JP2000352845A - Image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming method by which image density is not changed and line reproducibility is not lowered even in the case of performing continuous printing for many sheets. SOLUTION: This image forming method includes an electrifying stage for electrifying a latent image carrier 1 by bringing a contact electrifying means into contact with the carrier 1, a latent image forming stage for forming an electrostatic latent image on the electrified carrier 1, and a developing stage for forming a toner image by carrying two-component type developer having toner 19a and magnetic carrier 19b and developing the electrostatic latent image with the toner of the two-component type developer. In the method, the volume resistance value (A) of the surface layer of the latent image carrier is 108 to 1014 Ω.cm, the toner incorporates binding resin and carbon black, the weight average particle of the toner is 3 to 10 μm, and the average primary particle diameter of the carbon black is 13 to 60 mμ. Assuming that the number of particles of a flocculated lump having <10 primary particles in a dispersed state in the toner is (a) and the number of particles of the flocculated lump having >=10 primary particles is (b), a<=b is satisfied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method for forming and developing an electric latent image in an electrophotographic method, an electrostatic printing method, and the like. The present invention relates to an image forming method for developing the latent image, which is stable for a long period of time and has stable injection chargeability and developability.

[0002]

2. Description of the Related Art Conventionally, many methods have been known as electrophotography. In general, a photoconductive substance is used to form an electrostatic latent image on a photoreceptor by charging means and image exposure means. Then, the latent image is developed with toner to form a visible image (toner image), and after transferring the toner image to a transfer material such as paper, the toner image is fixed on the transfer material by heat and / or pressure. A copy is to be obtained. At this time, the toner remaining on the photoconductor without being transferred onto the transfer material is removed from the photoconductor by a cleaning process.

In recent years, various organic photoconductive materials have been developed as photoconductive materials for electrophotographic photoreceptors, and in particular, a function-separated type having a charge generation layer and a charge transport layer laminated thereon has been put into practical use.
It is installed in copiers, printers, and facsimile machines. As a charging unit in such an electrophotographic apparatus, a unit using corona discharge has been used. However, since a large amount of ozone is generated, it is necessary to provide a filter. There was a problem of up.

As a technique for solving such a problem, a charging member such as a roller or a blade is brought into contact with the surface of a photoreceptor to form a narrow space in the vicinity of the contacting portion, which is interpreted according to the so-called Paschen's law. A charging method has been developed in which the generation of ozone is suppressed as much as possible by forming a discharge as possible. Among them, a roller charging method using a charging roller as a charging member is particularly preferably used from the viewpoint of charging stability.

Since the charging is performed by discharging from the charging member to the member to be charged, the charging is started by applying a voltage higher than a certain threshold voltage. For example, when a charging roller is brought into contact with a photosensitive member containing an organic photoconductive substance having a photosensitive layer thickness of about 25 μm, the surface potential of the photosensitive member increases when a voltage of about 640 V or more is applied. After that, the photoconductor surface potential linearly increases with a slope of 1 with respect to the applied voltage. Thereafter, this threshold voltage is set to the charging start voltage Vth
Is defined. That is, in order to obtain the photoconductor surface potential Vd, the charging roller needs a DC voltage higher than Vd + Vth. Furthermore, since the resistance value of the charging roller fluctuates due to environmental fluctuations or the like, it has been difficult to set the potential of the photoconductor to a desired value.

Therefore, as disclosed in Japanese Unexamined Patent Publication No. 63-149669, in order to achieve different charging uniformity, an AC voltage having a peak-to-peak voltage of 2 × Vth or more is applied to a DC voltage corresponding to a desired Vd. A DC + AC charging system in which a voltage on which a voltage is superimposed is applied to a contact charging roller is used. This is for the purpose of the potential leveling effect of the AC, and the potential of the member to be charged converges to Vd, which is the center of the peak of the AC voltage, and is hardly affected by disturbance such as environmental fluctuation.

However, even in such a charging method, the essential charging mechanism uses a discharging phenomenon from the charging member to the photosensitive member, so that the voltage required for charging is as described above. A value higher than the photoconductor surface potential is required. Further, generation of vibration and noise (hereinafter referred to as AC charging noise) of the charging member and the photoconductor due to the electric field of the AC voltage,
And the deterioration of the photoreceptor surface due to discharge becomes remarkable,
It was a new problem.

[0008] As disclosed in JP-A-61-57958, there is an image forming method in which a photosensitive member having a conductive protective film is charged using conductive fine particles. In this publication, a photoconductor having a semiconductive protective film having a resistance of 10 ⁷ to 10 ¹³ Ω · cm is used as a photoconductor, and this photoconductor is made of conductive fine particles having a resistance of 10 ¹⁰ Ω · cm or less. It is described that, by charging using this method, the photoreceptor can be uniformly charged without unevenness without injecting electric charge into the photosensitive layer, and good image reproduction can be performed. According to this method, vibration which is a problem in AC charging,
Noise can be prevented, but the charging efficiency is not sufficient.In addition, the toner adheres to the charging member due to scraping of the transfer residual toner by the conductive fine particles serving as the charging member. Change takes place.

As a charging method having higher charging efficiency, a so-called injection charging in which charges are directly injected into a photosensitive member is known.

[0010] A method of performing charging by applying a voltage to a contact charging member such as a charging roller, a charging fiber brush, or a charging magnetic brush to inject a charge into a trap level on the surface of a photoreceptor is disclosed in Japan Hardcopy, 1992. P
287, “Contact Charging Characteristics Using Conductive Rollers” and the like. In these methods, injection charging is performed on a photosensitive member that is insulated in a dark place with a low-resistance charging member to which a voltage is applied. This is a method in which the resistance value of the charging member is sufficiently low, and a material (such as a conductive filler) that makes the charging member conductive.
Had to be sufficiently exposed on the surface.
For this reason, the above-mentioned literature also states that the charging member is preferably an aluminum foil or an ion-conductive charging member having a sufficiently reduced resistance value in a high-humidity environment. According to the study of the present inventors, the resistance value of the charging member capable of sufficiently injecting electric charge into the photoreceptor is 1 × 10 ³ Ω · cm or less. It has been found that a problem arises in the convergence of the charging potential which starts to occur.

However, when such a charging member having a low resistance value is actually used, an excessive leakage current flows from the charging member into a flaw or a pinhole generated on the surface of the photoreceptor, and poor charging around the pinhole or pinhole. And the energization breakdown of the charging member is likely to occur.

In order to prevent this, the resistance of the charging member must be about 1 × 10 ⁴ Ω · cm or more. There is a contradiction that the injectability decreases and charging is not performed sufficiently.

In view of the above, the above-mentioned problems with the contact-type charging device or the image forming method using the charging device are solved, that is, the photosensitive member which cannot be prevented by the low-resistance charging member. It has been desired to achieve both contradictory characteristics of pinhole leak.

As described above, in the image forming method using the charging member brought into contact with the photoreceptor, an image defect tends to occur due to poor charging due to contamination (spent) of the charging member, and a problem tends to occur in durability. Also, in charging by charge injection into the photoreceptor, it is urgently necessary to prevent the influence of charging failure due to contamination of the charging member in order to enable printing of many sheets.

The inventors of the present invention have conducted intensive studies on the surface layer of a latent image carrier such as a photosensitive member used for charging by charge injection and the contact charging member. As a result, the resistance (B) of the contact charging member was reduced. 10 ⁴ ~10 ⁹ Ω · cm, when the resistance of the surface layer of the latent image bearing member (a) to 10 ⁸ ~10 ¹⁵ Ω · cm, since a sufficient charging property can be obtained, it was found that preferred.

However, if a conductive material such as carbon black, which is used as a colorant for a so-called black toner, is unevenly distributed or released on the toner surface, the latent image charge on the photoconductor is reduced. It has been found that a satisfactory image cannot be obtained due to disturbance or a transfer electric field leaking to the photoreceptor via the toner surface during transfer. Such poor transfer is remarkable especially in a cleanerless system having no cleaning means for removing transfer residual toner between the transfer portion and the charging portion.

[0017]

SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming method which solves the above-mentioned problems.

That is, an object of the present invention is to provide an image forming method that does not cause a change in image density and a decrease in line reproducibility even when a large number of continuous prints are performed.

An object of the present invention is to have sharp image characteristics,
Another object of the present invention is to provide an image forming method free from halftone roughness.

An object of the present invention is to provide an image forming method which is stable in image density regardless of the environment and has excellent durability stability without fog.

An object of the present invention is to have sharp image characteristics,
Another object of the present invention is to provide an image forming method having excellent durability stability.

[0022]

According to the present invention, there is provided a charging step of charging a latent image carrier by bringing a contact charging means into contact with a latent image carrier for carrying an electrostatic latent image; A latent image forming step of forming an electrostatic latent image on an image carrier, a developing container holding a two-component developer having a toner having toner particles and a magnetic carrier, and the two-component developing held in the developing container Using a developing device having a developer carrier for carrying the developer and transporting the developer to the developing area, the electrostatic latent image carried on the latent image carrier in the developing area is converted to a two-component developer. In an image forming method including a developing step of forming a toner image by developing with a toner, the surface layer of the latent image carrier has a volume resistance value (A) of 10 ⁸ to 10 ¹⁴ Ω · cm, At least a binder resin and carbon black, The amount average particle diameter is 3 to 10 μm, the average primary particle diameter of the carbon black is 13 to 60 mμ, and in the dispersed state in the toner, the number of primary particles is less than 10; The present invention relates to an image forming method, wherein a ≦ b, where b is the number of particles of 10 or more aggregates.

The present invention also provides a charging step of charging a latent image carrier by bringing a contact charging means into contact with a latent image carrier for carrying an electrostatic latent image. A latent image forming step of forming an electrostatic latent image, a developing container holding a one-component developer having toner particles, and carrying the one-component developer held in the developing container, and transporting the developer to a developing area A developing device having a developer carrier for carrying the electrostatic latent image carried on the latent image carrier in a developing area at least on the developer carrier on the surface of the latent image carrier. In the image forming method having a developing step of forming a developer image by bringing a developer layer of a one-component developer into contact with the developer layer, the surface layer of the latent image carrier has a volume resistance (A) of 10%.
⁸ to 10 ¹⁴ Ω · cm, the toner contains at least a binder resin and carbon black, the weight average particle size of the toner is 3 to 10 μm, and the average primary particle size of the carbon black is 13 to 10 μm. 60 μm, and in the dispersed state in the toner, a ≦ b where a is the number of agglomerates having less than 10 primary particles and b is the number of agglomerates having 10 or more primary particles. Image forming method.

As a result of diligent studies, the present inventor can control the dispersion state of carbon black by combining carbon black with specific properties and a specific azo-based metal compound. Release can be suppressed, and as in the present invention, 10 ⁸ to 10 ¹⁴
Even when a latent image carrier having a surface layer controlled to a relatively low resistance value of Ωcm is used, there is no leakage of latent image charges through the toner surface, and the electric field when a transfer electric field is received. No leakage occurred, and an image having excellent fine line reproducibility and excellent solid image density stability was achieved.

JP-A-7-064337 also discloses DBP
Although there is a description of a combination of carbon black having a small oil absorption and an iron compound having a specific structure, the effect of stabilizing the charge of the toner is recognized, but the surface layer controlled to a relatively low resistance value as in the present invention is used. When combined with a latent image carrier having the same, it was not always satisfactory.
This tendency becomes more remarkable than when the toner is a polymerization toner.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Conventionally, carbon black is a material which is difficult to disperse as compared with other pigments. In particular, when applied to polymerization toners, sufficient shearing force is not exerted in the polymerizable monomer. Was very difficult to obtain a uniform dispersion. The present inventor has solved this problem by combining a specific azo metal compound and carbon black having a small oil absorption, preferably in the presence of a solid wax.

Carbon black having a small oil absorption, such as carbon black used in the present invention, is difficult to disperse, and it is difficult to achieve both improvement in coloring power and charging characteristics of the toner.

However, the present inventors have found that when a specific azo-based metal compound is used as a dispersant, the dispersibility in particles is far greater than that of conventionally used carbon black, especially in the presence of solid wax. It has been found that the toner has improved properties and is less likely to be present on the toner surface, and conversely has better charging characteristics than the conventional toner containing carbon black.

In producing the suspension polymerization toner, at least the above specific carbon black and the above specific azo-based iron compound are contained in the polymerizable monomer used in order to sufficiently disperse the pigment. By performing a pre-dispersion master batch process, the carbon black can be dispersed at a higher concentration with respect to the polymerizable monomer, so that a shearing force is more easily applied to the dispersion, and the dispersion effect of the carbon black is improved. It is particularly preferable because it becomes large. At this time, if the oil absorption of the carbon black is 30 to 100 ml / 100 g, this effect is more remarkable.

If the oil absorption exceeds 100 ml / 100 g, carbon black tends to be present on the toner surface, and it is particularly difficult to improve the transferability of the toner under high humidity and the coloring power of the toner. On the other hand, the oil absorption is 30ml / 100g
If it is less than 1, the dispersibility of the carbon black in the toner particles is not sufficient, and the coloring power and the charge amount of the toner tend to decrease.

The carbon black has an oil absorption of preferably 30 to 70 ml / 100 g, more preferably 35 to 70 ml / 100 g.
It is good to be ~ 55ml / 100g.

The carbon black used in the present invention is:
The average primary particle diameter is 13 to 60 mμ, preferably 25 to 5
The thickness is preferably 5 mμ, more preferably 25 to 45 mμ.

The average primary particle diameter of carbon black is 13
When the particle size is smaller than mμ, even if a specific azo metal compound used in the present invention and a solid wax are combined, uniform dispersion is difficult, it is difficult to master the use, and the toner surface is very fine. Easily released from On the other hand, when the average primary particle size is larger than 60 mμ, the coloring power of the toner is too low even if dispersed well,
If used in a large amount in order to increase the coloring power, the charge of the toner is reduced, which is not suitable for use.

In the present invention, in the state where carbon black is dispersed in the toner, the number of agglomerates having less than 10 primary particles is a, and the number of agglomerates of 10 or more is b. Another feature is that a ≦ b ≦ 3a. When a> b, the conductivity of the toner is increased, the charging under high humidity becomes unstable, and fog, toner scattering, and the like are easily caused.

According to the study by the present inventors, the content A [wt] of the carbon black is based on the weight of the toner particles.
%] And the content B [wt] of the azo metal complex compound.
%] Preferably satisfies the following relationship 3 ≦ A / B ≦ 40, and more preferably satisfies the following relationship 3 ≦ A / B ≦ 30.

If the amount of the azo-based metal compound is too small relative to the carbon black, the dispersion state is unstable even in the presence of solid wax, and the coloring power tends to decrease. Further, carbon black is easily released on the toner surface.

If the amount of the azo-based metal compound is too large relative to the carbon black, the azo-based metal compound is liable to cause secondary agglomeration and dispersibility, and the secondary agglomerate is liable to inhibit polymerization. It is difficult to take out.

In the present invention, the content A [% by weight] of the carbon black with respect to the weight of the toner particles is preferably 2 to 20% by weight, more preferably 3 to 15% by weight, and still more preferably 5 to 13% by weight. This is advantageous in terms of high image density, toner charging stability, and uniform dispersion of carbon black.

When the content A of the carbon black is less than 2% by weight, the coloring power as a toner is low, and a high image density cannot be achieved. Even if a solid wax having a structure is used, encapsulation of carbon black is not achieved, and as a result, suppression of fog, toner scattering, and the like deteriorate.

In the present invention, the content B [% by weight] of the azo metal compound with respect to the weight of the toner particles is preferably 0.1 to 3.0% by weight, more preferably 0.3 to 2.0% by weight.
0% by weight, more preferably 0.5 to 1.5% by weight is preferable in that the viscosity of the dispersion is maintained in an appropriate state and the uniform dispersibility of carbon black is improved.

If the content B of the azo metal compound is less than 0.1% by weight, the viscosity of the dispersion does not increase, and the effect of improving the dispersibility of carbon black is not exhibited.
If it exceeds, the viscosity of the dispersion liquid will decrease,
After all, the effect of improving the dispersibility of carbon black disappears.

As described above, the present inventor has made it possible to use a carbon black having a low oil absorption, which has not been usually used, in combination with a specific azo metal compound in the presence of a solid wax having a long-chain branched structure. Thus, the present invention succeeded in obtaining electrophotographic characteristics superior to those of the suspension polymerization toner using carbon black.

The azo metal compound used in the present invention has a structure represented by the following formula (1).

[0044]

Embedded image [M represents a metal element. R ₁ and R ₃ are a hydrogen atom, C ₁
To ₁₈ alkyl groups, C ₂ to ₁₈ alkenyl groups, sulfonamide groups, mesyl groups, sulfonic acid groups, carboxyester groups, hydroxy groups, C ₁ to ₁₈ alkoxy groups, acetylamino groups, benzoylamino groups or halogen atoms Wherein R ₁ and R ₃ are the same or different, and n and n ′
Represents an integer of 1 to 3, R ₂ and R ₄ represent a hydrogen atom or a nitro group, R ₂ and R ₄ are the same or different,
R ₅ and R ₆ are a hydrogen atom, a halogen atom, a nitro group, a carboxyl group, an anilide group, an alkyl group of C ₁ ~ _18, an alkenyl group, an aralkyl group, an alkoxy group, an aryl group, carboxy ester group, or

[0045]

Embedded image X represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a nitro group or a halogen atom, m represents an integer of 1 to 3, R ₅ and R ₆ are the same or different,
A ⁺ represents a hydrogen ion, a sodium ion, a potassium ion, an ammonium ion or a mixture thereof. ]

Among the compounds represented by the above general formula (1), particularly, an iron compound represented by the following general formula (2) is dispersible in the polymerizable monomer of the present invention and is present on the toner surface in an aqueous medium. This is preferable in that the toner particle size distribution becomes sharp.

[0047]

Embedded image [M represents a metal element. X ₁ and X _{2 each} represent a hydrogen atom, a lower alkyl group, a lower alkoxy group, a nitro group or a halogen atom; X ₁ and X ₂ are the same or different;
And m 'is an integer of 1 to 3, R ₁ and R ₃ is a hydrogen atom, an alkyl group of C ₁ ~ _18, an alkenyl group of C ₂ ~ _18, a sulfonamide group, a mesyl group, a sulfonic acid group, carboxy ester group, hydroxy group, an alkoxy group of C ₁ ~ _18,
An acetylamino group, a benzoylamino group or a halogen atom; R ₁ and R ₃ are the same or different; n and n ′ each represent an integer of 1 to 3; R ₂ and R ₄ represent a hydrogen atom or a nitro group; A ⁺ represents a hydrogen ion, a sodium ion, a potassium ion, an ammonium ion or a mixture thereof. ]

The azo metal compound is also used as a negative charge control agent in the toner. This azo-based iron compound can be synthesized by known means.

According to the study of the present inventors, the mechanism by which the azo metal compound represented by the above general formula (1) improves the dispersibility of a specific carbon black in a polymerizable monomer is as follows. I believe.

That is, the azo metal compound of the present invention comprises:
It has a moderate wettability to the polymerizable monomer, and there is no problem such as foaming, so that the dispersion viscosity of carbon black can be controlled stably, so the manufacturing latitude for dispersing carbon black is A wide and uniform dispersion state is achieved in a short time.

Representative specific examples of the azo metal complex compound represented by the general formula (2) include the following compounds.

[0052]

Embedded image

[0053]

Embedded image

[0054]

Embedded image

[0055]

Embedded image

In the present invention, the content of the solid wax with respect to the weight of the toner particles is preferably 0.1 to 5.0.
% By weight, more preferably 0.3 to 3.0% by weight, and still more preferably 0.3 to 2.0% by weight can stabilize the dispersion state of carbon black and thoroughly incorporate the carbon black.

If the content is less than 0.1% by weight, the encapsulation of carbon black is insufficient, so that poor charging is apt to occur, and fog and toner scattering are liable to occur. On the other hand, when the content exceeds 5% by weight, the fluidity of the toner deteriorates, and as a result, fog and toner scattering easily occur due to durability.

If necessary, additives may be added to the toner used in the present invention as long as the properties of the toner are not impaired. Examples of such additives include Teflon, zinc stearate, and polyvinylidene fluoride. And transfer aids such as silica particles, silicone resin particles, alumina particles, organic resin particles, and fixing aids (eg, low molecular weight polyethylene, low molecular weight polypropylene, etc.).

In the production of the toner particles used in the present invention, a method in which the constituent materials are thoroughly kneaded by a hot kneader such as a hot roll, kneader or extruder, and then obtained by mechanical pulverization and classification; A method in which a toner material such as a colorant is dispersed and then spray-dried; and a method in which a predetermined material is mixed with a polymerizable monomer capable of constituting a binder resin, and then this suspension is polymerized. A method for producing a polymerized toner for obtaining toner particles.

Among them, it is possible to produce toner particles having a particle size close to a particle size capable of achieving a high transfer efficiency required when a cleaner system is used, and it is difficult to generate free surplus which does not contain a colorant. From the viewpoint, it is preferable that the toner particles are produced by a polymerization toner production method.

In the present invention, the weight average particle diameter (D ₄ ) of the toner particles is preferably 3 to 10 μm, and more preferably _{4 to 9} μm, in order to achieve both high image density and high image quality.

When the weight average particle diameter of the toner particles is less than 3 μm, defects such as toner scattering and fog occur, and
If m exceeds m, the reproducibility of fine dots is reduced, or scattering occurs during transfer, which hinders high image quality.

Further, in the present invention, the toner particles are preferably produced by a polymerization method.
Since carbon black is unlikely to cause polymerization inhibition as described above, the resulting toner particles also have a small content ratio of ultrafine powder or agglomerated coarse particles of toner particles, and have a sharp particle size distribution. .

As for the particle size distribution of the toner particles, 20% by number or less, preferably 5 to 15%
Number%, 1.5% by volume of toner particles of 12.7 μm or more
Hereinafter, preferably 0.1 to 1.3% by volume,
This is preferable because the charge of the toner is made uniform.

If toner particles having a particle size of 4 μm or less are more than 20% by number, fogging is likely to occur due to toner reuse, particularly when applied to a cleaner-less system as an example of the present invention.

On the other hand, if the amount of toner particles having a particle size of 12.7 μm or more is more than 1.5% by volume, scattering is likely to occur particularly when applied to an intermediate transfer member system which is an example of the present invention.

Further, in the present invention, the dispersion state of carbon black in the toner particles is such that when the cross section of the toner is observed with a transmission microscope, the carbon black is more present in the binder resin toward the center of the toner. It is desirable that the toner does not exist much on the toner surface layer.

In the present invention, non-magnetic toner and non-magnetic toner particles refer to toner and toner particles having a saturation magnetization of 20 Am ² / kg or less.

In the present invention, the non-magnetic toner preferably has a volume resistivity of 10 ¹⁰ to 10 ¹⁶ Ωcm, more preferably 10 ¹² to 10 ¹⁶ Ωcm, and still more preferably 10 ¹³ Ωcm.
Over a long period it is to 10 ¹⁶ [Omega] cm, or in that to stabilize the charging of toner.

The volume resistivity of the non-magnetic toner is 10 ¹⁰ Ωcm
If it is less than 10%, the charge of the toner is apt to decrease particularly under high humidity. If it exceeds 10 ¹⁶ Ωcm, the image density is particularly low when the original document having an image area ratio of 2% or less is continuously printed under low humidity. Tends to decrease, which is not preferable.

In the present invention, when the toner is formed, the carbon black and the azo-based metal compound are pre-dispersed in the polymerizable monomer to be used in the dispersion in the masterbatch step. The effect of improving the performance is remarkable. This is because carbon black is dispersed at a higher concentration with respect to the polymerizable monomer, so that the viscosity can be increased and the dispersion effect is large. Furthermore, even if the second wax is diluted with the second polymerizable monomer in the presence of the solid wax, the carbon black hardly re-aggregates.

The polymerizable monomers used in the toner of the present invention include styrene monomers such as styrene, o (m-, p-)-methylstyrene and m (p-)-ethylstyrene; ) Methyl acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, (meth) (Meth) acrylate monomers such as behenyl acrylate, 2-ethylhexyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, and diethylaminoethyl (meth) acrylate; butadiene; isoprene; cyclohexene; ) Acrylonitrile; acrylamide is preferred. These may be used alone or as a mixture. When used in a mixture, the publication Polymer Handbook 2nd edition III-P139-19
2 (manufactured by John Wiley & Sons), and the monomers are used in an appropriate combination so that the theoretical glass temperature (Tg) indicates 40 to 75 ° C. If the theoretical glass transition temperature is less than 40 ° C., it is not preferable from the viewpoint of the storage stability of the toner and the durability stability of the developer. If the glass transition temperature exceeds 75 ° C., the fixing point is increased. However, the color mixing of each color toner is insufficient and the color reproducibility is poor, and the transparency of the OHP image is remarkably reduced, which is not preferable from the viewpoint of high image quality.

In the present invention, the GP of the resin component of the toner
In the molecular weight distribution by C (gel permeation chromatography), the weight average molecular weight (Mw) is preferably 5,000 to 1,000,000, and more preferably 7,000 to 500,000. The ratio (Mw) between the average molecular weight (Mw) and the number average molecular weight (Mn)
/ Mn) is preferably 2 to 100, more preferably 3
A value of from 50 to 50 is suitable for preventing the contamination of the toner charging member with a wide fixing latitude.

The weight average molecular weight (M
When w) is less than 5,000, the non-offset region on the high-temperature side becomes narrower, and at the same time, the toner charging member is easily contaminated, and the toner is poorly charged. 1,
When the amount exceeds 1,000,000, the fixing property is deteriorated.

Further, when Mw / Mn of the resin component of the toner is less than 2, the fixable temperature range becomes extremely narrow, and when it exceeds 100, the black image sinks when applied to a full-color image. The feeling is uncomfortable, which is not preferable.

The azo metal compound used in the present invention includes:
Although it also has a function as a charge control agent, another charge control agent may be used in combination. Known charge control agents that can be used in combination can be used. Specific examples of the negative compound include salicylic acid, naphthoic acid, a metal compound of dicarboxylic acid, a sulfonic acid, a polymer compound having a carboxylic acid in a side chain, a boron compound, a urea compound,
Examples of the positive compound include a quaternary ammonium salt, a polymer compound having the quaternary ammonium salt in a side chain, a guanidine compound, and an imidazole compound.

In the present invention, for the purpose of improving the releasability of the fixing member at the time of heat fixing, a solid wax component, which is a hydrocarbon compound, may be further used in the toner particles, also having the function of the releasing agent. preferable. Examples of the wax component preferably used as a mold release agent in the present invention include ester waxes and modified products thereof (for example, oxides and grafted products), higher fatty acids and metal salts thereof, and amide waxes. These waxes are used in the ring and ball method (JIS
Those having a softening point according to K 2531) of 40 to 130 ° C, preferably 50 to 120 ° C, are good. When the softening point of the wax component is less than 40 ° C., the blocking resistance and shape retention of the toner are insufficient, and when it exceeds 130 ° C., the effect of the releasability is insufficient.

In the present invention, an ester wax having a long-chain alkyl group can be preferably used, and specifically, an ester wax satisfying the following general formula is preferred.

[0079]

Embedded image [In the above formula, R ₁ and R ₂ each represent a hydrocarbon group having 15 to 45 carbon atoms.]

Further, in the present invention, an ester wax containing the ester compound represented by the above formula and containing 50 to 95% by weight of the ester compound having the same total number of carbon atoms is used. It is particularly preferred to use a wax composition.

In the present invention, the content of the ester compounds having the same total carbon number was measured by a gas chromatography method (GC method) described below.

In the present invention, the gas chromatogram was measured using GC-17A (manufactured by Shimadzu Corporation). At this time, a solution previously dissolved at a concentration of 1% by weight in toluene is used as a measurement sample, and 1 microliter of the solution is injected into a GC device equipped with an on-column injector. The column is
Ultra Alloy-1 with 0.5mm diameter x 10m length
(HT) was used. The column has an initial temperature of 40 ° C,
From there, 40 ° C / min. At a heating rate of 200 ° C. and further at 15 ° C./min. At 350 ° C., and then at 7 ° C./min. 450 ° C at heating speed
Temperature. The carrier gas is He gas at 50 kP.
It flowed on the pressure condition of a. When identifying the compound species, an alkane with a known carbon number is separately injected, measured at the same effluent time as above, and the obtained gas chromatograms are compared with each other. The structure was identified by methods such as incorporation into chromatography. The content of the ester compound having the same carbon number was calculated by calculating the ratio of each peak area to the total peak area of the chromatogram.

In the present invention, an ester wax particularly preferably used as an ester wax having a long-chain alkyl group is generally synthesized from a higher carboxylic acid component, similarly to a higher alcohol component. These higher alcohol and higher carboxylic acid components are usually obtained from natural products in many cases, and are generally composed of a mixture having an even number of carbon atoms. When these mixtures are esterified as they are, by-products having various similar structures are produced as by-products in addition to the intended ester compound, so that each property of the toner is likely to be adversely affected. For this reason, in the present invention, it is preferable to use an ester wax obtained by purifying raw materials or products using a solvent extraction or vacuum distillation operation.

In the measurement by the gas chromatography method described above, when the content of the ester compound having the same total number of carbon atoms is less than 50% by weight, complicated crystal polymorphism and freezing point drop occur, so that the toner When it is contained in the toner, it tends to be one of the causes mainly having an adverse effect on the anti-blocking property and the developing property of the toner. Further, in the present invention, when the ester compound as described above is used, it is difficult to obtain a predetermined fluidity of the toner, and filming due to the ester wax is easily generated on the carrier particles and the photoreceptor surface. In addition, the frictional charge amount of the toner decreases, and it is difficult to continuously obtain a sufficient frictional charge amount.

Therefore, in the present invention, ester compounds having the same total number of carbon atoms in the ester wax are preferably 55 to 95% by weight, more preferably 6 to 95% by weight.
It is good to use what is contained in the range of 0 to 95% by weight. Further, in the present invention, the ester compound having the same total number of carbon atoms contained most in the ester wax, and the total number of carbon atoms is ±
The total content of the ester compound including the ester compound in the range of 2 is preferably 80 to 95% by weight, more preferably 90 to 95% by weight.

The most preferred ester wax for constituting the toner according to the present invention is preferably an ester wax represented by the following general formula, in which the ester compound having a carbon number of 44 is 50 to 95% by weight in the ester wax. The degree is included.

[0087]

Embedded image [Wherein R ₁ ′ and R ₂ ′ represent a linear long-chain alkyl group having 15 to 45 carbon atoms]

Further, the ester compound represented by the above formula may be a compound wherein R ₁ ′ and R ₂ ′ are a saturated hydrocarbon group, more preferably an alkyl group, further preferably a linear alkyl group. preferable. In particular, when R ₁ ′ has 1 carbon atom
An ester compound having a linear alkyl group of 5 to 45 and R ₂ 'being a linear alkyl group of 16 to 44 carbon atoms is preferable. Specific examples of such compounds include the following ester compounds.

[0089]

Embedded image

As the ester wax having the above ester compound used in the toner of the present invention, when the endothermic curve is measured according to ASTM D3418-8, the main maximum peak (main peak) value of the endothermic curve is measured. (Hereinafter referred to as “melting point”) is 40 to 90
C, more preferably in the range of 55-85 C,
It is preferable for improving the low-temperature fixability and the offset resistance of the toner.

That is, an ester wax having a melting point of less than 40 ° C. has a low self-cohesive force,
As a result, there is a tendency that the high-temperature offset resistance of the toner is reduced. On the other hand, an ester wax having a melting point higher than 90 ° C. performs good granulation and polymerization in an aqueous medium when toner particles are obtained by a direct polymerization method. This tends to make it difficult to form granules having a sharp particle size distribution.

In the present invention, ASTM D3418-
The measurement according to 8 was performed using Perkin-Elmer DSC-7. The temperature of the detector was corrected using the melting points of indium and zinc, and the calorific value was corrected using the heat of fusion of indium. For the sample, an aluminum pan was used, an empty pan was set as a control, and the temperature was raised at a rate of 10 ° C./mi.
n. Was measured.

The ester wax used in the present invention preferably has a hardness of 0.5 to 5.0. The hardness of this ester wax is 20 mm in diameter.
After preparing a cylindrical sample having a thickness of 5 mm by using a dynamic ultra-micro hardness tester (DUH-20) manufactured by Shimadzu Corporation
0) is a value obtained by measuring Vickers hardness. As the measurement conditions, the load speed was 9.67 m with a load of 0.5 g.
After displacing 10 μm under m / sec and holding for 15 seconds, the resulting dent shape was measured to determine the Vickers hardness. According to the study of the present inventors, when an ester wax having a hardness measured by the above method of less than 0.5 is used, the pressure dependency and the process speed dependency of the fixing device become large, and the hot offset resistance is increased. The sexual effect tends to decrease. On the other hand, when the hardness exceeds 5.0, the storage stability of the toner decreases, and the self-cohesive force of the ester wax itself is small, so that the high-temperature offset resistance tends to decrease.

The ester wax used in the present invention preferably has a weight average molecular weight (Mw) of 200 to 2,000 and a number average molecular weight (Mn) of 150 to 2,000, more preferably 300 to 2,000. Those having 1,000 and Mn of 250 to 1,000 are preferred. That is, Mw
Is less than 200 and Mn is less than 150, the blocking resistance of the toner is reduced, and a low molecular weight component is easily present on the surface, and the fluidity of the toner is reduced. On the other hand, when Mw is 2,000
When an ester wax exceeding 0 and Mn exceeding 2,000 is used, granulation properties are inhibited in the production of toner, and coalescence of the toner is likely to occur.

In the present invention, the molecular weight distribution of the wax was measured by GPC under the following conditions.

(GPC measurement conditions) Apparatus: GPC-150C (manufactured by Waters) Column: GMH-HT 30 cm double (manufactured by Tosoh Corporation) Temperature: 135 ° C. Solvent: o-dichlorobenzene (added with 0.1% ionol) Flow rate: 1 0.0 ml / min sample: Inject 0.4 ml of 0.15% sample

Measurement was performed under the above conditions, and the molecular weight of the sample was calculated using a molecular weight calibration curve prepared from a monodisperse polystyrene standard sample. Furthermore, Mark-Hou
It was calculated by converting into polyethylene using a conversion formula derived from the win viscosity formula.

In the present invention, the black toner may contain another resin in addition to the resin synthesized by the polymerization of the polymerizable monomer.

The black toner particles further containing such other resin may be added to at least a polymerizable monomer, carbon black and an azo metal compound in addition to the other resin in the process of producing black toner particles by a polymerization method. To prepare a polymerizable monomer composition, and polymerize the polymerizable monomer composition thus prepared.

For example, hydrophilic groups such as amino group, carboxylic acid group, hydroxyl group, sulfonic acid group, glycidyl group and nitrile group which cannot be used because they dissolve in an aqueous suspension to cause emulsion polymerization due to water solubility. When a polymerizable monomer component containing a functional group is introduced into toner particles, a copolymer such as a random copolymer, a block copolymer, or a graft copolymer of these and a vinyl compound such as styrene or ethylene is used. Or in the form of a polycondensation product such as polyester or polyamide, or a polyaddition product such as polyether or polyimine. The coexistence of such a high molecular polymer containing a polar functional group in the toner particles makes it possible to phase-separate the above-mentioned wax component during polymerization of the polymerizable monomer composition in an aqueous medium, thereby making the toner particles more encapsulated. This is a preferred embodiment, since it makes the toner more powerful and can improve the performance of the toner targeted by the present invention.

The content of the high molecular polymer containing a polar functional group with respect to the weight of the toner particles is preferably 1 to
The content is preferably 20% by weight, more preferably 2 to 16% by weight.

When the content of the high molecular polymer containing a polar functional group is less than 1% by weight, the amount of the encapsulated wax is too small to appear on the toner surface and exert the releasing effect.
If the content exceeds 0% by weight, it becomes difficult to incorporate the wax, and as a result, the contamination of the toner charging member is accelerated, which is not preferable.

The weight average molecular weight of the high molecular polymer containing a polar functional group is preferably 5,000 or more.
When the weight average molecular weight is less than 5,000, particularly less than 4,000, the high molecular polymer containing a polar functional group tends to be concentrated near the surface, so that adverse effects on developability and blocking resistance are likely to occur, which is not preferable. .

When a polymer having a molecular weight different from the molecular weight range of the toner obtained by polymerizing the polymerizable monomer is dissolved in the polymerizable monomer composition and polymerized, a polymer having a wide molecular weight distribution can be obtained. A toner having high offset resistance can be obtained.

In the present invention, examples of the polymerization initiator used for producing toner particles by the polymerization method include 2,2′-azobis- (2,4-dimethylvaleronitrile) and 2,2′-azobis Isobutyronitrile,
1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis-4-methoxy-2,4-
Azo or diazo polymerization initiators such as dimethyl valeronitrile and azobisisobutyronitrile; peroxides such as benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide and lauroyl peroxide A system polymerization initiator is used.

The amount of the polymerization initiator to be added varies depending on the desired degree of polymerization, but it is generally 0.5 to 20% by weight based on the polymerizable monomer, which controls the molecular weight distribution of the toner. In addition, it is preferable to increase the latitude of the reaction conditions. The type of the polymerization initiator varies slightly depending on the polymerization method, but may be used alone or in combination with reference to the 10-hour half-life temperature.

When the toner particles are produced by a polymerization method, it is also possible to produce a toner particle by further adding a known crosslinking agent, chain transfer agent and polymerization inhibitor in order to control the degree of polymerization.

In the present invention, as a dispersant used in the polymerization step, for example, inorganic oxides such as tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, hydroxyapatite, calcium carbonate, magnesium carbonate, and calcium hydroxide , Magnesium hydroxide,
Examples include aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, alumina, magnetic material, and ferrite. Examples of the organic compound include polyvinyl alcohol, gelatin, methylcellulose, methylhydroxypropylcellulose,
Ethyl cellulose, sodium salt of carboxymethyl cellulose, starch and the like are used by being dispersed in an aqueous phase.
It is preferable to use 0.2 to 10 parts by weight of these dispersants with respect to 100 parts by weight of the polymerizable monomer since a sharp particle size distribution is achieved and toner particles are united.

As these dispersants, commercially available ones may be used as they are, but in order to obtain finely dispersed particles having a uniform particle size, the inorganic compound may be produced under high-speed stirring in a dispersion medium. it can. For example, in the case of tricalcium phosphate, a dispersant suitable for a suspension polymerization method can be obtained by mixing an aqueous solution of sodium phosphate and an aqueous solution of calcium chloride under high-speed stirring. A surfactant may be used in an amount of 0.001 to 0.1 part by weight to make these dispersants finer. Specifically, commercially available nonionic, anionic, and cationic surfactants can be used, and examples thereof include sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, potassium stearate, and olein. Calcium acid is preferably used.

The black toner particles according to the present invention can be specifically manufactured by the following manufacturing method.

[0111] Carbon black and an azo metal compound, and if necessary, a charge control agent, a polymerization initiator, and other additives are added to the polymerizable monomer, and the mixture is uniformly mixed with a mixing device such as a homogenizer or a media disperser. The polymerizable monomer composition is prepared by dissolving or dispersing. The polymerizable monomer composition thus prepared is dispersed in an aqueous phase containing a dispersion stabilizer using a conventional mixer or a mixing device such as a homomixer or a homogenizer. Preferably, the stirring speed and time are adjusted such that the droplets of the polymerizable monomer composition have the desired size of the toner particles, and the granulation is performed.
Thereafter, by the action of the dispersion stabilizer, the particles may be stirred to such an extent that the particle state is maintained and the particles are prevented from settling. The polymerization is performed at a polymerization temperature of 40 ° C. or higher, generally 50 to 90 ° C. The temperature may be raised in the latter half of the polymerization reaction. Further, in order to improve durability in the image forming method using the toner of the present invention, the polymerization reaction is performed to remove unreacted polymerizable monomers and by-products. The aqueous medium may be partially distilled off in the second half or after the end of the polymerization reaction. After completion of the polymerization reaction, the generated toner particles are washed, collected by filtration,
dry. In the suspension polymerization method, the monomer system 100
It is preferable to use 300 to 3000 parts by weight of water as a dispersion medium with respect to parts by weight.

In the method for producing black toner particles of the present invention, as described above, in order to improve the dispersibility of carbon black in the toner particles, a polymerizable monomer composition is prepared through a master batch process. .

Specifically, based on 100 parts by weight of the first polymerizable monomer, preferably 10 to 40 parts by weight, more preferably 10 to 25 parts by weight of carbon black and preferably 0.2 to 5 parts by weight. By mixing and dispersing the azo metal compound in an amount of 0.5 parts by weight, more preferably 0.5 to 3 parts by weight, carbon black can be mixed at a very high concentration with respect to the polymerizable monomer. Of the azo-based metal compound can significantly improve the dispersibility of carbon black.

When the mixing amount of carbon black is less than 10 parts by weight, even when an azo-based metal compound is used, the viscosity of the dispersion is small, and it is difficult to achieve sufficient dispersion. On the other hand, if it exceeds 40 parts by weight, it becomes difficult to control the viscosity of the dispersion, and as a result, the dispersion tends to be uneven.

When the amount of the azo metal compound is less than 0.2 parts by weight, the effect of increasing the viscosity of the dispersion is insufficient, while when the amount exceeds 5 parts by weight, the viscosity increases. And dispersion tends to be non-uniform.

The viscosity of the (masterbatch) dispersion containing the first polymerizable monomer, carbon black and an azo metal compound, and if necessary, a wax component and / or a charge control agent is preferably 100 to 100. It is good to be 2000 centipoise, more preferably 150-1600 centipoise.

When the viscosity of the dispersion is less than 100 centipoise, the viscosity is too low and the share of dispersion is not applied.
Uniform dispersion of carbon black becomes difficult. On the other hand, 20
When the viscosity exceeds 00 centipoise, the viscosity is too high, and it is difficult to maintain a uniform dispersion state, and at the same time, the dischargeability is deteriorated and the productivity is reduced.

This dispersion is mixed with the second polymerizable monomer and the first wax component of the present invention, a high molecular polymer having a polar functional group, a charge control agent, a polymerization initiator and a second solid wax. And a polymerizable monomer composition by mixing with other additives.

The mixing amount of the second polymerizable monomer with respect to 100 parts by weight of the dispersion is preferably 20 to 100 parts by weight, more preferably 30 to 70 parts by weight. Is good in terms of uniform dispersibility in a polymerizable monomer.

When the mixing amount of the second polymerizable monomer is less than 20 parts by weight, it takes time to disperse uniformly, and when it exceeds 100 parts by weight, re-agglomeration of carbon black is required. Etc. are likely to occur, and it also takes time for uniform dispersion.

The content ratio of carbon black in the polymerizable monomer composition relative to the weight of the polymerizable monomer composition is preferably 2 to 20% by weight, more preferably 3 to 1%.
An amount of 5% by weight is good in terms of the coloring power of the toner and the stabilization of the charging of the toner.

When the content of carbon black in the polymerizable monomer composition is less than 2% by weight, it is difficult to achieve a high image density. The charge of the toner under high humidity tends to be low.

The content ratio of the azo metal compound in the polymerizable monomer composition relative to the weight of the polymerizable monomer composition is preferably 0.1 to 3.0% by weight, more preferably 0.1 to 3.0% by weight. The content of 2 to 2.0% by weight is preferable in that the viscosity of the dispersion is maintained in an appropriate state and the uniform dispersibility of carbon black is improved.

When the content of the azo metal compound in the polymerizable monomer composition is less than 0.1% by weight, the effect of improving the dispersibility of carbon black is exhibited without increasing the viscosity of the dispersion. On the other hand, when the content exceeds 3.0% by weight, the viscosity of the dispersion liquid is reduced, and the effect of improving the dispersibility of carbon black is also lost.

Next, various measuring methods according to the present invention will be described.

(1) Measurement of DBP Oil Absorption of Carbon Black Measured according to JIS 4656/1.

(2) Measurement of Specific Surface Area of Carbon Black by Nitrogen Adsorption It is measured according to JIS 4652.

(3) Measurement of Volatile Content of Carbon Black Measured according to JIS 1126.

(4) Method of Measuring Average Primary Particle Diameter of Carbon Black and Aggregated Particle Diameter in Toner A cross section of the toner was taken with a transmission microscope at a magnification of 50,000 times, and 100 primary particles and Aggregated particles 3
Zero is randomly selected, the average primary particle size is calculated, and the aggregated particle size is measured.

(5) Toner weight average particle diameter (D ₄ ) and the number% of toner particles having a particle size of 4.0 μm or less and 10.1 μm
Measurement of Volume% of Toner Particles Above average particle size and particle size distribution of toner are measured using Coulter Counter T
It can be measured using A-II or Coulter Multisizer II (manufactured by Coulter), but in the present invention, Coulter Multisizer II (manufactured by Coulter) is used.
And an interface (manufactured by Nikkaki) for outputting a number distribution and a volume distribution and a PC9801 personal computer (manufactured by NEC) are connected, and a 1% aqueous NaCl solution is prepared using primary-grade sodium chloride as an electrolytic solution. For example, I
SOTON R-II (manufactured by Coulter Scientific Japan) can be used. As a measurement method, 0.1 to 5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant to 100 to 150 ml of the electrolytic aqueous solution, and 2 to 20 mg of a measurement sample is further added. The electrolyte in which the sample was suspended was mixed with an ultrasonic
After a dispersion treatment for a minute, the volume and the number of toner particles having a size of 2 μm or more were measured using the Coulter Multisizer with an aperture of 100 μm as an aperture to calculate a volume distribution and a number distribution. Then, the weight average particle diameter (D ₄ ) obtained from the volume distribution according to the present invention (the representative value of each channel is taken as the representative value of each channel) and the toner particles having a particle size of 4.0 μm or less obtained from the number distribution. Number%
And the volume% of toner particles of 10.1 μm or more determined from the volume distribution.

(6) GPC Molecular Weight Distribution of Resin Component of Toner Particles and High Molecular Polymer Containing Polar Functional Group As a specific method for measuring GPC of resin component of toner particles and high molecular polymer containing polar functional group, Is to extract the toner particles in advance with a toluene solvent using a Soxhlet extractor for 20 hours, then distill off the toluene with a rotary evaporator, and if necessary, dissolve the wax added to the toner particles but dissolve the resin component. After adding an organic solvent that cannot be used, for example, chloroform, and washing well,
A solution obtained by dissolving a solution dissolved in HF (tetrahydrofuran) was filtered through a solvent-resistant membrane filter having a pore diameter of 0.3 μm, and a sample was formed using 150C manufactured by Waters Corporation.
805, 806 and 807 are connected, and the molecular weight distribution is measured using a standard polystyrene resin calibration curve.

From the obtained molecular weight distribution, a weight average molecular weight (Mw) and a number average molecular weight (Mn) are calculated.

The charging member used in the present invention may be in any form such as a conductive magnetic brush using conductive magnetic particles, a conductive fiber brush using conductive fibers, and a conductive roller. . However, a conductive magnetic brush or a conductive fiber brush is preferable for application to a cleaner-less system, and a conductive magnetic brush is more preferable for stabilizing charging including durability regardless of the environment. preferable.

The conductive magnetic brush charger preferably used in the present invention has a nonmagnetic sleeve, a magnet contained in the sleeve, and conductive magnetic particles magnetically constrained on the sleeve by the magnetic force of the magnet. It is.

The weight average particle diameter of the magnetic particles for charging is 5 to 5.
The thickness is preferably 45 μm, more preferably 10 to 45 μm, and still more preferably 20 to 40 μm.

When the weight average particle diameter of the magnetic particles for charging is smaller than 5 μm, the charging property is good, but the magnetic binding force is reduced, and as a result, the charging magnetic particles detached from the conductive magnetic brush charger are latent. Since the development process is performed in a state where it is also adhered to the surface of the image carrier, the charging magnetic particles may be mixed into the developing container, which may disturb the electrostatic latent image during development. Weight average particle diameter of magnetic particles for charging is 45μ
If it is larger than m, the brush ears of the charging magnetic particles are in a coarse state, and charging unevenness is likely to occur, and image quality is likely to deteriorate.

The charging member used in the present invention has a volume resistance of 10 ⁷ to 10 ¹¹ Ω · cm, preferably 10 ⁷ to 10 ^9.
It is better to be less than Ω · cm.

When the volume resistance of the charging member is less than 10 ⁷ Ω · cm, it is difficult to prevent the magnetic particles as the charging member from adhering to the latent image carrier. When the volume resistance value of the charging member exceeds 10 ¹¹ Ω · cm, the ability to impart charge to the latent image carrier is reduced particularly under low humidity, and poor charging is likely to occur.

Further, it is more preferable that the magnetic particles for charging have a surface layer on the surface of the core material. Examples of such a surface layer include a coupling agent such as a silane coupling agent and a titanium coupling agent, a conductive resin or a resin containing conductive fine particles (preferably a fluororesin or a silicone resin).

The coupling agent particularly preferably used in the present invention has a structure in which 6 or more carbon atoms are linearly connected to a hydrophobic group portion. As an effect obtained by including this configuration, in terms of triboelectric charging, the electron donating property of the alkyl group makes it possible to easily impart a negative polarity particularly in triboelectric charging. Further, the alkyl group is relatively resistant to oxidation and resistant to mechanical or thermal deterioration due to friction between the charging magnetic particles. Furthermore, even if the molecular chain is cut by the above-mentioned mechanical or thermal load when it is a long chain, the remaining portion is an alkyl group, so that from the viewpoint of triboelectric charging, there is little change over a long period of time. This is probably the reason.

From this viewpoint, the alkyl group needs to be continuous with 6 or more carbon atoms, preferably 8 or more carbon atoms, and it is considered that the number of carbon atoms can be reduced to 30 or less. When the carbon number of the alkyl group is 3
If it exceeds 0, it tends to be insoluble in the solvent, making it difficult to uniformly treat the surface of the magnetic particles for charging. Further, the fluidity of the treated magnetic particles for charging deteriorates, and the charging property becomes poor. It tends to be uniform.

The processing amount of the coupling agent is preferably 0.0001 to 0.5% by weight, more preferably 0.001 to 0.2% by weight, based on the magnetic particles for charging.

When the treatment amount of the coupling agent is less than 0.0001% by weight, the effect of the coupling agent is hardly exhibited. If the treatment amount of the coupling agent exceeds 0.5% by weight, the flowability of the magnetic particles for charging tends to deteriorate.

In the present invention, it is basically desirable that the surface of the magnetic particles for charging is composed of only a coupling agent, but it is also possible to coat a small amount of a resin component. In this case, an amount equivalent to the amount of the coupling agent is preferable.

As the coupling agent used in the present invention, the central element is not particularly limited as long as the hydrophobic group has a structure in which six or more carbon atoms are linearly connected. Examples of the central element include titanium, aluminum, silicon and zirconium.

The coupling agent in the present invention refers to a compound having a hydrolyzable hydrolyzable group and a hydrophobic group in the same molecule and bonded to a central element such as silicon, aluminum, titanium and zirconium.

Examples of the hydrolyzable group include a methoxy group, an ethoxy group, a propoxy group,
An alkoxy group such as a butoxy group, an acryloxy group, a methacryloxy group, a halogen, and a modified form thereof are also used.

As the hydrophobic group, any structure may be used as long as it has a structure in which 6 or more carbon atoms are linearly connected in its structure.
In the form of the bond with the central element, the bond may be a carboxylate, an alkoxy, a sulfonate, a phosphate or a direct bond. Further, the structure may contain a functional group such as an ether bond, an epoxy group, or an amino group.

Further, when an iron powder carrier or a ferrite carrier such as copper-zinc-ferrite and nickel-zinc-ferrite which is conventionally preferably used as a developing carrier constituting the two-component developer of the present invention is used, As described above, the electrostatic latent image formed on the latent image carrier is disturbed.

The developing carrier used in the present invention has a volume resistivity of 10 ⁹ to 10 ¹⁵ Ω · cm, preferably 10 ^13.
It is preferable that the value be super to 10 ¹⁵ Ω · cm.

The volume resistance of the developing carrier is 10 ⁹ Ω ·
If it is less than cm, since the resistance is low, a developing bias is injected in the developing area, and the latent image is disturbed. When the volume resistivity of the developing carrier exceeds 10 ¹⁵ Ω · cm, the carrier itself is charged up, and the charge-imparting ability of the replenishment toner is likely to be reduced.

Therefore, as a carrier for development used in the present invention, a resin-coated carrier in which the surface of a carrier core is coated with a resin is preferable. As the carrier core, a magnetite-containing polymerized resin carrier core produced by a polymerization method is preferable.

As the polymerized resin carrier core, Fe ₃
In addition to O ₄ , metal oxides such as Fe ₂ O ₃ , Al ₂ O ₃ ,
It preferably contains SiO ₂ , CaO, SrO, MgO, MnO or a mixture thereof. The amount of Fe ₃ O ₄ is preferably 0.2 to 0.8 (weight ratio) based on all oxides.

The polymerized resin carrier core can be easily formed into a spherical shape and a sharp particle size distribution can be achieved due to its production method. It is advantageous for adhesion to the body. Therefore, the 50% particle size of the polymerized resin carrier core is 10 to 45 μm, preferably 15 to 40 μm.
It is good to have μm.

The metal oxide contained in the polymerized resin carrier core used in the present invention is preferably subjected to lipophilic treatment in order to prevent the metal oxide fine particles from being detached. When the lipophilic metal oxide is dispersed in a binder resin to form core particles, the metal oxide can be uniformly and densely incorporated into the binder resin.
In particular, when the carrier core particles are formed by a polymerization method, it is important to obtain spherical particles having a smooth surface.

In the lipophilic treatment, it is preferable to surface-treat a coupling agent such as a silane coupling agent, a titanate coupling agent, or an aluminum coupling agent, or various surfactants.

In particular, it is preferable to perform a surface treatment with at least one selected from the group consisting of a silane coupling agent, a titanate coupling agent, and a surfactant.

As the silane coupling agent, those having a hydrophobic group, an amino group or an epoxy group can be used. Examples of the silane coupling agent having a hydrophobic group include vinyltrichlorosilane, vinyltriethoxysilane, and vinyltris (β-methoxy) silane. Examples of the silane coupling agent having an amino group include γ-aminopropyltrimethoxysilane, γ-aminopropylmethoxydiethoxysilane,
γ-aminopropyltriethoxysilane, N-β (aminoethyl) -γ-aminopropyltrimethoxysilane,
N-β (aminoethyl) -γ-aminopropylmethyldimethoxysilane and N-phenyl-γ-aminopropyltrimethoxysilane. Examples of the silane coupling agent having an epoxy group include γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane, and β- (3,4-epoxycyclohexyl) trimethoxysilane.

Examples of titanate coupling agents include isopropyl triisostearoyl titanate,
Examples thereof include isopropyl tridodecylbenzenesulfonyl titanate and isopropertor (dioctyl pyrophosphate) titanate.

As the surfactant, a commercially available surfactant can be used.

In the carrier used in the present invention, as a coating resin for coating the surface of the carrier core, a specific crosslinkable silicone resin or a copolymer of a fluororesin and an acrylic resin can be preferably used, and particularly preferably,
A crosslinkable silicone resin having a hydrolysis reaction group and whose curing is accelerated by the hydrolysis reaction is preferred.

Further, the carrier for development used in the present invention preferably has a 50% particle size (median diameter) of from 20 to 50%.
The thickness of 50 μm, more preferably 20 to 45 μm, is good in terms of uniformity of a solid image and reproducibility of minute dots. In the present invention, the 50% particle size refers to a particle size of a volume-based central cumulative value (50%).

If the 50% particle size of the developing carrier is larger than 50 μm, the uniformity of the solid image and the reproducibility of fine dots tend to decrease. 50% of carrier for development
If the particle size is less than 20 μm, the carrier for development tends to adhere to the photoreceptor, causing damage to the photoreceptor and causing image deterioration.

In the present invention, the apparent density of the carrier for development is preferably 1.2 to 3.2 g / c.
m ² , more preferably 1.5 to 2.8 g / cm ² .

If the apparent density of the developing carrier is smaller than the lower limit of the above range, carrier adhesion is likely to occur.
When the apparent density of the developing carrier is larger than the upper limit of the above range, the circulation of the two-component developer is deteriorated, and not only the toner is easily scattered but also the image quality is deteriorated.

Further, the carrier for development used in the present invention preferably has a saturation magnetization of 20 to 65 Am ² / kg, and preferably 20 to 45 Am ² / kg in order to favorably carry and carry the toner and carrier on the developing sleeve. Having magnetic properties is more preferable in terms of uniformity of a solid image and reproducibility of fine lines, since the density of the developing carrier in the spikes of the magnetic brush formed by the magnetic carrier for developing is increased.

The carrier for development has a saturation magnetization of 20 Am ² /
When the weight is less than kg, the carrier easily adheres to the latent image carrier. The saturation magnetization of the carrier for development is 65 Am ² / k
If it exceeds g, the ears will be in a firmly tightened state,
Gradation and reproduction of halftone are reduced.

As described above, the 50% particle size of the developing carrier is preferably from 20 to 50 μm from the viewpoint of developing characteristics.
For the following reasons, in the image forming method using a latent image carrier having a surface layer having a low volume resistance value used in the present invention, the electrostatic latent image formed on the latent image carrier is easily disturbed during development. There is a tendency.

That is, when the particle diameter of the developing carrier becomes smaller, the spikes of the magnetic brush formed by the developing carrier become denser, and the number of contact points of the magnetic brush with the surface of the latent image carrier increases. This is because the phenomenon of charge injection into the surface of the latent image carrier due to the developing bias applied to the developing sleeve during development is likely to occur.

The carrier for development has a saturation magnetization of 20%.
It is preferable to have a magnetic property of about 45 Am ² / kg in terms of developing properties. However, the developing carrier having such magnetic properties increases the density of the developing carrier in the ears of the magnetic brush by the developing carrier, Since the number of contact points with the magnetic brush on the surface of the latent image carrier increases,
For the same reason as above, the electrostatic latent image formed on the latent image carrier tends to be easily disturbed during development.

However, in the present invention, since the volume resistivity of the magnetic carrier for development is high, it is possible to suppress the phenomenon of charge injection into the surface of the latent image carrier during development, and the above-described specific carrier can be obtained. This allows the use of a carrier having a 50% particle size and specific magnetic properties.

In the present invention, when a two-component developer is prepared by mixing a carrier and a toner, the mixing ratio is 1 to 15% by weight, preferably 3 to 15% by weight, as the toner concentration in the two-component developer. 12% by weight, more preferably 5 to
Good results are usually obtained at 10% by weight.

When the toner density is less than 1% by weight, the image density tends to be low. When the toner concentration exceeds 15% by weight, fog and scattering in the machine are increased, and the useful life of the two-component developer is shortened.

In the present invention, when an image is formed using a one-component developer, the function of the carrier is imparted to the developer carrier.

The volume resistivity of the surface layer of the developer carrier used in the present invention is preferably from 10 ⁹ to 10 ¹⁵ Ω · cm, and more preferably from 10 ¹³ to 10 ¹⁵ Ω · cm.

When the volume resistivity of the surface layer of the developer carrier is 10
If it is less than ⁹ Ω · cm, since the resistance is low, a developing bias is injected in the developing region, and the latent image is disturbed.
When the volume resistance value of the surface layer of the developer carrying member exceeds 10 ¹⁵ Ω · cm, the developability of the toner is extremely deteriorated, and image density unevenness is likely to occur.

As a developing method using the toner of the present invention, for example, development can be carried out using a developing means as shown in FIG. Specifically, it is preferable to perform development in a state where the magnetic brush is in contact with the latent image carrier, for example, the photosensitive drum 1 while applying an alternating electric field. The distance (S-D distance) B between the developer carrier (developing sleeve) 11 and the photosensitive drum 1 is preferably 100 to 800 [mu] m in order to prevent carrier adhesion and improve dot reproducibility. 1
If it is smaller than 00 μm, the supply of the developer tends to be insufficient, and the image density becomes low.
_The lines of magnetic force from ₁ widen and the density of the magnetic brush decreases,
The dot reproducibility is poor, and the force for restraining the magnetic coated carrier is weakened, and carrier adhesion is likely to occur.

The voltage between the peaks of the alternating electric field is 300 to 30.
00V is preferable, the frequency is 500 to 10000 Hz,
Preferably, it is 1000-7000 Hz, and each can be appropriately selected and used depending on the process. In this case, the waveform may be triangular, rectangular, sine, or D
Various waveforms with different duty ratios, intermittent alternating superposed electric fields, and the like can be selected and used. If the applied voltage is lower than 300 V, it may be difficult to obtain a sufficient image density, and it may not be possible to satisfactorily collect fog toner in the non-image area. If the voltage exceeds 5000 V, the latent image may be disturbed via the magnetic brush, which may cause deterioration in image quality.

By using a two-component developer having a well-charged toner, the fog removal voltage (Vback) can be reduced.
And the primary charge of the photoconductor can be reduced, so that the life of the photoconductor can be extended. Vbac
k is preferably 200 V or less, more preferably 150 V or less, depending on the developing system.

The contrast potential is preferably from 100 V to 400 V so that a sufficient image density can be obtained.

When the frequency is lower than 500 Hz, although it depends on the process speed, when the toner in contact with the electrostatic image carrier is returned to the developing sleeve, sufficient vibration is not applied and fog is liable to occur. When the frequency exceeds 10,000 Hz, the toner cannot follow the electric field, and the image quality is liable to be deteriorated.

What is important in the developing method of the present invention is that the magnetic brush on the developing sleeve 11 must be in contact with the photosensitive drum 1 in order to obtain sufficient image density, have excellent dot reproducibility, and perform development without carrier adhesion. The contact width (development nip C) is preferably set to 3 to 8 mm. Development nip C is 3
If it is smaller than 8 mm, it is difficult to sufficiently satisfy sufficient image density and dot reproducibility. If it is larger than 8 mm, packing of the developer occurs, which stops the operation of the machine and sufficiently suppresses carrier adhesion. It becomes difficult. As a method of adjusting the developing nip, the distance A between the developer regulating member 15 and the developing sleeve 11 may be adjusted, or the developing sleeve 1 may be adjusted.
The nip width is appropriately adjusted by adjusting the distance B between the photosensitive drum 1 and the photosensitive drum 1.

The image forming method of the present invention uses the developer and the developing method of the present invention, particularly in the case of outputting an image in which the emphasis is placed on halftone, by combining with the developing system in which a digital latent image is formed. There is no influence of the charge injection through the dot and the latent image is not disturbed, so that the dot latent image can be developed faithfully. Also in the transfer step, a high transfer rate can be achieved by using a fine-particle-cut toner having a sharp particle size distribution, so that high image quality can be achieved in both the halftone portion and the solid portion.

Furthermore, by using the two-component developer of the present invention together with the initial improvement of image quality, the change in the amount of charge of the toner in the developing device is small, and the image quality of the present invention does not deteriorate even when copying a large number of sheets. The effect of can be fully exhibited.

In order to obtain a tighter full-color image, a developing device for magenta, cyan, yellow, and black is preferably provided, and a tighter image is obtained by performing black development last. be able to.

An image forming method according to the present invention will be described with reference to the accompanying drawings.

In FIG. 1, a magnetic brush made of magnetic particles 23 is formed on the surface of the transfer sleeve 22 by the magnetic force of the magnet roller 21, and the magnetic brush contacts the surface of the electrostatic image carrier (photosensitive drum) 1. Then, the photosensitive drum 1 is charged. A charging bias is applied to the transport sleeve 22 by a bias applying unit (not shown). By irradiating the charged photosensitive drum 1 with laser light 24 by an exposure device (not shown), a digital electrostatic charge image is formed. The electrostatic charge image formed on the photosensitive drum 1 includes a magnet roller 12 and a developer 19 carried on a developing sleeve 11 to which a developing bias is applied by a bias applying device (not shown).
It is developed by the toner 19a inside.

The developing device 4 includes a partition 17 and a developer chamber R.
_1, is divided into the stirring chamber R _2, respectively developer conveying screw 13, 14 is installed. Above the stirring chamber R _2, a toner storage chamber R ₃ containing a replenishing toner 18 is installed, supply opening 20 is provided in a lower portion of the storage chamber R _3.

The developer transport screw 13 rotates to transport the developer in the developer chamber R1 in _one direction along the longitudinal direction of the developing sleeve 11 while stirring. The partition 17 is provided with openings (not shown) on the near side and the back side in the drawing, and the developer conveyed to _one of the developer chambers R1 by the screw 13 passes through the opening of the partition 17 on one side. The developer is sent to the stirring chamber R ₂ and transferred to the developer transport screw 14. In the direction of rotation the screw 13 opposite the screw 14, the developer in the stirring chamber R _2, the developer chamber R ₁
Stirring the toner supplied from the passed developer and toner storage chamber R ₃ from, with mixing, the screw 13 and conveyed in the stirring chamber R ₂ in the opposite direction, through the other opening of the partition wall 17 sent into the developer chamber R _1.

[0190] To develop the electrostatic latent image formed on the photosensitive drum 1, the developer 19 in the developer chamber R ₁ is drawn up by the magnetic force of the magnet roller 12, the developing sleeve 1
1 is carried on the surface. The developer carried on the developing sleeve 11 is conveyed to the regulating blade 15 with the rotation of the developing sleeve 11, where it is regulated to a thin developer layer having an appropriate layer thickness. To the development area opposed to it. The portion corresponding to the developing area of the magnet roller 12, the magnetic poles are (developing pole) N ₁ is positioned, the developing pole N ₁ forms a developing magnetic field in the developing area,
This developer magnetic field causes the developer to spike, and a magnetic brush of the developer is generated in the development area. Then, the magnetic brush contacts the photosensitive drum 1, and the toner adhered to the magnetic brush and the toner adhered to the surface of the developing sleeve 11 are transferred to the electrostatic image area on the photosensitive drum 1 by the reversal developing method. Then, the electrostatic image is developed to form a toner image.

The developer that has passed through the developing area is returned into the developing device 4 as the developing sleeve 11 rotates, and the magnetic pole S
Due to the repelling magnetic field between S ₁ and S ₂ , it is peeled off from the developing sleeve 11 and falls into the developer chamber R ₁ and the stirring chamber R ₂ to be collected.

By the above development, the developer 1 in the developing device 4
T / C ratio of 9 (toner and mixing ratio of the carrier, i.e., toner concentration in the developer) When decreases is, the agitation chamber R in an amount that was seen from the toner storage chamber R ₃ to the amount consumed toner 18 in the developing ₂ and the T / C of the developer 19 is maintained at a predetermined amount. To detect the T / C ratio of the developer 19 in the container 4,
A toner concentration detection sensor that measures a change in the magnetic permeability of the developer using the inductance of the coil is used. The toner concentration detection sensor has a coil (not shown) therein.

The regulating blade 15 disposed below the developing sleeve 11 and regulating the layer thickness of the developer 19 on the developing sleeve 11 is a non-magnetic blade 15 made of a non-magnetic material such as aluminum or SUS316. The distance between the end and the surface of the developing sleeve 11 is 300 to 1000 μm.
m, preferably 400 to 900 μm. If the distance is less than 300 μm, the magnetic carrier is clogged during this time, and the developer layer is likely to be uneven, and it is difficult to apply the developer necessary for good development, and a developed image having a low density and many unevenness is formed. Easy to be. This distance is preferably 400 μm or more in order to prevent non-uniform application (so-called blade jam) due to unnecessary particles mixed in the developer. If it is larger than 1000 μm, the amount of the developer applied on the developing sleeve 11 increases, and it is difficult to regulate a predetermined thickness of the developer layer. As a result, the adhesion of the magnetic carrier particles to the photosensitive drum 1 increases and the circulation and regulation of the developer. The regulation of development by the blade 15 is weakened, so that toner tribo is reduced and fogging is likely to occur.

Even when the developing sleeve 11 is driven to rotate in the direction of the arrow, the magnetic carrier particle layer is separated from the surface of the sleeve by the balance between the restraining force based on magnetic force and gravity and the conveying force in the moving direction of the developing sleeve 11. Movement slows down. Some fall under the influence of gravity.

Accordingly, by appropriately selecting the arrangement positions of the magnetic poles N and N and the fluidity and magnetic characteristics of the magnetic carrier particles, the magnetic carrier particle layer becomes closer to the sleeve so that the magnetic pole N ₁ becomes closer to the sleeve.
To form a moving layer. Due to the movement of the magnetic carrier particles, the developer is conveyed to the developing area with the rotation of the developing sleeve 11 and is used for development.

Further, the developed toner image is transferred onto a transfer material (recording material) 25 conveyed by a bias applying means 2.
The toner image transferred by the transfer blade 27 as a transfer unit to which a transfer bias is applied by 6 and transferred onto the transfer material is fixed to the transfer material by a fixing device (not shown). In the transfer step, the transfer residual toner remaining on the photosensitive drum 1 without being transferred to the transfer material is adjusted in charge in the charging step, and is collected during development.

FIG. 3 is a schematic diagram in which the image forming method of the present invention is applied to a full-color image forming apparatus.

The main body of the full-color image forming apparatus includes a first image forming unit Pa, a second image forming unit Pb,
An image forming unit Pc and a fourth image forming unit Pd are provided side by side, and images of different colors are formed on a transfer material through a process of forming, developing, and transferring a latent image.

The structure of each image forming unit provided in the image forming apparatus will be described by taking the first image forming unit Pa as an example.

The first image forming unit Pa has a diameter of 30 with a surface layer whose resistance is adjusted as an electrostatic image carrier.
mm is provided, and the photosensitive drum 61a is rotated in the direction of arrow a. 62a
Is a primary charger as a charging means, and a magnetic brush formed on the surface of a sleeve having a diameter of 16 mm
1a is arranged so as to be in contact with the surface. 67a
Is a laser beam for forming an electrostatic charge image on the photosensitive drum 61a whose surface is uniformly charged by the primary charger 62a, and is irradiated by an exposure device (not shown). Reference numeral 63a denotes a developing device as developing means for developing a static charge image carried on the photosensitive drum 61a to form a color toner image, and holds a color toner. Reference numeral 64a denotes a transfer blade as transfer means for transferring the color toner image formed on the surface of the photosensitive drum 61a to the surface of a transfer material (recording material) conveyed by a belt-shaped transfer material carrier 68. The transfer blade 64a can apply a transfer bias by contacting the back surface of the transfer material carrier 68.

In the first image forming unit Pa, after the photosensitive drum 61a is uniformly and primarily charged by the primary charger 62a, an electrostatic image is formed on the photosensitive member by the exposure device 67a, and the electrostatic image is formed by the developing device 63a. Is developed using a color toner, and the developed toner image is transferred to a back surface side of a belt-shaped transfer material carrier 68 which carries and conveys the transfer material at a first transfer portion (a contact position between the photoconductor and the transfer material). A transfer bias is applied from a transfer blade 64a that comes into contact with the transfer member to transfer the image onto the surface of the transfer material.

When the toner is consumed by the development and the T / C ratio decreases, the decrease is detected by a toner concentration detection sensor 85 for measuring a change in the magnetic permeability of the developer using the inductance of the coil, and the toner is consumed. The supply toner 65 is supplied according to the toner amount. The toner density detection sensor 85 has a coil (not shown) therein.

The present image forming apparatus has the same configuration as the first image forming unit Pa, and has the second image forming unit Pb, the third image forming unit Pc, and the third image forming unit Pc having different colors of the color toner held in the developing device. Four image forming units of the fourth image forming unit Pd are provided side by side. For example, yellow toner is used for the first image forming unit Pa, magenta toner is used for the second image forming unit Pb, cyan toner is used for the third image forming unit Pc, and black toner is used for the fourth image forming unit Pd. The transfer of each color toner onto the transfer material is sequentially performed in the transfer section of each image forming unit. In this step, while the registration is being performed, each color toner is superimposed on the same transfer material by one transfer of the transfer material, and when the transfer is completed, the transfer material is separated from the transfer material carrier 68 by the separation charger 69. The sheet is sent to the fixing device 70 by a conveying means such as a conveying belt, and the final full-color image is obtained by a single fixing.

The fixing device 70 has a pair of a fixing roller 71 having a diameter of 40 mm and a pressure roller 72 having a diameter of 30 mm. The fixing roller 71 has heating means 75 and 76 inside.

The unfixed color toner image transferred onto the transfer material passes through a pressure contact portion between the fixing roller 71 and the pressure roller 72 of the fixing device 70, and is applied to the transfer material by the action of heat and pressure. Is established.

In FIG. 3, the transfer material carrier 68 is an endless belt-shaped member, which is moved in the direction of arrow e by a driving roller 80. 7
9 is a transfer belt cleaning device, 81 is a belt driven roller, and 82 is a belt static eliminator. 8
Reference numeral 3 denotes a pair of registration rollers for conveying the transfer material in the transfer material holder to the transfer material carrier 68.

As the transfer means, contact transfer in which a transfer bias can be directly applied by contacting the back surface of a transfer material carrier such as a roller-shaped transfer roller instead of the transfer blade contacting the back surface of the transfer material carrier. Means can be used.

Further, a non-contact type in which a transfer bias is applied from a corona charger arranged in a non-contact manner on the back side of a generally used transfer material carrier in place of the above-mentioned contact transfer means to perform transfer. May be used.

However, it is more preferable to use the contact transfer means in that the amount of ozone generated when the transfer bias is applied can be controlled.

Next, an example of another image forming method of the present invention will be described with reference to FIG.

FIG. 4 is a schematic diagram showing an example of an image forming apparatus capable of performing the image forming method of the present invention.

This image forming apparatus is configured as a full-color copying machine. As shown in FIG. 4, the full-color copying machine has a digital color image reader unit 35 at the upper part and a digital color image printer unit 36 at the lower part.

In the image reader section, the original 30 is placed on an original table glass 31 and is exposed and scanned by an exposure lamp 32 so that a reflected light image from the original 30 is condensed on a full-color sensor 34 by a lens 33, and a color image is formed. Obtain a decomposed image signal. The color-separated image signal is processed by a video processing unit (not shown) through an amplifier circuit (not shown) and sent to a digital image printer unit.

In the image printer section, the photosensitive drum 1, which is an electrostatic image carrier, is a photosensitive body such as an organic photoconductor, and is rotatably carried in the direction of the arrow. Around the photosensitive drum 1, a pre-exposure lamp 11, a corona charger 2 as a primary charging member, a laser exposure optical system 3 as a latent image forming means, a potential sensor 12, and four developing devices 4Y and 4C of different colors. , 4M, 4K, on-drum light amount detecting means 1
3. The transfer device 5A and the cleaning device 6 are arranged.

In the laser exposure optical system 3, an image signal from the reader section is converted into an optical signal for image scan exposure by a laser output section (not shown), and the converted laser light is reflected by the polygon mirror 3a. Is projected on the surface of the photosensitive drum 1 via the lens 3b and the mirror 3c.

When an image is formed, the photosensitive drum 1
Is rotated in the direction of the arrow, and after the charge is eliminated by the pre-exposure lamp 11, the photosensitive drum 1 is uniformly negatively charged by the charger 2 to irradiate a light image E for each separation color, and the latent image is formed on the photosensitive drum 1. To form

Next, the latent image on the photosensitive drum 1 is developed by operating a predetermined developing device, and a visible image, that is, a toner image is formed on the photosensitive drum 1 by a negatively chargeable toner having a resin as a base material. I do. The developing units 4Y, 4C, 4M, and 4K alternately approach the photosensitive drum 1 in accordance with the respective separation colors and perform development by the operation of the eccentric cams 24Y, 24C, 24M, and 24K.

The transfer device 5A includes a transfer drum 5, a transfer charger 5b, a suction charger 5c for electrostatically attracting a recording material and a suction roller 5g opposed thereto, an inner charger 5d, an outer charger 5e, It has a separation charger 5h.
The transfer drum 5 is rotatably supported so as to be rotatable, and a transfer sheet 5f, which is a recording material carrier for supporting a recording material (transfer material) in an opening area around the transfer drum 5, is integrally adjusted in a cylindrical shape. A polycarbonate film or the like is used for the transfer sheet 5f.

The recording material is conveyed from the recording material cassette 7a, 7b or 7c to the transfer drum 5 through the recording material conveyance system, and is carried on the transfer sheet 5f. Transfer drum 5
The recording material carried thereon is repeatedly conveyed to a transfer position facing the photosensitive drum 1 as the transfer drum 5 rotates, and is transferred onto the photosensitive material by the action of the transfer charger 5b while passing through the transfer position. 1 is transferred.

[0220] The above-mentioned image forming step is performed by using yellow (Y),
By repeating the process for magenta (M), cyan (C), and black (K), a color image in which four color toner images are superimposed and transferred on the recording material on the transfer drum 5 is obtained.

In the case of single-sided image formation, the recording material onto which the toner images of four colors have been transferred in this manner is separated by the action of the separation claw 8a, the separation push-up roller 8b, and the separation charger 5h.
The sheet is separated from the transfer drum 5 and sent to the heat fixing device 9.
The heat fixing device 9 includes a heat fixing roller 9a having a heating unit therein and a pressure roller 9b. The full-color image carried on the recording material is fixed on the recording material by passing the recording material through the pressure contact portion between the heat fixing roller 9a and the pressure roller 9b as a heating member. That is, in this fixing step, toner color mixing, color development, and fixing to the recording material are performed to form a full-color permanent image, which is then discharged to the tray 10 to complete one full-color copy. On the other hand, the photosensitive drum 1 is subjected to the image forming process again after the residual toner on the surface is cleaned and removed by the cleaning device 6.

In the image forming method of the present invention, it is possible to transfer a toner image obtained by developing the electrostatic image formed on the latent image carrier to a recording material via an intermediate transfer member.

That is, in this image forming method, the toner image formed by developing the electrostatic image formed on the electrostatic image carrier is transferred to the intermediate transfer member, and the toner image transferred to the intermediate transfer member is developed. Is transferred to a recording material.

With reference to FIG. 5, an example of an image forming method using an intermediate transfer member will be specifically described.

In the apparatus system shown in FIG. 5, the cyan developing device 54-1, the magenta developing device 54-2, the yellow developing device 54-3, and the black developing device 54-4 have a cyan developer and a magenta A magenta developer having a toner, a yellow developer having a yellow toner, and a black developer having a black toner have been introduced. An electrostatic latent image is formed on a photosensitive member 51 as a latent image holding member by a latent image forming means 53 such as a laser beam. By a developing method such as a magnetic brush developing method, a non-magnetic one-component developing method or a magnetic jumping developing method,
The electrostatic charge image formed on the photoconductor 51 is developed with these developers, and a toner image of each color is formed on the photoconductor 51.
The photosensitive member 51 is a photosensitive drum or a photosensitive belt having a conductive substrate 51b and a photoconductive insulating material layer 51a such as amorphous selenium, cadmium sulfide, zinc oxide, an organic photoconductor, and amorphous silicon formed on the conductive substrate 51b. is there. The photoconductor 51 is rotated in a direction indicated by an arrow by a driving device (not shown). As the photoconductor 51, a photoconductor having an amorphous silicon photosensitive layer or an organic photosensitive layer is preferably used.

The organic photosensitive layer may be a single layer type in which the photosensitive layer contains a charge generating substance and a substance having charge transporting ability in the same layer, or a functional separation type in which the charge transporting layer is composed of the charge generating layer as a component. It may be a photosensitive layer. A laminated photosensitive layer having a structure in which a charge generation layer and then a charge transport layer are laminated on a conductive substrate in this order is one of preferred examples.

As the binder resin for the organic photosensitive layer, a polycarbonate resin, a polyester resin, or an acrylic resin has good cleaning properties, and poor cleaning, fusion of a toner to a photoreceptor, and filming of an external additive hardly occur.

In the charging step, there are a non-contact type with the photoreceptor 51 using a corona charger and a contact type with a contact charging member such as a roller, and both types are used. For efficient uniform charging, simplification, and low ozone generation, a contact type as shown in FIG. 5 is preferably used.

A charging roller 52 as a primary charging member is
Conductive elastic layer 5 having central core 52b and outer periphery thereof
2a as a basic configuration. Charging roller 52
Is pressed against the surface of the photoconductor 51 with a pressing force, and the photoconductor 5
The rotation follows the rotation of 1.

[0230] As a preferable process condition when the charging roller is used, the contact pressure of the roller is 5 to 500 g / cm.
In the case where a DC voltage with an AC voltage superimposed thereon is used, an AC voltage = 0.5 to 5 kVpp and an AC frequency = 50
Hz to 5 kHz, DC voltage = ± 0.2 to ± 5 kV.

Other contact charging members include a method using a charging blade and a method using a conductive brush. These contact charging members are effective in that high voltage is not required and generation of ozone is reduced.

The material of the charging roller and the charging blade as the contact charging member is preferably conductive rubber, and a release coating may be provided on the surface thereof. As the release coating, a nylon resin, PVDF (polyvinylidene fluoride), PVDC (polyvinylidene chloride), or a fluorine acrylic resin can be used.

The toner image on the photoreceptor is applied with a voltage (for example, ±
(0.1 to ± 5 kV). The intermediate transfer member 55 includes a pipe-shaped conductive core 55b and a medium-resistance elastic layer 55 formed on the outer peripheral surface thereof.
a. The cored bar 55b may be provided with a conductive layer (for example, conductive plating) on the surface of plastic.

The medium resistance elastic layer 55a is made of silicone rubber, Teflon rubber, chloroprene rubber, urethane rubber,
EPDM (terpolymer of ethylene propylene diene)
A conductive material such as carbon black, zinc oxide, tin oxide, or silicon carbide is mixed and dispersed in an elastic material such as to adjust the electric resistance (volume resistivity) to a medium resistance of 10 ⁵ to 10 ¹¹ Ω · cm. It is a solid or foamed layer.

The intermediate transfer member 55 is arranged in parallel with the photosensitive member 51 so as to be in contact with the lower surface of the photosensitive member 51, and is arranged in the counterclockwise direction indicated by an arrow at the same peripheral speed as the photosensitive member 51. Rotate.

The first color toner image formed and carried on the surface of the photosensitive member 51 is transferred by the transfer bias applied to the intermediate transfer member 55 in the process of passing through the transfer nip where the photosensitive member 51 and the intermediate transfer member 55 are in contact. The intermediate transfer is sequentially performed on the outer surface of the intermediate transfer body 55 by the electric field formed in the nip area.

The untransferred toner on the photosensitive member 51 that has not been transferred to the intermediate transfer member 55 is removed by the photosensitive member cleaning member 5.
8 and is collected in the photoconductor cleaning container 59.

A transfer means is provided in parallel with the intermediate transfer body 55 and is brought into contact with the lower surface of the intermediate transfer body 55. The transfer means 57 is, for example, a transfer roller or a transfer belt. It rotates clockwise with the same peripheral speed as the arrow. The transfer means 57 may be provided so as to directly contact the intermediate transfer body 55, or a belt or the like may be provided so as to contact between the intermediate transfer body 55 and the transfer means 57.

In the case of the transfer roller, the transfer roller is basically composed of a central core bar 57b and a conductive elastic layer 57a formed on the outer periphery thereof.

A general material can be used for the intermediate transfer member and the transfer roller. By setting the volume resistivity of the elastic layer of the transfer roller smaller than the volume resistivity of the elastic layer of the intermediate transfer body, the voltage applied to the transfer roller can be reduced, and a good toner image can be formed on the transfer material. In addition, it is possible to prevent the transfer material from being wound around the intermediate transfer member. In particular, it is particularly preferable that the volume resistivity of the elastic layer of the intermediate transfer member is at least 10 times the volume resistivity of the elastic layer of the transfer roller.

The hardness of the intermediate transfer member and the transfer roller is determined by JI
It is measured according to SK-6301. The intermediate transfer member used in the present invention is preferably composed of an elastic layer belonging to the range of 10 to 40 degrees. On the other hand, the hardness of the elastic layer of the transfer roller is higher than the hardness of the elastic layer of the intermediate transfer member.
Those having a value of from -80 degrees are preferred in order to prevent the transfer material from winding around the intermediate transfer member. When the hardness of the intermediate transfer member and that of the transfer roller are reversed, a concave portion is formed on the transfer roller side, and the winding of the transfer material around the intermediate transfer member is likely to occur.

The transfer means 57 rotates the intermediate transfer member 55 at a constant speed or at a different peripheral speed. The transfer material 56 is conveyed between the intermediate transfer body 55 and the transfer means 57,
The toner image on the intermediate transfer body 55 is transferred to the surface of the transfer material 56 by applying a bias having a polarity opposite to the frictional charge of the toner to the transfer unit 57 from the transfer bias unit.

The untransferred toner remaining on the intermediate transfer member that has not been transferred to the transfer material 56 is removed by the cleaning member 6 for the intermediate transfer member.
0 and is collected in the intermediate transfer body cleaning container 62. The toner image transferred to the transfer material 56 is fixed on the transfer material 56 by the heat fixing device 61.

As the material of the transfer roller, the same material as that of the charging roller can be used. The preferable transfer process condition is that the contact pressure of the roller is 2.94 to 490.
N / m (3 to 500 g / cm) (more preferably, 19.
6 to 294 N / m), DC voltage = ± 0.2 to ± 10 k
V.

If the linear pressure as the contact pressure is less than 2.94 N / m, it is not preferable because the transfer of the transfer material and the occurrence of transfer failure tend to occur.

For example, the conductive elastic layer 5 of the transfer roller 57
7b is an elastic material such as polyurethane rubber or EPDM (ethylene propylene diene terpolymer) mixed with a conductivity-imparting agent such as carbon black, zinc oxide, tin oxide, and silicon carbide to disperse the electric resistance (volume resistance). ) From 10 ⁶
It is a solid or foamed layer adjusted to have a medium resistance of 10 ¹⁰ Ω · cm.

A preferred embodiment of the latent image carrier (photosensitive drum 190) used in the present invention will be described below with reference to FIG.

As the conductive substrate 191, a cylindrical cylinder and a film are used. The conductive substrate may be made of a metal such as aluminum or stainless steel, an alloy such as an aluminum alloy or an indium oxide-tin oxide alloy, a plastic having a coating layer of such a metal or an alloy, a paper or a plastic impregnated with conductive particles, or a conductive material. Formed by a plastic having a conductive polymer.

On the conductive substrate 191, the photosensitive layer 1
92 is provided with an undercoat layer for the purpose of improving adhesiveness, improving coatability, protecting the substrate, covering defects on the substrate, improving charge injection from the substrate 191 and protecting the photosensitive layer 192 against electrical breakdown. Is also good.

The undercoat layer may be made of polyvinyl alcohol, poly-N-vinylimidazole, polyethylene oxide, ethyl cellulose, methyl cellulose, nitrocellulose, ethylene-acrylic acid copolymer, polyvinyl butyral, phenolic resin, casein, polyamide, copolymerized nylon, glue, Formed by gelatin, polyurethane and aluminum oxide. The film thickness is usually 0.
It is preferably about 1 to 10 μm, and more preferably about 0.1 to 3 μm.

The charge generation layer is made of an azo pigment, a phthalocyanine pigment, an indigo pigment, a perylene pigment, a polycyclic quinone face, a squarylium dye, a pyrylium salt, a thiopyrium salt, a triphenylmethane dye, selenium or amorphous silicon. Such an inorganic charge generating material is formed by dispersing and coating an appropriate charge generating layer binder resin, or by vapor deposition.

The binder resin for the charge generation layer can be selected from a wide range of binder resins. For example, polycarbonate resin, polyester resin, polyvinyl butyral resin, polystyrene resin, acrylic resin, methacryl resin, phenol resin, silicone resin, epoxy resin Resins, and vinyl acetate resins.

The amount of the binder resin contained in the charge generation layer is not more than 80% by weight, preferably 0 to 40% by weight. The thickness of the charge generation layer is 5 μm or less, particularly 0.05 to 2 μm.
Is preferred.

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 material in a solvent together with a binder resin for a charge transport layer, if necessary, and applying the solution.
m is good. Examples of the charge transport material include polycyclic aromatic compounds having a biphenylene, anthracene, pyrene or phenanthrene structure in the main chain or side chain; nitrogen-containing cyclic compounds such as indole, carbazole, oxadiazole and pyrazoline; hydrazone compounds; styryl Compounds: inorganic compounds of selenium, selenium-tellurium, amorphous silicon or cadmium sulfide.

Examples of the binder resin for the charge transport layer in which these charge transport substances are dispersed include polycarbonate resin, polyester resin, polymethacrylate, polystyrene resin, acrylic resin, polyamide resin, and poly-N-vinylcarbazole and polyvinylanthracene. And organic photoconductive polymers.

The photoreceptor used in the present invention has a charge injection layer 193 as a layer farthest from the support, that is, a surface layer 192. The volume resistance of the charge injection layer 193 is set to 1 × 10 ⁸ Ω · cm to 1 × 10 ¹⁵ Ω · in order to obtain sufficient chargeability and to prevent image deletion.
cm, preferably 1 × 10 ⁸ Ω · cm to 1 × 10 ¹⁴ Ω · cm
cm, particularly from the viewpoint of image deletion, more preferably 1 × 10 ¹⁰ Ω · cm to 1 × 10 ¹⁵ Ω · cm,
More preferably, 1 × 10 ¹⁰ Ω · cm to 1 × 10 ¹⁴ Ω · cm
cm, more preferably 1 × 10 ¹⁰ Ω · cm to 1 × 10 ¹³ Ω in consideration of environmental fluctuations and the like.
・ It is good to be cm. If it is less than 1 × 10 ⁸ Ω · cm, the charged charge is not held in the surface direction in a high humidity environment, so that image flow may easily occur. If it exceeds 1 × 10 ¹⁵ Ω · cm, the charged charge from the charging member is sufficient. It cannot be injected and held, and tends to cause poor charging.

By providing such a functional layer on the surface of the photoreceptor, it plays a role of retaining the charged charge injected from the charging member, and plays a role of releasing this charge to the support of the photoreceptor at the time of light exposure. To reduce.

In the present invention, by using the above-mentioned specific charging member and the above-mentioned specific photoreceptor in combination,
The charging start voltage Vth is small, and the photosensitive member charging potential can be converged to almost 90% or more of the voltage applied to the charging member.

For example, the absolute value of the charging member is 100 to 20.
When a DC voltage of 00 V is applied at a process speed of 1000 mm / min or less, the charging potential of the electrophotographic photoreceptor having the charge injection layer of the present invention can be 80% or more, and more preferably 90% or more of the applied voltage. . On the other hand, the charging potential of the photosensitive member obtained by the conventional charging using the discharge is about 30% when the applied voltage is 700 V DC.
It was only 200V.

The charge injection layer 193 is composed of an inorganic layer of a metal deposition film or a conductive fine particle resin dispersion layer in which conductive fine particles are dispersed in a binder resin for a charge injection layer. The conductive fine particle resin dispersion film is formed by applying an appropriate coating method such as a dipping coating method, a spray coating method, a roll coating method, and a beam coating method. Further, a resin formed by mixing or copolymerizing an insulating binder resin with a resin having high light transmittance and ionic conductivity, or a resin formed of a single resin having a medium resistance and photoconductive properties may be used.

In the case of the conductive fine particle dispersed film, the amount of the conductive fine particles is preferably 2 to 190% by weight based on the binder resin for the charge injection layer.

If the amount of the conductive fine particles is less than 2% by weight, it becomes difficult to obtain a desired volume resistance value. If the amount of the conductive fine particles exceeds 190% by weight, the film strength is reduced, the charge injection layer is easily scraped off, and the life of the photoconductor tends to be shortened.

As the binder resin for the charge injection layer of the charge injection layer 193, polyester, polycarbonate, acrylic resin, epoxy resin, phenol resin, or a curing agent of these resins may be used alone or in combination of two or more. Further, when dispersing a large amount of conductive fine particles, it is preferable to use a reactive monomer or a reactive oligomer, disperse the conductive fine particles, apply to the surface of the photoreceptor, and then cure by light or heat. .

When the photosensitive layer 192 is made of amorphous silicon, the charge injection layer 193 is preferably made of SiC.

Examples of the conductive fine particles dispersed in the charge injection layer binder resin of the charge injection layer 193 include metals and metal oxides. Preferably, ultrafine particles of a metal or metal oxide such as zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, bismuth oxide, tin oxide-coated titanium oxide, tin-coated indium oxide, antimony-coated tin oxide and zirconium oxide are used. is there. These may be used alone or as a mixture of two or more.

In general, when particles are dispersed in the charge injection layer 193, it is necessary that the particle diameter 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. The particle size of the conductive and insulating particles dispersed in the surface layer is preferably 0.5 μm or less.

In the present invention, the charge injection layer 193 preferably contains lubricant particles. The reason is that the friction between the photosensitive member and the charging member during charging is reduced, so that the charging nip is enlarged and the charging characteristics are improved. In particular, it is preferable to use a fluorine resin, a silicone resin or a polyolefin resin having a low critical surface tension as the lubricant particles. More preferably, ethylene tetrafluoride resin (PTF
E) is used. In this case, the amount of the lubricant particles is 2 to 50% by weight, preferably 5 to 40% by weight, based on the binder resin. When the amount is less than 2% by weight, the amount of the lubricant particles is not sufficient, so that the improvement of the charging characteristics is not sufficient.
If it exceeds 0% by weight, the resolution of the image and the sensitivity of the photoreceptor are greatly reduced.

In the present invention, the thickness of the charge injection layer 193 is preferably 0.1 to 10 μm, particularly preferably 1 to 10 μm.
It is preferably 7 μm.

When the film thickness is less than 0.1 μm, resistance to minute scratches is lost, and as a result, image defects due to poor injection are likely to occur. If the film thickness exceeds 10 μm, the image tends to be disturbed due to the diffusion of the injected charges.

In the present invention, fine particles of a fluorine atom-containing resin used for the electrostatic latent image carrier are made of polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, polydichlorodifluoroethylene, tetrafluoroethylene-perfluoroalkylvinyl ether. One or more selected from copolymers, tetrafluoroethylene-hexafluoropropylene copolymers, tetrafluoroethylene-ethylene copolymers, and tetrafluoroethylene-hexafluoropropylene-perfluoroalkylvinyl ether copolymers It consists of. Commercially available fluorine atom-containing resin fine particles can be used as they are. Those having a weight average molecular weight of 30 to 5,000,000 can be used, and the weight average particle diameter is preferably 0.01 to 10 µm, more preferably 0.05 to 2.0 µm.

In many cases, the protective layer and the photosensitive layer are formed by dispersing and containing the above-mentioned fluorine atom-containing resin fine particles, the charge generation material and the charge transport material in a binder resin having film-forming properties. Such binder resins include polyester, polyurethane, polyacrylate, polyethylene,
Polystyrene, polycarbonate, polyamide, polypropylene, polyimide, phenolic resin, acrylic resin, silicone resin, epoxy resin, urea resin, allyl resin, alkyd resin, polyamide-imide, nylon, polysulfone, polyallyl ether, polyacetal, butyral resin .

The conductive support of the electrostatic latent image carrier is made of iron,
Metals and alloys such as copper, gold, silver, aluminum, zinc, titanium, lead, nickel, tin, antimony, indium,
Alternatively, an oxide of the metal, carbon, or a conductive polymer can be used. The shapes include a drum shape such as a cylindrical shape and a cylindrical shape, a belt shape, and a sheet shape. The conductive material may be formed as it is, used as a paint, deposited, or processed by etching or plasma processing.

Further, when the latent image carrier is cylindrical, the diameter (d ₁ ) of the cylindrical latent image carrier and the cylindrical developer carrier which magnetically restrains the developing magnetic carrier are different. the diameter ratio between _{(d 2) (d1 / d} 2) is, it preferably 1.0 to 3.0, more preferably 1.0 to 2.2, more preferably from 1.0 to 2.0 However, since the contact area of the magnetic brush by the developing magnetic carrier with respect to the surface of the latent image carrier is reduced, a charge injection phenomenon due to a developing bias applied during development is likely to occur, and disturbance of the electrostatic latent image can be suppressed. It is more preferable from the viewpoint of compactness of the whole apparatus.

As a contact one-component developing method, it is possible to develop using a non-magnetic toner, for example, using a developing device 90 as shown in FIG.

The developing device 90 carries a developing container 91 containing a one-component developer 98 having a magnetic or non-magnetic toner, and carries the one-component developer 98 stored in the developing container 91, and transports it to the developing area. Roller 92 for supplying developer to developer carrier 92 for supplying toner to developer carrier
5. Elastic blade 96 as a developer layer thickness regulating member for regulating the thickness of the developer layer on the developer carrier, and developing container 9
1 has a stirring member 97 for stirring the developer 98.

As the developer carrier upper surface 92, an elastic layer 9 formed on a roller base 93 by an elastic member such as rubber or resin having elasticity such as foamed silicone rubber.
It is preferred to use an elastic roller having 4.

The elastic roller 92 is pressed against the surface of the photosensitive drum 99 serving as a latent image holding member, and electrostatically formed on the photosensitive member by the one-component developer 98 applied to the surface of the elastic roller. While developing the latent image, an unnecessary one-component developer 98 existing on the photoreceptor after transfer is collected.

In the present invention, the developer carrying member is substantially in contact with the photosensitive member surface. This means that the developer carrier is in contact with the photoconductor when the one-component developer is removed from the developer carrier. At this time, an image having no edge effect can be obtained by an electric field acting between the photoconductor and the developer carrier via the developer, and at the same time, cleaning is performed. There is a need to have an electric potential between the surface of the elastic roller or the vicinity of the surface as a developer carrier and an electric field between the surface of the photosensitive member and the surface of the elastic roller. For this reason,
It is also possible to use a method in which the elastic rubber of the elastic roller is resistance-controlled in the medium resistance region to keep the electric field while preventing conduction with the photoreceptor surface, or a method of providing a thin dielectric layer on the surface layer of the conductive roller. Further, a configuration in which a conductive layer is provided on a surface of the conductive roller which is in contact with the surface of the photoreceptor with a conductive resin sleeve having a surface in contact with the surface of the photoreceptor covered with an insulating material, or a surface of the insulating roller which is not in contact with the photoreceptor. It is possible.

The elastic roller carrying the one-component developer may rotate in the same direction as the photosensitive drum or in the opposite direction. When the rotation is in the same direction, it is preferable that the peripheral speed ratio is greater than 100% with respect to the peripheral speed of the photosensitive drum. If it is less than 100%, problems tend to occur in image quality such as poor line clarity. As the peripheral speed ratio increases, the amount of the developer supplied to the development site increases, and the frequency of desorption of the developer from the electrostatic latent image increases.
An unnecessary portion of the developer is scraped off, and the necessary portion is repeatedly supplied with the developer, whereby an image faithful to the electrostatic latent image is obtained. More preferably, the peripheral speed ratio is 100
% Or more is good.

The developer layer thickness regulating member 96 is not limited to an elastic blade, and may be an elastic roller as long as it is in pressure contact with the surface of the developer carrier 92 by elastic force.

As the elastic blade and the elastic roller, rubber elastic bodies such as silicone rubber, urethane rubber and NBR; synthetic resin elastic bodies such as polyethylene terephthalate; metal elastic bodies such as stainless steel and steel can be used. Further, even a complex thereof can be used.

In the case of an elastic blade, the base on the upper side of the elastic blade is fixed and held on the developer container side, and the lower side is bent in the forward or reverse direction of the developing sleeve against the elasticity of the blade. In this state, the inner surface of the blade (the outer surface in the case of the opposite direction) is brought into contact with the sleeve surface with moderate elastic pressure.

The supply roller 95 is made of a foam material such as a polyurethane foam.
The developer rotates in a forward or reverse direction at a relative speed other than 0, and supplies the one-component developer and also peels off the developed developer (undeveloped developer) on the developer carrier.

When the electrostatic latent image on the photosensitive member is developed with a one-component developer on the developer bearing member in the developing area, a direct and / or alternating current is applied between the developer bearing member and the photosensitive drum. It is preferred to apply a developing bias of to develop.

Next, the non-contact jumping development method will be described.

As the non-contact jumping developing method, there is a developing method using a one-component magnetic developer having a non-magnetic toner.

Here, a developing method using a one-component non-magnetic developer having a non-magnetic toner will be described with reference to the schematic configuration diagram shown in FIG.

The developing device 170 includes a developing container 17 containing a non-magnetic one-component developer 176 having a non-magnetic toner.
1. A developer carrier 172 for carrying the one-component non-magnetic developer 176 contained in the developing container 171 and transporting it to the development area, and supplying the one-component non-magnetic developer on the developer carrier Roller 173 for controlling the thickness, the elastic blade 174 as a developer layer thickness regulating member for regulating the thickness of the developer layer on the developer carrier, and the one-component non-magnetic developer 176 in the developing container 171 are stirred. Stirring member 175 for the purpose.

Reference numeral 169 denotes an electrostatic latent image holding member, and a latent image is formed by an electrophotographic processing means or an electrostatic recording means (not shown). Reference numeral 172 denotes a developing sleeve as a developer carrier, which is made of a non-magnetic sleeve made of aluminum or stainless steel.

As the developing sleeve, a rough tube of aluminum or stainless steel may be used as it is, but preferably, the surface thereof is uniformly roughened by spraying glass beads.
A mirror-finished one or a resin-coated one is preferred.

The one-component non-magnetic developer 176 is used in the developing container 1
The developer is supplied to the developer carrier 172 by a supply roller 173. Supply roller 173
Is made of foam material such as polyurethane foam,
The developer carrier is rotated in a forward or reverse direction at a relative speed other than 0, and the developer is supplied and the developer (undeveloped developer) on the developer carrier 172 after the development is peeled off. ing. The one-component non-magnetic developer supplied onto the developer carrier 172 is uniformly and thinly applied by an elastic blade 174 as a developer layer thickness regulating member.

The contact pressure between the elastic coating blade and the developer carrier is 0.3 to 2 as a linear pressure in the developing sleeve generatrix direction.
5 kg / m, preferably 0.5 to 12 kg / m is effective. When the contact pressure is less than 0.3 kg / m, it is difficult to uniformly apply the one-component non-magnetic developer, and the charge amount distribution of the one-component non-magnetic developer becomes broad, which causes fogging and scattering. When the contact pressure exceeds 25 kg / m, a large pressure is applied to the one-component non-magnetic developer, and the one-component non-magnetic developer is deteriorated. Absent. Further, a large torque is required to drive the developer carrier, which is not preferable. That is, by adjusting the contact pressure to 0.3 to 25 kg / m, it becomes possible to effectively loosen the aggregation of the one-component non-magnetic developer using the toner of the present invention. It is possible to instantly raise the charge amount of the non-magnetic developer.

As the developer layer thickness regulating member, an elastic blade or an elastic roller can be used, and it is preferable to use a material of a triboelectric series suitable for charging the developer to a desired polarity.

In the present invention, silicone rubber, urethane rubber and styrene butadiene rubber are preferred. Furthermore, polyamide, polyimide, nylon, melamine, melamine cross-linked nylon, phenolic resin, fluororesin,
An organic resin layer such as a silicone resin, a polyester resin, a urethane resin, and a styrene resin may be provided. Uses conductive rubber and conductive resin, and further disperses fillers and charge control agents such as metal oxides, carbon black, inorganic whiskers, and inorganic fibers in the rubber and resin of the blade to achieve appropriate conductivity and charging. It is preferable because it gives imparting properties and can appropriately charge the one-component non-magnetic developer.

In this non-magnetic one-component developing method, in a system in which a one-component non-magnetic developer is thinly coated on a developing sleeve by a blade, the one-component non-magnetic developer on the developing sleeve is required to obtain a sufficient image density. It is preferable that the thickness of the non-magnetic developer layer is made smaller than the opposing gap length β between the developing sleeve and the latent image holding member, and an alternating electric field is applied to this gap.
That is, by applying an alternating electric field or a developing bias in which a DC electric field is superimposed on the alternating electric field between the developing sleeve 172 and the latent image holder 169 by the bias power supply 177 shown in FIG. The transfer of the one-component non-magnetic developer to the non-magnetic developer can be facilitated, and a higher quality image can be obtained.

[0296]

EXAMPLES Hereinafter, a specific method for producing a toner, an example,
The present invention will be described in more detail with reference to comparative examples. "Department"
Means "parts by weight".

(Production Example 1 of Toner) Styrene monomer 10
For 0 parts, 16 parts of carbon black (1) [DBP oil absorption 42 ml / 100 g, specific surface area 6.5 m ² / g, average particle diameter 31 mμ, volatile matter 0.5%, pH value 9],
A combination of 1 part of the azo-based iron compound (1) and 1 part of the aluminum compound of di-tert-butylsalicylic acid was prepared. This was added to an attritor (manufactured by Mitsui Mining Co., Ltd.) and stirred at 200 rpm for 180 minutes at 25 ° C. using 2 mm zirconia beads to prepare a master batch dispersion liquid 1 (A / B = 16).

On the other hand, 0.1M
-Na ₃ PO ₄ aqueous solution 450 parts was charged, followed by heating to 60 ° C., and stirred at 12,000rpm using Claire mixer (manufactured by M Technique Co., Ltd.). 1.0MCa
68 parts of a Cl ₂ aqueous solution was gradually added to obtain an aqueous medium containing a calcium phosphate compound.

Next, 117 parts of master batch dispersion liquid, 66 parts of styrene monomer, 34 parts of n-butyl acrylate, 20 parts of ester wax (1), 10 parts of saturated polyester resin, and 0.4 parts of divinylbenzene The mixture was heated to 60 ° C., stirred and uniformly dissolved and dispersed. Into this, 5 parts of a polymerization initiator 2,2′-azobis (2,4-dimethylvaleronitrile) was dissolved to prepare a polymerizable monomer composition.

[0300] Then, maintaining in the aqueous medium to pH 6.8, was charged with the polymerizable monomer composition, 60 ° C., N ₂
Under an atmosphere, the mixture was stirred at 10,000 rpm for 10 minutes with a CLEAR MIXER (manufactured by M Technique Co., Ltd.) to granulate the polymerizable monomer composition. Thereafter, the mixture was transferred to a reaction vessel, the pH in the aqueous medium was maintained at 6.8, and the temperature was raised to 60 ° C. while stirring with a paddle stirring blade, and the reaction was performed for 5 hours. Further, a water-soluble initiator was added, the temperature was raised to 80 ° C., and the reaction was performed for 5 hours. After completion of the polymerization reaction, the remaining monomer was distilled off under reduced pressure, and after cooling, hydrochloric acid was added to dissolve the calcium phosphate compound, followed by filtration, washing with water, drying under vacuum, and classification using a multi-stage classifier. Thus, black toner particles were obtained.

To 98.5 parts by weight of the obtained black toner particles, 0.5 part by weight of hydrophobic titanium oxide having a specific surface area of 100 m ² / g by the BET method, and 40 m ² / g by the BET method Was externally added with a Henschel mixer, and coarse particles were removed with a turbo screener. 1 (weight number average particle size of 7.6 μm, 8 number% of 4 μm or less, 12.7 μm or more of 0.3 volume%) was obtained. a = 11 and b = 19.

As the saturated polyester resin to be added when preparing the polymerizable monomer composition, Mw = 1 obtained by condensing propoxylated bisphenol and terephthalic acid was used.
1000, Mw / Mn = 2.1, acid value 10 mgKOH /
g of polyester resin was used.

(Production Example 2 of Toner) An aqueous medium containing a larger amount of a calcium phosphate compound than that of Production Example 1 was used.
Black toner No. 1 was prepared in the same manner except that the number of revolutions of the Clare mixer was set to 15,000 rpm. 2 (weight average particle size 2.8 μm, 93% by number of 4 μm or less, 12.7
μm or more and 0% by volume). a = 18 and b = 12.

(Toner Production Example 3) Black toner No. 1 was prepared in the same manner as in Production Example 1, except that an aqueous medium containing a smaller amount of a calcium phosphate compound was used, and the rotation speed of the Clea mixer was set to 6500 rpm. 3 (weight-average particle diameter: 10.5 μm, 4 μm or less: 5% by number, 12.
7 μm or more and 21% by volume). a = 15 and b = 15.

(Production Example 4 of Toner)
DBP oil absorption 95ml / 100g, specific surface area 300m ²
/ G, average particle size 11 mμ, volatile content 2%, pH value 9 except that carbon black was used. 4 (weight average particle diameter 7.4 μm, 9% by number of 4 μm or less, 0.8% by volume of 12.7 μm or more). a
= 18, b = 12.

(Production Example 5 of Toner)
DBP oil absorption 123ml / 100g, specific surface area 50m ²
/ G, an average particle diameter of 65 mμ, a volatile content of 0.9%, and a pH value of 9.5 except that carbon black was used. 5 (weight average particle size 7.1μ)
m, 4 μm or less, 16 number%, 12.7 μm or more, 1.6 volume%). a = 16 and b = 14.

(Production Example 6 of Toner)
In the same manner except that no azo-based iron compound was used, the black toner No. 6 (weight average particle size 7.4 μm, 23% by number of 4 μm or less, 23% by volume of 12.7 μm or more).
Although a = 14 and b = 16, it was recognized that carbon black was separated from the toner surface layer.

(Toner Production Examples 7, 8, 9) In Production Example 1, magenta toner No. 1 was prepared by using 16 parts of a quinacridone pigment instead of carbon black. No. 7 using 12 parts of a phthalocyanine pigment and cyan toner No. 8
And 6 parts of CI Pigment Yellow 93 and 6 parts of Solvent Yellow 162. 9 was obtained.

(Production Example of Magnetic Carrier) 50 parts of phenol (hydroxybenzene) 80 parts of 37 wt% formalin aqueous solution 50 parts of water 50 parts of silane coupling agent having epoxy group KBM403 280 parts (Shin-Etsu Chemical Co., Ltd.) Fine particles (number average particle size 0.24 μm, specific resistance value 5 × 10 ⁵ Ω · cm) treated with KBM403 120 parts of α-Fe ₂ O ₃ fine particles surface treated with KBM403 (number average) (Particle diameter: 0.40 μm, specific resistance value: 8 × 10 ⁹ Ω · cm) ・ 25 parts by weight of aqueous ammonia 15 parts The above materials were placed in a four-necked flask, and stirred and mixed.
The temperature was raised to 85 ° C. in 0 minutes, and the reaction and curing were performed for 120 minutes. After cooling to 30 ° C. and addition of 500 parts by weight of water, the supernatant was removed, and the precipitate was washed with water and air-dried. Then, this was reduced to 150 to 180 under reduced pressure (5 mmHg).
After drying at 24 ° C. for 24 hours, a magnetic carrier core (A) using a phenol resin as a binder resin was obtained. The magnetic carrier core (A) has a temperature of 30 ° C./80% for 24 hours, and
t% of adsorbed water was present.

On the surface of the obtained magnetic carrier core (A), γ-aminopropyltrimethoxysilane

[0311]

Embedded image Of a 5% by weight toluene solution was applied.

The surface of the magnetic carrier core (A) is 0.2
It had been treated with γ-aminopropyltrimethoxysilane by weight. During the application, the toluene was volatilized while applying while continuously applying shear stress to the magnetic carrier core (A). On the surface of the magnetic carrier core (A)

[0313]

Embedded image Was confirmed to be present.

While stirring the magnetic carrier (A) treated with the silane coupling agent in the above-mentioned processing machine at 70 ° C.,
Silicone resin KR-221 (Shin-Etsu Chemical Co., Ltd.)
) Was added with 3% of γ-aminopropyltrimethoxysilane based on the solid content of the silicone resin, diluted with toluene so as to have a silicone resin solid content of 20%, and then added under reduced pressure. Resin coating was performed. Thereafter, after stirring for 2 hours, heat treatment was performed at 140 ° C. for 2 hours in an atmosphere of nitrogen gas to loosen aggregation, and coarse particles of 200 mesh or more were removed to obtain a magnetic carrier I.

The obtained magnetic carrier I had an average particle diameter of 3
5 μm, magnetization strength (σ ₁₀₀₀ ) 42 Am ² / k at 1 × 10 ¹³ Ω · cm, 1 Oe
g, the residual magnetization (σ _r ) was 3.1 Am ² / kg, the true specific gravity was 3.71, and the bulk density was 1.87 g / cm ³ .

(Photoreceptor Production Example 1) The photoreceptor is a photoreceptor using an organic photoconductive material for negative charging, and five functional layers are provided on a φ30 mm aluminum cylinder.

The first layer is a conductive layer having a thickness of about 20 μm, which is provided to smooth defects of the aluminum cylinder and to prevent the occurrence of moire due to reflection by laser exposure. It is.

The second layer is a positive charge injection preventing layer (undercoat layer), which serves to prevent the positive charge injected from the aluminum substrate from canceling out the negative charge charged on the surface of the photoreceptor. This is a medium resistance layer having a thickness of about 1 μm, the resistance of which is adjusted to about 10 ⁶ Ω · cm by 66-610-12-nylon and methoxymethylated nylon.

The third layer is a charge generation layer, which is a layer having a thickness of about 0.3 μm in which a disazo pigment is dispersed in a resin, and generates positive and negative charge pairs by being exposed to laser.

The fourth layer is a charge transport layer, in which hydrazone is dispersed in a polycarbonate resin, and is a P-type semiconductor. Therefore, the negative charges charged on the photoreceptor surface cannot move through this layer, and only the positive charges generated in the charge generation layer can be transported to the photoreceptor surface.

The fifth layer is a charge injecting layer, which has a particle diameter of about 0.01 to increase the contact time between the photocurable acrylic resin and the ultrafine particles of SnO ₂ and the charging member and the photoreceptor to achieve uniform charging. It is obtained by dispersing 0.25 μm ethylene tetrafluoride resin particles. Specifically, oxygen-deficient SnO ₂ particles having a reduced particle size of about 0.03 μm and 12
0% by weight, 20% by weight of ethylene tetrafluoride resin particles, and 1.0% by weight of a dispersant.

As a result, the volume resistivity of the surface layer of the photoreceptor 1 was reduced to 8 × 10 ¹¹ Ω · cm, compared with 5 × 10 ¹⁵ Ω · cm for the charge transport layer alone.

(Photoreceptor Production Example 2) Fifth Example of Photoreceptor Production Example 1
The layer was made of an oxygen-deficient type of low resistance SnO ₂ particles having a particle size of about 0.03 μm,
Photoreceptor 2 was prepared in the same manner as in Photoreceptor Production Example 1, except that it was dispersed by weight%.

As a result, the volume resistance value of the photoconductor surface layer was reduced to 8 × 10 ⁷ Ω · cm.

(Photoreceptor Production Example 3)
Photoconductor 3 having a volume resistivity of 5 × 10 ¹⁵ Ω · cm of the surface layer of the photoconductor was prepared in the same manner except that nO ₂ was not used.

(Production Example 1 of Charging Member) 10 parts of MgO, M
After pulverizing 10 parts of nO and 80 parts of Fe ₂ O ₃ , respectively,
After adding and mixing water and granulating, firing at 1300 ° C.,
After adjusting the particle size, a ferrite core material (saturation magnetization 63 Am ² / kg) having an average particle size of 22 μm was obtained.

A mixture obtained by mixing 10 parts of isopropoxytriisostearoyl titanate with 99 parts of toluene and 1 part of water was subjected to a surface treatment on the ferrite core material so as to be 0.1 part. Magnetic particles a having a volume resistivity of 25.5 μm and a volume resistivity of 7 × 10 ⁷ Ω · cm were obtained.

(Production Example 2 of Charging Member) A ferrite core material of Production Example 1 was milled in the same manner except that it was pulverized by a jet mill.
50% particle size 20.5μm, volume resistivity 3 × 10 ⁷ Ω
Cm magnetic particles b were obtained.

(Production Example 3 of Charging Member) In Production Example 1, the 50% particle size was 48.5 μm, and the volume resistance value was 8 × 10
Magnetic particles c were obtained in the same manner except that a ferrite core material of ⁶ Ω · cm was used.

[Example 1] Magnetic carrier I (92 parts by weight) and black toner no. 1 (8 parts by weight) was mixed with a V-type mixer to obtain a two-component black developer 1.

Next, a developing device of a commercially available copying machine GP55 (manufactured by Canon) was modified as shown in FIG. 1, and a SUS sleeve having a diameter of 16 mm was sandblasted as a developing sleeve to have a surface shape of Ra = 2.1 and Sm = 2.1. 25.5
The magnetic member a is used as a charging member using the magnetic brush charger shown in FIG. 1, and is rotated at 120% in the counter direction with respect to the photosensitive member.
An AC electric field (-700 V, 1 kHz / 1.2 kVpp) was superimposed and applied, the photosensitive member 1 was charged, the cleaning unit was removed, and the developing contrast was set at 250 V and the reversal contrast with fog was set at -150 V. Applying a developing bias having an AC electric field and using the above-described black developer 1, 23 ° C./65%, 23 ° C./5%,
Image formation was performed at 2.5 ° C./90%, and continuous copying of 10,000 sheets was performed using an original document having an image area ratio of 30%. At this time, d ₁ / d ₂ was 1.88.

From Table 1, it can be seen that the image forming means described above has a good image quality, a small image change due to continuous copying, and a very good fog without any problem.

Incidentally, the image evaluation shown in Table 1 was performed as follows.

(1) Image density: The image density was measured using a Macbeth densitometer PD918 type (Macbeth Densitometer) equipped with an SPI filter.
ETER RD918manufacturd by
Macbeth Co. ) Was measured as the relative density of the image formed on plain paper.

(2) Solid Uniformity An original manuscript provided with five circles each having a diameter of 20 mm and having an image density of 1.5 as measured by a reflection densitometer RD918 (manufactured by Macbeth) was copied, and the image density of the image area was copied. Was measured with a reflection densitometer RD918, and the difference between the maximum value and the minimum value at that time was determined. ◎: 0.04 or less ○: More than 0.04 0.08 or less △: More than 0.08 0.12 or less ×: More than 0.12

(3) Fog suppression The average reflectance Dr (%) of plain paper before image output was measured using a reflectometer (“REFECTOM” manufactured by Tokyo Denshoku Co., Ltd.).
ETER ODEL TC-6DS "). On the other hand, a solid white image was formed on plain paper, and the reflectance Ds (%) of the solid white image was measured. Fog (%)
Is calculated from the following equation: Fog (%) = Dr (%)-Ds (%) A: Less than 0.4% B: 0.4% to less than 0.8% C: 0.8% to less than 1.2% D: 1.2% or more

[Comparative Example 1] In Example 1, the photosensitive member 2
When image formation was carried out in the same manner except for using, the image density was lowered particularly under high humidity, and the solid uniformity was lowered. This is presumably because the volume resistance of the photoconductor surface layer was too low, and the latent image charge was disturbed via the toner surface.

[Comparative Example 2] In Example 1, the photosensitive member 3
When image formation was performed in the same manner except for using, the fog suppression was poor, and image ghosting occurred in the photoconductor cycle. This is presumably because the photoconductor surface layer had a high volume resistance and the charging ability by injection was insufficient.

[Comparative Example 3] Toner N in Example 1
o. Image formation was carried out in the same manner except that No. 2 was used. As a result, the image density was lowered and the fog suppression was deteriorated.

[Comparative Example 4] Toner N in Example 1
o. When image formation was performed in the same manner except that No.3 was used, suppression of line scattering was deteriorated, and fog suppression was also slightly deteriorated.

[Comparative Example 5] Toner N in Example 1
o. When image formation was performed in the same manner except that No. 4 was used, fog suppression and solid uniformity were both deteriorated, so the durability was stopped. This is presumed to be because the average primary particle size of the carbon black was small, and the carbon black was released on the toner surface.

[Comparative Example 6] Toner N in Example 1
o. When image formation was performed in the same manner except that No. 5 was used, the durability was stopped because the image density was lowered. this is,
It is presumed that the coloring power was reduced due to the large average primary particle size of the carbon black.

[Example 2] Toner N in Example 1
o. After using the same procedure as above except using 6,
Good results were obtained although solid uniformity was slightly deteriorated. This is because the azo iron compound was not used,
It is presumed that the dispersion state of carbon black was slightly reduced.

Example 3 The same procedure as in Example 1 was carried out except that magnetic particles b were used as the charging member, and good results were obtained.

Example 4 The same procedure was carried out except that a conductive rayon brush having a volume resistance of 9 × 10 ⁷ Ω · cm was used as a charging member. Obtained.

Example 5 As a charging member, magnetic particles c
In the same manner as above, good results were obtained although the image density was slightly lowered and fog suppression was slightly deteriorated.

[Embodiment 6] As an image forming apparatus, GP5
5 instead of a commercially available full-color copier CLC240
0 (manufactured by Canon), as shown in FIG. 3, the cleaning unit was eliminated, and the primary charging was changed to a contact charging unit having magnetic particles a. . When images were formed in the same manner except that toners / developers of four colors of 1, 7, 8, and 9 were used, good results were obtained. At this time, the volume resistance value of the photoconductor surface layer was 9 × 10 ¹² Ω · cm, the photoconductor diameter was 60φ, and d ₁ / d ₂ was 3.75.

[Embodiment 7] As shown in FIG. 5, an intermediate transfer drum was used as an image forming apparatus. 1,
As shown in FIG. 7, when the image formation was performed in the same manner except that the toners of four colors 7, 8, and 9 were used in the non-magnetic one-component developing system, good results were obtained. At this time, the volume resistance value of the photoconductor surface layer was 2 × 10 ¹³ Ω · cm, and the photoconductor diameter was 1
40φ, and d ₁ / d ₂ was 8.75.

[Embodiment 8] As shown in FIG. 6, the developing device of GP55 was modified for non-magnetic contact development as shown in FIG.
Toner No. When 1,500 sheets were used to endure 5,000 sheets, good results were obtained. At this time, d ₁ / d ₂ was 1.88.

[0350]

[Table 1]

[0351]

According to the present invention, the present invention can be applied to a cleaner-less system while achieving a high-definition image with a high image density without being affected by temperature and humidity, and is also suitable as a full-color black toner. Can be used.

[Brief description of the drawings]

FIG. 1 is a schematic view illustrating a preferred example of an image forming method of the present invention.

FIG. 2 is a diagram showing an alternating electric field used in Example 1.

FIG. 3 is a schematic explanatory view showing an example of a full-color image forming method.

FIG. 4 is a schematic explanatory view showing another example of the image forming apparatus for performing the image forming method of the present invention.

FIG. 5 is a schematic explanatory view showing another example of the image forming apparatus for performing the image forming method of the present invention.

FIG. 6 is a schematic explanatory view showing another example of an image forming apparatus for performing the image forming method of the present invention.

FIG. 7 is a schematic explanatory view showing another example of the image forming apparatus for performing the image forming method of the present invention.

FIG. 8 shows a schematic diagram of a magnetic brush charger.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 electrostatic image carrier (photosensitive drum) 4 developing device 11 developer carrier (developing sleeve) 12 magnet roller 13, 14 developer transport screw 15 regulating blade 17 partition 18 replenishing toner 19 developer 19 a toner 19 b carrier 20 replenishing Port 21 Magnet roller 22 Transport sleeve 23 Magnetic particles 24 Laser beam 25 Transfer material (recording material) 26 Bias applying means 27 Transfer blade 28 Toner density detection sensor 61a Photosensitive drum 62a Primary charger 63a Developing device 64a Transfer blade 65a Replenishing toner 67a Laser light 68 Transfer material carrier 69 Separation charger 70 Fixer 71 Fixing roller 72 Pressure roller 73 Web 75, 76 Heating means 79 Transfer belt cleaning device 80 Driving roller 81 Belt driven roller 82 Bell G Static eliminator 83 Registration roller 85 Toner density detection sensor 190 Photosensitive drum 191 Base 192 Photosensitive layer 193 Charge injection layer 194 Magnetic brush charger 195 Magnet roller 196 Non-magnetic sleeve 197 Conductive magnetic particles

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 15/02 101 G03G 9/08 346 15/08 112 365 (72) Inventor Yuji Migiri Yoko Shimomaruko, Ota-ku, Tokyo 3-30-2 Canon Inc. (72) Inventor Yasushi Katsuta 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Shinya Taniuchi 3-30, Shimomaruko, Ota-ku, Tokyo No.2 Canon Corporation F-term (reference) 2H003 AA18 BB11 CC04 EE11 2H005 AA06 AA21 AB06 CA14 CA21 CA22 CB18 DA02 EA05 EA07 EA10 FA01 2H030 AB02 BB02 BB23 BB42 BB54 2H068 AA08 AA54 FC01 FC08 AD13 AD07 AD13 AD07 DA10 DA54 EA03 EA15 GA13 GA17

Claims (38)

[Claims] A charging step of charging a latent image carrier by bringing a contact charging means into contact with a latent image carrier for carrying an electrostatic latent image; and an electrostatic latent image on the charged latent image carrier. Forming a latent image forming step, a developing container holding a two-component developer having a toner having toner particles and a magnetic carrier, and carrying the two-component developer held in the developing container; Using a developing device having a developer carrier for conveyance, the electrostatic latent image carried on the latent image carrier is developed in a development area with the toner of the two-component developer to form a toner image. In the image forming method, the surface layer of the latent image carrier has a volume resistance (A) of 10 ⁸ to
10 is a ¹⁴ Omega · cm, the toner is, contains at least a binder resin and carbon black, the weight average particle diameter of the toner is 3 to 10 [mu] m, an average primary particle diameter of the carbon black in 13~60mμ A, and in a dispersed state in the toner, a ≦ b, where a is the number of agglomerates having less than 10 primary particles and b is the number of agglomerates having 10 or more primary particles. Image forming method. 2. The image forming method according to claim 1, wherein the black toner contains an azo metal compound represented by the following formula (1). Embedded image [M represents a metal element. R ₁ and R ₃ are a hydrogen atom, C ₁
To ₁₈ alkyl groups, C ₂ to ₁₈ alkenyl groups, sulfonamide groups, mesyl groups, sulfonic acid groups, carboxyester groups, hydroxy groups, C ₁ to ₁₈ alkoxy groups, acetylamino groups, benzoylamino groups or halogen atoms Wherein R ₁ and R ₃ are the same or different, and n and n ′
Represents an integer of 1 to 3, R ₂ and R ₄ represent a hydrogen atom or a nitro group, R ₂ and R ₄ are the same or different,
R ₅ and R ₆ are a hydrogen atom, a halogen atom, a nitro group, a carboxyl group, an anilide group, an alkyl group of C ₁ ~ _18, an alkenyl group, an aralkyl group, an alkoxy group, an aryl group, carboxy ester group or ## STR2 ] X represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a nitro group or a halogen atom, m represents an integer of 1 to 3, R ₅ and R ₆ are the same or different,
A ⁺ represents a hydrogen ion, a sodium ion, a potassium ion, an ammonium ion or a mixture thereof. ] 3. The image forming method according to claim 1, wherein the black toner contains a solid wax. 4. The dispersion state of the carbon black is a ≦
The image forming method according to claim 1, wherein b ≦ 3a. 5. The image forming method according to claim 1, wherein the average primary particle diameter of the carbon black is 25 to 55 mμ. 6. The image forming method according to claim 1, wherein the carbon black has a DBP oil absorption of 30 to 100 ml / 100 g. 7. The image forming method according to claim 1, wherein the carbon black has a DBP oil absorption of 30 to 70 ml / 100 g. 8. The black toner contains 20% by number or less of toner particles having a particle size of 4 μm or less.
The image forming method according to any one of claims 1 to 7, wherein toner particles having a size of 7 µm or more are contained in an amount of 1.5 vol% or less. 9. The image forming method further includes a transfer step of transferring the toner image to a transfer material with or without an intermediate transfer member after the development step. In order, (I) the charging section of the latent image carrier in the charging step, (II) the developing section of the electrostatic latent image in the developing step, and (III) the transfer section of the toner image in the transferring step are sequentially positioned. Cleaning means for contacting and removing the toner remaining on the surface of the latent image carrier after the transfer step with the surface of the latent image carrier is provided between the transfer section and the charging section and the charging section. And between the developing unit and
9. The image forming method according to claim 1, wherein the toner remaining on the surface of the latent image carrier after the transfer step is removed by the developing device in the developing step. 10. The image forming method according to claim 1, wherein the charging member has conductive fibers or conductive magnetic particles. 11. The contact charging means is a magnetic brush charger in which conductive magnetic particles are magnetically constrained.
The image forming method according to any one of the above. 12. The image forming method according to claim 10, wherein the weight average particle diameter of the conductive magnetic particles is 5 to 45 μm. 13. The image forming method according to claim 10, wherein a weight average particle size of the conductive magnetic particles is smaller than a weight average particle size of the magnetic carrier. 14. The image forming method according to claim 1, wherein the moving direction of the surface of the developer carrier is a counter direction with respect to the moving direction of the surface of the latent image carrier. 15. The latent image carrier has a cylindrical shape.
Diameter d₁The developer carrier has a cylindrical shape.
And the diameter d_TwoAnd the diameter d₁And the diameter d_TwoWith
Ratio (d ₁/ D_Two) Is 1.0 to 3.0.
15. The image forming method according to any one of 14. 16. The ratio of the diameter d ₁ to the diameter d ₂ (d ₁ /
The image forming method according to claim 1, wherein d ₂ ) is from 1.0 to 2.2. 17. The image forming method according to claim 1, wherein a developing bias having a discontinuous alternating voltage is applied to the developer carrying member during the development by the developing device. 18. The image forming method according to claim 1, wherein the toner image is a color toner image having the black toner and the chromatic color toner. 19. The toner image according to claim 1, wherein the toner image is a full-color toner image including the black toner, the cyan toner, the magenta toner, and the yellow toner.
The image forming method according to any one of the above. 20. The image forming method according to claim 1, wherein the toner particles are toner particles produced by a polymerization method. 21. A charging step of charging a latent image carrier by bringing a contact charging means into contact with a latent image carrier for carrying an electrostatic latent image; and an electrostatic latent image on the charged latent image carrier. A developing container holding a one-component developer having toner particles, and a developer for carrying the one-component developer held in the developing container and transporting the one-component developer to a development area Using a developing device having a carrier, the electrostatic latent image carried on the latent image carrier in a development area is at least one component carried on the surface of the latent image carrier by the developer carrier. An image forming method comprising a developing step of forming a developer image by contacting a developer layer of a system developer to form a developer image, wherein the surface layer of the latent image carrier has a volume resistance (A) of 10 ⁸ to 10 ⁸ .
10 is a ¹⁴ Omega · cm, the toner is, contains at least a binder resin and carbon black, the weight average particle diameter of the toner is 3 to 10 [mu] m, an average primary particle diameter of the carbon black in 13~60mμ A, and in a dispersed state in the toner, a ≦ b, where a is the number of agglomerates having less than 10 primary particles and b is the number of agglomerates having 10 or more primary particles. Image forming method. 22. The black toner according to the following formula (1):
22. The image forming method according to claim 21, comprising an azo metal compound represented by the following formula: Embedded image [M represents a metal element. R ₁ and R ₃ are a hydrogen atom, C ₁
To ₁₈ alkyl groups, C ₂ to ₁₈ alkenyl groups, sulfonamide groups, mesyl groups, sulfonic acid groups, carboxyester groups, hydroxy groups, C ₁ to ₁₈ alkoxy groups, acetylamino groups, benzoylamino groups or halogen atoms Wherein R ₁ and R ₃ are the same or different, and n and n ′
Represents an integer of 1 to 3, R ₂ and R ₄ represent a hydrogen atom or a nitro group, R ₂ and R ₄ are the same or different,
R ₅ and R ₆ are a hydrogen atom, a halogen atom, a nitro group, a carboxyl group, an anilide group, C ₁ ~ ₁₈ alkyl group, an alkenyl group, an aralkyl group, an alkoxy group, an aryl group, carboxy ester group or embedded ] X represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a nitro group or a halogen atom, m represents an integer of 1 to 3, R ₅ and R ₆ are the same or different,
A ⁺ represents a hydrogen ion, a sodium ion, a potassium ion, an ammonium ion or a mixture thereof. ] 23. The image forming method according to claim 21, wherein the black toner contains a solid wax. 24. The dispersion state of the carbon black is a
24. The image forming method according to claim 21, wherein ≤b≤3a. 25. The image forming method according to claim 21, wherein the average primary particle diameter of the carbon black is 25 to 55 mμ. 26. The carbon black having a DBP oil absorption of 30 to 100 ml / 100 g.
5. The image forming method according to any one of 5. 27. The image forming method according to claim 21, wherein the carbon black has a DBP oil absorption of 30 to 70 ml / 100 g. 28. The black toner contains 20% by number or less of toner particles having a particle size of 4 μm or less.
The image forming method according to any one of claims 21 to 27, comprising toner particles having a particle size of 0.1 µm or more and 2.0 vol% or less. 29. The image forming method, further comprising a transfer step of transferring the toner image to a transfer material with or without an intermediate transfer member after the development step. In order, (I) the charging section of the latent image carrier in the charging step, (II) the developing section of the electrostatic latent image in the developing step, and (III) the transferring section of the toner image in the transferring step are located in this order. Cleaning means for contacting and removing the toner remaining on the surface of the latent image carrier after the transfer step with the surface of the latent image carrier is provided between the transfer section and the charging section and the charging section. 29. The developing device according to claim 21, wherein the developing device also serves as a means for removing the toner remaining on the surface of the latent image carrier after the transferring step. The image forming method according to any one of the above. 30. The image forming method according to claim 21, wherein the charging member has conductive fibers or conductive magnetic particles. 31. The image forming method according to claim 21, wherein the contact charging unit is a magnetic brush charger in which conductive magnetic particles are magnetically constrained. 32. The image forming method according to claim 30, wherein the conductive magnetic particles have a weight average particle size of 5 to 45 μm. 33. The image forming method according to claim 21, wherein the moving direction of the surface of the developer carrier is a counter direction with respect to the moving direction of the surface of the latent image carrier. 34. The latent image carrier has a cylindrical shape.
Diameter d₁The developer carrier has a cylindrical shape.
And the diameter d_TwoAnd the diameter d₁And the diameter d_TwoWith
Ratio (d ₁/ D_Two) Is 1.0 to 3.0.
35. The image forming method according to any one of to 33. 35. The ratio of the diameter d ₁ to the diameter d ₂ (d ₁ /
The image forming method according to any one of claims 21 to 33 d ₂₎ is 1.0 to 2.2. 36. The image forming method according to claim 21, wherein the toner image is a color toner image including the black toner and the chromatic color toner. 37. The toner image according to claim 21, wherein the toner image is a full-color toner image including the black toner, the cyan toner, the magenta toner, and the yellow toner.
5. The image forming method according to any one of 5. 38. The image forming method according to claim 21, wherein the toner particles are toner particles produced by a polymerization method.