JPH11282211A - Electrostatic charge image developer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain excellent developing property and safeness for long-term printing and to decrease production of fog by incorporating a positive electrification toner comprising a specified positive charge controlling agent and a negative charge controlling resin. SOLUTION: This developer contains a positive electrification toner described below. The toner contains a charge controlling material comprising a positive charge controlling agent and a negative charge controlling resin. The total amt. of the positive charge controlling agent and the negative charge controlling resin is 2 to 10 pts.wt. to 100 pts.wt. of the binder resin. The weight ratio of the positive charge controlling agent to the negative charge controlling resin is 100:1 to 3:1. The product of the acid value (KOH mg/g) of the negative charge controlling resin and its content to 100 pts.wt. of the binder resin is 1 to 50. The positive charge controlling agent is preferably used as a master batch with a resin having solubility with the binder resin of the toner, preferably with the binder resin of the toner. As for the negative charge controlling resin, any material can be used as far as it can uniformly produce negative charges on the toner surface and does not cause spent of a charge imparting material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developer for an electrostatic image containing a positively or negatively charged toner.

[0002]

2. Description of the Related Art Conventionally, there has been known a technique in which positive and negative charge control agents are used in combination with toner in order to obtain excellent image characteristics. For example, JP-A-54-34243 and JP-A-59-232360 disclose toners containing positive and negative charge control agents.
In Japanese Patent Application Laid-Open No. Sho 5 (1993), there is disclosed a toner in which one charge control agent is contained in toner particles and the other is present on the surface of the particles.
JP-A-7-64250 reports a toner in which any charge control agent is present on the surface of toner particles.

However, in such a toner, a phenomenon called so-called spent occurs in which the negatively-charged control agent present on the toner surface or appears is attached to the charge-imparting material. However, there is a problem in that the charging ability of the charge providing material is reduced due to long-term printing, causing fogging and scattering of the toner. Further, when the above toner is used as a positively chargeable toner, the chargeability of the charge imparting material is improved by long-term printing, but the charge level of the toner becomes too high, so that the developing property such as image density is rather increased. Is reduced. Furthermore, in the above-mentioned conventional negative charge control agent,
Since heavy metal components such as Cr and Co are contained, there is a problem in safety.

Japanese Patent Application Laid-Open No. 63-184762 discloses a technique in which a resin having a negative charge property (a negative charge control resin) is used alone as a charge control agent.
Such a toner cannot completely solve the above-mentioned problem, and the image density of a copied image is significantly reduced due to long-term printing.

[0005]

DISCLOSURE OF THE INVENTION The present invention is excellent in developability over a long press life, and has less fogging.
An object of the present invention is to provide a developer for electrostatic charge which is excellent in safety.

[0006]

According to the present invention, there is provided an electrostatic image developer comprising at least a binder resin, a colorant, and a toner comprising at least two kinds of charge control materials, wherein the charge control material is positively charged. A control agent and a negative charge control resin, and the total content of the positive charge control agent and the negative charge control resin is 2 to 10 parts by weight based on 100 parts by weight of the binder resin.
Parts by weight, the content ratio by weight of the positive charge control agent and the negative charge control resin is 100: 1 to 3: 1, and the acid value (KOHmg / g) of the negative charge control resin and the content relative to 100 parts by weight of the binder resin (Part by weight) is from 1 to 50. The present invention relates to a developer for an electrostatic image containing a positively chargeable toner.

According to the present invention, there is further provided a developer for an electrostatic image containing at least a binder resin, a colorant, and a toner comprising at least two kinds of charge control materials, wherein the charge control material is a positive charge control agent and a negative charge control material. The total content of the positive charge control agent and the negative charge control resin is 2 to 10 parts by weight with respect to 100 parts by weight of the binder resin, and the content weight ratio of the positive charge control agent and the negative charge control resin is 1 : 100 to 1: 3, and the product of the acid value (KOH mg / g) of the negative charge control resin and the content (parts by weight) with respect to 100 parts by weight of the binder resin is 35 to 280. The present invention relates to a developer for an electrostatic image containing a conductive toner.

In the present invention, a specific amount of the positive charge control agent and the negative charge control resin is contained in the toner, and the acid value (KOH mg / g) of the negative charge control resin and the binder resin
By defining the product of the content (parts by weight) with respect to 0 parts by weight, it is possible to provide a developer for electrostatic charge which has excellent developability over a long printing run, has less fogging, and is excellent in safety. It became possible to do. In this specification,
The term “load control resin” refers to a resin that functions to promote negative charging of the toner.

The positive charge control agent used in the present invention is not particularly limited as long as it is generally used as an additive capable of imparting a positive charge to the toner. Agents. For example, a nigrosine dye, a triphenylmethane-based compound, a quaternary ammonium salt-based compound and the like are mentioned, and a quaternary ammonium salt-based compound is particularly preferred as the positive charge control agent for more effectively achieving the object of the present invention. . In addition, two or more such positive charge control agents can be selected and used. The quaternary ammonium salt may be selected from those having no deliquescence, low solubility in water and low hygroscopicity, and preferably has a melting point of 100 ° C or higher and a decomposition point of 200 ° C or higher.

When a quaternary ammonium salt compound is used as the positive charge control agent, the preferable range of the amount of the compound exposed on the toner surface is determined by the weight ratio of the compound to the toner containing the compound. When the toner to be charged is a positively chargeable toner, the content is 0.1 to 0.8% by weight, preferably 0.2 to 0.5% by weight. If the exposure amount is less than 0.1% by weight, the charge point or charged surface on the toner surface is small, so that the charge control of the toner becomes unstable, and the background fog occurs, and the image density tends to be reduced. On the other hand, if the content exceeds 0.8% by weight, the dispersibility of the compound is reduced, so that the charge amount of the toner in a high humidity environment is greatly reduced, and the fog of the base is easily generated. On the other hand, when the toner to be manufactured is a negatively-chargeable toner, 0.001 to
It is 0.2% by weight, preferably 0.01-0.05% by weight. If the exposure amount is less than 0.001% by weight, the effect of stabilizing the charge by the charge control agent having the opposite polarity to that of the toner is reduced, so that the toner charge amount increases and the image density tends to decrease with printing durability. is there. On the other hand, if the content exceeds 0.2% by weight, the charging action by the charge control agent having the opposite polarity to that of the toner becomes too strong.

Further, when a nigrosine dye is used as the positive charge control agent, the preferable range of the amount of the compound exposed to the toner surface is the weight ratio of the compound to the toner containing the compound. When the toner is a positively chargeable toner, the content is 0.004 to 0.035% by weight, preferably 0.01 to 0.02% by weight. Exposure is 0.0
When the amount is less than 04% by weight, the charge point or the charged surface on the toner surface is small, so that the charge control of the toner becomes unstable and the background fog is generated, and the image density is apt to be lowered. On the other hand, when the content exceeds 0.035% by weight, the dispersibility is reduced, so that the toner charge amount under a high-humidity environment is greatly reduced, and the background fog is easily generated. On the other hand, when the toner to be manufactured is a negatively chargeable toner, 0.00
0.01 to 0.0075% by weight, preferably 0.001 to
0.005% by weight. Exposure is 0.0001% by weight
If the amount is smaller, the effect of stabilizing the charge by the charge control agent having the opposite polarity to that of the toner is reduced, so that the toner charge amount tends to increase and the image density tends to decrease with printing. On the other hand, when the content exceeds 0.0075% by weight, the charging action by the charge control agent having the polarity opposite to that of the toner becomes too strong, so that the charge amount of the toner is reduced and the background fog is easily generated.

In this specification, the exposure amount is a value measured according to the following. A predetermined amount of the toner and the solvent (see Table 1) are put into a 50 cc screw tube to elute the positive charge control agent exposed on the toner surface under predetermined conditions (see Table 1). After filtering this solution, the absorbance of the eluted positive charge control agent was measured by a spectrophotometer, and the amount of surface exposure was determined from the relationship between the previously measured amount of the positive charge control agent and the absorbance.

[0013]

[Table 1]

The above positive charge control agent is desirably used as a master batch with a resin compatible with the binder resin of the toner, preferably with the toner binder resin. By using the positive charge control agent as a master batch in this manner, the dispersibility of the control agent in the toner is improved, and stable chargeability can be obtained even when the environment changes. Most preferably, a styrene resin or a polyester resin is used together with the toner binder resin as the resin of the master batch.

[0015] Specifically, the positive charge control agent masterbatch comprises a resin and a positive charge control agent in a weight ratio of about 9: 1 to 5: 5.
, Kneaded, cooled,
Obtained by grinding. If the content of the positive charge control agent in the masterbatch is less than 10% by weight or more than 50% by weight, the effect of the masterbatch on the positive charge control agent cannot be easily obtained. When a masterbatch is used as a positive charge control agent in this way, the masterbatch is contained so that the positive charge control agent in the masterbatch falls within the content range of a positive charge control agent described later.

As the negative charge control resin that can be used in the present invention, a material that can uniformly generate a negative charge on the toner surface and has no spent on the charge imparting material can be used.
Although those generally used in conventional electrophotographic toners may be used, as the negative charge control resin for more effectively achieving the object of the present invention, 2-acrylamido-2-methylpropanesulfonic acid and , Styrene and / or α
-A copolymer containing methylstyrene as a main component (hereinafter simply referred to as AMPS) is particularly preferred.

For example, when AMPS is used as the negative charge control resin, the acid value of the negative charge control resin can be arbitrarily set by changing the content of 2-acrylamido-2-methylpropanesulfonic acid. ~ 6
0 KOHmg / g, more preferably 15 to 40 KO
Hmg / g, an even more preferred range is 25-35 KOH
mg / g. When the acid value is less than 6 KOHmg / g, the charge point on the toner surface decreases, and
If it exceeds 0 KOH mg / g, the dispersion in the binder resin becomes non-uniform, so that the charge amount of the toner decreases in any case.

Acid value of the negative charge control resin (KOHmg / g)
The product of the content and the content (parts by weight) with respect to 100 parts by weight of the binder resin is 1 to 50, preferably 3 to 41, and more preferably 5 to 35 for the positively chargeable toner. When the product is smaller than 1, the negative charge point on the toner surface is reduced, so that the effect of the charge stability by the negative charge control resin is reduced, and the toner charge amount increases with the endurance of printing and the image density decreases. It will be a bit. On the other hand, if it is larger than 50, the dispersion in the binder resin becomes non-uniform or the influence of the negative charge by the negative charge control resin becomes strong, so that the toner charge amount decreases in any case. On the other hand, for negatively chargeable toner, the product is 35 to 28.
0, preferably 60-240, more preferably 85-2
20. When the product is smaller than 35, the charged point on the toner surface decreases, and when the product is larger than 280, the dispersion in the binder resin becomes non-uniform. Fog tends to occur.

The preferred range of the weight average molecular weight (Mw) in such a negative charge control resin is 2000 to 1500.
0, a more preferable range is 3000-10000,
An even more preferred range is from 3500 to 7000. M
When w is smaller than 2,000, the toner charge amount under a high humidity environment is greatly reduced. On the other hand, Mw is 150
If it is larger than 00, the dispersion in the binder resin becomes non-uniform, and it becomes difficult to obtain a desired toner charge amount.

The negative charge control resin can be obtained by a known polymerization method, for example, a solution polymerization method, an emulsion polymerization method, a suspension polymerization method, a bulk polymerization method, etc., but from the viewpoint of productivity and safety, the solution weight is controlled. It is preferable to synthesize by employing a legal method. For example, when synthesizing the above-mentioned AMPS, the weight ratio of 2-acrylamido-2-methylpropanesulfonic acid used to styrene and / or α-methylstyrene is 2:98 to 20:80, preferably 5: 95-
15:85, more preferably 5:95 to 10:90. If the proportion of 2-acrylamido-2-methylpropanesulfonic acid is lower than the above range, a desired acid value cannot be obtained, the charge point on the toner surface decreases, and if the ratio is high, the dispersion in the binder resin becomes uneven. Therefore, in any case, the toner charge amount decreases.

As an initiator which can be used in synthesizing the copolymer containing 2-acrylamido-2-methylpropanesulfonic acid and styrene and / or α-methylstyrene as main components, lauroyl par Known initiators such as oxides and azobisisobutyronitrile can be used in arbitrary amounts to obtain a desired resin molecular weight. In addition, as a solvent in the case of employing a solution polymerization method, a known organic solvent conventionally used in a solution polymerization method, for example, toluene, xylene, methanol, or the like can be used.

The total amount of the positive charge control agent and the negative charge control resin used in the present invention is 2 to 10 parts by weight, preferably 3 to 10 parts by weight, based on 100 parts by weight of the binder resin.
7 parts by weight are contained. If the total amount of the two is less than 2 parts by weight, the charge point or charged surface of the toner surface is small, so that the charge control of the toner becomes unstable and the background fog occurs, and the image density is reduced. On the other hand, when the amount exceeds 10 parts by weight, the dispersibility of each charge control material is reduced, so that the amount of toner charge in a high humidity environment is greatly reduced, and base fog occurs. Hereinafter, 100 parts by weight of the binder resin means a total amount of 100 parts by weight of the toner binder resin and the resin of the master batch when a master batch with the resin is used as the positive charge control agent.

The weight ratio of the positive charge control agent to the negative charge control resin is 100: 1 to 3: 1 for the positively chargeable toner.
1, preferably 50: 1 to 5: 1, more preferably 2
0: 1 to 5: 1, and 1: 100 for negatively chargeable toner.
１ ： 1: 3, preferably 1:50 to 1: 5, more preferably 1:20 to 1: 5. When the ratio of the positive charge control agent in the positively chargeable toner exceeds the above range, the effect of stabilizing the charge by the negative charge control resin having the opposite polarity to that of the toner is reduced, so that the toner charge amount increases with printing durability. The image density tends to decrease. Conversely, if the ratio falls below the above range, the effect of charging by the negative charge control resin having the polarity opposite to that of the toner becomes too strong, so that the toner charge amount is reduced and the background fog is liable to occur. On the other hand, if the ratio of the negative charge control resin exceeds the above range, the effect of stabilizing the charge by the positive charge control agent having the opposite polarity to that of the toner is reduced. Increases and the image density tends to decrease. Conversely, if the ratio falls below the above range, the effect of charging by the positive charge control agent having the opposite polarity to that of the toner becomes too strong, so that the toner charge amount is reduced and the background fog is liable to occur.

In the present invention, two or more kinds of the above-mentioned positive and negative charge control materials are used, and their contents and content ratios are defined, so that the negative charge control materials during printing can be used. It is considered that since the spent material is not spent, the charging ability of the charged member can be maintained for a long time. Further, since the above charge control materials do not contain heavy metal components such as Cr and Co, the developer of the present invention is excellent in safety.

The toner contained in the developer of the present invention comprises at least the above positive charge control agent, negative charge control resin, binder resin and colorant.

As the binder resin that can be used in the present invention, styrene copolymer resins, polyester resins, epoxy resins, etc., which have been conventionally used as binder resins for toners, can be arbitrarily used.

Examples of the styrene monomer constituting the styrene copolymer resin according to the present invention include styrene, α-
Methylstyrene, p-methylstyrene, p-tert-
Styrene-based monomers such as butylstyrene and p-chlorostyrene and derivatives thereof can be used.

The monomers copolymerized with the styrene monomer include methyl methacrylate and n-methacrylic acid.
Propyl, isopropyl methacrylate, n-methacrylate
-Butyl, isobutyl methacrylate, t-methacrylate
Butyl, n-pentyl methacrylate, isopentyl methacrylate, neopentyl methacrylate, methacrylic acid 3
-(Methyl) butyl, hexyl methacrylate, octyl methacrylate, nonyl methacrylate, decyl methacrylate, undecyl methacrylate and dodecyl methacrylate; alkyl methacrylate; methyl acrylate, n-propyl acrylate, isopropyl acrylate; N-butyl acrylate, isobutyl acrylate, t-butyl acrylate, n-pentyl acrylate, isopentyl acrylate, neopentyl acrylate, 3- (methyl) butyl acrylate, hexyl acrylate, octyl acrylate, nonyl acrylate , Decyl acrylate,
Alkyl acrylates such as undecyl acrylate and dodecyl acrylate; unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid and maleic acid; acrylonitrile, maleic ester, itaconic ester, vinyl chloride, vinyl acetate, benzoic acid Vinyl monomers such as vinyl, vinyl methyl ethyl ketone, vinyl hexyl ketone, vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether can be used. Preferably, methacrylic acid alkyl ester (alkyl group having 1 to 17 carbon atoms) and acrylic acid alkyl ester (alkyl group having 1 to 17 carbon atoms) can be used.

As the polyester resin that can be used in the present invention, the following polyester resin A or polyester resin B can be used alone or in combination.

The polyester resin A is obtained by polycondensing an etherified diphenol with a divalent carboxylic acid or an acid anhydride thereof or a lower alkyl ester thereof, or by mixing an etherified diphenol with a divalent ether. A carboxylic acid or an acid anhydride thereof or a lower alkyl ester thereof;
It is obtained by polycondensation of a trivalent or higher polyhydric carboxylic acid, an acid anhydride thereof, a lower alkyl ester thereof, or a trivalent or higher polyhydric alcohol.

As the etherified diphenols constituting the polyester resin A, polyoxypropylene (2,
2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3,3) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (6) -2,2-bis Examples thereof include polyoxypropylene bisphenol A such as (4-hydroxyphenyl) propane and polyoxyethylenated bisphenol A such as polyoxyethylene (2,0) -2,2-bis (4-hydroxyphenyl) propane. .

As the divalent carboxylic acid component, 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, malonic acid, alkenyl succinic acid or alkyl succinic acid, and anhydrides or lower alkyl esters of these acids can be mentioned.

The trivalent or higher carboxylic acid component includes, for example, 1,2,4-benzenetricarboxylic acid (trimellitic acid), 1,2,5-benzenetricarboxylic acid,
5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-
Dicarboxyl-2-methyl-2-methylenecarboxypropane, 1,2,4-cyclohexanetricarboxylic acid, tetra (methylenecarboxyl) methane, 1,2,2
7,8-octanetetracarboxylic acid, pyromellitic acid,
Examples thereof include anhydrides and lower alkyl esters.

Examples of the trihydric or higher polyhydric alcohol include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol,
2,4-butanetriol, 1,2,5-pentatriol, glycerol, 2-metalpropanetriol,
2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-
Trihydroxymethylbenzene and the like can be mentioned.

In particular, polyoxyethylenated bisphenol A and polyoxypropylene-modified bisphenol A are used in combination as etherified diphenols, divalent aromatic carboxylic acids are used as divalent carboxylic acids, and trivalent or higher carboxylic acids are used. Polyester resin A obtained by using a trivalent aromatic carboxylic acid as the polyvalent carboxylic acid is preferred.

The polyester resin A has a softening point of 1
A toner having a temperature of from 05 to 112 ° C. is used, whereby the low-temperature fixability of the toner can be improved. Softening point is 105 ℃
If the temperature is lower than 110 ° C., the toner is easily crushed, and the redot reproducibility is lowered. If the temperature is higher than 112 ° C., the effect of improving the fixing property is insufficient.

As the polyester resin B, the same etherified diphenols, divalent carboxylic acids and trivalent or higher polycarboxylic acids similar to those used as the constituent monomers of the polyester resin A are used.

In particular, polyoxyethylenated bisphenol A and polyoxypropylene-modified bisphenol A are used in combination as etherified diphenols, and divalent aromatic carboxylic acids and divalent aliphatic carboxylic acids are used as divalent carboxylic acids. Polyester resin B obtained in combination and using a trivalent aromatic carboxylic acid as a trivalent or higher polycarboxylic acid is preferred.

The polyester resin B has a softening point of 1
Use the one of 50 to 155 ° C. If the softening point is lower than 150 ° C., offset tends to occur. If the softening point is higher than 155 ° C., the fixability of the toner is impaired.

Polyester resin A and polyester resin B
Is used in a weight ratio in the range of 75:25 to 40:60, so that the spread of the toner due to crushing at the time of fixing is small, the dot reproducibility is excellent, and a wider fixable area can be secured. Also, excellent dot reproducibility can be maintained during double-sided image formation (when the sheet passes through the fixing roll twice). When the proportion of the polyester resin A is less than the above range, the low-temperature fixability becomes insufficient and a wide fixable area cannot be secured. When the proportion of the polyester resin B is less than the above range, the toner is crushed at the time of fixing and the dot reproducibility is reduced.

The coloring agent used in the present invention is not particularly limited, and coloring agents conventionally used in electrophotography can be used, and the following can be exemplified.

As the black pigment, carbon black,
Copper oxide, manganese dioxide, aniline black, activated carbon,
Ferrite, magnetite, etc. can be used.

Examples of the yellow pigments include graphite, zinc yellow, cadmium yellow, yellow iron oxide, mineral fast yellow, nickel titanium yellow, navels yellow, naphthol yellow S, banza yellow G, banza yellow 10G, benzidine yellow G, and benzidine. Yellow GR, quinoline yellow lake, permanent yellow NCG, tartrazine lake, and the like can be used.

Examples of the red pigment include red yellow lead, molybdenum orange, permanent orange GTR, pyrazolone orange, vulcan orange, indaslen brilliant orange RK, benzidine orange G, indaslen brilliant orange GK, bengala, cadmium red, red lead, permanent Red 4R, Risor Red,
Pyrazolone red, watching red, lake red C, lake red D, brilliant carmine 6B, eosin lake, rhodamine lake B, alizarin lake,
Brilliant Carmine 3B, permanent orange GT
R, Vulcan Fast Orange GG, Permanent Red F4RH, Permanent Carmine FB and the like can be used.

As the blue pigment, navy blue, cobalt blue, alkali blue lake, Victoria blue lake,
Phthalocyanine blue or the like can be used.

The content of these coloring agents is not particularly limited, but is usually from 1 to 20 parts by weight, preferably from 3 to 15 parts by weight, per 100 parts by weight of the binder resin.

The toner contained in the developer of the present invention may contain other additives such as an anti-offset agent and magnetic powder.

The offset preventive agent is not particularly limited, and for example, polyethylene wax, carnauba wax, sasol wax, rice wax, candelilla wax, jojoba oil wax, beeswax and the like can be used. The amount of such wax added is
0.5 to 7 parts by weight, preferably 2 to 5 parts by weight, based on 100 parts by weight of the binder resin. This is because if the amount is less than 0.5 part by weight, the effect of the addition becomes insufficient, and if it exceeds 7 parts by weight, heat resistance, chargeability, and filming property to the photoreceptor decrease.

When the above polyester resin A or B is used as the toner binder resin, it is preferable to use an oxidized polyolefin wax. The polyester resin B has a network structure of trivalent or higher polycarboxylic acids contained as a constituent component thereof, and particularly has a low compatibility with low molecular weight polyethylene or polypropylene which is usually used as a release agent, and has an offset phenomenon. In addition, the release agent released in the pulverizing process during production is mixed into the toner as fine particles, which are fused to the photoconductor (filming) or adhered to the carrier (spent). This is because a problem arises.

Since the oxidized polyolefin wax effective for the polyester resins A and B has a polar group (carboxyl group) in its structure, the polyester resin A and the polyester resin B each having a polar group at the terminal thereof.
And excellent offset effect can be obtained without causing the problem of the release agent adhering to the photoreceptor or the like.

As the oxidized polyolefin wax,
For example, commercially available sun wax E-2
50P (acid value 19.5: manufactured by Sanyo Chemical Industries), sun wax E-310 (acid value 15: manufactured by Sanyo Chemical Industries), high wax 4052E (acid value 20: manufactured by Mitsui Petrochemical Industry), high wax Oxidized polyethylene wax such as 4053E (acid value 25: manufactured by Mitsui Petrochemical Industries), High Wax 4202E (acid value 17: manufactured by Mitsui Petrochemical Industry), Viscol TS-200 (acid value 3.5: Sanyo Chemical Industries) Oxidation type polypropylene wax such as the one manufactured by K.K.

The oxidized polyolefin wax is used in an amount of from 1.0 to 6.0 based on 100 parts by weight of the binder resin of the toner.
It is added in a range of 0 parts by weight. If the addition amount is less than 1.0 part by weight, a sufficient offset prevention effect cannot be obtained, and
When the amount is more than the weight part, the resin is not sufficiently compatible with the binder resin and filming or the like on the photoreceptor is likely to occur.

Known magnetic powders can be used. For example, ferrite, magnetite, iron and the like can be used alone or in combination. The content of the magnetic powder is suitably about 1 to 20 parts by weight based on 100 parts by weight of the binder resin.

The toner contained in the developer of the present invention uses the above-mentioned positive charge control agent, negative charge control resin, binder resin, colorant and other desired additives, and is kneaded and crushed, and the suspension weight is adjusted. It can be produced by other known methods such as a synthesis method, an emulsion polymerization method, an emulsion dispersion granulation method, and an encapsulation method. Among these production methods, the kneading / pulverization method is preferable from the viewpoint of production cost and production stability.

In producing a toner by a kneading and pulverizing method, a step of mixing the above-mentioned materials with a mixer such as a Henschel mixer, a step of melting and kneading the mixture, a step of cooling and kneading the kneaded material, A toner is produced by a step of finely pulverizing the coarsely pulverized particles and a step of classifying the obtained finely pulverized particles. Also, to improve the fluidity of the developer,
If desired, a fluidizing agent can be added to and mixed with the obtained toner. The toner contained in the developer of the present invention includes:
Volume average particle size of 4 to 12 μm, preferably 6 to 11 μm
Is preferably adjusted from the viewpoint of high definition reproducibility of the image.

Examples of the fluidizing agent include silica fine particles, titanium dioxide fine particles, amylna fine particles, magnesium fluoride fine particles, silicon carbide fine particles, boron carbide fine particles, titanium carbide fine particles, zirconium carbide fine particles, boron nitride fine particles, titanium nitride fine particles, zirconium nitride fine particles. Examples include fine particles, magnetite fine particles, molybdenum disulfide fine particles, aluminum stearate fine particles, magnesium stearate fine particles, and zinc stearate fine particles.

These fine particles are desirably subjected to a hydrophobic treatment with a silane coupling agent, a titanium coupling agent, a higher fatty acid, silicone oil, or the like before use. The amount of the fluidizing agent is 0.05 to 100 parts by weight of the toner.
It is desirable to use 5 parts by weight, preferably 0.1 to 3 parts by weight.

The developer of the present invention obtained as described above can be used in either a one-component developer using no carrier or a two-component developer used with a carrier. As the carrier used together with the toner of the present invention, a known carrier can be used, for example, a carrier composed of magnetic particles such as iron powder and ferrite, and a coated carrier in which the surface of the magnetic particles is coated with a coating material such as a resin. ,
Alternatively, any of a binder-type carrier obtained by dispersing a magnetic fine powder in a binder resin can be used. Such a carrier has a volume average particle size of 15 to 100.
μm, preferably 20 to 80 μm is suitable.

When a developer containing a positively chargeable toner is used, a preferred carrier is a carrier having a chargeability for the toner, that is, a resin having a negatively chargeable resin on the surface. Examples of such resins include polyester resins, polyolefin resins such as polyethylene, tetrafluoroethylene, vinylidene fluoride, homopolymers of fluorine-containing vinyl monomers or copolymers with other vinyl monomers. And the like. Particularly preferred is a coat-type carrier coated with the above-mentioned negatively-chargeable resin, or a binder-type carrier obtained by dispersing magnetic fine powder in the above-mentioned negatively-chargeable resin from the viewpoint of chargeability.

When the toner of the present invention is used as a negatively chargeable toner, a carrier having a positively chargeable resin on its surface is preferable. Examples of such a resin include an acrylic resin, a styrene-acrylic resin, and a silicone resin.
The following examples illustrate the invention in more detail.

[0061]

EXAMPLES In this example, "thermoplastic styrene-acrylic resin" refers to a styrene-butyl acrylate-butyl methacrylate-methacrylic acid copolymer (monomer weight ratio = 7:
(1.4: 1.4: 0.2, acid value 6.5 KOHmg / g)
And “polyester resin a” means polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl)
735 g of propane, polyoxyethylene (2,0)-
2,2-bis (4-hydroxyphenyl) propane 29
A product obtained by reacting 2.5 g, 448.2 g of terephthalic acid, and 22 g of trimellitic acid was referred to as “polyester resin b” and was referred to as polyoxypropylene (2,2) -2,2-bis (4
-Hydroxyphenyl) propane 735 g, polyoxyethylene (2,0) -2,2-bis (4-hydroxyphenyl) propane 292.5 g, terephthalic acid 249
g, 177 g of succinic acid, and 22 g of trimellitic acid.

(Synthesis of negative charge control resins A to C) 300 g of methanol, 100 g of toluene, 540 g of styrene,
-Acrylamide-2-methylpropanesulfonic acid (A
MPS) 60 g, lauroyl peroxide (initiator)
12 g was charged into a 2 liter flask, and solution polymerization was performed for 10 hours while stirring at 65 ° C. while introducing nitrogen. After drying this polymer under reduced pressure, it was pulverized using a jet mill to obtain a negatively-charged control resin A (particle size: 2 mm or less). This resin has a weight average molecular weight (Mw) of 5200 and an acid value of 30.1.
Met.

Also, negative control resins B and C were obtained in the same manner as in the synthesis of negative control resin A, except that the amounts of styrene, AMPS and initiator were changed as shown in Table 2. Weight average molecular weight (Mw) of these resins
Table 2 summarizes the acid value and the amount of raw materials used.

[0064]

[Table 2]

(Production of positive charge control agent masterbatch) In the following Examples and Comparative Examples, when a masterbatch type is used as the positive charge control agent, the binder resin used in the Examples or Comparative Examples is used. That is, a positive charge control agent masterbatch of a thermoplastic styrene-acrylic resin, a polyester resin a or a polyester resin b, and a quaternary ammonium salt compound was used. The manufacturing method is as follows. When a mixture of the polyester resins a and b was used as the toner binder resin, the mixed resin having the ratio was used as the master batch resin.

The masterbatch resin and the quaternary ammonium salt compound were charged into a pressure kneader at a weight ratio of about 7: 3 and kneaded at 120 ° C. for 1 hour. After cooling, the mixture was roughly pulverized with a hammer mill to obtain a positive charge control agent master batch having a positive charge control agent content of 30% by weight.

Example 1-93 parts by weight of thermoplastic styrene-acrylic resin-10 parts by weight of positive charge control agent (quaternary ammonium salt masterbatch)-Quaternary ammonium salt (P-53; manufactured by Orient Chemical Company)-Load control Resin A 0.5 parts by weight ・ Carbon black (Mogal L; manufactured by Cabot) 10 parts by weight ・ Polypropylene wax (softening point: about 145 ° C.) 4 parts by weight (Viscol 660P; manufactured by Sanyo Chemical Industries) ・ Magnetic powder (BR-605) 2 parts by weight

The above materials were mixed with a Henschel mixer (capacity 7
51), and mixed at 3000 rpm for 3 minutes. The mixture was mixed with a screw extrusion kneader (TEM) as shown in FIG.
50; manufactured by Toshiba Machine Co., Ltd.) at a temperature of 120 ° C. and a supply amount of 3
After continuous extrusion kneading under the conditions of 0 kg / hr and a screw rotation speed of 150 rpm, the mixture was rolled with a press roller (4) having a nip width of 1 mm, and further subjected to forced water cooling on a belt cooler (6).

This kneaded material was roughly pulverized with a feather mill (2 mm mesh). The coarsely pulverized material is finely pulverized by a mechanical pulverizer (Krypton KTM-O type; manufactured by Kawasaki Heavy Industries, Ltd.) to 11 μm, and a jet mill (IDS) equipped with a natural air flow classifier is used.
-2 type; manufactured by Nippon Pneumatic Co., Ltd.), and fine powder was cut by a rotary rotor classifier (50ATP classifier; manufactured by Hosokawa Micron) to obtain a toner having a volume average particle diameter of 11 μm. . Hydrophobic silica (R-974; manufactured by Nippon Aerosil Co., Ltd.) was added to the obtained toner.
15% by weight was added.

Examples 2 to 8 and Comparative Examples 1 to 7 Examples except that the binder resin, the positive charge control agent and the negative charge control resin shown in Table 3 or Table 4 were used in the amounts indicated in the table. In the same manner as in Example 1, a toner was obtained. The same amounts of carbon black, polypropylene wax and magnetic powder as in Example 1 were used.

The toners obtained in the above Examples and Comparative Examples were mixed with a carrier at a mixing weight ratio of 6:94 (toner: carrier), and the obtained developers were evaluated for the following evaluation items. Note that carriers a to c described later were used.

(1) Charge Amount For a developer using a positively chargeable toner, a copying machine EP
4050 (manufactured by Minolta), a developer using a negatively chargeable toner is copied using a copying machine Di-30 (manufactured by Minolta), and after copying 100,000 sheets, the developer is sampled and weighed with a precision balance. The developer 1g thus placed is uniformly placed on the entire surface of the conductive sleeve (41) of the charging device shown in FIG. 2, and the number of rotations of the magnet roll (42) provided in the conductive sleeve (41) is adjusted. 100r
pm.

Then, a bias voltage of 3 KV is applied from a bias power supply (43) with the same polarity as the charged potential of the toner.
The conductive sleeve (41) is rotated for 30 seconds, and the potential Vm at the cylindrical electrode (44) at the time when the conductive sleeve (41) is stopped is read. The weight of the toner attached to (44) was weighed with a precision balance, and the average charge amount (μC / g) of each toner was determined.

(2) Image density (ID) For a developer using a positively chargeable toner, a copying machine EP
4050 (manufactured by Minolta), a developer using a negatively chargeable toner is copied using a copying machine Di-30 (manufactured by Minolta) to copy 100,000 sheets, and the toner is fixed on copy paper. Image density of Macbeth reflection densitometer (RD
920; manufactured by Macbeth Co.) and evaluated according to the following ranking. ◎: ID 1.4 or more; ：: ID 1.2 or more and less than 1.4; Δ: ID 1.0 or more and less than 1.2;

(3) Background fog Similar to the image density evaluation, except that white paper was used for the image to be copied, after copying 100,000 sheets, toner fog in the copied image was observed and rank was determined as follows. Attached. ：: Fog was hardly observed; Δ: Fog was slightly observed, but there was no problem in practical use; ×: Toner fog was large.

The above evaluation results are shown in Tables 3 and 4 below together with the type of carrier used and the types and amounts of the binder resin, the positive charge control agent and the negative charge control resin used in the production of the toner.

[0077]

[Table 3]

[0078]

[Table 4]

In Tables 3 and 4, 1) “S
"t-Ac" is a thermoplastic styrene-acrylic resin;
“ES-a” indicates a polyester resin a, and “PES-b” indicates a polyester resin b. 2) “Addition amount at the time of the masterbatch” means a converted value of the amount of the binder resin contained in the masterbatch when the positive charge control agent is of a masterbatch type. 3) In the species of the positive charge control agent, "quaternary ammonium salt M" indicates a quaternary ammonium salt masterbatch, and the others indicate that the positive charge control agent was used as it was. 4) The "addition amount" of the positive charge control agent is
When the positive charge control agent is of a master batch type, it means a converted value of the amount of the positive charge control agent contained in the master batch.

Here, the acid value was measured according to the following. A precisely weighed sample was dissolved in a neutralized xylene / n-butanol mixed solvent, and titrated with a previously standardized 0.1N-potassium hydroxide alcohol solution, and the neutralization amount was calculated by the following equation.

[0081]

(Equation 1) (F is a factor of an alcohol solution of 0.1 N potassium hydroxide)

(Production of Carrier a) A binder type carrier was produced as a carrier a as follows. Component Weight parts ・ Polyester resin (manufactured by Kao; NE-1110) 100 ・ Inorganic magnetic powder (manufactured by TDK; MFP-2) 500 ・ Carbon black (manufactured by Mitsubishi Kasei; MA # 8) 2

The above-mentioned materials were sufficiently mixed and pulverized by a Henschel mixer, and then melt-kneaded using an extruder kneader set at a cylinder portion of 180 ° C. and a cylinder head portion of 170 ° C. The kneaded material was cooled, coarsely pulverized, finely pulverized with a jet mill, and further classified using an air classifier to obtain a carrier a having a volume average particle size of 55 μm.

(Production of Carrier b) A coated carrier (polyester resin-coated type) was produced as the carrier b. First, a coating resin was manufactured.・ Polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane 350 g ・ Polyoxyethylene (2,2) -2,2-bis (4-hydroxyphenyl) propane 330 g ・ Isophthalic acid 400 g・ Dibutyltin oxide 2g

The above composition was placed in a 3 liter glass four-necked flask, fitted with a thermometer, a stainless steel stirring rod, a falling condenser, and a nitrogen inlet tube, and heated at 200 ° C. in a mantle heater under a nitrogen stream. The mixture was reacted with stirring to obtain a polyester resin of 15 KOH mg / g.

The polyester resin was diluted with toluene to prepare a polyester resin solution having a solid content of 2% by weight. A fired ferrite powder (F-300; average particle size: 50 μm, bulk density: 2.53 g / cm; manufactured by Powder Tech) was used as a core material, and the amount of resin coated on the core material was about 1% by weight of the polyester resin solution. Was applied with a spiral coater (manufactured by Okada Seiko Co., Ltd.) and dried. The obtained carrier is heated at 170 ° C. for 2
It was left for a time and fired. After cooling, ferrite powder bulk
It was crushed using a screen shaker equipped with a screen mesh having a spread of 210 μm and 90 μm to obtain a resin-coated ferrite powder. This ferrite powder was subjected to the above-mentioned coating and firing and crushing three more times to obtain a volume average particle size of 5
3 μm carrier b was obtained.

(Production of Carrier c) A coated carrier was produced as the carrier c. A 500-ml flask equipped with a stirrer, a condenser, a thermometer, a nitrogen inlet tube, and a dropping device was charged with 100 parts by weight of methyl ethyl ketone. 36. Methyl methacrylate at 80 ° C. under a nitrogen atmosphere
7 parts by weight, 2-hydroxyethyl methacrylate 5.1
Parts by weight, 58.2 parts by weight of 3-methacryloxypropyltris (trimethylsiloxy) silane and 1,1′-
A solution obtained by dissolving 1 part by weight of azobis (cyclohexane-1-carbonitrile) in 100 parts by weight of methyl ethyl ketone was dropped into the reactor over 2 hours and aged for 5 hours.

To the obtained resin, isophorone diisocyanate / trimethylolpropane adduct (IPDI / TMP system: NCO% = 6.1%) was added as a crosslinking agent to O.
After adjusting the H / NCO molar ratio to be 1/1, it was diluted with methyl ethyl ketone to prepare a coating resin solution having a fixed ratio of 3% by weight.

Fired ferrite powder F-300 as core material
(Volume average particle size: 50 μm, manufactured by Powder Tech Co.), and the above coating resin solution was applied and dried by a spira coater (manufactured by Okada Seiko Co., Ltd.) so that the coating resin amount to the core material was 1.5% by weight. .

The obtained carrier was calcined in a hot air circulating oven at 160 ° C. for 1 hour. After cooling, the ferrite powder bulk was crushed using a sieve shaker equipped with a 106 μm and 75 μm screen mesh to obtain Carrier c.

[0091]

The developer of the present invention is excellent in developability such as image density and the like over a long printing run, has less fogging, and is excellent in safety. In particular, the developer of the present invention hardly causes a decrease in chargeability.

[Brief description of the drawings]

FIG. 1 shows a schematic configuration diagram of a kneader provided with a press roller.

FIG. 2 shows a schematic configuration diagram of a test charging measurement device.

[Explanation of symbols]

1: toner mixture, 2: heating jacket, 3: kneading zone, 4: press roller, 5: belt-shaped molded product, 6: conveyor, 41: conductive sleeve, 42: magnet roll,
43: Pierce power supply, 44: cylindrical electrode

Claims (5)

[Claims] 1. An electrostatic image developer comprising at least a binder resin, a colorant, and a toner comprising at least two types of charge control materials, wherein the charge control material comprises a positive charge control agent and a negative charge control resin. The total content of the positive charge control agent and the negative charge control resin is
2 to 10 parts by weight with respect to 00 parts by weight, and the content ratio by weight of the positive charge control agent and the negative charge control resin is 100: 1 to 1
3: 1, and the acid value (KOHmg /
a product of g) and a content (parts by weight) with respect to 100 parts by weight of the binder resin of 1 to 50, a developer for an electrostatic image containing a positively chargeable toner. 2. An electrostatic image developer comprising at least a binder resin, a colorant, and a toner comprising two or more types of charge control materials, wherein the charge control material is formed from a positive charge control agent and a negative charge control resin. The total content of the positive charge control agent and the negative charge control resin is
2 to 10 parts by weight with respect to 00 parts by weight, and the weight ratio of the positive charge control agent and the negative charge control resin is 1: 100 to 100 parts by weight.
1: 3, the acid value (KOHmg /
a product of g) and the content (parts by weight) with respect to 100 parts by weight of the binder resin of 35 to 280, wherein the developer for an electrostatic image contains a negatively chargeable toner. 3. The method according to claim 1, wherein the negative charge control resin comprises 2-acrylamido-2-methylpropanesulfonic acid, styrene and / or
3. The electrostatic image developer according to claim 1, which is a copolymer containing α-methylstyrene as a main component. 4. The developer for an electrostatic image according to claim 1, wherein a master batch of a positive charge control agent and a styrene resin or a polyester resin is used as the positive charge control agent. . 5. The electrostatic image developer according to claim 1, wherein the positive charge control agent is a quaternary ammonium salt.