JP7188993B2 - Developing roller and image forming apparatus - Google Patents

Description

The present invention relates to a developing roller and an image forming apparatus.

Conventionally, in electrophotographic image forming apparatuses such as copiers, printers, and facsimiles, first, the surface of a photoreceptor is uniformly charged, an image is projected onto the photoreceptor from an optical system, and the image is exposed to light. An electrostatic latent image is obtained by an electrostatic latent image process in which a latent image is formed by erasing the charge on the portion where the electrostatic latent image is formed. , the method of printing is adopted.

FIG. 1 shows a configuration example of an image forming apparatus. In the illustrated image forming apparatus, a developing roller 10 is arranged between a toner supply roller 11 for supplying toner and a photosensitive drum (photoreceptor) 12 holding an electrostatic latent image. The toner 13 is supplied to the surface of the developing roller 10 by the toner supply roller 11 by rotating the photosensitive drum 12 and the toner supply roller 11 in the directions of the arrows in FIG. The supplied toner is formed into a uniform thin layer by the layering blade 14 . In this state, the developing roller 10 rotates with the photosensitive drum 12 . Attached to the image, the latent image is made visible.
A latent image is formed by charging the surface of the photosensitive drum 12 with the charging roller 15 and exposing image information to the charged surface with the exposure device 16 . Reference numeral 17 in the figure denotes a transfer section, where the toner image is transferred onto a recording medium 18 such as paper. A reference numeral 19 denotes a cleaning portion, and a cleaning blade 20 removes toner remaining on the surface of the photosensitive drum 12 after transfer.

JP 2011-65188 A

Here, in order to improve the image quality on a recording medium such as paper, for example, urethane particles having an average particle size of about 4 to 10 μm are contained in the surface layer of the developing roller, and the toner is carried by the particles. Then, the toner mass (M/A) per unit area of the surface of the developing roller (hereinafter also simply referred to as toner mass) is adjusted to a predetermined amount. However, from the viewpoint of improving image quality, it is important to adjust not only the toner mass but also the charge amount per toner unit mass (Q/M) (hereinafter simply referred to as the toner charge amount). In (for example, Patent Document 1), when trying to adjust the toner charge amount (Q/M), it becomes difficult to adjust the toner mass (M/A), and it was not possible to sufficiently and appropriately adjust each of them (for example, When the toner charge amount (Q/M) of the positively charged toner is reduced, the toner mass (M/A) becomes too high). There is also a method of using an ionic liquid as a method of controlling the toner charge amount (Q/M), but there is a concern that such a method may contaminate the toner.

Accordingly, the present invention provides a developing roller capable of appropriately adjusting the amount of charge per unit mass of toner (Q/M) and the mass of toner per unit area of the developing roller (M/A), and image quality. It is an object of the present invention to provide an image forming apparatus that can be improved.

A developing roller of the present invention is a developing roller comprising a shaft member, a base layer positioned radially outward of the shaft member, and a surface layer positioned radially outward of the base layer and forming a surface,
The surface layer contains triazine-based resin particles having an average particle size of 2 μm or less,
The value obtained by dividing the content (parts by mass) of the triazine-based resin particles with respect to 100 parts by mass of the binder resin contained in the surface layer by the average particle size (μm) of the triazine-based resin particles is 38 to 750. Characterized by
According to the developing roller of the present invention, the toner charge amount (Q/M) and the toner mass (M/A) can be properly adjusted.

In the developing roller of the present invention, the value obtained by dividing the content (parts by mass) of the triazine-based resin particles with respect to 100 parts by mass of the binder resin contained in the surface layer by the average particle diameter (μm) of the triazine-based resin particles is It is preferably 150-750, more preferably 350-750. According to this configuration, the toner charge amount (Q/M) and the toner mass (M/A) can be adjusted more appropriately.

In the developing roller of the present invention, the triazine-based resin particles preferably have an average particle size of 1 μm or less. With this configuration, an increase in toner mass (M/A) can be suppressed.

An image forming apparatus of the present invention includes the developing roller described above. According to the image forming apparatus of the present invention, image quality can be improved.

According to the present invention, a developing roller capable of appropriately adjusting the amount of charge per unit mass of toner (Q/M) and the mass of toner per unit area (M/A), and improving image quality. It is possible to provide an image forming apparatus capable of

1 is a schematic diagram showing a configuration example of an image forming apparatus; FIG. 1 is a cross-sectional view showing a developing roller according to one embodiment of the present invention in cross section along the axial direction; FIG.

An embodiment of the present invention will be exemplified below with reference to the drawings.
The developing roller of this embodiment can be used in an image forming apparatus (for example, a laser printer) as shown in FIG. 1. As shown in the axial cross-sectional view of FIG. A base layer 3 positioned radially outside the shaft member 2 and a surface layer 4 positioned radially outside the base layer 3 and forming the surface of the developing roller 1 are provided. Further, the surface layer 4 of the developing roller 1 of the present embodiment contains triazine-based resin particles having an average particle size of 2 μm or less, and the content (parts by mass) of the triazine-based resin particles with respect to 100 parts by mass of the binder resin contained in the surface layer 4 is , the value obtained by dividing by the average particle size (μm) of the triazine-based resin particles is 38-750.
In the developing roller 1 of the present embodiment, the layers formed on the shaft member 2 are not limited to the base layer 3 and the surface layer 4. Optionally, a single layer or multiple other layers may be formed in between. For example, a plurality of layers may be provided between the base layer 3 and the surface layer 4 in order to develop roller characteristics such as adhesiveness and electrical resistance adjustment.

In the example shown in FIG. 2, the shaft member 2 is rod-shaped with a substantially constant outer diameter from one axial end to the other axial end of the shaft member 2 . However, the shaft member 2 is not limited to the illustrated example. For example, a hollow cylindrical pipe and a pair of caps with shafts attached to both ends of the pipe and having shafts serving as both ends of the shaft member 2 in the axial direction. , can also be a hollow body.

The shaft member 2 can be made of a metal material, and the metal material is not particularly limited, and examples thereof include iron, stainless steel, aluminum, and alloys containing these. Alternatively, the shaft member 2 may be made of a highly rigid resin material containing a conductive agent.
Further, the outer diameter of the shaft member 2 can be 3 to 8 mm from the viewpoint of weight reduction while providing sufficient strength.

The base layer 3 is located radially outside the shaft member 2 and can be a layer having electrical conductivity and elasticity. Specifically, the base layer 3 can be formed of a known rubber or resin, or a foam body in which cells are dispersed therein. Specifically, materials for forming the base layer 3 include polyurethane resins (including acrylate polymers having multiple urethane skeletons), silicone rubbers, butadiene rubbers, isoprene rubbers, chloroprene rubbers, styrene-butadiene rubbers, and ethylene-propylene rubbers. Rubber compositions using rubber, polynorbornene rubber, styrene-butadiene-styrene rubber, epichlorohydrin rubber, etc. as base rubbers are exemplified, and polyurethane resins are particularly preferred. The expansion ratio of the foam is not particularly limited, but is preferably 1.2 to 50 times, more preferably 1.5 to 10 times. A suitable foam density is 0.1 to 0.7 g/cm ³ .

The base layer 3 can contain a conductive agent such as an ionic conductive agent or an electronic conductive agent in order to provide conductivity. The conductive agent is not limited, but examples of ion conductive agents include tetraethylammonium, tetrabutylammonium, dodecyltrimethylammonium (e.g., lauryltrimethylammonium), hexadecyltrimethylammonium, octadecyltrimethylammonium (e.g., stearyltrimethylammonium), benzyltrimethylammonium, modified fatty acid dimethylethylammonium, etc., and ammonium with perchloric acid, chloric acid, hydrochloric acid, bromic acid, iodic acid, hydroboric acid, sulfuric acid, ethylsulfuric acid, carboxylic acid, sulfonic acid, etc. Salts; alkali metals and alkaline earth metals such as lithium, sodium, potassium, calcium, and magnesium with perchloric acid, chloric acid, hydrochloric acid, bromic acid, iodic acid, hydroboric acid, trifluoromethylsulfuric acid, sulfonic acid, etc. alkali metal salts or alkaline earth metal salts of; Examples of electronic conductive agents include conductive carbons such as ketjen black and acetylene black; rubber carbons such as SAF, ISAF, HAF, FEF, GPF, SRF, FT, and MT; carbon, pyrolytic carbon, natural graphite, artificial graphite; conductive metal oxides such as tin oxide, titanium oxide and zinc oxide; and metals such as nickel, copper, silver and germanium. These conductive agents may be used alone or in combination of two or more.

The base layer 3 is not particularly limited, but preferably has a volume resistivity of 10 ³ to 10 ¹⁰ Ωcm, more preferably 10 ⁴ to 10 ⁸ Ωcm, from the viewpoint of obtaining good image quality. Good image quality can be obtained by setting the volume resistivity within the above range.

In addition to the above conductive agent, the base layer 3 may optionally contain a foaming agent, a foam stabilizer, a curing agent, a thickener, an antifoaming agent, a leveling agent, a dispersant, a thixotropic agent, and a blocking agent. Appropriate amounts of known additives such as inhibitors, cross-linking agents, and film-forming aids can be added.
Furthermore, the base layer 3 is not particularly limited, but can be formed, for example, by coating the surface of the shaft member 2 with a paint of a resin composition that is a raw material of the base layer 3. Examples of the coating method include a die coating method and a roll coating method. A coating method, a dipping method, a spray method, a comma coating method, or the like can be used.

The thickness of the base layer 3 is preferably 0.2 to 5 mm, more preferably 0.5 to 5 mm. By setting the thickness of the base layer 3 within such a range, the flexibility can be improved and the weight can be reduced.

The surface layer 4 is positioned radially outside the base layer 3 and forms the surface of the developing roller 1 . The surface layer 4 is formed of a binder resin, which will be described later, and a resin composition containing triazine resin particles having an average particle size of 2 μm or less. ) divided by the average particle size (μm) of the triazine-based resin particles is 38-750.
Thus, the surface layer 4 contains triazine-based resin particles having an average particle diameter of 2 μm or less so that the content and the average particle diameter satisfy a predetermined relationship, whereby the toner charge amount (Q/M) and The toner mass (M/A) can be properly adjusted.
Specifically, when a positively charged toner is used, if the toner mass (M/A) of the developing roller becomes too high, the toner may be transported excessively, resulting in poor printing or contamination of the photoreceptor. Also, if the toner charge amount (Q/M) is too high, the transfer of the toner from the developing roller 1 to the photoreceptor is not performed smoothly, and a predetermined print density may not be obtained. Further, in the case of negatively charged toner, if the toner charge amount (Q/M) becomes too small, it may be impossible to obtain a predetermined print density. Therefore, from the viewpoint of improving image quality on a recording medium, it is required to appropriately adjust the toner charge amount (Q/M) and the toner mass (M/A).
In the conventional developing roller, when positively charged toner is used, the toner charge amount (Q/M) should be adjusted so as to be small without increasing the toner mass (M/A) of the developing roller too much. (Conversely, in the case of negatively charged toner, it was difficult to adjust the toner charge amount (Q/M) to a high level without increasing the toner mass (M/A) too much. (The following description focuses on positively charging toner). Specifically, in the conventional developing roller, the toner mass (M/A) of the developing roller is set to a predetermined amount. is likely to be charged, and the toner charge amount (Q/M) becomes too large. As a result, a large amount of toner was carried on the particles, and the toner mass (M/A) became too large.
In contrast, in the developing roller 1 of the present embodiment, the surface layer 4 contains triazine-based resin particles having an average particle size of 2 μm or less, thereby preventing the developing roller 1 from carrying too much toner (that is, While avoiding an increase in the toner mass (M/A), the toner charge amount (Q/M) can be easily reduced by the triazine-based resin particles, which tend to be positively charged. Further, in the present embodiment, since the content of the triazine-based resin particles and the average particle diameter satisfy a predetermined relationship, the toner and the triazine-based resin particles on the surface of the surface layer 4 are likely to contact and rub each other (electrical series From the viewpoint of (2), it becomes difficult to charge positively charged toner), and the toner charge amount (Q/M) can be effectively reduced. Therefore, the toner charge amount (Q/M) and the toner mass (M/A) can be properly adjusted.
The developing roller of the present invention can be used not only for positively charged toner but also for negatively charged toner.

The triazine-based resin used for the triazine-based resin particles is not limited as long as it has a triazine skeleton. - Formaldehyde co-condensation resin, melamine/benzoguanamine/formaldehyde co-condensation resin, benzoguanamine/formaldehyde condensate, etc. can also be used. By using such particles, it is possible to easily reduce the toner charge amount (Q/M) while avoiding an increase in the toner mass (M/A). The triazine-based resin particles can be composed of a triazine-based resin, and the triazine-based resin particles contain other compounds (for example, silica, etc.) to the extent that the effects of the invention due to the triazine-based resin particles are not impaired. is allowed.

In the present embodiment, the triazine-based resin particles have an average particle size of 2 μm or less, more preferably 1 μm or less. By setting the average particle size to 2 μm or less, the toner mass (M/A) can be further reduced. Also, by setting the average particle diameter to 1 μm or less, an increase in toner mass (M/A) can be suppressed.
The average particle size means the volume average particle size (Mv) determined by the laser diffraction/scattering method.

In the present embodiment, the value obtained by dividing the content (parts by mass) of the triazine-based resin particles with respect to 100 parts by mass of the binder resin contained in the surface layer 4 by the average particle diameter (μm) of the triazine-based resin particles is 38 to 750. Yes, more preferably 150-750, still more preferably 350-750.
By setting the value obtained by dividing the content (parts by mass) of the triazine-based resin particles by the average particle size (μm) to 38 or more, the toner and the triazine-based resin particles on the surface of the surface layer 4 are easily contacted and rubbed (toner is difficult to charge), and the toner charge amount (Q/M) of the positively charged toner can be effectively reduced. Further, by setting the value obtained by dividing the content (parts by mass) of the triazine-based resin particles by the average particle size (μm) to 750 or less, the triazine-based resin particles are suppressed from becoming too large, and the surface layer 4 is formed. It is possible to improve the storage stability of the binder resin (the state of the paint before curing) for curing, and to improve the durability of the surface layer 4 by preventing the triazine resin particles from falling off.

The content of the triazine-based resin particles is preferably 1 to 200 parts by mass, more preferably 5 to 120 parts by mass with respect to 100 parts by mass of the binder resin of the surface layer 4 . By setting the above range, the toner charge amount (Q/M) and the toner mass (M/A) can be easily adjusted.

By the way, the binder resin for the surface layer 4 is not particularly limited, and can be appropriately selected from commonly used resin materials as desired. Specific examples include urethane resins, acrylic resins, acrylic urethane resins, phenol resins, polyamide resins, polyester resins, polyether resins, epoxy resins, amino resins, alkyd resins, melamine resins, and silicone resins. Also, a photocurable resin such as an ultraviolet curable resin that is cured by ultraviolet (UV) irradiation or the like can be suitably used. When a photo-curing resin is used, a long drying process is not required, so it is excellent in terms of productivity and cost. Such an ultraviolet curable resin can be composed of, for example, (A) a (meth)acrylate oligomer, (B) a (meth)acrylate monomer, and (C) a photopolymerization initiator.

(A) The (meth)acrylate oligomer is an oligomer having one or more acryloyloxy groups (CH ₂ =CHCOO-) or methacryloyloxy groups (CH ₂ =C(CH ₃ )COO-). Specific examples of (meth)acrylate oligomers include urethane-based (meth)acrylate oligomers, epoxy-based (meth)acrylate oligomers, ether-based (meth)acrylate oligomers, ester-based (meth)acrylate oligomers, and polycarbonate-based (meth)acrylate oligomers). Acrylate oligomers, fluorine-based (meth)acrylate oligomers, silicone-based (meth)acrylate oligomers, and the like can be mentioned, and among these, urethane-based (meth)acrylate oligomers are preferred. Such (meth)acrylate oligomers include polyethylene glycol, polyoxypropylene glycol, polytetramethylene ether glycol, bisphenol A type epoxy resin, phenol novolac type epoxy resin, adduct of polyhydric alcohol and ε-caprolactone, and the like, and (meth) It can be synthesized by reacting with acrylic acid or by urethanizing a polyisocyanate compound and a (meth)acrylate compound having a hydroxyl group. In addition, a (meth)acrylate oligomer may be used individually by 1 type, and may be used in combination of 2 or more type.

A urethane-based (meth)acrylate oligomer can be obtained by urethanizing a polyol, an isocyanate compound, and a (meth)acrylate compound having a hydroxyl group. As the epoxy-based (meth)acrylate oligomer, a reaction product of a compound having a glycidyl group and (meth)acrylic acid is preferable, and a cyclic such as a benzene ring, a naphthalene ring, a spiro ring, dicyclopentadiene, or tricyclodecane. A reaction product of a compound having a structure and having a glycidyl group and (meth)acrylic acid is more preferable. Furthermore, ether-based (meth)acrylate oligomers, ester-based (meth)acrylate oligomers, and polycarbonate-based (meth)acrylate oligomers are polyols (polyether polyols, polyester polyols, and polycarbonate polyols) for each, and (meth)acrylic acid. obtained by reaction.

The (meth)acrylate oligomer is not particularly limited, but preferably has a weight average molecular weight of 500 or more, more preferably 1000 or more. Moreover, the weight average molecular weight is preferably 40,000 or less. Here, when the weight average molecular weight is 500 or more, elongation properties can be imparted to the coating film before curing for forming the surface layer 4, and the durability of the developing roller is improved. On the other hand, if the weight-average molecular weight exceeds 40,000, the adhesiveness of the coating film increases, and workability may deteriorate.

The (meth)acrylate oligomer is not particularly limited, but preferably has 2 to 4 functional groups, more preferably 2 to 3 functional groups. Here, the functional group refers to an acryloyloxy group and a methacryloyloxy group, and the number of functional groups refers to the average number of functional groups. If the number of functional groups of the (meth)acrylate oligomer is within the above specific range, the crosslink density of the UV-curable resin is lowered, and the elastic modulus thereof can be reduced. In addition, when the number of functional groups of the (meth)acrylate oligomer is less than 2, not only the reaction rate is lowered, but also the number of reaction sites is reduced, resulting in an increase in unreacted substances and contaminants on adjacent members such as photoreceptors. Adhesion may occur. On the other hand, when the number of functional groups of the (meth)acrylate oligomer exceeds 4, not only the hardness becomes too high, but also the surface layer 4 becomes brittle, and there is a possibility that the surface layer 4 may be scraped off.

The (B) (meth)acrylate monomer is a monomer having one or more acryloyloxy groups (CH ₂ ═CHCOO—) or methacryloyloxy groups (CH ₂ ═C(CH ₃ )COO—). It acts as an agent, that is, it cures with UV light, and it is possible to reduce the viscosity of the raw material for forming the surface layer. Although the molecular weight of the (meth)acrylate monomer is not particularly limited, it is preferably from 70 to 2,000.

The (meth)acrylate monomer preferably has 1 to 4 functional groups. Here, the functional group refers to an acryloyloxy group and a methacryloyloxy group, and the number of functional groups refers to the average number of functional groups. When the number of functional groups of the (meth)acrylate monomer exceeds 4, the crosslink density in the UV-curable resin increases, which may increase the elastic modulus.

The (meth)acrylate monomer preferably has an acryloyloxy group or a methacryloyloxy group, as well as a bulky substituent or a polar group. When the (meth)acrylate monomer has a bulky substituent or polar group, the polymer chain after polymerization becomes sterically bulky, or the polar group interaction within the polymer chain becomes strong. Crystallinity is reduced. In general, amorphous polymers tend to have better elongation properties than crystalline polymers. It is considered to be effective for Suitable examples of such (meth)acrylate monomers include acryloylmorpholine, N,N-diethylaminoethyl methacrylate, isobornyl acrylate, and phenoxyethyl acrylate. The (meth)acrylate monomers may be used singly or in combination of two or more.

The (meth)acrylate monomer can also contain silicon or fluorine in the molecule. By having silicon or fluorine in the molecule of the (meth)acrylate monomer, the flexibility of the resin can be increased without increasing the coefficient of friction of the surface of the UV-curable resin. This is considered to be due to the water repellency and oil repellency of silicon or fluorine. Thereby, the elastic modulus of the ultraviolet curable resin can be reduced.

Preferred silicon-containing (meth)acrylate monomers include both-terminal reactive silicone oils, single-terminal reactive silicone oils, and (meth)acryloxyalkylsilanes. Here, both-terminal reactive silicone oils and single-terminal reactive silicone oils refer to those in which an acryloyloxy group or a methacryloyloxy group is introduced as a reactive terminal to the terminal.

（式中、ｍは繰り返し単位数である）で表されるシリコーンオイルが挙げられる。かかる両末端反応性シリコーンオイル類としては、市販品を使用することができ、例えば、信越化学工業（株）製の品名「Ｘ－２２－１６４Ａ」（粘度２５ｍｍ²／ｓ、官能基当量８６０ｇ／ｍｏｌ）、品名「Ｘ－２２－１６４Ｂ」（粘度５５ｍｍ²／ｓ、官能基当量１６３０ｇ／ｍｏｌ）、品名「Ｘ－２２－１６４Ｃ」（粘度９０ｍｍ²／ｓ、官能基当量２３７０ｇ／ｍｏｌ）、東レ・ダウコーニング・シリコーン（株）製の品番「ＢＸ１６－１５２Ｂ」（粘度４０ｃｓ／２５℃、メタクリル基当量１３００ｇ／ｍｏｌ、２５℃での比重０．９７）、品番「ＢＹ１６－１５２」（粘度８５ｃｓ／２５℃、メタクリル基当量２８００ｇ／ｍｏｌ、２５℃での比重０．９７）、品番「ＢＸ２－１５２Ｃ」（粘度３３０ｃｓ／２５℃、メタクリル基当量５１００ｇ／ｍｏｌ、２５℃での比重０．９７）等を用いることができる。 Examples of the both-end-reactive silicone oils include the following formula (I),

(In the formula, m is the number of repeating units). As such ^both -end reactive silicone oils, commercially available products can be used. mol), product name “X-22-164B” (viscosity 55 mm ² /s, functional group equivalent weight 1630 g/mol), product name “X-22-164C” (viscosity 90 mm ² /s, functional group equivalent weight 2370 g/mol), Toray・ Dow Corning Silicone Co., Ltd. product number “BX16-152B” (viscosity 40 cs / 25 ° C., methacrylic group equivalent 1300 g / mol, specific gravity at 25 ° C. 0.97), product number “BY16-152” (viscosity 85 cs / 25°C, methacrylic group equivalent 2800 g/mol, specific gravity at 25°C 0.97), product number "BX2-152C" (viscosity 330 cs/25°C, methacrylic group equivalent 5100 g/mol, specific gravity at 25°C 0.97), etc. can be used.

（式中、Ｒ¹は、メチル基またはブチル基であり、ｎは繰り返し単位数である）で表されるシリコーンオイル、および、下記式（ＩＩＩ）、

で表されるシリコーンオイルが挙げられる。かかる片末端反応性シリコーンオイル類としては、市販品を使用することができ、例えば、信越化学工業（株）製の品名「Ｘ－２４－８２０１」（粘度２５ｍｍ²／ｓ、官能基当量２１００ｇ／ｍｏｌ）、品名「Ｘ－２２－１７４ＤＸ」（粘度６０ｍｍ²／ｓ、官能基当量４６００ｇ／ｍｏｌ）、品名「Ｘ－２２－２４２６」（粘度１８０ｍｍ²／ｓ、官能基当量１２０００ｇ／ｍｏｌ）、東レ・ダウコーニング・シリコーン（株）製の品番「ＢＸ１６－１２２Ａ」（粘度５ｃｓ／２５℃、屈折率１．４１７、２５℃での比重０．９２）等を用いることができる。 Further, as the one-end reactive silicone oil, the following formula (II),

(Wherein, R ¹ is a methyl group or a butyl group, n is the number of repeating units) and a silicone oil represented by the following formula (III),

The silicone oil represented by is mentioned. As such one ^- end reactive silicone oils, commercially available products can be used. mol), product name “X-22-174DX” (viscosity 60 mm ² /s, functional group equivalent weight 4600 g/mol), product name “X-22-2426” (viscosity 180 mm ² /s, functional group equivalent weight 12000 g/mol), Toray · Product number “BX16-122A” manufactured by Dow Corning Silicone Co., Ltd. (viscosity 5 cs/25° C., refractive index 1.417, specific gravity at 25° C. 0.92) and the like can be used.

Furthermore, the above (meth)acryloxyalkylsilanes include 3-methacryloxypropyldichloromethylsilane [CH ₂ ═C(CH ₃ )COO(CH ₂ ) ₃ SiCl ₂ CH ₃ ], 3-acryloxypropyldimethoxymethyl silane [CH ₂ ═CHCOO(CH ₂ ) ₃ Si(OCH ₃ ) ₂ CH ₃ ], 3-acryloxypropyltrimethoxysilane [CH ₂ ═CHCOO(CH ₂ ) ₃ Si(OCH ₃ ) ₃ ], 3-methacrylic oxypropyldimethoxymethylsilane [CH ₂ ═C(CH ₃ )COO(CH ₂ ) ₃ Si(OCH ₃ ) ₂ CH ₃ ], 3-methacryloxypropyltrimethoxysilane [CH ₂ ═C(CH ₃ )COO(CH ₂ ) 3Si(OCH3) ₃ ], 3-methacryloxypropyldiethoxymethylsilane [CH2=C( _CH3 )COO( _CH2 )3Si( _OC2H5 ) _2CH3 ], ₃ -methacryloxypropyldiethoxymethylsilane [ _CH2 =C( _CH3 )COO( _CH2 )3Si( _OC2H5 ) _2CH3 ] roxypropyltriethoxysilane [ _CH2 =C( _CH3 )COO( _CH2 ) _{3Si(OC2H5)3 ] and the} like. As the (meth)acryloxyalkylsilanes, commercially available products can be used. LS-3375”, “LS-3380”, “LS-4548”, “LS-5118” and the like can be used.

On the other hand, the fluorine-containing (meth)acrylate monomer is preferably an alkyl (meth)acrylate having 5 to 16 carbon atoms in which one or more hydrogen atoms are substituted with fluorine. - trifluoroethyl acrylate [CF ₃ CH ₂ OCOCH=CH ₂ , fluorine content 37 mass %], 2,2,3,3,3-pentafluoropropyl acrylate [CF ₃ CF ₂ CH ₂ OCOCH=CH ₂ , fluorine content 47% by mass], 2-(perfluorobutyl)ethyl acrylate [CF ₃ (CF ₂ ) ₃ CH ₂ CH ₂ OCOCH=CH ₂ , fluorine content 54% by mass], 3-(perfluorobutyl)-2 - hydroxypropyl acrylate [CF ₃ (CF ₂ ) ₃ CH ₂ CH(OH)CH ₂ OCOCH=CH ₂ , fluorine content 49% by mass], 2-(perfluorohexyl) ethyl acrylate [CF ₃ (CF ₂ ) ₅ CH ₂ CH ₂ OCOCH=CH ₂ , fluorine content 59 mass %], 3-(perfluorohexyl)-2-hydroxypropyl acrylate [CF ₃ (CF ₂ ) ₅ CH ₂ CH(OH)CH ₂ OCOCH=CH ₂ , fluorine content 55% by mass], 2-(perfluorooctyl)ethyl acrylate [CF ₃ (CF ₂ ) ₇ CH ₂ CH ₂ OCOCH=CH ₂ , fluorine content 62% by mass], 3-(perfluorooctyl) -2-hydroxypropyl acrylate [CF ₃ (CF ₂ ) ₇ CH ₂ CH(OH)CH ₂ OCOCH=CH ₂ , fluorine content 59% by mass], 2-(perfluorodecyl)ethyl acrylate [CF ₃ (CF ₂ ) ₉ CH ₂ CH ₂ OCOCH=CH ₂ , fluorine content 65% by mass], 2-(perfluoro-3-methylbutyl)ethyl acrylate [(CF ₃ ) ₂ CF(CF ₂ ) ₂ CH ₂ CH ₂ OCOCH=CH ₂ , fluorine content 57% by mass], 3-(perfluoro-3-methylbutyl)-2-hydroxypropyl acrylate [(CF ₃ ) ₂ CF(CF ₂ ) ₂ CH ₂ CH(OH)CH ₂ OCOCH=CH ₂ , fluorine content 52% by mass], 2-(perfluoro-5-methylhexyl)ethyl acrylate [(CF ₃ ) ₂ CF (CF ₂ ) ₄ CH ₂ CH ₂ OCOCH=CH ₂ , fluorine content 61% by mass], 3-(perfluoro-5-methylhexyl)-2-hydroxypropyl acrylate [(CF ₃ ) ₂ CF(CF ₂ ) ₄ CH ₂ CH(OH)CH ₂ OCOCH=CH ₂ , fluorine content 57% by mass], 2-(perfluoro-7-methyloctyl)ethyl acrylate [(CF ₃ ) ₂ CF(CF ₂ ) ₆ CH ₂ CH ₂ OCOCH =CH ₂ , fluorine content 64 mass], 3-(perfluoro-7-methyloctyl)-2-hydroxypropyl acrylate [(CF ₃ ) ₂ CF(CF ₂ ) ₆ CH ₂ CH(OH)CH ₂ OCOCH= CH ₂ , fluorine content 60% by mass], 1H,1H,3H-tetrafluoropropyl acrylate [CHF ₂ CF ₂ CH ₂ OCOCH=CH ₂ , fluorine content 41% by mass], 1H,1H,5H-octafluoropentyl Acrylate [CHF ₂ (CF ₂ ) ₃ CH ₂ OCOCH=CH ₂ , fluorine content 53% by mass], 1H,1H,7H-dodecafluoroheptyl acrylate [CHF ₂ (CF ₂ ) ₅ CH ₂ OCOCH=CH ₂ , fluorine content 59% by mass], 1H,1H,9H-hexadecafluorononyl acrylate [CHF ₂ (CF ₂ ) ₇ CH ₂ OCOCH=CH ₂ , fluorine content 63% by mass], 1H-1-(trifluoromethyl) trifluoroethyl acrylate [(CF ₃ ) ₂ CHOCOCH=CH ₂ , fluorine content 51% by weight], 1H,1H,3H-hexafluorobutyl acrylate [CF ₃ CHFCF ₂ CH ₂ OCOCH=CH ₂ , fluorine content 48% by weight %], 2,2,2-trifluoroethyl methacrylate [CF ₃ CH ₂ OCOC(CH ₃ )=CH ₂ , fluorine content 34 mass %], 2,2,3,3,3-pentafluoropropyl methacrylate [ CF ₃ CF ₂ CH ₂ OCOC(CH ₃ )=CH ₂ , fluorine content 44 mass %], 2-(perfluorobutyl)ethyl methacrylate [CF ₃ (CF ₂ ) ₃ CH ₂ CH ₂ OCOC(CH ₃ )= CH ₂ , fluorine content 51% by mass], 3-(perfluorobutyl)-2-hydroxypropyl pyr methacrylate [CF ₃ (CF ₂ ) ₃ CH ₂ CH(OH)CH ₂ OCOC(CH ₃ )=CH ₂ , fluorine content 47% by mass], 2-(perfluorohexyl)ethyl methacrylate [CF ₃ (CF ₂ ) ₅ CH ₂ CH ₂ OCOC(CH ₃ )=CH ₂ , fluorine content 57 mass %], 3-(perfluorohexyl)-2-hydroxypropyl methacrylate [CF ₃ (CF ₂ ) ₅ CH ₂ CH(OH) CH ₂ OCOC(CH ₃ )=CH ₂ , fluorine content 53 mass %], 2-(perfluorooctyl)ethyl methacrylate [CF ₃ (CF ₂ ) ₇ CH ₂ CH ₂ OCOC(CH ₃ )=CH ₂ , fluorine content 61% by mass], 3-perfluorooctyl-2-hydroxypropyl methacrylate [CF ₃ (CF ₂ ) ₇ CH ₂ CH(OH)CH ₂ OCOC(CH ₃ )=CH ₂ , fluorine content 57% by mass] , 2-(perfluorodecyl)ethyl methacrylate [CF ₃ (CF ₂ ) ₉ CH ₂ CH ₂ OCOC(CH ₃ )=CH ₂ , fluorine content 63% by mass], 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% by mass], 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% by mass], 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 mass %], 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% by mass], 2-(perfluoro-7-methyloctyl)ethyl methacrylate [( _CF3 ) _2CF ( _CF2 ) _{6CH2CH2OCOC ( CH3} ) _{= CH2} , fluorine content 62% by mass ], 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 , containing fluorine 59 mass %], 1H,1H,3H-tetrafluoropropyl methacrylate [CHF ₂ CF ₂ CH ₂ OCOC(CH ₃ )=CH ₂ , fluorine content 51 mass %], 1H,1H,5H-octafluoropentyl methacrylate [CHF ₂ (CF ₂ ) ₃ CH ₂ OCOC(CH ₃ )=CH ₂ , fluorine content 51% by mass], 1H,1H,7H-dodecafluoroheptyl methacrylate [CHF ₂ (CF ₂ ) ₅ CH ₂ OCOC(CH ₃ )=CH ₂ , fluorine content 57% by mass], 1H,1H,9H-hexadecafluorononyl methacrylate [CHF ₂ (CF ₂ ) ₇ CH ₂ OCOC(CH ₃ )=CH ₂ , fluorine content 61% by mass ], 1H-1-(trifluoromethyl)trifluoroethyl methacrylate [(CF ₃ ) ₂ CHOCOC(CH ₃ )=CH ₂ , fluorine content 48 mass %], 1H,1H,3H-hexafluorobutyl methacrylate [CF ₃ CHFCF ₂ CH ₂ OCOC(CH ₃ )=CH ₂ , fluorine content 46 mass %] and the like.

In the ultraviolet curable resin, the ratio of (B) (meth)acrylate monomer to the total of (A) (meth)acrylate oligomer and (B) (meth)acrylate monomer is preferably in the range of 0 to 60% by mass. (B) By containing the (meth)acrylate monomer, it is possible to suppress the occurrence of tackiness in the UV-cured film and to make it difficult for the wear due to friction to occur. On the other hand, by setting the content to 60% by mass or less, it is possible to suppress the unreacted monomer from remaining in the UV-cured film, and to make it difficult for uncured components to bleed out.

Furthermore, (C) the photopolymerization initiator has the action of initiating the polymerization of (A) the (meth)acrylate oligomer and (B) the (meth)acrylate monomer when irradiated with ultraviolet rays. Such photopolymerization initiators include 4-dimethylaminobenzoic acid, 4-dimethylaminobenzoic acid ester, 2,2-dimethoxy-2-phenylacetophenone, acetophenone diethylketal, alkoxyacetophenone, benzyldimethylketal, benzophenone, 3,3 benzophenone derivatives such as '-dimethyl-4-methoxybenzophenone, 4,4'-dimethoxybenzophenone and 4,4'-diaminobenzophenone, alkyl benzoylbenzoates, bis(4-dialkylaminophenyl) ketones, benzyl and benzyl methyl ketal, etc. benzyl derivatives such as benzoin and benzoin isobutyl ether, benzoin isopropyl ether, 2-hydroxy-2-methylpropiophenone, 1-hydroxycyclohexylphenyl ketone, xanthone, thioxanthone and thioxanthone derivatives, fluorene, 2,4,6 -trimethylbenzoyldiphenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2-methyl-1- [4-(methylthio)phenyl]-2-morpholinopropane-1,2-benzyl-2-dimethylamino-1-(morpholinophenyl)-butanone-1 and the like. One of these photopolymerization initiators may be used alone, or two or more thereof may be used in combination. The amount of the (C) photopolymerization initiator in the ultraviolet curable resin is preferably in the range of 0.2 to 5.0 parts by mass with respect to the total of 100 parts by mass of the (A) oligomer and (B) monomer.

In the ultraviolet curable resin, (C) In order to promote the polymerization reaction by the photopolymerization initiator, a tertiary amine photopolymerization accelerator such as triethylamine and triethanolamine, a phosphine photopolymerization accelerator such as triphenylphosphine A thioether-based photopolymerization accelerator such as thiodiglycol may be further added. The amount of these photopolymerization accelerators to be added is preferably in the range of 0.01 to 10 parts by weight per 100 parts by weight in total of the (A) oligomer and (B) monomer.

Moreover, the ultraviolet curable resin may further contain a polymerization inhibitor. By adding a polymerization inhibitor, it is possible to prevent thermal polymerization before UV irradiation. Polymerization inhibitors include hydroquinone, hydroquinone monomethyl ether, p-methoxyphenol, 2,4-dimethyl-6-t-butylphenol, 2,6-di-t-butyl-p-cresol, butylhydroxyanisole, 3 -hydroxythiophenol, α-nitroso-β-naphthol, p-benzoquinone, 2,5-dihydroxy-p-quinone and the like. The content of the polymerization inhibitor is preferably in the range of 0.001 to 0.2 parts by mass with respect to 100 parts by mass in total of the (A) oligomer and (B) monomer.

The surface layer 4 may contain a conductive agent to impart conductivity, and examples of such a conductive agent include those similar to the conductive agent that can be used in the base layer 3 described above. In addition to the conductive agent, the surface layer 4 may contain various additives as required, and is not particularly limited.

When the surface layer 4 is formed using a resin other than an ultraviolet curable resin, a solvent such as methyl ethyl ketone (MEK), acetone, methanol, ethanol, toluene, xylene, hexane, ethyl acetate, chloroform, or isopropyl ether is usually used. Then, the surface layer 4 can be formed by applying a paint in which the above resins and additives are dissolved and dispersed.
Furthermore, even when the surface layer 4 is formed using an ultraviolet curable resin or a resin other than the ultraviolet curable resin, the surface layer 4 contains rubber particles in addition to the triazine resin particles. Or synthetic resin particles, inorganic particles, carbon particles, specifically particles of silicone rubber, acrylic resin, styrene resin, acrylic / styrene copolymer, fluororesin, urethane, urethane acrylate, phenol resin, silica, etc. be able to.

Further, in the present embodiment, the surface layer 4 is not particularly limited, but can be formed, for example, by coating the surface of the base layer 3 with a coating of a resin composition that is a raw material for the surface layer 4. The coating method includes: A die coating method, a roll coating method, a dipping method, a spray method, a comma coating method, or the like can be used.

By the way, in the present embodiment, the toner charge amount (Q/M) is preferably 50 (μC/g) or less. Also, the toner mass (M/A) is preferably 0.25 to 0.35 (mg/cm ² ). By setting it in such a range, it is possible to improve the image quality on a recording medium such as paper.

The thickness of the surface layer 4 can be, for example, 0.1 to 30 μm. By setting the thickness within this range, the electrical properties, mechanical properties, and surface properties of the roller can be easily controlled.

Further, the surface roughness of the surface layer 4, ie, the surface roughness of the roller, is preferably 1 to 20 μm in terms of ten-point average roughness Rz conforming to JIS B 0610. By setting the surface roughness within this range, it is possible to easily obtain good toner transportability.

Next, the image forming apparatus of this embodiment will be described with reference to FIG. The image forming apparatus of this embodiment includes the developing roller 1 of this embodiment.
Specifically, in the image forming apparatus of this embodiment, as shown in FIG. 1, the developing roller 1 is positioned between a toner supply roller 11 for supplying toner and a photosensitive drum 12 holding an electrostatic latent image. The toner 13 is supplied to the surface of the developing roller 1 by the toner supplying roller 11 by rotating the developing roller 1, the photosensitive drum 12, and the toner supply roller 11 in the directions of the arrows in the drawing. The supplied toner is formed into a uniform thin layer by the layering blade 14 . In this state, the developing roller 1 rotates with the photosensitive drum 12 . Attached to the image, the latent image is made visible.
A latent image is formed by charging the surface of the photosensitive drum 12 with the charging roller 15 and exposing image information to the charged surface with the exposure device 16 . Reference numeral 17 in the figure denotes a transfer section, where the toner image is transferred onto a recording medium 18 such as paper. A reference numeral 19 denotes a cleaning portion, and a cleaning blade 20 removes toner remaining on the surface of the photosensitive drum 12 after transfer.
It should be noted that the image forming apparatus of the present embodiment can be further provided with known components that are commonly used in image forming apparatuses (not shown).
In the image forming apparatus of the present embodiment, as the developing roller 1, the developing roller 1 of the present embodiment in which the toner charge amount (Q/M) and the toner mass (M/A) are appropriately adjusted is used. Since it is used, the image quality on a recording medium such as paper can be improved.

Although the embodiments of the present invention have been described above with reference to the drawings, the developing roller and image forming apparatus of the present invention are not limited to the above examples, and the developing roller and image forming apparatus of the present invention include: , may be modified accordingly.

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

(particle)
(a-1) Triazine-based resin particles: melamine resin, average particle size 0.1 μm (manufactured by Nippon Shokubai Co., Ltd., Eposter SS)
(a-2) Triazine-based resin particles: melamine resin, average particle size 0.4 μm (manufactured by Nippon Shokubai Co., Ltd., Eposter S6)
(a-3) Triazine-based resin particles: melamine resin, average particle size 2 μm (manufactured by Nissan Chemical Industries, Ltd., Optobeads 2000ML)
(a-4) Triazine-based resin particles: melamine resin, average particle size 3.5 μm (manufactured by Nissan Chemical Industries, Ltd., Optobeads 3500ML)
(a-5) Urethane particles: average particle size 2 μm (manufactured by Negami Kogyo Co., Ltd., MM120T)
(a-6) Acrylic particles: average particle size 0.15 μm (manufactured by Soken Chemical Co., Ltd., MP-1451)

(Examples 1 to 6, Comparative Examples 1 to 5)
As the developing rollers of Examples 1 to 6 and Comparative Examples 1 to 5, developing rollers each having a shaft member and a base layer and a surface layer sequentially formed on the outer circumference thereof as shown in FIG. 2 were produced.
Specifically, in Examples 1 to 6 and Comparative Examples 1 to 5, an aluminum cored bar having an outer diameter of 7.5 mm was used as the shaft member. A base layer was formed on the surface of the pipe of the shaft member by a die coating method using urethane acrylate (ASBC375, manufactured by Asia Industry Co., Ltd.) and a conductive agent (carbon black (Denka Black, manufactured by Denki Kagaku Kogyo Co., Ltd.)). . After that, a surface layer was formed on the surface of the base layer. For the surface layer, a binder resin (PX31-96, manufactured by Asia Industry) is coated with the particles shown in Table 1 and an initiator (Irg.907, manufactured by BASF) on the surface of the base layer by a roll coating method. Then, it was cured by irradiating with ultraviolet rays to form a surface layer.
For the obtained developing roller, the charge amount per toner unit mass (Q/M) and the toner mass per unit area of the developing roller (M/A) were measured by the measuring method described later. Table 1 shows the results.

(Toner charge amount (Q/M), toner mass (M/A))
The toner charge amount (Q/M) and toner mass (M/A) were measured by the following methods.
A cartridge equipped with each developing roller in Table 1 was installed in an image forming apparatus, and the developing roller was idly rotated at 400 V and 50 PPM without printing. By sucking and taking in the toner, the "total electric charge Q (μC) of the toner" and the "mass M (g) of all the taken-in toner" are measured, and the toner charge amount (Q/M (μC/g )). Further, when the toner charge amount was measured as described above, the toner mass (M/A (mg/cm ² )) was obtained by calculating the area (A) of the developing roller surface portion from which the toner was removed. The results are shown in Table 1. The toner charge amount (Q/M) was 50 (μC/g) or less and the toner mass (M/A) was 0.25 to 0.35 (mg/cm ² ). ) was judged as a good value.

From Table 1, the developing rollers of Examples 1 to 6, in which the surface layer contains triazine-based resin particles having an average particle size of 2 μm or less so that the content and the average particle size satisfy a predetermined relationship, have a toner unit mass of It can be seen that the charge amount (Q/M) per unit area and the toner mass (M/A) per unit area can be set within a predetermined range, and the image quality can be further improved.

According to the present invention, a developing roller capable of appropriately adjusting the amount of charge per unit mass of toner (Q/M) and the mass of toner per unit area of the developing roller (M/A), and image quality are improved. It is possible to provide an image forming apparatus that can be improved.

Reference Signs List 1, 10: developing roller, 2: shaft member, 3: base layer, 4: surface layer,
11: toner supply roller, 12: photosensitive drum (photoreceptor), 13: toner,
14: Lamination blade, 15: Charging roller, 16: Exposure device, 17: Transfer section,
18: recording medium, 19: cleaning section, 20: cleaning blade

Claims (5)

A developing roller comprising a shaft member, a base layer positioned radially outward of the shaft member, and a surface layer positioned radially outward of the base layer and forming a surface,
The surface layer contains triazine-based resin particles having an average particle size of 2 μm or less,
The value obtained by dividing the content (parts by mass) of the triazine-based resin particles with respect to 100 parts by mass of the binder resin contained in the surface layer by the average particle diameter (μm) of the triazine-based resin particles is 350 to 750,
The charge amount per toner unit mass is 50 (μC/g) or less,
and a developing roller having a toner mass of 0.25 to 0.35 (mg/cm ² ) per unit area of the surface of the developing roller. 2. The developing roller according to claim 1, wherein the content (parts by mass) of said triazine-based resin particles with respect to 100 parts by mass of binder resin contained in said surface layer is 1 to 200 parts by mass. 2. The developing roller according to claim 1, wherein the content (parts by mass) of said triazine-based resin particles with respect to 100 parts by mass of binder resin contained in said surface layer is 5 to 120 parts by mass. 4. The developing roller according to any one of claims 1 to 3 , wherein the triazine-based resin particles have an average particle size of 1 μm or less. An image forming apparatus comprising the developing roller according to any one of claims 1 to 4 .

Images