JP5072646B2 - Image forming method and electrostatic image developing toner - Google Patents

Description

  The present invention relates to an image forming method and an electrostatic image developing toner for developing an electrostatic image in electrophotography. More specifically, the present invention relates to an image forming method capable of high-speed two-component development and an electrostatic charge image developing toner.

  Conventionally, in an image forming apparatus using an electrophotographic system such as a printer or a copying machine, a two-component developer containing a toner and a carrier is suitably used from the viewpoint of image quality, durability, and high-speed compatibility. In such a two-component development system, a developer magnetic brush is brought into contact with the photosensitive member in order to ensure a sufficient image density and to improve reproducibility of fine lines, and the peripheral speed of the developing sleeve relative to the peripheral speed of the photosensitive member. A method of speeding up and developing is used.

  On the other hand, in the recent electrophotographic industry, full-color, systematization, and digitization have progressed, and the demand for higher image quality, higher speed, and higher stability of output images has increased. Expected to enter the market. In order to break into the printing market with the electrophotographic method commonly used in copiers and various printers, high image quality and high stability are required even during long-term, high-speed process output. ing. In such an image forming apparatus in which the photosensitive member and the developing sleeve rotate at a high speed and continuously output an image as seen in the printing market for a long time, the stirring history and the stirring frequency with respect to the developer in the developer, more specifically, the toner The frequency of continuous contact between the carrier and the carrier is significantly different from that of a normal medium / low-speed rotating image forming apparatus. In addition, this difference is further increased by increasing the size of the developing device accompanying the increase in speed, resulting in a longer developer transport path.

  As described above, in an ultra-high-speed image forming apparatus in which the frequency of continuous contact between the toner and the carrier is remarkably high, a developer charge-up phenomenon occurs, resulting in a problem that the image density is lowered, and high stability. The goal of crystallization cannot be achieved.

  In order to suppress this charge-up phenomenon, in Patent Document 1 and Patent Document 2, toner obtained by externally adding two types of silica having different degrees of hydrophobicity to the toner surface is used. However, the toner proposed here cannot suppress charge-up in a high-speed image forming apparatus because the difference in hydrophobicity between the two types of externally added silica is small. In Patent Document 3, two different types of silica with an adjusted balance between the degree of hydrophobicity and the difference in particle size are externally added to the toner surface, which suppresses charge-up that occurs in an ultra-high-speed image forming apparatus. Is not enough.

On the other hand, as a binder resin for toner, a polyester resin is used in Patent Document 4 and a polyol resin is used in Patent Document 5 in order to obtain high image gloss and good color developability of a full-color image and a wide fixing temperature range. Has been. However, when the former polyester resin is used, agglomerates are likely to occur particularly in a toner bottle or a developing device in an ultra-high-speed image forming apparatus, and a phenomenon in which an image of a part where the agglomerates exists is whitened. Further, when the acid value of the polyester resin is high, environmental fluctuations are likely to occur, and in a low temperature and low humidity environment, charge-up is promoted and the image density is lowered. When the latter polyol resin is used, the generation of aggregates is suppressed, but due to the influence of the OH group of the polymer chain, it has a slight hygroscopicity in a high temperature and high humidity environment, thereby causing a charge-down phenomenon. As a result, problems such as toner scattering and background contamination occur, and the problem of high image quality cannot be achieved.
JP-A-11-231567 JP 2001-209209 A JP 2006-072093 A Japanese Patent Laid-Open No. 61-007844 JP 2003-173045 A

  The present invention relates to an image forming method using an ultra-high-speed image forming apparatus and an image forming method capable of simultaneously solving a charge-up with a continuous output for a long time and a charge-down in a high-temperature and high-humidity environment. An object is to provide a toner for developing an electrostatic image.

The characteristics of the present invention, which is a means for solving the above problems, will be described below.
1. In the image forming method having at least a charging step, an exposure step, a development step, a transfer step, and a fixing step, the developer used in the development step is at least a ratio EX / epoxy group (EX) to OH group (OH). A two-component developer comprising a toner containing, as a binder resin, a polyol-based resin having a plurality of OH groups in a molecular chain having an OH of 0.990 to 1.010, and a carrier, wherein the developing step includes at least the step A stirring / conveying step of conveying the developer while stirring and charging, wherein the stirring / conveying step includes at least a rotation speed α (rotation / conveyance) of a stirring / conveying means (excluding the developing means) for stirring and conveying the developer; min), a pitch beta (mm), the relationship of the conveying path length gamma (mm) is ^{1.0 × 10 6 ≦ α × β} × γ ≦ 16.0 × 10 6, the toner is the toner base particle And is composed of an outer additive, the toner base particles, the charging performance due to stirring of the carrier, the charge amount at the time of continuous stirring 3 min _{^{Q B / M 180 (-μC /}} g), 60 consecutive minutes As a ratio of charge amount Q ^B / M ₃₆₀₀ (−μC / g) when stirring, (Formula I),
(Formula I) 1.5 <[Q ^B / M ₃₆₀₀ ] / [Q ^B / M ₁₈₀ ] <2.5
The toner containing the external additive has a charge performance by stirring with the carrier of charge amount Q ^T / M ₁₈₀ (−μC / g) when stirring continuously for 3 minutes and charging when stirring continuously for 60 minutes. As a ratio of the quantity Q ^T / M ₃₆₀₀ (−μC / g), (Formula II)
(Formula II) 0.7 <[Q ^T / M ₃₆₀₀ ] / [Q ^T / M ₁₈₀ ] <1.3
The external additive includes at least two kinds of inorganic fine particles having different resistance values, and the particle size distribution Y and the addition amount X (however, the number of parts relative to 100 parts by weight of the toner base particles) of one external additive having a small resistance value are as follows: An image forming method characterized by satisfying the following (formula III):
(Formula III) 0.1 ≦ X ≦ 2.0
Y ≦ 2.6 × 10 ⁻³ X + 0.0048
2. 2. The image forming method as described in 1 above, wherein the adhesion rate represented by (formula IV) of the inorganic fine particle which is one of the external additives having a small resistance value is 65% to 95%.
(Formula IV) (M ₁ / M ₀ ) × 100 (%)
M ₁ : the weight of inorganic fine particles adhering to the surface of the toner base particles after dispersing the toner containing the external additive in an aqueous surfactant solution and ultrasonically treating it for 1 minute under the condition of a resonance frequency of 25 KHz;
M ₀ : Weight of inorganic fine particles adhering to the surface of the toner base before the ultrasonic treatment. 3. The image forming method as described in any one of 1 to 2 above, wherein the toner base particles have an average circularity of 0.910 to 0.970.
4). 4. The image forming method as described in any one of 1 to 3 above, wherein an inorganic fine particle as an external additive adhering to the surface of the toner base particle has a methanol hydrophobicity of 55% to 95%.
5. 5. The image forming method according to any one of 1 to 4, wherein the inorganic fine particle as one of the external additives having a small resistance value is titanium oxide subjected to a hydrophobic treatment.
6). A toner including at least a polyol-based resin having a plurality of OH groups in a molecular chain having a ratio EX / OH of 0.990 to 1.010 of epoxy group (EX) and OH group (OH) as a binder resin; An electrostatic charge image developing toner used in a two-component developer comprising: toner base particles and external additives, wherein the toner base particles have a charging performance by stirring with the carrier. As a ratio of the charge amount Q ^B / M ₁₈₀ (−μC / g) when continuously stirred for 3 minutes and the charge amount Q ^B / M ₃₆₀₀ (−μC / g) when continuously stirred for 60 minutes, (Formula I ) And
(Formula I) 1.5 <[Q ^B / M ₃₆₀₀ ] / [Q ^B / M ₁₈₀ ] <2.5
The toner containing the external additive has a charge performance by stirring with the carrier of charge amount Q ^T / M ₁₈₀ (−μC / g) when stirring continuously for 3 minutes and charging when stirring continuously for 60 minutes. As a ratio of the quantity Q ^T / M ₃₆₀₀ (−μC / g), (Formula II)
(Formula II) 0.7 <Q ^T / M ₃₆₀₀ / Q ^T / M ₁₈₀ <1.3
The external additive includes at least two kinds of inorganic fine particles having different resistance values, and the particle size distribution Y and the addition amount X (however, the number of parts relative to 100 parts by weight of the toner base particles) of one external additive having a small resistance value are as follows: An electrostatic charge image developing toner satisfying the following (formula III):
(Formula III) 0.1 ≦ X ≦ 2.0
Y ≦ 2.6 × 10 ⁻³ X + 0.0048
7). 7. The electrostatic image developing toner according to 6 above, wherein the adhesion ratio represented by (formula IV) of the inorganic fine particles as one of the external additives having a small resistance value is 65% to 95%. .
(Formula IV) (M ₁ / M ₀ ) × 100 (%)
M ₁ : the weight of inorganic fine particles adhering to the surface of the toner base particles after dispersing the toner containing the external additive in an aqueous surfactant solution and ultrasonically treating it for 1 minute under the condition of a resonance frequency of 25 KHz;
M ₀ : Weight of inorganic fine particles adhering to the surface of the toner base before ultrasonic treatment 8. 8. The toner for developing an electrostatic charge image according to any one of 6 to 7, wherein the toner base particles have an average circularity of 0.910 to 0.970.
9. 9. The electrostatic charge image development according to any one of 6 to 8, wherein the inorganic fine particles, which are external additives attached to the surface of the toner base particles, have a methanol hydrophobicity of 55% to 95%. Toner.
10. 10. The electrostatic image developing toner according to any one of items 6 to 9, wherein the inorganic fine particle as one of the external additives having a small resistance value is titanium oxide subjected to a hydrophobic treatment.

  According to the present invention, in an image forming method using an ultra-high-speed image forming apparatus and an electrostatic charge image developing toner, image formation capable of simultaneously solving a charge-up with continuous output for a long time and a charge-down in a high-temperature and high-humidity environment. Methods and toners for developing electrostatic images can be provided.

Hereinafter, the present invention will be described in more detail.
In one aspect, the present inventors use inorganic fine particles having two different resistance values for the toner to which inorganic fine particles are added on the surface of the toner base particles, and balance the particle size distribution and the addition amount of the inorganic fine particles having a small resistance value. As a two-component developer in an ultra-high-speed image forming apparatus, mechanical and process conditions in which the continuous contact frequency between the toner and the carrier in the developing device is significantly larger than that of an intermediate-to-low-speed image forming apparatus. It was found that a stable image can be provided over a long period of time even when used in the above. Furthermore, it has been found that by increasing the adhesion state of the inorganic fine particles having a small resistance value on the surface of the toner base particles, a stable image can be provided for a longer period of time.
Among the two types of inorganic fine particles adhering to the surface of the toner base particles, the inorganic fine particles having a large resistance value increase the toner charge amount by rubbing with the carrier and the like, while the inorganic fine particles having a small resistance value are rubbing with the carrier and the like. Leak toner charge. In the developer of an ultra-high speed image forming apparatus in which the frequency of continuous contact between the toner and the carrier is much higher than the image forming apparatus of medium to low speed, the charge up occurs frequently. Therefore, it is necessary to leak this charge up amount. is there. The present inventors have found that the above problem can be solved by adjusting the balance between the particle size distribution and the addition amount of inorganic fine particles having a small resistance value, which is a charge leakage component.

That is, when the particle size distribution of the inorganic fine particles having a small resistance value is Y and the addition amount is X (however, the number of parts relative to 100 parts by weight of the toner base)
0.1 ≦ X ≦ 2.0
Y ≦ 2.6 × 10 ⁻³ X + 0.0048
Thus, the inorganic fine particles are externally added to the surface of the toner base particles so that 0.5 ≦ X ≦ 1.5. When the addition amount X is smaller than 0.1, no matter how small the particle size and the sharp particle size distribution are attached to the toner base particles, it is insufficient to leak the charge-up amount. On the other hand, when the addition amount X is smaller than 0.1, the fluidity of the toner cannot be ensured, and toner replenishment cannot be performed during continuous output of a high image area, and an abnormal image is generated. On the other hand, when the addition amount X is larger than 2.0, the inorganic fine particles are fused to the carrier surface after a long period of use (spent), the chargeability of the carrier is lowered, and sufficient toner charge cannot be obtained. An abnormal image such as toner scattering occurs.
Further, in the range of Y> 2.6 × 10 ⁻³ X + 0.0048, no matter how sharply the inorganic fine particles having a sharp particle size distribution are used, the amount of charge-up cannot be sufficiently leaked because the absolute amount on the toner base particle surface is insufficient.

  Of the external additives adhering to the surface of the toner base particles used in the present invention, the adhesion rate of inorganic fine particles, which are one of the external additives having a low resistance value, to the surface of the toner base particles is 65% to 95%. It is preferably 80% to 95%. If the adhesion rate is less than 65%, the inorganic fine particles are detached from the surface of the toner base particles due to long-term use, and the charge leakage point is reduced, so that the charge-up cannot be suppressed. On the other hand, a value larger than 95% means that the inorganic fine particles are actually embedded on the surface of the toner base particles, if not completely, leak points are insufficient, and charge-up cannot be suppressed. Further, fluidity as a toner cannot be ensured.

The adhesion rate is expressed by the following (formula IV).
(Formula IV) (M ₁ / M ₀ ) × 100 (%)
In the formula, M ₁ is the weight of inorganic fine particles adhering to the surface of the toner base particles after dispersing the toner containing the external additive in the surfactant aqueous solution and sonicating for 1 minute under the condition of a resonance frequency of 25 KHz, M ₀ is the weight of inorganic fine particles adhering to the surface of the toner base particles before the ultrasonic treatment.

  The degree of methanol hydrophobization of the inorganic fine particles, which are external additives attached to the surface of the toner base particles used in the present invention, is preferably 55% to 95%. If the degree of hydrophobicity of methanol is less than 55%, it is easily affected by moisture in a high-temperature and high-humidity environment, and charge-down occurs and abnormal images such as background stains and toner scattering occur. On the other hand, if it is greater than 95%, the hydrophobicity is too high, so that charge up occurs at low temperature and low humidity, and the function as a leak component is not exhibited.

  The average circularity of the toner base particles used in the present invention is preferably 0.910 to 0.970. More preferably, it is 0.920-0.960. If the average circularity is less than 0.910, the contact probability between the external additive and the carrier is reduced and suitable for securing the leak point, but the contact point is limited, so the total charge amount is insufficient. End up. In addition, transferability is deteriorated, and image quality is deteriorated due to transfer residue. On the other hand, if it is greater than 0.970, the transferability is improved, but the contact probability between the external additive and the carrier is increased, so that the external additive is liberated or buried by long-term use, and the charge-up cannot be suppressed. In addition, it causes various problems such as poor fluidity.

The toner base particles used in the present invention have a charge performance by stirring with a carrier of charge amount Q ^B / M ₁₈₀ (−μC / g) when continuously stirred for 3 minutes and charge amount when continuously stirred for 60 minutes. The ratio of Q ^B / M ₃₆₀₀ (−μC / g) is 1.5 <[Q ^B / M ₃₆₀₀ ] / [Q ^B / M ₁₈₀ ] <2.5. [Q ^B / M ₃₆₀₀ ] / [Q ^B / M ₁₈₀ ] means the ratio of Q ^B / M ₁₈₀ and Q ^B / M ₃₆₀₀ (hereinafter the same). When only toner base particles not containing an external additive are stirred with a carrier, charging generally increases with increasing stirring time. However, when [Q ^B / M ₃₆₀₀ ] / [Q ^B / M ₁₈₀ ] is smaller than 1.5, Even if the inorganic fine particles according to the present invention are added, the charge becomes too low after long-term use, and abnormal images such as background stains and toner scattering occur. On the other hand, if it is larger than 2.5, even when the inorganic fine particles according to the present invention are added, the toner charge-up cannot be absorbed and an abnormal image such as a decrease in image density occurs.

In addition, the toner containing the external additive used in the present invention has a charge performance by stirring with a carrier of charge amount Q ^T / M ₁₈₀ (−μC / g) when continuously stirred for 3 minutes and continuous stirring for 60 minutes. The ratio of the charge amount Q ^T / M ₃₆₀₀ (−μC / g) is 0.7 <[Q ^T / M ₃₆₀₀ ] / [Q ^T / M ₁₈₀ ] <1.3. [Q ^T / M ₃₆₀₀ ] / [Q ^T / M ₁₈₀ ] means a ratio of Q ^T / M ₁₈₀ and Q ^T / M ₃₆₀₀ (hereinafter the same). If it is smaller than 0.7, the charge is lowered too much after a long period of use, and abnormal images such as background stains and toner scattering occur. On the other hand, if the ratio is larger than 1.3, the toner charge-up cannot be absorbed as in the above case, and an abnormal image such as a decrease in image density occurs.

The image forming method of the present invention includes a charging step in which a voltage is applied to a charging unit to charge a charged body, an exposure step in which an electrostatic latent image is formed on the charged charged body, and the electrostatic latent image is developed with toner. Development process for forming a toner image on a charged body, a transfer process for transferring the toner image on the charged body to a transfer material with or without an intermediate transfer member, and a toner image on the transfer material An image forming method including a fixing step of heat-fixing, wherein the developing step includes an agitating / conveying means for conveying the developer while stirring and charging, and the agitating / conveying step includes at least stirring the developer and The relationship among the rotation speed α (rotation / min), pitch β (mm), and conveyance path length γ (mm) of the agitating / conveying means (excluding the developing means) to be conveyed is 1.0 × 10 ⁶ ≦ α × β × γ ≦ 16.0 × 10 ⁶ . If α × β × γ is smaller than 1.0 × 10 ⁶ , the charging will be excessively lowered due to long-term use, and abnormal images such as background stains and toner scattering occur, whereas if it is larger than 16.0 × 10 ⁶ , the toner An abnormal image such as a decrease in image density occurs due to insufficient charge up.
Here, the rotation speed α means that the developer is agitated and transported in the developer container in the stage before supplying the developer to the developing roller in a developing unit of a commonly used known image forming apparatus. The rotation speed of the screw, the pitch β is the pitch of the screw, and the conveyance path length γ is the moving distance until the toner replenished from the toner cartridge reaches the developing roller.

  As the binder resin used in the present invention, a polyol resin is used from the viewpoint of obtaining a high image gloss of a full-color image, good color developability, and a wide fixing temperature range. As the polyol resin, from the viewpoints of environmental stability of charging, fixing stability, color reproducibility, gloss stability, anti-curling property after fixing, etc., the end of the epoxy resin is capped and the polyoxyalkylene moiety is in the main chain. Those having the are preferred. For example, it can be obtained by reacting an epoxy resin having a glycidyl group at both ends and an alkylene oxide adduct of a dihydric phenol having both glycidyl groups with a dihalide, isocyanate, diamine, diol, polyhydric phenol, or dicarboxylic acid. Of these, it is most preferable to react divalent phenol in terms of reaction stability. Moreover, it is also preferable to use polyhydric phenols and polyhydric carboxylic acids in combination with dihydric phenols as long as they do not gel.

  The polyol resin used in the present invention preferably has a molecular chain in which the ratio EX / OH of the epoxy group (EX) to the OH group (OH) is 0.990 to 1.010. When EX / OH is less than 0.990, since many OH groups are present in the molecular chain, the toner charge is likely to be absorbed under high humidity, and the toner charge level is reduced, resulting in abnormal images such as background stains and toner scattering. . On the other hand, when it is larger than 1.010, the reaction stability is deteriorated and the performance of the polyol resin cannot be sufficiently exhibited.

  As the colorant, all known dyes and pigments can be used. Examples of yellow include naphthol yellow S, hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, ocher, yellow lead, titanium. 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 Examples of yellow lake, anslagen yellow BGL, isoindolinone yellow, magenta toner include Resor Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmine BS, Permanent Red (E2R, F4R, FRL, FRLL, F4RH), Fast Carlet VD, Belcan Fast Rubin B, Brilliant Scarlet G, Resol Rubin GX, Permanent Red F5R, Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Toluidine Marine, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Marine Light, Bon Marine Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thioindigo Red B, Thioindigo Maroon, Oil Red, Quinacridone Red, Pyrazolone Red, Chrome Vermilion, Benzidine Orange, Perinone Orange, Oil Orange, Cyan Examples of toners include cobalt blue, cerulean blue, alkaline blue rake, peacock blue rake, Cutria 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, di Oxazine Violet, Anthraquinone Violet, Chrome Green, Zinc Green, Chrome Oxide, Pyridian Emerald Green, Pigment Green B, Naphthol Green B, Green Gold, Acid Green Lake, Malachite Green Lake, Phthalocyanine Green, Anthraquinone Green, Titanium Oxide, Zinc Hana , Lithbon and mixtures thereof, examples for black toner are carbon black, nigrosine dye, iron black, and cyan as complementary color System pigments, and the like. The amount used is generally 0.1 to 50 parts by weight per 100 parts by weight of the binder resin for each color.

  The toner used in the present invention may contain a charge control agent as necessary. All 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). Quaternary ammonium salts), alkylamides, phosphorus simple substances or compounds, tungsten simple substances or compounds, fluorine-based activators, salicylic acid metal salts, and metal salts of salicylic acid derivatives. The amount of charge control agent used is determined by the toner production method, such as the type and amount of the binder resin and additive, and is not uniquely limited, but is preferably 0 with respect to 100 parts by weight of the binder resin. Used in the range of 1 to 10 parts by weight. The range of 0.5 to 3 parts by weight is preferable. If the amount is less than 0.1 parts by weight, the toner is not practically negatively charged. When the amount exceeds 10 parts by weight, the chargeability of the toner is too high, and the density of the image is lowered due to spent or filming due to an increase in electrostatic attraction force with the carrier or the developing sleeve. Moreover, you may use a some charge control agent together as needed. Further, the addition amount may be changed depending on the developing order of each color toner.

  The toner used in the present invention may contain a wax as necessary. The melting point of the wax is 40 to 120 ° C, and 50 to 110 ° C is particularly preferable. When the melting point of the wax exceeds 120 ° C., fixability at a low temperature may be insufficient, while when the melting point is less than 40 ° C., offset resistance and durability may be deteriorated. The melting point of the wax can be obtained by differential scanning calorimetry (DSC). That is, the melting peak value when a sample of several mg is ripened at a constant temperature increase rate, for example, (10 ° C./min) is defined as the melting point. Examples of the wax include solid paraffin wax, micro wax, rice wax, fatty acid amide wax, fatty acid wax, aliphatic monoketone, fatty acid metal salt wax, fatty acid ester wax, partially saponified fatty acid ester wax, and silicone. Mention may be made of varnishes, higher alcohols and carnauba wax. Also, polyolefins such as low molecular weight polyethylene and polypropylene can be used. Particularly, a polyolefin having a softening point of 70 to 150 ° C. by the ring and ball method is preferable, and a polyolefin having a softening point of 120 to 150 ° C. is more preferable.

  Examples of the carrier for the two-component developer include conventional ones such as iron powder, ferrite, magnetite, and glass beads. These carriers may be those coated with resin. Examples of the resin include polyvinyl fluoride, polyvinyl chloride, polyvinylidene chloride, phenol resin, polyvinyl acetal, and silicone resin. In any case, the mixing ratio of toner and carrier is generally about 1.5 to 10.0 parts by weight of toner with respect to 100 parts by weight of carrier.

  Examples of the external additive used in the present invention include inorganic fine particles such as metal oxide, metal carbide, metal nitride, and metal carbonate. Specifically, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, 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 the like. Furthermore, organic fine particles can be used as the external additive. Specifically, polymer fine particles, for example, polystyrene obtained by soap-free emulsion polymerization, suspension polymerization, dispersion polymerization; methacrylate ester; acrylate ester copolymer; silicone; benzoguanamine; polycondensation system such as nylon; Polymer particles made of a thermosetting resin may be used.

In addition, the external additive used in the present invention can prevent the deterioration of the flow characteristics and charging characteristics even under high humidity by performing surface treatment to increase hydrophobicity. Preferred surface treatment agents used for the surface treatment include, for example, coupling agents such as silane coupling agents, titanate coupling agents, and aluminum coupling agents that may contain alkyl groups, fluorinated alkyl groups, silicone oils, and higher grades. Examples include fatty acids and fluorine compounds.
In particular, a silane coupling agent which is an example of a coupling agent is used for the purpose of improving the degree of hydrophobicity and fluidity. Specifically, as the silane coupling agent, chlorosilane, alkoxysilane, silazane, special silylating agent and the like can be used, and among them, alkoxysilane is preferable. Examples of the alkoxysilane include vinyltrimethoxysilane, propyltrimethoxysilane, i-butyltrimethoxysilane, n-butyltrimethoxysilane, n-hexyltrimethoxysilane, n-octyltrimethoxysilane, and n-dodecyltrimethoxy. A silane etc. can be mentioned.
As the silicone oil, polydimethylsiloxane, polymethylphenylsiloxane, polydiphenylsiloxane and the like can be used. As the silicone oil, siloxane containing fluorine may be used.
The fluorine compound is preferably an organosilicon compound having a fluorine atom, such as 3,3,4,4,5,5,6,6,6-nonafluorohexyltrichlorosilane, 3,3,3-trifluoropropyl. Trimethoxysilane, methyl-3,3,3-trifluoropropyldichlorosilane, dimethoxymethyl-3,3,3-trifluoropropylsilane, 3,3,4,4,5,5,6,6,6- Nonafluorohexylmethyldichlorosilane and the like can be mentioned.
Examples of higher fatty acids include stearic acid, oleic acid, palmitic acid, and linoleic acid. Further, as the higher fatty acid, these metal salts can be used. Specifically, zinc stearate, aluminum stearate, copper stearate, magnesium stearate, calcium stearate, zinc oleate, manganese oleate, palmitic acid Examples include zinc acid, zinc linoleate, and calcium linoleate.
In the present invention, it is preferable that the inorganic fine particles which are one external additive having a small resistance value are titanium oxide subjected to a hydrophobic treatment.

  The external additive used in the present invention preferably has an average primary particle size of 0.005 μm to 0.03 μm, and more preferably 0.01 μm to 0.02 μm. When the average primary particle size is smaller than 0.005 μm, when the external additive and the toner base particles are mixed with a mixer or the like, the external additive may fly and adhere to the mixer wall surface. The external additive cannot sufficiently adhere to the surface of the toner base. On the other hand, if it is larger than 0.03 μm, it is necessary to increase the amount of prescription in order to ensure the same fluidity and leak point as those having a small particle size, which causes problems such as carrier spent.

  The total amount of external additives used in the present invention is preferably 0.5 to 3.5% by weight based on the weight of the toner base particles.

Next, a toner manufacturing method will be described.
The toner used in the present invention is produced, for example, by sequentially performing a mechanical mixing process, a melt-kneading process, a pulverizing process, and a classification process with a toner composition containing a binder resin, a colorant, and a charge control agent. In the above-described mechanical mixing step, the toner used in the present invention may be mechanically mixed again as a toner composition with a predetermined outer particle size component obtained in the pulverization step and / or classification step. Of course, you may manufacture without adding a predetermined outer particle size component. When a predetermined outer particle size component is mechanically mixed again as a toner composition for production, the used amount of the predetermined outer particle size component is 5 to 40 with respect to 100 parts by weight of the toner composition excluding the predetermined outer particle size component. It is preferable that it is a ratio of a weight part, More preferably, it is 10-35 weight part. The predetermined outer particle size component becomes relatively brittle when kneading is repeated twice, and this can be used to improve the pulverization property. Therefore, if the amount is less than 5 parts by weight, this effect is weakened. On the other hand, if it exceeds 40 parts by weight, there will be problems with storage stability and durability.
In the method for producing the toner used in the present invention, the mixing step of mechanically mixing the binder resin, the colorant, the charge control agent and the predetermined outer particle diameter component is usually performed using a normal mixer using rotating blades. There are no particular restrictions.
After the above mixing step is completed, the mixture is then charged into a kneader and melt-kneaded. As the melt kneader, a uniaxial or biaxial continuous kneader or a batch kneader using a roll mill can be used. It is important that this melt-kneading is performed under appropriate conditions so as not to break the molecular chain of the binder resin. Specifically, it is preferable to melt knead in the range of 40 ° C to 65 ° C. When the melt kneading temperature is lower than 40 ° C, cutting is severe, and when it is higher than 65 ° C, dispersion does not proceed.
After the above melt-kneading process is completed, the kneaded product is then pulverized. In this pulverization step, it is preferable to first coarsely pulverize and then finely pulverize. At this time, a method of pulverizing by colliding with a collision plate in a jet stream, a method of pulverizing with a narrow gap between a rotating rotor that rotates mechanically and a stator are preferably used.
After the above pulverization step is completed, the pulverized product is classified in an air stream by centrifugal force or the like to produce toner base particles having a predetermined particle size, for example, a weight average particle size of 5 to 12 μm. At this time, it is particularly preferable that the toner has a weight average particle diameter of 5 to 9 μm, a small particle diameter such that 10% by number or less of toner particles having a particle diameter of 4 μm or less are present, and a sharp particle size distribution. In addition, the predetermined outer particle size component obtained in the pulverization step and / or the classification step is used by returning to the mixing step as a reused portion.
To the toner base particles obtained through the above steps, inorganic fine particles such as hydrophobic silica and hydrophobic titanium oxide are added and mixed. For mixing external additives, a general powder mixer is used. It is preferable to equip the mixer with a jacket or the like to adjust the internal temperature. In order to change the adhesion rate (adhesion strength) of the external additive on the surface of the toner base particles, the additive may be added midway or gradually. Of course, the rotation speed, time, temperature, etc. of the mixer may be changed. For example, a strong load may be given first, and then a relatively weak load, or vice versa. Examples of the mixer that can be used include a V-type mixer, a rocking mixer, a lady gay mixer, a nauter mixer, and a Henschel mixer.

<Measurement of resistance value of external additive>
As a device for measuring the dielectric loss of the external additive, a TR-10C type dielectric loss measuring device (Ando Electric Co., Ltd.) can be used. First, 5.0 to 5.1 g of the external additive is weighed, a 6 t / cm ² load is applied for 1 minute, and the sample is molded into a disk shape having a diameter of 40 mm and a thickness of 2.2 to 2.5 mm to obtain a measurement sample. . This sample is fixed to a jig and measured at room temperature (25 ° C.). The frequency is 1 KHz and the ratio is 1 × 10 ⁻⁹ . Log (R) is obtained from the conductance (R) obtained by measurement, and this can be used as the resistance value of the external additive.
In addition, in the inorganic fine particles having two different resistance values used in the present invention, the difference between the resistance values of these inorganic fine particles is preferably 1.0 × 10 ^{3 to} 1.0 × 10 ⁶ (log Ω × cm).

<Particle size distribution of external additive>
As a device for measuring the particle size distribution of the external additive, a laser diffraction particle size distribution measuring system LA-920 (manufactured by Horiba, Ltd.) can be used. 0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 ml of the electrolytic aqueous solution. Here, the electrolytic solution is a solution prepared by preparing a 1% by mass NaCl aqueous solution using primary sodium chloride. For example, ISOTON-II (manufactured by Coulter) can be used. To this, 0.1 to 0.3 mg of an external additive is further added. The electrolytic solution in which the external additive is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, the frequency distribution is calculated by the measuring device, and the arithmetic dispersion Y indicating the extent of the distribution from the following calculation formula: Can be requested.
Arithmetic dispersion Y = Σ [(X (J) −Mean) ² × q (J) / 100] (μm ² )
J: Particle size division number q (J); Frequency distribution value (%)
X (J): representative value of the J-th particle size range (μm)
Mean: arithmetic mean diameter (μm)

<Adhesion rate of external additives>
The adhesion rate of the external additive to the toner base particle surface is measured as follows. 5 g of the toner with the external additive attached thereto was soaked in 100 ml of a 0.2 wt% aqueous solution of a surfactant (surfactant (trade name: drywell) manufactured by Fuji Film Co., Ltd .; 33 wt%), and then ultrasonicated. Inorganic ultrasonic particles are detached from the surface of the toner base particles by immersing an ultrasonic vibrator in the dispersion using a type homogenizer (UH-30 manufactured by Ultrasonic Industry Co., Ltd.) and oscillating ultrasonically for 1 minute at a resonance frequency of 25 KHz. Let Thereafter, the dispersion is washed, filtered with suction, and dried. 3.0 to 3.1 g of the dried toner is weighed, and a 6 t / cm ² load is applied for 1 minute to form a disk shape having a diameter of 40 mm and a thickness of 2.2 to 2.5 mm. The inorganic fine particles remaining on the surface of the toner particles are quantified. The quantitative value and _{M 1.} By the sonication molded similarly the toner is not carried out X-ray fluorescence analysis to quantitate the inorganic fine particles present on toner particle surfaces, and this value as M _0. The adhesion rate of the external additive can be determined from the following calculation formula.
Adhesion rate of external additive = (M ₁ / M ₀ ) × 100 (%)

<Methanol hydrophobization degree of external additive>
The degree of methanol hydrophobization of the external additive is as follows. Weigh out 0.1 g of external additive in a 200 ml beaker, add 50 ml of ion-exchanged water dyed with edible blue No. 1, and stir with a magnetic stirrer. About 2 ml of methanol is dropped every 10 seconds by a burette, and the state in which the external additive floating on the liquid surface is completely wetted is the end point, and the degree of methanol hydrophobization can be determined from the following equation.
Hydrophobic degree of external additive methanol = titration / (titration +50) x 100 (%)

<Average circularity of toner base particles>
The average circularity of the toner base particles is an average circularity measured by an image analysis method, and is preferably a value measured using a flow type particle image analyzer FPIA-2100 manufactured by Sysmex Corporation.
After calculating the circularity of each particle, the analyzer “FPIA-2100” assigns each particle to 61 divided classes having a circularity of 0.4 to 1.0, and uses the center value and frequency of the dividing points. A calculation method (division method) for calculating the average circularity is used. The error of the average circularity calculated by the calculation method using the value of the average circularity calculated by this calculation method and the total circularity of each particle (summation method) is very small and can be substantially ignored. Degree. In the calculation of the average circularity of the toner base particles in the present invention, a summation method may be used, but for reasons of data handling such as shortening the calculation time and simplifying the calculation formula, the division method is used. Also good. Furthermore, “FPIA-2100”, which can be used to measure the average circularity of the toner base particles of the present invention, is thinner in sheath flow than “FPIA1000” conventionally used for calculating the shape of the toner. Since the accuracy of toner shape measurement is improved by layering (7 μm → 4 μm), improving the magnification of the processed particle image, and further improving the processing resolution of the captured image (256 × 256 → 512 × 512), Fine particles can be captured more reliably. Therefore, in calculating the average circularity of the toner base particles, it is preferable to use “FPIA-2100” which can more accurately obtain information on the shape and particle size distribution. As a specific measurement method, analysis is performed with the above-described analyzer in an environment of 23 ° C. and 60% RH, and a projected image of particles within a circle equivalent diameter range of 0.60 μm to 400 μm is analyzed. The length L is measured. From the measured perimeter, the circularity of the particles is determined by the following formula. Further, for the particles having a circle-equivalent system in the range of 3 μm to 400 μm, the total circularity of the particles and the number of the particles are obtained. Then, a value obtained by dividing the sum of the circularity by the number of particles is defined as an average circularity.
Circularity = L0 / L
[In the formula, L0 indicates the circumference of a circle having the same projection area as the particle image, and L is a particle projection image when image processing is performed at an image processing resolution of 512 × 512 (pixels of 0.3 μm × 0.3 μm). The perimeter of is shown. ]
The detailed measurement procedure is described below. A surfactant (preferably alkylbenzene sulfonate) (0.1 to 0.5 ml) is added as a dispersant to water (200 to 300 ml) in a container from which impurities have been removed in advance, and a measurement sample is further added to 0.1%. Add ~ 0.5g. The suspension in which the sample is dispersed is dispersed with an ultrasonic oscillator for 2 minutes, so that the concentration of the dispersion is 0.2 to 1 million pieces / μl. For example, the following apparatus is used as the ultrasonic oscillator, and the following dispersion conditions are used.
UH-150 (manufactured by SMT Corporation)
OUTPUT level: 5
Constant mode The circularity distribution of the particles of the dispersion obtained above is measured. An outline of the measurement will be described below.
The sample dispersion is passed through a flow path (expanding along the flow direction) of a flat and flat flow cell (thickness: about 200 μm). The strobe and the CCD camera are mounted on the flow cell so as to be opposite to each other so as to form an optical path that passes through the thickness of the flow cell. While the sample dispersion is flowing through the flow cell, strobe light is irradiated at 1/30 second intervals to obtain an image of particles dispersed in the sample dispersion. As a result, each particle is photographed as a two-dimensional image having a certain range parallel to the flow cell. From the area of the two-dimensional image of each particle, the diameter of a circle having the same area is calculated as the equivalent circle diameter. From the projected area of the two-dimensional image of each particle and the perimeter of the projected image, the circularity of each particle is calculated using the above circularity calculation formula. From the calculated circularity, the average circularity can be obtained as described above.

<Toner base particle charge amount Q ^B / M and toner particle charge amount Q ^T / M>
The charge amount of the toner base particles and the toner particles is measured as follows. 3 g of the developer having toner base particles or toner particles and a carrier prepared therein is placed in a cylindrical stainless steel container having a diameter of 2.5 cm and a height of 3.0 cm, and stirred for 3 minutes with a ball mill at a speed of 250 rpm. The toner concentration (TC) in the developer at this time is 3 to 7% by weight. The toner charge amount in the developer is measured using a horizontal blow measuring device. The obtained charge amount is defined as Q ^B / M ₁₈₀ or Q ^T / M ₁₈₀ . Similarly, the charge amount obtained by stirring for 60 minutes is defined as Q ^B / M ₃₆₀₀ or Q ^T / M ₃₆₀₀ .

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but this is not intended to limit the scope of the present invention. In the following, “parts” indicating the blending amount of the mixture and the like are all parts by weight.

(Synthesis example of polyol resin)
Synthesis example 1
To a separable flask equipped with a stirrer, a thermometer, an N ₂ inlet and a cooling tube, 1000 g of low-molecular bisphenol A type epoxy resin (number average molecular weight: about 1000), 50 g of terephthalic acid, 10 g of benzoic acid, and 300 g of xylene are added. It was. The temperature was raised to 70-100 ° C. in an N ₂ atmosphere, 0.183 g of lithium chloride was added, the temperature was further raised to 160 ° C., xylene was distilled off under reduced pressure, and polymerization was performed at a reaction temperature of 180 ° C. for 6-9 hours. As a result, about 1 kg of a polyol resin having a softening point of 108 ° C. and a Tg of 61 ° C. was obtained (hereinafter referred to as “resin 1”). The ratio EX / OH between the epoxy group (EX) and the OH group (OH) was 0.995.

Synthesis example 2
Using the apparatus of Synthesis Example 1, 500 g of low molecular weight bisphenol A type epoxy resin (number average molecular weight: about 1000), 404 g of high molecular weight bisphenol A type epoxy resin (number average molecular weight: about 50000), 103 g of bisphenol A, p-cumyl A separable flask was charged with 59 g of phenol and 300 g of xylene. The temperature was raised to 70-100 ° C. in an N ₂ atmosphere, 0.183 g of lithium chloride was added, the temperature was further raised to 160 ° C., and xylene was distilled off under reduced pressure, and the reaction temperature was 180 ° C. for 6-9 hours. Polymerization was performed to obtain 1000 g of a polyol resin having a softening point of 109 ° C. and a Tg of 58 ° C. (hereinafter referred to as “resin 2”). The ratio EX / OH between the epoxy group (EX) and the OH group (OH) was 1.000.

Synthesis example 3
Using the apparatus of Synthesis Example 1, 302 g of low molecular weight bisphenol A type epoxy resin (number average molecular weight: about 360), 100 g of high molecular weight bisphenol A type epoxy resin (number average molecular weight: about 3000), bisphenol A type ethylene oxide adduct 336.0 g of diglycidylated product [n + m: about 5.9 in the above general formula (3)], 210 g of bisphenol A, 100 g of p-cumylphenol, and 300 g of xylene were charged into a separable flask. The temperature was raised to 70-100 ° C. in an N ₂ atmosphere, 0.183 g of lithium chloride was added, the temperature was further raised to 160 ° C., and xylene was distilled off under reduced pressure, and the reaction temperature was 180 ° C. for 6-9 hours. Polymerization was performed to obtain about 1 kg of a polyol resin having a softening point of 109 ° C. and a Tg of 58 ° C. (hereinafter referred to as “resin 3”). The ratio EX / OH between the epoxy group (EX) and the OH group (OH) was 1.005.

Synthesis example 4
Using the apparatus of Synthesis Example 1, 390 g of low molecular weight bisphenol A type epoxy resin (number average molecular weight: about 680), 403 g of high molecular weight bisphenol A type epoxy resin (number average molecular weight: about 6500), bisphenol A type propylene oxide adduct And 199 g of divalent acid of phthalic anhydride condensation, 50 g of bisphenol A, 51 g of p-cumylphenol, and 300 g of xylene were charged into a separable flask. The temperature was raised to 70-100 ° C. in an N ₂ atmosphere, 0.183 g of lithium chloride was added, the temperature was further raised to 160 ° C., and xylene was distilled off under reduced pressure, and the reaction temperature was 180 ° C. for 6-9 hours. Polymerization was performed to obtain about 1 kg of a polyol resin having a softening point of 112 ° C. and a Tg of 59 ° C. (hereinafter referred to as “resin 4”). The ratio EX / OH between the epoxy group (EX) and the OH group (OH) was 1.015.

(Example of toner base particle production)
Production Example 1
Raw material composition Binder resin: Resin 1 ... 100 parts Colorant: Cyan pigment (copper phthalocyanine) ... 5 parts Charge control agent: Bontron E-84 (manufactured by Orient Chemical Industries) ... 2 parts After mixing using a Henschel mixer (manufactured by Mitsui Miike Co., Ltd.), kneading was performed for 30 minutes with two rolls whose roll surface was set to 60 ° C. Then, after rolling and cooling and coarse pulverization, a jet mill type pulverizer (I-2 type mill: manufactured by Nippon Pneumatic Industry Co., Ltd.) and a wind classifier (DS classifier: manufactured by Nippon Pneumatic Industry Co., Ltd.) are used. Toner base particles were obtained. The triboelectric charge amount [Q ^B / M ₃₆₀₀ ] / [Q ^B / M ₁₈₀ ] with the carrier (hereinafter referred to as “base 1”) was 2.3, and the average circularity was 0.925.

Production Example 2 to Production Example 4
Toner base particles were obtained by the same formulation and the same method as in Production Example 1 except that the binder resin in Production Example 1 was changed to “Resin 2” to “Resin 4” in Synthesis Examples 2 to 4. The friction charge amounts [Q ^B / M ₃₆₀₀ ] / [Q ^B / M ₁₈₀ ] with the carrier (hereinafter referred to as “base 2 to base 4”) are 1.9 for “base 2” and 1.6 for “base 3”. "Mother 4" was 1.2. The average circularity was 0.932 for “matrix 2”, 0.928 for “matrix 3”, and 0.936 for “matrix 4”.

Production Example 5
Except that the binder resin was changed to a polyester resin in Production Example 1, toner base particles were obtained by the same formulation and the same method as Production Example 1 (hereinafter referred to as “matrix 5”). The polyester resin is a resin obtained by condensation polymerization of bisphenol A ethylene oxide adduct, bisphenol A propylene oxide adduct, terephthalic acid and fumaric acid in a molar ratio of 60: 40: 25: 75, and has a softening point of 107 ° C., Tg is 59 ° C. The triboelectric charge amount [Q ^B / M ₃₆₀₀ ] / [Q ^B / M ₁₈₀ ] with the carrier was 2.1, and the average circularity was 0.941.

<Example 1>
For 100 parts of “base 1”, 1.2 parts of hydrophobic silica (HDK2000H: manufactured by Clariant Japan, methanol hydrophobization degree: 70%) as an external additive, titanium oxide (JMT-150IB: manufactured by Teika Co., Ltd., particle size) 0.9 part of distribution Y: 0.005, methanol hydrophobization degree: 65%) was added and mixed with a Henschel mixer to obtain toner particles. The triboelectric charge amount [Q ^T / M ₃₆₀₀ ] / [Q ^T / M ₁₈₀ ] with the carrier (hereinafter referred to as “toner 1”) was 1.0, and the adhesion rate of titanium oxide was 80%. The obtained toner was evaluated as follows.

<Example 2> to <Example 6>, <Comparative Example 1> to <Comparative Example 7>
In Example 1, toners 2 to 13 were prepared in the same manner as in Example 1 except that the toner base particles and additives shown in Table 1 were used. However, in Example 6, the circumferential speed of the stirring blade was 1.2 times the circumferential speed in Example 1 and 0.8 times in Comparative Example 2 when mixing with a Henschel mixer.
In addition, the following were used as an additive. The toner obtained as described above was evaluated as follows.
Hydrophobic silica (HDK2000H: manufactured by Clariant Japan, methanol hydrophobization degree: 70%, resistance value 1.0 × 10 ¹² )
Titanium oxide (JMT-150IB: manufactured by Teica, particle size distribution Y; 0.005, methanol hydrophobization degree: 65%, resistance value 1.0 × 10 ⁸ )
Titanium oxide (MT-150AI: manufactured by Teica, particle size distribution Y; 0.010, methanol hydrophobization degree: 65%, resistance value 1.2 × 10 ⁸ )

Image quality evaluation (room temperature environment)
The container rolls at a ratio of 5 parts of toner and 100 parts of carrier of the toner obtained in Examples and Comparative Examples and a ferrite carrier having an average particle diameter of 50 μm coated with a silicone resin with an average thickness of 0.3 μm. The developer was prepared by uniformly mixing and charging using a tumbler mixer of the type stirred. This developer was subjected to a copy test using a digital full-color multifunctional machine “Imagio Neo C600” modified by Ricoh Co., Ltd., and the following items were evaluated. The copy test was conducted in 100,000 full color mode. As for the image quality of the obtained image, background stain and image density were evaluated. In addition, the number of rotations α (rotation / min) specified in the present invention is 600, the pitch β (mm) is 10, and the conveyance path length γ (mm) of the remodeled digital full-color MFP “Imagio Neo C600” manufactured by Ricoh Co., Ltd. Was 700, and α × β × γ was 4.2 × 10 ⁶ .
In each item, an image chart having a 3% image area was continuously run up to 100,000 sheets, and the following evaluation was performed.
(1) Background stain The blank image is stopped during development, the developer on the photoconductor after development is transferred to tape, and the difference from the image density of the untransferred tape is determined by 938 Spectrodensitometer (manufactured by X-Rite) ).
(2) Image density The image IDs of the left and right and central patch portions of the image chart having a 3% image area were measured with a 938 spectrodensitometer (manufactured by X-Rite), and the average value was obtained.

Image quality evaluation (high temperature and high humidity environment, low temperature and low humidity environment)
The evaluation was the same as the room temperature environment described above except that the evaluation environment was high temperature and high humidity (temperature 30 ° C./90% relative humidity) and low temperature and low humidity environment (temperature 10 ° C./15% relative humidity). The evaluation was performed after the evaluation machine was left in the above environment for 24 hours in advance.
The above evaluation results are shown in Table 2.

  In the examples of the present invention, superior image quality was obtained as compared with the comparative example.

  The present invention provides an image forming method and an electrostatic charge image developing toner capable of simultaneously solving a charge-up with a continuous output for a long time and a charge-down in a high-temperature and high-humidity environment, and is useful for an ultra-high-speed image forming apparatus. is there.

Claims (10)

In the image forming method having at least a charging step, an exposure step, a development step, a transfer step, and a fixing step, the developer used in the development step is at least a ratio EX / epoxy group (EX) to OH group (OH). A two-component developer comprising a toner containing, as a binder resin, a polyol-based resin having a plurality of OH groups in a molecular chain having an OH of 0.990 to 1.010, and a carrier, wherein the developing step includes at least the step A stirring / conveying step of conveying the developer while stirring and charging, wherein the stirring / conveying step includes at least a rotation speed α (rotation / conveyance) of a stirring / conveying means (excluding the developing means) for stirring and conveying the developer; min), a pitch beta (mm), the relationship of the conveying path length gamma (mm) is ^{1.0 × 10 6 ≦ α × β} × γ ≦ 16.0 × 10 6, the toner is the toner base particle And is composed of an outer additive, the toner base particles, the charging performance due to stirring of the carrier, the charge amount at the time of continuous stirring 3 min _{^{Q B / M 180 (-μC /}} g), 60 consecutive minutes As a ratio of charge amount Q ^B / M ₃₆₀₀ (−μC / g) when stirring, (Formula I),
(Formula I) 1.5 <[Q ^B / M ₃₆₀₀ ] / [Q ^B / M ₁₈₀ ] <2.5
The toner containing the external additive has a charge performance by stirring with the carrier of charge amount Q ^T / M ₁₈₀ (−μC / g) when stirring continuously for 3 minutes and charging when stirring continuously for 60 minutes. As a ratio of the quantity Q ^T / M ₃₆₀₀ (−μC / g), (Formula II)
(Formula II) 0.7 <[Q ^T / M ₃₆₀₀ ] / [Q ^T / M ₁₈₀ ] <1.3
The external additive includes at least two kinds of inorganic fine particles having different resistance values, and the particle size distribution Y and the addition amount X (however, the number of parts relative to 100 parts by weight of the toner base particles) of one external additive having a small resistance value are as follows: An image forming method characterized by satisfying the following (formula III):
(Formula III) 0.1 ≦ X ≦ 2.0
Y ≦ 2.6 × 10 ⁻³ X + 0.0048 2. The image forming method according to claim 1, wherein an adhesion rate represented by (Formula IV) of the inorganic fine particle which is one of the external additives having a small resistance value is 65% to 95%.
(Formula IV) (M ₁ / M ₀ ) × 100 (%)
M ₁ : the weight of inorganic fine particles adhering to the surface of the toner base particles after dispersing the toner containing the external additive in an aqueous surfactant solution and ultrasonically treating it for 1 minute under the condition of a resonance frequency of 25 KHz;
M ₀ : Weight of inorganic fine particles adhering to the surface of the toner base before ultrasonic treatment   The image forming method according to claim 1, wherein the toner base particles have an average circularity of 0.910 to 0.970.   4. The image forming method according to claim 1, wherein the inorganic fine particles which are external additives attached to the surface of the toner base particles have a methanol hydrophobization degree of 55% to 95%. .   5. The image forming method according to claim 1, wherein the inorganic fine particles as one external additive having a small resistance value are hydrophobized titanium oxide. 6. A toner including at least a polyol-based resin having a plurality of OH groups in a molecular chain having a ratio EX / OH of 0.990 to 1.010 of epoxy group (EX) and OH group (OH) as a binder resin; An electrostatic charge image developing toner used in a two-component developer comprising: toner base particles and external additives, wherein the toner base particles have a charging performance by stirring with the carrier. As a ratio of the charge amount Q ^B / M ₁₈₀ (−μC / g) when continuously stirred for 3 minutes and the charge amount Q ^B / M ₃₆₀₀ (−μC / g) when continuously stirred for 60 minutes, (Formula I ) And
(Formula I) 1.5 <[Q ^B / M ₃₆₀₀ ] / [Q ^B / M ₁₈₀ ] <2.5
The toner containing the external additive has a charge performance by stirring with the carrier of charge amount Q ^T / M ₁₈₀ (−μC / g) when stirring continuously for 3 minutes and charging when stirring continuously for 60 minutes. As a ratio of the quantity Q ^T / M ₃₆₀₀ (−μC / g), (Formula II)
(Formula II) 0.7 <[Q ^T / M ₃₆₀₀ ] / [Q ^T / M ₁₈₀ ] <1.3
The external additive includes at least two kinds of inorganic fine particles having different resistance values, and the particle size distribution Y and the addition amount X (however, the number of parts relative to 100 parts by weight of the toner base particles) of one external additive having a small resistance value are as follows: An electrostatic charge image developing toner satisfying the following (formula III):
(Formula III) 0.1 ≦ X ≦ 2.0
Y ≦ 2.6 × 10 ⁻³ X + 0.0048 The electrostatic charge image developing according to claim 6, wherein the adhesion ratio represented by (formula IV) of the inorganic fine particle which is one of the external additives having a small resistance value is 65% to 95%. toner.
(Formula IV) (M ₁ / M ₀ ) × 100 (%)
M ₁ : the weight of inorganic fine particles adhering to the surface of the toner base particles after dispersing the toner containing the external additive in an aqueous surfactant solution and ultrasonically treating it for 1 minute under the condition of a resonance frequency of 25 KHz;
M ₀ : Weight of inorganic fine particles adhering to the surface of the toner base before ultrasonic treatment   8. The toner for developing an electrostatic charge image according to claim 6, wherein the toner base particles have an average circularity of 0.910 to 0.970.   9. The electrostatic charge image according to claim 6, wherein the inorganic fine particles, which are external additives attached to the surface of the toner base particles, have a methanol hydrophobicity of 55% to 95%. Development toner.   The electrostatic image developing toner according to claim 6, wherein the inorganic fine particle as one of the external additives having a small resistance value is hydrophobized titanium oxide.