JPH0355820B2 - - Google Patents

Description

[Detailed description of the invention]

[Background of the Invention] The present invention relates to a toner for developing electrostatic images formed in electrophotography, electrostatic printing, electrostatic recording, and the like. The electrostatic charge image development process is a process in which charged fine particles are attracted by electrostatic attraction and adhered to the surface of the electrostatic charge image support, thereby visualizing the electrostatic charge image. Specific methods for carrying out such a development process include a wet development method using a liquid developer in which a pigment or dye is finely dispersed in an insulating organic liquid;
Cascade method, bristle brush method, magnetic brush method, impression method, powder cloud method using a powder developer made of a toner containing a coloring agent such as carbon black dispersed in a binder made of natural or synthetic resin. There are dry developing methods such as The image visualized in the developing step may be fixed on the support as it is, but usually it is transferred to another support such as transfer paper and then fixed. In this way, the toner is not only subjected to the development process, but also to the subsequent processes, that is, the transfer process and the fixing process, so the toner has not only good developability but also the following processes: It is required to have good transfer and fixing properties. Among these, the conditions related to fixing properties are the most severe, and many studies and results have been published in the past on improving the fixing properties of this toner. It is generally advantageous to use a heat fixing method to fix the toner image formed in the developing process or the image to which this is transferred, and this heat fixing method includes the following steps:
There are a non-contact heating fixing method for open fixing and a contact heating fixing method for hot roller fixing. The contact heating fixing method is excellent in that it has high thermal efficiency, and is particularly capable of high-speed fixing and is suitable for fixing in high-speed copying machines. Furthermore, since a relatively low-temperature heat source can be used, this method requires less power consumption, making it possible to downsize the copying machine and save energy. Further, even if paper accumulates in the fixing device, there is no risk of fire, which is also preferable. Although the contact heating fixing method is preferable in various respects as described above, this method has a serious problem of occurrence of an offset phenomenon. This is a development in which a portion of the toner constituting the image is transferred to the surface of the heat roller during fixing, and this is transferred again to transfer paper or the like that is sent next, staining the image.
In order to prevent this offset phenomenon, various proposals have been made and some have been put into practical use. One is to perform fixing while applying a release oil such as silicone oil to the surface of a heated roller, and the other is to provide the toner itself with offset prevention performance. The latter method is superior in that the structure of the fixing device is simple because a silicone oil application mechanism and the like are not required, and maintenance such as replenishment of silicone oil is not required. Therefore, the offset phenomenon occurs when the temperature of the heat roller increases, and therefore, the higher the minimum temperature at which the offset phenomenon occurs (hereinafter referred to as "offset occurrence temperature"), the better the non-offset property is. It can be called toner, but in order for toner to be fixed, it must be heated to a temperature above its softening point. Therefore, in an actual heat roller fixing device, the temperature of the heat roller is lower than that of the toner. The temperature is set at a specific temperature within the fixable temperature range, which is above the softening point and below the offset generation temperature. However, in reality, it is not possible to maintain the temperature of the heat roller completely uniformly at the set temperature, and there are other temperature-related considerations that must be taken into consideration. It is desirable to use a toner that does not impair the advantages of the heat fixing method. In order to increase the temperature at which offset occurs in a toner, it is effective to include a high molecular weight component in the binder resin of the toner. Since toner has a high softening point, the minimum temperature required for fixing the toner (hereinafter referred to as "minimum fixing temperature") becomes high, and the advantage of the contact heat fixing method is lost. Naturally, it is desirable that this minimum fixing temperature be low.
In addition, in order to achieve high-speed fixing or the formation of visible images on both sides of a single sheet of transfer paper, which has become a growing demand recently, the toner used for development must be able to be fixed at a low temperature. Is required. [Prior Art] From the background described above, a means has been developed to improve the releasability of toner and lower the minimum fixing temperature by incorporating low viscosity, high melting point paraffin wax as a release agent into toner particles. was developed. According to this method, when the paraffin wax is heated, it becomes a low viscosity liquid,
When it comes into contact with a hot fixing roller, it liquefies and is released on the surface of the toner particles, and this liquefied wax comes into contact with the surface of the fixing roller, and since wax has releasability, it acts as a binder for the molten toner. This prevents resin etc. from adhering to the surface of the fixing roller, thereby preventing the offset phenomenon.As a result, even if a binder resin with a low softening point is used, the minimum fixing temperature can be reduced while preventing the offset phenomenon. is achieved. However, when using a toner containing paraffin wax, generally an electrostatic image support such as a photoconductive photoreceptor that supports an electrostatic image to be developed, a developing sleeve of a developing device, and a two-component developer are used. When used as a carrier, the characteristics of the carrier etc. deteriorate relatively quickly, making it impossible to obtain a long useful life. This is because the wax component in the toner adheres to the toner, and the reason for this is that in order to reliably obtain the effect of adding wax, it is necessary to increase the content ratio of the wax, and the content ratio of the wax must be considerably increased. This is thought to be because the wax exists in a so-called phase-separated state in the toner particles due to the low dispersibility of the wax and the large domains of the wax in the toner. [Object of the Invention] The present invention has been made based on the above-mentioned circumstances, and its object is to provide a material that has sufficient non-offset properties, has great durability, and is always stable over a long period of time. An object of the present invention is to provide a toner for developing an electrostatic image that can form a good visible image. [Structure of the Invention] The above object is to provide a toner for developing an electrostatic image, which is characterized by containing a wax formed by chemically bonding a fatty acid ester wax or an achillene bis fatty acid amide wax and a paraffin wax. It is achieved by doing so. The present invention will be specifically explained below. In the present invention, in the binder resin particles made of a polymer or copolymer, together with a colorant, a charge control agent, and other necessary toner components,
A toner for developing an electrostatic image is made by containing a wax formed by chemically bonding a fatty acid ester wax or an alkylene bis fatty acid amide wax and a paraffin wax. As the binder resin in the above, those normally used for this type of application can be used, but in practice, styrene resin, acrylic resin, styrene-acrylic copolymer resin, styrene-butadiene copolymer resin, other vinyl resins,
Polyester resin and others are preferred. and,
It is desirable that the material contains an appropriate high molecular weight component so that it itself has non-offset properties. The wax contained in the toner of the present invention is a chemical combination of a fatty acid ester wax or an achillene bis fatty acid amide wax and a paraffin wax. The wax used in the present invention, for example, first introduces a polar group such as a carboxyl group by oxidative modification or acid modification treatment of paraffin wax, and then has a functional group that can react with the polar group of the paraffin wax. It can be obtained by a method of treating a fatty acid ester wax or an achillene bis fatty acid amide wax with a coupling agent such as diisocyanate or carbodiimide. The ratio of the fatty acid ester wax or the achillene bis fatty acid amide wax to the paraffin wax is in the range of 5:95 to 95:5, preferably 10:90 to 90:10, by weight. Specific examples of fatty acid ester waxes or alkylene bis fatty acid amide waxes that provide waxes suitable for the toner of the present invention include the following. (b) Fatty acid esters and partially saponified products thereof Fatty acid esters or partially saponified products thereof having a melting point of about 30 to 130°C, which are produced by reacting saturated or unsaturated fatty acids with saturated or unsaturated aliphatic alcohols. These esters are obtained by partially saponifying the esters or the esters with hydroxides of metals such as sodium, calcium, magnesium, lead, aluminum, barium, and zinc. The fatty acids as raw material components may be either lower or higher, such as valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, undecylic acid, lauric acid, tridecylic acid, myristic acid, and pentadecylic acid. , palmitic acid, margaric acid, stearic acid, nondecylic acid, arahinic acid, behenic acid, lignoceric acid, cerotic acid, montanic acid, melisic acid, hentriacontanonic acid, dotriacontanonic acid, tetratriacontanonic acid, hexa Triacontanonic acid, octatriacontanonic acid, tucacic acid, lindelic acid, lauroleic acid, tuzuic acid, myristoleic acid, zomarinic acid, petroselic acid, oleic acid, elaidic acid, vaccenic acid, gadolenic acid, erucic acid, brassic acid , ceracoleic acid, linoleic acid, linoleic acid, eleostearic acid, linoelaidic acid,
Examples include valinaric acid, arachidonic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and other dicarboxylic acids having a methylene group having 9 to 19 carbon atoms. The aliphatic alcohols as other raw material components may be either lower or higher like fatty acids, and may be monohydric alcohols or polyhydric alcohols, such as methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, etc. , amyl alcohol, caproyl alcohol, caprylyl alcohol, caprylic alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, arachyl alcohol, behenyl alcohol, carnarvil alcohol, seryl alcohol, coryanyl alcohol, myricyl alcohol, merisyl Alcohol, lactyl alcohol, allyl alcohol, crotyl alcohol, 2-butenol-
1,2-petenol-1,3-hexenol-
1,2-hebutenol-1, 10-undecenol-1, 11-dodecenol-1, 12-tridecenol-1, oleyl alcohol, elaidyl alcohol, linoleyl alcohol, linolenyl alcohol, ethylene glycol, propylene glycol, trimethylene glycol, 1,
3-butanediol, 1,4-butanediol, 2,3-butanediol, 2-butene-
1,4-diol, 1,5-bentanediol, 2,4-pentanediol, 1,6-hexanediol, 2,5-hexanediol, 2
-Methyl-1,3-pentanediol, 2,4
-heptanediol, 2-ethyl-1,3-hexanediol, 2-ethyl-2-butyl-
1,3-propanediol, hexadecane-
1,2-diol, octadecane-1,2-diol, eicosane-1,2-diol, docosane-1,2-diol, tetracosane-1,
Examples include 2-diol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, glycerin, pentaerythritol, and sorbitol. However, when either the fatty acid or the aliphatic alcohol is of a lower grade, those of a higher grade are particularly suitable for use in the present invention. That is, among these esters composed of fatty acids and aliphatic alcohols, fatty acids with a total number of carbon atoms of 5 or more are desirable, and esters with a total number of carbon atoms of 20 or more are particularly preferred. Gives good results in invention. In the present invention, these aliphatic esters or partially saponified products thereof may be used alone, or a mixture consisting of a mixture of various fatty acid esters, or a mixture of fatty acid esters and partially saponified products thereof may be used. It may also be used as a mixture consisting of a mixture of compounds and compounds. In the present invention, commercially available fatty acid esters or partially saponified products thereof can be effectively used, and many of these commercially available products have the composition of a mixture as described above. Typical commercially available products include the following. Lower alcohol esters of fatty acids “Butyl Stearate” (manufactured by Kawaken Fine Chemicals Co., Ltd.) “Butyl Stearate” (manufactured by Kao Soap Co., Ltd.) Polyhydric alcohol esters of fatty acids “Nitsun Castor Wax-A” (Nippon Oil Co., Ltd.) ``Diamond Wax'' (manufactured by Shin Nihon Rika Co., Ltd.) ``Castor Hard'' (manufactured by Kawaken Fine Chemical Co., Ltd.) Higher alcohol ester of fatty acids ``Sparm Acetate'' (manufactured by Nippon Oil & Fats Co., Ltd.) Hoechst Wax-E (manufactured by Hoechst Japan, cetyl palmitate) "Hoechst Wax-OP" (manufactured by Hoechst Japan, partially saponified butylene glycol ester of montanic acid) Partial esters of fatty acids and polyhydric alcohols "Monogly M" (manufactured by NOF Corporation, α-glycerol monostearate) "Fatty acid monoglyceride R-60" (manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd., stearic acid monoglyceride) "Fatty acid monoglyceride R-80" (manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd., oleic acid-stearic acid-monoglyceride) ``Rikemar-S-200'' (manufactured by Riken Vitamin Oil Co., Ltd., glycerin stearate) ``Rikemar-B-100'' (manufactured by Riken Vitamin Oil Co., Ltd., glycerin monoglyceride) ``Rikemar-S-300'' (manufactured by Riken Vitamin Oil Co., Ltd., sorbitan monostearate) ``Rikemar-PS-100'' (manufactured by Riken Vitamin Oil Co., Ltd., propylene glycol monostearate) ``ATMUL-T-95'' ” (manufactured by Kao Atlas Co., Ltd., high-purity monoglyceride) Mixed ester “VLTN-4” (manufactured by Kawaken Fine Chemical Co., Ltd.) “VLT-L” (manufactured by Kawaken Fine Chemical Co., Ltd.) “K-3Wax” (manufactured by Kawaken Fine Chemical Co., Ltd.) (Manufactured by Fine Chemical Co., Ltd.) "Rice wax" (Manufactured by Noda Watkus Co., Ltd.) "Carnauba wax" (manufactured by Noda Watkus Co., Ltd.) For example, the following can be cited as representative examples. 1 C ₁₀ H ₂₁ CO−NH−(CH ₂ ) ₅ −NH−
OCC ₁₀ H ₂₁ 2 C ₁₁ H ₂₃ CO−NH−(CH ₂ ) ₄ −NH−
OCC ₁₁ H ₂₃ 3 C ₁₃ H ₂₇ CO−NH−(CH ₂ ) ₂ −NH−
OCC ₁₈ H ₃₇ 4 C ₁₀ H ₂₁ CO−NH−(CH ₂ ) ₂ −NH−
OCC ₁₄ H ₂₉ 5 C ₁₅ H ₃₁ CO−NH−(CH ₂ ) ₂ −NH−
OCC ₁₅ H ₃₁ 6 C ₁₇ H ₃₅ CO−NH−CH ₂ −NH−OCC ₁₇ H ₃₅ 7 C ₁₇ H ₃₅ CO−NH−(CH ₂ ) ₂ −NH−
OCC ₁₅ H ₃₁ 8 C ₂₃ H ₄₇ CO−NH−CH ₂ −NH−OCC ₁₅ H ₃₁ 12 C ₂₁ H ₄₁ CO−NH−CH ₂ −NH−OCC ₂₁ H ₄₁ 14 C ₁₇ H ₃₁ CO-NH-(CH ₂ ) ₃ -NH-OCC ₁₇ H ₃₁ Examples of commercially available alkylene bis fatty acid amide compounds include the following. “Bisamide” (manufactured by Nitto Kagaku Co., Ltd.) “Plastflow” (manufactured by Nitto Kagaku Co., Ltd.) “Diatsudo 200 Bis” (manufactured by Nippon Hydrogen Co., Ltd.) “Lubloon E” (manufactured by Nippon Hydrogen Co., Ltd.) “Alflo H50S” (manufactured by Nippon Yushi Co., Ltd.) "Alflo V-60" (manufactured by Nippon Oil & Fats Co., Ltd.) "Amido-6L" (manufactured by Kawaken Fine Chemical Co., Ltd.) "Amido-7S" (manufactured by Kawaken Fine Chemical Co., Ltd.) "Amido-6H" (manufactured by Kawaken Fine Chemical Co., Ltd.) (manufactured by Nobuko Chemical Company) "Armowax-EBS" (manufactured by Lion Armor Company) "Hoechst Wax C" (manufactured by Hoechst Company) "Nobuko Wax-22DS" (manufactured by Nobuko Chemical Company) "Adva Wax-280" (manufactured by Advance Company) "Kaoh Wax- EB'' (manufactured by Kao Soap Co., Ltd.) ``Parisin-285'' (manufactured by Baker Castor Oil Co., Ltd.) As the paraffin wax, one having a carbon number of 27 or more and a melting point of 60° C. or more is preferable.
If a toner having a melting point of less than 60° C. is used, a problem arises in that the blocking properties of the toner are reduced. The content of the wax in the toner of the present invention is in the range of 1 to 20% by weight, preferably in the range of 1 to 10% by weight, based on the binder resin. If this proportion is less than 1% by weight, the effect of the wax as a release agent will not be exhibited, and therefore the non-offset property of the toner will not be improved;
If it exceeds 20% by weight, the fluidity of the toner will decrease, resulting in poor developability and transferability, making it impossible to form a good visible image, and the wax may not be present on the developing sleeve or electrostatic image support. adheres to it and forms a film that impedes its function. The wax contained in the toner of the present invention desirably has a low softening point, for example, when measured by the ring and ball method specified in JISK2531-1960.
It is desirable that the temperature is 80-180°C, preferably 90-160°C. The toner of the present invention contains a wax made of the above-mentioned specific chemical substances together with a colorant, a magnetic material, a property improver, and other necessary additives.
It is a granular material that is dispersed in the binder resin described above, and its average particle size is usually in the range of 5 to 30 microns. Coloring agents include carbon black, nigrosine dye (CI No. 50415B), aniline blue (CI No. 50405), and calco oil blue (CI No.
azoec Blue3), Chrome Yellow (CINo.
14090), Ultramarine Blue (CINo.
77103), DuPont Oil Red (CI No.
26105), Quinoline Yellow (CINo.47005), Methylene Blue Chloride (CINo.52015), Phthalocyanine Blue (CINo.74160), Malachite Green Oxalate (CINo.42000), Lampblack (CINo.77266), Rose Bengal (C.
I.No. 45435), mixtures thereof, and others. These colorants need to be contained in a sufficient proportion to form a visible image with sufficient concentration, and are usually contained in a proportion of 1 to 20 parts by weight per 100 parts by weight of the binder resin. . The magnetic material may be a ferromagnetic metal or alloy such as iron, cobalt, or nickel, including ferrite and magnetite, or a compound containing these elements, or a material that does not contain a ferromagnetic element but is subjected to appropriate heat treatment. Mention may be made of alloys which thus become ferromagnetic, such as alloys of the type called Heusler alloys containing manganese and copper, such as manganese-copper-aluminum, manganese-copper-tin, or chromium dioxide, among others. These magnetic materials have an average particle size of 0.1 to 1
Uniformly dispersed in the binder in the form of micron fine powder. And its content is toner 100
The amount per part by weight is 20 to 70 parts by weight, preferably 40 to 70 parts by weight. The property improving agents include charge control agents, anti-offset agents, lubricants for improving fluidity, and others. The toner of the present invention is mixed with a carrier made of iron powder, glass beads, etc. to make a two-component developer, but when it contains a magnetic material, it can be directly used as a one-component developer for developing electrostatic images. . [Effects of the Invention] Since the toner of the present invention contains the specific wax as described above, it has excellent non-offset properties and can be used many times. A good visible image can be formed stably over a long period of time. The reason why the toner of the present invention has such excellent properties has not been strictly elucidated, but it is possible that the wax contained is a chemical combination of fatty acid ester wax or alkylene bis fatty acid amide wax and paraffin wax. Therefore, the excellent mold release properties of the paraffin wax part are effectively exhibited and the non-offset properties of the toner are greatly improved. Since the portions having polar groups are molecularly bonded together, the wax has high compatibility with the binder resin, and is therefore uniformly dispersed in small domains within the toner particles, so that the wax does not spread to the surface of the toner. Therefore, the wax component does not adhere to and contaminate the electrostatic image support, the developing sleeve, the carrier of the two-component developer, etc., and the toner itself has stable characteristics. Part of the reason is thought to be that it has great durability. [Examples] Examples of the present invention will be described below, but the present invention is not limited thereto. Note that "parts" represent parts by weight. The binder resin and wax used in the following examples are as follows. [Binder resin] (1) Binder resin A1 299 g of terephthalic acid, 211 g of polyoxypropylene (2,2)-2,2-bis(4-hydroxyphenyl)propane, and 82 g of pentaerythritol were mixed with a thermometer and stainless steel. Place it in a round-bottomed flask equipped with a steel stirrer, a glass nitrogen gas inlet tube, and a flow-down condenser, set this flask on a mantle heater, and introduce nitrogen gas through the nitrogen gas inlet tube to inert the inside of the flask. Raise the temperature while maintaining the atmosphere,
Furthermore, 0.05 g of dibutyltin oxide is added and the reaction is carried out at a temperature of 200° C. while monitoring the reaction at the softening point. Chloroform insoluble matter 17
Polyester resin (2) by weight, softening point 131°C Binder resin A2 Obtained by copolymerizing styrene, methyl methacrylate, and n-butyl methacrylate in a weight ratio of 50:20:30, with a high The ratio of molecular weight components to low molecular weight components is 40:100 by weight,
Mw=130000, Mn=8000, Mw/Mn=16.25,
Copolymer [wax] with a softening point of 135°C (1) Wax a Melting point obtained by chemically bonding 20 parts of carnauba wax and 80 parts of paraffin wax
Wax at 79.8℃ (2) Wax B 50 parts rice wax and 50 parts paraffin wax
Melting point 105.3 obtained by chemically combining
Wax at °C (3) Wax C Melting point obtained by chemically combining 50 parts of bisamide wax and 50 parts of paraffin wax
Wax at 127°C (4) Wax d Paraffin wax with a melting point of 70°C Example 1 Binder resin A1 100 parts Wax a 3 parts Carbon black "Mogal L" (manufactured by Kyabot Corporation) 10 parts Example 2 Binder resin A2 100 parts Wax b 3 parts Carbon black "Mogul L" 10 parts Example 3 Binder resin A1 100 parts Wax c 3 parts Carbon black "Mogul L" 10 parts Comparative example 1 Binder resin A1 100 parts Wax d 3 parts Carbon black "Mogul L" 10 Part Comparative Example 2 Binder resin A1 100 parts Bisamide wax 1.5 parts Wax d 1.5 parts Carbon black "Mogal L" 10 parts The toners obtained in Examples 1 to 3 and Comparative Examples 1 to 2 above were 1” to “Toner 3” and “Comparison Toner 1” to “Comparison Toner 2”
and for each of the electrophotographic copying machine "U-
20000 using “Bix3000” (manufactured by Konishiroku Photo Industry Co., Ltd.)
A copying test was conducted several times, and the image density of the copied image and the amount of charge of the toner at the initial and final stages were measured. Also, a non-offset type was investigated by setting the temperature of the fixing roller at 230°C. The results are shown in Table 1.

[Table] As is clear from the above results, the toner of the present invention has extremely stable properties and can form good visible images over many times.

Claims (1)

[Claims] 1. A toner for developing electrostatic images characterized by containing a wax formed by chemically bonding a fatty acid ester wax or an alkylene bis fatty acid amide wax and a paraffin wax.