JP2008020558A - Toner supply roller and image forming apparatus using same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner supply roller which has fine and uniform surface cells by an improvement in a foamed polyurethane material and has excellent appearance quality, and an image forming apparatus using the same. <P>SOLUTION: The toner supply roller uses a polyurethane foam obtained by foaming and curing a polyurethane material which includes: (A) a polyether polyol which is prepared by performing addition polymerization of an ethylene oxide or ethylene oxide and propylene oxide to glycerol and has a weight-average molecular weight of 1,000 to 15,000, and has the proportion of a primary hydroxyl group in a terminal hyddroxyl group of 75 to 85 mol%, (B) a polyisocyanate compound, and (C) a silicone-based foam stabilizer composed of a polyorganosiloxane-polyalkylene oxide copolymer which has a polyorganosiloxane segment of a weight-average molecular weight of 400 to 3,000 and polyoxyalkylene segment of a weight-average molecular weight of 1,000 to 7,000 in the proportion of 95:5 to 50:50 in segment ratio. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a toner supply roller (hereinafter, also simply referred to as “roller”) and an image forming apparatus using the same, and more particularly, to an image forming body such as a photoreceptor or paper in an image forming apparatus such as a copying machine or a printer. The present invention relates to a toner supply roller for supplying toner to a developing roller that conveys toner (developer) and forms a visible image on the surface thereof, and an image forming apparatus using the toner supply roller.

  In general, an image forming body that holds an electrostatic latent image and a toner that is in contact with the image forming body and adheres to the surface are attached to a developing unit in an electrophotographic image forming apparatus such as a copying machine or a printer. Thus, a developing roller that visualizes the electrostatic latent image and a toner supply roller that supplies toner to the developing roller are provided, and the toner is transferred from the toner container to the image via the toner supply roller and the developing roller. Image formation is performed by a series of processes for conveying to the formed body.

  In order to perform good image formation in this developing mechanism, it is necessary that a thin layer of toner is uniformly formed and supported on the surface of the developing roller without unevenness. Therefore, in such a developing mechanism, in addition to the toner holding performance of the developing roller itself, the performance of the toner supply roller, particularly the surface performance, becomes important. In other words, the toner supply roller is required to form a uniform toner layer on the surface of the developing roller by contacting the developing roller and performing tribocharging, toner supply, and scraping.

  Various studies have been made in the past to obtain a toner supply roller having satisfactory surface performance that can satisfy the above requirements. In recent years, such a toner supply roller has been devised so that it can contribute to toner transportability and removal of unnecessary toner on the developing roller by laminating an elastic foam having a mesh-like surface structure on the gold shaft. In general, polyurethane foam is suitably used as an elastic foam suitable for this purpose from the viewpoint of flexibility and strength.

As a method for producing such a polyurethane foam roller, a method by die molding is known, and is described in Patent Document 1, for example. Moreover, as a technique related to the improvement of the foamed polyurethane material, for example, in Patent Document 2, a specific polyether polyol in which the proportion of primary hydroxyl groups in the terminal hydroxyl groups is 50 mol% or more, a polyisocyanate compound, and a specific silicone A member for an image forming apparatus using a polyurethane foam obtained by foam-curing a polyurethane molding material containing a system foam stabilizer is disclosed.
Japanese Patent No. 2855335 (Claims etc.) JP 2002-23531 A (Claims etc.)

  As described above, the surface performance is important in the polyurethane foam roller used for the toner supply roller, but depending on the composition of the polyurethane material to be used, the molding conditions such as the mold temperature and surface properties during molding No matter how it is adjusted, a good surface cell may not be obtained in the forming roller. In addition, when improving by changing the mold temperature, there is a difficulty that process control of the set temperature is not easy, and when improving by the surface property of the mold, the surface property (surface roughness) at the time of design is due to wear. There was a problem that it deteriorated and changed, and none of them was a sufficient solution.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a toner supply roller having a fine and uniform surface cell and excellent in appearance quality by solving the above problems and improving the foamed polyurethane material, and an image forming apparatus using the same. is there.

  As a result of intensive studies to solve the above problems, the present inventors have found that when the ratio of primary hydroxyl groups in the polymer chain terminal hydroxyl groups of the polyol constituting the polyurethane material (hereinafter also referred to as “terminal primary OH ratio”) is low, urethane It has been found that the activity during the reaction is reduced and that the resulting roller surface cell has variations in cell diameter. Thus, as a result of further investigation, the present inventors have found that the surface cell can be made uniform by increasing the terminal primary OH ratio in a specific polyurethane material composition, and the present invention has been completed.

  That is, the toner supply roller of the present invention is obtained by addition polymerization of (A) glycerin with ethylene oxide or ethylene oxide and propylene oxide, has a weight average molecular weight of 1000 to 15000, and the ratio of primary hydroxyl groups to terminal hydroxyl groups is 75. A segment ratio of 95 to 85 mol% of polyether polyol, (B) polyisocyanate compound, (C) polyorganosiloxane segment having a weight average molecular weight of 400 to 3000 and polyoxyalkylene segment having a weight average molecular weight of 1000 to 7000 A polyurethane foam formed by foaming and curing a polyurethane material comprising a polyorganosiloxane-polyalkylene oxide copolymer having a ratio of 5 to 50:50, and a silicone-based foam stabilizer. Is

  In the present invention, an aromatic polyisocyanate compound can be suitably used as the (B) polyisocyanate compound, and as the (C) silicone-based foam stabilizer, a polydimethylsiloxane-polyethylene oxide copolymer and / or Polydimethylsiloxane-poly (ethylene oxide / propylene oxide) copolymer is preferred. Moreover, it is preferable that the said polyurethane molding material contains (D) electroconductivity imparting agent further, and a carbon electroconductivity agent is used suitably as this (D) electroconductivity imparting agent.

  An image forming apparatus according to the present invention includes the toner supply roller according to the present invention.

  According to the present invention, the above-described configuration can increase the activity during the urethane reaction, thereby using a toner supply roller having fine and uniform surface cells and excellent in appearance quality, and the same. An image forming apparatus can be realized.

Hereinafter, preferred embodiments of the present invention will be described in detail.
The toner supply roller of the present invention is a polyurethane foam obtained by foaming and curing a polyurethane material containing (A) a specific polyether polyol, (B) a polyisocyanate compound, and (C) a specific silicone-based foam stabilizer. Is used.

  As the polyether polyol of the component (A) used in the present invention, glycerin obtained by addition polymerization of ethylene oxide or ethylene oxide and propylene oxide is used, and the number of moles of addition of ethylene oxide or ethylene oxide and propylene oxide is the obtained polyether. The weight average molecular weight of the polyol is selected in the range of 1000 to 15000. When the weight average molecular weight deviates from the above range, a polyurethane foam having desired physical properties cannot be obtained. A suitable weight average molecular weight is in the range of 2000-8000.

In the present invention, it is important that the proportion of primary hydroxyl groups in the terminal hydroxyl groups of the (A) polyether polyol is 75 to 85 mol%. In other words, by changing the terminal primary OH ratio of the polyol constituting the polyurethane material instead of the molding conditions at the time of molding the mold, the urethane reaction activity is increased, thereby preventing variation in the surface cell of the roller and making it fine. It has become possible to obtain a roller having uniform cells. If the terminal primary OH ratio is less than 75 mol%, a coarse cell is formed and the variation of the surface cell exceeds the allowable range, and if it exceeds 85 mol%, the reaction activity is too high and bubbles are broken. In either case, the intended purpose of the present invention cannot be achieved. In addition, the terminal primary OH ratio of a polyol can be quantified by measuring a proton nuclear magnetic resonance spectrum ( ¹ H-NMR).

  In the present invention, when a polyether polyol obtained by addition polymerization of ethylene oxide and propylene oxide in combination with glycerin is used, the use ratio thereof is not particularly limited. It is necessary to carry out addition polymerization. In this case, the content of the ethylene oxide component in the polyether polyol is usually in the range of 3 to 50% by weight. Moreover, it is preferable that the arrangement | sequence of the oxyethylene group and oxypropylene group in a molecular chain is random.

  In the present invention, as the component (A), one type of the above polyether polyols may be used, or two or more types may be used in combination.

  In the present invention, examples of the polyisocyanate compound used as the component (B) include various aromatic polyisocyanate compounds such as diphenylmethane diisocyanate (MDI) and tolylene diisocyanate (TDI) or their derivatives, hexamethylene diisocyanate ( And various aliphatic polyisocyanate compounds such as HDI) or derivatives thereof, alicyclic polyisocyanate compounds such as isophorone diisocyanate (IPDI), or derivatives thereof. Among these polyisocyanate compounds, since various aromatic polyisocyanate compounds and derivatives thereof are foam-cured by self-generating an inert gas by reaction with the component (A), the cell diameter is stabilized. Particularly preferred.

  As the aromatic polyisocyanate compound, there are polynuclear substances, and pure diphenylmethane diisocyanate obtained from diaminodiphenylmethane, polymeric diphenylmethane diisocyanate obtained from a polynuclear body of diaminodiphenylmethane, and the like can be used. Although there is no restriction | limiting in particular about the functional group number of polymeric diphenylmethane diisocyanate, Usually, the mixture of polymeric diphenylmethane diisocyanate of pure diphenylmethane diisocyanate and various functional groups is used, and an average functional group number becomes like this. Preferably it is 2.05-4. 00, more preferably 2.50 to 3.50. Any of the polyisocyanate compounds can be used as a derivative, such as a urethane-modified product modified with a polyol or the like, a dimer formed by uretidione formation, an isocyanurate-modified product, a carbodiimide / uretonimine-modified product, an allophanate-modified product, a urea-modified product, A burette modified product is used, and a urethane modified product and a carbodiimide / uretonimine modified product are particularly preferable. These polyisocyanate compounds may be used independently and may use 2 or more types together. Also, several types of diphenylmethane diisocyanate and its derivatives can be blended and used. Furthermore, within the range that does not impair the advantages of the present invention, together with diphenylmethane diisocyanate and its derivatives, other aromatic polyisocyanate compounds such as tolylene diisocyanate, various aliphatic polyisocyanate compounds such as hexamethylene diisocyanate, isophorone diisocyanate, etc. You may use together an alicyclic polyisocyanate compound or those derivatives.

  In the present invention, the (A) polyether polyol and (B) polyisocyanate compound have an NCO group / OH group molar ratio of usually 0.9 to 1.5, preferably 1.0 to 1.2. It is advantageous to use at such a ratio.

  Moreover, as a silicone type foam stabilizer of (C) component, the segment ratio 95: 5 to 50:50 is a polyorganosiloxane segment with a weight average molecular weight 400-3000 and a polyoxyalkylene segment with a weight average molecular weight 1000-7000. A polyorganosiloxane-polyalkylene oxide copolymer having a ratio of 90:10 to 60:40 is preferably used. Here, the segment ratio means the ratio of the total number of repeating units constituting each segment. By using a silicone-based foam stabilizer having such properties, when the foam is cured by self-generating an inert gas by the reaction between the component (A) and the component (B), the cell diameter is stable and desired. Of polyurethane foam is obtained.

  The polyorganosiloxane constituting the polyorganosiloxane-polyalkylene oxide copolymer is not particularly limited, and various types can be used, but polydimethylsiloxane is preferred from the viewpoints of effects and economy. is there. On the other hand, the polyalkylene oxide is preferably an ethylene oxide addition polymer or a co-addition polymer of ethylene oxide and propylene oxide. In the case of a co-addition polymer of ethylene oxide and propylene oxide, it is preferably used so that ethylene oxide is 50 to 100 mol% and propylene oxide is 50 to 0 mol%. This silicone type foam stabilizer may be used alone or in combination of two or more.

  In the present invention, an ionic surfactant such as cationic, anionic or amphoteric, or a nonionic surfactant such as various polyethers or polyesters may be used in combination with the silicone-based foam stabilizer. In general, the blending amount of the silicone-based foam stabilizer is preferably in the range of 0.1 to 10 parts by weight, more preferably in the range of 0.5 to 5 parts by weight per 100 parts by weight of the (A) polyether polyol.

  In the present invention, the polyurethane material can be blended with a conductivity imparting agent (D) to impart or adjust the conductivity of the roller. As such a conductivity imparting agent, a carbon conductive agent, an ionic conductive agent, or the like can be used. Among these, examples of the carbon conductive agent include gas black such as electrified black, ketjen black, and acetylene black, oil furnace black including ink black, thermal black, channel black, and lamp black. Examples of the ion conductive agent include tetradecammonium, tetrabutylammonium, dodecyltrimethylammonium such as lauryltrimethylammonium, octadecyltrimethylammonium such as stearyltrimethylammonium, hexadecyltrimethylammonium, benzyltrimethylammonium, and modified aliphatic dimethylethylammonium. Ammonium salts such as perchlorate, chlorate, hydrochloride, bromate, iodate, borofluoride, sulfate, alkyl sulfate, carboxylate, sulfonate, etc .: lithium, sodium Perchlorates, chlorates, hydrochlorides, bromates, iodates, borofluorides, trifluoromethyl sulfates of alkali metals and alkaline earth metals such as calcium and magnesium And sulfonic acid salts, and the like. In the present invention, among the above, a carbon conductive agent can be suitably used, and a conductive carbon dispersion liquid obtained by dispersing carbon black in water together with a surfactant or the like can also be suitably used.

  These conductive agents may be used alone or in combination of two or more. Moreover, there is no restriction | limiting in particular about the compounding quantity, Although it can select suitably as desired, 0.1-40 weight part normally with respect to 100 weight part of polymeric materials which comprise a polyurethane foam, Preferably it is 0.00. It is a ratio of 3 to 20 parts by weight.

  Furthermore, the polyurethane material used in the present invention can be blended with a urethane reaction catalyst and inorganic powders such as magnesium carbonate, calcium carbonate, and magnesium oxide, if desired. Examples of the urethane reaction catalyst include monoamines such as triethylamine and dimethylcyclohexylamine, diamines such as tetramethylethylenediamine, tetramethylpropanediamine, and tetramethylhexanediamine, pentamethyldiethylenetriamine, pentamethyldipropylenetriamine, and tetramethylguanidine. Triamines such as triethylenediamine, dimethylpiperazine, methylethylpiperazine, methylmorpholine, dimethylaminoethylmorpholine, dimethylimidazole and other cyclic amines, dimethylaminoethanol, dimethylaminoethoxyethanol, trimethylaminoethylethanolamine, methylhydroxyethylpiperazine , Alcohol amines such as hydroxyethylmorpholine, bis (dimethyl Ether amines such as (laminoethyl) ether, ethylene glycol bis (dimethyl) aminopropyl ether, stannous octoate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin marker, dibutyltin thiocarboxylate, dibutyltin dimaleate, dioctyltin markertide , Known catalysts such as organometallic compounds such as dioctyltin thiocarboxylate, phenylmercury propionate and octenoate can be used alone or in combination of two or more. Among these, stannous octoate, dibutyltin dichloride are particularly preferred from the viewpoint that the cell diameter is stable when the foam is cured by self-generation of an inert gas by the reaction between the component (A) and the component (B). Organometallic compounds such as acetate, dibutyltin dilaurate, dibutyltin marker, dibutyltin thiocarboxylate, dibutyltin dimaleate, dioctyltin marker, dioctyltin thiocarboxylate, phenylmercury propionate, octenoate are preferred.

  In the present invention, as a method for forming a polyurethane foam, for example, the above-mentioned (A) polyether polyol and (B) polyisocyanate compound are adjusted so that the mixed liquid becomes a predetermined NCO% and prepolymerized (highly polymerized). (C) Silicone foam stabilizer and optionally (D) Conductivity imparting agent and other catalysts Etc. can be mixed and filled in the mold, and then foamed and cured. In the polyurethane foam thus obtained, coarse cells having a cell diameter of 500 μm or more are substantially absent, and the average cell diameter is usually in the range of 350 to 400 μm. The bulk density is preferably about 0.08 to 0.12 g / ml, and the Asker F hardness is preferably in the range of 60 to 90 °.

  The toner supply roller of the present invention uses the above-mentioned polyurethane foam, and is usually provided on the outer periphery of a shaft made of steel such as sulfur free-cutting steel plated with zinc or the like, aluminum, stainless steel, or the like. It is formed by supporting such polyurethane foam so as to cover a part or the whole. If necessary, the surface of the polyurethane foam may be coated with a conductive, semiconductive, or insulating paint.

  The method for joining the shaft and polyurethane foam is not particularly limited. However, the polyurethane material is cast and cured in a state where the shaft is disposed in the mold in advance, or after the polyurethane foam is molded into a predetermined shape. A method of adhering can be used. In any of the methods, an adhesive layer can be provided between the shaft and the polyurethane foam as necessary, 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. In addition, as a method of molding the polyurethane foam, the method of casting into a mold having a predetermined shape described above is used.

  FIG. 1 is a schematic explanatory diagram of an example of the image forming apparatus of the present invention. In the illustrated image forming apparatus, the developing roller 3 is disposed between the toner supply roller 1 and the image forming body 2 holding the electrostatic latent image with the outer peripheral surface thereof being close to the surface of the image forming body 2. The transfer roller 5 is in contact with the image forming body 2 via a recording medium 4 such as paper. When performing image formation in such an image forming apparatus, first, the toner supply roller 1, the image forming body 2, and the developing roller 3 are rotated in the directions of the arrows, respectively, so that the toner is supplied to the developing roller 3 by the toner supplying roller 1. Supplied to the surface. The supplied toner is adjusted to a uniform thin layer on the developing roller 3 by the layer regulating blade 6 and then attached to the latent image on the image forming body 2 so that the latent image is visualized. Next, the toner image on the image forming body 2 can be transferred to the recording medium 4 by generating an electric field between the image forming body 2 and the transfer roller 5. Reference numeral 7 in the drawing denotes a cleaning roller, and the toner remaining on the surface of the image forming body 2 after transfer is removed by the cleaning roller 7. Reference numeral 8 denotes a charging roller.

Hereinafter, the present invention will be described in more detail with reference to examples.
(Examples 1-3 and conventional examples)
The free NCO content in the mixed solution is 5 to 15% with respect to the polyol (polyether polyol, copolymer of ethylene oxide and propylene oxide) having a terminal primary OH ratio and a weight average molecular weight Mw shown in Table 1 below. TDI (T80) was added to obtain a degree of prepolymerization (component 1). Moreover, each material of the component 2 shown in following Table 2 was mixed, and it stirred for 20 minutes at 500 rpm, and produced the phase solution.

  Next, the prepolymer of component 1 and the mixture of component 2 were stirred at an impeller rotational speed of 1000 to 5000 rpm in a low-pressure foaming machine head portion at a low temperature of 20 ° C. or lower in the mixing ratio shown in Table 2 below. Mixed. The obtained mixture was poured into a cylindrical mold, the inlet was closed, and water foaming was performed under pressure (mold temperature was 50 to 70 ° C.), and then the polyurethane foam was placed in an oven at 90 ° C. for 5 minutes. Heated for minutes and allowed to cure. After the mold was cooled, the toner supply roller of each example and the conventional example was obtained by removing the mold. In FIG. 2, the graph of the temperature change of the mixture accompanying a urethane reaction about Example 1 and a prior art example is shown. As shown in the figure, it can be seen that the urethane reaction in Example 1 using a polyol having a high terminal primary OH ratio is more highly exothermic and active than the conventional example using a polyol having a low terminal primary OH ratio.

(Evaluation of surface cell)
The surface of each roller was observed with a video microscope (manufactured by HIROX, Hi-scope KH-2700 (magnification 100 times)), 10 points were taken in the longitudinal direction of the roller, and the cell diameter was measured. The results were evaluated for average cell diameter and standard deviation σ (variation). If the standard deviation σ is 100 μm or less, the variation is good with little variation.

(Evaluation of image quality)
Each roller is incorporated into a commercially available printer, and Xerox 4200 Letter size is used as the paper. The image is a solid image in two environments of normal temperature and normal pressure (25 ° C, 55%) and low temperature and low pressure (10 ° C, 15%). I went out. The evaluation was performed by measuring the average density (three-point measurement average) and density difference of the obtained solid image. For the measurement, a Macbeth color densitometer was used (white 0%, cyan 1.82% setting). A sample having an average density of 0.8 to 1.4% and a density difference of 0.2% or less was rated as “◯”, and a value outside the above conditions was marked as “X”.
These results are shown in the following Table 1 and the graph of FIG.

＊１）各ポリオールの種類：順にＧＬ３０００，Ｅ８２８，ＦＡ７０３，Ｅ２３０（品名，全て三洋化成（株）製）
＊２）重量平均分子量
＊３）官能基数：ポリオールの分岐数
＊４）末端ＯＨ率：分子中のポリエチレンオキサイド含有率（ＥＯ率）
＊５）末端一級ＯＨ率：高分子鎖末端水酸基中の一級水酸基の割合（ＥＯキャップ率）

* 1) Types of each polyol: GL3000, E828, FA703, E230 (Product name, all manufactured by Sanyo Chemical Co., Ltd.)
* 2) Weight average molecular weight * 3) Number of functional groups: Number of branches of polyol * 4) Terminal OH ratio: Polyethylene oxide content (EO ratio) in the molecule
* 5) Terminal primary OH ratio: Ratio of primary hydroxyl group in polymer chain terminal hydroxyl group (EO cap ratio)

＊６）カーボン類：ライオンケミカル（株）製，カーボンペーストＷ３１１Ｎ（導電性カーボン分散液，非イオン系分散剤含有）
＊７）泡触媒：花王（株）製，カオライザーＮｏ．２６（Ｎ，Ｎ−ジメチルアミノエトキシエタノール）
＊８）樹脂化触媒：花王（株）製，カオライザーＮｏ．３１（３３％トリエチレンジアミン，６７％ジプロピレングリコール）
＊９）シリコーン系整泡剤：日本ユニカー（株）製，ＳＺ１１２７（ポリジメチルシロキサン−ポリ（エチレンオキシド・プロピレンオキシド）共重合物）

* 6) Carbon: manufactured by Lion Chemical Co., Ltd., carbon paste W311N (conducting carbon dispersion, containing nonionic dispersant)
* 7) Foam catalyst: Kao No. manufactured by Kao Corporation. 26 (N, N-dimethylaminoethoxyethanol)
* 8) Resin catalyst: Kao No. manufactured by Kao Corporation. 31 (33% triethylenediamine, 67% dipropylene glycol)
* 9) Silicone type foam stabilizer: Nippon Unicar Co., Ltd., SZ1127 (polydimethylsiloxane-poly (ethylene oxide / propylene oxide) copolymer)

  As can be seen from the results of Table 1 and FIG. 3, the terminal primary OH ratio, the average cell diameter, and the variation in the cell diameter show an inversely proportional relationship. In particular, in Example 1 having the highest terminal primary OH ratio, the average cell It can be seen that the diameter is extremely small and variation is suppressed. That is, in the roller of the example using the polyol having a high terminal primary OH ratio, the average cell diameter is smaller than that of the conventional example, and the variation in the cell diameter is suppressed to be low, and as a result, good image quality is obtained. It was confirmed that it was obtained.

1 is a schematic explanatory diagram illustrating an example of an image forming apparatus of the present invention. It is a graph which shows the temperature change of the mixture accompanying a urethane reaction about Example 1 and a prior art example. It is a graph which shows the evaluation result of the average cell diameter and standard deviation (sigma) in an Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Toner supply roller 2 Image forming body 3 Developing roller 4 Recording medium 5 Transfer roller 6 Layer regulation blade 7 Cleaning roller 8 Charging roller

Claims (6)

  (A) a polyether polyol obtained by addition-polymerizing ethylene oxide or ethylene oxide and propylene oxide to glycerin, having a weight average molecular weight of 1000 to 15000 and a proportion of primary hydroxyl groups in terminal hydroxyl groups of 75 to 85 mol%; , (B) a polyisocyanate compound, (C) a polyorganosiloxane segment having a weight average molecular weight of 400 to 3000 and a polyoxyalkylene segment having a weight average molecular weight of 1000 to 7000 at a segment ratio of 95: 5 to 50:50. A toner supply roller comprising a polyurethane foam formed by foaming and curing a polyurethane material containing a silicone-based foam stabilizer made of a polyorganosiloxane-polyalkylene oxide copolymer.   The toner supply roller according to claim 1, wherein the (B) polyisocyanate compound is an aromatic polyisocyanate compound.   The toner supply roller according to claim 1, wherein the (C) silicone-based foam stabilizer is a polydimethylsiloxane-polyethylene oxide copolymer and / or a polydimethylsiloxane-poly (ethylene oxide / propylene oxide) copolymer.   The toner supply roller according to claim 1, wherein the polyurethane molding material further contains (D) a conductivity imparting agent.   The toner supply roller according to claim 4, wherein the conductivity imparting agent (D) is a carbon conductive agent.   An image forming apparatus comprising the toner supply roller according to claim 1.

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