JPH03293364A - Image forming method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming method in electrophotography. More specifically, the present invention relates to an image forming method that includes a charging step in which a charging member to which a voltage is externally applied is brought into contact with a member to be charged to perform charging.

[Prior Art] Corona dischargers have conventionally been known as charging means in electrophotographic devices, etc., but corona dischargers have problems such as having to apply a high voltage and generating a large amount of ozone. are doing.

Therefore, recently, consideration has been given to using contact charging means without using a corona discharger.

Specifically, a voltage is applied to a conductive roller, which is a charging member, and the roller is brought into contact with a photoreceptor, which is an object to be charged, so that the surface of the photoreceptor is charged to a predetermined potential. If such contact charging means is used, the voltage can be lowered compared to a corona discharger, and the amount of ozone generated can also be reduced.

For example, in Japanese Patent Publication No. 50-13661, it is possible to apply a low voltage when charging photosensitive paper by using a roller whose core metal is coated with a current visitor made of nylon or polyurethane rubber.

However, in the above-mentioned conventional example, when the core metal is coated with nylon, it does not have the elasticity of rubber or the like, so it cannot maintain sufficient contact with the object to be charged, resulting in charging failure. On the other hand, if the core metal is coated with polyurethane rubber, the softening agent impregnated into the rubber material will seep out and cause problems! When a photoconductor is used as the F electric body, there is a problem in that the charging member sticks to the photoconductor at the abutting portion when the photoconductor is stopped, or the image becomes blurred in that area. In addition, if the softener in the rubber-based material of the charging member seeps out and adheres to the surface of the photoreceptor, the resistance of the photoreceptor becomes low and image deletion occurs, making it unusable in severe cases or remaining on the surface of the photoreceptor. Toner is f
It may adhere to the surface of the chamber member, causing a filming phenomenon. When a large amount of toner adheres to the surface of the charging member, the surface of the charging member becomes insulated, the charging ability of the charging member is lost, and the IF charge on the surface of the photoreceptor becomes non-uniform, which affects the image.

On the other hand, when a developing process using a negatively charged non-magnetic color toner is combined, various additional problems arise.

This toner does not contain a magnetic substance, and from the viewpoint of color saturation, it often does not contain a conductive substance such as carbon black. For this reason, there is no part from which charging can leak, especially when the grinding temperature is low and the humidity is low, and the charging tends to become excessive compared to normal toner. This tendency is particularly noticeable in negatively charged color toners. This is largely due to the negatively charged hydrophobic silica used as a fluidity imparting agent.

Furthermore, in recent years, there has been a strong demand for higher image quality of copier images. On the other hand, the aim is to achieve high image quality by reducing the toner particle size, but this reduction in toner particle size also increases the surface area of the toner, which increases the IF charge amount.
It is easy to become excessive.

As described above, when charging becomes excessive, toner becomes difficult to transfer from the photoreceptor, and the amount of toner remaining on the photoreceptor increases, making it easy for toner to be collected in the cleaning process. In addition, because it has a strong 4E charge and adheres to the photoreceptor,
Poor cleaning is likely to occur.

Toner that cannot be completely removed in these cleaning steps adheres to the charging member, resulting in a decrease in fE performance and filming on the photoreceptor.

Also, if the particle size is small, there are many contact points between the toners, so
Toner fluidity deteriorates. Therefore, toner aggregation occurs during the cleaning process, resulting in poor cleaning.

Therefore, in order to prevent excessive charging, addition of conductive powder, addition of low chargeability substances, addition of opposite polarity substances, etc., have been carried out, but each has its own drawbacks.

First, when conductive powder is added, the amount of charge decreases significantly under high humidity, causing problems such as uneven image density and fogging. Further, since conductive powder is generally colored, it has a negative effect on the color of color toner.

In addition, addition of low chargeability substances (for example, JP-A-56-92
545, JP-A-60-217368, etc.)
However, in order to obtain a sufficient fluidity imparting effect, a large amount is required to be added, and the amount of charge is often reduced too much, or a sufficient fluidity imparting effect is often not obtained.

Further, when adding a substance of opposite polarity, if the substance of opposite polarity contains coarse particles, the toner may aggregate around the coarse particles, and a toner mass of opposite polarity may be generated. This toner mass is developed in a non-image area and deteriorates the image quality. Therefore,
A step is required to remove coarse particles or toner clumps.

[Problems to be Solved by the Invention] The present invention has been made in view of the above points, and it is possible to maintain sufficient contact between the charging member and the charged object, and prevent the charging member and the charged object from sticking together. In addition, the plasticizer contained in the conductive rubber of the charging member is attached to the charged object, thereby preventing the toner from sticking to the surface of the charging member and preventing charging defects and charging unevenness due to toner filming on the charged object. A charging process that does not cause electrification, high resolution, and high definition images can be obtained, and after the development, transfer and cleaning processes, there is very little residue left on the charged object, and there is no residue on the surface of the charging member or the charged object. Development process using toner that does not cause sticking,
An object of the present invention is to provide an image forming method having a transfer step and a cleaning step.

[Means and effects for solving the problems] The features of the present invention include: (1) A charging step in which a charging member to which a voltage is applied from the outside is brought into contact with a charged object to perform IF charging; is a conductive rubber layer and an outer side of the conductive rubber layer,
and a charging process characterized by having a releasable film on at least a portion that contacts the charged object; (2) the toner for developing the charged object is made of at least non-magnetic colorant-containing polyester resin particles; An insulating non-magnetic color toner having a coloring agent, wherein the colorant-containing polyester resin particles have a volume average diameter of 4 to 10 μm and whose main components are a diol component and a dicarboxylic acid component. , and at least a portion of -COOH is substituted with a functional group containing N, and at least one of the flow improvers has an absolute value of IF charge of 20 μc/g or less when triboelectrically charged with a carrier. An image forming method characterized by comprising a developing step of performing development with a characteristic color toner, (1) a transfer step, and (2) a cleaning step.

As a result of intensive studies on the charging stability and charge-up prevention of negatively chargeable polyester color toners for electrostatic charge development, the present inventors have determined that at least a portion of the residual -COOH of the polyester can be transferred to more N of amines, azines, and pyridinium salts. By replacing it with a functional group containing
It has been found that charging stability can be achieved over a long period of time under a wide range of environments.

That is, by replacing at least a part of -Coo)I with a functional group containing N, the toner becomes difficult to absorb moisture under high humidity, and at the same time, the effect of promoting the rise of IFK by rubbing with the functional group containing N is achieved. also occurs. This suppresses a decrease in charging to some extent under high humidity conditions.

In addition, polyester resins generally tend to become excessively negatively charged under low humidity conditions, but this phenomenon can be countered by treatment with a modifier containing N, due to the positively charging ability of the modifier. Electrostatic charges are neutralized, which is very effective in suppressing charge-up, and at the same time provides good cleaning performance.

Furthermore, in order to make the present invention even more effective, the total acid value and hydroxyl value should be 3 to 2 omgKOH/g, preferably 4 to 15 087 g, to provide a toner with sufficient environmental stability of charging. A color toner with good colorant dispersibility is achieved and is desirable.

Replacing at least a part of this -COOH with a functional group containing N is disclosed in Japanese Patent Application Laid-Open No. 81-14644, etc., but these are only intended for positively chargeable toners, and this is not the case in this invention. This invention is completely different from the negatively chargeable color toner used in the invention.

JP-A-62-195678, JP-A-62-19567
No. 8, JP-A-62-195680, JP-A-62-19
According to No. 5681, JP-A-62-195682, etc.
It is said that the amount of charge of polyester resin decreases if the amount of terminal groups, especially the amount of carboxyl groups, is reduced too much, but the present inventor has found that by containing a suitable charge control agent when forming a toner, the amount of charge can be sufficiently reduced. It was found that the value of Further, according to the above-mentioned publication, it is also stated that the ratio of hydroxyl value to acid value is adjusted to 1.2 or more for the purpose of improving fluidity and lowering the minimum fixing temperature, but the present inventor has developed an additive as described below. It has been found that by using the toner, stable fixing performance can be obtained because appropriate fluidity and appropriate filling state of the toner layer on the transfer material can be achieved.

In the present invention, in order to replace at least a part of -COOH with a functional group containing N, a functional group reactive with -COOH N)+2. A modifier having NHR, NR2, etc. may be treated after the polyester polymerization reaction.

Diol components of the polyester resin used in the present invention include ethylene glycol, propylene glycol,
1.3-butanediol, 1.4-butanediol, 2
, 3-butanediol, diethylene glycol, dipropylene glycol, triethylene glycol, 1.5-
Bentanediol, 1,6-hexanediol, neopentyl glycol, pentaerythritol diallyl ether, trimethylene glycol, 2-ethyl-1,3-
Hexanediol, hydrogenated bisphenol A, or a bisphenol conductor represented by the following formula: is 2
~10. ) and other diols.

In addition, dicarboxylic acid components include fumaric acid, maleic acid,
Unsaturated dicarboxylic acids such as citraconic acid and itaconic acid, or their acid anhydrides, dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, azelaic acid, or their acid anhydrides, and aromatic acids such as phthalic acid and terephthalic acid. Examples include dicarboxylic acids.

The diol component used in the present invention is 40 to 80
The content of the dicarboxylic acid component is preferably 60 to 40 mo1%, preferably 55 to 45 mo1%.

Examples of the N-containing modifier used in the present invention include jetanolamine, dimethylaminoethanol, triethanolamine, polyalkyleneamine, diethylenetriamine, triethylenetetramine, and the like.

The method for producing polyester resin is as follows.

The reaction is carried out under an inert gas atmosphere (often in the presence of nitrogen gas) at normal pressure to reduced pressure (0 to -760 mmH20).

60-270℃ while stirring, preferably 80-220℃
The reaction is carried out for 10 to 30 hours. Water or alcohols produced by condensation polymerization are continuously discharged from the system together with the inert gas while supplying an inert gas into the system.
Allow condensation polymerization to proceed.

For example, acid and alcohol are charged into a reaction vessel equipped with a stirrer, a condenser, a thermometer, and an inert gas introduction tube. Next, inert gas is introduced to perform gas replacement. After the completion of gas replacement, the inert gas is continued to flow, and the reaction temperature is raised to a predetermined temperature, and the condensation polymerization reaction is carried out with stirring for 10 to 30 hours. Water or alcohol produced by the condensation polymerization reaction is condensed and recovered in a condenser outside the system. At the end of the reaction, a modifier is added to treat the -COOH group.

After completion of the reaction, the produced water or the remaining modifier when the added modifier is in excess are evaporated under reduced pressure and condensed outside the system using a condenser and recovered. Thereafter, the temperature is lowered to room temperature to obtain a polyester resin.

Here, due to its properties, the polyester resin in the present invention preferably has a total acid value and hydroxyl value of 3 to 20 mgKOH/g, and if it exceeds 0.87 g in 20 mg, the number of carboxyl groups or hydroxyl groups increases. The dependence of electricity on the environment becomes greater, and there are greater restrictions on the colorants, external additives, etc. that can be used.

On the other hand, if the amount is less than 3 mg OH/8, the colorant dispersed in the resin tends to be unevenly dispersed, which may cause problems such as toner scattering and fogging.

The method for measuring acid value and hydroxyl value used in the present invention is shown below.

To measure the acid value, measure 2 to 10 g of sample at 200 to 300 mj.
) into an Erlenmeyer flask, methanol:toluene=
Approximately 50m of mixed solvent of 30:70! Additionally, the resin is dissolved. If the solubility seems poor, a small amount of acetone may be added. Pre-standardized N using a mixed indicator of 0.1% bromthymol blue and phenol red.
/10 Potassium hydroxide - Titrate with an alcohol solution, and determine the acid value from the consumption amount of the alcohol potassium solution using the following formula (I).

Acid value = KOH (mj! number) X N X 56.1/
Sample weight...(I) (N is a factor of N/10 KOH) In addition, to measure the hydroxyl value, the sample is heated with an excess acetylating agent, such as acetic anhydride, to acetylate, and the resulting acetyl After measuring the saponification value of the compound, it is calculated according to the following formula (!I).

(However, A represents the saponification value after acetylation, and B represents the saponification value before acetylation.) The toner according to the present invention may contain a charge control agent in order to stabilize the charging characteristics. In this case, a colorless or light-colored charge control agent that does not affect the color tone of the toner is preferred. Examples of negative charge control agents include organometallic complexes such as metal complexes of alkyl-substituted salicylic acid (for example, chromium complexes or zinc complexes of di-tert-butylsalicylic acid). When the negative charge control agent is added to the toner, it is preferably added in an amount of 0.1 to 10 parts by weight, preferably 0.5 to 8 parts by weight, per 100 parts by weight of the binder resin.

When preparing a two-component developer by mixing with the toner according to the present invention, the mixing ratio is 2 as the toner concentration in the developer.
．． Good results are usually obtained with 0 to 10% by weight, preferably 3 to 9% by weight. If the toner concentration is less than 2.0% by weight, the image density will be too low to be practical, and if it exceeds 10% by weight, capri and in-machine scattering will increase and the useful life of the developer will be shortened.

As the coloring agent used in the present invention, a wide variety of known dyes and pigments can be used, such as phthalocyanine blue, industhrene blue, peacock blue, permanent red, lake red, rhodamine lake, banza yellow, permanent yellow, and benzine yellow. The content thereof is 12 parts by weight or less, preferably 0.5 to 9 parts by weight, based on 100 parts by weight of the binder resin so as to sensitively reflect the transparency of the OHP film.

The flow improver used in the present invention must contain at least one type of agent whose absolute value of charge when triboelectrically charged with a carrier is 20 μc/g or less, preferably 10 μc/g or less.

More preferably, the fluidity improver is a wood-friendly inorganic oxide having an absolute value of triboelectric charge with the carrier of 20 μc/g or less and a specific surface area of 30 to 200 m2/g by BET method;
A negatively charged hydrophobic inorganic oxide having an absolute value of friction lfN with the carrier of 50 μc/g or more and a specific surface area of 80 to 300 m'/g by the BET method is applied to the colorant-containing resin particles from 0.3 to Use 2% by weight.

Even if the charging ability of the binder resin is stabilized as in the present invention, if silicic acid fine powder, which is commonly used as a fluidity improver, is used alone, the fluidity will certainly improve, but the charging properties As a result, the toner's cleaning properties tend to become excessively high, especially under low humidity conditions, and as a result, the cleaning properties of the toner are impaired. This tendency becomes more noticeable as the particle size of the toner is reduced and the amount of fine silicic acid powder used increases.

However, as in the present invention, by containing at least one flow improver with weak charging ability as a flow improver,
This made it possible to achieve both charging characteristics and cleanability.

Examples of flow improvers include, but are not limited to, the following: For example, Aj20s
, TiOz, GeO2, ZrO2, 5C20s,
Metal oxides such as Hf (:h, SiC, Tic, W2
Carbide such as C and 5L3N4. There are nitrides such as Ge and N4, among which ^j203. TiO2,5c
z03. Since ZrO*, GaO2, and Hf0z are colorless or white, they are suitable for use in color toners without adversely affecting the color. Also especially AJ2
0s, TiO2, and Zr0m are more preferable because they can be easily produced with a suitable particle size by a gas phase method, and
Hydrophobic treatment may also be performed. The smaller the particle size of the added particles, the better, and in the present invention, a fluidity imparting agent having a specific surface area in the range of 3 om2/g to 200 II12/g is used as measured by the BET method. More preferably som
'/g or more is preferable, and the finer the particle size, the better the fluidity characteristics of the toner.

As the above-mentioned hydrophobic inorganic oxide, it is particularly preferable to use treated silica fine powder obtained by hydrophobicizing silica fine powder produced by gas phase oxidation of a silicon halide compound. Among the treated silica fine powders, it is particularly preferred that the silica fine powders be treated so that the degree of hydrophobicity as measured by a methanol titration test is in the range of 30 to 80.

Hydrophobization is achieved by chemical treatment with an organosilicon compound that reacts with fine silica powder or physically adsorbs it.

In a preferred method, fine silica powder produced by vapor phase oxidation of a silicon halide is treated with an organosilicon compound.

Examples of such organosilicon compounds are hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane,
Allyl phenyldichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, ρ-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilylmercaptan, trimethylsilylmercaptan, triorganosilylacrylate , vinyldimethylacetoxysilane, dimethylethoxysilane, dimethyldimethoxysilane, diphenyljethoxysilane,
Hexamethyldisiloxane, 1,3-divinyltetramethyldisiloxane, 1,3-diphenyltetramethyldisiloxane and St. There are dimethylpolysiloxanes containing hydroxyl groups bonded to . These are 1f! Alternatively, a mixture of two or more types may be used.

Commercially available products include Taranox-500 (Talco),
Examples include AERO5IL R-972 (Japan Aerosil Co., Ltd.). The amount added is 0 to the resin particles.
．． It is 3 to 2% by weight.

The amount added is also related to the particle size distribution of the resin particles described later, but if it is less than 0.3% by weight, appropriate fluidity cannot be achieved, whereas if it is more than 2% by weight, toner scattering and fogging may occur. Harmful effects are likely to occur.

If necessary, additives may be mixed into the toner of the present invention within a range that does not impair the properties of the toner. Examples of such additives include lubricants such as Teflon, zinc stearate, and polyvinylidene fluoride; Or a fixing aid (for example, low molecular weight polyethylene, low molecular weight polypropylene)
etc.

In producing the toner of the present invention, the constituent materials are thoroughly kneaded using a thermal kneader such as a hot roll, kneader, or extruder, and then mechanically crushed or classified, or magnetic particles are added to the binder resin solution. After dispersing materials such as powder,
There are various methods such as spray drying, or polymerization toner manufacturing method, which obtains a toner by mixing a specified material with monomers that constitute the binder resin and then polymerizing this emulsified suspension. Can be applied.

In the color toner of the present invention, the volume average particle size of the toner is 6 to 10 μm, 15 to 40% by number of toner particles having a particle size of 5 μm or less, and 0.1 to 5% of toner particles having a particle size of 12.7 to 16.0 μm. The effect is more remarkable when toner particles of 6.35 to 10.1 μm have a particle size distribution that satisfies the following formula: 0% by volume, 1.0% by volume or less of particles of 16 μm or more.

The toner having the above particle size distribution is capable of faithfully reproducing the latent image formed on the photoconductor, and is also excellent in reproducing halftone dots and minute latent images such as digital dots, especially highlights Provides an image with excellent gradation and resolution. Furthermore, it maintains high image quality even when copying or printing is continued, and even in the case of high-density images, it is possible to perform good development with less toner consumption than conventional non-magnetic toner, making it economical. This has advantages in terms of flexibility and miniaturization of the copying machine or printer main body.

The reason why such an effect is obtained in the color toner of the present invention is not necessarily clear, but it is presumed as follows.

Conventionally, in color toners, toner particles of 5 μm or less are difficult to control the amount of charge, impair the fluidity of the toner, and are components that cause the toner to scatter and contaminate machines, and also cause image fogging. It was believed that it was necessary to actively reduce the number of

However, according to studies conducted by the present inventors, it has been found that toner particles of about 5 μm are an essential component for forming high-quality images.

For example, by using a two-component developer containing a non-magnetic toner and a carrier with a particle size distribution ranging from 0.5 μm to 30 μm, the surface potential on the photoreceptor is changed, and a large number of toner particles are easily developed at a large development potential. The developed toner on the photoreceptor is developed by changing the latent image potential on the photoreceptor, from contrast to halftone to a latent image of a small minute dot in which only a few toner particles are developed. When the particles were collected and the toner particle size distribution was measured, the result was 8.
It was found that there were many toner particles with a diameter of .mu.m or less, and in particular, there were many toner particles with a diameter of about 5 .mu.m on the latent image of minute dots. In other words, when toner particles with a particle size of about 5 μm are smoothly supplied to develop a latent image on a photoreceptor, an image that is faithful to the latent image, does not protrude from the latent image, and has truly excellent reproducibility can be obtained. It is something that can be done.

Also, toner particles of 12.7μ++-16.0μm are 5
This is related to the necessity of the presence of toner particles with a particle size of about μm, but non-magnetic toner particles with a particle size of 5 μm or less certainly have the ability to faithfully reproduce the latent image of minute dots, but they themselves It has a fairly high cohesiveness, which may impair the fluidity of the toner.

The present inventors attempted to further improve fluidity by adding two or more of the above-mentioned inorganic oxides for the purpose of improving fluidity, but the method of adding inorganic additives alone was insufficient. It was confirmed that the conditions for satisfying all items such as image density, toner scattering, and fogging were very narrow. Therefore,
The present inventors further investigated the particle size distribution of toner and found that toner particles with a particle size of 5 μm or less
It has been found that by containing 0.1 to 5.0 volume % of toner particles with a diameter of 12.7 to 16.0 μm in addition to the content of 0.1 to 5.0 volume %, fluidity can be further improved and high image quality can be achieved. That is, it is thought that this is because toner particles in the range of 12.7 to 16.0 μm have appropriately controlled fluidity compared to toner particles of 5 μm or less, and as a result,
Even when copying or printing is continued, sharp images with high density and excellent resolution and gradation are provided.

Furthermore, for toner particles of 0.35 to 10.1 Atm, their volume % (V), number % (N), and volume average particle diameter (d
It is more desirable that the color toner of the present invention satisfies the following relationship between (v) and (1).

While studying the state of particle size distribution and development characteristics, the present inventors found that there is a state of particle size distribution most suitable for achieving the purpose as shown by the above formula.

In other words, when the particle size distribution is adjusted by numerical wind classification, the above value is large, which means that the number of toner particles of about 5 μm that faithfully reproduce the minute dot latent image increases, and the above value is small. On the contrary, this is understood to indicate that toner particles with a size of about 5 μm are reduced.

Therefore, when dv is in the range of 6 to 10 μm and the above relational expression is further satisfied, good toner fluidity and faithful latent image reproducibility can be achieved.

For toner particles with a particle size of 16 μm or more, 1.
It is preferable that the amount is 0% by volume or less, and as little as possible.

The configuration of the present invention will be explained in more detail. 5μm
Toner particles with the following particle sizes account for 15-40% of the total number of particles
%, more preferably 20 to 35% by number. When the number of toner particles with a particle size of 5 μm or less is 15% or less, there are few non-magnetic toner particles that are effective for high image quality.
In particular, as toner is used by continuing to copy or print out, effective toner particle components decrease, the balance of toner particle size distribution worsens, and image quality gradually deteriorates. If the content is more than 40% by number, toner particles tend to aggregate with each other, resulting in toner agglomerates larger than the original particle size, resulting in rough image quality, lowering resolution, or reducing the edge portion of the latent image. The difference in density between the image and the inside becomes large, and the image tends to look hollow.

In addition, particles in the range of 12.7 to 16.0 um are 0.1 to 5
．． The content is preferably 0% by volume, preferably 0.2 to 3.
0% by volume is good. When the amount is more than 5.0% by volume, image quality deteriorates and more development than necessary occurs, that is, too much toner is applied, leading to an increase in toner consumption. On the other hand, 0.
If it is less than 1% by volume, the image density will decrease due to a decrease in fluidity.

Further, it is preferable that the amount of toner particles having a particle size of 16 μm or more is 1.0% by volume or less, more preferably 0.6% by volume or less, and if it is more than 1.0% by volume, it will interfere with fine line reproduction. In addition, during transfer, the presence of coarse toner particles of 16 μm or more protruding from the thin layer of toner particles developed on the photoreceptor results in subtle interference between the photoreceptor and the transfer paper via the toner layer. Irregular adhesion causes fluctuations in transfer conditions, which tends to cause defective transfer images. Also, the volume average diameter of the toner is 6 to 1
It is 0 μm, preferably 7 to 9 μm, and this value cannot be considered in isolation from the above-mentioned components. If the volume average particle diameter is less than 6 μm, in applications with a high image area ratio such as graphic images, the amount of toner applied to the transfer paper is small, which tends to cause problems such as low image density. This is considered to be due to the same reason as the reason why the density inside the edge portion of the latent image decreases as described above. When the volume average particle diameter is 10 μm or more, the resolution is not good, and even if copying is good at the beginning, image quality tends to deteriorate with continued use.

As described above, by using this toner, it is possible to obtain a copy image with high resolution, high definition, and high quality, and it is also possible to prevent the amount of charge from becoming excessive even under low humidity. Therefore, the transfer efficiency is increased, the amount of residual toner on the photoreceptor is reduced, and the adhesion between the residual toner and the photoreceptor is reduced, so that poor cleaning and leakage from the cleaner can be prevented. Furthermore, since sufficient fluidity is obtained, there is little aggregation in the cleaner, and poor cleaning due to toner aggregation can be prevented. Furthermore, sufficient charge can be secured even under high humidity, so
No scattering or fogging occurs.

The particle size distribution of toner can be measured by various methods.
In the present invention, a Coulter counter was used.

In other words, the measuring lid is Coulter Counter T^-I.
Using type I (manufactured by Coulter), an interface for outputting the number distribution volume distribution (manufactured by Nikkaki) and a CX-1 personal computer (Canon) were connected, and the electrolyte was 1% using primary sodium chloride. NaC1) Prepare an aqueous solution. As a measurement method, the electrolytic aqueous solution 100 to 150
0.1 to 5 mj+ of a surfactant, preferably an alkylbenzene sulfonate, as a dispersant is added to +u, and further 2 to 20 mg of the measurement sample is added. The electrolytic solution in which the sample was suspended was dispersed for about 1 to 3 minutes using an ultrasonic disperser, and then dispersed using the Coulter Counter TA-H type using a 100 μm aperture, based on the number of particles.
The particle size distribution of the 40 μm particles was measured and the values according to the invention were determined therefrom.

The color toner of the present invention can be applied to both one-component development method and two-component development method.

When the color toner of the present invention is used as a two-component developer, an electrically insulating resin is used as a coating resin on the surface of the carrier, which is appropriately selected depending on the toner material and the carrier core material. In the present invention,
In order to improve the adhesion to the surface of the carrier core material, it is preferable to contain at least one monomer selected from at least acrylic acid (or its ester) and methacrylic acid (or its ester). is necessary. In particular, when polyester resin particles with high negative chargeability are used as a toner material, it is preferable to further copolymerize with a styrene monomer in order to stabilize charging, and the copolymerization weight ratio of the styrene monomer is 5-70. ! It is preferable to set it as amount %.

The average molecular weight of the above copolymer is determined to be a number average molecular weight of 10.
00-35,000 preferably 17,000-24.0
00. Weight average molecular weight is 25,000 to 100,000
It is preferably 49,000 to 55,000.

Coating resin connector for carrier core material that can be used in the present invention
Examples of styrene yarn threads include styrene monomer, chlorostyrene monomer, α-methylstyrene monomer, styrene-chlorostyrene monomer, etc., and examples of acrylic threads include acrylic ester monomer (methyl acrylate monomer, acrylic ethyl acrylate monomer, butyl acrylate monomer, octyl acrylate monomer, phenyl acrylate monomer, 2-ethylhexyl acrylate monomer), etc.
Examples include methacrylic acid ester monomers (methyl methacrylate monomer, ethyl methacrylate monomer, butyl methacrylate monomer, phenyl methacrylate monomer).

As the magnetic particles used in the present invention, for example, surface-oxidized or unoxidized metals such as iron, nickel, copper, zinc, cobalt, manganese, chromium, rare earths, and their alloys or oxides can be used.

Moreover, there are no special restrictions on the manufacturing method.

The measurement method according to the present invention will be described below.

■Frictional charge measurement The measurement method will be explained in detail using the front page.

FIG. 1 is an explanatory diagram of an apparatus for measuring the amount of toner charge. First, a mixture of a fluid improver and a carrier whose weight ratio is 1:49 is poured into a metal measuring device 2 with a 500 mesh screen 3 at the bottom and a polyethylene film having a capacity of 50 to 100 ml. bottle and shake by hand for about 10 to 40 seconds to remove the mixture (developer).
Add about 0.5 to 1.5 g and cover with a metal lid 4. The weight of the entire measuring container 2 at this time is measured as L (g). Next, in the suction device 1 (at least the portion in contact with the measurement container 2 is an insulator), suction is performed from the suction lower, and the air volume control valve 6 is adjusted to set the pressure of the vacuum gauge 5 to 250 mmAq.

In this state, suction is performed for a sufficient period, preferably 2 minutes, to remove the toner by suction. The potential of the electrometer 9 at this time is V (volt)
shall be. Here, 8 is a capacitor whose capacitance is C (μF
). Also, weigh the entire measurement container after suction W2
<g). The amount of triboelectric charge of this toner (μc/
g) is calculated as shown below.

(However, the measurement conditions are 23° C. and 60% R1.) The carrier used for the measurement is EFV200/300 (manufactured by Powdertic Co., Ltd.).

Next, a specific example of a contact charging process applicable to the present invention will be described.

The 11F electric device according to the present invention is, for example, '! It is similar to diagram J2. Reference numeral 13 denotes a photosensitive drum which is a charged member and rotates in the direction of the arrow. 14 is the photosensitive drum 13
A charging roller is a charging member that is brought into contact with a predetermined pressure. E is a source unit that applies voltage to the charging roller 14, and a predetermined voltage is applied to the core metal 14a of the charging roller 14.
supply to. Although E indicates a DC voltage in the 's2 diagram, it may be a DC voltage superimposed with an AC voltage.

In the present invention, a conductive rubber layer 14b is provided on the metal core 14a, and a surface layer 14c, which is a releasable film, is further provided on the circumferential surface of the conductive rubber layer 14b. The reason for this is that by providing a releasable film outside the conductive rubber layer, the softener from the conductive rubber does not seep into the portion that comes into contact with the photoreceptor, which is the object to be charged. Therefore, it is possible to prevent image blur due to lower resistance of the photoreceptor when the softener adheres to the photoreceptor, and a decrease in charging ability due to filming of residual toner on the photoreceptor.
Decrease in charging efficiency is suppressed.

Furthermore, by using a conductive rubber layer for the charging roller, sufficient contact between the charging roller and the photoreceptor can be maintained, and charging failures will not occur.

In the present invention, a charging device as shown in FIG. 3 can also be used. Although a blade-shaped contact charging member is used here, the metal support member 14' is also supplied with voltage.
The conductive rubber 14'b is supported by a, and the photosensitive drum 1
By providing a surface layer, which is a releasable film, on the portion in contact with 3, the same effects as in the above example can be obtained.

In the above-described example, a roller-shaped or blade-shaped charging member is used, but the present invention is not limited to this, and the present invention can be practiced with other shapes as well.

In addition, in the example described above, the charging member is composed of a conductive rubber layer and a release film, but the charging member is not limited to this, and there is a high resistance between the conductive rubber layer and the surface layer of the release film to prevent leakage to the photoreceptor. It is preferable to form a layer, for example, a hydrin rubber layer that is subject to small environmental fluctuations.

Nylon resins PVDF (polyvinylidene fluoride) and PVDC (polyvinylidene chloride) can be used for the release film. Further, as the photoreceptor, OPC, amorphous silicon, selenium, ZnO, etc. can be used. In particular, when amorphous silicon is used for the photoreceptor, compared to when other materials are used, if even a small amount of the softener in the conductive rubber layer adheres to the photoreceptor, image fading will become severe. The effect of applying an insulating film is significant. Furthermore, the charging device of the present invention can also be used for transfer.

[Examples] The present invention will be described in detail below using Examples (manufacturing examples of polyester resins and examples of toners using the resins).

The above compounds were mixed at a molar ratio of 1:1 and placed in a 2 fL four-neck round bottom flask equipped with a thermometer, a Teflon-coated stirring blade, a glass nitrogen inlet tube, a condenser, and a pressure reduction device. After nitrogen gas was introduced through the glass introduction tube to create an inert atmosphere inside the reactor, the inside of the system was maintained at -753 mmH2O by adjusting the nitrogen gas introduction pulp and the opening degree of the pressure reduction adjustment valve. Thereafter, the reactor was placed in a mantle heater, and the condensation reaction was carried out while maintaining the temperature at 170°C for 20 hours. The pressure at this time was also maintained at -750 mmH,O.

This is called resin A.

After that, acetic acid was added to the system to obtain resin B.

Furthermore, jetanolamine was added to the system to obtain modified polyester resin C.

Separately, triethanolamine was added instead of jetanolamine to obtain a modified polyester resin. Table 1 shows the acid values and hydroxyl values of resins A-D.

Table 1 Example 1 was sufficiently premixed using a Henschel mixer, melt-kneaded at least twice using a three-roll mill, and after cooling, coarsely ground using a hammer mill to about 1 to 2 degrees of hardness, and then using an air jet method. It was pulverized using a pulverizer. Furthermore, the obtained finely ground product was classified and a particle size of 2 to 10 μm was selected so as to have the particle size distribution of the present invention, thereby obtaining colored, autopsy-acceptable resin particles.

Triboelectric charge amount of silica fine powder treated with 05 parts by weight of hexamethyldisilazane to 100 parts by weight of the above colorant-containing resin particles - 50 μc/g, triboelectric charge amount of alumina fine powder with BET specific surface area of 230 m27g and 0.5 parts by weight 1.7μc/
g, BET specific surface area xoom2/g was added externally to prepare a cyan toner.

This cyan toner is Met.

To 5 parts by weight of this cyan toner, a copolymer (number average molecular weight: 21,250
, i weight average molecular weight 52360) and weight average particle size 4
5 μm 135 μm or less 4.2%, 35-40 μm 19.
Cu- with a particle size distribution of 5%, 34 μm or more and 0.2%
A Zn-Fe based ferrite carrier coated with 0.5% carrier was mixed in a total amount of 100 parts by weight to prepare a developer.

Using this developer, the charging device of a commercially available plain paper color copying machine (Color Laser Copier 500, manufactured by Canon) was modified to have the configuration shown in FIG. 2, and images were printed. Second
In the figure, the outer diameter of the charging roller 14 was 12 mmφ, the conductive rubber layer 14b was made of EPDM, and the surface layer 14c was made of nylon resin with a thickness of 10 pm. Charging roller 1
The hardness of 4 is 54. 'J (ASKER-C).

The development contrast is 290V at 23℃/65% 20℃/10% below 350■ 30℃/80% below 250■ The applied voltage was adjusted so that

As a result, in each environment, the image density was stable at 1.45 to 1.55, and the image was clear with no fog. Furthermore, no cleaning defects occurred, and no decrease in charging efficiency was observed.

Compare ■'' Example 1 except that resin B is used in Example 1.
When I performed the image output in the same way as above, it was slightly lower than 15℃ and 710%! Contamination of the electric roller was observed, and filming occurred on the photoreceptor, resulting in image deterioration. Furthermore, the image density was 1.30, which was slightly lower than in Example 1.

Comparative Example 2 When image formation was performed in the same manner as in Example 1 except that the surface layer 14c was not provided in the charging equipment chamber of Example 1, toner fusion occurred on the photoreceptor. This is thought to be caused by the rubber softener in the charging roller.

Example 2 In the charging device of Example 1, the surface layer 14c is made of PVdF.
When the same procedure as in Example 1 was carried out except that Vd was increased, good results were obtained.

When image printing was carried out in the same manner as in Example 1 except that resin resin was used instead of resin C, the image density decreased by 0.05 at 15°C and 710%, and at 30°C/ Image density is 0. below 80%. Although the environmental characteristics were slightly deteriorated due to the high lO, it was sufficiently durable for practical use, and good images were obtained without poor cleaning or filming on the photoreceptor.

Large m (In Jll Hill Example 1, instead of Al2O2, T
A good result was obtained in the same manner as in Example 1 except that 0.4 parts by weight of the iO□ solid powder was used.

In Example 1, images were produced in the same manner as in Example 1 except that fine alumina powder was not used. During durability, filming occurred on the photoreceptor and image deterioration occurred.

IL Ri J Using the cyan toner of Example 1, a commercially available color copying machine (
Images were produced by modifying the developing device of a color laser copier 500 (manufactured by Canon) to have the configuration shown in FIG. 4 with the following conditions set.

That is, in Fig. 4, 22 is a sleeve (coating layer thickness: 13 μm) coated with phenol resin in which 40 parts by weight of molybdenum disulfide is dispersed on the surface of an aluminum cylinder.
It is. 24 is a urethane sponge roller. The developer applying blade 25 applies a linear pressure of 80 g/
It is in contact with cm. Further, the gap between the developer carrier and the latent image carrier was maintained at 250 μm, and the toner layer thickness was regulated at 50 μm. All other conditions are set on the copier itself.

As a result of a durability test of 5,000 sheets under each environment of 20℃/10%, 23℃/60%, and 50℃/80%, no sleeve contamination or sleeve fusion was observed in each environment, and the image The density was stable at l, 40 to 1.55, and clear images with no fog were obtained.

[Effects of the Invention] In contrast to the image forming method having the above-mentioned charging step, the present invention performs development in the developing step using a toner with improved resin particles and flow improver. A high-resolution, high-definition image can be obtained in which there is very little toner remaining on the body, and the toner does not stick to both the surface of the charging member and the surface of the charged object.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an apparatus for measuring the tribocharge amount of toner, and FIGS. 2 and 3 are 1! suitable for the present invention. : is an explanatory diagram of the electrical equipment room, and FIG. 4 is an explanatory diagram of a developing device suitable for the present invention.

Claims (3)

[Claims] (1) {1} A charging process in which a charging member to which a voltage is applied from the outside is brought into contact with the object to be charged, and the charging member is connected to a conductive rubber layer and a portion outside the conductive rubber layer. and a charging step characterized by having a releasable film on at least a portion that contacts the charged object; {2} The toner for developing the charged object is at least a non-magnetic colorant-containing polyester-based toner. An insulating nonmagnetic color toner comprising resin particles and a flow improver, wherein the colorant-containing polyester resin particles have a volume average diameter of 4 to 1.
0 μ, the main components are a diol component and a dicarboxylic acid component, and at least a part of -COOH is substituted with a functional group containing N, and at least one of the flow improvers has friction with the carrier. It is characterized by having a developing step of performing development with a color toner characterized in that when charged, the absolute value of the charge amount is 20 μc/g or less, {3} a transfer step and {4} a cleaning step. image forming method. (2) The volume average diameter of the toner is 6 to 10 μm, and 5 μm
15 to 40% by number of toner particles having a particle size of m or less,
12.7-16.0μm is 0.1-5.0% by volume, 16
Contains 1.0% by volume or less of micrometers or more, 6.35 to 10
．． Toner particles of 1 μm have the following formula 9≦(V×@d@v)/N≦14 [where V: volume % of toner particles having a particle size of 6.35 to 10.1 μm N: 6.35 to 10 .Number% of toner particles having a particle size of 1 μm @d@v: average volume diameter of all toner particles] A developing process, a transfer process, and a cleaning process performed using an electrostatic charge developing toner characterized by satisfying the following: The image forming method according to claim 1, comprising: (3) As a fluidity improver, the absolute value of triboelectric charge with the carrier is 20 μc/g or less and the specific surface area is 3 by BET method.
A negatively charged hydrophobic inorganic with a hydrophilic inorganic oxide of 0 to 200 m^2/g and a carrier with an absolute value of triboelectric charge of 50 μc/g or more and a specific surface area of 80 to 300 m^2/g by BET method. 0.3 of the oxide and colorant-containing resin particles.
Claim (1) characterized in that ~2% by weight is added.
Or the image forming method described in (2).