JP2698574B2 - Electrophotographic developer composition - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to an electrophotographic developer composition, and more particularly, to developing an electrostatic image in electrophotography, electrostatic recording, electrostatic printing, etc. The present invention relates to a developer composition for performing the following. [Prior art and problems] As a conventional electrophotographic method, U.S. Pat.
As described in 357809, etc., an electrically latent image is formed by uniformly charging a photoconductive insulating layer, then exposing the layer, and dissipating the charge on the exposed portion. After being formed, the latent image is visualized by adhering a fine powder having a colored charge called toner (developing step), and the obtained visible image is transferred to a transfer material having a transfer function ( Transfer step), permanent fixing by heating, pressure or other suitable fixing method (fixing step). As described above, the toner must have functions required not only in the development step but also in the transfer step and the fixing step. Generally, toner undergoes a mechanical frictional force due to a shearing force and an impact force received during a mechanical operation in a developing device, and deteriorates during copying of thousands to tens of thousands of sheets. To prevent such deterioration of the toner, a tough resin having a large molecular weight that can withstand mechanical frictional force may be used. However, these resins generally have a high softening point, and are non-contact fixing systems such as oven fixing and infrared fixing. In the radiant fixing method, the fixing efficiency is not sufficient due to the poor thermal efficiency, and the thermal efficiency is good in the contact fixing method. Not only causes the fixing device to deteriorate, the curl of the paper, increases the energy consumption, etc., but also causes the production efficiency to significantly decrease when using such a resin to produce finely divided toner. I do. Therefore, binder resin (binding resin)
Cannot be used if the polymerization degree and the softening point are too high. On the other hand, the heat roller fixing method is widely used from low speed to high speed because the heat roller surface and the toner image surface of the sheet to be fixed come into pressure contact with each other, so that the heat efficiency is good.
When the surface of the heating roller comes into contact with the toner image surface, a so-called offset phenomenon is likely to occur, in which the toner adheres to the surface of the heating roller and is transferred to the subsequent transfer paper or the like. In order to prevent this phenomenon, the surface of the heating roller is processed with a material having excellent releasability, such as fluororesin, but the surface of the heating roller is coated with a release agent such as silicone oil to completely prevent the offset phenomenon. doing. However, the method of applying silicone oil or the like is not preferable because it not only increases the size of the fixing device and increases the cost but also complicates the trouble and easily causes trouble. Also, as described in JP-B-55-6895 and JP-B-56-98202, there is a method for improving the offset phenomenon by increasing the molecular weight distribution width of the binder resin, but the degree of polymerization of the resin is increased. It is necessary to increase the fixing temperature. As a further improved method, Japanese Patent Publication No. 57-493,
As described in JP-A-50-44836 and JP-A-57-37353, there is a method for improving the offset phenomenon by making the resin asymmetric or cross-linking, but the fixing point has not been improved. In general, since the minimum fixing temperature is between the cold offset and the hot offset, the usable temperature range is between the minimum fixing temperature and the hot offset. By raising the temperature as much as possible, the usable fixing temperature can be lowered and the usable temperature range can be widened, so that energy saving, high-speed fixing, and prevention of paper curling can be achieved. Further, since two-sided copying can be performed without any trouble, there are many advantages such as intelligent copying machines, accuracy of temperature control of a fixing device, and relaxation of an allowable range. For this reason, there has been a demand for a toner having good fixability and offset resistance. When a styrene-based binder resin is used in order to achieve such requirements, JP-A-49-65232 and JP-A-50-2
No. 8840, JP-A-50-81342, a method of adding a paraffin wax, a low-molecular-weight polyolefin or the like as an anti-offset agent is known. Deteriorates faster,
In the case of a polyester resin, it has been confirmed that even if the above-mentioned offset preventing agent is applied, the effect is small, and that if the amount used is increased, the deterioration of the developer is quick. The present invention has been made to satisfy these requirements, and has an object to prevent offset without applying an anti-offset liquid in a heat roller fixing method, and to fix at a lower fixing temperature, and to develop. An object of the present invention is to provide an electrophotographic developer having good kneadability and pulverizability at the time of manufacturing the agent. Another object of the present invention is to provide a developer for electrophotography which has good fluidity, does not cause blocking, and has a long life (hardly deteriorates). Another object of the present invention is to provide a developer for electrophotography having uniform chargeability and capable of forming a clear and fog-free image. Another object of the present invention is to provide a clear color developer with good transparency. [Means for Solving the Problems] The present inventors have assiduously studied to achieve the above object, and have reached the present invention. That is, the present invention relates to an electrophotographic developer composition comprising a binder resin and a colorant as main components, wherein the polyolefin comprises at least an unsaturated dicarboxylic acid ester represented by the following general formula (I) or (II): It contains a grafted polyolefin wax obtained by graft-copolymerizing a monomer, and the amount of the unsaturated dicarboxylic acid ester monomer to be grafted is 1 to 30 parts by weight based on 99 to 70 parts by weight of the polyolefin. Is binding resin
1 to 30 parts by weight with respect to 99 to 70 parts by weight, and the binder resin comprises a diol component represented by the following general formula (IV):
The present invention relates to a developer composition for electrophotography, which is a polyester resin comprising a copolymer with an acid component selected from a carboxylic acid having a valency of less than 3, an acid anhydride thereof and a lower alkyl ester thereof. (In the formula, R ₁ and R ₂ represent an alkyl group having 1 to 12 carbon atoms, and R ₃ represents H or an alkyl group having 1 to 12 carbon atoms.) (Wherein R is an ethylene or propylene group, x and y are each 1
The above integers are represented, and the average value of x + y is 2 to 7. Examples of the polyolefin to be graft-copolymerized in the present invention include ethylene homopolymers and copolymers, specifically those having a molecular weight of 10,000 to 500 and obtained by pyrolysis of polyethylene produced by a high-pressure method, And high-pressure polymerized polyethylene obtained by radical polymerization of ethylene with hydrogen peroxide and an organic peroxide, or medium- and low-pressure polymerized polyethylene by a coordination anion polymerization method using a modified Ziegler catalyst. Further, 1-butene, 1-hexene, 1-heptene, 1-octene, 1-decene, etc. may be used as a monomer for copolymerization with ethylene for the purpose of improving the dispersibility and fixing property of the wax. In the unsaturated dicarboxylic acid ester monomer represented by the general formula (I) or (II) used as a modified monomer by graft polymerization in the present invention, R ₃ is H
Are preferred, and specifically, dibutyl fumarate, dioctyl fumarate, dibutyl malate, di-2
Examples of the grafted polyolefin wax according to the present invention include a polyolefin represented by the following general formula (III) and an unsaturated dicarboxylic acid ester monomer represented by the general formula (I) or (II). Those obtained by graft copolymerization with a styrene monomer are preferred. (In the formula, R ₄ represents a hydrogen atom or a methyl group, R ₅ represents a hydrogen atom, an alkyl group or an alkoxy group having 1 to 4 carbon atoms.) As the styrene monomer represented by the general formula (III), styrene, α-methylstyrene, p-methylstyrene, p-methoxystyrene, m-methylstyrene, p-isopropylstyrene, pn-butylstyrene, p-tert-butylstyrene and the like. In the present invention, the amount of grafting of the unsaturated dicarboxylic acid ester monomer represented by the general formula (I) or (II) is 1 to 30 parts by weight, preferably 97 to 80 parts by weight of the polyolefin. 3 to 20 parts by weight. If the amount of the unsaturated dicarboxylic acid ester monomer is less than 1 part by weight, the effect of fixing and hot offset is small, and if it exceeds 30 parts by weight, the wax becomes tacky,
The storage stability and fluidity of the toner are reduced. The graft amount of the styrene monomer represented by the general formula (III) is 1 to 30 parts by weight based on 99 to 70 parts by weight of the sum of the polyolefin unsaturated dicarboxylic acid ester monomers,
It is preferably 5 to 20 parts by weight based on 95 to 80 parts by weight of the sum of the polyolefin and the unsaturated dicarboxylic acid ester monomer. If the amount of the styrene monomer is less than 1 part by weight, the effect is small, and if it exceeds 30 parts by weight, the fixability of the toner is reduced. The content of the grafted polyolefin wax in the composition of the present invention is 1 to 30 parts by weight to 99 to 70 parts by weight of the binder resin.
Parts by weight, preferably 2 to 15 parts by weight based on 98 to 85 parts by weight of the binder resin. When the amount of the grafted polyolefin wax of the present invention is less than 1 part by weight, the effect of fixation and offset property is small, and when it exceeds 30 parts by weight, the fluidity of the toner is reduced, and the photoconductor is filmed and charged during printing. The image may be reduced due to the change in the amount. The binder resin in the present invention is a copolymer of a diol component represented by the general formula (IV) and an acid component selected from divalent or higher carboxylic acids, acid anhydrides and lower alkyl esters thereof. Is a non-linear polyester resin. As the diol component represented by the general formula (IV),
For example, polyoxypropylene (2.2) -2,2-bis (4-
Hydroxyphenyl) propane, polyoxypropylene (3.3) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2 .
0) -polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane and the like. In some cases, other polyols such as polyoxypropylene (12) -2,2-bis (4-hydroxyphenyl) propane and polyoxyphenylethylene (3) -2,
2-bis (4-hydroxyphenyl) propane, ethylene glycol, diethylene glycol, propylene glycol, triethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, heptamethylene glycol, octamethylene glycol, nonamethylene glycol, decamethylene glycol , Neopentylene glycol, p-xylylene glycol, m-xylylene glycol, 1,4-cyclohexanedimethanol, 1,4-cyclohexanediethanol, 1,4-cyclohexanediol, 1,3-cyclohexanedimethanol, Glycerin, polyoxyethylene (6) glycerin, polyoxypropylene (12) pentaerythritol, etc. can be added in an amount of about 10 mol% or less in the polyol component. Those having high steric hindrance such as xylphenylethylene (3) -2,2-bis (4-hydroxyphenyl) propane are difficult to progress in reaction, and are highly hydrophilic polyols such as glycerin and polyoxyethylene (6) pentaerythritol. Care must be taken with the resin using, because the image quality of the developer tends to deteriorate. As the divalent or higher carboxylic acid component, divalent carboxylic acids include fumaric acid, maleic acid, succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid And the like. Alkyl succinic acids and alkenyl succinic acids are also preferred carboxylic acids. Examples of the alkyl or alkenyl succinic acid include n-dodecenyl succinic acid, isododecyl succinic acid, n-dodecyl succinic acid, indodecyl succinic acid, n-octyl succinic acid, n-octenyl succinic acid, n-butyl succinic acid, and the like. . Trimeric or higher polycarboxylic acids include trimellitic acid,
Pyromellitic acid, hemimeric acid, trimesic acid and the like. As the polycarboxylic acid, an acid anhydride thereof or a lower alkyl ester thereof may be used. In order to further improve the fixability, a liquid polybutadiene having a carboxyl group in the form of a free acid, an acid anhydride or a lower alkyl ester, or a tetracarboxylic acid having an alkylene group or an alkenylene group may be contained as an acid component. Preferred examples of such a tetracarboxylic acid include those shown in the following (1) to (12). (1) 4-neopentylidenyl-1,2,6,7-heptanetetracarboxylic acid (2) 4-neopentyl-1,2,6,7-heptene (4)-
Tetracarboxylic acid (3) 3-methyl-4-heptenyl-1,2,5,6-hexanetetracarboxylic acid (4) 3-methyl-3-heptyl-5-methyl-1,2,6,
7-heptene (4) -tetracarboxylic acid (5) 3-nonyl-4-methylidenyl-1,2,5,6-hexanetetracarboxylic acid (6) 3-decyridenyl-1,2,5,6-hexanetetracarboxylic acid Carboxylic acid (7) 3-nonyl-1,2,6,7-heptene (4) -tetracarboxylic acid (8) 3-decenyl-1,2,5,6-hexanetetracarboxylic acid (9) 3-butyl- 3-ethylenyl-1,2,5,6-hexanetetracarboxylic acid (10) 3-methyl-4-butylidenyl-1,2,6,7-heptanetetracarboxylic acid (11) 3-methyl-4-butyl-1 , 2,6,7-Heptene (4) -tetracarboxylic acid (12) 3-methyl-5-octyl-1,2,6,7-heptene (4) -tetracarboxylic acid Binder resin used in the present invention Softening point (ASTME-28
The environmental softening point according to −51T) is preferably 90 to 180 ° C. The developer for electrophotography in the present invention is produced by a usual method. Further, as a colorant that can be used in the present invention, for example, in the case of a black toner, various types of carbon black and color toners produced by a thermal black method, an acetylene black method, a channel black method, a furnace black method, a lamp black method, etc. Copper phthalocyanine, monoazo pigment (CIPigment Red 5, CIPigment
Orange 36, CI Pigment Red 22), diazozo pigments (C.
I. Pigment Yellow 83), anthraquinone pigments (CIP
igment Blue 60), disazo dye (Solvent Red 1)
9), rhodamine dyes (Solvent Red 49), etc.
These are thoroughly and uniformly dispersed by a ball mill or the like together with a binder resin and the above-mentioned grafted polyolefin wax, then melt-kneaded in a kneader, pulverized after cooling, and used as a colored powder having an average particle size of 5 to 15 μm, that is, a toner. . As a dry two-component developer, an appropriate amount of the toner is blended with a magnetic powder such as an irregular carrier, a ferrite-based coat carrier, a true-sphere coat carrier, and used as a developer. In addition, magnetic fine powder can be contained in the toner for the purpose of improving the image on the developing mechanism or the image. Examples of the magnetic powder include alloys and compounds containing ferromagnetic elements such as ferrite and magnetite, and the magnetic substance is contained in the final resin in the form of a fine powder having an average grain size of 0.05 to 1 μm in the fusible resin. % By weight can be dispersed and used. EXAMPLES Hereinafter, examples of the present invention will be described, but the present invention is not limited thereto. Example 1 Polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.
2) -2,2-bis (4-hydroxyphenyl) propane,
90 parts by weight of a non-linear polyester resin obtained by condensation polymerization of terephthalic acid, dodecenylsuccinic anhydride and trimellitic anhydride (softening point 122 ° C, glass transition temperature 64 ° C by Koka type flow tester), molecular weight 900 80% by weight of polyethylene (high density type) 10% by weight of dibutyl fumarate
And 3% by weight of an ethylene wax grafted with 10% by weight of styrene and carbon black (manufactured by Cabot Corporation,
(Regal 400R) was mixed in a ball mill, then kneaded, pulverized, and classified to obtain a toner having an average particle size of 11.5 μm. The obtained toner is used as carrier iron powder (manufactured by Nippon Iron Powder Co., Ltd .; EFV
200/300) and the charge amount was measured by a blow-off type charge amount measuring device to be -23 μc / g. 91 g of the toner was charged with carrier iron powder (manufactured by Nippon Iron Powder Co., Ltd .; EFV 20).
0/300) 1209g to prepare a developer, commercially available electrophotographic copier (using amorphous selenium photoreceptor, roller rotation speed is 255mm / sec, heat roller temperature in the fixing device is variable, oil When the image was formed with the coating apparatus removed), a clear image was obtained with no background stain, no bleeding, and no black solid portion. Set the fixing temperature of the fixing device.
When the fixing property and the offset property of the image were evaluated by controlling the temperature at 120 ° C. to 240 ° C., the image was sufficiently fixed at 150 ° C., and the non-offset area was 140 ° C. to 220 ° C. When images were displayed on up to 50,000 sheets, clear images were obtained without any ground fogging or black solid portions missing. The minimum fixing temperature here is 500 g of load on a sand eraser with a bottom of 15 mm × 7.5 mm, rubs 5 times on the image fixed through the fixing machine, and before and after rubbing with a Macbeth reflection densitometer The optical reflection density is measured, and when the fixing rate according to the following definition exceeds 70%, it refers to the temperature of the fixing roller. (However, the image density before rubbing has an OD value of 0.50.) Comparative Example 1 90 parts by weight of the non-linear polyester resin used in Example 1,
Example 1 using 3 parts by weight of an ethylene wax obtained by grafting 90% by weight of polyethylene having a molecular weight of 900 (high-density type) with 10% by weight of styrene and 7 parts by weight of carbon black (Regal 400R manufactured by Cabot Corporation). When a toner was prepared in the same manner and subjected to a fixing property test, the toner was sufficiently fixed at 150 ° C., but the non-offset region was only 140 ° C. to 190 ° C. Example 2 90 parts by weight of a non-linear polyester resin obtained by polycondensation of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, fumaric acid and trimellitic anhydride having a molecular weight of 2,000 Polyethylene (low density type) 80
3 parts by weight of an ethylene wax grafted with 10% by weight of dioctyl malate and 10% by weight of styrene, and 7 parts by weight of carbon black (Regal 400R, manufactured by Cabot Corporation) were converted to toners in the same manner as in Example 1. When an image was formed and a fixing property test was performed, the image was a clear image with no background stain, bleeding, or black solid portion having a high image density.The image was fixed sufficiently at 140 ° C, and the non-offset area was 130 ° C to 200 ° C. ° C. Comparative Example 2 A toner was prepared in exactly the same manner as in Example 2 except that the grafted ethylene wax of Comparative Example 1 was used instead of the grafted ethylene wax used in Example 2, and a fixing property test was performed. The fixing temperature was 160 ° C., and the non-offset temperature range was 140 ° C. to 190 ° C. Comparative Example 3 A commercially available low molecular weight polypropylene wax (molecular weight 30) was used in Example 1 in place of the grafted ethylene wax.
A toner was prepared in exactly the same manner except for using (00), and a fixing test was performed. As a result, the fixing temperature was 150 ° C., but the non-offset temperature range was only 140 ° C. to 190 ° C. Example 3 A toner was produced in exactly the same manner as in Example 1 except that a rhodamine-based red pigment was used instead of carbon black, an image was formed, and a fixing test was performed. As a result, a clear red image was obtained. . Fixing property is sufficient at 140 ° C, non-offset area is 130
C. to 220C. Example 4 A toner was prepared in exactly the same manner as in Example 1 except that the grafted ethylene wax used in Example 1 was replaced with an ethylene wax obtained by grafting 90% by weight of polyethylene having a molecular weight of 2,000 with 10% by weight of dibutyl fumarate. When making, image output and fixing test, clear image without background fogging, no black solid part was obtained, it was sufficiently fixed at 140 ° C, and the non-offset area was 130 ° C to 200 ° C. there were. Example 5 Instead of the grafted ethylene wax used in Example 1, an ethylene wax obtained by grafting 80% by weight of polyethylene having a molecular weight of 900 with 10% by weight of dibutyl fumarate and 10% by weight of p-methylstyrene was used. The toner was produced in exactly the same manner except that the image was formed, an image was obtained, and a fixing test was performed.As a result, a clear image was obtained, the image was sufficiently fixed at 150 ° C., and the non-offset area was 140 ° C. to 230 ° C. . As is clear from the above results, the toner according to the present invention has excellent image quality and life, has excellent non-offset properties as compared with the case where a conventional polyolefin or modified polyolefin wax is used, and has a lower minimum fixing temperature. ,
This toner is most suitable for electrophotographic copying machines using a heat roller.

Continuation of front page    (56) References JP-A-57-211157 (JP, A)                 JP-A-62-129864 (JP, A)                 JP-A-60-147744 (JP, A)                 JP-A-61-130957 (JP, A)                 JP-A-58-16250 (JP, A)                 JP-A-59-189344 (JP, A)

Claims (1)

(57) [Claims] An electrophotographic developer composition mainly comprising a binder resin and a colorant, wherein at least an unsaturated dicarboxylic acid ester monomer represented by the following general formula (I) or (II) is graft-copolymerized to a polyolefin. Containing a grafted polyolefin wax, the graft amount of the unsaturated dicarboxylic acid ester monomer, polyolefin 99-70
The content of the grafted polyolefin wax is 1 to 30 parts by weight, and the content of the grafted polyolefin wax is 1 to 30 parts by weight with respect to 99 to 70 parts by weight of the binder resin. A polyester resin comprising a copolymer of a diol component represented by IV) and an acid component selected from divalent or higher carboxylic acids, acid anhydrides thereof, and lower alkyl esters thereof; Developer composition. (In the formula, R ₁ and R ₂ represent an alkyl group having 1 to 12 carbon atoms, and R ₃ represents H or an alkyl group having 1 to 12 carbon atoms.) (In the formula, R is an ethylene or propylene group, x and y each represent an integer of 1 or more, and the average value of x + y is 2 to 7.) 2. The electrophotographic development according to claim 1, wherein the grafted polyolefin wax is obtained by graft copolymerizing the unsaturated dicarboxylic acid ester monomer and a styrene monomer represented by the following general formula (III) to a polyolefin. Composition. (In the formula, R ₄ represents a hydrogen atom or a methyl group, R ₅ represents a hydrogen atom, an alkyl group or an alkoxy group having 1 to 4 carbon atoms.) The electrophotographic developer composition according to claim 2, wherein the graft amount of the styrene monomer is 1 to 30 parts by weight based on 99 to 70 parts by weight of the sum of the polyolefin and the unsaturated dicarboxylic acid ester monomer. 4. The electrophotographic developer composition according to claim 1, wherein R ₃ is H in the general formula (I) or (II). 5. 2. The electrophotographic developer composition according to claim 1, wherein the polyolefin is polyethylene.