JP2003195711A - Cleaning blade - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic cleaning blade which prevents the formation of blade traces at a copied image and can exhibit stable cleaning performance even when the cleaning blade is left standing for a long period under the high-temperature and high-humidity environment. <P>SOLUTION: The cleaning blade is formed by dispersing resin particulates consisting of a condensation polymer of a vinyl resin, fluororesin or polyester resin, etc., of 0.01 to 30 μm in number average grain size at 0.1 to 50 parts by mass into 100 parts by mass preform of polyurethane rubber. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning blade used for cleaning the surface of a photoconductor in an electrophotographic copying machine.

[0002]

2. Description of the Related Art In an image forming apparatus of an electrophotographic copying machine, an electric charge is applied to the surface of an electrophotographic organic photoconductor by discharge, and an electrostatic latent image is formed on the surface of the electrophotographic photoconductor by exposure.
Toner having a polarity opposite to that of the latent image is adhered by a developing device, developed, and then transferred to a transferred object such as paper conveyed by a charger. The toner remaining on the photosensitive drum after the transfer is removed by the cleaning blade.

In such an image forming apparatus, the cleaning blade is made of a rubber material such as urethane. Therefore, the friction coefficient of the surface of the photoconductor to the blade is large,
There is a problem that the blade scraping phenomenon occurs when removing the toner, and the toner remaining on the photoconductor cannot be removed.

To solve this problem, Japanese Patent Laid-Open No. 57-
No. 202176 and Japanese Patent Application Laid-Open No. 57-201277, there is a method in which a polysiloxane oil or a modified polysiloxane oil having reactivity is contained in the blade itself to reduce the friction coefficient and prevent curling.

Further, in Japanese Patent Laid-Open No. 4-366878,
Polyester polyols, polyether polyols and multi-polymers, which are raw materials for silicone and urethane elastomers, are added to the urethane elastomer, and the lubricity of the silicone portion of the multi-polymer reduces friction between the urethane elastomer and the photoconductor, thus cleaning Prevents blade clogging.

However, in the above conventional example, the polysiloxane oil exudes from the urethane elastomer and contaminates the photoconductor. Further, since polysiloxane oil is an insulator, there is a problem that the charge on the photoconductor becomes nonuniform due to contamination, which adversely affects the image to be copied.

Further, Japanese Patent Publication No. 07-043562 discloses a cleaning blade in which a polyurethane resin is added with a higher fatty acid ester obtained by reacting oxy- or polyoxy-ethylenebisphenol A with a higher fatty acid. .

Further, JP-A-05-224573 discloses that a silicone-containing multi-component copolymer and a carbon number of 16 to 2 are used.
A cleaning blade made from a mixture containing a saturated fatty acid amide or an unsaturated acid amide of 4, or a derivative thereof is disclosed. The publication discloses that the saturated fatty acid amide or the saturated fatty acid amide is uniformly bleeded, and the effect of reducing the friction property of the cleaning blade is brought about. However, when this blade is left in a high temperature / high humidity environment for a long period of time, a phenomenon of a blade mark on a copy image occurs due to amides uniformly bleeding from the blade.

Further, in JP-A-08-036338, a cleaning blade added with an organic lubricant is disclosed, and in JP-A-09-050221, a surface layer of a photoreceptor contains organic fine particles or inorganic fine particles, and a polyurethane is used. A cleaning method using a blade is disclosed.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide a cleaning blade having low friction and good cleaning performance for fine toner and spherical toner.

Another object of the present invention is to provide a cleaning blade capable of exhibiting stable cleaning performance without leaving a blade mark on a copy image due to long-term storage under high temperature / high humidity. .

[0012]

The above object can be achieved by the following means.

That is, the present invention is a cleaning blade for rubbing the surface of an electrophotographic photosensitive member to clean the surface of the photosensitive member, which is characterized in that fine resin particles are dispersed in a base material.

In the above invention, the following constitution is included as a preferable embodiment.

In the maximum major axis number distribution of the resin fine particles present in the cleaning blade, fine particles having a maximum major axis of 60 μm or more are 5% or less and the number average particle diameter is 0.01 to.
30 μm, 60 number% or more of fine particles exist in the particle size range of 0.3 to 3.0 times the number average particle size, or in the particle size range of 0.5 to 2.0 times the number average particle size. There are 60% by number or more of fine particles.

The resin fine particles are organic resin fine particles. Preferably, it is made of any one of vinyl resin, fluorine resin, and condensation polymer, and the condensation polymer is made of silicone resin, urethane resin, polyester resin, amide resin, phenol resin, or epoxy resin. 1 chosen
There are two or more species.

The fine resin particles contain any one of an inorganic element, oil and wax. Preferably, the inorganic element is Li, Mg, Al, Si, Ca, Ti, Mn, F
e, Co, Ni, Cu, Zn, Sr, Zr, Mo, Ce
1 or 2 or more types selected from.

The oil is preferably one or more selected from silicone oils, fluorine oils and paraffin oils.

The oil has a weight average molecular weight (Mw) of 2000 to 500,000 and a number average molecular weight (Mn) of 1000 to 30,000 Mw / Mn in a molecular weight distribution measured by gel permeation chromatography (GPC). Hereafter, more preferably, the weight average molecular weight (Mw) is 4000 to 250,000, the number average molecular weight (Mn) is 2000 to 20,000, and the Mw / Mn is 40 or less.

The wax is preferably one or more selected from paraffin wax, olefin wax, alcohol wax and ester wax.

The melting point of the wax is 20 to 150.
C., more preferably 40 to 130.degree.

The wax has a weight average molecular weight (Mw) of 500 to 20,000, a number average molecular weight (Mn) of 400 to 15,000, and a Mw / Mn of 1.05 to 10.0, and more preferably, in a molecular weight distribution measured by GPC. The weight average molecular weight (Mw) is 800 to 15,000, the number average molecular weight (Mn) is 500 to 10,000, and the Mw / Mn is 1.20 to 6.0.

The resin fine particles are added in an amount of 0.1 to 50 parts by mass with respect to 100 parts by mass of the base material.

The glass transition point of the base material is −40 to 140 ° C., and the absolute value of the difference between the glass transition point of the base material and the glass transition point of the resin fine particles is 5 ° C. or higher, more preferably 15 ° C. or higher. Further, the glass transition point of the resin fine particles is higher than the glass transition point of the base material by 15 ° C. or more.

The JIS-A hardness of the cleaning blade is 55 to 90 Hs, more preferably 55 to 85 Hs.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have ascertained the following through a detailed study.

Due to the scraping and chattering of the rubbing portion of the cleaning blade, the image quality is deteriorated due to poor cleaning, and abnormal vibration noise is generated. This is because the tip edge of the cleaning blade is pressed and remains in contact with the surface of the photoreceptor in a deformed state, as the photoreceptor rotates, frictional heat is generated, and as a result, part of the blade tip becomes soft. The contact area with the photoconductor changes subtly or the frictional heat distribution occurs in the blade longitudinal direction, and the friction coefficient distribution occurs in the blade longitudinal direction.Because the photoconductor also receives drive from the main motor. Is. This change in friction coefficient,
A slight vibration of the photoconductor that cannot be controlled starts to resonate, which causes blade clogging and chattering.

In order to solve these problems, the technology disclosed heretofore is to improve the rubber hardness of the blade, to optimize the pressing, to make the pressing uniform in the longitudinal direction of the blade, and to improve the friction coefficient as described above. In order to lower the amount, a so-called lubricant such as fatty acid amide is added to the blade and the blade surface is gradually bleeded.

The present inventors have reached the present invention on the assumption that these methods are insufficient as described above.

That is, the idea of preventing the resonance of the blade was reached by uniformly dispersing the resin fine particles in the cleaning blade. That is, by adding to the blade a substance that has a hardness different from that of the blade and is hard to bleed, concentration of shear stress applied to the blade is prevented and vibration of the blade is suppressed. Further, even if the temperature of the blade is locally increased by frictional heat, the resin fine particles suppress the elastic change, the distribution of the contact area in the longitudinal direction of the blade is kept uniform, and it is possible to prevent clogging and chattering. I understood that it was effective.

Further, by using the blade of the present invention capable of dispersing the shear stress, the pressing force on the photoconductor can be increased more than that of the conventional one, and since there is no chatter and the cleaning can be performed efficiently, It has been found that a good image can be obtained without the photoconductor drum heater used for preventing image deletion.

In order to achieve the object of the present invention, the resin fine particles used in the present invention have a number average particle diameter of 0.0 in the maximum major axis number distribution obtained by the measuring method described later.
It is preferably 1 to 30 μm, and more preferably
It is 0.1 to 10 μm.

Further, it is preferable that the resin fine particles present in the cleaning blade contain 5% by number or less of fine particles having a maximum major axis of 60 μm or more.

Further, in the maximum major axis number distribution, 60
% Of the resin particles are 0.3 times the number average particle size
It is preferable to exist in a particle size range of 3.0 times, more preferably 0.5 times to 2.0 times.

The number average particle diameter of the resin fine particles is 0.01 μm
If it is less than 3, the effect of preventing the concentration of shear stress applied to the blade is small and blade chattering easily occurs.
If it is larger than 0 μm, the distribution of shear stress in the longitudinal direction of the blade cannot be kept uniform and blade clogging is likely to occur.

The addition amount of the resin fine particles to the blade is 0.1 to 5 with respect to 100 parts by mass of the base material.
0 parts by mass is preferable, and when the addition amount of the resin fine particles is less than 0.1 parts by mass, the addition effect is small, and when it is added in excess of 50 parts by mass, the dispersion effect of the shear stress applied to the blade becomes small, and the blade clogging and Chattering occurs.

Examples of the resin material constituting the resin fine particles used in the present invention include vinyl resins, fluorine resins and condensation polymers.

Examples of the monomer constituting the vinyl resin include styrene; o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,
4-dichlorostyrene, p-ethylstyrene, 2,4-
Dimethyl styrene, pn-butyl styrene, p-te
rt-butyl styrene, pn-hexyl styrene, p
-N-octyl styrene, pn-nonyl styrene, p
Styrene derivatives such as -n-decylstyrene, pn-dodecylstyrene; ethylene, propylene, butylene,
Ethylenically unsaturated monoolefins such as isobutylene;
Unsaturated polyenes such as butadiene; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide, vinyl fluoride; vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate; methyl methacrylate, methacrylic acid Ethyl, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate. Α-methylene fatty acid monocarboxylic acid esters such as; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-acrylate
Acrylic esters such as octyl, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate; vinyl methyl ether, vinyl ethyl ether,
Vinyl ethers such as vinyl isobutyl ether; Vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone; N-vinyl compounds such as N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole and N-vinyl pyrrolidone Vinyl naphthalene; acrylic acid derivatives or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, acrylamide; These vinyl monomers are used alone or in combination of two or more.

Among these, it is preferable to use a styrene-based monomer or an acrylic-based monomer alone or in combination. Examples of vinyl resins other than the above include polyethylene-ethyl acrylate copolymer, ethylene-vinyl acetate copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, and the like.

Further, a crosslinkable monomer can be used for the purpose of improving the effect of the present invention.

As the crosslinking agent, a compound having two or more polymerizable double bonds is mainly used. For example, aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; ethylene glycol diacrylate and ethylene. Glycol dimethacrylate, 1,3
A carboxylic acid ester having two double bonds such as butanediol dimethacrylate; a divinyl compound such as divinylaniline, divinyl ether, divinyl sulfide, divinyl sulfone; and a compound having three or more vinyl groups; Used as a mixture.

Examples of the above-mentioned fluorine-based resin include copolymers of tetrafluoroethylene and perfluoroalkyl vinyl ether, copolymers of tetrafluoroethylene and hexafluoropropene, copolymers of tetrafluoroethylene and ethylene, Vinylidene fluoride homopolymer, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-hexafluoropropene copolymer, vinylidene fluoride-chlorotrifluoroethylene copolymer and chlorotrifluoroethylene At least one selected from the group consisting of copolymers of fluoroethylene and ethylene and the like can be mentioned.

Further, the fluorine-based resin may be one obtained by copolymerizing another copolymerization component within a range that does not impair the essential properties. Examples of the copolymerizable monomer component include tetrafluoroethylene, chlorotrifluoroethylene, hexafluoropropene, perfluoroalkyl vinyl ether, fluoroalkyl (C ₁ -C ₁₀ ) ethylene, perfluoroalkyl (C ₁ -C ₁₀ ) allyl. ether, formula: CF ₂ = CF _{[OCF 2 CFR f (CF 2)} p ] _q O
CF ₂ (CF ₂ ) _r Y (In the formula, R _f is a fluorine atom or a trifluoromethyl group, Y is a halogen atom, p is 0 or 1, q is an integer of 0 or 1 to 5, r is 0 or 1 to 1. An integer of 2, provided that when p is 1, R _f is a fluorine atom, and the formula is CH ₂ ═CF (CF ₂ ) _n X (where n is 0).
Is an integer of 8 and X is a hydrogen atom or a fluorine atom. )
And the like. Furthermore, examples of the fluorine-containing acrylic acid esters include fluorine-containing alcohol esters such as acrylic acid, methacrylic acid, 2-chloroacrylic acid, and 2-fluoroacrylic acid.

Preferred examples of the condensation polymer include polyester resins, polyamide resins, polyurethane resins, silicone resins, phenol resins and epoxy resins.

In the present invention, when a polyester resin is obtained by polycondensation, an alcohol and a carboxylic acid, or a derivative of a carboxylic acid such as a carboxylic acid ester or a carboxylic acid anhydride is used as a raw material monomer.

As the dihydric alcohol component, polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane and polyoxypropylene (3.
3) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.0) -2,2-bis (4
-Hydroxyphenyl) propane, polyoxypropylene (2.0) -polyoxyethylene (2.0) -2,2
-Bis (4-hydroxyphenyl) propane, polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane and other alkylene oxide adducts of bisphenol A, ethylene glycol, diethylene glycol, triethylene glycol, 1, 2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanediene methanol,
Examples include dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, bisphenol A, hydrogenated bisphenol A and the like.

Examples of trihydric or higher alcohol components include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,
2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3.
5-trihydroxymethylbenzene etc. are mentioned.

As the acid component, a divalent carboxylic acid component such as maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, succinic acid, adipic acid, sebacic acid, Azelaic acid, malonic acid, n-dodecenylsuccinic acid, isododecenylsuccinic acid, n-dodecylsuccinic acid, isododecylsuccinic acid, n-octenylsuccinic acid, n-octylsuccinic acid, isooctenylsuccinic acid, isooctylsuccinic acid, etc., Alternatively, anhydrides or lower alkyl esters of these acids may be mentioned.

Examples of the trivalent or higher carboxylic acid component include 1,2,4-benzenetricarboxylic acid and 2,5,7-
Naphthalene tricarboxylic acid, 1,2,4-naphthalene tricarboxylic acid, 1,2,4-butane tricarboxylic acid,
1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, 1,2,4-cyclohexanetricarboxylic acid, tetra (methylenecarboxyl) methane, 1,2,7, 8-
Examples thereof include octane tetracarboxylic acid, pyromellitic acid, empol trimer acid, etc., and anhydrides or lower alkyl esters of these acids.

In the present invention, when a polyester amide or polyamide is obtained by polycondensation, polyamines among the raw material monomers forming the amide component are, for example, ethylenediamine, pentamethylenediamine, hexamethylenediamine, diethylenetriamine, iminobispropylamine, Examples thereof include polyamines such as phenylenediamine, xylylenediamine, and triethylenetetramine, aminocarboxylic acids such as 6-aminocaproic acid and ε-caprolactam, and amino alcohols such as propanolamine.

As the above-mentioned polyurethane resin, polyurethane which is generally synthesized through an addition reaction with an isocyanate, a polyol and various hydrogen-containing compounds is used, and as a polyol component, a polypropylene such as polypropylene glycol or polytetramethylene glycol is used. In addition to ether-based polyols, polyester-based polyols such as adipate-based polyols, polycaprolactam-based polyols, and polycarbonate-based polyols are used, and as the isocyanate component, tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, toluidine Aromatic polyisocyanates such as diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate And an aliphatic polyisocyanate such as dicyclohexylmethane diisocyanate, and a curing agent is added. The curing agent is usually 1,4-
A dihydric alcohol such as butanediol and a trihydric or higher polyhydric alcohol such as trimethylolpropane and pentaerythritol are used in combination.

Examples of the silicone resin include organopolysiloxanes as a monomer, an alkyl group such as a methyl group, a phenyl group, an amino group, an alkoxy group, an oxime group, an acetoxy group, an epoxy group, a fluoroalkyl group,
The thing which has an alkenyl group is mentioned.

Phenolic resins include reaction products of phenol, cresol, xylenol, butylphenol, catechol and bisphenols as monomers with aldehydes such as formaldehydes, trioxane and glyoxal, and further organic ester phenol curing agents. For example, it is preferable to use formic acid esters, lactones and the like.

As the epoxy resin, it is preferable to use an epoxy-phenol novolac type, triglycidyl ether type, or polyglycol type resin which is reacted with an alcohol or an amine compound.

The resin fine particles used in the present invention may contain an inorganic element. Specifically, Li, M
g, Al, Si, Ca, Ti, Mn, Fe, Co, N
Examples thereof include i, Cu, Zn, Sr, Zr, Mo and Ce. In order to further exert the effects of the present invention, A
It is preferable to contain 1, Si, Ca, Ti, Sr, and Ce as an oxide or a hydroxide. By including such an inorganic element in the resin, the transfer residual toner adhered to the photoconductor, the fluidizing agent externally added to the toner, the paper dust generated from the transfer paper, and the filler used in the paper This is because it is effective in removing (talc, kaolin, calcium carbonate, etc.).

When the above-mentioned inorganic element is contained in the resin fine particles, the amount of the inorganic element or its oxide or hydroxide is 1.0 to 100 parts by mass of the resin material constituting the resin fine particles.
It is preferably added at a ratio of 50 parts by mass.

Further, the resin fine particles may contain oil or wax for the purpose of reducing the coefficient of friction with the photoreceptor and eliminating the phenomenon of blade marks even after being left for a long time in a high temperature / high humidity environment. good.

As the oil that can be contained in the resin fine particles, silicone oil, fluorine oil and paraffin oil are preferably used alone or in combination of two or more.

In order to obtain the effect of the present invention more effectively, the oil has a weight average molecular weight (Mw) of 2000 to 500,000 and a number average molecular weight (in the molecular weight distribution measured by gel permeation chromatography (GPC)). The Mn) is preferably 1000 to 30,000 and the Mw / Mn is 60 or less, more preferably the weight average molecular weight is 4000 to 250,000, the number average molecular weight is 2000 to 20000, and the Mw / Mn is 40 or less.

When oil is used, the viscosity of the oil is 20
In the case of a relatively low viscosity of 00 cSt (normal temperature) or lower, 0.05 to 100 parts by mass of the resin constituting the resin fine particles
It is preferable to add 10 parts by mass, preferably 0.1 to 2 parts by mass. This is because if the amount is less than 0.05 parts by mass, the effect of adding oil is scarce, and if the amount exceeds 10 parts by mass, blade marks are likely to occur. Oil viscosity is 2000 cSt
When it is higher than (normal temperature), the addition amount is 0.1 to 50 parts by mass with respect to 100 parts by mass of the resin constituting the resin fine particles,
It is more preferably 0.5 to 10 parts by mass. This is also the same as the above reason.

The wax that can be contained in the resin fine particles is preferably paraffin wax, olefin wax, alcohol wax, ester wax, or a combination of two or more thereof.

In order to obtain the effects of the present invention more effectively, the wax has a weight average molecular weight (Mw) of 500 to 20,000 and a number average molecular weight (Mn) of 400 to 15,000 in the molecular weight distribution measured by GPC. Mw / Mn
Is preferably 1.05 to 10.0, more preferably a weight average molecular weight of 800 to 15,000, a number average molecular weight of 500 to 10,000, and Mw / Mn of 1.20.
It is 6.0.

When the wax is used by being added to the resin fine particles, the melting point (mp) of the wax is 20 to 150.
C., preferably 40 to 130.degree.

The amount of wax added to the resin particles is 100 parts by mass of the resin constituting the resin particles.
0.5 to 100 parts by mass, preferably 2 to 2 parts by mass
It is preferably 5 parts by mass. If the addition amount is 0.5 parts by mass, the effect of addition is small, and if it exceeds 100 parts by mass, the wax partially adheres to the photosensitive member, and the toner developed in that part is not transferred to the transfer paper, If this state continues, a phenomenon occurs in which the toner is fused to the photoconductor.

When the above oil or wax is used, the preferred combination with the base resin material is as follows.・ Styrene-based resin oil: Silicone-based, paraffin-based wax: Paraffin-based, olefin-based, alcohol-based, ester-based acrylic resin oil: Silicone-based wax: ester-based, alcohol-polyester-based resin oil: Silicone-based wax: alcohol -Based, ester-based / polyurethane-based resin oil: silicone-based wax: alcohol-based, ester-based / silicone-based resin oil: silicone-based wax: ester-based / fluorine-based resin oil: fluorine-based

The above combination is preferable because the phenomenon of the above-mentioned blade mark can be suppressed, and further, the friction coefficient with the photoconductor can be reduced. Further preferred combinations include: styrene resin paraffin wax, olefin wax, alcohol wax, acrylic resin ester wax, alcohol wax / polyester resin silicone oil, alcohol wax, ester wax / polyurethane. Examples of the resin include silicone-based oil, alcohol-based wax, ester-based wax / silicone-based resin silicone-based oil / fluorine-based resin fluorine-based oil.

The method for producing the resin fine particles according to the present invention includes the following methods.

[Production of Vinyl-Based Resin Fine Particles] The polymerization method includes an emulsion polymerization method, a suspension polymerization method, a solution polymerization method and the like.

The emulsion polymerization method is a method in which a monomer (monomer) almost insoluble in water is dispersed as fine particles in an aqueous phase with an emulsifier, and polymerization is performed using a water-soluble polymerization initiator. In this method, the heat of reaction can be easily adjusted, and the termination reaction rate is low because the phase in which the polymerization is performed (oil phase composed of polymer and monomer) and the aqueous phase are different, resulting in a high polymerization rate. A high degree of polymerization can be obtained.

In the suspension polymerization method, the aqueous solvent 1
The amount of the monomer is preferably 100 parts by mass or less (preferably 10 to 90 parts by mass) with respect to 00 parts by mass. Examples of usable dispersants include polyvinyl alcohol, partially saponified polyvinyl alcohol, and calcium phosphate. Generally, 0.05 to 1 per 100 parts by mass of the aqueous solvent.
It is preferable to use parts by weight of the dispersant. Polymerization temperature is 50-9
Although 5 ° C. is suitable, it is appropriately selected depending on the initiator used and the target polymer.

In the emulsion polymerization method and suspension polymerization method, it is possible to control the particle size of the resin fine particles obtained by the amount of the emulsifier and the dispersant. Generally, the resin fine particles synthesized by emulsion polymerization are smaller. Further, the resin fine particles obtained here may be used as they are, but it is preferable to classify the particle size distribution by classification so that the effect of the present invention can be more exerted.

Further, the fine particles obtained by the emulsion polymerization method or the suspension polymerization method are washed with an alkali or an acid, and the emulsifier and the dispersant are contained in the resin fine particles at 5000 ppm or less, preferably 2 ppm.
It is preferable to keep it to 500 ppm or less.

In the solution polymerization method, toluene is used as a solvent,
Since a solvent such as xylene is used, the molecular weight of the obtained polymer product is not as high as that of emulsion polymerization or suspension polymerization. However, since an emulsifier and a dispersant are not used, a product with high purity can be obtained. Furthermore, since a polymerization product can be obtained particularly in a molten state of wax or the like, a resin composition uniformly dispersed in a resin is obtained. The thing is obtained. The resin obtained according to the present invention is obtained by pulverizing and classifying the resin obtained here.

[Production of Fluorine-Based Resin Fine Particles] Generally, it is produced by well-known emulsion polymerization, suspension polymerization, solution polymerization, bulk polymerization and the like. The resin obtained by the polymerization is preferably subjected to particle size distribution adjustment by pulverization / classification or only classification, as in the method described above.

[Production of Condensation Polymer Fine Particles] A general synthesis method is used. For example, when synthesizing a polyester resin, no catalyst or a tin catalyst (tin oxide, octyl tin oxide, dibutyltin oxide, etc.) is used.
Or using a tungsten-based catalyst in an autoclave 1
The polymerization reaction is carried out at 80 to 250 ° C. under reduced pressure while removing water and alcohols which are condensation products. Further, in the case of urethane type resin, amine type catalyst, tin type catalyst,
Other metal-based catalysts (lead octylate, etc.) are used.

When synthesizing a high molecular weight resin, after synthesizing a prepolymer, a crosslinkable monomer,
Alternatively, a method of adding a prepolymer and synthesizing a high molecular weight resin can also be mentioned.

As the method of incorporating the above-mentioned inorganic element, oil and wax into the resin fine particles according to the present invention, a method of adding and polymerizing at the time of resin synthesis, or a method of mixing the resin after the resin synthesis while melting is performed. Examples of the method include a method of dissolving or swelling the resin with an appropriate solvent, and adding and mixing. The method of dispersing these additives is the best, but the addition system of wax and inorganic element is
Since it is difficult to control the particle size distribution by the emulsion or suspension polymerization method, it is preferable to use this method.

Urethane rubber is preferably used as a base material for forming the cleaning blade of the present invention by adding the above-mentioned resin fine particles. In particular, a urethane rubber obtained by reacting a low molecular weight polyester with diisocyanate to synthesize a urethane prepolymer, and then further adding a diol component to obtain a synthetic reaction is more preferable because uniform rubber strength can be obtained.

The amount of the resin fine particles added to the blade is 0.1 to 50 parts by mass, and more preferably 0.3 to 20 parts by mass, relative to 100 parts by mass of the base material.

The glass transition point (Tg) of the base material of the cleaning blade of the present invention is -40 ° C to 40 ° C, more preferably -25 ° C to 25 ° C.
If the glass transition point is lower than -40 ° C, the impact resilience is low and blade eclipse is likely to occur. If the glass transition point is higher than 40 ° C, the blade is chipped because it is too hard, and the photoreceptor is scratched. Poor followability with respect to the body surface causes poor cleaning.

As a preferred embodiment of the present invention, the absolute value of the difference between the glass transition point of the base material and the glass transition point of the resin fine particles is 5 ° C. or more, preferably 15 ° C. or more, and the shear stress dispersion effect is obtained. Is desirable because it is large.

It is desirable that the glass transition point of the resin particles is higher than the glass transition point of the base material by 15 ° C. or more.

The cleaning blade containing resin fine particles according to the present invention preferably has a JIS-A hardness of 55 to 90 Hs, more preferably 55 to 85 Hs.

The methods for measuring physical properties according to the present invention will be described below.

[Glass Transition Point of Base Material and Resin Fine Particles, Melting Point of Wax] The glass transition point (Tg) is a differential thermal analysis measuring device (DSC measuring device, “DSC” manufactured by Perkin Elmer Co., Ltd.).
-7 ").

If the measurement sample is 1 mm or less, it is used as it is, and if it is larger than that, it is crushed,
It is made finer than 1 mm. As the base material, a sample is used in which a blade containing no resin particles is prepared and the blade is cut with a cutter knife or the like.

The measurement sample is 5 to 20 mg, preferably 10
Precisely weigh mg. This is placed in an aluminum pan, and an empty aluminum pan is used as a reference, and measurement is performed at a temperature rising rate of 10 ° C./min at room temperature / normal humidity in a measurement temperature range of −50 ° C. to 200 ° C. Assuming this temperature increase, a temperature of 40-1
The endothermic peak of the main peak in the range of 50 ° C is obtained. At this time, the temperature corresponding to the intersection of the line at the midpoint of the baseline before and after the appearance of the endothermic peak and the differential heat curve is defined as the glass transition point (Tg).

In the case of wax, a gradual endothermic peak appears as shown in FIG. 1, so the temperature at that peak is taken as the melting point (mp).

[Molecular Weight Distribution of Oil and Wax] The cleaning blade was cut into small pieces, and a toluene solvent was used for 150.
Extract for 10 hours or more at ℃. Wax in the extract,
Methanol, which is a poor solvent for the resin, is added to precipitate and separate from the oil.

Toluene / methanol is evaporated to leave the residue as an oil, and the residue is dissolved in tetrahydrofuran (THF) to obtain a molecular weight measurement sample by GPC.

It is considered that the blade and a part of the resin fine particles remain in the filtration residue.
Thoroughly wash or soxhlet-extract the above residue (blade, a part of the resin fine particles) with THF as a good solvent. The residue was used as a wax molecular weight measurement sample.
-Dissolve in dichlorobenzene.

Conditions for measuring molecular weight of oil Device: GPC-150C (manufactured by Waters) Column: KF801-7 (manufactured by Showdex) 7 consecutive temperatures: 40 ° C. Solvent: THF (tetrahydrofuran) Flow rate: 1.0 ml / min. Sample: 0.1 ml of a sample with a concentration of 0.05 to 0.6 mass%
Injection

Wax GPC measurement condition device: GPC-150C (manufactured by Waters) Column: GMH-HT (manufactured by Tosoh Corporation) Dual temperature: 135 ° C. Solvent: o-dichlorobenzene (added 0.1% ionol) Flow rate: 1.0 ml / min. Sample: Inject 0.4 ml of a sample with a concentration of 0.15 mass%

The molecular weight distribution is measured under the above conditions, and the molecular weight calibration curve prepared from the monodisperse polystyrene standard sample is used for calculating the molecular weight of the sample.

[Maximum major axis number distribution of resin fine particles] The resin fine particles according to the present invention have a matrix-domain structure because they are incompatible with the base material of the blade.

The maximum major axis of the resin fine particles is measured by using a microtome or the like to make a blade containing the resin fine particles into a thin piece having a thickness of 0.5 mm and observing it with an optical microscope. When it is difficult to observe the interface between the base material and the resin particles (for example, a combination of urethane rubber base material and urethane resin particles), dissolve a dye such as rhodamine in an appropriate solvent, and blade under an appropriate temperature condition. Is soaked and dyed, and the resin fine particles are discriminated by the density of the dyeing. One visual field is a range that can be seen at a magnification of 500 times with an optical microscope. Observe 100 or more resin fine particles in 3 fields or more and scan the maximum major axis (one straight line is scanned, and the line connecting the intersections with the line showing the outline of the resin fine particles does not protrude from the outline 1 The longest one) counts the number of particles of 60 μm or more.

As needed (in measuring the maximum major axis)
You may change the magnification of the microscope. (Maximum major axis is 60
The maximum major axis of the resin fine particles according to the present invention is 60.
It is the number% of particles having a size of μm or more.

[Average Particle Diameter of Resin Fine Particles] A measurement sample was prepared in the same manner as described above, the maximum major axis of 100 or more resin fine particles was measured, the number average particle diameter thereof was calculated, and the value was calculated as the number of resin fine particles. The average particle size is used.

[0099]

EXAMPLES The present invention will be further described below with reference to examples. In the following examples, the "average particle size" is the "number average particle size".

(Production Example 1 of resin fine particles) 100 parts by mass of styrene (St) 0.5 part by mass of divinylbenzene (DVB) 0.5 part by mass of benzoyl peroxide were mixed, and 1 part by mass of polyvinyl alcohol was added to an aqueous system. Part was added as a dispersant, and suspension polymerization was carried out at 70 ° C. for 16 hours. After the polymerization, the polymer was dried by washing with an alkali to remove the dispersant. After drying, air classification was performed to obtain resin fine particles 1 having an average particle diameter of 0.5 μm.

(Production Example 2 of resin fine particles) -terephthalic acid (TPA) 42 mol% -trimellitic anhydride (TMA) 10 mol% -polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) Propane (BPA) 48 mol% was used, stannous oxide was used 0.5% by mass as a catalyst,
Condensation polymerization was carried out at 200 ° C. for 8 hours under reduced pressure to obtain a polyester resin. This is crushed and classified to have an average particle size of 4
Resin fine particles 2 of μm were obtained.

(Production Example 3 of resin fine particles) terephthalic acid,
After synthesizing a polyester polyol using propylene glycol (PG), tolylene diisocyanate was reacted with an amine catalyst to obtain a polyurethane resin. This was crushed and classified to obtain urethane resin particles 3 having an average particle diameter of 8 μm.

(Production Example 4 of fine resin particles) Epoxy-modified phenylmethyl silicone varnish (Ph.Me.Si) was used in combination with hexamethylolmelamine, and a curing reaction was performed while granulating by a spray drying method, and a silicone having an average particle size of 5 μm was used. A resin fine particle 4 was obtained.

(Production Example 5 of resin fine particles) 20 parts by mass of trifluoroethyl methacrylate monomer, 30 parts by mass of methyl methacrylate monomer (MMA), 5 parts of styrene monomer
0 parts by mass of azobisisobutyronitrile initiator
By mass addition, a fluororesin was obtained. This resin was pulverized and classified to obtain fluororesin fine particles 5 having an average particle diameter of 1 μm.

(Production Example 6 of resin fine particles) In Production Example 4 of resin fine particles, 100 parts by mass of the silicone varnish had a weight average molecular weight (Mw) of 42,000 and a number average molecular weight (M
n) was 10,000, Mw / Mn was 4.2, and the viscosity was 10,000 cSt. 5 parts by mass of diphenyl silicone oil was added, and cured in the same manner as in Production Example 4 by a spray drying method to obtain an average particle diameter. To obtain 4 μm of silicone oil-containing silicone resin fine particles 6.

(Production Examples 7 to 9 of Resin Fine Particles) Resin fine particles having different glass transition points and different average particle sizes as shown in Table 1 by changing the composition ratio of styrene and 2-ethylhexyl acrylate (2-EHA). 7-9 were obtained.

(Production Example 10 of fine resin particles) Except that a polyester polyol was synthesized using terephthalic acid, adipic acid, and ethylene glycol, the same procedure as in Production Example 3 of fine resin particles was conducted.
I got 0.

(Production Examples 11 to 19 of resin fine particles) Polymerization was carried out using styrene and butyl methacrylate (BMA),
This was pulverized and classified to obtain resin fine particles 11 to 19 having different average particle diameters as shown in Tables 1 and 2.

(Production Example 20 of resin fine particles) The resin obtained in Production Example 11 of resin fine particles was added with a weight average molecular weight (Mw).
Is 2800, the number average molecular weight (Mn) is 1800, Mw /
Polyethylene wax having Mn of 1.6 and a melting point of 115 ° C. was melt-kneaded by a biaxial extrusion kneading device, cooled, and then pulverized and classified to obtain resin fine particles 20.

(Production Examples 21 to 23 of Resin Fine Particles) The weight average molecular weight (M
w) is 1800, number average molecular weight (Mn) is 1000, M
Alcohol wax having a w / Mn of 1.8 and a melting point of 105 ° C., SrTiO ₃ and CeO ₂ are added, melt-kneaded in a biaxial extrusion kneading device, cooled, and then pulverized and classified to obtain resin fine particles 21. ~ 23 was obtained.

Example 1 4,4′-diphenylmethane diisocyanate 100 parts by mass Polyester diol (hydroxyl value = 113.0) 80 parts by mass (ethylene glycol / adipic acid) Polyester diol (hydroxyl value = 55.1) ) 120 parts by mass (ethylene glycol / adipic acid) are reacted in a nitrogen atmosphere to give a weight average molecular weight (Mw) of 4
A prepolymer A having a molecular weight of 500 and a number average molecular weight (Mn) of 1800 was synthesized.

Prepolymer A 100 parts by mass Styrene resin fine particles 1 5 parts by mass Mixture of 1,4-butanediol and 1,1,1-trimethylolpropane (weight ratio = 70: 30) 8.5 After sufficiently stirring and mixing parts by mass, the mixture was poured into a mold for molding a cleaning blade and cured at 130 ° C., and after the curing was completed, the mold was removed to obtain a cleaning blade 1 of this example. The characteristics are shown in Table 2.

When the Tg of the blade 1 was measured by DSC, inflection points due to heat absorption were observed at 0 ° C and 100 ° C.

A cleaning blade 2 of Comparative Example 1 was prepared in the same manner as above except that the fine styrene resin particles were removed. The Tg of the blade 2 (that is, the Tg of the base material of the blade 1) was measured by DSC, and it was 0 ° C.

Using the cleaning blade 1 described above, a copying test was carried out by a copying machine which was modified from the digital copying machine "GP-40" manufactured by Canon Inc. by the evaluation method shown below. As a result, good results as shown in Table 1 were obtained. Results were obtained.

(Examples 2 to 23) The same procedure as in Example 1 was carried out except that the resin fine particles 1 were replaced with the resin fine particles 2 to 23.
When a cleaning blade having the characteristics shown in Table 2 was prepared and a copy test was conducted, good results as shown in Table 3 were obtained.

Comparative Example 1 The cleaning blade 2 containing no resin fine particles described in Example 1 was used.
A copy test was conducted in the same manner as in, and the results are shown in Table 3.

(Comparative Example 2) A cleaning blade was prepared in the same manner as in Example 1 except that the resin fine particles were changed to 5 parts by mass of silicone oil, and a copy test was conducted. The results shown in Table 3 were obtained. Was given.

(Comparative Example 3) In Example 1, the composition ratio of the base material was changed and the curing temperature was set to 100 without using the resin fine particles.
C., and a cleaning blade having a glass transition point (Tg) of −45 ° C. was obtained.

Using this blade, a copying test was conducted in the same manner as in Example 1, and the results shown in Table 1 were obtained.

[Evaluation Method] Room temperature / low humidity (N / L: 23.
Under the environment of 5 ° C./5% RH), 10,000 sheets of images were subjected to a durability test. In the meantime, blade scraping, abnormal noise, cleaning property, toner fusion to the photoconductor, scraped amount of photoconductor surface layer (after printing 10,000 sheets), photoconductor surface scratch by halftone image (10,000 sheets printed) After the check). The amount of abrasion of the surface layer of the photoconductor was determined from the measured value of the surface current layer of the photoconductor before and after image formation.

After completion of the evaluation in a room temperature / low humidity environment, further high temperature / high humidity (H / H: 35 ° C./80% RH)
After being left in the environment for 24 hours, it was evaluated whether or not the first character of the image was clearly copied (image deletion evaluation). In addition, for 6 days (total 1
After leaving for a week, the cleaning blade trace was evaluated.
After that, the test piece was left for 1 week in an environment of 45 ° C., a test was performed on 1000 sheets, and the clogging condition of the waste toner discharge pipe was evaluated by measuring the toner weight in the pipe.

[Evaluation Criteria] A rating of ⊚, ◯, ◯ Δ, Δ, Δx, and x was given in 6 grades, with ⊚ as the best and x as the worst.
Incidentally, ⊚ to Δ are practical, and Δ × to × are impractical.
The scratches on the surface of the photoconductor after printing 10,000 sheets and the marks of the blade after leaving for 1 week were evaluated as ◯: none and x: present.

[0124]

[Table 1]

[0125]

[Table 2]

[0126]

[Table 3]

[0127]

EFFECT OF THE INVENTION According to the cleaning blade of the present invention, cleaning such as removal of residual toner on the surface of the photosensitive member is efficiently and favorably carried out, and blade marks are left on the copied image even when left standing for a long time under high temperature and high humidity. Stable cleaning performance can be obtained without causing problems such as occurrence.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of an endothermic peak in a method for measuring a melting point of wax according to the present invention.

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Claims (29)

[Claims] 1. A cleaning blade for rubbing the surface of an electrophotographic photosensitive member to clean the surface of the photosensitive member, wherein the cleaning blade comprises resin particles dispersed in a base material. 2. In the maximum major axis number distribution of the resin fine particles present in the cleaning blade, the maximum major axis is 60 μm.
The cleaning blade according to claim 1, wherein the fine particles are 5% by number or less. 3. The cleaning according to claim 1, wherein the number average particle diameter of the resin fine particles is 0.01 to 30 μm in the maximum major axis number distribution of the resin fine particles present in the cleaning blade. blade. 4. The maximum major axis number distribution of the resin fine particles present in the cleaning blade is 60 number% in a particle size range of 0.3 to 3.0 times the number average particle size of the resin fine particles.
4. The above fine particles are present.
The cleaning blade according to any one of 1. 5. The maximum major axis number distribution of the resin fine particles present in the cleaning blade is 60 number% in a particle diameter range of 0.5 to 2.0 times the number average particle diameter of the resin fine particles.
4. The above fine particles are present.
The cleaning blade according to any one of 1. 6. The cleaning blade according to claim 1, wherein the resin fine particles are organic resin fine particles. 7. The cleaning blade according to claim 6, wherein the resin fine particles are made of vinyl resin. 8. The cleaning blade according to claim 6, wherein the resin fine particles are made of a fluororesin. 9. The cleaning blade according to claim 6, wherein the resin fine particles are made of a condensation polymer. 10. The condensation polymer is a silicone resin,
Urethane resin, polyester resin, amide resin,
The cleaning blade according to claim 9, which is one kind or two or more kinds selected from a phenolic resin and an epoxy resin. 11. The cleaning blade according to claim 1, wherein the resin fine particles are resin fine particles containing an inorganic element. 12. The inorganic element is Li, Mg, Al or S.
i, Ca, Ti, Mn, Fe, Co, Ni, Cu, Z
1 or 2 selected from n, Sr, Zr, Mo and Ce
The cleaning blade according to claim 11, wherein the cleaning blade is more than one kind. 13. The cleaning blade according to claim 1, wherein the resin fine particles contain oil. 14. The cleaning blade according to claim 13, wherein the oil is one kind or two or more kinds selected from silicone oil, fluorine oil, and paraffin oil. 15. The oil has a weight average molecular weight (Mw) of 2000 to 500,000 and a number average molecular weight (Mn) of 1,000 to 30,000 Mw / Mn of 60 in terms of molecular weight distribution measured by gel permeation chromatography (GPC). The cleaning blade according to claim 13 or 14, characterized in that: 16. The oil has a weight average molecular weight (Mw) of 4,000 to 250,000, a number average molecular weight (Mn) of 2,000 to 20,000 Mw / Mn of 40 or less in a molecular weight distribution measured by GPC. The cleaning blade according to claim 13 or 14, which is characterized in that. 17. The cleaning blade according to claim 1, wherein the resin fine particles contain wax. 18. The cleaning blade according to claim 17, wherein the wax is one or more selected from paraffin wax, olefin wax, alcohol wax, and ester wax. 19. The melting point of the wax is 20 to 150 ° C.
The cleaning blade according to claim 17 or 18, wherein 20. The melting point of the wax is 40 to 130 ° C.
The cleaning blade according to claim 17 or 18, wherein 21. The wax has a weight average molecular weight (Mw) of 500 to 20,000, a number average molecular weight (Mn) of 400 to 15,000, and a Mw / Mn of 1.05 to 10.0 in a molecular weight distribution measured by GPC. The cleaning blade according to any one of claims 17 to 20, characterized in that: 22. The wax has a weight average molecular weight (Mw) of 800 to 15,000, a number average molecular weight (Mn) of 500 to 10,000, and a Mw / Mn of 1.20 to 6.0 in a molecular weight distribution measured by GPC. The cleaning blade according to any one of claims 17 to 20, characterized in that: 23. The cleaning blade according to claim 1, wherein 0.1 to 50 parts by mass of the resin fine particles are added to 100 parts by mass of the base material. 24. The glass transition point of the base material is -40 to 140.
The cleaning blade according to any one of claims 1 to 23, wherein the cleaning blade has a temperature of ° C. 25. The cleaning blade according to claim 1, wherein the absolute value of the difference between the glass transition point of the base material and the glass transition point of the resin fine particles is 5 ° C. or higher. 26. The cleaning blade according to claim 1, wherein the absolute value of the difference between the glass transition point of the base material and the glass transition point of the resin fine particles is 15 ° C. or higher. 27. The cleaning blade according to claim 26, wherein the glass transition point of the resin fine particles is 15 ° C. or more higher than the glass transition point of the base material. 28. The JIS-A hardness of the cleaning blade is 55 to 90 Hs.
27. The cleaning blade according to any one of 27. 29. The JIS-A hardness of the cleaning blade is 55 to 85 Hs.
27. The cleaning blade according to any one of 27.