JPS62163061A - Electrophotographic toner - Google Patents

Abstract

PURPOSE:To enable copies to be maintained in high image quality at the time of high-speed successive copying by incorporating a specified metal salt as a colorless controlling agent. CONSTITUTION:The metal salt to be added is represented by formula I and II in which each of X and Y is H, halogen, nitro, optionally substituted alkyl, hydroxyl, alkyl ether, alkyl ester, alkylamino, or benzoylamino, and each of X and Y may be same to each other; M is a mono- - tetra-valent metal atom; each of (a), n, and n' is an integer of 1-4, and n and n' may be same. This colorless metal salt is extremely good in compatibility with various kinds of resins, and its addition to a toner permits extremely sharp and stable copies to be obtained even at the time of high-speed successive copying from the initial stage of copying to a stage after repeated copying operations.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a toner for developing electrostatic latent images in electrophotography, electrostatic recording, and the like.

(Prior art) In electrophotography, a latent image is formed on a photoconductor made of a photoconductive substance, and this is developed with a powder developer to make it visible.
Furthermore, a method of fixing onto paper using heat, a solvent, or in some cases pressure is common. The developer used in such electrophotography is a mixture of fine particle powder consisting of resin and colorant called developer powder or toner, microscopic glass beads called carrier, iron powder, iron powder coated with various resins, etc. be done. Furthermore, in this case, a method using extremely fine ferrite or magnetite as a carrier is called a -component system, and can be distinguished from the former. The present invention relates to developer powder called toner of these developers. The photoconductor layer can be positively or negatively charged so that exposure under the original produces a positive or negative electrostatic latent image.

Therefore, a positively charged dashi-positive image is generated on the negative electrostatic latent image. However, when a positively electrostatic latent image is developed with negatively charged developer powder, the black and white tones are reversed and a negative image of the original, that is, a digital negative image is obtained. As described above, there are two types of developer powder for electrophotography: positively charged developer powder and negatively charged developer powder.

(Problems to be Solved by the Invention) Among these, the present invention relates to negatively charged developer powder.

Generally, developer powder is fine particles made of synthetic resin mixed with colorants such as dyes and pigments. Conventionally, in developing powders, it has not been possible to obtain desirable chargeability with the resin used alone, and charge control agents such as dyes, pigments, or metal complex compounds have been used to impart appropriate chargeability to the resin. Ta.

Currently known charge control agents that impart a positive charge to toner include nigrosine dyes, and those that impart a negative charge include Japanese Patent Publication No. 41-6397, Japanese Patent Publication No. 43-27596, Examples include Japanese Patent Publication No. 51-29827. All of these materials are colored substances and are limited to developers having the same color tone as the dye, and their application is extremely difficult, especially in the case of color copying.

Next, as a colorless control agent, Japanese Patent Publication No. 55-42752
Publications, Japanese Unexamined Patent Publication No. 57-104940, etc. can be mentioned. However, in both cases, since these compounds themselves exhibit a pale yellow to orange-yellow color, they have the disadvantage that they affect the tones of toners other than yellow in color copies, making the tones of the copied image unclear. have,
In addition, the compatibility with the various resins used in toners is still insufficient, resulting in uneven charging, resulting in toners lacking uniformity, and causing white spots and background stains when developed. It causes Furthermore, toners to which these compounds are added reduce the amount of charge in environments of high temperature and high humidity, and are insufficient in maintaining high-quality copies, especially during high-speed and continuous copying.

(Means for Solving the Problems) The present inventors have completed the present invention as a result of repeated studies on colorless compounds that do not have these drawbacks.

That is, the present invention relates to the following general formula [(wherein, , represents a benzoylamino group, M represents a monovalent to tetravalent metal, a represents an integer of 1 to 4, n and n' are 1
It represents an integer of ~4, and X and Y, and n and n' may be the same. ) is an electrophotographic toner characterized by containing a metal salt represented by:

The colorless control agent of the present invention has extremely good compatibility with various resins, and toners containing these compounds produce extremely clear and stable copied images not only in initial copies but also in high-speed and continuous copying. can be obtained.

The metal salt compound used in the developing powder of the present invention can be synthesized by a conventional method.

That is, the following compound (where X, Y, n, n' are as defined above.

) in a solvent such as water or alcohol with a metal salt having a specified molar equivalent to the above compound, the metal salt compound according to the present invention can be obtained in high yield.

The toner of the present invention contains a binding substance and a coloring substance in addition to the metal salt compound. Examples of the binding substance that can be suitably used in the toner of the present invention include styrene and its substituted substances such as polystyrene and teribinyltoluene. styrene-substituted styrene copolymer, styrene-acrylic ester copolymer, styrene-methacrylic ester copolymer, styrene-acrylonidonyl copolymer, polyvinyl chloride, polyethylene , silicone resin, jelly ester, polyurethane, pyramid, niboxy resin,
Modified rosin, phenolic resin, etc. can be used alone or in combination.

Examples of coloring substances include C,1, Pigment Yellow 12, C,1, Solvent Yellow 16, c, and r.

Dis/Guichi's Yellow 33, C,1, Pigment Red 122, C,1, Solvent Red 19, C,1, Pigment Blue 15, C1■, Pigment Black 1,
C,1, Solvent Black 3, C,1, Solvent Black 22, carbon black, etc. can be used. Another feature of the present invention is that by using it in combination with a colored dye that has the effect of a conventionally known charge control agent, the shortcoming of the known charge control agent's lack of long-term stability can be significantly improved.

A two-component dry developer requires a carrier component, and iron powder carriers or various resin-coated iron powder carriers can be used. Furthermore, in order to prepare a -component type dry developer, magnetites can be added during kneading of the binder resin.

(Example) Hereinafter, the present invention will be explained in detail by way of an example.
Represents parts by weight.

Example 1 10 parts of 3.5-ditertiarybutyl salicylic acid to 50 c
Add 100 parts of ethanol water, dissolve at 60-65°C, gradually add 2 parts of calcium carbonate, stir at the same temperature for 2 hours, filter the precipitate, wash with water, dry, and form a solution expressed by the following formula. 11 parts of calcium 3,5-ditertiarybutylsalcylate as a white fine powder was obtained.

Production of toner: To 100 parts of styrene-acrylic copolymer resin, 6 parts of carbon black (Regal 300R, manufactured by Cabot Corporation) and 1 part of the synthesized 3,5-ditertiarybutyl salicylic acid calcium salt were added, and after thorough mixing, The mixture was melted by heating, cooled, and then ground in a ball mill to obtain a fine, negatively charged developing powder.

Next, add this developing powder to a diameter of 100 to 15 mm at a weight ratio of 5:100.
A developer was obtained by mixing with iron powder of 0 μm.

Next, a positive electrostatic latent image is formed on a selenium photosensitive plate charged by corona radiation at 8K (+5000V), and this digital image is transferred to paper and heat-fixed to create a clear and clear image without fogging. A clear halftone image was obtained, and even after the 70,000th continuous copying (running), there was almost no change in the development characteristics of the toner, and the same good quality as the initial image was obtained. In addition, the toner charge amount was measured using the blow-off method, and the initial charge amount was -30.4 μc/f, and the toner charge amount at the 70,000th sheet of running was -30.1 μc/f, which was almost the same as the initial value. -2 for charge distribution
At 9.8 to -30.5 .mu.c/f, the toner was very uniform, and both were extremely excellent as toners.

Example 2 The following metal salt compound was synthesized according to Example 1.

A developer prepared in the same manner as in Example 1 using 1 part of this compound produced clear images with no fogging and clear halftones, and even after 70,000 consecutive copies (running), the toner remained intact. There was almost no change in development characteristics, and good copies were obtained that were the same as the initial images. In addition, the amount of charge on the toner was measured using the blow-off method, and the initial charge was 1-28.5μc/r.The toner band at the 70,000th run! The difference is -28,4
There was almost no difference in .mu.c/l from the initial value, and the charge distribution was uniform from -277 to -28.5 .mu.c/f, and both were extremely excellent as toners.

Examples 3 to 8 Using the developer composition shown in the following table, the same procedure as in Example 1 was carried out. ) Got a ner. The image properties and charging characteristics of these toners are also summarized in the table.

Claims (1)

[Claims] The following general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [(In the formula, X and Y are hydrogen atoms, halogen atoms, nitro groups, alkyl groups Represents a hydroxyl group (including a substituted alkyl group), an alkyl ether group, an alkyl ester group, an alkylamino group, or a benzoylamino group, M represents a monovalent to tetravalent metal, a represents an integer of 1 to 4, and n and n' is 1
It represents an integer of ~4, and X and Y, and n and n' may be the same. ) An electrophotographic toner characterized by containing a metal salt represented by: