JPH0352860B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a developer for electrostatic latent images in electrophotography, electrostatic printing, and electrostatic recording, or a coloring composition used in the production thereof. The present invention relates to a coloring composition used as the image recording developer.

More specifically, in an electrostatic latent image developer containing a dye such as a pigment or dye, various defects caused by the charge and amount of charge brought about by the dye can be avoided by selecting a dye with a specific structure as the dye. This was improved by.

(Prior Art) In general, when pigments such as organic pigments or dyes are rubbed against a carrier used in an electrophotographic developer, their charging properties change in various ways depending on their structure. For example, copper phthalocyanine blue pigments, quinacridone pigments, and the like exhibit positive chargeability upon friction with a carrier, while copper phthalocyanine green pigments and the like exhibit negative chargeability.

(Problems to be Solved by the Invention) When a dye is used in a dry developer for an electrophotographic copying machine, the dye is dispersed in a resin dispersion medium along with other additives as necessary, and then finely ground. ,
The surface of crushed particles is unavoidably affected by the dye used. In particular, when a pigment is used, fracture occurs at the interface between the pigment and the resin, and the pigment surface may be exposed on the particle surface.

Further, in the developer for an electrophotographic copying machine, the dye used in the developer is also limited depending on the hue and tone of the desired copied image.

Therefore, if a negatively charged developer is required and the dye selected based on the hue of the required copy image is positively charged when it rubs with the carrier, the developer It has a defect in that the chargeability of minute portions on the surface of the particles and the chargeability between each particle lacks uniformity.

In view of the defects of electrostatic latent image developers as described above, the present inventors conducted various studies on the structure of dyes in order to satisfy the above conditions. The present invention was completed based on the finding that excellent effects can be exhibited even under the conditions described above by using the compound as an agent.

(Means for Solving the Problems) That is, the present invention provides a coloring composition for image recording comprising a dye and a resin dispersion medium, characterized in that the dye is a dye represented by the following structural formula. It is a coloring composition for

R in the formula is a hydrogen atom or a lower alkyl group, and n is an integer of 1 or 2.

To explain the present invention in detail, the present invention uses
The dye represented by the above structural formula, which mainly characterizes the present invention, can be obtained, for example, as follows. (However, % and parts are based on weight.) 33 parts of 35% hydrochloric acid, 180 parts of water and 18 parts of 4-aminophthalimide are mixed and stirred for 30 minutes. Next, add ice to make the liquid volume 230 parts and adjust the temperature to 0-5°C.
Add 30 parts of water to which 8.2 parts of sodium nitrite has been added and diazotize for 60 minutes. On the other hand, add 24 parts of acetoacetomethaxylidide to 5 parts of sodium hydroxide.
Dissolve in an aqueous solution of 1 part and 400 parts of water. to this
22 parts of 90% acetic acid is diluted 3 times with water and added dropwise. Prepare a subsoaking solution at a temperature of 10°C and a liquid volume of 500 parts. The above diazo solution is dropped into the subsoaking solution for about 90 minutes and coupled. Stir for 30 minutes and bring the pH to 3.5-4.0. 95
The mixture was heated to ℃ and stirred for 60 minutes, filtered and washed with water to obtain a pigment paste cake. It is dried at 100°C and pulverized to obtain a yellow pigment powder in which R is methyl and n=2 in the above general formula.

The resin dispersion medium used in the present invention is a dispersion medium for the above-mentioned dye, and also acts as a fixing agent for the dye when used as a developer.

All conventionally used resin dispersion media can be used, such as polystyrene, styrene-(meth)acrylic acid ester copolymer, styrene-maleic acid ester copolymer, and (meth)acrylic acid ester copolymer. Acrylic acid ester polymers and copolymers, styrene-diene copolymers, polyethylene, polypropylene, ethylene-
Addition polymer resins such as vinyl acetate copolymers and ethylene-acrylic acid ester copolymers, condensation resins such as polyester resins, epoxy resins, and phenol resins, modified resins such as rosin esters and maleated rosin esters, Low-molecular solids such as petroleum resins, higher fatty acid waxes, higher alcohols, higher fatty acids, paraffin waxes, carnauba waxes, and Sierra waxes can be used alone or in combination.

In the present invention, the content of the pigment represented by the above structural formula in the coloring composition containing the resin dispersion medium and other additives varies depending on the purpose of use, and the content of the pigment represented by the above structural formula is different depending on the purpose of use. In solid, pasty or liquid compositions containing: about 80% to 10% by weight, preferably 60% by weight
~30% by weight, and when used as a coloring agent for electrophotographic developers, it is approximately 15% to 2% by weight, preferably 10% to 3% by weight, and most preferably depending on other purposes. Use in content.

The coloring composition for image recording of the present invention can be used in various ways depending on the purpose.

One example is one that contains pigment at a high concentration and is used to facilitate the subsequent process by thoroughly kneading and dispersing it in advance, or by adjusting the color. It can be used in any solid form such as fine powder, sheet, or small lump, or in any form such as paste or liquid.

Another example is a composition used as a final image recording developer, such as so-called dry developer, wet developer, electrostatic developer, etc. Dry developer is also a two-component developer. It is divided into two types: developer and one-component developer.

A ferromagnetic material is mainly used in one-component dry developers. These ferromagnetic materials are also added to the coloring composition of the present invention as necessary,
Any of the ferromagnetic fine particles conventionally used for magnetic developers can be used.

Examples include oxides such as triiron tetroxide powder and sesquiferric oxide powder, metal powders such as iron, nickel, and cobalt, and the shape is not limited to cubic, acicular, etc.

Further, the plasticizing material added as necessary is, for example, one used in a pressure fixing type developer, and
Examples include plasticizers, oils and fats, low melting point waxes, petroleum resins, and liquid oligomer resins.

As a solvent, in the case of a paste or liquid composition containing a high concentration of pigment,
Depending on the manufacturing process or method of use, aliphatic, alicyclic, aromatic hydrocarbons, halogenated hydrocarbons, esters, ketones, glycol ethers, alcohols, water, etc. may be used, but are not particularly limited. .

When used as a wet liquid developer medium, conventionally known highly insulating petroleum solvents such as Isopar H, Isopar G (Etsuo Standard Co., Ltd.) Ciel Sol 71 (Ciel Sekiyu Co., Ltd.) and kerosene may be used. etc.

In addition, if additional dyes are required, they are appropriately selected from conventionally known pigments or dyes and used together with the dyes used in the present invention. For example, organic pigments or dyes include phthalocyanine, azo, anthraquinone, perinone/perylene,
Examples of indigo/thioindigo pigments, dioxazine pigments, quinacridone pigments, isoindoline pigments, aniline black pigments, and carbon black pigments include titanium oxide pigments, iron oxide pigments, calcined pigments, dark blue pigments, and metal powder pigments. Examples include extender pigments.

In addition, when used as an electrophotographic developer, conventionally known charge control agents, cleaning agents, developer fluidity improvers, etc. can be added.

(Functions/Effects) Since the coloring composition for image recording of the present invention has selected the dye represented by the above structural formula as its dye component, when it is finally used as a coloring composition for image recording, the electrostatic charge between particles is It is possible to reduce gender dispersion. Even when used as a liquid developer, the interfacial potential is constant and the phenomenon can be stable for a long time.

Next, the present invention will be specifically explained with reference to Examples. In the text, parts and percentages are based on weight unless otherwise specified.

Example 1 30 parts of the dye represented by the above structural formula was added to styrene.
Methacrylic copolymer (softening point: approx. 110℃, glass transition point: approx. 56℃, weight average molecular weight by GPC method: approx. 90,000)
The pigment was sufficiently kneaded with 70 parts using a triple roll to disperse the pigment. After cooling, the mixture was crushed to obtain a coarse powder of the highly concentrated colored composition of the present invention containing a pigment at a concentration of 30%.

Next, 20 parts of the highly concentrated coloring composition containing the dye obtained above was kneaded with 80 parts of the styrene-methacrylic copolymer used above in accordance with a conventional method, cooled, pulverized, and further finely pulverized with a diet mill. , Classify and 5~
A fine powder of the colored composition of the present invention of 30 microns was obtained. The amount of triboelectric charge of this colored composition was measured and was found to be -8.2 microrons/gram.

Colloidal silica was added as a fluidizing agent to the above red resin fine powder, and the mixture was thoroughly mixed in accordance with a conventional method to form an electrophotographic dry developer. The mixture was mixed with the magnetic iron of the carrier and used in an electrophotographic copying machine for negative charge developers. Upon copying, a clear and stable copy image was obtained.

Example 2 30% of the dye represented by the above structural formula of Example 1
20.8 parts of a highly concentrated coloring composition containing 15 parts of an acrylic ester resin soluble in an aliphatic hydrocarbon solvent
A concentrated colored liquid of the present invention was prepared by adding 100 parts of Isopar G along with 100 parts of Isopar G, further adding glass beads, and shaking the mixture in a paint shaker for 20 hours to disperse the mixture. Five parts of this concentrated colored liquid was added to 1 liter of Isopar G and dispersed to obtain an electrophotographic wet type developer of the present invention. When this was copied using a wet-type electrophotographic copying machine, a clear copy image with a subdued color tone was stably obtained.

Claims (1)

[Scope of Claims] 1. A coloring composition for image recording comprising a dye and a resin dispersion medium, characterized in that the dye is a dye represented by the following structural formula. [R in the formula is a hydrogen atom or a lower alkyl group, and n is an integer of 1 or 2. ] 2 Claim 1, which is a solid, paste or liquid composition containing a pigment at a high concentration
The coloring composition for image recording as described in . 3. The coloring composition for image recording according to claim 1, which is a solid fine powder developer. 4. The coloring composition for image recording according to claim 1, which is a liquid developer.