JPH0675431A - Blended toner - Google Patents

Abstract

PURPOSE:To provide a blended toner capable of preventing the occurrence of fog by a shortened rising time and capable of preventing the lowering of printing density at the time of long-time use by reducing the increase of electric charge rate after rising. CONSTITUTION:This blended toner contains an electric charge controlling agent, blended first and second toners which are triboelectrically charged by stirring with a carrier. The first toner is charged to the max. amt. of electric charges within 30sec after the beginning of stirring and the second toner is charged to the max. amt. of electric charges within 3-15min after the beginning of stirring.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blended toner used in an electrophotographic image forming apparatus such as a copying machine, a printer and a facsimile machine.

[0002]

2. Description of the Related Art In the electrophotographic method disclosed in, for example, US Pat. No. 2,297,691, the surface of a photoconductive insulator (photoreceptor) is uniformly charged by corona discharge or the like, and a light beam is applied to the surface. Printed matter by irradiating to form an electrostatic latent image, adhering fine powder called toner to the electrostatic latent image for development, transferring the toner image formed by the development to a recording medium such as paper, and fixing it. Is getting

The above-mentioned toner contains a colorant (pigment) such as carbon black, a charge control agent (dye), an additive, in a binder resin made of a natural polymer material or a synthetic polymer material,
It is one in which a surface treatment agent and the like are dispersed and finely pulverized to 1 to 30 μm.

The mixing ratio of these compositions is generally 80 to 95% by weight of binder resin, 5 to 15% by weight of pigment, 0 to 5% by weight of charge control agent, 0 to 2% by weight of additive, and 0 of surface treatment agent. ~ 1%.

The binder resin constituting the toner is required to be quickly melted in the process of fixing to a recording medium and exhibit good fixability, and is a low molecular weight low molecular weight polymer resin generally called an oligomer. Etc. are widely used.

Binder resins include those that are easily positively charged and those that are easily negatively charged. Typical examples of binder resins that are easily positively charged include ethyl cellulose, polyamide, and acrylic, which are negatively charged. Typical examples are polystyrene, polyethylene, polybutyl methacrylate, polyvinyl butyral and the like.

It is known that the pigment has a coloring function and the addition amount thereof affects the maximum charge amount of the toner. For example, as a pigment contained in a nigrosine dye added to a styrene resin, When the amount of carbon black added is varied, the maximum amount of charge decreases when the amount of addition is large, and the maximum amount of charge increases when the amount is small.

The maximum charge amount is the maximum or saturation value of the charge amount when a carrier and toner are combined and mounted in a developing device as a developer having a constant toner concentration and continuous stirring is performed. It refers to the amount of charge shown.

The charge control agent is blended to quickly charge the toner to a desired triboelectric charge amount by the friction of the toner with the carrier and maintain the charge, and the addition amount and the maximum charge amount. It is known that there is a certain relationship with. For example, it is known that if the addition amount of the nigrosine dye added to the styrene resin is varied, the maximum charge amount increases up to a certain amount, and if the amount exceeds the maximum amount, the maximum charge amount gradually decreases.

The material of the charge control agent depends on the desired polarity of the toner, and a positive polarity toner that is positively charged by friction uses a nigrosine dye, a quaternary ammonium salt, or the like, and a negative electrode that is negatively charged by friction. Azo dyes, salicylic acid complexes and the like are often used in the toners having a good sensibility.

The additives are added mainly to improve the melt viscosity of the binder resin and enhance the fixing property, and examples thereof include low molecular weight polypropylene and low molecular weight polyethylene.

The surface-treating agent is used for increasing the fluidity of the toner fine powder, and is effective for preventing toner aggregation and ground fogging, such as hydrophobic silica, titanium oxide, fatty acid metal edge fine powder, and alumina. Some of them are effective for stabilizing the triboelectrification of toners such as fatty acids, and it is known that addition of a surface treatment agent can improve the charging property. For example, when the surface of the positive polarity toner is surface-treated with hydrophobic silica, it is known that the charge amount decreases as the amount of hydrophobic silica treated increases.

After the toner is replenished in the developing device,
Carrier such as iron powder that is a ferromagnetic substance in the developing device
Is mixed with the carrier and is electrostatically attracted to the carrier by electrostatic charging, and is attracted to the magnet roll together with the carrier in the form of a magnetic brush. By rotating the magnet roll, it is carried out from the inside of the developing unit to the developing unit facing the photoconductor.
In the developing section, the charged toner is electrostatically attracted to the photoconductor to form a toner image.

[0014]

Toner is required to be charged to a constant charge amount as much as possible in order to maintain good print quality. That is, if the toner charge amount becomes excessive, the potential of the electrostatic latent image is filled with a small amount of toner, so that the amount of toner attached to the electrostatic latent image decreases and the print density decreases. , Scratching occurs. Further, if the charge amount of the toner is insufficient, the toner is separated and scattered from the carrier, and the toner adheres to the non-image portion as well, so that the entire recording medium is slightly soiled, that is, so-called background fog occurs.

The research on the relationship between the toner composition and the compounding ratio and the maximum charge amount of the toner has been conducted as described above, and some conclusions have been reached. However, sufficient research has not been conducted on the relationship between the maximum charge amount and background fogging or scraping.If it is attempted to prevent the occurrence of background fogging, it will not be possible to prevent the occurrence of scraping during long-term use, and conversely, long-term fogging will occur. In reality, it is impossible to prevent the occurrence of fog on the ground if it is attempted to prevent the occurrence of scrapes during time use.

Therefore, when a situation in which ground fog or scraping occurs is studied, ground fog occurs when the device is reused after being stopped for a long time.
It was found to occur when the device was used continuously for a long time.

Further, as a result of investigating the charge amount of the toner when the device is reused after being rested for a long time and the charge amount when the device is continuously used for a long time, the following has been found. That is, when the device is stopped for a long time, the electric charge held by the toner is gradually discharged into the atmosphere, and when it is reused, ground fog occurs in a low charged state until it reaches a predetermined charge amount. It has been found that the toner charged to a predetermined charge amount by continuous use for a long time is further agitated with the carrier and frictionally charged, and when the toner is excessively charged, scraping occurs.

From these facts, in order to prevent the occurrence of the background fog, the time required to quickly charge the toner to the predetermined charge amount from the start of stirring the toner is not directly related to the maximum charge amount of the toner, that is, It is effective to shorten the rise time, and in order to prevent the occurrence of blurring, the charge amount increases due to stirring after the toner is charged to a predetermined charge amount, regardless of the maximum charge amount of the toner. It has been found that it is effective to keep the value low.

However, as a result of further research, in order to shorten the rise time of the toner, it is necessary to increase the rate of increase of the charge per unit time of the toner after the stirring is started. The amount of charge continues to increase at a high rate of increase in charge even after reaching, and the amount of charge on the toner tends to become excessive within a short time, and continuous use of the device may easily cause scraping within a short time. Do you get it.

On the contrary, after reaching a predetermined charge amount,
In order to prevent excessive charging from occurring over a long period of time, it is necessary to reduce the rate of increase in charge of toner per unit time during stirring, which tends to lengthen the rise time, causing background fog at the time of rise. It turned out that it is likely to occur.

That is, in the case of a plain toner, the rise time is set to be short to prevent the occurrence of background fog, while the continuous use time is limited to prevent the occurrence of scrape, or the continuous use time is set to be long. While preventing scraping, it has no choice but to design selectively so that the standby time until the device becomes usable at the time of rising is prevented to prevent the occurrence of ground fog, and the rising time can be shortened. However, the problem is that a toner that can secure the stability of the charge amount after reaching the predetermined charge amount cannot be obtained.

Therefore, a toner having a short rise time,
When we tried a blended toner that was mixed with a toner with a long rise time, the toner with a short rise time increased the charge increase rate at the time of rising, and it started up in a shorter time than a toner with a long rise time. It has been found that the toner having a long time suppresses the charging increase rate to be small, and the occurrence of excessive charging can be prevented for a long time as compared with the toner having a short rise time.

The present invention has been made on the basis of the above-mentioned findings. The rise time can be shortened to prevent the occurrence of background fog, and the charge increase rate of the charge amount after reaching a predetermined charge amount can be improved. An object of the present invention is to provide a compounded toner which can be kept low and can prevent a decrease in print density (dullness) for a long time.

[0024]

The present invention provides a compounded toner containing a first toner and a second toner which contain a charge control agent and are triboelectrically charged by stirring with a carrier.
In order to achieve the above-mentioned object, the first toner charged to the maximum charge amount within 30 seconds after the start of stirring and 3 to 1 after the start of stirring
It is characterized in that it is mixed with a second toner which is charged to the maximum charge amount after 5 minutes.

[0025]

By blending the first toner that is charged to the maximum charge amount within 30 seconds after the start of stirring, the rate of increase in charge after the start of stirring is increased, the rise time is shortened, and the amount of charge increases from 3 to 3 after the start of stirring. By blending the second toner that is charged to the maximum charge amount after 15 minutes, the charge increase rate after rising is suppressed to a low level, and excessive charging of the blended toner is prevented for a long time.

In the present invention, the blending amounts of the first toner and the second toner are not particularly limited, and the required charging characteristics of the blended toner, the charging characteristics of the first toner and the charging characteristics of the second toner are taken into consideration. However, it is preferable that the blending amount of the second toner is about 2 to 3 times the blending amount of the first toner.

When the blending amount of the second toner is less than twice the blending amount of the first toner, the rise time is short, but the rate of increase in charge after the rise is high, and excessive charging occurs within a short time. This is not preferable because it may cause scraping.

If the blending amount of the second toner exceeds three times the blending amount of the first toner, the rate of increase in charge after the rise is low, but the rise time is long, and It is not preferable because ground fog is likely to occur at the time of starting up.

As a method of making the charging characteristics of the two types of toner different, the binder resin component of the toner, the addition amount of the charge control agent, the particle size of the charge control agent, the material of the charge control agent, and the charge control agent for the binder resin are used. It was found that there are methods such as different compatibility, dispersibility of the charge control agent, and addition amount of externally added silica.

However, the compounded toners obtained by mixing the components of the binder resin to prepare the first toner having a short rise time and the second toner having a high charge stability and mixing these components are the first and the second. A difference in melting temperature of the toner and viscoelasticity at the time of melting occurs between the two toners, and the fixing temperature range (minimum fixing temperature to maximum non-offset temperature) is narrowed, and it is difficult to obtain a blended toner suitable for practical use. I found out.

Therefore, in the present invention, the addition amount of the charge control agent, the particle size of the charge control agent, the material of the charge control agent,
A method of changing the charging characteristics of the toner by changing the charging characteristics of the toner depending on the compatibility of the charging control agent with the binder resin, the dispersibility of the charging control agent, the amount of silica added externally, and the like is recommended.

The addition amount of the charge control agent is generally about 0 to 5% by weight with respect to the total amount of the toner, but if the addition amount of the charge control agent is large, the rise time is shortened and the addition amount of the charge control agent is increased. The smaller the number, the longer the rise time.

Specifically, the content of the charge control agent in the first toner is 2 to 1 of the content of the charge control agent in the second toner.
It is preferably 0 times. When the content of the charge control agent in the first toner is less than twice the content of the charge control agent in the second toner, the rate of increase in charge after the rise is low, but the rise time is long. It is not preferable because ground fog is likely to occur at the time of starting up from an uncharged state.

If the content of the charge control agent in the first toner exceeds 10 times the content of the charge control agent in the second toner, the rise time is shortened, but the charge increase after the rise is increased. The rate is high and overcharged within a short time,
It is not preferable because scraping may occur.

The particle size of the charge control agent is generally set to 2 μm or less in order to ensure dispersibility above a certain level. If the particle size of the charge control agent is made smaller, the rise time becomes longer, and if it is made larger, the rise time becomes shorter. Become.

This is because when the particle size of the charge control agent is large, the dispersibility of the charge control agent is low and the charge control agent is unevenly distributed. Cleavage occurs at the location where the charge control agent is unevenly distributed during toner production to form toner particles. Therefore, it is considered that this is because the number of particles of the charge control agent distributed on the surface of the toner particles and in the vicinity thereof increases.

Specifically, the particle size of the charge control agent of the first toner is about 5/3 of the particle size of the charge control agent of the second toner.
(About 1.2 μm) or more is preferable. When the particle size of the charge control agent of the first toner is smaller than 5/3 of the particle size of the charge control agent of the second toner, the charging characteristic of the first toner approaches the charging characteristic of the second toner and rises. Although the rate of increase in the amount of electrostatic charge after that can be suppressed to a low level to prevent the occurrence of scratches over a long period of time, the rise time from the non-charged state becomes long and the background fog is likely to occur, which is not preferable.

The material of the charge control agent is not particularly limited, and even if it is a positive charge control agent that gives a positive charge to the toner by friction, it is a negative charge control agent that gives a negative charge to the toner by friction. Good. However, by changing the materials of the charge control agents having the same polarity, the charging characteristics of the toner can be changed.

When the material of the charge control agent is made different in order to make the charge characteristics of the toner different, the compatibility of the charge control agent with the binder resin and the case of using the charge control agent having the same compatibility with the binder resin are used. Can be considered separately from the case of using charge control agents of different materials.

As an example of using a charge control agent of a material having a similar compatibility with the binder resin, a nigrosine dye and a quaternary ammonium salt are used together as a charge control agent for the first toner, and The case where only the nigrosine dye is used as the charge control agent for the toner of No. 2 can be mentioned.

As an example of using a charge control agent of a material having a different compatibility with the binder resin, a nigrosine dye, which is a typical positive charge control agent, is used as the charge control agent of the first toner, and the second toner is used. As the charge control agent, there may be mentioned a case where a nigrosine dye having a higher compatibility than this is modified with an organic acid.

As a positive charge control agent having excellent compatibility with a nigrosine dye modified with an organic acid, a charge modified with maleic acid (Orient Chemical: product number N-
04), those modified with stearic acid (Orient Chemical: product number N-02, N-11), those modified with oleic acid (Orient Chemical: product number N).
-03, N-13) and the like, and a negative charge control agent that is an azo dye having excellent compatibility is also commercially available (Orient Chemical: Trade name S-34, Hodogaya Chemical: Trade name. Name T-95). In addition, an azo dye charge control agent having a slightly poor compatibility is also commercially available (Hodogaya Chemical Co., Ltd .: trade name TRH).

Silica is externally added in an amount of about 0 to 1% by weight or less as a surface treatment agent for increasing the fluidity of the toner fine powder, but by varying the external addition amount,
The charging characteristics of the toner can be different.

That is, when the amount of silica added externally is large, the rise time is short, and when it is small, the rise time is long. Specifically, the addition amount of silica externally added to the first toner is preferably twice or more the external addition amount of silica of the second toner.

When the amount of silica externally added to the first toner is less than twice the amount of silica externally added to the second toner, the rate of increase in charge after rising is suppressed to a low level and excessive charging occurs over a long period of time. However, the effect of shortening the rise time by externally adding silica to the first toner is reduced, the rise time becomes longer, and insufficient charging and ground fog are likely to occur, which is not preferable. .

The external addition amount of silica is usually 0 to 1% by weight.
However, it has been confirmed by experiments that the rise time is about 3 minutes at 0.2 wt% or less, and the rise time can be made within 30 seconds at 0.5 wt%. Although the lower limit of externally added silica that makes the rise time within 30 seconds has not been experimentally confirmed, this lower limit can be obtained by repeating the experiment by slightly changing the externally added amount of silica. The value is the lower limit of the amount of silica added to the first toner.

Although the upper limit of the amount of externally added silica, which gives rise time of 3 minutes or more, has not been experimentally confirmed yet, similarly, the upper limit of this amount can be obtained by repeating the experiment while slightly changing the amount of externally added silica. The value can be obtained, and this upper limit becomes the upper limit of the amount of silica added to the second toner.

[0048]

EXAMPLES Examples of the present invention and comparative examples will be specifically described below. To prepare the blended toners according to the examples of the present invention, the following toners A to M were prepared by a conventional method. [Toner A] Polyester resin (made by Kao: trade name Tuffton 2150) as a binder resin, oleic acid-modified nigrosine dye (charged by Orient Chemical: trade name Oil Black BY) as a charge control agent, oil furnace type carbon as a pigment Polypropylene wax as an additive, and the amount of the charge control agent added is 2% by weight of the total toner.

When the developer was combined with the vinylidene fluoride-coated magnetite carrier, the maximum charge amount was shown about 5 minutes after the start of stirring. The measurement of the charge amount was the same for each of the following toners, but was performed according to the magnet blow-off method. [Toner B] Polyester resin (made by Kao: trade name Tuffton 2150) as a binder resin, oleic acid-modified nigrosine dye (made by Orient Chemical: trade name Oil Black BY) as a charge control agent, oil furnace type carbon as a pigment Polypropylene wax as an additive, and the amount of the charge control agent added was 5% by weight of the total toner.

When the developer was combined with the vinylidene fluoride-coated magnetite carrier, the maximum charge amount was shown within 30 seconds from the start of stirring. [Toner C] Polyester resin as a binder resin (manufactured by Kao: trade name Tuffton 2150), azo dye as a charge control agent (manufactured by Hodogaya Chemical: product number T-9)
5), consisting of oil furnace type carbon as a pigment and polypropylene wax as an additive,
A charge control agent having a particle diameter of 0.8 μm is used.

When a styrene-acryl-coated magnetite carrier was used as a developer, stirring was started to about 3
The maximum charge amount was shown after a minute. [Toner D] A polyester resin as a binder resin (manufactured by Kao: trade name Tuffton 2150), an azo dye as a charge control agent (manufactured by Hodogaya Chemical: product number T-9)
5), consisting of oil furnace type carbon as a pigment and polypropylene wax as an additive,
A charge control agent having a particle diameter of 2.0 μm is used.

When a styrene-acryl-coated magnetite carrier is used as a developer, stirring is started.
The maximum charge was shown within seconds. [Toner E] Polyester resin (manufactured by Mitsubishi Rayon: product name Dial ER-501) as a binder resin,
Oleic acid-modified nigrosine dye as a charge control agent (Orient Chemical: trade name Oil Black BY) and quaternary ammonium salt (Orient Chemical: trade number P-5)
1), consisting of oil furnace type carbon as a pigment and polypropylene wax as an additive,
The amount of oleic acid-modified nigrosine dye added was 2.5% by weight of the total toner, and the amount of quaternary ammonium salt added was 0.5% by weight of the total toner.

When a combination with a vinylidene fluoride-coated magnetite carrier is used as a developer, stirring is started about 30 times.
The maximum charge was shown within seconds. [Toner F] Polyester resin as a binder resin (manufactured by Mitsubishi Rayon: product name Dial ER-501),
An oleic acid-modified nigrosine dye (trade name: Oil Black BY, manufactured by Orient Chemical Co., Ltd.) as a charge control agent, an oil furnace type carbon as a pigment, and a polypropylene wax as an additive. 3.0% by weight of the whole.

When a combination with a vinylidene fluoride-coated magnetite carrier is used as a developer, stirring is started to about 20.
The maximum charge amount was shown after a minute. [Toner G] Polyester resin (manufactured by Mitsubishi Rayon: product name Dial ER-501) as a binder resin,
Oleic acid modified nigrosine dye (manufactured by Orient Chemical: trade name Oil Black BY) and unmodified nigrosine dye (manufactured by Orient Chemical: trade name Bontron N-01) as charge control agents, oil furnace type carbon as pigment, addition A polypropylene wax as an agent, in which the amount of oleic acid-modified nigrosine dye added is 3.0% by weight of the total toner.

When combined with a vinylidene fluoride-coated magnetite carrier to prepare a developer, stirring is started for about 15 minutes.
The maximum charge amount was shown after a minute. [Toner H] Polyester resin (made by Mitsubishi Rayon: trade name Dial ER-501) as a binder resin,
An unmodified Nigrosine dye as a charge control agent (manufactured by Orient Chemical Co., Ltd .: trade name Bontron N-01), an oil furnace type carbon as a pigment, and a polypropylene wax as an additive. 3.0% by weight.

When the developer was combined with the vinylidene fluoride-coated magnetite carrier, the maximum charge amount was shown within 30 seconds from the start of stirring. [Toner I] Polyester resin as binder resin (manufactured by Kao: product name Tuffton 2150), azo dye as charge control agent (manufactured by Hodogaya Chemical: product number S-3)
4), consisting of oil furnace type carbon as a pigment, polypropylene wax as an additive, and hydrophobic silica (trade name: hydrophobic silica R972 manufactured by Nippon Aerosil Co., Ltd.) as an externally added surface treatment agent. The added amount is 0.1% by weight.

When a styrene-acryl-coated magnetite carrier was used as a developer, stirring was started to about 3
The maximum charge amount was shown after a minute. [Toner J] Polyester resin as a binder resin (manufactured by Kao: trade name Tuffton 2150), azo dye as a charge control agent (manufactured by Hodogaya Chemical: product number S-3)
4), consisting of oil furnace type carbon as a pigment, polypropylene wax as an additive, and hydrophobic silica (trade name: hydrophobic silica R972 manufactured by Nippon Aerosil Co., Ltd.) as an externally added surface treatment agent. The amount added is 0.5% by weight.

When a styrene-acryl-coated magnetite carrier was used as a developer, stirring was started.
The maximum charge was shown within seconds. [Toner K] Polyester resin (made by Kao: trade name Tuffton 2150) as a binder resin, oleic acid-modified nigrosine dye (charged by Orient Chemical: trade name Oil Black BY) as a charge control agent, oil furnace type carbon as a pigment Polypropylene wax as an additive, and the amount of the charge control agent added was 3% by weight of the total toner.

When the developer is combined with the vinylidene fluoride-coated magnetite carrier, stirring is started 4 to 5
The maximum charge amount was shown after a minute. [Toner L] Polyester resin as a binder resin (manufactured by Kao: trade name Tuffton 2150), azo dye as a charge control agent (manufactured by Hodogaya Chemical: product number T-9)
5), consisting of oil furnace type carbon as a pigment and polypropylene wax as an additive,
Using a charge control agent having a particle size of 1.2 μm.

When a styrene-acryl-coated magnetite carrier was used as a developer, stirring was started about 3
The maximum charge amount was shown after a minute. [Toner M] Polyester resin as a binder resin (manufactured by Kao: trade name Tuffton 2150), azo dye as a charge control agent (manufactured by Hodogaya Chemical: product number S-3)
4), consisting of oil furnace type carbon as a pigment, polypropylene wax as an additive, and hydrophobic silica (manufactured by Nippon Aerosil: trade name hydrophobic silica R972) as an externally added surface treatment agent. The amount of external addition is 0.2% by weight.

When a styrene-acryl-coated magnetite carrier was used as a developer, stirring was started about 3 times.
The maximum charge amount was shown after a minute. [Example 1] 70% by weight of Toner A and 30% by weight of Toner B were mixed and combined with a vinylidene fluoride-coated magnetite carrier as a printer (Fujitsu F
When a printing test was performed by mounting it on a 61144A1 type), good printing characteristics were maintained over 300,000 sheets. [Comparative Example 1] Toner A was combined with a vinylidene fluoride-coated magnetite carrier and mounted as a developer in a printer (F6677B1 manufactured by Fujitsu), and a printing test was conducted. As a result, good printing characteristics were maintained over 300,000 sheets. When the printer was stopped for one week and then reprinted, the charge amount of the developer was low during printing several tens to 200 sheets after the start of printing, and the background fog occurred. [Comparative Example 2] A toner B was combined with a vinylidene fluoride coated magnetite carrier and mounted as a developer in a printer (F6677B1 manufactured by Fujitsu), and a printing test was conducted. Two
When printing 10,000 sheets, the print density decreased. [Comparative Example 3] A toner A and a toner B were mixed in equal amounts and combined with a vinylidene fluoride-coated magnetite carrier to be used as a developer for a printer (F6677B1 manufactured by Fujitsu).
When it was mounted on a mold and subjected to a print test, the charge amount increased after the start of printing and the print density decreased after printing 80,000 sheets, although the print density was slower than in Comparative Example 2. [Comparative Example 4] Toner A (70% by weight) and Toner K (30% by weight) were mixed and combined with a vinylidene fluoride-coated magnetite carrier to provide a printer (Fujitsu F
61114A1 type) and a printing test was performed, good printing characteristics were maintained over 300,000 sheets, but when the printer was stopped for one week and then reprinted,
During the printing of several 10 to 200 sheets after the start of printing, the charge amount of the developer was low and the background fog occurred. [Example 2] A toner (75% by weight) and a toner D (25% by weight) were blended, combined with a styrene-acryl coated magnetite carrier, and mounted as a developer in a printer (F61144A1 manufactured by Fujitsu) to perform a printing test. Good printing characteristics were maintained over 200,000 sheets. [Example 3] A toner (75 wt%) and a toner D (25 wt%) were mixed, combined with a styrene-acryl coated magnetite carrier, and mounted as a developer in a printer (F61144A1 manufactured by Fujitsu) to perform a printing test. Good printing characteristics were maintained over 200,000 sheets. The rising characteristics of the toner L are similar to those of the toner C, and no difference between the toner L and the toner C was observed in terms of printing characteristics. [Comparative Example 5] Toner D was combined with a styrene-acryl-coated magnetite carrier and mounted as a developer in a printer (F61144A1 manufactured by Fujitsu), and a printing test was carried out. Was observed, and the print density decreased after printing about 100,000 sheets. Example 4 Toner E of 25% by weight and Toner F of 75% by weight were mixed and combined with a vinylidene fluoride-coated magnetite carrier to serve as a printer (Fujitsu F
When mounted on a 6774 type) and subjected to a print test, 50
Maintained good printing properties over 10,000 sheets. Example 5 Toner G in an amount of 75% by weight and Toner H in an amount of 25% by weight were combined and combined with a vinylidene fluoride-coated magnetite carrier to provide a printer (Fujitsu F
It was mounted on a 6774 type) and a printing test was performed.
Maintained good printing properties over 10,000 sheets. [Comparative Example 7] A toner G and a vinylidene fluoride coated magnetite carrier were combined and mounted as a developer on a printer (F6774 type manufactured by Fujitsu), and a printing test was conducted. 5 from the start
Background fogging occurred due to insufficient charging until about 0 sheets were printed. [Comparative Example 8] A toner H was combined with a vinylidene fluoride-coated magnetite carrier to form a developer, which was mounted in a printer (F6774 manufactured by Fujitsu) and subjected to a printing test. As a result, good printing characteristics were exhibited in a normal temperature and normal humidity environment. However, when printing in a low humidity environment, the amount of charge increased,
The print density decreased after about 200,000 sheets. [Example 6] A toner (75% by weight) and a toner J (25% by weight) were blended, combined with a styrene-acryl coated magnetite carrier, and mounted as a developer in a printer (F61144A1 manufactured by Fujitsu) to perform a printing test. Good printing characteristics were maintained over 200,000 sheets. [Example 7] Toner M was added in an amount of 75% by weight and Toner J was added in an amount of 25% by weight, and the toner was combined with a styrene-acryl coated magnetite carrier and mounted as a developer in a printer (F61144A1 manufactured by Fujitsu) to perform a printing test. Good printing characteristics were maintained over 200,000 sheets.

In each of the above examples, the amount of charge control agent added, the particle size of the charge control agent, the material of the charge control agent, the compatibility of the charge control agent with the binder resin, the dispersibility of the charge control agent, and the external addition. The charging characteristics of the first toner and the second toner are made different by making the addition amount of silica to be made different, but by making the components of the binder resin of the toner different, It is possible to make the charging characteristic different from that of the second toner.

[0063]

As described above, according to the present invention, by adding the first toner which is charged to the maximum charge amount within 30 seconds after the start of stirring, the charge increase rate after the start of stirring can be increased. Since the start-up time is shortened, it is possible to prevent the occurrence of background fog at the start of reprinting after the apparatus is stopped for a long time.

By blending the second toner which is charged to the maximum charge amount 3 to 15 minutes after the start of stirring, the charge increase rate after the start-up is suppressed to be low, and the blended toner may be overcharged for a long time. Therefore, it is possible to prevent the print density from being lowered during continuous use for a long time.

In the present invention, particularly when the compounding amount of the second toner is set to be 2 to 3 times the compounding amount of the first toner, the effect of enhancing the rising characteristics of the first toner and the effect of the second toner are obtained. The effect of suppressing the increase rate of charge after rising is more favorably achieved.

Front page continuation (72) Inventor Yoshio Fujiki 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa, Fujitsu Limited (72) Inventor Toshinari Shimizu 1015, Kamedotachu, Nakahara-ku, Kawasaki, Kanagawa (72) Invented Person Masaki Nagaoka 1015 Kamiodanaka, Nakahara-ku, Kawasaki, Kanagawa Prefecture, Fujitsu Limited (72) Inventor Yuko Kinashi 1015, Kamikodanaka, Nakahara-ku, Kawasaki, Kanagawa Prefecture Fujitsu Limited (72) Norihiro Suzuki, Nakahara, Kawasaki, Kanagawa 1015 Kamiodanaka, Ward within Fujitsu Limited (72) Inventor Masakazu Ide, 1015 Kamiodanaka, Nakahara Ward, Kawasaki City, Kanagawa Within Fujitsu Limited

Claims (8)

[Claims] 1. A compounded toner comprising a first toner and a second toner which contain a charge control agent and are triboelectrically charged by stirring with a carrier, wherein the toner is charged to a maximum charge amount within 30 seconds after the start of stirring. 1. A blended toner comprising the toner No. 1 and a second toner charged to a maximum charge amount 3 to 15 minutes after the start of stirring. 2. The blended toner according to claim 1, wherein the blending amount of the second toner is 2 to 3 times the blending amount of the first toner. 3. The content of the charge control agent of the first toner is
The blended toner according to claim 1, wherein the content of the charge control agent in the second toner is at least twice the content of the charge control agent in the second toner. 4. The particle size of the charge control agent of the first toner is
The blended toner according to claim 1, which has a particle size larger than the particle size of the charge control agent of the second toner. 5. The material of the charge control agent of the first toner and the material of the charge control agent of the second toner are made different.
Or the blended toner according to 2. 6. The charge control agent for the first toner comprises a nigrosine dye and a quaternary ammonium salt, and the charge control agent for the second toner comprises only a nigrosine dye.
The blended toner described in 1. 7. The charge control agent for the first toner comprises a nigrosine dye, and the charge control agent for the second toner has a higher compatibility with the binder resin than the nigrosine dye modified with an organic acid. The compounded toner according to claim 5, which is composed of one. 8. The silica is externally added to the first toner and the second toner, and the external addition amount of silica to the first toner is at least twice the external addition amount of silica of the second toner. Item 3. The blended toner according to Item 1 or 2.