JP2000155462A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the prescription of such toner that a sleeve is not soiled even when the small-diameter toner is used and excellent image quality without a blotch and pitch irregularity and high density can be maintained extending over a long term under every environment and to obtain a developing device using this toner and the above plated sleeve. SOLUTION: This developing device 13 is provided with the cylindrical sleeve 5 arranged by being opposed to a latent image carrier 42 for carrying a latent image and constituted so that developer carried on the sleeve 5 is fed to a part opposed to the carrier 12 and the latent image is developed by the developer at the opposed part. The sleeve 5 is provided with a sleeve base material 51 and a plating layer 52 formed at the surface of the material 51 by electroless plating. Besides, the developer is provided with the toner including at least the copolymer of styrene and butadiene being as binding resin and a triphenylmethane compound being as charge control agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device for an electrophotographic image forming apparatus, and more particularly, to a developing device using a plated sleeve as a developing sleeve of a one-component developing device, and a developing device using the same. It relates to a developer.

[0002]

2. Description of the Related Art Conventionally, the surface of a developing sleeve has been made uneven in order to transport a developer. As old as JP-A-54-
No. 79043, a knurled grooved sleeve in a two-component developing device or a blasting process mainly for a one-component developing device as disclosed in Japanese Patent Application Laid-Open No. 55-26526. There is a sleeve.

[0003] In particular, as a material of the blasted sleeve, a material having a relatively high hardness, for example, SUS (Vickers hardness Hv ≒ 200) or the like is often used in order to prevent the unevenness of the sleeve from being worn down during long-term use. I was S
Japanese Patent Application Laid-Open No. 57-66 discloses a blast treatment for US.
As shown in Japanese Patent No. 455, Alundum blast using alumina particles has been used for a long time. Later, JP-A-57-116372, JP-A-58-1197
As disclosed in Japanese Unexamined Patent Application Publication No. 4 and JP-A-1-131586, since the surface of the alundum is formed with sharp irregularities, particularly during long-term use, toner is agitated in a developing device. In the case where destruction and diameter reduction occur and development is repeated for a long period of time, fine-grained toner is generated in the developing device, and fine toner etc. is embedded in the depression, and the developer is charged in that part. In addition, a method of blasting using spherical particles (for example, glass beads or the like) has been proposed to prevent image defects and cause image defects (hereinafter, referred to as “sleeve contamination”).

FIG. 6 is a schematic view of a roughness cross-sectional curve of an alundum blast, and FIG. 7 is a schematic view of blasting with glass beads. As shown in FIG. 7 (compared to FIG. 6), these are intended to reduce sleeve contamination by making the cross-sectional curve smoother.

On the other hand, in recent years, since SUS is expensive as a sleeve material, an aluminum alloy has been used for the purpose of cost reduction.

Alternatively, when an amorphous silicon drum (hereinafter referred to as "a-Si drum"), which has a long life, is used as a photosensitive drum, it is becoming essential to use an aluminum sleeve. The reason is as follows.
When the a-Si drum is used under high humidity, "image deletion" is more likely to occur as compared with the OPC drum. "Image flow"
This means that the charged products (NOx and the like) attached to the drum surface absorb moisture, the electrical resistance of the drum surface decreases, and
This is a phenomenon in which surface charges on a drum forming an electrostatic latent image due to exposure flow around. Naturally, as a result, an image defect such as blurring of the developed image occurs. In order to prevent this, a sheet-like heating element is inserted to prevent moisture absorption of NOx. (Of course, the surface can be cut easily like an OPC drum, and if the surface layer of both NOx is cut, it is effective for image flow. However, the life of the a-Si drum is naturally shortened.) At this time, the developing sleeve facing the a-Si drum is thermally deformed during standby and warps. This is the first copy after standby, for example, when a halftone image having a uniform density is copied, it appears as sleeve pitch-like density unevenness. Moreover,
This thermal deformation is remarkable in a SUS sleeve having poor heat conductivity, and as a countermeasure, an aluminum sleeve having good heat conductivity has come to be used. In the case of an aluminum sleeve, this thermal deformation is slight, so that it is hardly noticeable.

For the above reasons, aluminum sleeves have become the mainstream material for developing sleeves instead of SUS.

However, as is well known, the hardness of the aluminum sleeve is low (Hv ≒ 100), so that the rough sleeve surface after blasting is easily and quickly worn as it is.

For this reason, as shown in Japanese Patent Application Laid-Open No. 1-276174, aluminum coated with high hardness resin is sometimes used. This is one in which carbon graphite is dispersed in a phenol resin to increase the hardness while maintaining the conductivity required for the sleeve (hereinafter, referred to as “carbon coated sleeve”). Since the resin is applied by dipping or spraying by about 10 to 20 μm, it slightly inherits the unevenness of the underlying aluminum, but its fine surface properties are basically flat as shown in the schematic diagram of FIG. Phenolic resin 100 in carbon graphite 10
2 is embedded, and the cross-sectional shape of the roughness is relatively close to the above-described alundum blast.

[0010] Therefore, the developer is embedded in the sharp unevenness, and there is a possibility that sleeve contamination is more likely to occur than in the SUS sleeve. However, since the carbon-coated sleeve is gradually removed, contaminants are also removed together and the sleeve may not be contaminated, but the life is shortened due to the removal.

Conventionally, carbon coated sleeves have been used for negatively charged OPC LBPs, low-speed digital copying machines, and the like. One of the reasons is that in the case of the LBP, since the developing sleeve is also included in the cartridge as a consumable item, it is not intended for long-term use. In addition, negatively charged OPC
, The polarity of the toner is negative with the same polarity as the drum, but the resin used for the toner (for example, styrene-acryl, polyester, etc.) basically has a strong negative charge, so it is finished as a toner. One of the reasons is that the chargeability as a negative toner is high after that, and in such a case, even if sleeve contamination occurs, a sufficient amount of toner charge for image formation can be obtained.

However, in recent years, the required level for a copied image has been improved, so that higher density and higher image quality (sharpness, etc.) than ever have been demanded. And there is a tendency to further reduce the particle size of the toner for higher image quality,
This is a direction in which sleeve contamination is more likely to occur, regardless of the life of the sleeve or the polarity of the toner. When sleeve contamination occurs, the image density is reduced, and the user's requirements cannot be satisfied. This will be described with reference to FIG.

FIG. 9 is a cross-sectional view of the roughness obtained by enlarging one peak of the SUS described with reference to FIG. 7 in which spherical particle blasting is performed. Although the toner does not enter into the small irregularities inside, even if the SUS particles are blasted by reducing the diameter, they enter the small dents (a, b, c in the figure) in the large swell. It is considered that since the amount of toner to be generated increases stochastically, the toner is more easily contaminated than before.

That is, as the toner becomes finer, further measures against sleeve contamination have become necessary to further extend the life of the developing device.

For this purpose, for example, Japanese Patent Application Laid-Open No. 9-32376
As disclosed in Japanese Patent Laid-Open No. 6-206, there has been proposed a developing sleeve in which an aluminum sleeve is subjected to an FGB blast treatment and then subjected to electroless plating to remove even minute irregularities on the surface of the sleeve. This will be described with reference to FIG.

FIG. 10 is a schematic diagram of a roughness profile curve of a sleeve similar to FIGS. In the figure, the one-dot broken line shows the roughness curve when the aluminum sleeve is subjected to the FGB blasting, and the solid line shows the roughness curve when electroless plating is performed thereon. Originally, FGB for relatively low hardness aluminum
As a result of the blasting process, irregularities in the blasting process (SUS
More clean than those that have been subjected to FGB blasting)
Finished almost uniformly. That is, as shown in FIG. 7, SUS blasted with FGB has poor uniformity and many cracks such as minute defects in one recess. On the other hand, FIG. 9 shows unevenness and uniform cracks. It turns out that there are few.

The difference is that crater-like marks formed by the collision of spherical particles are relatively clean because aluminum is soft, whereas SUS has crater-like marks but is hard because it is hard. It is considered that it is difficult to crack and cracks are easily formed.

By using a "plating sleeve" in which an aluminum sleeve is plated as described above, sleeve contamination due to a reduction in toner particle diameter can be prevented more than a SUS sleeve or a carbon coated sleeve. A developing sleeve having no thermal deformation due to a drum heater such as a sleeve and having a longer life than a carbon coated sleeve can be obtained.

[0019]

However, when the above-mentioned electroless Ni-P plating sleeve was examined, no problem occurred in a normal environment. Problem has occurred.

The inventors of the present invention have examined the cause of the problem. As a result, electroless plating sleeves made of Ni-P, Ni-B, Cr, Pd-P, etc. have (a) slightly less chargeability than SUS. It was found that the change in the charging ability with respect to the toner particle size was large. Hereinafter, the phenomenon as the problem will be described in detail.

Table 1 shows the toner tribo (triboelectric charge) after endurance in each environment when endurance of 100,000 copies of A4 size paper is performed using the above-mentioned Ni-P plating sleeve. The results for the SUS sleeve are also shown for comparison. The toner used here is a conventionally well-known styrene-acrylic toner, and Nigrosine is used as a charge control agent, and the weight average particle diameter of the toner is 6 μm, which is smaller than the conventional toner. The details will be described later together with the description of the developing device and the image forming apparatus.

[0022]

[Table 1]

As shown in Table 1, with respect to the "tribo after durability", the Ni-P plating sleeve has a higher tribo after durability than SUS under the normal temperature and low humidity environment, but is reversed on the high humidity environment side. You can see that. Therefore, it is considered that a low concentration occurred in a high humidity environment.

"Normal temperature and low humidity" refers to an environment of 23 ° C. and 5% relative humidity, “normal temperature and normal humidity” refers to an environment of 23 ° C. and 60%, and “high temperature and high humidity” refers to an environment of 30 ° C. and 80%. The same applies during the description.

In order to investigate the above-mentioned cause, the developing sleeve after endurance was wiped with a solvent to remove contaminants adhering to the sleeve, and the tribo was measured again (with the same endurance developer). "Tribo after decontamination".

When the sleeve contamination is excluded from the above, S
It can be seen that the tribo is lower in the Ni-P plating sleeve than in the US. However, the toner is not contaminated on the Ni-P plating sleeve, as can be seen from the fact that the tribo does not change before and after wiping the sleeve. For this reason, the Ni-P plating sleeve, which originally has a little but inferior charging ability than SUS, has N / L to N / N
As a result, the overall endurance tribo is SU
It is considered that it is higher than S. Therefore, in a low humidity environment to a normal humidity environment (N / L to N / N), the SUS sleeve causes a large decrease in concentration due to contamination.
With a Ni-P plating sleeve, the concentration can be kept high.

Next, the reason why the tribo of the Ni-P plated sleeve after durability was lower in a higher humidity environment was examined. In a high humidity environment, the value of tribo is low because the toner absorbs moisture and its resistance is reduced, but the difference is hardly shown in the numerical value when the initial agent before durability is used. Actually, the initial tribo in each of the above environments is about 10% for Ni-P regardless of the environment.
１１11 mC / kg, and SUS is about 12 to 13 mC / kg, which is not as large as the tribo after durability shown in Table 1.

Generally, the toner tribo is higher as the toner particle size is smaller, and the toner used for image formation is more likely to be consumed because of the higher tribo. Therefore, it is known that a toner having a high toner tribo, that is, a toner having a small toner particle diameter, is gradually consumed in a high-humidity environment, resulting in a large difference between the toner particle diameter after the durability and the toner tribo. .

It is also known that the toner is broken or reduced in diameter due to agitation in the developing device, and when development is repeated for a long period of time, particulate toner is generated in the developing device. This also affects the toner particle size after toner running and the toner tribo.

Then, the toner particle size of the developer subjected to durability in each environment was measured.
On the other hand, both the Ni-P and SUS sleeves show the "toner particle size after endurance" in Table 1, and there was no difference between the sleeves regarding the particle size after endurance. Therefore, the change in the toner particle diameter from the initial stage is the same in both sleeves in a low humidity environment, about 1 μm in normal humidity, and about 2 μm in high humidity.

Despite the difference in toner particle diameter between the two sleeves after the endurance, the tribo and the SU in the Ni-P plating sleeve at low humidity are low when viewed by the tribo after the endurance excluding the contamination.
While the tribo difference in S is 2 mC / kg, the difference between the two at high humidity is as large as 4 mC / kg. From this, it is considered that the change rate of the toner tribo with respect to the change of the toner particle diameter is larger in the Ni-P plating sleeve than in the SUS sleeve. That is, N
That is, the i-P plating sleeve has a larger change in the ability to apply charge from the sleeve to the toner particle diameter than the SUS sleeve.

FIG. 11 is a graph of Table 1, wherein the solid line in FIG. 11 shows the change in tribo with respect to the toner particle size of the Ni-P plating sleeve, and the broken line in FIG. Show it. In the case of the SUS sleeve, contamination occurs after the endurance, and the tribo is reduced accordingly. Where Ni
Since the -P plating sleeve does not cause contamination even after the durability, the tribo after the durability remains as a solid line.

As described above, the change in tribo to the toner particle size is larger in the Ni-P plating sleeve than in SUS, and therefore, even though it is less likely to be contaminated as compared with SUS, under a high humidity environment (N / N to H / H). It is considered that the tribo is lower than SUS after the endurance in (2) and the concentration is lower than SUS.

As described above, it has been found that the Ni-P plating sleeve has (a) a slightly poor chargeability and (b) a large change in the charging ability with respect to the toner particle size.

Therefore, in order to prevent sleeve contamination, which is likely to occur when the toner particle size is made smaller than before,
Although the Ni-P electroless plating sleeve is effective, there is a problem that the concentration is low particularly in a high humidity environment.

Even when the Ni-P plating sleeve is used, it is of course advantageous to reduce the concentration under a high humidity environment if the toner particle diameter is made smaller and the initial tribo before durability is increased. The toner having a weight average particle diameter of about 4 μm has a problem that it is difficult to obtain a solid black density in the first place, and it is difficult to clean the photosensitive member.

On the other hand, in the case of the SUS sleeve, if the initial tribo is increased so as to compensate for the decrease in tribo due to contamination, the same concentration as that of the Ni-P plating sleeve can be obtained from normal humidity to low humidity even after durability. It is necessary to raise the initial tribo to about 15 to 20 mC / kg for that purpose. In this case, however, the tribo is further increased by using a SUS sleeve having a high tribo, but it is particularly low in humidity. At the initial stage under the environment, electrical toner aggregation (hereinafter referred to as “blotch”) due to local excessive charging occurs, resulting in sleeve coat failure.

Further, it is a matter of course that the SUS sleeve cannot solve the sleeve pitch unevenness related to the thermal conductivity.

Therefore, an object of the present invention is to provide an electroless plating plating sleeve which is made of Ni-P, Ni-B or C-
Even in the case of using a sleeve such as r, Pd-P sleeve which is slightly inferior in chargeability to SUS and has a large change in tribo to the toner particle size, these problems can be solved by improving the toner. As a result, even if a toner having a small particle diameter is used, the toner does not contaminate the sleeve, does not generate blotches, has good image quality without pitch unevenness, and maintains a high density over a long period of time. An object of the present invention is to provide a developing device using such a toner and the plating sleeve.

[0040]

The above problem is partly due to the fact that the chargeability of the electroless plating sleeve is lower than that of SUS, but the reason is not clear. It is thought that impurities such as P, B, etc. in the electroless plating are affected because they contain substances other than metals, but in any case, the charging series is lower than SUS, Conceivable.

The large change of the toner tribo with respect to the toner particle diameter is another factor of the above-mentioned problem, but the reason is not fully understood. It may be related to the fact that the surface property of the plated sleeve is slightly different from the surface after blasting, which has been conventionally known. However, the average roughness parameters such as Ra and Sm are considered. It is the present situation that cannot be grasped.

The "poor chargeability" and "difference in surface properties" which are the causes of the above-mentioned problems relating to the plating sleeve are inherent to the plating sleeve and are inevitable. Conceivable.

Therefore, in the present invention, a toner prescription suitable for a developing sleeve coated with electroless plating, which is slightly lower in chargeability than SUS, and has a large change in tribo with respect to the toner particle size, and development using the toner By providing the device, the above problem can be solved.

That is, the present invention has a cylindrical sleeve which is arranged to face a latent image carrier for carrying a latent image, and the developer carried on the sleeve is provided with the latent image carrier. And a developing device for developing the latent image with the developer at the facing portion, wherein the sleeve comprises: (i) a sleeve base; and (ii) electroless plating on the surface of the sleeve base. Wherein the developer has a toner containing at least a styrene-butadiene copolymer as a binder resin and a triphenylmethane compound as a charge control agent. And a developing device.

[0045]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The toner of the present invention contains a styrene-butadiene copolymer in a binder resin. Styrene-
Since the butadiene copolymer is a kind of thermoplastic elastomer, by adding it to the toner, impact resistance can be imparted to the toner. This allows
The destruction and small diameter of the toner due to agitation in the developing device are prevented, and the generation of particulate toner in the developing device is suppressed even when development is repeated for a long time.
Therefore, even in combination with a Ni-P plating sleeve having a large change rate of the toner charging ability with respect to a change in toner particle size, a difference in toner tribo before and after endurance can be suppressed, and generation of fine toner particles can be suppressed. As a result, the occurrence of sleeve contamination can be effectively suppressed.

On the other hand, the styrene-butadiene copolymer is
It has higher electric resistance than styrene-acrylic resin and polyester resin, and therefore has a property that it is difficult to alleviate charging. Therefore, even when there is an environmental change, the holding performance of the tribo is high and the characteristics excellent in the developing property are exhibited.

In particular, when a styrene-butadiene copolymer is prepared by emulsion polymerization, the emulsifier remains to exhibit positive (positive chargeability) due to the remaining emulsifier, and is particularly effective when applied to a positive toner. it can. Therefore, Ni-P, which is slightly inferior in charging performance to SUS,
Even in combination with a plating sleeve, sufficient image quality can be maintained over the entire environment, and good image quality that does not cause blotches in low humidity environments such as SUS and sleeve pitch unevenness after standing by standing,
High image density can be maintained over a long period of time.

The styrene-butadiene copolymer used in the present invention is obtained by copolymerizing a styrene monomer and butadiene. Here, as the styrene monomer, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-dodecylstyrene, p-methoxystyrene, p
-Phenylstyrene, p-chlorostyrene and the like.

The styrene-butadiene copolymer used in the present invention has a molecular weight distribution of G
n is preferably 1 × 10 ³ to 1 × 10 ⁵ , and more preferably 2 × 1
0 ^{3 to} 5 × 10 ⁴ are preferred. Further, Mw is 5 × 10 ³ or more.
1 × 10 ⁶ is preferable, and 1 × 10 ^{4 to} 5 is more preferable.
× 10 ⁵ , more preferably 2 × 10 ³ to 2 × 1
0 ⁵ region, preferably it is preferred that there are at least one peak in the region of ^{3 × 10 3 ~1.5 × 10 5} . Further, Mw / Mn is preferably 2.0 or more, more preferably 3.0 or more.

In the present invention, the content of the styrene-butadiene copolymer contained in the binder resin is preferably 1 to 40% by weight in the binder resin. More preferably, the content is 5 to 35% by weight. When the content of the copolymer is 1
If the content is less than 10% by weight, it is difficult to obtain the effect.
If the amount exceeds 0% by weight, the rubber elasticity of the binder resin becomes large, and good fixing property cannot be obtained.

The styrene-butadiene copolymer preferably has a styrene content of 50 to 95% by weight. More preferably, the content is 60 to 93% by weight. The preferred butadiene content is 5 to 50% by weight, more preferably 7 to 40% by weight. In the present invention, when a styrene-butadiene copolymer having a styrene content of less than 50% by weight is used, the glass transition point of the binder resin is low, and the obtained toner has high cohesiveness. .
On the other hand, when a copolymer having a styrene content of more than 95% by weight is used, the softening point of the constituent binder resin becomes high, and good fixing properties cannot be obtained. .

Further, terpolymers containing other comonomers may be used. Examples of the comonomers include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, and acrylic acid. Monocarboxylic acid having a double bond such as 2-ethylhexyl, phenyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, or a substituted product thereof Dicarboxylic acids having a double bond such as maleic acid, butyl maleate, methyl maleate, and dimethyl maleate and substituted products thereof; vinyl esters such as vinyl chloride, vinyl acetate and vinyl benzoate; D Ren, propylene, ethylenic olefins such as butylenes; such as vinyl methyl ketone, vinyl ketones such as vinyl hexyl ketone;
For example, vinyl methyl ether, vinyl ethyl ether,
Vinyl ethers such as vinyl isobutyl ether;
And vinyl monomers such as The content of the other monomer is preferably 15% by weight or less. More preferably, the content is 10% by weight or less.

The styrene-butadiene copolymer used in the present invention preferably has a gel content of 60% by weight or less, more preferably 50% by weight or less. Further, the styrene-butadiene copolymer may be partially cross-linked,
As the crosslinking agent, for example, a bifunctional monomer such as divinylbenzene or a radical initiator such as benzoyl peroxide can be used.

In the present invention, the resin used for the binder resin other than the styrene-butadiene copolymer includes:
The following resins are mentioned.

For example, homopolymers of styrene and its substituted substances such as polystyrene, poly-p-chlorostyrene and polyvinyl toluene; styrene-p-chlorostyrene copolymer, styrene-vinyltoluene copolymer, styrene-
Vinyl naphthalene copolymer, styrene-acrylate copolymer, styrene-methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-
Styrene copolymers such as vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer; 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 resin, polyamide resin, furan resin, epoxy resin, xylene resin, polyvinyl butyral, terpene resin, cumarone indene resin, and petroleum resin can be used. Preferred binder resins include styrene copolymers and polyester resins.

Examples of the comonomer for the styrene monomer of the styrene copolymer include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, and acrylic acid.
Monocarboxylic acid having a double bond such as 2-ethylhexyl, phenyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide or a substituted product thereof; For example, dicarboxylic acids having a double bond such as maleic acid, butyl maleate, methyl maleate, and dimethyl maleate and substituted products thereof; vinyl esters such as vinyl chloride, vinyl acetate, and vinyl benzoate; Olefins such as vinyl, propylene and butylene; vinyl ketones such as vinyl methyl ketone and vinyl hexyl ketone; vinyl alcohols such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether Ethers; such vinyl monomers are used alone or two or more.

The styrene-based polymer or styrene-based copolymer may be cross-linked or a mixed resin.

As a crosslinking agent for the binder resin, a compound having two or more polymerizable double bonds can be mainly used. For example, aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; carboxylic esters having two double bonds such as ethylene glycol diacrylate, ethylene glycol dimethacrylate and 1,3-butanediol dimethacrylate; divinylaniline , Divinyl ether, divinyl sulfide, divinyl sulfone, and divinyl compounds; and compounds having three or more vinyl groups are used alone or as a mixture.

The method for synthesizing the binder resin may be any of a bulk polymerization method, a solution polymerization method, a suspension polymerization method and an emulsion polymerization method.

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 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 composition.

As the solvent used in the solution polymerization, xylene, toluene, cumene, cellosolve acetate, isopropyl alcohol, benzene and the like are used. In the case of a styrene monomer mixture, xylene, toluene or cumene is preferred. Each is appropriately selected depending on the polymer to be polymerized.

The reaction temperature varies depending on the solvent used, the initiator and the polymer to be polymerized.
It is good to carry out at ° C. In the solution polymerization, it is preferable to perform the polymerization at 30 to 400 parts by weight of the monomer with respect to 100 parts by weight of the solvent.

Further, it is also preferable to mix another polymer in the solution at the end of the polymerization, and several kinds of polymers can be mixed.

As a polymerization method for obtaining a high molecular weight component or a gel component, an emulsion polymerization method or a suspension polymerization method is preferable.

Among them, the emulsion polymerization method is a method in which a monomer (monomer) almost insoluble in water is dispersed as small particles in an aqueous phase 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. Furthermore, due to the relatively simple polymerization process and the fact that the polymerization product is fine particles, in the production of toner,
This method is advantageous as a method for producing a binder resin for a toner as compared with other methods 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 remove the polymer. Therefore, suspension polymerization is a simple method.

In the suspension polymerization, 100 parts by weight or less of the monomer (preferably 10 parts by weight) is added to 100 parts by weight of the aqueous solvent.
To 90 parts by weight). Usable dispersants include polyvinyl alcohol, partially saponified polyvinyl alcohol, calcium phosphate, and the like. There is an appropriate amount in terms of the amount of monomer relative to the aqueous solvent, and generally 0.05 to 100 parts by weight of the aqueous solvent. Used in an amount of 1 part by weight. The polymerization temperature is suitably from 50 to 95 ° C., but should be appropriately selected depending on the initiator used and the intended polymer. As the type of the initiator, any initiator that is insoluble or hardly soluble in water can be used.

Examples of the initiator used include t-butylperoxy-2-ethylhexanoate, cumin perpivalate, t-butylperoxylaurate, benzoyl peroxide, lauroyl peroxide, octanoyl peroxide, -T-butyl peroxide, t
-Butylcumyl peroxide, dicumyl peroxide, 2,2′-azobisisobutyronitrile, 2,2 ′
-Azobis (2-methylbutyronitrile), 2,2'-
Azobis (2,4-dimethylvaleronitrile), 2,
2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), 1,1-bis (t-butylperoxy)
3,3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, 1,4-bis (t-butylperoxycarbonyl) cyclohexane, 2,2-bis (t-butylperoxy) Octane,
n-butyl-4,4-bis (t-butylperoxy) valerate, 2,2-bis (t-butylperoxy) butane, 1,3-bis (t-butylperoxy-isopropyl) benzene, 2, 5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5
-Di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane,
Di-t-butylperoxyisophthalate, 2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane, di-t-butylperoxy-α-methylsuccinate, di-t-butyl Peroxydimethylglutarate, di-t-butylperoxyhexahydroterephthalate, di-t-butylperoxyazelate,
2,5-dimethyl-2,5-di (t-butylperoxy) hexane, diethylene glycol-bis (t-butylperoxycarbonate), di-t-butylperoxytrimethyl adipate, tris (t-butylperoxy) ) Triazine, vinyltris (t-butylperoxy) silane and the like, which can be used alone or in combination.

The amount used is 0.05 parts by weight or more (preferably 0.1 to 15 parts by weight) with respect to 100 parts by weight of the monomer.

In the present invention, the composition of the polyester resin that can be used together with the styrene-butadiene copolymer is as follows.

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

[0072]

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. ) A diol represented by the following formula (B);

[0073]

Embedded image 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.

Further, 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 includes, for example, trimellitic acid, pyromellitic acid,
2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid,
2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, tetra (methylenecarboxyl) methane, 1,2,7,8- Oxanetetracarboxylic acid, empol trimer acid, and anhydrides and lower alkyl esters thereof;

[0078]

Embedded image (Wherein X is an alkylene group or alkenylene group having 5 to 30 carbon atoms having at least one side chain having 3 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 of the polyester resin used in the binder resin of the present invention is 40 to 60 mol.
1%, preferably 45 to 55 mol%, and the acid component is 60 to 40 mol%, preferably 55 to 45 mol%.
It is preferably 1%.

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

The binder resin used in the present invention may be a styrene-unsaturated carboxylic acid derivative copolymer, a polyester resin, a block copolymer thereof, a graft copolymer, monster,
Further, a mixture of a styrene copolymer and a polyester resin is preferable. The Tg (glass transition point) of the binder resin used in the toner of the present invention is preferably from 50 to 70C.

When a styrenic copolymer is used as the binder resin in the heat fixing toner, the effect of the wax is sufficiently exerted, and at the same time, the deterioration of the blocking resistance and the developing property, which are adverse effects due to the plastic effect, are reduced. To prevent this, the following toners are preferred.

In the molecular weight distribution of THF (tetrahydrofuran) soluble component of the toner by GPC, the weight average molecular weight (Mw) is preferably 2 × 10 ⁴ to 1 × 10 ⁶ , and more preferably 2 × 10 ⁴ to 8 × 10 ^5. Good, more preferably 2 × 1
0 ⁴ ~7 × 10 ⁵ is good. Number average molecular weight (Mn) is 2 × 1
0 ^{3 to} 1.5 × 10 ⁴ , preferably 3 × 10 ³ to
1.2 × 10 ⁴ is good, more preferably 3 × 10 ³ to 1 ×
10 ⁴ is good. Mw / Mn is preferably 3 to 200, preferably 3 to 150, and more preferably 3 to 100. Within these ranges, good fixability, developability and blocking resistance can be obtained.

When the weight average molecular weight (Mw) is larger than 1 × 10 ⁶ , the elasticity is increased and the fixing property is affected. On the other hand, when it is smaller than 2 × 10 ⁴ , good high-temperature offset resistance cannot be obtained.

When the number average molecular weight (Mn) is larger than 1.5 × 10 ⁴ , good fixing properties cannot be obtained, the fixing temperature rises, and the power consumption increases accordingly. In addition, in terms of productivity, deterioration in crushability leads to an increase in productivity cost. On the other hand, if it is smaller than 2 × 10 ^3, it is liable to be adversely affected by the plasticization effect due to the addition of wax, so that good developability and blocking resistance cannot be obtained.

When the value of Mw / Mn is larger than 200,
If the fixing ability is not good, and if it is smaller than 3, good hot offset resistance cannot be obtained due to the plasticizing effect of the addition of the wax.

In the present invention, the molecular weight distribution of the chromatogram of the toner by GPC is measured under the following conditions.

The column was stabilized in a heat chamber at 40 ° C., and THF was used as a solvent at this temperature.
(Tetrahydrofuran) at a flow rate of 1 ml / min.
Approximately 100 μl of the HF sample solution is injected for measurement. When measuring the molecular weight of a sample, the molecular weight distribution of the sample
Calculated from the relationship between the logarithm of the calibration curve prepared from several monodisperse polystyrene standard samples and the count number. As a standard polystyrene sample for preparing a calibration curve, for example, Tosoh Corporation or Showa Denko Corporation has a molecular weight of 1 × 10 ² to
It is appropriate to use about 10 ^{7 and} to use at least about 10 standard polystyrene samples. An RI (refractive index) detector is used as the detector. As the column, a combination of a plurality of commercially available polystyrene gel columns may be used. For example, Showex GPC manufactured by Showa Denko KK
KF-801,802,803,804,805,8
06,807,800P and TS manufactured by Tosoh Corporation
K Gel G1000H (H _XL ), G2000H (H
_{XL), G3000H (H XL)} . G4000H (H _XL ),
_{G5000H (H XL), C6000H (} H XL), G70
00H (H _XL ) and a combination of TSK guard column.

A sample is prepared as follows.

After placing the sample in THF and leaving it to stand for several hours, it is shaken sufficiently, and the THF is mixed well (until the sample is no longer united), and left still for 12 hours or more. At this time T
The time of leaving in HF is set to 24 hours or more.
Then, the sample processing filter (pore size 0.45μ)
m to 0.5 μm, for example, Mysholi Disc H-25
-5, manufactured by Tosoh Corporation, Exiclodisk 25CR, available from Germanic Science Japan, etc.) is used as a GPC sample. The sample concentration is adjusted so that the resin component is 0.5 to 5 mg / ml.

In the toner of 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, polyester, polyurethane, polyamide, epoxy resin, polyvinyl butyral, rosin, modified rosin, terpene resin, phenol resin, and a copolymer of two or more kinds of α-olefins may be used.

In the present invention, the following waxes are preferably contained in order to impart releasability to the toner. It is 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, and 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 these unsaturated groups, or And the like. In addition, alcohol wax, fatty acid wax, ester wax and natural wax are also used.

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

The amount of the wax added is preferably 0.5 to 10 parts by weight, more preferably 1 to 8 parts by weight, based on 100 parts by weight of the resin. In addition, 2
More than one type of wax may be added in combination.

The toner of the present invention contains a triphenylmethane compound as a charge control agent. Triphenylmethane compound is known as an excellent positively chargeable charge control agent, but when applied to a one-component toner, due to its high triboelectric chargeability, it has not been able to exhibit sufficient performance in all environments. Often.

In particular, blotches tend to occur in a low-humidity environment. However, when the toner is combined with a SUS sleeve having a slightly higher charging ability, or when the toner is regulated by a magnetic blade that magnetically regulates the toner layer, the blotch can be formed. Likely to happen. When the toner is magnetically regulated, the sleeve and the blade are normally in non-contact, so the blotch that has been electrostatically aggregated due to overcharging on the sleeve can only be resolved magnetically. If it is strengthened, the occurrence of blotches can be prevented, but there is a limit. It is effective to use a method in which the toner is regulated by an elastic blade or the like that comes into contact with the sleeve, because it is possible to mechanically loosen and eliminate the blotch, but in general, the elastic blade coat system has higher chargeability to the toner. Therefore, it cannot be said that it is generally strong against blotches.

In the present invention, by providing the triphenylmethane compound with a specific structure and particle size distribution, it is possible to maintain a high positive charging performance and to leak an appropriate charge from a leak site. As a result, it has been found that overcharging can be suppressed and stable toner chargeability can be maintained. In addition, the electroless plating sleeve such as Ni-P plating used in the present invention has a slightly inferior triboelectric charging performance as compared to SUS. Therefore, in combination with a conventional toner containing a charge control agent, there is a problem due to insufficient charging. However, in combination with the toner of the present invention, almost ideal charging performance can be exhibited without insufficient charging performance of the toner.

The triphenylmethane compound used in the present invention is a triphenylmethane pigment, a dye or a raked face thereof, and has a particle size distribution of 3.0 μm or less in an area-based particle size distribution measured by a centrifugal sedimentation method. %, Preferably 2.0 μm or less, more preferably 1.5 μm or less, and still more preferably 1.2 μm or less.

By having such a particle size, the particles can be uniformly dispersed in the toner, and the charging of the toner particles can be stabilized. If the 50% diameter exceeds 3.0 μm, the dispersion on the toner surface becomes non-uniform, the chargeability varies depending on the toner particles, and the toner as a whole becomes poorly charged, resulting in a decrease in density and fog. And the tendency increases under high humidity.

The triphenylmethane compound used in the present invention has a particle size distribution of 10%.
Good developability is obtained when the particle size exceeding μm is 3% or less, preferably 2% or less, more preferably 1% or less. When particles exceeding 10 μm in the particle size distribution of the triphenylmethane-based compound exceed 3%, free components not contained in the toner particles are liable to be generated, which hinders triboelectric charging of the toner particles, and furthermore, the Sleeve contamination that contaminates the triboelectric charging member may not be provided, and sufficient charge may not be applied to the toner, resulting in poor charging, image defects such as density reduction and fog. This adverse effect is particularly likely to occur under high humidity.

Further, the triphenylmethane compound used in the present invention preferably has crystalline particles, has high triboelectric charging ability, and can exhibit excellent developability. In the case of particles in an amorphous state, it is difficult to obtain sufficient charging ability, and may not be able to obtain sufficient charging ability as a charge control agent. In some cases, image defects such as failure to obtain images and fogging may be caused.

In the present invention, “crystalline” means CuKα
In X-ray crystal structure analysis using X-rays, 2θ (deg) 3 to 3
0 indicates that a sharp peak is observed.

According to the present invention, by using a specific triphenylmethane compound, it is possible to sufficiently compensate for the leakage of electric charge from the toner constituent material even under high humidity, and to use the specific triphenylmethane compound at low humidity to prevent the leakage from the charge site. High charge leakage is performed, and high charging ability can be controlled well. The “leak site” indicates a substance having a lower resistance than others among constituent materials exposed on the toner surface. In the present invention, among the triphenylmethane compounds, those represented by the following general formula (1) are most preferably used.

[0104]

Embedded image [In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , and R ⁶ each represent a hydrogen atom which may be the same or different, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl. Represents a group. R ⁷ , R ⁸ and R ⁹ each represent a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group which may be the same or different from each other. A ^- is an anion such as sulfate, nitrate, borate, phosphate, hydroxide, organic sulfate, organic sulfonate, organic phosphate, carboxylate, organic borate, and tetrafluoroborate. Is shown. ]

Specific examples of the compound represented by the general formula (1) are shown below, but do not limit the present invention in any way.

[0106]

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[0107]

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[0108]

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[0109]

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[0110]

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[0111]

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The lake formation of the triphenylmethane compound is carried out by a known method. For example, an aqueous solution of a lake agent is added to an aqueous solution of triphenylmethane compound in acetic acid to precipitate the lake pigment. Alternatively, the extender is suspended in an aqueous acetic acid solution of a triphenylmethane compound, and then an aqueous solution of a laker is added to precipitate the lake pigment on the surface of the extender. Examples of the laker include water-soluble salts of phosphotungsten molybdic acid, phosphotungstic acid, phosphomolybdic acid, and water-soluble salts containing complex anions such as ferrocyan and ferricyan. Organic acid salts can also be used as the laker, but for example, gallic acid lakes do not have very good charging characteristics. This is considered to be due to the fact that, in the organic acid lake, the compatibility between the resin and the lake compound is good, so that the properties of the resin having poor charging characteristics appear remarkably.

As for the triphenylmethane compound used in the present invention, fine crystalline particles can be obtained by controlling the crystallization method after synthesis or by recrystallization. In addition, a desired particle size can be obtained by operations such as pulverization and classification.

In the present invention, the particle size distribution is measured by the following method based on the liquid phase sedimentation method.

5 to 10 mg of a sample was added to 50 ml of a water / ethanol mixture of 10% ethanol, dispersed for 5 minutes in an ultrasonic washer, and then subjected to isoacceleration centrifugation sedimentation measurement (16 s ^-1 ) to measure ⁰ to 10 μm on an area basis. Particle size distribution and average diameter (50% diameter) at 1 μm intervals assuming that the diameter exceeds 10 μm
Is measured. As a measuring instrument, for example, CAPA-700
(Manufactured by Horiba) can be used.

The X-ray crystal structure analysis shows that the characteristic X-ray
It is determined by an X-ray diffraction spectrum using α-rays as a radiation source. As the measuring device, for example, a powerful full-automatic X-ray diffractometer MXP18 (manufactured by Mac Science) can be used. When the sample is crystalline, a sharp peak is observed, and when the sample is amorphous, a broad halo is obtained.

As a method for incorporating the triphenylmethane compound used in the present invention into a toner, there are a method of adding the compound to the inside of the toner and a method of externally adding the compound. As the amount of use of these charge control agents, the type of binder resin, the presence or absence of other additives,
It is determined by the toner production method including the dispersion method, and is not specifically limited, but is preferably 0.1 to 10 parts by weight, more preferably 0.1 to 10 parts by weight, based on 100 parts by weight of the binder resin. It is used in the range of 1 to 5 parts by weight. When externally added, 0.01 parts by weight based on 100 parts by weight of resin.
The amount is preferably from 10 to 10 parts by weight, particularly preferably, mechanochemically fixed to the surface of the toner particles.

The triphenylmethane compound used in the present invention can be used in combination with a conventionally known charge control agent.

As the colorant that can be used in the toner of the present invention, any suitable pigment or dye can be used. Examples of toner colorants include pigments such as carbon black, aniline black, acetylene black, naphthol yellow, hansa yellow, rhodamine lake, alizarin lake, bengara, phthalocyanine blue, and indanthrene blue. These are used in amounts necessary and sufficient to maintain the density of the fixed image, and are preferably added in an amount of 0.1 to 20 parts by weight, preferably 0.2 to 10 parts by weight, based on 100 parts by weight of the resin. 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 weight, preferably 0.3 to 1 part by weight, per 100 parts by weight of the resin.
The addition amount of 0 parts by weight is good.

The toner of the present invention can be used as a magnetic toner by further containing a magnetic material. In this case, the magnetic material can also serve as a colorant. In the present invention, as a magnetic material contained in the magnetic toner, iron oxides such as magnetite, maghemite, and ferrite are used, and lithium, beryllium, boron, magnesium, aluminum, silicon, phosphorus, calcium, scandium, titanium, and vanadium are used. , Chromium, manganese,
Cobalt, nickel, copper, zinc, germanium, arsenic,
Selenium, strontium, barium, zirconium, molybdenum, tungsten, palladium, silver, gallium,
Magnetic metal oxides containing elements such as indium, tin, lead, antimony and bismuth, and magnetic iron oxides containing these elements are used. Preferably, magnetite is used, and one containing simultaneously the above-mentioned elements other than iron is also used.

The magnetic substance used in the present invention has a BET specific surface area of 1 to 40 m ² /
g, more preferably 3 to ²⁰ m ² / g,
Preferably, it is 5 to 15 m ² / g. The saturation magnetization of the magnetic material is 40 to 150 at a magnetic field of 795.8 kA / m.
Am ² / kg is preferred, and more preferably 50 to 12
0Am ² / kg is well desirably 60~100Am ² /
kg is good. The residual magnetization is 795.8 kA /
The magnetic field is preferably ² to 50 Am ² / kg, more preferably 3 to 20 Am ² / kg, and more preferably 4 to ²⁰ Am ² / kg.
15 Am ² / kg is good. Further, the coercive force of the magnetic material is 3.0 to 16.0 k at a magnetic field of 795.8 kA / m.
A / m is preferred, and more preferably 4.5 to 12.0
kA / m is good, and desirably 6.0 to 10.0 kA / m.
Is good. The average particle size of the magnetic material is 0.05 to 0.
5 μm is preferred, and more preferably 0.1 to 0.3 μm.

The amount of the magnetic substance contained in the toner is preferably 20 to 200 parts by weight, more preferably 30 to 150 parts by weight, and more preferably 40 to 120 parts by weight, based on 100 parts by weight of the binder resin. Department is good.

In the present invention, the particle diameter of the magnetic substance can be obtained by observation with a transmission electron microscope and a scanning electron microscope. The magnetic properties of the magnetic material were measured using a vibrating sample magnetometer V
It can be measured by SM-3S-15 (manufactured by Toei Industry Co., Ltd.) or the like. Further, the specific surface area can be determined by measuring by nitrogen gas adsorption using a specific surface area measuring device Autosorb 1 (manufactured by Yuasa Ionics) according to the BET method and calculating by the BET multipoint method.

In the case of a magnetic toner, the toner has a true specific gravity of 1.
It is about 4 to 1.7 g / cm ³ , which is mainly determined by the content of the magnetic substance. Those having a low specific gravity are liable to be developed, so that the problem of fogging is likely to occur, and those having a high specific gravity are liable to have a low density.

The above description regarding the magnetic substance is, of course, the case where the present invention is applied to a magnetic toner, and the present invention can be applied to a non-magnetic toner using no magnetic substance. In this case, only the colorant is used.

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

As the function of silica, in addition to improving the fluidity, the silica has a function of reducing friction by interposing between the toner particles and the sleeve (improving durability), and also prevents aggregation of toner particles and makes contact with the sleeve. This is because it also has a role of promoting the replacement of the toner that is not in contact with the existing toner (improving the charging stability and the developing property).

The fine silica powder used in the present invention is BE
Those having a specific surface area of 30 m ² / g or more (particularly 50 to 400 m ² / g) by nitrogen adsorption measured by the T method give good results. It is preferable to use 0.01 to 8 parts by weight, preferably 0.1 to 5 parts by weight of silica fine powder with respect to 100 parts by weight 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, A silane coupling agent having a functional group,
It is also preferable that the composition is treated with another treating agent such as an organosilicon compound or a combination of various treating agents.

As other additives, lubricant powders such as Teflon powder, zinc stearate powder and polyvinylidene fluoride powder are preferable, and polyvinylidene fluoride is particularly preferable. Fluorine-containing polymers such as polyvinylidene fluoride,
Although the reason is not clear, it has a function of reducing the release of silica adhering to the toner from the toner, and as a result, there is an effect of increasing the charging stability.

Alternatively, abrasives such as cerium oxide powder, silicon carbide powder and strontium titanate powder, among which strontium titanate is preferable. Strontium titanate or the like plays a role of an abrasive for the drum, and as a result, has an effect of polishing and removing toner adhering to the drum in a filming manner.

Alternatively, for example, a fluidity-imparting agent such as a titanium oxide powder or an aluminum oxide powder, particularly a hydrophobic agent is preferable. A small amount of a caking inhibitor, a conductivity imparting agent such as a carbon black powder, a zinc oxide powder, an antimony oxide powder, a tin oxide powder, and the like, and fine particles of white and black having opposite polarities can also be used as a developing property improver.

To produce the toner of the present invention, a binder resin,
Charge control agent, wax, pigment or dye, magnetic material, and other additives as necessary, Henschel mixer, after sufficiently mixing with a mixer such as a ball mill, heating roll,
While melt-kneading using a hot kneader such as a kneader or extruder to make the resins compatible with each other, the pigments, dyes, and magnetic materials are dispersed or dissolved, and after cooling and solidifying, pulverization and classification are performed, and the present invention is performed. Can be obtained.

Further, as another toner producing method,
A polymerization method in which a predetermined material is mixed with a monomer to constitute a binder resin to form an emulsified suspension, and then polymerized to obtain a toner,
Further, in a so-called microcapsule toner composed of a core material shell material, a method of including a predetermined material in a core material or a shell material, or both, or a method of dispersing a constituent material in a binder resin solution and then spraying A method of obtaining a toner by drying can be applied.

Further, if necessary, desired additives are sufficiently mixed by a mixer such as a Henschel mixer to obtain the developer of the present invention.

In the following examples, details of the device side of the present invention and the effects of the present invention will be specifically shown.

[0137]

(Embodiment 1) FIG. 1 schematically shows an image forming apparatus according to this embodiment. Reference numeral 12 denotes a latent image holding member which rotates in the direction of arrow A, which is usually an electrophotographic photosensitive member, here a photosensitive drum. Reference numeral 9 denotes a well-known electrostatic latent image forming unit which performs pre-exposure for removing residual charge on the drum, a neutralizing member such as a static eliminator and a primary charger for newly charging the drum, and image exposure for forming an electrostatic latent image. Device. Reference numeral 13 denotes a developing device according to the present invention which rotates in the direction of arrow B to visualize the latent image, and 10 transfers the visualized toner image on the photosensitive drum to the transfer material and simultaneously separates the transfer material from the drum. A known transfer / separation unit 11 is a known cleaning unit for cleaning residual toner on the drum. As described in detail later, a magnetic toner in which magnetic particles are dispersed in a resin is used as the developer.

An electrostatic latent image is formed on the photosensitive drum 12 by the latent image forming section 9. Further, the photosensitive drum rotates in the direction of arrow A and reaches the developing device 13. FIG.
A developing container 7 containing a magnetic toner as a one-component developer, conveying / stirring means 8 for feeding the toner from the developing container 7 to the vicinity of the sleeve and mixing and stirring the new and old toners, and a fixed magnet 14 and a non-magnetic sleeve 5 that rotates in the direction of arrow B. The sleeve 5 conveys the toner to the developing unit facing the drum 12,
The toner is developed to the drum side by the action of an electric field (and a magnetic field in the case of development of a magnetic toner) near the closest part to the drum.

In this case, the thickness of the toner layer on the sleeve 5 is regulated by a magnetic blade 6 provided opposite to the magnetic pole N1 of the magnet 14 with the sleeve 5 interposed therebetween and in close contact with the sleeve.

At the developing position where the sleeve and the drum are opposed to each other, the toner rises due to the developing pole N2, and the toner flies due to the electric field between the latent image on the drum 12 and the sleeve and is pulled back by the action of the electric and magnetic fields. Visualize the image. At this time, the developing bias voltage is applied to the sleeve 5 from the power supply 15 so that the toner can easily fly. This is an alternating bias in which a DC bias is superimposed. As a result, the toner flying from the sleeve 5 toward the drum 12 repeatedly adheres to and separates from the drum. When the drum finally passes through the developing unit, the toner is applied to the drum in accordance with the potential of the latent image. Adhere to.

Thereafter, the toner on the drum is transferred to the transfer material in the transfer unit 10 and is permanently fixed to the transfer material in a fixing unit (not shown). On the other hand, the remaining toner on the drum is cleaned by the cleaning unit 11 to prepare for the next latent image formation.

The general conditions for image formation are as follows.

The photosensitive member is an a-Si drum having a diameter of 108 mm, and the potential of the dark part is +400 V and the potential of the bright part is +50 V as the latent image conditions.

Further, the copying speed is 60 sheets / minute in A4 size, and the rotation speed of the photosensitive member is 300 mm / sec.

At this time, the conditions for development (assuming that digital reversal development is performed) are as follows.

The developing sleeve (detailed later) has a diameter of 32 m.
m, a positive toner having the same polarity as the charging polarity of the drum is accommodated for digital reversal development, and the magnetic force of the magnet fixed inside the sleeve is N1 pole on the surface of the sleeve: 100
0G, S1 pole: 1000G, N2 pole: 1000G, S2
Pole: 550G, N2 pole: 600G, S2 pole: 1050G
It is. The developing pole is an N2 pole and faces the drum, and the cut pole is an N1 pole and faces a magnetic blade having a thickness of 1 mm.
The closest gap between the sleeve and the drum was 200 μm, and the gap between the sleeve and the blade was 240 μm. The rotation speed of the sleeve was 1.9 times that of the photoconductor. The developing bias is such that the AC component has a peak-to-peak voltage of 1.0 kVpp, a frequency of 2.7 kHz, and a duty ratio of 40.
% Of the AC voltage and a DC voltage of 280 V as a DC component are applied to the developing sleeve.

A more detailed description of the digital copier mentioned here will be described below.

The experiment was conducted on a digital machine using an a-Si drum as the photosensitive drum. After the surface was charged to +400 V, image exposure was performed so that the image area became +50 V.

Image exposure is generally performed by laser or LED, and here, a visible light laser of 680 nm is used.

Although a scanner section for reading the original and an image processor for creating image data are not shown, the reflected light from the original image formed on the CCD of the scanner is A / D converted to 600 dpi, 8 bits (256 gradations). ) Is converted to a luminance signal of the image and sent to the image processor. The image processor performs a well-known brightness-density conversion (Log conversion), converts the image signal into a density signal, and if necessary, performs filtering such as edge enhancement, smoothing, and removal of high-frequency components, and then performs density correction. After performing the processing (so-called γ conversion), the data is binarized (1 bit) through a binarization processing such as an error diffusion method or a screen processing using a dot concentration type dither matrix. Of course, the latent image may be formed by driving the laser by a well-known PWM (pulse width modulation) method or the like with 8 bits as it is, but binary imaging is the mainstream in recent years from the viewpoint of easy handling of image data. It is. Naturally, since the data is compressed to 1/8, for example, in a machine having a page memory of about A3 document or a copying machine having an image server for storing a large amount of image data, the memory is largely reduced and the cost is reduced. Leads to down.

Thereafter, the image signal is sent to the laser driver, and the laser is driven in accordance with the signal (the PWM modulation method is used for an 8-bit image, and the laser is turned on / off for 1 bit). The laser beam is irradiated on the drum via a collimator lens, a polygon scanner, an fθ lens, a folding mirror, dustproof glass, and the like. The spot diameter on the drum is 1 pixel at 600 dpi = 4
An image is formed on the drum at a spot size of about 55 μm, which is slightly larger than 2.3 μm, and the image portion is formed as described above.
The charge is removed to about +50 V to form an electrostatic latent image.

Next, the developing sleeve and toner used in the present developing device will be described in detail.

First, regarding the developing sleeve 5 shown in FIG.
4 is a magnet roller included in the sleeve, 5
Reference numeral 1 denotes a substrate, which is an aluminum alloy (for example, A606)
3, a thickness of 0.65 mm and a diameter of 32 mm). Reference numeral 52 denotes a plating layer of electroless Ni-P plating, and has a thickness of 20 μm. Aluminum has Vickers hardness Hv ≒ 50-15
At about 0, the aluminum sleeve after the centerless polishing was blasted with spherical particles. As the treating agent, spherical blast abrasive grains (smooth surface, spherical or spherical flat particles are preferable) are used, and glass beads of # 100 to # 800 are used (# 600 was used in this case). The blast treatment agent was applied to four sleeves each having a diameter of 150 mm from four nozzles having a diameter of 150 mm from four directions with respect to the sleeve rotating at 0.6 s ^-1.
Spraying was performed at 0 ^-1 Mpa for 9 seconds (for a total of 36 seconds). The nozzle is blasted by moving it in the shape of "C" with respect to the axis of the sleeve. After the above-mentioned sand blasting, the sleeve is cleaned and then dried in a cleaning step.

Here, the sleeve base material is Vickers hardness H
v is preferably 50 to 150, and a smooth blast surface with few cracks can be obtained.

The general steps of the plating method are as follows: after cleaning and degreasing the surface of the sleeve, pretreatment is performed by zincate treatment, and then electroless plating of Ni-P containing 10% P (also referred to as chemical plating) is performed. gave. Here, the plating layer is about 2
It was formed to about 0 μm.

In this case, since the heat treatment in the post-process is not performed, the hardness is about 450 in terms of Hv in the hardness of ordinary electroless Ni-P plating, but is sufficient in terms of durability as a developing sleeve. Alternatively, the hardness can be increased to Hv = about 1000 or more by heat aging as needed, but the eccentricity (warpage) of the sleeve increases depending on the thickness of the sleeve. It is.

Regarding hardness and abrasion resistance, Ni-P plating of Hv = 450 was used, so that SUS316 (Hv = Hv = 450) was used.
200).

The final values of the roughness of the sleeve, such as Ra and Rz, are as shown in Table 2 below. The AL (after blasting and before plating) data is also provided for reference.

[0159]

[Table 2] * Sm: average mountain interval

From Table 2, it can be seen that the roughness before and after plating does not change significantly because of the electroless plating. In general, electroplating is applied preferentially to the convex part where the concentration of electrolysis is preferentially applied to the rough surface, so plating is easy to adhere only to the convex part and the plating thickness becomes thick, so a uniform plating layer can be formed. Instead, the roughness changes (slightly) before and after plating. On the other hand, the electroless plating is a chemical plating, so that a plating layer can be uniformly and accurately formed regardless of the uneven surface.

Examples of the type of electroless plating include, in addition to the above-described electroless Ni-P plating, electroless Ni-B plating, electroless Cr plating, and the like. These are SU
The chargeability is slightly lower than that of S. And as the physical properties of the sleeve surface, there is a magnet roll inside the sleeve,
In the case of magnetic one-component development using a magnetic toner, it is desirable that the toner is non-magnetic. Therefore, electroless Ni-P plating, electroless Ni-B plating, and electroless Pd-P plating are preferable.

In the present invention, the plating thickness is 1 to 50 μm.
m, preferably 5 to 25 μm, more preferably 5 to 20 μm.
μm is good.

Although the sleeve of the present invention is plated to fill small cracks on the surface of the sleeve and thereby prevent the occurrence of sleeve contamination, the plating thickness is 1 μm.
If the thickness is less than 50 mm, the effect of preventing sleeve contamination is not exhibited, and if the plating thickness exceeds 50 μm, it becomes difficult to form a uniform plating layer. The magnetic field of the internal magnet may be disturbed.

When the ten-point average roughness Rz is 2 to 15 μm and / or the center line average roughness Ra is 0.3 to 1.5 μm, a good balance between toner transportability and sleeve contamination prevention is obtained. Can be.

In addition, the blast particles are # 100 to #
When the spherical particles have a particle diameter of 800, the above-mentioned surface shape can be easily obtained.

Regarding the Ni-P and Ni-B plating described above, Ni is ferromagnetic by itself, but becomes amorphous and becomes non-magnetic when combined with phosphorus or boron during electroless plating. At that time, the content of phosphorus in the plating is about 5 to 15%, and the content of boron is about 2 to 8%.

If the content of phosphorus in the plating is less than 5% or the content of boron in the plating is less than 2%, the magnetic field of the magnet inside the sleeve is disturbed because the plating layer shows magnetism.

If the phosphorus content in the plating exceeds 15%, or if the boron content in the plating exceeds 8%, it is difficult to form a normal plating layer.

The plating may be performed on the entire surface of the sleeve, but it is also possible to perform masking as a pre-plating process and then perform plating in a mesh shape.

In the process of manufacturing the sleeve, a magnet may be incorporated after plating the entire tube of the sleeve and the sleeve shafts (flanges) at both ends may be incorporated, or plating may be performed after the magnet and the flange are assembled. Good. When plating with a magnet inside, it is necessary to thoroughly control the bath so that impurities of the magnetic substance are not mixed in the plating bath.

Next, the magnetic toner used in the first embodiment of the present invention will be described as toner (A).

The composition and manufacturing method of the toner used for explaining the above problems are also described as the conventional toner (a).

Toner (A): 80 parts by weight of styrene-butyl acrylate copolymer (Mw = 2.4 × 10 ⁵ , Mn = 7.2 × 10 ³ , Mw / Mn = 33.3) ・ Styrene-butadiene 20 parts by weight of copolymer (Mw = 2.2 × 10 ⁵ , Mn = 1.4 × 10 ⁴ , Mw / Mn = 15.7) ・ 90 parts by weight of magnetite ・ 2 parts by weight of triphenylmethane compound (structure; specific) Example (1), 50% diameter = 0.81 μm, 10 μm or more: 0.0%, X-ray diffraction peak (2θ): 6, 12, 14, 18.5 deg Other sharp peaks exist) Low molecular weight ethylene-propylene copolymer 4 parts by weight

After the above materials were sufficiently premixed with a Henschel mixer, they were melted and kneaded by a twin-screw extruder set at 130 ° C. After cooling the obtained kneaded material, it is roughly pulverized by a cutter mill, finely pulverized by a pulverizer using a jet stream, and further classified by using a multi-divided classifier utilizing the Coanda effect. Thus, a classified fine powder (toner particles) having a weight average particle diameter of 6.0 μm was obtained.

100 parts by weight 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 (amine equivalent 830, viscosity at 25 ° C. 70 mm ² ) per 100 parts by weight
/ S) 0.8 parts by weight of hydrophobic silica treated with 17 parts by weight was added, mixed with a Henschel mixer, and the opening was 150 μm.
and decorated with a mesh of m to obtain toner (A).

In the molecular weight distribution of the THF-soluble component of the toner (A) by GPC, Mw was 1.8 × 10 ⁵ , and Mn was Mn.
Was 1.0 × 10 ⁴ and Mw / Mn was 18.

The toner (a) used in the conventional example is as follows.

Toner (a): 100 parts by weight of styrene-butyl acrylate copolymer (Mw = 2.4 × 10 ⁵ , Mn = 7.2 × 10 ³ , Mw / Mn = 33.3) 90% by weight of magnetite Part: 2 parts by weight of nigrosine; 4 parts by weight of low molecular weight ethylene-propylene copolymer: weight average particle diameter: 6.0 μm Toner (a) was obtained in the same manner as toner (A) using the above materials and formulation. .

In the molecular weight distribution of the THF-soluble component of the toner (a) by GPC, Mw was 1.6 × 10 ⁵ , Mn was
Was 7.0 × 10 ³ and Mw / Mn was 22.9.

In the conventional toner (a), only the styrene-acryl copolymer was used as the binder, whereas in the present invention, the styrene-acryl copolymer was used as the binder for the toner (A) in the styrene-butadiene copolymer. Coalescence was added. Nigrosine was used as the charge control agent of the conventional toner (a), whereas triphenylmethane was used as the charge control agent of the toner (A).

The weight average particle diameter of the toner is 4 to 10 μm (preferably 5 to 9 μm). If the weight average particle diameter is less than 4 μm, it is difficult to control the toner. In particular, the density of solid black tends to be low. If it exceeds, the resolution of the thin line is inferior. Here, those having a weight average particle diameter of 6 μm were used.

The weight average particle size of the toner of the present invention is measured using a Coulter Multisizer (manufactured by Coulter), and the electrolyte is measured using ISOTON II (manufactured by Coulter). An aperture tube having a 100 μm aperture is used. As a measuring method, the electrolytic solution 100 to
0.1 to 5 m of a surfactant as a dispersant in 150 ml
and 2 to 20 mg of the measurement sample. The electrolyte in which the sample is suspended is subjected to a dispersion treatment for about 1 to 3 minutes by an ultrasonic disperser, and the volume and the number are measured by the measuring device to calculate a weight average diameter.

[Experiment 1] An experiment was conducted using the developing device and the toner (A) in the image forming apparatus described above.

The toner on the sleeve has a sufficient toner coat amount (about 0.8 mg / cm ² ) and a toner charge amount (14 m
C / kg), no initial toner coat failure, and A4, 100,000-sheet continuous copy test (print rate 6
% Original) in three environments, the decrease in density was about 0.1 even in a high-humidity environment (about 1.4 at the beginning), and almost no image deterioration was observed.

The effect of the improvement of the toner in the case of using the Ni-P plating sleeve as described above will be described with reference to Table 1 of the post-durability density and the post-durability tribo shown in the conventional problems as follows. become.

Table 3 shows that Ni-P plating sleeves were used.
This shows the effect when the toner prescription is changed.

[0187]

[Table 3]

As can be seen from Table 3, there is no sleeve contamination because both use Ni-P plated sleeves.
In such a situation, the toner using the toner (A) had a higher triboelectricity than that using the toner (a), and the change in the toner particle size after the endurance did not differ between the two.
The toner (A) has a smaller tribo change with respect to the toner particle diameter than the toner (a). Therefore, there is no decrease in the density under a high-humidity environment, which has conventionally been a problem in the density after durability. In addition, there was no occurrence of blotting at N / L when the tribo was high. However, this is because Ni-P plating sleeves and the like originally had a slightly inferior chargeability as compared with SUS and tribo was not too high. Conceivable. FIG. 3 is a graph of Table 3 as shown in FIG. 11 of the conventional example.

As a result, it was confirmed that, over the entire environment, good image quality with no occurrence of blotches and no pitch unevenness and high density without sleeve contamination can be maintained over 100,000 durable sheets.

Here, heat aging (315 ° C., 1
When a similar test was performed using the Ni-P plated sleeve that had been subjected to the above-mentioned time, good results equivalent to those described above were obtained. When the Ni-P plating sleeve is heat-aged, the hardness increases and the durability is further improved. Here, Hv was about 920. Heat aging slightly recovered the magnetic properties of Ni and shielded the magnetic field of the internal magnet. However, the degree was very small, 1 to 2%, and no adverse effect was observed.

[Comparative Test Example with SUS Sleeve] A case where the above toners (A) and (a) are used for a SUS sleeve will be described below for reference.

Table 4 in addition to Table 1 which describes post-durability density and post-durability tribo when toner (a) is used in a SUS sleeve due to conventional problems.

[0193]

[Table 4]

As can be seen from Table 4, when the toner (A) was used, especially under an N / L environment, a blotch occurred due to local excessive charging, and the toner coat became uneven, and the image unevenness as it was. Therefore, the durability evaluation could not be performed. Blotches were also seen in a minor but N / N environment.

In the case of H / H, no blotch occurred and the density after durability could be maintained higher than that of the conventional toner (a). However, this is not the same as the degree of sleeve contamination itself, but the degree of contamination does not change. This is due to the high tribo after durability including contamination. FIG. 4 is a graph of the environment in Table 4 and the tribo after the endurance in the same manner as in FIG.
It is.

As described above, when the SUS sleeve was used, even when the toner (A) was used, the same effect as when the toner (A) was used for the Ni-P plating sleeve was not found.

The SUS sleeve used here was obtained by blasting stainless steel (SUS 316) with spherical glass beads having a grain size of # 600. The blast pressure was set higher than that of aluminum in order to make the roughness almost uniform, and blasting was performed. As a result, a sleeve having a surface roughness as shown in Table 5 was obtained.

[0198]

[Table 5] * Sm: average mountain interval

[Example 2 of Actual Test] An example in which the same developing device as that of Example 1 of the actual test is applied to an OPC drum negative charging type analog copying machine will be described below. The image forming conditions are described only in the portions different from the actual test example 1.

The copying speed is 30 sheets / minute at A4, and the rotation speed of the photosensitive member is 180 mm / sec.

An OPC drum having a diameter of 30 mm was used as the photosensitive drum, and the dark potential of the photosensitive drum (image potential in the case of analog) was -700 V, and the potential of the exposed portion (non-image portion in the case of analog) was -150 V. , The developing sleeve having a diameter of 20 mm (Ni-B plating 10 μm)
m: B6%), and the magnetic force of a magnet roller having four poles fixed inside the sleeve is S1 pole: 1000 G, N1 pole: 800 G, S2 on the surface of the sleeve.
Pole: 550G, N2 pole: 750G. Development pole is S1
The pole is opposed to the drum, and the cut pole is N1 pole and faces a magnetic blade having a thickness of 1 mm.

The gap between the photosensitive drum and the sleeve is 300
μm, and an AC bias (Vpp = 1.5
kVpp, f = 2.7 kHz, duty ratio = 50%), and a DC component of -250
V is superimposed.

The toner (A) was used.

Under the above conditions, the toner transport amount and the charge amount are almost the same as in the actual test 1, and there are no initial blotches, and there is no problem of image density reduction and deterioration in 100,000 sheets of the continuous copy test. Was confirmed.

(Embodiment 2) Here, using the same machine and toner (A) as in the actual test example 1 of Embodiment 1 described above, the plating material for the developing sleeve was not electroless Ni-P plating, but Electrolytic Cr plating (5 μm) was used, which was different.

As the toner, the following toner (B)
It has been confirmed that there is no problem with using.

Toner (B): 80 parts by weight of styrene-butyl acrylate copolymer (Mw = 2.4 × 10 ⁵ , Mn = 7.2 × 10 ³ , Mw / Mn = 33.3) ・ Styrene-butadiene 20 parts by weight of divinylbenzene copolymer (Mw = 2.0 × 10 ⁵ , Mn = 9.0 × 10 ³ , Mw / Mn = 22.2, THF insoluble matter = 20% by weight) ・ 90 parts by weight of magnetite Triphenylmethane compound 2 parts by weight (Structure; specific example (1), 50% diameter = 1.35 μm, 10 μm or more: 0.8%, X-ray diffraction peak (2θ): 6, 12, 14, 18.5 deg)・ A low molecular weight ethylene-propylene copolymer 4 parts by weight ・ ・ ・ Weight average particle diameter 7.0 μm Using the above materials, toner (B) was prepared in the same manner as toner (A). Obtained.

In the molecular weight distribution of the THF-soluble component of the toner (B) by GPC, Mw was 1.6 × 10 ⁵ , Mn was
Was 8.0 × 10 ³ and Mw / Mn was 20.

Also in Example 2, it was confirmed that the initial image was at a level having no problem, and that the density decrease at the time of 100,000 sheets of the continuous copy test was as small as about 0.1.

Further, the continuous copying test is continued and 100
When the scraping of the sleeve at the time of 10,000 sheets was measured (here, the thinning from the initial diameter was determined as the scraping of the sleeve), it was confirmed that the average was very small, less than 1 μm.

This is presumably because the electroless Cr plating has a higher hardness than the electroless Ni-P plating of Example 1. Normally, Ni-P plating has a Hv of about 450 (unless annealing is performed), whereas electroless C
The r plating is as high as Hv ≒ 600. For reference, the amount of scraping by Ni-P plating in Example 1 is about 1.5 μm on average, and the amount of scraping by electroless Cr plating is about half as small, and the service life of the sleeve can be extended.

Embodiment 3 Here, an example in which the present invention is applied to a so-called elastic blade coat developing device as a developing device will be described. FIG. 5 shows a developing device of the present embodiment, which is almost the same as the developing device of FIG. 2 (the developing device of the first embodiment). In this embodiment, the magnetic blade 6 in FIG. Has been replaced.

The copying speed is 10 sheets / minute at A4, and the rotation speed of the photosensitive member is 60 mm / sec.

The present invention was applied to a regular development type personal copying machine using OPC having a diameter of 30 mm as a photosensitive drum. The surface of the drum is charged to −600 V, and the image area is reduced by −1 by image exposure.
The charge was removed to 00V.

Developing sleeve (Pd-P plating 25 μm:
P7%) indicates that the magnetic force of a magnet roller having a diameter of 18 mm and having four poles fixed inside the sleeve is S1 pole: 900 G, N1 pole: 400 G, S2 on the sleeve surface.
Pole: 300G, N2 pole: 800G. Development pole is S1
The following elastic blades are in contact with the drum at the pole and the cut pole at the N1 pole at a position 10 degrees downstream of the N1 pole position in the sleeve rotation direction.

The gap between the photosensitive drum and the sleeve is 300
μm, and an AC bias (Vpp = 1.5
kVpp, f = 2.2 kHz, Duty ratio = 50%), and a DC component of −200
V is superimposed. In the case of Pd-P plating, the content of P is preferably 2 to 15%.

When the content of P in the plating is less than 2%,
The plating layer shows magnetism, and the magnetic field of the magnet inside the sleeve is disturbed. If the P content in the plating exceeds 15%, it becomes difficult to form a normal plating layer.

The elastic blade is made of silicone rubber and is brought into contact with the contact pressure at a light pressure of about 0.12 N per 1 cm of contact pressure, so that the elastic blade is not the edge but the antinode. The contact nip at this time was about 1 mm.

As the toner, the following toner was used.

Toner (C): 80 parts by weight of styrene-butyl acrylate copolymer (Mw = 2.4 × 10 ⁵ , Mn = 7.2 × 10 ³ , Mw / Mn = 33.3) ・ Styrene-butadiene 20 parts by weight of copolymer (Mw = 2.2 × 10 ⁵ , Mn = 1.4 × 10 ⁴ , Mw / Mn = 15.7) ・ 90 parts by weight of magnetite ・ 2 parts by weight of triphenylmethane compound (structure; specific) Example (1), 50% diameter = 1.43 μm, 10 μm or more: 1.0%, X-ray diffraction peak (2θ): broad halo around 19 deg) ・ 4 parts by weight of low molecular weight ethylene-propylene copolymer ... Weight average particle diameter 7.0 μm Using the above materials, a toner (C) was obtained in the same manner as the toner (A).

In the molecular weight distribution of the THF-soluble component of the toner (C) by GPC, Mw was 1.7 × 10 ⁵ , Mn was
Was 1.0 × 10 ⁴ and Mw / Mn was 17.

The toner (C) is slightly inferior to the toner (A) in developability because the charge control agent triphenylmethane is amorphous based on the toner (A). As compared with the case where the cutting system is used, the charge amount of the toner can be increased because the elastic blade system of the present invention is used, and as a result, the density is not inferior to the actual test example 1.

Then, the toner transport amount (0.6 mg / cm ²⁾
) And the charge amount (about 18 mC / kg) are good, and the initial image is further improved in terms of image quality because the charge amount is higher than that in Example 1, and furthermore, the charge amount is high because of the contact elastic blade. Also, a continuous copying test was performed after confirming that no blotch occurred and that there was no problem. In the case of the elastic blade coat as in the present embodiment, the sleeve contamination may occur earlier because the elastic blade abuts on the toner on the sleeve. It was confirmed that there was no problem with regard to the density reduction and deterioration of the image.

[0224] In addition, the sleeve is easily scraped because the elastic blade is in contact with the sleeve.
The amount of shaving was small because the sleeve was hard because of the plating (it was about 2.5 μm at 10,000 sheets).
Therefore, if necessary, it is possible to provide a toner peeling / applying roller for preventing sleeve ghost from being brought into contact with the sleeve on the upstream side of the elastic blade.

Further, a test was conducted using a toner (D) as described below for a non-magnetic one-component developing device having a magnet in the sleeve with a developing device configuration substantially the same as described above. Similar good results were obtained.

Toner (D): 80 parts by weight of styrene-butyl acrylate copolymer (Mw = 2.4 × 10 ⁵ , Mn = 7.2 × 10 ³ , Mw / Mn = 33.3) ・ Styrene-butadiene 20 parts by weight of copolymer (Mw = 2.2 × 10 ⁵ , Mn = 1.4 × 10 ⁴ , Mw / Mn = 15.7) ・ Carbon black 5 parts by weight ・ Triphenylmethane compound 2 parts by weight (Structure; Specific example (1), 50% diameter = 0.81 μm, 10 μm or more: 0.0%, X-ray diffraction peak (2θ): 6, 12, 14, 18.5 deg Other sharp peaks exist) 4 parts by weight of low molecular weight ethylene-propylene copolymer: weight average particle diameter 8.0 μm Toner (D) is a non-magnetic toner using carbon black as a colorant instead of the magnetic substance of toner (A) It is.

In the molecular weight distribution of the THF-soluble component of the toner (D) by GPC, Mw was 1.7 × 10 ⁵ , Mn was
Was 9.0 × 10 ³ and Mw / Mn was 18.9.

(Embodiment 4) In the same test as in Embodiment 1, the electroless Ni-P plating was applied to the sleeve in the same manner as in the sleeve of Embodiment 1, but the plating layer thickness was different. A sleeve provided with a plating thickness of 30 μm and a plating thickness of 3 μm was used.

Although it has been described above that plating is effective for contamination of the sleeve by filling the minute cracks, it is useless in terms of cost to increase the thickness more than necessary. By forming a necessary and sufficient plating thickness, it is possible to minimize the cost while improving the performance.

When a sleeve (30 μm) with a thicker Ni—P plating was used, the same machine and toner (A) as in the actual test example 1 of Example 1 were used, but the sleeve life was further improved. There was no problem even at 500,000 sheets durability.

When a sleeve (3 μm) with a reduced Ni—P plating thickness was used, the same machine and toner (A) as in the actual test example 1 of Example 1 were used, but an image having no practical problem was obtained. Some sleeve contamination was observed in the latter half of the endurance. As for the durability, it could be used if the durability was about 500,000 sheets.

Thickening the plating is effective for contamination of the sleeve, but is designed based on the durable life required for the sleeve of the developing device and the material of the toner (such as easy contamination). It is not necessary to apply high-hardness plating to a toner cartridge or the like having a replaceable sleeve having a short life and a short life.

If the plating thickness is optimized as described above,
So far, AL sleeve blasted with spherical particles has been used, but SUS sleeve can also be used. That is, it is not necessary to use a relatively soft metal such as AL as the sleeve sleeve base material.
However, since SUS is more expensive than AL in the first place, AL is preferable in terms of cost and, of course, in terms of sleeve contamination and durability life due to contamination.

[Other Comparative Examples] Other comparative examples are shown below for reference.

The three types of toner used are as follows.

Toner (b): 80 parts by weight of styrene-butyl acrylate copolymer (Mw = 2.4 × 10 ⁵ , Mn = 7.2 × 10 ³ , Mw / Mn = 33.3) ・ Styrene-butadiene 20 parts by weight of copolymer (Mw = 2.2 × 10 ⁵ , Mn = 1.4 × 10 ⁴ , Mw / Mn = 15.7) ・ 90 parts by weight of magnetite ・ 2 parts by weight of nigrosine ・ Low molecular weight ethylene-propylene copolymer 4 parts by weight of polymer Using the above materials, a toner (b) was obtained in the same manner as in the toner (A).

In the molecular weight distribution of the THF-soluble component of the toner (b) by GPC, Mw was 1.7 × 10 ⁵ , Mn was
Was 9.0 × 10 ³ and Mw / Mn was 18.9.

The toner (b) uses nigrosine as the charge control agent for the toner (A).

Toner (c): 100 parts by weight of styrene-butyl acrylate copolymer (Mw = 2.4 × 10 ⁵ , Mn = 7.2 × 10 ³ , Mw / Mn = 33.3) Magnetite 90 parts by weight Part: triphenylmethane compound 2 parts by weight (Structure; specific example (1), 50% diameter = 1.35 μm, 10 μm or more: 0.8%, X-ray diffraction peak (2θ): 6, 12, 14, 18) .5 deg Other sharp peaks exist)-Low molecular weight ethylene-propylene copolymer 4 parts by weight Toner (c) was obtained in the same manner as toner (A) using the above materials.

In the molecular weight distribution of the THF-soluble component of the toner (c) by GPC, Mw was 1.6 × 10 ⁵ , Mn was
Was 7.1 × 10 ³ and Mw / Mn was 22.5.

The toner (c) does not contain a styrene-butadiene copolymer as a binder with respect to the toner (A).

Toner (d): 50 parts by weight of styrene-butyl acrylate copolymer (Mw = 2.4 × 10 ⁵ , Mn = 7.2 × 10 ³ , Mw / Mn = 33.3) ・ Styrene-butadiene 50 parts by weight of copolymer (Mw = 2.2 × 10 ⁵ , Mn = 1.4 × 10 ⁴ , Mw / Mn = 15.7) ・ 90 parts by weight of magnetite ・ 2 parts by weight of triphenylmethane compound (structure; specific) Example (1), 50% diameter = 0.81 μm, 10 μm or more: 0.0%, X-ray diffraction peak (2θ): 6, 12, 14, 18.5 deg Other sharp peaks exist) 4 parts by weight of low molecular weight ethylene-propylene copolymer Using the above materials, a toner (d) was obtained in the same manner as in the toner (A).

In the molecular weight distribution of the THF-soluble component of the toner (d) by GPC, Mw was 2.4 × 10 ⁵ , Mn was
Was 1.1 × 10 ⁴ and Mw / Mn was 21.8.

The toner (d) contains a larger amount of a styrene-butadiene copolymer as a binder than the toner (A).

These toners were used in the actual test example 1 of the embodiment 1.
As a result, the toner (b) has a low triboelectricity and low concentration due to a low charge control agent, and the toner (c) does not contain a styrene-butadiene copolymer. And the toner (d) has a problem of fixing failure due to too much styrene-butadiene copolymer, and the toner (d) does not reach the level of the toner (A). It was confirmed.

The differences between the present invention and the prior art will be clarified below based on the above results.

It has been well known that hard metal plating is applied to a surface layer of a soft metal such as aluminum as a method for increasing hardness in the first place.

For example, in the specification of Japanese Patent Application Laid-Open No. 57-86869 and Japanese Patent Application Laid-Open No. 58-132768, there is a description in which aluminum is plated. The latter has no detailed description about sandblasting. In the latter case, since the main effect is only in the hardening of the sleeve, no knowledge about sleeve contamination as in the present case can be obtained. Although the former has a description of sleeve contamination, the description mainly relates to SUS sleeves, the difference from blasting for aluminum sleeves is not recognized, and considering that blasting is due to irregular shaped particles. However, it is not considered to have a sufficient effect on sleeve contamination.

In Japanese Patent Application Laid-Open No. Sho 60-130770, a magnetic layer is provided on the surface by plating or the like.
It mentions its magnetic properties and does not disclose any knowledge about surface properties. Also, since it relates to two-component development, what corresponds to a sleeve for one-component development is essentially a carrier in two-component development and is not related to the present invention.

In Japanese Patent Application Laid-Open No. 61-219974, plating is performed on an alundum blast using alumina particles for blasting.

Recently, there has been proposed a method in which plating is performed after a spherical blast as disclosed in Japanese Patent Application Laid-Open No. 5-27581. However, there is no description about electrolytic plating or electroless plating with respect to plating. The knowledge of the toner property is only the point of the toner transport property, and there is no description about sleeve contamination.

Japanese Patent Application Laid-Open No. 3-41485 also discloses that aluminum plating is electroless plating, and there is no description of electroless plating with respect to plating, and that nickel plating in Examples is slightly magnetic. Therefore, the nickel plating here is considered to be electrolytic plating.

Japanese Patent Application Laid-Open No. Hei 3-233581 does not have a detailed description of blasting and plating.

In any of the above prior arts, there is no description of the relationship between electroless plating and the toner formulation of the present invention, and the styrene-butadiene copolymer is contained in the binder, and the trichloride is used as a charge control agent. The use of phenylmethane is patentable in this case.

The present invention is different from the prior art in the above points. "The styrene-butadiene copolymer is added to the binder in combination with the sleeve in which the electroless plating layer is formed and the sleeve contamination is reduced. Triphenylmethane was used as a charge control agent "in the patent.

In order to further bring out the effect, it is necessary to use a material having a low hardness for the base sleeve material,
It is preferable to perform a spherical blasting process, and to perform electroless plating with a relatively high hardness in order to keep the roughness of the sleeve close to the initial value over a long period of time.

In addition, as to all the above prior arts, the above prior arts have insufficient knowledge on the plating thickness and the surface properties after plating, and of course mention the relationship between the toner particle size used and the plating thickness. Nothing was done. For this reason, there is no technology in the prior art described above for suppressing sleeve contamination by increasing the plating thickness.

[0258]

As described above, a sleeve as a developer carrier made of a metal material disposed opposite to a latent image carrier for forming a surface latent image, and a developer held on the sleeve are provided. In a developing device which develops the latent image by adhering an agent to the surface of the latent image carrier, (1) electroless plating is performed on the sleeve, and more preferably, the sleeve is made of a relatively soft metal such as aluminum. After blasting with spherical particles, the electroless Ni-P and the electroless Ni-
B or electroless Cr plating or the like is used to fill the minute cracks in the recesses in the substantially uniform uneven surface after blasting, and to use a sleeve having a substantially mirror-finished inside of the recess, so that the toner adheres to the sleeve ( (2) The chargeability is slightly inferior to SUS as compared with SUS like a sleeve made of electroless Ni-P, Ni-B or Cr plating, and the change of tribo to the toner particle size is large. Even if a sleeve is used, the use of a charge control agent that would cause a blotch due to too high a charge in a normal magnetic blade coat system prevents blotches while increasing the chargeability. (3) Further, by using a styrene-butadiene copolymer as a toner binder, a change in toner tribo with respect to a change in toner particle diameter is reduced. Without sleeve contamination even with small particle size toner as result, no occurrence of blotches throughout the environment, there is an effect that can maintain good image quality, the concentration over time.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an image forming apparatus using a developing device of the present invention.

FIG. 2 is a configuration diagram of a developing device of the present invention.

FIG. 3 is a graph showing tribo in each environment after endurance using a toner of the present invention and a conventional toner using a developing device using a plating sleeve.

FIG. 4 is a graph showing tribo in various environments after the toner of the present invention and the conventional toner have been durable using a developing device using a conventional SUS sleeve.

FIG. 5 is a configuration diagram of another developing device of the present invention.

FIG. 6 is a schematic diagram of a cross section of a sleeve after blast processing with alundum particles.

FIG. 7 is a schematic view of a cross section of a sleeve after blasting with spherical particles.

FIG. 8 is a schematic view of a cross section of a resin coat sleeve.

FIG. 9 is an enlarged schematic view of a cross section of a concave portion of a sleeve after blasting with a spherical particle.

FIG. 10 is an enlarged schematic view of a cross section of a concave portion obtained by performing electroless plating on a sleeve after blasting with spherical particles.

FIG. 11 shows graphs of tribo in each environment after durability using a conventional toner with a developing device using a plating sleeve and a SUS sleeve.

[Explanation of symbols]

 Reference Signs List 5 developing sleeve 6 magnetic blade 6 'elastic blade 7 developing container 9 charging device 10 transfer device 11 cleaning device 12 photosensitive drum 13 developing device 14 magnet 15 power supply 51 sleeve base material 52 plating layer

Continued on the front page (72) Inventor Nobuaki Itakura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Naobuni Kobori 3-30-2 Shimomaruko, Ota-ku Tokyo (72) Inventor Takao Honda 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Hiroyuki Fujikawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Hirohide Tanikawa 3-30-2 Shimomaruko, Ota-ku, Tokyo F term in Canon Inc. (reference) 2H005 AA01 AA02 AA06 CA05 CA13 DA03 EA05 EA07 FA06 2H077 AD06 AD13 AD17 AD24 AD36 EA13 EA16 FA03 FA04 FA12 FA19 FA22 FA26 GA02 GA17

Claims (19)

[Claims] An image forming apparatus, comprising: a cylindrical sleeve arranged to face a latent image carrier for carrying a latent image, wherein a developer carried on the sleeve is provided with a developer facing the latent image carrier; Wherein the sleeve is formed by electroless plating on the surface of (i) the sleeve base material and (ii) the surface of the sleeve base material. Wherein the developer has a toner containing at least a styrene-butadiene copolymer as a binder resin and a triphenylmethane compound as a charge control agent. Developing device. 2. The surface of the sleeve base material is subjected to a roughening treatment with spherical particles before forming a plating layer by electroless plating, so that an uneven surface is uniformly formed. Item 2. The developing device according to Item 1. 3. The developing device according to claim 1, wherein the sleeve base material is formed of an aluminum alloy, a copper alloy, or a metal material having a Vickers hardness Hv of 50 to 150. 4. The electroless plating according to claim 1, wherein the electroless plating is electroless Ni-P plating, electroless Ni-B plating, electroless Cr or electroless Pd-P plating.
The developing device according to any one of the above. 5. The developing device according to claim 1, wherein the plating layer has a thickness of 1 to 50 μm. 6. The developing device according to claim 1, wherein said plating layer has a thickness of 5 to 25 μm. 7. When the plating layer is formed,
3. The uneven surface on the sleeve base material surface formed by the surface roughening treatment, wherein the concave surface retains the roundness caused by the collision of the spherical particles according to the shape of the spherical particles. 4. Developing device. 8. When the plating layer is formed,
3. The developing device according to claim 2, wherein the concave and convex surfaces on the surface of the sleeve base material formed by the surface roughening treatment are substantially mirror-finished. 9. The method according to claim 1, wherein the sleeve is non-magnetic, has a magnetic field generating means in the sleeve, and is a magnetic one-component developer having a magnetic toner as the developer. The developing device according to claim 1. 10. The developing device has a developer regulating unit for regulating an amount of a developer held on the sleeve, wherein the developer regulating unit is formed of a magnetic material and magnetically controls the developer. The developing device according to any one of claims 1 to 9, wherein a developer layer is formed on the sleeve while regulating. 11. The sleeve surface having the plating layer has a ten-point average roughness Rz of 2 to 15 μm and / or a center line average roughness Ra of 0.3 to 1.5 μm. 11. The developing device according to any one of 1 to 10. 12. The spherical particles are numbered # 100 to # 8.
The developing device according to claim 2, wherein the value is 00. 13. The toner has a weight average particle diameter of 4 to 10.
The developing device according to claim 1, wherein the thickness is μm. 14. The developing device according to claim 1, wherein said latent image carrier is an amorphous silicon drum and has a heater inside. 15. The developing device according to claim 1, wherein the electroless plating is Ni—P plating, and a P concentration is 5 to 15%. 16. The developing device according to claim 1, wherein the electroless plating is Pd-P plating, and the P concentration is 2 to 15%. 17. The developing device according to claim 1, wherein the electroless plating is Ni-B plating, and a B content is 2 to 8%. 18. The toner according to claim 1, wherein the toner contains the styrene-butadiene copolymer in an amount of 1 to 40% by weight based on the total weight of the binder resin. Developing device. 19. The triphenylmethane compound has a 50% diameter of 3 μm or less in an area-based particle size distribution measured by a centrifugal sedimentation method, and the content of particles having a particle diameter of more than 10 μm is 3% or less. 19. The developing device according to claim 1, wherein the developing device is a crystalline particle.