JPS62166359A - Toner for electrophotography - Google Patents

Abstract

PURPOSE:To obtain a color toner for positively charged electrophotography having high transparency, age stability, superior fluidity, fixing characteristics, and reduced contaminating effect for white base part of obtd. picture image. CONSTITUTION:The titled toner contains a compd. expressed by the formula (I) wherein X is Cl or So<->3; m is 1 or 2, n is 1 or 2; M is Mg, Ca, or Ba. When X is Cl, m is 1, and n is 2, respectively. When X is SO<->3, m is 2 and n is 1, respectively. the compd. (I) functions as a coloring agent and a positive charge controlling agent, having superior compatibility with a binder. When (I) is contained in a toner, the specific electric charge of the toner is increased as well as the moisture resistance of the toner is improved. Accordingly, the age stability of the toner is increased and the toner has extremely high capacity for forming picture image repeatedly. The formula (I-1) shows specific examples for the compd. (I).

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to toners. More specifically, the present invention relates to color toner for electrophotography.

Conventional technology Electrophotography involves the process of forming an electrostatic latent image on a photoreceptor made of a photoconductive substance, etc., and a toner and carrier made of a thermoplastic resin, colored fine particles, charge control agent, etc. It consists of a process in which the electrostatic latent image is visualized using a powdered developer. Such toner is made of a binder mainly made of thermoplastic resin, a coloring agent such as a dye or a pigment, etc.
Mix a charge control agent (a substance that controls the charge of the toner during frictional charging with the carrier), etc., and add 10 to 50μ
Since some photoconductive substances are positively or negatively charged, there are two types of toners: positively charged toners and negatively charged toners, and negatively charged toners are usually used. However, the use of positively charged toner has recently increased. Furthermore, in color electrophotography, a color image is obtained by exposing an original to light using a color separation filter and repeatedly using a color developer containing color toner (yellow toner, magenta toner, cyan toner, etc.) multiple times. The characteristics required for such color toners include transparency for multicolor overlay, excellent spectral reflection characteristics for faithfully reproducing originals, and general Toners are required to have excellent properties such as stability over time, fluidity, and fixability.

Conventional color toners use various oil-soluble dyes as colorants,
It is composed of organic and inorganic pigments, nigrosine dye as a D charge control agent, various quaternary amines (Journal of the Japan Society of Electrostatics, Vol. 4, No. 3, p. 144, 1980), etc., but conventional toners include the following: Due to these drawbacks, there were few satisfactory color toners.

Although oil-soluble dyes have good compatibility with binders, they have extremely poor bleedability (the ability of the dye to ooze out from the resin).
When the images obtained by toners using this material come into contact with synthetic resins (films, sheets), the images are disturbed by the plasticizers contained in them, causing hot water contamination.
Reduces image storage. Although pigments have good bleedability, they have poor transparency and are not preferred as coloring agents for color toners. In addition, the nigrosine dye used as a control agent is black in itself and cannot be used in toners of colors other than black, and colorless control agents such as quaternary amines have poor moisture resistance, resulting in poor toner stability over time ( As a result, there is a drawback that the ability to repeatedly form images is poor.As described above, no coloring agent or charge control agent, particularly a positive charge control agent, that exhibits excellent effects as a component of color toners has yet been found.

It is desired to develop a positively charged color toner for electrophotography that has high transparency (excellent stability over time, fluidity, and adhesion), and has low hot water contamination of viewed images.

Means for Solving the Problems The present inventors have achieved the present invention as a result of intensive research to solve the five problems mentioned above. Namely, the present invention is based on the following formula (1) ( In formula (1), X is CI or SOl, m is 1 or 2, and
represents 1 or 2, and M represents Mg, Ca or Ba, respectively. However, when X is C1, m represents 1 and n represents 2, respectively.
Provided is an electrophotographic toner containing a compound represented by the following formula: when X is SO;

The compound of formula () functions as a coloring agent and a positive charge control agent, and has good compatibility with a binder. When this compound is included in a toner, the toner has a high specific charge amount (and moisture resistance Based on its excellent properties (because the toner has high stability over time, its ability to repeatedly form images is very good).

Specific examples of the compound of formula (1) used in the present invention include the following.

Color toners containing the compound of formula (1) can be prepared by conventional methods, such as those described below.

That is, the compound of formula (1), a binder, and if necessary, a metal soap are mixed, kneaded while melting using a device capable of heat mixing such as a heating kneader or two rolls, and then cooled and solidified, and then processed by a jet mill, a ball mill, etc. 1-5 depending on the crusher
Prepared by grinding to a particle size of 0μ.

In the above, as the binder, polystyrene resin, styrene-acrylate copolymer, epoxy resin, phenol resin, polyester resin, etc. are used, and as the metal soap, zinc stearate, barium stearate,
Magnesium stearate, calcium stearate,
Examples include aluminum stearate, barium laurate, zinc laurate, barium ricinoleate, calcium ricinoleate, calcium montanate, calcium oleate, zinc 12-hydroxystearate, zinc oleate, and the like. The compound of formula (1) and the metal soap used as needed are each used in an amount of 0.5 to 20 parts by weight, preferably 1 to 5 parts by weight, per 100 parts by weight of the binder.

Note that a fluidizing agent such as silicon oxide, an antifogging agent such as mineral oil, etc. may be added to the toner as necessary.

The toner of the present invention is used as a developer for electrophotography by mixing with a carrier prepared from iron powder or the like in a ratio of 3:97 to 50:50 (toner:carrier, weight ratio) by a conventional method.

The compound of formula (1) provides color toners with good transparency and no hot water stains, and also has chargeability, which is an important property as a charge control agent, that is better than that of colorless control agents such as known metal complexes of salicylic acid. , 4 as measured by a plow-off measuring device.
0-50μc/g Nigrosine dye 10-20μc/g
c/g, whereas it is at a high level of 100 to 120 μc/H, making it possible to prepare color toners that give extremely clear images with excellent hot water stain resistance.

Examples Below, the present invention will be specifically explained with reference to examples.
"Parts" means parts by weight unless otherwise specified.

Example 1 was melt-mixed in a heating kneader, cooled, and coarsely pulverized in a thermos mill, and then pulverized and classified to 5 to 10μ in a jet mill equipped with a classifier to obtain the color toner of the present invention. Ta. The obtained toner was coated with approximately 200 mesh of iron powder (carrier: TEFV-200/300 manufactured by Nippon Iron Powder Co., Ltd.).
5 parts: 95 parts (toner: carrier, weight ratio)] O
The mixture was mixed for 10 minutes in an Occ plastic container to prepare a developer. When the initial specific charge amount of the toner of this developer and the specific charge amount after being left in 100% humidity for one week were measured using a blow-off device, they were +22 μc/g and +22 μc/g, respectively.
Met. Furthermore, this developer is used in a copying machine (RICOP).
When I made 5,000 copies using Y FT-505 (manufactured by Nishikki Ricoh), there was no difference at all between the developer after leaving it in 100% humidity for a week and the previous developer (clear images with excellent gradation). A contamination test was conducted on the 5000th copy and the following results were obtained.

(Support) Stainability test: Based on JIS L-0823, a soft vinyl chloride white sheet (50 parts of polyvinyl chloride resin,
(composed of 45 parts of dioctyl phthalate and 5 parts of titanium oxide) 100 times. The degree of contamination of the vinyl chloride sheet after rubbing was determined using the JIS contamination gray scale. The judgment value is on a 5-level scale from 1 to 5, and the higher the value, the less contamination there is.

Example 2゜ was melt-mixed using two rolls, cooled, coarsely ground using a hammer mill, and then crushed in a jet mill equipped with a classifier.
The color toner of the present invention was obtained by pulverizing and classifying to ~10μ.

The obtained toner was mixed with about 200 mesh of iron powder carrier at a weight ratio of 10+90 (1-ner:iron powder carrier) to prepare a developer. Example (1) using this developer
Similarly, when we measured the specific charge amount before and after leaving it in 100% humidity for one week, it was +2146μc/g and +21, respectively.
．． It was 2 μc/g. When 5,000 copies were made in the same manner as in Example 1 using the toner obtained in this example and the developer prepared in 5 above, there was no deterioration in the quality of the copied images even during continuous copying, and excellent images were obtained. A copy was obtained.

Furthermore, the staining test results for the 5,000th copy are shown in the table below, and almost no hot water staining was observed.

Example 3° is ground in a mixer for 2 minutes. 6 parts of the treated product and 200 parts of epoxy resin were mixed and pulverized in a ball mill, then melted and kneaded in a heating kneader, cooled and solidified, pulverized in a jet mill, and classified into 5 to 10 microns to obtain the color of the present invention. Got toner. Example (1) using the obtained toner
A developer was prepared in the same manner as above, and the specific charge amount of the toner was measured before and after leaving it for one week in 100% humidity.
They were 22.2 μc/g and +21.8 μc/g.

When copies were made in the same manner as in Example 1 using the developer prepared from the color toner of the present invention, there was no deterioration in image quality even after 5000 copies were made, and copies with high gradations were obtained. Furthermore, when a staining test was conducted on the 5,000th copy, almost no hot water staining was observed.

Examples 4 to 9 Color toners were prepared in the same manner as in Example 1 using the compounds and metal soaps shown in the column of purchase formula in Table 1, and then a developer was prepared in the same manner as in Example 1. Next, the specific charge amount was measured in the same manner as in Example 1, and the resulting image was subjected to a staining test. The results are shown in Table 1.

The toners using any of the compounds exhibited small changes in the zone density over time, and the resulting images had very low staining properties.

In addition, the specific charge amount (μc/g) in Table 1 is 1 in 100% humidity.
These are the measured values of E9 before and after being left for a week.

Comparative Example 1 A developer was prepared in the same manner as in Example 1 using Nigrosine (trade name Oil Black BY) instead of the compound represented by formula (2) in Example 1, and the specific charge amount was When a contamination test was conducted, the results shown in Table (1) above were obtained. Furthermore, when copies were made in the same manner as in Example 1 using this developer, the 5,000th image showed a fogging phenomenon and lacked sharpness compared to the first image, and a decline in quality was observed in continuous copying. Ta.

Comparative Example 2 A developer was prepared in the same manner as in Example 2 except that CI and Disperse Yellow 1 O9 were used in place of the compound represented by formula (3).

When copies were made using this developer, the image density was clearly low and the clarity was lacking. The specific charge amount of the toner of this developer and the results of the image staining test were as shown in Table (1) above.

From the above comparative tests, it is clear that the toner containing the compound of formula (1) has a large specific charge amount, good stability over time, and provides images with less hot water staining.

Effects of the Invention A yellowish toner was obtained which provides a copy image with excellent white background stain resistance in electrophotographic copying and provides an electrophotographic developer with excellent specific charge stability over time.

Claims (1)

[Claims] (1) The following formula (1) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (1) (In formula (1), X represents Cl or SO^-_3, m represents 1 or 2, and n represents 1 or 2. , M represents Mg, Ca or Ba, respectively.However, when X is Cl, m represents 1 or n represents 2, and when X is SO^-_3, m represents 2 or n represents 1, respectively) An electrophotographic toner characterized by containing a compound represented by