JP6869792B2 - Electrophotographic conductive members, electrophotographic process cartridges and electrophotographic image forming devices - Google Patents

Description

The present invention relates to a conductive member for electrophotographic, an electrophotographic process cartridge, and an electrophotographic image forming apparatus.

Various conductive members are used in the electrophotographic image forming apparatus. Examples of the conductive member include a developing member that appropriately charges the developing agent, a charging member that charges the photoconductor, and the like. These electrophotographic conductive members are required to have precise physical properties of electrical resistance in order to control static electricity for the purpose of obtaining a good image as well as appropriate flexibility.

As the conductive member, a conductive elastic member in which electron conductive particles such as carbon black, metal oxide, and metal powder are mixed and dispersed in a polymer binder may be used. These electronically conductive particles have the advantage of having high conductivity and small environmental fluctuation. Further, a conductive member obtained by adding an ionic conductive agent to a polymer binder to adjust the resistance can also be mentioned. For these, conductive members with less uneven resistance can be obtained.

Then, a conductive member of a conductive agent combination system in which both electron conductive particles and an ionic conductive agent are added to a polymer binder has also been proposed. The effect of suppressing both the local resistance variation of electron conductivity and the environmental fluctuation of ionic conductivity has been presented (Patent Document 1). In addition, in order to suppress an increase in the resistance of the ionic conductive member, one of the ions ionized from the ionic conductive agent is chemically reacted with a polymer binder and fixed, which is an ion-fixed type hybrid conductive conductivity. Members have also been proposed (Patent Document 2).

Japanese Unexamined Patent Publication No. 2005-220317 Japanese Unexamined Patent Publication No. 2016-12219

However, as a result of diligent studies by the present inventors, the following problems may occur when a conductive member of a conductive agent combination system to which both electronic conductive particles and an ionic conductive agent are added is used. I found.

That is, when the conductive member is energized for a long time and repeatedly vibrated, electronically conductive particles such as carbon black may move in the polymer binder and aggregate. When the electron conductive particles are aggregated, the conductive path for exhibiting the electron conductivity is blocked, the electron conductivity, which is one of the acting mechanisms responsible for the conductivity, is reduced, and the electric resistance is increased.

As for the ionic conductive agent, the ion species that are not fixed by energization may move and be polarized, and the ions responsible for the transfer of electric charge may be absent and the electric resistance may increase. That is, when energized, both the electron conductivity and the ionic conductivity are reduced, and the conductivity is lowered.

As a result of the above phenomenon, the electrical resistance of the conductive member increases, and it may be difficult to provide a conductive member for electrophotographic photography having a long life.

One aspect of the present invention is to provide a conductive member for electrophotographic photography in which a change in electrical resistance is small even when subjected to long-term energization and mechanical repeated stress.

Another aspect of the present invention is to provide an electrophotographic image forming apparatus and a process cartridge that contribute to the formation of a high-quality electrophotographic image.

According to one aspect of the present invention, the electrophotographic conductive member has a conductive substrate, an elastic layer on the conductive substrate, and a conductive surface layer on the elastic layer.
The conductive surface layer is
i) Urethane resin and
ii) Carbon black and
iii) Ion conductive agent and
Contains,
The urethane resin is not covalently bonded to the ionic conductive agent and is not covalently bonded.
The carbon black is provided with an electrophotographic conductive member bonded to the urethane resin via a structure represented by the following formula (1):

（式（１）において、Ｒ_１は炭素数１〜６のアルキレン基を示す。Ｒ_２は水素原子、炭素数１〜４のアルキル基、炭素数１〜４のアミノアルキル基又はフェニル基を示す。^＊１−１、*１−２および*１−３は、各々独立に、該カーボンブラックとの結合部位、水素原子との結合部位およびケイ素原子との結合部位のいずれかを示し、^＊１−１、*１−２および*１−３のうちの少なくとも１つは、該カーボンブラックとの結合部位である。^＊２は該ウレタン樹脂との結合部位を示す。）。

(In the formula (1), R ₁ represents an alkylene group having 1 to 6 _{carbon atoms. R 2} represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an aminoalkyl group having 1 to 4 carbon atoms or a phenyl group. ^* 1-1, * 1-2, and * 1-3 independently indicate any of the bonding sites with the carbon black, the bonding site with the hydrogen atom, and the bonding site with the silicon atom, ^* 1 At least one of -1, * 1-2 and * 1-3 is a bonding site with the carbon black. ^* 2 indicates a bonding site with the urethane resin).

Further, according to another aspect of the present invention, the electrophotographic conductive member has a conductive substrate, an elastic layer on the conductive substrate, and a conductive surface layer on the elastic layer.
The conductive surface layer is
iv) Acid carbon black and
v) The compound represented by the following formula (2) and
vi) Polyol and
vii) Isocyanate compound and
viii) An ionic conductive agent that does not covalently bond with the polyol and the isocyanate compound,
An electrophotographic conductive member containing a crosslinked mixture containing:

（式（２）において、Ｒ_３は炭素数１〜６のアルキレン基を示す。Ｒ_４は水素原子、炭素数１〜４のアルキル基、炭素数１〜４のアミノアルキル基又はフェニル基を示す。Ｒ_５は水素原子又は炭素数１〜４のアルキル基を示す。）。

(In the formula (2), R ₃ represents an alkylene group having 1 to 6 _{carbon atoms. R 4} represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an aminoalkyl group having 1 to 4 carbon atoms or a phenyl group. . R ₅ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.)

According to another aspect of the present invention, an electrophotographic process cartridge having the above-mentioned conductive member for electrophotographic is provided.

Further, according to still another aspect of the present invention, there is provided an electrophotographic image forming apparatus having the above-mentioned conductive member for electrophotographic.

According to one aspect of the present invention, it is possible to obtain an electrophotographic conductive member having a small change in electrical resistance even when subjected to long-term energization and mechanical repeated stress.

In another aspect of the present invention, an electrophotographic image forming apparatus and an electrophotographic process cartridge that contribute to the formation of a high-quality electrophotographic image can be obtained.

It is sectional drawing which shows an example of the conductive member for electrophotographic which concerns on this invention. It is sectional drawing which shows an example of the electrophotographic process cartridge which concerns on this invention. It is sectional drawing which shows an example of the electrophotographic image forming apparatus which concerns on this invention. It is a figure which shows the method of measuring the electric resistance of the conductive member for electrophotographic which concerns on this invention.

Hereinafter, embodiments of the present invention will be described in detail.

[Conductive member for electrophotographic]
The first embodiment of the electrophotographic conductive member according to the present invention has a conductive substrate, an elastic layer on the conductive substrate, and a conductive surface layer on the elastic layer. Here, the conductive surface layer contains i) urethane resin, ii) carbon black, and iii) ionic conductive agent. Further, the urethane resin is not covalently bonded to the ionic conductive agent. Further, the carbon black is bonded to the urethane resin via a structure represented by the following formula (1).

式（１）において、Ｒ_１は炭素数１〜６のアルキレン基を示す。Ｒ_２は水素原子、炭素数１〜４のアルキル基、炭素数１〜４のアミノアルキル基又はフェニル基を示す。^＊１−１、*１−２および*１−３は、各々独立に、該カーボンブラックとの結合部位、水素原子との結合部位およびケイ素原子との結合部位のいずれかを示す。また、^＊１−１、*１−２および*１−３のうちの少なくとも１つは、該カーボンブラックとの結合部位である。すなわち、式（１）における３つのＳｉ−Ｏ−のうち少なくとも１つはカーボンブラックと結合しており、他のＳｉ−Ｏ−はシラノール基またはシロキサン結合を形成している。^＊２は該ウレタン樹脂との結合部位を示す。

In the formula (1), R ₁ represents an alkylene group having 1 to 6 carbon atoms. R ₂ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an aminoalkyl group having 1 to 4 carbon atoms, or a phenyl group. ^* 1-1, * 1-2 and * 1-3 each independently indicate one of the binding site with the carbon black, the binding site with the hydrogen atom, and the binding site with the silicon atom. Further, ^{at least one of *} 1-1, * 1-2 and * 1-3 is a binding site with the carbon black. That is, at least one of the three Si—O−s in the formula (1) is bonded to carbon black, and the other Si—O−s form a silanol group or a siloxane bond. ^* 2 indicates the binding site with the urethane resin.

A second embodiment of the electrophotographic conductive member according to the present invention has a conductive substrate, an elastic layer on the conductive substrate, and a conductive surface layer on the elastic layer. Here, the conductive surface layer contains a crosslinked product of a mixture containing iv) to vivi) below. iv) Acidic carbon black, v) Compound represented by the following formula (2), vi) Polyol, vii) Isocyanate compound, and viii) The polyol and an ionic conductive agent that does not covalently bond with the isocyanate compound.

式（２）において、Ｒ_３は炭素数１〜６のアルキレン基を示す。Ｒ_４は水素原子、炭素数１〜４のアルキル基、炭素数１〜４のアミノアルキル基又はフェニル基を示す。Ｒ_５は水素原子又は炭素数１〜４のアルキル基を示す。該架橋物は、該ポリオールと該イソシアネート化合物とのウレタン化物であるウレタン樹脂と、該酸性カーボンブラックと、該イオン導電剤とを含む。該架橋物において、前記式（２）で示される化合物は該酸性カーボンブラック及び該ウレタン樹脂と反応することで、該酸性カーボンブラックは前記式（１）で示される構造を介して該ウレタン樹脂と結合している。また、該イオン導電剤は該ポリオール及び該イソシアネート化合物とは共有結合しないため、該架橋物において、該ウレタン樹脂は該イオン導電剤と共有結合していない。

In formula (2), R ₃ represents an alkylene group having 1 to 6 carbon atoms. R ₄ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an aminoalkyl group or a phenyl group having 1 to 4 carbon atoms. R ₅ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. The crosslinked product contains a urethane resin which is a urethane compound of the polyol and the isocyanate compound, the acidic carbon black, and the ionic conductive agent. In the crosslinked product, the compound represented by the formula (2) reacts with the acidic carbon black and the urethane resin, so that the acidic carbon black reacts with the urethane resin via the structure represented by the formula (1). It is combined. Further, since the ionic conductive agent does not covalently bond with the polyol and the isocyanate compound, the urethane resin is not covalently bonded with the ionic conductive agent in the crosslinked product.

The electrophotographic conductive member (hereinafter, also referred to as a conductive member) according to the first and second embodiments has good conductivity by using ion conductivity by an ion conductive agent and electron conductivity by carbon black in combination. The rate can be shown and minute resistance unevenness can be suppressed. In addition, since the carbon black is covalently fixed to the urethane resin that is the binder, the carbon black does not move in the urethane resin even if it is subjected to long-term energization or repeated vibration. Since the carbon black does not move, the carbon black does not aggregate due to energization or repeated vibration, and the electron conductive path does not change. Therefore, even if the electrophotographic image forming apparatus incorporating the conductive member according to the present invention is used for a long time, the change in electron conductivity carried by carbon black in the conductive member is very small.

Further, the carbon black and the urethane resin are bonded to each other via the structure represented by the formula (1), and the unpaired electrons in the structure are gently attracted to the ionic conductive agent. As a result, the electric charge flowing through the electronically conductive carbon black is smoothly transferred to the ionic conductive agent existing in the vicinity of the carbon black at a short distance. Therefore, it is considered that the resistance between the electron conductive portion and the ionic conductive portion becomes small and the conductivity becomes stable.

In addition, since the structure represented by the formula (1) is bonded to the urethane resin, the movement of ions of the ionic conductive agent is appropriately suppressed, and the polarization of the ionic conductive agent is less likely to occur. That is, it is suppressed that the positive and negative ions of the ion conductive agent are completely separated and discharged to the outside of the conductive surface layer, and the ion conductivity of the conductive member due to the depletion of ions in the conductive surface layer due to energization. It is possible to suppress the deterioration of sex. In addition, the ion conductive agent is mainly responsible for conducting a short distance with carbon black, and since the ions do not move a long distance, the polarization of the ion conductive agent is further suppressed. Therefore, it is considered that the polarization of the ionic conductive agent is unlikely to occur even if the electrophotographic image forming apparatus is used for a long time, and the ionic conductivity does not change, so that the change in electrical resistance becomes small.

As described above, while the electronic conductivity due to carbon black and the ionic conductivity due to the ionic conductive agent complement each other, the change when both are energized or repeatedly stressed is small. Therefore, the conductive member according to the present invention. Then the change in electrical resistance is small.

An example of the conductive member according to the present invention is shown in FIG. FIG. 1A is a schematic cross-sectional view of the conductive member in a direction orthogonal to the axial direction of the conductive substrate 1. FIG. 1B is a schematic cross-sectional view in the axial direction. In FIGS. 1A and 1B, the conductive member is a conductive substrate 1, an elastic layer 2 that covers the periphery of the conductive substrate 1, and a conductive surface layer 3 that covers the periphery of the elastic layer 2. Has.

<Silane compound>
In the second embodiment of the conductive member according to the present invention, the silane compound represented by the above formula (2) is used. The hydrolyzable group (-OR ₅ ) of the silane compound can mainly react with the carboxyl group on the surface of acidic carbon black after hydrolysis to form a covalent bond. Further, the amino group (-NHR ₄ ) of the silane compound can react with the terminal isocyanate group of the urethane resin, which is a urethane compound of the polyol and the isocyanate compound, to form a covalent bond (urea bond). By reacting with the acidic carbon black and the urethane resin, the silane compound can bond the acidic carbon black and the urethane resin via the structure represented by the formula (1). _{That is, R 3} in the formula (2) _{corresponds to R 1} in the formula (1) _{, and R 4} in the formula (2) corresponds to _{R 2} in the formula (1).

In the formula (2), R ₃ is an alkylene group having 1 to 6 carbon atoms, and preferably an alkylene group having 1 to 3 carbon atoms. Examples of R ₃ include a methylene group, an ethylene group, and a trimethylene group. The same applies to _{R 1} in the above formula (1). When the number of carbon atoms is 6 or less, the carbon black does not form a resistance layer when it reacts with the surface of the carbon black, and good conductivity can be obtained between the carbon black and the urethane resin. On the other hand, when the long-chain alkylene group having 7 or more carbon atoms completely covers the surface of carbon black, it coats the surface of carbon black like an insulating and less polar film. Then, the electrons cannot pass through the insulating film, and the electron conductive mechanism does not work. Further, in the urethane resin, an ionic conductive agent including the periphery of the structure represented by the above formula (1), and hydroxide ions and oxonium ions caused by water polarized by the ionic conductive agent are present. When a long-chain alkylene group completely covers the surface of carbon black to form a low-polarity film, the ion conductive agent and ions caused by water polarized by the ion conductive agent cannot approach the carbon black, and charge exchange occurs. Can not be done. As a result, it becomes difficult to transfer the electric charge between the electron conductive mechanism of carbon black and the ion conductive mechanism by the ion conductive agent, and the electric resistance becomes large.

In the formula (2), R ₄ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an aminoalkyl group having 1 to 4 carbon atoms, or a phenyl group. Examples of the alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, a propyl group and a butyl group. Examples of the aminoalkyl group having 1 to 4 carbon atoms include an aminomethyl group, an aminoethyl group, an aminopropyl group and an aminobutyl group. By carbon number of the alkyl group and the amino group of 4 or less is preferable because a good conductive layer by the same reason as R _3. The carbon number is preferably 1 to 3, more preferably 1 to 2. The same applies to _{R 2} in the above formula (1).

In the formula (2), R ₅ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Examples of the alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, a propyl group and a butyl group. When the number of carbon atoms of the alkyl group is 4 or less, the reactivity of the carbon black to the surface is increased, and it is easy to uniformly bond to the surface of the carbon black, which is preferable. The carbon number is preferably 1 to 3, more preferably 1 to 2.

Examples of commercially available silane compounds represented by the formula (2) include KBM-603, KBE-903, KBM-573, KBM-903 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.), T2868 (commodity). Name, manufactured by Tokyo Kasei Kogyo Co., Ltd., etc. Among these, KBM-903 is preferable. These may be used alone or in combination of two or more.

In the second embodiment of the conductive member according to the present invention, the blending amount of the silane compound represented by the formula (2) is preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of acidic carbon black. .. The blending amount is more preferably 0.2 to 5 parts by mass, still more preferably 0.3 to 2 parts by mass with respect to 100 parts by mass of acidic carbon black. When the blending amount is within the range, the amount of the silane compound is sufficient to make it difficult for the silane compound to react with the acidic carbon black and the urethane resin to cause a change in electrical resistance when energized or repeatedly stressed. It is possible to form the structure represented by the formula (1).

<Carbon black>
In the conductive member according to the present invention, carbon black is dispersed in the conductive surface layer, and a part of the conductivity is borne by the electronic conductivity of the carbon black. The carbon black is required to be capable of binding to the silane compound represented by the above formula (2), and is preferably an acidic carbon black. The acidic carbon black has a sufficient number of functional groups, particularly carboxyl groups, necessary for covalent bonding with the silane compound. On the other hand, in the case of neutral to alkaline carbon black, a sufficient amount of carboxyl groups are not present on the surface of the carbon black, and it is difficult to sufficiently covalently bond with the silane compound. The acidic carbon black is a carbon black having a pH value of 5 or less. The pH value is preferably 4.5 or less, more preferably 4 or less. The pH value is a value measured according to JIS K 5101-172: 2004.

Preferred carbon blacks include, for example, the following carbon blacks in commercially available products. Special Black S160 (trade name, manufactured by Orion Engineered Carbons Co., Ltd.), SUNBLACK X15 (trade name, manufactured by Asahi Carbon Co., Ltd.), MA77 (trade name, manufactured by Mitsubishi Chemical Corporation). Among these, MA77 is more preferable. These may be used alone or in combination of two or more.

The blending amount of carbon black is preferably 0.5 to 20 parts by mass, and more preferably 1 to 10 parts by mass with respect to 100 parts by mass of the urethane resin (urethane compound of a polyol and an isocyanate compound). When the blending amount is within the range, the carbon black can sufficiently bear the electronic conductivity and the conductive member can have an appropriate electric resistance while maintaining the flexibility of the conductive surface layer. The electronic conductivity of carbon black can be adjusted so that the conductive surface layer has medium resistance by using it in combination with the ionic conductivity of the ionic conductive agent. Further, the electron conductivity can be adjusted by changing the values such as the amount of carbon black added, the dispersibility, the primary particle size, and the amount of DBP oil absorbed.

<Ion conductive agent>
The ionic conductive agent dissociates into ions in a urethane resin, which is a binder, and exhibits ionic conductivity. The ionic conductive agent does not covalently bond with the urethane resin. Further, it does not covalently bond with the polyol and the isocyanate compound which are the raw materials of the urethane resin.

Examples of the cation of such an ionic conductive agent include lithium ion, sodium ion, potassium ion, tetraethylammonium ion, tetrabutylammonium ion, octyltrimethylammonium ion, lauryltrimethylammonium ion, stearyltrimethylammonium ion, and octadecyltrimethylammonium ion. , Dodecyltrimethylammonium ion, hexadecyltrimethylammonium ion, trioctylpropylammonium ion and the like.

Examples of anions constituting the ionic conductive agent include chloride ion, bromide ion, nitrate ion, sulfate ion, chlorate ion, perchlorate ion, bis (trifluoromethanesulfonyl) imide (TFSI) anion, and bis (fluorosulfonyl). ) Imid (FSI) anion, bis (nonafluorobutanesulfonyl) imide anion, boron-based ion such as tetraphenylborate, phosphorus-based ion such as hexafluorophosphite and the like can be mentioned. Among these, as the anion, a bis (trifluoromethanesulfonyl) imide (TFSI) anion and a bis (fluorosulfonyl) imide (FSI) anion are preferable from the viewpoint of being advantageous in reducing the electrical resistance of the conductive surface layer.

Specific examples of the ionic conductive agent include compounds represented by the following formulas (3), compounds represented by the following formulas (10) to (15), and the like. Among these, the compound represented by the following formula (3) is preferable from the viewpoint of being advantageous in reducing the electrical resistance of the conductive surface layer. These may be used alone or in combination of two or more.

イオン導電剤の配合量としては、カーボンブラック１００質量部に対して好ましくは１から２０質量部、より好ましくは２から１５質量部、さらに好ましくは３から１０質量部である。該配合量が該範囲内であることにより、イオン導電剤が担うイオン導電性とカーボンブラックが担う電子導電性の双方が共同して導電性を担い、導電性部材の抵抗上昇を抑制することができる。

The blending amount of the ionic conductive agent is preferably 1 to 20 parts by mass, more preferably 2 to 15 parts by mass, and further preferably 3 to 10 parts by mass with respect to 100 parts by mass of carbon black. When the blending amount is within the range, both the ionic conductivity carried by the ionic conductive agent and the electronic conductivity carried by carbon black jointly bear the conductivity, and the increase in the resistance of the conductive member can be suppressed. it can.

<Urethane resin>
In the present invention, urethane resin is used as a binder for the conductive surface layer. Urethane resin has high performance in both flexibility and breaking strength, and is suitably used as a conductive surface layer of a conductive member for electrophotographic. Urethane resin is produced by reacting a polyol and an isocyanate compound by a urethanization reaction. Regarding the cross-linking points due to the urethanization reaction, when the cross-linking point density is high, a hard and tough conductive surface layer is obtained, and when the cross-linking point density is low, a flexible and highly ionic conductive surface layer is obtained. The equivalent ratio (NCO / OH ratio) of the polyol to the isocyanate compound is appropriately selected according to the desired hardness and conductivity of the conductive surface layer. The NCO / OH ratio is preferably 1.0 or more. When the NCO / OH ratio is 1.0 or more, polyols that do not covalently bond are unlikely to be generated, and problems of moving and bleeding due to long-term standing are unlikely to occur. Further, the carbon black is easily bonded to the urethane resin, and the carbon black is less likely to move in the conductive surface layer due to repeated vibration and energization for a long period of time, and the electric resistance is less likely to change.

<Polyol>
Examples of the polyol include polyether polyols, polyester polyols, polycarbonate polyols, polyurethane polyols, acrylic polyols and the like. These may be used alone or in combination of two or more. Among these, polyether polyols and polyester polyols are preferably used from the viewpoint of conductivity and flexibility. Examples of the polyether polyol include polyethylene glycol, polypropylene glycol, polytetramethylene glycol and the like. Further, as the polyester polyol, a diol component such as 1,4-butanediol, 3-methyl-1,4-pentanediol and neopentyl glycol, a triol component such as trimethylolpropane, and an adipic acid and phthalic anhydride, Examples thereof include polyester polyol obtained by a condensation reaction with a dicarboxylic acid such as terephthalic acid and hexahydroxyphthalic acid. The polyether polyol and the polyester polyol may be chain-extended with an isocyanate such as 2,4-tolylene diisocyanate (TDI), 1,4-diphenylmethane diisocyanate (MDI), and isophorone diisocyanate (IPDI).

<Isocyanate compound>
The isocyanate compound is not particularly limited, but is limited to ethylene diisocyanate, aliphatic polyisocyanate such as 1,6-hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), cyclohexane 1,3-diisocyanate, cyclohexane 1, Alicyclic polyisocyanate such as 4-diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), polypeptide diphenylmethane diisocyanate, xylylene diisocyanate, naphthalene Aromatic isocyanates such as diisocyanates, copolymers thereof, isocyanurates, TMP adducts, biurets, blocks thereof, and the like can be used. Further, these isocyanate compounds may be reacted with the polyol to form a chain-extended prepolymer before use. These may be used alone or in combination of two or more. Among these, aromatic isocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, and polyether diphenylmethane diisocyanate are preferable. These isocyanate compounds are preferably used as blocked isocyanates blocked with methylethylketone oxime in order to prevent them from reacting with water before reacting with polyols.

<Conductive substrate>
The conductive substrate functions as an electrode and a support member of the conductive member. The conductive substrate shall be composed of a metal or alloy such as aluminum, copper alloy, stainless steel; iron plated with chromium or nickel; a rigid and conductive material such as synthetic resin imparted with conductivity. Can be done. A primer may be applied to the surface of the conductive substrate in order to improve the adhesiveness between the conductive substrate and the elastic layer. Examples of primers include silane coupling agent-based primers, urethane-based, acrylic-based, polyester-based, polyether-based or epoxy-based thermosetting resins, thermoplastic resins and the like.

<Elastic layer>
In the conductive member according to the present invention, an elastic layer having elasticity is provided on the conductive substrate in order to bring it into uniform contact with other members. As the material for the elastic layer, various rubber materials can be used. Examples of the rubber used for the rubber material include the following. Ethylene-propylene-diene copolymer rubber (EPDM), acrylonitrile-butadiene rubber (NBR), chloroprene rubber (CR), natural rubber (NR), isoprene rubber (IR), styrene-butadiene rubber (SBR), fluororubber, silicone Rubber, epichlorohydrin rubber, urethane rubber. These can be used alone or in combination of two or more. Among these, silicone rubber is preferable. Examples of the silicone rubber include polydimethylsiloxane, polymethyltrifluoropropylsiloxane, polymethylvinylsiloxane, polyphenylvinylsiloxane, and copolymers of these siloxanes.

Various additives such as a conductivity-imparting agent, a non-conductive filler, and a catalyst are appropriately blended in the elastic layer. As the conductivity-imparting agent, particles of a conductive metal such as aluminum and copper, particles of a conductive metal oxide such as zinc oxide, tin oxide and titanium oxide, carbon black and the like can be used. Of these, carbon black is preferable because it is relatively easily available and good conductivity can be obtained. When carbon black is used as the conductivity-imparting agent, it is preferable to add 3 to 80 parts by mass of carbon black to 100 parts by mass of rubber in the rubber material. Examples of the non-conductive filler include silica, quartz powder, titanium oxide, zinc oxide, calcium carbonate and the like. The thickness of the elastic layer is preferably in the range of 0.5 to 5.0 mm, more preferably in the range of 2.0 to 4.0 mm. The elastic layer may be provided on the conductive substrate, and it is not necessary to cover the entire surface of the conductive substrate.

<Conductive surface layer>
In the conductive member according to the present invention, a conductive surface layer is provided on the elastic layer. The conductive surface layer contains the urethane resin, the carbon black, and the ionic conductive agent. The urethane resin and the carbon black are bonded by the structure represented by the formula (1), but the urethane resin is not covalently bonded to the ionic conductive agent. The conductive surface layer may be provided on the elastic layer, and it is not necessary to cover the entire surface of the elastic layer.

The conductive surface layer can be provided, for example, by mixing and dispersing a material and a solvent, preparing a coating material for a conductive surface layer, and applying the coating material. There are two methods for preparing the coating material for the conductive surface layer. The first method is a method of mixing and dispersing a polyol and an isocyanate compound which are raw materials of a urethane resin, a compound represented by the above formula (2), carbon black, an ionic conductive agent, other materials and a solvent. In the second method, the compound represented by the above formula (2) is reacted with carbon black in advance to prepare a coated carbon black coated with a silane compound, and the coated carbon black and another material are used. It is a method of mixing and dispersing.

In order to more sufficiently covalently bond the carbon black and the compound represented by the formula (2), it is preferable to react the carbon black with the compound represented by the formula (2) in advance. The following two methods can be mentioned as a method of reacting carbon black with the compound represented by the formula (2) in advance. In the first method, a compound represented by the above formula (2) dissolved in a solvent is sprayed onto a stirring place where carbon black powder is agitated, mixed, and dried to prepare a coated carbon black. How to do it. The second method is a method in which carbon black, a solvent, and a compound represented by the above formula (2) are mixed, dispersed and made into a slurry, and the slurry is dried to obtain a coated carbon black. Examples of the dispersion method include a method using the following devices. Rotating blades rotated by a motor, stirring and dispersing device such as homogenizer; fine orifice dispersion device that disperses pigment by colliding accelerated paint; dispersing device using beads such as sand mill, paint shaker, dyno mill and pearl mill.

The conductive surface layer coating material may optionally include other materials such as those listed below. Rough particles that adjust surface roughness, leveling agents that facilitate coating, reinforcing particles that increase the strength of the conductive surface layer, and low-polarity compounds that reduce surface friction and dirt. The coating material for the conductive surface layer may contain one of these, or may contain two or more of them.

The conductive surface layer is formed by applying the conductive surface layer coating material to the surface of the elastic layer and drying the coating. Examples of the coating method include spray coating, roll coater coating, push-up coating, ring coating, immersion coating and the like. Immersion coating is preferable from the viewpoint of uniformity in the thickness of the obtained conductive surface layer. The thickness of the conductive surface layer is preferably 1 to 500 μm, more preferably 2 to 100 μm, and even more preferably 5 to 30 μm. In order to adjust the thickness of the conductive surface layer within the range, for example, the solid content of the resin of the coating material for the conductive surface layer and the coating pulling speed can be controlled. Increasing the solid content of the resin in the paint for the conductive surface layer makes the conductive surface layer thicker, and decreasing it makes it thinner. For example, the solid content of the resin with respect to 100 parts by mass of the volatile solvent in the coating material for the conductive surface layer can be adjusted to 10 parts by mass or more and 40 parts by mass or less. Further, increasing the coating pulling speed increases the thickness, and decreasing it decreases the thickness. For example, it is preferable to adjust the coating pulling speed to 1 mm / min or more and 300 mm / min or less.

^{The volume resistivity of the conductive surface layer is in a medium resistance region (1 × 10 3} to 1 × 10 ⁹ Ω · cm) in a room temperature and humidity (N / N) environment (temperature 23 ° C., relative humidity 55%). Is preferable. The volume resistivity can be adjusted by increasing or decreasing the amount of carbon black to be blended, the amount of ionic conductive agent, the amount of other materials added, and the dispersion strength so as to obtain a desired value.

In the present invention, the volume resistivity of the coating film for the conductive surface layer and the electrical resistance of the conductive member are measured by the following methods.

(Volume resistivity of paint film for conductive surface layer)
A conductive surface layer paint is applied on an aluminum sheet with a thickness of 100 μm using an applicator, air-dried in an environment at room temperature for 5 minutes, dried in an oven at 150 ° C. for 1 hour and 30 minutes, fired, and thickened. A coating film having a size of 25 μm is prepared. Platinum is vapor-deposited on one side to prepare an electrode and a guard electrode. After leaving it in an N / N environment for 12 hours or more, a voltage of 100 V is applied between both electrodes using a micro ammeter (trade name: ADVANTEST R8340A ULTRA HIGH RESISTANCE METER, manufactured by Advantest Co., Ltd.), and the current after 30 seconds. To measure. The volume resistivity is calculated from the measured value of the current, the thickness, and the electrode area.

(Electrical resistance of conductive members)
In the measurement of the electrical resistance of the conductive member, as shown in FIG. 4, the conductive member 19 is made of a cylindrical metal having the same curvature as the photoconductor under the stress corresponding to the usage state when used in the electrophotographic image forming apparatus. Measure the resistance when the wire is brought into contact with 20 and energized. Specifically, in FIG. 4A, the bearings 23a and 23b fixed to the weight apply a stress pushing vertically downward to both ends of the conductive substrate 1 of the conductive member 19. The cylindrical metal 20 is located in parallel with the conductive member 19 in the vertical direction of the conductive member 19. Then, the conductive member 19 is pressed against the bearings 23a and 23b as shown in FIG. 4B while rotating the cylindrical metal 20 by a driving device (not shown). The cylindrical metal 20 is rotated at the same rotation speed as the photoconductor drum in the used state, and a DC voltage -100V is applied from the power supply 21 while the conductive member 19 is driven to rotate, and the current flowing out from the cylindrical metal 20 is applied. Measure with an ammeter 22. The electric resistance of the conductive member is calculated from the applied voltage and the measured current at this time. In the examples described later, a force of 5N is applied to both ends of the conductive substrate 1 of the conductive member 19 to bring the cylindrical metal 20 into contact with the cylindrical metal 20 having a diameter of 30 mm, and the cylindrical metal 20 is rotated at a peripheral speed of 150 mm / s. I let you.

[Electrophotograph process cartridge]
The electrophotographic process cartridge according to the present invention (hereinafter, also referred to as a process cartridge) has a conductive member according to the present invention. In the process cartridge, the conductive member according to the present invention can be used as a developing roller, a charging roller, and the like.

FIG. 2 shows a schematic configuration of an example of a process cartridge according to the present invention. As a developing method, a contact developing method using a non-magnetic one-component toner or the like is adopted. The process cartridge shown in FIG. 2 is provided with a toner container containing the toner 10 and a developing roller 4 that is rotationally driven in the direction of the arrow so as to close the opening of the toner container. Further, at the same time that the toner on the developing roller 4 is triboelectrically charged, a toner regulating member 8 for controlling the amount of toner to form a thin layer of toner is provided in contact with the developing roller 4. Further, in order to prevent toner from leaking from both ends of the developing roller 4, end sealing members (not shown) are provided on the toner container in contact with both ends of the developing roller 4.

In the toner container, the toner 10 is supplied to the developing roller 4, and at the same time, the toner supply roller 7 which is rotationally driven in the direction of the arrow is developed in order to scrape off the toner remaining unused on the developing roller 4 after development. It is provided in contact with the roller 4. Further, in order to stir the toner 10 and supply it to the toner supply roller 7, a blade-shaped toner stirring member 9 that is rotationally driven in the direction of the arrow is provided. The toner regulating member 8 is arranged in contact with the developing roller 4 at a predetermined contact pressure in a state where the leaf spring made of SUS is coated with an elastic resin layer and bent within the elastic range. .. The toner supply roller 7 is an elastic roller made of a conductive sponge, and is arranged so as to penetrate the developing roller 4. The process cartridge has a configuration in which a cleaning container having a charging roller 6 and a photoconductor drum 5 is arranged in contact with the developing roller 4 and the photoconductor drum 5 with a constant stress.

[Electrophotograph image forming apparatus]
The electrophotographic image forming apparatus according to the present invention (hereinafter, also referred to as an image forming apparatus) has a conductive member according to the present invention. FIG. 3 shows an example of the image forming apparatus according to the present invention equipped with the process cartridge according to the present invention.

The image forming apparatus 11 is a color laser printer using a transfer type electrophotographic process, a contact charging method, a one-component contact developing method, or the like. The image forming apparatus 11 forms a full-color image on a transfer material 13 as a recording medium, for example, paper, an OHP sheet, or the like according to image information from an external host apparatus (not shown) connected communicatively, and outputs the image. can do.

Further, the image forming apparatus 11 is a quadruple drum system (in-line system) image forming apparatus for obtaining a full-color printed image. That is, the image forming apparatus 11 has a plurality of image forming units serving as image forming means, that is, an image forming unit for forming an image of each color of yellow (Ye), magenta (Mg), cyan (Cy), and black (Bk). There is. The image formed by each image forming unit is once multiple-transferred onto the intermediate transfer belt 12 as the intermediate transfer body, and then collectively transferred onto the transfer material 13 as a recording medium such as paper. The intermediate transfer belt 12 is suspended and driven by a drive roller and a support roller.

The image forming unit of each color has the same configuration, and includes a photoconductor drum 5 as an image carrier for supporting a rotationally driven electrostatic latent image. A charging roller 6 as a charging means and a laser beam scanner device 14 as an exposure means are arranged around the photoconductor drum 5 to form an electrostatic latent image on the photoconductor drum 5. A process cartridge as a developing means is further arranged around the photoconductor drum 5, and an electrostatic latent image formed on the photoconductor drum 5 is developed into a visible image (toner image). Further, a cleaning device (not shown) as a cleaning means for cleaning the residual toner image on the photoconductor drum 5 is arranged around the photoconductor drum 5.

The photoconductor drum 5, the charging roller 6, and the cleaning device constituting each image forming unit may be integrally configured as a process cartridge. Each process cartridge is attached to and detached from the main body of the image forming apparatus 11 via a mounting means. Therefore, when the process cartridge reaches the end of its life due to toner consumption, the image forming portion, that is, the process cartridge can be replaced.

The photoconductor drum 5 is uniformly charged by the charging roller 6 for charging the image carrier in each image forming unit, and the laser beam scanner device 14 for forming an electrostatic latent image on the charged surface is used from the controller. A latent image is formed according to the input signal. The electrostatic latent image is developed with toner and visualized as a toner image in the process cartridge. This image formation process is performed for each color.

The toner image of each color is transferred onto the intermediate transfer belt 12 at the primary transfer unit in which the primary transfer roller 15 as a transfer means is arranged, and a color image is formed on the intermediate transfer belt 12. This color image is collectively transferred onto the transfer material 13 at the secondary transfer unit in which the secondary transfer roller 16 as the secondary transfer means is arranged. The transfer material 13 is transferred from the paper feed cassette to the secondary transfer unit provided with the secondary transfer roller 16 by the transfer means of the transfer roller 17. The transfer material 13 to which the color image is transferred is conveyed to the fixing device 18, is fixed by the fixing device 18, and then discharged. On the other hand, the transfer residual toner remaining on the photoconductor drum 5 after transfer is cleaned by the cleaning device.

Hereinafter, the present invention will be described in detail based on Examples and Comparative Examples.

<Carbon black>
The carbon blacks used in this example and comparative examples are shown in Table 1 below.

＜シラン化合物＞
本実施例及び比較例で使用するシラン化合物を以下の表２に記す。

<Silane compound>
The silane compounds used in this example and comparative examples are shown in Table 2 below.

<Polyol>
(Polyol 1)
In the reaction vessel, a mixture of 144.2 g of dry tetrahydrofuran and 172.2 g of dry 3-methyltetrahydrofuran (molar ratio 50:50) was maintained at a temperature of 10 ° C. Tetrahydrofuran is a raw material that provides a structure represented by the following formula (5) by ring-opening polymerization. Further, 3-methyltetrahydrofuran is a raw material that provides a structure represented by the following formula (6) and a structure represented by the following formula (7) by ring-opening polymerization. Next, 13.1 g of a 70 mass% perchloric acid aqueous solution and 120 g of acetic anhydride were added, and the reaction was carried out for 2.5 hours. Next, the reaction mixture was poured into 600 g of a 20 mass% sodium hydroxide aqueous solution for purification. Further, the residual water and solvent components were removed under reduced pressure to obtain polyol 1 which is a liquid polyether diol. The number average molecular weight of the obtained polyol 1 was 2000.

ポリオール１は、前記式（５）で示される構造と、前記式（６）で示される構造および前記式（７）で示される構造の少なくとも一方の構造とを有していた。前記式（５）で示される構造の総数と、前記式（６）で示される構造および前記式（７）で示される構造の合計総数との比は５０：５０であった。

The polyol 1 had a structure represented by the formula (5), a structure represented by the formula (6), and at least one of the structures represented by the formula (7). The ratio of the total number of structures represented by the formula (5) to the total total number of structures represented by the formula (6) and the structure represented by the formula (7) was 50:50.

(Polyol 2)
In the reaction vessel, 947.9 g of ε-caprolactone, 0.010 g (10 ppm) of tin octylate (trade name: "Stannoct", manufactured by API Corporation), and 52.1 g of neopentyl glycol as a polymerization initiator were added. I prepared it. Then, at a temperature of 150 ° C., the remaining ε-caprolactone was reacted until it became 1% by mass or less by gas chromatography analysis to obtain polyol 2, which is a polyester diol represented by the following formula (8). The number average molecular weight Mn of the obtained polyol 2 was 2000.

（ポリオール３）
反応容器中で、３−メチル−１，５−ペンタンジオール２３６．４ｇにジエチルカーボネート２２４．５ｇを加え、２００℃に加熱した。次に、エチレングリコール及び水を除去し、さらに真空下で縮合反応を進めて、下記式（９）で示されるポリカーボネートジオールであるポリオール３を得た。得られたポリオール３の数平均分子量は２０００であった。

(Polyol 3)
In the reaction vessel, 224.5 g of diethyl carbonate was added to 236.4 g of 3-methyl-1,5-pentanediol and heated to 200 ° C. Next, ethylene glycol and water were removed, and the condensation reaction was further carried out under vacuum to obtain polyol 3, which is a polycarbonate diol represented by the following formula (9). The number average molecular weight of the obtained polyol 3 was 2000.

＜イソシアネート化合物＞
（イソシアネート化合物１）
窒素雰囲気下、反応容器中でコスモネートＭＤＩ（商品名、三井化学（株）製）７６．５ｇに対し、２００．０ｇのポリオール１を、反応容器内の温度を６５℃に保持しつつ徐々に滴下した。滴下終了後、温度６５℃で２時間反応させた。得られた反応混合物を室温まで冷却し、イソシアネート基含有量３．８質量％のイソシアネート基末端ウレタンプレポリマーであるイソシアネート化合物１を得た。

<Isocyanate compound>
(Isocyanate compound 1)
Under a nitrogen atmosphere, 200.0 g of polyol 1 was gradually added to 76.5 g of cosmonate MDI (trade name, manufactured by Mitsui Chemicals, Inc.) in the reaction vessel while maintaining the temperature inside the reaction vessel at 65 ° C. Dropped. After completion of the dropping, the reaction was carried out at a temperature of 65 ° C. for 2 hours. The obtained reaction mixture was cooled to room temperature to obtain isocyanate compound 1 which is an isocyanate group-terminated urethane prepolymer having an isocyanate group content of 3.8% by mass.

(Isocyanate compound 2)
An isocyanate compound 2 which is an isocyanate group-terminated prepolymer having an isocyanate group content of 3.9% by mass was obtained in the same manner as the isocyanate compound 1 except that the polyol 1 was changed to the polyol 3.

<Ion conductive agent>
The ionic conductive agent represented by the formula (3) was designated as the ionic conductive agent 1, and the ionic conductive agent represented by the formula (10) was designated as the ionic conductive agent 2.

<Preparation of coated carbon black 1-27>
The following materials were blended in a container.
・ Carbon black 1 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 100g
・ Silane compound 1 ・ ・ ・ ・ ・ 1g
・ Methyl ethyl ketone (solvent) ・ ・ ・ ・ ・ ・ ・ 1000g
This was dispersed in a sand mill filled with 80% by mass of glass beads having a particle size of 1.5 mm at a peripheral speed of 4 m / s for 1 hour. The obtained slurry was filtered, washed with methyl ethyl ketone, washed, and dried at 100 ° C. for 2 hours to obtain coated carbon black (hereinafter referred to as "coated carbon black 1") with silane compound 1. 80 g of coated carbon black 1 was placed in a beaker (capacity 2000 ml) containing 1000 ml of ethanol and stirred with a stirring blade having a diameter of 6 cm (200 rpm, 1 hour). Then, the coated carbon black 1 was filtered off, dried at 100 ° C. for 2 hours, and then the peak showing the −NH bond derived from the silane compound was found on the surface of the coated carbon black 1 by the IR measurement by the ATR method. I confirmed that it exists. From this, it was confirmed that at least one of the hydroxyl groups derived from the three methoxy groups of the silane compound 1 reacted with the surface functional group of the carbon black 1 and was bonded.

Coated carbon blacks 2 to 27 were produced in the same manner as in coated carbon black 1 except that the types and amounts of carbon black and silane compounds were combined in Table 3 below. For each coated carbon black, the presence or absence of bonding with the silane compound was confirmed in the same manner as in the above-mentioned coated carbon black 1. Then, when a peak indicating the presence of a bond derived from the silane compound was confirmed on the surface of the coated carbon black after the stirring treatment, it was determined to be "bonded", and when it could not be confirmed, it was determined to be "no bond".

<Conductive substrate, elastic layer>
A conductive substrate was prepared by subjecting the surface of a cylindrical free-cutting steel having an outer diameter of 6 mm and a total length of 270 mm to industrial nickel plating having a thickness of 6 μm. An adhesive (trade name: DY39-012, manufactured by Toray Dow Corning Silicone Co., Ltd.) for adhering silicone and metal to the conductive substrate was applied to a thickness of 3 μm. This was fired at 150 ° C. for 30 minutes and then cooled to room temperature to obtain an adhesive-coated conductive substrate. Next, the adhesive-coated conductive substrate was placed in a cylindrical mold having an inner diameter of 10 mm so as to be concentric with the cylindrical mold. Next, in the cylindrical mold, liquid conductive silicone rubber (trade name: DY35-2059N, manufactured by Toray Dow Corning Silicone Co., Ltd., ASKER-C hardness 40 degrees, volume resistivity 1 × 10) was used as the material of the elastic layer. ⁵ Ω · cm) was cast. Then, it was placed in an oven at a temperature of 130 ° C., heat-molded for 20 minutes, demolded, and an elastic layer having a thickness of 2 mm was formed around the conductive substrate.

<Resin particles>
Urethane resin particles (trade name: C600 transparent, diameter 10 μm, manufactured by Negami Kogyo Co., Ltd.) were used to roughen the surface of the conductive member.

[Example 1]
Each of the following ingredients was blended in a 450 ml mayonnaise bottle.
・ Coated carbon black 1 ・ ・ ・ ・ ・ ・ ・ ・ 2.0g
・ Polyol 1 ・ ・ ・ ・ ・ ・ 20g
・ Isocyanate compound 1 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 45g
・ Ion conductive agent 1 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.10g
・ Resin particles ・ ・ ・ ・ ・ ・ ・ ・ ・ 2.0g
・ Methyl ethyl ketone ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 150g
・ Zirconia beads with a particle size of 0.5 mm ・ ・ ・ ・ ・ ・ 200 g
This was dispersed with a paint shaker for 4 hours and then filtered through a # 200 nylon mesh to obtain a paint for a conductive surface layer. The coating material for the conductive surface layer was vertically immersed and coated on the conductive substrate on which the elastic layer was formed. The average coating speed was 500 mm / min. After air-drying at room temperature for 5 minutes, it was dried / baked in an oven at 150 ° C. for 1 hour and 30 minutes. Then, the ends of the elastic layer and the conductive surface layer, which had been provided with a cutting allowance of 5 mm in advance, were cut off to obtain a conductive member.

<Evaluation>
(Volume resistivity of paint film for conductive surface layer)
The volume resistivity of the coating film for the conductive surface layer was measured by the method described above. The results are shown in Table 5.

(Surface roughness Ra of conductive member)
The surface roughness Ra of the conductive member was measured by a contact type surface roughness meter (trade name: Surfcoder SE3500, manufactured by Kosaka Laboratory Co., Ltd.). The measurement uses a diamond contact needle with a tip radius of 2 μm and an apex angle of 90 degrees, and according to JIS B0601-1982, the measurement length is 4 mm, the measurement speed is 0.1 mm / s, the cutoff value is 0.8 mm, the preliminary length is 1 times, and the filter is used. It was performed under the condition of 2CR. As a method of calculating the measured value, a total of 6 points are measured at 3 points in the axial direction and 2 points in the circumferential direction of the conductive member, and the average value obtained by averaging the measured values of each measurement is the surface roughness of the conductive member. The value was Ra. The results are shown in Table 5.

(Electrical resistance of conductive members)
First, the obtained conductive member was left in an N / N environment for 12 hours, and then the electrical resistance was measured according to the method for measuring the electrical resistance of the conductive member described above. Next, the conductive member was mounted as a developing roller on a laser printer as an electrophotographic apparatus. Then, an image was output using this laser printer. A developing voltage of −350 V was applied to the developing roller. As the image pattern, a halftone image (an image in which a horizontal line having a width of 1 dot and an interval of 2 dots is drawn in the direction perpendicular to the rotation direction of the photoconductor) and a solid white image were used. The density of the halftone image was measured with an X-rite densitometer. Moreover, the fog of the solid white image was measured by the PHOTOBOLT fog meter.

Next, using the laser printer, 15,000 consecutive patterns for repeatedly drawing horizontal lines having a width of 2 dots and an interval of 98 dots were output. Then, the conductive member was taken out from the laser printer, washed by injecting high-pressure ion-exchanged water with a high-pressure water washer, and drained by blowing high-pressure dry air.

Next, the drained conductive member was attached to the laser printer again, and the laser printer was used to continuously output 15,000 patterns for repeatedly drawing horizontal lines having a width of 2 dots and an interval of 98 dots. Then, under the same environment, a halftone image and a solid white image were output, and the density of the halftone image and the fog of the solid white image were measured. Next, the conductive member was taken out from the laser printer again, washed by injecting high-pressure ion-exchanged water with a high-pressure water washer, and drained by blowing high-pressure dry air. After the drained conductive member was left in the N / N environment again for 12 hours, the electric resistance was measured according to the above-mentioned method for measuring the electric resistance of the conductive member. The smaller the rate of increase in electrical resistance from the initial stage to the end of durability, the better. The results are shown in Table 5.

(Halftone image density)
As an image evaluation, it was confirmed whether or not the image deterioration due to the energization deterioration was suppressed when the above-mentioned durability was performed and the final image was drawn. Regarding the halftone image density, the difference between the initial value and the endurance value is important in practical use. When the difference between the initial value and the value after durability is 0.05 or less, it is very good. When the difference is more than 0.05 and 0.09 or less, it is good. When the difference exceeds 0.09 and is 0.12 or less, the density change is recognized, but it does not matter when the image is output normally, and there is no problem in practical use. When the difference exceeds 0.12, the concentration change is so large that it is not suitable for practical use. The results are shown in Table 5.

(Cover of solid white image)
As for the fog of the solid white image, it is preferable that the ratio is small. When the ratio after durability is 2.0% or less, it is very good. When the ratio exceeds 2.0% and is 2.5% or less, it is good and does not matter in practical use. When the ratio is more than 2.5% and 4.0% or less, it is within the practical range as can be seen by carefully observing the image. When the ratio exceeds 4.0%, the fog is so large that it is not suitable for practical use. The results are shown in Table 5.

[Examples 2 to 14, Comparative Examples 1 to 9]
A conductive member was produced and evaluated in the same manner as in Example 1 except that the type of coated carbon black in Example 1 was changed as shown in Table 4 below. The results are shown in Table 5.

In each of the conductive members of Examples 1 to 14, the amount of increase in the halftone image density was 0.12 or less, and there was no problem in practical use. In addition, the fog value of the solid white image after durability was 2.5% or less, and there was no problem in practical use. Since the resistance increase of the conductive member was less than two orders of magnitude, it is considered that the suppression of the resistance increase due to durability contributed to the maintenance of image quality. The reason why the increase in resistance is suppressed is that the silane compound bonded to the surface of carbon black and the urethane resin which is a binder are bonded to form a group represented by the above formula (1), which is electronically conductive and ionic conductive. It is considered that both were maintained to suppress the deterioration of energization. Since all of the silane compounds used in Examples 1 to 14 have a reactive group that forms the group represented by the formula (1), the group represented by the formula (1) can be formed. It was. On the other hand, in each of the conductive members of Comparative Examples 1 to 9, the increase amount of the halftone image density exceeds 0.12, and the fog value of the solid white image after durability also exceeds 4%. It did not endure practical use. It is considered that this is because the bond between the carbon black and the silane compound is so small that it cannot be measured by the ATR method IR, and the carbon black and the urethane resin which is the binder are not bonded by the group represented by the above formula (1). Be done. That is, carbon black moves in the urethane resin in the conductive surface layer under repeated stress and energization, the electron conductive mechanism is disrupted, and there is no group that suppresses the polarization of the ionic conductive agent, so that the ionic conductive agent is polarized. It is probable that it has been done.

[Examples 15 to 25]
A conductive member was produced and evaluated in the same manner as in Example 1 except that the types of coated carbon black, polyol, isocyanate compound and ionic conductive agent in Example 1 were changed as shown in Table 6 below. The results are shown in Table 7.

実施例１５から実施例２５の導電性部材では、いずれもハーフトーン画像濃度の増加量が０．０５以下であり、非常に良好であった。また、耐久後のベタ白画像のかぶりの値も２．５％以下であり、実用上問題なかった。導電性部材の抵抗上昇が２桁以下であったため、耐久による抵抗上昇の抑制が画像品質の維持に貢献したと考えられる。抵抗上昇が抑制された理由として、カーボンブラック表面に結合したシラン化合物と、バインダであるウレタン樹脂とが結合して前記式（１）で示される基を形成し、電子導電性とイオン導電性の両方を維持して通電劣化を抑制したと考えられる。実施例１５から実施例２５の導電性部材の検討では、ポリオールやイソシアネート化合物、イオン導電剤の種類を変更したが、前記式（１）で示される基が形成されたため、いずれも良好な性能を示した。

In each of the conductive members of Examples 15 to 25, the amount of increase in the halftone image density was 0.05 or less, which was very good. In addition, the fog value of the solid white image after durability was 2.5% or less, and there was no problem in practical use. Since the resistance increase of the conductive member was less than two orders of magnitude, it is considered that the suppression of the resistance increase due to durability contributed to the maintenance of image quality. The reason why the increase in resistance is suppressed is that the silane compound bonded to the surface of carbon black and the urethane resin which is a binder are bonded to form a group represented by the above formula (1), which is electronically conductive and ionic conductive. It is considered that both were maintained to suppress the deterioration of energization. In the examination of the conductive members of Examples 15 to 25, the types of the polyol, the isocyanate compound, and the ionic conductive agent were changed, but since the group represented by the above formula (1) was formed, all of them had good performance. Indicated.

[Example 26]
Each of the following ingredients was blended in a 450 ml mayonnaise bottle.
・ Carbon black 1 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 2.0g
・ Polyol 1 ・ ・ ・ ・ ・ ・ 20g
・ Isocyanate compound 1 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 45g
・ Ion conductive agent 1 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.10g
・ Resin particles ・ ・ ・ ・ ・ ・ ・ ・ ・ 2.0g
・ Silane compound 1 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.02g
・ Methyl ethyl ketone ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 150g
・ Zirconia beads with a particle size of 0.5 mm ・ ・ ・ ・ ・ ・ 200 g
This was dispersed with a paint shaker for 4 hours and then filtered through a # 200 nylon mesh to obtain a paint for a conductive surface layer. This was applied in the same manner as in Example 1, dried, and then cut to obtain a conductive member. The conductive member was evaluated in the same manner as in Example 1. The results are shown in Table 12.

[Examples 27 to 31]
A conductive member was prepared and evaluated in the same manner as in Example 26, except that the types of carbon black and silane compounds in Example 26 were changed as shown in Table 8 below. The results are shown in Table 12.

[Comparative Example 10 to Comparative Example 12]
Coated carbon black 28 to 30 was obtained in the same manner as in coated carbon black 1 except that the compounds shown in Table 9 and Table 10 below were used as the silane compound. A conductive member was produced and evaluated in the same manner as in Example 1 except that the type of coated carbon black in Example 1 was changed as shown in Table 11 below. The results are shown in Table 12.

In each of the conductive members of Examples 26 to 31, the amount of increase in the halftone image density was 0.12 or less, and there was no problem in practical use. In addition, the fog value of the solid white image after durability was 4.0% or less, which was within the practical range. Since the resistance increase of the conductive member was less than two orders of magnitude, it is considered that the suppression of the resistance increase due to durability contributed to the maintenance of image quality. The reason why the increase in resistance is suppressed is that the silane compound bonded to the surface of carbon black and the urethane resin which is a binder are bonded to form a group represented by the above formula (1), which is electronically conductive and ionic conductive. It is considered that both were maintained to suppress the deterioration of energization. In Examples 26 to 31, instead of reacting the silane compound with carbon black in advance, the silane compound is blended together when the coating material is dispersed, and carbon black and urethane are mixed in the process of forming the conductive surface layer. It was reacted with the resin at the same time. It is considered that the reaction rate is lower than that of the reaction in advance as in Example 1, but it is considered that the silane compound was bonded to the carbon black and the urethane resin in the process of forming the conductive surface layer. It is considered that the silane compounds used in Examples 26 to 31 formed the group represented by the above formula (1) in the process of forming the conductive surface layer by blending at the time of coating coating, and the conductivity of the conductive member. It is considered that it contributed to the maintenance of the rate. On the other hand, in each of the conductive members of Comparative Examples 10 to 12, the increase amount of the halftone image density exceeds 0.12, and the fog value of the solid white image after durability also exceeds 4%. It did not endure practical use. It is considered that this is because although the carbon black and the silane compound are bonded, the silane compound has no portion to be bonded to the urethane resin, and the group represented by the above formula (1) is not formed in the process of forming the conductive surface layer. Be done. Since carbon black and urethane resin, which is a binder, are not bonded by the group represented by the above formula (1), the effects of maintaining the electron conductive mechanism for suppressing conduction deterioration and suppressing the polarization of the ionic conductive agent could not be obtained. Conceivable. That is, carbon black moves in the urethane resin in the conductive surface layer under repeated stress and energization, the electron conductive mechanism is disrupted, and there is no group that suppresses the polarization of the ionic conductive agent, so that the ionic conductive agent is polarized. It is probable that the resistance increased significantly because it had been done.

[Examples 32 to 39]
A conductive member was produced and evaluated in the same manner as in Example 1 except that the types and blending amounts of the coated carbon black and the ionic conductive agent in Example 1 were changed as shown in Table 13 below. The results are shown in Table 14.

実施例３２から３５では、シラン化合物によるコート量を変更したコート済みカーボンブラックを用いて評価を行った。実施例３６から３９では、コート済みカーボンブラックとイオン導電剤の配合量を変更して評価を行った。実施例３２から実施例３９では、ハーフトーン画像濃度の上昇量、ベタ白画像のかぶり共に実用に足る評価結果が得られた。これらの実施例の導電性部材は前記式（１）で示される基を有するため、各材料の配合量を変更しても実用に足る導電性部材が得られた。

In Examples 32 to 35, evaluation was performed using coated carbon black in which the amount of coating with the silane compound was changed. In Examples 36 to 39, the evaluation was performed by changing the blending amounts of the coated carbon black and the ionic conductive agent. In Examples 32 to 39, practical evaluation results were obtained for both the amount of increase in the halftone image density and the fog of the solid white image. Since the conductive members of these examples have a group represented by the above formula (1), a conductive member sufficient for practical use was obtained even if the blending amount of each material was changed.

1 Conductive substrate 2 Elastic layer 3 Conductive surface layer

Claims (6)

An electrophotographic conductive member having a conductive substrate, an elastic layer on the conductive substrate, and a conductive surface layer on the elastic layer.
The conductive surface layer is
i) Urethane resin and
ii) Carbon black and
iii) Ion conductive agent and
Contains,
The urethane resin is not covalently bonded to the ionic conductive agent and is not covalently bonded.
The carbon black is a conductive member for electrophotographic photography, which is bonded to the urethane resin via a structure represented by the following formula (1):

(In the formula (1), R ₁ represents an alkylene group having 1 to 6 _{carbon atoms. R 2} represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an aminoalkyl group having 1 to 4 carbon atoms or a phenyl group. ^* 1-1, * 1-2, and * 1-3 independently indicate any of the bonding sites with the carbon black, the bonding site with the hydrogen atom, and the bonding site with the silicon atom, ^* 1 At least one of -1, * 1-2 and * 1-3 is a bonding site with the carbon black. ^* 2 indicates a bonding site with the urethane resin). An electrophotographic conductive member having a conductive substrate, an elastic layer on the conductive substrate, and a conductive surface layer on the elastic layer.
The conductive surface layer is
iv) Acid carbon black and
v) The compound represented by the following formula (2) and
vi) Polyol and
vii) Isocyanate compound and
viii) An ionic conductive agent that does not covalently bond with the polyol and the isocyanate compound,
An electrophotographic conductive member comprising a crosslinked product of a mixture containing:

(In the formula (2), R ₃ represents an alkylene group having 1 to 6 _{carbon atoms. R 4} represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an aminoalkyl group having 1 to 4 carbon atoms or a phenyl group. . R ₅ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.) The electrophotographic conductive member according to claim 2, wherein the pH value of the acidic carbon black is 4.5 or less, which is measured according to JIS K 5101-172: 2004. The electrophotographic conductive member according to any one of claims 1 to 3, wherein the ionic conductive agent is an ionic conductive agent represented by the following formula (3).

An electrophotographic process cartridge having the electrophotographic conductive member according to any one of claims 1 to 4. An electrophotographic image forming apparatus having the electrophotographic conductive member according to any one of claims 1 to 4.

Images