JPH09146304A - Toner for developing electrostatic charge image, developer and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce weakly electrified toner and excessively electrified toner, to realize uniform electrification, and to obtain stable electrification performance even in the case the particle size of toner is made small by setting the toner to have specified BET value specific surface area and a specified shape coefficient. SOLUTION: This toner for developing an electrostatic charge image has the BET value specific surface area being >=5m<2> /g and the shape coefficient being 1.01 to 1.5. The BET value specific surface area is measured by one point method of a nitrogen absorption method and the shape coefficient is defined as the peripheral length of a toner particle/the periphery equivalent to circle of a particle. The toner has shape comparatively approximate to a sphere and large surface area. Since the toner has the specified shape and the large surface area, it is uniformly electrified at an early stage. Thus, the toner capable of realizing high developing speed, having excellent durability, preventing fogging from occurring even in the case of long-term use, and being excellent in transfer performance and cleaning performance, especially, blade cleaning performance is obtained.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The present invention uses a toner for developing an electrostatic charge image having a stable charging performance, a high developing speed, an excellent durability and a small fog, a developer and the above toner. The present invention relates to an image forming method.

[0002]

2. Description of the Related Art In recent years, the electrophotographic development system has been used in various fields. For example, it is used not only in copying machines but also in the fields of printers, which are output terminals of computers, color copying machines, color printers, and the like. As this usage progresses, the demand for image quality is increasing. For this reason, various demands for the toner itself have been demanded such as improvement of charging performance.

There are various proposals for improving the image quality by reducing the particle size of the toner in order to improve the image quality, and there are no shortfalls in the list. However, in the case of a so-called conventional toner having a small particle size, the adhesion force due to the so-called Van der Waals force is increased by simply reducing the particle size of the toner itself, so that it is possible to impart desired chargeability to the toner. It becomes difficult, and the presence of weakly charged toner and overcharged toner increases, causing fog in the image after long-term use, and causing problems such as contamination of the carrier in the developing device or the two-component developing method. After all, the toner itself cannot endure long-term use, and the durability of the toner is lowered. Further, since the adhesion of the toner having a reduced particle size to the surface of the photoconductor becomes high,
There are also problems that the transfer performance from the photoconductor to the transfer material is deteriorated and the cleaning property of untransferred toner remaining on the photoconductor is deteriorated.

[0004]

In contrast to the problems described above, the object of the present invention is to reduce the generation of weakly chargeable toner even when the particle size is reduced, and the generation of toner that is overcharged. An object of the present invention is to provide an electrostatic charge image developing toner and an electrostatic charge image developer which can be charged in a small amount and can be uniformly charged and have stable charging performance.

A further object of the present invention is to provide a toner for developing an electrostatic charge image, which has a high developing speed, is excellent in durability, does not cause fog even when used for a long period of time, and is excellent in cleaning performance, and an electrostatic charge image developing. To provide the agent.

Still another object of the present invention is to provide an image forming method in which the above electrostatic image developing toner can be preferably used.

[0007]

The above object of the present invention is achieved by the following means.

[1] A toner for developing an electrostatic charge image, which has a BET value specific surface area of 5 m ² / g or more and a shape factor of 1.01 to 1.5.

[2] BET value Specific surface area of 5 m ² / g or more, and weight average molecular weight (Mw) / number average molecular weight (M
A toner for developing an electrostatic charge image, which comprises a resin having a ratio of n) of less than 5.

[3] A developer containing a toner for developing an electrostatic image having a BET value specific surface area of 5 m ² / g or more and a shape factor of 1.01 to 1.5.

[4] BET value Specific surface area is 5 m ² / g or more, and weight average molecular weight (Mw) / number average molecular weight (M
A developer comprising an electrostatic charge image developing toner containing a resin having a ratio of n) of less than 5.

[5] In an image forming method for developing an electrostatic latent image on a photoconductor with a toner image, the toner has a BET value specific surface area of 5 m ² / g or more and a shape factor of 1.01 to 1.01.
An image forming method, wherein the toner is an electrostatic image developing toner having a value of 1.5.

[6] In an image forming method for developing an electrostatic latent image on a photoreceptor with a toner image, the toner has a BET value specific surface area of 5 m ² / g or more and a weight average molecular weight (M
An image forming method, which is a toner for developing an electrostatic charge image containing a resin having a ratio of w) / number average molecular weight (Mn) of less than 5.

[7] In an image forming method of transferring a toner image formed on an image support onto a transfer material, the toner has a BET value specific surface area of 5 m ² / g or more and a shape factor of 1. An image forming method comprising: an electrostatic charge image developing toner containing a resin of 01 to 1.5.

[8] In an image forming method of transferring a toner image formed on an image support onto a transfer material, the toner has a BET value specific surface area of 5 m ² / g or more and a weight average molecular weight (Mw). ) / Number average molecular weight (Mn) ratio is a toner containing a resin of less than 5, an image forming method characterized by the above.

[0016]

[9] In an image forming method in which a toner image formed on an image support is transferred onto a transfer material and then the toner remaining on the support is cleaned, the toner has a BET value specific surface area of 5 m ^2. / G or more, and a toner having a shape factor of 1.01 to 1.5, an image forming method.

[10] In the image forming method, in which the toner image formed on the image support is transferred onto a transfer material, and then the toner remaining on the support is cleaned, in which the toner has a BET value specific surface area. Is 5 m ² / g or more and the weight average molecular weight (Mw) / number average molecular weight (Mn) ratio is less than 5, a toner containing a resin.

The BET value specific surface area 5 according to the present invention will be described below.
The toner for developing an electrostatic charge image having a shape factor of m ¹ / g or more and 1.01 to 1.5 (hereinafter, referred to as toner of the present invention) will be described in detail.

One of the characteristics of the toner of the present invention is that the BET value specific surface area is 5 m ² / g or more, and this BET value specific surface area is measured by the one-point method of nitrogen adsorption method, specifically Shimadzu. It is measured with a Flowsorb 2300 measuring device manufactured by Seisakusho.

One of the characteristics of the toner of the present invention is that the shape factor is 1.01 to 1.5. This shape factor is defined by the perimeter of toner particles / the circumference of a circle of particles,
Specifically, it is defined by the following formula.

[0021]

(Equation 1)

In the above equation, L is the perimeter of the toner particles (μ
m) and A represent the projected area (μm ² ) of the toner particles.

For L and A in the above formula, toner particles were projected, and L and A at the time of projection were measured. Specifically, an electron microscope photograph was taken at a magnification of 1000 times, and using the photograph, n = 100 to 1000 for each of L and A.
The average value of is measured by an image analyzer (SPICCA: manufactured by Nippon Avionics Co., Ltd.).

The toner of the present invention is a toner having the above-mentioned characteristics, and is a toner having a relatively spherical shape and a large surface area, and has a specific shape and a large surface area. It is presumed that various purposes can be achieved. That is, since it has a large surface area while having a shape that is relatively close to a sphere, it can be uniformly charged in an early stage, so that the developing speed is fast, the durability is excellent, and the fog does not occur even when used for a long period of time. It is presumed that it is possible to obtain a toner that does not generate, has excellent transfer performance, and has excellent cleaning performance, particularly blade cleaning performance described below.

(1) Composition and production method of toner of the present invention The toner of the present invention is characterized by having a BET value specific surface area of 5 m ² / g or more, but from a technical viewpoint, it is 150 m ^2. / G or less, but preferably 100 m ²
/ G or less, and particularly preferably 5 to 50 m ² / g. More preferably 5 to 40 m ² / g, and especially preferably from 10 to 40 m ² / g.

The toner of the present invention has a shape factor of 1.01.
However, the shape factor is preferably 1.05 to 1.3.

That is, those having an excessively large BET value specific surface area have very fine irregularities and are difficult to manufacture. Further, even if a surface having such a surface is obtained, it becomes finer than the unevenness that contributes to charging, and the effect is saturated.

The toner of the present invention has the above-mentioned characteristics, but it is preferable that the toner contains at least a resin and a colorant, and if necessary, contains a releasing agent which is a fixing property improving agent, a charge control agent and the like. You can also do it. Further, an external additive composed of inorganic fine particles, organic fine particles or the like may be added to colored particles composed of a so-called resin and a colorant.

The toner of the present invention may be made into powder having a desired shape factor by pulverizing elementary particles obtained by melting and kneading a resin, a colorant, etc. It is also possible to carry out emulsion polymerization by mixing additives, to produce fine polymer particles, and then to produce by associating by adding an organic solvent, a flocculant, etc., in the present invention, this method is It is preferably used.

The method for producing the toner of the present invention is not particularly limited as described above, but it is preferably JP-A-5-265252, Japanese Patent Application No. 5-1155572, Japanese Patent Application No. 6-223953. The method described in 1. is used. That is, a method of associating a plurality of fine particles composed of a resin, a colorant and the like, particularly a method of treating them in water with an aggregating agent having a concentration equal to or higher than the critical aggregation concentration and an organic solvent infinitely soluble in water is preferable. It is used. further,
The toner having the BET value specific surface area and shape factor of the present invention can be formed by heating and fusing at a temperature not lower than the glass transition temperature of the formed polymer itself.

Specifically, those preferably used as the monomer constituting the resin are styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene and p-.
Chlorostyrene, 3,4-dichlorostyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, pt-butylstyrene, pn-hexylstyrene, pn-octylstyrene, p- Styrenes such as n-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene or styrene derivatives, aromatic vinyl compounds such as vinylnaphthalene; methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, methacryl Isopropyl acetate, isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate. Methacrylic acid ester derivatives and the like, methyl acrylate, ethyl acrylate, isopropyl acrylate, n- butyl acrylate, t-
Α-methylene aliphatic monocarboxylic acid esters such as butyl ester, isobutyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, phenyl acrylate, and the like; ethylene, Olefins such as propylene and isobutylene; halogen-based vinyls such as vinyl chloride, vinylidene chloride, vinyl bromide, vinyl fluoride, vinylidene fluoride; vinyl esters such as vinyl propionate, vinyl acetate, vinyl benzoate; vinyl methyl Vinyl ethers such as ether and vinyl ethyl ether; vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone and vinyl hexyl ketone; N-vinyl compounds such as N-vinyl carbazole, N-vinyl indole and N-vinyl pyrrolidone , Acrylonitrile, methacrylonitrile, there are acrylic acid or methacrylic acid derivatives such as acrylamide. Among these monomers, aromatic vinyl compounds and α-methylene aliphatic monocarboxylic acid esters are preferable.

These vinyl-based monomers can be used alone or in combination to obtain a copolymer, which can be used in a toner. Further, it is more preferable to use a combination of monomers having an ionic dissociation group as monomers constituting the resin. For example, those having a substituent such as a carboxy group, a sulfo group, and a phospho group as a constituent group of a monomer, specifically, acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumaric acid, Maleic acid monoalkyl ester, itaconic acid monoalkyl ester, styrenesulfonic acid, allylsulfosuccinic acid, 2-acrylamido-2-methylpropanesulfonic acid, acid phosphooxyethyl methacrylate, 3-chloro-2-
Acid phosphooxypropyl methacrylate and the like can be mentioned.

These ionic dissociative groups are polyvalent metals,
For example, it is preferable that the copolymer is substituted with zinc or magnesium and that the copolymer has a so-called metal crosslinked structure.

Further, as monomers, divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neo It is also possible to use a polyfunctional vinyl such as pentyl glycol diacrylate to form a resin having a crosslinked structure.

These monomers can be polymerized with a radical polymerization initiator to give a resin. In this case, an oil-soluble polymerization initiator can be used in the suspension polymerization method or the solution polymerization method. As this oil-soluble polymerization initiator, azoisobutyronitrile, lauryl peroxide, benzoyl peroxide and the like can be used. When an emulsion polymerization method is used, a water-soluble radical polymerization initiator can be used. Examples of the water-soluble polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate, azobisaminodipropane acetate, azobiscyanovaleric acid and salts thereof, and hydrogen peroxide.

In the present invention, an excellent resin having a glass transition point of 20 to 90 ° C. is preferable and a softening point of 8
It is preferably 0 to 220 ° C. The glass transition point is measured by a differential calorimetric analysis method, and the softening point can be measured by a drop-type flow tester. Further, for these resins, the molecular weight measured by gel permeation chromatography (GPC) is the number average molecular weight (M
It is preferable that the n) is 1,000 to 500,000, or the weight average molecular weight (Mw) is 2,000 to 1,000,000. Further, as the molecular weight distribution, Mw / Mn is less than 5.0, preferably 3.0 or less, and the lower limit value is 1.0 or more.

The molecular weight is measured by GPC at a temperature of 40 ° C.
In, the measurement is carried out by flowing tetrahydrofuran at a flow rate of 1.0 ml / min and injecting 100 μl of a tetrahydrofuran sample solution having a concentration of 0.01 g / 20 ml. In measuring the molecular weight of a sample, the measurement conditions included in the range where the logarithm of the molecular weight and the count number of the calibration curve produced by monodisperse polystyrene of several kinds having the sample have a linear range are selected. The peak molecular weight is calculated from the obtained GPC chromatogram count number using the calibration curve.

In the present invention, since the resin obtained as described above is obtained in the form of fine particles, particularly when it is obtained by the emulsion polymerization method, a coagulant is used and a solvent infinitely soluble in water is further added. Then, by heat-treating at a temperature not lower than the glass transition point of the obtained resin, particles (toner) having a desired particle diameter can be obtained.

When producing the toner of the present invention, the aggregating agent used is not particularly limited,
Those selected from metal salts are preferably used. Specifically, as the monovalent metal, for example, sodium, potassium,
Alkali metal salts such as lithium, divalent metals such as alkaline earth metal salts such as calcium and magnesium, divalent metal salts such as manganese and copper, and trivalent metal salts such as iron and aluminum. And specific salts include sodium chloride, potassium chloride, lithium chloride, calcium chloride, zinc chloride, copper sulfate, magnesium sulfate,
Examples thereof include manganese sulfate and the like. These may be used in combination.

These coagulants are used by adding them at a critical coagulation concentration or more. The critical aggregation concentration is an index relating to the stability of the aqueous dispersion, and indicates the concentration at which aggregation occurs when a coagulant is added. This critical coagulation concentration greatly changes depending on the emulsified component and the dispersant itself. For example, Seizo Okamura et al., “Polymer Chemistry Vol.
17, p601 (1960) edited by The Society of Polymer Science, Japan, etc., and a detailed critical aggregation concentration can be obtained. Further, as another method, a desired salt is added to the target particle dispersion at a different concentration, and the resulting dispersion is subjected to ζ (zeta).
The potential can be measured, and the salt concentration at which this value changes can be determined as the critical aggregation concentration.

The amount of the flocculant used in the present invention may be at least the critical flocculation concentration, but is preferably 1.2 times or more the critical flocculation concentration, more preferably 1.5 times or more. .

The solvent infinitely soluble in water to be used is a colored polymer dispersion liquid, that is, a solvent infinitely soluble in an aqueous dispersion liquid, and this solvent is a resin formed in the present invention. Those that do not dissolve are selected. Specific examples include alcohols such as methanol, ethanol, propanol, isopropanol, t-butanol, methoxyethanol and butoxyethanol, nitriles such as acetonitrile, and ethers such as dioxane. Particularly, ethanol, propanol and isopropanol are preferable.

The amount of the solvent that dissolves infinitely is 1 to 300% by volume with respect to the polymer-containing dispersion liquid to which the flocculant is added.
Is preferred.

As the polymerization method for forming the resin used in the toner of the present invention, various methods can be used.
The above-mentioned emulsion polymerization method is particularly preferable.

Various colorants and property improvers such as fixability improvers can be used in the toner of the present invention. Carbon black, magnetic materials, dyes, pigments and the like can be arbitrarily used as the colorant that can be used, and channel black, furnace black, acetylene black, thermal black / lamp black and the like can be used as carbon black. As the magnetic material, ferromagnetic metals such as iron, nickel and cobalt, alloys containing these metals, compounds of ferromagnetic metals such as ferrite and magnetite, alloys which do not contain ferromagnetic metals but show ferromagnetism by heat treatment, For example, an alloy of a type called a Heusler alloy such as manganese-copper-aluminum, manganese-copper-tin, chromium dioxide, or the like can be used. As the dye, C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 1
22, C.I. I. Solvent Yellow 19, 44, 7
7, 79, 81, 82, 93, 98, 10
3, 104, 112, 162, C.I. I. Solvent Blue 25, 36, 60, 70, 93, 9
5 and the like, and mixtures thereof can also be used. Examples of the pigment include C.I. I. Pigment Red 5,
48: 1, 53: 1, 57: 1, 122, 1
39, 144, 149, 166, 177, 1
78, 222, C.I. I. Pigment Orange 31, 43 and C.I. I. Pigment Yellow 14, Same 17 and Same 9
3, 94, 138, C.I. I. Pigment Green 7, C.I. I. Pigment Blue 15: 3, 60 and the like, and mixtures thereof can also be used. These colorants have a number average primary particle diameter of about 10 to 200.
It is preferable to use particles having a size of about nm dispersed in the toner.

As a method for adding the colorant, when the toner of the present invention is prepared by an emulsion polymerization method, the polymer itself is prepared by an emulsion polymerization method and then added at the stage of aggregating by adding an aggregating agent. A method or a method of adding a colorant at the stage of polymerizing the monomer can be used. In addition,
When the colorant is added at the stage of preparing the polymer, it is preferable to treat the surface with a coupling agent or the like before use so as not to hinder the radical polymerizability.

Further, low molecular weight polypropylene (number average molecular weight = 1,500 to 9000) as a fixing property improving agent.
0) or low molecular weight polyethylene may be added. Further, an azo-based metal complex, a quaternary ammonium salt, or the like may be used as a charge control agent. These property modifiers are usually added to the toner in the same manner as the colorants.

From the viewpoint of imparting fluidity, it may be added to colored particles obtained by polymerizing inorganic fine particles and organic fine particles. In this case, it is preferable to use inorganic fine particles, and it is preferable to use inorganic oxide particles such as silica, titania, and alumina, and further, these inorganic fine particles are subjected to a hydrophobic treatment with a silane coupling agent, a titanium coupling agent, or the like. Is preferred.

The toner of the present invention can be produced by associating a plurality of the above-mentioned polymers themselves with each other. In this case, a metal as an aggregating agent is added to the dispersion liquid of the polymer particles under stirring. It can be obtained by adding a salt in an amount not less than the critical coagulation concentration, further adding the above-mentioned solvent infinitely soluble in water, and further heat-treating at a temperature not lower than the glass transition temperature of the polymer.

The particle size of the toner of the present invention itself is arbitrary, but those having a small particle size are more likely to exhibit the effects of the present invention and exhibit a large improvement effect, and the volume average particle size is 2 to 10 μm.
Those having 3 to 9 μm are particularly preferable.
This particle size can be controlled by the concentration of the flocculant, the amount of the organic solvent added, and the composition of the polymer itself.

The toner of the present invention is used as a one-component magnetic toner containing a magnetic material, used as a two-component developer mixed with a so-called carrier, and used as a non-magnetic toner alone. However, any of them can be preferably used, but in the present invention, it is preferably used as a two-component developer mixed with a carrier.

As the carrier constituting the two-component developer, either an uncoated carrier composed only of magnetic material particles such as iron or ferrite, or a resin coated carrier in which the surface of the magnetic material particles is coated with a resin is used. Good. The average particle size of this carrier is 30 to 1 in terms of volume average particle size.
50 μm is preferred. The resin for coating is not particularly limited, but examples thereof include styrene-acrylic acid ester resin and silicon resin.

(2) Structure of Image Forming Method The developing system in which the toner of the present invention can be used is not particularly limited, and it can be suitably used in a contact developing system or a non-contact developing system. In the contact-type development, the layer thickness of the developer having the toner of the present invention is 0.1 to 8 mm, preferably 0.4 to 5 mm in the development area, and the developer is erected in the development area. It is developed by the magnetic brush development method. Further, in this case, the gap between the photoconductor and the developer carrying member is 0.15 to 7 mm, particularly 0.2 to 4 mm.
mm.

In the non-contact type developing system, the developer layer formed on the developer carrying member and the photoconductor are not in contact with each other. The developer layer is a thin layer in order to constitute this developing system. Is preferably formed. In this method, a developer layer having a thickness of 20 to 500 μm is formed in a development region on the surface of the developer carrier, and a gap between the photoconductor and the developer carrier has a larger gap than the developer layer.

In particular, the toner of the present invention has a high charge rising property and is useful for a non-contact developing method. That is, in the non-contact developing method, since the change in the developing electric field is large, a minute change in the charging greatly affects the developing itself.
For this reason, the image quality,
This causes large fluctuations in developability such as density. However, since the toner of the present invention has a high charge rising property, the change in charge is small, and a stable charge amount can be secured. Therefore, a stable image can be formed for a long time even by the non-contact developing method. it can.

In the non-contact developing method, the thin layer is formed by a method of pressing a developer layer regulating rod against the surface of a developer carrying member or a magnetic blade using magnetic force. Further, there is also a method of contacting a surface of a developer bearing member with a urethane blade, a phosphor bronze plate or the like to regulate the developer layer. The pressing force of the pressing regulating member is preferably from 1 to 15 gf / mm. When the pressing force is small, the conveyance is likely to be unstable because the regulating force is insufficient. On the other hand, when the pressing force is large, the stress on the developer is increased, and the durability of the developer is likely to be reduced. A preferred range is 3 to 10 gf / mm. Further, in the non-contact developing method, it is preferable to apply a developing bias voltage at the time of development, but in this case, a method of applying only a DC component or a method of applying an AC bias in a superimposed manner may be used.

The size of the developer carrying member is 10 in diameter.
It is preferable that the magnet is held within a range of -40 mm.
If the diameter is too small, the mixing of the developer will be insufficient, and it will be difficult to ensure sufficient mixing to give sufficient charge to the toner.If the diameter is too large, the centrifugal force against the developer will be insufficient. It becomes large and the problem of toner scattering tends to occur.

An example of the non-contact developing method will be described below with reference to FIG.

FIG. 1 is a schematic view of a non-contact developing type developing section which can be preferably used in the image forming method of the present invention. 1 is a photoconductor, 2 is a developer carrier, and 3 is the toner of the present invention. The contained two-component developer, 4 is a developer layer regulating member, 5 is a developing region, 6 is a developer layer, and 7 is a power source for forming an alternating electric field.

The two-component developer containing the toner of the present invention is carried by the magnetic force on the developer carrier 2 having the magnet 2B therein, and is transported to the developing area 5 by the movement of the developing sleeve 2A. At the time of this conveyance, the developer layer 6 is regulated by the developer layer regulating member 4 in the developing region 5 to a layer of that thickness so as not to come into contact with the photoreceptor 1.

The minimum gap (Dsd) of the developing area 5 is the thickness of the developer layer 6 conveyed to that area (preferably 20 to 5).
00 μm), for example, about 100 to 1000 μm. The power source 7 for forming the alternating electric field is preferably an alternating current having a frequency of 1 to 10 kHz and a voltage of 1 to 3 kVp-p. The power supply 7 may have a configuration in which direct current is added in series to alternating current as necessary. 300 when adding DC voltage
~ 800V is preferred.

When the toner of the present invention is applied to a color image forming system, a system in which a monochrome image is formed on a photoconductor and successively transferred to an image support (this system is referred to as a sequential transfer system and is shown in FIG. 2). Alternatively, a method of developing a single color image on a photoconductor a plurality of times to form a color image and then collectively transferring the image to an image support (this is referred to as a batch transfer method and is shown in FIG. 3).
And the like.

The image forming method shown in FIGS. 2 and 3 will be described in detail below.

As the developer carrying member used in the present invention, as shown in FIGS. 1, 2 and 3, a developing device in which a magnet 2B is incorporated inside the carrying member is used to form the surface of the developer carrying member. As the sleeve 2A to be used, aluminum, stainless steel whose surface is oxidized, or stainless steel is used.

An example of the sequential transfer method shown in FIG. 2 will be described below.

Reference numeral 11 is a charging device which is a charging electrode, and 12 is a developing unit which is a developing device for loading yellow, magenta, cyan and black toners, respectively, and is divided into four units corresponding to four color toners. . The basic configuration of these developing units is the same as the schematic diagram of the developing unit shown in FIG. 14 is a photoconductor drum, 13 is a cleaning unit, 15 is a holding unit for temporarily holding a monochromatic color toner image formed on the photoconductor drum, and further is for holding the next monochromatic toner image thereon.
A transfer drum that finally forms the desired multicolor image.
Reference numeral 16 is a transport unit for transporting a transfer material on which a toner image on the transfer drum is transferred. Reference numeral 17 is an inside of the transfer drum 15 and is an attraction electrode for corona-discharging from the inside to electrostatically attract the transfer material to the drum. , 18 are transfer poles for sequentially transferring the toner images formed on the photoconductor 14 to a transfer drum, 19
Is a peeling electrode for peeling off the transfer material electrostatically adsorbed on the transfer drum 15, and 20 is a removing electrode for removing the electric charge remaining on the transfer drum after the transfer material is peeled off.

By the strip electrode 11 on the photosensitive drum 14,
A uniform charge is formed, followed by imagewise exposure (means not shown) to form an electrostatic latent image. This electrostatic latent image is developed by a developing device that holds one color toner (for example, black toner) of the developing unit 12, and a one color toner image is formed on the photosensitive drum 14. On the other hand, the transfer material transported by the transport unit 16 onto the transfer drum 15 is attracted to the adsorption electrode 17.
Is electrostatically adsorbed on the transfer drum and is conveyed to the transfer section.

At the transfer portion, the toner image formed on the photosensitive drum 14 is transferred to the conveyed transfer material. The toner remains on the photosensitive drum 14 after the transfer of the transfer image, and the remaining toner is cleaned by the cleaning unit 13 and used for the next process. When forming a multicolor image, toner images of other colors are formed by development according to a similar process and transferred one by one to the transfer drum 15. Eventually, a desired toner image is formed on the transfer material adsorbed on the transfer drum 15. The transfer material on which a desired toner image is formed is peeled off by the peeling electrode 19 and conveyed to the fixing section, where a final fixed multicolor toner image is obtained. On the other hand, the transfer drum 15 has the remaining charge removed by the depolarizer 20 and is used in the next process.

Next, the batch transfer method will be described with reference to FIG.

Since each part of the apparatus is the same as the example of FIG. Here, reference numeral 21 denotes a transport unit that transfers the toner image while transporting the transported transfer material. Photoconductor drum 1
Electric charges are uniformly formed on the surface 4 by a charging electrode, and then an electrostatic latent image is formed by a latent image forming means (means not shown).
This electrostatic latent image is developed by a developing device having a toner (for example, black toner) of one color of the developing unit 12, and a toner image of one color is formed on the photosensitive drum. In the illustrated example, this toner image is not transferred, and the charge electrode 11 uniformly forms an electric charge again on the photosensitive drum having the toner image as it is, and further an electrostatic latent image is formed. Then, it is developed by a developing device having a toner of a color different from the above, and a toner image of another color is formed by being superposed on the previous toner image. During this time, cleaning unit 1
3, the transfer electrode 18, and the transport unit 21 do not operate, and are retracted from the photoconductor drum 14 so as not to disturb the toner image on the photoconductor drum 14.

After the desired image formation is completed and a multicolor toner image is formed, the toner image on the photosensitive drum is transferred onto the transfer material carried by the carrying unit 16 while being carried by the carrying section 21. The toner image is transferred by the electrode 18. The transfer material carrying the transferred toner image is transported to a fixing unit, where it is fixed, and a final multicolor toner image is formed on the transfer material. After the toner image is transferred, the toner remains on the photosensitive drum 14, so that the cleaning unit 13 cleans the toner and the toner is used in the next process.

The toner image formed on the photoreceptor by the above-mentioned various methods is transferred to a transfer material such as paper in the transfer process. The transfer method is not particularly limited, and various methods such as a so-called corona transfer method and a roller transfer method can be adopted.

Since the toner of the present invention has a high transfer efficiency and a small amount of toner remains on the photosensitive member, when the blade cleaning system is used, for example, the pressing force of the blade to the photosensitive member can be reduced, and It also has an effect that it can contribute to a longer life.

After the toner image is transferred to the transfer material, the toner remaining on the photoconductor is removed by cleaning, and the photoconductor is repeatedly used in the next process.

The mechanism for cleaning in the present invention is not particularly limited, and a known cleaning mechanism such as a blade cleaning system, a magnetic brush cleaning system, a fur brush cleaning system, etc. can be arbitrarily used. A preferable cleaning mechanism is a blade cleaning method using a so-called cleaning blade for the above-described reason.

As this structure, any of the structures shown in FIGS. 4 and 5 can be used. In FIGS. 4 and 5, the cleaning blade 31 is held by the holder 33, 1 is the photoconductor, θ is the angle formed by the holder 33 and the photoconductor 1, and in FIGS.
It is 0 °, preferably 15 to 75 °. As a material forming the cleaning blade 31, an elastic body such as silicon rubber or urethane rubber can be used. In this case, it is preferable that the rubber hardness is 30 to 90 °. The thickness of the cleaning blade 31 is preferably 1.5 to 5 mm, the length outside the holder is preferably 5 to 20 mm, and the pressure contact force with respect to the photosensitive member is preferably 5 to 50 gf / mm.

[0077]

EXAMPLES The effects of the present invention will be specifically described below with reference to examples.

Colored Particle Production Example 1 Carbon black (Regal 330R: manufactured by Cabot) was used as an aluminum coupling agent (Plenact Al).
-M: Ajinomoto Co.) was added to a solution obtained by dissolving 10.67 g of sodium dodecyl sulfate in 4.92 g of pure water in 120 ml of pure water, and applying ultrasonic waves with stirring to disperse an aqueous dispersion of carbon black. Was prepared. Also,
A low molecular weight polypropylene (number average molecular weight = 3200) was emulsified in water with a surfactant while heating to prepare an emulsion dispersion having a solid content concentration of 20% by weight. 43 g of a low-molecular-weight polypropylene emulsion dispersion was mixed with the above carbon black dispersion, and styrene monomer 98.
After adding 1 g, n-butyl acrylate monomer 18.4 g, methacrylic acid monomer 6.1 g, t-dodecyl mercaptan 3.3 g, and deaerated pure water 850 ml,
The temperature was raised to 70 ° C. while stirring under a nitrogen stream. Then, 200 ml of pure water in which 4.1 g of potassium persulfate was dissolved.
Was added and reacted at 70 ° C. for 6 hours. The resultant carbon black-containing colored particle dispersion is referred to as “dispersion 1”.
The primary particle size (light scattering electrophoretic particle size analyzer ELS-800: manufactured by Otsuka Electronics Co., Ltd.) and molecular weight distribution (using GPC; styrene-equivalent molecular weight) of this product were measured.
The results are shown in Table 1 below.

To 600 ml of this "dispersion liquid 1", 2.
160 ml of a 7 mol / liter potassium chloride aqueous solution was added, and further, 40 ml of pure water in which 94 ml of isopropyl alcohol and 5.4 g of polyoxyethylene octylphenyl ether (average degree of polymerization of ethylene oxide was 10) were dissolved were added. Then, the temperature was raised to 85 ° C,
The reaction was performed for 6 hours. After the completion of the reaction, the reaction solution was filtered,
After washing with water and drying, the colored particles of the present invention were obtained. This is referred to as “colored particles 1”.

Colored Particle Production Example 2 In the colored particle production example 1, C.I. I. Pigment Blue
The colored particles of the present invention were obtained in the same manner except that 15: 3 was used. The dispersion obtained here is referred to as “dispersion 2”,
The colored particles are referred to as “colored particles 2”.

Colored Particle Production Example 3 In the colored particle production example 1, C.I. I. Pigment Red 1
Colored particles of the present invention were obtained in the same manner except that No. 22 was used.
The dispersion obtained here is referred to as “dispersion 3”, and the colored particles are referred to as “colored particles 3”.

Colored Particle Production Example 4 In Colored Particle Production Example 1, C.I. I. Pigment Yellow
Except using w17, the colored particles of the present invention were obtained in the same manner. The dispersion obtained here is referred to as “dispersion 4”,
The colored particles are referred to as “colored particles 4”.

Colored Particle Production Example 5 Colored particles of the present invention were obtained in the same manner as in Colored Particle Production Example 1 except that “Dispersion 1” was used and the amount of isopropyl alcohol added was 150 ml. This is referred to as “colored particles 5”.

Colored Particle Production Example 6 Colored particles of the present invention were prepared in the same manner as in Colored Particle Production Example 2 except that "Dispersion 2" was used and the amount of the 2.7 mol / liter potassium chloride aqueous solution to be added was 250 ml. The particles were obtained. This is referred to as “colored particles 6”.

Colored Particle Production Example 7 In Colored Particle Production Example 3, except that “dispersion liquid 3” was used and the amount of isopropyl alcohol added was 68 ml, the amount of a 2.7 mol / liter potassium chloride aqueous solution was 200 ml. Similarly, colored particles of the present invention were obtained. This is referred to as “colored particles 7”.

Colored Particle Production Example 8 In Colored Particle Production Example 4, except that the amount of isopropyl alcohol to be added was 72 ml and the amount of a 2.7 mol / liter potassium chloride aqueous solution was 200 ml, except that “dispersion liquid 4” was used. Similarly, colored particles of the present invention were obtained. This is referred to as “colored particles 8”.

[0087]

[Table 1]

Comparative Colored Particle Production Example 1 Styrene-n-butyl acrylate copolymer (copolymer ratio = 85: 15, weight average molecular weight = 63000) 100
Parts, 10 parts of carbon black and 5 parts of low molecular weight polypropylene (number average molecular weight = 3200) were added and kneaded.
After pulverization and classification, comparative colored particles were obtained. This is designated as “colored particles for comparison 1”.

Comparative colored particle production example 2 In Comparative colored particle production example 1, C.V. I. Pigment Blue 15: 3
Comparative colored particles were obtained in the same manner except that was used. This is referred to as “comparative colored particles 2”.

Comparative Colored Particle Production Example 3 In Comparative Colored Particle Production Example 1, C.I. I. Pigment Red 122 was used, and comparative colored particles were obtained in the same manner. This is designated as “comparative colored particles 3”.

Comparative Colored Particle Production Example 4 In Comparative Colored Particle Production Example 1, C.I. I. Pigment Yellow 17
Comparative colored particles were obtained in the same manner except that was used. This is referred to as “comparative colored particles 4”.

Toner Production Example Hydrophobic silica (average particle size of primary number = 12 nm) was added to the above "colored particles 1" to "colored particles 8" and "comparative colored particles 1" to "comparative colored particles 4". 1% by weight was added to obtain a toner. These are "toner 1" to "toner 8" and "comparative toner 1" to "comparative toner 4".

Evaluation “Dispersion 1” to “Dispersion 4”, “Colored particles 1” to
Various physical properties of "colored particles 8", "comparative colored particles 1" to "comparative colored particles 4", "toner 1" to "toner 8" and "comparative toner 1" to "comparative toner 4" are described below. It shows in Tables 2 and 3.

Further, the molecular weight distributions of the colored particles 1 to 8 and the comparative colored particles 1 to 4 were measured under the conditions shown below to obtain the peak molecular weight, and the weight average molecular weight (M
w), number average molecular weight (Mn) and Mw / Mn were calculated.

Apparatus: Tosoh HLC-8020 Column: GMHXL 2 pieces, G2000HXL 1 piece Detector: RI Eluent flow rate: 1.0 ml / min Sample concentration: 0.01 g / 20 ml Sample amount: Sample 100 μl Calibration curve: Standard Made with polystyrene The shape factor is based on the scanning electron microscope (JSM-6400F).
A photograph magnified 1000 times using a mold: manufactured by JEOL Ltd. was measured, and the average value of L and A of 500 colored particles calculated by SPICCA (produced by Nippon Avionics Co., Ltd.) from the photograph is shown.

[0096]

[Table 2]

[0097]

[Table 3]

The evaluation was carried out by coating the above toner with a styrene-acrylic acid ester resin to give a volume average particle size of 50 μm.
Toner concentration of 7 wt%
The developer was prepared and used. In addition, the above "toner 1"
~ "Toner 8" and "Comparative Toner 1" to "Comparative Toner 4" correspond to "Developer 1" to "Developer 8"
And "Comparative developer 1" to "Comparative developer 4".

( Evaluation in Contact Development System ) Copier U-
The evaluation was performed using BIX3135 (manufactured by Konica Corp.). The developer layer thickness is 1.5 mm, and the gap (Dsd) between the photoconductor and the developer carrying member is 0.5 mm.

The cleaning device has the structure shown in FIG. 5, the angle θ formed by the holder 33 and the photosensitive member 32 is 22 °, and urethane rubber is used as the material for the cleaning blade 31. The rubber hardness was 65 °, the thickness was 2 mm, and the length outside the holder was 8 mm. Further, the pressure contact force with respect to the photoconductor is 15 gf / mm.

Evaluation was carried out in a low temperature and low humidity (10 ° C./10% RH) environment after continuous printing of 10,000 sheets, then left for 24 hours and printing was repeated until 60,000 sheets were printed. The fog density was measured. The results are shown in Table 4 below.

The fog density is a relative density with the density of the paper being 0, and is measured by a Macbeth densitometer (RD-918). For evaluation, "Developer 1", "Developer 4", "Developer 5" and "Comparative Developer 1" were used.

[0103]

[Table 4]

From the results shown in Table 4, it can be seen that the developers of the present invention show stable print states with little fog in many prints.

( Evaluation in non-contact developing system ) The non-contact transfer developing system adopts the developing system described in FIG. 3, and a color copying machine U-Bix9028 (Konica Corporation) is used.
3), and the sequential transfer method was modified by modifying the copying machine as shown in FIG. 2 and image processing was performed under the following conditions.

The photosensitive member was a negatively chargeable layered photosensitive member, and the exposure light source was a reverse development using a semiconductor laser.

Photoconductor surface potential = −550V DC bias = −250V AC bias = Vp-p: −50 to −450V Alternating electric field frequency = 1800 Hz Dsd = 300 μm Pressing restriction force = 10 gf / mm Pressing restriction rod = SUS416 (magnetic stainless steel) Made) / diameter 3 mm developer layer thickness = 150 μm developing sleeve = 20 mm Note that the developers are “developer 1” to “developer 4”, “developer 5” to “developer 8” and “comparative developer 1”. ~ "Comparative Developer 4" were used in combination as a color developer. As an evaluation method, a full-color image having a pixel ratio of 75% was used, and printing was performed in a high temperature and high humidity environment (33 ° C./80% RH). Printing is performed continuously for 1000 sheets, then 24
Printing was continued up to 10,000 sheets by leaving it for a while, and the number of sheets with uneven transfer was recorded.

The evaluation results are shown in Tables 5 and 6 below.

[0109]

[Table 5]

[0110]

[Table 6]

From the results shown in Tables 5 and 6, it can be seen that when the developer according to the present invention is used, transfer unevenness does not occur in both the sequential transfer method and the batch transfer method, which is an excellent result.

[0112]

EFFECTS OF THE INVENTION According to the present invention, even when the particle size is reduced, the amount of weakly chargeable toner is small, the amount of overcharged toner is small, stable charging performance is obtained, and the developing speed is high. Provides a toner for developing electrostatic images, which has excellent durability and does not cause fog even when used for a long period of time.
Further, by using these toners, an excellent image forming method could be provided.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of a non-contact developing system.

FIG. 2 is a schematic diagram showing an example of a sequential transfer system.

FIG. 3 is a schematic view showing an example of a batch transfer method.

FIG. 4 is a schematic view showing an example of a blade cleaning method.

FIG. 5 is a schematic view showing an example of a blade cleaning method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Developer carrier 2A Development sleeve 2B Magnet 3 Two-component developer (contains toner of the present invention) 4 Developer layer regulating member 5 Development area 6 Developer layer 7 Power supply 11 for forming alternating electric field 11 Charger (Band electrode) 12 Developing device (Developing unit) 13 Cleaning unit 14 Photoreceptor drum 15 Transfer drum 16 Conveying unit 17 Adsorption electrode 18 Transfer electrode 19 Peeling electrode 20 Eliminating electrode 21 Conveying section 31 Cleaning blade 33 Holder

 ──────────────────────────────────────────────────続 き Continued on front page (72) Inventor Hiroshi Yamazaki 2970 Ishikawacho, Hachioji-shi, Tokyo Konica Corporation

Claims (10)

[Claims] 1. A toner for developing an electrostatic charge image, which has a BET value specific surface area of 5 m ² / g or more and a shape factor of 1.01 to 1.5. 2. An electrostatic image development comprising a resin having a BET value specific surface area of 5 m ² / g or more and a weight average molecular weight (Mw) / number average molecular weight (Mn) ratio of less than 5. For toner. 3. A developer containing a toner for developing an electrostatic charge image having a BET value specific surface area of 5 m ² / g or more and a shape factor of 1.01 to 1.5. 4. A toner for developing an electrostatic charge image containing a resin having a BET specific surface area of 5 m ² / g or more and a weight average molecular weight (Mw) / number average molecular weight (Mn) ratio of less than 5. A developer characterized in that. 5. An image forming method for developing an electrostatic latent image on a photoreceptor with a toner image, wherein the toner has a BET value specific surface area of 5 m ² / g or more and a shape factor of 1.01 to 1. 5
Which is a toner for developing an electrostatic image, which is 6. An image forming method for developing an electrostatic latent image on a photoconductor with a toner image, wherein the toner has a BET value specific surface area of 5 m ² / g or more and a weight average molecular weight (Mw) / number average. An image forming method, which is an electrostatic charge image developing toner containing a resin having a molecular weight (Mn) ratio of less than 5. 7. An image forming method for transferring a toner image formed on an image support onto a transfer material, wherein the toner has a BET value specific surface area of 5 m ² / g or more and a shape factor of 1.01. An image forming method, which is a toner for developing an electrostatic charge image containing a resin of 1.5 to 1.5. 8. An image forming method for transferring a toner image formed on an image support onto a transfer material, wherein the toner has a BET value specific surface area of 5 m ² / g or more and a weight average molecular weight (Mw). An image forming method comprising: a toner containing a resin having a number average molecular weight (Mn) ratio of less than 5. 9. An image forming method of cleaning a toner remaining on the support after transferring a toner image formed on the image support onto a transfer material, wherein the toner is BE.
T value specific surface area of 5 m ² / g or more and shape factor of 1.0
An image forming method, wherein the toner is 1 to 1.5. 10. An image forming method comprising: cleaning a toner remaining on the support after transferring a toner image formed on the image support onto a transfer material.
An image forming method comprising a resin containing a resin having an ET value specific surface area of 5 m ² / g or more and a weight average molecular weight (Mw) / number average molecular weight (Mn) ratio of less than 5.