JP6417792B2 - Toner set, image forming method, and toner not forming secondary color - Google Patents

Description

  The present invention is a toner (special color) that does not form a secondary color such as white toner, metallic toner, and transparent toner that is transferred / fixed onto a medium (recording medium) together with toner that forms a secondary color (also referred to as color toner). The present invention relates to a toner set using a toner and an image forming method. Further, the present invention relates to a toner that does not form a secondary color and is transferred / fixed on a medium together with a toner that forms a secondary color.

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

  For example, when outputting to special recording media such as colored paper, black paper, aluminum vapor-deposited paper, transparent film, etc., full-color toners such as yellow, magenta, cyan, and black toner are sufficient because of the color characteristics of the recording media. Can not get a good color. Therefore, in order to improve the added value of the image, white toner formed on the lower layer or the upper layer of the image formed by the combination of the above color toners has been developed (for example, see Patent Documents 1 to 4). . In particular, when a transparent film is used as a medium (recording medium), by forming an image with a color toner on a white toner layer, the visibility of the color toner can be improved and the added value as an image can be increased. . Further, by forming a white toner image on colored paper, it is possible to express “white” which is difficult to express with color toner. For this purpose, it is important to increase the hiding ratio of the white toner and further improve the whiteness, and various techniques have been developed (see, for example, Patent Documents 5 to 6).

Furthermore, in order to prevent color mixing of black toner and red toner, the upper and lower toners are mixed by separating the solubility parameter value (SP value: unit (cal / cm ³ ) ^1/2 ) of both toners by 1.0 or more. It is shown that only the color of the toner in the upper layer can be recognized (see, for example, Patent Document 7).

JP 2004-037565 A Patent Document 2: Japanese Patent No. 3960318 JP 2012-189929 A JP 2006-220694 A Japanese Patent Laid-Open No. 1-105962 JP 2000-56514 A Japanese Patent Laid-Open No. 1-262566

  However, in the inventions described in Patent Documents 1 to 6, it has been difficult to form a higher quality image. Therefore, the present inventors considered that it is very important to control the characteristics of white toner and color toner in order to form a higher quality image. However, as a technique for controlling the characteristics of white toner and color toner in order to form a higher quality image, there is nothing about the invention using the SP values of white toner and color toner (binder resin in the toner). The current situation has not been proposed. Here, the toner is mainly composed of a polymer called a binder resin, and has various characteristics depending on its configuration. In general, a polymer is a useful measure for predicting the solubility of a substance because a value inherent to the substance called a solubility parameter value (SP value) can be obtained by calculation.

  On the other hand, in the invention described in Patent Document 7 using the SP values of black toner and red toner from the viewpoint of preventing color mixture, when using a small-diameter toner necessary for high image quality, the surface area of the toner in contact with toners of different colors increases. When the SP value is more than 1.0 (unit omitted), the mixing at the interface becomes too small, and it is not possible to bond sufficiently by heat melting, and the image peels off.

  Therefore, the present invention has good reproducibility of the secondary color of the color image and color bleeding even if a toner layer that does not form a secondary color such as white toner is formed on the upper layer or the lower layer of the full color image. The present invention provides a toner set that can form a high-quality image without peeling, an image forming method, and a toner that does not form a secondary color.

In the present invention, the toner that has the maximum solubility parameter value (SP value: unit (cal / cm ³ ) ^1/2 ) of the binder resin of the toner that forms the secondary color is the first toner, and the toner that has the minimum is the first toner. The second toner and the toner that does not produce a secondary color are defined as the third toner, and the solubility parameter value (SP value: unit (cal / cm ³ ) ^1/2 ) of the binder resin of each of the first to third toners is SP ( 1) When SP (2) and SP (3), the following three formulas:
SP (1) -SP (2) <0.15
0.15 ≦ | SP (1) −SP (3) | <1.0
0.15 ≦ | SP (2) −SP (3) | <1.0
It has the characteristic in the point which satisfy | fills all.

  According to the present invention, the SP value of the binder resin of the toner that forms the secondary color and the binder resin of the toner that forms the secondary color and the toner that does not form the secondary color can be controlled within an appropriate numerical range. Thus, even if a toner layer that does not form a secondary color such as white toner is formed on the upper layer or the lower layer of the full color image, the reproducibility of the secondary color of the color image is good, and “color blur” and “ A high-quality, high-quality value-added image without “image peeling” can be formed.

1 is a schematic sectional view showing an embodiment of an image forming apparatus using the electrophotographic photosensitive member of the present invention.

The first embodiment of the present invention includes a toner that forms a secondary color and a toner that does not form a secondary color (for electrophotographic development used in an image forming apparatus that forms a color toner image by a plurality of developing machines) ) Is a toner set, the solubility parameter value of the binder resin of the toner that forms the secondary color (SP value: (cal / cm ³ ) ^1/2 ; hereinafter, the units in the following formulas (1) to (5) The first toner is the maximum toner, the second toner is the minimum toner, and the third toner is a toner that does not form a secondary color with the toner, and the first to third toners The solubility parameter value of the binder resin (SP value: (cal / cm ³ ) ^1/2 ; hereinafter, units may be omitted in the following formulas (1) to (5), etc.) is SP (1), SP ( 2) and SP (3), the following formula (1) To (3):
SP (1) -SP (2) <0.15 (1)
0.15 ≦ | SP (1) −SP (3) | <1.0 (2)
0.15 ≦ | SP (2) −SP (3) | <1.0 (3),
Preferably the following formulas (1), (4) to (5):
SP (1) -SP (2) <0.15 (1)
0.4 ≦ | SP (1) −SP (3) | <1.0 (4)
0.4 ≦ | SP (2) −SP (3) | <1.0 (5)
1 is a toner set (for electrophotographic development).

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

  The second embodiment of the present invention includes a toner that forms a secondary color and a toner that does not form a secondary color (for electrophotographic development used in an image forming apparatus that forms a color toner image by a plurality of developing machines) ) An image forming method using a toner set, in which the toner having the maximum SP value of the binder resin for forming the secondary color is the first toner, the toner having the minimum is the second toner and the toner and the secondary. When the toner that does not form a color is the third toner and the SP values of the binder resins of the first to third toners are SP (1), SP (2), and SP (3), the above formula (1) ) To (3), preferably satisfying the above formulas (1) and (4) to (5).

  The third embodiment of the present invention relates to a toner and a secondary color that form a secondary color that constitutes a toner set (for electrophotographic development used in an image forming apparatus that forms a color toner image by a plurality of developing machines). In the relationship with the toner not to be formed, the toner having the maximum SP value of the binder resin for forming the secondary color is the first toner, the toner having the minimum is the second toner, and the toner not forming the secondary color with the toner. Is the third toner, and the SP values of the binder resins of the first to third toners are SP (1), SP (2), and SP (3), the above formulas (1) to (3) A toner which does not form a secondary color, preferably satisfying the above formulas (1) and (4) to (5).

  Regarding the configuration requirements of each of the above-described embodiments, the present inventors have intensively studied to solve the above-described problems of the prior art, and as a result, the following technical knowledge (or the theory of the invention (logic: The mechanism of action / mechanism linking issues and effects) was discovered and based on this finding.

  The color toner can form images of various colors by overlapping each toner. Therefore, it is desirable that they fuse well with each other by heat during fixing. On the other hand, in the case of a special color toner, for example, a white toner, it may be used alone for white expression, but it may be formed in an upper layer or a lower layer of the color toner. Therefore, if the color toner is too fused, an image defect referred to as “color blur” occurs particularly in the boundary portion of the image. This is because, for example, white toner and cyan toner are fused when a blue image is formed on a white toner layer by superimposing white toner, cyan toner, and magenta toner on the medium (recording medium) in that order. This results in excessive cyan bleeding at the image boundary.

  On the other hand, the component constituting the toner is mainly a polymer called a binder resin, and the compatibility between the polymers can be explained by the solubility parameter value (SP value). That is, it is known that a substance having a small SP value difference is easily compatible, and a substance having a large SP value difference is hardly compatible. Therefore, the present inventors set the SP value of the binder resin of each toner when forming an image using a toner that forms a secondary color (color toner) and a toner that does not form a secondary color (special color toner). By controlling to a certain range (for details, refer to the above formulas (1) to (5)), it was found that a color toner with high secondary color reproducibility and a high-quality image free from color blur and color blur can be formed. The present invention (each embodiment described above) has been completed.

  Hereinafter, the structure of the characteristic part (common) of each embodiment mentioned above is demonstrated.

(1) Toner forming a secondary color The toner forming a secondary color is a cyan toner containing a cyan colorant (pigment), which is a basic color of a color material used, or a magenta colorant (pigment). ) Containing magenta toner, yellow toner containing yellow colorant (pigment), or black toner containing black colorant (pigment). is there. The toner that forms the secondary color is also referred to as a color toner, and the above-described yellow toner (Y), magenta toner (M), cyan toner (C), and black toner (K) (hereinafter also simply referred to as YMCK). Basic. Such color toners based on YMCK can form images of various colors by superimposing the toners. Therefore, it is desirable that they fuse well with each other by heat during fixing. The binder resin of each toner of the color toner desirably contains a polyester resin that can be fixed at a low temperature. Further, a color toner that requires high image quality is preferably produced by an emulsion association method. The difference in SP value (unit (cal / cm ³ ) ^1/2 ) of the binder resin of each color toner is smaller than 0.15, and it is desirable to fuse well by the heat of fixing. If the difference in SP value is 0.15 or more, the color reproducibility of the secondary color is deteriorated. That is, in the toner (color toner) that forms the secondary color used in each of the above-described embodiments, the difference in SP value of the binder resin of each color toner satisfies the formula (1) described below. In addition, the absolute value of the SP value difference between the binder resins of the color toner and the toner that does not form the secondary color is expressed by the following formulas (2) and (3), preferably formulas (4) and (5). If you satisfy the relationship.

(1-1) Yellow toner (Y)
The yellow toner (Y), which is a kind of toner that forms a secondary color, includes at least a binder resin and a yellow colorant (pigment). Furthermore, you may contain other additives, such as a mold release agent, and an external additive as needed.

(1-2) Magenta toner (M)
The magenta toner (M), which is a kind of toner that forms a secondary color, includes at least a binder resin and a magenta colorant (pigment). Furthermore, you may contain other additives, such as a mold release agent, and an external additive as needed.

(1-3) Cyan toner (C)
The cyan toner (C), which is a kind of toner that forms a secondary color, includes at least a binder resin and a cyan colorant (pigment). Furthermore, you may contain other additives, such as a mold release agent, and an external additive as needed.

(1-4) Black toner (K)
The black toner (K), which is a kind of toner that forms a secondary color, includes at least a binder resin and a black colorant (pigment). Furthermore, you may contain other additives, such as a mold release agent, and an external additive as needed.

(2) Toner that does not form a secondary color The toner that does not form a secondary color is essentially a toner that does not contain a basic colorant (pigment). White toner (W) containing a white colorant (pigment) such as titanium oxide, metallic toner (ME) containing a metallic colorant (pigment) that expresses a metallic luster such as aluminum powder, or a colorant (pigment) Transparent toner (clear toner: (CL)) and the like that do not contain, but are not limited thereto. The toner that does not form a secondary color is also referred to as a special color toner, and is a toner that is used for image formation as a single color other than YMCK that is a toner (color toner) that forms a secondary color, and is also referred to as a spot color. Toners that do not form secondary colors (special color toners) are used to improve the added value of images, and white, metallic, and transparent toners are particularly high-value-added toner groups. Colors that cannot be expressed by the color toner can be expressed, and the color toner can be enhanced in color and gloss by being present in the upper layer and the lower layer of the color toner. In particular, when a transparent film is used as a medium, the visibility of the color toner is improved and the added value as an image can be increased by forming an image with the color toner on the white toner layer. The spot color toner also preferably contains a polyester resin that can be fixed at a low temperature, and is preferably manufactured by an emulsion association method capable of improving image quality. In the case of forming a layer with the color toner, if the difference in SP value between the binder resins of the color toner and the special color toner is too small, “color blur” occurs at the boundary with the color toner, resulting in an image defect. On the other hand, if the difference between the SP values is too large, the adhesion at the interface between the special color toner and the color toner is deteriorated, and image peeling occurs. That is, in the toner that does not form a secondary color (spot color toner) used in each of the above-described embodiments, the absolute value of the difference between the SP value of each binder resin of the spot color toner and the color toner is expressed by the above formula (2). , (3), preferably satisfying the relationship of the formulas (4) and (5). In particular, in the third embodiment, the special color toner is used in the relationship between the color toner and the special color toner constituting the toner set (used in an image forming apparatus that forms a color toner image by a plurality of developing machines). The toner having the maximum SP value of the binder resin is the first toner, the toner having the minimum SP value is the second toner, and the special color toner is the third toner. The SP value of the binder resin of each of the first to third toners is SP. When (1), SP (2), and SP (3) are satisfied, the above formulas (1) to (3), preferably the formulas (1) and (4) to (5) are satisfied. It is. Thereby, the effect of this invention can be show | played effectively.

(2-1) White toner (W)
The white toner (W), which is one kind of toner that does not form a secondary color, includes at least a binder resin and a white colorant (pigment). Furthermore, you may contain other additives, such as a mold release agent, and an external additive as needed. In the present invention, it is preferable that the third toner (special color toner) that is a toner that does not form a secondary color contains a white colorant (pigment) (= white toner). This is because the effect of the special color toner is an added value of the image, and the white toner is one kind of a toner group having a particularly high added value.

(2-2) Metallic toner (ME)
Metallic toner (ME), which is a kind of toner that does not form a secondary color, includes at least a binder resin and a metallic colorant (pigment). Furthermore, you may contain other additives, such as a mold release agent, and an external additive as needed. In the present invention, it is preferable that the third toner (spot color toner) that is a toner that does not form a secondary color contains a metallic colorant (pigment) (= metallic toner). This is because the effect of the special color toner is an added value of the image, and the metallic toner is one kind of a toner group having a particularly high added value.

(2-3) Transparent toner (clear toner: (CL))
The transparent toner (CL), which is a kind of toner that does not form a secondary color, does not contain a colorant (pigment) and contains at least a binder resin. Furthermore, you may contain other additives, such as a mold release agent, and an external additive as needed. The transparent toner (CL) containing no colorant (pigment) can be used for adjusting the gloss of a color image or media. In the present invention, it is preferable that the third toner (spot color toner) that is a toner that does not form a secondary color does not contain a colorant (= transparent toner). This is because the effect of the special color toner is an added value of the image, and the transparent toner is one kind of toner group having a particularly high added value.

(3) Solubility parameter value (SP value: (cal / cm ³ ) ^1/2 )
In the present invention, the solubility parameter value (SP value: (cal / cm ³ ) ^1/2 ) is a solubility parameter value at 25 ° C., which is a value inherent to the substance and is used to predict the solubility of the substance. Is a useful measure. The SP value indicates that the polarity is higher as the numerical value is larger, and the polarity is lower as the numerical value is smaller. When the two types of toner are fused, the degree of fusion increases as the difference in SP value of the binder resin (polymer) that is the main component of the two toners decreases.

(3-1) SP Value Measurement Method The SP value of the binder resin is calculated as the product of the SP value and the molar ratio of each monomer that forms the binder resin. For example, assuming that the binder resin is formed from two types of monomers X and Y, the mass ratio of each monomer is x, y (mass%), and the molecular weight is Mx, My, SP value. Is SPx and SPy, the SP value of the binder resin is expressed by the following formula (6).

  The SP value of a monomer is determined from the evaporation energy (Δei) from “Polym. Eng. Sci. Vol 14. p114 (1974)” proposed by Fedors for atoms or atomic groups in the molecular structure of the monomer. And the molar volume (Δvi) is calculated and calculated from the following formula (7). However, for double bonds that cleave during polymerization, the cleaved state is the molecular structure, and for monomers that form ester bonds, the polyvalent carboxylic acid is calculated with the ester group (—COO—) terminated. The molecular structure to be used was used, and the polyhydric alcohol had a molecular structure to be used for the calculation except for the hydroxyl group. Even when two or more kinds of polymer materials are used as the toner binder resin, the SP value of the toner binder resin is calculated (calculated) by obtaining the monomer structure and molar ratio in the same manner as described above. )can do.

  When the SP value of the monomer cannot be calculated by the above formula (7), as a specific value, documents such as Polymer Handbook (published by Wiley) 4th edition or the independent administrative agency “Materials and Materials Research Organization” Please refer to the item of solubility parameter (http://polymer.nims.go.jp/guide/guide/p5110.html) described in the database “PolyInfo” (http://polymer.nims.go.jp). Can do.

  Further, even from the state of the toner set and the special color toner (that is, the product), the structure and molar ratio of the monomer constituting the binder resin of each toner are qualitatively and quantitatively analyzed, and the calculated ratio is obtained as a calculated value. Similarly to the above, the SP value of the binder resin of the toner can be calculated. It can be determined from the SP value whether the above-described equations (1) to (3) are satisfied.

(4) Formula (1) above; SP (1) -SP (2) <0.15
In the present invention, the difference in the SP value of the binder resin of each toner is important, and a resin synthesized by combining a plurality of general monomers can be used as the material (binder resin). Regarding the SP value (unit (cal / cm ³ ) ^1/2 ) of the binder resin of the toner (color toner) forming the secondary color, the binder resin of each of the first to third toners defined above is used. When the SP value is SP (1), SP (2), SP (3), the difference between SP (1) and SP (2) (SP (1) -SP ( 2)) is preferably smaller than 0.15, and when it is 0.15 or more, the reproducibility of the secondary color is deteriorated. That is, the difference between the SP value (1) and (2) of the first toner that maximizes the SP value of the color toner and the second toner that minimizes the SP value is smaller than 0.15. The binder resin contained in the yellow, magenta, cyan, black toner, etc.) is highly compatible with each other, and even when using a small-diameter toner necessary for high image quality, the color toners are superposed due to superposition. Can fuse with each other very well. As a result, it is possible to form images of various colors with high reproducibility with high definition and high image quality without any problem of image peeling. On the other hand, when the difference between the SP values (1) and (2) of the first toner and the second toner is 0.15 or more, particularly when the small-diameter toner necessary for high image quality is used, the color toners are overlapped. Mixing at the interface cannot be performed sufficiently by heat during fixing. Therefore, the superimposed color toners cannot be sufficiently fused (adhered) to each other by heat melting, resulting in poor color reproducibility of secondary colors (images of various tones), and high-definition and high-quality images. Formation becomes difficult.

(5) The above formula (2); 0.15 ≦ | SP (1) −SP (3) | <1.0, and the above formula (3); 0.15 ≦ | SP (2) −SP (3) | <1.0
In the present invention, the difference in the SP value of the binder resin of each toner is important, and a resin synthesized by combining a plurality of general monomers can be used as the material (binder resin). The SP value of the binder resin of the toner that forms the secondary color (color toner) and the SP value of the binder resin of the toner that does not form the secondary color (special color toner) are the first to third defined above. When the SP value of the binder resin of the toner is SP (1), SP (2), SP (3), as shown in the above formulas (2) to (5), SP (1), (2) and The absolute value of the difference between SP (3) (| SP (1) −SP (3) | and | SP (2) −SP (3) |) is preferably 0.15 or more and smaller than 1.0, Furthermore, since the effect (especially the effect described below) of the present invention is more effective and remarkable, it is more preferable that the value is 0.4 or more and less than 1.0. If the absolute value of the difference between the SP values is smaller than 0.15, the toner that forms the secondary color and the toner that does not form are fused and color blurring occurs. When the absolute value of the difference between the SP values is 1.0 or more, fusion cannot be performed only by thermal fixing, and image peeling occurs. This is because when a small diameter toner required for high image quality is used, the special color toner is formed on the upper layer or the lower layer of the color toner so that the special color toner forms a layer with the color toner, and the color toner and the special color toner are placed on the medium. In the case where the toner is fixed in step (2), the secondary color reproducibility is good and an image free from color toner bleeding is provided. That is, even in the above case, the absolute value of the difference in SP value between the binder resins of the color toner and the special color toner is within the above range (that is, the above formulas (2) and (3), preferably the above formula ( 4) and (5), the visibility of the color toner can be improved without causing “color blur” at the boundary with the color toner. Further, by adding a suitable amount of heat by the heat of heat fixing, it is possible to provide a value-added image in which image peeling does not occur by improving the adhesion at the interface between the special color toner and the color toner. As a result, the color reproducibility of the secondary color is good, and a high-definition, high-quality and high-quality image free from color toner color blur can be provided. On the other hand, if the absolute value of the SP value difference between the binder resins of the color toner and the special color toner is too small, “color blur” occurs at the boundary with the color toner, resulting in an image defect. On the other hand, if the absolute value of the difference between the SP values is too large, it cannot be fused only by heat fixing, the adhesiveness at the interface between the special color toner and the color toner is deteriorated, and image peeling occurs.

  That is, in the above first to third embodiments of the present invention, the toner having the maximum SP value of the binder resin for forming the secondary color (color toner) is the first toner, and the toner having the minimum is the first toner. Two toners and toners that do not produce secondary colors (special color toners) are the third toners, and the SP values of the binder resins of the first to third toners are SP (1), SP (2), SP (3). Where formula (1): SP (1) -SP (2) <0.15, formula (2): 0.15 ≦ | SP (1) −SP (3) | <1.0, and formula (3): 0.15 ≦ | SP (2) −SP (3) | <1.0 is satisfied. By controlling the SP value of the binder resin of the color toner and the binder resin of the color toner and the special color toner so as to satisfy the relationship of the expressions (1) to (3), the secondary value can be obtained. The color reproducibility of the color is good, and it is possible to provide a high-quality, high-quality value-added image without “color blur” and “image peeling” of the color toner. The characteristic portions of the first to third embodiments of the present invention have been described above. Hereinafter, the configuration of each toner of a toner that forms a secondary color (color toner) and a toner that does not generate a secondary color (special color toner) will be described.

(6) Average particle diameter of each toner In the present invention, a small diameter toner required for high image quality is used for each toner of a toner that forms a secondary color (color toner) and a toner that does not generate a secondary color (special color toner). Therefore, the average particle diameter of each toner is preferably 4 to 10 μm, and more preferably 5 to 8 μm. If the average particle size of each toner is 4 μm or more, the fluidity will not be deteriorated, so that it is preferable in terms of easy use (workability, handling, etc.) in the electrophotographic process. Further, if the average particle diameter of each toner is 10 μm or less, the surface area of the toners in contact with each other does not become small, so that it can be used as a small diameter toner necessary for high image quality. In particular, when the special color toner is formed on the upper layer or the lower layer of the color toner so that the special color toner forms a layer with the color toner, and the color toner and the special color toner are fixed on the medium, the SP value of the color toner and the special color toner is changed. By making the absolute value of the difference smaller than 1.0 (satisfying the above formulas (2) and (3)), sufficient adhesion can be obtained only by heat fixing, and the color reproducibility of the secondary color is good. This is preferable in that an image free from toner color blur can be provided. The average particle diameter of each toner can be measured using the method described in “1. Average particle diameter of toner” in <Measurement / Calculation Method> in the Examples. In addition, it can obtain | require similarly about the average particle diameter of the following various particles.

(7) Shape factor of each toner In the present invention, a spherical small-diameter toner necessary for high image quality is used for each toner of a toner that forms a secondary color (color toner) and a toner that does not generate a secondary color (special color toner). Since it is more preferable to use the toner, the shape factor of each toner is preferably 0.910 to 0.995, and more preferably 0.930 to 0.985. If the shape factor of each toner is 0.910 or more, it is preferable because high transfer efficiency can be obtained. In addition, it is preferable that the shape factor of each toner is 0.995 or less because good cleaning properties can be obtained. The shape factor of each toner can be measured using the method described in “2. Toner shape factor” of <Measurement / Calculation Method> in the Examples.

(8) Constituent Members of Each Toner In the present invention, the constitution of each toner of a toner that forms a secondary color (color toner) and a toner that does not produce a secondary color (special color toner) is described in (1-1) above. As described with respect to YMCK of color toner in (1-4), and W, ME, and CL of special color toners in (2-1) to (2-3), each toner is a main component. It contains a binder resin and each colorant (CL does not contain a colorant (pigment)), and further contains other additives such as a release agent and external additives as necessary. Hereinafter, each component will be described.

(8-1) Colorant As the colorant (pigment) used for each toner (excluding CL), carbon black, magnetic material, dye, pigment, and the like can be arbitrarily used. Furnace black, acetylene black, thermal black, lamp black, etc. are used. Magnetic materials include ferromagnetic metals such as iron, nickel and cobalt, alloys containing these metals, compounds of ferromagnetic metals such as ferrite and magnetite, alloys that do not contain ferromagnetic metals but exhibit ferromagnetism by heat treatment, For example, a kind of alloy called Heusler alloy such as manganese-copper-aluminum and manganese-copper-tin, chromium dioxide, and the like can be used.

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

  The metallic colorant (pigment) used in the metallic toner (ME) means a material capable of obtaining a metallic tone, and not only a conductive metallic material but also a non-metallic material, and a non-metallic material. A conductive material is also included. Examples of the metallic colorant (pigment) include aluminum pigment (aluminum powder; aluminum or its alloy powder), bronze powder, pearl pigment, and the like.

  Examples of the black colorant (pigment) used for the black toner (K) include carbon black such as furnace black, channel black, acetylene black, thermal black, and lamp black, and magnetic powder such as magnetite and ferrite. .

  Examples of the magenta or red colorant (pigment) used in the magenta toner (M) are C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48; 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 150, C.I. I. Pigment red 166, C.I. I. Pigment red 177, C.I. I. Pigment red 178, pigment red 184, C.I. I. Pigment red 222, C.I. I. Pigment red 238 and the like.

  Examples of the colorant (pigment) for orange or yellow used for yellow toner (Y) and the like include C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 155, C.I. I. Pigment yellow 180, C.I. I. And CI Pigment Yellow 185.

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

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

  The content of the colorant (pigment) is in the range of 1 to 60% by mass, preferably 2 to 40% by mass, based on the total toner, and a mixture thereof can also be used. Within such a range, the color reproducibility of the image can be ensured.

  Moreover, as a magnitude | size of a coloring agent (particle | grain), 10-1000 nm and 50-500 nm are preferable at a volume average particle diameter, Furthermore, 80-300 nm is especially preferable. Within such a range, high color reproducibility can be obtained, and it is preferable in that it is suitable for forming a small diameter toner required for high image quality. The volume average particle diameter of the colorant (particles) can be measured using the method described in “2. Toner shape factor” in <Measurement / calculation method> in the examples. The volume average particle diameter of resin particles such as the following binder resins and various particles such as a release agent (particles) can be determined in the same manner as described above.

(8-2) Binder Resin As the binder resin that is the main component of each toner, conventional resins used for toners can be used. For example, polyester resin; styrene such as polyvinyl toluene and its substitutes Polymers of: styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-acrylic acid Ethyl copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, Styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer Polymer, Styrene-vinyl methyl ketone copolymer, Styrene-butadiene copolymer, Styrene-isoprene copolymer, Styrene-acrylonitrile-indene copolymer, Styrene-maleic acid copolymer, Styrene-maleic acid ester copolymer Styrene copolymers such as: polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, polyacrylic acid resin, rosin, modified Examples thereof include rosin, terpene resin, aliphatic or alicyclic hydrocarbon resin, and aromatic petroleum resin.

  From the viewpoint of low-temperature fixability for fixing the toner image at a low temperature, it is preferable to use at least a polyester resin as the binder resin. Here, among the toner that forms a secondary color (color toner) and the toner that does not form a secondary color (special color toner), at least the color toner preferably contains a polyester resin, and both the color toner and the special color toner are polyester. More preferably, it contains a resin. From the viewpoint of low-temperature fixability and heat-resistant storage stability of the toner, an amorphous resin (particularly an amorphous polyester resin) is used as the binder resin, or an amorphous resin and a crystalline polyester resin are used in combination. It is preferable to use a combination of an amorphous polyester resin and a crystalline polyester resin.

(8-2a) Amorphous resin The amorphous resin is not particularly limited, but is preferably an amorphous polyester resin obtained by condensing a polyhydric alcohol component and a polyvalent carboxylic acid component.

  The amorphous polyester resin is a polyester resin other than the crystalline polyester resin. That is, normally, it does not have a melting point (a clear endothermic peak in a DSC curve measured using a differential scanning calorimetry (DSC) measuring device) and has a relatively high glass transition temperature (Tg). More specifically, the Tg of the amorphous resin (particularly the amorphous polyester resin) by the differential scanning calorimeter is preferably 40 to 90 ° C, and particularly preferably 45 to 80 ° C. A Tg of an amorphous resin (particularly an amorphous polyester resin) within the above range is preferable because low-temperature fixability, fixing separation property, and image storage resistance can be appropriately obtained. The Tg of an amorphous resin (particularly an amorphous polyester resin) is the onset temperature of the amorphous resin measured by DSC. For example, the Tg of an amorphous resin (particularly an amorphous polyester resin) can be obtained using a differential scanning calorimeter in accordance with ASTM D3418. The temperature correction of the detection part of this apparatus uses the melting point of indium and zinc, and the correction of heat quantity uses the heat of fusion of indium. For the sample, an aluminum pan was used, an empty pan was set as a control, the temperature was increased at a temperature increase rate of 10 ° C./min, held at 200 ° C. for 5 minutes, and liquid nitrogen was used from 200 ° C. to 0 ° C. The temperature is lowered at 10 ° C./min, held at 0 ° C. for 5 minutes, and again heated from 0 ° C. to 200 ° C. at 10 ° C./min. The analysis is performed from the endothermic curve during the second temperature increase, and the onset temperature of the amorphous resin (particularly the amorphous polyester resin) is defined as Tg.

  The weight average molecular weight (Mw) of the amorphous resin (particularly amorphous polyester resin) by gel permeation chromatography analyzer (GPC) is preferably 3000 to 100,000, more preferably 4000 to 70000. When the weight average molecular weight (Mw) of the amorphous resin (especially the amorphous polyester resin) is in such a range, the resulting toner has excellent blocking resistance and low temperature fixability.

  The polyhydric alcohol component used for the synthesis (condensation) of the amorphous polyester resin is not particularly limited, and examples thereof include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-dodecanediol, 1,11-undecanediol, 1 , 12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, 1,20-eicosanediol, and the like; bisphenols such as bisphenol A and bisphenol F , And these ethylene oxide adducts, propylene oxide Etc. can be mentioned alkylene oxide adducts of bisphenols, such as adduct As the trihydric or higher polyhydric alcohol components, glycerin, trimethylolpropane, pentaerythritol, sorbitol and the like. Furthermore, cyclohexane dimethanol, cyclohexane diol, neopentyl alcohol, or the like may be used from the viewpoint of production cost and environmental properties. Examples of the polyhydric alcohol component capable of forming an amorphous polyester resin include unsaturated polyvalent compounds such as 2-butyne-1,4 diol, 3-butyne-1,4 diol, and 9-octadezene-7,12 diol. Alcohol and the like can also be used. These polyhydric alcohol components may be used alone or in combination of two or more.

  Among these, from the viewpoint of chargeability and toner strength, it is preferable to use an ethylene oxide adduct of bisphenol A and / or a propylene oxide adduct of bisphenol A as the polyhydric alcohol component. The number of moles of ethylene oxide or propylene oxide added is preferably in the range of 1 to 20 moles and more preferably in the range of 1 to 10 moles from the viewpoint of the completion of the stable polycondensation reaction.

  Examples of the divalent carboxylic acid component condensed with the polyhydric alcohol component include aromatic carboxylic acids such as terephthalic acid, isophthalic acid, phthalic anhydride, trimellitic anhydride, pyromellitic acid, and naphthalenedicarboxylic acid; Acid, fumaric acid, succinic acid, alkenyl succinic acid, adipic acid, peric acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,10-dodecanedicarboxylic acid (1, 10-dodecanedioic acid), 1,12-dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, aliphatic carboxylic acids such as 1,18-octadecanedicarboxylic acid; alicyclic carboxylic acids such as cyclohexanedicarboxylic acid; and these And lower alkyl esters of acids, acid anhydrides, and the like. May be used alone or two or more.

  Among these polyvalent carboxylic acids, especially when alkenyl succinic acid or its anhydride is used, it is more easily compatible with crystalline polyester resin due to the presence of alkenyl groups having higher hydrophobicity than other functional groups. Can do. Examples of alkenyl succinic acid components include n-dodecyl succinic acid, n-dodecenyl succinic acid, isododecyl succinic acid, isododecenyl succinic acid, n-octyl succinic acid, n-octenyl succinic acid, and anhydrides thereof, Examples thereof include acid chlorides and lower alkyl esters having 1 to 3 carbon atoms.

  Further, by containing a trivalent or higher carboxylic acid, the polymer chain can take a crosslinked structure, and by taking the crosslinked structure, a decrease in elastic modulus on the high temperature side can be suppressed. The offset property on the side can be improved.

  Examples of the trivalent or higher carboxylic acid include trimellitic acid such as 1,2,4-benzenetricarboxylic acid and 1,2,5-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, and hemimerlic acid. , Trimesic acid, merophanic acid, planitic acid, pyromellitic acid, meritic acid, 1,2,3,4-butanetetracarboxylic acid, and their acid anhydrides, acid chlorides and lower alkyl esters having 1 to 3 carbon atoms Among them, trimellitic acid (anhydride) is particularly preferable. These may be used individually by 1 type and may use 2 or more types together.

  The softening temperature of the amorphous polyester resin is preferably 70 to 140 ° C, and more preferably 70 to 125 ° C. Such a range is preferable in terms of obtaining low-temperature fixing and appropriate gloss. The softening temperature of the amorphous polyester resin can be determined by a flow tester or the like.

  Moreover, it is preferable that the acid value of an amorphous polyester resin is 5-45 mgKOH / g, More preferably, it is 5-30 mgKOH / g. If the acid value is 45 mgKOH or less, the hygroscopicity is not increased, and it is preferable in that the chargeability can be prevented from being lowered even under high humidity. Further, if it is 5 mgKOH / g or more, it is preferable in that the dispersion stability of the resin particles can be maintained and the toner can be easily produced. Here, the acid value represents the mass of potassium hydroxide (KOH) necessary for neutralizing the acid contained in 1 g of the polyester resin in mg. The acid value of the polyester resin can be determined according to JIS K0070-1966. Hereinafter, the acid values of other resins can be determined in the same manner as described above.

  Examples of the amorphous resin include an amorphous polyester resin and a styrene-acrylene resin described in JP 2011-197659 A.

  Amorphous resins, in particular amorphous polyester resins, can be synthesized using any known combination of the above-described constituent components using a conventionally known method. A transesterification method, a direct polycondensation method, etc. can be used alone. Further, they can be used in combination.

  Specifically, the polymerization can be carried out at a polymerization temperature of 140 ° C. or higher and 270 ° C. or lower. The reaction system is reduced in pressure as necessary, and the reaction is carried out while removing water and alcohol generated during the condensation. When the monomer is not dissolved or compatible at the reaction temperature, a solvent having a high boiling point may be added as a solubilizing solvent and dissolved. In the polycondensation reaction, the dissolution auxiliary solvent is distilled off. In the case where a monomer having poor compatibility exists in the copolymerization reaction, it is preferable that the monomer having poor compatibility and the monomer and the acid or alcohol to be polycondensed are condensed in advance and then polycondensed together with the main component.

  The ratio of the polyhydric alcohol component (particularly diol component) to the polyhydric carboxylic acid component (particularly dicarboxylic acid component) is such that the hydroxyl group [OH] of the polyhydric alcohol component and the carboxyl group [COOH of the polycarboxylic acid component] The equivalent ratio [OH] / [COOH] is preferably 1.5 / 1 to 1 / 1.5, more preferably 1.2 / 1 to 1 / 1.2. When the use ratio of the polyhydric alcohol component and the polycarboxylic acid component is in the above range, an amorphous polyester resin having a desired molecular weight can be obtained with certainty.

  Catalysts that can be used in the production of amorphous resins, particularly amorphous polyester resins, include titanium monocarboxylates such as titanium acetate, titanium propionate, titanium hexanoate, and titanium octoate, titanium oxalate, and succinic acid. Titanium dicarboxylates such as titanium oxide, titanium maleate, titanium adipate, and titanium sebacate, titanium tricarboxylates such as hexanetricarboxylic acid titanium, isooctanetricarboxylic acid, octanetetracarboxylic acid titanium, decane tetracarboxylic acid titanium, etc. Aliphatic carboxylic acid titanium such as Titanium aliphatic polycarboxylic acid, Titanium monocarboxylic acid titanium such as Titanium benzoate, Titanium phthalate, Titanium terephthalate, Titanium isophthalate, Titanium naphthalene dicarboxylate, Titanium biphenyl dicarboxylate A Aromatic dicarboxylic acid titanium such as titanium tetracene dicarboxylate; Aromatic tricarboxylic acid titanium such as trimellitic acid titanium and naphthalene tricarboxylic acid titanium; Aromatic tetracarboxylic acid titanium such as benzene tetracarboxylic acid titanium and naphthalene tetracarboxylic acid titanium; etc. Titanium aromatic carboxylic acids, titanyl compounds of aliphatic carboxylic acid titanium and aromatic carboxylic acid titanium, and alkali metal salts thereof, titanium halides such as dichlorotitanium, trichlorotitanium, tetrachlorotitanium and tetrabromotitanium , Tetrabutoxy titanium (titanium tetrabutoxide), tetraalkoxy titanium such as tetraoctoxy titanium, tetrastearyloxy titanium, titanium acetylacetonate, titanium diisopropoxide bisacetyl Acetonate, titanium triethanol aluminate, titanium-containing catalysts, such as.

  The amount of the catalyst that can be used in the production of the amorphous resin, particularly the amorphous polyester resin, is preferably in the range of 0.01 to 10.0% by mass with respect to the total amount of monomers during resin synthesis, A range of 0.02 to 7.0% by mass is more preferable. Such a range is preferable in that no unreacted monomer remains.

  The content of the amorphous resin (particularly the amorphous polyester resin) is usually 50 to 95% by mass, preferably 50 to 80% by mass with respect to the total toner (100% by mass). When the toner is in such a range, the obtained toner has excellent blocking resistance and low temperature fixability.

(8-2b) Crystalline polyester resin The crystalline polyester resin is not particularly limited, and is the weight of a divalent or higher carboxylic acid (polyvalent carboxylic acid) and a divalent or higher alcohol (polyhydric alcohol). A wide range of known polyester resins obtained by condensation reactions can be applied. Here, the crystalline polyester resin refers to a resin having a clear endothermic peak instead of a stepwise endothermic change in differential scanning calorimetry (DSC) among the above-described polyester resins. Specifically, the endothermic peak has a half-value width of 15 ° C. or less when measured at a rate of temperature increase of 10 ° C./min in the differential scanning calorimetry (DSC) described in the examples. It means a peak. The non-crystalline polyester resin refers to a polyester resin other than the crystalline polyester resin (having no clear endothermic peak as described above) among the polyester resins.

  The crystalline polyester resin is not particularly limited as long as it is defined above. For example, for a resin having a structure in which other components are copolymerized on the main chain of the crystalline polyester resin, the resin is clear as described above. If it shows an endothermic peak, it corresponds to the crystalline polyester resin referred to in the present invention.

  The weight average molecular weight (Mw) of the crystalline polyester resin by gel permeation chromatography analyzer (GPC) is preferably 2,000 to 20,000. Within such a range, the resulting toner particles do not have a low melting point as a whole and are excellent in blocking resistance and excellent in low-temperature fixability.

  The melting point (Tm) of the crystalline polyester resin measured by a differential scanning calorimeter (DSC) is preferably 50 ° C. or higher and lower than 120 ° C., more preferably 60 ° C. or higher and lower than 90 ° C. It is preferable for the melting point of the polyester resin to be in the above-mentioned range since low-temperature fixability and fixability can be appropriately obtained. Regarding the melting point of the crystalline polyester resin, the endothermic peak temperature measured by DSC is defined as the melting point of the crystalline polyester resin. For example, the Tm of the crystalline polyester resin can be obtained using a differential scanning calorimeter in accordance with ASTM D3418. The temperature correction of the detection part of this apparatus uses the melting point of indium and zinc, and the correction of heat quantity uses the heat of fusion of indium. For the sample, an aluminum pan was used, an empty pan was set as a control, the temperature was increased at a temperature increase rate of 10 ° C./min, held at 200 ° C. for 5 minutes, and liquid nitrogen was used from 200 ° C. to 0 ° C. The temperature is lowered at 10 ° C./min, held at 0 ° C. for 5 minutes, and again heated from 0 ° C. to 200 ° C. at 10 ° C./min. By analyzing from the endothermic curve at the second temperature rise, the endothermic peak temperature can be calculated from the maximum peak of the crystalline polyester resin, and the endothermic peak temperature can be defined as Tm.

  The acid value (acid value AV) of the crystalline polyester resin is preferably 5 to 45 mgKOH / g, more preferably 5 to 30 mgKOH / g. If the acid value is 45 mgKOH or less, the hygroscopicity is not increased, and it is preferable in that the chargeability can be prevented from being lowered even under high humidity. Further, if it is 5 mgKOH / g or more, it is preferable in that the dispersion stability of the resin particles can be maintained and the toner can be easily produced.

  The crystalline polyester resin is produced from a polyvalent carboxylic acid component and a polyhydric alcohol component. The valences of the polyvalent carboxylic acid component and the polyhydric alcohol component are each preferably 2 to 3, particularly preferably 2 respectively. Therefore, when the valence is 2 respectively as a particularly preferable form (that is, dicarboxylic acid) The acid component and diol component) will be described.

  As the dicarboxylic acid component, an aliphatic dicarboxylic acid is preferably used, and an aromatic dicarboxylic acid may be used in combination. As the aliphatic dicarboxylic acid, it is preferable to use a linear one. By using a linear type, there is an advantage that crystallinity is improved. The dicarboxylic acid component is not limited to one type, and two or more types may be mixed and used. As the aliphatic dicarboxylic acid, it is more preferable to use a linear aliphatic dicarboxylic acid having 2 to 22 carbon atoms constituting the main chain.

  Examples of the aliphatic dicarboxylic acid include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, and 1,10-decanedicarboxylic acid. Acid, 1,10-dodecanedicarboxylic acid (1,10-dodecanedioic acid), 1,11-undecanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,13-tridecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid Examples thereof include acids, 1,16-hexadecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, and the like, and lower alkyl esters and acid anhydrides thereof can also be used.

  Among the above aliphatic dicarboxylic acids, from the viewpoint of easy availability, linear aliphatic dicarboxylic acids having 6 to 14 carbon atoms are preferable, and adipic acid and 1,8-octane dicarboxylic acid are preferable. 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, and 1,10-dodecanedicarboxylic acid (1,10-dodecanedioic acid) are more preferable.

  Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, orthophthalic acid, t-butylisophthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4′-biphenyldicarboxylic acid, and the like. Among these, terephthalic acid, isophthalic acid, and t-butylisophthalic acid are preferably used from the viewpoints of availability and emulsification ease.

  The amount of the aliphatic dicarboxylic acid used is preferably 80 component mol% or more, more preferably 90 component mol%, based on 100 mol% of the entire dicarboxylic acid component for forming the crystalline polyester resin. More preferably, it is 100 constituent mol%. When the amount of the aliphatic dicarboxylic acid used is 80 constituent mol% or more, the crystallinity of the crystalline polyester resin can be ensured and excellent low-temperature fixability can be obtained in the manufactured toner. Glossiness is obtained in the formed image, and deterioration of image storage stability due to melting point depression is suppressed. Furthermore, when oil droplets are formed using an oil phase liquid containing the crystalline polyester resin, it is surely emulsified. Can be obtained.

  Moreover, it is preferable to use aliphatic diol as a diol component, and you may contain diols other than aliphatic diol as needed. As the diol component, it is more preferable to use a linear aliphatic diol having 2 to 22 carbon atoms constituting the main chain among the aliphatic diols.

  Examples of the aliphatic diol include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8- Octanediol, 1,9-nonanediol, 1,10-dodecanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18- Examples include octadecanediol and 1,20-eicosanediol. Among these, those having 2 to 14 carbon atoms constituting the main chain are preferable from the viewpoints of availability and reliable low-temperature fixability.

  As the diol component, a branched aliphatic diol can also be used. In this case, from the viewpoint of ensuring crystallinity, it is used together with a linear aliphatic diol and the linear aliphatic diol. It is preferable to use at a higher ratio. By using the linear aliphatic diol in such a high proportion, it is possible to reliably obtain excellent low-temperature fixability in a toner manufactured with ensured crystallinity, and finally form an image. In this case, a decrease in image storability due to a decrease in melting point is suppressed, and further, blocking resistance can be reliably obtained.

  A diol component may be used individually by 1 type and may be used 2 or more types.

  As the diol component for forming the crystalline polyester resin, the content of the aliphatic diol is preferably 80 component mol% or more, more preferably 90 component mol% or more, and still more preferably 100 component mol%. %. When the content of the aliphatic diol in the diol component is 80 constituent mol% or more, the crystallinity of the crystalline polyester resin can be ensured, and excellent low-temperature fixability can be obtained in the manufactured toner. Glossiness can be obtained in an image formed automatically.

  Examples of the diol other than the aliphatic diol include a diol having a double bond and a diol having a sulfonic acid group. Specifically, examples of the diol having a double bond include 2-butene-1,4. -Diol, 3-butene-1,6-diol, 4-butene-1,8-diol and the like. The content of the diol having a double bond in the diol component is preferably 20 constituent mol% or less.

  In addition, monovalent acids such as acetic acid and benzoic acid, monovalent alcohols such as cyclohexanol and benzyl alcohol, benzenetricarboxylic acid, naphthalenetricarboxylic acid, etc. , And their anhydrides and their lower alkyl esters, glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol can also be used in combination.

  The crystalline polyester resin can be synthesized by using a conventionally known method in any combination among the above-described constituent components, and can be used alone or in combination, such as a transesterification method or a direct polycondensation method. it can.

  Specifically, the polymerization can be carried out at a polymerization temperature of 140 ° C. or higher and 270 ° C. or lower. The reaction system is reduced in pressure as necessary, and the reaction is carried out while removing water and alcohol generated during the condensation. When the monomer is not dissolved or compatible at the reaction temperature, a solvent having a high boiling point may be added as a solubilizing solvent and dissolved. In the polycondensation reaction, the dissolution auxiliary solvent is distilled off. In the case where a monomer having poor compatibility exists in the copolymerization reaction, it is preferable that the monomer having poor compatibility and the monomer and the acid or alcohol to be polycondensed are condensed in advance and then polycondensed together with the main component.

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

  As the catalyst that can be used in the production of the crystalline polyester resin, the same catalyst that can be used in the production of the amorphous polyester resin can be used.

  The content of the crystalline polyester resin is usually 1 to 40% by mass, preferably 5 to 20% by mass with respect to the whole toner (100% by mass). When the addition amount of the crystalline polyester resin is 40% by mass or less, the occurrence of burying or filming of the external additive is small. When the content is 1% by mass or more, the effect of improving the low-temperature fixability can be effectively obtained.

  Further, as described above, each toner may contain an internal additive such as a release agent and a charge control agent; and an external additive such as inorganic fine particles, organic fine particles, and a lubricant, as necessary. .

(8-3) Release agent (wax)
The release agent constituting each toner is not particularly limited, and known ones can be used. Specifically, for example, low molecular weight polyolefins such as polyethylene, polypropylene and polybutene; plant waxes such as synthetic ester wax, carnauba wax, rice wax, candelilla wax, wood wax, jojoba oil; montan wax, paraffin wax , Minerals such as microcrystalline wax and Fischer-Tropsch wax, petroleum-based wax; and modified products thereof. These release agents may be used alone or in combination of two or more.

  The content of the releasing agent is usually 0.5 to 25% by mass, preferably 3 to 20% by mass with respect to the whole toner (100% by mass). Within such a range, there are effects of preventing hot offset and ensuring separability.

  The size of the release agent (particles) in the case of obtaining each toner by the emulsion association method (emulsion aggregation method) is preferably 10 to 1000 nm and 50 to 500 nm, more preferably 80 to 300 nm in terms of volume average particle diameter. Is particularly preferred. Within such a range, when the release agent is melted, it is easy to elute to the image surface, which is preferable in terms of image separation.

(8-4) Charge control agent Various known compounds can be used as the charge control agent. Examples of the charge control agent include a nigrosine-based electron-donating dye, a metal salt of naphthenic acid or higher fatty acid, an alkoxylated amine, a quaternary ammonium salt, an alkylamide, a metal complex, a pigment, and a fluorine treatment activity. Examples of agents for negative charging include electron-accepting organic complexes, chlorinated paraffins, chlorinated polyesters, and sulfonylamines of copper phthalocyanine.

  The content of the charge control agent is usually 0.1 to 10 parts by mass, preferably 0.5 to 5 parts by mass with respect to 100 parts by mass of the binder resin in the finally obtained toner particles. . Such a range is preferable in that a charge rising after toner replenishment can be secured.

(8-5) External additives From the viewpoint of improving the charging performance, fluidity, and cleaning properties of the toner, particles such as known inorganic fine particles and organic fine particles and a lubricant are added as external additives to the surface of the toner particles. Can do.

  Preferred inorganic fine particles include inorganic fine particles made of silica, titania, alumina, strontium titanate, or the like.

  It is desirable that these inorganic fine particles are subjected to a hydrophobic treatment as necessary. In the present invention, hydrophobic silica is preferred from the viewpoint of high chargeability among the inorganic fine particles subjected to the hydrophobic treatment. Such hydrophobic silica may be produced (in-house production), or commercially available products such as hydrophobic fumed silica and hydrophobic sol-gel silica may be obtained.

  The average particle diameter of the inorganic fine particles (including those subjected to hydrophobic treatment) is preferably 10 to 700 nm, and more preferably 10 to 500 nm. Such a range is preferable in that a stable image can be obtained through durability. Further, the shape of the inorganic fine particles (including those subjected to hydrophobic treatment) is not particularly limited, and those having an arbitrary shape such as a spherical shape or an indefinite shape can be used.

  As the organic fine particles, spherical organic fine particles having a number average primary particle diameter of about 10 to 2000 nm can be used. Such a range is preferable in that a stable image can be obtained through durability. Specifically, organic polymers such as homopolymers such as styrene and methyl methacrylate and copolymers thereof can be used. The number average primary particle diameter of the organic fine particles is measured by an image analysis method. Specifically, using a scanning electron microscope “JSM-7401 (manufactured by JEOL)”, a photograph of the toner is taken at a magnification of 30,000 times, the photograph image is captured by a scanner, and an image processing analysis apparatus “LUZEX ( (Registered trademark) AP "(manufactured by Nireco Corporation) software version Ver. 1.32 is used to binarize the organic fine particles on the photographic image, the horizontal ferret diameter is calculated for any 100 organic fine particles, and the average value is the number average primary particle diameter. Here, the horizontal ferret diameter means the length of a side parallel to the x-axis of the circumscribed rectangle when the image of the external additive is binarized. When the aggregate is present on the toner surface, the number average primary particle diameter of the primary particles forming the aggregate is measured. In addition, the number average primary particle diameters of the following various particles can be determined in the same manner as described above.

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

  The content of the external additive is preferably from 0.1 to 10.0% by mass, and preferably from 0.5 to 8.0% by mass, based on the entire toner particles (including the external additive). Such a range is preferable in that a stable image can be obtained through durability.

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

(8-5a) Surface Abundance Ratio of “Hydrophobic Silica” Included in External Additive In the present invention, each toner of the first toner, the color toner including the second toner, and the third toner (special color toner) is ( Surface elemental silicon content A measured by X-ray photoelectron spectroscopy (XPS) of the first toner, the second toner, and the third toner (special color toner) containing hydrophobic silica (as an external additive) The third toner (special color toner) has a larger ratio (A / B) of (atom%) to the carbon element content B (atom%) than the color toner including the first toner and the second toner. Is desirable. That is, each toner (color toner and special color toner) usually contains hydrophobic silica as an external additive. In this case, the ratio of Si to C (Si / C) (= A / B) on the toner surface measured by the XPS method is preferably larger for the special color toner than for the color toner. It can be said that the presence of “hydrophobic silica” contained in the external additive inhibits the fusion of the resin between the toners to some extent. Therefore, when the SP value (the absolute value of the difference) between the special color toner and the color toner is within the range of the present invention (satisfying the relations of the above formulas (2) to (3)), the special color toner is more effective than the color toner. It can be said that the presence of a large amount of “hydrophobic silica” on the surface can suppress the occurrence of color bleeding more effectively. From this point of view, the third value is larger than the maximum value (A / B) of the color toner including the first toner and the second toner (that is, the toner having the largest (A / B) among YMCK and the like). The toner (spot color toner) (A / B) is preferably larger in the range of 0.01 to 0.8, more preferably in the range of 0.1 to 0.7.

  The (A / B) of the color toner including the first toner and the second toner is preferably in the range of 0.15 to 0.50, more preferably 0.20 to 0.50. Such a range is preferable in that an appropriate charge amount can be maintained without affecting the fusion of colors. On the other hand, the (A / B) of the third toner (spot color toner) is preferably in the range of 0.30 to 1.0, more preferably 0.40 to 0.90. Such a range is preferable in that an appropriate charge amount can be maintained while suppressing the occurrence of color bleeding.

(8-5b) Method for measuring surface abundance ratio of hydrophobic silica contained in external additive (XPS method)
The ratio between the number of silicon atoms and the number of carbon atoms on the toner surface can be measured by an X-ray photoelectron spectroscopy (XPS) analyzer. The X-ray photoelectron spectroscopy (XPS) analyzer analyzes the atoms contained in the sample and their electronic states by irradiating the surface of the toner sample with X-rays and measuring the energy of the generated photoelectrons. The mechanism is that when the material is irradiated with X-rays, the electrons in the atomic orbitals are excited and discharged out of the atomic orbitals as photoelectrons. Here, since the photoelectron has an energy value according to E = hv-EB (EB is the binding energy of the electron), the X-ray energy is constant, that is, if it is a single wavelength X-ray, The binding energy represented by EB can be obtained. Since the electron binding energy is orbital energy specific to each atom, the type of atom can be identified from this value. In the present invention, the ratio of the number of silicon (Si) atoms and the number of carbon (C) atoms on the toner surface can be calculated by a known X-ray photoelectron spectroscopy (XPS) analyzer.

(9) Toner Production Method The method for producing each toner (color toner and special color toner) is not particularly limited, and kneading and pulverization method, suspension polymerization method, emulsion association method (emulsion aggregation method), dissolution suspension method. And publicly known methods such as a polyester elongation method and a dispersion polymerization method. In these toner production methods, in the present invention, the SP value of the binder resin of the color toner and the special color toner has the above formulas (1) to (3), preferably the formulas (1) and (4) to (5). What is necessary is just to select suitably binder resin (further each monomer which forms binder resin) so that it may be satisfied. That is, regarding the SP value of the binder resin (and each monomer forming the binder resin) of the color toner and the special color toner of the present invention, the above “(3-1) SP value measurement method (Fedors method etc.) ) ”In advance, the SP value of the binder resin of each toner (and each monomer that forms the binder resin) is calculated in advance, and the above formulas (1) to (3), preferably the formula (1), After confirming that (4) to (5) are satisfied, a binder resin (and further a binder) of the color toner and the special color toner is added to the kneading and pulverization method and the emulsion association method (emulsion aggregation method) described below. Each monomer that forms a resin) may be used.

  Further, at least the color toner is preferably produced by an emulsion association method (emulsion aggregation method) from the viewpoints of particle size uniformity, shape controllability, and ease of core-shell structure formation. Hereinafter, a method for producing a toner by an emulsion association method (emulsion aggregation method) will be described in detail, but the present invention is not limited thereto.

(9-1) Emulsion association method (emulsion aggregation method)
The emulsion association method (emulsion aggregation method) is a method in which the binder resin dispersed by a surfactant or a dispersion stabilizer (in the present invention, the SP value of the binder resin of the color toner and the special color toner is expressed by the above formulas (1) to ( 3) and a dispersion of fine particles (hereinafter also referred to as “resin fine particles”) with a dispersion of toner particle constituents such as fine particles of a colorant, and an aggregating agent is added. In this method, the toner particles are aggregated (aggregated) until a desired toner particle size is obtained, and thereafter or simultaneously with the aggregation (association), the resin fine particles are fused to form toner particles.

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

  The resin fine particles can be produced, for example, by an emulsion polymerization method, a miniemulsion polymerization method, a phase inversion emulsification method, or the like, or can be produced by combining several production methods. When an internal additive is contained in the resin fine particles, it is preferable to use a miniemulsion polymerization method.

  When an internal additive is contained in the toner particles, the resin fine particles may contain an internal additive, or a dispersion of internal additive fine particles consisting of only the internal additive is separately prepared and the internal additive is added. The agent fine particles may be aggregated (aggregated) together with the resin fine particles.

  In addition, toner particles having a core-shell structure can be obtained by an emulsion association method (emulsion aggregation method). Specifically, toner particles having a core-shell structure include firstly binder resin fine particles for core particles. The core particles are prepared by agglomerating (and fusing) the colorant fine particles, and then the binder resin fine particles for the shell layer are added to the core particle dispersion to bind the shell layer to the surface of the core particles. It can be obtained by agglomerating and fusing the fine resin particles to form a shell layer covering the surface of the core particles. Also in the case of toner particles having a core-shell structure, regarding the SP value of the binder resin (and each monomer forming the binder resin) of the color toner and the special color toner of the present invention, “(3- 1) SP value measurement method (Fedors method, etc.) "calculates the SP value of the binder resin of the core particles and the shell layer (and each monomer that forms these binder resins) in advance. After confirming that the formulas (1) to (3), preferably the formulas (1) and (4) to (5) are satisfied, the color toner is applied to the emulsion association method (emulsion aggregation method) described below. In addition, the binder resin for the core particles and the shell layer of the special color toner (further, each monomer forming these binder resins) may be used.

  When a toner is produced by an emulsion association method (emulsion aggregation method), the toner production method according to a preferred embodiment is a step of preparing a crystalline polyester resin fine particle dispersion, an amorphous resin fine particle dispersion, and a colorant dispersion. (Hereinafter also referred to as a preparation step) (a) and a step of mixing and aggregating and fusing a crystalline polyester resin dispersion, an amorphous resin dispersion and a colorant dispersion (hereinafter referred to as agglomeration and fusing steps) (B). Hereinafter, each process is explained in full detail.

(A) Preparation Step In more detail, the step (a) includes a crystalline polyester resin fine particle dispersion preparation step, an amorphous resin fine particle dispersion preparation step, and a colorant dispersion preparation step described below. And a release agent dispersion preparation step. As shown in the examples, since it is not essential to use a crystalline polyester resin as the binder resin, the crystalline polyester resin fine particle dispersion preparation step is optional and may be performed as necessary. That is, the preparation step (a) of the present invention only needs to include an amorphous resin fine particle dispersion preparation step and a colorant dispersion preparation step.

(A1) Crystalline polyester resin fine particle dispersion preparation step / Amorphous resin fine particle dispersion preparation step In the crystalline polyester resin fine particle dispersion preparation step, the crystalline polyester resin constituting the toner particles is synthesized, and this crystalline polyester is prepared. This is a step of preparing a dispersion of crystalline polyester resin fine particles by dispersing a resin in a fine particle form in an aqueous medium. In the step of preparing the amorphous resin fine particle dispersion, an amorphous resin constituting the toner particles, preferably an amorphous polyester resin, is synthesized, and the amorphous resin is dispersed in a fine particle form in an aqueous medium. This is a step of preparing a dispersion of amorphous resin fine particles.

  As a method of dispersing the crystalline polyester resin / amorphous resin in the aqueous medium, an oil phase liquid is prepared by dissolving or dispersing the resin in an organic solvent (solvent), and the oil phase liquid is phase-inverted and emulsified. For example, a method of dispersing the organic solvent in an aqueous medium to form oil droplets in a state of being controlled to have a desired particle diameter, and then removing the organic solvent.

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

  The amount of the organic solvent (solvent) used (when two or more types are used, the total amount used) is usually 1 to 300 parts by weight, preferably 10 to 200 parts by weight, more preferably 25 to 100 parts by weight of the resin. -100 mass parts. Such a range is preferable in that a dispersion of resin fine particles having a uniform particle size distribution can be obtained.

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

  The amount of the aqueous medium used is preferably 50 to 2,000 parts by mass and more preferably 100 to 1,000 parts by mass with respect to 100 parts by mass of the oil phase liquid. By making the usage-amount of an aqueous medium into said range, an oil phase liquid can be emulsified and dispersed to a desired particle size in an aqueous medium. The aqueous medium used here refers to a medium comprising 50 to 100% by mass of water and 0 to 50% by mass of a water-soluble organic solvent. Examples of the water-soluble organic solvent include methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, and tetrahydrofuran, and an alcohol-based organic solvent that does not dissolve the crystalline polyester resin / amorphous resin (resin fine particles) is used. It is preferable. In addition, amine or ammonia may be dissolved in the aqueous medium as necessary.

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

  Examples of the dispersion stabilizer include inorganic compounds such as tricalcium phosphate, calcium carbonate, titanium oxide, colloidal silica, and hydroxyapatite. Since it is necessary to remove the dispersion stabilizer from the toner base particles obtained, it is preferable to use those that are soluble in acids and alkalis such as tricalcium phosphate. It is preferable to use a decomposable one.

  Surfactants include alkylbenzene sulfonate, α-olefin sulfonate, phosphate ester, polyoxyethylene lauryl ether sodium sulfate, sodium alkyldiphenyl ether disulfonate, alkylamine salts, amino alcohol fatty acids Derivatives, polyamine fatty acid derivatives, amine salt types such as imidazoline, quaternary ammonium salt types such as alkyltrimethylammonium salt, dialkyldimethylammonium salt, alkyldimethylbenzylammonium salt, pyridinium salt, alkylisoquinolinium salt, benzethonium chloride Cationic surfactants, nonionic surfactants such as fatty acid amide derivatives, polyhydric alcohol derivatives, alanine, dodecyl di (aminoethyl) glycine, di (octyl) And amphoteric surfactants such as minoethyl) glycine and N-alkyl-N, N-dimethylammonium betaine. Anionic surfactants and cationic surfactants having a fluoroalkyl group can also be used. .

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

  The removal of the organic solvent after the formation of the oil droplets is performed by gradually heating the whole dispersion liquid in a state where the crystalline polyester resin fine particles / amorphous resin fine particles are dispersed in the aqueous medium while maintaining a constant temperature. After giving strong stirring in the area, it can be carried out by an operation such as desolvation. Alternatively, it can be removed while reducing the pressure using an apparatus such as an evaporator.

  The particle diameter of the crystalline polyester resin fine particles (oil droplets) or the amorphous resin fine particles (oil droplets) in the crystalline polyester resin fine particle dispersion or amorphous resin fine particle dispersion prepared in this way is the volume average particle size. The thickness is preferably 60 to 1000 nm, and more preferably 80 to 500 nm. Such a range is preferable in terms of stable toner production. In addition, the volume average particle diameter of the resin fine particles (oil droplets) (resin particles) is measured with a laser diffraction / scattering particle size distribution measuring device (Microtrac particle size distribution measuring device “UPA-150” (manufactured by Nikkiso Co., Ltd.)). Can be measured. The volume average particle diameter of the fine particles (oil droplets) can be controlled by the magnitude of mechanical energy during emulsification dispersion.

  In addition, the content of crystalline polyester resin fine particles or amorphous resin (especially amorphous polyester resin) fine particles in the crystalline polyester resin fine particle dispersion or amorphous resin (especially amorphous polyester resin) fine particle dispersion (solid) Is preferably in the range of 10 to 50% by mass, more preferably in the range of 15 to 40% by mass with respect to 100% by mass of the dispersion. Within such a range, the spread of the particle size distribution can be suppressed and the toner characteristics can be improved.

(A2) Colorant fine particle dispersion preparation step In this colorant fine particle dispersion preparation step, color toner (YMCK, etc.) and special color toner (white, metallic toner, etc. other than transparent toner) are desired as toner particles. This is an essential step, in which a colorant (pigment) is dispersed in the form of fine particles in an aqueous medium to prepare a dispersion of colorant fine particles.

  The said aqueous medium is as having demonstrated above, The thing similar to the aqueous medium used for dispersion | distribution of the crystalline polyester resin / amorphous resin of the said (a1) process can be used. In this aqueous medium, a surfactant or resin fine particles may be added for the purpose of improving dispersion stability. The surfactant and resin fine particles are also as described in the step (a1).

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

  The volume average particle diameter of the colorant fine particles is preferably 10 to 300 nm, and more preferably 100 to 250 nm. Such a range is preferable in that high color reproducibility can be obtained.

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

(A3) Release Agent Fine Particle Dispersion Preparation Step This release agent fine particle dispersion preparation step is a step that is performed as necessary when toner particles containing a release agent are desired. Is a step of dispersing a release agent fine particle dispersion in an aqueous medium in the form of fine particles.

  The said aqueous medium is as having demonstrated above, The thing similar to the aqueous medium used for dispersion | distribution of the crystalline polyester resin / amorphous resin of the said (a1) process can be used. In this aqueous medium, a surfactant or resin fine particles may be added for the purpose of improving dispersion stability. The surfactant and resin fine particles are also as described in the step (a1).

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

  In dispersing the release agent, heating may be performed as necessary. The heating temperature is preferably in the range of the melting point of the release agent ± 20 ° C. from the viewpoint of improving dispersibility.

  The volume average particle size of the release agent fine particles is preferably 10 to 300 nm. Within such a range, it is preferable in that good fixability can be obtained.

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

(B) Aggregation / fusion process This aggregation / fusion process is carried out by dispersing the crystalline polyester resin fine particle dispersion, the amorphous resin fine particle dispersion, and the colorant fine particle dispersion, and if necessary, the release agent fine particle dispersion. Add and mix other components such as liquid, slowly agglomerate while balancing the repulsive force of the fine particle surface by pH adjustment and the agglomeration force by the addition of an aggregating agent made of electrolyte, and the average particle size and particle size distribution In this process, toner particles are formed by performing association while controlling the shape and simultaneously controlling the shape by fusing the fine particles by heating and stirring. This agglomeration / fusion process can also be performed using mechanical energy or heating means as required. As shown in the Examples, the crystalline polyester resin fine particle dispersion is an optional component and may be added as necessary. That is, in the aggregation / fusion step (b) of the present invention, at least the amorphous resin fine particle dispersion and the colorant dispersion may be added and mixed, and the subsequent aggregation and fusion may be performed.

(B1) Aggregation step In the aggregation step, first, the obtained dispersions are mixed to form a mixed solution, which is heated and aggregated at a temperature not higher than the glass transition temperature of the amorphous resin to form aggregated particles. Aggregated particles are formed by acidifying the pH of the mixed solution with stirring. As pH, the range of 2.0-7.0 is desirable and the range of 2.0-5.0 is more desirable. Such a range is preferable in that agglomeration with a sharp particle size distribution is possible. In order to adjust the pH, for example, hydrochloric acid, sulfuric acid, nitric acid, bicarbonate, ammonia, caustic potash, caustic soda, sodium carbonate, potassium carbonate and the like can be used. At this time, it is also effective to use a flocculant.

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

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

  When the agglomerated particles have reached a desired particle size, the toner (core-shell particles) having a structure in which the surface of the core agglomerated particles is coated with the amorphous resin is added by adding amorphous fine particles. Can do. In the case of additional addition, a flocculant may be added or pH adjustment may be performed before additional addition. In the case where the core-shell particles are not formed, the following aggregation stopping step may be performed when the aggregated particles before the operation becomes a desired particle size.

  During the aggregation, it is preferable to heat and raise the temperature. At this time, if the temperature becomes higher than the fusing temperature due to heating and temperature rise, the fusing process also proceeds at the same time. The heating rate is preferably 0.1 to 5 ° C./min. Such a range is preferable in that agglomeration with a sharp particle size distribution is possible. Moreover, it is preferable to perform heating temperature (peak temperature) in the range of 40-100 degreeC. Such a range is preferable in that agglomeration with a sharp particle size distribution is possible.

(B2) Aggregation stopping step When the aggregated particles are measured with, for example, a Coulter counter and the desired average particle diameter is reached, the particle size growth (aggregation) of various fine particles in the reaction system is stopped (hereinafter, referred to as “aggregation particles”). Also referred to as aggregation stop step). Stopping the particle size growth (aggregation) is a base that can be adjusted in the direction away from the pH environment where the aggregating action of the fine particles in the agglomeration process is promoted in order to suppress the aggregating action of the fine particles in the reaction system. This is done by adding an aggregation terminator comprising a compound. The desired average particle size of the aggregated particles is not particularly limited, but the average particle size is preferably about 4.5 to 7.0 μm. Such a range is preferable in that a high-quality image can be obtained.

  In this aggregation stopping step, it is preferable to adjust the pH of the reaction system to 5.0 to 9.0. Such a range is preferable in that aggregation can be stopped immediately at a desired particle size.

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

(B3) Fusing Step After the fusing step (b2) or simultaneously with the aggregating step (b1), the fusing step is performed by heating the reaction system to a desired fusing temperature, thereby This is a step of forming the fused particles by fusing the constituent fine particles to fuse the aggregated particles.

  The fusing temperature in this fusing step is preferably equal to or higher than the melting point of the crystalline polyester resin, and the fusing temperature is preferably 0 to 20 ° C. higher than the melting point of the crystalline polyester resin. The heating time may be as long as fusion is performed, and may be performed for about 0.5 to 10 hours. Preferably, as shown in the examples, a desired shape factor (for example, a flow type particle image analyzer (for example, a flow type particle image analyzer FPIA-2000 manufactured by Hosokawa Micron Co., Ltd.) or the like is used. , About 0.96).

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

  The addition ratio (mass ratio) of the amorphous resin fine particles / crystalline polyester resin fine particles in the aggregation / fusion step is preferably 1 to 100. Within such a range, the obtained toner has excellent heat-resistant storage properties and excellent low-temperature fixability. This requirement can be applied to the case where the agglomeration / fusion process is performed using amorphous resin fine particles and crystalline polyester resin fine particles in combination.

  When other internal additives are introduced into the toner particles, an internal additive fine particle dispersion consisting only of the internal additive is prepared before the aggregation / fusion process, and crystals are formed in the aggregation / fusion process. A method of mixing the dispersion of the internal additive fine particles together with the dispersion of the fine polyester resin particles, the dispersion of the amorphous resin fine particles, and the colorant dispersion is preferable.

  Cool after fusion to obtain fused particles. The cooling rate is preferably 2 to 20 ° C./min. Such a range is preferable in that the toner surface after cooling is smooth.

  When a toner is obtained by an emulsion aggregation method, the volume median diameter of the toner can be controlled by controlling the particle size growth of the aggregated particles (aggregation conditions).

  When a toner is obtained by an emulsion association method (emulsion aggregation method), it is preferable to have a shape factor (circularity) control step after the aggregation / fusion step. That is, in a preferred embodiment, a method for producing a color toner and a special color toner includes a step of preparing a crystalline polyester resin fine particle dispersion, an amorphous resin fine particle dispersion, and a colorant dispersion (hereinafter referred to as a preparation step). (A) and a step of aggregating and fusing the crystalline polyester resin dispersion, the amorphous resin dispersion and the colorant dispersion (hereinafter also referred to as agglomeration and fusing step) (b) and And a shape factor (circularity) control step (c) for controlling the shape factor (circularity) of the toner.

  Specifically, the shape factor (circularity) control process includes a heating process for heating the particles obtained in the aggregation / fusion process. The shape factor (circularity) can be controlled by the heating temperature and holding time. By increasing the heating temperature or extending the holding time, the shape factor (circularity) can be made close to 1. However, since reaggregation of the toners occurs, it is not preferable to raise the heating temperature excessively. For the same reason, it is not preferable to make the holding time too long.

  The heating temperature in the shape factor (circularity) control process is preferably 70 to 95 ° C, more preferably 70 to 90 ° C, from the viewpoint of bringing the shape factor (circularity) close to 1. The holding time at the heating temperature is not particularly limited, and may be performed until the shape factor (circularity) reaches a target value (a value close to 1) as shown in the examples. The shape factor (circularity) is controlled by measuring the circularity of the particle diameter with a volume median diameter of 2 μm or more with a shape factor (circularity) measuring device during heating to determine whether the desired circularity is obtained. Control is possible by appropriately determining the above. The volume median diameter is a volume-based median diameter (volume-based median diameter) measured by a precision particle size distribution measuring apparatus (for example, “Multisizer 3” manufactured by Beckman Coulter, Inc.) employing the Coulter principle. It is.

  Furthermore, the toner production method in the emulsion association method (emulsion aggregation method) may include (d) a filtration / washing step, (e) a drying step, and (f) an external additive addition step.

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

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

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

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

(10) Developer The toner as described above contains, for example, a magnetic material and is used as a one-component magnetic toner. When the toner is mixed with a so-called carrier and used as a two-component developer, a non-magnetic toner is used alone. Any of them can be used preferably.

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

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

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

(11) Image Forming Method The image forming method of the present invention includes a toner that forms a secondary color and a toner that does not form a secondary color (used in an image forming apparatus that forms a color toner image by a plurality of developing machines. The image forming method using the toner set, wherein the toner having the maximum solubility parameter value (SP value: (cal / cm ³ ) ^1/2 ) of the binder resin of the toner that forms the secondary color is the first. The first toner, the minimum toner as the second toner, and the toner that does not produce the secondary color as the third toner, the solubility parameter values of the binder resin of each of the first to third toners (SP value: (cal / cm ³⁾ ) ^1/2 ) is SP (1), SP (2), SP (3), the above formulas (1) to (3), preferably the formulas (1) and (4) to (5) It is characterized by satisfying.

  In the image forming method of the present invention, an image forming layer A obtained using a special color toner and an image forming layer B adjacent to the image forming layer A and obtained using a color toner different from the special color toner are used as media. An image is formed by fixing on a (recording medium). In this case, after fixing the image forming layer A obtained by transferring the special color toner onto the recording medium, a method for fixing the image forming layer B obtained by transferring the color toner onto the recording medium (under the full color image) Form in which a special color toner layer is formed), and a method of fixing the image forming layer A obtained by transferring the special color toner onto the recording medium after fixing the image forming layer B obtained by transferring the color toner onto the recording medium (A form in which a special color toner layer is formed on the upper layer of a full color image), an image forming layer A obtained by transferring the special color toner onto the recording medium and an image forming layer B obtained by transferring the color toner onto the recording medium. And a fixing method (a form in which a special color toner layer is formed on the upper layer or the lower layer of a full-color image). However, since the effect of the present invention is further obtained and the image formation is fast, the image forming layer An image forming layer B is preferably formed an image by fixing in bulk.

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

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

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

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

(10-1) Recording medium The recording medium (also referred to as media, recording material, recording paper, recording paper, etc.) may be a commonly used one, for example, formed by a known image forming method using an image forming apparatus or the like. There is no particular limitation as long as it retains a toner image. Examples of usable image supports include plain paper from thin paper to thick paper, high-quality paper, art paper, coated printing paper such as coated paper, commercially available Japanese paper and postcard paper, OHP Plastic film, cloth, soft transparent film, synthetic paper such as YUPO paper, and the like. In the image forming method of the present invention, in particular, when outputting to a special recording medium such as colored paper, black paper, aluminum vapor-deposited paper or transparent film, even if a special color toner layer is formed on the upper layer or lower layer of the full-color image, The visibility of the toner is improved, the reproducibility of the secondary color of the color image is good, and it is possible to form a high-quality and high-quality image without color blurring and image peeling, and the added value as an image It is excellent in that it can be increased.

(11) Image Forming Apparatus The present invention further provides an image forming apparatus capable of forming a color toner image from the toner set described in the first embodiment using a plurality of developing machines.

  As described above, according to the present invention, the SP value of the binder resin of the color toner and the binder resin of the color toner and the special color toner is controlled within an appropriate numerical range (the above formulas (1) to (3)). Therefore, the configuration of the image forming apparatus itself is a known image forming apparatus in which a toner set composed of color toner and special color toner satisfying the relations of the above formulas (1) to (3) is installed. That's fine. As an image forming apparatus equipped with a toner set composed of color toner and special color toner, for example, an apparatus disclosed in Japanese Patent Application Laid-Open No. 2006-220694 and the like can be cited.

  Hereinafter, an image forming method using a toner set composed of a color toner and a special color toner satisfying the relationship of the above formulas (1) to (3), which is used in an image forming apparatus for forming a color toner image by a plurality of developing machines. This will be described with reference to the drawings.

  FIG. 1 is a schematic cross-sectional view showing an example of a color image forming apparatus according to an image forming method using the toner set of the present invention. FIG. 1 shows an example in which four types of YMCK are used as color toners and white toner (W) is used as a special color toner. In addition to such white toner, metallic toner (ME), transparent toner can be used depending on the purpose. (CL) can be used alone or in combination.

  First, an outline of an image forming apparatus for color electrophotography equipped with a detection sensor and a secondary transfer device will be described.

  The image forming apparatus GS is called a tandem type color image forming apparatus, and is a yellow toner, a magenta, a cyan, and a black color toner image along the moving direction of the intermediate transfer member 36, and a white toner that is a kind of special color toner. An image forming unit for forming an image is arranged, and a color toner image and a white toner image formed on the image carrier of each image forming unit are superimposed on the intermediate transfer member, and then superimposed on the image support member. Batch transfer.

  In FIG. 1, a document image placed on an image reading device SC disposed at a position occupying the upper portion of the image forming device GS is scanned and exposed by an optical system, read into a line image sensor CCD, and line image sensor CCD. The analog signal photoelectrically converted by the image processing unit performs analog processing, A / D conversion, shading correction, image compression processing, and the like in the image processing unit, and then sends an image data signal to the exposure optical system 33 as image writing means. .

  The intermediate transfer member 36 includes a drum type and an endless belt type, both of which have the same function. In the following description, the intermediate transfer member is an endless belt-like intermediate transfer member 36. I will point to.

  Further, in FIG. 1, five sets are formed on the peripheral portion of the intermediate transfer member 36 for image formation for each color of yellow (Y), magenta (M), cyan (C), black (K), and white (W). The process unit 100 is provided. The process unit 100 is arranged in a vertical direction along the intermediate transfer body 36 as a means for forming a color toner image and a white toner image along the intermediate transfer body 36 with respect to the rotation direction of the intermediate transfer body 36 in the vertical direction indicated by arrows in the drawing. , M, C, K, W.

  The five sets of process units 100 all have a common structure, and each includes a photosensitive drum 31, a charger 32 as a charging unit, an exposure optical system 33 as an image writing unit, and a developing device (developer). 34 and a photoconductor cleaning device 190 as an image carrier cleaning means.

  The photosensitive drum 31 has a photosensitive layer having a layer thickness (film thickness) of about 20 to 40 μm formed on the outer periphery of a cylindrical substrate formed of a metallic member such as aluminum having an outer diameter of about 40 to 100 mm. Is. The photosensitive drum 31 is rotated in the direction of the arrow in the direction of the arrow with the substrate grounded by power from a drive source (not shown), for example, at a linear velocity of about 80 to 280 mm / s, preferably 220 mm / s.

  Around the photosensitive drum 31, there is an image forming unit including a charger 32 as a charging unit, an exposure optical system 33 as an image writing unit, and a developing device (developing machine) 34 as indicated by an arrow in the figure. It arrange | positions with respect to the rotation direction of the photoreceptor drum 31 shown.

  The charger 32 as a charging unit is attached in close proximity to the photosensitive drum 31 in a direction parallel to the rotation axis of the photosensitive drum 31. The charger 32 includes a discharge wire as a corona discharge electrode that applies a predetermined potential to the photosensitive layer of the photosensitive drum 31, and performs a charging action (negative charging in the present embodiment) by corona discharge having the same polarity as the toner. A uniform potential is applied to the photosensitive drum 31.

  The exposure optical system 33 as image writing means rotates and scans laser light emitted from a semiconductor laser (LD) light source (not shown) in the main scanning direction by a rotating polygon mirror (no symbol), and an fθ lens (no symbol). ), Exposure on the photosensitive drum 31 by an electric signal corresponding to the image signal (image writing) through a reflecting mirror (not shown), and the like. Form an image.

  A developing device 34 as a developing unit is provided for each color of yellow (Y), magenta (M), cyan (C), black (K), and white (W) charged to the same polarity as the charging polarity of the photosensitive drum 31. A developing roller 34a, which is a developer carrier formed of a cylindrical nonmagnetic stainless steel or aluminum material having a thickness of 0.5 to 1 mm and an outer diameter of 15 to 25 mm, for example, is provided. The developing roller 34a is kept in contact with the photosensitive drum 31 with a predetermined roller (not shown) with a predetermined gap, for example, 100 to 1000 μm, and rotates in the same direction as the rotational direction of the photosensitive drum 31. At the time of development, a photoconductive drum is applied to the developing roller 34a by applying to the developing roller 34a a DC voltage having the same polarity as the toner (negative polarity in this embodiment) or a developing bias voltage that superimposes an AC voltage on the DC voltage. The reversal development is performed on the exposed portion on 31.

The intermediate transfer member 36 has a volume resistivity of about 1.0 × 10 ^{7 to} 1.0 × 10 ⁹ Ω · cm, and a surface resistivity of about 1.0 × 10 ^{10 to} 1.0 × 10 ¹² Ω / □. A semiconductive endless (seamless) resin belt is used. As the resin belt, a semiconductive material having a thickness of 0.05 to 0.5 mm in which a conductive material is dispersed in engineering plastics such as modified polyimide, thermosetting polyimide, ethylene tetrafluoroethylene copolymer, polyvinylidene fluoride, and nylon alloy. A resin film can be used. In addition to this, a semiconductive rubber belt having a thickness of 0.5 to 2.0 mm in which a conductive material is dispersed in silicone rubber, urethane rubber, or the like can also be used as the intermediate transfer member 36. The intermediate transfer member 36 is wound around a plurality of roller members including a tension roller 36a and a backup roller 36B facing the secondary transfer member, and is supported so as to be rotatable in the vertical direction.

  The primary transfer roller 37 as a first transfer unit for each color is made of a roller-like conductive member using foamed rubber such as silicone or urethane, for example, and the photosensitive drum 31 for each color with the intermediate transfer body 36 interposed therebetween. The transfer area is formed between the photosensitive drum 31 and the back surface of the intermediate transfer body 36 by pressing the back surface thereof. A DC constant current having a polarity opposite to that of the toner (positive polarity in the present embodiment) is applied to the primary transfer roller 37 by constant current control, and the toner image on the photosensitive drum 31 is formed by a transfer electric field formed in the transfer area. Transferred onto the intermediate transfer member 36.

  The toner image transferred onto the intermediate transfer member 36 is transferred to the image support P. A detection sensor 38 for measuring the density of the patch image toner is provided on the periphery of the intermediate transfer member 36.

  In order to clean the residual toner on the intermediate transfer member 36, a cleaning device 190A is provided.

  Further, a secondary transfer device 70 is provided to clean the patch image toner on the secondary transfer member 37A.

  Next, an image forming method (image forming process or process) will be described.

  The yellow (Y) photosensitive drum 31 is rotated in the direction indicated by the arrow in the figure by starting the photosensitive drum drive motor (not shown) upon starting image recording, and the Y charger 32 supplies a potential to the Y photosensitive drum 31. Is granted. After the Y photosensitive drum 31 is applied with a potential, the Y exposure optical system 33 performs exposure (image writing) with an electrical signal corresponding to the first color signal, that is, the Y image data. An electrostatic latent image corresponding to a yellow (Y) image is formed on the body drum 31. The latent image is reversely developed by the Y developing device 34, and a toner image made of yellow (Y) toner is formed on the Y photosensitive drum 31. The Y toner image formed on the Y photosensitive drum 31 is transferred onto the intermediate transfer member 36 by the primary transfer roller 7 as a primary transfer unit.

  Next, a potential is applied to the M photosensitive drum 31 by the magenta (M) charger 32. After the M photoconductor drum 31 is applied with a potential, the M exposure optical system 33 performs exposure (image writing) with an electrical signal corresponding to the first color signal, that is, the M image data. An electrostatic latent image corresponding to the magenta (M) image is formed on the body drum 31. The latent image is reversely developed by the M developing device 34, and a toner image made of magenta (M) toner is formed on the M photosensitive drum 31. The M toner image formed on the M photoconductor drum 31 is superimposed on the Y toner image and transferred onto the intermediate transfer member 36 by a primary transfer roller 37 as a primary transfer unit.

  By a similar process, a toner image made of cyan (C) toner formed on the cyan (C) photosensitive drum 31 and a black (K) toner image formed on the black (K) photosensitive drum 31 are processed. A toner image made of toner is sequentially superimposed on the intermediate transfer member 36, and a superimposed color toner image made of Y, M, C, and K toners is formed on the peripheral surface of the intermediate transfer member 36. .

  Next, the white (W) photosensitive drum 31 is rotated in the direction indicated by the arrow in the drawing, and a potential is applied to the W photosensitive drum 31 by the W charger 32. After the W photosensitive drum 31 is applied with a potential, the W exposure optical system 33 performs exposure (image writing) with an electrical signal corresponding to the first color signal, that is, the W image data. An electrostatic latent image corresponding to a white (W) image is formed on the body drum 31. The latent image is reversely developed by the W developing device 34, and a toner image made of white (W) toner is formed on the W photosensitive drum 31. The W toner image formed on the W photosensitive drum 31 is transferred onto the intermediate transfer member 36 by the primary transfer roller 7 as a primary transfer unit. As a result, a superimposed color toner image composed of Y, M, C, and K toners is formed on the peripheral surface of the intermediate transfer member 36, and a white (special color) toner image composed of W toner is formed on the color toner image. It is formed. In the example of FIG. 1, the toner image made of white (W) toner is formed in the lower layer of the color image formed by the combination of the color toners with sufficient color development only with the full color toner. By forming an image with color toner on the top, it is formed over the entire image forming area of the image support P (recording medium) so that the visibility of the color toner is improved and the added value as an image can be increased. The

  The toner remaining on the peripheral surface of each photoreceptor drum 31 after the transfer is cleaned by the photoreceptor cleaning device 190.

  On the other hand, the image support P as recording paper accommodated in the paper feed cassettes 50A, 50B, and 50C is fed by the feed roller 51 and the paper feed roller 52A provided in the paper feed cassettes 50A, 50B, and 50C, respectively. Secondary transfer as a secondary transfer unit that is transported on the transport path 52 by transport rollers 52B, 52C, and 52D, and is applied with a voltage having a polarity opposite to that of the toner (positive polarity in the present embodiment) through the registration roller 53. A superposed color toner image (color image) formed on the intermediate transfer member 36 in the transfer area of the secondary transfer member 37A conveyed to the member 37A and white (special color) on the color toner image (color image). ) The toner images are transferred onto the image support P at once. Thereby, an image is formed with the color toner on the white toner layer.

  The image support P on which the color image has been transferred onto the white toner layer (solid white base layer) is heated and pressed at the nip formed by the heating roller 47a and the pressure belt 47b of the fixing device 47. The paper is fixed, sandwiched between paper discharge rollers 54, and placed on a paper discharge tray 55 outside the apparatus.

  After the white toner layer (solid white base layer) and the color image are transferred onto the image support P by the secondary transfer member 37A as the secondary transfer means, the intermediate transfer body 36 obtained by separating the curvature of the image support P is obtained. The residual toner on the upper side is removed by the intermediate transfer member cleaning device 190A.

  Further, the patch image toner on the secondary transfer member 37 </ b> A is cleaned by the cleaning blade 71 of the secondary transfer device 70.

  As described above, in the image forming method using the image forming apparatus (developer) containing the toner set composed of the color toner and the special color toner (white toner) of the present invention, the binder resin of the color toner, and the color toner By controlling the SP value of the binder resin of white and white (special color) toner within an appropriate numerical range, white toner (special color) can be used for the (upper layer) or lower layer of a full-color image even when using a small-diameter toner required for high image quality Even if the toner layer is formed, it is possible to form a high-quality, high-value-added image with good color image secondary color reproducibility and no “color blur” or “image peeling”. .

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

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

<Measurement and calculation method>
1. Average particle diameter of toner Measurement and calculation using a device in which a computer system (manufactured by Beckman Coulter) equipped with data processing software “Software V3.51” is connected to Coulter Counter Multisizer 3 (manufactured by Beckman Coulter) .

  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) in a sample stand with a pipette until the display density of the measuring instrument becomes 5% to 10%. By setting this concentration range, a reproducible measurement value can be obtained. In the measuring machine, the measurement particle count is set to 25000, the aperture diameter is set to 100 μm, the frequency value is calculated by dividing the measurement range of 2.0 to 60 μm into 256, and the volume integrated fraction is 50 % Particle diameter is defined as the volume median diameter (volume-based median diameter (volume D50% diameter)).

  For the average particle diameter of the toner, a value obtained by rounding off the third decimal place to the second decimal place is adopted.

2. Toner shape factor The toner shape factor is a value measured using a flow particle image analyzer (manufactured by Hosokawa Micron Corporation, flow particle image analyzer FPIA-2000). The toner before the external addition treatment is purely dispersed, and the shape factor is measured with a flow particle image analyzer FPIA-2000. Specifically, after blending the sample with a solution of a surfactant in a commercially available dedicated sheath liquid, dispersing for 1 minute by ultrasonic dispersion, using a flow particle image analyzer FPIA-2000, Measurement conditions In the HPF (high magnification imaging) mode, measurement is performed at an appropriate density of 3000 to 10,000 HPF detections. Within this range, reproducible identical measurement values can be obtained. The shape factor defined by the following equation was measured.

  The shape factor is a value calculated by adding the shape factor (circularity) of each particle and dividing by the total number of particles.

  As the toner shape factor, a value obtained by rounding off the fourth decimal place to the third decimal place is adopted.

3. Glass transition temperature (Tg) of amorphous polyester resin
The glass transition temperature (Tg) of the amorphous polyester resin was obtained using a differential scanning calorimeter (manufactured by Shimadzu Corporation: DSC-60A) in accordance with ASTM D3418. The temperature correction of the detection part of this apparatus (DSC-60A) was performed using the melting point of indium and zinc, and the heat of fusion of indium was used to correct the amount of heat. For the sample, an aluminum pan was used, an empty pan was set as a control, the temperature was increased at a temperature increase rate of 10 ° C./min, held at 200 ° C. for 5 minutes, and liquid nitrogen was used from 200 ° C. to 0 ° C. The temperature was lowered at 10 ° C./min, held at 0 ° C. for 5 minutes, and again heated from 0 ° C. to 200 ° C. at 10 ° C./min. Analysis was performed from the endothermic curve during the second temperature increase, and the onset temperature was defined as the glass transition temperature (Tg) of the amorphous polyester resin.

4). Volume average particle diameter of resin particles such as binder resin, colorant particles, release agent (particles), etc. Volume average particle diameter of resin particles such as binder resin, colorant particles, release agent (particles), etc. Measurement was performed with a laser diffraction / scattering particle size distribution measuring device (Microtrac particle size distribution measuring device “UPA-150” (manufactured by Nikkiso Co., Ltd.)).

(Synthesis of binder resin 1)
Terephthalic acid 50.7 parts by weight, trimellitic acid 5.1 parts by weight, dodecanedioic acid 33.8 parts by weight, dodecenyl succinic anhydride 135.1 parts by weight, bisphenol A propylene oxide (BPA-PO) 6 mol adduct 405. 4 parts by mass was put into a reaction vessel equipped with a stirrer, a thermometer, a cooling tube, and a nitrogen gas introduction tube, and after the inside of the reaction vessel was replaced with dry nitrogen gas, 0.1 parts by mass of titanium tetrabutoxide was added, and nitrogen was added. The polymerization reaction was carried out for 8 hours with stirring at 180 ° C. in a gas stream. Further, 0.2 parts by mass of titanium tetrabutoxide was added, the temperature was raised to 220 ° C., and the polymerization reaction was carried out for 6 hours while stirring. Then, the reaction vessel was depressurized to 10 mmHg, reacted under reduced pressure, and bound. As the resin, a pale yellow transparent amorphous polyester resin (binder resin 1) was obtained. The glass transition temperature (Tg) determined by a differential scanning calorimeter (DSC) was 49 ° C., and the weight average molecular weight (Mw) determined by a gel permeation chromatograph analyzer (GPC) was 28000. The SP value of the binder resin 1 calculated by the Fedors method was 9.91. The unit of the SP value is (cal / cm ³ ) ^1/2 . The units of SP values shown in Table 1 below are the same, but these units are omitted.

(Synthesis of binder resins 2-7)
Hereinafter, the monomer (monomer) put in the reaction vessel and the content thereof are changed to the monomer (monomer) and the content thereof shown in Table 1 below, and the glass transition temperature (Tg) is in the range of 50 ° C. ± 1 ° C. Amorphous polyester resins (binder resins 2 to 7) were respectively synthesized as the binder resin in the same manner as the binder resin 1 except that the molecular weight was controlled by the reaction time. BPA-PO (2 mol adduct) in Table 1 is a bisphenol A propylene oxide 2 mol adduct. BPA-PO (6 mol adduct) is a bisphenol A propylene oxide 6 mol adduct. Further, BPA-EO (2 mol adduct) is a bisphenol A ethylene oxide 2 mol adduct. (Here, the number of moles of PO and EO in BPA is the number of moles obtained by adding PO / EO at both ends. The same applies hereinafter.)

(Preparation of resin dispersion 1)
After 200 parts by mass of binder resin 1 is dissolved in 200 parts by mass of ethyl acetate, the mixture is mixed with an aqueous solution in which sodium polyoxyethylene lauryl ether sulfate is dissolved in 800 parts by mass of ion-exchanged water so as to have a concentration of 1% by mass. Dispersion was performed using a sonic homogenizer. After removing ethyl acetate from this solution under reduced pressure, a resin dispersion 1 was prepared. The solid content concentration of resin dispersion 1 (content of resin fine particles 1) was adjusted to 20% by mass. The average particle diameter of binder resin 1 (resin fine particles 1) in resin dispersion 1 was 230 nm.

(Preparation of resin dispersion 2-7)
Resin dispersions 2 to 7 (solid content concentration adjusted to 20% by mass) are the same as the preparation of resin dispersion 1 except that binder resin 1 used is changed to binder resins 2 to 7 Prepared. The average particle diameter of the binder resins 1 to 7 (resin fine particles 1 to 7) in the obtained resin dispersions 1 to 7 is shown in Table 2 below.

(Preparation of cyan colorant dispersion)
As a cyan colorant (pigment), C.I. I. Pigment Blue 15: 3 50 parts by weight is added to a surfactant aqueous solution in which 1 part by weight of sodium alkyldiphenyl ether disulfonate is dissolved in 200 parts by weight of ion-exchanged water, and then dispersed using an ultrasonic homogenizer to obtain a cyan colorant dispersion. Was prepared. The solid content concentration (cyan colorant content) in the cyan colorant dispersion was adjusted to 20% by mass. The average particle size of the cyan colorant in the cyan colorant dispersion was 150 nm.

(Preparation of magenta colorant dispersion)
As a magenta colorant (pigment), C.I. I. Pigment Red 238 50 parts by mass is added to a surfactant aqueous solution in which 1 part by mass of sodium alkyldiphenyl ether disulfonate is dissolved in 200 parts by mass of ion-exchanged water, and then dispersed using an ultrasonic homogenizer to prepare a magenta colorant dispersion. did. The solid content concentration (magenta colorant content) in the magenta colorant dispersion was adjusted to 20% by mass. The average particle size of the magenta colorant in the magenta colorant dispersion was 150 nm.

(Preparation of yellow colorant dispersion)
As a yellow colorant (pigment), C.I. I. 50 parts by weight of Pigment Yellow 74 was added to a surfactant aqueous solution in which 1 part by weight of sodium alkyldiphenyl ether disulfonate was dissolved in 200 parts by weight of ion-exchanged water, and then dispersed using an ultrasonic homogenizer to prepare a yellow colorant dispersion. did. The solid content concentration (yellow colorant content) in the yellow colorant dispersion was adjusted to 20% by mass. The average particle size of the yellow colorant in the yellow colorant dispersion was 153 nm.

(Preparation of black colorant dispersion)
As a black colorant (pigment), 50 parts by mass of carbon black (Mogul-L) was added to a surfactant aqueous solution in which 1% by mass of sodium alkyldiphenyl ether disulfonate was dissolved in 200 parts by mass of ion-exchanged water, and then an ultrasonic homogenizer was used. Dispersion was performed to prepare a black colorant dispersion. The solid content concentration (the content of the black colorant) in the black colorant dispersion was adjusted to 20% by mass. The average particle diameter of the black colorant in the black colorant dispersion was 152 nm.

(Preparation of white colorant dispersion)
As a white colorant (pigment), 210 parts by mass of rutile titanium oxide (manufactured by Ishihara Sangyo Co., Ltd.) was added to a surfactant aqueous solution in which 1% by mass of sodium alkyldiphenyl ether disulfonate was dissolved in 480 parts by mass of ion-exchanged water. Dispersion was performed using an ultrasonic homogenizer to prepare a white colorant dispersion. The solid content concentration (white colorant content) in the white colorant dispersion was adjusted to 30% by mass. The average particle diameter of the white colorant in the white colorant dispersion was 200 nm.

(Preparation of metallic colorant dispersion)
As a metallic colorant (pigment), 210 parts by mass of an aluminum pigment (Showa Aluminum Powder Co., Ltd., 260EA, average particle size 10 μm) obtained by removing the solvent from a paste-like material, and 1% by mass of sodium alkyldiphenyl ether disulfonate are ion-exchanged. After charging into a surfactant aqueous solution dissolved in 480 parts by mass of water, dispersion was performed using an ultrasonic homogenizer to prepare a metallic colorant dispersion. The solid content concentration (the content of the metallic colorant) in the metallic colorant dispersion was adjusted to 30% by mass. The average particle diameter of the metallic colorant in the metallic colorant dispersion was 4 μm.

(Preparation of release agent dispersion)
As a mold release agent, 200 parts by mass of Fuchter-Tropsch wax (FNP-0090, melting point 89 ° C., manufactured by Nippon Seiki Co., Ltd.) was heated to 95 ° C. and melted. Furthermore, after throwing in the surfactant aqueous solution melt | dissolved in 800 mass parts of ion-exchange water added so that it might become 3 mass% of sodium alkyldiphenyl ether disulfonate, dispersion | distribution was performed using the ultrasonic homogenizer, and the mold release agent dispersion liquid was prepared. The solid content concentration (release agent content) in the release agent dispersion was adjusted to 20% by mass. The average particle diameter of the release agent in the release agent dispersion was 190 nm.

(Color toner synthesis)
Resin dispersion 1 875.2 parts by weight, release agent dispersion 85.0 parts by weight, cyan colorant dispersion 62 parts by weight, polyoxyethylene lauryl ether sodium sulfate 0.5 part by weight, stirrer, condenser, temperature The reaction vessel was equipped with a meter, and 0.1N hydrochloric acid was added with stirring to adjust the pH to 2.5. Next, after 0.4 parts by mass of a polyaluminum chloride aqueous solution (10 mass% aqueous solution in terms of AlCl ₃ ) was dropped over 10 minutes, the temperature was raised at a rate of 0.05 ° C./min with stirring, “Multisizer 3”. The particle size of the agglomerated particles was appropriately measured by (manufactured by Beckman Coulter). When the volume-based median diameter of the aggregated particles reached 5.6 μm, the temperature increase was stopped. Thereafter, the pH in the system was set to 8.5 with a 0.5N sodium hydroxide aqueous solution, and the particle size growth was stopped. Further, the internal temperature was raised to 85 ° C., and when “FPIA-2000” (manufactured by Sysmex) was used, when the average circularity (shape factor) reached 0.960, it was cooled to room temperature at a rate of 10 ° C./min. The reaction solution was repeatedly filtered and washed, and then dried to obtain a cyan toner which is a kind of color toner.

  By the above color toner synthesis method, a C1 toner having an average particle diameter of 5.60 μm and a shape factor of 0.965 was obtained as a cyan toner. Further, except that the colorant dispersion was changed, M1 toner as Magenta toner, Y1 toner as Yellow toner, and K1 toner as Black toner were prepared in the same manner as the color toner synthesis method described above. These average particle diameters and shape factors are as shown in Table 3 below. Further, each color toner (YMCK) was changed in the same manner as the color toner synthesis method except that the resin dispersion 1 was changed to the resin dispersion shown in Table 3 below and the colorant dispersion was appropriately changed. Produced. Their average particle diameter and shape factor are as shown in Table 3 below. In the color toner in Table 3, cyan toner is C (resin dispersion number) toner, magenta toner is M (resin dispersion number) toner, and yellow toner is Y (resin dispersion number). ) Toner and black toner was K (resin dispersion number) toner.

(Composition of special color toner)
Synthesis of white (W1) toner Resin dispersion 1 683.3 parts by weight, release agent dispersion 94.4 parts by weight, white (white) colorant dispersion 222.2 parts by weight, and polyoxyethylene lauryl ether sulfate 0.5 parts by mass of sodium was put into a reaction vessel equipped with a stirrer, a condenser, and a thermometer, and 0.1N hydrochloric acid was added with stirring to adjust the pH to 2.5. Next, after 0.4 parts by mass of a polyaluminum chloride aqueous solution (10 mass% aqueous solution in terms of AlCl ₃ ) was dropped over 10 minutes, the temperature was raised at a rate of 0.05 ° C./min with stirring, “Multisizer 3”. The particle size of the agglomerated particles was appropriately measured by (manufactured by Beckman Coulter). When the volume-based median diameter of the aggregated particles reached 5.6 μm, the temperature increase was stopped. Thereafter, the pH in the system was set to 8.5 with a 0.5N sodium hydroxide aqueous solution, and the particle size growth was stopped. Further, the internal temperature was raised to 85 ° C., and when “FPIA-2000” (manufactured by Sysmex) was used, when the average circularity (shape factor) reached 0.960, it was cooled to room temperature at a rate of 10 ° C./min. The reaction solution was repeatedly filtered and washed, and then dried to obtain a white toner which is a kind of special color toner.

  As a white toner, a W1 toner having an average particle size of 5.60 μm and a shape factor of 0.965 was obtained by the above-described special color toner synthesis method.

・ Synthesis of white (W2 to W7) toner and transparent (CL1, 7) toner Except for changing the resin dispersion and the colorant dispersion, each of the special color toners (white ( W2-W7) toner and transparent (CL1, 7) toner) were prepared. Their average particle diameter and shape factor are as shown in Table 4 below.

・ Synthesis of metallic (ME1, 7) toner For the synthesis of metallic toner, the resin dispersion and the colorant dispersion were changed, and when the volume-based median diameter of the aggregated particles reached 7.50 μm, the temperature was increased. “Stopped”, and further, “When the internal temperature is raised to 85 ° C. and“ FPIA-2000 ”(manufactured by Sysmex Corp.) is used, the average circularity (shape factor) becomes 0.950, 10 ° C./min. A special color toner (metallic (ME1, 7) toner) was produced in the same manner as in the special color toner synthesis method described above except that it was cooled to room temperature at a speed. Their average particle diameter and shape factor are as shown in Table 4 below.

  In the composition of the special color toner and the special color toner in Table 4, the white toner is W (resin dispersion number) toner, the metallic toner is ME (resin dispersion number) toner, and the transparent toner is CL. (Number of resin dispersion) Toner was used.

(Toner external processing)
With respect to 100 parts by mass of the obtained toner, 1.5 parts by mass of sol-gel silica having an average particle diameter of 100 nm hydrophobized with a hydrophobizing agent, and fumed with an average particle diameter of 20 nm hydrophobized with a hydrophobizing agent. 0.5 parts by mass of silica and 0.5 parts by mass of titania having an average particle diameter of 30 nm hydrophobized with a hydrophobizing agent are put in a mixer, mixed at a stirring speed of 25 m / s for 45 minutes, and evaluated (evaluation toner) ) Was prepared (referred to as external additive formulation 1). Further, a toner to be evaluated (evaluation toner) was prepared in the same manner as the external addition process of the toner described above except that the amount of the external additive to be added was changed as shown in Table 5 below (referred to as external additive formulation 2). .

Examples 1-19, Comparative Examples 1-12
The obtained evaluation toner was used as a developer prepared according to “Production of developer” below, and an evaluation toner set was formed by combining these developers as shown in Table 6 below. Specifically, a combination of color toner (four types of yellow, magenta, cyan, and black toner) and a special color toner (white, metallic, and transparent toner) described in Table 6 below was used. An image was formed using an evaluation toner set combined as shown in Table 6 below, and the secondary color reproducibility, color bleeding, and image peeling were evaluated. Further, the evaluation toner was evaluated by measuring the Si / C amount. The evaluation results are shown in Table 6 below.

(Development of developer)
For each toner, a ferrite carrier coated with an acrylic resin and having a volume average particle diameter of 35 μm was mixed so that the toner concentration was 6% by mass to prepare a developer.

(Image forming method and evaluation method for secondary color reproducibility evaluation)
Each developer (evaluation toner set) in which one of the color toner (four types of YMCK) prepared above and one of the special color toners (W, ME, CL) was combined as shown in Table 6 below was added 5 The developing machine is put into a remodeling machine for the bizhub Pro C6500, which is an image forming apparatus (four types of YMCK are converted to five types of YMCK + special color toner, see FIG. 1), and a transparent OHP sheet is used. A 1 cm square solid image of red (M + Y), blue (M + C), and green (C + Y) was prepared in the center of the lowermost special color toner layer of 5 cm square. The color of the solid image portion in each of the first formed image and the 10,000th formed image was measured by “Macbeth Color-Eye 7000”, and the color difference was calculated using the CMC (2: 1) color difference formula. If the color difference obtained by the CMC (2: 1) color difference formula is 5 or less, the color change of the formed image is acceptable. ○ and ◎ are acceptable. The evaluation results are shown in Table 6 below.

◎: R, G, B color difference is less than 2 ○: R, G, B color difference is 2 or more and less than 3.5 △: R, G, B color difference is 3.5 or more color difference 5 Less than x: The color difference of any of R, G, and B is 5 or more.

(Image forming method and evaluation method for color blur evaluation)
Each developer (evaluation toner set) in which one of the color toner (four types of YMCK) prepared above and one of the special color toners (W, ME, CL) was combined as shown in Table 6 below was added 5 The developing machine is put into a remodeling machine for the bizhub Pro C6500, which is an image forming apparatus (four types of YMCK are converted to five types of YMCK + special color toner, see FIG. 1), and a transparent OHP sheet is used. An image in which the alphabet “A” (20 pt) of red (M + Y), blue (M + C), and green (C + Y) was drawn in the center of the lowermost special color toner layer of 5 cm square was prepared. The edge of the “A” image in each of the first formed image and the 10,000th formed image can be visually confirmed and the color of the color toner in the lower layer can be identified with a 2000 × optical microscope (Keyence: VHX-2000). Was observed. ○ and ◎ are acceptable. The evaluation results are shown in Table 6 below.

◎: Cannot be discerned by visual observation or optical microscope ○: Cannot be discerned by visual observation, but can be discriminated by lower layer toner color by optical microscope Δ: Can be discerned a little by visual observation, but can clearly identify lower layer toner color by optical microscope ×: It can be clearly discerned visually, and the dot collapse is obvious even with an optical microscope.

(Image forming method and evaluation method for image peeling evaluation)
The image peeling was evaluated as the “fixing rate” shown below. The image density of the secondary color patch portion was measured with a Macbeth reflection densitometer “RD-918” for the 10,000th image produced by the above “secondary color reproducibility”. The image density is an absolute reflection density based on the white reference plate of the measuring instrument, and this measurement part is rubbed 15 times with a load of 22 g / cm ² using plain weave exposed cotton. After rubbing, the image density of the measurement part was measured, and the density ratio before and after rubbing was defined as the fixing rate.

  The evaluation of image peeling was judged as acceptable for practical use if the fixing rate was 80% or more, and it was accepted. The evaluation results are shown in Table 6 below.

  The evaluation criteria for “image peeling” in Table 6 are as follows.

A: Fixing rate of 90% or more O: Fixing rate of 80% or more and less than 90% Δ: Fixing rate of 70% or more and less than 80% ×: Fixing rate of less than 70%

(Measurement of Si / C amount of evaluation toner and evaluation method of measurement result)
Ratio (A / B) of silicon element content A (atom%) and carbon element content B (atom%) on the toner surface containing hydrophobic silica as an external additive (ie, Si / C amount on the toner surface) ) Was measured by XPS (X-ray photoelectron spectroscopy analyzer). Specifically, using an X-ray photoelectron spectrometer “K-Alpha” (manufactured by Thermo Fisher Scientific Co., Ltd.), quantitative analysis of silicon element and carbon element is performed under the following analysis conditions, and each atomic peak area Then, the surface element concentration is calculated using the relative sensitivity factor, and the value (A / B) of the surface element concentration A (atom%) of the silicon element and the surface element concentration B (atom%) of the carbon element is calculated. . In the measurement, the externally-treated toner is put in a hole (diameter 3 mm, depth 1 mm) of a powder measurement plate, and the surface of the measurement plate is used as a measurement sample.

(Measurement condition)
X-ray: Al monochromatic radiation source Acceleration: 12 kV, 6 mA
Beam system: 400 μm
Pass energy: 50eV
Step size: 0.1 eV.

(Evaluation method)
In one type of color toner (four types of YMCK) and special color toner (W, ME, CL) used in each example and comparative example shown in Table 6 below, the value of (A / B) (= Si / C) The amount of the spot color toner is larger than that of the color toner, and the evaluation is “Yes”. Is the value of (A / B) (= Si / C amount) smaller than that of the color toner? Evaluation of the same thing was made "No". In the evaluation of the examples (evaluation of secondary color reproducibility, color bleeding, image peeling, Si / C amount), evaluation using black toner (K) was not performed (for example, dark red K may be used for the expression, and evaluation can be performed in the same manner as in this embodiment using K).

SP1, SP2, and SP3 in Table 6 are the toners having the maximum solubility parameter value (SP value: (cal / cm ³ ) ^1/2 ) of the binder resin of the color toner (four types of YMCK), the first toner, The minimum toner is the second toner and the special color toner (any one of W, ME, and CL) is the third toner, and the solubility parameter values (SP value: (SP value: ( cal / cm ³ ) ^1/2 ) is SP1, SP2, SP3.

  The column “SP1-SP2” represents the difference between the SP value maximum value (SP1) and the minimum value (SP2) of the binder resin of the color toner (four types of YMCK).

  In the column “| SP1-SP3 |”, the maximum SP value (SP1) of the binder resin of the color toner (four types of YMCK) and the binder of the special color toner (any one of W, ME, and CL) are bound. This represents the absolute value of the difference in the SP value (SP3) of the resin.

  In the column “| SP2-SP3 |”, the minimum SP value (SP2) of the binder resin of the color toner (four types of YMCK) and the special color toner (any one of W, ME, and CL) are bound. This represents the absolute value of the difference in the SP value (SP3) of the resin.

  From the results shown in Table 6, by controlling the SP value of the binder resin of the color toner and the binder resin of the color toner and the special color toner within an appropriate numerical value range as in Examples 1 to 19, these colors can be obtained. An image formed using a toner set composed of one type of toner (four types of YMCK) and special color toners (W, ME, CL) may be formed even if a special color toner layer is formed in the lower layer (or upper layer) of the full color image. It was found that the secondary color reproducibility of the color image was good, and a high-quality image with color bleeding and no image peeling could be formed. On the other hand, as in Comparative Examples 1 to 12, when the SP value of the binder resin of the color toner and the binder resin of the color toner and the special color toner is out of the proper numerical range, these color toners (YMCK's (4 types) and special color toners (W, ME, CL). An image formed using a toner set having insufficient secondary color reproducibility, color blur or image peeling. It has been confirmed that it is difficult to form a high-quality image.

  In Examples 6 and 7, the ratio (A / B) of the silicon element content A (atom%) to the carbon element content B (atom%) on the toner surface is more characteristic than the color toner. In Example 7, where the toner is larger (that is, the external additive 2 is used for the special color toner), the color blur is evaluated from ○ to ◎, and the image quality without color blur is further increased. It was found that a good image can be formed. This can also be confirmed from the fact that the same improvement effect is recognized from Comparative Examples 7 and 8. That is, even if the value (A / B) (= Si / C amount) of the special color toner is smaller or the same as that of the color toner, the effect of the present invention is not particularly impaired. It has been found that the effect of the present invention is further improved if the value of A / B) is larger for the special color toner than for the color toner. Compared with Example 6, Example 7 using the external additive formulation 2 improved color bleeding while maintaining other performances, and Comparative Example 8 was compared with Comparative Example 7 from x to Δ. Although the color blur was improved. As described above, when the SP value (the absolute value of the difference) between the special color toner and the color toner is within the range of the present invention, more “hydrophobic silica” exists on the surface of the special color toner than the color toner. Thus, it can be said that the occurrence of color blur can be more effectively suppressed.

  Further, among Examples 1 to 19, in Examples 2 to 5, 8 to 11, and 15 to 18 in which | SP1-SP3 | and | SP2-SP3 | are both 0.4 or more and less than 1.0, color images are displayed. The secondary color reproducibility, color blur, and image peeling were all evaluated as ◎, and it was found that the most excellent high-quality image can be formed. On the other hand, in Examples 1, 6, 7, and 12 to 14 (except for Example 7) in which both | SP1-SP3 | and | SP2-SP3 | The evaluation of color reproducibility and image peeling is ◎, but the evaluation of color blur is ○. In order to improve color blur, both | SP1-SP3 | and | SP2-SP3 | It has been found useful to control below 0. Further, as described above, the ratio (A / B) of the silicon element content A (Atom%) to the carbon element content B (Atom%) on the toner surface is higher than that of the color toner. It has been found that the improvement of the color blur is also an effective means for improving the color blur (see the discussion in Examples 6 and 7 above). In Example 19 where | SP1-SP3 | is 0.4 or more and less than 1.0 and | SP2-SP3 | is 0.15 or more and less than 0.4, the evaluation of secondary color reproducibility is ◎. In order to improve color bleeding and image peeling, both | SP1-SP3 | and | SP2-SP3 | are both 0.4 or more and 1.0 as described above. It has been found useful to control below.

  Further, from Comparative Examples 1 to 12, in Comparative Examples 11 and 12 where SP1-SP2 is 0.15 or more, the evaluation of secondary color reproducibility was x. This is because mixing at the interface where the color toners are superposed cannot be sufficiently performed by heat at the time of fixing, and thus the superposed color toners cannot be sufficiently fused (adhered) to each other by heat melting. It can be said that the color reproducibility of the next color (images of various colors) has deteriorated, and it has become difficult to form a high-quality image.

  In Comparative Examples 1, 2, and 7 to 10, where both | SP1-SP3 | and | SP2-SP3 | are both less than 0.15, the evaluation of color blur is x (comparison in which external additive formulation 2 is used for the special color toner). In Example 8, the evaluation was Δ). This is because if | SP1-SP3 | and | SP2-SP3 | are smaller than 0.15, the color toner and the special color toner are fused and color blurring occurs, which makes it difficult to form a high-quality image. It can be said that it became. Conversely, in Comparative Examples 3 to 6 in which | SP1-SP3 | and | SP2-SP3 | were both 1.0 or more, the evaluation of image peeling was x. This is because when | SP1-SP3 | and | SP2-SP3 | are 1.0 or more, fusion cannot be achieved only by heat fixing, and image peeling occurs, making it difficult to form a high-quality image. It can be said.

31 photoconductor drum,
32 charger,
33. Exposure optical system as image writing means,
34 Development device,
34a Development roller,
36 Intermediate transfer member,
36a Tension roller,
36B backup roller,
37 Primary transfer roller,
37A Secondary transfer member,
38 detection sensor,
47 fixing device,
47a heating roller,
47b pressure belt,
50A, 50B, 50C Paper cassette,
51 feed roller,
52 transport path,
52A paper feed roller,
52B, 52C, 52D Conveying roller,
53 Registration roller,
54 paper discharge roller,
55 Output tray,
70 Secondary transfer device,
100 yellow (Y), magenta (M), cyan (C), black (K) and white (W) process units;
190 Photoconductor cleaning device as an image carrier cleaning means,
190A Intermediate transfer member cleaning device,
GS image forming apparatus,
SC image reader,
CCD line image sensor,
P Image support.

Claims (5)

A toner set including a toner that forms a secondary color and a toner that does not form a secondary color,
The toner having the maximum solubility parameter value (SP value: (cal / cm ³ ) ^1/2 ) of the binder resin of the toner forming the secondary color is the first toner, the toner having the minimum is the second toner, and the secondary toner. The toner that does not form a color is the third toner, and the solubility parameter value (SP value: (cal / cm ³ ) ^1/2 ) of the binder resin of each of the first to third toners is SP (1), SP (2 ), SP (3), the following formulas (1) to (3);
SP (1) -SP (2) <0.15 (1)
0.15 ≦ | SP (1) −SP (3) | <1.0 (2)
0.15 ≦ | SP (2) −SP (3) | <1.0 (3)
The meet,
Toner set before Symbol third toner, see contains a white colorant, characterized in that it contains no crystalline resin. The binder resin solubility parameter value (SP value: (cal / cm ³ ) ^1/2 ) of each of the first to third toners is represented by the following formulas (1), (4), (5);
SP (1) -SP (2) <0.15 (1)
0.4 ≦ | SP (1) −SP (3) | <1.0 (4)
0.4 ≦ | SP (2) −SP (3) | <1.0 (5)
The toner set according to claim 1, wherein:   The toner forming the secondary color and the third toner contain hydrophobic silica, and the content A of the silicon element on the surface of the toner forming the secondary color and the third toner measured by the X-ray photoelectron spectroscopy (XPS) method The ratio (A / B) of (atom%) to carbon element content B (atom%) is larger in the third toner than in the toner that forms the secondary color. The toner set according to 2.   The toner set according to claim 1, wherein the toner forming the secondary color including the first toner and the second toner includes at least a polyester resin. An image forming method using a toner set including a toner that forms a secondary color and a toner that does not form a secondary color,
The toner having the maximum solubility parameter value (SP value: (cal / cm ³ ) ^1/2 ) of the binder resin of the toner forming the secondary color is the first toner, the toner having the minimum is the second toner, and the secondary toner. The toner that does not produce a color is the third toner, and the solubility parameter value (SP value: (cal / cm ³ ) ^1/2 ) of the binder resin of each of the first to third toners is SP (1), SP (2 ), SP (3), the following formulas (1) to (3);
SP (1) -SP (2) <0.15 (1)
0.15 ≦ | SP (1) −SP (3) | <1.0 (2)
0.15 ≦ | SP (2) −SP (3) | <1.0 (3)
The meet,
Image forming method before Symbol third toner, see contains a white colorant, characterized in that it contains no crystalline resin.