JP2012181370A - Developing roller, process cartridge and electrophotographic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing roller that has stable electrical characteristics for a long period and suppresses blade bias leak.SOLUTION: The elastic layer of a developing roller contains a copolymer comprising quaternary pyridinium salt and tertiary amine.

Description

The present invention relates to a developing roller, an electrophotographic process cartridge (hereinafter referred to as “process cartridge”), and an electrophotographic apparatus.

  In an electrophotographic apparatus, a developing roller used for contact development includes a metal shaft core and an elastic layer (hereinafter, “silicone rubber” made of a cured product of a silicone rubber composition in which a conductive material is dispersed on its peripheral surface. A structure provided with an "elastic layer" is often used. This is because the elastic layer has excellent flexibility, and can reduce deterioration and wear of a contact member such as toner, a photosensitive drum, or a toner amount regulating blade.

  By the way, in recent years, a method has been proposed in which a bias voltage is applied to the toner amount regulating blade so that the toner can be efficiently frictionally charged and a stable toner layer can be formed on the developing roller (Patent Document 1). ). Therefore, more uniform electrical characteristics are required for the developing roller, and an ion conductive material is often used as a conductive material dispersed on the developing roller.

  In Patent Document 2, an ion conductive agent such as an alkali metal peroxide such as lithium peroxide, a quaternary ammonium salt, or a quaternary phosphonium salt is used as an elastic material in order to make the electric resistance values in the axial direction and circumferential direction of the charging roller uniform. Is disclosed. It is disclosed that leakage or damage to the photosensitive drum is suppressed by dispersing an alkali metal peroxide or an ionic conductive material. Further, Patent Document 3 has an effect of suppressing a change in resistance at the pressure contact portion of the developing roller by adding an oil-based ion conductive material to the elastic layer in the developing roller whose elastic layer is made of silicone rubber. It is disclosed. Further, Patent Document 4 discloses that density unevenness, insufficient gradation, and ghost are suppressed by adding a quaternary ammonium salt to the outermost surface layer of the developing roller.

JP 2000-112212 A Japanese Patent Laid-Open No. 9-101652 JP 2005-164784 A JP 2003-15403 A

  However, according to the study by the present inventors, the developing roller having a silicone rubber elastic layer made conductive by using an ionic conductive material has a large change in electric resistance with long-term use, and imparts triboelectric charge to the developer. May change significantly. This is presumably because the intermolecular cohesive force is small because the intermolecular force of the silicone rubber is small, and the movement of the cation species and anion species of the ionic conductive material during energization is intense.

  Accordingly, an object of the present invention is to provide a developing roller that is flexible and has little change with time in the triboelectric chargeability of the developer.

The present invention has a shaft core, an elastic layer, and a surface layer in this order, and the elastic layer is one or both selected from the group consisting of silicone rubber and the following structural formula (1) and the following structural formula (2) And a developing roller comprising a copolymer having a structural unit represented by the following structural formula (3):

(In Structural Formulas (1) to (3), R ₁ and R ₂ each independently represents an alkyl group having 1 to 13 carbon atoms, R ₃ represents a hydrogen atom or a methyl group, and R ₄ represents a carbon number. 2 to 4 alkylene groups, R ₅ and R ₆ each independently represents an alkyl group having 1 to 2 carbon atoms, X ₁ ^- and X ₂ ^- represent anionic species)

A process cartridge according to the present invention is a process cartridge that is detachably attached to a main body of an electrophotographic apparatus, and the built-in developing roller is the above-described developing roller.
The electrophotographic apparatus according to the present invention is an electrophotographic apparatus having a photosensitive drum and a developing roller disposed in contact with the photosensitive drum, wherein the developing roller is the developing roller described above. To do.

According to the present invention, it is possible to obtain a developing roller in which the triboelectric chargeability to the developer hardly changes with time.

It is sectional drawing of an example of the developing roller of this invention. FIG. 2 is a schematic diagram illustrating an example of a process cartridge and an electrophotographic apparatus on which the developing roller of the present invention is mounted. It is a schematic diagram which shows an example of the liquid circulation type dip coating apparatus applicable in order to form the surface layer of the developing roller of this invention.

A cross-sectional view of an example of the developing roller of the present invention is shown in FIG.
The developing roller 1 of the present invention usually has a shaft core 11 formed of a conductive material such as metal, has at least one elastic layer 12 on the outer peripheral surface, and further has at least one layer on the outer peripheral surface. The surface layer 13 is laminated.

<Shaft core body 11>
The shaft core body 11 has a columnar shape in the figure, but the shaft core body may have a hollow cylindrical shape.
The developing roller 1 is generally used with an electrical bias applied or grounded. Therefore, the shaft core 11 is a support member, and at least the surface is conductive as a conductive material. Therefore, the shaft core 11 is made of a conductive material sufficient to apply a predetermined voltage to the elastic layer 12 having at least an outer peripheral surface formed thereon. Specific examples of the configuration of the shaft core include the following.
A shaft core made of a metal or alloy such as Al, Cu alloy, SUS;
-Iron shaft core with Cr or Ni plating on the surface;
-Synthetic resin shaft core with Cr or Ni plating on the surface.
In the developing roller used in the electrophotographic apparatus, it is appropriate that the shaft core 11 has an outer diameter in the range of 4 mm to 10 mm.

<Elastic layer 12>
The elastic layer 12 has silicone rubber, one or both structural units selected from the group consisting of the following structural formula (1) and the following structural formula (2), and a structural unit represented by the following structural formula (3). The elastic layer is made conductive by the copolymer including the copolymer.
Here, the silicone rubber is preferably polydimethylsiloxane, polymethyltrifluoropropylsiloxane, polymethylvinylsiloxane, polyphenylvinylsiloxane, or a copolymer of these siloxanes from the viewpoint of shape stability during molding.

In Structural Formulas (1) to (3), R ₁ and R ₂ each independently represent an alkyl group having 1 to 13 carbon atoms, R ₃ represents a hydrogen atom or a methyl group, and R ₄ represents 2 carbon atoms. An alkylene group having 4 or less is shown, and R ₅ and R ₆ are each independently an alkyl group having 1 to 2 carbon atoms. X ₁ ^- and X ₂ ^- represent anionic species.
Next, the copolymer component (1), copolymer component (2) and copolymer component (3) comprising the above structural formula (1), structural formula (2) and structural formula (3) constituting the copolymer This will be specifically described.

  The copolymer component (1) composed of the structural formula (1) and the copolymer component (2) composed of the structural formula (2) have a pyridinium group and have a cationic structure. Specific monomers for forming such a structure include 1-methyl-2-vinylpyridinium haloid, 1-ethyl-2-vinylpyridinium haloid, 1-propyl-2-vinylpyridinium haloid, 1-butyl- 2-vinylpyridinium haloid, 1-pentyl-2-vinylpyridinium haloid, 1-hexyl-2-vinylpyridinium haloid, 1-heptyl-2-vinylpyridinium haloid, 1-octyl-2-vinylpyridinium haloid 1-nonyl-2-vinylpyridinium haloid, 1-decyl-2-vinylpyridinium haloid, 1-dodecyl-2-vinylpyridinium haloid, 1-tridecyl-2-vinylpyridinium haloid, 1-methyl-2 -Vinylpyridinium p-toluenesulfonate, 1-ethyl-2 Vinylpyridinium paratoluenesulfonate, 1-propyl-2-vinylpyridinium paratoluenesulfonate, 1-butyl-2-vinylpyridinium paratoluenesulfonate, 1-pentyl-2-vinylpyridinium paratoluenesulfonate, 1-hexyl-2-vinylpyridinium p-toluenesulfonate, 1-heptyl-2-vinylpyridinium p-toluenesulfonate, 1-octyl-2-vinylpyridinium p-toluenesulfonate, 1-nonyl-2-vinylpyridinium Paratoluenesulfonate, 1-decyl-2-vinylpyridinium paratoluenesulfonate, 1-dodecyl-2-vinylpyridinium paratoluenesulfonate, 1-tridecyl-2-vinylpyridinium paratoluenesulfonate, and the like. It is.

The copolymer component (3) comprising the structural formula (3) has a tertiary amine structure.
Specific monomers forming such a structure include N, N-dimethylaminomethyl (meth) acrylate, N, N-diethylaminomethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-diethylaminopropyl (meth) acrylate, N, N-dimethylaminobutyl (meth) acrylate, N, N-diethylaminobutyl (Meth) acrylate etc. are mentioned. "(Meth) acrylate" means methacrylate or acrylate (hereinafter the same).

  The copolymer shown in the present invention may be copolymerized with another monomer in addition to the above-mentioned pyridinium group-containing monomer and tertiary amino group-containing monomer. Specific monomers include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, tert-butyl (meth) acrylate, iso-butyl (meth) acrylate, n -Amyl (meth) acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, iso-octyl (meth) acrylate, n-nonyl (meth) ) Acrylate, n-lauryl (meth) acrylate, 2,2,2-trifluoroethyl (meth) acrylate, 2- (perfluorobutyl) ethyl (meth) acrylate, 2- (perfluorohexyl) ethyl (meth) acrylate , 2- (P Perfluorooctyl) ethyl (meth) such as methacrylic acid alkyl esters of (meth) acrylic acid alkyl ester as the acrylate. These monomers can be appropriately used for adjusting the polarity of the copolymer.

  The copolymerization ratio of these monomers and the addition amount of the copolymer are not particularly limited, and can be set as necessary. That is, as the abundance ratio of the copolymer component (1) and / or the copolymer component (2) increases, the electrical resistance value of the added developing roller decreases. This is because the copolymerization component (1) and / or the copolymerization component (2) contributes to electrical conductivity as a carrier.

  Further, when the abundance ratio of the copolymer component (3) is increased, the electric characteristics of the developing roller are stable even when used for a long time. This has a high affinity between the tertiary amino group contained in the copolymer component (3) and the low molecular weight component silicone oil contained in the silicone rubber. Therefore, when a voltage is applied to the developing roller, the movement of the copolymer component (1) and / or copolymer component (2) which is a cation can be suppressed.

Preferably, the polymerization ratio of the pyridinium group-containing monomer as the copolymer component (1) and / or (2) is 20 mol% or more and 80 mol% or less, and the degree of polymerization of the tertiary amino group-containing monomer as the copolymer component (3) Is 20 mol% or less.
The content of the copolymer is preferably 0.2 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the silicone rubber contained in the elastic layer 12 from the viewpoint of electrical characteristics required for the developing roller. The weight average molecular weight (Mw) of the copolymer is preferably 10,000 or more and 100,000 or less from the viewpoint of productivity or dispersibility in silicone rubber.

  As described above, by using the silicone rubber containing the copolymer component (1) and / or the copolymer composed of the copolymer component (2) and the copolymer component (3) as the elastic layer 12, a long time can be obtained. It is possible to maintain stable electrical characteristics across the entire area. Moreover, since it has ionic conductivity, an effect of suppressing blade bias leakage can be obtained in order to exhibit uniform electrical characteristics. As a result, a high-quality image can be formed over a long period of time.

Here, anionic species X ₁ which copolymer component (1) and / or copolymer component (2) has ^- is preferably is fluorine ions and / or chloride ions ^- and X _2. This is because the so-called ghost can be suppressed because the fluorine ion and the chlorine ion are small ions and the response to voltage application is fast.
Moreover, it is more preferable that the copolymer contains a copolymer component (4) composed of the following structural formula (4).

（構造式（４）において、Ｒ_７は水素原子もしくはメチル基を示し、Ｒ_８はｎ−ブチル基、シクロヘキシル基、アダマンチル基、ジシクロペンタニル基、又はジシクロペンテニル基のいずれかを示す）

(In Structural Formula (4), R ₇ represents a hydrogen atom or a methyl group, and R ₈ represents an n-butyl group, a cyclohexyl group, an adamantyl group, a dicyclopentanyl group, or a dicyclopentenyl group)

In the structural formula (4), R ₈ is preferably any one of a cyclohexyl group, an adamantyl group, a dicyclopentanyl group, and a dicyclopentenyl group.
When the copolymer contains the copolymer component (4) composed of the structural formula (4), the polarity is lowered, so that the dispersibility in the silicone rubber is improved. As a result, image density unevenness can be reduced when used as a developing roller.

<Surface layer 13>
As shown in FIG. 1, the developing roller of the present invention has a surface layer 13 covering the surface of the elastic layer 12. Examples of the base layer resin for the surface layer include the following.
Polyamide resin, urethane resin, urea resin, imide resin, melamine resin, fluorine resin, phenol resin, alkyd resin, silicone resin, polyester resin, polyether resin, nylon resin, and a mixture of at least two resins selected from the above resins.

Of these, a urethane resin having a large ability to charge the developer (toner) by friction and having wear resistance is preferable. Of these, polyether polyurethane resins and polyester polyurethane resins are more preferred because of their low hardness and high flexibility.
As said polyether polyurethane resin, what is obtained by reaction of polyether polyol and an isocyanate compound can be mentioned. Examples of such polyether polyols include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. In addition, these polyol components may be prepolymers that are chain-extended with an isocyanate such as 2,4-tolylene diisocyanate (TDI), 1,4 diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI), if necessary.

  Moreover, as a polyester polyurethane resin, what is obtained by reaction of polyester polyol and an isocyanate compound can be mentioned. Examples of the polyester polyol include polyethylene adipate (PEA), polybutylene adipate (PBA), polyhexylene adipate, ethylene adipate, and a copolymer of butylene adipate.

  As isocyanate compounds to be reacted with these polyol components, aliphatic polyisocyanates such as ethylene diisocyanate, 1,6-hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), cyclohexane 1,3-diisocyanate, cyclohexane 1,4- Mention may be made of alicyclic polyisocyanates such as diisocyanates, aromatic polyisocyanates such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate (TDI) and diphenylmethane diisocyanate (MDI). These may be used as a modified product, a copolymer, or a block body thereof.

  The surface layer 13 preferably contains a conductivity imparting agent in order to impart conductivity. As the conductivity imparting agent, carbon black is preferable. The content of carbon black in the conductive resin layer is 0.5 to 50.0 parts by mass with respect to 100.0 parts by mass of the base resin forming the conductive resin layer. It is preferable because the property can be within a preferable range. The volume average particle diameter of the carbon black to be used is not particularly limited, but is preferably a volume average particle diameter of 15 to 50 nm from the viewpoint of film strength and conductivity.

  Further, fine particles may be added to the surface layer 13 in order to control the roughness of the roller surface. The fine particles for controlling roughness preferably have a volume average particle size of 8 to 30 μm. Moreover, it is preferable that the particle addition amount added to a resin layer is 1.0-50.0 mass parts with respect to 100.0 mass parts of resin solid content of a resin layer. The developing roller of the present invention is useful as a developing roller for a process cartridge in a process cartridge type image forming apparatus and as a developing roller for an electrophotographic apparatus such as a copying machine, a facsimile machine, or a printer.

An example of the process cartridge and the electrophotographic apparatus of the present invention is shown in FIG.
The process cartridge 22 of the present invention regulates at least the developing roller 1, the toner applying member 7 that supplies the toner 23 contained in the toner container 24 to the developing roller 1, and the toner conveyance amount on the developing roller 1. The toner amount regulating blade 9 is used. The process cartridge 22 is configured to be removable from the main body of the electrophotographic apparatus.

  The developing roller 1 is mounted in contact with the photosensitive drum 21 and the toner application member 7. An electrostatic latent image is formed by the laser beam 25 on the photosensitive drum 21 charged by the charging member 26, and the electrostatic latent image is visualized by toner carried and conveyed to the developing roller 1. Is done. The toner remaining on the photosensitive drum 21 is scraped off by the cleaning blade 28 and scraped off into the waste toner container 27.

  Here, the toner application member 7 is preferably an elastic roller member such as resin, rubber, or sponge. Among these, an elastic roller made of urethane foam is more preferable from the viewpoints of durability, hardness, and triboelectric chargeability to the toner. As the toner application member, a belt member or a brush member may be used instead of the elastic roller. The toner that has not been transferred to the photosensitive drum 21 is once peeled off from the surface of the developing roller 1 by the toner application member 7, thereby preventing the generation of stationary toner on the developing roller 1 and uniformizing the toner charge. To do.

  Next, as the toner used in the process cartridge of the present invention, either pulverized toner or polymerized toner can be used. Among these, a polymerized toner can be produced while controlling the particle diameter and shape of the toner during the production process, and thus is preferable for producing a toner having a uniform and small particle diameter.

The volume average particle diameter and the average circularity of the toner are not particularly limited, but it is easy to form a high-resolution and high-definition image, so that the volume average particle diameter is 4 to 8 μm and the average circularity (S) is high. More preferably, 0.960 ≦ S ≦ 1.000.
The volume average particle diameter of the toner can be measured by the following method.
An interface (manufactured by Nikka) and a PC 9801 personal computer (manufactured by NEC) are connected to Coulter Multisizer II (trade name, manufactured by Coulter, Inc.). As the electrolytic solution, a 1% NaCl aqueous solution may be prepared using primary sodium chloride, but ISOTON R-II (manufactured by Coulter Scientific Japan) may be used. 1 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 ml of the electrolytic solution, and 10 mg of a measurement sample is further added. The electrolytic solution in which the measurement sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes. The volume particle size distribution of 16 channels was measured in the range of 1.59 μm to 64.00 μm using a Coulter multisizer employing a 100 μm aperture with the sonicated electrolyte as the measurement sample, and the measured 50% D diameter Is the volume average particle size.

On the other hand, the average circularity (S) of the toner is measured using a flow type particle image measuring apparatus FPIA-2000 (manufactured by Toa Medical Electronics Co., Ltd.) as an index for simply and quantitatively expressing the sphericity of the toner. And the value obtained from the following equation can be adopted.
(formula)
Equivalent circle diameter = (particle projected area / π) ^1/2 × 2
Circularity = (perimeter of a circle having the same area as the particle projection area) / (perimeter of the particle projection image)
Here, the “particle projected area” is the area of the binarized toner particle image, and the “peripheral length of the particle projected image” is the length of the contour line obtained by connecting the edge points of the toner particle image. Define. In the present invention, the circularity is an index indicating the degree of unevenness of the toner particles, and is 1.000 when the toner particles are completely spherical. The more complicated the surface shape, the smaller the circularity.

  Next, the toner amount regulating blade 9 used in the process cartridge of the present invention will be described. As a member for regulating the toner layer thickness on the developing roller 1, a toner amount regulating blade 9 made of a rubber elastic material such as urethane rubber or silicone rubber or a metal elastic material such as phosphor bronze or stainless copper is used. is doing.

  A thinner toner layer can be formed on the developing roller 1 by pressing the toner amount regulating blade 9 against the developing roller 1 in a posture opposite to the rotation direction of the developing roller 1. The toner amount regulating blade 9 is preferably conductive for a particularly stable regulating force and a stable (negative) charge imparting property to the toner, and more preferably stainless steel.

  The contact pressure of the toner amount regulating blade 9 against the developing roller 1 is that the linear pressure is 5 g / cm or more and 50 g / cm or less, so that the regulation of the toner can be stabilized and the toner layer thickness can be suitably adjusted. Is preferable.

  The color electrophotographic apparatus shown in the schematic diagram of FIG. 2 has an image forming unit 10 (10a to 10d) provided for each color toner of yellow Y, magenta M, cyan C, and black BK in a tandem format. The specifications of the image forming unit 10 are the same in the basic configuration, although there are some differences depending on the characteristics of each color toner. The image forming unit 10 is detachable from the electrophotographic apparatus. On the other hand, in the color electronic image forming apparatus, not only the tandem format, but also a rotary format in which each color process cartridge is arranged around a photosensitive drum incorporated in the main body of the electrophotographic apparatus and develops necessary colors while rotating. It may be.

  The toner image on the photosensitive drum 21 is transferred onto the recording medium 36 by applying a bias power source 32 from the back surface of the recording medium 36 such as paper supplied by the pair of paper feed rollers 37 and conveyed by the conveying belt 34. A transfer member having a transfer roller 31 is provided. The conveying belt 34 is suspended from the driving roller 30, the driven roller 35, and the tension roller 33, and the image forming unit and the image forming unit are configured to sequentially superimpose and transfer the toner images formed in the respective image forming units on the recording medium 36. The recording medium 36 is controlled to move synchronously and to carry the recording medium 36. The recording medium 36 is electrostatically attracted to the transport belt 34 and transported by the action of the suction roller 38 provided immediately before reaching the transport belt 34.

  Further, in the color electrophotographic apparatus, a fixing device 29 for fixing the toner image superimposed and transferred onto the recording medium 36 by heating or the like, and a conveying device (not shown) for discharging the recording medium 36 on which the image has been formed out of the apparatus. )). The recording medium 36 is peeled off from the conveying belt 34 by the action of the peeling device 39 and sent to the fixing device 29.

  Hereinafter, the present invention will be described in more detail with reference to examples.

<Example of production of copolymer solution>
(Production example of copolymer solution A1)
The materials shown in Table 1 were mixed in a four-necked separable flask equipped with a stirrer, a cooler, a thermometer, and a nitrogen introduction tube, and stirred until the system became uniform.

撹拌を続けながら、反応系内の温度が７０℃になるまで昇温し、窒素導入還流状態で８時間反応させた。更に、この溶液をエタノールで希釈して固形分４０質量％の共重合体溶液Ａ１を得た。得られた共重合体の重量平均分子量は１３８００であった。

While continuing to stir, the temperature in the reaction system was raised to 70 ° C., and the reaction was carried out for 8 hours in a nitrogen-introduced reflux state. Further, this solution was diluted with ethanol to obtain a copolymer solution A1 having a solid content of 40% by mass. The weight average molecular weight of the obtained copolymer was 13,800.

(Production examples of copolymer solutions A1 to A12, B1, B2, C1 to C11, D1, and D2)
The copolymer solutions A2 to A12, B1 were the same as the A1 production example except that the types and the joints (parts by mass) of the copolymerization components (1) to (4) used were as shown in Table 2. , B2, C1 to C11, D1, and D2. Table 2 shows the weight average molecular weight (Mw) of the obtained copolymer.

In Table 2, the substances indicated by the abbreviations described in the column of copolymerization components are as follows.

M2VPF: 1-methyl-2-vinylpyridinium fluoride H2VPF: 1-n-hexyl-2-vinylpyridinium fluoride H2VPCl: 1-n-hexyl-2-vinylpyridinium chloride M4VPF: 1-methyl-4-vinylpyridinium fluoride Ride M4VPCl: 1-methyl-4-vinylpyridinium chloride H4VPF: 1-n-hexyl-4-vinylpyridinium fluoride H4VPCl: 1-n-hexyl-4-vinylpyridinium chloride H4VPBr: 1-n-hexyl-4-vinyl Pyridinium bromide H4VPPTSA: 1-n-hexyl-4-vinylpyridinium paratoluenesulfonic acid Td2VPCl: 1-n-tridecyl-2-vinylpyridinium chloride Td4VPCl: 1-n-to Ridecyl-4-vinylpyridinium chloride DMAEMA: dimethylaminoethyl methacrylate DEAEMA: diethylaminoethyl methacrylate DMAEA: dimethylaminoethyl acrylate BMA: n-butyl methacrylate CHMA: cyclohexyl methacrylate AdMA: adamantyl methacrylate DCPentaMA: dicyclopentanyl methacrylate DCPenteMA: dicyclopentenyl Methacrylate

[Example 1]
(Example of elastic layer adjustment)
The materials shown in Table 3 were blended to form a liquid silicone rubber base material.

A liquid A was prepared by blending the above base material with 0.5 parts by mass of a complex solution of chloroplatinic acid and divinyltetramethyldisiloxane (0.5% by mass) as a curing catalyst. Moreover, the B liquid which mix | blended 1.5 mass part of dimethylsiloxane-methylhydrogensiloxane copolymer (H content 0.30 mass% couple | bonded with Si atom) with the said base material at both terminal Si-H group. Prepared.
A cylindrical shaft core made of a SUM material (free-cutting steel material) having a diameter of 6 mm and a length of 364 mm, the surface of which was primed, was placed in the center of the cylindrical mold. A mixture of liquid A and liquid B mixed at a mass ratio of 1: 1 was poured into this mold, cured by heating at a temperature of 130 ° C. for 5 minutes, and further post-cured at a temperature of 200 ° C. for 2 hours to a length of 330 mm. An elastic roller having an elastic layer with a thickness of 3 mm was obtained.

(Example of surface layer adjustment)
As a material for the surface layer, MDI-based polyisocyanate (trade name: CORONATE 2521, manufactured by Nippon Polyurethane Industry Co., Ltd.), 124.9 parts by mass with respect to 100.0 parts by mass of polyether polyol (trade name: PTG2000, manufactured by Hodogaya Chemical Co., Ltd.) Then, 36.0 parts by mass of carbon black (trade name: MA230, manufactured by Mitsubishi Chemical Corporation) was mixed with stirring. Then, it was dissolved in methyl ethyl ketone so as to have a total solid content ratio of 30% by mass, mixed and then uniformly dispersed with a sand mill to obtain a coating material for forming a surface layer.

  Further, this surface layer forming coating material was diluted with methyl ethyl ketone so as to have a viscosity of 10 to 13 cps, and then coated on the elastic layer. The liquid circulation type dip coating apparatus shown in FIG. 3 was used for coating. The cylindrical immersion tank 40 in FIG. 3 has an inner diameter slightly larger than the outer diameter of the developer carrier, and has a depth larger than the axial length of the developer carrier. An annular liquid receiving portion 44 is provided on the outer periphery of the upper edge of the immersion tank 40 and is connected to the stirring tank 42. The bottom of the immersion tank 40 is connected to the stirring tank 40. The paint in the stirring tank 42 is sent to the bottom of the immersion tank 40 by the liquid feed pump 41. The paint overflows from the upper end of the immersion tank 40 and returns to the stirring tank 42 via the liquid receiving part 44 on the outer periphery of the upper edge of the immersion tank 40. The shaft core 11 provided with the elastic layer 12 is fixed vertically to the lifting device 43, immersed in the immersion tank 40, and then pulled up, the paint is applied on the elastic layer 12. After the applied coating material was dried, the surface layer 13 having a film thickness of about 20 μm was provided on the outer periphery of the elastic layer 12 by heat treatment at a temperature of 150 ° C. for 1 hour, whereby the developing roller 1 was obtained.

[Examples 2 to 12]
Developing rollers 2 to 12 were obtained in the same manner as in Example 1 except that the copolymer solution A1 in the adjustment example of the elastic layer was changed to A2 to A12.
[Examples 13 to 14]
Developing rollers 13 to 14 were obtained in the same manner as in Example 1 except that the copolymer solution A1 in the adjustment example of the elastic layer was changed to B1 and B2.
[Examples 15 to 25]
Developing rollers 15 to 25 were obtained in the same manner as in Example 1 except that the copolymer solution A1 in the elastic layer adjustment example was changed to C1 to C11.
[Examples 26 to 27]
Developing rollers 26 to 27 were obtained in the same manner as in Example 1 except that the copolymer solution A1 in the adjustment example of the elastic layer was changed to D1 to D2.

[Comparative Example 1]
Developing rollers 28 to 33 were obtained in the same manner as in Example 1 except that the copolymer solution A1 in the elastic layer preparation example was changed to a solution having the composition shown in Table 4 below.

[Comparative Examples 2 to 4]
In Comparative Example 1, except that the composition of the solution described in Table 4 was changed as shown in Table 5 below, ethanol 100.0 was used instead of the copolymer solution in the elastic layer preparation example as in Comparative Example 1. The developing rollers 29 to 31 were obtained in the same manner as in Example 1 except that the solution was changed to a part added with respect to parts by mass.

[Comparative Example 5]
Example except that the solution was changed to a solution in which 20.0 parts by mass of tetrabutylammonium fluoride was added to 100.0 parts by mass of ethanol instead of the copolymer solution A1 in the preparation example of the elastic layer. 1 to obtain a developing roller 32.
[Comparative Example 6]
Instead of the copolymer solution A1 in the preparation example of the elastic layer, the same as in Example 1 except that the conductive material was changed to 7.0 parts by mass of acetylene black (trade name: Denka Black; manufactured by Denki Kagaku Kogyo). The developing roller 33 was obtained by this method.

[Molecular weight measurement]
The apparatus and conditions used for measuring the weight average molecular weight (Mw) in this example are as follows.
Measuring instrument: HLC-8120GPC (manufactured by Tosoh Corporation)
Column: TSKgel SuperHM-M (manufactured by Tosoh Corporation) x 2 Solvent: THF (tetrahydrofuran, 20 mM triethylamine added)
Temperature: 40 ° C
THF flow rate: 0.6 ml / min
The measurement sample was a 0.1% by mass THF solution. Further, an RI (refractive index) detector was used as a detector for measurement.
As standard samples for preparing calibration curves, TSK standard polystyrene A-1000, A-2500, A-5000, F-1, F-2, F-4, F-10, F-20, F-40, F- A calibration curve was prepared using 80, F-128 (manufactured by Tosoh Corporation), and the weight average molecular weight was determined from the retention time of the measurement sample obtained based on this.

The following evaluation was performed on the developing rollers obtained in the above Examples and Comparative Examples. The evaluation results are shown in Table 4. The laser printer (trade name: Satera LASER BEAM PRINTER LBP9600C; manufactured by Canon Inc.) used for the evaluation is an A3 output machine, and the output speed of the recording medium is 30 sheets / min. Further, the contact pressure and the approach amount of the developing roller to the toner amount regulating blade were set such that the toner carrying amount on the developing roller was 0.40 mg / cm ² .

(1) Durability evaluation;
Each of the developing rollers according to each of Examples and Comparative Examples was incorporated as a developing roller in the magenta cartridge of the laser printer, and an electrophotographic image was output in an environment of a temperature of 25 ° C. and a humidity of 50% RH. Specifically, one solid black image was output after the cartridge was mounted, 5000 images with a printing rate of 1% were output, and then one solid black image was output. This operation was repeated until a total of 15000 sheets were output. The output solid black image was measured for density using a densitometer (trade name: 504 spectral densitometer; manufactured by X-Rite Co., Ltd.), and evaluated according to the following criteria.
A: The density difference between the 1st and 15000th solid black images is less than 0.2.
B: The density difference between the first and 10,000th solid black images is less than 0.2, and the density difference between the first and 15000th solid black images is 0.2 or more.
C: The density difference between the first and 5000th solid black images is less than 0.2, and the density difference between the first and 10000th solid black images is 0.2 or more.
D: The density difference between the first and 5000th solid black images is 0.2 or more.

(2) Blade bias leak evaluation;
Each developing roller according to each of the examples and comparative examples is incorporated into the black cartridge of the laser printer as a developing roller, and further modified so that a bias is applied to the developing blade mounted in the cartridge from the outside of the printer. did. The cartridge was loaded into the laser printer, and a halftone image was output while adjusting the voltage applied to the developing blade in an environment of a temperature of 30 ° C. and a humidity of 80% RH. The halftone image has a density measured by the above densitometer of 0.7. About the output halftone image, it observed visually and evaluated the blade bias leak on the following reference | standard.
A: The development blade bias with respect to the development bias is −500 V, and the occurrence of the horizontal stripe due to the blade bias leak is not confirmed.
B: A lateral streak caused by a blade bias leak is confirmed when the developing blade bias with respect to the developing bias is −300 V to −500 V.
C: Generation of lateral streaks due to blade bias leakage is confirmed when the developing blade bias with respect to the developing bias is −100 V to −300 V.
D: Generation of lateral streaks due to blade bias leak is confirmed until the developing blade bias with respect to the developing bias reaches -100V.

(3) Ghost;
Each of the developing rollers according to each of Examples and Comparative Examples was incorporated as a developing roller in the magenta cartridge of the laser printer, and an electrophotographic image was output in an environment of a temperature of 15 ° C. and a humidity of 10% RH. Specifically, solid black images (squares and circles) are arranged at equal intervals on a white background in an area corresponding to one rotation of the developing roller at the leading edge of the image, and the other portions are halftones. Was used. How the ghost of the hieroglyph image appears on the halftone of the output image was visually confirmed and evaluated according to the following criteria.
A: No difference in shading is observed.
B: A slight shade difference can be confirmed depending on the viewing angle.
C: A ghost is clearly confirmed visually.
D: Ghost appears over two or more development rollers.

(4) Image density unevenness;
The first solid black image output in the evaluation item (1) was visually observed and evaluated according to the following criteria.
A: Image density unevenness is not confirmed.
B: Slight density unevenness is confirmed depending on the viewing angle.
C: Although the density unevenness is slightly confirmed by a normal view, there is no practical problem.
D: Clear density unevenness is confirmed.

  Table 6 shows the evaluation results of Examples 1-27 and Comparative Examples 1-6.

As shown in the table, in the developing rollers 1 to 27 in Examples, a copolymer of the copolymer component (1) and / or (2) which is a quaternary pyridinium salt and a copolymer component (3) which is a tertiary amine. Therefore, a high effect on durability and blade bias leakage was obtained.
Further, in the developing rollers 1 to 8, 10, 12 to 22, 24, 26, and 27, the anionic species of the quaternary pyridinium salt is F ⁻ and / or Cl ⁻ , so that the current value of the developing roller is appropriate. And high effects were obtained in ghost evaluation.
In the developing rollers 15 to 27, since the functional group R _{8 of the} copolymer component (4) is any one of a cyclohexyl group, an adamantyl group, a dicyclopentanyl group, or a dicyclopentenyl group, Because of its high dispersibility, high effects on density unevenness were obtained.

On the other hand, in the developing rollers 28 to 31 in the comparative example, since the quaternary pyridinium salt and / or the tertiary amine does not form a copolymer, an effect on durability and / or blade bias leakage is obtained. There wasn't.
Further, in the developing roller 32, the effect of blade bias leak was not obtained due to the use of electronic conductive carbon black.
Furthermore, in the developing roller 33, a quaternary ammonium salt was used as an ionic conductive material, but no effect was obtained on durability.

DESCRIPTION OF SYMBOLS 1 Developing roller 7 Toner application member 9 Toner amount control blade 10 Image forming part 10a-10d Image forming part (for each color)
11 shaft core 12 elastic layer 13 surface layer 21 photosensitive drum 22 process cartridge 23 toner 24 toner container 25 laser beam 26 charging member 27 waste toner container 28 cleaning blade 29 fixing device 30 drive roller 31 transfer roller 32 bias power source 33 tension roller 34 Conveying belt 35 Followed roller 36 Recording medium 37 Paper feed roller pair 38 Adsorption roller 39 Peeling device 40 Immersion tank 41 Liquid feed pump 42 Stirring tank 43 Lifting device

Claims (6)

It has a shaft core, an elastic layer and a surface layer in this order,
The elastic layer is
Contains a silicone rubber and a copolymer having one or both structural units selected from the group consisting of the following structural formula (1) and the following structural formula (2), and a structural unit represented by the following structural formula (3) Developing roller characterized by:

(In Structural Formulas (1) to (3), R ₁ and R ₂ each independently represents an alkyl group having 1 to 13 carbon atoms, R ₃ represents a hydrogen atom or a methyl group, and R ₄ represents a carbon number. 2 to 4 alkylene groups, R ₅ and R ₆ each independently represents an alkyl group having 1 to 2 carbon atoms, X ₁ ^- and X ₂ ^- represent anionic species). The developing roller according to claim 1, wherein the anion species X ₁ ⁻ and X ₂ ⁻ are fluorine ions or chlorine ions. The developing roller according to claim 1 or 2, wherein the copolymer further has a structural unit represented by the structural formula (4).

(In Structural Formula (4), R ₇ represents a hydrogen atom or a methyl group, and R ₈ represents an n-butyl group, a cyclohexyl group, an adamantyl group, a dicyclopentanyl group, or a dicyclopentenyl group) . The developing roller according to claim 3, wherein, in the structural formula (4), R ₈ is any one of a cyclohexyl group, an adamantyl group, a dicyclopentanyl group, and a dicyclopentenyl group.   A process cartridge configured to be detachable from a main body of an electrophotographic apparatus, comprising the developing roller according to any one of claims 1 to 4.   An electrophotographic apparatus having a photosensitive drum and a developing roller disposed in contact with the photosensitive drum, wherein the developing roller is the developing roller according to any one of claims 1 to 4. An electrophotographic apparatus.

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