JPH05257319A - Electrostatic charge image developing toner - Google Patents

Abstract

PURPOSE:To improve the working environment of the production of a toner, and to obtain a toner showing stable fogging and having good splashing state of the toner and little change in the density of copied picture images in continuous copying without deteriorating the dispersibility of the coloring agent in the toner under any use environment by including a resin and a granulated coloring agent in the toner. CONSTITUTION:Any well-known resin suitable for an electrostatic charge image developing toner may be used as the resin component. Any powder coloring agent may be used for the source material of the granulated coloring agent. The powder coloring agent is compacted under such load properly determined to obtain 1.2-2.0 bulk density ratio and more preferably 1.2-1.8 bulk density ratio before and after granulating. If the bulk density ratio is <1.2, splashing of the coloring agent increases during handling the coloring agent and the bulk volume of the source material increases. This makes shearing difficult during kneading, and dispersibility of the coloring agent in the toner becomes bad to deteriorate the toner performance. If the bulk density ratio is >2.0, aggregation of the coloring agent increases and enough dispersibility is not obtd. during kneading and deteriorates the toner performance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic charge image developing toner used in electrophotography, electrostatic recording and the like.

[0002]

2. Description of the Related Art A developer used in an electrophotographic method such as an electronic copying machine is once attached to an image bearing member such as a photoconductor on which an electrostatic charge image is formed in the developing process, and then, A well-known method is generally used, in which a method of transferring from a photoconductor to a transfer paper in a transfer step and then fixing the copy paper surface in a fixing step is well known. At that time, as a developer for developing the electrostatic charge image formed on the latent image holding surface, a two-component developer comprising a carrier and a toner and a one-component developer (magnetic toner or Non-magnetic toner) is known. The toner contained in these developers is usually fine colored particles containing a resin, a colorant and the like as main components. Further, the toner includes positively charged toner and negatively charged toner. Conventionally known charge control agents and known coating agents for imparting desired chargeability to carriers have been known as agents for imparting positive or negative chargeability to toners. As a method for producing toner particles, a method is known in which an appropriate amount of each component such as a binder resin and a colorant is blended and mixed, subsequently kneaded with a kneader or the like, cooled, and then pulverized and classified.

[0003]

Generally, powdery dyes and pigments are generally used as colorants, but the colorants often fly during handling of raw materials in the toner manufacturing process.
Environmental pollution around the worker's body and the workplace has been a problem. In order to deal with such a problem, a method of performing preliminary dispersion treatment, so-called master batch treatment, by pre-kneading a resin and a colorant in advance has been proposed. In addition, the manufacturing process was complicated (the production efficiency was reduced), etc.

That is, an object of the present invention is to provide a toner using a colorant, which can reduce the pollution of the working environment at the time of toner production and can facilitate the handling work such as storage and transportation. Especially. Another object is to provide a toner in which a resin and other internal additives and a colorant are dispersed at a high and stable level, and an object of the present invention is to provide a stable image during continuous copying and printing. Concentration is obtained,
An object of the present invention is to provide a toner with less fog and less likely to cause a toner scattering phenomenon.

[0005]

The object of the present invention, however, is that the inventors of the present invention diligently studied various results, and as a result, the use of a granulated colorant, and the volume density ratio at the time of granulation was appropriately adjusted. It was found to be achieved by using a granulated colorant adjusted to That is, the present invention provides a toner for developing an electrostatic image containing at least a co-resin and a granulated colorant, and further, the bulk density ratio of the colorant before and after granulation is 1.2 to 2. The present invention provides a toner for developing an electrostatic charge image, which is 0.

Further, the present invention provides a toner for developing an electrostatic charge image, characterized in that the above-mentioned granulated colorant is prepared by a compression granulation method. The present invention will be described in detail below. In the present invention, various known resin components suitable for toners for developing electrostatic images can be used as the resin component.

For example, polystyrene, chloropolystyrene, poly-α-methylstyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-acetic acid. Vinyl copolymer, styrene-maleic acid copolymer, styrene-acrylic acid ester copolymer (styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene -Octyl acrylate copolymer and styrene-phenyl acrylate copolymer), styrene-methacrylic acid ester copolymer (styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-methacrylic acid) Butyl copolymer and styrene-meta Styrene-based resins such as phenyl phenyl copolymer), styrene-α-methyl methyl acrylate copolymer and styrene-acrylonitrile-acrylic acid ester copolymer (homopolymers or copolymers containing styrene or styrene substitute) ), Vinyl chloride resin, rosin-modified maleic acid resin, phenol resin, epoxy resin,
Polyester resin, low molecular weight polyethylene, low molecular weight polypropylene, ionomer resin, polyurethane resin,
There are silicone resins, ketone resins, ethylene-ethyl acrylate copolymers, xylene resins, polyvinyl butyral resins and the like, and particularly preferred resins for use in the present invention are styrene resins, saturated or unsaturated polyester resins and epoxy resins. Can be mentioned. Further, the above resins are not limited to being used alone, but may be used in combination of two or more kinds.

Further, the above resin is composed of a low molecular weight component and a high molecular weight component described in, for example, JP-B-55-6895 and JP-B-63-32180, in consideration of fixing performance and developer durability. Resin having at least two molecular weight peaks, or JP-B-51-2335
4, a partially crosslinked resin described in JP-A-50-44836 may be used. The glass transition temperature of the resin preferably has a transition start temperature (inflection point) of 50 ° C. or higher when measured with a differential thermal analyzer or a differential scanning calorimeter. When the glass transition temperature is lower than 50 ° C., when the toner is left at a high temperature of 40 ° C. or higher for a long time, the toner agglomerates or the toner sticks, which is a problem in use.

The raw material of the granulated colorant used in the present invention is not particularly limited as long as it is an ordinary powdery colorant. A method of granulating a powdery colorant is described in, for example, JP-A-2-14285.
8. A compression granulation method using a compression granulation apparatus such as a roll compression molding machine described in JP-A-3-193129 is preferably used for obtaining a desired bulk density ratio. The load for compressing the powdery colorant has a bulk density ratio of 1.2 to 2.0 before and after granulation in consideration of the bulk density and particle size of the raw material.
Preferably, it is appropriately selected so as to be 1.2 to 1.8.

When the bulk density ratio is less than 1.2, the flying of the coloring agent is large during the handling work, the bulk of the raw material is increased, the shear during kneading is less likely to occur, the dispersibility in the toner is deteriorated, and the toner performance is improved. Lead to deterioration. If the bulk density ratio is greater than 2.0, the colorant is easy to handle, but the cohesive force of the colorant increases too much, and sufficient dispersibility cannot be obtained during kneading, resulting in poor toner performance. Further, the stability of image density, the stability of fog, and the state of toner scattering during continuous copying and printing of toner are considerably improved by using the granulating colorant. Any appropriate pigment or dye is used as the colorant.

For example, titanium oxide, zinc white, alumina white, calcium carbonate, navy blue, carbon black, lamp black, iron black, ultramarine blue, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa yellow G, rhodamine dyes and pigments, chrome yellow. Any known dyes and pigments such as quinacridone, benzidine yellow, rose bengal, triallylmethane dye, anthraquinone dye, monoazo and disazo dyes may be used alone or in combination. These colorants are preferably 0.5 to 100 parts by weight of the binder resin.
It is used in an amount of 20 parts by weight, more preferably 2 to 10 parts by weight.

The bulk density of the colorant was measured according to the apparent specific gravity measuring method described in JIS K6221. For the purpose of adjusting the chargeability of the toner, in the case of a positively chargeable toner, a known charge control agent such as a nigrosine dye, a quaternary ammonium salt, a triaminotriphenylmethane compound, an imidazole compound, or a negatively chargeable toner is used. In such a case, a known charge control agent such as a metal-containing azo dye, a salicylic acid metal compound and an alkylsalicylic acid metal compound may be added in an appropriate amount. The addition amount is preferably 0.05 to 10 parts by weight with respect to 100 parts of the resin.

In addition to these, it is possible to add various plasticizers, auxiliary agents such as release agents, etc. to the toner for the purpose of adjusting thermal characteristics, physical characteristics and the like. The addition amount is preferably 0.1 to 10 parts by weight with respect to 100 parts of the resin. Further, by adding fine powder of titania, alumina, silica or the like to the toner particles and coating the surface of the toner particles with these powders, the fluidity and aggregation resistance of the toner can be improved. The addition amount is preferably 0.05 to 5 parts by weight with respect to 100 parts by weight of the toner particles.

When the toner of the present invention is used in a two-component developer, it may be used by mixing it with a magnetic carrier, and the content ratio of carrier to toner in the developer is 100 :.
1 to 10 parts by weight is preferable. As a magnetic carrier,
Conventionally known materials such as iron powder, ferrite powder, magnetite powder, and magnetic resin carrier having a particle size of about 30 to 200 μm can be used. Further, those whose surface is coated with a known silicone resin, acrylic resin, fluorine resin or the like, or a mixture of these resins can also be suitably used.

The toner of the present invention can also be used as a magnetic one-component toner containing a magnetic substance such as magnetite or a non-magnetic one-component toner containing no magnetic substance, which is a one-component developer which does not use a carrier. You can

[0016]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples without departing from the scope of the invention. In the following examples, simply "parts" means "parts by weight".

<Example 1>

[Table 1] Styrene / n-butyl acrylate = copolymer resin having a monomer weight ratio of 82/18 100 parts (flow softening point 130 ° C., glass transition point 62 ° C.) Colorant carbon black MA7 F 5 parts (Mitsubishi Kasei) Co., Ltd., granulation type, bulk density ratio = 1.36) ・ Charge control agent Bontron P51 2 parts (Orient Chemical Co., Ltd. quaternary ammonium salt) ・ Low molecular weight polypropylene viscol 550P 2 parts (Sanyo Chemical Co., Ltd. ))

And kneading with a continuous twin-screw extruder,
It was crushed and classified to obtain a black toner having an average particle size of 10 μm. To 100 parts of this black toner, 0.2 part of silica powder (R972 manufactured by Nippon Aerosil Co., Ltd.) was externally added using a Henschel mixer to obtain a toner A. 100 parts of a ferrite powder carrier having an average particle size of 100 μm, which is surface-coated with 4 parts of the obtained toner A and a resin containing methyl silicone.
The parts were mixed and stirred to prepare a developer.

Next, this developer was used at 40 ° C./85 to 90% RH by using a copying machine having an organic photoconductor as a photoreceptor.
Of 100,000 sheets under high temperature / high humidity conditions. The replenishment toner used for the live-action test is
Toner A having the same composition as the toner used in the developer
Is. As a result of the actual copying test, even after the actual copying after 100,000 copies, the uniformity and the density of the black portion of the copy are high and stable, and there is almost no increase in the fog that is the stain on the white background portion of the copy, and the toner is scattered inside the machine. The toner and the developer were substantially free from contamination and had excellent durability even in a severe environment of high temperature and high humidity. When the degree of dispersion of carbon black in the black toner A was observed with an optical microscope, good dispersion was confirmed.

<Example 2>

[Table 2] Styrene / n-butyl acrylate = 100 parts copolymer resin with a monomer weight ratio of 82/18 ・ Colorant copper phthalocyanine blue granulated product (bulk density ratio = 1.50) ・ Charge control agent Bontron P512 Part (Quaternary ammonium salt manufactured by Orient Chemical Co., Ltd.)-Low molecular weight polypropylene VISCOL 550P (manufactured by Sanyo Kasei Co., Ltd.) A toner and a developer were prepared in the same manner as in Example 1 except that 2 parts were prepared. Table 1 shows the results of the actual shooting test of 000 sheets.

Comparative Example 1 Powdered carbon black (MA7P, bulk density 0.22 g) before granulation of the colorant of Example 1
/ M ³ ), except that the toner and the developer were prepared in the same manner as in Example 1 and the actual copying test of 100,000 sheets was carried out.

<Comparative Example 2> Powdered copper phthalocyanine bleb before granulation of the coloring agent of Example 2 (bulk density 0.20 g /
except that the m ³⁾ is manufactured in the same manner as the toner and developer of Example 2, Table 1 shows the result of the 100,000 live action test.

[0023]

[Table 3]

(Note) The colorants of Examples 1 and 2 were used after being granulated by a roll compression molding machine.

[0025]

By using the toner for developing an electrostatic charge image of the present invention, the working environment during the toner production is remarkably improved, and the dispersibility of the colorant in the toner is not deteriorated. In addition, regardless of the conditions of the use environment, the change in the copy image density during continuous copying is small, the fog is stable, and the toner scattering state is excellent. Is provided.

Claims (3)

[Claims] 1. A toner for developing an electrostatic image, comprising at least a resin and a granulated colorant. 2. The electrostatic image developing toner according to claim 1, wherein the granulated colorant has a bulk density ratio of 1.2 to 2.0 before and after granulation. 3. The toner for developing an electrostatic charge image according to claim 1, wherein the granulated colorant is a colorant prepared by a compression granulation method.