OA rollers

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 devices such as copiers, facsimiles, laser printers, etc.

Background Art

[0002] Image formation using the electrophotographic method generally (a) uses a charging roller to uniformly charge the surface of an organic photoreceptor (OPC) drum, (b) irradiates the charged OPC drum with a laser to cancel the charge in the irradiated area, thereby creating an electrostatic latent image on the surface of the OPC drum, (c) uses a developing roller to electrostatically adhere (develop) toner to the surface of the OPC drum, (d) uses a transfer roller to transfer the toner from the surface of the OPC drum to the surface of paper, (e) uses a fixing roller to fix the toner to the paper is performed by doing so.

[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 low-hardness polymer elastic foam. Another layer having predetermined characteristics may be formed on the surface of the elastic layer. For example, when the roller surface consists of a low-hardness polymer elastic foam, toner may adhere to the roller surface, which may cause toner filming (a phenomenon in which 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 consisting 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) The coating is cured by irradiating it with ultraviolet light to form a solid layer. A method for manufacturing foam rollers is disclosed.

[0005] The document states: (A) When a solid layer is formed by applying a solvent-based or 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, and (B) When a solid layer is formed using an ultraviolet-curable resin composition, a long drying line is not required, and the quality is also stabilized. It is stated.

[0006] Patent Document 2 discloses a roller for an image forming apparatus obtained by forming a foamed resin layer on the outer surface of a shaft and a mesh-like resin layer on the outer surface of the foamed resin layer. The document states that using such rollers for image forming apparatuses as cleaning rollers improves the ability to scrape off toner adhering to the area to be cleaned.

[0007] Patent Document 3 contains: (a) Apply an adhesive made of ultraviolet curing resin to the outer surface of the shaft, (b) Insert a shaft through a through hole in a cylindrical elastic body made of a material that transmits ultraviolet light, (c) The outer surface of the elastic material is irradiated with ultraviolet light to cure the adhesive. The resulting roller is disclosed. The document states that using this method simplifies the work required to bond the elastic body to the shaft.

[0008] Furthermore, Patent Document 4 contains, (a) Prepare a composition comprising a urethane prepolymer having an allyl group, a vinyl ether group, or an acrylate group as terminal functional groups, 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) The surface of the coating is irradiated with ultraviolet light to harden the coating, (d) Using a cylindrical polishing machine, the surface of the hardened coating is polished to form an elastic layer with a thickness of 0.5 mm on the surface of the metal shaft. A charged roller obtained by this method is disclosed. The document describes how this method can be used to form an elastic layer without using acrylic-based compounding materials.

[0009] Among rollers used in office automation, transfer rollers, developing rollers, and charging rollers require conductivity. When the elastic layer (base layer) formed on the surface of a metal shaft consists only of foamed resin, conductivity is insufficient, so a conductive agent is usually added to the elastic layer. Furthermore, when the outermost surface of the elastic layer is made of foamed resin, the electrostatic force is insufficient in the pore areas, which can cause toner to not be transferred in some areas, resulting in a phenomenon where parts of the image are missing (a phenomenon called "hollowing out"). For this reason, a surface layer (elastomer layer) that does not contain pores is formed on the outermost surface of the elastic layer (base layer) made of foamed resin.

[0010] When forming an elastomer layer on the surface of a substrate layer, using an ultraviolet-curable elastomer allows for rapid formation of the elastomer layer. However, when the conductive agent in the substrate layer is a pigment that absorbs ultraviolet light, such as carbon, using an ultraviolet-curable elastomer as the elastomer layer presents a problem: curing defects occur at the interface between the substrate layer and the elastomer layer, making it impossible to ensure sufficient adhesive strength. On the other hand, if non-UV curing elastomers such as thermosetting elastomers or moisture-curing elastomers are used as the elastomer layer to solve this problem, there is a problem that curing takes a long time. [Prior art documents]

Patent Document

[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] In order 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, the elastomer layer contains an ultraviolet curable elastomer.

Effects of the Invention

[0014] When a raw material for an ultraviolet-curable elastomer is directly applied to the outer surface of a substrate layer containing an ultraviolet-absorbing pigment and a foamed resin, and the coating is irradiated with ultraviolet light, curing defects occur near the interface between the substrate layer and the elastomer layer. This is thought to be because the pigment absorbs or blocks ultraviolet light near the interface between the substrate layer and the elastomer layer, preventing a sufficient amount of ultraviolet light from reaching the raw material near the interface.

[0015] In contrast, when forming an elastomer layer containing an UV-curable elastomer on the outer surface of a substrate layer containing a UV-absorbing pigment and a foamed resin, interposing a primer layer between the substrate layer and the elastomer layer suppresses curing defects of the raw materials for the UV-curable elastomer. This is thought to be because forming a primer layer on the outer surface of the substrate layer suppresses the absorption or shielding of UV rays by the pigment near the interface between the primer layer and the elastomer layer. Furthermore, the curing time can be shortened compared to when the entire elastomer layer and primer layer are made using non-UV-curable elastomers such as thermosetting elastomers or moisture-curing elastomers. [Brief explanation of the drawing]

[0016] [Figure 1] This is a front view (left) and a cross-sectional view (right) of the OA roller according to the present invention. [Figure 2] This is a schematic diagram of a conventional manufacturing method for rollers used in office automation equipment. [Figure 3] This is a schematic diagram of the method for manufacturing an office automation roller according to the present invention.

[0017] One embodiment of the present invention will be described in detail below. [1. Rollers for office automation equipment] Figure 1 shows a front view (left) and a cross-sectional view (right) of the OA roller according to the present invention. In Figure 1, the OA roller 10 is A conductive shaft 12, A base material layer 14 formed on the outer surface of the shaft 12, A primer layer 16 formed on the outer surface of the base material layer 14, The elastomer layer 18 formed on the outer surface of the primer layer 16 and It is equipped with. 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 is conductive. Examples of materials for the shaft 12 include: (a) Metals such as stainless steel, aluminum alloy, copper alloy, magnesium alloy, (b) A composite material in which a conductive agent is dispersed in a matrix made of resin, (c) Composite material in which a conductive coating is formed on the surface of a resin These are some examples. In particular, a metal shaft is preferred for shaft 12. This is because metal shafts have higher conductivity and strength, and are less expensive, 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 depending on the purpose. The shaft 12 may be a solid shaft or a hollow shaft.

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

[0021] [1.2.1. Materials] [A. Foamed resin] In the present invention, the type of foamed resin is not particularly limited. Examples of foamed resin materials 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), and ethylene-vinyl acetate copolymer (EVA).

[0022] Among these, foamed polyurethane is preferred for the foamed resin. The OA roller 10 repeatedly comes into contact with and separates from an object at high speed during use, and deforms and recovers accordingly. If the surface recovery force of the OA roller 10 is weak, the OA roller 10 will come into contact with the next object while the surface remains indented, which may cause horizontal white streaks or color unevenness in the image. Foamed polyurethane has the advantage of being less prone to such white streaks and color unevenness because it has a greater recovery force than other materials. Foamed polyurethane also has the advantage of being highly abrasion resistant.

[0023] In this invention, the density of the foamed resin is not particularly limited, and an optimal value can be selected depending on the purpose. Generally, if the density is too low, it may be difficult to retain the liquid primer material on the surface of the substrate layer 14 when the liquid primer material is applied to the surface of the substrate layer 14. Therefore, the density is 35 kg / m³. 3 The above is preferable. On the other hand, if the density becomes too high, it may become difficult to manufacture the foamed resin. Therefore, the density should be 800 kg / m³. 3 The following is preferable. The density is more preferably 720 kg / m³. 3 The following applies: In this invention, "density of the base layer 14" refers to the density of the foamed resin containing the pigment and, if necessary, the ion conductive agent A.

[0024] The bubbles in the foamed resin are preferably closed-cell bubbles. This is because, when forming a primer layer 16 on the surface of the base layer 14, the raw materials of the primer layer 16 do not easily penetrate into the interior of the foamed resin. Furthermore, it is preferable that the surface of the base layer 14 has minimal irregularities. This is because the less irregularity the surface of the base layer 14 has, the easier it becomes to fill the depressions on the surface of the base layer 14 with the primer.

[0025] [B. Pigments] The base layer 14 contains pigment dispersed within the foamed resin. "The pigment is dispersed within the foamed resin" means, (a) The pigment is filled in the gaps between the polymer chains that make up the foamed resin, and / or (b) The foamed resin has pigments filled in the air bubbles. It refers to.

[0026] The pigment is added primarily to color the substrate layer 14 to a desired color, to make discoloration (yellowing) of the foamed resin less noticeable, and to control the conductivity of the substrate layer 14. In the present invention, the pigment consists of a material that absorbs ultraviolet light. The pigment may be a material with high conductivity, or it may be a material with low conductivity. Examples of pigments 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, These are some examples. In particular, carbon is preferred as the pigment. This is because the substrate layer 14 is colored black, making yellowing less noticeable, and the conductivity of the substrate layer 14 can be controlled relatively easily.

[0027] Carbon includes various materials with different shapes and conductivity. Examples of carbon include: (a) Carbon blacks with a large structure, such as acetylene black and Ketjen black, that have a large function of enhancing the conductivity of the substrate layer 14 (hereinafter, these will be collectively referred to as "conductive carbon"), (b) Carbon black with a small structure, such as furnace black, which has little function in enhancing the conductivity of the substrate layer 14 (hereinafter these will be collectively referred to as "pigment carbon"), (c) Graphite powder, (d) Carbon fiber These are some examples.

[0028] [C. Ionic conductive agent A] When the OA roller 10 is used as a transfer roller, for example, the base layer 14, primer layer 16, and elastomer layer 18 must have a predetermined conductivity. If the conductivity required for the OA roller 10 can be obtained solely by adding pigment to the base layer 14 and optimizing the primer layer 16 and elastomer layer 18 (including optimizing the thickness of each layer), then the ionic conductive agent A is not necessarily required. On the other hand, if the conductivity required for the OA roller 10 cannot be obtained solely by adding pigment to the base layer 14 and optimizing the primer layer 16 and elastomer layer 18, then it is preferable to add the ionic conductive agent A to the base layer 14.

[0029] In the present invention, the material of the ion conductive agent A added to the substrate layer 14 is not particularly limited. For example, the ion conductive agent A is: (a) Ammonium salts such as perchlorates, chlorates, hydrochlorides, bromates, iodates, borofluorides, sulfates, ethyl sulfates, carboxylates, sulfonates, etc., including tetraethylammonium, tetrabutylammonium, dodecyltrimethylammonium (e.g., lauryltrimethylammonium), hexadecyltrimethylammonium, octadecyltrimethylammonium (e.g., stearyltrimethylammonium), benzyltrimethylammonium, and modified fatty acid dimethylethylammonium. (b) Perchlorates, chlorates, hydrochlorides, bromates, iodates, borofluorides, trifluoromethyl sulfates, sulfonates of alkali metals and alkaline earth metals such as lithium, sodium, potassium, calcium, and magnesium, (c) The cation species include imidazolium ions, pyridinium ions, pyrrolidinium ions, piperidinium ions, and phosphonium ions. Salts containing anionic species such as halogen ions (chlorine, bromine, iodine, etc.), borate ions (tetrafluoroborate ions, etc.), phosphate ions (hexafluorophosphate ions, etc.), and sulfate ions (bis(trifluoromethanesulfonyl)imide ions, etc.) These are some examples.

[0030] [1.2.2. Content] The pigment content in the base layer 14 is not particularly limited, and the optimal content can be selected depending on the type of pigment, the presence or absence of ion conductive agent A, and the application of the OA roller 10. Similarly, if the base layer 14 contains an ionic conductive agent A, the content of the ionic conductive agent A is not particularly limited, and an optimal content can be selected depending on the type of pigment, the application of the OA roller 10, etc.

[0031] Generally, if the pigment content is too low, yellowing may become more noticeable, or the desired conductivity may not be achieved. Therefore, a pigment content of 0.4 mass% or more is preferable. On the other hand, if the pigment content is excessive, the viscosity of the raw material containing it may increase excessively, making it difficult to manufacture the base layer 14. Also, if the pigment content is excessive, the base layer 14 may become brittle. Therefore, the pigment content is preferably 19.6 mass% or less.

[0032] The content of ion conductive agent A is not particularly limited, and the optimal content can be selected according to the purpose. Generally, the higher the content of ion conductive agent A, the higher the conductivity that can be obtained. On the other hand, if the content of ion conductive agent A is excessive, the mechanical properties of the substrate layer 14 may decrease. Specifically, the content of ion conductive agent A is preferably between 0.01 mass% and 10.0 mass%.

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

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

[0035] [1.3.1. Materials] In the present invention, the primer layer 16 includes a non-UV curable elastomer. A "non-UV curable elastomer" refers to an elastomer that can be cured without irradiation with ultraviolet light.

[0036] Examples of non-UV curing elastomers include, (a) Thermosetting and solvent-volatile elastomers such as polyurethane elastomers, acrylic elastomers, and styrene elastomers, (b) Primer paints such as acrylic, ethylene vinyl acetate, urethane, and epoxy. These are some examples. The material for the primer layer 16 is preferably a polyurethane elastomer. This is because the glass transition temperature and temperature dependence of the viscoelasticity of the polyurethane elastomer may be close to those of the materials used for the base layer 14 and the elastomer layer 18.

[0037] The material of the primer layer 16 may consist solely of a non-UV-curable elastomer, or it may contain other components, as long as it prevents contact between the uncured elastomer layer 18 and the substrate layer 14. Other components may include, for example, conductive materials such as metal powders or ionic conductive agents that do not absorb ultraviolet light.

[0038] However, the primer layer 16 must not contain pigments that absorb ultraviolet light. This is because if the primer layer 16 contains pigments that absorb ultraviolet light, it becomes difficult to cure the raw materials of the elastomer layer 18 with ultraviolet light. The primer layer 16 may be made of a foamed material or a non-foamed material. However, if the primer layer 16 is made of a foamed material, the raw materials for the elastomer layer 18 may seep into the bubbles of the primer layer 16, and when the raw materials for the elastomer layer 18 come into contact with the base layer 14, the curing of the raw materials may be insufficient. To suppress such seepage of raw materials, it is preferable that the primer layer 16 be made of a non-foamed material.

[0039] [1.3.2. Thickness] As described later, the primer layer 16 is formed by applying the raw materials for the primer layer 16 to the surface of the base layer 14 and curing the coating film. In this case, since the base layer 14 contains air bubbles, some of the raw materials for the primer layer 16 may seep into the air bubbles of the base layer 14, and the raw materials may harden within the air bubbles. In the present invention, "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 in which the raw materials of the primer layer 16 have permeated into the air bubbles of the base material layer 14 and hardened.

[0040] The thickness of the primer layer 16 affects the performance and cost of the OA roller 10. If 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 greater 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 becomes too thick, the curing process of the primer layer 16 will take a long time, which may increase manufacturing costs. 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 surface of the primer layer 16. The elastomer layer 18 is formed to suppress the deficiency of electrostatic force caused by the irregularities of the substrate layer 14. In the present invention, the elastomer layer 18 includes an ultraviolet-curable elastomer. The elastomer layer 18 may consist only of an ultraviolet-curable elastomer, or it may further contain an ionic conductive agent B in addition to the ultraviolet-curable elastomer.

[0042] [1.4.1. Materials] [A. UV-curing elastomer] The elastomer layer 18 includes an ultraviolet-curable elastomer. The ultraviolet-curable elastomer is not particularly limited, as long as it can be cured using ultraviolet light. Some ultraviolet-curable elastomers exhibit relatively high conductivity, while others exhibit relatively low conductivity. Either type may be used for the elastomer layer 18.

[0043] The elastomer layer 18 is particularly, A raw material comprising a urethane prepolymer having an allyl group, a vinyl ether group, or an acrylate group as terminal functional groups, and a polythiol having a thiol group, is applied to the surface of the primer layer. The coating film made of the aforementioned raw materials is irradiated with ultraviolet light to induce an enthiol reaction. It is preferable that the product contains an elastomer obtained by this process. To effectively carry out the reaction between allyl groups and thiol groups, it is preferable to add a photopolymerization initiator to the raw materials. The elastomer layer 18 obtained by this method has advantages over non-UV curable elastomers, such as lower cost of curing equipment, the ability to miniaturize curing equipment, and reduced curing time.

[0044] Other materials for the elastomer layer 18 include, for example, a composition containing a (meth)acrylate oligomer and an ultraviolet polymerization initiator.

[0045] [B. Ion Conducting Material B] As described above, when the OA roller 10 is applied to, for example, a transfer roller, the base layer 14, primer layer 16, and elastomer layer 18 must have a predetermined conductivity. If the conductivity required for the OA roller 10 can be obtained solely by optimizing the UV-curable elastomer material constituting the elastomer layer 18, and by optimizing the base layer 14 and primer layer 16 (including optimizing the thickness of each layer), then the ionic conductive agent B is not necessarily required. On the other hand, if the conductivity required for the OA roller 10 cannot be obtained solely by optimizing the UV-curable elastomer material, and by optimizing the base layer 14 and primer layer 16, then it is preferable to add the ionic 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. If the base layer 14 contains an ion conductive material A, the ion conductive material B may be the same material as the ion conductive material A, or it may be a different material. Other aspects of the ion conductive material B are the same as those of the ion conductive material A, so a detailed explanation is omitted.

[0047] [1.4.2. Content] When the elastomer layer 18 contains ionic conductive agent B, the amount of ionic conductive agent B is not particularly limited, and the optimal amount can be selected depending on the type of UV-curable elastomer, the application of the OA roller 10, etc.

[0048] Generally, if the content of ionic conductive agent B is too low, the conductivity may decrease. Therefore, the content of ionic conductive agent B is preferably 0.05 mass% or more. On the other hand, if the content of ionic conductive agent B is excessive, the mechanical properties of the elastomer layer 18 may deteriorate. Therefore, the content of 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 the optimal thickness can be selected according to the purpose. Generally, if 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. Therefore, the thickness of the elastomer layer 18 is preferably 0.5 mm or more. On the other hand, making the elastomer layer 18 thicker than necessary does not make a difference in effect and is not beneficial. Therefore, the thickness of the elastomer layer 18 is preferably 5.0 mm or less. More preferably, the thickness is 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 providing stain resistance to the OA roller 10. The material for the OC layer is not particularly limited, and the most suitable material can be used depending on the purpose. Examples of OC layer materials include water-based urethane paints. Furthermore, the thickness of the OC layer is not particularly limited, and the 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 OA Rollers] "Volume resistivity" refers to the value calculated from the current flowing between the outermost surfaces of the shaft 12-OA roller 10 when current is passed between the outermost surfaces of the shaft 12-OA roller 10 under conditions of temperature: 22℃±3℃, 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 depending on the purpose. Specifically, the volume resistivity of the OA roller 10 is preferably between 3 (logΩ) and 10 (logΩ).

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

[0054] [2. Method for manufacturing rollers for office automation equipment] The OA roller 10 according to the present invention is (a) A base material layer 14 is formed on the outer surface of the shaft 12. (b) A primer layer 16 is formed on the outer surface of the base layer 14. (c) Form an elastomer layer 18 on the outer surface of the primer layer 16. (d) If necessary, an OC layer is further formed on the outer surface of the elastomer layer 18. It can be manufactured by doing so.

[0055] [2.1. 1st step] First, a base material layer 14 is formed on the outer surface of the shaft 12 (first step). In the present invention, the method for forming the base material layer 14 is not particularly limited. For example, the method for forming the base layer 14 is: (a) A method of manufacturing a cylindrical foam containing foamed resin, inserting a shaft into a through hole in the foam, and bonding the foam and the shaft together. (b) A method in which a shaft is erected in the center of a cylindrical mold, and foaming resin raw material is poured into the gap between the inner wall surface of the mold and the shaft, and the raw material is foamed and hardened inside the mold. These are some examples.

[0056] Furthermore, a method for producing a foam containing a pigment and / or ionic conductive agent A is, for example, (a) A method of adding a pigment and / or an ionic conductive agent A to the raw material of a foamed resin in advance, and then foaming and curing the raw material, (b) A method of preparing a foam using a foam resin raw material that does not contain pigment and ionic conductive agent A, immersing the foam in a dispersion containing the pigment and / or ionic conductive agent A, removing the foam from the dispersion, and drying it. These are some examples.

[0057] The composition of the raw materials used to produce foamed resin is not particularly limited, and the optimal composition can be selected depending on the type of foamed resin. For example, when the foamed resin consists of foamed polyurethane, it is preferable to use a raw material that is a mixture of polyol, isocyanate, foam stabilizer, resinification catalyst, pigment, and ionic conductive agent A in predetermined proportions. By mixing such raw materials in a mixer while blowing in an inert gas, mechanical foaming is performed, and then curing, a foam made of foamed polyurethane containing a predetermined amount of pigment and ionic conductive agent A can be produced.

[0058] Alternatively, a raw material containing polyol, isocyanate, foam stabilizer, resin catalyst, foaming agent, foaming catalyst, pigment, and ionic conductive agent A in predetermined proportions 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 pigment and / or ionic conductive agent A can be produced.

[0059] [2.2. 2nd process] Next, a primer layer 16 is formed on the outer surface of the base layer 14. In the present invention, the method for forming the primer layer 16 is not particularly limited. For example, the method for forming the primer layer 16 is: (a) A method of dissolving a solvent-soluble elastomer in a solvent such as water or an organic solvent, applying the solution to the surface of the substrate layer 14, and drying the coating film. (b) A method in which a low-viscosity liquid elastomer is applied to the surface of the substrate layer 14 and the coating film is cured by heat, moisture, etc. (addition curing, condensation curing) These are some examples.

[0060] [2.3. Third step] Next, an elastomer layer 18 is formed on the outer surface of the primer layer 16. The elastomer layer 18 is, specifically, (a) The raw material for the UV-curable elastomer is applied to the surface of the primer layer 18. (b) Irradiate the coating with ultraviolet light to cure it. It can be manufactured by doing so.

[0061] The composition of the raw materials for forming the elastomer layer 18 is not particularly limited, and it is preferable to select the optimal composition depending on the type of UV-curable elastomer. For example, if the elastomer layer 18 includes an elastomer obtained by photopolymerizing a urethane prepolymer and a polythiol, (a) Urethane prepolymers having an allyl group, a vinyl ether group, or an acrylate group as terminal functional groups, (b) Polythiols having thiol groups, (c) Photopolymerization initiator, (d) Ionic conductive agent B It is preferable to blend them in a predetermined ratio. When such raw materials are applied to the surface of the primer layer 16 and the coating film is irradiated with ultraviolet light to cure it, an 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 polythiols include esters of mercaptocarboxylic acids and polyhydric alcohols, fatty acid polythiols, and aromatic polythiols. Examples of photopolymerization initiators include acetophenone compounds, benzophenone compounds, and thioxanthone compounds. When these raw materials are irradiated with ultraviolet light, the urethane prepolymer and polythiol undergo an enthiol reaction, forming an elastomer. After hardening, the surface of the elastomer layer is polished using a cylindrical polishing machine to refine its shape.

[0063] [4. 4th 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 the most suitable method can be selected depending on the purpose.

[0064] [3. Effect] Figure 2 shows a schematic diagram of a conventional method for manufacturing an office automation roller. First, as shown in Figure 2(A), a base layer 14 is formed on the outer surface of the shaft 12. The base layer 14 consists of a foamed resin 14a in which a pigment 14b that absorbs ultraviolet light is dispersed. Next, as shown in Figure 2(B), the raw material 18a of the UV-curable elastomer is directly applied to the outer surface of the base layer 14. Since the base layer 14 contains foamed resin 14a, a portion of the raw material 18a permeates into the base layer 14.

[0065] When ultraviolet light is irradiated onto the raw material 18a in this state, the raw material 18a on top of the base layer 14 hardens due to the ultraviolet light and becomes the elastomer layer 18. However, hardening defects occur in the raw material 18a near the interface between the base layer 14 and the elastomer layer 18. This is thought to be because, near the interface between the base layer 14 and the elastomer layer 18, the pigment 14b absorbs or blocks the ultraviolet light, preventing a sufficient amount of ultraviolet light from being irradiated onto the raw material 18a near the interface.

[0066] Figure 3 shows a schematic diagram of the manufacturing method of an OA roller according to the present invention. First, as shown in Figure 3(A), a base layer 14 is formed on the outer surface of the shaft 12. The base layer 14 consists of a foamed resin 14a in which a pigment 14b that absorbs ultraviolet light is dispersed. Next, as shown in Figure 3(B), the raw material 16a for the primer layer is applied to the outer surface of the base layer 14. Since the base layer 14 contains foamed resin 14b, a portion of the raw material 16a permeates into the base layer 14. After applying the raw material 16a, the solvent is evaporated, or heat or moisture is applied, causing the raw material 16a to harden and the primer layer 16 to be formed.

[0067] Furthermore, as shown in Figure 3(C), the raw material 18a of the UV-curable elastomer is applied to the outer surface of the primer layer 16. If the primer layer 16 is substantially bubble-free, or if the thickness of the primer layer 16 is sufficiently thick, the raw material 18a will not penetrate into the primer layer 16 and the substrate layer 14. When the raw material 18a is irradiated with ultraviolet light from this state, the raw material 18a hardens due to the ultraviolet light and becomes an elastomer layer 18.

[0068] In the OA roller 10 according to the present invention, when an elastomer layer 18 containing an ultraviolet-curable elastomer is formed on the outer surface of a base layer 14 containing an ultraviolet-absorbing pigment 14b and a foamed resin 14a, a primer layer 16 is interposed between the base layer 14 and the elastomer layer 18. As a result, curing defects of the raw material 18a of the ultraviolet-curable elastomer are suppressed. This is thought to be because forming the primer layer 16 on the outer surface of the base layer 14 suppresses the absorption or shielding of ultraviolet rays by the pigment 14b near the interface between the primer layer 16 and the elastomer layer 18. Furthermore, the curing time can be shortened compared to when the entire elastomer layer 18 and primer layer 16 are made using non-ultraviolet-curable elastomers such as thermosetting elastomers or moisture-curing elastomers. [Examples]

[0069] (Examples 1-6, Comparative Examples 1-7) [1. Sample Preparation] [1.1. Examples 1-6, Comparative Examples 1-6] [1.1.1. Preparation of the base layer] First, a foam slab to serve as the base layer was prepared. Next, the foam was cut into strips the size of one roll (each strip having a hole for inserting a shaft). The shaft, coated with adhesive, was inserted into the hole in the strip, and the shaft and strip were bonded together. Furthermore, the outer surface of the strip was polished using a cylindrical polishing machine to obtain a cylindrical base layer. Foamed polyurethane was used for the foam base layer. The details of the foam preparation method are as follows.

[0070] [A. ENDUR (Mechanically Foamed Polyurethane Foam)] A polyol, isocyanate, foam stabilizer, and resinification catalyst were mixed in predetermined proportions. To this raw material mixture, a predetermined amount of pigment and / or ion conductor A was added as needed. Tetraalkylammonium perchlorate was used as the ion conductor A. The raw material mixture was foamed and cured by mixing it in a mixer while blowing in an inert gas, thereby obtaining a foam (equivalent to ENDUR, manufactured by Inoac Corporation). The density of the obtained foamed polyurethane was 12-50 pcf (192 kg / m³). 3 ~800kg / m 3 The Asker C hardness was 10-50°. The thickness of the substrate layer after cylindrical polishing was 3.5-5.5 mm.

[0071] [B. UEM-55 (Slab Urethane Foam A)] A polyol, isocyanate, foam stabilizer, water (foaming agent), resinification catalyst, and foaming catalyst were mixed in predetermined proportions. To this mixture, a predetermined amount of ion conductive material A was added as needed. The raw material mixture was poured into a mold and foamed to obtain a foam (equivalent to UEM-55, manufactured by Inoac Corporation). Tetraalkylammonium perchlorate was used as the ion conductive material A. Next, pigment was added to some of the foams by impregnation. Specifically, the foam (slab) was made into a sheet, cut, and then holes were made in the sheet for inserting shafts. The sheet was then immersed in a dispersion of pigment in water. After a predetermined time, the sheet was removed from the dispersion and dried. The density of the resulting foamed polyurethane was 50-75 kg / m³. 3 The FP hardness was 40-80°. Furthermore, the thickness of the substrate layer after cylindrical polishing was 3.5-5.5 mm.

[0072] [C. EP-70 (Slab Urethane Foam B)] A block of EP-70 manufactured by Inoac Corporation was sliced ​​into 40mm thick strips. Next, the resulting sheets were cut into strips measuring 40mm in width and 370mm in length. Furthermore, a φ13mm hole was formed on one end face (a 40mm x 40mm surface) of the resulting strip (40mm x 40mm x 370mm), extending from the center of the other end face. Next, the perforated strips were immersed in a dispersion of pigment and a binder (a component that adheres the pigment to urethane) in water, allowing the dispersion to permeate the air bubbles in the strips. After that, the strips were removed from the dispersion and dried at a temperature of 100°C or higher. Next, a separate metal shaft was coated with hot melt adhesive and inserted into the hole in the strip. Then, the strip with the shaft inserted was heated to a temperature above the melting point of the hot melt adhesive. After heating for a predetermined time, the strip with the shaft inserted was cooled to near room temperature. Furthermore, the outer surface of the strips 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 the Primer Layer] In Examples 1 to 6, a primer layer was formed on the outer surface of the substrate layer. A solvent-volatile urethane-based primer (Nipporan® 5230, manufactured by Tosoh Corporation) was used as the raw material for the primer layer. A predetermined amount of the urethane-based primer was applied to the outer surface of the substrate layer and dried. The thickness of the resulting primer layer was 0.2 to 0.8 mm.

[0074] [1.1.3. Fabrication of the elastomer layer] Next, an elastomer layer was formed on the outer surface of the primer layer (Examples 1-6) or the outer surface of the substrate layer (Comparative Examples 1-6). A UV-curable polyurethane elastomer was used for the elastomer layer. Details of the method for preparing the elastomer layer are as follows.

[0075] [A. SC-22 (UV-curing polyurethane elastomer A)] A polyurethane prepolymer having methacrylic groups as terminal functional groups, ionic conductive agent B, polythiol, and a photopolymerization initiator were mixed in a predetermined ratio. The content of ionic conductive agent B was equivalent to 3.0 mass% of the total mass of the cured elastomer layer. The raw material was applied to the surface of the primer layer or the substrate layer using a doctor blade while rotating a roller, and cured by irradiation with ultraviolet light. After curing, the outer surface was polished with a cylindrical polishing machine to obtain an elastomer layer with a thickness of 2 mm.

[0076] The polyurethane prepolymer used was a prepolymer synthesized from AN-002 manufactured by Mitsui Chemicals, Inc. and T-80 manufactured by Tosoh Corporation. For the ionic conductive agent B, we used Elegan LD-204 manufactured by NOF Corporation. For the polythiol, we used TMMP manufactured by SC Organic Chemicals Co., Ltd. OMNIRAD2959 from IGM RESINS BV was used as the photopolymerization initiator.

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

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

[0079] [1.1.4. Fabrication of the OC layer] After forming the elastomer layer, an OC layer (surface coating) was formed on the outer surface of the elastomer layer. The OC layer was formed by applying BONDERITE® S-FN T-862A AN, manufactured by Henkel Japan, to a film thickness of 5 to 40 μm and then 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 in predetermined ratios to obtain a raw material composition. A cylindrical molded body (hereinafter also referred to as the "base layer precursor") was attached to the surface of the shaft by extrusion molding of the obtained raw material composition. Separately, acrylonitrile-butadiene rubber (NBR), a vulcanization aid, a mold release agent, a vulcanizing agent, and a vulcanization accelerator were mixed in predetermined ratios to obtain a raw material composition. The raw material composition was extruded to obtain a cylindrical molded body (hereinafter also referred to as "elastomer layer precursor").

[0081] A cylindrical elastomer layer precursor was placed inside a cylindrical roll molding die. Next, a shaft with a base layer precursor formed on it was inserted into the elastomer layer precursor. In this state, the elastomer layer precursor and base layer precursor were heated at 160°C for 40 minutes to crosslink and foam the raw material composition. After cooling, the base material layer and the shaft with the elastomer layer were removed from the mold. Next, the outer surface of the elastomer layer was polished using a cylindrical polishing machine 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 the base layer was formed (hereinafter also referred to as "volume resistivity of the base layer"), the volume resistivity of the roller after the elastomer layer was formed (hereinafter also referred to as "volume resistivity of the elastomer layer"), and the volume resistivity after an OC layer (surface coating) was further formed on the surface of the elastomer layer (hereinafter also referred to as "volume resistivity of the OC layer") were measured. The volume resistivity of the roller after the primer layer was formed was not measured. Furthermore, for the "volume resistivity of the base layer" in Comparative Example 7, the measurement was taken using a sample in which the base layer and elastomer layer were integrally formed and the elastomer layer was removed by cylindrical polishing. The measurement conditions were: temperature: 22℃±3℃, relative humidity: 55%±5%, voltage: 100V.

[0083] [2.2. Degree of hardening and adhesion of the elastomer layer] The degree of hardening and adhesion of the elastomer layer were visually evaluated.

[0084] [3. Results] The results are shown in Tables 1 and 2. The history of each sample is also shown in Tables 1 and 2. Regarding "imparting conductivity to the substrate," "○" indicates that it was possible to impart conductivity to the substrate layer using either the pigment or the ionic conductive agent A, while "△" indicates that it was not possible to impart conductivity to the substrate layer using a conductive agent that causes the substrate layer to turn black (i.e., carbon).

[0085] Regarding "curing of the elastomer layer," "○" indicates that the elastomer layer has cured sufficiently. "△" indicates that the elastomer layer has not cured sufficiently at the interface with the substrate layer. Regarding the "adhesion of the elastomer layer," "○" indicates that the elastomer layer is sufficiently adhered. "×" indicates that delamination has occurred between the substrate layer and the elastomer layer.

[0086] Regarding the "elastomer layer molding time," "○" indicates that curing was possible in 5 to 600 seconds, and "×" indicates that curing took more than 600 seconds. Regarding the "conductive performance of the roller," "○" indicates that the volume resistivity of the roller can be adjusted by the volume resistivity of the base layer and the volume resistivity of the elastomer layer, and that the adjustment range of the roller's volume resistivity is wide. "△" indicates that the adjustment range of the volume resistivity is narrow. From Tables 1 and 2, the following can be seen.

[0087] (1) In Comparative Examples 3 to 6, the elastomer layer did not harden sufficiently. This is thought to be because the carbon contained in the substrate layer absorbed or blocked ultraviolet light, preventing the raw materials from hardening sufficiently near the interface between the substrate layer and the elastomer layer. (2) In Comparative Examples 1 and 2, the elastomer layer hardened sufficiently. However, because the base layer did not contain pigment (carbon), it was difficult to adjust the volume resistivity of the roller. (3) Comparative Example 7 had the base layer and the elastomer layer formed integrally, but crosslinking and foaming (i.e., formation of the elastomer layer) took a long time of 40 minutes. Furthermore, the restoring force of the roller obtained in Comparative Example 7 was inferior to that of a roller using urethane-based materials for both the base layer and the elastomer layer.

[0088] (4) In all of Examples 1 to 6, the elastomer layer was sufficiently cured. Furthermore, by controlling the type and amount of pigment and ionic conductive agent A added to the base layer, the type and amount of ionic conductive agent B added to the elastomer layer, and the thickness of each layer, the volume resistivity of the roller could be adjusted to the desired value. (5) By interposing a primer layer between the substrate layer and the UV-curable elastomer layer, it was possible to bond the substrate layer and the UV-curable elastomer layer regardless of the color of the substrate layer.

[0089] [Table 1]

[0090] [Table 2]

[0091] Although embodiments of the present invention have been described in detail above, the present invention is not limited in any way to the above embodiments, and various modifications are possible without departing from the spirit of the present invention. [Industrial applicability]

[0092] The OA roller according to the present invention can be used as a transfer roller, charging roller, toner supply roller, developing roller, fixing roller, paper feed roller, paper discharge roller, etc. [Explanation of Symbols]

[0093] 10 rolls for office automation 12 shafts 14 Base material layer 16. Primer layer 18 Elastomer layer

Claims

[Claim 1] A conductive shaft, A base material layer formed on the outer surface of the shaft, A primer layer formed on the outer surface of the substrate layer, The elastomer layer formed on the outer surface of the primer layer and Equipped with, The substrate layer comprises a foamed resin and a pigment that absorbs ultraviolet light, which is filled within the bubbles of the foamed resin. The aforementioned primer layer consists solely of a non-UV curable elastomer. The elastomer layer includes an ultraviolet-curable elastomer. OA roller.

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