JPH07271096A - Toner for developing electrostatic charge image - Google Patents

Abstract

PURPOSE:To obtain a toner fixable at a low temp. without causing offsetting or winding on a heat roller at the time of heat contact fixation and less liable to filming on the surface of carrier powder and on the surface of a toner carrier during development. CONSTITUTION:This toner is a powdery toner consisting of a colorant and thermoplastic elastomer as a binder. The modulus of storage elasticity of the toner at 200 deg.C is 8.0X10<5>-1.0X10<4>dyn/cm<2>.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner for developing an electrostatic latent image formed in an electrophotographic method, an electrostatic recording method, an electrostatic printing method or the like.

[0002]

2. Description of the Related Art Generally, in electrophotography, electrostatic recording, etc., in order to develop an electrostatic latent image formed on an electrostatic latent image carrier made of a photoconductive photoreceptor or a dielectric, Develop with a two-component developer formed by mixing carrier powder and toner, or with a one-component developer that is thinned by a blade or the like on a toner supply roller such as a developing sleeve and is charged toner, A toner image is transferred onto a transfer material such as paper, if necessary, and then fixed by heating pressure, solvent vapor or the like to obtain a copy.

Although there are various toner fixing methods applied to these developing methods, the heat roller fixing method is widely used because of its high thermal efficiency and high-speed fixing. When high-speed fixing is performed by such a heat fixing method, the toner is required to have good low-temperature fixing property (or low fixing lower limit temperature). Further, if a low softening point resin is used as a binder for this purpose, a part of the toner image adheres to the surface of the heat roller during fixing, and this retransfers onto the copy paper, causing scumming on the copy paper. A so-called hot offset phenomenon or a so-called wrapping phenomenon (especially when the surface temperature of the heat roller is low) is likely to occur, in which the copy paper adheres to the surface of the heat roller and winds around. Therefore, as means for preventing these phenomena, Japanese Patent Laid-Open No. 51-1433.
No. 33, No. 57-148752, No. 58-9.
No. 7056, No. 60-247250 and the like propose adding a release agent such as solid silicone varnish, higher fatty acid, higher alcohol various waxes, etc. to the toner, but all of them have good low temperature fixability. While maintaining, sufficient offset resistance and wrapping resistance were not obtained. For example, polyolefin waxes such as low-molecular-weight polyethylene and low-molecular-weight polypropylene have good offset resistance, but their low-temperature fixability is not sufficient, and plant waxes such as carnauba wax and candelilla wax have offset resistance and low-temperature fixability. Is good, but the wrapping resistance is not sufficient, and solid silicone varnish, solid silicone oil, amide wax,
Higher fatty acids, higher alcohols, montanic acid waxes and the like have good low-temperature fixability, but insufficient offset resistance and wrapping resistance. Moreover, the conventional release materials have many so-called filming and spent in which the release agent is released from the toner and adheres to the photoconductor and the carrier during development, and it is difficult to form a high-quality image stably for a long period of time. there were.

[0004]

An object of the present invention is to enable low-temperature fixing without causing an offset phenomenon or a phenomenon of winding around a heat roller during fixing, and toner on a carrier powder surface or a toner carrier surface during development. An object of the present invention is to provide an electrostatic charge image developing toner with less filming.

[0005]

As a result of earnest studies for achieving the above object, as a result of using a thermoplastic elastomer as a binder component constituting a toner and measuring a dynamic viscoelasticity of the toner, 200 Storage modulus at ° C
It has been found that the problem can be solved by setting it to 8.0 × 10 ^{5 to} 1.0 × 10 ⁴ (dyne / cm ² ).

The thermoplastic elastomer has no cross-linking component in its molecular structure, but since it has a phase-separated structure, it has an apparent cross-linking structure in which molecules are self-aggregated. Therefore, although it is a thermoplastic polymer, it is rubber-like. It shows the property. Examples of the thermoplastic elastomer used in the present invention include styrene-based thermoplastic elastomer, olefin-based thermoplastic elastomer, polyester-based thermoplastic elastomer, polybutadiene-based thermoplastic elastomer,
Fluorine-based thermoplastic elastomers are suitable, and they can be used alone or in combination.

The thermoplastic elastomer used in the present invention may be the entire binder component used in the toner, but it is preferable that the binder component is contained in an amount of at least 30 parts by weight or more.

Materials usable in combination with the above-mentioned thermoplastic elastomer as a binder component include thermoplastic resins and low molecular weight polyolefins. As the plastic resin, styrene,
o-methylstyrene, m-methylstyrene, p-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert-butylstyrene, pn-hexylstyrene, p- n-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene,
Styrenes such as 3,4-dichlorostyrene; ethylenically unsaturated monoolefins such as ethylene, propylene, butylene, and isobutylene; vinyl halides such as vinyl chloride, vinylidene chloride, bromine vinyl, vinyl fluoride; Vinyl acetates such as vinyl acetate, vinyl propionate, vinyl acetate, methyl acrylate, ethyl acrylate, -n-butyl acrylate, methyl methacrylate,
Ethyl methacrylate, trifluoroethyl acrylate,
Hexafluoroisopropyl acrylate, tetrafluoropropyl acrylate, octafluoropentyl acrylate, α-methylene aliphatic monocarboxylic acid esters such as heptadecafluorodecyl acrylate, vinyl ethers such as vinyl methyl ether, vinyl methyl ketone,
Such as N-vinylpyrrole, N-vinylpyrrole, N-vinylcarbazole, N-vinylindole, N-vinylpyrrolidone, etc. have a weight average molecular weight of about 5
Examples include about 10,000 to 300,000 vinyl polymers.

Further, a polycondensation type resin can be used as the thermoplastic resin, and as a monomer for forming the polycondensation type resin, ethylene glycol, triethylene glycol, 1,2-propylene glycol and bisphenol are used. A, polyhydric alcohols such as hydrogenated bisphenol A, polyoxyethylenated bisphenol A, polyoxypropyleneated bisphenol A, polyamines such as ethylenediamine, tetramethylenediaminepiperazine, and maleic acid, fumaric acid, mesaconic acid, Examples thereof include citraconic acid, adipic acid, malonic acid, and their acid anhydrides or esters with lower alcohols.

As the thermoplastic resin, epoxy resin, polyol resin and the like well known in this field can be used together. The combined use of the thermoplastic resin has the effect of increasing the fixing power of the toner on the recording sheet.

Examples of low molecular weight polyolefins that can be used in combination include polyethylene, polypropylene, polybutylene and the like, and the weight average molecular weight is about 5,000 to about 50,000.
It is of a degree. By using this low molecular weight polyolefin in combination, the offset resistance can be further improved. However, if too much is used in combination, the fixing power is lowered and the spent property is deteriorated. From this point of view, the amount of the low molecular weight polyolefin used is 15% as a proportion of all the binder components.
It is good to set it as less than weight%, preferably about 1 to 8 weight%.

In the present invention, a thermoplastic elastomer is used as a binder for the above-mentioned toner, and a toner of
Storage elastic modulus at 00 ° C. was 8.0 × 10 ^{5 to} 1.0.
The initial purpose can be achieved by setting it to × 10 ⁴ (dyne / cm ² ). Storage modulus is a measure of the amount of energy absorbed by the toner with respect to external stress.
Rheometrics Dynamic Spectrometer (RD manufactured by trics)
S-II) is used, and as a sample, the toner is melted, pressure-molded, formed into a plate shape, and used for measurement. If the storage elastic modulus exceeds 8.0 × 10 ⁵ , the low temperature fixability is impaired,
On the other hand, if it is less than 1.0 × 10 ⁴ , there is a problem that the viscoelastic viscous component becomes dominant and hot offset easily occurs. In order to control the storage elastic modulus of the toner within the above range, it can be obtained by adjusting the combination of materials constituting the toner and the mixing ratio thereof.

In the toner of the present invention, it is possible to use additives such as a colorant and a charge control agent which are known to be conventionally used. Examples of these are carbon black and oil. Metal chelate dyes such as black, nigrosine dyes, metal-containing dyes, aniline dyes, chalco oil blue, chrome yellow, ultramarine blue,
Examples include methylene blue chloride, phthalocyanine blue, rose bengal, and the like.

In the toner of the present invention or on the surface thereof,
A fluidizing agent can be added or attached. As the fluidizing agent, conventionally well known inorganic fine particles such as silica, titanium oxide, alumina, calcium carbonate and silicon carbide, metal soap such as zinc stearate, and the like can be used. The inorganic fine particles are preferably subjected to a hydrophobic treatment because the chargeability of the toner is less likely to be affected by humidity.

The toner of the present invention can be obtained by pulverizing the above-mentioned materials by a method well known in the art, and the average particle diameter thereof is preferably 1 to 30 μm. The toner of the present invention is a one-component developer, iron, nickel,
Magnetic particles such as manganese and ferrite, resin particles in which magnetic fine powder is dispersed, glass particles, or carrier particles having an average particle size of about 10 to 200 μm in which a metal or resin coating layer is provided on the surface of these particles is mixed. Can be used as a two-component developer. As the one-component developer, there are a non-magnetic one-component system as it is and a magnetic one-component system in which a magnetic material is contained in the toner, and any one can be used.

[0016]

The present invention will be described in more detail with reference to the following examples, but it goes without saying that the present invention is not limited thereto. In the following examples, parts represent weight units and Mw represents average molecular weight.

Example 1 Polyester thermoplastic elastomer 95 parts Low molecular weight polypropylene (Mw = 8700) 5 parts Carbon black (coloring agent) 10 parts Lithic acid derivative zinc salt (charge control agent) 6 parts Melt kneading the above formulation, After cooling, it was coarsely pulverized using a hammer mill and then finely pulverized by an air jet type fine pulverizer. The obtained finely pulverized product was classified to obtain an average particle size of 7.
It was 5 μm. To 100 parts of the particles, 0.5 part of fine silica powder was added and mixed to obtain a toner. The storage elastic modulus at 200 ° C. obtained by measuring the dynamic viscoelasticity of this toner was 3.2 × 10 ⁴ (dyne / cm ² ). 5 parts of the obtained toner was mixed with 95 parts of a ferrite carrier to prepare a developer, and the developer was evaluated with Imagio 420 manufactured by Ricoh. A high-resolution image was obtained, and no offset to the fixing roller was observed. Even after copying 100,000 sheets, no photoreceptor filming, carrier spent, cleaning failure, or transfer failure was observed.

Example 2 Polyester thermoplastic elastomer 35 parts Styrene-butyl methacrylate copolymer (Mw = 130,000) 50 parts Low molecular weight polypropylene (Mw = 8700) 5 parts Carbon black (colorant) 10 parts Zinc salicylate derivative Salt (charge control agent) 6 parts The above formulation was melt-kneaded, cooled, coarsely pulverized using a hammer mill, and then finely pulverized by an air jet type fine pulverizer. The obtained finely pulverized product was classified to obtain an average particle size of 7.
It was 5 μm. To 100 parts of the particles, 0.5 part of fine silica powder was added and mixed to obtain a toner. The storage elastic modulus at 200 ° C. obtained by measuring the dynamic viscoelasticity of this toner was 2.5 × 10 ⁴ (dyne / cm ² ). 5 parts of the obtained toner was mixed with 95 parts of a ferrite carrier to prepare a developer, and the developer was evaluated with Imagio 420 manufactured by Ricoh. A high-resolution image was obtained, and no offset to the fixing roller was observed. Photoconductor filming, carrier spent, cleaning failure, and transfer failure were not seen even with 100,000 copies.

Example 3 Styrenic thermoplastic elastomer 70 parts Polyester resin 25 parts Low molecular weight polypropylene (Mw = 8700) 5 parts Carbon black (colorant) 10 parts Salicylic acid derivative zinc salt (charge control agent) 5 parts Melt the above formulation The mixture was kneaded, cooled, coarsely pulverized using a hammer mill, and then finely pulverized by an air jet type fine pulverizer. The finely pulverized product obtained was classified to obtain an average particle size of 8.
It was 4 μm. To 100 parts of the particles, 0.3 part of fine silica powder was added and mixed to obtain a toner. 20 of this toner
Storage elastic modulus at 0 ° C is 1.4 × 10 ⁴ (dyne / cm
² ) was. 5 parts of the obtained toner was mixed with 95 parts of a ferrite carrier to prepare a developer, and the developer was evaluated with Imagio 420 manufactured by Ricoh. A high-resolution image was obtained, and no offset to the fixing roller was observed. 100000
Photoconductor filming, carrier spent, cleaning failure, and transfer failure were not seen even on one copy.

Example 4 Styrene-butyl methacrylate copolymer (Mw = 130,000) 50 parts Fluorine-based thermoplastic elastomer 30 parts Polyester resin 15 parts Low molecular weight polypropylene (Mw = 8700) 5 parts Carbon black (colorant) 10 Parts Salicylic acid derivative zinc salt (charge control agent) 6 parts The above formulation was melt-kneaded, cooled, coarsely pulverized using a hammer mill, and then finely pulverized by an air jet type fine pulverizer. The finely pulverized product obtained was classified to obtain an average particle size of 8.
It was 8 μm. 0.4 part of silica fine powder was added to 100 parts of the particles and mixed to obtain a toner. 20 of this toner
Storage elastic modulus at 0 ° C is 2.6 × 10 ⁴ (dyne / cm
² ) was. 5 parts of the obtained toner was mixed with 95 parts of a ferrite carrier to prepare a developer, and the developer was evaluated with Imagio 420 manufactured by Ricoh. A high-resolution image was obtained, and no offset to the fixing roller was observed. 100000
Photoconductor filming, carrier spent, cleaning failure, and transfer failure were not seen even on one copy.

Example 5 Styrene-butyl methacrylate copolymer (Mw = 150,000) 50 parts Olefinic thermoplastic elastomer 30 parts Polyester resin 15 parts Low molecular weight polypropylene (Mw = 8700) 5 parts Carbon black (colorant) 10 parts 6 parts of salicylic acid derivative zinc salt (static control agent) The above formulation was melt-kneaded, cooled, coarsely pulverized using a hammer mill, and then finely pulverized by an air jet type fine pulverizer. The finely pulverized product obtained was classified to obtain an average particle size of 8.
It was 8 μm. 0.4 part of silica fine powder was added to 100 parts of the particles and mixed to obtain a toner. 20 of this toner
Storage elastic modulus at 0 ° C is 3.2 x 10 ⁴ (dyne / cm
² ) was. 5 parts of the toner obtained was mixed with 95 parts of a ferrite carrier to prepare a developer, and the developer was evaluated with Imagio 420 manufactured by Ricoh. A high-resolution image was obtained, and no offset to the fixing roller was observed. 100000
Photoconductor filming, carrier spent, cleaning failure, and transfer failure were not seen even on one copy.

Example 6 Styrene-butylmethacrylate copolymer (Mw = 160,000) 40 parts Polybutadiene thermoplastic elastomer 40 parts Polyester resin 15 parts Low molecular weight polypropylene (Mw = 8700) 5 parts Carbon black (colorant) 10 parts 6 parts of salicylic acid derivative zinc salt (static control agent) The above formulation was melt-kneaded, cooled, coarsely pulverized using a hammer mill, and then finely pulverized by an air jet type fine pulverizer. The finely pulverized product obtained was classified to obtain an average particle size of 8.
It was 8 μm. 0.4 part of silica fine powder was added to 100 parts of the particles and mixed to obtain a toner. 20 of this toner
Storage elastic modulus at 0 ° C is 2.1 x 10 ⁴ (dyne / cm
² ) was. 5 parts of the toner obtained was mixed with 95 parts of a ferrite carrier to prepare a developer, and the developer was evaluated with Imagio 420 manufactured by Ricoh. A high-resolution image was obtained, and no offset to the fixing roller was observed. 100000
Photoconductor filming, carrier spent, cleaning failure, and transfer failure were not seen even on one copy.

Comparative Example 1 A toner was prepared in the same manner as in Example 2 except that the thermoplastic polyester elastomer was not used and the styrene-butyl methacrylate copolymer was changed to 95 parts. The storage elastic modulus of this toner at 200 ° C. is 2.5 × 10 ^1.
(Dyne / cm ² ). Further, when the evaluation was performed in the same manner as in Example 2, hot offset occurred in the fixing roller.

Comparative Example 2 A toner was prepared in the same manner as in Example 3 except that a urethane type thermoplastic elastomer was used instead of the styrene type thermoplastic elastomer in Example 3. 200 ℃ of this toner
The storage elastic modulus was 4.5 × 10 ¹ (dyne / cm ² ). Next, when the same evaluation as in Example 3 was performed, hot offset occurred in the fixing roller.

[0025]

The toner of the present invention enables low-temperature fixing without causing an offset phenomenon or a phenomenon of winding around a heat roller at the time of heat fixing, and is a toner on the surface of a carrier powder or the surface of a toner carrier during development. It has an effect that there is little filming.

Claims (4)

[Claims] 1. A powdery electrostatic image developing toner comprising a colorant and a binder, which contains a thermoplastic elastomer as the binder and has a storage elastic modulus at 200 ° C. of 8 0.0 × 10 ^{5 to} 1.0 × 10
⁴ (dyne / cm ² ), a toner for developing an electrostatic charge image. 2. The binder is a thermoplastic elastomer,
The electrostatic image developing toner according to claim 1, comprising a thermoplastic resin and a low molecular weight polyolefin. 3. The electrostatic image developing toner according to claim 1, wherein the proportion of the thermoplastic elastomer in the binder is 30% by weight or more. 4. The thermoplastic elastomer is at least one selected from the group consisting of a styrene-based thermoplastic elastomer, an olefin-based thermoplastic elastomer, a polyester-based thermoplastic elastomer, a polybutadiene-based thermoplastic elastomer, and a fluorine-based thermoplastic elastomer. The toner for developing an electrostatic charge image according to claim 1, comprising: