JP5387177B2 - Method for producing toner for developing electrostatic image, toner for developing electrostatic image, and image forming method - Google Patents

Description

  The present invention relates to a method for producing an electrostatic charge image developing toner, an electrostatic charge image developing toner produced by the production method, and an image forming method using the electrostatic charge image developing toner.

  Recently, in the field of image forming technology using electrophotography such as copying machines and printers, with the progress of digital technology, a minute dot image of 1200 dpi (dpi; the number of dots per 2.54 cm) level is accurately reproduced. Image forming technology has been demanded.

  In order to accurately reproduce such a minute dot image, a reduction in the diameter (for example, a particle diameter of 4.0 to 7.0 μm) of an electrostatic charge image developing toner (hereinafter also simply referred to as toner) has been studied and manufactured. A so-called polymerized toner capable of applying various controls in the process has been attracting attention.

  It is known that a polymerized toner is produced by a production method in which a dispersion having at least resin particles and a colorant is aggregated and fused.

  In this toner production method, it is disclosed that an alkali metal hydroxide (sodium hydroxide) is used in the step of stopping aggregation (for example, see Patent Document 1).

JP 2000-122344 A

  However, in the toner manufacturing method in which a dispersion having at least resin particles and a colorant is agglomerated and fused, if sodium hydroxide is used in the step of stopping aggregation, fine particles are formed simultaneously with the formation of the toner particles. Fine particles will be mixed inside. When a large number of sheets are printed by the image forming method using the cleaning blade using the toner in which the fine particles are mixed, there is a problem that fog due to a cleaning defect occurs in the print.

  An object of the present invention is to transfer the surface (photosensitive member surface, intermediate transfer member surface, two-sided surface) even if a large number of sheets are printed by loading the toner in an image forming apparatus of an image forming method in which the transfer residual toner is cleaned by a cleaning blade method. It is an object of the present invention to provide a toner manufacturing method, a toner and an image forming method capable of continuously obtaining a high-quality printed image without causing toner filming on the surface of the next transfer member.

  The above object of the present invention can be achieved by adopting the following configuration.

1. In a method for producing a toner for developing an electrostatic charge image having a step of producing toner base particles by aggregating and fusing at least resin particles and a colorant,
After aggregating the resin particles and the colorant in the step of preparing the toner base particles,
A method for producing an electrostatic charge image developing toner, comprising adding a compound represented by the following general formula ( 2):

In the formula, the heterocyclic structure represented by a dotted line is a cyclic structure having a C ₄ or C ₅ nitrogen atom, and R ₄ represents H, a C _{1 to} C ₃ alkyl group or an alkanol group.

2. Formula (2) is a compound represented by, after by aggregating the resin particles colorant, manufacturing method of the electrostatic image developing toner according to the 1, characterized in that they are added together.

  3. An electrostatic image developing toner produced by the method for producing an electrostatic image developing toner described in 1 or 2 above.

  4). The toner for developing an electrostatic charge image described in 3 above is loaded, and after the toner image formed by the toner for developing an electrostatic charge image is transferred to a transfer material, the residual transfer toner that is not transferred is cleaned with a cleaning blade. An image forming method.

  The toner production method, toner, and image forming method of the present invention have excellent effects that a high-quality print image can be continuously obtained without fogging even when a large number of sheets are printed.

FIG. 3 is a schematic cross-sectional view showing an example of a color image forming apparatus using toner produced by the toner production method of the present invention. It is the schematic which shows an example of the cleaning means of a photoconductor. FIG. 3 is a schematic diagram illustrating an example of a cleaning unit for an intermediate transfer member. It is the schematic which shows an example of the cleaning means of a secondary transfer member.

  In a toner manufacturing method in which a dispersion having at least resin particles and a colorant is agglomerated and fused, if sodium hydroxide is used as an agglomeration stopper in the step of aggregating, sodium hydroxide is electrostatically applied to the aggregate particle surface. Since the mechanical repulsion is imparted, the aggregation between the aggregate particles can be stopped.

  When the present inventors stop the aggregation using sodium hydroxide, the sodium hydroxide penetrates into the inside of the aggregate particles obtained by aggregating and fusing the dispersion having the resin particles and the colorant, Electrostatic repulsion is also generated inside the aggregate particles, and a part of the aggregate particles is liberated, and it is thought that the liberated particles form fine particles, and the aggregation is stopped without penetrating into the aggregate particles. The aggregation terminator which can be used was examined.

  As a result of various studies on the aggregation terminator having such characteristics, the use of an aggregation terminator with a molecular size large enough to adsorb on the surface of the aggregate particle and not penetrate into the inside of the aggregate particle prevents the generation of fine particles. I found that I could do it.

  The compound having a molecular size large enough not to penetrate into the aggregate particles is preferably one having a major axis of 5 to 10 mm and a minor axis of 5 to 20 mm. Further, the major axis is preferably 5 to 8 mm and the minor axis is 5 to 15 mm.

  In addition, the molecular size of the aggregation terminator is “HGS molecular structure model” (Hinomoto Synthetic Resin Manufacturing Co., Ltd.), creating a molecular model of the corresponding structure, and the longest distance between atoms (major axis), It is a value obtained by measuring the length of the shortest distance between atoms (minor axis) and converting it to the distance in the actual molecule.

  If the molecular size of the aggregation terminator is too small, the aggregation terminator penetrates into the aggregate particles and generates fine particles. This is undesirable. If the molecular size of the aggregation terminator is too large, the aggregation terminator is washed in the washing process. It is difficult to clean the toner, and the aggregation terminator remains on the surface of the toner particles, causing abnormal charging.

The median diameter (D ₅₀ ) of the toner according to the present invention on a volume basis is preferably 3.0 to 8.0 μm. More preferably, it is 4.0-7.0 micrometers.

The toner is obtained by processing the small-diameter external additive to toner base particles, the median diameter (D ₅₀₎ in the volume-based median diameter (D ₅₀₎ and the toner base particles in the volume-based toner is substantially the same .

The volume-based median diameter (D ₅₀ ) is a toner particle diameter corresponding to a count number (cumulative value) corresponding to 50% of the total particle number when a constant volume of toner is counted in order of increasing or decreasing particle diameter. Is.

  The toner according to the present invention preferably has a coefficient of variation (hereinafter also referred to as CV value) of 20% or less in the volume-based particle size distribution of the toner constituting the toner. Use of a toner having a variation coefficient of 20% or less and a sharp particle size distribution is preferable because a high-definition character image can be obtained. The coefficient of variation in the toner volume-based particle size distribution is calculated from the following equation.

Coefficient of variation (CV value) (%) = (S2 / Dn) × 100
(In the formula, S2 represents the standard deviation in the volume-based particle size distribution, and Dn represents the median diameter (D ₅₀ ) based on the volume).
The median diameter (D ₅₀ ) and coefficient of variation (CV value) of the toner according to the present invention are set in “Coulter Multisizer 3” (manufactured by Beckman Coulter, Inc.) and a computer system for data processing (Beckman Coulter, Inc.). It can be measured and calculated using a device connected to the product.

  As a measurement procedure, 0.02 g of toner is blended with 20 ml of a surfactant solution (for example, a surfactant solution obtained by diluting a neutral detergent containing a surfactant component 10 times with pure water for the purpose of dispersing the toner). After that, ultrasonic dispersion is performed for 1 minute to prepare a toner dispersion. This toner dispersion is poured into a beaker containing the electrolyte solution “ISOTONII” (manufactured by Beckman Coulter, Inc.) in the sample stand with a pipette until the measurement concentration becomes 8% by mass, and the measuring machine count is increased to 2500 pieces. Set and measure. The aperture diameter of the Coulter Multisizer is 50 μm.

  The toner according to the present invention preferably has an average circularity of 0.916 to 0.955. Here, the circularity of the toner is calculated from the following equation.

Circularity = (perimeter of a circle having the same projection area as the particle image) / (perimeter of the particle projection image)
The average circularity is a value calculated by dividing the sum of the circularity of individual toner particles by the total number of particles.

  As an apparatus for measuring the circularity of the toner, for example, “FPIA-2100” (manufactured by Sysmex Corporation) can be mentioned. In the measurement using FPIA-2100, the toner is blended with an aqueous solution containing a surfactant, and after ultrasonic dispersion treatment is performed for 1 minute to disperse the toner, measurement is performed using “FPIA-2100”. Measurement conditions are set to the HPF (high magnification imaging) mode and the number of HPF detections is set to an appropriate density of 3000 to 10,000.

  The fine particles referred to in the present invention refer to particles having a particle size smaller than that of the toner.

  The fine particles are obtained by measuring a dispersion of toner base particles containing fine particles with an image analysis apparatus “FPIA” (manufactured by Sysmec).

  The mixing amount of the fine particles mixed in the toner base particles is obtained by measuring the number of 0.6 to 2.0 μm that can be measured by “FPIA”.

  The amount of fine particles mixed in the toner base particles is preferably 1.0% by number or less. The occurrence of toner filming can be prevented by setting the amount of fine particles to be 1.0% by number or less.

[Toner Production Method]
A method for producing the toner of the present invention will be described.

  The method for producing a toner of the present invention is a method in which at least resin particles and a colorant are agglomerated and fused, and is characterized in that aggregation is stopped using a specific aggregation terminator.

  Examples of the aggregation terminator used in the present invention include compounds represented by general formula (1) and general formula (2).

  Compound represented by general formula (1)

In the formula, R ₁ represents a C _{2 to} C ₅ alkyl group or alkanol group R ₂ represents a C _{2 to} C ₅ alkyl group or alkanol group R ₃ represents H, C _{2 to} C ₅ alkyl group or alkanol group.

  Compound represented by general formula (2)

In the formula, the heterocyclic structure represented by a dotted line is a cyclic structure having a C ₄ or C ₅ nitrogen atom, and R ₄ represents H, a C _{1 to} C ₃ alkyl group or an alkanol group.

  As preferred compounds of the general formula (1), compounds (1) to (14) can be mentioned.

  As preferred compounds of the general formula (2), compounds (15) to (21) can be mentioned.

  Next, the method for producing the toner of the present invention and the members used for producing the toner will be described.

[Toner Production Method]
The method for producing the toner of the present invention is a method through the following steps.
(1) A step of preparing a dispersion of toner base particles containing a resin and a colorant (2) A step of cooling the toner base particle dispersion (3) A solid solution of toner base particles from the cooled toner base particle dispersion Step of separating and washing the toner base particles (4) Step of drying the washed toner base particles (5) Step of adding an external additive to the dried toner base particles The “process for producing particles containing a colorant” will be described. This step is a step of aggregating and fusing the resin particles and the colorant in an aqueous medium to produce toner base particles containing the resin and the colorant, and includes the following steps. That is,
(A) A step of dissolving a wax in a radical polymerizable monomer as required to prepare a monomer solution (b) A polymerization step of polymerizing a radical polymerizable monomer solution to produce resin particles (c) Obtained in a polymerization step The resin particles and the colorant are aggregated and fused to form toner base particles.

  The polymerization reaction for producing the resin particles is performed by the following procedure, for example. A monomer solution in which wax is dissolved is added to an aqueous medium (an aqueous solution of a surfactant and a radical polymerization initiator) containing a surfactant having a critical micelle concentration (CMC) or less, and mechanical energy is added to the monomer solution. Droplets are formed. Next, a water-soluble radical polymerization initiator is added to advance the polymerization reaction in the droplets. It is also possible to carry out the polymerization by containing an oil-soluble polymerization initiator in the monomer droplet. Examples of the mechanical energy applying means for forming droplets of the monomer solution include a homomixer, a manton gourin, and an ultrasonic vibration device.

  The wax that can be used in the production of the resin particles in this step is not particularly limited, and if not necessary, it may not be added. Preferably, low-molecular-weight polyethylene or polypropylene, olefinic wax such as a copolymer of polyethylene and other olefinic polymer, paraffin wax, behenyl behenate or montanate, glycerin ester, stearyl stearate, etc. Ester wax having a group, plant wax such as carnauba wax, ketone wax having a long chain alkyl group such as distearyl ketone, silicone wax having an alkyl group, higher fatty acid wax such as stearic acid, long Long-chain fatty acid polyhydric alcohol waxes such as chain fatty acid alcohol waxes and pentaerythritol and partial ester waxes thereof, higher fatty acid amide waxes such as oleic acid amide and stearic acid amide, and the like. Among these, good fixability is obtained by using a wax having a melting point of 100 ° C. or less, more preferably 40 to 90 ° C., and particularly preferably 50 to 80 ° C.

  In addition, known cationic surfactants, anionic surfactants, nonionic surfactants, and amphoteric surfactants are used as emulsifiers used when preparing droplets of the monomer solution. Two or more types can be used in combination.

  Examples of the cationic surfactant include dodecyl ammonium chloride, dodecyl ammonium bromide, dodecyl trimethyl ammonium bromide, dodecyl pyridinium chloride, dodecyl pyridinium bromide, hexadecyl trimethyl ammonium bromide and the like.

  Examples of the anionic surfactant include aliphatic soaps such as sodium stearate and sodium dodecanoate, sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, and sodium laurate.

  Further, examples of the nonionic surfactant include dodecyl polyoxyethylene ether, hexadecyl polyoxyethylene ether, nonylphenyl polyoxyethylene ether, lauryl polyoxyethylene ether, sorbitan monooleate polyoxyethylene ether, monodecanoyl Sucrose etc. are mentioned.

  Examples of amphoteric surfactants include N-alkylnitrilotriacetic acid, N-alkyldimethyl N oxide, α-trimethylammonio fatty acid, N-alkyl-β-aminopropionate, N-alkyl-β-iminopropionate, N -Alkyloxymethyl-N, N-diethyl N oxide, N-alkyl-N, N-diaminoethylglycine hydrochloride, 2-alkyl imidazoline derivatives, aminoethyl imidazoline organic acid salt, N-alkyl sulfo N oxide, N-alkyl Taurine salt can be raised.

  Next, the monomer used for production of the resin particles will be described. In the present invention, resin particles containing wax are prepared by adding a monomer having a polar group and another monomer to advance polymerization. When producing resin particles using a plurality of types of monomers, the monomers may be added separately, or a plurality of monomers may be added in advance after mixing. Further, it is possible to change the monomer composition during the monomer addition.

  In producing the resin particles, it is possible to add a certain amount of an emulsifier in order to advance the polymerization reaction more reliably. Further, the timing for adding the polymerization initiator may be before the monomer addition, at the same time as the monomer addition, after the monomer addition, or by an addition method combining these.

  It is also possible to add components other than wax, such as colorants and charge control agents, to produce resin particles containing these components, and perform the polymerization reaction after dissolving the colorant in the monomer or wax. It is also possible.

  Examples of the monomer having an acidic polar group include monomers having a carboxyl group such as acrylic acid, methacrylic acid, maleic acid, fumaric acid and cinnamic acid, and monomers having a sulfonic acid group such as sulfonated styrene. It is done.

  Examples of the monomer having a basic polar group include monomers containing nitrogen-containing heterocycles such as aminostyrene and quaternary salts thereof, vinylpyridine and vinylpyrrolidone, dimethylaminoethyl acrylate, diethylaminoethyl methacrylate and the like. (Meth) acrylic acid ester monomers having amino groups, and (meth) acrylic acid ester monomers having quaternized ammonium salts of these amino groups, acrylamide, N-propylacrylamide, N, N-dimethylacrylamide, N , N-dipropylacrylamide, N, N-dibutylacrylamide, acrylic acid amide and the like.

  Furthermore, as other monomers, styrenes such as styrene, methylstyrene, chlorostyrene, dichlorostyrene, p-tert-butylstyrene, pn-butylstyrene, pn-nonylstyrene, methyl acrylate, acrylic acid Examples include (meth) acrylic acid esters such as ethyl, propyl acrylate, n-butyl acrylate, isobutyl methacrylate, hydroxyethyl methacrylate, and ethylhexyl methacrylate.

  In the present invention, methacrylic acid is suitably used as the monomer having a polar group, and styrene, acrylic acid ester, and methacrylic acid ester are suitably used as other monomers.

  These monomers can be used alone or in combination, but it is preferable to select the monomers so that the glass transition temperature of the resin is 40 to 80 ° C. By setting the glass transition temperature of the resin within the above range, the storage stability of the toner can be ensured and the fixing temperature can be set widely.

  As polymerization initiators, persulfates such as potassium persulfate, sodium persulfate and ammonium persulfate, redox initiators combining these persulfates as a component with a reducing agent such as acidic sodium sulfite, hydrogen peroxide, Water-soluble polymerization initiators such as 4,4'-azobiscyanovaleric acid, t-butyl hydroperoxide, cumene hydroperoxide, etc., and reducing agents such as ferrous salts with these water-soluble polymerization initiators as one component The combined redox initiator, benzoyl peroxide, 2,2'-azobisisobutyronitrile and the like can be mentioned.

  Moreover, it is also possible to use a chain transfer agent when producing the resin particles. Examples of the chain transfer agent include t-dodecyl mercaptan, n-octyl mercaptan, 2-mercaptoethanol, diisopropylxanthogen and the like. The chain transfer agents can be used alone or in combination of two or more. Further, the addition amount of the chain transfer agent is preferably 5% by mass or less with respect to the total monomer amount.

  The size of the resin particles is preferably in the range of 50 to 3000 nm as an average particle size, more preferably 100 to 1000 nm, and particularly preferably 100 to 500 nm. As a result, it becomes easy to control the agglomeration speed at the time of toner production, and it becomes easy to produce a uniform toner. In addition, when the size of the resin particles is within the above range, a small-diameter toner is easily obtained, and high-resolution image formation is promoted. The size of the resin particles can be measured using a particle size distribution measuring device, similar to the measurement of the wax particles described above. For example, the microtrack particle size distribution measuring device “UPA” using a laser diffraction scattering method can be used. Examples include commercially available particle size distribution measuring devices such as Nikkiso Co., Ltd.

  In the particle formation step subsequent to the polymerization step, particles are formed by aggregating and fusing the resin particles and the colorant. One of the typical methods for forming particles by aggregating and fusing is a “salting out / fusing method”. In this method, resin particles obtained by polymerizing monomers to form resin particles are aggregated using a colorant and a metal salt to grow particles. And when it grows to the desired particle diameter, an aggregation stop agent is added to stop the particle growth, and further, heating for controlling the particle shape is continued as necessary. In the present invention, particle growth is performed by mixing resin particles having different polarities and toner base particles, instead of the “salting out / fusion method” using a metal salt. And when it grows to a desired particle diameter, an aggregation terminator is added to stop the particle growth, and further, heating for controlling the particle shape is continued as necessary.

  In the particle forming step, in addition to the resin particles and the colorant, an internal additive such as a wax or a charge control agent can be aggregated and fused in the form of particles.

  The “aqueous medium” in the particle forming step refers to a material whose main component (50% by mass or more) is water. Examples of components other than water include organic solvents that dissolve in water, such as methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, and tetrahydrofuran.

  The dispersion of the colorant can be prepared by dispersing the colorant in an aqueous medium. The dispersion treatment of the colorant is performed in a state where the surfactant concentration is set to a critical micelle concentration (CMC) or more in water. The disperser used for the dispersion treatment of the colorant is not particularly limited, but preferably an ultrasonic disperser, a mechanical homogenizer, a pressure disperser such as a manton gorin or a pressure homogenizer, a sand grinder, a Getzmann mill, a diamond fine mill, or the like. Examples thereof include a medium type disperser. Further, examples of the usable surfactant include the same surfactants as those used for forming the fine resin particles described above, but it is preferable to use an amphoteric surfactant. In the present invention, the colorant may be surface-modified. In the surface modification method of the colorant, the colorant is dispersed in a solvent, the surface modifier is added to the molecular weight solution, and the system is reacted by raising the temperature. After completion of the reaction, the colorant is filtered off, washed and filtered with the same solvent, and dried to obtain a colorant treated with the surface modifier.

  Aggregation / fusion is performed by adding an acid such as hydrochloric acid to water in which resin particles and a colorant are present to bring the pH to the acid side, and then heating to a temperature above the glass transition point of the resin particles. At the same time as the agglomeration proceeds, fusion is performed. When a desired particle size is obtained by fusing, the growth of the particles is stopped by adding any of the compounds represented by the general formula (1) or the general formula (2) (aggregation terminator). . Then, the shape of the toner base particles is controlled by continuing heating as necessary.

  The addition of the aggregation terminator is preferably a method in which the resin particles and the colorant are aggregated and then added together.

  The addition amount of the aggregation terminator is preferably 1 to 10% by mass with respect to the mass of the toner base particles. By setting the addition amount of the aggregation stopper within the above range, the generation of fine particles can be prevented, and unnecessary aggregation stopper can be satisfactorily washed and removed.

  Next, (2) “step of cooling the toner base particle dispersion” will be described. This step is a step of cooling the dispersion of the toner base particles produced in the above-described step, and a rapid cooling process is performed at a cooling rate of 1 to 20 ° C./min. Examples of the cooling treatment method used in this step include a method of cooling by introducing a refrigerant from the outside of the reaction vessel, and a method of cooling by directly introducing cold water into the reaction system.

  Next, (3) “step of solid-liquid separating the toner base particles from the cooled toner base particle dispersion and washing the toner base particles” will be described. In this solid-liquid separation / washing process, a process for solid-liquid separating the toner base particles from the toner base particle dispersion liquid cooled to a predetermined temperature in the above-described process, and a collective aggregate of toner base particles called a toner cake by solid-liquid separation It consists of a process of washing the body. By cleaning the toner cake, deposits such as a surfactant and a flocculant adhering to the surface of the toner base particles are removed.

  Examples of the solid-liquid separation method for the toner base particle dispersion include a centrifugal separation method, a vacuum filtration method using Nutsche and the like, a filtration method using a filter press and the like. By repeatedly performing the solid-liquid separation / washing process a plurality of times, the deposits on the surface of the toner base particles can be more reliably removed.

  Next, (4) “step of drying washed toner base particles” will be described. This step is a step of drying the toner cake that has undergone the final cleaning process. Specific drying devices used in this process include spray dryer, vacuum freeze dryer, vacuum dryer, stationary shelf dryer, mobile shelf dryer, fluidized bed dryer, rotary dryer And a stirring type dryer.

  The moisture content of the toner base particles after the drying treatment is 5% by mass or less, preferably 2% by mass or less, as measured by the Karl Fischer method. Examples of the moisture measuring device by the Karl Fischer method include an automatic moisture measuring device “AQS-724” (manufactured by Hiranuma Sangyo Co., Ltd.). The conditions for measuring the moisture content are, for example, a vaporization temperature of 110 ° C., and a vaporization time. Set to 25 seconds and measure.

  Next, (5) “step of adding an external additive to dried toner base particles” will be described. In this step, an external additive is added to the dried toner base particles as necessary to make the toner base particles usable for image formation. Examples of the apparatus for adding and mixing the external additive include mechanical mixing apparatuses such as a Henschel mixer and a coffee mill.

  Next, constituent materials of the toner according to the present invention will be described.

  The resin for the binder resin used in the toner according to the present invention is not particularly limited, and a known resin is used. Preferably, a copolymer of styrene such as polystyrene or polyvinyltoluene, or a substituted product thereof; styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester Copolymer, Styrene-acrylonitrile copolymer, Styrene-vinyl methyl ether copolymer, Styrene-vinyl ethyl ether copolymer, Styrene-vinyl methyl ketone copolymer, Styrene-butadiene copolymer, Styrene-isoprene copolymer Styrene copolymers such as coalescence, styrene-acrylonitrile-indene copolymer; phenol resin, natural modified phenolic resin, natural resin modified maleic acid resin, acrylic resin, methacrylic resin, polyvinyl acetate resin, silicone resin, polyester resin, Polyurethane resins, polyamide resins, furan resins, epoxy resins, xylene resins, polyvinyl butyral resins, terpene resins, coumarone-indene resins, and petroleum resins. Of these, polyester resins and styrene copolymer resins are particularly used.

  In addition, as a monomer combined with the styrene monomer of the styrenic copolymer, acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate , Monocarboxylic acids having a double bond such as methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide or the like; maleic acid, butyl maleate, malee Dicarboxylic acids having a double bond such as methyl acid and dimethyl maleate or substituted products thereof; vinyl esters such as vinyl acetate and vinyl benzoate; ethylene-based olefins such as ethylene, propylene and butene; Ketone, vinyl ketones such as vinyl hexyl ketone, vinyl methyl ether, vinyl ethyl ether, vinyl ethers such as vinyl isobutyl ether. In the case of forming a styrene copolymer, these vinyl monomers are used alone or in combination of two or more.

  In addition, the toner binder resin may be a mixture of two or more of the above-described resins, or may form a crosslinked structure via a crosslinking agent. As the crosslinking agent, a compound having two or more polymerizable double bonds is used. Preferably aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; carboxylic acid ester compounds having two or more double bonds such as ethylene glycol dimethacrylate, ethylene glycol diacrylate and 1,3-butanediol dimethacrylate; divinylaniline , Divinyl ether, divinyl sulfide, divinyl sulfone and other divinyl compounds; compounds having three or more vinyl groups, and the like. These can be used alone or in combination of two or more.

  Examples of the colorant that can be used in the present invention include the following.

  As the black colorant, for example, carbon black such as furnace black, channel black, acetylene black, thermal black, lamp black, or a magnetic material such as magnetite or ferrite can be used.

  Examples of the colorant for magenta or red include C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48; 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 166, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. And CI Pigment Red 222.

  Examples of the colorant for orange or yellow include C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. Pigment Yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. And CI Pigment Yellow 138.

  Examples of pigments for green or cyan include C.I. I. Pigment blue 15, C.I. I. Pigment blue 15; 2, C.I. I. Pigment blue 15; 3, C.I. I. Pigment blue 15; 4, C.I. I. Pigment blue 16, C.I. I. Pigment blue 60, C.I. I. Pigment blue 62, C.I. I. Pigment blue 66, C.I. I pigment green 7 etc. are mentioned.

  These colorants can be used alone or in combination of two or more as required. The addition amount of the colorant is set in the range of 1 to 30% by mass, preferably 2 to 20% by mass with respect to the total mass of the toner.

  A charge control agent can be added to the toner according to the present invention as necessary. Specific examples of charge control agents include nigrosine dyes, metal salts of naphthenic acid or higher fatty acids, benzylic acid derivative metal salts or metal complexes thereof, alkoxylated amines, quaternary ammonium salt compounds, azo metal complexes, Examples include salicylic acid metal salts and metal complexes thereof. Examples of the contained metal include Al, B, Ti, Fe, Co, and Ni. Among these, a metal complex compound of a benzylic acid derivative is particularly preferable.

  The addition amount of the charge control agent is preferably in the range of 0.1 to 20.0% by mass with respect to the total mass of the toner.

  A so-called external additive can be added to the toner according to the present invention for the purpose of improving fluidity, chargeability, and cleaning property. These external additives are not particularly limited, and various inorganic fine particles, organic fine particles, and lubricants can be used.

  As inorganic fine particles, for example, silica, titania, alumina, strontium titanate fine particles and the like can be preferably used. These inorganic fine particles may be hydrophobized as necessary. Specific examples of the silica fine particles include commercially available products R-805, R-976, R-974, R-972, R-812, R-809 manufactured by Nippon Aerosil Co., Ltd., HVK-2150, H- manufactured by Hoechst. 200, commercial products TS-720, TS-530, TS-610, H-5, MS-5 and the like manufactured by Cabot Corporation.

  As titania fine particles, for example, commercially available products T-805 and T-604 manufactured by Nippon Aerosil Co., Ltd., commercially available products MT-100S, MT-100B, MT-500BS, MT-600, MT-600SS, JA- 1. Commercial products TA-300SI, TA-500, TAF-130, TAF-510, TAF-510T manufactured by Fuji Titanium Co., Ltd. Commercial products IT-S, IT-OA, IT-OB, IT- manufactured by Idemitsu Kosan Co., Ltd. OC etc. are mentioned.

  Examples of the alumina fine particles include commercial products RFY-C and C-604 manufactured by Nippon Aerosil Co., Ltd. and commercial products TTO-55 manufactured by Ishihara Sangyo Co., Ltd.

  As the organic fine particles, spherical organic fine particles having a number average primary particle diameter of about 10 to 2000 nm can be used. Preferably, a homopolymer such as styrene or methyl methacrylate or a copolymer thereof can be used.

  The addition amount of these external additives is preferably 0.1 to 10.0% by mass with respect to the total mass of the toner. As a method for adding the external additive, various known mixing apparatuses such as a Turbuler mixer, a Henschel mixer, a Nauter mixer, and a V-type mixer can be used.

  The toner according to the present invention may be used with a lubricant added for the purpose of improving the cleaning property and the transfer property, if necessary. Examples of lubricants include, for example, salts of zinc stearate, aluminum, copper, magnesium, calcium, zinc oleate, salts of manganese, iron, copper, magnesium, etc., zinc palmitate, copper, magnesium, calcium, etc. And salts of higher fatty acids such as salts, zinc of linoleic acid, salts of calcium, etc., zinc of ricinoleic acid, salts of calcium, etc.

  The addition amount of these lubricants is preferably 0.1 to 10.0% by mass with respect to the total mass of the toner. As a method for adding the lubricant, various known mixing apparatuses such as a Turbuler mixer, a Henschel mixer, a Nauter mixer, and a V-type mixer can be used.

  The toner according to the present invention can be used as a black toner or a color toner.

(Developer)
The toner according to the present invention can be used as a one-component developer or a two-component developer. When used as a one-component developer, a non-magnetic one-component developer or a magnetic one-component developer containing about 0.1 to 0.5 μm of magnetic particles in the toner can be used. be able to. However, the effect of the present invention can be sufficiently exerted and the minute dot reproducibility can be stably exhibited over a long period of time when the toner is mixed with a carrier and used as a two-component developer.

  In this case, conventionally known materials typified by iron-containing magnetic particles such as iron, ferrite, and magnetite can be used as the magnetic particles of the carrier, but ferrite particles or magnetite particles are particularly preferable. The magnetic particles preferably have a volume average particle diameter of 15 to 100 μm, more preferably 20 to 80 μm.

  The volume average particle diameter of the carrier can be measured by a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by Sympathetic).

  The carrier is preferably a coating carrier in which magnetic particles are further coated with a resin, or a so-called resin dispersion type carrier in which magnetic particles are dispersed in a resin. The resin composition for coating is not particularly limited, and for example, olefin resin, styrene resin, styrene-acrylic resin, silicone resin, ester resin, or fluorine-containing polymer resin is used. The resin for constituting the resin-dispersed carrier is not particularly limited, and known resins can be used. For example, styrene-acrylic resin, polyester resin, fluorine resin, phenol resin, etc. are used. be able to.

  The mixing ratio of the carrier and the toner is preferably in the range of carrier: toner = 1: 1 to 50: 1 by mass ratio.

[Image Forming Method and Image Forming Apparatus]
The toner produced by the toner production method of the present invention is a monochrome image forming apparatus or a color image forming device that cleans toner remaining on any of the photosensitive member, the intermediate transfer member, and the secondary transfer member with a cleaning blade. It can be used by being loaded into an apparatus.

  Here, the remaining toner refers to transfer residual toner on the photosensitive member, transfer residual toner on the intermediate transfer belt, and patch image toner on the secondary transfer member.

  In a color image forming device, a patch image is formed on an intermediate transfer body for each fixed print, the reflection density of this patch image is measured by a detection sensor, and charging and developing conditions are controlled so that the density becomes a prescribed value. High quality print images are continuously obtained.

  Preferably, the patch image formed on the photosensitive member is transferred to the intermediate transfer member as it is, and the reflection density of the patch image is measured by a detection sensor installed on the periphery of the intermediate transfer member. The charging conditions and the development conditions are controlled by the reflection density of the patch image measured by the detection sensor, and a stable high-quality print image can be continuously obtained.

  After the reflection density of the patch image is measured, the patch image toner on the intermediate transfer member is cleaned by the intermediate transfer member cleaning means described below, or transferred from the intermediate transfer member to the secondary transfer member. Thereafter, the secondary transfer member is cleaned by a cleaning means.

  Hereinafter, a color image forming method and an image forming apparatus in which the toner according to the present invention is preferably used will be described.

  FIG. 1 is a schematic cross-sectional view showing an example of a color image forming apparatus using toner prepared by the toner manufacturing method of the present invention.

  The image forming apparatus GS is called a tandem type color image forming apparatus, and arranges image forming units that form yellow, magenta, cyan, and black color toner images along the moving direction of the intermediate transfer member. The color toner image formed on the image carrier of the image forming unit is transferred onto the intermediate transfer member by multiple transfer, and then transferred onto the transfer material at a time.

  In FIG. 1, a document image placed on an image reading device SC disposed at a position occupying the upper portion of the image forming device GS is scanned and exposed by an optical system, read into a line image sensor CCD, and line image sensor CCD. The analog signal photoelectrically converted by the above is subjected to analog processing, A / D conversion, shading correction, image compression processing, and the like in the image processing section, and then sent to the exposure optical system 3 as image writing means. .

  The intermediate transfer member includes a drum type and an endless belt type, both of which have similar functions. However, in the following description, the intermediate transfer member refers to the endless belt-like intermediate transfer 6. I will decide.

  In FIG. 1, four sets of process units 100 are formed on the peripheral edge of the intermediate transfer member 6 for image formation for each color of yellow (Y), magenta (M), cyan (C), and black (K). Is provided. The process unit 100 is arranged in a vertical line along the intermediate transfer body 6 as a color toner image forming unit along the intermediate transfer body 6 with respect to the rotation direction of the vertical intermediate transfer body 6 indicated by the arrows in the drawing. , K in this order.

  Each of the four sets of process units 100 has a common structure, and each includes a photosensitive drum 1, a charger 2 as a charging unit, an exposure optical system 3 as an image writing unit, a developing device 4, and an image. It comprises a photoconductor cleaning device 190 as a carrier cleaning means.

  In the photosensitive drum 1, a photosensitive layer having a layer thickness (film thickness) of about 20 to 40 μm is formed on the outer periphery of a cylindrical substrate formed of a metallic member such as aluminum having an outer diameter of about 40 to 100 mm. Is. The photosensitive drum 1 is rotated by a power from a driving source (not shown) in the direction of the arrow in a state where the substrate is grounded, for example, at a linear velocity of about 80 to 280 mm / sec, preferably 220 mm / sec.

  Around the photosensitive drum 1, an image forming unit including a charger 2 as a charging unit, an exposure optical system 3 as an image writing unit, and a developing device 4 is set as a photosensitive drum indicated by an arrow in the figure. 1 with respect to the rotation direction.

  The charger 2 as a charging unit is attached in close proximity to the photosensitive drum 1 in a direction parallel to the rotation axis of the photosensitive drum 1. The charger 2 includes a discharge wire as a corona discharge electrode that applies a predetermined potential to the photosensitive layer of the photosensitive drum 1, and performs a charging action (negative charging in the present embodiment) by corona discharge having the same polarity as the toner. A uniform potential is applied to the photosensitive drum 1.

  An exposure optical system 3 serving as an image writing means rotationally scans laser light emitted from a semiconductor laser (LD) light source (not shown) in a main scanning direction by a rotating polygon mirror (no symbol), and an fθ lens (no symbol). ), A reflection mirror (without a symbol), etc., the photosensitive drum 1 is exposed to an electrical signal corresponding to an image signal (image writing), and an electrostatic latent image corresponding to a document image is formed on the photosensitive layer of the photosensitive drum 1. Form an image.

  The developing device 4 as a developing unit is configured to supply a two-component developer of each color of yellow (Y), magenta (M), cyan (C), and black (K) charged to the same polarity as the charging polarity of the photosensitive drum 1. A developing roller 4a, which is a developer carrier formed of a cylindrical nonmagnetic stainless steel or aluminum material having a thickness of 0.5 to 1 mm and an outer diameter of 15 to 25 mm, for example, is provided. The developing roller 4a is kept in contact with the photosensitive drum 1 with a predetermined gap (for example, 100 to 1000 μm) by an abutting roller (not shown), and rotates in the same direction as the rotational direction of the photosensitive drum 1. At the time of development, a photoconductor drum is applied by applying to the developing roller 4a a DC voltage having the same polarity as the toner (negative polarity in the present embodiment) or a developing bias voltage that superimposes an AC voltage on the DC voltage. The reversal development is performed on the upper exposed portion.

The intermediate transfer member 6 has a volume resistivity of about 1.0 × 10 ^{7 to} 1.0 × 10 ⁹ Ω · cm and a surface resistivity of about 1.0 × 10 ^{10 to} 1.0 × 10 ¹² Ω / □. A semiconductive endless (seamless) resin belt is used. The resin belt is preferably a semiconductive film having a thickness of 0.05 to 0.5 mm in which a conductive material is dispersed in engineering plastics such as modified polyimide, thermosetting polyimide, ethylene tetrafluoroethylene copolymer, polyvinylidene fluoride, and nylon alloy. Can be used. In addition to this, a semiconductive rubber belt having a thickness of 0.5 to 2.0 mm in which a conductive material is dispersed in silicone rubber, urethane rubber or the like can also be used as the intermediate transfer member 6. The intermediate transfer member 6 is wound around a plurality of roller members including a tension roller 6a and a backup roller 6B facing the secondary transfer member, and is supported so as to be rotatable in the vertical direction.

  The primary transfer roller 7 as a first transfer unit for each color is made of a roller-like conductive member using foamed rubber such as silicone or urethane, for example, and the photosensitive drum 1 for each color with the intermediate transfer body 6 interposed therebetween. The transfer area is formed between the photosensitive drum 1 and the back surface of the intermediate transfer body 6 by pressing the back surface thereof. A DC constant current having a polarity opposite to that of the toner (positive polarity in the present embodiment) is applied to the primary transfer roller 7 by constant current control, and a toner image on the photosensitive drum 1 is formed by a transfer electric field formed in the transfer area. Transferred onto the intermediate transfer body 6.

  The toner image transferred onto the intermediate transfer body 6 is transferred onto the transfer material P. A detection sensor 8 for measuring the density of the patch image toner is installed on the periphery of the intermediate transfer member 6.

  In order to clean the residual toner on the intermediate transfer member 6, a cleaning device 190A is provided.

  Further, a secondary transfer device 70 is provided for cleaning the patch image toner on the secondary transfer member 7A.

  Next, an image forming process (image forming process) will be described.

  When the image recording is started, the photosensitive drum drive motor (not shown) is rotated to rotate the Y photosensitive drum 1 in the direction indicated by the arrow in the figure, and a potential is applied to the Y photosensitive drum 1 by the Y charger 2. . After the Y photosensitive drum 1 is applied with a potential, the Y exposure optical system 3 performs exposure (image writing) with an electrical signal corresponding to the first color signal, that is, the Y image data. An electrostatic latent image corresponding to a yellow (Y) image is formed on the body drum 1. The latent image is reversely developed by the Y developing device 4 to form a toner image made of yellow (Y) toner on the Y photosensitive drum 1. The Y toner image formed on the Y photosensitive drum 1 is transferred onto the intermediate transfer member 6 by a primary transfer roller 7 as a primary transfer means.

  Next, a potential is applied to the M photosensitive drum 1 by the M charger 2. After the potential is applied to the M photoconductor drum 1, the M exposure optical system 3 performs exposure (image writing) with an electrical signal corresponding to the first color signal, that is, the M image data, and the M photosensitivity. An electrostatic latent image corresponding to a magenta (M) image is formed on the body drum 1. The latent image is reversely developed by the M developing device 4 to form a toner image made of magenta (M) toner on the M photoconductor drum 1. The M toner image formed on the M photoconductor drum 1 is transferred onto the intermediate transfer body 6 by being superimposed on the Y toner image by a primary transfer roller 7 as a primary transfer unit.

  By a similar process, a toner image made of cyan (C) toner formed on the C photoconductive drum 1 and a toner image made of black (K) toner formed on the K photoconductive drum 1 are obtained. The toner images are sequentially superimposed on the intermediate transfer member 6, and a superimposed color toner image composed of Y, M, C, and K toners is formed on the peripheral surface of the intermediate transfer member 6.

  The toner remaining on the peripheral surface of each photoreceptor drum 1 after the transfer is cleaned by the photoreceptor cleaning device 190.

  On the other hand, the transfer material P as recording paper accommodated in the paper feed cassettes 20A, 20B, and 20C is fed by the feed roller 21 and the paper feed roller 22A provided in the paper feed cassettes 20A, 20B, and 20C, respectively, and conveyed. A secondary transfer member serving as a secondary transfer unit that is transported on the path 22 by transport rollers 22B, 22C, and 22D and to which a voltage having a polarity opposite to that of the toner (plus polarity in the present embodiment) is applied via the registration roller 23. The superposed color toner image (color image) formed on the intermediate transfer body 6 is transferred onto the transfer material P at a time in the transfer area of the secondary transfer member 7A.

  The transfer material P onto which the color image has been transferred is heated and pressed at the fixing nip NA formed by the heating member 17a and the pressure roller 17b of the fixing device 17, and is fixed by the paper discharge roller 24. It is placed on the outer paper discharge tray 25.

  The above describes the state in which image formation is performed on the first surface, which is one side of the transfer material P. In the case of duplex copying, the sheet discharge switching member 26 is switched, the sheet guide portion 26A is opened, and the transfer is performed. The material P is conveyed in the direction of a broken line arrow.

  Further, the transfer material P is transported to the lower transport path 27B by the transport mechanism 27A, switched back by the sheet reversing portion 27C, and the transport path is switched by the branching portion 27D. And is conveyed into the duplex copying paper feed unit 130.

  The transfer material P moves in the paper feeding direction through a conveyance guide 131 provided in the duplex copying paper supply unit 130, and the transfer material P is re-fed by the paper supply roller 132 and guided to the conveyance path 22.

  Then, as described above, the transfer material P is conveyed in the direction of the secondary transfer member 7A, the toner image is transferred to the second surface which is the back surface of the transfer material P, fixed by the fixing device 17, and then the paper discharge tray. 25 is discharged.

  Further, after the color image is transferred onto the transfer material P by the secondary transfer member 7A as the secondary transfer means, the residual toner on the intermediate transfer body 6 that has separated the curvature of the transfer material P becomes the intermediate transfer body cleaning device 190A. Is removed.

  Further, the patch image toner on the secondary transfer member 7 </ b> A is cleaned by the cleaning blade 71 of the secondary transfer device 70.

  Next, the cleaning means for the member to be cleaned will be described.

  FIG. 2 is a schematic view showing an example of a cleaning unit for the photosensitive member.

In FIG. 2, the photoreceptor 1 has a cleaning blade contact angle represented by θ ₁ . Free length L ₁ of the cleaning blade 16 is the length to the tip A 'of the cleaning blade where it is assumed that not deformed from the end portion B of the blade holder 17 (shown by dotted lines in the drawing). h ₁ indicates the thickness of the cleaning blade. The cleaning blade contact angle θ ₁ represents an angle formed between the tangent line X at the contact point A of the photosensitive member and the cleaning blade assumed not to be deformed. The amount of biting a is a radius r ₀ of the outer periphery S ₀ of the photosensitive member and a radius r ₁₁ of a circle S ₁₁ centered on the same central axis C as the photosensitive member having the tip A ′ of the cleaning blade assumed to be undeformed. It is a difference. Contact angle theta ₁ to the photosensitive member of the cleaning blade is preferably 5 to 35 °. By setting the contact angle within the above range, there is no cleaning failure of the transfer residual toner, and no cleaning blade curling occurs (the cleaning blade tip is moved from the counter direction in the same direction as the rotation direction of the photosensitive member). preferable.

  The free length of the cleaning blade is preferably 6 to 15 mm, and the thickness of the cleaning blade is preferably 0.5 to 10 mm.

  As a material of the cleaning blade, urethane rubber, silicone rubber, fluorine rubber, chloroprene rubber, butadiene rubber, or the like can be used. Among these, urethane rubber is preferable in terms of excellent wear characteristics.

  The shape and material of the cleaning blade can be determined as appropriate according to various conditions such as toner characteristics, photoconductor characteristics, cleaning blade contact angle and contact pressure.

  FIG. 3 is a schematic diagram illustrating an example of a cleaning unit for the intermediate transfer member.

  In FIG. 3, reference numeral 601 denotes a casing, which has a housing portion to which the members constituting the cleaning means 190A are attached and the toner removed from the intermediate transfer body 6 is housed.

  Reference numeral 602 denotes a cleaning blade made of an elastic material such as urethane rubber, and is fixed to the blade holder 603 with an adhesive or the like.

  The blade holder 603 is rotatably attached to a support shaft 604 provided in the casing 601.

  A pressing spring 605 urges the blade holder 603 to rotate counterclockwise around the support shaft 604, and the tip of the cleaning blade 602 is in a direction opposite to the rotation direction of the intermediate transfer body 6 (counter direction). In this state, the intermediate transfer member 6 backed up by the backup roller 75 is disposed in pressure contact with the pressure contact position C.

  Reference numeral 608 denotes a toner guide member formed of a sponge roller. The intermediate transfer member 6 is located upstream of the pressure contact position C between the cleaning blade 602 and the intermediate transfer member 6 in the rotational direction indicated by the arrow of the intermediate transfer member 6. It is arrange | positioned so that it may contact | abut.

  The sponge roller 608 is rotated in the same direction as the intermediate transfer body 6 at a contact position with the intermediate transfer body 6 by a rotating means (not shown), and the peripheral speed of the sponge roller 608 is higher than the peripheral speed of the intermediate transfer body 6. It is configured to be faster.

  Reference numeral 609 denotes a toner discharge regulating member made of a polyester resin (PET) sheet. One end of the toner discharge regulating member abuts on the surface of the sponge roller 608 at a position opposite to the contact position between the sponge roller 608 and the intermediate transfer member 6. The other end is fixed to a sheet holding member 610 provided above the sponge roller 608 with a double-sided tape or the like.

  The sheet holding member 610 is fixed to the protrusion 611 of the casing 601 with a screw or the like.

  With such a configuration, the intermediate transfer body 6, the cleaning blade 602, the sponge roller 608, and the toner discharge regulating member 609 form a space S.

  Reference numeral 612 denotes a collection screw provided at the bottom of the casing 601. The toner stored in the bottom of the casing 601 is transported in a direction perpendicular to the paper surface of the drawing and discharged outside the casing 601.

  As shown in the figure, reference numeral 613 denotes a toner receiving sheet made of PET having one end bonded to the bottom of the casing 601 facing the intermediate transfer body 6 and the other end lightly contacting the intermediate transfer body 6, and the toner inside the casing 601. Prevents falling down.

  In FIG. 3, the cleaning blade is made of urethane rubber, the hardness is 74 ° (JIS, A rubber hardness), and the contact pressure of the tip of the cleaning blade against the intermediate transfer member is set to 16.0. The free length of the cleaning blade is preferably 6 to 15 mm, and the thickness of the cleaning blade is preferably 0.5 to 10 mm.

  FIG. 4 is a schematic diagram illustrating an example of a cleaning unit for the secondary transfer member.

  The shape of the secondary transfer member of the secondary transfer device 70 is not particularly limited, and either a roller shape or a belt shape can be used.

  FIG. 4A shows a cleaning unit using a secondary transfer roller 7A as a secondary transfer member.

  4A shows a state in which the secondary transfer roller 7A is pressure-bonded to the backup roller 6B and the cleaning blade 71 is pressure-bonded to the secondary transfer roller 7A via the intermediate transfer body 6. FIG.

  The secondary transfer device 70 includes the secondary transfer roller 7A and its cleaning means 71, and the position of the rotating shaft 7C of the secondary transfer roller 7A and the cleaning holding portion 73H of the cleaning blade 71 in the cleaning portion 71. The position of the rotation support shaft 73C and the position of the fixing pin 74P that fixes the other end of the spring 74 that is hooked on one end of the cleaning holding portion 73H are fixed to the casing 72 of the secondary transfer device 70. Has been.

  In the above-described embodiment, the spring 74 is formed as an elastic member, and one end thereof is fixed to the cleaning holding portion 73H and the other end is fixed to the housing 72.

  4B shows a cleaning unit in which the secondary transfer roller 7A shown in FIG. 4A is changed to an endless belt 7D.

  4A and 4B, the cleaning blade 71 is made of urethane rubber, has a free length of 9 mm, a thickness of 2 mm, and a spring force of the spring 74 of 18.3 N / m. The contact pressure against the secondary transfer roller is set to 13.7 N / m.

  The transfer sheet P for holding a toner image formed using the toner according to the present invention is usually called an image support, a transfer material or a transfer paper, and is particularly limited as long as it can form a toner image. It is not a thing. Preferred examples include plain paper ranging from thin paper to thick paper, coated printing paper such as art paper and coated paper, commercially available Japanese paper and postcard paper, plastic films for OHP, cloth, and the like.

  Although the embodiment of the present invention will be specifically described, the present invention is not limited to this embodiment.

<Production of toner>
The toner according to the present invention was produced as follows.

<Preparation of toner base particles Bk1>
(1) Preparation of Resin Particle Dispersion 1 Mixing including a monomer composed of 175 parts by mass of styrene, 60 parts by mass of n-butyl acrylate, 15 parts by mass of methacrylic acid, and 7 parts by mass of n-octyl-3-mercaptopropionate The liquid was put into a stainless steel kettle equipped with a stirrer, and 100 parts by mass of pentaerythritol tetrabehenate was added thereto, heated to 70 ° C. and dissolved to prepare a mixed liquid containing monomers.

  On the other hand, a surfactant solution in which 2 parts by mass of sodium polyoxyethylene (2) dodecyl ether sulfate was dissolved in 1350 parts by mass of ion-exchanged water was heated to 70 ° C., and a mixed solution containing the monomer was added and mixed. Then, an emulsified dispersion was prepared by dispersing for 30 minutes with a mechanical disperser CLEARMIX (manufactured by M Technique Co., Ltd.) having a circulation path.

  Next, an initiator solution prepared by dissolving 7.5 parts by mass of potassium persulfate in 150 parts by mass of ion-exchanged water was added to the dispersion, and polymerization was performed by heating and stirring the system at 78 ° C. for 1.5 hours. Resin particles were prepared. A polymerization initiator solution in which 12 parts by mass of potassium persulfate is further dissolved in 220 parts by mass of ion-exchanged water is added to the resin particles, and 320 parts by mass of styrene and 100 parts of n-butyl acrylate are added at a temperature of 80 ° C. The liquid mixture containing the monomer which consists of a mass part, 35 mass parts of methacrylic acid, and 7.5 mass parts of n-octyl-3-mercaptopropionate was dripped over 1 hour.

  After completion of the dropping, the mixture was heated and stirred for 2 hours to proceed the polymerization, and then cooled to 28 ° C. to obtain a resin particle dispersion. This resin particle dispersion is designated as “resin particle dispersion 1”.

(2) Production of Black Colorant Dispersion 1 100 parts by mass of lauryldimethylaminoacetic acid betaine was added to 500 parts by mass of ion-exchanged water and dissolved by stirring. While stirring this liquid, 80 parts by mass of carbon black “Regal 330R” (Cabot Corporation) is gradually added, and then dispersed using a mechanical disperser “CLEARMIX” (M Technique Co., Ltd.). Thus, a colorant dispersion was prepared. This is designated as “colorant dispersion 1”. The particle diameter of the colorant in “Black Colorant Dispersion 1” was 130 nm when measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.).

(3) Preparation of toner base particle Bk1 392 parts by mass of the above-mentioned “resin particle dispersion 1” and 2100 parts by mass of ion-exchanged water are charged into a reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introduction device. The pH was adjusted to 10 by adding a 5 mol / liter sodium hydroxide aqueous solution. Thereafter, 100 parts by mass of “Colorant Dispersion 1” was added, and a 5 mol / liter hydrochloric acid aqueous solution was added to adjust the pH to 3.

  Then, aggregation reaction was performed by heating up. In this state, the particle size of the aggregated particles was measured using “Coulter Multisizer 3” (manufactured by Beckman Coulter), and when the median diameter on the volume basis became 6.6 μm, the temperature was kept at 5 mol / 5% by mass of litter of “10% aqueous solution of compound (1)” with respect to the toner solid content (resin particles + colorant) was added all at once to stop particle growth. Further, the temperature is raised and the mixture is heated and stirred at 90 ° C. to advance particle fusion. Using the above-mentioned FPIA-2100 (the number of detected HPF is 4000), the average circularity is 0.925. Then, the mixture was cooled to 30 ° C. to prepare “Toner Base Particle Dispersion 1”. The produced “toner base particle dispersion 1” is solid-liquid separated with a basket type centrifuge “MARK III type (model number 60 × 40)” (manufactured by Matsumoto Kikai Seisakusho Co., Ltd.) to obtain a wet cake of “toner base particle 1”. Formed.

The formed wet cake was washed with ion-exchanged water at 40 ° C. until the electric conductivity of the filtrate reached 5 μS / cm with the basket-type centrifuge. (Made by Seishin Corporation) and dried until the water content became 0.5 mass% to produce “toner base particle Bk1”. The median diameter (D ₅₀ ) of the obtained “toner base particle Bk1” on a volume basis was 6.5 μm.

<Preparation of toner base particles Bk2 to Bk4>
Example 1 (after correction ) except that “compound (1)” (5% by mass) used in the step of “(3) Preparation of toner base particles” in toner base particle Bk1 was changed to the compounds shown in Table 1 . “Toner base particles Bk2 to Bk4” were prepared in the same manner as the toner base particles Bk1 in Reference Example 1) .

<Preparation of toner base particles Bk5>
The compound (1) used in the step of “(3) Preparation of toner base particles” of the toner base particles Bk1 was “added all at the same temperature at the time of reaching 6.6 μm”. “Toner base particle Bk5” was prepared in the same manner except that the addition was made dropwise over 40 minutes while gradually raising the temperature from the point when the particle size reached 6 μm.

<Preparation of toner base particles Bk6>
“Toner base particle” was similarly changed except that 5% by mass of “10% aqueous solution of compound (1)” used in the step of “(3) Preparation of toner base particle” of toner base particle Bk1 was changed to 10% by mass. Bk6 "was produced.

<Preparation of toner base particles Bk7>
“Toner base particle” was similarly changed except that 5% by mass of “10% aqueous solution of compound (1)” used in the step of “(3) Preparation of toner base particle” of toner base particle Bk1 was changed to 2 parts by mass. Bk7 "was produced.

<Preparation of toner base particles Bk8>
5% by mass of “10% aqueous solution of compound (1)” used in the step of “(3) Preparation of toner base particle” of toner base particle Bk1 is changed to 5% by mass of “10% aqueous solution of compound (A)”. A “toner base particle Bk8” was produced in the same manner as described above.

<Preparation of toner base particles Bk9>
5% by mass of “10% aqueous solution of compound (1)” used in the step of “(3) Preparation of toner base particle” of toner base particle Bk1 is changed to 5% by mass of “10% aqueous solution of compound (B)”. A “toner base particle Bk8” was produced in the same manner as described above.

<Preparation of toner base particles Bk10>
5% by mass of “10% aqueous solution of compound (1)” used in the step of “(3) Preparation of toner base particles” of toner base particle Bk1 is changed to “10% aqueous solution of sodium hydroxide”, and the amount added Added an amount capable of adjusting the pH to pH 5. Otherwise, “toner base particle Bk10” was prepared in the same manner as toner base particle Bk1 of Example 1 (Reference Example 1 after correction) .

Table 1 shows a method for adding the aggregation terminator added at the time of preparation of the toner base particles Bk, the aggregation terminator compound, the amount of addition, and the amount of fine particles contained in the toner base particles.

(Measurement of amount of fine particles mixed in toner base particles)
The amount of fine particles mixed in the toner base particles was measured by dispersing each of the toner base particles Bk prepared above in ion-exchanged water containing a surfactant and using this dispersion using “FPIA”.

  The amount of fine particles mixed is 1% by number or less.

<Preparation of toner base particles C1 to C10>
“Toner base particles C1 to C10” were prepared in the same manner except that the “black colorant dispersion liquid” used in the preparation of the toner base particles Bk1 to Bk10 was changed to the following “cyan colorant dispersion liquid”.

(Preparation of cyan colorant dispersion)
“Cyan” with a median diameter of 153 nm on the basis of the number of pieces was the same except that carbon black “Regal 330R” used in the preparation of the black colorant dispersion was changed to 25 parts by weight of “CI Pigment Blue 15: 3”. A “colorant dispersion” was prepared.

<Preparation of toner base particles M1 to M10>
“Toner base particles M1 to M10” were prepared in the same manner except that the “black colorant dispersion” used in the preparation of the toner base particles Bk1 to Bk10 was changed to the following “magenta colorant dispersion”.

(Preparation of magenta colorant dispersion)
A “magenta colorant dispersion liquid having a median diameter of 183 nm on a number basis is the same as that described above except that the carbon black“ Regal 330R ”used in the preparation of the black colorant dispersion liquid is changed to“ CI Pigment Red 122 ”. Was prepared.

<Preparation of toner base particles Y1 to Y10>
“Toner base particles Y1 to Y10” were prepared in the same manner except that the “black colorant dispersion” used in the preparation of the toner base particles Bk1 to Bk10 was changed to the following “yellow colorant dispersion”.

(Preparation of yellow colorant dispersion)
According to the same procedure except that the carbon black “Regal 330R” used in the preparation of the black colorant dispersion was changed to “CI Pigment Yellow 74”, the “yellow colorant dispersion having a median diameter of 177 nm on a number basis” Was prepared.

  The amount of fine particles contained in “toner base particles C1 to C10”, “toner base particles M1 to M10”, and “toner base particles Y1 to Y10” is the same as “toner base particles Bk1 to Bk10”, and is omitted. .

<Mixing of external additives>
Each of the obtained “toner base particles Bk1 to Bk10”, “toner base particles C1 to C10”, “toner base particles M1 to M10”, and “toner base particles Y1 to Y10” has a number average primary particle diameter of 12 nm. 1% by mass of hydrophobic silica having a hydrophobization degree of 68 and 1% by mass of hydrophobic titanium oxide having a number average primary particle diameter of 20 nm and a hydrophobization degree of 63% were added. Mixing was performed using a “mixer” (Mitsui Miike Chemical Co., Ltd.). Thereafter, coarse particles were removed using a sieve having an opening of 45 μm to prepare “Toners Bk1 to Bk10”, “Toners C1 to C10”, “Toners M1 to M10”, and “Toners Y1 to Y10”.

Each of the produced toners had a median diameter (D ₅₀ ) on the volume basis of 6.5 μm and an average circularity of 0.925.

<< Preparation of developer >>
Next, each of the color toners prepared above and a carrier having an average particle diameter of 35 μm coated with a styrene acrylic resin on the ferrite particles are mixed so that the toner concentration becomes 8% by mass. Agents 1-10 "were prepared.

<< Evaluation using image forming apparatus >>
As an image forming apparatus for evaluation, a commercially available digital printer “bizhub Pro C500 (manufactured by Konica Minolta Business Technologies)” is cleaned with a patch image detection sensor shown in FIG. 1 and a secondary transfer member shown in FIG. A device equipped with a cleaning means was prepared.

Each color toner and each color developer prepared above are sequentially loaded in the image forming apparatus, and a character image with a printing rate of 10% is printed on A4 size high-quality paper in a printing environment of normal temperature and humidity (20 ° C., 50% RH). 400,000 copies were printed on a 64 g / m ² image support.

  The size of the patch image was 1.5 cm × 1.5 cm for all four colors, and the patch image was formed every 1000 sheets printed. The patch image toner was set to be transferred from the intermediate transfer member to the secondary transfer member.

<Cleanability>
The cleaning performance is that after printing of 400,000 sheets, a character image and a patch image with a printing rate of 10% are formed in a printing environment of normal temperature and humidity (20 ° C., 50% RH), cleaned with a cleaning blade, The surfaces of the intermediate transfer member and the secondary transfer member were visually observed to evaluate the cleaning properties of the patch image toner and the transfer residual toner.

Evaluation criteria A: The surface of the photoconductor, intermediate transfer member, and secondary transfer member is good with no defective cleaning. ○: The surface of the photoconductor, intermediate transfer member, and secondary transfer member is slightly defective in cleaning, but is practically used. No problem x: A cleaning defect occurs on any of the surfaces of the photosensitive member, the intermediate transfer member, and the secondary transfer member, and there is a practical problem.

<Cover>
The fog caused by poor cleaning is obtained by passing the high-quality A4 size paper as blank paper after printing 400,000 sheets, and the density of the area corresponding to the character image portion and the patch image portion and the white paper density of the image support. The difference was evaluated.

  The white density of the image support was measured at 20 locations of A4 size, and the average value was defined as the density of the white paper. The density corresponding to the character image portion and the patch image portion was the location corresponding to the character image portion and the patch image portion, respectively. Measure at four locations and use the average value as the fog density. Density measurement was performed using a reflection densitometer “RD-918” (manufactured by Macbeth). In addition, evaluation of fogging | cover is a pass density | concentration of 0.03 or less with no problem in practical use.

  Table 2 shows the results of evaluation using the image forming apparatus.

From the evaluation results of Table 2, it can be seen that “ Reference Examples 1 to 5 and Examples 3 and 4 ” of the present invention are satisfactory for all evaluation items. On the other hand, it can be seen that “Comparative Examples 1 to 3” outside the present invention has a problem in any of the evaluation items, and the object of the present invention has not been achieved.

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Charging device as charging means 3 Exposure optical system as image writing means 4 Developing device as developing means 6 Intermediate transfer member 7A Secondary transfer member 70 Secondary transfer device 100 Process unit 190A Cleaning device

Claims (4)

In a method for producing a toner for developing an electrostatic charge image having a step of producing toner base particles by aggregating and fusing at least resin particles and a colorant,
After aggregating the resin particles and the colorant in the step of preparing the toner base particles,
Method for producing a toner for developing electrostatic images, which comprises adding a compound represented by the following general formula (2).

In the formula, the heterocyclic structure represented by a dotted line represents a cyclic structure R ₄ having a C ₄ or C ₅ nitrogen atom, and H, a C _{1 to} C ₃ alkyl group or an alkanol group. Formula (2) is a compound represented by, after by aggregating the resin particles colorant, manufacturing method of the electrostatic image developing toner according to claim 1, characterized in that they are added together.   An electrostatic image developing toner produced by the method for producing an electrostatic image developing toner according to claim 1.   The toner for developing an electrostatic charge image according to claim 3 is loaded, and a toner image formed with the toner for developing an electrostatic charge image is transferred to a transfer material, and then, a transfer residual toner that is not transferred is cleaned with a cleaning blade. An image forming method.

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