JPH11133666A - Dry toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dry toner which is excellent in powder fluidity and transferability and also, excellent in any of heat-resistingly preservable properties, low-temp. fixation properties and to offset resistance by specifying the Wadell's practical sphericity of particles of the toner and using as the toner binder, a binder resin consisting of a polyester modified with urea bonds. SOLUTION: In this dry toner consisting of a toner binder and a colorant, the Wadell's practical sphericity of the toner particles is 0.90 to 1.00 and the toner binder consists of a polyester modified with urea bonds. Further, the Wadell's practical sphericity of the toner particles is preferably 0.95 to 1.00 and more desirably 0.98 to 1.00, wherein the Wadell's practical sphericity of each of all the toner particles is not required to fall within any of these ranges and such toner particles having average Wadell's practical sphericity within any of these ranges can satisfactorily be used. Also, the media value of particle diameters of the toner particles is ordinarily 2 to 20 μm and preferably 3 to 10 μm. As the polyester modified with urea bonds, e.g. a reactant of a polyester prepolymer having isocyanate groups with a compound selected from amines is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a dry toner used for electrophotography, electrostatic recording, electrostatic printing, and the like.

[0002]

2. Description of the Related Art Conventionally, styrene resins, dry toners used for electrophotography, electrostatic recording, electrostatic printing, and the like have been used.
A toner binder such as polyester is melt-kneaded with a coloring agent or the like, and finely pulverized. These dry toners are developed and transferred to paper or the like, and then fixed by heating and melting using a hot roll. At that time, if the temperature of the hot roll is too high, there is a problem (hot offset) that the toner is excessively melted and fused to the hot roll. On the other hand, if the temperature of the hot roll is too low, the toner does not melt sufficiently and the fixing becomes insufficient. From the viewpoint of energy saving and downsizing of apparatuses such as copying machines, toners having a higher hot offset generation temperature (hot offset resistance) and a lower fixing temperature (low temperature fixing property) are required. Further, it is necessary to have a heat-resistant storage property in which the toner does not block during storage and at ambient temperature in the apparatus. Particularly in full-color copying machines and full-color printers, since the gloss and color mixing of the image are required, the toner must have a lower melt viscosity, and a sharp-melt polyester toner binder is used. ing. Since hot offset is likely to occur in such a toner, silicone oil or the like is conventionally applied to a heat roll in a full-color device. However, the method of applying silicone oil to the heat roll requires an oil tank and an oil application device, and the device becomes complicated and large. It also causes deterioration of the heat roll and requires maintenance at regular intervals. Furthermore, copy paper, O
It is inevitable that oil adheres to films for HP (overhead projector), especially OHP
In this case, there is a problem that the color tone is deteriorated by the attached oil.
On the other hand, in recent years, there has been an increasing need for a toner having a smaller particle size for higher image quality and higher resolution. However, the conventional kneaded and ground toner has an irregular shape, so that when the particle size is small, the powder fluidity becomes insufficient, making it difficult to supply the toner to the developing device and improving the transferability. There is a problem that gets worse.

[0003] Among the above-mentioned problems, those which are compatible with heat resistance storage stability, low-temperature fixability and hot offset resistance are as follows.
Polyester partially crosslinked with a polyfunctional monomer as a toner binder
No. 109825), those using a urethane-modified polyester as a toner binder (Japanese Patent Publication No. 7-1)
01318) and the like. Further, as a method for reducing the amount of oil applied to a hot roll for full color use, a method in which polyester fine particles and wax fine particles are granulated (Japanese Patent Laid-Open No. 7-56390) has been proposed.

Further, the powder fluidity when the particle size is reduced,
To improve the transferability, a polymerizable toner prepared by dispersing a vinyl monomer composition containing a colorant, a polar resin and a releasing agent in water and then subjecting the dispersion to suspension polymerization (Japanese Patent Application Laid-Open No. 9-43909).
Japanese Patent Application Laid-Open No. 9-341), a toner obtained by spheroidizing a toner composed of a polyester resin in water using a solvent.
No. 67) has been proposed.

[0005]

However, all of the toners disclosed in (1) to (4) have insufficient powder flowability and transferability, and cannot achieve high image quality by reducing the particle size. Furthermore, the toners disclosed in and are still insufficient in compatibility between heat-resistant storage stability and low-temperature fixability, and cannot be used for full color because they do not exhibit glossiness. In addition, the toner disclosed in JP-A-2003-115122 has insufficient low-temperature fixing property and does not have satisfactory hot offset property in oil-less fixing.
Although the toners disclosed in (1) and (2) have an effect of improving powder fluidity and transferability, the toners disclosed in (2) have insufficient low-temperature fixability and require much energy for fixing. There is. In particular, this problem is remarkable in full-color toner. Although the toner disclosed in JP-A No. 5-25967 is more excellent in low-temperature fixability, it has insufficient hot offset resistance, and does not make it unnecessary to apply oil to a hot roll in full-color applications.

[0006]

Means for Solving the Problems The present inventors have found that, when a toner having a small particle size is used, the powder fluidity and transferability are excellent, and at the same time, the heat storage stability, low-temperature fixability and hot offset resistance are all satisfactory. The present invention has been achieved as a result of intensive studies to develop an excellent dry toner, particularly a dry toner which is excellent in glossiness of an image when used in a full-color copying machine or the like and does not require oil application to a hot roll. That is, the present invention relates to a dry toner comprising a toner binder and a colorant, wherein the toner has a Wadell practical sphericity of 0.90 to 1.00, and the toner binder is a polyester (i) modified with a urea bond. The dry toner is characterized by comprising:

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. In the present invention, Wadell's practical sphericity is a value represented by (diameter of a circle equal to the projected area of a particle) ÷ (diameter of a minimum circle circumscribing a projected image of the particle). It can be measured by observation. Wadell's practical sphericity is usually 0.90 to 1.00, preferably 0.9 to 1.00.
5 to 1.00, more preferably 0.98 to 1.00. In the present invention, the practical sphericity of all the toner particles need not be in the above range, but may be in the above range as an average value. The particle diameter of the toner is a medium diameter (d
50) is usually 2 to 20 μm, preferably 3 to 10 μm.

Examples of the polyester (i) modified by a urea bond include a reaction product of a polyester prepolymer (A) having an isocyanate group and an amine (B). Examples of the polyester prepolymer (A) having an isocyanate group include a polycondensate of a polyol (1) and a polycarboxylic acid (2), which is obtained by further reacting a polyester having an active hydrogen group with a polyisocyanate (3). No. Examples of the active hydrogen group of the polyester include a hydroxyl group (alcoholic hydroxyl group and phenolic hydroxyl group), an amino group, a carboxyl group,
Mercapto groups and the like are preferable, and among these, an alcoholic hydroxyl group is preferable.

As the polyol (1), diol (1)
-1) and tri- or higher valent polyol (1-2). (1-1) alone or (1-1) and a small amount of (1-)
Mixtures of 2) are preferred. As the diol (1-1), alkylene glycol (ethylene glycol, 1,
2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, etc .; alkylene ether glycols (diethylene glycol, triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetra) Alicyclic diols (1,4-cyclohexanedimethanol, hydrogenated bisphenol A, etc.); bisphenols (bisphenol A, bisphenol F, bisphenol S, etc.); alkylene oxides of the above alicyclic diols (ethylene Oxides, propylene oxide, butylene oxide, etc.) adducts; alkylene oxides of the above bisphenols (ethylene oxide, propylene oxide, butyl oxide) Adducts and the like. Of these, preferred are those having 2 carbon atoms.
~ 12 alkylene glycol and alkylene oxide adducts of bisphenols, particularly preferred are alkylene oxide adducts of bisphenols,
And a combination thereof with an alkylene glycol having 2 to 12 carbon atoms. Examples of the trivalent or higher polyol (1-2) include polyhydric aliphatic alcohols of 3 to 8 or higher (glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, etc.); trihydric or higher phenols (Trisphenol P
A, phenol novolak, cresol novolak, etc.); and alkylene oxide adducts of the above trivalent or higher polyphenols.

As the polycarboxylic acid (2), dicarboxylic acid (2-1) and tricarboxylic or higher polycarboxylic acid (2-
2), and (2-1) alone or a mixture of (2-1) and a small amount of (2-2) is preferable. Examples of the dicarboxylic acid (2-1) include alkylenedicarboxylic acids (such as succinic acid, adipic acid, and sebacic acid); alkenylene dicarboxylic acids (such as maleic acid and fumaric acid); and aromatic dicarboxylic acids (phthalic acid, isophthalic acid, and terephthalic acid). , Naphthalenedicarboxylic acid, etc.). 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 polycarboxylic acid (2-2) include aromatic polycarboxylic acids having 9 to 20 carbon atoms (such as trimellitic acid and pyromellitic acid). The polycarboxylic acid (2) may be reacted with the polyol (1) using the above-mentioned acid anhydride or lower alkyl ester (eg, methyl ester, ethyl ester, isopropyl ester).

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

Examples of the polyisocyanate (3) include aliphatic polyisocyanates (such as tetramethylene diisocyanate, hexamethylene diisocyanate, and 2,6-diisocyanatomethylcaproate); alicyclic polyisocyanates (such as isophorone diisocyanate and cyclohexylmethane diisocyanate). Aromatic diisocyanates (such as tolylene diisocyanate and diphenylmethane diisocyanate); araliphatic diisocyanates (such as α, α, α ′, α′-tetramethylxylylene diisocyanate); isocyanurates; , Caprolactam and the like; and combinations of two or more of these.

The ratio of the polyisocyanate (3) is usually 5/1 to 1/1, as the equivalent ratio [NCO] / [OH] of the isocyanate group [NCO] and the hydroxyl group [OH] of the polyester having a hydroxyl group. Is 4/1 to 1.2 / 1, more preferably 2.5 / 1 to 1.5 / 1. [NCO]
If / [OH] exceeds 5, the low-temperature fixability deteriorates. [NC
When the molar ratio of O] is less than 1, the urea content in the modified polyester becomes low, and the hot offset resistance deteriorates.
The content of the polyisocyanate (3) constituent component in the prepolymer (A) having a terminal isocyanate group is usually 0.5 to 40% by weight, preferably 1 to 30% by weight, and more preferably 2 to 20% by weight. It is. If the content is less than 0.5% by weight, the hot offset resistance is deteriorated and the heat storage stability and the low-temperature fixability are both disadvantageous. Also, 4
If it exceeds 0% by weight, the low-temperature fixability deteriorates.

The number of isocyanate groups per molecule in the prepolymer (A) having isocyanate groups is usually at least 1, preferably 1.5 to 3 on average, and more preferably 1.8 to 2 on average. .5. If the number is less than one per molecule, the molecular weight of the urea-modified polyester becomes low, and the hot offset resistance deteriorates.

As the amines (B), diamines (B
1) Triamine or higher polyamine (B2), amino alcohol (B3), aminomercaptan (B4), amino acid (B5), and those obtained by blocking amino groups B1 to B5 (B6). Examples of the diamine (B1) include aromatic diamines (phenylenediamine, diethyltoluenediamine, 4,4′-diaminodiphenylmethane, etc.); alicyclic diamines (4,4′-diamino-3,
3 ′ dimethyldicyclohexylmethane, diaminecyclohexane, isophoronediamine, etc.); and aliphatic diamines (ethylenediamine, tetramethylenediamine,
Hexamethylenediamine, etc.). Examples of the trivalent or higher polyamine (B2) include diethylenetriamine and triethylenetetramine. Examples of the amino alcohol (B3) include ethanolamine and hydroxyethylaniline. Examples of the aminomercaptan (B4) include aminoethylmercaptan and aminopropylmercaptan. Examples of the amino acid (B5) include aminopropionic acid and aminocaproic acid. Examples of the product (B6) in which the amino group of B1 to B5 is blocked include the amines and ketones of B1 to B5 (acetone, methyl ethyl ketone,
Ketimine compounds and oxazoline compounds obtained from methyl isobutyl ketone. Among these amines (B), preferred are B1 and a mixture of B1 and a small amount of B2.

Further, if necessary, the molecular weight of the urea-modified polyester can be adjusted by using an elongation terminator. Examples of the elongation terminator include monoamines (diethylamine, dibutylamine, butylamine, laurylamine, etc.), and those obtained by blocking them (ketimine compounds).

The ratio of the amines (B) depends on the isocyanate groups in the prepolymer (A) having isocyanate groups.
The equivalent ratio [NCO] / [NHx] of [NCO] and the amino group [NHx] in the amines (B) is usually 1/2 to 2/1,
It is preferably from 1.5 / 1 to 1 / 1.5, more preferably from 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 (i) becomes low, and the hot offset resistance deteriorates. In the present invention, the polyester (i) modified with a urea bond 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 from 100/0 to 10/90, preferably from 80/20 to 20/80, and more preferably from 60/40 to 30/70. When the molar ratio of the urea bond is less than 10%, the hot offset resistance deteriorates.

The urea-modified polyester of the present invention (i)
Is manufactured by a one-shot method or a prepolymer method. The weight average molecular weight of the urea-modified polyester (i) is usually 10,000 or more, preferably 20,000 to 10,000,000, and more preferably 30,000 to 1,000,000. If it is less than 10,000, the hot offset resistance deteriorates. The number average molecular weight of the urea-modified polyester is not particularly limited when unmodified polyester (ii) described below is used,
The number average molecular weight which is easy to obtain to obtain the weight average molecular weight may be used. (I) When used alone, the number average molecular weight is usually 20
000, preferably 1,000 to 10,000, more preferably 2,000 to 8,000. If it exceeds 20,000, the low-temperature fixability and the gloss when used in a full-color device deteriorate.

In the present invention, not only the polyester (i) modified with the urea bond may be used alone, but also the polyester (ii) which is not modified may be contained as a toner binder component together with this (i).
When (ii) is used in combination, the low-temperature fixability and the gloss when used in a full-color device are improved, and it is preferable to use alone. Examples of (ii) include the same polycondensates of polyol (1) and polycarboxylic acid (2) as in the polyester component (i), and preferred ones are also the same as (i). Further, (ii) may be not only an unmodified polyester but also a polyester modified with a chemical bond other than a urea bond, for example, a modified urethane bond.
It is preferable that (i) and (ii) are at least partially compatible with each other in view of low-temperature fixability and hot offset resistance. Therefore, the polyester component (i) and (ii) preferably have similar compositions. (I) and (ii) when (ii) is contained
Is usually 5/95 to 80/20, preferably 5/95.
/ 95-30 / 70, more preferably 5 / 95-25
/ 75, particularly preferably 7/93 to 20/80.
When the weight ratio of (i) is less than 5%, the hot offset resistance is deteriorated, and the heat storage stability and the low-temperature fixability are disadvantageous.

The peak molecular weight of (ii) is usually from 1,000 to
It is 10,000, preferably 1500 to 10000, and more preferably 2000 to 8000. If it is less than 1,000, the heat-resistant preservability deteriorates, and if it exceeds 10,000, the low-temperature fixability deteriorates. 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 compatibility between heat-resistant storage stability and low-temperature fixability. The acid value of (ii) is usually 0 to
120, preferably 0-50, more preferably 0-3
0. By having an acid value, it tends to be negatively charged.

In the present invention, the glass transition point (Tg) of the toner binder is usually from 35 to 85 ° C., preferably from 45 to 85 ° C.
７０70 ° C. If the temperature is lower than 35 ° C., the heat-resistant storage stability of the toner deteriorates, and if it exceeds 85 ° C., the low-temperature fixability becomes insufficient.
For unknown reasons, the dry toner of the present invention tends to have good heat-resistant storage stability even with a low glass transition point, as compared with known polyester-based toners. Temperature (TG ') at which the storage elastic modulus of the toner binder becomes 10,000 dyne / cm2 at a measurement frequency of 20 Hz.
However, it is usually 100 ° C. or higher, preferably 110 to 200 ° C. If the temperature is lower than 100 ° C., the hot offset resistance deteriorates. As the viscosity of the toner binder, the measurement frequency 20
The temperature (Tη) at which the frequency becomes 1000 poise at Hz is usually 180 ° C. or lower, preferably 90 to 160 ° C. 1
If the temperature exceeds 80 ° C., the low-temperature fixability deteriorates. That is, from the viewpoint of compatibility between low-temperature fixing property and hot offset resistance, T
G ′ is preferably higher than Tη. In other words, T
The difference between G ′ and Tη (TG′−Tη) is preferably 0 ° C. or more. It is more preferably at least 10 ° C, particularly preferably at least 20 ° C. The upper limit of the difference is not particularly limited. In addition, the difference between Tη and Tg is preferably from 0 to 100 ° C. from the viewpoint of achieving both heat-resistant storage stability and low-temperature fixability. The temperature is more preferably from 10 to 90 ° C, particularly preferably from 20 to 80 ° C.

As the coloring agent of the present invention, known dyes, pigments and magnetic powders can be used. Specifically, carbon black, Sudan Black SM, Fast Yellow-G, Benzidine Yellow, Pigment Yellow, India First Orange, Irgasin Red, Baranitoaniline Red, Toluidine Red, Carmine FB, Pigment Orange R, Lake Red 2G, Rhodamine F
B, Rhodamine B Lake, Methyl Violet B Lake, Phthalocyanine Blue, Pigment Blue, Priliant Green, Phthalocyanine Green, Oil Yellow GG, Kayaset YG, Orazol Brown B, Oil Pink OP, Magnetite, Iron Black and the like. The content of the coloring agent is usually 2 to 15% by weight, preferably 3 to 10% by weight.

Further, a wax can be contained together with the toner binder and the colorant. Known waxes can be used as the wax of the present invention, for example, polyolefin waxes (polyethylene wax, polypropylene wax, etc.); long-chain hydrocarbons (paraffin wax,
And carbonyl group-containing wax. Preferred among these are carbonyl group-containing waxes. Examples of the carbonyl group-containing wax include polyalkanoic acid esters (carnauba wax, montan wax, trimethylolpropane tribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1,18 Polyalkanol esters (tristearyl trimellitate, distearyl maleate, etc.); polyalkanoic acid amides (ethylenediamine dibehenylamide, etc.); polyalkylamides (trimellitic acid, tristearylamide, etc.) And dialkyl ketones (such as distearyl ketone). Preferred among these carbonyl group-containing waxes are polyalkanoic esters. The melting point of the wax of the present invention is usually 40 to 160 ° C, preferably 50 to 12 ° C.
0 ° C, more preferably 60 to 90 ° C. Melting point 4
Wax below 0 ° C. adversely affects heat-resistant storage stability,
Waxes exceeding 0 ° C. are liable to cause cold offset at the time of fixing at a low temperature. The melt viscosity of the wax is
As a measurement value at a temperature 20 ° C. higher than the melting point, 5 to 100
0 cps is preferred, and more preferably 10 to 100 c
ps. Waxes exceeding 1000 cps have poor effects on improving hot offset resistance and low-temperature fixability.
The content of the wax in the toner is usually from 0 to 40% by weight, preferably from 3 to 30% by weight, particularly preferably from 10 to 30% by weight.
25% by weight.

The dry toner of the present invention further comprises:
Charge control agents and glidants can also be used. Known charge control agents include nigrosine dyes, quaternary ammonium salt compounds, quaternary ammonium base-containing polymers, metal-containing azo dyes, salicylic acid metal salts, sulfonic acid group-containing polymers, fluorinated polymers, and halogen-substituted aromatics. Ring-containing polymers and the like. The content of the charge control agent is usually 0 to 5% by weight. Known fluidizers such as colloidal silica, alumina powder, titanium oxide powder, and calcium carbonate powder can be used.

The method for producing the dry toner of the present invention will be exemplified. The toner binder can be manufactured by the following method. The polyol (1) and the polycarboxylic acid (2) are heated to 150 to 280 ° C. in the presence of a known esterification catalyst such as tetrabutoxytitanate or dibutyltin oxide, and the resulting water is distilled off under reduced pressure if necessary. hand,
A polyester having a hydroxyl group is obtained. Then 40-14
At 0 ° C., the polyisocyanate (3) is reacted therewith to obtain a prepolymer (A) having an isocyanate group. Further, (A) is reacted with an amine (B) at 0 to 140 ° C. to obtain a urea-modified polyester. When reacting (3) and when reacting (A) and (B), a solvent can be used if necessary.
Examples of usable solvents include aromatic solvents (toluene, xylene, etc.); ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.); esters (ethyl acetate, etc.); amides (dimethylformamide, dimethylacetamide, etc.) and ethers And the like (e.g., tetrahydrofuran), which are inert to isocyanate (3). When the polyester (ii) not modified with a urea bond is used in combination, (ii) is produced in the same manner as the polyester having a hydroxyl group, and this is dissolved in the solution after the completion of the reaction (i) and mixed. I do.

The dry toner can be manufactured by the following methods. Spherification of pulverized toner A method in which a toner material comprising a toner binder and a colorant is melt-kneaded, and then finely pulverized is mechanically spheroidized using a hybridizer, mechanofusion, or the like. Spray dry method A method in which a toner material is dissolved and dispersed in a solvent in which a toner binder is soluble, and then the solvent is removed using a spray dry device to obtain a spherical toner. Dispersion granulation method (for example, the method described in JP-A-9-15902) After dissolving and dispersing the toner material in a solvent in which the toner binder is soluble, dispersing it in a poor solvent (for example, water) of the toner binder under stirring, Is removed to form toner particles, and after cooling, solid-liquid separation and drying are performed to obtain spherical toner.
And the like. Of these, preferred is the dispersion granulation method, and particularly preferred is the dispersion granulation method in which the poor solvent serving as the dispersed phase is an aqueous medium. Examples of the solvent for dissolving the toner binder in advance used in the dispersion granulation method in an aqueous medium include ethyl acetate, acetone, and methyl ethyl ketone. Further, if necessary, a dispersant can be used. The use of a dispersant is preferred in that the particle size distribution becomes sharp and the dispersion is stable. As a dispersant, a water-soluble polymer (polyvinyl alcohol,
Known materials such as hydroxyethyl cellulose, inorganic powders (calcium carbonate powder, calcium phosphate powder, silica fine powder, etc.) and surfactants (sodium lauryl sulfate, sodium oleate, etc.) can be used.
When a dispersant is used, the dispersant can be left on the surface of the toner particles. However, it is preferable to remove the dispersant by washing after the curing reaction from the viewpoint of charging the toner.

The dry toner of the present invention may contain iron powder,
Glass beads, nickel powder, ferrite, magnetite, and resins (acrylic resin, silicone resin, etc.)
Is mixed with carrier particles such as ferrite coated on the surface thereof and used as a developer for an electric latent image. In addition, instead of the carrier particles, friction with a member such as a charging blade can be performed to form an electric latent image.
Next, the recording material is fixed on a support (paper, polyester film, or the like) by a known hot roll fixing method, flash fixing method, or the like.

[0028]

The present invention will be further described with reference to the following examples.
The present invention is not limited to this. Hereinafter, "part" indicates "part by weight".

Example 1 (Synthesis of Toner Binder) In a reaction vessel equipped with a cooling pipe, a stirrer and a nitrogen introducing pipe, 724 parts of a 2-mol addition product of bisphenol A ethylene oxide and 276 parts of isophthalic acid were added.
Parts and 2 parts of dibutyltin oxide, and
The reaction was carried out at 30 ° C. for 8 hours and further at a reduced pressure of 10 to 15 mmHg for 5 hours, then cooled to 160 ° C., and 32 parts of phthalic anhydride was added thereto, followed by a reaction for 2 hours. Next, the mixture was cooled to 80 ° C. and reacted with 188 parts of isophorone diisocyanate in ethyl acetate for 2 hours to obtain an isocyanate-containing prepolymer (1). Next, 267 parts of the prepolymer (1) and 14 parts of isophorone diamine were added to 50 parts of the mixture.
C. for 2 hours to obtain a urea-modified polyester (1) having a weight average molecular weight of 64000. 724 parts of a bisphenol A ethylene oxide 2 mol adduct as described above,
138 parts of terephthalic acid and 138 parts of isophthalic acid are polycondensed at 230 ° C. for 6 hours under normal pressure.
The reaction was carried out at a reduced pressure of mHg for 5 hours to obtain a peak molecular weight of 230.
An unmodified polyester (a) having 0, a hydroxyl value of 55 and an acid value of 1 was obtained. Urea-modified polyester (1) 20
0 parts and 800 parts of the unmodified polyester (a) are dissolved and mixed in 2000 parts of a mixed solvent of ethyl acetate / MEK (1/1), and the toner binder (1) ethyl acetate / M
An EK solution was obtained. Part of the resultant was dried under reduced pressure to isolate the toner binder (1). Tg is 52 ° C, Tη is 123 ° C, T
G ′ was 132 ° C. (Preparation of toner) In a beaker, 240 parts of an ethyl acetate / MEK solution of the toner binder (1) and pentaerythritol tetrabehenate (melting point: 81 ° C., melt viscosity: 2)
5 cps) 20 parts, cyanine blue KRO (manufactured by Sanyo Dyestuff)
Add 4 parts, and use TK homomixer at 60 ° C for 1200
The mixture was stirred at 0 rpm and uniformly dissolved and dispersed. 706 parts of ion-exchanged water and hydroxyapatite 1 in a beaker
0% suspension (Superite 10 manufactured by Nippon Chemical Industry Co., Ltd.) 2
94 parts, sodium dodecylbenzenesulfonate 0.2
And the mixture was uniformly dissolved. Then, the temperature was raised to 60 ° C and TK
While stirring at 12,000 rpm with a homomixer, the above-mentioned toner material solution was charged and stirred for 10 minutes. The mixture was then transferred to a Kolben equipped with a stir bar and a thermometer.
The temperature was raised to 8 ° C. to remove the solvent, followed by filtration, washing and drying, followed by air classification to obtain toner particles having a particle size d50 of 6 μm. Next, 0.5 part of colloidal silica (Aerosil R972: manufactured by Nippon Aerosil) was mixed with 100 parts of the toner particles using a sample mill to obtain the toner (1) of the present invention. The practical sphericity of the toner particles was 0.96. Table 1 shows the evaluation results.

Example 2 (Synthesis of Toner Binder) In the same manner as in Example 1, bisphenol A ethylene oxide 2 mol adduct 669
Parts, 274 parts of isophthalic acid and trimellitic anhydride 2
After the polycondensation of 0 parts, isophorone diisocyanate 15
4 parts were reacted to obtain a prepolymer (2). Next, 213 parts of the prepolymer (2), 9.5 parts of isophoronediamine and 0.5 part of dibutylamine were reacted in the same manner as in Example 1 to obtain a urea-modified polyester (2) having a weight average molecular weight of 79000. Urea-modified polyester (2) 200
And 800 parts of unmodified polyester (a) were dissolved and mixed in 2000 parts of a mixed solvent of ethyl acetate / MEK (1/1) to obtain a toner binder (2) in ethyl acetate. The toner binder (2) was partially isolated by drying under reduced pressure. Tg is 52 ° C., Tη is 129 ° C., TG ′ is 15
1 ° C. (Preparation of Toner) The procedure of Example 1 was repeated except that the wax was changed to trimethylolpropane tribehenate (melting point: 58 ° C., melt viscosity: 24 cps), and the dissolution temperature and the dispersion temperature were changed to 50 ° C., and the particle size d50 was 6 μm. Of the present invention (2) was obtained. The practical spherical degree of toner particles is 0.97.
Met. Table 1 shows the evaluation results.

Comparative Example 1 (Synthesis of Toner Binder) 354 parts of 2 mol of bisphenol A ethylene oxide adduct and isophthalic acid 1
66 parts were subjected to polycondensation using 2 parts of dibutyltin oxide as a catalyst to obtain a comparative toner binder (1) having a weight average molecular weight of 8,000. Tg of the comparative toner binder (1) was 57 ° C., Tη was 136 ° C., and TG ′ was 133 ° C. (Preparation of Toner) In a beaker, 100 parts of the comparative toner binder (1), 200 parts of ethyl acetate solution, and 4 parts of cyanine blue KRO (manufactured by Sanyo Dye) were put into a beaker.
The mixture was stirred with a K-type homomixer at 12,000 rpm, and was uniformly dissolved and dispersed. Next, a toner was prepared in the same manner as in Example 1 to obtain a comparative toner (1) having a particle diameter d50 of 6 μm. The practical sphericity of the toner particles was 0.98. Table 1 shows the evaluation results.

[0032]

[Table 1]----------------------------------------------------------------------------------------------------------- HOT -------------------------------------------------------------------------- Example 1 0.38 20% 130C 180C Example 2 0.37 19% 150 ° C. 230 ° C. or higher Comparative Example 1 0.35 21% 150 ° C. 160 ° C. −−−−−−−−−−−−−−−−−−−−−−−−−−−− −−−−−−−−−− [Evaluation Method] Powder Fluidity The quietness density was measured using a powder tester manufactured by Hosokawa Micron. The quieter the toner, the better the fluidity. Heat Storage Stability After storing the toner at 50 ° C. for 8 hours, the toner was sieved with a 42 mesh sieve for 2 minutes. The residual ratio of toner having better heat resistance storage stability is smaller. Gloss development temperature (GLOSS) Fixing was evaluated using a modified machine in which the oil supply device was removed from the fixing device of a commercially available color copying machine (CLC-1; manufactured by Canon) and the oil on the fixing roll was removed. The gloss development temperature was defined as the fixing roll temperature at which the 60 ° gloss of the fixed image became 10% or more. Hot Offset Occurrence Temperature (HOT) The fixing was evaluated in the same manner as in the above GLOSS, and the presence or absence of hot offset to the fixed image was visually evaluated. The temperature of the fixing roll at which the hot offset occurred was defined as the hot offset occurrence temperature.

Example 3 (Preparation of Toner) Carbon black (Mitsubishi Kasei)
The toner binder (2) was converted to a toner in the same manner as in Example 2 except that the amount was changed to 8 parts of MA100 manufactured by Co., Ltd.
The toner (3) of the present invention having a particle size of 50 μm was obtained. The practical sphericity of the toner particles was 0.96. Table 2 shows the evaluation results.
Shown in

Example 4 (Synthesis of Toner Binder) Bisphenol A ethylene oxide 2 mol adduct 363 parts, isophthalic acid 166
Part was subjected to polycondensation in the same manner as in Example 1 to obtain a peak molecular weight of 430.
An unmodified polyester (b) having 0, a hydroxyl value of 25 and an acid value of 7 was obtained. Urea-modified polyester (2) 30
0 parts and 700 parts of unmodified polyester (b) were dissolved and mixed in 3000 parts of ethyl acetate / MEK (1/1) to obtain a solution of toner binder (4) in ethyl acetate.
A part of the mixture was dried under reduced pressure to isolate the toner binder (4).
Tg was 57 ° C., Tη was 143 ° C., and TG ′ was 172 ° C. (Preparation of toner) 300 parts of an ethyl acetate / MEK solution of toner binder (4), montan wax WE-40
(Hoechst Japan) 5 parts and carbon black (MA100 manufactured by Mitsubishi Chemical Co., Ltd.) 8 parts were used in the same manner as in Example 1, except that the particle size d50 was 6 μm.
m of the toner (4) of the present invention was obtained. The practical sphericity of the toner particles was 0.95. Table 2 shows the evaluation results.

Comparative Example 2 (Synthesis of Toner Binder) In a reaction vessel equipped with a cooling pipe, a stirrer and a nitrogen introducing pipe, 343 parts of a 2-mol adduct of bisphenol A ethylene oxide and 166 parts of isophthalic acid were added.
Parts and 2 parts of dibutyltin oxide, and
After reacting at 30 ° C. for 8 hours and further reacting under reduced pressure of 10 to 15 mmHg for 5 hours, the mixture was cooled to 80 ° C., and 14 parts of toluene diisocyanate was added in toluene, and the reaction was carried out at 110 ° C. for 5 hours. , Weight average molecular weight 9
8,000 urethane-modified polyesters were obtained. 363 parts of bisphenol A ethylene oxide 2 mol adduct and 166 parts of isophthalic acid were polycondensed in the same manner as in Example 1 to obtain an unmodified polyester having a peak molecular weight of 3,800, a hydroxyl value of 25 and an acid value of 7. 350 parts of the urethane-modified polyester and 650 parts of the unmodified polyester were dissolved and mixed in toluene, and the solvent was removed to obtain a comparative toner binder (2). Tg of the comparative toner binder (2) was 58 ° C., Tη was 145 ° C., and TG ′ was 170 ° C. (Preparation of toner) Comparative toner binder (2) 100
Part, Montan wax WE-40 (manufactured by Hoechst Japan) and 5 parts carbon black (M, manufactured by Mitsubishi Kasei Corporation)
A100) 8 parts were formed into a toner by the following method. First, Henschel mixer (FM10B, manufactured by Mitsui Miike Kakoki Co., Ltd.)
After pre-mixing using a mixer, a twin-screw kneader (Ikegai Co., Ltd.
CM-30). Then, after crushing finely using a supersonic jet crusher LabJet (manufactured by Nippon Pneumatic Industries, Ltd.), an airflow classifier (Nippon Pneumatic Industries, Ltd.)
The particles were classified by MDS-I) to obtain toner particles having a particle diameter d50 of 6 μm. Then, 0.5 part of colloidal silica (Aerosil R972: manufactured by Nippon Aerosil) was mixed with 100 parts of the toner particles by a sample mill to obtain Comparative Toner (2). The practical sphericity of the toner particles was 0.75. Table 2 shows the evaluation results.

[0036]

Table 2---------------------------------------------------------------------------------------------------------------------------MFT HOT -------------------------------------------------------------------------- Example 3 0.37 18% 110 ° C 230 ° C Implemented Example 4 0.35 8% 130 ° C 230 ° C or higher Comparative Example 2 0.27 32% 130 ° C 230 ° C −−−−−−−−−−−−−−−−−−−−−−−−−−−− −−−−−−−−−− [Evaluation Method] Powder Fluidity The quietness density was measured using a powder tester manufactured by Hosokawa Micron. The quieter the toner, the better the fluidity. Heat Storage Stability After storing the toner at 50 ° C. for 8 hours, the toner was sieved with a 42 mesh sieve for 2 minutes. The residual ratio of toner having better heat resistance storage stability is smaller. Minimum Fixing Temperature (MFT) The fixing was evaluated using a commercially available black-and-white copying machine (SF8400A; manufactured by Sharp). The minimum fixing temperature was the fixing roll temperature at which the residual ratio of the image density after rubbing the fixed image with a pad was 70% or more. Hot offset occurrence temperature (HOT) The fixing was evaluated in the same manner as in the above MFT, and the presence or absence of hot offset to the fixed image was visually evaluated. The fixing roll temperature at which hot offset occurred was taken as the hot offset occurrence temperature.

[0037]

The dry toner of the present invention has the following effects. 1. Excellent powder fluidity, excellent developability and transferability. 2. Excellent heat-resistant storage stability, and excellent both low-temperature fixability and hot offset resistance. 3. Since the color toner is excellent in glossiness and hot offset resistance, it is not necessary to apply oil to the fixing roll. 4. High transparency and excellent color tone when used as a color toner.

Claims (11)

[Claims] 1. A dry toner comprising a toner binder and a colorant, wherein the toner has a Wadell practical sphericity of 0.90 to 1.00, and the toner binder comprises a polyester (i) modified with a urea bond. A dry toner comprising: 2. The dry toner according to claim 1, wherein the ratio of the urea bond content to the urethane bond content in the modified polyester (i) is from 100/0 to 20/80 in equivalent ratio. 3. The dry toner according to claim 1, wherein the modified polyester (i) contains an alkylene oxide adduct of a bisphenol as a constituent component. 4. An unmodified polyester (i) together with the modified polyester (i).
i), and the weight ratio between (i) and (ii) is 5 / 95-8.
The dry toner according to claim 1, wherein the ratio is 0/20. 5. The peak molecular weight of (ii) is from 1,000 to 1,
5. The dry toner according to claim 4, wherein the weight of the toner is 0000. 6. The glass transition point (T) of the toner binder.
g) is 35 to 85 ° C., and the difference (TG′−Tη) between the temperature (TG ′) at which the storage elastic modulus (G ′) at a measurement frequency of 20 Hz is 10,000 dyne / cm 2 and the temperature (Tη) at which the viscosity is 1000 poise is obtained. The dry toner according to any one of claims 1 to 5, wherein (d) is not less than 0 ° C. 7. The dry toner according to claim 1, wherein the toner particles are particles formed in an aqueous medium. 8. A toner having a melting point of 50 to 120 ° C. and a melt viscosity at a temperature 20 ° C. higher than the melting point of 5 to 1000 cps together with a toner binder and a colorant, and 3 to 30% by weight in the dry toner. The dry toner according to claim 1, further comprising: 9. The dry toner according to claim 8, wherein the wax is a carbonyl group-containing wax. 10. The dry toner according to claim 1, wherein the colorant is a colorant selected from the group consisting of cyan, magenta, and yellow dyes and / or pigments. 11. The toner according to claim 1, which is used for a heat fixing toner.
11. The dry toner according to any one of items 10 to 10.