JP5233118B2 - Image forming method - Google Patents

Description

  The present invention relates to an image forming method.

  In the field of electrophotographic image forming technology, with the advancement of digitization technology, high-quality image formation that faithfully reproduces fine dot images and high-definition images is required. Consideration is being made. A so-called polymerization toner capable of controlling the shape and size of the particles in the manufacturing process has attracted attention.

  This polymerized toner is obtained by agglomerating resin particles obtained through a polymerization process such as an emulsion polymerization method, toner particles such as colorant particles, and other particles as necessary. Toner particles.

  As one of the resin particles constituting the polymerized toner, for example, styrene acrylic resin particles can be cited (for example, see Patent Documents 1 and 2).

  In addition, styrene acrylic resins can be kept low in softening temperature due to their amorphous structure, and can be suitably used for so-called low temperature fixing compatible toners that require fixing of toner images at relatively low temperatures. It is what

  However, a toner using a styrene acrylic resin is excellent in low-temperature fixability, but has low fixing strength. When a force such as bending, bending, or rubbing is applied to a toner image formed on a transfer material after fixing, Therefore, there is a problem that it is difficult to stably maintain the toner image. Therefore, stabilization was attempted by taking measures such as cross-linking the resin, but a sufficient effect was not obtained.

  On the other hand, there is a toner using a polyester resin. Toners using polyester resin have a higher softening point than those using vinyl resin, but can be melted sharply, and are stable even if force such as bending or bending is applied to the toner image after fixing. It has the merit that a firm toner image can be obtained.

  Against this background, the development of toners that have the advantages of both styrene acrylic resins and polyester resins has been studied for some time, including, for example, styrene-acrylic resins and polyester resins through kneading and grinding processes. The production technology of the toner to be used was studied. In this method, both resins are mixed, melted and kneaded, and then pulverized to produce a toner having a hybrid structure in which a styrene acrylic resin and a polyester resin are mixed. An attempt was made (for example, see Patent Document 3).

Recently, there has been a demand for reduction in energy consumption in image forming apparatuses from the viewpoint of global environmental conservation, etc. In addition to the development of toner for low-temperature fixing described above, improvement of fixing efficiency in fixing apparatuses is also being considered. ing. As one of such fixing devices, a fixing device having a belt-like heating body and a belt-like pressure body provided at the top and bottom has appeared in place of the conventional combination of a heating roller and a pressure roller ( For example, see Patent Document 4). In this fixing device, a belt-like member is used as a part to be heated and pressed, thereby widening the nip width at the fixing part and improving the fixing efficiency.
JP 2000-214629 A JP 2001-125313 A JP-A-6-3856 JP-A-7-140815

However, in the image forming apparatus provided with the fixing device having the belt-like heating body and the belt-like pressure body described above, image formation is performed using a pulverized toner obtained by mixing a polyester resin and a styrene acrylic resin. As the number of prints increased, contamination began to appear on the image. In particular, in cases where a large number of prints, such as over 10,000 sheets, are made, the surface of the heating roller is very dirty, and image contamination due to fixing offset is noticeable. Winding around the means also occurred.

The present invention provides a fixing offset when an image is formed using a toner having a polyester resin and a styrene acrylic resin in an image forming apparatus having a fixing device having a belt-shaped heating unit and a belt-shaped pressing unit. An object of the present invention is to provide an image forming method that does not cause image contamination due to the above.

  In particular, even in cases where a large amount of continuous printing exceeding 10,000 sheets, where fixing offset is likely to occur, good prints without image contamination can be obtained, and even on double-sided printing, the belt is wrapped around the heating means side. Therefore, an object of the present invention is to provide an image forming method capable of forming a good image without generating any problem.

  The present invention is achieved by adopting the following configuration.

1. In an image forming method having a step of fixing a toner image formed using toner composed of toner particles containing at least a resin and a colorant on a support using a contact heating type fixing device,
The resin constituting the toner particles contains a polyester resin and a styrene acrylic resin,
The toner particles are in an aqueous medium.
Radical polymerization containing at least one polycarboxylic acid and at least one polycondensable monomer containing a polyhydric alcohol, and at least one styrene compound and at least one (meth) acrylic acid ester compound mixed sex monomer to form oil droplets of the hybrid resin particle-forming composition, after forming the polyester resin by polycondensation between the polyhydric alcohol and the polyvalent carboxylic acid in the oil droplets, wherein A hybrid resin particle is obtained by radical copolymerization of a radical polymerizable monomer to form a styrene acrylic resin, and is obtained by aggregating at least the hybrid resin particle and the colorant particle in an aqueous medium. Yes,
An image forming method, wherein the contact heating type fixing device includes a belt-shaped heating unit and a belt-shaped pressing unit.
2. The polyester resin has a number average molecular weight (Mn) of 1,000 to 10,000 as measured by gel permeation chromatography. The image forming method described in 1.
3. The styrene acrylic resin has a number average molecular weight (Mn) measured by gel permeation chromatography of 1,000 to 100,000. Or the image forming method of 2.

According to the present invention, when an image is formed using a fixing device having a toner containing a polyester resin and a styrene acrylic resin , a belt-like heating means and a belt-like pressurizing means, fixing is performed. It has become possible to stably provide printed materials free from image contamination due to offset. In particular, even in the case of performing continuous printing over a large number of sheets exceeding 10,000 sheets, which is considered to cause fixing offset, good print production without image contamination can be performed.

  Furthermore, the printed material is not wrapped around the belt-like heating means even during double-sided printing.

Further, in the present invention by using a toner composed of hybrid resin particles of the polyester resin and styrene-acrylic resins, the expressed performance possessed by the polyester resins and styrene-acrylic resins, stable belt fixing is achieved. That is, a toner image having a stable fixing strength can be obtained due to the excellent viscoelasticity of the polyester resin, and the toner image can be fixed at a lower fixing temperature than before by the excellent low temperature fixing property due to the styrene acrylic resin. Yes.

  In addition, since these hybrid resin particles are manufactured through a specific polymerization process, a toner with a small particle size, no variation between particles, and a sharp charge distribution can be obtained. High-efficiency toner image fixing can be performed by this fixing device. Furthermore, a minute dot image and a fine line image are faithfully reproduced in the formed toner image, and it is possible to stably produce a high-quality image corresponding to digital image formation over a long period of time.

The present invention relates to an image forming method including a step of fixing a toner image developed with a toner containing a polyester resin and a styrene acrylic resin with a fixing device including a belt-shaped heating unit and a belt-shaped pressing unit. It is.

According to the present invention, when an image is formed using a fixing device having a toner containing a polyester resin and a styrene acrylic resin , a belt-shaped heating unit and a belt-shaped pressurizing unit, It is intended to make prints without causing image contamination.

The reason why the effect obtained in the present invention was not expressed in the pulverized toner using the polyester resin and the styrene acrylic resin in the prior art is probably the dispersibility of the polyester resin and the styrene acrylic resin in the pulverized toner. It is thought to be caused by That is, the pulverized toner cannot uniformly disperse the polyester resin and the styrene acrylic resin at the level realized by the toner used in the present invention, and a region having a low melt viscosity is partially formed. In a fixing device having a wide nip portion due to the belt, it is presumed that a region having a low melt viscosity moves to the surface of the heating belt and causes a fixing offset.

On the other hand, in the present invention, since a fine uniform dispersion structure of the polyester resin and the styrene acrylic resin is formed and a region having a low melt viscosity is not unevenly distributed in the toner, uniform softening even in a fixing device having a wide nip portion, It is assumed that melting is performed and stable fixing is realized.

  Hereinafter, the present invention will be described in detail.

(Image forming method)
In the image forming method of the present invention, at least a latent image formed on a photoreceptor is developed with a developer containing toner to form a toner image, and the toner image is transferred onto a transfer material. It includes a step of fixing a toner image on a transfer material using a contact heating type fixing device, and a step of cleaning residual toner remaining on the photoreceptor.

  Specifically, a step of forming an electrostatically formed latent image on the photosensitive member, a step of developing the latent image with a developer containing toner described later to form a toner image, and transferring the toner image A process of transferring to a transfer material by applying an electric field, and a toner image transferred on the transfer material is transferred using a contact heating type fixing device composed of a belt-like heating means and a belt-like pressure means described later. An image forming method including a step of fixing to a material and a step of cleaning residual toner remaining on the photoreceptor.

(toner)
The toner used in the image forming method according to the present invention is composed of a resin formed from hybrid resin particles made of a polyester resin and a styrene acrylic resin . The hybrid resin particles are obtained by further adding polyvalent carboxylic acid and polyhydric alcohol in an oil droplet containing styrene and acrylic acid ester or methacrylic acid ester in an aqueous medium. A polycondensation reaction is performed to form a polyester resin. A hybrid resin having a size of about 100 nm is obtained by mixing a polyester resin and a styrene acrylic resin by radical polymerization of the polymerizable monomer described above to form a styrene acrylic resin after the polyester resin is formed. Resin particles are produced.

  In the present invention, a carboxyl group of a polyvalent carboxylic acid and a hydroxyl group of a polyhydric alcohol in an oil droplet formed with a vinyl polymerizable monomer such as styrene or an acrylate ester finely dispersed in an aqueous medium. A polyester resin is formed by performing a dehydration reaction. In this way, an aqueous medium that tends to inhibit the progress of the esterification reaction by performing a polycondensation reaction using a system capable of blocking water such as oil droplets formed with a vinyl-based polymerizable monomer. It is estimated that the polyester resin is surely produced.

Then, the mixed resin particles containing the polyester resin and the styrene acrylic resin are aggregated to form colored particles as a toner base. Therefore, the polyester resin and the styrene acrylic resin are finely divided to a level that cannot be obtained with a pulverized toner. A uniformly dispersed toner is obtained. As described above, the toner used in the present invention realizes uniform dispersion of polyester resin and styrene acrylic resin, which have a different molecular structure and are very difficult to uniformly disperse, and further uses hybrid resin particles of 100 nm level. As a result, fine uniform dispersion is realized.

Therefore, since polyester resin and styrene acrylic resin are not unevenly distributed in the toner, even when using a fixing device with high fixing efficiency such as a belt type fixing device, uniform softening and melting can be performed, and fixing offset occurs. Stable fixing can be performed without concern.

  The toner according to the present invention is a polymerized toner obtained by a toner production method described in detail below, and a mixed resin particle containing both a polyester resin and a styrene acrylic resin is used as a colorant particle if necessary. And toner particles that are aggregated together.

Toner Production Method The toner production method according to the present invention is an aqueous system containing a surfactant (hereinafter, also referred to as “acidic group-containing surfactant”) comprising a compound having a long-chain hydrocarbon group and an acidic group. In the medium, it comprises at least one divalent or higher carboxylic acid (hereinafter referred to as “polyhydric carboxylic acid”) and at least one divalent or higher alcohol (hereinafter referred to as “polyhydric alcohol”). Forming oil droplets of a composite resin particle forming composition comprising a polycondensable monomer and a radical polymerizable monomer comprising at least one styrene compound and at least one (meth) acrylic ester compound A polycondensation step of polycondensation of polyvalent carboxylic acid and polyhydric alcohol in the oil droplets to obtain a polyester resin, and radical copolymerization of a radical polymerizable monomer A polymerization step of obtaining hybrid resin particles by performing a radical copolymerization step of obtaining a lenacrylic resin, and an aggregation step of aggregating at least the hybrid resin particles and the colorant particles in an aqueous medium to obtain toner particles. .

As an example of a method for producing such a toner,
(1) For the formation of hybrid resin particles by mixing a polycondensable monomer containing a polyvalent carboxylic acid and a polyhydric alcohol, and a radical polymerizable monomer containing a styrene compound and a (meth) acrylic ester compound An oil droplet forming step of preparing a composition and dispersing the composite resin particle-forming composition in an aqueous medium containing an acidic group-containing surfactant;
(2) a polymerization step of preparing a dispersion of hybrid resin particles by polymerizing an aqueous dispersion of the resulting composite resin particle forming composition;
(3) Aggregation step of aggregating and fusing the resulting composite resin particles, colorant particles and, if necessary, particles of toner constituents such as wax particles and charge control agent particles in an aqueous medium to obtain toner particles ,
(4) A filtration / washing process in which the obtained toner particles are filtered out from the aqueous medium, and the surfactant is washed away from the toner particles.
(5) A method comprising a drying step of the washed toner particles is mentioned,
(6) An external additive addition step of adding an external additive to the dried toner particles may be added.
(1) oil droplet forming step;
In the composite resin particle forming composition containing a polycarboxylic acid, a polyhydric alcohol, a styrene compound and a (meth) acrylic ester compound, an acidic group-containing surfactant having a concentration equal to or lower than the critical micelle concentration is dissolved. It is added to an aqueous medium and dispersed using mechanical energy to form oil droplets.

  Here, the disperser for dispersing oil droplets by mechanical energy is not particularly limited. For example, a stirring device “CLEARMIX” equipped with a rotor that rotates at high speed (CLEARMIX) (M Technique Co., Ltd.) )), An ultrasonic disperser, a mechanical homogenizer, a manton gourin, a pressure homogenizer, and the like.

  Moreover, it is preferable that a number average primary particle diameter shall be 50-500 nm in an oil drop, and, more preferably, it is 70-300 nm.

The “aqueous medium” in the present invention refers to a medium containing at least 50% by mass of 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. Among these, it is preferable to use an organic organic solvent such as methanol, ethanol, isopropanol, and butanol, which is an organic solvent that does not dissolve the resin.
[Acid group-containing surfactant]
The acidic group-containing surfactant used in the toner production method according to the present invention is a compound having a hydrophobic group composed of a long-chain hydrocarbon group and a hydrophilic group composed of an acidic group.

  Here, the “long-chain hydrocarbon group” means a hydrocarbon group having a main chain having 8 or more carbon atoms, and the long-chain hydrocarbon group has, for example, a carbon number. Examples thereof include an alkyl group having 8 to 40, an aromatic hydrocarbon group which may have an alkyl group as a substituent, and a phenyl group having an alkyl group having 8 to 30 carbon atoms is preferable.

  As the acidic group constituting the acidic group-containing surfactant, those having high acidity are preferable, and examples thereof include a sulfonic acid group, a carboxylic acid group, and a phosphoric acid group. Among these, a sulfonic acid group is preferable.

  Specific preferred examples of the acidic group-containing surfactant include sulfonic acid, carboxylic acid and phosphoric acid having a long-chain hydrocarbon group. Specific examples include dodecylsulfonic acid, eicosylsulfonic acid, decylbenzenesulfonic acid, sulfonic acids such as dodecylbenzenesulfonic acid and eicosylbenzenesulfonic acid, carboxylic acids such as dodecylcarboxylic acid, dodecylphosphoric acid, eicosylphosphoric acid, etc. In particular, the sulfonic acid compounds are preferred.

  The acidic group-containing surfactant can have an acidic group and a long-chain hydrocarbon group bonded via various inorganic groups or organic groups, but the acidic group and the long-chain hydrocarbon group are directly It is preferable that they are bonded. The reason for this is not clear, but it is a structure in which a long-chain hydrocarbon group that is a hydrophobic group and an acidic group that is a hydrophilic group are directly connected to each other, making it acidic to an aqueous medium (aqueous phase) in an aqueous medium. Water that is produced in the polycondensation reaction is realized by reliably realizing the state in which the groups are oriented and the hydrophobic groups are oriented to the oil droplets (oil phase) comprising the composition for forming the hybrid resin particles. Is estimated to be effectively discharged into the water phase.

  This acidic group-containing surfactant needs to be contained in an amount that gives a concentration equal to or lower than the critical micelle concentration in the aqueous medium. By containing the amount of the acidic group-containing surfactant in the aqueous medium at a concentration equal to or lower than the critical micelle concentration, oil droplets can be stably formed without forming micelles in the aqueous medium. In addition, since there is no excess surfactant, it is expected that all surfactants are properly oriented around the oil droplets when stable oil droplets are formed. It is presumed that the proper orientation state can reliably exert the function as a catalyst related to the dehydration of the polycondensation reaction in the polymerization step described in detail in (2) below, and can increase the reaction rate of the polycondensation reaction. Is done.

  Specifically, the acidic group-containing surfactant may be a critical micelle concentration or less in an aqueous medium, specifically 80% or less, more preferably 70% or less of the critical micelle concentration, but is limited. It is not something. The lower limit of the content of the acidic group-containing surfactant is only required to exert a catalyst action in the polycondensation reaction for obtaining the polyester resin. When this lower limit is included, the acidic group-containing surfactant is included. More specifically, the content of is 0.01 to 2 mass%, more preferably 0.1 to 1.5 mass% in the aqueous medium.

An appropriate anionic surfactant or nonionic surfactant may be contained in the aqueous medium in order to stabilize oil droplets made of the composite resin particle forming composition.
[Polycarboxylic acid]
The polycondensable monomer polyvalent carboxylic acid contained in the composite resin particle forming composition used in the toner production method according to the present invention is a divalent or higher carboxylic acid, for example, oxalic acid, Malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, n-dodecyl succinic acid, n-dodecenyl succinic acid, Dicarboxylic acids such as isododecyl succinic acid, isododecenyl succinic acid, n-octyl succinic acid, n-octenyl succinic acid; aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid; trimellitic acid, Examples include pyromellitic acid, trihydric or higher carboxylic acids such as acid anhydrides or acid chlorides. It is possible.

  The polyvalent carboxylic acid can be used alone or in combination of two or more.

  When trivalent or higher carboxylic acids are used as the polyvalent carboxylic acid, hybrid resin particles having a crosslinked structure can be obtained in the polymerization step.

The proportion of the trivalent or higher carboxylic acid is preferably 0.1% by mass to 10% by mass based on the whole polyvalent carboxylic acid.
[Polyhydric alcohol]
The polycondensable monomer polyhydric alcohol contained in the composite resin particle forming composition used in the toner production method according to the present invention is a dihydric or higher alcohol, such as ethylene glycol, diethylene glycol, Triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,4-butylenediol, neopentyl glycol, 1,5-pentane glycol, 1,6-hexane glycol, 1,7-heptane glycol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, pinacol, cyclopentane-1,2-diol, cyclohexane-1,4-diol, cyclohexane-1 , 2-diol, cyclohexane-1,4-dimethanol, dipro Diols such as lenglycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, bisphenol A, bisphenol Z, hydrogenated bisphenol A; glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, trisphenol PA, phenol novolac And trihydric or higher polyhydric aliphatic alcohols such as cresol novolac; and alkylene oxide adducts of the trihydric or higher polyhydric aliphatic alcohols.

  A polyhydric alcohol can be used 1 type or in combination of 2 or more types.

  When a trivalent or higher polyhydric aliphatic alcohol or an alkylene oxide adduct thereof is used as the polyhydric alcohol, hybrid resin particles having a crosslinked structure can be obtained in the polymerization step.

  The proportion of trihydric or higher polyhydric aliphatic alcohols or alkylene oxide adducts thereof used is preferably 0.1% by mass to 10% by mass with respect to the whole polyhydric alcohol.

  The ratio between the polyhydric alcohol and the polycarboxylic acid in the polycondensable monomer is the equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] of the polyhydric alcohol and the carboxyl group [COOH] of the polycarboxylic acid. However, it is preferably 1.5 / 1 to 1 / 1.5, more preferably 1.2 / 1 to 1 / 1.2.

  When the ratio between the polyhydric alcohol and the polyvalent carboxylic acid is in the above range, a polyester resin having a desired molecular weight can be obtained with certainty.

  The polycondensable monomer of the composite resin particle forming composition can contain a very small amount of a monovalent carboxylic acid and / or a monovalent alcohol together with a polyvalent carboxylic acid and a polyhydric alcohol. Such a monovalent carboxylic acid and a monovalent alcohol act as a polymerization terminator in the polycondensation reaction in oil droplets, and the molecular weight of the polyester resin obtained can be adjusted by the addition amount thereof.

In the method for producing a toner according to the present invention, the content of the polycondensable monomer is preferably 10 to 90% by mass, more preferably 20 to 80% by mass in the entire composition for forming hybrid resin particles. is there. If the content of the polycondensable monomer is too small, the resulting toner may not sufficiently exhibit viscoelasticity due to the polyester resin component, so that sufficient fixability cannot be obtained, and toner offset may occur. is there. Further, when the content of the polycondensable monomer is excessive, there is a risk that the low-temperature fixability by the styrene acrylic resin component described later is sufficiently exhibited in the obtained toner and the fixability is reduced. There is.
[Styrene compound]
Examples of the radical polymerizable monomer styrene compound contained in the composite resin particle forming composition used in the method for producing a toner according to the present invention include styrene, o-methylstyrene, m-methylstyrene, and p-methylstyrene. , Α-methylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-tert-butylstyrene, pn-hexylstyrene, p Examples include styrene monomers or styrene derivatives such as -n-octyl styrene, pn-nonyl styrene, pn-decyl styrene, and pn-dodecyl styrene, which are used alone or in combination of two or more. Can be used.

The content of the styrene compound is not particularly limited. From the viewpoint of adjusting the softening point temperature and the glass transition temperature of the styrene acrylic resin, it is generally preferably 40 to 95 in the whole radical polymerizable monomer. It is 50 mass%, More preferably, it is 50-80 mass%.
[Acrylic acid ester compound]
The acrylic acid ester compound of the radical polymerizable monomer contained in the composite resin particle forming composition used in the method for producing a toner according to the present invention includes (meth) acrylic acid esters in addition to acrylic acid esters. . Examples of the (meth) acrylic acid ester compound include methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, Methacrylic acid ester derivatives such as stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate; methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-acrylate -Acrylic acid ester such as butyl, isobutyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, phenyl acrylate, etc. Mentioned and Le derivatives, they may be used alone or in combination.

  The content of the acrylate compound is not particularly limited. In general, from the viewpoint of adjusting the softening point temperature and the glass transition temperature of the styrene acrylic resin, it is preferably 5 in the whole radical polymerizable monomer. -60 mass%, More preferably, it is 10-50 mass%.

  Further, the radical polymerizable monomer may contain a compound having an ionic dissociation group. Examples of the compound having an ionic dissociation group include a substituent such as a carboxyl group, a sulfonic acid group, and a phosphoric acid group as a constituent group of the monomer. Specifically, acrylic acid, methacrylic acid, Maleic acid, itaconic acid, cinnamic acid, fumaric acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester, styrene sulfonic acid, allyl sulfosuccinic acid, 2-acrylamido-2-methylpropane sulfonic acid, acid phosphooxyethyl And methacrylate and 3-chloro-2-acid phosphooxypropyl methacrylate.

  Furthermore, the radical polymerizable monomer may contain a polyfunctional vinyl compound. Examples of this polyfunctional vinyl compound include divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl. The compound which has 2 or more unsaturated bonds, such as glycol diacrylate, is mentioned, These can be used 1 type or in combination of 2 or more types. When the radical polymerizable monomer contains a polyfunctional vinyl compound, a styrene acrylic resin having a crosslinked structure can be obtained in the radical copolymerization step of the polymerization step.

  The content of the polyfunctional vinyl compound can be selected according to the elasticity required in the obtained styrene acrylic resin, and is generally 0.01 to 10% in the whole radical polymerizable monomer. It is preferable that it is mass%, More preferably, it is 0.02-5 mass%. When the content of the polyfunctional vinyl compound is excessive, the resulting styrene-acrylic resin has a high crosslinking rate and an excessively high softening point temperature. May be reduced. Moreover, when content of a polyfunctional vinyl compound is too small, a crosslinked structure part cannot fully be obtained and the effect by bridge | crosslinking cannot fully be exhibited.

  The composition for forming hybrid resin particles used in the method for producing a toner according to the present invention contains a polymerization initiator in order to generate radicals in oil droplets that initiate a radical copolymerization reaction in a polymerization step described later. It may be.

  As such a polymerization initiator, an oil-soluble polymerization initiator can be used, and as an oil-soluble polymerization initiator, for example, 2,2′-azobis- (2,4-dimethylvaleronitrile), 2 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyro Azo or diazo polymerization initiators such as nitrile, benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide, dicumyl peroxide 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, , 2-bis- (4,4-t-butylperoxycyclohexyl) propane, tris- (t-butylperoxy) triazine and other polymerization initiators and polymer initiators having a peroxide in the side chain Can be mentioned.

  In addition to containing an oil-soluble polymerization initiator in the oil droplets, a water-soluble polymerization initiator is contained in the aqueous medium to generate radicals in the oil droplets to start the radical copolymerization reaction and the aqueous system. It can also be set as the structure made to produce | generate in a medium and to supply to an oil droplet.

  Examples of the water-soluble polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate, azobisaminodipropane acetate, azobiscyanovaleric acid and salts thereof, and hydrogen peroxide.

  In addition, the oil droplets do not contain a polymerization initiator, only a water-soluble polymerization initiator is contained in the aqueous medium, and radicals that initiate radical copolymerization reaction are generated only in the aqueous medium and supplied to the oil droplets. It can also be set as the structure to make.

In the method for producing a toner according to the present invention, the content of the radical copolymerizable monomer is preferably 10 to 90% by mass, and more preferably 20 to 80% by mass in the entire composite resin particle forming composition. If the content of the radical copolymerizable monomer is too low, the low temperature fixability by the styrene acrylic resin component may not be sufficiently obtained, and the content of the radical copolymerizable monomer is excessive. In some cases, the viscoelasticity of the polyester resin component is not sufficiently exhibited and toner offset may occur.
〔Organic solvent〕
The composite resin particle forming composition used in the method for producing a toner according to the present invention may contain various oil-soluble components such as an organic solvent. Examples of such an organic solvent include those having a low boiling point and low solubility in water, such as toluene and ethyl acetate.

Further, the composite resin particle forming composition used in the method for producing a toner according to the present invention may contain a colorant or a wax. By carrying out the polymerization step using such a composition for forming mixed resin particles containing a colorant or wax, it is possible to obtain hybrid resin particles that are pre-colored or pre-containing wax. The content of the wax is 2 to 20% by mass, preferably 3 to 18% by mass, and more preferably 4 to 15% by mass in the entire composition for forming hybrid resin particles.
(2) polymerization step;
In the polymerization step, in the oil droplets dispersed in the aqueous medium in the oil droplet forming step, a polycondensation step in which a polyvalent carboxylic acid and a polyhydric alcohol are polycondensed to obtain a polyester resin, a styrene compound and (meta ) A radical copolymerization process in which an acrylic ester compound is radically copolymerized to obtain a styrene acrylic resin is performed to obtain hybrid resin particles in which a polyester resin and a styrene acrylic resin are mixed with high uniformity.
(2-1) polycondensation step;
In this polycondensation step, the acidic group-containing surfactant is oriented on the surface of the formed oil droplets with the hydrophilic group consisting of acidic groups in the aqueous phase and the hydrophobic group consisting of long-chain hydrocarbon groups oriented in the oil phase. The acidic groups present at the interface between the oil droplets and the aqueous phase exert the catalytic effect of dehydration, and the water generated in the polycondensation is removed from the oil droplets. It is estimated that the polycondensation reaction accompanied by dehydration proceeds in the existing oil droplets.

  The polymerization temperature for performing polycondensation is usually 40 ° C. or higher, preferably 50 to 150 ° C., although it depends on the type of polyvalent carboxylic acid and polyhydric alcohol contained in the composite resin particle forming composition. It is more preferable that it is 50-100 degreeC from the objective of setting it as the boiling point or less of water. Moreover, although superposition | polymerization reaction time is based also on the reaction rate of the polycondensation which forms a hybrid resin particle, it is 4 to 10 hours normally.

  The polyester resin obtained in the polycondensation step has a molecular weight measured by gel permeation chromatography (GPC) of 10,000 or more, preferably 20,000 to 10,000,000, more preferably in terms of weight average molecular weight (Mw). Is preferably 30,000 to 1,000,000. When the weight average molecular weight is less than 10,000, an offset phenomenon may occur at a high temperature in the fixing process of the image forming operation using the toner.

  Moreover, this polyester resin has a molecular weight measured by GPC of 20,000 or less, preferably 1,000 to 10,000, more preferably 2,000 to 8,000 in terms of number average molecular weight (Mn). When the number average molecular weight exceeds 20,000, the low-temperature fixability in the fixing process of image formation using the toner, and the desired glossiness cannot be obtained for an image obtained by image formation when a color toner is used. There is a fear.

The polyester resin preferably has a glass transition temperature of 20 to 90 ° C and a softening temperature of 80 to 220 ° C, a glass transition temperature of 35 to 65 ° C, and a softening temperature of 80 to 150 ° C. More preferably it is. The glass transition temperature is measured by the onset method at the time of the second temperature increase in the differential calorimetric analysis method, and the softening point temperature can be measured by the half method of the Koka type flow tester.
(2-2) radical copolymerization step;
In this radical copolymerization process, in the formed oil droplets, radicals are generated by the polymerization initiator contained in the oil droplets and / or radicals generated by the polymerization initiator contained in the aqueous medium. Is supplied to the oil droplets to initiate a radical copolymerization reaction.

  The polymerization temperature at which radical copolymerization is carried out depends on the type of styrene compound and (meth) acrylic acid ester compound contained in the composition for forming hybrid resin particles, and the type of polymerization initiator that generates radicals, but is usually 50. It is -100 degreeC, Preferably it is 55-90 degreeC, More preferably, it is 3-20 degreeC. Moreover, although superposition | polymerization reaction time is based also on the reaction rate of the radical copolymerization which synthesize | combines a styrene acrylic resin, it is 5 to 12 hours normally.

  The styrene acrylic resin obtained in the radical copolymerization step preferably has a molecular weight measured by gel permeation chromatography (GPC) of 2,000 to 1,000,000 in terms of weight average molecular weight (Mw). Is preferably 1,000 to 100,000 in terms of number average molecular weight (Mn). The molecular weight distribution (Mw / Mn) is preferably 1.5 to 100, particularly 1.8 to 70. When the weight average molecular weight (Mw), the number average molecular weight (Mn), and the molecular weight distribution (Mw / Mn) are in the above ranges, the occurrence of an offset phenomenon is suppressed in the fixing process of the image forming operation using the obtained toner. be able to.

  The styrene acrylic resin obtained in the radical copolymerization step preferably has a glass transition temperature of 30 to 70 ° C, and preferably has a softening temperature of 80 to 170 ° C. When the glass transition point temperature and softening point temperature are in the above ranges, good fixability can be obtained.

In the above polymerization step, for example, first, after performing a polycondensation reaction, a radical copolymerization reaction is started in the presence of a polyester resin.
(3) agglomeration step;
In the agglomeration step, a dispersion of mixed resin particles obtained by the polymerization step (2) above, and a dispersion of colorant particles and, if necessary, wax particles, charge control agent particles, and other toner component particles are used. A dispersion liquid for aggregation is prepared by mixing, and the mixed resin particles and the colorant particles are aggregated and fused in an aqueous medium to form a dispersion of toner particles.

  Specifically, a coagulant having a critical coagulation concentration or higher is added to the dispersion for coagulation and salted out, and at the same time, the agitation mechanism is agitated in a reaction apparatus (see FIG. 1) which is an agitating blade described later to constitute the hybrid resin particles. The polyester resin and the styrene-acrylic resin are heated and fused at a temperature higher than the glass transition temperature to gradually grow the particle size while forming agglomerated particles. The growth is stopped, and the particle surface is smoothed while heating and stirring to control the shape to form toner particles.

In addition, you may add the organic solvent which is infinitely soluble with respect to water simultaneously with a coagulant | flocculant to the dispersion liquid for aggregation here. Further, for example, an agglomeration aid composed of slaked lime, soda ash, bentonite, fly ash, kaolin and the like can be used.
〔wax〕
As the wax constituting the wax particles, for example, low molecular weight polyethylene wax, low molecular weight polypropylene wax, Fischer-Tropsch wax, microcrystalline wax, hydrocarbon wax such as paraffin wax, carnauba wax, pentaerythritol behenate, Examples thereof include ester waxes such as behenyl citrate, and these can be used alone or in combination of two or more.

  The content ratio of the wax is 2 to 20% by mass, preferably 3 to 18%, more preferably 4 to 15% by mass in the whole toner.

  Although it does not specifically limit as a flocculant, The thing selected from the salt of a metal is used suitably.

  Specifically, monovalent metal salts such as alkali metal salts such as sodium, potassium and lithium, for example, divalent metal salts such as calcium, magnesium, manganese and copper, and trivalent such as iron and aluminum Examples of specific salts include sodium chloride, potassium chloride, lithium chloride, calcium chloride, magnesium chloride, zinc chloride, copper sulfate, magnesium sulfate, and manganese sulfate. Of these, divalent metal salts are particularly preferred. When a divalent metal salt is used, agglomeration can be promoted with a smaller amount. These may be used alone or in combination of two or more.

  The addition amount of the flocculant to the dispersion for aggregation needs to be not less than the critical aggregation concentration, preferably 1.2 times or more, more preferably 1.5 times or more the critical aggregation concentration.

  Here, the “critical flocculation concentration” is an index relating to the stability of the aqueous dispersion, and indicates a concentration at which flocculation occurs when a flocculant is added. This critical agglomeration concentration varies greatly depending on the dispersed particle components and the like. For example, a detailed critical aggregation concentration can be obtained by a technique described in Seizo Okamura et al., “Polymer Chemistry 17,601 (1960) edited by Japan Society of Polymer Science”. Another method is to add the desired salt to the target flocculation dispersion at a different concentration, measure the ξ (zeta) potential of the flocculation dispersion, and determine the critical salt concentration at which this value changes. It can also be determined as the aggregation concentration.

  As the organic solvent that is infinitely soluble in water, a solvent that does not dissolve the formed polyester resin is selected. Specifically, methanol, ethanol, 1-propanol, 2-propanol, ethylene glycol, glycerin, acetone, and the like are used. Examples thereof include methanol, ethanol, 1-propanol and 2-propanol alcohol having 3 or less carbon atoms, and 2-propanol is particularly preferable.

  The addition amount of the organic solvent that is infinitely soluble in water is preferably 1 to 100% by volume with respect to the flocculation dispersion liquid to which a flocculant is added.

  In the flocculation step, it is preferable that the standing time (time until heating is started) to be left after adding the flocculant is as short as possible. That is, after adding the flocculant, it is preferable to start heating the flocculation dispersion as quickly as possible so that the temperature is equal to or higher than the glass transition temperature of the hybrid resin particles. The reason for this is not clear, but the agglomeration state of the particles fluctuates with the passage of the standing time, resulting in problems that the particle size distribution of the obtained toner particles becomes unstable and the surface property fluctuates. is there. The standing time is usually within 30 minutes, preferably within 10 minutes. The temperature at which the flocculant is added is not particularly limited, but is preferably equal to or lower than the glass transition temperature of the polyester resin and styrene acrylic resin constituting the hybrid resin particles.

Further, in the aggregation process, it is necessary to quickly raise the temperature by heating, and the temperature raising rate is preferably 1 ° C./min or more. The upper limit of the heating rate is not particularly limited, but is preferably 15 ° C./min or less from the viewpoint of suppressing the generation of coarse particles due to rapid progress of fusion. Furthermore, it is important to continue the fusion by holding the temperature of the aggregation dispersion liquid for a certain period of time after the aggregation dispersion liquid reaches a temperature equal to or higher than the glass transition temperature. As a result, toner particle growth (aggregation of hybrid resin particles and colorant particles) and fusion (disappearance of the interface between the particles) can be effectively advanced, and the durability of the finally obtained toner particles can be improved. Can be improved.
[Colorant]
A dispersion of colorant particles can be prepared by dispersing a colorant in an aqueous medium. The dispersion treatment of the colorant is performed in a state where the surfactant concentration is higher than the critical micelle concentration in the aqueous medium. Although the disperser used for the dispersion | distribution process of a coloring agent is not specifically limited, What was used in the oil droplet formation process of said (1) can be mentioned. Moreover, it is although it does not specifically limit as surfactant which can be used, The following anionic surfactant can be mentioned as an example of a suitable thing.

  Examples of the anionic surfactant include sodium dodecyl sulfonate, sodium dodecyl benzene sulfonate, sodium arylalkyl polyether sulfonate, 3,3-disulfone diphenylurea-4,4-diazo-bis-amino-8-naphthol- Sulfonates such as sodium 6-sulfonate, 2,2,5,5-tetramethyl-triphenylmethane-4,4-diazo-bis-β-naphthol-6-sodium sulfonate; sodium dodecyl sulfate, tetradecyl sulfate Sulfates such as sodium, sodium pentadecyl sulfate, sodium octyl sulfate; sodium oleate, sodium laurate, sodium caprate, sodium caprylate, sodium caproate, potassium stearate, calcium oleate Fatty acid salts, such as arm, and the like.

  As the colorant to be used, carbon black, magnetic substance, dye, pigment, etc. can be arbitrarily used, and as channel black, furnace black, acetylene black, thermal black, lamp black, etc. are used as carbon black. . Magnetic materials include ferromagnetic metals such as iron, nickel and cobalt, alloys containing these metals, compounds of ferromagnetic metals such as ferrite and magnetite, alloys that do not contain ferromagnetic metals but exhibit ferromagnetism by heat treatment, For example, a kind of alloy called Heusler alloy such as manganese-copper-aluminum and manganese-copper-tin, chromium dioxide, and the like can be used.

  As the dye, C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 122, C.I. I. Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162, C.I. I. Solvent Blue 25, 36, 60, 70, 93, 95, etc. can be used, and mixtures thereof can also be used. Examples of the pigment include C.I. I. Pigment Red 5, 48: 1, 53: 1, 57: 1, 122, 139, 144, 149, 166, 177, 178, 222, C.I. I. Pigment Orange 31 and 43, C.I. I. Pigment Yellow 14, 17, 74, 93, 94, 138, 155, 180, 185, C.I. I. Pigment green 7, C.I. I. Pigment Blue 15: 3, 60, etc. can be used, and a mixture thereof can also be used. The number average primary particle diameter varies depending on the type, but is preferably about 10 to 200 nm.

  As the charge control agent constituting the charge control agent particles, various known ones that can be dispersed in an aqueous medium can be used. Specific examples include nigrosine dyes, naphthenic acid or higher fatty acid metal salts, alkoxylated amines, quaternary ammonium salt compounds, azo metal complexes, salicylic acid metal salts or metal complexes thereof.

The charge control agent particles preferably have a number average primary particle diameter of about 10 to 500 nm in a dispersed state.
[Reactor]
In the toner composed of toner particles obtained by agglomerating and fusing the hybrid resin particles, the flow in the reactor is made into a laminar flow and a stirring blade and a stirring tank that can make the internal temperature distribution uniform are used. Then, by controlling the temperature, the number of rotations, and the time in the aggregation step, the desired shape factor and highly uniform shape distribution can be obtained. The reason why a toner having a highly uniform shape distribution can be obtained is that when an agglomeration step is performed in a place where a laminar flow is formed, strong stress is not applied to the agglomerated particles in which aggregation and fusion progress, and In the laminar flow in which the flow is accelerated, it is presumed that the shape distribution of the aggregated particles becomes uniform as a result of the uniform temperature distribution in the stirring tank. Furthermore, by performing a shape control step by heating and stirring, the aggregated particles gradually become spherical, and the shape of the resulting toner particles can be arbitrarily controlled.

  As a stirring blade and a stirring tank used when manufacturing a toner composed of toner particles obtained by aggregating and fusing the hybrid resin particles, for example, the one shown in FIG. it can.

  This reactor is equipped with a multistage stirrer blade in which an upper stirrer blade is disposed with a crossing angle α preceding the lower stirrer blade in the rotational direction. It has a feature that an obstacle such as a baffle that forms a flow is not provided.

  FIG. 1 is a perspective view showing an example of a reaction apparatus.

  In the reaction apparatus shown in FIG. 1, a rotating shaft 3 is vertically suspended from a central portion of a vertical cylindrical stirring tank 2 having a heat exchange jacket 1 attached to the outer periphery thereof. The stirring blade 4b located in the lower stage close | similar to the bottom face of this and the stirring blade 4a located in the upper stage are provided. The upper stirring blade 4a has a crossing angle α preceding the stirring blade 4b positioned in the lower stage in the rotational direction.

  In FIG. 1, the arrows indicate the direction of rotation, 7 is an upper material inlet, and 8 is a lower material inlet.

  In the toner manufacturing method according to the present invention, the crossing angle α of the stirring blades 4a and 4b is preferably less than 90 °. The lower limit of the crossing angle α is not particularly limited, but is preferably 5 ° or more and less than 90 °, more preferably 10 ° or more and less than 90 °.

  By setting it as such a structure, the dispersion liquid for aggregation is first stirred by the stirring blade 4a arrange | positioned at the upper stage, and the flow to the lower side is formed. Next, the flow formed by the upper stirring blade 4a is further accelerated downward by the stirring blade 4b disposed in the lower stage, and a downward flow is separately formed in the stirring blade 4a itself, and the flow as a whole is increased. Presumed to be accelerated and proceed.

  The shape of the stirring blade is not particularly limited as long as it does not form a turbulent flow, but is formed from a continuous plate having no through-hole or the like, such as the rectangular plate shown in FIG. Those are preferable, and may have a curved surface.

Since the stirring blade does not form a turbulent flow, coalescence of the hybrid resin particles does not occur in the polymerization process, and further, redispersion due to the destruction of the hybrid resin particles does not occur. Further, in the aggregation process, excessive collision between the aggregated particles can be suppressed, and the uniformity of the particle size distribution can be improved. Therefore, a toner having a uniform particle size distribution can be obtained. Furthermore, since excessive coalescence of particles can be suppressed, a toner having a uniform shape can be obtained.
(4) Filtration and washing process;
In this filtration / washing step, a filtration treatment for filtering the toner particles from the dispersion of toner particles obtained in the above aggregation step, and a surfactant or a surfactant from the filtered toner particles (cake-like aggregate) A cleaning process for removing deposits such as an aggregating agent is performed. Here, examples of the filtration method include a centrifugal separation method, a vacuum filtration method using Nutsche and the like, a filtration method using a filter press and the like, and are not particularly limited.
(5) drying step;
In this drying process, the toner particles that have been subjected to the cleaning process are subjected to a drying process. Examples of the dryer used in the drying step include a spray dryer, a vacuum freeze dryer, and a vacuum dryer. The water content of the dried toner particles is preferably 1.0% by mass or less, and more preferably 0.5% by mass or less.

  Here, the water content of the toner particles can be measured by the Karl Fischer method. Specifically, using a moisture content measuring apparatus “AQS-724” (manufactured by Hiranuma Sangyo Co., Ltd.) under the conditions of a sample humidity adjustment environment condition of a temperature of 30 ° C., a humidity of 85% RH, and a sample heating condition of 110 ° C., a temperature of 30 ° C. The amount of water measured in the toner particles left for 24 hours in a high-temperature and high-humidity environment with a humidity of 85% RH was defined as the amount of water in the toner particles.

Further, when the dried toner particles are aggregated by weak interparticle attractive force to form an aggregate, the aggregate may be crushed. Here, as the crushing treatment apparatus, a mechanical crushing apparatus such as a jet mill, a Henschel mixer, a coffee mill, or a food processor can be used.
(6) External additive addition step;
This external additive adding step is a step of adding an external additive to the dried toner particles for the purpose of improving fluidity, chargeability and cleaning properties. Examples of the apparatus used for adding the external additive include various known mixing apparatuses such as a Turbuler mixer, a Henschel mixer, a Nauter mixer, and a V-type mixer.

  The external additive is not particularly limited, and various inorganic fine particles, organic fine particles, lubricants and the like can be used. As the inorganic fine particles, inorganic oxide particles such as silica, titania, and alumina are preferably used, and these inorganic fine particles are preferably hydrophobized with a silane coupling agent or a titanium coupling agent.

  The degree of the hydrophobizing treatment is not particularly limited, but a methanol wettability of 40 to 95 is preferable. Methanol wettability is an evaluation of wettability to methanol. In this method, 0.2 g of inorganic fine particles to be measured is weighed and added to 50 ml of distilled water in a 200 ml beaker. Methanol is slowly added dropwise from a burette, the tip of which is immersed in a liquid, with slow stirring until the entire inorganic fine particles are wet. When the amount of methanol necessary to completely wet the inorganic fine particles is a (ml), the degree of hydrophobicity is calculated by the following formula 1.

(Formula 1) Degree of hydrophobicity = {a / (a + 50)} × 100
The amount of the external additive added is 0.1 to 5.0% by mass in the toner, preferably 0.5 to 4.0% by mass. In addition, various external additives may be used in combination.
[Particle size of toner particles]
Further, in the toner obtained by the above production method, it is preferable that the particle diameter of the toner particles is 3 to 8 μm in terms of volume-based median diameter (D ₅₀ ). The particle size of the toner particles can be controlled by the concentration of the aggregating agent, the amount of the organic solvent added in the aggregating step, the fusing time, and the composition of the polyester resin. Since the median diameter (D ₅₀ ) on the volume basis is 3 to 8 μm, toner particles having high adhesion force that fly and adhere to the heating member and generate toner offset in the fixing process are reduced, and transfer efficiency is improved. It becomes higher and the image quality of halftone improves, and the image quality of fine lines and dots improves.

The median diameter (D ₅₀ ) on the volume basis is measured by the following measuring method.

The volume-based median diameter (D ₅₀ ) of the toner can be measured and calculated using a device in which a computer system (manufactured by Beckman Coulter) for data processing is connected to Coulter Multisizer 3 (manufactured by Beckman Coulter). it can.

  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 pipetted into a beaker containing ISOTON II (manufactured by Beckman Coulter, Inc.) in a sample stand until the display density of the measuring instrument becomes 5 to 10%. By setting this concentration range, a reproducible measurement value can be obtained. In the measuring machine, the measurement particle count is 25000, the aperture diameter is 50 μm, and the frequency value is calculated by dividing the measurement range of 1 to 30 μm into 256 parts. The particle diameter of 50% from the larger volume integrated fraction is defined as the volume-based median diameter.

(Developer)
For example, when the toner according to the present invention is used as a one-component magnetic toner containing a magnetic substance, or when used as a two-component developer by mixing with a so-called carrier, a non-magnetic toner can be used alone. Any of the toners according to the present invention can be suitably used. However, in the present invention, it is preferable to use the toner as a two-component developer used by mixing with a carrier that is easy to obtain a high-quality print image.

  As the carrier constituting the two-component developer, magnetic particles made of conventionally known materials such as metals such as iron, ferrite, and magnetite, and alloys of these metals with metals such as aluminum and lead can be used. It is particularly preferable to use ferrite particles.

The median diameter (D ₅₀ ) based on the volume of the carrier is preferably 15 to 100 μm, and more preferably 25 to 60 μm. The measurement of the median diameter (D ₅₀ ) based on the volume of the carrier can be measured by a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by SYMPATEC) equipped with a wet disperser.

  As the carrier, it is preferable to use a carrier 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. In addition, the resin for constituting the resin-dispersed carrier is not particularly limited, and a known resin can be used. For example, a styrene acrylic resin, a polyester resin, a fluorine resin, a phenol resin, or the like can be used. Can do.

(Contact heating fixing device)
A contact heating type fixing device used in the image forming method of the present invention will be described.

  The contact heating fixing device comprises a belt-like heating means and a belt-like pressurizing means, and a nip portion is formed by a contact portion between the belt-like heating means heated by a heat source and the belt-like pressurizing means. This is a device for fixing toner onto a transfer material at a nip portion.

  The structure of the contact heating type fixing device is not particularly limited as long as the belt-shaped heating unit and the belt-shaped pressurizing unit are in contact with each other and the contact portion has a certain nip width.

  FIG. 2 is a schematic diagram showing an example of a contact heating type fixing device having a belt-shaped heating unit and a belt-shaped pressing unit.

  In FIG. 2, 1 is a contact heating fixing device, 2 is a belt-like heating means, 3 is a belt-like pressurizing means, 4 is a heat source, 5 is a tension roll, 6 is a pressure contact member having a heat source, 7 is a drive roll, Reference numeral 8 denotes a pressure contact member, and N denotes a nip portion.

  FIG. 2A shows a structure in which the belt-like heating means 2 is pressed against the belt-like pressurizing means 3 by the tension roll 5, and the belt-like heating means is connected to the heat source 4 built in the tension roll 5. 2 has a structure to be heated. The width of the nip portion is set by the structure.

  FIG. 2B shows a structure in which the belt-like heating means 2 is pressed against the belt-like pressurizing means 3 by the tension roll 5, and the belt-like heating means 2 is heated by the pressure-contacting member 6 having a heat source. It is of the structure that is made.

  Next, the belt-like heating means and the belt-like pressurizing means will be described.

  As the shape of the belt-shaped heating means, a seamless heating belt is preferable.

  As the heating belt, a belt having heat resistance and flexibility and having releasability from the melted toner is used.

  Specifically, a three-layer structure of an elastic layer silicone rubber and a surface layer PFA (perfluoroalkoxy) tube on a base polyimide, a base polyester, a polyperfluoroalkyl vinyl ether, a polyimide or a polyetherimide and a fluororesin And a heating belt having a two-layer structure in which a release material layer to which a conductive material is added is coated.

  A seamless pressure belt is suitable as the shape of the belt-shaped pressure means.

  As the pressure belt, a pressure belt that is heated by the heating belt and has heat resistance and transports the support satisfactorily is suitable.

  Specifically, a pressure belt in which an elastic layer silicone rubber is provided on a base polyimide is preferable.

  FIG. 3 is a schematic view showing an example of a contact heating fixing device including a heating belt and a pressure belt used in the present invention.

  In FIG. 3, 24 is a fixing device, 241 is a heating belt, 242 is a pressure belt, 243 is a roller, 244 is a roller, 245a and 245b are tension rollers, 246a and 246b are tension rollers, HL1 is a heat source, AS1 and AS2 are The pressure contact member is shown.

  The heating belt 241 is stretched by a roller 243 incorporating a heat source HL1 and tension rollers 245a and 245b, and the pressure belt 242 is stretched by a roller 244 and tension rollers 246a and 246b.

  The pressure contact member AS1 includes an elastic member DB1 and a support member SB1 that supports the elastic member DB1, and the pressure contact member AS2 includes an elastic member DB2 and a support member SB2 that supports the elastic member DB2. As the elastic members DB1 and DB2, silicone rubber having heat insulating properties is preferably used. A metal plate or a heat resistant resin is preferably used for the support members SB1 and SB2.

  The tension roller 245a contacts the tension roller 246a with the heating belt 241 and the pressure belt 242 interposed therebetween, and the tension roller 245b contacts the tension roller 246b with the heating belt 241 and pressure belt 242 interposed therebetween. By the contact between the tension rollers 245a and 245b and the tension rollers 246a and 246b, the heating belt 241 and the pressure belt 242 are contacted to form a nip portion N.

  In the present embodiment, the pressure contact member AS1 and the pressure contact member AS2 are normally disposed at positions separated from each other, and are not illustrated in accordance with the entrance of the transfer material P to which the toner image has been transferred into the nip portion N. It is pressed by known cam means (not shown) or the like according to instructions from the control means. However, it is also possible to form a low friction layer on the surface of the pressure contact member so that the pressure contact member is always in pressure contact with the heating belt 241 and the pressure belt 242.

  The elastic member DB1 of the pressure contact member AS1 is in pressure contact with the elastic member DB2 of the pressure contact member AS2 across the heating belt 241 and the pressure belt 242 at the nip portion N.

  When the transfer material P having the toner image transferred to the surface approaches the fixing device 24, the roller 243 is heated to a predetermined temperature by the heat source HL1, and the heating belt 241 is heated. When the transfer material P enters the nip portion N between the heating belt 241 and the pressure belt, heat is transmitted from the heated heating belt 241 and pressure contact portions AS1 and AS2 having elastic members DB1 and DB2 ( The transfer material P is heat-fixed by passing through (without reference sign).

  The nip width is 10 to 55 mm, preferably 15 to 40 mm. If the nip is narrow, heat cannot be uniformly applied to the toner, and uneven fixing occurs. On the other hand, when the nip width is wide, the melting of the resin is promoted, and the problem of excessive fixing offset occurs.

  The heating belt may be used with a fixing cleaning mechanism. As this method, a method of supplying silicone oil to a fixing upper roll or film, or a method of cleaning with a pad, roll, web or the like impregnated with silicone oil can be used.

(Image forming device)
Next, the image forming apparatus will be described.

  The image forming apparatus used in the present invention includes at least a charging unit that charges the surface of a photoconductor, an exposure unit that exposes the charged photoconductor to form an electrostatic latent image, and an electrostatic latent image on the photoconductor as a toner. Developing means for forming a toner image by developing the toner image, primary transfer means for transferring the toner image on the photoreceptor onto the intermediate transfer member, transfer means for transferring the toner image transferred onto the intermediate transfer member to a transfer material, Those having means for thermally fixing the toner on the transfer material to the transfer material using a contact heat fixing device comprising a heating belt and a pressure belt are preferable.

  In addition to the above-described units, the image forming apparatus preferably includes a cleaning unit for cleaning the intermediate transfer member and a unit for applying a lubricant to the surface of the photoreceptor.

  FIG. 4 is a cross-sectional configuration diagram illustrating an example of an image forming apparatus used in the present invention.

  This image forming apparatus is called a tandem color image forming apparatus, and includes a plurality of sets of image forming units 10Y, 10M, 10C, and 10K, an endless belt-shaped intermediate transfer body unit 7 as a transfer unit, and a transfer material P. An endless belt-like sheet feeding and conveying means 21 and a contact heating and fixing device 24 composed of a heating belt and a pressure belt as fixing means. A document image reading device SC is disposed on the upper part of the main body A of the image forming apparatus.

  As one of the different color toner images formed on each photoconductor, the image forming unit 10Y that forms a yellow image has a drum-shaped photoconductor 1Y as a first image carrier, and the photoconductor 1Y. A charging unit 2Y, an exposure unit 3Y, a developing unit 4Y, a primary transfer roller 5Y as a primary transfer unit, and a cleaning unit 6Y are arranged around the periphery. In addition, an image forming unit 10M that forms a magenta image as another different color toner image is arranged around a drum-shaped photoconductor 1M as a first image carrier, and around the photoconductor 1M. The charging unit 2M, the exposure unit 3M, the developing unit 4M, the primary transfer roller 5M as the primary transfer unit, and the cleaning unit 6M are included. In addition, an image forming unit 10C that forms a cyan image as one of other different color toner images includes a drum-shaped photoconductor 1C as a first image carrier, and around the photoconductor 1C. A charging unit 2C, an exposure unit 3C, a developing unit 4C, a primary transfer roller 5C as a primary transfer unit, and a cleaning unit 6C are disposed. An image forming unit 10K that forms a black image as one of other different color toner images is disposed around a drum-shaped photoconductor 1K as a first image carrier and the photoconductor 1K. A charging unit 2K, an exposure unit 3K, a developing unit 4K, a primary transfer roller 5K as a primary transfer unit, and a cleaning unit 6K.

  The endless belt-like intermediate transfer body unit 7 includes an endless belt-like intermediate transfer body 70 as a second image carrier having a semiconductive endless belt shape that is wound around a plurality of rollers and is rotatably supported.

  Each color image formed by the image forming units 10Y, 10M, 10C, and 10K is sequentially transferred and synthesized on the rotating endless belt-shaped intermediate transfer body 70 by the primary transfer rollers 5Y, 5M, 5C, and 5K. A color image is formed. A transfer material P such as a sheet as a transfer material accommodated in the paper feed cassette 20 is fed by a paper feed / conveying means 21, passes through a plurality of intermediate rollers 22 A, 22 B, 22 C, 22 D, and a registration roller 23, and is then secondary A color image is transferred onto the transfer material P at a time by being conveyed to a secondary transfer roller 5A as a transfer means. The transfer material P onto which the color image has been transferred is fixed by a contact heat fixing device 24 composed of a heating belt and a pressure belt, and is sandwiched between discharge rollers 25 and placed on a discharge tray 26 outside the apparatus. Is done.

  On the other hand, after the color image is transferred to the transfer material P by the secondary transfer roller 5A, the residual toner is removed from the endless belt-shaped intermediate transfer body 70 from which the transfer material P is separated by the curvature by the cleaning means 6A.

  During the image forming process, the primary transfer roller 5K is always in pressure contact with the photoreceptor 1K. The other primary transfer rollers 5Y, 5M, and 5C are in pressure contact with the corresponding photoreceptors 1Y, 1M, and 1C, respectively, only during color image formation.

  The secondary transfer roller 5A is in pressure contact with the endless belt-shaped intermediate transfer body 70 only when the transfer material P passes through the secondary transfer roller 5A.

  Further, the housing 8 can be pulled out from the apparatus main body A through the support rails 82L and 82R.

  The housing 8 includes image forming units 10Y, 10M, 10C, and 10K, and an endless belt-shaped intermediate transfer body unit 7.

  The image forming units 10Y, 10M, 10C, and 10K are arranged in tandem in the vertical direction. An endless belt-shaped intermediate transfer body unit 7 is disposed on the left side of the photoreceptors 1Y, 1M, 1C, and 1K in the figure. The endless belt-shaped intermediate transfer body unit 7 includes an endless belt-shaped intermediate transfer body 70 that can be rotated by winding rollers 71, 72, 73, and 76, primary transfer rollers 5Y, 5M, 5C, and 5K, and a cleaning unit 6A. Become.

  The image forming units 10Y, 10M, 10C, and 10K and the endless belt-shaped intermediate transfer body unit 7 are integrally pulled out from the main body A by the drawer operation of the housing 8.

  In this manner, toner images are formed on the photoreceptors 1Y, 1M, 1C, and 1K by charging, exposure, and development, and the toner images of the respective colors are superimposed on the endless belt-shaped intermediate transfer body 70, and are collectively applied to the transfer material P. The image is transferred, fixed and fixed by pressure and heating by a contact heat fixing device 24 composed of a heating belt and a pressure belt. The photoconductors 1Y, 1M, 1C, and 1K after transferring the toner image to the transfer material P are cleaned by the cleaning means 6A after the toner remaining on the photoconductor is transferred, and then the above charging, exposure, and development cycle. The next image formation is performed.

The process speed of this image forming apparatus is 220 mm / s when A4 size is used, and the primary transfer roller is a sponge roller having a resistance value of 1 × 10 ⁷ Ω and a diameter of 20 mm.

  The present invention will be specifically described below with reference to examples, but the embodiments of the present invention are not limited to these examples.

"toner"
A toner was prepared by the following method.

<Preparation of hybrid resin particles (1)>
Azelaic acid 32 g (139 mmol), 1,10-decanediol 28 g (139 mmol), styrene 80 g and butyl acrylate 20 g were heated to 95 ° C. and added to 240 g water containing 2 g dodecylbenzenesulfonic acid, Oil droplets were formed by dispersing with a sonic disperser, and then this reaction solution was reacted at 95 ° C. for 24 hours to obtain a polyester resin. At that time, as a result of measuring the molecular weight of the polyester resin portion, the weight average molecular weight (Mw) measured by GPC is 20,000, the number average molecular weight (Mn) is 10,000, the glass transition temperature Tg is 60 ° C., The softening point temperature was 125 ° C. Thereafter, the temperature is lowered to 80 ° C., an aqueous solution containing 1.5 g of potassium persulfate is added, radicals are supplied from the aqueous medium and reacted for 5 hours to obtain a styrene acrylic resin, and hybrid resin particles (1) Was prepared.

  In addition, as a result of measuring the molecular weight of the styrene acrylic resin portion separated from the hybrid resin particles, the weight average molecular weight (Mw) measured by GPC was 52,000, the number average molecular weight (Mn) was 9,000, and the molecular weight distribution. (Mw / Mn) was 5.7, glass transition temperature Tg was 53 ° C., and softening point temperature was 118 ° C. The size of the hybrid resin particles (1) was 210 nm in terms of number average primary particle size.

<Preparation of hybrid resin particles (2)>
22 g (54 mmol) of polyoxyethylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, 1.2 g (10 mmol) of neopentyl glycol, 10 g of terephthalic acid and 0.6 g of isophthalic acid (64 mmol in total) , 80 g of styrene and 20 g of 2-ethylhexyl acrylate, heated to 95 ° C., are added to 240 g of water containing 3 g of dodecylbenzenesulfonic acid, and dispersed with an ultrasonic disperser to form oil droplets. This reaction solution was reacted at 98 ° C. for 36 hours to obtain a polyester resin, and then the temperature was lowered to 80 ° C. and an aqueous solution containing 1.5 g of potassium persulfate was added. At that time, as a result of measuring the molecular weight of the polyester resin portion, the weight average molecular weight (Mw) measured by GPC is 30,000, the number average molecular weight (Mn) is 9,000, the glass transition temperature Tg is 52 ° C., The softening point temperature was 117 ° C. Thereafter, radicals were supplied from the aqueous medium and reacted for 5 hours to obtain a styrene acrylic resin to prepare hybrid resin particles (2).

  In addition, as a result of measuring the molecular weight of the styrene acrylic resin portion separated from the hybrid resin particles, the weight average molecular weight (Mw) measured by GPC was 53,000, the number average molecular weight (Mn) was 8,500, and the molecular weight distribution. (Mw / Mn) was 6.2, glass transition temperature Tg was 51 ° C., and softening point temperature was 114 ° C. The size of the hybrid resin particles (2) was 230 nm in terms of number average primary particle size.

<Preparation Example 3 of Hybrid Resin Particle>
Polyoxyethylene (2,2) -2,2-bis (4-hydroxyphenyl) propane 22 g (54 mmol), neopentyl glycol 1.2 g (10 mmol), terephthalic acid 9.5 g and isophthalic acid 0.5 g 60 mmol), 0.5 g (2 mmol) of trimellitic acid, 80 g of styrene and 20 g of butyl acrylate were heated to 95 ° C. and added to 240 g of water containing 3 g of dodecylbenzenesulfonic acid, Oil droplets were formed by dispersion, and then the reaction solution was reacted at 95 ° C. for 24 hours to obtain a polyester resin. At that time, as a result of measuring the molecular weight of the polyester resin portion, the weight average molecular weight (Mw) measured by GPC is 50,000, the number average molecular weight (Mn) is 5,000, the glass transition temperature Tg is 56 ° C., The softening point temperature was 120 ° C. Thereafter, the temperature is lowered to 80 ° C., an aqueous solution containing 1.5 g of potassium persulfate is added, radicals are supplied from the aqueous medium and reacted for 5 hours to obtain a styrene acrylic resin, and the hybrid resin particles (3) Was prepared.

  In addition, as a result of measuring the molecular weight of the styrene acrylic resin portion separated from the hybrid resin particles, the weight average molecular weight (Mw) measured by GPC was 53,000, the number average molecular weight (Mn) was 8,500, and the molecular weight distribution. (Mw / Mn) was 6.2, glass transition temperature Tg was 52 ° C., and softening point temperature was 117 ° C. The size of the hybrid resin particles (3) was 210 nm in terms of number average primary particle size.

<Preparation of colorant dispersion (1)>
1.0 g of anionic surfactant sodium dodecylbenzenesulfonate was dissolved in 30 ml of ion-exchanged water with stirring. While stirring this solution, 7 g of carbon black “Regal 330R” (manufactured by Cabot) was gradually added as a colorant, and then a mechanical disperser “Claremix” (manufactured by M Technique Co., Ltd.) was used. A dispersion of colorant particles (hereinafter also referred to as “colorant dispersion”) (1) was prepared by dispersion treatment. The particle diameter of the colorant particles in the obtained colorant dispersion (1) was measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.). there were.

<Preparation of colorant dispersion (2)>
In the preparation of the colorant dispersion liquid (1), a colorant dispersion liquid was prepared in the same manner as in Preparation Example 1 of the colorant dispersion liquid except that 8 g of the pigment “CI Pigment Yellow 185” was used instead of 7 g of carbon black. (2) was prepared. When the particle diameter of the colorant particles in the obtained colorant dispersion (2) was measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.), the mass average particle diameter was 87 nm. there were.

<Preparation of colorant dispersion (3)>
In the preparation of the colorant dispersion (1), coloring was performed in the same manner as in Preparation Example 1 of the colorant dispersion except that 8 g of quinacridone-based magenta pigment “CI Pigment Red 122” was used instead of 7 g of carbon black. An agent dispersion (3) was prepared. The particle diameter of the colorant particles in the obtained colorant dispersion (3) was measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.). there were.

<Preparation of colorant dispersion (4)>
In the preparation of the colorant dispersion liquid (1), the same procedure as in Preparation Example 1 of the colorant dispersion liquid was performed except that 7 g of the phthalocyanine cyan pigment “CI Pigment Blue 15: 3” was used instead of 7 g of carbon black. Thus, a colorant dispersion (4) was prepared. The particle diameter of the colorant particles in the obtained colorant dispersion (4) was measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.). there were.

<Preparation of wax dispersion (1)>
1.0 g of anionic surfactant sodium dodecylbenzenesulfonate was dissolved in 30 ml of ion-exchanged water with stirring. While heating this solution to 90 ° C. and stirring, 7 g of carnauba wax (refined carnauba wax No. 1) as a wax was dissolved by heating to 90 ° C., and then a mechanical disperser was added. Dispersion treatment was carried out at 90 ° C. for 7 hours using “CLEAMIX” (manufactured by M Technique Co., Ltd.), then cooled to 30 ° C., and a wax dispersion (hereinafter referred to as “wax dispersion”) (1) ) Was prepared. When the particle size of the wax in the obtained wax dispersion liquid (1) was measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.), the mass average particle size was 95 nm.

<Preparation of wax dispersion (2)>
1.0 g of anionic surfactant sodium dodecylbenzenesulfonate was dissolved in 30 ml of ion-exchanged water with stirring. This solution was heated to 90 ° C., and while stirring, 7 g of pentaerythritol behenate ester dissolved as a wax was heated to 90 ° C. and dissolved. Then, a mechanical disperser “CLEARMIX” (M・ Technique Co., Ltd. was used for dispersion treatment at 90 ° C. for 7 hours and then cooled to 30 ° C. to prepare a wax dispersion liquid (2). When the particle size of the wax in the obtained wax dispersion liquid (2) was measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.), the mass average particle size was 96 nm.

<Preparation of wax dispersion (3)>
1.0 g of anionic surfactant sodium dodecylbenzenesulfonate was dissolved in 30 ml of ion-exchanged water with stirring. This solution is heated to 90 ° C., and while stirring, 7 g of Fischer-Tropsch wax heated to 90 ° C. and dissolved as a wax is gradually added. Then, a mechanical disperser “Clearmix” (M Technique) For 7 hours at 90 ° C. and then cooled to 30 ° C. to prepare a wax dispersion (3). When the particle size of the wax in the obtained wax dispersion (3) was measured using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.), the mass average particle size was 91 nm.

<Manufacture of colored particles (K1)>
In a reaction vessel (four-necked flask) equipped with a temperature sensor, a cooling pipe, a nitrogen introducing device, and a stirring device, mixed resin particles (1), 30 parts by mass of ion-exchanged water, colorant dispersion (1) and wax After the dispersion (1) was charged and the internal temperature was adjusted to 30 ° C., a 5N sodium hydroxide aqueous solution was added to the aggregation dispersion to adjust the pH to 10.0. Next, an aqueous solution in which 1 part by mass of magnesium chloride hexahydrate was dissolved in 20 ml of ion-exchanged water was added over 10 minutes at 30 ° C. with stirring. After standing for 1 minute, the temperature increase was started, and the temperature of this association system was increased to 90 ° C. over 10 minutes. Stirring as shown in FIG. 1 was used for stirring.

In this state, the particle size of the aggregated particles was measured with FPIA2000, and when the median diameter (D ₅₀ ) on the volume basis reached 5.2 μm, an aqueous solution in which 2 parts by mass of sodium chloride was dissolved in 20 ml of ion-exchanged water was added. Then, the particle growth is stopped, and further, the shape is controlled by continuing the fusion by heating and stirring at 95 ° C. for 10 hours, and then the system is cooled to 30 ° C., and hydrochloric acid is added. The pH was adjusted to 2.0 and stirring was stopped.

  The produced particles were filtered, washed repeatedly with ion exchange water at 45 ° C., and then dried with hot air at 40 ° C. to obtain colored particles (K1).

<Manufacture of colored particles (K2)>
In the production of the colored particles (K1), the hybrid resin particles (2) are used instead of the hybrid resin particles (1), the wax dispersion (2) is used instead of the wax dispersion (1), and the dispersion The pH of the mixed solution was adjusted to 11.0, and the particle growth was stopped when the median diameter (D ₅₀ ) on the volume basis became 5.5 μm, in the same manner as in the production of the colored particles (K1). Colored particles (K2) were obtained.

<Production of colored particles (K3)>
In the production of the colored particles (K1), the hybrid resin particles (3) are used instead of the hybrid resin particles (1), the wax dispersion (3) is used instead of the wax dispersion (1), and the dispersion The pH of the mixed solution was adjusted to 10.5, and the growth of the particles was stopped when the median diameter (D ₅₀ ) on the volume basis reached 5.5 μm, in the same manner as in the production of the colored particles (K1). Colored particles (K3) were obtained.

<Production of colored particles (Y1)>
In the production of the colored particles (K1), when the colorant dispersion (2) is used instead of the colorant dispersion (1), the particle growth occurs when the median diameter (D ₅₀ ) on the volume basis becomes 5.5 μm. Colored particles (Y1) were obtained in the same manner as in the production of the colored particles (K1) except that was stopped.

<Production of colored particles (Y2)>
In the production of the colored particles (K2), the colorant dispersion (2) is used instead of the colorant dispersion (1), the pH of the dispersion liquid mixture is adjusted to 9.0, and the median diameter on the volume basis ( Colored particles (Y2) were obtained in the same manner as in the production of the colored particles (K2) except that the particle growth was stopped when D ₅₀ ) became 5.4 μm.

<Production of colored particles (Y3)>
In the production of the colored particles (K3), when the colorant dispersion (2) is used instead of the colorant dispersion (1), the particle growth occurs when the median diameter (D ₅₀ ) on the volume basis becomes 5.3 μm. Colored particles (Y3) were obtained in the same manner as in the production of the colored particles (K3) except that was stopped.

<Manufacture of colored particles (M1)>
In the production of the colored particles (K1), when the colorant dispersion (3) is used instead of the colorant dispersion (1), the particle growth occurs when the median diameter (D ₅₀ ) on the volume basis becomes 5.5 μm. Colored particles (M1) were obtained in the same manner as in the production of the colored particles (K1) except that was stopped.

<Production of colored particles (M2)>
In the production of the colored particles (K2), the colorant dispersion (3) is used instead of the colorant dispersion (1), the pH of the dispersion liquid mixture is adjusted to 9.0, and the median diameter (volume basis) ( Colored particles (M2) were obtained in the same manner as in the production of the colored particles (K2) except that the particle growth was stopped when D ₅₀ ) became 5.4 μm.

<Manufacture of colored particles (M3)>
In the production of the colored particles (K3), when the colorant dispersion (3) is used instead of the colorant dispersion (1), the particle growth occurs when the median diameter (D ₅₀ ) on the volume basis becomes 5.3 μm. Colored particles (M3) were obtained in the same manner as in the production of the colored particles (K3) except that was stopped.

<Manufacture of colored particles (C1)>
In the production of the colored particles (K1), when the colorant dispersion (4) is used instead of the colorant dispersion (1), the particle growth occurs when the median diameter (D ₅₀ ) on the volume basis becomes 5.5 μm. Colored particles (C1) were obtained in the same manner as in the production of the colored particles (K1) except that was stopped.

<Production of colored particles (C2)>
In the production of the colored particles (K2), the colorant dispersion (4) is used in place of the colorant dispersion (1), the pH of the dispersion liquid mixture is adjusted to 9.0, and the median diameter on a volume basis ( Colored particles (C2) were obtained in the same manner as in the production of the colored particles (K2) except that the particle growth was stopped when D ₅₀ ) became 5.4 μm.

<Production of colored particles (C3)>
In the production of the colored particles (K3), when the colorant dispersion (4) is used instead of the colorant dispersion (1), the particle growth occurs when the median diameter (D ₅₀ ) on the volume basis becomes 5.3 μm. Colored particles (C3) were obtained in the same manner as in the production of the colored particles (K3) except that was stopped.

<Example of toner production>
In each of 100 parts by mass of the above 16 kinds of colored particles (K1) to colored particles (C3), 1.0 part by mass of silica having a number average primary particle diameter of 12 nm and a degree of hydrophobicity of 80, and a number average primary Toner (K1) to toner (C3) were obtained by adding 1.0 part by mass of titania having a particle size of 25 nm and a hydrophobization degree of 80 and mixing using a Henschel mixer.

  The shape and particle size of the toner particles constituting these toners did not change depending on the addition of external additives.

<Production of comparative toner (K4)>
299 parts by mass of terephthalic acid, 211 parts by mass of polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, and 82 parts by mass of pentaerythritol, a thermometer, a stainless steel stirrer, Placed in a round bottom flask equipped with a glass nitrogen gas inlet tube and a falling condenser, and this flask was set in a mantle heater, and nitrogen gas was introduced from the nitrogen gas inlet tube to keep the flask in an inert atmosphere. The temperature was raised. Then, 0.05 parts by mass of dibutyltin oxide was added, and the reaction was conducted at a temperature of 200 ° C. while tracking the reaction at the softening point temperature. Thus, a polyester resin A having a chloroform insoluble content of 17% by mass was produced. This polyester resin A had a glass transition temperature of 59 ° C. and a softening temperature of 131 ° C.

90 parts by mass of polyester resin A with 100 parts by mass of styrene acrylic resin (styrene-derived component and butyl acrylate-derived component in a mass ratio of 72:28, glass transition temperature: 53 ° C., softening point temperature: 121 ° C.) Parts, 6 parts by mass of carbon black and 6 parts by mass of pentaerythritol behenate are mixed, melted, kneaded, cooled, pulverized and classified, and colored particles for comparison having a median diameter (D ₅₀ ) of 6.8 μm on a volume basis ( K4), and then 1.0 part by mass of silica having a number average primary particle diameter of 12 nm and a hydrophobization degree of 80, and 1.0 mass of titania having a number average primary particle diameter of 25 nm and a hydrophobization degree of 80. And a toner for comparison (K4) was obtained by mixing using a Henschel mixer.

<Production of Comparative Toner (Y4)>
In the production of the comparative toner (K4), the median diameter on a volume basis is the same as that of the comparative colored particles (K4) except that 8 parts by mass of the pigment “CI Pigment Yellow 185” is used instead of carbon black. A comparative colored particle (Y4) having a (D ₅₀ ) of 6.4 μm was obtained, and a comparative toner (Y4) was obtained in the same manner as in the production of the comparative toner (K4).

<Manufacture of comparative toner (M4)>
In the production of the comparative toner (K4), in the same manner as the comparative colored particles (K4), except that 9 parts by mass of quinacridone-based magenta pigment “CI Pigment Red 122” was used instead of carbon black. A comparative colored particle (M4) having a median diameter (D ₅₀ ) of 6.4 μm was obtained, and a comparative toner (M4) was obtained in the same manner as in the production of the comparative toner (K5).

<Production of Comparative Toner (C4)>
In the production of the comparative toner (K4), the same procedure as for the comparative colored particles (K4) except that 9 parts by mass of a phthalocyanine cyan pigment “CI Pigment Blue 15: 3” was used instead of carbon black. Comparative colored particles (C4) having a median diameter (D ₅₀ ) of 6.4 μm on a volume basis were obtained, and a comparative toner (C4) was obtained in the same manner as in the production of comparative toner K4.

Table 1 shows the resin used for the production of the toner, the production method, and the median diameter (D ₅₀ ) of the obtained toner on the volume basis.

The median diameter (D ₅₀ ) based on the toner volume is measured and calculated using a device in which a computer system for data processing (manufactured by Beckman Coulter) is connected to Coulter Multisizer 3 (manufactured by Beckman Coulter). did.

<Developer>
16 parts by mass of each of the 12 types of toners (K1) to (C3) and the 4 types of comparative toners (K4) to (C4) manufactured as described above, and a median diameter on a volume basis coated with an acrylic resin ( Developers (K1) to (C3) and comparative developers (K4) to (C4) were produced by mixing 400 parts by mass of ferrite carrier having D ₅₀ ) of 45 μm.

<Image forming apparatus>
As an image forming apparatus, a tandem full-color copier “8050” (manufactured by Konica Minolta Business Technologies), a contact heating fixing apparatus including a heating belt and a pressure belt shown in FIG. Installed.

Heating belt: Belt coated with polytetrafluoroethylene with 15 μm conductive material dispersed on 70 μm polyimide film surface Pressure belt: Belt coated with 200 μm silicone rubber on 70 μm polyimide film surface Heat source: Halogen lamp Heating belt surface Temperature = 140 ° C
Pressing force of the pressure contact members AS1 and AS2 = 300N
Nip width: 25mm
<Evaluation>
The evaluation was performed for the following items by sequentially loading the image forming apparatus with the toner and the developer prepared above to form an image. The evaluation criteria are ◎, ○, and △, and × indicates failure due to practical problems.

<Fixing offset>
Fixing offset is a full-color image (yellow / magenta / cyan / black with 5% of each pixel) on high-quality A4 size paper (65 g / m ² ) in a low-temperature, low-humidity environment of 10 ° C. and 20% RH. Used, 50,000 continuous prints were made. Regarding the fixing offset, a solid white image was printed after 50,000 sheets, and the presence or absence of contamination was visually determined. Further, the presence or absence of toner contamination transferred to the pressure belt side was also visually determined.

Evaluation criteria A: No stain on the image and no stain on the surface of the pressure belt ○: No stain on the image, but some stain on the pressure belt surface ×: Dirt on the image Occurs, the pressure belt surface is also dirty, and the image back surface is also dirty.

<Whether or not winding occurs during double-sided printing>
Whether or not there is wrapping during double-sided printing is as follows. Full color images (yellow / magenta / cyan / black) are printed on A4 size high-quality paper (65 g / m ² ) in a low-temperature, low-humidity environment at 10 ° C. and 20% RH 25% (100 pixel ratio) was continuously printed on both sides.

  The leading edge of the image was formed within 1 mm from the leading edge of the fine paper, 500 continuous printings were performed, and the presence or absence of winding on the heating belt side was evaluated.

Evaluation criteria ○: No winding up to 500 sheets ×: Winding around the heating belt occurred up to the 500th sheet.

  The evaluation results are shown in Table 2.

  As is clear from Table 2, there was no problem in any evaluation in the image formation of Examples 1 to 3 performed using the toner according to the present invention and the contact heat fixing device according to the present invention.

  On the other hand, in the image formation of Comparative Example 1 using the comparative toner and the comparative contact heat fixing device, there was a problem in any of the evaluation items, and the object of the present invention could not be achieved.

It is a perspective view which shows an example of a reaction apparatus. FIG. 3 is a schematic diagram illustrating an example of a contact heating type fixing device having a belt-shaped heating unit and a belt-shaped pressurizing unit. It is the schematic which shows an example of the contact heating fixing apparatus comprised by the heating belt and pressure belt which are used by this invention. 1 is a cross-sectional configuration diagram illustrating an example of an image forming apparatus used in the present invention.

Explanation of symbols

24 fixing device 241 heating belt 242 pressure belt 243 roller 244 roller 245a, 245b roller 246a, 246b roller AS1, AS2 pressure contact member DB1, DB2 elastic member HL1 heat source N nip portion P transfer material SB1, SB2 support member

Claims (3)

In an image forming method having a step of fixing a toner image formed using toner composed of toner particles containing at least a resin and a colorant on a support using a contact heating type fixing device,
The resin constituting the toner particles contains a polyester resin and a styrene acrylic resin,
The toner particles are in an aqueous medium.
Radical polymerization containing at least one polycarboxylic acid and at least one polycondensable monomer containing a polyhydric alcohol, and at least one styrene compound and at least one (meth) acrylic acid ester compound mixed sex monomer to form oil droplets of the hybrid resin particle-forming composition, after forming the polyester resin by polycondensation between the polyhydric alcohol and the polyvalent carboxylic acid in the oil droplets, wherein A hybrid resin particle is obtained by radical copolymerization of a radical polymerizable monomer to form a styrene acrylic resin, and is obtained by aggregating at least the hybrid resin particle and the colorant particle in an aqueous medium. Yes,
An image forming method, wherein the contact heating type fixing device includes a belt-shaped heating unit and a belt-shaped pressing unit. The image forming method according to claim 1, wherein the polyester resin has a number average molecular weight (Mn) measured by gel permeation chromatography of 1,000 to 10,000. The image forming method according to claim 1, wherein the styrene acrylic resin has a number average molecular weight (Mn) measured by gel permeation chromatography of 1,000 to 100,000.

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