OA roller

Abstract

To suppress adhesion failure on an interface between a base material layer and an elastomer layer, in a roller for OA comprising the base material layer containing pigments for absorbing ultraviolet light, and the elastomer layer containing ultraviolet light curable elastomer.SOLUTION: A roller 10 for OA comprises: a conductive shaft 12; a base material layer 14 formed on an outer peripheral surface of the shaft 12; a primer layer 16 formed on an outer peripheral surface of the base material layer 14; and an elastomer layer 18 formed on an outer peripheral surface of the primer layer 16. The base material layer 14 contains: a foamed resin; and a pigment that is dispersed in the foamed resin and absorbs ultraviolet rays. The primer layer 16 contains a non-UV curable elastomer. The elastomeric layer 18 contains an ultraviolet curable elastomer. The base material layer 14 may further contain an ion conductive agent A. The elastomer layer 18 may further contain an ion conductive agent B.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a roller for OA equipment, and more particularly, to a roller for OA equipment used in various OA equipment such as copiers, facsimiles, laser printers, etc.

Background Art

[0002] In electrophotographic image formation, generally, (a) The surface of an organic photoreceptor (OPC) drum is uniformly charged using a charging roller, (b) The charged OPC drum is irradiated with a laser, and by canceling the charge in the irradiated area, an electrostatic latent image is formed on the surface of the OPC drum, (c) Toner is electrostatically attached (developed) to the surface of the OPC drum using a developing roller, (d) The toner is transferred from the surface of the OPC drum to the surface of paper using a transfer roller, (e) The toner is fixed to the paper using a fixing roller This is done.

[0003] Thus, in an image forming apparatus using the electrophotographic method, various rollers such as a charging roller, a developing roller, a transfer roller, a fixing roller, etc. (hereinafter, these are also collectively referred to as "rollers for OA equipment") are used. Rollers for OA equipment generally include a metal shaft and an elastic layer formed on the surface of the metal shaft. The elastic layer generally consists of a polymer elastic foam with low hardness. Another layer having predetermined characteristics may be formed on the surface of the elastic layer. For example, when the roller surface consists of a polymer elastic foam with low hardness, toner may adhere to the roller surface, which may cause toner filming (a phenomenon where toner thinly adheres to the surface of the photoreceptor drum). In such a case, a solid layer for reducing the friction coefficient may be formed on the surface of the elastic layer.

[0004] Regarding such rollers for OA equipment and their manufacturing methods, various proposals have been made conventionally. For example, in Patent Document 1, (a) Form an elastic layer composed of a foam layer and a skin layer on the surface of a metal shaft. (b) Apply an ultraviolet-curable resin composition to the surface of the skin layer to a thickness of 100 μm. (c) Cure the coating film by irradiating it with ultraviolet light to form a solid layer. A method for manufacturing a foam roller is disclosed.

[0005] In the same document, (A) When forming a solid layer by applying a solvent-based paint or a water-based paint and drying it with hot air, a long drying line is required, and the quality of the solid layer is not stable. Also, (B) When forming a solid layer using an ultraviolet-curable resin composition, a long drying line is not required, and the quality is stabilized. is described.

[0006] Patent Document 2 discloses a roller for an image forming apparatus obtained by forming a foamed resin layer on the outer peripheral surface of a shaft and forming a net-like resin layer on the outer peripheral surface of the foamed resin layer. The same document describes that when using such a roller for an image forming apparatus as a cleaning roller, the scraping property of toner adhering to the cleaning target portion is improved.

[0007] Patent Document 3 discloses (a) Apply an adhesive made of an ultraviolet-curable resin to the outer peripheral surface of a shaft. (b) Insert the shaft through a through-hole of a cylindrical elastic body made of a material that transmits ultraviolet light. (c) Irradiate the outer surface of the elastic body with ultraviolet light to cure the adhesive. The roller obtained thereby is disclosed. The same document describes that using such a method can simplify the work required for adhering the elastic body and the shaft.

[0008] Furthermore, Patent Document 4 discloses (a) Prepare a composition containing a urethane prepolymer having an allyl group, vinyl ether group, or acrylate group as a terminal functional group, a polythiol, and a conductive agent. (b) Apply the above composition to the surface of a metal shaft to a thickness of 1 mm. (c) Irradiate the surface of the coating film with ultraviolet light to cure the coating film. (d) Using a cylindrical grinding machine, grind the surface of the cured coating film to form an elastic layer with a thickness of 0.5 mm on the surface of the metal shaft. A charging roller obtained by the above is disclosed. The same document describes that by such a method, an elastic layer can be formed without using acrylic-based blending raw materials.

[0009] Among OA rollers, for transfer rollers, developing rollers, charging rollers, etc., conductivity is required. When the elastic layer (base material layer) formed on the surface of a metal shaft consists only of a foamed resin, the conductivity is insufficient, so a conductive agent is usually added to the elastic layer. Also, when the outermost surface of the elastic layer consists of a foamed resin, due to insufficient electrostatic force in the pore part, there may occur a phenomenon where toner is partially not transferred and a part of the image is missing (a dropout phenomenon). Therefore, a surface layer (elastomer layer) containing no pores is formed on the outermost surface of the elastic layer (base material layer) consisting of a foamed resin.

[0010] When forming an elastomer layer on the surface of the base material layer, if an ultraviolet-curable elastomer is used as the elastomer layer, the elastomer layer can be formed in a short time. However, when the conductive agent contained in the base material layer is a pigment that absorbs ultraviolet light such as carbon, using an ultraviolet-curable elastomer as the elastomer layer causes a problem that poor curing occurs at the interface between the base material layer and the elastomer layer, and sufficient adhesive strength cannot be ensured. On the other hand, in order to solve this problem, when using a non-ultraviolet-curable elastomer such as a heat-curable elastomer or a moisture-curable elastomer as the elastomer layer, there is a problem that it takes a long time for curing.

Prior Art Documents

Patent Documents

[0011]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0012] The problem to be solved by the present invention is to suppress poor adhesion at the interface between a base material layer containing a pigment that absorbs ultraviolet rays and an elastomer layer containing an ultraviolet curable elastomer in an OA roller.

Means for Solving the Problems

[0013] To solve the above problems, the OA roller according to the present invention has a conductive shaft, a base material layer formed on the outer peripheral surface of the shaft, a primer layer formed on the outer peripheral surface of the base material layer, and an elastomer layer formed on the outer peripheral surface of the primer layer and is provided with, the base material layer contains a foamed resin and a pigment that absorbs ultraviolet rays dispersed in the foamed resin, the primer layer contains a non-ultraviolet curable elastomer, and the elastomer layer contains an ultraviolet curable elastomer.

Effects of the Invention

[0014] On the outer peripheral surface of a base material layer containing a pigment that absorbs ultraviolet rays and a foamed resin, when the raw material of an ultraviolet curable elastomer is directly applied and the coating film is irradiated with ultraviolet rays, poor curing of the raw material occurs in the vicinity of the interface between the base material layer and the elastomer layer. This is presumably because the pigment absorbs ultraviolet rays or shields ultraviolet rays in the vicinity of the interface between the base material layer and the elastomer layer, so that a sufficient amount of ultraviolet rays is not irradiated to the raw material in the vicinity of the interface.

[0015] On the other hand, when forming an elastomer layer containing an ultraviolet curable elastomer on the outer peripheral surface of a base material layer containing a pigment that absorbs ultraviolet rays and a foamed resin, if a primer layer is interposed between the base material layer and the elastomer layer, poor curing of the raw material of the ultraviolet curable elastomer is suppressed. This is presumably because by forming a primer layer on the outer peripheral surface of the base material layer, absorption or shielding of ultraviolet rays by the pigment is suppressed in the vicinity of the interface between the primer layer and the elastomer layer. Furthermore, compared with the case where the entire elastomer layer and primer layer are produced using a non-ultraviolet curable elastomer such as a thermosetting elastomer or a moisture-curing elastomer, the curing time can be shortened.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

[0017] Hereinafter, an embodiment of the present invention will be described in detail. [1. Roller for OA] FIG. 1 shows a front view (left figure) of the roller for OA according to the present invention and a cross-sectional view taken along the line A-A' (right figure). In FIG. 1, the roller for OA 10 includes a conductive shaft 12, a base material layer 14 formed on the outer peripheral surface of the shaft 12, A primer layer 16 formed on the outer peripheral surface of the base material layer 14, and an elastomer layer 18 formed on the outer peripheral surface of the primer layer 16 are provided. An OC layer (not shown) may be further formed on the surface of the elastomer layer 18.

[0018] [1.1. Shaft] The shaft 12 is made of a conductive material. The material of the shaft 12 is not particularly limited as long as it has conductivity. Examples of the material of the shaft 12 include, (a) metals such as stainless steel, aluminum alloy, copper alloy, and magnesium alloy, (b) a composite material in which a conductive agent is dispersed in a matrix made of resin, (c) a composite material in which a conductive film is formed on the surface of resin and the like. In particular, the shaft 12 is preferably a metal shaft. This is because a metal shaft has higher conductivity and strength and lower cost compared to shafts made of other materials.

[0019] The diameter and length of the shaft 12 are not particularly limited, and optimal values can be selected according to the purpose. The shaft 12 may be a solid shaft or a hollow shaft.

[0020] [1.2. Base material layer] A base material layer 14 is formed on the outer peripheral surface of the shaft 12. In the present invention, the base material layer 14 includes a foamed resin and a pigment that absorbs ultraviolet rays and is dispersed in the foamed resin. The base material layer 14 may consist only of the foamed resin and the pigment, or may further contain an ionic conductive agent A in addition to these.

[0021] [1.2.1. Material] [A. Foamed resin] In the present invention, the type of the foamed resin is not particularly limited. Examples of the material of the foamed resin include polyurethane, silicone rubber, ethylene-propylene-diene rubber (EPDM), acrylonitrile-butadiene rubber (NBR), natural rubber, styrene-butadiene rubber (SBR), butadiene rubber, isoprene rubber, polynorbornene rubber, butyl rubber, chloroprene rubber, acrylic rubber, epichlorohydrin rubber (ECO), ethylene-vinyl acetate copolymer (EVA), and the like.

[0022] Among these, the foamed resin is preferably foamed polyurethane. The OA roller 10 repeatedly makes contact with and separates from an object at high speed during use, and accordingly repeatedly deforms and recovers. At this time, if the restoring force on the surface of the OA roller 10 is weak, the OA roller 10 in a state where the surface is dented may come into contact with the next object, and horizontal white streaks or color unevenness may occur in the image. Since foamed polyurethane has a greater restoring force than other materials, it has the advantage that such white streaks and color unevenness are less likely to occur. Further, foamed polyurethane also has the advantage of excellent abrasion resistance.

[0023] In the present invention, the density of the foamed resin is not particularly limited, and an optimal value can be selected according to the purpose. Generally, if the density becomes too small, it may be difficult to hold the primer raw material on the surface of the base material layer 14 when the liquid primer raw material is applied to the surface of the base material layer 14. Therefore, the density is preferably 35 kg / m 3 or more. On the other hand, if the density becomes too large, it may be difficult to manufacture the foamed resin. Therefore, the density is preferably 800 kg / m 3 or less. The density is more preferably 720 kg / m 3 or less. In the present invention, the "density of the base material layer 14" refers to the density of the foamed resin containing a pigment and, if necessary, an ion conductive agent A added thereto.

[0024] The air bubbles contained in the foamed resin are preferably closed cells. This is because when forming the primer layer 16 on the surface of the base material layer 14, it is difficult for the raw material of the primer layer 16 to penetrate into the interior of the foamed resin. Furthermore, it is preferable that the surface of the base material layer 14 has small irregularities. This is because the smaller the irregularities on the surface of the base material layer 14, the easier it is to fill the recesses on the surface of the base material layer 14 with the primer.

[0025] [B. Pigment] The base material layer 14 contains a pigment dispersed in the foamed resin. "The pigment is dispersed in the foamed resin" means (a) the pigment is filled in the gaps between the polymer chains constituting the foamed resin, and / or (b) the pigment is filled in the air bubbles of the foamed resin .

[0026] The pigment is mainly added to color the base material layer 14 in a desired color so that the discoloration (yellowing) of the foamed resin is not noticeable, and to control the conductivity of the base material layer 14. In the present invention, the pigment is made of a material that absorbs ultraviolet rays. The pigment may be a material having high conductivity, or may be a material having no high conductivity. Examples of the pigment include (a) carbon, (b) metal powders such as aluminum, copper, and nickel, (c) conductive metal oxide powders such as tin oxide, titanium oxide, and zinc oxide, and so on. In particular, carbon is preferable as the pigment. This is because the yellowing becomes less noticeable due to the base material layer 14 being colored black, and the conductivity of the base material layer 14 can be controlled relatively easily.

[0027] There are various materials of carbon with different shapes and conductivities. Examples of carbon include (a) Carbon blacks with large structures such as acetylene black and ketjen black, which have a large function of enhancing the conductivity of the base material layer 14 (hereinafter, these are also collectively referred to as "conductive carbon"), (b) Carbon blacks with small structures such as furnace black, which have a small function of enhancing the conductivity of the base material layer 14 (hereinafter, these are also collectively referred to as "pigment carbon"), (c) Graphite powder, (d) Carbon fiber and the like.

[0028] [C. Ion Conductive Agent A] When the OA roller 10 is used as a transfer roller, for example, the base material layer 14, the primer layer 16, and the elastomer layer 18 require a predetermined conductivity. When the required conductivity of the OA roller 10 can be obtained only by adding a pigment to the base material layer 14 and optimizing the primer layer 16 and the elastomer layer 18 (including optimizing the thickness of each layer), the ion conductive agent A is not necessarily required. On the other hand, when the required conductivity of the OA roller 10 cannot be obtained only by adding a pigment to the base material layer 14 and optimizing the primer layer 16 and the elastomer layer 18, it is preferable to add the ion conductive agent A to the base material layer 14.

[0029] In the present invention, the material of the ion conductive agent A added to the base material layer 14 is not particularly limited. As the ion conductive agent A, for example, (a) Perchlorates, chlorates, hydrochlorides, bromates, iodates, borofluoroacid salts, sulfates, ethyl sulfates, carboxylates, sulfonates and other ammonium salts of tetraethylammonium, tetrabutylammonium, dodecyltrimethylammonium (for example, lauryltrimethylammonium), hexadecyltrimethylammonium, octadecyltrimethylammonium (for example, stearyltrimethylammonium), benzyltrimethylammonium, modified fatty acid dimethylethylammonium, etc., (b) Perchlorates, chlorates, hydrochlorides, bromates, iodates, borofluoroacid salts, trifluoromethylsulfates, sulfonates of alkali metals such as lithium, sodium, potassium, calcium, magnesium and alkaline earth metals, (c) Having imidazolium-based ions, pyridinium-based ions, pyrrolidinium-based ions, piperidinium-based ions, phosphonium-based ions as cation species, and having halogen-based ions such as chlorine, bromine, iodine, borate-based ions such as tetrafluoroborate ion, phosphate-based ions such as hexafluorophosphate ion, sulfate-based ions such as bis(trifluoromethanesulfonyl)imide ion as anion species and the like.

[0030] [1.2.2. Content] The content of the pigment contained in the base material layer 14 is not particularly limited, and an optimum content can be selected according to the type of the pigment, the presence or absence of the ionic conductive agent A, the use of the roller 10 for OA, etc. Similarly, when the base material layer 14 contains the ionic conductive agent A, the content of the ionic conductive agent A is not particularly limited, and an optimum content can be selected according to the type of the pigment, the use of the roller 10 for OA, etc.

[0031] Generally, if the content of the pigment is too small, yellowing tends to be prominent, or the intended conductivity may not be obtained. Therefore, the content of the pigment is preferably 0.4 mass% or more. On the other hand, if the content of the pigment is excessive, the viscosity of the raw material containing the same may increase excessively, and the production of the base material layer 14 may be difficult. Also, if the content of the pigment is excessive, the base material layer 14 may become brittle. Therefore, the content of the pigment is preferably 19.6 mass% or less.

[0032] The content of the ionic conductive agent A is not particularly limited, and an optimal content can be selected according to the purpose. Generally, the higher the content of the ionic conductive agent A, the higher the conductivity obtained. On the other hand, when the content of the ionic conductive agent A becomes excessive, the mechanical properties of the base material layer 14 may decrease. Specifically, the content of the ionic conductive material A is preferably 0.01 mass% or more and 10.0 mass% or less.

[0033] [1.2.3. Thickness] The thickness of the base material layer 14 is not particularly limited, and an optimal thickness can be selected according to the purpose. The thickness of the base material layer 14 is usually about 1 mm to 10 mm.

[0034] [1.3. Primer layer] A primer layer 16 is formed on the outer peripheral surface of the base material layer 14. The primer layer 16 is inserted between the base material layer 14 and the elastomer layer 18 in order to suppress poor curing of the elastomer layer 18.

[0035] [1.3.1. Material] In the present invention, the primer layer 16 contains a non-ultraviolet-curable elastomer. The "non-ultraviolet-curable elastomer" refers to an elastomer that can be cured without being irradiated with ultraviolet rays.

[0036] Examples of the non-ultraviolet-curable elastomer include (a) thermosetting and solvent-volatile elastomers such as polyurethane-based elastomers, acrylic-based elastomers, and styrene-based elastomers, (b) undercoat paints such as acrylic-based, ethylene vinyl acetate-based, urethane-based, and epoxy-based paints and the like. The material of the primer layer 16 is particularly preferably a polyurethane-based elastomer. This is because the glass transition temperature and temperature dependence of viscoelasticity of the polyurethane-based elastomer may be close to those of the materials used for the base material layer 14 and the elastomer layer 18.

[0037] The material of the primer layer 16 may consist only of a non-UV-curable elastomer as long as it can prevent the material of the uncured elastomer layer 18 from coming into contact with the base material layer 14, or it may contain other components. Examples of other components include materials that impart conductivity, such as metal powder and ion conductive agents, which do not absorb ultraviolet light.

[0038] However, it is necessary that the primer layer 16 does not contain a pigment that absorbs ultraviolet light. This is because if the primer layer 16 contains a pigment that absorbs ultraviolet light, it becomes difficult to cure the raw material of the elastomer layer 18 by ultraviolet light. Note that the primer layer 16 may be a foamed material or a non-foamed material. However, when the primer layer 16 is a foamed material, if the raw material of the elastomer layer 18 soaks into the bubbles of the primer layer 16 and the raw material of the elastomer layer 18 comes into contact with the base material layer 14, the curing of the raw material may be insufficient. In order to suppress such infiltration of the raw material, the primer layer 16 is preferably a non-foamed material.

[0039] [1.3.2. Thickness] As described later, the primer layer 16 is formed by applying the raw material of the primer layer 16 to the surface of the base material layer 14 and curing the coating film. In this case, since the base material layer 14 contains bubbles, a part of the raw material of the primer layer 16 may soak into the bubbles of the base material layer 14 and the raw material may cure in the bubbles. In the present invention, the "thickness of the primer layer 16" refers to the distance from the outermost surface of the base material layer 14 to the outermost surface of the primer layer 16, and does not include the thickness of the region where the raw material of the primer layer 16 has soaked into the bubbles of the base material layer 14 and cured.

[0040] The thickness of the primer layer 16 affects the performance and cost of the roller 10 for OA. If the thickness of the primer layer 16 is too thin, curing defects may occur when forming the elastomer layer 18. Therefore, the thickness of the primer layer 16 is preferably more than 0 mm. More preferably, the thickness is 0.2 mm or more. On the other hand, if the thickness of the primer layer 16 is too thick, it may take a long time for the curing process of the primer layer 16 and the manufacturing cost may increase. Therefore, the thickness of the primer layer 16 is preferably 0.8 mm or less.

[0041] [1.4. Elastomer layer] An elastomer layer 18 is formed on the outer peripheral surface of the primer layer 16. The elastomer layer 18 is formed to suppress the shortage of the electrostatic force caused by the unevenness of the base material layer 14. In the present invention, the elastomer layer 18 contains an ultraviolet curable elastomer. The elastomer layer 18 may be composed only of an ultraviolet curable elastomer, or may further contain an ion conductive agent B in addition to this.

[0042] [1.4.1. Material] [A. Ultraviolet curable elastomer] The elastomer layer 18 contains an ultraviolet curable elastomer. The ultraviolet curable elastomer is not particularly limited as long as it can be cured using ultraviolet rays. There are ultraviolet curable elastomers that exhibit relatively high conductivity and those that exhibit relatively low conductivity. Any of them may be used as the material of the elastomer layer 18.

[0043] The elastomer layer 18 particularly contains a urethane prepolymer having an allyl group, a vinyl ether group, or an acrylate group as a terminal functional group and a polythiol having a thiol group, and is applied to the surface of the primer layer. The coating film made of the raw material is irradiated with ultraviolet rays to cause an enethiol reaction. Those containing an elastomer obtained in this way are preferred. In order to effectively carry out the reaction between an allyl group or the like and a thiol group, it is preferable to add a photopolymerization initiator to the raw materials. The elastomer layer 18 obtained by such a method has advantages such as a lower cost of equipment for curing, the ability to miniaturize the equipment for curing, and the ability to shorten the time required for curing, as compared with non-UV-curable elastomers.

[0044] Examples of materials for the elastomer layer 18 other than those described above include compositions containing a (meth)acrylate oligomer and a UV polymerization initiator.

[0045] [B. Ion Conductive Material B] As described above, when applying the OA roller 10 to a transfer roller, for example, the base material layer 14, the primer layer 16, and the elastomer layer 18 need to have a predetermined conductivity. When the required conductivity for the OA roller 10 can be obtained only by optimizing the material of the UV-curable elastomer constituting the elastomer layer 18 and by optimizing the base material layer 14 and the primer layer 16 (including optimizing the thickness of each layer), the ion conductive agent B is not necessarily required. On the other hand, when the required conductivity for the OA roller 10 cannot be obtained only by optimizing the material of the UV-curable elastomer and by optimizing the base material layer 14 and the primer layer 16, it is preferable to add the ion conductive agent B to the elastomer layer 18.

[0046] In the present invention, the material of the ion conductive agent B added to the elastomer layer 18 is not particularly limited. When the base material layer 14 contains the ion conductive material A, the ion conductive material B may be the same material as the ion conductive material A or a different material. Since other aspects regarding the ion conductive material B are the same as those of the ion conductive agent A, the description thereof is omitted.

[0047] [1.4.2. Content] When the elastomer layer 18 contains the ionic conductive agent B, the content of the ionic conductive agent B is not particularly limited, and an optimal content can be selected according to the type of the ultraviolet curable elastomer, the use of the roller 10 for OA, etc.

[0048] Generally, when the content of the ionic conductive agent B is too small, the conductivity may decrease. Therefore, the content of the ionic conductive agent B is preferably 0.05 mass% or more. On the other hand, when the content of the ionic conductive agent B is excessive, the mechanical properties of the elastomer layer 18 may decrease. Therefore, the content of the ionic conductive agent B is preferably 10.0 mass% or less.

[0049] [1.4.3. Thickness] The thickness of the elastomer layer 18 is not particularly limited, and an optimal thickness can be selected according to the purpose. Generally, when the thickness of the elastomer layer 18 is too thin, the elastomer layer 18 may peel off when the surface of the elastomer layer 18 is polished after curing the elastomer layer 18. Therefore, the thickness of the elastomer layer 18 is preferably 0.5 mm or more. On the other hand, even if the thickness of the elastomer layer 18 is made thicker than necessary, there is no difference in the effect and there is no practical benefit. Therefore, the thickness of the elastomer layer 18 is preferably 5.0 mm or less. The thickness is more preferably 4.0 mm or less.

[0050] [1.5. OC layer] An OC layer (not shown) may be further formed on the surface of the elastomer layer 18. Here, the "OC layer" refers to a layer (surface coating layer) formed on the surface of the elastomer layer 18 for the purpose of giving the roller 10 for OA antifouling properties. The material of the OC layer is not particularly limited, and an optimal material can be used according to the purpose. Examples of the material of the OC layer include aqueous urethane paints. Also, the thickness of the OC layer is not particularly limited, and an optimal thickness can be selected according to the purpose. Specifically, the thickness of the OC layer is preferably 0.5 μm to 40 μm.

[0051] [1.6. Conductivity (Volume Resistivity) of the OA Roller] The "volume resistivity" refers to the value calculated from the current value flowing between the outermost surfaces of the roller 10 for shaft 12 - OA when a current is passed between the outermost surfaces of the roller 10 for shaft 12 - OA under the conditions of temperature: 22°C ± 3°C, relative humidity: 55% ± 5%, and voltage: 100V. The volume resistivity of the OA roller 10 can be controlled by the composition and thickness of each layer.

[0052] The volume resistivity of the OA roller 10 is not particularly limited, and an optimal value can be selected according to the purpose. Specifically, the volume resistivity of the OA roller 10 is preferably 3 (logΩ) or more and 10 (logΩ) or less.

[0053] [1.7. Applications] The OA roller 10 according to the present invention can be used in various applications. The OA roller 10 according to the present invention can be used, for example, as a transfer roller, a charging roller, a toner supply roller, a developing roller, a fixing roller, a paper feed roller, a paper discharge roller, and the like.

[0054] [2. Manufacturing Method of the OA Roller] The OA roller 10 according to the present invention is (a) forming a base material layer 14 on the outer peripheral surface of the shaft 12, (b) forming a primer layer 16 on the outer peripheral surface of the base material layer 14, (c) forming an elastomer layer 18 on the outer peripheral surface of the primer layer 16, (d) further forming an OC layer on the outer peripheral surface of the elastomer layer 18 if necessary and can be manufactured thereby.

[0055] [2.1. First Step] First, a base material layer 14 is formed on the outer peripheral surface of the shaft 12 (first step). In the present invention, the method for forming the base material layer 14 is not particularly limited. As a method for forming the base material layer 14, for example, (a) A method of producing a cylindrical foam containing a foamed resin, inserting a shaft into the through-hole of the foam, and bonding the foam and the shaft. (b) A method of vertically installing a shaft at the center of a cylindrical mold, pouring a raw material of a foamed resin into the gap between the inner wall surface of the mold and the shaft, and foaming and curing the raw material in the mold. There are such methods.

[0056] In addition, as a method for producing a foam containing a pigment and / or an ion conductive agent A, for example, (a) A method of adding a pigment and / or an ion conductive agent A to a raw material of a foamed resin in advance and foaming and curing the raw material. (b) A method of producing a foam using a raw material of a foamed resin that does not contain a pigment and an ion conductive agent A, immersing the foam in a dispersion liquid in which a pigment and / or an ion conductive agent A is dispersed, pulling the foam out of the dispersion liquid, and drying it. There are such methods.

[0057] The composition of the raw material for producing the foamed resin is not particularly limited, and an optimal composition can be selected according to the type of the foamed resin. For example, when the foamed resin is made of foamed polyurethane, it is preferable to use a raw material in which a polyol, an isocyanate, a foam stabilizer, a resinification catalyst, a pigment, and an ion conductive agent A are blended in a predetermined ratio. By mechanically foaming and curing by mixing such a raw material with an inert gas blown in using a mixer, a foam made of foamed polyurethane containing a predetermined amount of a pigment and an ion conductive agent A can be produced.

[0058] Alternatively, a raw material in which a polyol, an isocyanate, a foam stabilizer, a resinification catalyst, a foaming agent, a foaming catalyst, a pigment, and an ion conductive agent A are blended in a predetermined ratio may be used. When such a raw material is poured into a mold and heated to a predetermined temperature, foaming and curing occur, and a foam made of foamed polyurethane containing a predetermined amount of a pigment and / or an ion conductive agent A can be produced.

[0059] [2.2. Second Step] Next, a primer layer 16 is formed on the outer peripheral surface of the base material layer 14. In the present invention, the method for forming the primer layer 16 is not particularly limited. Examples of the method for forming the primer layer 16 include (a) A method in which a solvent-soluble elastomer is dissolved in a solvent such as water or an organic solvent, the solution is applied to the surface of the base material layer 14, and the coating film is dried. (b) A method in which a low-viscosity liquid elastomer is applied to the surface of the base material layer 14, and the coating film is cured (addition curing, condensation curing) by heat, moisture, or the like. and the like.

[0060] [2.3. Third step] Next, an elastomer layer 18 is formed on the outer peripheral surface of the primer layer 16. Specifically, the elastomer layer 18 is (a) formed by applying a raw material of an ultraviolet-curable elastomer to the surface of the primer layer 18, (b) irradiating the coating film with ultraviolet rays to cure it. It can be produced by

[0061] The composition of the raw material for forming the elastomer layer 18 is not particularly limited, and it is preferable to select an optimal composition according to the type of the ultraviolet-curable elastomer. For example, when the elastomer layer 18 contains an elastomer obtained by photopolymerizing a urethane prepolymer and a polythiol, (a) a urethane prepolymer having an allyl group, a vinyl ether group, or an acrylate group as a terminal functional group, (b) a polythiol having a thiol group, (c) a photopolymerization initiator, and (d) an ionic conductive agent B are preferably blended in a predetermined ratio. When such a raw material is applied to the surface of the primer layer 16 and the coating film is irradiated with ultraviolet rays to cure it, the elastomer layer 18 can be formed.

[0062] In this case, a urethane prepolymer having an allyl group, a vinyl ether group, or an acrylate group as a terminal functional group can be produced by adding a compound having an allyl group, a vinyl ether group, or an acrylate group to a urethane prepolymer synthesized from a polyol and an isocyanate. Examples of the polythiol include esters of mercaptocarboxylic acids and polyhydric alcohols, fatty acid polythiols, aromatic polythiols, and the like. Examples of the photopolymerization initiator include acetophenone-based compounds, benzophenone-based compounds, thioxanthone-based compounds, and the like. When these raw materials are irradiated with ultraviolet light, the urethane prepolymer and the polythiol undergo an enethiol reaction to form an elastomer. After curing, the surface of the elastomer layer is polished using a cylindrical grinding machine to adjust the shape.

[0063] [4. Fourth Step] Next, if necessary, an OC layer (surface coating layer) is formed on the surface of the elastomer layer 18. The method for forming the OC layer is not particularly limited, and an optimal method can be selected according to the purpose.

[0064] [3. Function] FIG. 2 shows a schematic diagram of a conventional method for manufacturing a roller for OA equipment. First, as shown in FIG. 2(A), a base material layer 14 is formed on the outer peripheral surface of a shaft 12. The base material layer 14 is composed of a foamed resin 14a in which a pigment 14b that absorbs ultraviolet light is dispersed. Next, as shown in FIG. 2(B), a raw material 18a of an ultraviolet curable elastomer is directly applied to the outer peripheral surface of the base material layer 14. Since the base material layer 14 contains the foamed resin 14a, a part of the raw material 18a penetrates into the base material layer 14.

[0065] When the raw material 18a is irradiated with ultraviolet rays in this state, the raw material 18a located above the base material layer 14 is cured by the ultraviolet rays to become the elastomer layer 18. However, near the interface between the base material layer 14 and the elastomer layer 18, poor curing of the raw material 18a occurs. This is presumably because near the interface between the base material layer 14 and the elastomer layer 18, the pigment 14b absorbs the ultraviolet rays or shields the ultraviolet rays, so that a sufficient amount of ultraviolet rays is not irradiated to the raw material 18a near the interface.

[0066] FIG. 3 shows a schematic diagram of a method for manufacturing a roller for OA according to the present invention. First, as shown in FIG. 3(A), a base material layer 14 is formed on the outer peripheral surface of the shaft 12. The base material layer 14 is composed of a foamed resin 14a in which a pigment 14b that absorbs ultraviolet rays is dispersed. Next, as shown in FIG. 3(B), a raw material 16a of a primer layer is applied to the outer peripheral surface of the base material layer 14. Since the base material layer 14 contains the foamed resin 14b, a part of the raw material 16a soaks into the base material layer 14. After applying the raw material 16a, when the solvent is volatilized or heat or moisture is applied, the raw material 16a is cured and the primer layer 16 is formed.

[0067] Furthermore, as shown in FIG. 3(C), a raw material 18a of an ultraviolet-curable elastomer is applied to the outer peripheral surface of the primer layer 16. When the primer layer 16 substantially does not contain air bubbles or when the thickness of the primer layer 16 is sufficiently thick, the raw material 18a does not soak into the primer layer 16 and the base material layer 14. When the raw material 18a is irradiated with ultraviolet rays in this state, the raw material 18a is cured by the ultraviolet rays to become the elastomer layer 18.

[0068] In the case where an elastomer layer 18 containing an ultraviolet curable elastomer is formed on the outer peripheral surface of a base material layer 14 containing a pigment 14b that absorbs ultraviolet rays and a foamed resin 14a, a primer layer 16 is interposed between the base material layer 14 and the elastomer layer 18. Therefore, poor curing of the raw material 18a of the ultraviolet curable elastomer is suppressed. This is presumably because by forming the primer layer 16 on the outer peripheral surface of the base material layer 14, absorption or shielding of ultraviolet rays by the pigment 14b is suppressed in the vicinity of the interface between the primer layer 16 and the elastomer layer 18. Furthermore, compared with the case where the entire elastomer layer 18 and primer layer 16 are produced using a non-ultraviolet curable elastomer such as a thermosetting elastomer or a moisture-curing elastomer, the curing time can be shortened.

Example

[0069] (Examples 1 to 6, Comparative Examples 1 to 7) [1. Preparation of Samples] [1.1. Examples 1 to 6, Comparative Examples 1 to 6] [1.1.1. Preparation of Base Material Layer] First, a foam (slab) serving as the base material layer was produced. Next, the foam was cut into strips of the size of one roll (with holes formed for inserting a shaft). A shaft with an adhesive was inserted into the holes of the strips, and the shaft and the strips were adhered. Further, the outer peripheral surface of the strips was polished using a cylindrical grinding machine to obtain a cylindrical base material layer. For the foam serving as the base material layer, foamed polyurethane was used. The details of the method for producing the foam are as follows.

[0070] [A. ENDUR (Mechanically Foamed Polyurethane Foam)] A polyol, an isocyanate, a foam stabilizer, and a resinification catalyst were mixed at a predetermined ratio. To this raw material mixture, a predetermined amount of a pigment and / or an ion conductor A was further added as necessary. As the ion conductor A, a perchlorate of tetraalkylammonium was used. The raw material mixture was foamed and cured by mixing it with a mixer while blowing an inert gas into the raw material mixture, and a foam (manufactured by Inoac Corporation, equivalent to ENDUR) was obtained. The density of the obtained foamed polyurethane was 12 - 50 pcf (192 kg / m 3 ~ 800 kg / m 3 ), and the Asker C hardness was 10 - 50°. Also, the thickness of the base material layer after cylindrical polishing was 3.5 - 5.5 mm.

[0071] [B. UEM - 55 (Slab Urethane Foam A)] A polyol, an isocyanate, a foam stabilizer, water (a foaming agent), a resinification catalyst, and a foaming catalyst were mixed at a predetermined ratio. To this mixture, a predetermined amount of ionic conductor A was further added as necessary. The raw material mixture was poured into a mold and foamed to obtain a foam (manufactured by Inoac Corporation, equivalent to UEM - 55). As the ionic conductor A, a perchlorate of tetraalkylammonium was used. Next, for some of the foams, pigments were added by an impregnation method. That is, the foam (slab) was made into a sheet, the sheet was cut, and further, after making holes for inserting shafts in the sheet, the sheet was immersed in a dispersion in which the pigment was dispersed in water. After a predetermined time had passed, the sheet was pulled out of the dispersion and dried. The density of the obtained foamed polyurethane was 50 - 75 kg / m 3 , and the FP hardness was 40 - 80°. Also, the thickness of the base material layer after cylindrical polishing was 3.5 - 5.5 mm.

[0072] [C. EP - 70 (Slab Urethane Foam B)] The block of EP - 70 manufactured by Inoac Corporation was sliced into 40 - mm pieces. Next, the obtained sheet was cut into a width of 40 mm × a length of 370 mm. Further, a hole with a diameter of φ13 mm was formed from the center of one end face (the 40 mm × 40 mm face) to the center of the other end face of the obtained strip (40 mm × 40 mm × 370 mm). Next, the perforated strip was immersed in a dispersion obtained by dispersing the strip in water together with a pigment and a component (binder) for adhering the pigment to urethane, so that the dispersion was impregnated into the bubbles in the strip. Thereafter, the strip was pulled out from the dispersion and dried at a temperature of 100 °C or higher. Next, hot melt was applied to a separately prepared metal shaft and inserted into the holes of the strip. Subsequently, the strip with the shaft inserted was heated to a temperature equal to or higher than the temperature at which the hot melt melts. After heating for a predetermined time, the strip with the shaft inserted was cooled to near room temperature. Furthermore, the outer peripheral surface of the strip was polished using a cylindrical polishing machine. The thickness of the base material layer after cylindrical polishing was 3.5 to 5.5 mm.

[0073] [1.1.2. Preparation of primer layer] For Examples 1 to 6, a primer layer was formed on the outer peripheral surface of the base material layer. As the raw material of the primer layer, a solvent-volatile urethane-based primer (manufactured by Tosoh Corporation, Niporan (registered trademark) 5230) was used. A predetermined amount of the urethane-based primer was applied to the outer peripheral surface of the base material layer and dried. The thickness of the obtained primer layer was 0.2 to 0.8 mm.

[0074] [1.1.3. Preparation of elastomer layer] Next, an elastomer layer was formed on the outer peripheral surface of the primer layer (Examples 1 to 6) or the outer peripheral surface of the base material layer (Comparative Examples 1 to 6). An ultraviolet-curable polyurethane elastomer was used for the elastomer layer. The details of the method for preparing the elastomer layer are as follows.

[0075] [A. SC-22 (UV-curable polyurethane elastomer A)] A polyurethane prepolymer having a methacryl group as a terminal functional group, an ionic conductive agent B, a polythiol, and a photoinitiator were mixed at a predetermined ratio. The content of the ionic conductive agent B was an amount corresponding to 3.0 mass% of the total mass of the cured elastomer layer. While rotating a roller, the raw materials were applied to the surface of the primer layer or the surface of the base material layer using a doctor blade and cured by irradiating with ultraviolet rays. After curing, the outer peripheral surface was polished with a cylindrical polishing machine to obtain an elastomer layer having a thickness of 2 mm.

[0076] For the polyurethane prepolymer, a prepolymer synthesized from AN-002 manufactured by Mitsui Chemicals, Inc. and T-80 manufactured by Tosoh Corporation was used. For the ionic conductive agent B, Elegant LD-204 manufactured by NOF Corporation was used. For the polythiol, TMMP manufactured by SC Organic Chemicals Co., Ltd. was used. For the photopolymerization initiator, Omnirad 2959 manufactured by IGM RESINS B.V. was used.

[0077] [B. SC-23 (UV-curable polyurethane elastomer B)] An elastomer layer was formed in the same manner as SC-22, except that the content of the ionic conductive agent B was set to 1.0 mass%.

[0078] [C. SC-23 modified (UV-curable polyurethane elastomer C)] An elastomer layer was formed in the same manner as SC-22, except that the content of the ionic conductive agent B was set to 0.1 mass%.

[0079] [1.1.4. Preparation of OC layer] After forming the elastomer layer, an OC layer (surface coating) was formed on the outer peripheral surface of the elastomer layer. The OC layer was formed by applying BONDERITE (registered trademark) S-FN T-862A AN manufactured by Henkel Japan so that the film thickness was 5 to 40 μm and drying it.

[0080] [1.2. Comparative Example 7] Acrylonitrile-butadiene rubber (NBR), epichlorohydrin rubber, pigment, foaming agent, crosslinking agent, vulcanization accelerator, vulcanization accelerator aid, and processing aid were mixed at a predetermined ratio to obtain a raw material composition. By extruding the obtained raw material composition, a cylindrical molded body (hereinafter also referred to as "precursor of base material layer") was adhered to the surface of the shaft. Separately from this, acrylonitrile-butadiene rubber (NBR), a vulcanization aid, a release agent, a vulcanizing agent, and a vulcanization accelerator were mixed at a predetermined ratio to obtain a raw material composition. The raw material composition was extruded to obtain a cylindrical molded body (hereinafter also referred to as an "elastomer layer precursor").

[0081] The cylindrical elastomer layer precursor was set in a cylindrical roll forming mold. Next, a shaft on which a base material layer precursor was formed was inserted into the elastomer layer precursor. In this state, the elastomer layer precursor and the base material layer precursor were heated at 160 °C for 40 minutes to crosslink and foam the raw material composition. After cooling, the shaft with the base material layer and the elastomer layer was taken out of the mold. Next, the outer peripheral surface of the elastomer layer was polished with a cylindrical grinder to obtain an elastomer layer with a thickness of 2 mm. Furthermore, an OC layer was formed on the surface of the elastomer layer in the same manner as in Example 1.

[0082] [2. Test Method] [2.1. Volume Resistivity] The volume resistivity of the roller after forming the base material layer (hereinafter also referred to as the "volume resistivity of the base material layer"), the volume resistivity of the roller after forming the elastomer layer (hereinafter also referred to as the "volume resistivity of the elastomer layer"), and the volume resistivity after further forming an OC layer (surface coating) on the surface of the elastomer layer (hereinafter also referred to as the "volume resistivity of the OC layer") were measured respectively. Note that the volume resistivity of the roller after forming the primer layer was not measured. Also, for the "volume resistance value of the base material layer" in Comparative Example 7, it was measured using a sample in which the elastomer layer was removed by cylindrical polishing after integrally forming the base material layer and the elastomer layer. The measurement conditions were temperature: 22 °C ± 3 °C, relative humidity: 55% ± 5%, and voltage: 100 V.

[0083] [2.2. Degree of Curing and Adhesiveness of the Elastomer Layer] The degree of curing and the adhesiveness of the elastomer layer were visually evaluated.

[0084] [3. Results] The results are shown in Table 1 and Table 2. In addition, the history of each sample is also shown in Table 1 and Table 2. Regarding "imparting substrate conductivity", "○" indicates that conductivity could be imparted to the substrate layer using either the pigment or the ionic conductive agent A, and "△" indicates that conductivity could not be imparted to the substrate layer using a conductive agent (i.e., carbon) that changes the substrate layer to black.

[0085] Regarding "curing of the elastomer layer", "○" indicates that the elastomer layer was sufficiently cured. "△" indicates insufficient curing of the elastomer layer at the interface on the substrate layer side. Regarding "adhesion of the elastomer layer", "○" indicates that the elastomer layer is sufficiently adhered. "×" indicates that peeling has occurred between the substrate layer and the elastomer layer.

[0086] Regarding "elastomer layer forming time", "○" indicates that curing could be achieved in a time range of 5 seconds to 600 seconds, and "×" indicates that curing required more than 600 seconds. Regarding "conductive performance of the roller", "○" indicates that the volume resistivity of the roller can be adjusted with the volume resistivity of the substrate layer and the volume resistivity of the elastomer layer, and the adjustment range of the volume resistivity of the roller is wide. "△" indicates that the adjustment range of the volume resistivity is narrow. From Table 1 and Table 2, the following can be understood.

[0087] (1) In Comparative Examples 3 to 6, the elastomer layer was not sufficiently cured. This is presumably because the carbon contained in the substrate layer absorbed or blocked ultraviolet light, so the raw materials were not sufficiently cured in the vicinity of the interface between the substrate layer and the elastomer layer. (2) In Comparative Examples 1 and 2, the elastomer layer was sufficiently cured. However, since the substrate layer did not contain a pigment (carbon), it was difficult to adjust the volume resistivity of the roller. (3) Comparative Example 7 integrally formed the base material layer and the elastomer layer, but it took a long time of 40 minutes for crosslinking and foaming (i.e., formation of the elastomer layer). Also, the restoring force of the roller obtained in Comparative Example 7 was inferior to that of a roller using urethane-based materials for the base material layer and the elastomer layer, respectively.

[0088] (4) In all of Examples 1 to 6, the elastomer layer was sufficiently cured. Also, by controlling the types and amounts of the pigment and the ionic conductive agent A added to the base material layer, the types and amounts of the ionic conductive agent B added to the elastomer layer, and the thicknesses of the respective layers, the volume resistivity of the roller could be adjusted to the target value. (5) By interposing a primer layer between the base material layer and the ultraviolet curable elastomer layer, the base material layer and the ultraviolet curable elastomer layer could be adhered regardless of the color appearance of the base material layer.

[0089]

Table 1

[0090]

Table 2

[0091] As described above in detail regarding the embodiments of the present invention, the present invention is not limited to the above embodiments at all, and various modifications are possible without departing from the gist of the present invention.

Industrial Applicability

[0092] The OA roll according to the present invention can be used for transfer rollers, charging rollers, toner supply rollers, developing rollers, fixing rollers, paper feed rollers, paper discharge rollers, and the like.

Explanation of Reference Numerals

[0093] 10 OA roll 12 Shaft 14 Base material layer 16 Primer layer 18 Elastomer layer

Claims

1. A conductive shaft, a base material layer formed on the outer peripheral surface of the shaft, a primer layer formed on the outer peripheral surface of the base material layer, and an elastomer layer formed on the outer peripheral surface of the primer layer are provided, the base material layer includes a foamed resin and a pigment that absorbs ultraviolet rays and is dispersed in the foamed resin, the primer layer includes a non-ultraviolet curable elastomer, the elastomer layer applies a raw material containing a urethane prepolymer having an allyl group, a vinyl ether group, a methacryl group, or an acrylate group as a terminal functional group and a polythiol having a thiol group onto the surface of the primer layer, irradiates ultraviolet rays onto the coating film made of the raw material to cause an enethiol reaction and includes an ultraviolet curable elastomer obtained thereby roller for OA use.

2. The roller for OA use according to claim 1, wherein the pigment is carbon.

3. The roller for OA use according to claim 1 or 2, wherein the base material layer further includes an ionic conductive agent A.

4. The roller for OA use according to any one of claims 1 to 3, wherein the primer layer includes a polyurethane-based elastomer.

5. The roller for OA use according to any one of claims 1 to 4, wherein the elastomer layer further includes an ionic conductive agent B.

6. The roller for OA use according to any one of claims 1 to 5, wherein the thickness of the elastomer layer is 0.5 mm or more and 5.0 mm or less.

7. The roller for OA use according to any one of claims 1 to 6, wherein the thickness of the primer layer is more than 0 mm and 0.8 mm or less.

8. The roller for OA use according to any one of claims 1 to 7, having a volume resistivity of 3 (log Ω) or more and 10 (log Ω) or less.

9. The roller for OA use according to any one of claims 1 to 8, wherein the roller for OA use is a transfer roller, a charging roller, a toner supply roller, a developing roller, a fixing roller, a paper feed roller, or a paper discharge roller.

Images