JPH11218963A - Image forming method - Google Patents

Abstract

(57) [Abstract] (with correction) [Problem] To form an image having excellent offset resistance, a uniform toner coat layer free of blotches on a toner carrier, and good image characteristics stably for a long period of time. Provide a way. SOLUTION: A positively chargeable toner 10 containing a binder resin for toner, a colorant and a charge control agent is transported by a toner carrier 14 having a resin layer 13 on a metal substrate 12, and the electrostatic latent image carrier is provided. In the image forming method for forming the toner image by transferring the positively chargeable toner from the toner carrier to the electrostatic latent image formed on the toner image and developing the toner image, the binder resin has an acid value of the entire polymer component. 0.5mgKOH / g to 50mgK
OH / g, and the charge control agent is characterized by having an imidazole derivative represented by the following general formula (1).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming method including a step of developing an electrostatic image formed by electrophotography, electrostatic recording, and magnetic recording using toner.

[0002]

2. Description of the Related Art Conventionally, electrophotography has been disclosed in U.S. Pat. No. 2,297,691, Japanese Patent Publication No. 42-23910.
Many methods are known as described in Japanese Patent Application Laid-Open Publication No. Sho 43-24748, and the like. Generally, a photoconductive substance is used and an electric latent image ( Electrostatic latent image), then developing the latent image using toner, and transferring the toner image to a transfer material such as paper as needed, and then applying heat, pressure, heat and pressure, or solvent vapor. The toner is fixed to obtain a copy, and the toner remaining on the photoreceptor without being transferred is cleaned by various methods, and the above steps are repeated.

In recent years, such copying apparatuses have been strictly pursued to be smaller, lighter, faster, and have higher reliability, reflecting changing market needs such as compounding and personalization. As a result, the performance required of the toner has been further enhanced.

For example, various methods and apparatuses have been proposed and developed with respect to a process of fixing a toner image on a transfer sheet such as paper, but the most common method is a heat-compression method using a heat roller. In the heat-compression bonding method using a heat roller, fixing is performed by passing a toner image of a sheet to be fixed under pressure onto a surface of a heat roller having a surface formed of a material having releasability from toner. In this method, since the surface of the heat roller and the toner image of the sheet to be fixed come into contact with each other under pressure, the thermal efficiency when fixing the toner image on the sheet to be fixed is extremely good.
Fixing can be performed quickly.

However, the heat roller fixing method, which has been widely used in the prior art, is inferior in fixing due to the temperature of the heat roller fluctuating due to the passage of a transfer material or other external factors, and the transfer of toner to the heat roller. In order to prevent the so-called offset phenomenon, it is necessary to maintain the heating roller in the optimal temperature range, and for this purpose, the heat capacity of the heating roller or the heating element must be increased, which requires large power. In addition, the size of the image forming apparatus is increased and the temperature inside the apparatus is increased.

Therefore, various means have been proposed for the purpose of preventing toner from adhering to the surface of the fixing roller or improving low-temperature fixing property. For example, the surface of the roller is formed of a material with excellent releasability from toner, such as silicone rubber or fluororesin, and the releasability such as silicone oil is used to prevent offset and prevent the roller surface from fatigue. The roller surface is coated with a thin film of a good liquid. However,
Although this method is extremely effective in preventing toner offset, it requires a device for supplying an anti-offset liquid, so that the fixing device also becomes complicated and the device becomes large. doing.

Therefore, in order to realize an efficient fixing method while achieving good fixability of a toner-visible image to a transfer material, prevention of offset, and the like, in addition to the above-described fixing device, the toner The area that depends on the characteristics becomes very large.

In other words, particularly from the viewpoint of the technology for preventing offset, it is not preferable to use an anti-offset method by supplying an anti-offset liquid. Rather, it is strongly desired to develop a toner having a wide fixing temperature range and high anti-offset property. It is the current situation. Therefore, in order to increase the releasability of the toner itself, a method of adding a wax such as a low-molecular-weight polyethylene or a low-molecular-weight polypropylene, which sufficiently melts when heated, has also been performed. , And the charging characteristics become unstable, which tends to cause a decrease in developability during durability.
Therefore, various attempts have been made to improve the binder resin as other methods.

For example, there is known a method of increasing the glass transition temperature (Tg) and the molecular weight of the binder resin in the toner in order to prevent offset, and improving the melt viscoelasticity of the toner. However, when the offset phenomenon is improved by such a method, the developing property does not significantly affect but the fixing property becomes insufficient, and the fixing property at a low temperature required for high-speed development and energy saving, that is, There is a problem that the low-temperature fixability is poor.

In order to improve the low-temperature fixability of the toner, it is necessary to reduce the viscosity of the toner at the time of melting and increase the contact area with the fixing member. For this purpose, the Tg and the molecular weight of the binder resin used are reduced. Is required.

That is, since the low-temperature fixing property and the offset resistance have one side contradictory to each other, it is very difficult to develop a toner satisfying these functions at the same time.

In order to solve this problem, for example, Japanese Patent Publication No. Sho 51-23354 discloses a toner comprising a suitably crosslinked vinyl polymer by adding a crosslinking agent and a molecular weight modifier. Many blended toners based on a combination of Tg, molecular weight, and gel content have been proposed.

The toner containing such a crosslinked vinyl polymer or gel component exhibits an excellent effect on offset resistance. However, when the crosslinked vinyl polymer is used as a raw material for the toner in containing these components, the internal friction in the polymer becomes extremely large in the melt-kneading step in the production of the toner, and a large shear force is applied. It takes unity. For this reason, in many cases, the molecular chains are cut, resulting in a decrease in the melt viscosity and adversely affecting the offset resistance.

To solve this problem, Japanese Patent Laid-Open Publication No.
Nos. 5-90509 and 57-178249,
In JP-A-57-178250 and JP-A-60-4946, a resin having a carboxylic acid and a metal compound are used as toner raw materials, and are heated and reacted at the time of melt-kneading to form a crosslinked polymer to be contained in the toner. Has been introduced.

Japanese Patent Application Laid-Open No. Sho 61-1986 discloses that a binder having a vinyl resin monomer and a more specific monoester compound as essential constitutional units is reacted with a polyvalent metal compound and crosslinked via a metal. No. 110155, 61-
It is disclosed in Japanese Patent Publication No. 110156.

Also, JP-A-63-214760,
JP-A-63-217362, JP-A-63-217363 and JP-A-63-217364 have a molecular weight distribution which is divided into two groups of a low molecular weight and a high molecular weight. It is disclosed that a valent metal ion is reacted and crosslinked (a dispersion of a metal compound is added to a solution obtained by solution polymerization, and the mixture is heated and reacted).

Further, Japanese Patent Application Laid-Open Nos. 2-168264, 2-23569 and 5-173363,
In JP-A-5-173366 and JP-A-5-241371, the molecular weight, the mixing ratio, the acid value and the ratio of the low molecular weight component and the high molecular weight component in the binder resin are controlled, and the fixing property, the offset resistance and the like are controlled. Improved toner binder compositions and toners have been proposed.

In Japanese Patent Application Laid-Open No. 62-9256,
A binder composition for a toner in which two kinds of vinyl resins having different molecular weights and resin acid values are blended is disclosed.

Although these proposals described above have advantages and disadvantages in terms of improving the offset resistance, it is true that excellent effects can be obtained. But,
Since these introduce an acid value into the toner binder, they impart a negative charge to the toner although there are some differences.
As a result, when applied to a positive toner, the charging characteristics of the toner at the start-up and endurance thereof or in a high humidity or low humidity environment are significantly impaired, and the development characteristics such as image density and fog are lowered. Further, the toner does not stably maintain an appropriate charge amount, thereby causing an increase in toner cohesiveness and the like, so that satisfactory results have not been obtained.

On the other hand, the toner needs to have a positive or negative charge depending on the charge polarity of the electrostatic latent image to be developed. For this reason, it is generally known to add a dye, a pigment or a charge control agent. Have been. Among them, as the positive charge control agent, quaternary ammonium salts and their lake pigments, polymers having a tertiary amino group or a quaternary ammonium salt in the side chain, triphenylmethane dyes and these lake pigments,
Modified products such as nigrosine and fatty acid metal salts are known.

However, with these conventional positive charge control agents,
Even if a sufficient amount of charge is not given to the toner, or even if a sufficient amount of charge is given to the toner, the toner is affected by other toner constituent materials, and excessive toner frictional charging or uneven charging may cause a blotch. This tends to cause an increase in toner cohesiveness, and a deterioration in development characteristics such as a decrease in image density and fog. This tendency is particularly remarkable in a positive toner having an acid value. Further, there is a problem of sleeve contamination which occurs when the charge control agent is missing from the toner and adheres to the surface of the sleeve as the toner carrier.

On the other hand, when the toner is brought into contact with the sleeve, which is a toner carrier, and frictionally charged, there is a problem of how to stably and efficiently maintain proper charging for a long period of time.

As a sleeve in an image forming apparatus using electrophotography, for example, a metal, an alloy thereof, or a compound thereof is molded into a cylindrical shape, and the surface thereof is formed to a predetermined surface roughness by electrolysis, blasting, sanding, or the like. What was processed as mentioned above is used. As general sleeve base materials, stainless steel, aluminum and nickel proposed in Japanese Patent Application Laid-Open No. 57-66455 are widely used.

However, it is difficult to adjust the amount of toner charge when the positive toner is charged by using these sleeves. For example, when stainless steel is used as the sleeve base material, the charging power is strong. The toner existing near the surface of the sleeve has a very high electric charge, and is strongly attracted to the surface of the sleeve by the mirroring power, thereby forming an immobile layer. As a result, the chance of friction between the toner and the sleeve is reduced, and suitable charging is hindered. As a result, blotching due to uneven charging or excessive charging of the toner is likely to occur, and the developing characteristics naturally deteriorate.

Further, when aluminum is used as the sleeve base material, although the ability to impart a charge to the positive toner is high, the durability is poor due to the softness of the material, and image deterioration due to surface abrasion tends to occur. In order to provide wear resistance, there is a technology to coat or plate metal on the surface of the aluminum substrate.However, the durability is improved by improving the hardness of the sleeve surface, but the charging of positive toner is higher than that of stainless steel. In many cases, the toner had low ability, and was likely to cause poor charging of the toner.

Similarly, when the sleeve base material is provided with a resin layer on the surface thereof, the durability is good, but the control of the charging property to the toner is restricted, and the application range to the negative charging is limited. Although it is wide, when it is applied to positive charge application, it is not possible to provide an appropriate charge applying ability, and particularly when the binder resin has an acid value, it is difficult to apply the charge. It is the current situation.

[0027]

SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming method which solves the above-mentioned problems. That is, an object of the present invention is to provide a uniform toner coat layer having excellent anti-offset properties and having no blotch on a toner carrier, and a stable and high image density and low fog with high durability can be obtained. An object of the present invention is to provide an image forming method capable of stably obtaining good image characteristics.

[0028]

According to the present invention, a positively chargeable toner containing at least a binder resin, a colorant, and a charge control agent is conveyed by a toner carrier having a resin layer on a metal substrate, and the toner is electrostatically charged. In an image forming method in which a positively chargeable toner is transferred from a toner carrier to develop an electrostatic latent image formed on a latent image holding member and developed to form a toner image, the binder resin is a polymer component Has an acid value of 0.5 mgKOH / g to 50 mgKOH / g, and the charge control agent has an imidazole derivative represented by the following general formula (1).

[0029]

Embedded image (R ₁ and R ₂ in the general formula (1) are a hydrogen atom, an alkyl group having 1 to 35 carbon atoms (which may be branched),
Represents an aryl group or an aralkyl group, which may be the same or different, may have a substituent, and R ₃ is an alkyl group having 1 to 35 carbon atoms (which may be branched) , An aryl group or an aralkyl group. )

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventor has set the acid value of the entire polymer component of a binder resin for toner to 0.5 mgKOH / g to 5 mgKOH / g.
By using 0 mgKOH / g and using a specific imidazole derivative described later as a charge control agent, it has been found that good offset resistance can be realized without impairing the charging characteristics and powder characteristics as a positive toner. Further, by using a developing sleeve for forming a resin layer on a metal substrate as a developing sleeve for frictionally charging the toner, excellent charging characteristics which have not been obtained in the past can be obtained. , And as a result, it became clear that excellent development characteristics could be maintained.

The reason why the effect is achieved in the present invention will be described below.

First, when an imidazole derivative represented by the general formula (1) is used as a charge control agent in a toner having an acid value, uniform triboelectricity is excellent, and sufficient triboelectricity is obtained even in a positive toner having an acid value. It has been found that it has the ability, while having the excellent property of suppressing excessive charging. The mechanism of suppressing the excessive charging of the toner has not been elucidated at the present time, but it is considered that some interaction occurs between the resin having an acid group and the imidazole derivative. In any case, by suppressing excessive charging of the toner, it is possible to prevent the occurrence of blotches and an increase in toner cohesiveness.

The toner containing the imidazole derivative of the general formula (1) used in the present invention has a small variation in charging characteristics even under a high or low humidity environment, can maintain stable developing characteristics, and has an acid group. Since there is little loss of the imidazole derivative from the resin-based toner, the occurrence of sleeve contamination can be suppressed.

Further, the toner used in the present invention has good triboelectric charging performance even when a general stainless steel, aluminum, or metal plating is used as the toner carrier material in the process of triboelectric charging with the toner carrier. As shown in the figure, it has been found that even in contact with a resin-coated toner carrier, which has conventionally been difficult to perform positive triboelectric charging, it exhibits much better positive charging ability.

This is due to the difference in chargeability between the toner and the material of each toner carrier. That is, regarding the charging ability of the toner containing the resin having an acid group and the imidazole derivative represented by the general formula (1) with the material of the toner carrier, the charging generated by contact with stainless steel, aluminum, metal plating, or the like. It was found that a larger amount of charge was generated when the metal substrate having a conductive resin layer (for example, a carbon black-dispersed resin layer) was in contact with the metal substrate than when the metal substrate had a conductive resin layer.

The acid value of the entire polymer component of the binder resin for toner used in the present invention is from 0.5 mgKOH / g to 50 mgKOH / g.
mgKOH / g, preferably 0.5 mgKOH / g.
g to 30 mgKOH / g, more preferably 0.1 mgKOH / g.
5 mgKOH / g to 20 mgKOH / g is good. If the acid value of the entire polymer component is less than 0.5 mgKOH / g, the toner adheres to the fixing roller member, causing fouling of the fixing roller, not exhibiting good offset resistance, and the imidazole derivative. Developing stability and sleeve contamination prevention effect due to interaction with 50
If it exceeds mgKOH / g, the negative chargeability of the binder resin for toner becomes strong, and the image density tends to decrease and fog tends to increase.

In the present invention, the acid value (JIS acid value) of the entire polymer component of the binder resin for toner is determined by the following method.

<Measurement of Acid Value> The basic operation is JIS K-0.
070. 1) The sample is used after removing additives other than the polymer component in advance, or the acid value and the content of the component other than the polymer are obtained in advance. 0.5 to 2.0 (g) of the crushed sample is precisely weighed, and the weight of the polymer component is defined as W (g). 2) The sample is placed in a 300 (ml) beaker, and 150 (ml) of a mixed solution of toluene / ethanol (4/1) is added and dissolved. 3) Titration using a 0.1N KOH ethanol solution using a potentiometric titrator (for example, a potentiometric titrator AT-400 manufactured by Kyoto Electronics Co., Ltd. (win wor)
kstation) and automatic titration using an ABP-410 motorized burette is available). 4) The amount of the KOH solution used at this time is defined as S (ml), a blank is measured at the same time, and the amount of the KOH solution used at this time is defined as B (ml). 5) Calculate the acid value by the following equation. f is a factor of KOH.

Acid value (mgKOH / g) = ｛(SB) ×
f × 5.61｝ / W

The monomers for adjusting the acid value of the polymer component of the present invention include, for example, acrylic acid, methacrylic acid, α
-Acrylic acid such as ethyl acrylic acid, crotonic acid, cinnamic acid, vinyl acetic acid, isocrotonic acid, angelic acid and its α- or β-alkyl derivatives, fumaric acid, maleic acid, citraconic acid, alkenyl succinic acid, itaconic acid, mesacon Acids, dimethyl maleic acid, unsaturated dicarboxylic acids such as dimethyl fumaric acid and monoester derivatives or anhydrides thereof, and such monomers alone,
Alternatively, a desired polymer can be produced by mixing and copolymerizing with another monomer. Among them, it is particularly preferable to use a monoester derivative of an unsaturated dicarboxylic acid for controlling the acid value.

More specifically, for example, monomethyl maleate, monoethyl maleate, monobutyl maleate, monooctyl maleate, monoallyl maleate,
Monoesters 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, Monoesters of alkenyldicarboxylic acids such as monoethyl n-butenylmalonate, monomethyl n-dodecenylglutarate, monobutyl n-butenyladipate, and the like are included.

The above-mentioned carboxyl group-containing monomer may be added in an amount of 0.1 to 20 parts by mass, preferably 0.2 to 15 parts by mass, based on 100 parts by mass of all the monomers constituting the binder resin.

The reason why the monoester monomer of dicarboxylic acid as described above is selected is that it is used in the form of an ester having a low solubility in an aqueous suspension and a high solubility in an organic solvent or another monomer. Is preferred.

In the present invention, the carboxylic acid groups and carboxylic acid ester sites in the copolymer obtained by the above method can be saponified by alkali treatment. That is, a carboxylic acid group or a carboxylic acid ester site may be changed to a polar functional group by reacting with a cation component of an alkali.

This alkali treatment may be carried out after the production of the binder resin, by introducing it as an aqueous solution into the solvent used during the polymerization and stirring. Examples of the alkali that can be used in the present invention include Na, K, Ca, Li, Mg, and Ba.
Hydroxides of alkali metals and alkaline earth metals such as;
There are hydroxides of transition metals such as Zn, Ag, Pb, and Ni; hydroxides of quaternary ammonium salts such as ammonium salts, alkylammonium salts, and pyridium salts. Particularly preferred examples include NaOH and KOH. .

In the present invention, the saponification reaction does not need to be carried out over all of the carboxylic acid groups and carboxylic acid ester sites in the copolymer. I just need to change.

The amount of the alkali used in the saponification reaction is difficult to determine unconditionally depending on the type of the polar group in the binder resin, the dispersion method, the type of the constituent monomers, and the like. What is necessary is just 02-5 times equivalent. When the amount is less than 0.02 equivalent, the saponification reaction is not sufficient, and the number of polar functional groups generated by the reaction is reduced, and as a result, the subsequent crosslinking reaction becomes insufficient. On the other hand, when the amount exceeds 5 times equivalent, the functional group such as a carboxylic acid ester site is adversely affected by hydrolysis of the ester, generation of a salt by a saponification reaction, and the like.

When an alkali treatment of 0.02 to 5 times equivalent of the acid value is applied, the residual cation concentration after the treatment is 5 to 1
It is contained between 000 ppm and can be preferably used to regulate the amount of alkali.

The resin composition according to the present invention has a glass transition temperature (Tg) of 45 to 80 ° C., preferably 50 to 70 ° C. from the viewpoint of storage stability. Causes deterioration of the toner and offset at the time of fixing. If the Tg exceeds 80 ° C., the fixability tends to decrease.

The resin composition according to the present invention preferably has a low molecular weight polymer and a high molecular weight polymer.

As a method for synthesizing the high molecular weight polymer of the resin composition according to the present invention, a solution polymerization method, an emulsion polymerization method, or a suspension polymerization method can be used as a polymerization method that can be used in the present invention.

Among them, the emulsion polymerization method is a method in which a monomer (monomer) almost insoluble in water is dispersed in an aqueous phase as small particles with an emulsifier, and polymerization is carried out using a water-soluble polymerization initiator. . In this method, the reaction heat can be easily adjusted, and the phase in which the polymerization is performed (oil phase composed of a polymer and a monomer)
And the aqueous phase are separate, so that the termination reaction rate is low, resulting in a high polymerization rate and a high degree of polymerization. Further, due to the relatively simple polymerization process and the fact that the polymerization product is fine particles, in the production of toner,
There is an advantage as a method for producing a binder resin for a toner because it is easy to mix with a colorant, a charge control agent and other additives.

However, the resulting polymer tends to be impure due to the added emulsifier, and an operation such as salting out is required to take out the polymer. To avoid this inconvenience, suspension polymerization is convenient.

In the suspension polymerization, 100 parts by mass or less of the monomer (preferably 1 part by mass) is added to 100 parts by mass of the aqueous solvent.
(0 to 90 parts by mass). Examples of usable dispersants include polyvinyl alcohol, partially saponified polyvinyl alcohol, and calcium phosphate, and are generally used in an amount of 0.05 to 1 part by mass based on 100 parts by mass of the aqueous solvent. The polymerization temperature is suitably from 50 to 95 ° C., but is appropriately selected depending on the initiator used and the intended polymer.

In order to achieve the object of the present invention, the high molecular weight polymer of the resin composition used in the present invention is used alone or in combination with a monofunctional polymerization initiator as exemplified below. It is preferable to generate it.

Specific examples of the polyfunctional polymerization initiator having a polyfunctional structure include 1,1-di-t-butylperoxy-
3,3,5-trimethylcyclohexane, 1,3-bis- (t-butylperoxyisopropyl) benzene,
2,5-dimethyl-2,5- (t-butylperoxy)
Hexane, 2,5-dimethyl-2,5-di- (t-butylperoxy) hexane, tris- (t-butylperoxy) triazine, 1,1-di-t-butylperoxycyclohexane, 2,2 -Di-t-butylperoxybutane, 4,4-di-t-butylperoxyvaleric acid-n-butyl ester, di-t-butylperoxyhexahydroterephthalate, di-t-butylperoxyazelate , Di-t-butylperoxytrimethyladipate, 2,2-bis- (4,4-di-t-butylperoxycyclohexyl) propane, 2,2-t-
Polyfunctional polymerization initiator having a functional group having a polymerization initiation function such as two or more peroxide groups in one molecule such as butylperoxyoctane and various polymer oxides,
And a functional group having a polymerization initiating function such as a peroxide group in one molecule such as diallyl peroxydicarbonate, t-butyl peroxymaleic acid, t-butyl peroxyallyl carbonate and t-butyl peroxyisopropyl fumarate And a polyfunctional polymerization initiator having both a polymerizable unsaturated group.

Of these, more preferred are 1,1
-Di-tert-butylperoxy-3,3,5-trimethylcyclohexane, 1,1-di-tert-butylperoxycyclohexane, di-tert-butylperoxyhexahydroterephthalate, di-tert-butylperoxyase And 2,2-bis- (4,4-di-t-butylperoxycyclohexyl) propane, and t-butylperoxyallyl carbonate.

These polyfunctional polymerization initiators are preferably used in combination with a monofunctional polymerization initiator in order to satisfy various performances required as a binder for a toner.
In particular, it is preferable to use the polyfunctional polymerization initiator together with a polymerization initiator having a half life of 10 hours lower than the decomposition temperature for obtaining a half life of 10 hours.

Specifically, benzoyl peroxide,
1,1-di (t-butylperoxy) -3,3,5-trimethylcyclohexane, n-butyl-4,4-di (t
-Butylperoxy) valerate, dicumyl peroxide, α, α'-bis (t-butylperoxydiisopropyl) benzene, t-butylperoxycumene, di-t
Organic peroxides such as -butyl peroxide; and azo and diazo compounds such as azobisisobutyronitrile and diazoaminoazobenzene.

These monofunctional polymerization initiators may be added to the monomer at the same time as the polyfunctional polymerization initiator. However, in order to maintain the efficiency of the polyfunctional polymerization initiator properly,
It is preferable to add the compound after the half-life of the polyfunctional polymerization initiator has passed in the polymerization step.

These initiators are preferably used in an amount of 0.05 to 2 parts by mass based on 100 parts by mass of the monomer from the viewpoint of efficiency.

The high molecular weight polymer is preferably crosslinked with a crosslinking monomer as exemplified below in order to achieve the object of the present invention.

As the crosslinkable monomer, a monomer having two or more polymerizable double bonds is mainly used. Specific examples include aromatic divinyl compounds (eg, divinylbenzene, divinylnaphthalene, etc.); diacrylate compounds linked by an alkyl chain (eg, ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4 -Butanediol diacrylate, 1,5-pentanediol diacrylate, 1,6
Hexanediol diacrylate, neopentyl glycol diacrylate, and acrylates of the above compounds replaced with methacrylate); diacrylate compounds linked by an alkyl chain containing an ether bond (for example, diethylene glycol diacrylate, triethylene glycol) Diacrylate, tetraethylene glycol diacrylate, polyethylene glycol # 400 diacrylate, polyethylene glycol # 600 diacrylate, dipropylene glycol diacrylate, and those obtained by replacing the acrylate of the above compound with methacrylate); Diacrylate compounds linked by a chain containing, for example, polyoxyethylene (2) -2,2-bis (4-hydroxyphenyl) propanediacryle DOO, polyoxyethylene (4) -
2,2-bis (4-hydroxyphenyl) propane diacrylate and those obtained by replacing the acrylates of the above compounds with methacrylates; further, polyester-type diacrylate compounds (for example, trade name MANDA (Nippon Kayaku)) ). As multifunctional crosslinking agents, pentaerythritol acrylate, trimethylolethane triacrylate, trimethylolpropane triacrylate, tetramethylolpropane triacrylate, tetramethylolmethanetetraacrylate, oligoester acrylate, and acrylates of the above compounds to methacrylate Alternatives; triallyl cyanurate, triallyl trimellitate; and the like.

These cross-linking agents can be used in combination with other monomer components 10
1 part by mass or less, preferably 0.00 part by mass with respect to 0 parts by mass.
It is preferable to use in the range of 1 to 0.05 parts by mass.

Among these crosslinkable monomers, those which are preferably used from the viewpoint of fixing property and offset resistance of the toner include an aromatic divinyl compound (particularly, divinylbenzene), and a chain containing an aromatic group and an ether bond. Diacrylate compounds.

On the other hand, as a method for synthesizing the low molecular weight polymer component of the binder resin according to the present invention, a known method can be used. However, in the bulk polymerization method, a polymer having a low molecular weight can be obtained by increasing the termination reaction rate by polymerizing at a high temperature, but there is a problem that the reaction is difficult to control. In this regard, in the solution polymerization method, a low molecular weight polymer can be easily obtained under mild conditions by utilizing the difference in chain transfer of radicals depending on the solvent, and by adjusting the amount of the initiator and the reaction temperature, It is preferable to obtain a low molecular weight compound in the resin composition used in the present invention. In particular, a solution polymerization method under a pressurized condition is also preferable from the viewpoint of minimizing the amount of the initiator used and minimizing the influence of the residual initiator.

The monomer for obtaining the high molecular weight polymer component and the monomer for obtaining the low molecular weight polymer component include:
Examples 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 derivatives such as p-tert-butylstyrene, p-n-hexylstyrene, p-n-octylstyrene, p-n-nonylstyrene, p-n-decylstyrene, p-n-dodecylstyrene; ethylene, propylene , Butylene, ethylenically unsaturated monoolefins such as isobutylene; unsaturated polyenes such as butadiene and isoprene; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide, and vinyl fluoride; vinyl acetate, vinyl propionate, Vinyl esters such as vinyl benzoate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, (2-ethylhexyl) methacrylate, methacryl Stearyl acid Α-methylene aliphatic monocarboxylic esters such as phenyl methacrylate, dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, acryl Acrylic esters such as n-octyl acid, dodecyl acrylate, acrylic acid (2-ethylhexyl), stearyl acrylate, acrylic acid (2-chloroethyl), phenyl acrylate; vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether Vinyl ethers such as; vinyl methyl ketone;
Vinyl ketones such as vinyl hexyl ketone and methyl isopropenyl ketone; N-vinyl compounds such as N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone; vinyl naphthalenes;
Acrylic acid derivatives such as acrylonitrile, methacrylonitrile, and acrylamide or methacrylic acid derivatives are exemplified. These vinyl monomers are used alone or as a mixture of two or more monomers.

Among these, a combination of monomers that will result in a styrene-based copolymer and a styrene-acrylic copolymer is preferred.

It is preferable that both the low-molecular-weight polymer component and the high-molecular-weight polymer component contain at least 65 parts by mass of a styrene-based polymer component or a styrene-based copolymer component from the viewpoint of miscibility.

As a method for producing the binder resin composition, a high molecular weight polymer and a low molecular weight polymer are separately synthesized by a solution polymerization method, then mixed in a solution state, and then a solvent blending method is performed. , Melt-kneading with an extruder, etc., dissolved in the monomers constituting the high-molecular-weight polymer obtained by dissolving the low-molecular-weight polymer obtained by the solution polymerization method and the like, performing suspension polymerization, washing and drying, A two-stage polymerization method for obtaining a resin composition is also included. However, the dry blending method has problems in uniform dispersion and compatibility. Although the two-stage polymerization method has many advantages in uniform dispersibility, it is difficult to increase the low molecular weight component to a high molecular weight component or more, and in the presence of a low molecular weight polymer component, a high molecular weight polymer having a large molecular weight is used. Not only is the synthesis of coalescence difficult,
There is a problem that an unnecessary low molecular weight polymer is by-produced.
Therefore, the solution blending method with less adverse effects as described above is most preferable. Further, as a method for introducing a predetermined acid value into the low molecular weight polymer component, a solution polymerization in which the acid value can be easily set as compared with an aqueous polymerization method is preferable.

As the binder resin used in the toner of the present invention, the following polymers can also be used.

For example, homopolymers of styrene such as polystyrene, poly-p-chlorostyrene and polyvinyltoluene and their substituted products; styrene-p-chlorostyrene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene Copolymer, styrene-acrylate copolymer, styrene-methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-
Styrene such as vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer Copolymers: polyvinyl chloride, phenolic resin, natural modified phenolic resin, natural resin modified maleic acid resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester resin, polyurethane, polyamide resin, furan resin, epoxy resin , Xylene resin, polyvinyl butyral, terpene resin, coumarone indene resin, petroleum resin and the like can be used. Preferred binder resins include styrene copolymers and polyester resins. It is also possible to obtain an acid value by using a polyester resin.

Next, the composition of the polyester resin will be described.

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, bisphenol represented by the formula (A) and derivatives thereof;

[0076]

Embedded image (Wherein R is an ethylene or propylene group, x,
y is an integer of 0 or more, and the average value of x + y is 0 to 10. ).

Diols represented by the formula (B):

[0078]

Embedded image Where x 'and y' are integers of 0 or more, and x '
The average value of + y 'is 0 to 10. ).

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

It is preferable to use a trivalent or higher valent alcohol component and a trivalent or higher valent acid component, which also function as a crosslinking component.

The trihydric or higher polyhydric alcohol component includes
For example, sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol,
1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,
3,5-trihydroxybenzene and the like.

The trivalent or higher polycarboxylic acid component in the present invention includes, for example, trimellitic acid, pyromellitic acid, 1,2,4-benzenetricarboxylic acid,
2,5-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,2
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;

[0083]

Embedded image (Wherein X is an alkylene group or alkenylene group having 1 to 30 carbon atoms having at least one side chain having 1 or more carbon atoms), such as tetracarboxylic acids, and anhydrides and lower alkyl esters thereof. And polyvalent carboxylic acids 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%.

It is also preferable that the content of the trivalent or higher polyvalent component is 1 to 60 mol% of all the components.

The polyester resin can also be obtained by a generally known condensation polymerization.

In the toner according to the present invention, in addition to the above-mentioned binder resin component, the following compounds may be contained at a ratio smaller than the content of the binder resin component. For example, silicone resin, polyurethane, polyamide, epoxy resin, polyvinyl butyral, rosin, modified rosin, terpene resin,
Phenol resins, copolymers of two or more α-olefins, and the like are included.

In the present invention, the following waxes are preferably contained in order to impart releasability to the toner. A wax having a melting point of 70 to 165 ° C. and a melt viscosity at 160 ° C. of 1000 mPa · s or less. Specific examples thereof include paraffin wax, microcrystalline wax, Fischer-Tropsch wax, montan wax, ethylene, propylene, butene-1, Pentene-1, hexene-1, heptene-1, octene-
Homopolymers of linear α-olefins such as 1, nonene-1 and decene-1, branched α-olefins having a branched portion at the terminal, and olefins having different positions of unsaturated groups, or copolymers thereof. Polymers.

Further, a modified wax obtained by forming a block copolymer with a vinyl monomer or by performing a graft modification may be used.

The amount of the wax is preferably 0.5 to 10 parts by mass, more preferably 1 to 8 parts by mass, per 100 parts by mass of the binder resin.
Incidentally, two or more kinds of waxes may be added in combination.

These waxes are used in the production of toner.
It can also be added and mixed in the polymer component in advance.
In such a case, it is preferable that the wax and the high molecular weight polymer are preliminarily dissolved in a solvent and then mixed with a low molecular weight polymer solution at the time of preparing the polymer component. As a result, phase separation in a micro region is moderated, re-aggregation of high molecular weight components is suppressed, and a good dispersion state with a low molecular weight polymer can be obtained.

The solid concentration of the polymer solution is determined by the dispersion efficiency,
In consideration of prevention of deterioration of the resin at the time of stirring, operability, etc., 5 to 70
Preferably, the pre-solution of the high molecular weight polymer component and the wax has a solid concentration of 5 to 60% by mass or less, and the low molecular weight polymer solution has a solid concentration of 5 to 70% by mass or less.

The method of dissolving or dispersing the high molecular weight polymer component and the wax is performed by stirring and mixing, and the stirring is preferably performed in a batch system or a continuous system.

In the method of mixing the low molecular weight polymer solution, it is preferable to add 10 to 1000 parts by weight of the low molecular weight polymer solution to 100 parts by weight of the solid content of the preliminary solution and perform stirring and mixing. In this case, a batch type or a continuous type may be used.

Examples of the organic solvent used for mixing the solution of the resin composition according to the present invention include benzene, toluene, xylene, Solvent Naphtha No. 1, Solvent Naphtha No. 2
No. 3, Solvent Naphtha 3, cyclohexane, ethylbenzene, Solvesso 100, Solvesso 150, hydrocarbon solvents such as mineral spirits; methanol, ethanol, iso-propyl alcohol, n-butyl alcohol, sec-butyl alcohol, iso-butyl alcohol, Alcohol solvents such as amyl alcohol and cyclohexanol; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; ester solvents such as ethyl acetate, n-butyl acetate and cellosolve acetate; methyl cellosolve, ethyl cellosolve, butyl cellosolve; Examples thereof include ether solvents such as methyl carbitol. Among these, aromatic solvents, ketone solvents or ester solvents are preferred. They may be used in combination.

The method of removing the organic solvent is preferably a method of heating the organic solvent solution of the polymer, removing 10 to 80% by mass of the organic solvent under normal pressure, and removing the remaining solvent under reduced pressure. At this time, the organic solvent solution is preferably maintained at a temperature within the range of 200 ° C. from the boiling point of the organic solvent used. Below the boiling point of the organic solvent, not only is the efficiency at the time of solvent distillation low, but also unnecessary shearing force is applied to the polymer in the organic solvent, and the redispersion of each constituent polymer is promoted, and in a micro state, May cause phase separation. On the other hand, when the temperature is higher than 200 ° C., the polymer is depolymerized, an oligomer is generated by molecular cleavage, and impurities are mixed into the resin composition, which is not preferable.

Next, in the imidazole derivative represented by the following general formula (1) used as the charge control agent of the present invention, R ₁ and R ₂ in the general formula (1) represent a hydrogen atom and a carbon atom having 1 carbon atom. To 35 alkyl groups (which may be branched), aryl groups, and aralkyl groups, which may be the same or different, and may each have a substituent. Any one of R ₁ , R ₂ and R ₃ has 3 carbon atoms;
If it exceeds 5, the melting point of the imidazole derivative itself decreases, so that the melt viscosity of the imidazole derivative decreases in the melt-kneading step during toner production, making it difficult to uniformly disperse the imidazole derivative in the binder resin. Image degradation is likely to occur, and the binder resin may be limited.

[0098]

Embedded image

In the present invention, the imidazole derivative represented by the general formula (1) is used in an amount of 0.01 to 20.0 parts by mass, preferably 0.1 to 10 parts by mass, per 100 parts by mass of the binder resin.
0 parts by mass, more preferably 0.5 to 5.0 parts by mass is added. When the addition amount is less than 0.01 parts by mass, the toner cannot have a sufficient charge amount, and the effect of adding the imidazole derivative does not appear. On the other hand, when the addition amount is more than 20.0 parts by mass, excessive addition results in poor dispersion in the toner, resulting in agglomerates or uneven presence of the imidazole derivative per individual toner particle. This is not preferred.

Further, the imidazole derivative used in the present invention can be used in combination with a conventionally known charge control agent.

The imidazole derivative used in the present invention is synthesized as follows. Using methanol as a solvent, an imidazole compound represented by the following general formula (2-1) is reacted with acrylonitrile to obtain a compound represented by the following general formula (2-
The compound of 2) is obtained. This compound is synthesized by reacting with dicyandiamide.

[0102]

Embedded image This synthesis method does not limit the imidazole derivative used in the present invention at all. Examples of the imidazole derivative used in the present invention are shown below, but these are representative examples in consideration of ease of handling, and do not limit the toner of the present invention at all.

[0103]

Embedded image

[0104]

Embedded image

[0105]

Embedded image

[0106]

Embedded image

As the colorant that can be used in the toner of the present invention, any suitable pigment or dye can be used. For example, as pigments, carbon black, aniline black, acetylene black, naphthol yellow, hansa yellow, rhodamine lake, alizarin lake, bengara,
Examples include phthalocyanine blue and indanthrene blue. These are used in an amount necessary to maintain the optical density of the fixed image, and are used in an amount of 0.1 to 100 parts by mass of the binder resin.
An addition amount of 20 parts by mass, preferably 0.2 to 10 parts by mass is good. A dye is further used for the same purpose. For example, there are azo dyes, anthraquinone dyes, xanthene dyes, and methine dyes, and 0.1 to 20 parts by mass, preferably 0.3 to 10 parts by mass, per 100 parts by mass of the binder resin is good. .

Further, in the toner of the present invention, a magnetic substance can be used as a colorant and used as a magnetic toner.

The magnetic material used in the present invention includes iron oxides such as magnetite, maghemite and ferrite;
Metals such as cobalt and nickel or these metals and aluminum, cobalt, copper, lead, magnesium,
Alloys of metals such as tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium and mixtures thereof are used, and those containing silicon elements on the surface or inside of the magnetic material are used. preferable.

As a result of intensive studies by the present inventors, the inclusion of the silicon element in the magnetic substance makes the particle size distribution of the magnetic substance uniform, and the dispersion of the magnetic substance in the toner is smaller than that when the silicon element is not contained. It became clear that it was several steps better. Further, when a magnetic material containing a silicon element is contained in the toner, even in a toner having an average particle diameter of 10 μm or less, charging uniformity is improved, toner cohesion can be suppressed, and fluidity of the toner is improved. The triboelectric charge is improved. As a result, it was found that the initial image density was stable and the image fog was suppressed to a level at which there was almost no problem.

The content of the silicon element contained in the magnetic material is preferably 0.05 to 10% by mass based on the magnetic material. It is more preferably 0.1 to 7% by mass, and desirably 0.2 to 5% by mass. If the content of the silicon element in the magnetic substance is less than 0.05% by mass, the effect of adding the silicon element cannot be obtained, and the triboelectric charge amount of the toner tends to be nonuniform, and image fog increases. When the content is more than 10% by mass, the image fog is improved, but the surface of the toner carrier is contaminated, the image density is reduced, and ghosts are easily generated.

In the present invention, the amount of silicon element in the magnetic substance is determined by performing X-ray fluorescence analysis using a fluorescent X-ray analyzer SYSTEM3080 (manufactured by Rigaku Corporation) in accordance with JIS K0119 “General rules for X-ray fluorescence analysis”. Was measured by

The shape of the magnetic material used in the present invention may be hexahedron, octahedron, decahedron, dodecahedron, tetrahedron, or a polyhedron having more planes, needles, scales, spheres, and irregular shapes. Are used. Among them, a polyhedron is preferably used. In the case of a magnetic material having a polyhedral shape, it is possible to physically prevent the magnetic material from detaching from the toner particles from the shape.

In the present invention, the magnetic substance used for the toner is
BET specific surface area by nitrogen gas adsorption method is 1 to 40 m ²
/ G, preferably ² to 30 m ² / g, more preferably 3
２０20 m ² / g is good. As a measuring method, according to the BET method, nitrogen gas is adsorbed on the sample surface using a specific surface area measuring device: Autosoap 1 (manufactured by Yuasa Ionics), and B
The specific surface area is calculated using the ET multipoint method.

The saturation magnetization of the magnetic material is 79
In a magnetic field of 5.8 kA / m, 5-200 Am ² /
kg, preferably in the range of 10 to 150 Am ² / kg.

Further, the residual magnetization of the magnetic material is 79
In a magnetic field of 5.8 kA / m, 1 to 100 Am ² /
kg, preferably in the range of 1 to 70 Am ² / kg.

The average particle size of the magnetic material is 0.1.
It is preferably from 0.5 to 1.0 μm, more preferably from 0.1 to 1.0 μm.
It is 0.6 μm, particularly preferably 0.1 to 0.4 μm.

In the present invention, the amount of the magnetic substance contained in the toner is from 10 to 200 parts by mass, preferably from 20 to 170 parts by mass, more preferably from 30 to 150 parts by mass, per 100 parts by mass of the binder resin.

In the present invention, the shape of the magnetic material is that observed with a transmission electron microscope and a scanning electron microscope.

The magnetic properties of the magnetic material are values measured under an external magnetic field of 795.8 kA / m using a “vibrating sample magnetometer VSM-3S-15” (manufactured by Toei Kogyo Co., Ltd.).

In the toner of the present invention, charging stability,
In order to improve developability, fluidity and durability, it is preferable to add silica fine powder.

[0122] Silica fine powder used in the present invention has a specific surface area by the BET method by nitrogen adsorption 30 m ² / g or more, particularly in the range of 50 to 400 m ² / g give good results. It is preferable to use 0.01 to 8 parts by mass, preferably 0.1 to 5 parts by mass, of silica fine powder with respect to 100 parts by mass of the toner.

The silica fine powder used in the present invention may be used, if necessary, for the purpose of hydrophobicity, charge control, etc., with silicone varnish, various modified silicone varnishes, silicone oil, various modified silicone oils, silane coupling agents, It is also preferable that the treatment is performed with a treating agent such as a silane compound having a functional group or another organosilicon compound, or in combination with various treating agents.

[0124] Other external additives may be added to the toner of the present invention as needed.

For example, there are resin fine particles and inorganic fine particles which function as a charge auxiliary agent, a conductivity-imparting agent, a fluidity-imparting agent, an anti-caking agent, a releasing agent at the time of fixing with a heat roller, a lubricant, an abrasive and the like.

For example, examples of the lubricant include Teflon powder, zinc stearate powder, polyvinylidene fluoride powder and the like, and among them, polyvinylidene fluoride powder is preferable. Examples of the polishing agent include cerium oxide powder, silicon carbide powder, and strontium titanate powder, and among them, strontium titanate powder is preferable. Examples of the fluidity-imparting agent include a titanium oxide powder and an aluminum oxide powder, and among them, a hydrophobic agent is preferable. Examples of the conductivity-imparting agent include carbon black powder, zinc oxide powder, antimony oxide powder, and tin oxide powder. Still further, a small amount of white fine particles and black fine particles of opposite polarity can be used as a developing property improver.

To prepare the toner of the present invention, a binder resin, a colorant, an imidazole derivative and, if necessary, a magnetic substance, a wax, a metal salt or metal complex, a pigment or a dye, and other additives are added to Henschel. After sufficiently mixing with a mixer such as a mixer or a ball mill, the mixture is melt-kneaded using a hot kneader such as a heating roll, a kneader, or an extruder, and then cooled and solidified, then pulverized and classified, and further, if necessary, added as desired. The agent is sufficiently mixed by a mixer such as a Henschel mixer to obtain the toner of the present invention.

Next, a schematic diagram of a sleeve which is a toner carrier used in the image forming method of the present invention will be described with reference to FIG.

The sleeve has a cylindrical substrate and a coating layer (resin layer) covering the surface of the substrate. The resin layer 1 contains a binder resin 4, and in some cases, a conductive substance 2, a filler 3, a solid lubricant 5, and the like, and is coated on a cylindrical substrate 6. When the conductive material 2 is contained, the conductive resin layer 1 has conductivity, so that excessive charging of the toner can be prevented. When the filler 3 is contained, abrasion of the resin layer 1 by the toner is prevented, and further, charging of the toner can be suitably controlled by the charge imparting property of the filler 3.
When the solid lubricant 5 is contained, the releasability of the toner from the sleeve is improved, and as a result, the fusion of the toner onto the sleeve can be prevented.

When a conductive material is contained in the resin layer, the volume resistance of the resin layer is 10 ⁶ Ω · cm or less, preferably 1 Ω · cm or less.
It is preferably not more than 0 ³ Ω · cm. If the volume resistance of the resin layer exceeds 10 ⁶ Ω · cm, toner charge-up is likely to occur, which tends to cause blotches and deterioration of development characteristics.

The surface roughness of the resin layer is preferably in the range of 0.2 to 3.5 μm in JIS center line average roughness (Ra). If Ra is less than 0.2 μm, the charge amount of the toner in the vicinity of the sleeve becomes too high, the toner is attracted to the sleeve by the mirroring power, new toner cannot be charged by the sleeve, and the developing property is insufficient. Become.
When Ra exceeds 3.5 μm, the toner coat amount on the sleeve is excessively increased and the toner cannot obtain a sufficient charge amount.
In addition, the charging becomes non-uniform, which causes a reduction in image density and uneven density.

Next, each material constituting the resin layer 1 will be described.

In FIG. 1, the conductive substance 2 includes, for example, metal powders such as aluminum, copper, nickel and silver; metal oxides such as antimony oxide, indium oxide and tin oxide; carbon fibers, carbon black, graphite and the like. And carbon allotropes. Among them, carbon black is particularly excellent in electric conductivity, and is preferably used because it can be filled with a polymer material to impart conductivity, or by controlling the amount of addition, a certain degree of conductivity can be obtained. The carbon black used in the present invention has a number average particle diameter of 1 μm or less, preferably 0.01 μm to 0.1 μm.
It is preferably 8 μm. If the number average particle size of the carbon black exceeds 1 μm, it becomes difficult to control the volume resistance of the resin layer, which is not preferable.

The amount of the conductive substance used is as follows.
The amount is 0.1 to 300 parts by mass, preferably 1 to 100 parts by mass with respect to 00 parts by mass.

As the filler 3, a conventionally known negative charge control agent for toner or a positive charge control agent for toner may be added. Other substances such as alumina, asbestos, glass fiber, calcium carbonate, magnesium carbonate, barium carbonate, barium sulfate, silica,
Inorganic compounds such as calcium silicate; phenolic resin, epoxy resin, melamine resin, silicone resin, PMM
A, methacrylate terpolymer (for example, polystyrene / n-butyl methacrylate / silane terpolymer), styrene-butadiene copolymer, polycaprolactone; nitrogen-containing compounds such as polycaprolactam, polyvinylpyridine, polyamide; polyvinylidene fluoride, poly (vinylidene fluoride) Advanced such as vinyl chloride, polytetrafluoroethylene, polytetrachlorofluoroethylene, perfluoroalkoxylated ethylene, polytetrafluoroalkoxyethylene, fluorinated ethylene propylene-polytetrafluoroethylene copolymer, trifluorochloroethylene-vinyl chloride copolymer Halogenated polymer; and polycarbonate, polyester and the like. Among them, silica and alumina are preferably used because they have their own hardness and charge controllability to the toner.

The amount of the filler used is 100
It is preferably 0.1 to 500 parts by mass, more preferably 1 to 200 parts by mass with respect to parts by mass.

Examples of the solid lubricant 5 include molybdenum disulfide, boron nitride, graphite, graphite fluoride, silver-niobium selenide, calcium chloride-graphite, and talc. Among these, graphite is preferably used because it has conductivity together with lubricity, and has a function of reducing toner having an excessively high charge and providing a charge amount suitable for development.

The amount of the solid lubricant used is as follows.
The amount is preferably from 0.1 to 300 parts by mass, more preferably from 1 to 150 parts by mass, per 100 parts by mass.

Examples of the binder resin 4 in which the conductive substance 2, the filler 3, and the solid lubricant 5 are dispersed include phenolic resins, epoxy resins, polyamide resins, polyester resins, polycarbonate resins, and polyolefin resins. ,
Known resins such as a silicone resin, a fluorine resin, a styrene resin, and an acrylic resin are used. Particularly, a thermosetting or photocurable resin is preferable.

In the present invention, the conductive material in the resin layer on the sleeve surface, the filler or the solid lubricant is preferably exposed to the surface, or the surface is smoothed to form a uniform uneven surface. For this reason, it is possible to impart more preferable performance by smoothing the surface by means such as polishing described below. In particular, it is effective for the vertical streak phenomenon that occurs in solid black and halftone images and the rise of the initial image density, and is particularly effective under high temperature and high humidity.

The operation of the present invention will be described with reference to FIG. In FIG. 2A, the coating layer (resin layer) 501 includes a solid lubricant 50.
2, conductive substance 503, filler 504, binder resin 505
And coated on the cylindrical substrate 506. This is polished with a belt-like abrasive material to which felt or abrasive grains are adhered, so that the surface unevenness of the sleeve can be uniformly finished as shown in FIG. 2 (B). As a result, only the toner that has been frictionally charged with the sleeve is conveyed to the developing area. Therefore, it is considered that the above effects can be obtained.

[0142] Even after the smoothing treatment as described above, the surface of the coat layer has a Ra of 0.1 in Ra according to JIS B0601.
It is preferable to maintain irregularities in the range of 2 to 3.5 μm, more preferably about 0.3 to 2.5 μm.
The reason is the same as above.

Next, a description will be given of a developing method in which the developing sleeve serving as the toner carrier of the present invention is incorporated.

In FIG. 3, an image carrier for carrying an electrostatic latent image formed by a known process, for example, an electrophotographic photosensitive drum 7, is rotated in the direction of arrow B. The developing sleeve 14 as a toner carrier carries the magnetic toner 10 as a one-component magnetic developer supplied from the hopper 9, and rotates in the direction indicated by an arrow A, thereby causing the developing sleeve 1 to rotate.
4 and the photosensitive drum 7, the magnetic toner 1
Convey 0. In the developing sleeve 14, the magnetic toner 1
The magnet 11 is arranged to magnetically attract and hold the “0” on the developing sleeve 14. The magnetic toner 10 obtains a triboelectric charge capable of developing the electrostatic latent image on the photosensitive drum 7 by friction with the developing sleeve 14.

In order to regulate the layer thickness of the magnetic toner 10 conveyed to the developing section D, a regulating blade 8 made of a ferromagnetic metal is moved from the surface of the developing sleeve 14 by about 200 to 300 μm.
It is hung from the hopper 9 so as to face the developing sleeve 14 with a gap width of m. Magnetic pole N of magnet 11
The magnetic lines of force from 1 concentrate on the blade 8 to form a thin layer of the magnetic toner 10 on the developing sleeve 14. As the blade 8, a non-magnetic blade can be used.

The thickness of the thin layer of the magnetic toner 10 formed on the developing sleeve 14 is preferably smaller than the minimum gap between the developing sleeve 14 and the photosensitive drum 7 in the developing section D. The present invention is particularly effective for a developing device of a type that develops an electrostatic latent image with such a thin toner layer, that is, a non-contact type developing device. However, in the developing section, the thickness of the toner layer is
The present invention can also be applied to a developing device having a thickness not less than the minimum gap between them, that is, a contact type developing device.

For the sake of simplicity, the following description will be made by taking a non-contact type developing device as an example.

A power supply 15 applies a developing bias voltage to the developing sleeve 14 in order to fly the magnetic toner 10 as a one-component magnetic developer carried on the developing sleeve 14. When a DC voltage is used as the developing bias voltage, a voltage having a value between the potential of the image portion of the electrostatic latent image (the region where the magnetic toner 10 is adhered and visualized) and the potential of the background portion is used. Preferably, it is applied to the sleeve 14.
On the other hand, an alternating bias voltage is applied to the developing sleeve 14 to increase the density of the developed image or improve the gradation.
An oscillating electric field whose direction is alternately reversed may be formed in the developing unit D. In this case, it is preferable to apply, to the developing sleeve 14, an alternating bias voltage on which a DC voltage component having a value between the potential of the image portion and the potential of the background portion is superimposed.

Further, in so-called regular development in which toner is adhered to a high potential portion of an electrostatic latent image having a high potential portion and a low potential portion to visualize the toner, a toner charged to a polarity opposite to the polarity of the electrostatic latent image is used. On the other hand, in so-called reversal development, in which toner is adhered to a low potential portion of an electrostatic latent image to visualize the toner, a toner charged to the same polarity as the polarity of the electrostatic latent image is used.
Note that the high potential and the low potential are expressed by absolute values. In any case, the magnetic toner 10 is applied to the developing sleeve 1
The electrostatic latent image is charged to a polarity for developing the electrostatic latent image by friction with the toner image 4.

FIG. 4 is a block diagram showing another embodiment of the present invention.

In the developing device shown in FIG. 4, as a member for regulating the layer thickness of the magnetic toner 10 on the developing sleeve 14, a material having rubber elasticity such as urethane rubber or silicone rubber, or a metal such as phosphor bronze or stainless steel is used. It is characterized in that an elastic plate 17 made of an elastic material or the like is used, and this elastic plate 17 is pressed against the developing sleeve 14. In such a developing device, a thinner toner layer can be formed on the developing sleeve 8. The other configuration of the developing device of FIG. 4 is basically the same as that of the developing device shown in FIG. 3. In FIG. 4, the same reference numerals as those shown in FIG. 3 denote the same members.

In the developing device shown in FIG. 4 in which the toner layer is formed on the developing sleeve 14 as described above, the toner is rubbed on the developing sleeve 14 by the elastic plate 17, so that the amount of triboelectric charge of the toner is large. Thus, the image density is improved. Such a developing device is used for a non-magnetic one-component toner.

Next, an example of an image forming method having a contact charging / transfer method used in the present invention will be described with reference to the schematic configuration diagram of FIG.

A rotary drum type photosensitive member 801 is rotated at a predetermined peripheral speed (process speed) clockwise in the drawing. Reference numeral 802 denotes a charging roller which is pressed against the surface of the photoconductor 801 with a pressing force, and is driven to rotate as the photoconductor 801 rotates. 803 denotes a charging bias current V ₂ for applying a voltage to the charging roller 802, the surface of the photosensitive member 801 is charged to a predetermined polarity and potential by a bias is applied to the charging roller 802. Next, image exposure 8
04 forms an electrostatic image, and the developing unit 805 sequentially visualizes the image as a toner image.

A bias V ₁ is applied to the developing sleeve constituting the developing unit 805 from the bias applying unit 813. The toner image formed on the latent image bearing member by development, contact transfer means transfer bias V ₃ applied 806
, And the toner image on the transfer material is heated and pressed by the heating and pressing means 811.
On the surface of the photoconductor 801 after the transfer of the toner image, adhered contaminants such as untransferred toner are cleaned by a cleaning device 809 having an elastic cleaning blade pressed against the photoconductor 801 in a counter direction.
The charge is eliminated by 0, and an image is repeatedly formed.

[0156]

EXAMPLES The present invention will be described in more detail with reference to specific examples, but the present invention is not limited to these examples.

(Synthesis Example of Binder Resin) <Resin Synthesis Example 1> 79.2 parts by mass of styrene 20.0 parts by mass of n-butyl acrylate 0.8 parts by mass of monobutyl malate 2,2′-azobis (2, 4-dimethylvaleronitrile) 0.2 parts by mass

The above raw materials were dropped into 200 parts by mass of heated xylene over 4 hours. Further, the polymerization was completed under reflux of xylene, and the solvent was distilled off under reduced pressure. The resin thus obtained is referred to as a resin a.

Resin a 30.0 parts by mass Styrene 56.0 parts by mass n-butyl acrylate 12.2 parts by mass Monobutyl maleate 1.4 parts by mass Divinylbenzene 0.4 parts by mass Di-tert-butyl peroxide 1. 0 parts by mass

The above raw materials were added dropwise to 200 parts by mass of heated xylene over 4 hours. Further, the polymerization was completed under xylene reflux, and the solvent was distilled off under reduced pressure. The resin thus obtained is referred to as resin A. The acid value of this resin A was 5.2 mgKOH / g and Tg = 60 ° C.

<Resin Synthesis Example 2> Styrene 79.0 parts by mass n-butyl acrylate 21.0 parts by mass 2,2-bis (4,4-di-tert-butyl peroxycyclohexyl) propane 0.3 parts by mass

The above raw materials were added dropwise to 200 parts by mass of heated xylene over 4 hours. Further, the polymerization was completed under xylene reflux to obtain a resin b.

Styrene 82.0 parts by mass n-butyl acrylate 17.0 parts by mass Monobutyl malate 1.0 part by mass Di-tert-butyl peroxide 1.0 part by mass

The above raw materials were added dropwise to 200 parts by mass of heated xylene over 4 hours. Further, the polymerization was completed under reflux of xylene to obtain a resin c. After mixing the solutions so that the mass ratio of the resin b to the resin c was 25:75, the solvent was distilled off under reduced pressure. The resin thus obtained is referred to as a resin B. The acid value of this resin B is 2.3 mgKOH /
g, Tg = 60 ° C.

<Resin Synthesis Example 3> Styrene 77.0 parts by mass n-butyl acrylate 20.0 parts by mass monobutyl maleate 3.0 parts by mass 2,2-bis (4,4-di-tert-butyl peroxy) Cyclohexyl) propane 0.3 parts by mass

The above raw materials were added dropwise to 200 parts by mass of heated xylene over 4 hours. Further, the polymerization was completed under reflux of xylene to obtain a resin d.

Styrene: 78.0 parts by mass n-butyl acrylate: 18.0 parts by mass Methacrylic acid: 4.0 parts by mass Di-tert-butyl peroxide: 1.0 part by mass

The above raw materials were added dropwise to 200 parts by mass of heated xylene over 4 hours. Further, the polymerization was completed under reflux of xylene to obtain a resin e. After mixing the solutions so that the mass ratio of resin d to resin e was 40:60, the solvent was distilled off under reduced pressure. The resin thus obtained is referred to as a resin C. The acid value of this resin C is 18.8 mgKOH
/ G, Tg = 60 ° C.

<Resin Synthesis Example 4> 74.0 parts by mass of styrene 22.0 parts by mass of butyl acrylate 3.5 parts by mass of acrylic acid 0.5 parts by mass of divinylbenzene 0.8 parts by mass of di-tert-butyl peroxide

The above raw materials were added dropwise to 200 parts by mass of heated xylene over 4 hours. Further, the polymerization was completed under reflux of xylene, and the solvent was distilled off under reduced pressure. The resin thus obtained is referred to as a resin D. The acid value of this resin D was 27.0 mgKOH / g, and Tg = 60 ° C.

<Synthesis Example 5> 73.0 parts by mass of styrene 22.0 parts by mass of butyl acrylate 4.5 parts by mass of acrylic acid 0.5 parts by mass of divinylbenzene 0.8 parts by mass of di-tert-butyl peroxide

The above raw materials were added dropwise to 200 parts by mass of heated xylene over 4 hours. Further, the polymerization was completed under reflux of xylene, and the solvent was distilled off under reduced pressure. The resin thus obtained is referred to as a resin E. The acid value of this resin E was 34.8 mgKOH / g, and Tg = 60 ° C.

<Resin Comparative Synthesis Example 1> Styrene 80.0 parts by mass n-butyl acrylate 20.0 parts by mass 2,2-bis (4,4-di-tert-butyl peroxycyclohexyl) propane 0.3 part by mass

The above raw materials were added dropwise to 200 parts by mass of heated xylene over 4 hours. Further, the polymerization was completed under reflux of xylene to obtain a resin f.

83.0 parts by mass of styrene 17.0 parts by mass of n-butyl acrylate 1.0 part by mass of di-tert-butyl peroxide

The above raw materials were dropped into 200 parts by mass of heated xylene over 4 hours. Further, the polymerization was completed under xylene reflux to obtain resin g. After mixing the solutions so that the mass ratio of the resin f to the resin g was 30:70, the solvent was distilled off under reduced pressure. The resin thus obtained is referred to as a resin F. The acid value of this resin F is 0.1 mgKOH /
g, Tg = 60 ° C.

<Resin Comparative Synthesis Example 2> 69.0 parts by mass of styrene 22.0 parts by mass of butyl acrylate 8.5 parts by mass of methacrylic acid 0.5 parts by mass of divinylbenzene 0.8 parts by mass of di-tert-butyl peroxide

The above raw materials were dropped into 200 parts by mass of heated xylene over 4 hours. Further, the polymerization was completed under reflux of xylene, and the solvent was distilled off under reduced pressure. The resin thus obtained is referred to as a resin G. The acid value of this resin G was 55.2 mgKOH / g, and Tg = 60 ° C.

<Developing Sleeve Production Example 1> Phenol resin intermediate 125 parts by mass Carbon black 5 parts by mass Crystalline graphite 45 parts by mass Methanol 41 parts by mass isopropyl alcohol 284 parts by mass Methanol solution of phenol resin intermediate in isopropyl alcohol (IPA) , Carbon black and crystalline graphite were added, and the mixture was dispersed by a sand mill using glass beads. Next, a resin layer was applied on the sleeve using this paint.

As the developing sleeve, the surface of a stainless steel cylindrical tube having an outer diameter of 20 mm and a wall thickness of 0.8 mm was polished to reduce the run-out of the cylindrical tube to 10 μm or less and the surface roughness to 4 μm or less in Rz notation. Was. The sleeve was set up vertically, rotated at a constant speed, masked at the upper and lower ends, and the coating material was applied while lowering the spray gun at a constant speed. Masking width at both ends of sleeve is 3m
m. After drying and curing at 160 ° C. for 20 minutes in a drying oven, a belt-shaped felt is rubbed against the surface of the resin-coated sleeve with a load of 4 kgf, and the surface is polished. Got a sleeve.

This resin layer has a thickness of 10 μm and a surface roughness R
a was 0.86 μm on average at 6 points, the volume resistance was 4 Ω · cm, and the pencil hardness was further measured to be 2H.
A magnet was inserted into this sleeve, and flanges were attached to both ends to obtain a developing sleeve 1.

<Developing Sleeve Production Example 2> Phenol resin intermediate 125 parts by mass Carbon black 5 parts by mass Crystalline graphite 45 parts by mass Surface treated silica fine powder 25 parts by mass (Dry silica having a specific surface area of about 130 m ² / g by BET) The fine powder was subjected to a surface treatment with methyltrimethoxysilane.) Methanol 58 parts by mass isopropyl alcohol 408 parts by mass The above materials were dispersed using a sand mill. The methanol solution of the phenol resin intermediate was diluted with a part of isopropyl alcohol (IPA), carbon black and crystalline graphite were added, and the mixture was dispersed by a sand mill using glass beads. Here, the above treated silica dispersed in the remaining IPA was further added as a filler, and the sand mill dispersion was further advanced.

Next, using this coating material, a resin layer was coated on the sleeve in the same manner as in Production Example 1 for a resin-coated developing sleeve, and then the surface was polished. The thickness of the conductive resin layer is 15 μm, and the surface roughness Ra is 1.08 on an average of 6 points.
μm, the volume resistance was 7 Ω · cm, and the pencil hardness was further measured to be 3H. A magnet was inserted into this sleeve, and flanges were attached to both ends to form a developing sleeve 2.

<Developing Sleeve Production Example 3> The paint used in the developing sleeve production example 1 was used.
The surface of an aluminum cylindrical tube having an outer diameter of 16 mm and a wall thickness of 0.8 mm was polished to make the cylindrical tube have a runout of 10 μm or less and a surface roughness of 4 μm or less in Rz. The sleeve was set up vertically, rotated at a constant speed, masked at the upper and lower ends, and the coating material was applied while lowering the spray gun at a constant speed. The masking width at both ends of the sleeve was set to 3 mm. This is placed in a drying oven for 16
After drying and hardening at 0 ° C. for 20 minutes, a belt-shaped felt was pressed against the surface of the resin-coated sleeve and rubbed with a load of 4 kgf, and the surface was polished to obtain a resin-coated sleeve having a uniform film thickness.

The resin layer had a thickness of 11 μm and a surface roughness R
a was 0.97 μm on average at 6 points, the volume resistance was 4 Ω · cm, and the pencil hardness was further measured to be 2H.
A flange was attached to both ends of this sleeve to form a developing sleeve 3.

<Developing Sleeve Comparative Manufacturing Example 1> As a developing sleeve, the surface of a stainless steel cylindrical tube having an outer diameter of 20 mm and a wall thickness of 0.8 mm was polished and the deflection of the cylindrical tube was reduced to 10 mm.
μm or less and surface roughness of 4 μm or less in Rz notation are subjected to masking on the upper and lower ends, and a blast machine using amorphous alumina abrasive grains (# 300) is used to form a 3.92 ×
The blast treatment was performed at a blast pressure of 10 ^-2 MPa (4.0 kgf / cm). The masking width at both ends of the sleeve is 3
mm. The surface roughness Ra of this blasting sleeve was 1.12 μm on average at six points. A magnet was inserted into this sleeve, and flanges were attached to both ends to form a developing sleeve 4.

Example 1 Resin A 100 parts by mass Magnetite 90 parts by mass (octahedral, average particle size 0.22 μm, BET = 7.9 m ² / g, silicon content 0.35 wt%, σs = 84) 0.5 Am ² / kg, σr = 10.9 Am ² / kg) ・ 4 parts by mass of low molecular weight polypropylene wax (melting point: 130 ° C.) ・ 2 parts by mass of imidazole derivative compound example (4)

After the above materials were well mixed by a Henschel mixer, they were melt-kneaded by a twin-screw kneading extruder set at 140 ° C. The obtained kneaded material was cooled, coarsely pulverized by a cutter mill, and then finely pulverized using a fine pulverizer using a jet stream, and the obtained finely pulverized material was further classified by an air classifier to obtain a weight average particle size. A classified fine powder having a diameter of 8.5 μm was obtained.

100 parts by mass of the obtained classified fine powder was mixed with a silica fine powder (BET specific surface area 200 m
² / g) Amino-modified silicone oil per 100 parts by mass (amine equivalent: 830, viscosity at 25 ° C: 70 cSt)
0.8 parts by mass of the hydrophobic silica treated with 17 parts by mass was added, mixed with a Henschel mixer, and sieved with a mesh having an opening of 150 μm to obtain a positively chargeable one-component magnetic toner 1.

With respect to the obtained toner 1, the following evaluation tests were performed.

Offset resistance evaluation test: Commercial copying machine N
Using P6030 (manufactured by Canon Inc.), the developing sleeve was converted to the developing sleeve 1 shown in the developing sleeve manufacturing example 1 of the present invention, the fixing device was removed outside, and the fixing roller was operated outside the copying machine, and the fixing roller was operated. The temperature can be set arbitrarily,
Offset resistance was evaluated by passing an unfixed image using an external fixing device modified so that the process speed was 100 mm / sec. At the time of evaluation, the temperature of the fixing roller was set to 230 ° C., the state of the offset was observed, and the images were classified into the following ranks (evaluation environment:
Normal humidity (23 ° C./60% RH).

Offset rank A No offset is seen at all. B Very slight offset is observed. C offset occurs.

Evaluation Test of Sleeve Coatability: Using a commercially available copying machine NP6030 (manufactured by Canon Inc.), the developing sleeve was replaced with the developing sleeve 1 shown in the developing sleeve manufacturing example 1 of the present invention, and the toner on the sleeve was changed. Look at the coat,
Blotch generation levels were classified into the following ranks (evaluation environment: normal temperature / normal humidity (23 ° C./60% RH), normal temperature / low humidity (23 ° C./5% RH), high temperature / high humidity (32.5 ° C.) / 8
0% RH)).

Blotch rank A No occurrence. B Slightly generated at the end of the sleeve. C Very slight, but does not affect the image. D: It occurs clearly and affects the image.

Image evaluation test: Commercial copying machine NP6030
(Canon Co., Ltd.), the developing sleeve was replaced with the developing sleeve 1 shown in the developing sleeve manufacturing example 1 of the present invention, 10,000 copies were made under normal temperature / normal humidity environment, and normal temperature / low humidity environment was used. In each environment of high temperature / high humidity, 5,000 copies were made, and the image density and fog were evaluated (evaluation environment: normal temperature / normal humidity (23 ° C./60% R)
H), room temperature / low humidity (23 ° C./5% RH), high temperature / high humidity (32.5 ° C./80% RH)).

Also, after copying 10,000 sheets in a normal temperature / normal humidity environment, a part of the surface of the developing sleeve was wiped off with washing with ethanol, a solid black image was printed, and the image density before and after the wipe with ethanol was measured. The sleeve contamination was evaluated by calculating the difference, and classified into the ranks shown below.

Sleeve contamination rank A less than 0.03 B 0.03 or more and less than 0.10 C 0.10 or more but less than 0.20 D 0.20 or more The image density was measured using a Macbeth reflection densitometer (manufactured by Macbeth).
It measured using. The fog is measured using a "reflection densitometer" (manufactured by Tokyo Denshoku Technology Center Co.),
Measure the reflection density of the transfer paper after copying the solid white,
The difference is defined as a fog value, and the smaller the numerical value, the better the fog suppression.

The results of the offset resistance test, sleeve coat property test and image evaluation test are shown in Table 1.

Example 2 A classified fine powder and toner 2 were obtained in the same manner as in Example 1 except that the resin A was changed to the resin B. This toner 2 was evaluated in the same manner as in Example 1. Table 1 shows the evaluation results.

Example 3 A classified fine powder and a toner 3 were obtained in the same manner as in Example 1 except that the resin A was changed to the resin C. This toner 3 was evaluated in the same manner as in Example 1. Table 1 shows the evaluation results.

Example 4 A classified fine powder and toner 4 were obtained in the same manner as in Example 1 except that the resin A was changed to the resin D. This toner 4 was evaluated in the same manner as in Example 1. Table 1 shows the evaluation results.

Example 5 A classified fine powder and toner 5 were obtained in the same manner as in Example 1 except that the resin A was changed to the resin E. This toner 5 was evaluated in the same manner as in Example 1. Table 1 shows the evaluation results.

Comparative Example 1 A classified fine powder and a toner 6 were obtained in the same manner as in Example 1 except that the resin A was changed to the resin F. This toner 6 was evaluated in the same manner as in Example 1. Table 1 shows the evaluation results.

Comparative Example 2 Classified fine powder and toner 7 were obtained in the same manner as in Example 1 except that resin A was changed to resin G. This toner 7 was evaluated in the same manner as in Example 1. Table 1 shows the evaluation results.

Example 6 A classified fine powder and toner 8 were obtained in the same manner as in Example 1 except that the compound example (4) of the imidazole derivative was changed to the compound example (5). This toner 8 was evaluated in the same manner as in Example 1. Table 1 shows the evaluation results.

Example 7 A classified fine powder and toner 9 were obtained in the same manner as in Example 1 except that the compound example (4) of the imidazole derivative was changed to the compound example (7). This toner 9 was evaluated in the same manner as in Example 1. Table 1 shows the evaluation results.

Example 8 A classified fine powder and toner 10 were obtained in the same manner as in Example 1 except that the compound example (4) of the imidazole derivative was changed to the compound example (11). This toner 10 was evaluated in the same manner as in Example 1. Table 1 shows the evaluation results.

Example 9 A classified fine powder and toner 11 were obtained in the same manner as in Example 1 except that the compound example (4) of the imidazole derivative was changed to the compound example (12). This toner 11 was evaluated in the same manner as in Example 1. Table 1 shows the evaluation results.

Comparative Example 3 A classified fine powder and toner 12 were obtained in the same manner as in Example 1 except that the compound example (4) of the imidazole derivative was changed to a nigrosine dye. This toner 12 was evaluated in the same manner as in Example 1. Table 1 shows the evaluation results.

Example 10 Using the toner 1 obtained in Example 1, each evaluation other than the offset resistance test was performed in the same manner as in Example 1 except that the developing sleeve 1 was changed to the developing sleeve 2. Was. Table 1 shows the evaluation results.

[Comparative Example 4] Toner 1 obtained in Example 1
Each evaluation other than the offset resistance test was performed in the same manner as in Example 1 except that the developing sleeve 1 was changed to the developing sleeve 4. Table 1 shows the evaluation results.

[Example 11] 100 parts by mass of resin A 3.5 parts by mass of copper phthalocyanine 3 parts by mass of low molecular weight polypropylene wax (melting point 130 ° C) 3 parts by mass of compound of imidazole derivative (4) 2 parts by mass

[0213] The above materials were premixed well with a Henschel mixer, and then melt kneaded with a twin screw extruder set at 120 ° C. The obtained kneaded material was cooled, coarsely pulverized by a cutter mill, and then finely pulverized using a fine pulverizer using a jet stream, and the obtained finely pulverized material was further classified by an air classifier to obtain a weight average particle size. A classified fine powder having a diameter of 8.5 μm was obtained.

To 100 parts by mass of the obtained classified fine powder, a fine silica powder (BET specific surface area: 200 m
² / g) Amino-modified silicone oil per 100 parts by mass (amine equivalent: 830, viscosity at 25 ° C: 70 cSt)
1.0 part by mass of hydrophobic silica treated with 17 parts by mass was added, mixed with a Henschel mixer, and sieved with a mesh having an opening of 150 μm to obtain a positively chargeable non-magnetic one-component toner 13.

Using a commercially available copying machine FC-330 (manufactured by Canon Inc.), the developing sleeve was converted to the developing sleeve 3 of the present invention, and 1000 sheets were copied under a normal temperature / humidity environment. And 1000 copies were made in each environment of high temperature / high humidity environment, and the image density and fog were evaluated in the same manner as in Example 1 (evaluation environment: normal temperature / normal humidity (23 ° C./60% RH), normal temperature / Low humidity (23 ℃ / 5%
RH), high temperature / high humidity (32.5 ° C./80% RH)).

After 1000 copies were made in a normal temperature / normal humidity environment, a part of the surface of the developing sleeve was wiped cleanly with ethanol, and sleeve contamination was evaluated in the same manner as in Example 1. Table 1 shows the evaluation results.

[0219]

[Table 1]

[0218]

According to the image forming method of the present invention, the specific imidazole derivative shown in the present invention is used as a charge control agent in a positive toner into which an acid group has been introduced, thereby impairing the charging characteristics and developing characteristics of the toner. Offset resistance can be dramatically improved without
By using a toner carrier having a resin layer formed on a metal substrate, the charging ability is greatly improved and the development characteristics can be improved, and a high-definition image free from image density reduction and fog over a long period of time can be obtained. Can be provided stably.

[Brief description of the drawings]

FIG. 1 is a schematic view of a cross section of a part of a toner carrier of the present invention.

FIG. 2 is a cross-sectional view of a part of the toner carrier of the present invention ((A)
(B) is a schematic diagram before polishing, and (B) is after polishing.

FIG. 3 is a schematic view showing an example of a magnetic developer supply system developing device in which the toner carrier of the present invention is incorporated (using a magnetic blade as a regulating member).

FIG. 4 is a schematic view showing another example of a magnetic developer supply system developing device in which the toner carrier of the present invention is incorporated (an elastic blade is used as a regulating member).

FIG. 5 is a schematic diagram for explaining the image forming method of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 coating layer (resin layer) 2 conductive substance 3 filler 4 binder resin for resin layer 5 solid lubricant 6 cylindrical substrate 7 photosensitive drum (latent image holding body) 8 regulating blade 9 hopper 10 magnetic toner 11 magnet 12 cylinder Substrate 13 coating layer (resin layer) 14 developing sleeve (toner carrier) 15 power supply 17 elastic blade A rotating direction of developing sleeve B rotating direction of photosensitive drum D developing unit 501 coating layer (resin layer) 502 solid lubricant 503 conductive Active substance 504 Filler 505 Binder resin for resin layer 506 Cylindrical substrate 801 Latent image carrier 801a Photoconductive layer 801b Conductive base layer 802 Charging roller 802a Conductive elastic layer 802b Core 803 Charging bias power supply 804 Image exposure 805 Developing roller 806 Transfer roller 806a Conductive elastic layer 806b Core 807 Transfer bar Ass supply 808 transfer material 809 cleaning device 810 extinguishing light 811 heating and pressing means 813 a development bias power supply

Continued on the front page (72) Inventor Hirohide Tanigawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc.

Claims (2)

[Claims] 1. A positively-charged toner containing at least a binder resin for a toner, a colorant and a charge control agent is transported by a toner carrier having a resin layer on a metal substrate, and is transferred onto an electrostatic latent image carrier. In the image forming method in which the formed electrostatic latent image is developed by transferring the positively chargeable toner from the toner carrier to form a toner image, the toner binder resin has an acid value of the entire polymer component. 0.5
mgKOH / g to 50 mgKOH / g, wherein the charge control agent comprises an imidazole derivative represented by the following general formula (1). Embedded image (R ₁ and R ₂ in the general formula (1) are a hydrogen atom, an alkyl group having 1 to 35 carbon atoms (which may be branched),
Represents an aryl group or an aralkyl group, which may be the same or different, may have a substituent, and R ₃ is an alkyl group having 1 to 35 carbon atoms (which may be branched) , An aryl group or an aralkyl group. ) 2. The binder resin for a toner according to claim 1, wherein the acid value of the whole polymer component is 0.5 mgKOH / g to 30 mgKOH / g.
2. The image forming method according to claim 1, wherein g is g.