JP3493902B2 - Developing roller - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing roller used in contact with a photoconductor incorporated in an electrophotographic apparatus such as a copying machine, a printer or a facsimile receiver, and more particularly to a polyamide. The present invention relates to a developing roller having a surface protective layer in which fine particles made of a substance containing a fluorine atom are added to a resin or a polyurethane resin, and used in an elastic roller contact type developing method using a one-component non-magnetic developer.

[0002]

2. Description of the Related Art Generally, a functional roller including a developing roller has a conductive rubber elastic layer formed around a metal shaft and a surface layer formed on the surface thereof. When the surface layer of the developing roller contains a polyamide-based resin or a polyurethane-based resin as a main component, the chargeability of the toner will be good, and therefore, it is disclosed in Japanese Patent Publication No. 50-13661, and many applications have been filed thereafter. ing. In many cases, these resins have a solubility parameter of 12 or more, and even when variously modified, they are 10 or more. On the other hand, the conductive rubber elastic layer is made of silicone, EPD or the like because of its low hardness.
M and polyurethane are often used. Silicone, EP
In the case of DM, the solubility parameter is less than 8.4.
Further, in the case of polyurethane as well, when it is desired to have a non-plastic low hardness, the solubility parameter tends to be small, for example, by using a main chain skeleton having a small cohesive force in a long chain. On the other hand, as a prior art of adding fine particles (fine particles made of a substance containing a fluorine atom) to the surface layer of a developing roller, as disclosed in JP-A-3-263069, a non-fluorine-containing resin powder is used. This is a technique that focuses on tackiness and is used as a countermeasure for toner filming.

[0003]

On the surface layer of the developing roller, -NH such as polyamide resin or polyurethane resin is used.
When a CO-bond-containing resin is used and silicone, EPDM, or low-hardness polyurethane is used for the conductive rubber elastic layer, the difference in cohesive force between the two layers (for example, the difference in solubility parameter) becomes large and the adhesiveness is improved. Often cause problems,
The durability is often short.

[0004]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have proposed that the surface layer is a resin layer having a relatively large cohesive force, and the inner conductive rubber elastic layer has a relatively cohesive force. In the case of a small resin layer, by adding fine particles made of a substance containing a fluorine atom to the surface layer, it is effective not only to improve the adhesiveness of the surface layer but also to improve the adhesion to the inner conductive rubber elastic layer. Therefore, the present invention was completed, and the present invention was completed.

That is, the present invention is a developing roller used in contact with a photoconductor of an electrophotographic copying machine, printer, or the like, and having a solubility parameter of less than 8.4 around a metal shaft. A conductive rubber elastic layer made of a curable composition containing a resin as a main component is formed, and the conductive rubber elastic layer is made of a substance containing a resin having a —NHCO— bond as a main component and a fluorine atom. Covered with a surface protective layer consisting of a resin composition containing fine particles
The developing roller (claim 1), wherein the conductive rubber elastic layer has at least one alkenyl group in the molecule (A), and the repeating unit constituting the outgoing chain is an oxyalkylene unit. And (B) a curing agent having at least two hydrosilyl groups in the molecule, (C) a hydrosilylation catalyst, and (D) a conductivity-imparting agent as a main component. (Claim 2), the surface protection
The protective layer is formed by spraying the conductive rubber elastic layer
The development roller is applied to the surface (claim 3) .

[0006]

Roller resistance of the developing roller of the embodiment of the present invention is 10 ⁴ to 10 ⁸ ohms at DC100V applied, and preferably from about 10 ⁵ to 10 ⁸ ohms.

Further, the solubility parameter of the curable composition constituting the conductive rubber elastic layer of the developing roller according to the present invention being less than 8.4 means that n-
Pentane (7.0), diisobutyl ketone (7.8),
Cyclohexane (8.2), methyl isobutyl ketone (8.4), ethyl acetate (9.1), acetone (10.
Measurement was carried out with a dilute solution of 6 kinds of solvent of 0), and the solution in which the resin was most soluble was n-pentane, diisobutyl ketone,
Refers to a resin that is either cyclohexane.

The curable composition constituting the conductive rubber elastic layer in the developing roller of the present invention will be described. As the curable composition, silicone, a part of polyurethane (such as one having a low content of urethane bonds in the cured product),
A curable composition containing a saturated hydrocarbon as a main component and the like can be mentioned. Among them, in particular, (A) a polymer having at least one alkenyl group in the molecule and the repeating unit constituting the main chain being an oxyalkylene unit, and (B) 2 in the molecule.
A curable composition containing a curing agent having one or more hydrosilyl groups, (C) a hydrosilylation catalyst, and (D) a conductivity-imparting agent as main components is preferable.

In the curable composition, the component (A) 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, such as ethylene glycol, propylene glycol, a bisphenol compound and glycerin. , Trimethylolpropane, pentaerythritol and the like are used to polymerize C _{2 to} C ₄ alkylene oxides. Specific examples of the polymer constituting the main chain thus produced include, for example, polyethylene oxide, polypropylene oxide, polybutylene oxide, and two kinds selected from ethylene oxide, propylene oxide, and butylene oxide. The above-mentioned random or block copolymers can be mentioned, and it is preferable that an alkenyl group is introduced at the terminal from the viewpoint of rubber elasticity.

Specific examples of the polymer (component (A)) having at least one alkenyl group in the molecule and having a repeating unit constituting the main chain being an oxyalkylene unit include a cured product having a low hardness. From the viewpoint, the main chain repeating unit 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 from the viewpoint of reacting with the component (B), but 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.
500-50,000, and even 1,000-20,
000 is preferable, and one having an alkenyl group at the molecular end is preferable from the viewpoint of low hardness.

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

Since the component (B) has at least two hydrosilyl groups in the molecule, each hydrosilyl group reacts with the alkenyl group present in the molecule of the component (A) to cure. The number of hydrosilyl groups is preferably 2
-50, more preferably 2-30, and even 2-2
0 is preferable, and 3 to 12 is particularly preferable. When the number of hydrosilyl groups is less than two, the curing rate when the curable composition is cured by a hydrosilylation reaction becomes slow,
In many cases, poor curing will occur. When the number of hydrosilyl groups is more than 50, the stability of the curing agent as the component (B), and thus the stability of the curable composition, deteriorates, and a large amount of hydrosilyl groups remains in the cured product after curing. Tend to remain, and cause voids and cracks.

Here, having one hydrosilyl group usually means having one SiH, but the same Si
In the case where a plurality of Hs are bonded to each other, for example, SiH ₂ is said to have two hydrosilyl groups. This S
A plurality of Hs bonded to i may be bonded to different Si or the same Si, but different S
It is preferable that it is bonded to i from the viewpoint of better curability and rubber elasticity.

The molecular weight of the component (B) is preferably 30,000 or less, more preferably 20,000 or less, and particularly 15,000 or less in terms of number average molecular weight (Mn) in view of roller processability. preferable. Considering the reactivity and compatibility with the component (A), it is more preferably 300 to 15,000.

The structure of the component (B) as described above is not particularly limited. For example, the general formula (1): R ¹ X _a (1) (wherein, X is a group containing at least one hydrosilyl group). , R ¹ is a monovalent to tetravalent hydrocarbon group having 2 to 150 carbon atoms,
a is an integer selected from 1 to 4, provided that when X contains only 1 hydrosilyl group, a is 2 or more) and has a number average molecular weight of 30,000 or less. Specific examples of the contained hydrocarbon-based curing agent are given.

In the general formula (1), X represents a group containing at least one hydroxyl group, and specific examples thereof include --SiH _n (CH ₃ ) _3-n (where n =
_{1~3), - SiH n (C} 2 H 5) 3-n ( provided that, n =
_{1~3), - SiH n (C} 6 H 5) 3-n ( provided that, n =
1 to 3), —SiH ₂ (C ₆ H ₁₃ ), a hydroxyl group containing only one silicon atom,

[0020]

[Chemical 1]

A hydroxyl group containing two or more silicon atoms, such as

[0022]

[Chemical 2]

[0023]

[Chemical 3]

[0024]

[Chemical 4]

Examples thereof include hydrosilyl groups derived from various chain-like, branched-like, and cyclic polyvalent hydrogen siloxanes. In the formula, m units and p units, n units and q units, m 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 as the component (B) is less likely to impair the compatibility with other organic polymers, the molecular weight of the portion constituting the hydrosilyl group is 5
It is preferably 00 or less, and more preferably the following in consideration of the reactivity of the hydrosilyl group.

[0027]

[Chemical 5]

Hereinafter, these groups will be referred to as "groups represented by (Chemical Formula 5)".

In the general formula (1), R ¹ represents a monovalent to tetravalent hydrocarbon group having 2 to 150 carbon atoms, which may be a polymer group. As a specific example,

[0030]

[Chemical 6]

[0031]

[Chemical 7]

(Note that these are disclosed in Japanese Laid-Open Patent Application No. 3-9526.
No. 6, etc.), and specific examples of the group in which R ¹ is a polymer include ethylene, propylene,
Polymerized with an olefin compound having 2 to 6 carbon atoms such as 1-butene and isobutylene as a main monomer, and having 1 to 4 bonds, and a diene compound such as butadiene and isoprene alone. Polymerize,
The olefin compound and the diene compound are copolymerized and then hydrogenated, and examples thereof include one having 1 to 4 bond (s).

Among the hydrocarbon type hardeners 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 (formula 5). The combination in the case of the groups shown is preferable from the viewpoint of increasing the reactivity and forming a good network structure, and the compatibility with the component (A). Among these, it is preferable that R ¹ is a hydrocarbon group having 5 to 12 carbon atoms from the viewpoint that the raw material can be easily obtained, and X is a cyclic polysiloxane compound among the groups represented by the above (formula 5). It is preferable that the component (A) is more compatible with the component (A). The compound obtained by this combination is preferable as the hydrocarbon-based curing agent. As a specific example, for example,

[0034]

[Chemical 8]

And the like.

The method for producing the hydrosilyl group-containing hydrocarbon-based curing agent which is the component (B) is not particularly limited and may be produced by any method.

For example, (1) a SiCl group may be included in the molecule.
Hydrocarbon curing agent, LiAlH _Four, NaBH_FourSuch
To reduce the SiCl group in the curing agent to a SiH group.
(2) Functional group X in the molecule¹Have
Hydrocarbon compounds and the functional group X in the molecule¹React with
Functional group Y¹And compounds having both hydrosilyl groups
And (3) alkenyl group-containing charcoal
At least 2 hydrosilyl groups for hydrogenated compounds
Hydrosilylation of Polyhydrosilane Compounds Bearing a Group
By this, the hydrosilyl group can be converted to the hydrocarbon even after the reaction.
The method of leaving the compound in the molecule of the compound is exemplified.
It

Of the above methods, the method (3) can be preferably used because the manufacturing process is generally simple. In this case, two or more of the hydrosilyl groups of some polyhydrosilane compounds may react with the alkenyl groups of the hydrocarbon-based compound to increase the molecular weight, but those containing such increased molecular weight ( There is no problem even if it is used as the component B).

Further, a polysiloxane type curing agent can be used as the component (B). Specific examples thereof include chain-like and cyclic polyorganohydrogen siloxanes (including polyoxyalkylene modified products, styrene modified products, and olefin modified products) as described below.

[0040]

[Chemical 9]

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

[0042]

[Chemical 10]

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

[0044]

[Chemical 11]

(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 10
The polyoxyalkylene group of 0 to 10,000 or the hydrocarbon group of 2 to 20 carbon atoms may contain one or more phenyl groups. When multiple R are included, they need not be the same. )

In order to improve the compatibility with the component (A), it is preferable that R contains a phenyl group. Furthermore, from the ease of availability, -CH ₂ -CH
_{2 -C 6 H 5, -CH 2} -CH (CH 3) -C 6 H
₅ is also a single CH ₂ --CH (C
H ₃₎ -C ₆ H ₅ are preferred.

In the curable composition constituting the conductive rubber layer, the hydrosilylation catalyst as the component (C) is used together with the components (A) and (B).

The hydrosilylation catalyst as 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, Examples include complexes of chloroplatinic acid with alcohols, aldehydes, ketones, platinum / olefin complexes, platinum / phosphite complexes, and the like.

The curable composition is prepared from the components (A) to (C). The ratio of the component (A) and the component (B) used is (B) per 1 mol of the alkenyl group in the component (A).
From the viewpoint of rubber elasticity, it is preferable to use the hydrosilyl group in the component in an amount of 0.2 to 5.0 mol, more preferably 0.4 to 2.5 mol. The amount of the hydrosilylation catalyst which is the component (C) is the same as that of the alkenyl group 1 in the component (A).
It is used in the range of 10 ^-1 to 10 ^-6 mol per mol.

The curable composition further contains a conductivity-imparting agent as the component (D). Specific examples of the conductivity-imparting agent which is the component (D) include carbon black and metal powder, and further quaternary ammonium salt group, carboxylic acid group, sulfonic acid group, sulfuric acid ester group, phosphoric acid ester group and the like. Containing organic compound or polymer, ether ester amide or ether amide imide polymer, ethylene oxide-epihalohydrin copolymer,
Examples thereof include organic antistatic agents such as compounds having a conductive unit typified by methoxy polyethylene glycol acrylate polymers or polymer compounds, and a plurality of them may be used. The content of the component (D) is 100 parts by weight of the total amount of the components (A) to (C) from the viewpoint of reducing variation in resistance.
When the component (D) is solid, the content is preferably 20 parts by weight or less from the viewpoint of low hardness. It is preferably 0.5 to 10 parts by weight.

If necessary, a non-conductive filler such as silica and magnesium carbonate, an antioxidant and the like may be added to the above curable composition. The amount to be added is usually 5 with respect to 100 parts by weight of the total amount of the components (A) to (D).
It is preferably about 0 parts by weight or less, preferably about 20 parts by weight or less, from the viewpoint of not impairing good rubber elasticity.

Next, the surface protective layer will be described. Examples of the resin composition forming the surface protective layer include -NHCO
-There is no particular limitation as long as it is a resin having a bond. Further, some of the hydrogen atoms bonded to N may be modified. On the other hand, the fine particles made of a substance containing a fluorine atom to be added to the resin composition are not particularly limited as to the fine particles made of a substance containing a fluorine atom. For example, a fluorinated graphite or a fluororesin such as PTFE may be used. The following fine particles are included. In addition, it is also possible to control the surface roughness by utilizing the fact that the dispersion state varies depending on the content of fluorine atoms in the added fine particles and the cohesive force and solvent species of the resin composition that constitutes the surface protective layer. It is possible.

[0053]

【Example】

(Examples 1 to 3 and Comparative Examples 1 and 2) A conductive rubber elastic layer (I) or (II) as described below was formed around a metal (SUS) shaft having a diameter of 10 mm and a roller having a diameter of about 25 mm was used. Obtained. The surface of the protective layer (I) ~ (III) as follows
To obtain a developing roller (however, the thickness of the protective layer was all about 10 to 15 μm). The obtained roller was attached to the developing roller position of a printer (LP-1000; 4-sheet machine manufactured by Seiko Epson Corporation), and a roller durability test was performed by idling. The results are shown in Table 1.

Conductive rubber elastic layer (I): (A-i) number average molecular weight (Mn) 8,000, molecular weight distribution (Mw / Mn) 2.0 (measured by GPC), viscosity 130
100 g of P (poise; 20 ° C.) polyoxypropylene polymer (polyoxypropylene in which 90% of OH at both ends is allyl etherified), (B-I) formula

[0055]

[Chemical 12]

The polysiloxane curing agent (Si
H value of 0.358 mol / 100 g) 6.9 g, 10% iripropyl alcohol solution of chloroplatinic acid (H ₂ PtCl ₆ ) 0.06 g, and Ketjenblack EC
0.5 g was mixed and degassed under reduced pressure (10 mmHg, 120 minutes). The obtained composition was coated around a stainless steel shaft having a diameter of 10 mm, and the temperature was kept at 120 ° C. for 3 hours in a mold.
After curing for 0 minutes, a conductive rubber elastic layer having a thickness of 7.5 mm was provided around the stainless shaft. The solubility parameter of the composition was around 8.2.

Conductive Rubber Layer (II): The Conductive Rubber Layer (I)
Instead of the allyl-terminated polyoxypropylene-based polymer, the vinyl-terminated polyisobutylene polymer (Mn = 60
00) was used (most dissolved in diisobutyl ketone), and the procedure was the same as that of the conductive rubber elastic layer (I) except that the amount of the curing agent was 8 g. In this case, the solubility parameter of the composition was around 7.8.

Surface layer (I): CM-8000 (copolymerized nylon produced by Toray) in a 10% methanol solution was used to prepare CM-8000.
15 parts by weight of Cefbon CMA (fluorinated graphite made by Central Glass) was added to 100 parts by weight of solid content of 8000, and a solution was used which was dispersed by a sand grinder at 1000 rpm for 1 hour.

Surface layer (II): 13% of CM-8000
A solution prepared by mixing a Lubron LD-1E (manufactured by Daikin Industries, Ltd., PTFE dispersion) in a methanol solution at a weight ratio of 3: 1 was used.

Surface layer (III): 10 of CM-8000 above
% Methanol solution was used.

The surface protective layers (I) to (III) were applied on the surface of the conductive rubber elastic layer by a spray method so that the thickness was about 10 to 15 μm.

[0062]

[Table 1]

[0063]

As is apparent from Table 1, the addition of fine particles made of a substance containing a fluorine atom as the surface protective layer improves the adhesiveness with the conductive rubber elastic body layer as the inner layer and improves the durability of the roller. I got better. Further, the addition of fine particles made of a substance containing a fluorine atom also improves the non-adhesiveness of the roller surface.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-5-72881 (JP, A) JP-A-7-110615 (JP, A) JP-A-7-333915 (JP, A) JP-A-8- 39699 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03G 15/08 501

Claims (3)

(57) [Claims] 1. A developing roller which is used by being brought into contact with a photoconductor of an electrophotographic copying machine, a printer or the like, wherein a resin having a solubility parameter of less than 8.4 is a main component around a metal shaft. conductive rubber elastic layer made of the curable composition to have formed, the conductive rubber elastic
The body layer is mainly composed of a resin having a —NHCO— bond,
A developing roller coated with a surface protective layer made of a resin composition containing fine particles made of a substance containing a fluorine atom. 2. The conductive rubber elastic layer has (A) at least one alkenyl group in the molecule,
A polymer in which the repeating unit constituting the main chain is an oxyalkylene unit, (B) a curing agent having two or more hydrosilyl groups in the molecule, (C) a hydrosilylation catalyst, and (D) a conductivity-imparting agent, The developing roller according to claim 1, which is composed of a curable composition containing as a main component. 3. The surface protective layer is formed by a spray method.
The coating is applied to the surface of the conductive rubber elastic layer.
Or the developing roller described in 2.