JPH11302361A - Polyester resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a binder resin that realizes a toner for developing electrostatic charge image, particularly suitable for colored image formation with good fixing characteristics and storage stability. SOLUTION: The polyester resin includes at least 20-80 mol.% of a cyclohexanedicarboxylic acid component and 20-80 mol.% of a point symmetry aromatic dicarbocylic acid component in the acid components and 70-100 mol.% of propylene glycol component in the glycol components. In this case, the resultant polyester has a glass transition temperature of >=55 deg.C, a number-average molecular weight of >=10,000 and an intrinsic viscosity, (ηsp /C) of >=0.3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording apparatus with heat fixing, mainly an electrophotographic printer such as a copying machine, a laser printer, an LED printer, and the like, a printing apparatus, or a static apparatus such as an ion flow, an ion injection and a discharge recording. In a printer using an electro-recording method, a printer using an electrostatic latent image formed by spontaneous polarization of a ferroelectric substance, and a printing device, a toner for developing an electrostatic image used for developing a latent image due to an electrostatic charge. It relates to a polyester resin suitable as a binder resin. More specifically, it is suitable for use in a fixing method that combines a heat-resistant film and a thermal head, which is excellent in color image recording quality, and has been increasingly required in recent years due to printer miniaturization, cost reduction, quick start, and power saving. The present invention relates to a polyester resin suitable as a binder resin for a toner for developing an electrostatic image.

[0002]

2. Description of the Related Art In an electrophotographic system, an electrostatic recording system or the like, a powder which develops an electrostatic latent image and is finally transferred to a base material such as a recording paper or a film to form an image is referred to as a toner. As such a toner for developing an electrostatic image, a colorant, a charge control agent, etc. are added to a binder resin, kneaded, and then pulverized and further classified, and if necessary, a fluidity modifier or the like is externally added. The particles to be produced are used. Conventionally, a styrene / acrylic copolymer resin has been mainly used as a binder resin. However, in recent years, a polyester resin having excellent low-temperature fixability and image surface gloss tends to be used in accordance with speeding up and colorization. .

[0003] The polyester resins mainly used are unsaturated polyester resins obtained mainly by condensation polymerization of aliphatic unsaturated carboxylic acids such as fumaric acid and maleic acid with diols having a bisphenol structure. A proposal for a toner using such an unsaturated polyester resin is disclosed in, for example, JP-A-47-12334. Recently, as disclosed in JP-A-4-12367, JP-A-5-165252 and the like, aromatic polycarboxylic acids such as terephthalic acid and isophthalic acid, aliphatic diols such as ethylene glycol, and cyclohexanediene are disclosed. Numerous patent proposals have been made on saturated polyester resins comprising an alicyclic diol such as methanol and the above-mentioned aromatic diol having a bisphenol structure.

[0004] Since the polyester resin has excellent gloss on the image surface after fixing, it has good color development and realizes a wide color reproduction range. In particular, when an image is recorded on a transparent film such as an overhead projector, the light transmittance is high and the quality of the projected image is high.

Generally, in a dry electrophotographic system or an electrostatic recording system, a toner obtained by developing an electrostatic latent image on a recording sheet is heated and fixed. As a heating method, a heat roll is generally used. As the material of the heat roll, silicone rubber, fluorine rubber, or the like having high releasability and elasticity is used. However, since such a rubber roll has a large heat capacity, it needs extra heat in advance, and cannot be used for a while after the power of the device is turned on. In addition, for the same reason, it is necessary to always pass an electric current to keep the heater warm, and thus there is a large problem in power saving.
In order to cope with such a problem, in some models, a method of heating with a thermal head or the like via a heat-resistant film or the like has been proposed and put into practical use.

When heated, the toner particles are melted and fixed on the recording paper, but the fused toner resin adheres partially to the heat source side as well as the recording paper, and contaminates the heat source surface. This phenomenon is called an offset phenomenon, and when the fixing process is further continued with the contaminated heat source, the contamination is transferred to the subsequent recording paper, and the quality of the recorded image is significantly reduced. Such an offset phenomenon is particularly remarkable in the fixing method in which the heat-resistant film and the thermal head are combined.

To prevent such an offset phenomenon, improvements have been made to the binder resin of the toner. It is known that such an offset phenomenon can be reduced by broadening the molecular weight distribution of the binder resin and partially crosslinking or gelling, and many patent proposals have been made.
However, these measures alone have not yet completely prevented the offset phenomenon.

Many proposals have also been made regarding improvements in the components of the toner. The toner is manufactured by kneading and dispersing a colorant, a charge control agent, and in some cases, a magnetic powder and the like into a binder resin, and externally adding a fluidizing agent and the like after pulverization and classification by a jet mill or the like. It has been proposed to reduce the offset phenomenon by blending specific waxes. For example, JP
9-164560 and JP-A-59-22866.
No. 1 proposes to mix an amide wax, a ketone wax, a specific alkyl ketene dimer or the like as an offset preventing agent. However, even with such a method, the offset phenomenon cannot be completely prevented, and the quality of the color image is remarkably reduced. In particular, only a projection image of a dark and cloudy color tone can be obtained with an overhead projector or the like.

Japanese Patent Application Laid-Open No. Sho 63-121059 proposes that fixing properties can be improved by introducing dimer acid as an acid component as a copolymer component of a polyester resin. Although fixing properties are somewhat improved by such means, increasing the copolymerization amount of dimer acid to a region where a sufficient effect can be obtained lowers the glass transition temperature of the resin and lowers the storage stability of the toner.

For example, JP-A-59-164560, JP-A-61-105562, and JP-A-59-2
9257, JP-A-59-29258, JP-A-59-198469, and JP-A-59-22345.
No. 6, JP-A-60-4947, JP-A-61-1947.
176948, JP-A-61-240248, JP-A-3-155563, JP-A-3-122
No. 664 discloses that the fixing property can be improved by similarly introducing an alkyl or alkenyl-substituted succinic acid into a copolymer component of a polyester resin. In particular, JP-A-3-155563 and JP-A-3-122664 have been proposed mainly with a view to improving fixing characteristics in a fixing method in which a heat-resistant film and a thermal head are combined. Although the fixing properties are somewhat improved by such means, the glass transition temperature is significantly reduced as in the case of dimer acid copolymerization. Further, there is a problem that odor is generated at the time of fixing the toner.

JP-A-56-1952 and JP-A-58-17452 disclose anhydrides of cyclohexenedicarboxylic acid (cyclohexylenedicarboxylic acid) or cyclohexanedicarboxylic anhydride as polyvalent carboxylic acid components, and bisphenols. There is a proposal for an electrophotographic toner composition using a polyester resin obtained from a polyhydric alcohol having a structure by a normal pressure polymerization method. Such a proposal is based on the glass transition temperature of an unsaturated polyester resin obtained by condensation polymerization of an aliphatic unsaturated carboxylic acid such as fumaric acid and maleic acid with a diol having a bisphenol structure, which is mainly used as a polyester resin for toner. And to improve the storage stability of the toner. By adding such an alicyclic polycarboxylic acid to an aliphatic polycarboxylic acid, it is possible to increase the glass transition temperature, but when an alicyclic polycarboxylic acid is used, in particular, In the normal pressure polymerization method, it is difficult to increase the molecular weight, and only a resin having a low molecular weight can be obtained, which may impair the storage stability.

[0012]

As described above, in the conventional image recording technique of performing thermal fixing using a toner for developing an electrostatic image, particularly a binder resin composition completely solving the problem at the time of thermal fixing. No product has been obtained, and the fact is that the problem is apparently solved by comprehensive engineering such as toner formulation and various devices on the fixing device side. In particular, it is satisfactory when the fixing device is limited (for example, a method of heating and fixing with a thermal head via a heat-resistant film) for the purpose of downsizing the device, quick start, energy saving, and the like. No binder resin for toner having characteristics has been obtained. In view of such circumstances, the present inventors have conducted intensive studies on polyester resins that can achieve good fixing characteristics and storage stability, and can be suitably used for a toner for developing an electrostatic image that also has excellent color image reproducibility. As a result, the present invention has been achieved.

[0013]

That is, the present invention is as follows. In the acid component, at least 20 to 80 mol% of the cyclohexanedicarboxylic acid component and 20 to 80 mol% of the point symmetric aromatic dicarboxylic acid component, and at least 70 to 100 mol% of the propylene glycol component in the glycol component.
A polyester resin having a glass transition temperature of 55
A polyester resin having a number average molecular weight of 10,000 ° C. or more and an intrinsic viscosity ηsp / c of 0.3 or more. Ethylene glycol component in the glycol component, 30
The polyester resin described above, which is contained in a range of not more than mol%. The temperature at which the melt viscosity of the polyester resin becomes 10,000 poise is Ta, and the intrinsic viscosity of the polyester resin is ηsp /
The polyester resin according to the above or the above, satisfying Ta ≦ 160 × ηsp / c + 75 when c is satisfied. Number average molecular weight of 20,000 or more and intrinsic viscosity ηsp
The polyester resin according to any one of the above-mentioned items, wherein / c is 0.4 or more. The polyester resin according to any one of the above items having an ionic group in the range of 20 to 2000 equivalents / ton. The polyester resin according to any one of the above, which is used for a binder resin of a toner for developing an electrostatic image.

Hereinafter, the present invention will be described in detail. The polyester resin of the present invention can be obtained by polycondensing a specific polyhydric carboxylic acid as an acid component and a specific polyhydric alcohol as a glycol component.

[0015] The polyester resin of the present invention comprises:
20-80 mol% of cyclohexanedicarboxylic acid component and 20-80 mol% of point-symmetric aromatic dicarboxylic acid component
including.

In the present invention, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, esters thereof and the like are used as the cyclohexanedicarboxylic acid component. These may be used alone or in combination of two or more. Further, these may be used in combination with those in which a part of the hydrogen of the cyclohexane ring is substituted with an alkyl group or the like. These may be used alone or in combination of two or more.

In the present invention, terephthalic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid,
Biphenyl dicarboxylic acid and esters thereof are preferably used. These may be used alone or in combination of two or more. Also these and isophthalic acid,
Orthophthalic acid, naphthalenedicarboxylic acid, may be used in combination with an aromatic polycarboxylic acid such as diphenic acid, in this case, isophthalic acid, orthophthalic acid is preferred

The content of the cyclohexanedicarboxylic acid component in the polyester resin of the present invention is preferably 20 to 70 mol%, more preferably 20 to 50 mol% in the acid component.
1%. When the content of the component is less than 20 mol%, the toner using such a polyester resin cannot exhibit the fixing property, and when the content exceeds 80 mol%,
The glass transition temperature of the polyester resin decreases, and the storage stability of the toner powder using the resin decreases. In the invention of the present application, the fixing characteristics mean both surface smoothness after fixing and anti-offset properties.

The content of the target aromatic dicarboxylic acid component in the polyester resin of the present invention is preferably 30 to 80 mol%, more preferably 50 to 80 mol%, in the acid component.
%. When the content of the component is less than 20 mol%, the glass transition temperature of the polyester resin is lowered, and the storage stability of the toner powder using the resin is lowered.
If it exceeds 0 mol%, the toner using such a polyester resin cannot exhibit the fixing characteristics.

In addition to the cyclohexanedicarboxylic acid component and the point-symmetric aromatic dicarboxylic acid component, the polyester resin of the present invention may further comprise an aliphatic component in the acid component, preferably at most 5 mol%, more preferably at most 2 mol%. Contains a polyvalent carboxylic acid component. As the aliphatic polycarboxylic acid component, saturated aliphatic dicarboxylic acids such as succinic acid, alkyl succinic acid, alkenyl succinic acid, adipic acid, azelaic acid, sebacic acid and dodecanedicarboxylic acid; fumaric acid, maleic acid, itaconic acid, mesacon Acid, citraconic acid, hexahydrophthalic acid, tetrahydrophthalic acid,
Unsaturated aliphatic dicarboxylic acids such as dimer acid, trimer acid and hydrogenated dimer acid, and esters thereof are preferably used. These may be used alone or in combination of two or more.

Other components other than the above-mentioned components may be contained. Examples of such components include aromatic oxycarboxylic acids such as p-oxybenzoic acid p- (hydroxyethoxy) benzoic acid; cyclohexenedicarboxylic acid; Alicyclic dicarboxylic acids such as substituted cyclohexanedicarboxylic acid and alkyl-substituted cyclohexenedicarboxylic acid; trivalent or higher polycarboxylic acids such as trimellitic acid, trimesic acid and pyromellitic acid, and esters thereof. .

The polyester resin of the present invention comprises 70 to 100 mol of a propylene glycol component in a glycol component.
%, Preferably 80 to 100 mol%, more preferably 85 to 100 mol%, particularly preferably 90 to 100 mol%.
ol%. Content of propylene glycol component is 7
When the amount is less than 0 mol%, the glass transition temperature of the polyester resin decreases, and the storage stability of the toner powder using the polyester resin decreases.

The polyester resin of the present invention is preferably 30 mol% or less, more preferably 20 mol% or less, particularly preferably 10 mol% in the glycol component.
And further contains an ethylene glycol component. The ethylene glycol component is an effective component for increasing the molecular weight of the polyester resin.

Further, the polyester resin of the present invention contains, in the glycol component, a dimer diol component in a range of 10 mol% or less and / or a polypropylene glycol component (in terms of the number of propylene glycol residues) in a range of 20 mol% or less. May be. The polyester resin containing such a component has a lower surface energy of the resin at the time of melting, and the fixing properties are more preferably improved.

Here, the dimer diol is generally derived from dimer acid. Dimer acid is a compound having 10 to 2 carbon atoms.
4, preferably about 18 dimers containing unsaturated fatty acids as a main component, and includes some monomeric acids and trimer acids. Industrially, oleic acid, elaidic acid, purified vegetable fatty acids obtained from drying oils, semi-drying oils, etc., such as tall oil fatty acids and linoleic acid, which are mixtures thereof, are used in the presence of catalysts such as montmorillonite clay. Those obtained by thermal polymerization are known. A hydrogenated dimer acid in which an unsaturated double bond is saturated by hydrogenation is also known. The dimer diol may contain some monomers and trimers similarly to the dimer acid. In addition, those in which unsaturated bonds such as a cyclohexene ring remain and those which are saturated by hydrogenation are known. In the present invention, unsaturated,
Saturation may be used, but it is preferable to use a saturated hydrogenated dimer diol.

Furthermore, the polyester resin of the present invention may contain an ethylene oxide adduct of bisphenol A and / or a propylene oxide adduct as a glycol component. Such components impart flexibility to the resin and improve viscoelastic properties when molten.

The polyester resin of the present invention may contain other components in addition to the above components. As such components, for example, the following aliphatic polyhydric alcohols, alicyclic polyhydric alcohols, aromatic polyhydric alcohols, and the like are used.

The aliphatic polyhydric alcohols include 1,3
-Propanediol, 2,3-butanediol, 1,4
-Butanediol, 1,5-pentanediol, 1,6
-Aliphatic diols such as hexanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, dimethylol heptane, 2,2,4-trimethyl-1,3-pentanediol, polyethylene glycol and polytetramethylene glycol; trimethylolethane And triols such as trimethylolpropane, glycerin and pentaerthritol, and tetraols.

The alicyclic polyhydric alcohols include 1,4
-Cyclohexanediol, 1,4-cyclohexanedimethanol, spiroglycol, hydrogenated bisphenol A, ethylene oxide adducts and propylene oxide adducts of hydrogenated bisphenol A, tricyclodecanediol, tricyclodecanedimethanol and the like.

As the aromatic polyhydric alcohols, p-xylene glycol, m-xylene glycol, o-xylene glycol, 1,4-phenylene glycol, 1,4
An ethylene oxide adduct of phenylene glycol,
Examples include bisphenol A, an alkylene oxide adduct of bisphenol A, bisphenol S, an alkylene oxide adduct of bisphenol S, bisphenol F, and an alkylene oxide adduct of bisphenol F.

Furthermore, polyester polyols such as lactone-based polyester polyols obtained by ring-opening polymerization of lactones such as ε-caprolactone can also be used.

Blocking the polar group at the terminal of the polyester resin,
For the purpose of improving the environmental stability of the toner charging characteristics, a monofunctional monomer may be introduced into the polyester resin of the present invention. Monofunctional monomers that can be used here include benzoic acid, chlorobenzoic acid, bromobenzoic acid, p-hydroxybenzoic acid, monoammonium sulfobenzoate, monosodium sulfobenzoate, cyclohexylaminocarbonylbenzoic acid, n -Dodecylaminocarbonylbenzoic acid, t-butylbenzoic acid, naphthalenecarboxylic acid, 4-
Monocarboxylic acids such as methylbenzoic acid, 3-methylbenzoic acid, salicylic acid, thiosalicylic acid, phenylacetic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, octanecarboxylic acid, lauric acid, stearyl acid, and lower alkyl esters thereof; Monoalcohols such as aliphatic alcohols, aromatic alcohols, and alicyclic alcohols can be used.

In the polyester resin of the present invention, the glass transition temperature is 55 ° C. or higher, preferably 57 ° C. or higher, more preferably 60 ° C. or higher, particularly preferably 62 ° C. or higher. When the glass transition temperature is lower than 55 ° C., the toner using such a polyester resin aggregates during handling or storage, and causes a problem in storage stability.

In the present invention, the glass transition temperature is measured by the following method using a differential scanning calorimeter. That is, 10 mg of a measurement sample is set in an aluminum pan,
After cooling to −50 ° C. with liquid nitrogen, the temperature is increased to 150 ° C. in a nitrogen atmosphere at a rate of 10 ° C./min. In the endothermic curve obtained in the process (vertical axis: temperature, horizontal axis: calorific value per unit time), the temperature at the intersection between the baseline before the endothermic peak appears and the tangent to the endothermic peak is the glass transition temperature. Tg.

The polyester resin of the present invention has a number average molecular weight of 10,000 or more, preferably 150 or more.
It is preferably at least 00, more preferably at least 20,000, particularly preferably at least 25,000. Number average molecular weight of 10,000
When the ratio is less than the above range, the fixing characteristics of the toner using the polyester resin are deteriorated.

In the present invention, the number average molecular weight is determined by gel permeation chromatography using THF as a solvent and a sample concentration of 0.02 g / 10
The measurement is performed under the conditions of ml, a flow rate of 1.0 ml / min, a temperature of 35 ° C., and an injection volume of 0.5 μl.

Further, in the polyester resin of the present invention, the intrinsic viscosity ηsp / c is at least 0.3, preferably at least 0.35, more preferably at least 0.4, particularly preferably at least 0.45. When the intrinsic viscosity is less than 0.3, the fixing characteristics of the toner using the polyester resin are deteriorated.

In the present invention, the intrinsic viscosity is determined by using a mixed solvent of phenol / 1,1,2,2-tetrachloroethane = 60/40 (weight ratio) as a solvent, Is the viscosity of η0, and the ratio of the two is η / η0 = η
When r is sp relative viscosity and ηr −1 = ηsp is specific viscosity, lo
When g (ηsp) is plotted on the vertical axis and the solution concentration c is plotted on the horizontal axis, a substantially straight line is obtained.
sp / c intrinsic viscosity.

The polyester of the present invention comprises at least a predetermined amount of a cyclohexanedicarboxylic acid component as an acid component, a predetermined amount of a point-symmetric aromatic dicarboxylic acid component and a predetermined amount or less of an aliphatic dicarboxylic acid component, and at least a predetermined amount of a glycol component. By including propylene glycol and a predetermined amount or less of ethylene glycol, the glass transition temperature, the number average molecular weight, and the intrinsic viscosity can be respectively set in the above ranges.

Further, in the polyester resin of the present invention, the softening point is preferably in the range of 80 to 150 ° C. When the softening point is lower than 80 ° C., the toner using the polyester resin tends to agglomerate during handling or storage, and the fluidity may be deteriorated particularly during long-term storage. Conversely, the softening point exceeds 150 ° C,
In some cases, the fixing characteristics of the toner using the polyester resin at a low temperature may be affected. Further, since it is necessary to heat the fixing roll to a high temperature, the material of the fixing roll and the material of the base material to be copied may be limited.

Furthermore, when the temperature at which the melt viscosity of the polyester resin becomes 10,000 poise is Ta and the intrinsic viscosity of the polyester resin is ηsp / c, the polyester resin of the present invention is more preferably Ta ≦ 160 × ηsp / c + 75. Satisfies Ta ≦ 160 × ηsp / c + 70, particularly preferably Ta ≦ 160 × ηsp / c + 70.

If the above formula is not satisfied, the fixing characteristics of the toner using the polyester resin of the present invention may be poor, which is not preferable.

The polyester resin of the present invention comprises at least a predetermined amount of a cyclohexanedicarboxylic acid component, a predetermined amount of a point-symmetric aromatic dicarboxylic acid component, and a predetermined amount or less of an aliphatic dicarboxylic acid component as an acid component. By satisfying the above formula, the above formula can be satisfied.

Further, the polyester resin of the present invention is preferably used in an amount of 20 to 2000 equivalents / ton, more preferably 30 to 2000 equivalents / ton.
It is preferable to have an ionic group of １０００1000 equivalents / ton, particularly preferably 80-300 equivalents / ton. When the content of the ionic group is less than 20 equivalents / ton, charging of the toner using such a polyester resin may become unstable, and a toner forming method using water dispersion described later can be applied. May disappear. On the other hand, if it exceeds 2,000 equivalents / ton, the moisture absorption of the toner using such a polyester resin increases, and the charge amount of the toner fluctuates due to environmental changes, which may hinder image formation.

Examples of the ionic group include a carboxyl group, a sulfonic acid group, a sulfate group, a phosphate group, and an anionic group such as an alkali metal salt, an ammonium salt, an alkyl ammonium salt, and an alkanol ammonium salt thereof; A cationic group such as a primary to tertiary amine group, preferably a carboxyl group, a carboxylate group,
Sulfonic acid groups and alkali metal sulfonic acid bases.

In order to introduce a sulfonic acid group or a sulfonic acid alkali metal base into the polyester resin of the present invention, a compound having a copolymerizable sulfonic acid group or a sulfonic acid metal base may be copolymerized. Examples of the compound include sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfophthalic acid, and 4-sulfonaphthalene-
2,7-dicarboxylic acid, 5- (4-sulfophenoxy)
Examples include isophthalic acid and the like and metal salts thereof.
In particular, when an ionic group is introduced into a molecular terminal, sulfobenzoic acid or the like and a metal salt thereof can be used. Here, as the metal salt, Li, Na, K, Mg, C
Metal salts such as a, Ba, Ni, Cu, Fe and the like can be mentioned, and Na salt is particularly preferable. Among them, it is particularly preferable to use 5-sodium sulfoisophthalic acid or sodium sulfobenzoic acid.

For the introduction of a carboxyl group, the carboxyl group remaining at the polyester terminal can be used as it is. It is also possible to introduce an acid anhydride such as trimellitic anhydride or phthalic anhydride at the end of polymerization to add a carboxyl group to the terminal. The carboxyl group thus obtained can also be neutralized with a hydroxide or carbonate of an alkali metal, ammonia, alkylamines, alkanolamines, cyclic amines, etc. to form a carboxylate group.

The polyester resin of the present invention is suitably used as a binder resin for a toner for developing an electrostatic image.
The polyester resin of the present invention may be used for the entire amount of the binder resin, but is preferably used in combination with another resin. In this case, the polyester resin of the present invention is preferably used in an amount of 25% by weight or more, more preferably 33% by weight or more, particularly preferably 40% by weight or more, and most preferably 50% by weight or more in all the binder resins.

When used in combination, the resin to be combined is preferably a polyester resin, particularly preferably about 2/3 or less, more preferably 1/2 or less, particularly preferably 1/3 or less of the polyester resin of the present invention. A polyester resin having the following number average molecular weight is preferred.

To prepare the toner for developing an electrostatic image, a coloring agent, a charge controlling agent, a fluidity modifier and the like are blended in addition to the binder resin. Can be used as needed.

As a coloring agent, a dye, a pigment, carbon black or the like may be used. These dyes, pigments, carbon black and the like may be used alone, or may be used in combination as needed. It is particularly preferable to use a dye from the viewpoint of spectral transmission characteristics.

When a pigment is used for coloring, benzidine-based, azo-based, and isosindrin-based pigments are used for yellow coloring.
Azo lake, rhodamine lake,
Quinacridone-based, naphthol-based, and diketopyrrolopyrrole-based pigments are preferably used for cyan coloring, and phthalocyanine-based pigments and indanthrene-based pigments are preferably used. When obtaining a black toner, carbon black or the like may be used. As the carbon black, thermal black, acetylene black, channel black, furnace black, lamp black and the like can be used.

When dyes are used for coloring, azo, nitro, quinoline, quinophthalone and methine dyes are used for yellow coloring, and anthraquinone, azo and xanthene dyes are used for magenta coloring and cyan coloring is used for coloring. Anthraquinone-based, phthalocyanine-based, and indoaniline-based dyes are preferably used.

The method for producing the toner for developing an electrostatic image is not particularly limited, and a colorant, a charge control agent and the like are mixed with a binder resin and then pulverized by a jet mill or the like, and a fluidity modifier or the like is externally added. A grinding method can be used. When the content of the cyclohexanedicarboxylic acid component in the polyester resin of the present invention is relatively large, the pulverizability of the resin is reduced. Therefore, it may be preferable to perform pulverization by cooling the inside of the pulverization system. As another method, a toner process by a wet process in which a colorant, a charge control agent, and the like are mixed and dispersed in a solution composed of a solvent and a binder resin, and then the solution is introduced into an aqueous system, suspended or coarsely emulsified, and classified and dried. Can be used.

When the polyester resin of the present invention has an ionic group, the resin exhibits water dispersibility (self-emulsifying property). In this case, an example of a method of emulsifying and dispersing a polyester resin in an aqueous solvent and slowly aggregating the fine particles of the polyester resin contained in the obtained dispersion to unite and grow to a size suitable for the toner, and using this to obtain a toner is exemplified. can do.

That is, the polyester resin is dissolved in a water-soluble solvent such as ketones, alcohols, tetrahydrofuran, cellosolves, and dioxane, and then water is added thereto. You can get the body. Slow coagulation is possible by adding an appropriate electrolyte into the aqueous dispersion system and controlling the temperature. In particular, a method of adding an amino group-containing ester composed of an amino alcohol and a carboxylic acid, hydrolyzing the ester in the system by raising the temperature, adjusting the pH, and the like to generate an amine salt of the carboxylic acid is a method of forming a moderately cohesive zone Is preferable as a method for leading to Particles containing pigment (carbon black) can be produced if water-dispersed fine particles such as pigment and carbon black coexist in the slow aggregation region. It is also possible to obtain toner particles colored with a dye by allowing the dye to coexist at the time of emulsification, and it is also possible to post-color the obtained colorless particles by a high-temperature dispersion dyeing method.

According to this method, the average particle diameter D is 2 to 1.
A toner for electrostatic charge development comprising substantially spherical particles having particles of 0 μm and a sphericity of 0.7 or more occupying 70% or more of the whole can be obtained. Since it is substantially spherical, it is highly suitable for a non-magnetic one-component developing method.

The toner using the polyester resin of the present invention has a surface energy of 5
0 dyn / cm or less, surface temperature during fixing is 60 to 200
It is preferable that the toner is fixed by a fixing device in the range of ° C. Here, the material of the fixing member is not particularly limited, but is preferably a member mainly used in a fixing method using a combination of a heat-resistant film and a thermal head, and has a heat-resistant base material such as polyimide, polyamide, or polyamide-imide. A heat-resistant film obtained by subjecting a film to a surface treatment with a fluorine resin, a silicone resin, or the like. Similarly, the present invention can be applied to a member used in a fixing device using an elastic roll which has been widely used conventionally.

[0059]

According to the present invention, a polyester resin having a melt viscosity of 10
It is the result of finding that good fixing characteristics can be realized when Ta ≦ 160 × ηsp / c + 75 is satisfied, where Ta is the temperature at which 000 poise is reached, and ηsp / c is the intrinsic viscosity of the polyester resin.

When discussing the fixing characteristics, it is easily presumed that the relationship between the surface energy of the fixing member and the surface energy of the toner resin is important. However, the range that can be interpreted by surface energy is limited to static phenomena, and the fixing process, which is actually a dynamic phenomenon, cannot be interpreted or specified only by surface energy.

The fixing operation can be interpreted as the following process. That is, 1. The heated fixing member comes into contact with the toner particles electrostatically attached to the recording paper, and the toner particles are heated by heat conduction. 2. Pressure is simultaneously applied to the toner resin layer that has reached the molten state, and the toner layer is fixed on the recording paper. 3. The fixing member separates from the toner layer.

In actual equipment, generally, when the fixing temperature is increased, fixing of the toner to the paper is started from a certain temperature, and when the temperature is further increased, an offset phenomenon occurs. This temperature range, that is, a wide fixing temperature range is required.

The present inventors have found that the melting viscosity of the toner resin is generally about 10 before the toner resin is fixed on the recording paper under normal pressure.
It was found that it was necessary to reduce it to about 000 poise. The temperature at which such melt viscosity is reached is defined as Ta. Melt viscosity generally has a positive correlation with the molecular weight of the resin. On the other hand, in the fixing operation, it is important that the offset phenomenon does not occur when the fixing member separates from the toner resin layer. In the offset phenomenon, as described above, the relationship between the surface energy of the toner resin layer and the surface energy of the fixing member should be defined, but the viscoelastic properties of the molten toner resin layer are also defined at the same time. Should be. Here, the viscoelastic property is qualitatively understood as the cohesive force of a molten resin.
It is known that the viscoelastic properties of a resin largely depend on the copolymer composition of the resin, the molecular weight, the presence or absence of branching, but the present inventors preferably use the intrinsic viscosity of the resin as a representative value, It has been found that when the right side of the expression Ta ≦ 160 × ηsp / c + 75 derived from the above is Ta or more, good offset resistance is exhibited. In other words, only when a low viscosity at a level sufficient to be fixed on the recording paper is realized at a molecular weight equal to or higher than a predetermined value, a wide fixing temperature range, that is, between a low minimum fixing temperature and a high offset occurrence temperature,
It is considered that good fixing characteristics achieving both surface smoothness and offset resistance are realized.

The polyester resin of the present invention not only realizes the above-mentioned properties relating to fixing, but also satisfies a wide range of other properties required for the toner, for example, the storage stability of the toner. It is particularly important in the present invention that the acid component contains at least a specific amount of a cyclohexanedicarboxylic acid component and a point-symmetric aromatic dicarboxylic acid component, and the glycol component contains at least a specific amount of propylene glycol.

The polyester resin having an ionic group is required for producing a substantially spherical toner in a wet process. Spherical toner is said to be highly suitable for recent non-magnetic one-component development systems and the like, and in the present invention, which is mainly intended to be compatible with small color machines, non-magnetic toners are a powerful developing mechanism in small color machines. It is considered that it is important to make the toner composition suitable for magnetic one-component development particularly to enhance the value of the invention.

[0066]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Production Examples and Examples of the present invention, but the present invention is not limited thereto. Production Example of Polyester Resin In an autoclave equipped with a thermometer and a stirrer, 81 parts by weight of terephthalic acid 83 parts by weight of 1,4-cyclohexanedicarboxylic acid 167 parts by weight of propylene glycol 0.09 parts by weight of antimony trioxide were charged. The mixture was heated at 180 ° C. for 180 minutes to perform a transesterification reaction. Next, the temperature of the reaction system was raised to 245 ° C., and the reaction was continued for 180 minutes at a system pressure of 1 to 10 mmHg to obtain a copolymerized polyester resin (A1).
The copolymer composition ratio by NMR analysis was 49 mol% of terephthalic acid in the acid component, 51 mol% of 1,4-cyclohexanedicarboxylic acid in the acid component, and 100 mol% of propylene glycol in the glycol component.

In the production examples of the copolymerized polyester resin (A1), the copolymerized polyester (A2) to the copolymerized polyester (A2) were prepared in the same manner except that the copolymerized components were changed as shown in Table 1.
(A16) was obtained. Table 1 shows the characteristic values of the obtained copolymerized polyester resins (A1) to (A16).

[0068]

[Table 1]

The symbols in Table 1 are as follows. TPA Terephthalic acid IPA Isophthalic acid NDC 2,6-Naphthalenedicarboxylic acid 1,4-CHDA 1,4-Cyclohexanedicarboxylic acid 1,2-CHDA 1,2-Cyclohexanedicarboxylic acid D-SA Dodecenyl succinic acid SIP 5-Sodium sulfoisophthalic acid TMA trimellitic acid PG propylene glycol EG ethylene glycol NPG neopentyl glycol CHDM cyclohexanedimethanol BPA-PO Propylene oxide adduct of bisphenol A (average molecular weight 400)

Here, each characteristic value was measured by the following method. 1) Weight-average molecular weight and number-average molecular weight The weight-average molecular weight and the number-average molecular weight were measured by gel permeation chromatography (manufactured by Shimadzu Corporation), and the column was Shodex KF800P, KF8 manufactured by Showa Denko.
0M, KF802, KF801, THF as solvent, sample concentration 0.02g / 10ml, Shimadzu RID6A as detector, flow rate 1.0m
1 / min, temperature 35 ° C, injection volume 0.5 μl
It measured on condition of. 2) Glass transition temperature Measured by the following method using a differential scanning calorimeter (manufactured by Shimadzu Corporation). That is, 10 mg of a measurement sample was set in an aluminum pan, cooled to −50 ° C. with liquid nitrogen, and then heated to 150 ° C. in a nitrogen atmosphere at a rate of 10 ° C./min. Endothermic curve obtained in the process (vertical axis: temperature,
In the graph, the temperature at the intersection of the baseline before the endothermic peak and the tangent to the endothermic peak was taken as the glass transition temperature Tg. 3) Temperature at which the melt viscosity becomes 10,000 poise (Ta) The melt viscosity of the polyester resin is measured at intervals of 5 ° C. using a flow tester CFT-500C manufactured by Shimadzu Corporation, and the vertical axis is the logarithm of the melt viscosity and the horizontal axis is the temperature. It was determined from the plot from which it was taken. 4) Intrinsic viscosity ηsp / c A mixed solvent of phenol / 1,1,2,2-tetrachloroethane = 60/40 (weight ratio) is used as a solvent, and the viscosity η of the solution and the viscosity of the quasi-solvent are η0. Ratio η / η0 =
When ηr is the sp relative viscosity and ηr-1 = ηsp is the specific viscosity,
When log (ηsp) is plotted on the ordinate and the solution concentration c is plotted on the abscissa, an almost straight line is obtained. The viscosity when this straight line is c = 0 is defined as ηsp / c intrinsic viscosity. 5) COOH group equivalent Dissolve 1.0 g of the resin in 30 ml of chloroform, and use phenolphthalein as an indicator for 0.1N KO.
The solution was titrated with an H solution and converted to a COOH group equivalent. 6) S
O ₃ Na group equivalent The molten resin is poured into a mold, and the thickness is 3 mm and the diameter is 30 m
m was used as a sample, and the content of sulfur element was quantified using a fluorescent X-ray analyzer manufactured by Shimadzu Corporation, and this was converted to SO ₃ Na group equivalent. 7) Specific gravity 0.3 ml of ion exchanged water in a 1-liter measuring cylinder
A liter was placed therein, and a small piece of 0.5 g of the resin was placed therein.
To this, a saturated aqueous solution of calcium chloride was added little by little, and the mixture was stirred and left for a while.When the small pieces of the resin stopped without floating or settling in the aqueous solution, the specific gravity of the aqueous solution was measured with a float type hydrometer. This value was taken as the specific gravity of the resin.

Example 1 95 parts by weight of a copolymerized polyester resin (A1) was roughly pulverized by a chopper mill, and preliminarily mixed with 5 parts by weight of a copper phthalocyanine cyan pigment Heliogen Blue S7084 (BASF) in a ball mill. Then, the mixture was kneaded with a hot roll mill, cooled, and coarsely pulverized again. Next, the resultant was finely pulverized by a jet mill and then classified, and further subjected to a surface treatment with hydrophobic silica fine powder Aerosil using a Henschel mixer to obtain a cyan toner (T1) having an average particle diameter of 8.5 μm.

Examples 2 to 9 and Comparative Examples 1 to 6 In Example 1, the copolymerized polyester resin (A1) was replaced with the copolymerized polyester resin (A2) to (A15).
Except that the toner (T
2) to (T15) were obtained.

Example 10 100 parts by weight of a copolyester resin (A6), 80 parts by weight of methyl ethyl ketone, 40 parts by weight of tetrahydrofuran, UV absorber Seesorb 706 (manufactured by Cipro Kasei)
3 parts by weight, magenta dye C.I. I. Disperse thread 6
5 parts by weight of 0 conc cake (manufactured by Mitsui Toatsu Chemicals) was charged into a separable flask and dissolved at about 80 ° C. Next, the temperature was lowered to 70 ° C., 250 parts of water at 68 ° C. was added, and an aqueous dispersion of a copolymerized polyester resin having a particle diameter of about 0.1 μm was obtained by a phase inversion self-emulsification method. Further, the obtained aqueous microdispersion was placed in a distillation flask and distilled until the fraction temperature reached 103 ° C., and after cooling, water was added to increase the solids concentration to 25%.
%. In a four-necked 1-liter separable flask equipped with a thermometer, a condenser, and a stirring blade, 400 parts by weight of the obtained aqueous dispersion of the copolymerized polyester (solid content: 100
Parts by weight) and heated to 70 ° C. Next, 100 parts by weight of water in which 15.8 parts by weight of dimethylaminoethyl methacrylate were dissolved was added, and stirring was continued for 8 hours. As a result, the copolymer having a particle diameter on the order of submicrons, which was present in the aqueous dispersion of the copolymerized polyester, was united and grew, and the average particle diameter was 6.5 μm and the diameter D was 0.5D to 2D.
95% by weight of particles having a particle size in the range of D, average sphericity of 0.98, and 97% of particles having a sphericity of 0.7 or more.
Of polyester resin particles having a substantially spherical shape. The obtained polyester resin particles were dehydrated and washed using a suction funnel, and dried with a fluidized drier to obtain a magenta toner (T16). Here, the average particle diameter and the particle diameter distribution were determined by the Coulter counter method, and the sphericity was determined by image processing (500 or more measured particles) of an SEM photograph of the particles with an image analyzer V10 (manufactured by Toyobo Co., Ltd.).

Example 11 In Example 10, the dye was changed to Neopen Yellow 075.
A yellow toner (T17) was obtained in the same manner as in Example 10, except that 5 parts by weight (manufactured by BASF) was used.

Example 12 In Example 10, the dye was changed to Neopen Cyan FF42.
A cyan toner (T18) was obtained in the same manner as in Example 10, except that the weight was changed to 8 parts by weight of 38 (manufactured by BASF).

Example 13 Example 10 was repeated except that the dye was changed to 10 parts by weight of Oil Black 860 (manufactured by Orient Chemical) and 5 parts by weight of T-77 (manufactured by Hodogaya Chemical).
A black toner (T19) was obtained in the same manner as described above.

Comparative Example 7 95 parts by weight of a copolymerized polyester resin (A14) was roughly pulverized by a chopper mill, and this was copper phthalocyanine cyan pigment Heliogen Blue S7084 (manufactured by BASF).
5 parts by weight, 2 parts by weight of ethylene / propylene copolymer wax having a softening point of 110 ° C., and 3 parts by weight of stearyl ketene dimer were preliminarily mixed by a ball mill, kneaded by a hot roll mill, cooled, coarsely pulverized again, and then jetted. After finely pulverizing with a mill, the resultant was classified to obtain a cyan toner (T20) having an average particle size of 8.3 μm.

Example 14 50 parts by weight of the copolymerized polyester resin (A1) and 45 parts by weight of the copolymerized polyester resin (A16) were coarsely pulverized by a chopper mill, and this was crushed with a copper phthalocyanine cyan pigment Heliogen Blue S7084 (BASF). 5 parts by weight), premixed in a ball mill, kneaded in a hot roll mill, cooled, coarsely pulverized again, then finely pulverized in a jet mill, then classified, and further finely divided in a Henschel mixer. Perform surface treatment with powder Aerosil,
A cyan toner (T21) having an average particle size of 7.5 μm was obtained.

Examples 15 to 22 In Example 14, the copolymerized polyester resin (A1) was used.
With the copolymerized polyester resin (A2) to (A
Except having changed to 9), the toners (T22) to (T29) were obtained in the same manner as in Example 14.

(Image Fixing Test) A ball mill was charged with 5 parts by weight of the toners obtained in Examples 1 to 22 and Comparative Examples 1 to 7 and 95 parts by weight of a ferrite carrier F-100 (manufactured by Powder Tech). The mixture was stirred for about 15 minutes to obtain a developer. This developer was charged into a testing machine of a commercially available dry electrophotographic copying machine from which a fixing device was removed, and an electrostatic image was formed on PPC paper and developed. The obtained unfixed image was fixed by the prototype fixing device shown in FIG. The symbols used in the prototype fixing device shown in FIG. 1 are as follows. 1: Thermal head 2: Heat resistant film 3: Drive roll 4: Recording paper 5: Pressure roll

The surface temperature of the thermal head is 80.degree.
Variable between 0 ° C. Low-resistance PTFE with conductive filler dispersed on the contact surface with toner
A 25 μm-thick coated polyimide film was used. The surface energy of the coating surface of the heat-resistant film was 12.5 dyn / cm. The image was fixed by raising the temperature of the thermal head by 5 ° C. from 80 ° C., and the fixing state and the state of occurrence of offset were observed. The fixing state was evaluated by attaching a cellophane tape to an image portion having a toner thickness of about 5 μm or more at a constant pressure, peeling the cellophane tape at a constant speed, and determining whether toner adhered to the cellophane tape. The recording paper feed speed was about 10 sheets per minute in the A4 vertical direction. An image was formed and fixed on a transparent polyester film by setting a heat roll temperature to a temperature of fixing start temperature + 10 ° C., and projected and observed by an overhead projector. The results are shown in Tables 2 to 5. Further, the obtained toner is placed in a 50 ml glass container, and 5
The blocking property of the toner after leaving it to stand at 0 ° C. for 96 hours was evaluated. The results are shown in Tables 2 to 5. Where ○
Indicates that the toner did not block and maintained good powder properties as a toner, and X indicates that blocking occurred and the powder was lightly fused to form a lump.

[0082]

[Table 2]

[0083]

[Table 3]

[0084]

[Table 4]

[0085]

[Table 5]

From Tables 2 to 5, it can be seen that the toners obtained in Examples 1 to 22 have good fixing characteristics in which the interval between the lower limit fixing temperature and the offset occurrence temperature is wide in a fixing device in which a heat-resistant film and a thermal head are combined. And the blocking resistance was also good. On the other hand, in the toners obtained in Comparative Examples 1 to 5 and 7, the interval between the fixing lower limit temperature and the offset occurrence temperature is narrow, and it is difficult to control the fixing temperature in an actual device, and a good fixed image can be obtained. Did not. The toner obtained in Comparative Example 6 had poor blocking resistance.

(Color Image Forming Test) For color printing,
A four-color YMCK positive image (landscape photograph), which is color-separated and halftone-converted with 175 lines, is used as a document, and the four-color toners (T16) to (T19) obtained in Examples 10 to 13 are used.
Using the above-described tester, the fixing temperature is set to an intermediate value between the average value of the fixing start temperatures of the four colors and the average value of the offset occurrence temperatures. First, a yellow image is output, and a magenta image and then a cyan image are formed on the obtained image. , And black to form a full-color image. The obtained image shows a clear color although some misregistration occurs, shows good fixing characteristics without offset even in a portion where toners of different colors overlap, and also preferably produces a secondary color. Met. Similarly, a full-color image was formed on a transparent film and observed with an overhead projector, but a clear projected image could be obtained.

[0088]

As is clear from the above description, according to the polyester resin of the present invention, the fixing lower limit temperature and the offset can be particularly improved in a fixing device combining a heat-resistant film and a thermal head capable of power saving and quick start. It is possible to provide a toner for developing an electrostatic image, which has a wide interval from the generation temperature, exhibits good fixing characteristics in a wide temperature range, can provide a high-quality image, and has excellent storage stability. Further, since there is no need to add a release agent or the like to the toner, the transparency of the resin layer is excellent, and the surface smoothness of the fixed image is excellent, so that a toner excellent in color image reproducibility can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic view of an apparatus used in an image fixing test of toners obtained in Examples and Comparative Examples of the present invention.

[Explanation of symbols]

 1: Thermal head 2: Heat resistant film 3: Drive roll 4: Recording paper 5: Pressure roll

Claims (6)

[Claims] 1. An acid component comprising at least 20 to 80 mol% of a cyclohexanedicarboxylic acid component and 20 to 80 mol% of a point-symmetric aromatic dicarboxylic acid component, and at least 70 to 80 mol% of a glycol component.
A polyester resin containing 100 mol%, having a glass transition temperature of 55 ° C. or more, a number average molecular weight of 10,000 or more, and an intrinsic viscosity ηsp / c of 0.3 or more. 2. The polyester resin according to claim 1, wherein an ethylene glycol component is contained in the glycol component in a range of 30 mol% or less. 3. The polyester resin has a melt viscosity of 1000.
3. The polyester resin according to claim 1, wherein Ta ≦ 160 × ηsp / c + 75, where Ta is the temperature at which 0 poise is obtained and ηsp / c is the intrinsic viscosity of the polyester resin. 4. 4. The polyester resin according to claim 1, wherein the number average molecular weight is 20,000 or more and the intrinsic viscosity ηsp / c is 0.4 or more. 5. The polyester resin according to claim 1, having an ionic group in the range of 20 to 2000 equivalents / ton. 6. The polyester resin according to claim 1, which is used for a binder resin of a toner for developing an electrostatic image.