JP4466404B2 - Toner for developing electrostatic image and method for producing the same - Google Patents

Description

  The present invention relates to a toner for developing an electrostatic image and a method for producing the toner.

  The field of image forming technology based on electrophotography such as copying machines and printers is rapidly spreading with the progress of digitization technology, and the number of used devices has been greatly increased.

  In general, recent developments in electrophotographic technology are concentrated in the following four points, and energetic research and development is underway.

(1) Making the image forming apparatus compact (2) Speeding up the image forming apparatus (3) Realizing high-quality color image formation (4) Reducing power consumption during operation (saving) Electricity)
Here, in order to solve the above problems (1) to (3), even if image formation is performed by rotating a small-diameter roller at a high speed, image contamination due to toner scattering, deterioration of the developing roller due to toner fusion, etc. There is a difficulty that it must not cause problems. In response to these problems, a technique has been disclosed in which a toner with uniform chargeability is designed to increase the charging speed of the toner and increase the charge retention ability (see, for example, Patent Document 1).
In (4) power saving, the use of printers in offices due to the progress of the network environment and the use of digital devices such as printers and facsimiles in homes are becoming popular in offices and homes. As power usage increases, reducing rated power and power costs is an inevitable issue.

  In addition, the expansion of electrophotographic image forming technology to new fields means that there is no need to create a plate like in printing in the electrophotographic method, and as many documents as necessary can be created at high speed when necessary. Expansion to the print on demand (POD) area is expected.

  However, although the current image forming technology is excellent in speed, the usable paper types are limited, and image formation cannot be performed on all types of paper. For example, in the case of thin paper, wrinkles are likely to occur, and in general coated glossy paper, there has been a problem of occurrence of image defects (blisters) due to water vapor ejection. In addition, it has been difficult to develop color reproducibility that can form a beautiful color image without being affected by collation accuracy at the time of bookbinding or paper type.

  In order to achieve these problems, chemical toners typified by polymerized toner as in the above-mentioned Patent Document 1 have attracted attention, and it is possible to design a toner that dynamically controls the structure of the toner to solve these problems. Has been tried. For example, another resin particle is fused to the surface of a resin particle containing a resin and a colorant to form a resin layer to modify the toner surface, thereby suppressing the exposure of the colorant to the toner surface and increasing the humidity. Toner technology that enables stable image formation in the environment and the dispersion and occupancy of toner-containing components are controlled by the manufacturing process to form particles, making them less susceptible to environmental factors such as temperature and humidity. Although toner technology is mentioned, it has not been sufficient yet (see, for example, Patent Documents 2, 3, and 4).

In particular, a technique for improving the toner performance by coating the toner surface with a resin has been proposed, but the heat-resistant storage stability during storage and transportation has not been sufficiently improved. Further, it has been insufficient to maintain a stable charging speed and charge retention over a long period of time.
JP 2004-54240 A JP 2002-116574 A JP 2002-351142 A JP-A-10-26842

  The present invention has been made in view of the above problems, and is a toner for developing an electrostatic charge image (hereinafter also simply referred to as toner) used in an electrophotographic image forming apparatus such as a small-sized, high-speed output copying machine, printer, or facsimile. ) Is intended to solve the following problems.

  That is, according to the present invention, the charging speed and the charge holding ability are remarkably improved, a good and stable toner image can be output even if the developing device is downsized, and the toner image can be fixed on the transfer material at a low temperature. In addition, an object of the present invention is to provide a toner having excellent heat-resistant storage property in which toner particles do not aggregate even if the toner is stored or transported without being cooled or insulated.

  The present invention also provides a toner capable of forming a beautifully finished image having sufficient fixing strength and uniform glossiness even when the toner image is fixed at a low fixing temperature. The purpose is to do.

  It is another object of the present invention to provide a toner capable of forming a stable image on a paper type, such as glossy coated paper, thick paper, or thin paper, which has been very difficult to form with a conventional technique. Is. In other words, by expanding the selection range of paper types that can form toner images, we are developing print-on-demand image forming technology that can print only the required number of copies without having to bother to create a plate. An object of the present invention is to provide a toner that can be applied.

  The object of the present invention is achieved by taking the following configurations.

1. In the electrostatic charge image developing toner having a core-shell structure in which a shell layer containing resin B is coated on the surface of the core part containing resin A and a colorant,
When the glass transition temperature of the resin A is Tg1 and the glass transition temperature of the resin B is Tg2, Tg2-Tg1 ≧ 25 ° C., 10 ° C. ≦ Tg1 ≦ 30 ° C. , 50 ° C. ≦ Tg2 ≦ 65 ° C.
When the solubility parameter value of the resin A is SP1 and the solubility parameter value of the resin B is SP2, the difference (ΔSP) between SP1 and SP2 is 0.2 to 1.0,
The toner for developing an electrostatic charge image is obtained by salting out / fusing resin particles containing resin B on the surface of a core part containing resin A and a colorant to form a shell layer. An electrostatic charge image developing toner.

2. 2. The electrostatic image developing toner according to 1 above, wherein the resin A and the resin B are styrene-acrylic copolymer resins .

3. 3. The toner for developing an electrostatic charge image according to 1 or 2, wherein the toner contains 1 to 20 parts of a colorant with respect to 100 parts of the resin .

4). 4. The toner for developing an electrostatic charge image according to any one of 1 to 3 above, wherein the toner has a circularity of 0.94 to 0.99 .

5. 5. The toner for developing an electrostatic charge image according to any one of 1 to 4 above, wherein the thickness of the shell layer of the toner is 10 to 500 nm .

6). The weight average molecular weight of the resin A is the 1 electrostatic image developing toner according to any one of 4, which is a 5,000 to 30,000.

7). The weight average molecular weight of the resin B is, the 1 electrostatic image developing toner according to any one of 4, which is a 10,000 to 80,000.

8). In the method for producing a toner for developing an electrostatic charge image having a core-shell structure in which a shell layer containing resin B is coated on the surface of a core part containing resin A and a colorant,
When the glass transition temperature of the resin A is Tg1 and the glass transition temperature of the resin B is Tg2, Tg2-Tg1 ≧ 25 ° C., 10 ° C. ≦ Tg1 ≦ 30 ° C., 50 ° C. ≦ Tg2 ≦ 65 ° C.
When the solubility parameter value of the resin A is SP1 and the solubility parameter value of the resin B is SP2, the difference (ΔSP) between SP1 and SP2 is 0.2 to 1.0,
Production of an electrostatic charge image developing toner comprising a step of salting out / fusing resin particles containing resin B on the surface of a core containing resin A and a colorant to form a shell layer Way .

9. Step of forming a shell layer by salting out / fusion of resin particles containing resin B on the surface of the core obtained by salting out / fusion of resin particles containing resin A and colorant particles 9. The method for producing a toner for developing an electrostatic charge image according to 8 above, comprising :

10. 10. The method for producing a toner for developing an electrostatic charge image according to 8 or 9, wherein the resin particles containing the resin A are composite resin particles obtained by a multistage polymerization method.

  According to the present invention, the charging speed and the charge retention ability are remarkably improved, a good and stable toner image is output even if the developing device is downsized, and the toner image can be fixed to the transfer material at a low temperature. The present invention makes it possible to provide a toner having excellent heat-resistant storage properties in which toner particles do not aggregate even if the toner is stored or transported without being kept cold or insulated.

  That is, the toner obtained according to the present invention has a charging speed that can be used for high-speed development processing, and at the same time, can achieve both low-temperature fixability during fixing and heat-resistant storage during storage.

  Further, the melting at the time of thermal fixing progresses, the color reproduction region is expanded, and the occurrence of filming (fusion) on the surface of the photoreceptor, the surface of the developing roller, and the surface of the member in contact with the melted toner is suppressed.

  Furthermore, even when image formation is performed on thin paper, fixing wrinkles do not occur, and when image formation is performed on coated paper or thick paper, a uniform finish with uniform gloss and a beautiful finish can be obtained. The width of usable paper types can be expanded.

  The toner of the present invention has a structure in which a core layer containing a resin and a colorant is coated with a shell layer containing a resin.

  Further, the toner of the present invention is produced by forming a shell layer on the surface of the core portion containing the resin A and the colorant by salting out / sealing resin particles having the resin B by a salting out / fusion method. It has been done. The core part can be produced by salting out / fusion of resin particles having resin A and colorant particles.

  In the present invention, “salting out / fusing” means that salting out (aggregation of resin particles) and fusing (disappearance at the interface between resin particles) occur simultaneously, or salting out and fusing occur simultaneously. The act of letting go. In order to perform salting out and fusion at the same time, it is necessary to agglomerate the particles under a temperature condition equal to or higher than the glass transition temperature (Tg) of the resin constituting the resin particles.

<Setting of glass transition temperature Tg of resin>
Between resin particles formed using resin A (hereinafter also referred to as resin particles for core portion) and resin particles formed using resin B (hereinafter also referred to as resin particles for shell layer), resin When the glass transition temperature of A is Tg1 and the glass transition temperature of resin B is Tg2, Tg2−Tg1 ≧ 25 ° C., 10 ° C. ≦ Tg1 ≦ 30 ° C. , 50 ° C. ≦ Tg2 ≦ 65 ° C.

  Hereinafter, the toner of the present invention will be described in detail.

[Structure of toner of the present invention]
FIG. 1 is a schematic view showing the structure of the toner of the present invention.

  In FIG. 1, T is a toner, A is a core portion, B is a shell layer, 1 is a colorant particle, 2 is a resin A, and 3 is a resin B.

  The toner of the present invention is a resin particle formed by using a resin B having a glass transition temperature (Tg) different from that of the core part on the surface of the core part A containing the resin A and the colorant in the manufacturing process of the toner T. Is obtained by salting out / aggregating the shell layer B.

  In the toner of the present invention, the thickness of the shell layer is preferably 10 to 500 nm, and more preferably 100 to 300 nm.

  It has been confirmed that even if the shell layer does not necessarily completely cover the toner surface, the problem of the present invention can be solved if the shell layer exists in an area within 1 μm from the toner surface. As shown in the figure, by covering 40 to 100%, preferably 50 to 95%, of the toner surface, both low temperature fixability and heat resistant storage stability during storage can be achieved. Moreover, even if a part of the shell layer enters the inside of the core part as shown in FIG. 1- (b), even if the whole surface of the core part is covered with the shell layer as shown in FIG. The effect of.

  Here, the shell layer is formed when a layer covering the outer surface of the core part (also referred to as a coating) has a surface coverage of 30% or more by surface area on the outer surface of the core part. Is defined as formed.

  In the present invention, the surface coverage and film thickness of the shell layer are determined from the presence of a colorant (carbon black, yellow pigment, magenta pigment, cyan pigment, etc.) or a release agent from a TEM (transmission electron microscope) photograph of the toner. The region (core portion) is confirmed by visual observation, the distance from the outermost surface of the toner to the core portion is randomly measured at 10 points, and the film thickness of the shell layer is calculated from the average value. Note that the number of toners for TEM photography is at least 50.

  As a photographing method using a transmission electron microscope, a generally known method for measuring toner is used. That is, as a specific method for measuring the tomographic surface of the toner, the toner is placed in a room temperature curable epoxy resin. May be embedded and cured, after being dispersed in a styrene fine powder having a particle size of about 100 nm and after being pressure-molded, the block obtained may be converted to ruthenium tetroxide or tetra After dyeing together with osmium trioxide, a flaky sample is cut out using a microtome with diamond teeth, and the tomographic form of the toner is photographed using a transmission electron microscope (TEM).

  Here, examples of the transmission electron microscope include LEM-2000 type (manufactured by Topcon Corporation), JEM-2000FX (manufactured by JEOL Ltd.), and the like.

  The toner of the present invention has been confirmed to have stable charge retention performance. As described above, it is not clear why the stable charge retention performance is manifested, but the toner of the present invention probably has a charge between the core portion and the shell layer after the charge density on the toner surface reaches a certain level. This is presumed to be that a certain level of charge can be held on the toner surface at all times by being movable. That is, in the toner of the present invention, when charge is generated and the charge density on the toner surface reaches a certain level, it is presumed that the charge moves to the core portion and the charge is held in the whole toner. Since the charges transferred to the core can move to the shell layer, it is presumed that even if the charge density on the toner surface decreases, the charge immediately moves to the shell layer and maintains the charge density on the toner surface.

  On the other hand, in the conventional toner, the charge is accumulated only on the outermost surface of the toner, and the charge does not move into the particles. Even if the charge density on the toner surface is lowered, it is presumed that the charge retention performance is reduced because it does not have enough charge to compensate for it.

  It is not clear why the toner of the present invention can achieve both the low temperature fixability and the heat resistant storage stability during storage, but the core and shell layers are probably incompatible at the molecular level. Therefore, even if the core part inside the toner is made of a resin having a low softening temperature and a low glass transition temperature, the resin constituting the shell layer is affected by the resin constituting the core part, and the glass transition temperature is lowered or plasticized. It is presumed that a phenomenon such as crystallization will not occur. As a result, the toner of the present invention is presumed to be able to achieve both the low temperature fixability and the heat resistant storage stability.

[Detection of toner structure]
The structure of the toner of the present invention can be sufficiently observed with a transmission electron microscope (TEM) by cutting the toner into 80 to 200 nm sections. Examples of the transmission electron microscope (TEM) include “H-9000NAR” (manufactured by Hitachi, Ltd.), “JEM-200FX” (manufactured by JEOL Ltd.), and the like. In the present invention, the size of the core portion and the thickness of the shell layer in the toner can be calculated from the projection surface of ten or more toners at a magnification of 10,000 based on the result of the transmission electron micrograph. Note that the magnification of observation can be adjusted within a range in which the sectional structure of one toner can be understood.

  The observation method using a transmission electron microscope is performed by a normal method used when measuring toner. For example, the procedure is as follows. First, materials for observation are prepared. After the toner is sufficiently dispersed in the room temperature curable epoxy resin, it is embedded and cured to produce a block. The prepared block is cut into a thin piece having a thickness of 80 to 200 nm using a microtome equipped with diamond teeth to prepare a measurement sample. Next, a photograph of the cross-sectional shape of the toner is taken using a transmission electron microscope (TEM). The resin composition in the toner is visually confirmed from the photograph. If necessary, it is also possible to measure the particle size of the core portion and the thickness of the shell layer in the toner by performing arithmetic processing on image information captured by an image processing apparatus “Luzex F” (manufactured by Nicolet). is there.

  In some cases, the measurement sample may be dyed with ruthenium tetroxide, osmium tetroxide, or the like.

[Realization of Toner of the Present Invention]
Next, means for realizing the toner of the present invention will be described.

The toner of the present invention has a core-shell structure in which a core layer containing resin A and a colorant is coated with a shell layer containing resin B. The glass transition temperature of resin A is Tg1. When the glass transition temperature of the resin B is Tg2, Tg2−Tg1 ≧ 25 ° C., 10 ° C. ≦ Tg1 ≦ 30 ° C. , 50 ° C. ≦ Tg2 ≦ 65 ° C.

  The glass transition temperatures of the resin A forming the core part and the resin B forming the shell layer can be controlled by appropriately selecting the type, amount and molecular weight of the polymerizable monomer forming the copolymer. is there.

  In the toner of the present invention, the resin particles forming the shell layer and the core portion form a layer structure between the core portion and the shell portion by setting the difference between the glass transition temperatures of both to Tg2−Tg1 ≧ 20 ° C. The heat-resistant storage property of the toner is ensured.

  Further, in the toner of the present invention, it is preferable that the glass transition temperature of the core portion is 10 ° C. ≦ Tg 1 ≦ 30 ° C. so that good low-temperature fixability is expressed. Ensuring mechanical strength, heat-resistant storage stability and fixing property by the shell layer is well expressed by setting the glass transition temperature of the resin B forming the shell layer to 50 ° C. ≦ Tg 2 ≦ 65 ° C.

  The method for adjusting the glass transition temperature is, for example, selecting the type of polymer monomer of the resin B constituting the shell layer and the A resin constituting the core portion from the compounds described later, and setting the glass transition temperature of both to the above range. It becomes possible by adjusting the ratio and molecular weight so that However, the exemplary compounds are shown for clarifying the achievement means, and are not limited thereto.

[Setting of glass transition temperature]
As a method for calculating the glass transition temperature, the following theoretical glass transition temperature may be calculated in the present invention. Here, the theoretical glass transition temperature is calculated by multiplying the glass transition temperature when each component constituting the copolymer resin forms a homopolymer by the respective composition mass fraction, that is, by weighted averaging. It is.

  That is, the theoretical glass transition temperature Tg (referred to as absolute temperature Tg ′) is calculated from the following formula (1) using the glass transition temperature of the homopolymer of the component constituting the copolymer resin.

Formula (1)
1 / Tg '= W1 / T1 + W2 / T2 + ... + Wn / Tn
(Wherein W1, W2,... Wn are the mass fraction of each polymerizable monomer relative to the total polymerizable monomer constituting the copolymer resin, and T1, T2... Tn are each polymerizable monomer. (The glass transition temperature (absolute temperature) of the homopolymer formed using the monomer is shown.)
[Measurement of glass transition temperature]
The glass transition temperature can be measured by a differential calorimeter (DSC). An example of the measuring device is DSC-7 manufactured by PerkinElmer.

  A specific method for measuring the glass transition temperature is, for example, as a temperature raising / cooling condition, after standing at −30 ° C. for 1 minute, the temperature is raised to 100 ° C. under a condition of 10 ° C./min (first temperature raising process). Then, after standing at 100 ° C. for 1 minute, it is cooled to 0 ° C. under the condition of 10 ° C./min (first cooling process). This operation deletes the previous history. Next, after standing at 0 ° C. for 1 minute, the temperature is raised to 100 ° C. under a condition of 10 ° C./min (second temperature raising process). And the method of calculating | requiring the endothermic peak temperature of 2nd heat (2nd temperature rising) and making it Tg is mentioned.

  The glass transition temperature Tg is determined by measuring the baseline extension line below the glass transition point of the DSC thermogram in the glass transition region and the tangent line indicating the maximum slope from the peak rising portion to the peak apex. The temperature of the intersection point is defined as the glass transition temperature.

  The glass transition temperature can also be measured using an atomic force microscope. That is, the temperature of the atomic force microscope stage is heated to 0 to 60 ° C., and the temperature at which the hardness of the toner slice or block changes may be set as the glass transition temperature Tg.

  In the toner of the present invention, there may be some difference in the value of the theoretical glass transition temperature, the measurement result obtained with the differential calorimeter, or the result with the atomic force microscope. It does not deny the technical idea of or affect the results.

[Softening temperature]
The softening temperature (Tsp) of the toner of the present invention is preferably 70 to 98 ° C. When toner having this softening temperature is used, fixing is possible even when the temperature of the transfer material surface during fixing is 100 ° C. or lower. This is because in the toner of the present invention, the ratio of the shell layer is 2 to 30% on a mass basis with respect to the toner, so that the degree of influence on the softening temperature is small, and the heat storage stability of the toner is improved and the fixing property is improved. It is possible to make it better. Therefore, the toner of the present invention enables fixing at a temperature at which image defects due to the generation of water vapor and deformation (curl) of the transfer material do not occur.

  The toner softening temperature can be controlled, for example, by controlling the type of monomer constituting the resin used to form the resin particles and the monomer composition ratio of the copolymer, and the amount of chain transfer agent. Examples thereof include a method for controlling the degree of polymerization, a method for adjusting the type and amount of a fixing aid such as a release agent added to the toner, and the like, and by combining these, a toner having a desired softening temperature can be obtained. As an example, there is a method of controlling the softening temperature by plotting the relationship between the molecular weight and the softening temperature in a specific resin.

As a method for measuring the softening temperature of the toner, for example, “Flow Tester CFT-500” (manufactured by Shimadzu Corporation) is used, and the sample is preliminarily set to 9.2 mesh pass (aperture 2.0 mm), 32 mesh on (mesh After opening up to a particle size of 0.5 mm), it was formed into a 10 mm high cylindrical shape, and a 20 kg / cm ² load was applied from the plunger while heating at a heating rate of 6 ° C./min. A nozzle of 1 mm is pushed out, thereby drawing a curve (softening flow curve) between the plunger drop amount of the flow tester and the temperature (softening flow curve), and the temperature corresponding to the drop amount of 5 mm is used as the softening temperature.

[Solubility parameter value]
In the present invention, the resin forming the shell layer in the toner is not compatible with the resin in the core portion, and the resin forming the shell layer has sufficient adhesiveness with the core portion.

  In order for the resin forming the shell layer to exhibit incompatibility with the core part, the solubility parameter value of the resin forming the shell layer (hereinafter also referred to as SP value) and the solubility parameter of the resin forming the core part This is realized by setting the difference between values within an appropriate range.

  The solubility parameter value (SP value) is a numerical value representing the magnitude of the cohesive energy of a substance. According to the method “Polym. Eng. Sci., Vol 14, P 147 (1974)” proposed by Feors, When the evaporation energy and the molar volume are Δer and Δvi, respectively, the solubility parameter value σ of the binder resin is calculated by the following equation (2).

Formula (2)
σ = (ΣΔer / ΣΔvi) ^1/2
The solubility parameter value of each vinyl copolymer is calculated by the product of the solubility parameter value of each component and the molar ratio. For example, assuming that the copolymer resin is composed of two types of monomers, X and Y, the mass composition ratio of each monomer is x, y (mass%), the molecular weight is Mx, My, When the solubility parameter values are SPx and SPy, the monomer ratios are x / Mx (mol%) and y / My (mol%). Here, when the molar ratio of the copolymer resin is C, it is expressed as C = x / Mx + y / My, and the solubility parameter value SP of the copolymer resin is represented by the following formula (3).

Formula (3)
SP = [(x × SPx / Mx) + (y × SPy / My)] × 1 / C
The solubility parameter values SPx and SPy of each monomer are calculated by the above formula (2), and specific values are described in documents such as Polymer Handbook (published by Wiley) 4th edition. Use what you have.

  The solubility parameter value can be controlled by changing the composition ratio of the monomers constituting the vinyl copolymer. For example, a copolymer resin formed using styrene and methyl methacrylate is used. Thus, it has been confirmed that the solubility parameter value tends to decrease by decreasing the composition ratio of styrene and increasing the composition ratio of methyl methacrylate.

  In addition, for an overview of the solubility parameter of the polymer material, the solubility parameter item described in the database “PolyInfo (http://polymer.nims.go.jp)” provided by the National Institute for Materials Science (http://polymer.nims.go.jp) //Polymer.nims.go.jp/guide/guide/p5110.html).

  In the present invention, the solubility parameter value of the resin contained in the core part and the shell layer exhibits stable incompatibility when the difference between the shell layer and the core part is 0.1 or more, preferably 0. The range of 2 to 0.8 is more preferable.

[Toner circularity]
The toner of the present invention is preferably a toner having an average circularity of 0.94 to 0.99 and an average equivalent circle diameter of 2.6 to 7.4 μm. More preferably, the average value of the circularity of the toner is 0.95 to 0.98.

  When toner containing untransferred toner recovered by using such toner is passed through a toner intermediate chamber having a structure in which gas is introduced from the upper part and gas is discharged from the lower part, normal toner and toner are more efficiently contained. Can be separated from impurities such as paper dust, broken toner, agglomerated toner, and free external additives. As a result, impurities in the toner can be efficiently removed as compared with conventional toners, so that white spots and black spots do not occur even when a recording medium (transfer material) that generates much paper dust or the like is used. It is possible to form an image that is sufficiently satisfactory. Further, by reusing unfixed toner, resource saving and cost reduction are achieved.

  The average value of the circularity is a value obtained from the following formula (3) when 2000 or more toners having a particle diameter of 1 μm or more are measured.

Formula (3)
Circularity = (perimeter of equivalent circle) / (perimeter of toner projection image)
= 2π × (particle projected area / π) ^1/2 / (peripheral length of toner projected image)
Here, the equivalent circle is a circle having the same area as the toner projection image, and the equivalent circle diameter is the diameter of the equivalent circle.

  In addition, as a measuring method of the said circularity, it can measure with "FPIA-2000" (made by Sysmec). At this time, the equivalent circle diameter is defined by the following formula (4).

Formula (4)
Equivalent circle diameter = 2 × (projected area of particle / π) ^1/2
[Molecular weight]
In producing the toner of the present invention, it is preferable to set the molecular weight of the resin forming the core and shell layers in the toner within a specific range.

  Specifically, the resin constituting the core part has a weight average molecular weight of 5,000 to 30,000, the resin constituting the shell layer has a weight average molecular weight of 10,000 to 80,000, and the resin constituting the core part. It is preferable to set the peak molecular weight in the range of 15,000 to 28,000, and the weight average molecular weight of the resin constituting the shell layer in the range of 10,000 to 50,000.

  Next, materials used in the present invention will be described.

"resin"
The glass transition temperature of the resin used in the present invention can be controlled by changing the composition ratio of the monomers constituting the vinyl copolymer, and is formed using, for example, styrene and butyl methacrylate. In the case of the copolymer resin, it has been confirmed that the glass transition temperature increases by increasing the composition ratio of styrene and decreasing the composition ratio of butyl methacrylate.

  The resin A forming the core part and the resin B forming the shell layer are preferably styrene-acrylic copolymer resins.

  Examples of the monomer for forming the resin forming the core include propyl acrylate, propyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, and other glass transition temperatures ( It is preferable to copolymerize a polymerizable monomer that lowers Tg).

  The copolymer ratio of the polymerizable monomer in the copolymer resin forming the core part is 8 to 80% by mass, and preferably 9 to 70% by mass.

  In addition to the above, these polymerizable monomers may have an acid, acid anhydride, or vinyl carboxylic acid metal salt form.

  Moreover, in this invention, you may form copolymer resin which forms a core part together using a styrene-type monomer.

  It is preferable to copolymerize the monomer which produces resin which forms a shell layer with the polymerizable monomer which raises the glass transition temperature (Tg) of copolymers, such as styrene, methyl methacrylate, and methacrylic acid.

  The copolymer ratio of the polymerizable monomer in the copolymer resin forming the shell layer is 8 to 80% by mass, and preferably 9 to 20% by mass.

  In addition to the above, these polymerizable monomers may have a form of an acid anhydride or a vinyl carboxylic acid metal salt.

(Polymerizable monomer)
As the polymerizable monomer for obtaining the resin constituting the toner of the present invention, a radically polymerizable monomer is an essential component, and at least one selected from radically polymerizable monomers having an acidic group in particular. It is preferred to use different types of monomers. Moreover, a crosslinking agent can also be used as needed. Examples of such radical polymerizable monomers include aromatic vinyl monomers, (meth) acrylic acid ester monomers, vinyl ester monomers, vinyl ether monomers, monoolefin monomers, Examples include diolefin monomers and halogenated olefin monomers.

  Examples of the group vinyl monomer include styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, p-metharomatic styrene, p-phenyl styrene, p-chloro styrene, p-ethyl styrene, p- n-butyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, 2,4 -Styrene monomers such as dimethylstyrene and 3,4-dichlorostyrene and derivatives thereof.

  Examples of the aromatic vinyl monomer include styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, p-meth aromatic xy styrene, p-phenyl styrene, p-chloro styrene, p-ethyl styrene, p. -N-butyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, 2, Examples thereof include styrene monomers such as 4-dimethylstyrene and 3,4-dichlorostyrene and derivatives thereof.

  Examples of (meth) acrylate monomers include, for example, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, methacryl Examples include butyl acid, hexyl methacrylate, 2-ethylhexyl methacrylate, ethyl β-hydroxyacrylate, propyl γ-aminoacrylate, stearyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, and the like.

  Examples of vinyl ester monomers include vinyl acetate, vinyl propionate, and vinyl benzoate.

  Examples of vinyl ether monomers include vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, vinyl phenyl ether, and the like.

  Examples of the monoolefin monomer include ethylene, propylene, isobutylene, 1-butene, 1-pentene, 4-methyl-1-pentene and the like.

  Examples of the diolefin monomer include butadiene, isoprene, chloroprene and the like.

  Examples of the halogenated olefin monomer include vinyl chloride, vinylidene chloride, vinyl bromide and the like.

  Examples of the radical polymerizable monomer having an acidic group include carboxylic acid group-containing monomers such as acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, cinnamic acid, maleic acid monobutyl ester, and maleic acid monooctyl ester. Examples thereof include sulfonic acid group-containing monomers such as styrene sulfonic acid, allyl sulfosuccinic acid, and octyl allyl sulfosuccinate. All or part of the radical polymerizable monomer having an acidic group may have a structure of an alkali metal salt such as sodium or potassium or an alkaline earth metal salt such as calcium. The proportion of the radical polymerizable monomer having an acidic group in the monomer (monomer mixture) used is preferably 0.1 to 20% by mass, more preferably 0.1 to 15% by mass. It is.

  In order to improve the properties such as stress resistance of the toner, a radical polymerizable crosslinking agent may be added and copolymerized with the radical polymerizable monomer. Examples of such radically polymerizable crosslinking agents include compounds having two or more unsaturated bonds such as divinylbenzene, divinylnaphthalene, divinyl ether, diethylene glycol methacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, diallyl phthalate and the like. The proportion of the radical polymerizable crosslinking agent in the monomer (monomer mixture) used is preferably 0.1 to 10% by mass.

(Chain transfer agent)
In order to adjust the molecular weight of the resin, a commonly used chain transfer agent can be used. The chain transfer agent to be used is not particularly limited, for example, mercaptans such as octyl mercaptan, dodecyl mercaptan, tert-dodecyl mercaptan, mercaptopropionate such as n-octyl-3-mercaptopropionate, terpinolene, four Carbon bromide and α-methylstyrene dimer are used.

(Radical polymerization initiator)
The radical polymerization initiator used in the present invention can be appropriately used as long as it is water-soluble. For example, persulfates such as potassium persulfate and ammonium persulfate, azo compounds such as 4,4′-azobis-4-cyanovaleric acid and its salts, 2,2′-azobis (2-amidinopropane) salt, peroxide compounds, etc. Is mentioned.

  Furthermore, you may use the said radical polymerization initiator as a redox-type initiator combined with the reducing agent as needed. By using a redox initiator, the polymerization activity is increased, the polymerization temperature can be lowered, and the polymerization time can be further shortened.

(Surfactant)
The surfactant that can be used when emulsion polymerization is performed using the radical polymerizable monomer is not particularly limited, but the following ionic surfactants are preferably used.

  Examples of ionic surfactants include sulfonates (sodium dodecylbenzenesulfonate, sodium arylalkylpolyethersulfonate, 3,3-disulfonediphenylurea-4,4-diazo-bis-amino-8-naphthol-6 Sodium sulfonate, ortho-carboxybenzene-azo-dimethylaniline, 2,2,5,5-tetramethyl-triphenylmethane-4,4-diazo-bis-β-naphthol-6-sodium sulfonate, etc.), sulfuric acid Ester salts (sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, etc.), fatty acid salts (sodium oleate, sodium laurate, sodium caprate, sodium caprylate, sodium caproate, stearic acid) Potassium, calcium oleate), and the like.

  Nonionic surfactants can also be used. Specifically, polyethylene oxide, polypropylene oxide, combination of polypropylene oxide and polyethylene oxide, ester of polyethylene glycol and higher fatty acid, alkylphenol polyethylene oxide, ester of higher fatty acid and polyethylene glycol, ester of higher fatty acid and polypropylene oxide, sorbitan ester However, if necessary, the polymerization may be carried out in combination with the ionic surfactant described above.

  In the present invention, these are mainly used as an emulsifier at the time of emulsion polymerization, but may be used for other processes or purposes, for example, as a dispersing agent for associated particles.

《Colorant》
As the colorant used in the present invention, all known dyes and pigments can be used. Specifically, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium Yellow, yellow iron oxide, ocher, titanium yellow, polyazo yellow, oil yellow, Hansa yellow (GR, A, RN, R), pigment yellow L, permanent yellow (NCG), Vulcan fast yellow (5G, R), tart Rajn Lake, Quinoline Yellow Lake, Anthrazan Yellow BGL, Isoindolinone Yellow, Bengala, Permanent Red 4R, Para Red, Faise Red, Parachlor Ortho Nitroaniline Red, Resol Fast Scarlet G, Brilliant Fast Scarlet, Brillia Tokarmin BS, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Resol Rubin GX, Permanent Red F5R, Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Torujin 5B Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thioindigo Red B, Thioindigo Maroon, Oil Red, Quinacridone Red , Pyrazolone red, polyazo red, chrome vermilion, benzidine orange, perinone orange, oil orange, Baltic Blue, Cerulean Blue, Alkaline Blue Lake, Peacock Blue Lake, Victoria Blue Lake, Metal-free Phthalocyanine Blue, Phthalocyanine Blue, Fast Sky Blue, Indanthrene Blue (RS, BC), Indigo, Ultramarine Blue, Bituminous Blue, Anthraquinone Blue, Fast Violet B, Methyl Violet Lake, Cobalt Purple, Manganese Purple, Dioxane Violet, Anthraquinone Violet, Chrome Green, Zinc Green, Pyridian, Emerald Green, Pigment Green B, Naphthol Green B, Green Gold, Acid Green Lake, Malachite Green Lake, Phthalocyanine Green, anthraquinone green, titanium oxide, ritbon and mixtures thereof can be used. As for content, 1-20 mass parts is preferable with respect to 100 mass parts of resin (binder resin).

"Release agent"
In the present invention, it is preferable that a release agent (hereinafter also referred to as wax) is contained in the toner in order to impart an appropriate release property to the toner and prevent the occurrence of offset. The mold release agent preferably has a melting point of 40 to 150 ° C, more preferably 50 to 110 ° C.

  By having a melting point within the above range, it has been confirmed that good fixability can be obtained and good offset resistance and durability can be obtained even when the fixing temperature is set to a low temperature.

  The melting point of the release agent can be determined by differential scanning calorimetry (DSC). That is, the melting peak value when a sample of several mg is ripened at a constant rate of temperature rise, for example, (10 ° C./min) is defined as the melting point.

  Examples of the release agent that can be used in the present invention include solid paraffin wax, micro wax, rice wax, fatty acid amide wax, fatty acid wax, aliphatic monoketone, fatty acid metal salt wax, fatty acid ester wax, Partially saponified fatty acid ester wax, silicon varnish, higher alcohol, and carnauba wax are preferably used.

  In the present invention, ester compounds represented by the following general formula are particularly preferred.

R _1- (OCO-R ₂ ) n
In formula, n is an integer of 1-4, Preferably it is 2-4, More preferably, it is 3-4, More preferably, it is 4. R ₁ and R ₂ each represents a hydrocarbon group that may have a substituent. R ₁ has 1 to 40 carbon atoms, preferably 1 to 20 carbon atoms, and more preferably 2 to 5 carbon atoms. R ₂ has 1 to 40 carbon atoms, preferably 16 to 30 carbon atoms, and more preferably 18 to 26 carbon atoms.

  In the present invention, the toner may be formed by using a dispersion obtained by heating and stirring in an aqueous medium using a surfactant or a dispersant described later as a release agent. In this case, for example, it is possible to prepare a wax emulsion prepared by emulsifying a release agent, and add it together with the colorant dispersion when the resin particles are aggregated.

<Charge control agent>
The toner of the present invention may contain a charge control agent as necessary. As the charge control agent, all known ones can be used, and examples thereof include a fluorine-based activator, a salicylic acid metal salt, a metal salt of a salicylic acid derivative, and the like. Specifically, a nigrosine dye Bontron 03, a quaternary ammonium salt. Bontron P-51, azotron metal complex salt Bontron S-34, oxynaphthoic acid metal complex E-82, salicylic acid metal complex E-84, phenolic condensate E-89 (above, Orient Chemistry) Kogyo Co., Ltd.), quaternary ammonium salt molybdenum complex TP-302, TP-415 (above, manufactured by Hodogaya Chemical Co., Ltd.), quaternary ammonium salt copy charge PSY VP2038, triphenylmethane derivative copy blue PR , Quaternary ammonium salt copy charge NEGVP2036, copy charge NX VP434 ( As mentioned above, LR-901 (manufactured by Nippon Carlit Co., Ltd.), a polymer compound having a functional group such as a sulfonic acid group, a carboxyl group, a quaternary ammonium salt, and the like. It is done. Among these, azo metal complex compounds are preferable, and for example, those disclosed in paragraphs 0009 to 0012 of JP-A-2002-351150 are preferably used.

  In the present invention, the amount of charge control agent used is determined uniquely by the type of binder resin, the presence or absence of additives used as necessary, and the toner production method including the dispersion method, and is uniquely limited. Although it is not a thing, Preferably it is used in 0.1-2 mass parts with respect to 100 mass parts of binder resin. Preferably, the range of 0.2-5 mass parts is good.

  In the present invention, a charge control agent is preferably contained in the vicinity of the toner surface. That is, by containing the toner in the vicinity of the toner surface, it is possible to effectively impart chargeability to the toner and to ensure that the toner has fluidity by containing the charge control agent so as not to be exposed on the toner surface.

  As a specific content method, for example, there is a method of controlling the amount of charge control agent added to the resin particles constituting the toner. That is, a method in which a large amount of charge control agent is added to the resin particles constituting the vicinity of the toner surface and the resin particles are aggregated so that the toner surface is formed with resin particles to which no charge control agent is added, An example is a method in which resin particles containing a control agent are aggregated and then encapsulated with a resin component not containing a charge control agent on the surface of the aggregated particles.

  As a method for inclusion in the resin particles, it may be kneaded together with the binder resin, and when the dispersion diameter is adjusted or released, it may be added to the aqueous phase side and incorporated into the toner during the aggregation process or drying process.

  The toner of the present invention can be effectively produced by the following method using the above materials.

  Examples of the method for producing the toner of the present invention include a polymerization step for preparing a dispersion of resin fine particles using the radical polymerizable monomer, a resin fine particle dispersion, a colorant fine particle dispersion in an aqueous medium, and the like. , Mixing and fusing step of fusing each fine particle to obtain a toner (associating particle), filtration and washing step of removing the surfactant from the toner by filtering the toner from the toner dispersion And a drying step of drying the washed toner. Below, the outline | summary of each process is demonstrated.

(Polymerization process)
In the polymerization step, droplets of a radical polymerizable monomer solution are formed in an aqueous medium (an aqueous solution of a surfactant and a radical polymerization initiator) and emulsified in the droplets by radicals from the radical polymerization initiator. The polymerization reaction is allowed to proceed. An oil-soluble polymerization initiator may be contained in the droplet. The polymerization temperature may be any temperature as long as it is equal to or higher than the lowest radical generation temperature of the polymerization initiator, but for example, a range of 50 ° C. to 90 ° C. is used. However, it is also possible to perform polymerization at room temperature or higher by using a combination of a polymerization initiator that starts at room temperature, for example, a hydrogen peroxide-reducing agent (such as ascorbic acid).

(Salting out / fusion (meeting / fusion) process)
In the association / fusion step, the resin fine particle dispersion obtained in the polymerization step is mixed with a colorant fine particle dispersion in an aqueous medium, the fine particles are associated by salting out, and further heated to be melted. Put on. In this step, resin fine particles and colorant fine particles, as well as internal additive fine particles such as release agent fine particles and charge control agents may be fused simultaneously.

  The colorant fine particles can be prepared by dispersing the colorant in an aqueous medium. The dispersion treatment of the colorant is performed in a state where the surfactant concentration is set to a critical micelle concentration (CMC) or more in water. The disperser used for the dispersion treatment of the colorant is not particularly limited, but preferably an ultrasonic disperser, a pressure disperser such as a mechanical homogenizer or a pressure homogenizer, a medium disperser such as a sand grinder or a diamond fine mill. Can be mentioned. Examples of the surfactant used include the same surfactants as those described above.

  As a method for salting out and fusing each fine particle, a salting-out agent composed of an alkali metal salt or an alkaline earth metal salt or the like in an aqueous medium in which resin fine particles, colorant fine particles, etc. are present exceeds the critical aggregation concentration. After being added as a coagulant, it is performed by heating above the glass transition point of the resin fine particles. Examples of the salting-out agent used herein include alkali metal salts and alkaline earth metal salts. Examples of the alkali metal include lithium, potassium, and sodium, and examples of the alkaline earth metal include magnesium, calcium, strontium, and barium. Preferably, potassium, sodium, magnesium, calcium, barium and the like can be mentioned. Examples of the salt include chlorine salts, bromine salts, iodine salts, carbonates, sulfates and the like.

  The temperature range of the dispersion liquid mixture when the salting-out agent is added may be not higher than the glass transition temperature of the resin, but is generally 5 to 55 ° C, preferably 10 to 45 ° C.

(Filtering and washing process)
The filtration / washing process includes a filtration process for separating the toner from the toner dispersion obtained in the above process, and a washing process for removing the co-existing surfactant and salting-out agent from the filtered toner. Is to do. Here, examples of the filtration method include, but are not limited to, a centrifugal separation method, a vacuum filtration method using Nutsche and the like, a filtration method using a filter press and the like.

(Drying process)
The drying process is a process of drying the washed toner. Examples of dryers used in this process include spray dryers, vacuum freeze dryers, vacuum dryers, etc., stationary shelf dryers, mobile shelf dryers, fluidized bed dryers, rotary dryers A stirring dryer or the like is preferably used. The moisture of the dried toner is preferably 5% by mass or less, and more preferably 2% by mass or less. In addition, when the dried toners are aggregated by weak interparticle attractive force, the aggregates may be crushed. Here, as the crushing treatment apparatus, a mechanical crushing apparatus such as a jet mill or a Henschel mixer can be used.

(External additive mixing process)
The toner of the present invention can be used as it is, but a so-called external additive may be mixed with the toner for the purpose of improving fluidity, chargeability and cleaning properties. These external additives are not particularly limited, and various inorganic fine particles, organic fine particles and lubricants can be used.

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

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

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

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

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

  The toner of the present invention may be used as a full color toner used in a full color image forming apparatus or a monochrome toner used in a monochrome image forming apparatus, but is preferably used as a full color toner. . In full-color image forming apparatuses, the occurrence of voids due to deterioration of transferability is generally significant. However, when the toner of the present invention is used as a full-color toner, transferability is effectively reduced while maintaining good charging environment stability. This is because it can be prevented.

<Developer>
The toner of the present invention can be used as a one-component developer, a non-magnetic one-component developer, or a two-component developer.

  When used as a one-component developer, examples include a non-magnetic one-component developer or a magnetic one-component developer containing about 0.1 to 0.5 μm magnetic particles in a toner. be able to. Further, it can be mixed with a carrier and used as a two-component developer. In this case, conventionally known materials typified by iron-containing magnetic particles such as iron, ferrite, and magnetite can be used as the magnetic particles of the carrier, but ferrite particles or magnetite particles are particularly preferable. The volume average particle diameter of the carrier is preferably 15 to 100 μm, more preferably 20 to 80 μm.

  The median diameter D50 of the volume-based distribution of the carrier can be measured using a laser diffraction particle size distribution measuring device “HELOS” (manufactured by SYMPATEC).

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

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

Next, the image forming method and apparatus used in the present invention will be described. The toner of the present invention is a contact-type fixing in which a transfer material on which a toner image is formed is fixed by passing between heating members constituting a fixing device. It is suitably used for an image forming apparatus of the type.

  Hereinafter, the image forming apparatus and the fixing apparatus will be described.

  FIG. 2 is a cross-sectional view showing an example of an image forming apparatus used in the present invention.

In FIG. 2, 531 is a semiconductor laser light source , 50 is a photosensitive drum, 52 is a charger, 54 is a developing device, 58 is a transfer device, 59 is a separator (separation pole), P is a transfer material, 60 is a fixing device, 62 denotes a cleaning device, 51 denotes pre-charge exposure (PCL), and 621 denotes a cleaning blade.

The photosensitive drum 50 is formed by forming an organic photoconductor (OPC) as a photosensitive layer on the outer peripheral surface of an aluminum drum base.

In FIG. 2, exposure light is emitted from a semiconductor laser light source 531 based on information read by a document reading device (not shown). More it to polygon-mirror, distributed in a direction perpendicular to the sheet of FIG. 2, through the fθ lens for correcting the distortion of the image, making the electrostatic latent image is irradiated on the photoreceptor surface. The photosensitive drum 50 is uniformly charged by the charger 52 in advance, and starts to rotate clockwise in accordance with the timing of image exposure.

The electrostatic latent image on the surface of the photosensitive drum is developed by the developing device 54 , and the formed developed image is transferred to the transfer material P that has been conveyed in time by the action of the transfer device 58 . Further, the photosensitive drum 50 and the transfer material P are separated by a separator (separation pole) 59, but the developed image is transferred and supported on the transfer material P, guided to the fixing device 60 , fixed, and carried out of the device. The

Untransferred toner or the like remaining on the surface of the photoreceptor is cleaned by a cleaning device 62 of a cleaning blade method, the residual charge is removed by precharge exposure (PCL) 51 , and again by the charger 52 for the next image formation. Uniformly charged.

  The transfer material used in the present invention is a support for holding a toner image, and is usually called an image support, a transfer body or a transfer paper. Specifically, plain paper from thin paper to thick paper, high-quality paper, coated printing paper such as art paper and coated paper, commercially available Japanese paper and postcard paper, OHP plastic film, various transfer materials such as cloth However, it is not limited to these.

The cleaning blade 621 uses a rubber-like elastic body having a thickness of about 1 to 30 mm, and urethane rubber is most often used as the material. Since this is used in pressure contact with the photoconductor, it is easy to transfer heat. In the present invention, it is desirable to provide a release mechanism and keep it away from the photoconductor when no image forming operation is performed.

  FIG. 3 is a cross-sectional view showing an example of a fixing device (a type using a pressure roller and a heating roller) used in the present invention.

  The fixing device 10 shown in FIG. 3 includes a heating roller 71 and a pressure roller 72 in contact with the heating roller 71. In FIG. 3, reference numeral 17 denotes a toner image formed on a transfer material (transfer paper) P.

  The heating roller 71 has a coating layer 82 made of a fluororesin or an elastic body formed on the surface of the cored bar 81 and includes a heating member 75 made of a linear heater.

  The cored bar 81 is made of metal and has an inner diameter of 10 to 70 mm. Although it does not specifically limit as a metal which comprises the metal core 81, For example, metals, such as iron, aluminum, copper, or these alloys can be mentioned.

  The thickness of the cored bar 81 is 0.1 to 15 mm, and is determined in consideration of a balance between a request for energy saving (thinning) and strength (depending on the constituent materials). For example, in order to maintain the same strength as that of a cored bar made of iron of 0.57 mm with a cored bar made of aluminum, the wall thickness needs to be 0.8 mm.

  Examples of the fluororesin constituting the surface of the coating layer 82 include PTFE (polytetrafluoroethylene) and PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer).

  The thickness of the coating layer 82 made of a fluororesin is 10 to 500 μm, preferably 20 to 400 μm.

  When the thickness of the coating layer 82 made of the fluororesin is less than 10 μm, the function as the coating layer cannot be sufficiently exhibited, and the durability as the fixing device cannot be ensured. On the other hand, there is a problem that the surface of the coating layer exceeding 500 μm is easily scratched by paper dust, and toner or the like adheres to the scratched part, thereby causing image smearing.

  Further, as the elastic body constituting the covering layer 82, it is preferable to use silicon rubber, silicon sponge rubber or the like having good heat resistance such as LTV, RTV, HTV.

  The Asker C hardness of the elastic body constituting the covering layer 82 is less than 80 °, preferably less than 60 °.

  The thickness of the coating layer 82 made of an elastic body is preferably 0.1 to 30 mm, and more preferably 0.1 to 20 mm.

  As the heating member 75, a halogen heater can be preferably used.

  The pressure roller 72 is formed by forming a coating layer 84 made of an elastic body on the surface of the cored bar 83. The elastic body constituting the coating layer 84 is not particularly limited, and examples thereof include various soft rubbers such as urethane rubber and silicone rubber, and sponge rubber. The silicon rubber exemplified as the one constituting the coating layer 84 and It is preferable to use silicon sponge rubber.

  Moreover, 0.1-30 mm is preferable and, as for the thickness of the coating layer 84, 0.1-20 mm is more preferable.

  The fixing temperature (surface temperature of the heating roller 10) is preferably 70 to 210 ° C., and the fixing linear velocity is preferably 80 to 640 mm / sec. The nip width of the heating roller is set to 8 to 40 mm, preferably 11 to 30 mm.

  The heating roller may be used by applying 0.3 mg or less of silicon oil per print, but may be used without oil.

  FIG. 4 is a schematic view showing an example of a fixing device (a type using a belt and a heating roller) used in the present invention.

  The fixing device 10 shown in FIG. 4 is a type using a belt and a heating roller to secure a nip width, and is pressed against the fixing roller 601 through the fixing roller 601, the seamless belt 11, and the seamless belt 11. The pressure pad (pressure member) 12a, the pressure pad (pressure member) 12b, and the lubricant supply member 40 constitute a main part.

  The fixing roller 601 is formed by forming a heat-resistant elastic body layer 10b and a release layer (heat-resistant resin layer) 10c around a metal core (cylindrical metal core) 10a. A halogen lamp 14 is disposed as a heating source. The temperature of the surface of the fixing roller 601 is measured by the temperature sensor 15, and the halogen lamp 14 is feedback controlled by a temperature controller (not shown) based on the measurement signal, so that the surface of the fixing roller 601 is adjusted to a constant temperature. The seamless belt 11 is in contact with the fixing roller 601 so as to be wound at a predetermined angle, thereby forming a nip portion.

  Inside the seamless belt 11, a pressure pad 12 having a low friction layer on the surface is disposed in a state of being pressed against the fixing roller 601 via the seamless belt 11. The pressure pad 12 is provided with a pressure pad 12a to which a strong nip pressure is applied and a pressure pad 12b to which a weak nip pressure is applied, and is held by a holder 12c made of metal or the like.

  Further, a belt traveling guide is attached to the holder 12c so that the seamless belt 11 smoothly slides and rotates. The belt traveling guide is preferably a member having a low coefficient of friction because it rubs against the inner surface of the seamless belt 11, and a member having low heat conduction is preferable so that heat is not easily taken from the seamless belt 11. A specific example of the belt member of the seamless belt is polyimide.

  FIG. 5 is a schematic view showing an example of a fixing device (a type using a soft roller and a heating roller) used in the present invention.

  5 is a type using a soft roller and a heating roller that secures the fixing nip and prevents the transfer material from being wound and has excellent image quality. The heating roller 601 as a heating roller member, A soft roller 17 b as a roller member is used, and a halogen lamp 14 as a heating member is provided inside the heating roller 601.

  A nip portion N is formed between the heating roller 601 and the soft roller 17b, and the toner image on the transfer material P is fixed by applying heat and pressure through the nip portion N. In the above, a halogen lamp 14 (not shown) as a heating member may be disposed inside the soft roller 17b.

<Transfer material>
The transfer material used in the present invention is a support for holding a toner image, and is usually called an image support, a transfer material or transfer paper. Specifically, plain paper from thin paper to thick paper, coated printing paper such as art paper or coated paper (eg glossy coated paper), commercially available Japanese paper or postcard paper, OHP plastic film, cloth, etc. However, the present invention is not limited to these.

  The present invention will be described below with reference to examples, but the present invention is not limited thereto. In addition, the following “parts” means “parts by mass”.

<Resin particles for core>
(Preparation of resin particle 1 for core part)
As described below, first-stage polymerization, second-stage polymerization, and then third-stage polymerization were performed to prepare “resin particle 1 for core portion” having a multilayer structure.

(1) First-stage polymerization 4 parts of the anionic surfactant (1) shown below are dissolved in 3040 parts of ion-exchanged water in a 5 L separable flask equipped with a stirrer, temperature sensor, cooling pipe, and nitrogen introducing device. The prepared surfactant solution was charged, and the internal temperature was raised to 80 ° C. while stirring at a stirring speed of 230 rpm under a nitrogen stream.

(1): C ₁₀ H ₂₁ (OCH ₂ CH ₂ ) ₂ OSO ₃ Na
To this surfactant solution, an initiator solution in which 10 parts of a polymerization initiator (potassium persulfate: KPS) was dissolved in 400 parts of ion-exchanged water was added, the temperature was adjusted to 75 ° C., 532 parts of styrene, n- A monomer mixture composed of 200 parts of butyl acrylate, 68 parts of methacrylic acid and 16.4 parts of n-octyl mercaptan was added dropwise over 1 hour, and the system was polymerized by heating and stirring at 75 ° C. for 2 hours. (First stage polymerization) was performed to prepare resin particles. This is designated as “resin particle A1”.

  The “resin particles A1” prepared by the first stage polymerization had a weight average molecular weight (Mw) of 16,500.

(2) Second stage polymerization (formation of intermediate layer)
In a flask equipped with a stirrer, a monomer mixture consisting of 101.1 parts of styrene, 62.2 parts of n-butyl acrylate, 12.3 parts of methacrylic acid, and 1.75 parts of n-octyl mercaptan was released into a mold release solution. As the agent, 93.8 parts of paraffin wax “HNP-57” (manufactured by Nippon Seiki Co., Ltd.) was added, and the mixture was heated to 90 ° C. and dissolved to prepare a monomer solution.

  On the other hand, a surfactant solution in which 3 parts of an anionic surfactant (the above formula (1)) is dissolved in 1560 parts of ion-exchanged water is heated to 98 ° C., and a dispersion of resin particles A1 is added to this surfactant solution. After adding 32.8 parts of “resin particle A1” in terms of solid content, the wax monomer solution was added by a mechanical disperser “CLEAMIX” (manufactured by M Technique Co., Ltd.) having a circulation path. A dispersion liquid containing emulsified particles having a dispersed particle diameter of 340 nm was prepared by mixing and dispersing for a time.

  Next, an initiator solution prepared by dissolving 6 parts of potassium persulfate in 200 parts of ion-exchanged water was added to this dispersion, and this system was heated and stirred at 98 ° C. for 12 hours for polymerization (second stage polymerization). ) To obtain resin particles. This resin particle is referred to as “resin particle A2”. Mw of “resin particle A2” prepared by the second stage polymerization was 23,000.

(3) Third stage polymerization (formation of outer layer)
An initiator solution in which 5.45 parts of potassium persulfate is dissolved in 220 parts of ion-exchanged water is added to the “resin particles A2” obtained as described above, and styrene 293. A monomer mixed solution consisting of 8 parts, 154.1 parts of n-butyl acrylate, and 7.08 parts of n-octyl mercaptan was added dropwise over 1 hour. After completion of dropping, the mixture was heated and stirred for 2 hours to perform polymerization (third stage polymerization), and then cooled to 28 ° C. to obtain “core part resin particles 1”. Mw of “resin particle A3” prepared by the third stage polymerization was 26,800.

  The composite resin particles (resin particles) constituting the “core part resin particles 1” had a mass average particle diameter of 125 nm. The resin particles had a glass transition temperature (Tg) of 28.1 ° C. and a solubility parameter value (SP value) of 10.09.

(Preparation of core part resin particles 2)
In the preparation of “core part resin particles 1”, 271.7 parts of styrene, 173.8 parts of n-butyl acrylate, 3.5 parts of methacrylic acid, n-octyl used for the third stage polymerization (formation of outer layer) “Core part resin particles 2” were prepared in the same manner except that 7.0 parts of mercaptan and 5.4 parts of potassium persulfate were changed to an initiator solution dissolved in 210 parts of ion-exchanged water.

(Preparation of core part resin particles 3)
(1) First-stage polymerization In a 5 L separable flask equipped with a stirrer, a temperature sensor, a cooling tube, and a nitrogen introducing device, 90.8 parts of styrene, 72.7 parts of n-butyl acrylate, 12.3 parts of methacrylic acid 93.8 parts of paraffin wax “HNP-57” (manufactured by Nippon Seiki Co., Ltd.) as a release agent was added to the mixed solution of No. 1 and heated to 80 ° C. to dissolve.

  Meanwhile, a surfactant solution was prepared by dissolving 2.9 parts of an anionic surfactant (the above formula (1)) in 1340 parts of ion-exchanged water in a separable flask equipped with a stirrer, a temperature sensor, and a cooling tube. .

  After heating this surfactant solution to 80 ° C., the above polymerizable monomer solution is mixed and dispersed for 2 hours with a mechanical disperser “CLEAMIX” (manufactured by M Technique Co., Ltd.) having a circulation path, and dispersed particles. An emulsion containing emulsion particles having (245 nm) was prepared.

  Next, after adding 1460 parts of ion-exchanged water, an initiator solution prepared by dissolving 6 parts of a polymerization initiator (potassium persulfate) in 142 parts of ion-exchanged water and 1.5 parts of n-octyl mercaptan were added, After setting the temperature to 80 ° C., the system was heated and stirred at 80 ° C. for 3 hours to carry out polymerization (first stage polymerization) to prepare resin particles. This is designated as “resin particle C1”. The Mw of “resin particle C1” prepared by the first stage polymerization was 19,600.

(2) Second stage polymerization (formation of outer layer)
An initiator solution obtained by dissolving 3.8 parts of potassium persulfate in 148 parts of ion-exchanged water is added to the “resin particles C1” obtained as described above, and styrene 300. A monomer mixed solution consisting of 9 parts, 146.9 parts of n-butyl acrylate, 3 parts of methacrylic acid, and 4.93 parts of n-octyl mercaptan was added dropwise over 1 hour. After completion of the dropwise addition, the second-stage polymerization (formation of the outer layer) was performed by heating and stirring for 2 hours, and then cooled to 28 ° C. to obtain “core part resin particles 3”.

  The Mw of the polymer used for forming the outer layer in the second stage polymerization was 34,800. The mass average particle diameter of the composite resin particles constituting the “core part resin particles 3” was 137 nm. The resin particles had a Tg of 25.1 ° C. and an SP value of 10.12.

(Preparation of core part resin particles 4)
In the preparation of “core part resin particles 3”, 115.7 parts of styrene, 60.5 parts of n-butyl acrylate, 7.0 parts of n-octyl mercaptan, used in the second stage polymerization (formation of outer layer), “Core part resin particles 4” were prepared in the same manner except that 5.4 parts of potassium persulfate was changed to an initiator solution dissolved in 210 parts of ion-exchanged water.

(Preparation of core part resin particles 5)
In the preparation of the “core part resin particles 3”, 274.1 parts of styrene, 168.6 parts of n-butyl acrylate, 5.2 parts of methacrylic acid, n-type used in the second stage polymerization (formation of the outer layer). “Core part resin particles 5” were prepared in the same manner except that 6.6 parts of octyl mercaptan and 5.1 parts of potassium persulfate were changed to an initiator solution dissolved in 197 parts of ion-exchanged water.

(Preparation of core part resin particles 6)
In the preparation of “core part resin particles 3”, 202.5 parts of styrene, 211.5 parts of n-butyl acrylate, 36.0 parts of methacrylic acid, n— “Core part resin particles 6” were prepared by changing the initiator solution to 5.2 parts of octyl mercaptan and 5.1 parts of potassium persulfate dissolved in 197 parts of ion-exchanged water.

(Preparation of resin particle 7 for core part) (for comparison)
In the preparation of “core part resin particles 3”, 115.9 parts of styrene, 47.4 parts of n-butyl acrylate, 12.3 parts of methacrylic acid, n-type used in the first stage polymerization (formation of inner layer) “Core part resin particles 7” were prepared in the same manner except that the initiator solution was obtained by dissolving 1.8 parts of octyl mercaptan and 6.1 parts of potassium persulfate in 237 parts of ion-exchanged water.

(Preparation of core part resin particles 8) (for comparison)
In the preparation of “core part resin particles 3”, 270.0 parts of styrene, 153.0 parts of n-butyl acrylate, 27.0 parts of methacrylic acid, n-type used in the second stage polymerization (formation of outer layer) “Core part resin particles 8” were prepared by changing the initiator solution to 5.2 parts of octyl mercaptan and 5.1 parts of potassium persulfate dissolved in 197 parts of ion-exchanged water.

(Preparation of resin particle 9 for core part) (for comparison)
In the preparation of “core part resin particles 3”, 193.5 parts of styrene, 220.5 parts of n-butyl acrylate, 36.0 parts of methacrylic acid, n- “Core part resin particles 9” were prepared by changing to an initiator solution in which 5.8 parts of octyl mercaptan and 5.1 parts of potassium persulfate were dissolved in 197 parts of ion-exchanged water.

  Table 1 shows the physical properties of the obtained core part resin particles.

  Here, Mw (weight average molecular weight) is the weight average molecular weight of the resin particles for the core part obtained by the first stage to the third stage polymerization or the first stage to the second stage polymerization.

<< Resin particles for shell layer >>
(Preparation of resin particle 1 for shell layer)
In the first stage polymerization of the above "core part resin particles 1", styrene was changed to 624 parts, 2-ethylhexyl acrylate was changed to 120 parts, methacrylic acid was changed to 56 parts, and n-octyl mercaptan was changed to 16.4 parts. The polymerization reaction and the treatment after the reaction were performed in the same manner except that the monomer mixed solution was used to prepare “resin particle 1 for shell layer”.

(Preparation of resin particle 2 for shell layer)
In the preparation of “resin particle 1 for shell layer”, except that styrene was changed to 560 parts, 2-ethylhexyl acrylate was changed to 144 parts, methacrylic acid was changed to 96 parts, and n-octyl mercaptan was changed to 16.5 parts. Then, polymerization reaction and post-reaction treatment were performed to prepare “resin particle 2 for shell layer”.

(Preparation of resin particle 3 for shell layer)
In the preparation of “resin particle 1 for shell layer”, except that styrene was changed to 548 parts, 2-ethylhexyl acrylate was changed to 156 parts, methacrylic acid was changed to 96 parts, and n-octyl mercaptan was changed to 16.5 parts. Then, polymerization reaction and post-reaction treatment were performed to prepare “resin particle 3 for shell layer”.

(Preparation of resin particle 4 for shell layer)
In preparation of “resin particle 1 for shell layer”, except that styrene was changed to 585.6 parts, 2-ethylhexyl acrylate was 138.4 parts, methacrylic acid was 56 parts, and n-octyl mercaptan was changed to 16.5 parts. Then, the polymerization reaction and the post-reaction treatment were performed to prepare “resin particle 4 for shell layer”.

(Preparation of resin particle 5 for shell layer)
In the preparation of “resin particle 1 for shell layer”, 140 parts of styrene, 400 parts of methyl methacrylate, 240 parts of 2-ethylhexyl methacrylate, 20 parts of methacrylic acid,
Except having changed n-octyl mercaptan into 16.5 parts, the polymerization reaction and the process after reaction were performed similarly and the "resin particle 5 for shell layers" was prepared.

(Preparation of resin particle 6 for shell layer)
In the preparation of “shell layer resin particles 1”, 144 parts of styrene, 400 parts of methyl methacrylate, 240 parts of 2-ethylhexyl methacrylate,
Polymerization reaction and post-reaction treatment were performed in the same manner except that 56 parts of methacrylic acid was changed to 16 parts of itaconic acid and n-octyl mercaptan was changed to 8.0 parts to prepare “resin particle 6 for shell layer”.

(Preparation of resin particle 7 for shell layer) (for comparison)
In preparation of “shell layer resin particle 1”, styrene was changed to 414 parts, 2-ethylhexyl acrylate 120 parts changed to n-butyl acrylate 331 parts, methacrylic acid changed to 56 parts, and n-octyl mercaptan changed to 16.5 parts. In the same manner as described above, polymerization reaction and post-reaction treatment were performed to prepare “resin particle 7 for shell layer”.

(Preparation of shell layer resin particles 8 (for comparison))
In the preparation of “resin particle 1 for shell layer”, except that 464 parts of styrene, 240 parts of 2-ethylhexyl acrylate, 96 parts of methacrylic acid, and 14.5 parts of n-octyl mercaptan were changed, Polymerization reaction and post-reaction treatment were performed to prepare “resin particle 8 for shell layer”.

  Table 2 shows the physical properties of the obtained resin particles for the shell layer.

<Production of toner>
Toners 1 to 15 were produced as follows.

<Preparation of Toner 1>
(Preparation of dispersion 1 of colorant particles)
90 parts of the anionic surfactant (1) was dissolved in 1600 parts of ion-exchanged water with stirring. While stirring this solution, 400 parts of carbon black “Regal 330” (manufactured by Cabot) is gradually added, and then dispersed using a stirrer “Clearmix” (manufactured by MTechnic Co., Ltd.). Agent particle dispersion 1 "was prepared.

  The particle diameter of the colorant particles in this “colorant particle dispersion liquid 1” was 110 nm as measured using an electrophoretic light scatterometer (ELS-800: manufactured by Otsuka Electronics Co., Ltd.).

(Salting out / fusion (association / fusion) process) (core formation)
420.7 parts (in terms of solid content) of “core part resin particles 1”, 900 parts of ion-exchanged water, and 200 parts of “colorant particle dispersion 1” were added to a temperature sensor, a cooling pipe, a nitrogen introducing device, It stirred in the reaction container (four-necked flask) which attached the stirring apparatus. After adjusting the temperature in the container to 30 ° C., a 5 mol / liter sodium hydroxide aqueous solution was added to this solution to adjust the pH to 8-11.

Next, an aqueous solution in which 2 parts of magnesium chloride hexahydrate was dissolved in 1000 parts of ion-exchanged water was added over 10 minutes at 30 ° C. with stirring. After standing for 3 minutes, temperature increase was started, and the system was heated to 70 ° C. over 60 minutes. In this state, the particle size of the associated particles was measured with “Coulter Counter TA-II” (manufactured by Coulter Co.). When the median diameter (D ₅₀ ) of the particles reached 5.5 μm, 40.2 parts of sodium chloride was used. An aqueous solution in which 1000 parts of ion-exchanged water is dissolved is added to stop the growth of the particle size, and further, the fusion is continued by heating and stirring at a liquid temperature of 70 ° C. for 1 hour as an aging treatment. Formed.

(Shelling operation) (Formation of shell layer)
Next, 96 parts of “shell layer resin particles 3” were added while gradually raising the temperature from 70 ° C. to 80 ° C., and stirring was continued for 1 hour. After fusing the particles of “Particle 3”, an aging treatment was performed at 80 ° C. for 20 minutes to form a shell layer.

  Here, 40.2 parts of sodium chloride was added, cooled to 30 ° C. under the condition of 8 ° C./min, and the generated fused particles were filtered and repeatedly washed with 45 ° C. ion-exchanged water. By drying with warm air, “Toner 1” having a shell layer on the surface of the core portion was obtained.

  The circularity was measured in a water dispersion system using a flow particle image analyzer “FPIA-2000” (manufactured by Sysmex Corporation).

  For the glass transition temperature (Tg), a differential scanning calorimeter “DSC-200” (manufactured by Seiko Denshi Co., Ltd.) was used, and a 10 mg sample to be measured was precisely weighed and placed in an aluminum pan. , And after raising the temperature from room temperature to 200 ° C. at a temperature rising rate of 30 ° C./min, this was cooled and measured between 10 and 120 ° C. at a temperature rising rate of 10 ° C./min. The shoulder value of the main endothermic peak in the range of 20 to 90 ° C. during this temperature rising process was taken as the glass transition point.

The weight average molecular weight was measured using gel permeation chromatography “807-1T type” (manufactured by JASCO Corporation). While maintaining the column temperature at 40 ° C., tetrahydrofuran as a carrier solvent was flowed at 1 kg / cm ² , 30 mg of a sample to be measured was dissolved in 20 ml of tetrahydrofuran, 0.5 mg of this solution was introduced into the apparatus together with the carrier solvent, It calculated | required by polystyrene conversion. The film thickness and SP value of the shell layer were measured by the above methods.

<Preparation of Toner 2-15>
The “core part resin particles 1” and “shell layer resin particles 3” used in the production of “toner 1” are used as the core part resin particles shown in Table 1 and the shell layer resin particles shown in Table 2, respectively. “Toners 2 to 15” were produced in the same manner except for the change.

  Table 3 shows the values of Tg1, Tg2, and Tg2-Tg1 of the toner.

  Table 4 shows the physical property values of the toner.

<< External additive treatment process >>
1% by weight of hydrophobic silica (number average primary particle size = 12 nm, degree of hydrophobicity = 68) and hydrophobic titanium oxide (number average primary particle size = 20 nm, hydrophobic) 1.2% by mass was added and mixed with a Henschel mixer to prepare “Toners 1 to 15”. “Toners 1 to 11” of the obtained toner are referred to as “Examples 1 to 11”, and “Toners 12 to 15” are referred to as “Comparative Examples 1 to 4”.

<< Preparation of developer >>
Next, a ferrite carrier having a volume average particle size of 50 μm coated with a silicone resin was mixed with each of the prepared toners to prepare “Developers 1 to 15” having a toner concentration of 6%.

<Evaluation>
The following evaluation was performed using “Examples 1 to 11” and “Comparative Examples 1 to 4” produced above. In addition, ◎ and ○ of the evaluation criteria are passed and × is rejected.

<Creating a print image>
The printed image is fixed using a commercially available multifunction machine “Satios9331” (manufactured by Konica Minolta Business Technology Co., Ltd.) that employs a print image electrophotographic method, the linear speed is 280 mm (about 50 sheets / min), and the developing roller is fixed to Φ9 mm The device was changed to a fixing device (type using a belt and a heating roller) having the configuration shown in FIG. 4, and printing was performed to create a printed image. The following items were evaluated for the state of the multifunction device and the print image.

(Charging speed)
The charging speed was evaluated by the charge rising when the toner was supplied to the developing device. Specifically, using a manuscript with a pixel ratio of 75% and a large image portion, printing 1000 sheets in a print mode in which toner consumption (supply amount) is remarkably large, and after 1000 sheets are printed, the toner in the machine due to charging rise failure The stain due to scattering and the image fading of the printed image were visually evaluated.

Evaluation criteria ◎: No toner stains in the machine and no smearing of the print image ○: No toner stains in the machine, but slight fading occurred at the rear end of the print image No problem in practical use ×: Toner stains in the machine There is a problem in practical use due to faint print image.

(Image retention)
The image retention was evaluated by visual evaluation of the printed image after putting the developer left in high temperature and high humidity (30 ° C., 90% RH) for 72 hours into the developing device for printing. A document having a photographic image, characters, and a halftone image was used.

Evaluation Criteria A: Gradation variation is not visually confirmed. O: Light color (halftone), photographic image feels dark but no problem for practical use.

<Heat resistant storage>
The heat-resistant storage property is that the amount of agglomerates remaining on the sieve after 100 g of each of the toners prepared above was left for 24 hours under conditions of 55 ° C. and 90% RH and then sieved with a sieve having an opening of 45 μm. It was evaluated with.

Evaluation Criteria A: Less than 5% on the sieve, very little aggregation, excellent heat-resistant storage (no heat generation packing material, no aggregates even if transported in summer)
○: The amount on the sieve is 5 to 30% and the amount of agglomeration is small and the heat-resistant storage property is good (there is no occurrence of agglomerates even if transported in the summer with cardboard packaging only)
X: The amount on the sieve is more than 30%, the amount of aggregation is large, and there is a problem in practical use (need to carry out cold transport).

<Minimum fixing temperature>
The surface temperature of the heating roller of the fixing device of the evaluation machine was changed so that the paper surface temperature was changed in increments of 10 ° C. within the range of 80 to 150 ° C., and the toner image was fixed at each changed temperature to produce a fixed image. . In producing the print image, high-quality paper (80 g / m ² ) of A4 size was used.

  The fixing strength of the printed image obtained by fixing is fixed using a method in accordance with the mending tape peeling method described in Chapter 9 Section 1.4 of “Basics and Applications of Electrophotographic Technology: Electrophotographic Society”. The rate was evaluated.

Specifically, after a 2.54 cm square solid black print image with a toner adhesion amount of 0.6 mg / cm ² was prepared, images before and after peeling with “Scotch Mending Tape” (manufactured by Sumitomo 3M) The density was measured, and the residual ratio of the image density was determined as the fixing ratio.

  The “transfer material (paper) surface temperature” at which the fixing rate is 95% or more is defined as the minimum fixing temperature. The surface temperature of the transfer material (paper) was measured with a non-contact thermometer. The image density was measured with a reflection densitometer “RD-918” (manufactured by Macbeth).

Evaluation criteria A: Fixing is possible at a minimum fixing temperature of less than 100 ° C. ○: Fixing is possible at a minimum fixing temperature of 100 ° C. or more and less than 130 ° C. ×: Fixing is possible at a minimum fixing temperature of 130 ° C. or more.

<Fixing wrinkles on thin paper>
Using 40 g / m ² of thin paper as a transfer material, 20 print originals (A4 version) having a solid image were printed out. The evaluation of fixing wrinkles was performed based on the number of wrinkles generated during fixing.

Evaluation Criteria A: Wrinkle was not generated in 20 prints. ○: Wrinkle was generated in 2 prints or less in 20 prints. X: Wrinkles were generated in 2 prints in more than 2 prints. .

<Glossy coated paper image defects>
Glossy coated paper (manufactured by Mitsubishi Paper Industries Co., Ltd., Tokishi Art, 75 g / m ² ) was used as a transfer material, and 20 printed originals (A4 version) having solid images were printed out. The white spot having a diameter of 1 mm or more in the solid image was visually counted, and the image defect of the glossy coated paper was evaluated by the number of white spots.

Evaluation criteria A: There was no white spot missing in the solid image. ○: There were 1 to 3 average white spot missing of 1 mm or more in the solid image. X: White spot missing of 1 mm or more in the solid image. There were more than 3 on average.

  Table 5 shows the evaluation results.

  As is clear from the evaluation results of Table 5, “Examples 1 to 11” are excellent in all evaluation items, but “Comparative Examples 1 to 4” have problems in at least any of the evaluation items. .

FIG. 3 is a schematic diagram showing a structure of a toner of the present invention. It is sectional drawing which shows an example of the image forming apparatus used by this invention. It is sectional drawing which shows an example of the fixing device (type using a pressure roller and a heating roller) used by this invention. It is the schematic which shows an example of the fixing device (type using a belt and a heating roller) used by this invention. It is the schematic which shows an example of the fixing device (type using a soft roller and a heating roller) used by this invention.

Explanation of symbols

T toner A core B shell layer 1 colorant particle 2 resin A
3 Resin B

Claims (10)

In the electrostatic charge image developing toner having a core-shell structure in which a shell layer containing resin B is coated on the surface of the core part containing resin A and a colorant,
When the glass transition temperature of the resin A is Tg1 and the glass transition temperature of the resin B is Tg2, Tg2-Tg1 ≧ 25 ° C., 10 ° C. ≦ Tg1 ≦ 30 ° C. , 50 ° C. ≦ Tg2 ≦ 65 ° C.
When the solubility parameter value of the resin A is SP1 and the solubility parameter value of the resin B is SP2, the difference (ΔSP) between SP1 and SP2 is 0.2 to 1.0,
The toner for developing an electrostatic charge image is obtained by salting out / fusing resin particles containing resin B on the surface of a core part containing resin A and a colorant to form a shell layer. An electrostatic charge image developing toner. The electrostatic image developing toner according to claim 1, wherein the resin A and the resin B are styrene-acrylic copolymer resins . Toner, toner according to claim 1 or 2 you, characterized in that it contains a colorant 20 parts per 100 parts of resin. The electrostatic charge image developing toner according to claim 1 , wherein the toner has a circularity of 0.94 to 0.99 . Toner of the thickness of the shell layer, an electrostatic charge image developing toner according to any one of claims 1 to 4, characterized in 10~500nm der Rukoto. The weight average molecular weight of the resin A is, claim 1 electrostatic image developing toner according to any one of 4, which is a 5,000 to 30,000. The electrostatic image developing toner according to any one of claims 1 to 4 , wherein the resin B has a weight average molecular weight of 10,000 to 80,000 . In the method for producing a toner for developing an electrostatic charge image having a core-shell structure in which a shell layer containing resin B is coated on the surface of a core part containing resin A and a colorant,
When the glass transition temperature of the resin A is Tg1 and the glass transition temperature of the resin B is Tg2, Tg2-Tg1 ≧ 25 ° C., 10 ° C. ≦ Tg1 ≦ 30 ° C., 50 ° C. ≦ Tg2 ≦ 65 ° C.
When the solubility parameter value of the resin A is SP1 and the solubility parameter value of the resin B is SP2, the difference (ΔSP) between SP1 and SP2 is 0.2 to 1.0,
Production of an electrostatic charge image developing toner comprising a step of salting out / fusing resin particles containing resin B on the surface of a core containing resin A and a colorant to form a shell layer Way . Step of forming a shell layer by salting out / fusion of resin particles containing resin B on the surface of the core obtained by salting out / fusion of resin particles containing resin A and colorant particles The method for producing a toner for developing an electrostatic charge image according to claim 8 , comprising : 10. The method for producing a toner for developing an electrostatic charge image according to claim 8, wherein the resin particles containing the resin A are composite resin particles obtained by a multistage polymerization method.

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