JP2002304021A - Dry electrophotographic toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dry electrophotographic toner being free of aggregation in a toner bottle and a developing machine and giving an image of good quality. SOLUTION: In the dry electrophotographic toner consisting essentially of a colorant and a binder resin, the binder resin is a copolymer resin comprising (I) a polyol resin part having a polyoxyalkylene moiety in the principal chain obtained by reacting (a) an epoxy resin with (b) a dihydric phenol and (c) an alkylene oxide adduct of a dihydric phenol or its glycidyl ether and (II) a polyester resin part obtained by reacting at least an alkylene oxide adduct of a dihydric phenol or its glycidyl ether and a polycarboxylic acid, the weight ratio between the epoxy resin in the polyol resin part and the polyester resin part is (95:5) to (60:40), the epoxy resin comprises two or more bisphenol type epoxy resins different from each other in number average molecular weight and the acid value of the copolymer resin is <=5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dry electrophotographic toner, and more particularly, to a toner suitable for a one-component developing system or a two-component developing system full-color image forming apparatus.

[0002]

2. Description of the Related Art In dry electrophotography, an electrostatic latent image is formed on a photoreceptor, developed with dry toner, the toner image is transferred onto copy paper, and then heat-fixed (usually using a heat roller). I have a copy. In particular, in order to obtain a full-color image, image gloss and good color development are required. Therefore, polyester resins as disclosed in JP-A-61-7844 and polyol resins as disclosed in JP-A-7-77832 are often used. Has been used.

[0003] In the case of a toner using a polyester resin, agglomerates are easily generated in a toner bottle or a developing device, and a problem that an image in a portion where the agglomerates are present is apt to come off white.
Further, if the obtained image is kept in contact with a PVC mat or the like, problems such as sticking of the image and sticking of the image are likely to occur. Further, when the acid value is high, the charging potential is increased, but environmental fluctuations are worsened. In the case of a toner using a polyol resin, since the chargeability of the polyol resin is low, when an image is formed by a one-component development method, problems such as generation of a background stain image and low image density occur. Also, even in the case of the two-component developing method, in an image forming apparatus using a small developing device, the friction effect due to the weight of the developer itself during stirring becomes small because the amount of the developer is small, and as a result, the charge amount is low. This causes problems such as generation of a background image and low image density. In particular, since the color developer has a higher toner concentration than the mono-black developer, the above-mentioned problem becomes remarkable when a two-component developing type full-color image forming apparatus using a small developing device is used. .

[0004]

An object of the present invention is to provide, for example, an image forming apparatus of a one-component developing system or a two-component developing system using a small developing device having a small amount of developer.
An object of the present invention is to provide a toner having the following characteristics. First, it is to provide a toner capable of obtaining a clear image having a sufficient image density without a background image. Second, to provide a toner capable of obtaining an image having proper and uniform gloss. Third, to provide a toner capable of obtaining an image free from image blurring, particularly in a halftone portion. Fourth, to provide a toner in which no aggregates are generated in a toner bottle or a developing device, and a phenomenon in which an image of a portion where the aggregates are present is not whitened is generated. Fifth, to provide a toner that does not adhere to a PVC mat or the like. Sixth, to provide a toner with better productivity. Here, good productivity means that there is no possibility that a target product cannot be obtained, for example, a side reaction occurs during production. Furthermore, it means that sensitization does not affect the health and safety of workers.

[0005]

The above object is achieved by the following (1).
(8). (1) In a dry electrophotographic toner containing at least a colorant and a binder resin as main components, the binder resin includes: I) (a) an epoxy resin, (b) a dihydric phenol,
(C) an alkylene oxide adduct of a dihydric phenol or a polyol resin part having a polyoxyalkylene moiety in the main chain obtained by reaction with a glycidyl ether thereof; and II) an alkylene oxide adduct of at least a dihydric phenol or an adduct thereof. A copolymer resin comprising a polyester resin part obtained by the reaction of glycidyl ether and a polyvalent carboxylic acid, wherein the weight ratio of the epoxy resin to the polyester resin part in the polyol resin part is from 95/5 to 60 / 40, that the epoxy resin of the polyol resin part is at least two or more bisphenol type epoxy resins having different number average molecular weights, and that the acid value of the copolymer resin is 5 or less. Characteristic dry electrophotographic toner.

(2) A dry electrophotographic toner according to the above (1), wherein the epoxy equivalent of the resin is 20,000 or more.

(3) The toner for dry electrophotography according to the above (1) or (2), wherein the resin has an acid value of 1 or less.

(4) The toner for dry electrophotography according to any one of (1) to (3) above, wherein the polycarboxylic acid in the polyester resin portion is a dicarboxylic acid.

(5) In the toner according to any one of the above (1) to (4), the epoxy resin in the polyol resin part comprises a low molecular weight component having a number average molecular weight of 360 to 2,000, and a number average molecular weight. Is a high molecular weight component having a molecular weight of 3,000 to 10,000.

(6) The toner according to any one of (1) to (4) above, wherein the polyester resin portion has a number average molecular weight of 500 to 2,000.

(7) In the toner according to any one of the above (1) to (6), the copolymer resin comprises (a) an epoxy resin, (b) a dihydric phenol, and (c) a dihydric phenol. (E) a polyester resin obtained by reacting an alkylene oxide adduct of phenol or its glycidyl ether with (d) an alkylene oxide adduct of dihydric phenol or its glycidyl ether and a polycarboxylic acid, and (e) a monohydric phenol or A dry electrophotographic toner obtained by reaction with a monocarboxylic acid.

(8) A full-color image forming apparatus having a toner container containing the dry electrophotographic toner according to any one of the above (1) to (7).

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. The present invention provides a polyoxyalkylene moiety in the main chain synthesized by reacting (a) an epoxy resin, (b) a dihydric phenol, and (c) an alkylene oxide adduct of a dihydric phenol or a glycidyl ether thereof. Using, as a binder resin, a copolymer resin consisting of a polyol resin part having the following formula and a polyester resin part synthesized by reacting at least an alkylene oxide adduct of dihydric phenol or its glycidyl ether with a polycarboxylic acid. Thus, while preventing the phenomenon in which an image comes out white and adhesion of vinyl chloride mat, it is possible to prevent a background image and to maintain the image density when using a one-component developing system or a two-component developing system using a small amount of developer.

Here, the weight ratio of the epoxy resin, which is a constituent resin of the polyol resin portion, to the polyester resin portion is as follows:
It needs to be 95/5 to 60/40. 60
If it is smaller than / 40, environmental fluctuations are worsened, which is not only undesirable, and phenomena such as adhesion to a PVC mat or the like are observed. If the ratio is larger than 95/5, there is a problem that the image quality cannot be improved in a one-component developing system or a two-component developing system full-color image forming apparatus using a small developing device with a small amount of developer.

The polyol resin in the present invention refers to a polyether polyol resin having an epoxy skeleton but having no terminal epoxy. In addition, by having a polyoxyalkylene portion in the main chain, good gloss can be obtained.

In the synthesis of the resin of the present invention, if the polyol portion is constituted by using at least two kinds of bisphenol A type epoxy resins having different number average molecular weights, an appropriate molecular weight distribution can be obtained and a clear color image can be obtained. Can be obtained. In this case, the number average molecular weight of the low molecular weight component is preferably from 360 to 2,000, and the number average molecular weight of the high molecular weight component is preferably from 3,000 to 10,000.
The molecular weight distribution of the epoxy resin is expressed by the ratio of the number average molecular weight to the volume average molecular weight. In the case of a glossy color toner, it is preferably 3 to 8, and the low molecular weight component epoxy resin and the high molecular weight epoxy resin used in the synthesis are preferably used. Control by ratio.

On the other hand, the polyester resin portion can be synthesized by, for example, a condensation reaction between an alkylene oxide adduct of bisphenol A and a polycarboxylic acid, and preferably has a number average molecular weight of 500 to 2,000.

The copolymer resin of the present invention comprises (a) an epoxy resin, (b) a dihydric phenol, (c) an alkylene oxide adduct of a dihydric phenol or a glycidyl ether thereof, and (d) a dihydric phenol. A polyester resin obtained by the reaction of an alkylene oxide adduct or a glycidyl ether thereof with a polycarboxylic acid,
(E) It can be obtained by reaction with a monohydric phenol or a monocarboxylic acid. The reaction is aromatic hydrocarbons, ketones,
The reaction can be carried out in an appropriate solvent such as ether, ester or alcohol, and a solvent having a relatively high boiling point such as xylene can be particularly preferably used. Also, the above reaction is lithium chloride,
The reaction can be performed in the presence of a catalyst such as an amine catalyst. The polymerization reaction is usually performed at a temperature of 50 to 200 ° C for 1 to 24 hours. The copolymer resin of the present invention also comprises a polyol resin obtained by reacting (a) an epoxy resin, (b) a dihydric phenol, and (c) an alkylene oxide adduct of a dihydric phenol or its glycidyl ether. And a polyester resin obtained by a reaction of an alkylene oxide adduct of dihydric phenol or a glycidyl ether thereof with a polycarboxylic acid and a dihydric phenol, a monohydric phenol or a monocarboxylic acid. The reaction conditions are the same as described above.

The copolymer resin of the present invention has no terminal epoxy group and has an epoxy equivalent of 20,000.
The use of a value of 0 or more is excellent in sensitization and stability during production. The terminal epoxy group may be etherified or esterified by reacting dihydric phenol, monohydric phenol or monocarboxylic acid.

The softening point of the copolymer resin of the present invention is as follows:
The range of 100-130 degreeC is preferable. If the temperature is lower than 100 ° C., agglomerates are likely to be generated in the toner bottle or the developing device, and the phenomenon that the image of the agglomerates is whitened out at the time of development and transfer tends to occur. Conversely, if the temperature exceeds 130 ° C., there is a tendency that a problem that a sufficient fixing property is hardly obtained.

Further, the acid value of the copolymer resin of the present invention is 5
Is preferably 1 or less, and more preferably 1 or less. If the acid value is high, stability tends to be lacking, such as a decrease in charge amount at high humidity.

The compounds constituting the polyol resin part of the resin of the present invention include the following materials. Examples of the epoxy resin (a) used in the production of the polyol resin part include those obtained by subjecting bisphenol A or bisphenol to an epichlorohydrin resin by a condensation reaction.

(B) As the dihydric phenol, for example,
Bisphenols such as bisphenol A and bisphenol F are mentioned.

The (c) alkylene oxide adduct of a dihydric phenol used in the synthesis of the polyol resin portion includes, for example, an alkylene oxide such as ethylene oxide, propylene oxide, butylene oxide and a mixture thereof, and bisphenol A And reaction products with bisphenols such as bisphenol F. The obtained adduct may be further glycidyl-etherified with epichlorohydrin or β-methylepichlorohydrin.

Particularly, a diglycidyl ether of an alkylene oxide adduct of bisphenol A represented by the following general formula (1) is preferred.

Embedded image [Wherein, R _{-CH 2 -CH 2 -, - CH} 2 -CH (C
_{H 3) -, - CH 2} -CH 2 -CH 2 - is. n and m are each 1 or more, and n + m = 2 to 8. If n + m in the above formula (1) exceeds 8, there is a possibility that storage stability may be deteriorated.

The ratio of each of (a), (b) and (c) is 25
To 70, 10 to 40 and 15 to 40 are preferred.

Examples of the monohydric phenol reacted with the epoxy group include phenol, cresol, isopropylphenol, amylphenol, nonylphenol, dodecylphenol, xylenol and p-phenol.
-Cumylphenol and the like.

Examples of the monocarboxylic acids include aromatic carboxylic acids such as benzoic acid and aliphatic carboxylic acids such as stearic acid.

On the other hand, the compounds constituting the polyester resin portion of the resin of the present invention include the following materials.

2 used for production of polyester resin part
Examples of the alkylene oxide adduct of a divalent phenol or its glycidyl ether include reaction products of an alkylene oxide such as ethylene oxide, propylene oxide, butylene oxide and a mixture thereof with a bisphenol such as bisphenol A or bisphenol F.

The following are examples of polyvalent carboxylic acids used for producing the polyester resin part.
Specific examples of divalent carboxylic acids include aliphatic dicarboxylic acids and derivatives thereof (maleic acid, fumaric acid, succinic acid, adipic acid, sebacic acid, malonic acid, azelaic acid, mesaconic acid, citraconic acid, glutaconic acid, octylsuccinic acid) Acid, decylsuccinic acid, dodecylsuccinic acid, tetradecylsuccinic acid, hexadecylsuccinic acid, octadecylsuccinic acid, isooctadecylsuccinic acid, hexenylsuccinic acid, octenylsuccinic acid, decenylsuccinic acid, dodecenylsuccinic acid, tetrapropenylsuccinic acid, tetradecenylsuccinic acid Succinic acid, hexadecenyl succinic acid, isooctadecenyl succinic acid, octadecenyl succinic acid, nonenyl succinic acid, etc.), alicyclic dicarboxylic acids (cyclohexane dicarboxylic acid, methyl medic acid, etc.), aromatic dicarboxylic acids ( Phthalic acid, i Phthalic acid, terephthalic acid, toluene dicarboxylic acid, naphthalene and di-carboxylic acid) as well as these divalent anhydrides of carboxylic acids or lower alkyl (methyl, butyl, etc.) ester.

Examples of trivalent carboxylic acids include trimellitic acid, pyromellitic acid, 1,2,4-cyclohexanetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,
There are 5-hexanetricarboxylic acid, 1,2,7,8-octanetetracarboxylic acid and their anhydrides.

These can be used alone or as a mixture. Such a polyfunctional group monomer has an effect of increasing the Tg of the resin, and has an effect of imparting cohesiveness to the resin and increasing the offset resistance.

The Tg of the obtained resin is preferably from 50 ° C. to 75 ° C., more preferably from 55 ° C. to 70 ° C. If the Tg is low, aggregates are likely to be generated in the toner bottle or the developing device, and the aggregates are likely to be developed and a phenomenon in which the image of the aggregate portion is whitened during transfer is likely to occur.
Conversely, if the Tg is high, there tends to be a problem that it is difficult to obtain sufficient image gloss.

Next, other materials used in the dry toner of the present invention will be described. In the toner of the present invention, a so-called release agent that imparts release properties to the toner may be used. The softening point of the release agent used is preferably from 70 to 100C. If the softening point is lower than 70 ° C., there is a problem in storage stability. Conversely, if the softening point is higher than 100 ° C., not only the fixing becomes insufficient, but also the color image becomes poor such as low gloss. Because it is easy.

Specific release agents include synthetic waxes such as low molecular weight polyethylene, polypropylene and copolymers thereof; vegetable waxes such as candelilla wax, carnauba wax, rice wax, wood wax, jojoba wax; Animal waxes such as beeswax, lanolin and whale wax; mineral waxes such as montan wax and ozokerite; oil waxes such as hardened castor oil, hydroxystearic acid, fatty acid amides and phenol fatty acid esters.

From the viewpoint of chemical structure, hydrocarbon waxes, ester waxes, amide waxes and the like are known from the viewpoint of the chemical structure. It is preferable to evaluate the fixing temperature range.

The amount of the release agent is preferably 1 to 6% by weight based on the whole toner. If the amount is more than 6% by weight, problems such as storage stability and the like, and the image surface is likely to be rough and glossiness is low. If the amount is less than 1% by weight, the color image tends to be poor, for example, the image surface is easily roughened and the gloss is low.

As the coloring agent, all known dyes and pigments can be used. For example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (1
0G, 5G, G), cadmium yellow, yellow iron oxide, ocher, graphite, titanium yellow, polyazo yellow, oil yellow, Hansa yellow (GR, A, RN, R), pigment yellow L, benzidine yellow ( G, G
R), Permanent Yellow (NCG), Vulcan Fast Yellow (5G, R), Tartrazine Lake, Quinoline Yellow Lake, Anthrazan Yellow BGL, Isoindolinone Yellow, Bengala, Lead Tan, Lead Zhu, Cadmium Red, Cad Muum Mercury Red, Antimony Vermilion, Permanent Red 4R, Para Red, Phisaed Red, Parachlor Ortho Nitroaniline Red, Risor Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmine Min BS, Permanent Red (F2R, F4R, FRL, FRL)
L, F4RH), Fast Scarlet VD, Belcan Fast Rubin B, Brilliant Scarlet G, Lisor Rubin GX, Permanent Red F5R, Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Toluidine Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B , Bon Maroon Light, Bon Maroon Media, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thioindigo Red B, Thioindigo Maroon, Oil Red, Quinacridone Red, Pyrazolone Red, Polyazo Red, Chrome Vermilion, Benzidine Orange , Perinone orange, oil orange,
Cobalt blue, Cerulean blue, alkali blue lake, peacock blue lake, Victoria blue lake, metal-free phthalocyanine blue, phthalocyanine blue, fast sky blue, indanthrene blue (R
S, BC), indigo, ultramarine, navy blue, anthraquinone blue, fast violet B, methyl violet lake, cobalt violet, manganese violet, dioxane violet, anthraquinone violet, chrome green, zinc green, chromium oxide, pyridian, emerald green, pigment green B, naphthol green B, green gold, acid green lake, malachite green lake, phthalocyanine green, anthraquinone green, titanium oxide, zinc white, lithobone and mixtures thereof.

The amount of the colorant used is generally the amount of the binder resin 1
It is 0.1 to 50 parts by weight with respect to 00 parts by weight.

The toner of the present invention may contain a charge controlling agent as required. All known charge control agents can be used, for example, nigrosine dyes, triphenylmethane dyes, chromium-containing complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines,
Quaternary ammonium salts (including fluorinated quaternary ammonium salts), alkylamides, phosphorus alone or compounds, tungsten alone or compounds, fluorine-based activators, salicylic acid metal salts, and metal salts of salicylic acid derivatives.

Other additives include, for example, silica fine particles, metal salts of fatty acids (such as zinc stearate and aluminum stearate), metal oxides (such as titanium oxide, aluminum oxide, tin oxide and antimony oxide), and fluoropolymers. May be. In particular, hydrophobic silica, titania, and alumina fine particles are preferable.

As the silica fine particles, HDK H20
00, HDK H 2000/4, HDK H 205
0EP, HDK H 1303VP (all manufactured by Clariant), R972, R974, RX200, RY20
0, R202, R805, and R812 (all manufactured by Nippon Aerosil Co., Ltd.).

As the titania fine particles, P-25
(Nippon Aerosil Co., Ltd.), STT-30, STT-65
CS (above, manufactured by Titanium Industry Co., Ltd.), TAF-140 (manufactured by Fuji Titanium Industry Co., Ltd.), MT-150W, MT-500
B, MT-600B (all manufactured by Teika) and the like.

In particular, as the titanium oxide fine particles subjected to the hydrophobic treatment, an anatase type or rutile type crystalline or non-crystalline type can be used. T-805 (manufactured by Nippon Aerosil Co., Ltd.) or rutile type can be used. MT-100S, MT
-100T, MT150A, MT150AFM (above,
Teica), STT-30A, STT-65S-S
(Titanium Industry Co., Ltd.), TAF-500T, TAF
-1500T (above, manufactured by Fuji Titanium Industry Co., Ltd.), MT-1
00S, MT-100T (all manufactured by Teika), IT-
S (manufactured by Ishihara Sangyo).

In order to obtain hydrophobized silica fine particles, titania fine particles and alumina fine particles, hydrophilic fine particles are treated with a silane coupling agent such as methyltrimethoxysilane, methyltriethoxysilane or octyltrimethoxysilane. Can be obtained. In addition, fatty acid metal salts (zinc stearate, aluminum stearate, etc.), metal oxides (alumina, tin oxide, antimony oxide, etc.), fluoropolymers and the like may be added as additives.

The toner of the present invention composed of the above materials may be used as a two-component developer together with the following carrier, or may be used alone as a one-component developer.

When used as a two-component developer, the carrier used is the same as the conventional one, such as iron powder, ferrite, and glass beads. These carriers may be coated with a resin. The resin used in this case may be a known resin, but examples include acrylic resin, polyfluorocarbon, polyvinyl chloride, polyvinylidene chloride, phenol resin, polyvinyl acetal, and silicone resin.

In any case, the mixing ratio of the toner and the carrier is generally 100 parts by weight of the carrier and 0.1% of the toner.
About 5 to 6.0 parts by weight is appropriate.

The following method is used to measure the softening point and Tg of the resin of the present invention. First, as a device for measuring the softening point, a fully automatic dropping device FP5 / FP of Metra Co., Ltd.
The measurement is performed by the following procedure using No. 53. 1) After the pulverized sample is placed in a melting pot and left for 20 minutes, the sample is poured up to the edge of a sample cup (droplet diameter: 6.35 mm), cooled to room temperature, and set in a cartridge. 2) Predetermined heating rate (1 ° C / min) measurement start temperature (15 ° C of expected softening temperature) to FP-5 control unit
Set below). 3) Attach the cartridge to the FP-53 heating furnace, leave it for 30 seconds, and then push down the start lever to start measurement (the subsequent measurements are performed automatically). 4) When the measurement is completed, remove the cartridge. 5) The softening point (° C.) is calculated as follows. The value of the result display panel A of FP-5 + correction value (Here, if the above correction value is added to the obtained result, it corresponds to the result of the Duran mercury method. Also, the value of the result display panel A and the measurement start Difference in temperature (values of panels B and C) is 15
If not, repeat the test. )

Next, as a device for measuring Tg, DSC-200 manufactured by Seiko Denshi Co., Ltd. is used, and the Tg is measured according to the following procedure. 1) Crush the sample, weigh 10 ± 1 mg in an aluminum sample container, and crimp the aluminum lid from above. 2) Glass transition temperature (T
g) is measured.

(Analysis Conditions) The sample was heated from room temperature to a heating rate of 2
After heating to 150 ° C at 0 ° C / min,
The sample was cooled to 0 ° C. at a cooling rate of 50 ° C./min and left for 10 min.
min), the sample is heated again to 150 ° C. at a heating rate of 20 ° C./min, and the DSC measurement is performed. Tg is calculated using analysis software [Tg
Job], and read the peak rise temperature. The epoxy equivalent was determined by an indicator titration method described in 4.2 of JIS K7236.

[0053]

The present invention will be described below with reference to examples. All parts are parts by weight. These embodiments are merely examples of the present invention, and the present invention is not limited to the embodiments.

(Example 1) (Synthesis example of resin) A low molecular weight bisphenol A was placed in a separable flask equipped with a stirrer, thermometer, N ₂ inlet, and condenser.
/ Epichlorohydrin type epoxy resin (E made by Mitsui Chemicals, Inc.)
POMIK R-140P number average molecular weight: about 360) 3
00g, high molecular weight bisphenol A / epichlorohydrin type epoxy resin (EPOMIK R- manufactured by Mitsui Chemicals, Inc.)
309 number average molecular weight: about 2900) 150 g, diglycidylation of bisphenol A type propylene oxide adduct (n + m in the above general formula (1): about 2.1) 2
30 g, bisphenol A 240 g, p-cumylphenol 90 g, 50 g of low molecular weight polyester resin (condensate of bisphenol A type propylene oxide adduct and phthalic anhydride, number average molecular weight about 1500), xylene 20
0 g was added. The temperature was raised to 70 to 100 ° C. in a N ₂ atmosphere, 0.183 g of lithium chloride was added, the temperature was further raised to 160 ° C., xylene was distilled off under reduced pressure, and polymerization was carried out at a reaction temperature of 180 ° C. for 6 to 9 hours. Thus, resin 1 was obtained. Physical properties of this resin were as follows: Mn: 4200, Mw / Mn: 6.0, Tg:
60 ° C., softening point 105 ° C. Acid value: 0.5, epoxy equivalent:
It was 20,000 or more.

Yellow toner prescription: Resin 1 100 parts Carnauba wax (ester wax, melting point: about 82 ° C.) 3 parts Yellow pigment (Toler Yellow HG manufactured by Clariant) 6 parts Orient Chemical Industries E-84 2 parts

Magenta toner formulation: Resin 1 100 parts Carnauba wax 3 parts Red pigment (Rionogen Magenta R manufactured by Toyo Ink Mfg. Co., Ltd.) 5 parts Orient Chemical Industries E-84 2 parts

Cyan toner formulation: Resin 1 100 parts Carnauba wax 3 parts Blue pigment (Lionol FG-7351 manufactured by Toyo Ink Mfg. Co., Ltd.) 4 parts E-84 manufactured by Orient Chemical Industries 2 parts

Black toner formulation: 100 parts of resin 1 3 parts of carnauba wax 3 parts of black pigment (carbon black; # 44 manufactured by Mitsubishi Chemical Corporation) 6 parts 2 parts of E-84 manufactured by Orient Chemical Industries

The mixture of the above materials is melt-kneaded by a hot roll mill, cooled, coarsely ground by a hammer mill, and finely ground by an air jet mill to classify the obtained fine powder to obtain a toner having an average particle diameter of about 7 μm. Had made. Next, the obtained toner 100
Parts, hydrophobic silica HDK2000H as an external additive
(Manufactured by Clariant Japan) 0.7 part was mixed, put into an experimental machine having a developing section shown in FIG. 1 and a fixing section of a PFA-coated silicon roller of φ30 (set temperature: 160 ° C.) at a process speed of 75 mm / sec When printing was performed continuously on 99 sheets of A4 size, and the images were evaluated, no change was found in the 99 sheets, and a good image was obtained. Also, yellow,
The average glossiness of the monochromatic solid images of magenta, cyan, and black was 18%. Printing was performed in an environment of 30 ° C. and 80% RH, but no particular image change was observed. yellow,
The monochromatic images of magenta, cyan, and black were sandwiched between PVC mats and left at 50 ° C. for 8 hours while being pressed with a 1 kg load, but no adhesion or the like occurred. The gloss was measured using a gloss meter (VG-1D) (manufactured by Nippon Denshoku Co., Ltd.).
The switching SW was set to S, and after the standard setting, the image was placed on the sample table and measurement was performed.

Example 2 In the same manner as in Example 1, a toner having an average particle size of about 7 μm was prepared from a mixture of the following color toner formulations. The resin 2 was synthesized in the same manner as in the above resin synthesis example except that the amount of the resin 2 was changed. Detailed formulations and physical properties are shown in Table 1.

Yellow toner formulation: Resin 2 100 parts Yellow pigment (Toler Yellow HG, Clariant) 6 parts Orient Chemical Industries E-84 2 parts

Magenta toner formulation: Resin 2 100 parts Red pigment (Toyo Ink Mfg. Co., Ltd. Rionogen Magenta R) 5 parts Orient Chemical Industries E-84 2 parts

Cyan toner formula: Resin 2 100 parts Blue pigment (Toyo Ink Mfg. Co., Ltd. Lionol Blue FG-7351) 4 parts Orient Chemical Industries E-84 2 parts

Black toner prescription: Resin 2 100 parts Black pigment (carbon black; # 44 manufactured by Mitsubishi Chemical Corporation) 6 parts Orient Chemical Industries E-84 2 parts

Next, with respect to 100 parts of the obtained toner, hydrophobic silica R972 (manufactured by Nippon Aerosil Co., Ltd.) as an external additive.
0.5 part and 0.3 part of hydrophobic titania STT-30A (manufactured by Titanium Industry Co., Ltd.) were mixed. Next, 5 parts of each color toner was mixed with 95 parts of a carrier obtained by coating a silicon resin on a spherical ferrite having an average diameter of 50 μm to prepare a two-component developer of each color. These four color developers were set in a commercially available color electrophotographic copying machine (PRETER550 manufactured by Ricoh Co., Ltd.), and 99 continuous images were taken.

When the obtained images were evaluated, there were no image changes in 99 sheets, and good images were obtained. Also,
The average glossiness of the monochromatic solid images of yellow, magenta, cyan, and black was 17%. 30 ° C 80% RH
Printing was performed in the environment described above, but no particular image change was observed.
A single-color image of yellow, magenta, cyan, and black is sandwiched between PVC mats and pressed at 1 kg load at 50 ° C. 8
After leaving for a while, no adhesion or the like occurred.

Example 3 Resin 3 was synthesized by changing phthalic anhydride in the synthesis example of the resin shown in Example 1 to trimellitic acid. Detailed formulations and physical properties are shown in Table 1. continue,
Yellow, magenta, cyan and black toners (average particle size: about 7 μm) were prepared in the same manner as in Example 1 except that resin 3 was used instead of resin 1. Next, R972 (manufactured by Nippon Aerosil Co., Ltd.) was used for 100 parts of the obtained toner.
0.5 part and 0.3 part of STT-30A (manufactured by Titanium Industry Co., Ltd.) were mixed. Next, 3 parts of each toner was mixed with 97 parts of a carrier obtained by coating a silicon resin on a spherical ferrite having an average diameter of 50 μm to prepare a two-component developer. These developers were used in a commercially available electrophotographic copying machine (image MF manufactured by Ricoh Co., Ltd.).
2700) and 99 images were taken continuously.

When the obtained image was evaluated, a good image was obtained without any image change in 99 sheets. Also,
Printing was performed in an environment of 30 ° C. and 80% RH, but no particular image change was observed. Monochrome image sandwiched between PVC mats, 1k
The mixture was allowed to stand at 50 ° C. for 8 hours while being pressed with a g load, but no adhesion or the like occurred.

Example 4 The weight ratio of the epoxy resin to the polyester resin in the polyol resin part of Example 2 was 6
Preparation and evaluation of the toner were performed in the same manner as in Example 2 except that the ratio was changed to 0/40.

Example 5 Preparation of a toner in the same manner as in Example 2 except that the reaction temperature and time of the polymerization reaction in Example 2 were changed to increase the acid value of the obtained copolymer resin to 4. And evaluations.

Comparative Example 1 The weight ratio of the epoxy resin to the polyester resin in the polyol resin portion of Example 2 was 1
A toner was prepared and evaluated in the same manner as in Example 2 except that the ratio was changed to 00/0 (that is, the polyester resin was not used).

Comparative Example 2 The weight ratio of the epoxy resin to the polyester resin in the polyol resin part of Example 2 was 5
Preparation and evaluation of the toner were carried out in the same manner as in Example 2 except that the ratio was changed to 0/50.

Comparative Example 3 Preparation of a toner in the same manner as in Example 2 except that the reaction temperature and time of the polymerization reaction in Example 2 were changed to increase the acid value of the obtained copolymer resin to 8. And evaluations.

Comparative Example 4 A high molecular weight bisphenol A / epichlorohydrin type epoxy resin (EPOMIK R-309 manufactured by Mitsui Chemicals, Inc.) was used as the epoxy resin of Example 1.
A toner was prepared and evaluated in the same manner as in Example 1 except that (number average molecular weight: about 2900) was used alone.

Comparative Example 5 A low-molecular bisphenol A / epichlorohydrin type epoxy resin (EPOMIK R-140P, number average molecular weight: about 360, manufactured by Mitsui Chemicals, Inc.) was used alone as the epoxy resin of Example 1.
Preparation and evaluation of the toner were carried out in the same manner as described above. Table 1 shows the formulations and physical properties of Examples 1 to 5 and Comparative Examples 1 to 5,
The experimental results are shown in Table 2.

[0076]

[Table 1]

[0077]

[Table 2]

(Evaluation Items) 1. Background fogging: Evaluation of background soiling during continuous copying 2. Image blur: evaluate uniformity of halftone portion 3. Aggregate: Evaluate the degree of aggregation after storing the toner at 50 ° C. for 48 hours. 4. White spots: Evaluate whether solid areas are white. PVC adhesion: Evaluate the fusing property after leaving the image at 50 ° C. for 8 hours under a constant pressurized condition 6. Evaluate the change in image density in an environment of 30 ° C./80%

(Evaluation rank) ：: No problem at all △: No problem Δ: Some problem but acceptable level ：: Some problem unacceptable ×: Very problem

[0080]

According to the dry electrophotographic toner of the present invention, no agglomerate is generated in the toner bottle or the developing device for a long period of time, and the phenomenon that the image of the portion where the agglomerate exists is not whitened does not occur. By using this toner,
It is possible to obtain a clear image without background fog and without image blurring in a halftone portion or white voids due to toner aggregates. Further, a toner in which the obtained copied image does not adhere to a PVC mat or the like could be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a one-component developing device suitable for carrying out the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Toner tank 2 Toner carrier 3 Toner layer thickness regulating member 4 Toner supply member 5 Photoconductor 6 Stirrer blade 7 Toner 8 Development interval

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazuhiko Umemura 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company (72) Inventor Minoru Masuda 1-3-6 Nakamagome, Ota-ku, Tokyo Stock Inside Ricoh Company (72) Kosuke Suzuki 1-3-6 Nakamagome, Ota-ku, Tokyo Stock Company Ricoh Company (72) Inventor Tomomi Tamura 1-3-6 Nakamagome, Ota-ku, Tokyo Stock Company Ricoh ( 72) Inventor Yasuo Asahina 1-3-6 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Co., Ltd. 2H005 AA01 AA21 CA07 CA08 CA15 EA06 EA07 EA10

Claims (8)

[Claims] 1. A dry electrophotographic toner comprising at least a colorant and a binder resin as main components, wherein the binder resin comprises: I) (a) an epoxy resin, (b) a dihydric phenol,
(C) an alkylene oxide adduct of a dihydric phenol or a polyol resin part having a polyoxyalkylene moiety in the main chain obtained by reaction with a glycidyl ether thereof; and II) an alkylene oxide adduct of at least a dihydric phenol or an adduct thereof. A copolymer resin comprising a polyester resin part obtained by the reaction of glycidyl ether and a polyvalent carboxylic acid, wherein the weight ratio of the epoxy resin to the polyester resin part in the polyol resin part is from 95/5 to 60 / 40, that the epoxy resin of the polyol resin part is at least two or more bisphenol type epoxy resins having different number average molecular weights, and that the acid value of the copolymer resin is 5 or less. Characteristic dry electrophotographic toner. 2. The dry electrophotographic toner according to claim 1, wherein the epoxy equivalent of the resin is 20,000 or more. 3. The dry electrophotographic toner according to claim 1, wherein the resin has an acid value of 1 or less. 4. The dry electrophotographic toner according to claim 1, wherein the polycarboxylic acid in the polyester resin portion is a divalent carboxylic acid. 5. The epoxy resin of the polyol resin part comprises a low molecular weight component having a number average molecular weight of 360 to 2,000 and a high molecular weight component having a number average molecular weight of 3,000 to 10,000. 5. The dry electrophotographic toner according to any one of items 1 to 4. 6. The dry electrophotographic toner according to claim 1, wherein the number average molecular weight of the polyester resin part is from 500 to 2,000. 7. The copolymer resin comprises (a) an epoxy resin, (b) a dihydric phenol, (c) an alkylene oxide adduct of a dihydric phenol or a glycidyl ether thereof, and (d) a dihydric phenol. A polyester resin obtained by the reaction of an alkylene oxide adduct or a glycidyl ether thereof with a polycarboxylic acid,
7. The dry electrophotographic toner according to claim 1, which is obtained by reacting (e) a monohydric phenol or a monocarboxylic acid. 8. A full-color image forming apparatus having a toner container containing the dry electrophotographic toner according to claim 1.