JP3372698B2 - Toner and image forming method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner used in a recording method using an electrophotographic method, an electrostatic recording method, etc., and an image forming method. More specifically, the present invention relates to a toner and an image forming method used in a copying machine, a printer, and a fax, in which a toner image is previously formed on an electrostatic latent image carrier and then transferred onto a transfer material to form an image.

[0002]

2. Description of the Related Art Conventionally, a large number of electrophotographic methods are known, but generally, a photoconductive substance is used and an electric latent image is formed on an image bearing member (photoreceptor) by various means. After forming the latent image, the latent image is developed with toner to form a visible image, and the toner image is transferred to a transfer material such as paper as necessary, and then the toner image is fixed on the transfer material by heat or pressure. To obtain a copy.

As a method for visualizing an electric latent image, a cascade developing method, a magnetic brush developing method, a pressure developing method and the like are known. Further, there is also used a method in which a magnetic toner is used and a rotating sleeve having a magnetic pole at the center is used to fly between the photosensitive member and the sleeve by an electric field.

Unlike the two-component system, the one-component developing system does not require carrier particles such as glass beads and iron powder, so that the developing device itself can be made compact and lightweight. Further, since the two-component developing system needs to keep the toner concentration in the carrier constant, a device for detecting the toner concentration and supplying a required amount of toner is required. Therefore, also in this case, the developing device becomes large and heavy. Such a device is not necessary in the one-component developing system, and it is preferable because it can be made small and light.

In addition, LED and LBP printers have become the mainstream of the market in recent years as the printer apparatus, and the direction of technology is higher resolution, that is, 400, 600, 800 dpi instead of 240, 300 dpi in the past. ing. Therefore, the developing system is also required to have higher definition. Further, the copiers are also becoming more sophisticated, and as a result, they are moving toward digitalization. In this direction, the method of forming an electrostatic charge image by a laser is mainly used, and therefore, it is also advancing toward high resolution, and here also, as in the case of a printer, a high resolution / high definition developing method is required. . For this reason, the particle size of the toner is being reduced, and it is disclosed in Japanese Patent Laid-Open Nos. 1-112253 and 1-1.
No. 91156, No. 2-214156, No. 2-284158, No. 3-181952.
Japanese Patent Application Laid-Open No. 4-162048 and Japanese Patent Application Laid-Open No. 4-162048 propose a toner having a specific particle size distribution and a small particle size.

The toner image formed on the photoconductor in the developing process is transferred to the transfer material in the transfer process, but the transfer residual toner remaining on the photoconductor is cleaned in the cleaning process.
Toner is stored in the waste toner container. For this cleaning process, blade cleaning, fur brush cleaning, roller cleaning, etc. have been conventionally used. From the viewpoint of the apparatus, the size of the apparatus is inevitably increased due to the provision of such a cleaning apparatus, which has been a bottleneck when aiming to make the apparatus compact. Further, from the viewpoint of ecology, a system with less waste toner is desired in terms of effective utilization of toner, and a toner with good transfer efficiency has been demanded.

Japanese Patent Application Laid-Open No. 61-279864 proposes toners having shape factors SF-1 and SF-2. However, there is no description regarding transfer in this publication, and as a result of carrying out Examples, transfer efficiency is low and further improvement is required.

Further, Japanese Patent Application Laid-Open No. 63-235953 proposes a magnetic toner spherically shaped by a mechanical impact force. However, the transfer efficiency is still insufficient and further improvement is needed.

Further, in recent years, from the viewpoint of environmental protection, the primary charging and transfer processes using corona discharge, which have been conventionally used, are becoming mainstream, and the primary charging and transfer processes using a photoconductor contact member are becoming mainstream.

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 latent image carrier,
While electrostatically charging the electrostatic latent image carrier while applying a voltage to the conductive roller, another voltage was applied to the electrostatic latent image carrier after obtaining a toner image by exposure and development steps. While transferring the transfer material while pressing the conductive roller to transfer the toner image on the electrostatic latent image bearing member onto the transfer material, a transfer image is obtained through a fixing step.

However, in such a roller transfer system which does not use corona discharge, the transfer member is brought into contact with the photoconductor through the transfer member during the transfer, so that the toner image formed on the photoconductor is transferred to the transfer material. When the toner image is transferred to the toner image, the toner image is pressed into contact with the toner image, which causes a problem of partial transfer failure, which is so-called transfer void (see FIG. 5).

Further, in the roller charging system, the physical and chemical action on the surface of the electrostatic latent image bearing member due to the discharge generated between the charging roller and the electrostatic latent image bearing member is larger than that in the corona charging system. In particular, in the combination with the organic photoconductor / blade cleaning, abrasion due to deterioration of the photoconductor surface is likely to occur, and there is a problem in life (direct charging /
The combination of the organic photoreceptor / one-component magnetic developing method / contact transfer / blade cleaning makes it easy to reduce the cost and size and weight of the image forming apparatus. This is the mainstream method for printers, facsimiles, etc. ).

Therefore, it has been required that the toner and the photoreceptor used in such an image forming method have excellent releasability.

[0014]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a toner and an image forming method which solve the above problems of the prior art.

That is, the object of the present invention is to provide excellent transferability,
An object of the present invention is to provide a toner and an image forming method in which the amount of residual toner after transfer is small and voids in transfer do not occur even in a roller transfer system, or these phenomena are suppressed.

Further, an object of the present invention is to provide a toner and an image forming material which are excellent in releasability and slidability, and which have a long life and a small photoconductor abrasion after these functions, even after printing for a long period of time and after printing a large number of sheets. To provide a method.

A further object of the present invention is to provide a toner and an image forming method in which abnormal charging or image defects due to contamination of a member pressed against an electrostatic latent image carrier does not occur, or these phenomena are suppressed. It is in.

[0018]

The present invention is a toner having at least toner particles in which a colorant is dispersed in a binder resin and an inorganic fine powder, and the shape factor of the toner measured by an image analyzer. The value of SF-1 is 120 ≦ SF-1
≦ 160 and the value of the shape factor SF-2 is 115 ≦ SF.
−2 ≦ 140, and the ratio B / of the value B obtained by subtracting 100 from the value of SF-2 and the value A obtained by subtracting 100 from the value of SF-1
The value of A is 0.35 to 0.85 or less, and B of the toner is
Specific surface area S per unit volume measured by ET method
b (m ² / cm ³ ) and the specific surface area St per unit volume calculated from the weight average particle diameter when the toner is assumed to be a true sphere
The relationship of (m ² / cm ³ ) satisfies the following conditions 3.0 ≦ Sb / St ≦ 7.0 Sb ≧ St × 1.5 + 1.5, and the specific surface area Sb is 3.2 to 6.8 (m ² / c
m ³ ).

In the present invention, a developing step of developing an electrostatic latent image to form a toner image on an electrostatic latent image carrier, and a step of bringing the toner image into contact with a transfer member to which a voltage is applied In the image forming method using an electrophotographic apparatus having a contact transfer step of transferring onto a transfer material while being carried out, the toner is a toner having at least toner particles in which a colorant is dispersed in a binder resin and inorganic fine powder. , The value of the shape factor SF-1 measured by the image analyzer of the toner is 120 ≦ SF−
1 ≦ 160 and the value of the shape factor SF-2 is 115 ≦ S
F-2 ≦ 140, the ratio B of the value B obtained by subtracting 100 from the value of SF-2 and the value A obtained by subtracting 100 from the value of SF-1
The value of / A is 0.35 to 0.85 or less, the specific surface area Sb (m ² / cm ³ ) per unit volume of the toner measured by the BET method, and the toner when assuming that the toner is a true sphere. Specific surface area St per unit volume calculated from the weight average particle diameter
The relationship of (m ² / cm ³ ) satisfies the following conditions 3.0 ≦ Sb / St ≦ 7.0 Sb ≧ St × 1.5 + 1.5, and the specific surface area Sb is 3.2 to 6.8 (m ² / c
m ³ ) in the image forming method.

In the present invention, SF-indicating the shape factor
1 and SF-2 are, for example, Hitachi FE-SEM
(S-800) is used to randomly sample 100 toner images of 2 μm or more magnified 1000 times, and the image information is introduced into an image analysis device (Luzex III) manufactured by Nicolet Co., Ltd. through an interface. The value obtained by performing the analysis and calculating from the following equation is used as the shape factor SF-1, S
It is defined as F-2.

[0021]

[Equation 1]

(Where MXLNG is the absolute maximum length of the particle,
PERIME represents the perimeter of the particle, and AREA represents the projected area of the particle. )

The shape factor SF-1 indicates the degree of roundness of the toner particles, and the shape factor SF-2 indicates the degree of unevenness of the toner particles.

When the toner shape factor SF-1 is 110 or less, the toner spherical factor SF-2 is 110 or less, and the ratio B / A is more than 1.0, cleaning failure generally occurs. It is easy to do, and the toner shape factor S
When F-1 exceeds 180, the toner is separated from the sphere and approaches an irregular shape, the toner is easily crushed in the developing device, the particle size distribution is fluctuated, the charge amount distribution is apt to be broad, and background fog and reverse fog occur. Cheap. On the other hand, if SF-2 exceeds 140, the transfer efficiency of the toner image at the time of transfer from the electrostatic image carrier to the transfer material is deteriorated, and character or line image dropout occurs, which is not preferable. At this time, the toner manufactured by the pulverization method is preferably used. As mentioned above, SF-1 is preferably 120 to 160 and SF-2 is 11
5 to 140 and the ratio B / A is 0.35 to 0.85.
Is.

The value of the ratio B / A shows the slope of a straight line passing through the origin in FIG. 6, and this value is 0.35 to 0.85.
Is preferable in order to improve transferability while maintaining developability.

Further, by having the inorganic fine powder on the surface of the toner particles, the transfer efficiency is improved and the voids in the transfer of characters and line images are improved. At this time, the specific surface area Sb per unit volume measured by the BET method and the specific surface area St per unit volume (St = 6 / calculated from the weight average particle diameter (D ₄ ) assuming that the toner is a true sphere. D ₄ ) is 3.0 ≦ Sb / St ≦ 7.0 and Sb ≧ St ×
It is preferably 1.5 + 1.5, and further, Sb is 3.2 to 6.8 m ² / cm ³ (more preferably 3.4 to
It is preferably 6.3 m ² / cm ³ ).

If the ratio is less than 3.0 times, the transfer efficiency is insufficient, and if it exceeds 7.0 times, the image density decreases. It is considered that this is because the inorganic fine particles added to the toner particles behave effectively as a spacer between the toner particles and the toner image carrier.

The specific surface area of the toner within the above range can be achieved by controlling the specific surface area of the toner particles, the specific surface area of the inorganic fine powder added to the toner particles, the addition amount and the addition mixing strength. If the addition and mixing strength is too high, the inorganic fine particles will be embedded in the toner particles and the transfer efficiency will not be improved sufficiently.

Furthermore, since the inorganic fine powder is effectively used, the specific surface area Sr per volume of the toner particles is 1.2 to
2.5m ² / cm ³ (preferably 1.4~2.1m ² / c
m ³ ), which is 1.5 to the theoretical specific surface area per volume calculated from the weight average particle diameter assuming that the toner is a true sphere.
It is good to be 2.5 times.

The specific surface area is preferably increased by 1.5 m ² / cm ³ or more by adding the inorganic fine powder. 1 nm to 100 nm of toner particles before adding inorganic particles
The 60% pore radius in the cumulative pore area ratio curve of the pores is preferably 3.5 nm or less. At this time, the BET specific surface area Sb of the toner and the BET specific surface area Sr of the toner particles
The value of the ratio Sb / Sr of is preferably in the range of 2-5.

These are those in which the inorganic fine powder behaves more effectively and the transfer efficiency is improved by reducing the pores in the toner particles which are larger than the primary particle diameter of the inorganic fine powder added to the toner particles. it is conceivable that.

The specific surface area was determined according to the BET method by using a specific surface area measuring device Autosorb 1 (manufactured by Yuasa Ionics Co., Ltd.) to adsorb nitrogen gas on the sample surface and calculating the specific surface area using the BET multipoint method. Further, the 60% pore radius was calculated from the integrated pore area ratio curve with respect to the desorption side pore radius. In Autosorb 1, the pore size distribution is calculated by Bar
rett, Joyner & Harenda (B.
J. H.). J. The H method is used.

In order to faithfully develop finer latent image dots for higher image quality, the toner particles have a weight average diameter of 4
The thickness is preferably 9 to 9 μm. Weight average diameter is 4μ
With toner particles of less than m, a large amount of toner remains after being transferred on the photoconductor due to a decrease in transfer efficiency, and moreover, it is likely to cause uneven image unevenness due to fog and transfer failure. Not preferable. Further, when the weight average diameter of the toner particles exceeds 9 μm, scattering of characters and line images is likely to occur.

For the average particle size and particle size distribution of the toner, Coulter Counter TA-II type or Coulter Multisizer (manufactured by Coulter Co.) is used, and an interface (manufactured by Nikkaki Co., Ltd.) for outputting number distribution and volume distribution and PC9.
801 personal computer (manufactured by NEC) is connected, and the electrolyte is 1% NaCl using primary sodium chloride.
Prepare an aqueous solution. For example, ISOTON R-II
(Manufactured by Coulter Scientific Japan) can be used. As the measuring method, the electrolytic aqueous solution 100 to 1 is used.
0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) as a dispersant is added to 50 ml,
Further, 2 to 20 mg of the measurement sample is added. The electrolytic solution in which the sample was suspended was subjected to dispersion treatment for about 1 to 3 minutes by an ultrasonic disperser, and the volume and number of toner particles having a size of 2 μm or more were measured using a 100 μm aperture as an aperture with the Coulter Counter TA-II type. The volume distribution and number distribution were calculated. Then, the volume-based weight average particle diameter (D ₄ ) obtained from the volume distribution and the number-based length average particle diameter (D ₁ ) obtained from the number distribution according to the present invention were obtained.

Further, the charge amount per unit volume (two-component method) of the toner according to the present invention is 30 to 80 C / m ³ (more preferably 40 to 70 C / m ³ ). It is preferable for improving transfer efficiency in a transfer method using a member.

The method for measuring the charge amount (two-component tribo) of the toner in the present invention by the two-component method is shown below (FIG. 4).

In an environment of 23 ° C. and relative humidity of 60%, EFV200 / 300 (manufactured by Powdertech Co., Ltd.) was used as a carrier, and a mixture of 9.5 g of carrier and 0.5 g of toner was added to a polyethylene bottle having a capacity of 50 to 100 ml. Shake by hand 50 times. Next, 1.0 to 1.2 g of the mixture is put into a metal measuring container 22 having a 500-mesh screen 23 on the bottom, and a metal lid 24 is placed. At this time, the total mass of the measurement container 22 is weighed and set as W ₁ (g). Next, in the suction device (at least the portion in contact with the measurement container 22 is an insulator), suction is performed from the suction port 27 and the air flow rate control valve 26 is adjusted to adjust the pressure of the vacuum gauge 25 to 2450 Pa (25
0 mmAq). In this state, suction is performed for 1 minute to remove the toner by suction. The potential of the electrometer 29 at this time is V
(Bolt). Here, 28 is a capacitor, and the capacitance is C (μF). Further, the mass of the entire measuring machine after suction is weighed and designated as W ₂ (g). Triboelectric charge amount of this toner (m
C / kg) is calculated by the following formula.

Triboelectric charge amount (mC / kg) = CV / (W ₁ -W ₂ ).

The binder resin used in the toner according to the present invention has a low molecular weight peak in the range of 3,000 to 15,000 in the GPC molecular weight distribution, and the shape of the toner produced by the pulverization method is thermomechanical. It is preferable for controlling with impact force. Low molecular weight peak is 1
When it exceeds 5,000, it is difficult to control the shape factors SF-1 and SF-2 within the range of the present invention, and the transfer efficiency is not sufficiently improved. On the other hand, if it is less than 3000, fusion tends to occur during surface treatment. The molecular weight is measured by GPC (gel permeation chromatography). Specific GPC
As a measuring method, a sample obtained by previously extracting the toner with a Soxhlet extractor for 20 hours with a THF (tetrahydrofuran) solvent was used, and the column configuration was Showa Denko A
-801, 802, 803, 804, 805, 806
The molecular weight distribution can be measured by connecting 807 and using a calibration curve of a standard polystyrene resin.

A resin having a weight average molecular weight (Mw) to number average molecular weight (Mn) ratio (Mw / Mn) of 2 to 100 is preferable for the present invention.

The glass transition point Tg of the toner is preferably 50 ° C. to 75 ° C. (more preferably 52 ° C. to 70 ° C.) from the viewpoint of fixability and storability.

Glass transition point Tg of the toner according to the present invention
For example, DSC- manufactured by Perkin Elmer Co., Ltd.
The measurement is performed with a highly accurate internal heat input compensation type differential scanning calorimeter such as 7. The measuring method is ASTM D3418-8.
Perform according to 2. In the present invention, the material is heated once to take a previous history, then rapidly cooled, and then again at a temperature rate of 10 ° C./m.
In, a DSC curve measured when the temperature is raised in the range of 0 to 200 ° C. is used.

The type of the binder resin used in the present invention is, for example, a homopolymer of styrene such as polystyrene, poly-p-chlorostyrene, polyvinyltoluene and the like, or a substitution product thereof; styrene-p-chlorostyrene copolymerization. Coal, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene- Acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile- Styrene-based copolymers such as indene copolymers Combined; polyvinyl chloride, phenol resin, natural 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 resin and the like can be used. A crosslinked styrene resin is also a preferable binder resin.

Examples of the comonomer for the styrene monomer of the styrene type copolymer include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate,
Didecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, etc. A monocarboxylic acid having a heavy 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 the like; and substituted compounds thereof; for example, vinyl chloride,
Vinyl esters such as vinyl acetate, vinyl benzoate, etc., ethylene-based olefins such as ethylene, propylene, butylene, etc .; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, etc .;
For example, vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether and the like; and vinyl monomers such as are used alone or in combination. Here, as the cross-linking agent, a compound having two or more polymerizable double bonds is mainly used, and examples thereof include aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; for example, ethylene glycol diacrylate and ethylene glycol. Dimethacrylate,
A carboxylic acid ester having two double bonds such as 1,3-butanediol dimethacrylate; a divinyl compound such as divinylaniline, divinyl ether, divinyl sulfide, divinyl sulfone; and a compound having three or more vinyl groups; Can be used alone or as a mixture.

As the binder resin for toner used for pressure fixing, low molecular weight polyethylene, low molecular weight polypropylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer, higher fatty acid, polyamide Resin and polyester resin may be used. These are preferably used alone or in combination.

Further, it is also preferable to include the following waxes in the toner from the viewpoint of improving the releasability from the fixing member during fixing and the fixing property. Paraffin wax and its derivatives, microcrystalline wax and its derivatives, Fischer-Tropsch wax and its derivatives, polyolefin wax and its derivatives, carnauba wax and its derivatives, etc., where the derivatives are oxides and block copolymers with vinyl monomers. , Including graft modified products.

In addition, alcohols, fatty acids, acid amides,
Esters, ketones, hydrogenated castor oil and its derivatives, plant wax, animal wax, mineral wax, petrolactam and the like can also be used.

In the magnetic toner of the present invention, a charge control agent is blended with toner particles (internal addition) or mixed with toner particles (external addition).
It is preferable to use. The charge control agent makes it possible to control the optimum charge amount according to the developing system, and particularly in the present invention, the balance between the particle size distribution and the charge amount can be further stabilized. The following substances control 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 type metal complexes. Other examples include aromatic hydroxycarboxylic acids, aromatic mono- and polycarboxylic acids and their metal salts, anhydrides, esters, and phenol derivatives such as bisphenol.

Further, there are the following substances for controlling the positive charge property.

Modified products of nigrosine and fatty acid metal salts and the like; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, and phosphonium salts which are analogs thereof. Onium salts and lake pigments thereof, triphenylmethane dyes and lake pigments thereof (as a laker, phosphotungstic acid, phosphomolybdic acid, phosphotungstic molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide) Compounds, ferrocyanides, etc.), metal salts of higher fatty acids; diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide; dibutyltin borate, dioctyltin borate, dicyclohexyl Diorgano tin borate such as Suzuboreto; can be used in combination singly or two or more kinds.

The above charge control agents are preferably used in the form of fine particles, and in this case, the number average particle diameter of these charge control agents is preferably 4 μm or less, more preferably 3 μm or less. When these charge control agents are internally added to the toner, it is preferable to use 0.1 to 20 parts by mass, particularly 0.2 to 10 parts by mass with respect to 100 parts by mass of the binder resin.

As the colorant used in the present invention, carbon black, a magnetic material, or a yellow / magenta / cyan colorant shown below, which is toned black, is used.

As the yellow colorant, condensed azo compounds, isoindolinone compounds, anthraquinone compounds,
Compounds represented by azo metal complexes, methine compounds and allylamide compounds are used. Specifically, C.I. I. Pigment Yellow 12, 13, 14, 15, 17, 6
2, 74, 83, 93, 94, 95, 97, 109, 1
10, 111, 120, 127, 128, 129, 14
7, 168, 174, 176, 180, 181, 191
Etc. are preferably used.

As the magenta colorant, a condensed azo compound, a diketopyrrolopyrrole compound, an anthraquinone, a quinacridone compound, a basic dye lake compound, a naphthol compound, a benzimidazolone compound, a thioindigo compound, and a perylene compound are used. Specifically, C.I.
I. Pigment Red 2, 3, 5, 6, 7, 23, 4
8; 2, 48; 3, 48; 4, 57; 1, 81; 1, 1
44, 146, 166, 169, 177, 184, 18
5,202,206,220,221,254 are particularly preferred.

As the cyan colorant, a copper phthalocyanine compound and its derivative, an anthraquinone compound, a basic dye lake compound and the like can be used. Specifically, C.I. I.
Pigment Blue 1, 7, 15, 15: 1, 15: 2,
15: 3, 15: 4, 60, 62, 66 and the like can be used particularly preferably.

These colorants can be used alone or in combination, and can be used in the form of solid solution. The colorant of the present invention is selected in terms of hue angle, saturation, lightness, weather resistance, OHP transparency, and dispersibility in the toner. The amount of the colorant added is 1 to 20 parts by mass based on 100 parts by mass of the resin.

When a magnetic substance is used as the black colorant, unlike other colorants, the amount is 30 with respect to 100 parts by mass of the resin.
It is used by adding up to 200 parts by mass.

Examples of magnetic materials include metal oxides containing elements such as iron, cobalt, nickel, copper, magnesium, manganese, aluminum and silicon. Of these, those containing iron oxide as a main component, such as ferrosoferric oxide and γ-iron oxide, are preferable. Further, from the viewpoint of controlling the toner chargeability, other metal elements such as silicon element or aluminum element may be contained. These magnetic particles are B-based by the nitrogen adsorption method.
ET specific surface area is preferably 2 to 3 m ² / g, especially 3 to 28
A magnetic powder having m ² / g and a Mohs hardness of 5 to 7 is preferable.

The shape of the magnetic material is octahedron, hexahedron,
There are spheres, needles, scales, etc., but those having little anisotropy such as octahedrons, hexahedrons, spheres, and irregular shapes are preferable for increasing the image density. The average particle size of the magnetic substance is 0.05 to
1.0 μm is preferable, and 0.1 to 0.
6 μm, and more preferably 0.1 to 0.4 μm.

The amount of magnetic material is 3 with respect to 100 parts by mass of the binder resin.
0 to 200 parts by mass, preferably 40 to 200 parts by mass, and more preferably 50 to 150 parts by mass. If the amount is less than 30 parts by mass, in a developing device that uses magnetic force for toner transportation, the transportability is insufficient, and unevenness in the developer layer on the developer carrier tends to result in image unevenness. The image density tends to decrease due to the above. On the other hand, if the amount exceeds 200 parts by mass, the fixing property tends to have a problem.

As the inorganic fine powder contained in the toner of the present invention, known ones can be used. To improve the charge stability, developability, fluidity and storability, silica, alumina,
It is preferably selected from titania and its complex oxides. Furthermore, silica is more preferable. For example, as the silica, both a so-called dry method produced by vapor phase oxidation of a silicon halide or an alkoxide or a dry silica called fumed silica and a so-called wet silica produced from alkoxide, water glass, etc. can be used. However, dry silica having less silanol groups on the surface and inside the fine silica powder and less production residues such as Na ₂ O and SO ₃ ²⁻ is preferable. Further, in the case of dry silica, it is also possible to obtain a composite fine powder of silica and other metal oxide by using other metal halogen compound such as aluminum chloride and titanium chloride together with the silicon halogen compound in the manufacturing process. Also includes.

[0063] Inorganic fine powder used in the present invention is the specific surface area by nitrogen adsorption measured by BET method is 30 m ² / g or more, particularly given good results in the range of 50 to 400 m ² / g, the toner 100 mass It is particularly preferable to use 0.1 to 8 parts by mass of fine silica powder, preferably 0.5 to 5 parts by mass, more preferably more than 1.0 and up to 3.0 parts by mass per part.

The inorganic fine powder used in the present invention is
The primary particle size is preferably 30 nm or less.

The inorganic fine powder used in the present invention is
Silicone varnishes, various modified silicone varnishes, silicone oils, various modified silicone oils, silane coupling agents, silane coupling agents having functional groups, other organic silicon compounds, organics for the purpose of hydrophobicizing, controlling chargeability, etc. It is also possible and preferable to treat with a treating agent such as a titanium compound or in combination with various treating agents.

In order to maintain a high charge amount, achieve a low consumption amount and a high transfer rate, it is more preferable that the inorganic fine powder is treated with at least silicone oil.

Further, in the present invention, transferability and / or
Alternatively, in order to improve the cleaning property, in addition to the inorganic fine powder, the primary particle diameter is more than 30 nm (preferably the specific surface area is less than 50 m ² / g), more preferably 5
0 nm or more (preferably specific surface area less than 30 m ² / g)
It is also one of the preferable modes to further add the inorganic or organic spherical particles. For example, spherical silica particles, spherical polymethylsilsesquioxane particles, spherical resin particles and the like are preferably used.

In the toner of the present invention, other additives, for example, Teflon powder, zinc stearate powder, polyvinylidene fluoride powder, lubricant powder; cerium oxide powder, silicon carbide Powder,
Abrasives such as strontium titanate powder; fluidity-imparting agents such as titanium oxide powder and aluminum oxide powder; anti-caking agent, or conductivity-imparting agents such as carbon black powder, zinc oxide powder and tin oxide powder; A small amount of organic fine particles and inorganic fine particles having opposite polarities can be used as a developing property improver.

A known method is used for producing the toner according to the present invention. For example, a binder resin, a wax,
Metal salts or metal complexes, pigments as colorants, dyes,
Alternatively, a magnetic material, if necessary, a charge control agent, other additives and the like 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. The metal compound, the pigment, the dye, and the magnetic substance are dispersed or dissolved in the resin to make them compatible with each other, and after solidification by cooling, pulverization and classification are performed to obtain the toner according to the present invention. In the classification step, it is preferable to use a multi-division classifier in terms of production efficiency.

Examples of the surface treatment include a hot water bath method in which pulverized toner particles are dispersed and heated in water, a heat treatment method in which a hot air stream is passed, and a mechanical impact method in which mechanical energy is applied for treatment. In the present invention, the processing temperature in the mechanical impact method is set to the glass transition point Tg of the toner particles.
The thermo-mechanical shock that adds a temperature near (Tg ± 10 ℃)
It is preferable from the viewpoint of aggregation prevention and productivity. More preferably, it is carried out at a temperature in the range of the glass transition point Tg ± 5 ° C. of the toner, in order to reduce the pores having a radius of 10 nm or more on the surface, to effectively work the inorganic fine powder, and to improve the transfer efficiency. It is valid.

The toner relating to the present invention is disclosed in Japanese Examined Patent Publication No. 56-56.
No. 13945, etc., a method of atomizing a molten mixture into air using a disk or a multi-fluid nozzle to obtain a spherical toner; JP-B-36-10231;
No. 53856, JP-A-59-61842, a method of directly producing a toner by using a suspension polymerization method, and an aqueous organic solvent in which a monomer is soluble but the obtained polymer is insoluble. It is possible to produce a toner by using a dispersion polymerization method in which a toner is directly produced using a polymer or an emulsion polymerization method typified by a soap-free polymerization method in which a toner is directly polymerized in the presence of a water-soluble polar polymerization initiator to produce a toner. .

The present invention is also effective when the surface of the image bearing member is mainly composed of a polymer binder. For example, when a protective film mainly composed of a resin is provided on an inorganic image bearing member such as selenium or amorphous silicon, or as a charge transporting layer of a function separation type organic image bearing member, a surface layer comprising a charge transporting material and a resin. In some cases, the above-mentioned protective layer may be further provided on it. As means for imparting releasability to such a surface layer, a resin having a low surface energy is used as the resin forming the film, water repellency,
Examples thereof include adding an additive that imparts lipophilicity, dispersing a material having a high mold release property into a powder, and dispersing the powder. For example, it is achieved by introducing a fluorine-containing group, a silicon-containing group or the like into the resin structure. For this, a surfactant or the like may be used as an additive. Examples thereof include compounds containing a fluorine atom, that is, powders of polytetrafluoroethylene, polyvinylidene fluoride, carbon fluoride and the like. Among these, polytetrafluoroethylene is particularly preferable. In the present invention, it is particularly preferable to disperse the releasable powder such as the fluorine-containing resin in the outermost surface layer.

By these means, the contact angle of water on the surface of the image bearing member can be 85 degrees or more (preferably 90 degrees or more). If it is less than 85 degrees, deterioration of the toner and the toner carrier due to durability tends to occur.

In order to contain these powders on the surface, a layer in which the powders are dispersed in a binder resin is provided on the outermost surface of the image bearing member, or an organic material mainly composed of a resin is used. In the case of an image carrier, the powder may be dispersed in the uppermost layer without providing a new surface layer.

The amount of the powder added to the surface layer is preferably 1 to 60% by mass, more preferably 2 to 50% by mass, based on the total mass of the surface layer. If it is less than 1% by mass, the effect of improving the durability of the toner and the toner carrier is insufficient, and 60% by mass
If it exceeds, the strength of the film is lowered, or the amount of light incident on the image carrier is significantly lowered, which is not preferable.

The present invention is particularly effective when the charging means is a direct charging method in which the charging member is brought into contact with the image carrier. Compared to corona discharge or the like in which the charging means does not come into contact with the image carrier, the load on the surface of the image carrier is large, so that the effect of improving the life of the image carrier is remarkable, which is one of the preferable application modes.

One of the preferable embodiments of the image bearing member used in the present invention will be described below.

As the conductive substrate, metals such as aluminum and stainless steel, aluminum alloys, indium oxide-
Cylindrical cylinders and films of plastic having a coating layer of tin oxide alloy, paper impregnated with conductive particles, plastic, plastic having conductive polymer, and the like are used.

On these conductive substrates, the adhesion of the photosensitive layer is improved, the coatability is improved, the substrate is protected, defects on the substrate are covered,
An undercoat layer may be provided for the purpose of improving the charge injection property from the substrate and protecting the photosensitive layer against electrical breakdown. The subbing layer is polyvinyl alcohol, poly-N-vinylimidazole, polyethylene oxide, ethyl cellulose, methyl cellulose, nitrocellulose, ethylene-acrylic acid copolymer, polyvinyl butyral, phenol resin, casein, polyamide, copolymerized nylon, glue,
It is formed of a material such as gelatin, polyurethane, aluminum oxide or the like. The film thickness is usually 0.1 to 10 μm,
It is preferably about 0.1 to 3 μm.

The charge generation layer includes azo pigments, phthalocyanine pigments, indigo pigments, perylene pigments, polycyclic quinone pigments, squarylium dyes, pyrylium salts, thiopyrylium salts, triphenylmethane dyes, selenium,
It is formed by dispersing a charge generating substance such as an inorganic substance such as amorphous silicon in a suitable binder and coating or vapor depositing. The binder can be selected from a wide range of binder resins, for example, polycarbonate resin, polyester resin, polyvinyl butyral resin, polystyrene resin, acrylic resin, methacrylic resin, phenol resin, silicone resin, epoxy resin, vinyl acetate resin, etc. Is mentioned. The amount of the binder contained in the charge generation layer is 80% by mass.
Below, it is preferably selected to be 0 to 40% by mass. The film thickness of the charge generation layer is preferably 5 μm or less, and particularly preferably 0.05 to 2 μm.

The charge transport layer has a function of receiving charge carriers from the charge generation layer in the presence of an electric field and transporting them. The charge transport layer is formed by dissolving a charge transport substance in a solvent, if necessary, together with a binder resin, and coating the solution, and the film thickness thereof is generally 5 to 40 μm. As the charge transport substance, biphenylene is added to the main chain or side chain,
Polycyclic aromatic compounds having a structure such as anthracene, pyrene and phenanthrene, nitrogen-containing cyclic compounds such as indole, carbazole, oxadiazole and pyrazoline,
Hydrazone compounds, styryl compounds, selenium, selenium-
Tellurium, amorphous silicon, cadmium sulfide, etc. may be mentioned.

As the binder resin in which these charge transporting substances are dispersed, polycarbonate resin, polyester resin, polymethacrylate ester, polystyrene resin,
Examples thereof include resins such as acrylic resins and polyamide resins, organic photoconductive polymers such as poly-N-vinylcarbazole, and polyvinylanthracene.

A protective layer may be provided as the surface layer. As the resin for the protective layer, polyester, polycarbonate, acrylic resin, epoxy resin, phenol resin, or a curing agent of these resins may be used alone or in combination.
Used in combination of more than one species.

Further, conductive fine particles may be dispersed in the resin of the protective layer. Examples of the conductive fine particles include metals and metal oxides, and preferably zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, bismuth oxide, tin oxide coated titanium oxide, tin coated indium oxide, Antimony coating There are ultrafine particles such as tin oxide and zirconium oxide. These may be used alone or in combination of two or more. Generally, when the particles are dispersed in the protective layer, it is necessary that the particle size of the particles is smaller than the wavelength of the incident light in order to prevent scattering of the incident light by the dispersed particles, and the particles are dispersed in the protective layer in the present invention. The particle diameter of the conductive and insulating particles is preferably 0.5 μm or less. The content in the protective layer is preferably 2 to 90% by mass, more preferably 5 to 80% by mass, based on the total mass of the protective layer. The thickness of the protective layer is preferably 0.1 to 10 μm, more preferably 1 to 7 μm.

The surface layer can be coated by spray coating, beam coating or permeation coating of the resin dispersion liquid.

The contact transfer step applicable to the image forming method of the present invention will be specifically described below.

In the contact transfer step, the developed image is electrostatically transferred to the transfer material while the electrostatic charge image carrier and the transfer material are in contact with each other via the transfer material. The contact pressure of the transfer means is linear pressure. It is preferably 2.9 N / m (3 g / cm) or more, more preferably 19.6 N / m (20 g / cm).
That is all. The linear pressure as the contact pressure is 2.9 N / m (3
If it is less than g / cm), transfer deviation of the transfer material and transfer failure are likely to occur, which is not preferable.

As the transfer means in the contact transfer step, an apparatus having a transfer roller or a transfer belt is used. The transfer roller is composed of at least a core metal and a conductive elastic layer, and the conductive elastic layer is made of urethane having a conductive material such as carbon dispersed therein or EPDM and has a volume resistance of 10 ⁶ to 1 1.
It is made of an elastic body of about 0 ¹⁰ Ωcm.

The present invention is particularly effectively used in an image forming apparatus in which the surface of the latent image carrier (photoreceptor) is an organic compound. That is, when the organic compound forms the surface layer of the photoconductor, the adhesiveness to the binder resin contained in the toner particles is better than that of other photoconductors using an inorganic material, and the transferability is further reduced. This is because there is a tendency to

Examples of the surface material of the photoreceptor according to the present invention include silicone resin, vinylidene chloride, ethylene-vinyl chloride, styrene-acrylonitrile, styrene-methyl methacrylate, styrene, polyethylene terephthalate and polycarbonate. Without being limited to these, other monomers or copolymers and blends between the above-mentioned binder resins can be used.

Further, the present invention is particularly effectively used for an image forming apparatus having a photoconductor having a small diameter of 50 mm or less. That is, in the case of a small-diameter photoconductor, the curvature with respect to the same linear pressure is large, and the pressure is likely to concentrate at the contact portion. Although it is considered that the same phenomenon occurs in the belt photoreceptor, the present invention has a radius of curvature of 25 at the transfer portion.
It is also effective for an image forming apparatus having a size of less than or equal to mm.

Further, the toner of the present invention is set so that the closest gap between the image carrier and the toner carrier is larger than the thickness of the toner layer on the toner carrier by means of the member for regulating the toner on the toner carrier. However, it is particularly preferable from the viewpoint of uniformly charging the toner that the member for regulating the toner on the toner carrier is regulated by the elastic member that is in contact with the toner carrier via the toner.

The surface roughness of the toner carrier used in the present invention is from 0.2 to JIS center line average roughness (Ra).
It is preferably in the range of 3.5 μm.

When Ra is less than 0.2 μm, the amount of charge on the toner carrier becomes high and the developability becomes insufficient. When Ra exceeds 3.5 μm, unevenness occurs in the toner coat layer on the toner carrier, resulting in uneven density on the image. More preferably, it is in the range of 0.5 to 3.0 μm.

Further, since the toner of the present invention has a high charging ability, it is desirable to control the total charge amount of the toner during development, and the surface of the toner carrier according to the present invention contains conductive fine particles and / or a lubricant. It is preferably covered with a dispersed resin layer.

As the conductive fine particles contained in the resin layer for coating the surface of the toner carrier, conductive metal oxides such as carbon black, graphite, conductive zinc oxide, and metal complex oxides may be used alone or in combination of two or more. It is preferably used. Further, as the resin in which the conductive fine particles are dispersed, a phenol resin, an epoxy resin, a polyamide resin, a polyester resin, a polycarbonate resin,
Known resins such as polyolefin resins, silicone resins, fluorine resins, styrene resins, and acrylic resins are used. A thermosetting or photocurable resin is particularly preferable.

When the one-component developing method is used in the present invention, the layer thickness smaller than the closest distance (between S and D) between the toner carrier and the latent image carrier is obtained on the toner carrier in order to obtain high image quality. Then, it is preferable that the development is performed in a developing process in which the magnetic toner is applied and an alternating electric field is applied to perform the development.

Further, in the present invention, it is preferable in terms of environmental protection that the charging member and the transfer member are in contact with the photosensitive member so that ozone is not generated.

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

Other charging means include a method using a charging blade and a method using a conductive brush. These contact charging means have an effect that a high voltage is unnecessary and ozone generation is reduced.

As the material of the charging roller and the charging blade as the contact charging means, 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), fluoroacrylic resin, etc. can be applied.

Next, the image forming method of the present invention will be specifically described with reference to the drawings.

In FIG. 1, a photosensitive drum 100 is provided with a primary charging roller 117, a developing device 140, a transfer charging roller 114, a cleaner 116, a resist roller 124 and the like around the photosensitive drum. And the photosensitive drum 100
Is charged to −700 V by the primary charging roller 117 (applied voltage is AC voltage −2.0 kVpp, DC voltage −700 Vdc). Then, the laser light 123 is applied to the photosensitive drum 100 by the laser generator 121, so that the photosensitive drum 100 is exposed. The electrostatic latent image on the photosensitive drum 100 is developed with a one-component magnetic toner by the developing device 140,
Transfer roller 1 that is in contact with the photosensitive drum via the transfer material
It is transferred onto the transfer material by 14. The transfer material on which the toner image is placed is conveyed to the fixing device 126 by the conveyor belt 125 or the like and fixed on the transfer material. The toner partially left on the electrostatic latent image carrier is cleaned by the cleaning unit 116.

As shown in FIG. 2, the developing device 140 is provided with a cylindrical toner carrier 102 (hereinafter referred to as a developing sleeve) made of a non-magnetic metal such as aluminum or stainless steel in the vicinity of the photosensitive drum 100. The gap between the photosensitive drum 100 and the developing sleeve 102 is maintained at about 300 μm by a sleeve / drum gap holding member (not shown). A stirring rod 141 is arranged in the developing device. A magnet roller 104 is fixed and arranged concentrically with the developing sleeve 102 in the developing sleeve. However, the developing sleeve 102 is rotatable. The magnet roller 104 is provided with a plurality of magnetic poles as shown in the drawing. S ₁ influences development, N ₁ regulates toner coat amount, S ₂ influences toner intake / conveyance, and N ₂ influences toner blowout prevention. There is. The elastic blade 1 is used as a member for controlling the amount of magnetic toner attached to the developing sleeve 102 and conveyed.
03 is arranged and the developing sleeve 10 of the elastic blade 103
The amount of toner conveyed to the developing area is controlled by the contact pressure with respect to 2. In the developing area, a DC and AC developing bias is applied between the photosensitive drum 100 and the developing sleeve 102, and the toner on the developing sleeve flies on the photosensitive drum 100 according to the electrostatic latent image and becomes a visible image.

[0105]

EXAMPLES The present invention will be specifically described below with reference to production examples and examples, but the present invention is not limited thereto. In the following formulation, all parts are parts by mass.

[0106]   (Toner Production Example 1)   ・ Magnetic material (average particle size 0.22 μm) 100 parts   ・ Styrene-butyl acrylate-butyl maleate half ester copolymer     (Low molecular weight peak: about 5000, glass transition point Tg: 58 ° C)                                                             100 copies   ・ Monoazo dye iron complex (negative charge control agent) 2 parts   ・ Low molecular weight polyolefin (release agent) 2 parts

The above materials were mixed in a blender,
Melted and kneaded with a twin-screw extruder heated to ℃, cooled and crushed the kneaded material roughly with a hammer mill, finely crushed the coarsely crushed material with a jet mill, and the resulting finely crushed material is multi-divided using the Coanda effect. Strict classification was carried out with a classifier to obtain magnetic toner particles. The magnetic toner particles were subjected to a surface treatment by a thermo-mechanical impact force (treatment temperature 60 ° C.), and the obtained magnetic toner particles were treated with 1.8% by mass of silicone oil and hexamethyldisilazane to make them hydrophobic. diameter 12nm dry silica (BET specific surface area after treatment 120 m ² / g) and 0.5 wt% of spherical silica (BET surface area 20 m ² /
g, primary particle size 0.1 μm) was added and mixed with a mixer to obtain a magnetic toner A.

The weight average particle diameter of the obtained magnetic toner is 6.
5 μm, number average particle size is 5.3 μm, SF-1 is 14
1, SF-2 is 125, BET specific surface area is 5.3 m ² /
It was cm ³ . The BET specific surface area of the toner particles was 1.7 m ² / cm ³ . Table 1 shows the physical properties of the obtained magnetic toner. In the present invention, the particle size was measured using a Coulter Counter Multisizer (manufactured by Coulter).

(Toner Production Example 2) The magnetic toner particles obtained in Toner Production Example 1 were hydrophobized with 1.3% by mass of hexamethyldisilazane to obtain a primary particle diameter of 12 nm.
Dry silica (BET specific surface area 160 m ² / g) was added and mixed with a mixer to obtain a magnetic toner B. Table 1 shows the physical properties of the obtained magnetic toner.

[0110]   (Toner Production Example 3)   ・ Magnetic material (average particle size 0.22 μm) 90 parts   ・ Styrene-butyl acrylate-butyl maleate half ester copolymer     (Low molecular weight side peak: about 10,000, glass transition point Tg: 62 ° C)                                                             100 copies   ・ Monoazo dye iron complex (negative charge control agent) 2 parts   ・ Low molecular weight polyolefin (release agent) 2 parts

Using the above materials, setting the treatment temperature of the toner particles by thermo-mechanical impact to 64 ° C., and using dry silica (BET specific surface area 100 m) having a primary particle size of 8 nm which has been hydrophobized with silicone oil as an inorganic fine powder. ² / g)
Was used in the same manner as in Toner Production Example 1 to obtain a magnetic toner C having a weight average particle size of 7.0 μm. Table 1 shows the physical properties of the obtained magnetic toner.

(Toner Production Example 4) As an inorganic fine powder
Dry silica having a primary particle size of 12 nm, which has been hydrophobized with 8% by mass of silicone oil and hexamethyldisilazane (B
A magnetic toner D was obtained in the same manner as in Toner Production Example 1 except that ET specific surface area 120 m ² / g) and 0.5% by mass of spherical silica (BET specific surface area 5 m ² / g, primary particle size 1 μm) were added. It was Table 1 shows the physical properties of the obtained magnetic toner.

(Toner Production Examples 5 and 6) Titanium oxide fine particles (BET specific surface area 100 m ² / g) having a primary particle size of about 20 nm, which were hydrophobized with silicone oil as inorganic fine powder,
Magnetic toners E and F were obtained in the same manner as in Toner Production Example 1 except that 1.5% by mass of alumina fine particles having a primary particle diameter of about 20 nm (BET specific surface area 90 m ² / g) were used.
Table 1 shows the physical properties of the obtained magnetic toner.

(Toner Production Example 7) A magnetic toner G was obtained in the same manner as in Toner Production Example 1 except that the surface treatment by thermo-mechanical impact was not performed. Table 1 shows the physical properties of the obtained magnetic toner.

[0115]   (Toner Production Example 8)   ・ Magnetic material (average particle size 0.24 μm) 110 parts   ・ Polyester resin     (Low molecular weight peak: about 7,000, glass transition point Tg: 63 ° C)                                                             100 copies   ・ Chromium complex of monoazo dye (negative charge control agent) 2 parts   ・ Low molecular weight polyolefin (release agent) 2 parts

A weight average particle diameter of 6.7 μm was obtained in the same manner as in Toner Production Example 1 except that the above materials were used and the treatment temperature of the toner particles by thermo-mechanical impact was 64 ° C.
Magnetic toner H of No. Table 1 shows the physical properties of the obtained magnetic toner.

[0117]   (Toner Production Example 9)   ・ Magnetic material (average particle size 0.22 μm) 60 parts   ・ Styrene-butyl acrylate copolymer     (Low molecular weight peak: about 18,000, glass transition point Tg: 71 ° C)                                                             100 copies   ・ Monoazo dye iron complex (negative charge control agent) 2 parts   ・ Low molecular weight polyolefin (release agent) 2 parts

The above materials were mixed in a blender, and 130
Melted and kneaded with a twin-screw extruder heated to ℃, cooled and crushed the kneaded material roughly with a hammer mill, finely crushed the coarsely crushed material with a jet mill, and the resulting finely crushed material is multi-divided using the Coanda effect. Strict classification was carried out with a classifier to obtain magnetic toner particles. 0.4% by mass based on the obtained magnetic toner particles
Dry silica having a primary particle size of about 16 nm that has been hydrophobized with hexamethyldisilazane (BET specific surface area after treatment 10
0 m ² / g) and mixed with a mixer to prepare magnetic toner I
Got The weight average particle diameter of the obtained magnetic toner I is 12 μm.
It was m. Table 1 shows the physical properties of the obtained magnetic toner.

(Toner Production Example 10) In the same manner as in Toner Production Example 1 except that the inorganic fine powder was not added to the toner particles,
A magnetic toner J was obtained. The physical properties of the obtained magnetic toner are shown in Table 1.
Shown in.

[0120]   (Toner Production Example 11)     100 parts of polyester resin     (Low molecular weight side peak: 6000, glass transition point Tg: 55 ° C)     Carbon black 7 parts     Metallic salicylate compound 2 parts

After sufficiently melting and kneading the above composition using an extruder, the cooled kneaded material is mechanically coarsely pulverized, and the coarsely pulverized material is collided with a collision plate using a jet flow to finely pulverize it, and further the Coanda effect is applied. The finely pulverized product was classified with a conventional airflow classifier, and the weight average diameter was 7.9 μm, and SF-1 was 17
0, SF-2 was 157, and black toner particles obtained by a pulverization method were obtained.
2% by mass of titanium oxide fine particles having a primary particle size of about 20 nm (BET specific surface area 100 m ² / g) hydrophobized with isobutyltrimethoxysilane were externally added to the obtained black toner particles to obtain a black toner K having excellent fluidity. It was

A two-component developer was prepared by mixing the above toner and a resin-coated ferrite carrier having an average particle size of about 50 μm at a ratio of 5:95. The physical properties of the obtained toner are shown in Table 1.
Shown in.

(Toner Production Example 12) The toner particles obtained in Toner Production Example 11 were subjected to thermomechanical impact force (processing temperature 60).
Surface treatment with isobutyltrimethoxysilane and silicone oil to make the primary particle size about 20
nm titanium oxide fine particles (BET specific surface area 100 m ² /
2% by mass of g) was externally added to obtain a black toner L.

(Toner Production Example 13) In Toner Production Example 1, the particles to be added to the toner particles are hydrophobized with 1.8% by mass of silicone oil and hexamethyldisilazane, and have a primary particle diameter of 12 nm. Primary particle size 4 treated with dry silica (BET specific surface area after treatment 120 m ² / g) and 0.5% by weight of hexamethyldisilazane
0 nm dry silica (BET specific surface area after treatment 40 m ²
/ G), a magnetic toner M was obtained in the same manner.

Physical properties of the toners A to M obtained are shown in Table 1. A two-component developer was prepared by mixing the toners K and L with a resin-coated ferrite carrier having an average particle size of about 50 μm at a ratio of 5:95. The obtained two-component developer was used in Example 8 and Comparative Example 4 described later.

[0126]

[Table 1]

(Photoreceptor Production Example 1) A photoreceptor having a diameter of 3
The base was a 0 mm Al cylinder. A layer having a structure as shown in FIG. 3 was sequentially laminated thereon by dip coating to prepare a photoconductor.

(1) Conductive coating layer: Mainly composed of tin oxide and titanium oxide powder dispersed in a phenol resin. Film thickness 15 μm.

(2) Undercoat layer: Mainly composed of modified nylon and copolymer nylon. The film thickness is 0.6 μm.

(3) Charge generating layer: Mainly composed of an azo pigment having absorption in a long wavelength region dispersed in butyral resin. The film thickness is 0.6 μm.

(4) Charge transport layer: Mainly composed of a hole-transporting triphenylamine compound dissolved in a polycarbonate resin (molecular weight of 20,000 by Oswald viscosity method) at a mass ratio of 8:10, and further polytetrafluoroethylene. 10% by mass of powder (particle size: 0.2 μm) was added to the total solid content and uniformly dispersed. The film thickness is 25 μm. The contact angle with water was 95 degrees.

The contact angle was measured using pure water, and the device used was a contact angle meter CA-DS type manufactured by Kyowa Interface Science Co., Ltd.

(Photoreceptor Production Example 2) A photoconductor was produced in the same manner as in Photoreceptor Production Example 1 without adding polytetrafluoroethylene powder. The contact angle with water was 74 degrees.

(Photoreceptor Production Example 3) A photoreceptor was prepared according to Photoreceptor Production Example 1 up to the charge generation layer. For the charge transport layer, a hole-transporting triphenylamine compound dissolved in a polycarbonate resin at a mass ratio of 10:10 was used. Film thickness 20 μm. Furthermore, as a protective layer, a polytetrafluoroethylene powder (particle size: 0.2 μm) was added to the composition obtained by dissolving the same material in a mass ratio of 5:10 in an amount of 30% with respect to the total solid content to obtain a uniform mixture. Was spray-coated on the charge transport layer. Film thickness 5 μm. The contact angle with water was 102 degrees.

Example 1 The image forming apparatus shown in FIGS. 1 and 2 was used.

As the electrostatic latent image carrier, the organic photoconductor (OPC) drum of Photoconductor Production Example 3 was used and the dark portion potential V _d = -70.
0V and bright part potential _VL = -210V. A gap between the photosensitive drum and the developing sleeve is 300 μm, a toner carrier having a layer thickness of about 7 μm and a JIS center line average roughness (Ra) of 0.8 μm is used as a toner carrier, and a surface is a mirror surface having a diameter of 16φ. Using a developing sleeve formed on an aluminum cylinder, a developing magnetic pole of 95 mT (950 gauss), a toner regulating member having a thickness of 1.0 mm and a urethane rubber blade having a free length of 10 mm, 14.7 N / m (15 g / cm).
It was made to contact by the linear pressure.

[0137]   Phenolic resin 100 parts   Graphite (particle size: about 7 μm) 90 parts   Carbon black 10 parts

Next, as a developing bias, a DC bias component V _dc = -500V and an AC bias component V to be superimposed
_PP = 1200V and f = 2000Hz were used. Also,
The peripheral speed of the developing sleeve is the peripheral speed of the photoconductor (48 mm / sec).
150% in the forward direction (reverse as the rotation direction)
Speed (72 mm / sec).

A transfer roller as shown in FIG. 7 (made of ethylene-propylene rubber in which conductive carbon is dispersed, volume resistance value of conductive elastic layer 10 ⁸ Ωcm, surface rubber hardness 24)
°, diameter 20 mm, contact pressure 49 N / m (50 g / cm)
Equal to the peripheral speed of the photoconductor (48 mm / sec),
+2000 V was applied as the transfer bias, the magnetic toner A was used as the toner, and the image was printed in the environment of 23 ° C. and 65% RH. As the transfer paper, 75 g / m ² paper was used.

At this time, the transfer efficiency from the photosensitive member to the transfer material was as high as 97%, which showed a high transfer efficiency of characters and lines, and a good image without scattering on the image was obtained.

In the present invention, the scattering evaluation is
It is a splattering evaluation in fine fine lines related to the image quality of a graphical image, and a splattering evaluation in a 100 μm wide line, which is more likely to scatter than characters and lines.

The transferability was evaluated by a value obtained by tapping off the transfer toner on the solid black photoconductor with a Mylar tape, peeling it off, and subtracting the Macbeth density of the one with only the tape from the Macbeth density of the one with the tape. did.

Further, when the image was continuously printed on up to 6000 sheets and the abrasion amount of the photoreceptor was measured by a film thickness meter, the abrasion amount was 0 to 1
It was very small at μm.

[0144] Using the toner B of Toner Production Example 2 As Example 2 Toner, except for using OPC drum photoreceptor Preparation Example 1 as an electrostatic latent image bearing member in the same apparatus and conditions as in Example 1 Ede I went to work.

At this time, the transfer efficiency from the photoconductor to the transfer material was as high as 95%, and there was no dropout of characters or lines in the transfer, and a good image without scattering on the image was obtained.

Comparative Example 1 Images were produced under the same apparatus and conditions as in Example 2 except that Toner G manufactured in Toner Production 7 was used as the toner. As a result, the transfer efficiency from the photoconductor to the transfer material was 89%, and the toner utilization efficiency was low. In addition, the image had a noticeable dropout of characters and lines.

Comparative Example 2 The same apparatus and conditions as in Example 1 were used except that Toner I of Toner Production Example 9 was used as the toner and the OPC drum of Photoconductor Production Example 2 was used as the electrostatic latent image carrier. I put it out. As a result, the transfer efficiency from the photoconductor to the transfer material is 85%.
Therefore, the transfer efficiency was lower than that in Example 1, and there were a large number of characters and lines in the transfer void, and the images were very scattered.

Comparative Example 3 The procedure of Comparative Example 2 was repeated except that the magnetic toner J was used instead of the magnetic toner A as the toner. As a result, the transfer efficiency was as low as less than 70%, the lines were thin, and there were many voids in the transfer of characters and lines, and the images were scattered and poor.

Examples 3 to 6 As the toner carrier, the layer thickness of the following constitution is about 7 μm, JIS
A developing sleeve was prepared by forming a resin layer having a center line average roughness (Ra) of 1.5 μm on a stainless steel cylinder having a diameter of 16φ, the surface of which was blasted.

[0150]   ・ Phenolic resin 100 parts   ・ Graphite (particle size: about 3 μm) 45 parts   ・ 5 parts of carbon black

The developing sleeve and the magnetic toners C, D, E and F of Toner Production Examples 3 to 6 are used as the toner, and the DC bias component Vdc = -500V, as the developing bias.
AC bias component to be superimposed Vpp = 1100V, f = 2
Image formation was performed under the same apparatus and conditions as in Example 1 except that the rotation speed was set to 000 Hz, and the peripheral speed Vt of the developing sleeve to the peripheral speed of the photosensitive member Vt / V was set to 2.0 to rotate in the forward direction. As a result, with the magnetic toners C and D, as in the case of Example 1, a good image having good transfer efficiency, no voids in the transfer of characters or lines, and no scattering on the image was obtained. Further, although the magnetic toners E and F had slightly low densities and the transfer efficiency was a little worse than that of the first embodiment, there was no problem in practical use and the transfer efficiency of the characters and lines was good, which is almost the same as the first embodiment. And a good image without scatter on the image was obtained.

Example 7 The magnetic toner H of Toner Production Example 8 was used as the toner,
DC bias component Vdc = -450 as developing bias
V, AC bias component to be superimposed Vpp = 1300V, f
Image is output under the same apparatus and conditions as in Example 1 except that the frequency is set to 2000 Hz, and the transfer efficiency is the same as in Example 1, there is no void in the transfer of characters or lines, and there is no scattering on the image. An image was obtained.

Example 8 Image formation was carried out under the same apparatus and conditions as in Example 2 except that the two-component magnetic brush development was carried out using Toner L of Toner Production Example 12 as the toner. As a result, as in the case of Example 2, a good image having good transfer efficiency, no voids in the transfer of characters or lines, and no scattering on the image was obtained.

Comparative Example 4 Image formation was performed using the same apparatus and conditions as in Example 8 except that Toner K of Toner Production Example 11 was used as the toner.
As a result, the transfer efficiency was lowered to 89%, and the image was slightly conspicuous in voids in characters and lines.

Example 9 Instead of the magnetic toner A as the toner, toner production example 13
A device similar to that of Example 1 except that the magnetic toner M is used.
Images were drawn under the conditions. At this time, the transfer efficiency from the photosensitive member to the transfer material was as high as 96%, and there was no omission of characters or lines during transfer, and a good image without scattering was obtained.

[0156]

According to the present invention, there is provided a toner having at least toner particles in which a colorant is dispersed in a binder resin and an inorganic fine powder, and having a shape factor SF-1 measured by an image analyzer of the toner. The value is 120 ≦ SF−1 ≦ 160,
The shape factor SF-2 has a value of 115 ≦ SF-2 ≦ 140, the ratio B / A has a value of 0.35 to 0.85, and the specific surface area per unit volume of the toner measured by the BET method. The relationship between Sb (m ² / cm ³ ) and the specific surface area St (m ² / cm ³ ) per unit volume calculated from the weight average particle diameter when the toner is assumed to be a true sphere has the following condition 3.0 ≦ Sb /St≦7.0 Sb ≧ St × 1.5 + 1.5, etc., and a developing step of forming a toner image using the toner on the electrostatic latent image carrier. By using an image forming method using an electrophotographic apparatus having a transfer step of transferring the toner image onto the transfer material while bringing a transfer member to which a voltage is applied into contact with the transfer material, high image density and latent image can be obtained. Improves voids in transfer and transfer efficiency while maintaining image reproducibility It becomes possible. Furthermore, a high-quality and sharp image can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of an image forming apparatus suitable for the present invention.

FIG. 2 is a schematic view showing an example of a developing unit for one-component development.

FIG. 3 is a schematic view showing an example of the configuration of a photoconductor used in the present invention.

FIG. 4 is a schematic view of a charge amount measuring device for measuring the charge amount of toner used in the present invention.

FIG. 5 is a diagram showing a good image (a) having no “transfer blank area” and a defective image (b) having “transfer blank area”.

FIG. 6 is a diagram showing a range of the present invention in shape factors SF-1 and SF-2.

FIG. 7 is a schematic view showing an example of a contact transfer member.

[Explanation of symbols]

100 photoconductor (electrostatic latent image carrier) 102 developing sleeve (toner carrier) 103 Contact blade 104 magnet roller 114 Transfer charging roller 116 cleaner 117 Primary charging roller 140 developer 141 stirring rod

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI G03G 15/08 507 G03G 15/08 507L (72) Inventor Yuki Nishio 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Satoshi Yoshida 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) Reference JP-A-1-185654 (JP, A) JP-A-6-317928 (JP, A) ) JP-A 61-273556 (JP, A) JP-A 4-204749 (JP, A) JP-A 1-113764 (JP, A) JP-A 5-346680 (JP, A) JP-A 6- 194862 (JP, A) JP-A 1-219758 (JP, A) JP-A 3-177847 (JP, A) JP-A 6-250413 (JP, A) JP-A 6-167817 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) G03G 9/08-9/087

Claims (32)

(57) [Claims] 1. A toner having at least toner particles in which a colorant is dispersed in a binder resin and an inorganic fine powder, wherein the shape factor SF-1 of the toner measured by an image analyzer is 120 ≦ SF−. 1 ≦ 160 and shape factor SF-2
Is 115 ≦ SF-2 ≦ 140, and the ratio B / A of the value B obtained by subtracting 100 from the value of SF-2 and the value A obtained by subtracting 100 from the value of SF-1 is 0.35. 0.85 or less, the specific surface area per unit volume as measured by the BET method of the toner ^{Sb (m 2 / cm 3)} , was calculated from the weight average particle diameter when assuming a toner and sphericity unit The relationship of the specific surface area St (m ² / cm ³ ) per volume satisfies the following conditions 3.0 ≦ Sb / St ≦ 7.0 Sb ≧ St × 1.5 + 1.5, and the specific surface area Sb is 3.2. ~ 6.8 (m ² / c
m ³ ) . Wherein said toner is 100 parts by mass of the binder resin The toner according to claim 1, wherein the magnetic material 30 to 200 parts by mass which is a magnetic toner containing chromatic. Wherein the inorganic fine powder titania contained in the toner, alumina, silica or claim 1 or 2, characterized in that one or more kinds of inorganic fine powder selected from among the mixed oxide The toner described. 4. The inorganic fine powder contained in the toner is hydrophobized.
4. The toner according to any one of 3 to 3 . 5. The toner according to claim 4 in which the hydrophobic inorganic fine powder contained in the toner is characterized in that treated with at least silicone oil. 6. The inorganic fine powder contained in the toner,
The primary particle size is 30 nm or less, and the toner is 30
The toner according to any one of claims 1 to 5 , further comprising a fine powder having a particle size of more than 10 nm. 7. The toner according to claim 6 , wherein the fine powder exceeding 30 nm is an inorganic fine powder. 8. The toner according to claim 6 , wherein the fine powder exceeding 30 nm is a resin fine powder. 9. A fine powder exceeding the 30nm, the toner according to any one of claims 6 to 8, wherein the substantially spherical. 10. The molecular weight distribution of the toner measured by GPC has a peak on the low molecular weight side of 3000 to 150.
The toner according to any one of claims 1 to 9, characterized in that in the range of 00. 11. The specific surface area per volume of the toner particles measured by the BET method is 1.2 to 2.5 m ² / c.
The toner according to any one of claims 1 to 10, characterized in that it is m ^3. 12. The method of claim 1 1 wherein the toner particles 60% pore radius in the cumulative pore area ratio curve of pores of 1nm~100nm of is equal to or less than 3.5nm
1. The toner according to any one of 1 . 13. The toner is a toner layer on a toner carrier.
Image formation with a step of controlling the thickness with an elastic blade
A toner used in a method.
13. The toner according to any one of 1 to 12. 14. The toner is a transfer roller or a transfer belt.
Forming method having contact transfer step by apparatus having
A toner used for a toner according to claim 1.
14. The toner according to any one of 13 to 13. 15. A developing step of developing an electrostatic latent image to form a toner image on an electrostatic latent image carrier, the toner image being brought into contact with a transfer member to which a voltage is applied to a transfer material. In an image forming method using an electrophotographic apparatus having a contact transfer step of transferring onto a transfer material, the toner is toner having at least toner particles in which a colorant is dispersed in a binder resin and inorganic fine powder, The value of the shape factor SF-1 measured by the toner image analyzer is 1
20 is ≦ SF-1 ≦ 160, the value of shape factor SF-2 is the 115 ≦ SF-2 ≦ 140, minus 100 from the value of the value B and SF-1 minus 100 from the value of SF-2 The value of the ratio B / A to the value A is 0.35 to 0.85 or less, and the specific surface area Sb (m ² / cm ³ ) per unit volume of the toner measured by the BET method is The relationship of the specific surface area St (m ² / cm ³ ) per unit volume calculated from the weight average particle diameter when assuming a true sphere has the following condition 3.0 ≦ Sb / St ≦ 7.0 Sb ≧ St × 1. 5 + 1.5, and the specific surface area Sb is 3.2 to 6.8 (m ² / c
m ³ ) is an image forming method. To 16. The toner binder resin 100 parts by weight, the image forming method according to claim 15, characterized in that the magnetic 30 to 200 parts by mass which is a magnetic toner containing chromatic. 17. The method of claim 15 or 1 6, characterized in that the inorganic fine powder contained in the toner is titania, alumina, silica or one or more inorganic fine powder selected from the mixed oxide the image forming method according to. 18. The inorganic fine powder contained in the toner is hydrophobized.
The image forming method according to any one of 15 to 17. 19. The image forming method according to claim 18, wherein the hydrophobized inorganic fine powder contained in the toner is at least treated with silicone oil. 20. The inorganic fine powder contained in the toner has a primary particle diameter of 30 nm or less, and the toner is
20. The image forming method according to claim 15 , further comprising a fine powder having a particle size exceeding 30 nm. 21. The image forming method according to claim 20, wherein the fine powder exceeding 30 nm is an inorganic fine powder. 22. The image forming method according to claim 20, wherein the fine powder exceeding 30 nm is a resin fine powder. 23. The image forming method according to claim 20, wherein the fine powder having a particle size of more than 30 nm is substantially spherical. 24. The peak on the low molecular weight side is 3000 to 150 in the molecular weight distribution measured by GPC of the toner.
Claims 15 to 23, characterized in that in the range of 00
The image forming method according to any one of 1. 25. The specific surface area per volume of the toner particles measured by the BET method is 1.2 to 2.5 m ² / c.
The image forming method according to claim 15, wherein the image forming method is m ³ . 26. The toner according to claim 15 , wherein a 60% pore radius in an integrated pore area ratio curve of pores of 1 nm to 100 nm of the toner particles is 3.5 nm or less. Image forming method. 27. The contact angle of the surface of the electrostatic latent image carrier is 8.
27. The image forming method according to claim 15, wherein the image forming angle is 5 degrees or more. 28. The image forming method according to claim 27, wherein the surface of the electrostatic latent image bearing member contains a substance containing fluorine. 29. The image forming method according to claim 28, wherein the substance containing fluorine on the surface of the electrostatic latent image carrier is fine powder containing fluorine. 30. The transfer member is a transfer roller or a transfer bell.
30. Any of claims 15 to 29, characterized in that
An image forming method according to claim 1. 31. The electrophotographic apparatus is provided on a toner carrier.
To have an elastic blade for controlling the toner layer thickness
The image according to any one of claims 15 to 30, characterized in that
Imaging method. 32. An alternating electric field is applied to the toner carrier.
32. The developing process according to claim 31, wherein the developing process is performed from
Image forming method.