JP4749225B2 - toner - Google Patents

Description

  The present invention relates to a toner for visualizing an electrostatic charge image formed on the surface of an image carrier such as a photoreceptor in electrophotography or electrostatic recording, and an image forming apparatus and an image forming method using the toner. .

  Image forming methods such as electrophotography, electrostatic recording, and electrostatic printing include a development process in which toner contained in a developer is temporarily attached to an image carrier such as a photoreceptor on which an electrostatic charge image is formed. In the transfer step, toner is transferred from the photoconductor to a transfer medium such as transfer paper, and then fixed on the paper surface in the fixing step.

In the fixing process, in order to prevent toner from adhering to the surface of the fixing roller, conventionally, the roller surface is formed of a material having excellent releasability from the toner (silicone rubber, fluorine resin, etc.), and further on the surface. In order to prevent offset and fatigue of the roller surface, the roller surface is coated with a thin film of liquid having high releasability such as silicone oil and fluorine oil.
However, this method is extremely effective in preventing toner offset. However, since a device for supplying the liquid for preventing offset is necessary, the fixing device becomes complicated, which is disadvantageous for energy saving. The application causes delamination between the layers constituting the fixing roller, resulting in an adverse effect of promoting the shortening of the life of the fixing roller.

Therefore, an oil-less fixing device that does not use a silicone oil supply device has been recently proposed.
The toner used in this oilless fixing needs to have a certain degree of releasability from the surface of the fixing member, so that the degree of polymerization of the resin is increased to increase the viscoelasticity as the toner. Alternatively, instead of applying oil to the surface of the fixing roller, a release agent such as low molecular weight polypropylene is added to the toner particles, and an anti-offset liquid is supplied from the toner particles during heating to improve the peelability from the surface of the fixing member. It is done.
For example, Patent Document 1 discloses an oilless color toner in which a release agent-encapsulating resin particle obtained by mixing a release agent emulsion with an emulsified polyester dispersion and performing granulation operation is dyed with a dye. Thereby, it is possible to obtain a toner having excellent color reproducibility and excellent offset resistance, wrapping resistance, and fixability even in oilless fixing.

On the other hand, as a toner characteristic used in such a heat roller type fixing device, it is desired to use a toner having a lower fixing minimum temperature as much as possible while maintaining hot offset resistance.
In particular, many of the oilless fixing devices as described above are provided with a cleaning roller in contact with the fixing roller or the pressure roller in order to remove toner adhering to the surface of the fixing roller. When such a fixing device is used over a long period of time, the toner accumulated on the fixing cleaning roller is melted by heat and reversely transferred to the fixing roller or the pressure roller, so-called reverse hot offset occurs. is there.
Therefore, attempts have been made to lower the service temperature of the fixing roller and the fixing cleaning roller to prevent toner from melting from the cleaning roller.
As described above, when the heat roller type fixing device is used while the temperature of the fixing roller is lowered, further improvement of the low temperature fixing property of the toner is required.

However, if the toner is fixed at a low temperature in this way, there is a problem that it becomes difficult to ensure a fixing temperature range (hot offset resistance) and maintain heat-resistant storage stability.
As a method for satisfying these two demands, many methods have conventionally been proposed in which the molecular weight distribution of the toner binder is widened from a low molecular weight to a high molecular weight (for example, see Patent Document 2 or 3).
However, as described in Patent Document 2 or 3, when the low molecular weight of the toner binder is reduced or the ratio of the low molecular weight component is increased to fix the toner at a low temperature, the storage stability in the high temperature range is stabilized. In addition, the occurrence of fusion during running becomes prominent, and troubles such as image quality deterioration due to changes in the charge amount are likely to occur.

In addition, as a toner excellent in all of low-temperature fixability, hot offset resistance, and heat-resistant storage stability, a production process including a high molecular weight process in which an isocyanate group-containing polyester prepolymer is polyadded with an amine in an organic solvent and an aqueous medium What is obtained by the method is disclosed (for example, refer to Patent Documents 4 and 5).
However, when the toner is used by lowering the temperature of the fixing roller by the above manufacturing method, the fixing becomes insufficient, and further improvement in low-temperature fixing property is required.

JP 7-56390 A Japanese Patent Publication No. 60-20411 Japanese Patent Publication No.51-23354 JP 2002-287400 A JP 2002-351143 A

  Therefore, the present invention has been made in view of the above circumstances, and is a toner that has excellent low-temperature fixability, maintains heat-resistant storage stability, and has good developability over a long period of time and can form a high-quality image. And an image forming apparatus and an image forming method using the same.

The features of the present invention, which is a means for solving the above problems, are listed below.
1. The present invention relates to a toner containing at least a binder resin and a colorant, wherein the binder resin is a secondary modified polyester obtained by crosslinking a primary modified prepolymer (B) having a polyester as a precursor (A). it contains the precursor (a), bisphenol a propylene oxide 3 mole adduct, produced using terephthalic acid and adipic acid, the weight average molecular weight before Symbol precursor (a) is 10,000 to 31,200 The toner is characterized by the following.
2. The toner of the present invention is 1. In the invention described in item 3, the precursor (A) has a weight average molecular weight of 19200 to 31200.
3. The toner of the present invention, 1. Or 2. In the invention described in the prepolymer (B), the precursor (A) was modified process, at least, and wherein the a is introducing a site reactive with the active hydrogen group Turkey.
4). In addition, the toner of the present invention is 2. In the invention described in item 2, the secondary modified polyester is obtained by reacting the prepolymer (B) with a compound (C) containing an active hydrogen group.
5. The toner of the present invention is 1. Or 4. In any one of the inventions, the functional group contained in the prepolymer (B) is an isocyanate group.
6). The toner of the present invention is 5. In the invention described in item 3, the isocyanate group is isophorone diisocyanate.
7). The toner of the present invention is 1. Or 6. In any one of the inventions, the content of the polyvalent isocyanate compound in the prepolymer (B) is 0.95 to 1.36 wt%.
8). The toner of the present invention is 1. Or 7. In the invention of any one of, characterized in that it is granulated in an aqueous medium.

9. The toner of the present invention is 1. Or 8. In the invention according to any one of the above, an oil layer and active hydrogen obtained by dissolving or dispersing a toner composition containing a binder component composed of a prepolymer (B) having a site capable of reacting with an active hydrogen group in an organic solvent The compound (C) having a group is dispersed in an aqueous medium to obtain an emulsified dispersion, and the prepolymer (B) having a site capable of reacting with an active hydrogen group in the emulsion dispersion has an active hydrogen group. It is characterized by being manufactured through a step of elongation and / or crosslinking reaction with the compound (C) to form toner particles and removing the organic solvent in the emulsified dispersion.
10. The toner of the present invention is 1. Or 9. In the invention according to any one of the above, the precursor (A) has a Tg of 30 to 50 ° C.
11. The toner of the present invention is 1. Or 10. In the invention according to any one of the above, Tg is in the range of 40 to 55 ° C.

12 The toner of the present invention is 1. To 11. In the invention according to any one of the above, the average circularity is 0.90 to 0.97.
13. The toner of the present invention is 1. Or 12. In the invention according to any one of the above, the volume average particle diameter is 3.0 to 8.0 μm, and the ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) is 1.00. It is characterized by being in a range of ˜1.40.
14 The toner of the present invention is 1. Thru 13. In any one of the inventions, the shape factor SF-1 is in the range of 100 to 180, and the shape factor SF-2 is in the range of 100 to 180.

15. The toner of the present invention is 1. Or 14. In the invention according to any one of the above, the magnetic material is contained.
16. The toner of the present invention is 1. Or 14. In the invention described in any one of the above, it is used by being mixed with a magnetic carrier coated with a resin.

  According to the present invention, it is possible to provide a toner for developing an electrostatic charge image that has an unprecedented level of low-temperature fixability and maintains hot offset resistance. Thereby, in the fixing device of the image forming apparatus, it is possible to achieve a level of energy saving that is not conventional. In addition, an image forming apparatus and an image forming method using the toner as a developer can form a high-quality image with good developability over the long term.

Embodiments of the present invention will be described below.
The toner of the present invention is a toner comprising at least a binder resin and a colorant, and the binder resin is a primary modification obtained from a polyester precursor (A) having an average molecular weight of at least 10,000 to 90,000. It contains a resin obtained by crosslinking and / or elongation reaction of polyester (B).
The toner obtained by crosslinking the conventionally used polyester (A) has a glass transition temperature in the vicinity of 70 ° C., and when the temperature of the fixing roller is lowered, the toner does not melt sufficiently and fixing is insufficient. There was a problem of becoming.
The toner of the present invention uses a polyester having a higher molecular weight as the polyester (A) used as a polymerization precursor. As a result, the glass transition temperature in the vicinity of the fixing lower limit temperature of the toner can be lowered, and also has a Tg capable of maintaining heat-resistant storage stability even in the hot offset occurrence temperature region, and further improving the low-temperature fixing property of the toner. In addition, heat resistant storage stability can be maintained.

In addition, it is preferable to use what has a glass transition temperature in the range of 30-50 degreeC for polyester (A) as a precursor substance of superposition | polymerization, More preferably, it exists in the range of 30-40 degreeC. It is preferable to use one.
The measurement of the glass transition point (Tg) is specifically determined by the following procedure. Using Shimadzu TA-60WS and DSC-60 as measurement devices, the measurement was performed under the following measurement conditions.
[Measurement condition]
Sample container: Aluminum sample pan (with lid)
Sample amount: 5mg
Reference: Aluminum sample pan (alumina 10mg)
Atmosphere: Nitrogen (flow rate 50 ml / min)
[Temperature conditions]
Starting temperature: 20 ° C
Temperature increase rate: 10 ° C / min
End temperature: 150 ° C
Holding time: None Temperature drop: 10 ° C / min
End temperature: 20 ° C
Holding time: None Temperature increase rate: 10 ° C / min
End temperature: 150 ° C
The analysis of the measurement results obtained as described above was performed using data analysis software (TA-60, version 1.52) manufactured by Shimadzu Corporation. The analysis method specifies a range of ± 5 ° C around the point showing the maximum peak on the lowest temperature side of the DrDSC curve which is the DSC differential curve of the second temperature rise, and uses the peak analysis function of the analysis software to specify the peak temperature Ask for. Next, the maximum endothermic temperature of the DSC curve is determined using the peak analysis function of the analysis software in the range of the peak temperature + 5 ° C. and −5 ° C. in the DSC curve. The temperature shown here corresponds to the Tg of the toner.

The molecular weight is measured by GPC (gel permeation chromatography) as follows. Stabilize the column in a heat chamber at 40 ° C., flow THF at a flow rate of 1 ml / min through the column at this temperature, and prepare a THF sample solution of resin prepared at a sample concentration of 0.05 to 0.6% by weight. Is measured by injecting 50 to 200 μl. In measuring the molecular weight of the sample, the molecular weight distribution of the sample was calculated from the relationship between the logarithmic value of the prepared calibration curve and the count using several types of monodisperse polystyrene standard samples. As the standard polystyrene samples for preparing the calibration curve, for example, Pressur e C hemica l C o . Or molecular weight made by Toyo Soda Industry Co., Ltd. is 6 × 10 ² , 2.1 × 10 ³ , 4 × 10 ³ , 1.75 × 10 ⁴ , 5.1 × 10 ⁴ , 1.1 × 10 ⁵ , 3.9. It is suitable to use x10 ⁵ , 8.6 × 10 ⁵ , 2 × 10 ⁶ , 4.48 × 10 ⁶ , and use at least about 10 standard polystyrene samples. An RI (refractive index) detector is used as the detector.

In the case of a resin obtained by crosslinking or elongation reaction of a polymerization unit substance, as the thermal characteristics of the resin, the longer the distance between the crosslinking points, the higher the flexibility as the resin and the lower the Tg value. .
By using a polyester having an average molecular weight in the range of 10,000 to 90,000 for the precursor (A) as the polymerization unit substance, the distance between the crosslinking points of the resin can be reduced as compared with a resin obtained by crosslinking a conventionally used polyester. It can elongate and the physical properties as a resin can be softened.
For this reason, the glass transition point (Tg) in the vicinity of the fixing lower limit temperature of the toner can be lowered, and the low-temperature fixing property can be improved. Furthermore, since the viscoelasticity of the toner in the hot offset temperature region can be maintained at a constant level, a toner having both low-temperature fixability and hot offset resistance can be obtained.

The glass transition point of the toner is preferably in the range of 40 to 55 ° C.
If it is less than 40 ° C., toner blocking and filming on the photosensitive member are likely to occur in the developing device, and if it exceeds 55 ° C., the low-temperature fixability tends to deteriorate.
The toner of the present invention uses the above-mentioned polyester (A) as a precursor substance and contains a resin containing this as a crosslinking unit, so that it has a glass transition point within the above range, and has a low temperature fixability and heat resistant storage. And a toner having both high durability and high durability.
Note that the glass transition point of the toner can be measured in the same manner as the glass transition point of the polyester resin.

  Further, the toner of the present invention comprises a toner material solution obtained by dissolving or dispersing at least a polymer having a site capable of reacting with a compound having an active hydrogen group, a polyester, a colorant, and a release agent in an organic solvent. Obtained by crosslinking and / or elongation reaction in an aqueous medium. Hereinafter, the constituent material and the manufacturing method of the toner will be described.

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

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

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

Examples of the polyvalent carboxylic acid (PC) include divalent carboxylic acid (DIC) and trivalent or higher polyvalent carboxylic acid (TC). (DIC) alone and (DIC) with a small amount of (TC) Mixtures are preferred. Divalent carboxylic acids (DIC) include alkylene dicarboxylic acids (succinic acid, adipic acid, sebacic acid, etc.); alkenylene dicarboxylic acids (maleic acid, fumaric acid, etc.); aromatic dicarboxylic acids (phthalic acid, isophthalic acid, terephthalic acid) And naphthalenedicarboxylic acid). Of these, preferred are alkenylene dicarboxylic acids having 4 to 20 carbon atoms and aromatic dicarboxylic acids having 8 to 20 carbon atoms. Examples of the trivalent or higher polyvalent carboxylic acid (TC) include aromatic polycarboxylic acids having 9 to 20 carbon atoms (such as trimellitic acid and pyromellitic acid). In addition, as polyhydric carboxylic acid (PC), you may make it react with polyhydric alcohol (PO) using the above-mentioned acid anhydride or lower alkyl ester (Methyl ester, ethyl ester, isopropyl ester, etc.).
The ratio of the polyhydric alcohol (PO) to the polycarboxylic acid (PC) is usually 2/1 to 1/1, preferably as the equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] and the carboxyl group [COOH]. Is 1.5 / 1 to 1/1, more preferably 1.3 / 1 to 1.02 / 1.

In addition, it is preferable that the polyester prepolymer (B) of this invention is obtained by making the polyester (A) which has a weight average molecular weight in the range of 10000-90000 react with a polyvalent isocyanate compound (PIC).
As the polyhydric alcohol (PO) used in the production of this polyester, the above-mentioned ones can be used, but among these, the alkylene oxide addition of C2-C12 alkylene glycol and bisphenols is preferred. Particularly preferred are alkylene oxide adducts of bisphenols and combinations thereof with alkylene glycols having 2 to 12 carbon atoms.

When the above-mentioned alkylene oxide adduct of bisphenols is used for the polyester (A), by extending the alkylene chain bonded to the benzene ring and increasing the molecular weight of the polyester (A) as a polymerization unit, The glass transition temperature can be lowered.
By doing so, the distance between the crosslinking points can be extended while reducing the content of the benzene skeleton per unit weight in the polyester resin, and the glass transition point of the polyester resin is more effective in the fixing lower limit region. This is preferable because it can be lowered.

Examples of the polyvalent isocyanate compound (PIC) include aliphatic polyisocyanates (tetramethylene diisocyanate, hexamethylene diisocyanate, 2,6-diisocyanatomethylcaproate, etc.); alicyclic polyisocyanates (isophorone diisocyanate, cyclohexylmethane diisocyanate, etc.) ); Aromatic diisocyanates (tolylene diisocyanate, diphenylmethane diisocyanate, etc.); araliphatic diisocyanates (α, α, α ′, α′-tetramethylxylylene diisocyanate, etc.); isocyanates; Those blocked with caprolactam or the like; and combinations of two or more of these.
The ratio of the polyvalent isocyanate compound (PIC) is usually 5/1 to 1/1, preferably as an equivalent ratio [NCO] / [OH] of the isocyanate group [NCO] and the hydroxyl group [OH] of the polyester having a hydroxyl group. 4/1 to 1.2 / 1, more preferably 2.5 / 1 to 1.5 / 1. When [NCO] / [OH] exceeds 5, low-temperature fixability deteriorates. When the molar ratio of [NCO] is less than 1, when a urea-modified polyester is used, the urea content in the ester is lowered and hot offset resistance is deteriorated.

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

Next, as the amines (C) to be reacted with the polyester prepolymer (B), a divalent amine compound (C1), a trivalent or higher polyvalent amine compound (C2), an amino alcohol (C3), an amino mercaptan (C4) ), Amino acid (C5), and C1-C5 amino group blocked (C6).
Examples of the divalent amine compound (C1) include aromatic diamines (phenylenediamine, diethyltoluenediamine, 4,4′-diaminodiphenylmethane, etc.); alicyclic diamines (4,4′-diamino-3,3′-dimethyldicyclohexyl). Methane, diamine cyclohexane, isophorone diamine, etc.); and aliphatic diamines (ethylene diamine, tetramethylene diamine, hexamethylene diamine, etc.) and the like. Examples of the trivalent or higher polyvalent amine compound (C2) include diethylenetriamine and triethylenetetramine. Examples of amino alcohol (C3) include ethanolamine and hydroxyethylaniline. Examples of amino mercaptan (C4) include aminoethyl mercaptan and aminopropyl mercaptan. Examples of the amino acid (C5) include aminopropionic acid and aminocaproic acid. Examples of the C1-C5 amino group blocked (C6) include ketimine compounds and oxazolidine compounds obtained from the C1-C5 amines and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.). Among these amines (C), preferred are C1 and a mixture of C1 and a small amount of C2.

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

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

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

  The peak molecular weight of (ii) is 1000-10000 normally, Preferably it is 2000-8000, More preferably, it is 2000-5000. If it is less than 1000, heat-resistant storage stability will deteriorate, and if it exceeds 10,000, low-temperature fixability will deteriorate. The hydroxyl value of (ii) is preferably 5 or more, more preferably 10 to 120, and particularly preferably 20 to 80. If it is less than 5, it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. As for the acid value of (ii), 1-5 are preferable, More preferably, it is 2-4. Since a high acid value wax is used as the wax, the low acid value binder leads to electrification and high volume resistance, so that it is easy to match the toner used for the two-component developer.

In addition, it is preferable that the glass transition point of binder resin exists in the range of 40-55 degreeC.
In the present invention, the binder resin constituting the toner contains a resin obtained by crosslinking and / or extending the polyester prepolymer (B) obtained from the above-described polyester (A) with the amine (C). The glass transition point (Tg) can be within the above range.
If the temperature is lower than 40 ° C., the heat-resistant storage stability of the toner is deteriorated. Since the urea-modified polyester is likely to be present on the surface of the obtained toner base particles, the toner of the present invention tends to have good heat-resistant storage stability even when the glass transition point is low, as compared with known polyester-based toners. Show.

(Coloring agent)
As the colorant, all known dyes and pigments can be used. For example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, ocher , Yellow lead, titanium yellow, polyazo yellow, oil yellow, Hansa yellow (GR, A, RN, R), pigment yellow L, benzidine yellow (G, GR), permanent yellow (NCG), Vulcan fast yellow (5G, R), Tartrazine Lake, Quinoline Yellow Lake, Anthrazan Yellow BGL, Isoindolinone Yellow, Bengala, Red Dan, Lead Zhu, Cadmium Red, Cadmium Mercury Red, Antimon Zhu, Permanent Red 4R, Para Red, Phi Sayred, Parachlor Ortonito Aniline Red, Resol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmine B, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Resol Rubin GX, Permanent Red F5R , Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Toluidine Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thio Indigo Red B, Thioindigo Maroon, Oil Red, Quinacridone Red, Pyrazolone Red Polyazo Red, Chrome Vermillion, Benzidine Orange, Perinone Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkaline Blue Lake, Peacock Blue Lake, Victoria Blue Lake, Metal Free Phthalocyanine Blue, Phthalocyanine Blue, Fast Sky Blue, Indanthrene Blue (RS, BC), indigo, ultramarine blue, bitumen, anthraquinone blue, fast violet B, methyl violet lake, cobalt purple, manganese purple, dioxane violet, anthraquinone violet, chrome green, zinc green, chromium oxide, pyridian, emerald green, pigment Green B, Naphthol Green B, Green Gold, Acid Green Lake, Malachite Green Lake, Lid Russian nin green, anthraquinone green, titanium oxide, zinc white, litbon and mixtures thereof can be used. The content of the colorant is usually 1 to 15% by weight, preferably 3 to 10% by weight, based on the toner.

  The colorant can also be used as a master batch combined with a resin. As a binder resin to be kneaded with the production of the master batch or the master batch, a polymer of styrene such as polystyrene, poly-p-chlorostyrene, polyvinyl toluene or the like, or a copolymer of these and a vinyl compound, Polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, fat Aromatic or alicyclic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffins, paraffin waxes and the like can be mentioned, and these can be used alone or in combination.

(Charge control agent)
Known charge control agents can be used, such as nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (fluorine-modified 4 Secondary ammonium salts or compounds, tungsten simple substances or compounds, fluorine activators, salicylic acid metal salts, and metal salts of salicylic acid derivatives. Specifically, Bontron 03 of a nigrosine dye, Bontron P-51 of a quaternary ammonium salt, Bontron S-34 of a metal-containing azo dye, E-82 of an oxynaphthoic acid metal complex, E-84 of a salicylic acid metal complex , Phenolic condensate E-89 (above, Orient Chemical Industries, Ltd.), quaternary ammonium salt molybdenum complex TP-302, TP-415 (above, Hodogaya Chemical Co., Ltd.), quaternary ammonium salt copy Charge PSY VP2038, copy blue PR of triphenylmethane derivative, copy charge of quaternary ammonium salt NEG VP2036, copy charge NX VP434 (manufactured by Hoechst), LRA-901, LR-147 which is a boron complex (Nippon Carlit) Manufactured), copper phthalocyanine, perylene, quinacridone, azo series Fee, a sulfonic acid group, a carboxyl group, and polymer compounds having a functional group such as quaternary ammonium salts. Of these, substances that control the negative polarity of the toner are particularly preferably used.
The amount of the charge control agent used is determined by the type of binder resin, the presence or absence of additives used as necessary, and the toner production method including the dispersion method, and is not uniquely limited. The amount is preferably in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin. The range of 0.2 to 5 parts by weight is preferable. When the amount exceeds 10 parts by weight, the chargeability of the toner is too high, the effect of the charge control agent is reduced, the electrostatic attraction with the developing roller is increased, the flowability of the developer is lowered, and the image density is lowered. Invite.

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

(External additive)
As the external additive for assisting the fluidity, developability and chargeability of the colored particles obtained in the present invention, inorganic fine particles can be preferably used. The primary particle diameter of the inorganic fine particles is preferably 5 × ¹⁰ -3 ~2μm, it is particularly preferably 5 × ¹⁰ -3 ~0.5μm. Moreover, it is preferable that the specific surface area by BET method is 20-500 m < ² > / g. The use ratio of the inorganic fine particles is preferably 0.01 to 5 wt% of the toner, and particularly preferably 0.01 to 2.0 wt%.
Specific examples of the inorganic fine particles include, for example, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, quartz sand, clay, mica, wollastonite, diatomaceous earth. Examples include soil, chromium oxide, cerium oxide, pengala, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride.

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

  Such a fluidizing agent can be surface-treated to increase hydrophobicity and prevent deterioration of flow characteristics and charging characteristics even under high humidity. For example, silane coupling agents, silylating agents, silane coupling agents having an alkyl fluoride group, organic titanate coupling agents, aluminum coupling agents, silicone oils, modified silicone oils and the like are preferable surface treatment agents. . In particular, it is preferable to use hydrophobic silica and hydrophobic titanium oxide obtained by subjecting silica and titanium oxide to the above surface treatment.

Next, a toner manufacturing method will be described. Here, although a preferable manufacturing method is shown, it is not limited to this.
(Toner production method)
1) A toner material solution is prepared by dispersing a colorant, unmodified polyester, a polyester prepolymer having an isocyanate group, and a release agent in an organic solvent.
The organic solvent is preferably volatile with a boiling point of less than 100 ° C. from the viewpoint of easy removal after toner base particle formation. Specifically, toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, ethyl acetate, methyl ethyl ketone, Methyl isobutyl ketone and the like can be used alone or in combination of two or more. In particular, aromatic solvents such as toluene and xylene and halogenated hydrocarbons such as methylene chloride, 1,2-dichloroethane, chloroform, and carbon tetrachloride are preferable. The usage-amount of an organic solvent is 0-300 weight part normally with respect to 100 weight part of polyester prepolymers, Preferably it is 0-100 weight part, More preferably, it is 25-70 weight part.

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

Further, in order to improve the dispersion in the aqueous medium, a dispersant such as a surfactant and resin fine particles is appropriately added.
As surfactants, anionic surfactants such as alkylbenzene sulfonates, α-olefin sulfonates, phosphate esters, alkylamine salts, amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, amine salt types such as imidazoline, Quaternary ammonium salt type cationic surfactants such as alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkyldimethylbenzylammonium salts, pyridinium salts, alkylisoquinolinium salts, benzethonium chloride, fatty acid amide derivatives, polyhydric alcohols Nonionic surfactants such as derivatives, for example, amphoteric surfactants such as alanine, dodecyldi (aminoethyl) glycine, di (octylaminoethyl) glycine and N-alkyl-N, N-dimethylammonium betaine And the like.

Further, by using a surfactant having a fluoroalkyl group, the effect can be obtained in a very small amount. Preferred anionic surfactants having a fluoroalkyl group include fluoroalkyl carboxylic acids having 2 to 10 carbon atoms and metal salts thereof, disodium perfluorooctanesulfonyl glutamate, 3- [ω-fluoroalkyl (C6-C11 ) Oxy] -1-alkyl (C3-C4) sodium sulfonate, 3- [ω-fluoroalkanoyl (C6-C8) -N-ethylamino] -1-propanesulfonic acid sodium, fluoroalkyl (C11-C20) carvone Acids and metal salts, perfluoroalkylcarboxylic acids (C7 to C13) and metal salts thereof, perfluoroalkyl (C4 to C12) sulfonic acids and metal salts thereof, perfluorooctanesulfonic acid diethanolamide, N-propyl-N- ( 2-Hydroxyethyl) Perful Olooctanesulfonamide, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (C6-C10) -N-ethylsulfonylglycine salt, monoperfluoroalkyl (C6-C16) ethyl phosphate, etc. Can be mentioned.
Product names include Surflon S-111, S-112, S-113 (Asahi Glass Co., Ltd.), Florard FC-93, FC-95, FC-98, FC-129 (Sumitomo 3M Co., Ltd.), Unidyne DS-101. DS-102 (manufactured by Daikin Industries, Ltd.), Megafac F-110, F-120, F-113, F-191, F-812, F-833 (manufactured by Dainippon Ink, Inc.), Xtop EF-102, 103, 104, 105, 112, 123A, 123B, 306A, 501, 201, 204 (manufactured by Tochem Products), and Fgentent F-100, F150 (manufactured by Neos).

As the cationic surfactants, aliphatic primary to have a fluoroalkyl group, 2 primary or secondary amine acids, aliphatic quaternary ammonium, such as perfluoroalkyl (C6 ~ C10) sulfonamide propyl trimethyl ammonium salt Salt, benzalkonium salt, benzethonium chloride, pyridinium salt, imidazolinium salt, trade names include Surflon S-121 (manufactured by Asahi Glass), Florard FC-135 (manufactured by Sumitomo 3M), Unidyne DS-202 (Daikin Industries) Smoke), Megafac F-150, F-824 (Dainippon Ink Co., Ltd.), Xtop EF-132 (Tochem Products), Footage F-300 (Neos), and the like.

As the resin fine particles, any resin can be used as long as it can form an aqueous dispersion, and it may be a thermoplastic resin or a thermosetting resin. Examples thereof include vinyl resins, polyurethane resins, epoxy resins, polyester resins, polyamide resins, polyimide resins, silicon resins, phenol resins, melamine resins, urea resins, aniline resins, ionomer resins, and polycarbonate resins. As the resin, two or more of the above resins may be used in combination.
Of these, vinyl resins, polyurethane resins, epoxy resins, polyester resins, and combinations thereof are preferred because an aqueous dispersion of fine spherical resin particles is easily obtained. For example, vinyl resins are polymers obtained by homopolymerization or copolymerization of vinyl monomers, such as styrene- (meth) acrylic acid ester copolymers, styrene-butadiene copolymers, (meth) acrylic acid-acrylic acid esters. Examples thereof include resins such as a polymer, a styrene-acrylonitrile copolymer, a styrene-maleic anhydride copolymer, and a styrene- (meth) acrylic acid copolymer. The average particle size of the resin fine particles is 5 to 200 nm, preferably 20 to 300 nm. In addition, inorganic compound dispersants such as tricalcium phosphate, calcium carbonate, titanium oxide, colloidal silica, and hydroxyapatite can also be used.

  As a dispersant that can be used in combination with the above resin fine particles and inorganic compound dispersant, the dispersed droplets may be stabilized by a polymer protective colloid. For example, acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid or maleic anhydride and other (meth) acrylic monomers containing hydroxyl groups Bodies such as acrylic acid-β-hydroxyethyl, methacrylic acid-β-hydroxyethyl, acrylic acid-β-hydroxypropyl, methacrylic acid-β-hydroxypropyl, acrylic acid-γ-hydroxypropyl, methacrylic acid-γ-hydroxy Propyl, acrylic acid-3-chloro-2-hydroxypropyl, methacrylic acid-3-chloro-2-hydroxypropyl, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerol monoacrylate, glycerol monomethacrylate Luric acid esters, N-methylol acrylamide, N-methylol methacrylamide, etc., vinyl alcohol or ethers with vinyl alcohol, such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, or compounds containing vinyl alcohol and a carboxyl group Esters such as vinyl acetate, vinyl propionate, vinyl butyrate, acrylamide, methacrylamide, diacetone acrylamide or their methylol compounds, acid chlorides such as acrylic acid chloride, methacrylic acid chloride, vinyl pyridine, vinyl pyrrolidone, vinyl Nitrogen compounds such as imidazole and ethyleneimine, or homopolymers or copolymers such as those having a heterocyclic ring thereof, polyoxyethylene, poly Xoxypropylene, polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, polyoxy Polyoxyethylenes such as ethylene nonylphenyl ester, celluloses such as methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose can be used.

  The dispersion method is not particularly limited, and known equipment such as a low-speed shear method, a high-speed shear method, a friction method, a high-pressure jet method, and an ultrasonic wave can be applied. Among these, the high-speed shearing method is preferable in order to make the particle size of the dispersion 2 to 20 μm. When a high-speed shearing disperser is used, the rotational speed is not particularly limited, but is usually 1000 to 30000 rpm, preferably 5000 to 20000 rpm. The dispersion time is not particularly limited, but in the case of a batch method, it is usually 0.1 to 5 minutes. The temperature during dispersion is usually 0 to 150 ° C. (under pressure), preferably 40 to 98 ° C.

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

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

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

(Average circularity)
The toner of the present invention preferably has an average circularity of 0.90 to 0.97. Average circularity SR = (peripheral length of circle having the same area as the projected particle area / perimeter length of projected particle image) × 100%. The closer the toner is to a true sphere, the closer to 100%. Toner having a high degree of circularity is easily affected by the developing electric field, and is developed faithfully along the electric field of the electrostatic latent image.
Thereby, a high-definition image with an appropriate image density can be formed with good reproducibility. When the average circularity is less than 0.90, it is difficult to obtain a satisfactory transferability and a high-quality image free from dust.

  The average circularity of the toner can be measured by a flow type particle image analyzer FPIA-2000 (manufactured by Toa Medical Electronics Co., Ltd.). As a specific measurement method, 0.1 to 0.5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant to 100 to 150 ml of water from which impure solids have been removed in advance. About 0.1 to 0.5 g. The suspension in which the sample is dispersed is obtained by performing dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and measuring the shape and distribution of the toner with the above apparatus at a dispersion concentration of 3000 to 10,000 / μl. .

(Average particle diameter, Dv / Dn)
The volume average particle diameter (Dv) of the toner of the present invention is preferably 3 to 8 μm, and the ratio (Dv / Dn) to the number average particle diameter (Dn) is in the range of 1.00 to 1.25. More preferably, By defining Dv / Dn in this way, it is possible to obtain a toner with high resolution and high image quality. In order to obtain a higher quality image, it is necessary to set Dv to 3 to 7 μm, Dv / Dn to 1.00 to 1.20, and particles 3 μm or less to 1% to 10% by number. More preferably, it is preferable to set Dv to 3 to 6 μm and Dv / Dn to 1.00 to 1.15. Such a toner is excellent in all of heat-resistant storage stability, low-temperature fixability, and hot offset resistance, and particularly excellent in image gloss when used in a full-color copying machine. Even if the toner balance is extended over a long period, the toner particle size fluctuations in the developer are reduced, and good and stable developability can be obtained even with long-term stirring in the developing device.

The measuring device used for measuring the average particle size and particle size distribution of the toner is a measuring device for measuring the particle size distribution of the toner particles by the Coulter counter method, such as Coulter Counter TA-II and Coulter Multisizer II (both manufactured by Coulter Co.). Can be mentioned. The measurement method is described below.
First, a surfactant (preferably alkylbenzene Hong salt) is added 0.1~5ml as dispersing agent in the electrolytic solution 100 to 150 ml. Here, the electrolytic solution is a solution prepared by preparing a 1% NaCl aqueous solution using primary sodium chloride. For example, ISOTON-II (manufactured by Coulter) can be used. Here, 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the measurement device is used to measure the volume and number of toner particles or toner using a 100 μm aperture as the aperture. Volume distribution and number distribution are calculated. From the obtained distribution, the volume average particle diameter (Dv) and the number average particle diameter (Dn) of the toner can be obtained.
As channels, 2.00 to less than 2.52 μm; 2.52 to less than 3.17 μm; 3.17 to less than 4.00 μm; 4.00 to less than 5.04 μm; 5.04 to less than 6.35 μm; 6 Less than 35 to 8.00 μm; less than 8.00 to less than 10.08 μm; less than 10.08 to less than 12.70 μm; less than 12.70 to less than 16.00 μm; less than 16.00 to less than 20.20 μm; Uses 13 channels of less than 40 μm; 25.40 to less than 32.00 μm; 32.00 to less than 40.30 μm, and targets particles having a particle size of 2.00 μm to less than 40.30 μm.

(Shape factor SF-1)
The toner of the present invention is preferably a toner having a shape factor SF-1 in the range of 100 to 180 and SF-2 in the range of 100 to 180. SF-1 is more preferably 110 to 170, more preferably 120 to 160, and particularly preferably 130 to 150. SF-2 is more preferably 110 to 170, more preferably 120 to 160, and particularly preferably 130 to 150.
The shape factors SF-1 and SF-2 are expressed by the following formulas (1) and (2) as described above.
SF-1 = {(MXLNG) ² / AREA} × (100π / 4) (1)
SF-2 = {(PERI) ² / AREA} × ( 100 / 4π ) (2)
When the value of SF-1 is 100, the shape of the toner becomes a true sphere, and becomes larger as the value of SF-1 increases. Further, when the value of SF-2 is 100, the unevenness does not exist on the toner surface, and as the SF-2 value increases, the unevenness of the toner surface becomes more prominent.
The shape factor SF-1 is 100 images of toner particles magnified by a magnification of 500 using an electron microscope (for example, FE-SEM (S-800) manufactured by Hitachi, Ltd., and the same applies hereinafter). Randomly sampled and the image information is sent via an interface to an image analysis device [eg, Nexus NEW CUBE ver. 2.5 (manufactured by NEXUS), Luzex III (manufactured by Nicole) and the like, and so on. It is a value obtained by introducing into and analyzing and calculating from equation (1).
The shape factor SF-2 is obtained by randomly sampling 50 toner particle images magnified to a magnification of 3500 times using an electron microscope, introducing the image information into an image analysis apparatus via an interface, and performing analysis. It is a value obtained from 2).

  When the shape factors SF-1 and SF-2 are both close to 100 and the shape of the toner is close to a true sphere, the contact between the toner and the toner or the toner and the image carrier becomes a point contact. Accordingly, the fluidity is increased and the adhesion between the toner and the image carrier is also weakened, and the transfer rate is increased. The dot reproducibility is also improved. On the other hand, when the toner shape factors SF-1 and SF-2 are large to some extent, the margin for cleaning increases, and there is no problem such as defective cleaning. Therefore, it is preferable that the shape factors SF-1 and SF-2 are in the range of 100 to 180 as a range in which the image quality is not deteriorated from the balance between the two.

(Developer)
The toner of the present invention can be mixed with a magnetic carrier and used as a two-component developer. In this case, the carrier to toner content ratio in the developer is preferably 1 to 10 parts by weight of toner with respect to 100 parts by weight of carrier. As the magnetic carrier, conventionally known ones such as iron powder, ferrite powder, magnetite powder, magnetic resin carrier having a particle diameter of about 20 to 200 μm can be used. Examples of the coating material include amino resins such as urea-formaldehyde resin, melamine resin, benzoguanamine resin, urea resin, polyamide resin, and epoxy resin. Polyvinyl and polyvinylidene resins such as acrylic resins, polymethyl methacrylate resins, polyacrylonitrile resins, polyvinyl acetate resins, polyvinyl alcohol resins, polyvinyl butyral resins, polystyrene resins and styrene acrylic copolymer resins, Halogenated olefin resins such as vinyl, polyester resins such as polyethylene terephthalate resin and polybutylene terephthalate resin, polycarbonate resins, polyethylene resins, polyvinyl fluoride resins, polyvinylidene fluoride resins, polytrifluoroethylene resins, polyhexafluoro Propylene resin, copolymer of vinylidene fluoride and acrylic monomer, copolymer of vinylidene fluoride and vinyl fluoride, tetrafluoroethylene and vinylidene fluoride and non- Monomers including a fluoro terpolymers such, and silicone resins. Moreover, you may contain electrically conductive powder etc. in coating resin as needed. As the conductive powder, metal powder, carbon black, titanium oxide, tin oxide, zinc oxide or the like can be used. These conductive powders preferably have an average particle diameter of 1 μm or less. When the average particle diameter is larger than 1 μm, it becomes difficult to control electric resistance.

  The toner of the present invention can also be used as a one-component magnetic toner that does not use a carrier or a non-magnetic toner.

(Image forming device)
An example of an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic sectional view showing an example of an image forming apparatus to which the image forming method of the present invention is applied. The digital copying machine shown in FIG. 1 includes a drum-shaped photoreceptor 1 inside using a well-known electrophotographic system. A charging device 2, an exposure device 3, a developing device 4, a transfer device 5, a cleaning device 6, and a fixing device 10 that perform an electrophotographic copying process are arranged around the photosensitive member 1 along a rotation direction indicated by an arrow A. ing. The exposure device 3 forms an electrostatic latent image on the photoreceptor 1 on the basis of an image signal obtained by reading a document placed on the document placing table 7 on the upper surface of the copying machine by a reading device (not shown). The electrostatic latent image formed on the photosensitive member 1 is converted into a toner image by the developing device 4, and the toner image is electrostatically transferred by the transfer device 5 to the transfer paper fed from the paper supply device 9. The transfer paper on which the toner image is placed is conveyed and fixed to the fixing device 10 and then discharged outside the apparatus. On the other hand, the untransferred portion and the photosensitive member 1 with dirt are cleaned by the cleaning device 6, and the next image forming step is started.

  Next, the fixing device 10 will be described in detail. FIG. 2 is a schematic cross-sectional view showing an example of a heat roller type fixing device. As a basic structure, the fixing roller 121 having a heating device 124 (hereinafter referred to as a heater) such as a halogen lamp and foaming on the core metal 126 are illustrated. A pressure roller 125 having an elastic layer 127 such as silicone rubber and being pressed against the fixing roller 121 is provided. A release layer 128 made of a PFA tube or the like is provided on the elastic layer 127 of the pressure roller 125. In the fixing roller 121, an elastic layer 122 such as silicone rubber is provided on a core metal 130, and a resin surface layer 123 having good releasability such as fluororesin is formed for the purpose of preventing adhesion due to toner viscosity. . The thickness of the elastic layer 122 is usually preferably about 100 to 500 μm in consideration of image quality and heat transfer efficiency during fixing. The resin surface layer 123 is composed of a PFA tube or the like like the pressure roller 125, and its thickness is preferably about 10 to 50 μm in consideration of mechanical deterioration. A temperature detector 129 is provided on the outer peripheral surface of the fixing roller 121, and the heater 124 is controlled so as to keep the temperature substantially constant by detecting the surface temperature of the fixing roller 121.

In the fixing device having such a configuration, the fixing roller 121 and the pressure roller 125 are pressed against each other with a predetermined pressure to form a fixing nip portion N, and are driven by a driving unit (not shown) to receive arrows. By rotating in the R21 direction and the arrow R25 direction, the transfer material P is nipped and conveyed at the fixing nip portion N described above. At this time, the fixing roller 121 is controlled to a predetermined temperature by the heater 124, and when the toner image T on the transfer paper P passes between the two rollers, it is melted by heat while receiving pressure, and the roller pair exits. By being cooled, it is fixed on the transfer paper P as a permanent image.
The pressure roller 125 has an outer diameter of 30 mm, a wall thickness of 6 mm, a surface covered with a conductive PFA tube, and an on-axis rubber hardness of 42 HS (Asuka C). The fixing roller 121 is made of an aluminum core and has a thickness of 0.4 mm. In this configuration, in order to obtain the nip N, pressure is applied to both ends of the roller, and the contact pressure at that time is 8.3 N / cm ² .

In the heat roller type fixing device 10 as described above, the toner on the fixing roller 121 is transferred onto the pressure roller 125 due to the use over time, and the toner is transferred, so that the back surface of the recording paper P becomes dirty. Occurs.
The fixing device 10 of the present invention includes a fixing cleaning roller 131 so as to contact the surface of the pressure roller 125 in order to remove such residual toner on the pressure roller 125.
Thereby, a small amount of toner adhering to the pressure roller 125 is removed, and contamination on the back surface of the transfer paper can be prevented.

Note that the temperature of the surface of the fixing roller 121 is preferably controlled to be in a range of 140 to 180 ° C. by the temperature detecting unit 129.
As described above, when the fixing device 10 including the fixing cleaning roller 131 is used at a high temperature, the toner accumulated on the fixing cleaning roller 131 is melted by heat and is reversely transferred to the pressure roller 125, so-called reverse hot offset. Occurs.
Since the toner of the present invention has improved low-temperature fixability, even if the surface temperature of the fixing roller 121 is used within the above range, a good image can be stably provided without causing fixing failure. Can do.

EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not limited by this.

<Production Example 1>
[Synthesis of Polyester (A1)]
809 parts of bisphenol A propylene oxide 3 mol adduct, 196 parts of terephthalic acid, 44 parts of adipic acid, 5.8 parts of trimellitic anhydride and dibutyltin oxide in a reaction vessel equipped with a cooling pipe, a stirrer and a nitrogen introducing pipe Two parts were added and reacted at normal pressure at 230 ° C. for 8 hours, and further reacted for 5 hours while dehydrating at a reduced pressure of 10 to 15 mmHg to obtain OHV52, AV0.8 polyester (A1).
The weight average molecular weight Mw of (A1) was 10200, and the glass transition point Tg was 30.2 ° C.

[Synthesis of Polyester Prepolymer (B1)]
409 parts of polyester (A1) described in Production Example 1 and 495 parts of ethyl acetate are placed in a reaction vessel equipped with a cooling pipe, a stirrer, and a nitrogen introduction pipe, dissolved with stirring at room temperature, and 95.5 parts of isophorone diisocyanate. Was added and reacted at 80 ° C. for 18 hours to obtain an ethyl acetate solution (solid content concentration 50.5%) of the polyester prepolymer (B1).
The polyester prepolymer solution obtained had a viscosity of 920 mPa · s / 25 ° C. and an isocyanate content of 1.59%.

(Example of toner production)
In a beaker, 14.3 parts of prepolymer (B1), 55 parts of polyester resin (A1) , and 78.6 parts of ethyl acetate were stirred and dissolved. Separately, 10 parts of rice wax as a release agent, 4 parts of copper phthalocyanine blue pigment and 100 parts of ethyl acetate were placed in a bead mill and dispersed for 30 minutes. The two liquids were mixed and stirred for 5 minutes at a rotational speed of 12,000 rpm using a TK homomixer, and then dispersed in a bead mill for 10 minutes. This is designated as toner material oil dispersion (1).
In a beaker, 306 parts of ion-exchanged water, 265 parts of tricalcium phosphate 10% suspension, and 0.2 part of sodium dodecylbenzenesulfonate were added, and this aqueous dispersion was stirred with a TK homomixer at 12,000 rpm. Toner oil dispersion (1) and ketimine compound 2 . 7 parts were added and reacted with stirring for 30 minutes. The dispersion after the reaction (viscosity: 5,500 mPa · s) is subjected to removal of the organic solvent at a temperature of 50 ° C. or less within 1.0 hour under reduced pressure, followed by filtration, washing and drying, and then air classification. A toner base having a shape was obtained.
100 parts of the mother particles obtained, a charge control agent (Orient Chemical Industries, Ltd. Bontoro emissions E -84) 0.25 parts were charged into a Q type mixer (manufactured by Mitsui Mining Co., Ltd.), the peripheral speed of the turbine blade to 50 m / sec Set and mixed. In this case, the mixing operation was performed for 2 minutes, 5 cycles of 1 minute pause, and the total treatment time was 10 minutes. Further, 0.5 part of hydrophobic silica (H2000, manufactured by Clariant Japan) was added and mixed. In this case, the mixing operation was performed at a peripheral speed of 15 m / sec for 5 cycles of 30 seconds of mixing and 1 minute to obtain the final toner (I).

<Production Example 2>
[Synthesis of Polyester (A2)]
Other than using 730 parts of bisphenol A propylene oxide 3 mol adduct, 65 parts bisphenol A ethylene oxide 2 mol adduct, 234 parts terephthalic acid, 23 parts adipic acid, 6.1 parts trimellitic anhydride and 2 parts dibutyltin oxide Produced polyester (A2) having OHV43 and AV0.7 in the same manner as in Production Example 1.
The weight average molecular weight Mw of (A2) was 13300, and the glass transition point Tg was 35.0 ° C.

[Synthesis of polyester prepolymer (B2)]
A polyester is produced in the same manner as in [Synthesis of polyester prepolymer (B1)] in Production Example 1 except that 422 parts of polyester (A2), 495 parts of ethyl acetate and 83.4 parts of isophorone diisocyanate described in Production Example 2 are used. An ethyl acetate solution of prepolymer (B2) (solid content concentration 50.5%) was obtained.
The viscosity of the polyester prepolymer solution was 1,380 mPa · s / 25 ° C., and the isocyanate content was 1.36%.

  Thereafter, the final toner (II) was obtained by the same operation as that described in Production Example 1 (Production Example of Toner).

<Production Example 3>
[Synthesis of Polyester (A3)]
649 parts of bisphenol A propylene oxide 3 mol adduct, 70 parts of bisphenol A propylene oxide 2 mol adduct, 65 parts of bisphenol A ethylene oxide 2 mol adduct, 234 parts of terephthalic acid, 37 parts adipic acid, trimellitic anhydride 6.5 A polyester (A3) of OHV32 and AV1.4 was obtained in the same manner as in Production Example 1, except that 2 parts and 2 parts of dibutyltin oxide were used.
The weight average molecular weight Mw of (A3) was 19200, and the glass transition point Tg was 40.0 ° C.

[Synthesis of polyester prepolymer (B3)]
Polyester (A3) described in Production Example 3 was used in the same manner as in [Synthesis of Polyester Prepolymer (B1)] in Production Example 1 except that 438 parts of polyester (A3), 495 parts of ethyl acetate and 67.3 parts of isophorone diisocyanate were used. An ethyl acetate solution (solid content concentration 50.5%) of the prepolymer (B3) was obtained.
The obtained polyester prepolymer solution had a viscosity of 2,460 mPa · s / 25 ° C. and an isocyanate content of 1.05%.

  Thereafter, the final toner (III) was obtained by the same operation as that described in Production Example 1 (Toner Production Example).

<Production Example 4>
[Synthesis of Polyester (A4)]
572 parts bisphenol A propylene oxide 3 mol adduct, 140 parts bisphenol A propylene oxide 2 mol adduct, 66 parts bisphenol A ethylene oxide 2 mol adduct, 244 parts terephthalic acid, 38 parts adipic acid, trimellitic anhydride 3.4 OHV28, AV1.5 polyester (A4) was obtained in the same manner as in Production Example 1 except that 2 parts and 2 parts of dibutyltin oxide were used.
The weight average molecular weight Mw of (A4) was 31200, and the glass transition point Tg was 44.5 ° C.

[Synthesis of Polyester Prepolymer (B4)]
An ethyl acetate solution of polyester prepolymer (B4) (solids concentration 50) was prepared in the same manner as in Production Example 2, except that 443 parts of polyester (A4) described in Production Example 4 and 495 parts of ethyl acetate and 62 parts of isophorone diisocyanate were used. .5%).
The resulting polyester prepolymer solution had a viscosity of 3,830 mPa · s / 25 ° C. and an isocyanate content of 0.95%.

  Thereafter, the final toner (IV) was obtained by the same operation as shown in Production Example 1 (Toner Production Example).

<Comparative Production Example 1>
[Synthesis of Polyester (A5)]
Except for using 81 parts of bisphenol A propylene oxide 2 mol adduct, 681 parts of bisphenol A ethylene oxide 2 mol adduct, 275 parts of terephthalic acid, 7 parts adipic acid, 22 parts trimellitic anhydride and 2 parts dibutyltin oxide, OHV54, AV0.9 polyester (A5) was obtained in the same manner as in Production Example 1.
The weight average molecular weight Mw of (A5) was 9200, and the glass transition point Tg was 54.3 ° C.

[Synthesis of polyester prepolymer (B5)]
An ethyl acetate solution of polyester prepolymer (B5) (solid content concentration) in the same manner as in Production Example 2, except that 404 parts of polyester (A5), 495 parts of ethyl acetate and 101 parts of isophorone diisocyanate described in Comparative Production Example 1 were used. 50.5%) was obtained.
The obtained polyester prepolymer solution had a viscosity of 960 mPa · s / 25 ° C. and an isocyanate content of 1.70%.

  Thereafter, a final toner (V) was obtained by the same operation as that shown in Production Example 1 (Production Example of Toner).

<Comparative Production Example 2>
[Synthesis of Polyester (A6)]
Bisphenol A propylene oxide 3 mol adduct 415 parts, bisphenol A propylene oxide 2 mol adduct 214 parts, bisphenol A ethylene oxide 2 mol adduct 134 parts, terephthalic acid 260 parts, adipic acid 20 parts, trimellitic anhydride 3.6 OHV20, AV1.8 polyester (A6) was obtained in the same manner as in Production Example 1, except that 2 parts and 2 parts of dibutyltin oxide were used.
The weight average molecular weight Mw of (A6) was 96000, and the glass transition point Tg was 59.6 ° C.

[Synthesis of polyester prepolymer (B6)]
An ethyl acetate solution of polyester prepolymer (B6) (solid content concentration) in the same manner as in Production Example 2, except that 457 parts of polyester (A6), 495 parts of ethyl acetate and 48 parts of isophorone diisocyanate described in Comparative Production Example 2 were used. 50.5%) was obtained.
The resulting polyester prepolymer solution had a viscosity of 6300 mPa · s / 25 ° C. and an isocyanate content of 0.68%.

  Thereafter, the final toner (VI) was obtained by the same operation as shown in Production Example 1 (Toner Production Example).

  The polyester resins (A1) to (A4) used in the toners (I) to (VI) according to the present invention described above and the polyester resins used in the toners (V) to (VI) manufactured for comparison ( Table 1 shows the physical properties relating to A5) to (A6).

  Using the toners (I) to (IV), the low temperature fixability and the high temperature offset resistance were evaluated. For comparison, the same evaluation was performed using the toners (V) to (VI). The evaluation items and evaluation methods for the toner are as follows.

<Fixability evaluation method>
A fixing device (surface pressure: 8.3 N / cm ² ) having the configuration shown in FIG. 2 is mounted on an imagio Neo 452 (manufactured by Ricoh Co., Ltd.), and a fixed image is obtained by changing the heater temperature. A mending tape (manufactured by 3M) is applied to the fixed image, and after applying a certain pressure, it is slowly peeled off. The image density before and after that is measured with a Macbeth densitometer, and the fixing rate is calculated by the following equation. The temperature of the fixing roller is lowered step by step, and the temperature at which the fixing rate represented by the following formula becomes 80% or less is defined as the fixing temperature.
Fixing rate (%) = tape adhesion image density / image density × 100

<Evaluation method of hot offset occurrence temperature>
Using a fixing device similar to the above-described fixing property evaluation method, a solid black image of 2 cm × 2 cm was prepared, and when a fixed image was obtained by changing the heater temperature to obtain a fixed image, the temperature at which hot offset occurred To do.

  Table 2 shows the evaluation results of the toner.

As can be seen from Table 2, in Examples 1 to 4 using the toners (I) to (IV) according to the present invention, good results were obtained that were excellent in low-temperature fixability and maintained hot offset resistance. Obtained.
On the other hand, the toners (V) and (VI) used in Comparative Examples 1 and 2 have the molecular weight of the polyester as the precursor material outside the specified range of the present invention, and are inferior in low-temperature fixability. became.

1 is a schematic cross-sectional view illustrating an example of an image forming apparatus to which an image forming method of the present invention is applied. FIG. 3 is a schematic cross-sectional view illustrating an example of a heat roller type fixing device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charging device 3 Exposure device 4 Developing device 5 Transfer device 6 Cleaning device 7 Document placing table 8 Registration roller
9 Feeder 10 Fixing Device 121 Fixing Roller 122 Elastic Layer 123 Resin Surface Layer 124 Heating Device (Heater)
125 Pressure roller 126 Core metal 127 Elastic layer 128 Release layer 129 Temperature detecting means 130 Core metal 131 Fixing cleaning roller 40 Image forming unit

Claims (16)

At least in a toner containing a binder resin and a colorant,
The binder resin contains a secondary modified polyester obtained by crosslinking the primary modified prepolymer (B) having a polyester as a precursor (A) ,
The precursor (A) is produced using bisphenol A propylene oxide 3 mol adduct, terephthalic acid and adipic acid,
The weight average molecular weight before Symbol precursor (A), the toner, which is a 10,000 to 31,200. The toner according to claim 1.
The toner according to claim 1, wherein the precursor (A) has a weight average molecular weight of 19200 to 31200 . The toner according to claim 1 or 2 ,
The toner according to claim 1, wherein the prepolymer (B) is obtained by modifying the precursor (A) and introducing at least a site capable of reacting with an active hydrogen group. The toner according to claim 3 .
The toner, wherein the secondary modified polyester is obtained by reacting the prepolymer (B) with a compound (C) containing an active hydrogen group . In the toner according to any one of claims 1 to 4 ,
The toner according to claim 1, wherein the functional group contained in the prepolymer (B) is an isocyanate group . The toner according to claim 5 .
A toner wherein the isocyanate group is isophorone diisocyanate . The toner according to any one of claims 1 to 6,
The toner according to claim 1, wherein the content of the polyvalent isocyanate compound in the prepolymer (B) is 0.95 to 1.36 wt% . The toner according to any one of claims 1 to 7,
The toner is granulated in an aqueous medium . The toner according to any one of claims 1 to 8,
The toner includes an oil layer obtained by dissolving or dispersing a toner composition containing a binder component composed of a prepolymer (B) having a site capable of reacting with an active hydrogen group in an organic solvent, and a compound having an active hydrogen group ( C) is dispersed in an aqueous medium to obtain an emulsified dispersion, in which the prepolymer (B) having a site capable of reacting with an active hydrogen group is converted to a compound (C) having an active hydrogen group A toner produced by a process of extending and / or crosslinking to form toner particles and removing an organic solvent in an emulsified dispersion . The toner according to claim 1,
The precursor (A) has a Tg of 30 to 50 ° C. The toner according to any one of claims 1 to 10,
The toner has a Tg in the range of 40 to 55 ° C. The toner according to any one of claims 1 to 11,
The toner has an average circularity of 0.90 to 0.97 . The toner according to any one of claims 1 to 12 ,
The toner has a volume average particle diameter of 3.0 to 8.0 μm and a ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) of 1.00 to 1.40. Toner characterized by being in range . The toner according to any one of claims 1 to 13,
The toner has a shape factor SF-1 in the range of 100 to 180 and a shape factor SF-2 in the range of 100 to 180.
Toner characterized by the above. The toner according to any one of claims 1 to 14,
The toner contains a magnetic material.
Toner characterized by the above. The toner according to any one of claims 1 to 14,
The toner is used by mixing with a magnetic carrier coated with a resin.
Toner characterized by the above.

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