For this reason, the toner fused to the fixing roller is transferred to the rear end of the recording material again and soils the recording material, or re-transferred to the next transported recording material and soils the recording material. However, there is a disadvantage that a so-called toner offset phenomenon easily occurs. Therefore, the heat roller fixing device has means for applying a releasing oil for preventing toner offset to the fixing roller. Silicone oil is used as the release oil.

As means for applying the silicone oil to the fixing roller, means for applying the silicone oil to the surface of the fixing roller with a web or felt impregnated with silicone oil, or applying an oil application roller containing silicone oil to the surface of the fixing roller There is known a means for applying a coating by directly contacting the coating. However, when it is required to apply a lot of silicone oil like a printer that records color images,
An oil application unit using an oil application roller is more preferably used than an oil application unit using a web or felt.

[0005] In the case of using an oil applying means by an oil applying roller, in order to regulate the amount of silicone oil on the oil applying roller, the oil applying roller is brought into contact with the oil applying roller by a spring so as to maintain a constant pressure. Conventionally, means for directly contacting an oil regulating blade made of an elastic body with the surface of an oil application roller has been used. Fluororubber is used as the elastic material of such an oil regulating blade.

For the production of the oil application roller, molding methods such as extrusion molding and die molding (compression molding, transfer molding, casting) have been conventionally used.

[0007]

In the above-described heat roller fixing device, it is preferable to make the temperature distribution in the longitudinal direction of the fixing roller as uniform as possible. However, such control is difficult in practice. For example, if the width of the recording material passed through the fixing roller is smaller than the length of the fixing roller, heat is accumulated on the roller surface (non-sheet passing area) of the fixing roller through which the recording material does not pass, and the temperature of the fixing roller is reduced. Temperature rises abnormally. The temperature unevenness between the non-sheet passing area and the sheet passing area of the fixing roller appears remarkably when the recording material continuously passes through the fixing roller. At this time, if the heating temperature of the fixing roller is set so that the temperature of the paper passing area becomes a predetermined temperature, a phenomenon occurs that the temperature of the non-paper passing area becomes extremely high (hereinafter, this is referred to as "non- This is referred to as “paper passing area temperature increase”). Then, when the recording material is switched to a larger size, for example, a recording material having a width substantially equal to the length of the fixing roller after the non-sheet passing area temperature rises, Since the temperature of the area where the small-sized recording material that had been processed up to now was not in contact was too high, a so-called high-temperature offset sometimes occurred in that area.

As a means for solving this problem, means for providing a plurality of heat generating patterns on the fixing roller and energizing only a region through which the recording material passes according to the size of the recording material (Japanese Patent Laid-Open No. 5-134575, Japanese Patent Publication No. Hei 5-134575). 7-1095
No. 31, JP-A No. 7-36303, and JP-A No. 10-11, in which a high heat conductive layer is provided below a releasing layer of a fixing roller to make the temperature distribution in the roller axis direction uniform.
No. 5991) has been proposed. But,
Each of these means requires a complicated apparatus configuration and control method, and thus the apparatus itself becomes expensive.

As another solution, there has been proposed a method of preventing the local rise in the temperature of the fixing roller by increasing the interval between the recording materials so as to be longer than the normal interval between the continuous passes. But,
In this method, there is a problem that the printing speed becomes slow and printing takes a very long time.

Further, as another solution, there is a means using an oil application roller formed in a crown shape whose outer diameter continuously decreases from a central portion to both ends along a longitudinal direction. As a method of manufacturing such a crown-shaped oil application roller, a silicone rubber material is vulcanized and bonded to the outer peripheral surface of a cored member subjected to an adhesive treatment by compression molding, transfer molding, or the like to form a silicone rubber layer. Then, a method of grinding the outer peripheral surface of the oil application roller into a crown shape is known. But,
In such a method, a step of grinding the surface of the silicone rubber layer is indispensable, and it has been difficult to finish the surface roughness of the roller to a desired accuracy.

Another method of manufacturing a crown-shaped oil application roller is to form a through-hole in a mold with a drill or the like, and cut and honing the inner surface of the hole to finish the crown-shaped mold. The core metal member is inserted into the hole, and both ends of the metal core member are fixed to the molds with the lids, and then the gap between the mold and the metal core member is filled with a silicone rubber material and then vulcanized. A method is known in which a silicone rubber layer is formed on the outer peripheral surface of a cored member. However, in such a method, the inner surface of the hole that is longer in the axial direction than the inner diameter of the mold must be cut and honed to finish the inner surface in a crown shape. It was difficult to finish with high precision to obtain a shape.

Still another method of manufacturing a crown-shaped oil applying roller is to insert a straight cylindrical core member into a straight cylindrical (constant inner diameter) hole formed in a mold, and to insert the core into the hole. Both ends of the metal member are fixed to the mold with lids, and then a gap between the mold and the core member is filled with a silicone rubber material and vulcanized. At this time, along the longitudinal direction of the core member There is known a method in which the temperature of a mold is changed to change the promotion of vulcanization by heat to form a silicone rubber layer so as to have a crown shape after demolding. According to this method, it is not necessary to finish the hole of the mold in a crown shape, but it is difficult to stabilize the shape of the silicone rubber layer after demolding because the environment is highly dependent upon vulcanization. Therefore, there is a problem that the molding time becomes longer because there is a part to be vulcanized.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an oil application device and an oil application roller that can prevent a high-temperature offset from occurring in a non-sheet passing area near both ends of a fixing roller.

It is another object of the present invention to provide a method of manufacturing an oil application roller that can easily and inexpensively manufacture the above-mentioned oil application roller.

[0015]

In order to achieve the above-mentioned object, an oil applying apparatus according to the present invention comprises an oil applying apparatus for applying a releasing oil to an outer peripheral surface of a fixing roller for fixing a toner image on a recording material. Has an oil retaining layer having a crown-shaped outer peripheral surface whose outer diameter continuously decreases from a central portion to both ends along a longitudinal direction, and for applying the releasing oil to the fixing roller. An oil application roller that is pressed against the fixing roller, and an oil regulating blade that contacts the oil application roller along the longitudinal direction of the oil application roller.

According to the oil applying device of the present invention, since the oil applying roller is formed in a crown shape, the contact pressure of the oil regulating blade against the oil applying roller is increased along the longitudinal direction of the oil applying roller. It gradually decreases from the center toward both ends. Therefore, the amount of the releasable oil contained in the oil holding layer of the oil application roller handled by the oil regulating blade is greatest at the center of the oil application roller, and gradually decreases toward both ends.
Therefore, the amount of the releasable oil contained in the oil holding layer of the oil application roller is smallest at the center and gradually increases toward both ends. As a result, more releasable oil is applied to the fixing roller from the center in the longitudinal direction of the oil applying roller toward both ends, and the non-paper passing area generated near both ends of the fixing roller is heated. The accompanying high-temperature offset is prevented from occurring.

Further, the oil applying roller is provided with an oil retaining layer on an outer peripheral surface of an inverted crown-shaped core metal whose outer diameter continuously increases from a central portion to both ends along a longitudinal direction thereof. By having the configuration, the difference in thickness of the oil holding layer between the center and both ends of the oil application roller becomes larger, and in the longitudinal direction of the oil application roller, the amount of release oil contained in the oil holding layer, As a result, the distribution gradient of the amount of release oil applied to the fixing roller can be made larger, and the occurrence of high-temperature offset due to the temperature rise in the non-sheet passing area near both ends of the fixing roller can be more effectively prevented. Can be prevented.

Further, the oil holding layer may be made of silicone rubber, and the release oil may be silicone oil.

Further, the oil application roller of the present invention has an inverted crown-shaped core metal whose outer diameter continuously increases from the center to both ends in the longitudinal direction, and is provided on the outer peripheral surface of the core. An oil retaining layer having a crown-shaped outer peripheral surface whose outer diameter continuously decreases from a central portion to both ends along a longitudinal direction.

According to the oil application roller of the present invention,
The difference in thickness of the oil holding layer between the center and both ends of the oil applying roller can be increased, and the amount of release oil contained in the oil holding layer in the longitudinal direction, and hence the release property applied to the fixing roller. It is possible to increase the distribution gradient of the oil amount. As a result, the amount of release oil applied to the fixing roller near both ends of the oil application roller increases, and the occurrence of a high-temperature offset due to a temperature rise in the non-sheet passing area near both ends of the fixing roller is effectively prevented. Can be prevented.

Further, the oil holding layer may be made of silicone rubber.

The method for manufacturing an oil application roller according to the present invention is also directed to an oil application roller having an oil holding layer formed in a crown shape whose outer diameter continuously decreases from a central portion to both ends along a longitudinal direction. A method of manufacturing a roller, wherein the outer surface of the oil retaining layer is a straight cylinder on the outer peripheral surface of an inverted crown-shaped core metal whose outer diameter continuously increases from a central portion to both ends along a longitudinal direction. Forming an oil applying roller intermediate body that is formed so as to have a shape, and wherein the thickness of the oil retaining layer continuously decreases from the central portion to both ends along the longitudinal direction; and Immersing the body in swelling oil, impregnating the swelling oil in the oil retaining layer,
It is characterized by having.

As a result, a crown-shaped oil application roller in which the thickness difference between the oil holding layers at the center and both ends in the longitudinal direction is increased can be manufactured simply and inexpensively.

Further, the oil holding layer may be made of silicone rubber, and the swelling oil may be silicone oil.

[0025]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic view showing an embodiment of an oil application device for applying silicone oil to a fixing roller of a heat roller fixing device.

The oil application device according to the present embodiment includes an oil pan 21 containing silicone oil as release oil.
And a first pumping roller 2 in which at least a part of an outer peripheral surface is immersed in silicone oil in an oil pan 21.
2, a second pumping roller 23 arranged so that its outer peripheral surface is in contact with the outer peripheral surface of the first pumping roller 22;
An oil application roller 24 is provided so that the outer peripheral surface is in contact with the outer peripheral surface of the second pumping roller 23. Further, the fixing roller 41 is moved from the oil application roller 24 to the fixing roller 41.
An oil regulating blade 31 for limiting the amount of oil supplied to the oil application roller 24 is in contact with the surface of the oil application roller 24 by a spring or the like. Each of the rollers 22, 23, and 24 has a porous surface, for example, so that it can adsorb silicone oil.

When applying silicone oil to the fixing roller 41 of the heat roller fixing device, the oil application roller 24 is pressed against the fixing roller 41 (only a part of the fixing roller 41 is shown in the figure) as shown in the figure. Can be The rollers 22, 23, 24, and 41 are arranged such that their rotation center axes are parallel to each other, and when at least one of the rollers is rotated, the remaining rollers are driven to rotate. Have been.

In the oil applicator configured as described above, the applied oil stored in the oil pan 21 is transferred from the first pumping roller 22 to the second pumping roller 23.
Further, the oil is supplied from the second pumping roller 23 to the oil application roller 24 via the respective rollers. The silicone oil supplied to the oil application roller 24 is applied to the fixing roller 41 after excess oil is removed by the oil regulating blade 3 contacted by a spring.

FIG. 2 is a longitudinal sectional view of the oil application roller shown in FIG.

As shown in FIG. 2, the oil application roller 24 according to the present embodiment has an inverted crown-shaped aluminum core metal whose outer diameter continuously increases from the center to both ends in the longitudinal direction. 24a, and a silicone rubber layer 24b as an oil holding layer provided around the periphery thereof so as to have a crown shape.

Here, the outline of the manufacturing process of the oil application roller 24 will be described.

First, a primer treatment for applying and baking a silicone rubber primer is performed on the peripheral surface of the inverted crown-shaped aluminum core 24a. Then, the core metal 24a is inserted into a mold having a cavity of a right cylindrical shape, and both ends thereof are fixed with lids having support holes. Then, silicone rubber is injected into the mold, and the silicone rubber is cured by heating with a heating device, and then is taken out of the mold. Then, the silicone rubber layer 24 whose outer peripheral surface is formed in a right cylindrical shape
An oil application roller intermediate having b is obtained. next,
This oil application roller intermediate is immersed in silicone oil, and the silicone rubber layer 24b is impregnated with silicone oil, whereby the silicone rubber layer 24b swells and an oil application roller having a crown-shaped outer peripheral surface is finally obtained. In this way, the crown-shaped oil application roller 24 in which the difference in thickness of the silicone rubber layer 24b between the central portion and both ends in the longitudinal direction is increased is manufactured simply and inexpensively.

The silicone rubber mainly contained in the silicone rubber layer 24b of the oil application roller 24 may be any of an addition-reaction cross-linkable silicone rubber, a condensation-reaction cross-linkable silicone rubber, and an organic peroxide crosslinked silicone rubber. It may be.

According to the oil application device of the present embodiment configured as described above, since the oil application roller 24 is formed in a crown shape, the oil application roller 24
Of the oil regulating blade 31 gradually decreases from the center to both ends along the longitudinal direction of the oil application roller 24. Therefore, the amount of the silicone oil contained in the silicone rubber layer 24b of the oil application roller 24 handled by the oil regulating blade 31 is greatest at the center of the oil application roller 24, and gradually decreases toward both ends. Therefore, the amount of the silicone oil contained in the silicone rubber layer 24b of the oil application roller 24 is the smallest at the center and gradually increases toward both ends. As a result, more silicone oil is applied to the fixing roller 41 from the center in the longitudinal direction of the oil application roller 24 to both ends, and the non-paper passing area generated near both ends of the fixing roller 41 is heated. Is prevented from occurring due to the high temperature offset.

The oil application roller 24 is provided with a silicone rubber layer 24b on the outer peripheral surface of an inverted crown-shaped core metal 24a whose outer diameter continuously increases from the center to both ends along the longitudinal direction. With this configuration, the thickness difference of the silicone rubber layer 24b between the center and both ends of the oil application roller 24 is larger. Therefore, in the longitudinal direction of the oil application roller 24, the distribution gradient of the amount of silicone oil contained in the silicone rubber layer 24b, and hence the amount of silicone oil applied to the fixing roller 41, can be further increased, and the fixing roller It is possible to more effectively prevent the occurrence of a high-temperature offset due to a rise in the temperature of the non-sheet passing area near both ends of the sheet 41.

[0037]

An embodiment of the oil application roller described above will be described below.

Referring to FIG. 2, the core metal 24a of the oil application roller 24 of this embodiment has an outer diameter of 26 mm at both ends.
The outer diameter at the center is 24mm, and the amount of reverse crown is 1.0mm
Is an aluminum core having an inverted crown shape.

The manufacturing process of the oil application roller 24 of this embodiment will be described with reference to FIG.

In manufacturing the oil application roller 24,
First, a primer for addition reaction crosslinked silicone rubber (Primer No. 101, manufactured by Shin-Etsu Chemical Co., Ltd.) is applied to the surface of the cored bar 24a, and the primer is placed in a hot air oven at 200 ° C. for 1 hour. The gold 24a was subjected to a primer treatment for baking (see FIG. 3A).

Subsequently, the obtained cored bar 24a is
In a cylindrical mold having an inner diameter of 30 mm and a cavity of a straight cylindrical shape formed therein, the support hole is formed so as to be concentric with the mold and directly contact the upper and lower side surfaces of the cored bar 24a. 24 metal cores with two lids (caps)
a was fixed.

Then, the cylindrical mold is arranged so that its longitudinal direction is vertical, and an addition-reaction crosslinked silicone rubber (Toray Co., Ltd.) is inserted into the mold from the gap between the lower cap and the mold.
DY35-44, manufactured by Dow Corning Silicone Co., Ltd.
6) was injected, and the space between the cylindrical mold and the core metal 24a was filled without any gap. Under the condition of 150 ° C for 30 minutes,
It was cured by heating in hot air. After heating, the core metal 24a has a silicone rubber layer 24b provided on the outer periphery of the core metal 24a.
Was taken out of the mold and heated at 200 ° C. for 4 hours to secondary vulcanize the silicone rubber.

Thus, the thickness of the end portion of the roller is 2.0 mm and the thickness of the center portion of the roller is 3.0 mm on the cored bar 24a.
Thus, an oil application roller intermediate having a silicone rubber layer 24b whose thickness was continuously reduced from the center toward both ends was obtained (see FIG. 3B). Note that the intermediate surface of the oil application roller in this state has a straight cylindrical shape on the outer peripheral surface.

Next, the intermediate oil application roller in this state was replaced with dimethyl silicone oil (KF96S manufactured by Shin-Etsu Silicone Co., Ltd.) as a silicone oil for immersion.
S, 100CS) at 120 ° C. for 24 hours to impregnate the silicone rubber layer 24b with the silicone oil in the most surface-side region, thereby obtaining the silicone rubber layer 24b.
Roller 2 having a bulging outer surface and a crown shape
4 was finally obtained (see FIG. 3 (c)). The crown amount of the obtained oil application roller 24 was 0.1 mm.

Next, the oil application roller 24 obtained in the present embodiment was mounted on an oil application device in an image forming apparatus (not shown), and a screen passing test was performed. The outline of the image passing test is as follows.

First, among several paper feed trays of the image forming apparatus, 100 sheets of A5 size paper are fed to one A4 paper feed tray so as to be located at the center thereof, and the other A4 paper is fed. A4 size recording material is fed to a size paper feed tray. Then, 100 sheets of A5 size paper on which an image (single-color solid image) in which a single-color toner is uniformly placed on the recording surface of the recording material is continuously formed on the fixing roller of the image forming apparatus. After that, immediately after that, an A4 size recording material on which a single-color solid image is formed is passed.

As a result of examining the fixed image recorded on the A4-size recording material, no abnormality such as high-temperature offset was observed in the non-sheet-passing area of the fixing roller when the A5-size recording material was passed. The fixed image was good.

(Comparative Example) As a comparative example with respect to the above-described embodiment, as shown in FIG. 4, a silicone rubber layer 1 was formed on the outer peripheral surface of a straight cylindrical aluminum core bar 100a having an outer diameter of 26 mm.
00b is an oil application roller 1 provided in a right cylindrical shape
00, an image passing test was performed in the same manner as in the above embodiment.

As a result of examining the fixed image recorded on the A4 size recording material, a high-temperature offset occurs in the non-sheet passing area of the fixing roller when the A5 size recording material is passed, and an image defect occurs in the fixed image. Had occurred.

[0050]

As described above, the oil applicator of the present invention has an oil holding layer having a crown-shaped outer peripheral surface, and is pressed against the fixing roller to apply release oil to the fixing roller. The oil application roller and an oil regulating blade that contacts the oil application roller along the longitudinal direction of the oil application roller, so that more release oil can be applied near both ends of the fixing roller. Thus, it is possible to prevent high-temperature offset from occurring in the non-sheet passing areas near both ends of the fixing roller.

Further, since the oil application roller of the present invention has an inverted crown-shaped cored bar and an oil holding layer having a crown-shaped outer peripheral surface, the oil is applied to the fixing roller from near both ends of the oil application roller. The amount of the release oil is increased, and it is possible to more effectively prevent the occurrence of the high-temperature offset due to the temperature rise in the non-sheet passing area near both ends of the fixing roller.

Further, according to the method of manufacturing an oil application roller of the present invention, an oil retaining layer is formed on the outer peripheral surface of a core metal having an inverted crown shape so that the outer peripheral surface has a right cylindrical shape, and the thickness of the oil retaining layer is reduced. A step of forming an oil application roller intermediate that is continuously reduced from the center to both ends along the longitudinal direction; and And thus a crown-shaped oil application roller in which the difference in thickness of the oil holding layer between the central portion and both end portions in the longitudinal direction is increased can be simply and inexpensively manufactured.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an embodiment of an oil application device for applying silicone oil to a fixing roller of a heat roller fixing device.

FIG. 2 is a longitudinal sectional view of the oil application roller shown in FIG.

FIG. 3 is a diagram for explaining a manufacturing process of the oil application roller according to the embodiment of the present invention.

FIG. 4 is an axial sectional view of an oil application roller according to a comparative example.

[Explanation of symbols]

 Reference Signs List 21 oil pan 22 first pumping roller 23 second pumping roller 24, 100 oil application roller 24a, 100a core metal 24b, 100b silicone rubber layer 31 oil regulating blade 41 fixing roller

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme court ゛ (Reference) B29K 83:00 B29K 83:00 (72) Inventor Masaaki Takahashi 3-30-2 Shimomaruko 3-chome, Ota-ku, Tokyo Inside Non-corporation (72) Osamu May, the inventor 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Yuji Kitano 3-2-2, Shimomaruko, Ota-ku, Tokyo Canon Inc. F term (reference) 2H033 AA09 BA42 BA43 3J103 AA06 AA81 BA24 GA02 GA57 GA58 HA03 HA47 4F040 AA05 AB08 AC01 BA12 CB01 CB03 CB05 4F213 AA33 AA45 AD03 AG03 AH04 WA02 WA53 WA57 WA87 WB01

Claims (7)

[Claims] 1. An oil applying apparatus for applying a release oil to an outer peripheral surface of a fixing roller for fixing a toner image to a recording material, wherein an outer diameter is continuous from a central portion to both ends along a longitudinal direction. An oil retaining layer having a crown-shaped outer peripheral surface that gradually decreases, an oil applying roller pressed against the fixing roller to apply the releasing oil to the fixing roller, and a longitudinal length of the oil applying roller. An oil applicator, comprising: an oil regulating blade that contacts the oil applying roller along a direction. 2. The oil applying roller according to claim 1, wherein the oil retaining layer is provided on an outer peripheral surface of an inverted crown-shaped core metal whose outer diameter continuously increases from a central portion to both ends along a longitudinal direction thereof. The oil application device according to claim 1, wherein 3. The oil coating device according to claim 1, wherein the oil holding layer is made of silicone rubber, and the release oil is silicone oil. 4. An inverted crown-shaped core metal whose outer diameter continuously increases from a central portion to both ends along a longitudinal direction, and a longitudinally extending core provided on an outer peripheral surface of the core metal. An oil holding layer having a crown-shaped outer peripheral surface whose outer diameter continuously decreases from a central portion toward both ends. 5. The oil application roller according to claim 4, wherein said oil holding layer is made of silicone rubber. 6. A method of manufacturing an oil application roller having an oil retaining layer formed in a crown shape whose outer diameter continuously decreases from a central portion to both ends along a longitudinal direction, the method comprising: The oil retaining layer is formed on the outer peripheral surface of an inverted crown-shaped core metal whose outer diameter continuously increases from the center portion toward both end portions along the outer peripheral surface so that the outer peripheral surface has a right cylindrical shape, A step of configuring an oil application roller intermediate body in which the thickness of the holding layer continuously decreases from the center to both ends along the longitudinal direction, and immersing the oil application roller intermediate in swelling oil, And d. Impregnating the oil retaining layer with the swelling oil. 7. The method according to claim 6, wherein the oil holding layer is made of silicone rubber, and the swelling oil is silicone oil.