Paper feed roll

Abstract

To provide a paper feed roll capable of suppressing occurrence of non-uniform adhesion of paper dust for each part on a surface of an elastic layer, exhibiting, even after long-time use, an excellent sheet-conveyance property, and avoiding sheet jamming, even though the elastic layer includes a first phase containing ethylene propylene diene rubber and a second phase containing at least one of isoprene rubber and natural rubber.SOLUTION: A paper feed roll 10 comprises: a shaft body 12; and an elastic layer 14 formed on an outer periphery of the shaft body 12. The elastic layer 14 contains a polymer and monoglyceride, and a content of the monoglyceride is 0.5-5 pts.mass with respect to 100 pts.mass of the polymer. The elastic layer 14 has: a first phase containing ethylene propylene diene rubber; and a second phase containing at least one of isoprene rubber and natural rubber.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a paper feed roll suitably used in electrophotographic devices such as copiers, printers, and facsimiles that employ an electrophotographic method.

Background Art

[0002] As a paper feed roll, one having an elastic body layer made of an elastic material such as a rubber crosslinked body on the outer peripheral surface of a shaft body such as a core metal is known. As the elastic material of the elastic body layer, a combination of ethylene propylene diene rubber and isoprene rubber or styrene butadiene rubber is known (Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the elastic material of the elastic body layer is composed of two or more polymer components, the elastic body layer is often composed of two or more phases with different polymer components. Since the polymer components are different, the amount of paper dust adhering differs for each phase. As a result, after long-term use, the difference in the friction coefficient for each phase becomes large, so the surface of the elastic body layer tends to have a non-uniform friction coefficient. If the friction coefficient on the surface of the elastic body layer is non-uniform, there is a problem that the paper cannot be conveyed straight and conveyance failure (paper jamming) occurs.

[0005] The problem to be solved by the present invention is to suppress uneven paper dust adhesion generation for each part of the surface of the elastic body layer even when the elastic body layer has a first phase containing ethylene propylene diene rubber and a second phase containing at least one of isoprene rubber and natural rubber, and to provide a paper feed roll that has excellent paper conveyance performance even after long-term use and can avoid paper jamming.

Means for Solving the Problems

[0006] The paper feed roll according to the present invention includes a shaft body and an elastic body layer formed on the outer peripheral surface of the shaft body. The elastic body layer has a first phase containing ethylene propylene diene rubber, a second phase containing one or more of isoprene rubber and natural rubber, and a monoglyceride obtained by reacting glycerin and fatty acid. The monoglyceride is 0.5 part by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the polymers of the first phase and the second phase.

[0007] Preferably, the monoglyceride is further a monoglyceride obtained by reacting glycerin and a fatty acid having 12 to 22 carbon atoms. Also preferably, the monoglyceride is a monoglyceride obtained by reacting glycerin and an unsaturated fatty acid. Further, preferably, within an arbitrary range of 2.5 μm × 2.5 μm square of the elastic body layer, the area ratio of the second phase is within the range of 30 to 70%. Also preferably, the monoglyceride of the elastic body layer is present in the first phase at a higher concentration than in the second phase.

Advantages of the Invention

[0008] According to the paper feed roll of the present invention, which includes a shaft body and an elastic body layer formed on the outer periphery of the shaft body, the elastic body layer has a first phase containing ethylene propylene diene rubber, a second phase containing one or more of isoprene rubber and natural rubber, and a monoglyceride obtained by reacting glycerin and fatty acid. The monoglyceride is 0.5 part by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the polymers of the first phase and the second phase. Thus, after long-term use, adhesion of paper dust to the surface of the elastic body layer can be suppressed. Therefore, the amount of paper dust adhesion does not vary depending on the site on the surface of the elastic body layer. Also, even if paper dust adheres to the surface of the elastic body layer, it peels off, so the friction coefficient is hardly changed. As a result, conveyance failure (paper jamming) of the paper after long-term use can be eliminated.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

DETAILED DESCRIPTION OF THE INVENTION

[0010] The paper feed roll according to the present invention will be described in detail. FIG. 1 is the schematic external view (a) of the paper feed roll according to an embodiment of the present invention and its sectional view taken along line A-A (b).

[0011] The paper feed roll 10 according to an embodiment of the present invention includes a shaft body 12 and an elastic body layer 14 formed on the outer peripheral surface of the shaft body 12. The elastic body layer 14 is a layer (base layer) serving as the base of the paper feed roll 10. The elastic body layer 14 is the layer that appears on the surface of the paper feed roll 10.

[0012] The shaft body 12 may be a solid body or a hollow body (cylindrical body) made of metal or resin. Examples of the metal material include iron, stainless steel, and aluminum. The elastic body layer 14 may be adhered to the shaft body 12 via an adhesive layer (primer layer). Conductive treatment may be performed on the adhesive, primer, etc. as necessary.

[0013] The elastic layer 14 contains a polymer and a monoglyceride, the content of the monoglyceride is 0.5 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the polymer, and the elastic body layer has a first phase containing ethylene propylene diene rubber and a second phase containing at least one of isoprene rubber and natural rubber.

[0014] In the elastomeric layer 14, the first phase containing ethylene propylene diene rubber is suitable for making the hardness of the elastomeric layer 14 within a desired range. The second phase containing one or more of isoprene rubber (IR) and natural rubber (NR) is a material having a higher coefficient of friction than the first phase containing ethylene propylene diene rubber, and is suitable for improving the coefficient of friction of the surface of the elastomeric layer 14. Monoglyceride obtained by reacting glycerin and fatty acid is suitable for suppressing paper powder adhesion to the elastomeric layer 14 (especially the first phase). The monoglyceride is 0.5 part by mass or more and 5 parts by mass or less based on 100 parts by mass of the polymers of the first phase and the second phase. By the monoglyceride bleeding out to the surface of the elastomeric layer 14, a thin film is formed between the surface of the elastomeric layer 14 and the adhered paper powder, and when the thin film is peeled off during the rotation of the paper feed roll 10, the paper powder adhered to the surface of the elastomeric layer 14 can be removed. This thin film is continuously formed by the bleeding out of the monoglyceride. Thereby, after long-term use, the adhesion of paper powder to the surface of the elastomeric layer 14 can be suppressed. Therefore, the amount of paper powder adhesion does not vary depending on the surface site of the elastomeric layer, and even if paper powder adheres to the surface of the elastomeric layer, the coefficient of friction is hardly changed. As a result, paper conveyance failure (paper jamming) after long-term use can be eliminated.

[0015] Ethylene propylene diene rubber is obtained by copolymerizing a non-conjugated diene as a third component with ethylene propylene rubber (EPM) which is a copolymer of ethylene and propylene. Ethylene propylene diene rubber has a structure in its molecular structure due to the ethylene propylene structure and non-conjugated diene. Examples of the non-conjugated diene of ethylene propylene diene rubber include ethylidene norbornene (ENB), 1,4-hexadiene (1,4-HD), dicyclopentadiene (DCPD), and the like.

[0016] The ethylene propylene diene rubber may be an oil-extended ethylene propylene diene rubber or a non-oil-extended ethylene propylene diene rubber. It may also contain both an oil-extended ethylene propylene diene rubber and a non-oil-extended ethylene propylene diene rubber. From the viewpoints such as being easily applied with a sufficient share during rubber kneading and processing and improving the dispersibility of the second phase with respect to the first phase, it is preferable to contain both an oil-extended ethylene propylene diene rubber and a non-oil-extended ethylene propylene diene rubber as the ethylene propylene diene rubber. From the viewpoint of excellent balance of physical properties, etc., the ratio of the oil-extended ethylene propylene diene rubber to the non-oil-extended ethylene propylene diene rubber is preferably in the range of 5:1 to 2:1 by mass ratio.

[0017] The oil for oil extension is not particularly limited as long as it is an oil compounded with ethylene propylene diene rubber, but paraffin oil, naphthenic oil, etc. are preferable.

[0018] When the area ratio of the second phase is in the range of 30% or more and 70% or less within an extremely narrow range of any 2.5 μm × 2.5 μm square on the surface of the elastic layer 14, both the first phase and the second phase are uniformly dispersed (finely dispersed) in the elastic layer 14. Therefore, after long-term use, it is difficult for a difference in the friction coefficient to occur depending on the site. As a result, it is preferable because paper conveyance failure (paper jamming) after long-term use can be more eliminated.

[0019] And the area ratio of the second phase is more preferably 35% or more and 65% or less, and even more preferably 40% or more and 60% or less. The area ratio of the first phase and the second phase can be measured by surface analysis using a scanning probe microscope (SPM).

[0020] "Arbitrary" means anywhere. The area ratios of the first phase and the second phase are those at any 2.5 μm × 2.5 μm square. Specifically, as shown in Fig. 2, any cross-section of the elastic body layer is observed, a range of any 40 × 40 μm in that cross-section is divided into 64 parts, 16 squares arranged in the diagonal direction with diagonal lines drawn are selected, and the area ratios of the first phase and the second phase within each 2.5 μm × 2.5 μm square are measured respectively. The value should be such that 14 or more (85% or more) of the 16 selected squares meet the requirement.

[0021] In order for both the first phase and the second phase to be uniformly dispersed (finely dispersed) at any 2.5 μm × 2.5 μm square, for example, methods such as using a dispersant to improve the dispersibility of both the first phase and the second phase, adjusting the blending ratio of the polymers of the first phase and the second phase, and kneading sufficiently to the desired degree of dispersion can be considered.

[0022] As the kneading conditions for the polymer of the first phase and the polymer of the second phase, it is preferably at a rotation speed of 30 rpm or more and a kneading time of 5 minutes or more. More preferably, it is at a rotation speed of 40 rpm or more and a kneading time of 10 minutes or more.

[0023] As the ratio of the polymer of the first phase to the polymer of the second phase, in terms of mass ratio, the range of the first phase: the second phase = 3:1 to 1:3 is preferred. More preferably, it is in the range of the first phase: the second phase = 2.5:1 to 1:2.5, and even more preferably in the range of the first phase: the second phase = 2:1 to 1:2.

[0024] Among the monoglycerides obtained by reacting glycerin with fatty acids, the number of carbon atoms of the fatty acid is 12 or more, preferably 17 or more from the perspective of thin film formation, and preferably 22 or less, more preferably 18 or less from the perspective of bleed-out. Also, as the fatty acid, linear fatty acids are preferred. Furthermore, both saturated and unsaturated fatty acids can be used, but unsaturated fatty acids are preferred because they inhibit crystallization, increase molecular mobility, and enhance the effect of thin film formation due to bleed-out.

[0025] A monoglyceride obtained by reacting glycerin with a fatty acid is a compound in which one molecule of fatty acid is ester-bonded to one molecule of glycerin. This is because diglycerides, in which two molecules of fatty acid are ester-bonded to one molecule of glycerin, and triglycerides, in which three molecules of fatty acid are ester-bonded to one molecule of glycerin, are less likely to bleed out.

[0026] Examples of fatty acids include those derived from natural oils and fats and synthetic ones. Examples of natural ones include those derived from natural oils and fats such as palm oil, beef tallow, rapeseed oil, rice bran oil, and fish oil. Examples of synthetic fatty acids include higher fatty acids having 5 to 36 carbon atoms. Specifically, saturated fatty acids such as caprylic acid, pelargonic acid, capric acid, undecanoic acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, margaric acid, stearic acid, nonadecylic acid, arachidic acid, and their branched fatty acids, and unsaturated fatty acids such as oleic acid, erucic acid, linoleic acid, linolenic acid, elaidic acid, sterolic acid, ricinoleic acid, ricinelaidic acid, arachidonic acid, punicic acid, myristoleic acid, palmitoleic acid, and their branched fatty acids. Among them, unsaturated fatty acids such as oleic acid, erucic acid, linoleic acid, linolenic acid, arachidonic acid, punicic acid, myristoleic acid, and palmitoleic acid are preferred, and oleic acid is particularly preferred, in terms of excellent repellency, flexibility, and fluidity.

[0027] The content of monoglyceride is 0.5 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the polymers in the first phase and the second phase. If the content of monoglyceride is less than 0.5 parts by mass, after long-term use, a thin film cannot be formed on the surface of the elastomeric layer 14, and the attached paper dust cannot be peeled off. Therefore, the decrease in the friction coefficient cannot be suppressed, resulting in a difference in the friction coefficient depending on the site on the surface of the elastomeric layer, and the paper conveyance failure (paper jamming) after long-term use cannot be eliminated. The content of monoglyceride is more preferably 1 part by mass or more. Even more preferably, it is 2 parts by mass or more. If the content of monoglyceride is more than 5 parts by mass, the friction coefficient on the surface of the elastomeric layer decreases due to the bleed-out of monoglyceride, and the paper conveyance property deteriorates. More preferably, it is 5 parts by mass or less. Even more preferably, it is 4 parts by mass or less.

[0028] Monoglyceride preferably exists in the first phase at a higher concentration than in the second phase. Since the first phase has lower paper dust adhesion resistance than the second phase and paper dust adhesion is likely to occur, by having monoglyceride present at a high concentration, an increase in the surface hardness of the elastomeric layer 14 can be suppressed, and the occurrence of paper dust adhesion can be effectively suppressed.

[0029] In order for monoglyceride to exist in the first phase at a higher concentration than in the second phase, for example, a method such as mixing monoglyceride obtained by previously reacting the polymer of the first phase with glycerin and fatty acid, and then mixing it with the polymer of the second phase can be considered.

[0030] The elastic layer 14 may further contain a dispersant. Examples of the dispersant include polymers having a partial structure of ethylene propylene diene rubber and a partial structure of either isoprene rubber or natural rubber, modified natural rubber, modified isoprene rubber, etc. Examples of the modified natural rubber include epoxidized natural rubber, chlorinated natural rubber, nitrided natural rubber (acrylonitrile nitrided natural rubber), etc. Examples of the modified isoprene rubber include epoxidized isoprene rubber, chlorinated isoprene rubber, nitrided isoprene rubber (acrylonitrile nitrided isoprene rubber), maleic acid modified isoprene rubber, (meth)acrylic acid modified isoprene rubber, etc. The elastic layer 14 preferably contains, as the dispersant, a polymer having a partial structure of ethylene propylene diene rubber and a partial structure of either isoprene rubber or natural rubber. Examples of the partial structure of ethylene propylene diene rubber include an ethylene propylene structure, a structure resulting from a diene, etc. The ethylene propylene structure is particularly preferred as the partial structure of ethylene propylene diene rubber. Examples of the partial structure of isoprene rubber or natural rubber include an isoprene structure. The dispersant preferably has a double bond from the viewpoint of being easily fixed by crosslinking, etc.

[0031] From the viewpoint of excellent dispersion effects on the first phase and the second phase, etc., the content of the dispersant is preferably 1.0 part by mass or more with respect to 100 parts by mass of the polymers of the first phase and the second phase. More preferably, it is 1.5 parts by mass or more, and still more preferably, it is 2.0 parts by mass or more. Also, from the viewpoint of easily maintaining the physical properties of the first phase and the second phase, etc., the content is preferably 10 parts by mass or less with respect to 100 parts by mass of the polymers of the first phase and the second phase. More preferably, it is 7.0 parts by mass or less, and still more preferably, it is 5.0 parts by mass or less.

[0032] The elastic layer 14 preferably further contains a hydrocarbon-based oil. Thereby, the dispersion effect between the first phase and the second phase can be easily obtained. Examples of the hydrocarbon-based oil include paraffin oil. From the viewpoint of improving the dispersibility between the first phase and the second phase, the content of the hydrocarbon-based oil is preferably 10 parts by mass or more with respect to 100 parts by mass of the polymers of the first phase and the second phase. More preferably, it is 15 parts by mass or more, and still more preferably 20 parts by mass or more. Further, from the viewpoint of suppressing the bleed-out of the hydrocarbon-based oil, the content is preferably 50 parts by mass or less with respect to 100 parts by mass of the polymers of the first phase and the second phase. More preferably, it is 45 parts by mass or less, and still more preferably 40 parts by mass or less.

[0033] From the viewpoint of ensuring a paper feeding function and the like, the elastic layer 14 is preferably configured such that the friction coefficient of the surface is in the range of 0.12 to 2.2. More preferably, it is in the range of 1.0 to 2.5. The surface of the elastic layer 14 refers to the outer peripheral surface of the elastic layer 14. The friction coefficient of the surface of the elastic layer 14 can be measured using a commercially available friction coefficient meter. The friction coefficient of the surface of the elastic layer 14 can be adjusted by the material composition of the elastic layer 14.

[0034] The elastic layer 14 is preferably configured such that the JIS-A hardness of the surface is in the range of 20 to 80 degrees. More preferably, it is in the range of 30 to 70 degrees. The surface of the elastic layer 14 refers to the outer peripheral surface of the elastic layer 12b. The surface hardness of the elastic layer 14 can be adjusted by the material composition of the elastic layer 14, the thickness of the elastic layer 14, and the like. When the JIS-A hardness of the surface of the elastic layer 14 is 20 degrees or more, paper powder adhesion can be easily suppressed. When the JIS-A hardness of the surface of the elastic layer 14 is 80 degrees or less, damage to the paper (such as paper chipping) can be easily suppressed, and deterioration of the image quality can be easily suppressed.

[0035] Surface irregularities such as embossing may be provided on the surface of the elastic layer 14. The surface irregularities of the elastic layer 14 can be formed by methods such as polishing and mold transfer.

[0036] The thickness of the elastic body layer 14 is not particularly limited, but it may be, for example, 1 to 10 mm.

[0037] The elastic body layer 14 can be manufactured, for example, as follows. First, the shaft body 12 is coaxially installed in the hollow part of a roll forming die, an uncrosslinked rubber composition is injected, heated and cured (crosslinked), and then demolded, or an elastic body layer 14 is formed on the outer periphery of the shaft body 12 by extruding the uncrosslinked rubber composition onto the surface of the shaft body 12.

[0038] The uncrosslinked rubber composition for forming the elastic body layer 14 may appropriately contain a crosslinking agent, a conductive agent, a foaming agent, a surfactant, a flame retardant, a coloring agent, a filler, a stabilizer, a mold release agent, etc. as required.

[0039] Examples of the crosslinking agent include sulfur crosslinking agents and peroxide crosslinking agents. These crosslinking agents may be used alone or in combination of two or more.

[0040] Examples of the sulfur crosslinking agent include conventionally known sulfur crosslinking agents such as powdered sulfur, precipitated sulfur, colloidal sulfur, surface-treated sulfur, insoluble sulfur, sulfur chloride, thiuram vulcanization accelerators, and polymer polysulfides.

[0041] Examples of the peroxide crosslinking agent include conventionally known peroxide crosslinking agents such as peroxyketal, dialkyl peroxide, peroxyester, ketone peroxide, peroxydicarbonate, diacyl peroxide, and hydroperoxide.

[0042] From the viewpoint of being difficult to bleed, etc., the compounding amount of the crosslinking agent is preferably in the range of 0.1 to 2 parts by mass, more preferably in the range of 0.3 to 1.8 parts by mass, and still more preferably in the range of 0.5 to 1.5 parts by mass with respect to 100 parts by mass of the uncrosslinked rubber.

[0043] According to the paper feed roll 10 configured as described above, the elastomeric layer 14 has a first phase containing ethylene propylene diene rubber, a second phase containing one or more of isoprene rubber and natural rubber, and a monoglyceride obtained by reacting glycerin and fatty acid. The monoglyceride is 0.5 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the polymers of the first phase and the second phase. After long-term use, the adhesion of paper dust to the surface of the elastomeric layer can be suppressed. Therefore, the amount of paper dust adhesion does not vary depending on the site on the surface of the elastomeric layer, and even if paper dust adheres to the surface of the elastomeric layer, it peels off, so the coefficient of friction is unlikely to change. As a result, no difference in the coefficient of friction occurs depending on the site on the surface of the elastomeric layer. As a result, conveyance failure (paper jamming) of the paper after long-term use can be eliminated.

[0044] As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the above embodiments at all, and various modifications are possible without departing from the spirit of the present invention.

Examples

[0045] Hereinafter, the present invention will be described in detail using examples and comparative examples.

[0046] (Example 1) <Preparation of rubber composition> 60 parts by mass of oil-extended EPDM, 20 parts by mass of non-oil-extended EPDM, 30 parts by mass of paraffin oil, 3 parts by mass of dispersant, 5 parts by mass of zinc oxide, 0.25 parts by mass of carbon black, 5 parts by mass of monoglyceride obtained by reacting glycerin and fatty acid, and 3 parts by mass of peroxide crosslinking agent were kneaded in a kneader, and then 50 parts by mass of IR was further kneaded in a kneader to prepare a rubber composition.

[0047] <Production of elastomeric layer> A mandrel (diameter 8 mm) was set in a molding die, the above rubber composition was injected, heated at 160 ° C for 40 minutes, then cooled and demolded to form an elastomeric layer made of a rubber elastomer with a thickness of 6 mm on the outer periphery of the mandrel.

[0048] (Example 2) 60 parts by mass of oil-extended EPDM, 20 parts by mass of non-oil-extended EPDM, 50 parts by mass of IR, 30 parts by mass of paraffin oil, 3 parts by mass of a dispersant, 5 parts by mass of zinc oxide, 0.25 parts by mass of carbon black, 5 parts by mass of a monoglyceride obtained by reacting glycerin and a fatty acid, and 3 parts by mass of a peroxide crosslinking agent were kneaded in a kneader to prepare a rubber composition.

[0049] (Examples 3 to 9) A rubber composition was prepared in the same manner as in Example 2 with the compounding composition (parts by mass) shown in Table 1 to form an elastomer layer.

[0050] (Comparative Examples 1 to 5) A rubber composition was prepared in the same manner as in Example 1 with the compounding composition (parts by mass) shown in Table 1 to form an elastomer layer.

[0051] The materials used were as follows. · Oil-extended EPDM: "Esprene 600F" manufactured by Sumitomo Chemical · Non-oil-extended EPDM: "Esprene 512F" manufactured by Sumitomo Chemical · IR: "Nipol IR2200" manufactured by Nippon Zeon · Paraffin oil: "Diana Process PS-430" manufactured by Idemitsu Kosan · Naphthene oil: "Diana Process NS-100" manufactured by Idemitsu Kosan · Dispersant: "AEROSIL R805" (hydrogenated isoprene) manufactured by EVONIK · Zinc oxide: reagent · Carbon black: "Shoublack MAF-G" manufactured by Cabot · Monoglyceride (i): "Poem M-200" (glycerin monocaprate) manufactured by Riken Vitamin, straight-chain saturated fatty acid with 8 carbon atoms · Monoglyceride (ii): "Poem M-300" (glycerin monolaurate) manufactured by Riken Vitamin, straight-chain saturated fatty acid with 12 carbon atoms · Monoglyceride (iii): "Rikemal S-100" (glycerin monostearate) manufactured by Riken Vitamin, straight-chain saturated fatty acid with 18 carbon atoms · Monoglyceride (iv): "Rikemal XO-100" manufactured by Riken Vitamin Co., Ltd. (glyceryl monooleate), a straight-chain unsaturated fatty acid with 18 carbon atoms · Monoglyceride (v): "Rikemal B-100" manufactured by Riken Vitamin Co., Ltd. (glyceryl monobehenate), a straight-chain saturated fatty acid with 22 carbon atoms · Sorbitan oleate: "Rikemal OV-250" manufactured by Riken Vitamin Co., Ltd. (sorbitan oleate) · Peroxide crosslinking agent: "Parkmill D" manufactured by NOF Corporation

[0052] Regarding the fabricated paper feed roll, the area ratio of the elastomer layer was measured. Also, the initial coefficient of friction of the elastomer layer was measured. In addition, an actual machine evaluation was conducted.

[0053] (Area ratio) Measurement was performed using a scanning probe microscope ("SPM-9700" manufactured by Shimadzu Corporation). As shown in Figure 2, an arbitrary surface of the elastomer layer was observed, and an arbitrary 20×20 μm range on that surface was divided into 64 parts. Sixteen squares arranged in the diagonal direction with diagonal lines were selected, and the area ratios of the first phase and the second phase within each 2.5 μm×2.5 μm square were measured respectively. A value corresponding to 14 or more (8.5 or more) of the 16 squares was adopted. · Measurement locations: Four locations in the circumferential direction at each of the left end, center, and right end of the elastomer layer (total of 12 locations) · Cantilever: SI-DF40 · Scanning range: 5.0000 μm · Scanning speed: 1.00 Hz

[0054] (Coefficient of friction) A 60 mm × 210 mm sheet of paper (P paper from Fuji Xerox Co., Ltd.) connected to a load cell was sandwiched between the paper feed roll and the polytetrafluoroethylene plate, and a vertical load W (W = 250 gf) was applied to the rotating shaft of the paper feed roll to press the paper feed roll against the polytetrafluoroethylene plate. Subsequently, under the conditions of a temperature of 23°C and a humidity of 55%, the paper feed roll was rotated at a peripheral speed of 300 mm / s. Before and after paper passage, the conveying force F (gf) of the generated paper 24 was measured with a load cell, and the coefficient of friction μ was obtained from the following formula (1) based on F (gf) and the load W (W = 250 gf). The initial coefficient of friction was rated as "〇〇" when it was 1.5 or more, "〇" when it was 1.0 or more and less than 1.5, and "×" when it was less than 1.0. (Formula (1)) μ = F (gf) / W (gf)

[0055] (Actual machine evaluation) The paper feed roll was incorporated into a commercially available copying machine with an FRR type paper feeding system to evaluate the paper feeding performance. Commercially available PPC paper was used as the paper, and 300,000 sheets (300K sheets) of paper were passed through to measure the number of paper jams. Those with 1 or fewer paper jams were rated as "○○〇", those with 2 or more and 5 or fewer paper jams were rated as "○〇", those with 6 or more and 10 or fewer paper jams were rated as "〇", and those with 11 paper jams were rated as "×". Also, when 11 paper jams occurred, the durability evaluation was aborted.

[0056] (Confirmation of uneven distribution) Measurement was performed using a scanning probe microscope ("SPM - 9700" manufactured by Shimadzu Corporation). As shown in Figure 2, an arbitrary surface of the elastic body layer was observed, and hardness measurement was performed to confirm the uneven distribution of monoglyceride. The proportion of monoglyceride in the first phase and the proportion of monoglyceride in the second phase can be determined by the difference from the hardness when no monoglyceride is contained. When there is no difference in the change in hardness, it corresponds to no uneven distribution, and when there is a difference in the change in hardness, it corresponds to uneven distribution.

[0057]

Table 1

[0058]

Table 2

[0059] In Comparative Examples 1 and 2, since they do not have monoglyceride, paper dust adhesion in the first phase is likely to occur. Also, due to the paper dust adhesion, the decrease in the friction coefficient cannot be suppressed, so they are inferior in the actual machine evaluation after long-term use. In Comparative Example 3, the polymer of the elastic body layer is composed only of EPDM. For this reason, the initial friction coefficient of the surface of the elastic body layer is low, and paper dust adhesion on the surface layer of the elastic body layer is likely to occur, so it is inferior in the actual machine evaluation after long-term use. In Comparative Example 4, since the amount of monoglyceride is less than 0.1 part by mass, paper dust adhesion in the first phase is likely to occur. Also, due to the paper dust adhesion, the decrease in the friction coefficient cannot be suppressed, so it is inferior in the actual machine evaluation after long-term use. In Comparative Example 5, since the amount of monoglyceride is more than 5 parts by mass, due to the bleed-out of monoglyceride, the initial friction coefficient of the surface of the elastic body layer decreases, and the paper conveyance property deteriorates.

[0060] On the other hand, in the Examples, the polymer of the elastic body layer is composed of EPDM and IR, and it has monoglyceride obtained by reacting glycerin and fatty acid. In the actual machine evaluation, even during long-term use of 300,000 sheets, there was almost no case where the paper could not be conveyed straight, and almost no conveyance failure (paper jam) occurred. In particular, when the monoglyceride is glycerin and an unsaturated fatty acid having 12 to 22 carbon atoms, when the monoglyceride is unevenly distributed in the first phase, and when the area ratio of the second phase is within a narrow range of 30 to 70%, the effect of suppressing conveyance failure (paper jam) in the actual machine evaluation was even more excellent.

[0061] As described above, the embodiments and examples of the present invention have been explained. However, the present invention is not limited to the above embodiments and examples at all, and various modifications are possible without departing from the spirit of the present invention.

Explanation of Signs

[0062] 10 Paper feed roll 12 shaft body 14 elastic body layer

Claims

1. A shaft body and an elastic body layer formed on the outer periphery of the shaft body, The elastic body layer contains a polymer and a monoglyceride, The content of the monoglyceride is 0.5 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the polymer, The elastic body layer has a first phase containing ethylene propylene diene rubber and a second phase containing at least one of isoprene rubber and natural rubber, a paper feed roll.

2. The monoglyceride is a monoglyceride having an aliphatic hydrocarbon group of C11 to 21, the paper feed roll according to claim 1.

3. The monoglyceride is a monoglyceride having an unsaturated aliphatic hydrocarbon group, the paper feed roll according to claim 1 or 2.

4. Within an arbitrary range of 2.5 μm × 2.5 μm square of the elastic body layer, the area ratio of the second phase is within the range of 30 to 70%, the paper feed roll according to claims 1 to 3.

5. The monoglyceride is present in the first phase at a higher concentration than in the second phase, the paper feed roll according to claims 1 to 4.

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