JPH0356636B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a positively chargeable electrophotographic toner. More specifically, the present invention relates to a positively chargeable electrophotographic toner having excellent vinyl chloride resistance and charging properties. Recently, with the development of computer peripherals, the development of high-speed printers has become active.
Many of these printers generally employ an electrophotographic method using a laser beam as an optical exposure system. Therefore, the toner used in this type of high-speed printer needs to be positively chargeable due to the characteristics of the electrophotographic photoreceptor used, and the use of such toner is likely to increase in the future. . By the way, the handling of the copies made by the above-mentioned printers has diversified, and for example, the copies are often used or stored in cases made of soft PVC sheets. Depending on this type of usage, plasticizers such as dioctyl phthalate (DOP) contained in the PVC sheet gradually ooze out and plasticize the toner fixed on the copy document. This causes the inconvenience that the toner adheres and damages the copied document. If the copied document is particularly an important document such as a certificate, it is undesirable for the contents to be damaged, and therefore it is required that the toner does not adhere to the PVC sheet (hereinafter referred to as PVC resistance).
Against this background, there is a demand in the art for the development of positively chargeable electrophotographic toners with good vinyl chloride resistance. Conventionally, styrene-acrylic resins have been used as binder resins for electrophotographic toners, regardless of whether they are positively or negatively charged, but none of these resins are completely satisfactory in terms of PVC resistance. do not have. Furthermore, epoxy resins or polyester resins are also used as binder resins other than styrene-acrylic resins, and these exhibit good vinyl chloride resistance. However, epoxy resin-based toners are inferior in offset resistance, while polyester resin-based toners are excellent in fixing strength and offset resistance, but have poor positive charging characteristics. In this way, no matter which conventionally known resin is used, it is possible to have vinyl chloride resistance and positive charging characteristics, and to simultaneously satisfy the general performance requirements required for electrophotographic toners, such as offset resistance and fixing strength. At present, positively chargeable toner for electrophotography is not available. The inventors of the present invention focused their studies on polyester resin as a resin with relatively good performance among known binder resins for toner. As already mentioned, polyester resin toner has poor positive charging characteristics. Although it is difficult to explain the cause in detail, we have found that it is largely due to the number of carboxyl groups remaining in the polyester resin, that is, the acid value of the resin. Here, the term "good positive charging characteristics" means that the toner can wait for a sufficient amount of positive charging necessary for the phenomenon of an electrostatic latent image. Known polyester resins for toners are different from highly condensed polyester resins such as polyethylene terephthalate (which cannot be used for toners due to fixing properties and crushability during toner production), and have relatively high acid values. Therefore, it is impossible to provide a sufficient amount of positive chargeability simply by using a positive charge control agent such as nigrosine, which is commonly used as a component of positively chargeable toners, and the positive chargeability is poor. becomes. Based on this viewpoint, the present inventors conducted studies to develop a new polyester resin with excellent raw charging characteristics and a good positive charge control agent, and attempted to develop a positively chargeable toner that solves the above-mentioned problems. As a result, surprisingly, a homopolymer obtained by polymerizing (1) a specific rosin polyester resin as a binder resin and (2) a specific nitrogen-containing vinyl monomer as a positive charge control agent, or a combination of the monomer and styrene. The inventors have discovered that the above object can be satisfied by using a toner containing a copolymer obtained from the present invention, and have completed the present invention. That is, the present invention provides a positively charging electrophotographic toner comprising a positive charge control agent and a colorant dispersed in a binder resin, in which the binder resin includes () rosin glycidyl ester, () dicarboxylic acid or dicarboxylic acid anhydride, ( ) A polyfunctional epoxy compound, at least one crosslinking agent selected from the group consisting of a trivalent or higher polybasic acid or its acid anhydride, and a trivalent or higher polyhydric alcohol, and if necessary () a dihydric alcohol. The glass transition point obtained by the reaction is 50-90℃,
Contains a rosin compound (hereinafter referred to as compound A) having an acid value of 20 (KOHmg/g) or less and a gelation rate of xylene of 99% or less, and as a positive charge control agent, the following general formula (1) is used. : (In the formula, R ¹ is a hydrogen atom or a methyl group, R ² is an alkyl group having 1 to 4 carbon atoms, X is an oxygen atom or an imino group, and n is an integer of 1 to 4.) A homopolymer of or a copolymer of this monomer and styrene (hereinafter referred to as compound B)
This invention relates to a positively chargeable electrophotographic toner containing the following: The positively chargeable electrophotographic toner of the present invention is characterized by excellent vinyl chloride resistance and positive chargeability.
Compared to conventional polyester resins, the rosin-based polyester resin of the present invention has superior positive charging characteristics because its acid value is considerably lower, and because of the compatibility between the polyester resin and the polymer that is the positive charge control agent used in combination with it. This is expected to be due to good solubility. Conventional polyester resins have poor compatibility with the nitrogen-containing positive charge control agent, so
There is no way that the toner can have the positive charging characteristics of the present invention, and due to its non-uniformity, the prepared toner has a wide charge amount distribution, and when it is made into a developer, the charge amount rises slowly. , when developing an electrostatic latent image using such toner,
It is recognized that there are considerable problems such as fogging development easily occurs, toner also tends to scatter, and the scattered toner causes problems such as contamination of the area around the developing device. Furthermore, the toner composition of the present invention has excellent heat resistance, fixing properties, offset resistance and printing durability. Furthermore, since filming and poor cleaning do not occur, there is an advantage that no damage is caused to the photoreceptor. The rosin glycidyl ester () used in the compound A used in the present invention can be prepared by heating and reacting rosin and epihalohydrin in the presence of an alkaline substance such as an organic amine. Examples of the rosin used include gum rosin,
Examples include natural rosins such as uddrosin and tall oil rosin, hydrogenated rosins obtained by modifying these rosins, and disproportionated rosins. Naturally, the active ingredients of rosin, such as abietic acid, dehydroabietic acid, dihydroabietic acid, pimaric acid, and isopimaric acid, are also included. The organic amines are preferably tertiary amines or onium salts thereof, and specific examples of the tertiary amines include triethylamine, dimethylbenzylamine, methyldibenzylamine, tribenzylamine, dimethylaniline, and dimethylcyclohexylamine. , methyldicyclohexylamine, tripropylamine, tributylamine,
Examples include N-phenylmorpholine, N-methylpiperidine, and pyridine. Specific examples of onium salts of tertiary amines include tetramethylammonium chloride, tetramethylammonium bromide, benzyltriethylammonium chloride, allyltriethylammonium bromide, tetrabutylammonium chloride, methyltrioctylammonium chloride, and trimethylamine hydrochloride. Examples include triethylamine hydrochloride, pyridine hydrochloride, and the like. The dicarboxylic acid or dicarboxylic anhydride (hereinafter referred to as dicarboxylic acids) used in the compound A includes orthophthalic acid,
Isophthalic acid, terephthalic acid, endomethylenetetrahydrophthalic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, hexahydrophthalic acid, methylhexahydrophthalic acid, maleic acid,
Examples include fumaric acid, succinic acid, adipic acid, azelaic acid, sebacic acid, alkenylsuccinic acids having 8 to 18 carbon atoms, alkylsuccinic acids having 8 to 18 carbon atoms, and acid anhydrides thereof. Examples of the crosslinking agent () used in the compound A include the following compounds. Examples of the polyfunctional epoxy compound include an epoxy resin which is a condensate of bisphenol A and epihalohydrin, and rosin diepoxide or rosin triepoxide which is a reaction product of acrylated rosin or fumarized rosin and epihalohydrin. The rosin used for the polyepoxide of the rosin is the same as that used for the rosin glycidyl ester. Examples of trivalent or higher polybasic salts or anhydrides thereof include trimetic acid, pyromellitic acid, and acid anhydrides corresponding to these. Examples of trihydric or higher polyhydric alcohols include glycerin, trimethylolethane, trimethylolpropane, and pentaethythritol. In the present invention, if necessary, a dihydric alcohol () may be used in place of Compound A. In other words, dihydric alcohol has other constituent components (),
It is used to adjust the glass transition point of Compound A obtained by reacting () and () and to improve the fixing properties. () used in the present invention
There are no particular restrictions on the dihydric alcohol, and examples include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, bisphenol A, and water. Examples include added bisphenol A, ethoxylated bisphenol A, and propoxylated bisphenol A. The amount of dihydric alcohol used is
It may be determined appropriately by considering the glass transition point of
Up to 70 of the usual rosin glycidyl esters
Up to mol% can be used. The method for producing the rosin-based polymer compound used in the present invention includes simultaneously charging the rosin glycidyl ester, the dicarboxylic acids, and the crosslinking agent, and carrying out a heating reaction in the presence or absence of the organic amine as a reaction catalyst. Alternatively, a rosin glycidyl ester and a dicarboxylic acid may be reacted by heating in the presence or absence of an organic amine, a crosslinking agent may be added during or after the reaction, and the reaction may be further heated. In that case, the molar ratio of rosin glycidyl ester and dicarboxylic acid used is preferably 1:1. However, this does not apply when dihydric alcohol is used. More on that later. On the other hand, the amount of the crosslinking agent to be used must be appropriately and carefully determined since it has a significant effect on the physical properties, particularly the molecular weight and molecular weight distribution, of the resulting toner binder resin. The amount of the polyfunctional epoxy compound used among the crosslinking agents may be determined by considering the number of functional groups of the compound, that is, the epoxy equivalent,
Normally, when the total number of moles of rosin glycidyl ester and dicarboxylic acids is 1 mole, for example, for fumarized rosin triglycidyl ester,
The amount is 0.005 to 0.07 mol, preferably 0.005 to 0.04 mol. In the case of commercially available bisphenol type epoxy resins, 0.005 to 0.14 mol, preferably 0.005 to 0.14 mol,
It is preferable to set it at 0.07 mol. Similarly, polyhydric carboxylic acids or polyhydric alcohols also take into consideration the number of their functional groups, and are usually 0.005 to 0.3 mol, preferably 0.005 in the case of trihydric acids, relative to the total number of moles of rosin glycidyl ester and dicarboxylic acids. Use within the range of ~0.15 mol. In the present invention, it is not necessary to carry out the reaction in the presence of organic amines, but depending on the type of dicaronic acid used, it may be used to shorten the reaction time. It is preferably within the range of 0.01 to 5% (weight %, hereinafter the same), preferably 0.05 to 1%. In addition, in the present invention, the binder resin of the toner of the present invention can be obtained in a high yield regardless of the presence or absence of a solvent during the reaction. It is also possible to use The solvent is determined in consideration of azeotropy with the produced water, nonreactivity with rosin glycidyl ester, dicarboxylic acids, and crosslinking agents, and specific examples include toluene and xylene. In the present invention, the reaction temperature and reaction time, which are the reaction conditions for producing the compound A, are appropriately determined in consideration of the yield of the product, but when an acid anhydride is used as the dicarboxylic acid, the reaction temperature is 100%.
-250°C, preferably 130-180°C, 150-300°C when dicarboxylic acid is used, preferably 180-180°C
260℃, and in each case the reaction time is 0.5-10
The time is preferably 1 to 8 hours. If a solvent is used during the reaction, the solid content can be obtained by distilling it off under reduced pressure. By the production method described above, the novel rosin-based polymer compound used in the present invention can be obtained in high yield. In addition, the end point of the reaction in the present invention is
It can be easily determined by appropriately measuring the gelation rate with respect to xylene. Note that the gelation rate with respect to xylene referred to herein means the insolubility rate with respect to xylene. The rosin-based polymer compound obtained in the present invention has excellent properties as an electrophotographic toner, that is, positive charging properties and PVC resistance, and also has a glass transition point in consideration of heat resistance, offset resistance, and fixing properties. is 50~
The temperature is preferably 90°C, preferably 60 to 75°C, and the gelation rate with respect to xylene is 99% or less, preferably 80% or less. That is, if the glass transition point is less than 50°C, the offset resistance will be poor, while if it exceeds 90°C, the fixing property will be poor. If the gelation rate exceeds 99%, it is difficult to produce Compound A, and the workability during toner production (for example, kneading with carbon black) is poor. The acid value (KOHmg/g) of Compound A is usually preferably 20 or less since it affects the positive charging characteristics. When the acid value exceeds 20, the desired positive charging characteristics are not exhibited, and there is a drawback that the charge build-up is poor and fogging occurs. In addition, in the toner of the present invention, a binder resin other than Compound A may be appropriately contained within a range that does not reduce the effects of the present invention. On the other hand, in the present invention, the compound B, which is a positive charge control agent, refers to a homopolymer of a nitrogen-containing vinyl monomer represented by the general formula (1) or a copolymer of the monomer and styrene. Here, the nitrogen-containing vinyl monomers include N,N-dimethylaminomethyl acrylate, N,N-diethylaminomethyl acrylate, N,N-dimethylaminoethyl acrylate, N,N-diethylaminoethyl acrylate, N,N-dimethylaminopropyl Examples include acrylates, acrylates such as N,N-dimethylaminobutyl acrylate, and various methacrylates corresponding thereto. Furthermore, acrylamides such as N,N-dimethylaminoethyl acrylamide, N,N-diethylaminoethyl acrylamide, N,N-dimethylaminopropylacrylamide, N,N-diethylaminopropylacrylamide, and various methacrylamides corresponding to these are also available. I can give an example. Regarding the copolymer that can be used as a positive charge control agent, there is no particular restriction on the copolymerization ratio of the nitrogen-containing vinyl monomer and styrene.
In order to impart the desired positive charge characteristics to the toner, the larger the copolymerization ratio of the nitrogen-containing vinyl monomer, the less the amount of positive charge control agent used can be reduced. When considering workability during pulverization, heat resistance of the resulting toner, etc., it is desirable that the toner has a certain glass transition point (usually 50° C. or higher), and this can be adjusted by adjusting the styrene content. In any case, compound B
The composition of compound B may be appropriately determined by taking into consideration the amount of the control agent used and pulverization workability, etc. Compound B has a polymerization ratio of the monomer of the general formula (1) and styrene.
The ratio is preferably 100:0 to 1:99 (unit: mol%). Regarding the production of the compound B, there are no particular restrictions, and conventionally known solution polymerization methods, bulk polymerization methods, etc. can be used as they are, but the solution polymerization method is preferred because the heat generation during polymerization can be easily controlled. It is better to adopt At this time, the solvents that can be used are:
There is no particular restriction as long as it is inert to the various monomers used, and examples include benzene, toluene, and xylene. In the toner of the present invention, a positive charge control agent other than compound B may be appropriately contained within a range that does not reduce the effects of the present invention. The toner of the present invention contains the compound A and the compound B.
The content of both components in the toner is not limited in any way. For example, when the reaction of Compound A is completed, Compound B is added directly into the reaction vessel and mixed and dissolved, and then taken out. Alternatively, when forming a toner, both components are added at the same time as carbon black, etc., and then melted in an extruder.
A method of kneading or the like can be adopted as appropriate. The amount of both components to be mixed is appropriately determined in consideration of positive charging characteristics, vinyl chloride resistance, heat resistance, offset resistance, fixing properties, and the content of the monomer of general formula (1) in compound B. Generally, the amount of compound B relative to compound A is 0.1 to 50%, preferably 1 to 20%. If the mixing ratio is less than 0.1%, there is a disadvantage that the charge amount of the resulting toner tends to fluctuate, while if it exceeds 50%, it will have a negative effect on PVC resistance, heat resistance, offset resistance, and fixing properties. There is a drawback that it causes In the present invention, conventionally known colorants can be used as they are. Such colorants include, for example, carbon black, nigrosine paint, aniline blue, alcohol blue, chrome yellow, ultramarine blue, monoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, lamp black, rose bengal, monastral. Examples include retsudo. Further, the toner of the present invention may include, for example, () iron,
Metal powders such as manganese, nickel, cobalt, and chromium, () iron alloys such as ferrite and magnetite, alloys or compounds of cobalt, nickel, and manganese, and () other conventionally known ferromagnetic materials can also be blended. Further, the toner of the present invention is not limited to a two-component type, but also a one-component type.
It can also be used as a component-based toner. Next, the electrophotographic toner of the present invention will be described with reference to reference examples and examples, but the present invention is not limited to these examples. Reference Example 1 (Manufacture of disproportionated rosin glycidyl ester) Disproportionated rosin (acid value 162, softening point 79) with a purity of 87% (13% is unsaponifiable) was placed in a No. 5 Kolben equipped with a stirring device and a reflux condenser. C), 2000 g of epichlorohydrin, and 1 g of benzyltrimethylammonium chloride were added, and the mixture was reacted at 80° C. for 4 hours. Then, at the same temperature, add granular sodium hydroxide.
160 g was added in portions, the temperature was raised to 100°C, and the reaction was continued for an additional 2 hours. After filtering the precipitated salt, unevaporated epichlorohydrin was distilled off from the filtrate using a rotary evaporator, and volatile components were completely removed under conditions of 2 mmHg and 120°C to obtain the title pale yellow oil (yield 97.2%). ) was obtained. The acid value of this substance is 0.
The epoxy equivalent was 425, and the purity was 84% in terms of epoxy equivalent. Reference Examples 2 to 4 In Reference Example 1, the starting material rosin was gum rosin (purity 91%, acid value 169, softening point 75°C), hydrogenated rosin (purity 89%, acid value 165, softening point 74°C), Thor Oil rosin (purity 87%, acid value 163, softening point 73℃)
Various resins were obtained by carrying out the reaction in the same manner except that each of these resins was changed and used in Reference Examples 2 to 4 in turn. The acid value of Reference Example 2 is 0, the epoxy equivalent is 436.5,
The purity was 82.1%. Reference example 3 has an acid value of 0, an epoxy equivalent of 431.6, and a purity of 83.5%.
Reference example 4 has an acid value of 0 and an epoxy equivalent of 445.5.
The purity was 80.0%. Reference Example 5 (Manufacture of positive charge control agent) 1345 g of styrene, 1353 g of dimethylaminoethyl methacrylate, 1157 g of benzene, and 13.5 g of azobisisobutyronitrile were added to the four-necked colben in No. 5.
g and stirred to dissolve. Then, reaction was carried out at 80° C. for 8 hours under a nitrogen stream to complete the polymerization. The temperature is further increased to remove benzene,
When the temperature reached 180-190°C, volatile components were completely removed under reduced pressure of 50-70 mmHg. The obtained polymer was a colorless and transparent solid, with a glass transition point of 55°C and an amine value of 187.5. Reference Example 6 (Manufacture of positive charge control agent) 1,603 g of styrene, 264 g of dimethylaminopropyl acrylamide, 1,577 g of xylene, and azobisisobutyronitrile were added to the four-necked corbene of No. 5.
56.2g was added and stirred to dissolve. Then, reaction was carried out at 90° C. for 8 hours under a nitrogen stream to complete the polymerization. The temperature was further increased to remove xylene, and when the temperature reached 200°C, volatile components were completely removed under reduced pressure of 50 to 70 mmHg. The obtained polymer was a pale yellow solid with a glass transition point of 75.5°C and an amine value of 50. Reference Example 7 (Production of binder resin for toner and addition of positive charge control agent) 1905 g of disproportionated rosin glycidyl ester obtained in Reference Example 1, 296 g of triethylene glycol,
774 g of terephthalic acid, 102 g of trimellitic anhydride, and 90 g of xylene were placed in a four-necked container in No. 5, and heated at 220°C for 2 hours under a nitrogen stream, and then at 240°C.
The mixture was maintained at 300° C. for 3 hours to carry out the reaction. The water produced during this time was separated and removed. After confirming that the acid value reached approximately 10, xylene was removed to obtain 2,610 g of rosin-based polyester resin. Then, the polymer 79 obtained in Reference Example 5 was added to the reaction system.
g as a positive charge control agent (the addition rate to the rosin polyester resin is 3%), and was sampled while maintaining the temperature at 240°C and a reduced pressure of 70 mmHg to determine the content of the reaction system insoluble in xylene. The reaction was terminated after confirming that . The resulting resin (mixture of rosin polyester resin and polymer) was a pale yellow solid, with a glass transition point of 68°C, a gelation rate of 52% in xylene, and an acid value of 3.2. Reference Example 8 (Production of binder resin for toner and addition of positive charge control agent) 1238 g of disproportionated rosin glycidyl ester obtained in Reference Example 1, propylene oxide adduct of bisphenol A (manufactured by NOF Corporation, DB) −400）800
g, 830 g of terephthalic acid and 89 g of trimethylolpropane were charged, and the reaction was carried out in the same manner as in Reference Example 7 to obtain 2610 g of rosin-based polyester resin. Next, 120 g of the polymer obtained in Reference Example 5 was added as a positive charge control agent, and a further reaction was carried out in the same manner as in Reference Example 7 to obtain a resin mixture. This is a pale yellow solid with a glass transition point of 65°C.
The gelation rate was 40% and the acid value was 4.1. Reference Example 9 (Production of binder resin for toner and addition of positive charge control agent) Rosin glycidyl ester obtained in Reference Example 4
2475g, adipic acid 183g, isophthalic acid 498g and trimellitic anhydride 96g were prepared.
The reaction was carried out in the same manner as above to obtain 2770 g of rosin polyester resin as a binder resin for toner. This was a pale yellow solid with a glass transition point of 75°C, a gelation rate of 39%, and an acid value of 6.5. Next, 56 g of the polymer obtained in Reference Example 5 was added as a positive charge control agent to 2770 g of the obtained polyester resin, and mixed using a kneading extruder. Reference Example 10 (Production of binder resin for toner and addition of positive charge control agent) Rosin glycidyl ester obtained in Reference Example 3
1316 g of triethylene glycol, 338 g of triethylene glycol, 715 g of phthalic anhydride and 135 g of bisphenol A type epoxy resin were charged and reacted in the same manner as in Reference Example 7 to obtain 2120 g of rosin polyester resin as a binder resin for toner. This was a pale yellow solid with a glass transition point of 70°C, a gelation rate of 55%, and an acid value of 8.9. Then, 225 g of the polymer obtained in Reference Example 6 was added to 2120 g of the obtained polyester resin and mixed using a kneading extruder. Reference Example 11 (Production of binder resin for toner and addition of positive charge control agent) Rosin glycidyl ester obtained in Reference Example 2
1545g, bishydroxyethyl terephthalate (Nippon Soda Co., Ltd., BHET) 450g, terephthalic acid
Prepare 834g and 90g of trimellitic anhydride,
A reaction was carried out in the same manner as in Reference Example 7, and a rosin-based polyester resin was used as a binder resin for toner.
I gained 2750g. Next, 320 g of the polymer obtained in Reference Example 6 was added to this.
was added, and the reaction was carried out in the same manner as in Reference Example 7.
The contents were removed before gelation was observed.
The resulting product had a glass transition point of 63°C, a gelation rate of 0, and an acid value of 4.3. Reference Example 12 (Production of binder resin for toner and addition of positive charge control agent) 1508 g of disproportionated rosin glycidyl ester obtained in Reference Example 1, 263 g of triethylene glycol,
Terephthalic acid 513g and trimellitic anhydride 230g
A reaction was carried out in the same manner as in Reference Example 7 to obtain 2000 g of a rosin-based polyester resin as a binder resin for toner. This was a pale yellow solid with a glass transition point of 64°C, a gelation rate of 38%, and an acid value of 25.4. Then, 60 g of the polymer obtained in Reference Example 5 was added as a positive charge control agent to 2000 g of the obtained polyester resin, and mixed using a kneading extruder. Reference example 13 (Production of binder resin for toner and addition of positive charge control agent) Bisphenol A propylene oxide adduct
2200g, terephthalic acid 830g and trimellitic anhydride 85g were charged, and the reaction was carried out in the same manner as in Reference Example 7 to produce a polyester resin containing no rosin.
I gained 2650g. This was a pale yellow solid with a glass transition point of 70°C, a gelation rate of 29%, and an acid value of 12.0. Then, 110 g of the polymer obtained in Reference Example 5 was added as a positive charge control agent to 2650 g of the obtained polyester resin, and the mixture was mixed using a kneading extruder. Examples 1 to 5 and Comparative Examples 1 to 2 Reference Examples 7 to 11 (Examples 1 to 5) and Reference Example 12
Binder polyester resin for toner containing positive charge control agent prepared in ~13 (Comparative Examples 1 and 2)
Carbon Black MA#100 for 100 parts by weight
(manufactured by Mitsubishi Chemical Industries, Ltd.), 5 parts by weight of nigrosine dye Bontron N-06 (manufactured by Orient Chemical Industries, Ltd.)
(manufactured by Sanyo Chemical Industries, Ltd.) and 5 parts by weight of Viscol 550P (manufactured by Sanyo Chemical Industries, Ltd.) were thoroughly mixed and kneaded using an extruder. After cooling, it was coarsely ground to a size of 1 cm square, finely ground with a jet mill, and then classified with an air classifier, with a particle size range of 5 to 20 μm and an average particle size of 13 to 13.8 μm.
Toners 1 to 5 (Examples 1 to 5) and Toner 6
-7 (Comparative Examples 1-2) were obtained. Table 1 shows the physical properties of the resins used and the average particle diameter of the resulting toner.

[Table] Next, 3 parts by weight of each of these toners and 100 parts by weight of iron powder carrier (manufactured by Nippon Tetsuko Co., Ltd., TEF-V) were kneaded to sufficiently triboelectrically charge the toners.
A printing durability test was conducted by placing a CdS binder-based photoreceptor in a negatively charged copying machine. The results are shown in Table 2.

【table】

【table】

[Table] As is clear from Table 2, Toners 6 and 7 had a small amount of charge and a significant fogging phenomenon, and were not suitable for practical use. Furthermore, regarding the fixing properties of each of these toners 1 to 7, we conducted a fixing test using a fixing device equipped with a Teflon heat roll, and found that toner 5, which had a gelation rate of 0, caused high-temperature offset at 205°C.
Other toners did not cause high temperature offset even at 230°C. However, Toner 5 could be used satisfactorily in oil coating fixing. In addition, the following tape peeling test and bending test were performed on the image fixed at 180° C. to examine the fixing strength, and both showed good results. Tape peeling test: After pasting cellophane tape on the copied image, it was visually judged whether the fixed toner would peel off when the tape was peeled off in a direction at an acute angle to the paper. Folding test: Fold the solid black copy,
It was visually determined whether or not the toner in that area would peel off. Furthermore, the copied image obtained by using each of these toners 1 to 7 was superimposed on a PVC sheet (manufactured by Mitsui Toatsu Chemical Co., Ltd.) containing 30% DOP.
℃, when stored for 24 hours in an environment of 100g/ ^cm2
When examining DOP migration (PVC resistance), none of the images adhered to the PVC sheet. For comparison, when we similarly investigated the PVC resistance of copied images obtained with toner made using conventional styrene-acrylic resin (styrene content 70%), we found that most of the images adhered to the PVC sheet. Even the copied image was torn.

Claims (1)

[Scope of Claims] 1. A positively chargeable electrophotographic toner comprising a positive charge control agent and a colorant dispersed in a binder resin, wherein the binder resin includes () rosin glycidyl ester, () dicarboxylic acid or dicarboxylic acid anhydride. ,
and () a glass transition obtained by reacting at least one crosslinking agent selected from the group consisting of a polyfunctional epoxy compound, a trivalent or higher polybasic acid or its acid anhydride, and a trivalent or higher polyhydric alcohol. The point is 50~90℃,
Contains a rosin compound with an acid value of 20 (KOHmg/g) or less and a gelation rate of xylene of 99% or less, and as a positive charge control agent, the following general formula:
(1): (In the formula, R ¹ is a hydrogen atom or a methyl group, R ² is an alkyl group having 1 to 4 carbon atoms, X is an oxygen atom or an imino group, and n is an integer of 1 to 4.) 1. A positively chargeable electrophotographic toner comprising a homopolymer of the monomer or a copolymer of the monomer and styrene. 2. The positive charge control agent is applied to a rosin compound.
The positively chargeable electrophotographic toner according to claim 1, wherein the amount is 0.1 to 50% by weight. 3. In a positively chargeable electrophotographic toner comprising a positive charge control agent and a colorant dispersed in a binder resin, the binder resin includes () rosin glycidyl ester, () dicarboxylic acid or dicarboxylic acid anhydride, () polyfunctionality. A glass obtained by reacting an epoxy compound, at least one crosslinking agent selected from the group consisting of a trivalent or higher polybasic acid or its acid anhydride, and a trivalent or higher polyhydric alcohol, and () a dihydric alcohol. Transition point is 50~90℃,
Acid value is below 20, gelation rate against xylene is 99%
Contains a rosin compound in the following range, and uses the following general formula (1) as a positive charge control agent: (In the formula, R ¹ is a hydrogen atom or a methyl group, R ² is an alkyl group having 1 to 4 carbon atoms, X is an oxygen atom or an imino group, and n is an integer of 1 to 4.) 1. A positively chargeable electrophotographic toner comprising a homopolymer of the monomer or a copolymer of the monomer and styrene. 4. The positive charge control agent is applied to a rosin compound.
The positively chargeable electrophotographic toner according to claim 1, wherein the amount is 0.1 to 50% by weight.