JP2001305777A - Developer for electrostatic charge image development - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developer for development of an electrostatic charge image showing stable electrification behavior during printing and causing little splashing of the toner and no contamination in a device and making the maintenance easy. SOLUTION: In the developer for development of an electrostatic charge image consists of a magnetic carrier and color resin particles containing at least a binder resin and a coloring agent, the proportion of color resin particles having >=12 μm and <16 μm particle size in the developer and the specific charge amount of the above color resin particles satisfy inequality (1): 5.18+0.12×A<B, wherein A is the proportion (vol.%) of color resin particles having >=12 μm and <16 μm particle size and B is the specific charge amount Q/M (μC/g) of the color resin particles having >=12 μm and <16 μm particle size.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic image developer used in an electrophotographic method, an electrostatic recording method, or an electrostatic printing method.

[0002]

2. Description of the Related Art As an electrophotographic method, US Pat.
No. 97,691, JP-B-42-23910 or JP-B-43-24748, various methods are described. Usually, various methods are described on an electrostatic latent image carrier such as a photoconductive photoreceptor. An electrostatic latent image is formed by charging and exposure, and then the electrostatic latent image is developed with a toner composition containing a colorant in a binder resin, and the obtained toner image is transferred to a support such as transfer paper. In general, a visible image is formed by fixing.

[0003] Further, many methods are known as a developing method in electrophotography, but when roughly classified, fine particles (20 to 500) such as iron powder, ferrite, nickel, and glass are used.
μm) as a developer, and a one-component development method using a developer consisting of only the toner.

Representative examples of the two-component developing method include a cascade method described in US Pat. No. 2,618,552 and a magnetic brush method described in US Pat. No. 2,874,063. In these methods, the carrier shares functions such as agitating, transporting, and charging the developer, and the function separation between the carrier and the toner is clear. For this reason, it is widely used at present because charge control of the toner and formation of the developer layer are relatively easy, and high-speed operation is possible.

[0005] With the development of the information society in recent years, in each field of electrophotography, electrostatic recording, and electrostatic printing, high quality of printed images, high speed of recording, high density, and long-term storage stability have been achieved. Demands for improvement of toner characteristics for recording an electrostatic latent image on a non-printing medium have been greatly increased.

An apparatus using the electrostatic image developing method includes a copying machine or a printer. The processing speed varies depending on the manufacturer and type. 30
Many machines have a processing speed of about sheets per minute, or about 60 to 100 sheets per minute for office copying machines. In particular, due to the recent increase in the speed of the developing device, a high-speed machine which has a processing speed of 100 sheets / minute in A4 paper lengthwise conversion, 140 sheets / minute in A4 paper width conversion, and a developing speed of 30 m / min. It is shifting to.

[0007] In such a toner for a two-component developer suitable for high-speed printing, a stable charging behavior in multi-copy printing and a stable image with little fog obtained as a result, and the inside of the machine can be used for a long period of use. Elimination of scattered toner that does not contaminate is an important issue, and these issues are very much dependent on the charging characteristics of the toner.

In particular, regarding the contamination inside the apparatus, in the case of a high-speed printing apparatus, the problem of toner scattering is great, and not only contamination of the printed image but also contamination of the inside of the apparatus impairs the maintainability and further causes the trouble of the apparatus. This is a big problem that can happen.

On the other hand, recently, polyester resins have been used as resins from the viewpoint of improving high durability.
Polyester resin is styrene
Compared with an acrylic resin, it has a strong negative chargeability, and is not suitable for producing a positively chargeable toner particularly used for high-speed printing. For this reason, it is a fact that none of the above-mentioned objects required for the high-speed printing toner, such as toner scattering, is satisfied.

[0010]

SUMMARY OF THE INVENTION The present invention provides an electrostatic charge image which shows a stable charging behavior during printing even when a polyester resin is used, and does not stain the inside of the apparatus due to a small amount of scattered toner, and is easy to maintain. An object of the present invention is to provide a developer for development. In particular, it is an object of the present invention to provide a developer for developing an electrostatic image capable of solving the above-mentioned problem even at the time of high-speed printing at a speed exceeding 20 m / min, or even at a speed exceeding 30 m / min.

[0011]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems. As a result, among the developers used for development, relatively large particles of 12 μm or more and less than 16 μm in the toner particles are used. The inventors have found that the ratio (volume%) of the toner belonging to the diameter range and the specific charge amount greatly affect the toner scattering amount, and have reached the present invention.

That is, the present invention relates to a developer for developing an electrostatic image, comprising colored resin particles containing at least a binder resin and a colorant, and a magnetic carrier, the developer having a particle size of 12 μm or more and less than 16 μm. The ratio of the colored resin particles and the specific charge amount of the colored resin particles are determined by the following formula: 5.18 + 0.12 × A <B --- (1) (where A is 12 μm or more in the colored resin particles) 16μ
m, and B is the specific charge amount Q / M of the colored resin particles having a particle diameter of 12 μm or more and less than 16 μm (μC /
g). The present invention provides a developer for developing an electrostatic image, characterized by satisfying the following.

Generally, a toner is colored resin particles containing a binder resin, a colorant, a release agent, and a charge controlling agent. The toner scatters when the specific charge of the toner decreases, the toner and the carrier Is a phenomenon in which the Coulomb force cannot overcome the centrifugal force due to the rotation of the magnetic brush, and the toner flies out of the carrier.However, the process speed during development, the charge amount of the toner, and the like are intricately entangled.
It was a qualitative discussion.

The particle size of the toner supplied to the product is about 1
Although produced with a target particle size of 0 μm, it is generally obtained as a powder having a certain particle size distribution, depending on the method of pulverization and classification.

When the powder as an aggregate having such various particle diameters was intensively examined, it was found that the ratio of the toner having a particle size of 12 μm or more and less than 16 μm and the specific charge thereof had the relationship of the above formula (1). Thus, it has been found that this is very effective in suppressing the amount of toner scattering. The left side of the above equation (1) indicates the degree of scattering by centrifugal force having a particle diameter of 12 μm or more and less than 16 μm, and the right side indicates the degree of suppressing scattering by the Coulomb force of the particle diameter.

In particular, the electrostatic image developer containing the colored resin particles (toner) that satisfies the above formula (1) is a developing device that performs high-speed printing at a speed exceeding 20 m / min, and more preferably at a speed exceeding 30 m / min. Can be used effectively as a developer for

Usually, the particle size distribution of the powder can be easily measured by a multisizer (a particle size distribution measuring device manufactured by Coulter), and the charge amount distribution according to the particle size of the toner is E-
It can be easily measured with a spurt analyzer (manufactured by Hosokawa Micron). According to the present invention, by directly using a value obtained by such a simple measurement, it is possible to easily design the toner to suppress the amount of scattering.

The E-Spurt analyzer vibrates the toner particles by dropping the toner particles between two electrodes having opposite acoustic vibration polarities, and moves the toner particles to the electrodes by the electric field action of the electrodes. At this time, the particle frequency and the charge amount of each particle are calculated by simultaneously measuring the frequency and the moving distance of the toner by the laser Doppler method. According to the present apparatus, it is possible to measure the charge amount distribution of the particles in a specific particle diameter range and easily measure the total charge of the particles. E
-For details of the principle of measuring the amount of toner charge by a spurt analyzer, see "Japan Hardcopy '
90 papers, pages 101-104, by Hosokawa Micron Corporation.

The developer for developing an electrostatic image according to the present invention can be obtained by mixing and charging a toner and a magnetic carrier so as to satisfy the above formula (1).

In the present invention, colored resin particles containing at least a binder resin and a colorant are used. The binder resin used in the present invention can be used without particular limitation as long as it satisfies the above formula (1) when converted to toner. Specifically, polyester resin, polystyrene resin, styrene acrylic resin, styrene butadiene resin, epoxy resin,
Butyral resin, xylene resin, coumarone indene resin and the like can be mentioned. Among them, styrene acrylic resin and polyester resin are preferable, and polyester resin is particularly preferably used because of good balance between fixability and durability. be able to.

The polyester resin that can be used in the present invention is not particularly limited in molecular structure or composition, and for example, a resin obtained by dehydrating and condensing a dicarboxylic acid and a diol described below by a conventional method can be used. .

(1) Dicarboxylic acids Examples of dicarboxylic acids include phthalic anhydride, terephthalic acid, isophthalic acid, orthophthalic acid, adipic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, citraconic acid, and hexahydrophthalic anhydride. And dihydrocarboxylic acids such as tetrahydrophthalic anhydride, cyclohexanedicarboxylic acid, succinic acid, malonic acid, glutaric acid, azelaic acid, and sebacic acid, and derivatives or esterified products thereof.

(2) Diols The diols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, butanediol, pentanediol, hexanediol, cyclohexanedimethanol, bisphenol A, Polyoxyethylene- (2.0) -2,2-
Bis (4-hydroxyphenyl) propane and its derivatives, polyoxypropylene- (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene- (2.2) -polyoxyethylene- ( 2.0)
-2,2-bis (4-hydroxyphenyl) propane,
Polyoxypropylene- (6) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene-
(2.2) -2,2-bis (4-hydroxyphenyl)
Propane, polyoxypropylene- (2.4) -2,2
-Bis (4-hydroxyphenyl) propane, polyoxypropylene- (3.3) -2,2-bis (4-hydroxyphenyl) propane and its derivatives, polyethylene glycol, polypropylene glycol, ethylene oxide-propylene oxide random copolymer Coalescent diol, ethylene oxide-propylene oxide block copolymer diol, ethylene oxide-tetrahydrofuran copolymer diol, polycaprolactone diol, and the like.

(3) Trivalent or higher polyvalent monomer In addition to the above dicarboxylic acids and diols, trifunctional or higher polyfunctional monomers such as trimellitic acid, trimellitic anhydride, pyromellitic acid, and pyromellitic anhydride can be used. A polyvalent carboxylic acid or a derivative or esterified product thereof, or
Sorbitol, 1,2,3,6-hexanetetraol, 1,4-sorbitan, pentaerythritol, 1,
2,4-butanetriol, 1,2,5-pentanetriol, glycerin, 2-methylpropanetriol,
2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-
Trimethylolbenzene, trifunctional or higher polyhydric alcohol, or cresol novolak type epoxy resin, phenol novolak type epoxy resin, polymer or copolymer of vinyl compound having epoxy group, epoxidized resorcinol-acetone condensation Products, partially epoxidized polybutadiene or other pentavalent epoxy compound,
Further, divalent to tetravalent bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, trimethylolethane triglycidyl ether, pentaerythritol tetraglycidyl ether, etc. Epoxy compounds and the like can be used as needed.

The polyester resin in the present invention can be obtained by performing a dehydration condensation reaction or a transesterification reaction using the above-mentioned raw material components in the presence of a catalyst.
The reaction temperature and reaction time at this time are not particularly limited, but are usually 150 to 300 ° C. and 2 to 24 hours.

As a catalyst for carrying out the above reaction, for example, zinc oxide, stannous oxide, tetrabutyl titanate, monobutyltin oxide, dibutyltin oxide, dibutyltin dilaurate, p-toluenesulfonic acid and the like can be appropriately used. .

The polyester resin has a glass transition temperature of 55 ° C. to 85 ° C. and a softening point of 90 ° C. to 1 ° C.
Polyester resins at 80 ° C. are preferred. Further, the temperature is particularly preferably 100 to 170 ° C. The softening point in the present invention is a softening point measured by a method according to ASTM E28-517. Further, the acid value is preferably 20 mgKOH / g or less, particularly preferably 10 mgKOH / g or less from the viewpoint of storage stability and developability without causing a decrease in the charge amount due to an increase in hygroscopicity. preferable.

Further, it is preferable to use a resin obtained by combining a linear polyester resin (i) and a crosslinked polyester resin (ii) as described below, in order to secure a wider fixing / offset region. When such a combination is performed, each resin does not need to have the above-mentioned glass transition temperature or softening point, but may be prepared so that the combined resin has the above-mentioned glass transition temperature or softening point.

The crosslinked polyester resin (ii) is
THF-insoluble matter may be present in the structure. The THF-insoluble matter referred to in the present invention refers to the residue on the filter paper after 1 g of the synthesized resin powder is put on a special filter paper (No. 86R manufactured by Toyo Roshi Kabushiki Kaisha) and refluxed for 8 hours in a Soxhlet type reflux apparatus using THF as a solvent. . The term “crosslinking” as used in the present invention includes both a branched structure in which the polyester main chain is branched and a structure in which the polyester main chain is connected in a network. In general, a polyester having a branched structure has TH as defined in the present invention.
The content of the F-insoluble component is 0%, and the content of the THF-insoluble component increases as the network structure increases.

The linear polyester resin (i) more preferably used in the present invention does not contain a THF-insoluble component,
It is a polyester resin having a softening point of 80 ° C. to 120 ° C. and a glass transition point of 55 ° C. to 85 ° C. Such a polyester resin is obtained by, for example, dehydration condensation of a dicarboxylic acid and a diol by a usual method. Can be obtained.

The polyester resin used in the present invention only needs to have a glass transition point and a melt viscosity characteristic suitable for a two-component developing toner.

As the linear polyester resin (i),
The softening point is preferably in the range of 80 ° C to 120 ° C, and more preferably in the range of 90 ° C to 110 ° C. As the molecular weight, a weight average molecular weight (Mw) is preferably 7000 to 12000, and a ratio Mw / Mn of the weight average molecular weight to the number average molecular weight (Mn) is 4 or less, and especially 3
The following is preferred.

The softening point is less than 80 ° C. or Mw is 7
If it is less than 000, the toner is liable to cause an aggregation phenomenon,
Easy to cause troubles during storage and printing, with a softening point of 1
When the temperature exceeds 20 ° C. or when Mw exceeds 12,000, the fixing property often deteriorates.

The crosslinked polyester resin (ii) that can be used in the present invention is obtained by dehydrating and condensing the above-mentioned dicarboxylic acids (1) and diols (2), and also a trivalent or higher polyvalent monomer (3). Can be obtained by

As the crosslinked polyester resin (ii),
Preferably, the softening point is in the range of 130 ° C to 180 ° C, and more preferably, in the range of 140 ° C to 170 ° C. Further, the content of the THF-insoluble component is more than 0 and not more than 20%, and the Mw of the THF-soluble component is from 100,000 to
400,000, Mw / Mn is preferably 10 or more, particularly preferably 15 or more.

When the softening point is less than 130 ° C. or Mw is 100,000 or less, the toner tends to cause an offset phenomenon at the time of fixing. When the softening point exceeds 180 ° C., the THF insoluble content is 20% or more and Mw is If it exceeds 400,000, the fixability often deteriorates.

The mixing ratio of the linear polyester resin (i) and the crosslinked polyester resin (ii) is such that the weight ratio (i) /
(Ii) = 2/8 to 8/2, preferably 3 /
More preferably, it is 7 to 7/3. When the mixing ratio of the linear polyester resin is within this range, both excellent fixing properties and excellent offset resistance can be achieved.

On the other hand, both the linear polyester and the crosslinked polyester preferably have a glass transition temperature (Tg) of 45 ° C. or higher, and particularly preferably have a Tg of 50 ° C. to 85 ° C.

Further, the acid value is from 1 to 20 mg KO.
H / g is preferred, and particularly preferably 3 to 10 mgKOH / g. If the acid value is too high, the hygroscopicity may increase and the charge amount may decrease, which is not preferable from the viewpoint of storage stability and developability.

The colorant used in the present invention is not particularly limited as long as it satisfies the above formula (1), and includes conventionally known colorants. Specifically, carbon blacks such as furnace black, channel black, acetylene black, thermal black, lamp black and the like classified according to the production method are used as black colorants, and phthalocyanine C.I. I.
Pigment Blue 15-3, indanthrone C.I. I. Pigment Blue 60 and the like are quinacridone-based C.I. I. Pigmen
t Red 122, an azo C.I. I. Pigment
Red 22, C.I. I. PigmentRed 48:
1, C.I. I. Pigment Red 48: 3, C.I.
I. Pigment Red 57: 1, etc., and an azo-based C.I. I. Pigment Yellow
ow 12, C.I. I. Pigment Yellow 1
3, C.I. I. Pigment Yellow 14, C.I.
I. Pigment Yellow 17, C.I. I. Pi
gment Yellow 97, C.I. I. Pigmen
t Yellow 155, isoindolinone-based C.I.
I. Pigment Yellow 110, a benzimidazolone C.I. I. Pigment Yellow 1
51, C.I. I. Pigment Yellow 154,
C. I. Pigment Yellow 180, and the like. The colorant content is in the range from 1 part by weight to 20 parts by weight. These colorants can be used alone or in combination of two or more.

In the present invention, a release agent can be used.

As the release agent used for the toner of the present invention, any known and commonly used release agents can be used, for example, synthetic waxes such as polyolefin waxes such as polyethylene wax and polypropylene wax, carnauba wax, montan ester and the like. Natural waxes such as waxes and / or rice waxes.

The above waxes may be used alone or in combination.
A good fixing offset performance can be obtained by adding from 1 to 15 parts by weight, preferably from 1 to 5 parts by weight. When the amount is less than 0.3 part by weight, the offset resistance tends to be insufficient, and when the amount is more than 15 parts by weight, the fluidity of the toner is reduced, and the toner easily adheres to the carrier surface, so that a spent carrier is easily generated. In many cases, the charging characteristics of the toner are adversely affected.

In the present invention, a charge control agent, in particular, a positively chargeable charge control agent can be used.

The positively chargeable charge control agent used in the present invention is not particularly limited as long as it satisfies the above formula (1), and a conventionally known and commonly used positively chargeable charge control agent can be used. For example, a nigrosine dye, a quaternary ammonium salt, a resin containing a quaternary ammonium salt, and / or a resin containing an amino group can be used alone or in combination of two or more.

The content of the charge control agent is 10
It is preferably used in an amount of 0.3 to 10 parts by weight, more preferably 1 to 5 parts by weight, per 0 parts by weight.

The quaternary ammonium salt compound is particularly preferably at least one selected from general formulas (I) and (2) having the following structure. The compound having the structure of (1) includes Bontron P-51;
TP-302, TP-415, TP
-610; (made by Hodogaya Chemical).

It is also preferable to use a compound represented by the following general formula (3).

General formula (1)

[0050]

Embedded image [Wherein, R _{1 to} R ₃ represent a CnH2n + 1 group. Where n
Represents an integer of 1 to 10. Further, R _{1 to} R ₃ may be the same or different. ]

General formula (2)

[0052]

Embedded image Wherein R ₁ , R ₂ , R ₃ and R ₄ are each independently a hydrogen atom, an alkyl or alkenyl group having 1 to 22 carbon atoms, an unsubstituted or substituted aromatic group having 1 to 20 carbon atoms, Represents an aralkyl group having 7 to 20 carbon atoms, A ^- is a molybdate anion or a tungstate anion,
Represents a heteropolyacid anion containing molybdenum or tungsten atoms. ]

General formula (3)

[0054]

Embedded image Wherein m represents 1, 2 or 3, and n represents 0, 1
Or 2, and M is a hydrogen atom or a monovalent metal ion. X and Z each represent 1 or 2, and Y represents 0 or 1. Further, when X = 1, Y = 1 and Z = 1, and when X = 2, Y = 0 and Z = 2. R _{5 to} R ₁₂ are hydrogen, a linear or branched saturated or unsaturated alkyl group having 1 to 30 carbon atoms, an alkoxylene group having 1 to 4 carbon atoms, or a general formula (-C 2-5 alkylene-O ) N-R
(Where R is hydrogen or an alkyl group or acyl group having 1 to 4 carbon atoms, and n is an integer of 1 to 10), wherein R ₁ , R ₂ ,
R ₃ and R ₄ are hydrogen, a linear or branched saturated or unsaturated alkyl group having 1 to 30 carbon atoms, or a general formula (—CH ₂ —CH ₂ —O) n—R (however, R is hydrogen or an alkyl group or an acyl group having 1 to 4 carbon atoms, and n is an integer of 1 to 10), an oxyethyl group represented by the formula: and a mononuclear or polynuclear alicyclic group having 5 to 12 carbon atoms. Residue, mononuclear or polynuclear aromatic residue or araliphatic residue. ]

More specifically, there are the following compounds.

Compound (1-1)

[0057]

Embedded image

Compound (2-1)

[0059]

Embedded image

Compound (2-2)

[0061]

Embedded image

Compound (2-3)

[0063]

Embedded image

Compound (2-4)

[0065]

Embedded image

Compound (2-5)

[0067]

Embedded image

Compound (2-6)

[0069]

Embedded image

Compound (2-7)

[0071]

Embedded image

Compound (2-8)

[0073]

Embedded image

Compound (2-9)

[0075]

Embedded image

Compound (2-10)

[0077]

Embedded image

Compound (2-11)

[0079]

Embedded image

Compound (3-1)

[0081]

Embedded image

Compound (3-2)

[0083]

Embedded image

In the present invention, a nigrosine dye and a quaternary ammonium salt compound are preferably used in combination as a charge controlling agent.

The weight ratio of the nigrosine dye to the quaternary ammonium salt compound is not particularly limited, but is 1/9 to 9
/ 1, more preferably 2/8 to 8/2. Nigrosine dyes have a high positive charge imparting ability, but the uniformity and stability of charging tend to be insufficient.
When used alone, fogging is likely to occur, resulting in a printed image with insufficient sharpness. Although the quaternary ammonium salt compound has insufficient positive charge-imparting ability and is devised to be used alone, the use of these quaternary ammonium salt compounds and a nigrosine dye results in a synergistic effect,
Uniformity and stability of electrification can be obtained, which effectively and advantageously acts on toner scattering, and a clear print image free of fog during continuous printing can be easily and stably obtained.

If the weight ratio of the nigrosine dye is less than 1, it is difficult to obtain sufficient charge on the toner, it is difficult to perform normal development, and the transfer efficiency to paper tends to decrease. As a result, there is a tendency that a low-quality image is obtained in which solid toner adheres non-uniformly and the outline of an image is unclear. Further, due to the low charge, the developer often becomes a short-lived developer in which toner scatters sharply. On the other hand, when the weight ratio used is more than 9, the charge amount becomes too high, and in many cases, the developer exhibits a low density and low image quality and unstable charging behavior in continuous printing.

As described above, when the selection is made within the above-mentioned range, a desired charge amount can be easily obtained, and as a result, printing with high density and high image quality can be obtained, and a developer with very little toner scattering can be obtained.
By optimally adjusting the ratio of the two, an optimal charge amount can be obtained, and a long-life developer with no toner scattering that can be printed with high density and high quality without fogging and with clear image outlines. Obtainable.

The colored resin particles in the present invention function as a toner, and are composed of the binder resin composed of the polyester resin as described above and a coloring agent. The colored resin particles contain other additives. May be.

As an example, a lubricant such as metal soap and zinc stearate can be used, and as an abrasive, for example, cerium oxide and silicon carbide can be used.

The toner of the present invention can be obtained by an extremely general manufacturing method regardless of a specific manufacturing method.
In the present invention, a resin, a colorant, a release agent, and a charge controlling agent are well mixed in a non-molten state in advance using a mixing stirrer such as a Henschel mixer, and then melt-kneaded at a temperature equal to or higher than the melting point (softening point) of the resin. By doing so, it can be suitably implemented.

In preparing the toner of the present invention, among various positive charge control agents, various carbon blacks and the like which are hardly dispersed in a resin, for example,
A pre-mixing of the positive charge control agent and / or carbon black etc. in a non-molten state in advance, followed by a two-stage pre-mixing in which a release agent is further mixed in a non-molten state, and then melt-kneading the mixture. Is preferred. That is, it is optimal to melt-knead after multi-stage premixing.

Further, the above-mentioned mixed product is pulverized and classified to obtain the toner of the present invention.

[0093] Specifically, for example, a dry mixture obtained by pre-mixing multiple stages as necessary and containing the above-mentioned resin, colorant, release agent, and charge control agent as essential components is, for example, a two-roll mill. Mixing is performed by a kneading means such as a three-roll, pressure kneader, or a twin-screw extruder. At this time, the colorant or the like may be uniformly dispersed in the resin, and the conditions for the melt-kneading are not particularly limited, but are usually from 80 ° C. to 180 ° C. for 30 seconds to 2 hours. The coloring agent may be previously subjected to a flushing treatment so as to be uniformly dispersed in the resin, or a master batch melt-kneaded with the resin at a high concentration.

Then, after cooling, it is finely pulverized by a mechanical pulverizer such as a turbo mill or a kryptron, or an air pulverizer such as a spiral jet mill, a counter jet mill, or an impinging plate jet mill, and is then pulverized by an air classifier or the like. There is a method of classifying.

The volume average particle diameter of the particles constituting the toner matrix is not particularly limited, but is usually adjusted to be 5 to 15 μm.

The toner may satisfy the above formula (1) only with the colored resin particles (the parent toner), but the toner using both the colored resin particles and the external additive is easier. In addition, the above equation (1) is likely to be satisfied.

Usually, an external additive is mixed with the thus obtained toner base using a mixer such as a Henschel mixer.

The external additives are used for modifying the surface of the toner base such as improving the fluidity and charging characteristics of the toner, and include inorganic fine powders such as silicon dioxide (silica), titanium oxide and alumina. And surface-treated with a hydrophobizing agent such as silicone oil, resin fine powder, or the like. As the external additive, silica is preferable because it is easy to satisfy the above formula.

Examples of silica include those having hydrophobicity and the like among silicon dioxides, and examples thereof include those obtained by subjecting silicon dioxide to a surface treatment with various polyorganosiloxanes, silane coupling agents, or the like. For example, there is one that is commercially available under the following trade names.

AEROSIL: R972, R974, R
202, R805, R812, RX200, RA200
HS, RY200, R809, RX50 (Nippon Aerosil Co., Ltd.) PACKER: HDK H2000, H2050EP,
HDK H3050EP, HVK2150 (Wacker Chemicals East Asia K.K.) Nipsil: SS-10, SS-15, SS-20,
SS-50, SS-60, SS-100, SS-50
B, SS-50F, SS-10F, SS-40, SS-
70, SS-72F (Nippon Silica Industry Co., Ltd.)

These silicas have different average particle sizes.
More than one species may be used in combination. The use ratio of silica is usually 0.05 to 5% by weight, preferably 0.1 to 3% by weight, based on the toner base.

The developer for developing an electrostatic image of the present invention comprises the toner of the present invention containing the above colored resin particles, and a magnetic carrier, preferably a magnetic carrier having a surface coated with a resin.

As the core agent (magnetic carrier) of the carrier used in the present invention, iron powder, magnetite, ferrite and the like used in a general two-component developing system can be used. Among them, the true specific gravity is low, the resistance is high, and the environment is low. Ferrite or magnetite, which has excellent stability and is easy to form into a sphere and has good fluidity, are preferably used. The shape of the core agent can be used without any particular problem, such as spherical or amorphous. The average particle size is generally 10 to 500 μm, but is preferably 30 to 100 μm for printing a high-resolution image.

Examples of the coating resin for covering these core agents include polyethylene, polypropylene, polystyrene, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether polyvinyl ketone, and vinyl chloride. / Vinyl acetate copolymer, styrene / acrylic copolymer, straight silicone resin comprising organosiloxane bond or its modified product, fluororesin, (meth) acrylic resin, polyester, polyurethane, polycarbonate, phenolic resin, amino resin, melamine resin , Benzoguanamine resin, urea resin, amide resin, epoxy resin and the like can be used.

Among these, silicone resin, fluorine resin, and (meth) acrylic resin are particularly excellent in charge stability and coating strength, and can be more preferably used. That is, the resin-coated carrier used in the present invention is a ferrite as a core agent,
Alternatively, a resin-coated magnetic carrier coated with at least one resin selected from silicone resin, fluororesin, and (meth) acrylic resin using magnetite is preferable.

The method of coating the surface of the carrier core material with the resin is not particularly limited, but a dipping method of dipping in a solution of the coating resin, a spray method of spraying the coating resin solution onto the surface of the carrier core material, or a carrier method. Fluidized bed method in which the carrier is sprayed while being floated by flowing air, a kneader coater method in which a carrier core material and a coating resin solution are mixed in a kneader coater, and a solvent is removed.

The solvent used in the coating resin solution is not particularly limited as long as it dissolves the coating resin. For example, toluene, xylene, acetone, methyl ethyl ketone, tetrahydrofuran, dioxane and the like can be used. The thickness of the coating layer on the carrier surface is usually 0.1
〜3.0 μm.

The carrier preferably used in the present invention, which is coated with a resin, is subjected to a heat treatment as required. In particular, when coated with a resin containing a cross-linking component, the film is reinforced by a heat cross-linking reaction, so that a more durable carrier is preferable.

When the heat treatment is performed, the charge amount when mixed with the toner can be controlled by the temperature condition. Generally, the higher the heating temperature, the higher the charge amount tends to be. Usually, the heat treatment is performed at a temperature of 100 ° C to 300 ° C for 10 minutes to 5 hours.

After the heat treatment, the carriers may adhere to each other, so that stress may be applied to loosen the carrier particles.

A developer is prepared by combining the toner and the carrier suitably used in the present invention, and the ratio of the toner having a particle diameter of 12 μm to less than 16 μm in the developer and the specific charge of the toner are as follows: In order to satisfy the above formula (1), it is preferable to use a heat-treated resin-coated carrier as the carrier.

The weight ratio of the toner containing the colored resin particles to the resin-coated magnetic carrier is not particularly limited, but usually 0.5 to 0.5 parts per hundred parts by weight of the carrier.
10 parts by weight.

[0113]

The present invention will be described below in more detail with reference to Examples and Comparative Examples. In the following, numerical values in the composition table represent "parts by weight". An example of the synthesis of the binder resin used in preparing the toner first is shown below.

The particle size distribution was calculated using A of Formula (1) using a Multisizer (manufactured by Coulter), and the charge amount of the toner was calculated using B of Formula (1) using an E-spurt analyzer (manufactured by Hosokawa Micron). I asked. Details of the conditions are as follows.

(Measurement conditions) ・ Developer preparation conditions: ・ Mixing ratio: toner / carrier = 3/97 (weight ratio) ・ Mixing container: made of polypropylene having a diameter of 5 cm and a height of 6 cm ・ Mixing conditions: Stroke 3 cm, 1 minute 790 rotation vibration, mixing time 3 minutes ・ Measurement conditions: ・ E-spurt analyzer ・ Toner blow pressure: 0.05 MPa ・ Count particle count :: 1000 ・ Electrode potential difference between electrodes: 100V Particle size range of toner by E-spurt analyzer The specific charge of each was measured. The particle size distributions measured by the Multisizer and the E-Spurt analyzer are almost the same.

(Synthesis of Linear Polyester A) Terephthalic acid: 332 parts by weight Isophthalic acid: 332 parts by weight Polyoxypropylene- (2.2) -2,2-bis (4-hydroxyphenyl) propane: 1500 Parts by weight were placed in a four-necked flask equipped with a stirrer, a condenser and a thermometer, and 4 parts by weight of tetrabutyl titanate was added under a stream of nitrogen gas. For 15 hours at normal pressure. Thereafter, the pressure was sequentially reduced, and the reaction was continued at 5 mmHg. The reaction was followed by a softening point according to ASTM E28-517, and the reaction was terminated when the softening point reached 95 ° C. The molecular weight of the obtained linear polyester was Mw: 9500,
Mw / Mn: 3.1, softening point: 96 ° C., acid value: 4, Tg by DSC measurement: 63 ° C.

(Synthesis of Crosslinked Polyester B) Terephthalic acid: 332 parts by weight Isophthalic acid: 332 parts by weight Polyoxypropylene- (2.2) -2,2-bis (4-hydroxyphenyl) propane: 700 parts by weight Part: Trimethylolpropane: 80 parts by weight Ethylene glycol: 130 parts by weight is placed in a four-necked flask equipped with a stirrer, a condenser, and a thermometer, and 4 parts by weight of tetrabutyl titanate is added under a stream of nitrogen gas. The reaction was carried out at 240 ° C. for 10 hours under normal pressure while removing the water generated by the dehydration condensation. Thereafter, the pressure was sequentially reduced, and the reaction was continued at 5 mmHg. The reaction was followed by a softening point according to ASTM E28-517, and the reaction was terminated when the softening point reached 151 ° C.
The obtained crosslinked polyester has a THF insoluble content of 5%,
The molecular weight of the F-soluble component is Mw: 180000, Mw / M
n: 48, softening point: 153 ° C., acid value: 4, DS
Tg according to the C measurement method was 65 ° C. The THF-insoluble content was determined by taking 1 g of the synthesized resin powder on a special filter paper and refluxing for 8 hours with a Soxhlet reflux apparatus using THF as a solvent.

(Example 1) <Production of Toner>-Linear polyester A: 33 parts by weight-Crosslinked polyester B: 67 parts by weight-Carbon black-Black Pearls L (manufactured by Cabot Specialty Chemicals, Inc.): 5 Parts by weight ・ Charge control agent (positive charge control agent) ・ Nigrosine dye ・ Bontron N-07 (Orient Chemical Industry Co., Ltd.)
): 2 parts by weight-Quaternary ammonium salt compound-Bontron P-51 (Orient Chemical Industry Co., Ltd.)
1 part by weight ・ Wax ・ Purified carnauba wax No. 1 (acid value 5, manufactured by Celalica NODA): 2 parts by weight are mixed with a Henschel mixer and kneaded with a twin-screw kneader. The kneaded material thus obtained was pulverized, and then 12 μm
Classification was performed so that the volume% of the particle diameter of less than 16 μm was 13.0% to obtain a toner base material A ′.

The above-mentioned toner base material A ': 100 parts by weight Silica HDK3050EP (Wacker Chemicals Co., Ltd.): 1 part by weight was mixed with a Henschel mixer, followed by sieving to obtain toner A ".

<Adjustment of Developer> ・ Toner A ″: 3 parts by weight ・ Carrier (silicone resin-coated ferrite carrier)
J: 97 parts by weight were mixed and stirred to prepare a developer A.

The carrier J is a carrier produced by applying a silicon resin to ferrite particles and then subjecting the coated resin to a heat treatment at 250 ° C. for 10 minutes to crosslink the coating resin.

In the same manner, a toner was prepared in the same manner as in Table 1, and the developer B (Example 2), the developer C (Example 3), and the developer E in the same manner as the developer A (Example 1). (Example 5) A developer F (Comparative Example 1) was produced.

With respect to the developer D (Example 4), a toner was prepared in the same manner as in Example 3 with the composition shown in Table 1, and then the carrier (fluoroacrylic resin-coated magnetite carrier) was prepared.
Except that K was used, it was manufactured in the same manner as in Example 1.

Carrier K is a carrier produced by applying a fluoroacrylic resin to magnetite particles and then subjecting the coated resin to a cross-linking treatment by heating at 250 ° C. for 10 minutes. <Adjustment of Developer D>-Toner C ": 3 parts by weight-Carrier (fluoroacrylic resin-coated magnetite carrier) K: 97 parts by weight

A developer G (Comparative Example 2) was manufactured in the same manner as in Example 3 except that the same toner as in Example 3 was used and a carrier (silicone resin-coated ferrite carrier) L was used.

The carrier L is a carrier processed under the condition that the heat treatment temperature is lower by 50 ° C. than that of the carrier J. <Adjustment of developer G>-Toner C ": 3 parts by weight-Carrier (silicone resin-coated ferrite carrier)
L: 97 parts by weight

The particle size ratio (A) of 12 to 16 μm was determined from the numerical value of volume% by measuring the particle size distribution with a multisizer.

Table 1. Recipe

[Table 1] TP-302; manufactured by Hodogaya Chemical

Further, with respect to the developers obtained in the above Examples and Comparative Examples, the charge amount distribution of the toner was measured using an E-spurt analyzer, and the particle size and the specific charge amount at each particle size were measured. The Q / M (B) of each toner having a toner particle diameter of 12 to 16 μm was determined. The results are summarized in Table 2.

Table 2.

[Table 2]

Thus, it can be seen that Examples 1 to 5 satisfy Expression (1), while Comparative Examples 1 and 2 do not.

Using the above developer, continuous printing of 300 m on continuous paper was performed by a printer for positively charged toner at a speed of 4.5 m / min, and the toner scattering state inside the developing device after 100 m printing and after 300 m printing. Was visually observed. Table 3 shows the observation results.

Table 3.

[Table 3] ：: No scattering is observed at all △: Little scattering is observed, but toner stain is observed when the inside of the apparatus is wiped with a rag ×: In-machine scattering can be confirmed visually ××: Severe in-machine scattering can be confirmed

As described above, in Examples 1 to 5, toner scattering was small and good, whereas in Comparative Examples 1 to 3, toner scattering was large and the inside of the developing device was soiled.

[0135]

As described above, according to the present invention, in a developer for developing an electrostatic charge image comprising a magnetic resin and a colored resin fine particle containing at least a binder resin and a colorant, the colored fine particle has the formula ( Since 1) is satisfied, it is possible to obtain an image with less toner scattering, less dirt inside the apparatus even during long-term continuous use, and less contamination (fog) of a printed image due to toner scattering. Particularly, the electrostatic image developer containing the colored resin particles (toner) satisfying the formula (1) is a developer for a developing device that performs high-speed printing at a speed exceeding 20 m / min, and more preferably at a speed exceeding 30 m / min. Can be used effectively.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 9/10 352 354 (72) Inventor Toshiro Furukawahara 5085-1 Iwatsuki, Iwatsuki-shi, Saitama (72) Inventor 3-5-11 Honcho, Ageo-shi, Saitama F-term (reference) 2H005 AA01 AA06 BA06 CA02 CA08 CA11 CA12 CA14 CA22 CA30 DA03 EA01 EA03 EA05 EA06 2H077 AD02 AD06 AE06 EA03

Claims (13)

[Claims] 1. A developer for developing an electrostatic charge image comprising a colored resin particle containing at least a binder resin and a colorant, and a magnetic carrier, wherein a particle diameter of the developer is 1%.
The ratio of the colored resin particles having a size of 2 μm or more and less than 16 μm and the specific charge amount of the colored resin particles are determined by the following formula (1): 5.18 + 0.12 × A <B −− (1) (where A is a particle) The ratio (volume%) of the colored resin particles having a diameter of 12 μm or more and less than 16 μm is shown.
Specific charge Q / M of colored resin particles having a particle size of less than 6 μm (μC /
g). A developer for developing an electrostatic image. 2. The developer according to claim 1, wherein the binder resin is a polyester resin. 3. The developer according to claim 1, wherein the binder resin is a resin obtained by combining a linear polyester resin (i) and a crosslinked polyester resin (ii). 4. A mixing ratio (weight ratio) of the linear polyester resin (i) and the crosslinked polyester resin (ii).
4. The developer according to claim 3, wherein (i) / (ii) = 2/8 to 8/2. 5. The linear polyester resin (i) has a softening point of 80 ° C. to 120 ° C., a weight average molecular weight (Mw) of 7000 to 12000, a weight average molecular weight and a number average molecular weight (Mn). 5. The developer according to claim 3, wherein the ratio (Mw / Mn) is 4 or less. 6. The crosslinked polyester resin (ii) has a softening point of 130 ° C. to 180 ° C. and a weight average molecular weight (Mw) of a component soluble in tetrahydrofuran of 100.
The developer for developing an electrostatic image according to claim 3, wherein the ratio (Mw / Mn) of the weight average molecular weight to the number average molecular weight (Mn) is 10 or more. 7. The developer for developing an electrostatic charge image according to claim 1, further comprising a release agent. 8. The developer for developing an electrostatic image according to claim 1, further comprising a charge control agent. 9. The developer according to claim 8, wherein the charge control agent contains a nigrosine dye and / or a quaternary ammonium salt compound. 10. The method according to claim 9, wherein the quaternary ammonium salt compound is at least one selected from compounds represented by the following general formula (1), (2) or (3). Developer for developing electrostatic images. <General formula (1)> [Wherein, R _{1 to} R ₃ represent a CnH2n + 1 group. Where n
Represents an integer of 1 to 10. Further, R _{1 to} R ₃ may be the same or different. <General formula (2)> Wherein R ₁ , R ₂ , R ₃ and R ₄ are each independently a hydrogen atom, an alkyl or alkenyl group having 1 to 22 carbon atoms, an unsubstituted or substituted aromatic group having 1 to 20 carbon atoms, Represents an aralkyl group having 7 to 20 carbon atoms, A ^- is a molybdate anion or a tungstate anion,
Represents a heteropolyacid anion containing molybdenum or tungsten atoms. <General formula (3)> Wherein m represents 1, 2 or 3, and n represents 0, 1
Or 2, and M is a hydrogen atom or a monovalent metal ion. X and Z each represent 1 or 2, and Y represents 0 or 1. Further, when X = 1, Y = 1 and Z = 1, and when X = 2, Y = 0 and Z = 2. R _{5 to} R ₁₂ are hydrogen, a linear or branched saturated or unsaturated alkyl group having 1 to 30 carbon atoms, an alkoxylene group having 1 to 4 carbon atoms, or a general formula (-C 2-5 alkylene-O ) N-R
(Where R is hydrogen or an alkyl group or acyl group having 1 to 4 carbon atoms, and n is an integer of 1 to 10), wherein R ₁ , R ₂ ,
R ₃ and R ₄ are hydrogen, a linear or branched saturated or unsaturated alkyl group having 1 to 30 carbon atoms, or a general formula (—CH ₂ —CH ₂ —O) n—R (however, R is hydrogen or an alkyl group or an acyl group having 1 to 4 carbon atoms, and n is an integer of 1 to 10), an oxyethyl group represented by the formula: and a mononuclear or polynuclear alicyclic group having 5 to 12 carbon atoms. Residue, mononuclear or polynuclear aromatic residue or araliphatic residue. ] 11. A silicone resin, a fluororesin,
A resin-coated magnetic carrier coated with at least one resin selected from (meth) acrylic resins, wherein the resin-coated magnetic carrier is used.
0. The developer for developing an electrostatic image according to 0. 12. The method of claim 1, 2, 3, 4, 5, 6, 7,
An image forming method, wherein the developer for developing an electrostatic image according to any one of 8, 9, 10, and 11 is developed at a speed of 20 m / min or more. 13. The method of claim 1, 2, 3, 4, 5, 6, 7,
An image forming method, wherein the developer for developing an electrostatic image according to any one of 8, 9, 10, and 11 is developed at a speed of 30 m / min or more.