JP2006023720A - Toner, and manufacturing method of toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner which can produce a strongly and beautifully finished toner image as print-on-demand by using paper for printing even when the image forming is carried out at a low fixing temperature, and which has a stable performance that does not agglomerate even after a long-term storage. <P>SOLUTION: The toner has a binder resin constituted of a plurality of kinds of copolymers of vinyl-based polymeric monomers. At least one kind of the plurality of kinds of copolymers of vinyl-based polymeric monomers is formed by using a monomer having two or more polar groups. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a toner that can fix a toner image at a low temperature used in printers, copiers, facsimiles, and the like, and a toner manufacturing method.

  In the field of electrophotographic technology such as copiers and printers, with the advancement of digital technology, minute dot images of 1200 dpi (dpi stands for the number of dots per inch, that is, 2.54 cm) have recently been accurately obtained. Therefore, high-definition and high-resolution image formation is required. In order to realize such high-definition and high-resolution image formation, toner particle size is also being reduced. For example, the development of technology for reducing particle size by chemical toner represented by polymerized toner There is something remarkable.

  By the way, as the particle size of the toner is reduced, the toner particles tend to vary in chargeability. There is a toner technique in which a polyester resin is prepared from a polyvalent carboxylic acid or a polyhydric alcohol contained therein (see, for example, Patent Document 1).

  On the other hand, from the viewpoint of energy saving, development of a toner that can be fixed at a low temperature has been studied. For example, by using a vinyl-based copolymer having an acid group and a hydroxyl group as a binder resin, by performing molecular weight distribution or forming a crosslinked structure, or by designing a resin with a molecular chain structure according to the molecular weight And development of a toner that exhibits low-temperature fixability (see, for example, Patent Document 2).

  In addition, low-temperature fixing can be performed using a binder resin composed of a urethane-modified polyol resin using polyisocyanate and a styrene copolymer resin having an acrylic acid ester monomer or a methacrylic acid monomer as a structural unit. Development of a toner that can be realized is mentioned (for example, see Patent Document 3).

  By the way, there has been a need for energy saving for an image forming apparatus, but a higher need has recently been demanded.

  This can be attributed to the fact that the usage of copiers and printers has recently changed significantly. For example, in offices, several printers are connected to the LAN for each workplace, and reducing the power consumption of individual printers reduces the comfort of the workplace environment and power costs. It has become a very important issue from the viewpoint of preventing global warming.

  As described above, from the viewpoint of energy saving and the user's work environment, and thus the global environment, there is a demand for a toner that exhibits stable fixing performance at a low temperature, but it is stable at a low temperature (for example, below the boiling point of water). In order to enable fixing, the glass transition temperature of the resin must be set low.

  However, if the glass transition temperature of the resin is set low, the toner particles tend to adhere and aggregate when stored for a long period of time, making it difficult to develop stable storage performance.

  Also, if the binder resin or release agent contained in the toner contains a material that exhibits crystallinity, it is assumed that crystallization proceeds even at a low temperature, but the glossiness of the image is reduced. Occurrence of gloss and unevenness was observed, which hindered the formation of a beautifully finished printed image.

  Accordingly, the toner for low-temperature fixing is required to have not only fixing performance but also storage stability that does not aggregate even after long-term storage. Furthermore, it has been required to form a toner image having a beautiful finish without unevenness as well as the formed toner image.

  Recently, electrophotographic image technology is also attracting attention in the field of light printing due to the fact that there is no hassle of creating plates, and print-on that provides only the number of books needed for small orders.・ It is also developed in demand type image forming system.

In such a printing field, the types of paper used for image formation are greatly increased compared to those used in conventional copying machines and printers, and toner images can be formed on all types of paper. Required. However, it has been difficult to stably form toner images on all types of paper with current toners. Further, since the temperature at the time of fixing has a considerable influence on the fibers constituting the paper, even when developing in the field of light printing, the advent of toner that can be fixed at a lower temperature has been awaited.
Japanese Patent Laid-Open No. 2003-5441 JP 2003-57877 A JP 2004-20575 A

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a toner capable of eliminating the influence of an environmental load caused by use of an electrophotographic image forming apparatus such as a copying machine, a printer, and a facsimile. To do. Specifically, the toner image can be fixed at a temperature lower than that achieved in the prior art, and stable performance can be achieved without the toner particles adhering and agglomerating even after long-term storage. It is an object to provide a reliable toner.

  Further, the present invention creates a beautifully finished printed image having a strength that prevents the fixed toner image from being peeled off even when the toner image is fixed at a low fixing temperature, and has a uniform glossiness without unevenness. It is an object to provide a toner that can be used.

  It is another object of the present invention to provide a toner capable of forming a stable image on a paper type, such as coated paper, thick paper, or thin paper, which has been very difficult to form with a conventional technique. It is. In other words, by increasing the number of paper types on which toner images can be formed, printing can be performed without causing a plate in the field of light printing, and when necessary, only the required number of copies can be created. An object is to provide a toner capable of forming an image.

  The object of the present invention is achieved by adopting the following configuration.

(Claim 1)
A toner comprising a binder resin composed of a copolymer of a plurality of types of vinyl polymerizable monomers, wherein at least one of the copolymers of the plurality of types of vinyl polymerizable monomers is A toner formed using a monomer having two or more polar groups.

(Claim 2)
The toner according to claim 1, wherein the binder resin has a region having a low glass transition temperature.

(Claim 3)
The toner according to claim 1, wherein the region having a low glass transition temperature exists as an independent phase of 50 to 600 nm in the binder resin.

(Claim 4)
The region having a low glass transition temperature is formed by a vinyl copolymer formed using a monomer having two or more polar groups. The toner according to claim 1.

(Claim 5)
The proportion of the vinyl copolymer formed using a monomer having two or more polar groups is 3 to 20% by mass with respect to the total mass of the binder resin. 5. The toner according to any one of 4 above.

(Claim 6)
6. The toner according to claim 1, wherein the binder resin has a peak molecular weight in the range of 15000 to 25000 and 25000 to 35000, respectively.

(Claim 7)
The toner according to claim 1, wherein the binder resin contains a vinyl copolymer having a dicarboxylic acid monomer as a copolymer component.

(Claim 8)
A toner production method for producing a toner through a step of aggregating a plurality of types of vinyl copolymer particles to form a binder resin, wherein at least one of the plurality of types of vinyl copolymer particles is polar Particles formed using a monomer having two or more groups, and in the step of aggregating the vinyl copolymer particles, particles formed using a monomer having two or more polar groups A method for producing a toner, characterized in that after aggregating each other, other particles agglomerate to form a binder resin.

(Claim 9)
The toner production according to claim 8, wherein the vinyl copolymer particles formed using a monomer having two or more polar groups are formed using a dicarboxylic acid monomer. Method.

(Claim 10)
The glass transition temperature of vinyl copolymer particles formed using a monomer having two or more polar groups is lower than the glass transition temperature of other vinyl copolymer particles. Item 10. The toner production method according to Item 8 or 9.

(Claim 11)
The vinyl copolymer particles formed using the monomer having two or more polar groups and the other vinyl copolymer particles have a difference in solubility parameter value of 0.3 to 1.2. The method for producing a toner according to any one of claims 8 to 10, wherein:

  According to the present invention, a toner in which a plurality of types of vinyl copolymer particles are aggregated to form a binder resin can fix a toner image at an extremely low temperature that could not be achieved with conventional toners. In addition, it has been found that even when stored for a long period of time, toner particles adhere to each other and do not aggregate and exhibit stable storage performance.

  As a result, by using the toner according to the present invention, it is possible to realize a significant energy saving of the image forming apparatus. For example, as in a recent office, a plurality of units can be connected in one workplace by LAN connection. Even when using a copier or printer, the power consumption can be greatly reduced, and a comfortable operating environment can be provided to the user even in places where restrictions are placed on the installation space, such as in private stores and general households. I was able to provide it.

  In addition, by providing stable storage performance, we provide a highly economical toner that does not cause an increase in costs such as capital investment to maintain toner performance during toner product storage and distribution processes. I can do it now.

  Further, it has become possible to provide a toner capable of obtaining a beautifully finished printed image having uniform glossiness even when image formation is performed at a low fixing temperature.

  Furthermore, according to the present invention, stable toner image formation can be performed even on paper types such as thick paper, coated paper, and thin paper, which have conventionally been difficult to perform image formation using toner. That is, in the present invention, the range of selection of paper types that can be used for image formation has been expanded, and printing that has been performed by light printing can be performed by an electrophotographic system. As a result, it was possible to create the required number of printed materials without the hassle of making a plate, making it possible to speed up bookbinding operations including light printing and reduce costs.

  As described above, according to the present invention, it is possible to stably form an image at a low fixing temperature, which has been difficult to realize with conventional toners.

  The inventors of the present invention can perform fixing at a low temperature, and can be quickly melted with a small amount of heat at the time of fixing, and at the same time have the performance that toner particles do not adhere and aggregate even when stored for a long period of time. We examined the development of a satisfactory toner.

  As a result, with respect to the binder resin constituting the toner, the effect of the present invention is achieved by the toner having a structure as shown in FIG. 1 described later formed by associating resin particles having an amorphous (non-crystalline) structure. Was found to be expressed.

  By manufacturing such a toner, fixing at a low temperature, which could not be achieved by the prior art, can be performed completely oilless. For example, a toner image can be obtained even at a low temperature below the boiling point of water. It was confirmed that a toner capable of stably fixing the toner was obtained.

  FIG. 1 is a schematic view of toner particles according to the present invention.

  In FIG. 1, the toner particles T have a structure including a resin phase B in a resin phase A. In the toner particles T according to the present invention, the glass transition temperature of the resin forming the resin phase B is lower than the glass transition temperature of the resin forming the resin phase A.

  In the present invention, in the toner particle production process, the step of associating amorphous (non-crystalline) resin particles having a solubility parameter (SP value) difference of 0.3 to 1.2 from each other is performed. Through this, toner particles having a binder resin having such a structure can be formed.

  In the present invention, when agglomeration is performed using resin particles formed using monomers having at least one kind of two or more polar groups, a toner made of a binder resin having a structure as shown in FIG. 1 is obtained. I found out that

  As described above, an amorphous resin is composed of a resin phase A and a resin phase B as shown in FIG. 1 by aggregating resin particles formed using a monomer having two or more polar groups. This is probably because the difference in the polar group concentration of each resin particle acts and the probability that the resin A having a low aggregation rate is arranged outside the resin B is increased.

  That is, the resin particles having two or more polar groups are preferentially aggregated during the aggregation by the action of the polar groups, and after the aggregation is completed, the remaining resin particles are aggregated to form the resin phase B in the resin phase A. It is presumed to form an enclosing structure.

  Further, in the present invention, toner particles having a structure in which the resin phase A is included in the resin phase A composed of mutually incompatible resins, the low level that could not be achieved by the conventional techniques. It enables both fixing at temperature and stable storage performance. In other words, the fixing temperature can be set lower by lowering the glass transition temperature of the resin constituting the resin phase B, and the resin phase B having a lower glass transition temperature is included in the toner particles. As a result, the toner particles are less likely to aggregate. In the present invention, by using toner particles having a structure in which the resin phase A is included in the resin phase A with an incompatible amorphous resin, for example, at a temperature similar to the boiling point of water. It was found that it can be established.

  In addition, with the toner according to the present invention, it becomes possible to easily form a toner image on coated paper or cardboard, which has conventionally been difficult to form an image with toner, greatly increasing the types of paper on which image formation is possible. I was able to increase it. The reason why the number of papers capable of forming a toner image can be increased in this way is probably due to the presence of a resin formed using a monomer having two or more polar groups. Guessed. In other words, the presence of polar groups in the resin increases the affinity between the toner particles and the recording paper, so that a stable affinity can be obtained even with the coated paper, which is difficult to obtain with conventional toners. It is presumed that it was possible to express.

  As a result, according to the toner of the present invention, a toner image can be stably formed on coated paper, cardboard, etc., so that the electrophotographic system can be used in the image forming field that has been limited to printing. The image forming method can be developed. In particular, in the field of light printing, where there are many small print orders, it has become possible to create a print-on-demand document that prints out the required number of copies when necessary without causing a plate.

  The toner according to the present invention will be described in more detail.

  The toner particles according to the present invention are composed of a plurality of types of amorphous resins that are incompatible with each other, and have a structure composed of a resin phase A and a resin phase B shown in FIG. In particular, the resin forming the resin phase B is formed using a vinyl-based monomer having two or more polar groups, and the resin phase A formed using incompatible amorphous resin particles. And toner particles having a structure consisting of the resin phase B.

  Here, the monomer having two or more polar groups means a monomer having a functional group such as a carboxyl group or a hydroxyl group in the side chain of the vinyl monomer. Those having a glass transition temperature of 50 ° C. or lower when formed are preferred.

  As the binder resin used in the present invention, an amorphous vinyl copolymer is preferably used. By using a resin having an amorphous structure as a binder resin, it becomes possible to quickly melt the toner at the time of fixing, adhere to the recording paper, and solidify, which is preferable in promoting the speed of image formation. Is. In this invention, the vinyl-type copolymer used as an amorphous state is obtained by producing resin using the monomer mentioned later.

  As a method for confirming that the binder resin used in the present invention has an amorphous structure, measurement of heat of fusion, X-ray diffraction method, nuclear magnetic resonance spectrum (NMR) method, etc. A measuring method is mentioned.

  In the present invention, toner particles having a structure composed of a resin phase A and a resin phase B as shown in FIG. 1 are formed by using a plurality of types of amorphous resins. The resin forming B needs to have incompatible properties with each other.

  And in this invention, in order to form the resin phase which has the structure which included the resin phase B in the resin phase A, when forming the resin phase B, the resin particle is used using the monomer which has two or more polar groups mentioned above Form.

  A monomer having two or more polar groups forming the resin constituting the resin phase B (hereinafter also referred to as a polymerizable monomer) will be described.

  The polar group referred to in the present invention has a dissociation property in an aqueous medium and forms a salt. Specific examples include a carboxyl group, a sulfone group, an amino group, and an ammonium group.

  Examples of the monomer having two or more polar groups that can be used in the present invention include those containing a carboxyl group such as itaconic acid and maleic acid.

  Among these monomers, those having a glass transition temperature of 50 ° C. or lower when the resin of the resin phase B is formed are preferable.

  Further, in the present invention, when preparing the resin particles constituting the resin phase B, as a monomer having two or more polar groups as described above, 2 carboxyl groups are particularly present in the molecule such as itaconic acid and maleic acid. When resin particles are formed using a monomer containing one or more monomers (in the present invention, such a carboxyl group-containing monomer is referred to as a dicarboxylic acid monomer), the structure shown in FIG. It has been confirmed that resin formation is promoted.

  In the present invention, toner particles using resin particles formed using monomers containing two or more carboxyl groups such as itaconic acid or maleic acid among the monomers containing polar groups described above are the present invention. It has been confirmed that this is particularly preferable as an effect.

  In addition to the above, the polar group in these monomers may have an acid anhydride, acid chloride, or metal salt form. These are preferably used together with 2-ethylhexyl acrylate or 2-ethylhexyl methacrylate because the solubility parameter value (SP value) can be easily controlled.

  In the present invention, the monomer forming the resin constituting the resin phase B is used in combination with a monomer having two or more polar groups as described above and a monomer such as a styrene monomer described later. It may be one that forms a copolymer resin.

  As a specific example of the resin constituting the resin phase B, the present invention is not limited to this, but, for example, 35 to 50% by mass of styrene as a monomer, and 30 to 50 of 2-ethylhexyl acrylate. Examples thereof include vinyl copolymers formed by polymerizing mass%, itaconic acid or maleic acid at a ratio of 15 to 20 mass%.

  Next, the monomer that forms the resin constituting the resin phase A will be described.

  In the present invention, examples of the monomer forming the resin constituting the resin phase A include vinyl aromatic monomers, vinyl ester monomers, vinyl ether monomers, monoolefin monomers, and the like. Is mentioned.

  Examples of vinyl aromatic monomers include styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, p-methoxy styrene, p-phenyl styrene, p-ethyl styrene, pn-butyl styrene, p. -Tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, 2,4-dimethyl styrene, 3, Examples thereof include styrene monomers such as 4-dichlorostyrene and derivatives thereof.

  Examples of vinyl ester monomers include vinyl acetate, vinyl propionate, vinyl benzoate, etc., and examples of vinyl ether monomers include vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, vinyl phenyl ether, and the like. Can be mentioned.

  Examples of monoolefin monomers include ethylene, propylene, isobutylene, 1-butene, 1-pentene, 4-methyl-1-pentene, and examples of diolefin monomers include butadiene, isoprene, chloroprene, and the like. Is mentioned.

  Among these, as a monomer forming the resin constituting the resin phase A, a styrene monomer or a monomer mixture obtained by mixing a styrene monomer and another copolymerizable monomer is used. The amount of the styrene monomer is preferably 50% by mass or more based on the total amount of the monomers.

  Examples of the styrene monomer include styrene and p-methylstyrene.

  Other copolymerizable monomers used together with the styrene monomer include acrylic acid ester monomers such as ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate; methyl methacrylate, methacryl Methacrylic acid ester monomers such as ethyl acetate and butyl methacrylate; Alkyl vinyl ethers such as methyl vinyl ether; Vinyl ester monomers such as vinyl acetate and vinyl butyrate; N-methyl acrylamide and N-ethyl acrylamide Examples thereof include alkyl-substituted acrylamides; nitrile monomers such as acrylonitrile and methacrylonitrile; polyfunctional monomers such as divinylbenzene, ethylene glycol (meth) acrylate, and trimethylolpropane tri (meth) acrylate.

  Moreover, as a monomer which forms the resin phase A, what has two or more unsaturated bonds, such as divinylbenzene, divinylnaphthalene, divinyl ether, ethylene glycol dimethacrylate, polyethyleneglycol dimethacrylate, is a crosslinkable monomer It can also be used.

  By using a crosslinkable monomer, it becomes difficult to give regularity and synchronism to the structure of the polymer chain constituting the binder resin, so that it becomes easier to obtain an amorphous structure resin and between the polymer chains. It is possible to improve the strength of the resin without significantly increasing the binding energy. As a result, fixing at a low temperature is possible and, for example, the durability of the toner can be improved without being destroyed even if the stirring in the developing device is repeated.

The binder resin used in the present invention is composed of a plurality of types of vinyl copolymers, and these vinyl copolymers are all amorphous and are incompatible with each other. Have a relationship. The binder resin used in the present invention preferably has one or more of the following characteristics. That is,
(1) The size of the resin phase B is 50 to 600 nm. (2) The glass transition temperature of the resin constituting the resin phase B is 50 ° C. or less, and the glass transition temperature of the resin constituting the resin phase A is 70. (3) The solubility parameter value (SP value) of the resin constituting the resin phase B is 9.5 to 10.0, and the solubility parameter value (SP value) of the resin constituting the resin phase A is (4) The binder resin has peaks in the molecular weight ranges of 15,000 to 25,000 and 25,000 to 35,000. (5) The binder resin. The ratio of the low molecular weight component (molecular weight is 5,000 or less) is 20% by mass or less. The above features will be specifically described below.

  The binder resin used in the toner of the present invention is formed by aggregating amorphous vinyl copolymer particles having an incompatible relationship with each other.

  Specifically, the toner particles having the structure shown in FIG. 1 are vinyl particles formed using a vinyl copolymer resin particle constituting the resin phase A and a monomer having two or more polar groups. The resin particles (resin particles constituting the resin phase B) of the copolymer are prepared, and the resin particles are obtained by aggregating these resin particles.

  In the present invention, when resin particles are aggregated, toner particles having the structure shown in FIG. 1 can be formed even if resin particles having different structures are mixed. Thus, although the reason why the binder resin can form the structure shown in FIG. 1 is not clear, the resin particles formed using the monomer having two or more polar groups described above are probably It is presumed that, due to the action of the polar group, the resin particles having two or more polar groups are preferentially aggregated in the aggregation step, and then the remaining resin is aggregated.

  In the present invention, when the ratio of the resin prepared using the monomer having two or more polar groups is 3 to 20% by mass, preferably 5 to 15% by mass, based on the total mass of the binder resin. Further, it is confirmed that toner particles having a structure as shown in FIG. 1 are obtained, and the size of the resin phase B is 50 to 600 nm.

  It can be confirmed that the binder resin used in the present invention has such a structure by observing a toner particle section stained with an osmium compound or the like with a transmission electron microscope (TEM).

  The transmission electron microscope apparatus (TEM) that can observe the structure of the toner particles is preferably a model that can be observed at an acceleration voltage of 80 kV or less. Specifically, "S-5000H" (made by Hitachi, Ltd.), "JEM-200FX" (made by JEOL Ltd.), etc. are mentioned. In the present invention, the size of the resin phase B in the toner particles is calculated from the projection surface of ten or more toner particles photographed at a magnification of 10,000 times.

  The photographing method using a transmission electron microscope is performed by a generally known method performed when measuring toner particles.

  That is, the observation and measurement of the toner particle cross section are specifically performed by the following method. First, toner particles are sufficiently dispersed in a room temperature curable epoxy resin, and then embedded and cured to create a block containing toner particles. A flaky sample is cut out from this block with a microtome equipped with diamond teeth, and used as a transmission electron microscope (TEM) imaging sample. A photograph of the cross-sectional shape of the toner particles is taken using this sample. In addition, you may dye | stain the whole block or a flaky sample using the dyeing liquid which used ruthenium tetroxide or a combination of ruthenium tetroxide and osmium tetroxide.

  The region of the resin phase B in the toner particles is visually confirmed from the photograph. Further, as a specific method of measuring the size of the independent phase, the equivalent circle equivalent diameter is obtained by calculating the image information taken by the image processing apparatus “Luzex F” (manufactured by Nireco), and this is used as the toner. The size is calculated as the size of the resin phase B included in the particles.

  In the toner according to the present invention, the resin constituting the resin phase B has a glass transition temperature of 50 ° C. or less, and the resin constituting the resin phase A has a glass transition temperature of 70 ° C. or less. It is preferable to use an amorphous vinyl-based copolymer in which the difference in glass transition temperature between the resin and the resin constituting the resin phase A is 20 ° C. or more. By combining resins having such properties, the problem of the present invention is achieved. It was confirmed that the problem was resolved.

  In the present invention, it is preferable to select the vinyl copolymer so that the glass transition temperature of the resin constituting the resin phase B encapsulated in the toner particles is 50 ° C. or lower, preferably 15 to 48 ° C. Further, it is preferable to select the vinyl copolymer so that the glass transition temperature of the resin constituting the resin phase A is 70 ° C. or lower, preferably 40 to 60 ° C.

  In the present invention, the glass transition temperature Tg is measured using an apparatus to be described later, and the base line extension below the glass transition temperature of the DSC thermogram in the glass transition region and the peak apex from the peak rising portion. The temperature with the tangent line indicating the maximum inclination is defined as the glass transition temperature.

  Specific examples of the means for measuring the glass transition temperature include a differential calorimeter (DSC), and examples thereof include an apparatus such as DSC-7 manufactured by PerkinElmer.

  As the temperature rise / cooling conditions, the measurement is allowed to stand at 0 ° C. for 1 minute, and then heated to 100 ° C. under the condition of 10 ° C./min (first temperature rise process). Next, after standing at 200 ° C. for 1 minute, it is cooled to 0 ° C. under the condition of 10 ° C./min (first cooling process). 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). Then, the endothermic peak temperature of the second heat (second temperature rise) was determined and used as the glass transition temperature Tg.

  Further, in the present invention, when designing the toner particles, it is necessary to calculate the theoretical glass transition temperature in order to grasp in advance the glass transition temperature of each vinyl polymer resin constituting the binder resin. Convenient to.

  Here, the theoretical glass transition temperature refers to the glass transition temperature when each component constituting the copolymer resin forms a homopolymer, by multiplying the respective composition mass fractions, that is, by weighted averaging, It is what I have sought.

  That is, the theoretical glass transition temperature Tg ′ (absolute temperature) is calculated from the following equation (1) when the glass transition temperature of the homopolymer of the component constituting the copolymer resin is used.

Formula (1)
1 / Tg ′ = W ₁ / T ₁ + W ₂ / T ₂ +... + W _n / T _n
(Wherein W ₁ , W ₂ ,... W _n are the mass fractions of each monomer with respect to the total monomers used in the production of the copolymer resin, T ₁ , T ₂ ... T _n. Indicates the glass transition temperature (absolute temperature) of the homopolymer formed using each monomer.)
In the toner according to the present invention, a slight deviation may occur between the theoretical glass transition temperature value calculated by calculation and the measurement result obtained by the differential calorimetric analyzer. Is not particularly problematic.

  Further, in the toner according to the present invention, the solubility parameter value (SP value) of the resin constituting the resin phase B and the solubility parameter value (SP value) of the resin constituting the resin phase A are different so as to have a difference. It has been confirmed that the problem of the present invention can be solved more reliably by designing a vinyl copolymer.

  As described above, the binder resin constituting the toner according to the present invention has a certain degree of difference in the solubility parameter value (SP value) of each of the plural types of vinyl copolymers used. The incompatibility between these resins is manifested.

By the way, the solubility parameter value (SP value) is a numerical value indicating the magnitude of the cohesive energy of a substance, and is an atom or atomic group according to the method “Polym. Eng. Sci., Vol14, p147 (1974)” proposed by Feors. Assuming that the evaporation energy and the molar volume are Δe _i and Δv _i , the solubility parameter value σ of the binder resin is calculated by the following equation (2).

Formula (2)
σ = (ΣΔe _i / ΣΔv _i ) ^1/2
The solubility parameter value of each vinyl copolymer is calculated from 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 parameters SPx and SPy of each monomer are calculated by the above formula (2), and specific values are described in documents such as the Polymer Handbook (published by Wiley) 4th edition. Use what you have.

  The solubility parameter value can be controlled by changing the composition ratio of 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 (http://polymer.nims.go.jp) provided in the database “PolyInfo” (http://polymer.nims.go.jp) provided by the National Institute for Materials Science //Polymer.nims.go.jp/guide/guide/p5110.html).

  Focusing on the molecular weight of the binder resin constituting the toner according to the present invention, the molecular weight is in the range of 15,000 to 25,000 and 25,000 to 35,000, more preferably 20,000 to 25,000 and 25. Each has a peak molecular weight in the range of 3,000 to 30,000. As described above, the binder resin constituting the toner according to the present invention is formed from a plurality of types of vinyl copolymers, but these resins do not have so much difference in molecular weight. . In the present invention, the plurality of types of resins constituting the binder resin have an incompatible relationship. However, the fact that the molecular weight does not have a large difference in this way is also a manifestation of incompatibility. This is considered to be an important factor.

  On the other hand, the present invention has found that the toner image can be stably fixed at a temperature similar to the boiling point of water, although the molecular weights of the plurality of types of resins do not have such a large difference.

  The peak molecular weight can be measured using gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a column solvent, and is calculated using the calibration curve described later from the count number of the obtained GPC chromatogram. Is done.

  Specifically, 1 ml of THF is added to 1 mg of a measurement sample, and the mixture is sufficiently dissolved by stirring using a magnetic stirrer at room temperature. Next, after filtration through a membrane filter having a pore size of 0.45 to 0.50 μm, the solution is injected into GPC. The measurement conditions of GPC are measured by stabilizing the column at 40 ° C., adding THF at a flow rate of 1 ml / min, and injecting about 100 μl of a sample having a concentration of 1 mg / ml. As the column, it is preferable to use a combination of commercially available polystyrene gel columns. For example, Shodex GPC KF-801, 802, 803, 804, 805, 806, 807 made by Showa Denko KK, TSKgel G1000H, G2000H, G3000H, G4000H, G5000H, G6000H, G7000H, TSK guard column manufactured by Tosoh Corporation Combinations can be given.

  As the detector, a refractive index detector (IR detector) or a UV detector is preferably used. In the measurement of the molecular weight of a sample, the molecular weight distribution of the sample is calculated using a calibration curve created using monodisperse polystyrene standard particles. About 10 points are preferably used as polystyrene for preparing a calibration curve.

  Further, paying attention to the molecular weight distribution of the binder resin constituting the toner according to the present invention, the binder resin used in the present invention has, for example, a molecular weight when the ratio of the resin constituting the resin phase B is 10% by mass. The ratio of the low molecular weight component of 5,000 or less is 20% by mass or less, preferably 10 to 19% by mass, which is achieved by the conventional technology as described above despite the small proportion of the low molecular weight component in the entire resin. It was found that a toner image at a low temperature that could not be formed can be stably formed. The molecular weight distribution can also be measured by the GPC described above.

  As described above, in the present invention, when the molecular weight distribution of the binder resin is measured, the ratio of the low molecular weight component of 5,000 or less is low, and the molecular weight of the resin constituting the resin phase B and the resin phase A is the above. It is an unexpected thing that the problem of the present invention was solved by using such a resin because the low-temperature fixing performance was expressed by using a material having no significant difference. Here, the ratio of the low molecular weight component may include not only the resin component but also the content of a release agent or the like in the toner.

  The toner according to the present invention may contain 250 to 20,000 ppm of a polyvalent metal element.

  The toner according to the present invention includes, for example, a toner particle described below in a toner particle for the reason of using a metal salt as an aggregating agent in a process of aggregating resin particles from a dispersion of resin particles prepared in an aqueous medium. Such a metal element is contained, and mainly a divalent or trivalent metal salt is contained.

  This is because, in the agglomeration step, a divalent or trivalent metal salt is preferably used because it has a smaller critical aggregation concentration (coagulation value or coagulation point) than a monovalent metal salt.

  In the present invention, since the toner particles contain a metal element, the toner particles have an effect of suppressing overcharging to the toner particles and imparting uniform chargeability, and also due to the electric action when the binder resin is aggregated. By imparting selectivity to the aggregation of the resin particles, it is presumed that it contributes to the formation of a structure having a resin phase encapsulated in the toner particles as shown in FIG.

  In particular, in order to stabilize and maintain the charging property with respect to the environment and to form a good structure as shown in FIG. 1, the toner according to the present invention uses the metal elements described above (in the form, metal, metal (Including ions and the like) is preferably contained in the toner in an amount of 250 to 20000 ppm, more preferably 800 to 5000 ppm.

  Next, the metal element contained in the toner according to the present invention will be described.

  Examples of monovalent metals include alkali metals such as sodium, potassium, and lithium. Examples of divalent metals include alkaline earth metals such as calcium and magnesium, manganese, copper, and examples of trivalent metals include iron, Aluminum etc. are mentioned. These metals are supplied as metal salts in the toner production process, and specific examples of metal salts are shown below.

  Specific examples of the monovalent metal salt include sodium chloride, potassium chloride, lithium chloride and the like. Examples of the metal salt of the divalent metal include magnesium chloride, calcium chloride, calcium nitrate, zinc chloride, copper sulfate, magnesium sulfate, manganese sulfate and the like. Examples of the trivalent metal salt include aluminum chloride and iron chloride. These are appropriately selected according to the purpose.

  The amount of metal in the toner is measured using an X-ray fluorescence analyzer “System 3270” (manufactured by Rigaku Denki Kogyo Co., Ltd.), and fluorescent X-rays emitted from metal species of metal salts (for example, calcium derived from calcium chloride) Measure strength. As a specific measuring method, a plurality of toners with known metal salt content ratios are prepared, each toner 5g is pelletized, the metal salt content ratio (mass ppm), and the fluorescence X from the metal species of the metal salt. The relationship (calibration curve) with the line intensity (peak intensity) is measured. Next, the toner (sample) whose metal salt content is to be measured is similarly pelletized, and the fluorescent X-ray intensity from the metal species of the metal salt is measured to determine the content, that is, the “metal content in the toner”. it can.

  Next, a toner manufacturing method according to the present invention will be described.

  The method for producing the toner according to the present invention is not particularly limited as long as the toner particles are formed through a process of forming resin particles of a plurality of types of vinyl copolymers and aggregating the resin particles. .

  Specific examples of the toner production method include an emulsion association method, a suspension polymerization method, a dispersion polymerization method, and a dissolution suspension method. Hereinafter, a method for producing a toner by an emulsion association method having an advantage of easily controlling the shape and size of the toner particles will be described.

  Examples of the method for producing a toner by the emulsion association method include a method for producing a toner by salting out / fusing resin particles disclosed in JP-A-2002-351142 in an aqueous medium.

  In this method, resin particles are dispersed in an aqueous medium using an emulsifier, and then a coagulant having a critical coagulation concentration or higher is added for salting out, and at the same time, heat melting at a temperature higher than the glass transition temperature of the formed polymer itself. Gradually grow the particle size while forming the fused particles, stop the particle growth by adding a large amount of water when the desired particle size is reached, and further smooth the particle surface while heating and stirring The toner is manufactured by controlling the shape.

  As another method for producing the toner according to the present invention, for example, there is a production method called an emulsion polymerization aggregation method described in JP-A No. 2001-305797, JP-A No. 2002-214838, and the like. In this method, a resin particle dispersion prepared by emulsion polymerization is mixed and dispersed with a colorant dispersion and a release agent dispersion obtained by dispersing in fine particles, and the toner particles are aggregated by heating. To manufacture.

  In any of these toner production methods, toner particles are produced through a process of agglomerating resin particles produced by an emulsion polymerization method in an aqueous medium.

  An aqueous medium here means the medium which consists of 50-100 mass% of water and 0-50 mass% of water-soluble organic solvents. Examples of the water-soluble organic solvent include methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, tetrahydrofuran, and the like, and an alcohol-based organic solvent that does not dissolve the obtained resin is preferable.

  The ratio (mass ratio) between the polymerizable monomer and the aqueous medium during polymerization is preferably in the range of 1/10 to 1/2.

  As shown in FIG. 1, the toner according to the present invention has a structure comprising a resin phase A and a resin phase B included in the resin phase A. In the present invention, a plurality of incompatible vinyl copolymers constituting the binder resin are used, and a resin formed using a monomer having two or more polar groups in at least one of these resins. The toner particles having a structure as shown in FIG. 1 can be obtained by selecting a toner.

  That is, in the present invention, in the step of aggregating resin particles, even if a plurality of types of resin particles coexist, each resin particle does not agglomerate randomly, but at least two or more polar groups described above are present. After the resin particles formed by using the monomer having the particles are preferentially aggregated, the remaining resin particles are aggregated to form toner particles. In addition, there is a tendency that the colorant and the release agent component are not contained in the resin phase B made of a resin formed of a monomer having two or more polar groups. This is because the resin particles are agglomerated in the resin phase B even in the production methods disclosed in JP-A-2001-305797 and JP-A-2002-214838 described above, in which the resin particles are aggregated in the coexistence of the colorant and the release agent. It was confirmed that no agent was contained.

  The toner particle dispersion prepared through the resin particle aggregation process in such an aqueous medium is washed, dehydrated, and dried through the following solid-liquid separation / washing process and drying process.

  That is, in the solid-liquid separation / washing step, a toner cake is obtained by solid-liquid separation of the toner particles from the dispersion of toner particles obtained in the above step, and a surfactant or salting-out agent is obtained from the obtained toner cake. And a cleaning process for removing deposits and the like. The solid-liquid separation / washing method is not particularly limited, and examples thereof include a centrifugal separation method, a vacuum filtration method using Nutsche and the like, a filtration method using a filter press and the like.

  In the drying process, the washed toner particles are dried. Dryers used in the drying process include spray dryers, vacuum freeze dryers, vacuum dryers, stationary shelf dryers, mobile shelf dryers, fluidized bed dryers, rotary dryers, stirring dryers, etc. However, it is not particularly limited.

  The water content in the dried toner particles is preferably 5% by mass or less, and more preferably 2% by mass or less.

  Next, elements such as a release agent, a colorant, and a surfactant used for toner production will be described. The polymerizable monomer is as described above, and a description thereof is omitted here.

  It does not specifically limit as a mold release agent, A well-known thing can be used. Specific examples include low molecular weight polypropylene (number average molecular weight = 1500 to 9000), low molecular weight polyolefin waxes such as low molecular weight polyethylene, paraffin wax, Fischer-Tropsch wax, and ester wax. An ester wax represented by the following general formula can be preferably used.

General formula
R _1- (OCO-R ₂ ) n
In formula, n represents the integer of 1-4, Preferably it is 1-4, More preferably, it is 1-2.

R ₁ and R ₂ represent a hydrocarbon group which may have a substituent.

R ₁ : carbon number = 1-40, preferably 1-30, more preferably 16-26
R ₂ : carbon number = 1-40, preferably 14-30, more preferably 16-26
Specific examples of the ester compound represented by the above general formula are shown below, among which behenyl behenate, stearyl stearate, behenyl stearate, stearyl behenate and the like are preferable. In addition, paraffin wax modified with a polar group, higher alcohol, and the like are preferably used.

  The content of the release agent in the toner particles is preferably 1 to 30% by mass, more preferably 7 to 27% by mass, and still more preferably 10 to 25% by mass of the total amount of toner particles.

  Conventionally known organic pigments and dyes can be used as the colorant, and specific organic pigments and dyes are exemplified below.

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

  Examples of the pigment for orange or yellow include C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 185, C.I. I. Pigment yellow 155, C.I. I. And CI Pigment Yellow 156.

  Examples of the pigment for green or cyan include C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 16, C.I. I. Pigment blue 60, C.I. I. And CI Pigment Green 7.

  Examples of the dye include C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 122, C.I. I. Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162, C.I. I. Solvent Blue 25, 36, 60, 70, 93, 95, etc. can be used, and mixtures thereof can also be used.

  These organic pigments and dyes can be used alone or in combination as required.

  The content ratio of the colorant in the toner particles is preferably 2 to 20% by mass, more preferably 3 to 15% by mass, based on the total amount of toner particles.

  In the toner production process according to the present invention, it is preferable to disperse oil droplets in an aqueous medium using a surfactant. The surfactant that can be used in this case is not particularly limited, and the following ionic surfactants can be given as examples of suitable compounds.

  Examples of the ionic surfactant include sulfonate (sodium dodecylbenzenesulfonate, sodium arylalkylpolyethersulfonate, 3,3-disulfonediphenylurea-4,4-diazo-bis-amino-8-naphthol- 6-sulfonate sodium, ortho-carboxybenzene-azo-dimethylaniline, 2,2,5,5-tetramethyl-triphenylmethane-4,4-diazo-bis-β-naphthol-6-sulfonate sodium, etc.) , Sulfate 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, stearyl Potassium, calcium oleate and the like).

  Moreover, it is preferable to use together the surfactant of the following general formula (1), (2).

General formula (1)
R ₁ (OR ₂ ) _n OSO ₃ M
General formula (2)
R ₁ (OR ₂ ) _n SO ₃ M
In the general formulas (1) and (2), R ₁ represents an alkyl group or arylalkyl group having 6 to 22 carbon atoms, preferably an alkyl group or arylalkyl group having 8 to 20 carbon atoms, more preferably It is a C9-16 alkyl group or arylalkyl group.

In the general formulas (1) and (2), R ₂ represents an alkylene group having 2 to 6 carbon atoms, preferably an alkylene group having 2 to 3 carbon atoms. Examples of the alkylene group having 2 to 6 carbon atoms represented by R ₂ include an ethylene group, a trimethylene group, a tetramethylene group, a propylene group, and an ethylethylene group.

  In general formula (1), (2), n is an integer of 1-11, Preferably it is 2-10, More preferably, it is 2-5, Most preferably, it is 2-3.

  In the general formulas (1) and (2), examples of the monovalent metal element represented by M include sodium and lithium. Of these, sodium is preferably used.

  Specific examples of the surfactant represented by the general formulas (1) and (2) are shown below, but the present invention is not limited thereto.

Compound _{(101): C 10 H 21} (OCH 2 CH 2) 2 OSO 3 Na
Compound _{(102): C 10 H 21} (OCH 2 CH 2) 3 OSO 3 Na
Compound _{(103): C 10 H 21} (OCH 2 CH 2) 2 SO 3 Na
Compound _{(104): C 10 H 21} (OCH 2 CH 2) 3 SO 3 Na
Compound (105): C ₈ H ₁₇ (OCH ₂ CH (CH ₃ )) ₂ OSO ₃ Na
Compound (106): C ₁₈ H ₃₇ (OCH ₂ CH ₂ ) ₂ OSO ₃ Na
In the toner manufacturing process according to the present invention, there is a step of aggregating resin particles from a dispersion of resin particles prepared in an aqueous medium using an aggregating agent, and a metal salt is preferably used as the aggregating agent. As a specific coagulant, a divalent or trivalent metal salt is preferably used as the coagulant, and the divalent or trivalent metal salt is more critical than the monovalent metal salt. A coagulation point is small, which is preferable.

  The critical flocculation concentration referred to in the present invention is an index relating to the stability of the dispersion in the aqueous dispersion, and indicates the addition concentration of the flocculating agent when the flocculating agent is added and aggregation occurs. This critical coagulation concentration varies greatly depending on the latex itself and the dispersant. For example, it is described in Seizo Okamura et al., Polymer Chemistry 17,601 (1960), etc., and the value can be known by following these descriptions.

  As another method, a desired salt is added to the target particle dispersion at different concentrations, the ζ potential of the dispersion is measured, and the salt concentration at the point where the ζ potential starts to change is defined as the critical aggregation concentration. It is also possible to do.

  The polymerization initiator is not particularly limited as long as it is a commonly used oil-soluble polymerization catalyst that is soluble in the polymerizable monomer. For example, benzoyl peroxide, lauroyl peroxide, t-butylperoxyoctate can be used. Peroxide catalysts such as ate, and azo catalysts such as azobisisobutyronitrile and azobisisovaleronitrile can be used.

  After these polymerization initiators are dissolved in the polymerizable monomer and added to an aqueous medium containing inorganic particles and an amphoteric surfactant or a dispersion stabilizing aid added as necessary, the primary suspension is Produced.

  As the inorganic particles functioning as a dispersion stabilizer, colloidal silica having a volume average primary particle diameter of 6 to 32 nm, preferably 7 to 17 nm, aluminum oxide, acid value zirconium, zinc antimonate, titanium oxide, And mixtures thereof are preferably used.

  The average value of the circularity of the toner of the present invention is preferably 0.951 to 0.988.

  In order to control the shape of the toner within the above range, an appropriate process end time may be determined while monitoring the characteristics of the toner particles whose shape is being controlled in a process such as association or fusion.

  Monitoring means that a measuring device is incorporated in-line, and process conditions are controlled based on the measurement result. In other words, in the case of a polymerization method toner that is formed by incorporating measurement such as shape in-line, for example, by associating or fusing resin particles in an aqueous medium, the shape or particle size is measured while performing sequential sampling in the fusing step. The reaction is stopped when the desired shape is obtained.

  Although it does not specifically limit as a monitoring method, The flow type particle image analyzer "FPIA-2000" (made by Toa Medical Electronics Co., Ltd.) can be used. This apparatus is suitable because the shape can be monitored by performing image processing in real time while passing the sample liquid. That is, a pump or the like is used from the reaction field, and the shape is measured continuously, and the reaction is stopped when the desired shape is obtained.

  The toner preferably has a volume-based median diameter (volume D50% diameter) of 2 to 7 μm, more preferably 2.5 to 6.5 μm. When toner particles are formed by a polymerization method, it can be controlled by the concentration of the aggregating agent, the amount of the organic solvent added, the fusing time, and the composition of the polymer itself.

  Since the volume-based median diameter (volume D50% diameter) is 2 to 7 μm, toner particles having high adhesion force that fly and adhere to the heating member to generate offset in the fixing process are reduced, and transfer efficiency is improved. The image quality of halftone is improved and the image quality of fine lines and dots is improved.

  The volume-based median diameter (volume D50% diameter) of toner is measured and calculated using a device in which a computer system for data processing (Beckman Coulter) is connected to Coulter Multisizer III (Beckman Coulter, Inc.). can do.

  As a measurement procedure, 0.02 g of toner is blended with 20 ml of a surfactant solution (for example, a surfactant solution obtained by diluting a neutral detergent containing a surfactant component 10 times with pure water for the purpose of dispersing the toner). After that, ultrasonic dispersion is performed for 1 minute to prepare a toner dispersion. This toner dispersion is injected into a beaker containing ISOTON II (manufactured by Beckman Coulter, Inc.) in a sample stand with a pipette until a measurement concentration of 5 to 10% is reached, and the measuring machine count is set to 2500. To do. The aperture diameter of the Coulter Multisizer was 50 μm.

  In the toner of the present invention, the toner particles prepared as described above may be used as they are, but it is preferable to use so-called external additives for the purpose of improving fluidity and cleaning properties. . These external additives are not particularly limited, and various inorganic fine particles, organic fine particles and lubricants can be used.

  Examples of inorganic fine particles that can be used as an external additive include conventionally known fine particles. Specifically, silica fine particles, titanium oxide fine particles, alumina fine particles and the like can be preferably used. These inorganic fine particles are preferably hydrophobic.

  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 Co., Ltd. -200, commercially available products TS-720, TS-530, TS-610, H-5, MS-5, spherical monodispersed silica manufactured by Cabot Corporation.

  Specific examples of the titanium oxide fine particles include, for example, commercial products T-805 and T-604 manufactured by Nippon Aerosil Co., Ltd., and commercial products MT-100S, MT-100B, MT-500BS, MT-600 manufactured by Teika Co., Ltd. MT-600SS, JA-1 etc. are mentioned.

  Specific examples of the titanium oxide fine particles include commercial products TA-300SI, TA-500, TAF-130, TAF-510, TAF-510T manufactured by Fuji Titanium Co., Ltd., and commercial products IT-S, IT manufactured by Idemitsu Kosan Co., Ltd. -OA, IT-OB, IT-OC, rutile type titanium oxide and the like.

  Specific 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.

  Examples of the organic fine particles that can be used as the external additive include spherical fine particles having a number average primary particle diameter of about 10 to 2000 nm. Examples of the constituent material of the organic fine particles include polystyrene, polymethyl methacrylate, styrene-methyl methacrylate copolymer and the like.

  Examples of the lubricant that can be used as an external additive include metal salts of higher fatty acids. Specific examples of the metal salts of such higher fatty acids include zinc stearate, aluminum stearate, copper stearate, magnesium stearate, calcium stearate, and the like; zinc oleate, manganese oleate, iron oleate, olein Oleic acid metal salts such as acid copper and magnesium oleate; palmitate metal salts such as zinc palmitate, copper palmitate, magnesium palmitate and calcium palmitate; linoleic acid metal salts such as zinc linoleate and calcium linoleate; ricinol Examples include ricinoleic acid metal salts such as zinc acid and calcium ricinoleate.

  The addition amount of the external additive is preferably about 0.1 to 5% by mass with respect to the toner particles.

  Examples of the apparatus for adding and mixing the external additive to the toner particles include various known mixing apparatuses such as a Turbuler mixer, a Henschel mixer, a Nauter mixer, and a V-type mixer.

  The toner of the present invention can be used for a one-component developer or a two-component developer. When used as a one-component developer, a non-magnetic one-component developer or a magnetic one-component developer containing about 0.1 to 0.5 μm of magnetic particles in the toner can be used.

  However, it is more preferable that the toner of the present invention is mixed with magnetic particles and used for a two-component developer. As the carrier used as the magnetic particles, conventionally known materials such as metals such as iron, ferrite and magnetite, and alloys of these metals with metals such as aluminum and lead can be used. Among these, ferrite particles are preferable. The magnetic particles preferably have a volume average particle size of 15 to 100 μm, more preferably 25 to 80 μm.

  The volume average particle diameter of the carrier can be typically measured by a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by SYMPATEC) equipped with a wet disperser.

  The carrier is preferably a 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, silicone resin, ester resin, or fluorine-containing polymer resin is used. In addition, the resin for constituting the resin-dispersed carrier is not particularly limited, and a known resin can be used. For example, a styrene-acrylic resin, a polyester resin, a fluorine resin, a phenol resin, or the like is used. be able to.

  Next, an image forming apparatus used in the image forming method using the toner of the present invention will be described.

  FIG. 2 is a cross-sectional configuration diagram illustrating an example of an image forming apparatus in which the toner according to the present invention is preferably used.

  In FIG. 2, reference numeral 4 denotes a photosensitive drum as a member to be charged, which is formed by forming an organic photoconductor (OPC) as a photosensitive layer on the outer peripheral surface of an aluminum drum base. Rotates at speed.

  In FIG. 2, exposure light is emitted from the semiconductor laser light source 1 based on information read by a document reading device (not shown). This is distributed in the direction perpendicular to the paper surface of FIG. 1 by the polygon mirror 2 and irradiated onto the surface of the photoreceptor through an fθ lens 3 that corrects image distortion, thereby forming an electrostatic latent image. The photosensitive drum 4 is uniformly charged in advance by the charger 5 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 6, and the formed developed image is transferred to the transfer paper (recording paper) 8 that has been conveyed in time by the action of the transfer device 7. . Further, the photosensitive drum 4 and the transfer paper 8 are separated by a separator (separation pole) 9, but the developed image is transferred and supported on the transfer paper 8 and led to the fixing device 10 to be fixed.

  Untransferred toner or the like remaining on the surface of the photoreceptor is cleaned by a cleaning device 11 of a cleaning blade type, removed residual charge by pre-charge exposure (PCL) 12, and again by the charger 5 for the next image formation. Uniformly charged.

  Next, the recording paper is typically plain paper, but is not particularly limited as long as it can transfer an unfixed image after development, and of course includes an OHP PET base.

  The cleaning blade 13 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.

  The present invention can be preferably used for an electrophotographic image forming apparatus, particularly an apparatus for forming an electrostatic latent image on a photosensitive member by a modulated beam modulated with digital image data from a computer or the like.

  In recent years, in the field of electrophotography where an electrostatic latent image is formed on a photosensitive member and the latent image is developed to obtain a visible image, image quality can be improved, converted, edited, etc., and high-quality image formation is possible. Research and development of image forming methods adopting various digital methods have been actively conducted.

  As a scanning optical system that optically modulates with a digital image signal from a computer or a copy original employed in the image forming method and apparatus, an optical optical modulator is interposed in the laser optical system, and the optical modulation is performed by the acoustooptic modulator. There is an apparatus that directly modulates the laser intensity using a semiconductor laser, and forms a dot image by spot exposure on a uniformly charged photoconductor from these scanning optical systems.

  The beam irradiated from the scanning optical system described above has a circular or elliptical luminance distribution that approximates a normal distribution with a skirt extending from side to side. For example, in the case of a laser beam, the main scanning direction or One or both in the sub-scanning direction is an extremely narrow circle or ellipse of 20 to 100 μm.

  The toner of the present invention is suitably used in an image forming method including a step of fixing an image support on which a toner image is formed between a heating roller and a pressure roller constituting a fixing device.

  FIG. 3 is a cross-sectional view showing an example of a fixing device used for image formation using the toner according to 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, T is a toner image formed on transfer paper (recording paper).

  The heating roller 71 is formed by forming a coating layer 82 made of a fluororesin or an elastic body on the surface of a 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 silicone rubber and silicone sponge rubber having good heat resistance such as LTV, RTV, and HTV.

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

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

  When the Asker C hardness of the elastic body constituting the covering layer 82 exceeds 80 ° and when the thickness of the covering layer 82 is less than 0.1 mm, the fixing nip cannot be increased, and soft fixing is performed. (For example, the effect of improving the color reproducibility by the toner layer at the smoothed interface) cannot be exhibited.

  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 covering layer 84 is not particularly limited, and examples thereof include various soft rubbers such as urethane rubber and silicone rubber, and sponge rubber, and the silicone rubber exemplified as constituting the covering layer 84 and It is preferable to use silicone sponge rubber.

  The Asker C hardness of the elastic body constituting the coating layer 84 is less than 80 °, preferably less than 70 °, and more preferably less than 60 °.

  The thickness of the coating layer 84 is 0.1 to 30 mm, preferably 0.1 to 20 mm.

  When the Asker C hardness of the elastic body constituting the coating layer 84 exceeds 80 ° and when the thickness of the coating layer 84 is less than 0.1 mm, the fixing nip cannot be increased, and soft fixing is not performed. The effect cannot be demonstrated.

  Although it does not specifically limit as a material which comprises the metal core 83, Metals, such as aluminum, iron, copper, or those alloys can be mentioned.

  The contact load (total load) between the heating roller 10 and the pressure roller 72 is usually 40 to 350 N, preferably 50 to 300 N, and more preferably 50 to 250 N. This contact load is defined in consideration of the strength of the heating roller 10 (thickness of the cored bar 81). For example, a heating roller having a cored bar made of iron of 0.3 mm should be 250 N or less. Is preferred.

Further, from the viewpoint of offset resistance and fixing property, it is preferable that as the nip width is 4 to 10 mm, the surface pressure of the nip to be ^{0.6 × 10 5 Pa~1.5 × 10 5} Pa preferable.

  An example of fixing conditions by the fixing device shown in FIG. 3 is that the fixing temperature (surface temperature of the heating roller 10) is 70 to 210 ° C., and the fixing linear velocity is 80 to 640 mm / sec.

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

<Production of toner>
<Preparation of Toner 1>
(Preparation of resin particle (A1) dispersion)
An activator solution in which 7.08 g of an anionic activator (sodium dodecylbenzenesulfonate: SDS) is dissolved in 2760 g of ion-exchanged water in advance is put into a separable flask equipped with a stirrer, a temperature sensor, a condenser, and a nitrogen introducing device. Then, the internal temperature was raised to 80 ° C. while stirring at a stirring speed of 230 rpm under a nitrogen stream.

On the other hand, Exemplified Compound (20) 72.0 g
Styrene 115.1g
n-Butyl acrylate 42.0g
Methacrylic acid 10.9g
Were heated and dissolved at 80 ° C. to prepare a monomer solution. Here, the two heated solutions were mixed and dispersed by a mechanical disperser having a circulation path to produce emulsified particles having a uniform dispersed particle size.

  Next, a resin particle was produced by adding a solution obtained by dissolving 0.84 g of a polymerization initiator (potassium persulfate: KPS) in 200 g of ion-exchanged water, and heating and stirring at 80 ° C. for 3 hours. Subsequently, 8.00 g of a polymerization initiator (KPS) and a solution obtained by dissolving 10.0 g of 2-chloroethanol as a water-soluble chain transfer agent in 240 g of ion-exchanged water were added, and after 15 minutes, styrene 383 at 80 ° C. .6 g, a mixed solution of 140.0 g of n-butyl acrylate and 36.4 g of methacrylic acid (second monomer solution) was dropped over 120 minutes. After completion of dropping, the mixture was heated and stirred for 60 minutes and then cooled to 40 ° C. to obtain a dispersion of resin particles.

  This resin particle dispersion is referred to as “resin particle (A1) dispersion”.

(Preparation of resin particle (A2) dispersion)
The amount of styrene added in the above-mentioned “resin particle (A1) dispersion” is reduced by 10% by mass (the initial addition amount is 103.5 g, the subsequent addition amount is 345.2 g), and the addition amount of n-butyl acrylate is reduced. Increase by 10% by mass (initial addition amount: 46.2g, later addition amount: 154.0g), decrease in addition amount of methacrylic acid by 10% by mass (initial addition amount: 9.8g, later addition amount) A “resin particle (A2) dispersion” was obtained in the same manner except for 32.8 g).

(Preparation of resin particle (A3) dispersion)
The amount of styrene added in the above-mentioned “resin particle (A1) dispersion” is increased by 10% by mass (the initial addition amount is 126.6 g, the subsequent addition amount is 422.0 g), and the addition amount of n-butyl acrylate is increased. Decrease by 10% by mass (initial addition amount is 37.8g, later addition amount is 126.0g), increase methacrylic acid addition amount by 10% by mass (initial addition amount is 12.0g, later addition amount is 40.0 g) was used in the same manner to obtain “resin particle (A3) dispersion”.

(Preparation of resin particle (A4) dispersion)
A “resin particle (A4) dispersion” was obtained in the same manner except that the exemplified compound (20) used in the preparation of the “resin particle (A1) dispersion” was not added.

  Table 1 shows the types and ratios of the polymerizable monomers used to form the “resin particles (A1) to (A4) dispersions”, the release agent used, and the molecular weight.

(Preparation of resin particle (B1) dispersion)
An activator solution in which 7.08 g of an anionic activator (sodium dodecylbenzenesulfonate: SDS) is dissolved in 2760 g of ion-exchanged water is added to a separable flask equipped with a stirrer, temperature sensor, condenser, and nitrogen introduction device. To do. The internal temperature was raised to 80 ° C. while stirring at a stirring speed of 230 rpm under a nitrogen stream.

On the other hand, 125.0 g of styrene
2-ethylhexyl acrylate 75.0g
Maleic acid 50.0g
Were mixed and heated to 80 ° C. for dissolution to prepare a monomer solution. Here, the two heated solutions were mixed and dispersed by a mechanical disperser having a circulation path to produce emulsified particles having a uniform dispersed particle size. Next, a dispersion solution of resin particles was obtained by adding a solution obtained by dissolving 0.84 g of a polymerization initiator (potassium persulfate: KPS) in 200 g of ion-exchanged water, and heating and stirring at 80 ° C. for 3 hours. This resin particle dispersion is referred to as “resin particle (B1) dispersion”.

(Preparation of resin particle (B2) dispersion)
The amount of styrene used in the preparation of the “resin particle (B1) dispersion” described above was changed from 125.0 g to 87.5 g, the amount of 2-ethylhexyl acrylate was changed from 75.0 g to 125.0 g, and maleic acid. A “resin particle (B2) dispersion” was obtained in the same manner except that the amount of was changed from 50.0 g to 37.5 g.

(Preparation of resin particle (B3) dispersion)
A “resin particle (B3) dispersion” was obtained in the same manner except that the maleic acid used in the preparation of the “resin particle (B1) dispersion” was changed to itaconic acid.

(Preparation of resin particle (B4) dispersion)
In place of 87.5 g of styrene and 75.0 g of 2-ethylhexyl acrylate used in the preparation of the above-mentioned “resin particle (B1) dispersion”, 125.0 g of 2-ethylhexyl methacrylate and 50.0 g of maleic acid were used. Instead, a “resin particle (B4) dispersion” was obtained in the same manner except that it was changed to 37.5 g of itaconic acid.

(Preparation of resin particle (B5) dispersion)
“Resin Particle (B5) Dispersion” was similarly performed except that the amount of styrene used in the preparation of “Resin Particle (B1) Dispersion” described above was changed to 162.5 g and 50.0 g of maleic acid to 12.5 g of itaconic acid. Liquid "was obtained.

(Preparation of resin particle (B6) dispersion)
In the same manner as in the above-mentioned “resin particle (B1) dispersion”, except that 75.0 g of 2-ethylhexyl acrylate was used instead of 75.0 g of 2-ethylhexyl acrylate, “resin particles ( B6) Dispersion "was obtained.

(Preparation of resin particle (B7) dispersion)
The amount of styrene used in the preparation of the above-mentioned “resin particle (B1) dispersion” was 162.5 g, acrylic acid-2-ethylhexyl 75.0 g, methacrylate-2-ethylhexyl 62.5 g, and maleic acid 50.0 g. A “resin particle (B7) dispersion” was obtained in the same manner except that it was changed to 25.0 g of itaconic acid.

(Preparation of resin particle (B8) dispersion)
The amount of styrene used in the preparation of the aforementioned “resin particle (B1) dispersion” was 50.0 g, 75.0 g of 2-ethylhexyl acrylate was 112.5 g of 2-ethylhexyl methacrylate, and 50.0 g of maleic acid was 50.0 g. A “resin particle (B8) dispersion” was obtained in the same manner except that it was changed to 87.5 g of itaconic acid.

(Preparation of resin particle (B9) dispersion)
Styrene and maleic acid used in the preparation of the above-mentioned “resin particle (B1) dispersion” were not used, and 250.0 g of 2-ethylhexyl acrylate was used to obtain “resin particle (B9) dispersion”.

(Preparation of resin particle (B10) dispersion)
A “resin particle (B10) dispersion liquid” was obtained using 250.0 g of styrene without using the 2-ethylhexyl acrylate and maleic acid used in the preparation of the “resin particle (B1) dispersion liquid”.

  Table 2 shows the types and ratios and molecular weights of the polymerizable monomers used to form the “resin particles (B1) to (B10) dispersions”.

(Preparation of colorant dispersion 1)
9.2 g of sodium n-dodecyl sulfate is dissolved with stirring in 160 g of ion-exchanged water. Under stirring, 20 g of carbon black “Regal 330R” (manufactured by Cabot) was gradually added, and then dispersed using CLEARMIX to obtain a dispersion. As a result of measuring the particle diameter of the colorant in the dispersion using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.), the mass average diameter was 112 nm. This dispersion is referred to as “colorant dispersion 1”.

(Preparation of mold release agent dispersion 1)
An activator solution in which 7.08 g of an anionic activator (sodium dodecylbenzenesulfonate: SDS) is dissolved in 276 g of ion-exchanged water is put into a separable flask equipped with a stirrer, a temperature sensor, a condenser, and a nitrogen introduction device. Then, while stirring at a stirring speed of 230 rpm under a nitrogen stream, 7.2 g of the exemplified compound (20) was added and mixed and dispersed to obtain a dispersion. As a result of measuring the particle diameter of the release agent in the dispersion using an electrophoretic light scattering photometer “ELS-800” (manufactured by Otsuka Electronics Co., Ltd.), the mass average diameter was 100 nm. This dispersion is referred to as “release agent dispersion 1”.

(Preparation of toner particles 1)
1250 g of the aforementioned “resin particle dispersion (A1)”, 125 g of “resin particle dispersion (B1)”, 2000 g of ion-exchanged water and “colorant dispersion 1” were added to a temperature sensor, a cooling tube, a nitrogen introducing device, and a stirring device. In a 5 liter four-necked flask with After adjusting to 30 degreeC, 5 mol / L sodium hydroxide aqueous solution was added to this solution, and pH was adjusted to 10.0. Subsequently, an aqueous solution in which 52.6 g of magnesium chloride hexahydrate was dissolved in 72 g of ion-exchanged water was added at 30 ° C. for 10 minutes with stirring. Thereafter, after standing for 3 minutes, temperature increase was started, and the temperature was increased to 90 ° C. in 6 minutes (temperature increase rate = 10 ° C./min). In this state, the particle size was measured with “Coulter Counter TA-III” (manufactured by Coulter Beckman). The particle growth was stopped by adding, and the mixture was further heated and stirred for 6 hours at a liquid temperature of 90 ° C. ± 2 ° C. for fusion. Then, it cooled to 30 degreeC on the conditions of 6 degreeC / min, hydrochloric acid was added, pH was adjusted to 2.0, and stirring was stopped.

  The produced toner particles were subjected to solid-liquid separation, and washing with ion exchange water was repeated four times (the amount of ion exchange water was 15 liters), and then dried with hot air at 40 ° C. to obtain toner particles. This is referred to as “toner particle 1”.

(Production of toner particles 2 to 11 and 13 to 17)
The “resin particle (A1) dispersion” and “resin particle (B1) dispersion” used in the preparation of “toner particle 1” were changed as shown in Table 3, and “toner particles 2-11, 13˜ 17 "was obtained.

(Preparation of toner particles 12)
1000 g of the above-mentioned “resin particle (A4) dispersion”, 120 g of “resin particle (B4) dispersion”, 2000 g of ion-exchanged water, 100 g of “colorant dispersion 1”, and 100 g of “release agent dispersion 1” “Toner particle 12” was prepared in the same four-necked flask as that used for preparation of “toner particle 1”, and “toner particle 12” was prepared in the same manner as “toner particle 1”.

  As described above, the “toner particles 12” are toner particles produced by coagulating a colorant and a release agent in the presence of resin particles.

  Table 3 shows the ratio of the resin particles (A) forming the resin phase A and the resin particles (B) forming the resin phase B used for the production of the “toner particles 1 to 17”, the peak molecular weight, and the molecular weight of 5,000 or less. , The size of the resin phase B, the glass transition temperature, and the SP value.

  Here, the ratio between the peak molecular weight and the resin having a molecular weight of 5,000 or less was obtained by the gel permeation chromatography (GPC) described above, and the glass transition temperature was obtained by a differential thermal analyzer (DSC). The parameter value is calculated from the above equation (3).

  Furthermore, the confirmation of the resin phase B is based on the observation result by the transmission electron microscope apparatus (TEM) “S-5000H type” (manufactured by Hitachi, Ltd.).

  As shown in Table 3, it was confirmed that the “toner particles 1 to 12 and 15” according to the present invention have a structure in which the resin phase B is included in the toner particles. 14, 16, 17 ", the resin phase B could not be confirmed in the toner particles.

  The dried “toner particles 1 to 17” were measured for the amount of metal element remaining on the surface of the toner particles with the above-described fluorescent X-ray analyzer “system 3270 type” (manufactured by Rigaku Denki Kogyo Co., Ltd.). It was confirmed to be ˜5,000 ppm.

<Toner particle external additive treatment>
Subsequently, 1% by mass of hydrophobic silica (number average primary particle size = 12 nm, degree of hydrophobicity = 68) and hydrophobic titanium oxide (number average primary particle size) were prepared in each of the “toner particles 1 to 17” produced above. = 20 nm, hydrophobization degree = 63) was added in an amount of 1% by mass, and the mixture was mixed using a “Henschel mixer” (manufactured by Mitsui Miike Chemical Co., Ltd.). Thereafter, coarse particles were removed using a sieve having an opening of 45 μm to prepare “Toners 1 to 17”.

<< Preparation of developer >>
To each of the “toners 1 to 17” produced above, a ferrite carrier having a volume average particle diameter of 60 μm coated with a silicone resin is mixed so that the toner concentration becomes 6% by mass, and “developers 1 to 17” are mixed. Prepared.

<Evaluation>
The following items were evaluated for “Developers 1 to 17” produced above. Incidentally, those using “Developers 1 to 12, 15 (Toners 1 to 12, 15)” are referred to as “Examples 1 to 13”, “Developers 13, 14, 16, 17 (Toners 13, 14, 16, 17) "was designated as" Comparative Examples 1-4 ".

  As an evaluation machine, a commercially available multifunction machine “Sitios 7165” (manufactured by Konica Minolta Business Technologies, Inc.) employing an electrophotographic method was used.

<Toner storage stability (heat-resistant storage stability)>
100 g of each toner was allowed to stand at 55 ° C. and 90% RH for 24 hours, and then sieved with a sieve having an opening of 45 μm. The toner storage stability was evaluated by the amount (ratio) of aggregates remaining on the sieve.

Evaluation Criteria ◎: Less than 5% on the sieve, very little aggregation and excellent (no generation of aggregates even if transported in summer without any insulation packaging)
○: The amount on the sieve is less than 5 to 30% and the amount of agglomeration is small and good (no aggregation occurs even if transported in the summer with cardboard packaging only)
X: The amount on the sieve is 30% or more, and the agglomeration amount is large, which is a practical problem (need to be transported by cooling).

<Evaluation of fixability>
The surface temperature of the heating roller of the fixing device of the evaluator was changed so that the paper temperature 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 printed image, A4 size plain paper (basis weight 64 g / m ² ) 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 producing a 2.54 cm square solid black print image with a toner adhesion amount of 0.6 mg / cm ² , the image density before and after peeling with “Scotch Mending Tape” (manufactured by Sumitomo 3M). And the residual ratio of the image density was determined as the fixing ratio.

  A fixing temperature at which a fixing rate of 95% or more is obtained is defined as a fixing possible temperature. For the measurement of the image density, a reflection densitometer “RD-918” (manufactured by Macbeth) was used.

Evaluation criteria A: Fixing is possible at a paper temperature of 90.degree. C. or less. O: Fixing is possible at a paper temperature of 120.degree. C. or less.

<Fixability of extra thick paper>
Continuous printing was performed using 500 sheets of extremely thick postcards (thickness 0.4 mm) manufactured by Heart Co., Ltd. and using the image forming apparatus shown in FIG. 2 as an evaluation machine. The ranks of the obtained prints were evaluated as follows.

Evaluation Criteria A: Toner does not peel off even if the character is strongly written with a pen on the 500th print image ○: The toner is peeled off when the character is strongly written with a pen on the 500th print image, but a ballpoint pen When the character is strongly written, the toner does not peel off. X: The toner is peeled off and the hand becomes dirty just by touching the 500th printed image.

<Fixability of coated paper>
Print on 250 sheets of coated paper (60 g / m ² ) manufactured by Daio Paper Co., Ltd., turn 10 times with the thumb of one hand, and observe smudged stains around the characters visually and with a magnifying glass (magnification 10 times). The rank was evaluated.

Evaluation criteria ◎: No smudges are generated at all ○ ○: No smudges are observed with the naked eye, but there is no problem in practical use only by detecting the stains with a magnifying glass ×: The mark on the thumb is black Dirty as if smeared.

<Offset resistance>
A high quality paper (200 g / m ² ) thick paper is used as the recording paper, and a line image with a width of 0.3 mm and a length of 150 mm is formed parallel to the paper traveling direction (heat roller circumferential direction) and visually offset. The white paper and the toner on the surface of the heating roller were evaluated.

Evaluation Criteria A: Blank paper stain due to offset and toner stain on heating roller surface are not seen at all. Excellent: Blank paper stain due to offset cannot be confirmed, but there is toner stain on the heating roller surface. X: Blank paper stain due to offset. Confirmed and practically problematic.

<Glossiness>
Art paper (manufactured by Mitsubishi Paper Industries Co., Ltd., Tokuhishi Art) was used as the recording paper, and the printed solid image was measured using a commercially available glossiness measuring device (incident angle 75 ± 0.1 °).

Evaluation Criteria A: Excellent with glossiness of 40% or more B: Good with glossiness of 20-40% x: Glossiness of less than 20% and poor practicality.

<Glossy unevenness>
Art paper (manufactured by Mitsubishi Paper Industries, Tokuhishi Art) was used as the recording paper, and the solid images printed out were evaluated visually or with a magnifying glass.

Evaluation Criteria A: Uneven gloss cannot be detected. O: Uneven gloss cannot be detected unless magnified with a loupe. X: Uneven gloss can be visually detected.

  The evaluation results are shown in Table 4.

  As is clear from Table 4, “Examples 1 to 13” corresponding to the present invention are excellent in any evaluation item, but “Comparative Examples 1 to 4” outside the present invention are at least any evaluation item. You can see that there is a problem.

FIG. 3 is a schematic diagram of toner particles according to the present invention. 1 is a cross-sectional configuration diagram illustrating an example of an image forming apparatus in which a toner according to the present invention is preferably used. FIG. 3 is a cross-sectional view illustrating an example of a fixing device used for image formation using the toner according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Semiconductor laser light source 2 Polygon mirror 3 f (theta) lens 4 Photoconductor drum 5 Charging device 6 Developing device 7 Transfer device 8 Transfer paper 9 Separator 10 Fixing device 11 Cleaning device 12 Pre-charge exposure 13 Cleaning blade 71 Heating roller 72 Pressure roller 75 Heating member 81 Heating roller core 82 Heating roller coating layer 83 Pressure roller cored bar 84 Pressure roller coating layer T Toner particles A Resin phase A
B Resin phase B

Claims (11)

A toner comprising a binder resin composed of a copolymer of a plurality of types of vinyl polymerizable monomers, wherein at least one of the copolymers of the plurality of types of vinyl polymerizable monomers is A toner formed using a monomer having two or more polar groups. The toner according to claim 1, wherein the binder resin has a region having a low glass transition temperature. The toner according to claim 1, wherein the region having a low glass transition temperature exists as an independent phase of 50 to 600 nm in the binder resin. The region having a low glass transition temperature is formed by a vinyl copolymer formed using a monomer having two or more polar groups. The toner according to claim 1. The proportion of the vinyl copolymer formed using a monomer having two or more polar groups is 3 to 20% by mass with respect to the total mass of the binder resin. 5. The toner according to any one of 4 above. 6. The toner according to claim 1, wherein the binder resin has a peak molecular weight in the range of 15000 to 25000 and 25000 to 35000, respectively. The toner according to claim 1, wherein the binder resin contains a vinyl copolymer having a dicarboxylic acid monomer as a copolymer component. A toner production method for producing a toner through a step of aggregating a plurality of types of vinyl copolymer particles to form a binder resin, wherein at least one of the plurality of types of vinyl copolymer particles is polar Particles formed using a monomer having two or more groups, and in the step of aggregating the vinyl copolymer particles, particles formed using a monomer having two or more polar groups A method for producing a toner, characterized in that after aggregating each other, other particles agglomerate to form a binder resin. The toner production according to claim 8, wherein the vinyl copolymer particles formed using a monomer having two or more polar groups are formed using a dicarboxylic acid monomer. Method. The glass transition temperature of vinyl copolymer particles formed using a monomer having two or more polar groups is lower than the glass transition temperature of other vinyl copolymer particles. Item 10. The toner production method according to Item 8 or 9. The vinyl copolymer particles formed using the monomer having two or more polar groups and the other vinyl copolymer particles have a difference in solubility parameter value of 0.3 to 1.2. The method for producing a toner according to any one of claims 8 to 10, wherein:

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