JPS61273555A - Electrostatic charge image developing toner - Google Patents

Abstract

PURPOSE:To obtain a light-transmitting toner adapted to projection of a sharp color image by using a toner composed of a polyester type and/or an epoxy resin, a colorant, and a Fischer-Tropsch wax. CONSTITUTION:The toner is composed of a 60-90wt% polyester type resin, a 40-10wt% epoxy resin, a colorant, and a Fischer-Tropsch wax in an amt. of 2-40wt% of the toner resin component. This wax can keep the light transmittance of the binder resin good, thus permitting the obtained toner to be high enough in light transmittance to be used for projecting a sharp color image with an overhead projector and like.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a toner for developing electrostatic latent images in electrophotography, electrostatic recording, etc. This invention relates to toner suitable for forming images.

<Prior Art> Many methods have been known for electrophotography, but in general, an electrostatic image is formed on a photoreceptor using a photoconductive substance by various means, and then the latent image is The toner image is developed mainly by a magnetic brush development method, the toner image is transferred to a transfer material such as paper, and the toner image is then fixed by heating or pressure to obtain a copy.

The use of image forming techniques using electrophotography and the like is rapidly expanding as modern information becomes more complex and diverse. Accordingly, the image forming technology is required to be compatible with various uses such as digitization and colorization.

Among these required technologies, a copy of characters and images formed using black or chromatic toner on a transparent film is projected onto a projection surface such as a white board using an overhead projector (hereinafter referred to as OHP). An attempt is being made to do so.

However, when making OHP copies using a PPC electronic copying machine using toner in the prior art, even if the toner image is a chromatic color other than black, the projected image obtained is a clear color image. It does not become a chromatic color, but becomes a black-gray color. This is because the light from the toner image area cannot reach the projection surface due to the poor light transmittance of the toner, and the image area appears as a shadow.

<Problems to be Solved by the Invention> The present invention provides a light-transmitting toner suitable for projecting clear color images using OHP or the like.

Means for Solving the Problems As a result of studying the material composition of toner to maintain light transmittance in color toner, the present inventors applied polyester resin and/or epoxy resin as the binder resin. Furthermore, we have found that a significant effect can be obtained by incorporating Fischer-Tropsch wax as an additive to prevent the offset phenomenon during hot roll fixing.

The polyester-based resin referred to in the present invention refers to a rosin-based linear resin in which rosin groups are regularly arranged in the side chain of the molecule, which can be obtained by, for example, heating a rosin glycidyl ester and a dicarboxylic acid derivative or its anhydride. All polyester resins that can be normally used for toners can be applied to the present invention, such as polyester resins having a bisphenol structure obtained by condensation polymerization of a polyester resin or a polyol such as a diol component and a polyhydric carboxylic acid. . Among these polyester resins, rosin-based linear polyester resins such as Moto (trade name Lunaveil 1400 (manufactured by Arayo Kagaku Co., Ltd.) are excellent in light transmittance and charging stability, and are preferably used in the present invention. Vine.

In addition, the epoxy resin referred to in the present invention is not only a general-purpose Ebisu type obtained by polycondensing epichlorohydrin and bisphenol A, but also a variety of epoxy resins, such as rubber-modified, fatty acid-modified, and brominated-modified resins, depending on the characteristics required for toner. Modified epoxy resins of 1 and 2 are provided in the present invention. Among them, a high-purity epoxy resin having a relatively high melt viscosity characteristic and a high content of terminal epoxy groups (for example, Evoto YD904 manufactured by Tobu Kasei Co., Ltd.) is preferably used in the present invention.

In the present invention, the above-mentioned polyester resin and epoxy resin can be used alone or in combination as a binder resin, but preferably 40 to 10 parts by weight of the epoxy resin is used for 60 to 90 parts by weight of the polyester resin. A resin system mixed at a suitable mixing ratio is preferable.

The above-mentioned polyester and/or epoxy resin used in the present invention has the advantage of having better light transmittance than other styrene resins, etc., and because the polyester resin itself has a negatively charged polarity, it is light-transmissive. The amount of a charge control agent made of a colored metal-containing compound that inhibits permeability can be significantly reduced (or even eliminated), and it also has effects such as vinyl chloride resistance.

The colorant used in the toner according to the present invention is OHP.
A dye or pigment is used that sharpens the color image projected by the dye. For example, anthraquinone, calco oil blue, chrome yellow, ultramarine blue,
DuPont oil red, quinoline yellow, methylene blychloride, phthalocyanine blue, malachite green offsalate, rose bengal and mixtures thereof are used, which can be developed to produce a visible image or OHP.
It is necessary to contain an appropriate amount in the toner so that a projected image can be formed clearly.

Fischer used in the toner according to the present invention.
Tropsch wax is a wax that is produced as a by-product when synthetic petroleum is produced from coal by a hydrocarbon synthesis method, and is commercially available, for example, under the trade name "Sasol Wax" manufactured by Sasol Corporation. The chemical structure is a saturated long straight chain hydrocarbon with a small number of methyl branches, and the isoparaffin content is approximately 10%. It has a longer linear structure compared to normal paraffin wax, and is a linear molecule with fewer side chains than microwax. The crystal structure is a plate-like crystal.General Chemistry 2〇. H2n+2, average molecular weight approximately 6
80, carbon number distribution from C33 to Cl2O is applied to the toner of the present invention.

Furthermore, the Fischer-Tropsch wax referred to in the present invention also includes oxidized type waxes (trade names: Sasol Wax A1, A2, etc.) having an acid value of 3 to 3 ON-KOII/g. Fischer included in the toner;
The amount of Tropsch wax varies depending on the resin components of the toner, the types of colorants and toner additives, and their usage amounts, but is generally 2 to 40 parts by weight, preferably 5 to 20 parts by weight, per 100 parts by weight of toner resin components. Parts by weight.

The effect of Fischer-Tropsch wax in the present invention is that the light transmittance of the binder resin can be maintained in a good state. That is, in the conventional toner for hot roll fixing, a release agent such as a low molecular weight polyolefin is generally added to impart release properties to the molten toner in order to prevent the offset phenomenon. However, such known mold release agents have poor compatibility with the binder resin, and therefore have a poor dispersion state in the binder resin. Light transmission is significantly inhibited by light scattering and diffused reflection.

The Fischer-Tropsch wax referred to in the present invention has an anti-offset effect that is better than that of conventional mold release agents, and also has good compatibility with the binder resin, so the dispersion state in the binder resin is Therefore, a toner with extremely good light transmittance can be obtained.

In other words, Fischer-Tropsch wax does not need to be blended with conventional mold release agents such as low molecular weight polyolefins, which are present in the binder resin and cause problems in light transmittance.

The toner according to the present invention may also contain various charge control agents such as nigrosine and metal-containing dyes, fluidizing agents such as hydrophobic silica,
Cleaning agents such as fatty acid metal salts, fillers such as calcium carbonate, and other additives may be blended as appropriate.

To make the toner of the present invention using the above materials,
After premixing each component in a predetermined ratio, they are melt-kneaded using an extruder, hot roll, etc., then coarsely pulverized using a hammer mill, etc., finely pulverized using a jet mill, and classified using a classifier.
The average particle size may be adjusted to about 20 μm.

The toner of the present invention can also be used for color copying on ordinary transfer paper other than OHP, and can also be used as a toner for ordinary monochrome copying using carbon black as a colorant.

Furthermore, the present invention is not limited to negatively chargeable two-component developers, but can be made into positively chargeable two-component developers by blending an appropriate positively chargeable charge control agent, and by selecting an appropriate magnetic material. By blending, it can also be implemented as a one-component developer.

<Example> The present invention will be explained in detail below with reference to Examples.

Example 1 The above components were premixed, then melted and kneaded using an extruder, cooled, pulverized using a jet mill, and classified to obtain a red negatively charged toner having a particle size of 15 μm.

A two-component developer was prepared by mixing 6 parts by weight of this toner with 100 parts by weight of iron oxide powder carrier. The charge amount of this toner by the blow-off method was -16 μc/g.

This developer was applied to a PPC electronic copying machine equipped with a Se photoreceptor and a Teflon/silicone oil-free heat fixing mechanism, and a color toner image was copied onto the OHP transparent film as a transfer material.
880 (manufactured by Ricoh), the colors of the red toner image on the film were directly obtained as clear colors of the projected image.

On the other hand, when 5,000 sheets of continuous copying were made using high-quality paper as the transfer material, stable and clear color images could always be obtained without any offset phenomenon caused by the hot roll.

Example 2 Anthraquinone blue dye (Sandoz 5-RLS) was used instead of the dye in the toner composition in Example 1.

A blue negatively chargeable toner was obtained using the same manufacturing method.

A developer obtained by mixing 6 parts by weight of this toner and 100 parts by weight of iron oxide powder carrier was applied to a Se photoconductor and a Teflon/
PPC with silicone and oil-free heating fixing mechanism
When applied to a copying machine, the same results as in Example 1 could be obtained.

Example 3 Sasol Wax H in the toner composition in Example 1
A red negatively charged toner was obtained in the same manner as above, using an oxidized type Fischer-Tropsch wax (Sasol wax Al) having an acid value of 25 to 30+agKOH/g instead of Example 1.

A developer obtained by mixing 6 parts by weight of this toner and 100 parts by weight of iron oxide powder carrier was applied to a Se photoconductor and a Teflon/
PPC with silicone and oil-free heating fixing mechanism
When applied to a copying machine, the same results as in Example 1 were obtained.

Comparative Example 1 The above composition was subjected to the same manufacturing method as in Example 1 to obtain a red negatively chargeable toner.

A two-component developer was prepared by mixing 6 parts by weight of this toner with 100 parts by weight of iron oxide powder carrier. This developer is
When applied to a PPC copying machine having an e-photoreceptor and evaluated in the same manner as in Example 1, the OHP projected image turned out to be a black-gray image, confirming that the light transmittance of the toner was insufficient.

Comparative Example 2 The above composition was subjected to the same manufacturing method as in Example 1 to obtain a red negatively chargeable toner.

A two-component developer was prepared by mixing 6 parts by weight of this toner with 100 parts by weight of iron oxide powder carrier. This developer is
When applied to a PPC copying machine having an e-photoreceptor and evaluated in the same manner as in Example 1, the OHP projected image turned out to be a black-gray image, confirming that the light transmittance of the toner was insufficient.

<Effects of the Invention> Since the present invention has the above-described structure, it is possible to obtain a toner with excellent light transmittance, and it is possible to obtain a clear projected image for OHP projection, which was impossible with the conventional technology. . Furthermore, since the toner of the present invention has excellent properties for image formation on ordinary paper, it has become possible to develop a wide range of uses for the toner.

Claims (1)

[Claims] A toner for developing electrostatic images, characterized by containing a polyester resin and/or an epoxy resin, a colorant, and Fischer-Tropsch wax.