JPS63217360A - Developer for latent electrostatic charge image - Google Patents

Abstract

PURPOSE:To improve the fixability of a developer at a low temp., the offsetting and blocking resistances by using a toner based on a specified ionic cross-linked resin and a resin coated carrier. CONSTITUTION:A developer is composed of toner particles based on a resin (B) obtd. by allowing carboxy groups present in a polymer to react with a multivalent metallic compd. (A) and, carrier particles obtd. by coating the surface of a magnetic body with a resin (C). The metal of the compd. A is preferably a zinc family metal such as Zn or an alkaline earth metal such as Mg. The resin B is preferably a resin having a mol.wt. distribution divided into two or more components including a low mol.wt. component whose peak is 1X10<3>-2X10<4> and a high mol.wt. component whose peak is 1X10<5>-2X10<6>. A copolymer contg. a styrene monomer and a (meth)acrylic ester monomer as constituents may be used as the resin C.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a developer used for developing electrostatic latent images formed in electrophotography, electrostatic printing, electrostatic recording, etc. The invention relates to a two-component electrostatic latent image developer (hereinafter simply referred to as developer) consisting of toner particles and carrier particles, which is particularly preferably used for hot roller fixing.

[Background of the invention]

In electrophotography, an electrostatic latent image is usually formed by charging and exposing an electrostatic image carrier made of a photoconductive photoreceptor, and then this electrostatic latent image is placed in a binder made of resin with a coloring agent, etc. The resulting toner image is transferred to a support such as transfer paper and fixed to form a visible image.

In order to obtain a visible image as described above, it is necessary to fix the toner image, and conventionally, a heat roller fixing method that has high thermal efficiency and can perform high-speed fixing has been widely adopted.

However, in recent years, efforts have been made to (a) suppress overheating deterioration of copying machines, (b) prevent thermal deterioration of photoreceptors, and (
C) To shorten the warm-up time required for the heat roller to rise to a temperature that can be fixed after the fuser is activated, and (d) To reduce the temperature drop in the heat roller due to heat being absorbed by the transfer paper. In response to demands such as making it smaller to enable continuous copying multiple times and (e) increasing thermal safety, we reduced the power consumption of the fuser heater and lowered the temperature of the heat roller. There is a strong demand to be able to perform a fixing process in the same state.

Therefore, the toner is also required to be able to be fixed well at low temperatures.

Furthermore, toners can exist stably as a powder without agglomerating under the environmental conditions of use or storage;
In other words, it is necessary to have excellent blocking resistance.
Furthermore, in the heat roller fixing method, which is preferred as a fixing method, an offset phenomenon occurs, that is, a part of the toner forming the image is transferred to the surface of the heat roller during fixing, and this is transferred again to the transfer paper that is sent next, forming the image. Since the phenomenon of staining is likely to occur, it is necessary to provide the toner with the ability to prevent the occurrence of the offset phenomenon, that is, offset resistance.

The developer is a two-component developer in which the toner contains a magnetic substance to give it magnetism and eliminates the need for a carrier, and a two-component developer consisting of a non-magnetic toner or a slightly magnetic toner and a magnetic carrier. There are component developers,
The latter two-component developer is widely used because it is easy to control triboelectrification of the toner, has excellent developability, good image quality, and can impart any color to the toner. As such a two-component developer, a developer consisting of an iron powder carrier and a toner is conventionally known, but in a developer using this iron powder carrier, the triboelectric charging property of the toner is unstable and the yield is low. This has the disadvantage that fog occurs in the displayed image.

That is, upon friction with the toner, the surface rear triboelectrification of the iron powder carrier particles becomes even more unstable, resulting in a decrease in image density and an increase in fog. Therefore, if images are continuously formed in an electrophotographic apparatus using a developer using an iron powder carrier, the developability deteriorates after a few times, making it impossible to maintain good image quality.

This phenomenon becomes more pronounced when the environmental conditions become hot and humid.

Furthermore, if the toner is a developer that can be fixed at low temperatures, it will film on the carrier, resulting in defects in durability and image quality under high temperature and high humidity conditions.

Although various studies have been made in the past to solve the above-mentioned drawbacks, the current situation is that it is not possible to obtain a satisfactory solution for all of them.

For example, there is a proposal that the resin used to improve offset resistance is composed of a low molecular weight polymer component and a high molecular weight polymer component (JP-A-56-158340, JP-A-56-158340;
-16144 and No. 58-202455, etc.), this is convenient for introducing high molecular weight polymer components into the toner, but at the same time, the fixing temperature becomes higher, making it difficult to fix at lower temperatures. On the other hand, if the glass transition point or softening point of the resin is lowered to enable the low-temperature fixing properties of 1-ner, not only will the offset resistance deteriorate, but also the blocking resistance will decrease. However, there are drawbacks such as a decrease in durability due to toner filming on the carrier particles and the occurrence of filming on the carrier particles and the surface of the photoreceptor under high temperature and high humidity conditions.

Also, for example, JP-A No. 57-178250, JP-A No. 61-1
No. 10155 and No. 61-110156 attempt to expand the offset resistance, blocking resistance, and allowable fixing temperature range using a resin obtained by reacting a polymer having a carboxyl group with a metal compound. The one-component developer disclosed in the publication or the two-component developer using an iron powder carrier has unstable triboelectric charging properties under high temperature and high humidity conditions, tends to film on carrier particles and the surface of the photoreceptor, and is difficult to clean with a cleaning blade. Cleaning failure occurs due to fusion to the surface, and as a result, good images cannot be obtained continuously and durability deteriorates.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a developer which solves heavy engineering problems, has good anti-offset properties, and can be fixed at a lower temperature.

Another object of the present invention is to provide a developer with good blocking resistance.

Another object of the present invention is to have stable triboelectric charging properties,
It is an object of the present invention to provide a developer having good durability and capable of stably producing good images.

A further object of the present invention is to provide moisture resistance and durability that will not cause filming on carrier particles, the surface of the photoreceptor, the cleaning blade, etc. even under high temperature and high humidity environmental conditions, and will allow stable images to be obtained even after multiple uses. The object of the present invention is to provide a developer with good properties.

[Structure of the invention]

The object of the present invention described above is to provide toner particles (A) whose main component is a resin obtained by reacting a carboxyl group present in a polymer component with a polyvalent metal compound, and a magnetic material whose surface is coated with a resin. This is achieved by an electrostatic latent image developer containing resin-coated carrier particles (B).

According to the developer having such a structure, the resin, which is the main component of the toner, has a crosslinked structure due to ionic bonding between the carboxyl group and the metal atom in the polymer component, but compared to a crosslinked structure due to coexisting bonds. and are much more loosely connected. Therefore, even if the content of the low molecular weight polymer component in the resin is increased, the offset and blocking resistance will not deteriorate due to crosslinking by ionic bonds, and since it is based on gentle ionic bonds, it is different from crosslinking by covalent bonds. The properties of the low molecular weight polymer component are reflected, and the fixing properties are also improved. Furthermore, by containing an ionic crosslinked structure and a high molecular weight polymer component, it becomes a tough resin, suppressing the filming property where a part of the toner component is transferred due to collision with carrier particles or the surface of the photoreceptor, and improving durability. improves.

1Jnlf? +<1:l-2;jL-h-/7'lA・
・-2-Part; I) I! It is not possible to satisfy all of the characteristics under the r, J'i'-EL conditions, and satisfactory performance is achieved only when combined with a certain specific carrier.

For such specific carrier particles, resin-coated carrier particles in which the surface of the magnetic material is coated with resin are suitable.

Generally, under high temperature and high humidity conditions, toner tends to film onto carrier particles, the surface of the photoreceptor, and the cleaning blade, but by using the above toner, filming onto the surface of the photoreceptor and the cleaning blade is suppressed. However, when carrier particles and toner collide with each other with a strong impact, if there are irregularities on the surface of the carrier particles, part of the toner ends up filming on the carrier particles. Such a phenomenon is remarkable in carriers such as iron powder that have a highly uneven surface. In order to solve this phenomenon, the surface of the magnetic material is coated with resin to make it hydrophobic and smooth, which suppresses toner filming under high temperature and high humidity conditions, stabilizes triboelectric charging properties, and Durability is improved and good images can be obtained for a long period of time.

As the resin contained in the toner constituting the developer of the present invention, a resin obtained by reacting a carboxyl group present in a polymer component with a polyvalent metal compound is used.

The resin contained in the toner has a molecular weight distribution divided into at least two groups, a low molecular weight polymer component and a high molecular weight polymer component, and has a molecular weight distribution measured by gel permeation chromatography (GPC). In the distribution curve, the maximum value on the low molecular weight polymer component side is LX 1
0'~2X 10', polymer (1111txto5~
It is preferable to have at least two maximum values of 2×1G”. By designing in this way, fixing can be performed at a lower temperature, and the elastic modulus at the time of melting can be increased, thereby further improving offset resistance. At the same time, it can also have good blocking resistance.Furthermore, the high molecular weight polymer component can make the resin tough, suppressing the generation of fine powder due to collisions with carriers and photoreceptors. This prevents contamination of the carrier and photoreceptor surface.

When introducing a carboxy group for reacting with a polyvalent metal compound to form an ionic bond, it is sufficient that the carboxy group is introduced at least into the low molecular weight polymer component.

Fine powder generated from toner components due to collisions with carrier particles and the surface of the photoreceptor is mainly caused by relatively brittle components with low molecular weights. By doing so, it is possible to suppress the generation of fine powder, which is a cause of filming.

The monomer for obtaining the polymer of the main component resin of the toner is a polymer containing at least one selected from styrene monomers, acrylic acids such as methacrylic acid, and ester monomers as an essential component. Preferably, it is a combination. Furthermore, in order to obtain a polymer having a carboxyl group, a monomer selected from acrylic acid (including methacrylic acid, etc.) and its derivatives may be copolymerized in addition to the above monomers. A preferable monomer having a carboxy group to be copolymerized is a half-ester compound having a structure obtained by an esterification reaction between an acrylic ester, a methacrylic ester, or a derivative thereof having a hydroxyl group and a dicarboxylic acid compound.

If the carboxy group is introduced at a position that has little effect on the main chain structure as described above, the steric hindrance of the chemical structure will be reduced and the reaction with the polyvalent metal compound will proceed efficiently, achieving the objective of the present invention. It is possible to generate effective ionic bonds to achieve a good crosslinked structure.

Examples of the styrene monomer include styrene, 0-
Methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-ethylstyrene, 2.
3-dimethylstyrene, 2,4-dimethylstyrene, p
-n-butylstyrene, p-tert-butylstyrene, p-n-hexylstyrene, p-n-octylstyrene, ';' n-nonylstyrene, p-n-decylstyrene, pn-dodecylstyrene, p- Methoxystyrene, p-phenylstyrene, p--h S Ii
+7:t, 1. ~ Nori I:
3h l-l+1. F: f-l, ・ノス-et, etc. can be mentioned. Among these, styrene is particularly preferred.

It is necessary for the resin for I/ner to have appropriate crushability during toner production, and if the content of the styrene component in the copolymer is below 30 years, the crushability tends to decrease. Usually 30% or more, preferably 40% by weight
The upper limit is generally preferably 95 g x amount %.

Examples of the acrylic ester and methacrylic ester include methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, lauryl acrylate, and acrylic acid. Acrylic acid esters such as 2-ethylhexyl, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, and methyl α-chloroacrylate; methyl methacrylate;
Ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isoie methacrylate +1. J, -Chishi/FIII1. M--J-/? ,:LIl,J1
1) Dodecyl 11++1 acid, lauryl methacrylate,
Examples include methacrylic acid esters such as 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, and diethylaminoethyl methacrylate.

Examples of the carboxy group-containing compound forming the half-ester compound include aliphatic dicarboxylic acid compounds such as malonic acid, succinic acid, and glutaric acid, and aromatic dicarboxylic acid compounds such as phthalic acid; A half-ester compound can be obtained by an esterification reaction with a derivative of methacrylic acid.

The dicarboxylic acid compound may have a hydrogen atom substituted with a halogen group element, a lower alkyl group, an alkoxy group, or the like, or may be an acid anhydride.

The hydroxyl group-containing acrylic acid or methacrylic acid derivative may be one in which 1 or 2 moles or more of an alkylene oxide such as ethylene oxide or propylene oxide is added to acrylic acid or methacrylic acid, or acrylic acid or methacrylic acid. It may also be a hydroxyalkyl ester obtained by subjecting a dihydric alcohol such as propylene glycol to an esterification reaction.

The preferred half-ester compound has the following general formula % Formula % However, in the general formula, 2 represents a divalent bonding group having 3 or more carbon atoms and having an ester bond in the molecular chain, and has a substituent. Good too. RI represents a hydrogen atom or a methyl group.

More preferable compounds are represented by the following formulas (1) to (4).

However, in the formula, R,, R, represents a hydrogen atom or a methyl group, m represents 1-14, and n represents 0-8.

However, in the formula, R4 and Rs are H or C)13. h is 1~
represents an integer of 14, X is a hydrogen atom, a halogen group element,
Represents a lower alkyl group or an alkoxy group.

However, in the formula, R8 is H or CH! l and j represent integers from 3 to 6, and k represents an integer from 0 to 8.

However, in the formula, R7 represents H or CI+3.12 represents an integer of 3 to 6, and Y represents H, a halogen group element, a lower alkyl group, or an alkoxy group.

Among the half-ester compounds represented by formulas (1) to (4), those represented by formula (1) are preferred.

Examples of the half-ester compound represented by the formula (1) include succinic acid mono(meth)acryloyloxyethyl ester, succinic acid mono(meth)acryloyloxypropyl ester, glutaric acid mono(meth)acryloyloxyethyl ester, and phthalic acid. Examples include mono(meth)acryloyloxyethyl ester and mono(meth)acryloyloxypropyl phthalate ester.

The styrene monomer, the acrylic acid ester monomer,
A polymer obtained from a methacrylic acid ester monomer and a half-ester compound obtained by an esterification reaction between an acrylic acid or methacrylic acid derivative having a hydroxyl group and a dicarboxylic acid compound has a monomer unit content of , the styrenic monomer is 30 to 95% by weight
, preferably 40 to 95% by weight, 70 to 5% by weight, preferably 5 to 50% by weight of the acrylic ester monomer or methacrylic ester monomer, and 0.5% by weight of the half ester compound. It is desirable that the amount is 5 to 30% by weight, preferably 1 to 20% by weight.

The number of blind counterfeits of the acrylic ester monomer or methacrylic ester monolayer is more than 70%,
Or the content of the half ester compound is 0.5% by weight
If the amount is less than 1, offset resistance during high-temperature fixing may deteriorate, and blocking resistance and plasticizer resistance may also deteriorate.

The resin contained in the toner of the present invention is a resin obtained by reacting the above-mentioned carboxyl group-containing polymer with a polyvalent metal compound.

The metal elements in the polyvalent metal compound include Cu,
Ag, Be, Mg, Ca, Sr, Ba,
Zn, Cd, A12. Ti.

Ge, Sn, V, Cr, Mo, Mn, F
e, Ni, Co, lr, Se.

Examples include.

Among these various elements, alkaline earth metals, (Be
, Mg, Ca, Sr, Ba) and zinc group elements (Zn, Cd) are preferred, with Mg and Zn being particularly preferred.

These polyvalent metal compounds include, for example, fluorides, chlorides, chlorates, bromides, iodides, oxides, hydroxides, sulfides, sulfites, sulfates, selenides,
Examples include lower alkyl metal compounds such as tellurides, nitrides, nitrates, phosphides, phosphinates, phosphates, carbonates, orthosilicates, acetates, oxalates, methylates, and ethylates.

Among these, acetates and oxides are preferred.

The amount of the polyvalent metal compound to be added varies depending on the type and amount of monomers constituting the polymer, and cannot be definitively stated, but for example, if the polymer contains the styrene monomer,
When a low molecular weight polymer component and a high molecular weight polymer component are constituted by the (meth)acrylic acid ester monomer and the half ester compound, the amount is 0.1 to 1 mole per mole of the half ester compound charged. 1 mole is sufficient.

To react this polyvalent metal compound and the polymer,
For example, a solution containing the polymer obtained by polymerization using a solution polymerization method is mixed with a solution in which the metal compound or heavy industrial compound is dispersed, the temperature is raised, and the solvent is removed over about 1 to 3 hours. It is preferable to complete the reaction by maintaining the temperature in the system at about 150 to 180° C. for one hour or more.

In some cases, 1 g of the metal compound may be present in the reaction system together with the solvent before starting the polymerization, and the polymer obtained by removing the solvent and the polyvalent metal compound may be mixed in a roll mill, kneader, or extruder. Melt kneading may also be performed using, for example.

The resin obtained by reacting the polymer and the polyvalent metal compound thus obtained has an ionic bond between the carboxy group contained in the polymer component and the metal atom, and this ionic bond forms a kind of crosslinked structure. It is appearing. This ionic bond is much looser than covalent bonds.

In the polymer molecular weight distribution of the toner main component resin, if the maximum value of the molecular weight distribution of one low molecular weight polymer component is smaller than the above range, blocking resistance may deteriorate, and if it is larger than the above range, fixing Sexuality may decrease. Furthermore, if the maximum value of the molecular distribution of the high molecular weight polymer component is smaller than the above range, offset resistance, durability, and high temperature/humidity resistance may deteriorate; if it is larger than the above range, fixing properties may deteriorate. There are things to do.

7IA l-lΔヱ帛MutaiHaNavy^^1-Bone Shi1-/MinomuヱNephew The molecular weight distribution of a polymer consisting of a polymer component and a high molecular weight polymer component is given by the weight average molecule in (M w)
/l! l! r average molecule ffi (M n) (hereinafter Mw/
Mn) value is 3.5 or more, preferably 4.0
-40 is desirable.

The resin having a bimodal molecular weight distribution in a low molecular weight portion and a high molecular weight portion preferably has a content of a high molecular weight polymer component of 15% or more, particularly 15 to 50%, based on the entire resin. . If the content of the high molecular weight polymer component is less than 15%, offset resistance and durability may deteriorate.

The resin in the present invention may be produced by any method as long as it has a bimodal molecular weight distribution such as Moe's. For example, a first stage polymerization is performed in which either a high molecular weight polymer component or a low molecular weight polymer component is first produced by polymerization, and then one of the produced polymer components is transferred to the other polymer component. The other polymer component is produced by dissolving it in the monomer that provides the polymer constituting the polymer component and performing a large second stage polymerization, resulting in a polymer having a molecule 1 bimodal distribution. Can be done.

It is presumed that the polymer obtained by the two-stage polymerization is a mixture of a low molecular weight polymer component and a high molecular weight polymer component uniformly at the molecular level.

This two-stage polymerization can be carried out, for example, by a solution polymerization method, a suspension polymerization method, an emulsion polymerization method, etc., and among them, a solution polymerization method is preferable.

On the other hand, a polymer with a bimodal molecular distribution can be obtained by mixing a low molecular weight polymer component and a high molecular weight polymer component, but the bimodal distribution obtained by mixing Since the polymers may not be uniformly mixed at the molecular level, the polymers used in the present invention are particularly preferably those obtained by the two-stage polymerization method.

Furthermore, the toner resin in the present invention has a glass transition point of 50 to 80°C, a glass transition point of its low molecular weight polymer component is 50°C or higher, preferably 55°C or higher, and a high molecular weight polymer component It is desirable that the temperature is 65°C or less, preferably 60°C or less.

This is because blocking resistance can be improved by adjusting the glass transition point. Note that the glass transition point can be easily adjusted by appropriately selecting the type of single body.

Furthermore, the toner resin according to the present invention may contain a monopolymer unit such as vinyl acetate, vinyl propionate, vinyl chloride, or ethylene in its molecular chain as long as the object of the present invention is not impaired. Alternatively, polymers of the above monomers may be blended. Further, polyester resin or epoxy resin may be included.

The toner of the present invention contains a coloring agent in the above-mentioned specific resin, and may further contain a magnetic material and a property improver in the resin, if necessary.

As a coloring agent, carbon black, nigrosine dye (
C, 1, No. 50415B), Aniline Blue (C,
1, No.

50405), Calco Oil Blue (C, 1, No, a
zoic Blue3), chrome yellow (C, 1, N
o, 14090), ultramarine blue (C0I, N
o, 77103), DuPont Oil Red (C, 1, N
o, 26105), quinoline yellow (C, 1, No,
47005), methylene blue chloride (C, [, N
o, 52015), phthalone anine blue (C, 1, N
o, 74160), malachite green oxalate (
C, 1, No. 42000), lamp black (C, 1
, No. 77266), Rose Bengal (C, 1, No.
.

45435), mixtures thereof, and others. These colorants need to be contained in a sufficient proportion to form a visible image of sufficient density, and are usually about 1 to 20 parts by weight per 100 parts by weight of the resin.

The magnetic material may be a metal or alloy that exhibits ferromagnetism such as ferrite, magnetite, iron, cobalt, or nickel, or a compound containing these elements, or a material that does not contain a ferromagnetic element but can be made by subjecting it to appropriate heat treatment. Mention may be made of alloys which become ferromagnetic, such as alloys of the type called Heusler alloys containing manganese and copper, such as manganese-copper-aluminum, manganese-copper-tin, or chromium dioxide, among others. These lectures
Thick + positive ¥: 1 episode? Stem 01-1 micron scale E) Length 1
It is evenly dispersed in the resin. And its content is
The amount is 20 to 70 parts by weight, preferably 40 to 70 parts by weight per 100 parts by weight of toner.

The property improver includes a fixability improver, a charge control agent,
There are others.

Examples of fixability improvers include polyolefins, fatty acid metal salts, fatty acid esters and fatty acid ester waxes, partially saponified fatty acid esters, higher fatty acids, higher alcohols, liquid or solid paraffin wax, polyamide waxes, polyhydric alcohol esters, and silicone. Fes, aliphatic fluorocarbon, etc. can be used. In particular, the softening point (ring and ball method JIS K2531) is 6.
Wax having a temperature of 0 to 150°C is preferred.

As the charge control agent, conventionally known ones can be used, such as nigrosine dyes, metal-containing dyes, and the like.

Further, the toner of the present invention is preferably mixed with inorganic fine particles such as a fluidity improver.

The inorganic fine particles used in the present invention include -
The secondary particle size is 5 μm to 2 μm, preferably 5 μm to 5 μm.
00 mμ particles. Further, the specific surface area measured by the BET method is preferably 20 to 500 m''/g. The proportion mixed into the toner is 0.01 to 5 vt%, preferably 0.01 to 2.0 wt%. Examples of inorganic fine powder include silica fine powder, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide,
Silica sand, clay, mica, diatomaceous earth, chromium oxide, cerium oxide, red iron oxide, antimony trioxide, magnesium oxide,
Examples include zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, silicon nitride, etc.
Particularly preferred is silica fine powder.

The silica fine powder referred to herein is a fine powder having a 5t-0-Si bond, and includes both those manufactured by a dry method and a wet method. In addition to anhydrous silicon dioxide, aluminum silicate, sodium silicate, potassium silicate, magnesium silicate, zinc silicate, etc. may be used;
Those containing 5% by weight or more are preferable.

Specific examples of these fine silica powders include various commercially available silicas, but those having hydrophobic groups on the surface are preferred, such as AEROSIL R-972, R-974゜R-
805, R-812 (manufactured by Aerosil), Taranox 500 (manufactured by Talco), and the like. In addition, silica fine powder treated with a silane coupling agent, a titanium coupling agent, silicone oil, silicone oil having an amine in its side chain, etc. can be used.

To give an example of a preferred method for manufacturing the toner according to the present invention, first, a resin material for the binder or a toner component such as a colorant is added thereto as necessary is melt-kneaded using an extruder, and then cooled. After that, it is finely pulverized using a jet mill or the like, and then classified to obtain a toner having a desired particle size. Alternatively, a toner having a desired particle size can be obtained by melting and kneading the toner using an extruder and then spraying it in a molten state using a spray dryer or dispersing it in a liquid.

The image forming method of the present invention involves preparing a developer using the above-mentioned specific toner, forming and developing a latent image using a commonly used electrophotographic copying machine, and transferring the obtained toner image. A copy image is formed by electrostatically transferring the image onto paper and fixing it by a heating roller fixing device in which the temperature of the upper heating roller is set to a constant temperature.

The toner according to the present invention is particularly preferably used for fixing in which the contact time between the toner on the transfer paper and the heating roller is within 1 second, particularly within 0.5 seconds.

The resin-coated carrier in the developer of the present invention has a spherical and smooth surface because of the resin coating.

For this reason, it is thought that effective frictional charging with the toner is achieved, carrier scattering and toner scattering can be prevented, fogging and carrier adhesion are prevented, and clear images can be obtained. In addition, by using the resin-coated carrier described above, even when making multiple copies under high temperature and humidity conditions, the mold release property is B.
Even if it is subjected to curing pressure, it does not physically adhere strongly to the toner, and toner does not film on the carrier. As a result, there is no fogging, toner scattering, carrier adhesion, etc., and it is durable. It is thought that good and clear images can be obtained.

In particular, the following copolymers used for resin coating of carriers are:
It is obtained by polymerizing a styrene monomer as a hard component and acrylic acid (or methacrylic acid) or its ester, which exhibits tough and flexible functions, so it exhibits the characteristics of both of these monomer components. However, at the same time, its drawbacks can also be eliminated. In other words, the brittleness caused by styrene is eliminated by acrylic (or methacrylic) acid or its ester, and while the flexibility provided by the latter is maintained, appropriate hardness can be imparted by the styrene component. These physical properties improve mold releasability, prevent adhesion with toner, etc., as described above.

The resin used for coating the carrier particles is obtained by polymerizing a styrene monomer and a monomer component containing an acrylic acid or its ester monomer and/or a methacrylic acid or its ester monomer. It is a resin containing a copolymer.

Examples of the styrene monomer include styrene, 〇-methylstyrene, p-methylstyrene, p-methylstyrene,
α-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-n-butylstyrene, p-ter
t-butylstyrene, p-n-hexylstyrene, p-
n-octylstyrene, p-n-nonylstyrene, p-
n-decylstyrene, p-n-dodecylstyrene, ρ-
Examples include methoxystyrene, p-phenylstyrene, p-chlorostyrene, and 3,4-dichlorostyrene, among which styrene is most preferred.

Examples of the acrylic ester and methacrylic ester copolymerized with the styrene monomer include methyl acrylate, ethyl acrylate, n-propyl acrylate, 1so-propyl acrylate, n-butyl acrylate, 1so-butyl acrylate, tert-butyl acrylate, 2-ethylhexyl acrylate,
Cyclohexyl acrylate, n-octyl acrylate, 1so-octyl acrylate, n-dodecyl acrylate, 2-hydroxyethyl acrylate, 2-methoxyethyl acrylate, 2-chloroethyl acrylate, benzyl acrylate, n-methylaminoethyl acrylate, dimethylamino Acrylic esters such as ethyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, 1s
o-propyl methacrylate, n-butyl methacrylate, 1so-butyl methacrylate, tert-butyl methacrylate, 2-ethylhexyl methacrylate,
Examples include methacrylic acid esters such as cyclohexyl methacrylate, n-octyl methacrylate, 1so-octyl methacrylate, n-dodecyl methacrylate, 2-hydroxy methacrylate, benzyl methacrylate, n-methylaminoethyl methacrylate, and dimethylaminoethyl methacrylate. Of these, methyl methacrylate is most preferred.

The above copolymer can be produced by commonly used emulsion polymerization, bulk polymerization,
It can be produced by suspension polymerization or solution polymerization.

In addition, the molecular weight of the heavy engineering copolymer is the weight average molecular weight (M
w) is 10,000 or more, and the number average molecular weight (Mll) is 2QQ (1
As mentioned above, My/Mn is preferably 2.0 or more, the weight average molecular weight is less than 10,000, the number average molecular weight is less than 2000, and My/Mn is preferably less than 2.0.
When M n is less than 2.0, the coating resin is likely to peel off due to brittleness, and durability is likely to be poor.

Furthermore, the glass transition temperature (Tg) of the copolymer is 60°C.
It is preferable that it is above. If the temperature is lower than 60° C., it will be sticky, and toner will easily adhere to it and cause filming.

The average thickness of the coating resin is 0.1 to 10μ, preferably 0.3 to 4μ, more preferably 0.3 to 2.0μ.
It is. If it is less than 0.1μ, the insulation properties are poor and it is difficult to obtain good developability, and if it exceeds 4μ, particularly 10μ, the magnetization of the carrier becomes too small and carrier adhesion tends to occur.

The resin is composed of a styrenic monomer (S t) and an acrylic ester (AE) and/or a methacrylic ester (M
A copolymer containing A E ) as a constituent component is preferred.

The styrene component has the effect of hardening the resin and efficiently triboelectrically charging it, and the acrylic ester and methacrylic ester components have the effect of making the resin tough, and the synergistic effect of both makes the resin hard and strong and durable. It can be used as a carrier with good properties.

For this purpose, the weight composition ratio of the copolymer is preferably St/AE and/or MAE=9/1-1/9.

Another effect is that the charge amount can be adjusted arbitrarily by changing the component ratio.

The magnetic material of the resin-coated carrier in the present invention includes substances that are strongly magnetized in the direction of a magnetic field, such as ferrite, magnetite, iron, nickel,
Metals that exhibit ferromagnetism such as cobalt, or alloys or compounds containing these metals, or metals that do not contain ferromagnetic elements but can exhibit strong Wi properties through appropriate heat treatment, such as gold, manganese, copper, and aluminum. Alternatively, an alloy called Heusler alloy such as manganese-copper-tin or chromium dioxide can be used.

Ferrite is a general term for magnetic oxides containing iron, and is MO・Fe20 (M is a divalent metal).
Ferrites, which are not limited to spinel-type ferrites represented by the chemical formula, are particularly preferable for obtaining a carrier suitable for the purpose of the present invention because various magnetic properties can be obtained by changing the composition of the metal components contained in ferrites. In addition, since ferrite is an oxide, its specific gravity is smaller and lighter than metal powders such as iron powder and nickel powder, so it is difficult to mix with toner.
This facilitates stirring and is suitable for achieving uniform toner concentration and Ti band amount. Furthermore, since ferrite has a higher electrical resistance than iron powder, nickel powder, cobalt powder, etc. (10s to 10'2 Ωcm), even if the resin insulating layer on the surface is a thin film of about 0.5μ, it cannot be developed. This has the advantage that it is possible to realize an insulating carrier that can be used satisfactorily in a developing method in which a high bias electric field is applied to the gap.

The ferrite has a saturation magnetization of 10 to 40 emu/g and a coercive force of 0.1 to t under an external magnetic field of 10,000 e.
o.

Oe is preferable, and the resistivity is 1 x 108~
Preferably, it has a specific gravity of 1×10′1 Ωcm, a specific gravity of 4.0 to 5.5, and a porosity of 1.0 to 10%.

The method for manufacturing the resin-coated carrier used in the present invention involves dissolving the coating resin and other resin components added as necessary in an organic solvent to prepare a coating liquid, and applying a coating layer to the carrier surface by, for example, spray drying. can be formed. Alternatively, the magnetic particles of the carrier are raised to an equilibrium height by a rising pressurized gas flow, for example in a actuated bed apparatus, and then the coating liquid is spray applied by the time the magnetic particles fall again. . This application can be repeated to form a coating layer.

In the present invention, in order to obtain a more preferable image, the toner particle size (weight average) is less than 20 μm, especially 15 to 1 μm.
The range is preferably m.

When the thickness exceeds 15 μm, high resolution and excellent gradation reproducibility cannot be obtained, but especially when the thickness exceeds 20 μm, the resolution of fine characters decreases. If the toner is less than 1 μm, fogging and toner scattering occur, making it impossible to obtain clear images.

In order to improve resolution and gradation reproducibility, the resin-coated carrier in the present invention is preferably spherical and has a weight average particle diameter of 200 μm or less, particularly preferably 5 μm or more and 100 μm or less. Here, the carrier particle diameter is 100μ
In particular, if the thickness exceeds 200μ, the developability will deteriorate and the image quality will deteriorate. If it is less than 5 μm, the developability, triboelectric chargeability, fluidity, etc. of the developer will be poor, and carrier scattering will likely occur.

In addition, in order to prevent charges from being injected by the bias voltage and causing carriers to adhere to the photoreceptor surface and to prevent charges forming a latent image from disappearing, the resistance of the carrier is set to 10IlΩC.
It is preferable to use an insulating material having an insulating value of at least 10 ΩcTn, preferably 10 11 Ωcm or more, and more preferably 10' (ΩcTn or more).

In addition, the particle size or average particle size of toner and carrier in the present invention means the weight average particle size, and the toner σ) heavy weight tflN is a value measured with a Coulter counter (manufactured by Coulter Co., Ltd.). The weight average particle size of the carrier particles is a value determined by actually measuring the particle size of each particle using a microscope.

In addition, the specific resistance (resistivity) of the particles is 0.500
After placing the packed particles in a container with a cross-sectional area of 1 m" and tapping, a load of 1 kg/am2 was applied to the packed particles to a thickness of about 1 crane, and 102 cm was placed between the load and the bottom electrode.
It is determined from the current value that flows when an electric field of ~10'V/c... is generated.

The above-mentioned mixing ratio of toner and carrier is appropriately set such that the toner concentration (weight ratio of toner to developer) is 1 to 40 wt%, preferably 1.5 to 25 wt%.

In this specification, the softening point refers to Koka type flow desta rC
FT-500 model (Shimadzu Corporation), the measurement conditions were a load of 20 kg/am2, a nozzle diameter of 1 mm, a nozzle length of 1 mm, preheating at 80°C for 10 minutes, and a heating rate of 6°C/min. , sample jt1cm' (intrinsic specific gravity x 1c
...When measured and recorded as weight expressed as
The temperature at 2.

In addition, the glass transition point is the differential scanning calorimeter 1 low temperature DSCJ
(manufactured by Rigaku Denki Co., Ltd.) at a temperature increase rate of 10°C/min. The glass transition point is defined as the temperature at the intersection with the tangent line showing the maximum slope between

Number average molecular weight Mn and weight average molecular Ji in the polymer
The value of M w can be measured by various methods, and there is some variation depending on the measurement method.

In Suimei A, Mn and Mw are defined as values obtained by the following measurement method.

That is, the weight average molecular weight Mw and number average molecule Ji M n are measured by gel permeation chromatography (GPC) under the conditions described below.

At a temperature of 40°C, the solvent (tetrahydrofuran) was flowed at a flow rate of 1.2 ml per minute, and the concentration was 0.2 g/ZoW, e
The sample weight of the tetrahydrofuran sample solution is 3 mg.
Inject and measure. When measuring the molecular weight of a sample, select measurement conditions in which the molecular weight of the sample falls within a range in which the logarithm of the molecular weight and the count number of a calibration curve created using several types of monodispersed polystyrene standard samples form a straight line.

The reliability of the measurement results is determined by the N
B S 706 boristyrene standard sample has weight average molecular weight jl M W = 28.8X 10' number average molecular weight
This can be confirmed by M n = 13.7X 10'.

Moreover, any column may be used as the GPC column as long as it satisfies the above conditions. Specifically, for example, TSK-GEL, CMHe (manufactured by Toyo Soda Co., Ltd.), etc. can be used.

〔Example〕

Next, examples of implementation of the present invention will be specifically explained.

(Synthesis of resin) Synthesis example-! A thermometer, a stirrer, a nitrogen gas inlet tube, and a flow-down condenser were placed in a M3 (2 separable flask) equipped with 5 toluene.
After introducing nitrogen gas from the gas inlet pipe to create an inert atmosphere inside, it was heated in an oil bath to the reflux temperature of toluene. Then 210 g of styrene, n-
Butyl acrylate 60g 1 Methyl methacrylate 30
A solution consisting of 0.9 g of g1 benzoyl peroxide was placed in a flask and reacted at reflux temperature for 14 hours to obtain a high molecular weight polymer.

Next, a polymerization reaction was carried out while dropping a solution of 487 g of styrene, 35 g of α-methylstyrene, 5 g of n-butyl acrylate 1Q, 73 g of monoacryloyl oxine ethyl succinate, and 42 g of benzoyl peroxide into the flask containing the high molecular weight polymer solution. Ta. After dropping the solution, a polymerization reaction was further carried out for 4 hours to obtain a low molecular weight polymer.

Next, 8 g of zinc oxide was added into the flask containing the solution consisting of the high molecular weight polymer and the low molecular weight polymer.

After the reaction was completed, the toluene solvent was removed under reduced pressure, and the carboxy group and the metal compound were reacted to obtain resin A of the present invention.

The molecular weight distribution of this resin A was measured using gel permeation chromatography (LC-802U R, GM [-1, column, manufactured by Toyo Soda Co., Ltd.) and found to be 7.5 x 103. It was a bimodal distribution with maximum values at and 2.8x 105. Moreover, the weight average molecular weight (Mw) was 12,000,000 Mw/Mn was 17.1.

Synthesis Example-2 High molecular weight polymer components: 180 g of styrene, 30 g of n-butyl acrylate, n-butyl methacrylate)
60 g, methyl methacrylate 30 g, azobisisobutyronitrile i, s,, as low molecular weight polymer components styrene 372 g, α-methylstyrene 70 g,
Resin B was obtained using 70 g of n-butyl acrylate, 70 g of n-butyl methacrylate, 70 g of methyl methacrylate, and 48 g of monoacryloyloxyethyl isophthalate in the same manner as in Metallization-1.

This resin B has maximum values of molecular weight distribution at 1.2X 10' and 2.4X 10', Mw 115,000, M
w/M n = 9.5.

Synthesis Example-3 Styrene 150% as a high molecular weight polymer component. ．． 520 g of styrene, 40 g of α-methylstyrene, 120 g of 2-ethylhexyl acrylate, 80 g of monoacryloylpropyl succinate, and benzoyl peroxide as low molecular weight polymer components. 40g oxide
Resin C was obtained in the same manner as in Synthesis Example 1 except that 13 g of magnesium oxide was used as the metal compound.

The maximum value in the molecular weight distribution of resin-C is 9.2X 10
' and 3.9X 105, and the weight average molecular weight (M
w) is toz, ooo, M w/ M n is 12.5
Met.

Synthesis Example-4 High molecular weight polymer components: 195 g of styrene, 175 g of n-butyl methacrylate, 1-4 methyl methacrylate
0 g, 2.0 g of ben-1 silyl peroxide, 215 g of styrene as a low molecular weight polymer component, 70 g of α-methyl° styrene, 210 g of n-butyl methacrylate,
Methyl methacrylate-1-70g, monoacryloylprobyl isophthalate-40g, benzoyl peroxide 3
A resin resin was obtained in the same manner as in Synthesis Example 1, except that 6 g of zinc acetate was used as the metal compound and 20 g of zinc acetate was used.

The maximum value of molecular weight in the molecular weight distribution of resin is 3.8
They were X 103 and 1.8X 10'. Also, Mw is 9
6,000, Mw/Mn was 13.7.

Synthesis Example-5 High molecular weight polymer components: 130 g of styrene, 50 g of 2-ethylhexyl acrylate, 1 methyl methacrylate
・20g, 0.4g of benzoyl peroxide, 520g of styrene, 40g of α-methylstyrene, 120g of 2-ethylhexyl acrylate as a polymer component with low molecules
g, methyl methacrylate 80g, monoacryloyl ethyl succinate 40g, benzoyl peroxide 4
Resin E was obtained in the same manner as in Synthesis Example 1 except that 0 g of zinc oxide was used as the metal compound and 4.0 g of zinc oxide was used as the metal compound. tM fat-E
The maximum value of molecular weight in the molecular weight distribution is 8.5X 10
3 and 4.6x 10', and M- is 134,00
0, Mw/Mn was 16.3.

Synthesis Example-6 High molecular weight polymer components: 180 g of styrene, n-butyl acrylate eog, 30 g of methyl methacrylate,
0.9 g of benzoyl peroxide, 30 g of monoacryloyl ethyl succinate, and 487 g of styrene, 35 g of α-methylstyrene, n-
Butyl acrylate 105g, monoacryloyl ethyl succinate 1-73g, benzoyl peroxide 35g
Resin F was obtained in the same manner as in Synthesis Example 1, except that 7.3 g of zinc oxide was used as the metal compound.

The maximum molecular weight of resin-F is 6.4×10 and 3.3
X 10', and Mw is 126,000, M
n was 20.1.

(Synthesis of comparative resin) Comparative synthesis example-1 In addition to the synthesis example-1, in which 8 g of zinc oxide was removed, the maximum values of resin G were at 7.1X to' and 2.8X 10',
Mw was 118,000 and My/Mn was 18.1.

Comparative Synthesis Example-2 400 g of toluene was placed in a 2e separable flask, and after replacing the air with nitrogen gas, the system was heated to the boiling point of toluene, and while stirring, 750 g of styrene, 200 g of n-butyl acrylate, and amber were added. Solution polymerization was carried out by dropping a mixture of 50 g of acid monoacryloyloxyethyl ester and 10 g of benzoyl peroxide as a polymerization initiator dropwise over 2.5 hours.

After the dropwise addition of the mixture was completed, the mixture was further aged for 1 hour while stirring at the boiling point temperature of toluene, and zinc oxide t4. I added ig.

Next, while gradually increasing the temperature of the system to 180°C, toluene was removed from the solvent under reduced pressure, and the styrene-acrylic acid-
Tree II, which is a reaction polymer of 〇-butyl-succinic acid monoacryloyloxyethyl ester copolymer and monolead oxide
I got H.

Comparative Synthesis Example-3 90 g of xylene was placed in a separable flask, and further 75 g of styrene, 20 g of butyl acrylate, 5 g of monobutyl maleate, and 0.5 g of divinylbenzene were added, and after replacing the gas phase with nitrogen gas, the temperature was maintained at 80°C. A solution of 1.2 g of benzoyl peroxide in 10 g of xylene was added, and stirring was continued for 10 hours. Thereafter, the temperature was raised to 95°C and maintained for 3 hours to complete polymerization.

After cooling, the polymerization solution was poured into a large amount of methanol, the precipitate was filtered off, and thoroughly dried at 50°C. Resin I obtained here has M w / M n of 27 and My of 233,000.
Met.

(Preparation of toner) 100 parts by weight of each of the resins A to F obtained in Synthesis Example-1 to Synthesis Example-6, carbon black ([Mogul LJ
, manufactured by Cabot Corporation), 2 parts by weight of polypropylene (Viscol 660P, manufactured by Sanyo Chemical Industries, Ltd.), and 2 parts by weight of Wax-E (manufactured by Hoechst Corporation) were mixed in a Henschel mixer, and then 2 parts by weight of After sufficiently melting and kneading with a roll at a temperature of 130°C, it was cooled and coarsely pulverized, then pulverized with a jet mill and classified, with an average particle size of 11.0 μm.
Toners 1 to 6 according to the present invention were obtained.

(Preparation of Comparative Toner) Comparative Toner (1) Comparative Toner (1) was prepared in the same manner as Toner 1 except that a mixture of 100 parts by weight of resin and 0 parts by weight of carbon black (Mogul LJ, manufactured by Cabot Corporation) was used. Obtained.

Comparison toner (2) 100 parts by weight of resin H and 5 parts by weight of carbon black (Diablack SH: manufactured by Mitsubishi Kasei Corporation) were melt-kneaded, cooled, coarsely pulverized, and further finely pulverized with a jet mill to give a powder of about 13 to 15% by weight.
A comparative toner (2) having an average particle size of microns was prepared.

Comparative toner (3) 1100 parts by weight of resin, 5 parts by weight of zinc salt of di-t-butylsalicylic acid, 8 parts by weight of carbon black, metal salt dye (
Product name: Sabon First Black B.

4 parts by weight of C.1, Acod Black (manufactured by BASF) were sufficiently melted and kneaded in a small pressure kneader. After cooling,
Finely pulverize, select particles of approximately 5 to 20μ, and add toner for comparison (3
).

(Preparation of resin-coated carrier) Carrier a: Monomer composition ratio of styrene and methyl methacrylate is 4
0:60 styrene-methyl methacrylate copolymer (
My: 82,000, Mn: 25,000, Tg
: 105°C) was dissolved in 300 mg of methyl ethyl ketone to prepare a coating solution, and copper-zinc ferrite particles were coated with this coating solution using a spira coater (manufactured by Kaida Seiko Co., Ltd.) to form a coating layer with a film thickness of 1.0 μm. Manufactured carrier.

This will be referred to as "carrier a." The average particle size of this carrier a is 100 μ, the magnetization is 28 emu/gs, and the specific resistance is 10
It was 1'Ωcm or more.

Carrier b: Instead of the copolymer used to prepare the coating liquid in carrier a, a styrene-methyl methacrylate copolymer with a monomer composition ratio of styrene and methyl methacrylate of 60:40 (Mw 73,000 , A carrier having an average coating layer thickness of 0.8 μl was manufactured in the same manner as rear a.This is referred to as "carrier b".The average particle size of this carrier was 100 μl, and the magnetization was 30 emu/g and the specific resistance was 10. “It was more than Ωcm.

Carrier C: Instead of the copolymer used for carrier a, styrene and n
- Styrene-n-butyl acrylate copolymer with a monomer composition ratio of 90:10 to butyl acrylate (Mw:
93,000, Mn: 37,000, Tg near 6℃)
``Carrier C'' in the same manner as Carrier a except that ``Carrier C
” was manufactured. Average particle size is 100μ, magnetization is 26emu
/g.

Comparative carrier (a): The copper-zinc ferrite particles used in carrier a without a resin coating layer were referred to as "comparative carrier (a)".
”.

Comparative carrier (b): E F V 250/400 (manufactured by Nippon Iron Powder Co., Ltd.), which is iron powder particles, was used as comparative carrier b.

Example 1 After mixing 149.75 parts by weight of toner and 0.25 parts by weight of hydrophobic silica (Aerosil R-972, manufactured by Aerosil Co., Ltd.), the mixture was further mixed with 950 parts by weight of carrier a. Thus, developer-1 of the present invention was obtained.

Using the above developer-1, an electrophotographic copying machine [U-B 1
x5000J (manufactured by Konishiroku Photo Industry Co., Ltd.) to form and develop an electrostatic image, and conduct a photocopying test in which the resulting toner image was transferred onto transfer paper and fixed by a heated roller fixing device to form a copy image. The minimum fixing temperature (minimum temperature of the heating roller that allows fixing) and offset occurrence temperature (minimum temperature at which offset phenomenon occurs) are determined by the following method.
was measured.

Minimum fixing temperature: After creating an unfixed image with the above copying machine, a heat roller with a diameter of 50φ whose surface layer is made of Teflon (polytetrafluoroethylene manufactured by DuPont) and a heated roller whose surface layer is made of silicone rubber rK E-1300RT V J (manufactured by Shin-Etsu Chemical Co., Ltd.) by a fixing device consisting of a pressure roller and
A toner image of the sample toner was transferred onto a 64 g/m" transfer paper at a linear speed of 200 mm/sec and a linear pressure of 0.8 kg/
cm, with a nip width of 8 mm, the set temperature of the heat roller is increased stepwise by 5 degrees Celsius within the range of 100 to 240 degrees Celsius, and the fixed image is repeatedly fixed at each temperature. The lowest set temperature for a fixed image exhibiting sufficient abrasion resistance was defined as the lowest fixing temperature.

Note that the fixing device used here does not have a silicone oil supply mechanism.

Offset generation temperature: The measurement of the offset generation temperature is based on the measurement of the minimum fixing temperature, but after creating an unfixed image with the above-mentioned copying machine, the toner image is transferred and fixed using the above-mentioned fixing device. Next, the operation of sending a blank transfer paper to the fixing device under the same conditions and visually observing whether or not toner stains occur thereon is repeated while the set temperature of the heat roller of the fixing device is successively increased; The lowest set temperature at which toner staining occurred was defined as the offset generation temperature.

Furthermore, the blocking resistance of the above toner was measured as follows.

Blocking resistance: Blocking resistance test 1 requires temperature of 55°C and relative humidity of 6.
The sample was left under 0% environmental conditions for 1 day and examined to see if agglomerates were formed.

Next, using the above developer, use the developer at room temperature and humidity (20℃, 60% R
A copying test was conducted on 100,000 sheets under the environmental conditions of high temperature and high humidity (30° C., 80% RH), and the following evaluations were made.

Image quality: The sharpness of the copied image was examined at the beginning and end of the 100,000-time development process.

Filming resistance: Filming resistance is determined by observing the surface of the carrier, the surface of the photoreceptor, and the cleaning blade using an electron microscope or visually at the beginning and end of the 100,000-time development process to check for any deposits. Ta.

The results are shown in Table 1. In the table, regarding image quality, "good" indicates that the image is clear.

Fog: Indicated by relative density with respect to the developed image of a white background portion with an original density of 0.0 (white background reflection density is taken as 0.0).

0 Less than 0.01 △ 0.01 to less than 0.03 did.

The results are shown in Table 1.

Examples 2 to 6 Toners 2 to 6 and hydrophobic silica were mixed in the same manner as in Example 1, and then mixed with carrier to obtain developers 2 to 6. Tests were conducted in the same manner as in Example 1. Ta. The result is below
Shown in the table.

Comparative Example 1 Comparative developer (1) was obtained by mixing parts by weight of 1L tJ-/I) LLJ-Itofu 11mat) qQ.

Using this comparative developer (1), a test was conducted in the same manner as in Example-1. The results are also shown in Table 1.

Comparative Example-2 4 parts by weight of comparative toner (2) and comparative carrier of iron powder (b
) to prepare a comparative developer-(2) by mixing 96 parts by weight,
The test was carried out in the same manner as in Example-1.

The results are also shown in Table 1.

Comparative Example-3 Comparative toner (3) 10 parts by weight, comparative carrier (b) 9
Comparative developer-(3) was prepared by mixing 0 parts by weight, and Example-
A test similar to 1 was conducted. The results are also shown in Table 1.

As shown in Table 1, in the developers 1 to 6 of the present invention,
It has excellent low-temperature fixing properties, anti-offset properties, and anti-blocking properties, and has a wide fixing range.Fog does not occur even under normal temperature and high temperature and high humidity environmental conditions, and cleaning properties are good. It does not adhere to the body surface cleaning blade, has excellent R friction charging properties, and has excellent durability and temperature/humidity resistance, allowing stable and clear images to be obtained over a long period of time.

On the other hand, Comparative Developer (1) has poor low-temperature fixability, and due to brittle low-molecular weight components, it has poor durability due to contamination of the carrier, etc. Especially under high temperature and high humidity conditions, it is difficult to fix. The durability was poor due to the occurrence of . Comparative developer (2) is not only inferior in low-temperature fixing properties but also inferior in durability, and especially under high-temperature conditions, filming occurs, resulting in unstable triboelectric charging properties and poor cleaning. This resulted in poor durability and temperature/humidity resistance, resulting in only unclear images.

Comparative developer (3) has poor low-temperature fixing properties and anti-offset properties, and furthermore, it seems that the crosslinking reaction with metals is not progressing well, resulting in poor filming properties and poor durability. Particularly under high temperature and high humidity conditions, the image becomes unclear due to the instability of triboelectric charging, such as the occurrence of filming and poor cleaning, and is inferior in durability and temperature and humidity resistance.

〔Effect of the invention〕

Copying by electrophotography has become more numerous, automated, and unmanned, and there is therefore a strong demand for speeding up, guaranteeing copying image quality, and reliability, and the present invention provides a step forward in meeting these demands.

Applicant: Konishiroku Photo Industry Co., Ltd. Procedural amendment March 10, 1985

Claims (6)

[Claims] (1) Toner particles (A) whose main component is a resin obtained by reacting a carboxyl group present in a polymer component with a polyvalent metal compound, and resin-coated carrier particles (A) whose magnetic surface is coated with a resin. B) An electrostatic latent image developer containing: (2) The electrostatic charge potential according to claim 1, wherein the main component resin of the toner particles has a molecular weight distribution divided into at least two groups, a low molecular weight polymer component and a high molecular weight polymer component. Image developer. (3) In the molecular weight distribution of the main component resin, the maximum value of the low molecular weight polymer component is 1 x 10^3 to 2 x 10^4, and the maximum value of the high molecular weight polymer component is 1 x 10 ＾5〜2
10^6. (4) The polymer of the main component resin is a half-ester compound obtained by a half-esterification reaction between a styrene monomer, an acrylic acid ester monomer, an acrylic acid derivative having a hydroxyl group, and a dicarboxylic acid compound. An electrostatic latent image developer according to any one of claims 1 to 3, characterized in that it is a polymer obtained. (5) The electrostatic latent image developer according to any one of claims 1 to 4, wherein the half-ester compound is a compound represented by the following general formula (A). General formula (A) ▲ Numerical formulas, chemical formulas, tables, etc. (It may have a group.) (6) The electrostatic latent image developer according to any one of claims 1 to 5, wherein the metal compound is a zinc group metal compound or an alkaline earth metal compound.