JPH0434440A - Non-magnetic toner and image forming method - Google Patents

Abstract

PURPOSE:To prevent the fixing of an electrifying member and an electrified body and to obtain an image having high resolution and high precision by using an insulated non-magnetic toner having resin particles incorporating a specified non-magnetic coloring agent and a flowability improver. CONSTITUTION:The toner is an insulated non-magnetic toner having the resin particles incorporating the non-magnetic coloring agent and the flowability improver. The resin particles incorporating the non-magnetic coloring agent have 6 - 10mum in a volume mean particle size, in which the constitution components are consisting essentially of a diol and dicarboxylic acid components and at least a part of -COOH is substituted with a functional group incorporating N. Besides at least one of the flowability improvers is fine silica powders treated with a silane coupling agent having a positively triboelectrified part and a negatively triboelectrified part and further treated with a silicone oil. The non-magnetic toner incorporating such fine silica powders is used. Thus the contact of the electrified member with the electrified body is kept sufficiently and the fixing of them is prevented, so that the image having high resolution and high precision is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a nonmagnetic toner and an image forming method in electrophotography.

[Prior Art] Corona dischargers are conventionally known as charging means in electrophotographic devices and the like. However, corona dischargers have problems such as the need to apply high voltage and the generation of a large amount of ozone.

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 dielectric material made of nylon or polyurethane rubber. However, in the above-mentioned conventional example, when the core metal is coated with nylon, it cannot maintain sufficient contact with the object to be charged because it does not have the elasticity of rubber or the like, 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 if a photoreceptor is used as the object to be charged, the charging member will stick to the photoreceptor at the contact area when the photoreceptor stops. do,
Alternatively, there is a problem in that the area causes image blurring. Additionally, 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 decreases and image deletion occurs, and in severe cases, the softener may become unusable or remain on the surface of the photoreceptor. Toner adheres to the surface of the charging member,
A filming phenomenon sometimes occurred. 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 surface of the photoreceptor becomes unevenly charged, which affects the image.

On the other hand, when a developing process using 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 are no parts that leak charge, especially under low temperature and low humidity conditions (and the charge tends to become excessive compared to normal toner).

In addition, polyester resins are often used as binder resins for full-color toners depending on conditions such as fixability, color mixing properties, and transparency, but toners made of polyester resins are generally not affected by temperature and humidity. Problems such as excessive charging under low humidity and insufficient charging under high humidity are particularly likely to occur.

Furthermore, for the purpose of improving various image characteristics such as resolution, density uniformity, and fog, it is widely used (though it is widely practiced) to externally add silica powder to impart fluidity to toner. The conventional silica fine powder has a large amount of charge under low humidity, which further exacerbates the above problems.

Furthermore, in recent years, there has been a strong demand for higher image quality of copier images. On the other hand, high image quality has been achieved by reducing the toner particle size, but this reduction in toner particle size also increases the surface area of the toner, which tends to result in an excessive amount of charge.

In this way, if the charging becomes excessive, it becomes difficult for toner to be transferred from the photoconductor, and as a result, there is a large amount of residual toner on the photoconductor, and the toner that cannot be collected in the cleaning process is ejected. Since the toner is strongly charged and adheres to the photoreceptor, cleaning failures are likely to occur.Toner that cannot be removed during these cleaning steps adheres to the charging member, resulting in a decrease in charging ability and filming on the photoreceptor.

Furthermore, if the particle size is small, there are many contact points between the toners, resulting in poor toner fluidity.As a result, toner aggregation occurs during the cleaning process, resulting in poor cleaning.

[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. Furthermore, it is used in an image forming method that has a charging step that prevents the plasticizer contained in the conductive rubber of the charging member from adhering to the charged object, and can obtain high-resolution, high-definition images, as well as development, transfer, and cleaning steps. A non-magnetic toner that hardly remains on the charged object after passing through the charging process, and as a result, does not stick to the surface of the charging member or the charged object, and the development process, transfer process, and cleaning using this toner. An object of the present invention is to provide an image forming method comprising steps.

[Means and effects for solving the problems] The present invention is characterized in that: first, it is an insulating non-magnetic toner having a small amount (both non-magnetic colorant-containing resin particles and a flow improver); The non-magnetic colorant-containing resin particles have a volume average particle diameter of 6 to 10.
μm, the main components are a diol component and a dicarboxylic acid component, and at least a part of -C0OH is N
furthermore, at least one of the fluidity improvers is a silica fine powder, and the silica fine powder is a silane coupling agent having a positive triboelectric charging site and a negative tribocharging site. Second, the non-magnetic toner is treated with a silicone oil fine powder, and the non-magnetic toner has a volume average particle size of 6 to 10 μm.
m, and 15 to 40 number % of particles with a particle size of 5 gm 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, particle size 6.35~
Third, the non-magnetic toner according to the first aspect, in which the toner particles of 10.1 μm satisfy the following formula, the amount of silicone oil treated is A/ 25±A/
30 parts by weight (A: specific surface area of silica fine powder), and the degree of hydrophobicity is 90% or more, the non-magnetic toner according to the first or second item. This is a charging process in which the object to be charged is charged by bringing it into contact with the object to be charged, and the object to be charged has a conductive rubber layer and a portion outside the conductive rubber layer with a small distance (in both cases, a portion that is in contact with the object to be charged is separated from the conductive rubber layer). A charging step in which a charging member having a moldable film is brought into contact with a charged object and a voltage is applied from the outside to perform charging; a developing step using the non-magnetic toner described in the first item above; a transfer step; and a cleaning step. An image forming method comprising steps.

That is, the present inventors proposed a charging process in which a charging member to which a voltage is applied from the outside is brought into contact with a charged object, and the charged object includes a conductive rubber layer and a portion outside the conductive rubber layer. In adopting a charging process in which a charging member having a releasable film on the part that contacts the charged object is brought into contact with the charged object and charged by applying a voltage from the outside, the development After considering what is necessary for a non-magnetic toner to produce high-resolution, high-definition, and high-quality images, as well as for it to have sufficient fluidity without becoming excessively charged even under low humidity conditions, we found that The inventors have discovered that it is possible to provide a toner that meets the above objectives by specifying the binder resin, adding a specific fluidity improver to the toner, and further specifying the particle size distribution of the toner.

The constituent elements and effects of the non-magnetic toner of the present invention will be explained below.

As a result of intensive studies on toner charging stability and charge-up prevention, the present inventors discovered that by replacing at least a portion of the residual -COOH in the resin with an N-containing functional group such as amine, azine, or pyridinium salt,
It has been found that charging stability can be achieved over a long period of time under a wide range of environments.

In other words, by replacing a portion of -C0OH with a functional group containing N, the toner becomes difficult to absorb moisture when placed at high temperatures, and at the same time, the rise of charging is promoted by rubbing with the functional group containing N. This also produces the effect of suppressing the drop in charging at high temperatures to some extent.

In addition, polyester resins generally tend to become excessively negatively charged under low humidity conditions, but this phenomenon can be moderated by treating with a modified agent containing N, due to the positive charging ability of the modified agent. Electrostatic charges are neutralized, which is very effective in suppressing charge-up, and at the same time, cleaning performance is also improved.

Furthermore, in order to make the present invention even more effective, the sum of the acid value and hydroxyl value should be 3 to 20 mgKOH/g, preferably 4 to 15 mgKOH/g! /g, a toner with sufficient charging environmental stability is achieved and is desirable.

The replacement of a small amount of -COOI with a functional group containing N is disclosed in JP-A-61-14644, etc.; This invention is completely different from the toner of the present invention.

JP-A-62-195676, JP-A-62-19567
No. 8, JP-A-62-195680, JP-A-62-19
According to No. 5681, JP-A-62-195682, etc.
It has been stated that if the amount of terminal groups, especially the amount of carboxyl groups, is reduced too much, the amount of charge of polyester resin decreases, 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 Furthermore, according to the above-mentioned publication, it is also stated that the ratio of the hydroxyl value to the acid value is adjusted to 1 to 2 or more for the purpose of improving fluidity and lowering the minimum fixing temperature. It has been found that by using the agent, stable fixing performance can be obtained because appropriate fluidity and appropriate filling state of the toner layer on the transfer material can be achieved.

Now, in the present invention, at least a part of 1000H is converted to N
In order to replace it with a functional group containing -C00I, a modifier having functional groups NH2, NHR, NR2, etc. that are reactive with -C00I may be treated after the polyester polymerization reaction.

The polyhydric alcohol component of the polyester resin used in the present invention includes 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,
Neopentene glycol, pentaerythritol diallyl ether, trimethylene glycol, 2-ethyl-1
, 3-hexanediol, hydrogenated bisphenol A, and bisphenol derivatives represented by the following formula; (wherein R is ethylene or propylene group, X and y are each an integer of 1 or more, and the average of value is 2
~10. ) and other diols.

In addition, as the dicarboxylic acid component, unsaturated dicarboxylic acids such as fumaric acid, maleic acid, citraconic acid, and itaconic acid, or acid anhydrides thereof, dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, azelaic acid, etc. Examples thereof include acid anhydrides, aromatic dicarboxylic acids such as phthalic acid and terephthalic acid, and the like.

The diol component used in the present invention is 40 to 60
mo1%, preferably 45-55 mo1%, dicarboxylic acid component 60-40 mo1%, preferably 55-55 mo1%
It is desirable that it be 45 mo1%.

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

Next, a method for producing such a polyester resin will be described. Under an inert gas atmosphere (often in the presence of nitrogen gas) at normal pressure to reduced pressure (0 to -760 mmHzO), the temperature is raised to 60 to 270°C, preferably 80 to 220°C, with stirring, for 10 to 30 hours. Perform a reaction. The water or alcohol produced by the condensation polymerization is continuously discharged from the system together with the inert gas while an inert gas is supplied into the system, so that the condensation polymerization proceeds.

For example, acid and alcohol are charged into a reactor equipped with a stirrer, a condenser, a thermometer, and an inert gas introduction tube. Next, inert gas is introduced to perform gas replacement. Even after the completion of gas replacement, the inert gas is continued to flow, 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 aggregated and recovered in a condenser outside the system. At the end of the reaction, a modifier is added to treat the -COD)] group.

After the reaction is complete, the water produced or the remaining alcohol if added is in excess, is evaporated under reduced pressure and collected outside the system by condensation using a condenser. Thereafter, the temperature is lowered to room temperature to obtain a polyester resin.

Here, due to its properties, the polyester resin according to the present invention preferably has a sum of acid value and hydroxyl value of 3 to 20 mgKOH/g, and if it exceeds 20 mgKO)1/g, the carboxyl group or hydroxyl value This increases the environmental dependence of charging, and there are greater restrictions on the colorants, external additives, etc. that can be used.

On the other hand, if it is less than 3 mgKOf(/g), the dispersion in the resin tends to become non-uniform, which may cause problems such as toner scattering and fogging.

In this way, by using the above-mentioned polyester resin, it is possible to satisfy the fixing properties, color mixing properties, and transparency required for full-color toners, while suppressing the drop in charging under high humidity, and allowing charging even under low humidity. It is possible to obtain toner in which the amount is not excessive.

However, in order to improve various image characteristics such as resolution, density uniformity, or fog, negatively charged silica fine powder is usually externally added to give the toner fluidity. However, conventional negatively charged silica fine powder has a large amount of charge, especially in low humidity conditions, and adding it externally has caused a problem of worsening environmental stability.

Until now, the conventional approach has been to suppress the water absorption of silica and stabilize the amount of triboelectric charge of the silica itself in order to obtain toners with good environmental stability. Such an example is
Unexamined Japanese Patent Publication No. 4 as a method for treating silica with silicone oil
There are Japanese Patent Publication No. 9-42354 and Japanese Patent Publication No. 16219/1989 Koji, which externally adds hydrophobic silica to toner. In addition, as a method for externally adding silica treated with a silane coupling agent to toner, Japanese Patent Application Laid-Open No. 56-1235
There are publications such as Publication No. 50. Thus, conventional developments have focused attention solely on treating agents and treatment methods for making silica hydrophobic.

The present inventors have confirmed that one of the causes of environmental instability of toner is environmental fluctuations in the amount of triboelectric charge of toner. The degree of environmental variation in the amount of triboelectric charge of toner varies depending on the type of toner carrier such as carrier or sleeve, but silica also has a considerable influence. Moreover, even if the above-mentioned polyester resin is used, the amount of triboelectric charge in toner without external addition of silica changes depending on the environment.
It is insufficient that the amount of triboelectric charge of silica itself does not change in the environment, and it is necessary to change it so as to offset the change in the toner to which silica is not externally added. Furthermore, silica, which has a high absolute value of triboelectric charge, is not preferred from the viewpoint of environmental stabilization of the toner. Here, silica with a high amount of triboelectric charge is iron powder (EF
V200/300 (manufactured by Nippon Iron Powder)) is 1-1501 μc/g or more when measured by the blow-off method at a ratio of silica to iron powder of 2:100.

Based on the above-mentioned new findings, the present inventors have developed silica that has low triboelectric charging properties and the amount of triboelectric charging decreases as the humidity decreases. As a result of extensive research, we found that if silica fine powder is treated with a silane coupling agent that has both positive and negative triboelectrification sites, and then further treated with silicone oil, it will have low triboelectrification and low humidity. The present invention was completed by discovering that silica with a reduced amount of triboelectric charge can be obtained.

As the silica fine powder of the present invention before being treated with the silane coupling agent, both dry process silica and wet process silica can be used. Silica is preferred.

The dry method mentioned here is a method for producing fine silica powder produced by vapor phase oxidation of a silicon halogen derivative. For example, this method utilizes a thermal decomposition oxidation reaction of silicon tetrachloride gas in oxygen and hydrogen, and the basic reaction formula is as follows.

5iCj'4+ 2 H2+ 02→SiO□+4 H
C1' Also, in this manufacturing process, for example, by using other metal halogen derivatives such as aluminum chloride or titanium chloride together with a silicon halogen derivative, it is also possible to obtain a composite fine powder of silica and other metal oxides. include.

On the other hand, various conventionally known methods can be applied to produce the silica fine powder used in the present invention by a wet method.

For example, the decomposition of sodium silicate with an acid can be expressed as a general reaction formula (the reaction formula is omitted below): NazO-XSiOz+I(Cj) +HzO→5iO
a'nH2O+Na j7Other methods include decomposition of sodium silicate with ammonia salts or alkali salts, generation of alkaline earth metal silicate from sodium silicate, decomposition with acid to produce silicic acid, sodium silicate solution There are methods such as converting it into silicic acid using an ion exchange resin, and using natural silicic acid or silicate.

The silica fine powder referred to herein can be any of anhydrous silicon dioxide (silica) and other silicates such as aluminum silicate, sodium silicate, potassium silicate, magnesium silicate, and zinc silicate.

Among the above silica fine powders, the specific surface area due to nitrogen adsorption measured by the BET method is 30 m"/g or more (especially 50 to 40 m"/g).
0m2/g) gives good results.

Examples of organic groups that can serve as positive triboelectric charging sites of the silane coupling agent include amino groups and nitrogen-containing heterocyclic groups. Examples of the nitrogen-containing heterocyclic group include an unsaturated heterocyclic group and a saturated heterocyclic group, and each of the known ones can be applied. Examples of compounds having an unsaturated heterocyclic group include the following.

Examples of compounds having a saturated heterocyclic group include the following.

(2) Further, nitrogen-containing salt compounds such as quaternary ammonium salts and pyridinium salts can also be exemplified. Further examples include phosphine and phosphonium salts. However, in consideration of ease of synthesis and cost, amino groups and nitrogen-containing heterocyclic groups are preferred.

Various organic groups can be exemplified as organic groups that can serve as negative triboelectric charging sites of the silane coupling agent. For example, ordinary silane coupling agents whose organic groups do not contain nitrogen or phosphorus are negatively triboelectrically charged. This is thought to be due to the 5i-C bond, but it is highly preferable to utilize this as a negative triboelectric charging site. However, in this case, the negative triboelectricity caused by the 5i-C bond decreases as the number of carbon atoms in the hydrocarbon directly bonded to Si increases, so in the case of the present invention, hydrocarbons with 3 or more carbon atoms cannot be used. .

Preferably, the number of carbon atoms is 2 or less.

Further, a negative triboelectric charging site can be positively provided in the silane coupling agent using an organic acid such as a carboxylic acid or a sulfonic acid, or an organo group having an acidic hydroxyl group such as a phenol.

Furthermore, halogen atoms, carbonyl groups, sulfonyl groups,
By using a cyano group or the like, a negative triboelectric charging site can be provided in the silane coupling agent.

The silane coupling agent according to the present invention can be synthesized by a conventionally known method. Basically, a hydrohalogenosilane or a hydroalkoxysilane and a compound having an alkene moiety into which a positive triboelectric charging site (if necessary, a negative triboelectric charging site) is introduced are reacted in the presence of a catalyst such as a platinum-containing compound. When using a 5i-C bond as a negative triboelectric charging site, it is not necessary to use a compound having an alkene moiety into which a negative triboelectric charging site is introduced, but in other cases, an alkene moiety into which a positive triboelectric charging site is introduced. It is necessary to use both a compound having a hydrohalogenosilane or a hydroalkoxysilane and a compound having an alkene moiety into which a negative triboelectrification moiety has been introduced. In this case, the order in which the compound having an alkene moiety into which a triboelectric charging site has been introduced may be applied may be positive or negative, or may be applied simultaneously. In addition, after obtaining two types of positive and negative silane coupling agents by reacting either a compound having an alkene moiety into which a positive or negative triboelectrification moiety is introduced with hydrohalogenosilane or hydroalkoxysilane, both positive and negative silane coupling agents are obtained. The silane coupling agent according to the present invention may be obtained by allowing the above to act.

Alternatively, a halogenoalkylalkoxysilane or a halogenoalkylhalogenosilane and the above compound having a positive triboelectric charging site (or a negative triboelectric charging site if necessary) may be allowed to act in the same way as described above. For example, in the case of diethylaminopropyltriethoxysilane, triethoxyhydrosilane and allyldiethylamine are reacted in the presence of a chloroplatinic acid catalyst, or chloropropyltriethoxysilane and diethylamine are reacted and then sodium methoxide is further reacted. It can be obtained by purification.

Representative examples of the silane coupling agent according to the present invention are shown below, but these are not intended to limit the present invention in any way.

1. Those using 5i-C bonds as negative triboelectric charging sites 2
, those using halogen, carbonyl, phenol, cyano group, etc. as a negative triboelectric charging site H3CNHC)12S
L(OCH3)33, using an organic carboxylic acid derivative as a negative triboelectric charging site Silica treated with the above-mentioned silane coupling agent improves the environmental stability of the toner and provides good fluidity and transferability. However, by further treating this silica with silicone oil, it is possible to further improve moisture resistance, fluidity, and transferability. That is, the silicone oil treatment can improve moisture resistance and improve the slipperiness of silica, thereby increasing the fluidity of the toner and further improving the transferability from the photosensitive drum.

The silicone oil used in the present invention is represented by the following formula for -M.

4. Products obtained by reacting a silane coupling agent having a negative triboelectric charging site with a silane coupling agent having a positive triboelectric charging site R: C+ to 3 alkyl group R': Alkyl, halogen-modified alkyl, phenyl, modified Silicone oil modified groups such as phenyl R"2C1-3 alkyl group or alkoxyl group Examples include dimethyl silicone oil, alkyl-modified silicone oil, α-methylstyrene-modified silicone oil, chlorphenyl silicone oil, fluorine-modified silicone oil, etc. In addition, the silicone oil preferably contains 2
Those having a viscosity of approximately 50 to 1000 centistokes at 5°C are used. Silicone oil with a molecular weight that is too low may generate volatile matter when subjected to heat treatment, and if the molecular weight is too high, the viscosity becomes too high, making treatment operations difficult.

Known techniques are used for this silicone oil treatment method, for example, silica fine powder treated with the above silane coupling agent and silicone oil may be directly mixed using a mixer such as a Henschel mixer, or silica It may be prepared by spraying silicone oil onto fine powder, or by dissolving or dispersing silicone oil in a suitable solvent, mixing it with fine silica powder, and then removing the solvent.

The degree of hydrophobicity of the silica fine powder according to the present invention is 90% or more (
(preferably 95% or more). If the degree of hydrophobicity is lower than this, high-quality images cannot be obtained due to moisture adsorption of the silica fine powder under high humidity.

The amount of silicone oil to be treated is only a small amount as the fine silica powder has been made hydrophobic in the previous stage, and is A/25±A/30.
(A: specific surface area of silica fine powder), more preferably A/
A range of 25±A/40 is desirable. What is the specific surface area of silica fine powder?

This is a value determined from N2 adsorption using the BET method.

The reason for limiting the amount of treatment is that if the amount of silicone oil treated is too small, the result will be the same as that of silane coupling agent treatment alone, making it impossible to achieve further improvement. In addition, if the amount of silicone oil treated is too large, the above-mentioned silica fine powder aggregates are likely to form, and even free silicone oil is formed, so when applied to a developer, it is necessary to improve the fluidity. There are disadvantages such as not being able to

The applied amount of the silica fine powder used in the present invention is 0.01 to 5%, preferably 0.05% based on the weight of the toner.
~2%. Further, the silicas used in the present invention can be used together or in combination with known silicas.

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 toner of the present invention, the volume average particle diameter of the toner is 6 to 6.
10 μm, 15 to 40 number % of toner particles have a particle size of 5 μm or less, and 0.1% of toner particles have a particle size of 12.7 to 16.0 μm.
The effect is more remarkable when toner particles of 6.35 to 1001 μm have a particle size distribution that satisfies the following formula: ~5.0% by volume, 161 or more and 1.0% by volume or less.

The toner having the above particle size distribution can faithfully reproduce the latent image formed on the photoreceptor, and is also excellent in reproducing halftone dots and minute dot latent images such as digital ones, especially in highlight areas. Provides images 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 main body of the copying machine or printer.

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

Conventionally, in toner, toner particles of 5 μm or less are difficult to control the amount of charge, impair the fluidity of the toner, are a component that scatters the toner and stains machines, and are a component that causes image fogging. It was considered necessary to actively reduce it. 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 having a non-magnetic toner and a carrier having a particle size distribution ranging from 0.5 gm to 30 #Lm, the surface potential on the photoreceptor is changed, and a large number of toner particles are easily developed. Developing potential: From contrast to halftone, to latent images of small minute dots in which only a few toner particles are developed, the latent image is developed by changing the latent image potential on the photoreceptor. When the toner particles were collected and the toner particle size distribution was measured, it was found that 8
It has been found that there are many toner particles of .mu.m or less (in particular, there are many toner particles 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 the latent image on the photoreceptor, they are faithful to the latent image and do not protrude from the latent image (an image with truly excellent reproducibility is produced). That's what you get.

In addition, toner particles with a diameter of 12°7 m to 16.0 μm are 5 m
Although non-magnetic toner particles with a particle size of 5 μm or less have the ability to faithfully reproduce the latent image of minute dots, they themselves have a considerable High cohesiveness (as a result, the fluidity of the toner may be impaired.

The present inventors attempted to further improve the fluidity by adding the above-mentioned silica fine powder for the purpose of improving the fluidity. It was confirmed that the conditions for satisfying . Therefore, the present inventors further investigated the particle size distribution of the toner, and found that the toner particles containing 15 to 40 number percent of toner particles with a particle size of 5 μm or less
．． It has been found that by containing toner particles of 7 to 16.04 m in an amount of 0.1 to 5.0% by volume, fluidity can be further improved and high image quality can be achieved. That is, 12.7 to 16
．． This is thought to be due to the fact that toner particles in the 0 μm range have suitably controlled fluidity compared to toner particles of 5 μm or less, and as a result, even when copying or printing is continued, resolution and gradation are maintained at high density. This provides sharp images with excellent tonality.

Furthermore, 6.35-10. l) Regarding the toner particles of Lm, their volume % (V), number % (N), and volume average particle diameter (
It is more preferable that the toner of the present invention satisfies the relationship Xdv 9≦≦14 (6≦dv≦10).

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 wind classification on a boat, the above value is large, which means that toner particles of about 5 μm that faithfully reproduce the minute dot latent image increase, and the above value is small. Reverse: This is understood to indicate that toner particles of about 5#Lm 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.

In addition, for toner particles with a particle size of 16 μm or more, 1
．． It is preferable to make it 0% by volume or less, and as little as possible.

The configuration of the present invention will be explained in more detail.

Toner particles with a particle size of 5 μm or less account for 14 to 15 of the total number of particles.
It is preferable that the number% is 20 to 35%, more preferably 20 to 35
The quantity percentage is good. When the number of toner particles with a particle size of 5 μm or less falls below 15%, there are few non-magnetic toner particles that are effective for high image quality, and especially as the toner is used for continuous copying or printing, the effective toner particle component decreases. decreases, and the balance of toner particle size distribution deteriorates.
Image quality gradually decreases. If it exceeds 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 causing the edges of the latent image to The difference in density with the inside becomes large, and the image tends to appear hollow.

In addition, particles in the range of 12.7 to 16.0 μm are 0.1 to 5
．． The content is preferably 0% by volume, preferably 0.2 to 3.
0% by volume is good. If 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, if it is less than 0.1% by volume, image density will decrease due to a decrease in fluidity.

In addition, 1.0% by volume of toner particles with a particle size of 16#Lm or more
It is preferable that the amount is less than The protruding presence of coarse toner particles of 16 μm or more on the thin layer surface of the particles makes the delicate state of contact between the photoreceptor and the transfer paper via the toner layer irregular, causing fluctuations in transfer conditions. , which is likely to cause a defective image to be transferred.Also, the volume average particle size of the toner is 6 to 6.
It is 10 .mu.m, preferably 7 to 9 .mu.m, and this value cannot be considered in isolation from each of 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 on the transfer paper is small (and the problem of low image density tends to occur. This is thought to be due to the same reason as the reason why the density inside the edge portion of the image decreases.

When the volume average particle diameter exceeds 10 μm, the resolution is not good, and although the copying process is good at the beginning, the image quality tends to deteriorate with continued use.

As described above, by using this toner, a copy image with high resolution, high definition, and high quality can be obtained, 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 force between the residual toner and the photoreceptor is reduced, which prevents poor cleaning and leakage from the cleaner. In addition, since it has sufficient fluidity, it is less likely to aggregate in the cleaner, and cleaning failures due to toner aggregation can be prevented.Furthermore, a sufficient amount of charge can be secured even under low humidity, so
No scattering or fogging occurs.

As the colorant, a wide range 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, benzidine yellow, etc. The amount is 12 parts by weight or less per 100 parts by weight of the binder resin so as to sensitively reflect the light transmittance of the OHP film.
Preferably it is 0.5 to 9 parts by weight.

A charge control agent may be added to the toner according to the present invention in order to stabilize charge characteristics. In this case, a colorless or light-colored charge control agent that does not affect the color tone of the toner is preferred. In the present invention, the present invention becomes more effective when a negatively charged developer is used, and the negative charge control agent in this case is, for example, a metal complex of alkyl-substituted salicylic acid (for example, di-
Examples include organometallic complexes such as chromium complexes or zinc complexes of 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. - Can be used in both component development method and two-component development method, but when used as a two-component developer, electrically insulating resin is used as the coating resin for the carrier core material, but toner material , is appropriately selected depending on the carrier core material. In the present invention, in order to improve the adhesion to the surface of the carrier core material, at least one monomer selected from acrylic acid (or its ester) monomer and methacrylic acid (or its ester) monomer is used. In particular, when polyester resin particles with a high negative chargeability are used as a toner material, it is preferable to further copolymerize the toner with a styrene monomer in order to stabilize the charge. The copolymerization weight ratio of the styrenic monomer is preferably 5 to 70% by weight.

The average molecular weight of the above-mentioned copolymer is determined by considering the uniformity of coating on the surface of the carrier core material and the coating strength.
000-35,000, preferably 17,000-24
, 000, weight average molecular weight is 25,000 to 100,0
00, preferably 49.000 to 55.000.

Examples of monomers for the coating resin of the carrier core material that can be used in the present invention include styrene monomers, polystyrene monomers, a-methylstyrene monomers, styrene-chlorostyrene monomers, and acrylic monomers such as There are acrylic acid ester monomers (methyl acrylate monomer, ethyl acrylate monomer, butyl acrylate monomer, octyl acrylate monomer, phenyl acrylate monomer, 2-ethylhexyl acrylate monomer), etc.
There are methacrylic acid ester monomers (methyl methacrylate monomer, ethyl methacrylate monomer, butyl methacrylate monomer, phenyl methacrylate monomer), etc.

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

Next, the contact charging process of the present invention applicable to the image forming method will be specifically explained.

The charging device according to the present invention is, for example, as shown in FIG. 3 is a photosensitive drum which is a charged body and rotates in the direction of the arrow. A charging roller 4 is a charging member that is brought into contact with the photosensitive drum 3 with a predetermined pressure. E
is a power supply unit that applies voltage to the charging roller 4 and supplies a predetermined voltage to the core metal 48 of the charging roller 4 . In FIG. 2, E indicates a DC voltage, but it may be a DC voltage superimposed with an AC voltage.

In the present invention, the conductive rubber layer 4b is provided on the metal core 48,
Furthermore, a surface layer 4c, which is a releasable film, was provided on the circumferential surface.

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, and a decrease in charging efficiency can be 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. 2 can also be used. Although a blade-shaped contact charging member is used here, a metal support member 4'a to which a voltage is also supplied is used.
By supporting the conductive rubber 4'b and providing a surface layer, which is a releasable film, on the portion in contact with the photoreceptor drum 3, the same effects as in the above example can be obtained.

In the above-mentioned example, a roller-shaped or blade-shaped charging member is used, but the present invention is not limited to this (although 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 the case where other materials are used, if even a small amount of the softener of the conductive rubber layer adheres to the photoreceptor, image fading becomes severe, so the effect of forming an insulating coating on the outside of the conductive rubber layer is greater. Furthermore, the charging device of the present invention can also be used for transfer.

Each of the measurement methods (1) to (4) related to the characteristic values of the toner used in the present invention will be described below.

(1) The particle size distribution measuring device is Coulter Counter TA-II type (
CX-1 and an interface (manufactured by Nikkaki) that outputs the number average distribution and volume average distribution using
A personal computer (manufactured by Canon) is connected, and a 1% NaCR aqueous solution is prepared using primary sodium chloride as the electrolyte.

As a measuring method, a surfactant as a dispersant, preferably an alkylbenzene sulfonate (0.1 to 5 mj), is added to the electrolytic aqueous solution at 100 to 150 mA', and 0.5 to 50 mg of a measurement sample is added.

The electrolyte in which the sample was suspended was dispersed for about 1 to 3 minutes using an ultrasonic disperser, and the particle size distribution of particles of 2 to 40 μm was measured using the Coulter Counter TA-n type using a 100 gm aperture. Measure the volume average distribution and obtain the number average distribution.

From the volume average particle size and number average distribution thus determined, the volume average particle size of 5.043 m or less in the number average distribution and 16.0 μm or more in the volume average distribution are obtained.

(2) Frictional charge measurement FIG. 3 is an explanatory diagram of the frictional charge amount measuring device.

First, the particles to be measured and iron powder particles EFV200/3
00 (manufactured by Powder Chick). In the case of the fluidity imparting agent, the mixing ratio is 2 parts by weight to 98 parts by weight of the magnetic particles.

Particles to be measured and magnetic particles are placed in a measurement environment and left for 12 hours or more, then placed in a polyethylene bottle, thoroughly mixed and stirred.

Next, a mixture of particles whose triboelectric charge is to be measured and magnetic particles is placed in a metal measurement container 12 with a conductive screen 13 of 500 mesh (the size can be changed as appropriate so that magnetic particles do not pass through) on the bottom. , a metal lid 14 is attached.

The weight of the entire measurement container 12 at this time is defined as the weight w+(g). Next, in the suction device 11 (at least the part in contact with the measurement container 12 is an insulator), suction is performed from the suction port 17, and the air volume control valve 16 is adjusted to adjust the pressure of the vacuum gauge 15 to 250 mmA.
Let it be q. In this state, suction is applied sufficiently (for about 2 minutes) to remove the toner. The potential of the electrometer 19 at this time is ■(
bolt). Here, 18 is a capacitor, which is a capacitance C (PF). Furthermore, the weight of the entire measurement container after suction is expressed as W2 (g). This amount of triboelectric charge T (pc
/g) is calculated as shown below.

(3) Hydrophobization degree measurement Put 100 mj+ of pure water and 1 g of sample in a sealed container,
Shake for 10 minutes using a shaker. After shaking, leave it to stand, and after the silica powder layer and water layer are separated, collect the water layer and
The transmittance is measured at a wavelength of m using blank pure water containing no silica fine powder as a reference, and the value of the transmittance is taken as the degree of hydrophobicity of the treated silica.

(4) Measurement of acid value and hydroxyl value Measurement of acid value is performed by measuring 2 to 10 g of sample over 200 to 300 m
Weigh into an R Erlenmeyer flask, methanol:toluene-3
0 near 0 mixed solvent 50m! Additionally, the resin is dissolved.

If the solubility seems poor, a small amount of acetone may be added. Pre-standardized N/10 using a mixed indicator of 0.1% bromothymol blue and phenol red.
The acid value is measured using potassium hydroxide and an alcoholic solution, and the acid value is determined from the consumption amount of the alcoholic potassium solution using the following formula (I).

Acid value = KOHCmR number) After measuring the saponification value of the acetylated product, it is calculated according to the following formula (n).

[Examples] Hereinafter, the present invention will be explained in detail with reference to Examples. Charging devices ■ to ■ and toners ■ to ■ were created.

Charging device ■: The configuration is shown in Figure 1, and the outer diameter of the charging roller 4 is 12 mm.
φ, the conductive rubber layer 4b was made of EPDM, and the surface layer 4C was made of nylon resin with a thickness of 10 μm. The hardness of the charging roller 4 was 54.5'' (ASKER-C).

Charging device (2): A charging roller having the same configuration as the charging device (2) but without the surface layer 4C was used. The rest is the same as the charging device (■).

<Resin production example> A modified polyester resin B was obtained by adding nolamine.

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

Table 1 The above compounds were mixed in a molar ratio of 1=1 and placed in a four-day round bottom flask equipped with a thermometer, Teflon coating, stirring blade, glass nitrogen inlet tube, condenser, and pressure reducing device. Ta. After nitrogen gas was introduced through the glass introduction tube to create an inert atmosphere inside the reaction vessel, the system internal temperature was maintained at -750 mmHzO by adjusting the opening degrees of the nitrogen gas introduction valve and the pressure reduction adjustment valve. Thereafter, the reactor was placed in a mantle heater, and the condensation reaction was carried out at 170° C. for 20 hours. The pressure at this time was also maintained at -750 mmLO.

This is called resin A.

After this, acetic acid is added to the system, and dieta toner is added to the system.
: After sufficiently premixing with a Henschel mixer,
The mixture was melt-kneaded twice or more in a three-roll mill, and after cooling, it was coarsely pulverized using a hammer mill to a particle size of about 1 to 2 mm.Then, it was pulverized in an air jet type pulverizer. The finely pulverized material was classified to obtain colorant-containing resin particles.

100 parts by weight of the above colorant-containing resin particles were treated with 20 parts by weight of the silane coupling agent shown in Compound Example (1-1) (temperature 150 ℃ 2 hours 2 hours), dimethyl silicone oil KF-96, 100cSt
(manufactured by Shin-Etsu Chemical Co., Ltd.) diluted with a solvent, and after drying, 0.5% of fine silica powder, which had been heated at about 250° C., was externally added to obtain a cyan toner. The degree of hydrophobicity of the treated silica fine powder was 99.9%. Further, the particle size distribution of this toner was as follows.

Toner ■: This was prepared in the same manner as Toner ■, except that Resin A was used as the binder resin.

Toner ◎: was used in the same manner as toner ■, with a volume average particle size of 7.2μ.
A red powder of m was obtained. 100 parts of the above colorant-containing resin particles and silica fine powder Aerosil 200 (manufactured by Aerosil ■)
After treating 100 parts by weight with 20 parts by weight of the silane coupling agent shown in Compound Example (1-2) (at a temperature of 150°C for 2 hours and 2 hours), dimethyl silicone oil KF-96 was added.
, 100 cSt (manufactured by Shin-Etsu Chemical Co., Ltd.) 10 parts and 0.5 part of fine silica powder treated in the same manner as toner A was added externally to prepare a toner. The degree of hydrophobicity of this treated silica fine powder is 99°9.
%Met.

Toner e: This was prepared in the same manner as Toner ◎ except that carbon black was used as the pigment.

Toner ■: This was prepared in the same manner as Toner ◎, except that negatively charged silica fine powder treated with dimethyldichlorosilane was used as the fluidity improver.

Except for Example 4 described later, 94 parts of Cu-Zn-Fe-based ferrite particles whose surface was coated with a styrene-acrylic acid-2-ethylhexyl methacrylate copolymer were mixed with 6 parts of these toners (1) to (2) and developed. It was used as a drug.

The charging device of a commercially available copying machine (CLC-500, manufactured by Canon) was modified to take the configuration shown in Figure 5, and the contact pressure to the photoreceptor was adjusted to 5.
0g/cm, development contrast is 23℃/65%
The applied voltage was adjusted to 290 V at 20° C./10%, 350 V at 30° C./80%, a developer using toner (2) was introduced, and an image was formed. As a result, the charging roller was hardly soiled after the durability test, and no filming occurred on the photoreceptor.

Further, even after the durability test, the decrease in charging efficiency was very small compared to before the durability test. During durability, high-quality images with sufficient image density of 1.40 to 1.55 and no fogging were obtained in each environment.

When a printing durability test similar to that of Example 1 was conducted using the above-mentioned charging process and developer, there was only a small decrease in charging efficiency, and no staining of the charging roller or filming of the photoreceptor occurred.

When a printing durability test similar to that of Example 1 was conducted using the above-mentioned charging process and developer, a high-quality image with sufficient image density was obtained. Further, no staining of the charging roller or filming of the photoreceptor occurred.

The charging roller was hardly dirty. Further, no filming occurred on the photoreceptor, and no decrease in charging efficiency was observed.

The charging device of a commercially available copying machine (CLC-500, manufactured by Canon) was modified to have the configuration shown in (2), and the developing device was modified to have the configuration shown in Figure 4 with the following conditions set to print images. I did it. That is, in FIG. 4, 22 is a sleeve (coating layer thickness: 13 μm) in which the surface of an aluminum cylinder is coated with a phenol resin in which 40 parts by weight of molybdenum disulfide is dispersed. 24 is a urethane sponge roller. The developer application blade 25 is connected to the sleeve 22
It is in contact with the top with a linear pressure of 80 g/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. 20℃/10%, 23℃/
As a result of a durability test of 6000 sheets under each environment of 60% and 30℃/80%, the image density was 1.40 to 1 in each environment.
．． 55, a stable and clear image without fogging was obtained.

Further, a printing durability test similar to that in Example 1 was conducted using the above-mentioned charging process and developer after the durability test. A significant decrease in charging efficiency can be seen after the durability test compared to before the durability test. °The charging roller was slightly dirty, and filming occurred on the photoreceptor. This is thought to be caused by the rubber softener in the charging roller.

A printing durability test similar to that in Example 1 was conducted using the above-mentioned charging process and developer. The charging roller was dirty, and filming also occurred on the photoreceptor. In addition, under low temperature and low humidity,
The image density decreased significantly compared to Example 1 as printing was carried out.

Comparative JLI Skin U As a result of carrying out the same printing durability test as in Example 1 using the above-described charging process and developer, the charging roller was contaminated, filming occurred on the photoreceptor, and image deterioration occurred.

[Effects of the Invention] According to the present invention, it is possible to maintain sufficient contact between the charging member and the object to be charged, to prevent the charging member and the object to be charged from sticking together, and to prevent dirt on the charging member and the object to be charged. This prevents filming and makes it possible to obtain high-resolution, high-definition images.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram schematically showing a charging roller according to the present invention. FIG. 2 is an explanatory diagram schematically showing a charging blade according to the present invention. FIG. 3 is a schematic diagram showing a triboelectric charge amount measuring device. FIG. 4 is a diagram illustrating the developing device used in Example 4. 3... Photosensitive drum 4a... Metal core 4b... Conductive rubber layer E... Power source 12... Measuring container 14... Lid 16... Air volume control valve 18... Capacitor 22...Sleeve 25...Blade 4.4'...Charging member 4'a...Metal support member 4'b...Conductive rubber 11: Suction device 13: Conductive screen 15: Vacuum gauge 17: Suction port 19: Electrometer 24: Sponge roller

Claims (4)

[Claims] (1) An insulating non-magnetic toner having at least non-magnetic colorant-containing resin particles and a flow improver, wherein the non-magnetic colorant-containing resin particles have a volume average particle diameter of 6 to 10 μm.
m, the main components are a diol component and a dicarboxylic acid component, at least a part of -COOH is substituted with a functional group containing N, and at least one of the fluidity improvers is The silica fine powder is treated with a silane coupling agent having a positive triboelectric charging site and a negative triboelectric charging site, and is further treated with silicone oil. magnetic toner. (2) The average volume diameter of the non-magnetic toner is 6 to 10 μm, and the number of toner particles with a particle size of 5 μm or less is 15 to 40
number%, 12.7 to 16.0 μm is contained in 0.1 to 5.0 volume%, 16 μm or more is contained in 1.0 volume% or less, and 6.3
The toner particles having a particle size of 5 to 10.1 μm satisfy 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 The non-magnetic toner according to claim 1, wherein the number % of toner particles having a particle diameter of .1 μm satisfies the following: @d@v: volume average particle diameter of all toner particles. (3) The amount of silicone oil treated is based on 100 parts by weight of the silica fine powder after treatment with the silane coupling agent.
A/25±A/30 parts by weight (A: specific surface area of silica fine powder), and a degree of hydrophobicity of 90% or more, the non-magnetic toner according to claim (1) or (2). . (4) A charging step in which a charging member to which a voltage is applied from the outside is brought into contact with the object to be charged, the charging object comprising a conductive rubber layer, and at least one area outside the conductive rubber layer. A charging step in which a charging member having a releasable film on a portion that contacts the charged object is brought into contact with the charged object and a voltage is applied from outside to charge the non-magnetic toner according to claim (1). 1. An image forming method comprising a developing step, a transfer step, and a cleaning step performed using a photoreceptor.