Electrostatic charge image developing toner, and image formation method

Abstract

To provide electrostatic charge image developing toner, and an image formation method that are excellent in low temperature fixability and hot offset resistance, and can achieve both improvement in photoluminescent of a fixed image and improvement in post-workability thereof.SOLUTION: Electrostatic charge developing toner includes: a photoluminescent pigment; and toner base particles containing the photoluminescent pigment. The toner base particle contains: a release agent; and an amorphous polyester. The amorphous polyester is a polycondensation product of a polyvalent carboxylic acid and polyhydric alcohol. The amorphous polyester has bisphenol A or a structural unit derived from a bisphenol A derivative. A percentage content of the bisphenol A in the amorphous polyester or the structural unit derived from the bisphenol A derivative is less than 50 mol% with respect to a structural unit of a polyhydric alcohol derivative.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a toner for developing electrostatic images and an image forming method, and more particularly to a toner for developing electrostatic images that has excellent low-temperature fixing properties and hot offset resistance, and can simultaneously improve the brightness of fixed images and improve post-processing properties. [Background technology]

[0002] In recent years, there has been a demand for forming high-value-added images to meet various customer needs. Also, from the viewpoint of energy conservation, low-temperature fixing is desired for toners for developing electrostatic images during image formation.

[0003] For example, Patent Document 1 discloses a technology in which, in a toner for developing electrostatic images containing an amorphous polyester, a bisphenol A derivative is used in the amorphous polyester from the viewpoint of achieving both low-temperature fixability and heat-resistant storage stability. By using such a toner for developing electrostatic images, high-value-added images can be formed.

[0004] In order to give the image high added value, it is also possible to consider, in addition to the above-mentioned points, for example, imparting brilliance to the image.

[0005] Patent Document 2 discloses a technique of incorporating a specific release agent into a toner for developing electrostatic images containing a glittering pigment in order to impart glitter to the image and improve low-temperature fixability. By using such a toner for developing electrostatic images, high-value-added images can be formed.

[0006] However, there is still room for improvement in these techniques. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-66018 [Patent Document 2] Patent Publication No. 2021-43233 Summary of the Invention [Problem to be solved by the invention]

[0008] In order to provide a fixed image with high added value, the above-mentioned Patent Document 1 discloses a technique of using a toner containing a hybrid crystalline polyester, which is a combination of an amorphous polyester and a crystalline polyester, as a binder resin.

[0009] In this technology, a toner for developing electrostatic images is used, which contains an amorphous polyester having structural units derived from a polycarboxylic acid and a polyhydric alcohol, and the polyhydric alcohol component is a derivative of bisphenol A. Hereinafter, the "toner for developing electrostatic images" will also be referred to as "toner."

[0010] The above-mentioned techniques provide a high-value-added fixed image by achieving both low-temperature fixability and heat-resistant storage stability, but there is a problem in that the post-processability of the fixed image deteriorates.

[0011] In order to add value to the fixed image, the aforementioned Patent Document 2 discloses a technique for forming the fixed image using a toner for developing electrostatic images containing a photoluminescent pigment. Hereinafter, the "toner for developing electrostatic images containing a photoluminescent pigment" will also be referred to as "photoluminescent toner."

[0012] In this technology, a specific release agent is added to the glossy toner to improve low-temperature fixability while providing high added value, thereby improving the release property of the glossy toner, improving the low-temperature fixability of the glossy toner, and imparting glossiness to the fixed image.

[0013] The glitter pigment contained in such a glitter toner is generally metallic and therefore hard. Furthermore, the glitter toner contains a hard, crystalline release agent scattered throughout. This results in areas near the surface of the glitter toner where the release agent concentration is locally high, which causes uneven dispersion of the release agent contained in the glitter toner. Hereinafter, this "uneven dispersion of the release agent" will also be referred to simply as "unevenness in the release agent."

[0014] When such a glitter toner is used to form an image using a fixing roller or the like, unevenness in the release agent causes problems such as poor post-processability, such as repelling of varnish applied to the surface of the fixed image for the purpose of imparting gloss to the image, etc. Also, when a laminate is attached to the fixed image, the adhesion of the laminate is reduced, which causes problems such as poor post-processability.

[0015] The present invention has been made in consideration of the above problems and circumstances, and the problem to be solved is to provide a toner for developing electrostatic images and an image forming method which have excellent low-temperature fixing properties and hot offset resistance, and which can achieve both improved brightness of fixed images and improved post-processing properties. [Means for solving the problem]

[0016] In order to solve the above-mentioned problems, the present inventors have investigated the causes of the above-mentioned problems and have found that, in a toner for developing electrostatic images comprising toner base particles containing a photoluminescent pigment, a release agent, and an amorphous polyester, the above-mentioned problems can be solved by setting the content of structural units derived from bisphenol A or a bisphenol A derivative in the amorphous polyester to less than 50 mol % relative to the structural units derived from polyhydric alcohols, thereby arriving at the present invention. That is, the above-mentioned problems of the present invention are solved by the following means.

[0017] 1. A toner for developing electrostatic images, comprising a photoluminescent pigment and toner base particles containing the photoluminescent pigment, the toner base particles contain a release agent and an amorphous polyester, The amorphous polyester is a polycondensation product of a polycarboxylic acid and a polyhydric alcohol, and the amorphous polyester has a structural unit derived from bisphenol A or a bisphenol A derivative, The content of structural units derived from bisphenol A or bisphenol A derivatives in the amorphous polyester is less than 50 mol % relative to the structural units derived from polyhydric alcohols. 1. A toner for developing electrostatic images, comprising:

[0018] 2. The average major axis diameter of the bright pigment is within the range of 3 to 30 μm. 2. The toner for developing electrostatic images according to claim 1,

[0019] 3. The release agent has a structural unit derived from a hydrocarbon, or a structural unit derived from a hydrocarbon and a structural unit derived from an ester, and The content of the hydrocarbon-derived structural unit in the release agent is within a range of 3.0 to 10.0% by mass relative to the toner base particles. 2. The toner for developing electrostatic images according to claim 1,

[0020] 4. The release agent has a hydrocarbon-derived structural unit and an ester-derived structural unit. have 2. The toner for developing electrostatic images according to claim 1,

[0021] 5. The bright pigment is aluminum. 2. The toner for developing electrostatic images according to claim 1,

[0022] 6. Use the toner for developing electrostatic images described in item 1. An image forming method comprising: [Effects of the Invention]

[0023] The above-described means of the present invention can provide a toner for developing electrostatic images and an image forming method that are excellent in low-temperature fixing property and hot offset resistance, and can simultaneously improve the brightness of fixed images and improve post-processing properties.

[0024] The mechanism by which the effects of the present invention are manifested or the mechanism of action is not clear, but is speculated as follows.

[0025] The electrostatic image developing toner of the present invention is a toner for developing electrostatic images, comprising a photoluminescent pigment and toner base particles containing the photoluminescent pigment, wherein the toner base particles contain a release agent and an amorphous polyester, the amorphous polyester is a polycondensate of a polycarboxylic acid and a polyhydric alcohol, and the amorphous polyester has structural units derived from bisphenol A or a bisphenol A derivative, and the content of the structural units derived from bisphenol A or a bisphenol A derivative in the amorphous polyester is less than 50 mol % relative to the structural units derived from the polyhydric alcohol. It is characterized by:

[0026] As mentioned above, the technique of using a bisphenol A derivative in an amorphous polyester and the technique of incorporating a specific release agent into a glitter toner have had problems with post-processing.

[0027] In the present invention, a toner for developing electrostatic images containing the above-mentioned glitter pigment is used to impart high added value to fixed images, thereby achieving excellent low-temperature fixability and hot offset resistance, and simultaneously improving the glitter of fixed images and improving post-processing properties.

[0028] The "post-processing" of a fixed image formed with a glitter toner refers to the first processing step performed on a fixed image having glitter.

[0029] Examples of such processing include applying a varnish to the fixed image, attaching a laminate, and peeling off the laminate. Note that "post-processing" includes a series of processing steps on the varnish or the varnish coating, such as drying or curing the varnish after it has been applied.

[0030] Improved post-processing properties refer to, for example, improved varnish application properties, i.e., the ability to easily apply varnish to the fixed image, and improved lamination properties, i.e., the ability to easily apply a laminate to the fixed image, or the ability to easily peel off a laminate applied to the fixed image.

[0031] When fixing a glitter toner to an image, the glitter pigment contained in the glitter toner needs to be fixed on the recording medium, but the glitter pigment alone will not fix it to the recording medium. Therefore, the glitter pigment can be fixed to the recording medium by coating the toner particles contained in the glitter toner with a binder resin.

[0032] Hereinafter, such a "binder resin that coats toner particles" will also be referred to as a "binder resin." Also, an "image containing toner fixed on a recording medium" will also be referred to as a "fixed image." Note that this "fixed image" also includes cases where the "toner" is a "glossy toner," and an "image obtained by fixing glossy toner on a recording medium" will also be referred to as a "fixed image of glossy toner."

[0033] In order for a fixed image of a glossy toner to exhibit high gloss, the glossy pigment contained in the glossy toner must have a flat shape and the binder resin coating the glossy pigment must be thin, so that when the glossy toner is fixed onto a recording medium, the glossy pigment contained in the glossy toner will be arranged parallel to the recording medium, resulting in an image with even higher gloss.

[0034] In order to form high-value-added images by using a glitter toner, the glitter toner needs to have excellent releasability. In order to impart excellent releasability to the glitter toner, it is conceivable to add a release agent to the glitter toner.

[0035] In the case of a glitter toner containing a release agent, the glitter toner contains hard crystalline release agents scattered throughout the glitter toner. In addition, the glitter pigment contained in the glitter toner is generally hard because it is metallic.

[0036] Therefore, when an image is formed by thermal fixing to a recording medium, the fixing roller physically presses the glossy toner containing a release agent against the toner, and the release agent is pushed by the fixing roller and the glossy pigment contained in the glossy toner, which pushes the release agent, which was originally scattered and crystallized within the glossy toner, onto the toner surface.

[0037] Figure 1 is an example of a conceptual diagram showing how the release agent is pressed by the fixing roller and the photoluminescent pigment. This causes areas on the toner surface where the release agent concentration is locally high, resulting in unevenness of the release agent.

[0038] In Figure 1, "FR1" is the upper fixing roller, "FR2" is the lower fixing roller, "P" is the recording medium, "1" is the photoluminescent pigment, "2" is the resin part, "3" is the release agent, and "10" is the toner base particles. The arrows in Figure 1 indicate the directions of the forces acting on the fixing roller, recording medium, photoluminescent pigment, resin part, release agent, and toner base particles, respectively.

[0039] Such unevenness in the release agent can cause the varnish applied to the surface of the fixed image of the glossy toner to be repelled, for example, in order to impart gloss to the surface, and can also cause problems such as a deterioration in the post-processability of the fixed image, such as a decrease in the adhesion of a laminate when the laminate is attached to the fixed image of the glossy toner.

[0040] Here, hydrocarbon waxes such as paraffin wax and Fischer-Tropsch wax are generally preferably used as release agents useful for improving low-temperature fixability. Fatty acid ester waxes such as carnauba wax are also preferably used. From the viewpoint of low-temperature fixability, hydrocarbon waxes are particularly preferred.

[0041] However, hydrocarbon waxes have a relatively higher polarity than fatty acid ester waxes, and the inclusion of hydrocarbon waxes in glossy toners increases the number of polar groups in the glossy toners, which makes the glossy toners and hydrocarbon waxes incompatible, making it more likely that phase separation will occur and a domain structure will be formed.

[0042] If the above-described phase separation occurs excessively, large domain structures are formed locally in the glossy toner, causing unevenness of the release agent on the fixed image of the glossy toner, which in turn deteriorates the post-processability of the fixed image.

[0043] Here, we consider a case where a fixed image is formed using a glitter toner containing toner base particles containing a release agent and an amorphous polyester, where the amorphous polyester has a structural unit derived from bisphenol A or a bisphenol A derivative.

[0044] Bisphenol A has the property that its polarity makes it difficult for non-polar release agents to disperse. Therefore, when bisphenol A is contained in a glossy toner, the glossy toner and the release agent become incompatible, making it easier to form a domain structure. This causes unevenness in the release agent in the glossy toner, further worsening the post-processability of the fixed image.

[0045] In the glossy toner containing the release agent of the present invention, the content of structural units derived from bisphenol A or bisphenol A derivatives in the amorphous polyester is suppressed to less than 50 mol % relative to the structural units derived from polyhydric alcohols. This is thought to suppress unevenness of the release agent in the glossy toner, thereby achieving excellent low-temperature fixing properties and hot offset resistance, and achieving both improved gloss and improved post-processing properties of the fixed image. [Brief explanation of the drawings]

[0046] [Figure 1] An example of a conceptual diagram showing how the release agent is pushed by the fixing roller and the photoluminescent pigment. [Figure 2] An example of a cross-sectional view of a toner base particle according to the present invention [Figure 3] An example of a conceptual diagram showing how light is reflected on the surface of a photoluminescent pigment [Figure 4] An example of a conceptual diagram showing the shape of a photoluminescent pigment [Figure 5] An example of a schematic diagram showing how light is reflected depending on the average major axis diameter of a bright pigment [Figure 6] A cross-sectional schematic diagram showing an example of a drum tandem type image forming apparatus DETAILED DESCRIPTION OF THE INVENTION

[0047] The electrostatic image developing toner of the present invention is a toner for developing electrostatic images comprising a photoluminescent pigment and toner base particles containing the photoluminescent pigment, wherein the toner base particles contain a release agent and an amorphous polyester, the amorphous polyester is a polycondensate of a polycarboxylic acid and a polyhydric alcohol, and the amorphous polyester has structural units derived from bisphenol A or a bisphenol A derivative, and the content of the structural units derived from bisphenol A or a bisphenol A derivative in the amorphous polyester is less than 50 mol % relative to the structural units derived from the polyhydric alcohol. This feature is a technical feature common to or corresponding to each of the following embodiments (modes).

[0048] In an embodiment of the present invention, it is preferable that the average major axis diameter of the bright pigment is within a range of 3 to 30 μm, from the viewpoint of more easily exhibiting brightness.

[0049] The release agent has a hydrocarbon-derived structural unit or a hydrocarbon-derived structural unit and an ester-derived structural unit, and It is preferable that the content of the hydrocarbon-derived structural unit in the release agent is within a range of 3.0 to 10.0% by mass relative to the toner base particles, from the viewpoint of improving post-processing properties and improving image defects.

[0050] The release agent has a structural unit derived from a hydrocarbon and a structural unit derived from an ester. This is preferable from the viewpoint of achieving both improved post-processing properties and low-temperature fixability.

[0051] The bright pigment is preferably aluminum from the viewpoints of improving reflectivity and reducing costs.

[0052] The image forming method of the present invention is characterized by using the toner for developing electrostatic images of the present invention.

[0053] The present invention, its components, and embodiments for carrying out the present invention will be described in detail below. In this application, the symbol "to" is used to mean that the numerical values ​​before and after it are included as lower and upper limits.

[0054] However, advantages and features provided by one or more embodiments of the present invention will be more fully understood from the following detailed description and the accompanying drawings, which are for illustrative purposes only and are not intended to define the limits of the invention.

[0055] [Toner for developing electrostatic images] 1. Overview The electrostatic image developing toner of the present invention is a toner for developing electrostatic images comprising a photoluminescent pigment and toner base particles containing the photoluminescent pigment, wherein the toner base particles contain a release agent and an amorphous polyester, the amorphous polyester is a polycondensate of a polycarboxylic acid and a polyhydric alcohol, and the amorphous polyester has structural units derived from bisphenol A or a bisphenol A derivative, and the content of the structural units derived from bisphenol A or a bisphenol A derivative in the amorphous polyester is less than 50 mol % relative to the structural units derived from the polyhydric alcohol.

[0056] In this specification, the term "electrostatic image developing toner" is also referred to simply as "toner," and the term "electrostatic image developing toner containing a photoluminescent pigment" is also simply referred to as "photoluminescent toner." The photoluminescent toner contains toner base particles that contain at least a resin and a photoluminescent pigment.

[0057] (1.1) Toner base particles The toner base particles according to the present invention contain a photoluminescent pigment, a release agent, and an amorphous polyester. The photoluminescent pigment is used as a colorant, and the amorphous polyester is used as a binder resin. The toner base particles according to the present invention may also contain other components, such as a binder resin other than the amorphous polyester, an external additive, a charge control agent, and a colorant other than the photoluminescent pigment.

[0058] In this specification, "toner base particles" refer to particles that constitute the base of "toner particles." "Toner particles" refer to toner base particles to which external additives have been added, and an aggregate of toner particles is called "toner." Toner base particles can generally be used as toner particles as they are, but in the present invention, toner base particles to which external additives have been added are used as toner particles. In the following description, when there is no need to particularly distinguish between toner base particles and toner particles, they are also simply referred to as "toner particles."

[0059] Since the glitter pigment cannot be fixed on a recording medium by itself, it can be fixed on the recording medium by coating the glitter pigment with a binder resin. Therefore, the toner base particles according to the present invention are composed of at least the glitter pigment and a resin portion, and the resin portion coats the glitter pigment.

[0060] The "resin portion" refers to the entire portion of the toner base particle excluding the glittering pigment. The resin portion contains at least a binder resin and forms a coating layer that coats the glittering pigment. The fat portion may contain other components such as additives.

[0061] The coating layer may be a single layer or two or more layers, but if the coating layer is too thick, the light incident on the toner particles and the light reflected from the luster pigment will be refracted or absorbed in the resin or on the surface of the resin part, resulting in a decrease in luster.

[0062] Furthermore, if the coating layer has an uneven thickness, the glitter pigment in the toner particles will not be aligned parallel to the surface of the recording medium, resulting in a decrease in glitter. Therefore, it is preferable to make the coating layer, which is the resin part, relatively thin to reduce thickness unevenness.

[0063] 2 is an example of a cross-sectional view of a toner base particle according to the present invention. The toner base particle 10 is composed of at least a photoluminescent pigment 1 and a resin portion 2, and the resin portion 2 coats the photoluminescent pigment 1. The resin portion 2 contains at least a binder resin and forms a coating layer that coats the photoluminescent pigment. The resin portion may contain other components such as additives.

[0064] 3 is an example of a schematic diagram showing how light is reflected from the surface of a glittering pigment. Note that "P" is the recording medium, "LI" is the light incident on the toner base particle, and "LR" is the light reflected by the glittering pigment in the toner base particle. For the glittering toner of the present invention to exhibit excellent glittering properties, it is preferable that incident light LI on the toner base particle 10 is reflected from the surface of the glittering pigment 1, and that the direction of the reflected light is aligned. Therefore, it is preferable that the glittering pigment be flat.

[0065] It is also preferable that the thickness of the resin portion 2 is thin and uniform overall. This prevents the incident light LI on the toner base particles and the reflected light LR from the glittering pigment 1 from being refracted on the surface of the resin portion 2, causing the direction of the reflected light LR to become uneven. Furthermore, when the resin portion is thin, the glittering pigment 1 is more likely to be aligned parallel to the surface of the recording medium P, and the direction of the reflected light LR from the glittering pigment 1 aligned parallel to the surface is more likely to be aligned, thereby improving glitter.

[0066] If the particle size of the toner particles containing the toner base particles is too large, gaps tend to form between the toner particles present in the glitter toner. Also, if the particle size of the toner particles containing the toner base particles is too small, the shape of the toner particles present in the glitter toner becomes closer to a sphere, making it difficult for the glitter pigment to align parallel to the surface of the recording medium. Therefore, it is preferable to control the particle size of the toner particles present in the glitter toner within an appropriate range.

[0067] (Resin part) The structure of the resin portion is not particularly limited and may be a single layer or two or more layers, such as a core-shell structure or a multi-layer structure.

[0068] The "thickness of the resin portion" refers to the length of a perpendicular line from any point on the contour of the outermost surface of a toner base particle to the surface of the luster pigment in a cross-sectional image of the toner base particle obtained by a measurement method using a scanning electron microscope.

[0069] From the viewpoint of brilliance, the thinner the thickness of the resin portion, the better. However, since many brilliance pigments are electrically conductive, if the thickness of the resin portion is too thin, the brilliance pigment is likely to be exposed, which can easily cause poor charging.

[0070] From this perspective, the average thickness of the resin portion measured at any 20 points on the contour of the outermost surface of the toner base particle is preferably within the range of 0.1 to 1.5 μm, more preferably within the range of 0.1 to 0.6 μm, and even more preferably within the range of 0.1 to 0.35 μm.

[0071] The "average thickness of the resin portion" is the arithmetic mean value of the thickness of the resin portion at any 20 points for each toner base particle, and further calculated as the arithmetic mean value for 100 toner base particles.

[0072] The method for measuring the thickness of the resin part is not particularly limited, but it is preferable to measure it by the following method. In addition, by calculating the coefficient of variation in thickness, it can be determined whether the thickness is uniform.

[0073] The thickness of the resin portion is measured at 20 arbitrary points on the contour of the outermost surface of the toner base particle. Note that the distance between the 20 arbitrary points must be at least 100 nm, and points where the resin has peeled off from the photoluminescent pigment and the photoluminescent pigment is exposed, i.e., points with a thickness of 0 nm, are excluded from the arbitrary points.

[0074] The "coefficient of variation in thickness of the resin portion" is the thickness of the resin portion at any 20 points on each toner base particle, which is sorted in descending order. The average of the top five values ​​is taken as the "maximum value" of thickness, and the average of the bottom five values ​​is taken as the "minimum value" of thickness. The coefficient of variation in thickness is calculated using the following formula, and the arithmetic average value for 100 toner base particles is then used. (Equation 2) Variation coefficient = maximum value / minimum value

[0075] The smaller the coefficient of variation (closer to 1), the less variation and unevenness there is in the thickness of the resin portion, meaning that the resin is more uniformly coated on the photosensitive pigment, which can prevent a decrease in photosensitiveness. Also, if there is some variation in the thickness of the resin portion, unevenness will form on the surface of the toner base particles, making cleaning defects less likely to occur.

[0076] From this viewpoint, the coefficient of variation is preferably within the range of 1.0 to 5.0, more preferably within the range of 1.3 to 3.0, and even more preferably within the range of 1.3 to 2.0.

[0077] The variation in the thickness of the resin portion can also be determined by the standard deviation, and the standard deviation of the thickness of the resin portion at any 20 points is preferably within the range of 10 to 80 nm, and more preferably within the range of 10 to 35 nm.

[0078] The specific thickness of the resin portion can be measured by the following method: The coefficient of variation in the thickness of the resin portion can be measured by the following method.

[0079] A sample of toner base particles is stained with 3% ruthenium tetroxide (RuO4) vapor for 10 minutes (room temperature) using a vacuum electron staining device "VSC1R1" (Filgen Co., Ltd.). The stained sample is then dispersed in a photocurable resin "D-800" (JEOL Ltd.) and hardened, embedding the sample in the photocurable resin. Note that "photocurable resin" is a resin that polymerizes (hardens) when exposed to actinic rays such as ultraviolet light or electron beams.

[0080] The embedded sample is processed onto a flat plate using a razor. It is then fixed to a sample holder for ion milling using thermoplastic wax, and ion milling is performed using an ion milling processing device "SM-09010" (manufactured by JEOL Ltd.) to prepare a sample for cross-sectional observation. The conditions are: acceleration voltage: 5.0 kV, beam current: 60 μA, set time: 12 hours, ion species: Ar + Ion milling is performed under the following conditions.

[0081] The cross-section of the dyed cross-section sample is observed using an ultra-high resolution field emission scanning electron microscope "S-4800" (manufactured by Hitachi High-Technologies Corporation). The cross sections of 100 particles within ±3.0 μm of the mass average particle diameter of the toner base particles are selected and photographed.

[0082] The cross-sectional images obtained were taken at 5000x magnification under conditions of an accelerating voltage of 1.0 kV and WD / 3.0 mm, and the photographic images were analyzed using the image processing analysis system "LUZEX-AP" (Nireco Corporation). ) to measure the thickness of the resin portion covering the bright pigment.

[0083] In the obtained cross-sectional image, the resin portion where the binder resin is present is observed as colored black (or gray), while the photoluminescent pigment and embedding resin (photocurable resin) are observed as white, without any color. Therefore, the presence of a resin portion between the photoluminescent pigment and the embedding resin can be confirmed by the contrast. Furthermore, if the resin portion contains a release agent, the release agent is also observed as white, without any color. However, the particle size of the release agent is smaller than that of the photoluminescent pigment, and the photoluminescent pigment and the release agent in the toner base particle can be distinguished by their sizes. Therefore, it can be confirmed that the white portion with the largest size in the major axis direction in the toner base particle corresponds to the photoluminescent pigment.

[0084] Hereinafter, each of the constituent materials of the toner base particles according to the present invention will be described in detail.

[0085] (1.2) Luster pigments The glittering pigment according to the present invention is covered with a resin portion. Hereinafter, the "glittering pigment" will also be referred to as a "glittering pigment particle." The "resin portion covering the glittering pigment" will also be referred to as a "coating layer." When the toner base particles according to the present invention are core-shell type particles, the glittering pigment covered with the resin portion is the core particle, and therefore the glittering pigment will also be referred to as a metal core particle.

[0086] Regarding brilliance, the color is quantified as L * a * b * In the coordinate values ​​of the color system, L * It can be evaluated by calculating the value of L *The larger the value, the more excellent the brilliance.

[0087] Many bright pigments are thin and flat, i.e., flaky (scale-like), and this shape allows the direction of reflected light from the surface of the bright pigment to be aligned, resulting in excellent brightness.

[0088] "Flat" refers to a shape that has a predetermined thickness, and in which dimensions in at least two directions along a plane direction perpendicular to the thickness direction are greater than the thickness dimension, allowing the pigment to be placed stably on a flat surface. This shape is, for example, a shape that resembles a three-dimensional object such as a sphere or a rectangular parallelepiped that has been crushed in one direction, and includes shapes such as flakes, scales, and plates. Specifically, a bright pigment can be said to be flat when its number-average equivalent circle diameter is longer than its number-average maximum thickness.

[0089] The larger the area occupied by the pigment, the more light it can reflect. Furthermore, the more uniformly and parallel the surface of the glitter pigment is to the surface of the recording medium, the more light it can reflect. Since reflecting a large amount of light in this way can exhibit excellent glitter, it is preferable to arrange the toner particles contained in the glitter toner without gaps at the image formation location on the recording medium.

[0090] The average particle size of the glitter pigment is the volume average particle size (D 50 ) may be set to fall within the range of 0.1 to 50 μm.

[0091] The number average equivalent circular diameter and the number average maximum thickness are measured by the following method.

[0092] The photoluminescent pigment is placed on a smooth surface and vibrated to disperse evenly. For 1,000 particles of photoluminescent pigment, the maximum thickness C and the equivalent circular diameter D of the surface as viewed from above are measured at 1,000x magnification using a color laser microscope "VK-9700" (manufactured by Keyence Corporation), and the arithmetic mean value of these is calculated.

[0093] (shape) Figure 4 is an example of a conceptual diagram showing the shape of a bright pigment. In Figure 4, the maximum length of the bright pigment is the long axis particle diameter L, the maximum length in a direction intersecting the long axis particle diameter L is the short axis particle diameter W, and the minimum length in a direction perpendicular to the long axis particle diameter L is the thickness H.

[0094] The "minor axis particle diameter W" is the "maximum length in the direction intersecting with the major axis particle diameter L." The "thickness H" is the "minimum length in the direction perpendicular to the major axis particle diameter L."

[0095] [Average major axis diameter] Figure 5 is an example of a schematic diagram showing how light is reflected depending on the average major axis diameter of the luster pigment. In Figure 5, "1" is the luster pigment, "P" is the recording medium, "10" is the toner base particle, "L" is the major axis particle diameter of the luster pigment, "LI" is the incident light to the toner base particle, and "LR" is the reflected light reflected by the luster pigment in the toner base particle.

[0096] The direction of light reflection for each individual glittering pigment on the recording medium P tends to be essentially irregular, as the glittering pigment contained in each toner varies depending on the unevenness of the recording medium P and how it is contained in the toner. The smaller the pigment, the greater the number of pigments per unit area, which increases the number of irregular reflective surfaces, scattering the light, reducing the intensity of the reflected light and reducing the glitter. Furthermore, if the average major axis diameter L of the glittering pigment is short, the area occupied by the glittering pigment on the recording medium becomes smaller, and the reflected light LR does not pass through the glittering pigment, but is transmitted or scattered by the resin, increasing the number of defective parts BP that reduce reflection efficiency.

[0097] In contrast, if the average major axis diameter L of the luster pigment is long, the luster pigment will occupy a larger area on the recording medium, reducing the number of luster pigments with uneven reflective surfaces, and reducing the number of defective parts BP where the reflected light LR is scattered or diffused in the resin part, reducing the reflection efficiency, thereby improving the luster.

[0098] When the average major axis diameter of the glitter pigment is within the range of 3 to 30 μm, the glitter toner has a thin and flat shape, which makes it easier to align the reflective surface and therefore facilitates glittering, which is preferable. When the average major axis diameter is 3 or more, the glittering effect is not insufficient, and when it is 30 or less, the mechanical strength is sufficient and the color tone is not unstable. Furthermore, the average major axis diameter is more preferably within the range of 5 to 15.

[0099] In addition, if a surface treatment is applied to a bright pigment, the measurement and calculation of the average major axis diameter of the bright pigment shall be performed on the bright pigment before the surface treatment, and shall not include the bright pigment after the surface treatment.

[0100] The method for controlling the shape of the bright pigment so that it has the desired average major axis diameter varies slightly depending on the metal type of the bright pigment, but can generally be achieved by blending the raw materials and adjusting the pH and sintering temperature.

[0101] For example, when the bright pigment is titanium oxide (TiO2), adjusting the blending ratio of the alkali metal salt and the titanium source, the pH, and the firing temperature is effective in controlling the shape of the bright pigment to have the desired average major axis diameter.

[0102] For example, when the bright pigment is ZnO, adjusting the molar ratio of hydroxide ions / zinc ions, which are the raw materials for the bright pigment, and the pH is effective in controlling the shape of the bright pigment to have the desired average major axis diameter.

[0103] For example, when the bright pigment is SnO2, adjusting the mixing ratio of the silicon compound and the tin compound and the firing temperature is effective for controlling the shape of the bright pigment to have the desired average major axis diameter.

[0104] When the luster pigment is a composite metal oxide particle having a metal oxide particle as a core material, other metal oxide particles can be attached to the core metal oxide particle by controlling the shape of the core metal oxide particle.

[0105] For example, the average major axis particle diameter La of the bright pigment can be measured by the following method.

[0106] The bright pigment was observed using a VHX-6000 microscope at a magnification sufficient to confirm its shape, and the observed image was binarized using a LUSEX-AP manufactured by Nireco Corporation. The average of the measured long axis particle diameters L of 100 randomly selected bright pigment particles was taken as the average long axis particle diameter La. The average short axis particle diameter Wa of the bright pigment was taken as the average of the measured short axis particle diameters W of 100 randomly selected bright pigment particles. The average thickness Ha of the bright pigment was taken as the average of the measured thicknesses H of 100 randomly selected bright pigment particles.

[0107] To control the particle size of the toner particles contained in the glitter pigment within an appropriate range, the average major axis particle diameter La of the glitter pigment contained in the toner base particles is preferably within a range of 3 to 30 μm, and more preferably within a range of 5 to 15 μm.

[0108] When the average major axis particle diameter La is 3 μm or more, the toner particles are easily aligned parallel to the surface of the recording medium, resulting in good glitter. When the average major axis particle diameter La is 30 μm or less, gaps are less likely to form between the toner particles when the toner particles are aligned on the surface of the recording medium, resulting in good glitter. In addition, the glitter pigment is less likely to deform even when subjected to external forces during toner particle production or image formation.

[0109] The thinner and flatter the luminous pigment is and the larger its area relative to the paper, the less uneven or torn the reflective surface will be and the more luminous it will appear. However, if the pigment is spread too thinly, it will bend and deform during manufacturing and the printing process, reducing the luminosity of the image.

[0110] The average thickness Ha of the bright pigment is preferably within a range of 25 to 500 nm, and more preferably within a range of 80 to 350 nm.

[0111] When the average thickness Ha is 25 nm or more, light incident on the surface of the luster pigment is less likely to pass through the luster pigment and is more likely to be reflected by the surface, resulting in good luster. Furthermore, the luster pigment is less likely to deform even when subjected to external forces during toner particle production or image formation. On the other hand, when the average thickness Ha is 500 nm or less, the luster pigment is more likely to be aligned parallel to the surface of the recording medium, resulting in good luster.

[0112] When the bright pigment is aluminum flakes, the average thickness Ha is 1 g of the metal component. Water surface spreading area WCA (m 2 / g) and calculate it using the following formula: (Formula 1) Average thickness t(nm)=400 / [WCA(m 2 / g)] The method for calculating the average thickness is described, for example, in Aluminum Paint and Powder, JD Edwards & RI Wray, 3rd Edition, Reinhold Publishing Corp., New York, pages 16-22.

[0113] The "water surface diffusion area" refers to the area occupied by aluminum powder per unit mass when dried aluminum flakes are uniformly diffused on the water surface using the leafing phenomenon, covering it without any gaps.

[0114] The "leafing phenomenon" refers to a phenomenon in which, when a coating film is produced using aluminum flakes as a vehicle to form a coating, aluminum powder floats up and is arranged on the surface of the coating film.

[0115] The water surface diffusion area can be determined in accordance with JIS K 5906-1998 after a certain preliminary treatment.

[0116] The aluminum flakes may be either leafing or non-leafing. In the case of non-leafing type, the procedure is the same as for leafing type except that the sample is pretreated with a 5% solution of stearic acid in mineral spirits. The pretreatment of the sample is described in Journal of Paint Materials, No. 156, pp. 2-16 (published September 1, 1980, by Asahi Chemical Industry Co., Ltd.).

[0117] (kinds) Examples of the luster pigment include metals, metal compounds, glass, crystalline compounds, minerals, etc. The metals also include alloys. When using the luster pigment, various coloring materials such as dyes and pigments may be used in combination to adjust the color tone.

[0118] The bright pigment may be subjected to a surface treatment, and may be coated with various surface treatment agents, silane coupling agents, titanate coupling agents, fatty acids, silica particles, acrylic resins, polyesters, and the like.

[0119] Examples of luster pigments include metal powders such as aluminum, brass, bronze, nickel, stainless steel, zinc, copper, silver, gold, and platinum. Other examples include coated flaky inorganic crystalline substrates such as mica coated with titanium oxide or yellow iron oxide, barium sulfate, layered silicates, and layered aluminum silicates. Other examples include single-crystal plate-like titanium oxide, basic carbonates, bismuth oxychloride, natural guanine, flaky glass powder, and metal-deposited flaky glass powder. These may be used alone or in combination.

[0120] Among these, metal flakes are preferred from the viewpoints of cost, stability, availability, and excellent brilliance, and silver, aluminum, or an aluminum alloy is preferred from the viewpoint of improving reflective properties. In particular, particles made of aluminum or an aluminum alloy are desirable from the viewpoints of cost, weather resistance, light specific gravity, availability, etc.

[0121] Aluminum flakes are more preferred, and metal flakes made of aluminum alone are even more preferred from the viewpoint of reflection characteristics and low cost.

[0122] Examples of metal flakes include simple metal flakes. Other examples include metal flakes obtained by peeling a metal thin film formed by vacuum-depositing an alloy onto a plastic film, and then pulverizing and stirring the peeled metal thin film. Other examples include metal flakes obtained by mixing a metal or alloy powder with a solvent and spreading and / or grinding the powder using a media stirring mill, ball mill, attritor, or the like. Examples include metal flakes obtained by crushing.

[0123] (Content) From the viewpoint of glittering, the content of the glittering pigment is preferably in the range of 25 to 140 mass %, more preferably in the range of 40 to 120 mass %, based on the total mass of the binder resin.

[0124] (Commercially available) Commercially available aluminum flakes may be used, such as Alpaste (registered trademark) WXM-0630, EMERAL (registered trademark) EMR-D5660, and WJC-U75C manufactured by Toyo Aluminum Co., Ltd. Other examples include METALURE (registered trademark) W-52012 IL and Ultravario Aqua PG-24001 manufactured by ECKART Co., Ltd. Other examples include LG (registered trademark) neo Silver#500 (silver) and Gold#500 (gold) manufactured by Oike Kogyo Co., Ltd.

[0125] (1.3) Release agent The toner base particles according to the present invention contain a release agent. When the toner base particles contain a release agent, it is possible to suppress the toner particles from remaining on the fixing member during image formation, and to improve the releasability of the glitter toner.

[0126] (1.3.1) Structural units and content From the viewpoint of both improving the post-processability of the fixed image and improving the low-temperature fixability of the glossy toner, it is preferable that the release agent according to the present invention has a hydrocarbon-derived structural unit, and the content of the hydrocarbon-derived structural unit is within the range of 3.0 to 10.0% by mass relative to the toner base particles. In addition, from the viewpoint of both improving the post-processability of the fixed image and improving the low-temperature fixability of the glossy toner, it is also preferable that the release agent further has an ester-derived structural unit.

[0127] In measuring and analyzing structural units, first, the toner or toner base particles after removing external additives from the toner are subjected to pretreatment by chemical decomposition. There are various types of chemical decomposition, but for example, alkaline hydrolysis and supercritical methanol decomposition are effective for analyzing the composition of polyester, which is a condensation resin. For example, the toner or toner base particles can be decomposed by alkaline hydrolysis at a certain temperature, and then measured and analyzed using known instrumental analysis techniques such as nuclear magnetic resonance (NMR). An example of a specific method for analyzing the resin composition is given below.

[0128] (Alkaline hydrolysis method) Examples of the alkaline hydrolysis method include the following method. The toner and hydrolysis liquid are placed in a high-pressure wet decomposition crucible and heated in an oven at 80 to 150°C for 3 hours. The hydrolysis liquid is a mixture of an alkaline agent, water, and an organic solvent. The oven temperature and heating time may be changed depending on the composition of the sample.

[0129] Examples of the alkaline agent include sodium hydroxide, potassium hydroxide, etc. Examples of the organic solvent include methanol, DMSO (dimethyl sulfoxide), etc. A small autoclave may be used as the container.

[0130] (Method for analyzing resin composition) The molar ratio of each component can be calculated from the peaks derived from bisphenol A derivatives and peaks derived from other polyhydric alcohols in the proton nuclear magnetic resonance ( 1 H-NMR) spectrum of the decomposition liquid obtained after hydrolysis of the toner.

[0131] When the molar ratio of each component cannot be calculated from the 1H-NMR spectrum due to the influence of the matrix component, it is also possible to analyze the composition of the polyhydric alcohol from the GC chromatogram of the decomposition solution. Regarding the molar ratio of the carboxylic acid, it can be analyzed in the same manner by derivatizing the decomposition solution.

[0132] In addition to 1H-NMR measurement, the carbon number and content (ratio) of the constituent components (constituent units) of the polyester can be specified by pyrolysis gas chromatography (GC / MS: Gas Chromatography / Mass Spectrometry).

[0133] For example, specifically, it can be analyzed using a column and detector that have confirmed the ability to detect monomers having a specific structure. Quantitative analysis may also be performed by the standard addition method.

[0134] An example of the detailed pyrolysis conditions and GC / MS measurement conditions is shown below. <Pyrolysis Conditions> Measuring device: PY-2020iD (manufactured by Frontier Lab Co., Ltd.) Mass of measurement: 0.1 mg Heating temperature: 550 °C Heating time: 0.5 minutes <GC / MS Measurement Conditions> Measuring device: QP2010 (manufactured by Shimadzu Corporation) Column: UltraALLOY-5 (inner diameter: 0.25 mm, length: 30 m, thickness: 0.25 μm, manufactured by Frontier Lab Co., Ltd.) Temperature rising range: 40 °C to 320 °C (held at 320 °C) Temperature rising rate: 20 °C / min

[0135] The content of the release agent is preferably in the range of 3.0 to 15.0% by mass, more preferably in the range of 3.0 to 10.0% by mass, based on the total mass of the toner mother particles.

[0136] By setting the content of the release agent to 3.0% by mass or more, the amount of bisphenol contained in the glossy toner can be reduced, and by setting the content of the release agent to 15.0% by mass, the release properties of the glossy toner are improved, and low-temperature fixability and post-processability are also improved, thereby suppressing image defects.

[0137] In the prior art, it has been known that when an amorphous polyester, which is a polycondensate of a polycarboxylic acid and a polyhydric alcohol, has a structural unit derived from bisphenol A or a bisphenol A derivative, it is possible to achieve both low-temperature fixability and heat-resistant storage stability.

[0138] However, in the conventional technology, the amount of bisphenol in the toner must be increased to a certain extent, and if the amount of bisphenol is increased, there is a concern that unevenness in the release agent may occur. Furthermore, unevenness in the release agent may cause image defects. Therefore, it is necessary to keep the amount of bisphenol in the toner as small as possible.

[0139] Here, hydrocarbon waxes such as paraffin wax and Fischer-Tropsch wax are generally preferably used as release agents useful for improving low-temperature fixability. Fatty acid ester waxes such as carnauba wax are also preferably used. From the viewpoint of low-temperature fixability, hydrocarbon waxes are particularly preferred.

[0140] However, hydrocarbon waxes have a relatively higher polarity than fatty acid ester waxes, and the inclusion of hydrocarbon waxes in glossy toners increases the number of polar groups in the glossy toners, which makes the glossy toners and hydrocarbon waxes incompatible, making it more likely that phase separation will occur and a domain structure will be formed.

[0141] If the above-described phase separation occurs excessively, a large domain structure is locally formed in the glossy toner, causing unevenness of the release agent on the fixed image of the glossy toner, which in turn deteriorates post-processing properties.

[0142] Here, we consider the case where a fixed image of a glitter toner is formed using a toner containing toner base particles containing a release agent and an amorphous polyester, where the amorphous polyester has a structural unit derived from bisphenol A or a bisphenol A derivative.

[0143] Bisphenol A has the property that its polarity makes it difficult for non-polar release agents to disperse. Therefore, when bisphenol A is contained in a glossy toner, the glossy toner and the release agent become incompatible, making it easier to form a domain structure. This causes unevenness in the release agent in the glossy toner, further worsening post-processing properties.

[0144] In the glossy toner containing the release agent of the present invention, the content of structural units derived from bisphenol A or bisphenol A derivatives in the amorphous polyester is suppressed to less than 50 mol % relative to the structural units derived from polyhydric alcohols, which suppresses unevenness of the release agent in the glossy toner, thereby achieving excellent low-temperature fixing properties and hot offset resistance, and achieving both improved gloss and improved post-processing properties of the fixed image.

[0145] (1.3.2) Type Examples of the release agent according to the present invention include hydrocarbon waxes and ester waxes. Other known release agents can also be used. These may be used alone or in combination of two or more.

[0146] Examples of hydrocarbon waxes include polypropylene wax, polyethylene wax, polypropylene-polyethylene copolymer wax, microcrystalline wax, paraffin wax, Fischer-Tropsch wax, and Sasol wax.

[0147] Examples of ester waxes include carnauba wax, montan wax, behenyl behenate, behenic acid behenate, trimethylolpropane tribehenate, pentaerythritol tetramyristate, pentaerythritol tetrastearate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1,18-octadecanediol distearate, tristearyl trimellitate, and distearyl maleate.

[0148] (1.3.3) Melting Point From the viewpoint of toner transferability, the melting point of the release agent is preferably 60° C. or higher, and more preferably 70° C. or higher. From the viewpoint of low-temperature fixability, the melting point is preferably 160° C. or lower, more preferably 140° C. or lower, even more preferably 130° C. or lower, and particularly preferably 120° C. or lower.

[0149] The melting point of the release agent can be measured using, for example, a differential scanning calorimeter "Q-100" (manufactured by TA Instruments Japan) according to the following procedure.

[0150] A sample of 0.01 to 0.02 g of release agent is weighed into an aluminum pan, heated to 200°C at a rate of 10°C / min, and cooled from that temperature to -10°C at a rate of 5°C / min. Next, the sample is heated to 180°C at a rate of 10°C / min and measured. The highest endothermic peak temperature observed in the melting endothermic curve obtained is the melting point of the release agent.

[0151] (1.4) Binder resin "Binder resin" refers to a resin that is used as a medium or matrix (parent body) to disperse and retain the internal and external additives contained in the toner particles, and has the function of adhering to the recording medium during the fixing process of the toner image. Also, the aforementioned "resin that binds the toner particles" is called "binder resin." Incidentally, "binder resin" is also called "binder resin."

[0152] Examples of the internal additives include a release agent, a charge control agent, and a colorant. Examples of the external additives include silica and titanium oxide. Examples of the recording medium include paper.

[0153] The toner base particles according to the present invention may use, as a binder resin, a conventionally known binder resin, such as an amorphous resin or a crystalline resin, etc. The toner base particles according to the present invention contain, as a binder resin, at least an amorphous polyester which is a polycondensate of a polycarboxylic acid and a polyhydric alcohol.

[0154] The resin preferably used as the main component of the binder resin according to the present invention is polyester or styrene-acrylic resin. For example, from the viewpoint of coatability when applying varnish to a fixed image, it is preferable to use styrene-acrylic resin as the main component.

[0155] (1.4.1) Polyester When the glitter toner contains polyester, the surface of the image formed by the glitter toner is easily smoothed, and therefore the image is more likely to exhibit excellent glitter and the glitter is less likely to vary. Polyesters include crystalline polyesters, which are crystalline resins, and amorphous polyesters, which are amorphous resins. When aromatic polyesters are included as polyesters in glitter toners, adhesiveness is improved. Aromatic polyesters have acids at the terminals or side chains, and their polarity is thought to improve adhesiveness.

[0156] The term "crystalline resin" refers to a resin that has a clear endothermic peak, rather than a stepwise endothermic change, in an endothermic curve obtained by differential scanning calorimetry (DSC). Specifically, the term "clear endothermic peak" refers to a peak whose half-width is 15°C or less when measured by differential scanning calorimetry (DSC) at a heating rate of 10°C / min.

[0157] The term "amorphous resin" refers to a resin that has a glass transition point (Tg) in an endothermic curve obtained by differential scanning calorimetry (DSC), but does not have a melting point, i.e., a clear endothermic peak when heated.

[0158] (1.4.1.1) Amorphous polyester The toner base particles according to the present invention contain an amorphous polyester. The "amorphous polyester" is a polyester resin that does not have a melting point and has a relatively high glass transition temperature (Tg) when subjected to differential scanning calorimetry (DSC).

[0159] For example, when the toner base particles have a core-shell structure, amorphous polyester can be used as the shell to improve the heat resistance of the toner without impairing its fixability.

[0160] The monomers constituting amorphous polyesters are different from the monomers constituting crystalline polyesters described below, and therefore can be distinguished from crystalline polyesters by performing known instrumental analysis techniques such as nuclear magnetic resonance (NMR).

[0161] Amorphous polyesters are obtained by polycondensation of divalent or higher carboxylic acids and divalent or higher alcohols. Divalent or higher carboxylic acids are also called polycarboxylic acids, and divalent or higher alcohols are also called polyhydric alcohols.

[0162] The specific amorphous polyester is not particularly limited, and any amorphous polyester known in the art may be used, including, for example, vinyl resins, urethane resins, urea resins, and styrene-acrylic modified polyesters.

[0163] (Polycarboxylic Acid) Examples of unsaturated aliphatic polycarboxylic acids used in preparing the amorphous polyester include unsaturated aliphatic dicarboxylic acids, unsaturated aliphatic tricarboxylic acids, unsaturated aliphatic tetracarboxylic acids, etc. Lower alkyl esters and acid anhydrides of these acids can also be used.

[0164] Examples of unsaturated aliphatic dicarboxylic acids include methylenesuccinic acid, fumaric acid, maleic acid, 3-hexenedioic acid, 3-octenedioic acid, and succinic acid substituted with an alkenyl group having 2 to 20 carbon atoms.

[0165] Examples of unsaturated aliphatic tricarboxylic acids include 3-butene-1,2,3-tricarboxylic acid, 4-pentene-1,2,4-tricarboxylic acid, aconitic acid, etc. These polycarboxylic acids may be used alone or in combination of two or more.

[0166] Examples of unsaturated aliphatic tetracarboxylic acids include 4-pentene-1,2,3,4-tetracarboxylic acid.

[0167] Examples of aromatic polycarboxylic acids include aromatic dicarboxylic acids, aromatic tricarboxylic acids, aromatic tetracarboxylic acids, and aromatic hexacarboxylic acids. Lower alkyl esters and acid anhydrides of these may also be used.

[0168] Examples of aromatic dicarboxylic acids include phthalic acid, terephthalic acid, isophthalic acid, t-butylisophthalic acid, tetrachlorophthalic acid, chlorophthalic acid, nitrophthalic acid, p-phenylenediacetic acid, 2,6-naphthalenedicarboxylic acid, 4,4′-biphenyldicarboxylic acid, and anthracenedicarboxylic acid.

[0169] Examples include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 1,2,5-benzenetricarboxylic acid (trimesic acid), 1,2,4-naphthalenetricarboxylic acid, and hemimellitic acid.

[0170] Examples of aromatic tetracarboxylic acids include pyromellitic acid and 1,2,3,4-butanetetracarboxylic acid.

[0171] An example of the aromatic hexacarboxylic acid is mellitic acid.

[0172] (Polyhydric alcohol) As the polyhydric alcohol used in preparing the amorphous polyester, from the viewpoint of controlling compatibility with the crystalline polyester resin, it is preferable to use unsaturated aliphatic polyhydric alcohols, aromatic polyhydric alcohols, and derivatives thereof. These polyhydric alcohols may be used alone or in combination with two or more kinds, and saturated aliphatic polyhydric alcohols may be used in combination as long as an amorphous resin can be obtained.

[0173] However, when producing the toner for developing electrostatic images of the present invention, bisphenol A, which is an aromatic polyhydric alcohol, or an alkylene oxide adduct of bisphenol A, or a derivative thereof must be used.

[0174] Examples of the unsaturated aliphatic polyhydric alcohol include unsaturated aliphatic diols such as 2-butene-1,4-diol, 3-butene-1,4-diol, 2-butyne-1,4-diol, 3-butyne-1,4-diol, and 9-octadecene-7,12-diol. Derivatives of these can also be used.

[0175] Examples of the aromatic polyhydric alcohol include bisphenols such as bisphenol A and bisphenol F, alkylene oxide adducts of bisphenols such as their ethylene oxide adducts and propylene oxide adducts, 1,3,5-benzenetriol, 1,2,4-benzenetriol, and 1,3,5-trihydroxymethylbenzene. Derivatives of these may also be used. Among these, it is preferable to use bisphenol A compounds such as ethylene oxide adducts and propylene oxide adducts of bisphenol A, particularly from the viewpoint of ease of optimizing thermal properties.

[0176] The number of carbon atoms in the trihydric or higher polyhydric alcohol is not particularly limited, but it is preferable that the number of carbon atoms is within the range of 3 to 20, as this makes it easier to optimize the thermal properties.

[0177] (Weight average molecular weight) The weight average molecular weight (Mw) of the amorphous polyester is not particularly limited, but is preferably in the range of 5,000 to 100,000, and more preferably in the range of 5,000 to 50,000. When the weight average molecular weight (Mw) is 5,000 or more, the heat-resistant storage stability of the toner can be improved, and when it is 100,000 or less, the low-temperature fixability can be further improved. The weight average molecular weight (Mw) can be measured by gel permeation chromatography (GPC).

[0178] (Method for producing amorphous polyester) The specific method for producing the amorphous polyester is not particularly limited, and the resin can be produced by polycondensing a polycarboxylic acid and a polyhydric alcohol using a known esterification catalyst. This "polycondensation" is also called "esterification."

[0179] The catalyst that can be used in producing the amorphous polyester, the polycondensation temperature, and the polycondensation time are not particularly limited, and are the same as those for the crystalline polyester described below.

[0180] (1.4.1.2) Styrene-acrylic resin The amorphous polyester contained in the toner base particles according to the present invention is preferably a styrene-acrylic resin from the viewpoint of thermal properties. Furthermore, this resin can suppress excessive bleeding of the release agent from the fixed image of the glossy toner, improve the fixing separation property, and suppress contamination inside the machine due to the release agent. Furthermore, this resin is preferable from the viewpoint of a good balance of compatibility with additives.

[0181] When the toner base particles according to the present invention contain a styrene-acrylic resin and an ester-based release agent, the compatibility is well balanced, and low-temperature fixability and suppression of tacking can be easily achieved.

[0182] Styrene-acrylic resin is an amorphous vinyl resin, which is obtained by polymerization of at least vinyl monomers. Vinyl resin is a polymer of vinyl compounds, and it is preferable that the toner base particles contain vinyl resin, from the viewpoint of easy control of thermoplasticity.

[0183] Examples of vinyl resins include acrylate resins, styrene-acrylate resins, and ethylene-vinyl acetate resins.

[0184] Among the above, styrene-acrylic ester resin (styrene-acrylic resin) is preferred from the viewpoint of plasticity during thermal fixing. "Styrene-acrylic ester resin" is also called "styrene-acrylic resin."

[0185] The amorphous vinyl resin can easily control phase separation from the crystalline resin. The amorphous vinyl resins may be used alone or in combination of two or more.

[0186] Styrene-acrylic resins are formed by addition polymerization of at least a styrene monomer and a (meth)acrylic acid ester monomer.

[0187] (styrene monomer) Styrene monomers include styrene, which is represented by the structural formula CH2=CH-C6H5, as well as styrene derivatives having known side chains or functional groups in the styrene structure.

[0188] Examples of styrene monomers include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-tert-butylstyrene, and pn-hexylstyrene. Examples of suitable styrenes include pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, and pn-dodecylstyrene.

[0189] ((Meth)acrylic acid ester monomer) (Meth)acrylic acid ester monomers include acrylic acid esters and methacrylic acid esters represented by CH(R1)=CHCOOR2, as well as acrylic acid ester derivatives and methacrylic acid ester derivatives having known side chains or functional groups in the ester structure, where R1 represents a hydrogen atom or a methyl group, and R2 represents an alkyl group having 1 to 24 carbon atoms.

[0190] Examples of the (meth)acrylic acid ester monomer include acrylic acid ester monomers and methacrylic acid esters.

[0191] Examples of acrylic acid ester monomers include methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate (2EHA), stearyl acrylate, lauryl acrylate, and phenyl acrylate.

[0192] Examples of methacrylic acid esters include methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, and dimethylaminoethyl methacrylate.

[0193] In this specification, the term "(meth)acrylic acid ester monomer" is a general term for "acrylic acid ester monomer" and "methacrylic acid ester monomer," and means one or both of them. For example, "methyl (meth)acrylate" means one or both of "methyl acrylate" and "methyl methacrylate."

[0194] The (meth)acrylic acid ester monomer may be one or more types. For example, a copolymer can be formed using a styrene monomer and two or more types of acrylic acid ester monomers. Also, a copolymer can be formed using a styrene monomer and two or more types of methacrylic acid ester monomers. Also, a copolymer can be formed using a styrene monomer in combination with an acrylic acid ester monomer and a methacrylic acid ester monomer.

[0195] (glass transition temperature) The styrene-acrylic resin preferably has a glass transition temperature (Tg) in the range of 25 to 60°C, and more preferably has a glass transition temperature (Tg) in the range of 35 to 55°C.

[0196] In this specification, the glass transition temperature (Tg) of a resin is a value measured using a Diamond DSC (manufactured by PerkinElmer Japan Co., Ltd.). The measurement procedure involves sealing 3.0 mg of a measurement sample (resin) in an aluminum pan and setting it in a holder. An empty aluminum pan was used as a reference.

[0197] The measurement conditions were a measurement temperature of 0 to 200 ° C, a temperature rise rate of 10 ° C / min, a temperature fall rate of 10 ° C / min, and heat-cool-heat temperature control. Analysis was performed based on the data from the second heat, and the extension of the baseline before the rise of the first endothermic peak, A tangent line showing the maximum slope is drawn from the rising part of the first peak to the peak apex, and the intersection point is taken as the glass transition temperature.

[0198] (Weight average molecular weight) The weight average molecular weight (Mw) of the styrene-acrylic vinyl resin can be measured, for example, by gel permeation chromatography (GPC). The weight average molecular weight (Mw) is preferably in the range of 10,000 to 100,000.

[0199] In this specification, the molecular weight of a resin measured by GPC is a value measured as follows.

[0200] Specifically, using the HLC-8120GPC instrument (manufactured by Tosoh Corporation) and the TSKgel guardcolumn SuperHZ-L and TSKgel SuperHZM-M columns (manufactured by Tosoh Corporation), the column temperature was maintained at 40°C, and tetrahydrofuran (THF) was passed through as a carrier solvent at a flow rate of 0.2 mL / min. The measurement sample (resin) was dissolved in tetrahydrofuran to a concentration of 1 mg / mL under dissolution conditions of 5 minutes of treatment at room temperature using an ultrasonic disperser.

[0201] The sample solution is then filtered through a 0.2 μm pore membrane filter to obtain a sample solution. 10 μL of this sample solution is then injected into the device together with the carrier solvent, and the sample is detected using a refractive index detector (RI detector). The molecular weight distribution of the sample is calculated using a calibration curve measured using monodisperse polystyrene standard particles. Ten polystyrene samples are used for the calibration curve measurement.

[0202] (Content) The lower limit of the styrene-acrylic resin content is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 50% by mass or more, and particularly preferably 60% by mass or more, based on the total amount of binder resin. If it is 5% by mass or more, the compatibility with the crystallizable resin is good, and low-temperature fixability is good.

[0203] (Method of manufacturing styrene-acrylic resin) The method for producing the styrene-acrylic resin is not particularly limited, and examples thereof include a method in which polymerization is carried out by a known polymerization method such as bulk polymerization, solution polymerization, emulsion polymerization, miniemulsion polymerization, or dispersion polymerization using any polymerization initiator commonly used in the polymerization of the above-mentioned monomers.

[0204] As the polymerization initiator, known oil-soluble or water-soluble polymerization initiators can be used.

[0205] Examples of oil-soluble polymerization initiators include azo-based or diazo-based polymerization initiators, and peroxide-based polymerization initiators.

[0206] Examples of the azo or diazo polymerization initiator include 2,2'-azobis-(2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, and azobisisobutyronitrile.

[0207] Examples of peroxide-based polymerization initiators include benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide, dicumyl peroxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, 2 , 2-bis-(4,4-t-butylperoxycyclohexyl)propane, and tris-(t-butylperoxy)triazine.

[0208] When synthesizing styrene-acrylic resin particles using emulsion polymerization, a water-soluble radical polymerization initiator can be used as the polymerization initiator.

[0209] Examples of the water-soluble polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate, azobisaminodipropane acetate, azobiscyanovaleric acid and its salts, and hydrogen peroxide.

[0210] (1.4.1.3) Hybrid amorphous polyester The amorphous polyester according to the present invention is preferably a hybrid amorphous polyester in which an amorphous polyester polymer segment and a vinyl polymer segment having a styrene-derived structural unit are chemically bonded.

[0211] More specifically, the amorphous polyester is preferably a hybrid amorphous polyester having a graft copolymer structure in which an amorphous polyester polymer segment and a vinyl polymer segment having a styrene-derived structural unit are chemically bonded.

[0212] When such a hybrid amorphous polyester is used for the shell and the hybrid ratio is within the range of 70 to 99 mass %, the core particles are easily coated. The "hybrid ratio" refers to the mass % of the amorphous polyester polymer segment relative to the total amount of the hybrid amorphous polyester.

[0213] Therefore, even when a fixed image is formed, the external additives present on the surface of the toner base particles are less likely to be buried, and the presence of the external additives can be maintained on the boundary lines between adjacent toner base particles.

[0214] The connection between the external additives present on the boundary line in this way becomes a route for the movement of charges, further suppressing the sticking phenomenon.

[0215] The constituent components and content ratios of each segment in the hybrid amorphous polyester can be identified by, for example, NMR measurement or methylation reaction Py-GC / MS measurement.

[0216] (amorphous polyester polymer segment) The amorphous polyester polymer segment is a portion derived from a known polyester obtained by a polycondensation reaction of a polycarboxylic acid component and a polyhydric alcohol component, similar to that of the amorphous polyester. The amorphous polyester polymer segment is a polymer segment for which no clear endothermic peak is observed in differential scanning calorimetry (DSC) of the toner.

[0217] The amorphous polyester polymer segment is not particularly limited as long as it is as defined above. For example, with respect to a resin having a structure in which other components are copolymerized into a main chain of an amorphous polyester polymer segment, or a resin having a structure in which an amorphous polyester polymer segment is copolymerized into a main chain made of other components, if a toner containing this resin does not show a clear endothermic peak as described above, the resin corresponds to the hybrid amorphous polyester having an amorphous polyester polymer segment as defined in the present invention.

[0218] (vinyl polymerized segment) The hybrid amorphous polyester contains, in addition to the amorphous polyester polymer segment, a vinyl polymer segment containing a styrene-derived structural unit. The vinyl polymer segment is not particularly limited as long as it contains a styrene-derived structural unit. In consideration of the properties, a styrene-(meth)acrylic acid ester polymerized segment (styrene-acrylic polymerized segment) is preferred.

[0219] The styrene-acrylic polymerized segment is formed by addition polymerization of at least a styrene monomer and a (meth)acrylic acid ester monomer. Specific examples of monomers that can form the styrene-acrylic polymerized segment are the same as those described for the styrene-acrylic resin above, so further description is omitted here.

[0220] The content of styrene-derived structural units in the vinyl polymerized segments is preferably within a range of 40 to 95% by mass relative to the total amount of the vinyl polymerized segments.

[0221] The content of the structural units derived from the (meth)acrylic acid ester monomer in the vinyl polymerization segment is preferably within a range of 5 to 60% by mass relative to the total amount of the vinyl polymerization segment.

[0222] Furthermore, the vinyl polymerized segment is preferably formed by addition polymerization of a compound for chemically bonding to the amorphous polyester polymerized segment in addition to the styrene monomer and (meth)acrylic acid ester monomer.

[0223] Specifically, it is preferable to use a compound that forms an ester bond with a hydroxy group [—OH] derived from the polyhydric alcohol component or a carboxy group [—COOH] derived from the polycarboxylic acid component contained in the crystalline polyester polymer segment.

[0224] Therefore, the vinyl polymerized segment is preferably formed by further polymerizing a compound which is addition polymerizable with styrene and (meth)acrylic acid ester monomers and has a carboxy group [—COOH] or a hydroxy group [—OH].

[0225] Examples of such compounds include compounds having a carboxy group, such as acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumaric acid, maleic acid monoalkyl ester, and itaconic acid monoalkyl ester.

[0226] Other examples include compounds having a hydroxy group, such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and polyethylene glycol mono(meth)acrylate.

[0227] The content of the structural units derived from the above compounds in the vinyl polymerized segment is preferably within a range of 0.5 to 20% by mass relative to the total amount of the vinyl polymerized segment.

[0228] The method for forming the styrene-acrylic polymerized segment is not particularly limited, and examples thereof include a method of polymerizing monomers using a known oil-soluble or water-soluble polymerization initiator as mentioned in the above-mentioned method for producing a styrene-acrylic resin.

[0229] The content of the vinyl polymer segment in the hybrid amorphous polyester is preferably within a range of 2 to 25% by mass.

[0230] (Polycarboxylic Acid) Examples of the polycarboxylic acid component include oxalic acid, succinic acid, maleic acid, adipic acid, 6-methyladipic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid, and decanedicarboxylic acid. carboxylic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, fumaric acid, citraconic acid, diglycolic acid, cyclohexane-3,5-diene-1,2-dicarboxylic acid, malic acid, citric acid, hexahydroterephthalic acid, malonic acid, pimelic acid, tartaric acid, mucic acid, phthalic acid, isophthalic acid, terephthalic acid, tetrachlorophthalic acid, chlorophthalic acid, nitrophthalic acid, p-carboxyphenylacetic acid, p-phenylenediacetic acid, m-phenylenediglycolic acid, p-phenylenediglycolic acid, o-phenylenediglycolic acid, diphenylacetic acid, diphenyl-p,p'-dicarboxylic acid, naphthalene-1,4-dicarboxylic acid, naphthalene-1,5-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, anthracenedicarboxylic acid, and dicarboxylic acids such as dodecenylsuccinic acid.

[0231] Other examples include trimellitic acid, pyromellitic acid, naphthalenetricarboxylic acid, naphthalenetetracarboxylic acid, pyrenetricarboxylic acid, and pyrenetetracarboxylic acid.

[0232] These polycarboxylic acids can be used alone or in combination. Among these, it is preferable to use aliphatic unsaturated dicarboxylic acids such as fumaric acid, maleic acid, and mesaconic acid, aromatic dicarboxylic acids such as isophthalic acid and terephthalic acid, succinic acid, and trimellitic acid.

[0233] (Polyhydric alcohol) Examples of polyhydric alcohol components include dihydric alcohols such as ethylene glycol, propylene glycol, butanediol, diethylene glycol, hexanediol, cyclohexanediol, octanediol, decanediol, dodecanediol, bisphenol A ethylene oxide adduct, and bisphenol A propylene oxide adduct.

[0234] Further examples include trivalent or higher polyols such as glycerin, pentaerythritol, hexamethylolmelamine, hexaethylolmelamine, tetramethylolbenzoguanamine, and tetraethylolbenzoguanamine.

[0235] These polyhydric alcohol components can be used alone or in combination of two or more. Among these, dihydric alcohols such as bisphenol A ethylene oxide adduct and bisphenol A propylene oxide adduct are preferred.

[0236] (Method for producing hybrid amorphous polyester) As a method for producing the hybrid amorphous polyester, an existing general scheme can be used. Representative methods include the following three (1) to (3).

[0237] (1) A method for producing a hybrid amorphous polyester by polymerizing a vinyl polymerization segment in advance and then carrying out a polymerization reaction to form an amorphous polyester polymerization segment in the presence of the vinyl polymerization segment. (2) A method in which an amorphous polyester polymer segment and a vinyl polymer segment are formed in advance and then bonded to produce a hybrid amorphous polyester. (3) A method for producing a hybrid amorphous polyester by polymerizing an amorphous polyester polymer segment in advance and then carrying out a polymerization reaction to form a vinyl polymer segment in the presence of the amorphous polyester polymer segment.

[0238] Among the above, those containing styrene-acrylic resin and aromatic polyester improve adhesion to varnish. Varnish contains acrylic polymers, which makes them compatible.

[0239] (1.4.1.4) Crystalline polyester The glitter toner of the present invention preferably contains a crystalline polyester as a binder resin, because this improves the flexibility of the toner base particles and makes it easier to properly fix external additives, and is also preferred from the viewpoint of low-temperature fixability. When the glitter toner of the present invention contains a crystalline polyester, melting becomes faster in the fixing step, and fixing strength increases.

[0240] Crystalline polyesters are known polyesters obtained by polycondensation of polycarboxylic acid components and / or hydroxycarboxylic acids with polyhydric alcohol components. In differential scanning calorimetry (DSC), these resins exhibit a clear melting peak rather than a stepwise change in endothermic heat.

[0241] (Polycarboxylic Acid) The polycarboxylic acid component for forming the crystalline polyester is a compound containing two or more carboxy groups in one molecule.

[0242] Examples of polycarboxylic acids include saturated aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, aromatic dicarboxylic acids, trivalent or higher polycarboxylic acids, and anhydrides or alkyl esters of these carboxylic acids having 1 to 3 carbon atoms.

[0243] As the polycarboxylic acid component for forming the crystalline polyester, it is preferable to use a saturated aliphatic dicarboxylic acid. These may be used alone or in combination of two or more.

[0244] Examples of saturated aliphatic dicarboxylic acids include succinic acid, sebacic acid, and dodecanedioic acid.

[0245] Examples of the alicyclic dicarboxylic acid include cyclohexanedicarboxylic acid.

[0246] Examples of aromatic dicarboxylic acids include phthalic acid, isophthalic acid, and terephthalic acid.

[0247] Examples of trivalent or higher polyvalent carboxylic acids include trimellitic acid and pyromellitic acid.

[0248] (Polyhydric alcohol) The polyhydric alcohol component for forming the crystalline polyester is a compound containing two or more hydroxy groups in one molecule.

[0249] Examples of polyhydric alcohols include aliphatic diols and trihydric or higher polyhydric alcohols.

[0250] As the polyhydric alcohol component for forming the crystalline polyester, it is preferable to use an aliphatic diol, which may be used alone or in combination of two or more.

[0251] Examples of the aliphatic diol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, neopentyl glycol, and 1,4-butenediol.

[0252] Examples of trihydric or higher polyhydric alcohols include glycerin, pentaerythritol, trimethylolpropane, and sorbitol.

[0253] (Melting Point) The melting point of the crystalline polyester is preferably in the range of 65 to 85° C., more preferably in the range of 75 to 85° C. When the melting point of the crystalline polyester is in this range, sufficient low-temperature fixability and excellent image storage stability can be obtained. The melting point of the crystalline polyester can be controlled by the resin composition.

[0254] The melting point of the crystalline polyester is the peak-top temperature of the melting peak in the second heating process in a DSC curve obtained by differential scanning calorimetry of the above-mentioned crystalline polyester alone, and can be measured by DSC using a Diamond DSC (manufactured by PerkinElmer Co., Ltd.) When there are multiple melting peaks in the DSC curve, the peak-top temperature of the melting peak with the largest endothermic heat is taken as the melting point.

[0255] Specifically, the sample is sealed in an aluminum pan, Kit No. B0143013, and set in the sample holder of a thermal analyzer, Diamond DSC (manufactured by PerkinElmer), and the temperature is changed in the order of heating, cooling, and heating.

[0256] During the first heating, the temperature is raised from room temperature (25°C), and during the second heating, from 0°C, to 150°C at a rate of 10°C / min and held at 150°C for 5 minutes. During cooling, the temperature is lowered from 150°C to 0°C at a rate of 10°C / min and held at 0°C for 5 minutes. The temperature at the top of the endothermic peak in the endothermic curve obtained during the second heating is measured as the melting point.

[0257] (acid number) The acid value of the crystalline polyester is preferably within a range of 5 to 30 mgKOH / g, more preferably within a range of 10 to 25 mgKOH / g, and even more preferably within a range of 15 to 25 mgKOH / g. The acid value is the mass of potassium hydroxide (KOH) required to neutralize the acid contained in 1 g of a sample, expressed in mg units. The acid value of a resin is measured according to the following procedure in accordance with JIS K0070-1992.

[0258] [Preparation of reagents] Dissolve 1.0 g of phenolphthalein in 90 mL of ethyl alcohol (95% by volume) and add ion-exchanged water to make 100 mL to prepare a phenolphthalein solution. Dissolve 7 g of JIS special grade potassium hydroxide in 5 mL of ion-exchanged water and add ethyl alcohol (95% by volume) to make 1 liter. Place in an alkali-resistant container to avoid contact with carbon dioxide and leave for 3 days, then filter to prepare a potassium hydroxide solution. Standardization follows the instructions in JIS K0070-1992.

[0259] [Main test] Accurately weigh 2.0 g of the crushed sample into a 200 mL Erlenmeyer flask, add 100 mL of a 2:1 volumetric mixture of toluene and ethanol, and dissolve for 5 hours. Next, add a few drops of the prepared phenolphthalein solution as an indicator, and titrate with the prepared potassium hydroxide solution. The endpoint of the titration is when the indicator's light red color lasts for approximately 30 seconds.

[0260] [Blank test] The same procedure as in the main test above is carried out, except that no sample is used and only a mixed solution of toluene and ethanol in a volume ratio of 2:1 is used. The titration results of the main test and blank test are substituted into the following equation (1): Enter the acid value and calculate the acid value. Formula (1) A=[(CB)×f×5.6] / S A: Acid value (mgKOH / g) B: Amount of potassium hydroxide solution added during blank test (mL) C: Amount of potassium hydroxide solution added during this test (mL) f: Factor of 0.1 mol / L potassium hydroxide ethanol solution S: mass of sample (g)

[0261] (number average molecular weight) The number average molecular weight (Mn) of the crystalline polyester is preferably in the range of 2500 to 5000, more preferably in the range of 3000 to 4500. From the viewpoint of low-temperature fixability and gloss stability, the number average molecular weight (Mn) of the crystalline polyester is preferably in the range of 3000 to 12500, more preferably in the range of 4000 to 11000. When the number average molecular weight (Mn) is in the above range, it is easy to achieve a balance between fixability and heat resistance. Furthermore, sufficient strength can be obtained in the fixed image. The number average molecular weight (Mn) of the crystalline polyester can be measured by gel permeation chromatography (GPC).

[0262] The molecular weight measurement by GPC is carried out as follows. Specifically, the apparatus "HLC-8320" (manufactured by Tosoh Corporation) and the columns "TSKgel guardcolumn SuperHZ-L" and "TSKgel SuperHZM-M" (manufactured by Tosoh Corporation) were used, and the column temperature was maintained at 40°C while tetrahydrofuran (THF) was used as the carrier solvent at a flow rate of 0.2 ml / min.

[0263] The measurement sample (crystalline polyester) is dissolved in tetrahydrofuran to a concentration of 1 mg / ml under dissolution conditions of treating with an ultrasonic disperser at room temperature for 5 minutes, and then the solution is filtered through a membrane filter with a pore size of 0.2 μm to obtain a sample solution. 10 μL of this sample solution is injected into the device together with the above-mentioned carrier solvent, and detected using a refractive index detector (RI detector). The molecular weight distribution of the measurement sample is calculated using a calibration curve measured using monodisperse polystyrene standard particles.

[0264] The standard polystyrene sample for calibration curve measurement was a polystyrene with a molecular weight of 6 × 10 manufactured by Pressure Chemical Co. 2 , 2.1×10 3 , 4×10 3 , 1.75×10 4 , 5.1×10 4 , 1.1×10 5, 3.9×105, 8.6×105, 2×106, and 4.48×106 are used, and at least 10 standard polystyrene samples are measured to create a calibration curve.

[0265] (Weight average molecular weight) The weight average molecular weight (Mw) of the crystalline polyester is preferably within a range of 10,000 to 100,000, more preferably within a range of 15,000 to 80,000, and even more preferably within a range of 20,000 to 50,000.

[0266] When the weight-average molecular weight (Mw) is within the above range, it is easy to achieve a balance between fixability and heat resistance. Furthermore, sufficient strength is obtained in the fixed image. Furthermore, in the toner production, the crystalline polyester is not pulverized during emulsion stirring, and the glass transition temperature (Tg) of the toner is maintained constant, thereby maintaining the thermal stability of the toner. The weight-average molecular weight (Mw) can be determined from the molecular weight distribution measured by gel permeation chromatography (GPC).

[0267] (Crystalline polyester content) The toner base particles according to the present invention may contain a crystalline polyester as a binder resin. From the viewpoint of obtaining sufficient low-temperature fixability, the content of the crystalline polyester relative to the toner base particles is preferably within a range of 1 to 40% by mass, and more preferably within a range of 7 to 15% by mass.

[0268] When the content of the crystalline polyester in the toner base particles is 1% by mass or more, a sufficient plasticizing effect is obtained, resulting in sufficient low-temperature fixability, and when the content is 20% by mass or less, the toner has sufficient thermal stability and stability against physical stress.

[0269] (Method for producing crystalline polyester) The method for producing the crystalline polyester is not particularly limited, and the crystalline polyester can be produced by a general polyester polymerization method in which the above-mentioned polycarboxylic acid and polyhydric alcohol are reacted in the presence of a catalyst. For example, it is preferable to produce the crystalline polyester by using a direct polycondensation method or an ester exchange method depending on the type of monomer.

[0270] Furthermore, a linear aliphatic hydroxycarboxylic acid can be used in combination with the polycarboxylic acid and / or polyhydric alcohol.

[0271] Examples of linear aliphatic hydroxycarboxylic acids for forming crystalline polyesters include 5-hydroxypentanoic acid, 6-hydroxyhexanoic acid, 7-hydroxypentanoic acid, 8-hydroxyoctanoic acid, 9-hydroxynonanoic acid, 10-hydroxydecanoic acid, 12-hydroxydodecanoic acid, 14-hydroxytetradecanoic acid, 16-hydroxyhexadecanoic acid, 18-hydroxyoctadecanoic acid, lactone compounds cyclized from these hydroxycarboxylic acids, and alkyl esters with alcohols having 1 to 3 carbon atoms. These may be used alone or in combination of two or more.

[0272] Furthermore, when forming the crystalline polyester, it is preferable to use a polycarboxylic acid and a polyhydric alcohol component, since this makes it easier to control the reaction and allows a resin having a desired molecular weight to be obtained.

[0273] 〔catalyst〕 Examples of catalysts that can be used in the production of crystalline polyester include titanium catalysts and tin catalysts.

[0274] Examples of titanium catalysts include titanium tetraethoxide, titanium tetrapropoxide, titanium tetraisopropoxide, and titanium tetrabutoxide.

[0275] Examples of tin catalysts include dibutyltin dichloride, dibutyltin oxide, and diphenyltin oxide.

[0276] [Use ratio in the production of crystalline polyester] The ratio of the polycarboxylic acid component and the polyhydric alcohol component used in the production of the crystalline polyester is as follows:

[0277] The ratio of the hydroxyl groups [OH] of the polyhydric alcohol component to the carboxyl groups [COOH] of the polycarboxylic acid component, expressed as an equivalent ratio [OH] / [COOH], is preferably within the range of 1.5 / 1 to 1 / 1.5, and more preferably within the range of 1.2 / 1 to 1 / 1.2.

[0278] [Polymerization temperature of crystalline polyester] The polymerization temperature for the crystalline polyester is preferably within a range of 150 to 250° C. The polymerization time is preferably within a range of 0.5 to 10 hours. During the polymerization of the crystalline polyester, the pressure in the reaction system may be reduced as necessary.

[0279] (1.5) External additives It is preferable to attach an external additive to the surface of the toner base particles according to the present invention. The external additive may be inorganic or organic fine particles, and by attaching the external additive, the chargeability, fluidity, antiblocking property, etc. of the toner can be controlled.

[0280] Examples of inorganic fine particles include silica, alumina, titania, zirconia, tin oxide, zinc oxide, and aluminum stearate. Other examples include stearic acid compounds such as zinc stearate, and titanic acid compounds such as strontium titanate and zinc titanate.

[0281] Examples of organic fine particles include fine resin particles such as melamine resin and polytetrafluoroethylene resin. Also included are homopolymers such as styrene and methyl methacrylate. Also included are fine particles made of copolymers of these. These may be used alone or in combination of two or more.

[0282] Among the external additives, silica is preferred, and from the viewpoint of toner transferability, hydrophobic silica that has been subjected to a hydrophobic treatment is more preferred.

[0283] A hydrophobic treatment agent can be used to hydrophobize the surface of silica particles. Examples of the hydrophobic treatment agent include hexamethyldisilazane (HMDS), dimethyldichlorosilane (DMDS), silicone oil, octyltriethoxysilane (OTES), and methyltriethoxysilane.

[0284] It is preferable that the particle diameter of the external additive added to the toner base particles, that is, the number average particle diameter, is within the range of 20 to 300 μm from the viewpoint of stabilizing the charge amount and preventing scratches on the fixing member.

[0285] A particle size of 20 μm or more prevents the corners of the glitter pigment from directly contacting the fixing roller, and a particle size of 300 μm or less improves the fluidity of the glitter toner and facilitates the transfer of external additives from the toner particles to the carrier particles, thereby stabilizing charge fluctuations, particularly during high-coverage printing.

[0286] The number average particle size of the external additive added to the glitter toner is specifically measured by the following method.

[0287] A 30,000x magnification photograph of the glitter toner is taken using a scanning electron microscope, and this photograph is scanned. The external additives present on the glitter toner surface in the photograph are binarized using an image processing analyzer LUZEX AP (manufactured by Nireco Corporation), and the horizontal Feret diameters of 100 particles per type of external additive are calculated, and the average value is taken as the number-average particle diameter.

[0288] Here, the "horizontal Feret diameter" refers to the length of the side parallel to the x-axis of the circumscribing rectangle when the image of the external additive is binarized. When the number average primary particle diameter of the external additive is small and it exists on the toner surface as an aggregate, the particle diameter of the primary particles forming the aggregate is measured.

[0289] The content of the external additive in the toner particles contained in the glitter toner is From the viewpoints of conductivity, fluidity, and transferability, the content of the external additive is preferably in the range of 0.05 to 5% by mass, more preferably in the range of 0.1 to 3.0% by mass, and even more preferably in the range of 0.3 to 3.0% by mass, based on the total mass of the glitter toner before treatment with the external additive.

[0290] From the viewpoint of the fluidity and durability of the glossy toner, the coverage rate of the toner base particles with the external additive is preferably 50% or more, more preferably 80% or more, even more preferably 90% or more, and particularly preferably 95% or more.

[0291] The coverage of the toner base particles with the external additive can be calculated by the following formula: When two or more types of external additives are used in combination, the total coverage with the external additives is the sum of the coverages calculated for each external additive.

[0292] (Formula 3) Coverage rate (%)=(√3 / 2π)×{(D·ρt) / (d·ρs)}×C×100

[0293] In the above formula, D is the volume-based median particle diameter of the toner base particles (D 50 ) [μm], d is the number average particle size of the external additive [μm], ρt is the specific gravity of the toner base particles, ρs is the specific gravity of the external additive, and C is the mass ratio of the external additive to the toner base particles (external additive / toner base particles).

[0294] (1.6) Charge control agent The glitter toner of the present invention may contain a charge control agent, which can adjust the chargeability of the toner base particles.

[0295] Examples of charge control agents include nigrosine dyes, metal salts of naphthenic acid, metal salts of higher fatty acids, alkoxylated amines, quaternary ammonium salt compounds, azo metal complexes, metal salts of salicylic acid, and metal complexes of salicylic acid.

[0296] The content of the charge control agent is preferably in the range of 0.1 to 10% by mass, more preferably in the range of 0.5 to 5% by mass, based on the total mass of the binder resin.

[0297] From the viewpoint of charging stability, the content of the charge control agent is preferably within a range of 0.01 to 10% by mass relative to the total mass of the binder resin, more preferably within a range of 0.2 to 5% by mass, even more preferably within a range of 0.2 to 3.0% by mass, and particularly preferably within a range of 0.2 to 2% by mass.

[0298] (1.7) Colorants The glitter toner of the present invention may contain a colorant other than the glitter pigment.

[0299] As colorants other than the luster pigment, for example, carbon black, magnetic materials, dyes, pigments, etc. can be used arbitrarily, and these colorants can be used alone or in combination of two or more as needed.

[0300] The content of the colorant is preferably in the range of 1 to 30% by mass, more preferably in the range of 2 to 20% by mass, based on the total amount of the glitter toner.

[0301] When the content of the colorant is within the range of 1 to 30% by mass with respect to the entire glitter toner, color reproducibility of the image can be ensured.

[0302] The volume average particle size of the colorant is preferably within a range of 10 to 1000 nm, more preferably within a range of 50 to 500 nm, and particularly preferably within a range of 80 to 300 nm.

[0303] The toner base particles according to the present invention may further contain a colored colorant, as desired. As the colored colorant, known inorganic or organic colorants such as those shown below can be used depending on the color of the glitter toner.

[0304] The content of the colored colorant is preferably in the range of 1 to 30% by mass, more preferably in the range of 2 to 20% by mass, based on the total mass of the binder resin.

[0305] Examples of colored colorants include yellow colorants, magenta colorants, cyan colorants, black colorants, and white colorants. These may be used alone or in combination of two or more.

[0306] As the yellow colorant, for example, a known yellow colorant that is usually used in yellow toner can be used.

[0307] Specific examples of dyes include CI Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, and 162.

[0308] Further, examples of pigments include CI Pigment Yellow 14, 17, 74, 93, 94, 138, 155, 180, and 185. Mixtures of these can also be used.

[0309] As the magenta colorant, for example, a known magenta colorant that is usually used in magenta toner can be used.

[0310] Specific examples of dyes include CI Solvent Red 1, 49, 52, 58, 63, 111, and 122.

[0311] Examples of pigments include CI Pigment Red 5, 48:1, 53:1, 57:1, 122, 139, 144, 149, 166, 177, 178, and 222. Mixtures of these can also be used.

[0312] As the cyan colorant, for example, a known cyan colorant that is usually used in cyan toner can be used.

[0313] Specific examples of dyes include CI Solvent Blue 25, 36, 60, 70, 93, and 95.

[0314] Examples of pigments that can be used include CI Pigment Blue 1, 7, 15, 60, 62, 66, 76, and 15:3, and mixtures thereof can also be used.

[0315] As the black colorant, for example, known black colorants that are usually used in black electrophotographic toners can be used.

[0316] Specific examples include carbon black, magnetic materials, and titanium black.

[0317] Examples of carbon black include channel black, furnace black, acetylene black, thermal black, and lamp black.

[0318] Examples of magnetic materials include ferromagnetic metals such as iron, nickel, and cobalt, alloys containing these ferromagnetic metals, ferromagnetic metal compounds such as ferrite and magnetite, and alloys that do not contain ferromagnetic metals but exhibit ferromagnetism when heat-treated.

[0319] Examples of alloys that become ferromagnetic when heat treated include Heusler alloys such as manganese-copper-aluminum and manganese-copper-tin, and chromium dioxide.

[0320] The white colorant may be an inorganic compound or an organic compound.

[0321] Examples of inorganic compounds include heavy calcium carbonate, light calcium carbonate, titanium dioxide, aluminum hydroxide, satin white, talc, calcium sulfate, barium sulfate, zinc oxide, magnesium oxide, magnesium carbonate, amorphous silica, colloidal silica, white carbon, kaolin, calcined kaolin, delaminated kaolin, aluminosilicate, sericite, bentonite, and smexite.

[0322] Examples of the organic compound include polystyrene resin particles and urea formalin resin particles.

[0323] (1.8) Other ingredients Examples of other components include magnetic powder, flowability improvers, conductivity adjusters, and reinforcing fillers such as fibrous materials, as well as antioxidants and cleaning improvers.

[0324] 2. Developer The glitter toner of the present invention can be used as a one-component developer, but may also be mixed with a carrier and used as a two-component developer.

[0325] The carrier is mixed with the toner particles to form a two-component magnetic toner, and the carrier may be any known magnetic particle that can be contained in a toner.

[0326] Examples of magnetic particles include iron, steel, nickel, cobalt, ferrite, and magnetite, as well as particles containing magnetic materials such as alloys of these with aluminum and lead.

[0327] The carrier may be a coated carrier in which the surfaces of the magnetic particles are coated with a resin or the like, or a resin-dispersed carrier in which the magnetic particles are dispersed in a binder resin.

[0328] Examples of resins that can be used to coat the surfaces of the magnetic particles include olefin resins, styrene resins, styrene-acrylic resins, silicone resins, polyesters, and fluororesins.

[0329] Examples of the binder resin include acrylic resin, styrene-acrylic resin, polyester, fluororesin, and phenolic resin.

[0330] The average particle size of the carrier is within the range of 20 to 100 μm on a volume basis. It is preferable that the thickness is within the range of 25 to 80 μm.

[0331] The average particle size of the carrier can be measured by a laser diffraction particle size distribution measuring device equipped with a wet disperser, such as HELOS manufactured by SYMPATEC.

[0332] The content of the carrier is preferably within the range of 2 to 10% by mass with respect to the total mass of the toner particles and the carrier.

[0333] 3.Other (3.1) Shape of toner base particles (particle size) The particle size of the toner base particles is the volume-based median particle size (D 50 ) is preferably in the range of 5 to 50 μm, more preferably in the range of 10 to 30 μm, and even more preferably in the range of 12 to 30 μm. If it is in the above range, high reproducibility can be obtained even for extremely fine dot images at the 1200 dpi level. In the present invention, the "volume-based median particle diameter (D 50 )" means the particle size at which the cumulative volume frequency calculated by volume fraction is 50% calculated from the smallest particle size.

[0334] The particle size of the toner particles can be controlled by the concentration of the aggregating agent used during production, the amount of organic solvent added, the fusion time, the composition of the binder resin, and the like.

[0335] The volume-based median particle size of the toner particles (D 50For example, a measuring device such as a Multisizer 3 (manufactured by Beckman Coulter) connected to a computer system equipped with data processing software Software V3.51 can be used.

[0336] Specifically, a measurement sample (toner) is added to a surfactant solution, mixed, and then ultrasonically dispersed to prepare a toner particle dispersion. For example, a surfactant solution prepared by diluting a neutral detergent containing a surfactant component with pure water by 10 times for the purpose of dispersing toner particles is used as the surfactant solution.

[0337] This toner particle dispersion is pipetted into a beaker containing ISOTON II (manufactured by Beckman Coulter) in a sample stand until the concentration indicated on the measuring device reaches 8%. By achieving this concentration, reproducible measurements can be obtained.

[0338] In the measurement device, the number of particles measured is 25,000, the aperture diameter is 100 μm, and the measurement range of 2 to 60 μm is divided into 256 parts to calculate the frequency value. The particle diameter of the largest 50% of the volume fraction is taken as the volume-based median diameter (D 50 ) is obtained.

[0339] (average circularity) To improve the stability of chargeability and low-temperature fixability, the toner particles preferably have an average circularity in the range of 0.930 to 1.000, more preferably 0.950 to 0.995. When the average circularity is within this range, individual toner particles are less likely to be crushed. This can suppress contamination of the frictional charge-imparting member, stabilize the chargeability of the toner, and improve the quality of the formed image.

[0340] The average circularity of toner particles can be measured using an FPIA-2100 (manufactured by Sysmex Corporation). Specifically, the measurement sample (toner) is mixed with an aqueous solution containing a surfactant, and then dispersed by ultrasonic dispersion treatment for 1 minute. Thereafter, the FPIA-2100 (manufactured by Sysmex Corporation) is used to measure the average circularity of toner particles under the measurement condition of HPF (high magnification imaging) mode, with an HPF detection number of 3000 to 1000. Photographs are taken at the appropriate density of 10,000. If the number of HPF detections is within the above range, reproducible measurement values ​​can be obtained.

[0341] From the photographed particle image, the circularity of each toner particle is calculated according to the following formula (I), and the circularity of each toner particle is added up and divided by the total number of toner particles to obtain an average circularity.

[0342] Formula (I): Circularity = (perimeter of a circle with the same projected area as the particle image) / (perimeter of the projected particle image)

[0343] (3.2) Manufacturing method of toner base particles The electrostatic image developing toner of the present invention includes a photoluminescent pigment and toner base particles containing the photoluminescent pigment. The toner base particles also contain a release agent and an amorphous polyester which is a polycondensate of a polycarboxylic acid and a polyhydric alcohol.

[0344] In the kneading and grinding method, which is commonly used to manufacture toner, resins, pigments, and other additives are heated, melted, and kneaded, then rolled and cooled, and then ground and classified to obtain toner. With this method, it is difficult to control the thickness of the resin coating on the photoluminescent pigment, i.e., to make it relatively thin and reduce thickness variations. Furthermore, in some cases, the photoluminescent pigment may bend during grinding and classification, causing the direction of reflected light from the photoluminescent pigment surface to become misaligned, resulting in poor photoluminescence and undesirable results.

[0345] Therefore, the toner base particles according to the present invention are preferably produced by a known method such as an emulsion polymerization aggregation method or an emulsion aggregation method.

[0346] According to the emulsion polymerization aggregation method, a dispersion of binder resin particles obtained by emulsion polymerization and a dispersion of effective pigment particles are mixed together with particles of a release agent, a charge control agent, etc., which are optionally added, and then these are aggregated, associated, or fused together until particles of a desired particle size are obtained, and then an external additive is added to obtain the desired particle size.

[0347] According to the emulsion aggregation method, a dispersion of binder resin particles obtained by dropping a solution in which a binder resin is dissolved into a poor solvent is mixed with a dispersion of bright pigment particles together with particles of a release agent, a charge control agent, etc., which are optionally added, and these are then aggregated, associated, or fused together until particles of a desired particle size are obtained, and then an external additive is added to obtain the desired particle size.

[0348] The toner base particles according to the present invention are prepared so that the content of structural units derived from bisphenol A or a bisphenol A derivative in the amorphous polyester is less than 50 mol % relative to the mol % of structural units derived from polyhydric alcohols, thereby suppressing unevenness of the release agent in the glitter toner, thereby achieving excellent low-temperature fixability and hot offset resistance, and simultaneously improving the glitter of the fixed image and improving post-processability.

[0349] The thickness and thickness variation coefficient of the resin portion that coats the glitter pigment contained in the glitter toner of the present invention can be appropriately adjusted by the amount of resin added and the stirring and mixing time.

[0350] When a pigment other than the glitter pigment is contained in the toner base particles, two or more types of pigments are internally added to the toner particles, which tends to increase the amount of pigment added. Therefore, when preparing a dispersion of pigment particles, it is preferable to add a surfactant to the dispersion to improve the dispersion stability of the pigment.

[0351] [Image forming method] (overview) The image forming method of the present invention is characterized by using the electrostatic image developing toner of the present invention, and therefore, unevenness of the release agent in the electrostatic image developing toner, i.e., the glitter toner, is suppressed, thereby making it possible to form an image having excellent glitter and excellent post-processability of the fixed image.

[0352] The toner for developing electrostatic images of the present invention is used in, for example, a known electrophotographic image forming method, specifically, it is preferably used in an image forming method having the following steps:

[0353] 1) An electrostatic image forming process in which an electrostatic image is formed on the surface of an image carrier. 2) A developing step in which the electrostatic image formed on the surface of the image carrier is developed with a photoluminescent toner to form a photoluminescent toner image. 3) a transfer step of transferring the glossy toner image onto a transfer-receiving material; 4) a fixing step of fixing the glossy toner image transferred onto the surface of the transfer medium;

[0354] The transfer step 3 may use an intermediate transfer member that mediates the transfer of the glossy toner image from the image carrier to the transferee, and may further include a cleaning step of removing residual toner from the surface of the image carrier after transfer.

[0355] The image obtained by the image forming method is preferably an image having a glossy toner image formed with the glossy toner of the present invention and a color toner image formed with at least a color toner, such as a yellow toner, a magenta toner, a cyan toner, or a black toner, on top of the glossy toner image formed with the glossy toner of the present invention.

[0356] Furthermore, it is more preferable that the glossy toner image has a color metallic color, and a color toner image formed of at least a color toner is formed on top of the glossy toner image formed of the glossy toner. Because the glossy toner image formed by the glossy toner of the present invention has high gloss, even when used as a lower layer of a color toner image, the glossiness is fully exhibited in the image, and a good color metallic image is particularly suitably formed.

[0357] The recording medium may be any commonly used one, and may also be referred to as "media," "recording material," "recording paper," or "recording paper."

[0358] The recording medium is not particularly limited as long as it can hold a toner image formed by a known image forming method using an image forming apparatus or the like.

[0359] Examples of recording media include coated printing paper such as plain paper ranging from thin paper to thick paper, fine paper, art paper, coated paper, etc. Other examples include commercially available Japanese paper, postcard paper, plastic film for overhead projectors, cloth, soft transparent film, synthetic paper such as Yupo paper, etc.

[0360] The image forming method of the present invention is particularly effective when forming images on special recording media such as colored paper, black paper, and transparent film.

[0361] (Image forming device) An image forming apparatus used when forming an image using the electrophotographic toner of the present invention will be described.

[0362] As an image forming apparatus, for example, an image forming unit having a developing machine and a photosensitive member is mounted for each toner, and the toner images formed on each photosensitive member are sequentially transferred onto an intermediate transfer member and superimposed, and then transferred onto a recording medium all at once, and fixed by a heat roller method, to form a visible image (fixed image). Examples include a drum tandem system that forms a photoimage.

[0363] Fig. 6 is a schematic cross-sectional view showing an example of a drum tandem type image forming apparatus suitable for use in the present invention. Fig. 5 shows an example in which the glitter toner of the present invention and color toners including yellow toner (By), magenta toner (Bm), cyan toner (Bc), and black toner (Bk) are used.

[0364] The image forming apparatus GS shown in Figure 6 is what is called a tandem color image forming apparatus. The image forming apparatus GS has image forming units that form toner images using photosensitive toner and color toner along the direction of movement of an intermediate transfer body 36. The photosensitive toner images and color toner images formed on the photosensitive bodies of the image forming units are then multiple-transferred and superimposed onto the intermediate transfer body, and then collectively transferred onto a recording medium.

[0365] 6, an original image placed on the image reading device SC is scanned and exposed by an optical system and read into a line image sensor CCD. An analog signal photoelectrically converted by the line image sensor CCD is subjected to analog processing, A / D conversion, shading correction, image compression processing, etc. in an image processing section, and then an image data signal is sent to an exposure optical system 33 as an image writing means.

[0366] There are no particular restrictions on the intermediate transfer body 36, and a drum type or an endless belt type can be used. The following describes the case where an endless belt type is used.

[0367] In FIG. 6, five sets of process units 100 are provided around the periphery of the intermediate transfer body 36 for forming toner images of each color, yellow (Y), magenta (M), cyan (C), black (K), and a glossy toner image (W).

[0368] The process units 100, as means for forming color toner images and glossy toner images, are arranged in a vertical column along the intermediate transfer body 36, with respect to the rotation direction of the intermediate transfer body 36, which is the vertical direction indicated by the arrow in Figure 6. The process units 100 are arranged in the following order: a process unit Y for yellow (Y), a process unit M for magenta (M), a process unit C for cyan (C), a process unit K for black (K), and a process unit W for glossy toner images (W).

[0369] All five process units 100 have a common structure and each includes a photosensitive drum 31, a charger 32 as a charging means, an exposure optical system 33 as an image writing means, a developing device (developing machine) 34, and a photosensitive drum cleaning device 190 as a photosensitive drum cleaning means.

[0370] The photosensitive drum 31 is formed by forming a photosensitive layer having a thickness of about 20 to 40 μm on the outer periphery of a cylindrical substrate made of a metal member such as aluminum and having an outer diameter of about 40 to 100 mm. The photosensitive drum 31 is driven by a drive source (not shown) and rotates in the direction of the arrow at a speed of about 80 to 280 mm / s, for example, with the substrate grounded. The photosensitive drum 31 also rotates at a linear velocity of preferably 220 mm / s.

[0371] An image forming unit consisting of a charger 32 as a charging means, an exposure optical system 33 as an image writing means, and a developing device (developing machine) 34 is arranged around the photosensitive drum 31 in the direction of rotation of the photosensitive drum 31 as indicated by the arrow in the figure.

[0372] The charger 32 serving as a charging means is attached in close proximity to and facing the photosensitive drum 31 in a direction parallel to the rotation axis of the photosensitive drum 31 .

[0373] 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. The charger 32 performs charging by corona discharge of the same polarity as the toner, thereby applying a uniform potential to the photosensitive drum 31. In this embodiment, the charging action is a negative charging action.

[0374] The exposure optical system 33, which is an image writing means, rotates and scans laser light emitted from a semiconductor laser (LD) light source (not shown) in the main scanning direction using a rotary polygon mirror (no reference numeral).The light also passes through an fθ lens (no reference numeral), a reflecting mirror (no reference numeral), etc., and exposes (writes an image) the photosensitive drum 31 with an electrical signal corresponding to the image signal, forming an electrostatic charge image corresponding to the original image on the photosensitive layer of the photosensitive drum 31.

[0375] The developing device 34 as a developing means contains two-component developers of yellow (Y), magenta (M), cyan (C) and black (K) charged to the same polarity as the charging polarity of the photosensitive drum 31, as well as a glossy toner image (W).

[0376] The two-component developer for each color contains yellow (Y), magenta (M), cyan (C), and black (K), as well as yellow toner (By), magenta toner (Bm), cyan toner (Bc), and black toner (Bk), corresponding to the photoluminescent toner image (W), and the photoluminescent toner of the present invention.

[0377] The developing device 34 includes a developing roller 34a, which is a cylindrical developer carrier made of non-magnetic stainless steel or aluminum material and has a thickness in the range of 0.5 to 1 mm and an outer diameter in the range of 15 to 25 mm, for example.

[0378] The developing roller 34a is kept out of contact with the photosensitive drum 31 by abutting rollers (not shown), with a predetermined gap, for example, 100 to 1000 μm, and rotates in the same direction as the rotation of the photosensitive drum 31. During development, a DC voltage of the same polarity as the toner or a development bias voltage in which an AC voltage is superimposed on a DC voltage is applied to the developing roller 34a, thereby performing reverse development on the exposed portion on the photosensitive drum 31. Note that the polarity in the above "same polarity as the toner" is negative in this embodiment.

[0379] It is preferable to use a resin belt as the intermediate transfer body 36. The resin belt used has a volume resistivity of 1.0×10 7 ~1.0×10 9 It is preferable that the surface resistivity of the resin belt is in the range of 1.0×10 10 ~1.0×10 12 It is preferably in the range of Ω / □.

[0380] The resin belt is preferably a semiconductive resin film in which a conductive material is dispersed in engineering plastic such as modified polyimide, thermosetting polyimide, ethylene tetrafluoroethylene copolymer, polyvinylidene fluoride, or nylon alloy.

[0381] The thickness of the resin film is preferably within the range of 0.05 to 0.5 mm.

[0382] Alternatively, the resin belt may be a semi-conductive rubber belt made of silicone rubber, urethane rubber, or the like with a conductive material dispersed therein, and the thickness of the rubber belt is preferably within the range of 0.5 to 2 mm.

[0383] 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.

[0384] The primary transfer roller 37 as the first transfer means for each color is made of a roller-shaped conductive member using foam rubber such as silicone and urethane, and is provided facing the photosensitive drum 31 of each color across the intermediate transfer body 36. In addition, the primary transfer roller 37 presses against the back surface of the intermediate transfer body 36 to form a transfer area between the intermediate transfer body 36 and the photosensitive drum 31.

[0385] A DC constant current of the opposite polarity to that of the toner is applied to the primary transfer roller 37 by constant current control, and a transfer electric field is formed in the transfer area, causing the toner image on the photosensitive drum 31 to be transferred onto the intermediate transfer body 36. In this embodiment, the polarity of the "opposite polarity to that of the toner" is positive.

[0386] The toner image transferred onto the intermediate transfer body 36 is then transferred onto a recording medium P. A detection sensor 38 is provided on the periphery of the intermediate transfer body 36 to measure the density of the patch image toner.

[0387] In addition, a cleaning device 190A is provided to clean residual toner on the intermediate transfer body .

[0388] Furthermore, a secondary transfer device 70 is provided to clean the patch image toner on the secondary transfer member 37A.

[0389] (Image forming method using image forming apparatus) Next, an image forming method using the image forming apparatus shown in FIG. 6 will be described.

[0390] When image recording starts, a photosensitive drum drive motor (not shown) starts, the yellow (Y) photosensitive drum 31 rotates in the direction indicated by the arrow in the figure, and the Y charger 32 applies a potential to the Y photosensitive drum 31.

[0391] After the Y photosensitive drum 31 is given an electric potential, the Y exposure optical system 33 exposes (writes an image) the Y photosensitive drum 31 with an electric signal corresponding to the first color signal, i.e., the Y image data, and an electrostatic charge image corresponding to the yellow (Y) image is formed on the Y photosensitive drum 31.

[0392] This electrostatic image is reverse-developed by the Y developing device 34, and a toner image (By) made of yellow toner (By) is formed on the Y photosensitive drum 31. The Y toner image (By) formed on the Y photosensitive drum 31 is transferred onto the intermediate transfer body 36 by a primary transfer roller 37 serving as a primary transfer means.

[0393] Next, a potential is applied to the M photoconductor 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) using an electrical signal corresponding to a first color signal, i.e., M image data, and an electrostatic charge image corresponding to the magenta (M) image is formed on the M photoconductor drum 31.

[0394] This electrostatic image is reverse-developed by the M developing device 34, and a toner image (Bm) made of magenta toner (Bm) is formed on the M photosensitive drum 31. The M toner image (Bm) formed on the M photosensitive drum 31 is transferred onto the intermediate transfer body 36 by the primary transfer roller 37 as primary transfer means, superimposed on the Y toner image (By).

[0395] By a similar process, a toner image (Bc) made of cyan toner (Bc) formed on the cyan (C) photosensitive drum 31 and a toner image (Bk) made of black toner (Bk) formed on the black (K) photosensitive drum 31 are sequentially superimposed and formed on the intermediate transfer body 36. Also, a superimposed color toner image made of a toner image (By), a toner image (Bm), a toner image (Bc), and a toner image (Bk) is formed on the circumferential surface of the intermediate transfer body 36.

[0396] Next, the photosensitive drum 31 for the glossy toner image (W) is rotated in the direction shown by the arrow in the figure, and a potential is applied to the photosensitive drum 31 for W by the charger 32 for W.

[0397] After a potential is applied to the W photoconductor drum 31, the W exposure optical system 33 exposes (writes an image) the W photoconductor drum 31 with a first color signal, i.e., an electrical signal corresponding to the W image data. An electrostatic charge image corresponding to the glossy toner image (W) is then formed on the W photoconductor drum 31. This electrostatic charge image is reverse-developed by the W developing device 34, and a glossy toner image made of glossy toner is formed on the W photoconductor drum 31.

[0398] The glossy toner image formed on the W photosensitive drum 31 is transferred onto the intermediate transfer body 36 by a primary transfer roller 37 serving as a primary transfer means. As a result, a superimposed color toner image consisting of a toner image (By), a toner image (Bm), a toner image (Bc), and a toner image (Bk) is formed on the circumferential surface of the intermediate transfer body 36, and a glossy toner image is further formed on the color toner image.

[0399] Any toner remaining on the circumferential surface of each photosensitive drum 31 after transfer is cleaned off by a cleaning blade of a photosensitive drum cleaning device 190 .

[0400] Meanwhile, recording media P as recording paper stored in paper feed cassettes 50A, 50B and 50C are fed by a feed roller 51 and a feed roller 52A provided in each of paper feed cassettes 50A, 50B and 50C.

[0401] The recording medium P is transported on the transport path 52 by transport rollers 52B, 52C, and 52D, passes through a registration roller 53, and is transported to a secondary transfer member 37A as a secondary transfer means to which a voltage of the opposite polarity to that of the toner is applied. Note that the polarity of the "opposite polarity to that of the toner" is positive in this embodiment.

[0402] In the transfer region of the secondary transfer member 37A, the superimposed color toner image formed on the intermediate transfer body 36 and the glossy toner image on the color toner image are transferred together onto the recording medium P with the glossy toner image facing the recording medium P. This results in an image in which the glossy toner image and the color toner image are layered in that order on the recording medium.

[0403] The recording medium P onto which the image in which the color toner image is layered in that order on top of the glossy toner image has been transferred is heated and pressurized in a nip formed by the heating roller 47a and pressure belt 47b of the fixing device 47. The recording medium P is then sandwiched between the paper discharge rollers 54 and placed on the paper discharge tray 55 outside the machine. The toner is fixed to the recording medium P by being heated and pressurized in the nip.

[0404] After the glossy toner image and the color toner image are transferred onto the recording medium P by the secondary transfer member 37A as a secondary transfer means, residual toner remaining on the intermediate transfer body 36 from which the recording medium P has been separated by curvature is removed by the intermediate transfer body cleaning device 190A. An example of the glossy toner image is a solid glossy toner image.

[0405] Furthermore, the patch image toner on the secondary transfer member 37A is cleaned by a cleaning blade 71 of the secondary transfer device . [Example]

[0406] The present invention will be specifically explained below with reference to examples, but the present invention is not limited to these examples. In the examples, the units "parts" and "%" are used, but unless otherwise specified, The units are expressed as "parts by mass" or "% by mass".

[0407] A. Preparation of Toner 1 and Developer [1] (A.1) Preparation of amorphous polyester particle dispersion [A1] The following polyhydric alcohol monomer and polycarboxylic acid monomer were placed in a four-neck flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple, and heated to 170°C to dissolve them, thereby preparing a mixed solution 1 of polyhydric alcohol and polycarboxylic acid. <Polyhydric alcohol> Bisphenol A ethylene oxide 2 mole adduct 7 mole parts Bisphenol A propylene oxide 2 mole adduct 15 mole parts Ethylene glycol 32 molar parts Pentanediol 46 parts by mole <Polycarboxylic acid> Terephthalic acid 55 parts by mole Fumaric acid 5 mole parts Dodecenyl succinic acid 40 mole parts

[0408] While stirring, 0.003.0 mass% of Ti(OBu)4 was added as an esterification catalyst based on the total amount of polycarboxylic acid components, and the mixture was heated to 235°C and reacted at normal pressure (101.3 kPa) for 5 hours and then under reduced pressure (8 kPa) for 1 hour. The mixture was then cooled to 200°C and reacted under reduced pressure (20 kPa), after which the solvent was removed to produce amorphous polyester [a1].

[0409] 108 parts by mass of the prepared amorphous polyester [a1] and 64 parts by mass of methyl ethyl ketone were stirred at 70° C. for 30 minutes to dissolve them, thereby preparing solution 1.

[0410] Next, an aqueous solution prepared by dissolving sodium polyoxyethylene lauryl ether sulfate in 26 parts by mass of ion-exchanged water to a concentration of 1% by mass was added to this solution 1. Next, 3.4 parts by mass of a 25% by mass aqueous sodium hydroxide solution was added to prepare solution 2.

[0411] This solution 2 was placed in a reaction vessel equipped with a stirrer, and while stirring with the stirrer, 270 parts by mass of ion-exchanged water heated to 70°C was added dropwise over a period of 70 minutes. During the dropwise addition, solution 2 in the reaction vessel became cloudy. After the entire amount of solution 2 was added dropwise, solution 2 became emulsion 1 in a uniformly emulsified state.

[0412] The volume average particle size of the oil droplets in this emulsion 1 was measured using a laser diffraction particle size distribution analyzer "LA-750 (manufactured by HORIBA)" and was found to be 90 nm.

[0413] Next, while keeping this emulsion 1 at 70°C, the emulsion was stirred for 1 hour under a reduced pressure of 15 kPa (150 mbar) using a diaphragm vacuum pump "V-700" (manufactured by BUCHI) to distill off the methyl ethyl ketone.

[0414] In this way, an amorphous polyester particle dispersion liquid [A1] in which fine particles of the amorphous polyester [a1] were dispersed was prepared.

[0415] The solid content of the prepared amorphous polyester particle dispersion [A1] was 24%. The volume average particle size of the amorphous polyester [a1] fine particles in the amorphous polyester particle dispersion [A1] was measured using the laser diffraction particle size distribution analyzer and found to be 103 nm.

[0416] (A.2) Preparation of crystalline polyester particle dispersion [C1] The following polyhydric alcohol monomer and polycarboxylic acid monomer were placed in a four-neck flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple, and heated to 170°C to dissolve, thereby preparing a mixed solution 2 of polyhydric alcohol and polycarboxylic acid. <Polycarboxylic acid> Sebacic acid 60 mole parts <Polyhydric alcohol> 1,6-Hexanediol 40 parts by mole

[0417] Next, the above mixed solution 2 was placed in a reaction vessel equipped with a stirrer, a thermometer, a condenser, and a nitrogen gas inlet tube, and the atmosphere in the reaction vessel was replaced with dry nitrogen gas. Thereafter, 0.003 mass% of Ti(OBu)4 was added to the reaction vessel based on the total amount of polycarboxylic acid components, and the temperature was raised to 235°C. The reaction was carried out at normal pressure (101.3 kPa) for 5 hours and then under reduced pressure (8 kPa) for 1 hour to prepare reaction solution 1.

[0418] Next, the prepared reaction liquid 1 was cooled to 200° C., and then reacted under reduced pressure (20 kPa) for 1 hour to produce a crystalline polyester [c1].

[0419] 174 parts by mass of the prepared crystalline polyester [c1] was added to 102 parts by mass of methyl ethyl ketone, and the mixture was stirred at 75° C. for 30 minutes to dissolve, thereby preparing solution 3.

[0420] Next, an aqueous solution prepared by dissolving sodium polyoxyethylene lauryl ether sulfate in 26 parts by mass of ion-exchanged water to a concentration of 1% by mass was added to this solution 3. Next, 4.6 parts by mass of a 25% by mass aqueous sodium hydroxide solution was added to prepare solution 4.

[0421] This solution 4 was placed in a reaction vessel equipped with a stirrer, and 375 parts by mass of water heated to 70°C was added dropwise to the solution 4 over a period of 70 minutes while stirring. During the addition, the solution 4 in the reaction vessel became cloudy, and after the entire amount of solution 4 was added dropwise, it became emulsion 2 in a uniformly emulsified state.

[0422] Next, while keeping this emulsion 2 at 70°C, the emulsion was stirred for 1 hour under a reduced pressure of 15 kPa (150 mbar) using a diaphragm vacuum pump "V-700" (manufactured by BUCHI) to distill off the methyl ethyl ketone.

[0423] Thereafter, the mixture was cooled at a cooling rate of 6° C. / min to prepare a crystalline polyester particle dispersion liquid [C1] in which fine particles of the crystalline resin [c1] were dispersed.

[0424] The solid content of the prepared crystalline polyester particle dispersion [C1] was 25%. As a result of measurement using a particle size distribution analyzer, the volume average particle size of the crystalline polyester [c1] in the crystalline polyester particle dispersion [C1] was 191 nm.

[0425] (A.3) Preparation of glitter pigment dispersion [P1] (Preparation of photoluminescent pigment) 200 parts of aluminum pigment "2173EA" manufactured by Showa Aluminum Powder Co., Ltd. was washed five times with 1,000 parts of isopropyl alcohol manufactured by Kanto Chemical Co., Ltd., dried, and then mechanically pulverized and classified. By adjusting the pulverization and classification processes, a bright pigment with the desired major axis diameter can be obtained. This procedure produced bright pigment [p1] with the desired major axis diameter.

[0426] (Preparation of glitter pigment dispersion [P1]) The prepared bright pigment, surfactant, and ion-exchanged water were mixed in the amounts shown below and then sent to the Pacific Ocean. The mixture was dispersed for about an hour using a Cavitron "CR1010" emulsifying and dispersing machine manufactured by Kogyo Co., Ltd. Photochromic pigment [p1] 100.0 parts by mass (solid content) Anionic surfactant "Neogen RK" (registered trademark) 1.5 parts by mass Ion-exchanged water 400 parts by mass

[0427] This resulted in the preparation of a bright pigment dispersion liquid [P1] containing bright pigment particles dispersed therein. The bright pigment dispersion liquid [P1] had a solids concentration of 20 mass % and a major axis diameter of the resulting pigment of 10 μm.

[0428] The average major axis diameter of the bright pigment was measured by the following method.

[0429] An electron micrograph was obtained using a scanning electron microscope (SEM), for example, "JSM-7401F" (manufactured by JEOL Ltd.) In the electron micrograph, the major axis diameter was measured, and the number-average major axis diameter for 1,000 bright pigment particles was calculated.

[0430] (A.4) Preparation of release agent particle dispersion [W1] The release agent, surfactant, and ion-exchanged water shown below were heated to 110°C and dispersed using an IKA homogenizer "Ultra Turrax T50," and then dispersed using a Gaulin high-pressure homogenizer. Release agent [wa] 20 parts by mass Release agent [wb] 33 parts by mass Anionic surfactant "Neogen RK" (registered trademark) 5 parts by mass Ion-exchanged water 200 parts by mass

[0431] The release agent [wa] is a high-purity refined paraffin (hydrocarbon-based) wax "HNP-9" manufactured by Nippon Seiro Co., Ltd., and the release agent [wb] is behenyl behenate (ester-based). The anionic surfactant "Neogen RK" is manufactured by Daiichi Kogyo Seiyaku Co., Ltd. ("Neogen" is a registered trademark of the company).

[0432] In this way, a release agent particle dispersion liquid [W1] (release agent concentration: 24% by mass) was prepared in which a release agent having an average particle size of 0.20 μm was dispersed.

[0433] The volume average particle diameter of the particles in the release agent fine particle dispersion [W1] was measured using a Microtrac UPA-150 (manufactured by Nikkiso Co., Ltd.) and was found to be 202 nm.

[0434] (A.5) Preparation of toner base particles [1] The following dispersion and surfactant were placed in the amounts shown below in a 2 L cylindrical stainless steel vessel (reaction vessel), and dispersed and mixed for 10 minutes using an IKA homogenizer "Ultra Turrax T50" at a rotation speed of 4000 rpm while applying shear force, to prepare mixed liquid 3 of the following dispersion and surfactant. Amorphous polyester particle dispersion [A1] 350 parts by mass Crystalline polyester particle dispersion [C1] 100 parts by mass Bright pigment dispersion [P1] 150 parts by mass Release agent particle dispersion liquid [W1] 66 parts by mass Anionic surfactant "Dowfax 2A1" 2.8 parts by mass

[0435] The anionic surfactant used was "Dowfax 2A1" (manufactured by The Dow Chemical Company). "Dowfax 2A1" was diluted and used as a 20% aqueous solution.

[0436] Thereafter, 100.0 parts by mass of a 2% by mass aqueous solution of aluminum sulfate was gradually added as a flocculant to the mixed solution 3 over 30 minutes. After the dropwise addition was completed, the homogenizer rotation speed was set to 5000 rpm, and the mixture was stirred for 10 minutes to thoroughly mix the mixed solution 3 and the flocculant in the reaction vessel, thereby preparing raw material dispersion liquid 1.

[0437] Thereafter, a stirrer and a mantle heater were installed in the reaction vessel, and the growth of aggregated particles in raw dispersion liquid 1 was promoted at 54°C while adjusting the rotation speed of the stirrer so that the slurry was sufficiently stirred.

[0438] At this time, the pH of the raw dispersion liquid 1 was adjusted to within the range of 2.2 to 3.5 with 0.3 mol / L nitric acid and 1.0 mol / L aqueous sodium hydroxide solution.

[0439] Next, the temperature of raw material dispersion 1 was raised to 56°C, and while the size and shape of the particles in the raw material dispersion were confirmed using an optical microscope and a Multisizer II, a mixture of the following components, which had been mixed in advance, was added to raw material dispersion 1 over a period of 20 minutes. <Ingredients> Amorphous polyester particle dispersion [A1] 150 parts by mass Anionic surfactant 15 parts by mass

[0440] The anionic surfactant used in the above-mentioned components was "Dowfax 2A1" (manufactured by The Dow Chemical Company). "Dowfax 2A1" was diluted and used as a 20% aqueous solution.

[0441] Next, after maintaining the temperature at 50°C for 30 minutes, the following components were added to the reaction vessel, and then a 1 mol / L aqueous sodium hydroxide solution was added to adjust the pH of the raw material dispersion to 9.0. <Ingredients> 20% by weight EDTA (ethylenediaminetetraacetic acid) aqueous solution 8.0 parts by weight

[0442] Thereafter, the temperature was increased to 80°C at a rate of 1°C / min while adjusting the pH to 9.0 every 5°C, and then maintained at 80°C.

[0443] After confirming the fusion of the aggregated particles with an optical microscope, the pH was lowered to 6.0 while maintaining the temperature at 80°C. After 1 hour, heating was stopped and the mixture was cooled at a rate of 10.0°C / min.

[0444] The resulting toner particles were then sieved through a 40 μm mesh, washed repeatedly with water, and dried in a vacuum dryer to produce toner base particles [1]. The volume average particle size of the produced toner base particles was 10.6 μm. The average circularity, measured using a particle size analyzer (Malvern Instruments, FPIA-3000), was 0.972.

[0445] (A.6) Preparation of external additives (Preparation of silica particles [S1]) Mixture 4 was prepared by adding 945 parts by mass of methanol, 45 parts by mass of 28% aqueous ammonia, and 135 parts by mass of water to a 3-liter reactor equipped with a stirrer, a dropping funnel, and a thermometer and mixing them.

[0446] The temperature of this mixed solution 4 was adjusted to 35°C, and 405 parts by mass of tetramethoxysilane was added dropwise over 6 hours while stirring. After the addition, stirring was continued for another hour to carry out hydrolysis, resulting in a suspension of silica particles. This suspension was distilled under reduced pressure and dried to obtain fine particles, which were then crushed to produce silica particles [S1]. The number-average particle size of the silica particles [S1] was 40 nm.

[0447] The number-average particle size of the silica particles [S1] was determined by using a scanning electron microscope (SEM) (JEM-7401F, manufactured by JEOL Ltd.) to capture an SEM photograph enlarged 50,000 times with a scanner, binarizing the external additive particles in the SEM photograph with an image processing analyzer (LUZEX AP, manufactured by Nireco Corporation), and calculating the Feret's diameter in the horizontal direction for 100 external additive particles.

[0448] (A.7) Addition of external additives and mixing with carrier Toner 1 was prepared by adding 1.5 parts by mass of silica particles [S1] as an external additive to 100 parts by mass of toner base particles [1] and mixing them in a Henschel mixer (manufactured by Nippon Coke and Engineering Co., Ltd.) at a rotor peripheral speed of 30 m / s and 30°C for 5 minutes.

[0449] Thereafter, toner 1 from which coarse particles were removed using a sieve with 45 μm openings and ferrite carrier with a volume average particle size of 32 μm coated with acrylic resin were added and mixed so that the toner particle concentration was 8 mass %.

[0450] In this way, developer [1] was prepared.

[0451] B. Preparation of Toners 2 to 17 and Developers [2] to

[17] (B.1) Preparation of amorphous polyester particle dispersions [A2] to [A4] In preparing the amorphous polyester particle dispersion liquid used to prepare the toner base particles [2] to

[17] , the type and amount of the polyhydric alcohol monomer were changed as shown in Table I. The same procedures were followed as for the amorphous polyester particle dispersion liquid [A1]. In this way, amorphous polyester particle dispersion liquids [A2] to [A4] were prepared. The toner base particles used to prepare toners 2 to 17 and developers [2] to

[17] are referred to as toner base particles [2] to

[17] .

[0452] [Table 1]

[0453] (B.2) Preparation of a dispersion of crystalline polyester particles, a luster pigment, and release agent particles The crystalline polyester particle dispersion liquid and the luster pigment dispersion liquid used in producing the toner base particles [2] to

[17] were the same as those used in producing Toner 1, i.e., the crystalline polyester particle dispersion liquid [C1] and the luster pigment dispersion liquid [P1].

[0454] For the release agent particle dispersion liquid used in the preparation of toner base particles [2] to

[17] , the same release agent as in the release agent particle dispersion liquid [W1] used in the preparation of toner 1 was used, but the amount of release agent was the amount shown in Table II.

[0455] (B.3) Preparation of toner base particles [2] to

[17] The types and amounts of the amorphous polyester particle dispersion [A1], crystalline polyester particle dispersion [C1], luster pigment dispersion [P1], and release agent particle dispersion [W1] were changed as shown in Table II. Otherwise, toner base particles [2] to

[17] were prepared in the same manner as toner base particles [1].

[0456] (B.4) Preparation of external additives The external additives used in producing toners 2 to 17 and developers [2] to

[17] were the same as the silica particles [S1] used in producing toner 1.

[0457] (B.5) Adding external additives and mixing with carrier Toners 2 to 17 and developers [2] to

[17] were prepared in the same manner as in the preparation of developer [1], except that toner base particles [1] were replaced with toner base particles [2] to

[17] .

[0458] C. Analysis of resin composition in each toner The measurement and analysis of the structure derived from the polyhydric alcohol in the amorphous polyester in the prepared toners 1 to 17 were carried out by decomposing each toner matrix particle after removing the external additives from each toner by alkaline hydrolysis at a certain temperature and then measuring and analyzing by nuclear magnetic resonance (NMR). The results are shown in Table II.

[0459] (Analysis method of resin composition) The composition of each resin contained in the toner matrix particles was analyzed by thermal decomposition gas chromatography-mass spectrometry (GC / MS: Gas Chromatography / Mass Spectrometry) method. Specifically, it can be quantified by the standard addition method using a column and a detector that can confirm the detection of monomers having a specific structure.

[0460] An example of the detailed thermal decomposition conditions and GC / MS measurement conditions is shown below. <Thermal decomposition conditions> Measuring device: PY-2020iD (manufactured by Frontier Lab Co., Ltd.) Measured mass: 0.1 mg Heating temperature: 550 °C Heating time: 0.5 minutes <GC / MS measurement conditions> Measuring device: QP2010 (manufactured by Shimadzu Corporation) Column: UltraALLOY-5 (inner diameter: 0.25 mm, length: 30 m, thickness: 0.25 μm, manufactured by Frontier Lab Co., Ltd.) Temperature rising range: 40 °C to 320 °C (held at 320 °C) Temperature rising rate: 20 °C / min

[0461] D. Evaluation [1] Laminate adhesion Developers [1] to

[17] were loaded sequentially into a modified developing device, and image formation was carried out under the following environmental conditions of 20°C and 55% RH under Conditions 1 and 2. The developing device used was a commercially available color multifunction printer "bizhub PRO C6500 (manufactured by Konica Minolta)" modified to allow for flexible setting of the fixing temperature, toner adhesion amount, and system speed. Regarding the positional relationship between the upper heating and pressure member FR1 and the lower heating and pressure member FR2 under Conditions 1 and 2, see Figure 1.

[0462] <Condition 1> Paper type: A4 size NPI 64.0 g / m 2 (Nippon Paper Industries) Adhesion amount: 8g / m 2 Fixing temperature: Temperature of the upper heating and pressure member FR1: the above minimum fixing temperature + 20°C Temperature of the lower heating and pressure member FR2: Temperature of the upper heating and pressure member -20°C Line speed: 300mm / s <Condition 2> Paper type: A4 size mirror coated platinum paper 256 g / m 2 (Oji Paper Co., Ltd.) Adhesion amount: 8g / m 2 Fixing temperature: Temperature of the upper heating and pressure member: Minimum fixing temperature above + 50°C Temperature of the lower heating and pressure member: Temperature of the upper heating and pressure member -20°C Line speed: 200mm / s

[0463] Next, the images were laminated on the two types of paper on which the images were created under the above conditions 1 and 2 under the following lamination conditions, and left in an environment of normal temperature and humidity of 20°C and 55% RH for 7 days.

[0464] <Lamination conditions> Equipment: 4-roller laminator "L3250" (Asuka Co., Ltd.) Speed: Speed ​​“3” Laminator film: 100 μm thick, A4 size Asmix laminator film

[0465] The side of the laminate image was then dropped six times from a height of 20 cm, and the presence or absence of peeling between the laminate material and the image was visually inspected according to the following criteria. The laminate adhesion was evaluated simultaneously for both the samples formed under Condition 1 and Condition 2. A and B were used as the pass criteria.

[0466] (Evaluation criteria) A: There is no area where the toner or laminating material has peeled off from the transfer paper. B: In only one place, the toner and laminating material have peeled off from the transfer paper. D: There are multiple areas where the toner and laminating material have peeled off from the transfer paper.

[0467] [2] Varnish application On the image formed when evaluating the lamination adhesion, varnish "UV VECTA Coat Varnish PC-3KW2" manufactured by T&K Corporation was applied to a thickness of 5 μm using a bar coater.

[0468] After that, a high-pressure mercury lamp is used to illuminate the image, with an integrated light intensity of 120-130mJ / cm 2 The varnish was cured by irradiating it with ultraviolet light so that a layer of varnish was formed on the image formed when evaluating the laminate adhesion.

[0469] The varnish used contained a polymerizable monomer for varnish having a polymerizable functional group containing an ethylenic double bond and a photopolymerization initiator (radical polymerization initiator).

[0470] The surface of the varnish layer on the obtained image was visually inspected to see if the varnish was clearly repelled, and if it was not repelled, the number of pinholes within a 10 cm x 10 cm area was counted.

[0471] Based on these results, the varnish application properties of the samples formed under Condition 1 and those formed under Condition 2 were evaluated together using the following evaluation criteria. According to the following evaluation criteria, A, B, and C were used as the pass criteria.

[0472] (Evaluation criteria) A: No pinholes were found within a 10cm x 10cm area. B: There were one to two tiny pinholes in a 10cm x 10cm area. C: There were 3 to 10 tiny pinholes in a 10cm x 10cm area. D: 11 or more pinholes or cracks in a 10cm x 10cm area

[0473] [3] Brightness For each image formed under Condition 1 and Condition 2 in the evaluation of lamination adhesion, the lightness L* in the L*a*b* color system was measured using a goniophotometer (GP-200) at an incident angle of 60 degrees and a reflection angle of 60 degrees. * The average value of the brightness of the samples formed under condition 1 and the samples formed under condition 2 is shown in .

[0474] (Evaluation criteria) A: Lightness L* is 300 or more. D: Lightness L* is less than 300.

[0475] [Table 2]

[0476] [4] Overall Review As is apparent from the description of the toners prepared in the above examples and Tables I and II, The evaluation results of the Examples are generally superior to those of the Comparative Examples. Furthermore, it can be seen that the images formed using the toners used in the Examples, which have excellent low-temperature fixing properties and hot offset resistance, have relatively high fixed image brightness and are excellent in post-processability.

[0477] While embodiments of the present invention have been described and illustrated in detail above, the disclosed embodiments are made for purposes of illustration and example only, and not limitation, and the scope of the invention should be construed in terms of the appended claims. [Explanation of symbols]

[0478] 1. Photoluminescent pigments 2 Resin part 3. Release agent 10 Toner base particles 31 Photosensitive drum 32 Charger 33 Exposure Engineering 34 Developing device 36 Intermediate transfer body 37 Primary transfer roller 37A Secondary transfer member 47 Fixing device 70 Secondary transfer device 71 Cleaning blade 100 process units 110 Container 112 Raw material input port 117 Jacket 118 Horizontal Rotating Body 119 Vertical Rotating Body 120 Outlet 122 Motor 190 Photoconductor cleaning device 190A Intermediate transfer body cleaning device P Recording medium FR1 Upper fixing roller (upper heating and pressure member) FR2 lower fixing roller (lower heating and pressure member) LI Incident light on toner base particles LR: Light reflected by the photoluminescent pigment in the toner base particles L: Longest particle diameter of the photoluminescent pigment (maximum length of the photoluminescent pigment) La Average long axis particle diameter of photoluminescent pigment W: Minor axis particle diameter of the bright pigment (maximum length in the direction intersecting with the major axis particle diameter L) Wa Average minor axis particle diameter of the brilliant pigment H Thickness of the bright pigment (minimum length in the direction perpendicular to the major axis particle diameter L) Ha Average thickness of the glitter pigment BP: Defective area where reflected light is scattered and reflection efficiency is reduced GS image forming device SC Image Reader

Claims

1. A toner for developing electrostatic images, comprising a photoluminescent pigment and toner base particles containing the photoluminescent pigment, the toner base particles contain a release agent and an amorphous polyester, The amorphous polyester is a polycondensation product of a polycarboxylic acid and a polyhydric alcohol, and the amorphous polyester has a structural unit derived from bisphenol A or a bisphenol A derivative, The content of structural units derived from bisphenol A or bisphenol A derivatives in the amorphous polyester is less than 50 mol % based on the structural units derived from polyhydric alcohols.

1. A toner for developing electrostatic images, comprising:

2. The average major axis diameter of the bright pigment is in the range of 3 to 30 μm.

2. The toner for developing electrostatic images according to claim 1.

3. The release agent has a hydrocarbon-derived structural unit or a hydrocarbon-derived structural unit and an ester-derived structural unit, and The content of the hydrocarbon-derived structural unit in the release agent is within a range of 3.0 to 10.0% by mass relative to the toner base particles.

2. The toner for developing electrostatic images according to claim 1.

4. The release agent has a hydrocarbon-derived structural unit and an ester-derived structural unit.

2. The toner for developing electrostatic images according to claim 1.

5. The bright pigment is aluminum.

2. The toner for developing electrostatic images according to claim 1.

6. The toner for developing electrostatic images according to claim 1 is used. An image forming method comprising:

Images