JP2008158031A - Developing roller, manufacturing method for developing roller, developing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing roller having an elastic layer formed from, as a base, rubber composed of ethylene, propylene, and a copolymer of three components and rendered conductive by the addition of carbon black, the developing roller being designed so as to have a high-precision shape, low hardness, low resistance, prevent soiling of a photoreceptor, nonuniform image density and density decrease, and meet an increase in the speed of an electrophotographic apparatus and an improvement in image quality. <P>SOLUTION: In the case of the developing roller in which the elastic layer is formed along the peripheral face of the shaft core body, the elastic layer contains, as rubber for the main component of the elastic layer, rubber comprising ethylene, propylene, copolymer of three components. The MD-1 hardness of the elastic layer is in the range of 5° to 38° inclusive. The quantity of extraction of the elastic layer by n-hexane is in the range of 0.0 mass% to 5.0 mass%, inclusive. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a copying machine, a printer or facsimile receiver, a developing roller used in contact with a photoreceptor incorporated in an apparatus employing an electrophotographic system, a developing device using the same, an image forming apparatus, and a developing roller It is related with the manufacturing method.

In electrophotographic apparatuses such as copying machines, facsimile machines, and printers, a photosensitive member (drum) that is a latent image carrier is charged or an electrostatic latent image is visualized. An elastic roller having a resistance) is generally used. In an electrophotographic apparatus of a one-component development system, a developer (toner) is moved from a developing roller that is in pressure contact with or close to the photosensitive member to develop an electrostatic latent image, and development is performed.
The developing roller used in such an electrophotographic apparatus is in pressure contact with or close to the photoreceptor with a predetermined contact width, and carries the developer thinned with a blade, so that it is easily deformed and excellent in deformation recovery. There is a need. Further, these developing rollers are required to have appropriate and uniform conductivity so as not to cause image unevenness.

In order to satisfy these requirements, conventionally, the developing roller according to the present invention has an elastic layer made of a rubber material imparted with conductivity formed on the outer periphery of the shaft core. In the contact development, the elastic layer of the developing roller needs to be in pressure contact with the photosensitive member with a predetermined contact width. When the hardness is reduced in order to obtain good followability to the surface of the photosensitive member, May cause contamination. In general, a developing roller using an elastic layer made of flexible and excellent silicone rubber can be mentioned. Silicone rubber itself is a relatively expensive material, and the developing roller is also relatively expensive. As a matter of course, it is desired to provide an inexpensive developing roller, and rubber materials used for the developing roller are studied over a wide variety and are properly used according to the purpose. Among them, a relatively inexpensive rubber made of a copolymer of ethylene and propylene (hereinafter abbreviated as EPM), a rubber made of a copolymer of ethylene, propylene and a third component (hereinafter abbreviated as EPDM). ) There is a way to use. However, in a conventional developing roller using EPDM, it is difficult to sufficiently reduce the hardness depending on the purpose, and there is much room for improvement. In addition, attempts have been made to reduce the hardness by blending liquid EPDM or liquid EPM (Patent Document 2). However, depending on the situation and purpose of use, a bleed problem may occur.

In addition, examples of the method for forming the elastic layer of the developing roller include several methods such as extrusion molding and injection molding. As described above, the developing roller is in pressure contact with or close to the photoconductor with a predetermined contact width, and carries the developer thinned by the blade, so that high dimensional accuracy is required. Of the above methods, the elastic body processed by extrusion does not have the shape accuracy for use as a developing roller as it is, so the surface is polished to a desired shape by a cylindrical grinder. Need to be processed. On the other hand, the elastic body layer of the developing roller according to the method in which the elastic body layer is arranged around the shaft body by injecting a liquid uncured material into the cylindrical mold and then heat-curing the shape of the mold to be used. Since reproduction is performed with a certain amount of shrinkage, it is possible to obtain one having a sufficiently satisfactory shape accuracy without polishing. Silicone rubber is an example of a liquid uncured material suitable for a method of being injected into a cylindrical mold and heat-cured, but is expensive as described above.
JP 7-219336 A Japanese Patent Laid-Open No. 11-202598

  In recent years, the required performance of the developing roller used in the electrophotographic apparatus has become more advanced as the speed of the electrophotographic apparatus increases and the image quality becomes higher, and further improvement is required. . In addition, there is a demand for high dimensional accuracy and at the same time low cost and stable performance.

  In particular, it is necessary for the contact development to have a low hardness and rubber elasticity for obtaining a predetermined contact width (nip width) with respect to the photoreceptor, and to have an electrical resistance characteristic called a semiconductive region. In particular, when liquid rubber is used for the elastic layer, a highly accurate shape is obtained by injecting a liquid uncured material into a cylindrical mold and heat-curing the elastic layer around the shaft. Is obtained. Further, it is required that the components contained in the elastic layer hardly bleed on the surface of the developing roller and do not cause contamination of the photoreceptor.

  An object of the present invention is to solve the problems in such a developing roller. In particular, the object of the present invention is to develop a rubber layer based on a rubber composed of a copolymer of a third component selected from ethylene, propylene, and dienes or polyenes, and having an elastic layer provided with conductivity by adding carbon black. The roller has a highly accurate shape, low hardness and low resistance, does not cause contamination of the photoreceptor, and can cope with high-speed electrophotographic equipment and high-quality image without unevenness in image density and density reduction. It is to obtain a developing roller.

  The developing roller refers to a latent image carrier for forming an electrostatic latent image by an electrophotographic method and a contact or pressure contact with the surface of the latent image carrier while carrying a developer in a thin film shape. In this state, the developer is supplied to the electrostatic latent image formed on the latent image carrier to develop the electrostatic latent image.

  In order to solve the above-mentioned problems, the present inventors have intensively studied and studied.

  According to the present invention, a developing roller using an elastic body layer based on a copolymer of a third component selected from ethylene, propylene, and a diene or a polyene and imparted with conductivity by adding carbon black. It has a highly accurate shape, achieves both low hardness and low resistance, and suppresses bleeding (oil transfer). In addition, contamination of the photoreceptor can be prevented.

  The developing roller of the present invention contains a rubber composed of a copolymer of a third component selected from ethylene, propylene, and a diene or polyene as a rubber that is a main component of the elastic layer, and the MD of the elastic layer. -1 hardness is in the range of 5 ° to 38 °, and the extraction amount of the elastic layer with n-hexane is 0.0% by mass to 5.0% by mass.

  An elastic body layer is formed using a copolymer rubber of a third component selected from ethylene, propylene, and a diene or polyene, and the MD-1 hardness of the elastic body layer is in the range of 5 ° to 38 ° and elastic. When the extraction amount of the body layer with n-hexane is 0.0% by mass or more and 5.0% by mass or less, it is a highly accurate dimensional shape, and it is possible to achieve both desired low hardness and low bleeding. .

  The developing roller of the present invention is a liquid having a viscosity of 100 Pa · s or more and 800 Pa · s or less as a third component copolymer selected from the ethylene, propylene, and diene or polyene contained in the elastic layer. Rubber is used, and the liquid rubber is preferably 80 to 100% by mass in the rubber component of the elastic layer.

In the developing roller of the present invention, the third component preferably has a structure having a vinyl group, and more preferably contains the structure of the chemical formula (I) or a structure derived therefrom.

The carbon black contained in the elastic layer of the developing roller of the present invention has a DBP absorption amount of 60 ml / 100 g or more and 110 ml / 100 g or less, and a ratio of volatile matter / nitrogen specific surface area of 1.4 × 10 ⁻⁴ g. / M ² or less is preferable. By using the above carbon black, it is easy to obtain a good dispersion state, and it is easy to impart conductivity to the rubber without increasing the hardness of the elastic layer more than necessary.

  In the developing roller of the present invention, the elastic layer is preferably crosslinked with an organic peroxide crosslinking agent, and the organic peroxide crosslinking agent is 1,3 bis (tertiary butyl peroxyisopropyl). Benzene, 2,5 dimethyl 2,5 (tertiary butyl peroxy) hexyne-3, n-butyl 4,4-diterebutyl peroxyvalerate, terebutyl peroxybenzoate, diterebutyl peroxydiisopropylbenzene, tele It is more preferable that it is 1 type, or 2 or more types chosen from the group of butyl cumyl peroxide, 2,5-dimethyl 2,5-diterebutyl peroxyhexane, diterebutyl peroxide.

  Moreover, it is preferable that the resin layer is coat | covered on the outer periphery of the elastic body layer of the image development roller of this invention. In the present invention, bleeding of components contained in the elastic layer is suppressed, but migration can be further prevented by forming a coating layer.

  Further, as a method for producing the developing roller of the present invention, a liquid rubber material is injected into a cavity of a mold heated to a predetermined temperature from an injection hole of an injection nozzle, and the liquid rubber material is crosslinked in the cavity. Preferably, it is formed by.

  In the developing device of the present invention, by providing the developing roller described above, the developing device can cope with higher speed of the electrophotographic apparatus and higher quality of the image without unevenness of image density and lowering of density.

  In addition, the image forming apparatus of the present invention is an image forming apparatus that can cope with higher speed and higher quality of the electrophotographic apparatus without unevenness of image density and lowering of density by providing the developing roller.

  As described above, the present inventors have developed a developing roller having a highly accurate dimensional shape, low hardness, low resistance, and no contamination of the photosensitive member. The present invention has found a developing apparatus and an image forming apparatus that can cope with high-speed electrophotographic apparatus and high-quality image quality without lowering the density, and a method for producing a high-precision developing roller at a relatively low cost. It came to complete.

  According to the present invention, a developing roller having an elastic body layer based on a rubber composed of a copolymer of a third component selected from ethylene, propylene, and a diene or polyene has a highly accurate shape and a low It is possible to obtain a developing roller that is hard and does not cause contamination of the photosensitive member, and does not have unevenness of image density or density reduction, and can cope with high-speed electrophotographic apparatus and high image quality. Further, a method for producing the developing roller having high accuracy and excellent performance as described above at a relatively low cost can be obtained. Further, in the developing device and the image forming apparatus using the developing roller of the present invention, the photosensitive member is not contaminated, and there is no unevenness of image density or density reduction, and the high-speed electrophotographic apparatus can be improved in quality. An image can be obtained.

The developing roller according to the present invention is a developing roller in which at least an elastic body layer is formed on the outer peripheral surface of the shaft core body, and the elastic body layer is a third component selected from ethylene, propylene, and diene or polyene. It contains a copolymer rubber, the MD-1 hardness of the elastic layer is in the range of 5 ° or more and 38 ° or less, and the extraction amount of the elastic layer with n-hexane is 0.0% by mass or more and 5. 0% by mass or less.
Hereinafter, the present invention will be described in more detail.

  1 and 2 schematically show an example of the structure relating to the developing roller of the present invention. The developing roller 1 illustrated in FIGS. 1 and 2 has a shaft core 11 that is usually formed of a metal conductive material as a shaft core at the center, and on the outer peripheral surface of the shaft core 11 as a roller layer. The elastic body layer (base layer) 12 is fixed to the outer peripheral surface of the elastic body layer 12, and a coating layer (surface layer) 13 is laminated on the outer peripheral surface of the elastic body layer 12. Here, a description will be given of a developing roller having two layers on the outer peripheral surface of the shaft core as described above.

  The shaft body 11 is of course a support member, but functions as an electrode of the developing member. The shaft body 11 has a columnar or hollow cylindrical shape and is formed of a metal conductive material. A core can be used. Even if such a developing roller is used with an electrical bias applied or grounded, the main body is made of a non-conductive material instead of being composed of a conductive material. It is also possible to use a material which is formed of a material and has a structure in which the surface thereof is subjected to a conductive treatment satisfying desired conductivity and a coating with a highly conductive coating layer.

  Examples of the material constituting the shaft core 11 include metals or alloys such as aluminum, copper alloys and stainless steel, iron plated with chromium and nickel, and conductive synthetic resins. In the developing roller used in the electrophotographic apparatus, the outer diameter of the conductive substrate that is the shaft core is usually in the range of 4 to 10 mm.

  The elastic body layer 12 serving as a base layer has flexibility, and can be formed as a molded body using rubber as a raw material main component. The raw material rubber of the elastic layer 12 contains at least a rubber made of a copolymer of ethylene, propylene, and a third component.

  The MD-1 hardness of the elastic layer 12 needs to be in the range of 5 ° to 38 °. When the MD-1 hardness is less than 5 °, it is difficult to maintain a highly accurate shape, and when the MD-1 hardness exceeds 38 °, it is difficult to stably obtain an appropriate nip width with the photoreceptor. . A preferable range of the MD-1 hardness is 15 ° or more and 30 ° or less.

  The amount of extraction of the elastic layer 12 with n-hexane needs to be 0.0 to 5.0% by mass. As the solvent to be used, a solvent having a low polarity is preferable, and n-hexane is used in the present invention. When the amount of extraction with n-hexane exceeds 5% by mass, although it depends on the components to be extracted, there is a problem in that the photoconductor is contaminated. A preferable range of the extraction amount with n-hexane is 0% by mass or more and 4% by mass or less.

  As the rubber used for the elastic body layer 12, a liquid rubber having a viscosity of 100 Pa · s or more and 800 Pa · s or less made of a copolymer of a third component selected from ethylene, propylene, and diene or polyene as a main component is used. The liquid rubber is preferably in a proportion of 80% by mass or more and 100% by mass or less in the rubber component of the elastic layer. The rubber component refers to a raw rubber and does not include various additive components, cross-linking agents, catalysts, and various dispersion accelerators that are used when forming a rubber molding.

  The viscosity of the liquid rubber is measured in an atmosphere of 25 ° C. ± 1 ° C. by putting 300 g of the liquid rubber composition into a test container and using a B-type viscometer BS (device name, manufactured by Toki Sangyo Co., Ltd.) as necessary. This was done by selecting an appropriate attached rotor.

  When the rubber composed of a copolymer of a third component selected from ethylene, propylene, and diene or polyene is in liquid form, the elastic layer is pivoted by injecting a liquid uncured material into a cylindrical mold and heat-curing it. There is an advantage that it is easy to obtain a highly accurate roller shape by the method of arranging around the body. However, a rubber composed of a copolymer of ethylene, propylene, and a third component has a problem of poor chemical reactivity, a low vulcanization rate, and a low efficiency for use as a liquid rubber. The choice of structure is important.

  Examples of the copolymer of the third component selected from liquid ethylene, propylene, and diene or polyene include the following commercially available products in which the third component is 5-ethylidene-2-norbornene. “TRILENE 66” (trade name, manufactured by Uniroyal Chemical Company Inc.), “TRILEN 67” (trade name, manufactured by Uniroyal Chemical Company Inc.).

In the present invention, the third component preferably has a structure having a vinyl group, and more preferably a polyene having one polymerizable double bond and two or more other double bonds. Examples of the third component having such a structure include those containing the structure of chemical formula (I) or a structure derived therefrom.

... Chemical formula (I)
In the formula (I), n is an integer of 1 to 5, R1 is an alkyl group having 1 to 5 carbon atoms, R
2 and R3 are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.
Specific examples of the alkyl group having 1 to 5 carbon atoms include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, and t-butyl. Group, n-pentyl group and i-pentyl group.

  When the third component is represented by the chemical formula (1), two double bonds can be introduced into the polymer when one third component is copolymerized. This shows that when the same number of moles as the diene-based third component is used, it is possible to introduce double double bonds in calculation, and the crosslinking reaction is accelerated as the amount of double bonds increases. I can do it. Even in the case of liquid rubber, the crosslinking reaction can be sufficiently accelerated. Specific examples of such a third component include 4-ethylidene-1,6-octadiene, 7-methyl-4-ethylidene-1,6-octadiene, 7-methyl-4-ethylidene-1,6-nonadiene, 7-ethyl-4-ethylidene-1,6-nonadiene, 6,7-methyl-4-ethylidene-1,6-octadiene, 6,7-dimethyl-4-ethylidene-1,6-nonadiene, 4-ethylidene- 1,6-decadiene, 7-methyl-4-ethylidene-1,6-decadiene, 7-methyl-6-propyl-4-ethylidene-1,6-octadiene, 4-ethylidene-1,7-nonadiene, 8 -Methyl-4-ethylidene-1,7-nonadiene (EMN), 4-ethylidene-1,7-undecadiene, 8-methyl-4-ethylidene-1,7-undecadiene, 7,8-dimethyl- 4-ethylidene-1,7-nonadiene, 7,8-dimethyl-4-ethylidene-1,7-decadiene, 7,8-dimethyl-4-ethylidene-1,7-undecadiene, 8-methyl-7-ethyl- 4-ethylidene-1,7-undecadiene, 7,8-diethyl-4-ethylidene-1,7-decadiene, 9-methyl-4-ethylidene-1,8-decadiene, 8,9-dimethyl-4- Ethylidene-1,8-decadiene, 10-methyl-4-ethylidene-1,9-undecadiene, 9,10-dimethyl-4-ethylidene-1,9-undecadiene, 11-methyl-4-ethylidene-1,10 -Dodecadiene, 10,11-dimethyl-4-ethylidene-1,10-dodecadiene. Among them, 6,7-dimethyl-4-ethylidene-1,6-octadiene having a vinyl group, 6,7-dimethyl-4-ethylidene-1,6-nonadiene, 7-methyl-6-propyl-4-ethylidene- 1,6-octadiene, 8-methyl-4-ethylidene-1,7-nonadiene (EMN), 7,8-dimethyl-4-ethylidene-1,7-nonadiene, 9-methyl-4-ethylidene-1,8 Decadiene, 8,9-dimethyl-4-ethylidene-1,8-decadiene is preferred. These can be used alone or in combination of two or more.

  In addition to the rubber made of a copolymer of a third component selected from ethylene, propylene, and diene or polyene, other rubbers can be blended. The rubber to be blended is not particularly limited, but it is necessary to consider compatibility during blending. Moreover, the rubber | gum which can be blended may be used in combination of 2 or more type as needed. Examples of the rubber to be blended include the following. Other ethylene-propylene-diene copolymer rubber (EPDM), acrylonitrile butadiene rubber (NBR), chloroprene rubber (CR), natural rubber (NR), isoprene rubber (IR), styrene-butadiene rubber (SBR), fluorine rubber , Rubber materials of silicone rubber, epichlorohydrin rubber, NBR hydride, polysulfide rubber, urethane rubber. The rubber to be blended may be a normal solid rubber, but it is more preferable if it is liquid.

  The rubber material, that is, rubber containing a third component copolymer selected from ethylene, propylene, and a diene or polyene, is blended with various additives as necessary, and an elastic layer. Can be molded. As additives, conductive agents, non-conductive fillers, etc., which are components necessary for the functions required for the elastic layer itself, depending on the use of the developing roller, and also used when forming rubber moldings Various additive components are used. As various additive components, a crosslinking agent, a catalyst, a dispersion accelerator, and various additives can be appropriately blended into the main rubber material. These addition amounts can also be selected according to the characteristics required for the intended application.

  Examples of the conductive agent include carbon black and graphite. In addition, various conductive metals or alloys such as aluminum, copper, tin, stainless steel, various conductive metal oxides such as tin oxide, indium oxide, tin oxide antimony monoxide solid solution, tin oxide indium monoxide solid solution, and their conductivity A fine powder of an insulating material coated with a conductive material can be used. Among these, carbon black can be obtained relatively easily and can impart good conductivity.

In addition, as a means for imparting conductivity to the rubber material, a conductive polymer compound can be used. As host polymers, polyacetylene, poly (p-phenylene), polypyrrole, polythiophene, poly (p-phenylene oxide), poly (p-phenylene sulfide), poly (p-ferene vinylene), poly (2,6-dimethylphenylene) Oxide), poly (bisphenol-A-carbonate), polyvinylcarbazole, polydiacetylene, poly (N-methyl-4-vinylpyridine), polyaniline, polyquinoline, poly (phenylene ether sulfone), and AsF ₅ as a dopant. , I ₂ , Br ₂ , SO ₃ , Na, K, ClO ₄ , FeCl ₃ , F, Cl, Br, I, and Kr ions, Li, and TCNQ are used.

  When carbon black is used as a conductive agent for the elastic layer, the DBP absorption amount of the carbon black isolated from the elastic layer is preferably in the range of 60 ml / 100 g to 110 ml / 100 g. Within this range, since the structure structure is not increased more than necessary, the elastic modulus of the conductive rubber roller can be kept low. The DBP absorption amount of carbon black indicates the DBP absorption amount per 100 g of carbon black, and is one of the indexes for determining the size of the structure of carbon black. The structure of carbon black is formed by uniting carbon black unit particles in a chain shape, and the size of the carbon black determines the electrical conductivity of the carbon black. In the present invention, the carbon black in the elastic layer is heated to 750 ° C. in a nitrogen atmosphere to burn the rubber component, and then centrifuged in a solvent having a specific gravity adjusted as necessary. Isolated by separating from other inorganic residues. Further, the DBP absorption amount is measured in accordance with JISK6217-4.

When the DBP absorption amount of the carbon black is 60 ml / 100 g or more, it becomes easy to uniformly disperse in the rubber component. . Further, when the DBP absorption amount of the carbon black is 110 ml / 100 g or less, it is hardly affected by shearing when used for a liquid rubber, which will be described later, and is molded by injecting a liquid uncured material into a cylindrical mold. In this case, since the carbon black distribution in the elastic body can be made uniform, stable conductivity without uneven resistance can be obtained.
When trying to obtain the same conductivity within the range of 60 ml / 100 g or more and 110 ml / 100 g or less of the DBP absorption amount of the carbon black, the higher the value, the easier it is to obtain the desired conductivity with a smaller addition amount. In addition, the lower the value, the larger the amount of carbon black added, and the easier it is to obtain resistance stability.

When carbon black is used as the conductive agent in the elastic layer, the ratio of carbon black volatile matter / nitrogen specific surface area is preferably 1.4 × 10 ⁻⁴ g / m ² or less. When the ratio of volatile matter / nitrogen specific surface area of carbon black is 1.4 × 10 ⁻⁴ g / m ² or less, reaggregation in the liquid rubber is suppressed, and a uniform elastic body layer is easily obtained. Furthermore, it becomes difficult for agglomerates to be present at the time of molding, and it is possible to suppress the occurrence of leaks when used as a developing port. This is because if the ratio of the volatile matter / nitrogen specific surface area becomes too high, the physical adsorption force with the polymer chain on the carbon black surface becomes weak, and when subjected to the external force of the shear, It is conceivable to promote aggregation.
The volatile content of carbon black indicates the amount of functional groups such as carboxykyl groups, hydroxyl groups, and quinone groups present on the surface of the carbon black, and the dispersibility of the carbon black, stability in solvents, and ease of reaggregation. Affect. In the present invention, the volatile matter is measured in accordance with JIS K6221.

  The nitrogen specific surface area of carbon black indicates the amount of nitrogen adsorbed per gram, and is a numerical value related to the specific surface area of carbon black, in other words, the particle size. The ratio of the volatile content / nitrogen specific surface area indicates the volatile content per surface area of the carbon black and is an index indicating the chemical properties of the carbon black surface. In the present invention, the nitrogen specific surface area is measured in accordance with JISK6217-2.

The carbon black used in the present invention is not particularly limited as long as it has the above characteristics, whether it is a commercially available product, a product obtained by treating a commercially available product, or a newly produced product. . Examples thereof include oil furnace black, gas furnace black, channel type carbon black, and those obtained by oxidizing these carbon blacks.
The amount of carbon black added is not particularly limited because it varies depending on the type of carbon black to be used. Usually, it is 5 parts by weight or more and 85 parts by weight or less, preferably 10 parts by weight or more with respect to 100 parts by weight of rubber. In the range of 70 parts by weight or less, it is appropriately set according to the conductivity and hardness required for the developing roller. If the blending amount of carbon black is 60 parts by weight or less, the conductivity and hardness of the rubber roller will not be too high. Furthermore, since the uniformity of distribution in the resin layer is increased, the uniformity of conductivity is also improved. On the other hand, if the blending amount of carbon black is 5 parts by weight or more, a practically acceptable level of conductivity can be ensured. Further, the added carbon black can be sufficiently percolated, and the conductivity can be stabilized.

  The average particle diameter of the carbon black used in the present invention is not particularly limited, but there is a preferable range depending on the volatile matter / nitrogen specific surface area ratio from the viewpoint of dispersibility in rubber and conductivity imparting property.

  As a means for dispersing the conductive agent in the form of fine powder of carbon black in the main rubber material, a conventionally used means such as a roll kneader, a Banbury mixer, a ball mill, a sand grinder, a paint shaker, What is necessary is just to use suitably according to the rubber material of a main component.

  Examples of the plasticizer added to the elastic layer for the purpose of adjusting the hardness include dioctyl phthalate, dibutyl phthalate, dioctyl separate, and dioctyl adipate. However, in the present invention, in order to keep the extraction amount of the elastic layer with n-hexane low, it is preferable that the addition amount of the plasticizer is small.

  Examples of the nonconductive filler that can be added to the elastic layer include diatomaceous earth, quartz powder, dry silica, wet silica, titanium oxide, zinc oxide, aluminosilicate, and calcium carbonate.

  In the usual case, the elastic layer of the present invention is prepared by once preparing an unvulcanized compounded rubber in the same manner as when general rubber is crosslinked, and then molding this compounded rubber into the intended shape, followed by crosslinking. It is manufactured by. Here, an organic peroxide, sulfur, a sulfur compound, a sulfur-containing organic vulcanizing agent, or a triazine compound is used as the crosslinking agent, and it is particularly preferable that the crosslinking is performed with an organic peroxide crosslinking agent.

  In general EPDM and the copolymer of ethylene, propylene, and the third component of the present invention, the rubber contains unsaturated groups and has many crosslinking points. Therefore, excellent rubber properties are easily obtained. Although simple comparison is not possible, there is a strong tendency to obtain superiority in set performance (compression set) compared to sulfur-based crosslinking.

  Examples of the organic peroxide include 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane, di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide, 2 , 5-Di-methyl-2,5-di (t-butylperoxy) hexane, 2,5-di-methyl-2,5-di (t-butylperoxy) hexyne, 1,3-bis (t -Butylperoxy-isopropyl) benzene, t-butylperoxy-isopropyl carbonate, acetylcyclohexylsulfonyl peroxide, isobutyl peroxide, di-isopropyl peroxydicarbonate, di-allyl peroxydicarbonate, di-n-propylper Oxydicarbonate, di- (2-ethoxyethyl) peroxydicarbonate, (Methoxyisopropyl) peroxydicarbonate, di (2-ethylhexyl) peroxydicarbonate, t-hexylperoxyneohexanate, di (3-methyl-3-methyloxybutyl) peroxydicarbonate, t-butylperoxyneo Decanate, t-hexyl peroxyneodecanate, t-butyl peroxyneohexanate, 2,4-dichlorobenzoyl peroxide, t-hexyl peroxypivalate, t-butyl peroxypivalate, 3, 3, 5-trimethylhexanoyl peroxide, octanoyl peroxide, decanoyl peroxide, lauroyl peroxide, cumylperoxyoctate, acetyl peroxide, t-butylperoxy (2-ethylhexanate), benzoyl Oxide, t-butylperoxyisobutyrate, 1,1-bis (t-butylperoxy) cyclohexane, t-butylperoxymaleic acid, t-butylperoxylaurate, t-butylperoxy3,3 , 5-trimethylhexanate, cyclohexanone peroxide, t-butylperoxyallyl carbonate, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, 2,2-bis (t-butylperoxy) octane , T-butyl peroxyacetate, 2,2-bis (t-butylperoxy) butane, t-butylperoxybenzoate, n-butyl-4,4-bis (t-butylperoxy) valerate, di-t -Butyl diperoxyisophthalate, methyl ethyl ketone peroxide, α, α'- (T-butylperoxy-m-isopropyl) hexane, di-isopropylbenzene-hydroperoxide, p-menthane hydroperoxide, 1,1,3,3-tetramethylbutylhydroperoxide, 2,5-dimethyl Examples include hexane-2,5-dihydroperoxide, cumene hydroperoxide, and t-butyl hydroperoxide.

  Among these, 2,5-di-methyl-2,5-di (t-butylperoxy) hexane and 2,5-di-methyl-2,5-di (t-butylperoxy) hexyne are compared. It is more preferable because it is odorless and easily adaptable to injection molding at high temperatures.

  In addition, sulfur-based crosslinking agents (sulfur / sulfur compounds) include powdered sulfur, sulfur flower, highly dispersible sulfur, insoluble sulfur, precipitated sulfur, surface-treated sulfur, colloidal sulfur, sulfur chloride, sulfur monochloride, and sulfur dichloride. Can be mentioned. Examples of the sulfur-containing organic vulcanizing agent include morpholine disulfide, alkylphenol disulfides, thiuram disulfide, N, N'-dithio-bis (hexahydro-2H-azepinone-2), 2- (4'-morpholinodithio) benzothiazole. Is mentioned. Furthermore, examples of the triazine compound include 2,4,6-trimercapto-S-triazine and 2-di-n-butylamino-4,6-dimercapto-S-triazine. These crosslinking agents can be used alone or in combination of two or more.

  The amount of these crosslinking agents is usually 0.1 parts by mass or more and 15 parts by mass or less, and preferably 0.5 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the rubber component.

  When an organic peroxide is used as the crosslinking agent, sulfur, p-quinonedioxime, p-benzoquinonedioxime, p, p'-dibenzoylquinonedioxime is used in combination with the organic peroxide. N-methyl-N'-4-dinitroaniline, N, N'-m-phenylene dimaleimide, dipentamethylene thiuram pentasulfide, dinitrosobenzene, divinylbenzene, triallyl cyanurate, triallyl isocyanurate, triazine thiol , Ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, dipropylene glycol dimethacrylate, trimethylolpropane triacrylate Rate, erythritol tetramethacrylate, trimethylolpropane trimethacrylate, diallyl melamine, trimethacrylate, dimethacrylate, divinyl adipate, vinyl butyrate, vinyl stearate, liquid polybutadiene rubber, liquid polyisoprene rubber, liquid styrene-butadiene rubber, liquid acrylonitrile A co-crosslinking agent of butadiene rubber, magnesium diacrylate, calcium diacrylate, aluminum acrylate, zinc acrylate, stannous acrylate, zinc methacrylate, magnesium methacrylate, or zinc dimethacrylate can be blended. These co-crosslinking agents can be used alone or in combination of two or more. The compounding amount of the co-crosslinking agent is usually 0.5 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the rubber component.

  It has been confirmed that by adding triallyl isocyanurate to the rubber comprising the copolymer of ethylene, propylene and the third component of the present invention, the crosslinking efficiency is increased and the set performance is improved. The amount of triallyl isocyanurate is usually 0.5 parts by mass or more and 20 parts by mass or less as described above, but preferably 2 parts by mass or more and 5 parts by mass or less.

  Moreover, when using a sulfur type crosslinking agent (vulcanization) as a crosslinking agent, a vulcanization accelerator can be used. Examples of such vulcanization accelerators include the following. Aldehyde ammonia such as hexamethylenetetramine, acetaldehyde / ammonia; n-butyraldehyde / aniline condensate, butyraldehyde / monobutylamine condensate, heptaldehyde / aniline condensate, aldehyde amines such as tricrotonylidene / tetramine condensate Guanidine salts, such as diphenylguanidine, di-o-tolylguanidine, ortho-tolyl-biguanide, dicatechol, diort-tolyl-guanidine salt of boric acid; imidazolines, such as 2-mercaptoimidazoline; 2-mercaptobenzothiazole, 2-mercapto Thiazoline, dibenzothiazyl disulfide, zinc salt of 2-mercaptobenzothiazole, sodium salt of 2-mercaptobenzothiazole, 2-mercaptobenzothiazole Chlorhexylamine salt, 2- (2,4-dinitrophenylthio) benzothiazole, 2- (N, N-diethylthio-carbamoylthio) benzothiazole, 2- (4'-morpholino-dithio) benzothiazole, 4-morpholino N-cyclohexyl-2-benzothiazole sulfenamide, N, N-dicyclohexyl-2-benzothiazyl sulfenamide, N-oxydiethylene-2-benzothiazyl sulfenamide , Sulfenamides such as N, N-diisopropyl-2-benzothiazyl sulfenamide, Nt-butyl-2-benzothiazyl sulfenamide; thiocarbanide, ethylene thiourea (2-mercaptoimidazoline), diethyl Thiourine Thioureas such as dibutyl thiourea, mixed alkyl thiourea, tolyl methyl thiourea, dilauryl thiourea; sodium dimethyl dithiocarbamate, sodium diethyl dithiocarbamate, sodium di-n-butyl carbamate, lead dimethyl dithiocarbamate , Lead diamyl dithiocarbamate, zinc diamyl dithiocarbamate, zinc diethyl dithiocarbamate, zinc di-n-butyl dithiocarbamate, zinc dibenzyl dithiocarbamate, zinc N-pentamethylene dithiocarbamate, zinc ethylphenyl dithiocarbamate Selenium dimethyl dithiocarbamate, selenium diethyl dithiocarbamate, tellurium diethyl dithiocarbamate, cadmium diethyl dithiocarbamate, di Dithiocarbamates such as copper methyl dithiocarbamate, iron dimethyl dithiocarbamate, bismuth dimethyl dithiocarbamate, piperidine dimethyl dithiocarbamate, pipecoline methylpentamethylene dithiocarbamate, activated dithiocarbamate; tetramethylthiuram monosulfide, tetrasulfide Methylthiuram disulfide, active tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, N, N'-dimethyl-N, N'-diphenylthiuram disulfide, dipentamethylenethiuram disulfide, dipentamethylene Thiurams such as thiuram tetrasulfide, mixed alkyl thiuram disulfide; isopropyl xanthate sodium Xanthates such as zinc, isopropyl / zinc xanthate, butyl / zinc xanthate; 4,4'-dithiodimorpholine, aminodialkyldithiophosphate, zinc-o, on-butyl phosphorodithioate, 3-mercapto Imidazoline-thione-2, thioglycolate. These vulcanization accelerators can be used alone or in combination of two or more. The compounding amount of the vulcanization accelerator is usually 0.1 parts by mass or more and 20 parts by mass or less, preferably 0.2 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the rubber component.

  Moreover, in addition to the said crosslinking agent (vulcanizing agent) and a vulcanization accelerator, a vulcanization | cure acceleration | stimulation adjuvant can also be added as needed. Examples of such vulcanization acceleration aids include the following. Magnesium oxide, zinc white, activated zinc white, surface-treated zinc white, zinc carbonate, composite zinc white, composite active zinc white, surface-treated magnesium oxide, calcium hydroxide, ultrafine calcium hydroxide, lead monoxide, resurge, lead red Metal oxides such as lead white; organic acids (salts) such as stearic acid, oleic acid, lauric acid, zinc stearate, calcium stearate, potassium stearate and sodium stearate. Of these, zinc white and stearic acid are particularly preferred. These vulcanization acceleration aids can be used alone or in admixture of two or more. The amount of the vulcanization acceleration aid is usually 0.5 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the rubber component.

  In addition to the rubber composition of the present invention, an ultraviolet absorber, a light stabilizer, a flame retardant, an antistatic agent, a conductive plasticizer, a liquid rubber, a functional group-containing oligomer, a colorant, an oil resistance improver, a foaming agent, A scorch inhibitor, a tackifier, a water-removing agent, an activator, a wax, a coupling agent, a peptizer, an antibacterial agent, a foaming aid, and a processing aid can be blended.

  In preparing the rubber used for the elastic layer of the present invention, conventionally known kneaders, extruders, and vulcanizers can be used. Although there are no particular limitations on the blending method and blending order of other polymers mixed with the rubber of the present invention, fillers, plasticizers, vulcanizing agents, etc., using a device such as a Banbury mixer, a modified ethylene-based copolymer is used. An example is a method in which a polymerized rubber, a filler, and a softening agent are mixed, and then a crosslinking agent is added using an apparatus such as a roll.

In particular, when liquid rubber is used, a method of mixing using a static mixer can be mentioned.
Although there is no particular limitation on the thickness of the elastic layer unless the outer diameter accuracy of the developing roller to be manufactured is impaired, generally, if the thickness of the elastic layer is excessively increased, the production cost of the rubber molded body is reduced. It becomes difficult to keep within the proper range. Considering these practical restrictions, the thickness of the elastic layer is preferably 6.0 mm or less, more preferably 5.0 mm or less. Accordingly, the thickness of the elastic layer is preferably selected in the range of 0.5 mm or more and 6.0 mm or less, and more preferably selected in the range of 1.0 mm or more and 5.0 mm or less. . The thickness of the elastic body layer is appropriately selected according to the hardness.

  According to the method for producing an elastic layer of the present invention, a liquid rubber material is injected from an injection hole of an injection nozzle into a cavity of a mold heated to a predetermined temperature, and the liquid rubber material is crosslinked in the cavity. The forming method is preferred. By molding in the mold, it becomes possible to create a more accurate shape, and at the same time, it becomes easy to obtain an elastic body layer having low hardness by using liquid rubber.

  As described above, the coating layer (surface layer) 13 is laminated on the outer peripheral surface of the elastic body layer 12.

  In the present invention, the coating layer 13 is not an essential requirement, but the formation of the coating layer can further prevent bleeding and migration of components contained in the elastic layer, and therefore, it is preferably coated according to the purpose. .

  In the present invention, the component for forming the coating layer 13 as the surface layer is not particularly limited, but a polyamide resin, a urethane resin, or a urea resin is particularly preferable from the viewpoint of self-film reinforcing property and developer charging property. Used. From the viewpoint of providing the coating layer 13 with an action of suppressing bleeding from the elastic layer, a crosslinked rubber is preferable.

  Urethane resins include those obtained by blending carbon black in a polyurethane prepolymer and crosslinking the prepolymer, or by blending a conductive material with a polyol and then using this polyol as a polyisocyanate by the one-shot method. What was obtained by the method of making it react with soot is mention | raise | lifted.

  In this case, the polyhydroxyl compound used for obtaining the polyurethane includes a polyol used for producing a general flexible polyurethane foam or urethane elastomer, a polyether polyol having a polyhydroxyl group at the terminal, a polyester polyol, and a copolymer of both. In addition to the polyether polyester polyol, it is possible to use a polyolefin polyol such as polybutadiene polyol or polyisoprene polyol, or a general polyol such as a so-called polymer polyol obtained by polymerizing an ethylenically unsaturated monomer in the polyol. it can.

  In addition, as the isocyanate compound, polyisocyanate similarly used for producing general flexible polyurethane foam and urethane elastomer, that is, tolylene diisocyanate (TDI), crude TDI, 4,4'-diphenylmethane diisocyanate (MDI), crude MDI, aliphatic polyisocyanate having 2 to 18 carbon atoms, alicyclic polyisocyanate having 4 to 15 carbon atoms, mixtures and modified products of these polyisocyanates, and prepolymers obtained by partially reacting with polyols Used.

  Examples of the urethane resin include one-pack type and two-pack type containing polyisocyanate, and an epoxy resin or a melamine resin may be used as a crosslinking agent as necessary. Examples of the polyamide resin include the following. Polyamides obtained from polycondensation between polyamides 6,6,6,6,10,6,12,11,12,12,12 and different monomers of those polyamides. From the viewpoint of workability, alcohol-soluble ones are preferably used. Examples thereof include those obtained by adjusting the molecular weight of a polyamide terpolymer or quaternary copolymer, or those obtained by methoxymethylating polyamide 6 or polyamide 12 to make them soluble in alcohol or water.

  One or two or more of urethane resins, polyamide resins, and other modified resins can be mixed and used, and development suitable for the development system can be made by selecting and using them appropriately according to the development system. The charge amount of the agent can be obtained.

  Furthermore, in order to form the coating layer 13 as a surface layer with good film formability, a conductive agent and a non-conductive filling are used as components necessary for the function required for the coating layer itself, in accordance with the individual use of the elastic roller. An agent can be added. Further, various additive components (crosslinking agent, catalyst, dispersion accelerator) used when forming and laminating the outer periphery of the elastic body layer 12 may be appropriately mixed with various additives as the main component resin material. it can. In addition, the additive of a conductive agent and a nonelectroconductive filler can be suitably selected according to the resin material of a main component from what was illustrated as an additive which can be previously contained in an elastic body layer. Moreover, the addition amount can be suitably selected according to the addition purpose, as long as the characteristics of the coating layer to be formed are maintained within the range where the effects of the present invention are exhibited.

  The elastic modulus of the coating layer 13 is not particularly limited as long as the film property and durability are practically obtained. The covering layer 13 is desired to exhibit high followability to deformation of the elastic body layer 12, and therefore, the film body forming the covering layer preferably has a low hardness and elastic modulus.

  The thickness of the covering layer 13 is preferably selected to be 2 μm or more in order to ensure sufficient wear resistance. On the other hand, the developing roller is an elastic roller having conductivity, and in this case, in order to achieve uniform conductivity, the thickness of the coating layer is preferably limited to 100 μm or less. Moreover, if the thickness of the coating layer is 2 μm or more, it is easy to apply and form uniformly on the elastic layer surface with a desired thin film thickness, while the hardness of the coating layer is the hardness of the elastic layer. Although it is higher than the hardness, a film thickness of 100 μm or less is preferable because the influence on the deformability of the entire developing roller does not increase. Further, the thickness of the coating layer may be appropriately selected according to the hardness within the above range. The thickness of the coating layer of the present invention is determined by measuring a cross section with an optical microscope using a sample cut out from a roller.

  For forming the coating layer 13, it is possible to use a method in which a polymer raw material, which is a raw material of the film body, is applied in the form of liquid or solution to the surface of the elastic body layer, and then the film body is formed. The coating method of the film body material is not particularly limited, but the resin material is uniformly coated on the surface of the elastic layer with a desired thickness by air spraying, roll coating, curtain coating, or dipping. Thereafter, in order to obtain a film body, heat treatment may be performed as necessary.

  The two-layer developing roller in which the elastic body layer 12 and the coating layer 13 are laminated in this order on the shaft core 11 has been described above. The layer configuration on the outer periphery of the shaft core in the developing roller according to the present invention is described above. A developing roller having a single layer structure in which the coating layer 13 is not provided may be used. Similarly, the layer structure on the outer periphery of the shaft core in the developing roller according to the present invention may have a multilayer structure of three or more layers. Examples include a developing roller in which another layer is provided between the elastic body layer 12 and the covering layer 13, and a developing roller in which the elastic body layer 12 itself is composed of a plurality of layers. In any configuration, there is no problem as long as the effect of the present invention can be obtained.

  As described above, the developing roller of the present invention is a developing roller having a highly accurate shape, low hardness and hardly causing contamination of the photoreceptor. Because of this advantage, when used as a developing roller in an electrophotographic apparatus, the photosensitive member is not contaminated, and there is no unevenness of image density and no decrease in density. Even in a high-speed electrophotographic apparatus, a high-quality image is obtained. It is possible to obtain

  FIG. 3 is a cross-sectional view showing a schematic configuration of the developing device and the image forming apparatus used as the developing roller of the present invention. The photosensitive drum 21 serving as a latent image carrier rotates in the direction of the arrow, is uniformly charged by a charging member 26 for charging the photosensitive drum 21, and is a laser as an exposure unit that writes an electrostatic latent image on the photosensitive drum 21. An electrostatic latent image is formed on the surface of the light 25. The electrostatic latent image is developed by applying a developer by the developing device 2 disposed in contact with the photosensitive drum 21 and visualized as a developer image. Development is so-called reversal development in which a developer image is formed in the exposed portion. The visualized developer image on the photosensitive drum 21 is transferred to a transfer sheet 36 as a recording medium by a transfer roller 31 as a transfer member. The transfer paper 36 to which the developer image has been transferred is fixed by the fixing device 29, discharged outside the device, and the printing operation is completed. On the other hand, the untransferred developer remaining on the photosensitive drum 21 without being transferred is scraped off by a cleaning blade 28, which is a cleaning member for cleaning the surface of the photoreceptor, and stored in a waste developer container 27 for cleaning. The photosensitive drum 21 repeats the above operation. The developing device 2 includes a developing container that contains a non-magnetic developer 23 as a one-component developer, and a developer carrying member that is located in an opening extending in the longitudinal direction in the developing container and is opposed to the photosensitive drum 21. The developing roller 1 is provided so that the electrostatic latent image on the photosensitive drum 21 is developed and visualized. The electrophotographic process cartridge includes a developing roller 1 and includes at least one of a photosensitive drum 21, a charging member 26, a cleaning member 28, and a transfer roller 31, and these are integrally held. And is detachably provided in the image forming apparatus. During image formation, the developing roller 1 is in contact with the photosensitive drum 21 with a contact width. In the developing device 2, the developer application member 22 is brought into contact with the contact portion of the regulating blade 24, which is a developer amount regulating member, with the surface of the developing roller 1 on the upstream side in the rotation direction of the developing roller 1 in the developing container. And is rotatably supported. As the structure of the developer application member 22, a foamed skeleton-like sponge structure or a fur brush structure in which rayon and polyamide fibers are planted on the shaft core body is supplied with the developer 23 to the developing roller 1 and undeveloped development. It is preferable from the point of stripping off the agent. An elastic roller having a diameter of 16 mm in which polyurethane foam is provided on the shaft core can be used. The contact width of the developer application member 22 with respect to the developing roller 1 is preferably 0.5 mm or more and 3.0 mm or less, and the developing roller 1 preferably has a relative speed at the contact portion.

  Hereinafter, the present invention will be described more specifically with reference to examples. Here, a description will be given of a developing roller having two layers on the outer peripheral surface of the shaft core as described above. These examples are examples of the best mode of the present invention, but the present invention is not limited to the examples. The developing roller manufactured by the method shown in the embodiment can be suitably used as a developing roller used in an electrophotographic apparatus in its application.

[Example 1] Developing roller 1
An SUS metal core (diameter 8 mm) with nickel plating applied as a shaft core was further applied and baked with an adhesive.

A rubber having a viscosity of 30 Pa · s made of a copolymer using ethylene, propylene, and 6,7-dimethyl-4-ethylidene-1,6-octadiene as a third component as a rubber component used in the elastic layer [hereinafter, Rubber A having a viscosity of 120 Pa · s consisting of a copolymer using ethylene, propylene, and 6,7-dimethyl-4-ethylidene-1,6-octadiene as the third component [hereinafter referred to as rubber A] B), 40 parts by weight of rubber A and 60 parts by weight of rubber B, 5 parts by weight of zinc oxide, 1.5 parts by weight of stearic acid, carbon black “Toka Black # 7360SB” ( (Trade name, manufactured by Tokai Carbon Co., Ltd.) [Hereinafter referred to as carbon black H] 60 parts by mass was kneaded for 10 minutes in a closed mixer adjusted to 50 ° C. to obtain a raw material compound. It was manufactured. Furthermore, with respect to the rubber content (rubber A100 parts by mass), 7.5 parts by mass of “Perhexine 25B-40” (trade name, product name manufactured by NOF Corporation; 40% by mass), triallyl isocyanurate “TAIC” (Product name, manufactured by Nippon Kasei Co., Ltd.) 3 parts by mass was added and kneaded for 10 minutes in a two-roll machine cooled to 20 ° C. to obtain a compound for elastic layer (liquid). This liquid rubber compound is poured into a cavity formed in a mold, the mold is heated at 150 ° C. for 20 minutes to crosslink the liquid rubber, cooled, and then removed from the mold to form an elastic layer having a thickness of 4 mm. A roller provided on the outer periphery of the shaft core was produced.
Here, the viscosity of the rubber blended with 40 parts by mass of rubber A and 60 parts by mass of rubber B was 100 Pa · s.

  Next, the solid content of the isocyanate “Coronate L” (trade name, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a curing agent is 10 mass relative to the solid content of 100 parts by weight of the polyol “Nipporan 5033” (trade name, manufactured by Nippon Polyurethane Industry Co., Ltd.) 26 parts by mass of carbon black “MA100” (trade name, manufactured by Mitsubishi Chemical Co., Ltd.) as a conductive agent was added, and methyl ethyl ketone was used as a main solvent. The mixture was sufficiently stirred and mixed with an organic solvent having a uniform solid content of 14% by mass. It adjusted so that it might become a solution. The elastic roller is immersed in this coating solution for coating, and then pulled up, dried, and heat-treated at 145 ° C. for 30 minutes, whereby a coating layer having a thickness of about 22 μm (hereinafter referred to as coating layer T). A developing roller 1 was prepared on the outer periphery of the elastic layer. The MD-1 hardness of the elastic layer was 14 °, and the amount extracted with n-hexane was 5.0% by mass.

[Example 2] Developing roller 2
The developing roller 2 was produced in the same manner as in Example 1 except that the rubber component used for the elastic layer was changed to only rubber B and changed to 100 parts by mass. The MD-1 hardness of the elastic layer was 17 °, and the amount extracted with n-hexane was 4.4% by mass.

[Example 3] Developing roller 3
A rubber component used for the elastic layer is a rubber having a viscosity of 340 Pa · s composed of ethylene, propylene, and a copolymer using 6,7-dimethyl-4-ethylidene-1,6-octadiene as the third component [hereinafter, The developing roller 3 was prepared in the same manner as in Example 1 except that the rubber C was changed to 100 parts by mass. The MD-1 hardness of the elastic layer was 25 °, and the amount extracted with n-hexane was 3.8% by mass.

[Embodiment 4] Developing roller 4
Rubber having a viscosity of 800 Pa · s comprising rubber C as a rubber component and a copolymer using rubber C, ethylene, propylene, and 6,7-dimethyl-4-ethylidene-1,6-octadiene as the third component The developing roller 4 was produced in the same manner as in Example 1 except that the blend was blended with [hereinafter referred to as rubber D], 60 parts by weight of rubber C, and 40 parts by weight of rubber D. Here, the viscosity of the rubber blended with 60 parts by mass of rubber C and 40 parts by mass of rubber D was 620 Pa · s. The MD-1 hardness of the elastic layer was 30 °, and the amount extracted with n-hexane was 3.1% by mass.

[Embodiment 5] Developing roller 5
The developing roller 5 was produced in the same manner as in Example 1 except that the rubber component used for the elastic layer was a blend of rubber C and rubber D, the rubber C was 30 parts by mass, and the rubber D was 70 parts by mass. Here, the viscosity of the rubber blended with 30 parts by mass of rubber C and 70 parts by mass of rubber D was 800 Pa · s.
The MD-1 hardness of the elastic layer was 37 °, and the amount extracted with n-hexane was 2.4% by mass.

[Embodiment 6] Developing roller 6
Rubber having a viscosity of 380 Pa · s made of a copolymer using ethylene, propylene, and 7-methyl-6-propyl-4-ethylidene-1,6-octadiene as a third component as the rubber component used for the elastic layer [ Hereinafter, the developing roller 6 was produced in the same manner as in Example 1 except that the rubber E was changed to 100 parts by mass. The MD-1 hardness of the elastic layer was 27 °, and the amount extracted with n-hexane was 4.2% by mass.

[Embodiment 7] Developing roller 7
Rubber having a viscosity of 410 Pa · s made of a copolymer using ethylene, propylene, and 8-methyl-4-ethylidene-1,7-nonadiene as a third component [hereinafter referred to as rubber F] The developing roller 7 was produced in the same manner as in Example 1 except that the amount was changed to 100 parts by mass. The MD-1 hardness of the elastic layer was 29 °, and the amount extracted with n-hexane was 3.6% by mass.

[Eighth Embodiment] Developing Roller 8
The rubber component used for the elastic layer is a blend of rubber C and liquid butadiene rubber (hereinafter referred to as rubber G), except that rubber C is 80 parts by mass and rubber G is 20 parts by mass. Similarly, the developing roller 8 was produced. Here, the viscosity of the rubber blended with 80 parts by mass of rubber C and 20 parts by mass of rubber G was 430 Pa · s. The MD-1 hardness of the elastic layer was 34 °, and the amount extracted with n-hexane was 4.4% by mass.

[Embodiment 9] Developing roller 9
The rubber component used for the elastic layer is 100 parts by mass of rubber C, and as carbon black, # 32 (trade name, manufactured by Mitsubishi Chemical Corporation) (hereinafter referred to as carbon black I) is changed to 40 parts by mass. A developing roller 9 was produced in the same manner as in Example 1. The MD-1 hardness of the elastic layer was 25 °, and the amount extracted with n-hexane was 3.8% by mass.

[Embodiment 10] Developing roller 10
The rubber component used for the elastic layer was changed to 100 parts by mass of rubber C, and the carbon black was changed to 30 parts by weight of Printex 60 (trade name, manufactured by Degussa) (hereinafter referred to as carbon black J). A developing roller 10 was produced in the same manner as in Example 1. The MD-1 hardness of the elastic layer was 24 °, and the amount extracted with n-hexane was 4.0% by mass.

[Embodiment 11] Developing roller 11
As rubber component used for the elastic layer, rubber C is 100 parts by mass, carbon black is # 52 (trade name, manufactured by Mitsubishi Chemical Corporation) [hereinafter referred to as carbon black K] is changed to 45 parts by mass. A developing roller 11 was produced in the same manner as in Example 1. The MD-1 hardness of the elastic layer was 26 °, and the amount extracted with n-hexane was 3.7% by mass.

[Embodiment 12] Developing roller 12
The rubber component used for the elastic layer is 100 parts by mass of rubber C, and Asahi # 70 (trade name, manufactured by Asahi Carbon Co., Ltd.) [hereinafter referred to as carbon black L] is changed to 70 parts by mass as carbon black. A developing roller 12 was prepared in the same manner as in Example 1. The MD-1 hardness of the elastic layer was 38 °, and the amount extracted with n-hexane was 3.5% by mass.

[Embodiment 13] Developing roller 13
The rubber component used for the elastic layer is 100 parts by mass of rubber C, and as carbon black, except that # 45L (trade name, manufactured by Mitsubishi Chemical Corporation) [hereinafter referred to as carbon black M] is changed to 50 parts by mass. A developing roller 13 was produced in the same manner as in Example 1. The MD-1 hardness of the elastic layer was 29 °, and the amount extracted with n-hexane was 3.3% by mass.

[Embodiment 14] Developing roller 14
The rubber component used for the elastic layer is 100 parts by mass of rubber C, and the carbon black is printed except that Printex L6 (trade name, manufactured by Degussa) (hereinafter referred to as carbon black N) is changed to 25 parts by mass. A developing roller 14 was produced in the same manner as in Example 1. The MD-1 hardness of the elastic layer was 24 °, and the amount extracted with n-hexane was 4.0% by mass.
[Embodiment 15] Developing roller 15
As a rubber component used for the elastic body layer, rubber C is 100 parts by mass, and an organic peroxide used as a crosslinking agent is 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane, perhexa 3M. A developing roller 15 was produced in the same manner as in Example 1 except that (trade name, manufactured by NOF Corporation) [hereinafter referred to as cross-linking agent P] was changed to 7.0 parts by weight. The MD-1 hardness of the elastic layer was 24 °, and the amount extracted with n-hexane was 4.6% by mass.

[Embodiment 16] Developing roller 16
The developing roller 15 was produced in the same manner as in Example 1 except that the rubber component used in the elastic layer was 100 parts by mass of rubber C, and triallyl isocyanurate as a co-crosslinking agent was not added. The developing roller 15 corresponds to a member obtained by removing triallyl isocyanurate from the elastic layer of the developing roller 3. The MD-1 hardness of the elastic layer was 22 °, and the amount extracted with n-hexane was 4.9% by mass.

[Embodiment 17] Developing roller 17
The rubber component used for the elastic layer is 100 parts by mass of rubber C, and the organic peroxide used as a crosslinking agent is 2,5-di-methyl-2,5-di (t-butylperoxy) hexyne, perhexine. The developing roller 17 was produced in the same manner as in Example 1 except that 25B (trade name, manufactured by NOF Corporation) (hereinafter referred to as the crosslinking agent R) was changed to 7.5 parts by weight. The MD-1 hardness of the elastic layer was 25 °, and the amount extracted with n-hexane was 3.7% by mass.

[Embodiment 18] Developing roller 18
The same raw material compound as in Example 8 was prepared, and dispersible sulfur “Sulfax 200S” (trade name, manufactured by Tsurumi Chemical Co., Ltd., purity 99.5%) with respect to the rubber component (100 parts by mass of rubber A) 1 .6 parts by mass, 1.2 parts by mass of di-2-benzothiazolyl disulfide “Noxeller DM” (trade name, manufactured by Ouchi Shinsei Chemical), dipentamethylene thiuram tetrasulfide “Noxeller TRA” (trade name, large Inner Emerging Chemical Co., Ltd.) 1 part by mass, tetramethylthiuram monosulfide “Noxeller TS” (trade name, manufactured by Ouchi Emerging Chemicals Co., Ltd.) 0.8 part by mass, and cooled to 20 ° C. Kneading for 10 minutes gave an elastic layer compound. A developing roller 17 was produced in the same manner as in Example 1 except that this elastic compound was used. The MD-1 hardness of the elastic layer was 36 °, and the amount extracted with n-hexane was 4.6% by mass.

[Embodiment 19] Developing roller 19
The rubber component used for the elastic layer is 100 parts by mass of rubber C, and the coating layer is carbon black “MA11” as a conductive agent with respect to 100 parts by mass of the alcohol-soluble polyamide resin “Amilan CM8000” (trade name, manufactured by Toray Industries, Inc.). (Trade name, manufactured by Mitsubishi Chemical Co., Ltd.) was added in an amount of 22 parts by mass, and methanol was used as a main solvent, and the mixture was sufficiently stirred to prepare an organic solvent mixed solution having a uniform solid content of 18%. The elastic roller is immersed in this coating solution for coating, and then pulled up, dried, and heat-treated at 85 ° C. for 30 minutes, thereby elastically forming a coating layer of about 15 μm (hereinafter referred to as coating layer U). A developing roller 19 was produced in the same manner as in Example 1 except that it was provided on the outer periphery of the body layer. In addition, the amount of MD-1 hardness and n-hexane extracted from the elastic layer were 25 ° and 3.8% by mass, respectively, as in the developing roller 3.

[Embodiment 20] Developing roller 20
As a rubber component used for the elastic layer, 100 parts by mass of rubber C is used, and as a coating layer, carbon black is used as a conductive agent with respect to 100 parts by mass of a polyol “Nippolan 5230” (trade name, manufactured by Nippon Polyurethane Industry Co., Ltd.). 22 parts by mass of “MA11” (trade name, manufactured by Mitsubishi Chemical Co., Ltd.) was added, and methyl ethyl ketone was used as a main solvent, and the mixture was sufficiently stirred to prepare a mixed organic solvent solution having a uniform solid content of 12% by mass. A coating layer having a thickness of about 20 μm (hereinafter referred to as coating layer V) is obtained by immersing and coating the elastic roller in this coating solution, and then pulling it up and drying, followed by heat treatment at 130 ° C. for 30 minutes. The developing roller 20 was produced in the same manner as in Example 1 except that was provided on the outer periphery of the elastic layer. In addition, the amount of MD-1 hardness and n-hexane extracted from the elastic layer were 25 ° and 3.8% by mass, respectively, as in the developing roller 3.

[Example 21] Developing roller 21
As a rubber component used for the elastic body layer, 100 parts by mass of rubber C was used, and an elastic roller having only the elastic body layer was produced in the same manner as in Example 1. That is, an elastic roller for the developing roller 3 was prepared. The developing roller 21 was used as it was without providing a coating layer on the elastic roller. The amount of MD-1 hardness and n-hexane extracted from the elastic layer was 25 ° and 3.8% by mass, respectively, as in the developing roller 3.

[Comparative Example 1] Developing roller 22
The developing roller 22 was produced in the same manner as in Example 1 except that the rubber component used for the elastic layer was a blend of rubber A and rubber B, and 70 parts by weight of rubber A and 30 parts by weight of rubber B were used. Here, the viscosity of the rubber blended with 70 parts by mass of rubber A and 30 parts by mass of rubber B was 70 Pa · s.
The MD-1 hardness of the elastic layer was 12 °, and the amount extracted with n-hexane was 5.8% by mass.

[Comparative Example 2] Developing roller 23
The developing roller 23 was produced in the same manner as in Example 1 except that the rubber component used for the elastic layer was 100 parts by mass of the rubber D. The MD-1 hardness of the elastic layer was 45 °, and the amount extracted with n-hexane was 2.1% by mass.

[Comparative Example 3] Developing roller 24
The developing roller 24 was produced in the same manner as in Example 1 except that the rubber component used for the elastic layer was 100 parts by mass of the rubber G. That is, the developing roller 24 does not contain rubber made of ethylene, propylene, and a third component copolymer in the elastic layer. The MD-1 hardness of the elastic layer was 36 °, and the amount extracted with n-hexane was 8.4% by mass.

[Comparative Example 4] Developing roller 25
The same raw material compound as in Example 3 was prepared, and dispersible sulfur “Sulfax 200S” (trade name, manufactured by Tsurumi Chemical Co., Ltd., purity 99.5%) with respect to the rubber component (100 parts by mass of rubber A) 1 .6 parts by mass, 1.2 parts by mass of di-2-benzothiazolyl disulfide “Noxeller DM” (trade name, manufactured by Ouchi Shinsei Chemical), dipentamethylene thiuram tetrasulfide “Noxeller TRA” (trade name, large Inner Emerging Chemical Co., Ltd.) 1 part by mass, tetramethylthiuram monosulfide “Noxeller TS” (trade name, manufactured by Ouchi Emerging Chemicals Co., Ltd.) 0.8 part by mass, and cooled to 20 ° C. Kneading for 10 minutes gave an elastic layer compound. A developing roller 25 was produced in the same manner as in Example 1 except that this elastic compound was used. The MD-1 hardness of the elastic layer was 24 °, and the amount extracted with n-hexane was 7.6% by mass.

[Comparative Example 5] Developing roller 26
NBR “Nipol 1043” (trade name, manufactured by Nippon Zeon Co., Ltd.) 100 parts by mass, zinc oxide 5 parts by mass, stearic acid 2 parts by mass, calcium carbonate 30 parts by mass, 2-mercaptobenzimidazole (MB) 0.5 parts by mass, 50 parts by mass of carbon black H and 80 parts by mass of a polyester plasticizer “Polysizer W-340” (trade name, manufactured by Dainippon Ink Co., Ltd.) were kneaded for 10 minutes in a closed mixer adjusted to 50 ° C. A compound was prepared. Furthermore, with respect to the rubber content (100 parts by mass of rubber A), “Perhexine 25B-40” (trade name, product name manufactured by NOF Corporation; 40% product), 9.0 parts by mass, triallyl isocyanurate “TAIC” (product) (Name, Nippon Kasei Co., Ltd.) 4 parts by mass was added and kneaded for 10 minutes in a two-roll machine cooled to 20 ° C. to obtain a compound for an elastic layer. NBR “Nipol 1043” is in a solid state at room temperature and has almost no fluidity.

This elastic compound is formed into a tube shape by extrusion molding, primary vulcanization is performed by steam vulcanization at 130 ° C. for 30 minutes, further secondary vulcanization is performed by electric furnace at 140 ° C. for 30 minutes, and a rubber tube is formed. Obtained. After this tube was cut, a SUS metal core (diameter 8 mm) with nickel plating applied as a shaft core body was press-fitted, and the surface was polished to obtain an elastic roller having a diameter of 16 mm.
In the same manner as in Example 1, the developing roller 26 was produced by forming the coating layer T on the outer periphery of the elastic roller. The MD-1 hardness of the elastic layer was 57 °, and the amount extracted with n-hexane was 21.8% by mass.

[Comparative Example 6] Developing roller 27
The developing roller 27 is the same as Comparative Example 5 except that the amount of the polyester plasticizer “Polysizer W-340” (trade name, manufactured by Dainippon Ink Co., Ltd.) added as the raw material compound is changed to 40 parts by mass. Was made. The MD-1 hardness of the elastic layer was 71 °, and the amount extracted with n-hexane was 14.6% by mass.

[Comparative Example 7] Developing roller 28
In order to prepare the elastic layer compound, 100 parts by mass of EPDM “Esprene 201” (trade name, manufactured by Sumitomo Chemical Co., Ltd.), 5 parts by mass of zinc oxide, 1.5 parts by mass of stearic acid, 30 parts by mass of calcium carbonate, 2 -0.5 parts by mass of mercaptobenzimidazole (MB), 50 parts by mass of carbon black H, and 40 parts by mass of a hydrocarbon plasticizer “P-300” (trade name, manufactured by Shell Chemical Co., Ltd.) were adjusted to 50 ° C. A raw material compound was prepared by kneading for 10 minutes in a closed mixer. Furthermore, with respect to the rubber content (100 parts by mass of rubber A), 6.5 parts by mass of “Perhexine 25B-40” (trade name, product name manufactured by NOF Corporation; 40% by mass), triallyl isocyanurate “TAIC” ( (Product name, manufactured by Nippon Kasei Kogyo Co., Ltd.) 2.5 parts by mass was added and kneaded for 10 minutes in a two-roll machine cooled to 20 ° C. to obtain a compound for an elastic layer. EPDM “Esprene 201” is in a solid state at room temperature and does not correspond to the liquid rubber of the present invention.
A developing roller 28 was produced in the same manner as in Comparative Example 26 except that this elastic compound was used. The MD-1 hardness of the elastic layer was 66 °, and the amount extracted with n-hexane was 16.7% by mass.

  Table 1 shows the chemical names of the third components of the rubbers A to G (in the case of rubber made of a copolymer of ethylene, propylene, and the third component) and the viscosity. The rubber G is a butadiene rubber and there is no equivalent to the third component. In Examples 1, 4, 5, 8, 18, and Comparative Example 1, two types of rubber are blended and used.

  Table 2 shows the DBP absorption (D), volatile content (V), nitrogen specific surface area (N), and V / N value of carbon blacks H to N.

The chemical names (in the case of organic peroxides) of the crosslinking agents P to S are shown in Table 3.
The cross-linking agent S uses dispersible sulfur and is not a courageous peroxide.

  Table 4 shows the main components of the coating layers T, U, and V.

  Table 5 shows combinations of elastic layers and coating layers of the developing rollers 1 to 28 corresponding to Examples 1 to 21 and Comparative Examples 1 to 7.

  The following evaluations were performed on the created developing rollers 1 to 28.

[Characteristic evaluation]
<Hardness (nip width)>
The nip width when using a 300 mm long semi-cylindrical glass with a curved surface with a diameter of 30 mm and applying a load of 500 g (1 kg total) on one side to the shaft core of the developing roller and press-contacting the curved surface with a diameter of 30 mm The nip state was observed with a microscope from the opposite side and evaluated. The developing roller to be measured was left in an environment of 25 ° C. and a relative humidity of 50% RH for 8 hours or more, and then measured in an environment of 25 ° C. and a relative humidity of 50% RH.
A: Nip width of 0.8 mm or more at the developing roller central part B: Nip width of 0.7 mm or more and less than 0.8 mm at the developing roller center part C: Nip width of 0.5 mm or more and less than 0.7 mm at the developing roller center part Width D: Nip width of less than 0.5 mm at the center of the developing roller.

<Shape (dimensional accuracy)>
The shape (dimensional accuracy) of the developing roller was evaluated as follows.
Outer diameter measured at every 1 ° on each face (10 places in total) of the cut surface by dividing the length of the elastic rubber layer in the axial direction into 9 parts, excluding 5% of each axial end of the elastic rubber layer. Judgment was made based on the difference between the average maximum and minimum values. The outer diameter was measured by rotating the laser measuring machine by 1 ° in the circumferential direction, and the measured values of the total 360 were arithmetically averaged to obtain the average outer diameter value at that point. The same mold is used for injecting and molding liquid rubber. As a result of repeated measurements, the repeat measurement accuracy at the same location is all within 3 μm after 10 measurements. In addition, the repeatability between the molded rollers is also sufficiently stable to verify the effect of the present invention, and for each of the development rollers of Examples and Comparative Examples, 10 are measured and evaluated by arithmetic mean. did. The developing roller to be measured was left in an environment of 25 ° C. and a relative humidity of 50% RH for 8 hours or more, and then measured in an environment of 25 ° C. and a relative humidity of 50% RH.
A: The difference between the maximum value and the minimum value is 50 μm or less (thing that does not require polishing)
B: The difference between the maximum value and the minimum value is more than 50μm and less than 100μm or surface polishing is performed, the difference between the maximum value and the minimum value is less than 100μm C: The difference between the maximum value and the minimum value is 100μm Exceeding 150 μm or less In Comparative Examples 5, 6, and 7, the shape is adjusted by polishing the surface of the elastic layer.

<Bleed>
A developing roller is incorporated in the cartridge and left in an environmental tester at room temperature of 35 ° C. and relative humidity of 85% RH for 14 days. Then, the cartridge is disassembled in an environment of room temperature of 25 ° C. and relative humidity of 50% RH, and the surface of the photoconductor The presence or absence of adhesion to the surface and the presence or absence of bleeding on the surface of the developing roller were visually observed.
A: There is no adhesion on the surface of the photoreceptor, and there is no bleed on the surface of the developing roller.
B: There is no adhesion on the surface of the photoreceptor, but slight bleeding is observed on the surface of the developing roller.
C: Although there is no adhesion on the surface of the photoreceptor, bleeding is observed on the surface of the developing roller.
D: Adhesion on the surface of the photoreceptor is observed.

  As an image forming apparatus, a laser printer “Satera LBP5500” (trade name, manufactured by Canon Inc.) was prepared. This LBP 5500 (trade name) is a tandem type color printer that includes four developer color cartridges, each of which is provided with image writing means (laser beam) and a transfer belt. The standard image creation capability is 17 sheets / minute for A4 size.

  The cartridge includes a photosensitive drum, and includes a charging roller as a charging unit (a Kapton (trademark) sheet is provided in contact with the photosensitive drum for cleaning the charging roller) and a developing roller as a developing unit. Further, a supply roller is provided for supplying the developer onto the developing roller, scraping off the returned developer that has not been used for forming the developer image remaining on the developing roller, and frictionally charging the developer. A developer regulating blade is provided in contact with the developing roller to keep the developer amount constant and impart triboelectric charging when it is carried (corresponding to a one-component contact development system). The developing roller is in contact with the photosensitive drum.

  Further, the cartridge is provided with a cleaning blade that comes into contact with the photosensitive drum and wipes off developer remaining on the photosensitive drum and transfer material debris so as to remove the charge remaining on the photosensitive drum before charging by the charging roller. Pre-exposure means is provided.

  The apparatus was processed so that the output speed of LBP5500 (trade name) was increased to 22 sheets / minute of A4 paper, and the developing rollers 1 to 28 produced in this example and the comparative example were incorporated as developing rollers of the cyan color cartridge, respectively. . Further, each of the magenta, yellow, and black cartridges was placed in each station with the developer removed and the developer remaining amount detection mechanism disabled.

[Image evaluation]
Using the image forming apparatus modified as described above, LETTER-sized plain paper “XEROX 4024 paper” (product name) is output as a transfer material, the 10th sheet is an entire solid image, and the 11th sheet is a halftone solid image. It was. The first to tenth sheets output full-tone halftone solid images. All outputs were performed in an environment of 25 ° C. and a relative humidity of 50% RH.

<Initial concentration>
Using a reflection densitometer RD918 (manufactured by Macbeth) for a solid image (tenth image) whose entire image area is uniform, measure the density of the solid black portion when solid printing is performed, and average the image density. It was.
A: Average value is 1.20 or more B: Average value is 1.15 or more and less than 1.20 C: Average value is 1.10 or more and less than 1.20 D: Average value is less than 1.10.

<Initial density unevenness>
The shade unevenness appearing in the image obtained by the solid image (10th image) and the halftone image (11th image) where the entire image area is uniform is visually observed by five inspectors, and the following criteria are evaluated. I got it. Then, the evaluation results of five inspectors were ranked, and the median value (third evaluation) was set as the evaluation for the sample.
A: The shading unevenness is not conspicuous in both the solid image and the halftone image and is good.
B: Light and shade unevenness is slightly noticeable in a solid image but at a level that does not cause a problem.
C: Light and dark unevenness is slightly seen in both solid images and halftone images, but at a level with no problem.

  D: Density unevenness is observed in both solid images and halftone images. In solid images, white spots are conspicuous due to insufficient nip width in the center, and the impression is poor.

<Contact part image>
As the developing roller of the cyan color cartridge, after incorporating the developing rollers 1 to 28 produced in this example and the comparative example, each cartridge is placed in an environment of 25 ° C. ± 2 ° C. and a relative humidity of 50% RH ± 5%. The image was output after being left for a day. Inspects stripe-shaped shading unevenness in the direction perpendicular to the image printing direction of the developing roller cycle appearing in the image obtained with the solid image (10th sheet) and halftone image (11th sheet) where the entire image area is uniform It was observed by the visual observation of five members, and the following criteria were evaluated. Then, the evaluation results of five inspectors were ranked, and the median value (third evaluation) was set as the evaluation for the sample. The stripe-shaped shading unevenness is a portion corresponding to a contact portion between the regulating blade 24 and the surface of the developing roller 1.
A: Striped shading unevenness is inconspicuous and good for both solid images and halftone images.
B: Streaky shading unevenness is slightly noticeable in a solid image but at a level that does not cause a problem, and is not noticeable in a halftone image and is good.
C: A stripe-like shading unevenness is slightly seen in both the solid image and the halftone image, but there is no problem.

  D: Streaky shading unevenness is observed in both solid images and halftone images, and the impression is bad.

<Comprehensive evaluation>
The results of the above evaluations (hardness, shape, bleed, initial density, initial density unevenness, contact part image) were integrated and evaluated comprehensively according to the following criteria.
A: Six items are A. B: Shape, initial density, contact part image is B or more, hardness, bleed, initial density unevenness is C or more C: All six items are C or more D: Any Table 6 shows the results of evaluation based on the above criteria.
As shown in Table 6, Examples 1 to 21 gave good results, and Examples 3, 4, 7, 9, and 17 gave particularly good results.

It is a figure which shows typically an example of the whole structure of the developing roller of this invention. It is sectional drawing of FIG. 1 which shows typically the two-layer structure of a roller layer in the developing roller of this invention. It is explanatory drawing of the image forming apparatus using the developing device of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Developing roller 2 ... Developing apparatus 3 ... Image forming apparatus
11 ... Shaft core
12 ... Elastic layer (base layer)
13… Coating layer (surface layer)
21 ... Latent image carrier (photosensitive drum)
22 ... Developer application member
23 ... Developer (toner)
24 ... Regulator blade
25 ... Laser light
26 ... Charging member
27 ... Waste developer container (waste toner container)
28 ... Cleaning member
29 ・ ・ ・ Fixing device
30 ... Drive roller
31 ... Transfer roller
32 ... Bias power supply
33 ... Tension roller
34 ... Transfer conveyor belt
35 ... driven roller
36 ・ ・ ・ Transfer paper
37 ・ ・ ・ Feeding roller
38 ... Suction roller

Claims (12)

A developing roller having at least an elastic layer formed on an outer peripheral surface of a shaft core, wherein the elastic layer contains a rubber made of a copolymer of ethylene, propylene, and a third component, and the MD of the elastic layer A developing roller having a hardness of −1 in the range of 5 ° to 38 °, and an extraction amount of the elastic layer with n-hexane of 0.0% by mass or more and 5.0% by mass or less. A liquid rubber having a viscosity of 100 Pa · s or more and 800 Pa · s or less is used as a copolymer of the third component selected from ethylene, propylene, and a diene or polyene contained in the elastic body layer. The developing roller according to claim 1, wherein the rubber is in a proportion of 80% by mass or more and 100% by mass or less in the rubber component of the elastic layer. The developing roller according to claim 1, wherein the third component has a structure having a vinyl group. The developing roller according to claim 1, wherein the third component contains a structure represented by chemical formula (I) or a structure derived therefrom.

Chemical formula (I)
In the formula (I), n is an integer of 1 to 5, R 1 is an alkyl group having 1 to 5 carbon atoms, and R 2 and R 3 are each independently a hydrogen atom or 1 to 5 carbon atoms. It is an alkyl group. 5. The developing roller according to claim 1, comprising carbon black having a DBP absorption amount of 60 ml / 100 g or more and 110 ml / 100 g or less as a means for making the elastic layer conductive. . The developing roller according to claim 5, wherein a ratio of volatile matter / nitrogen specific surface area of the carbon black is 1.4 × 10 ⁻⁴ g / m ² or less. The developing roller according to claim 1, wherein the elastic body layer is crosslinked with an organic peroxide crosslinking agent. The organic peroxide crosslinking agent is 2,5-di-methyl-2,5-di (t-butylperoxy) hexane, 2,5-di-methyl-2,5-di (t-butylperoxy). 8. The developing roller according to claim 7, wherein at least one kind of hexyne is selected and triallyl isocyanurate is added. A developing roller having a resin layer coated on the outer periphery of the elastic layer according to claim 2. The elastic body layer is formed by injecting a liquid rubber material into a cavity of a mold heated to a predetermined temperature from an injection hole of an injection nozzle and crosslinking the liquid rubber material in the cavity. A method for manufacturing a developing roller according to claim 1. A developing roller that carries a developer in a state of being opposed to the latent image carrier that carries the latent image is provided, and the developing roller applies the developer to the latent image carrier to visualize the latent image as a developer image. The developing device according to claim 1, wherein the developing device is any one of the developing rollers according to claim 1. A latent image carrier on which an electrostatic latent image is formed by electrophotography, a charging device for charging the latent image carrier with a charge amount necessary for forming the electrostatic latent image, An image having an electrostatic latent image forming device for forming a latent image, a developing device for attaching a developer to the electrostatic latent image for visualization, and a transfer device for transferring an image made of the developer onto transfer paper A forming device,
The developing device holds the developer carried on the surface of the latent image carrier on which the electrostatic latent image is formed in a state where the developer is carried in a state of being opposed to or pressed against the surface of the latent image carrier. A developing roller for supplying an electrostatic latent image to visualize the electrostatic latent image, wherein the developing roller is the developing roller according to claim 1. Image forming apparatus.

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