JP2005016687A - Elastic roll, fixing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly efficient elastic roll which is excellent in toner mold-releasing characteristics, which can be suppressed at manufacturing costs, and in which toner can be fixed by high quality. <P>SOLUTION: The elastic roll is manufactured by a coating method. A fluororesin containing at least one of a copolymer of tetrafluoroethylene and perfluromethyl ether, and a copolymer of tetrafluoroethylene and perfluoroethyl vinyl ether, is used as a fluororesin forming a fluororesin layer at the surface of the elastic roll. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an elastic roll having a core, an elastic layer, and a fluororesin layer in that order, and a fixing device including such an elastic roll.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in image forming apparatuses such as copying machines, printers, and facsimiles, unfixed toner placed on a recording sheet is melted by heating, and the molten toner is pressed against the recording sheet to be fixed. An image is formed on the screen.
[0003]
In such an image forming apparatus, usually, a heating unit for melting the toner and a pressure unit for pressing the melted toner onto the recording sheet are provided, and at least of the heating unit and the pressure unit. On the other hand, elastic rolls are often used. Elastic rolls used for such purposes require good transportability, low permanent deformation, high elasticity, wear resistance, and good toner release properties under severe conditions of high temperature and high pressure. The As a result, as an elastic roll used for such an application, an elastic layer made of high heat-resistant rubber such as silicone rubber or fluororubber is provided on the peripheral surface of the core body. An elastic roll having a structure in which a release layer composed of fluororubber or fluororesin having toner releasability is provided on the surface is used. In recent years, so-called oil-less toners that do not require toner-releasing assistance by adding wax to the toner have been widely used, and this oil-less toner is used as a material for the release layer of the elastic roll. A fluororesin having toner releasability suitable for toner is applied. As this fluororesin, a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether, particularly a copolymer of tetrafluoroethylene and perfluoropropyl vinyl ether (particularly a copolymer of tetrafluoroethylene and perfluoropropyl vinyl ether ( Hereinafter, the abbreviation PFA) is mainly used.
[0004]
By the way, as a manufacturing method for manufacturing an elastic roll, two methods are known when roughly classified by a method of forming a release layer.
[0005]
In the first method, an elastic roll is formed by covering a surface of a roll provided with an elastic layer on a core body with a fluororesin tube (release layer) in which a fluororesin such as PFA is formed in a tube shape in advance. This is a so-called tube coating method. In recent years, a copolymer of tetrafluoroethylene and perfluoromethyl vinyl ether (hereinafter abbreviated as MFA), a copolymer of tetrafluoroethylene and perfluoroethyl vinyl ether (hereinafter referred to as EFA), which is more flexible than PFA. (Refer to Patent Document 1), and by applying these MFA and EFA as the material of the fluororesin tube, the workability when molding the fluororesin tube was improved. A molding method has been proposed (see Patent Document 2).
[0006]
Further, the second method is to apply a fluororesin (release layer) such as PFA on the surface of a roll in which an elastic layer is previously provided on the core, and further, by firing and melting the fluororesin, This is a so-called coating method in which a fluororesin is coated. Unlike the above-described tube coating method, this coating method has the advantage that the manufacturing cost can be reduced because it is not necessary to purchase an expensive tube manufactured by a specialized manufacturer from the outside.
[0007]
[Patent Document 1]
JP 2002-20434 A
[Patent Document 2]
JP-A-9-11362
[0008]
[Problems to be solved by the invention]
By the way, in the above-mentioned coating method, although baking is performed, granular PFA is inevitably left unmelted and fine unevenness is generated on the surface of the release layer. When an elastic roll having irregularities on the surface of the release layer is used as an elastic roll on the fixing side of the above-described image forming apparatus, for example, the release layer does not come into contact with the toner with a uniform pressure. There is a problem that an image defect in which particle-like spots are generated and a variation in gloss (gloss) occur in an image formed by being fixed thereon. However, on the other hand, due to the unevenness of the surface, there is an advantage that the adhesion between the release layer and the toner becomes weak, and the release property of the toner is improved.
[0009]
On the other hand, since the release layer of the elastic roll manufactured by the tube method described above is mirror-finished, defects such as image defects and gloss variations are less likely to occur. However, since the adhesion between the release layer having a mirror surface and the toner is strong, the release property of the toner is inferior to that of an elastic roll manufactured by a coating method, and as described above, an expensive tube manufactured by a specialized manufacturer. There is a problem that the manufacturing cost is high.
[0010]
In view of the above circumstances, the present invention provides a high-performance elastic roll that is excellent in toner releasability, can be manufactured at a low cost, and can fix toner with high image quality when applied to an image forming apparatus, etc. An object of the present invention is to provide a fixing device provided with such an elastic roll.
[0011]
[Means for Solving the Problems]
The first elastic roll of the present invention that achieves the above object is
A cylindrical core,
An elastic layer made of a tubular elastic body covering the peripheral surface of the core body;
The surface of the elastic layer is coated with a particulate fluororesin containing at least one of a copolymer of tetrafluoroethylene and perfluoromethyl vinyl ether and a copolymer of tetrafluoroethylene and perfluoroethyl vinyl ether. A fluororesin layer is provided.
[0012]
An elastic roll manufactured by a so-called coating method, which coats the surface of the elastic layer with particulate fluororesin, melts the fluororesin by firing, etc., but the particles remain undissolved and the surface of the fluororesin layer is subtly Have irregularities. Accordingly, when an image is output by an image forming apparatus having a conventional elastic roll coated with fluororesin particles such as PFA (a copolymer of tetrafluoroethylene and perfluoropropyl vinyl ether), the fluororesin layer and the fluororesin layer If the unfixed toner placed on the sheet does not come into uniform contact with the recording sheet and the unfixed toner is pressed against the recording sheet, the force is not uniformly applied, and there is a possibility that a defect such as an image defect may occur.
[0013]
The elastic roll of the present invention is manufactured by a coating method similar to the conventional one, but as a material of the fluororesin layer, MFA (a copolymer of tetrafluoroethylene and perfluoromethyl vinyl ether), and EFA ( And a fluororesin containing at least one of tetrafluoroethylene and perfluoroethyl vinyl ether). The MFA and EFA are superior in flexibility as compared with PFA and the like widely used as a material constituting the fluororesin layer. When the elastic roll of the present invention is applied to an image forming apparatus, the unevenness is crushed when the unfixed toner is pressed against the recording sheet even if the fluororesin layer having the unevenness and the unfixed toner are not in uniform contact. Therefore, problems such as image defects can be solved, and a high-quality image can be formed. In addition, the elastic roll manufactured by such a coating method has excellent toner releasability because the adhesion between the fluororesin layer and the toner is weak, and furthermore, an expensive tube manufactured by a specialized manufacturer is purchased from the outside. Since there is no need, the manufacturing cost can be reduced.
[0014]
Moreover, in the elastic roll of the present invention, the above-mentioned fluororesin layer has a surface with a swell of WCA of 0.6 μm or less, or a surface roughness of Ra of 0.1 μm or more and 0.4 μm or less. Is preferred.
[0015]
Usually, the surface of a fluororesin layer of an elastic roll formed by a coating method has waviness and surface roughness. As described above, even if MFA or EFA is used, if the fluororesin layer has a waviness of WCA greater than 0.6 μm or a surface roughness of Ra greater than 0.4 μm, unfixed toner When the film is pressed against the recording sheet, the unevenness of the fluororesin layer cannot be crushed, resulting in problems such as image defects. On the contrary, when the fluororesin layer has a surface roughness Ra of less than 0.1 μm, the surface is smooth like the elastic roll made by the conventional tube method. The releasability of is reduced. Therefore, by forming a fluororesin layer having a surface roughness of WCA of 0.6 μm or less or Ra of 0.1 μm or more and 0.4 μm or less, the releasability of toner and the image quality of the output image are improved. Can be made.
[0016]
Further, in the elastic roll of the present invention, the fluororesin layer includes at least one of a copolymer of tetrafluoroethylene and perfluoromethyl vinyl ether, and a copolymer of tetrafluoroethylene and perfluoroethyl vinyl ether. It is preferable that a fluororesin containing 50% or more of the total weight fraction is coated.
[0017]
If a fluororesin having a total weight fraction of MFA and EFA of less than 50% is used, sufficient flexibility cannot be obtained, and defects such as image defects cannot be resolved as in the case of using PFA. . Therefore, the total weight fraction of MFA and EFA is preferably 50% or more.
[0018]
Furthermore, the fixing device of the present invention includes the elastic roll as described above, and is used for fixing electrophotography.
[0019]
By applying such a fixing device to the image forming apparatus, the toner can be fixed with high image quality.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described.
[0021]
FIG. 1 is a cross-sectional view schematically showing a heat fixing apparatus to which an embodiment of the elastic roll of the present invention is applied.
[0022]
This heat fixing device is provided in an image forming apparatus such as a copying machine or a printer, and heats and melts unfixed toner and fixes the melted toner on a recording sheet.
[0023]
FIG. 1 shows a heat fixing device 100 and a recording sheet S on which an unfixed toner image is formed on the surface.
[0024]
The heat fixing device 100 includes a heating unit 110 that melts the unfixed toner S1 placed on the recording sheet S by heating, and a pressure unit 120 that presses the melted unfixed toner S1 onto the recording sheet S.
[0025]
The heating unit 110 includes a heat source 111 inside a cylindrical elastic roll 200. This elastic roll 200 is an embodiment of the elastic roll of the present invention. The pressure unit 120 includes a belt 121 made of an elastic resin, a pressure pad 122 that presses the belt 121 from the inside toward the heating unit 110, and a support member 123 that supports the pressure pad 122.
[0026]
The belt 121 is pressed against the elastic roll 200 of the heating unit 110 by the pressure pad 122. When the elastic roll 200 is rotated in the direction of arrow A in the drawing by a motor (not shown), the belt 121 follows the elastic roll 200. To rotate in the direction of arrow B. As a result, the recording sheet S conveyed from the upstream side of the conveyance path (not shown) passes between the elastic roll 200 and the belt 121 of the pressure unit 120 and is conveyed downstream. When the recording sheet S passes between the elastic roll 200 and the belt 121 of the pressure unit 120, the unfixed toner S1 on the recording sheet S is heated and melted by the heat source 111. At this time, the recording sheet S is pressed against the elastic roll 200 over the belt 121 by the pressure pad 122, the melted toner S <b> 1 is pressed against the recording sheet S, and the toner image is fixed on the recording sheet S.
[0027]
FIG. 2 is a cross-sectional view of the elastic roll shown in FIG.
[0028]
2A shows a cross-sectional view of the elastic roll 200, and FIG. 2B shows an enlarged view of the cross section P surrounded by a broken line in FIG.
[0029]
The elastic roll 200 has a layer structure having an elastic layer 220 and a fluororesin layer 230 in that order on the peripheral surface of a cylindrical core 210. The core body 210 corresponds to an example of a core body according to the present invention, and the elastic layer 220 corresponds to an example of an elastic layer according to the present invention. Furthermore, the fluororesin layer 230 corresponds to an example of the fluororesin layer referred to in the present invention. An adhesive 241 is interposed between the peripheral surface of the core body 210 and the elastic layer 220, and the adhesive 240 bonds the elastic layer 220 and the core body 210 to each other. An adhesive 242 interposed between the elastic layer 220 and the fluororesin layer 230 adheres the elastic layer 220 and the fluororesin layer 230 to each other.
[0030]
Here, in the elastic roll 200 shown in FIG. 1 and FIG. 2, a feature as one embodiment of the present invention is that the material constituting the fluororesin layer 230 and the fluorine resulting from the method of manufacturing the elastic roll 200 The resin layer 230 has a structure. Below, the manufacturing method of an elastic roll is demonstrated first.
[0031]
FIG. 3 is a diagram illustrating a method for producing an elastic roll.
[0032]
The elastic roll manufacturing method shown in FIG. 3 includes a core body forming process (step S10), an elastic body forming process (step S20), an insertion process (step S30), a heat bonding process (step S40), and a fluororesin layer. The formation method (step S50) and the formation method of the fluororesin layer in the fluororesin layer formation process are conventionally widely known as “coating methods”.
[0033]
The core body forming process (step S10) is a process of forming the core body 210 also shown in FIG. The core body 210 is made of aluminum, and in the core body forming process, aluminum is molded into a cylindrical shape, and the core body 210 is formed.
[0034]
The elastic body forming process (step S20) is a process of forming the elastic layer 220 also shown in FIG. In this elastic body forming process, the elastic body is formed into a tubular shape, and the elastic layer 220 is formed. The elastic body constituting the elastic layer 220 is preferably silicone rubber or fluororubber, the elastic body preferably has a rubber hardness of 50 ° (JIS-A) or less, and the elastic layer 220 has a thickness of 0.00. It is preferably formed to be 3 mm to 3.00 mm. By using silicone rubber or fluororubber, the durability of the elastic layer can be improved, and by providing the thickness as described above, a high-quality fixed image can be obtained by the effect of the elastic layer.
[0035]
Here, the core forming process (step S10) and the elastic body forming process (step S20) are individually performed, and either process may be performed first.
[0036]
Next, an insertion process (step S30) is performed.
[0037]
In the insertion process (step S30), first, a core body to which the thermosetting adhesive 241 is applied and the adhesive 241 is applied to the peripheral surface of the core body 210 created in the core body formation process (step S10). 210 is inserted into the elastic layer 220 created in the elastic body formation process (step S20). In the following description, a structure in which the core body 210 is inserted into the elastic layer 220 is referred to as a roll body.
[0038]
Next, a heat bonding process (step S40) is performed.
[0039]
In the heating and bonding process (step S40), the adhesive 241 is thermally cured by heating the roll body 201 created in the insertion process (step S30) in the circulation oven 300. As a result, the core body 210 and the tubular elastic body 220 are bonded to each other.
[0040]
Finally, a fluororesin layer forming process (step S50) for forming the fluororesin layer 230 on the peripheral surface of the roll body 201 is performed.
[0041]
In the fluororesin layer forming process (step S50), the adhesive 242 is applied to the peripheral surface of the roll body 201 by a spray coater (not shown) and air-dried, and then uniformly and particulately by a spray coater thereon. A dispersion containing a fluororesin is applied. Further, the roll body 201 coated with the dispersion is air-dried, and the roll body 201 is baked in the circulation oven 300 to melt the particulate fluororesin and form the fluororesin layer 230. In this embodiment, since the fluororesin layer 230 is formed by coating the fluororesin particles in the fluororesin layer formation process, it is not necessary to purchase an expensive tube manufactured by a specialized manufacturer from the outside. Manufacturing costs can be reduced.
[0042]
Here, the fluororesin constituting the fluororesin layer 230 includes at least one of the above-described MFA or EFA in a total weight fraction of 50% or more. By using MFA or EFA as the fluororesin, the flexibility of the fluororesin layer 230 is improved. This fluororesin may contain PFA or the like in addition to MFA or EFA.
[0043]
Moreover, it is preferable that this fluororesin layer 230 is formed so that the thickness may be 10 micrometers-40 micrometers. By forming the fluororesin layer in this way, it is possible to achieve both performance and durability as an elastic roll.
[0044]
FIG. 4 is a view showing a fluororesin layer formed in the fluororesin layer forming process shown in FIG.
[0045]
Waviness 231 and unevenness 232 are generated on the surface of the fluororesin layer 230 formed by the coating method as shown in FIG. Usually, the dispersion used in the fluororesin layer forming process of FIG. 3 contains fluororesin particles of different sizes in order to prevent cracking when applied to the roll body 201. Due to the difference in the size of the fluororesin particles, waviness 231 as shown in FIG. 4 occurs. Further, in the process of forming the fluororesin layer in FIG. 3, although the fluororesin particles are baked and melted, the remaining fluororesin particles cause unevenness 232 on the surface of the fluororesin layer 230.
[0046]
Here, the swell 231 has a WCA of 0.6 μm or less, and the surface roughness of the fluororesin layer 230 formed by the unevenness 232 is formed such that Ra is 0.1 μm or more and 0.4 μm or less. Since the fluororesin layer 230 has appropriate waviness and surface roughness on the surface, the releasability of the toner can be improved. Further, the fluororesin layer 230 is made of MFA or EFA having excellent flexibility. If the waviness or surface roughness is about the above, they are crushed when the toner is pressed against the recording sheet. Can be suppressed. Therefore, by adopting such an elastic roll 200 as the heating unit 110 of the heat fixing apparatus 100 shown in FIG. 1, the unfixed toner image S1 can be fixed on the recording sheet S with high image quality.
[0047]
Above, description of one Embodiment of the elastic roll of this invention and the heat fixing apparatus using the elastic roll is complete | finished.
[0048]
Here, although the elastic roll created by the conventional coating method has been described above, the elastic roll in the present invention only needs to have a fluororesin layer formed by coating a fluororesin on the surface, About the manufacturing method of a core and an elastic layer, it is not restricted to the above methods.
[0049]
【Example】
Examples of the present invention will be described below.
[0050]
First, as an example of the present invention, the material, the material distribution ratio, the forming method, the surface roughness, and the waviness of the fluororesin layer 230 of the elastic roll 200 were changed within the ranges specified in the present invention. Examples will be given.
[0051]
Next, as a comparative example for the above-described embodiment, five types in which any one of the above-described materials, material distribution ratio, forming method, surface roughness, and swell are excluded from the ranges defined in the present invention. The comparative example is given.
[0052]
FIG. 5 is a table showing the above-described examples and comparative examples, and evaluation results for them.
[0053]
The table shown in FIG. 5 shows the results of Example 1 to Example 5, Comparative Example 1 to Comparative Example 5, and further.
[0054]
Here, in Comparative Examples other than Examples 1 to 5 and Comparative Example 4 to which the coating method shown in FIG. 3 is applied, the hardness after curing is 35 ° (on the peripheral surface of the aluminum core body). A roll body made of an addition-reaction type silicone rubber (JIS-A) and having an elastic layer with a diameter of φ20 and a thickness of 0.75 mm is commonly used, and a thickness of 25 μm is formed on the surface of such a roll body. The fluororesin layer is coated so as to be ˜30 μm.
[0055]
Moreover, in the comparative example 4 to which the tube method is applied, according to other examples and comparative examples to which the coating method is applied, between the aluminum core and the fluororesin tube having a thickness of 30 μm. An elastic layer having a diameter of φ20 and a thickness of 0.75 mm is formed from an addition reaction type silicone rubber having a hardness after curing of 35 ° (JIS-A).
[0056]
(Example 1)
In Example 1, according to the coating method shown in FIG. 3, using a fluororesin containing 50% by weight of EFA and PFA, the surface roughness is Ra of 0.1 μm, and the undulation is WCA of 0.5 μm. It is an elastic roll which has the fluororesin layer formed in this way.
[0057]
Here, the formation method of the fluororesin layer referred to as “coating a granular fluororesin” in the present invention represents a so-called coating method applied to this embodiment.
[0058]
In addition, the fluororesin containing 50% by weight of EFA and PFA is a numerical value regulation according to the present invention that “at least one of MFA or EFA contains 50% or more in total weight fraction”. This is a fluororesin filled with EFA.
[0059]
Moreover, said surface roughness (Ra 0.1 micrometer) is the surface roughness which satisfies the numerical value minimum limit of 0.1 micrometer or more and 0.4 micrometer or less with Ra said to this invention.
[0060]
Furthermore, the swell (0.5 μm in WCA) is a swell that satisfies the numerical definition of 0.6 μm or less in WCA according to the present invention.
[0061]
(Example 2)
In Example 2, the surface roughness was 0.4 μm in Ra and the waviness was 0.6 μm in WCA using a fluororesin containing 50% by weight of MFA and PFA according to the coating method as in Example 1. It is an elastic roll which has a fluororesin layer formed to become.
[0062]
The fluororesin containing 50% by weight of the above MFA and PFA has a numerical value limit of “containing at least one of MFA or EFA in a total weight fraction of 50% or more” according to the present invention. , A fluororesin filled with MFA.
[0063]
The surface roughness (Ra: 0.4 μm) is the surface roughness that satisfies the numerical upper limit of 0.1 to 0.4 μm in terms of Ra according to the present invention.
[0064]
Further, the swell (0.6 μm in WCA) is a swell that satisfies the numerical value limit of 0.6 μm or less in WCA according to the present invention.
[0065]
Example 3
Example 3 is similar to Examples 1 to 2 in accordance with the coating method, using a fluororesin containing 25% by weight of EFA, 25% by weight of MFA, and 50% by weight of PFA. This is an elastic roll having a fluororesin layer 230 formed such that the thickness is 0.3 μm Ra and the swell is 0.5 μm WCA.
[0066]
In addition, the fluororesin contained in the blend of 25% by weight of EFA, 25% by weight of MFA, and 50% by weight of PFA is referred to in the present invention as “total weight of at least one of MFA and EFA. It is a fluororesin that satisfies the numerical limit of “contains 50% or more by fraction” using EFA and MFA.
[0067]
Further, the surface roughness (Ra: 0.3 μm) is a surface roughness that satisfies the numerical specification of Ra of 0.1 μm or more and 0.4 μm or less according to the present invention.
[0068]
Furthermore, the swell (0.5 μm in WCA) is a swell that satisfies the numerical definition of 0.6 μm or less in WCA according to the present invention.
[0069]
(Example 4)
In Example 4, according to the coating method in the same manner as in Examples 1 to 3, a fluororesin containing 60% by weight of EFA and 40% by weight of PFA was used. This is an elastic roll having a fluororesin layer 230 formed to have a thickness of 3 μm and a waviness of 0.5 μm by WCA.
[0070]
Further, the fluororesin containing 60% by weight of EFA and 40% by weight of PFA is referred to in the present invention as “at least one of MFA and EFA is 50% or more in total weight fraction. It is a fluororesin that satisfies the numerical definition “includes” using FEA.
[0071]
Further, the surface roughness (Ra: 0.3 μm) is a surface roughness that satisfies the numerical specification of Ra of 0.1 μm or more and 0.4 μm or less according to the present invention.
[0072]
Furthermore, the swell (0.5 μm in WCA) is a swell that satisfies the numerical definition of 0.6 μm or less in WCA according to the present invention.
[0073]
(Example 5)
Example 5 is similar to Examples 1 to 4 in accordance with the coating method, using a fluororesin containing 20 wt% EFA, 40 wt% MFA, and 40 wt% PFA. This is an elastic roll having a fluororesin layer 230 formed such that the thickness is 0.3 μm Ra and the swell is 0.5 μm WCA.
[0074]
In addition, the fluororesin containing 20% by weight of EFA, 40% by weight of MFA, and 40% by weight of PFA is referred to in the present invention as “total weight of at least one of MFA or EFA. It is a fluororesin that satisfies the numerical definition of “contains 50% or more by fraction” using EFA and MFA.
[0075]
Further, the surface roughness (Ra: 0.3 μm) is a surface roughness that satisfies the numerical specification of Ra of 0.1 μm or more and 0.4 μm or less according to the present invention.
[0076]
Furthermore, the swell (0.5 μm in WCA) is a swell that satisfies the numerical definition of 0.6 μm or less in WCA according to the present invention.
[0077]
(Comparative Example 1)
In Comparative Example 1, the surface roughness was set to Ra of 0. 0 by using a fluororesin containing 40 wt% EFA and 60 wt% PFA according to the coating method in the same manner as in Examples 1 to 5. This is an elastic roll having a fluororesin layer 230 formed to have a thickness of 3 μm and a waviness of 0.5 μm by WCA.
[0078]
The blending amount of EFA in Comparative Example 1 is the blending amount deviated downward relative to the numerical specification “containing at least one of MFA or EFA in a total weight fraction of 50% or more” according to the present invention. It is.
[0079]
(Comparative Example 2)
Comparative Example 2 is formed using a fluororesin containing 50% by weight of EFA and PFA in accordance with a tube method, not a coating method. As a result, the surface roughness is 0.04 μm in Ra and the waviness is WCA. This is an elastic roll having a fluororesin layer 230 of 0.1 μm.
[0080]
The elastic roll of Comparative Example 2 is manufactured by a tube method, which does not satisfy the fluororesin layer forming method of “coating granular fluororesin”. Furthermore, since the fluororesin layer formed by the tube method is a mirror surface, the surface roughness Ra is 0.04 μm, which is a numerical value regulation in the present invention that Ra is 0.1 μm or more and 0.4 μm or less. The surface roughness is shifted downward.
[0081]
(Comparative Example 3)
Comparative Example 3 follows the same coating as in Examples 1 to 5, and uses a fluororesin containing 50% by weight of EFA and PFA. The surface roughness is 0.5 μm in Ra and the waviness is WCA. It is an elastic roll having a fluororesin layer 230 formed to have a thickness of 0.6 μm.
[0082]
The surface roughness (Ra 0.5 μm) in Comparative Example 3 is a surface roughness that deviates upward relative to the numerical value regulation of Ra 0.1 μm or more and 0.4 μm or less, as referred to in the present invention.
[0083]
(Comparative Example 4)
In Comparative Example 4, the surface roughness was set to Ra after a fluororesin layer was formed using a fluororesin containing 50% by weight of EFA and PFA according to the coating method as in Examples 1 to 5. Is an elastic roll having a fluororesin layer polished so that the waviness is 0.05 μm and the waviness is 0.5 μm.
[0084]
The surface roughness (Ra: 0.05 μm) in Comparative Example 3 is a surface roughness that is shifted downward relative to the numerical value regulation of Ra of 0.1 μm or more and 0.4 μm or less, as referred to in the present invention.
[0085]
(Comparative Example 5)
In Comparative Example 5, the surface roughness was 0.4 μm in Ra and the waviness was WCA using a fluororesin containing 50% by weight of MFA and PFA according to the coating method in the same manner as in Examples 1 to 5. It is an elastic roll which has the fluororesin layer 230 formed so that it may become 0.7 micrometer.
[0086]
The waviness (0.7 μm in WCA) in the comparative example 3 is a waviness that is shifted upward with respect to the numerical value specification of 0.6 μm or less in WCA according to the present invention.
[0087]
Next, evaluation results for these examples and comparative examples will be described.
[0088]
(Evaluation results)
Here, the elastic rolls of the above-described examples and comparative examples are respectively manufactured, each elastic roll is mounted on a commercially available laser printer, a solid image is output under the same fixing conditions, the image quality test of the image, and the toner And fixing tests were conducted.
[0089]
First, the evaluation results for the elastic rolls of Examples 1 to 5 will be described. In the above-described image quality test for the elastic rolls of these examples, it was evaluated that the image quality and the image quality of the output images were good with no variation in the image defect or gloss in the output images. . Further, in the toner fixing test, for all elastic rolls, even when the fixing temperature in the fluororesin layer is 210 ° C. or higher, the toner is peeled off from the fluororesin layer and has good toner releasability. It was evaluated.
[0090]
Next, evaluation results for the elastic rolls of Comparative Examples 1 to 5 will be described.
[0091]
First, the evaluation results for the image quality test will be described.
[0092]
In this image quality test, it was the elastic rolls of Comparative Example 2 and Comparative Example 4 that gave the same good evaluation results as in the above Examples. With respect to the elastic rolls of Comparative Example 1, Comparative Example 3, and Comparative Example 5, all of the output images had an image defect, and it was evaluated that the image quality was poor.
[0093]
In Comparative Example 1, it can be seen that the “material mixing ratio of EFA and MFA” of the fluororesin constituting the fluororesin layer is shifted downward, and the flexibility of the fluororesin is insufficient. In Example 1 (EFA is 50% by weight), good evaluation has been obtained, and from this, the “MFA and EFA material blending ratio” should be 50% or more by weight. It was confirmed that.
[0094]
Moreover, the comparative example 3 has surface roughness shifted | deviated above numerical value prescription | regulation, and it turns out that the surface of a fluororesin layer is too rough. In Example 2 (surface roughness Ra of 0.4 μm), good evaluation has been obtained, and from this, a numerical value regulation of Ra of 0.4 μm or less in “surface roughness” is appropriate. Was confirmed.
[0095]
Further, in Comparative Example 5, the undulation is shifted upward from the numerical value specification, and it can be seen that the undulation of the surface of the fluororesin layer is too large. In Example 2 (swell is 0.6 μm in WCA), good evaluation has been obtained, and from this, it has been confirmed that the numerical regulation of “swell” in WCA of 0.6 μm or less is appropriate. It was.
[0096]
Next, evaluation results for the toner fixing test will be described.
[0097]
It was the elastic rolls of Comparative Example 1, Comparative Example 3, and Comparative Example 5 that obtained the same good evaluation results as in the above examples in this image quality test. As for the elastic rolls of Comparative Example 2 and Comparative Example 4, when the fixing temperature in the fluororesin layer is 200 ° C., the toner wraps around the elastic roll without being peeled off from the fluororesin layer, and the toner release property Was rated as bad.
[0098]
The comparative example 2 is manufactured by the tube method, and does not satisfy the formation rule of the fluororesin layer. In Examples 1 to 5 to which the coating method was applied, good evaluation was obtained. From this, it was confirmed that the coating method was appropriate as a method for forming the fluororesin layer.
[0099]
Moreover, although the comparative example 4 is manufactured by the coating method, the surface is grind | polished and the surface roughness has shifted | deviated below numerical value regulation, and it turns out that the surface of a fluororesin layer is smooth. In Example 1 (surface roughness Ra of 0.1 μm), good evaluation has been obtained, and from this, a numerical value regulation of “surface roughness” Ra of 0.1 μm or more is appropriate. Was confirmed.
[0100]
【The invention's effect】
As described above, according to the elastic roll and the fixing device of the present invention, it is possible to reduce the manufacturing cost while maintaining the toner releasability, and fix the toner with high image quality when applied to an image forming apparatus or the like. can do.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view schematically showing a heat fixing apparatus to which an embodiment of an elastic roll of the present invention is applied.
FIG. 2 is a cross-sectional view of the elastic roll shown in FIG.
FIG. 3 is a diagram showing an example of the production method of the present invention.
4 is a view schematically showing extrusion molding in the elastic body forming process shown in FIG. 4. FIG.
FIG. 5 is a table showing comparative examples together with examples.
[Explanation of symbols]
100 Heat fixing device
110 Heating part
111 heat source
120 Pressure unit
121 belt
122 Pressure pad
123 Support member
210 core
220 Elastic layer
230 Fluororesin layer
231 Swell
232 irregularities
241 Adhesive
242 Adhesive

Claims (5)

A cylindrical core,
An elastic layer made of a tubular elastic body covering the peripheral surface of the core;
A fluororesin in which the surface of the elastic layer is coated with a fluororesin containing at least one of a copolymer of tetrafluoroethylene and perfluoromethyl vinyl ether and a copolymer of tetrafluoroethylene and perfluoroethyl vinyl ether. An elastic roll characterized by comprising a layer. The elastic roll according to claim 1, wherein the fluororesin layer has undulations having a WCA of 0.6 μm or less on the surface. The elastic roll according to claim 1, wherein the fluororesin layer has a surface roughness Ra of 0.1 μm to 0.4 μm. The fluororesin layer contains at least one of a copolymer of tetrafluoroethylene and perfluoromethyl vinyl ether and a copolymer of tetrafluoroethylene and perfluoroethyl vinyl ether in a total weight fraction of 50% or more. The elastic roll according to claim 1, wherein the elastic roll is coated with a fluororesin. A fixing device used for fixing an electrophotography, comprising the elastic roll according to claim 1.

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