Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G9/00—Developers
  • G03G9/08—Developers with toner particles
  • G03G9/087—Binders for toner particles
  • G03G9/08784—Macromolecular material not specially provided for in a single one of groups G03G9/08702 - G03G9/08775
  • G03G9/08793—Crosslinked polymers

Definitions

• This invention relates to a toner for developing electrostatic images formed in an electrophotographic method, an electrostatic photographic method, an electro­static recording method, etc.
• electrostatic images are developed by a toner which is a coloring powder to form toner images and the toner images are fixed as they are or after being transferred onto a transfer paper, etc.
• the toner is usually prepared by melt-mixing components mainly composed of a polymer as a binder component, carbon black and/or other coloring agent, and a charge controlling agent.
• a low-temperature fixing property is a property inevitable for efficiently forming toner images and, on the other hand, the occurrence of an offset phenomenon, that is, the phenomenon that a part of toner components is transferred onto a heat roller which is usually used for fixing toner images, and stains the surfaces of transfer papers being supplied thereafter or is further transferred onto a press roller which is pressed onto the heat roller, and stains the back surfaces of transfer papers,must be prevented.
• the fixing property of toner is a property originally incompatible with the prevention of the offset phenomenon of the toner but it is a theme to be solved without fail at the practice of toners to prevent the occurrence of the offset phenomenon while keeping the low-temperature fixing property of the toners.
• a method of using a binder resin having a large molecualr weight formed by using a tri- or more-functional monomer as the raw material for the polymer resin and partial-crosslinking the monomer as disclosed in, for example, US Patent 3,938,992 and RE 31,072; a method of incorporating a crosslinking agent in a binder resin composition and partial-crosslinking the resin composition; and a method of using a binder composition composed of a large molecular weight component and an ordinary molecular weight component.
• polyester series resins are known as a binder resin having high performance but have a disadvantage that when a tri- or more-functional monomer such as trimellitic acid, etc., is used as the monomer component, there are no any effective manners to stop the polymerization reaction for obtaining the polymer having a desired molecular weight and a desired degree of crosslinking other than lowering tenperature which makes it difficult to widely and positively promote the use of the toner using the polyester series resin in spite of excellent properties of the resin.
• a tri- or more-functional monomer such as trimellitic acid, etc.
• the binder resin obtained is inferior in performance to the binder resin obtained by the method of using a tri- or more-functional monomer as the monomer component and thus has not yet been used for practice purpose.
• a desired toner for electrostatic images is obtained by using a polyfunctional cyanic acid ester having at least 2 cyano groups in the molecule or a prepolymer of the cyanic acid ester and a curing catalyst for the cyanic acid ester or the prepolymer as a partial cross­linking agent for the resin composition.
• the present has been accomplished based on this novel finding.
• an object of the present invention is a to provide a toner for developing electrostatic images, containing a resin selected from a saturated polyester resin, an acrylic resin, and an epoxy resin as a binder component, wherein the resin has a carboxy group or a glycidyl group and is used as a resin composition containing (a) from 0.5 to 10 parts by weight of a functional cyanic acid ester having 2 or more cyano groups in the molecule or a prepolymer of the cyanic acid ester per 100 parts by weight of the resin and (b) a curing catalyst for the component (a).
• the curing catalyst (b) for the component (a) is previously compounded in the resin composition in a step of from the completion of the polymerization of the resin to the recovery (separation) of the polymerization product;
• the curing catalyst (b) for the component (a) is an organic metal compound;
• the resin composition is prepared by mixing the components at a temperature of from 100 o C to 200 o C;
• the resin composition is prepared by mixing a color­ing agent with the other necessary components for toner;
• the resin is a saturated polyester resin having a glass transition temperature of from 30 o C to 75 o C and an acid value of at least 10 KOHmg/g;
• the resin is an acrylic resin having a glass tran­sition temperature of from 30 o C to 75 o C and an acid value of from 2 to 50 KOHmg/g;
• the resin is an acrylic resin having a glass tran­sition temperature of from 30 o C to 75 o C and a glycidyl group equivalent of
• the resin as a raw material for the binder of the toner of this invention is selected from a saturated polyester resin, an acrylic resin, and an epoxy resin which are conventionally known as a binder resin,and has a carboxyl group and/or a glycidyl group.
• the saturated polyester resin for use in this inven­tion has preferably a glass transition temperature of from 30 o C to 75 o C and an acid value of at least 10 KOHmg/g, has a carboxyl group, and is obtained by condensing an optional acid component and a polyhydric alcohol component.
• the acid component examples include terephthalic acid, isophthalic acid, o-phthalic acid, malonic acid, dimethyl­malonic acid, succinic acid, glutaric acid, adipic acid, trimethyladipic acid, pimelic acid, 2,2-dimethylglutaric acid, azelaic acid, sebacic acid, 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexane­dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 2,5-norbornanedicarboxylic acid, 1,4-naphthalic acid, diphenic acid, 4,4′-oxybenzoic acid, diglycolic acid, thiodipropionic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, benzoic acid, rosin, and resin derivatives such as hydrogenated rosin and
• acids may be acid anhydrides, esters, chlorides, etc., and include, for example, dimethyl 1,4-cyclohexane­dicarboxylate, dimethyl 2,6-naphthalenedicarboxylate, dimethyl isophthalate, dimethyl terephthalate, and diphenyl terephthalate.
• unsaturated carboxylic acids such as maleic acid (anhydride), fumaric acid, etc.
• trihydric or higher hydric carboxylic acids such as trimellitic acid, trimellitic anhydride, pyrromellitic acid, pyrromellitic anhydride, 4-methylcyclohexene-1,2,3-­tricarboxylic acid anhydride, trimesic acid, etc.
• trimellitic acid trimellitic anhydride
• pyrromellitic acid pyrromellitic anhydride
• 4-methylcyclohexene-1,2,3-­tricarboxylic acid anhydride trimesic acid, etc.
• polyhydric alcohol examples include ethylene glycol, diethylene glycol, propylene glycol, 1,3-propane­diol, 2,4-dimethyl-2-ethylhexane-1,3-diol, 2,2-dimethyl-­1,3-propanediol (neopentyl glycol), 2-ethyl-2-isobutyl-­1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-­pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2,2,4-trimethyl-1,6-hexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, 4,
• trihydric or higher hydric alcohols such as pentaerythritol, dipentaerythritol, tripentaery­thritol, glycerol, trimethylolpropane, trimethylolethane, 1,3,6-hexanetriol, etc.
• a compound having a hydroxyl group and a carboxyl group in the molecule such as a low molecular weight condensate of terephthalic acid and ethylene glycol, can be used.
• a sulfonate group can be introduced into the resin by a conventional method.
• the condensing component for use in such a case are 5-sodiosulfoisophthalic acid and 5-potassium-­sulfoisophthalic acid,although the invention is not limited to those compounds.
• polyester resin by condensing the above acid component and polyhydric alcohol, an optional conventionally known method can be used without need of a specific operation.
• the acid component and the polyhydric alcohol of from 1.0 to 1.5 times the amount of the acid component are placed in a reaction vessel together with a catalyst and a dehydrocondensation reaction is carried out with the increase of temperature to 140 o C to 260 o C.
• a catalyst for use in this case there are zinc acetate, zinc chloride, lauryltin oxide, butyltin oxide, octyltin oxide, etc., and the catalyst is usually used in an amount of from 0.05 to 0.15 wt% based on the weight of the dicarboxylic acid.
• a solvent is not always necessary for the reaction but, if desired, an inert solvent such as methyl acetate, benzene, acetone, xylene, toluene, etc., may be used.
• the polyester resin for use in this invention is as described above but it is particularly preferred that the glass transition temperature thereof is from 45 o C to 70 o C and the acid value is from 20 to 60 KOHmg/g. Also, it is preferred that the the number average molecular weight thereof is from 3,000 to 8,000 and the weight average molecular weight thereof is at least 1.0 x 104, and in particular from 5.0 x 104 to 50 x 104.
• the acrylic resin for use in this invention has preferably an acid value of from 2 to 50 KOHmg/g or a glycidyl group equivalent of from 1,000 to 20,000, has a carboxyl group and/or a glycidyl group, and has a glass transition temperature of from 30 to 75 o C.
• the acrylic resin is obtained by polymerizing an alkyl ester component of acrylic acid or methacrylic acid (hereinafter, is referred to as (meth)acrylic acid) and a glycidyl ester component of an unsaturated carboxylic acid or (meth)acrylic acid.
• Examples of the (meth)acrylic acid alkyl ester are the esters such as methyl ester, ethyl ester, propyl ester, butyl ester, 2-ethylhexyl ester, lauryl ester, stearyl ester, etc., of (meth)acrylic acid.
• examples of the unsaturated carboxylic acid component are (meth)acrylic acid, maleic acid, crotonic acid, etc.
• a copolymerizable monomer such as a vinyl ester (e.g., (meth)acrylic acid hydroxyalkyl ester, (meth)acrylic acid alkylene glycol, (meth)acrylamide, (meth)acrylonitrile, dialkylamino (meth)acrylate, styrene, and vinyl acetate may be further copolymerized with above-described components.
• a vinyl ester e.g., (meth)acrylic acid hydroxyalkyl ester, (meth)acrylic acid alkylene glycol, (meth)acrylamide, (meth)acrylonitrile, dialkylamino (meth)acrylate, styrene, and vinyl acetate
• a vinyl ester e.g., (meth)acrylic acid hydroxyalkyl ester, (meth)acrylic acid alkylene glycol, (meth)acrylamide, (meth)acrylonitrile, dialkylamino (meth)acryl
• the acrylic resin For producing the acrylic resin, there are no parti­cular restrictions and an optional known means can be used.
• the production thereof is usually carried out by a solution polymerization using a solvent such as methyl acetate, acetone, benzene, xylene, toluene, etc., in the presence of a radical catalyst, and by removing the remaining monomers and the solvent from the reaction mixture obtained, the acrylic resin for the toner binder is obtained.
• a solvent such as methyl acetate, acetone, benzene, xylene, toluene, etc.
• the acrylic resin has the acid value of from 5 to 30 KOHmg/g or the glycidyl group equivalent of from 1,200 to 8,000, the glass transition temperature of from 45 o C to 70 o C, and the weight average molecular weight of from 2.0 x 104 to 10 x 104.
• the epoxy resin for use in this invention is preferably a di-functional bisphenol A type epoxy resin having a melting point of from 60 o C to 160 o C, and is preferably shown by following formula (1), and the epoxy equivalent of the resin is preferably from 600 to 6,000, and particularly preferably from 800 to 3,500.
• ⁇ represents a benzene nucleus of 1,4-bond and m is usually from about 2 to about 4.
• the polyfunctional cyanic acid ester having at least two cyanato groups (-OCN) in the molecule or a prepolymer of the cyanic acid, which is the component (a) being compounded with the polyester resin, acrylic resin or epoxy resin in this invention, is preferably a compound represented by following formula (2) R(OCN) n (2) wherein R represents an aromatic organic group which may include a heterocyclic ring, the cyanato group being bonded to the aromatic ring of the organic group, and n is an integer of 2 or more, and is usually not more than 5.
• cyanato compound examples include 1,3-­dicyanatobenzene, 1,4-dicyanatobenzene, 1,3,5-tricyanato­benzene, 1,3-, 1,4-, 1,6-, 1,8-, 2,6- or 2,7-dicyanato­naphthalene, 1,3,6-tricyanatonaphthalene, 4,4′-dicyanato­biphenyl, bis(4-dicyanatophenyl)methane, bis(3,5-dimethyl-­4-dicyanatophenyl)methane, 2,2-bis(4-cyanatophenyl)propane, 2,2-bis(3,5-dichloro-4-cyanatophenyl)propane, 2,2-bis(3,5-­dibromo-4-cyantatophenyl)propane, 2,2-bis(3,5-dimethyl-­4-cyanatophenyl)propane, bis(4-cyanatatophenyl) ether, bis(4-cyanatophen
• Patents 4,022,755 and 3,448,079) polyfunctional poly­carbonate cyanates obtained by the reaction of polycarbonate oligomers having a hydroxyl group at the terminal and cyanogen halides
• U.S. Patent 4,026,913 and German Patent 2,611,796 polyfunctional poly­carbonate cyanates obtained by the reaction of polycarbonate oligomers having a hydroxyl group at the terminal and cyanogen halides
• styryl-pyridine-cyanates obtained by the reaction of polyhydroxystyryl-pyridine, etc., which are obtained by reacting hydroxybenzaldehydes and alkyl-­substituted pyridines, and cyanogen halides
• the above polyfunctional cyanic acid esters can be used as prepolymers obtained by polymerizing the cyanic acid esters in the presence of a mineral acid, Lewis acid, a salt (such as sodium carbonate, lithium chloride, etc.), or a phosphoric acid ester (such as tributylphosphine, etc.) or as prepolymers of the cyanic acid esters and polyfunctional amines.
• a mineral acid such as sodium carbonate, lithium chloride, etc.
• a salt such as sodium carbonate, lithium chloride, etc.
• a phosphoric acid ester such as tributylphosphine, etc.
• any catalysts capable of accelerating curing of the component (a) can be usually used.
• Such a catalyst examples include organic peroxides such as benzoyl peroxide, lauroyl peroxide, capryl peroxide, acetyl peroxide, p-chlorobenzoyl peroxide, di-tert-butyl di-peroxide, etc.; azo compounds such as azobisnitrile, etc.; imidazoles such as 2-methylimidazole, 2-undecyl­imidazole, 2-heptadecylimidazole, 2-phenylimidazole, 2-ethyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-propyl-2-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethylimidazole, 1-cyanoethyl-2-undecyl­imidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-­2-
• organic metal compounds such as organic metal salts and organotin compounds (e.g., dibutyltin oxide, dioctyltin oxide, alkyltins, alkyltin oxides, etc.) are preferred.
• organotin compounds e.g., dibutyltin oxide, dioctyltin oxide, alkyltins, alkyltin oxides, etc.
• the amount of the catalyst in this invention is in the range of a general catalyst and is, e.g., from few percents by weight to 10% by weight based on the weight of component (a).
• the compounding amount of the component (a) in this invention is from 0.5 to 10 parts by weight, preferably from 1.0 to 5 parts by weight, and particularly preferably from 1.0 to 2.5 parts by weight,per 100 parts by weight of the raw material resin for binder. If the compounding amount thereof is less than 0.5 part by weight, the effect of this invention is reluctant to obtain, while if the amount is over 10 parts by weight, an excessive crosslinking reaction undesirably occurs to increase the fluidity initiation temperature.
• the toner of this invention is prepared by melt-­mixing a mixture of the resin composition, a coloring agent, and, if necessary, a charge controlling agent; by adding the component (a), the component (b), a coloring agent, and, if necessary, a charge controlling agent to the raw material resin for the binder in place of using the resin composition in this invention followed by melt-mixing; or by producing a so-called master batch composed of the raw material resin for binder compounded with large amounts of the component (a) and the component (b) and melt-mixing the master batch with the raw material resin for binder, a coloring agent, and, if necessary, a charge controlling agent.
• compounding or mixing of the above components is carried out by using an extruder, a press-type kneader, double rolls, etc., at a melt-mixing temperature of from 100 o C to 200 o C, and more preferably from 120 o C to 180 o C, for a melt-mixing time of from about 5 minutes to 30 seconds.
• coloring agent for use in this invention examples include carbon black, Nigrosine dyes, Aniline Blue, Chalco Oil Blue, chrome yellow, ultramarine blue, Do Pont Oil Red, Quinoline Yellow, Methylene Blue Chloride, Phthalocyanine Blue, Malachite Green Oxalate, Lamp Black, Rose Bengale, etc.
• the component (a) reacts with the coloring agent to cause a decoloring reaction and hence in such a case, it is preferred to use the component (a) as a composition or a master batch thereof previously compounded with the raw material resin for the binder.
• Measurement Condition Orifice diameter 1 mm, length 10 mm, load 30 kg.
• the ordinary density of images was measured using Mending Tape No. 810 (made by Sumitomo 3M Co.) and the density retention thereof was measured by a Macbeth densitometer (manufactured by Macbeth Co.).
• the acid value of the polyester resin obtained was 30 KOHmg/g, the melt viscosity thereof at 100 o C was 2 x 104 poise, and the glass transition temperature was 62 o C.
• a mixture of 88 parts of the above polyester resin, 9 parts of carbon black #44 (trade name, made by Mitsubishi Kasei Corporation), 1 part of Bontoron S-34 (trade name, made by Orient Kagaku Kogyo K.K.), 2 parts of Biscoal 550p (trade name, made by Sanyo Chemical Industries, Ltd.), and 2 parts of 2,2-bis(4-cyanatophenyl)­ propane as powders was kneaded using a twin-screw extruder PCM-30 (trade name, manufactured by Ikegai Tekko K.K.) at 60 o C for the 1st cylinder, 140 o C for the 2nd and 3rd cylinders, a shaft rotation number of 100 r.p.m., and a supplying rate of 200 g/min.
• the extruded product was roughly ground to an extent of passing a 1 mm sieve, then finely ground by a jet mill (manufactured by Nippon Pneumatic K.K.), and classi­fied by a pneumatic classifier to provide a toner.
• the melt viscosity of the toner at 140 o C was 4 x 104 poise, the charging amount was -20 ⁇ c/g, and the number average particle size was 0.5 ⁇ m.
• a toner image was transferred onto a plain paper by an electrophotographic copying machine (manufactured by Mita Industrial Co., Ltd.) using a mixture of 5 parts of the toner obtained above and 95 parts of an iron powder TEFV 150/250 (manufactured by Nippon Teppun K.K.) and the paper having the toner image in an unfixed state was passed through a heat roll coated with Teflon (trade name, made by E.I. du Pont de Nemours & Co.) and a backup roll lined with rubber at a speed of 400 mm/sec. to fix the toner image.
• Teflon trade name, made by E.I. du Pont de Nemours & Co.
• the melt visocisty of the toner obtained at 100 o C was 3 x 104 poise, the charging amount was -22 ⁇ c/g, and the number average particle size was 9.3 ⁇ m.
• the result of the image test showed that the toner attached to the heat roll in all the cases of the heat roll temperature of 160 o C, 170 o C, 180 o C, 190 o C, and 200 o C to cause offset and clear images were not obtained in each case.
• Example 2 In the same type of flask as used in Example 1 were placed 0.7 mol of terephthalic acid, 0.3 mol of isophthalic acid, 0.2 mol of ethylene glycol, 0.2 mol of disproportionated rosin monoglyceride, 0.6 mol of a bisphenol A-ethylene oxide addition product, 0.02 mol of trimethylolpropane, and 0.0003 mol of dibutyltin oxide,and the mixture was stirred at 240 o C in a nitrogen gas atmosphere to perform the reaction. When the flow out of water stopped, the temperature of the system was lowered to 180 o C and after further adding thereto 0.07 mol of trimellitic anhydride, the reaction was continued for 30 minutes.
• the acid value of the polyester resin obtained was 32 KOHmg/g, the melt viscosity thereof at 100 o C was 3 x 104 poise, and the glass transition temperature was 60 o C.
• the melt viscosity of the toner at 140 o C was 2 x 104 poise, the charging amount was -25 ⁇ c/g, and the number average particle size was 9.8 ⁇ m.
• the melt viscosity of the toner at 100 o C was 5 x 104 poise, the charging amount was -28 ⁇ c/g, and the number average particle size was 0.3 ⁇ m.
• the result of the image test showed that the toner attached to the heat roll in all the cases of the heat roll temperatures of 160 o C, 170 o C, 180 o C, 190 o C, and 200 o C to cause offset and clear images were not obtained.
• benzoyl peroxide was added to the reaction mixture as a curing catalyst for preparing toner in an amount of 0.1% to the resin.
• a glycidyl group-containing acrylic resin having a glass transition temperaturee of 72 o C, a glycidyl equivalent of 1,800, and a melt viscosity at 120 o C of 1.6 x 104 poise was obtained.
• the melt viscosity of the toner at 140 o C was 6.5 x 104 poise, the charging amount was 15 ⁇ c/g, and the number average particle size was 10.5 ⁇ m.
• a toner image was transferred onto a plain paper by an electrophotographic copying machine DC-162 (manu­factured by Mita Industrial Co., Ltd.) using a mixture of 5 parts of the toner obtained and 95 parts of an iron powder TEFV 150/250 (manufactured by Nippon Teppun K.K.) and the paper having the toner image in an unfixed state was passed through a heat roll coated with Teflon (trade name, made by Du Pont) and a backup roll lined with rubber at a speed of 400 mm/sec. to fix the image.
• the melt viscosity of the toner at 120 o C was 2 x 104 poise, the charging amount was -16 ⁇ c/g, and the number average particle size was 9.3 ⁇ m.
• the result of the image test showed that the toner attached to the heat roll in all the cases of the heat roll temperatures of 180 o C, 190 o C, 200 o C, 210 o C, and 220 o C to cause offset and clear images were not obtained in each case.
• Example 3 By following the same procedure as in Example 3 except that the amounts of the methacrylates were changed to 330 g of methyl methacrylate, 160 g of n-butyl methacrylate, and 10 g of glycidyl methacrylate, a glycidyl group-containing acrylic resin having a glass transition temperature of 71 o C, a glycidyl group equivalent of 7,000, and a melt viscosity at 120 o C of 1.2 x 104 poise was obtained.
• the melt viscosity of the toner obtained at 140 o C was 4 x 104 poise, the charging amount was -18 ⁇ c/g, and the number average particle size was 11.0 ⁇ m.
• the melt viscosity of the toner obtained at 120 o C was 1.5 x 104 poise, the charging amount was -19 ⁇ c/g, and the number average particle size was 10.6 ⁇ m.
• the result of the image test showed that the toner attached to the heat roll in all the cases of the heat roll temperature of 180 o C, 190 o C, 200 o C, 210 o C, and 220 o C and clear images were not obtained in each case.
• Example 3 By following the same procedure as in Example 3 using 155 g of styrene, 220 g of methyl methacrylate, 100 g of 2-ethylhexyl acrylate, 25 g of acrylic acid, 400 g of toluene, and 100 g of isopropyl alcohol, a carboxyl group-containing acrylic resin having a glass transition temperature of 62 o C, an acid value of 27.5 KOHmg/g, and a melt viscosity at 120 o C of 2.1 x 104 poise was obtained.
• the melt viscosity of the toner at 140 o C was 7 x 104 poise, the charging amount was -18 ⁇ c/g, and the number average particle size was 10.5 ⁇ m.
• the melt viscosity of the toner at 120 o C was 5 x 104 poise, the charging amount was -18 ⁇ c/g, and the number average particle size was 10.0 ⁇ m.
• the result of the image test showed that the toner attached to the heat roll in all the cases of the heat roll temperatures of 180 o C, 190 o C, 200 o C, 210 o C, and 220 o C and clear images were not obtained in each case.
• the melt viscosity of the toner at 140 o C was 4.5 x 104 poise, the charging amount was 16 ⁇ c/g, and the number average particle size was 10.6 ⁇ m.
• the melt viscosity of the toner at 120 o C was 2 x 104 poise, the charging amount was -18 ⁇ c/g, and the number average particle size was 10.4 ⁇ m.
• the result of the image test showed that the toner attached to the heat roll in all the cases of the heat roll temperatures of 180 o C, 190 o C, 200 o C, 210 o C, and 220 o C to cause offset and clear images were not obtained in each case.
• the melt viscosity of the toner at 140 o C was 2 x 104 poise, the charging amount was -18 ⁇ c/g, and the number average particle size was 9.5 ⁇ m.
• the melt viscosity of the toner at 120 o C was 3 x 104 poise, the charging amount was -22 ⁇ c/g, and the number average particle size was 9.3 ⁇ m.
• the result of the image test showed that the toner attached to the heat roll in all the cases of the heat roll temperatures of 160 o C, 170 o C, 180 o C 190 o C, and 200 o C to cause offset and clear images were not obtained in each case.
• the melt viscosity of the toner at 140 o C was 2 x 104 poise, the charging amount was -25 ⁇ c/g, and the number average particle size was 9.8 ⁇ m.
• Example 8 The same procedure as in Example 8 was followed except that the use of 2 parts of 1,3,6-tricyanatonaphthalene and 0.1 part of di-n-butyltin was omitted, and a toner was obtained.
• the melt viscosity of the toner at 100 o C was 5 x 104 poise, the charging amount was -28 ⁇ c/g, and the number average particle size was 9.3 ⁇ m.
• the result of the image test showed that the toner attached to the heat roll in all the cases of the heat roll temperatures of 160 o C, 170 o C, 180 o C, 190 o C, and 200 o C to cause offset and clear images were not obtained in each case.
• a toner was prepared according to Example 1, except that a mixture of the polyester resin obtained above and the polyester resin obtained in Example 1 was used in a weight ratio of 6 : 4.
• the toner thus obtained was satisfied with both an offset resistance and a fixing property, and the result of an image test was good as same as in Example 1.
• Example 5 By following the same procedure as in Example 5 except that the acrylic resin thus obtained and the carboxyl group-­containing acrylic resin as used in Example 5 were used at 1 : 1 in weight ratio, a toner was produced.
• the charging amount of the toner was -17 ⁇ c/g and the number average particle size was 10.4 ⁇ m.
• the result of the image test using the toner was good as that of Example 5.
• Example 5 By following the same procedure as in Example 5 except that the acrylic resin thus obtained and the glycidyl group-containing acrylic resin as used in Example 3 were used at a 1 : 1 in weight ratio, a toner was produced.
• the charging amount of the toner was -15 ⁇ c/g and the number average particle size was 10.5 ⁇ m.
• partial crosslinking network formation of a polyester resin, an acrylic resin, or an epoxy resin as the binder resin for the toner can be attained by a simple mixing operation at the preparation of the toner without use of polyfunctional monomers and hence an uncontrollable polymerization operation (i.e., partial crosslinking at polymerization) becomes unnecessary. Accordingly, an inexpensive polyester resin, acrylic resin, or epoxy resin can be used as the binder for the toner.
• the toner of this invention obtained using such a binder resin has a low-temperature fixing property and causes no offset phenomenon, which increases the practical value of the toner.

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• 1989
  • 1989-06-19 EP EP19890111106 patent/EP0347800B1/de not_active Expired - Lifetime
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