WO2014207871A1 - 画像形成装置及びプロセスカートリッジ - Google Patents
画像形成装置及びプロセスカートリッジ Download PDFInfo
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- WO2014207871A1 WO2014207871A1 PCT/JP2013/067712 JP2013067712W WO2014207871A1 WO 2014207871 A1 WO2014207871 A1 WO 2014207871A1 JP 2013067712 W JP2013067712 W JP 2013067712W WO 2014207871 A1 WO2014207871 A1 WO 2014207871A1
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- toner
- particles
- fine particles
- charging member
- mass
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G15/00—Apparatus for electrographic processes using a charge pattern
- G03G15/02—Apparatus for electrographic processes using a charge pattern for laying down a uniform charge, e.g. for sensitising; Corona discharge devices
- G03G15/0208—Apparatus for electrographic processes using a charge pattern for laying down a uniform charge, e.g. for sensitising; Corona discharge devices by contact, friction or induction, e.g. liquid charging apparatus
- G03G15/0216—Apparatus for electrographic processes using a charge pattern for laying down a uniform charge, e.g. for sensitising; Corona discharge devices by contact, friction or induction, e.g. liquid charging apparatus by bringing a charging member into contact with the member to be charged, e.g. roller, brush chargers
- G03G15/0233—Structure, details of the charging member, e.g. chemical composition, surface properties
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G9/00—Developers
- G03G9/08—Developers with toner particles
- G03G9/097—Plasticisers; Charge controlling agents
- G03G9/09708—Inorganic compounds
- G03G9/09716—Inorganic compounds treated with organic compounds
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G9/00—Developers
- G03G9/08—Developers with toner particles
- G03G9/097—Plasticisers; Charge controlling agents
- G03G9/09708—Inorganic compounds
- G03G9/09725—Silicon-oxides; Silicates
Definitions
- the present invention relates to an image forming apparatus and a process cartridge.
- An image forming apparatus employing an electrophotographic system mainly includes an electrophotographic photosensitive member, a charging device, an exposure device, a developing device, a transfer device, a cleaning device, and a fixing device. Steps such as charging, exposure, development, transfer, and cleaning are repeatedly performed.
- the charging device is a device for charging the surface of an electrophotographic photosensitive member (hereinafter also referred to as “photosensitive member”), and a contact charging method using a charging member in contact with the surface of the photosensitive member is often employed.
- a roller-shaped charging member is preferably used.
- toner that has not been transferred to a transfer material such as paper may adhere to the surface of the photoreceptor in the transfer process.
- a cleaning process for example, a cleaning member typified by an elastic blade is brought into contact therewith.
- the residual toner that could not be removed by the cleaning member may affect the next image forming process and cause a phenomenon that the quality of the image is lowered. This phenomenon is generally called cleaning failure. When this phenomenon occurs, the image often appears as a vertical stripe-like image (hereinafter referred to as “vertical stripe image”) on a solid white background.
- Patent Document 1 discloses a charging member that suppresses the occurrence of the above-mentioned cleaning failure by suppressing the fixation of discharge products on the surface of the photoreceptor.
- the image forming apparatus is required to have a higher speed, and at the same time, the use environment of the image forming apparatus is diversified. According to the study by the present inventors, it has been found that an increase in the speed of the image forming apparatus and an image formation in a low-temperature and low-humidity environment increase the stick slip of the cleaning member, and thus easily cause a cleaning failure.
- an object of the present invention is to provide an image forming apparatus that suppresses the generation of a vertical streak image due to the occurrence of cleaning failure, and a process cartridge that is configured to be detachable from the image forming apparatus.
- the present invention relates to a photoconductor, a charging unit for charging the photoconductor with a charging member, an exposure unit for forming an electrostatic latent image on the surface of the charged photoconductor, and an electrostatic latent image.
- An image forming apparatus having a developing unit for supplying toner to the formed photoconductor to form a toner image on the surface of the photoconductor, and a cleaning unit for collecting residual toner before the charging unit
- the charging member has a conductive substrate and a conductive resin layer,
- the conductive resin layer includes a binder resin C and bowl-shaped resin particles,
- the surface of the charging member has a concave portion derived from the opening of the bowl-shaped resin particles and a convex portion derived from the opening edge of the bowl-shaped resin particles,
- the toner is a toner containing toner particles containing a binder resin T and a colorant, and inorganic fine particles, The inorganic fine particles are silica fine particles;
- the silica fine particles are treated with 15.0 parts by mass or more and 40.0 parts by mass or less of silicone oil with respect to 100 parts by mass of the silica raw material, and the carbon oil-based immobilization ratio (%) of the silicone oil. Is 70% or more, and the coverage X1 with the silica fine particles on the surface of the toner determined by an X-ray photoelectron spectrometer (ESCA) is 50.0 area% or more and 75.0 area% or less, and the silica fine particles
- ESA X-ray photoelectron spectrometer
- the present invention relates to an image forming apparatus characterized in that when the theoretical coverage by X is X2, the diffusion index represented by the following formula 1 is a toner that satisfies the following formula 2.
- Diffusion index X1 / X2
- compression 2 Diffusion index ⁇ ⁇ 0.0042 ⁇ X1 + 0.62
- the occurrence of a cleaning defect can be suppressed, and the occurrence of vertical streak images due to the occurrence of the cleaning defect can be suppressed.
- FIG. 1 is a schematic cross-sectional view of an aspect of an image forming apparatus according to the present invention. It is a figure showing an example of the load displacement curve in the charging member which concerns on this invention.
- FIG. 3 is an enlarged view of the vicinity of a contact portion between a charging member and an electrophotographic photosensitive member according to the present invention.
- FIG. 4 is a diagram illustrating a boundary line of a diffusion index of toner according to the present invention.
- FIG. 5 is a graph plotting a coverage ratio X1 and a diffusion index of toner according to the present invention.
- mode of the mixing processing apparatus which can be used for the external addition mixing of the inorganic fine particle which concerns on this invention.
- mode of the structure of the stirring member used for the mixing processing apparatus which concerns on this invention.
- the inventors of the present invention have intensively studied a mechanism that exerts an effect of suppressing the occurrence of defective cleaning in the image forming apparatus or process cartridge using the charging member and toner as described above. As an example, a detailed description will be given below based on the results of investigation using a blade-shaped cleaning member.
- the inventors of the present invention observed in detail the surface of the cleaning member in contact with the photosensitive member when the cleaning failure occurred. As a result, it was observed that local vibrations, that is, fine stick slips occurred at several locations in the longitudinal position of the cleaning member, and toner slipped from the locations where the stick slips occurred. At the same time, it was also found that the stick-slip is likely to occur where the aggregated residual toner collides with the cleaning member.
- the present inventors observed the behavior of the surface of the cleaning member when no residual toner was present.
- a conventional charging member described in Patent Document 1 was used to charge the photosensitive member, and the photosensitive member was gradually rotated at a high speed.
- the speed of rotation of the photoconductor increased, the number of stick-slip occurrence locations on the surface of the cleaning member increased, and at the same time, it was confirmed that the slip distance increased.
- the present inventors prepared toner that has undergone a transfer process using an image forming apparatus to which toner has conventionally been applied. That is, the above toner was separately prepared as an aggregated toner that simulated the residual toner (hereinafter, also referred to as “aggregated toner”). Then, the agglomerated toner was supplied to the cleaning member in contact with the photoconductor rotated at a high speed. As a result, the toner slipped from the place where the stick slip occurred, and a toner streak was formed on the surface of the photoreceptor after passing through the cleaning member. Further, when the rotation was continued, the portion where the stick slip occurred was enlarged, and the toner streak increased.
- the charging member according to the present invention was used in place of the conventional charging member, and the surface of the cleaning member was first observed in the absence of the agglomerated toner.
- the stick-slip observed with the conventional charging member could not be confirmed.
- the agglomerated toner was supplied to the cleaning member in the same manner as described above, no toner streak occurred immediately after the supply, but a short time after the supply, toner streak occurred.
- the present inventors conducted the above investigation using the toner according to the present invention.
- the residual toner was simulated to be reproduced in the same manner as the above aggregated toner, it was found that the toner according to the present invention hardly forms the aggregated toner even after the transfer process.
- a toner according to the present invention having undergone a transfer process was prepared.
- the photosensitive member was rotated at high speed while being charged by the charging member according to the present invention.
- the toner according to the present invention after the transfer process was supplied to the cleaning member.
- the stick-slip was not confirmed, and toner streaks could not be confirmed.
- the inventors presume a mechanism that can suppress a cleaning failure by using the charging member according to the present invention and the toner according to the present invention as follows.
- the charging member surface according to the present invention includes “a concave portion derived from the opening of the bowl-shaped resin particles” and “a convex portion derived from the edge of the opening of the bowl-shaped resin particles”.
- the convex portion derived from the opening comes into contact with the photosensitive member, and the concave portion has a space between the photosensitive member and the photosensitive member.
- the convex portion can be elastically deformed as shown in FIG.
- the charging member absorbs the vibration that increases as the photoconductor rotates at a high speed and stabilizes the photoconductor at a high speed, thereby suppressing the occurrence of local stick slip of the cleaning member. ing.
- the agglomerated toner that has undergone the transfer process is often in a dense state and at the same time, is often given a large electric field, and has a high adhesion to the surface of the photoreceptor. That is, the releasability from the photoreceptor is small.
- Such an agglomerated toner imparts a physical impact force when the cleaning member collides. It is presumed that when the aggregated toner comes to the place where the stick slip is generated, the stick slip increases due to the physical impact, and a cleaning failure is induced.
- the cleaning member in which vibration that causes stick-slip generation is suppressed by the charging member according to the present invention can remove the aggregated toner from the surface of the photoreceptor, and no cleaning failure occurs immediately after the aggregated toner is supplied. .
- the aggregated toner that has been removed often remains on the surface of the cleaning member, and the aggregated toners that come from one to the next repeatedly accumulate and reaggregate near the surface of the cleaning member.
- the accumulated and re-aggregated toner has a further increased adhesive force with the surface of the photoreceptor, and is easily caught on the surface of the photoreceptor. It is speculated that the accumulated and re-aggregated toner induces stick-slip of the cleaning member and causes a cleaning defect with time.
- the toner according to the present invention precisely controls the state of the silica fine particles on the toner surface and greatly reduces the cohesiveness between the toners.
- the generation of aggregated toner after the transfer process and the accumulation / reaggregation of toner near the surface of the cleaning member are greatly reduced.
- the toner whose cohesion is controlled is combined with a cleaning member in which vibration that causes stick-slip is suppressed by the charging member. It is suppressed.
- good cleaning performance can be maintained continuously even when the photosensitive member is rotated at a high speed.
- a photoconductor 401 shown in FIG. 15 is obtained by forming an ITO film having a thickness of 5 ⁇ m on the surface of a glass drum, and further forming a charge transport layer used for the photoconductor on the outer periphery thereof to a thickness of 17 ⁇ m.
- the charging member 5 and the cleaning member 10 were brought into contact with the photosensitive member, and observation was performed from the opposite side of the cleaning member 10 using a high-speed camera.
- the discussion on the suppression of the generation of aggregated toner by precisely controlling the silica fine particle state on the toner surface will be described in detail later.
- the agglomerated toner that has passed through the cleaning member has a high adhesive force, so that it easily adheres to the surface of the charging member and affects the charging process. This is generally referred to as charging member contamination.
- charging member contamination When the charging member contamination progresses, abnormal discharge due to the contamination is caused. When this phenomenon occurs, it often appears as a dot-like image (hereinafter also referred to as “dot image”) on the halftone image.
- the present inventors have found that the agglomerated toner easily adheres to the charging surface, and at the same time, reduces the follower rotation of the charging member. It was found that minute slips are likely to occur.
- the portion where the agglomerated toner is fixed to the surface of the charging member is likely to be caught on the photosensitive member as compared with the portion where the toner is not fixed.
- the fixed portion generates a minute distortion on the surface of the charging member when the contact state between the charging member and the photosensitive member is released, and generates a minute slip when the distortion is released. Then, the aggregated toner is further rubbed by the minute slip. Thereby, it can be inferred that the adhesion is further expanded and the charging member is further soiled.
- the charging member according to the present invention has a convex portion derived from the edge of the opening of the bowl-shaped resin particles, and the convex portion comes into contact with the photosensitive member. In this case, the ease of being caught with the photoconductor is controlled by the convex portion.
- the toner according to the present invention contains a considerable amount of toner and inorganic fine particles (hereinafter also referred to as “toner component”) that have passed through the cleaning member.
- toner component inorganic fine particles
- the toner component once adheres to the convex portion of the charging member according to the present invention, a minute slip does not occur when the contact is released, and no increase in toner fixation is observed.
- the present inventors presume the occurrence mechanism of the above phenomenon as follows.
- the toner according to the present invention precisely controls the state of the silica fine particles on the surface of the toner.
- silicone oil is fixed on the surface of the inorganic fine particles, and the coverage with respect to the toner particles is regulated.
- the toner component generated from such toner does not adhere to the convex portion of the charging member according to the present invention, but only adheres once.
- the toner component according to the present invention once adhered to the convex portion plays a role as a spacer between the charging member according to the present invention and the photosensitive member. As a result, it is presumed that a minute slip between the photosensitive member and the charging member can be suppressed, and at the same time, a stable driven rotational property can be maintained even at a higher speed.
- the charging member according to the present invention has an irregular shape derived from bowl-shaped resin particles, and at the same time, elastically deforms when abutting with the photosensitive member, and at the same time when the abutting is released, the elastic deformation is released due to the reaction. .
- the toner component adhering to the convex portion is easily separated from the convex portion due to a force (hereinafter also referred to as “restoring force”) for returning the deformation to the original.
- restoring force a force for returning the deformation to the original.
- This phenomenon suppresses the toner component from sticking to the convex portion of the charging member.
- new toner components sequentially adhere to the surface of the charging member, and it is assumed that the above-described minute slip suppression and driven rotation stabilization can be achieved.
- the charging member according to the present invention suppresses stick-slip of the cleaning member, and the toner according to the present invention greatly reduces the cohesiveness between the toners.
- the toner according to the present invention with the charging member according to the present invention, the effect of suppressing the occurrence of local stick slip of the cleaning member can be remarkably enhanced. Thereby, generation
- the stick-slip of the cleaning member can be uniformly supplied to the surface of the charging member with the toner component that has passed through the cleaning process.
- the adhesion of the toner component to the surface of the charging member according to the present invention that can be elastically deformed, a minute slip of the charging member is remarkably suppressed, and at the same time, the driven rotational stability is remarkably improved. . Thereby, the contamination of the charging member can be suppressed.
- the present inventors speculate that the improvement in the stability of the driven rotation further enhances the stick-slip suppression effect of the cleaning member.
- Toner> The present inventors consider that the following four points are necessary as toner conditions for achieving the prevention of the occurrence of defective cleaning and the prevention of contamination of the charging member.
- Inorganic fine particles (hereinafter also referred to as “external additives”) on the surface of the toner are difficult to be embedded in the toner. If the external additive is embedded in the toner, the following releasability of the toner applied by the external additive and the spacer effect described above cannot be expressed.
- Toner releasability As a result, the generation of the agglomerated toner can be suppressed, and at the same time, the toner component can be prevented from sticking to the surface of the charging member.
- the inventors of the present invention specify the surface properties of the silica fine particles, which are external additives according to the present invention, and at the same time, the silica fine particles existing on the toner surface. It came to stipulate the condition.
- the “surface properties of silica fine particles” are defined as follows.
- the toner according to the present invention contains toner particles containing a binder resin and a colorant, and inorganic fine particles.
- the binder resin contained in the toner particles is also referred to as a binder resin T.
- the inorganic fine particles are silica fine particles
- the toner contains 0.40 parts by mass or more and 1.50 parts by mass or less of the silica fine particles per 100 parts by mass of the toner particles.
- the silica fine particles are contained in an amount of 0.50 to 1.30 parts by mass per 100 parts by mass of the toner particles.
- the releasability of the toner can be improved, and at the same time, the embedding of the toner in the external additive can be suppressed. As a result, it is possible to suppress the occurrence of defective cleaning and at the same time suppress the contamination of the charging member.
- the silica fine particles are treated with 15.0 parts by mass or more and 40.0 parts by mass or less of silicone oil based on 100 parts by mass of the silica base material, and the silicone oil is fixed on the basis of carbon amount.
- the rate (%) is 70% or more.
- the carbon-based immobilization rate of silicone oil corresponds to the amount of silicone oil molecules chemically bonded to the surface of the silica base.
- the cohesiveness and friction coefficient between the silica fine particles can be controlled to the ranges necessary for the present invention by controlling the number of treatment parts and the immobilization ratio with the silicone oil within the above ranges. Further, the same properties can be imparted to the toner to which the silica fine particles are externally added, and the effect (2) can be easily improved.
- the present inventors presume the effect expression mechanism as follows.
- the present invention is characterized by silica fine particles having a relatively large number of silicone oil-treated parts and a high immobilization rate. Such silica fine particles can increase the coefficient of friction without deteriorating the cohesiveness between the silica fine particles.
- the present inventors consider that the deterioration of cohesiveness can be reduced by fixing the terminal of the silicone oil molecule to the surface of the silica base material. Thereby, generation
- the toner according to the present invention is a toner in which the coefficient of friction between the toners is increased without deteriorating the cohesiveness between the toners. This makes it possible to obtain the effects (2) and (3) at the same time.
- the number of parts of the silica fine particles treated with silicone oil is more preferably 17.0 parts by mass or more and 30.0 parts by mass or less with respect to 100 parts by mass of the silica raw material.
- the conversion rate (%) is more preferably 90% or more. Thereby, expression of the effect mentioned above can be raised more.
- the toner according to the present invention defines the “external addition state of silica fine particles” as follows.
- the coverage X1 with silica fine particles on the surface of the toner obtained by an X-ray photoelectron spectrometer is 50.0 area% or more and 75.0 area% or less.
- the toner used in the present invention is characterized in that the diffusion index represented by the following formula 1 satisfies the following formula 2 when the theoretical coverage by silica fine particles is X2.
- Diffusion index X1 / X2 (Expression 2) Diffusion index ⁇ ⁇ 0.0042 ⁇ X1 + 0.62
- the coverage X1 can be calculated from the ratio of the Si element detection intensity when the toner is measured to the Si element detection intensity when the silica fine particle is measured by ESCA.
- the coverage X1 indicates the ratio of the area actually covered with the silica fine particles on the surface of the toner particles.
- the coverage X1 is 50.0 area% or more and 75.0 area% or less, the fluidity and chargeability of the toner can be controlled to be in a good state through the durability test.
- the coverage X1 is less than 50.0 area%, it is not possible to obtain sufficient ease of toner loosening described later. For this reason, under severe evaluation conditions as described above, the fluidity is deteriorated due to the deterioration of the toner, the releasability from the developing member is insufficient, and the problem of leaving the durability cannot be improved.
- the theoretical coverage X2 by the silica fine particles is calculated from the following formula 4 using the number of parts by mass of the silica fine particles per 100 parts by mass of the toner particles, the particle size of the silica fine particles, and the like. This indicates the ratio of the area that can theoretically cover the toner particle surface.
- Diffusion index indicates the difference between the actual coverage X1 and the theoretical coverage X2.
- the degree of this divergence is considered to indicate the number of silica fine particles laminated in two and three layers in the vertical direction from the toner particle surface.
- the diffusion index is 1, but this is a case where the coverage ratio X1 coincides with the theoretical coverage ratio X2, and there is no state where there are no two or more layers of silica fine particles.
- silica fine particles are present on the toner surface as aggregated secondary particles, a difference between the actually measured coverage and the theoretical coverage is generated, and the diffusion index is lowered.
- the diffusion index can be paraphrased as indicating the amount of silica fine particles present as secondary particles.
- the diffusion index is in the range represented by the above formula 2, and it is considered that this range is larger than that of the toner manufactured by the conventional technique.
- a large diffusion index indicates that the amount of silica fine particles on the surface of the toner particles is small as secondary particles and is large as primary particles.
- the upper limit of the diffusion index is 1.
- the present inventors have found that when the coverage ratio X1 and the diffusion index satisfy the range represented by Formula 2 at the same time, the ease of toner loosening during pressurization can be greatly improved.
- the present inventors presume the reason why the ease of toner loosening is improved when the coverage X1 and the diffusion index satisfy the range represented by Formula 2 at the same time. It is considered that when toner is present in a narrow and high pressure place such as a blade nip, the toner tends to be in a state of “meshing” so that external additives existing on the surface do not collide with each other. . At this time, if there are many silica fine particles present as secondary particles, the influence of meshing becomes too great, and it becomes difficult to loosen the toners quickly.
- silica fine particles existing as primary particles are buried in the surface of the toner particles, and the fluidity of the toner is lowered. At that time, it is presumed that the influence of meshing between silica fine particles existing as secondary particles that are not buried becomes large, and hinders the ease of loosening of the toner.
- the toner according to the present invention since many silica fine particles are present as primary particles, even when the toner is deteriorated, it is difficult for the toner to bite between the toners, and even when the toner is rubbed in the transfer process or the like. , Very easy to break into each grain. That is, it has become possible to dramatically improve the “easy to loosen toner” described in the above (4), which was difficult only by the conventional control of the coverage X1.
- the present inventors have found that when the coverage ratio X1 and the diffusion index satisfy the range represented by Formula 2 at the same time, the degree of progress of toner deterioration is greatly reduced.
- the reason for this is that when the silica particles on the surface of the toner particles are present as primary particles, even if the toners are in contact with each other, the possibility that the silica particles are in contact with each other is reduced, and the pressure applied to the silica particles is reduced. This is presumed to be due. That is, the effect (1) described above can be obtained.
- the boundary line of the diffusion index in the present invention is a function with the coverage X1 as a variable in the range where the coverage X1 is 50.0 area% or more and 75.0 area% or less.
- the calculation of this function was obtained empirically from the phenomenon that the toner is sufficiently easily loosened when pressurized when obtaining the coverage X1 and the diffusion index by changing the silica fine particles, external addition conditions and the like. .
- the stick slip of the cleaning member can be suppressed by controlling the ease of toner loosening, it is possible to suppress the occurrence of defective cleaning.
- the minute slip of the charging member according to the present invention is suppressed and the driven rotation is stabilized, contamination of the charging member can be suppressed.
- FIG. 11 is a graph plotting the relationship between the coverage ratio X1 and the diffusion index by producing a toner in which the coverage ratio X1 is arbitrarily changed by changing the amount of silica fine particles to be added using three types of external additive mixing conditions. It is. Of the toners plotted in this graph, it was found that the toner plotted in the region satisfying the expression 2 sufficiently improves the ease of loosening during pressurization.
- the boundary line of the diffusion index is considered to be a function with the coverage X1 as a variable. That is, there was a correlation between the coverage X1 and the diffusion index, and it was experimentally determined that it is important to control the diffusion index according to the coverage X1.
- the present inventors consider that the above (1) to (4) are necessary as toner conditions for suppressing the occurrence of poor cleaning and suppressing the contamination of the charging member. .
- the toner according to the present invention exhibits the above characteristics (1) to (4) due to a synergistic effect by controlling both “surface properties of silica fine particles” and “external addition state of silica fine particles”. I guess it can be solved for the first time.
- the toner according to the present invention contains a colorant.
- Examples of the colorant preferably used in the present invention include the following.
- organic pigments or organic dyes as cyan colorants include copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, and basic dye lake compounds.
- organic pigments or organic dyes as magenta colorants include the following. Condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, perylene compounds.
- organic pigments or organic dyes as yellow colorants include compounds represented by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds.
- black colorant examples include carbon black, the above-described yellow colorant, magenta colorant, and cyan colorant that are toned to black.
- a colorant When using a colorant, it is preferably used by adding 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the polymerizable monomer or the binder resin T.
- the toner according to the present invention can contain a magnetic material.
- the magnetic material can also serve as a colorant.
- the magnetic material used in the present invention is mainly composed of triiron tetroxide or ⁇ -iron oxide, and may contain elements such as phosphorus, cobalt, nickel, copper, magnesium, manganese, and aluminum.
- the shape of the magnetic material includes a polyhedron, octahedron, hexahedron, sphere, needle shape, flake shape, etc., but a polyhedron, octahedron, hexahedron, sphere and the like having a small anisotropy can reduce the image density. It is preferable in terms of enhancement.
- the content of the magnetic substance in the present invention is preferably 50 parts by mass or more and 150 parts by mass or less with respect to 100 parts by mass of the polymerizable monomer or the binder resin T.
- the toner according to the present invention preferably contains a wax.
- the wax preferably includes a hydrocarbon wax.
- Other waxes include the following. Amide waxes, higher fatty acids, long chain alcohols, ketone waxes, ester waxes, and derivatives such as these graft compounds and block compounds. If necessary, two or more kinds of waxes may be used in combination. Among these, when the hydrocarbon wax by the Fischer-Tropsch method is used, the high temperature offset resistance can be kept good while maintaining the developability well for a long time.
- These hydrocarbon waxes may contain an antioxidant within a range that does not affect the chargeability of the toner.
- the content of the wax is preferably 4.0 parts by mass or more and 30.0 parts by mass or less, more preferably 16.0 parts by mass or more and 28.0 parts by mass or less with respect to 100 parts by mass of the binder resin T. is there.
- a charge control agent can be contained in the toner particles as necessary. By blending the charge control agent, the charge characteristics can be stabilized and the optimum triboelectric charge amount can be controlled according to the development system.
- the charge control agent As the charge control agent, a known one can be used, and a charge control agent that has a high charging speed and can stably maintain a constant charge amount is particularly preferable. Further, when the toner particles are produced by a direct polymerization method, a charge control agent having a low polymerization inhibition property and substantially free from a solubilized product in an aqueous medium is particularly preferable.
- the toner according to the present invention may contain these charge control agents alone or in combination of two or more.
- the blending amount of the charge control agent is preferably 0.3 parts by mass or more and 10.0 parts by mass or less, more preferably 0.5 parts by mass with respect to 100 parts by mass of the polymerizable monomer or binder resin T.
- the amount is 8.0 parts by mass or more.
- the toner according to the present invention contains toner particles and inorganic fine particles.
- the inorganic fine particles are silica fine particles.
- the silica fine particles used in the present invention are produced by hydrophobizing with 15.0 parts by mass or more and 40.0 parts by mass or less of silicone oil with respect to 100 parts by mass of the silica raw material.
- the degree of the hydrophobization treatment is preferably 70% or more, more preferably 80% or more, as measured by a methanol titration test from the viewpoint of suppressing the decrease in chargeability in a high-temperature and high-humidity environment.
- silicone oil examples include dimethyl silicone oil, methylphenyl silicone oil, ⁇ -methylstyrene modified silicone oil, chlorophenyl silicone oil, and fluorine modified silicone oil.
- the kinematic viscosity at 25 ° C. of the silicone oil used for the treatment of the silica fine particles is preferably 30 cSt or more and 500 cSt or less.
- the kinematic viscosity of the silicone oil is closely related to the molecular chain length of the silicone oil, and when the kinematic viscosity is in the above range, it is preferable because the aggregation degree of the silica fine particles can be easily controlled in a suitable range.
- silicone oil is 40 cSt or more and 300 cSt or less.
- the apparatus for measuring the kinematic viscosity of silicone oil include a capillary type kinematic viscometer (manufactured by Kashiwagi Scientific Instruments Co., Ltd.) or a fully automatic microkinematic viscometer (manufactured by Viscotech Co., Ltd.).
- the silica fine particles used in the present invention are preferably those obtained by treating the silica raw material with silicone oil and then treating with at least one of alkoxysilane and silazane.
- the surface of the silica base material that could not be hydrophobized with silicone oil can be hydrophobized, so that highly hydrophobized silica fine particles can be obtained stably.
- the present inventors consider as follows. Of the silicone oil molecule ends on the surface of the silica fine particles, only one end has a degree of freedom, which affects the cohesiveness between the silica fine particles.
- the silicone oil molecular terminal is hardly present on the outermost surface of the silica fine particles, so that the cohesiveness of the silica fine particles can be further reduced.
- the cohesiveness between the toners when externally added can be greatly reduced, and the ease of toner loosening can be improved.
- the silica base material is, for example, so-called wet silica produced by vapor phase oxidation of silicon halide, so-called dry process or dry silica called fumed silica, and water glass. Both can be used.
- the silica fine particles used in the present invention may be crushed during the above treatment step or after the treatment step. Furthermore, when performing a two-stage process, it is also possible to perform a crushing process between processes.
- the surface treatment with silicone oil and the surface treatment with alkoxysilane and silazane may be either dry treatment or wet treatment.
- the specific procedure of the surface treatment with the silicone oil of the silica raw material is, for example, by reacting the silica fine particles in a solvent (preferably adjusted to pH 4 with an organic acid or the like) in which the silicone oil is dissolved. Remove. Thereafter, crushing treatment may be performed.
- a solvent preferably adjusted to pH 4 with an organic acid or the like
- the specific procedure for performing the surface treatment with at least one of alkoxysilane and silazane is as follows.
- crushed silicone oil-treated silica fine particles are placed and reacted, and then the solvent is removed and crushed.
- the following method may be used.
- silica fine particles are put into a reaction vessel.
- alcohol water is added with stirring in a nitrogen atmosphere
- silicone oil is introduced into the reaction tank to perform surface treatment
- the mixture is further heated and stirred to remove the solvent, followed by crushing treatment.
- the surface treatment with at least one of alkoxysilane and silazane the surface treatment is performed by introducing at least one of alkoxysilane and silazane while stirring in a nitrogen atmosphere, and further, the mixture is heated and stirred to remove the solvent and then cooled.
- alkoxysilane examples include methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, and phenyltriethoxysilane.
- hexamethyldisilazane can be preferably exemplified as silazane.
- the amount of treatment with at least one of these alkoxysilanes and silazanes is 0.1 parts by mass or more and 20.0 parts by mass or less as a total amount of at least one of alkoxysilane and silazane with respect to 100 parts by mass of the silica raw material.
- a method of performing a heat treatment for the reaction of silicone oil in the process of obtaining silica fine particles can be suitably exemplified.
- the heat treatment temperature is preferably 100 ° C. or higher. The higher the heat treatment temperature, the higher the immobilization rate.
- This heat treatment step is preferably performed immediately after the silicone oil treatment, but when the crushing treatment is performed, the heat treatment step may be performed after the crushing treatment step.
- the silica fine particles used in the present invention preferably have an apparent density of 15 g / L or more and 50 g / L or less.
- the apparent density of the silica fine particles being in the above range indicates that the silica fine particles are difficult to be densely packed and exist with a lot of air between the fine particles, and the apparent density is very low. For this reason, even in the toner, since the toner is less likely to be clogged closely, the deterioration rate can be significantly reduced.
- a more preferable range is 18 g / L or more and 45 g / L or less.
- Examples of means for controlling the apparent density of the silica fine particles within the above range include adjusting the particle size of the silica raw material used for the silica fine particles, the presence / absence and the strength of the above-mentioned crushing treatment, and the treatment amount of the silicone oil. .
- the particle size of the silica raw material By reducing the particle size of the silica raw material, the BET specific surface area of the silica fine particles to be obtained becomes large and a large amount of air can be interposed, so that the apparent density can be reduced.
- By performing the crushing treatment relatively large secondary particles contained in the silica fine particles can be loosened into relatively small secondary particles, and the apparent density can be reduced.
- the silica base material used in the present invention has a specific surface area (BET specific surface area) measured by a BET method by nitrogen adsorption of 130 m 2 / g or more and 330 m 2 / g or less in order to impart good fluidity to the toner. Is preferred. In the case of this range, the fluidity and chargeability imparted to the toner are easily secured through durability.
- the BET specific surface area of the silica base material is more preferably 200 m 2 / g or more and 320 m 2 / g or less.
- the measurement of the specific surface area (BET specific surface area) measured by the BET method by nitrogen adsorption is performed according to JISZ8830 (2001).
- the measuring apparatus an “automatic specific surface area / pore distribution measuring apparatus, TriStar 3000 (manufactured by Shimadzu Corporation)” which employs a gas adsorption method based on a constant volume method as a measuring method is used.
- the number average particle diameter of the primary particles of the silica base material used in the present invention is preferably 3 nm or more and 50 nm or less, and more preferably 5 nm or more and 40 nm or less.
- the toner according to the present invention preferably has a weight average particle diameter (D4) of 5.0 ⁇ m or more and 10.0 ⁇ m or less, more preferably 5.5 ⁇ m or more, 9 from the viewpoint of a balance between developability and fixability. .5 ⁇ m or less.
- D4 weight average particle diameter
- the average circularity of the toner particles is preferably 0.960 or more, and more preferably 0.970 or more.
- the shape of the toner is a sphere or a shape close to this, and it is easy to obtain a uniform triboelectric chargeability with excellent fluidity. Therefore, it is preferable because high developability can be easily maintained even in the latter half of the durability.
- toner particles having a high average circularity are preferable because the coverage X1 and the diffusion index can be easily controlled within the scope of the present invention in the external addition treatment of inorganic fine particles described later. Further, from the viewpoint of ease of loosening of the toner at the time of pressurization, it is preferable because the meshing effect on the surface shape of the toner particles hardly occurs and the ease of loosening can be further improved.
- the toner according to the present invention can adjust the number of silica fine particles treated with silicone oil, the carbon oil-based immobilization rate of silicone oil, the coverage X1, and the diffusion index. If it is a manufacturing method which has the process of adjusting an average circularity preferably, in other manufacturing processes, it will not specifically limit, It can manufacture by a well-known method.
- the binder resin T, the colorant, and other additives such as a release agent as necessary are sufficiently mixed by a mixer such as a Henschel mixer or a ball mill.
- a mixer such as a Henschel mixer or a ball mill.
- the toner material is dispersed or dissolved by using a heat kneader such as a heating roll, a kneader, and an extruder to disperse or dissolve the toner material.
- pulverization, classification, and if necessary, surface treatment is performed to obtain toner particles. obtain. Either the classification or the surface treatment may be performed first. In the classification step, it is preferable to use a multi-division classifier in terms of production efficiency.
- the above pulverization can be performed by a method using a mechanical impact type or jet type known pulverizer.
- a mechanical impact type or jet type known pulverizer in order to obtain a toner having a preferable circularity, it is preferable to further pulverize by applying heat or to add a mechanical impact force supplementarily.
- a hot water bath method in which finely pulverized (classified as necessary) toner particles are dispersed in hot water, or a method of passing through a hot air stream may be used.
- Examples of means for applying a mechanical impact force include a method using a mechanical impact type pulverizer such as a kryptron system manufactured by Kawasaki Heavy Industries, Ltd. or a turbo mill manufactured by Turbo Industry. Further, there is a method of applying a mechanical impact force to the toner by a compressive force or a frictional force, such as a mechano-fusion system manufactured by Hosokawa Micron Corporation or a hybridization system device manufactured by Nara Machinery Co., Ltd.
- the toner particles used in the present invention are preferably those produced in an aqueous medium such as a dispersion polymerization method, an association aggregation method, a dissolution suspension method, and a suspension polymerization method. More preferably.
- the suspension polymerization method is a method in which a polymerizable monomer and a colorant, and other additives such as a polymerization initiator, a crosslinking agent, and a charge control agent are uniformly dissolved or dispersed as necessary.
- a meter composition is obtained.
- the polymerizable monomer composition is dispersed in a continuous layer (for example, an aqueous phase) containing a dispersion stabilizer using a suitable stirrer, and then the polymerizable monomer in the polymerizable monomer composition is used.
- the toner is polymerized to obtain toner particles having a desired particle size.
- the toner particles obtained by this suspension polymerization method (hereinafter also referred to as “polymerized toner particles”) have a substantially spherical shape, and therefore satisfy a predetermined average circularity and have a charge amount of This is preferable because the distribution is relatively uniform.
- polymerizable monomer constituting the polymerizable monomer composition.
- styrene or a styrene derivative is preferably used alone or mixed with another polymerizable monomer from the viewpoint of the development characteristics and durability of the toner.
- the polymerization initiator used in the suspension polymerization method preferably has a half-life of 0.5 hours or more and 30.0 hours or less during the polymerization reaction. Moreover, it is preferable that the addition amount of a polymerization initiator is 0.5 to 20.0 mass parts with respect to 100 mass parts of polymerizable monomers.
- polymerization initiator examples include azo or diazo polymerization initiators and peroxide polymerization initiators.
- a crosslinking agent may be added during the polymerization reaction, and a preferable addition amount is 0.1 parts by mass or more and 10.0 parts by mass or less with respect to 100 parts by mass of the polymerizable monomer.
- a cross-linking agent a compound having two or more polymerizable double bonds is mainly used.
- an aromatic divinyl compound, a carboxylic acid ester having two double bonds, a divinyl compound, and a compound having three or more vinyl groups are used alone or as a mixture of two or more.
- the production of toner particles by the suspension polymerization method will be specifically described, but the present invention is not limited to this.
- a disperser such as a homogenizer, a ball mill, or an ultrasonic disperser is dispersed.
- a disperser such as a homogenizer, a ball mill, or an ultrasonic disperser is dispersed.
- the particle size of the obtained toner particles becomes sharper by using a disperser such as a high-speed stirrer or an ultrasonic disperser to obtain a desired toner particle size all at once.
- the polymerization initiator may be added at the same time as other additives are added to the polymerizable monomer, or may be mixed immediately before being suspended in the aqueous medium. Also, a polymerization initiator dissolved in a polymerizable monomer or solvent can be added immediately after granulation and before starting the polymerization reaction.
- stirring may be performed using a normal stirrer to such an extent that the particle state is maintained and the floating and settling of particles is prevented.
- dispersion stabilizer known surfactants, organic dispersants or inorganic dispersants can be used.
- inorganic dispersants are less likely to produce harmful ultrafine powders, and because of their steric hindrance, dispersion stability is obtained, so that stability is not easily lost even when the reaction temperature is changed, and cleaning is easy and adversely affects the toner. Since it is difficult, it can be preferably used.
- inorganic dispersing agents include tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, phosphate polyvalent metal salts such as hydroxyapatite; carbonates such as calcium carbonate and magnesium carbonate, calcium metasuccinate, calcium sulfate, sulfuric acid Inorganic salts such as barium; inorganic compounds such as calcium hydroxide, magnesium hydroxide and aluminum hydroxide.
- inorganic dispersants are preferably used in an amount of 0.20 parts by mass or more and 20.00 parts by mass or less with respect to 100 parts by mass of the polymerizable monomer.
- the said dispersion stabilizer may be used independently and may use multiple types together. Furthermore, you may use together 0.0001 mass part or more and 0.1000 mass part or less surfactant with respect to 100 mass parts of polymerizable monomers.
- the polymerization temperature is set to 40 ° C or higher, generally 50 ° C to 90 ° C.
- the toner according to the present invention is obtained by externally adding silica fine particles, which are inorganic fine particles, to the toner particles and adhering them to the surface of the toner particles. It is also possible to add a classification step to the production process (before mixing the inorganic fine particles) to remove coarse powder and fine powder contained in the toner particles.
- particles having a primary particle number average particle diameter (D1) of 80 nm or more and 3 ⁇ m or less may be added.
- lubricants such as fluororesin powder, zinc stearate powder and polyvinylidene fluoride powder; abrasives such as cerium oxide powder, silicon carbide powder and strontium titanate powder; spacer particles such as silica affect the effect of the present invention. A small amount can be used.
- the mixing processing apparatus for externally mixing the silica fine particles a known mixing processing apparatus can be used, but an apparatus as shown in FIG. 13 is preferable in that the coverage X1 and the diffusion index can be easily controlled.
- FIG. 13 is a schematic diagram showing an example of a mixing treatment apparatus that can be used when externally mixing the silica fine particles used in the present invention.
- the mixing processing device is configured to take a share in a narrow clearance portion with respect to toner particles and silica fine particles, so that the silica fine particles adhere to the toner particle surface while loosening the silica fine particles from the secondary particles to the primary particles. can do.
- the coverage X1 and the diffusion index are preferable in the present invention in that the toner particles and the silica fine particles are easily circulated in the axial direction of the rotating body, and are sufficiently mixed uniformly before the fixing proceeds. Easy to control.
- FIG. 14 is a schematic diagram showing an example of the configuration of the stirring member used in the mixing treatment apparatus.
- the mixing apparatus for externally mixing silica fine particles has a rotating body 202 having at least a plurality of stirring members 203 installed on a surface thereof, a drive unit 208 that rotationally drives the rotating body, and a gap between the stirring member 203 and the like.
- the main body casing 201 is provided.
- the clearance (clearance) between the inner peripheral portion of the main body casing 201 and the stirring member 203 gives a uniform share to the toner particles and easily adheres to the surface of the toner particles while loosening the silica fine particles from the secondary particles to the primary particles. In order to do this, it is important to keep it constant and minute.
- the diameter of the inner peripheral portion of the main body casing 1 is not more than twice the diameter of the outer peripheral portion of the rotating body 202.
- FIG. 13 shows an example in which the diameter of the inner peripheral portion of the main body casing 201 is 1.7 times the diameter of the outer peripheral portion of the rotating body 202 (the diameter of the body portion obtained by removing the stirring member 3 from the rotating body 2).
- the processing space in which the force acts on the toner particles is appropriately limited. A sufficient impact force is applied to the silica fine particles.
- the clearance is important in that a sufficient share is applied to the silica fine particles. Specifically, when the diameter of the inner peripheral part of the main body casing 1 is about 130 mm, the clearance is about 2 mm or more and about 5 mm or less. When the diameter of the inner peripheral part of the main body casing 1 is about 800 mm, the clearance is about 10 mm or more and 30 mm or less. It should be about.
- the mixing unit is used to rotate the rotating body 202 by the driving unit 208, and the toner particles and the silica fine particles charged into the mixing treatment device are stirred and mixed.
- Silica fine particles are externally added to the surface of the toner particles.
- at least a part of the plurality of stirring members 203 is formed as a feeding stirring member 203 a that sends toner particles and silica fine particles in one axial direction of the rotating body as the rotating body 202 rotates. Is done.
- At least a part of the plurality of stirring members 203 is formed as a return stirring member 203b that returns the toner particles and the silica fine particles to the other direction in the axial direction of the rotating body as the rotating body 202 rotates.
- the plate surface of the feeding stirring member 203a is inclined so as to feed the toner particles in the feeding direction (213).
- the plate surface of the stirring member 203b is inclined so as to send toner particles and silica fine particles in the return direction (212).
- the silica particles are externally added and mixed on the surface of the toner particles while repeatedly performing the feed (213) in the “feed direction” and the feed (212) in the “return direction”.
- the stirring members 203a and 203b are a set of a plurality of members arranged at intervals in the circumferential direction of the rotating body 202.
- the stirring members 203a and 203b form a pair of two members on the rotating body 202 at intervals of 180 degrees, but three members at intervals of 120 degrees or intervals of 90 degrees. It is good also as a set of many members, such as four sheets.
- a total of 12 stirring members 203a and 203b are formed at equal intervals.
- D represents the width of the stirring member
- d represents the interval indicating the overlapping portion of the stirring member.
- D has a width of about 20% to 30% with respect to the length of the rotating body 202 in FIG. FIG. 14 shows an example of 23%.
- the stirring members 203a and 203b have some overlap d between the stirring member 203b and the stirring member when an extension line is drawn in the vertical direction from the end position of the stirring member 203a.
- D is preferably 10% or more and 30% or less in terms of applying a share.
- the shape having a curved surface or the tip blade portion is A paddle structure coupled to the rotating body 2 with a rod-like arm may be used.
- the apparatus shown in FIG. 13 includes a main body casing 201 provided with a gap with the stirring member 203, and a jacket on the inner side of the main body casing 201 and the end surface 210 of the rotating body that allows a cooling medium to flow. 204.
- the apparatus shown in FIG. 13 has a raw material inlet 205 formed in the upper part of the main body casing 201 in order to introduce toner particles and silica fine particles.
- the apparatus shown in FIG. 13 has a product discharge port 206 formed in the lower portion of the main body casing 201 in order to discharge the toner subjected to the external addition mixing process from the main body casing 201.
- a raw material inlet inner piece 216 is inserted into the raw material inlet 205, and a product outlet inner piece 217 is inserted into the product outlet 206.
- the raw material inlet inner piece 216 is taken out from the raw material inlet 205 and the toner particles are put into the processing space 209 from the raw material inlet 205.
- silica fine particles are introduced into the treatment space 209 from the raw material inlet 205, and the inner piece 216 for raw material inlet is inserted.
- the rotating body 202 is rotated by the driving unit 208 (211 indicates the direction of rotation), and the processed material introduced above is externally added while being stirred and mixed by a plurality of stirring members 203 provided on the surface of the rotating body 202. Mix.
- the order of charging may be such that the silica fine particles are first charged from the raw material inlet 205 and then the toner particles are charged from the raw material inlet 205. Further, after the toner particles and the silica fine particles are mixed in advance by a mixer such as a Henschel mixer, the mixture may be supplied from the raw material inlet 205 of the apparatus shown in FIG.
- the power of the drive unit 208 it is possible to control the power of the drive unit 208 to be 0.2 W / g or more and 2.0 W / g or less as the external addition mixing processing condition, and the coverage X1 and diffusion index defined in the present invention. Is preferable in obtaining. Moreover, it is more preferable to control the power of the drive unit 208 to 0.6 W / g or more and 1.6 W / g or less.
- the treatment time is not particularly limited, but is preferably 3 minutes or more and 10 minutes or less. When the treatment time is shorter than 3 minutes, the coverage X1 and the diffusion index tend to be low.
- the number of rotations of the stirring member at the time of external mixing is not particularly limited, but when the volume of the processing space 209 is 2.0 ⁇ 10 ⁇ 3 m 3 and the shape of the stirring member 203 is as shown in FIG.
- the number of rotations of the stirring member is preferably 800 rpm or more and 3000 rpm or less. By being 800 rpm or more and 3000 rpm or less, it becomes easy to obtain the coverage X1 and the diffusion index defined in the present invention.
- a particularly preferable treatment method is to have a pre-mixing step before the external addition mixing operation.
- the silica fine particles are highly uniformly dispersed on the surface of the toner particles, so that the coverage X1 is likely to be high and the diffusion index is likely to be high.
- the power of the driving unit 208 is set to 0.06 W / g or more and 0.20 W / g or less, and the processing time is set to 0.5 minutes or more and 1.5 minutes or less. It is preferable. If the load power is lower than 0.06 W / g or the processing time is shorter than 0.5 minutes as the premixing processing condition, sufficient uniform mixing is difficult to perform as premixing. On the other hand, if the load power is higher than 0.20 W / g or the processing time is longer than 1.5 minutes as the pre-mixing processing condition, the silica fine particles are fixed on the surface of the toner particles before sufficient uniform mixing is performed. It may be done.
- the product discharge port inner piece 217 in the product discharge port 206 is taken out, the rotating body 202 is rotated by the drive unit 208, and the toner is discharged from the product discharge port 206. From the obtained toner, coarse particles and the like are separated by a sieve such as a circular vibration sieve as necessary to obtain a toner.
- ⁇ Quantification method of silica fine particles (1) Determination of the content of silica fine particles in the toner (standard addition method) 3 g of toner is put in an aluminum ring having a diameter of 30 mm, and pellets are produced at a pressure of 10 tons. Then, the intensity of silicon (Si) is obtained by wavelength dispersive X-ray fluorescence analysis (XRF) (Si intensity-1). The measurement conditions may be those optimized by the XRF apparatus to be used, but all the series of intensity measurements are performed under the same conditions. To the toner, silica fine particles having a primary particle number average particle diameter of 12 nm are added in an amount of 1.0 mass% with respect to the toner, and then mixed by a coffee mill.
- Si strength-2 the strength of Si is determined in the same manner as described above.
- Si strength-3 the strength of Si is also obtained for a sample in which silica fine particles are added and mixed at 2.0 mass% and 3.0 mass% with respect to the toner.
- silica fine particles are quantified through the following steps. 5 g of toner is weighed into a 200 ml polycup with a lid using a precision balance, 100 ml of methanol is added, and the mixture is dispersed for 5 minutes with an ultrasonic disperser. Attract the toner with a neodymium magnet and discard the supernatant. This operation of dispersing with methanol and discarding the supernatant was repeated three times.
- the magnetic substance content W (% by mass) in the magnetic toner can be obtained.
- the mass of the particle C is multiplied by 0.9666 (Fe 2 O 3 ⁇ Fe 3 O 4 ).
- the amount of silica particles added externally is calculated.
- Externally added silica fine particle amount (mass%) silica content in toner (mass%) ⁇ silica content in particle A (mass%)
- ⁇ Measurement method of coverage X1> The coverage X1 with the silica fine particles on the toner surface is calculated as follows. The following apparatus is used under the following conditions, and elemental analysis of the toner surface is performed. -Measuring device: Quantum 2000 (trade name, manufactured by ULVAC-PHI Co., Ltd.) ⁇ X-ray source: Monochrome Al K ⁇ -Xray Setting: 100 ⁇ m ⁇ (25 W (15 KV)) ⁇ Photoelectron extraction angle: 45 degrees ⁇ Neutralization condition: Combined use of neutralization gun and ion gun ⁇ Analysis area: 300 ⁇ 200 ⁇ m ⁇ Pass Energy: 58.70eV ⁇ Step size: 1.25eV ⁇ Analysis software: Maltipak (PHI)
- the peaks of C 1c B.E. 280 to 295 eV
- O 1s B.E. 525 to 540 eV
- Si 2p B.E. 95 to 113 eV
- the silica fine particles are measured alone.
- the method described in “Separation of silica fine particles from toner” described above is used.
- the elemental analysis of the silica fine particles is performed in the same manner as the elemental analysis of the toner surface described above, and the quantitative value of the Si element obtained here is Y2.
- the weight average particle diameter (D4) of the toner is calculated as follows (also calculated in the case of toner particles).
- a precise particle size distribution measuring device “Coulter Counter Multisizer 3” (registered trademark, manufactured by Beckman Coulter, Inc.) using a pore electrical resistance method equipped with an aperture tube of 100 ⁇ m is used.
- the attached dedicated software “Beckman Coulter Multisizer 3 Version 3.51” (manufactured by Beckman Coulter, Inc.) is used. The measurement is performed with 25,000 effective measurement channels.
- electrolytic aqueous solution used for the measurement special grade sodium chloride is dissolved in ion-exchanged water so that the concentration becomes 1% by mass, for example, “ISOTON II” (manufactured by Beckman Coulter, Inc.) can be used.
- the bin interval to logarithmic particle size
- the particle size bin to 256 particle size bin
- the particle size range from 2 ⁇ m to 60 ⁇ m.
- the specific measurement method is as follows. (1) In a glass 250 ml round bottom beaker for exclusive use of Multisizer 3, 200 ml of the electrolytic aqueous solution is placed and set on a sample stand, and the stirrer rod is stirred counterclockwise at 24 rpm. Then, dirt and bubbles in the aperture tube are removed by the “aperture flush” function of the dedicated software. (2) Put 30 ml of the aqueous electrolytic solution into a glass 100 ml flat bottom beaker. In this, “Contaminone N” (nonionic surfactant, anionic surfactant, 10% by weight aqueous solution of neutral detergent for pH7 precision measuring instrument cleaning, made by organic builder, manufactured by Wako Pure Chemical Industries, Ltd.
- the height position of a beaker is adjusted so that the resonance state of the liquid level of the electrolyte solution in a beaker may become the maximum.
- 10 mg of toner is added to the electrolytic aqueous solution little by little and dispersed. Then, the ultrasonic dispersion process is continued for another 60 seconds.
- the temperature of the water tank is appropriately adjusted so as to be 10 ° C. or higher and 40 ° C. or lower.
- the electrolytic aqueous solution (5) in which the toner is dispersed is dropped using a pipette, and the measurement concentration is adjusted to 5%. Measurement is performed until the number of measured particles reaches 50,000.
- the measurement data is analyzed with the dedicated software attached to the apparatus, and the weight average particle diameter (D4) is calculated.
- the “average diameter” on the “analysis / volume statistics (arithmetic average)” screen when the graph / volume% is set in the dedicated software is the weight average particle diameter (D4).
- the number average particle size of the primary particles of the silica fine particles is calculated from the silica fine particle image on the toner surface taken with a Hitachi ultra-high resolution field emission scanning electron microscope S-4800 (Hitachi High-Technologies Corporation).
- the image capturing conditions of S-4800 are as follows.
- Sample preparation A conductive paste is thinly applied to a sample table (aluminum sample table 15 mm ⁇ 6 mm), and toner is sprayed thereon. Further, air is blown to remove excess toner from the sample stage and sufficiently dry.
- the sample stage is set on the sample holder, and the height of the sample stage is adjusted to 36 mm by the sample height gauge.
- the particle diameter of at least 300 silica fine particles on the toner surface is measured to obtain the average particle diameter.
- the number average particle size of primary particles of silica fine particles (by calculating the maximum diameter of those that can be confirmed as primary particles and arithmetically averaging the obtained maximum diameter ( D1) Obtain (da).
- ⁇ Measuring method of average circularity of toner particles The average circularity of the toner particles is measured with a flow type particle image analyzer “FPIA-3000” (manufactured by Sysmex Corporation) under the measurement and analysis conditions during calibration.
- FPIA-3000 flow type particle image analyzer
- the specific measurement method is as follows. First, 20 ml of ion-exchanged water from which impure solids and the like are removed in advance is put in a glass container. In this, "Contaminone N" (nonionic surfactant, anionic surfactant, 10% by weight aqueous solution of neutral detergent for pH7 precision measuring instrument cleaning, made by organic builder, manufactured by Wako Pure Chemical Industries, Ltd. 0.2 ml of a diluted solution obtained by diluting 3) times with ion-exchanged water. Further, 0.02 g of a measurement sample is added, and a dispersion treatment is performed for 2 minutes using an ultrasonic disperser to obtain a dispersion for measurement.
- a dispersion liquid may become 10 to 40 degreeC.
- a desktop ultrasonic cleaner disperser for example, “VS-150” (manufactured by Velvo Crea) having an oscillation frequency of 50 kHz and an electric output of 150 W is used. Ion exchange water is added, and 2 ml of the above-mentioned Contaminone N is added to this water tank.
- the above-described flow type particle image analyzer equipped with “UPlanApro” (magnification 10 ⁇ , numerical aperture 0.40) as an objective lens is used, and the particle sheath “PSE-900A” (manufactured by Sysmex Corporation) is used as the sheath liquid. It was used.
- the dispersion prepared in accordance with the above procedure is introduced into the flow type particle image analyzer, and 3000 toner particles are measured in the HPF measurement mode and in the total count mode. Then, the binarization threshold at the time of particle analysis is set to 85%, the analysis particle diameter is limited to the circle equivalent diameter of 1.985 ⁇ m or more and less than 39.69 ⁇ m, and the average circularity of the toner particles is obtained.
- automatic focus adjustment is performed using standard latex particles (for example, “RESEARCH AND TEST PARTICLES Latex Microsphere Suspensions 5200A” manufactured by Duke Scientific, Inc. is diluted with ion-exchanged water). Thereafter, it is preferable to perform focus adjustment every two hours from the start of measurement.
- standard latex particles for example, “RESEARCH AND TEST PARTICLES Latex Microsphere Suspensions 5200A” manufactured by Duke Scientific, Inc. is diluted with ion-exchanged water.
- a flow-type particle image measuring apparatus which has been issued a calibration certificate issued by Sysmex Corporation, which has been calibrated by Sysmex Corporation, is used. Measurement is performed under the measurement and analysis conditions when the calibration certificate is received, except that the analysis particle diameter is limited to a circle equivalent diameter of 1.985 ⁇ m or more and less than 39.69 ⁇ m.
- the measurement principle of the flow-type particle image measuring device “FPIA-3000” is to capture flowing particles as a still image and perform image analysis.
- the sample added to the sample chamber is fed into the flat sheath flow cell by a sample suction syringe.
- the sample fed into the flat sheath flow is sandwiched between sheath liquids to form a flat flow.
- the sample passing through the flat sheath flow cell is irradiated with strobe light at 1/60 second intervals, and the flowing particles can be photographed as a still image. Further, since the flow is flat, the image is taken in a focused state.
- the particle image is picked up by a CCD camera, and the picked-up image is image-processed at an image processing resolution of 512 ⁇ 512 pixels (0.37 ⁇ 0.37 ⁇ m per pixel), the contour of each particle image is extracted, and the particle image
- the projected area S, the peripheral length L, etc. are measured.
- the equivalent circle diameter and the circularity are obtained using the area S and the peripheral length L.
- the equivalent circle diameter is the diameter of a circle having the same area as the projected area of the particle image
- the circularity is 1.000, and as the degree of unevenness on the outer periphery of the particle image increases, the circularity becomes a smaller value.
- the range of the circularity of 0.200 to 1.000 is divided into 800, the arithmetic average value of the obtained circularity is calculated, and the value is defined as the average circularity.
- ⁇ Measurement method of true specific gravity of toner and silica fine particles The true specific gravity of the toner and the silica fine particles was measured by a dry automatic densimeter autopycnometer (manufactured by Yuasa Ionics). The conditions are as follows. Cell: SM cell (10 ml) Sample amount: 2.0 g (toner), 0.05 g (silica fine particles)
- This measurement method measures the true specific gravity of a solid / liquid based on a gas phase substitution method. Similar to the liquid phase replacement method, it is based on Archimedes' principle, but uses a gas (argon gas) as a replacement medium, and therefore has high accuracy for micropores.
- argon gas argon gas
- the sample is burned at 1100 ° C. in an oxygen stream, and the amount of generated CO and CO 2 is measured by IR absorbance to measure the amount of carbon in the sample.
- the carbon amount before and after extraction of the silicone oil is compared, and the immobilization rate based on the carbon amount of the silicone oil is calculated as follows.
- the carbon amount before and after the extraction of the silicone oil is compared, and the immobilization rate based on the silicone oil-derived carbon amount is calculated as follows.
- (4) Carbon amount after silicone oil extraction] / [(carbon amount before silicone oil extraction ⁇ carbon amount after hydrophobic treatment with silane compound, etc.)] ⁇ 100, To do.
- the immobilization rate based on the amount of carbon derived from silicone oil is calculated as follows. (5) [(carbon amount after silicone oil extraction ⁇ carbon amount after hydrophobic treatment with silane compound)] / [carbon amount before silicone oil extraction] ⁇ 100, To do.
- the charging member according to the present invention has a conductive substrate and a conductive resin layer formed on the conductive substrate, and the conductive resin layer contains a binder resin and bowl-shaped resin particles.
- the binder resin contained in the conductive resin layer of the charging member is also referred to as a binder resin C.
- the surface of the charging member has a concave portion derived from the opening of the bowl-shaped resin particles and a convex portion derived from the edge of the opening of the bowl-shaped resin particles.
- the charging member can take a shape such as a roller shape, a flat plate shape, or a belt shape.
- the structure of the charging member according to the present invention will be described with reference to the charging roller shown in FIG.
- the charging member shown in FIG. 1 (1a) has a conductive substrate 1 and a conductive resin layer 3 covering its peripheral surface.
- the conductive resin layer 3 contains a binder resin C, conductive fine particles, and bowl-shaped resin particles.
- the conductive resin layer 3 may be formed of a first conductive resin layer 31 and a second conductive resin layer 32.
- FIGS. 1 (1c) and (1d) it is possible to provide one or more conductive elastic layers 2 on the inner periphery of the conductive resin layer 3.
- the conductive substrate may be bonded to the layer immediately above it via an adhesive.
- the adhesive is preferably conductive.
- the adhesive may have a known conductive agent.
- the adhesive binder resin examples include a thermosetting resin and a thermoplastic resin, and known urethane, acrylic, polyester, polyether, and epoxy resins can be used.
- a conductive agent for imparting conductivity to the adhesive it can be appropriately selected from conductive fine particles and ionic conductive agents described later, and can be used alone or in combination of two or more.
- the charging member usually has an electrical resistance value of 1 ⁇ 10 3 ⁇ or more and 1 ⁇ 10 10 ⁇ in an environment having a temperature of 23 ° C. and a relative humidity of 50% in order to improve the charging of the electrophotographic photosensitive member.
- the following is preferable.
- the charging member preferably has a crown shape that is thickest at the center in the longitudinal direction and narrows toward both ends in the longitudinal direction from the viewpoint of making the nip width in the longitudinal direction uniform with respect to the electrophotographic photosensitive member.
- the crown amount (average value of the difference between the outer diameter of the central portion and the outer diameter at positions 90 mm away from the central portion in the direction of both ends) is preferably 30 ⁇ m or more and 200 ⁇ m or less.
- the surface hardness of the charging member is preferably 90 ° or less, and more preferably 40 ° or more and 80 ° or less in terms of micro hardness (MD-1 type). By making it within this range, the contact between the charging member and the electrophotographic photosensitive member can be more reliably performed.
- the “bowl-shaped resin particles” in the present invention have a resin shell, a part of the shell is missing, the missing part constitutes the opening 51, and a spherical recess. Refers to particles having 52.
- the thickness of the shell is preferably in the range of 0.1 to 3 micrometers ( ⁇ m).
- the shell preferably has a substantially uniform thickness. “Thickness is substantially uniform” means, for example, that the thickness of the thickest part of the shell is not more than 3 times, preferably not more than 2 times the thickness of the thinnest part. Examples of bowl-shaped resin particles are shown in FIGS. 4 (4a) to 4 (4e).
- the edge of the opening 51 may be flat as shown in FIGS. 4 (4a) and 4 (4b), and in FIG. 4 (4c), FIG. 4 (4d) or FIG. 4 (4e). As shown, the edges may have irregularities.
- the maximum diameter 58 of the bowl-shaped resin particles is preferably 5 ⁇ m or more and 150 ⁇ m or less, and particularly preferably 8 ⁇ m or more and 120 ⁇ m or less. By making it within this range, contact with the electrophotographic photosensitive member can be more reliably performed.
- 71 indicates an opening of a bowl-shaped resin particle
- 74 indicates a minimum diameter of the opening
- 72 indicates a rounded recess.
- FIG. 2 (2c) and FIG. 2 (2d) show the surface layer portion of the conductive resin layer of the charging member in which the conductive resin layer is formed of the first conductive resin layer 31 and the second conductive resin layer 32, respectively. It is a fragmentary sectional view.
- the bowl-shaped resin particles 61 are present in an unexposed state on the surface of the charging member. More specifically, the opening of the bowl-shaped resin particle 61 is exposed on the surface of the first conductive resin layer 31, and the edge 53 of the opening is formed as a convex portion.
- the second conductive resin layer (thin layer) 32 is formed along the inner wall of the spherical recess 52 of the bowl-shaped resin particles 61, the surface of the charging member is made of bowl-shaped resin particles. A recess derived from the opening is formed. Furthermore, since the second conductive resin layer (thin layer) covers the edge 53 of the opening 51, a convex portion 54 derived from the edge is formed on the surface of the charging member.
- the universal hardness of the charging member surface decreases from the surface toward the inside. Thereby, the elastic deformation of the bowl-shaped resin particles described above can be further stabilized, and the stick-slip suppressing effect described above can be further enhanced.
- the method for measuring universal hardness will be described in detail later.
- the charging member according to the present invention is contained in a bowl-shaped resin particle and a conductive resin layer, and on the surface thereof, “a concave portion derived from the opening of the bowl-shaped resin particle” and “the bowl-shaped resin particle It has a convex portion derived from the edge of the opening.
- the convex portion derived from the opening comes into contact with the photosensitive member, and the concave portion has a space between the photosensitive member and the photosensitive member.
- the convex portion can be elastically deformed as shown in FIG.
- FIGS. 8 (8a) and 8 (8b) show the state before the charging member having the concave and convex portions shown in FIGS. 2 (2a) and 2 (2b) comes into contact with the electrophotographic photosensitive member, respectively.
- FIG. FIGS. 8 (8c) and 8 (8d) show the results when the charging member having the concave and convex portions shown in FIGS. 2 (2a) and 2 (2b) is in contact with the electrophotographic photosensitive member, respectively. It is a figure which shows a nip state.
- the height difference between the apex 55 of the convex part 54 derived from the edge of the opening of the bowl-shaped resin particle and the bottom 56 of the rounded concave part 52 defined by the shell of the bowl-shaped resin particle shown in FIG. 57 is preferably 5 ⁇ m or more and 100 ⁇ m or less. Moreover, it is more preferable to set it as 8 micrometers or more and 80 micrometers or less. By making it within this range, the contact between the charging member and the electrophotographic photosensitive member can be more reliably performed.
- the ratio of the height difference 57 and the maximum diameter 58 of the bowl-shaped resin particles, that is, [maximum diameter] / [height difference] is preferably 0.8 or more and 3.0 or less. By making it within this range, the contact between the charging member and the electrophotographic photosensitive member can be more reliably performed.
- the surface state of the conductive resin layer is controlled as follows by forming the uneven shape.
- the 10-point average roughness (Rzjis) of the surface is preferably 15 ⁇ m or more and 75 ⁇ m or less.
- the arithmetic average roughness (Ra) of the surface is preferably 3.0 ⁇ m or more and 7.0 ⁇ m or less.
- interval (Sm) of a surface is 20 micrometers or more and 200 micrometers or less, and 30 micrometers or more and 150 micrometers or less are preferable. If Sm is within this range, the average interval between the irregularities is short, the number of contact points between the charging member and the electrophotographic photosensitive member is increased, and contact between the charging member and the electrophotographic photosensitive member can be more reliably performed. .
- a method for measuring the ten-point average roughness (Rzjis), the uneven average interval (Sm), and the arithmetic average roughness (Ra) of the surface of the charging member will be described in detail later.
- the ratio between the maximum diameter 58 of the bowl-shaped resin particles and the minimum diameter 74 of the opening, that is, the [maximum diameter] / [minimum diameter of the opening] of the bowl-shaped resin particles is 1.1 or more, 4 0.0 or less is preferable. Thereby, the contact with the electrophotographic photosensitive member can be more reliably performed.
- the restoring speed of the elastic deformation of the charging member according to the present invention decreases from the charging member surface toward the inside.
- the elastic deformation of the bowl-shaped resin particles described above can be further stabilized, and the above-described effect of suppressing the stick slip of the cleaning member and the effect of suppressing the minute slip of the charging member can be further enhanced.
- the restoration speed according to the present invention is a value representing the speed of recovery until the bowl-shaped resin particles existing on the surface of the charging member return to the normal state from the elastic deformation.
- the high restoration speed means that the bowl-shaped resin particles are elastically deformed by abutting with the photoreceptor and then quickly recover to the original state, that is, the restoring force described above is large. As described above, this suppresses the toner component from sticking to the convex portions of the bowl-shaped resin particles. Then, new toner components sequentially adhere to the convex portions, so that it is possible to achieve the stabilization of the driven rotation as well as the suppression of minute slips.
- the restoration speed in the internal direction of the charging member is a value that contributes to the width of contact between the charging member and the photosensitive member, that is, the nip width.
- the low restoration speed means that the state of being deformed by contact continues for a certain period of time. This means that the nip width between the charging member and the photosensitive member is increased.
- the number of contact points with the photosensitive member can be increased, the pressure applied to each convex portion can be reduced, and at the same time, the convex portions that can be elastically deformed can be increased. it can. Thereby, the suppression effect of the stick slip of the cleaning member and the suppression effect of the minute slip of the charging member can be further enhanced.
- the fact that the restoration speed decreases from the surface of the charging member toward the inner direction further improves the vibration absorption effect due to elastic deformation of the bowl-shaped resin particles, and at the same time, to the convex portions of the bowl-shaped resin particles.
- the toner component adhesion control effect is further improved.
- the restoration speed according to the present invention is obtained by the following method.
- a micro hardness tester based on an indentation test method in conformity with ISO 14577 (metal material-indentation test for hardness and material parameters)
- an indenter is applied by applying a load to the elastic layer.
- the predetermined amount may be referred to as “indentation depth”.
- the microhardness tester include “Picodenter HM500” (trade name, manufactured by Fisher Instruments).
- the load applied to the indenter is unloaded, and the restoration distance ( ⁇ m) of the charging member is calculated based on the force that the indenter receives from the charging member during the unloading process.
- the graph showing the relationship between the load (mN) applied to the indenter, the indentation depth ( ⁇ m), and the restoring distance ( ⁇ m) of the charging member at the time of unloading as shown in FIG. 7 is obtained.
- the reason for using the restoration distance L 0.1 seconds after the start of unloading for the restoration speed is as follows. It is considered that the restoring speed immediately after the surface area of the charging member is released from the contact pressure regulates the restoring speed from the elastic deformation of the edge portion of the bowl-shaped resin particles. It is considered that the restoring speed immediately after the female depth region (hereinafter, also referred to as “deep layer region”) of the charging member is released from the contact pressure regulates the substantial nip width. Therefore, in the present invention, the restoration speed is calculated using the restoration distance 0.1 seconds after the start of unloading, and thus is the restoration speed immediately after the charging member is released from the contact pressure. I decided to imitate.
- the surface region according to the present invention is 10 ⁇ m deep from the surface of the charging member opposite to the side facing the conductive substrate. This is because it is considered that the restoration from the elastic deformation of the edge is substantially controlled by the restoration speed in the region having a depth of 10 ⁇ m from the surface of the charging member. For this reason, the indentation depth D ⁇ m of the microhardness tester is preferably 10 ⁇ m.
- the standard of the value of the depth t ⁇ m from the surface opposite to the side facing the substrate of the charging member that defines the deep layer region of the charging member is preferably 30 ⁇ m or more and 100 ⁇ m or less.
- the indenter indentation depth D ⁇ m in the measurement of the restoration speed of the deep region of the charging member according to the present invention is preferably 20 to 100 ⁇ m.
- [Conductive resin layer] [Binder Resin C]
- a known rubber or resin can be used as the binder resin C contained in the conductive resin layer of the charging member.
- rubber include natural rubber, a vulcanized product thereof, and synthetic rubber. The following are mentioned as a synthetic rubber. Ethylene propylene rubber, styrene butadiene rubber (SBR), silicone rubber, urethane rubber, isoprene rubber (IR), butyl rubber, acrylonitrile butadiene rubber (NBR), chloroprene rubber (CR), acrylic rubber, epichlorohydrin rubber and fluorine rubber.
- SBR styrene butadiene rubber
- silicone rubber silicone rubber
- urethane rubber isoprene rubber
- IR isoprene rubber
- NBR acrylonitrile butadiene rubber
- CR chloroprene rubber
- acrylic rubber epichlorohydrin rubber and fluorine rubber.
- a resin such as a thermo
- fluorine resin, polyamide resin, acrylic resin, polyurethane resin, acrylic urethane resin, silicone resin, and butyral resin are more preferable.
- the charging member and the electrophotographic photosensitive member can be more reliably brought into contact with each other.
- These may be used alone or in combination of two or more.
- the monomer which is the raw material of these binder resin is copolymerized, and it is good also as a copolymer.
- the binder resin used for the first conductive resin layer is formed of the first conductive resin layer and the second conductive resin layer.
- rubber is used as the binder resin used for the first conductive resin layer
- the binder resin used for the second conductive resin layer is preferably a resin. This is because the adhesion and friction between the charging member and the electrophotographic photosensitive member can be controlled more easily.
- the conductive resin layer may be formed by adding a crosslinking agent or the like to the prepolymerized binder resin material and curing or crosslinking.
- the same material as the said conductive resin layer may be used for the material of a conductive elastic layer.
- the above mixture will also be described below as a binder resin.
- the conductive resin layer of the charging member contains conductive fine particles in order to develop conductivity.
- the conductive fine particles include metal oxides, metal fine particles, and carbon black.
- these electroconductive fine particles can be used individually or in combination of 2 or more types.
- a standard for the content of the conductive fine particles in the conductive resin layer is 2 to 200 parts by weight, particularly 5 to 100 parts by weight, based on 100 parts by weight of the binder resin C.
- the types of the binder resin and conductive fine particles used for the first conductive resin layer and the second conductive resin layer may be the same or different.
- a coating layer (hereinafter also referred to as “preliminary coating layer”) in which conductive fine particles and hollow resin particles are dispersed in a binder resin C is formed on a conductive substrate.
- the surface of the preliminary coating layer is polished to remove a part of the hollow resin particles to form a bowl shape.
- a concave portion due to the opening of the bowl-shaped resin particles and a convex portion due to the edge of the opening of the bowl-shaped resin particles are formed on the surface (hereinafter also referred to as “uneven shape due to the opening of the bowl-shaped resin particles”). ).
- a method of using a so-called thermal expansion microcapsule that includes an inclusion substance inside the particle and expands the inclusion substance by applying heat to form hollow resin particles can be exemplified.
- a conductive resin composition in which thermally expanded microcapsules are dispersed together with the binder resin C and conductive fine particles is prepared, and a layer of the composition is formed on a conductive substrate, and dried, cured, or crosslinked. How to do it.
- the encapsulated substance can be expanded by the heat at the time of drying, curing, or crosslinking of the binder resin C used for the preliminary coating layer to form hollow resin particles. At this time, the particle size can also be controlled by controlling the temperature condition.
- thermoplastic resin As the binder resin C, it is necessary to use a thermoplastic resin as the binder resin C.
- thermoplastic resins are given below. Acrylonitrile resin, vinyl chloride resin, vinylidene chloride resin, methacrylic acid resin, styrene resin, urethane resin, amide resin, methacrylonitrile resin, acrylic acid resin, acrylic ester resin, methacrylic ester resin.
- a thermoplastic resin composed of at least one selected from acrylonitrile resin, vinylidene chloride resin, and methacrylonitrile resin having low gas permeability and high resilience.
- thermoplastic resins are preferable from the viewpoint that the resin particles used in the present invention are easy to produce and can be easily dispersed in the binder resin C.
- thermoplastic resins can be used alone or in combination of two or more.
- the monomer used as the raw material of these thermoplastic resins may be copolymerized and used as a copolymer.
- thermoplastic resin used for the binder resin C examples thereof include the following.
- Low boiling point liquids such as propane, propylene, butene, normal butane, isobutane, normal pentane, and isopentane; high boiling point liquids such as normal hexane, isohexane, normal heptane, normal octane, isooctane, normal decane, and isodecane.
- the above thermal expansion microcapsules can be produced by a known production method such as a suspension polymerization method, an interfacial polymerization method, an interfacial precipitation method, or a submerged drying method.
- a suspension polymerization method a polymerizable monomer, a substance to be encapsulated in the thermal expansion microcapsule, and a polymerization initiator are mixed, and this mixture is mixed in an aqueous medium containing a surfactant and a dispersion stabilizer.
- a method of suspension polymerization after dispersing can be exemplified.
- a compound having a reactive group that reacts with the functional group of the polymerizable monomer or an organic filler can also be added.
- Examples of the polymerizable monomer include the following. Acrylonitrile, methacrylonitrile, ⁇ -chloroacrylonitrile, ⁇ -ethoxyacrylonitrile, fumaronitrile, acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, citraconic acid, vinylidene chloride, vinyl acetate, acrylic acid ester (methyl acrylate, ethyl Acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, isobornyl acrylate, cyclohexyl acrylate, benzyl acrylate, etc.), methacrylic acid ester (methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate) , Isobornyl methacrylate, cyclohexyl methacrylate
- azo initiators As the polymerization initiator, known peroxide initiators and azo initiators can be used. Of these, an azo initiator is preferred from the viewpoint of control of polymerization, compatibility with a solvent, and safety during handling. Specific examples of the azo initiator are given below. 2,2'-azobisisobutyronitrile, 1,1'-azobiscyclohexane 1-carbonitrile, 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, and 2,2'- Azobis-2,4-dimethylvaleronitrile. In particular, 2,2'-azobisisobutyronitrile is preferred from the viewpoint of initiator efficiency.
- a polymerization initiator When a polymerization initiator is used, 0.01 to 5 parts by mass is preferable with respect to 100 parts by mass of the polymerizable monomer. If it exists in this range, the effect of a polymerization initiator will be exhibited and the polymer of sufficient polymerization degree can be obtained.
- an anionic surfactant As the surfactant, an anionic surfactant, a cationic surfactant, a nonionic surfactant, an amphoteric surfactant, a polymer dispersant, and the like can be used.
- a surfactant When a surfactant is used, it is preferably 0.01 to 10 parts by mass with respect to 100 parts by mass of the polymerizable monomer.
- the dispersion stabilizer include the following. Organic fine particles (polystyrene fine particles, polymethyl methacrylate fine particles, polyacrylic acid fine particles, and polyepoxide fine particles), silica (colloidal silica, etc.), calcium carbonate, calcium phosphate, aluminum hydroxide, barium carbonate, and magnesium hydroxide.
- the amount is preferably 0.01 to 20 parts by mass with respect to 100 parts by mass of the polymerizable monomer. Within this range, dispersion can be stabilized, and adverse effects such as thickening of the solvent due to an increase in unadsorbed dispersant can be prevented.
- Suspension polymerization is preferably performed in a sealed manner using a pressure vessel in order to prevent evaporation and volatilization due to vaporization of monomers and solvents. Moreover, after suspending with a disperser, it may transfer to a pressure-resistant container and suspension polymerization may be carried out, and it may be suspended and polymerized within a pressure-resistant container.
- the polymerization temperature is preferably 50 ° C to 120 ° C. If it exists in this range, the target polymer which has sufficient polymerization degree can be obtained.
- the polymerization may be carried out under atmospheric pressure, but is preferably carried out under pressure (at a pressure obtained by adding 0.1 to 1 MPa to atmospheric pressure) so as not to vaporize the substance to be included in the thermally expanded capsule.
- solid-liquid separation and washing may be performed by centrifugation or filtration.
- drying or pulverization may be performed thereafter at a temperature equal to or lower than the softening temperature of the resin constituting the thermally expanded microcapsules. Drying and pulverization can be performed by a known method, and an air dryer, a normal air dryer, and a Nauta mixer can be used. Further, drying and pulverization can be simultaneously performed by a pulverization dryer. Surfactants and dispersion stabilizers can be removed by repeating washing filtration after production.
- the preliminary coating layer As a method of forming the preliminary coating layer, electrostatic spray coating, dipping coating, roll coating, a method of bonding or coating a sheet-shaped or tube-shaped layer formed in a predetermined film thickness, and a predetermined shape in a mold Examples include a method of curing and molding the material.
- the binder resin is rubber
- the conductive substrate and the unvulcanized rubber composition can be integrally extruded by using an extruder equipped with a cross head.
- a crosshead is an extrusion die that is used at the tip of a cylinder of an extruder, which is used to form a coating layer for electric wires and wires.
- the surface of the preliminary coating layer is polished to remove a part of the hollow resin particles to obtain a bowl shape.
- a polishing method a cylindrical polishing method or a tape polishing method can be used.
- the cylindrical polishing machine include a traverse type NC cylindrical polishing machine and a plunge cut type NC cylindrical polishing machine.
- the hollow resin particles have a high resilience because they contain a gas inside. Therefore, it is preferable to select a rubber or resin having a relatively low resilience and a small elongation as the binder resin for the preliminary coating layer. Thereby, the preliminary coating layer can be easily polished, and the hollow resin particles can be hardly polished. When the preliminary coating layer in this state is polished, only a part of the hollow resin particles can be removed to form bowl-shaped resin particles. As a result, bowl-shaped resin particle openings can be formed on the surface of the preliminary coating layer.
- this method is a method of forming a concave portion derived from the opening and a convex portion derived from the edge of the opening by utilizing the difference in abrasiveness between the hollow resin particles and the preliminary coating layer, the preliminary coating layer
- rubber for the binder resin used in the above Specifically, acrylonitrile butadiene rubber, styrene butadiene rubber, or butadiene rubber having low impact resilience and low elongation can be suitably used.
- the hollow resin particles those containing a resin having a polar group are preferable from the viewpoint that the shell has low gas permeability and high resilience.
- An example of such a resin is a resin having a unit represented by the following formula (21). Furthermore, it is more preferable to have both the unit represented by the formula (21) and the unit represented by the formula (25) from the viewpoint of easy control of polishing.
- A is at least one selected from the following formulas (22), (23) and (24).
- R1 is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.
- R2 is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms
- R3 is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.
- R2 and R3 may have the same structure or different structures.
- polishing method As a polishing method, a cylindrical polishing method or a tape polishing method can be used. However, since it is necessary to remarkably bring out a difference in the polishing properties of the materials, it is preferable to make the polishing conditions faster. From this viewpoint, it is more preferable to use a cylindrical polishing method. Among cylindrical polishing methods, it is more preferable to use the plunge cut method from the viewpoint that the longitudinal direction can be polished simultaneously and the polishing time can be shortened. In addition, it is preferable that the spark-out process (polishing process at an intrusion rate of 0 mm / min) conventionally performed from the viewpoint of making the polished surface uniform be as short as possible or not performed.
- the rotational speed of the cylindrical grinding wheel is preferably 1000 rpm or more and 4000 rpm or less, particularly 2000 rpm or more and 4000 rpm.
- the penetration rate into the preliminary coating layer is preferably 5 mm / min or more and 30 mm / min or less, particularly preferably 10 mm / min or more.
- the intrusion speed is 0.1 mm / min to 0.2 mm / min within 2 seconds.
- the spark-out process (polishing process at an intrusion rate of 0 mm / min) is preferably 3 seconds or less.
- the number of rotations is preferably 50 rpm or more and 500 rpm or less, particularly 200 rpm or more and 500 rpm or less.
- the roller whose pre-coating layer has been polished can be used as it is as a charging member according to the present invention. Further, a roller having a configuration in which the layer obtained by polishing the preliminary coating layer is used as the first conductive resin layer and the second conductive resin layer is formed on the surface thereof can be used as the charging member according to the present invention.
- Second Conductive Resin Layer When there are two conductive resin layers (in the case of FIG. 1B) [Formation of Second Conductive Resin Layer]
- the surface of the first conductive resin layer obtained by the above method is coated with a conductive resin composition and dried, cured, or crosslinked to form a second conductive resin layer. Can do.
- the coating method the above-described method can be used. It is necessary to have a surface reflecting the opening of the bowl-shaped resin particles existing on the surface of the first conductive resin layer and the uneven shape due to the edges thereof. Therefore, it is preferable that the second conductive resin layer is relatively thin. As a standard of the thickness of the second conductive resin layer, it is 50 ⁇ m or less, particularly 30 ⁇ m or less.
- a method of forming the second conductive resin layer by electrostatic spray coating, dipping coating, or roll coating is more preferable.
- a coating liquid of a conductive resin composition in which conductive fine particles are dispersed in a binder resin is prepared and applied.
- the surface thereof After forming the layer obtained by polishing the preliminary coating layer or the second resin layer, the surface thereof may be subjected to electron beam irradiation, ultraviolet irradiation, or heat treatment. Moreover, in order to adjust the above-described restoration speed to a desired relationship, it is more preferable to perform electron beam irradiation, heat treatment, or both.
- FIG. 9 is a schematic diagram for explaining an example of a method of irradiating a roller-shaped member on which a conductive resin layer is formed with an electron beam.
- the member 101 on which the conductive resin layer is formed is placed on a rotating jig (not shown) and is carried into the electron beam irradiation apparatus 103 from the insertion port 102 provided with a shutter. Thereafter, the shutter is closed, the inside atmosphere of the electron beam irradiation apparatus is replaced with nitrogen, and after confirming that the oxygen concentration is 100 ppm or less, the electron beam generation unit 104 irradiates the electron beam.
- the electron beam generation unit 104 includes a vacuum chamber for electron beam acceleration and a filamentary cathode.
- thermoelectrons When this cathode is heated, thermoelectrons are emitted from the surface. The thermoelectrons thus emitted are accelerated as an acceleration voltage and then emitted as an electron beam. Further, by changing the shape of the filament and the heating temperature of the filament, the number of electron beams (irradiation dose) emitted from the cathode can be adjusted.
- D is a dose (kGy)
- K is an apparatus constant
- I is an electron current (mA)
- V is a processing speed (m / min).
- the device constant K is a constant that represents the efficiency of each device, and is an index of device performance.
- the apparatus constant K can be obtained by measuring the dose while changing the electron current and the processing speed under the condition of a constant acceleration voltage.
- a dose measurement film is attached to the roller surface, this is actually processed by an electron beam irradiation apparatus, and the dose of the electron beam of the dose measurement film is measured by a film dosimeter.
- the dosimetry film is FWT-60, and the film dosimeter is FWT-92D (both manufactured by Far West Technology).
- the dose of the electron beam in the present invention is preferably in the range of 30 kGy or more from the viewpoint of the effect of surface modification and 3000 kGy or less from the viewpoint of preventing excessive crosslinking and collapse of the surface.
- UV light intensity [mJ / cm 2 ] UV intensity [mW / cm 2 ] ⁇ irradiation time [s] (32)
- the adjustment of the accumulated amount of ultraviolet light can be performed by the irradiation time, lamp output, and distance between the lamp and the irradiated object. Moreover, you may give a gradient to integrated light quantity within irradiation time.
- the integrated light amount of ultraviolet rays can be measured using an ultraviolet integrated light amount meter UIT-150-A or UVD-S254 (both trade names) manufactured by Ushio Electric Co., Ltd.
- the integrated light amount of ultraviolet rays can be measured using an ultraviolet integrated light amount meter UIT-150-A or VUV-S172 (both trade names) manufactured by Ushio Electric Co., Ltd.
- the heat treatment is a heat treatment using a hot air circulating dryer or the like.
- heat treatment conditions it is preferable to perform heat treatment in an atmosphere of 180 ° C. to 250 ° C. for 5 minutes to 60 minutes.
- time it is more preferable to adjust the time to about 5 to 15 minutes.
- the conductive resin layer of the charging member may contain a known ionic conductive agent and insulating particles in addition to the conductive fine particles.
- volume resistivity of conductive resin layer As a measure of the volume resistivity of the conductive resin layer, it is preferably 1 ⁇ 10 2 ⁇ ⁇ cm or more and 1 ⁇ 10 16 ⁇ ⁇ cm or less in an environment of a temperature of 23 ° C. and a relative humidity of 50%. By setting it within this range, it becomes easier to appropriately charge the electrophotographic photosensitive member by discharge.
- the volume resistivity of the conductive resin layer is determined as follows. First, the conductive resin layer is cut out from the charging member into strips having a length of about 5 mm, a width of 5 mm, and a thickness of about 1 mm. Metal is vapor-deposited on both surfaces to produce an electrode and a guard electrode, and a measurement sample is obtained. When the conductive resin layer cannot be cut out with a thin film, a conductive resin composition for forming a conductive resin layer is applied onto an aluminum sheet to form a coating film, and a metal is deposited on the coating film surface. To obtain a sample for measurement.
- a voltage of 200 V is applied to the obtained measurement sample using a microammeter (trade name: ADVANTEST R8340A, ULTRAHIGHRESISTANCE METER, manufactured by Advantest Co., Ltd.). Then, the current after 30 seconds is measured, and the volume resistivity is obtained by calculating from the film thickness and the electrode area.
- the volume resistivity of the conductive resin layer can be adjusted by the conductive fine particles and the ionic conductive agent described above.
- the average particle size of the conductive fine particles is 0.01 ⁇ m to 0.9 ⁇ m, particularly 0.01 ⁇ m to 0.5 ⁇ m.
- the standard of the content of the conductive fine particles in the conductive resin layer is 2 to 80 parts by mass, particularly 20 to 60 parts by mass with respect to 100 parts by mass of the binder resin C.
- the conductive substrate used in the charging member according to the present invention is conductive and has a function of supporting a conductive resin layer and the like provided thereon.
- the material include metals such as iron, copper, stainless steel, aluminum, and nickel, and alloys thereof.
- the volume resistivity of the conductive resin layer used on the surface of the charging member according to the present invention is 1 ⁇ 10 2 ⁇ ⁇ cm or more and 1 ⁇ 10 16 ⁇ ⁇ cm or less in a temperature 23 ° C./humidity 50% RH environment. Is preferred. By setting this range, it becomes easier to appropriately charge the electrophotographic photosensitive member by discharging.
- the volume resistivity of the conductive resin layer is determined as follows. First, the conductive resin layer is cut out from the charging member into strips having a length of about 5 mm, a width of 5 mm, and a thickness of about 1 mm. A measurement sample is obtained by depositing metal on both sides. If the conductive resin layer cannot be cut out with a thin film, apply the conductive resin composition for forming the conductive resin layer on the aluminum sheet to form a coating film, and deposit metal on the coating surface to measure. For get a sample. A voltage of 200 V is applied to the obtained measurement sample using a microammeter (trade name: ADVANTEST R8340A, ULTRA HIGH RESISTANCE METER, manufactured by Advantest Corporation). Then, the current after 30 seconds is measured and calculated from the film thickness and the electrode area. The volume resistivity of the conductive resin layer can be adjusted by the conductive fine particles described above.
- the conductive fine particles preferably have an average particle size of 0.01 ⁇ m to 0.9 ⁇ m, and more preferably 0.01 ⁇ m to 0.5 ⁇ m. If it is this range, control of the volume resistivity of a conductive resin layer will become easy.
- FIG. 6 shows a schematic configuration of an example of the image forming apparatus of the present invention.
- the image forming apparatus includes a photoconductor, a charging device (charging means) for charging the photoconductor with a charging member, an exposure device (exposure means) for forming an electrostatic latent image on the surface of the charged photoconductor, A developing device (developing means) for supplying toner to the photosensitive member on which the electrostatic latent image is formed to form a toner image on the surface of the photosensitive member, and a cleaning device for collecting residual toner before the charging means (Cleaning means).
- the image forming apparatus shown in FIG. 6 further includes a transfer device (transfer means) for transferring the toner image to the transfer material, a fixing device (fixing means) for fixing the toner image, and the like. Yes.
- the photoreceptor 4 is a rotating drum type having a photosensitive layer on the outer periphery of a conductive substrate.
- the photoreceptor is driven to rotate in the direction of the arrow at a predetermined peripheral speed (process speed).
- the charging device has a contact-type charging roller 5 that is placed in contact with the photosensitive member 4 by being brought into contact with the photosensitive member 4 with a predetermined pressing force.
- the charging roller 5 is driven rotation that rotates according to the rotation of the electrophotographic photosensitive member, and charges the electrophotographic photosensitive member to a predetermined potential by applying a predetermined voltage from the charging power source 19.
- an exposure apparatus such as a laser beam scanner is used.
- An electrostatic latent image is formed by performing exposure corresponding to image information on a uniformly charged photoconductor.
- the developing device has a developing sleeve or a developing roller 6 disposed close to or in contact with the photoreceptor 4.
- the toner electrostatically processed to the same polarity as the charged polarity of the photosensitive member is subjected to reversal development to develop the electrostatic latent image to form a toner image.
- the transfer device has a contact-type transfer roller 8.
- the toner image is transferred from the photoreceptor to a transfer material 7 such as plain paper (the transfer material is conveyed by a paper feed system having a conveying member).
- the cleaning device has a blade-type cleaning member 10 and a collection container 14, and after transferring, mechanically scrapes off and collects the transfer residual toner remaining on the photoreceptor.
- the fixing device 9 is composed of a heated roll or the like, and fixes the transferred toner image on the transfer material 7 and discharges it outside the apparatus.
- a process cartridge configured to integrally support the photosensitive member, the charging device (charging device), the developing device (developing device), and the cleaning device (cleaning device) and to be detachable from the image forming apparatus can also be used. .
- the image forming apparatus may include a developing device having a process cartridge, an exposure device, and a developing member 6, and the process cartridge may be the process cartridge described above.
- average particle diameter means “volume average particle diameter” unless otherwise specified.
- all the parts and% of an Example and a comparative example are mass references
- ⁇ Production example of magnetic body 1> In a ferrous sulfate aqueous solution, 1.00 to 1.10 equivalent of caustic soda solution with respect to iron element, P 2 O 5 in an amount of 0.15% by mass in terms of phosphorus element with respect to iron element, silicon with respect to iron element An aqueous solution containing ferrous hydroxide was prepared by mixing SiO 2 in an amount of 0.50% by mass in terms of element. The pH of the aqueous solution containing ferrous hydroxide was adjusted to 8.0, and an oxidation reaction was performed at 85 ° C. while blowing air to prepare a slurry liquid having seed crystals.
- an aqueous ferrous sulfate solution was added to the slurry so that the amount was 0.90 to 1.20 equivalents relative to the initial alkali amount (sodium component of caustic soda).
- the slurry liquid was maintained at pH 7.6, and an oxidation reaction was promoted while blowing air to obtain a slurry liquid containing magnetic iron oxide.
- the water-containing slurry was once taken out. At this time, a small amount of water-containing sample was collected and the water content was measured.
- this water-containing sample was put into another aqueous medium without being dried, stirred and redispersed with a pin mill while circulating the slurry, and the pH of the redispersed liquid was adjusted to 4.8.
- n-hexyltrimethoxysilane coupling agent with respect to 100 parts by mass of magnetic iron oxide (the amount of magnetic iron oxide was calculated by subtracting the water content from the water-containing sample) was added with stirring. Hydrolysis was performed. Thereafter, the mixture was sufficiently stirred, and the dispersion was subjected to surface treatment at a pH of 8.6. The produced hydrophobic magnetic material is filtered with a filter press, washed with a large amount of water, dried at 100 ° C. for 15 minutes, and then at 90 ° C. for 30 minutes. 0.21 ⁇ m magnetic body 1 was obtained.
- polyester resin 1 ⁇ Example of production of polyester resin 1> The following components were placed in a reaction vessel equipped with a cooling tube, a stirrer, and a nitrogen introduction tube, and reacted for 10 hours while distilling off the water produced at 230 ° C. under a nitrogen stream.
- -Bisphenol A propylene oxide 2 mol adduct 75 parts by mass-Bisphenol A propylene oxide 3 mol adduct 25 parts by mass-100 parts by mass terephthalic acid-0.25 parts by mass titanium catalyst (titanium dihydroxybis (triethanolamate))
- polyester resin 1 had a main peak molecular weight (Mp) of 10,500 as measured by gel permeation chromatography (GPC).
- the above formulation was uniformly dispersed and mixed using an attritor (Mitsui Miike Chemical Co., Ltd.) to obtain a polymerizable monomer composition.
- the obtained polymerizable monomer composition was heated to 60 ° C., and 15.0 parts by mass of Fischer-Tropsch wax (melting point: 74 ° C., number average molecular weight Mn: 500) was added and dissolved. After dissolving Fischer-Tropsch wax in the polymerizable monomer composition, 7.0 parts by mass of dilauroyl peroxide as a polymerization initiator was dissolved to obtain a toner composition.
- the toner composition was put into the aqueous medium, and granulated by stirring at 12,000 rpm for 10 minutes with a TK homomixer (Special Machine Industries Co., Ltd.) in an N 2 atmosphere at 60 ° C. Thereafter, the mixture was reacted at 74 ° C. for 6 hours while stirring with a paddle stirring blade. After completion of the reaction, the suspension was cooled, washed with hydrochloric acid, filtered and dried to obtain toner particles 1. Table 1 shows the physical properties of the magnetic toner particles 1 thus obtained.
- the above mixture was premixed with a Henschel mixer, melt-kneaded with a biaxial extruder heated to 110 ° C., and the cooled kneaded product was coarsely pulverized with a hammer mill to obtain a coarsely pulverized toner product.
- the obtained coarsely pulverized product was coated with a mechanical pulverizer turbo mill (manufactured by Turbo Kogyo Co., Ltd .; coated with chromium alloy plating containing chromium carbide on the rotor and stator surfaces (plating thickness 150 ⁇ m, surface hardness HV1050)). And then mechanically pulverized (pulverized).
- the finely pulverized product obtained was classified and removed simultaneously with a multi-division classifier (Elbow Jet Classifier manufactured by Nittetsu Mining Co., Ltd.) using the Coanda effect.
- the obtained raw material toner particles were subjected to surface modification and fine powder removal using a surface modification apparatus faculty (manufactured by Hosokawa Micron Corporation) to obtain toner particles 4.
- the conditions for surface modification and fine powder removal using this surface modification apparatus were as follows: the rotational peripheral speed of the dispersion rotor was 150 m / sec, the amount of finely pulverized product was 7.6 kg per cycle, the surface modification time (cycle time) : Time from the end of the raw material supply to the time when the discharge valve opens) was 82 seconds. The temperature when discharging the toner particles was 44 ° C.
- Table 1 The physical properties of the obtained toner particles 2 are shown in Table 1.
- the apparatus shown in FIG. 13 is used in which the diameter of the inner peripheral portion of the main casing 1 is 130 mm and the volume of the processing space 209 is 2.0 ⁇ 10 ⁇ 3 m 3.
- the power was 5.5 kW, and the shape of the stirring member 203 was that of FIG.
- the overlapping width d of the stirring member 203a and the stirring member 203b in FIG. 14 is 0.25D with respect to the maximum width D of the stirring member 203, and the clearance between the stirring member 3 and the inner periphery of the main body casing 1 is 3.0 mm. .
- pre-mixing was performed in order to uniformly mix the toner particles and silica fine particles.
- the premixing conditions were such that the power of the drive unit 8 was 0.10 W / g (the rotational speed of the drive unit 8 was 150 rpm) and the processing time was 1 minute.
- the external mixing process conditions are such that the outermost end peripheral speed of the stirring member 203 is adjusted so that the power of the drive unit 208 is constant at 0.60 W / g (the rotational speed of the drive unit 8 is 1400 rpm), and the processing time For 5 minutes.
- Table 3 shows the external additive mixing conditions.
- Toner A1 was magnified and observed with a scanning electron microscope, and the number average particle size of primary particles of silica fine particles on the toner surface was measured.
- the external addition conditions and physical properties of Toner A1 were 8 nm.
- Toner Production Examples A2 to A12 Toner A2 to toner A12 were produced in the same manner as in the above production example of toner A1, except that the type and number of parts of silica fine particles, toner particles, external addition conditions, etc. shown in Tables 2 and 3 were changed. Table 3 shows external addition conditions and physical properties of the obtained toners A2 to A12.
- Henschel mixer FM10C Mitsubishi Chemical Co., Ltd.
- the pre-mixing step was not performed.
- FIG. 12 shows a plot of the coverage X1 and the diffusion index for toners A1 to A12 and toners a13 to a18.
- the toner used in the examples is indicated by a circle, and the toner used in a comparative example is indicated by an x.
- This oily mixture was added to the aqueous mixture, and 0.4 parts by mass of sodium hydroxide was further added to prepare a dispersion.
- the obtained dispersion was stirred and mixed for 3 minutes using a homogenizer, charged into a nitrogen-substituted polymerization reaction vessel, and reacted at 60 ° C. for 20 hours with stirring at 200 rpm to prepare a reaction product.
- About the obtained reaction product after repeating filtration and washing with water, it dried at 80 degreeC for 5 hours, and produced the resin particle.
- the obtained resin particles were pulverized and classified by a sonic classifier to obtain resin particles b1 having an average particle size of 12 ⁇ m.
- Production Example b7 In Production Example b1, except that the polymerizable monomer was changed to 45 parts by mass of methacrylonitrile and 55 parts by mass of methyl acrylate, resin particles were prepared and classified by the same method as in Production Example b1, and the average particle size was determined. 25 ⁇ m resin particles b7 were obtained.
- Production Example b8 In Production Example b2, except that the polymerizable monomer was changed to 45 parts by mass of acrylamide and 55 parts by mass of methacrylamide, resin particles were produced and classified in the same manner as in Production Example b2, and the average particle size was 45 ⁇ m. Resin particles b8 were obtained.
- Production Example b9 In Production Example b2, except that the polymerizable monomer was changed to 60 parts by mass of methyl methacrylate and 40 parts by mass of acrylamide, resin particles were produced and classified in the same manner as in Production Example b2, and the average particle size was 10 ⁇ m. Resin particles b9 were obtained.
- a conductive rubber composition c2 was produced in the same manner as in Production Example c1, except that the resin particle b1 was changed to the resin particle b2.
- the outer peripheral surface of the obtained roller was polished using a plunge cut type cylindrical polishing machine.
- a vitrified wheel was used as the polishing wheel, the abrasive grains were green silicon carbide (GC), and the particle size was 100 mesh.
- the rotational speed of the roller was 350 rpm, and the rotational speed of the grinding wheel was 2050 rpm.
- the rotation direction of the roller and the rotation direction of the grinding wheel were the same direction (driven direction). Polishing was performed by setting the cutting speed to 20 mm / min and setting the spark-out time (time at the cutting depth of 0 mm) to 0 seconds to produce an elastic roller e1.
- the thickness of the resin layer was adjusted to 1.5 mm.
- the crown amount of this roller was adjusted to 110 ⁇ m.
- the surface of the obtained elastic member e1 was treated by electron beam irradiation under the following conditions (described in Table 9) to obtain an elastic roller.
- an electron beam irradiation apparatus manufactured by Iwasaki Electric Co., Ltd. having a maximum acceleration voltage of 150 kV and a maximum electron current of 40 mA was used, and nitrogen gas purge was performed during irradiation.
- the treatment conditions were acceleration voltage: 80 kV, electron current: 20 mA, treatment speed: 2.04 m / min, and oxygen concentration: 100 ppm.
- the apparatus constant of the electron beam irradiation apparatus at an acceleration voltage of 80 kV is 20.4, and the dose calculated from the equation (1) is 200 kGy.
- This elastic roller had on its surface a conductive resin layer having a convex portion derived from the edge of the opening of the bowl-shaped resin particles and a concave portion derived from the opening of the bowl-shaped resin particles.
- This elastic roller was used as the charging member T1.
- Table 10 shows the evaluation results of the physical property values of the charging member.
- the charging member T3 ⁇ was the same as in Production Example T2, except that the conductive rubber composition type, polishing conditions, elastic member, hot air circulating dryer heating conditions, and electron beam irradiation conditions were changed to the conditions shown in Table 9, respectively. T15 was produced.
- Table 10 shows the evaluation results of the physical property values of the charging member. In Table 9, when a numerical value is not described, it means that no condition is given.
- FIG. 5 shows an apparatus for measuring the electrical resistance value of the charging member.
- a load is applied to both ends of the conductive substrate 1 by bearings 33 to bring the charging member 5 into contact with a cylindrical metal 39 having the same curvature as that of the electrophotographic photosensitive member in parallel.
- the cylindrical metal 39 is rotated by a motor (not shown), and a DC voltage of ⁇ 200 V is applied from the stabilized power supply 34 while the charging member 5 that is in contact is rotated.
- the current flowing at this time is measured by an ammeter 35, and the electric resistance value of the charging member is calculated.
- the load is 4.9 N each, the diameter of the metal cylinder is 30 mm, and the rotation of the metal cylinder is 45 mm / sec.
- the charging member is left in an environment having a temperature of 23 ° C. and a relative humidity of 50% for 24 hours or more, and measurement is performed using a measuring device placed in the same environment.
- the ten-point average roughness Rzjis, the arithmetic average roughness Ra, and the unevenness average interval Sm were measured according to the standard of JIS B 0601-1994 surface roughness, and the surface roughness measuring instrument “SE-3500” (trade name, stock) Using Kosaka Laboratory).
- the ten-point average roughness Rzjis and the arithmetic average roughness Ra are average values obtained by arbitrarily measuring six charging members.
- interval Sm measures the uneven
- the measurement location is the roller circumferential direction at the central portion in the longitudinal direction of the roller, the location 45 mm away from the central portion in the direction of both ends, and the location 5 mm away from the center portion in the direction of both ends.
- the conductive resin layer is cut out by using a focused ion beam processing observation apparatus (trade name: FB-2000C, manufactured by Hitachi, Ltd.) over 20 ⁇ m over 500 ⁇ m and a cross-sectional image thereof is taken.
- the obtained cross-sectional images are combined to calculate a three-dimensional image of the bowl-shaped resin particles.
- the maximum diameter 58 as shown in FIG. 3 and the minimum diameter 74 of the opening diameter shown in FIG. 4 are calculated. Further, from the three-dimensional image, the thickness of the shell of the bowl-shaped resin particles is measured at any five points of the bowl-shaped resin particles. Such measurement is performed on 10 resin particles in the field of view, and the average value of the 100 measured values obtained is calculated, and these are respectively calculated as “maximum diameter”, “minimum diameter of aperture” and “shell”. "Thickness”. When measuring the thickness of the shell, for each bowl-shaped resin particle, the thickness of the thickest part of the shell is not more than twice the thickness of the thinnest part, that is, the thickness of the shell is It was confirmed to be substantially uniform.
- a height difference 57 between the apex 55 of the convex portion 54 and the bottom portion 56 of the concave portion is calculated. Such an operation is performed for two bowl-shaped resin particles in the field of view. Then, the same measurement is carried out at 50 points in the longitudinal direction of the charging member, and an average value of a total of 100 measurement values obtained is calculated, and this value is defined as “height difference”.
- Measurement is performed using a resin particle powder by a Coulter counter multisizer. Specifically, 0.1 to 5 ml of a surfactant (alkylbenzene sulfonate) is added to 100 to 150 ml of the electrolyte solution, and 2 to 20 mg of resin particles are added to this liquid.
- the electrolyte solution in which the resin particles are suspended is dispersed with an ultrasonic disperser for 1 to 3 minutes, and the particle size distribution is measured with a Coulter counter multisizer using an aperture of 100 ⁇ m based on the volume. From the obtained particle size distribution, the volume average particle size is obtained by computer processing, and this is used as the average particle size of the resin particles.
- the measurement includes a step of pushing the indenter to a predetermined depth at a predetermined speed (hereinafter referred to as “push-in step”), and a step of unloading the load from a predetermined indentation depth position at a predetermined speed (hereinafter referred to as “unloading”). Process). From the load displacement curve as shown in FIG. 7 obtained in this way, the restoration speed for elastic deformation was calculated. A method for calculating the restoration speed will be described later.
- Restoration speed v L / 0.1 [Condition 2] Measurement of restoration speed at predetermined depth t ⁇ m
- the restoration speed v for elastic deformation was calculated in the same manner as in Condition 1.
- Example 1 A monochrome laser printer manufactured by Canon Inc. (“LBP6300” (trade name)), which is an image forming apparatus having the configuration shown in FIG. 6, is modified to a process speed of 370 mm / sec, and a voltage is applied to the charging member from the outside.
- the applied voltage was an AC voltage with a peak peak voltage (Vpp) of 1600 V, a frequency (f) of 1350 Hz, and a DC voltage (Vdc) of ⁇ 560 V.
- the image resolution was output at 600 dpi.
- the process cartridge for the printer was used as the process cartridge.
- the attached charging member was removed from the process cartridge, and the charging member T1 produced in Production Example T1 was set.
- the charging member was brought into contact with the electrophotographic photosensitive member with a pressing force of a spring of 4.9 N at one end and a total of 9.8 N at both ends.
- This process cartridge was acclimatized for 24 hours in a low-temperature and low-humidity environment (7.5 ° C./30% RH environment), and then the cleaning property was evaluated.
- the most severe evaluation condition is the second and third days for cleaning performance. This is because the aggregated toner formed through the transfer process is most likely to be generated as compared with the first or last day of image formation.
- the obtained 1,000 sheets of the horizontal line images were visually evaluated, and the cleaning property was determined according to the criteria shown in Table 11 below. If a cleaning failure occurs, the image is observed as a vertical streak image as described above.
- Evaluation of contamination of the charging member is evaluated by outputting a halftone image (an image that draws a horizontal line with a width of 1 dot and a spacing of 2 dots in the direction perpendicular to the rotation direction of the electrophotographic photosensitive member) after the endurance of 3000 horizontal image output is used. (Evaluation 5 in Table 13). Further, in the same manner as above, after 6,000 sheets endurance output (Evaluation 6 in Table 13), after output of 9000 sheets (Evaluation 7 in Table 13), after output of 10 thousand sheets (Evaluation 8 in Table 13), A halftone image was output. In the evaluation, a halftone image was visually observed, and whether or not the above-described dot-like image due to the contamination of the charging member was recognized in the image was determined according to the criteria described in Table 12 below.
- Example 2 to 34 Evaluation was performed in the same manner as in Example 1 except that the combination of the toner and the charging member was changed as shown in Table 13. The results are shown in Table 13.
Abstract
Description
該帯電部材は、導電性基体と導電性樹脂層を有し、
該導電性樹脂層は、結着樹脂Cとボウル形状の樹脂粒子とを含み、
該帯電部材の表面は、該ボウル形状の樹脂粒子の開口に由来する凹部と、該ボウル形状の樹脂粒子の開口エッジに由来する凸部とを有し、
該トナーは、結着樹脂T及び着色剤を含有するトナー粒子と、無機微粒子とを含有するトナーであって、
該無機微粒子がシリカ微粒子であり、
該トナーは、該シリカ微粒子をトナー粒子100質量部あたり0.40質量部以上1.50質量部以下含有し、
該シリカ微粒子は、シリカ原体100質量部に対して、15.0質量部以上40.0質量部以下のシリコーンオイルによって処理されており、該シリコーンオイルの炭素量基準の固定化率(%)が70%以上であり、X線光電子分光装置(ESCA)により求めた、該トナーの表面の該シリカ微粒子による被覆率X1が50.0面積%以上75.0面積%以下であり、該シリカ微粒子による理論被覆率をX2としたとき、下記式1で示される拡散指数が下記式2を満足するトナーであることを特徴とする画像形成装置に関する。
(式1)拡散指数=X1/X2
(式2)拡散指数≧-0.0042×X1+0.62
本発明者らは、クリーニング不良の発生の抑制と、帯電部材の汚れを抑制、とを達成するためのトナーの条件として、下記の4点が必要であると考察している。
外添剤がトナーへ埋め込まれてしまうと、上記外添剤により付与したトナーの下記離型性や、前述したスペーサー効果が発現できなくなる。
(2)トナーの離型性
これにより、前記凝集トナーの発生が抑制できると同時に、帯電部材の表面へのトナー成分の固着が抑制できる
(3)トナーの潤滑性
これにより、帯電部材の表面に付着したトナー成分が、入れ替わりやすくなる。
(4)トナーのほぐれ易さ
(式1)拡散指数=X1/X2
(式2)拡散指数≧-0.0042×X1+0.62
(式4)理論被覆率X2(面積%)=31/2/(2π)×(dt/da)×(ρt/ρa)×C×100
da:シリカ微粒子の個数平均粒径(D1)
dt:トナーの重量平均粒径(D4)
ρa:シリカ微粒子の真比重
ρt:トナーの真比重
C:シリカ微粒子の質量/トナーの質量
(Cは後述するトナー中のシリカ微粒子の含有量を用いる。)
(式3)拡散指数<-0.0042×X1+0.62
例えば、シリコーンオイルによる表面処理では、シリカ微粒子を反応槽に入れる。そして、窒素雰囲気下、撹拌しながらアルコール水を添加し、シリコーンオイルを反応槽に導入して表面処理を行い、さらに加熱撹拌して溶剤を除去し、解砕処理を行う。アルコキシシラン及びシラザンの少なくとも一方による表面処理では、窒素雰囲気下、撹拌しながら、アルコキシシラン及びシラザンの少なくとも一方を導入して表面処理を行い、さらに加熱撹拌して溶剤を除去した後に冷却する。
当該混合処理装置は、トナー粒子とシリカ微粒子に対して、狭いクリアランス部において、シェアがかかる構成になっているために、シリカ微粒子を二次粒子から一次粒子へとほぐしながら、トナー粒子表面に付着することができる。
図14に示すように、複数の撹拌部材203の少なくとも一部が、回転体202の回転に伴って、トナー粒子及びシリカ微粒子を回転体の軸方向の一方向に送る送り用撹拌部材203aとして形成される。また、複数の撹拌部材203の少なくとも一部が、トナー粒子及びシリカ微粒子を、回転体202の回転に伴って、回転体の軸方向の他方向に戻す戻し用撹拌部材203bとして形成されている。
これにより、「送り方向」への送り(213)と、「戻り方向」への送り(212)とを繰り返し行いながら、トナー粒子の表面にシリカ微粒子の外添混合処理を行う。
(1)トナー中のシリカ微粒子の含有量の定量(標準添加法)
トナー3gを直径30mmのアルミリングに入れ、10トンの圧力でペレットを作製する。そして、波長分散型蛍光X線分析(XRF)により、珪素(Si)の強度を求める(Si強度-1)。なお、測定条件は使用するXRF装置で最適化されたものであれば良いが、一連の強度測定はすべて同一条件で行うこととする。トナーに、一次粒子の個数平均粒径が12nmのシリカ微粒子を、トナーに対して1.0質量%添加して、コーヒーミルにより混合する。
混合後、上記と同様にペレット化したのちに、上記同様にSiの強度を求める(Si強度-2)。同様の操作を、シリカ微粒子を、トナーに対して2.0質量%、3.0質量%添加混合したサンプルにおいても、Siの強度を求める(Si強度-3,Si強度-4)。Si強度-1乃至4を用いて、標準添加法によりトナー中のシリカ含有量(質量%)を計算する。
トナーが磁性体を含有する場合、次の工程を経て、シリカ微粒子の定量を行う。
トナー5gを、精密天秤を用いて200mlの蓋付きポリカップに秤量し、メタノールを100ml加え、超音波分散機で5分間分散させる。ネオジム磁石によりトナーを引き付け、上澄み液を捨てる。このメタノールによる分散と上澄みを捨てる操作を3回繰り返した。その後、10%NaOHを100mlと、「コンタミノンN」(非イオン界面活性剤、陰イオン界面活性剤、有機ビルダーからなるpH7の精密測定器洗浄用中性洗剤の10質量%水溶液、和光純薬工業社製)を数滴加え、軽く混合したのち、24時間静置する。その後、再びネオジム磁石を用いて分離する。なお、この際にNaOHが残留しないように繰り返し蒸留水ですすぐ。回収された粒子を真空乾燥機により十分に乾燥させ、粒子Aを得る。上記操作により、外添されたシリカ微粒子は溶解、除去される。
3gの粒子Aを直径30mmのアルミリングに入れ、10トンの圧力でペレットを作製し、波長分散型蛍光X線分析(XRF)により、Siの強度を求める(Si強度-5)。Si強度-5とトナー中のシリカ含有量の定量で使用したSi強度-1乃至4を利用して、粒子A中のシリカ含有量(質量%)を計算する。
5gの粒子Aに対して、100mlのテトラヒドロフランを加え、良く混合した後に超音波分散を10分間行う。磁石により磁性粒子を引き付け、上澄み液を捨てる。この作業を5回繰り返し、粒子Bを得る。この操作で、磁性体以外の樹脂等の有機成分はほぼ取り除くことができる。ただし、樹脂中のテトラヒドロフラン不溶解分が残存する可能性があるため、上記操作で得られた粒子Bを800℃まで加熱して残存する有機成分を燃焼させることが好ましく、加熱後に得られた粒子Cを、トナーに含有されていた磁性体と近似することができる。
外添されたシリカ微粒子量(質量%)=トナー中のシリカ含有量(質量%)-粒子A中のシリカ含有量(質量%)
トナー表面のシリカ微粒子による被覆率X1は、以下のようにして算出する。
下記装置を下記条件にて使用し、トナー表面の元素分析を行う。
・測定装置:Quantum2000(商品名、アルバックファイ株式会社製)
・X線源:モノクロAl Kα
・Xray Setting:100μmφ(25W(15KV))
・光電子取りだし角:45度
・中和条件:中和銃とイオン銃の併用
・分析領域:300×200μm
・Pass Energy:58.70eV
・ステップサイズ:1.25eV
・解析ソフト:Maltipak(PHI社)
被覆率X1(面積%)=Y1/Y2×100
尚、本測定の精度を向上させるために、Y1及びY2の測定を、2回以上行うことが好ましい。
トナーの重量平均粒径(D4)は、以下のようにして算出する(トナー粒子の場合も同様に算出する)。測定装置としては、100μmのアパーチャチューブを備えた細孔電気抵抗法による精密粒度分布測定装置「コールター・カウンター Multisizer 3」(登録商標、ベックマン・コールター社製)を用いる。測定条件の設定及び測定データの解析は、付属の専用ソフト「ベックマン・コールター Multisizer 3 Version3.51」(ベックマン・コールター社製)を用いる。尚、測定は実効測定チャンネル数2万5千チャンネルで行う。
(1)Multisizer 3専用のガラス製250ml丸底ビーカーに前記電解水溶液200mlを入れ、サンプルスタンドにセットし、スターラーロッドの撹拌を反時計回りで24回転/秒にて行う。そして、専用ソフトの「アパーチャのフラッシュ」機能により、アパーチャチューブ内の汚れと気泡を除去しておく。
(2)ガラス製の100ml平底ビーカーに前記電解水溶液30mlを入れる。この中に分散剤として「コンタミノンN」(非イオン界面活性剤、陰イオン界面活性剤、有機ビルダーからなるpH7の精密測定器洗浄用中性洗剤の10質量%水溶液、和光純薬工業社製)をイオン交換水で3質量倍に希釈した希釈液を0.3ml加える。
(3)発振周波数50kHzの発振器2個を、位相を180度ずらした状態で内蔵し、電気的出力120Wの超音波分散器「Ultrasonic Dispersion System Tetora150」(日科機バイオス社製)を準備する。超音波分散器の水槽内に3.3lのイオン交換水を入れ、この水槽中にコンタミノンNを2ml添加する。
(4)前記(2)のビーカーを前記超音波分散器のビーカー固定穴にセットし、超音波分散器を作動させる。そして、ビーカー内の電解水溶液の液面の共振状態が最大となるようにビーカーの高さ位置を調整する。
(5)前記(4)のビーカー内の電解水溶液に超音波を照射した状態で、トナー10mgを少量ずつ前記電解水溶液に添加し、分散させる。そして、さらに60秒間超音波分散処理を継続する。尚、超音波分散にあたっては、水槽の水温が10℃以上40℃以下となる様に適宜調節する。
(6)サンプルスタンド内に設置した前記(1)の丸底ビーカーに、ピペットを用いてトナーを分散した前記(5)の電解水溶液を滴下し、測定濃度が5%となるように調整する。そして、測定粒子数が50000個になるまで測定を行う。
(7)測定データを装置付属の前記専用ソフトにて解析を行い、重量平均粒径(D4)を算出する。尚、専用ソフトでグラフ/体積%と設定したときの、「分析/体積統計値(算術平均)」画面の「平均径」が重量平均粒径(D4)である。
シリカ微粒子の一次粒子の個数平均粒径は、日立超高分解能電界放出形走査電子顕微鏡S-4800((株)日立ハイテクノロジーズ)にて撮影されるトナー表面のシリカ微粒子画像から算出される。S-4800の画像撮影条件は以下の通りである。
試料台(アルミニウム試料台15mm×6mm)に導電性ペーストを薄く塗り、その上にトナーを吹きつける。さらにエアブローして、余分なトナーを試料台から除去し十分乾燥させる。試料台を試料ホルダにセットし、試料高さゲージにより試料台高さを36mmに調節する。
シリカ微粒子の一次粒子の個数平均粒径の算出は、S-4800の反射電子像観察により得られた画像を用いて行う。反射電子像は二次電子像と比べてシリカ微粒子のチャージアップが少ないため、シリカ微粒子の粒径を精度良く測定することが出来る。
コントロールパネルの倍率表示部内をドラッグして、倍率を100000(100k)倍に設定する。操作パネルのフォーカスつまみ[COARSE]を回転させ、ある程度焦点が合ったところでアパーチャアライメントの調整を行う。コントロールパネルの[Align]をクリックし、アライメントダイアログを表示し、[ビーム]を選択する。操作パネルのSTIGMA/ALIGNMENTつまみ(X,Y)を回転し、表示されるビームを同心円の中心に移動させる。次に[アパーチャ]を選択し、STIGMA/ALIGNMENTつまみ(X,Y)を一つずつ回し、像の動きを止める又は最小の動きになるように合わせる。アパーチャダイアログを閉じ、オートフォーカスで、ピントを合わせる。この操作を更に2度繰り返し、ピントを合わせる。
トナー粒子の平均円形度は、フロー式粒子像分析装置「FPIA-3000」(シスメックス社製)によって、校正作業時の測定及び解析条件で測定する。
円形度=2×(π×S)1/2/L
シリカ微粒子の見掛け密度の測定は、100mlのメスシリンダーに、紙の上にのせた測定試料をゆっくり加えて100mlになるようにし、試料を加える前と後のメスシリンダーの質量差を求め次式によって算出する。なお、試料をメスシリンダーに加える場合、紙を叩いたりしないよう注意する。
見掛け密度(g/L)=(100ml投入した時点の質量(g))/0.1
トナー及びシリカ微粒子の真比重は、乾式自動密度計オートピクノメーター(ユアサアイオニクス社製)により測定した。条件は下記の通りである。
セル :SMセル(10ml)
サンプル量 :2.0g(トナー)、0.05g(シリカ微粒子)
(遊離シリコーンオイルの抽出)
(1)ビーカーにシリカ微粒子0.50g、クロロホルム40mlを入れ、2時間攪拌する。
(2)攪拌を止めて、12時間静置する。
(3)サンプルをろ過して、クロロホルム40mlで3回洗浄する。
酸素気流下、1100℃で試料を燃焼させ、発生したCO、CO2量をIRの吸光度により測定して、試料中の炭素量を測定する。シリコーンオイルの抽出前後での炭素量を比較して、シリコーンオイルの炭素量基準の固定化率を下記の通り計算する。
(2)プレスした試料0.15gを精秤し、燃焼用ボードに乗せ、堀場製作所EMA-110で測定する。
(3)[シリコーンオイル抽出後の炭素量]/[シリコーンオイル抽出前の炭素量]×100、をシリコーンオイルの炭素量基準の固定化率とする。
なお、シラン化合物等で疎水化処理した後に、シリコーンオイルによる表面処理を行っている場合は、まず、シラン化合物等で疎水化処理した後に試料中の炭素量を測定する。そして、シリコーンオイルによる表面処理後に、シリコーンオイルの抽出前後での炭素量を比較して、シリコーンオイル由来の炭素量基準の固定化率を下記の通り計算する。
(4)[シリコーンオイル抽出後の炭素量]/[(シリコーンオイル抽出前の炭素量-シラン化合物等で疎水処理後の炭素量)]×100、をシリコーンオイルの炭素量基準の固定化率とする。
一方、シリコーンオイルによる表面処理後にシラン化合物等で疎水処理を行っている場合は、シリコーンオイル由来の炭素量基準の固定化率を下記の通り計算する。
(5)[(シリコーンオイル抽出後の炭素量-シラン化合物等で疎水処理後の炭素量)]/[シリコーンオイル抽出前の炭素量]×100、をシリコーンオイルの炭素量基準の固定化率とする。
本発明に係る帯電部材は、導電性基体及び該導電性基体上に形成された導電性樹脂層を有し、該導電性樹脂層は、結着樹脂及びボウル形状の樹脂粒子を含有する。以下、帯電部材の導電性樹脂層に含まれる結着樹脂を結着樹脂Cとも称する。
図2(2a)及び図2(2b)は、帯電部材の表面の導電性樹脂層31の部分断面図である。これらの帯電部材において、ボウル形状の樹脂粒子61が、前記帯電部材の表面に露出している。そして、帯電部材の表面は、表面に露出しているボウル形状の樹脂粒子の開口51に由来する凹部52と、表面に露出しているボウル形状の樹脂粒子の開口のエッジ53に由来する凸部54とを有している。
復元速度v(μm/sec)=L(μm)/0.1(sec) ・・・(30)
[結着樹脂C]
帯電部材の導電性樹脂層に含有される結着樹脂Cとしては、公知のゴムまたは樹脂を使用することができる。ゴムとしては、例えば、天然ゴムやこれを加硫処理したもの、合成ゴムを挙げることができる。合成ゴムとしては以下のものが挙げられる。エチレンプロピレンゴム、スチレンブタジエンゴム(SBR)、シリコーンゴム、ウレタンゴム、イソプレンゴム(IR)、ブチルゴム、アクリロニトリルブタジエンゴム(NBR)、クロロプレンゴム(CR)、アクリルゴム、エピクロルヒドリンゴム及びフッ素ゴム。樹脂としては、例えば、熱硬化性樹脂、熱可塑性樹脂の如き樹脂が使用できる。中でも、フッ素樹脂、ポリアミド樹脂、アクリル樹脂、ポリウレタン樹脂、アクリルウレタン樹脂、シリコーン樹脂、ブチラール樹脂がより好ましい。上記の材料を使用することにより、帯電部材と電子写真感光体との当接をより確実に行うことができる。これらは、単独で用いてもよく、2種以上を混合して用いてもよい。また、これら結着樹脂の原料である単量体を共重合させ、共重合体としてもよい。
帯電部材の導電性樹脂層は、導電性を発現するために導電性微粒子を含有する。導電性微粒子の具体例としては、金属酸化物、金属微粒子、カーボンブラックが挙げられる。また、これらの導電性微粒子を、単独で又は2種以上を組み合わせて用いることができる。導電性樹脂層中における導電性微粒子の含有量の目安としては、結着樹脂C100質量部に対して2~200質量部、特には5~100質量部である。第1の導電性樹脂層と第2の導電性樹脂層に使用する結着樹脂及び導電性微粒子の種類は、同じであっても、異なっていてもよい。
前記導電性樹脂層を形成する方法を以下に説明する。
まず、結着樹脂C中に導電性微粒子及び中空の樹脂粒子を分散させた被覆層(以下、「予備被覆層」とも称す。)を導電性基体上に形成する。次に、この予備被覆層の表面を研磨して中空の樹脂粒子の一部を削除してボウル形状とする。これにより、表面にボウル形状の樹脂粒子の開口による凹部と、ボウル形状の樹脂粒子の開口のエッジによる凸部が形成される(以下、「ボウル形状の樹脂粒子の開口による凹凸形状」とも称す。)。
まず、予備被覆層に中空の樹脂粒子を分散させる方法について説明する。一つの方法としては、内部に気体を含有している中空形状の樹脂粒子を、結着樹脂C及び導電性微粒子とともに分散させた導電性樹脂組成物の塗膜を導電性基体上に形成し、当該塗膜を、乾燥、硬化または架橋させる方法が挙げられる。中空の樹脂粒子に用いる材料としては、前記結着樹脂Cとしての樹脂あるいは公知の樹脂を挙げることができる。
続いて、予備被覆層の形成方法について説明する。
研磨方法としては、円筒研磨方法やテープ研磨法を使用することができるが、材料の研磨性の差を顕著に引き出す必要があるため、より速く研磨する条件とすることが好ましい。この観点から、円筒研磨法を使用することがより好ましい。円筒研磨法のなかでも、長手方向を同時に研磨でき、研磨時間が短縮できるという観点から、プランジカット方式を使用することが、更に好ましい。また、研磨面を均一にするという観点から従来行われていたスパークアウト工程(侵入速度0mm/minでの研磨工程)を、できるだけ短時間とすること、もしくは行わないことが好ましい。
[第2の導電性樹脂層の形成]
前記方法にて得られた第1の導電性樹脂層の表面に、導電性樹脂組成物を被覆し、乾燥、硬化、または、架橋を行うことにより、第2の導電性樹脂層を形成することができる。被覆方法としては、前記の方法を使用することができる。第1の導電性樹脂層の表面に存在するボウル形状の樹脂粒子の開口およびそのエッジによる凹凸形状を反映した表面とすることが必要である。そのため、第2の導電性樹脂層は、比較的薄いことが好ましい。第2の導電性樹脂層の厚さの目安としては、50μm以下、特には30μm以下である。従って、上記被覆方法の中でも、静電スプレー塗布、ディッピング塗布、またはロール塗布により第2の導電性樹脂層を形成する方法がより好ましい。これらの塗布法を使用する場合、結着樹脂中に導電性微粒子を分散した導電性樹脂組成物の塗布液を作製し、塗布を行う。
前記予備被覆層を研磨した層、あるいは、前記第2の樹脂層を形成した後、その表面に、電子線照射、紫外線照射、熱処理を行っても良い。また、前述の復元速度を所望の関係に調整するためには、電子線照射、熱処理、または、その両方を行うことがより好ましい。
上記のように電子線照射することにより、前述の復元速度を所望の関係に調整することができる。
D=(K・I)/V ・・・(31)
紫外線の照射には、高圧水銀ランプ、メタルハライドランプ、低圧水銀ランプ、エキシマUVランプなどを用いることができ、これらのうち、紫外線の波長が150nm以上480nm以下の光を豊富に含む紫外線源が用いることが好ましい。なお、紫外線の積算光量は、下記計算式(32)のように定義される。
紫外線積算光量[mJ/cm2]=紫外線強度[mW/cm2]×照射時間[s] ・・・(32)
熱処理は、熱風循環乾燥機等を使用した加熱処理である。熱処理の条件としては、180℃~250℃分の雰囲気下、5分乃至60分間加熱処理を行うことが好ましい。前述の復元速度を所望の関係に調整するためには、時間を5乃至15分程度に調整することが更に好ましい。
帯電部材の導電性樹脂層は、前記の導電性微粒子に加えて、公知のイオン導電剤および絶縁性粒子を含有させてもよい。
導電性樹脂層の体積抵抗率の目安としては、温度23℃、相対湿度50%の環境において、1×102Ω・cm以上、1×1016Ω・cm以下とすることが好ましい。この範囲内とすることで、放電により電子写真感光体を適切に帯電することが、より容易になる。
本発明に係る帯電部材に用いられる導電性基体は、導電性を有し、その上に設けられる導電性樹脂層等を支持する機能を有するものである。材質としては、例えば、鉄、銅、ステンレス鋼、アルミニウム、ニッケルの如き金属やその合金を挙げることができる。
本発明に係る帯電部材の表面に用いる導電性樹脂層の体積抵抗率は、温度23℃/湿度50%RH環境において、1×102Ω・cm以上1×1016Ω・cm以下であることが、好ましい。本範囲とすることで、電子写真感光体を、放電により適切に帯電することが、より容易になる。
本発明の画像形成装置の一例の概略構成を図6に示す。
感光体、帯電装置(帯電手段)及び現像装置(現像手段)、クリーニング装置(クリーニング手段)を一体に支持し、画像形成装置から着脱可能に構成されたプロセスカートリッジ(図10)を用いることもできる。
硫酸第一鉄水溶液に、鉄元素に対し1.00~1.10当量の苛性ソーダ溶液、鉄元素に対しリン元素換算で0.15質量%となる量のP2O5、鉄元素に対し珪素元素換算で0.50質量%となる量のSiO2を混合し、水酸化第一鉄を含む水溶液を調製した。水酸化第一鉄を含む水溶液のpHを8.0とし、空気を吹き込みながら85℃で酸化反応を行い、種晶を有するスラリー液を調製した。
冷却管、撹拌機及び窒素導入管の付いた反応槽中に、下記成分を入れ、230℃で窒素気流下に生成する水を留去しながら10時間反応させた。
・ビスフェノールA プロピレンオキサイド2モル付加物 75質量部
・ビスフェノールA プロピレンオキサイド3モル付加物 25質量部
・テレフタル酸 100質量部
・チタン系触媒 0.25質量部
(チタニウムジヒドロキシビス(トリエタノールアミネート))
イオン交換水720質量部に0.1M-Na3PO4水溶液450質量部を投入して60℃に加温した後、1.0M-CaCl2水溶液67.7質量部を添加して、分散安定剤を含む水系媒体を得た。
・スチレン 78.0質量部
・n-ブチルアクリレート 22.0質量部
・ジビニルベンゼン 0.6質量部
・モノアゾ染料の鉄錯体(T-77:保土谷化学工業(株)) 3.0質量部
・磁性体1 90.0質量部
・ポリエステル樹脂1 5.0質量部
反応終了後、懸濁液を冷却し、塩酸を加えて洗浄した後に濾過・乾燥してトナー粒子1を得た。得られた磁性トナー粒子1の物性を表1に示す。
・スチレンアクリル共重合体 100質量部
(スチレンとn-ブチルアクリレートの質量比が78.0:22.0、メインピーク分子量Mpが10000)
・磁性体1 90質量部
・モノアゾ染料の鉄錯体(T-77:保土谷化学工業(株)) 2質量部
・フィッシャートロプシュワックス 4質量部
(融点:74℃、数平均分子量Mn:500)
〔トナーの製造例A1〕
上記トナー粒子1に対して、図13に示す装置を用いて、外添混合処理を行った。
上記トナーA1の製造例において、表2、表3に示す、シリカ微粒子の種類及び添加部数、トナー粒子、外添条件等へ変更した以外は同様にして、トナーA2乃至トナーA12を製造した。得られたトナーA2乃至トナーA12の外添条件、物性を表3にそれぞれ示す。
上記トナーA1の製造例において、表2、表3に示す、シリカ微粒子の種類及び添加部数、トナー粒子、外添装置、外添条件等へ変更した以外は同様にして、トナーa13乃至トナーa18を製造した。得られたトナーa13乃至トナーa18の外添条件、物性を表3にそれぞれ示す。
〔製造例b1〕
イオン交換水4000質量部と、分散安定剤としてコロイダルシリカ9質量部及びポリビニルピロリドン0.15質量部を添加し、水性混合液を調製した。次いで、重合性単量体としてアクリロニトリル50質量部、メタクリロニトリル45質量部、メチルメタクリレート5質量部と、内包物質としてノルマルヘキサン12.5質量部と、重合開始剤としてジクミルパーオキシド0.75質量部からなる油性混合液を調製した。この油性混合液を、前記水性混合液に添加し、更に水酸化ナトリウム0.4質量部を添加することにより、分散液を調製した。得られた分散液をホモジナイザーを用いて3分間攪拌混合し、窒素置換した重合反応容器内へ仕込み、200rpmの撹拌下、60℃で20時間反応させることにより、反応生成物を調製した。得られた反応生成物について、ろ過と水洗を繰り返した後、80℃で5時間乾燥して樹脂粒子を作製した。得られた樹脂粒子を音波式分級機により解砕して分級することによって、平均粒径12μmの樹脂粒子b1を得た。
製造例b1において、コロイダルシリカの添加部数を4.5質量部に変更した以外は製造例b1と同様の方法で樹脂粒子を作製した。また同様に分級して平均粒径50μmの樹脂粒子b2を得た。
製造例b2で分級した粒経違いの平均粒径が下記表4に記載の粒子を樹脂粒子b3~b6とした。
製造例b1において、重合性単量体をメタクリロニトリル45質量部及びメチルアクリレート55質量部に変更した以外は、製造例b1と同様の方法で樹脂粒子を作製し、分級して、平均粒径25μmの樹脂粒子b7を得た。
製造例b2において、重合性単量体をアクリルアミド45質量部及びメタクリルアミド55質量部に変更した以外は、製造例b2と同様の方法で樹脂粒子を作製し、分級して、平均粒径45μmの樹脂粒子b8を得た。
製造例b2において、重合性単量体をメチルメタクリレート60質量部及びアクリルアミド40質量部に変更した以外は、製造例b2と同様の方法で樹脂粒子を作製し、分級して、平均粒径10μmの樹脂粒子b9を得た。
製造例b1において、重合性単量体をアクリルアミド100質量部に変更した以外は、製造例b1と同様の方法で樹脂粒子を作製した。また、同様に分級して平均粒径8μmの樹脂粒子b10を得た。
〔製造例c1〕
アクリロニトリルブタジエンゴム(NBR)(商品名:N230SV、JSR社製)100質量部に対し下記表6の成分(1)の欄に示す他の4種類の材料を加えて、50℃に調節した密閉型ミキサーにて15分間混練した。これに表5の成分(2)の欄に示す3種類の材料を添加した。次いで、温度25℃に冷却した二本ロール機にて10分間混練し、導電性ゴム組成物c1を作製した。
樹脂粒子b1を樹脂粒子b2に変更した以外は、製造例c1と同様にして、導電性ゴム組成物c2を作製した。
樹脂粒子の種類及び添加部数を表8に示すように変更した以外は、製造例c1と同様にして、導電性ゴム組成物c3~c8を作製した。
スチレンブタジエンゴム(SBR)(商品名:SBR1500、JSR社製)100質量部に対し下記表7の成分(1)の欄に示す他の6種類の材料を加えて、80℃に調節した密閉型ミキサーにて15分間混練した。これに表6の成分(2)の欄に示す3種類の材料を添加した。次いで、温度25℃に冷却した二本ロール機にて10分間混練し、導電性ゴム組成物c9を作製した。
樹脂粒子の種類及び添加部数を表8に示すように変更した以外は、製造例c1と同様にして、導電性ゴム組成物c10、c11、c14及びc15を作製した。
製造例c1において、アクリロニトリルブタジエンゴムをブタジエンゴムBR)(「JSR BR01」(商品名、JSR(株)製)に変更し、カーボンブラックを30質量部に変更した。更に、樹脂粒子の種類及び添加部数を表8に示すように変更した。上記以外は、製造例c1と同様にして、導電性ゴム組成物c12及びc13を作製した。
クロロプレンゴム(商品名:ショープレンWRT、昭和電工(株)製)75質量部に対し下記表8の成分(1)の欄に示す他の3種類の材料を加えて、50℃に調節した密閉型ミキサーにて15分間混練した。これに表7の成分(2)の欄に示す3種類の材料を添加し、温度20℃に冷却した二本ロール機で15分間混練し、導電性ゴム組成物c18を作製した。
〔製造例T1〕
[導電性基体の作製]
直径6mm、長さ252.5mmのステンレス製丸棒に、カーボンブラックを10質量%含有させた熱硬化性接着剤を塗布し、乾燥したものを導電性基体とした。
クロスヘッドを具備する押出成形装置を用いて、導電性基体を中心軸として、その外周部を、同軸円筒状に導電性ゴム組成物c1によって被覆し、ゴムローラを得た。被覆したゴム組成物の厚みは、1mmに調整した。このローラを、熱風炉にて160℃で1時間加熱したのち、ゴム組成物の層の両端部を除去して、長さを224.2mmとし、更に、160℃で1時間2次加熱を行い、厚さが2mmのゴム組成物からなる予備被覆層を有するローラを作製した。
導電性ゴム組成物の種類を表9に示す条件に変更した以外は、製造例T1と同様にして、弾性部材e2を得た。得られた弾性部材e2を、まず、熱風循環乾燥機にて温度200℃で30分間加熱した。その後、製造例T1と同様にして、電子線照射により処理を行い、帯電部材T2を得た。帯電部材物性値の評価結果を表10に示す。
導電性ゴム組成物の種類、研磨条件、弾性部材、熱風循環乾燥機加熱条件、電子線照射条件を、各々表9に示す条件に変更した以外は、製造例T2と同様にして帯電部材T3~T15を作製した。帯電部材物性値の評価結果を表10に示す。尚、表9において数値が記載されていない場合は、条件を付与しなかったことを意味する。
導電性ゴム組成物の種類、研磨条件を変更した以外は、製造例T2と同様にして、弾性部材を得た。得られた弾性部材に、紫外線照射により処理を行い。帯電部材T16及びT17を得た。紫外線照射には、紫外線の照射には低圧水銀ランプ(ハリソン東芝ライティング(株)製)を用い、254nmの波長の紫外線を積算光量が9000mJ/cm2になるように照射した。帯電部材物性値の評価結果を表10に示す。
導電性ゴム組成物の種類、研磨条件、弾性部材、熱風循環乾燥機加熱条件、電子線照射条件を、各々表9に示す条件に変更した以外は、製造例T2と同様にして帯電部材T18及びT19を作製した。帯電部材物性値の評価結果を表10に示す。
〔帯電部材の電気抵抗〕
図5は帯電部材の電気抵抗値の測定装置である。導電性基体1の両端に軸受け33により荷重をかけて、帯電部材5を、電子写真感光体と同じ曲率の円柱形金属39に、平行になるように当接させる。この状態で、モータ(不図示)により円柱形金属39を回転させ、当接した帯電部材5を従動回転させながら安定化電源34から直流電圧-200Vを印加する。この時に流れる電流を電流計35で測定し、帯電部材の電気抵抗値を計算する。荷重は各4.9Nとし、金属製円柱は直径30mm、金属製円柱の回転は周速45mm/secとする。
十点平均粗さRzjis、算術平均粗さRa及び凹凸平均間隔Smは、JIS B 0601-1994表面粗さの規格に準じて測定し、表面粗さ測定器「SE-3500」(商品名、株式会社小坂研究所製)を用いて行う。十点平均粗さRzjis及び算術平均粗さRaは、帯電部材を任意に6箇所測定し、その平均値である。また、平均凹凸間隔Smは、前記任意の6点の各箇所において10点の凹凸間隔を測定し、その平均値を求め、6箇所の平均値の平均値として算出する。測定に際し、カットオフ値は0.8mm、評価長さは8mmに設定する。
測定箇所は、ローラ長手方向の中央部、中央部から両端部方向へ各45mm離れた位置、及び中央部から両端部方向へ各90mm離れた位置の、長手方向の各5箇所について、ローラ周方向の各2箇所(位相0°及び180°)の合計10か所とする。これらの各測定箇所において導電性樹脂層を500μmに亘って、20nmずつ集束イオンビーム加工観察装置(商品名:FB-2000C、日立製作所社製)を用いて、切り出し、その断面画像を撮影する。そして得られた断面画像を組み合わせ、ボウル形状の樹脂粒子の立体像を算出する。立体像から、図3で示すように最大径58と、図4で示す開口径の最小径74を算出する。また、上記立体像から、ボウル形状の樹脂粒子の任意の5点において、ボウル形状の樹脂粒子のシェルの厚さを測定する。このような測定を視野内の樹脂粒子10個について行い、得られた計100個の測定値の平均値を算出し、これらをそれぞれ、「最大径」、「開口径の最小径」及び「シェル厚さ」とする。また、シェルの厚さの測定に際しては、各々のボウル形状の樹脂粒子について、シェルの最も肉厚な部分の厚みが、最も肉薄の部分の厚みの2倍以下、すなわち、シェルの厚さが、略均一であることを確認した。
帯電部材の表面をレーザー顕微鏡(商品名:LXM5 PASCAL;カール・ツアイス(Carl Zeiss)社製)を用いて、縦0.5mm、横0.5mmの視野で観察する。レーザーを視野内のX-Y平面でスキャンさせることにより2次元の画像データを得、更に焦点をZ方向に移動させ、上記のスキャンを繰り返すことにより3次元の画像データを得る。その結果、まず、ボウル形状の樹脂粒子の開口に由来する凹部と、ボウル形状の樹脂粒子の開口のエッジに由来する凸部を有していることを確認する。更に、前記凸部54の頂点55と、前記凹部の底部56との高低差57を算出する。このような作業を視野内のボウル形状の樹脂粒子2個について行う。そして、同様の測定を帯電部材の長手方向50箇所について行い、得られた計100個の測定値の平均値を算出し、この値を「高低差」とする。
コールターカウンターマルチサイザーにより、樹脂粒子の粉体を用いて測定する。具体的には、電解質溶液100~150mlに界面活性剤(アルキルベンゼンスルホン酸塩)を0.1~5ml添加し、この液中に樹脂粒子を2~20mg添加する。樹脂粒子を懸濁した電解質液を超音波分散器で1~3分間分散処理して、コールターカウンターマルチサイザーにより100μmのアパチャーを用いて、体積を基準として粒度分布を測定する。得られた粒度分布から体積平均粒子径をコンピュータ処理により求め、これを樹脂粒子の平均粒径とする。
ISO14577に基づき、ピコデンターHM500(商品名、株式会社フィッシャー・インストルメント社製)を用いて測定した。圧子としては、基部が正方形の角錐型ダイヤモンド圧子で、頂点を挟む対面角度が136°である圧子(ビッカース角錐)を用いた。測定は、長手方向の中央部及び両端部(中央部から両端方向へ各90mmの位置)において行い、平均値を本発明の復元速度とする。
{押し込み工程}
・最大押し込み深さ=10μm
・押し込み時間=20秒
尚、最大押し込み深さまで押し込むことが可能なように、最大荷重Fmaxは十分大きな値とする必要があり、本測定では10mNとした。
・最小荷重=0.005mN
・除荷時間=1秒
尚、除荷は圧子の最小荷重に到達するまで行った。
復元速度v=L/0.1
[条件2]所定の深さtμmにおける復元速度の測定
・最大押し込み深さ(所定の深さt)=20、30、50、100μm
・押し込み時間=20秒
尚、最大押し込み深さまで押し込むことが可能なように、最大荷重は十分大きな値とする必要があり、本測定では300mNとした。
・最小荷重=0.005mN
・除荷時間=(最大押し込み深さ)/10sec
除荷は圧子の最小荷重に到達するまで行った。除荷時間は、押し込み工程の最大押し込み深さにより決定され、例えば、最大押し込み深さt=20μmの場合は、除荷時間は2秒となる。これは、条件1と条件2の除荷速度を同一にするためである。弾性変形に対する復元速度vの算出は、条件1と同様にして行った。
図6に示す構成を有する画像形成装置であるキヤノン(株)製モノクロレーザープリンタ(「LBP6300」(商品名))を、370mm/secのプロセススピードに改造し、更に、外部より、帯電部材に電圧を印加した。印加する電圧は、交流電圧として、ピークピーク電圧(Vpp)が1600V、周波数(f)が1350Hz、直流電圧(Vdc)が-560Vをとした。画像の解像度は、600dpiで出力した。なお、プロセスカートリッジとして、上記プリンタ用のプロセスカートリッジを用いた。
(a)当該横線画像出力開始直後から1千枚印字する間の当該横線画像(表14における評価1)、
(b)3千枚耐久使用後であって2日目の画出し試験開始直後から1千枚印字する間の当該横線画像(表における評価2)、
(c)6千枚耐久使用後であって3日目の画出し試験開始直後から1千枚印字する間の当該横線画像(表14における評価3)、及び、
(d)9千枚耐久使用後であって4日目の画出し試験開始直後から1千枚印字する間の当該横線画像(表14における評価4)
で行った。
トナーと帯電部材の組み合わせを表13に示すように変更した以外は、実施例1と同様にして評価を行った。結果を表13に示す。
トナーと帯電部材の組み合わせを表13に示すように変更した以外は、実施例1と同様にして評価を行った。結果を表13に示す。いずれの比較例においても、縦スジ画像が目立ち、画質の低下が認められた。
2 導電性弾性層
3 導電性樹脂層
4 電子写真感光体
5 帯電部材(帯電ローラ)
10 クリーニング部材
51 ボウル形状の樹脂粒子の開口
52 ボウル形状脂粒子の開口に由来する凹部
53 ボウル形状の樹脂粒子の開口のエッジ
54 ボウル形状の樹脂粒子の開口のエッジに由来する凸部
55 ボウル形状の樹脂粒子の開口のエッジに由来する凸部の頂点
56 ボウル形状の樹脂粒子の開口に由来する凹部の底部
57 高低差
58 ボウル形状の樹脂粒子の最大径
61 ボウル形状の樹脂粒子
71 開口部
72 開口部に丸みのある凹部
74 開口部の最小径
Claims (5)
- 感光体と、該感光体を帯電部材によって帯電するための帯電手段と、帯電された該感光体の表面に静電潜像を形成するための露光手段と、静電潜像が形成された該感光体にトナーを供給してトナー像を該感光体の表面に形成するための現像手段と、該帯電手段の前に、残留トナーを回収するためのクリーニング手段とを有する画像形成装置であって、
該帯電部材は、導電性基体と導電性樹脂層を有し、
該導電性樹脂層は、結着樹脂Cとボウル形状の樹脂粒子とを含み、
該帯電部材の表面は、該ボウル形状の樹脂粒子の開口に由来する凹部と、該ボウル形状の樹脂粒子の開口のエッジに由来する凸部とを有し、
該トナーは、結着樹脂T及び着色剤を含有するトナー粒子と、無機微粒子とを含有するトナーであって、
該無機微粒子がシリカ微粒子であり、
該トナーは、該シリカ微粒子をトナー粒子100質量部あたり0.40質量部以上1.50質量部以下含有し、
該シリカ微粒子は、シリカ原体100質量部に対して、15.0質量部以上40.0質量部以下のシリコーンオイルによって処理されており、該シリコーンオイルの炭素量基準の固定化率(%)が70%以上であり、
X線光電子分光装置(ESCA)により求めた、該トナーの表面の該シリカ微粒子による被覆率X1が50.0面積%以上75.0面積%以下であり、該シリカ微粒子による理論被覆率をX2としたとき、下記式1で示される拡散指数が下記式2を満足するトナーであることを特徴とする画像形成装置。
(式1)拡散指数=X1/X2
(式2)拡散指数≧-0.0042×X1+0.62 - 前記ボウル形状の樹脂粒子が、開口部を有し、且つ、シェルによって画定された丸みのある凹部を有する樹脂粒子であることを特徴とする請求項1に記載の画像形成装置。
- 前記帯電部材の表面の十点平均粗さRzjisが、15μm以上75μm以下であり、且つ、前記帯電部材の表面の算術平均粗さRaが3.0μm以上7.0μm以下であることを特徴とする請求項1または2に記載の画像形成装置。
- 前記帯電部材の復元速度が、帯電部材の表面から内部方向に向かって小さくなっていることを特徴とする請求項1乃至3のいずれか一項に記載の画像形成装置。
- 前記帯電手段、前記感光体及び前記クリーニング手段を一体に支持し、請求項1乃至4のいずれか一項に記載の画像形成装置から着脱可能に構成されていることを特徴とするプロセスカートリッジ。
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JP2015523756A JP6165249B2 (ja) | 2013-06-27 | 2013-06-27 | 画像形成装置 |
PCT/JP2013/067712 WO2014207871A1 (ja) | 2013-06-27 | 2013-06-27 | 画像形成装置及びプロセスカートリッジ |
CN201380077822.3A CN105339848B (zh) | 2013-06-27 | 2013-06-27 | 图像形成设备和处理盒 |
US14/315,686 US9291936B2 (en) | 2013-06-27 | 2014-06-26 | Image-forming apparatus with electro-conductive resin layer having resin particles and process cartridge |
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