JP7218619B2 - Toner and image forming method - Google Patents

Description

The present invention relates to toners and image forming methods.

Conventionally, an electrostatic latent image formed on a photoreceptor is developed with toner to form a toner image, the formed toner image is transferred to paper, and the transferred toner image is heat-fixed. 2. Description of the Related Art There is known an electrophotographic image forming apparatus that forms an image on a sheet of paper. In such an image forming apparatus, in order to fix a toner image on paper by heat fixing, the toner needs to be heated to a high temperature and melted once. Therefore, there is a limit to how much energy can be saved.

In recent years, in order to save energy during image formation, improve operability, and expand the types of compatible media, systems have been proposed in which fixing is performed by an external stimulus other than heat. Among them, an optical fixing system, which is relatively easily adapted to the electrophotographic process, has attracted attention, and a developer that is softened by light (photo-melting toner) has been reported.

For example, Patent Document 1 discloses a developer containing a compound that contains a binder resin, a colorant, and an additive, and that the additive undergoes a cis-trans isomerization reaction upon absorption of light to undergo a phase transition. ing. Further, in Patent Document 1, as a fixing method using such a developer, a toner image transferred to paper is irradiated with light to melt a compound that undergoes a phase transition due to light absorption, and then light is irradiated again. Then, a technique is disclosed in which the toner image is fixed on paper by solidifying the compound.

Furthermore, Patent Document 2 discloses an image forming apparatus using a developer containing a compound that undergoes a cis-trans isomerization reaction upon absorption of light and undergoes a phase transition. An example of such an image forming apparatus is an exposure apparatus that irradiates light toward a nip position where a conveying belt is sandwiched between a photoreceptor and a transfer roller when forming an image on a recording sheet made of transparent resin. has been proposed.

JP 2014-191078 A JP 2014-191077 A

However, the toner images obtained using the developers described in Patent Documents 1 and 2 have a problem that the fixability of the image is not sufficient.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide means for improving the fixability of an image in a fixing method using light irradiation.

The present inventors have accumulated earnest research. As a result, the above problem is solved by a toner containing a predetermined block copolymer containing a polymer block containing a structural unit derived from an azobenzene derivative and a thermoplastic resin polymer block having no azobenzene group. and completed the present invention.

That is, the present invention is a toner containing a polymer compound represented by the following general formula (1).

In the general formula (1), A is a polymer block containing a structural unit derived from an azobenzene derivative having a polymerizable group, and B is a polymer block of a thermoplastic resin having no azobenzene group.

According to the present invention, there is provided means for improving the fixability of an image in a fixing method using light irradiation.

1 is a schematic configuration diagram showing an image forming apparatus according to one embodiment of the present invention; FIG. 2 is a schematic configuration diagram of an irradiation unit in the image forming apparatus; FIG.

The present invention is a toner containing a polymer compound represented by the following general formula (1).

In the general formula (1), A is a polymer block containing a structural unit derived from an azobenzene derivative having a polymerizable group, and B is a polymer block of a thermoplastic resin having no azobenzene group.

The toner of the present invention containing a block copolymer containing such a structural unit derived from an azobenzene derivative has an improved softening speed upon light irradiation and is excellent in image fixability.

Although the details of why the toner of the present invention achieves the above effects are unknown, the following mechanism is conceivable. The mechanism described below is based on speculation, and the present invention is not limited to the mechanism described below. In the following description, the polymer compound represented by the general formula (1) is also simply referred to as "the polymer compound of the present invention".

Azobenzene compounds are known to be materials that absorb light and soften from a solid state (optical phase transition), and the optical phase transition of azobenzene compounds is thought to be caused by cis-trans isomerization. Some materials are known that reversibly soften and melt from a solid state using the cis-trans isomerization reaction of azobenzene compounds. Patent Documents 1 and 2 above describe a system in which these materials are contained and the toner is softened by light irradiation. Even in such a state, there is a problem that the strength of the fixed image is low.

In the present invention, the azobenzene derivative component and the thermoplastic resin component are polymerized so as to form a block copolymer structure and incorporated into the toner. When polymerized, the azobenzene group absorbs light, and the heat energy released during the photoexcitation/deactivation process is transmitted to the repeating unit (structural unit) that bonds (photothermal conversion), softening and melting the toner image. Or soften. In addition, it is considered that the formation of a block copolymer facilitates the formation of domains in the toner by the azobenzene derivative, thereby effectively inducing softening and melting. In addition, since the thermoplastic resin component is included in the same polymer, softening and melting are effectively transferred, and it is considered possible to induce a large softening and melting phenomenon in the toner as a whole. Furthermore, the azobenzene derivative is polymerized and contains a thermoplastic resin component, so it is thought that the toughness is improved and excellent image strength can be obtained.

Preferred embodiments of the present invention are described below. In this specification, "X to Y" indicating a range means "X or more and Y or less". In this specification, unless otherwise specified, operations and measurements of physical properties are performed under the conditions of room temperature (20 to 25° C.)/relative humidity of 40 to 50% RH.

[Constitution of Toner]
The toner of the present invention comprises a polymer block (A) containing a structural unit derived from an azobenzene derivative having a polymerizable group, and a polymer block B of a thermoplastic resin having no azobenzene group. It includes polymeric compounds (block copolymers) having any of the pentablock copolymer structures.

Among the above block copolymer structures, from the viewpoint of ease of softening and melting and image strength, the block copolymer structure of ABA or BAB is preferable, and ABA is more preferably a block copolymer structure of

<Polymer Block (A) Containing Structural Unit Derived from Azobenzene Derivative Having Polymerizable Group>
The polymer block (A) containing a structural unit derived from an azobenzene derivative having a polymerizable group contains a structural unit derived from the azobenzene derivative (a) having a polymerizable group. The polymer block (A) is a polymer block obtained by polymerizing an azobenzene derivative (a) (azobenzene derivative monomer) having a polymerizable group.

The number of polymerizable groups contained in one molecule of the azobenzene derivative (a) having a polymerizable group may be one, or two or more. Among them, the number of polymerizable groups contained in one molecule of the azobenzene derivative (a) having a polymerizable group is one from the viewpoint that a polymer that is easily melted can be easily obtained even with a low amount of light irradiation energy. It is preferably a monofunctional polymerizable monomer.

The polymerizable group includes a (meth)acryloyl group, an epoxy group, and a vinyl group, preferably a (meth)acryloyl group or a vinyl group. Anion polymerization, cationic polymerization, and living radical polymerization are known as methods for synthesizing block copolymers. Among them, simple synthesis methods include living radical polymerization methods such as the ATRP method and the RAFT method. If the polymerizable group is a (meth)acryloyl group or a vinyl group, it is preferable because a living radical polymerization method such as ATRP method or RAFT method can be used. Among them, a (meth)acryloyl group is preferred. In addition, a (meth)acryloyl group means an acryloyl group and a methacryloyl group.

That is, the azobenzene derivative (a) having a polymerizable group preferably has a group represented by any one of the following formulas (i) to (iii) as a group having a polymerizable group. It is preferable to contain a group having the following polymerizable group, since it is suitable for synthesis of a block copolymer by a living radical polymerization method. Among these, from the viewpoint of ease of softening and melting, it preferably contains a group having a polymerizable group (ii) or (iii), and more preferably contains a group having a polymerizable group (iii).

In formulas (i) to (iii), each R ₁ is independently a hydrogen atom or a methyl group. Each R ₂ is independently an alkylene group having 1 to 18 carbon atoms. The alkylene group having 1 to 18 carbon atoms is preferably an alkylene group having 3 to 10 carbon atoms. The alkylene group may be linear or branched, preferably linear. A part of the alkylene group may be substituted with a substituent. Examples of substituents include halogen groups, nitro groups, hydroxy groups, carboxy groups, and the like.

The azobenzene derivative (a) having a polymerizable group is preferably a compound represented by the following formula (2).

In formula (2), any one of X ₁ to X ₃ is a group having a polymerizable group, and the rest are hydrogen atoms. The group having a polymerizable group is preferably a group represented by any one of formulas (i) to (iii) above, more preferably a group represented by formula (iii).

R ₃ to R ₅ each independently represents a hydrogen atom, a halogen group, a nitro group, a hydroxy group, a carboxy group, an alkyl group having 1 to 16 carbon atoms, an alkoxy group having 1 to 16 carbon atoms, or a number of carbon atoms. It is an acyl group having 2 to 16 carbon atoms, an alkoxycarbonyl group having 2 to 16 carbon atoms, or an acyloxy group having 2 to 16 carbon atoms. A halogen group refers to a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), or an iodo group (-I). an alkyl group having 1 to 16 carbon atoms, an alkoxy group having 1 to 16 carbon atoms, an acyl group having 2 to 16 carbon atoms, an alkoxycarbonyl group having 2 to 16 carbon atoms, or an acyloxy group having 2 to 16 carbon atoms Each group is an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an acyl group having 2 to 12 carbon atoms, an alkoxycarbonyl group having 2 to 12 carbon atoms, or a An acyloxy group having 2 to 12 carbon atoms is preferable, and an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an acyl group having 2 to 8 carbon atoms, and an acyl group having 2 to 8 carbon atoms, respectively. or an acyloxy group having 2 to 8 carbon atoms. A part of the above alkyl group, alkoxy group, acyl group, alkoxycarbonyl group or acyloxy group may be substituted with a substituent. Examples of substituents include halogen groups, nitro groups, hydroxy groups, carboxy groups, and the like. The above alkyl group, alkoxy group, acyl group, alkoxycarbonyl group, or acyloxy group may be linear or branched. It is more preferably chain-like.

Further, from the viewpoint of ease of photoisomerization, each of R ₃ to R ₅ is independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 8 carbon atoms. is more preferred. Such compounds have relatively weak intermolecular interactions while having high thermal mobility. Therefore, it is considered that the cis-trans isomerization by light irradiation proceeds more easily, and the softening speed of the toner and the fixability of the image are further improved.

Among them, the azobenzene derivative (a) having a polymerizable group is represented by the following formula (3) from the viewpoint of facilitating photoisomerization and thereby facilitating melting or softening of the toner image even by light irradiation with lower energy. It is preferably a compound represented by

In formula (2), X ₁ and R ₃ are synonymous with X ₁ and R ₃ in formula (2), respectively. That is, X ₁ is a group having the polymerizable group, and R ₃ is a hydrogen atom, a halogen group, a nitro group, a hydroxy group, a carboxy group, an alkyl group having 1 to 16 carbon atoms, or an alkyl group having 1 to 16 carbon atoms. 16 alkoxy groups, acyl groups having 2 to 16 carbon atoms, alkoxycarbonyl groups having 2 to 16 carbon atoms, or acyloxy groups having 2 to 16 carbon atoms.

Furthermore, from the viewpoint of facilitating photoisomerization and thereby facilitating melting or softening of the toner image even with lower-energy light irradiation, the azobenzene derivative (a) having a polymerizable group is represented by the following formula (4): Particularly preferred are the compounds represented.

In formula (4), R ₁ is a hydrogen atom or a methyl group, R ₂ is an alkylene group having 1 to 18 carbon atoms, and R ₃ is a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. , or an alkoxy group having 1 to 8 carbon atoms.

<Method for preparing an azobenzene derivative having a polymerizable group>
A method for preparing the azobenzene derivative having a polymerizable group is not particularly limited. For example, it can be prepared by first preparing a desired azobenzene derivative and introducing a group having a polymerizable group into the obtained azobenzene derivative.

The azobenzene derivative is not particularly limited, but for example, in the first step, an aniline derivative and sodium nitrite are reacted under cooling to produce a diazonium salt, which is then reacted with a phenol to produce an intermediate (4- A phenyldiazenyl)phenol compound is obtained. For example, when obtaining the compound of the above formula (4), the following intermediate A can be obtained using an aniline derivative having R ₃ at the para position and phenol as raw materials.

After that, as a second step, a polymerizable group is introduced into the intermediate A described above. A method for introducing a group having a polymerizable group is also not particularly limited. For example, when obtaining the compound of the above formula (4), in order to introduce the linker moiety R ₂ into the intermediate A, X—R ₂ —OH, which is a halogenated alcohol compound of R ₂ , is allowed to act to obtain the following Intermediate B is obtained.

After that, as the third step, the intermediate B is reacted with a compound for forming a group having a polymerizable group, for example, an acrylate or a methacrylate when obtaining the compound (4) above. Reaction conditions are not particularly limited. For example, it is preferable to carry out the reaction in a known organic solvent in the presence of tertiary amines such as triethylamine and triethanolamine. Preferably, an acrylate or methacrylate is added dropwise to the mixture containing intermediate B, amines, and solvent while maintaining the mixture at 0 to 10°C. After that, the mixed solution is reacted at room temperature for about 5 to 10 hours to obtain an azobenzene derivative having a polymerizable group.

In addition, in said 1st step, the azobenzene derivative which has a desired substituent can be obtained by changing the raw material to be used to another compound. Also, by changing the compounds added in the second and third stages, groups having different structures of polymerizable groups can be introduced. A person skilled in the art can synthesize an azobenzene derivative containing a group having a desired polymerizable group by appropriately making the above changes and selecting appropriate reaction conditions.

Moreover, in the first step, a group having a polymerizable group can be introduced into the intermediate A without performing the second step by appropriately selecting the raw materials to be used.

<Polymer block B which is a thermoplastic resin having no azobenzene group>
The polymer block B is a thermoplastic resin that softens when heated, and is not particularly limited as long as the structural units constituting the polymer block B do not contain an azobenzene group.

The structural unit constituting the polymer block B preferably has a vinyl-based polymerizable group from the viewpoint of application to the synthesis of block copolymers by living radical polymerization methods such as the ATRP method and the RAFT method. . Specifically, for example, styrene derivatives, (meth)acrylic acid derivatives, olefin derivatives, vinyl ester derivatives, vinyl ether derivatives, vinyl ketone derivatives and the like are used. is preferred. That is, the polymer block B, which is a thermoplastic resin having no azobenzene group, is preferably a polymer block containing at least one structural unit derived from a styrene derivative, (meth)acrylic acid derivative, or olefin derivative. .

Styrene derivatives include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene and p-tert-butylstyrene. , pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene and the like.

(Meth)acrylic acid derivatives include (meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, stearyl (meth) acrylate, dodecyl (meth) acrylate, phenyl (meth) acrylate, diethylaminoethyl ( meth)acrylate, dimethylaminoethyl (meth)acrylate and the like.

Olefin derivatives include ethylene, propylene, n-butylene, isobutylene, n-pentene and the like.

Vinyl ester derivatives include vinyl propionate, vinyl acetate, vinyl benzoate and the like. Vinyl ether derivatives include vinyl methyl ether and vinyl ethyl ether. Vinyl ketone derivatives include vinyl methyl ketone, vinyl ethyl ketone, vinyl hexyl ketone and the like.

The number average molecular weight (total number average molecular weight) of the polymer block A contained in the polymer compound represented by the general formula (1) in the present invention is not particularly limited, but is preferably 1000 or more, more preferably It is 1,000 to 100,000, more preferably 1,000 to 70,000, still more preferably 1,000 to 50,000, and particularly preferably 3,000 to 50,000. If the total number average molecular weight of the polymer block A is 1000 or more, a toner image with excellent fixability can be obtained more easily, which is preferable. Further, if the total number average molecular weight of the polymer blocks A is 100,000 or less, the efficiency of softening and melting becomes high, which is preferable. Here, the total number average molecular weight of the polymer blocks A refers to the number average molecular weight of the polymer block A when the polymer compound represented by the general formula (1) contains a single polymer block A. , means the total sum of the number average molecular weights of each polymer block A when a plurality of polymer blocks A are included.

The number average molecular weight (total number average molecular weight) of polymer block B contained in the polymer compound represented by general formula (1) is not particularly limited, but is preferably 1000 or more, more preferably 1000 to 100000. , more preferably 1,000 to 70,000, even more preferably 1,000 to 50,000, and particularly preferably 3,000 to 50,000. If the total number average molecular weight of the polymer block B is 1000 or more, a toner image with excellent fixability can be obtained more easily, which is preferable. Moreover, if the total number average molecular weight of the polymer blocks B is 100,000 or less, the efficiency of softening and melting becomes high, which is preferable. Here, the total number average molecular weight of the polymer blocks B refers to the number average molecular weight of the polymer block B when the polymer compound represented by the general formula (1) contains a single polymer block B. , means the sum of the number average molecular weights of each polymer block B when a plurality of polymer blocks B are included.

Further, the total number average molecular weight Mn of the polymer compound represented by the general formula (1) is preferably 3500 or more, more preferably 3500 to 100000, even more preferably 3500 to 70000, still more preferably 3,500 to 50,000, particularly preferably 5,000 to 50,000. If the total number average molecular weight of the polymer compound represented by general formula (1) is 3500 or more, a toner image with excellent fixability can be obtained more easily, which is preferable. Further, if the total number average molecular weight is 100,000 or less, the efficiency of softening and melting becomes high, which is preferable.

Therefore, according to a preferred embodiment of the present invention, in the toner of the present invention, the total number average molecular weight of polymer blocks A contained in the polymer compound represented by formula (1) is 1000 or more, The total number average molecular weight of the polymer blocks B is 1000 or more, and the total number average molecular weight Mn of the polymer compound represented by the general formula (1) is 3500 or more.

In the polymer compound represented by the general formula (1) of the present invention, the ratio between the total number average molecular weight of the polymer block A and the total number average molecular weight of the polymer B is not particularly limited. From the viewpoint of ease of use and image strength, the ratio of the total number average molecular weight of the polymer block A to the total number average molecular weight of the polymer block B is preferably 1:20 to 20:1, more preferably 1:15. ~15:1 is more preferred.

The number average molecular weight of the polymer compound represented by the general formula (1) of the present invention and the number average molecular weights of the polymer blocks A and B contained in the polymer compound represented by the general formula (1) are determined by gel permeation chromatography. It can be measured by graphics (GPC). Specifically, it can be measured by the method described in Examples below.

The glass transition temperature (Tg) of the polymer compound represented by the general formula (1) is preferably 25 to 100° C. from the viewpoint of heat-resistant storage stability and efficient induction of softening and melting due to light irradiation. It is more preferably 30 to 80°C. The glass transition temperature (Tg) of the polymer compound represented by the above general formula (1) is the content ratio of the polymer block A obtained by polymerizing the azobenzene derivative and the polymer block B of the thermoplastic resin. It can be adjusted by the type of resin constituting the polymer block B of the resin, the structure of the block copolymer, the molecular weight, and the like. The glass transition temperature of the polymer compound represented by general formula (1) can be measured by the method described in Examples.

<Method for preparing block copolymer>
A method for synthesizing the polymer compound (block copolymer) represented by formula (1) is not particularly limited, and known methods such as anionic polymerization, cationic polymerization, and living radical polymerization can be used. Among them, a living radical polymerization method such as an atom transfer radical polymerization method (ATRP method) or a RAFT method can be suitably used as a simple synthesis method.

Taking the ATRP method as an example, a compound containing a monofunctional, difunctional, trifunctional, or tetrafunctional halogen element is used as a starting material as an initiator, and a monomer that becomes a structural unit of the polymer block A or B is used as a catalyst. It can be carried out by a method such as polymerizing under

In the step of polymerizing a monomer, for example, a monomer that becomes a structural unit of either polymer block A or B (the block that becomes the core portion of the block copolymer) in the presence of an initiator, a catalyst and a ligand is polymerized to produce a macroinitiator.

Examples of the initiator include butyl 2-bromoisobutyrate, ethylenebis(2-bromoisobutyrate), 1,1,1-tris(2-bromoisobutyryloxymethyl)ethane, pentaerythritol tetrakis(2- bromoisobutyrate), α,α'-dibromo-p-xylene, ethyl bromoacetate, 2-bromoisobutyryl bromide, or mixtures thereof, etc., but not limited thereto.

Catalysts include copper (I) catalysts, iron (II) catalysts, and the like, and examples thereof include Cu(I)Cl, Cu(I)Br, Fe(II)Cl, Fe(II)Br, and mixtures thereof. can do.

Known ligands can be used, and 2,2′-bipyridyl, 4,4′-dimethyl-2,2′-bipyridyl, 4,4′-di-tert-butyl-2, 2′-bipyridyl, 1,1,4,7,10,10-hexamethyltriethylenetetramine, N,N,N′,N″,N″-pentamethyldiethylenetriamine, cyclam (1,4,8,11- tetraazacyclotetradecane), 1,4,8,11-tetramethylcyclam (1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane), tris[2-(dimethyl At least one selected from the group consisting of amino)ethyl]amine and the like is preferable.

The amounts of the catalyst and ligand used are not particularly limited, and can be appropriately determined with reference to conventionally known knowledge.

Next, the macroinitiator obtained by the above polymerization is isolated and used as an initiator, and in the presence of a catalyst and a ligand again, among the monomers that become the structural units of the polymer block A or B, the macroinitiator Polymerization of the monomer not used in the synthesis of is carried out. Alternatively, at the stage when almost all the monomers are consumed in the synthesis of the macroinitiator, the monomers not used in the synthesis of the macroinitiator may be added without isolating the macroinitiator, and the polymerization may be continued. . Through these operations, the target block copolymer can be obtained.

Each of the above reactions is preferably carried out in an inert atmosphere such as nitrogen or a rare gas such as argon. Each of the above reactions can be carried out at a temperature of, for example, 25-160°C, preferably 35-130°C. Moreover, each of the above reactions may be carried out without using a solvent, or may be carried out in a solvent such as an organic solvent.

A reaction to obtain a macroinitiator by polymerizing a monomer that forms the structural unit of either polymer block A or B, and a reaction of the macroinitiator with a monomer that forms the structural unit of the other polymer block. In the reaction to obtain the block copolymer, conditions such as the type and amount of the catalyst and ligand used, and the temperature during the reaction may be the same or different.

<Binder resin>
The toner of the present invention may further contain a binder resin.

The binder resin is a resin that does not have an azobenzene group, and any resin that is generally used as a binder resin that constitutes a toner can be used without limitation. Examples of binder resins that can be used include styrene resins, acrylic resins, styrene-acrylic resins, polyester resins, silicone resins, olefin resins, amide resins, and epoxy resins. These binder resins can be used alone or in combination of two or more.

Among these, the binder resin is at least one selected from the group consisting of styrene resins, acrylic resins, styrene-acrylic resins, and polyester resins, from the viewpoint of having low viscosity when melted and high sharp-melting properties. and more preferably at least one selected from the group consisting of styrene-acrylic resins and polyester resins.

(styrene acrylic resin)
The styrene-acrylic resin referred to in the present invention is a polymer containing at least a structural unit derived from a styrene monomer and a structural unit derived from a (meth)acrylic acid ester monomer. Here, the styrene monomer includes not only styrene represented by the structural formula of CH ₂ ═CH—C ₆ H ₅ but also those having a known side chain or functional group in the styrene structure.

Examples of the styrene monomer include those similar to the styrene monomer that can constitute the polymer compound described above.

A (meth)acrylic acid ester monomer has a functional group having an ester bond in its side chain. Specifically, in addition to acrylic acid ester monomers represented by CH ₂ =CHCOOR (R is an alkyl group), methacrylic acid esters represented by CH ₂ =C(CH ₃ )COOR (R is an alkyl group) Vinyl ester compounds such as monomers are included. (Meth)acrylic acid in the (meth)acrylic acid ester monomer means acrylic acid and methacrylic acid.

Examples of (meth)acrylate monomers include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl ( meth)acrylate, tert-butyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, stearyl (meth)acrylate, dodecyl (meth)acrylate, phenyl (meth)acrylate, diethylaminoethyl (meth)acrylate ) acrylate, dimethylaminoethyl (meth)acrylate, and the like.

The styrene monomer and the (meth)acrylic acid ester monomer can be used either alone or in combination of two or more.

The content of the structural unit derived from the styrene monomer and the structural unit derived from the (meth)acrylic acid ester monomer in the styrene acrylic resin is not particularly limited, and the softening point and glass transition temperature of the binder resin are controlled. It can be adjusted as appropriate from the viewpoint of Specifically, the content of structural units derived from styrene monomers is preferably 40 to 95% by mass, more preferably 50 to 80% by mass, relative to the total amount of monomers. . In addition, the content of structural units derived from (meth) acrylic acid ester monomers is preferably 5 to 60% by mass, more preferably 10 to 50% by mass, with respect to the total amount of monomers. preferable.

The styrene-acrylic resin may further contain structural units derived from monomers other than the styrene monomer and the (meth)acrylic acid ester monomer, if necessary. Examples of other monomers include vinyl monomers. Examples of vinyl monomers that can be used in combination when forming the styrene-acrylic copolymer of the present invention are shown below, but the vinyl monomers that can be used in combination are not limited to those shown below.

(1) Olefins Ethylene, propylene, isobutylene, etc. (2) Vinyl esters Vinyl propionate, vinyl acetate, vinyl benzoate, etc. (3) Vinyl ethers Vinyl methyl ether, vinyl ethyl ether, etc. (4) Vinyl ketones Vinyl methyl ketone, Vinyl ethyl ketone, vinyl hexyl ketone, etc. (5) N-vinyl compounds N-vinylcarbazole, N-vinylindole, N-vinylpyrrolidone, etc. (6) Others Vinyl compounds such as vinylnaphthalene and vinylpyridine, acrylonitrile, methacrylo acrylic or methacrylic acid derivatives such as nitrile and acrylamide;

It is also possible to produce a crosslinked resin using a polyfunctional vinyl monomer. Furthermore, it is also possible to use vinyl monomers having ionic dissociation groups in their side chains. Specific examples of ionic dissociation groups include carboxyl groups, sulfonic acid groups, and phosphoric acid groups. Specific examples of vinyl monomers having these ionic dissociation groups are shown below.

Specific examples of vinyl monomers having a carboxyl group include acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumaric acid, maleic acid monoalkyl esters, and itaconic acid monoalkyl esters. .

The method of forming the styrene-acrylic resin is not particularly limited, and examples thereof include a method of polymerizing monomers using a known oil-soluble or water-soluble polymerization initiator. For example, a known chain transfer agent such as n-octylmercaptan may be used as required.

When forming the styrene-acrylic resin used in the present invention, the contents of the styrene monomer and the (meth)acrylic acid ester monomer are not particularly limited. It is possible to make appropriate adjustments from the viewpoint of temperature control. Specifically, the content of the styrene monomer is preferably 40 to 95% by mass, more preferably 50 to 80% by mass, based on the total monomers. Also, the content of the (meth)acrylic acid ester monomer is preferably 5 to 60% by mass, more preferably 10 to 50% by mass, based on the total amount of monomers.

The method of forming the styrene-acrylic resin is not particularly limited, and examples thereof include a method of polymerizing monomers using a known oil-soluble or water-soluble polymerization initiator. As the oil-soluble polymerization initiator, for example, the following azo-based or diazo-based polymerization initiators and peroxide-based polymerization initiators are used.

Azo or diazo polymerization initiators include 2,2′-azobis-(2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis(cyclohexane-1 -carbonitrile), 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyronitrile and the like.

Peroxide polymerization initiators include 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, 2,2-bis-(4,4-t-butylperoxycyclohexyl)propane, tris-(t-butylperoxy)triazine and the like.

A water-soluble radical polymerization initiator can also be used when forming styrene-acrylic resin particles by an emulsion polymerization method. Examples of water-soluble radical polymerization initiators include persulfates such as potassium persulfate and ammonium persulfate, azobisaminodipropane acetate, azobiscyanovaleric acid and its salts, and hydrogen peroxide.

The polymerization temperature is preferably 50 to 100.degree. C., more preferably 55 to 90.degree. C., depending on the types of monomers and polymerization initiators used. The polymerization time varies depending on the types of monomers and polymerization initiators used, but is preferably 2 to 12 hours, for example.

The styrene-acrylic resin particles formed by the emulsion polymerization method may have a structure of two or more layers composed of resins having different compositions. In this case, the production method is to add a polymerization initiator and a polymerizable monomer to a dispersion of resin particles prepared by an emulsion polymerization treatment (first stage polymerization) according to a conventional method, and polymerize this system. A multi-stage polymerization method of processing (second-stage, third-stage polymerization) can be employed.

(polyester resin)
A polyester resin is a polyester resin obtained by a polycondensation reaction between a divalent or higher carboxylic acid (polyvalent carboxylic acid component) and a divalent or higher alcohol (polyhydric alcohol component). Incidentally, the polyester resin may be amorphous or crystalline.

The valences of the polyhydric carboxylic acid component and the polyhydric alcohol component are preferably 2 to 3 each, more preferably 2 each. That is, the polyhydric carboxylic acid component preferably contains a dicarboxylic acid component, and the polyhydric alcohol component preferably contains a dialcohol component.

Examples of dicarboxylic acid components include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, and 1,10-decanedicarboxylic acid. (dodecanedioic acid), 1,11-undecanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,13-tridecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,16-hexadecanedicarboxylic acid, 1,18 - saturated aliphatic dicarboxylic acids such as octadecanedicarboxylic acid; unsaturated aliphatic dicarboxylic acids such as methylenesuccinic acid, fumaric acid, maleic acid, 3-hexenedioic acid, 3-octenedioic acid, dodecenylsuccinic acid; Terephthalic acid, isophthalic acid, t-butylisophthalic acid, tetrachlorophthalic acid, chlorophthalic acid, nitrophthalic acid, p-phenylenediacetic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid, anthracenedicarboxylic acid, etc. and the like, and lower alkyl esters and acid anhydrides thereof can also be used. The dicarboxylic acid component may be used alone or in combination of two or more.

In addition, trivalent or higher polyvalent carboxylic acids such as trimellitic acid and pyromellitic acid, their anhydrides, or alkyl esters having 1 to 3 carbon atoms can also be used.

Diol components include, for example, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptane Diol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecane Saturated aliphatic diols such as diols, 1,18-octadecanediol, 1,20-eicosanediol, neopentyl glycol; 2-butene-1,4-diol, 3-butene-1,4-diol, 2-butyne -unsaturated aliphatic diols such as 1,4-diol, 3-butyne-1,4-diol and 9-octadecene-7,12-diol; bisphenols such as bisphenol A and bisphenol F, and ethylene oxide addition of these and aromatic diols such as alkylene oxide adducts of bisphenols such as propylene oxide adducts, and derivatives thereof can also be used. The diol component may be used alone or in combination of two or more.

The method for producing the polyester resin is not particularly limited, and the polyester resin can be produced by polycondensing (esterifying) the polyhydric carboxylic acid component and the polyhydric alcohol component using a known esterification catalyst.

Catalysts that can be used in the production of polyester resins include alkali metal compounds such as sodium and lithium; compounds containing Group 2 elements such as magnesium and calcium; aluminum, zinc, manganese, antimony, titanium, tin, zirconium; compounds of metals such as germanium; phosphite compounds; phosphoric acid compounds; and amine compounds. Specific examples of tin compounds include dibutyltin oxide (dibutyltin oxide), tin octylate, tin dioctate, and salts thereof. Titanium compounds include titanium alkoxides such as tetra-n-butyl titanate (Ti(On-Bu) ₄ ), tetraisopropyl titanate, tetramethyl titanate, and tetrastearyl titanate; titanium acylates such as polyhydroxytitanium stearate; Titanium chelates such as acetylacetonate, titanium lactate, titanium triethanolamine, and the like can be mentioned. Germanium dioxide etc. can be mentioned as a germanium compound. Furthermore, aluminum compounds include polyaluminum hydroxide, aluminum alkoxide, tributylaluminate, and the like. You may use these individually by 1 type or in combination of 2 or more types.

Although the polymerization temperature is not particularly limited, it is preferably 70 to 250°C. Also, the polymerization time is not particularly limited, but it is preferably 0.5 to 10 hours. During the polymerization, the pressure inside the reaction system may be reduced as necessary.

The content ratio of the polymer compound represented by formula (1) and the binder resin is not particularly limited.

The glass transition temperature (Tg) of the toner is preferably 25 to 100.degree. C., more preferably 30 to 80.degree. The glass transition temperature (Tg) of the toner is determined by the content ratio of the polymer block A of the azobenzene derivative and the polymer block B of the thermoplastic resin in the polymer compound of the general formula (1). It can be adjusted according to the type of the constituent resin, the structure of the block copolymer, the molecular weight, and the like. When the toner contains a binder resin, it can be further adjusted by the content ratio of the polymer compound and the binder resin, the type of the binder resin, the molecular weight, and the like. The glass transition temperature of the toner can be measured by the method described in Examples.

The toner of the present invention may be particles having a single layer structure or particles having a core-shell structure. The type of binder resin used for the core particles and the shell portion of the core-shell structure is not particularly limited.

<Colorant>
The toner according to the present invention may contain a colorant. Commonly known dyes and pigments can be used as the colorant.

Colorants for obtaining a black toner include carbon black, magnetic substances, iron-titanium composite oxide black, etc. Carbon black includes channel black, furnace black, acetylene black, thermal black, and lamp black. be Moreover, ferrite, magnetite, etc. are mentioned as a magnetic substance.

As a coloring agent for obtaining a yellow toner, C.I. I. Dyes such as Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112 and 162; I. Pigment Yellow 14, Pigment Yellow 17, Pigment Yellow 74, Pigment Yellow 93, Pigment Yellow 94, Pigment Yellow 138, Pigment Yellow 155, Pigment Yellow 180 and Pigment Yellow 185.

As a colorant for obtaining a magenta toner, C.I. I. Dyes such as Solvent Red 1, 49, 52, 58, 63, 111 and 122; C.I. I. Pigment Red 5, 48:1, 53:1, 57:1, 122, 139, 144, 149, 166, 177, 178, 222.

As a colorant for obtaining a cyan toner, C.I. I. Dyes such as Solvent Blue 25, 36, 60, 70, 93 and 95; C.I. I. Pigment Blue 1, 7, 15, 60, 62, 66, 76 and the like.

Colorants for obtaining toner of each color can be used singly or in combination of two or more for each color.

The content of the colorant in the toner is preferably 0.5 to 20% by mass, more preferably 2 to 10% by mass.

<Release agent>
The toner according to the present invention may contain a releasing agent. The release agent used is not particularly limited, and various known waxes can be used. Examples of waxes include low-molecular-weight polypropylene, polyethylene, polyolefins such as oxidized low-molecular-weight polypropylene and polyethylene, paraffin wax, synthetic ester wax, and the like. Among them, paraffin wax is preferably used from the viewpoint of improving the storage stability of the toner.

The content of the releasing agent is preferably 1 to 30% by mass, more preferably 3 to 15% by mass in the toner.

<Charge control agent>
The toner according to the present invention may contain a charge control agent. The charge control agent to be used is not particularly limited as long as it is a substance capable of imparting positive or negative charge by triboelectrification and is colorless. An electrostatic charge control agent can be used.

The content of the charge control agent is preferably 0.01 to 30% by mass, more preferably 0.1 to 10% by mass in the toner.

<External Additives>
In order to improve the fluidity, chargeability, cleanability, etc. of the toner, the toner according to the present invention is formed by adding external additives such as fluidizing agents, cleaning aids, etc., which are so-called post-treatment agents, to the toner particles. You may

Examples of external additives include inorganic oxide particles such as silica particles, alumina particles and titanium oxide particles, inorganic stearate compound particles such as aluminum stearate particles and zinc stearate particles, strontium titanate particles and zinc titanate particles. Inorganic particles such as inorganic titanate compound particles such as These can be used alone or in combination of two or more.

These inorganic particles may be surface-treated with a silane coupling agent, a titanium coupling agent, a higher fatty acid, a silicone oil, or the like, in order to improve heat-resistant storage stability and environmental stability.

The amount of these external additives added is preferably 0.05 to 5% by mass, more preferably 0.1 to 3% by mass in the toner.

<Average Particle Diameter of Toner>
The average particle diameter of the toner is preferably 4 to 20 μm, more preferably 5 to 15 μm, as a volume-based median diameter (D50). When the volume-based median diameter (D50) is within the above range, the transfer efficiency is high, the image quality of halftones is improved, and the image quality of fine lines and dots is improved.

The volume-based median diameter (D50) of the toner is obtained by a computer system (manufactured by Beckman Coulter, Inc.) equipped with "Software V3.51" for data processing in "Coulter Counter 3" (manufactured by Beckman Coulter, Inc.). can be measured and calculated using a measuring device connected to

Specifically, 0.02 g of the measurement sample (toner) was mixed with 20 mL of a surfactant solution (for example, a surfactant obtained by diluting a neutral detergent containing a surfactant component with pure water 10 times for the purpose of dispersing the toner particles). solution) and allowed to acclimatize, 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 concentration indicated by the measuring device reaches 8%.

Here, by setting the display density within the above range, reproducible measured values can be obtained. Then, in the measuring device, the measured particle count number is 25000, the aperture diameter is 50 μm, and the measurement range of 1 to 30 μm is divided into 256 to calculate the frequency value. The particle diameter of is defined as the volume-based median diameter (D50).

[Toner manufacturing method]
The method for producing the toner of the present invention is not particularly limited. For example, when the polymer compound represented by the above general formula (1) alone is used as a toner, the polymer compound represented by the general formula (1) is processed in a machine such as a hammer mill, feather mill, counter jet mill, or the like. and then classified to a desired particle size using a dry classifier such as a spin air sieve, a classifier, or a micron classifier.

When producing a toner containing the polymer compound represented by formula (1) and a colorant and not containing a binder resin, a solvent in which both the polymer compound represented by formula (1) and the colorant dissolve is used. is used to dissolve the polymer compound represented by the general formula (1) and the colorant to form a solution, then the solvent is removed, and then pulverized and classified in the same manner as described above. A method is preferred.

When a toner containing a polymer compound represented by formula (1), a binder resin, and optionally a colorant is produced, a production method using an emulsion aggregation method, which facilitates control of the particle size and shape, is used. Preferably.

Such a manufacturing method is
(1A) Binder resin particle dispersion preparing step for preparing a binder resin particle dispersion (1B) Polymer compound particle dispersion for preparing a dispersion of polymer compound particles represented by general formula (1) Preparation step (1C) If necessary, a colorant particle dispersion preparation step of preparing a colorant particle dispersion (2) Binder resin particles, polymer compound particles, and optionally colorant particles are present. (3) Toner particles are formed by controlling the shape of the associated particles by adding an aggregating agent to the water-based medium in which the salting out is progressed and at the same time performing aggregation and fusion to form associated particles. (4) Filtration and washing process for filtering toner particles from an aqueous medium and removing surfactants from the toner particles (5) Drying process for drying the washed toner particles (6) Drying process It is preferable to include each step of an external additive adding step of adding an external additive to the formed toner particles.

The steps (1A) to (1C) will be described below.

(1A) Binder Resin Particle Dispersion Preparation Step In this step, resin particles are formed by conventionally known emulsion polymerization or the like, and the resin particles are aggregated and fused to form binder resin particles. As an example, a polymerizable monomer constituting the binder resin is put into an aqueous medium and dispersed, and the polymerizable monomer is polymerized with a polymerization initiator to prepare a dispersion liquid of binder resin particles. .

As a method for obtaining a binder resin particle dispersion, in addition to the method of polymerizing a polymerizable monomer in an aqueous medium using a polymerization initiator, for example, dispersion treatment in an aqueous medium without using a solvent is performed. Alternatively, a method of dissolving the crystalline resin in a solvent such as ethyl acetate to form a solution, emulsifying and dispersing the solution in an aqueous medium using a dispersing machine, and then removing the solvent.

At this time, if necessary, the binder resin may contain a release agent in advance. In addition, for dispersion, polymerize in the presence of an appropriately known surfactant (e.g., anionic surfactants such as polyoxyethylene (2) sodium dodecyl ether sulfate, sodium dodecyl sulfate, dodecylbenzenesulfonic acid). is also preferred.

The volume-based median diameter of the binder resin particles in the dispersion is preferably 50 to 300 nm. The volume-based median diameter of the binder resin particles in the dispersion can be measured by a dynamic light scattering method using "Microtrac UPA-150" (manufactured by Nikkiso Co., Ltd.).

(1B) Polymer compound particle dispersion preparation step In this polymer compound particle dispersion preparation step, the polymer compound represented by the general formula (1) is dispersed in an aqueous medium in the form of fine particles, and the general formula ( 1) is a step of preparing a dispersion liquid of polymer compound particles.

In preparing a dispersion liquid of particles of the polymer compound represented by the general formula (1), first, an emulsified liquid of the polymer compound is prepared. The emulsified solution of the polymer compound can be produced, for example, by dissolving the polymer compound in an organic solvent and then emulsifying the resulting solution in an aqueous medium.

The method of dissolving the polymer compound in the organic solvent is not particularly limited, and examples thereof include a method of adding the polymer compound to the organic solvent and stirring and mixing so that the polymer compound is dissolved. The amount of the polymer compound added is preferably 5 parts by mass or more and 100 parts by mass or less, more preferably 10 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the organic solvent.

Next, the obtained solution of the polymer compound and the aqueous medium are mixed and stirred using a known dispersing machine such as a homogenizer. As a result, the polymer compound forms droplets and is emulsified in the aqueous medium to prepare an emulsified liquid of the polymer compound.

The amount of the polymer compound solution added is preferably 10 parts by mass or more and 120 parts by mass or less with respect to 100 parts by mass of the aqueous medium.

When the solution of the polymer compound and the aqueous medium are mixed, the temperature of the solution of the polymer compound and the temperature of the aqueous medium are in the temperature range below the boiling point of the organic solvent, and are preferably 20° C. or higher and 80° C. or lower. , more preferably 30°C or higher and 75°C or lower. When the polymer compound solution and the aqueous medium are mixed, the temperature of the polymer compound solution and the temperature of the aqueous medium may be the same or different, preferably the same.

As for the stirring conditions of the disperser, for example, when the volume of the stirring vessel is 1 to 3 L, the rotation speed is preferably 7000 rpm or more and 20000 rpm or less, and the stirring time is preferably 10 minutes or more and 30 minutes or less.

The dispersion of particles of the polymer compound is prepared by removing the organic solvent from the emulsion of the polymer compound. Examples of the method for removing the organic solvent from the emulsion of the polymer compound include known methods such as air blowing, heating, pressure reduction, or a combination thereof.

As an example, the emulsified liquid of the polymer compound is preferably 25° C. or higher and 90° C. or lower, more preferably 30° C. or higher and 80° C. or lower, under an inert gas atmosphere such as nitrogen, for example, at an initial organic solvent amount of The organic solvent is removed by heating until approximately 80% by mass or more and 95% by mass or less of is removed. As a result, the organic solvent is removed from the aqueous medium, and a dispersion liquid of the particles of the polymer compound in which the particles of the polymer compound are dispersed in the aqueous medium is prepared.

The mass average particle size of the polymer compound particles in the polymer compound particle dispersion is preferably 90 nm or more and 1200 nm or less. The mass average particle diameter is determined by the viscosity when the polymer compound is blended in an organic solvent, the mixing ratio of the polymer compound solution and the aqueous medium, and the dispersing machine used when preparing the emulsion of the polymer compound. It can be set within the above range by appropriately adjusting the stirring speed and the like. The mass average particle size of the polymer compound particles in the polymer compound particle dispersion liquid can be measured using an electrophoretic light scattering photometer "ELS-800" (manufactured by Otsuka Electronics Co., Ltd.). .

<Organic solvent>
The organic solvent used in this step is not particularly limited as long as it can dissolve the polymer compound represented by the general formula (1). Specifically, esters such as ethyl acetate and butyl acetate; ethers such as diethyl ether, diisopropyl ether and tetrahydrofuran; ketones such as acetone and methyl ethyl ketone; saturated hydrocarbons such as hexane and heptane; Examples include halogenated hydrocarbons such as chlorocarbons.

Such organic solvents can be used alone or in combination of two or more. Among these organic solvents, ketones and halogenated hydrocarbons are preferred, and methyl ethyl ketone and dichloromethane are more preferred.

<Aqueous medium>
Examples of the aqueous medium used in this step include water, or an aqueous medium containing water as a main component and water-soluble solvents such as alcohols and glycols, and optional ingredients such as surfactants and dispersants. be done. A mixture of water and a surfactant is preferably used as the aqueous medium.

Examples of surfactants include cationic surfactants, anionic surfactants, and nonionic surfactants. Examples of cationic surfactants include dodecyl ammonium chloride, dodecyl ammonium bromide, dodecyltrimethylammonium bromide, dodecylpyridinium chloride, dodecylpyridinium bromide, hexadecyltrimethylammonium bromide and the like. Examples of anionic surfactants include fatty acid soaps such as sodium stearate and sodium dodecanoate, sodium dodecylbenzenesulfonate, and sodium dodecylsulfate. Examples of nonionic surfactants include polyoxyethylene dodecyl ether, polyoxyethylene hexadecyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene dodecyl ether, polyoxyethylene sorbitan monooleate ether, monodecanoyl Sucrose etc. are mentioned.

Such surfactants can be used alone or in combination of two or more. Among surfactants, anionic surfactants, more preferably sodium dodecylbenzenesulfonate, are preferably used.

The amount of the surfactant added is preferably 0.01 to 10 parts by mass, more preferably 0.04 to 1 part by mass with respect to 100 parts by mass of the aqueous medium.

(1C) Colorant Particle Dispersion Preparation Step This colorant particle dispersion preparation step is a step of dispersing the colorant in the form of fine particles in an aqueous medium to prepare a colorant particle dispersion.

Dispersion of the colorant can be performed using mechanical energy. The number-based median diameter of the colorant particles in the dispersion is preferably 10 to 300 nm, more preferably 50 to 200 nm. The number-based median diameter of the colorant particles can be measured using an electrophoretic light scattering photometer "ELS-800" (manufactured by Otsuka Electronics Co., Ltd.).

The steps from (2) association step to (6) external additive addition step can be carried out according to various conventionally known methods.

Although the flocculant used in the (2) association step is not particularly limited, one selected from metal salts is preferably used. Examples of metal salts include monovalent metal salts such as salts of alkali metals such as sodium, potassium and lithium; divalent metal salts such as calcium, magnesium, manganese and copper; trivalent metal salts such as iron and aluminum. etc. Specific metal salts include sodium chloride, potassium chloride, lithium chloride, calcium chloride, magnesium chloride, zinc chloride, copper sulfate, magnesium sulfate, manganese sulfate, etc., of which less It is particularly preferred to use a divalent metal salt because it can promote These can be used alone or in combination of two or more.

[Developer]
For example, the toner according to the present invention may be used as a one-component magnetic toner containing a magnetic material, mixed with a so-called carrier and used as a two-component developer, or used as a non-magnetic toner alone. and any of them can be suitably used.

As the magnetic material, for example, magnetite, γ-hematite, or various ferrites can be used.

The carrier contained in the two-component developer includes magnetic particles made of conventionally known materials such as metals such as iron, steel, nickel, cobalt, ferrite and magnetite, and alloys of these metals with metals such as aluminum and lead. can be used.

The carrier may be a coated carrier in which the surfaces of magnetic particles are coated with a coating agent such as a resin, or a resin-dispersed carrier in which magnetic powder is dispersed in a binder resin. The coating resin is not particularly limited, but for example, olefin resin, acrylic resin, styrene resin, styrene-acrylic resin, silicone resin, polyester resin, fluorine resin, or the like is used. Moreover, the resin for constituting the resin-dispersed carrier particles is not particularly limited, and known resins can be used. can do.

The volume-based median diameter of the carrier is preferably 20 to 100 μm, more preferably 25 to 80 μm. The volume-based median diameter of the carrier can typically be measured by a laser diffraction particle size distribution analyzer "HELOS" (manufactured by SYMPATEC) equipped with a wet disperser.

The mixing amount of the toner with the carrier is preferably 2 to 10% by weight, with the total weight of the toner and the carrier being 100% by weight.

[Image forming method]
The toner of the present invention can be used in various known electrophotographic image forming methods. For example, it can be used for a monochrome image forming method and a full-color image forming method. In the full-color image forming method, there is a four-cycle image forming method configured by four types of color developing devices for yellow, magenta, cyan, and black, respectively, and one photoreceptor, and a color developing method for each color. The present invention can be applied to any image forming method such as a tandem image forming method in which an image forming unit having a device and a photoreceptor is mounted for each color.

That is, the image forming method according to one embodiment of the present invention includes the steps of: 1) forming a toner image made of the toner of the present invention on a recording medium; and 2) irradiating the toner image with light to form the toner image. and softening.

Step 1) In this step, a toner image made of the toner of the present invention is formed on a recording medium.

(recoding media)
A recording medium is a member for holding a toner image. Examples of recording media include coated printing paper such as plain paper, fine paper, art paper, and coated paper, commercially available Japanese paper and postcard paper, OHP or packaging resin film, and cloth. .

The recording medium may be in the form of a sheet (leaf) having a predetermined size, or may be in the form of a long sheet that is wound into a roll after the toner image is fixed.

The formation of the toner image can be carried out, for example, by transferring the toner image on the photosensitive member onto the recording medium, as will be described later.

Step 2) In this step, the formed toner image is irradiated with light to soften the toner image. As a result, the toner image can be adhered onto the recording medium.

The wavelength of the light to be irradiated is not particularly limited as long as the toner image can be sufficiently softened by photothermal conversion by the polymer compound in the toner. Within the above range, the toner image can be softened more efficiently. From the same point of view, the irradiation amount of light is preferably 0.1 to 200 J/cm ² , more preferably 0.1 to 100 J/cm ² , still more preferably 0.1 to 50 J/cm ² .

Light irradiation can be performed using a light source such as a light emitting diode (LED) or a laser light source, as described later.

After step 2), step 3) of pressing the softened toner image may be further carried out, if necessary.

Step 3) In this step, the softened toner image is pressed.

The pressure when pressing the toner image on the recording medium is not particularly limited, but is preferably 0.01 to 5.0 MPa, more preferably 0.05 to 1.0 MPa. By setting the pressure to 0.01 MPa or more, the amount of deformation of the toner image can be increased, so the contact area between the toner image and the recording paper S increases, and the fixability of the image can be further improved. Also, by setting the pressure to 5.0 MPa or less, shock noise during pressurization can be suppressed.

The pressing step may be performed before or at the same time as the step of applying light to soften the toner image (step 2) above). It is preferable because it can be pressed, and as a result, the fixability of the image is further improved.

Further, in the pressing step, the softened toner image may be further heated. That is, the pressing process may be performed while heating the toner image.

The heating temperature of the toner image (the surface temperature of the toner image during heating) is preferably (Tg+20) to (Tg+100)°C, where Tg is the glass transition temperature of the toner, and is (Tg+25) to (Tg+80)°C. is more preferable. When the surface temperature of the toner image is (Tg+20)° C. or higher, the toner image is easily deformed by pressure, and when it is (Tg+100)° C. or lower, hot offset is easily suppressed. Note that hot offset refers to a phenomenon in which a part of the toner is transferred to a pressure member such as a roller in the fixing process, and the toner layer is divided.

In addition, before the step 2), the step 4) of heating the toner image in advance may be further performed if necessary. As described above, the sensitivity of the polymer compound of the present invention to light can be further increased by further performing the step 4) of heating the toner image in advance before the step of 2). As a result, even if it is a polymer, the sensitivity to light is less likely to be impaired, and the melting or softening of the toner image by light irradiation is facilitated.

The image forming method of the present invention can be performed by using, for example, the following image forming apparatus.

FIG. 1 is a schematic configuration diagram showing an image forming apparatus 100 used in an image forming method according to an embodiment of the invention. However, the image forming apparatus used in the present invention is not limited to the following forms and illustrated examples. Although FIG. 1 shows an example of a monochrome image forming apparatus 100, the present invention can also be applied to a color image forming apparatus.

The image forming apparatus 100 is an apparatus for forming an image on a recording sheet S as a recording medium,
Equipped with an image reading device 71 and an automatic document feeder 72 , the image forming section 10 , the irradiation section 40 and the pressing section 9 form an image on the recording paper S transported by the paper transport system 7 .

Further, although the image forming apparatus 100 uses the recording paper S as a recording medium, the medium on which the image is formed may be other than the paper.

The document d placed on the document table of the automatic document feeder 72 is scanned and exposed by the optical system of the scanning exposure device of the image reading device 71 and read into the image sensor CCD. An analog signal photoelectrically converted by the image sensor CCD is subjected to analog processing, A/D conversion, shading correction, image compression processing, etc. in the image processing section 20, and then input to the exposure device 3 of the image forming section 10. be.

The paper transport system 7 includes a plurality of trays 16, a plurality of paper feed units 11, transport rollers 12, a transport belt 13, and the like. Each tray 16 accommodates recording paper S of a predetermined size, and the paper feeding unit 11 of the tray 16 determined according to an instruction from the control unit 90 is operated to supply the recording paper S. FIG. The transport roller 12 transports the recording paper S sent out from the tray 16 by the paper feeding unit 11 or the recording paper S carried in from the manual paper feeding unit 15 to the image forming unit 10 .

The image forming unit 10 includes a charger 2 , an exposure unit 3 , a developing unit 4 , a transfer unit 5 and a cleaning unit 8 arranged in this order around the photoreceptor 1 along the rotational direction of the photoreceptor 1 . It is

A photoreceptor 1, which is an image carrier, is an image carrier having a photoconductive layer formed on its surface, and is configured to be rotatable in the direction of the arrow in FIG. 1 by a driving device (not shown). A thermo-hygrometer 17 for detecting temperature and humidity in the image forming apparatus 100 is provided near the photoreceptor 1 .

The charger 2 uniformly charges the surface of the photoreceptor 1 to uniformly charge the surface of the photoreceptor 1 . The exposure unit 3 has a beam light source such as a laser diode, and irradiates the charged surface of the photoreceptor 1 with a beam light to eliminate the electric charge on the irradiated portion, thereby forming a static image on the photoreceptor 1 according to the image data. Forms an electrostatic latent image. The developing unit 4 supplies toner contained therein to the photoreceptor 1 to form a toner image based on an electrostatic latent image on the surface of the photoreceptor 1 .

The transfer unit 5 faces the photoreceptor 1 with the recording paper S interposed therebetween, and transfers the toner image onto the recording paper S. As shown in FIG. The cleaning section 8 has a blade 85 . The blade 85 cleans the surface of the photoreceptor 1 to remove the developer remaining on the surface of the photoreceptor 1 .

The recording paper S onto which the toner image has been transferred is conveyed to the pressure bonding section 9 by the conveying belt 13 . The pressure-bonding unit 9 is optionally installed, and applies pressure alone or heat and pressure to the recording paper S to which the toner image has been transferred by the pressure members 91 and 92, thereby performing a fixing process, thereby recording. The image is fixed on the paper S. The recording paper S on which the image has been fixed is transported to the paper discharge section 14 by the transport roller, and is discharged from the paper discharge section 14 to the outside of the apparatus.

In addition, the image forming apparatus 100 includes a paper reversing unit 24, and the recording paper S subjected to the heat fixing process is conveyed to the paper reversing unit 24 before the paper discharging unit 14, and then reversed and discharged. Alternatively, the recording paper S whose front and back sides have been reversed is conveyed to the image forming section 10 again, and images can be formed on both sides of the recording paper S. FIG.

<Irradiation part>
FIG. 2 is a schematic configuration diagram of the irradiation unit 40 in the image forming apparatus 100. As shown in FIG.

An image forming apparatus 100 according to one embodiment of the present invention includes an irradiation section 40 . The irradiation unit 40 irradiates the toner image formed on the recording paper S with light. Examples of devices that constitute the irradiation unit 40 include light emitting diodes (LEDs) and laser light sources.

The irradiation unit 40 irradiates light toward the first surface of the recording paper S holding the toner image on the photosensitive member side. It is arranged on the photoreceptor side with respect to the

The irradiation unit 40 is arranged downstream of the nip position between the photoreceptor 1 and the transfer unit 5 in the sheet conveying direction and upstream of the pressing unit 9 in the sheet conveying direction.

According to the image forming method according to one embodiment of the present invention, after charging the photoreceptor 1 by applying a uniform potential to the photoreceptor 1 by the charger 2, the photoreceptor 1 is exposed with a light beam irradiated by the exposure device 3 based on the original image data. It scans over the body 1 and forms an electrostatic latent image. Next, the developer containing the toner of the present invention is supplied onto the photosensitive member 1 by the developing section 4 .

When the toner image carried on the surface of the photoreceptor 1 reaches the position of the transfer unit 5 due to the rotation of the photoreceptor 1 , the recording paper S is conveyed from the tray 16 to the image forming unit 10 , and transferred to the transfer unit 5 . The toner image on the photoreceptor 1 is transferred onto the recording paper S nipped between the transfer portion 5 and the photoreceptor 1 by the applied transfer bias.

The transfer unit 5 also serves as a pressure member, and can transfer the toner image from the photoreceptor 1 to the recording paper S while ensuring that the polymer compound contained in the toner image adheres firmly to the recording paper S. can be made

After the toner image is transferred onto the recording paper S, the blade 85 of the cleaning section 8 removes the developer remaining on the surface of the photoreceptor 1 .

While the recording paper S having the toner image transferred thereon is conveyed to the pressing unit 9 by the conveying belt 13 , the irradiation unit 40 irradiates the toner image transferred onto the recording paper S with light. By irradiating the toner image on the first surface of the recording paper S with light from the irradiation unit 40, the toner image can be melted more reliably, and the fixability of the toner image to the recording paper S can be improved. can be done.

When the recording sheet S carrying the toner image reaches the pressing section 9 by the conveying belt 13 , the pressing members 91 and 92 press the toner image onto the first surface of the recording sheet S. As shown in FIG. Since the toner image is softened by light irradiation from the irradiating unit 40 before the fixing process is performed by the pressing unit 9, energy saving for pressing the image onto the recording sheet S can be achieved.

The pressure when pressing the toner image is as described above. The pressing step may be performed before, at the same time as, or after the step of softening the toner image by irradiating light. From the viewpoint of being able to apply pressure to the toner image that has been softened in advance and to easily increase the image strength, it is preferable that the application of pressure is performed after the light irradiation.

Further, the pressure member 91 can heat the toner image on the recording paper S when the recording paper S passes between the pressure members 91 and 92 . The toner image softened by the light irradiation is further softened by this heating, and as a result, the fixability of the toner image to the recording paper S is further improved.

The heating temperature of the toner image is as described above. The heating temperature of the toner image (the surface temperature of the toner image) can be measured with a non-contact temperature sensor. Specifically, for example, a non-contact temperature sensor may be installed at a position where the recording medium is discharged from the pressure member to measure the surface temperature of the toner image on the recording medium.

The toner image pressed by the pressing members 91 and 92 is solidified and fixed on the recording sheet S. As shown in FIG.

EXAMPLES The present invention will be specifically described below with reference to Examples, but the present invention is not limited to these.

[Synthesis of Polymer 1]
<Synthesis of azobenzene derivative monomer 1>
In a 300 ml three-head Kolben, 6.44 g (0.933 mol) of sodium nitrite was dissolved in 20 ml of water and cooled to an internal temperature of 0°C. To this, 5 g (0.047 mol) of p-toluidine and 23 g of 0.2N hydrochloric acid aqueous solution were slowly added dropwise at an internal temperature of 5° C. or lower. After dropping, the mixture was stirred for 30 minutes while maintaining the internal temperature.

A solution obtained by dissolving 5.71 g (0.06 mol) of phenol, 2.43 g (0.06 mol) of sodium hydroxide and 6.43 g (0.06 mol) of sodium carbonate in 20 ml of water was added to the resulting solution. It was slowly added dropwise while maintaining the temperature below °C to precipitate yellow crystals. After completion of dropping, the mixture was stirred for 30 minutes while maintaining the internal temperature, filtered and washed with cold water to obtain orange crystals. After drying it, it was purified with a silica gel column (ethyl acetate/heptane=1/4) to obtain 9.7 g (yield 97.9%) of the desired product 1 (4-(p-toluyldiazenyl) phenol) was obtained.

5 g (0.024 mol) of the obtained target product 1 (4-(p-toluyldiazenyl)phenol) was dissolved in 25 ml of dimethylformamide (DMF) in a 200 ml four-head Kolben. To this, 4.88 g (0.035 mol) of potassium carbonate was added, and the mixture was stirred for 30 minutes while maintaining the temperature at 30°C. To this, 10.2 mg (0.06 mmol) of potassium iodide and 3.54 g (0.026 mol) of 6-chloro-1-hexanol were added and reacted at 110° C. for 3 hours. It was cooled to room temperature, added to 650 g of ice and filtered. The crystals were dispersed in 400 ml of water, washed with stirring overnight, filtered and dried.

Recrystallization was performed with ethanol to obtain 6.41 g (yield 87.1%) of target product 2 (6-(4-(p-tolylazenyl)phenoxy)hexan-1-ol) as orange crystals. .

3 g (0.001 mol) of the obtained target product 2 (6-(4-(p-tolylazenyl)phenoxy)hexan-1-ol), 1.34 ml (0.001 mol) of triethylamine and dichloromethane were placed in a 100 ml four-headed flask. 30 ml was added. At this time, the raw material was in a dispersed state. While maintaining the internal temperature at 0°C, a solution of 1.04 g (0.011 mol) of acrylic acid chloride dissolved in 10 ml of dichloromethane was added dropwise while maintaining the internal temperature at 0 to 5°C. As it was dripped, the raw material dissolved.

After completion of dropping, the reaction solution was returned to room temperature and stirred for 5 hours. After completion of the reaction, dichloromethane was removed by concentration, dissolved in ethyl acetate, washed with dilute hydrochloric acid, aqueous sodium hydrogencarbonate solution and saturated brine, and the organic layer was dried over magnesium sulfate and then concentrated. The resulting orange crystals were purified with a silica gel column (ethyl acetate/heptane=1/5) to obtain 2.87 g (yield 51.4%) of azobenzene derivative monomer 1.

<Synthesis of macroinitiator 1>
In a 100 ml eggplant flask, 230 mg (1.47 mmol) of 2,2′-bipyridyl was added, and further Cu(I)Br 95 mg (0.66 mmol), styrene 15 g (144 mmol), 2-bromoiso 35 mg (0.18 mmol) of ethyl butyrate was added and sealed. This was heated and stirred in an oil bath at 100°C. After that, an appropriate amount of tetrahydrofuran was added and passed through a neutral alumina column. This was reprecipitated with methanol and centrifuged for purification to obtain macroinitiator 1. The number average molecular weight (B Mn) of the obtained macroinitiator 1 was 1,500 when measured by the GPC method.

<Synthesis of polymer 1>
In a 100 ml eggplant flask, 15 g (41 mmol) of the azobenzene derivative monomer obtained above and 47 mg (0.18 mol) of the macroinitiator 1 were added, and 29 mg of Cu(I)Cl ( 0.29 mmol), 136 mg (0.59 mmol) of 1,1,4,7,10,10-hexamethyltriethylenetetramine, and 4.9 g (41.1 mmol) of anisole as a solvent were added and sealed. Then, the mixture was heated and stirred in an oil bath at 80°C. After that, an appropriate amount of chloroform was added and passed through a basic alumina column. The polymer was purified by reprecipitation with methanol and centrifugation to obtain a polymer 1. The total number average molecular weight Mn of the obtained polymer 1 was 3,500 when measured by the GPC method.

[Synthesis of polymer 2]
<Synthesis of macroinitiator 2>
Macroinitiator 2 was obtained in the same manner as in <Synthesis of macroinitiator 1>, except that ethyl 2-bromoisobutyrate was changed to an equimolar amount of α,α'-dibromo-p-xylene.

<Synthesis of polymer 2>
Polymer 2 was obtained in the same manner as in <Synthesis of Polymer 1>, except that macroinitiator 1 was changed to macroinitiator 2.

[Synthesis of polymer 3]
<Synthesis of macroinitiator 3>
In <Synthesis of macroinitiator 1>, ethyl 2-bromoisobutyrate was changed to ethylene bis(2-bromoisobutyrate), and 2,2′-bipyridyl was changed to 1,1,4, Macroinitiator 3 was obtained in the same manner except that 7,10,10-hexamethyltriethylenetetramine was used, styrene was changed to azobenzene derivative monomer 1, and anisole was added.

<Synthesis of polymer 3>
In <Synthesis of polymer 1>, macroinitiator 1 is changed to macroinitiator 3, 1,1,4,7,10,10-hexamethyltriethylenetetramine is changed to 2,2′-bipyridyl, Polymer 3 was obtained in the same manner except that azobenzene derivative monomer 1 was changed to styrene and anisole was removed.

[Synthesis of Polymer 4]
<Synthesis of macroinitiator 4>
<Synthesis of macroinitiator 1> Macroinitiator 4 was obtained in the same manner except that ethyl 2-bromoisobutyrate was changed to 1,1,1-tris(2-bromoisobutyryloxymethyl)ethane. rice field.

<Synthesis of Polymer 4>
Polymer 4 was obtained in the same manner as in <Synthesis of Polymer 1>, except that macroinitiator 1 was changed to macroinitiator 4.

[Synthesis of polymer 5]
<Synthesis of macroinitiator 5>
In <Synthesis of macroinitiator 3>, ethylene bis(2-bromoisobutyrate) was changed to 1,1,1-tris(2-bromoisobutyryloxymethyl)ethane. obtained macroinitiator 5 in a similar manner.

<Synthesis of Polymer 5>
Polymer 5 was obtained in the same manner as in <Synthesis of Polymer 3> except that macroinitiator 3 was changed to macroinitiator 5.

[Synthesis of polymer 6]
<Synthesis of macroinitiator 6>
Macroinitiator 6 was obtained in the same manner as in <Synthesis of macroinitiator 1>, except that ethyl 2-bromoisobutyrate was changed to pentaerythritol tetrakis(2-bromoisobutyrate).

<Synthesis of polymer 6>
Polymer 6 was obtained in the same manner as in <Synthesis of Polymer 1> except that macroinitiator 1 was changed to macroinitiator 6.

[Synthesis of polymer 7]
<Synthesis of macroinitiator 7>
Macroinitiator 7 was obtained in the same manner as in <Synthesis of macroinitiator 3>, except that ethylenebis(2-bromoisobutyric acid) was changed to pentaerythritoltetrakis(2-bromoisobutyrate).

<Synthesis of Polymer 7>
Polymer 7 was obtained in the same manner as in <Synthesis of Polymer 3>, except that macroinitiator 3 was changed to macroinitiator 7.

[Synthesis of Polymer 8]
<Synthesis of azobenzene derivative monomer 2>
Azobenzene derivative monomer 2 was obtained in the same manner as for azobenzene derivative monomer 1 except that acrylic acid chloride was changed to methacrylic acid chloride in <Synthesis of azobenzene derivative monomer 1>.

<Synthesis of polymer 8>
Polymer 8 was obtained in the same manner as in <Synthesis of polymer 2>, except that azobenzene derivative monomer 1 was changed to azobenzene derivative monomer 2.

[Synthesis of Polymer 9]
<Synthesis of azobenzene derivative monomer 3>
In <Synthesis of azobenzene derivative monomer 1>, azobenzene derivative monomer 3 was prepared in the same manner as for azobenzene derivative monomer 1, except that phenol was changed to 6-phenyl-1-hexanol and the synthesis for obtaining target product 2 was eliminated. Obtained.

<Synthesis of polymer 9>
Polymer 9 was obtained in the same manner as in <Synthesis of polymer 2>, except that azobenzene derivative monomer 1 was changed to azobenzene derivative monomer 3.

[Synthesis of polymer 10]
<Synthesis of azobenzene derivative 4 monomers>
Azobenzene derivative monomer 4 was obtained in the same manner as for azobenzene derivative monomer 1 except that 6-chloro-1-hexanol was changed to 6-chloro-1-octanol in <Synthesis of azobenzene derivative monomer 1>.

<Synthesis of polymer 10>
Polymer 10 was obtained in the same manner as in <Synthesis of Polymer 2> except that azobenzene derivative monomer 1 was changed to azobenzene derivative monomer 4.

[Synthesis of Polymer 11]
<Synthesis of azobenzene derivative monomer 5>
Azobenzene derivative monomer 5 was obtained in the same manner as for azobenzene derivative monomer 1 except that p-toluidine was changed to 3-aminophenol and phenol was changed to toluene in <Synthesis of azobenzene derivative monomer 1>.

<Synthesis of polymer 11>
Polymer 11 was obtained in the same manner as in <Synthesis of polymer 2>, except that azobenzene derivative monomer 1 was changed to azobenzene derivative monomer 5.

[Synthesis of polymer 12]
<Synthesis of azobenzene derivative monomer 6>
Azobenzene derivative monomer 6 was obtained in the same manner as for azobenzene derivative monomer 1 except that p-toluidine was changed to 2-aminophenol and phenol was changed to toluene in <Synthesis of azobenzene derivative monomer 1>.

<Synthesis of polymer 12>
Polymer 12 was obtained in the same manner as in <Synthesis of Polymer 2>, except that azobenzene derivative monomer 1 was changed to azobenzene derivative monomer 6.

[Synthesis of Polymer 13]
<Synthesis of azobenzene derivative monomer 7>
Azobenzene derivative monomer 7 was obtained in the same manner as for azobenzene derivative monomer 1 except that phenol was changed to o-cresol in <Synthesis of azobenzene derivative monomer 1>.

<Synthesis of polymer 13>
Polymer 13 was obtained in the same manner as in <Synthesis of polymer 2>, except that azobenzene derivative monomer 1 was changed to azobenzene derivative monomer 7.

[Synthesis of Polymer 14]
<Synthesis of azobenzene derivative monomer 8>
Azobenzene derivative monomer 8 was obtained in the same manner as for azobenzene derivative monomer 1 except that p-toluidine was changed to m-toluidine in <Synthesis of azobenzene derivative monomer 1>.

<Synthesis of Polymer 14>
Polymer 14 was obtained in the same manner as in <Synthesis of polymer 2> except that azobenzene derivative monomer 1 was changed to azobenzene derivative monomer 8.

[Synthesis of Polymer 15]
<Synthesis of azobenzene derivative monomer 9>
Azobenzene derivative monomer 9 was obtained in the same manner as for azobenzene derivative monomer 1 except that p-toluidine was changed to o-toluidine in <Synthesis of azobenzene derivative monomer 1>.

<Synthesis of polymer 15>
Polymer 15 was obtained in the same manner as in <Synthesis of Polymer 2>, except that azobenzene derivative monomer 1 was changed to azobenzene derivative monomer 9.

[Synthesis of Polymer 16]
<Synthesis of azobenzene derivative monomer 10>
Azobenzene derivative monomer 10 was obtained in the same manner as for azobenzene derivative monomer 1 except that p-toluidine was changed to aniline in <Synthesis of azobenzene derivative monomer 1>.

<Synthesis of Polymer 16>
Polymer 16 was obtained in the same manner as in <Synthesis of polymer 2> except that azobenzene derivative monomer 1 was changed to azobenzene derivative monomer 10.

[Synthesis of Polymer 17]
<Synthesis of azobenzene derivative monomer 11>
Azobenzene derivative monomer 11 was obtained in the same manner as for azobenzene derivative monomer 1 except that p-toluidine was changed to 4-ethylaniline in <Synthesis of azobenzene derivative monomer 1>.

<Synthesis of polymer 17>
Polymer 17 was obtained in the same manner as in <Synthesis of polymer 2> except that azobenzene derivative monomer 1 was changed to azobenzene derivative monomer 11.

[Synthesis of polymer 18]
<Synthesis of azobenzene derivative monomer 12>
Azobenzene derivative monomer 12 was obtained in the same manner as for azobenzene derivative monomer 1 except that p-toluidine was changed to 4-hexylaniline in <Synthesis of azobenzene derivative monomer 1>.

<Synthesis of polymer 18>
Polymer 18 was obtained in the same manner as in <Synthesis of Polymer 2> except that azobenzene derivative monomer 1 was changed to azobenzene derivative monomer 12.

[Synthesis of polymer 19]
<Synthesis of azobenzene derivative monomer 13>
Azobenzene derivative monomer 13 was obtained in the same manner as for azobenzene derivative monomer 1 except that p-toluidine was changed to 4-methoxyaniline in <Synthesis of azobenzene derivative monomer 1>.

<Synthesis of Polymer 19>
Polymer 19 was obtained in the same manner as in <Synthesis of Polymer 2>, except that azobenzene derivative monomer 1 was changed to azobenzene derivative monomer 13.

[Synthesis of polymer 20]
<Synthesis of azobenzene derivative monomer 14>
Azobenzene derivative monomer 14 was obtained in the same manner as for azobenzene derivative monomer 1 except that p-toluidine was changed to 4-nitroaniline in <Synthesis of azobenzene derivative monomer 1>.

<Synthesis of Polymer 20>
Polymer 20 was obtained in the same manner as in <Synthesis of Polymer 2>, except that azobenzene derivative monomer 1 was changed to azobenzene derivative monomer 14.

[Synthesis of Polymer 21]
<Synthesis of azobenzene derivative monomer 15>
Azobenzene derivative monomer 15 was obtained in the same manner as for azobenzene derivative monomer 1 except that p-toluidine was changed to 4′-aminoacetophenone in <Synthesis of azobenzene derivative monomer 1>.

<Synthesis of polymer 21>
Polymer 21 was obtained in the same manner as in <Synthesis of Polymer 2> except that azobenzene derivative monomer 1 was changed to azobenzene derivative monomer 15.

[Synthesis of polymer 22]
<Synthesis of azobenzene derivative monomer 16>
Azobenzene derivative monomer 16 was obtained in the same manner as for azobenzene derivative monomer 1 except that p-toluidine was changed to methyl 4-aminobenzoate in <Synthesis of azobenzene derivative monomer 1>.

<Synthesis of polymer 22>
Polymer 22 was obtained in the same manner as in <Synthesis of Polymer 2>, except that azobenzene derivative monomer 1 was changed to azobenzene derivative monomer 16.

[Synthesis of polymer 23]
<Synthesis of azobenzene derivative monomer 17>
Azobenzene derivative monomer 17 was obtained in the same manner as for azobenzene derivative monomer 1 except that p-toluidine was changed to 3-methyl-4-hexylaniline in <Synthesis of azobenzene derivative monomer 1>.

<Synthesis of polymer 23>
Polymer 23 was obtained in the same manner as in <Synthesis of Polymer 2>, except that azobenzene derivative monomer 1 was changed to azobenzene derivative monomer 17.

[Synthesis of polymer 24]
<Synthesis of macroinitiator 8>
Macroinitiator 8 was obtained in the same manner as in <Synthesis of macroinitiator 2>, except that styrene was changed to n-butyl acrylate.

<Synthesis of polymer 24>
Polymer 24 was obtained in the same manner as in <Synthesis of Polymer 1>, except that macroinitiator 1 was changed to macroinitiator 8.

[Synthesis of Polymer 25]
<Synthesis of macroinitiator 9>
Macroinitiator 9 was obtained in the same manner as in <Synthesis of macroinitiator 2>, except that styrene was changed to n-butyl methacrylate.

<Synthesis of polymer 25>
Polymer 25 was obtained in the same manner as in <Synthesis of Polymer 1>, except that macroinitiator 1 was changed to macroinitiator 9.

[Synthesis of polymer 26]
<Synthesis of macroinitiator 10>
Macroinitiator 10 was obtained in the same manner as in <Synthesis of macroinitiator 2>, except that styrene was changed to 1-pentene.

<Synthesis of Polymer 26>
Polymer 26 was obtained in the same manner as in <Synthesis of Polymer 1>, except that macroinitiator 1 was changed to macroinitiator 10.

[Synthesis of polymer 27]
<Synthesis of macroinitiator 11>
Macroinitiator 11 was obtained in the same manner as in <Synthesis of macroinitiator 2>, except that styrene was changed to a mixture of styrene and n-butyl acrylate in a molar ratio of 5:5.

<Synthesis of Polymer 27>
Polymer 27 was obtained in the same manner as in <Synthesis of Polymer 1>, except that macroinitiator 1 was changed to macroinitiator 11.

The structures and number average molecular weights (total number average molecular weight, polymer block A number average molecular weight, polymer block B number average molecular weight) of the obtained polymers 1 to 27 are shown in Table 1. In Table 1, polymer block A contains a structural unit derived from a compound represented by the following formula (2), and in formula (2), any one of X ₁ to X ₃ is a polymerizable group and the group Y having the polymerizable group is a group represented by (ii) or (iii) below.

<Comparative compound>
The following comparative compound 1 (number average molecular weight Mn: 2870) was obtained by the method described in paragraphs "0217" to "0227" of JP-A-2014-191078.

The total number average molecular weight of Polymers 1 to 27 obtained above, the number average molecular weight of the macroinitiator and the number average molecular weight of Comparative Compound 1 were measured by the following methods. Further, the number average molecular weight of the macroinitiator is taken as the number average molecular weight of polymer block A or B, and (the number average molecular weight of the macroinitiator x the number of blocks) is subtracted from the total number average molecular weight of the polymer for each block structure. The total number average molecular weight of the other polymer block (number average molecular weight of the other polymer block x number of blocks) was obtained. The results are shown in Table 1 below. In Table 1, Mn represents the total number average molecular weight of the polymer, A Mn represents the total number average molecular weight of polymer block A, and B Mn represents the total number average molecular weight of polymer block B, respectively.

(Number average molecular weight Mn)
The number average molecular weights Mn of Polymers 1 to 27 and Comparative Compound 1 were measured by the GPC method. Specifically, using an apparatus "HLC-8120GPC" (manufactured by Tosoh Corporation) and a column "TSKguardcolumn + TSKgelSuperHZ-M triplet" (manufactured by Tosoh Corporation), while maintaining the column temperature at 40 ° C., tetrahydrofuran (THF) as a carrier solvent ) was flowed at a flow rate of 0.2 mL/min. The measurement sample was dissolved in tetrahydrofuran to a concentration of 1 mg/ml. The solution was prepared by processing at room temperature for 5 minutes using an ultrasonic disperser. Then, it was treated with a membrane filter having a pore size of 0.2 μm to obtain a sample solution, and 10 μL of this sample solution was injected into the apparatus together with the above carrier solvent and detected using a refractive index detector (RI detector). The molecular weight distribution of the measurement sample was calculated based on a calibration curve prepared using monodisperse polystyrene standard particles. Ten points of polystyrene were used for the calibration curve measurement.

The glass transition temperature (Tg) of the polymer obtained above was measured by the following method.

(Glass transition temperature (Tg))
The glass transition temperature (Tg) of the polymer was measured with DSC7000X manufactured by Hitachi High-Tech Science. Specifically, about 3 mg of the polymer was accurately weighed to two decimal places, sealed in an aluminum pan, and set. An empty aluminum pan was used as a reference. A first heating process in which the temperature is raised from 0 ° C. to 200 ° C. at a temperature increase rate of 10 ° C./min; a cooling process in which the temperature is lowered from 200 ° C. to 0 ° C. at a temperature decrease rate of 10 ° C./min; and a temperature increase rate of 10 ° C./min. A second heating process in which the temperature is raised from 0° C. to 200° C. per minute was set as the measurement condition in this order. Then, an analysis was performed based on the data in the second heating process. The glass transition temperature was defined as the intersection point between the extension of the baseline before the rise of the first endothermic peak and the tangential line indicating the maximum slope from the rise of the first endothermic peak to the apex of the peak.

The glass transition temperature (Tg) of Polymer 2 obtained above was 58.9°C.

[Preparation of Toner]
[Preparation of Toner 1]
Polymer 1 was coarsely pulverized with a hammer mill to a particle size of 1 mm or less, and then finely pulverized with a collision-type pneumatic pulverizer using high-pressure gas to obtain a pulverized material. Next, the fine powder and the coarse powder were simultaneously classified and removed using a Kraseal (high-efficiency precision air classifier, manufactured by Seishin Enterprise Co., Ltd.) to obtain toner base particles.

1% by mass of hydrophobic silica (number-average primary particle size: 12 nm) and 0.3% by mass of hydrophobic titania (number-average primary particle size: 20 nm) were added to the obtained toner base particles, and a Henschel mixer (registered Toner 1 was obtained by blending with a trademark).

[Preparation of toners 2 to 27]
Toners 2 to 27 were obtained in the same manner as toner 1, except that polymer 1 was changed to polymers 2 to 27, respectively.

[Preparation of Toner 28]
<Preparation of Polymer Particle Dispersion Liquid 1>
80 parts by mass of dichloromethane and 20 parts by mass of polymer 2 prepared above were mixed and stirred while heating at 50° C. to obtain a solution containing polymer 2 . A mixture of 99.5 parts by mass of distilled water warmed to 50° C. and 0.5 parts by mass of a 20% by mass sodium dodecylbenzenesulfonate aqueous solution was added to 100 parts by mass of the obtained solution. Thereafter, the mixture was emulsified by stirring at 16000 rpm for 20 minutes using a homogenizer (manufactured by Heidolf Co.) equipped with a shaft generator 18F, and an emulsion of polymer 2 was obtained.

The resulting emulsified liquid was put into a separable flask, and the organic solvent was removed by heating and stirring at 40° C. for 90 minutes while supplying nitrogen into the gas phase to obtain a polymer particle dispersion liquid 1. When the particle size of the polymer particles in the polymer particle dispersion 1 was measured using an electrophoretic light scattering photometer "ELS-800" (manufactured by Otsuka Electronics Co., Ltd.), the mass average particle size was 189 nm. .

<Preparation of styrene acrylic resin particle dispersion>
(First stage polymerization)
A reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introduction device was charged with a solution of 8 parts by mass of sodium dodecyl sulfate dissolved in 3000 parts by mass of ion-exchanged water, and stirred at a stirring speed of 230 rpm under a nitrogen stream. while increasing the internal temperature to 80°C. After raising the temperature, a solution obtained by dissolving 10 parts by mass of potassium persulfate in 200 parts by mass of ion-exchanged water was added, and the liquid temperature was raised to 80° C. again. 0 parts by weight of n-octyl-3-mercaptopropionate and 16.0 parts by weight of n-octyl-3-mercaptopropionate was added dropwise over 1 hour, followed by heating and stirring at 80°C for 2 hours for polymerization. to prepare a styrene-acrylic resin particle dispersion (1A) containing the styrene-acrylic resin particles (1a).

(Second-stage polymerization)
A reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introduction device was charged with a solution of 7 parts by mass of polyoxyethylene (2) sodium dodecyl ether sulfate dissolved in 800 parts by mass of ion-exchanged water, and heated to 98°C. 260 parts by mass of the styrene acrylic resin particle dispersion (1A) obtained above, 245 parts by mass of styrene, 120 parts by mass of n-butyl acrylate, and 1.5 parts by mass of n-octyl-3-mercaptopropionate. , Add a polymerizable monomer solution obtained by dissolving 67 parts by mass of paraffin wax "HNP-11" (manufactured by Nippon Seiro Co., Ltd.) as a release agent at 90 ° C., and a mechanical disperser having a circulation path. The mixture was mixed and dispersed for 1 hour using "CREARMIX (registered trademark)" (manufactured by M Technic Co., Ltd.) to prepare a dispersion containing emulsified particles (oil droplets). Next, an initiator solution prepared by dissolving 6 parts by mass of potassium persulfate in 200 parts by mass of ion-exchanged water is added to the dispersion, and the system is heated and stirred at 82° C. for 1 hour to carry out polymerization. A styrene-acrylic resin particle dispersion (1B) containing styrene-acrylic resin particles (1b) was prepared.

(Third stage polymerization)
A solution of 11 parts by mass of potassium persulfate dissolved in 400 parts by mass of ion-exchanged water was added to the resulting styrene-acrylic resin particle dispersion (1B), and then 435 parts by mass of styrene was added at a temperature of 82°C. , 130 parts by mass of n-butyl acrylate, 33 parts by mass of methacrylic acid and 8 parts by mass of n-octyl-3-mercaptopropionate was added dropwise over 1 hour. After completion of the dropwise addition, the mixture was heated and stirred for 2 hours for polymerization, and then cooled to 28° C. to obtain a styrene-acrylic resin particle dispersion liquid 1 containing styrene-acrylic resin 1. Moreover, when the glass transition temperature (Tg) of the styrene acrylic resin 1 was measured, it was 45°C.

<Production of Toner 28>
576 parts by mass of polymer particle dispersion liquid 1 prepared above in terms of solid content, 144 parts by mass of styrene acrylic resin particle dispersion liquid 1 in terms of solid content (polymer: styrene acrylic resin = 80:20 mass ratio), and 900 parts by mass of ion-exchanged water was put into a reactor equipped with a stirrer, a temperature sensor, and a cooling pipe. The temperature inside the container was kept at 30° C., and the pH was adjusted to 10 by adding a 5 mol/liter sodium hydroxide aqueous solution.

Next, an aqueous solution obtained by dissolving 2 parts by mass of magnesium chloride hexahydrate in 1000 parts by mass of ion-exchanged water was added dropwise over 10 minutes while stirring. C., and the particle growth reaction was continued while maintaining the temperature at 70.degree. In this state, the particle size of the associated particles was measured using "Multisizer 3" (manufactured by Beckman Coulter, Inc.). was dissolved in 760 parts by mass of ion-exchanged water to stop grain growth. After stirring at 70° C. for 1 hour, the temperature was further increased and the mixture was heated and stirred at 75° C. to promote fusion of the particles. Thereafter, by cooling to 30° C., a dispersion liquid of toner base particles was obtained.

The dispersion liquid of the obtained toner base particles was subjected to solid-liquid separation with a centrifuge to form a wet cake of the toner base particles. The wet cake is washed with ion-exchanged water at 35°C in a centrifuge until the electric conductivity of the filtrate reaches 5 μS/cm, and then transferred to a “flash jet dryer (manufactured by Seishin Enterprise Co., Ltd.)”, and the water content is It was dried to 0.5% by mass to prepare toner base particles.

1% by mass of hydrophobic silica (number-average primary particle size: 12 nm) and 0.3% by mass of hydrophobic titania (number-average primary particle size: 20 nm) were added to the obtained toner base particles, and a Henschel mixer (registered Toner 28 was obtained by mixing with a trademark).

[Preparation of Toner 29]
<Preparation of polyester resin particle dispersion liquid 1>
A 10-liter four-necked flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple was charged with 524 parts by mass of a bisphenol A propylene oxide 2 mol adduct, 105 parts by mass of terephthalic acid, 69 parts by mass of fumaric acid, and 2 parts by mass of tin octylate (esterification catalyst) were added, and a polycondensation reaction was carried out at a temperature of 230° C. for 8 hours. Furthermore, after continuing the polycondensation reaction at 8 kPa for 1 hour, the mixture was cooled to 160° C. to obtain a polyester resin 1. 100 parts by mass of the polyester resin 1 was pulverized with "Randel Mill type: RM" (manufactured by Tokuju Kosakusho Co., Ltd.), mixed with 638 parts by mass of a 0.26% by mass sodium dodecyl sulfate aqueous solution prepared in advance, and superimposed while stirring. Ultrasonic dispersion was performed for 30 minutes at V-LEVEL and 300 μA using a sonic homogenizer “US-150T” (manufactured by Nippon Seiki Seisakusho Co., Ltd.) to obtain a polyester resin particle dispersion liquid 1. Moreover, when the glass transition temperature (Tg) of polyester resin 1 was measured, it was 42°C.

<Production of Toner 29>
Toner 29 was prepared in the same manner as in <Preparation of Toner 28> except that the styrene acrylic resin particle dispersion 1 was changed to the polyester resin particle dispersion 1.

[Preparation of Toner 30]
Toner 30 was prepared in the same manner as in <Preparation of Toner 1>, except that Comparative Compound 1 was used instead of Polymer 1.

[Preparation of Toner 31]
<Preparation of Comparative Compound Dispersion>
Comparative compound dispersion was obtained in the same manner as in <Preparation of polymer particle dispersion 1>, except that polymer 2 was changed to comparative compound 1.

<Preparation of Toner 31>
Toner 31 was prepared in the same manner as in <Preparation of Toner 28> except that Polymer Particle Dispersion 1 was changed to Comparative Compound Dispersion.

[Production of developer]
For toners 1 to 31 prepared above, ferrite carrier particles having a volume average particle diameter of 30 μm coated with a copolymer resin of cyclohexane methacrylate and methyl methacrylate (monomer mass ratio of 1:1) were added to the toner particles at a toner particle concentration of 6% by mass. Developing agents 1 to 31 were obtained. Mixing was performed for 30 minutes using a V-blender.

[Evaluation: fixability test]
The fixability test was conducted using Developers 1 to 31 obtained above under normal temperature and normal humidity environment (temperature 20° C., humidity 50% RH). The developer is placed between a pair of parallel flat plate (aluminum) electrodes having a developer on one side and a gloss coated paper (grammage: 128 g/m ² ) as a recording medium on the other side while the developer is slid by magnetic force. The toner was developed under the conditions that the gap was 0.5 mm and the amount of toner adhered to the DC and AC biases was 4 g/m ² to form a toner layer on the surface of the gloss coated paper, which was fixed by each fixing device. I used a printout. A 1 cm square toner image of this printed matter was rubbed 10 times with JK Wiper (registered trademark) (manufactured by Nippon Paper Crecia Co., Ltd.) under a pressure of 35 kPa to evaluate the fixation rate of the image. A fixation rate of 70% or more was regarded as acceptable. The image fixation rate is defined by measuring the reflection density of the image after printing and the image after rubbing with a fluorescence spectrodensitometer "FD-7" (manufactured by Konica Minolta, Inc.), and the solid image after rubbing. is a value obtained by dividing the reflection density of the printed solid image by the reflection density of the solid image after printing and expressed as a percentage.

As the fixing device, the following three types of fixing devices configured by appropriately modifying the device shown in FIG. 2 were used.

No. 1: Without the crimping part 9 in FIG. 2, the wavelength of the ultraviolet light emitted from the irradiation part 40 is 365 nm (light source: LED light source with an emission wavelength of 365 nm ± 10 nm), and the irradiation amount is 12 J / cm ² ;
No. 2: There is the crimping part 9 of FIG. The light source and irradiation amount of the irradiation unit 40 are No. is similar to 1;
No. 3: There is the crimping portion 9 of FIG. 2, the temperature of the pressing member 91 is 80° C., and the pressure during pressing is 0.2 MPa. The light source and irradiation amount of the irradiation unit 40 are No. Same as 1.

Tables 1 and 2 below show the composition of each toner, the type of fixing device, and the evaluation results.

As shown in Tables 1 and 2, toners having polymers 1 to 27 which are block copolymers having a polymer block A containing a structural unit derived from an azobenzene derivative and a polymer block B of a thermoplastic resin. In Examples 1 to 31 using , an excellent fixation rate of 70% or more is exhibited in a toner image fixability test. On the other hand, in Comparative Examples 1 and 2, in which the toner containing no polymer is used, sufficient fixability cannot be obtained when the fixing method by light irradiation is used.

Among them, from the comparison of Examples 1 to 7, it was found that a toner image can be obtained by using a polymer having a structure of ABA (2A-B) or a polymer having a structure of BAB (A-2B). The fixing rate of is further improved.

As the polymerizable group, good results were obtained when a group having any of the polymerizable groups (ii) and (iii) was introduced. The fixing rate of the toner image is further improved (compare Examples 2 and 9).

Good results were obtained when the group having a polymerizable group was introduced at _any position of X ₁ , X ₂ and X ₃ in formula (2). When it is introduced, the fixation rate of toner images is further improved (comparison with Examples 2, 11, and 12).

In addition to the above, it is particularly preferred that the azobenzene derivative satisfies formula (4) (compare Examples 2, 16-19 with Examples 13-15, 20-23).

Further, from the results of Examples 2 and 16 to 19, in formula (4), R ₃ is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 8 carbon atoms. Although good results can be obtained in Examples 2 and 16, the total number average molecular weight of polymer block A, the total number average molecular weight of polymer block B, and the total number average molecular weight of the polymer are all within predetermined ranges. , 18 and 19 tended to be more excellent in fixability.

Moreover, not only the polymer but also the binder resin can be added to the toner (Examples 28 and 29). It was confirmed that a good fixing rate was similarly obtained when a binder resin was further used. By using the above polymer, a good fixing rate can be obtained even if the content of the binder resin is small.

Moreover, in Examples 30 and 31, which further include the step of pressing the toner image softened by light irradiation, and in Example 31, in which the softened toner image is further heated in the step of pressing, the fixability is further improved.

1 photoreceptor,
2 charger,
3 exposure device,
4 developing section,
5 transfer unit,
7 paper transport system,
8 cleaning section,
9 crimping part,
10 image forming unit,
11 paper feeding unit,
12 transport rollers,
13 conveyor belts,
14 paper ejection section,
15 manual feed unit,
16 trays,
17 thermo-hygrometer,
20 image processing unit,
24 paper reversing section,
40 irradiation unit,
71 image reader,
72 automatic document feeder,
85 blades,
90 control unit,
91, 92 pressure member,
100 image forming apparatus,
d manuscript,
S Recording paper.

Claims (11)

A toner containing a polymer compound represented by the following general formula (1):

In the above general formula (1), A is a polymer block containing a structural unit derived from an azobenzene derivative having a polymerizable group, B is a polymer block that is a thermoplastic resin having no azobenzene group,
The azobenzene derivative having a polymerizable group contains a group represented by any one of the following formulas (i) to (iii) as a group having a polymerizable group:

In formulas (i) to (iii) above, each R ₁ is independently a hydrogen atom or a methyl group, and each R ₂ is independently an alkylene group having 1 to 18 carbon atoms. The toner according to claim 1 , wherein the azobenzene derivative having a polymerizable group is represented by the following formula (2):

In the above formula (2), any one of X ₁ to X ₃ is a group having the polymerizable group, the rest are hydrogen atoms, and R ₃ to R ₅ are each independently hydrogen atom, halogen group, nitro group, hydroxy group, carboxy group, alkyl group having 1 to 16 carbon atoms, alkoxy group having 1 to 16 carbon atoms, acyl group having 2 to 16 carbon atoms, 2 to 2 carbon atoms 16 alkoxycarbonyl groups or acyloxy groups having 2 to 16 carbon atoms. 3. The toner according to claim 2 , wherein the azobenzene derivative is represented by the following formula (3):

In formula (3), X ₁ is a group having the polymerizable group, R ₃ is a hydrogen atom, a halogen group, a nitro group, a hydroxy group, a carboxy group, an alkyl group having 1 to 16 carbon atoms, a carbon It is an alkoxy group having 1 to 16 atoms, an acyl group having 2 to 16 carbon atoms, an alkoxycarbonyl group having 2 to 16 carbon atoms, or an acyloxy group having 2 to 16 carbon atoms. 4. The toner according to claim 3 , wherein the azobenzene derivative is represented by the following formula (4):

In formula (4), R ₁ is a hydrogen atom or a methyl group, R ₂ is an alkylene group having 1 to 18 carbon atoms, and R ₃ is a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. , or an alkoxy group having 1 to 8 carbon atoms. The total number average molecular weight of the polymer blocks A contained in the polymer compound represented by the general formula (1) is 1000 or more, the total number average molecular weight of the polymer blocks B is 1000 or more, and the general 5. The toner according to any one of claims 1 to 4 , wherein the polymer compound represented by formula (1) has a total number average molecular weight of 3500 or more. The toner according to any one of claims 1 to 5 , wherein the polymer block B is a polymer block containing at least one structural unit derived from a styrene derivative, (meth)acrylic acid derivative, or olefin derivative. The toner according to any one of claims 1 to 6 , further comprising a binder resin. forming a toner image made of the toner according to any one of claims 1 to 7 on a recording medium;
and irradiating the toner image with light to soften the toner image. 9. The image forming method according to claim 8 , wherein the wavelength of said light is 280 nm or more and 480 nm or less. 10. The image forming method according to claim 8 , further comprising pressing the softened toner image. 11. The image forming method according to claim 10 , wherein the softened toner image is further heated in the pressing step.

Images