JP2011112839A - Two-component developer and image forming method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a two-component developer which when a transparent toner excellent in low-temperature fixability is used, avoids carrier adhesion and can give an image with an even and uniform gloss, and to provide an image forming method using the same. <P>SOLUTION: The two-component developer includes a transparent toner having a binder resin and a release agent, and an electrophotographic carrier used for development of the transparent toner, wherein the electrophotographic carrier has volume resistivity of 10-14 (logΩ cm) and a magnetic moment in an applied magnetic field 1,000 (10<SP>3</SP>/4π×A/m) of 35-90 (Am<SP>2</SP>/kg). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a two-component developer used for developing a transparent toner and an image forming method using the same, and more particularly to a two-component developer for obtaining a glossy image by electrophotography and image formation using the same. It is about the method.

  In recent years, in the market of image forming apparatuses using electrophotography, in addition to those aimed at small offices and low power consumption for general offices, there are high-speed, high-reliability, high-quality products aimed at the commercial printing field. It has been developed and marketed.

  In the commercial printing field, there are many images, especially photographic image printing, and uniform gloss characteristics are required. In order to control the gloss, UV varnish printing, varnishing, PP pasting, and the like are generally performed. In these cases, UV varnish or the like is separately printed after normal color printing.

  In an electrophotographic image forming method, a full-color image is formed by superposing three or four color toners. Therefore, the glossiness differs depending on the glossiness of the paper in the image portion and the non-image portion, the glossiness of each toner color, and the toner adhesion amount per unit area. In the field of commercial printing, there is a problem because uniform gloss characteristics of photographic image portions are required.

  In order to make the glossiness of an image uniform in an electrophotographic image forming method, a method using a transparent toner (hereinafter referred to as a transparent toner) in combination with a color toner is disclosed in Patent Document 1, Patent Document 2, and Patent Document 3 proposes this.

  In these methods, the entire gloss is made uniform by developing transparent toner on the entire surface of the image or on a non-image portion. Therefore, the transparent toner consumes much more toner than the color toner. Therefore, the counter charge at the time of toner detachment becomes large, and the carrier adhesion to the non-image portion is likely to occur. In addition, since the transparent toner does not contain a pigment, it has a higher resistance than other color toners (color toners). When a carrier for other color toners is used, the developer becomes high resistance and becomes highly charged. Development failure occurs.

  As a method for adjusting the resistance of the carrier, it has been proposed to mix conductive carbon black in a coating layer made of silicon resin. For example, Patent Document 4 discloses a carrier coated with a material mainly composed of carbon black and a resin, and Patent Document 5 discloses a carrier containing porous carbon black in a coating layer. ing. In this way, when the carrier surface is coated with a resin containing a conductive substance, the resistance of the carrier can be easily adjusted. Further, Patent Document 6 discloses a carrier corresponding to a color toner provided with a surface coating layer containing a white conductive material instead of carbon black.

  The present invention has been made in view of the above problems in the prior art, and in using a transparent toner excellent in low-temperature fixability, an image having no uniform adhesion and uniform gloss can be obtained. It is an object to provide a two-component developer and an image forming method using the same.

In order to solve the above problems, the two-component developer and the image forming method using the same according to the present invention specifically have the technical features described in the following (1) to (8).
(1): a two-component developer comprising a transparent toner having a binder resin and a release agent, and an electrophotographic carrier used for developing the transparent toner, wherein the electrophotographic carrier has a core And a coating layer that covers the core material, the volume resistivity is 10 (log Ω · cm) or more and 14 (log Ω · cm) or less, and the applied magnetic field is 1000 (10 ³ / 4π · A / The two-component developer is characterized in that the magnetic moment in m) is 35 (Am ² / kg) or more and 90 (Am ² / kg) or less.

  By setting the magnetic moment within the above range, the retention force between the carrier particles is properly maintained, and the dispersion (mixing) of the toner into the carrier or developer and the ears of the developer formed during development are kept well. .

(2): The two-component developer according to (1) above, wherein the binder resin of the transparent toner is made of a thermoplastic resin containing a crystalline polyester resin.

  Using crystalline polyester enables low-temperature fixing and energy saving.

(3) The two-component developer according to (1) or (2) above, wherein the electrophotographic carrier has a volume average particle diameter of 20 μm or more and 65 μm or less.

  By making the volume average particle size in the above range, the effect of improving the carrier adhesion, image quality, etc. becomes remarkable.

(4): The coating layer according to any one of (1) to (3), wherein the coating layer contains a binder resin, and the binder resin of the coating layer contains a silicon resin. Two-component developer.

  When the binder resin of the carrier contains at least a silicon resin, spent toner components are effectively suppressed.

(5): Any of the above (1) to (4), wherein the coating layer contains a binder resin, and the binder resin of the coating layer is a mixed system of an acrylic resin and a silicon resin The two-component developer according to item 1.

  When the binder resin of the carrier is a mixed system of acrylic resin and silicon resin, the improvement effect such as adhesion of the coating layer becomes remarkable, and deterioration such as coating film scraping and film peeling is suppressed.

(6) The two-component developer described in any one of (1) to (5) above, wherein the transparent toner is made by a dissolution suspension method.

  A toner with a small particle size and a gorgeous particle shape distribution can be produced, and the image has high image quality.

(7): The transparent toner is obtained by melt-kneading a raw material containing a binder resin and a release agent to obtain a melt-kneaded product, and pulverizing and classifying the melt-kneaded product. The two-component developer according to any one of 1) to (5).

  Compared with the dissolution suspension method, the toner can be produced at a low cost.

(8): an electrostatic latent image forming step of forming an electrostatic latent image on the image carrier, a developing step of developing the electrostatic latent image with a developer to form a visible image, and the visible image And a step of fixing a visible image on the recording member to the recording member, wherein the developer includes one or more colors including a color toner and an electrophotographic carrier. A color toner developer, and a two-component developer containing the transparent toner according to any one of (1) to (7) above, wherein the transfer step places the transparent toner on the recording member. The image forming method is characterized in that the image is transferred so as to be positioned on the uppermost layer of the image.

  By fixing a transparent toner on a color image, the image can be glossy.

  According to the present invention, there is provided a two-component developer capable of obtaining an image having uniform gloss evenly without carrier adhesion when using a transparent toner excellent in low-temperature fixability, and an image forming method using the same. Can be provided.

It is the schematic which shows the structure of the carrier resistance measuring apparatus which measures the volume specific resistance of the carrier for electrophotography. 1 is a configuration diagram illustrating an example of an image forming apparatus for carrying out an image forming method according to the present invention. It is a block diagram which shows another example of the image forming apparatus for enforcing the image forming method which concerns on this invention.

  Hereinafter, the best mode for carrying out the present invention will be described based on the drawings as necessary. Note that it is easy for a person skilled in the art to make other embodiments by changing or correcting the present invention within the scope of the claims, and these changes and modifications are included in the scope of the claims. The following description is an example of the best mode of the present invention, and does not limit the scope of the claims.

  As described above, the electrophotographic carrier of the present invention is an electrophotographic carrier used for developing a transparent toner containing a binder resin and a release agent, and includes a core material and the core material. And having a volume resistivity of 10 (log Ω · cm) to 14 (log Ω · cm).

  The volume resistivity is preferably 10 (log Ω · cm) or more and 13.1 (log Ω · cm) or less.

Hereinafter, the present invention will be described in more detail.
Since the transparent toner in the present invention needs transparency, it contains no pigment or only a very small amount. Therefore, the resistance tends to be higher than that of normal color toner (hereinafter, color toner includes black toner). Therefore, when a carrier for color toner is used, the charge amount of the developer increases as compared with the case where color toner is used.
Further, since the transparent toner is used to give gloss to a photographic image or the like, the toner consumption is large and the charge amount is increased.

A highly charged developer is further charged after development, and the separation of the agent from the developing sleeve is deteriorated by the mirror image force. As a result, a phenomenon occurs in which the developer follows the developing sleeve. A problem that the image density in the rotation direction of the developing sleeve is lowered by taking around the developer whose toner density is lowered after the development. Higher image power is produced by the higher charge after development. To suppress this, the resistance of the carrier can be lowered. However, lowering the carrier resistance causes carrier development (solid carrier adhesion) due to electrostatic induction. Even if solid carrier adhesion is initially suppressed by some means, film scraping due to use proceeds and resistance is reduced, resulting in solid carrier adhesion. It has been difficult to prevent the developer from being carried around the developing sleeve, to prevent the solid carrier from adhering, and to extend the life of the developer.
In contrast, as a result of intensive studies, the present inventors have found that the problem can be solved by adjusting the volume specific resistance of the carrier to 10 (log Ω · cm) or more and 14 (log Ω · cm) or less.

  The adjustment of the volume resistivity can be managed by adjusting the material of the core material of the electrophotographic carrier, the thickness of the coating layer, and the content of the conductive particles in the coating layer.

The volume resistivity of the electrophotographic carrier in the present invention is measured by the carrier resistance measuring apparatus shown in the schematic diagram of FIG. 1, and is 10 (log Ω · cm) or more and 14 (Log Ω · cm) or less, preferably 10 (log Ω). · Cm) or more and 13.1 (LogΩ · cm) or less is preferable, and is not particularly limited as long as it is within this range, and can be adjusted according to the use.
This is not preferable when the volume resistivity is less than 10 (Log Ω · cm) and carrier adhesion occurs in the non-image area.
On the other hand, when the volume resistivity exceeds 14 (Log Ω · cm), the edge effect deteriorates to an unacceptable level, which is not preferable. Further, it is not preferable because carrier adhesion occurs in the image edge portion.
In addition, when it falls below the measurable lower limit of the high resist meter, the volume specific resistance value is not substantially obtained, and it will be treated as a breakdown.

Specifically, the volume resistivity referred to in the present invention is measured by the following measuring apparatus and measuring method.
First, a carrier (33) is formed in a cell (31) made of a fluororesin container containing an electrode (32a) having a distance of 2 mm between electrodes (32a) and (32b) and a surface area of 2 cm × 4 cm and an electrode (32b) as shown in FIG. ), And a tapping operation is performed for 1 minute at a tapping speed of 30 times / min. Using a tapping machine PTM-1 type manufactured by Sankyo Piotech. Next, a DC voltage of 1000 V was applied between the two electrodes, the DC resistance was measured with a high resistance meter 4329A (4329A + LJK5HVLVWDQFH0HWHU; manufactured by Yokogawa Hewlett-Packard Co., Ltd.), the electric resistivity R (Ω · cm) was obtained, and LogR was calculated. Measure the volume resistivity.

As described above, the electrophotographic carrier in the present invention preferably has a coating layer containing a binder resin and conductive fine particles on the carrier core material.
As the carrier core material in the present invention (hereinafter sometimes abbreviated as “core material”), those known as two-component carriers for electrophotography, such as ferrite, Cu—Zn ferrite, Mn ferrite, and Mn—Mg. Ferrite, Mn—Mg—Sr ferrite, magnetite, iron, nickel, and the like may be appropriately selected and used according to the use and purpose of use of the carrier, and are not limited to the exemplified materials.

  The volume average particle size of the electrophotographic carrier in the present invention is preferably 20 μm or more and 65 μm or less. When the volume average particle size is 20 μm or more and 65 μm or less, the effect of improving the carrier adhesion and the image quality is remarkable. This is not preferable when the volume average particle size is less than 20 μm, since problems such as carrier adhesion occur due to a decrease in the uniformity of the particles and a lack of sufficient technology on the machine side. On the other hand, if it exceeds 65 μm, the reproducibility of image details is poor and a fine image cannot be obtained.

  The volume average particle diameter of the electrophotographic carrier can be measured using an SRA type of Microtrac particle size analyzer (manufactured by Nikkiso Co., Ltd.). What was performed by the range setting of 0.7 micrometer or more and 125 micrometers or less is used. Further, methanol is used for the dispersion liquid, and the refractive index is set to 1.33, and the refractive indexes of the electrophotographic carrier and the core material are set to 2.42.

  Furthermore, it is preferable that at least a silicon resin is contained as the binder resin in the coating layer of the electrophotographic carrier. The improvement effect is remarkable when the binder resin in the coating layer of the electrophotographic carrier is at least a silicon resin. This is because the silicone resin has a low surface energy, so that it is difficult for the toner component to be spent and film scraping occurs, so that it is difficult to accumulate the spent component.

  Silicone resin as used in the present invention refers to all generally known silicon resins, such as straight silicon consisting only of organosilosan bonds and silicon resins modified with alkyd, polyester, epoxy, acrylic, urethane, etc. Although it is mentioned, it is not restricted to these.

  For example, taking a commercial product as an example, examples of the straight silicone resin include KR271, KR255, KR152 manufactured by Shin-Etsu Chemical, SR2400, SR2406, SR2410 manufactured by Toray Dow Corning Silicon Co., etc. In this case, it is possible to use the silicon resin alone, but it is also possible to simultaneously use other components that undergo a crosslinking reaction, charge amount adjusting components, and the like. Further, as modified silicone resin, KR206 (alkyd modified), KR5208 (acryl modified), ES1001N (epoxy modified), KR305 (urethane modified) manufactured by Shin-Etsu Chemical, SR2115 (epoxy modified) manufactured by Toray Dow Corning Silicon Co., Ltd. , SR2110 (alkyd modified) and the like.

  Further, a mixed system of an acrylic resin and a silicon resin can be used as the binder resin in the coating layer of the electrophotographic carrier. It is preferable to use an acrylic resin in combination with the silicon resin because an improvement effect such as adhesion of the coating layer becomes remarkable. In other words, since acrylic resin has strong adhesiveness and low brittleness, it has a very excellent property of abrasion resistance, it is difficult to cause deterioration such as film scraping and film peeling of the coating layer, and the coating layer is stably maintained. In addition, the particles contained in the coating layer such as conductive fine particles can be firmly held due to the strong adhesiveness. In particular, a powerful effect can be exerted in holding fine particles having a particle size larger than the coating layer thickness.

  The acrylic resin referred to in the present invention refers to all resins having an acrylic component, and is not particularly limited. Moreover, it is possible to use the acrylic resin alone, and it is also possible to simultaneously use at least one other component that undergoes a crosslinking reaction with the acrylic resin. Examples of other components that undergo a crosslinking reaction include amino resins and acidic catalysts, but are not limited thereto.

  Examples of the amino resin include guanamine and melamine resin, but are not limited thereto. In addition, as the acidic catalyst, any having a catalytic action can be used. For example, it has a reactive group such as a fully alkylated type, a methylol group type, an imino group type, and a methylol / imino group type, but is not limited thereto.

  As mentioned above, acrylic resin has a very good property of abrasion resistance due to its strong adhesiveness and low brittleness, but on the other hand, its surface energy is high, so in combination with easily spent toner, Problems such as a decrease in charge amount due to spent (accumulation) may occur. In this case, this problem can be solved by using together a silicon resin that has an effect that it is difficult to spend the toner component due to the low surface energy and the accumulation of the spent component is difficult to progress due to film scraping. However, since silicon resin has weak adhesiveness and high brittleness, it also has a weak point that it has poor wear resistance. Therefore, it is important to obtain a good balance between the properties of these two types of resins, which makes it difficult to spend. It is possible to obtain a coating layer having wear characteristics.

  In addition, by including conductive particles in the binder resin constituting the coating layer of the electrophotographic carrier in the present invention, the volume resistivity of 10 (log Ω · cm) to 14 (Log Ω · cm) is set. Can do.

  Specifically, the conductive particles are preferably particles containing at least one kind of particles selected from carbon black, magnetite, graphite, zinc oxide, tin oxide, titanium, and alumina. In particular, as the conductive particles, carbon black can be preferably used without inhibiting the irregularities caused by the fine particles on the surface of the electrophotographic carrier because of its small particle size. The particle diameter of the conductive particles has a peak value of 10 to 500 nm (more preferably 20 to 200 nm) on the basis of the number, so that the residual charge on the surface of the electrophotographic carrier can be removed well and the electrophotographic carrier can be removed. It is preferable in order to satisfactorily prevent the desorption.

Furthermore, the electrophotographic carrier in the present invention preferably has a magnetic moment of 35 (Am ² / kg) or more and 90 (Am ² / kg) or less in an applied magnetic field 1000 (10 ³ / 4π · A / m). .
Hereinafter, the strength of the applied magnetic field may be expressed by Oe (Oersted). Note that 1000 (10 ³ / 4π · A / m) is 1 KOe (1000 oersted).

By setting the magnetic moment within the above range, the coercive force between the electrophotographic carrier particles can be appropriately maintained, so that the dispersion (mixing) of the toner in the electrophotographic carrier or the developer is quickly improved. If the magnetic moment at is less than 40 Am ² / kg, carrier adhesion occurs due to insufficient magnetic moment, which is not preferable. On the other hand, when the magnetic moment at 1 KOe exceeds 90 Am ² / kg, the ears of the developer formed at the time of development become too hard, so that the reproducibility of image details is poor and a fine image cannot be obtained, which is not preferable.
A method for measuring the magnetic moment will be described later.

Next, details of the transparent toner and the color toner used in the present invention will be described.
[Toner Production Method]
The toner used in the present invention can be produced by the following method, but is not limited thereto.
The transparent toner and color toner used in the present invention can be manufactured by a pulverized toner manufacturing method (pulverizing method) or a suspension polymerization method.

(Production method of pulverized toner)
In order to produce the transparent toner and the color toner (chromatic toner) in the present invention, a binder resin (fixing resin), a release agent, a lubricant, a colorant as necessary, and a charge control agent, a lubricant as necessary. In addition, the fixing resin in which the additives are uniformly dispersed is combined and mixed thoroughly by a mixer such as a Henschel mixer or a super mixer, and then melted and kneaded using a hot melt kneader such as a heating roll, kneader or extruder. After sufficiently mixing the materials (materials), the mixture is cooled and solidified, and then finely pulverized and classified to obtain a toner. The pulverization method at this time includes a jet mill method in which toner is included in a high-speed air stream, the toner collides with an impact plate and pulverizes with the energy, an inter-particle collision method in which toner particles collide with each other in the air flow, and further at high speed. A mechanical pulverization method in which toner is supplied and pulverized between a rotated rotor and a narrow gap can be used.

  In addition, an oil phase in which a toner material is dissolved or dispersed in an organic solvent phase is dispersed in an aqueous medium phase, a resin is reacted, and then the solvent is removed, followed by filtration, washing, and drying, thereby forming a toner base. A solution suspension method for producing particles is also possible.

  In order to improve the fluidity, storage stability, developability, and transferability of the toner, inorganic fine particles such as hydrophobic silica fine powder may be further added to and mixed with the toner manufactured as described above. For mixing the additives, a general powder mixer is used, but it is preferable to equip a jacket or the like to adjust the internal temperature. In order to change the load history applied to the additive, the additive may be added midway or gradually. In this case, you may change the rotation speed, rolling speed, time, temperature, etc. of a mixer. Also, a strong load may be given first, then a relatively weak load, or vice versa. Examples of the mixing equipment that can be used include a V-type mixer, a rocking mixer, a Ladige mixer, a Nauter mixer, and a Henschel mixer. Next, the toner is obtained by passing through a sieve of 250 mesh or more to remove coarse particles and aggregated particles.

In addition to the non-crystalline and crystalline polyester as the binder resin, the transparent toner material includes a charge control agent, a colorant, an additive, a wax, a fluidity improver, a cleaning property improver, and a magnetic material as necessary. Materials, metal soaps, etc. can be added.
The color toner material includes a resin material known as a binder resin, and other charge control agents, colorants, additives, waxes, fluidity improvers, and cleaning property improvers that are the same as the transparent toner material. Magnetic materials, metal soaps, etc. can be added.
Hereinafter, the transparent toner material and the color toner material will be described in detail.

(Toner binder resin)
As the binder resin, a transparent polyester binder resin for transparent toner, a color developing property as a binder resin for full-color toner, and a crystalline polyester resin, an amorphous polyester resin, particularly non-crystalline polyester, which are also preferable in terms of image strength. A more preferred polyester resin is used. On the other hand, crystalline polyester is excellent in low-temperature fixability. Glossy images with transparent toner and normal color images have several types of toner layers stacked on top of each other, so the toner layers become thicker, resulting in cracks and defects in the images due to insufficient strength of the toner layers. The gloss is lost. For this reason, a polyester resin is used to maintain an appropriate gloss and excellent strength.

The polyester resin can be generally obtained by an esterification reaction of a polyhydric alcohol and a polycarboxylic acid.
Among the monomers constituting the polyester resin, the alcohol monomer includes a trifunctional or higher polyfunctional monomer, for example, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene. Diols such as glycol, 1,4-butadieneol, neopentyl glycol, 1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol; bisphenol A, hydrogenated bisphenol A, polyoxypropylene Bisphenol A alkylene oxide adducts such as bisphenol A; other dihydric alcohols or sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tri Enterythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, diglycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, tri Examples include methylolpropane, 1,3,5-trihydroxybenzene, and other trihydric or higher polyhydric alcohols.

  Among these monomers, those using a bisphenol A alkylene oxide adduct as a main component monomer are particularly preferably used. When the bisphenol A alkylene oxide adduct is used as a constituent monomer, a polyester having a relatively high glass transition point is obtained due to the nature of the bisphenol A skeleton, and the copy blocking resistance and heat resistant storage stability are good. In addition, the presence of alkyl groups on both sides of the bisphenol A skeleton acts as a soft segment in the polymer, and the color developability and image strength during toner fixing are improved. Of the bisphenol A alkylene oxide adducts, those having an ethylene group or a propylene group are preferably used.

  Among the monomers constituting the polyester resin, acid monomers include, for example, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipine Alkenyl succinic acids or alkyl succinic acids such as acids, sebacic acid, azelaic acid, malonic acid, n-dodecenyl succinic acid, n-dodecyl succinic acid, anhydrides, alkyl esters of these acids, or other divalent carboxylic acids; 1,2,4-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxylic acid Lu-2-methyl-methylenecarboxypropane, tetra (methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid, empole trimer acid, or anhydrides thereof, alkyl ester, alkenyl ester, aryl ester Or other trivalent or higher carboxylic acids.

  Specific examples of the alkyl group, alkenyl group or aryl ester include 1,2,4-benzenetricarboxylic acid, trimethyl 1,2,4-benzenetricarboxylate, triethyl 1,2,4-benzenetricarboxylate, 1,2 , 4-benzenetricarboxylic acid tri-n-butyl, 1,2,4-benzenetricarboxylic acid isobutyl, 1,2,4-benzenetricarboxylic acid tri-n-octyl, 1,2,4-benzenetricarboxylic acid tri-2-ethylhexyl, 1,2,4-benzenetricarboxylic acid tribenzyl, 1,2,4-benzenetricarboxylic acid tris (4-isopropylbenzyl), and the like.

  Further, in the present invention, a polycondensation polyester resin can also be preferably used as the binder resin used in the toner. Examples include polyester resins (AX) and (AX), which are polycondensates of polyols and polycarboxylic acids, and modified polyester resins (AY) obtained by further reacting polyepoxides (C) and the like. (AX), (AY) and the like may be used alone or in combination of two or more.

  Examples of the polyol include a diol (g) and a trivalent or higher polyol (h), and examples of the polycarboxylic acid include a dicarboxylic acid (i) and a trivalent or higher polycarboxylic acid (j). You may use together. Examples of the polyester resins (AX) and (AY) include the following, and these can also be used in combination.

(AX1): Linear polyester resin using (g) and (i) (AX2): Non-linear polyester resin using (h) and / or (j) together with (g) and (i) ( AY1): Modified polyester resin obtained by reacting (AX2) with (c)

  As the diol (g), those having a hydroxyl value of 180 to 1900 (mg KOH / g, the same applies hereinafter) are preferable. Specifically, alkylene glycol having 2 to 36 carbon atoms (ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butylene glycol, 1,6-hexanediol, etc.); 4 to 36 alkylene ether glycols (such as diethylene glycol, triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol and polybutylene glycol); alicyclic diols having 6 to 36 carbon atoms (1,4-cyclohexanedimethanol and hydrogen) Added bisphenol A and the like; an alkylene oxide having 2 to 4 carbon atoms of the above alicyclic diol (ethylene oxide (hereinafter abbreviated as EO), propylene oxide (hereinafter abbreviated as PO) and putylene oxide (hereinafter referred to as BO). Adducts (addition mole number 1-30); adducts (additions) of bisphenols (bisphenol A, bisphenol F, bisphenol S, etc.) having 2 to 4 carbon atoms alkylene oxides (EO, PO, BO, etc.) Mole number 2-30) etc. are mentioned.

Of these, preferred are alkylene glycols having 2 to 12 carbon atoms, alkylene oxide adducts of bisphenols, and combinations thereof. Particularly preferred are alkylene oxide adducts of bisphenols, alkylene glycols having 2 to 4 carbon atoms. And a combination of two or more of these.
In the above and below, the hydroxyl value and the acid value are measured by the methods specified in JISK0070.

  As the trivalent or higher (3 to 8 or higher) polyol (h), those having a hydroxyl value of 150 to 1900 are preferable. Specifically, an aliphatic polyhydric alcohol having 3 to 36 or more carbon atoms having 3 to 8 carbon atoms (an alkane polyol and an intramolecular or intermolecular dehydrate thereof such as glycerin, triethylolethane, pentaerythritol, sorbitol, Sorbitan, polyglycerin, and dipentaerythritol; sugars and derivatives thereof such as sucrose and methyl glucoside; and the like; adducts of the above aliphatic polyhydric alcohols having 2 to 4 carbon atoms (such as EO, PO, and BO) Addition mole number 1-30); Trisphenol (trisphenol PA, etc.) adduct of C2-C4 alkylene oxide (EO, PO, BO, etc.) (addition mole number 2-30); Novolac resin (phenol novolac) And cresol novolak, etc .: average degree of polymerization of 3 Alkylene oxides having 2 to 4 carbon atoms 0) (EO, PO, BO, etc.) adducts (added mole number 2 to 30), and the like.

  Among these, preferred are 3 to 8 or higher aliphatic polyhydric alcohols and alkylene oxide adducts of novolac resins (addition mole number: 2 to 30), and particularly preferred are alkylene oxide adducts of novolak resins. It is.

  As the dicarboxylic acid (i), those having an acid value of 180 to 1250 (mg KOH / g, the same applies hereinafter) are preferable. Specifically, alkane dicarboxylic acids having 4 to 36 carbon atoms (such as succinic acid, adipic acid, and sebacic acid) and alkenyl succinic acids (such as dodecenyl succinic acid); alicyclic dicarboxylic acids having 4 to 36 carbon atoms [dimer acid] (Dimerized linoleic acid) etc.]; C4-C36 alkene dicarboxylic acid (maleic acid, fumaric acid, citraconic acid, mesaconic acid, etc.); C8-36 aromatic dicarboxylic acid (phthalic acid, isophthalic acid) , Terephthalic acid, and naphthalenedicarboxylic acid). Of these, preferred are alkene dicarboxylic acids having 4 to 20 carbon atoms and aromatic dicarboxylic acids having 8 to 20 carbon atoms. As (i), acid anhydrides or lower alkyl (carbon number 1 to 4) esters (methyl ester, ethyl ester, isopropyl ester, etc.) described above may be used.

  The trivalent or higher (3 to 6 or higher) polycarboxylic acid (j) preferably has an acid value of 150 to 1250 mg. Specifically, an aromatic polycarboxylic acid having 9 to 20 carbon atoms (trimellitic acid, pyromellitic acid, etc.); vinyl polymer of unsaturated carboxylic acid [number average molecular weight (hereinafter referred to as Mn, gel permeation chromatography) (By GPC): 450-10000] (styrene / maleic acid copolymer, styrene / acrylic acid copolymer, α-olefin / maleic acid copolymer, styrene / fumaric acid copolymer, etc.), and the like. . Among these, preferred are aromatic polycarboxylic acids having 9 to 20 carbon atoms, and particularly preferred are trimellitic acid and pyromellitic acid. As the trivalent or higher polycarboxylic acid (j), acid anhydrides or lower alkyl (1 to 4 carbon atoms) esters (methyl ester, ethyl ester, isopropyl ester, etc.) described above may be used.

  Further, together with (g), (h), (i) and (j), an aliphatic or aromatic hydroxycarboxylic acid (k) having 4 to 20 carbon atoms and a lactone (l) having 6 to 12 carbon atoms are copolymerized. You can also.

  Examples of the hydroxycarboxylic acid (k) include hydroxystearic acid and hydrogenated castor oil fatty acid. Examples of the lactone (l) include caprolactone.

  Examples of the polyepoxide (c) include polyglycidyl ether [ethylene glycol diglycidyl ether, tetramethylene glycol diglycidyl ether, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, glycerin triglycidyl ether, pentaerythritol tetraglycidyl ether, phenol novolac ( Average polymerization degree 3 to 60) glycidyl etherified compound, etc.]; diene oxide (pentadiene dioxide, hexadiene dioxide, etc.) and the like. Among these, polyglycidyl ether is preferable, and ethylene glycol diglycidyl ether and bisphenol A diglycidyl ether are more preferable.

  The number of epoxy groups per molecule of (c) is preferably 2-8, more preferably 2-6, and particularly preferably 2-4.

  The epoxy equivalent of (c) is preferably 50 to 500. The lower limit is more preferably 70, particularly preferably 80, and the upper limit is more preferably 300, particularly preferably 200. When the number of epoxy groups and the epoxy equivalent are within the above ranges, both developability and fixability are good. It is more preferable if the above-mentioned ranges of the number of epoxy groups per molecule and the epoxy equivalent are satisfied at the same time.

  The reaction ratio of the polyol and the polycarboxylic acid is preferably 2/1 to 1/2, more preferably 1.5 / 1, as an equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] and the carboxyl group [COOH]. ˜1 / 1.3, particularly preferably 1.3 / 1 to 1 / 1.2. The types of polyol and polycarboxylic acid to be used are selected in consideration of molecular weight adjustment so that the glass transition point of the polyester toner binder to be finally adjusted is 45 to 85 ° C.

  In the present invention, the amorphous polyester resin used as the toner binder (toner binder resin) can be produced in the same manner as in the usual polyester production method. For example, the reaction temperature is preferably 150 to 280 ° C, more preferably 160 to 250 ° C, and particularly preferably 170 to 240 ° C in the presence of a titanium-containing catalyst (a) in an inert gas (nitrogen gas or the like) atmosphere. It can be performed by reacting. The reaction time is preferably 30 minutes or longer, particularly 2 to 40 hours from the viewpoint of reliably performing the polycondensation reaction. It is also effective to reduce the pressure (for example, 1 to 50 mmHg) in order to improve the reaction rate at the end of the reaction.

  The addition amount of the titanium-containing catalyst (a) is preferably 0.0001 to 0.8%, more preferably 0.0002 to 0.6 based on the weight of the polymer obtained from the viewpoint of polymerization activity and the like. %, Particularly preferably 0.0015 to 0.55%.

  In addition, other esterification catalysts can be used in combination as long as the catalytic effect of (a) is not impaired. Examples of other esterification catalysts include tin-containing catalysts (eg, dibutyltin oxide), antimony trioxide, titanium-containing catalysts other than (a) (eg, titanium alkoxide, potassium titanyl oxalate, and titanium terephthalate), zirconium-containing catalysts (Eg zirconyl acetate), germanium-containing catalysts, alkali (earth) metal catalysts (eg alkali metal or alkaline earth metal carboxylates: lithium acetate, sodium acetate, potassium acetate, calcium acetate, sodium benzoate, and benzoic acid Potassium), and zinc acetate. The addition amount of these other butterflies is preferably 0 to 0.6% based on the weight of the polymer obtained. By making it within 0.6%, the coloration of the polyester resin is reduced, which is preferable for use in color toners. The content of (a) in all the added catalysts is preferably 50 to 100%.

  Examples of the method for producing the linear polyester resin (AX1) include a diol in the presence of 0.0001 to 0.8% of the catalyst (a) and, if necessary, another catalyst based on the weight of the obtained polymer. (G) and the dicarboxylic acid (i) are heated to 180 ° C. to 260 ° C. and subjected to dehydration condensation under normal pressure and / or reduced pressure conditions to obtain (AX1).

  As a method for producing the non-linear polyester resin (AX2), for example, 0.0001 to 0.8% of the catalyst (a) with respect to the weight of the obtained polymer, and if necessary, in the presence of another catalyst, Diol (g), dicarboxylic acid (i), and trihydric or higher polyol (h) are heated to 180 ° C. to 260 ° C. and subjected to dehydration condensation under normal pressure and / or reduced pressure conditions. The method of reacting polycarboxylic acid (j) and obtaining (AX2) is mentioned. (J) can also be reacted simultaneously with (g), (i) and (h).

  Examples of the method for producing the modified polyester resin (AY1) include a method of obtaining (AY1) by adding a polyepoxide (c) to the polyester resin (AX2) and performing a molecular extension reaction of the polyester at 180 ° C. to 260 ° C. .

  The acid value of (AX2) to be reacted with (c) is preferably 1 to 60, more preferably 5 to 50. When the acid value is 1 or more, (c) remains unreacted and does not adversely affect the performance of the resin, and when it is 60 or less, the thermal stability of the resin is good.

  In addition, the amount of (c) used to obtain (AY1) is preferably 0.01 to 10%, more preferably 0.8% with respect to (AX2), from the viewpoints of low-temperature fixability and hot offset resistance. 05 to 5%.

  In the present invention, the toner binder (toner binder resin) may contain other resins, if necessary, in addition to the polyester resin described above. Other resins include styrene resins (such as copolymers of styrene and alkyl (meth) acrylate, copolymers of styrene and diene monomers), epoxy resins (such as bisphenol A diglycidyl ether ring-opening polymer), Examples thereof include urethane resins (diols and / or polyaddition products of trivalent or higher polyols and diisocyanates, etc.). The content of the other resin in the toner binder is preferably 0 to 40% by weight, more preferably 0 to 30% by weight, and particularly preferably 0 to 20% by weight.

(Crystalline polyester)

  The crystalline polyester resin (crystalline polyester resin) A used in the present invention is composed of a crystalline aliphatic polyester resin containing an ester bond represented by the following general formula (2) in its molecular main chain. And

_{-OOC-R-COO- (CH 2} ) n- ··· formula (2)

  In the general formula (2), R represents a linear unsaturated aliphatic divalent carboxylic acid residue, and is a linear unsaturated aliphatic group having 2 to 20 carbon atoms, preferably 2 to 4 carbon atoms. n is an integer of 2 to 20, preferably 2 to 6.

  The presence of the structure of the general formula (2) can be confirmed by solid-state C13 NMR (nuclear magnetic resonance analysis).

  Further, it is more preferably a crystalline aliphatic polyester resin containing at least 60 mol% of ester bonds in the molecular main chain.

  Specific examples of the linear unsaturated aliphatic group include linear unsaturated divalent carboxylic acids such as maleic acid, fumaric acid, 1,3-n-propene dicarboxylic acid, and 1,4-n-butene dicarboxylic acid. Mention may be made of linear unsaturated aliphatic groups derived from acids.

In the general formula (2), (CH ₂ ) n represents a linear aliphatic dihydric alcohol residue.
Specific examples of the linear aliphatic dihydric alcohol residue in this case include linear aliphatic 2 such as ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, and 1,6-hexanediol. Those derived from dihydric alcohols can be indicated. Since the polyester resin (A) uses a linear unsaturated aliphatic dicarboxylic acid as the acid component, the polyester resin (A) exhibits an effect that a crystal structure is easily formed as compared with the case where an aromatic dicarboxylic acid is used.

  The polyester resin comprises (i) a polyvalent carboxylic acid component comprising a linear unsaturated aliphatic divalent carboxylic acid or a reactive derivative thereof (an acid anhydride, a lower alkyl ester having 1 to 4 carbon atoms, an acid halide, etc.) (Ii) A polyhydric alcohol component composed of a linear aliphatic diol can be produced by a polycondensation reaction by a conventional method.

  In this case, a small amount of other polyvalent carboxylic acid can be added to the polyvalent carboxylic acid component as necessary. In this case, the polyvalent carboxylic acid includes (i) an unsaturated aliphatic divalent carboxylic acid having a branched chain, (ii) a saturated aliphatic divalent carboxylic acid, and a saturated aliphatic trivalent carboxylic acid. In addition to polyvalent carboxylic acids, (iii) aromatic polyvalent carboxylic acids such as aromatic divalent carboxylic acids and aromatic trivalent carboxylic acids are included. The addition amount of these polyvalent carboxylic acids is usually 30 mol% or less, preferably 10 mol% or less, based on the total carboxylic acid, and is appropriately added within the range where the resulting polyester has crystallinity.

  Specific examples of polyvalent carboxylic acids that can be added as needed include malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, citraconic acid, phthalic acid, isophthalic acid, terephthalic acid, etc. A divalent carboxylic acid of: trimethic anhydride, 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, And trivalent or higher polyvalent carboxylic acids such as 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methylenecarboxypropane, 1,2,7,8-octanetetracarboxylic acid, etc. it can.

  A trivalent or higher polyhydric alcohol can be added to the polyhydric alcohol component, if necessary, in addition to a small amount of an aliphatic branched dihydric alcohol or cyclic dihydric alcohol. The addition amount is 30 mol% or less, preferably 10 mol% or less, based on the total alcohol, and is appropriately added within the range in which the resulting polyester has crystallinity.

  Examples of polyhydric alcohol added as needed include 1,4-bis (hydroxymethyl) cyclohexane, polyethylene glycol, bisphenol A ethylene oxide adduct, bisphenol A propylene oxide adduct, glycerin and the like.

  In the polyester resin, the molecular weight distribution is preferably sharp from the viewpoint of low-temperature fixability, and the molecular weight is preferably a relatively low molecular weight. As for the molecular weight of the polyester resin (A), the weight average molecular weight (Mw) is 5500-6500, the number average molecular weight (Mn) is 1300-1500 and The Mw / Mn ratio is preferably 2-5.

  The molecular weight distribution of the polyester resin (A) is based on a molecular weight distribution diagram in which the horizontal axis is log (M: molecular weight) and the vertical axis is weight%. In the case of the polyester resin (A) used in the present invention, in this molecular weight distribution diagram, it is preferable to have a molecular weight peak in the range of 3.5 to 4.0 (wt%), and the half width of the peak is 1. 5 or less is preferable.

  In the polyester resin, the glass transition temperature (Tg) and the softening temperature (Tm) are desirably low as long as the heat resistant storage stability of the toner is not deteriorated. In general, the Tg is 80 to 130 ° C., preferably It is 80-125 degreeC, The Tm is 80-130 degreeC, Preferably it is 80-125 degreeC. When Tg and Tm are higher than the above ranges, the lower fixing temperature of the toner is increased, so that the low temperature fixability of the toner is deteriorated.

  When two or more kinds of polyester resins are used in combination, and when at least one kind of polyester resin and another resin are mixed, powder mixing or melt mixing may be performed in advance, or they may be mixed at the time of toner formation. The temperature in the case of melt mixing is preferably 80 to 180 ° C, more preferably 100 to 170 ° C, and particularly preferably 120 to 160 ° C.

  If the mixing temperature is too low, sufficient mixing cannot be achieved, which may result in non-uniformity. When two or more kinds of polyester resins are mixed, if the mixing temperature is too high, averaging due to transesterification occurs, so that the resin physical properties necessary as a toner binder may not be maintained.

  The mixing time in the case of melt mixing is preferably 10 seconds to 30 minutes, more preferably 20 seconds to 10 minutes, and particularly preferably 30 seconds to 5 minutes. When two or more kinds of polyester resins are mixed, if the mixing time is too long, averaging due to transesterification occurs, so that the resin physical properties necessary as a toner binder may not be maintained.

  Examples of the mixing device in the case of melt mixing include a batch type mixing device such as a reaction tank and a continuous mixing device. In order to uniformly mix at an appropriate temperature in a short time, a continuous mixing device is preferable.

  Examples of the continuous mixing device include an extruder, a continuous kneader, and a three roll. Of these, extruders and container kneaders are preferred.

In the case of powder mixing, it can be mixed with normal mixing conditions and mixing equipment.
As mixing conditions in the case of powder mixing, the mixing temperature is preferably 0 to 80 ° C, more preferably 10 to 60 ° C. The mixing time is preferably 3 minutes or more, more preferably 5 to 60 minutes. Examples of the mixing device include a Henschel mixer, a Nauter mixer, and a bumper mixer. A Henschel mixer is preferable. The acid value of the crystalline polyester resin is preferably 20 mgKOH / g or more in order to achieve the desired low-temperature fixability from the viewpoint of the affinity between the paper and the resin, In order to improve hot offset property, it is preferable that it is 45 mgKOH / g or less. Further, the hydroxyl value of the crystalline polyester resin is preferably 5 to 50 mgKOH / g in order to achieve a predetermined low-temperature fixability and good charging characteristics.

(Charge control agent)
The transparent toner and color toner used in the present invention can contain a charge control agent in the toner, if necessary.
For example, nigrosine, azine dyes containing an alkyl group having 2 to 16 carbon atoms (Japanese Patent Publication No. 42-1627), basic dyes such as C.I. I. BasicYello2 (C.I. 41000), C.I. I. BasicYello3, C.I. I. BasicRed1 (C.I. 45160), C.I. I. Basic Red 9 (C.I. 42500), C.I. I. BasicViolet 1 (C.I. 42535), C.I. I. BasicViolet 3 (C.I. 42555), C.I. I. BasicViolet 10 (C.I. 45170), C.I. I. BasicViolet 14 (C.I. 42510), C.I. I. BasicBlue 1 (C.I. 42025), C.I. I. BasicBlue 3 (C.I. 51005), C.I. I. BasicBlue 5 (C.I. 42140), C.I. I. BasicBlue 7 (C.I. 42595), C.I. I. BasicBlue 9 (C.I. 52015), C.I. I. BasicBlue 24 (C.I. 52030), C.I. I. BasicBlue 25 (C.I. 52025), C.I. I. BasicBlue 26 (C.I. 44045), C.I. I. BasicGreen1 (C.I.42040), C.I. I. Lake pigments of these basic dyes, such as BasicGreen 4 (C.I. 42000), C.I. I. Solvent Black 8 (C.I. 26150), quaternary ammonium salts such as benzoylmethyl hexadecyl ammonium chloride, decyl trimethyl chloride, or dialkyl tin compounds such as dibutyl or dioctyl, dialkyl tin borate compounds, guanidine derivatives, vinyls containing amino groups Polymers, polyamine resins such as condensation polymers containing amino groups, described in JP-B No. 41-20153, JP-B No. 43-27596, JP-B No. 44-6397, JP-B No. 45-26478 Metal complex salts of monoazo dyes, salicylic acid, dialkylsalicylic acid, naphthoic acid, dicarboxylic acid Zn, Al, Co, Cr, Fe described in JP-B-55-42752 and JP-B-59-7385 Gold Complex, copper phthalocyanine pigments sulfonated, organic boron salts, fluorine-containing quaternary ammonium salts, calixarene compounds, and the like. Naturally, it should be avoided to add a colored charge control agent to the transparent toner. However, if a very small amount is appropriately used, the transparency can be prevented and the desired charging performance can be obtained.

(Coloring agent)
The colorant is not particularly limited and may be appropriately selected from known dyes and pigments according to the purpose. For example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, ocher, yellow lead, titanium yellow, polyazo yellow, oil yellow, Hansa yellow (GR, A, RN, R), pigment yellow L, benzidine yellow (G, GR), Permanent Yellow (NCG), Vulcan Fast Yellow (5G, R), Tartrazine Lake, Quinoline Yellow Lake, Anthrazan Yellow BGL, Isoindolinone Yellow, Bengala, Lead Red, Lead Red, Cadmium Red, Cad Muum Mercury Red, Antimon Zhu, Permanent Red 4R, PA Red, Faise Red, Parachlor Ortho Nitroaniline Red, Resol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmine BS, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Risor Rubin GX, Permanent Red F5R, Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Toluidine Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake B, Rhodamine Lake Y, Alizarin Lake, Thioindigo Red B, Thioindigo Maroon, Oh Lured, Quinacridone Red, Pyrazolone Red, Polyazo Red, Chrome Vermilion, Benzidine Orange, Perinone Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkaline Blue Lake, Peacock Blue Lake, Victoria Blue Lake, Metal Free Phthalocyanine Blue, Phthalocyanine Blue, Fast Sky Blue, Indanthrene Blue (RS, BC), Indigo, Ultramarine Blue, Bitumen, Anthraquinone Blue, Fast Violet B, Methyl Violet Lake, Cobalt Purple, Manganese Purple, Dioxane Violet, Anthraquinone Violet, Chrome Green, Zinc Green, Oxidation Chrome, Pyridian, Emerald Green, Pigment Green B, Naphthol Green B, Green Gold, Ash Examples include green lake, malachite green lake, phthalocyanine green, anthraquinone green, titanium oxide, zinc white, and lithopone. These may be used individually by 1 type and may use 2 or more types together. The content of the colorant in the color toner is preferably 0.1 to 50% by mass, and more preferably 1 to 10% by mass. The content in the transparent toner is preferably 0.0 to 0.1% by mass.

  The colorant may be used as a master batch combined with a binder resin. The binder resin is not particularly limited and may be appropriately selected from known ones according to the purpose. For example, styrene or a substituted polymer thereof, a styrene copolymer, polymethyl methacrylate, Butyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, aliphatic hydrocarbon resin, Examples thereof include alicyclic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffins, and paraffins. These may be used individually by 1 type and may use 2 or more types together.

(External additive)
Examples of inorganic fine particles that can be used as external additives for transparent toners and color toners include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, iron oxide, copper oxide, and zinc oxide. , Tin oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, chromium oxide, cerium oxide, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, silicon nitride And so on. Among these inorganic fine particles, metal oxides, metal nitrides, and metal carbides are preferable. These inorganic fine particles are more preferably used in an amount of 0.01 to 5% by weight based on the toner base.

  As a means of highly controlling the fluidity of the toner, not only the control of the production conditions of the external additive, but also the crushing, sieving and the like after the production of the external additive are effective. The adhesion state is also important.

As the external additive, inorganic fine particles or hydrophobized inorganic particles can be used in combination. The average particle size of the hydrophobized primary particles is 1 to 20 nm, more preferably 6 to 15 nm (specific surface area according to the BET method). 100 to 400 m ² / g), and 30 to 150 nm, more preferably 90 to 130 nm ( ²⁰ to 100 m ² / g in specific surface area according to the BET method), More preferably, two or more types are present on the toner surface. More preferably, the small particle size inorganic fine particles are silica or titanium oxide, and both are more preferable. Silica is more preferable for the large particle size inorganic fine particles. Further, silica produced by a wet method such as a sol-gel method is more preferable. Further, it is more preferable that inorganic fine particles having a medium particle diameter of 20 to 50 nm (specific surface area by BET method of 40 to 100 m ² / g), more preferably silica, are further present on the toner surface.

  As the inorganic fine particles, known ones can be used if the conditions are satisfied. For example, silica fine particles, hydrophobic silica, fatty acid metal salts (such as zinc stearate and aluminum stearate), metal oxides (such as titania, alumina, tin oxide, and antimony oxide), fluoropolymers, and the like may be contained.

  Particularly suitable additives include hydrophobized silica, titania, titanium oxide, and alumina fine particles. Examples of the silica fine particles include HDKH2000, HDKH2000 / 4, HDKH2050EP, HVK21, HDKH1303 (manufactured by Hoechst) and R972, R974, RX200, RY200, R202, R805, and R812 (all Nippon Aerosil). Further, as titania fine particles, P-25 (made by Nippon Aerosil Co., Ltd.), STT-30, STT-65C-S (made by Titanium Industry Co., Ltd.), TAF-140 (made by Fuji Titanium Industry Co., Ltd.), MT-150W , MT-500B, MT-600B, MT-150A (manufactured by Teika). In particular, as hydrophobized titanium oxide fine particles, T-805 (manufactured by Nippon Aerosil Co., Ltd.), STT-30A, STT-65S-S (manufactured by Titanium Industry Co., Ltd.), TAF-500T, TAF-1500T (manufactured by Fuji). Titanium Industry Co., Ltd.), MT-100S, MT-100T (manufactured by Teika), IT-S (manufactured by Ishihara Sangyo) and the like.

Further, it is more preferable that the hydrophobized oxide fine particles have a particularly high degree of hydrophobization treatment.
In order to obtain hydrophobized oxide fine particles, silica fine particles, titania fine particles, and alumina fine particles, hydrophilic fine particles are treated with a silane coupling agent such as methyltrimethoxysilane, methyltriethoxysilane, or octyltrimethoxysilane. Can be obtained. In addition, silicone oil-treated oxide fine particles and inorganic fine particles obtained by treating silicone oil with heat if necessary to treat it with inorganic fine particles are also suitable.

  Examples of the silicone oil include dimethyl silicone oil, methylphenyl silicone oil, chlorophenyl silicone oil, methyl hydrogen silicone oil, alkyl modified silicone oil, fluorine modified silicone oil, polyether modified silicone oil, alcohol modified silicone oil, amino modified silicone. Oil, epoxy-modified silicone oil, epoxy-polyether-modified silicone oil, phenol-modified silicone oil, carboxyl-modified silicone oil, mercapto-modified silicone oil, acrylic, methacryl-modified silicone oil, α-methylstyrene-modified silicone oil, and the like can be used.

  In addition, polymer fine particles such as polystyrene obtained by soap-free emulsion polymerization, suspension polymerization and dispersion polymerization, methacrylic acid ester and acrylic acid ester copolymer, polycondensation system such as silicon, benzoguanamine and nylon, thermosetting resin And 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 cleaning improvers for removing the developer after transfer remaining on the photoreceptor and the primary transfer medium include soap-free fatty acid metal salts such as zinc stearate and calcium stearate, such as polymethyl methacrylate fine particles and polystyrene fine particles. Examples thereof include fine polymer particles produced by 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.

(Mixing conditions)
As a method of adding to the toner, not only dry external addition treatment using a Henschel mixer, Q mixer, etc., but also wet external addition treatment (solvent, water (containing an activator for improving wettability as required)). Adhesion is also effective.

  The external additive is mixed into the base toner. The external additive is added to the base toner by mixing and stirring the base toner and the external additive using a mixer while the external additive is crushed on the toner surface. It may be a dry mix to be coated. At this time, it is important in terms of durability that external additives such as inorganic fine particles and resin fine particles are uniformly and firmly attached to the base toner. As these addition and mixing conditions, the blade shape of the mixer, the number of rotations, the mixing time, the number of mixing, the amount of external additive, the amount of the base toner, and the surface property of the base toner (unevenness, hardness, viscoelasticity, etc.) are important. .

(Image forming method)
Hereinafter, an image forming apparatus A which is an embodiment of an image forming apparatus for carrying out an image forming method according to the present invention will be described.

(Image Forming Method 1)
FIG. 2 is a diagram illustrating the entire image forming apparatus A. First, the image forming method 1 will be described.

The image data sent to the image processing unit (referred to as “IPU”) 14 creates image signals of five colors of Y (yellow), M (magenta), C (cyan), Bk (black), and transparent.
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, respectively, and charges the photosensitive drum by the charging units 51, 52, 53, 54, and 55, respectively. An electrostatic latent image is formed on the photosensitive drums 21, 22, 23, 24, and 25. Here, for example, the first photosensitive drum 21 is set to Bk, the second photosensitive drum 22 is set to Y, the third photosensitive drum 23 is set to M, the fourth photosensitive drum 24 is set to C, and the fifth is set. The photosensitive drum 25 corresponds to transparency.

  Next, toner images of respective colors are formed on the photosensitive drums 21, 22, 23, 24, and 25 by developing units 31, 32, 33, 34, and 35 as developing attachment means. Further, the transfer paper fed by the manual paper feed unit 16 is conveyed on the transfer belt 70, and the photosensitive drums 21, 22, 23, 24, sequentially by the transfer charges 61, 62, 63, 64, 65. 25 is transferred onto a transfer sheet (recording member) and discharged from the image forming apparatus A. At this time, the transfer belt 70 is rotated counterclockwise in the image forming apparatus A shown in FIG. 2, and the transparent toner is transferred from the photosensitive member 25 to the uppermost layer of the transfer paper (lastly laminated on the transfer surface). )

  After the transfer step, the transfer paper is conveyed to the fixing unit 80, and the transferred toner image is fixed on the transfer paper by the fixing unit 80. At this time, the transfer paper is supplied to the fixing unit 80 while carrying the transparent toner on the uppermost layer, and is fixed as it is.

  After the transfer process, the toner remaining on the photosensitive drums 21, 22, 23, 24, and 25 is removed by the cleaning units 41, 42, 43, 44, and 45.

  Alternatively, the transfer sheet on which the image is formed only on one side is not ejected from the image forming apparatus A after being ejected from the fixing unit 80, and is reversed and conveyed by the recording medium reversing unit 90, and is again transferred by the paper feeding unit 17 to the transfer belt. It is good also as what is called double-sided printing provided on 70. FIG. The transfer paper provided again on the transfer belt 70 is discharged from the image forming apparatus A after image formation is performed in the same manner as in the above-described image forming method on one side where no image is formed.

  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.

(Image forming method 2)
FIG. 3 is a diagram illustrating the entire image forming apparatus B. Differences between the image forming method 2 and the above-described image forming method 1 will be described.

  In the image forming apparatus B shown in FIG. 3, a photosensitive member is placed on a transfer belt 70 in the form of an intermediate transfer belt (primary transfer means) by transfer charges 61, 62, 63, 64, 65 in the form of transfer rollers. It has a so-called intermediate transfer process in which the toner images on the drums 21, 22, 23, 24, and 25 are transferred (primary transfer).

  At this time, the transfer belt 70 as an intermediate transfer belt is rotated clockwise in the image forming apparatus B shown in FIG. 3, and the transparent toner is transferred from the photosensitive member 25 to the lowermost layer of the transfer belt 70 (transfer). First laminated to the surface).

After the intermediate transfer process is completed, the transferred toner image is supplied to the secondary transfer means 66 composed of a pair of rollers while being held on the transfer belt 70, and is transferred onto the transfer paper (recording member). Next is transferred. At this time, the transfer paper is secondarily transferred so that the uppermost layer carries the transparent toner.
Thereafter, the transfer paper is conveyed to the fixing unit 80, and the transferred toner image is fixed on the transfer paper by the fixing unit 80. At this time, the transfer paper is supplied to the fixing unit 80 while carrying the transparent toner on the uppermost layer, and is fixed as it is.
In addition, since it overlaps with the image forming method 1 except the form demonstrated above, description is abbreviate | omitted.

EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated further more concretely, this invention is not limited to these. “Part” is based on weight.
Carrier and toner were produced under the following conditions.

(Method for manufacturing carrier 1)
[Carrier coating layer formulation]
-Silicone resin solution (solid content 23 wt%): 432.2 parts by weight (SR2410: Toray Dow Corning Silicone)
Aminosilane (solid content: 100% by weight): 0.66 parts by weight (SH6020: manufactured by Toray Dow Corning Silicone)
Conductive fine particles EC-500 [manufactured by Titanium Industry Co., Ltd.]: 145 parts by weight (manufactured by Titanium Industry Co., Ltd., particle size: 0.43 μm, true specific gravity: 4.6, powder specific resistance: 3, substrate: titanium oxide (powder Conductive treated fine particles with body resistivity 9)
-Toluene: 300 parts by weight

The material of the coating layer formulation was dispersed with a homomixer for 10 minutes to obtain a silicon resin coating film forming solution. Using 5000 parts by weight of a sintered ferrite powder (true specific gravity 5.5) having an average particle diameter of 35 μm as a core material, the coating film forming solution is coated on the core material surface so that the film thickness of the coating layer is 0.35 μm. It was applied and dried at a coater internal temperature of 40 ° C. using a Spira coater (Okada Seiko Co., Ltd.). The obtained carrier was fired in an electric furnace at 200 ° C. for 1 hour. After cooling, the ferrite powder bulk was crushed using a sieve having an aperture of 63 μm to obtain [Carrier 1] having a static resistance of 12.9 [Log (Ω · cm)] and a magnetization of 68 Am ² / kg.

  In addition, about the average particle diameter measurement of a carrier core material, what was performed by using the SRA type of a micro track particle size analyzer (Nikkiso Co., Ltd.) and the range setting of 0.7 micrometer or more and 125 micrometers or less was used. The average particle size is D50.

Magnetization measurement was performed by the following method using VSM-P7-15 manufactured by Toei Industry Co., Ltd. About 0.15 g of the sample was weighed, the sample was filled in a cell having an inner diameter of 2.4 mmφ and a height of 8.5 mm, and measured under a magnetic field of 1000 oersted (Oe). 1000 oersted (Oe) corresponds to 1000 (10 ³ / 4π · A / m).

(Method for manufacturing carrier 2)
Volume specific resistance: 13.1 [Log (Ω · cm)], magnetization: The same as in the carrier 1 manufacturing method, except that the coating layer formulation is changed to an acrylic resin-based and silicon resin-based mixed system described below. [Carrier 2] of 68 Am ² / kg was obtained.

[Carrier coating layer formulation]
-Acrylic resin solution (solid content 50 wt%): 34.2 parts by weight-Guanamine solution (solid content 70 wt%): 9.7 parts by weight-Acidic catalyst (solid content 40 wt%): 0.19 parts by weight- Silicone resin solution (solid content 20% by weight): 432.2 parts by weight (SR2410: manufactured by Toray Dow Corning Silicone)
Aminosilane (solid content: 100% by weight): 3.42 parts by weight (SH6020: manufactured by Toray Dow Corning Silicone)
-Conductive fine particles EC-500 [made by Titanium Industry Co., Ltd.] 145 parts by weight-Toluene: 500 parts by weight

(Method for manufacturing carrier 3)
The specific volume resistivity: 13.1 [Log (Ω · cm)], magnetization: except for changing the prescription ratio between the acrylic resin type and the silicon resin type as described below for the coating layer, It was obtained [carrier 3] of 68 Am ² / kg.

[Carrier coating layer formulation]
Acrylic resin solution (solid content 50% by weight): 17.1 parts by weight Guanamine solution (solid content 70% by weight): 4.85 parts by weight Acidic catalyst (solids content 40% by weight): 0.10 parts by weight Silicone resin solution (solid content 20% by weight): 216.2 parts by weight (SR2410: manufactured by Toray Dow Corning Silicone)
Aminosilane (solid content: 100% by weight): 1.68 parts by weight (SH6020: manufactured by Toray Dow Corning Silicone)
-Conductive fine particles EC-500 [manufactured by Titanium Industry Co., Ltd.]: 145 parts by weight-Toluene: 600 parts by weight

(Method for manufacturing carrier 4)
Volume specific resistance: 13.7, in the same manner as in Example 1, except that a carrier core material having a weight average particle diameter of 18 μm (true specific gravity of 5.7) is used and the coating layer formulation is changed to the one described below. [Carrier 4] having [Log (Ω · cm)] and magnetization: 66 Am ² / kg was obtained.

[Carrier coating layer formulation]
-Acrylic resin solution (solid content 50 wt%): 68.4 parts by weight-Guanamin solution (solid content 70 wt%): 19.4 parts by weight-Acidic catalyst (solid content 40 wt%): 0.38 parts by weight- Silicone resin solution (solid content 20% by weight): 864.4 parts by weight (SR2410: manufactured by Toray Dow Corning Silicone)
Aminosilane (solid content: 100% by weight): 0.46 parts by weight (SH6020: Toray Dow Corning Silicone)
-Conductive fine particles EC-500 [manufactured by Titanium Industry Co., Ltd.]: 275 parts by weight-Toluene: 800 parts by weight

(Method for manufacturing carrier 5)
Volume specific resistance: 12. As in Example 1, except that a carrier core material having a weight average particle diameter of 71 μm (true specific gravity 5.3) is used and the coating layer formulation is changed to the one described below. 5 [Log (Ω · cm)] and magnetization: 69 Am ² / kg [Carrier 5] were obtained.

[Carrier coating layer formulation]
-Acrylic resin solution (solid content 50 wt%): 34.2 parts by weight-Guanamine solution (solid content 70 wt%): 9.7 parts by weight-Acidic catalyst (solid content 40 wt%): 0.19 parts by weight- Silicone resin solution (solid content 20% by weight): 292.9 parts by weight (SR2410: manufactured by Toray Dow Corning Silicone)
Aminosilane (solid content: 100% by weight): 0.42 parts by weight (SH6020: Toray Dow Corning Silicone)
-Conductive fine particles EC-500 [manufactured by Titanium Industry Co., Ltd.]: 85 parts by weight-800 parts by weight of toluene

(Method for manufacturing carrier 6)
The material of the following coating layer formulation was dispersed with a homomixer for 10 minutes to obtain a silicon resin coating film forming solution for a carrier coating layer.
Using 5000 parts by weight of a sintered ferrite powder (true specific gravity 5.5) having an average particle diameter of 35 μm as a carrier core material, the coating film forming solution is coated on the core material surface so that the film thickness of the coating layer is 0.35 μm. Then, it was applied and dried at a coater temperature of 40 ° C. using a Spira coater (Okada Seiko Co., Ltd.). The obtained carrier was fired in an electric furnace at 200 ° C. for 1 hour. After cooling, the ferrite powder bulk was crushed using a sieve having an aperture of 63 μm to obtain [Carrier 6] having a volume resistivity of 12.9 [Log (Ω · cm)] and a magnetization of 68 Am ² / kg.

[Carrier coating layer formulation]
-Silicone resin solution (solid content 23 wt%): 432.2 parts by weight (SR2410: Toray Dow Corning Silicone)
Aminosilane (solid content: 100% by weight): 0.66 parts by weight (SH6020: manufactured by Toray Dow Corning Silicone)
Carbon black MA100R (manufactured by Mitsubishi Chemical): 20 parts by weight Toluene: 300 parts by weight

(Method for manufacturing carrier 7)
[Carrier 7] was obtained in the same manner as in the carrier 1 production method except that the conductive fine particles were changed from EC-500 to EC-700 in the carrier 1 production method.
That is, the material of the following coating layer formulation was dispersed with a homomixer for 10 minutes to obtain a silicon resin coating film forming solution. Using 5000 parts by weight of a sintered ferrite powder (true specific gravity 5.5) having an average particle diameter of 35 μm as a core material, the coating film forming solution is coated on the core material surface so that the film thickness of the coating layer is 0.35 μm. It was applied and dried at a coater internal temperature of 40 ° C. using a Spira coater (Okada Seiko Co., Ltd.). The obtained carrier was fired in an electric furnace at 200 ° C. for 1 hour. After cooling, the ferrite powder bulk was pulverized using a sieve having an aperture of 63 μm to obtain [Carrier 7] having a volume resistivity of 12.9 [Log (Ω · cm)] and a magnetization of 68 Am ² / kg.

[Carrier coating layer formulation]
-Silicone resin solution (solid content 23 wt%): 432.2 parts by weight (SR2410: Toray Dow Corning Silicone)
Aminosilane (solid content: 100% by weight): 0.66 parts by weight (SH6020: manufactured by Toray Dow Corning Silicone)
Conductive fine particles EC-700 [manufactured by Titanium Industry Co., Ltd.]: 145 parts by weight (manufactured by Titanium Industry Co., Ltd., particle size: 0.41 μm, true specific gravity: 4.3, powder specific resistance: 4, substrate: alumina (powder Conductive treated fine particles with specific resistance 12)
-Toluene: 300 parts by weight

(Manufacturing method of carrier 8)
In the manufacturing method of the carrier 2, the specific volume resistivity is 14.1 [Log] except that 35 μm high sintered magnetization (true specific gravity 5.5) is used and the magnetization is changed to 93 Am ² / kg. (Ω · cm)] [Carrier 8] was obtained.

(Method for manufacturing carrier 9)
Volume specific resistance: 16.1 [Log (Ω · cm)], magnetization: 68 Am, except that the coating layer formulation was changed to a mixed system of acrylic resin and silicon resin as described below. ² / kg of [Carrier 9] was obtained.

[Carrier coating layer formulation]
-Acrylic resin solution (solid content 50 wt%): 34.2 parts by weight-Guanamine solution (solid content 70 wt%): 9.7 parts by weight-Acidic catalyst (solid content 40 wt%): 0.19 parts by weight- Silicone resin solution (solid content 20% by weight): 432.2 parts by weight (SR2410: manufactured by Toray Dow Corning Silicone)
Aminosilane (solid content: 100% by weight): 3.42 parts by weight (SH6020: Toray Dow Corning Silicone)
Inorganic oxide fine particles B: 97 parts by weight (aluminum oxide, particle size 0.37 μm, true specific gravity 3.9)
-Toluene: 500 parts by weight

(Manufacturing method of carrier 10)

The volume resistivity of 13.9 [Log] is the same as in the carrier 2 manufacturing method except that 36 μm low-magnetization sintered ferrite (true specific gravity 5.4) is used and the magnetization is changed to 35 Am ² / kg. (Ω · cm)] [Carrier 10] was obtained.

(Manufacturing method of carrier 11)
[Carrier 1] Volume specific resistance: 8.9 [Log (Ω · cm)], magnetization: 68 Am ² / kg [Carrier] 11] was obtained.

(Synthesis of crystalline polyester resin 1)
Into a 5-liter four-necked flask equipped with a nitrogen inlet tube, a dehydrating tube, a stirrer and a thermocouple, 2,300 g of 1,10-decanediol, 2530 g of 1,8-octanediol and 4.9 g of hydroquinone were added at 180 ° C. After making it react for 10 hours, it heated up at 200 degreeC, made to react for 3 hours, and also was made to react at 8.3 kPa for 2 hours, and the crystalline polyester resin 1 was obtained.

(Method for producing transparent toner 1)
[Toner raw materials]
Non-crystalline polyester resin 80 parts by weight (Tg 67.5 ° C., Mw 18700, Mn 4900, acid value 6.6 mg KOH / g)
Crystalline polyester 1 20 parts by weight (Tg 71 ° C., Mw 11000, Mn 3200)
Carnauba wax (Serarica NODA / Carnauba wax No. 1) 5 parts by weight

  The above toner raw materials are premixed using a Henschel mixer (Mitsui Miike Chemical Co., Ltd., FM20B), and then heated at a temperature of 100 to 130 ° C. with a biaxial kneader (Ikegai Co., Ltd., PCM-30). Was melted and kneaded. The obtained kneaded product was cooled to room temperature and then coarsely pulverized to 200 to 300 μm with a hammer mill. Next, after finely pulverizing using a supersonic jet pulverizer, Labo Jet (manufactured by Nippon Pneumatic Industry Co., Ltd.), adjusting the pulverization air pressure appropriately so that the weight average particle diameter becomes 5.2 ± 0.3 μm. The weight average particle diameter is 6.0 ± 0.2 μm and the ratio of the weight average particle diameter / number average particle diameter is 1.20 or less with an airflow classifier (manufactured by Nippon Pneumatic Industry Co., Ltd., MDS-I). In this way, classification was performed while appropriately adjusting the louver opening to obtain toner base particles. Next, 1.0 part by weight of an additive (HDK-2000, manufactured by Clariant Co., Ltd.) was stirred and mixed with 100 parts by mass of the toner base particles with a Henschel mixer to produce a transparent toner 1.

(Production example of transparent toner two-component developer)
95% by weight of each carrier and 5% by weight of the transparent toner were uniformly mixed and charged at 48 rpm for 5 minutes using a tumbler mixer (made by Willy et Bacofen (WAB)), and each of the two components was developed with transparent toner. An agent was prepared.

(Method for producing cyan master batch 1)
C. I. Pigment Blue 15: 350 parts, amorphous polyester resin (manufactured by Sanyo Chemical Industries, RS801, 50 parts), and further 30 parts of water are added and mixed with a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.). After kneading at 160 ° C. for 50 minutes, the mixture was cooled and rolled, and pulverized with a pulverizer to obtain cyan master batch 1.

(Synthesis of crystalline polyester resin 1)
Into a 5-liter four-necked flask equipped with a nitrogen inlet tube, a dehydrating tube, a stirrer and a thermocouple, 2,300 g of 1,10-decanediol, 2530 g of 1,8-octanediol and 4.9 g of hydroquinone were added at 180 ° C. After making it react for 10 hours, it heated up at 200 degreeC, made to react for 3 hours, and also was made to react at 8.3 kPa for 2 hours, and the crystalline polyester resin 1 was obtained.

(Example of production of cyan toner 1)
[Toner raw materials]
Non-crystalline polyester resin 72 parts by weight (Tg 63 ° C., Mw 113000, Mn 3700, acid value 6.6 mg KOH / g)
Crystalline polyester 1 20 parts by weight (Tg 71 ° C., Mw 11000, Mn 3200)
Carnauba wax (Serarica NODA / Carnauba wax No. 1) 4 parts by weight Cyan masterbatch 1 16 parts by weight

  Cyan toner 1 was produced in the same manner as transparent toner 1 except that the above toner raw materials were used.

(Cyan toner two-component developer production example)
Cyan toner 2 component developer 5% by weight of cyan toner 1 and 95% by weight of coated ferrite carrier are uniformly mixed and charged for 5 minutes at 48 rpm using a Turbler mixer (made by Willy et Bacofen (WAB)). Was made.

The evaluation methods and conditions in Examples and Comparative Examples are shown below. The evaluation results are shown in Table 1 below.
<Carrier adhesion>
Set a transparent toner developer on the black unit of a commercially available digital full-color printer (Imagio NeoC455 manufactured by Ricoh), set the charging potential to DC 740V and the developing bias 600V (fix the background potential to 140V), and develop the dot-forming halftone The number of carriers adhering to the surface of the photosensitive member was counted by five visual field observations with a magnifying glass, and the average number of adhering carriers per 100 cm 2 was taken as the edge carrier adhering amount. The evaluation was as follows: ◎: 20 or less, ◯: 21 to 60, △: 61 to 80, ×: 81 or more, 合格: passed and △: rejected. Since the transparent toner is white in an unfixed state, it can be easily observed.

<Glossiness>
After running a 300,000 image chart with a 50% image area in monochrome mode, develop a transparent toner solid image on cyan solid, output the image on 6000 paper manufactured by Ricoh, and make its glossiness by Nippon Denshoku Industries Co., Ltd. Glossmeter VGS-1D was used to evaluate 10 images with a gloss of 60 degrees, average gloss was 50 or more, ◯, less than 50, 30 or more, △, 30 or less 20 or more, and less than 20 ×, ◎ It was determined to be acceptable and △ × was regarded as unacceptable.

Example 1
An image was formed using carrier 1, transparent toner 1 and cyan toner 1 to obtain a fixed image. The number of carrier deposits on the photoreceptor was 8, and the gloss of the transparent toner was 62.

Example 2
An image was formed using carrier 2, transparent toner 1 and cyan toner 1, and a fixed image was obtained. The carrier adhesion on the photosensitive member was 15, and the gloss of the transparent toner was 65.

Example 3
An image was formed using carrier 3, transparent toner 1 and cyan toner 1, and a fixed image was obtained. The carrier adhesion on the photoreceptor was 14, and the gloss of the transparent toner was 64.

Example 4
An image was formed using carrier 4, transparent toner 1 and cyan toner 1 to obtain a fixed image. The carrier adhesion on the photosensitive member was 22, and the gloss of the transparent toner was 45.

Example 5
An image was formed using carrier 5, transparent toner 1 and cyan toner 1 to obtain a fixed image. The number of carrier deposits on the photosensitive member was 7, and the gloss of the transparent toner was 52.

Example 6
An image was formed using carrier 6, transparent toner 1 and cyan toner 1, and a fixed image was obtained. The carrier adhesion on the photosensitive member was 10, and the gloss of the transparent toner was 43.

Example 7
An image was formed using carrier 7, transparent toner 1 and cyan toner 1, and a fixed image was obtained. The carrier adhesion on the photosensitive member was 12, and the gloss of the transparent toner was 43.

Comparative Example 1
An image was formed using carrier 8, transparent toner 1 and cyan toner 1 to obtain a fixed image. The number of carriers deposited on the photoreceptor was 45, and the gloss of the transparent toner was 48.

Comparative Example 2
An image was formed using carrier 9, transparent toner 1 and cyan toner 1, and a fixed image was obtained. The number of carriers deposited on the photoreceptor was 68, and the gloss of the transparent toner was 25.

Example 8
An image was formed using carrier 10, transparent toner 1 and cyan toner 1, and a fixed image was obtained. The carrier adhesion on the photoconductor was 25, and the gloss of the transparent toner was 40.

Comparative Example 3
An image was formed using carrier 11, transparent toner 1 and cyan toner 1, and a fixed image was obtained. The carrier adhesion on the photoreceptor was 110, and the gloss of the transparent toner was 26.

[Evaluation results]
From Table 1, in Examples 1 to 8 which are within the scope of the present invention, there was little carrier adhesion and high gloss was obtained because of good image density. On the other hand, the toner of the comparative example has a large adhesion amount or low image density and low gloss.
As described above, it is possible to provide a two-component developer and an image forming method capable of obtaining an image having uniform gloss without causing carrier adhesion by using the developer shown in the examples.

  Although the embodiments of the present invention have been specifically described above, the present invention is not limited to these embodiments, and these embodiments of the present invention depart from the spirit and scope of the present invention. And can be changed or modified.

(About Figure 1)
1 Cell 2a Electrode 2b Electrode 3 Carrier (FIGS. 2 and 3)
14 Image processing unit (IPU)
15 Writing unit 21 Black (Bk) toner, developer photosensitive drum 22 Yellow (Y) toner, developer photosensitive drum 23 Magenta (M) toner, developer photosensitive drum 24 Cyan (C) toner, development Photosensitive drum for developer 25 Transparent toner, photosensitive drum for developer 31 Black (Bk) toner, developing means for developer 32 Yellow (Y) toner, developing means for developer 33 Magenta (M) toner, developing for developer 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 means 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 and developer transfer means 65 Transparent toner and developer transfer means 70 Transfer belt 80 Fixing unit 90 Recording medium reversing means

JP-A-7-72696 Japanese Patent Application Laid-Open No. 2000-131884 JP 2004-151266 A Japanese Patent Laid-Open No. 56-126843 JP-A 62-45984 JP-A-8-286429

Claims (8)

A transparent toner having a binder resin and a release agent;
A two-component developer comprising an electrophotographic carrier used for developing the transparent toner,
The electrophotographic carrier has a core material and a coating layer that covers the core material, has a volume resistivity of 10 (log Ω · cm) to 14 (log Ω · cm), and an applied magnetic field of 1000 A two-component developer, wherein a magnetic moment at (10 ³ / 4π · A / m) is 35 (Am ² / kg) or more and 90 (Am ² / kg) or less.   2. The two-component developer according to claim 1, wherein the binder resin of the transparent toner is made of a thermoplastic resin containing a crystalline polyester resin.   3. The two-component developer according to claim 1, wherein the electrophotographic carrier has a volume average particle diameter of 20 μm to 65 μm. The coating layer contains a binder resin,
The two-component developer according to any one of claims 1 to 3, wherein the binder resin of the coating layer contains a silicon resin. The coating layer contains a binder resin,
The two-component developer according to any one of claims 1 to 4, wherein the binder resin of the coating layer is a mixed system of an acrylic resin and a silicon resin.   6. The two-component developer according to claim 1, wherein the transparent toner is made by a dissolution suspension method.   6. The transparent toner according to claim 1, wherein the transparent toner is obtained by melt-kneading a raw material containing a binder resin and a release agent to obtain a melt-kneaded product, and pulverizing and classifying the melt-kneaded product. The two-component developer according to any one of the above. An electrostatic latent image forming step of forming an electrostatic latent image on the image carrier;
A developing step of developing the electrostatic latent image with a developer to form a visible image;
A transfer step of transferring the visible image to a recording member;
Fixing the visible image on the recording member to the recording member,
The developer includes one or more color toner developers including a color toner and an electrophotographic carrier, and a two-component developer including the transparent toner according to any one of claims 1 to 7. Become
The image forming method, wherein, in the transferring step, the transparent toner is transferred so as to be positioned on an uppermost layer on the recording member.

Images