JPH0611885A - Developer and developing method - Google Patents

Abstract

PURPOSE:To provide the developer with which bright images of high densities are obtainable, the change in performance does not arise during long-term use and OHP images having good light transmittability are obtainable. CONSTITUTION:This developer has a nonmagnetic toner contg. resin particles contg. at least a binder resin and coloring agents and a flow property imparting agent and a carrier. (a) In the grain size distribution of the toner, the content of the toner particles of 2.0 to 4.0mum grain sizes is 20 to 40 number % and the content of the toner particles of 4.0 to 8.0mum grain size is >=60 number %; (b) the binder resin is a polyester resin and/or styrene/acrylic resin and the acid value of the toner is >=5.0; (c) the flow property imparting agent is titanium oxide and/or alumina and (d) the electrostatic charge quantity of the toner when the toner is mixed with iron powder is -30muC/g.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developer and a developing method for developing an electrostatic latent image in an image forming method such as electrophotography and electrostatic recording.

[0002]

2. Description of the Related Art In recent years, with the widespread use of image forming apparatuses such as electrophotographic copying machines, their applications have expanded to a wide variety of applications, and the demands on their image quality have become strict. When copying an image such as a general document or photograph, it is required to reproduce extremely finely and faithfully without crushing or breaking even a minute portion. Recently, in an image forming apparatus such as an electrophotographic printer that uses a digital image signal, a latent image is formed by collecting dots, and a reproducibility of a smaller latent image is required.
Especially when a full-color image is to be obtained, the reproducibility of the latent image becomes more important because the ratio of minute dots increases in order to express a wide range of colors.

Heretofore, some developers have been proposed for the purpose of obtaining a good image. JP-A-5
In JP-A 8-129437, the average particle size is 6 to 10 μm.
A non-magnetic toner having a maximum number of particles of 5 to 8 μm has been proposed, but the number of particles of 5 μm or less is as small as 15% by number or less, and as a high resolution toner that faithfully reproduces a minute dot latent image. Still, there is still room for improvement. According to Japanese Patent Application Laid-Open No. 2-282755, toner particles of 5 μm or less clearly reproduce a minute dot latent image, and have a main function for dense toner paste on the entire latent image. It is said that particles of 5 μm or less are effective in solving the problem of highlight gradation. Based on such knowledge, Japanese Patent Laid-Open No. 2-282755 proposes a toner containing 15 to 40% by number of toner having a particle diameter of 5 μm or less.

Further, in JP-A-2-877, 5 μ
A toner containing 17 to 60% by number of toner having a particle diameter of m or less is proposed.

However, the studies by the present inventors have revealed that the inclusion of a certain amount of toner having a particle diameter of 5 μm or less does not work in all aspects. Of the toner with a particle size of 5 μm or less,
It was found that unless the toner having a particle diameter of 2.0 to 4.0 μm is set to a certain ratio or less, the fog is deteriorated and the effect of improving the image quality is canceled.

So far, there have been few discussions about toner particles having a particle size of 2.0 to 4.0 μm. Japanese Patent Laid-Open No. 60-140361 exemplifies that the toner content of particles having a particle diameter of 2.5 μm or less is 0% and 4%, but the average particle diameter at this time is as large as 9.5 μm. However, it is not possible to expect a great effect for improving the image quality as in the present invention. The claim in this publication does not include particles having a size of 1/4 or less of the average particle size. However, when this is applied to the present invention, the average particle size in the present invention is about 6 to 7 μm, so 2 μm You are discussing the smaller part. Therefore, the technology is different from the present invention. Further, in Japanese Patent Application Laid-Open No. 2-877, some data measured using a Coulter counter are illustrated, but in all cases, the toner content of 2.0 to 4.0 μm is 2
Less than 0% by number.

Further, in JP-A-2-284151, the content ratio of the toner having a particle diameter of 2.0 to 2.5 μm is exemplified. From this, the content ratio of 2.0 to 4.0 μm is measured. However, it is difficult to discuss.

Further, according to the study by the present inventors, it has been found that the image quality cannot be sufficiently improved only by controlling the particle size distribution as in these prior arts. That is, as the toner particle size becomes smaller, the charge per particle sharply decreases, and the fidelity to the latent image decreases,
The image quality does not improve as expected, or the fogging worsens in severe cases. Further, when the particle size of the toner becomes small, it is generally necessary to set the toner concentration in the developer low in order to avoid toner scattering, but this also reduces the toner supply amount to the latent image. , Hinders the improvement of image quality.

Further, according to the studies by the present inventors, when the toner particle size is reduced, the trade-off can be solved (for example, both toner scattering and image density are compatible) unless the distribution of charge is sharpened. Although it becomes difficult, it has been found that the selection of the binder resin is important in order to make the charge distribution sharp. That is, when a neutral styrene-acrylic resin or polyester having a low acid value is used to negatively charge the toner, the charge control agent must be relied upon, but in that case, the charge control agent is dispersed very uniformly. If not, the distribution of electrification becomes broad. In the case of a toner having a small particle size, this tendency becomes strong, so that a resin showing stable negative charge must be used as the binder resin.

Even if good image quality is maintained until development and transfer, the image quality of the obtained image is not improved unless the subsequent fixing is performed under good conditions. It was found that the quality was inadequate. That is, in order to improve the quality of the OHP image, it is necessary to bring the toner into a molten state so that the toner grain boundaries are not recognized at the time of fixing. However, even in such a molten state, a fixing device configuration that does not cause offset is required. Is.

[0011]

SUMMARY OF THE INVENTION An object of the present invention is to provide a developing agent and a developing method capable of obtaining an image having high image density, excellent fine line reproducibility and gradation, and no fog. .

Further, an object of the present invention is to provide a developer and a developing method capable of obtaining a high image density with a small consumption amount.

Further, an object of the present invention is to provide a developing agent and a developing method whose performance does not change with environmental changes.

Further, an object of the present invention is to provide a developing agent and a developing method which do not change in performance after long-term use.

Further, an object of the present invention is to provide a developing agent and a developing method capable of obtaining an OHP image having good translucency.

[0016]

The above objects can be achieved by the following constitutions.

That is, in a developer having a carrier and a non-magnetic toner containing at least resin particles containing a binder resin and a colorant and a fluidity-imparting agent, (a)
In the particle size distribution of the toner, the content of the toner particles having a particle size of 2.0 to 4.0 μm is 20 to 40% by number,
The content of toner particles having a particle diameter of 4.0 to 8.0 μm is 60.
% Or more, (b) the binder resin is a polyester resin and / or a styrene-acrylic resin, the toner has an acid value of 5.0 or more, and (c) the fluidity-imparting agent is an acid. This is achieved by a developer (Invention 1), which is titanium-valent and / or alumina, and has a charge amount of -30 μC / g or more when mixed with (d) iron powder.

Further, in a developer having a carrier and a non-magnetic toner containing at least resin particles containing a binder resin and a colorant and a fluidity imparting agent, (a) the toner contains at least one toner. A toner, in which a roller has a rubber-like elastic layer on its core, and at least the surface of which is made of a pair of rollers having a silicone rubber or a fluorine-containing substance, wherein the toner is (b) a particle size distribution of the toner. In the above, the content of the toner particles having a particle diameter of 2.0 to 4.0 μm is 20 to 40% by number, and the content is 4.0 to 8.0.
The content of toner particles having a particle diameter of μm is 60% by number or more, (c) the binder resin is a polyester resin, and the acid value of the toner is 5.0 or more, and (d) the toner. Of 1
Storage elastic modulus G ′ at 40 ° C. is 5 × 10 ^{3 to} 5 × 10
⁴ dyne / cm ² and a storage elastic modulus G ′ at 160 ° C. of 2 × 10 ³ to 2 × 10 ⁴ dyne / cm ² (invention 2).

Further, using these developers, a magnetic brush is formed in the developing area defined by the latent image carrier and the developer carrier so that the volume ratio of the toner particles is 5 to 20%. It is achieved by the developing method.

First, the developer of the present invention (Inventions 1 and 2)
The configuration requirements of are explained in detail.

According to the studies by the present inventors, in the toner particle size distribution, the content of the toner particles having a particle size of 2.0 to 4.0 μm is 20 to 40% by number, and the content of 4.0 to 8. 0μ
It was found that the content of the toner particles having a particle diameter of m is 60 number% or more is optimum for forming a high quality image [(a) of the present invention 1 and (b) of the present invention. )]. More preferably, the content of the toner having a particle diameter of 2.0 to 4.0 μm is 22 to 35% by number, and the toner content is 4.0 to 8.0 μm.
The content of the toner having the particle size of 65 is 65% by number or more,
It is preferable that the content of the toner having a particle diameter exceeding 0 μm is 10% by number or less.

When the particle size distribution of the toner developed into a minute latent image is measured, it is smaller than the particle size distribution of the original toner, and it is conventionally known that there are many toner particles of 5 μm or less. However, according to the study of the present inventors, it was found that the toner having a particle diameter of 2.0 to 4.0 μm needs to be controlled separately. That is, certain conditions are necessary for the toner having a particle diameter of 2.0 to 4.0 μm to exert the effect of improving the image quality, and one of them is to set the content rate within a certain appropriate range. is there.

When the content is 20% by number or more, even a minute latent image can be reproduced without protruding and the image quality is improved. However, when it exceeds 40% by number, fogging is deteriorated, and a phenomenon in which development is scarcely started even if a latent image should be present begins to occur. The reason for this is that the toner with such a small particle size is 1
That is, the amount of electric charge per particle becomes small, and it is not faithful to the electric field of the latent image. For example, 3.0μ
The toner having a particle diameter of m has a surface area that is 1/4 of that of a toner having a particle diameter of 6.0 μm, and therefore the charge amount per toner particle is
Should be 4. Thus, 2.0-4.0 μm
For the toner having a particle size of, it is necessary to strictly control the content.

It is difficult to measure the content of the toner having a particle size of 2.0 to 4.0 μm by 40% by number or less (normal condition, 100 μm aperture) with a particle size of less than 2.0 μm. The toner content will also be reduced (if a general classification method is used). It is considered that the toner having a particle diameter of less than 2.0 μm also has a large adverse effect on the image quality due to the above mechanism. Further, a toner having a particle diameter of 4.0 μm or less, particularly a toner having a particle diameter of less than 2.0 μm occupies a large surface area of the carrier for its weight, and therefore a large content causes toner scattering. From these aspects as well, the content of the toner having a particle size of 2.0 to 4.0 μm needs to be 40 number% or less.

On the other hand, the toner having a particle diameter of 4.0 to 8.0 μm contributes to the improvement of image quality and has less adverse effects, and it is preferable that the content rate is as large as possible. 60 pieces%
With the above, the effect of improving the image quality is sufficiently exhibited. Further, since the toner having this particle size is thinly and uniformly fixed on the image, the image density becomes high even with a small amount of toner. As a result, if copying is performed with the same image density, the toner consumption amount is small, and since the toner layer is thin, the transparency of the OHP image is also good.

The inventor of the present invention also includes a toner having a particle size of more than 8.0 μm, but a large toner having a particle size of more than 16 μm does not substantially contain (0% in weight distribution) because it disturbs an image. Is preferred.

Next, other constituent features of the present invention 1 will be described.

As mentioned above, the improvement of the image quality is not sufficient only by controlling the particle size distribution. The present inventors have found that the chargeability of the toner is important as a condition for improving the image quality, and it is necessary to increase the charge amount. The reason is considered to be the decrease in the amount of electric charge per particle due to the decrease in the surface area. What actually affects the image quality is the amount of charge on the toner when it is used as a developer, but it is important to give the toner itself a negative chargeability. -30μ when
It must have a charge amount of C / g [(d) of the present invention 1]. Thereby, the charge amount of the toner in the developer is different from that obtained by relying on the positive chargeability of the coating resin of the carrier, and even if the contact frequency with the carrier varies, the chargeability of the negative chargeability of a certain degree is obtained. It becomes a range as a result,
The distribution of the charge amount becomes sharp and the image quality is improved. Further, since the carrier is not relied upon, the toner has a sufficient negative charging property even when the carrier is spent due to durability, and the life of the developer is extended.

In the present invention 1, the binder resin has an acid value of 5.
0 or more polyester resin and / or styrene-
Although an acrylic resin is used, stable charging can be quickly obtained and charge-up is eliminated [Invention 1
(B)]. As a result, a high-quality image can be stably obtained, and fluctuations in image density during running are small. Among them, the polyester resin is excellent in fixability and suitable for color toners.

[0030]

[Chemical 1] (In the formula, R is an ethylene or propylene group, and x, y
Are each an integer of 1 or more, and the average value of x + y is 2 to 10. ), A bisphenol derivative or a substitution product represented by the formula (1) is used as a diol component, and a carboxylic acid component composed of a carboxylic acid having a valence of 2 or more or an acid anhydride thereof or a lower alkyl ester thereof (eg, fumaric acid, maleic acid, maleic anhydride, phthalate). An acid, terephthalic acid, trimellitic acid, pyromellitic acid, etc.) is more preferable because it has a sharp melting property.

A compound having two or more polymerizable double bonds may be mainly used as the crosslinking agent. Examples thereof include aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; carboxylic acid esters having two double bonds such as ethylene glycol acrylate; divinylaniline and divinyl ether. Also, a compound having three or more vinyl groups can be used. These cross-linking agents may be used alone or as a mixture, and as an addition amount, when the binder resin is used as a reference, 0.01 to 5 parts by weight of the binder resin may be used at the time of synthesis. In terms of

Even if a wax-like substance such as low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax, carnauba wax, sazol wax, and paraffin wax is added to the non-magnetic toner for the purpose of improving releasability at the time of heat roll fixing. good. The amount of these release agents applied is 0.1 to 8 parts by weight, preferably 0.5 to 5 parts by weight, based on the binder resin.

Furthermore, in the present invention, since a negatively chargeable resin is used, the toner shows negative chargeability without using a charge control agent, but it is preferable to add a charge control agent. As the charge control agent that can be used in the present invention, for example, an organometallic complex, a chelate compound and the like are effective, and examples thereof include aluminum acetylacetonate, iron (II) acetylacetonate and 3,5-ditertiary. There is chromium butylsalicylate. In particular, acetylacetone metal compounds (including monoalkyl-substituted compounds and dialkyl-substituted compounds) and salicylic acid-based metal compounds (including monoalkyl-substituted compounds and dialkyl-substituted compounds) are preferable, and di-tert-sali-butylsalicylic acid compounds are particularly preferable. Compounds of chromium or zinc are preferable because they do not affect the color tone of the toner.
The applied amount of these charge control agents is 0.1 to 10 parts by weight, preferably 0.5 to 8 parts by weight, based on the binder resin.

Further, in the present invention 1, titanium oxide and / or alumina is used as the fluidity imparting agent [Invention 1
(C)]. As a result, the charge amount of the toner is less likely to be affected by temperature / humidity, and even with a toner having a small particle size as in the present invention, the charge amount in a low humidity environment does not become too large. As a result, it is possible to control the charge amount suitable for obtaining a high-quality image in any environment. Titanium oxide and alumina can be obtained with a fine particle size relatively easily by a vapor phase method, but there is no particular limitation as a manufacturing method. The fluidity-imparting agent having a smaller particle size has a higher fluidity-imparting ability, but in the present invention, the one having a specific surface area of 50 m ² / g or more by the BET method and having a granular shape is preferable. preferable. Further, the one subjected to the surface hydrophobization treatment is more preferable from the viewpoints of fluidity imparting ability, stability of charging in a high humidity environment, and the like.

When silica fine powder is used as the fluidity-imparting agent, the negative charging property becomes strong in a low humidity environment, but if the particle size of the toner is made small, this tendency is promoted and the environmental difference in the charge amount increases. . Therefore, silica fine powder is not preferable for the present invention.

The fluidity-imparting agent is applied in an amount of 0.05 to 5 parts by weight, preferably 0.1 to 2 parts by weight, based on 100 parts by weight of the colorant-containing resin particles. If the amount is less than 0.05 part by weight, the image is fogged, and if the amount is more than 5 parts by weight, the toner is scattered in the machine.

Next, constituent elements according to the present invention 2 will be described.

As described above, the improvement of the image quality is not sufficient only by controlling the particle size distribution. In the present invention 2, a polyester resin having an acid value of 5.0 or more is used as the binder resin, but this makes it possible to quickly obtain stable charging and eliminate charge-up [(c) of the present invention 2]. As a result, a high-quality image can be stably obtained, and fluctuations in image density during running are small. As the polyester resin, those described above are preferably used. Further, the toner charge amount when mixed with the iron powder is preferably −30 μC / g or more.

The cross-linking agent, release agent and charge control agent are also the same as above.

In the present invention 2, the storage elastic modulus G ′ of the toner at 140 ° C. is 5 × 10 ^{3 to} 5 × 10 ⁴ dyne / c.
m ² and the storage modulus G ′ at 160 ° C. is 2 × 1
It is necessary to be 0 ^{3 to} 2 × 10 ⁴ dyne / cm ² [(d) of the present invention 2].

To measure the viscoelastic characteristics, the toner pellets are kept at a sufficient measurement temperature and then measured. On the other hand, when fixing the toner, heat is applied only for a few seconds of a comma passing between the rollers. Therefore, the viscoelastic property at a temperature lower than the actual temperature of the fixing roller has a good correlation with the tendency of fixing. The present inventors have found that the storage elastic modulus G ′ at 160 ° C. is 2 × 10 ³ to 2 × 10 ⁴ dyne / cm.
^{When the value is 2} , the image quality of the OHP image is good, and the storage elastic modulus G ′ at 140 ° C. is 5 × 10 ^{3 to} 5
It has been found that, by having a density of × 10 ⁴ dyne / cm ² , the action and effect can be exhibited even under severe conditions such as high-speed continuous fixing and immediately after warm-up.

The fixing method used in the present invention 2 is as follows.
For example, as the fixing roller, a single-layer roller of RTV (room temperature vulcanized silicone rubber) or LTV (low temperature vulcanized silicone rubber) whose rubber elastic layer is a silicone rubber type is preferable because of good wettability with the silicone type fixing oil. (A) of the present inventor 2]. When dimethyl silicone oil or the like is used as the fixing oil, HTV (high temperature vulcanizing silicone rubber) is used for the lower layer in contact with the core metal and the upper layer has good wettability with the fixing oil in order to reduce swelling by the fixing oil. R
A roller having a two-layer structure coated with a TV or LTV layer is used, and further silicone rubber (HTV) -fluorine rubber or Teflon coating layer-silicon rubber (RTV or LTV) for improving fixing oil resistance and abrasion resistance. Those having a three-layer structure such as a coating are also preferable.

If silicone oil is used as a releasing material for the fixing roller as described above, the applied state of the oil becomes uniform and the offset resistance can be dramatically improved. As a result, even the toner having a relatively small storage elastic modulus G'as described above is not offset.

Further, as the fixing method used in the present invention 2, for example, as a fixing roller, a two-layer structure in which an elastic silicone rubber HTV is provided in the lower layer and a PFA resin is provided in the upper layer, or a lower layer is used. It is also preferable that an HTV is provided on the above, a fluororesin-dispersed fluororubber layer is provided on the upper layer, and the fluororesin is segregated on the surface by heat treatment.

By using the fluorine-containing substance as the surface material of the fixing roller in this way, even a toner having a relatively small storage elastic modulus G'is unlikely to be offset.

As a result of using the fixing method excellent in offset resistance as described above, the toner on the image can be sufficiently melted, and especially the light transmittance of the OHP image becomes good. Further, in the second aspect of the invention, since the toner particle size is small, the toner powder on the unfixed image has a high cohesive property, and the image disturbance during fixing can be suppressed. Further, in the second aspect of the present invention, the toner can be sufficiently melted without slowing down the fixing process speed, but this also contributes to less disturbance of the image during fixing. Furthermore, since each toner is small, the toner can be sufficiently melted with a small amount of heat, so that the heat resistance of the OHP sheet is loosely restricted, and
It is easy to add functions to the HP sheet (moisture resistance, affinity with toner, absorption of silicone oil, etc.).

As the hardness of the fixing roller (in the case of two layers, the hardness when the two layers are combined), the rubber hardness (JIS-A) is 3
The fixing roller has a layer thickness of 0.5 to 5 mm, preferably 1.0 to 70 degrees.
It is 3.5 mm.

The pressure roller has a hardness of 40 degrees or more, preferably 50 degrees or more and is made of silicone rubber.
Any of fluororubber type and Teflon coated type can be used.

The roller diameter cannot be increased so much as it is required to downsize the copying machine. However, if the roller diameter is reduced, the nip cannot be sufficiently opened, and it becomes difficult to sufficiently melt the toner. Therefore, the diameter of the fixing roller and the pressure roller is 40
-80 mmφ is suitable.

The fixing device used in the present invention 2 is as follows.
When a blank sheet is passed, it is preferable that the sheet discharge direction is on the pressure roller side by the direction perpendicular to the line connecting the centers of the fixing roller and the pressure roller.

As a method of setting the paper discharge direction to the pressure roller side, for example, the hardness of the pressure roller is made higher than the hardness of the fixing roller. As a method of increasing the hardness of this pressure roller,
a. A method of increasing the hardness of the elastic body, b. There is a method of thinning the elastic layer. The diameter of the fixing roller is larger than that of the pressure roller. And so on.

Further, by mounting the heating device not only on the fixing roller side but also on the pressure roller side, it is possible to remarkably reduce the "wrinkle".

In the present invention, the volume ratio of the toner particles is 5 to 5 in the developing area defined by the latent image carrier and the developer carrier.
A magnetic brush is formed so as to be 20%. It is more preferably 6 to 15%. The present inventors have found that it is preferable to control the toner supply amount in the vicinity of the latent image within a certain range in order to faithfully develop the latent image. The volume ratio of toner particles is calculated by the following formula.

(M / h) × (1 / ρ) × (T / (T +
C)) × σ × 100 where M is the coating amount of the developer per unit area of the developer carrier (sleeve) (g / cm ² ), and h is the closest contact between the latent image carrier and the developer carrier. The distance (cm), ρ is the true density of toner particles (g / cm ³ ), T / (T + C) is the toner concentration (weight ratio) of the developer, and σ is the peripheral speed ratio of the latent image carrier and the developer carrier. (Peripheral speed of developer carrying member / peripheral speed of latent image holding member).

When the volume ratio of the toner particles is less than 5%, the toner is less supplied to the latent image, so that the effect of reducing the toner particle size is not sufficiently exerted.
High quality images cannot be obtained. Further, the amount of toner particles attached to the latent image carrier becomes too small, and the conditions for transfer to paper, separation of paper, and cleaning of toner become strict.

On the contrary, when the volume ratio of the toner is more than 20%, the adhesion of the toner to the non-image area is increased and the fog is deteriorated, and the toner developed in the image area is excessive, resulting in a faithful latent image. It cannot be reproduced. In addition, the developed toner layer becomes thick and the transparency of the OHP deteriorates, and the toner consumption also increases.

The colorants used in the present invention include carbon black, lamp black, iron black, ultramarine blue, nigrosine dye, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa yellow G, rhodamine 6
Conventionally known dyes and pigments such as G, rhodamine lake, chalco oil blue, chrome yellow, quinacridone, benzidine yellow, rose bengal, triarylmethane dyes, monoazo dyes and disazo dyes may be used alone or in combination.

The following additives are used as the additives used in the present invention for the purpose of imparting various characteristics. 1) Abrasives: metal oxides (strontium titanate, cerium oxide, aluminum oxide, magnesium oxide, chromium oxide, etc.), nitrides (silicon nitride, etc.), carbides (silicon carbide, etc.), metal salts (calcium sulfate, barium sulfate, etc.) , Calcium carbonate) etc. 2) Lubricants: Fluorine-based resin powders (vinylidene fluoride, polytetrafluoroethylene, etc.), fatty acid metal salts (zinc stearate, calcium stearate, etc.), etc. 3) Charge control particles: Metal oxides (tin oxide, titanium oxide, zinc oxide, silicon oxide, aluminum oxide, etc.)
Carbon black / spherical resin particles (particle size 0.05 to 3
μm) etc.

These additives are used in an amount of 0.1 to 10 parts by weight, preferably 100 parts by weight of the toner particles.
0.1-5 parts by weight are used. These additives may be used alone or in combination.

As the carrier which can be used in the present invention, known carriers can be used, for example, iron powder, ferrite powder, magnetic powder such as nickel powder, glass beads and the like, and the surface thereof is resin. And the like. Further, as the resin for coating the carrier surface, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, acrylic acid ester copolymer, methacrylic acid ester copolymer, silicone resin,
Fluorine-containing resin, polyamide resin, ionomer resin,
A polyphenylene sulfide resin or the like or a mixture thereof can be used. As a preferable mixing ratio of the carrier and the toner, it is preferable to mix 30 to 500 parts by weight of the carrier with 10 parts by weight of the toner. The particle size of the carrier is preferably 5 to 80 μm.

To prepare the non-magnetic toner of the present invention, a binder resin, and if necessary, a colorant, a charge control agent and other additives are thoroughly mixed with a mixer such as a Henschel mixer, and then heated rolls are used. It can be obtained by thoroughly kneading the constituent materials using a heat kneader such as a kneader or an extruder, then mechanically crushing and classifying.
Alternatively, a method in which a material such as a colorant is dispersed in a binder resin solution and then spray-dried, or a monomer to form the binder resin is mixed with a predetermined material and then suspension-polymerized The toner can also be obtained by a method such as a method for producing a polymerized toner.

The measuring method of the present invention will be described below.

(1) Particle size distribution measurement The particle size distribution of the toner can be measured by various methods.
In the present invention, it is suitable to use a Coulter counter.

That is, a Coulter counter TA-II type (manufactured by Coulter) is used as a measuring device, and an interface (manufactured by Nikkaki) for outputting number distribution and volume distribution and a CX-1 personal computer (manufactured by Canon) are connected. As the electrolytic solution, an approximately 1% NaCl aqueous solution is prepared using first-grade sodium chloride. For example, ISOTO
NR-II (manufactured by Coulter Scientific Japan) can be used. As a measuring method, the electrolytic solution 1
0.1 to 5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant to 0 to 150 ml, and 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment for about 1 to 3 minutes with an ultrasonic disperser, and is subjected to a Coulter Counter TA-II type
Using a 100 μm aperture as an aperture, the volume and number of toner were measured to calculate the volume distribution and number distribution of particles of 2 to 40 μm. Then, the content ratio of the number-based fine powder according to the present invention (2.0 to 4.0 μm,
4.0 to 8.0 μm) was obtained.

(2) Measurement of triboelectric charge amount The measuring method will be described in detail with reference to the drawings.

FIG. 1 is an explanatory view of an apparatus for measuring the amount of toner charge. First, about 20 g of a mixture (weight ratio 1:19) of toner and iron powder (EFV 200 300) whose triboelectric charge is to be measured is put in a polyethylene bottle having a capacity of 50 ml and shaken by hand 500 times. About 0.5 g of the mixture is placed in a metal measuring container 12 having a 500-mesh screen 13 at the bottom, and a metal lid 14 is placed on it. At this time, the entire measuring container is weighed to obtain W ₁ (g). Next, in the suction device 11 (at least the portion in contact with the measurement container 12 is an insulator), suction is performed from the suction port 17 (the air volume control valve 16 is adjusted to adjust the pressure of the vacuum gauge 15 to 250).
mmAq). In this state, suction is carried out for 1 minute or more, preferably 2 minutes to suck and remove the toner. The potential of the electrometer 19 at this time is V (volt). Here, 18 is a capacitor, and the capacitance is C (μF). Next, the total weight of the measuring container after suction is weighed to obtain W ₂ (g). The triboelectric charge amount (μC / g) of this toner is calculated by the following formula.

[0067]

[Equation 1] The toner and iron powder to be measured are those left for 12 hours or more in an environment of 23 ° C. and 60% RH. Also, the shaking and measurement environments are 23 ° C. and 60% RH.

(3) Measurement of acid value A method applying the acid value measurement of JIS K-0070 or the like can be used, and it is expressed in mg of potassium hydroxide necessary to neutralize 1 g of resin.

(4) Rubber Hardness Measurement The hardness of the rubber layer was determined by the spring type hardness test A type in the JIS vulcanized rubber physical test method.

(5) Measurement of storage elastic modulus G ′ A dynamic viscoelasticity measuring device such as RMS-800 manufactured by Rheometric Co. is used. A sample 1 of about 1 g was fixed between the plates 2 in a parallel rate test fixture as shown in FIG. 2, and a torsional reciprocating vibration strain of 100 rad / sec was applied from one side (input 3), and the stress against this strain was detected on the other side. Yes (output 4). Distortion rate is automatic (maximum 10
%). In this state, the temperature was raised and the temperature dependence of the storage elastic modulus G ′ was measured. From this result, the values at 140 ° C. and 160 ° C. were obtained.

[0071]

EXAMPLES The present invention will be specifically described below with reference to examples. All parts in the following formulations are parts by weight.

Example 1 Polyester resin C.I. obtained by condensing 100 parts of propoxylated bisphenol and fumaric acid. I. Pigment Blue 15: 3 5 parts Di-tert-butylsalicylic acid chromium complex salt 4 parts The above materials are sufficiently premixed by a Henschel mixer, melt-kneaded three times with a three-roll mill, and after cooling, about 1 to 1 using a hammer mill. It was roughly pulverized to about 2 mm and then finely pulverized by an air jet type fine pulverizer. further,
The obtained finely pulverized product was classified to obtain colorant-containing resin particles.

To 100 parts of the obtained resin particles, 1.2 parts of hydrophobic titanium oxide (BET specific surface area of 100 m ^{2 /} g) was mixed with a Henschel mixer to prepare a toner.

The data of the particle size distribution of the obtained toner are shown in Table 1.
Shown in.

When the charge amount of this toner when mixed with iron powder was measured, it was -46 μC / g. The acid value of the toner was measured and found to be 9.0.

50% styrene, 2 methyl methacrylate
A carrier composed of 0% and 30% of 2-ethylhexyl acrylate was coated on a Cu—Zn—Fe ferrite carrier having a weight average diameter of 35 μm in an amount of 0.5 wt%.

95 parts of this carrier and 5 parts of the above toner were mixed to prepare a developer.

Using this developer, a commercially available plain paper color copying machine (color laser copier 500) was modified to produce an image. The peripheral speed of the photosensitive drum was 160 mm / sec, and the peripheral speed of the sleeve was 320 mm / sec. An AC component having a frequency of 2.2 kHz and a peak-to-peak potential difference of 2.0 kV was applied to the sleeve. The volume ratio of the toner in the developing area was 11%.

The obtained image had a high density of 1.45 and was clear without any fog. At this time, when a minute latent image was formed on the photosensitive drum and the developing state of the toner was observed, it was confirmed that even dots having an average diameter of about 20 μm had the same size and shape. Also, OHP
The translucency of the image was also good. After that, 5000 more copies were made, but the fluctuation of the image density during that time was as small as 0.1, the toner consumption was small, and the economy was excellent. Further, the images after 5,000 sheets had almost the same fog and sharpness as the initial images.

[0080]

[Table 1] Comparative Example 1 Images were produced in the same manner as in Example 1 except that the conditions of fine pulverization / classification in Example 1 were changed to the particle size distribution shown in Table 2 and the amount of titanium oxide added was set to 0.9%. I went.

The charge amount of the toner when mixed with iron powder is -3.
It was 4 μC / g, and the volume ratio of the toner in the developing area was 10%.

The obtained image had a high density of 1.52 and was clear without fog. However, in the smoothness of the highlight portion, which is a collection of minute dots, Example 1 was used.
Inferior to Even when observing the developability for minute latent images,
The dot size and shape were more uneven than in Example 1. The light transmittance of the OHP image was also lower than that in Example 1.

[0083]

[Table 2] Comparative Example 2 Image formation was performed in the same manner as in Example 1 except that the mixing ratio of the toner and the carrier was changed to 97 parts of the carrier for 3 parts of the toner and the peripheral speed of the sleeve was 200 mm / sec. .

The volume ratio of the toner in the developing area is 3.
It was 8%.

The obtained image had a low density of 1.27, and the smoothness of the highlight portion was inferior to that of Example 1. In addition, the size and shape of the dots were more uneven than in Example 1 when the developability of a minute latent image was observed.

Comparative Example 3 Resin particles were obtained in the same manner as in Example 1 except that the formulation was as follows.

Polyester resin C. obtained by condensing 100 parts of propoxylated bisphenol and fumaric acid. I. Pigment Blue 15: 3 5 parts Chromium complex salt of di-tert-butylsalicylic acid 1 part To 100 parts of the obtained resin particles, 1.3 parts of alumina (BET specific surface area of 150 m ^{2 /} g) was mixed with a Henschel mixer to obtain a toner. .

The data of the particle size distribution of the obtained toner are shown in Table 3.
Shown in. The toner charge when mixed with iron powder is -28μ
It was C / g. The acid value of the toner was 5.5.

The obtained image had a high density of 1.60, but was inferior to Example 1 in the smoothness of the highlight portion, which is a collection of minute dots. Even in the observation of the developability for a minute latent image, the size and shape of the dots were more uneven than in Example 1.

Example 2 In the same manner as in Example 1, yellow toner, magenta toner and black toner were obtained.

Yellow toner The colorant is C.I. I. Pigment Yellow 17 Same as above, except for 4 parts.

Content of toner having a particle size of 2.0 to 4.0 μm 25.0% by number 2 Content of toner having a particle size of 4.0 to 8.0 μm 67.0% by number When mixed with iron powder Toner charge amount −50 μC / g Toner acid value 9.0 4 parts of this toner and 96 parts of the same carrier as in Example 1 were mixed to prepare a developer. The volume ratio of toner in the developing area is 10
%Met.

Magenta toner The colorant is C.I. I. Pigment Red 122 Same as above, except that it is changed to 5 parts. Content of toner having a particle size of 2.0 to 4.0 μm 26.1 number% Content of toner having a particle size of 4.0 to 8.0 μm 68.7 number% Charging of toner when mixed with iron powder Amount-44 μC / g Toner acid value 8.9 This toner was used as a developer in the same manner as in Example 1. The volume ratio of the toner in the developing area was 11%.

Black toner: Colorant is carbon black (particle size 40 μm, volatile content 3
%) Same as above except changed to 8 parts.

Content of toner having a particle diameter of 2.0 to 4.0 μm 27.5 number% Content of toner having a particle diameter of 4.0 to 8.0 μm 70.3 number% When mixed with iron powder Toner charge amount −43 μC / g Toner acid value 8.9 This toner was used as a developer in the same manner as in Example 1. The volume ratio of the toner in the developing area was 10%.

Using these developers, full color images were formed in the same manner as in Example 1. The resulting image is
The color reproducibility of the part where the minute dots of each color such as the skin color overlap was good, and the dots were uniform, resulting in a smooth color. When each color alone was evaluated, the image density of the yellow toner was 1.53, and the observation of the developability for fogging and a minute latent image was as good as in Example 1. The magenta toner had an image density of 1.48, and was as good as in Example 1 in the observation of the developability with respect to fog and a minute latent image. The image density of the black toner was 1.47, and the observation of the developability with respect to fog and a minute latent image was as good as in Example 1. After that, 5000 copies were made, but the fluctuation of the image density during that period was small and the toner consumption was also small. Furthermore, the color reproducibility,
Fog and sharpness were almost the same as in the initial stage.

Example 3 The same as Example 1 except that the conditions of fine pulverization / classification of Example 1 were changed to obtain the particle size distribution shown in Table 3 and the addition amount of titanium oxide was 1.4%. Drawing out. The charge amount of the toner when mixed with the iron powder was −52 μC / g, and the volume ratio of the toner in the developing area was 10%.

The obtained image had a high density of 1.50 and was clear without fog. The smoothness of the highlight portion, which is a collection of minute dots, was also good as in Example 1. However, when the developability of a minute latent image was observed, the size and shape of the dots were slightly more uneven than in Example 1.

Example 4 Polypropoxylated bisphenol, phthalic acid, trimester 100 parts Polyester resin obtained by condensing ritonic acid Carbon black (particle size 30 μm, volatile content 2%) 5 parts Low molecular weight propylene-ethyl copolymer 3 Part Chromium complex salt of disazu dye 4 parts The above materials were sufficiently premixed by a Henschel mixer and kneaded by a twin-screw kneading extruder. After cooling, it was roughly pulverized to about 1 to 2 mm using a hammer mill, and then finely pulverized by an air jet type fine pulverizer. Furthermore, the obtained finely pulverized product was classified to obtain colorant-containing resin particles.

To 100 parts of the obtained resin particles, 1.0 part of hydrophobic alumina (BET specific surface area of 150 m ^{2 /} g) was mixed with a Henschel mixer to obtain a toner.

The data of the particle size distribution of the obtained toner are shown in Table 3.
Shown in. The toner charge when mixed with iron powder is -40μ
It was C / g. The acid value of the toner was 11.0.

The mixing ratio of the toner and the carrier is toner 4
Carrier for the part (the same as that of the first embodiment) 96
Part and

A plain paper copying machine N available on the market using this developer.
P-7550 was remodeled and images were displayed. An AC component having a frequency of 2.0 kHz and a peak-to-peak potential difference of 1.5 kV was applied to the sleeve. The volume ratio of the toner in the developing area was 8%.

The obtained image had a high density of 1.40 and was clear without any fog. 100 more after that
Copies of 00 sheets were made, but the fluctuation of the image density during that time was 0.
The image after 10 000 sheets, which is as small as 05 and the toner consumption amount is small, is almost the same as the initial image in fog and sharpness.

Example 5 In Example 4, the binder resin was a styrene / butyl acrylate / methacrylic acid / divinylbenzene copolymer (copolymerization weight ratio 80 / 17.5 / 2.0 / 0.5, weight average). Image formation was carried out in the same manner as in Example 4 except that the amount was changed to 100 parts.

The charge amount of the toner when mixed with iron powder is -4.
4 μC / g, and the toner volume ratio in the developing area was 11%. The acid value of the toner was 9.0.

The image obtained in the initial stage has a density of 1.3.
The image density was as high as 7, and was clear without fogging, but the variation in image density was 0.15, which was larger than that in Example 4. In addition, the images after 10,000 sheets had almost the same fog and sharpness as the initial images.

[0108]

[Table 3] Example 6 Polyester resin obtained by condensing 100 parts of propoxylated bisphenol and fumaric acid Phthalimide methylated copper phthalocyanine pigment 5 parts Di-tert-butylsalicylic acid chromium complex salt 4 parts The above materials were thoroughly premixed with a Henschel mixer. The mixture was melt-kneaded three times with a three-roll mill and further kneaded with a twin-screw kneading extruder. After cooling about 1 using a hammer mill
Coarsely pulverized to about 2 mm, and then finely pulverized by an air jet type fine pulverizer. Furthermore, the obtained finely pulverized product was classified to obtain colorant-containing resin particles.

To 100 parts of the obtained resin particles, 1.2 parts of hydrophobic titanium oxide (BET specific surface area of 150 m ^{2 /} g) was mixed with a Henschel mixer to obtain a toner. The acid value of the toner was 10.0.

Table 4 shows the data of the particle size distribution of the obtained toner.
Shown in.

[0111]

[Table 4] The storage elastic modulus G ′ of this toner is 1.
7 × a 10 ⁴ dyne / cm ^2, was 4.9 × 10 ³ dyne / cm ² at 160 ° C..

50% styrene, 2 methyl methacrylate
A carrier composed of 0% and 30% of 2-ethylhexyl acrylate was coated on a Cu—Zn—Fe ferrite carrier having a weight average diameter of 35 μm in an amount of 0.5 wt%.

95 parts of this carrier and 5 parts of the above toner were mixed to prepare a developer.

Using this developer, a commercially available plain paper color copying machine (color laser copier 500) was modified to produce an image. The peripheral speed of the photosensitive drum was 160 mm / sec, and the peripheral speed of the sleeve was 320 mm / sec. An AC component having a frequency of 2.2 kHz and a peak-to-peak potential difference of 2.0 kV was applied to the sleeve. The volume ratio of the toner in the developing area was 12%. The fixing roller has a structure in which silicone rubber (HTV) -fluorine rubber-silicone rubber (RTV) is coated in this order.
The thickness of the rubber-like elastic layer is 3.0 mm, the rubber hardness of the entire rubber-like elastic layer is 45 degrees, and the roller diameter is 60.
The one with mmφ was used. Further, a fluororubber roller having a layer thickness of 1 mm, a rubber hardness of 55 degrees and a roller diameter of 60 mmφ was used as a roller. Silicon oil was applied to the surface of the fixing roller as a releasing agent.

The obtained image had a high density of 1.55 and was clear without any fog. Further, the OHP image showed a good light-transmitting property because the toner layer was thin, and the image quality was also good. After that, 5000 more copies were made, but the fluctuation of the image density during that time was as small as 0.1, the toner consumption was small, and the economy was excellent. Further, the images after 5000 sheets were almost the same as the initial images.

Comparative Example 4 Example 6 was repeated except that the conditions for fine pulverization and classification in Example 6 were changed to obtain the particle size distribution shown in Table 5 and the addition amount of titanium oxide was set to 0.9%. Drawing out. The volume ratio of the toner in the developing area was 9%.

The obtained image had a high density of 1.53 and was clear without fog. However, in Example 6 in the smoothness of the highlight portion, which is a collection of minute dots.
Inferior to In addition, the optical transparency of the OHP image is also shown in Example 6.
Was lower than

Comparative Example 5 In the same manner as in Example 6, except that the mixing ratio of the toner and the carrier was changed to 97 parts of the carrier to 3 parts of the toner and the peripheral speed of the sleeve was set to 200 mm / sec, the image formation was performed in the same manner. went.

The toner volume ratio in the developing area is 4%.
Met.

The obtained image had a low density of 1.25 and the smoothness of the highlight portion was inferior to that of Example 6. Further, in the OHP image, the adhesion of the fixing oil was conspicuous, and the transparency of the non-image portion was uneven.

[0121]

[Table 5] Example 7 In the same manner as in Example 6, yellow toner, magenta toner and black toner were obtained.

Yellow toner The colorant is C.I. I. Pigment Yellow-17, except that it has been changed to Part 4.

Content of toner having a particle diameter of 2.0 to 4.0 μm 26.5 number% Content of toner having a particle diameter of 4.0 to 8.0 μm 69.2 number% Acid value of toner 10.0 The storage elastic modulus G ′ of this toner is 1.
It was 6 × 10 ⁴ dyne / cm ² and 4.8 × 10 ³ dyne / cm ² at 160 ° C.

4 parts of this toner and 96 parts of the same carrier as in Example 6 were mixed to prepare a developer. The volume ratio of the toner in the developing area was 10%.

Magenta toner The colorant is C.I. I. Pigment Red 122 Same as above, except that it is changed to 5 parts.

Content of toner having a particle diameter of 2.0 to 4.0 μm 27.6 number% Content of toner having a particle diameter of 4.0 to 8.0 μm 70.5 number% Acid value of toner 9.8 The storage elastic modulus G ′ of this toner is 1.
It was 7 × 10 ⁴ dyne / cm ² and 5.0 × 10 ³ dyne / cm ² at 160 ° C.

This toner was used as a developer in the same manner as in Example 6. The volume ratio of the toner in the developing area was 11%.

Black toner Carbon black (particle size 40 μm, volatile content 3
%) Same as above, except for 6 parts.

Content of toner having a particle size of 2.0 to 4.0 μm 25.1 number% Content of toner having a particle size of 4.0 to 8.0 μm 67.2 number% Acid value of toner 9.9 The storage elastic modulus G ′ of this toner is 1.
It was 8 × 10 ⁴ dyne / cm ² and 5.0 × 10 ³ dyne / cm ² at 160 ° C.

This toner was used as a developer in the same manner as in Example 6. The volume ratio of the toner in the developing area was 10%.

Using these developers, full color images were formed in the same manner as in Example 6.

The obtained image had a good color reproducibility in a portion where fine dots of each color such as a flesh color overlap, and was a smooth color because the dots were uniform. In addition, the light transmittance of the OHP image was also good. After that, 5000 copies were made, but the fluctuation of the image density during that period was small and the toner consumption was also small. Further, the image after 5000 sheets was almost the same as the initial image.

Example 8 Example 8 was carried out in the same manner as in Example 6 except that the conditions of fine pulverization and classification were changed to the particle size distribution shown in Table 6 and the amount of titanium oxide added was changed to 0.9%. Drawing out.

The toner volume ratio in the developing area is 11
%Met.

The obtained image had a high density of 1.50 and was clear without fog. The smoothness of the highlight portion, which is a collection of minute dots, was also good as in Example 6. However, when the developability of a minute latent image was observed, the dot size and shape were slightly more uneven than in Example 6.

Example 9 In Example 6, the fixing roller is made of silicone rubber (HT
Image formation was performed in the same manner as in Example 6 except that V) was coated with PFA resin in a thickness of 30 μm and had a rubber hardness of 55 degrees and a roller diameter of 60 mmφ.

The obtained image had a high density of 1.44 and was clear without fogging, and the transparency of the OHP image was good. However, when the stain of the fixing web was observed after 5000 sheets, the stain level was worse than that of Example 6 although it was within the practical range.

Comparative Example 6 Polyester resin obtained by condensing propoxylated bisphenol with phthalic acid and trime 100 parts Lit acid phthalimidomethylated copper phthalocyanine pigment 5 parts Low molecular weight propylene-ethyl copolymer 3 parts Chromium complex salt of monoazo dye 4 parts The above materials were sufficiently premixed with a Henschel mixer and kneaded with a twin-screw kneading extruder. After cooling, it was roughly pulverized to about 1 to 2 mm using a hammer mill, and then finely pulverized by an air jet type fine pulverizer. Furthermore, the obtained finely pulverized product was classified to obtain colorant-containing resin particles.

To 100 parts of the obtained resin particles, 1.0 part of hydrophobic titanium oxide (BET specific surface area of 150 m ^{2 /} g) was mixed with a Henschel mixer to obtain a toner. The acid value of the toner was 11.0.

Table 6 shows the data of the particle size distribution of the obtained toner.
Shown in.

The storage elastic modulus G ′ of this toner is 140 ° C.
At 2.6 × 10 ⁵ dyne / cm ² , and 16
It was 1.5 × 10 ⁵ dyne / cm ² at 0 ° C.

Using this toner, images were formed in the same manner as in Example 6. The volume ratio of the toner in the developing area was 10%.

The obtained image had a high density of 1.40, but the OHP image had poor light transmittance.

Comparative Example 7 In Example 6, the binder resin was a styrene / butyl acrylate / divinylbenzene copolymer (copolymerization weight ratio 80 /
Image formation was carried out in the same manner as in Example 6 except that the amount was changed to 19.5 / 0.5 and the weight average molecular weight was 300,000).
Table 6 shows the data of the particle size distribution of the obtained toner.

The storage elastic modulus G ′ of this toner is 140 ° C.
At 2.8 × 10 ⁴ dyne / cm ² , and 16
It was 1.0 × 10 ⁴ dyne / cm ² at 0 ° C.

The toner volume ratio in the developing area is 12
%Met.

The image obtained in the initial stage has a density of 1.3.
The image density was as high as 7, and was clear without fogging, but the fluctuation of the image density was as large as 0.25, and uneven density occurred in the image after 1000 sheets. It is considered that this is because the toner is unevenly charged.

[0148]

[Table 6]

[0149]

According to the present invention, it is possible to obtain a clear and high-density image, and to obtain an OHP image having a good light-transmitting property without any change in performance after a long period of use.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an apparatus that measures a toner charge amount.

FIG. 2 is an explanatory diagram of a dynamic viscoelasticity measuring device.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location G03G 9/08 331

Claims (4)

[Claims] 1. A developer having a non-magnetic toner containing at least resin particles containing a binder resin and a colorant and a fluidity-imparting agent and a carrier, wherein (a) the particle size distribution of the toner is 2 The content of toner particles having a particle diameter of 0.0 to 4.0 μm is 20 to 40% by number, and
The content of the toner particles having a particle size of 8.0 μm is 60% by number or more, the acid value of the toner is 5.0 or more,
(B) The binder resin is a polyester resin and / or a styrene-acrylic resin, and the toner has an acid value of 5.0.
And (c) the fluidity-imparting agent has an acid value of titanium and / or
Alternatively, the developer is alumina, and the charge amount of the toner when mixed with the iron powder (d) is −30 μC / g or more. 2. A developing method in which a magnetic brush is formed in a developing region defined by the latent image carrier and the developer carrier so that the volume ratio of the toner particles is 5 to 20%. A developing method characterized by using the developer according to item 1. 3. A developer having a non-magnetic toner containing at least resin particles containing a binder resin and a colorant and a fluidity imparting agent, and a carrier, wherein (a) the toner contains at least one toner. A toner, in which a roller has a rubber-like elastic layer on its core, and at least the surface material of which is a silicone rubber or a fluorine-containing substance, is fixed by (b) a particle size distribution of the toner. , The content of the toner particles having a particle diameter of 2.0 to 4.0 μm is 20 to 40% by number, and the content is 4.0 to 8.0 μm.
The content of toner particles having a particle diameter of m is 60% by number or more, (c) the binder resin is a polyester resin, and the acid value of the toner is 5.0 or more, and (d) the toner. Of 1
Storage elastic modulus G ′ at 40 ° C. is 5 × 10 ^{3 to} 5 × 10
⁴ dyne / cm ² and a storage elastic modulus G ′ at 160 ° C. of 2 × 10 ³ to 2 × 10 ⁴ dyne / cm ² , a developer. 4. The developing method according to claim 3, wherein a magnetic brush is formed in a developing region defined by the latent image carrier and the developer carrier so that the volume ratio of the toner particles is 5 to 20%. A developing method characterized by using the developer according to item 1.