JPS6357788B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a negatively charged color magenta toner used in color electrophotography and the like.

U.S. Patent No. 2297691 as a conventional electrophotographic method,
Various methods are described in JP-A-42-23910 and JP-A-43-24748, but in general, a photoconductive substance is used to create an electrical latent on a photoreceptor by various means. An image is formed, and then the latent image is developed with toner, and if necessary, the powder image is transferred to paper or the like and then fixed by heating, pressure, solvent vapor, or the like. In addition, in order to obtain a multicolor image, the original is exposed using a color separation filter, and the above process is repeated multiple times using color toners such as yellow, magenta, and cyan, and the toner images are superimposed to form a color image. It is something.

These color toners are required to have various characteristics, such as excellent loadability similar to black toner for black and white copying, low environmental dependence, and low deterioration with repeated and continuous use. On the other hand, the characteristics unique to color toners include good spectral reflection characteristics, good mixability, and high transparency, which are essential properties. There must be.

However, materials such as colorants that can be used to improve hue, transparency, etc. are limited, and it is not possible to fully satisfy chargeability and durability during continuous use.Therefore, there is a demand for improvements in color toners. The current situation is that this continues.

For example, JP-A-54-136836 proposes a positively charged toner containing CI Solvent Red 49. Although the toner is satisfactory in terms of color, there are still points to be improved in light fastness and environmental stability. Moreover, a negatively charged toner containing CI Solvent Red 52 is proposed in Japanese Patent Application Laid-Open No. 53-68234. Although this toner is excellent in negative triboelectric properties, the vividness of magenta color is insufficient.

The present invention was made in view of the above-mentioned current situation, and its main purpose is to provide a product that has good spectral reflection characteristics, color mixing properties, and transparency, and is also excellent in terms of chargeability, durability, environmental dependence, etc. An object of the present invention is to provide a negatively charged magenta toner having the following characteristics. Specifically, the present invention contains 0.1 to 5 wt% of a compound classified as CI Solvent Red 49 and CI Solvent Red 52 in the toner binder resin.
Contains 0.1 to 10 wt% of a compound classified as and 2 to 10 wt% of a chromium complex of alkyl salicylic acid,
In addition, the amount of the compound classified as CI Solvent Red 49 shall be the same as or less than the sum of the amount of the compound classified as CI Solvent Red 52 and the amount of the chromium complex of alkyl salicylic acid used. The present invention relates to a negatively charged magenta toner.

The constituent components of the toner of the present invention will be explained below.

Particularly important components of the toner of the present invention are compounds classified as CI Solvent Red 49 and CI Solvent Red 52, and chromium complexes of alkylsalicylic acids.

Examples of compounds classified as CI Solvent Red 49 are Aizen Rhodamine B Base,
There are rhodamine B bases such as Rhodamine Base FB, which have an extremely good hue as magenta and have high tinting power, giving a clear hue with a small amount of addition. The amount used is approximately 0.1 to 5 wt% based on the toner binder resin, and is within this range. If it is less than 0.11wt%, the coloring power is insufficient, and 5wt%
% or more is undesirable as it has a serious effect on the negative chargeability.

Furthermore, the usage amount of this compound is the usage amount of a compound classified as CI Solvent Red 52, which will be described later.
The amount needs to be equal to or less than the sum of the amount of alkyl salicylic acid and the chromium complex used.

If a large amount of a compound classified as CI Solvent Red 49 is used, the negative chargeability will be weak and so-called fog will occur, which is not preferable.

Compounds classified as CI Solvent Red 52 include Helio Oil Red R and Macrolex Red 5B, which, when used in combination with a chromium complex of alkylsalicylic acid, have better toner properties than when used alone, such as It can provide negative chargeability, durability in continuous use, environmental dependence (for example, moisture resistance, light resistance), etc. The amount used depends on the chargeability of the binder resin, CI Solvent Red 49
It can be determined by taking into consideration other conditions such as the amount of addition, the manufacturing method including the dispersion method, and the chargeability of other additives. Approximately for toner binder resin
0.1 to 10 wt% is appropriate and should be within this range.
If it is less than 0.1 wt%, the charge control effect will be small, and if it exceeds 10 wt%, the desired hue may be impaired.

Alternatively, a chromium complex of alkyl salicylic acid can be prepared by dissolving alkyl salicylic acid in a solvent such as methanol, ethanol, ether, or ketone, and adding an aqueous solution of chromic sulfate to the solution so that the molar ratio of salicylic acid and chromium is 2:1. and then add an alkaline aqueous solution to adjust the PH.
The precipitate that forms after several hours of relaxation can be filtered.

The alkyl group is preferably a tertiary butyl group or a tertiary aluminum group.

This chromium complex of alkyl salicylic acid exhibits a light color to the extent that it can be considered substantially colorless, and when used in combination with CI Solvent Red 52, provides suitable toner properties. The amount used depends on other conditions such as the chargeability of the binder resin, the amount of CI Solvent Red 49 added, the toner manufacturing method including the dispersion method of the amount of CI Solvent Red 52, and the chargeability of other additives. It can be determined to give preferable hue and toner characteristics by taking into account the following. It is used in an amount of approximately 2 to 10 wt% based on the binder resin.
If it is less than 2wt%, the charge control effect will be small, and if it exceeds 10wt%, the desired hue may be impaired.

All known binder resins can be used for the toner of the present invention, including monopolymers of styrene and its substituted products such as polystyrene, polyP-chlorostyrene, and polyvinyltoluene, and styrene-P-chlorostyrene. Styrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-acrylic acid Butyl copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α chlormethacrylate acid methyl copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene Copolymers, styrenic copolymers such as styrene-acrylonitrile-indene copolymers, styrene-maleic acid copolymers, styrene-maleic acid ester copolymers, polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, poly Vinyl acetate, polyethylene, polypropylene, polyester, polyurethane, polyamide, epoxy resin, polyvinyl butyral, polyamide, polyacrylic resin, rosin, modified rosin, terpene resin, phenolic resin, aliphatic or alicyclic hydrocarbon resin, aromatic resin Petroleum resin, chlorinated paraffin, paraffin wax, etc. can be used alone or in combination. Further, as the carrier used for the developer, conventionally known carriers can be used. For example, magnetic materials such as iron, cobalt, and nickel, alloys and mixtures thereof, or coatings on the surfaces thereof are used.

Furthermore, regarding the developer in which the toner of the present invention is used, preferably 0.01% to 5% by weight of a fluidity improver such as colloidal silica is added to the toner.
It may be added in an amount of about 0.1% to 2% by weight.

The present invention will be explained in more detail with reference to Examples below.

Example 1 100 parts by weight of styrene-maleic acid copolymer resin,
Rhodamine Base FB0.5 parts by weight, Macrolex Red
0.7 parts by weight of 5B and 4 parts by weight of the chromium complex of ditertiary butylsalicylic acid were mixed and pulverized in a ball mill, melted and kneaded in a roll mill, cooled and coarsely pulverized in a hammer mill, and then finely pulverized in an air jet type pulverizer. do. The resulting fine powder is classified to select particles of 1 to 20 microns and used as toner. A developer was prepared by mixing 0.06 parts by weight of colloidal silica and 88 parts by weight of carrier iron powder with 12 parts by weight of this toner.

When we measure the amount of triboelectric charge in this developer -
It was 9.9μc/g. The amount of triboelectric charge was measured by the so-called blow-off method. using this developer
When copied using an NP color copier, a clear magenta image with excellent spectral reflection characteristics and no fogging was obtained.

When 2,000 sheets were continuously copied using the developer obtained in Example 1, the results were good, with no deterioration in image quality such as changes in image density or increase in fog.

Example 2 The same procedure as Example 1 was carried out using the following toner composition (however, colloidal silica was not used).
0.024 parts by weight added) Tribocharge amount is -10.7μc/g
A magenta image with excellent negative chargeability and good hue was obtained.

Toner composition Polyester resin Rhodamine base FB Macrolex Red 5B Ditertiarybutylsalicylic acid chromium complex 100 parts by weight 2 〃 3 〃 4 〃 The developer obtained in Example 3 was heated at a high temperature of 80% at 35°C.
When the image was left for two days under high humidity and then imaged, a slight increase in density and a decrease in sharpness were observed, but the level was sufficient for practical use.

Example 2 When the toner was prepared in the same manner as in Example 1 with the following toner composition (however, no colloidal silica was added), a good magenta image was still obtained. Incidentally, the amount of triboelectric charge was -9.3 μc/g.

Toner composition Styrene-butadiene copolymer resin Rhodamine B base HelioOilRedR Monotertiary butyl salicylic acid chromium complex 100 parts by weight 4.5 〃 8.0 〃 9.0 〃 Comparative example 1 Styrene-maleic acid copolymer resin 100 parts by weight and rhodamine base FB1 Using .2 parts by weight,
A toner was prepared in the same manner as in Example 1. The obtained toner exhibited positive triboelectric charging properties, and when a fading test was conducted using a fade-o-meter, it was found to be inferior in light resistance compared to the toner of Example 1.

Comparative Example 2 A toner was prepared in the same manner as in Example 2, except that 3 parts by weight of CI Pigment Red was used instead of CI Solvent Red 52. A developer was prepared in the same manner as in Example 2 using the adjusted toner, and left at 35° C. and 80% high temperature and high humidity for 2 days.
When an image development test was then conducted, the image density of the obtained toner image was reduced, and the sharpness of the toner image was also reduced. Further, when a fading test was conducted using a fade-o-meter, the light resistance was inferior to that of the toner of Example 2.

Comparative Example 3 A toner was prepared in the same manner as in Example 2 using 100 parts by weight of polyester resin, 6 parts by weight of Rhodamine Base FB, 1 part by weight of Macrolex Red 5B, and 3 parts by weight of a chromium complex of ditertiarybutylsalicylic acid. The amount of triboelectric charge of the obtained toner is
-2.2 μc/g, and when an image formation test was conducted in the same manner as in Example 2, fogging was observed in the toner image, and the image density was also lower than in Example 2.

Claims (1)

[Claims] 1 CI Solvent Red 49 in toner binder resin
0.1-5wt% of compounds classified as CI Solvent Red 52 and 0.1-10wt% of compounds classified as CI Solvent Red 52
and chromium complex of alkyl salicylic acid 2~
The usage amount of the compound containing 10wt% and classified as CI Solvent Red 49 is the sum of the usage amount of the compound classified as CI Solvent Red 52 and the usage amount of the chromium complex of alkylsalicylic acid. Negatively charged magenta toner characterized in that it has the same amount or less.