JP2011095341A - Toner, developing agent and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner which is excellent in low temperature fixing property, heat-resistant storage and development stability, and can prevent occurrence of winding of a recording medium even when increasing the surface pressure of fixing during the fixing at a low temperature, to provide a developing agent containing the toner, and to provide an image forming method using the developing agent. <P>SOLUTION: The toner comprises a mother toner particle, the mother toner particle has a core-shell structure composed of a core comprising a binder resin and a releasing agent, and a shell having a thickness of 0.01 to 2 μm, the core has a softening index of 60 to 85 °C, and the shell has a thermal hardness of 0.7 to 1.8. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a toner, a developer, and an image forming method.

  In an image forming apparatus such as an electrophotographic apparatus or an electrostatic recording apparatus, a toner image formed by developing an electrostatic latent image formed on a photoreceptor using toner is applied to a recording medium such as paper. After the transfer, the image is formed by fixing by heating. In forming a full-color image, development is generally performed using toners of four colors, black, yellow, magenta, and cyan. The toner images of the respective colors are transferred onto a recording medium and superimposed, and then heated. Fix at the same time.

  At this time, if the softening property of the toner is lowered to improve the low-temperature fixability, the heat-resistant storage stability of the toner is lowered. Further, the development stability is lowered due to the spent toner on the developing member and the carrier.

  Therefore, Patent Document 1 discloses a core-shell type toner containing a release agent, a colorant, a binder resin and a filler as an electrostatic charge image developing toner. At this time, the flow tester 1/2 outflow temperature of the toner is 60 ° C. or higher and 100 ° C. or lower, and the shell contains the thermoplastic resin.

  However, when fixing at a low temperature, there is a problem that even if the fixing surface pressure is increased, the release agent contained in the core does not sufficiently bleed out and winding occurs.

  The present invention is excellent in low temperature fixability, heat resistant storage stability and development stability in view of the problems of the above-described conventional technology, and suppresses the occurrence of winding even when fixing surface pressure is increased when fixing at low temperature. It is an object of the present invention to provide a toner that can be used, a developer containing the toner, and an image forming method using the developer.

  The invention according to claim 1 is a toner having base particles, wherein the base particles include a core including a binder resin and a release agent, and a core shell having a thickness of 0.01 μm to 2 μm. The core has a softening index of 60 ° C. or more and 85 ° C. or less, and the shell has a thermal hardness of 0.7 or more and 1.8 or less.

  According to a second aspect of the present invention, in the toner according to the first aspect, the shell includes resin particles.

  According to a third aspect of the present invention, in the toner according to the first or second aspect, the binder resin includes a polyester and / or a urea-modified polyester.

  According to a fourth aspect of the present invention, in the toner according to the third aspect, the base particles include a solution obtained by dissolving or dispersing a toner material containing a polyester prepolymer having an isocyanate group in an organic solvent in an aqueous medium. It is formed by emulsifying or dispersing and then adding the polyester prepolymer and a compound having an amino group.

  According to a fifth aspect of the present invention, in the toner according to the fourth aspect, the aqueous medium includes resin particles.

  According to a sixth aspect of the present invention, in the toner according to the fourth or fifth aspect, the toner material further includes polyester.

  According to a seventh aspect of the present invention, in the toner according to any one of the first to sixth aspects, the average circularity is 0.93 or more and 0.99 or less.

  According to an eighth aspect of the present invention, in the toner according to any one of the first to seventh aspects, the shape factor SF-1 is 100 or more and 150 or less, and the shape factor SF-2 is 100 or more and 140 or less. It is characterized by that.

  According to a ninth aspect of the invention, in the toner according to any one of the first to eighth aspects, the weight average particle size is 2 μm or more and 7 μm or less, and the ratio of the weight average particle size to the number average particle size is 1. 0.000 or more and 1.25 or less.

  According to a tenth aspect of the present invention, the developer includes the toner according to any one of the first to ninth aspects.

  According to an eleventh aspect of the present invention, in the image forming method, the step of forming an electrostatic latent image on the electrostatic latent image carrier, and the development of the electrostatic latent image using the developer according to the tenth aspect. Forming a toner image, transferring the toner image to a recording medium, and fixing the toner image transferred to the recording medium.

A twelfth aspect of the present invention is the image forming method according to the eleventh aspect, wherein the toner is formed by pressurizing the recording medium onto which the toner image is transferred with a surface pressure of 10 N / cm ² or more and 150 N / cm ² or less. The image is fixed, and the system speed is 500 mm / second or more and 2.5 × 10 ³ mm / second or less.

  According to the present invention, a toner that has excellent low-temperature fixability, heat-resistant storage stability, and development stability, and can suppress the occurrence of winding even when the fixing surface pressure is increased when fixing at low temperature, and the toner And an image forming method using the developer.

It is a figure explaining the measuring method of the softening index | exponent of a core, and the thermal hardness of a shell. It is a figure which shows an example of the image forming apparatus used by this invention. FIG. 3 is a diagram illustrating an image forming unit in FIG. 2.

  Next, the form for implementing this invention is demonstrated with drawing.

  The toner of the present invention has base particles, and the base particles have a core-shell structure including a core containing a binder resin and a release agent, and a shell.

  The softening index Ct of the core is 60 to 85 ° C, preferably 63 to 77 ° C. When Ct is less than 60 ° C., the heat-resistant storage stability decreases, and when it exceeds 85 ° C., the low-temperature fixability decreases.

  Ct is a toner outflow start temperature when a flow tester CFT-500D (manufactured by Shimadzu Corporation) is used and the load is 25 kg. That is, Ct is considered to be the toner outflow start temperature at which the shell structure is broken because the load is large.

  The thermal hardness St of the shell is 0.7 to 1.8, and preferably 1.0 to 1.8. When St is less than 0.7, the heat resistant storage stability and development stability are lowered, and when it exceeds 1.8, the low-temperature fixability is lowered, and even when the fixing surface pressure is increased, winding occurs.

  In addition, St uses a flow tester CFT-500D (manufactured by Shimadzu Corporation) to measure the toner outflow start temperature when the load is 2 kg to 25 kg, and plots the load on the horizontal axis and the outflow start temperature on the vertical axis. It is the product of -1 and -1

  When St is small, the outflow start temperature does not increase even if the load is reduced. That is, even if the load is small, the structure of the shell is destroyed, so that the toner is easily softened. On the other hand, when St is large, decreasing the load increases the toner outflow start temperature. That is, when the load is small, the structure of the shell is difficult to be destroyed, so that the toner is difficult to soften.

The flow tester CFT-500D (manufactured by Shimadzu Corporation), as shown in FIG. 1 (a), preheats the tableted toner T placed in the cylinder C, and then applies a constant load by the plunger P. By raising the temperature of the heating element H, the melted toner T ′ is caused to flow out of the die D, and the amount of lowering of the plunger P with respect to the temperature of the heating element H is measured as shown in FIG. The flow tester CFT-500D (manufactured by Shimadzu Corporation) is generally used when measuring the outflow start temperature T _fb or T _1/2 temperature with a constant load, but in the present invention, the load is changed. It was found that St can be evaluated by measuring the outflow start temperature T _fb of. St indicates the pressure dependency of the outflow start temperature T _fb of the toner.

  The thickness of the shell is 0.01 to 2 μm, preferably 0.4 to 1.5 μm. When the thickness of the shell is less than 0.01 μm, the heat resistant storage stability and the development stability are lowered, and when it exceeds 2 μm, the low-temperature fixability is lowered, and even when the fixing surface pressure is increased, the winding occurs.

  The thickness of the shell can be measured using a TEM (transmission electron microscope), FE-SEM (scanning electron microscope), SPM (scanning probe microscope), etc. The average thickness of the toner shell.

  In the present invention, the shell preferably contains resin particles. Thereby, a uniform core-shell structure and a core-shell structure having different softening temperatures between the core and the shell can be stably formed.

  The glass transition point of the resin particles is preferably 40 to 100 ° C. When the glass transition point is less than 40 ° C., the heat-resistant storage stability of the toner may be lowered, and when it exceeds 100 ° C., the low-temperature fixability may be lowered.

The weight average molecular weight of the resin particles is more preferably 3 × 10 ^{3 to} 3 × 10 ⁵ . When the weight average molecular weight is less than 3 × 10 ³ , the heat-resistant storage stability of the toner may be lowered, and when it exceeds 2 × 10 ⁵ , the low-temperature fixability may be lowered.

  The resin particle content in the toner is preferably 0.5 to 5.0 mass%. When the content of the resin particles is less than 0.5% by mass, the heat resistant storage stability and the development stability are lowered, and when it exceeds 5.0% by mass, the low-temperature fixability is lowered and the fixing surface pressure is increased. Also, winding will occur.

  The content of the resin particles in the toner is determined from the peak area by analyzing a substance caused by the resin particles and not by the material constituting the toner other than the resin particles using a pyrolysis gas chromatograph mass spectrometer. Can be calculated.

  The resin constituting the resin particles is not particularly limited, and may be any of a thermoplastic resin and a thermosetting resin. Vinyl resin, polyurethane, epoxy resin, polyester, polyamide, polyimide, silicon resin, phenol Resins, melamine resins, urea resins, aniline resins, ionomer resins, polycarbonates and the like may be mentioned, and two or more of them may be used in combination. Among these, vinyl resins, polyurethanes, epoxy resins, and polyesters are preferable because they easily form an aqueous dispersion of fine spherical resin particles.

  The vinyl resin is not particularly limited, but a styrene- (meth) acrylic acid ester copolymer, a styrene-butadiene copolymer, a (meth) acrylic acid-acrylic acid ester copolymer, a styrene-acrylonitrile copolymer, Styrene-maleic anhydride copolymer, styrene- (meth) acrylic acid copolymer and the like can be mentioned, and styrene-butyl methacrylate copolymer is particularly preferable.

  In the present invention, the binder resin preferably contains polyester and / or urea-modified polyester. At this time, by using the polyester and the urea-modified polyester in combination, the low-temperature fixability and the glossiness and gloss uniformity of the full-color image can be improved. Further, the binder resin may contain a modified polyester other than urea-modified polyester such as urethane-modified polyester.

  Polyester heats polyol (1) and polycarboxylic acid (2) to 150-280 ° C in the presence of a catalyst such as tetrabutoxytitanate, dibutyltin oxide, etc. And obtained by polycondensation.

  Examples of the polyol (1) include a diol (1-1) and a trivalent or higher polyol (1-2). The diol (1-1) or the diol (1-1) and a trivalent or higher polyol (1) -2) is preferred.

  Diol (1-1) is not particularly limited, but alkylene glycol such as ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol; diethylene glycol Alkylene ether glycols such as triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol; alicyclic diols such as 1,4-cyclohexanedimethanol and hydrogenated bisphenol A; bisphenol A, bisphenol F Bisphenols such as bisphenol S; alkylene oxides such as alicyclic diols or bisphenols such as ethylene oxide, propylene oxide, butylene oxide Addendum and the like, may be used in combination. Among them, alkylene glycols having 2 to 12 carbon atoms and alkylene oxide adducts of bisphenols are preferable, and the combination of alkylene oxide adducts of bisphenols and alkylene oxide adducts of bisphenols with alkylene glycols having 2 to 12 carbon atoms is preferable. Particularly preferred.

  Examples of the trivalent or higher polyol (1-2) include glycerin, trimethylol ethane, trimethylol propane, pentaerythritol, sorbitol and the like trihydric or higher polyhydric aliphatic alcohols; trisphenol PA, phenol novolac, Trivalent or higher phenols such as cresol novolak; alkylene oxide adducts such as ethylene oxide, propylene oxide, butylene oxide of trivalent or higher phenols, and the like may be used in combination.

  Examples of the polycarboxylic acid (2) include dicarboxylic acid (2-1) and tri- or higher valent polycarboxylic acid (2-2), and dicarboxylic acid (2-1) or dicarboxylic acid (2-1) Use of a trivalent or higher polycarboxylic acid (2-2) is preferred.

  Although it does not specifically limit as dicarboxylic acid (2-1), Alkylene dicarboxylic acid, such as succinic acid, adipic acid, and sebacic acid; Alkenylene dicarboxylic acid, such as maleic acid and fumaric acid; Phthalic acid, isophthalic acid, terephthalic acid, naphthalene Aromatic dicarboxylic acids such as dicarboxylic acids may be mentioned, and two or more of them may be used in combination. Among these, alkenylene dicarboxylic acids having 4 to 20 carbon atoms and aromatic dicarboxylic acids having 8 to 20 carbon atoms are preferable.

  Examples of the trivalent or higher polycarboxylic acid (2-2) include aromatic polycarboxylic acids having 9 to 20 carbon atoms such as trimellitic acid and pyromellitic acid, and two or more kinds may be used in combination.

  In place of the polycarboxylic acid (2), an anhydride of the polycarboxylic acid (2) or a lower alkyl ester such as methyl ester, ethyl ester or isopropyl ester may be used.

The peak molecular weight of polyester is usually 1 × 10 ^{3 to} 3 × 10 ⁴ , preferably 1.5 × 10 ³ to 1 × 10 ^{4, and} more preferably 2 × 10 ³ to 8 × 10 ³ . When the peak molecular weight is less than 1 × 10 ³ , the heat-resistant storage stability may be lowered, and when it exceeds 3 × 10 ⁴ , the low-temperature fixability may be lowered.

  In the present invention, the peak molecular weight is a molecular weight in terms of polystyrene measured using GPC (gel permeation chromatography).

  The hydroxyl value of the polyester is usually 5 KOH mg / g or more, preferably 10 to 120 KOH mg / g, and more preferably 20 to 80 KOH mg / g. If the hydroxyl value is less than 5 KOHmg / g, it may be difficult to achieve both heat-resistant storage stability and low-temperature fixability.

  In this invention, a hydroxyl value can be measured based on the measuring method as described in JISK1557-1.

  The acid value of the polyester is usually 0.5 to 40 KOH mg / g, preferably 5 to 35 KOH mg / g. If the acid value is less than 0.5 KOHmg / g, it may be difficult to make it negatively charged. If it exceeds 40 KOHmg / g, it may be affected by the environment under high temperature and high humidity and low temperature and low humidity. It is easy and the image may be deteriorated.

  In the present invention, the acid value can be measured according to the measurement method described in JIS K0070-1992.

  In the present invention, the urea-modified polyester is obtained by adding a polyester prepolymer (A) having an isocyanate group and a compound (B) having an amino group.

  The polyester prepolymer (A) having an isocyanate group can be obtained by adding a polyester having an active hydrogen group and a polyisocyanate (3) at 40 to 140 ° C. Examples of the active hydrogen group include a hydroxyl group (alcoholic hydroxyl group and phenolic hydroxyl group), an amino group, a carboxyl group, a mercapto group, etc. Among them, an alcoholic hydroxyl group is preferable.

  A polyester having an alcoholic hydroxyl group as an active hydrogen group can be obtained by polycondensation of the aforementioned polyol (1) and polycarboxylic acid (2). At this time, the equivalent ratio of the alcoholic hydroxyl group to the carboxyl group is usually 1 to 2, preferably 1 to 1.5, and more preferably 1.02 to 1.3.

  Although it does not specifically limit as polyisocyanate (3), Aliphatic polyisocyanates, such as tetramethylene diisocyanate, hexamethylene diisocyanate, 2, 6- diisocyanatomethyl caproate; Cycloaliphatic polyisocyanates, such as isophorone diisocyanate and cyclohexylmethane diisocyanate Isocyanates; aromatic diisocyanates such as tolylene diisocyanate and diphenylmethane diisocyanate; aromatic aliphatic diisocyanates such as α, α, α ′, α′-tetramethylxylylene diisocyanate; isocyanurates and the like. Also good.

  Instead of polyisocyanate (3), polyisocyanate (3) blocked with a phenol derivative, oxime, caprolactam or the like may be used.

  The equivalent ratio of the isocyanate group to the alcoholic hydroxyl group when the polyester having an active hydrogen group and the polyisocyanate (3) are added is usually 1 to 5, preferably 1.2 to 4, and preferably 1.5 to 2. 5 is more preferable. When the equivalent ratio is less than 1, the urea bond content in the urea-modified polyester is reduced, and the hot offset resistance of the toner may be insufficient. May be insufficient.

  Content of the structural component derived from the polyisocyanate (3) in the polyester prepolymer (A) having an isocyanate group is usually 0.5 to 40% by mass, preferably 1 to 30% by mass, and 2 to 20% by mass. % Is more preferable. When the content is less than 0.5% by mass, the hot offset resistance of the toner may be insufficient, and when it exceeds 40% by mass, the low-temperature fixability may be insufficient.

  The average value of the isocyanate group content per molecule of the polyester prepolymer (A) having an isocyanate group is usually 1 or more, preferably 1.5 to 3, and 1.8 to 2.5. Is more preferable. If the average value of the contents is less than 1, the molecular weight of the urea-modified polyester becomes small, and the hot offset resistance may be insufficient.

  The compound (B) having an amino group is not particularly limited, and examples thereof include a diamine (B1), a trivalent or higher polyamine (B2), an amino alcohol (B3), an amino mercaptan (B4), and an amino acid (B5). However, the combined use of diamine (B1) or diamine (B1) and trivalent or higher polyamine (B2) is preferred.

  Examples of the diamine (B1) include aromatic diamines such as phenylenediamine, diethyltoluenediamine, and 4,4′diaminodiphenylmethane; fats such as 4,4′-diamino-3,3′-dimethyldicyclohexylmethane, diaminecyclohexane, and isophoronediamine. Cyclic diamines; aliphatic diamines such as ethylenediamine, tetramethylenediamine, hexamethylenediamine and the like may be used, and two or more of them may be used in combination.

  Examples of the trivalent or higher polyamine (B2) include diethylenetriamine and triethylenetetramine, and two or more kinds may be used in combination.

  Examples of the amino alcohol (B3) include ethanolamine and hydroxyethylaniline, and two or more kinds may be used in combination.

  Examples of amino mercaptan (B4) include aminoethyl mercaptan and aminopropyl mercaptan, and two or more of them may be used in combination.

  Examples of the amino acid (B5) include aminopropionic acid and aminocaproic acid, and two or more kinds may be used in combination.

  In addition, you may use what blocked the amino group of the compound (B) which has an amino group instead of the compound (B) which has an amino group. The amino group-blocked amino group of the compound (B) having an amino group is not particularly limited, but is a ketimine compound obtained from a compound (B) having an amino group and a ketone such as acetone, methyl ethyl ketone, methyl isobutyl ketone, or oxazoline. Compounds and the like.

  When adding the polyester prepolymer (A) having an isocyanate group and the compound (B) having an amino group, a catalyst such as dibutyltin laurate or dioctyltin laurate may be used as necessary. At this time, reaction time is 10 minutes-40 hours normally, and 2-24 hours are preferable. Moreover, reaction temperature is 0-150 degreeC normally, and 40-98 degreeC is preferable.

  In addition, the equivalent ratio of the isocyanate group with respect to the amino group at the time of adding the polyester prepolymer (A) which has an isocyanate group, and the compound (B) which has an amino group is 0.5-2 normally, and 2/3 1.5 is preferable, and 5/6 to 1.2 is more preferable. When this equivalent ratio is less than 0.5 or exceeds 2, the molecular weight of the urea-modified polyester may become small, and the hot offset resistance may be insufficient.

  If necessary, the molecular weight of the urea-modified polyester can be adjusted using a stopper. As the terminator, monoamines such as diethylamine, dibutylamine, butylamine, and laurylamine and those in which the amino group of the monoamine is blocked can be used. (Ketimine compound). The amino group blocked in the monoamine is not particularly limited, and examples thereof include ketimine compounds and oxazoline compounds obtained from monoamines and ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone.

  It is preferable that at least a part of the urea-modified polyester and the polyester are compatible. That is, the polyester component in the urea-modified polyester is preferably similar to the polyester composition. Thereby, the low-temperature fixability and hot offset resistance of the toner can be improved.

  The mass ratio of the urea-modified polyester to the polyester is usually 5/95 to 75/25, preferably 10/90 to 25/75, more preferably 12/88 to 25/75, and 12/88 to 22/78. Is particularly preferred. When this mass ratio is less than 5/95, the hot offset resistance may be insufficient, and when it exceeds 75/25, the low-temperature fixability may be insufficient.

  The release agent is not particularly limited, but includes polyolefin waxes such as polyethylene wax and polypropylene wax; long-chain hydrocarbons such as paraffin wax and sazol wax; waxes having a carbonyl group; Also good. Among these, a wax having a carbonyl group is preferable.

  Examples of the wax having a carbonyl group include carnauba wax, montan wax, trimethylolpropane tribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, and 1,18-octadecanediol diester. Polyalkanoic acid esters such as stearate; Polyalkanol esters such as tristearyl trimellitic acid and distearyl maleate; Polyalkanoic acid amides such as ethylenediamine dibehenyl amide; Polyalkylamides such as trimellitic acid tristearyl amide; Distearyl Examples thereof include dialkyl ketones such as ketones, among which polyalkanoic acid esters are preferable.

  The melting point of the release agent is usually 40 to 160 ° C, preferably 50 to 120 ° C, and more preferably 60 to 90 ° C. If the melting point is less than 40 ° C., the heat resistant storage stability of the toner may be insufficient, and if it exceeds 160 ° C., cold offset may occur when fixing at a low temperature.

  The melt viscosity at a temperature 20 ° C. higher than the melting point of the release agent is preferably 5 to 1000 cps, more preferably 10 to 100 cps. When the melt viscosity is less than 5 cps, the dispersibility of the release agent in the base particles may be insufficient, and when it exceeds 1000 cps, the hot offset resistance and low-temperature fixability of the toner may be insufficient. is there.

  The content of the release agent in the toner is usually 0 to 40% by mass, and preferably 3 to 30% by mass.

  In the present invention, the core may further contain a colorant, a charge control agent and the like.

  Although it does not specifically limit as a coloring agent (dye or pigment), carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, ocher, yellow lead, Titanium Yellow, Polyazo Yellow, Oil Yellow, Hansa Yellow (GR, A, RN, R), Pigment Yellow L, Benzidine Yellow (G, GR), Permanent Yellow (NCG), Vulcan Fast Yellow (5G, R), Tart Rajn Lake, Quinoline Yellow Lake, Anthrazan Yellow BGL, Isoindolinone Yellow, Bengala, Red Dan, Red Zhu, Cadmium Red, Cadmium Mercury Red, Antimon Zhu, Permanent Red 4R, Para Red, Faise Red, Parachloro Ortho Nitroaniline Les , Resol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carnmin BS, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Resol Rubin GX, Permanent Red F5R, Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Tolujing Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thio Indigo Red B, Thioindigo Maroon, Oil Red, Quinacridone Red, Pyrazolone Red, Polyazole Chrome vermilion, benzidine orange, perinone orange, oil orange, cobalt blue, cerulean blue, alkali blue rake, peacock blue rake, Victoria blue rake, metal-free phthalocyanine blue, phthalocyanine blue, fast sky blue, indanthrene blue (RS, BC), indigo, ultramarine blue, bitumen, anthraquinone blue, fast violet B, methyl violet lake, cobalt purple, manganese purple, dioxane violet, anthraquinone violet, chrome green, zinc green, chromium oxide, pyridian, emerald green, pigment Green B, Naphthol Green B, Green Gold, Acid Green Lake, Malachite Green Lake, Phthalocyanine And anthraquinone green, titanium oxide, zinc white, lithobon and the like.

  The content of the colorant in the toner is usually 1 to 15% by mass, and preferably 3 to 10% by mass.

  The pigment may be combined with a resin and used as a master batch. Such a resin is not particularly limited, but the above-mentioned polyester and urea-modified polyester; polymers of styrene such as polystyrene, poly p-chlorostyrene, polyvinyltoluene and the like; and styrene-p-chlorostyrene copolymers. Styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer Styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene -Acrylonitrile copolymer, Len-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer, etc. Styrene copolymer; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, polyacrylic acid, rosin, modified rosin Terpene resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax and the like, and two or more kinds may be used in combination.

  The master batch is obtained by applying a high shearing force to the pigment and the resin and mixing and kneading. At this time, an organic solvent can be used in order to improve the interaction between the pigment and the resin.

  The master batch is obtained by mixing and kneading an aqueous pigment paste together with a resin and an organic solvent, transferring the pigment to the resin side, and then removing the moisture and the organic solvent (flushing method). At this time, since the wet cake of the pigment can be used as it is, it is not necessary to dry it when preparing the pigment.

  When mixing and kneading, a high shear dispersion device such as a three-roll mill can be used.

  The charge control agent is not particularly limited, but nigrosine dye, triphenylmethane dye, chromium-containing metal complex dye, molybdate chelate pigment, rhodamine dye, alkoxy amine, quaternary ammonium salt (fluorine-modified quaternary ammonium salt) Salt), alkylamide, phosphorus simple substance or compound, tungsten simple substance or compound, fluorine-based surfactant, salicylic acid metal salt, salicylic acid derivative metal salt, copper phthalocyanine, perylene, quinacridone, azo pigment, etc. Two or more kinds may be used in combination. Examples of the charge control agent other than these include polymer compounds having a functional group such as a sulfonic acid group, a carboxyl group, and a quaternary ammonium base.

  Commercially available charge control agents include Nigrosine dye Bontron 03, quaternary ammonium salt Bontron P-51, metal-containing azo dye Bontron S-34, oxynaphthoic acid metal complex E-82, salicylic acid metal Complex E-84, phenolic condensate E-89 (above, Orient Chemical Industries); quaternary ammonium salt molybdenum complex TP-302, TP-415 (above, Hodogaya Chemical Co., Ltd.), 4 Quaternary ammonium salt copy charge PSY VP2038, triphenylmethane derivative copy blue PR, quaternary ammonium salt copy charge NEG VP2036, copy charge NX VP434 (from Hoechst), LRA-901, boron complex LR- 147 (made by Nippon Carlit Co., Ltd.).

  The content of the charge control agent in the toner is preferably 0 to 10% by mass, and more preferably 0.2 to 5% by mass with respect to the binder resin. When the content exceeds 10% by mass, the chargeability of the toner is too high, the electrostatic attraction with the developing roller is increased, and the fluidity of the toner may be decreased or the image density may be decreased. .

  In the present invention, the base particles are obtained by emulsifying or dispersing a solution obtained by dissolving or dispersing a toner material containing an isocyanate group-containing polyester prepolymer (A) and a release agent in an organic solvent, It can be formed by adding a polyester prepolymer (A) having a group and a compound (B) having an amino group. At this time, the toner material may further include polyester, a colorant, a charge control agent, and the like.

  The aqueous medium is not particularly limited, and examples thereof include water, a solvent miscible with water and a mixed solvent of water. Solvents miscible with water are not particularly limited, but include alcohols such as methanol, isopropanol and ethylene glycol, cellsolves such as dimethylformamide, tetrahydrofuran and methylcellosolve, lower ketones such as acetone and methylethylketone, and the like. Two or more kinds may be used in combination.

  In the present invention, the aqueous medium preferably contains resin particles. Thereby, the base particle which has the core shell structure which consists of a core containing urea modified polyester and a mold release agent, and a shell containing resin particles is obtained.

When emulsifying or dispersing a liquid obtained by dissolving or dispersing a toner material in an organic solvent in an aqueous medium, a low-speed shear disperser, a high-speed shear disperser, a friction disperser, a high-pressure jet disperser, A disperser such as a sonic disperser can be used, but a high-speed shear disperser is preferable. When using a high-speed shearing disperser, the number of rotations is usually 1 × 10 ^{3 to} 3 × 10 ⁴ rpm, preferably 5 × 10 ³ to 2 × 10 ⁴ rpm. The dispersion time is usually 0.1 to 5 minutes in the case of a batch method. Moreover, the temperature at the time of dispersion | distribution is 0-150 degreeC (under pressure) normally, and 40-98 degreeC is preferable. At this time, when the temperature at the time of dispersion is higher, the viscosity of the liquid obtained by emulsifying or dispersing the liquid obtained by dissolving or dispersing the toner material in the organic solvent in the aqueous medium decreases, and the dispersion becomes easier. .

  The toner material other than the polyester prepolymer (A) having an isocyanate group and the release agent is added when a liquid obtained by dissolving or dispersing the toner material in an organic solvent is emulsified or dispersed in an aqueous medium, You may mix. In addition, the polyester prepolymer (A) having an isocyanate group, the compound (B) having an amino group, and a toner material other than the release agent include a polyester prepolymer (A) having an isocyanate group and a compound (B) having an amino group. You may add after adding. For example, a colorant may be added by a known dyeing method using a toner material that does not contain a colorant.

  The mass ratio of the aqueous medium to the toner material is usually from 0.5 to 20, and preferably from 1 to 10. If the mass ratio is less than 0.5, the dispersion state of the toner material may be deteriorated, and base particles having a predetermined particle size may not be obtained. If the mass ratio is more than 20, it is not economical.

  The aqueous medium may contain a dispersant. Accordingly, the dispersion stability of a liquid obtained by emulsifying or dispersing a liquid obtained by dissolving or dispersing a toner material in an organic solvent in an aqueous medium can be improved, and the particle size distribution of the toner can be narrowed. As the dispersant, a surfactant, an inorganic dispersant, or the like can be used.

  The surfactant is not particularly limited, but anionic surfactants such as alkylbenzene sulfonates, α-olefin sulfonates and phosphate esters; alkylamine salts, aminoalcohol fatty acid derivatives, polyamine fatty acid derivatives, imidazolines and the like. Cationic surfactants such as amine salt type, alkyltrimethylammonium salt, dialkyldimethylammonium salt, alkyldimethylbenzylammonium salt, pyridinium salt, alkylisoquinolinium salt, quaternary ammonium salt type such as benzethonium chloride; fatty acid amide Nonionic surfactants such as derivatives and polyhydric alcohol derivatives; amphoteric boundaries such as alanine, dodecylbis (aminoethyl) glycine, bis (octylaminoethyl) glycine, N-alkyl-N, N-dimethylammonium betaine Active agents. Among these, a surfactant having a fluoroalkyl group is preferable because the addition amount can be very small.

  Examples of the anionic surfactant having a fluoroalkyl group include a fluoroalkylcarboxylic acid having 2 to 10 carbon atoms and a metal salt thereof, disodium perfluorooctanesulfonylglutamate, 3- [ω-fluoroalkyl (C6 to C11) oxy. ] Sodium 1-alkyl (C3-C4) sulfonate, sodium 3- [ω-fluoroalkanoyl (C6-C8) -N-ethylamino] -1-propanesulfonate, fluoroalkyl (C11-C20) carboxylic acid and Metal salts, perfluoroalkyl carboxylic acids (C7 to C13) and their metal salts, perfluoroalkyl (C4 to C12) sulfonic acids and their metal salts, perfluorooctane sulfonic acid diethanolamide, N-propyl-N- (2- Hydroxyethyl) perfluorooctane Examples include honamide, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (C6-C10) -N-ethylsulfonylglycine salt, monoperfluoroalkyl (C6-C16) ethyl phosphate, and the like.

  Commercially available anionic surfactants having a fluoroalkyl group include Surflon S-111, S-112, S-113 (Asahi Glass Co., Ltd.), Florard FC-93, FC-95, FC-98, FC-129. (Manufactured by Sumitomo 3M), Unidyne DS-101, DS-102 (manufactured by Daikin Industries, Ltd.), MegaFuck F-110, F-120, F-113, F-191, F-812, F-833 (Dainippon) Ink Co., Ltd.), Ectop EF-102, 103, 104, 105, 112, 123A, 123B, 306A, 501, 201, 204 (manufactured by Tochem Products), Footent F-100, F-150 (Neos) Etc.).

  The anionic surfactant having a fluoroalkyl group is not particularly limited, but an aliphatic primary, secondary or tertiary amino acid having a fluoroalkyl group, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt. Aliphatic quaternary ammonium salts such as benzalkonium salt, benzethonium chloride, pyridinium salt, imidazolinium salt and the like.

  Commercially available anionic surfactants having a fluoroalkyl group include Surflon S-121 (Asahi Glass Co., Ltd.), Florard FC-135 (Sumitomo 3M Co., Ltd.), Unidyne DS-202 (Daikin Kogyo Co., Ltd.), Mega Fuck F-150, F-824 (Dainippon Ink Co., Ltd.), Xtop EF-132 (Tochem Products Co., Ltd.), Footent F-300 (Neos Co., Ltd.) and the like can be mentioned.

  The inorganic dispersant is not particularly limited, and examples thereof include tricalcium phosphate, calcium carbonate, titanium oxide, colloidal silica, and hydroxyapatite.

  In the case of using a dispersant, the base particles can be used with the dispersant remaining on the surface. However, considering the chargeability of the toner, it is preferable to remove the dispersant by washing. For example, when an acid such as calcium phosphate or an alkali-soluble compound is used as the dispersant, the calcium phosphate can be removed from the base particles by dissolving the calcium phosphate with an acid such as hydrochloric acid and then washing with water. . In addition, calcium phosphate can be removed from the base particles by decomposing with an enzyme.

  The aqueous medium may contain a polymeric protective colloid. The polymer protective colloid is not particularly limited, but acids such as acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid and maleic anhydride; Β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, β-hydroxypropyl acrylate, β-hydroxypropyl methacrylate, γ-hydroxypropyl acrylate, γ-hydroxypropyl methacrylate, 3-chloro-2 acrylate -Hydroxypropyl, 3-chloro-2-hydroxypropyl methacrylate, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerol monoacrylate, glycerol monomethacrylate, N-methylol acrylic (Meth) acrylic monomers containing hydroxyl groups such as luamide and N-methylolmethacrylamide; vinyl alcohols; ethers with vinyl alcohols such as vinyl methyl ether, vinyl ethyl ether and vinyl propyl ether; vinyl acetate and propionic acid Esters of vinyl alcohol and carboxylic acid such as vinyl and vinyl butyrate; Acrylamide, methacrylamide, diacetone acrylamide, and methylolates thereof; Acid chlorides such as acrylic acid chloride and methacrylic acid chloride; Vinyl pyridine, vinyl pyrrolidone, vinyl imidazole And homopolymers or copolymers such as those having a nitrogen atom such as ethyleneimine or a heterocyclic ring thereof. Other polymeric protective colloids include polyoxyethylene, polyoxypropylene, polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonylphenyl. Examples include polyoxyethylenes such as ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, polyoxyethylene nonyl phenyl ester; and celluloses such as methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose.

  In the present invention, a liquid obtained by dissolving or dispersing a toner material in an organic solvent is emulsified or dispersed in an aqueous medium, and then the organic solvent is removed. Although it does not specifically limit as a method of removing an organic solvent, The method of volatilizing an organic solvent using a rotary evaporator etc. is mentioned.

  After removing the organic solvent, coarse particles are removed by centrifugation, washed in a washing tank, and dried using a hot air dryer to obtain base particles.

  Other methods for removing the organic solvent include using a spray dryer, belt dryer, rotary kiln, etc., and a solution obtained by emulsifying or dispersing a solution obtained by dissolving or dispersing a toner material in an organic solvent in an aqueous medium. A method in which the organic solvent and the aqueous medium are volatilized by spraying inside is mentioned. Although it does not specifically limit as dry atmosphere, The air heated to the temperature beyond the boiling point of an organic solvent and an aqueous medium, nitrogen, a carbon dioxide gas, combustion gas, etc. are mentioned.

  Next, it is preferable to age the obtained base particles. Thereby, the hollow state inside the base particles can be controlled. At this time, the aging temperature is usually 30 to 55 ° C, preferably 40 to 50 ° C. The aging time is usually 5 to 36 hours, preferably 10 to 24 hours.

  In addition, when the particle size distribution of the base particles is wide, the particle size distribution can be narrowed by classification using a cyclone, a decanter, centrifugation, or the like.

  The toner of the present invention may be a base particle, but is a mixture of a base material particle and a fluidizing agent for assisting the fluidity, developability and chargeability of the toner using a Henschel mixer or the like. Is preferred. At this time, the toner of the present invention can be obtained by removing coarse particles with an ultrasonic sieve or the like, if necessary.

  Although it does not specifically limit as a fluidizing agent, An inorganic particle, the inorganic particle hydrophobized, etc. are mentioned, You may use 2 or more types together.

  The fluidizing agent preferably contains hydrophobic treated inorganic particles with an average primary particle size of 1 to 100 nm, and contains hydrophobic treated inorganic particles with an average primary particle size of 5 to 70 nm. Are more preferable, and it is particularly preferable to include hydrophobic treated inorganic particles having an average primary particle size of 20 nm or less and hydrophobic treated inorganic particles having an average primary particle size of 30 nm or more.

The fluidizing agent preferably has a specific surface area of 20 to 500 m ² / g as measured by the BET method.

  The inorganic particles preferably have an average primary particle size of 3 to 70 nm. If the average particle size of the primary particles is less than 3 nm, the inorganic particles may be buried in the base particles, and if it exceeds 70 nm, the surface of the photoreceptor may be damaged unevenly when developing with toner.

  The inorganic particles are not particularly limited, but silica, alumina, titania, barium titanate, magnesium titanate, calcium titanate, strontium titanate, iron oxide, copper oxide, zinc oxide, tin oxide, silica sand, clay, mica , Wollastonite, diatomaceous earth, chromium oxide, cerium oxide, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, silicon nitride, etc. May be. Of these, silica and titania are preferable.

  Examples of commercially available silica particles include HDK H 2000, HDK H 2000/4, HDK H 2050EP, HVK21, HDK H 1303 (manufactured by Hoechst), R972, R974, RX200, RY200, R202, R805, R812 (and above). , Manufactured by Nippon Aerosil Co., Ltd.).

  Commercially available titania particles include P-25 (manufactured by Nippon Aerosil Co., Ltd.), STT-30, STT-65C-S (above, manufactured by Titanium Industry Co., Ltd.), TAF-140 (manufactured by Fuji Titanium Industry Co., Ltd.), MT-150W. , MT-500B, MT-600B, MT-150A (manufactured by TEIKA CORPORATION) and the like.

  By subjecting the inorganic particles to a hydrophobic treatment, it is possible to suppress a decrease in toner flow characteristics and charging characteristics even under high humidity. The hydrophobizing agent is not particularly limited, but silane coupling agents such as methyltrimethoxysilane, methyltriethoxysilane, and octyltrimethoxysilane, silylating agents, silane coupling agents having a fluorinated alkyl group, and organic titanates. Examples of the coupling agent include an aluminum coupling agent, an aluminum coupling agent, and silicone oil.

  The silicone oil is not particularly limited, but dimethyl silicone oil, methylphenyl silicone oil, chlorophenyl silicone oil, methyl hydrogen silicone oil, alkyl-modified silicone oil, fluorine-modified silicone oil, polyether-modified silicone oil, alcohol-modified silicone oil, Amino-modified silicone oil, epoxy-modified silicone oil, epoxy-polyether-modified silicone oil, phenol-modified silicone oil, carboxyl-modified silicone oil, mercapto-modified silicone oil, (meth) acryl-modified silicone oil, α-methylstyrene-modified silicone oil, etc. Can be mentioned.

  Examples of the titania particles subjected to hydrophobic treatment include T-805 (manufactured by Nippon Aerosil Co., Ltd.), STT-30A, STT-65S-S (manufactured by Titanium Kogyo Co., Ltd.), TAF-500T, TAF-1500T (manufactured by Fuji Titanium). Kogyo Co., Ltd.), MT-100S, MT-100T (above, manufactured by Teika), IT-S (Ishihara Sangyo Co., Ltd.) and the like.

  The content of the fluidizing agent in the toner is usually 0.1 to 5% by mass, preferably 0.3 to 3% by mass.

  In the present invention, when the fluidizing agent and the base particles are mixed, a cleaning property improving agent for removing the toner after transfer remaining on the photoreceptor or the primary transfer medium may be added. The cleaning property improver is not particularly limited, but fatty acid metal salts such as zinc stearate, calcium stearate, and aluminum stearate; polycondensation such as polystyrene, (meth) acrylate copolymer, silicone resin, benzoguanamine, and nylon Examples thereof include resin particles such as a thermosetting resin. The resin particles can be produced by soap-free emulsion polymerization, suspension polymerization, dispersion polymerization or the like, and preferably have a relatively narrow particle size distribution and a volume average particle size of 0.01 to 1 μm.

  The average circularity of the toner of the present invention is preferably 0.93 to 0.99. When the average circularity is less than 0.93, the shape of the toner is too far from the spherical shape, so that the transferability is lowered and a high-quality image may not be obtained. On the other hand, if the average circularity exceeds 0.99, a cleaning failure may occur on the photoconductor or the transfer belt, and stains may occur on the image.

The average circularity of the toner is expressed by the formula (perimeter of a circle having the same area as that of the projected image of the toner) / (perimeter of the projected image of the toner).
Is the average value of circularity defined by.

  The average circularity is measured by using a flow particle image analyzer FPIA-2100 (manufactured by Sysmex Corporation), and is calculated by analysis using analysis software FPIA-2100 Data Processing Program for FPIA version 00-10. Can do.

  The toner of the present invention preferably has a shape factor SF-1 of 100 to 150. When SF-1 exceeds 150, the shape of the toner is deformed, and the toner movement during transfer is not smooth, and the toner behavior varies, so that high transfer efficiency cannot be obtained. Further, in addition to unstable charging of the toner, the toner may become brittle. As a result, the toner becomes fine powder in the developer, which causes a decrease in the durability of the developer.

  The toner of the present invention preferably has a shape factor SF-2 of 100 to 140. If SF-2 exceeds 140, transferability may be insufficient.

In addition, SF-1 and SF-2 are represented by the formula SF-1 = (L ² / A) × (π / 4) × 100
SF-2 = (P ² / A) × (1 / 4π) × 100
(In the formula, L is the absolute maximum length of the toner, A is the projected area of the toner, and P is the maximum peripheral length of the toner.)
Defined by The true sphere has both SF-1 and SF-2 of 100, and the value changes from spherical to indefinite as the value becomes larger than 100. SF-1 is a shape factor that represents the overall shape (ellipse, sphere, etc.), and SF-2 is a shape factor that indicates the degree of unevenness on the surface.

  SF-1 and SF-2 sampled 300 toners randomly from a photograph taken using a field emission type operation electron microscope S-4200 (manufactured by Hitachi, Ltd.), It can be calculated by introducing into an image analyzing apparatus Luzex AP (manufactured by Nireco) via an interface and analyzing.

  The toner of the present invention preferably has a weight average particle diameter of 2 to 7 μm, more preferably 2 to 5 μm. When the weight average particle diameter is less than 2 μm, when used as a one-component developer, toner filming on the developing roller and toner fusion to a member such as a blade for thinning the toner occur. There are things to do. Further, when used as a two-component developer, the toner may be fused to the surface of the carrier due to long-term stirring in the developing device, thereby reducing the charging ability of the carrier. On the other hand, when the weight average particle size exceeds 7 μm, it becomes difficult to form a high-resolution and high-quality image, and when used as a two-component developer, the balance of toner in the developer is performed. In some cases, the variation in the particle size of the toner may increase.

  In the toner of the present invention, the ratio of the weight average particle diameter to the number average particle diameter is preferably 1.00 to 1.25, and more preferably 1.00 to 1.15. If this ratio exceeds 1.25, the behavior of the toner varies during development, and the reproducibility of the fine dots is reduced, and a high-quality image may not be obtained.

  The weight average particle diameter and number average particle diameter of the toner can be measured using Coulter Multisizer II (manufactured by Coulter Inc.).

  The glass transition point of the toner of the present invention is usually 40 to 70 ° C., preferably 45 to 55 ° C. When the glass transition point is less than 40 ° C., the heat-resistant storage stability of the toner may be lowered, and when it exceeds 70 ° C., the low-temperature fixability may be lowered.

The temperature TG ′ at which the storage elastic modulus becomes 1 × 10 ⁴ dyne / cm ² when the frequency of the toner of the present invention is 20 Hz is usually 100 ° C. or higher, and preferably 110 to 200 ° C. When TG ′ is less than 100 ° C., the hot offset resistance may be lowered.

The temperature Tη at which the viscosity is 1 × 10 ³ poise when the frequency of the toner of the present invention is 20 Hz is usually 180 ° C. or less, and preferably 90 to 160 ° C. When Tη exceeds 180 ° C., the low-temperature fixability may deteriorate.

  TG′-Tη is usually 0 to 100 ° C., preferably 10 to 90 ° C., more preferably 20 to 80 ° C. If TG′−Tη is less than 0 ° C., it may be difficult to achieve both low-temperature fixability and hot offset resistance, and if it exceeds 100 ° C., heat-resistant storage stability may be reduced.

  The developer of the present invention includes the toner of the present invention and a carrier, and the mass ratio of the toner to the carrier is preferably 1 to 10%.

  The carrier is not particularly limited, and examples thereof include iron powder, ferrite powder, and magnetite powder having a particle size of 20 to 200 μm.

  The surface of the carrier may be coated with a resin. Examples of such resins include, but are not limited to, urea-formaldehyde resins, melamine resins, benzoguanamine resins, urea resins, polyamide resins, epoxy resins and other amino resins; polymethyl methacrylate, polyacrylonitrile and other acrylic resins; Polyvinyl resins such as vinyl acetate, polyvinyl alcohol and polyvinyl butyral; Polystyrene resins such as polystyrene and styrene-acrylic copolymers; Halogenated olefins such as polyvinyl chloride; Polyesters such as polyethylene terephthalate and polybutylene terephthalate; Polycarbonates; Polyethylenes ; Polyvinyl fluoride, polyvinylidene fluoride, polytrifluoroethylene, polyhexafluoropropylene, a copolymer of vinylidene fluoride and an acrylic monomer, vinyl fluoride A copolymer of isopropylidene and vinyl fluoride, fluorine resin terpolymers, etc. of tetrafluoroethylene and vinylidene fluoride and non-fluorinated monomer; and silicone resins.

  Such a resin may contain conductive powder or the like. The conductive powder is not particularly limited, and examples thereof include metal powder, carbon black, titanium oxide, tin oxide, and zinc oxide.

  The conductive powder preferably has an average particle size of 1 μm or less. When the average particle size exceeds 1 μm, it may be difficult to control the electric resistance.

  The toner of the present invention can be used as a magnetic toner or a non-magnetic toner without using a carrier.

  The image forming method of the present invention comprises a step of forming an electrostatic latent image on an electrostatic latent image carrier, a step of developing the electrostatic latent image using the developer of the present invention to form a toner image, and a toner A step of transferring the image to the recording medium, and a step of fixing the toner image transferred to the recording medium.

In the present invention, the toner image is preferably fixed by pressing the recording medium onto which the toner image has been transferred with a surface pressure of 10 to 150 N / cm ² . If the surface pressure for pressing the recording medium is less than 10 N / cm ² , the fixing strength of the toner image may be insufficient when fixing at a low temperature. If the surface pressure exceeds 150 N / cm ² , the recording medium may curl. Or the image quality may deteriorate.

  The surface pressure for pressurizing the recording medium can be measured using a pressure distribution measuring device PINCH (manufactured by Nitta).

The system speed is preferably 500 to 2.5 × 10 ³ mm / second. If the system speed is less than 500 mm / second, an image cannot be formed at a high speed, and in addition, the fixing nip time (nip width / system speed) becomes long, so that hot offset may occur. On the other hand, when the system speed exceeds 2.5 × 10 ³ mm / second, the fixing nip time is shortened, and the fixing property may be insufficient.

The system speed v [mm / second] is measured by measuring the time t [second] required to continuously form 100 sheets of A4 paper in the vertical direction, and the equation v = 100 × 297 / t
It is requested from. The length of the A4 paper in the paper passing direction is 297 mm.

  FIG. 2 shows an example of an image forming apparatus used in the present invention. The image forming apparatus 100 is a tandem color image forming apparatus, and includes a copying apparatus main body 150, a paper feed table 200, a scanner 300, and an automatic document feeder (ADF) 400.

  The intermediate transfer belt 50 provided at the center of the copying apparatus main body 150 is an endless belt stretched around three rollers 14, 15 and 16, and can move in the direction of the arrow in the figure. In the vicinity of the roller 15, a cleaning device 90 having a cleaning blade for removing the toner remaining on the intermediate transfer belt 50 on which the toner image is transferred onto the recording paper is disposed. The image forming units 120Y, 120C, 120M, and 120K for yellow, cyan, magenta, and black are juxtaposed along the conveyance direction while facing the intermediate transfer belt 50 stretched by the rollers 14 and 15. An exposure device 30 is disposed in the vicinity of the image forming unit 120. Further, the transfer belt 24 is disposed on the side of the intermediate transfer belt 50 opposite to the side on which the image forming unit 120 is disposed. The transfer belt 24 is an endless belt stretched around a pair of rollers 22 and 23, and the recording paper conveyed on the transfer belt 24 and the intermediate transfer belt 50 are in contact between the rollers 16 and 22. be able to. Also, a fixing device 25 including a fixing belt 26 that is an endless belt stretched around a pair of rollers and a pressure roller 27 that is pressed against the fixing belt 26 is disposed in the vicinity of the transfer belt 24. Has been. A sheet reversing device 28 for reversing the recording paper when an image is formed on both sides of the recording paper is disposed in the vicinity of the transfer belt 24 and the fixing device 25.

  Next, a method for forming a full-color image using the image forming apparatus 100 will be described. First, a color document is set on the document table 130 of the automatic document feeder (ADF) 400, or the automatic document feeder 400 is opened and a color document is set on the contact glass 32 of the scanner 300 to automatically convey the document. The device 400 is closed. When a start switch (not shown) is pressed, when an original is set on the automatic document feeder 400, the original is conveyed and moved onto the contact glass 32, and then the original is set on the contact glass 32. In this case, the scanner 300 is immediately driven, and the first traveling body 33 including the light source and the second traveling body 34 including the mirror travel. At this time, the reflected light from the original surface of the light irradiated from the first traveling body 33 is reflected by the second traveling body 34 and then received by the reading sensor 36 via the imaging lens 35, whereby the original is received. It is read and image information of black, yellow, magenta and cyan is obtained.

  The image information for each color is transmitted to the image forming unit 120 for each color, and a toner image for each color is formed. As shown in FIG. 3, each color image forming unit 120 develops the photosensitive drum 10, the charging roller 20 for uniformly charging the photosensitive drum 10, and the electrostatic latent image with each color developer. A developing device 40 for forming toner images of respective colors, a transfer roller 80 for transferring the toner image onto the intermediate transfer belt 50, a cleaning device 60 having a cleaning blade, and a charge eliminating lamp 70.

  The toner images of the respective colors formed by the image forming units 120 of the respective colors are sequentially transferred (primary transfer) onto the intermediate transfer body 50 that is stretched and moved by the rollers 14, 15, and 16, and superimposed to form a composite toner image. It is formed.

  On the other hand, in the paper feed table 200, one of the paper feed rollers 142 is selectively rotated to feed recording paper from one of the paper feed cassettes 144 provided in multiple stages in the paper bank 143, and one sheet at a time by the separation roller 145. The paper is separated and sent to the paper feed path 146, transported by the transport roller 147, guided to the paper feed path 148 in the copying machine main body 150, and abutted against the registration roller 49 to stop. Alternatively, the paper feed roller 51 is rotated to feed out the recording paper on the manual feed tray 54, separated one by one by the separation roller 52, guided to the manual paper feed path 53, and abutted against the registration roller 49 and stopped. The registration roller 49 is generally used while being grounded, but may be used in a state where a bias is applied in order to remove paper dust from the recording paper. Next, by rotating the registration roller 49 in synchronization with the composite toner image formed on the intermediate transfer belt 50, the recording paper is sent between the intermediate transfer belt 50 and the transfer belt 24, and the composite toner image is sent. Is transferred onto the recording paper (secondary transfer). The toner remaining on the intermediate transfer belt 50 to which the composite toner image has been transferred is removed by the cleaning device 90.

  The recording paper onto which the composite toner image has been transferred is conveyed by the transfer belt 24 and then the composite toner image is fixed by the fixing device 25. Next, the conveyance path of the recording paper is switched by the switching claw 55 and the recording paper is discharged onto the paper discharge tray 57 by the discharge roller 56. Alternatively, the recording path of the recording paper is switched by the switching claw 55, reversed by the sheet reversing device 28, an image is similarly formed on the back side, and then discharged onto the discharge tray 57 by the discharge roller 56. .

  The image forming apparatus 100 sequentially transfers (primary transfer) the toner images of the respective colors formed by the image forming units 120 of the respective colors onto the intermediate transfer body 50 and superimposes them, and then transfers them onto the recording paper (secondary transfer). However, it is also possible to use a direct transfer system in which the toner images of the respective colors formed by the image forming units 120 of the respective colors are sequentially transferred onto the recording paper and superimposed.

  Further, a transfer roller may be used instead of the transfer belt 24.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not limited to this. Hereinafter, a part shows a mass part.

[Prepolymer synthesis]
In a reaction vessel equipped with a cooling pipe, a stirrer and a nitrogen introduction pipe, 682 parts of bisphenol A ethylene oxide 2-mole adduct, 81 parts of bisphenol A propylene oxide 2-mole adduct, 283 parts of terephthalic acid, trimellitic anhydride 22 parts of acid and 2 parts of dibutyltin oxide were added, reacted at 230 ° C. under normal pressure for 7 hours, and then reacted under reduced pressure of 10 to 15 mmHg for 5 hours to obtain an intermediate polyester 1. The intermediate polyester 1 had a number average molecular weight of 2200, a weight average molecular weight of 9700, a glass transition point of 54 ° C., an acid value of 0.5 KOH mg / g, and a hydroxyl value of 52 KOH mg / g.

  Next, 410 parts of intermediate polyester 1, 89 parts of isophorone diisocyanate and 500 parts of ethyl acetate are placed in a reaction vessel equipped with a cooling pipe, a stirrer and a nitrogen introduction pipe, and reacted at 100 ° C. for 5 hours to produce a prepolymer. 1 was obtained. Prepolymer 1 had a free isocyanate content of 1.53% by mass.

[Synthesis of ketimine]
In a reaction vessel equipped with a stirrer and a thermometer, 170 parts of isophoronediamine and 75 parts of methyl ethyl ketone were charged and reacted at 50 ° C. for 4 and a half hours to obtain ketimine 1. Ketimine 1 had an amine value of 417 KOH mg / g.

[Example 1]
In a reaction vessel equipped with a stirring bar and a thermometer, 683 parts of ion-exchanged water, 11 parts of sodium salt Eleminol RS-30 (manufactured by Sanyo Kasei Kogyo Co., Ltd.) of sulfuric acid ester of methacrylic acid ethylene oxide, 10 parts of polylactic acid, 60 parts of styrene, 100 parts of methacrylic acid, 70 parts of butyl acrylate, and 1 part of ammonium persulfate were charged and stirred at 3.8 × 10 ³ rpm for 30 minutes. Next, after heating up to 75 degreeC and making it react for 4 hours, 30 mass parts of 1 mass% ammonium persulfate aqueous solution was added, and it age | cure | ripened at 75 degreeC for 6 hours, and obtained the resin particle dispersion 1. The volume average particle diameter of the resin particle dispersion 1 was measured using a laser diffraction / scattering particle size distribution analyzer LA-920 (manufactured by Horiba, Ltd.). Moreover, when the resin of the resin particle dispersion 1 was isolated, the glass transition point was 59 ° C. and the weight average molecular weight was 6 × 10 ⁴ .

  990 parts of ion-exchanged water, 83 parts of resin particle dispersion 1, 37 parts of a 48.3% by weight aqueous solution of sodium dodecyl diphenyl ether disulfonate, Eleminol MON-7 (manufactured by Sanyo Chemical Industries) and 90 parts of ethyl acetate are mixed and stirred. A milky white aqueous medium 1 was obtained.

In a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen introduction tube, 229 parts of bisphenol A ethylene oxide 2 mol adduct, 329 parts of bisphenol A propylene oxide 3 mol adduct, 208 parts terephthalic acid, 80 parts adipic acid And 2 parts of dibutyltin oxide were added and reacted at 230 ° C. for 7 hours under normal pressure, and then reacted for 5 hours under reduced pressure of 10 to 15 mmHg. Next, 35 parts of trimellitic anhydride was added and reacted at 180 ° C. for 2 hours under normal pressure to obtain polyester 1. Polyester 1 had a number average molecular weight of 2.0 × 10 ³ , a weight average molecular weight of 3.8 × 10 ³ , a glass transition point of 40 ° C., and an acid value of 25 KOH mg / g.

  Using Henschel mixer (made by Mitsui Mining Co.), 1200 parts of ion-exchanged water, 540 parts of carbon black Printex 35 (made by Dexa) having a DBP oil absorption of 42 ml / 100 mg, pH 9.5 and 1200 parts of polyester 1. After mixing and kneading at 110 ° C. for 1 hour using two rolls, rolling and cooling were performed, and the mixture was pulverized with a pulverizer to obtain master batch 1.

  In a container equipped with a stir bar and a thermometer, 378 parts of polyester 1, 100 parts of paraffin wax with a glass transition point of 71 ° C. and 947 parts of ethyl acetate are charged, heated to 80 ° C. and kept for 5 hours while stirring. Then, it was cooled to 30 ° C. in 1 hour. Next, 500 parts of Masterbatch 1 and 500 parts of ethyl acetate were added and mixed for 1 hour. 1324 parts of the obtained mixed liquid was transferred to a container, and using a bead mill Ultra Visco Mill (manufactured by Imex), the liquid feeding speed was 1 kg / hour, the peripheral speed of the disk was 6 m / second, and the particle size was 0.5 mm. 80% by volume of zirconia beads were filled and dispersed under conditions of 3 passes. Next, 1324 parts of a 65% by mass ethyl acetate solution of polyester 1 was added, and two passes were performed using a bead mill under the above conditions to obtain dispersion 1. When dispersion 1 was dried at 130 ° C. for 30 minutes, the solid content concentration was 50% by mass.

749 parts of dispersion 1, 115 parts of prepolymer 1 and 2.9 parts of ketimine 1 were placed in a container and mixed for 2 minutes at 5 × 10 ³ rpm using a TK homomixer (manufactured by Tokushu Kika). Thereafter, 1200 parts of the aqueous medium 1 was added and mixed at 1.3 × 10 ⁴ rpm for 25 minutes using a TK homomixer to obtain an emulsified slurry 1.

  The emulsified slurry 1 was put into a container in which a stirrer and a thermometer were set, and after removing the solvent at 30 ° C. for 8 hours, it was aged at 40 ° C. for 24 hours to obtain a dispersed slurry 1.

After 100 parts of the dispersion slurry 1 were filtered under reduced pressure, 100 parts of ion-exchanged water was added to the filter cake, and the mixture was mixed for 10 minutes at 1.2 × 10 ⁴ rpm using a TK homomixer, followed by filtration. To the obtained filter cake, 100 parts of a 10% by mass aqueous sodium hydroxide solution was added, and the mixture was mixed at 1.2 × 10 ⁴ rpm for 30 minutes using a TK homomixer, and then filtered under reduced pressure. 100 parts of 10% by mass hydrochloric acid was added to the obtained filter cake, and the mixture was mixed for 10 minutes at 1.2 × 10 ⁴ rpm using a TK homomixer, followed by filtration. To the obtained filter cake, 300 parts of ion-exchanged water was added, and after mixing for 10 minutes at 1.2 × 10 ⁴ rpm using a TK homomixer, an operation of filtering was performed twice to obtain a filter cake.

  The obtained filter cake was dried at 45 ° C. for 48 hours using a circulating dryer, and then sieved with a mesh having an opening of 75 μm to obtain base particles.

  100 parts of the obtained base particles and 1 part of hydrophobized silica having a particle diameter of 13 nm were mixed using a Henschel mixer to obtain a toner.

[Example 2]
In a reaction vessel equipped with a stirring bar and a thermometer, 683 parts of ion-exchanged water, 11 parts of sodium salt Eleminol RS-30 (manufactured by Sanyo Kasei Kogyo Co., Ltd.) of sulfuric acid ester of methacrylic acid ethylene oxide, 10 parts of polylactic acid, 60 parts of styrene, 100 parts of methacrylic acid, 70 parts of butyl acrylate and 1 part of ammonium persulfate were charged and stirred at 3.8 × 10 ³ rpm for 20 minutes. Next, after heating up to 75 degreeC and making it react for 3 hours, 30 mass parts of 1 mass% ammonium persulfate aqueous solution was added and it age | cure | ripened at 65 degreeC for 12 hours, and the resin particle dispersion liquid 2 was obtained. The volume average particle diameter of the resin particle dispersion 2 was measured using a laser diffraction / scattering particle size distribution analyzer LA-920 (manufactured by Horiba Ltd.), and it was 390 nm. Moreover, when the resin of the resin particle dispersion 2 was isolated, the glass transition point was 60 ° C. and the weight average molecular weight was 7 × 10 ⁴ .

  A toner was obtained in the same manner as in Example 1 except that the resin particle dispersion 2 was used instead of the resin particle dispersion 1.

[Example 3]
In a reaction vessel equipped with a stirring bar and a thermometer, 683 parts of ion-exchanged water, 11 parts of sodium salt Eleminol RS-30 (manufactured by Sanyo Kasei Kogyo Co., Ltd.) of sulfuric acid ester of methacrylic acid ethylene oxide, 10 parts of polylactic acid, 60 parts of styrene, 100 parts of methacrylic acid, 70 parts of butyl acrylate and 1 part of ammonium persulfate were charged and stirred at 2.0 × 10 ³ rpm for 20 minutes. Next, after heating up to 75 degreeC and making it react for 3 hours, 30 mass parts of 1 mass% ammonium persulfate aqueous solution was added and it age | cure | ripened at 65 degreeC for 12 hours, and the resin particle dispersion liquid 3 was obtained. The volume average particle diameter of the resin particle dispersion 3 was measured using a laser diffraction / scattering particle size distribution analyzer LA-920 (manufactured by Horiba Ltd.), and it was 640 nm. Further, when the resin of the resin particle dispersion 3 was isolated, the glass transition point was 59 ° C. and the weight average molecular weight was 1.2 × 10 ⁵ .

In a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen introduction tube, 229 parts of an ethylene oxide 2-mole adduct of bisphenol A, 264 parts of a propylene oxide 3-mole adduct of bisphenol A, 208 parts of terephthalic acid, 80 parts of adipic acid And 2 parts of dibutyltin oxide were added and reacted at 230 ° C. for 9 hours under normal pressure, and then allowed to react for 5 hours under reduced pressure of 10 to 15 mmHg. Next, 35 parts of trimellitic anhydride was added and reacted at 180 ° C. for 2 hours under normal pressure to obtain polyester 2. Polyester 2 had a number average molecular weight of 1.8 × 10 ³ , a weight average molecular weight of 3.5 × 10 ³ , a glass transition point of 38 ° C., and an acid value of 25 KOH mg / g.

  A toner was obtained in the same manner as in Example 1 except that the resin particle dispersion 3 and the polyester 2 were used instead of the resin particle dispersion 1 and the polyester 1.

[Example 4]
A toner was obtained in the same manner as in Example 1 except that polyester 2 was used instead of polyester 1.

[Comparative Example 1]
In a reaction vessel equipped with a stirring bar and a thermometer, 683 parts of ion-exchanged water, 11 parts of sodium salt Eleminol RS-30 (manufactured by Sanyo Kasei Kogyo Co., Ltd.) of sulfuric acid ester of methacrylic acid ethylene oxide, 10 parts of polylactic acid, 60 parts of styrene, 100 parts of methacrylic acid, 70 parts of butyl acrylate, and 1 part of ammonium persulfate were charged and stirred at 3.8 × 10 ³ rpm for 30 minutes. Next, after heating up to 75 degreeC and making it react for 4 hours, 30 mass parts of 1 mass% ammonium persulfate aqueous solution was added, and it age | cure | ripened at 75 degreeC for 6 hours, and obtained the resin particle dispersion liquid 4. The volume average particle diameter of the resin particle dispersion 4 was measured using a laser diffraction / scattering particle size distribution analyzer LA-920 (manufactured by Horiba Ltd.), and it was 105 nm. Further, when the resin of the resin particle dispersion 4 was isolated, the glass transition point was 58 ° C. and the weight average molecular weight was 1.4 × 10 ⁵ .

  A toner was obtained in the same manner as in Example 1 except that the resin particle dispersion 4 was used instead of the resin particle dispersion 1. The toner did not have a core-shell structure.

[Comparative Example 2]
In a reaction vessel equipped with a stirring bar and a thermometer, 683 parts of ion-exchanged water, 11 parts of sodium salt Eleminol RS-30 (manufactured by Sanyo Kasei Kogyo Co., Ltd.) of sulfuric acid ester of methacrylic acid ethylene oxide, 10 parts of polylactic acid, 60 parts of styrene, 100 parts of methacrylic acid, 70 parts of butyl acrylate and 1 part of ammonium persulfate were charged and stirred at 1.5 × 10 ³ rpm for 20 minutes. Next, after heating up to 75 degreeC and making it react for 3 hours, 30 mass parts of 1 mass% ammonium persulfate aqueous solution was added, and it age | cure | ripened at 65 degreeC for 12 hours, and obtained the resin particle dispersion 5. The volume average particle size of the resin particle dispersion 5 was measured using a laser diffraction / scattering particle size distribution analyzer LA-920 (manufactured by Horiba Ltd.), and it was 720 nm. Further, when the resin of the resin particle dispersion 5 was isolated, the glass transition point was 57 ° C. and the weight average molecular weight was 1.2 × 10 ⁵ .

  A toner was obtained in the same manner as in Example 1 except that the resin particle dispersion 5 was used instead of the resin particle dispersion 1.

[Comparative Example 3]
In a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen introduction tube, 229 parts of bisphenol A ethylene oxide 2 mol adduct, 529 parts of bisphenol A propylene oxide 3 mol adduct, 208 parts terephthalic acid, 46 parts adipic acid And 2 parts of dibutyltin oxide were added and reacted at 230 ° C. for 10 hours under normal pressure, and then allowed to react for 8 hours under reduced pressure of 10 to 15 mmHg. Next, 70 parts of trimellitic anhydride was added and reacted at 180 ° C. for 3 hours under normal pressure to obtain polyester 3. Polyester 3 had a number average molecular weight of 2.8 × 10 ³ , a weight average molecular weight of 7.3 × 10 ³ , a glass transition point of 47 ° C., and an acid value of 25 KOH mg / g.

  A toner was obtained in the same manner as in Example 1 except that polyester 3 was used instead of polyester 1.

  Table 1 shows the physical properties of the obtained toner.

トナーの物性の評価方法を以下に示す。

A method for evaluating the physical properties of the toner is shown below.

(Core softening index Ct and shell thermal hardness St)
Evaluation was performed using a flow tester CFT-500D (manufactured by Shimadzu Corporation). Specifically, first, 1 g of toner was pressure-molded into a cylindrical shape having a diameter of 1 cm to obtain a tableted toner T. Next, as shown in FIG. 1A, the tableted toner T placed in the cylinder C was preheated for 200 seconds, and the temperature was raised to T _s (50 ° C.). Further, while applying a constant load (2~25kg) by the plunger P, by raising the temperature to flow ending temperature T _end the heating element H at 3 ° C. / min, flow out of the toner T 'which is melted from a die D Then, as shown in FIG. 1 (b), the descending amount of the plunger P with respect to the temperature of the heating element H was measured. A die having a diameter of 0.5 mm and a length of 1.0 mm was used.

(Shell thickness)
After the toner was embedded in an epoxy resin and cured, the shell and the core were subjected to differential dyeing by gas exposure with ruthenium tetroxide for 5 minutes. Next, a section was cut out with a knife, and an ultrathin section of toner having a thickness of 200 nm was prepared using an ultramicrotome ULTRACUT UCT (manufactured by Leica). Further, using a TEM (Transmission Electron Microscope) H7000 (manufactured by Hitachi High-Tech), an ultrathin section of the toner was observed at an acceleration voltage of 100 kV, and the thickness of the shell was measured. At this time, the thickness of the shell of the toner 10 particles was measured, and the average value was calculated.

(Average circularity)
The average circularity was measured using a flow particle image analyzer FPIA-2100 and analysis software FPIA-2100 Data Processing Program for FPIA version 00-10 (manufactured by Sysmex Corporation). Specifically, first, in a 100 ml beaker made of glass, 10% by weight surfactant (alkylbenzene sulfonate) Neogen SC-A (Daiichi Kogyo Seiyaku Co., Ltd.) 0.1-0.5 ml and toner 0.1 After adding 0.5 g and stirring with a microspatel, 80 ml of ion-exchanged water was added. The average circularity was measured when the obtained dispersion was dispersed for 3 minutes using an ultrasonic disperser (manufactured by Honda Electronics Co., Ltd.) and the concentration was 5000 to 15000 / μl.

(Shape factors SF-1 and SF-2)
300 SEM images of toner imaged using FE-SEM (S-4200) (manufactured by Hitachi, Ltd.) were randomly sampled, and the image information was sent to an image analyzer Luzex AP (Nireco) via the interface. And the shape factors SF-1 and SF-2 were calculated.

(Number average particle diameter Dn and weight average particle diameter D ₄ )
The number average particle diameter and the weight average particle diameter were measured using Coulter Multisizer II (manufactured by Coulter Inc.). Specifically, first, 0.1 to 5 ml of a surfactant (polyoxyethylene alkyl ether) was added to 100 to 150 ml of the electrolytic solution ISOTON-II (manufactured by Coulter). Next, 2 to 20 mg of toner was added and dispersed using an ultrasonic disperser for about 1 to 3 minutes. The number average particle diameter and the weight average particle diameter of the obtained sample dispersion were measured using a 100 μm aperture. In addition, as a channel, it is 2.00-2.52 micrometers; 2.52-3.17 micrometers; 3.17-4.00 micrometers; 4.00-5.04 micrometers; 5.04-6.35 micrometers; 6.35- 8.00 to 10.08 μm; 10.08 to 12.70 μm; 12.70 to 16.00 μm; 16.00 to 20.20 μm; 20.20 to 25.40 μm; 25.40 to 32. 00 μm; 13 channels of 32.00 to 40.30 μm were used, and particles having a particle size of 2.00 to 40.30 μm were measured.

[Creation of carrier]
Using a stirrer, 450 parts of toluene, 450 parts of silicone resin SR2400 (made by Toray Dow Corning Silicone Co., Ltd.) with a nonvolatile content of 50% by mass, 10 parts of aminosilane SH6020 (made by Toray Dow Corning Silicone Co., Ltd.) and 10 parts of carbon black are used. For 10 minutes to prepare a coating layer coating solution. The obtained coating solution for coating layer and 5000 parts of Mn ferrite having a weight average particle diameter of 35 μm are put into a coating apparatus in which a rotating bottom plate disk and a stirring blade are provided in a fluidized bed to form a swirling flow. The coating layer coating solution was applied to Mn ferrite. Next, using an electric furnace, firing was performed at 250 ° C. for 2 hours to obtain a carrier on which a coating layer having an average thickness of 0.5 μm was formed.

[Production of developer]
100 parts of the carrier and 7 parts of the toner were uniformly mixed and charged using a type of tumbler mixer in which the container was rolled and stirred to obtain a developer.

[Developer evaluation]
The developer was evaluated using a modified image development section and fixing section of imgio MP C7500. Specifically, the developing gap was 1.26 mm, the doctor blade gap was 1.6 mm, and the reflective photosensor function was turned off so that the system speed was 1700 mm / sec. The fixing unit of the fixing unit had a surface pressure of 39 N / cm ² and a fixing nip width of 10 mm with which the fixing roll pressed the recording paper on which the toner image was transferred. In addition, as a fixing roll, a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) was applied to the surface and molded to adjust the surface. Further, the actual temperature range of the photosensitive member, the developing device, and the transfer device was controlled to be 30 to 45 ° C. Further, the heating temperature of the fixing roll was set to 150 ° C.

  Table 2 shows the evaluation results of the developer.

現像剤の評価方法を以下に示す。

The developer evaluation method is shown below.

(Low temperature fixability)
After continuously outputting 20,000 charts having an image area ratio of 3%, the temperature of the fixing roll was changed by 5 ° C. to form an image, thereby evaluating the low temperature fixability. Specifically, after forming an image so that the image density measured using X-Rite 938 is 1.2, the image is rubbed 10 times using a clock meter equipped with a sand eraser and rubbed. The temperature at which the density becomes 70% or more of the image density before rubbing was defined as the minimum fixing temperature. At this time, a full color PPC paper type 6200 (manufactured by Ricoh) was used as the recording paper. Compared with the conventional system (image MPC6000), the fixing lower limit temperature is 20 ° C. or more lower, ◎ 10 ° C. to 20 ° C. lower, ○ 0 ° C. or more lower than 10 ° C. △, higher The thing was judged as x.

(Heat resistant storage stability)
Using a tapping device, a 20 ml glass container containing 10 g of toner is tapped 100 times and then stored in a high temperature and high humidity environment (55 ° C., 80% RH) or a low temperature and low humidity environment (10 ° C., 15% RH) for 48 hours. Then, the penetration was measured using a penetration tester (the conditions described in the Nikka Engineering Manual). Of the high-temperature and high-humidity environment and the low-temperature and low-humidity environment, the smaller penetration value is 20 mm or more, ◎, 15 mm or more and less than 20 mm, ◯, 10 mm or more and less than 15 mm, A case where the thickness was less than 10 mm was determined as x.

(Development stability)
Development stability was evaluated by continuously outputting 10,000 charts with an image area ratio of 3% and 60% and measuring the change in the charge amount of the toner using the blow-off method. Specifically, the developer was placed in a cylindrical Faraday cage having a metal mesh disposed at both ends, the toner was detached from the developer with high-pressure air, and the charge remaining on the toner was measured using an electrometer. At this time, the toner mass was determined from the mass difference of the Faraday cage before and after blow-off. Among the image area ratios of 3% and 60%, the one with the larger change in the charge amount of the toner is less than 5 μC / g, the one with 5 μC / g or more and less than 10 μC / g is Δ, 10 μC / g Determination was made with x being g or more.

(Wound)
After continuous output of 20,000 charts having an image area ratio of 3%, the temperature of the fixing roll was changed by 5 ° C. to form an image, and winding was evaluated. At this time, a full color PPC paper type 6200 (manufactured by Ricoh) was used as the recording paper. Compared with the conventional system (image MPC6000), the temperature at which the winding occurs is 20 ° C. or more higher, ◎ 10 ° C. or higher and less than 20 ° C. higher, 0 ° C. or higher and lower than 10 ° C. higher Δ The lower one was judged as x.

DESCRIPTION OF SYMBOLS 10 Photosensitive drum 20 Charging roller 24 Transfer belt 25 Fixing apparatus 30 Exposure apparatus 40 Developing apparatus 50 Intermediate transfer belt 60 Cleaning apparatus 70 Static elimination lamp 80 Transfer roller 100 Image forming apparatus 100 'Process cartridge

JP 2006-267231 A

Claims (12)

A toner having host particles,
The base particle has a core-shell structure including a core containing a binder resin and a release agent, and a shell having a thickness of 0.01 μm or more and 2 μm or less,
The core has a softening index of 60 ° C. or more and 85 ° C. or less,
The toner according to claim 1, wherein the shell has a thermal hardness of 0.7 to 1.8.   The toner according to claim 1, wherein the shell includes resin particles.   The toner according to claim 1, wherein the binder resin contains polyester and / or urea-modified polyester.   The base particles are obtained by emulsifying or dispersing a liquid obtained by dissolving or dispersing a toner material containing a polyester prepolymer having an isocyanate group in an organic solvent in an aqueous medium, and then adding the polyester prepolymer and a compound having an amino group. The toner according to claim 3, wherein the toner is formed by adding the toner.   The toner according to claim 4, wherein the aqueous medium includes resin particles.   The toner according to claim 4, wherein the toner material further contains polyester.   The toner according to claim 1, wherein the average circularity is 0.93 or more and 0.99 or less. The shape factor SF-1 is 100 or more and 150 or less,
The toner according to any one of claims 1 to 7, wherein the shape factor SF-2 is 100 or more and 140 or less. The weight average particle size is 2 μm or more and 7 μm or less,
The toner according to claim 1, wherein the ratio of the weight average particle diameter to the number average particle diameter is 1.00 or more and 1.25 or less.   A developer comprising the toner according to claim 1 and a carrier. Forming an electrostatic latent image on the electrostatic latent image carrier;
Developing the electrostatic latent image with the developer according to claim 10 to form a toner image;
Transferring the toner image to a recording medium;
An image forming method comprising a step of fixing a toner image transferred to the recording medium. The recording medium on which the toner image has been transferred is pressed at a surface pressure of 10 N / cm ² or more and 150 N / cm ² or less to fix the toner image,
The image forming method according to claim 11, wherein the system speed is 500 mm / second or more and 2.5 × 10 ³ mm / second or less.

Images