JP6446929B2 - Image forming method, toner set and white toner - Google Patents

Description

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

  In the image forming method using the electrophotographic method, the image forming body is uniformly charged by the charging unit, and then image exposure is performed to form an electrostatic latent image. The latent image portion is developed by subsequent developing means to form a toner image. In recent years, development in response to various demands from the market has been made in the field of electrostatic latent image toner used for electrophotographic image formation. In particular, the types of recording media to be printed are increasing, and the demand for the recording media compatibility of printing presses is very high.

  For example, when outputting to a special recording medium such as colored paper, black paper, aluminum vapor-deposited paper, or transparent film, only full-color toner consisting of four colors of yellow, magenta, cyan, and black is affected by the color characteristics of the recording medium. However, sufficient color development cannot be obtained. Therefore, it has been proposed to use white toner as the lowermost layer as the fifth color (for example, Patent Document 1).

  By forming a white toner image, it is possible to conceal the color of the recording medium and to suppress image disturbance due to the irregularities on the surface of the recording medium.

JP 2006-220694 A

  However, the conventional method has a problem that the color developability cannot be sufficiently satisfied.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming method for improving color developability, and a toner set and white toner used therefor.

  A step of forming an image forming layer (A) on a recording medium using a white toner; an image forming layer (adjacent to the image forming layer (A) using a toner different from the white toner) B) forming step; and fixing the image forming layer (A) and the image forming layer (B). An image forming method comprising: forming a binder resin contained in the white toner The total amount of the linear aliphatic dicarboxylic acid and the linear aliphatic diol constituting the binder resin contained in the toner different from the white toner, where Tw is the total amount of the linear aliphatic dicarboxylic acid and the linear aliphatic diol. Where Tc is the following formula (1):

The above-described problems are solved by providing an image forming method that satisfies the above.

  A toner set comprising a white toner and a toner different from the white toner used in the image forming layer (B) adjacent to the image forming layer (A) obtained by using the white toner, wherein the white toner The total amount of linear aliphatic dicarboxylic acid and linear aliphatic diol constituting the binder resin contained in the toner is Tw, and the linear aliphatic dicarboxylic acid constituting the binder resin contained in the toner different from the white toner When the total amount of the acid and the linear aliphatic diol is Tc, the following formula (1):

The above-described problems are solved by providing a toner set that satisfies the above.

  Further, in the relationship between the white toner used for the image forming layer (B) adjacent to the image forming layer (A) obtained using the white toner and a different toner, the binder resin included in the white toner is configured. The total amount of the linear aliphatic dicarboxylic acid and the linear aliphatic diol constituting the binder resin contained in the toner different from the white toner is Tw, where the total amount of the linear aliphatic dicarboxylic acid and the linear aliphatic diol is Tw. When Tc, the following formula (1):

The above problem is solved by providing a white toner that satisfies the above requirements.

  According to the present invention, it is possible to provide an image forming method for improving color developability, and a toner set and white toner used therefor.

  In the first embodiment of the present invention, the step of forming an image forming layer (A) on a recording medium using a white toner; and the step of forming the image forming layer (A) using a toner different from the white toner An image forming method comprising: forming an image forming layer (B) adjacent to each other; and fixing the image forming layer (A) and the image forming layer (B). The total amount of linear aliphatic dicarboxylic acid and linear aliphatic diol constituting the binder resin contained in the toner is Tw, and the linear aliphatic dicarboxylic acid constituting the binder resin contained in the toner different from the white toner When the total amount of the acid and the linear aliphatic diol is Tc, the following formula (1):

This is an image forming method that satisfies the above.

  The second embodiment of the present invention is a toner comprising a white toner and a toner different from the white toner used in the image forming layer (B) adjacent to the image forming layer (A) obtained by using the white toner. A total amount of linear aliphatic dicarboxylic acid and linear aliphatic diol constituting the binder resin contained in the white toner is Tw, and the binder resin contained in a toner different from the white toner When the total amount of the linear aliphatic dicarboxylic acid and the linear aliphatic diol is Tc, the following formula (1):

It is a toner set that satisfies the above.

  Note that the toner set here refers to a combination of toners that form different image forming layers when transferred onto a recording medium. Therefore, for example, a combination of white toner and black toner that forms a gray image by packing black toner and white toner in one toner bottle is not included in the toner set.

  The third embodiment of the present invention includes the white toner in relation to the white toner different from the white toner used in the image forming layer (B) adjacent to the image forming layer (A) obtained by using the white toner. The total amount of the linear aliphatic dicarboxylic acid and the linear aliphatic diol constituting the binder resin is Tw, and the linear aliphatic dicarboxylic acid and the direct acid constituting the binder resin contained in a toner different from the white toner are used. When the total amount of the chain aliphatic diol is Tc, the following formula (1):

A white toner satisfying

  Here, the “white toner” includes at least a binder resin and a white colorant. Furthermore, other additives such as a release agent and external additives may be included as necessary.

  In addition, the “toner different from the white toner” may be referred to as “other toner”, and as a representative example, it may be referred to as “color toner” (“color toner” will be described later). .

  Regarding the second embodiment of the present invention and the third embodiment of the present invention, the description of the first embodiment of the present invention can be similarly applied. Therefore, the following description will focus on the first embodiment of the present invention.

  The “other toner” is not particularly limited as long as it is other than a white toner, and is a colored toner or a transparent toner (consisting of at least a binder resin and no colorant. Further, if necessary. Release additives and other additives and external additives), metallic color (including at least a binder resin and a metallic pigment, and if necessary, other additives such as release agents and external additives) A fluorescent toner (including at least a binder resin and a fluorescent pigment, and may further include other additives such as a release agent and external additives as necessary), near-infrared absorption. Toner (including at least a binder resin and a near-infrared absorbing pigment, and may further include other additives such as a release agent and external additives as necessary).

  Here, the “color toner” includes at least a binder resin and a colorant other than white. Colored means a color other than white (for example, yellow, magenta, cyan, black, etc.).

  The “image forming layer” refers to a toner image formed by transferring toner onto a recording medium, and refers to a toner image before fixing on the recording medium. Here, the layer order is preferably the order of the recording medium, the image forming layer (A) formed with white toner, and the image forming layer (B) formed with other toner. At this time, at the time of fixing by the fixing roller, the image forming layer (B) is on the fixing roller side. In the image forming apparatus, when there are two or more “other toners”, generally, all the toners can be the toner constituting the image forming layer (B).

  Here, the other toners are preferably colored toners from the viewpoint of improving color developability.

  Further, in the present specification, the term “toner” may mean one or both of “white toner” and “other toner”.

  As described above, when outputting to a special recording medium such as colored paper, black paper, aluminum vapor-deposited paper, transparent film, etc., the color characteristics of the recording medium influence the four colors of yellow, magenta, cyan, and black. Since sufficient color development cannot be obtained with the full color toner alone, it has been proposed to use a white toner for the lowermost layer as a new fifth color. By forming a white toner image, it is possible to conceal the color of the recording medium and to suppress image disturbance due to the irregularities on the surface of the recording medium. However, the conventional method has a problem that the color developability cannot be sufficiently satisfied.

  The present inventors diligently investigated the cause of insufficient color development. In the process, attention was paid to the relationship between the image forming layer (A) and the image forming layer (B).

  When white toner is used for the image forming layer (A) and a colored toner layer (image forming layer (B)) is formed on the white toner layer (image forming layer (A)), the heat of the fixing machine is increased. The toner of the upper layer (image forming layer (B)) that is directly received is more likely to be melted because heat is transferred first. At this time, if the toner in the lower layer is not sufficiently melted, the toner in the upper layer (image forming layer (B)) previously melted soaks into the lower layer (image forming layer (A)), and each layer is mixed in color. The present inventors thought whether there was.

  In the case of a general full-color image, the color developability is improved by mixing the upper layer toner and the lower layer toner. However, when the lower layer is a white toner, the mixed white pigment inhibits the absorption of the colored pigment, and the color developability is lowered. Therefore, it was considered that it is preferable not to mix the colors.

  Accordingly, the present inventors have conceived of controlling the difference in thermal response speed between the white toner and the colored toner in order to solve the problem. It was also found that the difference in thermal response speed between the white toner and the colored toner can be controlled by controlling the content of the linear aliphatic dicarboxylic acid and the linear aliphatic diol in the toner. More specifically, the white toner contains a larger amount of linear aliphatic dicarboxylic acid and linear aliphatic diol as a constituent component of the binder resin, thereby facilitating the formation of a crystal structure and having a melting point at the time of fixing. By rapidly plasticizing the binder resin (binder) of the white toner in the vicinity and quickly melting it, it is possible to suppress color mixing with the colored toner in the upper layer and to obtain an image with high color development. I found it.

  On the other hand, in order to prevent color mixing of each layer, a method of using a fixing machine twice is also conceivable. However, according to the present invention, since the toner can be fixed without using a fixing machine twice, it can be said that it is an epoch-making invention in that there is no troublesome fixing.

  Hereinafter, the configuration requirements will be described in detail.

(Binder resin)
In the present invention, the total amount of linear aliphatic dicarboxylic acid and linear aliphatic diol constituting the binder resin contained in the white toner is Tw, and the binder resin contained in the toner different from the white toner is constituted. , When the total amount of the linear aliphatic dicarboxylic acid and the linear aliphatic diol is Tc,
Following formula (1):

Meet.

  Speaking flatly, in the present invention, the binder resin constituting the white toner contains a linear aliphatic dicarboxylic acid and a linear aliphatic diol as essential raw materials, while the binder resins constituting other toners are also: Although linear aliphatic dicarboxylic acid and linear aliphatic diol may be included as raw materials, the total amount thereof is the total amount of linear aliphatic dicarboxylic acid and linear aliphatic diol constituting the binder resin contained in the white toner. Is less than “Other toners” may be used in combination of two or more. In this case, among the “other toners”, the total amount of “linear aliphatic dicarboxylic acid and linear aliphatic diol” constitutes the binder resin contained in the white toner. It may be less than the total amount of aliphatic diol.

  In the present invention, the above formula (1) may be satisfied. From the viewpoint of color development, the following formula (2):

It is preferable to satisfy.

  Similarly, from the viewpoint of color developability, the following formula (3):

It is preferable to satisfy.

  Here, as long as the relationship of the above formula (1) is satisfied, the binder resin of at least one of the white toner and the other toner can include conventionally known resins, for example, styrene such as polyvinyltoluene and its substitution Polymer: styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-acrylic Ethyl acid copolymer, Styrene-butyl acrylate copolymer, Styrene-octyl acrylate copolymer, Styrene-methyl methacrylate copolymer, Styrene-ethyl methacrylate copolymer, Styrene-butyl methacrylate copolymer Styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile Copolymer, Styrene-vinyl methyl ketone copolymer, Styrene-butadiene copolymer, Styrene-isoprene copolymer, Styrene-acrylonitrile-indene copolymer, Styrene-maleic acid copolymer, Styrene-maleic acid ester copolymer Styrene copolymers such as polymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, polyacrylic acid resin, rosin , Modified rosin, terpene resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin.

  However, from the viewpoint of color developability, it is preferable that at least one binder resin of the white toner and the other toner contains a crystalline polyester resin on the assumption that the relationship of the above formula (1) is satisfied. More preferably, both other toners contain a crystalline polyester resin.

When both the white toner and the other toner contain a crystalline polyester resin, the content of the crystalline polyester contained in the binder resin constituting the white toner is Tw ′, and a toner different from the white toner is constituted. When the content of the crystalline polyester contained in the binding resin and Tc ′,
Following formula (4)

It is preferable to satisfy By satisfying such a relationship, the color developability is improved.

  Here, the crystalline polyester will be described.

<Crystalline polyester resin>
The crystalline polyester resin is a differential scanning calorimetry (DSC) among polyester resins obtained by a polycondensation reaction of a divalent or higher carboxylic acid (polyvalent carboxylic acid) and a divalent or higher alcohol (polyhydric alcohol). ) Refers to a resin having a clear endothermic peak rather than a stepwise endothermic change. The clear endothermic peak specifically means a peak in which the half-value width of the endothermic peak is within 15 ° C. when measured at a rate of temperature increase of 10 ° C./min in differential scanning calorimetry (DSC). To do.

  The weight average molecular weight (Mw) of the crystalline polyester resin is preferably 2,000 to 20,000. Within such a range, the resulting toner does not have a low melting point as a whole, and has excellent blocking resistance and excellent low-temperature fixability.

  The melting point (Tm) of the crystalline polyester resin is preferably 50 to 120 ° C, and more preferably 60 to 90 ° C. It is preferable that the melting point of the crystalline polyester resin is in the above range since low temperature fixability and fixability can be appropriately obtained. The melting point of the crystalline polyester resin is defined as the endothermic peak temperature measured by the method described in the examples as the melting point of the crystalline polyester resin.

  The acid value (AV) of the crystalline polyester resin is preferably 5 to 70 mgKOH / g.

  The crystalline polyester resin can be generated from a polyvalent carboxylic acid component and a polyhydric alcohol component as described above. The valence of the polyvalent carboxylic acid component and the polyhydric alcohol component is preferably 2 to 3, respectively. Hereinafter, a case where the valence is 2 as a preferable form (that is, a dicarboxylic acid component and a diol component) will be described.

[Dicarboxylic acid component]
As the dicarboxylic acid component, it is preferable that the binder resin constituting the white toner essentially includes a linear type, and the binder resins constituting other toners preferably include a linear type.

  As the linear aliphatic dicarboxylic acid, the number of carbon atoms constituting the main chain is preferably 2 to 22, except for the carbon of the carboxylic acid.

  Here, the “linear aliphatic dicarboxylic acid” in the present specification is a saturated fatty acid, but it is not limited to those containing no branched chain at all. May be included. When the branched chain is considered to be a substituent for the main chain, examples of the substituent include a methyl group and an ethyl group.

  Examples of the linear aliphatic dicarboxylic acid include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 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-octadecanedicarboxylic acid and the like can be mentioned, and lower alkyl esters and acid anhydrides thereof can also be used. In addition, as long as the relationship of the said Formula (1) is satisfy | filled, trivalent or more polyvalent carboxylic acid may be included. However, from the viewpoint of decreasing the crystallinity, it is better not to use a trivalent or higher polyvalent carboxylic acid as a raw material for the crystalline polyester resin.

  Among the above linear aliphatic dicarboxylic acids, the number of carbon atoms is preferably 4 to 14 from the viewpoint of decreasing crystallinity, and specifically, succinic acid, glutaric acid, adipic acid, pimelic acid, Suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid (dodecanedioic acid), and 1,12-dodecanedicarboxylic acid are preferred. A particularly preferred number of carbon atoms is 5 or more.

  The dicarboxylic acid component may contain an aromatic dicarboxylic acid as long as the relationship of the above formula (1) is satisfied. For example, terephthalic acid, isophthalic acid, orthophthalic acid, t-butylisophthalic acid, 2,6-naphthalene Examples thereof include dicarboxylic acid and 4,4′-biphenyldicarboxylic acid. Among these, terephthalic acid, isophthalic acid, and t-butylisophthalic acid are preferably used from the viewpoints of availability and emulsification ease.

  The amount of linear aliphatic dicarboxylic acid used is preferably 80 constituent mol% or more when the entire dicarboxylic acid component for forming the crystalline resin (crystalline polyester resin) is 100 constituent mol%, More preferably, it is 90 constituent mol% or more, More preferably, it is 100 constituent mol%. When the amount of the linear aliphatic dicarboxylic acid used is 80 constituent mol% or more, the crystallinity of the crystalline polyester resin can be ensured and excellent low-temperature fixability can be obtained in the produced toner. In addition, glossiness can be obtained in the formed image and deterioration of image storability due to melting point depression is suppressed, and when oil droplets are formed using an oil phase liquid containing the crystalline polyester resin, it is ensured. An emulsified state can be obtained.

  In addition, a dicarboxylic acid component may be used individually by 1 type, and may be used 2 or more types.

[Diol component]
As the diol component, it is preferable that the binder resin constituting the white toner essentially includes a linear type, and the binder resins constituting other toners preferably include a linear type. Each of them may contain a diol other than the linear aliphatic diol as necessary.

  As the linear aliphatic diol component, the number of carbon atoms constituting the main chain is preferably 2 to 22. Here, the “linear aliphatic diol” in the present specification is a saturated fatty acid, but not only one that does not contain any branched chain, but partly includes a branched chain within the scope of the effects of the present invention. It may be included. When the branched chain is considered to be a substituent for the main chain, examples of the substituent include a methyl group and an ethyl group.

  Examples of the linear aliphatic diol include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1, 8-octanediol, 1,9-nonanediol, 1,10-dodecanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1, Examples thereof include 18-octadecanediol and 1,20-eicosanediol.

  Among the above linear aliphatic diols, the number of carbon atoms is preferably 2 to 14, more preferably 4 to 12, more specifically, from the viewpoint of decreasing crystallinity. , Ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9- Nonanediol, 1,10-decanediol, and 1,12-dodecanediol are preferred.

  In addition, as long as the relationship of the said Formula (1) is satisfy | filled as a diol component, you may contain aromatic diol.

  As the diol component, a branched aliphatic diol can also be used on the assumption that the relationship of the formula (1) is satisfied as described above. In this case, it is preferable to use it together with a linear aliphatic diol and to increase the proportion of the linear aliphatic diol. By using the linear aliphatic diol in such a high proportion, it is possible to reliably obtain excellent low-temperature fixability in a toner manufactured with ensured crystallinity, and finally form an image. In this case, a decrease in image storability due to a decrease in melting point is suppressed, and further, blocking resistance can be reliably obtained.

  In addition, a diol component may be used individually by 1 type and may be used 2 or more types.

  As the diol component for forming the crystalline polyester resin, the content of the linear aliphatic diol is preferably 80 constituent mol% or more, more preferably 90 constituent mol% or more, and still more preferably 100 Constituent mol%. When the content of the linear aliphatic diol in the diol component is 80 constituent mol% or more, the crystallinity of the crystalline polyester resin can be ensured, and excellent low-temperature fixability can be obtained for the produced toner. At the same time, glossiness is obtained in the finally formed image.

  Examples of diols other than linear aliphatic diols include diols having a sulfonic acid group.

  In addition, as long as the relationship of the above formula (1) is satisfied, a monovalent acid such as acetic acid or benzoic acid, cyclohexanol, benzyl alcohol, etc. Trivalent alcohols such as divalent alcohols, benzenetricarboxylic acid, naphthalenetricarboxylic acid, etc., and anhydrides thereof, lower alkyl esters thereof, glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol can be used in combination.

  The crystalline resin (crystalline polyester resin) can be synthesized by any combination of the above-described constituent components using a conventionally known method. The transesterification method or the direct polycondensation method can be used alone, or It can be used in combination.

  Specifically, it can carry out at superposition | polymerization temperature 140-270 degreeC, and may raise superposition | polymerization temperature on the way as needed. If necessary, the reaction system is evacuated and the reaction is carried out while removing water and alcohol generated during the condensation. The reaction time is not particularly limited. When the monomer is not dissolved or compatible at the reaction temperature, a solvent having a high boiling point may be added as a solubilizing solvent and dissolved. In the polycondensation reaction, the dissolution auxiliary solvent is distilled off. In the case where a monomer having poor compatibility exists in the copolymerization reaction, it is preferable that the monomer having poor compatibility and the monomer and the acid or alcohol to be polycondensed are condensed in advance and then polycondensed together with the main component.

  The use ratio of the diol component to the dicarboxylic acid component is such that the equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] of the diol component to the carboxyl group [COOH] of the dicarboxylic acid component is 1.5 / 1. It is preferable to be set to ˜1 / 1.5, and more preferably 1.2 / 1 to 1 / 1.2. When the use ratio of the diol component and the dicarboxylic acid component is in the above range, a crystalline polyester resin having a desired molecular weight can be obtained with certainty.

  Catalysts that can be used in the production of crystalline polyester resins include titanium acetate, titanium propionate, titanium hexanoate, titanium octanoate and other aliphatic monocarboxylic acid titanium, titanium oxalate, titanium succinate, titanium maleate, Aliphatic titanium dicarboxylates such as titanium adipate and titanium sebacate, titanium aliphatic tricarboxylates such as titanium hexanetricarboxylate and isooctanetricarboxylic acid, titanium aliphatic polycarboxylates such as titanium octanetetracarboxylate and titanium decanetetracarboxylate , Titanium monocarboxylic acid such as titanium benzoate, titanium phthalate, titanium terephthalate, titanium isophthalate, titanium naphthalenedicarboxylate, titanium biphenyldicarboxylate, anthracenedical Aromatic dicarboxylic acid titanium such as titanium oxide; aromatic tricarboxylic acid titanium such as titanium trimellitic acid and titanium naphthalenetricarboxylate; aromatic tetracarboxylic acid titanium such as benzenetetracarboxylic acid titanium and naphthalenetetracarboxylic acid titanium; Titanium aromatic carboxylates, titanium titanates of aliphatic carboxylates and titanium aromatic carboxylates and alkali metal salts thereof, titanium halides such as dichlorotitanium, trichlorotitanium, tetrachlorotitanium, tetrabromotitanium, Tetraalkoxy titanium such as tetrabutoxy titanium (titanium tetrabutoxide), tetraoctoxy titanium, tetrastearyloxy titanium, titanium acetylacetonate, titanium diisopropoxide bisacetylacetonate, Tan triethanolaminate, titanium-containing catalysts, such as.

  The content (T′w) of the crystalline polyester resin with respect to the whole white toner is preferably 7 to 40% by mass, more preferably 7 to 30% by mass, and even more preferably 7 to 25% by mass. When the addition amount of the crystalline polyester resin is 40% by mass or less with respect to the whole white toner, occurrence of burying or filming of the external additive is small. Further, when it is 7% by mass or more, the color developability is improved.

  The content (T′c) of the crystalline polyester resin with respect to the entire other toner is preferably more than 0% by mass and less than 10% by mass, more preferably 2% by mass or more and less than 10% by mass, and further preferably 4% by mass or more. It is less than 10% by mass. By including the crystalline polyester resin, the effect of improving the low-temperature fixability can be effectively obtained.

  The “content of the crystalline polyester resin” will also be described later.

  In this specification, “whole toner” means the total mass of components (for example, binder resin, release agent, colorant, and external additive) constituting the toner. In addition, even if it is a component used at the stage of producing the toner, a component that is substantially not contained in the produced toner is not included in the “component constituting the toner” mentioned here. For example, such components include an aggregating agent, a surfactant, a polymerization initiator, and a catalyst. “Substantially free” means that the content of the component in the toner is 0.1% by mass. It means the following.

<Amorphous resin>
The amorphous resin is not particularly limited, but is preferably an amorphous polyester resin obtained by condensing a polyhydric alcohol component and a polyvalent carboxylic acid component.

  The amorphous polyester resin is a polyester resin other than the crystalline polyester resin. That is, it usually has no melting point and has a relatively high glass transition temperature (Tg). More specifically, the glass transition temperature (Tg) is preferably 40 to 90 ° C, and particularly preferably 42 to 80 ° C. The glass transition temperature (Tg) is measured by the method described in the examples.

  The weight average molecular weight (Mw) of the amorphous resin is preferably 3,000 to 100,000, more preferably 4,000 to 70,000. When the weight average molecular weight (Mw) of the amorphous resin is within such a range, the obtained toner has excellent blocking resistance and low temperature fixability.

  The polyhydric alcohol component is not particularly limited, and examples thereof include bisphenols such as bisphenol A and bisphenol F, and alkylene oxide adducts of bisphenols such as ethylene oxide adducts and propylene oxide adducts. Examples of the trihydric or higher polyhydric alcohol component include glycerin, trimethylolpropane, pentaerythritol, and sorbitol. Thus, the use of an alkylene oxide adduct of bisphenols as the raw material for the amorphous resin is preferable from the viewpoint of chargeability and toner strength.

  However, “linear aliphatic diol” described above may be included as a raw material, and cyclohexane dimethanol, cyclohexane diol, neopentyl alcohol, etc. may be used from the viewpoint of production cost and environmental properties. Further, as polyhydric alcohol components capable of forming an amorphous polyester resin, unsaturated polyhydric alcohols such as 2-butyne-1,4 diol, 3-butyne-1,4 diol, and 9-octadezene-7,12 diol Etc. can also be used.

  These polyhydric alcohol components may be used alone or in combination of two or more.

  The divalent carboxylic acid component to be condensed with the polyhydric alcohol component may be appropriately selected from the above-mentioned “linear aliphatic dicarboxylic acid”, or may be fumaric acid, maleic acid, alkenyl succinic acid, or the like. It may be an unsaturated aliphatic carboxylic acid or an aliphatic carboxylic acid anhydride such as maleic anhydride or alkenyl succinic anhydride. Alternatively, aromatic carboxylic acids such as terephthalic acid, isophthalic acid, phthalic anhydride, and naphthalenedicarboxylic acid may be used. Also, alicyclic carboxylic acids such as cyclohexanedicarboxylic acid may be used. Further, lower alkyl esters and acid anhydrides of these acids may be used, or one or more of these may be used.

  Use of fumaric acid is preferable from the viewpoints of chargeability and ease of emulsification.

  The use of alkenyl succinic acid or its anhydride is preferred in that it can be more easily compatible with the crystalline polyester resin due to the presence of alkenyl groups having higher hydrophobicity than other functional groups. Examples of alkenyl succinic acid components include n-dodecyl succinic acid, dodecenyl succinic acid hydrate, n-dodecenyl succinic acid, isododecyl succinic acid, isododecenyl succinic acid, n-octyl succinic acid, n-octenyl succinic acid, and these And acid anhydrides, acid chlorides and lower alkyl esters having 1 to 3 carbon atoms.

  The use of terephthalic acid is preferable from the viewpoints of chargeability and toner strength.

  Furthermore, by containing a trivalent or higher carboxylic acid, the polymer chain can take a crosslinked structure, and by taking the crosslinked structure, a decrease in elastic modulus on the high temperature side can be suppressed. The offset property on the side can be improved. Therefore, it is also preferable to contain a trivalent or higher carboxylic acid.

  Examples of the trivalent or higher carboxylic acid include trimellitic acid such as 1,2,4-benzenetricarboxylic acid and 1,2,5-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, and hemimerlic acid. , Trimesic acid, merophanic acid, planitic acid, pyromellitic acid, meritic acid, 1,2,3,4-butanetetracarboxylic acid, and acid anhydrides, acid chlorides and lower alkyl esters having 1 to 3 carbon atoms Among them, trimellitic acid (anhydride) is particularly preferable.

  These may be used individually by 1 type and may use 2 or more types together.

  The amorphous resin can be produced by the same method as that for the crystalline polyester resin.

  Here, the content of the amorphous resin with respect to the whole white toner is preferably 30 to 80% by mass, more preferably 34 to 75% by mass, and still more preferably 36 to 70% by mass. By setting this range, it is possible to obtain a sufficient fixed image strength and chargeability.

  The content of the amorphous resin with respect to the other toners is preferably 60 to 95% by mass, more preferably 76 to 90% by mass, and still more preferably 76 to 85% by mass. By setting this range, it is possible to obtain a sufficient fixed image strength and chargeability.

  As described above, the linear aliphatic dicarboxylic acid and the linear aliphatic diol contained in the toner of the present invention (particularly, the white toner) can be derived from a crystalline polyester resin or an amorphous polyester resin. From the viewpoint of heat resistance and heat-resistant storage property of the toner, it is preferably derived from a crystalline polyester resin. The crystalline polyester resin may be a modified polyester resin as long as the modifying component is 50% by mass or less.

<Total amount of linear aliphatic dicarboxylic acid and linear aliphatic diol (Tw and Tc)>
In this specification, the “total amount of linear aliphatic dicarboxylic acid and linear aliphatic diol” refers to the amount of “linear aliphatic dicarboxylic acid” and “linear aliphatic diol” with respect to “whole toner”. is there.

  The total amount of the linear aliphatic dicarboxylic acid and the linear aliphatic diol can be determined by the amount of raw materials charged.

  Further, even after the toner is produced, the total amount can be quantified. Specifically, there are the following methods.

  For example, the amount of the linear aliphatic dicarboxylic acid and the amount of the linear aliphatic diol in the toner are determined by a methylation reaction pyrolysis gas chromatograph mass spectrometry (GC / MS) method. Hydrolysis and methylation of the ester skeleton in the toner binder is performed using tetramethylammonium hydroxide as an organic alkali reagent for reaction pyrolysis, and the toner is removed from the peak obtained from the gas chromatograph mass spectrometer of the reaction product. Qualitative and quantitative analysis of the constituent monomers can be performed. As another method, the constituent monomer species and their ratios are calculated by performing alkaline hydrolysis with sodium hydroxide or the like, and qualitative and quantitative analysis of the decomposition products by high performance liquid chromatography (HPLC) or the like. .

<Contents of crystalline polyester (T′w and T′c)>
In this specification, “content of crystalline polyester” means the amount of “crystalline polyester” with respect to “whole toner”.

  The content of the crystalline polyester can also be determined by the amount of raw material charged.

  Note that the content of the crystalline polyester after being produced as a toner is combined with analysis of constituent monomer composition and constituent ratio, and various analysis methods (TEM observation of dyed toner sections, endothermic peaks by DSC measurement, Solid state NMR etc.) can be combined and estimated.

  Moreover, as mentioned above, it can carry out by adjusting the preparation amount of a raw material as a method of satisfy | filling said Formula (1)-(4).

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

  Specific examples of the white colorant include inorganic pigments (for example, heavy calcium carbonate, light calcium carbonate, titanium oxide, aluminum hydroxide, titanium white, talc, calcium sulfate, barium sulfate, zinc oxide, and oxidation). Magnesium, magnesium carbonate, amorphous silica, colloidal silica, white carbon, kaolin, calcined kaolin, delaminated kaolin, aluminosilicate, sericite, bentonite, smectite, etc.), organic pigments (eg, polystyrene resin particles, urea polymarin resin) Particles). Moreover, the pigment which has a hollow structure, for example, a hollow resin particle, a hollow silica, etc. are mentioned. From the viewpoint of chargeability and concealability, the white colorant is preferably titanium oxide. Titanium oxide can use any crystal structure such as anatase type, rutile type and brookite type.

  Examples of the black colorant include carbon black such as furnace black, channel black, acetylene black, thermal black, and lamp black, and magnetic powder such as magnetite and ferrite.

  Examples of the colorant for magenta or red include C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48; 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 150, C.I. I. Pigment red 166, C.I. I. Pigment red 177, C.I. I. Pigment red 178, pigment red 184, C.I. I. And CI Pigment Red 222.

  Examples of the colorant for orange or yellow include C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 155, C.I. I. Pigment yellow 180, C.I. I. And CI Pigment Yellow 185.

  Further, as a colorant for green or cyan, C.I. I. Pigment blue 15, C.I. I. Pigment blue 15; 2, C.I. I. Pigment blue 15; 3, C.I. I. Pigment blue 15; 4, C.I. I. Pigment blue 16, C.I. I. Pigment blue 60, C.I. I. Pigment blue 62, C.I. I. Pigment blue 66, C.I. I. And CI Pigment Green 7.

  These colorants can be used alone or in combination of two or more as required.

  The addition amount of the colorant is in the range of 1 to 60% by mass, preferably 2 to 35% by mass with respect to the “total toner”, and a mixture thereof can also be used. Within such a range, the color reproducibility of the image can be ensured.

  Moreover, as a magnitude | size of a coloring agent, 10-1000 nm and 50-500 nm are preferable at a volume average particle diameter, Furthermore, 80-300 nm is especially preferable.

  Since the other toner is a toner constituting the image forming layer (B) adjacent to the image forming layer (A), for example, an image forming method (apparatus) using yellow, magenta, cyan, and black in addition to white. ), Any toner can be used as the toner constituting the image forming layer (B).

  The white toner and other toners may contain an internal additive such as a release agent and a charge control agent; and an external additive such as inorganic fine particles, organic fine particles, and a lubricant, as necessary.

(Release agent (wax))
The release agent is not particularly limited, and known ones can be used. Specifically, for example, low molecular weight polyolefins such as polyethylene, polypropylene and polybutene; plant waxes such as synthetic ester wax, carnauba wax, rice wax, candelilla wax, wood wax, jojoba oil; montan wax, paraffin wax , Minerals such as microcrystalline wax and Fischer-Tropsch wax, petroleum-based wax; and modified products thereof. These release agents may be used alone or in combination of two or more.

  The addition amount of the release agent is usually 0.5 to 25% by mass, preferably 3 to 20% by mass with respect to “the whole toner”. Within such a range, there are effects of preventing hot offset and ensuring separability.

  The size of the release agent (volume-based median diameter) in the case of obtaining a toner by the emulsion aggregation method is preferably 10 to 1000 nm, 50 to 500 nm, and more preferably 80 to 300 nm.

(Charge control agent)
Various known compounds can be used as the charge control agent. Examples of the charge control agent include a nigrosine-based electron-donating dye, a metal salt of naphthenic acid or higher fatty acid, an alkoxylated amine, a quaternary ammonium salt, an alkylamide, a metal complex, a pigment, and a fluorine treatment activity. Examples of agents for negative charging include electron-accepting organic complexes, chlorinated paraffins, chlorinated polyesters, and sulfonylamines of copper phthalocyanine.

  The addition amount of the charge control agent is usually 0.1 to 10 parts by mass, preferably 0.5 to 5 parts by mass with respect to 100 parts by mass of the binder resin in the finally obtained toner.

(External additive)
From the viewpoint of improving the charging performance, fluidity, and cleaning properties of the toner, particles such as known inorganic fine particles and organic fine particles and a lubricant can be added to the toner surface as external additives.

  Preferred inorganic fine particles include inorganic fine particles made of silica, titania (titanium oxide), alumina, strontium titanate, or the like. Two or more of these may be combined.

  If necessary, these inorganic fine particles may be hydrophobized. The degree of hydrophobicity is preferably about 60 to 70.

  The number average primary particle diameter of the inorganic fine particles is about 10 to 2000 nm.

  As the organic fine particles, spherical organic fine particles having a number average primary particle diameter of about 10 to 2000 nm can be used. Specifically, homopolymers such as styrene and methyl methacrylate and organic fine particles made of these copolymers can be used.

  The lubricant is used for the purpose of further improving the cleaning property and transferability. Examples of the lubricant include zinc stearate, salts of aluminum, copper, magnesium, calcium, and zinc oleate. Of higher fatty acids, such as salts of manganese, iron, copper, magnesium, zinc of palmitic acid, salts of copper, magnesium, calcium, zinc of linoleic acid, salts of calcium, zinc of ricinoleic acid, salts of calcium, etc. Metal salts are mentioned. A variety of these external additives may be used in combination.

  The addition amount of the external additive is preferably 0.1 to 10.0% by mass with respect to the whole toner.

  Examples of the method of adding the external additive include a method of adding using various known mixing apparatuses such as a Turbuler mixer, a Henschel mixer, a Nauter mixer, and a V-type mixer.

(Toner production method)
The method for producing the toner is not particularly limited, and examples thereof include known methods such as a kneading and pulverizing method, a suspension polymerization method, an emulsion aggregation method, a dissolution suspension method, a polyester elongation method, and a dispersion polymerization method. Among these, it is preferable to employ the emulsion aggregation method from the viewpoint of the uniformity of the particle size, the controllability of the shape, and the ease of forming the core-shell structure. Therefore, in the following, the emulsion aggregation method will be described in detail.

<Emulsion aggregation method>
In the emulsion aggregation method, a dispersion of resin fine particles (hereinafter also referred to as “resin fine particles”) dispersed with a surfactant or a dispersion stabilizer is mixed with a dispersion of toner components such as fine particles of a colorant. In this method, the toner particles are aggregated by adding an aggregating agent to a desired toner particle diameter, and thereafter or simultaneously with the aggregation, the resin fine particles are fused together to form the toner.

  Here, the resin fine particles may be composite particles formed of a plurality of layers having two or more layers made of resins having different compositions.

  When an internal additive is contained in the toner, the resin fine particles may contain an internal additive. Alternatively, a dispersion of internal additive fine particles consisting of only the internal additive is separately prepared, and the internal additive is added. The fine particles may be aggregated together when the resin fine particles are aggregated.

  Also, a toner having a core-shell structure can be obtained by an emulsion aggregation method. Specifically, a toner having a core-shell structure first aggregates binder resin fine particles and colorant fine particles for core particles. , (Fused) to produce core particles, and then the binder resin fine particles for the shell layer are added to the dispersion of the core particles, and the binder resin fine particles for the shell layer are aggregated on the surface of the core particles. It can be obtained by forming a shell layer that covers the surface of the core particles by fusing.

  When the toner is produced by the emulsion aggregation method, the toner production method according to a preferred embodiment is based on the premise that the relationship of the above formula (1) is satisfied, and at least one of the crystalline resin fine particle dispersion and the amorphous resin fine particle dispersion, And a step of preparing a colorant dispersion (hereinafter also referred to as a preparation step) (1), at least one of a crystalline resin fine particle dispersion and an amorphous resin fine particle dispersion, and a colorant dispersion are mixed to form an aggregate And a step of fusing (hereinafter also referred to as aggregating / fusing step) (2).

  Hereinafter, each process is explained in full detail.

(1) Preparation Step More specifically, the step (1) includes a step of preparing at least one of a crystalline resin fine particle dispersion and an amorphous resin fine particle dispersion, and a colorant dispersion, and Accordingly, a release agent dispersion preparation step and the like are included.

(1-1) Crystalline resin fine particle dispersion preparation step / Amorphous resin fine particle dispersion preparation step In the crystalline resin fine particle dispersion preparation step, a crystalline resin is synthesized and the crystalline resin is finely divided in an aqueous medium. In this process, a dispersion of crystalline resin fine particles is prepared. The amorphous resin fine particle dispersion preparing step is a step of synthesizing an amorphous resin and dispersing the amorphous resin in the form of fine particles in an aqueous medium to prepare a dispersion of amorphous resin fine particles. is there.

  As a method of dispersing a crystalline resin / amorphous resin in an aqueous medium, an oil phase liquid is prepared by dissolving or dispersing the crystalline resin in an organic solvent (solvent), and the oil phase liquid is phase-inverted. A method of removing the organic solvent after dispersing in an aqueous medium by emulsification or the like to form oil droplets in a state of being controlled to a desired particle size is mentioned.

  The organic solvent (solvent) used for the preparation of the oil phase liquid is preferably one having a low boiling point and low solubility in water from the viewpoint of easy removal after the formation of oil droplets. Specific examples include methyl acetate, ethyl acetate, methyl ethyl ketone, isopropyl alcohol, methyl isobutyl ketone, toluene, xylene and the like. These can be used alone or in combination of two or more.

  The amount of the organic solvent (solvent) used (when two or more types are used, the total amount used) is usually 1 to 300 parts by weight, preferably 10 to 200 parts by weight, more preferably 25 to 100 parts by weight of the resin. -150 parts by mass.

  Furthermore, ammonia, sodium hydroxide, or the like may be added to the oil phase liquid in order to dissociate the carboxyl group ions and stably emulsify the aqueous phase to facilitate the emulsification.

  The amount of the aqueous medium used is preferably 50 to 2,000 parts by mass and more preferably 100 to 1,000 parts by mass with respect to 100 parts by mass of the oil phase liquid. By making the usage-amount of an aqueous medium into said range, an oil phase liquid can be emulsified and dispersed to a desired particle size in an aqueous medium.

  A dispersion stabilizer may be dissolved in the aqueous medium, and a surfactant or resin fine particles may be added for the purpose of improving the dispersion stability of the oil droplets.

  Examples of the dispersion stabilizer include inorganic compounds such as tricalcium phosphate, calcium carbonate, titanium oxide, colloidal silica, and hydroxyapatite, but it is necessary to remove the dispersion stabilizer from the obtained toner base particles. Therefore, it is preferable to use an acid or alkali-soluble material such as tricalcium phosphate, or from the environmental viewpoint, it is preferable to use a material that can be decomposed by an enzyme.

  As surfactants, surfactants include polyoxyethylene lauryl ether sodium sulfate, alkylbenzene sulfonates, α-olefin sulfonates, phosphate esters and other anionic surfactants, alkylamine salts, amino alcohol fatty acids Derivatives, polyamine fatty acid derivatives, amine salt types such as imidazoline, quaternary ammonium salt types such as alkyltrimethylammonium salt, dialkyldimethylammonium salt, alkyldimethylbenzylammonium salt, pyridinium salt, alkylisoquinolinium salt, benzethonium chloride Cationic surfactants, fatty acid amide derivatives, non-ionic surfactants such as polyhydric alcohol derivatives, alanine, dodecyl di (aminoethyl) glycine, di (octylaminoethyl) glycine and N-a Kill -N, N-amphoteric surfactants such as dimethyl ammonium betaine, and the like, also, the anionic surfactants and cationic surfactants having a fluoroalkyl group can be used.

  Such emulsification and dispersion of the oil phase liquid can be performed using mechanical energy, and the disperser for performing the emulsification and dispersion is not particularly limited. Examples thereof include an ultrasonic disperser, a friction disperser, a high-pressure jet disperser, an ultrasonic disperser such as an ultrasonic homogenizer, and a high-pressure impact disperser optimizer.

  The removal of the organic solvent after the formation of the oil droplets is performed by gradually heating the whole dispersion liquid in which the crystalline resin fine particles / amorphous resin fine particles are dispersed in the aqueous medium in a constant temperature range. In step 1, after strong stirring, the solvent may be removed. Alternatively, it can be removed while reducing the pressure using an apparatus such as an evaporator.

  The particle diameter of the crystalline resin fine particles (oil droplets) or amorphous resin fine particles (oil droplets) in the prepared crystalline resin fine particle dispersion or amorphous resin fine particle dispersion is a volume average particle size, The thickness is preferably 60 to 1000 nm, and more preferably 80 to 500 nm. In addition, a volume average particle diameter is measured by the method as described in an Example. The volume average particle diameter of the oil droplets can be controlled by the magnitude of mechanical energy during emulsification dispersion.

  In addition, the content of the crystalline resin fine particles or the amorphous resin fine particles in the crystalline resin fine particle dispersion or the amorphous resin fine particle dispersion is in the range of 10 to 50% by mass with respect to 100% by mass of the dispersion. More desirably, it is in the range of 15 to 40% by mass. Within such a range, the spread of the particle size distribution can be suppressed and the toner characteristics can be improved.

(1-2) Colorant Fine Particle Dispersion Preparation Step This colorant fine particle dispersion preparation step is an essential step in the case of white toner, and is also a step performed when a colored toner is desired as the toner. In this step, the colorant is dispersed in the form of fine particles in an aqueous medium to prepare a dispersion of colorant fine particles.

  The aqueous medium is as described above, and a surfactant or resin fine particles may be added to the aqueous medium for the purpose of improving dispersion stability.

  Dispersion of the colorant can be performed using mechanical energy, and such a disperser is not particularly limited, and as mentioned above, a low-speed shear disperser, a high-speed shear disperser Examples thereof include an ultrasonic disperser such as a disperser, a friction disperser, a high-pressure jet disperser, and an ultrasonic homogenizer, or a high-pressure impact disperser optimizer.

  The volume average particle size of the colorant fine particles is preferably 10 to 300 nm, and more preferably 100 to 200 nm.

  In addition, the content of the colorant fine particles in the colorant fine particle dispersion is preferably in the range of 10 to 50% by mass, and more preferably in the range of 15 to 40% by mass. Within such a range, there is an effect of ensuring color reproducibility.

(1-3) Release Agent Fine Particle Dispersion Preparation Step This release agent fine particle dispersion preparation step is a step that is performed as necessary when a toner containing a release agent is desired. In this step, the agent is dispersed in the form of fine particles in an aqueous medium to prepare a release agent fine particle dispersion.

  The aqueous medium is as described above, and a surfactant or resin fine particles may be added to the aqueous medium for the purpose of improving dispersion stability.

  The release agent can be dispersed using mechanical energy. Such a disperser is not particularly limited, and as mentioned above, a low-speed shear disperser, a high-speed shear Examples thereof include ultrasonic dispersers, friction dispersers, high pressure jet dispersers, ultrasonic dispersers such as ultrasonic homogenizers, high pressure impact dispersers, optimizers, and high pressure homogenizers.

  In dispersing the release agent, heating may be performed as necessary.

  The volume average particle size of the release agent fine particles is preferably 10 to 300 nm.

  Further, the content of the release agent fine particles in the release agent fine particle dispersion is preferably in the range of 10 to 50% by mass, and more preferably in the range of 15 to 40% by mass. Within such a range, there are effects of preventing hot offset and ensuring separability.

(2) Aggregation / fusion process This aggregation / fusion process is carried out by at least one of a crystalline resin fine particle dispersion and an amorphous resin fine particle dispersion, a colorant fine particle dispersion, and, if necessary, a release agent. Add and mix other components such as fine particle dispersion, slowly agglomerate while balancing the repulsive force of the fine particle surface by pH adjustment and the agglomeration force by the addition of an aggregating agent consisting of an electrolyte, the average particle size and This is a step of forming toner by performing association while controlling the particle size distribution, and simultaneously performing shape control by fusing fine particles by heating and stirring. This agglomeration / fusion process can also be performed using mechanical energy or heating means as required.

  In the aggregating step, first, the obtained dispersions are mixed to form a mixed solution, which is heated and aggregated at a temperature not higher than the glass transition temperature of the amorphous resin to form aggregated particles. Aggregated particles are formed by acidifying the pH of the mixed solution with stirring. As pH, the range of 2-7 is desirable, The range of 2.2-6 is more desirable, The range of 2.4-5 is still more desirable. At this time, it is also effective to use a flocculant.

  As the flocculant to be used, a surfactant having a reverse polarity to the surfactant used for the dispersant, an inorganic metal salt, and a metal complex having a valence of 2 or more can be preferably used.

  Examples of inorganic metal salts include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate, and inorganic substances such as polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. Examples thereof include metal salt polymers. Of these, aluminum salts and polymers thereof are particularly preferred. In order to obtain a sharper particle size distribution, it is more suitable that the valence of the inorganic metal salt is bivalent than monovalent, trivalent than bivalent, and tetravalent than trivalent.

  When the agglomerated particles have reached a desired particle size, the toner (core-shell particles) having a structure in which the surface of the core agglomerated particles is coated with the amorphous resin is added by adding amorphous fine particles. Can do. In the case of additional addition, a flocculant may be added or pH adjustment may be performed before additional addition.

  During the aggregation, it is preferable to heat and raise the temperature. At this time, if the temperature becomes higher than the fusing temperature due to heating and temperature rise, the fusing process also proceeds at the same time. The heating rate is preferably 0.1 to 5 ° C./min.

  When the aggregated particles have a desired particle size, aggregation of various fine particles in the reaction system is stopped (hereinafter also referred to as an aggregation stop step). In order to suppress the aggregating action of the fine particles in the reaction system, the agglomeration is stopped by adjusting the pH in a direction away from the pH environment in which the aggregating action of the fine particles in the aggregating process is promoted. This is done by adding an agent. The desired particle size of the aggregated particles is not particularly limited, but the volume median diameter (volume-based median diameter) is preferably about 4.5 to 7.0 μm.

  In this aggregation stopping step, it is preferable to adjust the pH of the reaction system to 5.0 to 9.0.

  As the aggregation terminator (base compound), alkali metal salts such as ethylenediaminetetraacetic acid (EDTA) and its sodium salt, gluconal, sodium gluconate, potassium citrate and sodium citrate, nitrotriacetate (NTA) salt, GLDA (commercially available) L-glutamic acid N, Ndiacetic acid), humic acid and fulvic acid, maltol and ethyl maltol, pentaacetic acid and tetraacetic acid, known water-soluble polymers having both carboxyl group and hydroxyl group (polymer electrolyte) , Sodium hydroxide, potassium hydroxide and the like. In the aggregation stopping step, stirring may be performed according to the aggregation step.

  In the fusing step, after passing through the agglomeration stopping step or simultaneously with the agglomeration step, the reaction system is heated to a desired fusing temperature, thereby fusing the fine particles constituting the agglomerated particles to form the agglomerated particles. It is a process of fusing to form fused particles.

  The fusing temperature in this fusing step is preferably equal to or higher than the melting point of the crystalline polyester resin, and the fusing temperature is preferably 0 to 20 ° C. higher than the melting point of the crystalline polyester resin. The heating time may be as long as fusion is performed, and may be performed for about 0.5 to 10 hours.

  In this aggregation / fusion process, a surfactant may be added to the aqueous medium in order to stably disperse each fine particle in the aggregation system.

  The addition ratio (mass ratio) of amorphous resin fine particles / crystalline polyester resin fine particles in the aggregation / fusion process is not limited in each binder resin as long as the relationship of the above formula (1) is satisfied.

  Cool after fusion to obtain fused particles. The cooling rate is preferably 0.4 to 20 ° C./min. When a toner is obtained by the emulsion aggregation method, the volume median diameter of the toner can be controlled by the timing of the aggregation stop step.

  In the fusion process, it is preferable to control the degree of circularity, and specifically, heat treatment for heating the particles obtained in the aggregation / fusion process can be given. Circularity can be controlled by heating temperature and holding time. The circularity can be made close to 1 by increasing the heating temperature or increasing the holding time.

  The heating temperature in the circularity control process may be adjusted as appropriate, but is preferably 70 to 95 ° C.

  Further, the toner production method in the emulsion aggregation method may include (4) a filtration / washing step, (5) a drying step, and (6) an external additive adding step.

(4) Filtration / Washing Step In this filtration / washing step, the obtained toner dispersion is cooled to form a cooled slurry, and a toner such as water is used from the cooled toner dispersion. A solidification process is performed to separate the toner and the toner is filtered, and a cleaning process is performed to remove deposits such as surfactants from the filtered toner (cake-like aggregate). Specific examples of the solid-liquid separation and washing method include a centrifugal separation method, a vacuum filtration method using an aspirator, Nutsche and the like, a filtration method using a filter press, etc., and these are not particularly limited. . In this filtration / washing step, pH adjustment or pulverization may be performed as appropriate. Such an operation may be repeated.

(5) Drying step In this drying step, the toner that has been subjected to the washing treatment is dried. Dryers used in this drying process include ovens, spray dryers, vacuum freeze dryers, vacuum dryers, stationary shelf dryers, mobile shelf dryers, fluidized bed dryers, rotary dryers, and stirrers A dryer etc. are mentioned, These are not specifically limited. The water content measured by Karl Fischer coulometric titration in the dried toner is preferably 5% by mass or less, and more preferably 2% by mass or less.

  In addition, when the dried toner aggregates with a weak interparticle attractive force to form an aggregate, the aggregate may be crushed. Here, as the crushing treatment apparatus, a mechanical crushing apparatus such as a jet mill, a comb mill, a Henschel mixer, a coffee mill, or a food processor can be used.

(6) External additive addition step This external additive addition step is a step of adding a charge control agent, various inorganic fine particles, organic matter to the dried toner for the purpose of improving fluidity, chargeability and cleaning properties. A step of adding an external additive such as fine particles or a lubricant, which is performed as necessary. Examples of the apparatus used for adding the external additive include various known mixing apparatuses such as a Turbuler mixer, a Henschel mixer, a Nauter mixer, a V-type mixer, and a sample mill. Further, sieving classification may be performed as necessary in order to make the particle size distribution of the toner within an appropriate range.
Good.

(Developer)
For example, the above toner may be used as a one-component magnetic toner containing a magnetic material, mixed with a so-called carrier to be used as a two-component developer, or a non-magnetic toner may be used alone. Any of these can be suitably used.

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

  The carrier preferably has a volume average particle diameter of 15 to 100 μm, more preferably 25 to 60 μm.

  As the carrier, it is preferable to use a carrier coated with a resin, or a so-called resin dispersion type carrier in which magnetic particles are dispersed in a resin. The resin composition for coating is not particularly limited. For example, olefin resin, cyclohexyl methacrylate / methyl methacrylate copolymer, styrene resin, styrene-acrylic resin, silicone resin, ester resin, or fluorine-containing resin. Polymer based resins and the like are used. In addition, the resin for constituting the resin-dispersed carrier is not particularly limited, and known resins can be used. For example, acrylic resins, styrene-acrylic resins, polyester resins, fluorine resins, phenolic resins Resin etc. can be used.

(Image forming method)
The image forming method of the present invention comprises a step of forming an image forming layer (A) on a recording medium using a white toner; and an adjacent to the image forming layer (A) using a toner different from the white toner. As described above, the image forming layer (B) is formed; and the image forming layer (A) and the image forming layer (B) are fixed.

  In this case, after fixing the image forming layer (A) obtained by transferring the white toner onto the recording medium, a method for fixing the image forming layer (B) obtained by transferring other toner onto the recording medium, Examples of the method include fixing the image forming layer (A) obtained by transferring the white toner onto the recording medium and the image forming layer (B) obtained by transferring other toner onto the recording medium. Since the effects of the present invention can be further obtained and image formation is fast, it is preferable to form an image by fixing the image forming layer (A) and the image forming layer (B) together.

  Preferably, the electrostatic latent image electrostatically formed on the image bearing member is made visible by charging the developer with a friction charging member in a developing device to obtain a toner image (image forming layer). The toner image is transferred onto a recording medium, and then the toner image transferred onto the recording medium is fixed on a recording material by a contact heating type fixing process, whereby a visible image is obtained.

  A suitable fixing method includes a so-called contact heating method. Examples of the contact heating method include a heat pressure fixing method, a heat roll fixing method, and a pressure contact heat fixing method in which fixing is performed by a rotating pressure member including a fixedly arranged heating body.

  In the fixing method of the hot roll fixing method, usually, an upper roller provided with a heat source inside a metal cylinder made of iron or aluminum whose surface is coated with fluororesin, etc., and a lower roller formed of silicone rubber or the like Is used.

  As the heat source, a linear heater is used, and the surface temperature of the upper roller is heated to about 120 to 200 ° C. by this heater. A pressure is applied between the upper roller and the lower roller, and the lower roller is deformed by this pressure, so that a so-called nip is formed in the deformed portion. The width of the nip is 1 to 10 mm, preferably 1.5 to 7 mm. The fixing linear velocity is preferably 40 to 600 mm / sec.

(recoding media)
The recording medium (also referred to as recording material, recording paper, recording paper, etc.) may be a commonly used one, for example, as long as it holds a toner image formed by a known image forming method using an image forming apparatus or the like. It is not particularly limited. Examples of usable image supports include plain paper from thin paper to thick paper, high-quality paper, art paper, coated printing paper such as coated paper, commercially available Japanese paper and postcard paper, OHP Plastic film, cloth and the like.

(Image forming device)
The present invention further includes an image forming layer (A) obtained by using a white toner, an image forming layer (B) obtained by using a toner adjacent to the image forming layer (A) and different from the white toner, Is formed on the recording medium, and the total amount of linear aliphatic dicarboxylic acid and linear aliphatic diol constituting the binder resin contained in the white toner is Tw, which is different from the white toner When the total amount of linear aliphatic dicarboxylic acid and linear aliphatic diol constituting the binder resin contained in the toner is Tc,
Following formula (1):

An image forming apparatus that satisfies the above is also provided.

  As for the configuration of the image forming apparatus, the toner may be installed in a known image forming apparatus. As an image forming apparatus equipped with white toner and other toners, for example, JP-A-2002-236396 can be cited.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to said aspect, A various change can be added.

  The effects of the present invention will be described using the following examples and comparative examples. Of course, the present invention is not limited to these embodiments. In the examples, “parts” or “%” may be used, but “parts by mass” or “% by mass” is indicated unless otherwise specified. Unless otherwise specified, each operation is performed at room temperature (25 ° C.).

[Preparation Example of Amorphous Resin]
(1) Synthesis of amorphous resin [1] 85 parts by mass of terephthalic acid (TPA), 6 parts by mass of trimellitic acid (TMA), 18 parts by mass of fumaric acid (FA), 80 parts by mass of dodecenyl succinic anhydride (DDSA) , 335 parts by mass of bisphenol A propylene oxide adduct (BPA · PO) and 55 parts by mass of bisphenol A ethylene oxide adduct (BPA · EO) are placed in a reaction vessel equipped with a stirrer, thermometer, cooling pipe, and nitrogen gas introduction pipe. Then, after the inside of the reaction vessel was replaced with dry nitrogen gas, 0.1 part by mass of titanium tetrabutoxide was added, and a polymerization reaction was performed for 8 hours while stirring at 180 ° C. under a nitrogen gas stream. Further, 0.2 parts by mass of titanium tetrabutoxide is added, the temperature is raised to 220 ° C., and the polymerization reaction is performed for 6 hours while stirring. Then, the reaction container is depressurized to 10 mmHg, and the reaction is performed for 2 hours under reduced pressure. As a result, a pale yellow transparent amorphous resin [1] was obtained.

  The amorphous resin [1] had a weight average molecular weight (Mw) of 32,000.

  The glass transition point (Tg) of the amorphous resin was obtained by differential scanning calorimetry (DSC). Using a differential scanning calorimeter (manufactured by PerkinElmer; diamond DSC), 3.0 mg of amorphous resin is sealed in an aluminum pan, set in a sample holder of “Diamond DSC”, and heated at a rate of 10 ° C./min. The first temperature rising process in which the temperature is raised from room temperature to 150 ° C. and then held at 150 ° C. for 5 minutes, the cooling process in which the temperature is cooled from 150 ° C. to 0 ° C. at a cooling rate of 10 ° C./min and then held at 0 ° C. for 5 minutes. In addition, in the measurement conditions through the second temperature raising process in which the temperature is raised from room temperature to 150 ° C. at a temperature raising rate of 10 ° C./min, the onset temperature in the DSC curve during the second temperature raising process is defined as the glass transition temperature. . The reference used an empty aluminum pan. The glass transition point (Tg) of this amorphous resin [1] was 59 ° C.

(2) Synthesis of amorphous resin [2] 85 parts by mass of terephthalic acid (TPA), 6 parts by mass of trimellitic acid (TMA), 18 parts by mass of fumaric acid (FA), 80 parts by mass of dodecenyl succinic anhydride (DDSA) 1,10-decanedicarboxylic acid (dodecanedioic acid) 73.3 parts by mass, bisphenol A propylene oxide adduct (BPA · PO) 335 parts by mass, bisphenol A ethylene oxide adduct (BPA · EO) 55 parts by mass, 1, 58.6 parts by mass of 9-nonanediol was put into a reaction vessel equipped with a stirrer, a thermometer, a cooling tube, and a nitrogen gas introduction tube, and in the same manner as the amorphous resin [1], the amorphous resin [2] ] Was obtained.

  This amorphous resin [2] had a glass transition point (Tg) of 42 ° C. and a weight average molecular weight (Mw) of 33,000.

[Example of preparation of amorphous resin fine particle dispersion]
(1) Preparation of Amorphous Resin [1] Fine Particle Dispersion After dissolving 200 parts by mass of amorphous resin [1] in 200 parts by mass of ethyl acetate, polyoxyethylene lauryl ether sodium sulfate was added to 800 parts by mass of ion-exchanged water. Was mixed with an aqueous solution in which the concentration was 1% by mass and dispersed using an ultrasonic homogenizer.

  1200 parts by mass of the obtained emulsified liquid was put into a 2 liter eggplant flask and set in an evaporator (Tokyo Rika Kikai Co., Ltd.) equipped with a vacuum control unit via a trap ball. While rotating the eggplant flask, the mixture was heated in a hot water bath at 60 ° C., and the solvent was removed by reducing the pressure to 7 kPa while paying attention to bumping. When the solvent recovery amount reached 400 parts by mass, the pressure was returned to normal pressure, and the eggplant flask was cooled with water to obtain a dispersion. Ion exchange water was added to the obtained dispersion to adjust the solid content concentration to 20% by mass. Thus, an amorphous resin [1] fine particle dispersion in which fine particles of the amorphous resin [1] were dispersed in an aqueous medium was prepared.

  The volume-based median diameter of the fine particles of the amorphous resin [1] was 230 nm. The median diameter was measured using a particle size distribution measuring apparatus “UPA-150” (manufactured by Nikkiso Co., Ltd.).

(2) Preparation of Amorphous Resin [2] Fine Particle Dispersion Amorphous Resin [2] Fine Particle Dispersion, except that Amorphous Resin [2] was used instead of Amorphous Resin [1] A liquid was prepared.

  The volume-based median diameter of the fine particles of the amorphous resin [2] was 230 nm. The median diameter was measured using a particle size distribution measuring apparatus “UPA-150” (manufactured by Nikkiso Co., Ltd.).

[Preparation example of crystalline resin fine particle dispersion]
(1) Synthesis of crystalline resin 315 parts by mass of 1,10-decanedicarboxylic acid (dodecanedioic acid) and 252 parts by mass of 1,9-nonanediol are equipped with a stirrer, thermometer, cooling pipe, and nitrogen gas introduction pipe. The reactor was replaced with dry nitrogen gas, 0.1 parts by mass of titanium tetrabutoxide was added, and a polymerization reaction was carried out for 8 hours with stirring at 180 ° C. in a nitrogen gas stream. Furthermore, after adding 0.2 parts by mass of titanium tetrabutoxide, raising the temperature to 220 ° C. and carrying out the polymerization reaction for 6 hours while stirring, the inside of the reaction vessel was reduced to 10 mmHg and the reaction was carried out under reduced pressure. Crystalline resin [1] was obtained.

  The crystalline resin [1] had a weight average molecular weight (Mw) of 14,000.

  The melting point (Tm) of the crystalline resin was obtained by differential scanning calorimetry (DSC). Crystalline polyester (1.5 mg) is sealed in an aluminum pan, and the endothermic peak temperature in the DSC curve during the second temperature rise process is measured as crystalline under the same measurement conditions as the glass transition point (Tg) measurement of an amorphous resin. The melting point of the resin. The melting point (Tm) of the crystalline resin [1] was 72 ° C. Moreover, the half width of crystalline polyester was 2.3 degreeC.

(2) Preparation of crystalline resin fine particle dispersion After dissolving 200 parts by mass of crystalline resin in 200 parts by mass of ethyl acetate heated to 70 ° C., polyoxyethylene lauryl ether sodium sulfate is added to 800 parts by mass of ion-exchanged water. Was mixed with an aqueous solution dissolved so as to be 1% by mass, and dispersed using an ultrasonic homogenizer. 1200 parts by mass of the obtained emulsified liquid was put into a 2 liter eggplant flask and set in an evaporator (Tokyo Rika Kikai Co., Ltd.) equipped with a vacuum control unit via a trap ball. While rotating the eggplant flask, it was heated in a hot water bath at 60 ° C., and the pressure was reduced to 7 kPa while paying attention to bumping to remove the solvent. When the solvent recovery amount reached 400 parts by mass, the pressure was returned to normal pressure, and the eggplant flask was cooled with water to obtain a dispersion. Ion exchange water was added to the obtained dispersion to adjust the solid content concentration to 20% by mass. Thereby, a crystalline resin fine particle dispersion in which fine particles of the crystalline resin were dispersed in an aqueous medium was prepared.

  The volume-based median diameter of the fine particles of the crystalline resin was 210 nm. The median diameter was measured using a particle size distribution measuring apparatus “UPA-150” (manufactured by Nikkiso Co., Ltd.).

[Preparation Example of Colorant Fine Particle Dispersion (White)]
Rutile type titanium oxide (manufactured by Ishihara Sangyo Co., Ltd.) 210 parts by mass is added to a surfactant aqueous solution in which 1% by weight of sodium alkyldiphenyl ether disulfonate is dissolved in 480 parts by weight of ion-exchanged water, and then dispersed using an ultrasonic homogenizer. went. The solid content concentration was adjusted to 30%. The average particle size was 200 nm.

[Preparation Example of Colorant Fine Particle Dispersion (Cyan)]
After adding 50 parts by mass of copper phthalocyanine (CI Pigment Blue 15: 3) to a surfactant aqueous solution dissolved in 200 parts by mass of ion-exchanged water so as to have a concentration of 1% by mass of sodium alkyldiphenyl ether disulfonate, Dispersion treatment was performed using a sonic homogenizer. The solid content concentration was adjusted to 20% by mass. Thus, a colorant fine particle dispersion in which colorant fine particles are dispersed in an aqueous medium was prepared. The average particle size was 150 nm.

  The average particle diameter of the colorant fine particles in the colorant fine particle dispersion was a volume-based median diameter, and was measured using a Microtrac particle size distribution measuring device “UPA-150” (manufactured by Nikkiso Co., Ltd.).

[Preparation Example 1 of Release Agent Fine Particle Dispersion]
Mold release agent: Fischer-Tropsch wax “FNP-0090” (melting point 89 ° C., manufactured by Nippon Seiwa Co., Ltd.) 200 parts by mass was heated to 95 ° C. and dissolved. This was further added to a surfactant aqueous solution dissolved in 800 parts by mass of ion-exchanged water so that the sodium alkyldiphenyl ether disulfonate had a concentration of 3% by mass, and then subjected to a dispersion treatment using an ultrasonic homogenizer. The solid content concentration was adjusted to 20% by mass. As a result, a release agent fine particle dispersion in which the release agent fine particles are dispersed in an aqueous medium was prepared.

  The volume-based median diameter of the release agent fine particles in the release agent fine particle dispersion was measured using a Microtrac particle size distribution analyzer “UPA-150” (manufactured by Nikkiso Co., Ltd.) and found to be 190 nm.

[Production example of white toner]
(1) Production Example of White Toner 1 Amorphous resin [1] 376.1 parts by mass of fine particle dispersion, 85.6 parts by mass of crystalline resin fine particle dispersion, 94.4 parts by mass of release agent fine particle dispersion, coloring The agent fine particle dispersion 222.2 parts by mass and the polyoxyethylene lauryl ether sodium sulfate aqueous solution 0.5 parts by mass were put into a reaction vessel equipped with a stirrer, a condenser tube, and a thermometer, Hydrochloric acid was added to adjust the pH to 2.5. Next, after 0.4 parts by mass of an aqueous polyaluminum chloride solution (10% aqueous solution in terms of AlCl ₃ ) was added dropwise over 10 minutes, the temperature was raised at a rate of 0.05 ° C./min while stirring, “Multisizer 3” ( The particle size of the agglomerated particles was appropriately measured by Beckman Coulter Co.). When the volume-based median diameter of the aggregated particles reached 5.0 μm, the temperature increase was stopped, and 222.2 parts by mass of the amorphous resin [1] fine particle dispersion was dropped over 1 hour for shell formation. . Thereafter, the pH in the system was set to 8.5 with a 0.5N sodium hydroxide aqueous solution, and the particle size growth was stopped. Further, the internal temperature was raised to 85 ° C., and when “FPIA-2000” (manufactured by Sysmex) was used, the average circularity reached 0.960, and the reaction was cooled to room temperature at a rate of 10 ° C./min. The liquid was repeatedly filtered and washed, and then dried to obtain a white toner [1].

  To the obtained white toner [1], 1% by mass of hydrophobic silica (number average primary particle size = 12 nm, hydrophobicity = 68) and hydrophobic titanium oxide (number average primary particle size = 20 nm, hydrophobicity = 63). ) 1% by mass was added, mixed by “Henschel mixer” (manufactured by Mitsui Miike Chemical Co., Ltd.), and then coarse particles were removed using a 45 μm mesh sieve to obtain white toner 1. The volume-based median diameter of the white toner 1 was 5.6 μm, and the average circularity was 0.965.

(2) Production Example of White Toner 2 White toner 1 except for changing to 344.9 parts by mass of amorphous resin [1] fine particle dispersion and 116.7 parts by mass of crystalline resin fine particle dispersion for core formation. A white toner 2 was obtained in the same manner. The volume-based median diameter of the white toner 2 was 5.6 μm, and the average circularity was 0.963.

(3) Production Example of White Toner 3 Same as white toner 1 except for changing to 306 parts by mass of amorphous resin [1] fine particle dispersion and 155.6 parts by mass of crystalline resin fine particle dispersion for core formation. Thus, white toner 3 was obtained. The volume-based median diameter of the white toner 3 was 5.6 μm, and the average circularity was 0.965.

(4) Production Example of White Toner 4 White toner 1 except for changing to 267.1 parts by weight of the amorphous resin [1] fine particle dispersion and 194.5 parts by weight of the crystalline resin fine particle dispersion for core formation. A white toner 4 was obtained in the same manner as described above. The volume-based median diameter of the white toner 4 was 5.6 μm, and the average circularity was 0.964.

(5) Production Example of White Toner 5 White toner 1 was used except for changing to 228.2 parts by mass of the amorphous resin [1] fine particle dispersion and 233.4 parts by mass of the crystalline resin fine particle dispersion for core formation. A white toner 5 was obtained in the same manner. The volume-based median diameter of the white toner 5 was 5.6 μm, and the average circularity was 0.962.

(6) Production Example of White Toner 6 Same as white toner 1 except for changing to 461.6 parts by weight of amorphous resin [2] fine particle dispersion and 0 parts by weight of crystalline resin fine particle dispersion for core formation. As a result, white toner 6 was obtained. The volume-based median diameter of the white toner 6 was 5.6 μm, and the average circularity was 0.965.

(7) Production Example of White Toner 7 White toner 1 except for changing to 383.8 parts by mass of the amorphous resin [1] fine particle dispersion and 77.8 parts by mass of the crystalline resin fine particle dispersion for core formation. A white toner 7 was obtained in the same manner as described above. The volume-based median diameter of the white toner 7 was 5.6 μm, and the average circularity was 0.964.

(8) Production Example of White Toner 8 White toner 1 except for changing to 422.7 parts by mass of amorphous resin [1] fine particle dispersion and 38.9 parts by mass of crystalline resin fine particle dispersion for core formation. In the same manner, white toner 8 was obtained. The volume-based median diameter of the white toner 8 was 5.6 μm, and the average circularity was 0.963.

(9) Production Example of White Toner 9 Same as white toner 1 except for changing to 461.6 parts by weight of amorphous resin [1] fine particle dispersion and 0 parts by weight of crystalline resin fine particle dispersion for core formation. As a result, white toner 9 was obtained. The volume-based median diameter of the white toner 9 was 5.6 μm, and the average circularity was 0.965.

[Production example of colored toner]
(1) Production Example of Colored Toner 1 For core formation, amorphous resin [1] 583 parts by weight of fine particle dispersion, 70 parts by weight of crystalline resin fine particle dispersion, 85 parts by weight of release agent fine particle dispersion, colorant A colored toner 1 was obtained in the same manner as the white toner 1 except that 62 parts by mass of the fine particle dispersion and 200 parts by mass of the amorphous resin for forming a shell [1] particle dispersion. The volume-based median diameter of the colored toner 1 was 5.6 μm, and the average circularity was 0.965.

(2) Production Example of Colored Toner 2 The same procedure as in Colored Toner 1 except for changing to 603 parts by mass of the amorphous resin [1] fine particle dispersion and 50 parts by mass of the crystalline resin fine particle dispersion for core formation. Colored toner 2 was obtained. The volume-based median diameter of the colored toner 2 was 5.6 μm, and the average circularity was 0.964.

(3) Production Example of Colored Toner 3 In the same manner as Colored Toner 1 except for changing to 653 parts by mass of the amorphous resin [1] fine particle dispersion and 0 part by mass of the crystalline resin fine particle dispersion for core formation. Colored toner 3 was obtained. The volume-based median diameter of the colored toner 3 was 5.6 μm, and the average circularity was 0.965.

<Developer>
(Preparation of resin-coated carrier)
100 parts by mass of Mn—Mg ferrite particles and 2.0 parts by mass of copolymer resin fine particles of cyclohexyl methacrylate / methyl methacrylate (copolymerization ratio 5/5) were put into a high-speed mixer equipped with stirring blades, and 120 ° C. for 30 minutes. Then, after stirring and mixing at a wind speed of 10 M / S and forming a resin coating layer on the surface of the core particles by the action of mechanical impact force, cooling was performed by lowering the wind speed to 2 M / S to prepare a resin-coated carrier.

(Preparation of toner developer)
40 parts by weight of the white toner 1 is added to 500 parts by weight of the resin-coated carrier, blended for 20 minutes with a V-type blender, and then aggregates are removed by a vibrating screen having an aperture of 212 μm. Was prepared. Similarly, developers for white toners 2 to 9 were prepared. Also, developers of colored toners 1 to 3 were prepared.

<Total amount of linear aliphatic dicarboxylic acid and linear aliphatic diol>
“Total amount of linear aliphatic dicarboxylic acid and linear aliphatic diol” of each toner is shown in Table 1.

  The “total amount of linear aliphatic dicarboxylic acid and linear aliphatic diol” of each toner can be calculated from the amount of raw materials charged.

  More specifically, in the white toners 1 to 5, “linear aliphatic dicarboxylic acid” and “linear aliphatic diol” are contained only in the raw material of “crystalline resin (crystalline polyester)”. Therefore, the amount (% by weight) of the “crystalline resin (crystalline polyester)” in the amount of the whole white toner (binder resin, release agent, colorant, external additive), that is, “linear aliphatic dicarboxylic acid” The total amount of acid and linear aliphatic diol ".

For example, taking white toner 1 as an example;
Core [amorphous resin (376.1 × 0.2) + crystalline resin (crystalline polyester) (85.6 × 0.2) + release agent (94.4 × 0.2) + colorant ( 222.2 × 0.3)] + shell [amorphous resin (222.2 × 0.2)] + external additive (1 mass% (2.22) +1 mass% (2.22)) = 226 .76
“Total amount of linear aliphatic dicarboxylic acid and linear aliphatic diol” in white toner 1 = amount of crystalline resin (crystalline polyester) = (85.6 × 0.2) /226.76) × 100 = 7 .5.

  On the other hand, the white toner 6 does not contain a crystalline resin (crystalline polyester), but the raw material of the “amorphous resin” includes “linear aliphatic dicarboxylic acid” and “linear aliphatic diol”. Therefore, by calculating the weight percentage of the entire white toner (binder resin, mold release agent, colorant, external additive), “linear aliphatic dicarboxylic acid and linear aliphatic diol” The total amount can be calculated.

Specifically, in the white toner 6,
Core [amorphous resin (461.6 × 0.2) + crystalline resin (crystalline polyester) (0) + release agent (94.4 × 0.2) + colorant (222.2 × 0. 3)] + shell [amorphous resin (222.2 × 0.2)] + external additive (1 mass% (2.22) +1 mass% (2.22)) = 226.7
[Dodecanedioic acid (73.3) + 1,9-nonanediol (58.6)] / [terephthalic acid (85) + trimellitic acid (6) + fumaric acid (18) + dodecenyl succinic anhydride (80) + Dodecanedioic acid (73.3) + BPA · PO (335) + BPA · EO (55) + 1,9-nonanediol (58.6)] × amorphous resin (461.6 × 0.2) = 17.1
Calculate “total amount of linear aliphatic dicarboxylic acid and linear aliphatic diol” = (17.1 / 226.7) × 100 = 7.5.

<Content of crystalline polyester>
“Content of crystalline polyester” of each toner is shown in Tables 1 and 2.

  The “content of crystalline polyester” of each toner can be calculated from the charged amount of raw material.

  More specifically, the white toners 1 to 5 and the colored toners 1 to 2 can be calculated in the same manner as described above, and the white toner 6 and the colored toner 3 include a crystalline resin (crystalline polyester). Because it is not, it is “0”. For reference, Table 2 also shows the contents (% by weight) of the amorphous resin, the release agent, and the colorant in each toner.

<Color development>
A commercially available composite printer “bizhub Pro C500” (manufactured by Konica Minolta Business Technologies Co., Ltd.) was modified to install a white toner image forming unit at the black position and a colored toner image forming unit at the cyan position. According to the combinations of developers shown in Examples 1 to 8 and Comparative Examples 1 to 3, each developer was put into a developing machine in the developing means, and the following evaluation was performed.

  Under an environment of a temperature of 20 ° C. and a humidity of 50% RH, a solid image (2 cm × 2 cm) was formed by superimposing a cyan image on a white toner image, and the image saturation was measured.

  When the saturation in the case of using the developer combination shown in Comparative Example 1 is set to 100, “x” means that the saturation improvement is less than 3%, and the saturation improvement is 3% or more but less than 5%. Evaluation was made with “Δ”, an improvement of 5% or more but less than 10% as “◯”, and an improvement of 10% or more as “◎”.

  As for the saturation of the image, a spectrophotometer “Gretag Macbeth Spectrolino” (manufactured by Gretag Macbeth) is used, a D65 light source as a light source, a φ4 mm reflection measurement aperture, a measurement wavelength region of 380 to 730 nm at 10 nm intervals, The angle is set to 2 °, and the measurement is performed under the condition using a dedicated white tile for reference alignment.

<(Low temperature) fixability>
As for the developer, in the full-color copier “bizhub PRO C6500” (manufactured by Konica Minolta Business Technologies) of a commercially available composite printer, the surface temperature of the fixing heat roller can be changed within the range of 100 to 210 ° C. Using this modified version, fixing an image with a color toner (on a white paper) and a white toner (on a black paper) of 5 mg / 10 cm ² on A4 (basis weight 80 g / m ² ) plain paper. The fixing experiment was repeatedly performed while changing the set fixing temperature to 100 ° C., 105 ° C., and so on in increments of 5 ° C.

  The printed matter obtained in the fixing experiment relating to each fixing temperature is folded by a folding machine so as to apply a load to the solid image, compressed air of 0.35 MPa is blown thereto, and the fold is shown in the following five evaluation criteria. The fixing temperature in the fixing experiment of rank 3 was defined as the lower limit fixing temperature.

The lower limit fixing temperature is;
165 ° C. or lower: ◎,
More than 165 ° C and 170 ° C or less: ○,
Over 170 ° C and below 175 ° C: Δ,
Over 175 ° C: x.

-Evaluation criteria-
Rank 5: No crease Rank 4: Partial peeling according to the fold Rank 3: Fine linear peeling according to the fold Rank 2: Thick linear peeling according to the fold Rank 1: There is a big peeling.

<Discussion>
When the toners of Examples 1 to 8 were used, neither “fixing property” nor “coloring property” was “x”, indicating that the results were satisfactory. On the other hand, in the comparative example, the result of “color development” is “x”, and it can be said that the problem of the present invention cannot be solved.

  When Examples 1 to 3 and Example 6 are compared with Examples 4 to 5, the former is superior in terms of “color development”. This is the following formula (2):

This is considered to be because

In addition, Examples 1 to 6 have better “color development” than Example 7,
Following formula (3):

It is thought that it is because it satisfies. That is, in Examples 1 to 6, since there is an appropriate relationship between Tw and Tc, it is suggested that the difference in melting rate can be adjusted, color mixing can be prevented, and color development can be improved.

  In addition, Examples 1 to 6 have better “color development” than Example 8 because the binder resin constituting the white toner of Examples 1 to 6 contains crystalline polyester. Thus, it is suggested that the linear aliphatic dicarboxylic acid and the linear aliphatic diol contained in the toner (particularly white toner) of the present invention are preferably derived from a crystalline polyester resin. .

  In addition, since “fixability” of Examples 1 to 5 and Example 8 is excellent, it is suggested that “the crystalline polyester has improved low-temperature fixability”.

Claims (5)

Forming an image forming layer (A) on a recording medium using white toner;
Forming the image forming layer (B) so as to be adjacent to the image forming layer (A) using a toner different from the white toner;
Fixing the image forming layer (A) and the image forming layer (B);
An image forming method comprising:
The total amount of linear aliphatic dicarboxylic acid and linear aliphatic diol constituting the binder resin contained in the white toner is Tw, and the linear fat constituting the binder resin contained in a toner different from the white toner When the total amount of the aliphatic dicarboxylic acid and the linear aliphatic diol is Tc,
Following formula (1):
To satisfy
The binder resin constituting the white toner includes an amorphous resin and a crystalline polyester, and the content of the amorphous resin with respect to the toner different from the white toner is 76 to 95% by mass, and the white toner The binder resin constituting the toner different from that contains crystalline polyester,
The content of the crystalline polyester contained in the binder resin constituting the white toner is Tw ′, and the content of the crystalline polyester contained in the binder resin constituting the toner different from the white toner is Tc ′. When
Following formula (4):
An image forming method that satisfies the above.   The image forming method according to claim 1, wherein the toner different from the white toner is a colored toner. Following formula (2):
The image forming method according to claim 1, wherein the image forming method satisfies the following conditions. Following formula (3):
The image forming method according to any one of claims 1 to 3, wherein: A toner set comprising: a white toner; and a toner different from the white toner used in the image forming layer (B) adjacent to the image forming layer (A) obtained by using the white toner,
The total amount of the linear aliphatic dicarboxylic acid and the linear aliphatic diol constituting the binder resin contained in the white toner is Tw,
When the total amount of the linear aliphatic dicarboxylic acid and the linear aliphatic diol constituting the binder resin contained in the toner different from the white toner is Tc,
Following formula (1):
The filling,
The binder resin constituting the white toner includes an amorphous resin and a crystalline polyester, and the content of the amorphous resin with respect to the toner different from the white toner is 76 to 95% by mass, and the white toner The binder resin constituting the toner different from that contains crystalline polyester,
The content of the crystalline polyester contained in the binder resin constituting the white toner is Tw ′, and the content of the crystalline polyester contained in the binder resin constituting the toner different from the white toner is Tc ′. When
Following formula (4):
Meet the toner set.