JPH06123994A - Electrostatic charge image developing toner and image forming method - Google Patents

Abstract

PURPOSE:To improve fixing property and anti-offset property without decreasing antiblocking property and to obtain an image forming method excellent in durability without melt deposition of the toner by preparing a wax having a specified ratio of weight average mol.wt./number average mol.wt. CONSTITUTION:The image forming method includes the following processes. A contact electrifying means is brought into contact with an electrostatic latent image carrier body 1 to electrify the electrostatic latent image carrier body 1 and to form an electrostatic latent image on the electrified carrier body 1. The electrostatic latent image is developed with a toner to form a toner image. A contact transfer means is brought into contact with the electrostatic latent image carrier body 1 through a recording material to transfer the toner image. The transferred toner image is fixed to the recording material by heating and fixing means. This toner contains at least a binder resin and wax. The wax is prepared to have <=1.5 weight average mol.wt./number average mol.wt. (Mw/Mn). It is preferable that Mw/Mn<=1.5, and more preferably <=1.45, measured by GPC.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic charge image developing toner used in electrophotography, electrostatic recording and magnetic recording, and an image forming method.

[0002]

2. Description of the Related Art Conventionally, as an electrophotographic method, U.S. Pat. No. 2,297,691 and JP-B-42-23910 are known.
Although many methods are known as described in JP-B No. 43-24748 and Japanese Patent Publication No. 43-24748, generally, a photoconductive substance is used and an electric latent image is formed on a photoreceptor by various means. And then developing the latent image with toner,
After transferring the toner image to a transfer material such as paper, if necessary,
The toner is fixed by heat, pressure, heat and pressure, or solvent vapor to obtain a copy, and the toner remaining on the photoreceptor without being transferred is cleaned by various methods, and the above steps are repeated.

In recent years, such a copying apparatus has begun to be used not only as a general copying machine for copying original documents but also as a printer as an output of a computer or a personal copying machine for individuals. .

Therefore, smaller size, lighter weight, higher speed and higher reliability have been rigorously pursued, and machines have come to be composed of simpler elements in various respects. As a result, the performance required for the toner has become higher, and if the improvement in the performance of the toner cannot be achieved, a better machine cannot be established.

It is known to include wax in the toner as a fixing auxiliary component. For example, JP-A-52-3
No. 304, No. 52-3305, No. 5
Techniques such as 7-52574 are disclosed.

JP-A-3-50559 and JP-A-2-50559
79860, JP-A-1-109359, JP-A-62-14166, JP-A-61-27355.
No. 4, JP-A-61-94062, JP-A-61.
-138259, JP-A-60-252361, JP-A-60-252360 and JP-A-60-
Japanese Patent No. 217366 discloses a technique of containing waxes.

Waxes are used for improving the offset resistance of the toner at low temperature and high temperature, and for improving the fixing property at low temperature.

However, it is difficult to satisfy sufficient low temperature fixing property and blocking resistance.

On the other hand, in a printer or a copying machine using an electrophotographic technique, as a means for uniformly charging the surface of a photoconductor (electrostatic image holding member) or a means for transferring a toner image on the surface of the photoconductor, a corona Dischargers have been widely used in general, but a method of directly charging and transferring a charging member directly to the surface of a photoreceptor, applying a voltage from the outside while contacting or pressing directly or through a recording material, has been developed. It is being put to practical use.

For example, JP-A-63-149669 and JP-A-2-123385 have been proposed. These are related to the contact charging method and the contact transfer method, but a conductive elastic roller is brought into contact with the electrostatic image holder,
The electrostatic charge image carrier is uniformly charged while applying a voltage to the conductive roller, and then a toner image is obtained by an exposure / developing process, and then another voltage is applied to the electrostatic charge image carrier. The transfer material is passed while pressing the conductive elastic roller to transfer the toner image on the electrostatic image carrier to the transfer material, and then a fixing step is performed to obtain a copied image.

In such a process, since the toner is pressed against the photosensitive member by the charging member, the tendency becomes stronger when a wax which easily fuses the toner and improves the fixing property is used.

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrostatic charge image developing toner and an image forming method using the toner, which solve the above problems.

An object of the present invention is to provide a toner for developing an electrostatic charge image which is excellent in fixability at low temperature and offset resistance, and an image forming method using the toner.

An object of the present invention is to provide a toner for developing an electrostatic charge image having excellent blocking resistance and an image forming method using the toner.

An object of the present invention is to provide a toner for developing an electrostatic image which is excellent in durability and does not cause fusion with an electrostatic latent image carrier, and an image forming method using the toner.

[0016]

The present invention achieves the above object by the following constitutions.

The present invention provides a toner for developing an electrostatic image containing at least a binder resin and a wax, wherein the wax has a weight average molecular weight / number average molecular weight (M of 1.5 or less).
w / Mn).

Further, according to the present invention, the electrostatic charging means is brought into contact with the electrostatic latent image bearing member to charge the electrostatic latent image bearing member, and the electrostatic latent image bearing member is charged with the electrostatic latent image. To form a toner image by developing the electrostatic latent image with a toner, and contact the electrostatic latent image carrier with a contact transfer means through a recording material to transfer the toner image to the recording material. Then, in the image forming method of fixing the toner image to the recording material by the heat fixing means, the toner contains at least a binder resin and a wax,
The wax has a weight average molecular weight / number average molecular weight (Mw / Mn) of 1.5 or less, and relates to an image forming method.

The configuration of the present invention will be described in detail below.

Waxes are used as a component for improving the offset resistance, but on the other hand, they sometimes deteriorate the blocking resistance or easily cause fusion. Waxes are aggregates of molecules having a molecular weight distribution, and their properties largely depend on the molecular weight. In general,
The effect of waxes is not only high temperature offset resistance but also low temperature offset resistance and low temperature fixing by increasing the amount of low molecular weight components.

However, if the amount of this component is increased to improve the performance, a component having a lower molecular weight is also introduced, so that it easily changes thermally, so that the blocking resistance is deteriorated or fusion occurs. It will be easier. Therefore, if a conventional wax is adopted so that the low molecular weight is increased from the viewpoint of improving the low temperature fixing property and the low temperature offset resistance, the components of the low molecular weight are further increased and the blocking resistance, the fusion resistance and the like are deteriorated. Was.

Therefore, by making the molecular weight distribution of only the preferable molecular weight component sharp, the low-temperature fixing property and the offset resistance can be improved while the anti-blocking property and the fusion resistance are prevented from being deteriorated. It becomes possible to do.

Therefore, the wax used in the present invention is GPC.
The above-mentioned problems can be solved by having a weight average molecular weight / number average molecular weight (Mw / Mn) of 1.5 or less, preferably 1.45 or less in the molecular weight distribution measured by.

When the Mw / Mn of the wax exceeds 1.5, any one of the developing property, the fusion resistance in the image forming apparatus, the fixing property, the offset resistance and the blocking resistance is sufficient. The problem is that it will disappear.

Further, the wax used in the present invention has a number average molecular weight (Mn) of preferably 300 to 1500, more preferably 400 to 1200, and further preferably 600.
To 1000, and the weight average molecular weight (M
w) is preferably 500 to 2250, more preferably 6
It is better to have a value of 00 to 2000, more preferably 800 to 1800.

The number average molecular weight (Mn) of the wax is 300
When the amount is less than or less than 500, the low-molecular-weight component is increased and the blocking resistance is deteriorated, or the developability is deteriorated due to factors such as aging, storage, durability and humidification. When the number average molecular weight (Mn) exceeds 1500 or the weight average molecular weight (Mw) exceeds 2250, there is a tendency to cause fusion in the image forming apparatus, and the low-humidity offset resistance and low temperature fixability are deteriorated. Tend to do.

In the present invention, the molecular weight distribution of the wax is measured by gel permeation chromatography (GPC) under the following conditions. (GPC measurement conditions) Device: GPC-150C (Waters Co.) Column: GMH-HT 30 cm 2 series (manufactured by Tosoh Corporation) Temperature: 135 ° C. Solvent: o-dichlorobenzene (0.1% ionon added) Flow rate: 1.0 ml / min Sample: 0.45 ml of 0.15% sample was measured under the above conditions, and a molecular weight calibration curve prepared from a monodisperse polystyrene standard sample is used to calculate the molecular weight of the sample. Further, it is calculated by performing polyethylene conversion using a conversion formula derived from the Mark-Houwink viscosity formula.

As mentioned above, the Mw of the wax is 1.5 or less.
In order to have a sharp molecular weight distribution so as to have / Mn, press sweating method, solvent method, recrystallization method, vacuum distillation method,
It can be carried out by separating the wax according to its molecular weight using a supercritical gas extraction method or a melted liquid crystal deposition method.
In particular, a supercritical gas extraction method capable of more sharply separating the molecular weight distribution (this method allows the solvent to be separated and recovered easily because the solvent is in a gaseous state, and a molecular weight fractionated product according to the purpose), It is preferably carried out by vacuum distillation and fractionation of the distillate obtained therefrom by a melt liquid crystal precipitation and crystal filtration method.

That is, those having a low molecular weight removed by these methods, those obtained by extracting the low molecular weight, those obtained by further removing the low molecular weight, and the like having a sharp molecular weight distribution only in an arbitrary molecular weight region can be obtained. .

The method for extracting supercritical gas is described in JP-A-4-89.
As described in Japanese Patent No. 868, carbon dioxide is put into a supercritical state (high pressure state) and the raw material wax is put into a supercritical state of C.
O ₂ to thereby extract dissolved, a method for precipitating extracted dissolved wax by depressurizing the CO ₂ containing the extracted dissolved wax.

For example, throw wax into a pressure extraction tank and
When CO ₂ in a supercritical state at 30 ° C. and 300 atm is extracted and dissolved, and the pressure is reduced to 250 atm and transferred to another pressure-resistant separation tank, the wax in the high melting point portion is separated and separated. Further, if CO ₂ containing unseparated wax is decompressed to 200 atm and transferred to another pressure-resistant separation tank, the next high melting point portion is separated.
By repeating this, the raw wax is separated according to the molecular weight according to the number of depressurization operations.

The CO ₂ pressure-temperature change in the supercritical state, especially the extraction solubility of the wax with respect to the pressure, is large, and its dependence greatly differs depending on the molecular weight of the washes. Therefore, the molecular weight distribution of the separated waxes becomes narrower as the number of separation operations (the number of differences in depressurization pressure) is increased or the pressure difference between two points of depressurization pressure is decreased.

Further, all the waxes may be dissolved at the time of the first extraction and dissolution, or a lower pressure condition may be adopted, which is a condition for leaving a part of the high melting point wax.

Further, a method of successively depressurizing the extracted and dissolved wax mixed gas may be employed, or a method of obtaining a fractionated wax by sequentially changing the extraction conditions in the extraction tank.

CO ₂ is preferably used as the extraction gas, but supercritical gases such as ethane, ethylene and propane can also be used. Furthermore, an organic solvent (toluene or the like) may be added to these gases. Extraction temperature is room temperature to 300
It is carried out in the range up to ℃, but from the extraction efficiency, 100 ~
200 ° C. is preferred. The pressure at the time of extraction may be any pressure as long as it becomes a medium (gas) critical state, but in the case of CO ₂ , it is 75 to 300 atm, although it depends on the extraction temperature. The pressure at the time of separation may be appropriately selected at a pressure equal to or lower than the pressure at the time of extraction.

Vacuum distillation and a method for separating a distillate obtained therefrom by melting liquid crystal and filtering the crystals are disclosed in JP-A-4-14510.
As described in Japanese Patent Publication No. 3
The lower molecular weight fraction is distilled off, the distillate is melted, the temperature of the melt is lowered, the crystals are partially crystallized, and the crystals are partially separated by filtration. ) Is how to get.

It is preferable that a plurality of distillates are obtained by distillation. That is, a low-molecular-weight one is distilled out by the first distillation distillation, and then a higher-molecular-weight component is distilled off at a higher temperature or a higher reduced pressure than the distillate residual liquid. By repeating the treatment, the high molecular weight side can be sequentially distilled off.

The crystallized products obtained by performing melt crystallization and crystal filtration from the distillates having different molecular weights were obtained from the crystallized products obtained by the melt crystallization filtration from a single distillation distillate. A wax having a narrow molecular weight distribution can be obtained. It is preferable to use a plurality of distillates from the raw washes as described above to obtain a fractionated wax having a narrow molecular weight distribution.

The distillative extraction operation can be carried out by the existing apparatus and method. For example, first grade distillation is 5-8 mmHg, 260-
At 290 ° C, the second stage is 0.1-0.01 mmHg, 25
0 ~ 270 ℃, the third stage is 0.01mmHg, 290 ℃
Then, the fourth step is performed at 0.001 mmHg and 290 ° C. At this time, it is preferable to use a thin film distillation apparatus or the like for the second to fourth stages of distillation in order to perform the distillation efficiently. Naturally, this distillation condition is modified by the fraction wax to be obtained. Then, the distillate is heated at a predetermined temperature to melt it. This is cooled, a crystal is partially precipitated, and the crystal substance and the melt are separated by a filter. The filtered first-stage crystalline product is one on the high molecular weight side in the distillation distillation portion, that is, one having a high melting point. The crystalline substance filtered off from this mixture is
A wax fraction with a narrow molecular weight distribution.

On the other hand, the temperature of the melt that has passed through the uncrystallized filter is further lowered, and second-stage crystals having a lower molecular weight than the previous crystallized substance, that is, a lower melting point, are precipitated. Separate them separately. Here, the uncrystallized melt is further cooled, and similarly crystallized and filtered to obtain a crystallized product in the third stage.

By repeating such melt-liquid crystal deposition and crystal filtration, a plurality of wax fractions having different molecular weight distributions from a high molecular weight side, that is, a high melting point to a low molecular weight side, that is, a low melting point can be obtained. . Crystallization from the melt
It is also possible to employ a method in which the temperature is continuously lowered and the precipitated crystals in a certain temperature range are filtered off.

Further, the crystal precipitation rate when performing melted liquid crystal deposition varies depending on the number of repetitions of melted liquid crystal deposition, the molecular weight distribution and the melting point of the fractionated wax. For example, if the distillation distillate is divided into two equal amounts by one crystallization filtration, the crystal yield may be 50%.

Generally, a crystal product having a crystal yield of 70% or less, preferably 50% or less is a fractionated wax having a narrow molecular weight distribution.

Crystallization of the melt may be a generally conceivable method. That is, the raw wax may be heated and melted in a container, cooled to a predetermined temperature, and partially crystallized. At this time, it may not be completely melted, and some unmelted matter may be present. The cooling rate may be any rate, but slow cooling is preferable.

When precipitating the crystals, a crystallization aid, for example, an inorganic substance such as talc, a metal salt of a higher fatty acid, a polymer such as polyethylene having a melting point higher than that of the raw wax may be added. It is also possible to add stirring.

The precipitated crystals and the melt may be separated by filtration with a general filter. If pressure is applied by suction or pressing, it will be filtered more quickly.

Further, the wax used in the present invention is an endothermic peak at the time of temperature rise in the DSC curve measured by a differential scanning calorimeter, and the onset temperature of the peak is preferably 50 ° C. or higher, within the range of 50 to 120 ° C. Is particularly preferable, and more preferably 50 to 110 ° C. Furthermore,
The peak top temperature of the maximum endothermic peak is preferably 130 ° C or lower, and particularly preferably in the range of 70 to 130 ° C. When the temperature is raised, changes can be seen when heat is applied to the wax, and endothermic peaks associated with wax transition and melting are observed. Peak onset temperature is 50
Within the range of 120 to 120 ° C., the developability, blocking resistance, and low-temperature fixability can be particularly preferably satisfied. If the peak onset temperature is less than 50 ° C., the wax change temperature is too low, and the blocking resistance is poor, or the toner tends to be poor in developability at the time of temperature rise. If it exceeds 120 ° C., the change temperature of the wax is too high, and it tends to be difficult to obtain sufficient fixing property. The presence of the maximum endothermic peak at 130 ° C. or lower, preferably in the range of 70 to 130 ° C., and particularly preferably in the range of 85 to 120 ° C. makes it possible to satisfy particularly good fixability and offset resistance. When the peak temperature of the maximum peak exists below 70 ° C., the melting temperature of the wax is too low and sufficient high temperature offset resistance cannot be obtained.
When the peak temperature of the maximum peak exists in the region exceeding ℃, the melting temperature of the wax is too high, and it tends to be difficult to obtain sufficient low temperature offset resistance and low temperature fixability.
That is, the presence of the maximum peak temperature in this region facilitates the balance between offset resistance and fixability.

Further, in order to improve the high temperature offset resistance, the onset temperature at the end point of the endothermic peak is preferably 80 ° C. or higher, more preferably 80 to 140 ° C., further 90 to 130 ° C. Yes, 100-130 ℃
Is particularly preferable.

Furthermore, the difference between the onset temperature at the end point and the onset temperature is 70 to 5 ° C., preferably 60 to 10 ° C., more preferably 50 to 10 ° C.

By doing so, it becomes easy to balance low-temperature fixability, offset resistance, blocking resistance, developability and the like. For example, if the temperature range is wider than this range, the blocking resistance may be poor even if the low temperature fixability and the offset resistance are obtained.

In the present invention, since the heat exchange of the wax is measured and the behavior thereof is observed in the DSC measurement, it is preferable to measure with a highly accurate internal heat type input compensation type differential scanning calorimeter from the principle of measurement. For example, DSC-7 manufactured by Perkin Elmer can be used.

The measuring method is ASTM D3418-82.
Carry out according to. The DSC curve used in the present invention has a temperature rate of 10 ° C./m after the temperature has been raised and lowered once and the previous history is taken.
In, a DSC curve measured when the temperature is raised is used. The definition of each temperature is defined as follows.

Onset temperature of endothermic peak The temperature at the intersection of the tangent to the curve and the base line at the point where the differential value of the DSC curve at the time of temperature rise reaches its maximum.

Peak Top Temperature of Maximum Peak The peak top temperature of the peak with the highest height from the baseline.

Onset temperature at the end point of the endothermic peak The temperature at the intersection of the tangent line of the curve and the base line at the point where the differential value of the curve at the time of temperature rise becomes the minimum.

The wax used in the present invention is obtained from the following waxes. Paraffin wax and its derivatives, montan wax and its derivatives,
Examples include microcrystal wax and its derivatives, Fischer-Tropsch wax and its derivatives, polyolefin washes and their derivatives, and the derivatives include oxides, block copolymers with vinyl monomers, and graft modified products.

As other waxes, alcohols and their derivatives, fatty acids and their derivatives, acid amides, esters, ketones, hydrogenated castor oil and its derivatives, vegetable waxes, animal waxes, mineral waxes, petrolactam can also be used. The derivatives include saponified products, salts, alkylene oxide adducts, and esters.

Among them, waxes preferably used are low molecular weight polyolefins obtained by radical polymerization of olefins under high pressure or polymerization using a Ziegler catalyst and by-products at this time; low molecular weights obtained by thermally decomposing high molecular weight polyolefins. A wax obtained from a distillation residue of a hydrocarbon obtained by using a catalyst from a synthesis gas composed of carbon monoxide and hydrogen, or a synthetic hydrocarbon obtained by hydrogenating these, and an antioxidant. May be added. Alternatively, it is a linear alcohol, an alcohol derivative, a fatty acid, an acid amide, an ester, or a montan derivative. Furthermore, it is also preferable that fatty acid impurities have been removed in advance.

Particularly preferred are those obtained by polymerizing an olefin such as ethylene with a Ziegler catalyst, and by-products at this time, and those having a hydrocarbon having a carbon number of several thousand, particularly up to about 1,000, such as Fischer-Tropsch wax. Is good.

Furthermore, it is also possible to use a wax obtained by oxidizing the wax separated after the wax is separated by the above-mentioned method, a block copolymer, or a graft-modified wax.

As other physical properties of the washer, the penetration at 25 ° C. is preferably 10.0 or less,
It is particularly preferably 5.0 or less. Furthermore, 140 ℃
The melt viscosity in is preferably 200 cP or less. Penetration is a value measured according to JIS K-2207, and melt viscosity is a value measured using a Brookfield viscometer.

In the toner of the present invention, the content of these waxes is 20 parts by weight or less, preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the binder resin. . Further, it may be used in combination with other waxes.

The following binder resins can be used as the binder resin used in the toner of the present invention.

For example, homopolymers of styrene and its substitution products such as polystyrene, poly-p-chlorostyrene and polyvinyltoluene; styrene-p-chlorostyrene copolymers, styrene-vinyltoluene copolymers, styrene-
Vinyl naphthalene copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-
Styrene such as vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer -Based copolymer; further, polyvinyl chloride, phenol resin, naturally modified phenol resin,
Natural resin modified maleic acid resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester resin, polyurethane, polyamide resin, furan resin, epoxy resin, xylene resin, polyvinyl butyral, terpene resin, coumarone indene resin, petroleum-based Resin can be used. Examples of preferable binder substances include styrene-based copolymers and polyester resins.

Examples of the comonomer for the styrene monomer of the styrene copolymer include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate,
Duplex such as dodecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide A monocarboxylic acid having a bond or a substituted product thereof; for example, a dicarboxylic acid having a double bond such as maleic acid, butyl maleate, methyl maleate, dimethyl maleate and a substituted product thereof; for example, vinyl chloride, vinyl acetate, benzoate Vinyl esters such as acid vinyl: Ethylenic olefins such as ethylene, propylene and butylene; Vinyl ketones such as vinyl methyl ketone and vinyl hexyl ketone; Chirueteru, vinyl ethers such as vinyl isobutyl ether; such vinyl monomers are used alone or two or more.

The styrene polymer or styrene copolymer may be crosslinked or may be a mixed resin.

As the crosslinking agent for the binder resin, a compound having two or more polymerizable double bonds can be mainly used. For example, aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; carboxylic acid esters having two double bonds such as ethylene glycol diacrylate, ethylene glycol dimethacrylate, and 1,3-butanediol dimethacrylate; divinylaniline. , Divinyl ether, divinyl sulfide and divinyl sulfone, and compounds having 3 or more vinyl groups are used alone or as a mixture.

In the developer of the present invention, it is preferable to use a charge control agent in the developer particles (internal addition) or to mix with the developer particles (external addition). The charge control agent makes it possible to optimally control the charge amount according to the developing system, and particularly in the present invention, it is possible to further stabilize the balance between the particle size distribution and the charge. Examples of the positive charge control agent include modified products of nigrosine and fatty acid metal salts; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonic acid, tetrabutylammonium tetrafluoroborate, and analogs thereof. Onium salts such as certain phosphonium salts and lake pigments thereof, triphenylmethane dyes and lake pigments thereof (as a laker, phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid, tannic acid, lauric acid, gallic acid) Acids, ferricyanides, ferrocyanides) metal salts of higher fatty acids; diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide; dibutyltin borate, dioctyl Zuboreto, such diorgano tin borate such dicyclohexyl tin borate; these alone, or two
Combinations of more than one type can be used. Among these, charge control agents such as nigrosine, quaternary ammonium salts and triphenylmethane pigments are particularly preferably used.

Further, the following general formula

[0070]

[Outer 1] [R ₁ : H, CH ₃ R ₂ , R ₃ : a substituted or unsubstituted alkyl group (preferably C _{1 to} C ₄ )], a homopolymer of a monomer: styrene, an acrylic ester, or methacryl described above. A copolymer with a polymerizable monomer such as an acid ester can be used as a positive charge control agent. In this case, these charge control agents also function as (all or part of) the binder resin.

The following substances may be mentioned as examples of controlling the toner to be negatively charged.

Organic metal complexes and chelate compounds are effective, for example, monoazo metal complexes, acetylacetone metal complexes, aromatic hydroxycarboxylic acids, and aromatic dicarboxylic acid metal complexes. Others include aromatic hydroxycarboxylic acids, aromatic mono- and polycarboxylic acids and their metal salts, anhydrides, esters, and phenol derivatives such as bisphenol.

The above-mentioned charge control agent (which does not act as a binder resin) is preferably used in the form of fine particles. In this case, the number average particle size of this charge control agent is
Specifically, it is preferably 4 μm or less (further, 3 μm or less).

When internally added to the developer, such a charge control agent is preferably used in an amount of 0.1 to 20 parts by weight (more preferably 0.2 to 10 parts by weight) per 100 parts by weight of the binder resin. .

In the toner of the present invention, it is preferable to add fine silica powder in order to improve charge stability, developability, fluidity and durability.

The silica fine powder used in the present invention is BE.
Specific surface area due to nitrogen adsorption measured by T method is 30 m ² / g
Those in the above range (particularly 50 to 400 m ² / g) give good results. The fine silica powder is used in an amount of 0.01 to 8 parts by weight, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the toner.

The silica fine powder used in the present invention may contain a silicone varnish, various modified silicone varnishes, silicone oil, various modified silicone oil, a silane coupling agent, and a functional group, if necessary, for the purpose of hydrophobizing and controlling chargeability. It is also preferable that the silane coupling agent is treated with a treating agent such as another silane coupling agent or an organic silicon compound, or is used in combination with various treating agents.

Further, as other additives to the toner, lubricant powders such as Teflon powder, zinc stearate powder, polyvinylidene fluoride powder, and among others, polyvinylidene fluoride is preferable. Alternatively, abrasives such as cerium oxide powder, silicon carbide powder, and strontium titanate powder, among which strontium titanate is preferable. Alternatively, a fluidity-imparting agent such as titanium oxide powder and aluminum oxide powder, and particularly hydrophobic ones are preferable. A small amount of an anti-caking agent or a conductivity-imparting agent such as carbon black powder, zinc oxide powder, antimony oxide powder, tin oxide powder, or white and black particles of opposite polarity can be used as a developing property improver.

When the toner of the present invention is used as a two-component developer, it is used as a mixture with carrier powder. In this case, the mixing ratio of the toner and the carrier powder is preferably 0.1 to 50% by weight, more preferably 0.5 to 10% by weight, still more preferably 3 to 10% as the toner concentration.
Weight% is good.

As the carrier that can be used in the present invention, known carriers can be used. For example, magnetic powder such as iron powder, ferrite powder and nickel powder, glass beads and the surface thereof made of a fluororesin, Examples include those treated with a vinyl resin or a silicone resin.

Further, the toner of the present invention can be used as a one-component developer using a magnetic toner by further containing a magnetic material. In this case, the magnetic material can also serve as a coloring agent. In the present invention, the magnetic material contained in the magnetic toner includes iron oxide such as magnetite, hematite and ferrite; metals such as iron, cobalt and nickel, or aluminum, cobalt, copper and lead of these metals;
Magnesium, tin, zinc, antimony, beryllium,
Mention may be made of alloys of metals such as bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium and mixtures thereof.

These ferromagnetic materials have an average particle size of 2 μm or less, preferably about 0.1 to 0.5 μm. The amount contained in the toner is preferably about 20 to 200 parts by weight, particularly preferably 40 to 150 parts by weight, based on 100 parts by weight of the resin component.

Further, the magnetic material has a magnetic property with a coercive force ratio (Hc) of 20 to 300 oersted, a saturation magnetic ratio (σs) of 50 to 200 emu / g, and a residual magnetic ratio (σr) of 2 to 20 emu / when a 10 K oersted is applied. g is preferable.

The colorant that can be used in the toner of the present invention includes any appropriate pigment or dye. As the colorant of the toner, for example, carbon black as a pigment,
There are aniline black, acetylene black, naphthol yellow, hansa yellow, rhodamine lake, alizarin lake, red iron oxide, phthalocyanine blue, and indanthrene blue. These are used in an amount necessary and sufficient for maintaining the optical density of the fixed image, and preferably the resin 1
The amount added is preferably 0.1 to 20 parts by weight, more preferably 0.2 to 10 parts by weight with respect to 00 parts by weight.

Further, a dye is further used for the same purpose. Examples include azo dyes, anthraquinone dyes, xanthene dyes, and methine dyes, which are preferably added in an amount of 0.1 to 20 parts by weight, more preferably 0.3 to 10 parts by weight, based on 100 parts by weight of the resin. The quantity is good.

To prepare the toner for developing an electrostatic charge image according to the present invention, a binder resin and washes, a metal salt or a metal complex, a pigment or dye as a colorant, a magnetic substance, and optionally other toner components. The charge control agent, which is a component, and other additives are sufficiently mixed by a mixer such as a Henschel mixer or a ball mill, and then melt-kneaded by using a heat kneader such as a heating roll, a kneader, or an extruder to make the resins mutually. Metal compounds, pigments, dyes, etc.
The toner according to the present invention can be obtained by dispersing or dissolving a magnetic material, cooling and solidifying, and then pulverizing and classifying.

Further, if desired, desired additives may be sufficiently mixed with a mixer such as a Henschel mixer to obtain the electrostatic image developing toner according to the present invention.

Next, an example of an image forming method having the contact charging means and the contact transfer means of the present invention will be described based on the schematic configuration diagram of FIG.

Reference numeral 1 denotes a rotary drum type electrostatic latent image carrier (hereinafter referred to as a photoconductor). The photoconductor 1 has a conductive base layer 1b such as aluminum and a photoconductive layer 1a formed on the outer surface thereof. Is a basic constituent layer, and is rotated clockwise in the drawing at a predetermined peripheral speed (process speed).

Reference numeral 2 denotes a charging roller as a contact charging means, which has a basic structure of a cored bar 2b at the center and a conductive elastic layer forming the outer periphery thereof. The charging roller 2 is
The photosensitive member 1 is pressed against the surface of the photosensitive member 1 with a pressing force, and is rotated by the rotation of the photosensitive member 1. A charging bias power source 3 applies a voltage to the charging roller 2. By applying a bias to the charging roller 2, the surface of the photoconductor 1 is charged to a predetermined polarity and potential. Then, an electrostatic latent image is formed by image exposure 4, and the toner image is sequentially visualized as a toner image by the developing unit 5 having toner.

Reference numeral 6 denotes a transfer roller as a contact transfer means, which basically has a cored bar 6b at the center and a conductive elastic layer 6a forming the outer periphery thereof. Transfer roller 6
Is pressed against the surface of the photoconductor 1 at least at the time of transfer via the recording material 8 with a pressing force, and is rotated at a constant speed or a peripheral speed different from that of the photoconductor 1. The recording material 8 is the photoconductor 1.
The toner image on the photoconductor 1 is transferred onto the surface of the recording material 8 by applying a bias having a polarity opposite to the toner triboelectric charge from the transfer bias power source 7 to the transfer roller 6 at the same time when the toner image is conveyed between the transfer roller 6 and the transfer roller 6. Transferred to the side.

Next, the recording material 8 is conveyed to a fixing device 11 which has a heating roller 11a containing a halogen heater and an elastic pressure roller 11b pressed against the heating roller 11a as a basic structure, and 11a and 11b. The toner image is fixed by passing through the space. After the toner image is transferred, on the surface of the photosensitive member 1, adhered contaminants such as untransferred toner,
The cleaning surface is formed by a cleaning device equipped with an elastic cleaning blade pressed against the photoconductor 1 in the counter direction,
Further, the charge is removed by the charge removing exposure device 10, and the image is repeatedly formed. Further, a method of fixing with a heater through a film may be used.

In the image forming apparatus having such contact charging means or contact transfer means, compared with corona charging or corona transfer, it is possible to uniformly charge the photoreceptor and sufficiently transfer it with a relatively low voltage bias. Therefore, it is excellent in miniaturizing the discharger itself and suppressing corona discharge products such as ozone.

Other contact charging means include a method using a charging blade and a method using a conductive brush. These contact charging means have the effects of not requiring high voltage and reducing the generation of ozone, but
Generally, since the member directly contacts the photoreceptor, the problem of toner fusion tends to occur, but the use of the toner of the present invention is preferable because such a problem does not occur. The present invention does not limit what kind of method and what kind of effect the applied contact charging means has, and any method of charging a member by directly contacting it with a photoconductor is applied to the present invention. It is possible.

A preferable process condition when the charging roller is used is that the contact pressure of the roller is 5 to 500 g / c.
In m, when a DC voltage superimposed with an AC voltage is used, AC voltage = 0.5 to 5 kVpp, AC frequency = 50
~ 5 kHz, DC voltage = ± 0.2 to ± 1.5 kV, and when using DC voltage, DC voltage = ± 0.2 to ±
It is 5 kV.

As a material for the charging roller and the charging blade, conductive rubber is preferable, and a releasing film may be provided on the surface thereof. As the releasable coating, nylon resin,
PVDF (polyvinylidene fluoride), PVDC (polyvinylidene chloride), etc. are applicable.

The material of the transfer rotary member applicable to the present invention may be the same as that of the charging roller, and the preferable transfer process condition is that the contact pressure of the roller is 5 to 500 g / cm. , DC voltage is ± 0.2 ~
± 10 kV.

[0098]

EXAMPLES The present invention will be described below with reference to specific examples, but the present invention is not limited thereto.

The molecular weight of the wax used in the present invention is
Table 1 shows each characteristic.

In the table, the washer name -1 is the original wax, and -2, -3 and -4 are the waxes after fractionation. C
Is a low molecular weight polyethylene which is a by-product when polyethylene is polymerized mainly with ethylene by a Ziegler catalyst.

A-2, A-3, B-2, C-3, D-
2, F-2 and G-2 are waxes fractionated by a supercritical gas extraction method, and B-3, C-2 and E-2 are vacuum distillation and distillate obtained therefrom are subjected to liquid crystal precipitation and crystallization. The wax was separated by the method of filtering, and the wax B-4 was separated by the recrystallization method.

(Waxes A-2, A-3, B-2, C-
Preparation of 3, D-2, F-2 and G-2) Using the supercritical gas extraction method, the wax A-1 is put into the pressure resistant extraction tank,
Extracted and dissolved in supercritical CO ₂ at 130 ° C. and 300 atm, reduced the pressure to 200 atm and transferred to another pressure-resistant separation tank to deposit and separate the wax in the high-melting point portion, and to show the physical properties shown in Tables 1 and 2. Wax A-2 having Furthermore, the wax raw material, the deposition pressure and the number of divisions were changed as appropriate.
And waxes A-3, B-2 having the properties shown in Table 2.
C-3, D-2, F-2 and G-2 were obtained respectively.

(Preparation of Wax B-3, C-2 and E-2) Wax B-1 was used to carry out the first stage distillation at 3 mmH.
g, 180-300 ° C., second stage distillation 0.2 m
Perform mHg at 250 ° C and distill the third stage to 0.02 mm.
Hg, performed at 280 ℃, 4th stage distillation 0.01mmH
g at 280 ° C., and then the distillate was subjected to melt liquid crystal precipitation and crystal filtration to obtain a wax B- having the physical properties shown in Tables 1 and 2.
Got 3. Further, the wax raw materials, the distillation pressure, the distillation temperature and the number of times of distillation were appropriately changed to obtain waxes C-2 and E-2 having the physical properties shown in Tables 1 and 2, respectively.

(Preparation of Wax B-4) Wax B-1
Wax B-4 having the physical properties shown in Table 1 and Table 2 was obtained by the recrystallization method.

[0105]

[Table 1]

[0106]

[Table 2]

Example 1 Styrene-butyl acrylate copolymer 100 parts by weight Magnetic iron oxide 80 parts by weight Nigrosine 2 parts by weight Wax (A-2) 4 parts by weight

After the above materials were premixed, they were melt-kneaded by a twin-screw kneading extruder set at 130 ° C. The kneaded product was cooled, coarsely pulverized, finely pulverized by a pulverizer using a jet stream, and further classified by an air classifier to obtain toner particles having a weight average particle diameter of 8 μm. To 100 parts by weight of the above toner particles, 0.6 part by weight of positively charged hydrophobic colloidal silica was externally added to obtain a toner, which was used as a one-component developer.

Various evaluations were carried out using a commercially available electrophotographic copying machine NP-6030 (manufactured by Canon Inc., using contact charging means and contact transfer means). The results are shown in Table 3.

(Fixability Test) In the first copy test,
The fixability was evaluated. The fixing property was evaluated by rubbing the image with sillbon paper 10 times reciprocatingly under a load of about 100 g, and peeling of the image was evaluated by the reduction rate (%) of reflection density.

(Offset test) A transfer paper of B5 is set to 200
Immediately after the sheets were continuously taken, a copy was made on the transfer paper of A3, and the high temperature offset due to the temperature rise at the edges was evaluated by the occurrence of image contamination.

(Durability Test) A durability test of 10,000 sheets was carried out by A4 longitudinal feeding to evaluate image density, fog and fusion. Here, the utilization rate is the proportion of toner that is transferred onto an image among the consumed toner, and is calculated by the following equation.
When this value is large, it means that the toner is effectively used, the amount of waste toner is small, the toner consumption is small, and a copy having a high image density can be obtained. {(Amount of toner consumed-amount of waste toner in the cleaner) /
(Amount of toner consumed)} × 100 (Blocking test) About 20 g of a developer was placed in a 100 cc poly cup and left at 50 ° C. for 3 days, and then visually evaluated. Excellent: Agglomerates are not seen Good: Agglomerates are seen but easily collapsed Possible: Agglomerates are seen but collapsed if shaken No: Aggregates can be grabbed and not easily collapsed Example 2 Styrene-butyl Acrylate copolymer 100 parts by weight Magnetic iron oxide 80 parts by weight Nigrosine 2 parts by weight Wax (A-3) 4 parts by weight

Using the above materials, in the same manner as in Example 1,
A one-component developer was prepared and evaluated. The results are shown in Table 3.

Example 3 Styrene-butyl acrylate copolymer 100 parts by weight Magnetic iron oxide 80 parts by weight Nigrosine 2 parts by weight Wax (B-2) 4 parts by weight

Using the above materials, in the same manner as in Example 1,
A one-component developer was prepared and evaluated. The results are shown in Table 3.

Example 4 Styrene-butyl acrylate copolymer 100 parts by weight Magnetic iron oxide 80 parts by weight Nigrosine 2 parts by weight Wax (B-3) 4 parts by weight

Using the above materials, in the same manner as in Example 1,
A one-component developer was prepared and evaluated. The results are shown in Table 3.

Example 5 Styrene-butyl acrylate copolymer 100 parts by weight Magnetic iron oxide 80 parts by weight Nigrosine 2 parts by weight Wax (C-2) 4 parts by weight

Using the above materials, in the same manner as in Example 1,
A one-component developer was prepared and evaluated. The results are shown in Table 3.

Example 6 Styrene-butyl acrylate copolymer 100 parts by weight Magnetic iron oxide 80 parts by weight Nigrosine 2 parts by weight Wax (C-3) 4 parts by weight

Using the above materials, in the same manner as in Example 1,
A one-component developer was prepared and evaluated. The results are shown in Table 3.

Example 7 Styrene-butyl acrylate copolymer 100 parts by weight Magnetic iron oxide 80 parts by weight Nigrosine 2 parts by weight Wax (D-2) 4 parts by weight

Using the above materials, in the same manner as in Example 1,
A one-component developer was prepared and evaluated. The results are shown in Table 3.

Example 8 Styrene-butyl acrylate copolymer 100 parts by weight Magnetic iron oxide 80 parts by weight Nigrosine 2 parts by weight Wax (E-2) 4 parts by weight

Using the above materials, in the same manner as in Example 1,
A one-component developer was prepared and evaluated. The results are shown in Table 3.

Example 9 Styrene-butyl acrylate copolymer 100 parts by weight Magnetic iron oxide 80 parts by weight Nigrosine 2 parts by weight Wax (F-2) 4 parts by weight

Using the above materials and in the same manner as in Example 1,
A one-component developer was prepared and evaluated. The results are shown in Table 3.

Example 10 Styrene-butyl acrylate copolymer 100 parts by weight Magnetic iron oxide 80 parts by weight Nigrosine 2 parts by weight Wax (G-2) 4 parts by weight

Using the above materials, in the same manner as in Example 1,
A one-component developer was prepared and evaluated. The results are shown in Table 3.

Comparative Example 1 Styrene-butyl acrylate copolymer 100 parts by weight Magnetic iron oxide 80 parts by weight Nigrosine 2 parts by weight Wax (A-1) 4 parts by weight

Using the above materials, in the same manner as in Example 1,
A one-component developer was prepared and evaluated. The results are shown in Table 3.

Comparative Example 2 100 parts by weight of styrene-butyl acrylate copolymer 80 parts by weight of magnetic iron oxide 2 parts by weight of nigrosine 4 parts by weight of wax (B-1)

Using the above materials, in the same manner as in Example 1,
A one-component developer was prepared and evaluated. The results are shown in Table 3.

Comparative Example 3 Styrene-butyl acrylate copolymer 100 parts by weight Magnetic iron oxide 80 parts by weight Nigrosine 2 parts by weight Wax (D-1) 4 parts by weight

Using the above materials, in the same manner as in Example 1,
A one-component developer was prepared and evaluated. The results are shown in Table 3.

Comparative Example 4 Styrene-butyl acrylate copolymer 100 parts by weight Magnetic iron oxide 80 parts by weight Nigrosine 2 parts by weight Wax (E-1) 4 parts by weight

Using the above materials, in the same manner as in Example 1,
A one-component developer was prepared and evaluated. The results are shown in Table 3.

Comparative Example 5 Styrene-butyl acrylate copolymer 100 parts by weight Magnetic iron oxide 80 parts by weight Nigrosine 2 parts by weight Wax (B-4) 4 parts by weight

Using the above materials, in the same manner as in Example 1,
A one-component developer was prepared and evaluated. The results are shown in Table 3.

[0140]

[Table 3]

Example 11 Various evaluations were carried out by using the one-component type developer used in Example 1 with a commercially available electrophotographic copying machine NP-4080 (manufactured by Canon Inc., using corona charging means and corona transfer means). . The results are shown in Table 4.

(Fixability Test) In the first copy test,
The fixability was evaluated. The fixing property was evaluated by rubbing the image with sillbon paper 10 times reciprocatingly under a load of about 100 g, and peeling of the image was evaluated by the reduction rate (%) of reflection density.

(Offset test) The transfer paper of B5 is 200
Immediately after the sheets were continuously taken, a copy was made on the transfer paper of A3, and the high temperature offset due to the temperature rise at the edges was evaluated by the occurrence of image contamination.

(Durability Test) A durability test of 10,000 sheets was conducted to evaluate image density, fogging, fusing, and utilization rate.

Examples 12-20 Evaluations were made in the same manner as in Example 10 using the one-component type developer used in Examples 2-10. The results are shown in Table 4.

[0146]

[Table 4]

[0147]

As described above, the toner of the present invention is 1.5
Since a wax having the following Mw / Mn and a very sharp molecular weight distribution is used, the fixing property and the offset resistance can be improved without impairing the blocking resistance, and the fusion resistance does not occur. An excellent image forming method can be obtained. Further, a toner having excellent transferability and good utilization rate can be obtained, and an image with high image density and no fog can be obtained with a low consumption amount.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram for explaining an image forming method of a contact charging unit and a contact transfer unit according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrostatic charge image carrier (photoreceptor) 2 Charging roller 3 Charging bias applying power source 4 Image exposure 5 Developing means 6 Transfer roller 7 Transfer bias applying power source 8 Transfer material 9 Cleaning means 10 Static erasing exposure 11 Fixing means

Claims (8)

[Claims] 1. In an electrostatic charge image developing toner containing at least a binder resin and a wax, the wax is
Weight average molecular weight of 1.5 or less / number average molecular weight (Mw / M
n) is included in the toner for developing an electrostatic charge image. 2. The wax has a weight-average molecular weight / number-average molecular weight (Mw / Mn) obtained by fractionating the waxes by molecular weight.
2. The toner for developing an electrostatic charge image according to claim 1, which is a wax having a ratio of 1.5 or less. 3. The static wax according to claim 1, wherein the wax has an onset temperature of an endothermic peak at a temperature of 50 ° C. or higher in a DSC curve measured by a differential scanning calorimeter. Toner for charge image development. 4. The wax has a peak top temperature of a maximum endothermic peak at a temperature rise of 130 ° C. or lower in a DSC curve measured by a differential scanning calorimeter. Toner for developing electrostatic images. 5. A contact charging unit is brought into contact with the electrostatic latent image carrier to charge the electrostatic latent image carrier, and an electrostatic latent image is formed on the charged electrostatic latent image carrier. The electrostatic latent image is developed with toner to form a toner image, and the electrostatic latent image carrier is brought into contact with a contact transfer means via a recording material to transfer the toner image to the recording material. In the image forming method of fixing an image on the recording material by a heat fixing unit, the toner contains at least a binder resin and washes, and the washes have a weight average molecular weight / number average molecular weight (1.5 or less). An image forming method characterized by having Mw / Mn). 6. The image formation according to claim 5, wherein the washer is a wax having a weight average molecular weight / number average molecular weight (Mw / Mn) of 1.5 or less by being classified by molecular weight. Method. 7. The image according to claim 5, wherein the wax has an onset temperature of an endothermic peak at a temperature of 50 ° C. or higher in a DSC curve measured by a differential scanning calorimeter. Forming method. 8. The wax according to claim 5, wherein the peak end temperature of the maximum endothermic peak at the time of temperature rise is 130 ° C. or lower in the DSC curve measured by a differential scanning calorimeter. Image forming method.