JP2012194453A - Transparent toner for electrophotographic development, image forming method and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent toner for electrophotographic development, an image forming method and a process cartridge, achieving excellent low-temperature fixability as well as hot offset resistance and storage stability, and allowing formation of a fine, high-gloss image.SOLUTION: The transparent toner contains, as a toner composition, a binder resin, a crystalline polyester resin and a lubricant. The toner shows a peak value of dielectric loss tangent present in the range from 80 to 160°C obtained by viscoelasticity evaluation of the toner and calculated by formula (1):(loss modulus (G"))/(storage modulus (G'))=(dielectric loss tangent (tanδ)), with a peak value of the dielectric loss tangent of 3 or more, and has a storage modulus (G') shown in formula (1) of 1 Pa or more and 1×10Pa or less at a temperature of 120 to 160°C. An image is formed by an electrophotographic process on a recording medium.

Description

  The present invention relates to a transparent toner for electrophotographic development used in an electrophotographic process such as a copying machine, a laser printer, or a facsimile, an image forming method, and a process cartridge.

  The electrophotographic method used in an image forming apparatus such as a laser printer or a dry electrostatic copying machine uniformly charges the surface of an image carrier such as a photoconductive layer, and then exposes and exposes the surface of the image carrier. The latent image is dissipated to form an electrical latent image, which is further visualized by attaching a fine powder having a charge called toner to the latent image, and the resulting visible image is transferred to transfer paper. And the like, followed by permanent fixing by heating, pressurizing and the like, and cleaning of fine powder remaining on the surface of the image carrier without being transferred.

  In recent image forming apparatuses, there are increasing demands for energy saving at the time of toner fixing and image forming apparatuses capable of processing at high speed, and the toner itself is required to have a property of melting at a low temperature. In the case where low temperature fixing is possible in the toner characteristics, the melting of the toner is promoted. Therefore, the transparent toner requiring high gloss is particularly preferable because of not only the energy saving viewpoint but also the advantage for the final image quality. However, if the melting point of the toner is simply lowered to enable low-temperature fixing, the storage stability of the toner and the adhesion to the carrier surface when agitated with the carrier in the two-component developing device (hereinafter also referred to as “spent”) There is a concern about deterioration of the charge imparting ability of the carrier.

  Further, in recent image forming apparatuses, there is a great demand for high image quality, and in response to a request for an image such as a photographic image, a clear high-gloss image can be obtained by imparting gloss to the surface of a recording medium such as recording paper. It is known that can be provided. For example, the transparent toner is disposed in a non-image portion having no chromatic color toner, thereby eliminating the difference in gloss from the portion with the chromatic color toner on the recording medium, or the transparent toner on the entire surface of the recording medium. The method etc. which arrange | position is used (refer patent document 1, patent document 2, patent document 3). In addition, an image forming apparatus in which a fixing processing system capable of selecting a glossy or non-glossy image is compactly arranged on-line has been proposed. For example, a recording medium on which a chromatic color toner and a transparent toner image are formed is recorded on the fixing apparatus. Describes that the entire surface of the recording medium is made a high-gloss image by heating and melting and cooling peeling (see Patent Document 4). According to the methods disclosed in Patent Documents 1 to 4, it is possible to eliminate the gloss difference on the entire surface of the recording medium and provide uniform gloss.

On the other hand, in the printing field, as a method for controlling the gloss of a recording medium, UV varnish printing, varnishing, PP pasting, and the like are generally performed, and so-called spot varnish that makes a specific portion highly glossy is performed. In this case, after normal color printing, a plate for making it partially glossy is prepared, and spot printing is performed using UV varnish or the like. According to this method, the spot varnished part can obtain high gloss like a photograph, the part not spot varnished has a low gloss, the gloss difference on the image is large, and it is different from normal printing. I can plan.
However, in order to do this in offset printing, it is necessary to prepare a dedicated plate and cannot handle variable data, so a certain number of printing lots is required. On the other hand, if a spot printing function similar to the above can be realized by electrophotography used in image forming apparatuses such as laser printers and dry electrostatic copying machines, a printing plate is not necessary and variable data can be handled. it can.

As a method of forming different glossiness on the same recording medium by the electrophotographic method, a method of controlling the glossiness by the number average molecular weight of the resin used for the toner (see Patent Document 5), a transparent method after fixing the colored toner, A method of forming a toner image and lowering the gloss by lowering the fixing temperature (see Patent Document 6), or a method of printing and fixing the gloss range at the first time, and printing and fixing the non-gloss range at the second time (patent) Reference 7) is disclosed. However, according to these methods, it is possible to obtain different glossiness on the same recording medium, but high spot glossiness close to photographic glossiness as in the spot varnish has not yet been realized.
In order to solve this problem, for example, as described in Patent Document 8, it has been proposed to add a specific non-olefin crystalline polymer having a sharp melt property at a glass transition temperature in a binder resin. ing. For example, as described in Patent Document 9, it has been proposed to use crystalline polyester.

  Patent Document 10 discloses a method for improving the image quality of a two-component developer by defining the average particle size, particle size distribution, carrier fluidity, and developer fluidity of the toner. However, since it is essential that the toner used in this method contains non-magnetic colorant-containing resin particles, this method is limited to colored toner, and image formation using transparent toner as in this case Not applicable to

  The present invention has been made in view of the above-described prior art, and has both excellent excellent low-temperature fixability, high hot offset resistance, and good storage stability (storage stability), and is fine and high. An object of the present invention is to provide a transparent toner for electrophotographic development capable of forming a glossy image, an image forming method, and a process cartridge.

  As a result of intensive studies, the present inventors have found that the above problems can be solved by the inventions described in the following [1] to [13], and have reached the present invention. Hereinafter, the present invention will be specifically described.

[1]: The above problem is a transparent toner for electrophotographic development used for forming a transparent toner image on a recording medium,
The toner includes a binder resin, a crystalline polyester resin, and a lubricant as a component of the toner, and a peak value of tangent loss obtained by evaluating viscoelasticity of the toner and calculated by the following formula (1) is 80 to 160 [ ° C], the peak value of the tangent loss is 3 or more, and the storage elastic modulus (G ′) shown in the formula (1) is 1 [Pa] or more at 120 to 160 [° C], This is solved by a transparent toner for electrophotographic development, which is 1 × 10 ⁴ [Pa] or less.
Loss modulus (G ″) / Storage modulus (G ′) = tangent loss (tan δ) (1)

  [2]: In the transparent toner for electrophotographic development according to the above [1], the weight average particle size (Mw) of the transparent toner is 3 to 8 μm, and the ratio of particles of 4 μm or less is 10 in the particle size distribution. The ratio of particles of ˜70% by number and 8 μm or more is 1 to 20% by volume, and the ratio of particles of 10.08 μm or more is 6% by volume or less.

[3]: In the transparent toner for electrophotographic development according to the above [1] or [2], the value of the storage elastic modulus (G ′) is 1 × 10 ⁵ [Pa] or more at 70 to 90 ° C. It is characterized by being.

  [4]: In the transparent toner for electrophotographic development according to any one of [1] to [3], the lubricant is a higher aliphatic alcohol / higher fatty acid lubricant, a fatty acid amide lubricant, an aliphatic hydrocarbon It contains at least one selected from a lubricant, a metal soap lubricant, and a fatty acid ester lubricant.

  [5]: The transparent toner for electrophotographic development according to any one of [1] to [4], wherein the lubricant includes a higher aliphatic alcohol / higher fatty acid-based lubricant.

  [6]: The transparent toner for electrophotographic development according to any one of [1] to [4], wherein the lubricant includes a fatty acid amide-based lubricant.

  [7]: The transparent toner for electrophotographic development according to [6] above, wherein the fatty acid amide-based lubricant is contained at least in the toner.

  [8]: The transparent toner for electrophotographic development described in [6] or [7] above, wherein the fatty acid amide lubricant is N, N′-ethylene-bisstearic acid amide.

  [9]: The above-described problem is obtained by charging at least the surface of the image carrier and an electrostatic latent image formed on the charged image carrier, according to any one of [1] to [7]. Developing with a developing transparent toner, transferring the transparent toner image formed on the image carrier onto a recording medium, and fixing the transparent toner image transferred onto the recording medium with a fixing member And an image forming method characterized by including a fixing step.

  [10] In the electrophotographic image forming method described in [9] above, a step of forming a color image using one or more kinds of chromatic toner on the recording medium, and the transparent toner for electrophotographic development is used. And a step of forming a transparent toner image.

  [11]: In the electrophotographic image forming method described in [9] or [10] above, the layer thickness of the transparent toner image after the fixing is 1 to 15 μm.

  [12]: In the electrophotographic image forming method according to any one of [9] to [11], at least one layer of the transparent toner image is formed on the outermost surface of the recording medium on which the image is fixed. It is characterized by being.

  [13]: The above-described problem includes at least an image carrier and a developing unit that converts at least the electrostatic latent image formed on the image carrier into a visible image using a toner or a developer composed of a toner and a carrier. Further, the invention is solved by a process cartridge which is detachably provided in the main body of the image forming apparatus and the toner is the transparent toner for electrophotographic development described in any one of [1] to [8]. .

  According to the present invention, excellent low-temperature fixability, high hot offset resistance and storage stability (storage stability) are compatible, and a fine and high gloss (high gloss) image can be formed. A transparent toner for electrophotographic development, an image forming method using the transparent toner, and a process cartridge can be provided.

It is a figure for demonstrating the preferable example (it has a peak value in 80-160 degreeC) which has a peak in the tangent loss obtained by viscoelasticity (G ', G ") evaluation. FIG. 6 is a schematic diagram illustrating a state in which toner is fixed directly on paper. FIG. 6 is a schematic diagram illustrating a state where the surface of the transparent toner fixed on the chromatic toner layer is not smooth and high gloss is not obtained. FIG. 6 is a schematic diagram showing a state where the surface is smooth and high gloss is obtained when a transparent toner having a tangent loss (tan δ) peak value of 3 or more is fixed on a chromatic toner layer. It is a schematic block diagram which shows an example of the electrophotographic developing apparatus used by this invention. It is the schematic which shows an example of the image development apparatus used by this invention. It is a schematic block diagram which shows an example of the image forming apparatus which has the image development apparatus of FIG. It is a schematic block diagram which shows the other example of the image forming apparatus used by this invention. It is a schematic block diagram which shows an example of the process cartridge used by this invention.

The present invention is described in further detail below.
When the low-temperature fixability is enhanced, the transparent toner not only has the effect of energy saving, but also can be made more glossy because sufficient melting can be obtained in the fixing step. Glossiness is the most important purpose of using a transparent toner, and is the most important role of the transparent toner. However, increasing the low-temperature fixability tends to impair the storage stability (storage stability) of the toner as a side effect, and the compatibility between the low-temperature fixing of the transparent toner and the storage stability is a development system using a transparent toner. It was a problem.
In particular, transparent toner differs from yellow, magenta, cyan, and black toners commonly used in full-color electrophotographic development, and development units (additional units) equipped with toners of colors other than the above-mentioned colorants (three primary colors), as needed It is often used while being replaced. In such a usage situation, it is assumed that the user's management is difficult to reach while another color toner is used as the fifth color. Therefore, the storage stability of the transparent toner is required to have a higher function than that of other colorants (three primary colors).

The present inventors have intensively studied to solve the above problems. As a result, the composition of the transparent toner for electrophotographic development used for forming a transparent toner image on the recording medium contains a binder resin, a crystalline polyester resin and a lubricant, and the viscoelasticity of the toner is evaluated. The tangent loss peak value obtained by the following equation (1) is in the range of 80 to 160 [° C.], the tangent loss peak value is 3 or more, and the storage shown in equation (1) Since the value of the elastic modulus (G ′) is 1 [Pa] or more and 1 × 10 ⁴ [Pa] or less at 120 to 160 [° C.], extremely excellent low-temperature fixability and hot offset resistance, storage Newly provided is a transparent toner (abbreviated as “transparent toner” or “toner”) for electrophotographic development that achieves both stability (storability) and achieves high gloss even in low-temperature fixing. Findings were obtained.
Loss modulus (G ″) / Storage modulus (G ′) = tangent loss (tan δ) (1)

That is, the transparent toner of the present invention has a tangent loss (tan δ) [peak temperature: 80 to 160 ° C., peak value: 3 or more] obtained by viscoelasticity evaluation and calculated by the above formula (1), storage elastic modulus (G ′) There is a specified value in [1 to 1 × 10 ⁴ Pa or less at 120 to 160 ° C.], and the reason will be described below.

In order to fix the transparent toner at a low temperature and ensure high glossiness, it is necessary to have a characteristic that the storage elasticity (G ′) suddenly decreases at a relatively low temperature. If the storage elastic modulus (G ′) of the toner at the time of fixing can be lowered, the molten toner can easily enter the recording paper with a low surface smoothness and the minute unevenness of the chromatic toner, and the relative viscosity is relatively high in the viscoelasticity. In particular, the plastic component becomes high, and it becomes difficult to restore the shape of the toner particles after pressure fixing. Therefore, the spreadability is excellent, the smoothness of the toner layer surface is increased, and a high glossiness can be obtained.
On the other hand, from the viewpoint of hot offset resistance, it is important that the storage elastic modulus (G ′) has a characteristic of trying to maintain the viscosity, since the slope of the decrease becomes gentle after reaching a predetermined viscosity. Further, the loss elastic modulus (G ″) needs not to cause a rapid decrease like the storage elastic modulus (G ′).

As described above, the peak of tangent loss as shown in FIG. 1 does not appear unless the storage elastic modulus (G ′) rapidly decreases from a predetermined temperature and the inclination of the decrease does not become gentle in the predetermined temperature range. Only the toner having such characteristics has a peak of tangent loss, and the temperature of the maximum peak is preferably expressed at 80 to 160 ° C.
When the maximum peak temperature of the tangent loss is lower than 80 ° C., the storage elastic modulus (G ′) is lowered in the storage environment and the storage stability (storage stability) as the toner is deteriorated, and the toner aggregates in the storage environment. Resulting in. Moreover, the viscoelasticity at high temperature becomes too low, and the hot offset resistance is impaired. When the maximum peak temperature of the tangent loss exceeds 160 ° C., the function of fixing at a low temperature is impaired and the intended problem cannot be achieved.

Further, when the maximum value of the tangent loss is small, the storage elastic modulus (G ′) does not decrease as compared with the loss elastic modulus (G ″), and preferable low-temperature fixability, hot offset resistance, and high gloss can be achieved simultaneously. In particular, when gloss is imparted to a recording medium with a transparent toner, it is important that the tangent loss is 3 or more for the following reason.
In order to increase the glossiness of the toner layer surface, it is necessary to make the outermost surface of the toner layer as smooth as possible. For this purpose, as described above, it is important to reduce the storage elastic modulus (G ′) and increase the spreadability of the toner layer that forms the outermost surface. The compatibility with the surface holding the toner layer is also an important factor.

In the case of image formation with chromatic toner, the toner layer is formed on paper. In that case, even when the ratio of the storage elastic modulus (G ′) of the toner is relatively high, the paper plasticity serves as a cushion for the elasticity of the toner during the pressure fixing generally used for toner fixing. Absorbed or excess molten toner in forming a smooth surface penetrates into the cellulose fibers constituting the paper, so that the outermost surface can be made smooth.
The schematic diagram of FIG. 2 shows a state where toner is fixed directly on paper. In FIG. 2, reference numeral 1 denotes paper, 2 denotes cellulose fibers, and 3 denotes a toner layer.

However, when a transparent toner is used for the purpose of imparting gloss to a chromatic color toner image, the transparent toner layer is formed on a resin surface formed with the chromatic color toner. Then, unlike the case where an image is formed directly on paper, the chromatic color toner layer becomes a wall between the paper and the elasticity of the transparent toner becomes difficult to be absorbed, or the molten material becomes excessive in forming a smooth surface. It may be difficult for the toner to escape into the cellulose fibers.
The schematic diagram of FIG. 3 shows a state where the surface of the transparent toner fixed on the chromatic toner layer is not smooth and high gloss is not obtained. In FIG. 3, reference numeral 1 is paper, 2 is cellulose fiber, 4 is a chromatic toner layer, and 5 is a transparent toner layer.
In other words, the transparent toner may be used under conditions that are more severe with respect to the higher gloss than the image formation using only the chromatic toner, and in that case, when the ratio of the storage elastic modulus (G ′) is high, Even if pressure fixing is performed, the “return” due to the elasticity of the transparent toner itself causes fine irregularities and undulations on the surface of the transparent toner layer, impairing smoothness and making it difficult to obtain high gloss.

The present inventors have conducted extensive research on this phenomenon. As a result, even when the transparent toner layer is formed on the chromatic toner layer, the tangent loss (tan δ) which is the ratio of the loss elastic modulus (G ″) to the storage elastic modulus (G ′) of the transparent toner in the fixing temperature range. If the peak of 3 is 3 or more, it is possible to make the surface of the transparent toner layer smooth and maintain a high glossiness while maintaining the resistance to hot offset and having better extensibility than the elasticity of the transparent toner. I found.
The schematic diagram of FIG. 4 shows a state where the surface is smooth and high gloss is obtained when a transparent toner having a tangent loss (tan δ) peak value of 3 or more is fixed on the chromatic toner layer. In FIG. 4, reference numeral 1 is paper, 2 is cellulose fiber, 4 is a chromatic toner layer, and 5 is a transparent toner layer.

  The peak temperature and the maximum peak value of the tangent loss (tan δ) are the viscosity of a binder resin used as a toner component (hereinafter sometimes referred to as “fixing resin”) or a crystalline polyester resin to be used. Although determined by elasticity, the peak temperature and the maximum peak value of the tangent loss (tan δ) can be changed according to the load on the resin during the toner manufacturing process, for example, melt kneading conditions. Further, since the viscoelasticity of the toner varies depending on the softening point of the crystalline polyester resin used in combination and the blending amount as the toner component, the peak temperature and the maximum peak value of the tangent loss (tan δ) can be changed. .

  The transparent toner is not only used on the chromatic color toner layer as described above, but also, for example, it is used as a “watermark” by itself on paper, or a colorless image by adding a gloss difference on paper. May be formed. However, if a minimum number of transparent toners can be used for various applications, it is not necessary to install an excessive number of types of toner in one electrophotographic device. It is advantageous for cost reduction. Further, since one electrophotographic apparatus can be used in various ways according to the user's request, it is preferable from the viewpoint of convenience. Therefore, even if the transparent toner is used for purposes other than the gloss application on the chromatic color toner layer, the maximum peak value of the tangent loss is 3 or more if the gloss application is one of the usage purposes. It is preferable.

The storage elastic modulus (G ′) in the present invention is 1 Pa or more and 1 × 10 ⁴ Pa or less at 120 to 160 ° C. More preferably, in the range of 110 to 160 ° C., the storage elastic modulus (G ′) is preferably 1 Pa or more and 1 × 10 ⁴ Pa or less. Even if the tangent loss is large, if the storage elastic modulus (G ′) in the range of 120 to 160 ° C. is higher than 1 × 10 ⁴ Pa, preferable low-temperature fixability cannot be obtained. On the other hand, if it is less than 1 Pa, the hot offset resistance is adversely affected. When the storage elastic modulus (G ′) in the range of 110 to 160 ° C. is 1 × 10 ⁴ Pa or less, still more preferable low-temperature fixability can be obtained.
Here, the storage elastic modulus (G ′) in the range of 70 to 90 ° C. is preferably 1 × 10 ⁵ Pa or more, and more preferably the storage elastic modulus (G ′) in the range of 70 to 90 ° C. is 1. It is preferable that it is x10 < ⁵ > Pa or more.

In an environment below the temperature range involved in fixing, if the storage elastic modulus (G ′) is low, the storage stability (storage stability) of the toner and the developer using the toner is adversely affected. In particular, the storage elastic modulus (G ′) in a temperature range of 90 ° C. or less has a significant effect on storage stability, and if the storage elastic modulus (G ′) of 90 ° C. or less is less than 1 × 10 ⁵ Pa, aggregation during storage And it tends to cause solidification. The lower limit of the temperature range in which the storage elastic modulus (G ′) should be 1 × 10 ⁵ Pa or more is not more than the lower limit of the temperature assumed as the storage environment of the toner. Usually, a thermoplastic resin is used as the raw material of the toner. As the storage elastic modulus (G ′) tends to increase as the temperature is lowered below the range of 70 to 90 ° C., the storage elastic modulus (G in the range of 70 to 90 ° C. is used. If the storage elastic modulus (G ′) is 1 × 10 ⁵ Pa or more in '), the storage stability in storage in the living environment can be maintained.

The storage elastic modulus (G ′) in the temperature range of 90 to 120 ° C. is not particularly specified, but as described above, the storage elastic modulus (G ′) is 1 × 10 ⁵ Pa or more in the range of 70 to 90 ° C., 120 If the toner is 1 Pa or more and 1 × 10 ⁴ Pa or less in the range of −160 ° C., the storage elastic modulus (G ′) is in the range of 1 × 10 ⁵ to 1 × 10 ⁴ Pa in the temperature range of 90 to 120 ° C. It is preferable that the storage elastic modulus (G ′) in the passing temperature range changes smoothly without a sudden peak with respect to the temperature.

The tangent loss (tan δ) of the toner is measured by measuring viscoelasticity.
In the measurement of viscoelasticity according to the present invention, a toner is molded at a pressure of 30 MPa using a die of 0.8 g and φ20 mm, and a parallel cone of φ20 mm is used with an ADVANCED RHEOMETRIC EXPANSION SYSTEM manufactured by TA, and the frequency is 1.0 Hz. Temperature increase rate 2.0 ° C./min, strain 0.1% (automatic strain control: allowable minimum stress 1.0 g / cm, allowable maximum stress 500 g / cm, maximum additional strain 200%, strain adjustment 200%) The loss elastic modulus (G ″), storage elastic modulus (G ′), and tangent loss (tan δ) were measured. At this time, the tangent loss (tan δ) when the storage elastic modulus (G ′) was 10 or less was measured. The value was excluded.

The weight average particle size (Mw) of the transparent toner in the present invention is 3 to 8 μm, and in the particle size distribution, the ratio of particles of 4 μm or less is 10 to 70% by number, and the ratio of particles of 8 μm or more is 1 to 20% by volume. It is preferable that the ratio of particles of 10.08 μm or more is 6% by volume or less.
When the weight average particle size is larger than 8 μm, toner scattering from the developing device increases, which causes the inside of the device to be contaminated or an abnormal image such as a background stain on the image medium. If the weight average particle size is less than 3 μm, the amount of heat supplied to each particle becomes relatively large, and toner fixation on the surface of the fixing roller becomes remarkable, which causes deterioration in image quality of the final image. . In addition, the production method of the toner of the present invention is not particularly limited, and may be applied to a so-called pulverized toner produced by a pulverization method or a polymerized toner produced by a polymerization method. If the particle size is smaller than 3 μm, the pulverization / classification process becomes very difficult, which causes a decrease in time efficiency and a decrease in yield in the industrial production of toner.

  The transparent toner is most required to have gloss as its function. In order to obtain a high gloss, it is necessary that the heat melting property is good, but there is a concern that the heat resistant storage stability is deteriorated as a side effect. The tendency to deteriorate the heat-resistant storage stability means that the toner tends to easily generate aggregates.

  By setting the weight average particle size (Mw) to 3 to 8 μm and the ratio of particles having a size of 4 μm or less to 70% by number or less, it is possible to achieve high definition while suppressing the occurrence of aggregates, which is a particular concern in transparent toners. A transparent toner image can be formed. When the proportion of particles of 4 μm or less is less than 10% by number, it becomes difficult to form a fine transparent toner image.

  On the other hand, when 1 to 20% by volume of particles of 8 μm or more are contained, the area covered by one toner particle when the transparent toner is fixed on the recording medium is increased, so that smoothness is improved and finally obtained. The gloss of the image increases. In particular, if the peak value of the tangent loss is 3 or more, the function is efficiently exhibited. If the particle size is 8 μm or more and less than 1% by volume, this effect is hardly exhibited. When the ratio of particles of 8 μm or more exceeds 20% by volume, the image of the transparent toner becomes rough and the smoothness is impaired, so that the glossiness is lowered.

  Further, when the ratio of particles of 10.08 μm or more is more than 6% by volume, the smoothness is improved by roughening the image rather than the smoothness improving effect due to the increase in the area covered by one toner particle. Since the effect which is spoiled becomes remarkable, glossiness falls as a result. Further, it becomes difficult to obtain a high-definition transparent toner image.

  The Coulter Counter method can be used to measure the particle size distribution (number distribution, volume distribution) of the toner particles, and the Coulter Counter TA-II and Coulter Multisizer II, III, and IV (all of which are Coulter counters) can be used. Etc.). The measurement method is described below.

First, 0.1 to 5 ml of a surfactant (preferably polyoxyethylene alkyl ether) is added as a dispersant to 100 to 150 ml of an aqueous electrolytic solution. Here, the electrolytic solution is prepared by preparing an about 1% NaCl aqueous solution using primary sodium chloride, and for example, ISOTON-II (manufactured by Coulter) can be used. Here, 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the measurement device is used to measure the volume and number of toner particles or toner using a 100 μm aperture as an aperture. Volume distribution and number distribution are calculated. From the obtained distribution, the weight average particle diameter (Mw) and the volume average particle diameter (Mv) of the toner can be obtained.
As channels, 2.00 to less than 2.52 μm; 2.52 to less than 3.17 μm; 3.17 to less than 4.00 μm; 4.00 to less than 5.04 μm; 5.04 to less than 6.35 μm; 6 Less than 35 to 8.00 μm; less than 8.00 to less than 10.08 μm; less than 10.08 to less than 12.70 μm; less than 12.70 to less than 16.00 μm; less than 16.00 to less than 20.20 μm; Uses 13 channels of less than 40 μm; 25.40 to less than 32.00 μm; 32.00 to less than 40.30 μm, and targets particles having a particle size of 2.00 μm to less than 40.30 μm.

  As the composition (raw material or constituent material) of the transparent toner for electrophotographic development of the present invention, at least a binder resin (fixing resin), a crystalline polyester resin, a lubricant, and the like will be described below.

[Binder resin]
Conventionally known resins can be used for the binder resin (fixing resin) used as the toner raw material of the present invention. For example, styrene, poly-α-still styrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer, styrene -Styrene such as maleic acid copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloroacrylic acid methyl copolymer, styrene-acrylonitrile-acrylic acid ester copolymer Resin (monopolymer or copolymer containing styrene or styrene-substituted product), epoxy resin, vinyl chloride resin, rosin-modified maleic acid resin, phenol resin, polyethylene resin, polypropylene resin, petroleum resin, polyurethane resin, ketone resin, Ethylene-ethyl acrylate copolymer Examples thereof include coalescence, xylene resin, and polyvinyl butyrate resin. Moreover, the manufacturing method of these resin is not specifically limited, either bulk polymerization, solution polymerization, emulsion polymerization, and suspension polymerization can be used.
In the present invention, it is preferable to contain a polyester resin as the binder resin (fixing resin), and it is particularly preferable that the polyester resin is the main component. A polyester resin is generally a binder resin suitable for the present invention because it can be fixed at low temperature while maintaining heat-resistant storage stability compared to other resins.

The polyester resin used in the present invention is obtained by condensation polymerization of alcohol and carboxylic acid. Examples of the alcohol used include glycols such as ethylene glycol, diene glycol, triethylene glycol, and propylene glycol, and etherified bisphenols such as 1,4-bis (hydroxymeta) cyclohexane and bisphenol A, and other divalent compounds. And trihydric or higher polyhydric alcohol monomers.
Examples of the carboxylic acid include divalent organic acid monomers such as maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, succinic acid, and malonic acid, 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methylene Mention may be made of trivalent or higher polyvalent carboxylic acid monomers such as carboxypropane, 1,2,7,8-octanetetracarboxylic acid. Here, the Tg of the polyester resin is preferably 50 to 75 ° C.

[Crystalline polyester resin]
The transparent toner of the present invention contains a crystalline polyester resin as a thermoplastic resin. When a crystalline polyester resin is used in combination, fixing at a low temperature becomes possible and the glossiness of an image can be improved even at a low temperature. The content of the crystalline polyester resin is preferably 1 to 25 parts by weight, more preferably 1 to 15 parts by weight with respect to 100 parts by weight of the binder resin (for example, polyester resin). If the ratio of the crystalline polyester resin is too high, filming is likely to occur on the surface of the image carrier such as a photoconductor, and storage stability may be deteriorated. Furthermore, if the ratio of the crystalline polyester resin is too high, the transparency of the resin is impaired, and the transparency required for the transparent toner cannot be ensured.

  The crystalline polyester resin used in the present invention is, for example, (1) a linear unsaturated aliphatic divalent carboxylic acid or a reactive derivative thereof (an acid anhydride, a lower alkyl ester acid halide having 1 to 4 carbon atoms, etc.). And (2) a polyhydric alcohol unit comprising a linear aliphatic diol can be produced by a polycondensation reaction by a conventional method. In this case, the polyvalent carboxylic acid unit may contain a small amount of other polyvalent carboxylic acid units as necessary. In addition, the crystalline polyester resin exhibits an operational effect that a linear unsaturated aliphatic dicarboxylic acid unit is used as the carboxylic acid unit, so that a crystal structure is easily formed as compared with the case where the aromatic dicarboxylic acid unit is used. .

  The polyvalent carboxylic acid unit includes (1) an unsaturated aliphatic divalent carboxylic acid unit having a branched chain, (2) a saturated aliphatic divalent carboxylic acid, a saturated aliphatic trivalent carboxylic acid, and the like. In addition to polyvalent carboxylic acid units, (3) aromatic polyvalent carboxylic acid units such as aromatic divalent carboxylic acids and aromatic trivalent carboxylic acids are included. The content of these polyvalent carboxylic acid units is usually 30 mol% or less, preferably 10 mol% or less, based on the total carboxylic acid, and is suitably added within the range in which the resulting polyester has crystallinity. .

  Specific examples of polyvalent carboxylic acid units that can be added as needed include malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, citraconic acid, phthalic acid, isophthalic acid, terephthalic acid, etc. A divalent carboxylic acid unit: trimetic anhydride, 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid 1,3,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methylenecarboxypropane, 1,2,7,8-octanetetracarboxylic acid, etc. be able to.

  In the polyhydric alcohol unit, if necessary, in addition to a small amount of an aliphatic branched dihydric alcohol unit or a cyclic dihydric alcohol unit, a trihydric or higher polyhydric alcohol unit is obtained. You may add suitably in the range which has. Examples of polyhydric alcohol units added as necessary include 1,4-bis (hydroxymethyl) cyclohexane units, polyethylene glycol units, bisphenol A ethylene oxide adduct units, bisphenol A propylene oxide adduct units, glycerin units, and the like. Is mentioned.

  In the crystalline polyester resin, the molecular weight distribution is preferably sharp from the viewpoint of low-temperature fixability, and the molecular weight is preferably a relatively low molecular weight. Here, the softening temperature of the crystalline polyester resin (measured by an elevated flow tester CFT-100D type (manufactured by Shimadzu Corporation)) is not limited, but is preferably about 60 to 120 ° C.

[Lubricant]
The transparent toner of the present invention needs to contain a lubricant. That is, since the transparent toner is located at the uppermost part of the image, high hot offset resistance is required, and the release property from the fixing member can be increased by containing a lubricant. Such a lubricant preferably contains at least one selected from a higher aliphatic alcohol / higher fatty acid lubricant, a fatty acid amide lubricant, an aliphatic hydrocarbon lubricant, a metal soap lubricant, and a fatty acid ester lubricant.
Specific examples of the lubricant include liquid paraffin, microristane wax, natural paraffin, synthetic paraffin, polyolefin wax, and partial oxides thereof, or aliphatic hydrocarbon lubricants such as fluoride and chloride, beef tallow, Animal oil such as fish oil, palm oil, soybean oil, rapeseed oil, vegetable oil such as rice bran wax, carnauba wax, higher fatty alcohol / higher fatty acid lubricant such as montan wax, fatty acid amide, fatty acid bisamide, zinc stearate, calcium stearate, Metal soap lubricants such as magnesium stearate, aluminum stearate, zinc oleate, zinc palmitate, magnesium palmitate, zinc myristate, zinc laurate, zinc behenate, fatty acid ester lubricants, polyvinylidene fluoride, etc. Can use is not limited thereto.
As the lubricant, a single lubricant or a combination of a plurality of lubricants can be used, and the lubricant is not limited. For example, a higher aliphatic alcohol / higher fatty acid lubricant and a fatty acid amide lubricant are preferably used.

When the lubricant is contained in the toner, it is contained in an amount of 0.1 to 15 parts by weight, preferably 1 to 7 parts by weight with respect to 100 parts by weight of the binder resin (fixing resin). By containing a lubricant inside the toner, hot offset resistance and fixing strength at the time of fixing can be obtained, and high rubbing test strength can be obtained. Thereby, when used in a high-speed image forming apparatus, low-temperature fixability can be secured. When the amount of lubricant added is less than 0.1 parts by weight, offset is likely to occur, and when it exceeds 10 parts by weight, carrier spent is likely to occur, and image quality is likely to deteriorate. When the toner surface layer contains a lubricant, it is preferably contained in an amount of 0.001 to 1 part by weight, preferably 0.01 to 0.3 part by weight, based on 100 parts by weight of the fixing resin.
As described above, when the toner surface layer contains a lubricant, the lubricant comes into direct contact with the image carrier, so that a thin film is formed on the surface of the image carrier to prevent the toner from being easily peeled off or reattached. Is effective.

The inclusion of a fatty acid amide-based lubricant in the toner is preferable because, in addition to the effect as a lubricant, crystallization of the crystalline polyester is promoted and storage stability can be improved. Fatty acid amide-based lubricants may be used alone, but may be used in combination with lubricants other than fatty acid amide-based lubricants in order to separate and control the release function and the crystallization promoting function of crystalline polyester. . For example, carnauba wax or paraffin wax that is effective for releasability and a fatty acid amide wax may be used in combination. Examples of the fatty acid amide wax include stearic acid amide, oleic acid amide, erucic acid amide, ethylene-bis stearic acid amide and the like. A particularly effective and preferred example is N, N′-ethylene-bisstearic acid amide.
That is, the storage stability can be further improved by including a fatty acid amide lubricant. When the fatty acid amide lubricant is N, N′-ethylene-bisstearic acid amide, the effect of storage stability by the fatty acid amide lubricant can be maximized.

[Other components]
Further, a charge control agent, which will be described later, can be contained as necessary as a composition of the toner of the present invention. Moreover, the external additive etc. which are mentioned later can also be contained.

The image forming method of the present invention comprises a step of charging at least the surface of an image carrier, a step of developing an electrostatic latent image formed on the charged image carrier using the transparent toner for electrophotography, The method includes a step of transferring a transparent toner image formed on an image carrier onto a recording medium, and a fixing step of fixing the transparent toner image transferred onto the recording medium by a fixing member. is there. This makes it possible to form an electrophotographic image using a transparent toner for electrophotography that achieves both excellent low-temperature fixability, hot offset resistance, and storage stability, and achieves high gloss even in low-temperature fixing. Can do.
Here, an image forming method comprising a step of forming a color image using one or more kinds of chromatic toner on the recording medium and a step of forming a transparent toner image using the transparent toner for electrophotography. By doing so, it is possible to give gloss to an image using chromatic color toner.
Further, if at least one layer of the transparent toner image after fixing is formed on the outermost surface of the recording medium on which the image is fixed, the glossiness of the transparent toner can be more efficiently drawn out. If the layer thickness of the transparent toner image is 1 to 15 μm, good fixing strength and transparency can be obtained while obtaining a sufficient gloss.

The method for forming the toner layer with the transparent toner on the outermost surface is not particularly limited. However, as a configuration of the developing device or the developing unit when the transparent toner is used together with the chromatic color toner, for example, a chromatic color toner is provided. Each is equipped with a transparent toner and is used to develop on an image carrier, an intermediate carrier, or a recording medium with a chromatic toner, and then develop with a transparent toner. This can be realized. In this case, in terms of the flow of the development process, the development process using the transparent toner is provided downstream of the development process using the chromatic toner.
If four color toners of yellow, magenta, cyan, and black are used as chromatic color toners, a developing device or developing unit using transparent toner is provided in addition to the developing devices or developing units for these four colors (total 5). The present invention is realized by using an electrophotographic developing apparatus (described in detail later) as shown in FIG. 5 equipped with two developing apparatuses or developing units.

  In the case of forming an image using the transparent toner of the present invention, the image forming apparatus to be used can be sufficiently fixed by one time. Latent image formation, exposure, development with chromatic toner and transparent toner during image formation, transfer to recording medium, fixing with fixing machine, and further latent image formation and exposure with chromatic toner in second image formation , Developed, transferred to a recording medium, and fixed by a fixing device. As a result, the normally glossy portion is fixed once and the highly glossy portion passes through the fixing device twice.

  By passing the fixing machine twice, the portion where the transparent toner is formed has a larger amount of toner than the portion where the transparent toner is not formed, but a sufficient amount of heat can be supplied by passing the fixing machine twice. Furthermore, the smoothness of the surface is increased and high gloss can be obtained. Normally, the glossy portion is not used at a low fixing temperature, but is used with a heat amount sufficient to maintain a sufficient fixing strength by one fixing. In the image forming apparatus used in the present invention, the transparent toner that realizes high gloss is formed on the top of the chromatic toner and contacts the fixing device. Therefore, the releasability higher than that of the chromatic toner, hot offset resistance, and High gloss is required.

  The glossiness of the chromatic toner can be selected according to the purpose of use. When high glossiness is required as a whole, a toner having a small weight average molecular weight (Mw) / number average molecular weight (Mn) may be used. When low glossiness is required, the toner weight average What has a large molecular weight (Mw) / number average molecular weight (Mn) may be selected. In the present invention, although not limited, for example, those having a weight average molecular weight (Mw) / number average molecular weight (Mn) in the range of about 2 to 6 are preferably used.

  However, when the gloss of the chromatic toner is high, the gloss of the transparent toner tends to be high, but the gloss difference on the recording medium is low. On the other hand, when a chromatic color toner having a low gloss is used, the gloss difference on the recording medium tends to be large, but even if a transparent toner is placed, a high gloss is not easily produced. This is because in the case of a chromatic color toner with low gloss, the chromatic color toner resin itself exerts a force to return to its original state due to elasticity, so that light scattering easily occurs at the interface between the chromatic color toner and the transparent toner.

  Thus, when the gloss of the chromatic toner is low, high gloss can be achieved by increasing the thickness of the transparent toner layer. In the present invention, the layer thickness of the transparent toner image after fixing formed on the chromatic toner is preferably 1 to 15 μm. When the layer thickness is less than 1 μm, it is difficult to achieve high gloss, and when it exceeds 15 μm, the fixing strength is weakened, the transparency is deteriorated, and the color reproducibility of the chromatic toner is deteriorated. The thickness of the toner layer can be measured by cutting the recording medium with a microtome.

The transparent toner and chromatic color toner used in the present invention can contain a charge control agent. Examples of charge control agents include modified products of nigrosine and fatty acid metal salts, onium salts such as phosphonium salts and lake lakes thereof, triphenylmethane dyes and lake lake pigments, metal salts of higher fatty acids; dibutyltin oxide, dioctyltin oxide Diorganotin oxides such as dicyclohexyltin oxide; diorganotin borates such as dibutyltin borate, dioctyltin borate, dicyclohexyltin borate, organometallic complexes, chelate compounds, monoazo metal complexes, acetylacetone metal complexes, aromatic hydroxycarboxylic acids, There are aromatic dicarboxylic acid metal complexes and quaternary ammonium salts. Others include aromatic hydroxycarboxylic acids, aromatic mono- and polycarboxylic acids and their metal salts, anhydrides, esters, phenol derivatives such as bisphenols. These can be used alone or in combination of two or more.
When these charge control agents are internally added to the toner, it is preferable to add 0.1 to 10 parts by weight with respect to the binder resin (fixing resin). In the case of transparent toner, select a white or transparent color as much as possible.

  Further, the transparent toner and the chromatic toner can contain an external additive. External additives include, for example, abrasives such as silica, Teflon resin powder, polyvinylidene fluoride powder, cerium oxide powder, silicon carbide powder, strontium titanate powder, or, for example, titanium oxide powder, oxidation Development of fluidity-imparting agent such as aluminum powder, anti-aggregation agent, resin powder, or conductivity-imparting agent such as zinc oxide powder, antimony oxide powder and tin oxide powder, and white and black particles with opposite polarity It can also be used as a property improver. These can be used singly or in combination, and are selected so as to have resistance against development stress such as idling.

  When the transparent toner and the chromatic toner used in the present invention are used in a two-component developer system, as magnetic fine particles used for the magnetic carrier, spinel ferrite such as magnetite and gamma iron oxide, metals other than iron (Mn, Ni, Zn, Mg, Cu, etc.) can be used. Magnetoplumbite type ferrite such as spinel ferrite and barium ferrite containing one or more kinds, and iron or alloy particles having an oxide layer on the surface can be used. The shape may be granular, spherical, or needle-shaped. In particular, when high magnetization is required, it is preferable to use ferromagnetic fine particles such as iron. In view of chemical stability, it is preferable to use magnetoplumbite type ferrites such as spinel ferrite and barium ferrite containing magnetite and gamma iron oxide. Specifically, MFL-35S, MFL-35HS (manufactured by Powder Tech), DFC-400M, DFC-410M, SM-350NV (manufactured by Dowa Iron Powder Industry Co., Ltd.) and the like are preferable examples.

By selecting the type and content of the ferromagnetic fine particles, a resin carrier having a desired magnetization can be used. At this time, the magnetic property of the carrier is 1,000 oersted (79 × 10 ³ A / m), and the strength of magnetization is 30 to 150 emu / g [(30 to 150) × (4π) ² · 10 ⁻¹⁰ Hm ² / kg] is preferred. Such a resin carrier is manufactured by spraying a melt-kneaded product of magnetic fine particles and an insulating binder resin with a spray dryer, or reacting and curing a monomer or prepolymer in an aqueous medium in the presence of the magnetic fine particles. A resin carrier in which magnetic fine particles are dispersed in a condensed binder can be produced.

  Chargeability can be controlled by fixing positively or negatively charged fine particles or conductive fine particles on the surface of the magnetic carrier, or coating a resin. Silicone resin, acrylic resin, epoxy resin, fluorine resin, etc. are used as the coating material on the surface, and it can be coated with positive or negatively charged fine particles or conductive fine particles. Silicone resin and acrylic resin Is preferred.

  In the present invention, the weight ratio of the carrier in the developer accommodated in the developing device is preferably 85 wt% or more and less than 98 wt%. If it is less than 85 wt%, toner scattering from the developing device is likely to occur, causing a defective image. If it is 98 wt% or more, the charge amount of the toner excessively increases or the supply amount of the toner is insufficient, so that the image density is lowered and a defective image is caused.

In order to produce the transparent toner and the chromatic toner in the present invention, the toner raw material [[For transparent toner, for example, a binder resin (fixing resin), a crystalline polyester resin and a lubricant, and if necessary, a charge control agent, Additives, etc.] [for chromatic toner, for example, binder resin (fixing resin) and lubricant, colorant if necessary, and charge control agent, lubricant, additive, etc. if necessary]] uniformly After the toner components dispersed in the mixture are sufficiently mixed by a mixer such as a Henschel mixer or a super mixer, the raw materials are sufficiently mixed by melting and kneading using a hot melt kneader such as a heating roll, kneader or extruder. After cooling and solidification, fine pulverization and classification are performed to obtain a toner. An additive (external additive) can be mixed with the particles (base particles) obtained by classification.
As the pulverization method, the toner is included in a high-speed air current, the toner collides with the collision plate, and the energy is pulverized by the jet mill method. The particle-particle collision method in which the toner particles collide with each other in the air current. A mechanical pulverization method in which toner is supplied between the rotor and a narrow gap and pulverized can be used.

In addition, an oil phase in which a toner raw material is dissolved or dispersed in an organic solvent phase is dispersed in an aqueous medium phase, a resin is reacted, and then the solvent is removed, followed by filtration, washing, and drying, thereby forming a toner base. The toner can also be produced using a solution suspension method for producing particles. Further, a toner base may be produced by a polyester elongation method. An additive (external additive) can be mixed with the obtained particles (base particles).
As the external additive, for example, fatty acid metal salt, zinc stearate, calcium stearate, lead stearate, zinc oxide powder, aluminum oxide powder, titanium oxide powder, fine powder silica or the like is used as inorganic fine particles. it can. Resin fine particles can also be used.

A schematic configuration showing an example of the electrophotographic developing apparatus used in the present invention is shown in FIG.
In FIG. 5, reference numeral 101A is a driving roller, 101B is a driven roller, 102 is a photosensitive belt, 103 is a charger, 104 is a laser writing system unit, and 105A to 105D are toners of yellow, magenta, cyan, and black, respectively. A developing unit for storing, a developing unit for storing transparent toner 105E, a paper feeding cassette 106, an intermediate transfer belt 107, a drive shaft roller 107A for driving the intermediate transfer belt, and a driven shaft 107B for supporting the intermediate transfer belt A roller 108, a cleaning device 109, a fixing roller 109, a pressure roller 109A, a paper discharge tray 110, and a paper transfer roller 113 are shown.

  In the color image forming apparatus shown in FIG. 5, a flexible intermediate transfer belt 107 is used with respect to the transfer drum. The intermediate transfer belt 107 as an intermediate transfer member includes a drive shaft roller 107A and a pair of driven shaft rollers. The belt surface between the pair of driven shaft rollers 107B is in contact with the photosensitive belt 102 on the outer periphery of the driving roller 101A from the horizontal direction.

  During normal color image output, each color toner image formed on the photoreceptor belt 102 is transferred to the intermediate transfer belt 107 each time it is formed, and the color toner images are combined, and this is fed into the paper feed cassette 106. The transfer sheet is transferred onto the transfer sheet by the paper transfer roller 113, and the transferred transfer sheet is transferred between the fixing roller 109 and the pressure roller 109A of the fixing device, and is fixed by the fixing roller 109 and the pressure roller 109A. After fixing, the paper is discharged onto the paper discharge tray 110.

  When the developing units 105A to 105E develop toner, the toner concentration of the developer stored in the developing unit is lowered. A decrease in the toner density of the developer is detected by a toner density sensor (not shown). When a decrease in toner density is detected, a toner replenishing device (not shown) connected to each developing unit operates to replenish the toner and increase the toner density. At this time, the replenished toner may be a so-called trickle developing system developer in which a carrier and toner are mixed as long as the developing unit has a developer discharging mechanism.

  In FIG. 5, an image is formed by superimposing a toner image on an intermediate transfer belt. However, the electrophotography of the present invention is also applied to a system that directly transfers from a transfer drum to a recording medium without using an intermediate transfer belt. An image forming apparatus can be obtained.

FIG. 6 is a schematic view showing an example of a developing device used in the present invention, and modifications as described later also belong to the category of the present invention.
In FIG. 6, a developing device (40) disposed opposite to a photosensitive drum (20) as a latent image carrier includes a developing sleeve (41) as a developer carrier and a developer containing member (42). It is mainly composed of a doctor blade (43) as a regulating member, a support case (44) and the like. To a support case (44) having an opening on the side of the photosensitive drum (20), a toner hopper (45) as a toner storage portion for storing the toner (21) is joined.

  In the developer accommodating portion (46) for accommodating the developer composed of the toner (21) and the carrier (23) adjacent to the toner hopper (45), the toner (21) and the carrier (23) are agitated. A developer stirring mechanism (47) is provided for imparting friction / release charges to (21). Inside the toner hopper (45), a toner agitator (48) and a toner replenishing mechanism (49) are disposed as toner supplying means rotated by a driving means (not shown). The toner agitator (48) and the toner replenishing mechanism (49) send out the toner (21) in the toner hopper (45) toward the developer container (46) while stirring.

  A developing sleeve (41) is disposed in a space between the photosensitive drum (20) and the toner hopper (45). The developing sleeve (41) driven to rotate in the direction of the arrow by a driving means (not shown) is arranged in a relative position relative to the developing device (40) in order to form a magnetic brush by the carrier (23). A magnet (not shown) is provided as magnetic field generating means.

  A doctor blade (43) is integrally attached to the developer accommodating member (42) on the side facing the side attached to the support case (44). In this example, the doctor blade (43) is disposed in a state where a certain gap is maintained between the tip thereof and the outer peripheral surface of the developing sleeve (41).

  Using such a device without limitation, the image forming method of the present invention is performed as follows. That is, with the above configuration, the toner (21) sent out from the toner hopper (45) by the toner agitator (48) and the toner replenishing mechanism (49) is transported to the developer accommodating portion (46), where the developer agitation is performed. By stirring by the mechanism (47), a desired friction / separation charge is imparted, and is carried on the developing sleeve (41) as a developer together with the carrier (23) and faces the outer peripheral surface of the photosensitive drum (20). The toner image is formed on the photosensitive drum (20) by electrostatically coupling only the toner (21) with the electrostatic latent image formed on the photosensitive member (20). .

FIG. 7 is a schematic configuration diagram illustrating an example of an image forming apparatus having the developing device of FIG.
In FIG. 7, an image carrier charging member [charging member] (32), an image exposure system (33), a developing device (40), and a transfer mechanism [around a drum-shaped photosensitive member [photosensitive drum] (20). The transfer device] (50), the cleaning mechanism [cleaning device] (60), and the charge removal lamp (70) are arranged. In this example, the surface of the charging member (32) is the surface of the photosensitive drum (20). Is in a non-contact state with a gap of about 0.2 mm, and when charging the photosensitive drum (20) by the charging member (32), direct current is applied to the charging member (32) by a voltage application means (not shown). By charging the photosensitive drum (20) with an electric field in which an AC component is superimposed on the component, charging unevenness can be reduced, which is effective. The image forming method including the developing method is performed by the following operation.

  A series of image forming processes can be described as a negative-positive process. A photosensitive drum (20) represented by a photosensitive member (OPC) having an organic photoconductive layer is neutralized by a static elimination lamp (70) and is uniformly negatively charged by a charging member (32) such as a charging charger or a charging roller. Then, a latent image is formed by laser light emitted from an image exposure system (33) such as a laser optical system (in this example, the absolute value of the exposed portion potential is lower than the absolute value of the non-exposed portion potential). Done.

  Laser light is emitted from a semiconductor laser and scans the surface of the photosensitive drum (20) in the direction of the rotation axis of the photosensitive drum (20) by a polygonal polygonal mirror (polygon) that rotates at high speed. The latent image formed in this way is developed with a developer composed of a mixture of toner and carrier supplied on a developing sleeve (41) which is a developer carrying member in the developing device (40), and the toner image is developed. It is formed. When developing the latent image, a voltage application mechanism (not shown) is applied to the developing sleeve (41), and a DC voltage of an appropriate magnitude between the exposed portion and the non-exposed portion of the photosensitive drum (20) is applied. A developing bias superimposed with an AC voltage is applied.

  On the other hand, a transfer medium (for example, paper) (80) is fed from a paper feed mechanism (not shown), and is synchronized with the leading edge of the image by a pair of upper and lower registration rollers (not shown), and a photosensitive drum ( 20) and the transfer device (50), and the toner image is transferred. At this time, it is preferable that a potential having a polarity opposite to the polarity of toner charging is applied to the transfer device (50) as a transfer bias. Thereafter, the transfer medium (80) is separated from the photosensitive drum (20) to obtain a transfer image.

  The toner remaining on the photosensitive drum (20) is collected in the toner collecting chamber (62) in the cleaning device (60) by a cleaning blade (61) as a cleaning member. The collected toner may be transported to a developer container (reference numeral 46 in FIG. 6) and / or a toner hopper (45) by a toner recycling means (not shown) and reused. Reference numeral 47 denotes a developer stirring mechanism.

  The image forming apparatus may be a device in which a plurality of the developing devices described above are arranged, and the toner images are sequentially transferred onto the transfer medium, then sent to the fixing mechanism, and the toner is fixed by heat or the like. An apparatus may be used in which a plurality of toner images are transferred to a transfer medium and transferred together onto a transfer medium and fixed in the same manner.

  FIG. 8 is a schematic configuration diagram showing another example of an image forming apparatus used in the image forming method of the present invention. In FIG. 8, at least a photosensitive layer is provided on a conductive support, and the photosensitive member (20) is driven by driving rollers (24a) and (24b) and charged by a charging member (32), and an image exposure system. Image exposure by (33), development by developing device (40), transfer using transfer device [transfer mechanism] (50), exposure before cleaning by exposure light source (26) before cleaning, brush-like cleaning means (64) and cleaning blade Cleaning by (61) and static elimination by the static elimination lamp (70) are repeated. In FIG. 8, the photoconductor (20) (of course, the support is translucent in this case) is subjected to pre-cleaning exposure from the support side.

The process cartridge of the present invention can use an image carrier and at least an electrostatic latent image formed on the image carrier using the transparent toner for electrophotographic development of the present invention or a developer comprising the toner and a carrier. And at least developing means for visual images, and is configured to be detachable from the image forming apparatus main body. Here, the process cartridge can have other means selected from a charging means, an exposure means, a developing means, a transfer means, a cleaning means, and a charge eliminating means as required.
An example of the process cartridge used in the present invention is shown in the schematic configuration diagram of FIG.
The process cartridge shown in FIG. 9 uses the transparent toner of the present invention or a developer composed of the toner and a carrier, and includes a photoconductor (20), a proximity brush-shaped contact charging means [charging means] (32), An image forming apparatus integrally supporting a developing means [developing apparatus] (40) for storing a transparent toner of the present invention or a developer comprising the toner and a carrier, and a cleaning means (61) having at least a cleaning blade as a cleaning means. The process cartridge is detachable from the main body. In the present invention, the above-described components can be integrally combined as a process cartridge, and the process cartridge can be configured to be detachable from a main body of an image forming apparatus such as a copying machine or a printer.
By using the transparent toner as the developing means of the process cartridge according to the present invention, an electrophotography having both excellent low temperature fixability, hot offset resistance and storage stability, and high glossiness even at low temperature fixing. An image can be formed.

  Hereinafter, the present invention will be described with reference to examples and comparative examples. In addition, this invention is not limited to the Example illustrated here. In the following, “parts” represents parts by weight, and “%” represents% by weight.

[Production of toner]
(Example of production of transparent toner 1)
The toner raw material of the following prescription 1 is premixed using a Henschel mixer (Mitsui Miike Chemical Co., Ltd., FM20B) and then 100-130 ° C. with a twin-screw kneader (Ikegai Co., Ltd., PCM-30). The mixture was melted and kneaded at the following temperature. The obtained kneaded product was cooled to room temperature and then coarsely pulverized to 200 to 300 μm with a hammer mill. Subsequently, after finely pulverizing using a supersonic jet pulverizer lab jet (manufactured by Nippon Pneumatic Industry Co., Ltd.), the weight average particle diameter is 5. 5 with an airflow classifier (manufactured by Nippon Pneumatic Industry Co., Ltd., MDS-I). Classification was performed while appropriately adjusting the louver opening so as to be 6 ± 0.2 μm to obtain toner base particles. Next, 1.0 part by weight of an additive (HDK-2000, manufactured by Clariant Co., Ltd.) was stirred and mixed with a Henschel mixer with respect to 100 parts by mass of the toner base particles, whereby a transparent toner 1 was produced.
<Toner raw material formulation 1>
Polyester resin (A): 100 parts by weight [Tg; 64.0 ° C., Mw; 15300, Mn; 3800, acid value 7.0 mgKOH / g,
Tangent loss peak temperature; 143.7 ° C.]
Crystalline polyester resin (A) [softening temperature 70 ° C.]: 5 parts by weight Carnauba wax (A) [manufactured by Celerica NODA]: 5 parts by weight N, N′-ethylene-bisstearic acid amide (A) [manufactured by Kao] : 2 parts by weight

(Production example of transparent toner 2)
A transparent toner 2 was produced in the same manner as the transparent toner 1 except that the toner raw material of the following formulation 2 was used.
<Toner raw material formulation 2>
Polyester resin (A): 100 parts by weight Crystalline polyester resin (A): 15 parts by weight Carnauba wax (A): 5 parts by weight N, N′-ethylene-bisstearic acid amide (A): 2 parts by weight

(Example of production of transparent toner 3)
A transparent toner 3 was produced in the same manner as the transparent toner 1 except that the toner raw material of the following formulation 3 was used.
<Toner raw material formulation 3>
Polyester resin (B): 100 parts by weight [Tg: 67.5 ° C., Mw: 18700, Mn: 4900, acid value: 6.6 mgKOH / g,
Tangent loss peak temperature; 156.5 ° C.]
Crystalline polyester resin (A): 5 parts by weight Carnauba wax (A): 5 parts by weight N, N′-ethylene-bisstearic acid amide (A): 2 parts by weight

(Example of production of transparent toner 4)
A transparent toner 4 was produced in the same manner as the transparent toner 1 except that the toner raw material of the following formulation 4 was used.
<Toner raw material formulation 4>
Polyester resin (B): 100 parts by weight Crystalline polyester resin (A): 10 parts by weight Carnauba wax (A): 5 parts by weight N, N′-ethylene-bisstearic acid amide (A): 2 parts by weight

(Production example of transparent toner 5)
A transparent toner 5 was produced in the same manner as the transparent toner 1 except that the toner raw material of the following prescription 5 was used.
<Toner raw material formulation 5>
Polyester resin (C): 100 parts by weight [Tg; 62.0 ° C., Mw; 15200, Mn; 3700, acid value 7.2 mgKOH / g,
Tangent loss peak temperature; 150.0 ° C]
Crystalline polyester resin (A): 10 parts by weight Carnauba wax (A): 5 parts by weight N, N′-ethylene-bisstearic acid amide (A): 2 parts by weight

(Production example of transparent toner 6)
A transparent toner 6 was produced in the same manner as the transparent toner 1 except that the toner raw material of the following prescription 6 was used.
<Toner raw material formulation 6>
Polyester resin (D): 100 parts by weight [Tg; 61.0 ° C., Mw; 15100, Mn; 3700, acid value 7.2 mgKOH / g,
Tangent loss peak temperature; 147.0 ° C.]
Crystalline polyester resin (A): 10 parts by weight Carnauba wax (A): 5 parts by weight N, N′-ethylene-bisstearic acid amide (A): 2 parts by weight

(Production example of transparent toner 7)
A transparent toner 7 was produced in the same manner as the transparent toner 1 except that the toner raw material of the following formulation 7 was used.
<Toner raw material formulation 7>
Polyester resin (E): 100 parts by weight [Tg: 68.0 ° C., Mw: 18800, Mn: 5000, acid value: 6.6 mgKOH / g,
Tangent loss peak temperature; 157.0 ° C.]
Crystalline polyester resin (A): 2 parts by weight Carnauba wax (A): 5 parts by weight N, N′-ethylene-bisstearic acid amide (A): 2 parts by weight

(Production example of transparent toner 8)
A transparent toner 8 was produced in the same manner as the transparent toner 1 except that the toner raw material of the following formulation 8 was used.
<Toner raw material formulation 8>
Polyester resin (E): 100 parts by weight Crystalline polyester resin (A): 5 parts by weight Carnauba wax (A): 5 parts by weight N, N′-ethylene-bisstearic acid amide (A): 2 parts by weight

(Production example of transparent toner 9)
A transparent toner 9 was produced in the same manner as the transparent toner 1 except that the toner raw material of the following prescription 9 was used.
<Toner raw material formulation 9>
Polyester resin (F): 100 parts by weight [Tg: 65.0 ° C., Mw: 18500, Mn: 4700, acid value 6.5 mgKOH / g,
Tangent loss peak temperature; 128.0 ° C]
Crystalline polyester resin (A): 20 parts by weight Carnauba wax (A): 5 parts by weight N, N′-ethylene-bisstearic acid amide (A): 2 parts by weight

(Example of production of transparent toner 10)
A transparent toner 10 was produced in the same manner as the transparent toner 1 except that the toner raw material having the following formulation 10 was used.
<Toner raw material formulation 10>
Polyester resin (F): 100 parts by weight Crystalline polyester resin (A): 15 parts by weight Carnauba wax (A): 5 parts by weight N, N′-ethylene-bisstearic acid amide (A) 2 parts by weight

(Example of production of transparent toner 11)
A transparent toner 11 was produced in the same manner as the transparent toner 1 except that a toner raw material having the following formulation 11 was used.
<Toner raw material formulation 11>
Polyester resin (G): 100 parts by weight [Tg; 63.0 ° C., Mw; 18400, Mn; 4600, acid value 6.5 mgKOH / g,
Tangent loss peak temperature; 134.0 ° C.]
Crystalline polyester resin (A): 15 parts by weight Carnauba wax (A): 7 parts by weight N, N′-ethylene-bisstearic acid amide (A): 2 parts by weight

(Example of production of transparent toner 12)
A transparent toner 12 was produced in the same manner as the transparent toner 1 except that a toner raw material having the following formulation 12 was used.
<Toner raw material formulation 12>
Polyester resin (G): 100 parts by weight Crystalline polyester resin (A): 10 parts by weight Carnauba wax (A): 7 parts by weight N, N′-ethylene-bisstearic acid amide (A): 2 parts by weight

(Example of production of transparent toner 13)
A transparent toner 13 was produced in the same manner as the transparent toner 1 except that the toner raw material having the following formulation 13 was used.
<Toner raw material formulation 13>
Polyester resin (H): 100 parts by weight [Tg; 66.0 ° C., Mw; 15400, Mn; 3900, acid value 7.0 mgKOH / g,
Tangent loss peak temperature; 142.0 ° C]
Crystalline polyester resin (A): 10 parts by weight Carnauba wax (A): 5 parts by weight N, N′-ethylene-bisstearic acid amide (A): 2 parts by weight

(Example of production of transparent toner 14)
A transparent toner 14 was produced in the same manner as the transparent toner 1 except that the toner raw material having the formulation 14 shown below was used.
<Toner raw material formulation 14>
Polyester resin (H): 100 parts by weight Crystalline polyester resin (A): 10 parts by weight Carnauba wax (A): 5 parts by weight Stearic acid amide (A) [manufactured by Kao]: 2 parts by weight

(Example of production of transparent toner 15)
A transparent toner 15 was produced in the same manner as the transparent toner 1 except that a toner raw material having the following formulation 15 was used.
<Toner raw material formulation 15>
Polyester resin (H): 100 parts by weight Crystalline polyester resin (A): 10 parts by weight

(Example of production of transparent toner 16)
A transparent toner 16 was produced in the same manner as the transparent toner 1 except that the toner raw material having the following formulation 16 was used.
<Toner raw material formulation 16>
Polyester resin (H): 100 parts by weight Carnauba wax (A): 5 parts by weight

(Example of production of transparent toner 17)
100 parts of water, aqueous dispersion of vinyl resin (styrene salt copolymer of styrene-methacrylic acid-butyl acrylate-methacrylic acid ethylene oxide adduct sulfate) (manufactured by Sanyo Chemical Industries, solid content 20%) 10 parts, 20 parts of 50% aqueous solution of sodium dodecyl diphenyl ether disulfonate (Eleminol MON-7, manufactured by Sanyo Chemical Co., Ltd.), 1% of carboxymethyl cellulose (cellogen BSH, manufactured by Sanyo Chemical Industries, Ltd.) as a polymer protective colloid 40 parts of the aqueous solution and 15 parts of ethyl acetate were mixed and stirred to obtain a milky white liquid. This is the aqueous phase.

  A container equipped with a stir bar and a thermometer was charged with 230 parts of polyester resin (I), 40 parts of crystalline polyester resin (A), 40 parts of carnauba wax (A), and 200 parts of ethyl acetate, and stirred at 80 ° C. The mixture was kept at 80 ° C. for 5 hours, cooled to 30 ° C. over 1 hour, and using a bead mill (Ultra Visco Mill, manufactured by IMEX Co., Ltd.), the liquid feeding speed: 1.2 Kg / The wax was dispersed under the conditions of hr, disk peripheral speed: 10 m / sec, 0.5 mm zirconia bead filling amount: 80 vol%, and the number of passes: 5 times to obtain a wax dispersion. The polyester resin (I) has a Tg of 64.0 ° C., Mw of 15300, Mn of 3800, an acid value of 7.0 mgKOH / g, and a tangent loss peak temperature of 143.7 ° C.

  1250 parts of the aqueous phase, 1130 parts of the wax dispersion, 1 part of isobutyl alcohol, 7 parts of isophorone diamine, and 5 parts of an emulsion stabilizer UCAT660M (manufactured by Sanyo Chemical Industries Ltd.) are placed in a container. The mixture was mixed at 9,000 rpm for 30 minutes using a mixer (manufactured by PRIMIX Corporation) to obtain an aqueous medium dispersion. Thereafter, the aqueous medium dispersion was heated to 58 ° C. and further dispersed and mixed at a rotation speed of 1,500 rpm for 1 hour using a TK homomixer to obtain an emulsified slurry.

  The emulsified slurry was put into a container equipped with a stirrer and a thermometer, and after removing the solvent at 35 ° C. for 10 hours, aging was carried out at 45 ° C. for 12 hours to obtain a dispersion from which the organic solvent was distilled off. After filtering 100 parts of the dispersion under reduced pressure, 300 parts of ion-exchanged water was added to the filter cake, and the mixture was stirred for 15 minutes at 6,000 rpm using a TK homomixer, and then filtered under reduced pressure. Thereafter, 100 parts of a 10% aqueous sodium hydroxide solution was added to the filter cake, and the mixture was stirred for 15 minutes at a rotational speed of 6,000 rpm using a TK homomixer, and then filtered under reduced pressure. Thereafter, 100 parts of 10% hydrochloric acid was added to the filter cake, and the mixture was stirred for 15 minutes at 6,000 rpm using a TK homomixer TK homomixer, followed by filtration under reduced pressure. Thereafter, 500 parts of ion-exchanged water was added to the filter cake, and the mixture was stirred for 30 minutes at a rotational speed of 6,000 rpm using a TK homomixer, and then filtered under reduced pressure to obtain a filter cake.

  The above filter cake was dried at 40 ° C. for 24 hours with a circulating dryer, and sieved with a mesh having a mesh size of 75 μm to obtain toner base particles. Next, 1.0 part by weight of an additive (HDK-2000, manufactured by Clariant Co., Ltd.) was stirred and mixed with 100 parts by mass of the toner base particles with a Henschel mixer to produce a transparent toner 17.

(Example of production of transparent toners 18 to 27)
Adjusting the particle size distribution by adjusting the louver opening of the air classifier (manufactured by Nippon Pneumatic Industry Co., Ltd., MDS-I) as appropriate, or by intentionally blending the fine powders separated during classification Transparent toners 17 to 27 were produced in the same manner as the transparent toner 13 except that.

 The weight average particle diameter (μm), the ratio of particles having a particle diameter of 4 μm or less (number%), and the ratio of particles having a particle diameter of 8 μm or more (volume%) of the transparent toner 1 to the transparent toner 27 obtained by the above transparent toner production example , Ratio of particles having a particle size of 10.08 μm or more (volume%), tangent loss peak temperature (° C.), tangent loss, maximum value and minimum value of storage elastic modulus (G ′) in the range of 120 to 160 ° C. ( Pa), differential nickname value (Pa) of the storage elastic modulus (G ′) in the range of 70 to 90 ° C., presence of crystalline polyester resin, lubricant (whether WAX is present, amide based lubricant is present) The results are summarized in Table 1 below.

(Example of color toner production)
[Example of master batch production]
Add 50 parts of carbon black (Cabot, Regal 400R), 50 parts of polyester resin (Sanyo Chemical Industries, RS801), 30 parts of water and mix with a Henschel mixer (Mitsui Mining). This roll was kneaded at 160 ° C. for 50 minutes, then rolled and cooled, and pulverized with a pulverizer to obtain a black master batch (1).
In addition, C.I. I. Pigment Red 269, C.I. I. Pigment Blue 15: 3, C.I. I. A magenta master batch (1), a cyan master batch (1), and a yellow master batch (1) were prepared in the same manner except that Pigment Yellow 155 was used instead of carbon black.

[Black toner production example]
A black toner (1) was produced in the same manner as the transparent toner 1 except that the raw material having the following black toner formulation was used.
<Prescription of black toner>
Polyester resin (J): 100 parts by weight [Tg; 64.2 ° C., Mw; 15300, Mn; 3800, acid value 7.0 mgKOH / g,
Tangent loss peak temperature; 144.0 ° C]
Crystalline polyester resin (A): 15 parts by weight Carnauba wax (A): 4 parts by weight Stearic acid amide (A): 2 parts by weight Black masterbatch (1): 16 parts by weight

[Production examples of magenta toner, cyan toner, yellow toner]
The magenta masterbatch (1), the cyan masterbatch (1), and the yellow masterbatch (1) are respectively used in place of the black masterbatch (1) in the toner raw material formulation black, and magenta Toner (1), cyan toner (1), and yellow toner (1) were produced.

Example 1
Transparent toner 1 prepared in Transparent Toner Production Example 1 and each 5% by mass of each color toner prepared in Color Toner Production Example and 95% by mass of coated ferrite carrier were prepared by Turbler Mixer (Willy et Bacofen (WAB)). ) And uniformly charged at 48 rpm for 5 minutes to charge the transparent toner developer (1), black developer (1), magenta developer (1), cyan developer (1), and yellow developer (1). Produced.

The transparent toner developer (1) is accommodated in the developing unit 105E of the electrophotographic developing apparatus shown in FIG. 5, and the developing units 105A to 105D each have a yellow developer (1), a magenta developer (1), and a cyan developer. (1) A black developer (1) was accommodated.
Transparent toner and chromatic toner were output using an image forming apparatus containing each developer. On the solid image of the color toner adhesion amount 0.4 mg / cm ^2, as a solid image of the transparent toner amount 0.4 mg / cm ² overlap, exposure, development, transfer, and the linear velocity of the fixing 160 mm / After fixing at a second, a fixing temperature of 190 ° C., and an NIP width of 11 mm, the glossiness of the image was measured. The thickness of the toner layer of the transparent toner after fixing was 7 μm. Further, a development chart is used as it is so that the thickness of the transparent toner layer does not change, and a character chart (1% of the image area of the transparent toner on the solid image of the color toner having an adhesion amount of 0.4 mg / cm ² is separately provided (1). The character size was about 2 mm × 2 mm) and was used for evaluation of the fineness of the transparent toner image. For evaluation, POD gloss coated paper 128 g / m ² made by Oji Paper was used.
The evaluation conditions and evaluation criteria for each evaluation item [fixability (low-temperature fixability, hot offset resistance), storage stability, glossiness, image definition of transparent toner) are as follows.

<Fixability>
The cold offset temperature (fixing lower limit temperature) and the hot offset temperature (hot offset resistant temperature) were determined by changing the fixing temperature. The criteria for each characteristic evaluation are as follows.
[Low temperature fixability]
◎: Less than 130 ° C ○: 130-140 ° C
□: 140-150 ° C
Δ: 150-160 ° C
×: 160 ° C or higher [Hot offset resistance]
◎: 201 ℃ or higher ○: 191 ～ 200 ℃
□: 181 to 190 ° C
Δ: 171 to 180 ° C
×: 170 ° C. or less

<Preservability>
10 g of each toner was put in a 30 ml screw vial, tapped 100 times with a tapping machine, stored in a constant temperature bath at 45 ° C. for 24 hours, returned to room temperature, and then measured for penetration with a penetration tester. It was set as heat resistant storage evaluation.
When the penetration is 10 mm or less, ×, 10-15 mm are △, 15-20 mm are ◯, and 20 mm or more are ◎.

<Glossiness>
Using the transparent toner image output as the above solid image, gloss was evaluated at 10 locations with a gloss of 60 degrees using a gloss meter VGS-1D manufactured by Nippon Denshoku Industries Co., Ltd., and the average gloss was 80 or more. 80 was evaluated as ◯, 40-60 as Δ, and 40 or less as X.

<Image definition of transparent toner>
The fineness of the image was evaluated from the character reproducibility of the character chart with the image area of 5% (the size of one character is about 2 mm × 2 mm). The ranking of evaluation was performed as follows.
◎: Very good, ○: Good, △: Acceptable, ×: Unusable level for practical use

(Comparative Example 1)
Evaluation was performed in the same manner as in Example 1 except that the transparent toner 2 prepared in Toner Production Example 2 was used as the transparent toner.

(Example 2)
Evaluation was performed in the same manner as in Example 1 except that the transparent toner 3 prepared in Toner Production Example 3 was used as the transparent toner.

(Comparative Example 2)
Evaluation was performed in the same manner as in Example 1 except that the transparent toner 4 prepared in Toner Production Example 4 was used as the transparent toner.

(Comparative Example 3)
Evaluation was performed in the same manner as in Example 1 except that the transparent toner 5 prepared in Toner Production Example 5 was used as the transparent toner.

(Example 3)
Evaluation was performed in the same manner as in Example 1 except that the transparent toner 6 prepared in Toner Production Example 6 was used as the transparent toner.

(Comparative Example 4)
Evaluation was performed in the same manner as in Example 1 except that the transparent toner 7 prepared in Toner Production Example 7 was used as the transparent toner.

Example 4
Evaluation was performed in the same manner as in Example 1 except that the transparent toner 8 prepared in Toner Production Example 8 was used as the transparent toner.

(Comparative Example 5)
Evaluation was performed in the same manner as in Example 1 except that the transparent toner 9 prepared in Toner Production Example 9 was used as the transparent toner.

(Example 5)
Evaluation was performed in the same manner as in Example 1 except that the transparent toner 10 prepared in Toner Production Example 10 was used as the transparent toner.

(Example 6)
Evaluation was performed in the same manner as in Example 1 except that the transparent toner 11 prepared in Toner Production Example 11 was used as the transparent toner.

(Example 7)
Evaluation was performed in the same manner as in Example 1 except that the transparent toner 12 prepared in Toner Production Example 12 was used as the transparent toner.

(Example 8)
Evaluation was performed in the same manner as in Example 1 except that the transparent toner 13 prepared in Toner Production Example 13 was used as the transparent toner.

Example 9
Evaluation was performed in the same manner as in Example 1 except that the transparent toner 14 prepared in Toner Production Example 14 was used as the transparent toner.

(Comparative Example 6)
Evaluation was conducted in the same manner as in Example 1 except that the transparent toner 15 prepared in Toner Production Example 15 was used as the transparent toner.

(Comparative Example 7)
Evaluation was performed in the same manner as in Example 1 except that the transparent toner 16 prepared in Toner Production Example 16 was used as the transparent toner.

(Example 10)
Evaluation was performed in the same manner as in Example 1 except that the transparent toner 17 prepared in Toner Production Example 17 was used as the transparent toner.

(Example 11)
Evaluation was performed in the same manner as in Example 1 except that the transparent toner 18 prepared in Toner Production Example 18 was used as the transparent toner.

(Example 12)
Evaluation was performed in the same manner as in Example 1 except that the transparent toner 19 prepared in Toner Production Example 19 was used as the transparent toner.

(Example 13)
Evaluation was performed in the same manner as in Example 1 except that the transparent toner 20 prepared in Toner Production Example 20 was used as the transparent toner.

(Example 14)
Evaluation was performed in the same manner as in Example 1 except that the transparent toner 21 prepared in Toner Production Example 21 was used as the transparent toner.

(Example 15)
Evaluation was performed in the same manner as in Example 1 except that the transparent toner 22 prepared in Toner Production Example 22 was used as the transparent toner.

(Example 16)
Evaluation was performed in the same manner as in Example 1 except that the transparent toner 23 prepared in Toner Production Example 23 was used as the transparent toner.

(Example 17)
Evaluation was performed in the same manner as in Example 1 except that the transparent toner 24 prepared in Toner Production Example 24 was used as the transparent toner.

(Example 18)
Evaluation was performed in the same manner as in Example 1 except that the transparent toner 25 prepared in Toner Production Example 25 was used as the transparent toner.

(Example 19)
Evaluation was performed in the same manner as in Example 1 except that the transparent toner 26 prepared in Toner Production Example 26 was used as the transparent toner.

(Example 20)
Evaluation was performed in the same manner as in Example 1 except that the transparent toner 27 prepared in Toner Production Example 27 was used as the transparent toner.

(Example 21)
Evaluation was performed in the same manner as in Example 1 except that the solid image adhesion amount with the transparent toner 13 was 0.05 mg / cm ² . The thickness of the toner layer of the transparent toner after fixing was 0.5 μm.

(Example 22)
Evaluation was performed in the same manner as in Example 1 except that the amount of the solid image adhered to the transparent toner 13 was 0.1 mg / cm ² . The thickness of the toner layer with the transparent toner after fixing was 2 μm.

(Example 23)
Evaluation was performed in the same manner as in Example 1 except that the amount of the solid image adhered to the transparent toner 13 was 1.2 mg / cm ² . The thickness of the toner layer of the transparent toner after fixing was 14 μm.

(Example 24)
Evaluation was performed in the same manner as in Example 1 except that the solid image adhesion amount with the transparent toner 13 was 1.5 mg / cm ² . The thickness of the toner layer of the transparent toner after fixing was 16 μm.

(Example 25)
Evaluation was performed in the same manner as in Example 1 except that the solid layer image of the color toner was formed on the solid image of the transparent toner. The image definition of the transparent toner was confirmed by outputting only the transparent toner image without forming a solid image of color toner.

   The evaluation results of Examples 1 to 25 and Comparative Examples 1 to 7 are shown in Table 2 below. The transparent toner used, the outermost toner, and the thickness of the transparent toner layer are also shown in Table 2.

As is clear from Table 2, in each of Examples 1 to 25, both low-temperature fixability, high hot offset resistance, and storage stability (storage stability or storage stability) are compatible, and fine and high gloss. It can be seen that the image can be formed. On the other hand, in Comparative Examples 1 to 7, an evaluation judgment of “x” is included in at least one of the fixability (low-temperature fixability, hot offset resistance), storage stability, glossiness, and image definition of the transparent toner. In other words, the object of the present invention cannot be achieved in a well-balanced manner and cannot be actually used.
That is, the transparent toner for electrophotographic development that can achieve the low-temperature fixing property, high hot offset resistance and storage stability of the present invention and can form a fine and high-gloss image is used as an electronic device such as a copying machine, a laser printer, or a facsimile machine. By using it in the photographic process, it becomes possible to meet demands for energy saving, higher image forming processing speed, higher image quality, and the like.

(Reference numerals of FIGS. 2, 3 and 4)
DESCRIPTION OF SYMBOLS 1 Paper 2 Cellulose fiber 3 Toner layer 4 Chromatic color toner layer 5 Transparent toner layer (reference numeral in FIG. 5)
DESCRIPTION OF SYMBOLS 101A Drive roller 101B Follower roller 102 Photoconductor belt 103 Charger 104 Laser writing system unit 105A-105D Development unit which accommodates each color toner of yellow, magenta, cyan, and black 105E Development unit which accommodates transparent toner 106 Paper feed Cassette 107 Intermediate transfer belt 107A Drive shaft roller 107B for driving the intermediate transfer belt 107B Driven shaft roller for supporting the intermediate transfer belt 108 Cleaning device 109 Fixing roller 109A Pressure roller 110 Paper discharge tray 113 Paper transfer roller (reference numeral in FIG. 6)
DESCRIPTION OF SYMBOLS 20 Photosensitive drum 21 Toner 23 Carrier 40 Developing apparatus 41 Developing sleeve 42 Developer accommodating member 43 Doctor blade (Developer supply regulation member)
44 Support case 45 Toner hopper 46 Developer container 47 Developer stirring mechanism 48 Toner agitator 49 Toner replenishment mechanism (reference numeral in FIG. 7)
20 Photosensitive drum 32 Image carrier charging member [charging member]
33 Image Exposure System 40 Developing Device 41 Developing Sleeve 45 Toner Hopper 47 Developer Stirring Mechanism 50 Transfer Mechanism [Transfer Device]
60 Cleaning mechanism [Cleaning device]
61 Cleaning blade 62 Toner recovery chamber 70 Static elimination lamp 80 Transfer medium (reference numeral in FIG. 8)
DESCRIPTION OF SYMBOLS 20 Photoconductor 24a Drive roller 24b Drive roller 26 Exposure light source before cleaning 32 Charging member 33 Image exposure system 40 Developing device 50 Transfer device [transfer mechanism]
61 Cleaning blade 64 Brush-like cleaning means 70 Static elimination lamp (reference numeral in FIG. 9)
20 Photosensitive member 32 Brush-like contact charging means [charging means]
40 Developing means [Developing device]
61 Cleaning blade [cleaning blade means]

JP-A-4-278967 JP-A-4-362960 (Patent No. 3146367) Japanese Patent Laid-Open No. 9-200551 JP-A-5-158364 Japanese Patent Laid-Open No. 8-220821 (Japanese Patent No. 2750105) JP 2009-109926 A JP-A-4-338984 (Patent No. 3030576) JP 62-63940 A JP 2003-167384 A (Patent No. 3949553) Japanese Patent No. 3168366

Claims (13)

A transparent toner for electrophotographic development used for forming a transparent toner image on a recording medium,
The toner includes a binder resin, a crystalline polyester resin, and a lubricant as a component of the toner, and a peak value of tangent loss obtained by evaluating viscoelasticity of the toner and calculated by the following formula (1) is 80 to 160 [ ° C], the peak value of the tangent loss is 3 or more, and the storage elastic modulus (G ′) shown in the formula (1) is 1 [Pa] or more at 120 to 160 [° C], 1. A transparent toner for electrophotographic development, which is 1 × 10 ⁴ [Pa] or less.
Loss modulus (G ″) / Storage modulus (G ′) = tangent loss (tan δ) (1)   The transparent toner has a weight average particle size (Mw) of 3 to 8 μm, and in the particle size distribution, the proportion of particles of 4 μm or less is 10 to 70% by number, the proportion of particles of 8 μm or more is 1 to 20% by volume, 10 The transparent toner for electrophotographic development according to claim 1, wherein the ratio of particles having a particle size of 0.08 μm or more is 6% by volume or less. 3. The transparent toner for electrophotographic development according to claim 1, wherein the storage elastic modulus (G ′) is 1 × 10 ⁵ [Pa] or more at 70 to 90 ° C. ³ .   The lubricant comprises at least one selected from a higher aliphatic alcohol / higher fatty acid lubricant, a fatty acid amide lubricant, an aliphatic hydrocarbon lubricant, a metal soap lubricant, and a fatty acid ester lubricant. Item 4. The transparent toner for electrophotographic development according to any one of Items 1 to 3.   5. The transparent toner for electrophotographic development according to claim 1, wherein the lubricant contains a higher aliphatic alcohol / higher fatty acid lubricant.   The transparent toner for electrophotographic development according to any one of claims 1 to 4, wherein the lubricant contains a fatty acid amide-based lubricant.   The transparent toner for electrophotographic development according to claim 6, wherein the fatty acid amide-based lubricant is contained at least in the toner.   The transparent toner for electrophotographic development according to claim 6 or 7, wherein the fatty acid amide lubricant is N, N'-ethylene-bisstearic acid amide.   A step of charging at least the surface of the image carrier and a step of developing the electrostatic latent image formed on the charged image carrier using the transparent toner for electrophotographic development according to any one of claims 1 to 7. And a step of transferring the transparent toner image formed on the image carrier onto a recording medium, and a fixing step of fixing the transparent toner image transferred onto the recording medium by a fixing member. Image forming method.   And a step of forming a color image on the recording medium using one or more kinds of chromatic color toners, and a step of forming a transparent toner image using the transparent toner for electrophotographic development. Item 10. The electrophotographic image forming method according to Item 9.   11. The electrophotographic image forming method according to claim 9, wherein a layer thickness of the transparent toner image after fixing is 1 to 15 μm.   12. The electrophotographic image forming method according to claim 9, wherein at least one layer of the transparent toner image is formed on an outermost surface of a recording medium on which the image is fixed.   At least an image carrier and development means for making at least an electrostatic latent image formed on the image carrier a visible image using a toner or a developer composed of toner and a carrier. 9. A process cartridge, wherein the toner is a transparent toner for electrophotographic development according to any one of claims 1 to 8.

Images