JPS59172652A - Dry type electrostatic recording color toner - Google Patents

Abstract

PURPOSE:To obtain a dry type electrostatic recording functional color toner capable of forming an image having a sharp color unaffected by an underlayer color by adding a substance high in refractive index to raise a toner layer in hiding power. CONSTITUTION:This purpose is achieved by using a color toner composed essentially of a synthetic resin and a colorant, and contg. further, fine powder of a substance having >=1.6 refractive index and incompatible with this resin. White pigments having such indices and not impairing the color of the colorant are generally desirable, and it may be a colored inorg. pigment having a color resembling the used colorant. As the white pigment, e.g., rutile or anatase type titanium oxide, zinc oxide, antimony oxide, tin dioxide, zirconium oxide, zinc sulfide, lithopone, etc. are desirable, and they may be used alone or in combination. The use of titanium oxide high in refractive index is especially desirable. A preferable amt. of said substance contained in the color toner is 0.1-10wt. of the colorant.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improved color toner Ic for dry electrostatic recording, and more specifically to a dry electrostatic 1h recording improved to be suitable for so-called 7 angle color copying. Regarding color toner.

[Prior art]

To record color images using electrostatic recording, one method of color copying is generally used, which reproduces the colors of the original image using a combination of three-color separation exposure and subtractive color toner of the three primary colors (or intertones including all black). , In addition, one or more colors other than the commonly used black are used to display specific characters, figures, graphs, etc. on the screen to help emphasize or identify them, or to give them a special meaning. There is a so-called functional color method. Functional color display does not directly reproduce and record the colors of the original picture, but the free use of color allows for recording a much larger amount of information than monochromatic recordings, so depending on the purpose, it may be possible to display the original picture. Re-za (, color 1; used as a powerful means of expressing information different from one's own O),
However, in the conventional three primary color system, color toners with relatively high transparency and good color mixing properties have been used, which display many intermediate colors by overprinting toners of three colors or intermediate colors. On the other hand, in functional color, the purpose is to distinguish by color, and it is not even necessary to express intermediate colors by mixing colors. There are a variety of ways to use it, such as printing on ready-made printed materials such as printed copies of printed materials, various forms, grids, characters, figures, etc., and recording on colored paper. Not affected by I! I'n'!
14 f:C coloring is required.

With conventional highly transparent color toners, the underlying color and image can be seen through, making it impossible to obtain images with the clear colors necessary for functional color copying.

[Purpose of the invention]

The object of the present invention is to produce clear colors when transferred and fixed onto paper, without being affected by images formed with other color toners or printing inks, or by the color of colored paper. An object of the present invention is to provide a color toner for dry type one-electronic recording, which forms images and is suitable for functional color.

[Structure of the invention]

The above object has been achieved by a color toner mainly composed of a synthetic resin and a colorant, and further containing fine powder of a substance having a refractive index of 1.6 or more and incompatible with the synthetic resin.

The substance with a refractive index of 1.6 or more used in the color toner of the present invention may be a fine powder that is incompatible with the synthetic <714 fat constituting the toner, but those with a refractive index of 2.0 or more are particularly effective. . - A white pigment with a refractive index of 1.6 or higher that does not impair the color of the colorant is preferable, but colored inorganic pigments with a similar color to the colorant used may also be used. 〇 Examples of the above white pigment include rutile type titanium oxide (n=2.7), anatase type titanium oxide (n==
2.5), zinc oxide (n=2.0), antimony oxide (
n+=2.0-2.3), tin dioxide (n=2.0
), zirconium oxide (n=1.95), zinc sulfide (
n=2.36), barium sulfate (n=1.64), lithopone (n=1.7 to 2.25), etc., and these may be used alone or in combination.

Note that the above value of n is the refractive index of each pigment, and it is particularly preferable to use titanium oxide, which has a high refractive index.

The content of the substance with a refractive index of 1.6 or more in the color toner, the colorant fragments contained in the color toner,
A range of 1 to 10 weight percent is preferred, and a range of 1 to 8 percent is particularly preferred. If the amount of the substance having a refractive index of 1.6 or more is less than 0.1% by weight, there is no effect of improving the hiding property, and if it is more than 10% by weight, the color of the toner becomes lighter, which is not preferred in practice.

Examples of the synthetic resin constituting the color toner of the present invention include derivatives of acrylic acid or methacrylic acid, styrene polymers, copolymers thereof, olefin-vinyl acetate copolymers, epoxy resins, Various known synthetic resins commonly used in electrostatic recording containers can be used, such as polyester resins, polyolefins, and styrene-butadiene copolymers.

Various organic pigments, dyes, and inorganic pigments can be used as the coloring agent constituting the color toner of the present invention. For example, organic pigments such as monoazo, condensed azo, azo lake, and polycyclic pigments, The use of phthalocyanine-based materials is particularly preferred.

The color toner of the present invention also contains various charge control agents, hydrophobic silica and fatty acid metal salts to improve toner fluidity and cleaning properties, and polyethylene, polypropylene, and wax to improve fixing properties. Various additives such as those commonly used in toners may be added.

The toner of the present invention includes the above-mentioned synthetic resin, a colorant, and a refractive index of 1.
．． It can be produced by a known method generally used in toner production, which involves mixing six or more substances, other additives, etc., then melting, mixing, cooling, pulverizing, and classifying.

Multicolor recordings using color toner invented by Wood? In order to obtain the color toner of the present invention, it is sufficient to load the color toner according to the present invention into an ordinary monochrome electrostatic recording device and form an image on a ready-made copy, printed matter, colored paper, etc. by a conventional method, and then toner of each color can be obtained. You may also perform overprinting by replacing the . In addition, various known multicolor electrostatic recording devices, such as JP-A-56-2
A device such as that disclosed in the '5751 patent may be loaded with a plurality of toners according to the present invention to form an image.

[Function and effect of the invention]

The synthetic resins that make up ordinary color toners are generally 1.
It has a refractive index of around 5, and organic pigments used as colorants also have a similar refractive index, so the toner layer after m-fusion fixing has relatively high transparency. The toner must have a high hiding power that does not allow the underlying color to pass through. Even better concealment is possible to some extent by using colorant 1.1 - altar, but... - By adding a substance with a high refractive index according to the invention, it is possible to further increase the hiding power of the toner without increasing the amount of expensive Tx colorant, and it is possible to obtain images with clear coloration that is not affected by the color of the base. .

This will be explained in detail below using examples.

[Example 1] A red toner was prototyped using the following formulation (numbers indicate parts by weight).

Sample rot I n m iv synthetic resin 1) 100 100 100 100 red pigment 2)
3 3 3 31) Methylene-methyl methacrylate copolymer with a composition ratio of 50:20:30 2) PV-
Red) f4BO1 (manufactured by Hoechst Javan) Ba lake-based red organic pigment sample 1. IJ is a toner according to the Wood invention, ■ is a toner 9 containing a white pigment with a low refractive index, and ■ is a control sample in which the white pigment is not eaten away.

The raw materials for the above formulation were prepared in a ball mill for 10 hours, then melted and kneaded with a twin-screw extruder (PCM-30, manufactured by Ikegu Iron Works), cooled, and finely pulverized with a jet mill, followed by a zigzag classifier (manufactured by Albine). ) to obtain an average particle size of 12
Four types of red toners with a diameter of ~13 μm were obtained.

Above test *: L 24 g and spherical key
-1, manufactured by Shinto Greater) was mixed to prepare a present agent, which was loaded into an electrostatic copying machine U-BIx-3000 (manufactured by Konishi Roku Photography 9) and subjected to a practical test. In the practical test, the same test pattern was copied on white paper and black paper in order to observe the influence of the background color.
Color tone was visually evaluated.

All of the images on the white paper had a clear red color, but there were large differences in the color of the images on the black paper, as shown in Table 1.

(Table 1) Sample A llll1lIrV Refractive index of white pigment 2.7 2.0 1.5 -
Coloration on white paper ○ ○ OO Coloration on black paper ○ ○ △× ×○ Clear coloration.

ΔX: The color of the image is darkened, which is not desirable for practical purposes.

×　The black base color is transparent and cannot be put to practical use.

As shown in the table, Samples I and Il containing the white pigment with a refractive index of 1.6 or more according to the present invention form images with clear colors that are not affected by the base, whereas the samples containing a pigment with a low refractive index ■
The image obtained by the comparison sample ① to which no pigment was added appeared to be indistinct due to the black background being transmitted through it, and was not suitable for practical use.

[Example 2] A yellow toner was experimentally produced using the following formulation (numbers indicate parts by weight).

Sample pain V VI Synthetic resin 1) 100100 Yellow pigment 2) 33 Zinc oxide 0.06 - 1) Styrene-butyl methacrylate composition ratio 85:
Copolymer of No. 25 2) Sumitomo Fast Yellow HRT (manufactured by Sumitomo Chemical) Sample (2) is a toner according to the present invention, and Sample (2) is a control sample. The particle size was approximately 1.2 t by the same method as in Example 1.
A trrL toner was obtained. The practical performance of each toner was evaluated using the method of Example 1, and the results are shown in Table 2. t
.

Table 2 Test Ra< V V
Color development on I white paper - H ○ ○ Color development on black paper ○ × The toner V according to the present invention had a clearer color development on black paper than the comparison sample toner ①. The color development of the comparison sample (2) on black paper was extremely poor and could not be put to practical use.

[Example 3] The following formulation (numbers indicate the overlapped portions) produced blue and -L□
□Yes.

Sample waste ■ ■ Synthetic resin 1) 100 Zo.

Blue pigment 2) 33 Titanium oxide 0.09 - 1) Styrene-butyl methacrylate composition ratio 85:
2) Kayaset Blue N (manufactured by Nippon Kayaku Co., Ltd.) Sample 2 is a toner according to the present invention, and 2 is a control sample.

A toner was prepared in the same manner as in Example 1, and the practical performance was evaluated, and the results shown in Table 3 were obtained.

Table 3 Sample 16 ■ % ■ Coloration on white paper 0 0 Coloration on black paper ○ × Toner ■ made from Kibatsu' IIJ K forms an extremely clear image of the mortar even on black paper, whereas Comparison test f1■
The 1iIiii image obtained by the method was unclear because the black color of the base was transmitted through it, and could not be put to practical use.

Agent Yoshimi Kuwahara

Claims (1)

[Scope of Claims] (1) Dry mold containing synthetic resin and colorant as main components
Color toner for dry electrostatic recording (2), which is characterized in that the color toner contains fine powder of a substance having a refractive index of 1.6 or more and which is not cofermentable with the synthetic resin. The color toner for dry electrostatic recording according to claim 1, wherein the content of the substance having a refractive index of 1.6 or more is 01 to 10% by weight of the colorant tube. (3) The above-mentioned substance having a refractive index of 1.6 or more is a white pigment having a refractive index of 1.6 or more! li′
i! Color toner for dry electrostatic recording as described in item 1 (4)
- Claims in which the white pigment is titanium oxide, zinc oxide, antimony oxide, tin dioxide, zirconium oxide, zinc silicide, barium sulfate, lithopone, or a mixture thereof [4N Dry electrostatic charge according to paragraph 1] Color toner for recording. (5) The color toner for dry stationary recording according to claim 1, wherein the white pigment is titanium oxide.