JP2014056047A - Electrophotographic toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic transparent toner that is used in an ultra high-speed print system capable of supporting a print-on-demand (POD) field in particular, and has excellent low-temperature fixability and heat-resistance storage stability, in a method of forming an image using an electrophotographic transparent toner for forming different glossinesses on the same recording target medium.SOLUTION: An electrophotographic transparent toner contains at least a crystalline polyester; and toner particles of the toner include silica in which a plurality of primary particles are joined to each other to form a secondary particle.

Description

  The present invention relates to a chromatic color toner image and a transparent toner image for visualizing an electrostatic charge latent image formed on the surface of an image carrier, and is particularly applicable to the field of print on demand (POD) utilizing an electrophotographic method. The present invention relates to a chromatic toner, a transparent toner, and a developer using the chromatic toner for obtaining a high-gloss image suitable for an ultra-high speed printing system.

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 addition, there is a great demand for higher image quality, and in response to a demand for high-quality image formation such as photographic images, it is possible to provide a clear high-gloss image by imparting gloss to the surface of a recording medium such as recording paper. Are known.

In an electrophotographic method used in an image forming apparatus such as a laser printer or a dry electrostatic copying machine, for example, by arranging a transparent toner in addition to a chromatic toner, a portion of the chromatic toner on the medium and a chromatic toner For example, a method of eliminating a difference in glossiness from an unexposed portion or disposing a transparent toner on the entire surface of a recording medium is used. (Patent Document 1, Patent Document 2, Patent Document 3)
Also disclosed is an apparatus for forming a high-gloss image on the entire surface of a recording medium by heating and melting a recording medium on which a chromatic toner and a transparent toner image are formed using a fixing device and then cooling and peeling the recording medium. (Patent Document 4) According to these methods, it is possible to eliminate a gloss difference on the entire surface of a recording medium and provide a uniform gloss.

  As a method of forming different glossiness on the same recording medium by the electrophotographic method, a method of controlling glossiness by adjusting the number average molecular weight of the resin used for the toner (Patent Document 5), a transparent toner after fixing the colored toner, A method for forming a toner image, lowering the fixing temperature and lowering gloss (Patent Document 6) has been proposed, and further, a method for printing and fixing a glossy range at the first time, and printing and fixing a non-glossy region at the second time. Is disclosed (Patent Document 7). According to these methods, it is possible to obtain different glossiness on the same recording medium, however, high spot glossiness similar to photographic glossiness as performed with spot varnish has not yet been realized.

As described above, there are various methods for controlling glossiness on a recording medium using a transparent toner. For example, Patent Document 5 uses a polyester resin having a number average molecular weight of about 3500 as a transparent toner, and a chromatic color. A polyester resin having a number average molecular weight of about 10,000 is used for the toner. The transparent toner has a lower melting point than that of the chromatic toner, so that the smoothness is improved and the glossiness of the transparent toner portion is partially increased. It is disclosed that there is.
However, since the transparent toner is formed on the uppermost layer of the image and directly contacts the fixing machine, higher hot offset resistance than that of the chromatic toner is required and the transparent toner is formed on the chromatic toner image. The combination of the low melting point transparent toner and the high melting point chromatic color toner is not stable unless the toner layer becomes thick and the chromatic color toner has a characteristic having a high cold offset property.

On the other hand, when a toner has high hot offset resistance, it is generally performed to prevent hot offset by introducing a crosslinking monomer into the resin used to widen the molecular weight distribution.
However, when a cross-linking monomer is introduced, hot offset can be prevented particularly in an ultra-high speed printing system that can cope with the field of print on demand (POD), but fluidity does not appear due to the influence of elastic components, and the toner image. There was a problem that the smoothness of the surface was impaired, the gloss was lowered, and a cold offset occurred.

Further, in the method described in Patent Document 6, the ultimate melt viscosity of the toner in the fixing nip at the time of the second image formation is set larger than that in the fixing nip at the time of the first image formation. Since the transparent toner image formed at the time of image formation does not melt sufficiently, the gloss is lowered.
Further, in the image forming method described in Patent Document 7, it is disclosed that a transparent toner resin can be a thermoplastic resin such as a styrene-acrylic copolymer or a polyester resin, or a thermosetting resin. The construction of the toner for producing gloss is not disclosed.

There are various methods for producing a transparent toner for electrophotography, which will be described.
The toner obtained by the conventional kneading and pulverization method is difficult to reduce the particle size, the toner particle shape is irregular, the particle size distribution is broad, and the fixing energy is high. was there. In particular, with respect to fixing, a toner produced by a kneading pulverization method is cracked at the interface of a release agent (wax) during pulverization, so that a large amount of wax is present on the surface of the toner particles.
For this reason, while the releasing effect is produced, the toner easily adheres to the carrier, the photoreceptor and the blade, and the overall performance is not satisfactory. Even transparent toners are not satisfactory in that the particle size distribution is non-uniform.

On the other hand, in order to overcome the above-described problems caused by the kneading and pulverizing method, a method for producing a toner by a chemical method has been proposed.
The toner produced by such a chemical method can be easily reduced in particle size, the particle size distribution is sharper than the particle size distribution of the toner obtained by the pulverization method, and can also contain wax.

As a method for producing a toner by such a chemical method, it is produced from an elongation reaction product of a urethane-modified polyester as a toner binder for the purpose of improving the fluidity of the toner, improving the low-temperature fixability, and improving the hot offset property. In addition, a method for producing a toner having a practical sphericity of 0.90 to 1.00 is disclosed (see, for example, Patent Document 8).
Also disclosed is a method for producing a toner that is excellent in powder flowability and transferability in the case of a small particle size toner and excellent in all of heat-resistant storage stability, low-temperature fixability and hot offset resistance (for example, And Patent Documents 9 and 10). However, the transparent toner produced by this production method does not satisfy the heat-resistant storage stability because there is no colorant.

  The problem to be solved by the present invention is to form different glossiness on the same recording medium, so that the method of forming an image using transparent toner for electrophotography can be applied to the field of print on demand (POD). Another object of the present invention is to provide a transparent toner for electrophotography which is used in a super high speed printing system and has excellent low-temperature fixability and heat-resistant storage stability.

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 (9), and have reached the present invention. Hereinafter, the present invention will be specifically described.
(1) “Transparent toner for electrophotography containing at least crystalline polyester, wherein toner particles include silica in which a plurality of primary particles are fused to form secondary particles. `` Transparent toner for electrophotography '',
(2) “The average coalescence degree G of silica in which a plurality of primary particles are coalesced to form secondary particles is 1.5 to 4.0. Transparent toner for electrophotography.
However, the adhesion degree G is defined by the following formula (1) where the silica primary particle diameter is D1 and the secondary particle diameter is D2.
Degree of adhesion G = D2 / D1 (Expression 1) ",
(3) “obtained by emulsifying and dispersing an oil phase obtained by dissolving and dispersing at least crystalline polyester and silica forming the secondary particles in an organic solvent in an aqueous medium containing a fine particle dispersant. The transparent toner for electrophotography according to item (1) or (2), wherein the toner is
(4) "The transparent toner for electrophotography according to any one of (1) to (3) above, wherein an average secondary particle diameter Db of the silica is 80 nm to 200 nm",
(5) "The transparent toner for electrophotography according to any one of (1) to (4) above, wherein the silica is contained in the oil phase",
(6) “After containing a binder resin component precursor composed of a modified polyester resin in the oil phase and dissolving the binder resin component precursor and a compound that extends or crosslinks, finely disperse the oil phase. Obtained by dispersing in an aqueous medium in which an agent is present to obtain an emulsified dispersion, causing the binder resin component precursor to undergo a crosslinking reaction and / or elongation reaction in the emulsified dispersion, and removing the organic solvent. The transparent toner for electrophotography according to any one of items (1) to (5), wherein:
(7) “The transparent toner for electrophotography according to any one of (1) to (6) above, wherein the toner contains 2 to 20% by weight of the crystalline polyester resin”. ,
(8) “The transparent toner for electrophotography according to any one of (1) to (7) above, wherein the crystalline polyester has a melting point of 55 to 85 ° C.”,
(9) “A toner set combining a transparent toner for electrophotography and a chromatic toner, wherein the transparent toner for electrophotography contains at least a crystalline polyester, and the toner particles of the transparent toner include a plurality of primary particles. A toner set comprising a combination of a transparent toner for electrophotography and a chromatic toner, characterized in that it comprises silica that is bonded individually to form secondary particles.

  According to the present invention, there is provided a high gloss electrophotographic transparent toner capable of forming different glossiness on the same recording medium in an image forming apparatus and having excellent low-temperature fixability and heat-resistant storage stability. Can do.

It is a figure explaining the secondary particle diameter of the silica fine particle in this invention. It is a figure explaining the primary particle diameter of the silica fine particle in this invention. 1 is a front view showing a form of an image forming apparatus A. FIG. 2 is a front view showing a form of an image forming apparatus B. FIG. It is a graph which shows the DSC measurement example of crystalline polyester.

Next, the form for implementing this invention is demonstrated in detail with drawing.
The present invention is an electrophotographic transparent toner containing at least a crystalline polyester, and it is important that the toner particles contain and contain silica in which a plurality of primary particles are coalesced to form secondary particles. is there.
By introducing the crystalline polyester, the viscoelasticity of the toner can be sharply reduced, and the low temperature fixability can be improved without greatly deteriorating the heat resistant storage stability.
However, in the case of the transparent toner, since the colorant is not contained in the chromatic color toner, the viscoelasticity of the surface of the transparent toner is low, and the heat resistant storage stability is inferior to that of the chromatic color toner.
Therefore, in the present invention, for example, an oil phase obtained by dissolving and dispersing a release agent and crystalline polyester in an organic solvent is obtained by emulsifying and dispersing in an aqueous medium containing a fine particle dispersant in the form of droplets. In the toner production method, silica is contained in an oil phase, and toner granulation is performed in an aqueous medium. As a result, the silica can be moved from the inside of the oil phase droplet toward the surface side in contact with the aqueous medium, the silica can be disposed on the surface of the transparent toner particles, the viscoelasticity of the toner particle surface can be increased, and heat resistance can be increased. Preservability can be increased. In addition, since silica can be partially exposed on the toner particle surface, the fluidity of the transparent toner can be exemplified.
Thereby, it is possible to provide a transparent toner for electrophotography having both low-temperature fixability and heat-resistant storage stability.

As silica, silica in which a plurality of primary particles are fused to form secondary particles is preferable. Further, silica having an average coalescence degree G of 1.5 to 4.0 is preferable. The degree of coalescence G is defined by the following formula where the silica primary particle diameter is D1 and the secondary particle diameter is D2.
Degree of adhesion G = D2 / D1 (Formula 1)
When the average adhesion degree is less than 1.5, it is close to a sphere and cannot be exposed in the vicinity of the toner surface or a part thereof, which tends to cause insufficient fluidity and deterioration in heat storage stability. On the other hand, when the average degree of adhesion exceeds 4.0, the toner particle surface exposure increases, the external additive is easily peeled off from the toner, and carrier contamination and the photoreceptor are damaged. Become. Therefore, silica having an average adhesion degree G of 1.5 to 4.0 is desirable.

  Furthermore, it is desirable that the secondary particle diameter of the fused silica be in the range of 80 nm to 200 nm. If it is less than 80 nm, the function of increasing the viscosity of the toner surface cannot be achieved, and the heat resistant storage stability is deteriorated. On the other hand, if it exceeds 200 nm, release from the toner is unavoidable, and there is a concern of causing photoconductor filming.

The content of the crystalline polyester in the transparent toner is preferably 2 to 20% (mass (weight)%, the same unless otherwise specified). If it is less than 2%, the contribution of the transparent toner to low-temperature fixing and gloss is small, which is not preferable. Further, when it exceeds 20%, the viscosity of the oil phase during toner production is remarkably increased and granulation is difficult. Therefore, 2 to 20% is preferable as the crystalline polyester.
Moreover, as content of the silica contained in an oil phase, 0.1 to 3% is preferable. If it is less than 0.1%, the amount of silica present on the surface of the transparent toner particles is too small, and the viscoelasticity of the toner surface cannot be increased. On the other hand, if it exceeds 3%, the amount existing or exposed on the toner surface increases, and as a result, there is a possibility of adversely affecting the low-temperature fixability. Therefore, the silica content contained in the oil phase is preferably 0.1 to 3%.

The fused silica contained in the toner used in the present invention is prepared by chemically bonding primary particles of crystalline silica and / or fused silica using a treating agent. , Silane coupling agents, silane treatment agents such as chlorosilanes and silazanes, or epoxy treatment agents such as liquid epoxy resins are preferably used.
When silica primary particles are treated with a silane treatment agent such as alkoxysilanes or silane coupling agents, silanol groups bonded to the silica primary particles react with alkoxy groups bonded to the silane treatment agent. Then, a new Si—O—Si bond is formed by dealcoholization.
That is, as shown in the following formula, the silica primary particles are secondarily aggregated by chemical bonding via the silane-based treatment agent.

When the silica primary particles are treated with chlorosilanes, the chloro group of the chlorosilanes and the silanol group bonded to the silica primary particles form a new Si-O-Si bond by the dehydrochlorination reaction. When coexisting with water, chlorosilanes first hydrolyze into water to form silanol groups, and the silanol groups and the silanol groups bonded to the silica primary particles are each subjected to a new Si-O-Si bond by a dehydration reaction. To produce secondary agglomeration.
Silazanes form a new Si—O—Si bond and secondary agglomerate when the amino group and the silanol group bonded to the silica primary particles are deammoniated.
On the other hand, when silica primary particles are treated with an epoxy-based treatment agent, silanol groups bonded to the silica primary particles add an epoxy group oxygen atom of the epoxy-based treatment agent and a carbon atom bonded to the epoxy group. Then, a new Si—O—C bond is formed.
That is, as shown in the following formula, the silica primary particles are secondarily aggregated by a chemical bond via an epoxy-based treatment agent.

  The fused silica used in the present invention is prepared by preparing silica as primary particles, and then preparing fused silica by treating the silica with the above-described silane-based treatment agent or epoxy-based treatment agent to fill the epoxy resin. However, for example, when silica is synthesized by a sol-gel method, a fused silica may be prepared by a one-step reaction in the presence of the silane-based treatment agent or epoxy-based treatment agent.

In addition, since the Si—O—Si bond to be produced is more stable to heat than the Si—O—C bond, the silane-based treatment agent is preferable to the epoxy-based treatment agent. .
Specific examples of alkoxysilanes that are the silane-based treatment agents include tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, methyldimethoxysilane, Examples include methyldiethoxysilane, diphenyldimethoxysilane, isobutyltrimethoxysilane, and decyltrimethoxysilane.

  Specific examples of the silane coupling agent that is the silane treatment agent include γ-aminopropyltolethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-glycidoxypropylmethyldiethoxy. Examples include silane, γ-methacryloxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, vinyltriethoxysilane, and methylvinyldimethoxysilane.

  Furthermore, as silane-based treatment agents other than the above alkoxysilanes or silane-based coupling agents, specifically, vinyltrichlorosilane, dimethyldichlorosilane, methylvinyldichlorosilane, methylphenyldichlorosilane, phenyltrichlorosilane, N , N′-bis (trimethylsilyl) urea, N, O-bis (trimethylsilyl) acetamide, dimethyltrimethylsilylamine, hexamethyldisilazane, cyclic silazane mixture and the like.

  Specific examples of the epoxy-based treatment agent include bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolak type epoxy resin, biphenol type epoxy resin, Examples thereof include glycidylamine type epoxy resins and alicyclic epoxy resins.

The fused silica used in the present invention is prepared by chemically bonding primary particles of crystalline silica and / or fused silica using the above-mentioned treatment agent. The treatment is performed by first combining the primary silica particles and the treatment agent. Mixing is performed at a weight ratio of 100: 0.01 to 100: 50 using a known mixer such as a spray dryer.
At that time, for example, water or a 1% aqueous acetic acid solution may be appropriately added as a processing aid.
The mixture of the silica primary particles and the treating agent is then fired, and the firing temperature is selected from a temperature range of 100 to 2500 ° C.
The firing time may be 0.5 to 30 hours.

The degree of coalescence of silica can be arbitrarily controlled by adjusting the primary particle diameter, the type and amount of the treatment agent, and the treatment conditions.
That is, the cohesive strength is stronger when a silane-based treatment agent is used than when an epoxy-based treatment agent is used, when the amount of the treatment agent is increased with respect to primary silica particles, and when the firing temperature is higher. And the degree of adhesion tends to be high. On the other hand, the proportion of non-fused particles can be reduced by extending the firing time. However, excessive time extension promotes agglomeration of the coalesced particles, which may cause a problem in adhesion to the toner.

(Measurement of degree of adhesion)
The measurement of the degree of adhesion is obtained by image observation. After the fused silica is dispersed in a suitable solvent (such as THF), the solvent is removed from the substrate and dried, and the sample is observed with an FE-SEM. The secondary particle diameter is measured for silica in the field of view at an acceleration voltage of 5 to 8 kV and an observation magnification of 8 to 10 k times.
Secondary particle size measures the longest length of aggregated particles. An example is shown in FIG. The number of silica to be observed is 100 or more particles.
Similarly, the primary particle diameter is observed with FE-SEM. The entire embedded image is predicted from the outer frame of the fused silica, and the longest length of the entire image is measured. An example is shown in FIG. Their average value is taken as the primary particle size. The number of silica to be observed is 100 or more particles.
Fig. 1 The length of the arrow is the secondary particle diameter.
Fig. 2 The average length of the arrows is taken as the primary particle size.
Degree of coalescence = secondary particle diameter / primary particle diameter.

In addition, a binder resin precursor made of a modified polyester resin is contained in the oil phase of the transparent toner, and after the compound that extends or crosslinks with the binder resin precursor is dissolved, the oil phase is used as a fine particle dispersant. It can be obtained by dispersing in an existing aqueous medium to obtain an emulsified dispersion, cross-linking reaction and / or elongation reaction of the binder resin precursor in the emulsified dispersion, and removing the organic solvent. Control of distribution is easy and preferable.
The volume average particle diameter Dv of the toner particles is preferably 3 μm or more and 7 μm or less, and the ratio of the volume average particle diameter to the number average particle diameter is preferably 1.3 or less. When Dv is less than 3 μm, the image quality is poor due to cleaning failure or the like. On the other hand, when the thickness exceeds 7 μm, the uniformity of the transparent toner is impaired, and unevenness of image gloss occurs. Similarly, if the ratio of the volume average particle diameter to the number average particle diameter exceeds 1.3, uneven image gloss occurs.

Furthermore, in the image forming apparatus used in the present invention, it is possible to obtain sufficient gloss even with a single fixing with an ultra-high-speed printing system with a linear speed of 300 to 2000 mm / sec that can be applied to the field of print on demand (POD). However, if it is desired to obtain a higher gloss, a latent image is formed, exposed and developed with a chromatic toner and a transparent toner in the first image formation, and then transferred to a recording medium. After fixing, the chromatic color toner can be latent image formed, exposed and developed in the second image formation, transferred to a recording medium, and then fixed on a fixing machine. Although the amount of toner is larger than the unformed part, the amount of heat can be sufficiently supplied by passing through the fixing machine twice, and the smoothness of the surface can be increased and high gloss can be obtained. In terms of sex, one fixing are preferred.
On the other hand, the glossiness of the chromatic color toner can be selected according to the purpose of use, but when the glossiness of the chromatic color toner is high, the glossiness of the transparent toner tends to be high, while the gloss difference on the recording medium is low.

In addition, when using a chromatic color toner having a low gloss, it is easy to increase the gloss difference on the recording medium, but it is difficult to obtain a high gloss even when a transparent toner is placed. This is because, in the case of a chromatic toner having a low gloss, the chromatic toner resin itself exerts a force to return to its original state due to viscoelasticity, so that the surface after fixing becomes slightly uneven.
When high glossiness is required as a whole, it is sufficient to use a chromatic toner having a small weight average molecular weight (Mw) / number average molecular weight (Mn). On the contrary, when low glossiness is required, A chromatic toner having a large weight average molecular weight (Mw) / number average molecular weight (Mn) may be selected.
When the gloss of chromatic color toner is low, thickening the transparent toner layer can cover the unevenness of the chromatic color toner to achieve high gloss, combining chromatic color toner with low gloss and transparent gloss toner with high gloss By adjusting the thickness of the transparent toner layer, it is possible to freely form images having different glossiness from low glossiness to high glossiness.

<Image Forming Method 1>
FIG. 3 shows the entire image forming apparatus A. As shown in FIG. First, the image forming method 1 will be described.
The image data sent to the image processing unit (hereinafter referred to as “IPU”) (14) is Y (yellow), M (magenta), C (cyan), Bk (black), and transparent image signals of five colors. Create
Next, Y, M, C, Bk, and transparent image signals are transmitted to the writing unit (15) in the image processing unit. The writing unit (15) modulates and scans five laser beams for Y, M, C, Bk, and transparency, and charges the photosensitive drum by the charging unit (51, 52, 53, 54, 55). After that, an electrostatic latent image is formed on each photosensitive drum (21, 22, 23, 24, 25) sequentially. Here, for example, the first photosensitive drum (21) is Bk, the second photosensitive drum (22) is Y, the third photosensitive drum (23) is M, and the fourth photosensitive drum ( 24) corresponds to C, and the fifth photosensitive drum (25) corresponds to transparency.
Next, a toner image of each color is formed on the photosensitive drum (21, 22, 23, 24, 25) by a developing unit (31, 32, 33, 34, 35) as a developing attachment means. Further, the transfer paper fed by the paper feed unit (16) is conveyed on the transfer belt (70), and the photosensitive drums (21, 21) are sequentially transferred by the transfer charges (61, 62, 63, 64, 65). 22, 23, 24, 25) are transferred onto the transfer paper.
After the transfer process is completed, the transfer paper is conveyed to a fixing unit (80), and the transferred toner image is fixed on the transfer paper by the fixing unit (80).
After the transfer process, the toner remaining on the photosensitive drum (21, 22, 23, 24, 25) is removed by the cleaning unit (41, 42, 43, 44, 45).

<Image Forming Method 2>
Next, the image forming method 2 in the case of partially producing high gloss will be described.
First, as in the image forming method 1, the image data sent to the image processing unit (hereinafter referred to as “IPU”) (14) is Y (yellow), M (magenta), C (cyan), Bk (black). Each image signal of five transparent colors is created.
Next, the first image formation with a partially high gloss is performed in the image processing unit. The Y, M, C, Bk, and transparent image signals of the portion that is partially highly glossy are transmitted to the writing unit (15). The writing unit (15) modulates and scans five laser beams for Y, M, C, Bk, and transparency, and charges the photosensitive drum by the charging unit (51, 52, 53, 54, 55). After that, an electrostatic latent image is formed on each photosensitive drum (21, 22, 23, 24, 25) sequentially. Here, for example, the first photosensitive drum (21) is Bk, the second photosensitive drum (22) is Y, the third photosensitive drum (23) is M, and the fourth photosensitive drum ( 24) corresponds to C, and the fifth photosensitive drum (25) corresponds to transparency.
Next, a toner image of each color is formed on the photosensitive drum (21, 22, 23, 24, 25) by a developing unit (31, 32, 33, 34, 35) as a developing attachment means. Further, the transfer paper fed by the paper feed unit (16) is conveyed on the transfer belt (70), and the photosensitive drums (21, 21) are sequentially transferred by the transfer charges (61, 62, 63, 64, 65). 22, 23, 24, 25) are transferred onto the transfer paper.
After the transfer process is completed, the transfer paper is conveyed to a fixing unit (80), and the transferred toner image is fixed on the transfer paper by the fixing unit (80).
After the transfer process, the toner remaining on the photosensitive drum (21, 22, 23, 24, 25) is removed by the cleaning unit (41, 42, 43, 44, 45).
The fixed transfer paper is conveyed to the second paper feed unit (17) for the second image formation. In the second image formation, each image signal of the normal glossy portion that is not subjected to the first image formation by the image calculation process is transmitted to the writing unit (15). Here, images of Y, M, C, and Bk other than transparent are written on the respective photosensitive drums (21, 22, 23, and 24), developed, transferred, and fixed again at the fixing unit as in the first image formation. .
It should be noted that the image formation for transparent toner can be applied to the portion of the photographic paper where the density is low depending on the image calculation process, or by specifying the area, the entire printing paper or the image portion is determined. It is possible to attach the transparent toner only to the portion that has been made.
In the apparatus of FIG. 4 and the image forming method using the same, the toner image formed on the photosensitive drum (21, 22, 23, 24, 25) is transferred once onto the transfer drum as in FIG. The toner image is transferred onto the transfer paper by the next transfer means (66) and fixed by the fixing device (80).
Both the image forming method 1 and the image forming method 2 can be used. When the transparent toner is placed thickly, the transparent toner layer on the transfer drum becomes thick and it is difficult to perform the secondary transfer. Therefore, a transfer drum can be used.

(Effect of crystalline polyester resin)
Since the crystalline polyester resin in the toner of the present invention has crystallinity, it exhibits a heat-melting characteristic that shows a sudden decrease in viscosity near the fixing start temperature. In other words, the heat-resistant storage stability due to crystallinity is good until just before the melting start temperature, and at the melting start temperature, a sharp viscosity drop (sharp melt property) occurs and the fixing is performed, so it has both good heat storage stability and low-temperature fixability. Toner can be designed. It was also found that good results were obtained with respect to the release width (difference between the fixing lower limit temperature and the hot offset occurrence temperature).

(Organic solvent)
As the organic solvent used in the crystalline polyester dispersion process, the crystalline polyester resin is completely dissolved at a high temperature to form a uniform solution. On the other hand, when cooled to a low temperature, the crystalline polyester resin phase-separates and becomes an opaque non-uniformity. Those that form a solution are used. Specifically, it is only necessary that the non-solvent characteristic is exhibited at a temperature lower than (Tm-40) ° C. and the good solvent characteristic is exhibited at a temperature higher than that based on the melting temperature (Tm) of the crystalline polyester resin. As specific examples, toluene, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone and the like can be used alone or in combination of two or more.

(Heat dissolution / cooling of crystalline polyester resin)
The crystalline polyester resin is melted by raising the temperature in the organic solvent and recrystallized by cooling. At that time, the crystalline polyester resin is heated and dissolved and cooled alone. If an amorphous polyester resin is mixed in this step, the crystalline polyester and the amorphous polyester are compatible with each other when heated and dissolved, and the sharp melt property of the crystalline polyester cannot be utilized in the toner. For this reason, the heating / dissolution / cooling step needs to be carried out solely in a crystalline polyester in an organic solvent.

The dispersed particle size of the crystalline polyester resin precipitated in the cooling process is determined by the concentration of the solution and the cooling rate. Further, after cooling, the non-crystalline polyester resin is dissolved in the dispersion, and finely divided by a mechanical pulverizer to produce a crystalline polyester dispersion. When the crystalline polyester resin alone is dispersed in the organic solvent, the solution viscosity becomes higher as the dispersed particle size becomes smaller, and it becomes difficult to control to the ideal 0.1 to 2.0 μm. Although there is a measure to lower the concentration of the solution in order to lower the solution viscosity, it is not realistic. Therefore, after cooling, it is preferable to perform mechanical pulverization by dissolving the amorphous polyester in the dispersion and controlling the solution viscosity. Moreover, the slurry temperature in mechanical grinding | pulverization needs to be less than (T2-cs1), when it is set as the endothermic shoulder temperature (T2-cs1) calculated from DSC temperature rising 2nd time of crystalline polyester. When the slurry temperature is set to (T2-cs1) or higher, the crystalline polyester is partially dissolved and compatible with the amorphous polyester, resulting in a decrease in the toner Tg and a deterioration in heat resistant storage stability.
If the dispersed particle diameter exceeds 2.0 μm, it is difficult to granulate the toner, and the particle size distribution tends to be broad. Therefore, the dispersed diameter needs to be 2.0 μm.

  The solution concentration is preferably 1 to 20% by weight of a crystalline polyester resin in an organic solvent at high temperature dissolution / cooling, and the ratio of crystalline polyester resin / amorphous polyester resin at mechanical grinding is 10 / It is desirable to mix the amorphous polyester so as to be 90 to 90/10.

(Mechanical grinding device)
Examples of the mechanical pulverization apparatus used in the step of micronizing the crystalline polyester resin precipitated in the cooling process include commercially available pulverization apparatuses such as a bead mill apparatus, a ball mill apparatus, a wet pulverization apparatus (Altima manufactured by Sugino Machine). An example of such a device is an Iser device).

(Crystalline polyester resin)
As an example, the crystalline polyester resin contains 80 mol% or more, preferably 85 to 100 mol% of a diol compound having 2 to 6 carbon atoms, particularly 1,4-butanediol, 1,6-hexanediol and derivatives thereof as an alcohol component. It is possible to synthesize by using a mol% content and an aliphatic dicarboxylic acid such as sebacic acid or adipic acid or a carboxylic acid having a double bond (C = C bond) such as fumaric acid as at least an acidic component.

In addition, as a method for controlling the crystallinity and softening point of the crystalline polyester resin, a trivalent or higher polyhydric alcohol such as glycerin as an alcohol component and a trivalent or higher polyvalent such as trimellitic anhydride as an acid component can be used during polyester synthesis. Examples thereof include a method of designing and using a non-linear polyester that has been subjected to condensation polymerization by adding a polyvalent carboxylic acid.
The molecular structure of the crystalline polyester resin of the present invention can be confirmed by X-ray diffraction, GC / MS, LC / MS, IR measurement, etc. in addition to NMR measurement by solution or solid. In this case, a material having absorption at 965 ± 10 cm ⁻¹ or 990 ± 10 cm ⁻¹ based on δCH (out-of-plane variable angular vibration) of olefin can be given as an example.

As for the molecular weight, from the viewpoint that the above-mentioned molecular weight distribution is sharp and the low molecular weight is excellent in low-temperature fixability, as a result of intensive studies, the molecular weight distribution by GPC of the soluble part of o-dichlorobenzene is indicated by the log ( M), the peak position of the molecular weight distribution chart in which the vertical axis is expressed in weight% is in the range of 3.5 to 4.0, the half width of the peak is 1.5 or less, and the weight average molecular weight (Mw) is 1000. It is preferable that -30000, number average molecular weight (Mn) is 500-6000, and Mw / Mn is 2-10.
The melting temperature and F1 / 2 temperature are desirably low as long as the heat resistant storage stability is not deteriorated, and the DSC endothermic peak temperature is preferably 50 to 130 ° C. When the DSC endothermic peak temperature is less than 50 ° C., the heat resistant storage stability is deteriorated, and blocking tends to occur at the temperature inside the developing device. It becomes impossible.

  The acid value of the crystalline polyester resin is 5 mgKOH / g or more, more preferably 10 mgKOH / g or more in order to achieve the desired low-temperature fixability from the viewpoint of the affinity between paper and resin. On the other hand, in order to improve the hot offset property, it is preferably 45 mgKOH / g or less. Further, the hydroxyl value of the crystalline polymer is preferably 0 to 50 mgKOH / g, more preferably 5 to 50 mgKOH / g in order to achieve a predetermined low-temperature fixability and to achieve good charging characteristics. .

  The binder resin component preferably contains a binder resin precursor.

(Binder resin precursor)
As the binder resin precursor, a binder resin precursor made of a modified polyester resin is preferable, and examples thereof include a polyester prepolymer modified with isocyanate or epoxy. This undergoes an extension reaction with a compound having an active hydrogen group (such as amines), and has an effect on improving the release width (difference between the minimum fixing temperature and the hot offset generation temperature) and heat-resistant storage stability.
As a method for synthesizing this polyester prepolymer, it can be easily synthesized by reacting a base polyester resin with a conventionally known isocyanate agent or epoxidizing agent. Isocyanating agents include aliphatic polyisocyanates (tetramethylene diisocyanate, hexamethylene diisocyanate, 2,6-diisocyanatomethylcaproate, etc.); alicyclic polyisocyanates (isophorone diisocyanate, cyclohexylmethane diisocyanate, etc.); aromatic diisocyanates (Tolylene diisocyanate, diphenylmethane diisocyanate, etc.); araliphatic diisocyanates (α, α, α ′, α′-tetramethylxylylene diisocyanate, etc.); isocyanurates; block the polyisocyanates with phenol derivatives, oximes, caprolactam, etc. And combinations of two or more of these. Moreover, as an epoxidizing agent, epichlorohydrin etc. can be mentioned as the representative example.

The ratio of the isocyanate agent is usually 5/1 to 1/1, preferably 4/1 to 1 as an equivalent ratio [NCO] / [OH] of the isocyanate group [NCO] and the hydroxyl group [OH] of the base polyester. 1.2 / 1, more preferably 2.5 / 1 to 1.5 / 1. When [NCO] / [OH] exceeds 5, low-temperature fixability deteriorates. When the molar ratio of [NCO] is less than 1, the urea content of this polyester prepolymer becomes low, and the hot offset resistance deteriorates.
The content of the isocyanate agent in the polyester prepolymer is usually 0.5 to 40% by weight, preferably 1 to 30% by weight, and more preferably 2 to 20% by weight. If it is less than 0.5% by weight, the hot offset resistance deteriorates, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. On the other hand, if it exceeds 40% by weight, the low-temperature fixability deteriorates.

The number of isocyanate groups contained per molecule in the polyester prepolymer is usually 1 or more, preferably 1.5 to 3 on average, and more preferably 1.8 to 2.5 on average. If it is less than 1 per molecule, the molecular weight of the urea-modified polyester resin after the elongation reaction is lowered, and the hot offset resistance is deteriorated.
The binder resin precursor preferably has a weight average molecular weight of 1 × 10 ⁴ or more and 3 × 10 ⁵ or less.

(Compound that stretches or crosslinks with binder resin precursor)
Examples of the compound that extends or crosslinks with the binder resin precursor include compounds having an active hydrogen group, and typical examples thereof include amines. Examples of amines include diamine compounds, trivalent or higher polyamine compounds, amino alcohol compounds, amino mercaptan compounds, amino acid compounds, and compounds in which these amino groups are blocked. Examples of diamine compounds include aromatic diamines (phenylenediamine, diethyltoluenediamine, 4,4′diaminodiphenylmethane, etc.); alicyclic diamines (4,4′-diamino-3,3′dimethyldicyclohexylmethane, diaminecyclohexane, isophoronediamine). Etc.); and aliphatic diamines (ethylenediamine, tetramethylenediamine, hexamethylenediamine, etc.) and the like. Examples of the trivalent or higher polyamine compound include diethylenetriamine and triethylenetetramine. Examples of amino alcohol compounds include ethanolamine and hydroxyethylaniline. Examples of the amino mercaptan compound include aminoethyl mercaptan and aminopropyl mercaptan.

Examples of amino acid compounds include aminopropionic acid and aminocaproic acid.
Examples of the compounds in which these amino groups are blocked include ketimine compounds and oxazoline compounds obtained from the amines and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.). Among these amines, preferred are a diamine compound and a mixture of a diamine compound and a small amount of a polyamine compound.

(Release agent)
The release agent is preferably a wax having a melting point of 50 to 120 ° C.
Since such a wax can effectively act as a release agent between the fixing roller and the toner interface, high temperature offset resistance can be improved without applying a release agent such as oil to the fixing roller. be able to.
In addition, melting | fusing point of wax is calculated | required by measuring the maximum endothermic peak using TG-DSC system TAS-100 (made by Rigaku Corporation) which is a differential scanning calorimeter.

As the mold release agent, the following materials can be used.
As waxes and waxes, plant waxes such as carnauba wax, cotton wax, wood wax, and rice wax; animal waxes such as beeswax and lanolin; mineral waxes such as ozokerite and cercin; paraffin, microcrystalline, petrolatum, etc. And petroleum wax.
In addition, examples of mold release agents other than these natural waxes include synthetic hydrocarbon waxes such as Fischer-Tropsch wax and polyethylene wax; and synthetic waxes such as esters, ketones, and ethers.
Furthermore, fatty acid amides such as 1,2-hydroxystearic acid amide, stearic acid amide, phthalic anhydride imide, chlorinated hydrocarbons; low molecular weight crystalline polymer, poly (n-stearyl methacrylate), poly (methacrylic acid n) -A crystalline polymer having a long-chain alkyl group in the side chain, such as a homopolymer or copolymer of polyacrylate such as lauryl (for example, n-stearyl acrylate-ethyl methacrylate copolymer) is also used as a release agent. Can do.

(Charge control agent)
The toner of the present invention may contain a charge control agent as necessary. As the charge control agent, known ones can be used, but those that are highly colored are not preferred as transparent toners.
For example, alkoxy amines, quaternary ammonium salts (including fluorine-modified quaternary ammonium salts), alkylamides alone or compounds, fluorine activators, and the like.

  The amount of the charge control agent used is determined by the toner production method including the type of binder resin, the presence or absence of additives used as necessary, and the dispersion method, but is not uniquely limited. Preferably, it is used in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin. The range of 0.2 to 5 parts by weight is preferable. When the amount exceeds 10 parts by weight, the chargeability of the toner is too high, the effect of the main charge control agent is reduced, the electrostatic attractive force with the developing roller is increased, the flowability of the developer is reduced, and the image density is reduced. Incurs a decline. These charge control agents can be dissolved and dispersed after being melt-kneaded with a masterbatch and resin, or of course, may be added when directly dissolving or dispersing in an organic solvent, or may be fixed on the toner surface after preparation of toner particles. May be.

(Unmodified polyester resin)
In the present invention, an amorphous unmodified polyester resin can be used as the binder resin component. It is preferable that at least a part of the modified polyester resin obtained by crosslinking and / or elongation reaction of the binder resin precursor made of the modified polyester resin is compatible with the unmodified polyester resin. Thereby, low temperature fixability and hot offset resistance can be improved. For this reason, it is preferable that the polyol and polycarboxylic acid of the modified polyester resin and the unmodified polyester resin have similar compositions. Further, as the unmodified polyester resin, the non-modified polyester resin used in the crystalline polyester dispersion can also be used as long as it is unmodified.

  The acid value of the unmodified polyester resin is usually 1 to 50 KOHmg / g, preferably 5 to 30 KOHmg / g. Thereby, since the acid value is 1 KOHmg / g or more, the toner is likely to be negatively charged, and further, the affinity between the paper and the toner is improved at the time of fixing to the paper, and the low-temperature fixability can be improved. . However, if the acid value exceeds 50 KOHmg / g, the charging stability, particularly the charging stability against environmental fluctuations, may be reduced. In the present invention, the unmodified polyester resin preferably has an acid value of 1 to 50 KOHmg / g.

The hydroxyl value of the unmodified polyester resin is preferably 5 KOHmg / g or more.
The hydroxyl value is measured using a method based on JIS K0070-1966.
Specifically, first, 0.5 g of a sample is precisely weighed into a 100 ml volumetric flask, and 5 ml of an acetylating reagent is added thereto. Next, after heating in a 100 ± 5 ° C. warm bath for 1-2 hours, the flask is removed from the warm bath and allowed to cool. Furthermore, acetic anhydride is decomposed by adding water and shaking.
Next, in order to completely decompose acetic anhydride, the flask is again heated in a warm bath for 10 minutes or more and allowed to cool, and then the wall of the flask is thoroughly washed with an organic solvent.
Furthermore, the hydroxyl value was measured at 23 ° C. using an automatic potentiometric titrator DL-53 Titrator (manufactured by METTLER TOLEDO) and electrode DG113-SC (manufactured by METTLER TOLEDO), and analysis software LabX Light Version 1.00 Analyze using .000. For calibration of the apparatus, a mixed solvent of 120 ml of toluene and 30 ml of ethanol is used.

At this time, the measurement conditions are as follows.
Still
Speed [%] 25
Time [s] 15
EQP titration
Titrant / Sensor
Titrant CH ₃ ONa
Concentration [mol / L] 0.1
Sensor DG115
Unit of measurement mV
Predispensing to volume
Volume [mL] 1.0
Wait time [s] 0
Titrant addition Dynamic
dE (set) [mV] 8.0
dV (min) [mL] 0.03
dV (max) [mL] 0.5
Measurement mode Equilibrium controlled
dE [mV] 0.5
dt [s] 1.0
t (min) [s] 2.0
t (max) [s] 20.0
Recognition
Threshold 100.0
Steppes jump only No
Range No
Tendency None
Termination
at maximum volume [mL] 10.0
at potential No
at slope No
after number EQPs Yes
n = 1
comb. termination conditions No
Evaluation
Procedure Standard
Potential1 No
Potentialial No
Stop for revaluation No

  The urea-modified polyester resin can be used in combination with a polyester resin modified with a chemical bond other than a urea bond, for example, a polyester resin modified with a urethane bond, in addition to an unmodified polyester resin.

When the toner composition contains a modified polyester resin such as a urea-modified polyester resin, the modified polyester resin can be produced by a one-shot method or the like.
As an example, a method for producing a urea-modified polyester resin will be described.
First, a polyol and a polycarboxylic acid are heated to 150 to 280 ° C. in the presence of a catalyst such as tetrabutoxy titanate or dibutyltin oxide, and if necessary, water generated while removing pressure is removed to have a hydroxyl group. A polyester resin is obtained. Next, a polyester resin having a hydroxyl group is reacted with polyisocyanate at 40 to 140 ° C. to obtain a polyester prepolymer having an isocyanate group. Furthermore, the polyester prepolymer having an isocyanate group is reacted with amines at 0 to 140 ° C. to obtain a urea-modified polyester resin.
The number average molecular weight of the urea-modified polyester resin is usually 1000 to 10000, preferably 1500 to 6000.

In addition, when making the polyester resin which has a hydroxyl group and polyisocyanate react, and when making the polyester prepolymer which has an isocyanate group, and amines react, a solvent can also be used as needed.
Solvents include aromatic solvents (toluene, xylene, etc.); ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.); esters (ethyl acetate, etc.); amides (dimethylformamide, dimethylacetamide, etc.); ethers (tetrahydrofuran) And the like which are inert with respect to the isocyanate group.
In addition, when using unmodified polyester resin together, you may mix to the solution after reaction of the urea modified polyester resin what was manufactured similarly to the polyester resin which has a hydroxyl group.

  In the present invention, as the binder resin component contained in the oil phase, a crystalline polyester resin, an amorphous polyester resin, a binder resin precursor, and an unmodified polyester resin may be used in combination. Other binder resin components may be contained. The binder resin component preferably contains a polyester resin, and more preferably contains 50% by weight or more of the polyester resin. If the content of the polyester resin is less than 50% by weight, the low-temperature fixability may be lowered. It is particularly preferable that all of the binder resin components are polyester resins.

  Examples of binder resin components other than polyester resins include polystyrene, poly (p-chlorostyrene), styrene-substituted polymers such as polyvinyltoluene, styrene-substituted polymers, styrene-p-chlorostyrene copolymers, and styrene-propylene copolymers. Polymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-acrylic acid Octyl copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer , Styrene-vinyl methyl ketone copolymer Styrene copolymers such as styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer; Methyl acid, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, epoxy resin, epoxy polyol resin, polyurethane resin, polyamide resin, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, fat Aromatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax and the like.

(Toner production method in aqueous medium)
Examples of the toner production method in the present invention are given below.
The aqueous medium used in the present invention may be water alone, or a solvent miscible with water may be used in combination. Examples of miscible solvents include alcohols (methanol, isopropanol, ethylene glycol, etc.), dimethylformamide, tetrahydrofuran, cellosolves (eg, methyl cellosolv (registered trademark)), lower ketones (eg, acetone, methyl ethyl ketone), and the like.

  The binder resin precursor, release agent, crystalline polyester dispersion, charge control agent, unmodified polyester resin, silica, etc. that form toner particles may be mixed when forming the dispersion in an aqueous medium. However, it is more preferable to mix these toner raw materials in advance and then add and disperse the mixture in an aqueous medium. In the present invention, toner raw materials such as a release agent and a charge control agent are not necessarily mixed when forming particles in an aqueous medium, and may be added after the particles are formed. Good.

  The dispersion method is not particularly limited, and known equipment such as a low-speed shear method, a high-speed shear method, a friction method, a high-pressure jet method, and an ultrasonic wave can be applied. In order to make the particle size of the dispersion 2 to 20 μm, a high-speed shearing type is preferable. When a high-speed shearing disperser is used, the rotational speed is not particularly limited, but the peripheral speed is 5 to 50 m / s. The dispersion time is not particularly limited, but in the case of a batch method, it is usually 0.1 to 60 minutes. The temperature during dispersion is usually 0 to 80 ° C. (under pressure), preferably 10 to 40 ° C.

  The amount of the aqueous medium used is usually 100 to 1000 parts by weight with respect to 100 parts by weight of the toner composition. If the amount is less than 100 parts by weight, the dispersion state of the toner composition is poor, and toner particles having a predetermined particle diameter cannot be obtained. If it exceeds 1000 parts by weight, it is not economical. Moreover, a dispersing agent can also be used as needed. It is preferable to use a dispersant because the particle size distribution becomes sharp and the dispersion is stable.

  As a method of reacting the polyester prepolymer and the compound having active hydrogen groups, the compound having active hydrogen groups may be added and reacted before dispersing the toner composition in the aqueous medium, or dispersed in the aqueous medium. Then, a compound having an active hydrogen group may be added to cause a reaction from the particle interface. In this case, a polyester modified with a polyester prepolymer is preferentially produced on the surface of the toner to be produced, and a concentration gradient can be provided inside the particles.

  Anionic interfaces such as alkylbenzene sulfonates, α-olefin sulfonates and phosphates as dispersants for emulsifying and dispersing the oil phase in which the toner composition is dispersed in a liquid (aqueous medium) containing water. Activators, alkylamine salts, amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, amine salt types such as imidazoline, alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkyldimethylbenzylammonium salts, pyridinium salts, alkylisoquinolinium salts , Quaternary ammonium salt type cationic surfactants such as benzethonium chloride, nonionic surfactants such as fatty acid amide derivatives and polyhydric alcohol derivatives, such as alanine, dodecyldi (aminoethyl) glycine, di (octylaminoethyl) glycine And - alkyl -N, amphoteric surfactants such as N- dimethyl ammonium betaine and the like.

  Further, by using a surfactant having a fluoroalkyl group, the effect can be obtained in a very small amount. Preferred anionic surfactants having a fluoroalkyl group include fluoroalkyl carboxylic acids having 2 to 10 carbon atoms and metal salts thereof, disodium perfluorooctanesulfonyl glutamate, 3- [omega-fluoroalkyl (C6-C11 ) Oxy] -1-alkyl (C3-C4) sodium sulfonate, 3- [omega-fluoroalkanoyl (C6-C8) -N-ethylamino] -1-propanesulfonic acid sodium, fluoroalkyl (C11-C20) carvone Acids and metal salts thereof, perfluoroalkylcarboxylic acids (C7 to C13) and metal salts thereof, perfluoroalkyl (C4 to C12) sulfonic acids and metal salts thereof, perfluorooctanesulfonic acid diethanolamide, N-propyl-N- (2-hydroxyethyl ) Perfluorooctanesulfonamide, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (C6-C10) -N-ethylsulfonylglycine salt, monoperfluoroalkyl (C6-C16) ethyl phosphate Etc.

  Product names include Surflon S-111, S-112, S-113 (Asahi Glass Co., Ltd.), Florard FC-93, FC-95, FC-98, FC-129 (Sumitomo 3M Co., Ltd.), Unidyne DS-101. DS-102 (Daikin Kogyo Co., Ltd.), MegaFuck F-110, F-120, F-113, F-191, F-812, F-833 (Dainippon Ink Co., Ltd.), Xtop EF-102 , 103, 104, 105, 112, 123A, 123B, 306A, 501, 201, 204 (manufactured by Tochem Products), and Fgentent F-100, F150 (manufactured by Neos).

  Examples of cationic surfactants include aliphatic primary, secondary or tertiary amine acids having a fluoroalkyl group, aliphatic quaternary ammonium salts such as perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salts, and benzaza. Luconium salt, benzethonium chloride, pyridinium salt, imidazolinium salt, trade names include Surflon S-121 (Asahi Glass), Florard FC-135 (Sumitomo 3M), Unidyne DS-202 (Daikin Industries) Megafac F-150, F-824 (manufactured by Dainippon Ink, Inc.), Xtop EF-132 (manufactured by Tochem Products), and Footgent F-300 (manufactured by Neos).

Further, tricalcium phosphate, calcium carbonate, titanium oxide, colloidal silica, hydroxyapatite and the like can be used as an inorganic compound dispersant which is hardly soluble in water.
Further, the dispersed droplets may be stabilized by a polymer protective colloid or water-insoluble organic fine particles. For example, acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid or maleic anhydride and other (meth) acrylic monomers containing hydroxyl groups Bodies such as β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, β-hydroxypropyl acrylate, β-hydroxypropyl methacrylate, γ-hydroxypropyl acrylate, γ-hydroxypropyl methacrylate, 3-acrylate Chloro-2-hydroxypropyl, 3-chloro-2-hydroxypropyl methacrylate, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerol monoacrylate, glycerol monomethacrylate, N- Methylol acrylamide, N-methylol methacrylamide, etc., vinyl alcohol or ethers with vinyl alcohol, such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, or esters of compounds containing vinyl alcohol and a carboxyl group, For example, vinyl acetate, vinyl propionate, vinyl butyrate, acrylamide, methacrylamide, diacetone acrylamide or their methylol compounds, acid chlorides such as acrylic acid chloride, methacrylic acid chloride, vinyl pyridine, vinyl pyrrolidone, vinyl imidazole, ethyleneimine Homopolymers or copolymers such as those having a nitrogen atom or its heterocyclic ring, polyoxyethylene, polyoxypropylene, poly Xylethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonyl phenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, polyoxyethylene nonylphenyl Polyoxyethylenes such as esters, celluloses such as methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose can be used.

In addition, when an acid such as calcium phosphate salt or an alkali-soluble substance is used as the dispersion stabilizer, the calcium phosphate salt is removed from the fine particles by a method such as dissolving the calcium phosphate salt with an acid such as hydrochloric acid and washing with water. To do. It can also be removed by operations such as enzymatic degradation.
When a dispersant is used, the dispersant can remain on the surface of the toner particles. However, it is preferable from the charged surface of the toner to wash away after the reaction.

  Further, in order to lower the viscosity of the toner composition, a solvent in which the polyester prepolymer reacts and is modified with a modified polyester can be used. The use of a solvent is preferable in that the particle size distribution becomes sharp. The solvent is preferably volatile with a boiling point of less than 100 ° C. from the viewpoint of easy removal. Examples of the solvent include toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, ethyl acetate, Methyl ethyl ketone, methyl isobutyl ketone and the like can be used alone or in combination of two or more.

  In particular, aromatic solvents such as toluene and xylene and halogenated hydrocarbons such as methylene chloride, 1,2-dichloroethane, chloroform, and carbon tetrachloride are preferable. The usage-amount of the solvent with respect to 100 parts of polyester prepolymers is 0-300 parts normally, Preferably it is 0-100 parts, More preferably, it is 25-70 parts. When a solvent is used, it is removed by heating under normal pressure or reduced pressure after elongation and / or crosslinking reaction.

  The elongation and / or crosslinking reaction time is selected depending on the reactivity depending on the combination of the polyester prepolymer and the compound having an active hydrogen group, and is usually 10 minutes to 40 hours, preferably 30 minutes to 24 hours. The reaction temperature is usually 0 to 100 ° C., preferably 10 to 50 ° C. Moreover, a well-known catalyst can also be used as needed. Specific examples include tertiary amines such as triethylamine and imidazoles.

  In order to remove the organic solvent from the obtained emulsified dispersion, a method in which the temperature of the entire system is gradually raised to completely evaporate and remove the organic solvent in the droplets can be employed. Alternatively, the emulsified dispersion can be sprayed into a dry atmosphere to completely remove the water-insoluble organic solvent in the droplets to form toner fine particles, and the aqueous dispersant can be removed by evaporation together. . As a dry atmosphere in which the emulsified dispersion is sprayed, a gas obtained by heating air, nitrogen, carbon dioxide gas, combustion gas, or the like, in particular, various air currents heated to a temperature equal to or higher than the boiling point of the highest boiling solvent used is generally used. Sufficient quality can be obtained by short-time treatment such as spray dryer, belt dryer, rotary kiln.

When the particle size distribution at the time of emulsification dispersion is wide and washing and drying processes are performed while maintaining the particle size distribution, the particle size distribution can be adjusted by classification into a desired particle size distribution.
In the classification operation, the fine particle portion can be removed in the liquid by a cyclone, a decanter, centrifugation, or the like. Of course, the classification operation may be performed after obtaining the powder as a powder after drying. The unnecessary fine particles or coarse particles obtained can be returned to the kneading step and used for the formation of particles. At that time, fine particles or coarse particles may be wet.
The dispersant used is preferably removed from the obtained dispersion as much as possible, but it is preferable to carry out it simultaneously with the classification operation described above.

  The obtained dried toner powder is mixed with different kinds of particles such as release agent fine particles, charge control fine particles, fluidizing agent fine particles, and fixed on the surface by applying mechanical impact force to the mixed powder. , And detachment of foreign particles from the surface of the resulting composite particles can be prevented.

  Specific means include a method of applying an impact force to the mixture by blades rotating at high speed, a method of injecting and accelerating the mixture in a high-speed air stream, and causing particles or composite particles to collide with an appropriate collision plate, etc. is there. As equipment, Ong mill (manufactured by Hosokawa Micron Co., Ltd.), I-type mill (manufactured by Nippon Pneumatic Co., Ltd.) has been modified to reduce the pulverization air pressure, hybridization system (manufactured by Nara Machinery Co., Ltd.), kryptron System (manufactured by Kawasaki Heavy Industries, Ltd.), automatic mortar, etc.

(External additive)
The toner of the present invention may contain an external additive in order to assist fluidity, developability and chargeability.
As the external additive, inorganic fine particles can be preferably used. The primary particle diameter of the inorganic fine particles is preferably 5 nm to 2 μm, and particularly preferably 5 nm to 500 mμ. Moreover, it is preferable that the specific surface area by BET method is 20-500 m < ² > / g.
The proportion of the inorganic fine particles used is preferably 0.01 to 5% by weight of the toner, and particularly preferably 0.01 to 2.0% by weight. Specific examples of the inorganic fine particles include, for example, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, silica sand, clay, mica, wollastonite, diatomaceous earth. Examples include soil, chromium oxide, cerium oxide, pengala, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride.

  Other polymer fine particles such as polystyrene, methacrylic acid ester and acrylic acid ester copolymer obtained by soap-free emulsion polymerization, suspension polymerization, and dispersion polymerization, polycondensation systems such as silicone, benzoguanamine, and nylon, and thermosetting resins Examples include polymer particles.

  Such a fluidizing agent performs surface treatment to increase hydrophobicity, and can prevent deterioration of flow characteristics and charging characteristics even under high humidity. For example, silane coupling agents, silylating agents, silane coupling agents having an alkyl fluoride group, organic titanate coupling agents, aluminum coupling agents, silicone oils, modified silicone oils and the like are preferable surface treatment agents. .

  Examples of the cleaning property improver for removing the developer after transfer remaining on the photoreceptor or the primary transfer medium include, for example, zinc stearate, calcium stearate, fatty acid metal salts such as stearic acid, such as polymethyl methacrylate fine particles, polystyrene fine particles, etc. And polymer fine particles produced by soap-free emulsion polymerization. The polymer fine particles preferably have a relatively narrow particle size distribution and a volume average particle size of 0.01 to 1 μm.

In the present invention, the acid value is measured using a method based on JIS K0070-1992.
Specifically, first, 0.5 g of a sample (0.3 g in the case where ethyl acetate is soluble) is added to 120 ml of toluene and dissolved by stirring at 23 ° C. for about 10 hours. Next, 30 ml of ethanol is added to prepare a sample solution. When the sample does not dissolve, a solvent such as dioxane or tetrahydrofuran is used. Furthermore, an acid value was measured at 23 ° C. using an automatic potentiometric titrator DL-53 Titator (manufactured by METTLER TOLEDO) and electrode DG113-SC (manufactured by METTLER TOLEDO), and analysis software LabX Light Version 1.00 Analyze using .000.
For calibration of the apparatus, a mixed solvent of 120 ml of toluene and 30 ml of ethanol is used.
At this time, the measurement conditions are the same as in the case of the hydroxyl value.
The acid value can be measured as described above. Specifically, the acid value is titrated with a 0.1N potassium hydroxide / alcohol solution standardized in advance, and from the titration, the formula acid value [KOHmg / g] = Titrate [ml] x N x 56.1 [mg / ml] / sample weight [g] (where N is a factor of 0.1 N potassium hydroxide / alcohol solution).

  In the present invention, the polyester resin preferably has a glass transition point of 40 to 70 ° C. When the glass transition point is less than 40 ° C., the heat-resistant storage stability may be lowered, and when it exceeds 70 ° C., the low-temperature fixability may be lowered.

In the present invention, the endothermic peak temperature and endothermic shoulder temperature of crystalline polyester, amorphous polyester, and toner are measured using, for example, a DSC system (differential scanning calorimeter) (“DSC-60”, manufactured by Shimadzu Corporation). Can be measured.
Specifically, the endothermic shoulder 1, endothermic peak, and endothermic shoulder 2 of the target sample can be measured by the following procedure. First, about 5.0 mg of polyester resin is put in an aluminum sample container, the sample container is placed on a holder unit, and set in an electric furnace. Next, heating is performed from 0 ° C. to 150 ° C. at a heating rate of 10 ° C./min in a nitrogen atmosphere. Thereafter, the sample is cooled from 150 ° C. to 0 ° C. at a rate of temperature decrease of 10 ° C./min, and further heated to 150 ° C. at a rate of temperature increase of 10 ° C./min. The DSC curve is measured using From the obtained DSC curve, use the analysis program in the DSC-60 system to select the DSC curve at the first temperature rise, and use the “endothermic shoulder temperature” in the analysis program to raise the temperature of the target sample. Select endothermic shoulder 1 and endothermic shoulder 2 at the first time, DSC curve at the second temperature increase, and use “endothermic shoulder temperature” to determine the endothermic shoulder 1 and endothermic shoulder 2 at the second temperature increase of the target sample. Can be sought. The shoulder temperature is defined as an endothermic shoulder 1, an endothermic shoulder 2,. Further, from the obtained DSC curve, using the analysis program in the DSC-60 system, using the “endothermic peak temperature” in the analysis program, the DSC curve at the first temperature rise is selected, and the target sample By selecting the endothermic peak at the first temperature increase and the DSC curve at the second temperature increase and using the “endothermic peak temperature” in the analysis program, the endothermic peak at the second temperature increase of the target sample can be obtained. .
FIG. 5 shows an example of DSC measurement of crystalline polyester.

(1 component developer, 2 component developer)
When the toner of the present invention is used for a two-component developer, it may be used by mixing with a magnetic carrier. The carrier to toner content ratio in the developer is 1 to 10 weights of toner with respect to 100 parts by weight of carrier. Part is preferred. As the magnetic carrier, conventionally known ones such as iron powder, ferrite powder, magnetite powder, magnetic resin carrier having a particle diameter of about 20 to 200 μm can be used.
Examples of the coating material include amino resins such as urea-formaldehyde resin, melamine resin, benzoguanamine resin, urea resin, and polyamide resin.

  Polyvinyl and polyvinylidene resins such as acrylic resins, polymethyl methacrylate resins, polyacrylonitrile resins, polyvinyl acetate resins, polyvinyl alcohol resins, polyvinyl butyral resins, polystyrene resins and styrene acrylic copolymer resins, Halogenated olefin resins such as vinyl, polyester resins such as polyethylene terephthalate resin and polybutylene terephthalate resin, polycarbonate resins, polyethylene resins, polyvinyl fluoride resins, polyvinylidene fluoride resins, polytrifluoroethylene resins, polyhexafluoro Propylene resin, copolymer of vinylidene fluoride and acrylic monomer, copolymer of vinylidene fluoride and vinyl fluoride, tetrafluoroethylene and vinylidene fluoride Fluoro such as terpolymers of non-fluoride monomers including, and silicone resins, epoxy resins, and the like and.

In the present invention, the particle size distribution is measured using a Coulter counter method.
Examples of the particle size distribution measuring apparatus include Coulter Counter TA-II and Coulter Multisizer II (both manufactured by Coulter).
In the present invention, a PC-9801 personal computer (manufactured by NEC Corporation) is connected to the Coulter Counter TA-II type measuring apparatus via an interface (manufactured by Nikka Giken) that outputs the number distribution and volume distribution. The particle size distribution is measured.
Specifically, first, 0.1 to 5 ml of a surfactant (preferably alkyl benzene sulfonate) is added as a dispersant to 100 to 150 ml of the electrolytic solution. The electrolytic solution is prepared by preparing an aqueous solution of about 1% by weight using primary sodium chloride, and for example, ISOTON-II (manufactured by Coulter) can be used. Next, 2 to 20 mg of the sample is added and suspended, and then dispersed with an ultrasonic disperser for 1 to 3 minutes. Using the 100 μm aperture, the volume and number of toners are measured from the obtained dispersion, and the volume distribution and number distribution are calculated.
The channel is 2.00 μm or more and less than 2.52 μm, 2.52 μm or more and less than 3.17 μm, 3.17 μm or more and less than 4.00 μm, 4.00 μm or more and less than 5.04 μm, 5.04 μm or more and less than 6.35 μm, 6.35 μm or more and less than 8.00 μm, 8.00 μm or more and less than 10.08 μm, 10.08 μm or more and less than 12.70 μm, 12.70 μm or more and less than 16.00 μm, 16.00 μm or more and less than 20.20 μm, 20.20 μm or more and 25 or more The target is particles having a particle size of 2.00 μm or more and less than 40.30 μm using 13 channels of less than 40 μm, 25.40 μm or more and less than 32.00 μm and 32.00 μm or more and less than 40.30 μm.

  The volume average particle size of the toner of the present invention is preferably 3 μm or more and 7 μm or less, and the ratio of the volume average particle size to the number average particle size is preferably 1.2 or less. Moreover, it is preferable that the component whose particle size is 2 micrometers or less is 10 number% or less.

The acid value of the toner of the present invention is an important index for low-temperature fixability and high-temperature offset resistance, and is derived from the terminal carboxyl group of the unmodified polyester resin. In order to control the offset generation temperature and the like, it is preferably 0.5 to 40 KOH mg / g.
When the acid value exceeds 40 KOH mg / g, the extension reaction and / or the cross-linking reaction of the reactive modified polyester resin become insufficient, and the high temperature offset resistance may be lowered. On the other hand, if the acid value is less than 0.5 KOHmg / g, the effect of improving the dispersion stability by the base at the time of production cannot be obtained, or the elongation reaction and / or the crosslinking reaction of the reactive modified polyester resin can easily proceed. As a result, the production stability may be reduced.

The toner of the present invention preferably has a glass transition point of 40 to 70 ° C. Thereby, low temperature fixability, heat resistant storage stability and high durability can be obtained.
If the glass transition point is less than 40 ° C., blocking in the developing machine or filming to the photoreceptor may occur, and if it exceeds 70 ° C., the low-temperature fixability may be deteriorated.

  The developer of the present invention is preferably a two-component developer having the toner of the present invention but further having a carrier. At this time, the toner content is preferably 1 to 10% by weight based on the carrier.

As the carrier, iron powder, ferrite powder, magnetite powder or the like having a particle size of about 20 to 200 μm can be used.
Carriers include amino resins such as urea-formaldehyde resin, melamine resin, benzoguanamine resin, urea resin, polyamide resin; epoxy resin; acrylic resin, polymethyl methacrylate, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, etc. Polyvinyl resin; Polyvinylidene resin; Polystyrene resin such as polystyrene and styrene acrylic copolymer resin; Halogenated olefin resin such as polyvinyl chloride; Polyester resin such as polyethylene terephthalate and polybutylene terephthalate; Polycarbonate resin, polyethylene, Polyvinyl fluoride, polyvinylidene fluoride, polytrifluoroethylene, polyhexafluoropropylene, copolymer of vinylidene fluoride and acrylic monomer, fluoride Vinylidene and copolymers of vinyl fluoride, fluoro terpolymers such as terpolymers of tetrafluoroethylene, vinylidene fluoride and non-fluorinated monomer, may be coated with a coating resin such as silicone resin.
Moreover, the coating resin may contain conductive powder such as metal powder, carbon black, titanium oxide, tin oxide, and zinc oxide, if necessary.
The conductive powder preferably has an average particle size of 1 μm or less. When the average particle diameter exceeds 1 μm, it may be difficult to control the electric resistance.

  Further, the developer of the present invention may be a one-component developer having no carrier, that is, a magnetic toner or a non-magnetic toner.

EXAMPLES The present invention will be further described below with reference to examples, but the present invention is not limited thereto.
Hereinafter, a part shows a weight part.

[Production Example of Crystalline Polyester Resin 1]
In a 5-liter four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple, 110 parts by weight of an aliphatic diol listed in Table 1, 170 parts by weight of a dicarboxylic acid listed in Table 1, and hydroquinone 1 part was charged and reacted at 250 ° C. for 5 hours, then heated to 200 ° C. and reacted for 1 hour.
Subsequently, the crystalline polyester 1 was synthesize | combined by making it react under the pressurization of 8.3 kPa for 1 hour.

[Production Example of Crystalline Polyester Resin 2]
Crystalline polyester 2 was prepared by changing the type and amount of dicarboxylic acid shown in Table 1 and the type and amount of aliphatic diol. The characteristics of the obtained crystalline polyester 2 are shown in Table 1.

[Production Example of Crystalline Polyester Resin 3]
Crystalline polyester 3 was prepared by changing the type and amount of dicarboxylic acid shown in Table 1 and the type and amount of aliphatic diol. The characteristics of the obtained crystalline polyester 3 are shown in Table 1.

[Production Example of Crystalline Polyester Resin 4]
Crystalline polyester 4 was prepared by changing the type and amount of dicarboxylic acid shown in Table 1 and the type and amount of aliphatic diol. The characteristics of the obtained crystalline polyester 4 are shown in Table 1.

[Production Example of Crystalline Polyester Resin 5]
Crystalline polyester 5 was prepared by changing the type and amount of dicarboxylic acid shown in Table 1 and the type and amount of aliphatic diol. The characteristics of the obtained crystalline polyester 5 are shown in Table 1.

[Production Example of Crystalline Polyester Resin 6]
Crystalline polyester 6 was prepared by changing the type and amount of dicarboxylic acid shown in Table 1 and the type and amount of aliphatic diol. The characteristics of the obtained crystalline polyester 6 are shown in Table 1.

[Example 1]
[Synthesis of Amorphous Polyester (Low Molecular Polyester) Resin 1]
240 parts of bisphenol A ethylene oxide 2-mole adduct, 527 parts of bisphenol A propylene oxide 3-mole adduct, 210 parts of terephthalic acid, 46 parts of adipic acid and 2 parts of dibutyltin oxide were reacted at 230 ° C for 8 hours at normal pressure. Further, after reacting for 6 hours at a reduced pressure of 10 to 15 mmHg, 44 parts of trimellitic anhydride was placed in the reaction vessel and reacted for 2 hours at 180 ° C. and normal pressure to obtain [Amorphous Polyester 1]. [Amorphous polyester 1] had a number average molecular weight of 2300, a weight average molecular weight of 6000, a Tg of 47 ° C., and an acid value of 25.

[Synthesis of polyester prepolymer]
In a reaction vessel equipped with a cooling pipe, a stirrer and a nitrogen introduction pipe, 682 parts of bisphenol A ethylene oxide 2-mole adduct, 81 parts of bisphenol A propylene oxide 2-mole adduct, 283 parts of terephthalic acid, trimellitic anhydride 22 And 2 parts of dibutyltin oxide were added, reacted at 230 ° C. for 8 hours at normal pressure, and further reacted for 6 hours at a reduced pressure of 10 to 15 mmHg to obtain [Intermediate Polyester 1]. [Intermediate Polyester 1] had a number average molecular weight of 2100, a weight average molecular weight of 9000, Tg of 58 ° C., an acid value of 0.5, and a hydroxyl value of 51.
Next, 410 parts of [Intermediate Polyester 1], 89 parts of isophorone diisocyanate and 500 parts of ethyl acetate are placed in a reaction vessel equipped with a cooling pipe, a stirrer and a nitrogen introduction pipe, and reacted at 100 ° C. for 5 hours. Polymer 1] was obtained. [Prepolymer 1] had a free isocyanate weight% of 1.53%.

[Synthesis of ketimine]
In a reaction vessel equipped with a stir bar and a thermometer, 170 parts of isophoronediamine and 75 parts of methyl ethyl ketone were charged and reacted at 50 ° C. for 5 hours to obtain [ketimine compound 1].
The amine value of [ketimine compound 1] was 418.

[Synthesis of Organic Fine Particle Emulsion-Preparation of Toner 1]
In a reaction vessel equipped with a stir bar and a thermometer, 683 parts of water, 11 parts of sodium salt of ethylene oxide methacrylate adduct sulfate (Eleminol RS-30: manufactured by Sanyo Chemical Industries), 138 parts of styrene, 138 parts of methacrylic acid, When 1 part of ammonium persulfate was charged and stirred at 400 rpm for 15 minutes, a white emulsion was obtained. The system was heated to raise the system temperature to 75 ° C. and reacted for 5 hours. Further, 30 parts of a 1% ammonium persulfate aqueous solution was added, and the mixture was aged at 75 ° C. for 5 hours, and an aqueous dispersion of a vinyl resin (a copolymer of styrene-methacrylic acid-methacrylic acid ethylene oxide adduct sulfate sodium salt) [fine particles Dispersion 1] was obtained. The volume average particle diameter of the [fine particle dispersion 1] measured by LA-920 was 0.14 μm. A portion of [Fine Particle Dispersion 1] was dried to isolate the resin component.

990 parts of water, 83 parts of [fine particle dispersion 1], 37 parts of a 48.5% aqueous solution of dodecyl diphenyl ether disulfonate (Eleminol MON-7: manufactured by Sanyo Chemical Industries) and 90 parts of ethyl acetate are mixed and stirred to give a milky white liquid. Got. This was used as an aqueous medium.
In a beaker, 100 parts by weight of amorphous polyester 1, 10 parts by weight of crystalline polyester 1, 10 parts of polyester prepolymer, and 150 parts of ethyl acetate were stirred and dissolved. Next, 10 parts of carnauba wax 1 and 1.5 parts by weight of salicylic acid metal complex (E-84: Orient Chemical Industry) and 2.0 parts of silica A shown in Table 2 were added, and an ultraviscomil (bead mill) ( Using Imex Co., Ltd.), 3 passes under the condition that 80% by volume of zirconia beads having a particle diameter of 0.5 mm were filled at a liquid feeding speed of 1 kg / hour and a peripheral speed of the disk of 6 m / second.
Further, 2.7 parts of a ketimine compound was added and stirred to prepare a toner material liquid.
Add 250 parts of an aqueous medium to the container, add 100 parts of toner material solution while stirring at 12,000 rpm using a TK homomixer (manufactured by Koki Kogyo Co., Ltd.), and mix for 10 minutes to prepare an emulsified slurry. did.
In a Kolben equipped with a stirrer and a thermometer, 100 parts of an emulsified slurry was charged, and the solvent was removed at 30 ° C. for 12 hours while stirring at a stirring peripheral speed of 20 m / min to obtain a dispersed slurry.

After filtering 100 parts of the dispersion slurry under reduced pressure, 100 parts of ion-exchanged water was added to the filter cake, followed by mixing at 12000 rpm for 10 minutes using a TK homomixer, followed by filtration. To the obtained filter cake, 300 parts of ion-exchanged water was added, mixed for 10 minutes at 12000 rpm using a TK homomixer, and then filtered twice. 20 parts of a 10 wt% aqueous sodium hydroxide solution was added to the obtained filter cake, mixed at 12000 rpm for 30 minutes using a TK homomixer, and then filtered under reduced pressure. To the obtained filter cake, 300 parts of ion-exchanged water was added, mixed at 12000 rpm for 10 minutes using a TK homomixer, and then filtered. To the obtained filter cake, 300 parts of ion-exchanged water was added, mixed for 10 minutes at 12000 rpm using a TK homomixer, and then filtered twice. Further, 20 parts of 10 wt% hydrochloric acid was added to the obtained filter cake, and the mixture was mixed for 10 minutes at 12000 rpm using a TK homomixer, and then filtered. To the obtained filter cake, 300 parts of ion-exchanged water was added, mixed for 10 minutes at 12000 rpm using a TK homomixer, and then filtered twice to obtain a filter cake.
The obtained final filter cake was dried at 45 ° C. for 48 hours using a circulating dryer, and sieved with a mesh having a mesh size of 75 μm to obtain toner mother particles.
To 100 parts of the obtained toner base particles, 1.0 part of hydrophobic silica as an external additive and titanium oxide were mixed using a Henschel mixer (manufactured by Mitsui Mining) to prepare toner 1.

[Example 2]
<Toner 2>
Toner 2 was obtained in the same manner as toner 1 except that silica A contained in the oil phase of toner 1 was changed to silica B.

[Example 3]
<Toner 3>
Toner 3 was obtained in the same manner as toner 1 except that silica A contained in the oil phase of toner 1 was changed to silica C.

[Example 4]
<Toner 4>
Toner 4 was obtained in the same manner as toner 1 except that silica A contained in the oil phase of toner 1 was changed to silica D.

[Example 5]
<Toner 5>
Toner 5 was obtained in the same manner as toner 1 except that the amount was changed to 20 parts by weight of crystalline polyester 1 contained in the oil phase of toner 1.

[Example 6]
<Toner 6>
Toner 6 was obtained in the same manner as toner 1 except that the amount was changed to 22 parts by weight of crystalline polyester 12 contained in the oil phase of toner 1.

[Example 7]
<Toner 7>
Toner 7 was obtained in the same manner as toner 1 except that the crystalline polyester contained in the oil phase of toner 1 was changed to crystalline polyester 2.

[Example 8]
<Toner 8>
Toner 8 was obtained in the same manner as toner 7 except that silica A contained in the oil phase of toner 7 was changed to silica D.

[Example 9]
<Toner 9>
Toner 9 was obtained in the same manner as toner 1 except that the crystalline polyester contained in the oil phase of toner 1 was changed to crystalline polyester 3.

[Example 10]
<Toner 10>
Toner 10 was obtained in the same manner as toner 1 except that the crystalline polyester contained in the oil phase of toner 1 was changed to crystalline polyester 4.

[Example 11]
<Toner 11>
Toner 11 was obtained in the same manner as toner 1 except that the crystalline polyester contained in the oil phase of toner 1 was changed to crystalline polyester 5.

[Example 12]
<Toner 12>
Toner 12 was obtained in the same manner as toner 1 except that the crystalline polyester contained in the oil phase of toner 1 was changed to crystalline polyester 6.

[Example 13]
<Toner 13>
Toner 13 was obtained in the same manner as toner 1 except that it did not contain a polyester prepolymer in the oil phase of toner 1.

[Example 14]
<Toner 14>
Toner 14 was obtained in the same manner as toner 1 except that silica A contained in the oil phase of toner 1 was changed to silica E.

[Example 15]
<Toner 15>
Toner 15 was obtained in the same manner as toner 1 except that silica A contained in the oil phase of toner 1 was changed to silica F.

[Comparative Example 1]
<Toner 16>
A toner 16 was obtained in the same manner as the toner 1 except that the silica contained in the oil phase of the toner 1 was not contained.

[Comparative Example 2]
<Toner 17>
A toner 17 was obtained in the same manner as in the toner 1 except that the crystalline polyester contained in the oil phase of the toner 1 was not included.

[Comparative Example 3]
<Toner 18>
Toner 18 was obtained in the same manner as toner 1 except that silica A contained in the oil phase of toner 1 was changed to silica G.

  A developer composed of 5% by weight of toner subjected to external additive treatment and 95% by weight of a copper-zinc ferrite carrier coated with a silicone resin and having an average particle diameter of 40 μm can be prepared, and 45 sheets of A4 size paper can be printed per minute. Using Ricoh's imgio Neo 450, continuous printing was performed and evaluated according to the following criteria. The evaluation results are summarized in Table 3.

(Heat resistant storage stability)
The toner was stored at 50 ° C. for 8 hours and then sieved with a 42 mesh sieve for 2 minutes, and the residual rate on the wire mesh was measured.
At this time, the toner having better heat-resistant storage stability has a smaller remaining rate.
The heat-resistant storage stability is ◎ when the residual rate is less than 10%, ◯ when the residual rate is 10% or more and less than 20%, Δ when the residual rate is 20% or more and less than 25%, The case where the rate was 25% or more was determined as x.

[Gloss evaluation]
A solid image of a transparent toner having an adhesion amount of 0.4 mg / cm ² was formed and fixed at a fixing temperature of 180 ° C. and an NIP width of 20 mm, and the glossiness of the image was measured.
The paper used for the evaluation was POD gloss coated paper 128 g / m ² made by Oji Paper. Gloss is evaluated at 10 locations with a gloss of 60 degrees using a gloss meter VGS-1D manufactured by Nippon Denshoku Industries Co., Ltd., with average gloss of 70% or more, ◎, 50-70% ○, 40-50% △ , Less than 40% was taken as x.

(Low-temperature fixability evaluation)
A solid image of transparent toner with an adhesion amount of 0.4 mg / cm ² is formed, and the obtained sample image is not peeled off every 10,000 sheets, and the residual density of the image after the fixing pad is 85% or more ◎, those with an image density remaining rate of 70 to 85%, ◯, images withered, or those with an image density remaining rate of 70% or less.

(Filming evaluation method)
1. All toners and devices used for evaluation are left at 25 [° C.] in a 50% environment room for 1 day.
2. All the toner on the PCU of the copier is removed, leaving only the carrier in the developing device.
3. 28 [g] of transparent toner as a sample is put into a developing device including only a carrier, and 400 [g] of a developer having a toner concentration of 7 [%] is created.
4). A developing device is attached to the copying machine body, and only the developing device is idled for 5 [minutes] at a developing sleeve (sleeve forming the surface of the developing roller) at a linear speed of 300 [mm / s].
5. Both the developing sleeve and the photosensitive member are rotated by trailing at a target linear velocity, and the charging potential and the developing bias are adjusted so that the toner on the photosensitive member becomes 0.4 ± 0.05 [mg / cm ² ].
6). Under the above development conditions, the transfer current was adjusted so that the transfer rate was 96 ± 2 [%].
7). Full-page solid images were output continuously at 10,000 [sheets].
8). Observation of filming on photoconductor Evaluation criteria for filming property were as follows.
○: Excellent △: Normal ×: Very large

14 Image processing unit (IPU)
15 Writing unit 16 Paper feeding unit 17 Second paper feeding unit 21 Black (Bk) toner, developer photosensitive drum 22 Yellow (Y) toner, developer photosensitive drum 23 Magenta (M) toner, developer photosensitive drum Body drum 24 cyan (C) toner, developer photosensitive drum 25 transparent toner, developer photosensitive drum 31 black (Bk) toner, developer developing means 32 yellow (Y) toner, developer developing means 33 Magenta (M) toner, developer developing means 34 Cyan (C) toner, developer developing means 35 Transparent toner, developer image means 41 Black (Bk) toner, developer cleaning means 42 Yellow (Y) toner , Developer cleaning means 43 magenta (M) toner, developer cleaning means 44 cyan (C) toner, developer cleaning hand 45 Transparent toner, developer cleaning means 51 Black (Bk) toner, developer charging means 52 Yellow (Y) toner, developer charging means 53 Magenta (M) toner, developer charging means 54 Cyan (C) Toner, developer charging means 55 Transparent toner, developer charging means 61 Black (Bk) toner, developer transfer means 62 Yellow (Y) toner, developer transfer means 63 Magenta (M) toner, developer Transfer means 64 Cyan (C) toner, developer transfer means 65 Transparent toner, developer transfer means 66 Secondary transfer means 70 Transfer belt 80 Fixing unit 90 Recording medium reversing means

JP-A-4-278967 JP-A-4-362960 Japanese Patent Laid-Open No. 9-200551 JP-A-5-158364 Japanese Patent Laid-Open No. 8-220821 JP 2009-109926 A JP-A-4-338984 Japanese Patent Laid-Open No. 11-133665 JP 2002-287400 A JP 2002-351143 A

Claims (9)

  An electrophotographic transparent toner containing at least crystalline polyester, wherein the toner particles include silica in which a plurality of primary particles are fused to form secondary particles. Transparent toner. 2. The transparent toner for electrophotography according to claim 1, wherein the average coalescence degree G of silica in which a plurality of primary particles are coalesced to form secondary particles is 1.5 to 4.0. 3.
However, the adhesion degree G is defined by the following formula (1) where the silica primary particle diameter is D1 and the secondary particle diameter is D2.
Degree of adhesion G = D2 / D1 (Formula 1)   It is obtained by emulsifying and dispersing an oil phase obtained by dissolving and dispersing at least crystalline polyester and silica forming the secondary particles in an organic solvent in an aqueous medium containing a fine particle dispersant. The transparent toner for electrophotography according to claim 1, wherein the toner is transparent.   The transparent toner for electrophotography according to any one of claims 1 to 3, wherein the silica has an average secondary particle diameter Db of 80 nm to 200 nm.   The transparent toner for electrophotography according to claim 1, wherein the silica is contained in the oil phase.   The oil phase contains a binder resin component precursor composed of a modified polyester-based resin, and after the compound that extends or crosslinks with the binder resin component precursor is dissolved, the oil phase contains a fine particle dispersant. It is obtained by dispersing in an aqueous medium to obtain an emulsified dispersion, allowing the binder resin component precursor to undergo a crosslinking reaction and / or elongation reaction in the emulsified dispersion, and removing the organic solvent. The transparent toner for electrophotography according to any one of claims 1 to 5.   The transparent toner for electrophotography according to claim 1, wherein the toner contains 2 to 20% by weight of the crystalline polyester resin.   The transparent toner for electrophotography according to claim 1, wherein the crystalline polyester has a melting point of 55 to 85 ° C.   A toner set in which a transparent toner for electrophotography and a chromatic toner are combined, wherein the transparent toner for electrophotography contains at least a crystalline polyester, and the toner particles of the transparent toner are bonded to a plurality of primary particles. A toner set comprising a combination of a transparent toner for electrophotography and a chromatic toner, characterized in that it contains silica having secondary particles formed thereon.

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