JPH11119550A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably obtain a uniform and high-density image over a long term without making the device larger by setting the circumferential speed of a developer carrier to a specified value or more, making a 1st stirring and carrying means satisfy a specified condition and using specified toner. SOLUTION: A 1st toner housing chamber 12 is provided with the 1st stirring and carrying means 18 and a 2nd toner housing chamber 13 is provided with a 2nd stirring and carrying means 19 arranged to be opposed to the means 18 and carrying the toner to the chamber 12 while stirring the toner. Then, the circumferential speed (a) of the developer carrier 15 is >=250 mm/sec, the means 18 satisfies the condition shown by an expression; 0.007<=b/a<=0.030, and the toner whose weight average diameter is 4 to 9 μm, whose fluidity index is <=20 and whose condensation is 20 to 60% is used. In the expression, (a) means the circumferential speed of the developer carrier and (b) means the circumferential speed (mm/sec) of the 1st stirring means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for developing an electrostatic image, such as an electrophotographic method and an electrostatic printing method, with a toner to visualize the image.

[0002]

2. Description of the Related Art Conventionally, many electrophotographic methods have been known as described in U.S. Pat. No. 2,297,691, Japanese Patent Publication No. 42-23910, and Japanese Patent Publication No. 42-24748. However, generally, a photoconductive substance is used to form an electric latent image on the photoreceptor by various means, and then the latent image is developed using toner, and if necessary, transferred to paper or the like. After a toner image is transferred to a material, the image is fixed by heating, pressure, solvent vapor, or the like to obtain a copy.

Conventionally, for example, in a developing device for developing a latent image on a latent image carrier with a one-component magnetic toner, friction between magnetic toner particles and friction between a sleeve as a developer carrier and magnetic toner particles cause friction. The electrostatic image charge on the latent image carrier and a charge having a polarity opposite to the development reference potential are applied to the magnetic toner, and the magnetic toner is applied very thinly on the developing sleeve so that the latent image carrier and the developing sleeve face each other. The magnetic toner flies to and adheres to the electrostatic latent image on the surface of the photosensitive drum by the action of the magnetic field of the magnet immobilized in the developing sleeve in the developing area, and is developed. What is visualized as an image is known.

Conventionally, in a developing device using a one-component toner, the toner contained in a hopper chamber or the like is supplied from a developer supply section when the toner contained in the developer container is consumed by development. A system is employed in which the toner carrier is replenished with toner in an amount corresponding to the consumed toner amount.

In the case of performing such development, the original is not always constant, and an original having various image ratios is used. For this reason, for example, when reproducing an image having a very high density and including a solid black portion having a large area, the amount of toner consumption becomes large at a time, so that the toner supply is insufficient and an image having a uniform density is obtained. May not be obtained. Also, when a large number of originals having a low density or many white backgrounds are used, the supply of toner to the vicinity of the developer carrier tends to be excessive, so that the toner near the back of the sleeve is aggregated / compressed. So-called toner packing occurs. When the packing state is formed, not only is it difficult to supply the toner onto the sleeve, but also the load on the toner is increased, and the toner itself is deteriorated.

Further, the balance between the supply and demand of the toner is not only quantitative, but also the amount of triboelectric charge is given by the toner originally near the sleeve and the toner immediately after being supplied. Since a difference occurs in the charge amount, the fog appears on the image as ground fog / reversal fog.

In order to prevent ground fog, reversal fog, etc. due to insufficient charge or non-uniformity of the toner, a developing device which can sufficiently charge the toner when replenishing the toner has been developed. Various proposals have been made.

For example, Japanese Patent Application Laid-Open No. 5-72893 discloses a developer container which contains a developer and is divided into a stirring chamber and a developing chamber by a partition member. In the developing chambers, screw-type stirring / transporting means are arranged, respectively, and a type in which the diameter and the rotation direction of the stirring / transporting means are defined has been proposed. In such a developing device, although the developer is transported sufficiently by the two agitating and transporting means, it becomes difficult to obtain sufficient agitation enough to impart sufficient tribo to the toner (particularly in a high humidity environment). Bottom), ground fog, reverse fog, etc. may occur on the image.

In order to obtain an agitating effect for applying tribo to toner in an environment where tribo is hardly applied, such as a high humidity environment, an agitating and conveying means provided with fins between adjacent blade members is used. However, Japanese Patent Application Laid-Open
It has been proposed in Japanese Patent Laid-Open No. 1679 and JP-A-1-123327. By using this stirring and conveying means, the stirring efficiency of the toner is improved, but the conveying speed is reduced. Therefore, when continuously forming an image having a large toner consumption,
A toner density gradient occurs in the toner transport direction, and a difference occurs between the image density on the upstream side and the image density on the downstream side in the toner transport direction. As a result, a uniform image cannot be formed, which is not preferable.

In order to increase the conveying speed while maintaining high stirring efficiency, there are methods of increasing the rotation speed of the stirring and conveying means or increasing the outer diameter of the blade member. If it is increased, the impact force applied to the toner increases, so that the deterioration of the toner is accelerated, and it is difficult to obtain a stable image for a long period of time. In addition, if the outer diameter of the blade member is increased, the size of the apparatus itself is increased, which is not preferable.

As described in Japanese Patent Application Laid-Open No. Hei 4-100075, means for bringing a toner stirring / supplying member, which is an internal cavity, close to the developer carrying member is conceivable. When copying a large number of originals that consume a large amount of paper, it is necessary to greatly increase the number of revolutions of the supply member, which causes excessive stress on the toner, and causes a problem that the developing performance is reduced.

Further, it is expected that the proper values of the conveying speed and the outer diameter of the stirring and conveying means will change depending on the physical properties of the toner. For this reason, it is necessary to balance these two.

[0013]

SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus capable of stably obtaining a uniform and high-density image for a long time without increasing the size.

It is another object of the present invention to provide an image forming apparatus capable of obtaining good image quality all the time in a copying machine having a process speed ranging from a medium speed to a high speed.

Another object of the present invention is to provide an image forming apparatus capable of obtaining a clear image without fogging in any digital copying machine under any environment.

Still another object of the present invention is to maintain stable developing performance at all times without causing deterioration of the toner in the developing device in any copy mode regardless of continuous / intermittent. It is an object of the present invention to provide an image forming apparatus capable of performing the above.

[0017]

Specifically, the present invention provides:
An image forming apparatus having a latent image carrier for carrying an electrostatic latent image and a developing device, wherein the developing device includes a toner for developing an electrostatic latent image in a development area facing the latent image carrier. A developer carrying member for carrying the developer while carrying the toner, a first toner accommodating chamber accommodating the toner to be supplied to the developer carrying member, and supplying the toner to the first toner accommodating chamber. And a second toner storage chamber for
The toner storage chamber and the second toner storage chamber are in communication with each other, and the first toner storage chamber is provided with a first stirring and conveying means for conveying the toner while stirring the developer along the longitudinal direction of the developer carrier. In the second toner accommodating chamber, there is provided a second agitating / conveying means for conveying the toner to the first toner accommodating chamber while agitating the toner, the second agitating / conveying means being disposed opposite to the first agitating / conveying means. The peripheral speed (a) of the developer carrier is not less than 250 mm / sec, and the first stirring / transporting means is under the following conditions:

[0018]

[Outside 2] [Where a represents the peripheral speed of the developer carrying member, and b represents the peripheral speed (mm / sec) of the first stirring means. Is satisfied,
The present invention relates to an image forming apparatus, wherein the toner has a weight average diameter of 4 to 9 μm, a fluidity index of 20 or less, and a degree of compression (Co) of 20 to 60%.

[0019]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below.

In recent years, the demand for copying machines has been increasing more and more, and accordingly, the demands of users have become higher. Furthermore, digital copiers have rapidly become popular today, and in particular, demands for image quality are becoming higher.

In order to satisfy this demand, the industry has practiced improvement of toner stirring / conveying means in a developing unit or improvement of toner. However, especially in a system having a relatively high process speed, particularly at a medium speed to a high speed, it is extremely difficult to always maintain a stable developing property, and a copy having a satisfactory image quality for the user has not been obtained at present. .

The reason for this is, for example, the transportability and packing of the toner in the developing device. In other words, it is difficult for the methods devised so far to maintain both in an appropriate state under any environment.
That is, in a system with a configuration that emphasizes transportability, the toner forms a packing state between the developer carrier and the blade, and as a result, the toner coat on the developer carrier tends to be insufficient, Developability decreases. Further, if the agitation and transportability in the developing device is insufficient to improve the packing of the toner, the supply of the toner to the developer carrying member is insufficient, which also causes a decrease in the developability. Further, since the copying machine copies charts having various document ratios, it is more difficult to keep the state of the toner in the developing device constant.

On the other hand, with respect to toner, it is well known that the toner has been reduced in particle size / particle size in order to achieve "higher quality of copy images". If the toner particle size is reduced, it is expected that the toner transporting and packing properties in the developing device will become more severe, and it will be more difficult to keep the developing system constantly stable.

Therefore, there is a need for an image forming apparatus that can always obtain good developability in consideration of not only the configuration inside the developing device but also the physical properties of the toner.

The present invention has been made in view of the above matters. That is, the developing device has a toner storage chamber divided into two as shown in FIG. 2, and the toner is stirred toward the first toner storage chamber by the second stirring and conveying means in the second toner storage chamber. The toner is transported while being agitated by the first agitating and transporting means provided in the first toner storage chamber. The peripheral speed (a) of the developer carrier (sleeve) is 250 m
m / sec or more (preferably 300 to 800 mm /
sec), it is possible to satisfactorily cope with a process from medium speed to high speed.

In the present invention, one of the features is that when the peripheral speed of the first stirring and conveying means is b (mm / sec), b / a satisfies 0.007 to 0.03. . When b / a is smaller than 0.007, the supply of the toner to the developer carrying member is reduced, and a partially white missing image is likely to be formed when many originals having a high image ratio are copied. . If it is larger than 0.03, the supply of the toner becomes excessive, giving an extra stress to the toner, or forming the packing state of the toner on the back of the sleeve or the back of the blade to supply the toner to the sleeve. Is less likely to occur and, as a result, developability tends to decrease. Here, as the stirring and conveying means, a rod type, a crank type, a screw type, a fin type or the like can be used.

Further, in the image forming apparatus, when the peripheral speed of the second stirring and conveying means is c (mm / sec), c / mm
It is preferable that b is 1.0 to 2.0. When c / b is smaller than 1.0, the supply of toner from the second toner storage chamber to the first toner storage chamber is insufficient, and image defects are likely to occur partially. (Especially when a large number of charts with a large image ratio are copied.) When c / b is greater than 2.0, the amount of toner supplied to the first toner storage chamber becomes too large, and the first toner storage It is not preferable because the toner is damaged in the room or packing behind the blade or the like is apt to occur, resulting in a decrease in developability.

Next, the toner will be described. The toner used in the present invention has a weight average particle size of 4 to 9 μm. If the weight average particle diameter of the toner is less than 4 μm, fogging is likely to occur on a white background, which is not preferable. Also,
Although details will be described later, there is also a problem that toner packing (at the back of the blade or the like) in the developing device is likely to occur. Further, when the weight average diameter of the toner is larger than 9 μm, it is difficult to faithfully reproduce the latent image, especially when a digital latent image is obtained, which is not preferable.

Here, the average particle size and the particle size distribution of the toner can be measured by various methods. In the present invention, the measurement was performed using a Coulter counter.

As a measuring apparatus, a Coulter Counter TA-II type or Coulter Multisizer II (manufactured by Coulter Inc.) is used. As the electrolyte, about 1% NaCl aqueous solution is prepared using primary sodium chloride. For example, ISOTON-II (manufactured by Coulter Inc.) can be used. As a measuring method, the electrolytic aqueous solution 100 to 150
0.1 to 5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant to each ml, and 2 to 20 mg of a measurement sample is further added. The electrolyte in which the sample is suspended is subjected to a dispersion treatment for about 1 to 3 minutes with an ultrasonic disperser,
The measurement device measures the volume and number of the toner using a 100 μm aperture as the aperture, and calculates the volume distribution and the number distribution. Then, a weight-based weight average particle diameter (D4) (the median value of each channel is set as a representative value for each channel) obtained from the volume distribution according to the present invention is obtained.

Further, the toner has a fluidity index (G) of 2
0 or less, preferably 5 to 15 is good. When the fluidity index G is larger than 20, the stirring and transport of the toner in the developing device is reduced, and when a large number of originals having a high image ratio are copied, white dropout is likely to occur partially or the image density is reduced. Or drop.

The toner fluidity index was measured using a powder tester PT-D manufactured by Hosokawa Micron as described below. A 60 mesh sieve 21 and 100 mesh are placed on the powder tester shaking table 24 in FIG.
The sieve 22 and the 200-mesh sieve 23 were set, and 2.0 g of the toner was gently placed on the 60-mesh sieve 21 and vibrated for 15 seconds with a vibration of 0.5 mm in amplitude and 50 Hz in frequency. The measurement is performed in an environment of 23 ° C./60% RH, and the toner used in the measurement is one that has been sufficiently aged in this environment.

The weight of the toner on each sieve was measured, and the toner fluidity index G was calculated by the following equation.

G1 = (toner weight on 60 mesh sieve / 2.0) × 100 G2 = (toner weight on 100 mesh sieve / 2.
0) × (3/5) × 100 G3 = (toner weight on 200 mesh sieve / 2.
0) × (1/5) × 100 G = G1 + G2 + G3

Further, the toner has a compression degree (Co) of 20.
６０60% is one of the features. When the degree of compression of the toner is less than 20%, the developer carrier (sleeve)
The upper toner coat layer tends to be in a non-uniform state, causing problems such as a decrease in image uniformity. If the degree of compression exceeds 60%, the toner is likely to be packed near the back of the blade of the developing device, the toner supply to the sleeve is insufficient, partial image defects occur, and high image density Is likely to occur.

In general, the smaller the toner particle size, the smaller the degree of compression and the more the toner tapping, that is, the more the toner packing inside the developing device, depending on the shape and external additives attached to the surface of the toner. Become.

Here, in the present invention, the degree of compression of the toner is measured as follows.

In a state where the toner on the sieve falls naturally by vibration and fills the cylindrical container, the loose apparent specific gravity (AD) is obtained.

Further, in the same manner, the toner is dropped while tapping the cylindrical container to increase the filling rate, and the apparent specific gravity (PD) is determined. Then, a value obtained by substituting each measured value into the following equation is defined as a degree of compression (Co).

Compression degree (Co) = 100 (PD−AD) / PD (PD: apparent apparent specific gravity AD: loose apparent specific gravity)

Next, the binder resin will be described.

Examples of the binder resin of the toner that can be used in the present invention include vinyl resins, polyester resins, polyurethane resins, epoxy resins, and phenol resins. Of these, vinyl resins and polyester resins are particularly preferred. .

As the carboxylic acid-containing monomer that can be used in the vinyl resin, a half-ester monomer of dicarboxylic acid is particularly preferable. For example, monomethyl maleate, monoethyl maleate, monobutyl maleate, monooctyl maleate, monoallyl maleate,
Half esters of α, β-unsaturated dicarboxylic acids such as monophenyl maleate, monomethyl fumarate, monoethyl fumarate, monobutyl fumarate, monophenyl fumarate, etc .; monobutyl n-butenylsuccinate, monomethyl n-octenylsuccinate, Half-esters of alkenyl dicarboxylic acids such as monoethyl n-butenylmalonate, monomethyl n-dodecenylglutarate, monobutyl n-butenyladipate; monomethyl phthalate, monoethyl phthalate, monobutyl phthalate, etc. Aromatic dicarboxylic acid half-esters;

Further, examples of the comonomers other than the carboxylic acid-containing monomer for obtaining the vinyl resin usable in the present invention include the following.

For example, styrene, o-methylstyrene, m
-Methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-ethylstyrene,
2,4-dimethylstyrene, pn-butylstyrene,
Styrene such as p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene and derivatives thereof; ethylene, Ethylene unsaturated monoolefins such as propylene, butylene and isobutylene; unsaturated polyenes such as butadiene; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide, and vinyl fluoride; vinyl acetate, vinyl propionate, and benzoate Vinyl esters such as vinyl acrylate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate , Meta Phenyl acrylic acid, dimethylaminoethyl methacrylate, alpha-methylene aliphatic monocarboxylic acid esters such as diethylaminoethyl methacrylate;
Methyl acrylate, ethyl acrylate, acrylic acid n-
Butyl, isobutyl acrylate, propyl acrylate,
Acrylic esters such as n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate and phenyl acrylate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether Vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone; N-vinyl pyrrole, N-vinyl carbazole, N
N- such as vinylindole and N-vinylpyrrolidone
Vinyl compounds of vinyl compounds; vinyl naphthalenes; acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, and acrylamide; used alone or in combination of two or more.

Of these, a combination of monomers that results in a styrene copolymer or a styrene / acrylic copolymer is preferred.

As the crosslinking monomer, a monomer having two or more polymerizable double bonds is mainly used.

The vinyl polymer which can be used in the present invention needs to be a polymer cross-linked with a cross-linkable monomer as exemplified below in order to achieve the object of the present invention.

Aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; diacrylate compounds linked by an alkyl chain such as ethylene glycol diacrylate, 1,3-butylene glycol diacrylate and 1,4-butanediol Diacrylate,
1,5-pentanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, and those obtained by replacing the acrylate of the above compounds with methacrylate; diacrylate linked by an alkyl chain containing an ether bond Compounds, for example,
Diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol # 400 diacrylate, polyethylene glycol # 600 diacrylate, dipropylene glycol diacrylate, and acrylates of the above compounds replaced with methacrylates; Diacrylate compounds linked by a chain containing an aromatic group and an ether bond, for example, polyoxyethylene (2) -2,2-bis (4-hydroxyphenyl) propane diacrylate, polyoxyethylene (4) -2 ,
2-bis (4-hydroxyphenyl) propane diacrylate and those obtained by replacing acrylates of the above compounds with methacrylates; further, polyester-type diacrylate compounds, for example, trade name MANDA (Nippon Kayaku) Can be Examples of polyfunctional crosslinking agents include pentaerythritol triacrylate, trimethylolethane triacrylate, trimethylolpropane triacrylate, tetramethylol methanetetraacrylate,
Oligoester acrylates and those obtained by replacing the acrylates of the above compounds with methacrylates; triallyl cyanurate, triallyl trimellitate; and the like.

These cross-linking agents may be used in combination with other monomer components 10
It is preferable to use 0.01 to 5% by weight (preferably 0.03 to 3% by weight) with respect to 0% by weight.

Among these crosslinkable monomers, those which are preferably used in the toner resin from the viewpoint of fixability and anti-offset properties include an aromatic divinyl compound (particularly divinylbenzene), an aromatic group and an ether bond. And diacrylate compounds linked by a chain.

As the polyester resin, a polyester resin comprising a condensation polymer of a polybasic acid component and a polyhydric alcohol component is preferable.

The composition of the polyester resin that can be used in the present invention is as follows.

Examples of the dihydric alcohol component include ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol and 1,5-pentanediol. , 1,6-hexanediol, neopentyl glycol, 2-ethyl-1,3-
Hexanediol, hydrogenated bisphenol A, or (A)
Bisphenol represented by the formula and derivatives thereof;

[0055]

[Outside 3] (Wherein R is an ethylene or propylene group, x and y are each an integer of 0 or more, and the average value of x + y is 0 to 10.) Diols represented by the formula (B);

[0056]

[Outside 4] And other diols.

Examples of the divalent acid component include benzenedicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid and phthalic anhydride or anhydrides thereof, and lower alkyl esters;
Alkyl dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, azelaic acid or anhydrides thereof, lower alkyl esters; alkenyl succinic acids or alkyl succinic acids such as n-dodecenyl succinic acid, n-dodecyl succinic acid, or anhydrides of the acids And lower alkyl esters; unsaturated dicarboxylic acids such as fumaric acid, maleic acid, citraconic acid and itaconic acid, and anhydrides thereof; dicarboxylic acids such as lower alkyl esters; and derivatives thereof.

Further, a trivalent or higher valent alcohol component and a trivalent or higher valent acid component which also function as a crosslinking component can be used in combination.

The polyhydric alcohol component having a valency of 3 or more in the present invention includes sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane,
Examples thereof include polyhydric alcohols having a valency of 3 or more such as 1,3,5-trihydroxybenzene.

The trivalent or higher carboxylic acid component in the present invention includes trimellitic acid, pyromellitic acid,
1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid,
1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, tetra (methylenecarboxyl) methane, 1,2,7, 8-octanetetracarboxylic acid, empol trimer acid, and anhydrides and lower alkyl esters thereof,

[0061]

[Outside 5] (In the formula, X represents an alkylene group or alkenylene group having 5 to 30 carbon atoms having at least one side chain having 3 or more carbon atoms.)
And polycarboxylic acids such as anhydrides and lower alkyl esters thereof and derivatives thereof.

The alcohol component used in the present invention is 40 to 60 mol%, preferably 45 to 55 mol%.
%, 60 to 40 mol% as an acid component, preferably 5%
It is preferably from 5 to 45 mol%.

The content of the trivalent or higher polyvalent component is preferably 5 to 60 mol% of all components.

In the present invention, the alcohol component of the polyester resin is preferably a bisphenol derivative represented by the formula (A), and the acid component is phthalic acid, terephthalic acid, isophthalic acid or anhydride thereof; succinic acid , N-dodecenyl succinic acid or anhydride thereof, fumaric acid, maleic acid, dicarboxylic acids such as maleic anhydride,
Trimellitic acid or its anhydride tricarboxylic acids may be mentioned.

This is because the polyester resin obtained with these acids and alcohols exhibits sharp melting characteristics, has good fixability as a heat roller fixing toner, and has excellent offset resistance.

Further, the glass transition temperature of the polyester resin obtained here is 50 to 70 ° C., preferably 55 to 70 ° C.
5 ° C., and a number average molecular weight Mn of 1,500 to 10,000.
0 preferably 2,000 to 7,000, weight average molecular weight Mw 6,000 to 200,000, preferably 10,000.
It is preferably from 0 to 150,000.

In the toner used in the present invention, it is preferable that a charge control agent is blended (internally added) to the toner particles or mixed (externally added) with the toner particles. The charge control agent makes it possible to control the amount of charge optimally according to the development system. In particular, in the present invention, the balance between the particle size distribution and the charge can be further stabilized.

For example, as the positive charge control agent, a modified product of nigrosine and a fatty acid metal salt; a quaternary ammonium salt such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate and tetrabutylammonium tetrafluoroborate Diorganotin oxides such as dibutyltin oxide, dioctyltin oxide and dicyclohexyltin oxide; diorganotin borates such as dibutyltin borate, dioctyltin borate and dicyclohexyltin borate can be used alone or in combination of two or more. Among these, charge control agents such as nigrosine compounds and organic quaternary ammonium salts are particularly preferably used.

[0069]

[Outside 6] [Wherein, R ₁ represents H or CH ₃ , and R ₂ and R ₃ represent a substituted or unsubstituted alkyl group (preferably, C ₁ -C 3
₄ ) is shown. Or a copolymer with a polymerizable monomer such as styrene, acrylate or methacrylate as described above can be used as the positive charge control agent. In this case, these charge control agents also act as (all or part of) the binder resin.

As the negative charge control agent that can be used in the present invention, for example, organometallic compounds and chelate compounds are effective. Examples thereof include aluminum acetylacetonate, iron (II) acetylacetonate, and chromium 3,5-di-tert-butylsalicylate. Particularly, acetylacetone metal complex, monoazo metal complex, naphthoic acid or salicylic acid-based metal complex or Salts are preferable, and salicylic acid-based metal complexes, monoazo metal complexes, and salicylic acid-based metal salts are particularly preferable.

The above-mentioned charge control agent is preferably used in the form of fine particles. In this case, specifically, the number average particle diameter of the charge control agent is preferably 4 μm or less (more preferably 3 μm or less).

When the charge control agent is internally added to the toner, it is preferable to use 0.1 to 20 parts by weight (preferably 0.2 to 10 parts by weight) of such a charge control agent based on 100 parts by weight of the binder resin.

In the image forming apparatus of the present invention, when a magnetic toner is used as the toner, usable magnetic materials include iron oxides such as magnetite, maghemite, and ferrite, and iron oxides containing other metal oxides. Metals such as Fe, Co, Ni, or these metals and Al, Co, Cu, Pb, Mg, Ni, Sn,
Zn, Sb, Be, Bi, Cd, Ca, Mn, Se, T
Alloys with metals such as i, W, and V, and mixtures thereof, and the like.

Conventionally, as a magnetic material, triiron tetroxide (F
e ₃ O ₄ ), iron sesquioxide (γ-Fe ₂ O ₃ ), zinc iron oxide (ZnFe ₂ O ₄ ), yttrium iron oxide (Y ₃ Fe
₅ O ₁₂ ), cadmium iron oxide (CdFe ₂ O ₄ ), gadolinium iron oxide (Gd ₃ Fe ₅ -O ₁₂ ), copper iron oxide (C
uFe ₂ O ₄ ), lead iron oxide (PbFe ₁₂ —O ₁₉ ), nickel iron oxide (NiFe ₂ O ₄ ), iron neodymium oxide (Nd
Fe ₂ O ₃ ), barium iron oxide (BaFe ₁₂ O ₁₉ ), magnesium iron oxide (MgFe ₂ O ₄ ), iron manganese oxide (MnFe ₂ O ₄ ), lanthanum iron oxide (LaFeO)
₃ ), iron powder (Fe), cobalt powder (Co), nickel powder (Ni), etc. are known, but according to the present invention, the above-mentioned magnetic materials are selectively used alone or in combination of two or more. I do. Particularly preferred magnetic materials for the purposes of the present invention are fine powders of iron tetroxide or γ-iron sesquioxide. These ferromagnetic materials have an average particle size of about 0.1 to 2 μm and 795.8 kA.
/ M (10 k Oersted) applied have a coercive force (Hc) of 1.6 to 16 kA / m and a saturation magnetization (σs) of 5
0 to 200 Am ² / kg, residual magnetization (σr) 2 to 20 A
m ² / kg is preferred.

The magnetic substance 1 was added to 100 parts by weight of the binder resin.
It is preferable to use 0 to 200 parts by weight, preferably 20 to 150 parts by weight.

The colorant that can be used in the toner used in the image forming apparatus of the present invention includes any appropriate pigment or dye.

For example, pigments include carbon black, aniline black, acetylene black, naphthol yellow, hansa yellow, rhodamine lake, alizarin lake, bengara, phthalocyanine blue, and indanthrene blue. 0.1 to 100 parts by weight of resin
It is preferred to use up to 20 parts by weight, preferably 1 to 10 parts by weight of pigment. For the same purpose, a dye is further used. For example, there are azo dyes, anthraquinone dyes, xanthene dyes, and methine dyes, and 0.1 to 20 parts by weight, preferably 0.3 to 10 parts by weight, per 100 parts by weight of the resin.
It is preferred to use parts by weight of the dye.

In the present invention, one or more release agents may be contained in the toner, if necessary.

The following are examples of the release agent used for the toner. Aliphatic hydrocarbon-based waxes such as low-molecular-weight polyethylene, low-molecular-weight polypropylene, microcrystalline wax, and paraffin wax; and aliphatic hydrocarbon-based waxes such as oxidized polyethylene wax, or block copolymers thereof; Examples of the wax include waxes mainly containing a fatty acid ester such as wax, sasol wax and montanic acid ester wax, and those obtained by partially or entirely deoxidizing fatty acid esters such as deoxidized carnauba wax.
Furthermore, saturated straight-chain fatty acids such as palmitic acid, stearic acid, and montanic acid, unsaturated fatty acids such as brandinic acid, eleostearic acid, and vinaric acid, stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnaubivir alcohol, and seryl Alcohols, saturated alcohols such as merisyl alcohol, polyhydric alcohols such as sorbitol, fatty acid amides such as linoleic acid amide, oleic acid amide, lauric acid amide, methylenebisstearic acid amide, ethylenebiscapric acid amide, ethylenebis Saturated fatty acid bisamides such as lauric acid amide and hexamethylene bisstearic acid amide, ethylene bisoleic acid amide, hexamethylene bis oleic acid amide, N, N'-dioleyl adipamide, N, N -Unsaturated fatty acid amides such as dioleyl sebacamide, aromatic bisamides such as m-xylene bisstearic acid amide, N, N'-distearylisophthalic acid amide, calcium stearate, calcium laurate, zinc stearate , Fatty acid metal salts such as magnesium stearate (commonly referred to as metal soaps), and waxes obtained by grafting an aliphatic hydrocarbon wax with a vinyl monomer such as styrene or acrylic acid, Examples include partial esterified products of fatty acids such as behenic acid monoglyceride and polyhydric alcohols, and methyl ester compounds having a hydroxyl group obtained by hydrogenation of vegetable fats and oils.

The amount of the release agent that can be used in the toner used in the present invention is 0.1 to 20 per 100 parts by weight of the binder resin.
It is desirable that the amount be from 0.5 to 10 parts by weight.

These release agents are usually contained in the binder resin by dissolving the resin in a solvent, increasing the temperature of the resin solution, and adding and mixing while stirring, or by mixing at the time of kneading.

The developer used in the present invention preferably has a fluidizing agent added near the toner surface.

As the fluidizing agent, inorganic compound fine powder is preferable.

The fluidizing agent used in the present invention has a specific surface area by nitrogen adsorption measured by the BET method of 30 to 500 m ^2.
/ G (particularly 50 to 400 m ² / g) is preferred. 30m
If it is less than ² / g, the particle size becomes large, and it is difficult to uniformly disperse the particles on the toner surface. Also, 500m ²
If it is more than / g, it is not preferable because electrostatic flocculation of the fluidizing agents is likely to occur and "lumps" are likely to occur.

The material of the fine powder used in the present invention is preferably a Group 3 or Group 4 metal oxide such as silicic acid, alumina or titanium oxide.

[0086] In particular, dry silica fine powder produced by vapor phase oxidation of a silicon halide is preferred. During the production, it may be oxidized in the vapor phase together with other metal halides such as aluminum chloride and titanium chloride to obtain a composite fine powder of silica and metal oxide.

As the silica fine powder, both a so-called dry method produced by vapor phase oxidation of a silicon halide and a so-called fumed silica and a so-called wet silica produced from water glass can be used. However, dry silica having few silanol groups on the surface and inside and having no production residue is preferable.

Further, the silica fine powder is preferably subjected to a hydrophobic treatment. The hydrophobizing treatment is applied by chemically treating with an organic silicon compound or the like which reacts or physically adsorbs with the silica fine powder. A preferred method is to treat the dry silica fine powder produced by the vapor phase oxidation of the silicon halide compound with a silane coupling agent or simultaneously with the silane coupling agent and an organic silicon compound such as silicone oil. Is mentioned.

The silicone oil used for treating the silica fine powder is represented by the general formula

[0090]

[Outside 7] [Wherein, R represents an alkyl group having 1 to 3 carbon atoms, R 'represents a silicone oil-modified group such as alkyl, halogen-modified alkyl, phenyl and modified phenyl, and R "represents an alkyl group having 1 to 3 carbon atoms. Represents a group or an alkoxy group. ] Are preferred. Examples include dimethyl silicone oil, alkyl-modified silicone oil, α-methylstyrene-modified silicone oil, chlorophenyl silicone oil, and fluorine-modified silicone oil.

The above silicone oil preferably has a viscosity at 25 ° C. of 50 to 1000 mm ² / sec. 5
If it is less than 0 mm ² / sec, it is likely to volatilize partially due to the application of heat and to deteriorate the charging characteristics. 1000 mm ² /
When the time exceeds sec, handling tends to be difficult in terms of processing work. Known techniques can be used as a method of treating the silicone oil. For example, a method of mixing fine powder and silicone oil using a mixer, a method of spraying silicone oil into fine powder using a sprayer, and a method of dissolving silicone oil in a solvent and then mixing the fine powder are mentioned. Can be However, it is not limited to this.

Known substances can be used as the silicone varnish for treating the fine silica powder used in the present invention.

For example, KR-25 manufactured by Shin-Etsu Silicone Co., Ltd.
1, KP-112 and the like. It is not limited to these.

As the method of the silicone varnish treatment, the same known technique as the oil treatment can be used.

In the present invention, an amino-modified silicone oil having a structure represented by the following formula can be used as the silicone oil.

[0096]

[Outside 8] (Where R ₁ and R ₆ represent hydrogen, an alkyl group, an aryl group or an alkoxy group, R ₂ represents an alkylene group or a phenylene group, R ₃ represents a compound having a nitrogen-containing heterocyclic ring in its structure, R ₄ and R ₅ are hydrogen, an alkyl group,
Represents an aryl group. R ₂ may not be present. However, the above-mentioned alkyl group, aryl group, alkylene group and phenylene group may contain an amine, or may have a substituent such as halogen as long as the chargeability is not impaired. M is a number of 1 or more, and n and p are positive numbers including 0. Here, n + p is a positive number of 1 or more. The most preferred structure among the above structures is one in which the number of nitrogen atoms in the side chain containing a nitrogen atom is one or two.

Examples of the nitrogen-containing unsaturated heterocycle are shown below.

[0098]

[Outside 9]

Examples of the nitrogen-containing saturated heterocycle are shown below.

[0100]

[Outside 10]

The present invention is not limited to the above compound examples, but preferably has a 5-membered or 6-membered heterocyclic ring.

As the derivatives, a hydrocarbon group, a halogen group, an amino group, a vinyl group, a mercapto group,
Derivatives into which a methacryl group, a glycidoxy group, a ureido group, etc. are introduced are exemplified.

The amino-modified silicone oil used in the present invention preferably has a nitrogen atom equivalent of 10,000 or less, more preferably 300 to 6,000. The nitrogen atom equivalent here means the equivalent (g / eqi) per nitrogen atom.
In v), it is the value obtained by dividing the molecular weight by the number of nitrogen atoms per molecule. These may be used alone or in a mixture of two or more.

Examples of the silicone varnish used for obtaining the amino-modified silicone varnish for fine powder treatment used in the present invention include methyl silicone varnish and phenylmethyl silicone varnish.
Particularly, methyl silicone varnish is preferable.

Methyl silicone varnish is a polymer composed of T ³¹ units, D ³¹ units and M ³¹ units represented by the following structural formula, and is a three-dimensional polymer containing a large amount of T ³¹ units.

[0106]

[Outside 11]

Methyl silicone varnish or phenyl methyl silicone varnish is a substance having a chemical structure represented by, for example, the following structural formula.

[0108]

(R ³¹ represents a methyl group or a phenyl group.)

In the above silicone varnish, in particular, T ³¹
Units to provide good thermoset is an effective unit for a three-dimensional network structure, fine particles whose surface is treated with a silicone varnish containing such T ³¹ unit is tough and hard to the surface And has excellent impact resistance, moisture resistance, and mold release properties. T above
³¹ units are preferably contained in the silicone varnish at a ratio of 10 to 90 mol%, particularly 30 to 80 mol%.
When the proportion of the T ³¹ unit is too small, increased adhesiveness to soften might moisture resistance, durability, stability of triboelectric chargeability decreases, especially reduced cleaning property of the toner, the toner Scattering may occur, resulting in image unevenness, fogging, and the like, and may further decrease the durability of the fixing device.

[0110] the other hand, if the proportion of the T ³¹ unit is too large, skin covering layer formed on the surface of the inorganic fine particles is not uniform, the frictional chargeability of stability, durability may decrease.

Such a silicone varnish has a hydroxyl group at a terminal or a side chain of a molecular chain, and is cured by dehydration condensation of the hydroxyl group. Examples of the curing accelerator that can be used to accelerate this curing reaction include fatty acid salts such as zinc, lead, cobalt, and tin; amines such as triethanolamine and butylamine; and the like. Of these, amines can be particularly preferably used.

In order to make the above-mentioned silicone varnish into an amino-modified silicone varnish, the above-mentioned T ³¹ unit, D ³¹
Units, some of the methyl group or a phenyl group present in the M ³¹ unit may be replaced with a group having an amino group. Examples of the group having an amino group include those represented by the following structural formula. However, the present invention is not limited to these.

[0113]

[Outside 13]

As the method for treating the amino-modified silicone varnish, the same known technique as used for the oil treatment can be used.

The amount of the amino-modified silicone oil or the solid content of the amino-modified silicone varnish to be treated is 10 g of silica fine powder.
1 to 35 parts by weight, more preferably 2 to 35 parts by weight, per 0 parts by weight
30 parts by weight is good. Silica treated with silicone oil or silicone varnish exhibits an effect when used in an amount of 0.1 to 1.6 parts by weight with respect to 100 parts by weight of the toner, and particularly preferably 0.3 to 1.6 parts by weight when added. Has excellent stability. If less than 0.1 part by weight, the effect of addition is small,
If the amount exceeds 1.6 parts by weight, problems tend to occur during development and fixing, which is not preferable.

It is more preferred that the fine powder used in the present invention is first treated with a silane coupling agent and then treated with a silicone oil or silicone varnish.

In general, when only silicone oil treatment is used, a large amount of silicone oil is required to cover the surface of the fine powder, aggregates of the fine powder are easily formed during the treatment, and when applied to a developer, the fluidity of the developer becomes poor. Therefore, it is necessary to pay close attention to the silicone oil treatment process. In order to remove the agglomerates of the fine powder while maintaining good moisture resistance, it is better to treat the fine powder with a silane coupling agent and then treat it with silicone oil, so that the effect of treating the silicone oil can be sufficiently exhibited.

The silane coupling agent used in the present invention has a general formula R _m SiY _{n wherein} R represents an alkoxy group or a chlorine atom, m represents an integer of 1 to 3, Y represents an alkyl group, vinyl A hydrocarbon group containing a glycidoxy group or a methacryl group, and n represents an integer of 3 to 1. ] Are preferred. For example, typically dimethyldichlorosilane,
Trimethylchlorosilane, allyldimethylchlorosilane, hexamethyldisilazane, allylphenyldichlorosilane, benzyldimethylchlorosilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, divinylchlorosilane, dimethylvinyl Chlorosilane can be given.

The fine powder may be treated with a silane coupling agent by a dry process in which a vaporized silane coupling agent is reacted with a cloud of fine powder by stirring or the like, or
The treatment can be performed by a method such as a wet method in which fine powder is dispersed in a solvent and a silane coupling agent is dropped.

The silane coupling agent is used in an amount of 1 to 50 parts by weight, more preferably 5 to 4 parts by weight, per 100 parts by weight of the fine powder.
It is good to treat it as 0 parts by weight.

In the present invention, the treatment amount of the silicone oil or silicone varnish solid is preferably 1 to 35 parts by weight, more preferably 2 to 30 parts by weight, per 100 parts by weight of the fine powder. The reason for limiting the above treatment amount is that if the silicone oil treatment amount is too small, the result is the same as that of the silane coupling agent treatment alone, the moisture resistance does not improve, and the fine powder absorbs moisture under high humidity and high quality copy Images cannot be obtained.
If the silicone oil treatment amount is too large, the agglomerates of the above-mentioned fine powders are likely to be formed, and free silicone oil is formed, so that when applied to toner, the problem that the fluidity cannot be improved. Easy to occur.

As other additives, for example, lubricants such as Teflon, zinc stearate, and polyvinylidene fluoride are preferable, and polyvinylidene fluoride is particularly preferable. Alternatively, abrasives such as cerium oxide, strontium titanate, and strontium silicate, among which strontium titanate is preferred.
Other anti-caking agents, or white and black fine particles of opposite polarity can also be used in small amounts as developability improvers.

When the developer is a two-component developer, it is used by mixing with a carrier powder. In this case, the mixing ratio of the toner and the carrier powder is 0.1 to 5 as the toner concentration.
0% by weight, preferably 0.5 to 10% by weight, more preferably 3 to 5% by weight.

As the carrier, known carriers can be used. For example, powders having magnetism such as iron powder, ferrite powder, and nickel powder, and the surfaces thereof are made of fluorine resin, vinyl resin, silicone resin, or the like. Processed products can be mentioned.

To prepare a toner, a binder resin, a pigment or dye as a colorant, a magnetic material, a release agent, and if necessary, a charge control agent and other additives are mixed with a Henschel mixer, a ball mixer or the like. After thoroughly mixing with a machine, the mixture is melted using a hot kneader such as a heating roll, kneader, or extruder to disperse and disperse the release agent, pigment, dye, and magnetic material in the resin. After being cooled and solidified, pulverization and classification are performed to obtain a toner.

Further, if desired, desired additives are sufficiently mixed by a mixer such as a Henschel mixer to obtain a toner.

[0127]

Next, a preferred embodiment of the image forming apparatus according to the present invention will be described.

FIG. 2 is a structural diagram showing an example of the developing device used in the present invention. In an image forming apparatus such as an electrophotographic copying apparatus, as shown in FIG. 1, a developing device 11 for visualizing a latent electrostatic image formed on a latent image carrier (photosensitive drum) 10 as a toner image is provided. Used.

First, the developing device 11 shown in FIG. 2 will be described.

The developing device 11 has a first toner storage chamber (development chamber) 12 and a second toner storage chamber (hopper chamber) 13.
The developing chamber 12 and the hopper chamber 13 are partitioned by a partition wall member 14 so as to be able to communicate with each other. The developing chamber 12 and the hopper chamber 13 contain a toner 20 (in the case of a two-component developer, a mixture of a toner and a carrier).

In the developing chamber 12 of the developing device 11, the toner 2
A developer carrier (development sleeve) 16 that carries the toner image carrier 0 toward the electrostatic image carrier (photosensitive drum) 10 is accommodated therein. The developing sleeve 15 is disposed in the developing chamber 12 so that a part of the outer peripheral surface thereof projects outside, and the toner carried on the developing sleeve 15 is charged between the developing sleeve 15 and the photosensitive drum 10. A developing area for supplying the toner to the developing unit 10 is formed. Developing sleeve 15
Inside, a magnet 16 as a magnetic field generating means is fixed. The magnet 16 has a developing pole S1, a transport pole S2 for transporting toner, a cut pole N1, and a take-in pole N2.

A blade 17 for regulating the thickness of the toner carried on the developing sleeve 15 is disposed above the developing sleeve 15. The blade 17 is attached to the developing device.

The developing chamber 12 of the developing device 11
A stirring and conveying means 18 is provided, and a second
The stirring and conveying means 19 is installed in parallel or substantially parallel to the first stirring and conveying means 18. The developing sleeve 15, the first stirring and conveying means 18 and the second stirring and conveying means 1
9 rotates in the same direction, and the driving of rotation is synchronized.

When the developing device 11 is used, in the hopper chamber 13, while the replenished toner and the toner in the developing device are stirred by the stirring and conveying means 19, the partition member 14 is moved.
And a small amount is conveyed to the developing chamber 12 from the gap below the developing unit. In the developing chamber 12, the transported toner is sent in the longitudinal direction of the developing sleeve 15 by the first stirring and transporting means 18, and the toner 20 is carried on the S2 pole of the developing sleeve 15 by magnetic force during the transport. The toner 20 carried on the developing sleeve 15 is sent to the developing area after being regulated to a predetermined layer thickness by the blade 17. In the developing area, the toner transfers to a portion on the photosensitive drum 10 where a latent image is formed.

The toner that has passed through the developing area falls from the developing sleeve 15 to the developing chamber 12 near the point where the magnetic force becomes zero between the N2 pole and the S2 pole of the developing sleeve 15, and the toner that has dropped from the developing sleeve 15 is , First stirring and conveying means 1
8. The toner is returned to the hopper chamber 13 again by the first stirring and conveying means 18. Then, the first stirring / transporting means 18 stirs and mixes the toner remaining in the developing device, and supplies toner having sufficient triboelectricity at the magnetic pole S2 to the developing sleeve 15, and the magnetic poles N2 and S2
During this time, the toner is removed from the developing sleeve near the point where the magnetic force becomes zero, so that the toner in the developing chamber 12 can be reliably collected from the developing sleeve 15.

In the developing chamber 12, the toner is stirred and conveyed by the rotation of the first stirring and conveying means 18, and the toner having good fluidity is used, so that the toner is smoothly conveyed and uniform in the longitudinal direction of the developing sleeve 15. Can do it. Therefore, when continuously forming an image with a large toner consumption, there is no difference between the image density on the upstream side and the image density on the downstream side. In addition, in order to increase the transport speed while maintaining high stirring efficiency, it is not necessary to increase the outer diameter of the first stirring and transporting means 18 or increase the rotation speed, thereby preventing an increase in the size of the apparatus. Will be possible.

The remaining amount of toner in the developing device is
Is detected by a toner amount detector (not shown).
When the remaining amount of toner is low, replenishment toner is added to the hopper chamber 13. Supply toner 20 and hopper chamber 13
The toner 20 returned to the toner is sufficiently stirred by the second stirring and conveying means 19, so that sufficient tribo can be given to the replenished toner, and ground fog, reversal fog, and density reduction due to insufficient tribo are provided. Can be prevented beforehand.

The toner is sent to the developing chamber 12 again by the second stirring / conveying means 19, and is transferred from the hopper chamber 13 to the developing chamber 1
Then, the toner is circulated to the hopper chamber 13 through 2.

Next, a preferred specific example of the image forming apparatus of the present invention will be described with reference to FIG.

The surface of the OPC photosensitive drum, which is the latent image carrier 10, is negatively charged by using the primary charger 31, and a digital latent image is formed by image scanning by exposure with the laser beam 33 oscillated by the laser oscillator 32. The magnetic doctor blade 1 which is formed and controls the layer thickness of the developing sleeve 15 and the developing sleeve 15 enclosing the magnet 16
The reversal development is performed by the negatively chargeable one-component magnetic toner 20 in the developing device 11 provided with the toner 7. Alternatively, the surface of the drum is charged to a positive polarity using an amorphous silicon drum, an electrostatic charge image is formed, and reversal development is performed using the positive-polarity one-component magnetic toner 20.

Here, as the magnetic doctor blade 17, for example, an iron doctor blade is used as the developing sleeve 15.
(The gap is 50 to 500 μm), and is disposed opposite to one magnetic pole position (the N1 pole in FIG. 1) of the multi-pole permanent magnet, so that the thickness of the toner layer is reduced (30 to 300 μm).
m) and uniformly regulate the latent image carrier 1 in the developing section.
A toner layer thinner than the distance between 0 and the developing sleeve 15 is formed in a non-contact manner.

A bias applying means 3 is applied to the developing sleeve 15.
4, an alternating bias, a pulse bias and / or a DC bias are applied. When the transfer paper (not shown) is conveyed and reaches the transfer section, the toner image on the surface of the photosensitive drum is charged by the electrostatic transfer means 35 from the back surface of the transfer paper (the surface opposite to the photosensitive drum side). It is electrostatically transferred onto transfer paper. The transfer paper separated from the photosensitive drum 10 is
The toner image is transferred by the transfer belt 36 and fixed on the transfer paper by the heat and pressure fixing device 37.

The toner remaining on the photosensitive drum 10 after the transfer step is removed by a cleaner 39 having a cleaning blade 38. Photosensitive drum 10 after cleaning
Is removed by the erase exposure 40, and the process starting from the charging process by the primary charger 31 is repeated again.

An AC bias or a pulse bias may be applied to the developing sleeve 15 from the bias applying means. This AC bias has a frequency of 200-4000.
Hz and Vpp are preferably 500-3000V.

At the time of transfer of the toner particles in the developing portion, the electrostatic force of the surface of the photosensitive drum 10 holding the electrostatic image and the action of the bias or the pulse bias cause the toner particles to transfer.
The toner particles transfer to the electrostatic image side.

All parts in the following formulations are parts by weight unless otherwise specified.

Resin Production Example 1 Styrene 71 parts n-butyl acrylate 18 parts monobutyl maleate 10 parts 2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane 1 part

From the above materials, a styrene copolymer A was obtained by a suspension polymerization method.

Styrene 77 parts N-butyl acrylate 18 parts Monobutyl maleate 5 parts Di-t-butyl peroxide 2 parts

From the above materials, a styrene copolymer B was obtained by a solution polymerization method using xylene as a solvent, and the styrene copolymer A and the styrene copolymer B were mixed in a 30:70 weight ratio to form a styrene copolymer. A resin 1 was obtained.

The styrene resin 1 had Mn = 7400,
Mw = 288000, Tg = 60 ° C.

Resin Preparation Example 2 80 parts of styrene 20 parts of n-butyl acrylate 0.2 parts of divinylbenzene

From the above materials, a styrene polymer C was obtained by a suspension polymerization method.

Styrene 82 parts N-butyl acrylate 18 parts Di-t-butyl peroxide 2 parts

From the above materials, a styrene copolymer D was obtained by a solution polymerization method using xylene as a solvent, and the styrene copolymer C and the polymer D were mixed in a solution at a weight ratio of 28:72.
Styrene resin 2 was obtained.

This styrenic resin 2 has Mn = 680.
0, Mw = 225000, Tg = 59 ° C.

Resin Production Example 3 bisphenol A propylene oxide adduct 75 parts bisphenol A ethylene oxide adduct 50 parts terephthalic acid 25 parts succinic acid 20 parts 1,2,4-benzenetricarboxylic anhydride 25 parts

The above materials were placed in a 5 liter four-necked flask, equipped with a reflux condenser, a water separator, a nitrogen gas inlet tube, a thermometer and a stirrer. The condensation polymerization reaction was carried out at 230 ° C. while introducing nitrogen gas into the flask. Was carried out to obtain a polyester resin 3.

Mn of the selected polyester resin 3 is 60
00, Mw was 36,000, Tg was 61 ° C., acid value was 18, and hydroxyl value was 25.

Production Example 4 Resin 18 mol% terephthalic acid 23 mol% n-dodecenyl succinic acid 23 mol% trimellitic anhydride 8 mol% Bisphenol A propylene oxide adduct 51 mol%

The above compound was subjected to a polycondensation reaction in the same manner as in Production Example 3 of the above resin to obtain Mn = 550.
A polyester resin having 0, Mw = 47000, and Tg = 59 ° C. was obtained.

Toner Production Example 1 Styrene resin 1 (binder resin) 100 parts Magnetite (magnetic substance) 90 parts Monoazo iron complex (negative charge control agent) 2 parts Low molecular weight ethylene-propylene copolymer (release agent) 4 copies

After premixing the above materials with a Henschel mixer, melt kneading was carried out by a twin screw kneading extruder set at 130 ° C. After cooling the kneaded material, it is crushed by a cutter mill, the crushed material is crushed using a fine crusher using a jet stream, and further classified using an air classifier,
A toner was obtained.

To 100 parts of the toner, silica fine powder (BET30) treated with dimethyl silicone oil was used.
0 m ² / g) and 1.2 parts of strontium titanate.
5 parts were externally added and mixed with a Henschel mixer to obtain Toner 1.

The obtained negatively charged magnetic toner 1 had a weight average particle size of 6.7 μm (measurement was performed using Coulter Multisizer II), a fluidity index of 7, and a compressibility of 41.

Toner Production Example 2 Styrene resin 2 100 parts Magnetite 85 parts Tetrabutylammonium tetrafluoroborate (positive charge control agent) 3 parts Low molecular weight ethylene-propylene copolymer 4 parts

A toner was obtained in the same manner as in Production Example 1 of the toner except that the above-mentioned raw materials were used. 10 of this toner
0.8 parts of silica fine powder (BET 100 m ² / g) treated with amino-modified silicone oil and 0.5 parts of strontium titanate are added to 0 parts, and externally added and mixed with a Henschel mixer to obtain a positive charge. Magnetic toner 2
I got

The weight average particle diameter of the obtained toner 2 is 8.0.
μm, the fluidity index was 18, and the degree of compression was 27.

Toner Production Example 3 A toner was obtained in the same manner as in Toner Production Example 1, except that Resin 3 was used instead of Resin 1. Further, 100 parts of the toner was subjected to hexamethyldisilazane treatment with silica fine powder (BET30).
0 m ² / g) and 3.0 parts of strontium titanate were externally added and mixed with a Henschel mixer.
Toner 3 was obtained.

The obtained toner 3 has a weight average particle size of 7.
5 μm, fluidity index was 10, and compressibility was 33.

Production Example 4 Toner 100 parts polyester resin 4 (binder resin) 100 parts carbon black (colorant) 5 parts monoazo iron complex (negative charge controlling agent) 2 parts Sasol wax (release agent) 5 parts

A toner was obtained from the above materials in the same manner as in Production Example 1 of the toner. To 100 parts of the obtained toner, 1.5 parts of titanium oxide (BET 80 m ² / g) treated with dimethylsilane and dimethylsilicone oil was added, and externally added using a Henschel mixer to obtain a negatively charged non-charged toner. Magnetic toner 4 was obtained.

The toner 4 had a weight average particle size of 8.0 μm.
The fluidity index was 11, and the degree of compression was 25.

Examples 1 and 2 In FIG. 1, the toner 1 was put in the developing device 11 and the evaluation was performed. However, as for the photosensitive drum 10, an organic photosensitive (OPC) drum was used, and after performing negative corona charging, reversal development was performed in which a latent image was formed with a laser.

The developing sleeve 15 and the agitating / conveying devices 18 and 19 are both of a crank type, and their peripheral speeds are shown in Table 1. The image evaluation was performed under a low humidity environment (23 ° C./5% RH).

As a result, both at the initial stage and after 60,000 consecutive sheets,
Good results were obtained in image density, fog, image quality, and density gradation. The toner tribo on the sleeve was stable all the time. Table 2 shows the evaluation results.

Examples 3 and 4 In FIG. 1, the toner 2 was put in the developing device 11 and the evaluation was performed. However, as for the photosensitive drum 10, after performing positive corona charging using an amorphous silicon drum, reversal development was performed in which a latent image was formed with a laser.

The peripheral speeds of the sleeve and the agitating / conveying device are as shown in Table 1.

Regarding the method of image evaluation, the same method as in Example 1 was used, and good results were obtained both at the initial stage and after the endurance. Table 2 shows the evaluation results.

Examples 5 and 6 In FIG. 1, the toner 3 was put in the developing device 11 and evaluated. However, for the photosensitive drum 10, an amorphous silicon drum was used and positive corona charging was performed. For the formation of the latent image, regular development for forming an analog latent image was performed without using a laser.

Table 1 shows the peripheral speeds of the sleeve and the stirring and conveying device.

Further, as for the method of image evaluation, the same method as in Example 1 was used, and good results were obtained. Table 2 shows the evaluation results.

Examples 7 and 8 In FIG. 1, the toner 2 was put in the developing device 11 and the evaluation was performed. However, for the photosensitive drum 10, an organic photosensitive (OPC) drum was used, and negative corona charging was performed. For the formation of the latent image, regular development for forming an analog latent image was performed without using a laser beam.

Table 1 shows the peripheral speeds of the sleeve and the stirring and conveying device. As the first stirring and conveying means, a fin type was used, and the second stirring and conveying device was provided with "stirring tongue".
Changed to a crank type.

With respect to the image evaluation method other than the above, the same method as in Example 1 was used, and the results were good as shown in Table 2.

Examples 9 and 10 In FIG. 1, the toner 4 was put in the developing device 11 and the evaluation was performed. However, in the ninth embodiment, the developing device 11
Was applied to a non-magnetic one-component developing system.
Used a ferrite carrier whose surface was coated with a fluororesin, and changed to one that could be applied to a non-magnetic two-component developing system.

In Example 10, the toner concentration was 8%
And the toner was replenished only, and the carrier was not replaced.

[0188] The peripheral speeds of the sleeve and the stirring and conveying device are as shown in Table 1.

Other image evaluation methods were carried out in the same manner as in Example 1, and good results were obtained as shown in Table 2.

Comparative Toner Production Examples Toner Production Examples 1 to 3 were obtained by changing the conditions of pulverization and classification in Toner Production Example 1.

In Preparation Example 2 for toner, 0.5 part of silica fine powder treated with dimethyl silicone oil and 2.5 parts of strontium titanate were added to 100 parts of the toner, and the mixture was externally added and mixed. Thus, Comparative Toner 4 was obtained. Table 1 shows the physical properties.

Comparative Examples 1 to 3 In Example 1, comparative toner 1, comparative toner 2,
Image evaluation was performed using the same apparatus as in Example 1 except that Comparative Toner 3 was used. As a result, some troubles occurred as shown in Table 2.

Comparative Example 4 Evaluation was made in the same manner as in Example 3 except that Comparative Toner 4 was used. Comparative toner 4
Had a large fluidity index of 35. As shown in Table 2, as a result of the evaluation, a problem occurred due to the poor fluidity of the toner.

Comparative Examples 5 to 7 In the same manner as in Example 1, except that the peripheral speeds of the sleeve of the developing device 11 and the stirring and conveying means 18 and 19 were changed as described in Table 1. An image evaluation was performed. However, since the values deviated from the values specified in the present invention, the accompanying problems occurred as shown in Table 2.

Here, the evaluation criteria listed in Table 2 will be described.

Fog A (excellent): no fog is visually observed. B (good): no fog is observed unless gazing. C (acceptable): fog is present but no practical problem. D (bad): fog is not observed. stand out

Image quality A (excellent): a clear image with no scattering even when viewed with a loupe B (good): a clear image as seen with the naked eye C (acceptable): slight scattering is observed but practically OK Level D (Bad): Character blur is noticeable besides splatter

Density gradation A (excellent): An image with good reproducibility from a white background to a black background including a halftone B (good): A degree at which a slight roughness is observed in a highlight portion C (good): half Although there is roughness in the tone part, there is no practical problem. D (bad): There is also roughness in the solid part, and the level cannot be used.

Toner circulation in the developing device: Opening the lid of the developing device and visually assessing A (excellent): No toner packing on the back of the blade, good toner coating on sleeve B (good): Slight blade Level C (poor): no toner packing in the back of the toner or the amount of toner in the first storage chamber, but there is no problem in use. , The toner coat on the sleeve becomes non-uniform.

[0200]

[Table 1]

[0201]

[Table 2]

[0202]

According to the image forming apparatus of the present invention, the peripheral speed of each of the stirring and conveying means and the peripheral speed of the developing sleeve in the developing device divided into two chambers are defined, and the toner used in the developing system is further defined. By defining the physical property values of the above, a good image can be obtained from the initial period to the long term without increasing the size.

Further, even in the case of adaptation to a digital system, a high-density and high-quality copy image can be obtained throughout regardless of the copying environment.

Further, even when copying is performed for a long period of time, since toner deterioration does not occur, it is possible to cope with a wide range of process speeds from a medium speed to a high speed machine, and it is possible to always maintain stable developability.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing a specific example of an image forming apparatus of the present invention.

FIG. 2 is an enlarged view of a developing device of the image forming apparatus shown in FIG.

FIG. 3 is a schematic explanatory view of an apparatus for measuring a fluidity index of a toner.

[Explanation of symbols]

 Reference Signs List 10 latent image carrier (photosensitive drum) 11 developing device 12 first toner storage chamber (development chamber) 13 second toner storage chamber (hopper chamber) 14 partition member 15 developing sleeve 16 magnetic field generating means 17 doctor blade 18 first stirring Conveying means 19 Second stirring / conveying means 21 60-mesh sieve 22 100-mesh sieve 23 200-mesh sieve 24 Powder tester vibrating table 31 Primary charger 32 Laser oscillator 33 Laser light 34 Developing bias applying means 35 Electrostatic transfer means 36 Conveying Belt 37 Heat and pressure fixing device 38 Cleaning blade 39 Cleaner

Claims (3)

[Claims] 1. An image forming apparatus comprising: a latent image carrier for carrying an electrostatic latent image; and a developing device, wherein the developing device forms an electrostatic latent image on a developing area facing the latent image carrier. A developer carrying member for carrying a developer having a toner for development while carrying the toner; a first toner containing chamber containing toner to be supplied to the developer carrying member; and a first toner containing chamber A second toner accommodating chamber for supplying toner to the first toner accommodating chamber, and the first toner accommodating chamber communicates with the second toner accommodating chamber. A first agitating / conveying means for conveying the toner while agitating the toner is provided in the second toner accommodating chamber. Second agitation for transporting toner to the first toner storage chamber Feeding means are provided, the peripheral speed of the developer carrying member (a) is not less 250 mm / sec or more, the first stirring and carrying means following conditions [outer 1] [Where a represents the peripheral speed of the developer carrying member, and b represents the peripheral speed (mm / sec) of the first stirring means. Wherein the toner has a weight average diameter of 4 to 9 μm, a fluidity index of 20 or less, and a compression degree (Co) of 20 to 60%. 2. The image forming apparatus according to claim 1, wherein the toner has at least a binder resin and a colorant. 3. The image forming apparatus according to claim 1, wherein the toner is a triboelectrically-chargeable magnetic toner having a binder resin, a magnetic material, and a charge control agent.