JP4708129B2 - Image forming toner, method for producing the same, developer, and image forming method and image forming apparatus using the same - Google Patents

Description

  The present invention relates to an image-forming toner capable of improving the low-temperature fixability, heat-resistant storage stability and offset resistance of the toner, and simultaneously improving the dispersibility and grindability of the toner composition during the production of the toner. The present invention relates to a method, a developer using the image forming toner, a toner container, an image forming method, an image forming apparatus, and a process cartridge.

In recent years, in order to save energy when fixing toner, it is required to reduce the fixing energy. Therefore, it is necessary to control the thermal characteristics of the toner itself, that is, the resin itself. However, lowering the Tg (glass transition temperature) of the resin causes deterioration in heat resistant storage stability and fixing strength, and if the F1 _{/ 2} temperature is lowered due to the lower molecular weight of the resin, the occurrence of hot offset and gloss are too high. Problems such as (gloss controllability) occur. For this reason, by controlling the thermal characteristics of the resin itself, it has not yet been possible to obtain a toner having excellent low-temperature fixability and excellent heat-resistant storage stability and offset resistance.

  In order to cope with such low-temperature fixing, attempts have been made to use polyester resins that are excellent in low-temperature fixing properties and relatively good in heat-resistant storage, in place of styrene-acrylic resins that have been widely used in the past (Patent Documents 1 to 3). 6: JP-A-60-90344, JP-A-64-15755, JP-A-2-82267, JP-A-3-229264, JP-A-3-41470, JP-A-11-305486 Publication). In addition, there is an attempt to add a specific non-olefinic crystalline polymer having a sharp melt property at a glass transition temperature to a binder for the purpose of improving low-temperature fixability (Patent Document 7: JP-A-62-63940). However, it cannot be said that the molecular structure and molecular weight are optimized.

  There are also attempts to use crystalline polyester having sharp melt properties (Patent Document 8: Japanese Patent No. 2931899, Patent Document 9: Japanese Patent Laid-Open No. 2001-222138). The acid value and the hydroxyl value of the resin are as low as 5 or less and 20 or less, respectively, and since the affinity between paper and crystalline polyester is low, sufficient low-temperature fixability cannot be obtained. In addition, the molecular structure and molecular weight of the crystalline polyester are not optimized, and furthermore, even with a fixing method in which a release oil is not applied to the fixing roller or an oil coating amount is very small while giving an appropriate gloss. It is not a toner that has sufficient low-temperature fixability and sufficient offset resistance, as well as excellent transferability, durability, charging stability against humidity, and pulverization. Even in Patent Document 9, there is sufficient low-temperature fixability and sufficient offset prevention even with a fixing method in which a release oil is not applied to the fixing roller or a very small amount of oil is applied while having an appropriate gloss. At the same time, the toner is not excellent in transferability, durability, charging stability with respect to humidity, and grindability.

  Further, in the technique described in Patent Document 10 (Japanese Patent Application Laid-Open No. 2002-214833), an incompatible and island-like phase separation structure between a crystalline polyester resin and an amorphous polyester resin, or a difference in THF insolubles in the resin. By specifying the maximum peak temperature that appears on the endothermic side in the DSC curve measured by a scanning calorimeter, both the lower limit of fixability and storage stability are achieved, but it cannot be said that sufficient quality has been obtained. There was found.

JP 60-90344 A JP-A 64-15755 Japanese Patent Laid-Open No. 2-82267 JP-A-3-229264 JP-A-3-41470 JP-A-11-305486 JP 62-63940 A Japanese Patent No. 2931899 JP 2001-222138 A JP 2002-214833 A

  The present invention has been made to solve the above-described problems, and improves the low-temperature fixability, heat-resistant storage stability and offset resistance of the toner, and dispersibility and grindability of the toner composition during toner production. An object of the present invention is to provide an image forming toner capable of achieving the improvement at the same time, a manufacturing method thereof, a developer, a toner container, an image forming method, an image forming apparatus, and a process cartridge using the image forming toner.

  As a result of intensive studies, the present inventors have found that the endothermic curve obtained by at least DSC measurement in a toner containing at least a binder resin, a colorant, and a release agent has a maximum endothermic peak in the temperature range of 40 to 75 ° C. After storing the toner in a constant temperature bath at 40 ° C. for 72 hours, the endothermic curve obtained by at least DSC measurement shows that the peak temperature of the maximum endothermic peak in the temperature range of 40 to 75 ° C. is B, It was found that the toner satisfying 5 ≦ B−A ≦ 13 gives good results for the above problems, and the present invention has been completed.

That is, the said subject is solved by (1)-(14) of this invention.
(1) “In a toner containing at least a binder resin, a colorant, and a release agent, the binder resin contains a crystalline polyester resin (A) and an amorphous polyester resin, The polyester resin (A) has a portion derived from 1,4-butanediol and a portion derived from fumaric acid, and the amorphous polyester resin is polyoxypropylene (2.2) -2,2-bis. (4-Hydroxyphenyl) propane-derived site, obtained by melt-kneading and pulverizing a toner composition containing the binder resin, and an endothermic curve obtained by DSC measurement in a temperature range of 40 to 75 ° C. the peak temperature of maximum endothermic peak as a, after the toner stored at 40 ° C. thermostatic chamber for 72 hours, the endothermic curve obtained by DSC measurement at a temperature from 40 to 75 The peak temperature of the maximum endothermic peak in the case of the B in the range of the image forming toner, which is a 5 ≦ B-A ≦ 13 "
(2) “Image forming toner according to item (1), wherein the content of the polyester resin (A) in the binder resin is 1 to 50% by weight”.
(3) “The softening temperature [T (F _1/2 )] of the polyester resin (A) is in the range of 80 to 130 ° C., and the glass transition temperature (Tg) is in the range of 80 to 130 ° C. The image forming toner according to item (1) or (2), characterized in that
(4) “Image forming toner according to any one of items (1) to (3), wherein the crystalline polyester resin (A) has an acid value of 20 to 45 mg KOH / g” "
(5) The image forming toner according to any one of (1) to (4), wherein the crystalline polyester resin (A) has a hydroxyl value of 5 to 50 mgKOH / g. "
(6) “Wax (C) is contained as the mold release agent, and the melting point of the wax (C) is 70 to 150 ° C. Any of the above items (1) to (5)” Image forming toner according to
(7) “The wax (C) is at least one of carnauba wax, polyethylene wax, and synthetic ester wax,” according to any one of (1) to (6), Image forming toner "
(8) “Toner composition containing at least a binder resin, a colorant, and a release agent is dry-mixed, melt-kneaded in a kneader, allowed to stand for 24 to 48 hours, pulverized, and if necessary The method for producing an image forming toner according to any one of (1) to (7), wherein classification is performed.
(9) "One-component developer comprising the image forming toner according to any one of (1) to (7)"
(10) “Two-component developer comprising the image forming toner according to any one of (1) to (7) and carrier powder”
(11) “Toner container filled with the developer according to item (9) or (10)”
(12) “The electrostatic latent image formed on the image carrier is developed with toner, the toner image formed on the image carrier is transferred to the image support, and the transferred toner image is transferred to a roller or belt. An image forming method including a step of obtaining a fixed image by heat-press fixing with a fixing member in the form of an image, wherein the developer according to item (9) or (10) is used. Formation Method "
(13) “Developing means for developing the electrostatic latent image formed on the image carrier with toner, transfer means for transferring the toner image formed on the image carrier to the image support, and transferring the transferred toner image In an image forming apparatus including a fixing unit that obtains a fixed image by heat and pressure fixing with a roller-shaped or belt-shaped fixing member, the developer described in the item (9) or (10) is loaded. Characteristic image forming apparatus "
(14) In the process cartridge that integrally supports a photosensitive member (image carrier) and a unit including at least a developing unit selected from a charging unit, a developing unit, and a cleaning unit, and is detachable from the main body of the image forming apparatus, The means holds the developer, and the developer is the developer described in the item (9) or (10).

According to the present invention, it is possible to provide an image forming toner excellent in low-temperature fixability, heat-resistant storage stability, and offset resistance.
In addition, according to the present invention, it is possible to provide a method for producing the toner, a developer using the toner, a toner container, an image forming method, an image forming apparatus, and a process cartridge.

The present invention is described in further detail below.
In the toner of the present invention, the peak temperature of the maximum endothermic peak in the temperature range of 40 to 75 ° C. of the endothermic curve obtained by DSC measurement after storing for 72 hours in a constant temperature bath at 40 ° C. is extremely important. This is because, when stored at 40 ° C., the change in the maximum endothermic peak temperature at which the toner is in this temperature range greatly affects the toner fixing lower limit and storage stability. The peak temperature reflects the thermal history that the toner has undergone during the manufacturing process, and after toner conversion, the peak temperature changes due to the influence of heat, and it has been confirmed that the fluctuation range contributes to fixability and storage stability. . Here, the normal temperature in the present invention means 24 ° C. unless otherwise specified.
When the peak temperature at the normal temperature of the toner is A and the peak temperature after the toner is stored in a constant temperature bath at 40 ° C. for 72 hours is B, 5 ≦ B−A ≦ 13. Can be achieved. In the case of the toner using the crystalline polyester resin (A), the present inventors have determined the “storage at 40 ° C. for 72 hours” based on restrictions on the storage and transportation environment of the toner.
Although the mechanism of the rising phenomenon of the toner endothermic peak due to the storage of the toner using the crystalline polyester (hereinafter referred to as C-Pes) is not clear, it is presumed as follows.
That is, after the toner is made by kneading and pulverization, a part of C-Pes is compatible with the amorphous resin and becomes amorphous. When the ratio of the compatible portion is large, the endothermic peak temperature as the toner is lowered (Tg is low) and the storage stability by heat is inferior, but the lower limit temperature at which the toner can be fixed is widened. Conversely, if C-Pes is less compatible with the amorphous resin, the toner has a higher endothermic peak and lower fixable lower temperature, but the storage stability is improved (since the Tg of crystalline C-Pes is around 110 ° C). If the ratio of the crystal state of C-Pes is large, the storage stability is good).
“B-A is greater than 13” means that C-Pes, which is compatible with storage of toner at 40 ° C., undergoes recrystallization (amorphous state → crystalline state), and if recrystallization proceeds, the endothermic peak of the toner The width of the rise is large. The large endothermic peak change width due to storage means that C-Pes before storage had many compatible parts with the amorphous resin. When there are many compatible parts, the Tg of the toner is lowered and the lower limit temperature for fixing is excellent, but the storage stability is poor.
On the other hand, “BA is smaller than 5” means that C-Pes before storage had few compatible parts with the amorphous resin. If the compatible part is small, the Tg of the toner is high and the minimum fixing temperature is poor, but the storage stability is excellent.
Such control of 5 ≦ B−A ≦ 13 is considered to be determined by the ratio of the compatible state with the amorphous resin of C-Pes. However, since there are places where crystallinity is difficult to measure, in the present invention, by using quality engineering techniques, the manufacturing conditions such as the ratio of toner prescription raw materials, the kneading step, the pulverizing step, and the additive mixing step are optimized. By making the prescription and manufacturing conditions that fall within 5 ≦ B−A ≦ 13 as optimum conditions, it is achieved intentionally and reliably. In other words, the technical key point of the present invention is that the optimum conditions for formulation and production are found in consideration of the balance of fixability, storage stability, and productivity. For example, if the C-Pes raw material ratio is large, the fixability is good, but the storage stability is poor. The recrystallization is promoted by adding a recrystallization aid to C-Pes at the time of polymerization. However, if the recrystallization is excessive, a filming problem occurs on the photoreceptor. This is a problem of balance, and it is preferable to determine an appropriate reference line in consideration of the recrystallization state, and such a reference line should be easily set by those skilled in the art.

  The toner preferably contains a crystalline polyester resin (A). It has been reported that the toner fixing lower limit is improved by containing the crystalline polyester, but the storage stability is inferior. Therefore, by controlling the thermal history of the toner until it is actually used and controlling the toner characteristic range described in the present invention, it is possible to more effectively achieve both the toner fixing lower limit temperature and the storage stability.

  In addition, the content of the polyester resin fine particles having crystallinity in the present invention needs to be 1 part by weight or more when the total amount of the binder resin is 100 parts by weight in order to express the effect on the low-temperature fixability. Desirably, it is 5 parts by weight or more. If this amount is large, the effect on fixing at low temperature is great, but if it is too large, the resin having crystallinity deteriorates the hot offset resistance. Therefore, it is preferably at most 50% by weight. More preferably, it is 30% by weight or less.

Further, since the melt viscosity of the resin having crystallinity rapidly decreases, the fixing lower limit temperature is controlled not only by the content thereof but also by the glass transition temperature (Tg) and the softening temperature (T (F _1/2 )). Is possible. In this invention, it is preferable that it is low in the range which does not deteriorate heat-resistant storage stability, Tg of the polyester resin which has crystallinity is the range of 80-130 degreeC, and T (F1 _{/ 2} ) is in the range of 80-130 degreeC. It is preferable. When Tg and T (F _1/2 ) are lower than the above ranges, it is difficult to synthesize a crystalline polyester that has sharp melt properties and easily exhibits an effect on low-temperature fixability. Since the minimum fixing temperature becomes high, the low temperature fixability cannot be obtained.

  The acid value of the crystalline polyester resin (A) is preferably 20 mgKOH / g or more in order to achieve the desired low-temperature fixability from the viewpoint of the affinity between paper and resin. On the other hand, in order to improve hot offset property, it is preferable that it is 45 mgKOH / g or less.

  Further, the hydroxyl value of the crystalline polyester resin (A) is preferably 5 to 50 mgKOH / g in order to achieve a predetermined low-temperature fixability and good charging characteristics.

  Moreover, it is preferable that melting | fusing point of the wax as a mold release agent is 70-150 degreeC. When the temperature is lower than 70 ° C., the heat resistant storage stability of the toner is poor. When the temperature is higher than 150 ° C., the releasability cannot be sufficiently achieved and the toner fixing property is poor.

  A conventionally known wax can be used as the release agent. For example, low molecular weight polyethylene wax, low molecular weight polyolefin wax such as polypropylene, synthetic hydrocarbon wax such as Fischer-Tropsch wax, natural wax such as beeswax, carnauba wax, candelilla wax, rice wax, montan wax, Examples include petroleum waxes such as paraffin wax and microcrystalline wax, higher fatty acids such as stearic acid, palmitic acid, and myristic acid, metal salts of higher fatty acids, higher fatty acid amides, synthetic ester waxes, and various modified waxes thereof.

Of these, carnauba wax and its modified wax, polyethylene wax, and synthetic ester wax are preferably used. In particular, the synthetic ester wax pentaerythritol tetrabehenate is most preferred. The reason for this is that carnauba wax and its modified wax and synthetic ester wax are appropriately finely dispersed with respect to the polyester resin and polyol resin, so that the toner has excellent offset prevention, transferability and durability as described later. This is because it is easy.
These waxes can be used alone or in combination of two or more. The amount of these release agents used is preferably 2 to 15% by weight based on the toner. If it is less than 2% by weight, the effect of preventing offset is insufficient, and if it exceeds 15% by weight, transferability and durability are deteriorated.

It was found that the control of the toner characteristics is greatly related not only to the selection and formulation of raw materials but also to the manufacturing conditions in the manufacturing process. In particular, precisely controlling manufacturing conditions and storage conditions in processes related to the thermal history of toner greatly affects toner characteristics.
For example, when a toner is produced by a kneading method, by changing the kneading temperature, feed, rolling thickness, cooling rate, time, etc., the toner has a maximum peak temperature change characteristic in the range of 40 to 75 ° C. by DSC. It is possible to control. For example, if the kneading temperature is too high, the previously melted polyester resin having crystallinity may act as a flux for the counterpart resin, but may separate and precipitate after cooling, and the cooling rate will be slow after kneading. If the amount is too large, the counterpart resin may separate and precipitate. The same applies when the feed amount is too large or the rolling thickness is too thick.

(Crystalline polyester A)
The crystalline polyester resin (A) used in the present invention comprises a crystalline aliphatic polyester resin containing at least 60 mol% of an ester bond represented by the following general formula (1) in its molecular main chain. And

（前記一般式（１）中、Ｒは直鎖状不飽和脂肪族２価カルボン酸残基を示し、炭素数２〜２０、好ましくは２〜４の直鎖状不飽和脂肪族基である。ｎは２〜２０、好ましくは２〜６の整数である。）
一般式（１）の構造の存在は固体Ｃ１３ＮＭＲにより確認することができる。
前記直鎖状不飽和脂肪族基の具体例としては、マレイン酸、フマル酸、１，３−ｎ−プロペンジカルボン酸、１，４−ｎ−ブテンジカルボン酸等の直鎖状不飽和２価カルボン酸由来の直鎖状不飽和脂肪族基を挙げることができる。

(In the general formula (1), R represents a linear unsaturated aliphatic divalent carboxylic acid residue, and is a linear unsaturated aliphatic group having 2 to 20 carbon atoms, preferably 2 to 4 carbon atoms. n is an integer of 2 to 20, preferably 2 to 6.)
The presence of the structure of the general formula (1) can be confirmed by solid C13 NMR.
Specific examples of the linear unsaturated aliphatic group include linear unsaturated divalent carboxylic acids such as maleic acid, fumaric acid, 1,3-n-propene dicarboxylic acid, and 1,4-n-butene dicarboxylic acid. Mention may be made of linear unsaturated aliphatic groups derived from acids.

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

The polyester resin (A) is a polyvalent carboxylic acid comprising (i) a linear unsaturated aliphatic divalent carboxylic acid or a reactive derivative thereof (an acid anhydride, a lower alkyl ester having 1 to 4 carbon atoms, an acid halide, etc.). It can be produced by subjecting an acid component and (ii) a polyhydric alcohol component composed of a linear aliphatic diol to a polycondensation reaction by a conventional method.
In this case, a small amount of other polyvalent carboxylic acid can be added to the polyvalent carboxylic acid component as necessary. The polyvalent carboxylic acid in this case includes (i) a saturated aliphatic divalent carboxylic acid having a branched chain, (ii) a saturated aliphatic divalent carboxylic acid, a saturated aliphatic trivalent carboxylic acid, and the like. In addition to polyvalent carboxylic acids, (iii) aromatic polyvalent carboxylic acids such as aromatic divalent carboxylic acids and aromatic trivalent carboxylic acids are included. The addition amount of these polyvalent carboxylic acids is usually 30 mol% or less, preferably 10 mol% or less, based on the total carboxylic acid, and is appropriately added within the range where the resulting polyester has crystallinity.

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

If necessary, a small amount of an aliphatic branched dihydric alcohol or cyclic dihydric alcohol, or a trihydric or higher polyhydric alcohol can be added to the polyhydric alcohol component. The addition amount is 30 mol% or less, preferably 10 mol% or less, based on the total alcohol, and is appropriately added within the range in which the resulting polyester has crystallinity.
Examples of polyhydric alcohol added as needed include 1,4-bis (hydroxymethyl) cyclohexane, polyethylene glycol, bisphenol A ethylene oxide adduct, bisphenol A propylene oxide adduct, glycerin and the like.

In the polyester resin (A), the molecular weight distribution is preferably sharp from the viewpoint of low-temperature fixability, and the molecular weight is preferably a relatively low molecular weight. As for the molecular weight of the polyester resin (A), the weight average molecular weight (Mw) is 5500-6500, the number average molecular weight (Mn) is 1300-1500 and The Mw / Mn ratio is preferably 2-5.
The molecular weight distribution of the polyester resin (A) is based on a molecular weight distribution diagram in which the horizontal axis is log (M: molecular weight) and the vertical axis is weight%. In the case of the polyester resin (A) used in the present invention, in this molecular weight distribution diagram, it is preferable to have a molecular weight peak in the range of 3.5 to 4.0 (wt%), and the half width of the peak is 1. 5 or less is preferable.
In the polyester resin (A), the glass transition temperature (Tg) and the softening temperature [T (F _1/2 )] are desirably low so long as the heat-resistant storage stability of the toner is not deteriorated. Tg is 80 to 130 ° C., preferably 80 to 125 ° C., and T (F _1/2 ) is 80 to 130 ° C., preferably 80 to 125 ° C. When Tg and T (F _1/2 ) are higher than the above ranges, the lower limit fixing temperature of the toner is increased, so that the low temperature fixing property of the toner is deteriorated.

Whether or not the resin fine particles in the present invention have crystallinity can be confirmed by whether or not a peak exists in the X-ray diffraction pattern by the powder X-ray diffractometer. The polyester resin (A) having crystallinity used in the present invention has a diffraction pattern in which at least one diffraction peak exists at a position where 2θ is 20 ° to 25 °, and preferably 2θ is at least (i It is characterized in that diffraction peaks are present at positions of 19 ° to 20 °, (ii) 21 ° to 22 °, (iii) 23 ° to 25 °, and (iv) 29 ° to 31 °.
The powder X-ray diffraction measurement was performed using a Rigaku Electric RINT1100, using a wide-angle goniometer under the conditions of a tube bulb with Cu and a tube voltage-current of 50 kV-30 mA.

As the colorant, known pigments and dyes capable of obtaining yellow, magenta, cyan, and black toners can be used.
For example, the yellow pigments include cadmium yellow, pigment yellow 155, benzimidazolone, mineral fast yellow, nickel titanium yellow, navel yellow, naphthol yellow S, Hansa yellow G, Hansa yellow 10G, benzidine yellow GR, quinoline yellow lake, Permanent yellow NCG, tartrazine lake and the like can be mentioned.

  Examples of the orange pigment include molybdenum orange, permanent orange GTR, pyrazolone orange, Vulcan orange, indanthrene brilliant orange RK, benzidine orange G, indanthrene brilliant orange GK and the like.

  Examples of red pigments include Bengala, Quinacridone Red, Cadmium Red, Permanent Red 4R, Resol Red, Pyrazolone Red, Watching Red Calcium Salt, Lake Red D, Brilliant Carmine 6B, Eosin Lake, Rhodamine Lake B, Alizarin Lake, Brilliant Carmine 3B, etc. Is mentioned.

  Examples of purple pigments include fast violet B and methyl violet lake.

  Examples of blue pigments include cobalt blue, alkali blue, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, phthalocyanine blue partially chlorinated, first sky blue, and indanthrene blue BC.

  Examples of the green pigment include chrome green, chromium oxide, pigment green B, and malachite green lake.

Examples of black pigments include azine dyes such as carbon black, oil furnace black, channel black, lamp black, acetylene black, and aniline black, metal salt azo dyes, metal oxides, and composite metal oxides.
These can use 1 type (s) or 2 or more types.

The toner for image formation according to the present invention may contain a charge control agent in the toner, if necessary.
For example, nigrosine, azine dyes containing an alkyl group having 2 to 16 carbon atoms (Japanese Patent Publication No. 42-1627), basic dyes such as C.I. I. Basic Yellow 2 (C.I. 41000), C.I. I. Basic Yellow 3, C.I. I. Basic Red 1 (C.I. 45160), C.I. I. Basic Red 9 (C.I. 42500), C.I. I. Basic Violet 1 (C.I. 42535), C.I. I. Basic Violet 3 (C.I. 42555), C.I. I. Basic Violet 10 (C.I. 45170), C.I. I. Basic Violet 14 (C.I. 42510), C.I. I. Basic Blue 1 (C.I. 42025), C.I. I. Basic Blue 3 (C.I. 51005), C.I. I. Basic Blue 5 (C.I. 42140), C.I. I. Basic Blue 7 (C.I. 42595), C.I. I. Basic Blue 9 (C.I. 52015), C.I. I. Basic Blue 24 (C.I. 52030), C.I. I. Basic Blue 25 (C.I. 52025), C.I. I. Basic Blue 26 (C.I. 44045), C.I. I. Basic Green 1 (C.I. 42040), C.I. I. Lake pigments of these basic dyes, such as Basic Green 4 (C.I. 42000), C.I. I. Solvent Black 8 (CI. 26150), quaternary ammonium salts such as benzoylmethyl hexadecyl ammonium chloride, decyl trimethyl chloride, or dialkyl tin compounds such as dibutyl or dioctyl, dialkyl tin borate compounds, guanidine derivatives, containing amino groups Polyamine resins such as vinyl polymers, condensation polymers containing amino groups, Japanese Patent Publication No. 41-20153, Japanese Patent Publication No. 43-27596, Japanese Patent Publication No. 44-6397, Japanese Patent Publication No. 45-26478 Metal complex salts of the monoazo dyes described, salicylic acid, dialkylsalicylic acid, naphthoic acid, dicarboxylic acid Zn, Al, Co, Cr described in Japanese Patent Publication No. 55-42752 and Japanese Patent Publication No. 59-7385 , Fe, etc. Metal complex, a copper phthalocyanine pigment obtained by sulfonation, organic boron salts, fluorine-containing quaternary ammonium salts, calixarene compounds, and the like. Naturally, color toners other than black should avoid the use of charge control agents that impair the desired color, and white metal salts of salicylic acid derivatives are preferably used.

  In the image forming toner of the present invention, the transferability and durability are further improved by externally adding inorganic fine particles such as silica, titanium oxide, alumina, silicon carbide, silicon nitride, boron nitride and resin fine particles to the base toner particles. I am letting.

  This effect can be obtained by covering the wax that lowers transferability and durability with these external additives and reducing the contact area due to the toner surface being covered with fine particles. The surface of these inorganic fine particles is preferably subjected to a hydrophobic treatment, and metal oxide fine particles such as silica and titanium oxide subjected to the hydrophobic treatment are preferably used. As the resin fine particles, polymethyl methacrylate or polystyrene fine particles having an average particle size of about 0.05 to 1 μm obtained by a soap-free emulsion polymerization method are suitably used. In addition, the combination of hydrophobized silica and hydrophobized titanium oxide increases the amount of hydrophobized titanium oxide externally added compared to the amount of hydrophobized silica externally charged. The toner can also be excellent in stability.

In combination with the above-mentioned inorganic fine particles, silica having a specific surface area of 20 to 50 m ² / g and resin fine particles having an average particle diameter of 1/100 to 1/8 of the average particle diameter of the toner are conventionally used. The durability can be improved by externally adding an external additive having a particle size larger than that of the additive to the toner. This is because the metal oxide particles externally added to the toner tend to be embedded in the base toner particles in the process where the toner is mixed and stirred with the carrier in the developing device, charged, and used for development. This is because it is possible to prevent the metal oxide fine particles from being embedded by externally adding an external additive having a particle size larger than that of the oxide fine particles to the toner.

  The above-mentioned inorganic fine particles and resin fine particles are contained (internally added) in the toner, but the effect is reduced as compared with the case of external addition, but the effect of improving transferability and durability can be obtained and the pulverization property of the toner can be improved. Can do. In addition, since external addition and internal addition can be used together to suppress embedding of externally added fine particles, excellent transferability can be stably obtained and durability can be improved.

  In addition, the following are mentioned as a typical example of the hydrophobization processing agent used here. Dimethyldichlorosilane, trimethylchlorosilane, methyltrichlorosilane, allyldimethyldichlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, p-chloroethyltrichlorosilane, Chloromethyldimethylchlorosilane, chloromethyltrichlorosilane, p-chlorophenyltrichlorosilane, 3-chloropropyltrichlorosilane, 3-chloropropyltrimethoxysilane, vinyltriethoxysilane, vinylmethoxysilane, vinyl-tris (β-methoxyethoxy) ) Silane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, divinyldichlorosilane, dimethylvinylchlorosilane, octyl Trichlorosilane, decyl-trichlorosilane, nonyl-trichlorosilane, (4-t-propylphenyl) -trichlorosilane, (4-t-butylphenyl) -trichlorosilane, dipentyl-dichlorosilane, dihexyl-dichlorosilane, dioctyl-dichlorosilane, dinonyl -Dichlorosilane, didecyl-dichlorosilane, didodecyl-dichlorosilane, dihexadecyl-dichlorosilane, (4-t-butylphenyl) -octyl-dichlorosilane, dioctyl-dichlorosilane, didecenyl-dichlorosilane, dinonenyl-dichlorosilane, di-2-ethylhexyl-dichlorosilane, di- 3,3-dimethylpentyl-dichlorosilane, trihexyl-chlorosilane, trioctyl-chlorosilane, tridecyl-chlorosilane Dioctyl-methyl-chlorosilane, octyl-dimethyl-chlorosilane, (4-t-propylphenyl) -diethyl-chlorosilane, octyltrimethoxysilane, hexamethyldisilazane, hexaethyldisilazane, diethyltetramethyldisilazane, hexaphenyldisilazane , Hexatolyl disilazane and the like. In addition, titanate coupling agents and aluminum coupling agents can also be used.

  In addition, as an external additive for the purpose of improving the cleaning property, a lubricant such as an aliphatic metal salt or a fine particle of polyvinylidene fluoride can be used in combination.

The image forming toner of the present invention can be used for both one-component development and two-component development.
When toner is used for a two-component developer, it is used by mixing with carrier powder. As the carrier in this case, a known carrier can be used, and examples thereof include iron powder, ferrite powder, magnetite powder, nickel powder, glass beads, and the like whose surface is coated with a resin, etc. The diameter is preferably a volume average particle diameter of 25 to 200 μm.

  As the toner container of the present invention, a one-component developer or a two-component developer containing the image forming toner of the present invention is filled, and a conventionally known shape can be used.

  The method for producing the toner of the present invention is not particularly limited, and includes a melt-kneading pulverization method and a polymerization method, a polyaddition reaction method using an isocyanate group-containing prepolymer, a solvent dissolution method, a solvent removal method, and a pulverization method. In addition, it can be produced by a melt spray method. Among these production methods, a melt kneading method, a polymerization method in which a monomer composition containing a specific crystalline polymer and a polymerizable monomer is directly polymerized in an aqueous phase (suspension polymerization method / emulsification method). Polymerization method), a polyaddition reaction method in which a composition containing a specific crystalline polymer and an isocyanate group-containing prepolymer is directly extended / crosslinked with amines in an aqueous phase, dissolved in a solvent, desolvated and pulverized. It is preferable to employ a method, and a conventionally known production method can be used.

  As an apparatus for melting and kneading toner, a batch type two roll, a Banbury mixer and a continuous type twin screw extruder, for example, KTK type twin screw extruder manufactured by Kobe Steel, TEM type twin screw extruder manufactured by Toshiba Machine Co., Ltd. , KCK's twin screw extruder, Ikegai Iron Works 'PCM type twin screw extruder, Kurimoto Iron Works' KEX type twin screw extruder, continuous single screw kneader, such as Bush's co-kneader Preferably used.

  In the polymerization method and the polyaddition reaction method using an isocyanate group-containing prepolymer, the emulsification (formation of droplets) treatment is mandatory by applying mechanical energy in the aqueous phase. Examples of the mechanical energy applying means include strong stirring such as homomixer, ultrasonic wave, and manton gorin, or ultrasonic vibration energy applying means.

  For pulverization, coarse pulverization can be performed using a hammer mill, a rotoplex, or the like, and a fine pulverizer using a jet stream or a mechanical pulverizer can be used. The average particle size is 3 to 15 μm. It is desirable to do so. Further, the pulverized product is adjusted in particle size to 5 to 20 μm by a wind classifier or the like.

  In the external addition of the external additive to the base toner, the base toner and the external additive are mixed and stirred using a mixer to coat the toner surface while the external additive is being crushed. At this time, it is important in terms of durability that external additives such as inorganic fine particles and resin fine particles are uniformly and firmly attached to the base toner.

An example of an image forming apparatus using the toner of the present invention as a developer will be described.
FIG. 2 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 mounted thereon. (ADF).
The copying apparatus main body (100) includes four image forming means (18) including various means for performing an electrophotographic process such as charging, developing, and cleaning around a photosensitive member (40) as a latent image carrier. Two parallel tandem image forming apparatuses (20) are 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. 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). Primary transfer means (62) for transferring the toner images of the respective colors formed on the photoconductor (40) to the intermediate transfer belt (10) at positions facing the photoconductor (40) via the intermediate transfer belt (10). ) Is arranged.

Further, below the intermediate transfer belt (10), a secondary transfer device (for transferring the toner images superimposed on the intermediate transfer belt (10) onto transfer paper conveyed from the paper feed table (200) in a batch. 22) is arranged. The secondary transfer device (22) is configured by spanning a secondary transfer belt (24), which is an endless belt, between two rollers (23), and a support roller (16) via an intermediate transfer belt (10). The toner image on the intermediate transfer belt (10) is transferred to the transfer paper. Next to the secondary transfer device (22), a fixing device (25) for fixing the image on the transfer paper is provided. The fixing device (25) is configured by pressing a pressure roller (27) against a fixing belt (26) which 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, as the secondary transfer device (22), a transfer roller or a non-contact charger may be arranged. In such a case, it is difficult to provide this sheet conveying function together.
In the illustrated example, the transfer paper is inverted under the secondary transfer device (22) and the fixing device (25) so as to record images on both sides of the transfer paper in parallel with the tandem image forming device (20). An inverting device (28) is provided.

The developer containing the toner is used for the developing device (4) of the image forming means (18).
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 image forming apparatus main body. 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, the document is set on the document table (30) of the automatic document feeder (400), or the document is opened on the contact glass (32) of the scanner (300) by opening the automatic document feeder (400). Then, the automatic document feeder (400) is closed and pressed by it.
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 other contact glass (32). When the document is set on the scanner, the scanner (300) is immediately driven to travel on the first traveling body (33) and the second traveling body (34). Then, the first traveling body (33) emits light from the light source, and the reflected light from the document surface is further reflected toward the second traveling body (34) and reflected by the mirror of the second traveling body (34). Then, the image is placed in the reading sensor (36) through the imaging lens (35), and the content of the original is read.

  When a start switch (not shown) is pressed, one of the support rollers (14), (15), and (16) is driven to rotate by the drive motor (not shown), and the other two support rollers are driven to rotate. The transfer belt (10) is rotated and conveyed. At the same time, the individual image forming means (18) rotates the photoreceptor (40) to form monochrome images of black, yellow, magenta, and cyan on each photoreceptor (40). Then, along with the conveyance of the intermediate transfer belt (10), these 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 one of paper feed cassettes (44) provided in multiple stages in the paper bank (43). The sheet is fed out from the sheet, separated one by one by a separation roller (45), put into a sheet feeding path (46), and conveyed by a conveying roller (47) to a sheet feeding path (48) in the copying machine main body (100). Guide and stop against the registration roller (49).
Alternatively, the sheet feeding roller (50) is rotated to feed out the sheets on the manual feed tray (51), separated one by one by the separation roller (52), and placed in the manual sheet feeding path (53). ) And stop.
Then, the registration roller (49) is rotated in synchronization with the composite color image on the intermediate transfer belt (10), and the sheet is fed between the intermediate transfer belt (10) and the secondary transfer device (22). The image is transferred by the next transfer device (22) and a color image is recorded on the sheet.

The sheet after the image transfer 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 claw. It is switched at (55), discharged by the discharge roller (56), and stacked on the 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 the paper discharge tray (56) is discharged by the discharge roller (56). 57) Drain up.
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, and the tandem image forming device (20). To prepare for image formation again.

<Measurement method>
(1) Measurement of endothermic peak of toner or Tg of resin by DSC The temperature of the maximum peak appearing on the endothermic side of the DSC curve is 10 ° C./min in temperature rise rate by DSC-60A of Shimadzu Corporation, and the temperature range is 20 to 200 ° C. , Measured under conditions with a sample amount of 5 mg (see FIGS. 3 and 4 as examples).
(2) Measurement of Resin Acid Value and Hydroxyl Value The method for measuring the acid value and hydroxyl value of the resin is according to the method specified in JIS K0070. However, when the sample did not dissolve, a solvent such as dioxane or THF, o-dichlorobenzene was used as the solvent.
(3) Measurement of resin softening point An elevated flow tester CFT-100 manufactured by Shimadzu Corporation was used. The flow curve of this flow tester becomes the data shown in FIGS. 1A and 1B, from which each temperature can be read. In FIG. 1A, Ts is the softening temperature, Tfb is the outflow start temperature, and the melting temperature in the _1/2 method in FIG. 1B is the F _1/2 temperature.
The measurement conditions are load: 10 kg / cm ² , heating rate: 3.0 ° C./min, die diameter: 0.50 mm, die length: 10.0 mm
(4) Wax melting point measurement TG-DSC system TAS-100 manufactured by Rigaku Corporation was used. First, about 10 mg of a sample is placed in an aluminum sample container, which is placed on a holder unit and set in an electric furnace. Heat from room temperature to 180 ° C. at a heating rate of 10 ° C./min. The melting point was calculated from the contact point between the tangent line of the endothermic curve near the melting point and the base line using the analysis system in the TAS-100 system.
(5) Evaluation of heat-resistant storage stability After storing the toner in a constant temperature bath at 50 ° C. for 24 hours, 2 g of the toner was screened for 2 minutes with a 42 μm mesh screen, and the residual ratio on the wire mesh was defined as heat-resistant storage stability. A toner having better heat-resistant storage stability has a lower residual ratio.
◎: Remaining amount is small and very good ○: Remaining amount is small and relatively excellent △: Remaining amount is relatively large ×: Remaining amount is very large (6) Low-temperature fixability Replace the fixing roller with a PFA tube coating roller The temperature of the fixing roller was changed by 5 ° C. by using a modified Ricoh Color Copier Pretail 650 machine from which the silicone oil coating device was removed, and the temperature at which the low temperature fixability was possible was measured. The fixing roller was evaluated under the condition that no oil was applied, and the Ricoh full color PPC paper type 6200 was used as the transfer paper.
By changing the fixing temperature of the fixing unit alone, a copy image was obtained in which the image density by the Macbeth densitometer was 1.2. The copy image at each temperature was rubbed 10 times with a clock meter equipped with a sand eraser, the image density before and after that was measured, and the fixing rate was determined by the following formula.
Fixing rate (%) = [(image density after 10 times of sand eraser) / (previous image density)] × 100
The temperature at which a fixing rate of 70% or more was achieved was defined as the minimum fixing temperature. The criteria for determining low temperature fixability are as follows.
The evaluation results were expressed as follows.
A: Fixing starts at a very low temperature and the lower limit fixing temperature is low, and the fixing property is very low. B: Excellent fixing property at a low temperature. B: Lower fixing temperature equivalent to that of a conventional toner. This is the minimum fixing temperature above, and is inferior in low-temperature fixability.

Synthesis example 1
<Crystalline polyester resin No. Synthesis of 1>
A 5-liter four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple was added to 25 mol of 1,4-butanediol, 23.75 mol of fumaric acid, 1.65 mol of trimellitic anhydride, hydroquinone After adding 5.3 g and reacting at 160 ° C. for 5 hours, the temperature was raised to 200 ° C. and reacted for 1 hour, and further reacted at 8.3 KPa for 1 hour to obtain crystalline polyester resin No. 1 1 was obtained.

Synthesis Examples 2-3
<Crystalline polyester resin No. Synthesis of 2-3>
A crystalline polyester resin No. 1 was prepared in the same manner as in Synthesis Example 1 except that the raw materials were changed to the following. 2-3 were obtained.
(No. 2)
1,4-butanediol: 22.5 mol Ethylene glycol: 5 mol Fumaric acid: 23.75 mol Trimellitic anhydride: 5 mol Hydroquinone: 5.8 g
(No. 3)
1,4-butanediol: 23.75 mol Ethylene glycol: 1.25 mol Fumaric acid: 22.75 mol Trimellitic anhydride: 1.65 mol Hydroquinone: 4.8 g

<Example of synthesis of non-crystalline polyester>
(No. 4)
390 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 120 g of isophthalic acid, 38 g of 1,2,5-benzenetricarboxylic acid and 1 g of dibutyltin oxide Place in a neck flask, attach a thermometer, stainless steel stir bar, flow-down condenser, and nitrogen inlet tube, react in a mantle heater under a nitrogen stream at 220 ° C until the desired softening point is reached, resin No. 4 was obtained.

Reference example 1
<Production of toner by kneading and grinding>
The following toner composition was sufficiently mixed with a blender and then melt-kneaded (kneading temperature: 140 ° C., extrusion speed: 10 kg / hour, rolling gap: 2 mm, standing time until pulverization: 48 hours) with a twin screw extruder. Thereafter, this was pulverized and classified to obtain a base toner having a volume average particle diameter of about 7.6 μm. To 100 parts of the base toner, 0.4 part of hydrophobic silica (surface-treated product with hexamethyldisilazane, average particle size of primary particles is 0.02 μm) as an external additive is mixed with a Henschel mixer. And a cyan toner was obtained.
-Amorphous polyester resin No. 4 100 parts Polypropylene wax (melting point: 151 ° C) 5 parts Charge control agent (metal salt of salicylic acid derivative) 2 parts Colorant (copper phthalocyanine blue pigment) 6 parts

Reference example 2
A toner was obtained in the same manner as in Reference Example 1 except that the following changes were made in Reference Example 1.
Kneading temperature: 140 ° C.
Extrusion speed: 8kg / hour,
Rolling gap: 1mm,
Standing time until crushing: 24 hours

Comparative Example 1
A toner was obtained in the same manner as in Reference Example 1 except that the following changes were made in Reference Example 1.
Kneading temperature: 140 ° C.
Extrusion speed: 12kg / hour,
Rolling gap: 3mm,
Standing time until crushing: 72 hours

Comparative Example 2
A toner was obtained in the same manner as in Reference Example 1 except that the following changes were made in Reference Example 1.
Kneading temperature: 140 ° C.
Extrusion speed: 5kg / hour
Rolling gap: 0.5mm
Standing time until crushing: 4 hours

Example 1
A toner was obtained in the same manner as in Reference Example 2 except that the following changes were made in Reference Example 2.
-Amorphous polyester resin No. 4 48 parts-Crystalline polyester resin No. 4 1 52 parts

Example 2
A toner was obtained in the same manner as in Reference Example 2 except that the following changes were made in Reference Example 2.
-Amorphous polyester resin No. 4 52 parts-Crystalline polyester resin No. 4 48 parts

Example 3
In Example 2, except for changing following, to obtain a toner in the same manner as in Example 2.
-Crystalline polyester resin No. 2 48 parts

Example 4
In Example 3, except for changing following, to obtain a toner in the same manner as in Example 3.
-Crystalline polyester resin No. 3 48 parts

Example 5
In Example 4, except for changing following, to obtain a toner in the same manner as in Example 4.
・ Polypropylene wax (melting point: 145 ℃) 5 parts

For reference, FIG. 3 shows a DSC chart of the unstored toner of Example 2 as a typical example (an example of an almost intermediate value of B−A of 5 to 13 ° C.). FIG. Example 2 shows a DSC chart of toner after it has been stored in a constant temperature bath at 40 ° C. for 72 hours. From both figures, the maximum endothermic peak temperature (A) by DSC measurement of this untreated toner is 55.13 ° C., and the maximum endothermic peak by DSC measurement of the toner after being stored in a constant temperature bath at 40 ° C. for 72 hours. It can be seen that the temperature (B) = 64.95 ° C., and therefore B−A = 64.95−55.13 = 9.82 ° C.≈10 ° C.
FIG. 5 is a diagram for explaining another toner example in which the value of B-A is almost the lower limit value, and the temperature (A) of the maximum endothermic peak by DSC measurement during non-storage processing is adjusted to 55.11 ° C. example 2 close to the regulation) the maximum endothermic peak temperature measured by DSC of 72 hours after storage the toner at 40 ℃ (B) = 60.62 ℃ ( hence B-a = 60.62-55.11 = 5 .51).

It is a figure which shows the flow curve of the elevated flow tester CFT-100 type made by Shimadzu Corporation. FIG. 2 is a diagram illustrating an example of an image forming apparatus using the toner of the present invention as a developer. It is a DSC measurement chart before the thermostat treatment of the toner example of the present invention. 6 is a DSC measurement chart after treatment for 72 hours in a 40 ° C. constant temperature bath of a toner example of the present invention. 6 is a DSC measurement chart after treatment for 72 hours in a 40 ° C. constant temperature bath of another toner example of the present invention.

Explanation of symbols

4 Developing Device 10 Intermediate Transfer Belt 14 Support Roller 15 Support Roller 16 Support Roller 17 Intermediate Transfer Belt Cleaning Device 18 Image Forming Unit 20 Tandem Image Forming Device 21 Laser Exposure Device 22 Secondary Transfer Device 23 Roller 24 Endless Secondary Transfer Belt 25 Fixing device 26 Fixing belt 27 Pressure roller 25 Fixing device 28 Sheet reversing device 30 Document table 32 Contact glass 33 First traveling member 34 Second traveling member 35 Imaging lens 36 Reading sensor 40 Photosensitive member 42 Feeding roller 43 Paper bank 44 Paper feed cassette 45 Separator roller 46 Paper feed path 47 Transport roller 48 Paper feed path 49 Registration roller 50 Paper feed roller 51 Manual feed tray 52 Separation roller 53 Manual feed path 54 Registration roller 55 Switching claw 56 Ejection roller 57 Ejection tray 62 Primary Transfer means 100 Body,
200 Paper feed table 300 Scanner 400 Automatic document feeder (ADF)

Claims (14)

  In a toner containing at least a binder resin, a colorant, and a release agent, the binder resin contains a crystalline polyester resin (A) and an amorphous polyester resin, and the polyester resin (A ) Has a portion derived from 1,4-butanediol and a portion derived from fumaric acid, and the non-crystalline polyester resin is polyoxypropylene (2.2) -2,2-bis (4-hydroxy). Phenyl) propane-derived site, obtained by melt-kneading and pulverizing a toner composition containing the binder resin, and a maximum endothermic peak in a temperature range of 40 to 75 ° C. of an endothermic curve obtained by DSC measurement The peak temperature of the toner is A, and the toner is stored in a constant temperature bath at 40 ° C. for 72 hours, and then the endothermic curve obtained by DSC measurement is in the temperature range of 40 to 75 ° C. In the case where the peak temperature of the maximum endothermic peak definitive by B, the image forming toner, which is a 5 ≦ B-A ≦ 13. The image forming toner according to claim 1, wherein the content of the polyester resin (A) in the binder resin is 1 to 50% by weight. The softening temperature [T (F _1/2 )] of the polyester resin (A) is in the range of 80 to 130 ° C, and the glass transition temperature (Tg) thereof is in the range of 80 to 130 ° C. Item 3. The image forming toner according to Item 1 or 2. The image forming toner according to any one of claims 1 to 3, wherein the crystalline polyester resin (A) has an acid value of 20 to 45 mgKOH / g. The toner for image formation according to any one of claims 1 to 4, wherein the crystalline polyester resin (A) has a hydroxyl value of 5 to 50 mgKOH / g. The image forming toner according to claim 1, wherein the mold release agent contains a wax (C), and the melting point of the wax (C) is 70 to 150 ° C. 6. The image forming toner according to any one of claims 1 to 6, wherein the wax (C) is at least one of carnauba wax, polyethylene wax, and synthetic ester wax. A toner composition containing at least a binder resin, a colorant, and a release agent is dry-mixed, melt-kneaded in a kneader, allowed to stand for 24 to 48 hours, pulverized, and classified as necessary. The method for producing an image forming toner according to any one of claims 1 to 7. A one-component developer comprising the image forming toner according to claim 1. A two-component developer comprising the image forming toner according to any one of claims 1 to 7 and a carrier powder. A toner container filled with the developer according to claim 9. The electrostatic latent image formed on the image carrier is developed with toner, the toner image formed on the image carrier is transferred to an image support, and the transferred toner image is a roller-shaped or belt-shaped fixing member. An image forming method comprising: using the developer according to claim 9 or 10, comprising the step of obtaining a fixed image by heat and pressure fixing. Developing means for developing the electrostatic latent image formed on the image carrier with toner, transfer means for transferring the toner image formed on the image carrier to the image support, and transferring the transferred toner image to a roller or belt 11. An image forming apparatus including a fixing unit that obtains a fixed image by heating and pressing and fixing with a fixing member having a shape, wherein the developer according to claim 9 or 10 is loaded. In a process cartridge that integrally supports a photosensitive member (image carrier) and at least a developing unit selected from a charging unit, a developing unit, and a cleaning unit, and is detachable from the image forming apparatus main body, the developing unit includes a developing unit. A process cartridge that holds the developer, and the developer is the developer according to claim 9.

Images