JP5049552B2 - Developing roller, process cartridge, and image forming apparatus - Google Patents

Description

  The present invention relates to a developing roller that is used in contact with a photoreceptor incorporated in an apparatus employing an electrophotographic system such as a copying machine, a printer, or a facsimile receiving apparatus.

  In a copying machine, a facsimile machine, and a printer using an electrophotographic system, a photosensitive member is uniformly charged by a charging roller, and an electrostatic latent image is formed by a laser or the like. Next, the toner in the developing container is uniformly applied on the developing roller with a proper charge by the toner application roller and the toner regulating member, and toner transfer (development) is performed at the contact portion between the photosensitive member and the developing roller. Thereafter, the toner on the photoconductor is transferred to a recording sheet by a transfer roller and fixed by heat and pressure. The toner remaining on the photoconductor is removed by a cleaning blade, and a series of processes is completed.

In these image forming apparatuses, in order to charge a photoreceptor or to visualize an electrostatic latent image, a conductive (electrical resistance) in a semiconductive region of 10 ³ to 10 ¹⁰ Ω · cm is used. ) Is generally used. For example, in a non-magnetic one-component contact development type image forming apparatus, toner is moved from a developing roller pressed against each other to a photosensitive member (drum) to visualize an electrostatic latent image and development is performed. The elastic roller used in such an image forming apparatus has a semiconductive property in which a single or a plurality of resin layers are formed on a conductive rubber layer in order to make a semiconductive roller satisfying a higher level of required quality. Many rollers are used.

  As the polymer elastic material forming these constituent members, a polymer elastomer or polymer foam having rubber elasticity is used, and these are low in hardness and do not contaminate the photoreceptor or transfer member. In addition, it is required to have a characteristic that does not fuse with the toner. Therefore, the materials that make up the polymer elastomer and polymer foam are solid rubber vulcanizates such as isoprene rubber, ethylene propylene rubber, silicone rubber, epichlorohydrin rubber, acrylonitrile butadiene rubber, and liquid raw materials such as polyols cured with isocyanate. Polyurethane etc. are used. Among these, there is an advantage that conductivity can be imparted by both a conductive material and an electrolyte, and there is an advantage that the electrolyte can be used by dissolving in a liquid raw material, and a foam can be formed as necessary. Polyurethanes produced using isocyanate as the main raw material are generally used.

  Image forming apparatus members made of these materials are often required to have electrical conductivity. For example, by mixing conductive materials such as carbon black and metal oxide, or by adding an electrolyte, an image forming apparatus member is made predetermined. It is adjusted to the electrical resistance value.

When used as a developing roller, the roller resistance is preferably 10 ⁵ to 10 ⁹ Ω, which is a semiconductive region. In resistance adjustment using a conductive material such as carbon black or metal oxide, the selection of the conductive material plays an extremely important role in order to stabilize the resistance.

  For example, Patent Document 1 describes a method of stabilizing the resistance of the roller surface layer by selecting the characteristics (oil absorption amount, surface area, particle diameter) of carbon black.

Further, Patent Document 2 describes a method for obtaining a conductive roll in the middle resistance region without causing a significant increase in hardness by using a strong conductive black carbon and a weak conductive black carbon in combination.
Japanese Patent No. 2801724 JP-A-9-90714

In recent years, the performance required for developing rollers used in electrophotographic systems such as copiers, printers, and facsimile machines has become more advanced, and more flexible and low in terms of higher image quality and energy saving. A toner having a melting point is used. Furthermore, in order to achieve stable electrical characteristics and achieve both high image quality and image durability as described above, physical properties with flexibility have been particularly required. In a medium resistance region (10 ⁵ to 10 ⁹ Ω · cm) suitable as a developing roller, the resistance of the resin layer may change greatly due to a subtle difference in the dispersibility of conductive filler such as carbon black. In addition, the resin layer may be remarkably hardened by a conductive filler such as carbon black added to develop the conductivity of the material. In order to impart higher conductivity, the amount of the conductive filler must be increased, and the hardness of the resin layer further increases. Highly conductive carbon black generally has low dispersibility and may impair stability and mechanical properties. For this reason, there is a concern that stable electrical characteristics cannot be obtained, or that the hardness of the resin layer increases and stress is applied to the toner, and the damaged or deteriorated toner mass adversely affects the image quality.

  An object of the present invention is to provide a high-quality developing roller that has a small variation in electrical characteristics due to dispersion in dispersibility and has both appropriate conductivity and flexibility, and that maintains high flexibility while maintaining high flexibility. An object is to provide a conductive developing roller. It is another object of the present invention to provide a process cartridge and an image forming apparatus using such a developing roller.

The present inventors have intensively studied and studied in order to achieve such problems and to provide products satisfying the characteristics required for the developing roller. As a result, the present invention includes a mandrel, in the developing roller having a resin layer which is the uppermost surface layer, and characterized in that said resin layer is a resin component, containing a dye compound and conductive fine particles having a pyrazolone skeleton The present invention relates to a developing roller.

  As a result, it has been found that resistance variations are small, flexibility and conductivity are excellent, and a particularly suitable electrophotographic developing roller is obtained, and a high-quality process cartridge and an image forming apparatus are obtained.

According to the present invention, a mandrel, in the developing roller having a resin layer which is the outermost layer, the resin layer is below a), b), by the inclusion of c), the flexibility and the conductive A developing roller having excellent electrical characteristics and small variations is obtained. Further, a high-quality process cartridge and an image forming apparatus can be obtained by using the developing roller.

a) Resin component b) Dye compound having pyrazolone skeleton c) Conductive fine particles

The present invention is described in detail below.

  Here, regarding the configuration of the developing roller in the present invention, as shown in FIG. 1, at least one elastic layer 3 is provided between the shaft core body 2 and the shaft core body or between the shaft core body 2 and the resin layer 4. The configuration is more preferable in terms of mechanical strength and image quality.

  The developing roller 1 of the present invention is not particularly limited as long as it has a resin layer 4 provided on the outer peripheral surface of a columnar or hollow cylindrical conductive shaft core 2 as shown in FIGS. Is not to be done. A configuration in which at least one elastic layer 3 is provided between the shaft core 2 and the resin layer 4 is more preferable in terms of mechanical strength and image quality.

  The conductive shaft core 2 functions as an electrode and a support member of a conductive member. For example, a metal or an alloy such as aluminum, copper alloy, or stainless steel; iron plated with chromium, nickel, etc .; conductive It is comprised with electroconductive materials, such as a synthetic resin. The outer diameter of the shaft core is usually in the range of 4 to 10 mm.

  The elastic layer 3 has such hardness and elasticity that it is pressed against the photoconductor with an appropriate nip width and nip pressure so that the toner can be supplied to the electrostatic latent image formed on the photoconductor surface without excess or deficiency. It is given to the developing roller. This elastic layer is usually formed of a molded body of rubber material. As the rubber material, various rubber materials conventionally used for conductive rubber rollers can be used. Specific examples of rubbers used for the rubber material include ethylene-propylene-diene copolymer rubber (EPDM), acrylonitrile-butadiene rubber (NBR), chloroprene rubber (CR), natural rubber (NR), and isoprene rubber (IR). ), Styrene-butadiene rubber (SBR), fluorine rubber, silicone rubber, epichlorohydrin rubber, hydride of NBR, urethane rubber and the like can be used alone or in admixture of two or more. Among these, it is preferable to use silicone rubber from the viewpoint of setting performance and the like. Examples of the silicone rubber include polydimethylsiloxane, polymethyltrifluoropropylsiloxane, polymethylvinylsiloxane, polyphenylvinylsiloxane, and copolymers of these polysiloxanes.

  In the elastic layer 3, a conductivity-imparting agent is an essential component, and various additives such as a non-conductive filler, a crosslinking agent, and a catalyst are appropriately blended. As the conductivity-imparting agent, fine particles such as conductive metals such as graphite, carbon black, aluminum, and copper; conductive metal oxides such as zinc oxide, tin oxide, and titanium oxide can be used. Of these, carbon black is preferred because it is relatively easily available and provides good chargeability. Non-conductive fillers include silica, quartz powder, titanium oxide, zinc oxide, calcium carbonate and the like. Examples of the crosslinking agent include di-t-butyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, dicumyl peroxide and the like.

The volume resistivity of the elastic layer 3 is preferably in the range of 10 ³ to 10 ⁸ Ω · cm when a DC voltage of 100 V is applied. For example, when carbon black is used as the conductivity imparting agent, it is blended in an amount of 15 to 80 parts by mass with respect to 100 parts by mass of rubber in the rubber material. The thickness of the elastic layer 3 is preferably in the range of 2.0 to 6.0 mm, and more preferably in the range of 3.0 to 5.0 mm.

  The developing roller in the present invention is characterized in that the resin layer 4 serving as the outermost surface layer of the developing roller contains the following a), b) and c).

a) Resin component b) Dye compound having pyrazolone skeleton c) Conductive fine particles Specific examples of the resin component include amino resins such as polyurethane, polyester, polyether, acrylic, epoxy resin, and melamine resin. Polyurethane and melamine cross-linked resins are particularly preferred from the viewpoints of film strength and toner chargeability. Among them, thermosetting polyether polyurethane and polyester polyurethane are preferably used because they have the flexibility required for a developing roller.

  These thermosetting polyurethane resins are obtained by a reaction between a known polyether polyol or polyester polyol and an isocyanate compound.

  Examples of the polyether polyol include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. Polyester polyols include 1,4-butanediol, 3-methyl-1,4-pentanediol, neopentyl glycol and other diol components, trimethylolpropane and other triol components, adipic acid, phthalic anhydride, terephthalic acid And polyester polyols obtained by condensation reaction with dicarboxylic acids such as hexahydroxyphthalic acid. These polyol components may be prepolymers that are chain-extended in advance with isocyanates such as 2,4-tolylene diisocyanate (TDI), 1,4 diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI) as required.

  Isocyanate compounds to be reacted with these polyol components or prepolymers thereof are not particularly limited, but are aliphatic polyisocyanates such as ethylene diisocyanate, 1,6-hexamethylene diisocyanate (HDI), and isophorone diisocyanate (IPDI). Arocyclic polyisocyanates such as cyclohexane 1,3-diisocyanate and cyclohexane 1,4-diisocyanate, aromatics such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate (TDI) and diphenylmethane diisocyanate (MDI) Blocked isocyanates using isocyanate and copolymers thereof, oxime compounds and alcohol compounds as blocking agents can be used.

  Examples of the dye compound having a pyrazolone skeleton include compounds represented by Formula 1 or Formulas 2 and 3.

  The reason why the function is manifested in the dye form is that the pigment is in a form in which solid fine particles (powder) are dispersed, and thus is not microscopically uniform. In addition, since the dispersibility changes greatly depending on the affinity with the binder resin, the effect is not stably exhibited. It is presumed that the dye form soluble in solvents and resins is uniformly mixed in the binder resin at the molecular level, so that it functions as a carbon black conductive auxiliary agent independent of the dispersibility of the pyrazolone compound as in powders. Is done.

  The dye having such a pyrazolone skeleton is uniformly dissolved without being aggregated and precipitated in the resin component, and the conductivity is further improved. Therefore, there is little variation in the electrical characteristics of the film due to the dispersibility of the filler as in a system in which only a conductive filler such as carbon black is dispersed. In particular, a dye compound having a 2-phenylpyrazolone skeleton provides a more flexible roller because the same degree of conductivity can be obtained with a smaller amount of conductive filler than usual. When higher conductivity is required, it is not necessary to significantly increase the amount of conductive filler added, and flexible physical properties suitable as the outermost surface layer of the developing roller can be obtained.

  The molecular weight of the dye is preferably 150 or more and 600 or less, more preferably 350 or more and 430 or less. The dye in this molecular weight range has a particularly good balance between solubility in the resin and improvement in conductivity, can be applied to various resin components, and a wide range of conductivity is easily obtained. The dye in the present invention is characterized in that it dissolves in the resin component and expresses conductivity, but it should be sufficiently dissolved and dispersed and the precipitate aggregation is very fine and does not affect the image. If it is not completely dissolved, it can be suitably used.

In (Formula 1), (Formula 2) and (Formula 3), R ₁ and R ₂ represent the following groups.
R ₁ : methyl group, phenyl group, 1-pyridyl group, 4-chlorophenyl group R ₂ : phenyl group, 1-pyridyl group, 4-chlorophenyl group The amount of the dye compound added is the resin layer 4 that is the outermost surface layer. The mass content in is preferably 0.05% by mass or more and 10.0% by mass or less, and more preferably 0.1% by mass or more and 5.0% by mass or less. If the amount is less than 0.05% by mass, sufficient effects may not be achieved. If the amount is more than 10.0% by mass, it is difficult to change the mechanical properties of the film or to dissolve it uniformly. there is a possibility.

  As a method for confirming the presence of the dye compound, a layer containing the dye compound is collected, and confirmed by performing a structural analysis of the extracted component using a solvent such as acetone using a Soxhlet extractor or the like. it can.

The developing roller according to the present invention is characterized in that the resin layer 4 contains conductive fine particles.
Examples of the conductive fine particles include fine particles of conductive metals such as carbon black, graphite, aluminum, and copper, and conductive metal oxides such as zinc oxide, tin oxide, and titanium oxide. Of these, carbon black is preferred because it is relatively easily available and provides good chargeability.

The content of carbon black in the conductive resin layer is preferably 5% by mass or more and 25% by mass or less with respect to the resin component because the conductivity of the developing roller can be within a preferable range.
By using the dye compound of the present invention and the conductive fine particles in combination, it is possible to impart higher conductivity than usual. Therefore, even if low conductivity carbon black having generally good dispersibility is used, If the content is within the range, the hardness range suitable for the developing roller can be obtained. When higher conductivity is required, high conductivity can be imparted without using a highly conductive carbon black without decreasing dispersibility and increasing hardness. The average particle size and DBP oil absorption of carbon black to be used are not particularly limited, but from the viewpoint of film strength and conductivity imparting, it is preferable that the average particle size is 12 to 50 nm and the DBP oil absorption is 50 to 150 ml / 100 g.

  The method for producing carbon black is not particularly limited, but those produced by a channel method, a furnace method or the like are preferably used. In particular, oxidized carbon blacks that have been oxidized and imparted with surface functional groups are highly dispersible in the resin component and can be stably dispersed in the resin component of the roller as in the present invention. It is preferable in terms of imparting conductivity.

  The resin layer 4 that is the outermost surface layer may be added with a filler for improving the film reinforcing property and fine particles for controlling the roughness of the roller surface. Examples of the filler for improving the membrane reinforcement include inorganic fillers such as silica, calcium carbonate, precipitated barium sulfate, titanium oxide, talc, clay, kaolin and mica, and fine particles of various organic polymers.

  Furthermore, polyurethane resin, polyester resin, polyether resin, polyamide resin, acrylic resin, polycarbonate resin, or the like can be used as a component of the fine particles for controlling roughness.

  The fine particles for controlling roughness preferably have a volume average particle diameter of 2 to 14 μm. Moreover, it is preferable that the particle addition amount added to a resin layer is 1-20 mass parts with respect to 100 mass parts of resin solid content of a resin layer. The film thickness of the resin layer may be any, but can be appropriately selected from the viewpoint of the resistance of the roller and the self-film reinforcing property, and is preferably 5 to 100 μm.

  The method for forming the outermost resin layer 4 is not particularly limited, and examples thereof include spraying with paint, dipping, roll coating, and the like, and dip coating, ie, described in JP-A-57-5047. The method of overflowing the coating material from the upper end of the immersion tank is simple and excellent in production stability as a method for forming the resin layer, and is generally used.

  FIG. 4 is a schematic view of a dip coating apparatus. A cylindrical immersion tank 25 has an inner diameter slightly larger than the outer diameter of the roller, and has a depth larger than the axial length of the roller. An annular liquid receiving portion is provided on the outer periphery of the upper edge of the immersion tank 25 and is connected to the stirring tank 27. The bottom of the immersion tank 25 is connected to the stirring tank 27.

  The paint in the stirring tank 27 is fed to the bottom of the immersion tank 25 by the liquid feed pump 26. The paint overflows from the upper end of the immersion tank and returns to the agitation tank 27 via the liquid receiving part on the outer periphery of the upper edge of the immersion tank 25. The shaft core body 2 provided with the elastic layer 3 is fixed vertically to the lifting device 28, immersed in the immersion tank 25, and pulled up to form the resin layer 4.

  The process cartridge and the image forming apparatus of the present invention are not particularly limited as long as they have the developing roller of the present invention, such as a copying machine, a facsimile machine, and a printer.

  A printer will be described below as an example of the process cartridge and the image forming apparatus of the present invention equipped with the developing roller of the present invention. In FIG. 3, the developing device 10 includes a developing container containing a non-magnetic toner 8 as a one-component toner, and a developing roller 6 that is positioned in an opening extending in the longitudinal direction in the developing container and is opposed to the photoreceptor 5. The electrostatic latent image on the photoconductor 5 is developed and visualized.

  As shown in FIG. 3, the printer is provided with a photoconductor 5 that is rotated by a rotation mechanism (not shown), and the surface of the photoconductor 5 is uniformly charged around the photoconductor 5 to a predetermined polarity and potential. The charging device 12 and an image exposure device (not shown) that performs image exposure on the surface of the charged photoreceptor 5 to form an electrostatic latent image are arranged. Further, a developing device 10 having a developing roller 6 according to the present invention is disposed around the photosensitive member 5 for developing the toner by attaching toner onto the formed electrostatic latent image. Further, a device 13 for cleaning the surface of the photoconductor 5 after the toner image is transferred to the paper 22 is provided.

  A fixing device 15 for fixing the transferred toner image on the paper 22 is disposed on the conveyance path of the paper 22.

  The preparation method of the dye compound of the Example of this invention is described below.

Preparation Example 1 Synthesis of Dye Compound 4 4-formyl-5-methyl-2-phenyl-3-pyrazolone 4.1 g (20 mmol), 5-methyl-2-phenyl-3-pyrazolone 3.5 g (20 mmol) and ethanol 20 ml And piperidine 1.0ml (0.86g, 10mmol) was added, and it heated and refluxed for 2 hours. After concentration under reduced pressure, the precipitated crystals were collected by filtration and washed thoroughly with water. The crude crystals were recrystallized from a solvent such as ethanol or methylene chloride to obtain the target dye compound 4 (Formula 4).

Preparation Example 2 Synthesis of Dye Compound 8 4-Formyl-2,5-dimethyl-3-pyrazolone 3.2 g (20 mmol), 5-methyl-2-phenyl-3-pyrazolone 3.5 g (20 mmol), ethanol 20 ml and piperidine 1.0 ml (0.86 g, 10 mmol) was added and heated to reflux for 2 hours. After concentration under reduced pressure, 3.5 g (20 mmol) of 5-methyl-2- (4-chlorophenyl) -3-pyrazolone and 5.0 g of 30% hydrochloric acid were gradually added to the precipitated crystals, followed by stirring for 3 hours while maintaining at 60 ° C. . The resulting mixture was allowed to cool to room temperature, and the precipitated crystals were collected by filtration and washed thoroughly with water. The crude crystals were recrystallized from a solvent such as ethanol or methylene chloride to obtain the target dye compound 8 (Formula 5).

Using the methods of Preparation Examples 1 and 2, dye compounds shown in Table 1 below were synthesized. All the compounds shown in Table 1 are soluble in solvents such as acetone, methyl ethyl ketone, and toluene, and have the form of a dye exhibiting a yellow to reddish brown color tone.

  Specific examples and comparative examples according to the present invention will be described below.

  The molecular weight in this example was measured using an ion trap mass spectrometer MS LCQ (manufactured by ThermoQuest) as a measuring instrument. The sample was a 10 ppm methanol solution and measured by the ESI infusion method.

  The sheet for measuring physical properties is prepared by adjusting the dispersion for forming the conductive resin layer to a viscosity of 15 cps, casting it into an aluminum mold so as to have a film thickness of 200 μm, and placing it on a sunflower pedestal so that the viscosity of the paint does not form a film on the surface. Allowed to dry to an extent. Then, it was placed on a horizontal table and allowed to stand at room temperature for 1 day. After drying, it was heated and cured at 140 ° C. for 2 hours, cooled to room temperature, peeled off from the mold, and a sheet of conductive resin layer having a thickness of about 200 μm was produced.

  The volume resistivity in the present invention is measured by punching the sheet produced by the above method into a circle having a diameter of 5 cm, depositing platinum on both surfaces, and then leaving it for 24 hours in an environment of 25 ° C. and 50% RH. Volume resistivity was measured with a voltage load of 100 V using a measuring machine R8340A (manufactured by Advantest). As the numerical value, an average value measured at n = 3 was used.

  The surface hardness of the roller was measured by using a micro rubber hardness meter MD-1 (manufactured by Kobunshi Keiki Co., Ltd.), at a temperature of 25 ° C. and a relative humidity of 50% RH. An average value obtained by measuring three lower end portions was used.

The roller resistance is determined by pressing the developing roller at 20 ° C. and 40% RH using a resistance measuring device shown in FIG. Resistance measurement was performed at 60 rpm, and an average value for 3 seconds was defined as a roller resistance value.
Hereinafter, an example in which the developing roller of the present invention is applied to a laser beam printer will be described.

  Evaluation of image durability was performed by loading the development roller of this example and a comparative example on a modified laser beam printer LBP5500 manufactured by Canon having the configuration as shown in FIG. Image durability was evaluated by printing 10,000 sheets continuously at a printing rate of 2% with non-magnetic one-component black toner in an environment of an air temperature of 23 ° and a relative humidity of 55% RH, and then stopping the printer while outputting a solid white image. The toner adhering to the photosensitive member is peeled off with a tape, and the amount of reduction in reflectance (%) with respect to the reference is measured with a reflection densitometer (TC-6DS / A, manufactured by Tokyo Denshoku Co., Ltd.) to obtain the amount of fog . Next, as an image pattern, a 15 mm square solid black image was printed at the leading edge within one sheet, and then the entire halftone image was printed. The density unevenness of the developing roller period appearing in the halftone portion was visually evaluated to evaluate the ghost. . For the evaluation of the image density, a solid image was output, the density on the paper surface was measured at 9 points using a reflection densitometer (GretagMacbeth RD918), and the average value was calculated.

Example 1
As the shaft core body 2, a SUS-made Φ8 mm metal core was subjected to nickel plating, and a primer-DY35-051 (trade name, manufactured by Toray Dow Corning Silicone) was applied and baked. Next, the shaft core 2 is placed in a mold, and 100 parts by mass of liquid silicone rubber material SE6724A / B (trade name, manufactured by Toray Dow Corning Silicone), carbon black: Talker Black # 7360SB (trade name, Tokai) Cavity formed in the mold with an addition-type silicone rubber composition in which 35 parts by mass of carbon), 0.2 part by mass of silica powder as a heat resistance imparting agent, and 0.1 part by mass of platinum catalyst are mixed Injected into. Subsequently, the mold was heated to vulcanize and cure the silicone rubber at 150 ° C. for 15 minutes, demolded, and further heated at 180 ° C. for 1 hour to complete the curing reaction, and the elastic layer 3 having a thickness of 4 mm was pivoted. It was provided on the outer periphery of the core body 2.

  As the material of the resin layer 4 on the outermost surface, polytetramethylene glycol PTG1000SN (trade name, manufactured by Hodogaya Chemical Co., Ltd.) 100 parts by mass, chain extension isocyanate compound Cosmonate MDI (trade name, manufactured by Mitsui Takeda Chemical Co., Ltd.) 22 masses Parts were mixed stepwise in a MEK solvent and reacted at 80 ° C. for 5 hours in a nitrogen atmosphere to obtain polyurethane polyol A having a weight average molecular weight Mw = 11000 and a hydroxyl value of 26.

  Next, with respect to 100 parts by mass of polyurethane polyol A, 33.4 parts by mass of coronate 2521 (trade name, manufactured by Nippon Polyurethane Industry Co., Ltd.), 15.0 parts by mass of carbon black MA-230 (trade name, manufactured by Mitsubishi Chemical) were prepared. 0.2 parts by mass of the dye compound 1 (Formula 9) in Table 1 obtained in Examples 1 to 5 is mixed with 100 parts by mass of the resin component, and dissolved and mixed in MEK so that the total solid content ratio is 30% by mass. Thereafter, the mixture was uniformly dispersed in a sand mill to obtain a resin solution 1 for forming a resin layer.

About the obtained dispersion liquid, the sheet | seat with a film thickness of about 200 micrometers was produced by the above-mentioned method. The volume resistivity of the obtained sheet was 2.1 × 10 ⁹ Ω · cm.
Furthermore, this resin solution is diluted with MEK to a viscosity of 10 to 13 cps, dip-coated on the elastic layer, dried, and heat-treated at 150 ° C. for 2 hours to have a conductivity of about 15 μm on the outer periphery of the elastic layer. A resin layer was provided to obtain the developing roller of Example 1. The surface hardness of the developing roller measured by the method described above was 35.8.

(Example 2)
A sheet and a developing roller of Example 2 were obtained in the same manner as in Example 1 except that the dye compound 1 of Example 1 was changed to the dye compound 2.

(Example 3)
A sheet and a developing roller of Example 3 were obtained in the same manner as in Example 1 except that the dye compound 1 of Example 1 was changed to the dye compound 3.

Example 4
A sheet and a developing roller of Example 4 were obtained in the same manner as in Example 1 except that the dye compound 1 of Example 1 was changed to the dye compound 4.

(Example 5)
A sheet and a developing roller of Example 5 were obtained in the same manner as in Example 1 except that the dye compound 1 of Example 1 was changed to the dye compound 5.

(Example 6)
A sheet and a developing roller of Example 6 were obtained in the same manner as in Example 1 except that the dye compound 1 of Example 1 was changed to the dye compound 6.

(Example 7)
A sheet and a developing roller of Example 7 were obtained in the same manner as in Example 1 except that the dye compound 1 of Example 1 was changed to the dye compound 7.

(Example 8)
A sheet and a developing roller of Example 8 were obtained in the same manner as in Example 1 except that the dye compound 1 of Example 1 was changed to the dye compound 8.

Example 9
A sheet and a developing roller of Example 9 were obtained in the same manner as in Example 1 except that the dye compound 1 of Example 1 was changed to the dye compound 9.

(Example 10)
A sheet and a developing roller of Example 10 were obtained in the same manner as in Example 1 except that the dye compound 1 of Example 1 was changed to the dye compound 10.

(Example 11)
A sheet and a developing roller of Example 11 were obtained in the same manner as in Example 1 except that the addition amount of Dye Compound 1 in Example 1 was changed to 0.05 part by mass.

(Example 12)
A sheet and a developing roller of Example 12 were obtained in the same manner as in Example 1 except that the amount of dye compound 1 added in Example 1 was changed to 0.10 parts by mass.

(Example 13)
A sheet and a developing roller of Example 13 were obtained in the same manner as in Example 1 except that the addition amount of Dye Compound 1 in Example 1 was changed to 5.0 parts by mass.

(Example 14)
A sheet and a developing roller of Example 14 were obtained in the same manner as in Example 1 except that the amount of dye compound 1 added in Example 1 was changed to 10.0 parts by mass.

(Example 15)
The sheet of Example 15 except that the amount of carbon black MA-230 (trade name, manufactured by Mitsubishi Chemical) in Example 1 was changed from 15.0 parts by mass to 5.0 parts by mass. And a developing roller.

(Example 16)
The sheet of Example 16 was the same as Example 1 except that the amount of carbon black MA-230 (trade name, manufactured by Mitsubishi Chemical) in Example 1 was changed from 15.0 parts by mass to 10.0 parts by mass. And a developing roller.

(Example 17)
The sheet of Example 17 was the same as Example 1 except that the amount of carbon black MA-230 (trade name, manufactured by Mitsubishi Chemical) in Example 1 was changed from 15.0 parts by mass to 25.0 parts by mass. And a developing roller.

(Example 18)
The sheet of Example 18 except that the amount of carbon black MA-230 (trade name, manufactured by Mitsubishi Chemical) in Example 1 was changed from 15.0 parts by mass to 30.0 parts by mass. And a developing roller.

(Example 19)
A sheet and a developing roller of Example 19 were obtained in the same manner as in Example 1 except that the polyurethane polyol A in Example 1 was changed to polyester urethane resin NIPPOLAN 5033 (trade name, manufactured by Nippon Polyurethane Industry Co., Ltd.).

(Example 20)
A sheet and a developing roller of Example 20 are obtained in the same manner as in Example 1 except that the polyurethane polyol A in Example 1 is changed to thermoplastic urethane resin Rezamin P-1045 (trade name, manufactured by Dainichi Seika Kogyo Co., Ltd.). It was.

(Example 21)
Example 3 was the same as Example 1 except that 33.4 parts by mass of Coronate 2521 (trade name, manufactured by Nippon Polyurethane Industry Co., Ltd.) in Example 1 was changed to 25.0 parts by mass of melamine resin Cymel 712 (trade name, manufactured by Nippon Cytec Co., Ltd.). Thus, a sheet and a developing roller of Example 21 were obtained.

  The comparative example of the present invention will be described in detail below.

(Comparative Example 1)
A sheet and a developing roller of Comparative Example 1 were obtained in the same manner as in Example 1 except that the dye compound 1 in Example 1 was omitted.

(Comparative Example 2)
Comparative Example 2 is the same as Comparative Example 1 except that 15.0 parts by mass of carbon black MA-230 in Comparative Example 1 is changed to 40.0 parts by mass of carbon black MA-11 (trade name, manufactured by Mitsubishi Chemical). A sheet and a developing roller were obtained.

(Comparative Example 3)
Comparative Example 3 is the same as Comparative Example 1 except that 15.0 parts by mass of Carbon Black MA-230 in Comparative Example 1 is changed to 10.0 parts by mass of Carbon Black FW-200 (trade name, manufactured by Degussa Japan). Sheet and a developing roller were obtained.

(Comparative Example 4)
A sheet and a developing roller of Comparative Example 4 were obtained in the same manner as in Example 1, except that the dye compound 1 in Example 1 was changed to 4,5-diphenylimidazole (Kishida Chemical Co., Ltd., Formula 10).

(Comparative Example 5)
The sheet and developing roller of Comparative Example 5 were the same as Example 1 except that Dye Compound 1 in Example 1 was changed to 2- (1-naphthyl) -5-phenyloxazole (Kishida Chemical Co., Formula 11). Got.

(Comparative Example 6)
Comparative Example 6 was carried out in the same manner as in Example 1 except that the dye compound 1 in Example 1 was changed to anthraquinone dye Philamid Blue R (trade name, CI Solvent Blue 132, manufactured by Ciba Specialty Chemicals). Sheet and a developing roller were obtained.

(Comparative Example 7)
Comparative Example 7 was performed in the same manner as in Example 1 except that the dye compound 1 in Example 1 was changed to pyrazolone pigment Irgarite Orange P (trade name, CI Pigment Orange 13 manufactured by Ciba Specialty Chemicals). Sheet and a developing roller were obtained.

 Volume resistivity was measured about the sheet | seat of Examples 1-21 and Comparative Examples 1-6 obtained as mentioned above. Further, resistance variation and surface hardness of the obtained developing roller were measured.

  The axial resistance variation (Δ) of the roller is determined by applying a load of 500 g on both ends of the shaft core and pressing the roller against the metal drum while rotating the roller at a speed of 60 rpm. Apply a voltage of 50V, measure the maximum and minimum values of resistance at 3 points from the roller ends and 3 points at the center, 1- (maximum resistance value / minimum resistance value) Is the resistance variation in the axial direction.

  The circumferential resistance variation (Δ) of the roller is determined by applying a load of 500 g on both ends of the shaft core and pressing the roller against the metal drum while rotating the roller at a speed of 60 rpm. A voltage of 50 V was applied, the maximum value and the minimum value of the resistance value in one circuit were measured, and the value of 1- (maximum value of resistance value / minimum value of resistance value) was regarded as resistance variation in the circumferential direction.

  The resistance variation between roller samples was applied to a metal drum while applying a load of 500 g on both ends of the shaft core and rotating the roller at a speed of 60 rpm, and a voltage of 50 V between the roller and the metal drum. Was applied, and the maximum and minimum resistance values of the entire roller were measured. A value of 1- (maximum resistance value / minimum resistance value) was defined as resistance variation between roller samples.

The above measurement results were evaluated according to the following criteria.
A: Resistance variation of 0 or more and less than 0.5 ○: Resistance variation of 0.6 or more and less than 1.0 Δ: Results of resistance variation of 1.0 or more are shown in Tables 2 to 5.

Next, the obtained developing roller was evaluated for image durability by the method described above. The fog, ghost and image density were evaluated according to the following criteria.

Fog ◎: Less than 3% ○: 3% or more and less than 5% △: 5% or more ghost ◎: No ghost observed ○: Very slight ghost recognized △: Remarkable ghost recognized

Image density (solid image)
◎: Concentration is 1.3 or more ○: Concentration is 1.1 or more and less than 1.3 Δ: Concentration is less than 1.1

The above results are shown in Tables 6-8.

  Examples 1-21 show high electroconductivity, without increasing the content of an electroconductive filler remarkably for the electroconductive improvement by a dye compound. Therefore, the resistance variation of the roller is small and the roller is flexible and shows high image quality. In particular, the rollers of Examples 4, 5, and 6 in which the molecular weight of the dye compound is 350 to 430 satisfy both resistance resistance suppression, conductivity, and flexibility at a high level, and high-quality images are obtained.

  On the other hand, Comparative Example 2 containing carbon black at a high ratio in order to develop conductivity with low-conductivity carbon black shows a significant increase in hardness, causing image defects. Further, in Comparative Example 3 in which conductivity is imparted using highly conductive carbon black, there is a marked increase in resistance variation and image defects due to leakage. Further, Comparative Example 1 that does not contain the dye compound of the present invention, imidazole-based, oxazole-based, anthraquinone-based dye compounds, and pyrazolone compounds in the form of pigments with extremely low solubility do not provide a suitable conductivity as a developing roller, and image A decrease in quality was observed.

It is a conceptual diagram which shows an example of the developing roller of this invention. It is a conceptual diagram which shows the cross section of an example of the developing roller of this invention. 1 is a schematic configuration diagram illustrating an example of a process cartridge and an image forming apparatus of the present invention. It is a conceptual diagram which shows an example of a liquid circulation type dip coating apparatus. It is a conceptual diagram which shows an example of a roller resistance measuring machine.

Explanation of symbols

1: Developing roller 2: Shaft core 3: Elastic layer 4: Conductive resin layer 5: Photoreceptor 6: Developing roller 7: Toner supply roller 8: Toner 9: Regulator blade 10: Developing device 11: Laser beam 12: Charging Device 13: Cleaning device 14: Cleaning charging device 15: Fixing device 16: Driving roller 17: Transfer roller 18: Bias power source 19: Tension roller 20: Transfer conveyance belt 21: Driven roller 22: Paper 23: Paper feed roller 24: Adsorption roller 25: immersion tank 26: liquid feed pump 27: stirring tank 28: lifting device 29: internal resistance 30: metal electrode roller

Claims (9)

A mandrel, in the developing roller having a resin layer which is the outermost layer,
Developing row La, characterized in that the resin layer is a resin component, containing a dye compound and conductive fine particles having a pyrazolone skeleton. The developing roller according to claim 1, wherein the dye compound is represented by any one of (Formula 6) to (Formula 8):

(In (Formula 6), R ₁ represents a methyl group or a phenyl group, and R ₂ represents a phenyl group, a 4-chlorophenyl group, or a 1-pyridyl group),

(In (Formula 7), R ₁ represents a methyl group or a phenyl group, R ₂ represents a phenyl group or a 4-chlorophenyl group, R ₃ represents a methyl group, R ₄ represents a phenyl group, a 1-pyridyl group or Represents 4-chlorophenyl group),

(In (Formula 8), R ₁ represents a methyl group, R ₂ represents a phenyl group, 1-pyridyl group or 4-chlorophenyl group, R ₃ represents a methyl group, and R ₄ represents a methyl group or a phenyl group. Show) The developing roller according to claim 1, further comprising an elastic layer between the shaft core and the resin layer . The developing roller according to claim 1, wherein the dye compound has a molecular weight of 350 or more and 430 or less . The developing roller according to any one of claims 1 to 4 , wherein a mass content of the dye compound is 0.1% by mass or more and 5.0% by mass or less with respect to the resin component . The developing roller according to claim 1 , wherein the resin component is a urethane resin or a melamine cross-linked resin . The developing roller according to any one of claims 1 to 5 wherein the resin component is a thermosetting polyurethane resin. A process cartridge comprising the developing roller according to claim 1. An image forming apparatus comprising the developing roller according to claim 1.

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