JP2005148179A - Method for manufacturing electrostatic latent image developing carrier, and electrostatic latent image developing carrier - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an electrostatic latent image developing carrier by which the electric resistance of a carrier coating layer can be suppressed low, an effect to prevent an edge effect and carrier deposition is imparted and deterioration in color characteristics such as turbidity of colors is prevented, and to provide a carrier manufactured by the method. <P>SOLUTION: The method for manufacturing an electrostatic latent image developing carrier includes a step of coating the surface of a core material comprising a magnetic material with a silicone resin having conductive carbon dispersed therein; and a step of mixing/stirring the carrier having the silicone resin coating layer with a yellow toner and then sucking/removing the yellow toner to remove conductive carbon depositing on the surface of the silicone resin coating layer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for producing a carrier for developing an electrostatic latent image and the carrier.

  As a carrier used for an electrostatic latent image developer, a carrier core material surface made of a magnetic material is coated with a silicone resin or the like. Since such a resin-coated carrier has a surface covered with a low surface energy substance, it is difficult for the toner to become spent during development (the toner adheres to the carrier), resulting in a stable charge amount and a developer. There is an advantage that it is possible to extend the service life. On the other hand, since the carrier is insulated with the resin coating and does not function as a developing electrode, there is a drawback that an edge effect is likely to occur particularly in a solid image portion. In addition, since the counter charge at the time of toner removal becomes excessive, carrier adhesion to non-image portions due to electrostatic development is likely to occur.

In order to solve this problem, for example, a resin-coated carrier in which conductive carbon is dispersed as a conductive agent in a carrier coating layer has been proposed (for example, see Patent Document 1).
However, when such a carrier is used, as a developer, a part of the conductive carbon containing resin floating in the atmosphere adheres to the surface of the coating layer. The adhering carbon is detached from the surface of the carrier coating layer due to the collision or the like, and adheres to the toner particles or is developed as it is. This phenomenon does not cause much problem when forming a copy image such as black characters using black toner, but it appears remarkably as a problem of color turbidity in a developer combined with color toner, particularly yellow toner.

JP-A-56-75659

  The present invention has been made in view of the above problems, and its problem is to suppress the electrical resistance of the carrier coating layer, to provide an edge effect and an action to prevent carrier adhesion, and to deteriorate color characteristics such as color turbidity. And a method for producing a carrier for an electrostatic latent image developer, and the carrier.

In order to solve the above problems, the present invention is characterized by the following.
1. The present invention is a method for producing a carrier for developing an electrostatic latent image, wherein a surface of a core material made of a magnetic material is coated with a silicone resin in which conductive carbon is dispersed, and a silicone resin coating layer is formed. A carrier for developing an electrostatic latent image, the method comprising: mixing and stirring the carrier together with the yellow toner, and then sucking and removing the yellow toner to remove the conductive carbon adhering to the surface of the silicone resin coating layer. .

2. As the yellow toner to be mixed with the carrier, fine powder or coarse powder toner generated during toner production is used.

3. The step of removing the conductive carbon adhering to the surface of the silicone resin coating layer is characterized in that the carrier on which the silicone resin coating layer is formed is stirred alone prior to mixing and stirring with the yellow toner.
4). Stirring of the carrier alone on which the silicone resin coating layer is formed is performed using a developing device having a rotatable cylindrical body having a magnet held therein at least.

5). The method for producing a carrier for developing an electrostatic latent image has a classification step after a step of coating a surface of a core material made of the magnetic material with a silicone resin in which conductive carbon is dispersed.
6). The classification step is performed using an ultrasonic vibration sieve.

7). The present invention also relates to a carrier for developing an electrostatic latent image, wherein a coating layer of a silicone resin in which conductive carbon is dispersed is formed on the surface of a core material made of a magnetic material. Is a carrier for developing an electrostatic latent image produced by any one of the above-described methods for producing a carrier for developing an electrostatic latent image, and the carrier core has a weight average particle diameter of 22 to 40 μm, and the electric resistance of the carrier has an applied voltage of 250 V. The carrier for electrostatic latent image development is 10 ¹⁰ to 10 ¹⁶ Ω · cm at / cm and the silicone resin coating layer thickness is 0.3 to 1.5 μm.
8). The carrier for developing an electrostatic latent image is characterized in that the proportion of the total particle diameter of the carrier having a particle size of 12 μm or less is 0.5% by number or less.

9. The present invention also provides a developer for developing an electrostatic latent image formed on a latent image carrier, which is a two-component development comprising the electrostatic latent image developing carrier described above and a toner. It is an agent.

10. The present invention also relates to a developing device for developing and developing an electrostatic latent image on a latent image carrier by carrying and transporting the developer by the developer carrier and forming an electric field at a position facing the latent image carrier. The developer is used.

11. Furthermore, the present invention includes at least a latent image carrier that carries a latent image, and a developing unit that supplies toner to the electrostatic latent image formed on the surface of the latent image carrier to visualize the latent image. The process cartridge is supported by the image forming apparatus and is detachably formed on the main body of the image forming apparatus. The process cartridge mounts the developing device as the developing means.
12 The present invention also provides a latent image carrier for carrying a latent image, a charging means for uniformly charging the surface of the latent image carrier, and exposing the surface of the charged latent image carrier based on image data. An exposure means for writing an electrostatic latent image, a developing means for supplying toner to the electrostatic latent image formed on the surface of the latent image carrier to make it visible, and a visible image on the surface of the latent image carrier In the image forming apparatus including a transfer unit that transfers the image to the transfer body and a fixing unit that fixes the visible image on the transfer body, the developing device is mounted as the developing unit.

  According to the present invention, there is provided a method for producing a carrier for developing an electrostatic latent image, which suppresses the electrical resistance of the carrier coating layer, has an edge effect and a carrier adhesion prevention function, and does not deteriorate color characteristics such as color turbidity, and the carrier. It became possible to do. In addition, a developing device using a developer including the carrier for developing an electrostatic latent image and an image forming apparatus equipped with the developing device can provide an image free from background stains, excellent in image quality, and free from color stains. Can do.

Hereinafter, embodiments of the present invention will be described.
A conventionally well-known thing can be used as a carrier core material which can be used by this invention. Examples thereof include ferromagnetic materials such as iron and cobalt, magnetite, hematite, Li-based ferrite, Mn—Zn-based ferrite, Cu—Zn-based ferrite, Ni—Zn ferrite, and Ba ferrite.
The weight average particle diameter of the carrier core material is preferably 22 μm or more and 40 μm or less. By setting the weight average particle diameter to 40 μm or less, it is excellent in solid uniformity and dot reproducibility, and a high-definition image can be obtained. On the other hand, if the thickness is less than 22 μm, the magnetic binding force with the developing sleeve of the developing device becomes small, which causes a carrier adhesion. The weight average particle diameter of the carrier core material is measured using a Microtrac particle size analyzer (model HRA9320-X100; manufactured by Honewell).

  As the silicone resin for coating the carrier core material, conventionally known silicone resins can be used, and examples thereof include straight silicones composed of organosiloxane bonds and silicone resins modified with alkyd, polyester, epoxy, urethane and the like. Examples of straight silicone resins include KR271, KR272, KR282, KR252, KR255, KR152 (manufactured by Shin-Etsu Chemical Co., Ltd.), SR2400, SR2406 (manufactured by Toray Dow Corning Silicone). Examples of the modified silicone include epoxy-modified silicone, acrylic-modified silicone, phenol-modified silicone, urethane-modified silicone, polyester-modified silicone, and alkyd-modified silicone. Examples of modified silicone include epoxy-modified: ES-1001N, acrylic Modification: KR-5208, polyester modification: KR-5203, alkyd modification: KR-206, urethane modification: KR-305 (manufactured by Shin-Etsu Chemical Co., Ltd.), epoxy modification: SR-2115, alkyd modification: SR2110 (Toray Dow) Corning Silicone).

  As the conductive carbon dispersed in the silicone resin, any carbon black having conductivity can be used. For example, furnace black (for example, Black Pearls 2000, Carbolac1 manufactured by Cabot Corporation; Ketjen Black EC-DJ manufactured by Lion Akzo Corporation) 500, ketjen black EC-DJ 600, etc.), and acetylene black (commercially available products are Denka black granules and Denka black powders manufactured by Denki Kagaku Kogyo Co., Ltd .; Anacarbon etc. manufactured by Postman). The average particle size of the conductive carbon is preferably 0.1 to 0.3 μm.

  In addition to this, a charge control agent can be used as an additive in the coating layer of the carrier core material. In the case of using a silicone resin for the coating layer, it is particularly effective to add an aminosilane coupling agent, and 0.1 to 10 parts by weight, preferably 0.2 to 5 parts by weight is added to 100 parts by weight of the silicone resin. Good.

As a method for forming the resin coating layer on the surface of the carrier core material, a known method such as a spray drying method, a dipping method, or a powder coating method can be used.
The layer thickness of the silicone resin coating layer is preferably 0.3 to 1.5 μm. By setting the layer thickness to 0.3 μm or more, it is possible to suppress spent by developing toner. On the other hand, when the layer thickness exceeds 1.5 μm, the carrier chargeability is deteriorated, and background stains are likely to occur on the image.
The thickness of the carrier coating layer can be measured by various methods. For example, when the specific gravity of each of the used carrier core material and coating layer material is known, the true specific gravity of the carrier can be accurately measured.

The electric resistance of the carrier thus obtained is preferably in the range of 10 ¹⁰ to 10 ¹⁶ Ω · cm when the applied voltage is 250 V / cm. When the electric resistance is less than 10 ¹⁰ Ω · cm, charge is easily injected from the surface of the electrostatic latent image carrier to the carrier particles, and carrier adhesion is likely to occur. If it exceeds 10 ¹⁶ Ω · cm, it will be difficult to obtain a high-density image.
The electrical resistance of the carrier is a value obtained from a current value and an applied voltage when a carrier is filled between two parallel electrodes and a potential difference is provided between the electrodes. Specifically, a container having electrodes arranged in parallel with an interval of 2 mm is filled with a carrier, and a direct current resistance at a potential difference of 250 V between the two electrodes is measured with a 4329A High Resistance Meter manufactured by Yokogawa Hewlett-Packard Co., Ltd.

  Further, the ratio of the total particle diameter of the carrier having a particle size of 12 μm or less to 0.5% by number or less is preferable. Thereby, carrier adhesion can further be suppressed.

According to the method for producing a carrier for developing an electrostatic latent image of the present invention, the carrier on which the silicone resin coating layer is formed as described above is mixed and stirred together with the yellow toner, and then the yellow toner is sucked and removed. A step of removing conductive carbon adhering to the surface of the coating layer; For mixing and stirring of the carrier and the yellow toner, a conventionally known stirring and mixing device such as a turbula shaker mixer, a nauter mixer, a V-type mixer, or a W corn type mixer can be used. It is preferable to use a mixer. As a result, the conductive carbon adhering to the surface of the silicone resin coating layer is transferred to the yellow toner, and then sucked and removed together with the yellow toner, so that it is removed from the carrier surface.
The electrostatic latent image developing carrier of the present invention produced as described above does not cause deterioration of color characteristics such as color turbidity even when used as a developer combined with yellow toner.

  As the yellow toner mixed with the carrier, fine powder or coarse powder toner generated at the time of toner production can be used. The fine powder / coarse powder toner is removed from the product by classification at the time of toner production, and by using this, it is possible to effectively use resources.

  Also, prior to mixing and stirring the carrier and yellow toner, it is effective to perform an operation of stirring the carrier on which the silicone resin coating layer is formed alone. By stirring the carrier alone, the carriers collide with each other, and the conductive carbon adhering to the surface of the silicone resin coating layer can be detached or easily separated. The removal efficiency of conductive carbon can be improved by mixing and stirring.

  The carrier alone may be stirred using the same device as that used for mixing and stirring with the yellow toner, but at least using a developing device having a rotatable cylindrical body holding a magnet inside. Is even better. By being influenced by the magnetic field, the carriers are efficiently and uniformly stirred, and the removal efficiency of the conductive carbon adhering to the surface of the coating layer can be further increased.

Furthermore, adding a classification step after the step of coating the surface of the core material with the silicone resin is also effective for removing conductive carbon adhering to the surface of the coating layer. The carrier on which the silicone resin coating layer is formed can be classified using a wet classification method, a sieving classification method, or an airflow classification method. Among these, it is more effective to use an ultrasonic vibration type sieve. By this classification treatment, a part of the conductive carbon adhering to the silicone coating layer surface can be removed, and the removal efficiency can be improved by the subsequent step of removing the conductive carbon.

  Next, examples of constituent materials and manufacturing methods of toners preferably used in the present invention will be shown. The toner used in the present invention is not limited to this.

(Modified polyester)
The toner according to the present invention contains a modified polyester (i) as a binder resin. The modified polyester (i) refers to a state in which a bonding group other than an ester bond is present in the polyester resin, or resin components having different configurations are bonded to the polyester resin by a covalent bond, an ionic bond, or the like. Specifically, the polyester terminal is modified by introducing a functional group such as a carboxylic acid group or an isocyanate group that reacts with a hydroxyl group into the polyester terminal and further reacting with an active hydrogen-containing compound.

  Examples of the modified polyester (i) include urea-modified polyester obtained by a reaction between a polyester prepolymer (A) having an isocyanate group and amines (B). As the polyester prepolymer (A) having an isocyanate group, a polyester having a polycondensate of a polyhydric alcohol (PO) and a polyvalent carboxylic acid (PC) and having an active hydrogen group is further added to a polyvalent isocyanate compound (PIC). And those reacted with. Examples of the active hydrogen group possessed by the polyester include a hydroxyl group (alcoholic hydroxyl group and phenolic hydroxyl group), an amino group, a carboxyl group, a mercapto group, and the like. Among these, an alcoholic hydroxyl group is preferable.

The urea-modified polyester is produced as follows.
Examples of the polyhydric alcohol compound (PO) include dihydric alcohol (DIO) and trihydric or higher polyhydric alcohol (TO). (DIO) alone or a mixture of (DIO) and a small amount of (TO) preferable. Examples of the dihydric alcohol (DIO) include alkylene glycol (ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, etc.); alkylene ether glycol (diethylene glycol) , Triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, etc.); alicyclic diols (1,4-cyclohexanedimethanol, hydrogenated bisphenol A, etc.); bisphenols (bisphenol A, bisphenol) F, bisphenol S, etc.); alkylene oxide (ethylene oxide, propylene oxide, butylene oxide, etc.) adduct of the above alicyclic diol; Alkylene oxide bisphenol (ethylene oxide, propylene oxide, butylene oxide, etc.), etc. adducts. Among them, preferred are alkylene glycols having 2 to 12 carbon atoms and alkylene oxide adducts of bisphenols, and particularly preferred are alkylene oxide adducts of bisphenols and alkylene glycols having 2 to 12 carbon atoms. It is a combined use. The trihydric or higher polyhydric alcohol (TO) includes 3 to 8 or higher polyhydric aliphatic alcohols (glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, etc.); trihydric or higher phenols (Trisphenol PA, phenol novolak, cresol novolak, etc.); and alkylene oxide adducts of the above trivalent or higher polyphenols.

  Examples of the polyvalent carboxylic acid (PC) include divalent carboxylic acid (DIC) and trivalent or higher polyvalent carboxylic acid (TC). (DIC) alone and (DIC) with a small amount of (TC) Mixtures are preferred. Divalent carboxylic acids (DIC) include alkylene dicarboxylic acids (succinic acid, adipic acid, sebacic acid, etc.); alkenylene dicarboxylic acids (maleic acid, fumaric acid, etc.); aromatic dicarboxylic acids (phthalic acid, isophthalic acid, terephthalic acid) And naphthalenedicarboxylic acid). Of these, preferred are alkenylene dicarboxylic acids having 4 to 20 carbon atoms and aromatic dicarboxylic acids having 8 to 20 carbon atoms. Examples of the trivalent or higher polyvalent carboxylic acid (TC) include aromatic polycarboxylic acids having 9 to 20 carbon atoms (such as trimellitic acid and pyromellitic acid). In addition, as polyhydric carboxylic acid (PC), you may make it react with polyhydric alcohol (PO) using the above-mentioned acid anhydride or lower alkyl ester (Methyl ester, ethyl ester, isopropyl ester, etc.).

  The ratio of the polyhydric alcohol (PO) to the polycarboxylic acid (PC) is usually 2/1 to 1/1, preferably as the equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] and the carboxyl group [COOH]. Is 1.5 / 1 to 1/1, more preferably 1.3 / 1 to 1.02 / 1.

  Examples of the polyvalent isocyanate compound (PIC) 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.); isocyanates; Those blocked with caprolactam or the like; and combinations of two or more of these.

  The ratio of the polyvalent isocyanate compound (PIC) is usually 5/1 to 1/1, preferably as an equivalent ratio [NCO] / [OH] of the isocyanate group [NCO] and the hydroxyl group [OH] of the polyester having a hydroxyl group. 4/1 to 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, when a urea-modified polyester is used, the urea content in the ester is lowered and hot offset resistance is deteriorated.

The content of the polyvalent isocyanate compound (PIC) component in the polyester prepolymer (A) having an isocyanate group is usually 0.5 to 40 wt%, preferably 1 to 30 wt%, more preferably 2 to 20 wt%. . If it is less than 0.5 wt%, 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 wt%, the low-temperature fixability deteriorates.
The number of isocyanate groups contained per molecule in the polyester prepolymer (A) having an isocyanate group is usually 1 or more, preferably 1.5 to 3 on average, more preferably 1.8 to 2 on average. Five. If it is less than 1 per molecule, the molecular weight of the urea-modified polyester will be low, and the hot offset resistance will deteriorate.

Next, as amines (B) to be reacted with the polyester prepolymer (A), a divalent amine compound (B1), a trivalent or higher polyvalent amine compound (B2), an amino alcohol (B3), an amino mercaptan (B4) ), Amino acid (B5), and amino acid block of B1 to B5 (B6).
Examples of the divalent amine compound (B1) include aromatic diamines (phenylenediamine, diethyltoluenediamine, 4,4′-diaminodiphenylmethane, etc.); alicyclic diamines (4,4′-diamino-3,3′-dimethyldicyclohexyl). Methane, diamine cyclohexane, isophorone diamine, etc.); and aliphatic diamines (ethylene diamine, tetramethylene diamine, hexamethylene diamine, etc.) and the like. Examples of the trivalent or higher polyvalent amine compound (B2) include diethylenetriamine and triethylenetetramine. Examples of amino alcohol (B3) include ethanolamine and hydroxyethylaniline. Examples of amino mercaptan (B4) include aminoethyl mercaptan and aminopropyl mercaptan. Examples of the amino acid (B5) include aminopropionic acid and aminocaproic acid. Examples of the compound (B6) obtained by blocking the amino group of B1 to B5 include ketimine compounds and oxazolidine compounds obtained from the amines of B1 to B5 and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.). Among these amines (B), preferred are B1 and a mixture of B1 and a small amount of B2.

The ratio of amines (B) is equivalent to the equivalent ratio [NCO] / [NHx] of isocyanate groups [NCO] in the polyester prepolymer (A) having isocyanate groups and amino groups [NHx] in amines (B). Is usually 1/2 to 2/1, preferably 1.5 / 1 to 1 / 1.5, more preferably 1.2 / 1 to 1 / 1.2. When [NCO] / [NHx] is more than 2 or less than 1/2, the molecular weight of the urea-modified polyester is lowered, and the hot offset resistance is deteriorated.
The urea-modified polyester may contain a urethane bond together with a urea bond. The molar ratio of the urea bond content to the urethane bond content is usually 100/0 to 10/90, preferably 80/20 to 20/80, and more preferably 60/40 to 30/70. When the molar ratio of the urea bond is less than 10%, the hot offset resistance is deteriorated.

The modified polyester (i) used in the present invention is produced by a one-shot method or a prepolymer method. The weight average molecular weight of the modified polyester (i) is usually 10,000 or more, preferably 20,000 to 10,000,000, more preferably 30,000 to 1,000,000. The peak molecular weight at this time is preferably 1000 to 10000. When the molecular weight is less than 1000, the elongation reaction hardly occurs, the elasticity of the toner is small, and as a result, the resistance to hot offset deteriorates. On the other hand, when it exceeds 10,000, the problem in production becomes high in the deterioration of fixability, particle formation and pulverization. The number average molecular weight of the modified polyester (i) is not particularly limited when the unmodified polyester (ii) described later is used, and may be a number average molecular weight that can be easily obtained to obtain the weight average molecular weight. (I) When used alone, the number average molecular weight is usually 20000 or less, preferably 1000 to 10000, and more preferably 2000 to 8000. When it exceeds 20000, the low-temperature fixability and the glossiness when used in a full-color device are deteriorated.
In the crosslinking and / or extension reaction between the polyester prepolymer (A) and the amines (B) to obtain the modified polyester (i), a reaction terminator is used as necessary to adjust the molecular weight of the resulting urea-modified polyester. be able to. Examples of the reaction terminator include monoamines (diethylamine, dibutylamine, butylamine, laurylamine, etc.), and those obtained by blocking them (ketimine compounds).
The molecular weight of the polymer produced can be measured using gel permeation chromatography (GPC) with THF as a solvent.

(Unmodified polyester)
In the present invention, not only the modified polyester (i) is used alone, but also the unmodified polyester (ii) can be contained as a binder resin component together with the (i). By using (ii) in combination, the low-temperature fixability and the gloss when used in a full-color device are improved, which is preferable to single use. Examples of (ii) include polycondensates of polyhydric alcohol (PO) and polyvalent carboxylic acid (PC) similar to the polyester component of (i), and preferred ones are also the same as (i). . (Ii) is not limited to unmodified polyester, but may be modified with a chemical bond other than a urea bond, and may be modified with a urethane bond, for example. It is preferable that (i) and (ii) are at least partially compatible in terms of low-temperature fixability and hot offset resistance. Accordingly, the polyester component (i) and (ii) preferably have similar compositions. When (ii) is contained, the weight ratio of (i) to (ii) is usually 5/95 to 80/20, preferably 5/95 to 30/70, more preferably 5/95 to 25/75, Particularly preferred is 7/93 to 20/80. When the weight ratio of (i) is less than 5%, the hot offset resistance is deteriorated, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability.

  The peak molecular weight of (ii) is usually 1000 to 10,000, preferably 2000 to 8000, and more preferably 2000 to 5000. If it is less than 1000, heat-resistant storage stability will deteriorate, and if it exceeds 10,000, low-temperature fixability will deteriorate. The hydroxyl value of (ii) is preferably 5 or more, more preferably 10 to 120, and particularly preferably 20 to 80. If it is less than 5, it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. The acid value of (ii) is preferably 1 to 5, more preferably 2 to 4. Since a high acid value wax is used as the wax, the low acid value binder leads to electrification and high volume resistance, so that it is easy to match the toner used for the two-component developer.

The glass transition point (Tg) of the binder resin is usually 35 to 70 ° C, preferably 55 to 65 ° C. If it is less than 35 ° C., the heat resistant storage stability of the toner is deteriorated, and if it exceeds 70 ° C., the low-temperature fixability is insufficient. Since the urea-modified polyester is likely to be present on the surface of the obtained toner base particles, the toner of the present invention tends to have good heat storage stability even when the glass transition point is low, as compared with known polyester-based toners. Show.
The glass transition point (Tg) can be measured with a differential scanning calorimeter (DSC).

(Coloring agent)
As the colorant, all known dyes and pigments can be used. 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, Red Dan, Lead Zhu, Cadmium Red, Cadmium Mercury Red, Antimon Zhu, Permanent Red 4R, Para Red, Phi Sayred, Parachlor Ortonito Aniline Red, Resol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmin Min BS, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Resol 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, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thio Indigo Red B, Thioindigo Maroon, Oil Red, Quinacridone Red, Pyrazolone Red Polyazo Red, Chrome Vermillion, 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, chromium oxide, pyridian, emerald green, pigment Green B, Naphthol Green B, Green Gold, Acid Green Lake, Malachite Green Lake, Lid Russian nin green, anthraquinone green, titanium oxide, zinc white, litbon and mixtures thereof can be used. The content of the colorant is usually 1 to 15% by weight, preferably 3 to 10% by weight, based on the toner.

  The colorant can also be used as a master batch combined with a resin. As a binder resin to be kneaded with the production of the master batch or the master batch, a polymer of styrene such as polystyrene, poly-p-chlorostyrene, polyvinyl toluene or the like, or a copolymer of these and a vinyl compound, Polymethyl methacrylate, polybutyl 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, fat Aromatic or alicyclic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffins, paraffin waxes and the like can be mentioned, and these can be used alone or in combination.

(Charge control agent)
Known charge control agents can be used, such as nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (fluorine-modified 4 Secondary ammonium salts or compounds, tungsten simple substances or compounds, fluorine activators, salicylic acid metal salts, and metal salts of salicylic acid derivatives. Specifically, Bontron 03 of a nigrosine dye, Bontron P-51 of a quaternary ammonium salt, Bontron S-34 of a metal-containing azo dye, E-82 of an oxynaphthoic acid metal complex, E-84 of a salicylic acid metal complex , Phenolic condensate E-89 (above, Orient Chemical Industries, Ltd.), quaternary ammonium salt molybdenum complex TP-302, TP-415 (above, Hodogaya Chemical Co., Ltd.), quaternary ammonium salt copy Charge PSY VP2038, copy blue PR of triphenylmethane derivative, copy charge of quaternary ammonium salt NEG VP2036, copy charge NX VP434 (manufactured by Hoechst), LRA-901, LR-147 which is a boron complex (Nippon Carlit) Manufactured), copper phthalocyanine, perylene, quinacridone, azo series Fee, a sulfonic acid group, a carboxyl group, and polymer compounds having a functional group such as quaternary ammonium salts. Of these, substances that control the negative polarity of the toner are particularly preferably used.
The amount of the charge control agent used is determined by the type of binder resin, the presence or absence of additives used as necessary, and the toner production method including the dispersion method, and 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 charge control agent is reduced, the electrostatic attraction with the developing roller is increased, the flowability of the developer is lowered, and the image density is lowered. Invite.

(Release agent)
As a release agent, a low melting point wax having a melting point of 50 to 120 ° C. works more effectively as a release agent in the dispersion with the binder resin between the fixing roller and the toner interface. The effect on high temperature offset is exhibited without applying a release agent such as oil. Examples of such a wax component include the following. Examples of waxes and waxes include plant waxes such as carnauba wax, cotton wax, wood wax, rice wax, animal waxes such as beeswax and lanolin, mineral waxes such as ozokerite and cercin, and paraffin, microcrystalline, And petroleum waxes such as petrolatum. In addition to these natural waxes, synthetic hydrocarbon waxes such as Fischer-Tropsch wax and polyethylene wax, and synthetic waxes such as esters, ketones, and ethers can be used. Furthermore, fatty acid amides such as 12-hydroxystearic acid amide, stearic acid amide, phthalic anhydride imide, chlorinated hydrocarbon, and low molecular weight crystalline polymer resin, poly-n-stearyl methacrylate, poly-n- A crystalline polymer having a long alkyl group in the side chain such as a homopolymer or copolymer of polyacrylate such as lauryl methacrylate (for example, a copolymer of n-stearyl acrylate-ethyl methacrylate, etc.) can also be used. .
The charge control agent and the release agent can be melt-kneaded together with the master batch and the binder resin, and of course, they may be added when dissolved and dispersed in the organic solvent.

(External additive)
Inorganic fine particles are preferably used as an external additive for assisting the fluidity, developability and chargeability of the toner particles. The primary particle diameter of the inorganic fine particles is preferably 5 × ¹⁰ -3 ~2μm, it is particularly preferably 5 × ¹⁰ -3 ~0.5μm. Moreover, it is preferable that the specific surface area by BET method is 20-500 m < ² > / g. The use ratio of the inorganic fine particles is preferably 0.01 to 5 wt% of the toner, and particularly preferably 0.01 to 2.0 wt%.
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, quartz sand, clay, mica, wollastonite, diatomaceous earth. Examples include soil, chromium oxide, cerium oxide, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride. Among these, as the fluidity imparting agent, it is preferable to use hydrophobic silica fine particles and hydrophobic titanium oxide fine particles in combination. In particular, when stirring and mixing are performed using particles having an average particle diameter of 5 × 10 ⁻² μm or less, the electrostatic force and van der Waals force with the toner are remarkably improved. Even when stirring and mixing inside the developing device is performed to obtain a good image quality that does not cause the release of the fluidity imparting agent from the toner and does not generate firefly, etc., and further reduces the residual toner. It is done.
Titanium oxide fine particles are excellent in environmental stability and image density stability, but have a tendency to deteriorate the charge rise characteristics. Therefore, if the amount of titanium oxide fine particles added is larger than the amount of silica fine particles added, this side effect is affected. It can be considered large. However, when the added amount of the hydrophobic silica fine particles and the hydrophobic titanium oxide fine particles is in the range of 0.3 to 1.5 wt%, the charge rising characteristics are not greatly impaired, and the desired charge rising characteristics can be obtained, that is, repeated copying. Stable image quality can be obtained even if

Next, a toner manufacturing method will be described. Here, although a preferable manufacturing method is shown, it is not limited to this.
(Toner production method)
1) A toner material solution is prepared by dispersing a colorant, unmodified polyester, a polyester prepolymer having an isocyanate group, and a release agent in an organic solvent.
The organic solvent is preferably volatile with a boiling point of less than 100 ° C. from the viewpoint of easy removal after toner base particle formation. Specifically, 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 an organic solvent is 0-300 weight part normally with respect to 100 weight part of polyester prepolymers, Preferably it is 0-100 weight part, More preferably, it is 25-70 weight part.

2) The toner material liquid is emulsified in an aqueous medium in the presence of a surfactant and resin fine particles.
The aqueous medium may be water alone or an organic solvent such as alcohol (methanol, isopropyl alcohol, ethylene glycol, etc.), dimethylformamide, tetrahydrofuran, cellosolves (methyl cellosolve, etc.), lower ketones (acetone, methyl ethyl ketone, etc.). It may be included.
The amount of the aqueous medium used relative to 100 parts by weight of the toner material liquid is usually 50 to 2000 parts by weight, preferably 100 to 1000 parts by weight. If the amount is less than 50 parts by weight, the dispersion state of the toner material liquid is poor, and toner particles having a predetermined particle diameter cannot be obtained. If it exceeds 20000 parts by weight, it is not economical.

Further, in order to improve the dispersion in the aqueous medium, a dispersant such as a surfactant and resin fine particles is appropriately added.
As surfactants, anionic surfactants such as alkylbenzene sulfonates, α-olefin sulfonates, phosphate esters, alkylamine salts, amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, amine salt types such as imidazoline, Quaternary ammonium salt type cationic surfactants such as alkyltrimethylammonium salt, dialkyldimethylammonium salt, alkyldimethylbenzylammonium salt, pyridinium salt, alkylisoquinolinium salt, benzethonium chloride, fatty acid amide derivative, polyhydric alcohol Nonionic surfactants such as derivatives, for example, amphoteric surfactants such as alanine, dodecyldi (aminoethyl) glycine, di (octylaminoethyl) glycine and N-alkyl-N, N-dimethylammonium 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- [ω-fluoroalkyl (C6-C11 ) Oxy] -1-alkyl (C3-C4) sodium sulfonate, 3- [ω-fluoroalkanoyl (C6-C8) -N-ethylamino] -1-propanesulfonic acid sodium, fluoroalkyl (C11-C20) carvone Acids and metal salts, 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) Perful Olooctanesulfonamide, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (C6-C10) -N-ethylsulfonylglycine salt, monoperfluoroalkyl (C6-C16) ethyl phosphate, etc. Can be mentioned.
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 (manufactured by Daikin Industries, Ltd.), Megafac F-110, F-120, F-113, F-191, F-812, F-833 (manufactured by Dainippon Ink, Inc.), 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).

  Moreover, as the cationic surfactant, aliphatic quaternary ammonium such as aliphatic primary, secondary or secondary amic acid, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt which has a right fluoroalkyl group is used. Salt, benzalkonium salt, benzethonium chloride, pyridinium salt, imidazolinium salt, trade names include Surflon S-121 (Asahi Glass Co., Ltd.), Florard FC-135 (Sumitomo 3M Co., Ltd.), Unidyne DS-202 (Daikin Industries) Smoke), Megafac F-150, F-824 (Dainippon Ink Co., Ltd.), Xtop EF-132 (Tochem Products), Footage F-300 (Neos), and the like.

The resin fine particles are added to stabilize the toner base particles formed in the aqueous medium. For this reason, it is preferable to add so that the coverage existing on the surface of the toner base particles is in the range of 10 to 90%. For example, polymethyl methacrylate fine particles 1 μm and 3 μm, polystyrene fine particles 0.5 μm and 2 μm, poly (styrene-acrylonitrile) fine particles 1 μm, trade names are PB-200H (manufactured by Kao), SGP (manufactured by Soken), Techno Examples include polymer SB (manufactured by Sekisui Chemical Co., Ltd.), SGP-3G (manufactured by Sokensha), and micropearl (manufactured by Sekisui Fine Chemical Co., Ltd.).
In addition, inorganic compound dispersants such as tricalcium phosphate, calcium carbonate, titanium oxide, colloidal silica, and hydroxyapatite can also be used.

  As a dispersant that can be used in combination with the above resin fine particles and inorganic compound dispersant, the dispersed droplets may be stabilized by a polymer protective colloid. 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 acrylic acid-β-hydroxyethyl, methacrylic acid-β-hydroxyethyl, acrylic acid-β-hydroxypropyl, methacrylic acid-β-hydroxypropyl, acrylic acid-γ-hydroxypropyl, methacrylic acid-γ-hydroxy Propyl, acrylic acid-3-chloro-2-hydroxypropyl, methacrylic acid-3-chloro-2-hydroxypropyl, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerol monoacrylate, glycerol monomethacrylate Luric acid esters, 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 compounds containing vinyl alcohol and a carboxyl group Esters such as 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 Nitrogen compounds such as imidazole and ethyleneimine, or homopolymers or copolymers such as those having a heterocyclic ring thereof, polyoxyethylene, poly Xoxypropylene, polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, polyoxy Polyoxyethylenes such as ethylene nonylphenyl ester, celluloses such as methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose can be used.

  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. Among these, the high-speed shearing method is preferable in order to make the particle size of the dispersion 2 to 20 μm. When a high-speed shearing disperser is used, the rotational speed is not particularly limited, but is usually 1000 to 30000 rpm, preferably 5000 to 20000 rpm. The dispersion time is not particularly limited, but in the case of a batch method, it is usually 0.1 to 5 minutes. The temperature during dispersion is usually 0 to 150 ° C. (under pressure), preferably 40 to 98 ° C.

3) At the same time as the preparation of the emulsion, the amines (B) are added to cause a reaction with the polyester prepolymer (A) having an isocyanate group.
This reaction involves molecular chain crosslinking and / or elongation. The reaction time is selected depending on the reactivity between the isocyanate group structure of the polyester prepolymer (A) and the amines (B), but is usually 10 minutes to 40 hours, preferably 2 to 24 hours. The reaction temperature is generally 0 to 150 ° C, preferably 40 to 98 ° C. Moreover, a well-known catalyst can be used as needed. Specific examples include dibutyltin laurate and dioctyltin laurate.

4) After completion of the reaction, the organic solvent is removed from the emulsified dispersion (reactant), washed and dried to obtain toner base particles.
In order to remove the organic solvent, the temperature of the entire system is gradually raised in a laminar stirring state, and after giving strong stirring in a certain temperature range, the solvent base is removed to produce spindle-shaped toner base particles. . Further, when an acid such as calcium phosphate salt or an alkali-soluble material is used as the dispersion stabilizer, the calcium phosphate salt is dissolved from the toner base particles by a method such as dissolving the calcium phosphate salt with an acid such as hydrochloric acid and washing with water. Remove. It can also be removed by operations such as enzymatic degradation.

5) A charge control agent is injected into the toner base particles obtained above, and then inorganic fine particles such as silica fine particles and titanium oxide fine particles are externally added to obtain a toner.
The injection of the charge control agent and the external addition of the inorganic fine particles are performed by a known method using a mixer or the like.
Thereby, a toner having a small particle size and a sharp particle size distribution can be easily obtained. Furthermore, by giving strong agitation in the process of removing the organic solvent, the shape between the true spherical shape and the rugby ball shape can be controlled, and the surface morphology is also controlled between the smooth shape and the umeboshi shape. be able to.

An image forming apparatus using the electrostatic latent image developing carrier of the present invention as a developer will be described.
FIG. 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to the present invention. In the figure, reference numeral 100 is a copying apparatus main body, 200 is a paper feed table on which the copying apparatus is placed, 300 is a scanner mounted on the copying apparatus main body 100, and 400 is an automatic document feeder (ADF) mounted thereon.
The copying apparatus main body 100 has a tandem type in which four image forming units 18 each having various units for performing an electrophotographic process such as charging, developing, and cleaning are arranged in parallel around a photosensitive member 40 as a latent image carrier. An image forming apparatus 20 is provided. Above the tandem image forming apparatus 20, there is provided an exposure apparatus 21 that exposes the photoreceptor 40 with laser light based on image information to form a latent image. Further, an intermediate transfer belt 10 made of an endless belt member is provided at a position facing each photoconductor 40 of the tandem type image forming apparatus 20. A primary transfer unit 62 for transferring the toner images of the respective colors formed on the photoconductor 40 to the intermediate transfer belt 10 is disposed at a position facing the photoconductor 40 via the intermediate transfer belt 10.
A secondary transfer device 22 that collectively transfers the toner images superimposed on the intermediate transfer belt 10 onto transfer paper conveyed from the paper feed table 200 is disposed below the intermediate transfer belt 10. The secondary transfer device 22 is configured by spanning a secondary transfer belt 24 that is an endless belt between two rollers 23, and is disposed by pressing against the support roller 16 via the intermediate transfer belt 10. The toner image on 10 is transferred onto a transfer sheet. A fixing device 25 for fixing the image on the transfer paper is provided beside the secondary transfer device 22. The fixing device 25 is configured by pressing a pressure roller 27 against a fixing belt 26 that is an endless belt.
The secondary transfer device 22 described above also has a sheet transport function for transporting the transfer paper after image transfer to the fixing device 25. Of course, a transfer roller or a non-contact charger may be arranged as the secondary transfer device 22, and in such a case, it is difficult to provide this sheet conveyance function together.
In the illustrated example, a reversing device 28 for reversing the transfer paper so as to record images on both sides of the transfer paper is provided below the secondary transfer device 22 and the fixing device 25 in parallel with the tandem image forming device 20 described above. .

  The developing device 4 of the image forming means 18 uses a developer containing the electrostatic latent image developing carrier of the present invention. In the developing device 4, the developer carrying member carries and conveys the developer, and an alternating electric field is applied at a position facing the photoconductor 40 to develop the latent image on the photoconductor 40. By applying the alternating electric field, the developer is activated, the charge amount distribution of the toner can be narrowed, and the developability can be improved.

  Further, the developing device 4 can be a process cartridge that is integrally supported together with the photoreceptor 40 and is detachably formed on the main body of the image forming apparatus. In addition, the process cartridge may include a charging unit and a cleaning unit.

The operation of the image forming apparatus is as follows.
First, a document is set on the document table 30 of the automatic document feeder 400, or the automatic document feeder 400 is opened and a document is set on the contact glass 32 of the scanner 300, and the automatic document feeder 400 is closed. Hold it down.
When a start switch (not shown) is pressed, when the document is set on the automatic document feeder 400, the document is transported and moved onto the contact glass 32, and then the document is set on the other contact glass 32. At that time, the scanner 300 is immediately driven to travel the first traveling body 33 and the second traveling body 34. Then, the first traveling body 33 emits light from the light source and further reflects the reflected light from the document surface toward the second traveling body 34 and reflects by the mirror of the second traveling body 34 and passes through the imaging lens 35. The document is placed in the reading sensor 36 and the original content is read.

  When a start switch (not shown) is pressed, one of the support rollers 14, 15 and 16 is rotationally driven by a drive motor (not shown), the other two support rollers are driven to rotate, and the intermediate transfer belt 10 is rotated and conveyed. To do. At the same time, the individual image forming means 18 rotates the photoconductor 40 to form black, yellow, magenta, and cyan monochrome images on each photoconductor 40. Then, along with the conveyance of the intermediate transfer belt 10, the monochrome images are sequentially transferred to form a composite color image on the intermediate transfer belt 10.

On the other hand, when a start switch (not shown) is pressed, one of the paper feed rollers 42 of the paper feed table 200 is selectively rotated, and the sheet is fed out from one of the paper feed cassettes 44 provided in multiple stages in the paper bank 43, and the separation roller 45. Then, the sheets are separated one by one into the paper feed path 46, transported by the transport roller 47, guided to the paper feed path 48 in the copying machine main body 100, and abutted against the registration roller 49 and stopped.
Alternatively, the sheet feed roller 50 is rotated to feed out the sheets on the manual feed tray 51, separated one by one by the separation roller 52, put into the manual feed path 53, and abutted against the registration roller 49 and stopped.
Then, the registration roller 49 is rotated in synchronization with the composite color image on the intermediate transfer belt 10, the sheet is fed between the intermediate transfer belt 10 and the secondary transfer device 22, and is transferred by the secondary transfer device 22. A color image is recorded on the sheet.

The image-transferred sheet is conveyed by the secondary transfer device 22 and sent to the fixing device 25. The fixing device 25 applies heat and pressure to fix the transferred image, and then the switching roller 55 is used to switch the discharge image. The paper is discharged at 56 and stacked on the paper discharge tray 57. Alternatively, it is switched by the switching claw 55 and put into the sheet reversing device 28, where it is reversed and guided again to the transfer position, and an image is recorded also on the back surface, and then discharged onto the discharge tray 57 by the discharge roller 56.
On the other hand, the intermediate transfer belt 10 after the image transfer is removed by the intermediate transfer belt cleaning device 17 to remove residual toner remaining on the intermediate transfer belt 10 after the image transfer, so that the tandem image forming apparatus 20 can prepare for the image formation again.

  Hereinafter, the present invention will be specifically described by way of examples. However, the present embodiment is merely an example of the present invention, and the present invention is not limited to these embodiments. The “parts” and “wt%” shown below are based on weight.

(Example of manufacturing yellow toner)
~ Synthesis of low molecular weight polyester ~
In a reaction vessel equipped with a condenser, a stirrer and a nitrogen inlet tube, 229 parts of bisphenol A ethylene oxide 2-mole adduct, 529 parts of bisphenol A propylene oxide 3-mole adduct, 208 parts terephthalic acid, 46 parts adipic acid and dibutyl Add 2 parts of tin oxide, react for 7 hours at 230 ° C under normal pressure, and then react for 5 hours under reduced pressure of 10-15mmHg, then put 44 parts of trimellitic anhydride into the reaction vessel at 180 ° C at normal pressure. The mixture was reacted for 3 hours to obtain a low molecular weight polyester. The low molecular weight polyester had a number average molecular weight of 2,300, a weight average molecular weight of 6,700, a Tg of 43 ° C., and an acid value of 25.

~ Synthesis of prepolymer ~
In a reaction vessel equipped with a condenser, a stirrer and a nitrogen introduction tube, 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, 22 parts of trimellitic anhydride Then, 2 parts of dibutyltin oxide was added and reacted at normal pressure and 230 ° C. for 7 hours, and further reacted at reduced pressure of 10 to 15 mmHg for 5 hours to obtain an intermediate polyester. The intermediate polyester had a number average molecular weight of 2200, a weight average molecular weight of 9700, Tg of 54 ° C., an acid value of 0.5, and a hydroxyl value of 52.
Next, 410 parts of intermediate polyester, 89 parts of isophorone diisocyanate, and 500 parts of ethyl acetate were 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 to obtain a prepolymer. . The free isocyanate weight percent of the prepolymer was 1.53%.

~ Synthesis of ketimine ~
A reaction vessel equipped with a stir bar and a thermometer was charged with 170 parts of isophoronediamine and 75 parts of methyl ethyl ketone, and reacted at 50 ° C. for 4 hours and a half to obtain a ketimine compound. The amine value of the ketimine compound was 417.

~ Production of master batch ~
Add 30 parts of water, 50 parts of CI Pigment Yellow 155 (Toner Yellow 3GP: Clariant), 50 parts of low molecular weight polyester, 6 parts of pigment dispersant (Solsperse S24000sc: Avecia) and mix with a Henschel mixer (Mitsui Mining Co., Ltd.) Thus, a mixture in which water was soaked into the pigment aggregate was obtained. The mixture was kneaded with two rolls at 130 ° C. for 45 minutes, rolled and cooled, and pulverized with a pulverizer to obtain a master batch.

~ Preparation of oil phase ~
A container equipped with a stir bar and a thermometer was charged with 378 parts of low molecular weight polyester, 110 parts of synthetic ester WAX, 22 parts of a charge control agent (salicylic acid metal complex E-84: manufactured by Orient Chemical Industries), and 947 parts of ethyl acetate. The temperature was raised to 80 ° C., kept at 80 ° C. for 5 hours, and then cooled to 30 ° C. in 1 hour. Next, 500 parts of a master batch and 500 parts of ethyl acetate were charged in a container and mixed for 1 hour to obtain a raw material solution.
1324 parts of the raw material solution is transferred to a container and filled with 80% by volume of 0.5 mm zirconia beads using a bead mill (Ultra Visco Mill, manufactured by Imex) with a liquid feed speed of 1 kg / hr, a disk peripheral speed of 6 m / sec. The pigment and WAX were dispersed under the pass conditions. Next, 1324 parts of a 65% ethyl acetate solution of low molecular weight polyester was added, and one pass was performed with a bead mill under the above conditions to obtain a pigment / WAX dispersion. The solid content concentration (130 ° C., 30 minutes) of the pigment / WAX dispersion was 50%.

~ Emulsification, solvent removal ~
664 parts of pigment / WAX dispersion, 139 parts of prepolymer and 5.9 parts of ketimine compound are put in a container, mixed with TK homomixer (manufactured by Special Machine) for 1 minute at 5,000 rpm, and then the aqueous phase is put into the container. The mixture was added and mixed with a TK homomixer at a rotational speed of 13,000 rpm for 20 minutes to obtain an emulsified slurry.
The emulsified slurry was put into a container equipped with a stirrer and a thermometer, and after removing the solvent at 30 ° C. for 8 hours, aging was performed at 45 ° C. for 4 hours to obtain a dispersed slurry.

~ Washing, drying ~
After filtering 100 parts of the emulsified slurry under reduced pressure,
(1) 100 parts of ion-exchanged water was added to the filter cake, mixed with a TK homomixer (rotation speed: 12,000 rpm for 10 minutes), and then filtered.
(2) 100 parts of 10% aqueous sodium hydroxide solution was added to the filter cake of (1), mixed with a TK homomixer (30 minutes at 12,000 rpm), and then filtered under reduced pressure.
(3) 100 parts of 10% hydrochloric acid was added to the filter cake of (2), mixed with a TK homomixer (rotation speed: 12,000 rpm for 10 minutes), and then filtered.
(4) 300 parts of ion-exchanged water was added to the filter cake of (3), mixed with a TK homomixer (rotation speed: 12,000 rpm for 10 minutes), and then filtered twice to obtain a filter cake.
The filter cake was dried at 45 ° C. for 48 hours in a circulating drier and sieved with a mesh of 75 μm, and then 100 parts of toner particles were coated with 0.5 parts of hydrophobic silica and 0.5 parts of hydrophobic titanium oxide. The yellow toner was obtained by mixing with a Henschel mixer.

(Example of carrier production)
<Production Example 1>
Using a homogenizer, a solution prepared so that the conductive carbon (Ketjen Black EC-DJ600: Lion Akzo) is 7 wt% based on the solid content of the silicone resin (SR2411: manufactured by Toray Dow Corning Silicone) Then, after dispersing for 30 minutes, the dispersion was diluted to a solid content of 10 wt% to obtain a coating layer coating solution.
Next, with respect to the carrier core material (CuZn ferrite: 1 kOe magnetic moment 66 emu / g, weight average particle size 35 μm), the above dispersion is about 100 ° C. in an atmosphere at about 100 ° C. The coating was applied at a rate of 50 g / min. Furthermore, it heated at 280 degreeC for 2 hours, and obtained the carrier A whose average layer thickness of a coating layer is 0.5 micrometer. The layer thickness was adjusted by adjusting the amount of the coating solution. The volume resistivity of this carrier A was 3 × 10 ¹⁵ Ω · cm, and the particle size distribution was measured. As a result, the proportion of carriers having a particle size of 12 μm or less to the entire carrier was 0.5% by number.
100 parts of carrier A prepared above and 5 parts of yellow toner were mixed and stirred using a turbula shaker mixer (TypeT2F), and then only the yellow toner was sucked and removed.

<Production Example 2>
A carrier was produced in the same manner as in Production Example 1, but mixing with yellow toner, stirring, suction, and removal were not performed.

<Production Example 3>
Carrier B was produced in exactly the same manner as in Production Example 1, except that the conductive carbon in the coating layer coating solution was adjusted to 10 wt%. The electric resistance of the carrier B was 2 × 10 ¹⁰ Ω · cm.
After mixing and stirring 100 parts of this carrier B and 5 parts of yellow toner, only the yellow toner was sucked and removed.

<Production Example 4>
Hydrophobic silica 0.5 part and hydrophobic titanium oxide 0.5 part were added to and mixed with 100 parts of carrier A produced in the same manner as in Production Example 1 and 100 parts of fine powder or coarse powder produced during the production of yellow toner. After 5 parts were mixed and stirred, only the yellow toner coarse powder or fine powder was removed by suction.

<Production Example 5>
Carrier A produced in the same manner as in Production Example 1 was placed in a developing device having a cylindrical body having a magnet held therein and stirred for 10 minutes. After mixing and stirring 100 parts of this carrier and 5 parts of yellow toner, only the yellow toner was sucked and removed.

<Production Example 6>
Carrier A produced in the same manner as in Production Example 1 was classified using an ultrasonic vibration sieve equipped with a sieve having an opening of 20 μm. After mixing and stirring 100 parts of this carrier and 5 parts of yellow toner, only the yellow toner was sucked and removed.

(Evaluation)
A developer was prepared by mixing and stirring 100 parts of the carrier shown in Carrier Production Examples 1 to 6 and 5 parts of yellow toner shown in the Yellow Toner Production Example. This developer was set on a pre-tail 500 (full color copying machine manufactured by Ricoh Co., Ltd.) and stirred for 10 minutes in a single color mode. After that, an image was taken, and color stains on the image portion, background stains and image quality were confirmed. As for color stains (visual observation), background stains, and image quality, “」 ”indicates that there is no problem at all,“ ◯ ”indicates that there is no problem in practical use, and“ x ”indicates that it is inappropriate.

上記式（１）において、△Ｌ^＊、Δａ^＊、Δｂ^＊は基準色と評価サンプルの明度Ｌ^＊の差、および色座標ａ^＊、ｂ^＊の差である。基準色としては、導電性カーボンを含まないキャリアとイエロートナーを混合した現像剤をプリテール５００にセットしてとった画像を用いた。
一般に、色差ΔＥ^＊ _ａｂが２．５以下であれば、サンプルを離して判定したときにほぼ同一と認めることができる、と言われている。 In addition to visual confirmation, color stain was evaluated by a color difference ΔE ^* _ab represented by the following formula (1) based on the L ^* a ^* b ^* color system of JIS Z8730.

In the above formula (1), ΔL ^* , Δa ^* and Δb ^* are the difference between the lightness L ^* of the reference color and the evaluation sample, and the difference between the color coordinates a ^* and b ^* . As the reference color, an image obtained by setting a developer containing a carrier containing no conductive carbon and yellow toner on the tail 500 was used.
In general, it is said that when the color difference ΔE ^* _ab is 2.5 or less, it can be recognized that the samples are almost the same when the samples are separated.

The evaluation results are shown in Table 1.

As shown in Table 1, the images output using the developers of Examples 1 to 5 containing the carrier of the present invention showed good results in terms of color stains, background stains, and image quality. On the other hand, in Comparative Example 1 using a developer that is a combination of a carrier and a yellow toner that has not been subjected to conductive carbon removal treatment, the background stain and the image quality were good, but a result inferior to the color stain was obtained.
The yellow toner in the developers of Examples 1 to 5 and Comparative Example 1 was collected and observed with an optical microscope. As a result, the black toner particles in the yellow toner of Comparative Example 1 were significantly different from those in Examples 1 to 5. It was confirmed that a lot was mixed. When this black foreign material was elementally analyzed by X-ray microanalysis (EPMA), C, O, and Si were detected uniformly from the entire black foreign material, but Fe was not detected. From this, it was found that the black foreign matter was formed by removing the conductive carbon adhering to the carrier surface.

1 is a schematic configuration diagram of an image forming apparatus according to the present invention.

Explanation of symbols

4 Developing device 10 Intermediate transfer belt (intermediate transfer member)
18 Image forming means 21 Exposure device 25 Fixing device 40 Photosensitive member (latent image carrier)
22 Secondary transfer device 62 Primary transfer means 100 Copier main body 200 Paper feed table 300 Scanner 400 Automatic document feeder

Claims (12)

A method for producing a carrier for developing an electrostatic latent image, comprising:
The step of coating the surface of the core made of magnetic material with a silicone resin in which conductive carbon is dispersed, and the carrier with the silicone resin coating layer formed is mixed and stirred together with the yellow toner, and then the yellow toner is sucked and removed. And removing the conductive carbon adhering to the surface of the silicone resin coating layer. A method for producing a carrier for developing an electrostatic latent image, comprising:   The electrostatic latent image developing method according to claim 1, wherein the yellow toner mixed with the carrier is a fine powder or a coarse powder toner generated during toner production. A method for producing a developing carrier.   3. The method for producing a carrier for developing an electrostatic latent image according to claim 1, wherein the step of removing the conductive carbon adhering to the surface of the silicone resin coating layer is performed before the mixing and stirring with the yellow toner. A method for producing a carrier for developing an electrostatic latent image, wherein the carrier on which a resin coating layer is formed is stirred alone.   The method for producing a carrier for developing an electrostatic latent image according to claim 3, wherein the stirring of the carrier alone on which the silicone resin coating layer is formed has a rotatable cylindrical body having at least a magnet held therein. A method for producing a carrier for developing an electrostatic latent image, comprising:   In the manufacturing method of the electrostatic latent image developing carrier according to any one of claims 1 to 4, after the step of coating the surface of the core made of the magnetic material with a silicone resin in which conductive carbon is dispersed, A method for producing a carrier for developing an electrostatic latent image, comprising a classification step.   The method for producing a carrier for developing an electrostatic latent image according to claim 5, wherein the classification step is performed using an ultrasonic vibration sieve. In the electrostatic latent image developing carrier formed by forming a coating layer of silicone resin in which conductive carbon is dispersed on the surface of the core material made of a magnetic material,
The electrostatic latent image developing carrier is an electrostatic latent image developing carrier manufactured by the electrostatic latent image developing carrier manufacturing method according to any one of claims 1 to 6.
When the weight average particle diameter of the carrier core material is 22 to 40 μm, the electrical resistance of the carrier is 10 ¹⁰ to 10 ¹⁶ Ω · cm when the applied voltage is 250 V / cm, and the thickness of the silicone resin coating layer is 0.3 to 1.5 μm. A carrier for developing an electrostatic latent image.   The carrier for developing an electrostatic latent image according to claim 7, wherein the proportion of the carrier having a particle diameter of 12 µm or less in the whole is 0.5% by number or less. A developer for developing an electrostatic latent image formed on a latent image carrier,
The developer is a two-component developer comprising the electrostatic latent image developing carrier according to claim 7 or 8 and a toner. A developing device for carrying and transporting a developer by a developer carrying member, forming an electric field at a position facing the latent image carrying member, and developing an electrostatic latent image on the latent image carrying member,
The developing device using the developer according to claim 9. A latent image carrier that carries the latent image and a developing unit that supplies toner to the electrostatic latent image formed on the surface of the latent image carrier to visualize the latent image are integrally supported to form an image. In the process cartridge formed detachably in the apparatus main body,
The process cartridge according to claim 10, wherein the developing unit is the developing device according to claim 10. A latent image carrier that carries a latent image, a charging unit that uniformly charges the surface of the latent image carrier, and the surface of the charged latent image carrier is exposed based on image data, whereby an electrostatic latent image is obtained. An exposure unit for writing, a developing unit for supplying toner to the electrostatic latent image formed on the surface of the latent image carrier and a visible image, and a visible image on the surface of the latent image carrier are transferred to a transfer target In an image forming apparatus comprising: a transfer unit that fixes; and a fixing unit that fixes a visible image on the transfer target.
The image forming apparatus according to claim 10, wherein the developing unit is the developing device according to claim 10.

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