JP2005352072A - Developing roller and image forming apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing roller which is light in weight, is capable of obtaining higher quality image and has such an excellent durability as not to cause defective image such as fogging of white image, roughness of halftone image or gradation irregularity of black image even when used for a long time, and to provide an image forming apparatus using the developing roller. <P>SOLUTION: The developing roller 1 comprises a shaft member 2 composed of a metallic pipe and one or more layers of resin layers 4 arranged on the outside in the radial direction. Therein, universal hardness on the measurement condition of 100 mN/mm<SP>2</SP>/60sec with respect to the outer circumferential surface of the roller is ≤3N/mm<SP>2</SP>. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a developing roller used in an image forming apparatus such as an electrophotographic apparatus such as a copying machine or a printer or an electrostatic recording apparatus, and an image forming apparatus using the developing roller.

  In an electrophotographic image forming apparatus such as a copying machine or a printer, a nonmagnetic developer (toner) is supplied to a latent image holding body such as a photosensitive drum holding a latent image, and toner is applied to the latent image on the latent image holding body. The latent image is visualized by adhering, and as one of the general development methods, on the outer periphery of the developing roller arranged with a small gap between the latent image holding member and the latent image holding member. There is a non-magnetic jumping development method in which charged toner is carried, and the developing roller is rotated in a state where a voltage is applied between the latent image holding member and the developing roller, thereby causing the toner to fly to the latent image holding member.

  The nonmagnetic jumping development method will be further described with reference to FIG. A small gap 92 is provided with respect to the photosensitive drum 95 between the toner supply roller 94 for supplying the toner and the photosensitive drum (latent image holding member) 95 holding the electrostatic latent image. The developing roller 91, the photosensitive drum 95, and the toner supply roller 94 rotate in the directions of the arrows in the drawing, and a predetermined voltage is applied between the photosensitive drum 95 and the developing roller 91. The toner 96 is supplied to the surface of the developing roller 91 by the toner supply roller 94, the toner 96 is adjusted to a uniform thin layer by the stratifying blade 97, and the toner 96 formed in the thin layer is exposed to the gap 92. It flies to the drum 95 and adheres to the latent image, and this latent image is visualized.

  In the figure, reference numeral 98 denotes a transfer unit, which transfers a toner image onto a recording medium such as paper. A cleaning unit 99 is configured to remove the toner 6 remaining on the surface of the photosensitive drum 95 after the transfer by the cleaning blade 99a.

  FIG. 2 is a cross-sectional view showing a conventional developing roller 91 used in the non-magnetic jumping developing method. The developing roller 91 is generally a solid columnar or hollow cylinder made of a highly conductive material such as metal. A resin layer 84 for optimizing the chargeability and adhesion to the toner or the frictional force between the developing roller and the stratified blade is provided on the outer periphery of the shaft member 82 (for example, Patent Documents). 1).

The shaft member 82 is preferably light in weight as long as it is permitted in terms of strength. Therefore, it is preferable that the shaft member 82 has a hollow cylindrical shape. In this case, the metal pipe 85 and the metal pipe 85 are attached to both ends of the metal pipe 85, respectively. These shaft caps 86 are provided with shaft portions 86a that constitute both ends of the shaft member 82 in the longitudinal direction, and are supported by roller support portions of the image forming apparatus.
JP 2002-14534 A

  However, in recent years, the demand for image formability has become stricter due to higher speed of printers, improvement of required image fineness, or color imaging, and various problems that cannot be handled by conventional developing rollers have become apparent. . In particular, the uniformity of image quality becomes more demanding, and when the number of printed sheets is increased by incorporating a developing roller into an image forming apparatus for a long period of time, the fogging of a white image or the roughness of a halftone image, Alternatively, there is a problem that image defects such as dark and light unevenness of a black image occur.

  The present invention has been made in view of such problems, and even higher quality images can be obtained. Even when used for a long period of time, fogging of a white image, roughness of a halftone image, or shading of a black image can be achieved. It is an object of the present invention to provide a developing roller excellent in durability that does not cause image defects such as unevenness, and an image forming apparatus using the developing roller.

<1> The present invention provides a latent image carrier having a non-magnetic developer having one or more resin layers on the outer side in the radial direction of a shaft member that is attached by being axially supported at both ends in the length direction, and carried on the outer peripheral surface. In the developing roller supplied to
Together with the shaft member and made from a metal pipe, for the roller outer peripheral surface, the measurement conditions of 100mN / mm ^2/60 seconds, 5 [mu] m indentation when the universal hardness is the developing roller is 3N / mm ² or less .

<2> The present invention is the developing roller according to <1>, wherein the universal hardness is 0.1 to 3 N / mm ² when pressed against the outer peripheral surface of the roller by 5 μm under the previous measurement conditions.

  <3> The present invention is the developing roller according to <1> or <2>, in which an elastic layer is disposed between the roller body and the resin layer located on the radially innermost side.

  <4> The present invention is the developing roller according to <3>, wherein the elastic layer contains ethylene-propylene rubber, butadiene rubber, silicone rubber, urethane rubber, or a mixture of these and other rubber materials.

  <5> The present invention is the developing roller according to claim 5, wherein the elastic layer contains a resin having a urethane bond in <3>.

<6> The present invention is the developing roller according to any one of <1> to <5>, wherein at least one resin layer is made of an ultraviolet curable resin or an electron beam curable resin containing a conductive agent.
In this specification, the electron beam curable resin does not contain a crosslinking agent, a polymerization initiator, or a cleavage aid, and has the property of allowing self-crosslinking to proceed with energy by electron beam irradiation without using these aids. It shall mean the resin it has. However, in actual production, these may be blended with a crosslinking agent or the like to form a layer, and the electron beam curable resin does not refuse to blend them with the crosslinking agent or the like.

  <7> In the present invention, in any one of <1> to <6>, at least one resin layer is formed by applying a solvent-free coating solution and irradiating with ultraviolet rays or electron beams. Laura.

  <8> The present invention is the developing roller according to any one of <1> to <7>, wherein the total thickness of the resin layer is 1 to 500 μm.

  <9> The present invention is an image forming apparatus provided with the developing roller according to any one of <1> to <8>.

According to the invention of <1>, for the roller outer peripheral surface, the measurement conditions of 100mN / mm ^2/60 seconds, since the universal hardness against penetration depth of 5μm was 3N / mm ² or less, reducing the pressure to the toner In addition to obtaining an extremely high quality image, the stress applied when the toner on the surface of the developing roller slides can be reduced, and the toner damage caused by this stress can be suppressed to provide stable toner charging performance over a long period of time. I can.

According to the invention <2>, since the universal hardness at the time of 5 μm indentation with respect to the outer peripheral surface of the roller is 0.1 to 3 N / mm ² , the roller surface hardness is further optimized to charge the toner. Further long-term stability of performance can be ensured.
It can be.

  According to the invention <3>, since the elastic layer is disposed between the roller main body portion and the resin layer located on the radially innermost side, the resin layer is pressed against the latent image holding member or the stratified blade. Thus, the stress applied to the resin layer can be reduced, the durability of the resin layer can be improved, and the stress on the toner can be reduced. This can contribute to the formation of a stable image over a long period of time. .

  In addition to the jumping method, the developing method using non-magnetic toner includes a pressure developing method in which the developing roller is pressed against the latent image carrier and developed. This developing roller was used for the pressure developing method. In this case, the stress from the latent image carrier can be relieved, which can further contribute to the durability of the resin layer and the long-term development performance.

  According to the invention of <4>, since the elastic layer contains ethylene-propylene rubber, butadiene rubber, silicone rubber, urethane rubber or a mixture of these and other rubber materials, an appropriate surface elasticity can be obtained. it can.

  According to the invention <5>, since the elastic layer contains a resin having a urethane bond, it is possible to achieve both an appropriate strength and an appropriate surface elasticity. Both degradations can be suppressed.

  According to the invention <6>, since at least one resin layer is made of an ultraviolet curable resin or an electron beam curable resin containing a conductive agent, heat or hot air is used instead of ultraviolet irradiation or electron beam irradiation. Compared to forming by drying and curing, it can save a lot of equipment and space for drying, and also suppress variation in film formation due to difficult control of drying process In addition, the resin layer can be formed with high accuracy.

  According to the invention <7>, since at least one resin layer is formed by applying a solvent-free coating solution and irradiating ultraviolet rays or electron beams, the same effects as described above can be brought about.

  In the invention <8>, the total thickness of the resin layer is 1 to 500 μm, and when the thickness is less than 1 μm, the charging performance of the surface layer is sufficiently ensured by friction during long-term use. On the other hand, when the thickness exceeds 500 μm, the surface of the developing roller becomes hard and damages the toner, causing the toner to adhere to an image forming body such as a photosensitive member or a stratified blade, resulting in an image defect. It may become.

  According to the invention <9>, the development roller according to any one of <1> to <8> is provided, so that a light weight and higher quality image can be obtained and used for a long time. In addition, it is possible to have a developing roller having excellent durability that does not cause image defects such as fogging of a white image, roughness of a halftone image, or unevenness of density of a black image.

  The embodiment of the present invention will be described in more detail. FIG. 3A is a cross-sectional view showing the developing roller of the present embodiment, and FIG. 3B is a side view corresponding to the view taken along the line bb in FIG. The developing roller 1 is formed by forming a semiconductive elastic layer 3 on the outer periphery of the shaft member 2 and further forming a semiconductive resin layer 4 on the elastic layer 3. The elastic layer 3 is essential. Not a configuration. The shaft member 2 includes a hollow cylindrical metal pipe 5 and caps 6 having shafts attached to both ends of the metal pipe 5, and the shaft caps serving as both longitudinal ends of the shaft member 2. 6 is provided with shaft portions 6a constituting both ends in the length direction of the shaft member 2, and is supported by a roller support portion of an image forming apparatus (not shown).

  The shaft member 2 is made of metal and has good conductivity. Although it does not specifically limit as a metal material used for the shaft member 2, For example, iron, stainless steel, aluminum, an alloy containing these, etc. can be used.

  As long as the thickness of the pipe is sufficient in strength, it is preferably thinner in terms of weight reduction, and can be set to, for example, 0.3 to 2 mm. In order to assemble the metal pipe 5 and the shaft cap 6, for example, as shown in FIG. 3B, a convex portion 5a provided on the metal pipe 5 and a concave portion 6b provided on the shaft cap 6 are provided. And the metal pipe 5 and the shaft cap 6 may be fixed by an adhesive, pinning or the like.

The developing roller 1 is for the roller outer peripheral surface, the measurement conditions of 100mN / mm ^2/60 seconds, indentation depth is 5μm state, i.e., a universal hardness in a state of being deformed roller outer surface inwardly only 5μm 3 N / mm ² or less.

The universal hardness is a physical property value obtained by pushing an indenter into a measurement object while applying a load.
(Test load) / (Indenter surface area under test load)
And the unit is expressed in N / mm ² . The universal hardness can be measured using, for example, a commercially available hardness measuring device such as an ultra micro hardness tester H-100V manufactured by Fischer. In this measuring device, a square or triangular pyramid-shaped indenter is pushed into the object to be measured while applying a test load, and when the predetermined indentation depth is reached, the surface area with which the indenter is in contact is obtained from the indentation depth. The universal hardness is obtained from the above formula. That is, when the indenter is pushed into the object to be measured under the constant load measuring condition, the stress at that time with respect to the pushed-in depth is defined as universal hardness.

In the developing roller 1 of the present invention, the universal hardness of 3N / mm ² or less at measurement conditions 100mN / mm ^2/60 seconds in the universal hardness measurement, preferably 0.1~3N / mm ^2, particularly preferably 0. The surface of the developing roller is adjusted to 1 to 1.5 N / mm ² .

The developing roller 1 of the present invention has the measurement conditions defined above in the vicinity of the surface thereof, preferably in the region within 5 μm from the surface (that is, the constant load application speed 100/60 (mN / mm ² / sec) in the universal hardness measurement). ) Is 3 N / mm ² or less, as described above. Here, when the universal hardness exceeds 3 N / mm ² , the toner is greatly deteriorated, and it becomes difficult to obtain a stable and high-quality image over a long period of time.

  That is, the universal hardness required under the above conditions is an index for directly evaluating the hardness in an area preferably within 5 μm from the outer peripheral surface of the developing roller 1, and is extremely effective in judging the physical properties of the developing roller.

  Conventionally used Asker C hardness, JIS A hardness, Micro Hardness, etc. are for measuring stresses in relatively large deformations, whereas the universal hardness defined here has a surface of only 5 μm at most. It represents the stress when it is deformed. The average particle size of the toner used in the nonmagnetic development process is about 4 to 10 μm, and the toner is pressed against the surface of the developing roller by a stratified blade disposed with a slight gap from the surface of the developing roller. At this time, a deformation corresponding to the average particle diameter of the toner occurs on the surface of the developing roller, and if the stress on the surface of the developing roller in this deformation is large, the stress applied to the toner becomes large. Deterioration of the residual toner occurs, resulting in a problem that normal toner charging performance cannot be carried. As a result, image quality such as image fogging and a decrease in print density is impaired. The present invention is intended to suppress toner deterioration by reducing the stress when the surface of the developing roller is deformed by 5 μm to a predetermined value or less in order to reduce the stress due to the minute deformation.

  Here, the resin layer 4 is composed of one layer or a plurality of layers, and at least one of them is composed of an ultraviolet curable resin or an electron beam curable resin containing a conductive agent.

  The resin layer 4 can give a required charge amount to the toner and obtain a required toner conveyance amount according to the specifications of the toner and the image forming apparatus, and also requires a toner supply amount to the latent image holding member. Characteristics such as electric resistance and surface properties are set so as to be the same.

  As the resin layer 4, those having an insoluble content with respect to a solvent (a good solvent such as acetone) of 70% by weight or more are preferably used. When the solvent-insoluble content is less than 70% by weight, a single molecular weight shift occurs in the pressure contact portion of another member that is in contact with the developing roller such as an image forming body or a stratified blade due to standing for a long period of time. There is a risk of malfunction. From such a point, the solvent-insoluble content is particularly preferably 80% by weight or more.

  Examples of the ultraviolet curable resin or electron beam curable resin forming the resin layer 4 include polyester resin, polyether resin, fluorine resin, epoxy resin, amino resin, polyamide resin, acrylic resin, acrylic urethane resin, urethane resin, and alkyd resin. , Phenol resin, melamine resin, urea resin, silicone resin, polyvinyl butyral resin, and the like. These can be used alone or in combination. Furthermore, modified resins in which specific functional groups are introduced into these resins can also be used.

  Although it does not specifically limit as an ultraviolet curable resin or an electron beam curable resin, The (meth) acrylate type resin composition containing a (meth) acrylate oligomer is suitable.

  Examples of such (meth) acrylate oligomers include urethane (meth) acrylate oligomers, epoxy (meth) acrylate oligomers, ether (meth) acrylate oligomers, ester (meth) acrylate oligomers, and polycarbonate (meth) acrylate oligomers. And fluorine-based and silicone-based acrylic oligomers.

  The (meth) acrylate oligomer includes polyethylene glycol, polyoxypropylene glycol, polytetramethylene ether glycol, bisphenol A type epoxy resin, phenol novolac type epoxy resin, an adduct of polyhydric alcohol and ε-caprolactone, and the like ( It can be synthesized by reaction with (meth) acrylic acid or by urethanizing a polyisocyanate compound and a (meth) acrylate compound having a hydroxyl group.

  A urethane type (meth) acrylate oligomer is obtained by urethanizing a polyol, an isocyanate compound, and a (meth) acrylate compound having a hydroxyl group.

  Examples of the epoxy-based (meth) acrylate oligomer may be any reaction product of a compound having a glycidyl group and (meth) acrylic acid. Among them, a benzene ring, a naphthalene ring, a spiro ring, a dicyclopentadiene, A reaction product of a compound having a cyclic structure such as tricyclodecane and having a glycidyl group and (meth) acrylic acid is preferred.

  Furthermore, ether-based (meth) acrylate oligomers, ester-based (meth) acrylate oligomers and polycarbonate-based (meth) acrylate oligomers react with polyols (polyether polyols, polyester polyols and polycarbonate polyols) and (meth) acrylic acid, respectively. Can be obtained by:

  The resin composition for forming the resin layer 4 is blended with a reactive diluent having a polymerizable double bond for viscosity adjustment as necessary. As such a reactive diluent, for example, a monofunctional, difunctional or polyfunctional polymerizable compound having a structure in which (meth) acrylic acid is bonded to a compound containing an amino acid or a hydroxyl group by an esterification reaction or an amidation reaction Etc. can be used. These diluents are usually preferably used in an amount of 10 to 200 parts by weight per 100 parts by weight of the (meth) acrylate oligomer.

  As the conductive agent blended in the resin of the resin layer 4, an electronic conductive agent, an ionic conductive agent, or the like is used.

  Examples of the electronic conductive agent include conductive carbon such as ketjen black and acetylene black, rubber carbon such as SAF, ISAF, HAF, FEF, GPF, SRF, FT, and MT, and a color treated with oxidation ( Ink) carbon, pyrolytic carbon, natural graphite, artificial graphite, antimony-doped tin oxide, titanium oxide, zinc oxide, nickel, copper, silver, germanium and other metals and metal oxides, polyaniline, polypyrrole, polyacetylene, etc. Conductive whiskers such as conductive polymer, carbon whisker, graphite whisker, titanium carbide whisker, conductive potassium titanate whisker, conductive barium titanate whisker, conductive titanium oxide whisker, and conductive zinc oxide whisker.

The blending amount of these electronic conductive agents is preferably 100 parts by weight or less, for example, 1 to 100 parts by weight, particularly 1 to 80 parts by weight, especially 10 to 50 parts by weight, based on 100 parts by weight of the resin.
However, when the carbon-based conductive agent is contained in the ultraviolet curable resin, it is preferably 20 parts by weight or less, particularly 10 parts by weight or less, especially 5 parts by weight or less, based on 100 parts by weight of the resin, and 20 parts by weight. Since the carbon-based conductive agent easily absorbs ultraviolet rays when the amount exceeds the upper limit, the larger the amount of the conductive agent, the more difficult it is for the ultraviolet rays to reach the back of the layer, so that the progress of the ultraviolet curing reaction may not proceed sufficiently. is there.

  Examples of ionic conductive agents include perchlorate, chlorate, hydrochloride, bromine such as tetraethylammonium, tetrabutylammonium, dodecyltrimethylammonium, hexadecyltrimethylammonium, benzyltrimethylammonium, and modified fatty acid dimethylethylammonium. Ammonium salts such as acid salts, iodates, borofluoride salts, sulfates, ethyl sulfates, carboxylates, sulfonates; alkali metals such as lithium, sodium, potassium, calcium, magnesium, alkaline earths Examples include metal perchlorates, chlorates, hydrochlorides, bromates, iodates, borofluorides, sulfates, trifluoromethyl sulfates, sulfonates, and the like. These ionic conductive agents are preferably used in an amount of 0.01 to 10 parts by weight, particularly 0.05 to 5 parts by weight, based on 100 parts by weight of the resin.

  In addition, the said electrically conductive agent may be used individually by 1 type, or may be used in combination of 2 or more types, In this case, it is also possible to combine an electronic conductive agent and an ionic conductive agent.

  In addition, when the conductive agent is a transparent conductive agent such as tin oxide, titanium oxide, zinc oxide, potassium titanate, barium titanate, nickel, copper, and other metal and metal oxides, ultraviolet rays are easily transmitted and ultraviolet curing is achieved. The effect of not hindering the polymerization of the mold resin is obtained. The blending amount of the transparent conductive agent is preferably 100 parts by weight or less, particularly 1 to 80 parts by weight, particularly 10 to 50 parts by weight with respect to 100 parts by weight of the resin.

  When the resin constituting the resin layer 4 is an ultraviolet curable resin, it is preferable to contain a polymerization initiator. As the ultraviolet polymerization initiator, known ones can be used. For example, 4-dimethylaminobenzoic acid, 4-dimethylaminobenzoic acid ester, 2,2-dimethoxy-2-phenylacetophenone, acetophenone diethyl ketal, alkoxy Benzophenone derivatives such as acetophenone, benzyldimethyl ketal, benzophenone and 3,3-dimethyl-4-methoxybenzophenone, 4,4-dimethoxybenzophenone, 4,4-diaminobenzophenone, alkyl benzoylbenzoate, bis (4-dialkylaminophenyl) Benzene derivatives such as ketones, benzyl and benzylmethyl ketal, benzoin derivatives such as benzoin and benzoin isobutyl ether, benzoin isopropyl ether, 2-hydroxy-2-methyl Lupropiophenone, 1-hydroxycyclohexyl phenyl ketone, xanthone, thioxanthone and thioxanthone derivatives, fluorene, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl Pentylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1,2-benzyl-2-dimethylamino Such as -1- (morpholinophenyl) -butanone-1 and the like may be used alone or in combination of two or more.

  The blending amount of the ultraviolet polymerization initiator is preferably 0.1 to 10 parts by weight per 100 parts by weight of the (meth) acrylate oligomer.

  In the present invention, in addition to the above essential components, a tertiary amine such as triethylamine and triethanolamine, and an alkyl phosphine such as triphenylphosphine, if necessary, in order to promote the photopolymerization reaction by the photopolymerization initiator. A photopolymerization accelerator, a thioether photopolymerization accelerator such as p-thiodiglycol, and the like may be added. The amount of these compounds added is usually preferably in the range of 0.01 to 10 parts by weight per 100 parts by weight of the (meth) acrylate oligomer.

  For at least the outermost resin layer, it is preferable that the resin constituting the layer contains one or both of fluorine and silicon, thereby reducing the surface energy of the outermost resin layer. As a result, the frictional resistance of the developing roller can be reduced, the toner releasability can be improved, wear during long-term use can be reduced, and durability can be improved.

  As a raw material for forming an ultraviolet curable resin containing fluorine, it is preferable to contain a fluorine-containing compound having a polymerizable carbon-carbon double bond, and the fluorine-containing compound having a polymerizable carbon-carbon double bond. Or a composition comprising a blend of a fluorine-containing compound having a polymerizable carbon-carbon double bond and another type of polymerizable compound having a carbon-carbon double bond. Good.

  As the fluorine-containing compound having a polymerizable double bond between carbon atoms, fluoroolefins and fluoro (meth) acrylates are suitable.

As fluoroolefins, those having 2 to 12 carbon atoms in which 1 to all hydrogen atoms are substituted with fluorine are preferable. Specifically, hexafluoropropene [CF ₃ CF═CF ₂ , fluorine content 76 % By weight], (perfluorobutyl) ethylene [F (CF ₂ ) ₄ CH═CH ₂ , fluorine content 69 wt%], (perfluorohexyl) ethylene [F (CF ₂ ) ₆ CH═CH ₂ , fluorine containing 71% by weight], (perfluorooctyl) ethylene [F (CF ₂ ) ₈ CH═CH ₂ , fluorine content 72% by weight], (perfluorodecyl) ethylene [F (CF ₂ ) ₁₀ CH═CH ₂ , fluorine content 73% by weight], chlorotrifluoroethylene _[CF 2 = CFCl, fluorine content 49 wt%, 1-methoxy - (perfluoro-2 Chill-1-propene _{[(CF 3) 2 C =} CFOCH 3, fluorine content 63 wt%, 1,4-vinyl octafluorobutane _{[(CF 2) 4 (CH} = CH 2) 2, fluorine content 60 % By weight], 1,6-divinyldodecafluorohexane [(CF ₂ ) ₆ (CH═CH ₂ ) ₂ , fluorine content 64% by weight], 1,8-divinylhexadecafluorooctane [(CF ₂ ) ₈ ( CH = CH ₂ ) ₂ , fluorine content 67 wt%].

As the fluoro (meth) acrylate, a fluoroalkyl (meth) acrylate having 5 to 16 carbon atoms in which 1 to all hydrogen atoms are substituted with fluorine is preferable. Fluoroethyl acrylate (CF ₃ CH ₂ OCOCH═CH ₂ , fluorine content 34 wt%), 2,2,3,3,3-pentafluoropropyl acrylate (CF ₃ CF ₂ CH ₂ OCOCH═CH ₂ , fluorine content 44 _{wt%), F (CF 2)} 4CH 2 CH 2 OCOCH = CH 2 ( fluorine content 51 wt%), 2,2,2-trifluoroethyl acrylate _{[CF 3 CH 2 OCOCH = CH} 2, the fluorine content 37 wt%], 2,2,3,3,3-pentafluoropropyl acrylate [CF ₃ CF ₂ CH ₂ OCOCH = CH ₂ , fluorine content 47 wt%], 2- (perfluorobutyl) ethyl acrylate [F (CF ₂ ) ₄ CH ₂ CH ₂ OCOCH═CH ₂ , fluorine content 54 wt%], 3- (perfluorobutyl ) -2-hydroxypropyl acrylate [F (CF ₂ ) ₄ CH ₂ CH (OH) CH ₂ OCOCH═CH ₂ , fluorine content 49 wt%], 2- (perfluorohexyl) ethyl acrylate [F (CF ₂ ) ₆ CH ₂ CH ₂ OCOCH═CH ₂ , fluorine content 59 wt%], 3- (perfluorohexyl) -2-hydroxypropyl acrylate [F (CF ₂ ) ₆ CH ₂ CH (OH) CH ₂ OCOCH═CH ₂ , Fluorine content 55 wt%], 2- (perfluorooctyl) ethyl acrylate [F (CF ₂ ) ₈ CH ₂ CH ₂ OCOCH═CH ₂ , fluorine content 62 wt%], 3- (perfluorooctyl) -2-hydroxypropyl acrylate [F (CF ₂ ) ₈ CH ₂ CH (OH) CH ₂ OCOCH═CH ₂ , fluorine Content 59 wt%], 2- (perfluorodecyl) ethyl acrylate [F (CF ₂ ) ₁₀ CH ₂ CH ₂ OCOCH═CH ₂ , fluorine content 65 wt%], 2- (perfluoro-3-methylbutyl) Ethyl acrylate [(CF ₃ ) ₂ CF (CF ₂ ) ₂ CH ₂ CH ₂ OCOCH═CH ₂ , fluorine content 57 wt%], 3- (perfluoro-3-methylbutyl) -2-hydroxypropyl acrylate [(CF _{3) 2 CF (CF 2)} 2 CH 2 CH (OH) CH 2 OCOCH = CH 2, the fluorine content 5 Wt%], 2- (perfluoro-5-methylhexyl) ethyl acrylate _{[(CF 3) 2 CF (} CF 2) 4 CH 2 CH 2 OCOCH = CH 2, fluorine content 61 wt%], 3- (par Fluoro-5-methylhexyl) -2-hydroxypropyl acrylate [(CF ₃ ) ₂ CF (CF ₂ ) ₄ CH ₂ CH (OH) CH ₂ OCOCH═CH ₂ , fluorine content 57 wt%], 2- (par Fluoro-7-methyloctyl) ethyl acrylate [(CF ₃ ) ₂ CF (CF ₂ ) ₆ CH ₂ CH ₂ OCOCH═CH ₂ , fluorine content 64 wt], 3- (perfluoro-7-methyloctyl) -2 -Hydroxypropyl acrylate [(CF ₃ ) ₂ CF (CF ₂ ) ₆ CH ₂ CH (OH) CH ₂ OCOCH = CH ₂ , Nitrogen content 60 wt%], 1H, 1H, 3H-tetrafluoropropyl acrylate [H (CF ₂ ) ₂ CH ₂ OCOCH═CH ₂ , fluorine content 41 wt%], 1H, 1H, 5H-octafluoropentyl Acrylate [H (CF ₂ ) ₄ CH ₂ OCOCH═CH ₂ , fluorine content 53 wt%], 1H, 1H, 7H-dodecafluoroheptyl acrylate [H (CF ₂ ) ₆ CH ₂ OCOC (CH ₃ ) = CH ₂ , Fluorine content 59 wt%], 1H, 1H, 9H-hexadecafluorononyl acrylate [H (CF ₂ ) ₈ CH ₂ OCOCH═CH ₂ , fluorine content 63 wt%], 1H-1- (trifluoromethyl ) Trifluoroethyl acrylate [(CF ₃ ) ₂ CHOCOCH═CH ₂ , fluorine content 51 wt%], 1H, 1H, 3H-hexafluorobutyl acrylate [CF ₃ CHFCF ₂ CH ₂ OCOCH═CH ₂ , fluorine content 48 wt%], 2,2,2-trifluoroethyl methacrylate [CF ₃ CH ₂ OCOC (CH ₃ ) = CH _2, fluorine content 34 wt%], 2,2,3,3,3-pentafluoro-propyl methacrylate _{[CF 3 CF 2 CH 2 OCOC} (CH 3) = CH 2, fluorine content 44 wt%, 2- (perfluorobutyl) ethyl methacrylate [F (CF ₂ ) ₄ CH ₂ CH ₂ OCOC (CH ₃ ) = CH ₂ , fluorine content 51 wt%], 3- (perfluorobutyl) -2-hydroxypropyl methacrylate _{[F (CF 2) 4 CH} 2 CH (OH) CH 2 OCOC (CH 3) = CH 2, fluorine-containing Rate 47% by weight], 2- (perfluorohexyl) ethyl methacrylate _{[F (CF 2) 6 CH} 2 CH 2 OCOC (CH 3) = CH 2, fluorine content 57 wt%], 3- (perfluorohexyl) 2-hydroxypropyl methacrylate [F (CF ₂ ) ₆ CH ₂ CH (OH) CH ₂ OCOC (CH ₃ ) = CH ₂ , fluorine content 53 wt%], 2- (perfluorooctyl) ethyl methacrylate [F ( _{CF 2) 8 CH 2 CH 2} OCOC (CH 3) = CH 2, fluorine content 61 wt%, 3-perfluorooctyl-2-hydroxypropyl methacrylate _{[F (CF 2) 8 CH} 2 CH (OH) CH ₂ OCOC (CH ₃ ) = CH ₂ , fluorine content 57 wt%], 2- (perfluorodecyl) ethyl methacrylate [F (CF ₂ ) ₁₀ CH ₂ CH ₂ OCOC (CH ₃ ) = CH ₂ , fluorine content 63 wt%], 2- (perfluoro-3-methylbutyl) ethyl methacrylate [(CF ₃ ) ₂ CF ( _{CF 2) 2 CH 2 CH 2} OCOC (CH 3) = CH 2, fluorine content 55 wt%], 3- (perfluoro-3-methylbutyl) -2-hydroxypropyl methacrylate _{[(CF 3) 2 CF (} CF ₂ ) ₂ CH ₂ CH (OH) CH ₂ OCOC (CH ₃ ) = CH ₂ , fluorine content 51 wt%], 2- (perfluoro-5-methylhexyl) ethyl methacrylate [(CF ₃ ) ₂ CF (CF _{2) 4 CH 2 CH 2 OCOC} (CH 3) = CH 2, fluorine content 59 wt%], 3- (perfluoro-5-methylhexyl) -2 Hydroxypropyl methacrylate _{[(CF 3) 2 CF (} CF 2) 4 CH 2 CH (OH) CH 2 OCOC (CH 3) = CH 2, fluorine content 56 wt%], 2- (perfluoro-7-methyl-octyl ) Ethyl methacrylate [(CF ₃ ) ₂ CF (CF ₂ ) ₆ CH ₂ CH ₂ OCOC (CH ₃ ) = CH ₂ , fluorine content 62 wt%], 3- (perfluoro-7-methyloctyl) -2- hydroxypropyl methacrylate _{[(CF 3) 2 CF (} CF 2) 6 CH 2 CH (OH) CH 2 OCOC (CH 3) = CH 2, fluorine content 59 wt%], 1H, 1H, 3H- tetrafluoropropyl methacrylate _{[H (CF 2) 2 CH} 2 OCOC (CH 3) = CH 2, fluorine content 51 wt%], 1H, 1H, 5 - octafluoro pentyl methacrylate _{[H (CF 2) 4 CH} 2 OCOC (CH 3) = CH 2, fluorine content 51 wt%], 1H, 1H, 7H- dodecafluoroheptyl methacrylate _{[H (CF 2) 6 CH} 2 OCOC (CH ₃ ) = CH ₂ , fluorine content 57 wt%], 1H, 1H, 9H-hexadecafluorononyl methacrylate [H (CF ₂ ) ₈ CH ₂ OCOC (CH ₃ ) = CH ₂ , fluorine content 61 % By weight], 1H-1- (trifluoromethyl) trifluoroethyl methacrylate [(CF ₃ ) ₂ CHOCOC (CH ₃ ) = CH ₂ , fluorine content 48% by weight], 1H, 1H, 3H-hexafluorobutyl methacrylate _{[CF 3 CHFCF 2 CH 2 OCOC} (CH 3) = CH 2, the fluorine content 4 Wt%] and the like are exemplified.

  The fluorine-containing compound having a polymerizable double bond between carbon atoms is preferably a monomer, an oligomer, or a mixture of a monomer and an oligomer. As an oligomer, a 2-20 mer is preferable.

  The compound having another polymerizable double bond between carbon atoms that may be blended with the fluorine-containing compound having a double bond between carbon atoms is not particularly limited. ) Acrylate monomers or oligomers or mixtures of monomers and oligomers are preferred.

  Examples of the (meth) acrylate monomer or oligomer include, for example, urethane (meth) acrylate, epoxy (meth) acrylate, ether (meth) acrylate, ester (meth) acrylate, and polycarbonate (meth) acrylate. Or an oligomer, the monomer or oligomer of a silicone type (meth) acryl, etc. can be mentioned.

  The (meth) acrylate oligomer includes polyethylene glycol, polyoxypropylene glycol, polytetramethylene ether glycol, bisphenol A type epoxy resin, phenol novolac type epoxy resin, polyhydric alcohol and ε-caprolactone adduct, and the like ( It can be synthesized by reaction with (meth) acrylic acid or by urethanizing a polyisocyanate compound and a (meth) acrylate compound having a hydroxyl group.

  A urethane type (meth) acrylate oligomer is obtained by urethanizing a polyol, an isocyanate compound, and a (meth) acrylate compound having a hydroxyl group.

  Examples of the epoxy-based (meth) acrylate oligomer may be any reaction product of a compound having a glycidyl group and (meth) acrylic acid. Among them, a benzene ring, a naphthalene ring, a spiro ring, a dicyclopentadiene, A reaction product of a compound having a cyclic structure such as tricyclodecane and having a glycidyl group and (meth) acrylic acid is preferred.

  Furthermore, ether-based (meth) acrylate oligomers, ester-based (meth) acrylate oligomers and polycarbonate-based (meth) acrylate oligomers react with polyols (polyether polyols, polyester polyols and polycarbonate polyols) and (meth) acrylic acid, respectively. Can be obtained by:

  The raw material for forming the ultraviolet curable resin containing silicon preferably contains a silicon-containing compound having a polymerizable carbon-carbon double bond, and silicon having a polymerizable carbon-carbon double bond. The composition may be composed of only a contained compound, and is composed of a composition obtained by blending a silicon-containing compound having a polymerizable carbon-carbon double bond and another kind of polymerizable compound having a carbon-carbon double bond. May be.

  As the silicon-containing compound having a polymerizable double bond between carbon atoms, both-end-reactive silicone oils, one-end-reactive silicone oils, and (meth) acryloxyalkylsilanes are suitable. As the reactive silicone oil, those having a (meth) acryl group introduced at the terminal are preferable.

  Specific examples of the silicon-containing compound suitable for the present invention are shown below.

  One of these silicon-containing compounds may be used alone, or two or more thereof may be mixed and used, or another compound having a carbon-carbon double bond that does not contain silicon may be used.

  These silicon-containing compounds having a polymerizable carbon-carbon double bond and other compounds having no carbon-containing carbon-carbon double bond are preferably used as a monomer, an oligomer, or a mixture of a monomer and an oligomer.

  The other compound having a polymerizable double bond between carbon atoms that may be blended with the silicon-containing compound having a polymerizable double bond between carbon atoms is not particularly limited. ) Acrylate monomers or oligomers or mixtures of monomers and oligomers are preferred. As an oligomer, a 2-20 mer is preferable.

  Examples of the (meth) acrylate monomer or oligomer include urethane (meth) acrylate, epoxy (meth) acrylate, ether (meth) acrylate, ester (meth) acrylate, polycarbonate (meth) acrylate, and the like. And fluorine-based (meth) acrylic monomers or oligomers.

  The (meth) acrylate oligomer includes polyethylene glycol, polyoxypropylene glycol, polytetramethylene ether glycol, bisphenol A type epoxy resin, phenol novolac type epoxy resin, polyhydric alcohol and ε-caprolactone adduct, and the like ( It can be synthesized by reaction with (meth) acrylic acid or by urethanizing a polyisocyanate compound and a (meth) acrylate compound having a hydroxyl group.

  A urethane type (meth) acrylate oligomer is obtained by urethanizing a polyol, an isocyanate compound, and a (meth) acrylate compound having a hydroxyl group.

  Examples of the epoxy-based (meth) acrylate oligomer may be any reaction product of a compound having a glycidyl group and (meth) acrylic acid. Among them, a benzene ring, a naphthalene ring, a spiro ring, a dicyclopentadiene, A reaction product of a compound having a cyclic structure such as tricyclodecane and having a glycidyl group and (meth) acrylic acid is preferred.

  Further, ether (meth) acrylate oligomers, ester (meth) acrylate oligomers and polycarbonate (meth) acrylate oligomers react with polyols (polyether polyols, polyester polyols and polycarbonate polyols) and (meth) acrylic acid for each. Can be obtained by:

  In addition, an appropriate amount of various additives can be added to the ultraviolet curable resin constituting the resin layer 4 as necessary.

  Further, it is preferable to disperse fine particles in the resin layer 4, thereby forming minute irregularities on the surface of the resin layer 4 to ensure the conveying force of the toner carried on the outer peripheral surface to the latent image holding member. Can be a thing.

  The fine particles are preferably rubber or synthetic resin fine particles or carbon fine particles. Specifically, silicone rubber, acrylic resin, styrene resin, acrylic / styrene copolymer, fluorine resin, urethane elastomer, urethane acrylate, melamine resin. One type or two or more types of phenol resins are preferred.

  The addition amount of the fine particles is preferably 0.1 to 100 parts by weight, particularly 5 to 80 parts by weight with respect to 100 parts by weight of the resin.

  The average particle diameter a of the fine particles is preferably 1 to 50 μm, particularly 3 to 20 μm. The thickness b of the resin layer in which fine particles are dispersed is preferably 1 to 50 μm, and the ratio a / b between the average particle diameter a (μm) of the fine particles and the thickness b (μm) is 1. It is preferable to set it to 0.0 to 5.0, and by setting the a / b ratio within this range, appropriate fine irregularities can be formed on the surface of the resin layer 4.

  As a method of forming the resin layer 4 made of an ultraviolet curable resin or an electron beam curable resin, a coating liquid made of a composition containing the resin component and the conductive agent and other additives is applied to the surface. A method of irradiating with ultraviolet rays or electron beams is preferably employed. This coating solution is preferably one that does not contain a solvent, or a solvent that is highly volatile even at room temperature may be used as the solvent.

  As a method for applying the coating liquid, a dipping method in which a developing roller having no resin layer in the resin liquid is dipped in a dipping solution, a spray coating method, a roll coating method, or the like is appropriately selected according to the situation. be able to.

  The thickness of the resin layer 4 is not particularly limited, but is usually 1 to 500 μm, particularly 3 to 200 μm, and particularly preferably about 5 to 100 μm. If the thickness is less than 1 μm, the charging performance of the surface layer may not be sufficiently secured due to friction during long-term use. On the other hand, if the thickness exceeds 500 μm, the developing roller surface becomes hard and damages the toner. In some cases, the toner adheres to an image forming body such as a photoreceptor or a stratified blade, resulting in an image defect.

The volume resistivity of at least the outermost resin layer of the resin layer ⁴ is preferably 1 × 10 ⁴ to 1 × 10 ¹⁴ Ω · cm.

  Next, the elastic layer 3 will be described. Although the elastic layer 3 is not an essential component, the stress applied to the resin layer 4 when the resin layer 4 is pressed against the latent image holding member or the layered blade can be relieved, and the durability of the resin layer is improved. It is preferable to provide a semiconductive elastic layer 3 for such purposes as the elastic layer 3. As the elastic layer 3, an elastic body obtained by adding a conductive agent to an elastomer alone or a foam body obtained by foaming the elastomer is used. It is done. The elastomer that can be used here is not particularly limited, and nitrile rubber, ethylene-propylene rubber, styrene-butadiene rubber, butadiene rubber, isoprene rubber, natural rubber, silicone rubber, urethane rubber, acrylic rubber, chloroprene rubber, butyl rubber, An epichlorohydrin rubber etc. are illustrated and these can be used individually or in combination of 2 or more types. Of these, ethylene-propylene rubber, butadiene rubber, silicone rubber, and urethane rubber are preferably used in the present invention. A mixture of these and other rubber materials is also preferably used. In particular, in the present invention, a resin having a urethane bond is preferably used.

  Moreover, these elastomers can be used as foam bodies that are chemically foamed using a foaming agent, or foamed by mechanically entraining air like polyurethane foam. In the present invention, a so-called RIM molding method may be used in a molding process for integrating the shaft member 2 and the elastic layer 3. That is, two types of monomer components constituting the raw material component of the elastic layer 3 are mixed and injected into a cylindrical mold and polymerized to integrate the shaft member 2 and the elastic layer 3. As a result, the molding process can be performed in about 60 seconds from the injection of the raw material to the demolding, so that the production cost can be greatly reduced.

  As the conductive agent added to the elastic layer 3, the same conductive agent blended in the resin constituting the resin layer 4 can be used.

In the present invention, the volume resistivity of the semiconductive elastic layer is adjusted to 1 × 10 ³ to 1 × 10 ¹⁰ Ω · cm, preferably 1 × 10 ⁴ to 1 × 10 ⁸ Ω · cm.

  Since the developing roller 1 is used in contact with an image forming body, a stratified blade, or the like, the elastic layer 3 preferably has a small compression set, specifically 20% or less, and further 10% or less. It is preferable. Use of polyurethane rubber as the rubber material is preferable because the compression set can be designed to be small.

  A cross-linking agent and a vulcanizing agent can be added to the conductive elastic layer 3 as necessary in order to make the elastomer into a rubber-like substance. In this case, a vulcanization aid, a vulcanization accelerator, a vulcanization acceleration aid, a vulcanization retarder, etc. can be used in any case of organic peroxide crosslinking and sulfur crosslinking. In addition to the above, peptizers, foaming agents, plasticizers, softeners, tackifiers, tackifiers, separating agents, mold release agents, extenders, and coloring agents commonly used as rubber compounding agents. Etc. can be added.

  When the elastic layer 3 is formed using polyurethane or EPDM as a base material, various charge controls such as nigrosine, triaminophenylmethane, and cationic dyes are used for the purpose of controlling the toner charge amount on the surface when used as a developing roller, for example. Fine powders such as an agent, silicone resin, silicone rubber, and nylon can be added. In this case, the addition amount of these additives is preferably 1 to 5 parts by weight for the charge control agent and 1 to 10 parts by weight for the fine powder with respect to 100 parts by weight of the polyurethane or EPDM.

  The hardness of the elastic layer 3 is not particularly limited, but it is preferably 80 degrees or less, particularly 30 to 70 degrees in terms of Asker C hardness. In this case, if the hardness exceeds 80 degrees, the original function of the elastic layer, which relieves stress applied to the developing roller and toner, cannot be expressed, and for example, the contact area between the developing roller and the latent image holder is small. Therefore, there is a possibility that good development cannot be performed. Further, the toner is damaged, and the toner adheres to the photosensitive member or the layered blade. On the other hand, if the hardness is too low, the frictional force with the photoconductor and the layered blade increases, which may cause image defects such as jitter.

  Since the elastic layer 3 is used in contact with a photoreceptor or a layered blade, even when the hardness is set to a low hardness, it is preferable to make the compression set as small as possible, specifically 20% or less. It is preferable.

  In the present invention, the surface roughness of the elastic layer 3 is preferably 1 to 20 [mu] mRz, more preferably 1.5 to 18 [mu] mRz in terms of JIS 10-point average roughness. When the average roughness exceeds 20 μm Rz, it is necessary to form a thick coating layer of the developing roller, so that the surface of the developing roller becomes hard. As a result, the toner is damaged and the toner adheres to the image forming body or the stratified blade. May occur and cause image defects.

  On the other hand, when the average roughness is less than 1 μm Rz, when the coating layer is formed, the average roughness of the surface of the developing roller becomes too small, and the toner carrying amount decreases, so that the image density may be lowered. In the present invention, the surface roughness is measured using a surface roughness meter “Surfcom 590A” (manufactured by Tokyo Seimitsu Co., Ltd.) in a measurement length of 2.4 mm in a direction orthogonal to the axial direction and a measurement speed of 0.8. It is a value obtained by measuring 300 or more locations at 3 mm / sec and a cutoff wavelength of 0.8 mm so that there is no deviation in the roller shaft member direction and the circumferential direction.

The developing roller 1 of the present invention preferably has a volume resistivity of 10 ³ to 10 ¹⁰ Ωcm, particularly 10 ⁴ to 10 ⁸ Ωcm. In this case, if the volume resistivity is less than 10 ³ Ωcm, gradation control becomes extremely difficult, and bias leakage may occur if there is a defect in the image forming body such as a photoreceptor. On the other hand, when the volume resistivity exceeds 10 ¹⁰ Ωcm, for example, when developing toner on a latent image holding member such as a photoreceptor, the developing bias causes a voltage drop due to the high resistance of the developing roller itself, which is sufficient for development. A developing bias cannot be secured, and a sufficient image density cannot be obtained. The resistance value is measured by, for example, pressing the outer peripheral surface of the developing roller against a flat plate or cylindrical counter electrode with a predetermined pressure, applying a voltage of 100 V between the shaft member 2 and the counter electrode, and the current value at that time. Can be obtained from

  As described above, it is important to appropriately and uniformly control the resistance value of the developing roller 1 in order to keep the electric field strength for moving the toner appropriately and uniformly.

  The developing roller 1 of the present invention can be incorporated in an image forming apparatus using toner. Specifically, as shown in FIG. 1, a toner supplying roller 94 for supplying toner and an electrostatic latent image are held. A developing roller 91 is disposed between the photosensitive drum 95 (latent image holding member) 95 with a small gap 92 with respect to the photosensitive drum 95, and the developing roller 91, the photosensitive drum 95, and the toner supply roller 94. The toner 96 is supplied to the surface of the developing roller 91 by the toner supply roller 94 by applying a predetermined voltage between the photosensitive drum 95 and the developing roller 91. A uniform thin layer can be prepared by the blade 97, and the toner 96 formed in the thin layer can fly over the gap 92 to the photosensitive drum 95 to visualize the latent image. Note that the details of FIG. 1 have been described in the background art, and will not be described.

EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not limited to these.
When the developing roller does not have an elastic layer, a resin layer is formed directly on the shaft member made of an aluminum pipe, or when the developing roller has an elastic layer, an elastic layer is formed on the shaft member. After that, the first and second resin layers are formed in this order, and the developing roller having the structure shown in FIG. 3 is produced. Examples 1 to 9 are used, and for comparison with the developing roller of the example, a resin is used. A developing roller having a part of the configuration different from that of the present invention including a developing roller having only a shaft member not having a layer was prepared as Comparative Examples 1 to 3. Then, for the developing rollers of these examples and comparative examples, measurement and evaluation of roller characteristics and image evaluation were performed. Tables 6 to 8 show the specifications of each developing roller and the results of their evaluation.

In forming each resin layer, the materials shown in Table 6 were blended in parts by weight shown in “Formulation (parts by weight)” in Tables 7 and 8, and the shaft member was placed in a solution in which the blended resin material was dissolved. Immersion coating (dip method) or a coating made of the compounded resin material was applied with a roll coater (coater method), and then this was heat-cured (heated or air-dried), UV-cured, or electron-beam cured. .
Regarding the preparation of each sample, whether the resin was applied by the dip method or the coater method, and whether the curing process was performed by heat curing (heating or air drying), ultraviolet curing, or electron beam curing Are listed in the corresponding columns of Tables 7 and 8.
In order to cure the resin layer with ultraviolet rays, the UV light is irradiated at an illuminance of 400 mW and an integrated light quantity of 1000 mJ / cm ² using a UNICURE UVH-0252C apparatus manufactured by USHIO ELECTRIC CO., LTD. While rotating the developing roller coated with the resin layer. Was irradiated. Further, when the resin is cured by an electron beam, a roller 30 is rotated using a Min-EB apparatus manufactured by Ushio Electric Co., Ltd., a pressurizing voltage 30 kV, a tube current 300 μA, an irradiation distance 100 mm, a nitrogen atmosphere 760 mmTorr, irradiation Electron beam irradiation was performed for 1 minute.

  The presence / absence of the elastic layer and the material of the elastic layer when the elastic layer is formed are described in the column “Presence / absence / type of elastic layer”.

  When the elastic layer is made of urethane, propylene oxide and ethylene oxide are added to glycerin to obtain a molecular weight of 5000, and 100 parts by weight of a polyether polyol (OH value 33). Add 0 parts by weight, 1.5 parts by weight of silicone surfactant, 0.5 parts by weight of nickel acetylacetonate, 0.01 parts by weight of dibutyltin dilaurate and 0.01 parts by weight of sodium perchlorate and mix with a mixer. Thus, a polyol composition was prepared. After the polyol composition was stirred and degassed under reduced pressure, 17.5 parts by weight of urethane-modified MDI was added and stirred for 2 minutes, and then the shaft member was placed in and heated to 110 ° C. It was cast into a mold or a container and cured for 2 hours, and the outer periphery was polished to form an elastic layer having an outer diameter of 12 mm, an elastic layer thickness of 500 μm, and a total length of 210 mm.

  When the elastic layer is made of silicone, liquid silicone rubber is injected into the cavity of the mold in which the shaft member is inserted, and is cooled and cured in the mold. An elastic layer having a layer portion thickness of 300 μm and a total length of 210 mm was formed.

  The toner charge amount and toner transport amount in Tables 7 and 8 were determined as follows. That is, a cartridge equipped with a developing roller is incorporated into the image forming apparatus, the developing roller is idled without printing, the cartridge is taken out, and the toner charge amount is measured by taking the toner on the surface of the developing roller into the Faraday gauge. Further, when the toner charge amount is measured as described above, the weight of the removed toner is measured, and the area of the developing roller surface portion from which the toner has been removed is calculated, whereby the toner weight per unit area is calculated. The obtained toner transport amount was used.

  The image evaluation was performed as follows. That is, the development roller of each example and comparative example is mounted on a commercially available printer having a nonmagnetic jumping development unit portion shown in FIG. 1, and a development bias voltage in which alternating current is superimposed on direct current is applied, Reverse jumping development was performed using a negatively charged nonmagnetic one-component toner having an average particle diameter of 7 μm. “Initial” image evaluation is performed by printing a black image, a full white image, a halftone image, and a pattern image immediately after mounting the developing roller, and visually determining the print image quality for each evaluation item in the table. Judgment results were expressed in a five-step evaluation.

  In the five-level evaluation, 5 is “particularly good”, 4 is “good”, 3 is “pass level”, 2 is “slightly bad”, 1 is “NG”, and 3 or more are passed as products. It is a possible level.

  In addition, the environment is changed from low temperature and low humidity (15 ° C x 10%) to high temperature and high humidity (32 ° C x 85%), and in the same way, the judgment is based on the five-level evaluation of printed images (the larger the number, the less the influence of the environment). The results are shown in the “Environmental impact” column.

  Further, the image evaluation of “after endurance of 10,000 sheets” was evaluated in the same manner as “initial stage” after continuously printing 10,000 images of 5% printing density.

  As is clear from Tables 7 and 8, it can be seen that good image evaluation results can be obtained with any of the developing roller samples of the examples.

  The developing roller according to the present invention includes a charging roller, a developing roller, a transfer roller, a paper feeding roller, a toner in an image forming apparatus such as a plain paper copying machine, a plain paper facsimile machine, a laser beam printer, a color laser beam printer, and a toner jet printer. It is preferably used as a supply roller.

It is a conceptual diagram which shows the image forming apparatus used for a nonmagnetic jumping image development method. It is sectional drawing which shows the conventional developing roller. It is sectional drawing and the side view which show the developing roller of embodiment which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Developing roller 2 Shaft member 3 Elastic layer 4 Resin layer 5 Metal pipe 5a Convex part of metal pipe 6 Shaft cap 6a Shaft part 6b Concave part of cap with shaft

Claims (9)

In a developing roller that supplies one or more resin layers on the outer side in the radial direction of a shaft member that is axially supported at both ends in the length direction and supplies a nonmagnetic developer carried on the outer peripheral surface to a latent image carrier ,
Together shall the shaft member made of a metal pipe, for the roller outer peripheral surface, the universal hardness at measurement conditions 100mN / mm ^2/60 seconds, at a position inward by 5μm from the outer peripheral surface 3N / mm ² or less A developing roller. The developing roller according to claim 1, wherein the universal hardness with respect to the outer peripheral surface is 0.1 to 3 N / mm ² .   The developing roller according to claim 1, wherein an elastic layer is disposed between the roller main body and the innermost resin layer.   4. The developing roller according to claim 3, wherein the elastic layer contains ethylene-propylene rubber, butadiene rubber, silicone rubber, urethane rubber or a mixture of these and other rubber materials.   The developing roller according to claim 3, wherein the elastic layer contains a resin having a urethane bond.   The developing roller according to claim 1, wherein at least one resin layer is made of an ultraviolet curable resin or an electron beam curable resin containing a conductive agent.   The developing roller according to claim 1, wherein at least one resin layer is formed by applying a solventless coating liquid and irradiating with ultraviolet rays or electron beams.   The developing roller according to claim 1, wherein the total thickness of the resin layer is 1 to 500 μm.   An image forming apparatus comprising the developing roller according to claim 1.

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