JP3044363B2 - Magenta developer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magenta developer,
More specifically, the present invention relates to a magenta developer useful for electrophotography, electrostatic recording, electrostatic printing, and the like.

[0002]

2. Description of the Related Art
The electrophotographic process involves uniformly charging a photoconductive insulating layer, then exposing the layer, dissipating the charge on the exposed portions to form an electrostatic latent image, and further forming the electrostatic latent image. The image is visualized by adhering a fine powder having a colored charge called a toner to the image (development step), and the obtained visible image is transferred to a transfer material such as transfer paper (transfer step). A method for fixing the toner permanently by pressure or other suitable fixing method (fixing step) is known (U.S. Pat. Nos. 2,221,776 and 2,297).
Nos. 691 and 2357809).

The developing methods applied to the electrophotographic process are roughly classified into a dry developing method and a wet developing method. The former includes a method using a one-component developer and a method using a two-component developer. Depending on the type of toner transport system, magnetic brush development using magnetic powder as a carrier, cascade development using a rather coarse bead carrier, and glass fiber may be used depending on the type of toner transport system. There is a fur brush developing method to be used.

As a toner applied to these developing methods, a fine powder in which a coloring agent such as a dye or a pigment is dispersed in a natural or synthetic thermoplastic resin has been used.

In the case of a method using a two-component developer, the toner is usually mixed with carrier particles such as glass beads and iron powder. At this time, the toner is held on the carrier by electrostatic attraction caused by friction, and an electrostatic latent image is formed. Transported to the surface. The polarity of toner charging depends on the charging polarity of the electrostatic latent image,
A clear polarity, positive or negative, and an appropriate charge are required. In order to allow the toner to have a desired charge, the frictional charging properties of the carrier and the material of the surface thereof and the resin which is a component of the toner can be used. However, only by this method, the charge amount of the toner is small, and It is difficult to quickly reach a desired charge amount. In such a case, an image obtained by development is liable to cause background fog and is unclear. Therefore, in order to quickly and impart a desired charge amount to the toner, a charge control agent for controlling chargeability is added.

On the other hand, a color toner in which various dyes and pigments are dispersed or dissolved in a binder resin is used. Color toners, especially toners for reproducing full-color images using three primary color toners, not only have good basic performance including the above-described chargeability, but also reproduce the colors of the original images, It is important that the spectral reflection characteristics of each color be close to an ideal curve and reproduce black with extremely low saturation. Further, not only the spectral reflection characteristics but also the projection reproducibility of the image and color transferred and fixed to the transparency for the overhead projector (OHP), that is, the transparency and the spectral transmittance are required to be good.

However, when the charge control agent is used, a change in hue and a decrease in chroma due to coloring of the charge control agent occur,
Further, the dispersibility of the charge control agent in the binder resin is deteriorated, so that the transparency is reduced, and a clear full-color image cannot be obtained particularly when used for OHP.

Therefore, there has been a demand for a magenta developer which maintains stable chargeability even when stored for a long period of time, exhibits excellent maximum density and halftone reproducibility, and provides good transparency.

An object of the present invention is to improve the charge stability, maximum density, halftone reproducibility, and transparency after such long-term storage, and furthermore, to improve the hue of the image and prevent fading after image formation. An object of the present invention is to provide a magenta developer which is unlikely to occur.

[0010]

Means for Solving the Problems The present inventors have conducted intensive studies in view of the above circumstances, and as a result, the combination of a specific coloring agent and a charge control agent has a favorable image hue and causes fading after image formation. The inventors have found that a difficult magenta developer can be obtained, and have completed the present invention.

That is, the gist of the present invention is to provide (1) a magenta developer containing a colorant comprising a chromatic dye or pigment, a toner containing a binder resin and a charge control agent, and a coated carrier; But C.I. I. Pigment Red 122, and the binder resin has a softening point of 90 to 1 according to a ring and ball method.
It is a polyester resin at 10 ° C., and the charge control agent is represented by the following general formula (I)

[0012]

Embedded image

(Wherein M represents lithium, sodium or potassium), a metal salt of a benzylic acid derivative represented by the formula: wherein the coating material of the carrier is a silicone resin or a silicone resin obtained by dispersing a conductive powder. Magenta developer characterized by being an acrylic resin, (2) C.I. I. Pigment Red 122 is used in an amount of 1 to 10 parts by weight with respect to 100 parts by weight of the binder resin, and (3) the amount of the metal salt of a benzylic acid derivative used is 0.1-5 for 100 parts by weight of resin
The magenta developer according to the above (1) or (2), which is a part by weight.

In the present invention, the polyester resin contained in the toner as the binder resin is synthesized by a polycondensation reaction between a polycarboxylic acid and a polyhydric alcohol. Examples of the polycarboxylic acids include fumaric acid, maleic acid, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid, 3-isodecenyl-1,2,5,6-hexanetetracarboxylic acid, and succinic acid And carboxylic acids such as isooctylsuccinic acid and adipic acid, carboxylic acid anhydrides thereof, and lower alkyl esters of carboxylic acids.

On the other hand, polyhydric alcohols include, for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, neopentyl glycol, polyoxyethylene (2.2) -2,2'-bis (4- Hydroxyphenyl) propane, polyoxypropylene (2.2) -2,
2'-bis (4-hydroxyphenyl) propane, hydrogenated bisphenol A, glycerin, trimethylolpropane and the like are used. If necessary, monocarboxylic acids and monoalcohols can be added as a polyester raw material.

The ring and ball method of the above polyester resin (JIS K-22
07) is from 90 ° C to 110 ° C.
When SP exceeds this range, the molecular weight of the binder resin becomes too large, and the property of sharply dissolving due to the entanglement of the polymer chains is impaired, so that the image lacks transparency and only a dull color image with low saturation can be obtained. Absent. In particular, those having an SP exceeding 130 ° C. are not preferred. If the SP is less than 90 ° C., the molecular weight of the binder resin becomes too small, and the glass transition point is lowered, so that blocking of the toner is apt to occur and storage stability is deteriorated.

In the present invention, the metal salt of a benzylic acid derivative represented by the general formula (I), which is a charge control agent contained in the toner, is preferably a sodium salt or a potassium salt, and particularly preferably a potassium salt. The amount of the benzylic acid derivative metal salt is usually 0.1 to 100 parts by weight of the binder resin.
It is 5 parts by weight, preferably 0.5 to 3 parts by weight. If the amount is less than this range, the charging becomes non-uniform and toner tends to be scattered.If the amount is more than this range, uniform dispersion becomes difficult, and the toner is aggregated in the toner. Tend to be non-uniform.

In the present invention, the colorant contained in the toner includes C.I. I. Pigment Red 122 is used. In the present invention, the metal salt of the benzylic acid derivative and C.I. I. By using Pigment Red 122 in combination, it is possible to obtain a magenta developer that has good hue of an image and is less likely to fade after image formation.

C. I. Pigment Red 122 is used in an amount of usually 1 to 10 parts by weight, preferably 4 to 8 parts by weight, based on 100 parts by weight of the binder resin. If the amount is less than this range, the coloring tends to be inferior and a clear image tends not to be obtained. If the amount is more than this range, aggregation of the pigment tends to occur, and the transparency of the OHP tends to deteriorate. .

The toner used in the present invention is obtained by mixing and dispersing a charge control agent, a colorant, and, if necessary, various additives such as wax in the polyester resin.
The particles are preferably ground to about 30 μm.

As the carrier used in the present invention, known carriers can be used, and examples thereof include magnetic materials such as iron, ferrite, steel, magnetite, and nickel.

In the present invention, the coating material used for coating the carrier is a silicone resin or an acrylic resin.

When the coating material is a silicone resin, more preferably, after coating the silicone varnish on the carrier,
It is preferable to heat cure at a temperature of 80 ° C. or higher. The silicone varnish is a straight silicone resin, for example, KR-114, KR-220, KR-2
51 and KR-255 (both manufactured by Shin-Etsu Silicone Co., Ltd.). Further, a silicone resin modified with a urethane resin or an epoxy resin or the like can be used alone or as a mixture with the straight silicone, and used as the silicone resin in the present invention.

On the other hand, when the coating material is an acrylic resin, examples of monomers serving as a base of the resin include methacrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate and the like.
Further, a copolymer of the above acrylic monomer and a styrene monomer such as styrene, p-methylstyrene and pt-butylstyrene can also be used as the acrylic resin in the present invention.

In the case of the silicone resin, a conductive powder is dispersed in the resin. As the conductive powder, carbon black, conductive tin oxide, conductive titanium oxide and the like can be used. The amount of conductive powder used depends on the resin 1 to be coated.
The amount is usually 1 to 20 parts by weight, preferably 5 to 15 parts by weight based on 00 parts by weight. If the amount used is less than this range, the resistance of the coat carrier will increase, and it tends to be difficult to obtain appropriate chargeability.If the amount used is greater than this range, the conductive powder will be more easily detached than the coat resin, It tends to be mixed in the toner and deteriorate the hue.

In the present invention, in order to coat the carrier with the coating material, for example, a ferrite fluidized in a fluidized bed is sprayed with a silicone resin solution in which carbon black or the like is dispersed under heating, and then dried. Heat treatment may be performed according to the conditions.

The magenta developer of the present invention can be produced by mixing the toner and the coated carrier by a conventional method using a mixer, a V-type blender or the like.

[0028]

EXAMPLES The present invention will be described in more detail with reference to Synthesis Examples, Production Examples, Examples and Comparative Examples, but the present invention is not limited to these Examples and the like. The “parts” shown below indicate “parts by weight”.

Synthesis Example 1 149.1 parts of propylene glycol, 52.1 parts of ethylene glycol and 410.2 parts of dimethyl terephthalate were placed in a reaction vessel equipped with a stirrer, a reflux dewatering tube for cooling and removing reaction water, and a nitrogen blowing tube. At 220 ° C
When methanol was distilled off after completion of the methanol removal reaction, 55.3 parts of trimellitic anhydride was added and further reacted to obtain a softening point (SP) of 104.5 ° C. and a glass transition point (Tg) of 62. A polyester resin at 0.4 ° C. was obtained.

Synthesis Example 2 In a reactor similar to Synthesis Example 1, 350.0 parts of polyoxypropylene (2.2) -2,2 '-(4-hydroxyphenyl) propane, 116.0 parts of fumaric acid, 0.2 parts of hydroquinone monomethyl ether was charged and the temperature was gradually raised, followed by a dehydration condensation reaction at 210 ° C., and a softening point of 101.6.
A polyester resin having a Tg of 61.5 ° C was obtained.

Production Example 1 Ferrite (F-1530) 1, manufactured by Powdertech Co., Ltd.
000 parts was fluidized in a fluidized bed, and heated to 60 ° C., and 10 parts of a silicone resin (KR-251, Shin-Etsu Silicone Co., Ltd., KR-251) dissolved in 5% with toluene was mixed with carbon black (resin content). CAGRACK, MOGULL)
One part of the dispersion was sprayed, dried for 20 minutes, and then heat-treated at 200 ° C. for 30 minutes in an electric furnace to obtain a silicone resin-coated carrier.

Production Example 2 Ferrite (F-1530) 1, manufactured by Powdertech Co., Ltd.
000 parts were fluidized with a fluidized bed and heated to 60 ° C., and 10 parts of styrene-acrylic resin (NK-32, manufactured by Nippon Paint Co., Ltd.) dissolved in toluene at 5% (resin content).
Was sprayed and further dried for 20 minutes to obtain an acrylic resin-coated carrier.

Example 1 The following composition: 100.0 parts of the polyester resin of Synthesis Example 1 I. Pigment Red 122 5.0 parts Potassium salt of benzylic acid derivative 1.0 part Viscol 550P (manufactured by Sanyo Kasei Co., Ltd., 2.0 parts by weight of polypropylene) was mixed in a blender and melt-kneaded in a twin-screw extruder. After coarse pulverization with a cutter mill, the mixture was pulverized and classified with an air jet mill to 5 to 20 μm and an average particle diameter of 10 μm. To 100 parts of the fine particles, 0.4 part of hydrophobic silica R972 (manufactured by Nippon Aerosil Co., Ltd.) was mixed to prepare a toner. 40 parts of the toner and the silicone-coated carrier 960 of Production Example 1
Were mixed with a V-type blender to obtain a developer.

The developing property of this developer was evaluated using a commercially available color printer equipped with OPC (QMS Japan, Color Script Laser 1000). Initially, the charge amount was -19.3 μc / g, and the developer was clear and fogged. A high-density image having no image was obtained. Further, even after continuous printing of 10,000 sheets, the charge amount was -17.1 μc / g, and an image of good quality having no difference from the initial image was obtained. The image printed on the OHP sheet had good transparency, and the image projected by the OHP had a good magenta color.

Example 2 The following composition: 100.0 parts of polyester resin of Synthesis Example 2 potassium salt of benzylic acid derivative 1.0 part I. Pigment Red 122 5.0 parts Viscol 550P (manufactured by Sanyo Kasei Co., Ltd.) 2.0 parts was manufactured in the same manner as in Example 1. Next, 40.0 parts of the toner and 960 parts of the acrylic resin-coated carrier of Production Example 2 were mixed to prepare a developer.

Comparative Example 1 The following composition: Tufton NE1110 (manufactured by Kao Corporation, polyester resin SP130 ° C.) 100.0 parts Potassium salt of benzylic acid derivative 1.0 part I. Pigment Red 122 3.0 parts Viscol 550P (manufactured by Sanyo Chemical Industries, Ltd.) 2.0 parts was prepared in the same manner as in Example 1. Next, 40.0 parts of the toner and 960 parts of the silicone resin-coated carrier of Production Example 1 were mixed to produce a developer.

Comparative Example 2 The following composition: polyester resin of Synthesis Example 1 100.0 parts Potassium salt of benzylic acid derivative 1.0 part I. Pigment Red 57: 1 3.0 parts Viscol 550P (manufactured by Sanyo Kasei Co., Ltd.) 2.0 parts was manufactured in the same manner as in Example 1. Next, 40.0 parts of the toner and 960 parts of the silicone resin-coated carrier of Production Example 1 were mixed to produce a developer.

Comparative Example 3 The following composition: polyester resin of Synthesis Example 1 100.0 parts Potassium salt of benzylic acid derivative 1.0 part I. Pigment Red 48: 3 3.0 parts Viscol 550P (manufactured by Sanyo Chemical Industries, Ltd.) 2.0 parts of a toner was produced in the same manner as in Example 1. Next, 40.0 parts of the toner and 960 parts of the silicone resin-coated carrier of Production Example 1 were mixed to produce a developer.

Comparative Example 4 The following composition: polyester resin of Synthesis Example 2 100.0 parts Potassium salt of benzylic acid derivative 1.0 part I. Pigment Red 122 3.0 parts Viscol 550P (manufactured by Sanyo Chemical Industries, Ltd.) 2.0 parts was prepared in the same manner as in Example 1. Next, 40.0 parts of the toner and 960 parts of an uncoated ferrite carrier (F-1530, manufactured by Powder Tech) were mixed,
A developer was manufactured.

Comparative Example 5 The following composition: 100.0 parts of polyester resin of Synthesis Example 1 I. Pigment Red 122 3.0 parts Viscol 550P (manufactured by Sanyo Chemical Industries, Ltd.) 2.0 parts was prepared in the same manner as in Example 1. Next, 40.0 parts of the toner and 960 parts of the silicone resin-coated carrier of Production Example 1 were mixed to produce a developer.

Comparative Example 6 The following composition: polyester resin of Synthesis Example 1 100.0 parts Bontron S34 (manufactured by Orient, charge control agent) 2.0 parts I. Pigment Red 122 3.0 parts Viscol 550P (manufactured by Sanyo Chemical Industries, Ltd.) 2.0 parts was prepared in the same manner as in Example 1. Next, 40.0 parts of the toner and 960 parts of the acrylic resin-coated carrier of Production Example 2 were mixed to prepare a developer.

The developability of each developer obtained in Example 2 and Comparative Examples 1 to 6 was evaluated in the same manner as in Example 1. Table 1 shows the results together with the results of Example 1.

[0043]

[Table 1]

* 1: Measurement by blow-off method (μc /
g) * 2: Measurement by Macbeth densitometer RD-914 * 3: Evaluation based on area ratio of background fogging toner per unit area of unimaged area ○: Less than 0.1% ×: 0.1% or more * 4: Magenta solid image Print on an OHP sheet, project it with a projector, and visually evaluate ○: good color development ×: poor color development * 5: visually evaluate magenta solid image ○: good hue ×: poor hue * 6: weather solid image Meter (manufactured by Suga Test Instruments Co., Ltd.
After light irradiation for 8 hours with a WEL-SUN-DC-B type, the hue is measured with a colorimeter (SZ- # 80, manufactured by Nippon Denshoku Co., Ltd.) and evaluated based on the color difference from before irradiation.

As is evident from the results shown in Table 1, the products of the present invention (Examples 1 and 2) both show a good charge amount and are clear and free of fog both at the initial stage and after repeated use. Moreover, a high-density image was given. Furthermore, the image printed on the OHP sheet shows good transparency, and comparative products using other pigments (Comparative Examples 2-3)
The image had better hue and fading resistance as compared with. On the other hand, the comparative product 1 using a resin having a high softening point has low transparency, the comparative product 4 using an uncoated carrier has poor charge stability, and the comparative product 5 using no charge control agent has fog. Comparative Example 6 using a charge control agent different from that of the present invention was inferior in transparency and image hue.

[0046]

The magenta developer of the present invention has excellent image density and low fog, and the image developed to OHP transparency has good transparency, the light transmission image shows vivid coloration, and is stable for a long time. It shows the improved chargeability. Further, the hue of the image is good, and fading after image formation hardly occurs.

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁷ identification code FI G03G 9/10 361 (56) References JP-A-5-257324 (JP, A) JP-A-6-250442 (JP, A) JP-A-5-224465 (JP, A) JP-A-3-112990 (JP, A) JP-A-5-72812 (JP, A) JP-A-3-221968 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03G 9/09 G03G 9/097 G03G 9/113 CA (STN)

Claims (3)

(57) [Claims] 1. A magenta developer containing a colorant comprising a chromatic dye or a pigment, a toner containing a binder resin and a charge control agent, and a coated carrier, wherein the colorant is
C. I. Pigment Red 122, wherein the binder resin is a polyester resin having a softening point of 90 to 110 ° C. according to a ring and ball method, and the charge control agent is represented by the following general formula (I): (Wherein, M represents lithium, sodium or potassium), a metal salt of a benzylic acid derivative represented by the formula: wherein the carrier coating material is a silicone resin or an acrylic resin obtained by dispersing a conductive powder. A magenta developer, characterized in that: 2. C. I. The magenta developer according to claim 1, wherein the amount of Pigment Red 122 is 1 to 10 parts by weight based on 100 parts by weight of the binder resin. 3. The use amount of a metal salt of a benzylic acid derivative is as follows:
3. The magenta developer according to claim 1, wherein the amount is 0.5 to 5 parts by weight based on 100 parts by weight of the binder resin.