JP3356164B2 - Non-magnetic one-component toner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner in a non-magnetic one-component developing method used in a field such as electrophotography.

[0002]

2. Description of the Related Art Electrophotography is disclosed in U.S. Pat. No. 2,297,691.
No., JP-B-42-23910 and JP-B-43-43.
As variously disclosed in, for example, Japanese Patent No. 24748, an electrostatic latent image is generally formed on a photoreceptor containing a photoconductive material by various means, and then the latent image is developed as a powder image with toner. If necessary, the powder image is transferred to paper or the like, and then fixed by heating, pressurizing, or solvent vapor.

Further, in recent years, an electrostatic latent image of a document is formed by exposing with a spectral light, and is developed with a color toner of each color to obtain a colored copy image, or a copy image of each color is superimposed. A color copying method for obtaining a full-color copied image has been put to practical use, and color toners of yellow, magenta, cyan, etc., in which dyes and / or pigments of each color are dispersed in a binder resin, have been produced as color toners used in the method. ing.

As a method for developing toner, a non-magnetic one-component developing method has recently been adopted in order to reduce the size of the apparatus, simplify maintenance, respond to colorization, and the like.
As the non-magnetic one-component developing method, a contact developing method such as a touch-down method and a flying developing method such as a projection method are known.In any case, a non-magnetic toner is coated on a developing sleeve by an applying member such as an elastic blade. The point is to apply evenly with a thin layer.

[0005]

However, in the non-magnetic one-component developing method, generally, a method for imparting chargeability to toner is as follows.
Since it is inevitable that the toner is in contact with the thinned toner and the developing sleeve or the elastic blade as described above, the mechanical stress on the toner is extremely large,
In particular, during continuous use, frictional heat generated often causes toner to aggregate or solidify. Such a phenomenon ultimately causes fusion of the toner aggregates to the developing sleeve and the elastic blade, and appears as a fatal image defect.

In order to solve this problem, there has been proposed a method in which an external additive such as fine-particle silica is applied to the surface of the toner particles to make the toner particles non-adhesive and to improve the aggregation of the particles. However, in this method, the initial characteristics cannot be maintained such that the external additive fine particles fall off or scatter from the toner surface or are buried in the toner particles due to long-term stirring in the developing device. Sex was not enough. As a result, it is considered that the above-mentioned problem needs to be improved mainly in terms of the properties of the binder resin for the toner in the non-magnetic one-component toner, and a drastic solution has been desired.

In the case of a color toner, it is necessary that the above-mentioned problem be solved as a resin and that the required properties such as gloss and transparency of an image be satisfied.
The present invention has been made in view of the above situation, and has been made in order to solve the problem. The object of the present invention is to provide a non-magnetic material having excellent aging stability and durability as a result by having the following performance. An object of the present invention is to provide an image forming method using a component developing method.

[0008] Agglomeration of toner is less likely to occur. Low fusion to photoreceptor, developing sleeve, elastic blade, etc. Good fluidity and high toner transportability. Aggregation and fusion of the toner hardly occur even in a high temperature and high humidity environment. No offset phenomenon occurs during fixing, and fixing strength is high. Excellent in glossiness and transparency as a color toner. Little change in image quality even during continuous use or long-term use.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in order to achieve the above object, and as a result, in an image forming method using a non-magnetic one-component developing method, a polyester resin having a specific thermal characteristic is used as a binder resin. It has been found that the above object can be satisfied when a fine particle additive is provided on the surface of the toner, and the present invention has been achieved. That is, the gist of the present invention is to provide a toner conveying member, a toner layer thickness regulating member and a roller-shaped toner replenishing auxiliary member, and the replenishing auxiliary member and the toner conveying member, and the toner layer thickness regulating member and the toner conveying member are respectively provided. A non-magnetic one-component toner used in an image forming method of developing a latent image by contacting and supplying a toner thinned using a contacting device to a latent image carrier, wherein the toner is colored. Agent and a polyester resin, wherein the polyester resin is a polyvalent alcohol.
When the glass transition temperature (Tg) is plotted on the xy coordinates with the glass transition temperature (Tg) as a variable on the x-axis and the softening point (Sp) as a variable on the y-axis.
A non-magnetic one-component toner having physical properties within a range surrounded by a straight line represented by the formula, and further comprising at least one type of fine particle additive on the surface of the toner particles. Exist.

Formula Sp = 4Tg-110 Formula Sp = 4Tg-170 Formula Sp = 90 Formula Sp = 120 Hereinafter, the present invention will be described in detail. The non-magnetic toner used in the present invention includes a colorant, a charge control agent, a polyester resin, and the like as constituent components.

As the colorant contained in the non-magnetic toner according to the present invention, any suitable pigment or dye is used. For example, carbon black, lamp black, iron black, ultramarine, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa Yellow G, rhodamine-based dyes, chrome yellow, quinacridone, benzidine yellow, rose bengal, triallylmethane-based dyes,
Any conventionally known dyes and pigments such as anthraquinone dyes, monoazo and disazo dyes and pigments can be used alone or in combination. These colorants are used in the binder resin 10
It is preferably used in an amount of 0.5 to 20 parts by weight, more preferably 2 to 10 parts by weight, based on 0 parts by weight.

As the charge control agent, all known charge control agents can be used. For example, there are a nigrosine dye, an amino group-containing vinyl copolymer, a quaternary ammonium salt compound, a polyamine resin and the like for positive charging, and a metal containing chromium, zinc, iron, cobalt and aluminum for negative charging. Metal azo dyes, salts of salicylic acid or alkyl salicylic acid with the above-mentioned metals, metal complexes and the like are known. The amount used is preferably 0.1 to 25 parts by weight, more preferably 1 to 100 parts by weight of the resin.
~ 15 parts by weight is good. In this case, the charge control agent may be added to the resin, or may be used in the form of being attached to the surface of the toner particles.

[0013] Of these charge control agents, taking into account the ability to impart charge to the toner and the adaptability to the color toner (the charge control agent itself is colorless or light-colored and there is no color tone hindrance to the toner), it is used for positive chargeability. Is preferably a vinyl copolymer containing an amino group and / or a quaternary ammonium salt compound, and a metal salt or a metal complex of salicylic acid or alkylsalicylic acid such as chromium, zinc, or aluminum is preferably used for negative chargeability.

Among these, as the amino group-containing vinyl copolymer, for example, a copolymer resin of an amino acrylate such as N, N-dimethylaminomethyl acrylate or N, N-diethylaminomethyl acrylate with styrene, methyl methacrylate or the like is used. No. Examples of the quaternary ammonium salt compound include a salt-forming compound of tetraethylammonium chloride, benzyltributylammonium chloride and naphtholsulfonic acid, and the like. For a positively chargeable toner, the amino group-containing vinyl copolymer described above and the quaternary ammonium salt compound may be added alone or in combination.

As the metal salt or metal complex of salicylic acid or alkyl salicylic acid, a chromium or zinc complex of 3,5-ditert-butylsalicylic acid is particularly preferable among various known substances. In order to improve the dispersibility and compatibility of the colorant and the charge controlling agent in the toner, a preliminary dispersion treatment, that is, a so-called master batch treatment may be performed in advance by kneading with a resin.

On the other hand, the polyester resin used in the present invention comprises a polyhydric alcohol and a polybasic acid, and if necessary, at least one of the polyhydric alcohol and the polybasic acid is a trifunctional or higher polyfunctional component (crosslinked). Component) is obtained by polymerizing a monomer composition containing the same. In the above, examples of the dihydric alcohol used in the synthesis of the polyester resin include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol,
1,4-butanediol, neopentyl glycol,
1,4-butenediol, 1,5-pentanediol,
Examples thereof include diols such as 1,6-hexanediol, bisphenol A alkylene oxide adducts such as bisphenol A, hydrogenated bisphenol A, polyoxyethylenated bisphenol A, and polyoxypropylene bisphenol A, and the like. Among these monomers, it is particularly preferable to use a bisphenol A alkylene oxide adduct as a main component monomer.
The adduct of 7 is preferred.

Examples of the trihydric or higher polyhydric alcohol involved in the crosslinking of polyester include sorbitol and
1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, sucrose, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol , 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene, and the like.

On the other hand, polybasic acids include, for example, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, azelaic acid Examples thereof include acids, malonic acids, anhydrides of these acids, lower alkyl esters, alkenylsuccinic acids or alkylsuccinic acids such as n-dodecenylsuccinic acid and n-dodecylsuccinic acid, and other divalent organic acids.

Examples of the tribasic or higher polybasic acid involved in the crosslinking of the polyester include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid,
1,2,4-cyclohexanetricarboxylic acid, 2,5
7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, tetra (methylenecarboxyl) methane, Examples thereof include 1,2,7,8-octanetetracarboxylic acid, anhydrides thereof, and others.

These polyester resins can be synthesized by a usual method. Specifically, the reaction temperature (1
Conditions such as 70 to 250 ° C.) and reaction pressure (5 mmHg to normal pressure) may be determined according to the reactivity of the monomer, and the reaction may be terminated when predetermined physical properties are obtained. As described above, in these polyester resins, their softening points (S
Those having p) and a glass transition temperature (Tg) within the ranges represented by the above formulas (1) and (2) are used, and these are specifically shown in FIG. As apparent from FIG. 1, the Sp of the polyester resin according to the present invention is 90 to 120 ° C.
The range of Tg is, for example, 50 to 50 when the softening point is 90 ° C.
65 ° C. and 60-75 ° C. when the softening point is 130 ° C. In this case, when Sp is lower than the above range, an offset phenomenon at the time of fixing is likely to occur, and when Sp is higher than the above range, fixing energy increases, and glossiness and transparency tend to deteriorate with color toner, which is not preferable. . Also, T
If the value of g is lower than the above-mentioned range, the toner tends to cause agglomeration and fixation. Sp can be adjusted mainly by the molecular weight of the resin, and preferably has a number average molecular weight of 2000 to 20,000, more preferably 3000 to 1.
2000 is recommended. The Tg can be adjusted mainly by selecting a monomer component constituting the resin. Specifically, the Tg can be increased by using an aromatic polybasic acid as a main component as an acid component. That is, among the above-mentioned polybasic acids, phthalic acid, isophthalic acid, terephthalic acid, 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid and the like, and anhydrides and lower alkyl esters thereof are used. It is desirable to use it as a main component.

The Sp of the polyester resin is JIS K72.
The measurement was performed using a flow tester described in No. 10 and K6719. Specifically, as shown in FIG. 2, about 1 g of a sample 3 was prepared by using a flow tester (CFT-500, manufactured by Shimadzu Corporation) at a heating rate of 3 ° C./min. 30k with plunger 1 of area 1cm2 while heating with
A load of g / cm 2 is applied, and the material is extruded from a die 4 having a hole diameter of 1 mm and a length of 10 mm. Thus, a plunger stroke-temperature curve as shown in FIG. 3 is drawn, and when the height of the S-shaped curve is h, the temperature corresponding to h / 2 is set as the softening point.

Tg was measured by a differential scanning calorimeter (DS).
C). On the other hand, if the acid value of the polyester resin is too high, it is generally difficult to obtain a stable and high charge amount, and the charge stability at high temperature and high humidity tends to be deteriorated.
mg / g or less, more preferably 30 KO
It is preferable to prepare it so as to be Hmg / g or less. As a method for adjusting the acid value within the above range, other than a method of controlling the addition ratio of the alcohol-based and acid-based monomers used in the resin synthesis, for example, the acid monomer component is previously converted to a lower alkyl ester by a transesterification method. And a method of neutralizing residual acid groups by adding a basic component such as an amino group-containing glycol to the composition, but not limited thereto. Needless to say, it can be adopted. Incidentally, the acid value of the polyester resin is in accordance with JIS K00.
It is measured according to the method of No. 70. However, when the resin is difficult to dissolve in the solvent, a good solvent such as dioxane may be used.

Further, as the resin of the toner according to the present invention, other known resins can be mixed and used as long as the performance of the present invention is not impaired. For example, a polyester resin, a styrene acrylic resin, an epoxy resin, a butyral resin, a styrene butadiene resin other than the present invention are exemplified. The non-magnetic toner according to the present invention contains at least one type of fine particle additive on the surface of the particle. These are mainly intended to improve the adhesiveness, cohesiveness, fluidity, and the like of the toner particles, and to improve the triboelectric chargeability and durability of the toner. Specific examples thereof include organic and inorganic fine particles having an average primary particle diameter of 0.001 to 5 μm, and particularly preferably 0.002 to 3 μm, whose surface may be treated. Examples thereof include polyvinylidene fluoride and polytetrafluoroethylene. Such as fluorine resin powder, fatty acid metal salts such as zinc stearate and calcium stearate, resin beads mainly containing polymethyl methacrylate and silicone resin, minerals such as talc and hydrotalcite, silicon oxide, and aluminum oxide And metal oxides such as titanium oxide, zinc oxide and tin oxide.

Among these, fine particles of silicon oxide are more preferable, and fine particles of silicon oxide whose surface is subjected to a hydrophobic treatment are particularly preferable. As a method of hydrophobization, for example, a method of reacting or physically adsorbing silicon oxide fine particles with an organic silicon compound such as hexamethyldisilazane, trimethylsilane, dimethyldichlorosilane or the like, and chemically treating the particles is exemplified. The addition ratio of these fine particle additives to the non-magnetic toner is preferably from 100: 0.01 to 10 by weight, and more preferably from 100: 0.05 to 5 by weight.

In the non-magnetic toner according to the present invention,
As other components, any known substance such as a release agent such as low molecular weight polyethylene or polypropylene can be contained. The average particle diameter of the toner is preferably 3 to 20 μm, more preferably 5 to 20 μm.
15 μm is more preferred

The non-magnetic toner according to the present invention can be produced by various production methods including a conventionally known method, and the following examples are given as general production methods. The resin, the charge control substance, the colorant, and any additives that are added as needed are uniformly dispersed with a Henschel mixer or the like. The dispersion is melt-kneaded with a kneader, extruder, roll mill or the like. The kneaded material is roughly pulverized by a hammer mill, a cutter mill, or the like, and then finely pulverized by a jet mill, an I-type mill, or the like. The finely pulverized material is classified by a dispersion classifier, a zigzag classifier or the like. In some cases, silica or the like is dispersed in the classified material using a Henschel mixer or the like.

As a completely different method from the above-mentioned production method, for example, production by a suspension polymerization method can be mentioned. As described above, the non-magnetic toner according to the present invention uses a polyester resin having a softening point and a glass transition temperature within a specific range as a resin, in other words, a polyester resin having a high glass transition temperature even at a low softening point, and the surface of the toner particles. By containing the fine particle additive, the strength against mechanical stress can be increased, the cohesion and fusing property of the toner can be suppressed, and the durability can be improved.

The toner of the present invention is useful for forming an image by a non-magnetic one-component developing system in electrophotography. Hereinafter, an image forming method using the toner of the present invention will be described. This image forming method is based on a non-magnetic one-component developing method in electrophotography in which a thinned toner is supplied to a latent image carrier to develop a latent image. Note that the toner thinning usually includes a toner conveying member, a toner layer thickness regulating member, and a toner replenishing auxiliary member, and the replenishing auxiliary member and the toner conveying member, and the toner layer thickness regulating member and the toner conveying member respectively. This is performed using the abutting device.

The image forming method of the present invention will be described in more detail with reference to the drawings. FIG. 4 is an explanatory view showing an example of a developing device using a non-magnetic one-component toner which can be used for performing the image forming method of the present invention. In the drawing,
Toner 1 of the present invention built in toner hopper 12
1 is forcibly brought to a sponge roller (toner replenishment auxiliary member) 9 by a stirring blade 10, and toner is supplied to the sponge roller 9. And the sponge roller 9
Is transported to the toner conveying member 7 by rotating the sponge roller 9 in the direction of the arrow.
The toner is conveyed by friction and electrostatically or physically attracted, the toner transport member 7 is strongly rotated in the direction of the arrow, and a uniform thin toner layer is formed by a steel elastic blade (toner layer thickness regulating member) 8 and friction is caused. Charges. Thereafter, the latent image is transported to the surface of the electrostatic latent image carrier 6 which is in contact with the toner transport member 7, and the latent image is developed. The electrostatic latent image is obtained by, for example, charging the organic photoreceptor with a DC voltage of 500 V and exposing the same.

[0030]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the scope of the invention. In addition, in each of Examples and Comparative Examples, “parts” simply means “parts by weight”. Production of Polyester Resins 1-4 The materials having the compositions shown in Table 1 were placed in a glass three-liter four-necked flask, fitted with a thermometer, a stainless steel stirring rod, a falling condenser, and a nitrogen inlet tube. Under nitrogen flow, first half 200 ℃ normal pressure, second half 2
The reaction proceeded while stirring at 20 ° C. under reduced pressure. The state of the reaction was tracked while measuring the softening point, and the reaction was stopped when a predetermined physical property was reached, followed by cooling to room temperature to obtain each polyester resin.

[0031]

[Table 1]

In Table 1, alcohol and acid components are represented by abbreviations and symbols, and they represent the following raw material names. Diol A: polyoxypropylene (2.2)
-2,2-bis (4-hydroxyphenyl) propane diol B: polyoxyethylene (2.2)-
2,2-bis (4-hydroxyphenyl) propane EG: ethylene glycol TPA: terephthalic acid IDSA: isododecenyl succinic acid TMAA: trimellitic anhydride The physical properties of the above polyester resins are shown in Table 2.

[0033]

[Table 2]

Production of Comparative Polyester Resins 5 to 8 The reaction was carried out in exactly the same manner as in the above-mentioned production method of the polyester resin except that the composition materials shown in Table 3 below were used. The reaction was allowed to proceed while measuring the softening point. When the reaction reached a predetermined physical property, the reaction was stopped and then cooled to room temperature to obtain each polyester resin.

[0035]

[Table 3]

In Table 3, alcohol and acid components are represented by abbreviations and symbols, and they have the same meanings as in Table 1 except for the following. Diol C: hydrogenated bisphenol A FA: fumaric acid Table 4 shows the physical property values of these polyester resins.

[0037]

[Table 4]

Examples 1 to 7 and Comparative Examples 1 to 4 Table 5 lists toner compositions of Examples 1 to 7 and Comparative Examples 1 to 4.

[0039]

[Table 5]

The method for producing the toner was as follows. Melt and knead each toner material with a kneader,
After cooling, the mixture was roughly pulverized using a hammer mill, and then finely pulverized by a fine pulverizer using an air jet method. The resulting fine powder was classified to select a particle size of 5 to 20 μm to obtain a toner. Each of the volume average particle diameters measured by the Coulter counter was in the range of 10 ± 0.5 μm.
To 100 parts of the toner, 0.5 part of fine-particle silica (Aerosil R-972, manufactured by Nippon Aerosil Co., Ltd.) was externally added using a Henschel mixer.

These toners were evaluated by a real test using the developing device shown in FIG. When the photosensitive member is a positively chargeable toner (Example 1 and Comparative Example 1)
Indicates the case where the selenium drum is a negatively chargeable toner (Examples 2 to 5).
7 and Comparative Examples 2 to 4) used an organic photoconductor, and all were developed by a reversal development method. In this case, in order to confirm the durability of the toner, a running test of about 20,000 sheets was performed, and the aggregation and fusion state of the toner were observed with a microscope.
The change in image density was measured using a reflection densitometer, and the change in image quality was visually observed. The fixing is performed while supplying oil using a silicon roller, the fixing speed is 120 mm / sec, the fixing temperature is 180 ° C., and the fixing strength of the toner is determined by folding the solid portion of the copy after fixing into two and adhering the toner. The state was observed, and the fixability was evaluated.

Table 6 summarizes the evaluation results. According to this, the image forming method using the non-magnetic one-component toner of the present invention can obtain a high-quality and stable image, and since there is no aggregation or fusion of the toner, the durability as the toner is also improved. Excellent. Further, the fixing property of the toner is good. On the other hand, according to the comparative example, durability is poor, such as remarkable image quality resulting from fusion of the toner to the developing sleeve and the elastic blade, and a problem in fixing strength.

[0043]

[Table 6]

[0044]

The effects obtained by the present invention are as follows. According to the non-magnetic one-component toner of the present invention, (1) even when used continuously for a long period of time, the initial characteristics are maintained, the toner does not aggregate, the chargeability does not change, and toner filming does not occur. Also, the fixing characteristics are good. (2) A high-quality copy that is not affected by environmental changes such as aging or high temperature and humidity can be obtained. (3) Excellent transparency and fastness, and good hue
A color toner having saturation can be obtained and can be applied to color electrophotography. As described above, according to the present invention, a stable and high-quality image can be easily obtained, so that the present invention is extremely useful industrially.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the softening point of a polyester resin according to the present invention and the effective range of glass transition temperature.

FIG. 2 is a schematic sectional view showing a central portion of the flow tester.

FIG. 3 is a plunger stroke (displacement) -temperature curve of the flow tester.

FIG. 4 is a schematic explanatory view showing an example of a developing device useful for carrying out the method of the present invention using the toner of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plunger 2 Cylinder 3 Sample 4 Die 5 Die holder 6 Electrostatic latent image carrier 7 Toner conveying member 8 Elastic blade (toner layer thickness regulating member) 9 Sponge roller (toner replenishment auxiliary member) 10 Stirring blade 11 Toner 12 Toner hopper

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hirofumi Oda 370 Yenzura, Chigasaki-shi, Kanagawa Mitsubishi Chemical Corporation Chigasaki Office (56) References JP-A-62-45622 (JP, A) JP-A-4-4 40470 (JP, A) JP-A-4-37661 (JP, A) JP-A-4-19754 (JP, A) JP-A-2-269364 (JP, A) JP-A-2-66564 (JP, A) JP-A-2-82 (JP, A) JP-A-1-116646 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 9/08

Claims (1)

(57) [Claims] 1. A toner conveying member, a toner layer thickness regulating member, and a roller-shaped toner replenishing auxiliary member, wherein the replenishing auxiliary member and the toner conveying member, and the toner layer thickness regulating member and the toner conveying member contact each other. the toner obtained by thin layer using the apparatus are a non-magnetic one-component toner used in an image forming method for developing a latent image by supplying in contact with the latent image carrier, the toner is at least a colorant and containing polyester resin, the polyester resin is a multi
When the glass transition temperature (Tg) is plotted on the xy coordinate with the glass transition temperature (Tg) as a variable on the x-axis and the softening point (Sp) as a variable on the y-axis, it is composed of only a polyhydric alcohol and a polybasic acid component. A non-magnetic one-component toner having physical properties within a range surrounded by a straight line, and further comprising at least one type of fine particle additive on the surface of the toner particles. Formula Sp = 4Tg-110 Formula Sp = 4Tg-170 Formula Sp = 90 Formula Sp = 120