WO2007000820A1 - Charging roller - Google Patents

Abstract

This invention provides a charging roller that can form a high-quality toner image. The charging roller comprises a support shaft and at least one resin layer provided on the circumferential surface of the support shaft. The resin layer comprises a base resin material and a carbon black dispersed in the base resin material. The carbon black has a number average particle diameter of Feret's diameters of 5 to 300 nm and contains not less than 5%, on the basis of number of particles, of primary particles.

Description

 Specification

 Charging roller

 Technical field

 The present invention relates to a charging roller used in an image forming apparatus employing an electrophotographic process such as an electrophotographic copying machine or a printer.

 Background art

 [0002] Generally, in a copying machine or printer that employs an electrophotographic process, a charger is employed to uniformly charge a photosensitive member. As charging devices, various so-called contact charging devices that generate less ozone have been proposed, and charging rollers have already been put into practical use from the viewpoint of uniform charging properties and high-speed charging properties. As an image forming apparatus using this type of charging roller, for example, Patent Document 1 is known.

 [0003] The image forming apparatus described in Patent Document 1 has a configuration in which a charging roller is rotatably contacted with an outer peripheral surface of a photosensitive drum, and is driven to rotate by the rotation of the photosensitive drum or a motor. It is configured to be able to be forcedly rotated by, for example. A power source is connected to the charging roller, and a noise voltage consisting of the power source DC and AC component force is applied to charge the photosensitive drum in a state where the amount of generated ozone is extremely small. This patent document 1 introduces a DC bias of ± 500 to 1000V as a normal applied voltage and an AC bias of 1 OOHz ~: LOKHz ゝ 200 to 3500V (p-p) superimposed on this !, The

 [0004] The charged photosensitive drum is irradiated with light, and an electrostatic latent image is formed on the surface of the photosensitive drum. The toner is developed by the toner. In order to realize high-quality image formation, the charger is sensitive. It is desired that the surface of the photoconductor drum can be uniformly charged. In Patent Document 1 described above, in order to ensure uniform chargeability, a cored bar as a charging roller and a rubber layer such as chloroprene rubber, urethane rubber, silicon rubber or the like, which is a conductive elastic member provided on the outer periphery thereof, or the like. Introduce a structure in which these sponge layers and a protective layer (release coating layer) composed of a 0.01-m thick release fluorine-based resin or silicon resin layer are provided on the outermost layer. .

In order to impart conductivity to these protective layers and rubber layers, it is generally widely adopted that carbon black is dispersed in the base material of each layer. Patent Document 1: Japanese Patent Laid-Open No. 2004-246120

 Disclosure of the invention

 Problems to be solved by the invention

 [0005] However, with the recent trend toward higher image quality, there is a growing demand for images that are closer to printing. In charging rollers using carbon black available in the market, When developing an image (solid latent image), uneven density may be pointed out as a problem. This is due to the demand for high image quality close to printing even at a level where there is no problem with conventional images. According to the study by the inventors, this is due to the fact that the electric conductivity varies depending on the part of the charging roller, and as a result, the electric potential with respect to the photosensitive member varies slightly. As a result of intensive studies on this cause, it was found that carbon black dispersed in each layer was one of the causes.

 [0006] Normally, carbon black exists as secondary particles, that is, aggregates (also referred to as structures) in which a plurality of basic particles are chemically and physically bonded (see FIG. 5). This agglomerate has a complex agglomerated structure branched into irregular chains. Moreover, since the aggregates also form secondary aggregates due to Van der Waals force, simple aggregation, adhesion, and entanglement, it was difficult to obtain a sufficient micro-dispersed structure. In addition, it may have a complicated shape, and even when dispersed in the medium of each layer of the above-described charging roller, it is difficult for these yarns and composites to exhibit uniform conductivity.

 [0007] In particular, the mainstream force is the use of silicon or urethane as the base material of the rubber layer. The poor conductivity of these base materials and carbon black results in poor dispersibility. This is one of the reasons why it is difficult to achieve the rate.

 [0008] Further, since the protective layer is subjected to mechanical contact and friction with the photoreceptor, there is a problem that the electrical characteristics change over time due to separation of the aggregate from the surface layer.

 [0009] Accordingly, an object of the present invention is to provide a charging roller capable of forming a high-quality and uniform toner image.

 Means for solving the problem

[0010] The above-mentioned objects are achieved by the following (1) to (9).

(1) having a support shaft, and at least one resin layer formed on the peripheral surface of the support shaft, The resin layer is characterized in that carbon black having a ferret diameter number average particle diameter of 5 to 300 nm and primary particles of 5% or more on a number basis is dispersed in the base resin material. And charging roller.

 (2) The resin layer includes a plurality of resin layers, and the carbon black is dispersed in at least one resin layer among the plurality of resin layers. The charged roller described.

 (3) The plurality of resin layers include a base rubber layer formed on the support shaft, and a surface layer provided on the outer peripheral side from the base rubber layer. Charging port.

 (4) The charging roller according to (3), wherein the carbon black is dispersed in the base rubber layer.

 (5) The charging roller according to (3), wherein the carbon black is dispersed in the surface layer.

 (6) The charging roller according to (3), wherein an intermediate layer is provided between the base rubber layer and the surface layer.

 (7) The charging roller according to (6), wherein the carbon black is dispersed in the intermediate layer.

 (8) The charging roller according to (1), wherein the surface of the carbon black is surface-treated with an organic compound.

 (9) The charging roller according to (8), wherein the organic compound includes at least a phenol compound and / or an amine compound.

The primary particles referred to in this application will be described. Ordinary carbon black exists in the form of aggregates, but these aggregates are in a form in which a plurality of basic particles are chemically aggregated physically. As used herein, primary particles refer to the basic particles. However, it does not refer to the basic particles in the state of constituting the aggregate, but refers to particles that are separated and separated stably from the aggregate force. As used herein, secondary particles refer to aggregates formed by aggregation of basic particles. Here, secondary aggregates in which aggregates are aggregated are also collectively referred to as secondary particles in the present application. FIG. 1 is a diagram for explaining the relationship between secondary particles and basic particles. The state in which the basic particles are aggregated is defined as secondary particles. Fig. 2 shows the state in which the basic particles constituting the secondary particles are separated from the secondary particles and exist stably, and the particles existing as a single basic particle are defined as primary particles.

 [0013] Hereinafter, this will be described in detail.

 (1) Number average particle diameter

 The carbon black of the present invention has a ferret diameter number average particle diameter in the range of 5 to 300 nm. Preferably, 10 to: LOOnm, particularly preferably 10 to 80 nm.

 By taking such a range, for example, it can be finely dispersed on the surface of the resin molded product, and the surface properties can be improved.

 [0014] Here, the number average particle diameter of the ferret diameter is measured with respect to carbon black primary particles and secondary particles that exist stably. In the case of carbon black existing as an aggregate, the aggregate is an object to be measured, and the basic particles in the aggregate are not measured.

 In order to control this number average particle size, the carbon black existing as aggregates is appropriately selected so that the basic particle diameter of the carbon black falls within the above range, or the aggregate is divided into primary particles. This can be achieved by changing the time conditions.

 The number average particle diameter of the ferret diameter can be observed with an electron microscope.

 When calculating the number average particle size of the Frere diameter from a single carbon black, the image is magnified 100,000 times with a scanning electron microscope (SEM), and 100 particles are appropriately selected and calculated.

 [0016] It should be noted that when obtaining the average particle size of carbon black, such as sallow, carbon black is magnified 100,000 times with a transmission electron microscope (TEM), and 100 particles are selected as appropriate. May be issued.

 The ferret diameter used in the present invention represents the maximum length of each carbon black particle in any one direction over the plurality of carbon black particles photographed by the electron microscope. The maximum length is the distance between parallel lines when two parallel lines that are perpendicular to the above-mentioned arbitrary direction and are in contact with the outer diameter of the particle are drawn.

For example, in FIG. 3, a photograph 30 of carbon black particles 200 taken with an electron microscope 30 As for 0, any one direction 201 is defined. The distance between the two straight lines 202 perpendicular to the arbitrary one direction 201 and in contact with each force single bon black particle 200 is the free diameter 203.

 [0019] The carbon black of the present invention preferably has a number average particle diameter of the ferret diameter of the primary particles of 2 to 100 nm. In particular, it is 3 to 80 nm. By using carbon black in such a range, the strength can be increased when dispersed in a resin molding. Alternatively, the gloss of the molded product can be improved, or the finished state can be made beautiful. The method for measuring the number average particle size of the primary particles is in accordance with the method for measuring the number average particle size of the carbon black. However, the number of measured particles shall be 100 primary particles.

 [0020] (2) —Ratio of secondary particles

 The carbon black of the present invention contains 5% or more primary particles in the carbon black based on the number. The upper limit is 100%. These ratios vary depending on the industrial field to which they are applied. However, the higher the proportion of primary particles present, the better the performance of the product in the industrial field to which it is applied. If it is a resin molding, mechanical strength, surface glossiness, etc. will improve. Specifically, it is preferable in the order of 10% or more, 20% or more, 30% or more, 40% or more, 50% or more. The ratio of primary particles is measured in the same manner using the above-mentioned electron microscope, but the number of measured particles is calculated by counting the primary particles present in 1000 carbon black particles.

 [0021] (3) Carbon black

 In the carbon black of the present invention, it is preferable that the surface of the carbon black particles finally present stably be surface-treated (including grafting) with an organic compound or the like.

 The grafting rate is defined below.

 Grafting rate is expressed as ((Υ-Ζ) / Ύ) X 100 (%), where Y is the amount of organic compound before reaction and を is the extracted organic compound.

 The graft ratio is preferably 50% or more. The more uniformly the surface is treated, the better the dispersibility.

[0022] The carbon black of the present invention preferably has at least a surface grafted with a force having an active free radical, which will be described later, or an organic compound that can be generated. By adopting such a configuration, not only dispersion in the medium is improved, but also mechanical strength is improved. It is possible to contribute.

 [0023] (4) Manufacturing method of carbon black

 A suitable method for producing the carbon black of the present invention will be described.

 A suitable production method that can be used in the present invention includes at least the following steps.

 (A) a surface treatment step of treating the surface of carbon black containing secondary particles that also have a force having active free radicals or an organic compound that can be generated, and at least agglomeration (structure) force of the basic particles;

 (B) A step of imparting mechanical shearing force to carbon black containing at least secondary particles to form primary particles, and grafting an organic compound into the separated particles separated from the secondary particles.

 [0024] Hereinafter, (A) and (B) will be described in detail.

 (A) Surface treatment process for treating the surface of carbon black containing secondary particles that have active free radicals or organic compounds that can be generated and also have at least basic particle agglomeration (structure) forces

 In this step, the surface of carbon black that also has an agglomeration force is surface-treated with the organic compound.

 In this step, radicals are generated on the surface of the structure, which is the smallest agglomeration unit, by heat or mechanical force, and the surface is treated with an organic compound that can capture these radicals. This step effectively reduces the re-aggregation sites that have been agglomerated due to the strong agglomeration force between the carbon blacks, and prevents the primary particles of the structure and carbon black from aggregating and adhering.

Here, the surface treatment includes a treatment for adsorbing the surface with an organic compound and a treatment for grafting the organic compound. In order to stabilize the particles after the formation of primary particles, it is preferable that the organic compound is grafted on the entire surface of the secondary particles on the portion other than the surface separated from the secondary particle force! It is preferable to graft an organic compound on the surface of the carbon black in this step in order to make primary particles exist stably after the grafting step described later.

[0026] Examples of surface treatment methods include carbon black aggregates and active free radicals. Surface treatment is possible by mixing force or organic compounds that can be produced. In this surface treatment, it is preferable to include a mixing step for applying a mechanical shearing force. In other words, the surface of the carbon black secondary particles is activated in the process of applying mechanical shearing force, and the organic compound itself is also activated by shearing force, resulting in a so-called radical state. As a result, it is estimated that the drafting of organic compounds on the carbon black surface is likely to be promoted.

 In the surface treatment step, an apparatus capable of applying a mechanical shearing force is preferable.

 In the present invention, the mixing device used in the surface treatment step is preferably a vorvo system mixer (manufactured by Thermo Electron), a refiner, a single screw extruder, a twin screw extruder, a planetary screw extruder, A conical screw extruder, continuous kneader, sealed mixer, Z-type kneader, etc. can be used.

 [0028] When the above apparatus is used during the surface treatment process, it is preferable to set so that the degree of mixture filling in the mixing zone in the mixer is 80% or more. The degree of fullness is calculated by the following formula.

 Z = Q / A

Z: Filling degree (%) Q: Filling volume (m ² ) A: Mixing space void volume (m ² )

[0029] That is, the mechanical shearing force can be uniformly applied to the entire particles by making the state full at the time of mixing. When the degree of fullness is low, the transmission of shearing force is insufficient, the activity of carbon black and organic compounds cannot be increased, and grafting may not progress easily.

 [0030] At the time of mixing, the temperature of the mixing zone is preferably equal to or higher than the melting point of the organic compound, preferably within the melting point + 200 ° C, and more preferably within the melting point + 150 ° C. When plural kinds of organic compounds are mixed, it is preferable to set the temperature with respect to the melting point of the organic compound having the highest melting point.

[0031] At the time of mixing, surface treatment is performed by using electromagnetic waves such as ultrasonic waves, microwaves, ultraviolet rays and infrared rays, ozone action, oxidizing agent action, chemical action and Z or mechanical shear force action in combination. It is possible to change the process time. The mixing time is about 15 seconds to 120 minutes depending on the desired degree of surface treatment. Preferably 1 ~: in LOO minutes is there.

 [0032] The organic compound used for the surface treatment is preferably added in the range of 5 to 300 parts by weight with respect to 100 parts by weight of the carbon black to perform the surface treatment step. More preferably, it is 10 to 200 parts by weight. By adding the organic compound in such a range, the organic compound can be uniformly attached to the surface of the bonbon black, and further, sufficient to attach to the separation surface generated when the secondary particles are formed. The amount can be made small. For this reason, it is possible to effectively prevent the decomposed primary particles from aggregating again, and carbon black produced by an organic compound that is excessively present in the finished carbon black, which is generated when added in excess of the amount of added calories. The possibility of losing inherent properties is reduced.

 (B) A step of applying mechanical shearing force to carbon black containing at least secondary particles to form primary particles, and grafting an organic compound onto the separated surface where the secondary particle force is separated. This is a step of cleaving the carbon black in which the re-aggregation sites are reduced in the surface treatment step to form primary particles from secondary particles, and at the same time grafting onto the surface with an organic compound to form stable primary particles. That is, for example, a mechanical shearing force is applied to the carbon black surface-treated with the organic compound, and the organic compound is grafted on the agglomerated portion of the basic particle while causing cracks in the agglomerated portion of the basic particle, thereby reaggregating the carbon black. Will be suppressed. By applying mechanical shearing force continuously to the carbon black, the cracked part is expanded, and the organic compound is grafted to the separation surface generated by the cleavage while forming primary particles, and finally separated as primary particles In the step, the active part capable of agglomeration is not present, so that it is present as a stable secondary particle. In this case, since the same mechanical shearing force is applied to the added organic compound, the organic compound itself is also activated by the mechanical shearing force, and the grafting is promoted.

 [0034] In the present specification, "carbon black in which an organic compound is grafted" means carbon black in which an organic compound part is grafted on a carbon black part. In addition, “grafting” as defined here is defined by Jean-Baptiste Donnet et al. In his book “Carbon Black” (published on May 1, 1978 by Kodansha). The force is the irreversible addition of an organic compound to a substrate such as Bon Black.

[0035] The grafting step generates or generates a force having an active free radical at least in a crack portion. This is a step of grafting an organic compound that can be processed. Also, it may be executed simultaneously or as a separate process during the progress of the surface treatment process.

 [0036] There are various means for causing the above cracks, such as irradiation of electromagnetic waves such as ultrasonic waves, microwaves, ultraviolet rays, and infrared rays, ozone action, oxidant action, chemical action, and mechanical shear force action. Form can take.

 In the present invention, it is preferable to cause a crack by applying at least a mechanical shearing force. It is desirable to place the carbon black (structure) surface-treated with an organic compound in a place where mechanical shearing force is applied and to adjust the surface-treated carbon black from the structure to primary particles. When applying this mechanical shearing force, other means for causing cracks described above may be used in combination.

 The mechanical shearing force here is preferably a shearing force similar to the mechanical shearing force in the surface treatment step described above.

 [0038] As described above, the action of mechanical shearing force can generate active free radicals by breaking the chain inside carbon black, which is not a force when carbon black is atomized from aggregates to primary particles. It can be carried out. The organic compound capable of generating or having a free radical used in the present invention is an organic compound that can be cleaved under the action of a mechanical shear force field to have or generate an active free radical, for example. Contains compounds. If the active free radicals cannot be sufficiently formed only by the action of mechanical cutting force, they are exposed to electromagnetic waves such as ultrasonic waves, microwaves, ultraviolet rays, and infrared rays, under the action of ozone, or under the action of an oxidizing agent. , The number of active free radicals can be complemented.

[0039] Polylab system mixer (manufactured by Thermo Electron), refiner, single screw extruder, twin screw extruder, planetary screw extruder, cone screw extruder, continuous kneading machine Machines, sealed mixers, Z-types, etc. can be used. The conditions for applying the mechanical cutting force are preferably the same as those for the surface treatment described above from the viewpoint of effectively applying the mechanical shearing force. In addition, by using these devices, mechanical energy can be imparted to the entire particle uniformly effectively and continuously, so that grafting can be performed efficiently and uniformly. Is preferable. [0040] In the surface treatment step and the grafting step, the organic compound to be added may be added gradually or intermittently so that the organic compound becomes a predetermined amount, Add a certain amount in advance at the start of the surface process, and run until the grafting process! /.

 The organic compound used in the grafting step as the material to be grafted with the organic compound used in the surface treatment step as the surface treatment material may be the same or different.

 [0041] The grafting step described above is preferably carried out under conditions not lower than the melting point of the organic compound used. The upper limit of the temperature condition is particularly preferably within the melting point of the organic compound + 200 ° C., more preferably within the melting point + 150 ° C., from the viewpoint of promoting the graft reaction and fragmentation of the primary particles. When a plurality of types of organic compounds are mixed, it is preferable that the temperature is set with respect to the melting point of the organic compound having the highest melting point.

 [0042] The above-described mechanical shearing force application time depends on the amount and scale of the sample, but in order to fully execute the process, it is 1 minute to 100 minutes to improve the uniformity of the reaction. It is preferable from the viewpoint.

 [0043] In the production method of the present invention described above, it is preferable to apply mechanical shearing force by mixing carbon black and an organic compound described later without using a solvent. As the reaction gives a shearing force at or above the melting temperature of the organic compound, the organic compound becomes liquid, so that it can evenly fit on the surface of the solid carbon black and effectively advance the reaction. . When a solvent is used, the uniformity is improved, but the energy transfer when applying a mechanical shearing force is reduced, so the level of activity is reduced and the graphing is effective. It is estimated that it will be difficult to proceed.

[0044] The method for adjusting the amount of primary particles is not particularly limited! /, But can be adjusted by changing the conditions for applying the mechanical shearing force described above. More specifically, the mechanical shearing force can be changed by adjusting the mixing degree of the mixing zone in the mixer for applying the shearing force to 80% or more and changing the filling degree. The proportion of primary particles can be adjusted. Furthermore, it can also be adjusted by changing the stirring torque at the time of mixing. As a method for adjusting this torque, in addition to the above-mentioned fullness, it can also be controlled by the stirring rotation speed and the stirring temperature. More specifically, the temperature during mixing Lowering the degree tends to increase the viscosity of the organic compound in the molten state, resulting in higher torque and consequently increased shear force. That is, the abundance of primary particles increases.

 [0045] 2) Carbon black as a starting material

 Examples of carbon black that can be used include carbon black having a force-aggregate structure in which any commercially available carbon black such as furnace black, channel black, acetylene black, and lamp black can be used. This aggregate structure means a carbon black that has been formed into a secondary particle that is formed by agglomeration of primary particles, which are basic particles, and has a structure structure, and also has a so-called aggregate force of primary particles. . In addition, surface treatment of organic compounds on monobon black has sufficient oxygen-containing functional groups such as carboxyl groups, quinone groups, phenol groups, and rataton groups on the surface of carbon black and layer surfaces to facilitate the graft reaction. It is desirable that there are many active hydrogen atoms at the periphery. Therefore, it is preferable that the carbon black used in the present invention has an oxygen content of 0.1% or more and a hydrogen content of 0.2% or more. In particular, the oxygen content is 10% or less and the hydrogen content is 1% or less. Here, the oxygen content and the hydrogen content are respectively obtained by dividing the number of oxygen elements or the number of hydrogen elements by the total number of elements (sum of carbon, oxygen and hydrogen elements).

 By selecting such a range, the surface treatment of the organic compound onto the carbon black can facilitate the graft reaction.

 [0046] Further, by selecting the above-mentioned range, it is possible to reliably graft an organic compound that has a free radical and can be generated, or the reaggregation preventing effect is enhanced. When the oxygen content and hydrogen content on the surface of carbon black are below the above ranges, gas phase oxidation such as heated air oxidation or ozone oxidation, or nitric acid, hydrogen peroxide, potassium permanganate, sodium hypochlorite Alternatively, the oxygen content and hydrogen content of carbon black may be increased by a liquid phase acid treatment with bromine water or the like.

 [0047] 3) Organic compounds

Organic compounds used for surface treatment of carbon black in the surface treatment process or for grafting to a single bon black in the grafting process have free radicals. An organic compound that can be force or produced.

 [0048] In the organic compound capable of generating a free radical, the conditions for generating the free radical are not particularly limited. However, in the case of the organic compound used in the present invention, the free radical is removed during the grafting step. It is necessary to be in the possessed state. The organic compound includes at least a compound capable of generating a free radical by electron transfer, a compound capable of generating a free radical by thermal decomposition, and a compound capable of generating a free radical as a result of the structure of the compound being cleaved by shearing force or the like. preferable.

 [0049] The organic compound capable of generating force or having a free radical used in the present invention preferably has a molecular weight of 50 or less as an upper limit, preferably 1500 or less. . By adopting an organic compound having such a molecular weight range, it is possible to obtain a carbon black whose surface is substituted with an organic compound having a somewhat large molecular weight, and re-aggregation of the formed primary particles can be suppressed. In addition, by setting the molecular weight to 1500 or less, the characteristics of the carbon black itself, which does not cause excessive surface modification and the characteristics of the organic compound grafted on the surface, are sufficiently exhibited. Can be demonstrated.

 [0050] The organic compounds used in the surface treatment step and the grafting step may be the same or different, and plural types of organic compounds may be added to each step. In order to control the reaction temperature and simplify other conditions, it is desirable that the organic compounds used in the surface treatment process and the grafting process be the same.

 [0051] Examples of the organic compound include organic compounds capable of capturing free radicals on the carbon black surface of phenolic compounds, amine compounds, phosphate ester compounds, and thioether compounds. it can.

 [0052] As these organic compounds, so-called anti-oxidation agents and light stabilizers are preferable. More preferably, a hindered phenol and a hindered amine system can be mentioned. Moreover, antioxidants of phosphate ester compounds, thiol compounds, and thioether compounds can also be used. A plurality of these organic compounds may be used in combination. Depending on the combination, various surface treatment characteristics can be exhibited.

[0053] These organic compounds have an isocyanate group in order to control the reaction reliably. Preferably not. That is, when an organic compound having excessive reactivity is used, a uniform grafting reaction is difficult to be formed, and it may be necessary to use a large amount of reaction time and amount of the organic compound. The reason for this is not clear, but when an organic compound with high reactivity as described above is used, the reaction proceeds in addition to the surface active sites and is formed by the mechanical shear force that is the original purpose. It is presumed that the reaction to the active point is insufficient.

 [0054] Specific examples of the organic compound are shown below.

[0055] Phenolic compounds

 (Organic compounds 1-88)

(Organic compound 1)

 (Organic compound 2)

 (Organic compound 3)

 (Organic compound 4)

(Organic compound 5) C (CH ₃ ) ₃

C (CH3) 3

(Organic compound 6)

(Organic compound 7)

(Organic compound 8)

(Organic compound 9)

(Organic compound 10)

(Organic compound 11)

(Organic compound 12)

(Organic compound 13)

 (Organic compound 14)

(Organic compound 17)

(Organic compound 18)

(Organic compound 19)

(Organic compound 20)

(Organic compound 21)

(Organic compound 22)

(Organic compound 23)

HO

(Organic compound 24)

(Organic compound 25)

(Organic compound 26)

(Organic compound 27)

(Organic compound 28)

(Organic compound 29)

(Organic compound 30)

(Organic compound 31)

(Organic compound 33)

(Organic Compound 34)

(Organic compound 35)

(Organic compound 36)

(Organic compound 37)

(Organic compound 38)

(Organic compound 39)

(Organic compound 40)

(Organic compound 41)

(Organic compound 42)

(Organic compound 43)

 (Organic compound 44)

(Organic compound 46)

(Organic compound 47)

(Organic compound 49)

(Organic compound 50)

 (Organic compound 51) α ΟΗ

 OH

(Organic compound 52)

(Organic compound 53)

(Organic compound 54)

(Organic compound 55)

(Organic compound 56)

(Organic compound 57)

(Organic compound 58)

(Organic compound 59)

(Organic compound 60)

(Organic compound 61)

(Organic Compound 62) on

(Organic compound 63)

R = ^C 9 ^H 19

(Organic compound 64)

CH,

(Organic compound 65)

(Organic compound 66)

(Organic compound 67)

(Organic compound 75)

(Organic compound 76)

(Organic compound 77)

(Organic compound 78)

(CH

(Organic compound 79)

(Organic compound 80)

(Organic compound 81)

(Organic compound 82)

(Organic compound 83)

(Organic compound 84)

(Organic compound 85)

(Organic compound 86)

(Organic compound 87)

 (Organic compound 88)

Amine compounds

(Organic compound 89-: 144) (Organic compound 89)

(Organic compound 90)

(Organic compound 91)

(Organic compound 92)

(Organic compound 93) -HN-

R ', RR = C ₇ H ₁₅

(Organic compound 94)

R = C _S H ₁₇ (Organic compound 95)

 R = CgH-ig

(Organic compound 96)

R = C ₁₀ H _2- |

(Organic compound 97)

(Organic compound 98)

(Organic compound 99)

(Organic compound 100)

(Organic compound 101)

(Organic compound 102)

(Organic compound 103)

(Organic compound 104)

(Organic compound 105)

(Organic compound 106)

R = C ₇ H ₁₅ (Organic compound 107)

R = C _S H ₁₇ (Organic compound 108)

R = C ₉ H ₉ (Organic compound 109) α ΝΗ-CH ₂ -CH ₂ -NH- ΗΓΪ し-

(Organic compound 110) r ^^ — NH-CH ₂ -CH ₂ -NH-

(Organic compound 111)

(Organic compound 112)

(Organic compound 113)

(Organic compound 114)

(Organic compound 115)

(Organic compound 116)

(Organic compound 117)

(Organic compound 118)

(Organic compound 119)

(Organic compound 120)

(Organic compound 121) H ₂

(Organic compound 122)

 (Organic compound 123)

CH〇HCH ₃ ) ₂

 (Organic compound 124)

CH ₃

 (Organic compound 125)

(Organic compound 126)

(Organic compounds

 (Organic Compound 128)

(Organic Compound 131)

(Organic Compound 132)

(Organic compound 135)

(Organic compound 136)

(Organic compound 137)

(Organic compound 138)

 (Organic Compound 139)

 (Organic compound 140)

(Organic Compound 141)

R = — N HC ₆ H ₄ N HC ₆ H ₅ , — OC ₆ H ₄ NHC ₆ H ₅ (organic compound 142)

(Organic compound 143)

 (Organic compound 144)

Thiol and thioether compounds

(Organic compounds 145-153)

(Organic compound 145)

(Organic compound 146)

 (Organic compound 147)

(Organic compound 148)

(Organic compound 149)

(Organic compound 150)

(Organic Compound 151)

 (Organic Compound 152)

CH 2-CH 2-COO-12H-| 5 s

 CH 2—CH one-COO-and one H-|

(Organic compound 153)

CH 2-CH 2-COO-¾Η 37 s

 CH 2-CH 2-COO-¾Η 37 Phosphate compounds

(Organic compound 154 160) (Organic compound 154)

(Organic compound 155)

 (Organic compound 156)

1-3 (Organic compound 157)

(Organic compound 158)

(Organic compound 159)

(Organic compound 160)

Phenolic organic compounds

(Organic compound 161)

BEST MODE FOR CARRYING OUT THE INVENTION

 Next, embodiments of the present invention will be described in detail.

(Charging roller configuration)

First, the basic configuration of the contact charging roller of the present invention will be described with reference to FIG. The charging roller 100 according to this embodiment includes a conductive elastic member 102 on the outer periphery of a core metal 101. Layer (simply referred to as a conductive elastic layer or a conductive rubber layer). This charging roller 100 is brought into contact with a photosensitive member (image carrier), and a voltage is applied to the charging roller for photosensitive. body

Charge the (image carrier).

 Such a charging roller system can be either a DC charging system in which a DC voltage is applied to the roller or an induction charging system in which an AC voltage is applied to the roller.

 [0057] The frequency f of the voltage applied in the inductive charging method may be any, but in order to prevent striking, i.e., a striped pattern, the relative speed between the conductive elastic roller and the image carrier member is adjusted. An appropriate frequency can be selected accordingly. The relative speed can be determined by the size of the contact area between the conductive elastic roller and the image carrier.

 [0058] The rubber thread composition that can be used in the conductive rubber layer includes natural rubber, ethylene propylene methylene rubber (EPDM), styrene butadiene rubber (SBR), silicone rubber, urethane rubber, epichlorohydride. Rubber, isoprene rubber (IR), butadiene rubber (BR), nitrile monobutadiene rubber (NBR), chloroprene rubber (CR) and the like. These rubbers can be used alone or as a mixed rubber of two or more.

 [0059] In order to impart conductivity, a conductivity imparting agent is blended with these rubber compositions. Suitable conductivity imparting agents include known carbon black (furnace carbon black or ketjen black), carbon whose ferret diameter is 5 to 300 nm and whose primary particles are 5% or more based on the number. Metal powders such as black and acid tin are listed. The amount of the conductivity-imparting agent used is about 5 to about 50 parts by mass with respect to the total amount of the rubber composition.

[0060] In addition to the rubber base material, the foaming agent, and the conductivity imparting agent, the rubber composition may be blended with a rubber chemical and a rubber additive as necessary to obtain a conductive foamed rubber composition. Rubber chemicals and rubber additives include vulcanizing agents such as sulfur and peroxide, vulcanization accelerating aids such as zinc white and stearic acid, sulfenamide-based, thyrium-based, thiazole-based, darazine-based, etc. Vulcanization accelerators, amine-based, phenol-based, sulfur-based, phosphorus-based anti-aging agents, or acid-detergents, UV absorbers, ozone degradation inhibitors, tackifiers, etc. can be used. Various reinforcing agents, friction coefficient modifiers, and inorganic fillers such as silica, talc, and clay can be arbitrarily selected and used. These conductive rubber layers have a DC volume resistivity in the range of 10 ³ ~: L0 ⁷ Ωcm It is preferable to have.

Further, a release coating layer 103 may be provided outside the conductive elastic layer 102 for the purpose of preventing the toner remaining on the surface of the photoreceptor from adhering to the charging member. The covering layer 103 also prevents the oil from seeping out from the elastic layer 102 and cancels the resistance unevenness of the elastic layer 102 to equalize the resistance. The surface of the charging roller 100 is protected. It performs functions such as adjusting the hardness. Any coating layer may be used as long as it satisfies the above physical properties, or a single layer or a plurality of layers may be used. Examples of the material include resins such as hydrin rubber, urethane rubber, nylon, polyvinylidene fluoride, and polysalt vinylidene. The thickness of the covering layer 103 is preferably 100 to 1000 / ζ πι, and the resistance value is preferably 10 ⁵ to 10 ⁹ Ω′cm. Further, it is preferable that the resistance value increases as it approaches the surface layer. As a method of adjusting the resistance, carbon black, metal, and metal oxide, which are known carbon black for the coating layer, the number average particle diameter of the ferret diameter is 5 to 300 nm, and the primary particles are 5% or more on the number basis. And the like, and the like, and the like.

 [0062] The core metal is not particularly limited, but the diameter is lmn! It is about 10 mm conductive, and metals such as iron, copper, stainless steel, aluminum and nickel can be used as the material. In addition, the surface of these surfaces may be treated to prevent rust and improve scratch resistance.

 [0063] Specific examples and comparative examples will be described below.

 (Manufacture of carbon black)

 (Carbon black # 1)

Carbon black (N220, manufactured by Mitsubishi Chemical Co., Ltd .: Freq diameter number average particle diameter = 210ηm) and 100 parts by weight of the same carbon black with 48 organic compounds (molecular weight = 741, melting point = 125 ° C) 50 parts by weight was added and charged into the twin screw extruder. This twin-screw extruder was mixed with two screws, and PCM-30 (manufactured by Ikegai Seisakusho) was used. It was not modified so that it could be kneaded in a continuous manner, but was modified so that the outlet could be sealed and stirred with two screws. Both were put into the apparatus so that the degree of fullness was 94%, and then stirred while being heated to a first temperature (Tpl) of 160 ° C (melting point + 35 ° C). [0064] Under the stirring conditions, the first stirring speed (Svl) was set at 30 rotations per minute and the first processing time (T1) was set at 10 minutes, and stirring processing was performed. After stirring, the sample was sampled and the state of the grafted soot was confirmed by Soxhlet extraction. It was found that the grafting rate was about 30%. That is, it was confirmed that the grafting progresses on the surface of the carbon black and becomes V.

 [0065] Then, as the stirring conditions of the mixing apparatus, the second stirring speed (Sv2) was set to 50 revolutions per minute at the screw speed, and the second temperature (Tp2) was set to 180 ° C (melting point + 55 ° C). The condition was changed to a condition with higher mechanical shearing force, and the second treatment time (T2) was set to 60 minutes. Thereafter, it was cooled and the treated carbon black was taken out. The organic compound was grafted on the surface of the curve black at a graft ratio of 91%. In addition, 65 number% of primary particles were present. The number average particle diameter of the ferret diameter of carbon black was 42 nm. This carbon black is referred to as “carbon black # 1”.

 [0066] (Carbon black # 2- # 4)

 Carbon black # 2, # 3, and # 4 were obtained in the same manner except that the production conditions for carbon black # 1 were as shown in Tables 1 and 2.

 [0067] (Carbon black # 5)

100% by weight of carbon black (N220, manufactured by Mitsubishi Chemical Co., Ltd.) and 80 parts by weight of organic compound 47 (molecular weight = 784, melting point = 221 ° C) with respect to the carbon black so that the filling degree is 94% The batch type twin-screw extruder used in Example 1 was charged. Subsequently, the mixture was stirred while being heated to 240 ° C. (melting point + 19 ° C.) (Tpl). Stirring was performed at a stirring speed (Svl) of 35 rotations per minute by screw rotation and stirring for 15 minutes (T1). Sampling was performed after the stirring treatment, and when the state of grafting was confirmed by Soxhlet extraction, it was found that the grafting rate was about 32%. That is, it was confirmed that the grafted wrinkles were progressing on the surface. Next, as the stirring conditions, the stirring speed (Sv2) was set to 55 rotations per minute at the number of rotations of the screw, the heating temperature (second temperature Tp2) was set to 270 ° C (melting point + 49 ° C), and the mechanical shearing force was further increased. The condition was changed to a higher one and the treatment was performed for 70 minutes as the treatment time (T2). Thereafter, it was cooled and the treated carbon black was taken out. The organic compound was grafted on the surface with a graft ratio of 72%. In addition, 53 primary particles % Existed. The number average particle diameter of the ferret diameter was 48 nm. This carbon black is called “carbon black # 5”.

[0068] (Carbon black # 6 to # 9)

 Carbon black # 6 to # 9 were obtained in the same manner except that the production conditions for carbon black # 1 were as shown in Tables 1 and 2.

[0069] (Carbon black # 10)

 Carbon black # 1 was replaced with Ravenl035 (Columbia Chemical Industries, Ltd.) instead of carbon black (N220, manufactured by Mitsubishi Chemical Corporation), and the other conditions were the same as shown in Table 1 and Table 2. Obtained carbon black # 10.

[0070] (Carbon black # 11)

 In carbon black # 5, instead of carbon black (N220, manufactured by Mitsubishi Chemical Corporation), Ravenl035 (manufactured by Columbia Chemical Industry Co., Ltd.) was used, and other conditions were the same as shown in Table 1 and Table 2. Obtained carbon black # 11.

[0071] (Carbon black # 12 ~ # 13)

 Carbon black # 12 to # 13 were obtained in the same manner except that the production conditions for carbon black # 1 were as shown in Tables 1 and 2.

[0072] (Carbon black # 14)

 After the surface treatment and grafting process, carbon black (N220, manufactured by Mitsubishi Chemical Corporation) is designated as carbon black # 14.

[0073] (Carbon black # 15)

 In carbon black # 1, the sample was taken out after 1 minute of the first treatment time (T1). This is carbon black # 15.

[0074] (Carbon black # 16)

 In carbon black # 1, the organic compound was treated in the same manner except that it was changed to stearic acid (molecular weight = 284, melting point = 70 ° C.) (comparative compound 1) in which free radicals were not generated. This is carbon black # 16.

Table 3 shows the number average particle diameter of the ferret diameter of carbon black and the number ratio of primary particles in each carbon black # 1 to # 16. [0075] (Carbon black # 17)

 Carbon black # 16 was treated in the same manner except that carbon black was changed to carbon black having a ferret diameter number average particle diameter of 500 m.

 155 parts by mass of this treated carbon black was mixed with 100 parts by mass of carbon black 1 to prepare a carbon black having a number average diameter of 320 m and a primary particle number ratio of 26%. This is carbon black # 17.

 Table 3 shows the number average particle diameter of the ferret diameter of carbon black and the ratio of the number of primary particles in each carbon black # 1 to # 17.

[0076] [Table 1]

[0077] [Table 2] Second stirring speed

Rikiichi Bon Black Organic Compound Processing Time

 (Number of revolutions / min) Fluff ratio Difference from melting point (° C) (min) T2

 Sv2

 1 180 +55 50 60 91

2 190 +65 55 60 93

3 220 +95 60 60 95

4 220 +65 65 60 97

5 270 +49 55 70 72

6 266 +80 60 70 83

7 174 +90 55 40 93

8 265 +70 50 60 94

9 210 +78 50 40 91

10 190 + 6ΰ 60 40 94

11 250 +29 55 40 90

12 180 +55 50 40 65

13 190 +65 55 10 35

14 - - - -

15 ― ― ― 2

16 125 +55 50 30 0

17 125 +55 50 30 0 3] Power of Bon Black-Power of Bon Black-Carbon Black of Bon Black

 Number of average particle size (nm) Average particle size (nm)

1 42 65 25

 2 40 72 25

 3 39 89 25

 4 28 98 25

 5 48 53 28

 6 47 87 28

 7 41 89 28

 8 29 97 28

 9 36 77 28

 10 32 87 2Q

 11 33 83 28

 12 80 35 25

 13 180 7 25

 14 210 0 ―

 15 210 1 Cannot measure

 16 210 0

17 320 15 25 [0079] (Example 1)

First, as a charging roller of Example 1, a charging roller manufactured through the following steps was prepared. First, a stainless steel core metal having a diameter of 4. Omm was placed in a molding die having a cylindrical molding space having a diameter of 6 mm, and a conductive elastic layer forming material was filled in the molding die. Conductive Elastic body layer forming material is 100 parts by mass of styrene-butadiene rubber (SBR), 30 parts by mass of carbon black # 1 as conductivity imparting agent, and 0.5 parts by mass of sulfur as vulcanizing agent. The compounded rubber material was then kneaded using a twin screw extruder (product name: PCM-30, manufactured by Ikegai Co., Ltd.). The conductive elastic layer forming material was filled into a mold, then vulcanized and taken out from the mold to form a layer having a thickness of 1. Omm on the cored bar. The obtained base rubber layer had a volume resistance of 1 × 10 ⁵ Ω′cm.

On the other hand, the releasable coating layer 103 was installed as follows. To 100 parts by mass of epichlorohydrin rubber, 30 parts by mass of titanium oxide for controlling conductivity is added, dispersed using a ball mill, and methyl ethyl ketone as an organic solvent. (MEK) is added, mixed and stirred to prepare a coating solution for forming a releasable coating layer, and this coating solution is applied to the outer peripheral surface of the conductive elastic layer by the dipping method to obtain a layer thickness of 700 / zm. A layer was formed. The obtained releasable coating layer 113 had a volume resistance of 1 × 10 ⁶ Ω′cm.

 [0081] (Examples 2 to 12, Comparative Examples 1 to 5)

 In each of the charging rollers of Examples 2 to 12 and Comparative Examples 1 to 5, carbon black # 1, which is a conductivity imparting agent used for the conductive elastic layer of the charging roller of Example 1, is carbon black.

The same manufacturing method as in Example 1 was adopted except that it was changed to # 2 to # 17. Carbon black # 2 to # 12 are Examples 2 to 12, and carbon black # 13 to # 17 are Comparative Examples 1 to 5.

[0082] (Evaluation)

Each of the charging rollers of Examples 1 to 12 and Comparative Examples 1 and 2 obtained as described above was applied to a printer magicolor 2540 manufactured by Koyo Minolta Business Technologies, Inc., and a solid image was printed on a thin plain paper with a weight of 45 g. Printed. The charging roller core was charged by applying a direct current voltage of 500 (V). The print result was measured using a cherry densitometer (manufactured by Koni Riki Co., Ltd.) for the transmission density light quantity at any 10 points. The results are shown in Table 4.

[0083] [Table 4]

[0084] As understood from Table 4, when the image formation was performed using the charging roller of the example according to the present invention, the solid image was compared with the case where the image formation was performed using the charging roller of the comparative example. As a result, density unevenness was reduced, and improvement in image quality was confirmed.

 Brief Description of Drawings

FIG. 1 is a diagram for explaining the relationship between secondary particles and basic particles.

 FIG. 2 is a view showing a state in which the basic particles constituting the secondary particles are separated from the secondary particles and exist stably.

 FIG. 3 is a diagram illustrating the diameter of a flange used in the present invention.

 FIG. 4 is a cross-sectional view showing a configuration of a charging roller according to an embodiment of the present invention.

 FIG. 5 is a view showing a conventional carbon black aggregate (structure).

Explanation of symbols 100: Developing roller 101: Core

102: conductive elastic layer 103: releasable coating layer

Claims

The scope of the claims

 [1] a support shaft;

 And at least one layer of the resin layer formed on the peripheral surface of the support shaft,

 The resin layer is characterized in that carbon black having a ferret diameter number average particle diameter of 5 to 300 nm and primary particles of 5% or more on a number basis is dispersed in the base resin material. Charging roller.

2. The resin layer according to claim 1, wherein the resin layer includes a plurality of resin layers, and the carbon black is dispersed in at least one resin layer among the plurality of resin layers. Electric roller.

 [3] The plurality of resin layers have a base rubber layer formed on the support shaft, and a surface layer provided on the outer peripheral side from the base rubber layer. Charging roller.

 4. The charging roller according to claim 3, wherein the carbon black is dispersed in the base rubber layer.

 5. The charging roller according to claim 3, wherein the carbon black is dispersed in the surface layer.

 [6] The charging roller according to claim 3, wherein an intermediate layer is provided between the base rubber layer and the surface layer.

7. The charging roller according to claim 6, wherein the carbon black is dispersed in the intermediate layer.

 8. The charging roller according to claim 1, wherein the surface of the carbon black is surface-treated with an organic compound.

9. The charging roller according to claim 8, wherein the organic compound contains at least a phenol compound and / or an amine compound.