JP5469858B2 - Roll cover - Google Patents

Description

  The present invention relates to a roll cover that constitutes a part of a roll used as, for example, a heat fixing roll or a pressure roll in a copying machine or a printer.

  A copying machine, a printer, and the like are provided with a heat roll type fixing device that heats and fixes toner, and the fixing device includes a heat fixing roll and a pressure roll that is pressed against the heat fixing roll (hereinafter, referred to as “heat fixing roll”). (Referred to as “roll”). Such a roll is composed of a cylindrical roll body and a tubular roll cover covering the outer peripheral surface thereof. In the roll cover, the inner peripheral surface of the roll cover is bonded to the outer peripheral surface of the roll body so that the roll cover does not deviate from the roll body due to frictional resistance when the roll rotates.

  As the material of such a roll cover, a fluororesin is optimal because heat resistance that does not deteriorate due to heating during heat fixing and non-adhesiveness that the outer peripheral surface of the roll cover does not adhere to a recording medium such as paper are required. . However, since the fluororesin has non-adhesive properties, the inner peripheral surface of the roll cover cannot be adhered to the outer peripheral surface of the roll body as it is. Therefore, it is necessary to surface-treat the inner peripheral surface of the roll cover once to exhibit adhesiveness, and then apply a primer to the inner peripheral surface of the roll cover to adhere to the outer peripheral surface of the roll body.

As the surface treatment of the inner peripheral surface of the roll cover made of this fluororesin, a solution in which a complex of metallic sodium and naphthalene is dissolved in an organic solvent or a liquid ammonia solution in which metallic sodium is dissolved in liquid ammonia are used. There is a method in which the inside of the roll cover is washed with alcohol, water, and acetone after being sealed and chemically treated (see Patent Document 1).
Japanese Patent Laid-Open No. 10-60139

  In the above-described surface treatment of the inner peripheral surface of the roll cover made of the conventional fluororesin, it is necessary to pay attention to the handling of a waste solution such as a solution containing metal sodium or an alcohol containing metal sodium. In addition, since surface treatment using a liquid ammonia solution needs to be performed at a low temperature, a large facility is required. Therefore, the roll cover tends to be expensive. As other surface treatments of the inner peripheral surface of the roll cover made of a fluororesin, there are plasma radiation treatment and corona discharge treatment, but it is difficult to sufficiently exhibit adhesiveness by these surface treatments.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a low-cost roll cover that has high adhesion to a roll body.

In order to achieve the above object, the roll cover of the present invention is formed of a thermoplastic fluororesin, and is formed of a thermoplastic fluororesin that does not include an adhesive functional group in a tubular roll cover covering a cylindrical roll body. A first layer and a second layer formed on the inner peripheral surface of the first layer by a thermoplastic fluororesin containing a hydroxyl group or an acid anhydride group which is an adhesive functional group activated by ultraviolet irradiation And at least the inner peripheral surface of the second layer is treated with ultraviolet rays irradiated from the outside of the first layer.

According to this, the hydroxyl group or acid anhydride group, which is an adhesive functional group activated by ultraviolet irradiation contained in the second layer of the roll cover made of thermoplastic fluororesin, can be activated by ultraviolet irradiation. Therefore, it can be set as the roll cover which has a 2nd layer with high adhesiveness with a roll main body. Particularly, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer containing hydroxyl group or acid anhydride group as a thermoplastic fluororesin containing ultraviolet light irradiated by a low-pressure mercury lamp and an adhesive functional group activated by ultraviolet irradiation. It has been confirmed by the present inventor that the adhesiveness to the roll body is greatly improved by using a combination with coalescence (modified PFA). Moreover, since the surface treatment of the inner peripheral surface of the second layer can be performed only by the ultraviolet irradiation treatment, a low-cost roll cover can be obtained by reducing the number of work steps and simplifying the equipment. And since it is only necessary to irradiate ultraviolet rays from the outside of the first layer that forms the outer layer of the roll cover, it is possible to carry out consistently and continuously from the forming process to the surface treatment of the roll cover. Cost can be reduced.

  Embodiments according to the present invention will be described below. Note that the embodiments described below do not limit the invention according to the claims, and all combinations of features described in the embodiments are not necessarily essential to the solution means of the invention. Absent.

  1A and 1B are a perspective view and a sectional view taken along line XX showing a part of a roll having a roll cover according to an embodiment of the present invention. The roll 100 is substantially composed of a core metal 10, a roll body 20, and a roll cover 40. The cored bar 10 is formed in a hollow cylindrical shape or a solid cylindrical shape from a metal material such as aluminum. The roll body 20 is formed in a hollow cylindrical shape by an elastic material such as silicon rubber, silicon foam, urethane rubber, or fluororubber, and the cored bar 10 is inserted into the inner periphery of the roll body 20, and the inner periphery of the roll body 20. The surface and the outer peripheral surface of the cored bar 10 are bonded.

  The roll cover 40 is formed in a tubular shape that can cover the outer peripheral surface of the roll body 20 with a thermoplastic fluororesin, and a first layer 41 that constitutes an outer layer of the roll cover 40 and a first layer that constitutes an inner layer of the roll cover 40. 2 layers 42. The first layer 41 is formed of a thermoplastic fluororesin that does not include a hydroxyl group that is an adhesive functional group, and the second layer 42 is formed of a thermoplastic fluororesin that includes a hydroxyl group. Since the first layer 41 does not contain a hydroxyl group, it exhibits non-tackiness that does not stick to a recording medium such as paper, and the second layer 42 exhibits a bonding property that adheres to the roll body 20 because it contains a hydroxyl group. It is supposed to be. A thermoplastic fluororesin containing an acid anhydride group instead of a hydroxyl group may be used.

  Examples of the thermoplastic fluororesin containing no hydroxyl group or acid anhydride group applicable to the first layer 41 constituting the outer layer of the roll cover 40 include tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), ethylene -Tetrafluoroethylene copolymer (ETFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF) or the like alone or in combination Select and use.

  If the durability of the roll cover 40 is pursued, it is preferable that the melt flow rate (hereinafter referred to as “MFR”) measured by the method defined in American Standard Testing Material (ASTM) D3307 is 10 or less. Moreover, in order to maintain sufficient productivity by the extrusion process of the roll cover 40, it is preferable that MFR is 0.2 or more. Therefore, PFA or ETFE is preferable for the first layer 41, but PFA is most preferable in view of non-adhesiveness and heat resistance.

  Examples of the thermoplastic fluororesin containing a hydroxyl group or an acid anhydride group applicable to the second layer 42 constituting the inner layer of the roll cover 40 include a monomer (monomer) containing a hydroxyl group or an acid anhydride group, and a hydroxyl group. It can be obtained by copolymerization with a monomer (monomer) that does not contain a group or an acid anhydride group. Examples of the monomer containing a hydroxyl group or an acid anhydride group are shown below, but the monomer containing a hydroxyl group or an acid anhydride group is not limited to these, and other applicable hydroxyl groups or A monomer containing an acid anhydride group may be used.

Examples of monomers containing hydroxyl groups or acid anhydride groups CF ₂ = CF—R—CH ₂ —OH,
_{CH 3 = CH-R-CH} 2 -OH,
_{CF 2 = CH-R-CH} 2 -OH,
_{CF 2 = CF-O-R} -CH 2 -OH,
_{CH 2 = CH-O-R} -CH 2 -OH,
CF ₂ = CFCF ₂ —O—R—CH ₂ —OH,
_{CH 2 = CFCF 2 -R-CH} 2 -OH,
CH ₂ = CFCF ₂ —O—R—CH ₂ —OH,
R is
a:-(CX ₂ ) _l- ,
_{b :-( OCF (CF 3) CF} 2) m -,
_{c :-( OCF 2 CF (CF 3} )) m -,
_{d :-( OCF (CF 3))} n -,
_{e :-( OCF 2 CF 2) n} -,
Any one or a combination of two or more selected from the above.
X is H (hydrogen) or F (fluorine);
1: 0-40, m: 0-10, n: 0-10.
Or

Etc.

  Examples of monomers that do not contain hydroxyl or acid anhydride groups include one of ethylene, propylene, tetrafluoroethylene, hexafluoropropylene, perfluoroalkyl vinyl ether, chlorotrifluoroethylene, vinylidene fluoride, and the like. These can be selected and used, or a combination of two or more of these can be selected and used. The modified PFA is most suitable for the second layer 42 from the viewpoint of adhesion and heat resistance.

  By using the roll cover 40 having such a two-layer structure, the first layer 41 and the second layer 42 are welded together because they are thermoplastic fluororesins, and the second layer 42 and the roll body 20 are The inner peripheral surface of the second layer 42 is bonded to the outer peripheral surface of the roll body 20 without performing a conventional surface treatment. As a result, the core metal 10, the roll body 20, and the roll cover 40 are combined, and the roll cover 40 rotates together with the core metal 10 and the roll body 20 by rotating the core metal 10 in the axial direction.

  However, it has been required to further improve the adhesiveness of the roll cover 40 to the roll main body 20, and the present inventor repeatedly creates a two-layered roll cover 40 as described above, repeatedly performs various experiments, and studies repeatedly. As a result, the thermoplastic fluororesin containing a specific hydroxyl group or acid anhydride group, that is, a modified PFA, greatly improves the adhesiveness when irradiated with specific ultraviolet light, that is, ultraviolet light emitted from a low-pressure mercury lamp. I found.

  The roll cover 40 has a first layer 41 made of PFA and a second layer 42 made of modified PFA, and a low-pressure mercury lamp from the outside of the first layer 41 to the second layer 42. Is irradiated with ultraviolet rays. This low-pressure mercury lamp irradiates ultraviolet rays having wavelengths of 185 nm and 254 nm. It has been confirmed that this ultraviolet ray has no influence on the base material when it passes through the PFA which is the base material of the first layer 41 and the second layer 42. By irradiating from the outside of the first layer 41, the adhesiveness of the second layer 42 can be greatly improved.

  Further, the diameter of the roll cover 40 can be arbitrarily adjusted according to the size of the roll body 20. The thickness of the roll cover 40 can be arbitrarily selected depending on the type of the roll 100 and its usage, but is generally 10 μm to 300 μm, more preferably 20 μm to 150 μm. In particular, from the viewpoint of durability and wear resistance, the thickness of the first layer 41 is preferably at least one third of the thickness of the roll cover 40, and the thickness of the second layer 42 is In order to ensure sufficient adhesive strength with the roll body 20, the thickness is preferably 0.1 μm or more.

  Next, a method for manufacturing the roll cover 40 will be described. The roll cover 40 can be manufactured by an ultraviolet irradiation device equipped with a normal extruder and a low-pressure mercury lamp. For example, PFA that is the material of the first layer 41 and modified PFA that is the material of the second layer 42 are extruded from each extruder into a two-layer mold and distributed into two layers in the two-layer mold. . The object to be molded distributed in two layers is shaped into a desired dimensional shape using a sizing die or the like. As a method for shaping into a desired dimensional shape, a method such as a vacuum sizing method or an inside mandrel method can also be used.

  Subsequently, the molded body shaped into a desired size and shape is drawn into the ultraviolet irradiation device, and ultraviolet rays are irradiated from the low-pressure mercury lamp toward the molded body. At this time, the ultraviolet rays pass through the first layer 41 and the second layer 42 from the outside of the first layer 41, reach the inner peripheral surface of the second layer 42, and surface-treat the inner peripheral surface. Thereby, the adhesiveness with respect to the outer peripheral surface of the roll main body 20 of the inner peripheral surface of the 2nd layer 42 can be improved significantly. Thus, since it is not necessary to irradiate ultraviolet rays from the inner side of the second layer 42, it is only necessary to irradiate from the outer side of the first layer 41, so that a normal ultraviolet irradiation device can be used. Therefore, since it can process continuously with a simple apparatus from extrusion molding of the roll cover 40 to ultraviolet irradiation, the manufacturing efficiency of the roll cover 40 can be improved and cost can be reduced. It goes without saying that ultraviolet rays may be irradiated from the inside of the second layer 42.

  Next, the adhesion test of the roll cover 40 manufactured by the above manufacturing method will be described. As the roll cover 40, PFA (Fullon P-802UP manufactured by Asahi Glass Co., Ltd.) is selected as the material of the first layer 41, and modified PFA (Neofuron RAP manufactured by Daikin Industries, Ltd.) is selected as the material of the second layer 42. Using a molding machine, a roll cover 40 having a two-layer structure (total thickness 30 μm) having an outer diameter of 29 mm, a first layer 41 thickness of 25 μm, and a second layer 42 thickness of 5 μm, an outer diameter of 29 mm, A molded body having a two-layer structure (total thickness 50 μm) in which the thickness of the first layer 41 was 45 μm and the thickness of the second layer 42 was 5 μm was prepared. Subsequently, the roll cover 40 was formed by irradiating ultraviolet rays for a predetermined time with a predetermined interval between the low-pressure mercury lamp and the outer peripheral surface of the first layer 41.

  The roll cover 40 created in this way is cut into 115 mm square, silicon rubber is applied to the surface (inner peripheral surface) of the second layer 42, and the surfaces (inner peripheral surface) of the second layer 42 are bonded together, It was left in a constant temperature bath at 140 ° C. for 1 hour. And the ratio of the area which the silicon rubber layer caused the cohesive failure with respect to the contact area with the silicon rubber when the adhesive surface was peeled off was visually judged, and was quantified as the adhesive area. As a result, in the roll cover 40 having a total thickness of 30 μm, the distance between the 110 watt (W) low-pressure mercury lamp and the outer peripheral surface of the first layer 41 is 10 mm to 20 mm, and the ultraviolet irradiation time is 2 seconds to 10 seconds. In the roll cover 40 having a total thickness of 50 μm, the distance between the 110 watt (W) low-pressure mercury lamp and the outer peripheral surface of the first layer 41 is 10 mm, and the ultraviolet irradiation time is 7%. The adhesion area of 90% or more was obtained when the time was from 1 second to 13 seconds. Thus, it was confirmed that the adhesiveness of the modified PFA of the second layer 42 of the roll cover 40 can be significantly improved by irradiating with ultraviolet rays from a low-pressure mercury lamp.

  As described above, according to the roll cover 40 of the present embodiment, the hydroxyl group or acid anhydride group contained in the second layer 42 made of modified PFA can be activated by ultraviolet irradiation with a low-pressure mercury lamp. The adhesion with the roll body 20 can be greatly improved. Moreover, since the surface treatment of the inner peripheral surface of the second layer 42 can be performed only by the ultraviolet irradiation treatment, the roll cover 40 can be made at low cost by reducing the number of work steps and simplifying the equipment. Then, since it is only necessary to irradiate ultraviolet rays from the outside of the first layer 41 that forms the outer layer of the roll cover 40, it is possible to carry out consistently and continuously from the forming process to the surface treatment of the roll cover 40. The cost can be further reduced.

  In this embodiment, the roll cover 40 has a two-layer structure including the first layer 41 and the second layer 42. However, the roll cover 40 is not limited to the two-layer structure, and at least the first layer 41 has a two-layer structure. If it is a multilayer structure having one layer and a second layer, for example, a three-layer or four-layer structure may be used. Moreover, the roll 100 has the roll main body 20 and the cored bar 10, but the roll 100 uses the cored bar 10 as the roll main body 20, and the cored bar 10 functions as the roll main body 20. It may be a simple configuration. Even if an excimer lamp that irradiates ultraviolet rays having the same wavelength as that of the low-pressure mercury lamp is used, the adhesiveness of the second layer 42 can be greatly improved.

  The roll cover according to the present invention can be applied to a roll made of a fluororesin used in various fields, in addition to being used in a heating and pressure fixing unit of a copying machine or a printer.

It is the perspective view and XX sectional view which show a part of roll which has the roll cover which concerns on embodiment of this invention.

Explanation of symbols

10 cored bar, 20 roll body, 30 adhesive layer, 40 roll cover, 41 first layer, 42 second layer

Claims (3)

In a tubular roll cover formed of a thermoplastic fluororesin and covering a cylindrical roll body,
A first layer formed of a thermoplastic fluororesin that does not contain an adhesive functional group;
A second layer formed on the inner peripheral surface of the first layer by a thermoplastic fluororesin containing a hydroxyl group or an acid anhydride group that is an adhesive functional group activated by ultraviolet irradiation ,
A roll cover characterized in that at least an inner peripheral surface of the second layer is treated with ultraviolet rays irradiated from the outside of the first layer. The roll cover according to claim 1, wherein the ultraviolet rays are ultraviolet rays generated by a low-pressure mercury lamp. The thermoplastic fluororesin not containing the adhesive functional group is a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, and the thermoplastic fluororesin containing the adhesive functional group activated by the ultraviolet irradiation is a hydroxyl group Alternatively, the roll cover according to claim 1 or 2, which is a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer containing an acid anhydride group.

Images