JPH09288381A - Electrostatic developing method and nonmagnetic one-component electrostatic developer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain good image quality, storage property at high temp. and high humidity, low temp. fixing property and a prolonged life. SOLUTION: By this method, a developer layer regulating member is pressed to a developer carrying body, and the carrying body is relatively moved to the regulating member to pass a one-component electrostatic developer essentially comprising toner particles in the pressed part. In the process to pass the developer, a developer layer is formed on the carrying body and the developer on the carrying body is transferred to an electrostatic latent image holding member in a facing zone with the electrostatic latent image holding member to visualize the image. In this method, the developer used contains toner particles containing at least a boron-contg. org. material expressed by the formula in a polyester-based binder resin and a fine particle additive having <=100m<2> /g specific surface area measured by nitrogen adsorption method. In the formula, R1 , R41 are independently hydrogen atoms, alkyl groups, or substd. or unsubstd. aromatic rings (including condensed rings), R2 , R3 are independently substd. or unsubstd. aromatic rings (condensed rings), and X<+> is a cation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dry electrostatic image developing method and 1 used in electrophotography, electrostatic recording and the like.
The present invention relates to a component electrostatic developer.

[0002]

2. Description of the Related Art Generally, in the electrophotographic system, an electrostatic latent electric image is formed by various means on a photoconductor (usually a photosensitive drum processed into a drum shape) containing various photoconductive substances, and the electrostatic latent image is formed. The electrostatic latent image is developed with a developer made of powder, and if necessary, the powder is transferred onto a substrate such as paper or film, and then fixed by a method such as pressing or heating. As the developer, a two-component developer composed of a carrier such as iron powder or ferrite powder and a toner and a one-component developer (non-magnetic or magnetic toner) not requiring a carrier are known.

As a developing method using a one-component developer,
A developer layer is adhered and formed on the surface of a developer carrier, and the developer is transferred by contacting it with an electrostatic latent image holding member such as a photoconductor, or by transferring the developer in a non-contact manner. Flying development methods are known. The electrostatic force control method for transferring the developer may be a method of forming a DC electric field between the developer carrying member and the latent image holding member or a direction toward the latent image holding member by applying an AC bias to the carrying member. A method is known in which an electric field is applied alternately to the direction of travel.

As a method of forming a developer layer on the developer carrying member, the developer carrying member is opposed to the developer layer thickness regulating member and is relatively moved to regulate the amount of the developer when passing through the opposed area. However, a method of forming a developer layer on the carrier is common. In the two-component developing method using magnetic carrier particles and the developing method using magnetic toner, the developer is magnetically attracted to a carrier (magnet roller) having a magnetic field generating means on the back surface of the carrier to regulate the carrier. A general method is to form a developer layer by passing the member through a gap keeping an appropriate distance.

When a non-magnetic developer such as a non-magnetic one component is used or a magnetic restraining force is not used, it is necessary to form the developer layer by Coulomb force due to frictional charge. In these cases, a sufficient amount of electrostatic charge cannot be secured just by passing through the gap as in the above, and the developer layer thickness may become non-uniform or the developer may be scattered to the periphery.
Therefore, in the case of a method that does not use magnetic force, the developer layer thickness regulating member is generally pressed against the developer carrier. That is, the developer is carried by the carrier, and by passing while pressing the pressing portions of the regulating member and the carrier,
A stable developer layer can be formed by forming a proper developer layer thickness and at the same time obtaining a sufficient frictional charge by the friction energy when the pressing portion is expanded.

The toner is a black toner containing a black dye or pigment such as carbon black, a monocolor toner used for monochromatic development or the like, and a full color development using cyan, magenta and yellow toners (black toner if necessary) in combination. Toner can be roughly classified. In the case of mono-color toners and full-color toners, there are restrictions on the materials that can be contained in the developer in order to obtain the desired hue. Generally, in order to improve the triboelectric chargeability of the toner, a charge control agent is contained in the toner. The charge control agent used for the color toner is generally colorless or white or a very pale color.

On the other hand, as a method for producing a toner, a pulverized toner production method for obtaining toner particles having a desired particle size by pulverizing a toner raw material which is obtained by mixing and kneading a binder resin and other components, cooling and solidifying, and a necessary method are required. There is known a method for producing a polymerized toner in which various components and a monomer of a binder resin raw material are dispersed to carry out a polymerization reaction to synthesize toner particles.

As a pulverization method for producing pulverized toner, a coarsely pulverized toner raw material is jetted together with a gas from a nozzle and pulverized by collision between raw material particles or collision with a collision plate, or a high-speed impact member. A mechanical crushing method of crushing is known. In the pulverized toner raw material, only particles having a desired particle diameter are selected by a classification step to obtain toner particles. As the toner for the developer for dry electrostatic image development, those having an average particle size of about 5 to 20 μm are usually used.

[0009]

In recent years, personalization,
With market demands such as space saving, downsizing of copiers, printers, etc. tends to be promoted. Further, in a full-color electrophotographic apparatus, it is necessary to arrange developing tanks for three or four colors in the apparatus, and further downsizing of the developing tank is required. However, the most commonly used two-component developing method conventionally requires a developing chamber for stirring a mixture of carrier particles and toner particles and a replenishing toner chamber for replenishing consumed toner. The function of controlling the mixing ratio of the toner and the carrier in the chamber is also required, and there are many problems from the viewpoint of downsizing and simplification.

In order to avoid these problems, the magnetic one-component method which does not use carrier particles has been widely used for personal use. However, although it is necessary to include a ferromagnetic component in the toner particles for one-component magnetic component, a colorless or light-colored ferromagnetic component is not generally known,
It is difficult to use magnetic single component development for full color development. Under such circumstances, a non-magnetic one-component developing system that does not use a ferromagnetic component or a magnet roller has been attracting attention. The non-magnetic one-component development method includes a flight development method and a contact development method, but these methods are generally unsuitable for analog image expression that requires gradation expression of photographs, but edge effects peculiar to electrophotography ( There is little phenomenon that toner is excessively developed on the black and white boundary of a printed image), and the thickening of printed characters does not easily occur, so it is suitable for digital expressions such as laser printers.

However, the problem of the non-magnetic one-component system occurs when the above-mentioned pressed developer layer thickness regulating member is used. That is, when a pressing force sufficient to form a uniform layer without toner scattering around is applied to the layer thickness regulating member, the toner is fused to the developer carrier or the layer thickness regulating member due to friction energy, or due to heat. Aggregation occurs, finely crushed, and fatal problems occur. If a hard toner having a high glass transition point or a high softening point is used to avoid these problems, the heat fixing performance is deteriorated, and a high temperature and a large amount of energy are required to sufficiently fix the toner on paper or the like.

However, from the viewpoint of energy saving,
Low temperature fixing is currently an essential performance requirement. A polyester resin is preferably used as a binder resin in order to obtain a toner that is strong in a developing device relatively close to room temperature and easily melts in a fixing temperature range of about 90 ° C. or higher.
However, the polyester-based binder resin has the following two drawbacks.

In many cases, the polyester resin has a hydrophilic group, and when a toner containing such a polyester resin as a main component is stored under high temperature and high humidity, the phenomenon of solidification is likely to occur. This tendency is remarkable as compared with the toner using the styrene acrylic resin. Further, the polyester-based resin is liable to cause ionic cross-linking and the like, and if the material to be dispersed and contained in the toner is erroneously selected, the glass transition point and the softening point are rapidly increased and the heat fixing performance is deteriorated. Such a phenomenon remarkably occurs depending on the type of the charge control agent that has been conventionally used.

Under the above-mentioned conditions, a binder resin which does not cause fusion, agglomeration, or fine pulverization, and which satisfies the fixability at low temperature is used, and at the same time the storability at high temperature and high humidity is ensured.
It is extremely difficult to design a toner having good triboelectrification performance and a clear image quality, and improvement of the chemical composition of the developing agent is desired. The charge control agent has been improved as a compositional improvement to improve the triboelectrification characteristics.However, in the case of a color toner, there are restrictions due to the color and also due to the above-mentioned restriction of ionic cross-linking. Limited.

[0015]

DISCLOSURE OF THE INVENTION The inventors of the present invention have made extensive studies in order to solve the above problems and obtain a high performance phenomenon agent. As a result, a toner using an organic substance of a specific composition as a charge control agent. The present invention has been achieved by using particles and specific particulate additives. That is, the gist of the present invention is that the developer layer thickness regulating member is pressed against the developer carrying member, and the carrying member moves relatively to the regulating member, so that the one-component static component containing toner particles as a main component. In the process in which the electro-developer passes through the pressing portion, a developer layer is formed on the carrier, and the developer on the carrier is transferred to the electrostatic latent image holding member in the area facing the electrostatic latent image holding member. In the electrostatic developing method of forming an image, toner particles containing at least a boron-containing organic compound represented by the following general chemical formula dispersed in a polyester binder resin, and fine particles having a specific surface area of 100 square m / g or less by a nitrogen adsorption method are added. Developing method using a one-component electrostatic developer containing at least a developing agent

[0016]

Embedded image

(In the formula, R ₁ and R ₄ each represent a hydrogen atom, an alkyl group, a substituted or unsubstituted aromatic ring (including a condensed ring), and R ₂ and R ₃ each represent a substituted or unsubstituted aromatic ring. (Including a condensed ring) and X ⁺ represents a cation), good image quality, storability at high temperature and high humidity,
It realizes low temperature fixability and long life.

Further, the toner content in the developer is 0.0% by weight.
By containing the fatty acid metal salt in an amount of 1 to 5% by weight, "white background fog" was reduced and higher image quality could be obtained.
According to the present invention, good image formation can be realized in a state where the developer carrying member and the electrostatic latent image holding member are in contact with each other.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The toner used in the present invention is a fine powder in which a polyester binder resin, a colorant, a charge control agent, a release agent as required, and other substances are dispersed. As the polyester-based binder resin among the toner constituent components, various known ones suitable for the toner can be used. For example, non-crosslinkable polyester resin,
Examples thereof include crosslinkable polyester resins.

The crosslinkable polyester resin used in the present invention comprises a divalent carboxylic acid monomer, a divalent alcohol monomer, a trivalent or higher polyvalent carboxylic acid monomer and a polyhydric alcohol monomer. It is obtained by polycondensation of As the dihydric alcohol monomer, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-
Butanediol, neopentyl glycol, 1,4-butenediol and other diols, bisphenol A, polyoxyethylenated bisphenol A, polyoxypropyleneized bisphenol A and other etherified bisphenols, and other divalent alcohol monomers Is mentioned. Two
Examples of the carboxylic acid monomer having a valence include those containing isophthalic acid, terephthalic acid, adipic acid, sebacic acid, diphenic acid, naphthalenedicarboxylic acid, cyclohexanedicarboxylic acid, or anhydrides or lower alkyl esters of these acids as main components. Can be mentioned. Examples of the trivalent or higher polycarboxylic acid include trimellitic acid, cyclohexanetricarboxylic acid, naphthalenetricarboxylic acid, butanetricarboxylic acid, hexanetricarboxylic acid, octanetetracarboxylic acid, anhydrides of these acids, and others. Examples of the trihydric or higher polyhydric alcohol monomer include trimethylolethane, trimethylolpropane, glycerin and pentaerythritol.

The non-crosslinkable polyester resin used in the present invention is obtained by polycondensation containing a divalent carboxylic acid monomer and a divalent alcohol monomer as main components. Also,
It is not limited to use one kind at a time, but two or more kinds may be used together. As the binder resin used for full color where glossiness and transparency are required, those which are non-crosslinkable and have a narrow molecular weight distribution are preferable. The weight average molecular weight is preferably 5 times or less the number average molecular weight, and further 3
It is more preferably not more than double.

The weight average molecular weight and the number average molecular weight of the binder resin can be measured by gel permeation chromatography (hereinafter referred to as GPC) under the following conditions.
That is, at a temperature of 25 ° C., a solvent (tetrahydrofuran) was flowed at a flow rate of 1 ml / min to give a concentration of 0.4 g / d.
1 of the tetrahydrofuran sample solution as the sample weight,
Inject mg and measure. Further, in measuring the molecular weight distribution of a sample, the molecular weight distribution of the sample is included within the range in which the logarithm of the molecular weight and the count number of the calibration curve made by several kinds of monodisperse polystyrene standard samples are linear. Select the measurement conditions. In this measurement, the reliability of the measurement is based on the NBS706 polystyrene standard sample (Mw = 288000, Mn = 13700) measured under the above-mentioned measurement conditions.
0, Mw / Mn = 2.11), Mw / Mn is 2.11 ±
It can be confirmed by being 0.10.

Then, the softening point of the developer produced by using the binder resin is a value measured by the flow tester method,
It is preferably 150 ° C. or lower, more preferably 135 ° C. or lower. If it exceeds 150 ° C, sufficient low-temperature fixability cannot be obtained, and the fixing strength tends to deteriorate, such being undesirable. As a binder resin used for full color where gloss and transparency are required, 120
C. or less is preferable, and 110.degree. C. or less is more preferable. The lower the softening point is, the better the fixing property is, and it is preferable. However, as the softening point is lowered, the glass transition point described later is also lowered.

The glass transition temperature of the developer produced using the binder resin is preferably such that the transition start (inflection point) measured by a differential thermal analyzer is 50 ° C. or higher, and 60 ° C. or higher. Are more preferred. When the glass transition temperature is less than 50 ° C., thermal stability during long-term storage is poor,
There is a problem in use due to aggregation and solidification of the toner. 7 more
When the temperature is 0 ° C. or higher, there is a margin for fusing the toner and pulverizing the fine powder, but the softening point also increases as the glass transition point increases, so that the fixability tends to deteriorate.

As the colorant, any suitable pigment or dye may be used so far as it is a conventionally used one. For example, titanium oxide, zinc white, alumina white, calcium carbonate, navy blue, carbon black, phthalocyanine blue, phthalocyanine green, Hansa yellow G, rhodamine dyes and pigments, chrome yellow, quinacridone, benzidine yellow, rose bengal, triallyl methane dyes. , Anthraquinone dyes, monoazo and disazo dyes and pigments are used alone or appropriately mixed depending on the color of the corresponding toner.

The content of the colorant may be an amount sufficient to color the toner so that a visible image can be formed by development, and is, for example, 3 to 20 parts by weight based on 100 parts by weight of the binder resin. Preferably. The charge control agent used in this toner is

[0027]

[Chemical 6]

(In the formula, R ₁ and R ₄ each represent a hydrogen atom, an alkyl group, a substituted or unsubstituted aromatic ring (including a condensed ring), and R ₂ and R ₃ each represent a substituted or unsubstituted aromatic ring. (Including a condensed ring) and X ⁺ represents a cation). This organic substance is colorless and is suitable for use as a color toner. The addition amount of this organic substance is 0.
2 to 10% by weight is preferable, and 0.5 to 6% by weight is more preferable.

Further, it may be used in combination with other charge control agents. Other charge control agents include JP-A-3-37183.
Metal-containing azo dyes described in JP-B No. 2-16916, salicylic acid metal complexes described in JP-B-55-42752, etc., salicylic acid metal salts described in JP-A-63-163374, etc. Examples thereof include calixarene compounds containing no metal element described in Kaihei 5-119535. When used in combination for color, colorless or light-colored ones are preferable, and colorless or light-colored ones are known as salicylic acid metal complexes, salicylic acid metal salts, and calixarene compounds. However, some of these charge control agents which can be used in combination, when used in a polyester resin, cause ionic cross-linking to deteriorate the fixing performance, so that sufficient caution is required in using them. When a charge control agent that may cause ionic cross-linking is also used, it is limited to a small amount that does not impair the fixability.

As a method of incorporating the above charge control agent into the toner, there are a method of adding it inside the toner and a method of adding it externally, but the case of internally adding it is common. In addition, known auxiliary agents that can be internally added to the toner for the purpose of improving thermal characteristics and physical characteristics can be used. For example, polyalkylene wax, paraffin wax, and higher fatty acid can be used as a release agent. , Fatty acid amides, and the like.
The amount added is 100 parts by weight of the binder resin,
0.1 to 10 parts by weight is preferable. In the case of using for full color where glossiness and transparency are required, use of a large amount of these auxiliaries may be harmful.

In the case of the method for producing a toner by a pulverization method, the above components may be kneaded with a kneader or the like, cooled, pulverized, and classified. The average particle size of the toner is preferably 5 to 20 μm. Generally, a method using a Coulter counter is widely used for the particle diameter of the toner. The average particle size of the toner used in this invention is Coulter Counter TA
A toner particle was dispersed in Isoton using an II-type 100 μm aperture, and the toner particle size distribution was measured using channels 3 to 16 and determined by volume averaging.

The softening point of the toner was measured using the flow tester method. Flow tester (Shimadzu CFT50
In 0), using a nozzle with a diameter of 1 mm and a length of 1 mm,
The heating element is set to 80 ° C. and 1 g of toner is added. Press the plunger lightly and heat it for 300 seconds, then 20k
A pressure of g / cm 2 is applied and the temperature is raised at a rate of 6 ° C./min. The toner is softened by the temperature rise and is pushed out from the nozzle, and the plunger is lowered. The temperature at which the plunger falls from the start to the end of the descent is the softening point.

The glass transition point of the toner is about 20 m using a differential thermal analyzer (DT-30 manufactured by Shimadzu Corporation).
g into the sample cell and set in the measuring section, once at 10 ° C /
After heating to 100 ° C. at a temperature rising rate of 10 minutes and cooling to room temperature, the temperature is raised again at 10 ° C./minute, and tangent lines are drawn from smooth curve portions before and after the inflection temperature portion of the DTA curve at this time, The intersection of these tangents is taken as the glass transition point.

Even in the case of a developer containing a toner as a main component and a fine particle additive or a fatty acid metal salt mixed therein, the softening point and the glass transition point are dominated by the thermal characteristics of the toner. The difference between the case of measurement and the case of measurement with the developer as the mixture is within the measurement error range.
In the developing method using the developer obtained by adding the fine particle additive to the toner particles, white background fog may occur. In such a case, white background fog can be reduced by adding a fatty acid metal salt.

Specific surface area 100 added in the present invention
As the fine particle additive having a square m / g or less (preferably 70 square m / g or less), inorganic fine particles or organic fine particles are used. As the inorganic particles, metal particles and oxide particles are known, and inorganic oxide particles are particularly preferable. As the inorganic oxide fine particles, oxides of silicon, titanium, aluminum, magnesium, iron, zinc, cerium and the like, or composite oxides thereof can be used. As the organic fine particles, resin powder such as methylmethacrylate beads can be used. The surface of these may be surface-treated with a silane coupling agent, a titanium coupling agent, silicone, or other resin. The addition amount is 0.1 in the developer.
〜5wt%, more preferably 0.2〜2wt% add significant effect.

In order to improve the fluidity of the developer, 1
You may use together 2 or more types of fine particle additives of 00 square m / g or more. For the specific surface area by the nitrogen adsorption method, an appropriate amount of sample is put into a cell and degassing is performed at 200 ° C. for 10 to 20 minutes using a Shimadzu Micromeritics Flowsorb 2300 type, and the specific surface area (square m / g) is measured. If degassing at 200 ° C is not possible due to possible decomposition of the sample, degas at a temperature below that value and repeat the measurement on the same sample. Use the measured value when the value is stable. .

As the fatty acid metal salt used in the present invention, a saturated or unsaturated fatty acid metal salt having preferably 8 to 35 carbon elements can be used. As the metal salt, lithium, sodium, potassium, copper, rubinium, silver, magnesium, calcium, zinc, strontium, cadmium, barium, mercury, aluminum, chromium, tin, titanium, zirconium, lead, manganese,
Including iron, cobalt, nickel salts and mixtures thereof,
It is not limited to these. The particle size of the fatty acid metal salt powder before addition is usually about 0.2 to 30 μm, but it is not particularly limited because it has a crushing effect when mixed with toner particles. However, it is more preferable that the amount of coarse powder is small and the particle size is small because uniform dispersion is easy at the time of mixing. The amount of the fatty acid metal salt added depends on the particle size, etc.
0.01-5 parts by weight, more preferably 0.05-1.
2 parts by weight exerts a remarkable effect. Among the fatty acid metal salts, zinc stearate is particularly preferable.

It is preferable that the toner, the fatty acid metal salt, and the inorganic oxide fine particles are mixed in a predetermined amount, and the mixture is stirred and mixed by a high-speed stirrer or the like that gives a shearing force to the powder such as a Henschel mixer or a super mixer. At this time, since heat is generated inside the external additive machine and aggregates are easily generated, it is preferable to adjust the temperature by means such as cooling the periphery of the container part of the external additive machine with water. The internal material temperature is set to be equal to or lower than the glass transition temperature of the resin, and a control temperature of about 10 ° C. or lower, particularly a control temperature of 15 ° C. or lower is preferable. In practice, the material temperature may be regarded as the temperature inside the tank of the external addition machine.

A developing method will be described by taking the developing device of FIG. 1 as an example. The developer carrying member 1 used in the present invention usually has a cylindrical or cylindrical surface as a carrying surface. The material may be either an elastic body or a rigid body, but a method using an elastic body is generally used in the contact developing method. The surface may be provided with an appropriate surface roughness for the purpose of improving the transportability of the developer. Further, it is necessary to consider a material capable of obtaining an appropriate frictional charge with the toner particles. In the case of non-magnetic one-component contact type development, a conductive rubber roller (such as silicone rubber having conductive particles dispersed therein) is used as a general form of the elastic developer carrier. A dielectric layer may be provided on the surface layer of the conductive rubber.

Developer layer thickness regulating member 2 used in the present invention
Examples include various types such as a rectangular rod-shaped rigid body, a protrusion-shaped elastic body, a leaf spring that uses the surface or tip of a leaf spring, a roller, or a combination thereof. The developer layer thickness regulating member 2 is pressed against the developer carrier by its own elastic force, the elastic force of the developer carrier 1, an external force, or a combined force thereof.

Regarding the electrical characteristics of the regulating member, when a voltage is applied to an insulating material or an electrically conductive material, or a material which is an electrically conductive material, but is electrically not connected to anything and floats. There are various types, but in the case of an insulator or even if a conductor is not applied with a voltage, "white background fog" may occur due to the oppositely charged toner. In such a case, the addition of the fatty acid metal salt of the present invention is effective. By relatively moving the developer carrier relative to this linear pressing so as to slide in a direction perpendicular to the linear carrier, the developer particles pass while spreading the pressing portion, and the developer particles are evenly coated on the developer carrier 1. Form the layers. The thickness of the developer layer and the charge amount of the toner are controlled by the form, pressure, composition, and applied voltage of the pressing portion. Overall, the higher the pressure, the smaller the developer layer thickness applied and the higher the amount of charge, but the form,
Since the composition and applied voltage are complicated physical and chemical phenomena, they cannot be discussed in general.

The electrostatic latent image holding member 3 used in the present invention
Uses a photoreceptor with a layer of selenium, an organic photosensitive material, etc. on the surface of a conductive base material, or a master with an insulator layer on the surface of a conductive base material. Form a latent image pattern. As a general form used in a copying machine or a laser printer, a cylinder made of metal such as aluminum or a sheet of a resin film on which a thin film of aluminum is formed and coated with a photosensitive material is used. When an organic photosensitive material is used as the photosensitive material, the photosensitive layer has a relative dielectric constant of about 1 to 5 and is generally used with a layer thickness of about 10 to 50 μm.

In the image forming step, a latent image having an electrostatic charge distribution is formed on the electrostatic latent image holding member 3 by uniform charging and exposure procedures according to the generally used principle of xerography. At this time, the maximum potential on the electrostatic latent image holding member 3 is
About 100 to 1200 V in absolute value based on the conductive base material,
More preferably, it is controlled to be about 300 to 900V.

On the other hand, as described above, the developer carrying member 1 has
The developer is applied by the developer layer thickness regulating member 2. 500 V is applied between the developer carrying member 1 and the developer layer thickness regulating member 2 when no voltage is applied or when they are short-circuited to have the same potential.
There are cases where the voltage below is applied. Further, the developer supplying means 4 may be provided on the upstream side of the developer layer thickness regulating member 2 in the relative movement direction of the developer carrier 1.

As the developer supplying means 4, a means is used in which, in addition to the force by which the developer adheres to the developer carrier 1 due to its own weight and fluidity, the developer positively moves toward the carrier. For example, a method may be used in which a developer is contained in a sponge-like or brush-like member and rubbed against the developer carrying member 1. The friction at this time may be used to accelerate the triboelectrification of the developer.
A conductive material may be used for the developer supplying means 4, and a voltage may be applied between the developer and the carrier so that the developer applies an electrostatic force toward the carrier. Further, since the roller-shaped endless developer carrier 1 is generally used, the carrier 1 to which the remaining developer after the development on the latent image holding member 3 adheres returns to the portion of the supply means 4. It also comes as a cleaning means. On the contrary, in order to positively utilize the effect, a voltage may be applied so that a force is applied in a direction in which the developer is separated from the carrier 1. Also, an alternating electric field may be applied for the purpose of both cleaning and supply, or for the purpose of charging the developer.

When the developing device having the configuration shown in FIG. 1 is used, the developer leak seal member 5 is generally attached because the developer may leak from the lower gap of the developer carrying member 1. Through the above steps, the electrostatic latent image holding member 3 having a latent image formed thereon is opposed to the developer carrying member 1 having a developer layer formed thereon, and at least toner particles in the developer are transferred to visualize the latent image.

At this time, in flight development, 50 to 50
A gap of 0 μm is formed and transferred by electrostatic force. In the case of contact development, the toner particles are pressed through the developer layer, and the toner particles corresponding to the latent image pattern are transferred by electrostatic force. It is common to maintain the potential of the carrier at a potential between the latent image potential to which the toner is to be transferred and the latent image potential to be the white background. In the case of a monochromatic copying machine or laser printer, the toner transferred to the latent image pattern is generally further transferred to a transfer material such as paper or film.

In the case of full-color development, the transfer of multiple colors may be repeated on the transfer material. However, by using an intermediate transfer member, the transfer of each color from the electrostatic latent image holding member to the intermediate transfer member is repeated to transfer the colors. After overlapping, the full-color image may be visualized by transferring to a transfer material at once. In these transfer steps, a method in which the surface of the transfer source and the surface of the transfer destination are brought into contact with each other and a charge is applied from the back surface by corona discharge, or a method in which a conductive transfer roller is pressed to apply a voltage is generally used. The toner transferred onto the transfer material is generally fused and fixed by heat in a fixing device.

[0049]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the scope of the invention. In addition, in the following Examples and Comparative Examples, simply saying “part” means “part by weight”.

Example 1 A cyan toner was prepared and tested with the following formulation.

[0051]

[Table 1]

Was mixed with a twin-screw kneading extruder, pulverized and classified to obtain toner particles having an average particle size of about 9 microns. The softening point was 129 ° C and the glass transition point was 62 ° C. To 100 parts of the toner particles, 0.4 parts of silica fine powder having a specific surface area of 40 square meters / g, the surface of which was hydrophobized with trimethylsilane group, was added and mixed with a Henschel mixer to obtain a developer.

The present developer is put in a container and 3.5 g /
After applying a pressure of square cm, the state of the developer taken out was observed, and no agglomeration or the like was observed, and a good powder state was maintained. This developer was filled in a developing device of a laser printer LP-1500 manufactured by Seiko Epson Corporation, and an actual copying test was conducted. This printer uses a non-magnetic one-component developing system, and a developer spring thickness member is used as the developer layer thickness regulating member. An OPC photosensitive drum is used as the electrostatic latent image holding member, and is an apparatus of the type that forms an image on a transfer material such as paper or an OHP sheet by a roller transfer method. As a result of the live-action test, good image quality was maintained up to 3000 sheets.

Example 2 Using the toner particles procured in Example 1, a specific surface area of 60 square meters / having a surface of 40 square meters / g which is hydrophobized with silicone oil instead of silica fine powder having a specific surface area of 40 square meters / g.
Example 1 except that 0.4 parts of silica fine powder of g was used.
Similarly, the developer was procured. This developer was used in the same manner as in Example 1
When a storage stability test was performed at 0 ° C. and 90% RH for 5 hours,
A small amount of agglomeration had occurred, but it was about to collapse when pressed lightly with a finger, and it was a problem as a developer. As in Example 1, the developer was subjected to an actual copying test using a laser printer LP-1500 manufactured by Seiko Epson Co., Ltd. up to 3000 sheets, and good image quality was maintained.

Comparative Example 1 Using the toner particles procured in Example 1, a specific surface area of 170 square m / g whose surface is hydrophobized with trimethylsilane groups instead of silica fine powder having a specific surface area of 40 square m / g. A developer was procured in the same manner as in Example 1 except that 0.4 part of the silica fine powder of was used. This developer had better fluidity than the developer of Example 1, but Example 1
Similarly, when a storability test was conducted at 50 ° C. and 90% RH for 5 hours, lumps were formed.

Comparative Example 2 Using the toner particles procured in Example 1, a specific surface area of 120 square meters, the surface of which is hydrophobized with dimethylsilane groups, instead of silica fine powder having a specific surface area of 40 square meters / g.
A developer was procured in the same manner as in Example 1 except that 0.4 parts of silica fine powder / g was used. When this developer was subjected to a storage stability test at 50 ° C. and 90% RH for 5 hours in the same manner as in Example 1, a lump was generated.

Comparative Example 3 Toner particles were procured in the same manner as in Example 1 except that 2 parts of the charge control agent Bontron E-81 manufactured by Orient Chemical Industry was used in place of the charge control agent A. Softening point is 155
The glass transition point was 68 ° C. Bontron E-8
It is considered that the glass transition point increased because ionic crosslinking occurred due to the addition of 1. The toner particles were mixed with silica in the same manner as in Example 1 to obtain a developer. This developer was subjected to a live-copy test using a laser printer LP-1500 manufactured by Seiko Epson Corp. as in Example 1.
Although a clear image was obtained, the image on the transfer paper was easily peeled off by rubbing it with a finger.

Comparative Example 4 Toner particles were procured in the same manner as in Example 1 except that 2 parts of the charge control agent Bontron E-84 manufactured by Orient Chemical Industry Co., Ltd. was used in place of the charge control agent A. Softening point is 144
The glass transition point was 65 ° C. Bontron E-8
It is considered that the softening point and the glass transition point increased because ionic crosslinking occurred due to the addition of 4. The toner particles were mixed with silica in the same manner as in Example 1 to obtain a developer. When this developer was subjected to a live-copy test using a laser printer LP-1500 manufactured by Seiko Epson Corporation as in Example 1, a clear image was obtained, but it was easy to peel off the image on the transfer paper with a finger.

Example 3 Toner particles were procured in the same manner as in Example 1 except that the cyan pigment was changed to a magenta pigment and the amount of the charge control agent A was changed to 5 parts. Softening point is 131 ° C, glass transition point is 62
° C. To 100 parts of the toner particles, 0.4 part of the silica fine powder having a specific surface area of 40 square m / g used in Example 1 and 0.8 part of the silica fine powder having a specific surface area of 60 square m / g used in Example 2 were added. In addition, the developer was procured by mixing with a Henschel mixer as in Example 1. When this developer was subjected to a storage stability test at 50 ° C. and 90% RH for 5 hours in the same manner as in Example 1, no agglomeration was observed and a good powder state was maintained. As in Example 1, the developer was subjected to an actual copying test using a laser printer LP-1500 manufactured by Seiko Epson Co., Ltd. up to 3000 sheets, and good image quality was maintained.

Example 4 To 100 parts of the toner particles procured in Example 3, 1 part of the fine silica powder having a specific surface area of 40 square meters / g used in Example 1 and zinc stearate (AC manufactured by SYNPRO, Inc. of the United States of America) were used.
F) and 1 part were added and mixed in the same manner as in Example 1 with a Henschel mixer to obtain a developer. When this developer was subjected to a storage stability test at 50 ° C. and 90% RH for 5 hours in the same manner as in Example 1, no agglomeration was observed and a good powder state was maintained. This developer is a laser printer 401 manufactured by IBM
9 (equipped with a non-magnetic one-component type developing device, the developer layer thickness regulating member has a rectangular rod-shaped rigid body pressed against the developing roller), with no voltage applied to the developer layer regulating member. When the actual shooting test was performed up to 2000 sheets, good image quality was maintained.

Example 5 Zinc stearate of Example 4 (USA SYNP
RO ACF) small part zinc stearate instead of 1 part (US SYNPRO DLG-20)
A live-action test was performed in the same manner as in Example 4 except that the copy number was changed to 0.1.
When the number of sheets reached to 00, good image quality was maintained.

Example 6 A cyan toner was prepared and tested with the following formulation.

[0063]

[Table 2] Polyester resin B 100 parts (constituent monomers: polyoxypropyleneized bisphenol A, terephthalic acid, trimellitic acid 1.5 mol% weight average molecular weight / number average molecular weight = 2.9) Cyan pigment 5 parts Charge control agent Part A

Was mixed with a twin-screw kneading extruder, pulverized and classified to obtain toner particles having an average particle size of about 9 microns. The softening point was 104 ° C and the glass transition point was 62 ° C. To 100 parts of toner particles, 0.2 parts of small-sized zinc stearate (DLG-20 manufactured by SYNPRO, USA) and 1.5 parts of silica fine powder having a specific surface area of 40 square m / g used in Example 1 were added. A developer was obtained by mixing with a Henschel mixer as in Example 1. Sony Tektronix full color laser printer Phaser
It was filled in a cyan developing device of 540JS, and a real shooting test was conducted with a pattern in which other colors were not printed. The result of the live-action test,
Good images were kept up to 4000 sheets.

[0065]

According to the present invention, good image quality, storability under high temperature and high humidity, low temperature fixing and long life can be realized.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a developing method that can be used in the present invention.

[Explanation of symbols]

 1 developer carrier 2 developer layer thickness regulating member 3 electrostatic latent image holding member 4 developer supply means 5 developer leakage prevention seal member 6 electrostatic developer

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Claims (11)

[Claims] 1. A one-component electrostatic developer containing toner particles as a main component when a developer layer thickness regulating member is pressed against a developer carrier and the carrier moves relatively to the regulating member. Forms a developer layer on the carrier in the step of passing through the pressing portion, and transfers the developer on the carrier to the electrostatic latent image holding member in the area facing the electrostatic latent image holding member to visualize the developer. In the electrostatic development method, toner particles containing at least a boron-containing organic compound represented by the following general chemical formula dispersed in a polyester-based binder resin and a specific surface area by a nitrogen adsorption method of 10
An electrostatic developing method, which comprises using a one-component electrostatic developer containing at least 0 square m / g or less of a fine particle additive. Embedded image (In the formula, R ₁ and R ₄ each represent a hydrogen atom, an alkyl group, a substituted or unsubstituted aromatic ring (including a condensed ring), and R ₂ and R ₃ each represent a substituted or unsubstituted aromatic ring (condensed ring). Is also included), and X ⁺ represents a cation.) 2. The boron-containing organic substance dispersedly contained in the toner particles is represented by the following chemical formula, and the content of boron-containing organic substance in the toner particles is 0.2 to 10% by weight.
The electrostatic development method according to claim 1, wherein Embedded image 3. The electrostatic developing method according to claim 1, wherein the fine particle additive is an inorganic oxide, and the addition amount is 0.1 to 5% by weight based on the weight of the toner particles. 4. The one-component electrostatic developer contains at least 0.01 to 5 wt% of a fatty acid metal salt based on the weight of toner particles, according to any one of claims 1 to 3. The electrostatic development method described. 5. The electrostatic developing method according to claim 1, wherein the one-component electrostatic developer is a non-magnetic one-component developer. 6. The developer layer carried by the developer carrying member is in contact with the electrostatic latent image holding member in a region where the developer carrying member and the electrostatic latent image holding member are opposed to each other. 6. The electrostatic developing method according to any one of items 1 to 5. 7. A toner particle containing at least a boron-containing organic compound represented by the following general chemical formula dispersed in a polyester binder resin, and a fine particle additive having a specific surface area of 100 square meters / g or less measured by a nitrogen adsorption method. A non-magnetic one-component electrostatic developer characterized by containing. Embedded image (In the formula, R ₁ and R ₄ each represent a hydrogen atom, an alkyl group, a substituted or unsubstituted aromatic ring (including a condensed ring), and R ₂ and R ₃ each represent a substituted or unsubstituted aromatic ring (condensed ring). Is also included), and X ⁺ represents a cation.) 8. The boron-containing organic substance contained in the toner particles is represented by the following chemical formula, and the content of boron-containing organic substance in the toner particles is 0.2 to 10% by weight. The non-magnetic one-component electrostatic developer according to claim 7. Embedded image 9. The non-magnetic one-component electrostatic according to claim 7, wherein the fine particle additive is an inorganic oxide, and the addition amount is 0.1 to 5% by weight of the weight of the toner particles. Developer. 10. The toner has a weight of 0.0% by weight in the developer.
The non-magnetic one-component electrostatic developer according to any one of claims 7 to 9, which contains at least 1 to 5% by weight of a fatty acid metal salt. 11. A color toner containing a colored organic material in toner particles.
The non-magnetic one-component electrostatic developer according to any one of 0.