JP3493914B2 - Developing roller - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in a developing roller used in a developing device incorporated in an electrophotographic copying machine, a printer, a facsimile receiving device, or the like, with its surface being in contact with a photosensitive member. It relates to a developing roller.

[0002]

2. Description of the Related Art A developing roller is used in an electrophotographic copying machine, a printer, a receiving device of a facsimile, or the like to transfer toner to the surface of a photosensitive member.
Various types of developing rollers have been used or proposed, and among these, a contact type developing roller using a non-magnetic one-component toner, which is advantageous for colorization, is drawing attention. This developing roller is configured such that triboelectrically charged toner is adhered to the surface of the developing roller by an electric attraction force, and then the developing roller is pressed against the photoconductor to transfer the toner to the photoconductor.

A characteristic required of such a developing roller is that it is flexible because it requires a large nip width (a circumferential width of a contact area between the developing roller and the photosensitive member) in the developing section. Especially when the developing roller has a conductive rubber layer,
It is meaningless that only the conductive rubber layer is flexible, and the surface layer needs to be flexible. Being non-adhesive to the photoconductor in order not to interfere with the rotation of the photoconductor and the developing roller. Small dependence on environment such as humidity and temperature. All toners can be made to have the same polarity without being reversely charged. To this end, if the toner is negatively charged, the charge train on the surface layer of the developing roller must be on the positive side. This property is not essential, but it is preferable to be satisfied as much as possible. Excellent toner releasability in order to smoothly transfer the toner to the photoconductor and to smoothly remove the toner from the surface of the developing roller after development. That is, it is possible to prevent filming.

[0004]

It is preferable that the contact type developing roller satisfies all the characteristics listed in such a balance, but there is no conventional developing roller of this kind that satisfies all of them in good balance. . For example, as a developing roller of this type, one using a nylon-based, urethane-based, or fluorine-based resin as a surface layer is known, but each of them has the following problems.

(A) Nylon-based resins satisfy the requirements of "non-adhesiveness to the photoconductor" () and "not reverse charging the toner" (), but they are inferior in flexibility and therefore flexible rubber elasticity. It is difficult to satisfy the required flexibility as the outer surface layer of the body layer. For this reason, "having flexibility that allows a large nip width in the developing section."
The element () cannot be satisfied. Also,
"Small dependency on environment such as humidity and temperature"
It is hard to say that () and “excellent toner releasability” () are also good.

(B) Urethane-based resins include those that are relatively rigid and those that are flexible due to differences in the degree of polymerization, etc. However, rigid resins have the same problems as the above nylon-based resins, while those that are flexible Has surface tackiness, and therefore, there is a problem that the element "having no tackiness to the photoreceptor" () cannot be satisfied.

C) Fluorocarbon resin is good when the toner is positively charged, but "does not reversely charge the toner" when the current mainstream toner is negatively charged ().
Requirement is not met. In addition, in the case of a composition that sufficiently exhibits the characteristics of a fluorine-based system that satisfies both "small dependence on environment such as humidity and temperature" () and "excellent toner releasability" () It is very difficult to handle and expensive. The present invention intends to provide a developing roller having a well-balanced improvement in the above-mentioned problems relating to the surface layer of the developing roller and having the properties required as described above in a well-balanced manner.

[0008]

[Means for Solving the Problems] As a result of intensive studies to solve the above problems, in order to obtain a surface layer that satisfies all of the above, a flexible component is used as a matrix and a rigid component is used as a domain. It has been found that it is effective to form the surface layer of the developing roller with a resin having a sea-island structure. That is, "have flexibility."
() And "Do not reverse-charge the toner" () is filled with a matrix component made of a flexible resin, while "non-adhesive to the photoreceptor"
(), "Small dependency on environment such as humidity and temperature" () and "Excellent toner releasability"
The element () is filled with a domain component made of rigid resin. In this case, the sea-island structure uses a water-repellent domain component. As another aspect,
When the surface layer is formed of a resin having a sea-island structure that fills the elements of ,, and with the matrix component made of a flexible resin and the domain component made of a rigid resin, except the element "Do not reverse-charge the toner" (). There is also. In addition, various patterns are possible by combining the respective compositions of the domain and the matrix.

That is, the developing roller according to the first aspect is a developing roller of a type in which the surface of the developing roller is brought into contact with the photosensitive member and the toner is transferred to the photosensitive member, and the developing roller is provided around the metal shaft.
A conductive rubber layer having a JIS A hardness of 5 to 40 ° is provided.
Has a structure in which the outer peripheral surface is covered with a surface layer, and the surface layer has a sea-island structure containing two or more kinds of resin components, a flexible component as a matrix, and a rigid component as a domain ,
The elongation at yield of the domain component alone is 100% or less
The matrix component alone has an elongation at break of 250% or more
It is characterized by comprising a resin layer that is.

[0010]

Both the sea-island components can be urethane resins.

The conductive rubber layer has (A) at least one alkenyl group in the molecule,
A polymer (B) in which the repeating unit constituting the main chain is an oxyalkylene unit contains a curing agent (C) hydrosilylation catalyst having two or more hydrodosilyl groups in the molecule and (D) a conductivity-imparting agent. Can be used.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The developing roller 1 of the present invention has, for example, as shown in FIGS. 1 and 2, a JIS A hardness around a metal shaft 2 made of SUS or aluminum having a diameter (r) of about 1 to 12 mm. 5 to 40 °, preferably 10 to 3
A conductive rubber layer 3 having a thickness of about 1 to 15 mm at 0 ° is provided, and the outer peripheral surface thereof is covered with a surface layer 4. A mode in which a single layer or a plurality of layers are provided between the metal shaft 2 and the conductive rubber layer 3 and between the conductive rubber layer 3 and the surface layer 4 can be appropriately adopted as necessary.

The surface hardness of this roller is measured by a JIS A hardness tester and is 40 ° or less, preferably 30 ° or less when measured in the form of a roller, so that high quality image quality is maintained even at high speed printing. It is preferable from the viewpoint of being able to. Further, the conductivity of the roller 1, that is, the roller resistance is 10 ³ to 10 ⁸ Ω.
Is more preferable, and 10 ⁴ to 10 ⁷ Ω · cm is more preferable. The surface layer of the developing roller of the present invention is composed of two or more resin components, and the resin layer forming the surface layer has a sea-island structure. Here, having a sea-island structure means that the surface layer is formed on the roller as long as the surface layer has a sea-island structure, and the resin component itself before the surface layer formation is not necessarily the sea-island structure. It does not mean that it has a structure. Therefore, a case where a homogeneous resin material is used in the resin material stage, which contains components such as a compatibilizer, is also an object of the present invention.

The matrix resin having a sea-island structure of the present invention needs to be a resin softer than the domain resin. The flexibility of the matrix resin allows the base material to follow the deformation. For example, when the base is a flexible conductive rubber layer, the flexibility of the matrix resin corresponds to the deformation of the conductive rubber layer. Such a flexible matrix resin contributes to satisfying the above-mentioned characteristics required for the developing roller, but on the other hand, the matrix resin alone has the adhesive property of the matrix resin itself, and thus the above-mentioned photosensitive member failure. It is difficult to achieve tackiness. In the present invention, by interposing the domain resin in the matrix resin, the adhesiveness of the matrix resin is suppressed and the surface layer is made non-adhesive to the photoreceptor. In order to effectively exhibit such characteristics, the elongation at break of the matrix resin alone should be 2
00% or more, 100% of elongation at yield of domain resin alone
The following is desirable. Regarding the elongation, 23
It is a value at a temperature of 200 ° C. and a tensile speed of 200 mm / min. If there is something that causes plastic deformation, the domain resin adopts elongation at the yield point.

As a concrete mode of the sea-island structure, it is preferable that the domain size is about 1 μm to 10 μm.
If it is less than 1 μm, it becomes difficult to relax the surface tackiness of the flexible matrix component. On the other hand, if it exceeds 10 μm, the variation in physical properties of the roller (mainly electrical characteristics) tends to increase.

Examples of the domain resin include, but are not limited to, an epoxy resin, a urea resin, a urea resin, a melamine resin, a urethane resin having a small molecular weight between crosslinking points, and a styrene resin. As a matrix resin,
Examples thereof include urethane resins, silicone rubbers, EP rubbers, and fluorine rubbers having a large molecular weight between cross-linking points, but not limited thereto.

Further, in consideration of the fact that the toner is generally mainly negatively charged, it is desirable to adopt a sea-island structure of urethane resins having a positive charging line. For example, a case where a sea-island structure is formed by using a method of emulsifying and dispersing a hydrophobic urethane prepolymer to be dispersed with a hydrophilic urethane prepolymer dispersant and the like can be given as an example. In addition, these surface layer compositions are
It is applied with P, spray, roll quota, etc., and dried (partially cured) to form a surface layer.

It is desirable that the conductive rubber layer that is the base of the surface layer is flexible. If the conductive rubber layer is not flexible, as described above, even if the surface layer is made flexible, it is difficult to realize the flexibility of the developing roller as a whole, and it is meaningless.
Examples of the flexible conductive rubber layer include those described in claim 3 .

The conductive rubber layer according to claim 3 has (A) at least one alkenyl group in the molecule,
Polymer (B) whose repeating unit constituting the main chain is an oxyalkylene unit (C) Curing agent having two or more hydrodosilyl groups in the molecule (C) Hydrosilylation catalyst and (D) Curable electroconductivity Containing a sex composition. The contents of this curable conductive composition will be described below. Specific examples of the curable conductive composition include, for example, a polymer having at least one alkenyl group in the molecule and a repeating unit constituting the main chain being an oxyalkylene unit (A) component, molecule Component (B) which is a curing agent having two or more hydrosilyl groups therein, component (C) which is a hydrosilylation catalyst, and conductivity imparting agent (D)
An example of the layer is a curable conductive composition containing the above components (A), (B), (C), and (D). Of course, it goes without saying that a layer made of another composition, for example, a layer made of polyurethane, polysiloxane, NBR, EPDM or the like may be provided below the layer made of the curable conductive composition. Of course, the entire outer side of the shaft may be a layer formed of the curable conductive composition. In this case, a conductive rubber having characteristics such as low hardness, low compression set and bleedless can be obtained.

Details of this curable conductive composition will be described below. The component (A) in the curable conductive composition is a component that reacts with the component (B), which is a curing agent, and cures to become a cured product having rubber elasticity.

The repeating unit constituting the main chain of the component (A) is an oxyalkylene unit, and the main chain has a compound having two or more active hydrogens as a starting material, for example, ethylene glycol, bisphenol compound, glycerin, trimethylol. It is produced by polymerizing a C2-C4 alkylene oxide using propane, pentaerythritol, or the like. Specific examples of the polymer constituting the main chain thus produced include, for example, two or more random or block copolymers of polyethylene oxide, polypropylene oxide, polybutylene oxide, ethylene oxide, propylene oxide and butylene oxide. It is preferable that an alkenyl group is introduced at the terminal from the viewpoint of rubber elasticity.

A preferred specific example of a polymer having at least one alkenyl group in the molecule and having a repeating unit constituting the main chain as an oxyalkylene unit is, from the viewpoint of lowering the hardness of the cured product, The repeating unit of the chain is preferably an oxypropylene unit, and when water absorption is required, a copolymer in which a part of the oxypropylene unit is changed to an oxyethylene unit is preferable.

The number of alkenyl groups contained in the component (A) is required to be at least one in order to react with the component (B), but it is preferably 2 to 6.

The molecular weight of the component (A) is a number average molecular weight (Mn) from the viewpoint of the balance between reactivity and low hardness.
500 to 50,000, and even 1,000 to 20,000
It is preferable that the alkenyl group is present at the terminal of the molecule,
It is preferable from the viewpoint of low hardness.

Next, (B) in the conductive curable composition
The component, which is a curing agent having at least two hydrosilyl groups in the molecule, is a component (A) having at least one alkenyl group in the molecule, and the repeating unit constituting the main chain is an oxyalkylene unit. Is a component that acts as a curing agent for the polymer.

The component (B) contains at least 2 in the molecule.
Preferably 2 to 50, more preferably 2 to 30
More preferably 2 to 20 and even more preferably 3 to 12
Since it has one hydrosilyl group, each hydrosilyl group reacts with the alkenyl group present in the molecule of the component (A) to cure. When the number of hydrosilyl groups in the component (B) is less than 2, the curing speed in curing the curable conductive composition by a hydrosilylation reaction becomes slow, and curing failure often occurs. When the number of the hydrosilyl groups is more than 50, the stability of the curing agent as the component (B), and thus the stability of the curable conductive composition, deteriorates, and moreover, a large amount of hydrosilyl groups remains after curing. It tends to remain during curing, which can easily cause voids and cracks.

In the above case, having one hydrosilyl group means having one SiH, and in the case of SiH ₂ , having two hydrosilyl groups, the H bonded to Si is different from Si. It is better to bond to
It is also preferable from the viewpoint of rubber elasticity.

The molecular weight of the component (B) is preferably 30,000 or less, more preferably 20,000 or less, and particularly preferably 20,000 or less in terms of the dispersibility of the component (D), which will be described later, and roller processability. It is preferably 15,000 or less. 30 considering the reactivity and compatibility with the component (A)
0 to 10000 is preferable.

The component (B) as described above is not particularly limited, but for example, a polysiloxane curing agent can be preferably used. As a specific example, the following formulas (i) to (ii
Examples thereof include chain-like and cyclic polyorganohydrogensiloxanes such as i) (including polyoxyalkylene modified products, styrene modified products, olefin modified products, etc.).

[0031]

[Chemical 1] (M and n are integers, 10 ≦ m + n ≦ 50, 2 ≦ m, 0 ≦
n and R may be a methyl group, a polyoxyalkylene group having a molecular weight of 100 to 10,000, or a hydrocarbon group having 2 to 20 carbon atoms, and may contain one or more phenyl groups. When multiple R are included, they need not be the same. )

[0032]

[Chemical 2] (M and n are integers, 10 ≦ m + n ≦ 50, 2 ≦ m, 0 ≦
n and R may be a methyl group, a polyoxyalkylene group having a molecular weight of 100 to 10,000, or a hydrocarbon group having 2 to 20 carbon atoms, and may contain one or more phenyl groups. When multiple R are included, they need not be the same. )

[0033]

[Chemical 3] (M and n are integers, 3 ≦ m + n ≦ 20, 2 ≦ m ≦ 19, 0
≦ n ≦ 18, R is a methyl group, and the molecular weight is 100 to 1000
The polyoxyalkylene group having 0 or the hydrocarbon group having 2 to 20 carbon atoms may contain one or more phenyl groups. R
When a plurality of is included, these need not be the same. )

In order to improve the compatibility with the component (A), it is preferable that R contains a phenyl group. Further, from the viewpoint of easy availability, as R, —CH ₂ —CH ₂ —C ₆ H ₅ , —CH ₂ —CH (C
H ₃₎ -C ₆ H _5, but also from the viewpoint of storage stability, -C
_{H 2 -CH (CH 3) -C} 6 H 5 are preferred.

Other examples of the component (B) include, for example, the following general formula (1) R ¹ X _a (1) (wherein, X is a group containing at least one hydrosilyl group, and R ¹ is a carbon number. 2-150 monovalent to tetravalent hydrocarbon groups, a
Is an integer selected from 1 to 4, provided that when X contains only one hydrosilyl group, a is 2 or more. ), And a hydrocarbon-based curing agent containing a hydrosilyl group having an average molecular weight of 30,000 or less is a specific example.

In the general formula (1), X is at least one
It represents a group containing a dorosilyl group.
Is, for example, -SiH_n(CH₃)_3-n(However, n = 1
~ 3), -SiH_n(C₂H_Five)_3-n(However, n = 1 to 1
3), -SiH_n(C₆H_Five) _3-n(However, n = 1 to 1
3), -SiH₂(C₆H₁₃) Or other silicon atom
A hydrosilyl group containing only

[0037]

[Chemical 4]

A hydrosilyl group containing two or more silicon atoms such as

[0039]

[Chemical 5]

[0040]

[Chemical 6]

[0041]

[Chemical 7]

Examples thereof include hydrosilyl groups derived from various chain-like, skill-like, and cyclic polyvalent hydrogen siloxanes. In the formula, m units and p units, n units and q units, n units and p units and x units, n units and q units, It is described that y units, m units and n units, and further m units, n units, p units and q units are linked by block bonds. However, these may be block bonds or random bonds. The same applies to the following description.

Of the various hydrosilyl groups mentioned above,
Since the hydrosilyl group-containing hydrocarbon curing agent which is the component (C) is less likely to impair the compatibility with other organic polymers, the molecular weight of the part constituting the hydrosilyl group is 5
It is preferably 00 or less, and the following is preferable in consideration of the reactivity of the hydrosilyl group.

[0044]

[Chemical 8]

Hereinafter, these groups will be referred to as "groups represented by (Chemical Formula 8)".

In the general formula (1), R ¹ has 2 to 2 carbon atoms.
It represents 150 monovalent to tetravalent hydrocarbon groups and may be a group formed of a polymer. As a specific example,

[0047]

[Chemical 9]

[0048]

[Chemical 10]

Etc. (These are disclosed in Japanese Patent Laid-Open No. 3-95266.
It is described in the newsletter), R ¹Consists of a polymer
Specific examples of the group include ethylene, propylene and 1-butene.
Olefins with 2 to 6 carbon atoms such as amine and isobutylene
It is a polymerized compound of
Those with 1 to 4 hands, butadiene, isoprene, etc.
Diene compounds such as
For example, by copolymerizing a fin compound and a diene compound
It is hydrogenated and has 1 to 4 bonds.
And the like.

Among the hydrocarbon type curing agents represented by the general formula (1) having R ¹ and X as described above, R ¹ is a hydrocarbon group having 5 to 20 carbon atoms and X is the above-mentioned (formula 8). The combination in the case of the groups shown increases the reactivity,
It is preferable in terms of compatibility with the component (B).

Of these, R ¹ has 5 to 12 carbon atoms.
The hydrocarbon group is preferably a hydrocarbon group from the viewpoint of easy availability of raw materials, and X is a cyclic polysiloxane compound among the groups represented by the above (Chemical formula 8), and compatibility with the component (B) is It is preferable because it improves the quality. The compound obtained by this combination is preferable as the hydrocarbon-based curing agent. As a specific example, for example,

[0052]

[Chemical 11]

And the like.

In the curable conductive composition, the hydrosilylation catalyst as the component (C) is used together with the components (A) and (B). The hydrosilylation catalyst which is the component (C) is not particularly limited, and specific examples thereof include solid platinum supported on a carrier such as platinum, alumina, silica, carbon black, chloroplatinic acid, platinum chloride. Complexes of acids with alcohols, aldehydes, ketones, etc., platinum / olefin complexes, platinum / phosphite complexes and the like are preferable.

Further, the curable conductive composition contains (D)
A component that imparts conductivity is included. Examples of the conductivity imparting substance that is the component (D) include carbon black and
Fine metal powder, further organic compound or polymer having quaternary ammonium salt group, carboxylic acid group, sulfonic acid group, sulfuric acid ester group, phosphoric acid ester group, etc., ether ester amide, or ether imide polymer, ethylene oxide- Examples thereof include compounds having a conductive unit typified by epihalohydrin copolymers, methoxypolyethylene glycol acrylate and the like, and compounds imparting conductivity such as antistatic agents such as polymer compounds. A plurality of conductivity-imparting agents as the component (D) may be used.

The curable conductive composition is prepared from the components (A) to (D) described above. When forming such a curable conductive composition or conductive elastic layer 2, the JIS A hardness is 40 ° or less, preferably 25 ° or less, from the viewpoint of forming a good nip width with the regulating blade and the photoreceptor. The ratio of the components (A) and (B) used is (A)
The hydrosilyl group of the component (B) is 0.2 to 2.5 mol, and further 0.4 to 2. per mol of the alkenyl group in the component.
It is preferable to use it so that it is 5 mol. The amount of the hydrosilylation catalyst which is the component (C) is used in the range of 10 ^-1 to 10 ^-6 mol with respect to 1 mol of the alkenyl group in the component (A). Furthermore, the amount of the conductivity-imparting agent used as the component (D) is 0.1 to 50 parts, and further 0, relative to 100 parts (parts by weight, the same applies hereinafter) of the total amount of the components (A) to (C). ．
The volume resistance of the conductive elastic layer is 10 ³ to 10 at ³ to 30 parts.
It is used so as to have a resistance of about ¹⁰ Ω · cm, preferably 10 ⁵ to 10 ⁸ Ω · cm. If necessary, silica, non-conductive filler such as magnesium carbonate, anti-aging agent, etc. may be added to the curable conductive composition. The amount to be added is usually about 50 parts or less, preferably about 20 parts or less, based on 100 parts of the total amount of the components (A) to (D), which is preferable from the viewpoint of not increasing the rubber hardness. Next, examples of the present invention will be described.

[0057]

[Example] Around a SUS shaft having a diameter of 10 mm,
A conductive rubber layer having a thickness of 7.5 mm was provided, and the outer peripheral surface was covered with a surface layer to form a developing roller. As listed below, two types of conductive rubber layers and six types of surface layers were used, and a plurality of types of developing rollers were produced by combining these.

(Conductive rubber layer 1) Number average molecular weight (Mn)
8000, allyl-terminated polyoxypropylene-based polymer having molecular weight distribution 2: 100 parts by weight of polysiloxane-based curing agent (SiH-ized 0.36 mol / 10
0 g): 6.6 parts by weight, 10% isopropyl alcohol solution of chloroplatinic acid: 0.06 parts by weight: carbon black 3030B (manufactured by Mitsubishi Chemical): 7 parts by weight, and decompressed (10 mmHg or less, 120 minutes). I foamed. The obtained composition was coated around a SUS shaft having a diameter of 10 mm, and allowed to stand for 30 minutes in an environment of 120 ° C. in a mold for curing to prepare a rubber elastic body having a thickness of 7.5 mm. (Conductive rubber layer 2) Chemigum N68 manufactured by Goodyear
3B (bound acrylonitrile amount 33%, Mooney viscosity 2
A roller having the same size as the conductive rubber layer 1 was produced by an injection method using a composition in which 5 parts by weight of Ketjen Black EC was mixed with 100 parts by weight of NBR rubber of No. 8). (Surface layer 1) Terminal alkoxysilylated polypropylene oxide (Mn = 8000), with respect to 100 parts by weight, Epicoat 828 (made by Yuka Shell): 50 parts by weight, A-1122 (Nippon Unicar's aminosilane): 1 part by weight , Organic tin-based hydrolysis condensation catalyst: 2 parts by weight TAP (Epoxy curing agent manufactured by Kayaku Akzo): 5 parts by weight 3030B (carbon black manufactured by Mitsubishi Chemical): 8 parts by weight (3030B is a 3-roll end-alkoxysilylated polypropylene) The mixture was kneaded with oxide) The coating method was a roll quota, and the coating was dried in an environment of 50 ° C. for 5 hours to be cured. (Epicote 828 /
The elongation at yield of the TAP system was about 60%, and the elongation at break of the terminal alkoxylated polypropylene oxide / 3030B / tin catalyst was about 400%. ) Incidentally, the domain size of the epoxy resin in the SEM photograph is 1
It was about μm. (Surface layer 2) Ethylene oxide-propylene oxide random copolymer polyether polyol containing 80% of ethylene oxide units having a number average molecular weight of 4480 and dicyclohexylmethane-4,4'-diisocyanate at a ratio of 10: 1 with nitrogen gas flow. Urethane prepolymer 1 (NCO content 1.6%) was obtained by reacting for 3 hours in an environment of 110 ° C. Polyester polyol consisting of 1,3-butanediol, 1,4-butanediol and adipic acid having a number average molecular weight of 1500 and 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate at a ratio of 20: 5 at 105 ° C. Urethane prepolymer 2 (with an NCO content of 3.
2%) was obtained. Prepolymer 2: 20 parts by weight of prepolymer 1 was added to 100 parts by weight, and 180 parts by weight of water at 10 ° C. or lower was added dropwise with vigorous stirring. Then, while stirring with a homomixer, 3-aminomethyl-3,5,
16.2 g of a 40% aqueous solution of 5-trimethylcyclohexylamine was added, and a chain extension reaction was carried out for about 1 hour. Concentration 4
A 0.8% dispersion with a viscosity of 250 centipoise was obtained. The coating method was DIP, and the coating was dried and cured in an environment of 80 ° C. for 1 hour. Urethane prepolymer 1 / 3-aminomethyl-3-5-
5-trimethylcyclohexylamine elongation at break approx. 2
60% urethane prepolymer 2 / 3-aminomethyl-3-5-
90% elongation of 5-trimethylcyclohexylamine (surface layer 3) CM-8000 (copolymerized nylon manufactured by Toray)
The coating method for obtaining a solution in which 10 parts by weight of Elecut S512 (surfactant manufactured by Takemoto Oil & Fats) was added to 10% methanol of CM-8000: 100 parts by weight is DIP,
It was dried in an environment of 80 ° C. for 1 hour. (Surface layer 4) Samprene 1B802 (Urethane made by Sanyo Chemical Co., Ltd.) was diluted 3 times with MEK to obtain a solution. The coating method was DIP, and the coating was dried and cured in an environment of 80 ° C. for 1 hour. (Surface layer 5) Heimlen-Y237 (polyether urethane 2-component system manufactured by Dainichiseika) was diluted 4-fold with cyclohexanone. It was slightly cloudy. Application is DIP method 8
It was dried and cured in an environment of 0 ° C. for 1 hour. In addition, SE
In the M photograph, it had a sea-island structure having a domain of 3 to 7 μm. (Surface Layer 6) Heimlen-Y237 was diluted with a mixed solvent of cyclohexanone / DMF = 1: 1. It was transparent. The coating was carried out by a DIP method in an environment of 80 ° C. for 1 hour to dry and cure. In addition, in the SEM photograph, a domain of 1 μm or more was not confirmed.

By combining these conductive rubber layers and surface layers, the developing rollers of Examples 1, 2 and 3 and Comparative Examples 1, 2 and 3 were produced and evaluated. The evaluation was performed by "image quality" and "development" at the time when each of the developing rollers prepared above was attached to the developing roller attachment position of a commercially available 6-sheet printer (printer capable of producing 6 sheets per minute) and continuously operated for 5 hours. The toner filming condition on the roller surface "and" hand wrinkle "were evaluated. Filming means that toner that does not participate in development adheres to the surface of the developing roller, that is, toner adheres to a portion other than the area where the electrostatic latent image is formed. ) Is one of the causes of change. The presence or absence of hand wrinkles means the ability to follow the deformation of the underlayer of the surface layer. The evaluation details are as follows.

(Image quality): It was evaluated by solid black evaluation. ◎ is good, ○ is white with a magnifying glass, but visually good, △ is slightly white with visual inspection (Filming evaluation): ◎ is good, ○ △ is a little toner when viewed in detail Adhesion and Δ indicate that a small amount of toner is adhering. (Hand-wrinkle) It was examined whether or not wrinkles were generated on the roller surface when the roller surface was pressed by hand. The evaluation results are shown in Table 1.

[0061]

[Table 1]

As can be seen from Table 1, the developing rollers of Examples 1, 2, and 3, which are Examples of the present invention, are comparative Examples 1, 2, and 3.
The image quality and filming were better than those of the developing roller of No. 3.

[0063]

The developing roller of the present invention has a resin layer having a sea-island structure in which a flexible component is a matrix and a rigid component is a domain, and is a surface layer. Characteristics, that is, flexible, non-adhesive to the photoreceptor, less dependent on the environment such as humidity and temperature, and does not reverse charge the toner,
It is possible to obtain a developing roller having excellent toner releasability and well-balanced adjustment of each of these characteristics. The image is beautiful, there is no filming, and a flexible underlayer such as a conductive rubber layer is used. However, it is possible to obtain a developing roller that can follow the deformation of the base.

[Brief description of drawings]

FIG. 1 is a front view showing an example of a developing roller of the present invention.

FIG. 2 is a sectional view of the developing roller.

[Explanation of symbols]

1 developing roller 2 shaft 3 Conductive rubber layer 4 Surface layer

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-72889 (JP, A) JP-A-7-333915 (JP, A) JP-A-8-39699 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) G03G 15/08 501 F16C 13/00

Claims (3)

(57) [Claims] 1. A developing roller of the type in which the surface of a photoconductor is brought into contact with the surface of the photoconductor to transfer toner to the photoconductor.
Around the shaft, with a JIS A hardness of 5-40 °
A rubber layer is provided and the outer peripheral surface is covered with a surface layer.
The surface layer has a sea-island structure containing two or more resin components, a flexible component as a matrix, and a rigid component as a domain, and the domain component alone has an elongation at yield of 10 or less.
Or less 0%, a developing roller matrix component alone destruction toxin beauty is formed of a resin layer is 250% or more. 2. The developing roller according to claim 1 , wherein the sea-island component is a urethane resin . 3. The conductive rubber layer has (A) at least one alkenyl group in the molecule,
The repeating units that make up the main chain are oxyalkylene units.
Curing having two or more hydrodosilyl groups in a polymer (B) molecule
The layer containing the agent (C) hydrosilylation catalyst and (D) conductivity-imparting agent.
The developing roller described.