JP4393013B2 - Method for producing toner for developing electrostatic image - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a toner and a two-component developer used in an electrophotographic image forming apparatus.
[0002]
[Prior art]
Conventionally, a dry developer applied to a developing method of an electrophotographic image forming apparatus is a two-component developer in which a carrier (ferrite powder, iron powder, etc.) that is a magnetic substance is mixed with toner, and magnetic powder in the toner itself. It is roughly divided into a one-component developer carried. Any of the above developers is mainly composed of a binder resin, a colorant and a charge control agent. In addition, in the case of a wax for maintaining offset resistance to a heat roll for fixing or a one-component developer Magnetic powder is added as a main component.
[0003]
The charge control agents added to these electrostatic charge image developing toners include metal complex dyes, phthalocyanine pigments, salicylic acid metal complexes, aromatic dicarboxylic acid metal complexes as negative charge control agents, Nigrosine dyes and various quaternary amines are known as charge control agents for positive charging. However, especially when referring to charge control agents for negative charge, metal complex salt type dyes such as chromium and iron have a high negative friction. It is widely used because it is easy to obtain a stable charge and is at a practical level.
[0004]
[Problems to be solved by the invention]
However, coupled with the recent widespread use of electrophotographic image forming apparatuses, quality requirements from customers have become stricter, and improvements in environmental resistance characteristics are required when metal complex dyes are used as charge control agents. Has reached.
That is, when a metal complex dye is added to a toner as a charge control agent, the amount of charge of the toner increases excessively during continuous copying in a low-humidity atmosphere, causing image defects such as fogging in non-image areas. On the other hand, problems such as a decrease in image density due to a decrease in toner charge amount in continuous copying under a high humidity atmosphere have been pointed out.
In order to solve these problems, conventionally, modification of the acrylic component of the styrene / acrylate copolymer resin and improvement of the binder resin, such as adjusting the ratio, titanium oxide as an external additive using silica alone Improvement of fluidity-imparting agent such as changing to combined use with alumina and magnetic powder, and two-component development method to prevent the increase in charge due to the treatment conditions such as curing temperature and the introduction of conductive material into the coating agent However, a toner for developing an electrostatic image satisfying all the characteristics of the toner has not been obtained.
[0005]
The present invention has solved the above problems by the following technical configuration.
Azo metal complex dyes wherein represented by (1) reduction 1, X is a nitro group, sulfonamide group, or a halogen atom, Y is a hydrogen atom, a halogen atom or a nitro group (provided that X and Y are both nitro excluding those of group), M is chromium, the representative of the iron or cobalt atom 1, purifying as 4- butanediamine content is 50ppm or less, in the azo metal complex dye 1,4 A method for producing a toner for developing an electrostatic charge image , comprising a step of measuring a butanediamine content, a binder resin, a colorant, and a step of kneading, pulverizing and classifying the azo metal complex dye as a main component .
(2) The method for producing a toner for developing an electrostatic charge image according to the above (1), wherein the azo metal complex dye is an azo Cr complex dye .
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in detail below. First, the toner constituting the present invention contains a binder resin, a colorant, and a charge control agent as main components. Various conventionally known resins can be used as the resin. For example, polystyrene, poly-P-chlorostyrene, poly-α-methylstyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene -Methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer Polymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene -Vinyl ethyl ketone copolymer, Styrene-butadiene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, styrene copolymer such as styrene-maleic acid ester, polymethyl methacrylate, polyethyl methacrylate, polybutyl methacrylate, Copolymers, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane, polyamide, epoxy resin, polyvinyl butyral resin, rosin, modified rosin, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon Resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax and the like are used alone or in combination.
[0007]
Colorants include carbon black, aniline black, aniline blue, calcoil blue, chrome yellow, ultramarine blue, dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, lamp black, rose bengal, rhodamine. And dyes, pigments, anthraquinone dyes, monoazo and disazo dyes, and quinacridone magenta pigments.
[0008]
When the colorant is carbon black, it is preferable that the primary particle diameter is 25 to 70 nm, particularly 30 to 55 nm, and the specific surface area is 110 m ² / g or less. When such carbon black is used, crushability by melting and kneading and dispersibility with other materials are good.
The content of the colorant may be an amount sufficient to color a toner capable of forming a visible image by development, but in the case of carbon black, for example, 5 to 20 with respect to 100 parts by weight of the binder resin. % By weight is preferred. If it is less than 5% by weight, the increase in charge amount cannot be suppressed, and the image density (ID) decreases. On the other hand, if the amount is more than 20% by weight, the charge amount decreases and fogging occurs.
[0009]
The charge control agent used in the present invention is an azo metal complex dye as shown in Chemical Formula 1.
In the formula, X represents a nitro group, a sulfonamide group, or a halogen atom, Y represents a hydrogen atom, a halogen atom, or a nitro group (provided that X and Y are both nitro groups), and M represents chromium, iron, or Represents a cobalt atom. Among them, the toner using the azo Cr complex dye has excellent characteristics in that the charging speed is high and the charge amount is high.
[0010]
[Chemical 1]
[0011]
Further, azo metal complex dyes in the present invention, the first gas by thermal extraction, the content of 4-butanediamine is required to have been purified to 500ppm or less. The 1, 4-butanediamine than those as impurities during the synthesis of dyes, reduced to 50ppm or less by purifying by methods devising the impurities equal drying process using hot fluidized bed.
[0012]
In the above, 1 in the gas by thermal extraction, the content of 4-butanediamine is the GC-MS value measured at 200 ° C.-5 minutes by (gas chromatography-mass spectrometer, purge and trap method) . Incidentally 1 azo metal complex dye, the content of 4-butanediamine is 80~370ppm before purification.
[0013]
Next, the carrier constituting the two-component developer produced in the present invention will be described in detail.
Career, it is necessary that the core particle surfaces are coated with a coating agent containing 5 to 20 wt% of carbon black.
As the core particles in this case, for example, iron, ferrite, magnetite and other iron, cobalt, nickel and other ferromagnetic metals or alloys or compounds containing these elements can be used, and the average particle size is usually The thickness is preferably about 10 to 500 μm, particularly preferably 20 to 200 μm.
[0014]
In addition, as the resin constituting the resin coating agent, silicone resin, acrylic resin, styrene resin, epoxy resin, polyamide resin, polyester resin, acetal resin, polycarbonate resin, phenol resin, vinyl chloride resin, vinyl acetate resin, cellulose resin, A single or mixed resin such as a polyolefin resin or a copolymer resin of a monomer component of the above resin is applied.
[0015]
In order to produce the carrier referred to in the present invention using these materials, a resin coating agent is prepared by containing 5 to 20% by weight of carbon black in the resin component. At that time, if necessary, a crosslinking agent, a crosslinking accelerator and other additives are mixed, and this is dissolved and dispersed in an organic solvent to prepare a coating solution for the resin coating agent. The obtained coating solution is applied to the surface of the core particles by dipping or dry spraying to form a coating layer, and then the resin is cured by heating or standing to obtain a carrier used in the present invention.
[0016]
In the, reason you coated with coating agent containing carbon black 5 to 20 wt%, not increase the charge amount and the carbon black is less than 5 wt% is suppressed, image density (ID) It will cause a decline. This is because if the amount of carbon black exceeds 20% by weight, the amount of charge is reduced, and fogging may occur.
[0017]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples of the present invention together with comparative examples. In addition, what was described as a charge control agent refers to an azo metal complex dye.
[0018]
Example 1
<Create toner>
Polyester resin (Tg; 61 ° C., Mn; 4,200, Mw; 160,000,
Tetrahydrofuran insoluble content: 14%) 100 parts Polypropylene wax (trade name Biscol 330P manufactured by Sanyo Chemical Industries, Ltd.) 2 parts Carbon black (trade name Black Par 430, manufactured by Cabot Corp.) 6 parts Charge control agent (charge shown in Chemical Formula 1) Select the product name BONTRON S-34 manufactured by Orient Chemical Co., Ltd. as the control agent, and reduce this to 1.4 ppm butanediamine content in the gas by heat extraction. After mixing with a mixer, after kneading with a twin-screw kneader, finely pulverizing with a jet mill pulverizer and classifying with a dry air classifier, a toner having a volume average particle size of 8.5 μm was obtained.
[0019]
Silica (trade name R972, manufactured by Nippon Aerosil Co., Ltd.) is added to the Henschel mixer at a ratio of 0.7% by weight with respect to the obtained toner, and mixed for 5 minutes under the condition that the peripheral speed of the stirring blade is 30 m / sec. Thus, an electrostatic charge image developing toner A of the present invention was obtained.
[0020]
Next, 100 parts of carrier a, in which an acrylic resin coating agent containing 10% by weight of carbon black with respect to the coating agent is coated on the surface of core particles made of magnetite having an average particle diameter of 60 μm, and the toner A4 part are mixed. A two-component developer of the present invention was prepared.
[0021]
Example 2
Two-component developer of Likewise the invention 1 in the gas by thermal extraction, except that the content of 4-butanediamine was used toner B used a charge control agent which is purified so as to 45ppm Example 1 An agent was created.
[0022]
Example 3
4 parts of toner A of Example 1 and 100 parts of carrier b in which an acrylic resin coating agent containing 15% by weight of carbon black with respect to the coating agent is mixed on the surface of the core particles made of magnetite are mixed. A two-component developer was prepared.
[0023]
Example 4
4 parts of toner A of Example 1 and 100 parts of carrier c coated with an acrylic resin coating agent containing 5% by weight of carbon black with respect to the coating agent are mixed on the surface of the core particles made of magnetite. A two-component developer was prepared.
[0024]
Example 5
The two-component developer of the present invention was prepared by mixing 4 parts of toner B of Example 2 and 100 parts of carrier d coated with an acrylic resin coating agent not containing carbon black on the surface of core particles made of magnetite.
[0025]
Example 6
4 parts of the toner B of Example 2 and 100 parts of carrier e in which an acrylic resin coating agent containing 25% by weight of carbon black is coated on the surface of the core particles made of magnetite are mixed. A two-component developer was prepared.
[0026]
Comparative Example 1
1 in the gas by thermal extraction, 4 except that butanediamine content is using the toner C using a charge control agent which is purified so as to 65ppm is two-component developer for comparison in the same manner as in Example 5 It was created.
[0027]
Comparative Example 2
A comparison was made in the same manner as in Example 6 except that toner D containing a charge control agent of BONTRONS-34 manufactured by Orient Chemical Industries Co., Ltd. was used without any purification of 1,4-butanediamine. A two-component developer was prepared.
[0028]
Comparative Example 3
A comparative two-component developer was prepared in the same manner as in Example 1 except that the toner of Comparative Example 1 was used.
[0029]
Comparative Example 4
1 instead of the toner A, except for using the toner D was blended a charge control agent is not performed at all the purification of 4-butanediamine, it created a two-component developer for comparison in the same manner as in Example 3.
[0030]
Table 1 summarizes the toner , 1,4-butanediamine content and carrier, and the carbon black content in the coating agent constituting the developers of the above Examples and Comparative Examples.
[0031]
[Table 1]
[0032]
In addition, the developers of Examples 1 to 6 and Comparative Examples 1 to 4 are loaded into a two-component development type copying machine with a copy speed of 40 sheets / minute (A4 horizontal), and 20,000 copies are continuously copied. The image density, fog and charge amount at the initial stage and after 20,000 sheets were measured.
The measuring method of each characteristic is as follows.
Image density: The density of a 1 cm square solid image in an A4 original with a printing rate of 5% was measured by a Macbeth reflection densitometer RD914.
-Fog: According to Nitto Denshoku Industries Co., Ltd. color meter ZE2000.
-Charge amount: Based on Toshiba Chemical's blow-off charge amount measuring device.
In measuring each characteristic, in order to see environmental dependency, normal temperature and normal humidity (25 ° C., 55% RH), low temperature and low humidity (10 ° C., 20% RH), and high temperature and high humidity (30 ° C., 80% RH) The evaluation was carried out under each atmosphere. The results are as shown in Tables 2-4.
[0033]
[Table 2]
[0034]
[Table 3]
[0035]
[Table 4]
[0036]
As is apparent from the results of Tables 2 to 4, it was confirmed that each example of the present invention has a stable toner charge amount, little environmental dependency, and gives a high-quality image even after repeated use. That is, according to the present invention, the image density is excellent even after repeated use under low temperature and low humidity, normal temperature and normal humidity, and high temperature and high humidity conditions even after the initial and 20,000 copies, and the fog is also higher than the initial value. Although it slightly increased after copying 20,000 sheets, no image defect occurred and its durability was improved. Furthermore, it was confirmed that the charge amount of the toner of the present invention hardly fluctuated during the continuous copying process in any environment.
On the other hand, the developer of the comparative example was confirmed to decrease in the image density in a low temperature and low humidity atmosphere, and the fog tends to increase with continuous copying under normal temperature and high humidity. As a result, a significant decrease in the charge amount was observed after copying 20,000 sheets under low temperature and low humidity.
[0037]
【The invention's effect】
The present invention is as described above. By using an azo metal complex dye as a charge control agent, it suppresses the occurrence of image defects such as increase in fog without decreasing the image density under normal temperature, normal humidity, low temperature and low humidity, and high temperature and high humidity, and its durability The effect of improving the property can be achieved. In addition, by removing impurities contained in the charge control agent, it is possible to provide a safe material free from harmful substances.

Claims (2)

Azo metal complex dyes wherein represented by the following following formula, X represents a nitro group, sulfonamide group, or a halogen atom, Y represents a hydrogen atom, a halogen atom or a nitro group (provided that X and Y are a nitro group together M represents a chromium, iron or cobalt atom] , a step of purifying 1,4-butanediamine content to be 50 ppm or less , 1,4-butane contained in the azo metal complex dye A method for producing a toner for developing an electrostatic charge image , comprising a step of measuring a diamine content, a step of kneading, pulverizing and classifying the binder resin, a colorant, and the azo metal complex dye as main components .
2. The method for producing a toner for developing an electrostatic charge image according to claim 1, wherein the azo metal complex dye is an azo Cr complex dye.