JP2000003066A - Toner for electrostatic charge development - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a toner for electrostatic charge development giving a good image almost free from fog. SOLUTION: The toner is a negative charge type nonmagnetic one-component toner contg. at least a polyester resin, a colorant, an electrostatic charge controlling agent and inorg. fine particles. When an AC electric field having 1.5 kHz frequency is applied to the toner, the dielectric constant ε' and dielectric tangent tan δ of the toner satisfy the inequality. The inorg. fine particles comprise fine hydrophobic silica powder having <=20 nm average particle diameter and fine hydrophobic silica powder having >=30 nm average particle diameter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a negatively charged non-magnetic one-component toner containing at least a polyester resin, a colorant and inorganic fine particles.

[0002]

[Prior art]

[0003] Many methods are known as a developing method in electrophotography.
There are a two-component developing method using a mixture of a carrier composed of fine particles (20 to 500 μm) of nickel, glass or the like and a toner as a developer, and a one-component developing method using a developer composed of only a toner. In either method, generally, the toner particles are charged by friction.

[0004] In the two-component developing method, a good image can be obtained relatively stably, but on the other hand, the quality of the image due to the contamination of the carrier surface by the toner or the like and the change in the triboelectric charging property due to the fluctuation of the mixing ratio of the carrier and the toner. Degradation and the like are likely to occur. For this reason, various devices and materials have been devised as preventive measures.

The one-component developing method includes a magnetic one-component method in which magnetism is imparted to a toner and a non-magnetic one-component method in which magnetism is not imparted.

[0006] The magnetic one-component developing method is a two-component developing method in which the contamination of the carrier surface by toner and the like, and the deterioration of the image quality due to the change in the triboelectrification due to the change of the mixing ratio of the carrier and the toner are apt to occur. The object of the present invention is to avoid the problems of the developing method. For example, US Pat. No. 4,336,318
The specification describes a method of developing using an electrically insulating magnetic toner. In these methods, the toner is charged by frictional charging between the toner particles and the toner carrier and the toner thinning member, or by frictional charging between the toner particles, and the electrostatic latent image on the photosensitive member is electrostatically charged. Attached.

This developing method can avoid the problems of the two-component developing method since no carrier is used and no device for controlling the mixing ratio of the carrier and the toner is required. It has the advantage of being compact.

In recent years, a non-magnetic one-component developing method which does not require magnetic properties of toner has been proposed. Various devices have been studied as a non-magnetic one-component developing method.
In many cases, toner is adhered to a developing sleeve or the like as a developer carrier by electrostatic force, and the toner is transported to an electrostatic latent image surface on an electrostatic latent image carrier such as a photoconductor and developed. Compared with the conventional magnetic one-component developing method, the point that the magnetic material is not an essential component in the configuration of the toner to be used is greatly different, and it is expected that the problems caused by the inclusion of the magnetic material can be avoided.

Various methods have been proposed for the non-magnetic one-component developing method. Among them, toner is passed between a developing sleeve and a charging member such as a blade pressed against the developing sleeve, and the toner is frictionally rubbed. A method of charging is general.

[0010] One of the serious image defects in electrophotography is fogging (a phenomenon in which toner adheres to a non-printed portion). Causes include charge leakage of the photoreceptor and improper setting of the apparatus (defective bias setting during reversal development).

Hitherto, various means for reducing fog have been studied. (1) By external addition method (2) By toner base composition (3) Dielectric loss tangent tan δ when toner is pelletized
Those that stipulate are proposed.

[0012] Among them, for example, in Japanese Patent No. 2596563, the range of tan δ is specified as tan δ.
Range of 5 to 5.0 * ^10-3 is to be good.

In Japanese Patent Application Laid-Open No. 8-305076,
Primarily in styrene-acrylic resin, the dielectric constant epsilon 'is 2.0 ≦ ε' ≦ 2.9,4.52 * 10 ^{over 3} ≦ tan [delta ≦
8.53 * 10 ^-3 is preferred.

[0014]

However, in the non-magnetic one-component developing method, which is a polyester-based resin used in recent years for improving the performance of toner and is often used for small-sized printers, only a conventional tan δ is used. According to the rule, fogging may occur, which is not sufficient. An object of the present invention is to provide a negatively charged non-magnetic one-component toner without fogging.

[0015]

The inventors of the present invention have conducted intensive studies and have found that a negatively charged non-magnetic one-component toner containing at least a polyester resin, a colorant, and inorganic fine particles has a dielectric constant ε ′ when an AC electric field is applied. And the dielectric loss tangent tanδ
However, it has been found that the negatively charged non-magnetic one-component toner satisfying the following formula (1) exhibits a good image with little fog.

[0016]

[Equation 2] (tan δ) <(− 4.5 * ¹⁰⁻³ ) * ε ′ + (22 * ¹⁰⁻³ ) (1)

That is, the present invention provides the following inventions. For a negatively charged non-magnetic one-component toner containing at least a polyester resin, a colorant, a charge control agent, and inorganic fine particles, a dielectric constant ε ′ when an AC electric field having a frequency of 1.5 kHz is applied.
And a dielectric loss tangent tan δ satisfying the following expression (1).

[0018]

[Equation 3] (tan δ) <(− 4.5 * ¹⁰⁻³ ) * ε ′ + (22 * ¹⁰⁻³ ) (1)

As the polyester resin used in the present invention, known and commonly used polyester resins can be used without any particular limitation.

Above all, a polyester resin which is appropriately cross-linked within a range that does not impair the pulverizability at the time of production and the low-temperature fixability in an actual machine has a mechanical strength capable of withstanding a share in a developing device. It can be suitably used as a resin for magnetic one-component toner.

The cross-linked polyester resin is, for example, a polycarboxylic acid having three or more valences or a derivative thereof,
Alternatively, it can be obtained by reacting a dicarboxylic acid or a dicarboxylic acid derivative with a diol using only a trihydric or higher polyhydric alcohol or a combination thereof. Here, the carboxylic acid derivative refers to a derivative capable of forming an ester with an alcohol, and examples thereof include a lower alkyl carboxylic acid ester and a carboxylic anhydride.

In the present invention, it is particularly preferable to use a polyester resin containing a cross-linked aromatic skeleton because the fog is reduced.

As the polyester resin, a thermoplastic crystalline aromatic polyester composed of an aromatic dicarboxylic acid, an aromatic diol or a derivative thereof is particularly preferred in terms of good blocking resistance. Among them,
More preferably, the aromatic polyester resin is a thermoplastic crystalline aromatic polyester having a skeleton composed of an ethylene oxide adduct of phthalic acid and bisphenol A.

The aromatic dicarboxylic acid used in the polyester resin used in the present invention includes, for example, phthalic anhydride, terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, and derivatives thereof.

Similarly, aromatic diols include:
Examples of the ethylene oxide adduct include polyoxyethylene- (2.0) -2,2-bis (4-hydroxyphenyl) propane and derivatives thereof, and examples of other aromatic diols include polyoxypropylene- (2 .
0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene- (2.2) -polyoxyethylene- (2.0) -2,2-bis (4-hydroxyphenyl) propane, poly Oxypropylene- (6)-
2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene- (2.2) -2,2-bis (4-
(Hydroxyphenyl) propane, polyoxypropylene- (2.4) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene- (3.3)-
Examples include 2,2-bis (4-hydroxyphenyl) propane and its derivatives.

As other components constituting the polyester according to the present invention, the following compounds can be used as required.

Examples of the dicarboxylic acid component include maleic acid, maleic anhydride, fumaric acid, itaconic acid, citraconic acid, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, cyclohexanedicarboxylic acid, succinic acid, malonic acid, glutaric acid, adipine Acids, azelaic acid, sebacic acid and the like. Examples of the trivalent or higher polyvalent carboxylic acid component include trimellitic acid, pyromellitic acid, and anhydrides thereof.

Other diol components that can be used to obtain the polyester resin in the present invention include:
For example, hydrogenated bisphenol A, ethylene glycol, diethylene glycol, triethylene glycol, 1,2
-Propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, cyclohexanedimethanol, and the like.

As the trihydric or higher polyhydric alcohol component,
For example, sorbitol, 1,2,3,6-hexanetetraol, 1,4-sorbitan, pentaerythritol,
1,2,4-butanetriol, 1,2,5-pentanetriol, glycerin, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3 ,
5-trimethylolbenzene and the like.

The polyester resin in the present invention can be obtained by performing a dehydration condensation reaction or a transesterification reaction using the above-mentioned raw material components in the presence of a catalyst.
The reaction temperature and reaction time at this time are not particularly limited, but are usually 100 to 300 ° C. and 30 minutes to 24 hours.

As a catalyst for carrying out the above reaction, for example, zinc oxide, stannous oxide, dibutyltin oxide, dibutyltin dilaurate and the like can be appropriately used.

The polyester resin used in the present invention only needs to have a glass transition point and a melt viscosity characteristic suitable for a non-magnetic one-component developing toner.
10 ⁵ While poise become temperature not less than 105 ° C. preferably has good fixability, inter alia, the viscosity of 1 × 10 ⁵
It is more preferable that the temperature at which poise is formed is 105 to 170 ° C., because the fixability at lower temperatures is good.

The glass transition point of the polyester resin may be any temperature at which the printer can be used normally, that is, at least room temperature, more preferably at least 40 ° C. in consideration of summertime, but preferably at least 57 ° C. Is more preferred. Further, those having a temperature of 57 to 83 ° C are particularly preferable.

Other constituents of the toner that can be used in the present invention include various auxiliaries such as a colorant, a charge controlling agent, and a release agent, and various auxiliaries can be selected and used depending on the purpose and conditions of use.

As the coloring agent that can be used in the present invention, well-known coloring agents can be mentioned. The black colorant is classified according to the production method, and examples thereof include carbon black such as furnace black, channel black, acetylene black, thermal black, and lamp black.

Examples of the chromatic colorant include conventionally known various organic pigments.

Examples of blue organic pigments include phthalocyanine C.I. I. Pigment Blue 15, 1
5: 1, 15: 2, 15: 3, 15: 4, 15: 6, indanthrone C.I. I. Pigment Blue 6
0 mag is raised.

Examples of the red organic pigment include quinacridone C.I. I. Pigment Red 122, an azo C.I. I. Pigment Red 22, 31, 4
8: 1, 48: 3, 53: 1, 57: 1, 112, 12
2, 149, 184, etc.

Examples of the yellow organic pigment include, for example, azo C.I. I. Pigment Yellow 12, 13, 1
4, 17, 81, 83, isoindolinone-based C.I. I.
Pigment Yellow 110, a benzimidazolone C.I. I. Pigment Yellow 15
1, C.I. I. Pigment Yellow 154,
C. I. Pigment Yellow 180, and the like.

The content of the colorant is preferably in the range of 1 to 20 parts by weight. More preferably, it is 2 to 10 parts by weight.

As the charge control agent used in the present invention, conventionally known, usually negative charge control agents can be used. Examples thereof include heavy metal-containing acidic dyes such as copper phthalocyanine, perylene, quinacridone, azo pigments, metal complex azo dyes, and azochrome complexes.

In the color toner, it is desirable to use a colorless charge control agent, such as salicylic acid or a metal complex compound of an ester of salicylic acid and an alkyl alcohol.

The toner of the present invention has negative chargeability. Depending on the degree of the negative chargeability of the binder resin, a charge control agent is selected so as to enhance the negative chargeability and improve the charge rising property, and to include a necessary amount thereof.

The content of the charge control agent in the present invention is preferably in the range of 0.05 to 8 parts by weight per 100 parts by weight of the polyester resin.

Further, in heat roll fixing applications, various waxes are used as necessary as an auxiliary agent for enhancing the releasing effect for the purpose of preventing troubles due to toner adhesion to the heat roll.

The wax is generally used in an amount of 0.1 to 10 parts by weight per 100 parts by weight of the binder resin.

Examples of the waxes include natural waxes such as montanic acid ester wax, high pressure polyethylene,
Polyolefin-based wax such as polypropylene Silicon-based wax, fluorine-based wax and the like can be used. Suitable waxes include, for example, Viscol 660P,
VISCOL 550P VISCOL 330P, TP-32
[Made by Sanyo Chemical Industries Ltd.], Mitsui High Wax NP5
05, P200, P300, and P400.

The production method for obtaining the toner of the present invention is as follows.
It can be obtained by known and commonly used means, for example, by melt-kneading a resin, a colorant and, if necessary, various additives at or above the melting point (softening point) of the resin, pulverizing and classifying. Can be done.

The coloring agent may be previously subjected to a flushing treatment so as to be uniformly dispersed in the resin, or a master batch melt-kneaded with the resin at a high concentration. Specifically, for example, the above-described resin and colorant are mixed as essential components by a kneading means such as a two-roll, three-roll, pressure kneader, or a twin-screw extruder. At this time, the colorant may be uniformly dispersed in the resin, and the conditions for melt-kneading are not particularly limited.
Minutes to 2 hours.

Then, after cooling, the mixture is finely pulverized by a pulverizer such as a jet mill and classified by an air classifier or the like. The average particle diameter of the toner particles is 3
~ 15 µm is preferred. Further, by externally adding inorganic fine particles, powder fluidity, charging stability, and the like can be further improved.

The non-magnetic one-component developing toner of the present invention includes:
External addition of inorganic fine particles is performed. As a fluidity improver, an inorganic fine particle powder can be used as a so-called external additive adhered to the toner surface.

As the inorganic fine particles in the present invention, conventionally known silicon dioxide, so-called silica, is preferably used. Among them, among the silicon dioxides, those having hydrophobicity and the like can be particularly preferably used. Examples of such an example include those obtained by subjecting silicon dioxide to a surface treatment with various polyorganosiloxanes, silane coupling agents, or the like.
For example, those commercially available under the following trade names can be suitably used.

AEROSIL R972, R974, R
202, R805, R812, RX200, RY20
0, RX50, NAX50, [Nippon Aerosil Co., Ltd.] WORKER HDK H2000, H2050EP
[Wacker Chemicals East Asia Co., Ltd.] Nipsil SS-10, SS-15, SS-20,
SS-50, SS-60, SS-100, SS-50
B, SS-50F, SS-10F, SS-40, SS-
70, SS-72F, [Nippon Silica Industry Co., Ltd.]

The amount of silica externally added is 0.1 to 100 parts by weight of toner particles in consideration of imparting a necessary charge amount to the toner, influence on the photosensitive drum, environmental characteristics of the toner, and the like.
~ 5.0 parts by weight is practically suitable.

In the non-magnetic one-component developing system, the external additive, which causes image deterioration during long-term continuous printing, is likely to be detached or buried in the toner surface. Two or more external additives having different particle sizes can be used in combination. Specifically, one is inorganic fine particles having an average particle diameter of 20 nm or less, and the other is inorganic fine particles having an average particle diameter of 30 nm or more. In this case, the former mainly works to secure liquidity, and the latter plays a role in preventing the former from being buried.

As the silica, there are silica having a relatively large average particle diameter and silica having a relatively small average particle diameter. These may be used alone, but in the present invention, different average particle diameters are used. It is preferable to use two types of silica in combination. The amounts of the two types of silica having different average particle sizes are each independently 0.1 parts by weight with respect to 100 parts by weight of the toner.
Preferably, it is used in the range of 5.0 to 5.0 parts by weight.

It is desirable to use organic fine particles in combination with the inorganic fine particles used in the present invention, since the charging becomes more stable. As the organic fine particles, conventionally known resin fine particles can be used, but benzoguanamine resin or polystyrene resin can maintain the charge of the toner at a high level, and has a greater effect of reducing fog. preferable.

As a method for externally adding the inorganic fine particles and the organic fine particles to the toner particles, for example, a conventional powder mixer such as a Henschel mixer or a so-called surface modifier such as a hybridizer is used. Can be.

The toner of the present invention is used in a non-magnetic one-component developing method. As the non-magnetic one-component developing method, a known and commonly used method can be employed. For example, the toner conveyed by the toner carrier is frictionally charged by a layer thickness regulating member and the layer thickness is regulated, and the toner is conveyed on the carrier. Into thin layers,
There is a method of developing an electrostatic latent image by contacting or non-contacting the electrostatic latent image carrier.

In the present invention, the layer thickness regulating member needs to be a metal capable of frictionally charging the developer when passing through a gap with a developer carrier described later. Examples of the type of metal include aluminum, duralumin, copper,
Stainless steel and the like can be mentioned, and among them, stainless steel is preferable because it has both good durability and charge-imparting property.

The toner of the present invention can be fixed on a recording medium by a known and common fixing method, but exhibits more excellent performance in a pressure fixing type printer using a heat roll. In this case, as the heat roll, a roll having a heat resistance and excellent releasability, preferably, whose outermost layer is made of a fluororesin or a silicone resin can be used. The fixing temperature is not particularly limited, but the heat roll on the side in contact with the unfixed image is usually set to 150 to 250 ° C.

In the present invention, for measuring ε ′ and tan δ, any measuring device having a conventionally known bridge circuit as a measuring principle circuit can be used without particular limitation.

In general, the tan δ of a powder is affected by the packing density of the powder. In order to eliminate such an effect, it is common to apply pressure to the powder and use the pelletized material as a sample.

In the present invention, the pressure of 2550 kgf / cm ² is applied to a 5
A pellet having a diameter of 0φ and a thickness of 4 to 6 mm was prepared, and a frequency of 1.10 was measured by a measuring device (4284A: manufactured by Hewlett-Packard Company).
After applying an AC electric field of 5 kHz, tan δ and dielectric constant ε ′ are measured 10 seconds later.

[0065]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described based on preferred embodiments. Acid value 3 ~ including bisphenol skeleton
12, average particle diameter including a crosslinked polyester resin having a Tg of 65 to 73 ° C. and a melt viscosity of 1 × 10 ⁵ poise at a temperature of 160 to 166 ° C., a colorant, a negative charge control agent, and a polyolefin wax To a negatively charged base toner powder of 3 to 8 microns, a hydrophobic silica fine powder having an average particle diameter of 20 nm or less and a hydrophobic silica fine powder having an average particle diameter of 30 nm or more are added, and an AC electric field having a frequency of 1.5 kHz is applied. The negatively-charged toner having the dielectric constant ε ′ and the dielectric loss tangent tan δ satisfying the expression (1) is obtained.

The toner conveyed by the toner carrier is negatively triboelectrically charged and regulated in thickness by a layer thickness regulating member (charging blade) made of stainless steel, and is thinned on the carrier. The electrostatic latent image is developed by a non-magnetic one-component developing method for developing the electrostatic latent image by contacting or non-contacting with the electrostatic latent image carrier (developing sleeve) made of conductive rubber, and transferring the image onto a recording medium. The image is fixed by pressure fixing.

[0067]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples. An example of the synthesis of the polyester resin used for preparing the toner first is shown below. Hereinafter, parts and% are based on weight. The following example embodies the preferred embodiment described above.

Example 1 (Resin Synthesis Example 1) 68 mol parts of bisphenol A, 16 mol parts of terephthalic acid, 10 mol parts of trimellitic anhydride, 5 mol parts of ethylene glycol and 0.1 mol of dibutyltin oxide.
06 mol part was charged in a flask, and the temperature was 220 ° C.
For about 20 hours to synthesize a polyester resin. The resin synthesized in this manner is referred to as “resin A”.

The obtained polyester resin has an acid value of 10,
The temperature at which the melt viscosity reached 1 × 10 ⁵ poise was 164 ° C., and the glass transition temperature (Tg) was 70 ° C.

(Mixing Step 1) Resin A 92 parts by weight Carbon black Mogal L (manufactured by Cabot Specialty Chemicals, Inc.) 5 parts by weight Charge control agent Bontron S34 (manufactured by Orient Chemical Industry Co., Ltd.) 1 part by weight Wax Biscol 550P 2 parts by weight (manufactured by Sanyo Chemical Industries, Ltd.) are mixed with a Henschel mixer.

(Kneading Step) The above mixture is kneaded with a twin-screw kneader.

Thereafter, the resultant is finely pulverized and classified to obtain a toner powder A.

(Mixing Step 2) Toner A is obtained by mixing 100 parts by weight of toner powder A, 1 part by weight of silica NAX50, and 1 part by weight of silica R972 with a Henschel mixer and then sieving.

Example 2 (Resin Synthesis Example 2) A flask was charged with 68 mol parts of bisphenol A, 16 mol parts of terephthalic acid, 10 mol parts of trimethylolpropane, 5 mol parts of ethylene glycol and 0.06 parts of dibutyltin oxide. Atmosphere 22
The reaction was carried out at 0 ° C. for about 20 hours to synthesize a polyester resin. The resin synthesized in this manner is referred to as “resin B”.

The obtained polyester resin had an acid value of 5, a melt viscosity of 1 × 10 ⁵ poise, a temperature of 162 ° C., and a glass transition temperature (Tg) of 68 ° C.

(Mixing Step 3) Resin B 92 parts by weight Carbon black Mogal L (manufactured by Cabot Specialty Chemicals, Inc.) 5 parts by weight Charge control agent Bontron S34 (manufactured by Orient Chemical Industry Co., Ltd.) 1 part by weight Wax Biscol 550P 2 parts by weight (manufactured by Sanyo Chemical Industries, Ltd.) are mixed with a Henschel mixer.

(Kneading Step) The above mixture is kneaded with a twin-screw kneader.

Thereafter, the resultant is finely pulverized and classified to obtain a toner powder B.

(Mixing Step 2) Toner B is obtained by mixing 100 parts by weight of toner powder B, 1 part by weight of silica NAX50, and 1 part by weight of silica R972 with a Henschel mixer and then sieving.

Example 3 In the mixing step 2 of Example 1, NAX50, R972
Toner C was obtained in the same manner as in Example 1, except that benzoguanamine resin (Eposter S) was added in an amount of 0.5 part by weight.

Comparative Example 1 Toner D was prepared in the same manner as in Example 1 except that Ketjen Black was used in place of Carbon Mottle L.
Got

Comparative Example 2 A toner E was obtained in the same manner as in Example 1 except that the resin amount was changed to 90 parts by weight and the carbon amount was changed to 7 parts by weight.

Comparative Example 3 Toner F was obtained in the same manner as in Example 1 except that Ketjen Black was used instead of Carbon Mocar L in Example 2.

Comparative Example 4 A toner G was obtained in the same manner as in Example 1 except that the amount of resin was changed to 90 parts by weight and the amount of carbon was changed to 7 parts by weight.

The dielectric constant ε ′ and tan δ of the toner were measured. The results are described below. The calculation result on the right side of Equation 1 is also described below.

[0086]

[Table 1]

Evaluation 2 New N-methyl-2-pyrrolidone (manufactured by BASF) 1
A 00% washing solution was prepared.

The cleaning solution was heated to 60 ° C., and an aluminum drum (diameter 30 mm; hereinafter, referred to as a conductive substrate) whose surface was cut into a mirror surface was immersed in the cleaning solution, and an ultrasonic oscillator (600 W, 28 kHz) was used. ) For 3 minutes.

Next, the conductive substrate is immersed in a bath to which 26 ° C. pure water (0.5 μS / cm) is continuously supplied, and an ultrasonic cleaner (PT-06B manufactured by Pretec Co., Ltd .; output 300 W).
And treated for 3 minutes while applying ultrasonic waves while constantly changing the frequency in the range of 37.5 ± 2 kHz.

Further, the washed conductive substrate was immersed in a liquid tank to which pure water at 70 ° C. was continuously supplied, allowed to stand for 15 seconds, and then pulled up at a speed of 7 mm / second.

Next, a solution prepared by dissolving 7 parts of copolymerized nylon (trade name “CM-8000” manufactured by Toray Industries, Inc.) in 60 parts of methanol and 40 parts of n-butanol was applied onto the obtained conductive substrate. The coating was applied by dipping so that the film thickness after drying was 1 μm, and then dried to form an intermediate layer.

Crystals obtained by synthesizing titanyl phthalocyanine and recrystallizing from a concentrated sulfuric acid solution were pulverized by an attritor mill at 90 ° C. for 90 minutes. 5 parts of butyral resin (trade name “ESLEC BL-1”) Chemical company)
5 parts and 90 parts of methylene chloride were mixed and dispersed using a vibration mill to obtain a coating for a charge generation layer. This paint has a thickness of 0.3 μm after being dried on the intermediate layer by the dipping method.
And then dried to form a charge generation layer.

Next, 9 parts of a hydrazone compound represented by the following formula and 10 parts of polycarbonate (trade name "Iupilon Z200" manufactured by Mitsubishi Gas Chemical Co., Ltd.) as a binder resin, 60 parts of methylene chloride and 20 parts of monochlorobenzene 20 Using a solution dissolved in a mixed solvent consisting of parts, the solution was coated on the charge generation layer by a dipping method so that the film thickness after drying was 20 μm, and then dried to form a charge transport layer. A photoreceptor was obtained.

[0094]

Embedded image

The developing sleeve having the following specifications was prepared.

Material: conductive silicon rubber Surface resistance: 5.47 * 10 ⁶ Ω Rubber hardness: 60 degrees (Shore A)

A metal plate of SUS304 was prepared as a charging blade.

The above-mentioned photoreceptor, developing sleeve and charging blade were mounted on the following non-magnetic one-component printer, and printing evaluation of various toners was performed.

Charging method of photoreceptor: Contact charging by nylon brush Exposure light source: 780 nm laser Charging method of toner: Friction charging with SUS304 and silicon rubber Toner developing method: Contact method Printing speed: 2100 mm / min

[0100]

[Table 2]

The toner of Example 3 was more excellent in charge stability than the toner of Example 1.

[0102]

According to the present invention, at least a polyester resin, a colorant and inorganic fine particles are contained, and the dielectric constant ε ′
And the dielectric loss tangent tan δ, the toner is configured so as to satisfy a specific expression, so that in the non-magnetic one-component developing method, a particularly remarkable effect that a good image with little fog can be obtained can be obtained.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H005 AA01 AA06 AA08 CA03 CA08 CA15 CB13 DA02 EA01 EA05 FA07

Claims (3)

[Claims] 1. A negatively-charged non-magnetic one-component toner containing at least a polyester resin, a colorant, a charge control agent, and inorganic fine particles, has a dielectric constant ε ′ and a dielectric loss tangent tan δ when an AC electric field of a frequency of 1.5 kHz is applied. Is given by the following equation (1)
A negatively charged non-magnetic one-component electrostatic charge developing toner, characterized by satisfying the following. [Equation 1] (tan δ) <(− 4.5 * ¹⁰⁻³ ) * ε ′ + (22 * ¹⁰⁻³ ) (1) 2. The inorganic fine particles are two types of hydrophobic silica fine powders having different average particle sizes, and the fine particles have an average particle size of 20.
2. The negatively-charged non-magnetic one-component electrostatic charge developing toner according to claim 1, wherein the toner is of two types: nm or less and 30 nm or more. 3. The toner according to claim 2, wherein the organic fine particles are benzoguanamine resin particles or polystyrene resin particles.