JPH021873A - Binary dry developer for reversal development and image forming method - Google Patents

Abstract

PURPOSE:To prevent scattering of a toner and fogging due to uneven triboelectrification amount by using a developer composed of a toner containing a specified binder resin and a Zn-Cu type ferrite carrier having specified characteristics and specifying the triboelectrification amount range. CONSTITUTION:The binder resin of the toner is made from a 50-70wt.% monomer represented by general formula I and a 50-30wt.% monomer represented by general formula II and another 0-30 copolymerizable monomer, and in formulae I and II, R1 is H or methyl; R2 is H or 1-4 C alkyl; R3 is H or methyl; and R4 is 1-12 C alkyl. This resin has a softening point of 110-180 deg.C and a glass transition point of 55-90 deg.C, and it contains a specified copolymer. The developer comprises the toner containing said resin in an amount of 71.0-94.4wt.% and a colorant in an amount of 5.0-15.0wt.% and the like and having a structural viscosity coefficient of 1.0-2.0 and the like, and the Zn-Cu type ferrite carrier having an apparent density of 2.6-3.0g/cm<2> and the like, and the developer has a saturated triboelectrification value of -10 to -36muC/g.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a developer for electrostatic recording and electrophotography, and an image forming method using the same, and in particular, to a developer for electrostatic recording and electrophotography, and particularly to a developer for forming a latent image formed on an organic photoconductor. The present invention relates to a dry two-component developer for reversal development useful for visualization and reversal development using a magnetic brush method, and an image forming method using the same.

(Prior Art) As a dry developing method for an electrostatic latent image, the cancade method and the magnetic brush method are well known. The magnetic brush method.

Using a two-component developer consisting of magnetic carrier particles and toner particles, a brush is formed by magnetic force around a rotating magnetic roll, and in the magnetic brush rotating nine times, a desired image is generated by friction between the magnetic carrier particles and toner particles. This is a method of developing a latent image on a recording medium by attracting polarized toner particles to the latent image on the recording medium.

The reversal development method is described in "Electronic Photography J (written by R, M Shirt Art).

As described on page 25 of Hide Inoue (Supervised Translation, Kyoritsu Shuppan), the electric charge portion induced in the non-image area of the electrostatic latent image due to the peripheral electric field effect is This is a method of developing with a toner of the same polarity as the electric charge, and is said to be advantageous for developing line images with a charge density of 1%.

By the way, in recent years, photoconductive materials have changed from conventional inorganic materials such as amorphous selenium, zinc oxide, titanium oxide, and cadmium sulfide to those that have no toxicity problems and are transparent, flexible, and lightweight. There has been a remarkable shift to organic photoconductive materials, which are superior in quality and can be manufactured at low cost.

A photoconductor made of a photoconductive substance has a photosensitive layer formed on a conductive layer, but organic photoconductors have recently developed a method for functionally separating the charge generation layer and the charge transport layer, which have excellent sensitivity. The mold has been prized. Generally, the organic compounds that generate charges and are contained in the charge generation layer include azoxybenzene-based, disazo-based, trisazo-based, and penzimigsol-based.

Polycyclic quinoline series, indigoid series, quinacridone series,
Phthalocyanine-based, perylene-based, methine-based pigments, etc. are known (Japanese Patent Laid-Open No. 47-37543, JP-A-4
7-37544, JP-A-47-18543 2% JP-A-47-18544, JP-A-48-439
No. 42, JP-A-48-70538, JP-A-4
9-1231 Publication 9% Publication No. 1987-105536, Japanese Patent Application Publication No. 75214-1980, Japanese Patent Publication No. 50-927
Publication No. 38), pyrazoline derivatives (Journal of Photographic Science and Engineering) as organic compounds that transport charges contained in the charge transport layer.
rapic 5science and engine
ering ) Vol. 21, No. 2, p. 73 1977),
Oxazole derivatives (JP-A No. 55-35319 9)
% Publication No. 1987-87557 and Japanese Patent Publication No. 58-182
640), hydrazone derivatives (JP-A-54-59)
143, JP-A-54-150128 and JP-A-55-46760), enamine derivatives (Journal of Imaging Science)
l of Imaging 5science L 2nd
9, No. 1, p. 7, 1985).

In addition, polycarbonate resin is used as a binder resin to fix these organic compounds to the support material.

Esterified polycarbonate resin, silicone resin.

Known resins such as styrene resin, styrene/acrylic resin, polyamide resin, polyester resin, and polyvinyl butyral are used.

(Problem to be solved by the invention) By the way, a copying machine that applies electrophotography and electrostatic recording technology,
The developer used for printers, facsimiles, etc.
There are several characteristics that should be provided as described below.

(1) The print density is sufficiently high and there is no toner adhesion to the background of the print (hereinafter referred to as fog).

(2) There is a need to speed up information processing.

Even in high-speed printing, the print quality mentioned in (1) must be maintained.

(3) Demonstrating stable performance with little deterioration in print quality even after repeated use over a long period of time.

(4) In combination with an organic photoconductor, the above (1) to (3)
).

(5) Even in high-speed printing, the toner image must be firmly fixed to the image support.

However, conventional developers have not been able to satisfy all of these requirements, and an early solution has been strongly desired.

The present invention solves the above-mentioned problems, and enables high printing density even when using an organic photoconductor.

Our first priority is to provide a developer that provides high print quality with less fog.
The purpose of

A second object of the present invention is to provide a developer that provides high print quality in ultra-high speed printing.

Furthermore, the present invention is suitable for repeated use over a long period of time.

A third objective is to provide a developer that causes less deterioration in print quality.

Furthermore, a fourth object of the present invention is to provide a developer that provides excellent fixing properties in ultra-high speed printing.

(Means for Solving the Problems) In other words, the present invention consists of (a) general formula (I); (in formula 9, R0 is hydrogen or a methyl group, and R1 is hydrogen or an alkyl group having 1 to 4 carbon atoms; monomer represented by )
50-70 heavy f.

(b) General formula (■): Monomer represented by CI (!=C(II) 0OR4 (wherein R3 in formula 9 is hydrogen or a methyl group, and is an alkyl group having 1 to 12 carbon atoms) 50-300-30% by weight c) Other copolymerizable monomers 0-30% by weight 0.7 dl/g), residual monomer and/or residual solvent content is 0.1
Binder resin (a) containing a copolymer that is 5% by weight or less
71.0-94-4% by weight metal-containing azo dye (b) 0.5-4.0ffii1 Colorant (C
) 5 to 15.0% by weight and mold release agent (d) 0.1 to 10.0% by weight
, the structural viscosity index N is 1.0-2.0, and the constant α representing the structural viscosity is 8.0X10''~3.0X10-
'Toner (3) has an apparent density of 26 to 3.09.
/Cm3. Z whose saturation magnetization is 60 to 70 emμ/g
n-Cu type ferrite carrier 03), and the saturation value of the amount of triboelectric charge expressed as the amount of charge per gram of toner is -
The present invention relates to a dry two-component developer for reversal development having a temperature of 10 to -36 μC, and an image forming method using the same.

In the present invention, the binder resin which is the (al component) is a monomer represented by the general formula (Il [component (a)] 50 to 70
% by weight, the monomer represented by the general formula [11] [component (b) 350 to 30 wt % and other copolymerizable monomers [(c) component 30 to 30 wt %] Manufactured.

Examples of the component (a) are styrene, α-methylstyrene, p-methylstyrene, p-tert-7”
Examples include f-lustyrene. (b) Examples of ingredients are:

Methyl methacrylate, ethyl methacrylate, 511n-propyl methacrylate, isobrobyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-hentyl methacrylate, isopentyl methacrylate, neopentyl methacrylate, 2-methacrylate - Methylbutyl, n-hexyl methacrylate and its isomers, n-nonyl methacrylate and its isomers, n-decyl methacrylate and its isomers, n-dodecyl methacrylate and its isomers, methyl acrylate,
Ethyl acrylate, n-propyl acrylate, 51in-butyl acrylate, isobutyl acrylate, n-octyl acrylate, dodecyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, phenyl acrylate and their isomers etc. can be opened. Examples of components (c) include glycidyl methacrylate, methoxyethyl methacrylate, propoxyethyl methacrylate, butoxyethyl methacrylate, methoxydiethylene glycol methacrylate, ethoxydiethylene glycol methacrylate, methoxyethylene glycol methacrylate, butoxide IJ ethylene glycol methacrylate. , methoxydipropylene glycol methacrylate, phenoxy7-ethyl methacrylate, phenoxydiethylene glycol methacrylate, phenoxytetraethylene glycol methacrylate, benzyl methacrylate,
Cyclohexyl methacrylate, tetrahydrofurfuryl methacrylate, dicyclopentenyl methacrylate, dicyclobentenyloxyethyl methacrylate, N-vinyl-2-pyrrolidone methacrylate.

Methacrylonitrile, methacrylamide, N-methylolmethacrylamide, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, 2-hydroxy-3-phenyloxypropyl methacrylate.

Diacetone acrylamide, acrylic acid, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, pentyl acrylate.

Hexyl acrylate, heptyl acrylate, octyl acrylate, nonyl acrylate, decyl acrylate, undecyl acrylate, dodecyl acrylate, glycidyl acrylate, methoxyethyl acrylate, propoxyethyl acrylate, butoxyethyl acrylate, acrylic acid Methoxydiethylene f IJ Cole, ethoxydiethylene glycol acrylate, methoxyethylene glycol acrylate, butoxytriethylene glycol acrylate, methoxydipropylene glycol acrylate.

Phenoxyethyl acrylate, phenoxydiethylene glycol acrylate, phenoxytetraethylene glycol acrylate, benzyl acrylate, cyclohexyl acrylate, tetrahydrofurfuryl acrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, N-vinyl acrylate -2-pyrrolidone, hydroxyethyl acrylate, hydroxy-7probyl acrylate, hydroxybutyl acrylate, 2-hydroxy-3-phenyloxypropyl acrylate, glycidyl acrylate, acrylonitrile.

Acrylamide, N-methylolacrylamide.

Diacetone acrylamide, vinylpyridine, morpholinoalkyl (meth)acrylate, aziridylalkyl (methane acrylate, piperazyl (meth)acrylate, piperidyl (meth)acrylate, morpholinoalkyl (methaneacrylamide, aziridylalkyl (meth)acrylamide, piperadylalkyl) (meth)acrylamide, piperidyl alkyl (meth)acrylamide.

Morpholinoalkylthio(methane acrylate, aziridylalkylthio(meth)acrylate, piperadylargylthio(meth)acrylate, piperidylalkylthio(meth)acrylate, N-vinylvirol, N-
Cyclic amine group-containing monomers such as vinyl carbazole, N-vinylindole, N-vinylpyrrolidone, dimethylaminoethyl acrylate, diethylamine acrylate, dimethylamine propyl acrylate, dimethylaminomethyl methacrylate, diethylaminoethyl methacrylate, dimethylaminopropyl methacrylate, etc.
Acyclic amino group-containing monomer of α-methylene aliphatic monocarboxylic acid aminoalkyl ester.

0=C I 5Hsy CH= CH Cs)(? Maleimi such as do-based monomer.

CH Tomi CH CH=　CH 5Hss H H, C4-0-C=CH 0 mountain CH=CH (CHHz)y C=0 aHs General Niishi): A compound represented by

for example.

[In the formula, R6' represents hydrogen or a methyl group, h' represents an alkylene group having 1 to 6 carbon atoms, or a divalent organic group having an alicyclic ring or an aromatic ring, and R1' and R41 are each independently an alkyl group having 1 to 6 carbon atoms or the formula: (wherein R and l represent an alkyl group having 1 to 6 carbon atoms, g
I (@' represents an alkylene group having 1 to 6 carbon atoms, n is the number of substituents of R, /, represents an integer of 0 or 1 to 5, and 2m is the number of substituents of ya', O or 1 to (represents an integer of lO), the total number of carbon atoms of R4' and R3+ or R, / shall be 4 or more, and R3' and B
Examples of 4+ include compounds having one vinyl group in one molecule, which may be the same or different.

In addition, as substances having two or more vinyl groups in one molecule, divinylbenzene, reaction products of glycol and methacrylic acid or acrylic acid 1, such as ethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1, 4-butanediol dimethacrylate, 1,5-bentanediol dimethacrylate, 1,
6-hexanediol diacrylate, neopentyl glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate)
Polyethylene glycol diacrylate, hydroxypivalic acid neopentyl glycol ester dimethacrylate, trimethylolethane trimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, trismethacryloxyethyl phosphate, bis (methacryloyloxyethyl) hydroxyethyl isocyanurate, tris(methacryloyloxyethyl)in cyanurate, ethylene glycol diacrylate, 1.3-butylene glycol diacrylate, 1.4-butanediol diacrylate, 1.5-bentanediol diacrylate Acrylate, 1
, 6-hexanediol diacrylate, neopentyl glycol diacrylate.

Diethylene glycol diacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate, tripropylene glycol diacrylate, hydroxypiparate neopentyl glycol diacrylate, trimethylolethane triacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, penta Erythritol tetraacrylate, trisacryloxyethyl phosphate,
Bis(acryloyloxyethyl)hydroxyethyl isocyanurate, tris(acryloyloxyethyl)
Use of isocyanurate, half-esterified product of glycidyl methacrylate and methacrylic acid or acrylic acid, half-esterified product of bisphenol-type epoxy resin and methacrylic acid or acrylic acid, half-esterified product of glycidyl acrylate and methacrylic acid or acrylic acid, etc. You can also do it.

Each of the above components contains component (a) in an amount of 50 to 70% by weight.

Preferably 55 to 65% by weight, component (b) 50 to 30%
% by weight, preferably 45 to 35% by weight, and component (c) is blended in an amount of θ to 30% by weight and double-polymerized. Outside this range, the performance, lifespan, rapid fixing ability at low temperatures, etc. of the developer cannot be satisfied. The blended monomers can be polymerized in solution, suspension, or in bulk.

Copolymerization can be carried out by any method such as emulsion polymerization, but suspension polymerization and solution polymerization are particularly preferred from the viewpoint of adjusting resin physical properties and workability.

Polymerization initiators used include τ-azobisisobutyronitrile, 42'-azobis(4-dimethylvaleronitrile), 2,2'-azobis(4-methoxy-44
-dimethylvaleronitrile), peroxy esters such as t-butylperoxy(2-ethylhexanoate), t-butylperoxyisobutyrate, 1.1-bis(1-butylperoxy) peroxyketals such as l&5-)rimethercyclohexane, 1,1-bis(t-butylperoxy)cyclohexane, dicumyl peroxide, and 5-dimethyl-2,5-di(t-
Dialkyl peroxide such as (butyl peroxy)hexane, benzoyl peroxide.

Examples include diacyl peroxides such as acetyl peroxide. These are preferably used in an amount of 0.5 to 10% by weight based on the total monomers.

When carrying out suspension polymerization, a dispersion stabilizer such as polyvinyl alcohol, sodium polyacrylate, calcium phosphate, calcium carbonate, bentonite, etc. is used. These dispersion stabilizers are dissolved in water or the like and used as a dispersion medium.

Solvents used for solution polymerization include benzene,
Toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, butyl acetate, ethylene glycol monoethyl ether.

Known compounds such as ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol mobutyl ether, ethanol, furopanol, butanol, hexanol, cyclohexanone, aliphatic hydrocarbons, and the like can be used alone or in combination of two or more.

The resulting copolymer has a softening point of 130 to IS.

°C preferably 130-150 °C, glass transition temperature 55
~90℃, preferably 60~85℃, reduced viscosity 0.2~
0.7dl! /9 Preferably 0.25 to 0.4 dl! /
9, and the content of residual monomers and/or residual solvents is adjusted to be less than o, xsffit%, preferably less than 0.1% by weight, based on the total copolymer. The softening point in the present invention is measured by the ring and ball method described in JIS K2531. In addition, the glass transition temperature is determined by thermomechanical analysis 0 penetration (Th
emo-mechanica 1 analysis
It was measured using the penetration method under the conditions of a load of 709 f and a temperature increase rate of 10° C./min.

As a measuring device for such glass transition temperature.

It is commercially available as TMS-1 from Perkin Elma. The reduced viscosity is o, sal! /g) toluene solution.

It was measured at 30°C. Residual monomer and/or
Alternatively, the amount of residual solvent can be measured by gas chromatography or the like. for example.

A calibration curve for each monomer or solvent is prepared by gas chromatography, and the copolymer is dissolved in a certain amount of solvent and subjected to gas chromatography. Residual solvent can be quantified. In addition, in the example mentioned later.

It was quantified using this method.

The copolymer must exhibit a softening point, glass transition temperature, reduced viscosity, and residual monomer and/or residual solvent content within the above ranges.

If any one characteristic falls outside the above range.

This would impair the features of the present invention shown below, and furthermore, it would be difficult to produce the toner and the toner would have poor quick fixing properties at low temperatures.

The features of the present invention are that the toner exhibits remarkable resistance to abrasion and abrasion due to friction with the carrier particles and the inner wall of the developing machine, and furthermore, the toner exhibits remarkable resistance to abrasion and abrasion due to friction with the carrier particles and the inner wall of the developing machine. However, it has the characteristic of exhibiting significant resistance. These features are:

Among the various performances required for the developing agent of the present invention, it is believed that it is particularly advantageous in achieving continuous developability and long life in high-speed development using an organic photoconductor.

As the binder resin (al), other resins may be used in combination.

Other resins include polymers or copolymers of the other polymerizable unsaturated monomers listed above, silicone resins, norbornene polymers, polyester carbonates, xylene resins, epoxy resins, diene resins, polyester resins, and phenol resins. , coumaron resin, coumaron-indene resin, amide resin.

Amide imide resin, butyral resin, amine resin.

Urethane resin, terpene resin, ketone resin, ionomer resin, rosin and modified resins of these, etc.

Known resins can be used, and these are preferably blended in the toner in an amount of 0 to 30% by weight.

The metal-containing azo dye which is the component (b) in the present invention is as follows.

(In the formula, T, Y, and Z represent hydrogen, halogen, carboxyl group, hydroxyl group, nitro group, sulfone group, or sulfonamide group, and Me represents Cr and Zn.

Person 1. Indicates Co or Fe, and 9M is hydrogen and potassium.

Examples include compounds represented by sodium or fatty acid ammonium). Such metal-containing azo dyes are
Because the bulk specific gravity is extremely small and the surface area is extremely large,
It has good compatibility with the copolymer which is component (a) and has excellent bidispersity. Therefore, a uniformly chargeable toner can be obtained. This feature is effective in reducing toner scattering and fogging, which is 9% of the performance required for the developer of the present invention, and is advantageous in achieving a longer service life.

Examples of the metal-containing azo dyes include BONT
RON)・5-31. Bontron・5-32° Bontron・5-34. Bontron S-40 (both trade names, manufactured by Orient Chemical Industry ■).

Aizen, Spiron Black, TRH (AIZENSP
Commercially available products include ILON BLACK TRH (manufactured by Hodogaya Chemical Co., Ltd.).

In the present invention, as the colorant (C1 component), any colorant can be used as long as the amount of charge of the developer is maintained within a desired range.A typical colorant that is effective in the present invention is carbon black. An example of this is a larpen (几av
en) 150 (manufactured by Columbia Carbon), carbon black MA-8, carbon black MA-100
, carbon blackna 44. Power - Pump racker 3
0 (both made by Mitsubishi Kasei ■), Monarch 1000 (MO
looo (1000), MOGUL L
, Regal 400-R (REGAL40OR,),
BLACK PEARLS
L) (Both are CABOTT CORPOR,
manufactured by ATION). Others 9 For example, the following color-adjusting dyes and pigments can also be used. Specifically, yellow lead, cadmium diro yellow iron oxide, titanium yellow, naphthol yellow,...Nza yellow, pigment yellow
Yellow colorants such as benzidine yellow permanent yellow, quinoline yellow lake, anthrapyrimidine yellow,
Permanent orange, Palkan first orange,
Orange coloring agents such as benzidine orange and indanthrene frilliant orange, brown coloring agents such as amber iron, amber permanent brown, red iron oxide, antimony powder, permanent red, and fire red.

Brilliant Carmine, Light Fast Red Toner Permanent Carmine, Pyrazolone Red, Bordeaux, Heliobordeaux Red colorants such as Rhodamine Lake, Thioindigo Red, Thioindigo Reddon, Purple colorants such as Cobalt Purple, Fast Violet, Dioxazine Violet, Cobalt Blue Blue coloring agents such as cerulean blue, metal-free phthalocyanine blue, phthalocyanine blue indanthremble, and indigo.

There are green colorants such as chrome green, cobalt green, green gold, phthalocyanine green, and polychrome bromine copper phthalocyanine.

In the present invention, the template agent which is the dl component is 9, for example, a low molecular weight polyolefin such as polyethylene or polypropylene, or castawax (manufactured by Ito Oil Co., Ltd.).

Diamond wax (manufactured by Shin Nihon Rika), Hoechst wax E, Hoechst wax OF (and above).

Examples include ester waxes such as Hoechst Akchen Gesellschaft GmbH, carnauba wax, amide waxes such as Hoechst Wax C (manufactured by Hoechst Akchen Gesellschaft GmbH), fatty acid metal salts, and the like.

The toner that is the active ingredient in the present invention includes a binding resin as the component (a) and a metal-containing azo dye as the component (b).

(Produced with the coloring agent as component C1 and the mold release agent as component (d) as essential components,
The ratio of components (C) and (d) is 7 for component (a), respectively.
1.0 to 94.4% by weight, component (b) 0.5 to 4.0
The weight of component (C) must be 5 to 15.0%, and the component (d) must be blended within a range of 0.1 to 10.0% by weight. If any one of them is outside this range, the amount of triboelectric charge of the developer will not be desired, and fogging and scattering will become noticeable. Furthermore, the resulting image suffers from problems such as poor fixing such as occurrence of offset and a decrease in image density.

The toner which is the prisoner component of the present invention is (a), (b), (
C) and (dl component) are essential components, but as long as the amount of triboelectric charge of the developer is maintained within the desired range, known additives may be added.As the additive, hydrophobic silica powder 9 For example, Aerosil R972, Silica D-17, R8
12, RA200H, RX-C (manufactured by Nippon Aerosil ■) and Taranox 500 (manufactured by Tulco)
etc., metal salts of fatty acids 9 such as zinc stearate, fluoropolymers such as FAX FIIO, F113. F
117. F119 (all product names, manufactured by Dainippon Ink)
Those known in the field of electrophotographic recording may be mentioned, and depending on the purpose, they can be added to the toner preferably in a range of 0 to 10% by weight.

The toner which is the component (3) of the present invention is composed of (al, (b)
), (It can be produced by blending components C1 and (d) and additives selected as necessary, melt-mixing at an appropriate temperature, cooling, and then crushing and classifying into a desired particle size distribution.

In addition, it is manufactured by thoroughly dispersing (a), (b), (C) and (dl components and additives selected as necessary) in an appropriate solvent and then removing the solvent by a method such as spray drying. In other words, in the present invention, any known technology can be used to manufacture the toner.

The physical properties of the toner, which is the captive component of the present invention, are the structural viscosity index N
is 1.0-20. Preferably, the constant α representing the structural viscosity is 1.2 to 1.7°.
9. Preferably 1.34 X 10-'-45X10-
'Thermal diffusivity is preferably λOX 10"~7.5X10
-'m2/h 9% preferably 3.2X10-' ~
Adjusted within the range of 4.5X10-' rl/hour.

Here, the structural viscosity index N and the constant α representing the structural viscosity are determined using a capillary flow test device.

The apparent viscosity was measured by changing the shear strain rate stepwise from 6 to 130'' at a constant temperature of 130°C, and the shear strain rate and apparent value were determined from the relationship diagram of viscosity using the following equation.

The above-mentioned capillary type flow test device is commercially available as Toyo Seiki ■ Yoshi Capirograph (trade name).

On the other hand, the above thermal diffusivity can be determined by measuring the temperature change of the toner layer by radiant heating the toner with a halogen lamp using the apparatus shown in Figure 1, and from the obtained values, a one-dimensional heat conduction equation can be calculated. It can be obtained by solving approximately.

If you use a toner with the above characteristics, the heat during fixing,
Easily deformed under pressure and high shear velocity.

It is thought that this enables rapid fixing at low temperatures.

If it is outside these ranges, good fixing properties cannot be obtained.

Note that the range of the toner particle size is preferably 5 to 25 μm.

If the particle size is outside this range, it tends to cause a decrease in image clarity and an increase in fog density.

The Zn-Cu-based ferrite carrier which is the component (B) in the present invention has the following formula (Fe2O3 component and other metal oxide components), general formula (III) (MO-X
(F810m)? It is expressed as Furthermore, MO is Cub
, is a mixture of metal oxides containing ZnO as an essential component. Here, it is preferable that the amount of Zn0 is not too large. Z
As the amount of nO increases, the Curie temperature tends to decrease. Fs in Zn-Cu ferrite carrier
What is the molar ratio of component 403 and other metal oxide components?

latter/former (same as X/Y in general formula (III),
(hereinafter simply expressed as X/Y) is preferably 0.42 to 0.85. When X/Y is less than 0.42, the saturation magnetization of the carrier tends to be less than 40 emu/g, which tends to cause a decrease in image quality. When X/Y exceeds 0.85, the life of the developer tends to decrease. .

In the present invention, the Zn-Cu-based ferrite carrier (which is the Bl component) has an apparent density of 26 to 3.06/cm.
.

The value of saturation magnetization is preferably adjusted to z7 to Z99/Cl11'', and the value of saturation magnetization to be 60 emu/g to 7 Q emu/g, preferably 52 to 65 emu/g.

The apparent density is 2, but outside the above range the image quality is degraded.

If the saturation magnetization exceeds 70 emu/, the life of the developer will decrease, and the life of the developer will decrease.6 Q emu/g
If it is less than this, carrier scattering and image quality deterioration occur.

Here, the apparent density in the present invention is JIS Z250.
It was measured by the method described in 4. In addition, the saturation magnetization was measured using a sample vibrating magnetization measuring device, so such a measuring device is available from RIKEN Electronics Ltd.
It is commercially available as Tracer (trade name). This Zn-Cu-based ferrite carrier has softer magnetic properties and a nearly smooth surface compared to commercially available Ni-Zn-based ferrite carriers and iron powder, which are commonly used in conventional high-speed printers and general office copiers. Due to these features, the contact of the developer to the electrophotographic photoreceptor having an organic photoconductive layer is soft, and the mixing torque is small. It has the feature of exhibiting a high degree of toner abrasion and abrasion prevention effect, and these features are considered to work effectively in achieving development, continuous developability, and long life of the present invention.

It is preferable that the Zn--Cu type ferrite carrier which is the component (B) in the present invention has a particle content of 90% by weight or more having a particle size of 37 to 177 μm. Among the various performances required of the developer of the present invention, the carrier particle size has an effective effect on high print density. Furthermore, the above-mentioned suitable particle size (5 to 2
When used in combination with a toner having a particle diameter of 5 μm), a particle size within this range is preferable because toner scattering and carrier scattering can be reduced.

The zn-cu type ferrite carrier which is the component (8) in the present invention can be produced, for example, as follows.

A suitable amount of a metal oxide containing ferric oxide Fe103, Cub, and ZnO as essential components is blended, and the slurry obtained by grinding and mixing with a wet ball mill or wet vibration mill is dried, and after further grinding, 700 ~ Complete calcination is performed at 1000°C. After calcination, it is further processed by wet ball mill, wet vibration mill, etc. for 20 minutes.
After pulverizing to micrometers or less, granulation is carried out at 1050-1500℃.
Hold for 2 to 24 hours. This fired product is crushed and classified. If necessary, reduction is performed and the surface is further oxidized. Furthermore, if necessary, a resin coating is performed.

Although it is manufactured by such a process, it is not limited to the above-mentioned example, and any known technique can be used.

The saturation value of the triboelectric charge amount of the developer according to the present invention expressed as a charge per gram of toner is -10.0 to -36 .mu.C, preferably -ILO to -25.0 .mu.C.

ζ In the present invention, the amount of triboelectric charge of the developer means the saturation value of the amount of charge measured by the blow-off method, and represents the amount of charge per 1 g of toner. The device used for this measurement is 2, for example, Toshiba blow-off charge measuring device TB-200.
It is commercially available as (Toshiba Chemical ■ trade name). If the amount of triboelectric charge of the developer is within the above range, high image quality with high line image and large area image density can be obtained, but if the frictional zone xi- of the developer is less than ~10.0 μC, the toner When toner scattering is significant, the image density decreases noticeably, and when the amount of charge exceeds -36.5 μC, there is no toner scattering, but the image density decreases noticeably.

The developer according to the present invention includes (3) the toner as the component and (B) the toner as the component (3).
It is composed of a Zn-Cu type ferrite carrier which is a component, and its proportion is 0.5 to 4.5% by weight of component (3).
and (8) component 95.5 to 99.5% by weight in a total amount of 10
It is preferable to adjust K so that 0 weight * 1C. If the ratio is outside of this range, it will be difficult to adjust the amount of w1 friction band of the developer to a desired range, and this will likely cause fogging and toner scattering.

When the developer according to the present invention is brought into contact with an electrostatic latent image formed on an organic photoconductor, the image is developed, and the image is transferred to a support and fixed. You can get quality images.

As the developing method, two kinds of known developing methods can be applied.

Further, there are two fixing methods, for example, the so-called oil-less method, the oil-coated heat roll method, and the flash method.

Various known methods such as open method and pressure fixing method can be applied.

(Example) Examples of the present invention will be described in detail below, but the present invention is not limited thereto.

Example 1 60 parts by weight of styrene, 4 parts by weight of butyl methacrylate 1 part by weight
2 parts by weight of penzoyl peroxinide as a polymerization initiator, 10 g parts of hydroxide abatai as a suspension stabilizer,
Aqueous medium 20 containing 0.006 parts by weight of sodium dodecylbenzenesulfonate and 0.03 parts by weight of sodium chloride
0 parts by weight and copolymerized by suspension polymerization at a temperature of 80 to 90°C, with a softening point of 140°C and a glass transition temperature of 70°C.
℃, reduced viscosity is 0.3 dl! /1i*Residual monomer is 0.
A copolymer containing 0.055 parts by weight was obtained.

88 parts by weight of the above copolymer as a binder resin, BONTRON S-40 2'IL
7 parts by weight of carbon blackener 40 and 3 parts by weight of carnauba wax were dry mixed together and melt-kneaded at 100 to 160°C using a twin-screw extruder. After cooling the mixed material, it is finely pulverized with jet air until the softening point is 160℃.
, the glass transition temperature is 77°C, the structural viscosity index N is LO, and the constant (hereinafter simply referred to as a constant) α representing the structural viscosity is 1.
43X10-', thermal diffusivity is a6 X 10-'m"
/ hour 9 Toner with a particle size of 5 to 25 μm was produced.

The above toner aO weight part and apparent density are 2,726
7cm3. Saturation magnetization 606 mu/g, 37-177
Almost spherical Zn-Cu based ferrite carrier (X/Y,
0.6) A developer consisting of 97.0 parts by weight was prepared. The amount of triboelectric charge was 25 μC per 1 g of toner.

After uniformly charging an electrophotographic photosensitive drum having an organic photoconductor layer rotating at a circumferential speed of about 70 cm/s with a corona voltage of 6.5 kV, information was written using a He-Ne laser, and the above developer was used to write information. Reversal development was performed using a magnetic brush method. Next, transfer the toner image onto continuous paper and apply pressure (5 kgf/
am'') and a heating (surface temperature of 200° C.) roll fixing device.

As a result, the capri density is O, OS, the print density is 1.2, which is a high density without capri, and the fixing strength is 80%.

A good image without offset was obtained. In addition.

The measurement method is shown below.

Planning method (a) Print density and fog density were measured using a microphotometer model MPM manufactured by Union Optical Co., Ltd.

(b) Fixing strength A tape was applied to the fixed print and then peeled off, and the fixing strength was calculated using the following formula.

(C1 offset resistance The presence or absence of offset was calculated by visual inspection.

Next, continuous development, transfer, and fixing were repeated for 1 million sheets while replenishing toner.

Capri concentration is 0.08. The initial good image with a print density of 1.1 was maintained, and no toner scattering from the developing machine was observed.

Example 2 81 parts by weight of the copolymer obtained in Example 1 as a binder resin,
Bontron Varnish 31 (BONTORON8-31
) 4 parts by weight, carbon black ◆ 4013 parts by weight and Viscoel 660P 2 parts by weight in the same manner as in Example 1 to obtain a softening point of 172°C.

The glass transition temperature is 78°C, the structural viscosity index N is 1.0°, the constant α is 1.43 x 10-', and the thermal diffusivity is 4. lX1
0-'m''/he A toner having a particle size of 5 to 25 μm was prepared.

The above toner has 4.2 parts by weight and an apparent density of 2.72
s/am', saturation magnetization 60 mu/g, 37~17
A substantially spherical Zn--Cu based ferrite carrier (X/Y: 0.
5) A developer consisting of 95.8 parts by weight was prepared. The amount of triboelectric charge was 20 μC per gram of toner.

After uniformly charging an electrophotographic photosensitive drum having an organic photoconductor layer rotating at a circumferential speed of about 70 cm/s with a corona voltage of a 5 kV, information was written using a He-Ne laser, and this was written using the developer described above. υ reversal development was performed using a magnetic brush method. Next, the toner image was transferred to continuous paper, fixed using a pressurized and heated roll fixing device, and evaluated in the same manner as in Example 1. As a result, a good image was obtained with a capri density of O and OS and a print density of 1.3. was gotten. Further, no offset occurred. The fixing strength was 85 yen.

Next, while replenishing toner, continuous development, transfer, and fixing were repeatedly performed on 1 million sheets.

The initial good image was maintained with a Capri density of O and OS and a print density of 1.2. Toner scattering from the developing machine.

Capri and offset etc. did not occur at all.

Example 3 11 parts by weight of styrene 501, 40 parts by weight of butyl methacrylate, 10 parts by weight of methyl methacrylate, and 2 parts by weight of benzoyl peroxide as a polymerization initiator were added to 200 parts by weight of the same aqueous medium as in Example 1.

Copolymerized by suspension polymerization, the softening point is 145℃, the glass transition temperature is 69.0℃, and the reduced viscosity is 0.32dt/
A copolymer having a residual ge monomer of 0.11 times was obtained.

88 parts by weight of the above copolymer, Bontron Varnish 40 (
A softening point of 140°C, a glass transition temperature of 72°C, and a structural viscosity index of N is LSI, constant α is ZOXIO-', and thermal diffusivity is 3.7 x 10-'
A toner having a m2/h9 particle size of 5 to 25 μm was produced.

The above-mentioned toner 2-0 parts by weight and apparent density are Z 72
9/CII+', saturation magnetization 5 Q emu/g,
A substantially spherical Zn-Cu-based ferrite carrier (
X/Y; 0.7) A developer consisting of 9&O heavy parts was prepared. Friction band 1! The amount was -17.6 μC/g of toner.

After an electrophotographic photosensitive drum having an organic photoconductor layer rotating at a circumferential speed of about 70 cm/s was fully charged with a corona voltage of 6.5 kV, information was written using a He-Ne laser, and the drum was written using the developer described above. Reversal development was performed using a magnetic brush method. The toner image was then transferred to continuous paper, fixed using a pressurized and heated roll fixing device, and evaluated in the same manner as in Example 1. As a result, the fog density was 0.08. Print density is 1.4. No capri, high density, good fixing with no offset (
90%) images were obtained. Next, when we repeated continuous development, transfer, and fixing for 1 million sheets while replenishing toner, the initial good image quality with fog density O, OS, and print density 1 and 3 was maintained, and the toner from the developing machine was No scattering, fogging, or offset occurred.

Comparative Example 1 Hymer 5T-120 (trade name, Sanyo Chemical polystyrene, softening point 120°C) 90 parts by weight, Bontron S-3
1 (BONTRON 831) 2 parts by weight.

The softening point was 125 in the same manner as in Example 1 using 5 parts by weight of Monarch 1000 and 1 part by weight of polyethylene wax.
℃, glass transition temperature is 93℃, structural viscosity index N is 1.0
．． Constant α is 9.8 x 10-5. Thermal diffusivity is 1.5
A toner with a particle size of 5 to 25 μm was produced.

3 parts by weight of the above toner and an apparent density of 172 g
/cII+3. Saturation magnetization 5 Q emu/g, 37
A nearly spherical Zn-Cu-based ferrite carrier (X/Y
: 0.5) A developer consisting of 97.0 parts by weight was prepared. The amount of triboelectric charge was -13.2 μC per 1 g of toner.

After uniformly charging an electrophotographic photosensitive drum having an organic photoconductor layer rotating at a circumferential speed of about 70 cm/s with a corona voltage of 6.5 kV, He-Ne laser information was written.

Reversal development was performed using the above developer using a magnetic brush method. The toner image is then transferred to continuous paper.

When the fixing was performed using a pressurized and heated roll fixing device and evaluated, the fog density was 0.08. An image with a print density of 1.4, which was free from fog and had a high density and was free from offset and had good fixability, was obtained. Next, when continuous development, transfer, and fixing were repeated while replenishing toner, the print density significantly decreased to 0.65 after about 0.5 hours.

Comparative Example 2 40 parts by weight of styrene, 55 parts by weight of butyl methacrylate, 5 parts by weight of methyl methacrylate, 1 polymerization initiator, and 2 parts by weight of benzoyl peroxide were added to 200 parts by weight of the same aqueous medium as in Example 1.

Copolymerized using the M shallow type method, the softening point is 125℃,
Glass transition temperature is 55℃, reduced viscosity is 0.28dl/g
, a copolymer containing 0.1% by weight of residual monomer was obtained.

88 parts by weight of the above copolymer, Subiron Black TRH1,
A toner having a softening point of 135° C. and a glass transition temperature μm was produced using 1 part of i[j and 2 parts by weight of polypropylene wax.

The above-mentioned toner ZO31 [31 parts has an apparent density of 2-7]
29/(J”, saturation magnetization 60 emu/g, 37~1
A developer was prepared as V4, which consisted of 930 parts by weight of a substantially spherical Zn--Cu type ferrite carrier having a particle size content of 77 μm at 95.8% by weight or more. Frictional charge amount is 1g of toner
The current temperature was 16.5 μC.

After uniformly charging an electrophotographic photosensitive drum with an organic photoconductive layer rotating at a circumferential speed of about 70 CQl/S with a corona voltage of 6.5 kV, information was written using a He-Ne laser.

Reversal development was performed using the above developer using a magnetic brush method. The toner image was then transferred to continuous paper, and then fixed using a pressure and heat fixing device for evaluation.

Fog density O, OS, print density 1.35. Images with high print density and no fog were obtained. However, an offset occurred. Next, while replenishing toner, only development and transfer were repeated, and the print density decreased at about 0° for 0.5 hours, and toner scattering occurred.

Comparative Example 3 4.2 parts by weight of the toner obtained in Example 1 and an apparent density of 1
5 g/am", specific resistance 5.I x 10'Q.
cm.

Saturation magnetization 70 emu/g, 74-177/j
Almost spherical Ni with a particle size content of m of 98 weights or more
- A developer was prepared from 95.8M of Zn-based ferrite carrier. The amount of triboelectric charge is per gram of toner.

It was -9.2 μC.

After uniformly charging a photosensitive drum rotating at a circumferential speed of about 70 an/S with a corona voltage of 6.5 kV, information was written using a He-Ne laser, and reversal development was performed using the above developer using a magnetic brush method. The toner image was then transferred onto continuous paper, pressed, and fixed using a heated roll fixing device for evaluation. As a result, there was no fog, but the image density was low, with a fog density of 0.09° and a print density of 0.9. Next, I repeatedly performed development, transfer, and fixing while replenishing toner, and found that approximately 20
Fog density α22. The image density decreased significantly to 0.67, and toner scattering began to occur.

Comparative Example 4 The apparent density of the toner ZOJli portion obtained in Example 1 was 23.
g/cx? , saturation magnetization 55 emu/g s 3
Substantially spherical Zn--Cu based ferrite carrier 98. having a particle size content of 7 to 177 μm in an amount of 95.83 or more.
A developer consisting of 0 parts by weight was prepared. The amount of triboelectric charge was -9.5 μC per gram of toner.

After uniformly charging a photosensitive drum rotating at a circumferential speed of 70 crIA/S with a corona voltage of a 5 kV, information was written using a He-He laser, and reversal development was performed using the above developer using a magnetic brush method. The toner image was then transferred to continuous paper and fixed using a pressurized and heated roll fixing device. As a result, carrier scattering and carrier and/or
Otherwise, the developer moved or entrained, and 9 images could not be obtained.

(Effects of the Invention) According to the present invention, it is possible to solve not only the problems of toner scattering and fog caused by non-uniformity of the amount of charge, which have conventionally been problems, but also the problem of fatigue deterioration of the developer. Further, it is possible to perform high-speed and rapid fixing, and at the same time is suitable for electrophotographic photoreceptors having an organic photoconductor layer.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an example of a thermal diffusivity measuring device. Explanation of symbols

Claims (1)

[Claims] 1. (A) General formula (I): ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (However, in the formula, R_1 is hydrogen or a methyl group, and R_2
is hydrogen or an alkyl group having 1 to 4 carbon atoms) (b) General formula (II): ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) (However, , where R_3 is hydrogen or a methyl group, R_4
is an alkyl group having 1 to 12 carbon atoms) and (c) 0 to 30% by weight of other copolymerizable monomers, and has a softening point of 110 to 180. °C, the glass transition temperature is 55 to 90 °C, the reduced viscosity is 0.2 to 0.7 dl/g, and the content of residual monomer and/or residual solvent is 0.1
Binder resin (a) 71 containing a copolymer of 5% by weight or less
．． 0 to 94.4% by weight Metallic azo dye (b) 0.5 to 4.0% by weight Colorant (c
) 5 to 15.0% by weight and a mold release agent (d) 0.1 to 10.0% by weight, the structural viscosity index N is 1.0 to 2.0, and the constant α representing structural viscosity is 8. 0x10^-^5~3.0x10
Toner (A) which is ^-^9 and whose apparent density is 2.6~
3.0g/cm^3, saturation magnetization 60-70emμ/g
A dry two-component developer for reversal development, comprising a Zn-Cu-based ferrite carrier (B), and having a saturation value of triboelectric charge amount expressed in charge amount per gram of toner of -10 to -36 μc. 2. The thermal diffusivity of toner (A) is 2.0×10^-^4 ~
2. The dry two-component developer for reversal development according to claim 1, wherein the developer is 7.5×10^-^4 m^2/hour. 3. Fe_ of Zn-Cu ferrite carrier (B)
The molar ratio of the 2O_3 component and the other metal oxide component is 0.42 (other metal oxide component/Fe_2O_3 component)
The dry two-component developer for reversal development according to claim 1 or 2, wherein the dry two-component developer for reversal development is 0.85. 4. Toner (A) 0.5-4.5% by weight and Zn-Cu
Ferrite carrier (B) 95.5-99.5% by weight
A dry two-component developer for reversal development according to claim 1, 2, or 3. 5. Forming an electrostatic latent image on the organic photoconductor, and then contacting it with a dry two-component developer for reversal development according to claim 1, 2, 3, or 4. An image forming method in which the image is visualized, transferred to a support, and fixed.