JP4827322B2 - Method for manufacturing roller for image forming apparatus - Google Patents

Description

【００２３】
表１において、符号＊を付したローラは、研削取り代とトラバース速度が本発明の範囲内のものであり、外観が良好であり、研削時間も短いものであるが、研削取り代及び／又はトラバース速度が本発明の範囲外であるものは、外観と研削時間の両方を満足するものではないことがわかる。
次に、研削取り代2.０ｍｍ、トラバース速度８００ｍｍ／分で製造したローラを、図１に示す画像形成装置に転写ローラとして組み込んだ。なお、転写ローラの両端には、直径６ｍｍの芯金が突出しており、該突出部はばねによる両端各４．９Ｎの押圧力によって画像形成体に押圧されている。この転写ローラの両端のニップ幅は２．０ｍｍ、中央のニップ幅は２．０ｍｍであった。また、温度、湿度がそれぞれ１５℃、１０％の環境でグレースケール、黒ベタ、白ベタ画像を印刷させたところ良好な画像が得られた。
【００２４】
【発明の効果】
本発明の方法によれば、擬紡錘型弾性層を有し、帯電ローラ、現像ローラ、転写ローラ、トナー供給ローラ、クリーニングローラなどして用いられる画像形成装置用ローラを、通常の円柱型ローラの製造に用いられる端縁部垂直型の平形砥石を用いて効率よく製造することができる。
【図面の簡単な説明】
【図１】 電子写真方式による画像形成装置の一例を示す概要図である。
【図２】 端縁部垂直型の平形砥石を用い、弾性素材を研削加工して、擬紡錘型ローラを製造する手順の一例を示す側面説明図である。
【図３】 本発明の方法で得られる画像形成装置用ローラの一例の側面図である。
【符号の説明】
１ 画像形成体
２ 現像ローラ
３ トナー供給ローラ
４ 層規制ブレード
５ 転写ローラ
６ クリーニングローラ
７ 帯電ローラ
８ 転写材[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a roller for an image forming apparatus. More specifically, the present invention relates to an image forming apparatus roller having a pseudo-spindle type elastic body layer and used as a charging roller, a developing roller, a transfer roller, a toner supply roller, a cleaning roller, etc. The present invention relates to an industrially advantageous method for producing efficiently using a flat grindstone of a vertical edge portion used in the production of the above.
[0002]
[Prior art]
In recent years, with the advancement of electrophotographic technology, image forming apparatuses such as dry electrophotographic apparatuses include polymer members as parts for parts used for charging, development, transfer, toner supply, cleaning, etc. In general, it is used in the form of a roller having elasticity such as a charging roller, a developing roller, a transfer roller, a toner supply roller, and a cleaning roller. In processes such as charging and transfer with an elastic roller, this polymer member has advantages such as obtaining the required charge potential of the image forming body and the amount of toner transfer with a lower power supply voltage compared to conventional corotron chargers. is there.
The polymer member used for these purposes is usually a polymer elastomer or foam such as rubber or polyurethane, and these are low in hardness and contaminate the image forming body or transfer material. In many cases, it is required to have a predetermined resistance value in a medium resistance region of 10 ⁴ to 10 ¹⁰ Ω.
[0003]
FIG. 1 is a schematic diagram showing an example of an electrophotographic image forming apparatus, which is a toner supply roller (toner supply member) 3 and an image forming body (electrostatic latent image carrier) holding a latent electrostatic latent image. The developing roller 2 is disposed between the image forming body 1 and the outer peripheral surface thereof in contact with or close to the surface of the image forming body 1, and the image forming body 1 is transferred to the image forming body 1 via a transfer material 8 such as paper. 5 shows a structure in which 5 is abutted. By rotating the toner supply roller 3, the developing roller 2, and the image forming body 1 in the direction of the arrow, the toner is supplied to the surface of the developing roller 2 by the toner supply roller 3, and a uniform thin layer is prepared by the layer regulating blade 4. After that, it adheres to the latent image on the image forming body 1 and the latent image is visualized. Then, by generating an electric field between the image forming body 1 and the transfer roller 5, the toner image on the image forming body 1 is transferred to the transfer material 8. A cleaning roller 6 removes toner remaining on the surface of the image forming body 1 after the transfer. Reference numeral 7 denotes a charging roller.
Each of these rollers is usually used in pressure contact with the target member. As a means for the pressure contact, generally, a method of pressing both end shaft portions of the roller in the direction of the target with a spring or the like is employed. Yes. However, according to such a pressure contact method, when the roller has a cylindrical shape, the pressure contact force to the object is different between the vicinity of both ends of the roller and the center portion, and both end portions are larger than the center portion. . Since the roller is formed of an elastic material, for example, in the transfer roller, the nip width (length in the running direction of the transfer material) is also about 2 to 4 times larger at both end portions than the center portion. Prone.
[0004]
Therefore, when each roller is operated in such a state, the press contact force and the nip width in the roller are not uniform, which may cause an image defect. For example, in the case of a transfer roller, the nip width is small at the central portion of the transfer material, and as a result, the transfer material is not sufficiently exposed to the transfer electric field, which may cause transfer failure and excessive transfer pressure. If this is the case, a void may occur in the character image.
Therefore, in order to solve such a problem, a crown type transfer roller has been proposed in which the central portion is made larger than the both end portions by less than 5% (JP-A-4-22980). . However, when manufacturing such a shape by grinding an elastic material with a grindstone, the edge type vertical grindstone normally used in the manufacture of cylindrical rollers cannot be used. Since a part-R type flat grindstone is used, when producing a cylindrical roller and a crown-type roller on the same production line, the grindstone must be replaced each time, which is troublesome. Moreover, when manufacturing by another line, a new manufacturing line must be provided, and it cannot avoid being expensive.
[0005]
FIG. 2 is an explanatory side view illustrating an example of a procedure for manufacturing a pseudo-spindle type roller by grinding an elastic material using a vertical edge grindstone. This roller is provided with a quasi-spindle elastic body layer 12 on the outer periphery of the rotation center shaft 11, and the quasi-spindle elastic body layer 12 has a central cylindrical portion 13 and the same shape connected to both ends thereof. Are connected to both ends of the truncated cone portions 14 and 14 ′, respectively, and cylindrical portions 15 and 15 ′ having the same shape with a smaller diameter than the central cylindrical portion 13 are integrated. It has the structure. As shown in the figure, first, the cylindrical portion 15 is ground by a flat edge grindstone 16 having a vertical edge, and then the grindstone 16 is moved from (a) to (b) to grind the truncated cone portion 14. To do. Next, after moving the grindstone 16 from (b) to (c) and grinding the central cylindrical portion 13, the grindstone 16 is moved from (c) to (d), and the truncated cone portion 14 'is ground. The cylindrical portion 15 'is ground. In addition, P part of the grindstone 16 is a contact part with the elastic raw material of a workpiece, and grinding is performed in this part.
The above grinding process is a method of fixing the elastic material of the work material and moving the grindstone in the x-axis direction and the y-axis direction shown in FIG. The elastic material can be ground and moved in the direction of the rotation axis.
These grinding processes are performed by rotating the grindstone at a high speed and moving the grindstone or the work material in the direction of the rotation axis of the work material while rotating the work material at a low speed.
However, in such a grinding process, spiral fringe patterns, discoloration, and the like are likely to occur in the truncated cone part 14 and the truncated cone part 14 ', which causes a problem in appearance.
[0006]
[Problems to be solved by the invention]
Under such circumstances, the present invention provides a roller for an image forming apparatus, which has a good appearance, a uniform pressure contact force and a nip width with respect to an object over the entire roller, and gives a good image. An object of the present invention is to provide an industrially advantageous method of efficiently producing using a vertical edge grindstone generally used for production.
[0007]
[Means for Solving the Problems]
As a result of intensive studies to achieve the above object, the inventors of the present invention have made a pseudo spindle type elastic body by optimizing the machining allowance during the finish grinding of the traverse speed of a flat grindstone with a vertical edge. It has been found that a roller having a layer can be easily produced. The present invention has been completed based on such findings.
That is, the present invention is a method of manufacturing a roller having a pseudo-spindle type elastic body layer on the outer periphery of a rotation center shaft by grinding an elastic material with a traverse polishing machine using a flat grindstone with a vertical edge. Grinding under conditions of 1.7 ≦ a ≦ 4.0 and 500 ≦ b ≦ 900, where a (mm) is the grinding allowance and b (mm / min) is the traversing speed of the flat grinding wheel. An image forming apparatus roller manufacturing method is provided. The present invention also provides an image forming apparatus including a roller manufactured by this manufacturing method.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The method for manufacturing a roller for an image forming apparatus according to the present invention uses a flat grindstone and grinds an elastic material, whereby a roller having a pseudo-spindle elastic body layer on the outer periphery of the rotation center axis (hereinafter referred to as a pseudo-spindle roller) 2) in the method shown in FIG. 2, when the grinding allowance is a (mm) and the traversing speed of the flat grindstone is b (mm / min), Grinding is performed under the conditions of 1.7 ≦ a ≦ 4.0 and 500 ≦ b ≦ 900. If the machining allowance is less than 1.7 mm, a spiral stripe pattern is generated in the truncated cone part, and there is a problem in appearance (part indicated by 14 'in FIG. 2). When the machining allowance exceeds 4.0 mm, the amount of industrial waste increases due to an increase in shavings from grinding. Further, if the traverse speed of the grindstone is less than 500 mm / min, it takes a long time for grinding. Therefore, the cost of the roller increases, and if the traverse speed of the grindstone exceeds 900 mm / min, the entire roller is spiraled. A striped pattern is generated and there is a problem in appearance.
Since the roller manufactured by the method of the present invention has a difference in outer diameter between the central portion and the end portion, the movement amount of the grindstone in the y-axis direction is adjusted by a grinding program based on the traverse speed and the machining allowance.
FIG. 3 is a side view of an example of a roller for an image forming apparatus obtained by the method of the present invention. Details of each part are the same as those described in FIG. In the above roller, the outer diameter of the central cylindrical portion 12 is preferably 0.1 to 5%, more preferably 0.3 to 3%, particularly preferably 0. 0% with respect to the outer diameter of the cylindrical portions 15 and 15 'on both ends. A large value within the range of 5 to 2% is desirable from the viewpoint of performance.
[0009]
Further, the ratio of the lengths of the central cylindrical portion 13, both truncated cone portions 14, 14 ′, and both end cylindrical portions 15, 15 ′ of the roller is preferably 1: 1.5 to 5.0: 0.8 to 3 It is desirable from the viewpoint of performance to be in the range of 0.0.
The pseudo-spindle type roller having such a shape can obtain a uniform pressure contact force and a nip width with respect to an object, like the crown type roller, and is a roller for an image forming apparatus, specifically, a charging roller, a developing roller, It can be used as a transfer roller, a toner supply roller, a cleaning roller, etc., and can give a good image.
[0010]
The pseudo-spindle type roller of the present invention is particularly advantageous when applied as a transfer roller among the above-mentioned rollers. In addition, when the roller of the present invention is applied to each of the above rollers, a conductive elastic layer is usually used as the elastic layer.
In the method of the present invention, the pseudo-spindle type roller is manufactured by grinding an elastic material using a flat grindstone with a vertical edge.
The edge type vertical type grindstone is a grindstone used in the production of a normal cylindrical roller. For example, in a normal grindstone using a vitrified binder, the shape defined by JIS is flat (or No. 1). ) And the edge has an A shape. By the way, the edge type R-type flat grinding wheel used for the production of the crown type roller has a flat shape (or No. 1) as defined by JIS, and the edge portion has an F shape. .
[0011]
There is no restriction | limiting in particular as a material of the said elastic body layer, It can select from the well-known thing as a roller for image forming apparatuses, and can use it suitably. Examples of such materials include polyurethane, ethylene-propylene-diene rubber (EPDM), ethylene-propylene rubber (EPR), natural rubber, butyl rubber, nitrile rubber, polyisoprene rubber, polybutadiene rubber, silicone rubber, styrene-butadiene rubber, Mention may be made of elastomers such as chloroprene rubber and acrylic rubber and foams thereof.
Among these, polyurethane foam is preferable, and when a conductive elastic body layer is required, conductive polyurethane foam is preferably used. Such a polyurethane foam can be produced by, for example, subjecting a polyurethane molding material to foaming and curing using a combination of an inert gas and mechanical stirring.
[0012]
In this method, a polyurethane molding material containing a polyol component, a polyisocyanate component, a conductivity imparting agent, a foam stabilizer, a urethane reaction catalyst, and the like that are used as desired is used.
Examples of the polyol component used in the polyurethane molding material include water, propylene glycol, ethylene glycol, glycerin, trimethylolpropane, hexanetriol, triethanolamine, diglycerin, pentaerythritol, ethylenediamine, methylglycogit, aromatic diamine, Addition polymerization of alkylene oxides such as eletin oxide and propylene oxide starting from sorbitol, sucrose, phosphoric acid, etc., polymer polyol modified with polytetramethylene ether glycol, acrylonitrile, styrene, etc., polyol with melamine addition to polyol Polyester polyol obtained by condensing an acid component such as adipic acid and a glycol component such as ethylene glycol, ε-caprolacta Polyester polyols obtained by ring-opening polymerization, polycarbonate diols, diols such as butanediol, triols and their derivatives such as trimethylolpropane.
[0013]
Of these polyol components, polyether polyols are preferred, and polyether polyols and polytetramethylene ether glycols obtained by addition polymerization of alkylene oxides are particularly cured and cured by the combined use of introduction of inert gas and mechanical stirring. In this case, the cell diameter is stable, which is preferable. Examples of the polyether polyol obtained by addition polymerization of the above alkylene oxide include, for example, a polyether obtained by adding ethylene oxide and propylene oxide using water, propylene glycol, ethylene glycol, glycerin, trimethylolpropane, hexanetriol, or the like as a starting material. A polyol can be preferably mentioned. These polyol components may be used alone or in combination of two or more.
[0014]
Examples of the polyisocyanate component used in the polyurethane molding material include various aromatic polyisocyanate compounds such as diphenylmethane diisocyanate and tolylene diisocyanate or derivatives thereof, various aliphatic polyisocyanate compounds such as hexamethylene diisocyanate or derivatives thereof, and isophorone diisocyanate. And alicyclic polyisocyanate compounds or derivatives thereof. Among these polyisocyanate compounds, various aromatic polyisocyanate compounds and derivatives thereof are particularly preferable because the cell diameter is stabilized when foamed and cured by the combined use of introduction of an inert gas and mechanical stirring. Any of the polyisocyanate compounds can be used as a derivative, such as a urethane-modified product modified with a polyol, a dimer formed by uretidione, an isocyanurate-modified product, a carbodiimide / uretonimine-modified product, an allophanate-modified product, a urea-modified product, and a burette. Modified products and the like are used, and urethane modified products and carbodiimide / uretonimine modified products are particularly preferable. These polyisocyanate components may be used alone or in combination of two or more.
The polyol component and the polyisocyanate component are advantageously used in such a ratio that the NCO group / OH group molar ratio is in the range of 0.9 to 1.5, preferably 1.0 to 1.2.
[0015]
In addition, as the conductivity imparting agent, a carbon conductive agent, an ionic conductive agent, or the like can be used. Examples of the carbon conductive agent include gas black such as ketjen black and acetylene black, oil furnace black including ink black, thermal black, channel black, and lamp black. Examples of ionic conductive agents include dodecyltrimethylammonium such as tetraethylammonium, tetrabutylammonium, and lauryltrimethylammonium, octadecyltrimethylammonium such as stearyltrimethylammonium, hexadecyltrimethylammonium, benzyltrimethylammonium, and modified aliphatic dimethylethylammonium. Ammonium salts such as chlorate, chlorate, hydrochloride, bromate, iodate, borofluoride, sulfate, alkyl sulfate, carboxylate, sulfonate: lithium, sodium, calcium, Perchlorate, chlorate, hydrochloride, bromate, iodate, borofluoride, trifluoromethyl sulfate, sulfo of alkali metal or alkaline earth metal such as magnesium Such as salts, and the like. Among these, quaternary ammonium salts of alkylsulfuric acid and quaternary ammonium salts of polybasic carboxylic acids are particularly preferable because of a small increase in resistance during continuous energization.
[0016]
These conductive agents may be used alone or in combination of two or more. The blending amount is not particularly limited and is appropriately selected according to various situations. Usually, it is 0.1 to 40 parts by weight, preferably 0.1 to 100 parts by weight of the polymer material constituting the polyurethane foam. It mix | blends in the ratio of 3-20 mass parts.
Furthermore, as a foam stabilizer, for example, when a silicone surfactant made of a polydimethylsiloxane-polyoxyalkylene copolymer is foamed and cured by the combined use of inert gas and mechanical stirring, the cell diameter is stable. Therefore, it is preferable. The molecular structure of the polydimethylsiloxane-polyoxyalkylene copolymer is usually composed of a polydimethylsiloxane portion having a molecular weight of about 350 to 15,000 and a polyoxyalkylene portion having a molecular weight of about 200 to 9,000. The molecular structure is preferably an addition polymer of ethylene oxide or a co-addition polymer of ethylene oxide and propylene oxide, and its terminal is preferably ethylene oxide. Further, in addition to this silicone surfactant, an ionic surfactant such as cationic, anionic or amphoteric, or a nonionic surfactant such as various polyethers or polyesters may be used in combination.
[0017]
In general, the blending amount of the silicone surfactant is preferably in the range of 0.1 to 10 parts by mass, particularly preferably in the range of 0.5 to 5 parts by mass per 100 parts by mass of the polyol component.
On the other hand, as the urethane reaction catalyst, for example, known catalysts such as monoamines, diamines, triamines, cyclic amines, alcohol amines, ether amines, organometallic compounds are used alone or in combination of two or more. be able to. Among these, when foam-cured by combined use of inert gas and mechanical stirring, cell diameter is stabilized, in particular stannous octoate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin marker peptide, Organometallic compounds such as dibutyltin thiocarboxylate, dibutyltin dimaleate, dioctyltin marker peptide, dioctyltin thiocarboxylate, phenylmercury propionate, octenoate are preferred.
[0018]
As a method for producing polyurethane foam, for example, an inert gas is introduced while mechanically stirring a polyurethane molding material containing a polyol component, a polyisocyanate component and optionally a conductivity imparting agent, a foam stabilizer, a urethane reaction catalyst, and the like. Then, bubbles are mixed, and this is poured into a predetermined mold or the like, or is freely foamed into a block shape, and then heat-cured, or the polyol component is pre-isocyanated, and ethylene glycol or 1,4 -A prepolymer method in which foam curing is performed in the same manner as described above using a chain extender such as butanediol or trimethylolpropane can be used.
Examples of the rotation center axis of the elastic material used in the method of the present invention include plastics such as ABS, POM, polycarbonate, and nylon, metal members obtained by plating steel such as sulfur free-cutting steel with zinc, aluminum, and stainless steel. Although metal members, such as steel and a magnesium alloy, are mentioned, When manufacturing a conductive pseudo spindle type roller, a metal member is preferably used as a rotation center axis.
[0019]
There are no particular restrictions on the method for joining the metal member and the polyurethane foam, but a method in which the metal member is placed in the mold in advance and the polyurethane molding material is cast and cured, or the polyurethane foam is molded into a predetermined shape. Then, a method of adhering can be used. In either method, an adhesive layer can be provided between the metal member and the polyurethane foam as required, and a known material such as an adhesive made of a conductive paint or a hot melt sheet is used as the adhesive layer. Can do.
The roll for an image forming apparatus of the present invention is obtained by grinding the elastic material thus obtained into a pseudo-spindle type as described above using a flat grindstone of a vertical edge.
[0020]
【Example】
EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
Production Example 1 (Production of elastic material for work material)
Propylene oxide and ethylene oxide were randomly added to glycerin to produce a polyether polyol having an oxyethylene unit content of 16% by mass, a functional group number of substantially 3, a weight average molecular weight of 5000, and an OH value of 34 mgKOH / g.
60 parts by mass of this polyether polyol, 40 parts by mass of polytetramethylene ether glycol having a weight average molecular weight of 2000 and an OH value of 56 mgKOH / g, a mixture of diphenylmethane diisocyanate, urethane-modified diphenylmethane diisocyanate and carbodiimide-modified diphenylmethane diisocyanate 3 parts by weight of a mixed isocyanate component of 15% by weight, 4 parts by weight of a silicone foam stabilizer having an OH number of 32 mg KOH / g in a dimethylpolysiloxane-polyoxyalkylene copolymer, 1 part by weight of lauroyliminopropyldimethylethylammonium sulfate Mechanical stirring of 0.005 parts by mass of dibutyltin dilaurate and 3 parts by mass of a black colorant having an OH value of 56 mgKOH / g obtained by dispersing a black pigment in a polyol Mixing while firing, cast the mixture into a metal mold centered on a 6 mm diameter metal shaft, then heat and cure at 100 ° C. for 10 hours, 19 mm diameter and 290 mm long polyurethane foam An elastic material was produced. The foam portion had a bulk density of 0.40 g / ml, an Asker C hardness of 38 °, an average cell diameter of 100 μm, and a maximum cell diameter of 160 μm.
In the same manner as described above, a total of 20 polyurethane foam elastic materials having substantially the same properties were produced.
[0021]
Examples and Comparative Examples About 20 polyurethane foam elastic materials obtained in Production Example 1, a vertical grinding wheel (product name: New Ceramic Grinding Wheel NX80G11VV4A, manufactured by Nitolex Co., Ltd.) with a vertical edge is ground and illustrated. 3, a roller having a difference between the outer diameter B of the central cylindrical portion, the outer diameter A of the cylindrical portion 15 and the outer diameter C of the cylindrical portion 15 ′ was 0.2 mm. The outer diameter B of the central cylindrical portion was 16.0 mm, and the length of the polyurethane foam roller was 320 mm.
About 20 obtained polyurethane foam rollers, the external appearance was observed and the following evaluation criteria evaluated. The results are shown in Table 1.
A: No problem at all.
○: Level at which a spiral striped pattern can be slightly confirmed under a fluorescent lamp Δ: Level at which a spiral striped pattern can be sufficiently confirmed under a fluorescent lamp ×: Level at which a spiral striped pattern can be clearly confirmed
[Table 1]

[0023]
In Table 1, a roller marked with a symbol * has a grinding allowance and a traverse speed within the scope of the present invention, has a good appearance, and has a short grinding time. It can be seen that the traverse speed outside the range of the present invention does not satisfy both the appearance and the grinding time.
Next, a roller manufactured with a grinding allowance of 2.0 mm and a traverse speed of 800 mm / min was incorporated as a transfer roller in the image forming apparatus shown in FIG. A core bar having a diameter of 6 mm protrudes from both ends of the transfer roller, and the protruding portion is pressed against the image forming body by a pressing force of 4.9 N at both ends by a spring. The nip width at both ends of this transfer roller was 2.0 mm, and the nip width at the center was 2.0 mm. Further, when images of gray scale, solid black, and solid white were printed in an environment where the temperature and humidity were 15 ° C. and 10%, good images were obtained.
[0024]
【The invention's effect】
According to the method of the present invention, an image forming apparatus roller having a pseudo-spindle type elastic layer and used as a charging roller, a developing roller, a transfer roller, a toner supply roller, a cleaning roller, etc. It can manufacture efficiently using the edge type perpendicular | vertical type flat grindstone used for manufacture.
[Brief description of the drawings]
FIG. 1 is a schematic diagram illustrating an example of an image forming apparatus using an electrophotographic method.
FIG. 2 is a side explanatory view showing an example of a procedure for manufacturing a pseudo-spindle type roller by grinding an elastic material using a vertical edge grindstone of an edge portion vertical type.
FIG. 3 is a side view of an example of a roller for an image forming apparatus obtained by the method of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Image forming body 2 Developing roller 3 Toner supply roller 4 Layer control blade 5 Transfer roller 6 Cleaning roller 7 Charging roller 8 Transfer material

Claims (8)

A method of manufacturing a roller having a pseudo-spindle type elastic body layer on the outer periphery of a rotation center shaft by grinding an elastic material with a traverse polishing machine using a vertical edge grindstone, and a grinding allowance a (Mm), where b (mm / min) is the traversing speed of the flat grinding wheel, and grinding is performed under the conditions of 2.0 ≦ a ≦ 2.5 and 500 ≦ b ≦ 600. Manufacturing method of apparatus roller.   The pseudo-spindle-type elastic body layer is connected to the central cylindrical portion, the tapered truncated cone portions having the same shape respectively connected to both ends thereof, and to both ends of each circular truncated cone portion, and has a diameter larger than that of the central cylindrical portion. The manufacturing method according to claim 1, which has a structure in which a cylindrical portion having the same shape is integrated.   The manufacturing method according to claim 1 or 2, wherein an outer diameter of a central cylindrical portion of the roller is 0.5 to 5% larger than an outer diameter of both end cylindrical portions.   The ratio of the length of the center cylindrical part of the roller, both truncated cone parts, and both end cylindrical parts is 1: 1.5 to 5.0: 0.8 to 3.0. Production method.   The manufacturing method according to claim 1, wherein the pseudo-spindle elastic body layer is a conductive elastic body layer.   The manufacturing method according to claim 1, wherein the image forming apparatus roller is a charging roller, a developing roller, a transfer roller, a toner supply roller, or a cleaning roller.   The manufacturing method according to claim 6, wherein the image forming apparatus roller is a transfer roller.   An image forming apparatus comprising a roller manufactured by the manufacturing method according to claim 1.

Images